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  • kinetics  (286)
  • 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
  • Earthquake risk
  • Geodesy
  • Springer  (312)
  • Elsevier Ltd
  • 2010-2014  (4)
  • 2005-2009  (21)
  • 1995-1999  (288)
  • 1950-1954
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  • 1
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    Comparison of Integrated Geodetic Data Models and Satellite Radar Interferograms to Infer Magma Storage During the 19911993 Mt. Etna Eruption (2005)
    Springer
    Details
    Publikationsdatum: 2017-04-03
    Beschreibung: We compare the results obtained from the modelling of EDM, GPS, levelling and tilt data measured in the first part of the 19911993 eruption at Etna to the InSAR data acquired during the second part. The geodetic changes are very marked in the first half of the eruption and constrain a deflation source located at a few kilometers of depth ( 3 km b.s.l.), in agreement with other independent geophysical evidence. SAR data, available during the second part of the eruption, were analysed for different time intervals in the second part of the eruption. The interpretation of SAR interferograms reveals a large-scale but less marked deflation of the volcano that could be caused by a deeper source. This second source is in accord with a second deeper anomaly revealed by recent seismic investigations. The combination of geodetic data modelling and SAR images suggests a complex plumbing system composed at least of two possible storage regions located at different depths.
    Beschreibung: Published
    Beschreibung: 1345-1357
    Beschreibung: partially_open
    Schlagwort(e): Geodesy ; SAR Interferometry ; ground deformation ; Mt. Etna volcano ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.09. Instruments and techniques
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 2
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    Types of eruptions of Etna volcano AD 16702003: implications for short-term eruptive behaviour (2005)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Analysis of the historical records of Etnas eruptive activity for the past three centuries shows that, after the large 1669 eruption, a period of about 60 years of low-level activity followed. Starting from 1727, explosive activity (strombolian, lava fountaining and subplinian) at the summit crater increased exponentially to the present day. Since 1763, the frequency of flank eruptions also increased and this value remained high until 1960; afterward it further increased sharply. In fact, the number of summit and flank eruptions between 1961 and 2003 was four times greater than that of the pre-1960 period. This long-term trend of escalating activity rules out a pattern of cyclic behaviour of the volcano. We propose instead that the 16702003 period most likely characterises a single eruptive cycle which began after the large 1669 eruption and which is still continuing. On the basis of the eruptive style, two distinct types of flank eruptions are recognised: Class A and Class B. Class A eruptions are mostly effusive with associated weak strombolian activity; Class B eruptions are characterised by effusive activity accompanied by intense, long-lasting, strombolian and lava fountaining activity that produces copious tephra fallouts, as during the 2001 and 20022003 eruptions. Over the past three centuries, seven Class B eruptions have taken place with vents located mainly on the south-eastern flank, indicating that this sector of the volcano is a preferential zone for the intrusion of volatile-rich magma rising from the deeper region of the Etna plumbing system.
    Beschreibung: Published
    Beschreibung: 732-742
    Beschreibung: partially_open
    Schlagwort(e): Etna ; Historical record ; Summit activity ; Flank eruptions ; Eruptive behaviour ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Format: 523 bytes
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  • 3
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    Changes in eruptive style during the A.D. 1538 Monte Nuovo eruption (Phlegrean Fields, Italy): the role of syn-eruptive crystallization (2005)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The Monte Nuovo eruption is the most recent event that occurred at Phlegrean Fields (Italy) and lasted from 29 September to 6 October 1538. It was characterized by 2 days of quasi-sustained phreatomagmatic activity generating pumice-bearing pyroclastic density currents and forming a 130-m-high tuff cone (Lower Member deposits). The activity resumed after a pause of 2 days with two discrete Vulcanian explosions that emplaced radially distributed, scoria-bearing pyroclastic flows (Upper Member deposits). The juvenile products of Lower and Upper Members are, respectively, phenocryst-poor, light-coloured pumice and dark scoria fragments with K-phonolitic bulk compositions, identical in terms of both major and trace elements. Groundmass is formed by variable proportions of K-feldspar and glass, along with minor sodalite and Fe-Ti oxide present in the most crystallized samples. Investigations of groundmass compositions and textures were performed to assess the mechanisms of magma ascent, degassing and fragmentation along the conduit and implications for the eruptive dynamics. In pumice of the Lower Member groundmass crystal content increases from 13 to 28 vol% from the base to the top of the sequence. Products of the Upper Member consist of clasts with a groundmass crystal content between 30 and 40 vol% and of totally crystallized fragments. Crystal size distributions of groundmass feldspars shift from a single population at the base of the Lower Member to a double population in the remaining part of the sequence. The average size of both populations regularly increases from the Lower to the Upper Member. Crystal number density increases by two orders of magnitude from the Lower to the Upper Member, suggesting that nucleation dominated during the second phase of the eruption. The overall morphological, compositional and textural data suggest that the juvenile components of the Monte Nuovo eruption are likely to record variations of the magma properties within the conduit. The different textures of pumice clasts from the Lower Member possibly reflect horizontal gradients of the physical properties (P, T) of the ascending magma column, while scoriae from the second phase are thought to result from the disruption of a slowly rising plug crystallizing in response to degassing. In particular, crystal size distribution data point to syn-eruptive degassing-induced crystallization as responsible for the transition in eruptive style from the first to the second phase of the eruption. This mechanism not only has been proved to profoundly affect the dynamics of dome-forming calc-alkaline eruptions, but may also have a strong influence in driving the eruption dynamics of alkaline magmas of intermediate to evolved compositions.
    Beschreibung: Published
    Beschreibung: 601-621
    Beschreibung: reserved
    Schlagwort(e): Phlegrean Fields ; Vulcanian explosion ; Degassing ; Groundmass crystallization ; Eruption dynamics ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 4
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    Structural features of Panarea volcano in the frame of the Aeolian Arc (Italy): Implications for the 2002–2003 unrest (2009)
    Elsevier Ltd
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Panarea, characterized by gas unrest in 2002–2003, is the volcanic island with the least constrained structure in the eastern-central Aeolian Arc (Italy). Based on structural measurements, we define here its deformation pattern relative to the Arc. The main deformations are subvertical extension fractures (63% of data), normal faults (25%) and dikes (12%). The mean orientation of the extension fractures and faults is ∼N38◦E, with a mean opening direction of N135◦ ±8◦, implying extension with a moderate component of dextral shear. These data, matched with those available for Stromboli volcano (pure opening) and Vulcano, Lipari and Salina volcanoes (predominant dextralmotions) along the eastern-central Arc, suggest a progressivewestward rotation of the extension direction and an increase in the dextral shear. The dextral shear turns into compression in the western arc. The recent unrest at Panarea, coeval to that of nearby Stromboli, may also be explained by the structural context, as both volcanoes lie along the portion of the Arc subject to extension.
    Beschreibung: Protezione Civile, project INGV-DPC-V2
    Beschreibung: Published
    Beschreibung: 288-292
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: 3.2. Tettonica attiva
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: 3.6. Fisica del vulcanismo
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Panarea ; Aeolian Arc ; fault ; dike ; 2002-2003 unrest ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.06. Subduction related processes ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.08. Volcanic arcs ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
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    A multi-disciplinary study of the 200203 Etna eruption: insights into a complex plumbing system (2005)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: The 200203 Mt Etna flank eruption began on 26 October 2002 and finished on 28 January 2003, after three months of continuous explosive activity and discontinuous lava flow output. The eruption involved the opening of eruptive fissures on the NE and S flanks of the volcano, with lava flow output and fire fountaining until 5 November. After this date, the eruption continued exclusively on the S flank, with continuous explosive activity and lava flows active between 13 November and 28 January 2003. Multi-disciplinary data collected during the eruption (petrology, analyses of ash components, gas geochemistry, field surveys, thermal mapping and structural surveys) allowed us to analyse the dynamics of the eruption. The eruption was triggered either by (i) accumulation and eventual ascent of magma from depth or (ii) depressurisation of the edifice due to spreading of the eastern flank of the volcano. The extraordinary explosivity makes the 200203 eruption a unique event in the last 300 years, comparable only with La Montagnola 1763 and the 2001 Lower Vents eruptions. A notable feature of the eruption was also the simultaneous effusion of lavas with different composition and emplacement features. Magma erupted from the NE fissure represented the partially degassed magma fraction normally residing within the central conduits and the shallow plumbing system. The magma that erupted from the S fissure was the relatively undegassed, volatile-rich, buoyant fraction which drained the deep feeding system, bypassing the central conduits. This is typical of most Etnean eccentric eruptions. We believe that there is a high probability that Mount Etna has entered a new eruptive phase, with magma being supplied to a deep reservoir independent from the central conduit, that could periodically produce sufficient overpressure to propagate a dyke to the surface and generate further flank eruptions.
    Beschreibung: Published
    Beschreibung: 314-330
    Beschreibung: partially_open
    Schlagwort(e): Multi-disciplinary study ; Mount Etna ; 2002–03 eruption ; Eccentric eruptions ; Flank activity ; Etna feeding system ; Volcanic processes ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 6
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    Effusive Activity at Mount Etna Volcano (Italy) During the 20th Century: A Contribution to Volcanic Hazard Assessment (2008)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Mount Etna is an open conduit volcano, characterised by persistent activity, consisting of degassing and explosive phenomena at summit craters, frequent flank eruptions, and more rarely, eccentric eruptions. All eruption typologies can give rise to lava flows, which represent the greatest hazard by the volcano to the inhabited areas. Historical documents and scientific papers related to the 20th century effusive activity have been examined in detail, and volcanological parameters have been compiled in a database. The cumulative curve of emitted lava volume highlights the presence of two main eruptive periods: (a) the 1900–1971 interval, characterised by a moderate slope of the curve, amounting to 436 · 106 m3 of lava with average effusion rate of 0.2 m3/s and (b) the 1971–1999 period, in which a significant increase in eruption frequency is associated with a large issued lava volume (767 · 106 m3) and a higher effusion rate (0.8 m3/s). The collected data have been plotted to highlight different eruptive behaviour as a function of eruptive periods and summit vs. flank eruptions. The latter have been further subdivided into two categories: eruptions characterised by high effusion rates and short duration, and eruptions dominated by low effusion rate, long duration and larger volume of erupted lava. Circular zones around the summit area have been drawn for summit eruptions based on the maximum lava flow length; flank eruptions have been considered by taking into account the eruptive fracture elevation and combining them with lava flow lengths of 4 and 6 km. This work highlights that the greatest lava flow hazard at Etna is on the south and east sectors of the volcano. This should be properly considered in future land-use planning by local authorities.
    Beschreibung: Published
    Beschreibung: 407–443
    Beschreibung: 4.3. TTC - Scenari di pericolosità vulcanica
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Mt. Etna ; effusive activity ; database ; lava flow length ; eruptive fractures ; vent elevation ; hazard zonation ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
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    The role of the Pernicana Fault System in the spreading of Mt. Etna (Italy) during the 2002-2003 eruption (2005)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Flank instability and collapse are observed at many volcanoes. Among these, Mt. Etna is characterized by the spreading of its eastern and southern flanks. The eastern spreading area is bordered to the north by the EW-trending Pernicana Fault System (PFS). During the 20022003 Etna eruption, ground fracturing along the PFS migrated eastward from the NE Rift, to as far as the 18 km distant coastline. The deformation consisted of dextral en-echelon segments, with sinistral and normal kinematics. Both of these components of displacement were one order of magnitude larger (~1 m) in the western, previously known, portion of the PFS with respect to the newly surveyed (~9 km long) eastern section (~0.1 m). This eastern section is located along a pre-existing, but previously unknown, fault, where displaced man-made structures give overall slip rates (11.9 cm/year), only slightly lower than those calculated for the western portion (1.42.3 cm/year). After an initial rapid motion during the first days of the 20022003 eruption, movement of the western portion of the PFS decreased dramatically, while parts of the eastern portion continued to move. These data suggest a model of spreading of the eastern flank of Etna along the PFS, characterized by eruptions along the NE Rift, instantaneous, short-lived, meter-scale displacements along the western PFS and more long-lived centimeter-scale displacements along the eastern PFS. The surface deformation then migrated southwards, reactivating, one after the other, the NNWSSE-trending Timpe and Trecastagni faults, with displacements of ~0.1 and ~0.04 m, respectively. These structures, along with the PFS, mark the boundaries of two adjacent blocks, moving at different times and rates. The new extent of the PFS and previous activity over its full length indicate that the sliding eastern flank extends well below the Ionian Sea. The clustering of seismic activity above 4 km b.s.l. during the eruption suggests a deep décollement for the moving mass. The collected data thus suggests a significant movement (volume 〉1,100 km3) of the eastern flank of Etna, both on-shore and off-shore.
    Beschreibung: Published
    Beschreibung: 417-430
    Beschreibung: partially_open
    Schlagwort(e): Volcano spreading ; Fracturing ; Mt. Etna ; Pernicana Fault System ; NE Rift ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 8
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    Role of conduit shear on ascent of the crystal-rich magma feeding the 800-year-b.p. Plinian eruption of Quilotoa Volcano (Ecuador) (2005)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: We have characterized pumice products belonging to the climactic phase of the 800-year-b.p. Quilotoa eruption. Bulk rock compositions, petrography, mineral, and glass chemistry and textural investigations were performed on the three end-member pumice types, namely white, gray, and mingled pumices. All the investigated pumice clasts are dacites characterized by the same bulk rock composition and mineralogical assemblage, but glass compositions and bulk textures change according to different pumice types. White pumice has higher crystallinity (~48 wt%), abundant euhedral pheno/microphenocrysts, no groundmass microlites, the most evolved glass compositions (7478 wt% SiO2), and heterogeneous vesicle populations marked by deformed and highly coalesced vesicles with thin walls. Gray pumice exhibits lower crystallinity (2936 wt%), abundant broken and/or resorbed crystals, ubiquitous groundmass phenocryst fragments and microlites, the widest range of glass compositions (6978 wt% SiO2), and quite homogeneous poorly deformed and coalesced vesicles with thicker walls. Mingled pumices are characterized by the alternation of bands or patches with white and gray pumice compositional and textural characteristics. We attribute heterogeneities in glass compositions and crystal and vesicle textures to processes occurring within volcanic conduits as magma is ascending to the surface. In particular, the above observations and results are consistent with an origin of a gray magma by heating of the original white magma in a strongly sheared region of the conduit because of a mechanism of viscous dissipation and crystal grinding and resorption at the conduit walls. The less viscous gray magma, therefore, would enable the onset and preservation of a high mass flux of the eruption otherwise difficult to explain for highly viscous crystal-rich dacitic magmas.
    Beschreibung: Published
    Beschreibung: 307-321
    Beschreibung: partially_open
    Schlagwort(e): Plinian eruption ; Crystal-rich magma ; Crystal grinding ; Pumice types ; Viscous dissipation ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 9
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    Modeling ground deformations of Panarea volcano hydrothermal/geothermal system (Aeolian Islands, Italy) from GPS data (2010)
    Springer
    Details
    Publikationsdatum: 2017-04-04
    Beschreibung: Panarea volcano (Aeolian Islands, Italy) was considered extinct until November 3, 2002, when a submarine gas eruption began in the area of the islets of Lisca Bianca, Bottaro, Lisca Nera, Dattilo, and Panarelli, about 2.5 km east of Panarea Island. The gas eruption decreased to a state of low degassing by July 2003. Before 2002, the activity of Panarea volcano was characterized by mild degassing of hydrothermal fluid. The compositions of the 2002 gases and their isotopic signatures suggested that the emissions originated from a hydrothermal/geothermal reservoir fed by magmatic fluids. We investigate crustal deformation of Panarea volcano using the global positioning system (GPS) velocity field obtained by the combination of continuous and episodic site observations of the Panarea GPS network in the time span 1995–2007. We present a combined model of Okada sources, which explains the GPS results acquired in the area from December 2002. The kinematics of Panarea volcano show two distinct active crustal domains characterized by different styles of horizontal deformation, supported also by volcanological and structural evidence. Subsidence on order of several millimeters/year is affecting the entire Panarea volcano, and a shortening of 10−6 year−1 has been estimated in the Islets area. Our model reveals that the degassing intensity and distribution are strongly influenced by geophysical-geochemical changes within the hydrothermal/geothermal system. These variations may be triggered by changes in the regional stress field as suggested by the geophysical and volcanological events which occurred in 2002 in the Southern Tyrrhenian area.
    Beschreibung: Published
    Beschreibung: 609-621
    Beschreibung: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): GPS monitoring ; Model ; Gas eruption ; Active volcanism ; Aeolian arc ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
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    Geochemical evidence of the renewal of volcanic activity inferred from CO2 soil and SO2 plume fluxes: the 2007 Stromboli eruption (Italy) (2011)
    Springer
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    Publikationsdatum: 2017-04-04
    Beschreibung: On 27 February 2007, a new eruption occurred on Stromboli which lasted until 2 April. It was characterized by effusive activity on the Sciara del Fuoco and by a paroxysmal event (15 March). This crisis represented an opportunity for us to refine the model that had been developed previously (2002–2003 eruption) and to improve our understanding of the relationship between the magmatic dynamics of the volcano and the geochemical variations in the fluids. In particular, the evaluation of the dynamic equilibrium between the volatiles (CO2 and SO2) released from the magma and the corresponding fluids discharged from the summit area allowed us to evaluate the level of criticality of the volcanic activity. One of the major accomplishments of this study is a 4-year database of summit soil CO2 flux on the basis of which we define the thresholds (low–medium–high) for this parameter that are empirically based on the natural volcanological evolution of Stromboli. The SO2 fluxes of the degassing plume and the CO2 fluxes emitted from the soil at Pizzo Sopra la Fossa are also presented. It is noteworthy that geochemical signals of volcanic unrest have been clearly identified before, during and after the effusive activity. These signals were found almost simultaneously in the degassing plume (SO2 flux) and in soil degassing (CO2 flux) at the summit, although the two degassing processes are shown to be clearly different. The interpretation of the results will be useful for future volcanic surveillance at Stromboli.
    Beschreibung: Published
    Beschreibung: 443-456
    Beschreibung: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Beschreibung: 2.4. TTC - Laboratori di geochimica dei fluidi
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Stromboli volcano ; CO2 soil flux ; Geochemical monitoring ; 2007 eruption ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 11
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    Detecting short-term evolution of Etnean cinder cones: a LIDAR-based approach (2010)
    Springer
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    Publikationsdatum: 2017-04-04
    Beschreibung: The 2001 and 2002–2003 flank eruptions on Mount Etna (Italy) were characterized by intense explosive activity which led to the formation of two large monogenetic scoria cones (one from each eruption) on the upper southern flank of the volcano. Continuous monitoring of Etna, especially during flank eruptions, has provided detailed information on the growth of these cones. They differ in genesis, shape, and size. A set of high resolution (1 m) digital elevation models (DEMs) derived from light detection and ranging (LIDAR) data collected during four different surveys (2004, 2005, 2006, and 2007) has been used to map morphology and to extract the morphometric parameters of the scoria cones. By comparing LIDAR-derived DEMs with a pre-eruption (1998) 10 m DEM, the volume of the two scoria cones was calculated for the first time. Comparison of the LIDAR-derived DEMs revealed in unprecedented detail morphological changes during scoria cone degradation. In particular, the morphologically more exposed and structurally weaker 2002–2003 cone was eroded rapidly during the first few years after its emplacement mainly due to gravitational instability of slopes and wind erosion.
    Beschreibung: Published
    Beschreibung: 1209–1222
    Beschreibung: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Beschreibung: JCR Journal
    Beschreibung: reserved
    Schlagwort(e): Mount Etna ; Scoria cone evolution ; Erosion ; LIDAR ; DEM ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
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    CO2-driven large mafic explosive eruptions: a case study from the Colli Albani Volcanic District (Italy) (2012)
    Springer
    Details
    Publikationsdatum: 2021-12-15
    Beschreibung: Gene rally, the intensity and magnitude of explosive volcanic activity increase in parallel with SiO2 content. Pyro clasti cflow-forming eruptions in the Colli Albani ultrapotassic volcanic district (Italy) repres ent the most striking exception on a global scale, with volumes on the order of tens of cubic kilometres and K-foiditic compositions (SiO2 even〈42 wt.%). Here, we reconstruct the pre-eruptive scenario and event dynamics of the ~456 ka Pozzolane Rosse (PR) eruption, the largest mafic explosive event of the Colli Albani district. In particular, we focus on the driving mechanisms for the unusually explosive eruption of a low-viscosity, mafic magma. Geologic, petrographic and geochemical data with mass balance calculations, supported by experimental data for Colli Albani magma compositions, provide evidence for significant ingestion of carbonate wall rocks by the Pozzolane Rosse K-foiditic magma. Moreover, the scattered occurrence of cored bombs in Pozzolane Rosse pyroclastic-flow deposits records carbonate entrainment even at the eruptive time scale, as also tested quantitatively by thermal modelling of magma–carbonate interaction and carbonate assimilation experiments. We suggest that the addition of free CO2 from decarbonation of country rocks was the major factor controlling magma explosivity. High CO2 activity in the volatile component, coupled with magma depressurisation, produced extensive leucite crystallisation at short time scal s, resulting in a dramatic increase in magma viscosity and volatile pressurisation, which was manifested a change of eruptive dynamics from early effusion to the Pozzolane Rosse's highly explosive eruption climax.
    Beschreibung: Published
    Beschreibung: 241-256
    Beschreibung: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Mafi c explosive erupt ions ; Py roclasti c flow ; Er uption magni tude ; Colli Al bani ; Po tassic volcan ism ; Car bonate assi milation ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 13
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    VLNDEF Project for Geodetic Infrastructure Definition of Northern Victoria Land, Antarctica (2008)
    Springer
    Details
    Publikationsdatum: 2022-05-30
    Beschreibung: Scientific investigations in Antarctica are, for many different reasons, a challenging and fascinating task. Measurements, observations and field operations must be carefully planned well in advance and the capacity of successfully meeting the goals of a scientific project is often related to the capacity of forecasting and anticipating the many different potential mishaps. In order to do that, experience and logistic support are crucial. On the scientific side, the team must be aware of its tasks and be prepared to carry out observations in a hostile environment: both technology and human resources have to be suitably selected, prepared, tested and trained. On the logistic side, nations, institutions and any other organisation involved in the expeditions must ensure the proper amount of competence and practical support. The history of modern Italian Antarctic expeditions dates back to the middle 80’s when the first infrastructures of “Mario Zucchelli Station”, formerly Terra Nova Bay Station, were settled at Terra Nova Bay, Northern Victoria Land. Only a few years later, the first geodetic infrastructures were planned and built. Italian geodetic facilities and activities were, ever since, being constantly maintained and developed. Nowadays, the most remarkable geodetic infrastructures are the permanent Global Positioning System (GPS) station (TNB1) installed at Mario Zucchelli and the GPS geodetic network Victoria Land Network for DEFormation control (VLNDEF) entirely deployed on an area extending between 71° S and 76° S and 160° E and 170° E. These facilities do not only allow carrying out utmost geodetic investigations but also posses interesting capacities on the international multidisciplinary scientific scenario. In order to fully exploit their potentiality, management and maintenance of the infrastructure are crucial; nevertheless, in order to perform high quality scientific research, these abilities must be coupled with the knowledge concerning a proper use and a correct processing of the information that these infrastructures can provide. This work focuses on the different methods that can be applied to process the observations that are performed with GPS technique in Northern Victoria Land, aiming at reaching the highest accuracy of results and assuring the larger significance and versatility of the processing outcomes. Three software were used for the analysis, namely: Bernese v.5.0, Gipsy/Oasis II and Gamit/Globk. The working data sets are (i) the permanent GPS station TNB1 observations continuously performed since 1998 and (ii) the five episodic campaigns performed on the sites of VLNDEF. The two infrastructures can be regarded as neat examples of standard geodetic installation in Antarctica. Therefore, the technological solutions that were adopted and applied for establishing the GPS permanent station and the VLNDEF geodetic network as well as the data processing strategies and the data analysis procedures that were tested on their observation will be illustrated in detail. The results will be presented, compared and discussed. Furthermore, their potentials and role in geodetic research will be carefully described; their versatility will also be highlighted in the foreground of a multidisciplinary Antarctic international scientific activity.
    Beschreibung: Published
    Beschreibung: 37-72
    Beschreibung: 1.8. Osservazioni di geofisica ambientale
    Beschreibung: reserved
    Schlagwort(e): Antarctica ; Geodesy ; Geodetic Infrastructures ; GPS ; 01. Atmosphere::01.01. Atmosphere::01.01.08. Instruments and techniques
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: book chapter
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  • 14
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    Developing Tsunami-Resilient Communities (2005)
    Springer
    In:  Amsterdam, Springer, vol. 1, pp. 225, (1-4020-3353-2)
    Details
    Publikationsdatum: 2005
    Schlagwort(e): Tsunami(s) ; Earthquake risk ; Earthquake precursor: prediction research ; Review article ; Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Modelling ; NATHAZ ; measurement, ; tsunami ; model, ; data ; assimilation, ; data ; inversion, ; tsunami ; warning, ; tsunameters, ; forecast, ; hazard ; mitigation
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    BIBLIOGRAFIE SEISMOLOGIE
  • 15
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    Naturkatastrophen (1995)
    Springer
    In:  Berlin, Springer, vol. 34, no. 22, pp. 65-70, (ISBN 3-7643-0253-4)
    Details
    Publikationsdatum: 1995
    Schlagwort(e): Earthquake precursor: prediction research ; Textbook of geophysics ; Textbook of geology ; Tsunami(s) ; Earthquake hazard ; Earthquake risk
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  • 16
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    Geo-Information for Disaster Management (2005)
    Springer
    In:  Berlin, Heidelberg, New York, Springer, vol. 4, no. 85, pp. 175, (ISBN 3-540-24988-5)
    Details
    Publikationsdatum: 2005
    Schlagwort(e): Textbook of informatics ; Earthquake hazard ; Earthquake risk ; Tsunami(s) ; Proceedings of a conference ; INSPIRE ; OpenGIS ; GIS ; floods ; landslides ; storms ; geography ; Delft ; GFZ ; M ; 06.0234 ; 000303921
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    BIBLIOGRAFIE SEISMOLOGIE
  • 17
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    Iceland Geodynamics - Crustal Deformation and Divergent Plate Tectonics (2006)
    Springer
    In:  Corporate, Florida, Springer, vol. Developments in Petroleum Science vol. 15B, no. Publ. No. 12, pp. 9, (3-540-24165-5, XXVI + 228 p.)
    Details
    Publikationsdatum: 2006
    Beschreibung: This book provides a summary of geodynamic results from Iceland that presently are found in a great number of scientific articles, but have not been collected before in a book
    Schlagwort(e): Textbook of geodesy ; Crustal deformation (cf. Earthquake precursor: deformation or strain) ; Geodesy ; Plate tectonics ; GeodesyY
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    BIBLIOGRAFIE SEISMOLOGIE
  • 18
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    Volcano Deformation - New Geodetic Monitoring Techniques (2006)
    Springer
    In:  Cambridge, Springer, vol. LXXVIII, no. 2, pp. 125-169, (ISBN: 3-540-42642-6, Approx. 620 p. 30 illus., Hardcover)
    Details
    Publikationsdatum: 2006
    Schlagwort(e): Crustal deformation (cf. Earthquake precursor: deformation or strain) ; Volcanology ; Geodesy ; Global Positioning System ; InSAR ; Textbook of geodesy
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  • 19
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    Assessing and Managing Earthquake Risk - Geo-scientific and Engineering Knowledge for Earthquake Risk Mitigation: developments, tools, techniques (2006)
    Springer
    In:  Boston, 362 pp., Springer, vol. 12, 135 pp., no. 85, pp. 175, (1-4020-3524-1, XXV + 543 p., with CD-ROM)
    Details
    Publikationsdatum: 2006
    Beschreibung: This book points out the need of a multidisciplinary approach in the field of risk assessment and management. It provides an overview of the problems, approaches and common practices directly related to earthquake risk mitigation and, in particular, to the preparation of earthquake emergency plans
    Schlagwort(e): Textbook of geophysics ; Textbook of engineering ; Earthquake hazard ; Earthquake engineering, engineering seismology ; Earthquake risk ; Disaster ; management, ; Earthquake ; hazard, ; Emergency ; plans, ; Risk ; assessment ; and ; mapping, ; Seismic ; zonation, ; Vulnerability ; and ; damage
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  • 20
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    The Adria Microplate: Global Positioning System Geodesy, Tectonics and Hazards (2006)
    Springer
    In:  Amsterdam, 490 pp., Springer, vol. 11, no. Publ. No. 12, pp. 127, (1-4020-4233-7 (hc), 1-4020-4234-5 (sc), X + 413 p.)
    Details
    Publikationsdatum: 2006
    Beschreibung: Tectonic motion of the Adria microplate exerts a first-order control on the tectonics, geology, seismology, resource distribution, and the geological hazards across a broad zone of south-central Europe and the north-central Mediterranean... This workshop brought together a distinguished international group of scientists working in the peri-Adriatic region to: (1) review research activities and results, (2) share technical expertise, and (3) provide a springboard for future collaborative research on Adria geodynamics. Areas of agreement were identified, as well as remaining areas of debate. In addition, attention focused on important scientific questions and the potential for international and interdisciplinary research in the future
    Schlagwort(e): Plate tectonics ; Geodesy ; Tectonics ; Earthquake hazard ; Italy ; Croatia
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    BIBLIOGRAFIE SEISMOLOGIE
  • 21
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    Unbekannt
    A combined geophysical/engineering approach for the seismic safety of long-span bridges (2005)
    Springer
    In:  Professional Paper, Perspectives in Modern Seismology, Berlin, Springer, vol. 105, 223 pp., no. 231, pp. 13-30, (ISBN: 3-540-23712-7)
    Details
    Publikationsdatum: 2005
    Schlagwort(e): Earthquake risk ; Site amplification ; Strong motions ; Earthquake engineering, engineering seismology ; Synthetic seismograms ; NOISE ; Nakamura ; Modelling ; Cologne ; DFNK ; Faecke ; Facke
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  • 22
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    The 26 December 2004 Sumatra earthquake and tsunami seen by satellite altimetry and Global Positioning System (2005)
    Springer
    In:  Geo-Information for Disaster Management, Berlin, Heidelberg, New York, Springer, vol. 12, pp. 323-336, (ISBN 3-540-24988-5)
    Details
    Publikationsdatum: 2005
    Schlagwort(e): Textbook of informatics ; Earthquake hazard ; Earthquake risk ; Tsunami(s) ; Proceedings of a conference ; Earthquake ; Indonesia ; Geodesy
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    BIBLIOGRAFIE SEISMOLOGIE
  • 23
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    The Dead Sea fault and its effect on civilization (2005)
    Springer
    In:  Professional Paper, Perspectives in Modern Seismology, Dordrecht, Springer, vol. 65, no. 16, pp. 145-168, (ISBN 0080419208)
    Details
    Publikationsdatum: 2005
    Schlagwort(e): paleo ; Seismicity ; Fault zone ; DSTF ; Seismology ; Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Bucharest ; Romania ; Earthquake risk
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  • 24
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    Velocity field of the Aegean-Anatolian region from 3D finite element models (2005)
    Springer
    In:  Bull., Polar Proj. OP-O3A4, Perspectives in Modern Seismology, London, Springer, vol. 201, no. XVI:, pp. 169-184, (ISBN: 3-540-23712-7)
    Details
    Publikationsdatum: 2005
    Schlagwort(e): Crustal deformation (cf. Earthquake precursor: deformation or strain) ; Geodesy ; Finite Element Method ; Modelling ; Three dimensional ; Seismology ; Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Bucharest ; Romania ; Earthquake risk
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  • 25
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    Unbekannt
    Nonlinear seismology - the seismology of the XXI century (2005)
    Springer
    In:  Bull., Polar Proj. OP-O3A4, Perspectives in Modern Seismology, Dordrecht, Springer, vol. 20, no. 4, pp. 47-65, (ISBN 0080419208)
    Details
    Publikationsdatum: 2005
    Schlagwort(e): Non-linear effects ; Seismology ; Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Bucharest ; Romania ; Earthquake risk
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  • 26
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    An earthquake early warning system for the Romanian capital (2005)
    Springer
    In:  Professional Paper, Open-File Rept., Perspectives in Modern Seismology, Berlin, Springer, vol. 1, no. 16, pp. 1-12, (ISBN 0080419208)
    Details
    Publikationsdatum: 2005
    Schlagwort(e): Review article ; Seismology ; Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Bucharest ; Romania ; Earthquake risk
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  • 27
    Digitale Medien
    Digitale Medien
    Kinetics and mechanism of MnO2 dissolution in H2SO4 in the presence of pyrite (1999)
    Springer
    Journal of applied electrochemistry 29 (1999), S. 191-200 
    Details
    ISSN: 1572-8838
    Schlagwort(e): cyclic redox reaction ; dissolution ; kinetics ; manganese dioxide ; mechanism ; pyrite
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract This paper describes a study of the kinetics and mechanism of MnO2 dissolution in H2SO4 in the presence of pyrite through leaching and electrochemical parameters. Manganese(iv) was found to dissolve mainly through reduction by the ferrous ion generated during oxidation of pyrite by the ferric ion. The oxidation which is slower and rate controlling may proceed through two different reactions, one producing S0 and the other SO42−. Manganese dissolution runs at the same rate as that of pyrite oxidation by maintaining ferrous ion concentration at a much lower level than that of ferric. Kinetic equations based on corrosion coupling principles are developed to explain the observed leaching behaviour.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003490810114
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  • 28
    Digitale Medien
    Digitale Medien
    Molecular structure of trans-[Co(NH3)4(NH2CH3)Cl](ClO4)2 (1998)
    Springer
    Journal of chemical crystallography 28 (1998), S. 69-72 
    Details
    ISSN: 1572-8854
    Schlagwort(e): Co(III) complex ; crystal structure ; kinetics ; steric effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract The title compound crystallizes in the orthorhombic space group Pnma, with a = 7.9209(5), b = 9.818(1), c = 16.867(2) Å, and Z = 4. The structure was solved employing 1864 independent x-ray reflections with I〉2σ(I) by Patterson and difference Fourier techniques and refined by full-matrix least-squares to R = 0.036. The trans-[CO(NH3)4(NH2CH3)Cl](ClO4)2 molecule is on a crystallographic mirror plane. The cobalt ion is in an elongated octahedral coordination with four equatorial ammonia ligands [average Co–N distance equal to 1.966(2) Å], an axial methylamine [Co–N=1.965(3)Å], and an axial chlorine ion [Co–Cl=2.2771(9)Å]. Kinetic steric effects of the complex are interpreted in terms of structural results.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1021786804676
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  • 29
    Digitale Medien
    Digitale Medien
    Sensitivity of PSA process performance to input variables (1995)
    Springer
    Adsorption 1 (1995), S. 133-151 
    Details
    ISSN: 1572-8757
    Schlagwort(e): PSA process ; sensitivity ; equilibria ; kinetics ; heats
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Mathematical models for pressure swing adsorption (PSA) processes essentially require the simultaneous solutions of mass, heat and momentum balance equations for each step of the process using appropriate boundary conditions for the steps. The key model input variables needed for estimating the separation performance of the process are the multicomponent adsorption equilibria, kinetics and heats of adsorption for the system of interest. A very detailed model of an adiabatic Skarstrom PSA cycle for production of high purity methane from a ethylene-methane bulk mixture is developed to study the sensitivity of the process performance to the input variables. The adsorption equilibria are described by the heterogeneous Toth model which accounts for variations of isosteric heats of adsorption of the components with adsorbate loading. A linear driving force model is used to describe the kinetics. The study shows that small errors in the heats of adsorption of the components can severely alter the overall performance of the process (methane recovery and productivity). The adsorptive mass transfer coefficients of the components also must be known fairly accurately in order to obtain precise separation performance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00705001
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  • 30
    Digitale Medien
    Digitale Medien
    Frequency response analysis of a closed diffusion cell with two resonators (1996)
    Springer
    Adsorption 2 (1996), S. 265-277 
    Details
    ISSN: 1572-8757
    Schlagwort(e): frequency response ; diffusion cell ; kinetics ; diffusion ; heat effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract This paper deals with frequency response (FR) analysis of a closed diffusion cell system with two resonators, that is both the LHS and RHS volumes are modulated. The analysis is made for a homogeneous particle described by a single effective diffusivity as well as a biporous pellet described by macropore and micropore diffusions. It is shown that if the perturbation of the volume of the reservoir #2 is lagged behind that of the reservoir #1 by 3π/2, the pressure response in reservoir #1 is significantly enhanced with larger amplitude as well as phase angle. When the perturbations of the two reservoirs are out of phase, the heat effect is reduced and can become insignificant when the two perturbations are completely out of phase (ψ = π). Under such a condition, the pressure difference between the two reservoirs could be doubled. In the case of biporous pellets, it is shown that the FR behaviours obtained for micropore diffusion control and macropore diffusion control are well distinguished. In the former case, the FR system reduces to a traditional batch adsorber one while in the latter case, the FR behaviour is the same as for a two resonator system with homogeneous particles. This difference can be used for the discrimination of micropore and macropore diffusion processes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00879541
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  • 31
    Digitale Medien
    Digitale Medien
    Equilibria and kinetics characterisation of two different structured nutshell-derived activated carbons (1997)
    Springer
    Adsorption 3 (1997), S. 267-275 
    Details
    ISSN: 1572-8757
    Schlagwort(e): characterisation ; equilibria ; kinetics ; micropore size distribution ; n-butane ; nutshell
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Adsorption equilibria and dynamics ofn-butane on two activated carbon samples prepared from the physical activation of nutshell are studied in this paper. The micropore size distribution (MPSD) is considered as the main source of solid heterogeneity. Lennard-Jones' potential theory and Dubinin's theory (TVFM) are used in the equilibria data to derive the MPSD, which is well fitted by a Gamma distribution function. The adsorption energy distribution derived from the MPSD is very asymmetric for both the samples studied, and this energy distribution used in the HMSD/HMSMD kinetics models for the study of adsorption dynamics ofn-butane.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01653629
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  • 32
    Digitale Medien
    Digitale Medien
    Factors affecting bioleaching kinetics of sulfide ores using acidophilic micro-organisms (1999)
    Springer
    BioMetals 12 (1999), S. 1-10 
    Details
    ISSN: 1572-8773
    Schlagwort(e): acidophilic ; strain ; oxidation ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Recovery of metal values from sulfide ores by use of acidophilic microorganisms is gaining importance. A number of commercial/pilot plants are setup to find out the techno-economic feasibility of the overall process. The main drawback in the process is the slow kinetics of dissolution of metal values from the sulfide ores. To make the technology e attractive the kinetics should be improved considerably. There are various factors which determine the overall kinetics such as bacterial activity and concentration, iron and sulfur oxidation, oxygen consumption, reactor design and nature of ore. A brief review has been made dealing with the above parameters
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009228210654
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  • 33
    Digitale Medien
    Digitale Medien
    The dissociation kinetics of H2S over an alumina supported Co-Mo sulphide catalyst (1996)
    Springer
    Catalysis letters 37 (1996), S. 167-172 
    Details
    ISSN: 1572-879X
    Schlagwort(e): dissociation ; kinetics ; Co-Mo sulphide ; H2S
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In this study, a high surface area 4Co∶6Mo∶100γ-Al2O3 sulphide prepared using precipitation from homogeneous solution (PFHS) has been used for the catalytic splitting of hydrogen sulphide into H2 and elemental sulphur. The activity of this new formulation was significantly better than previously reported recipes. Kinetic data collected over a wide range of H2S partial pressures between 883 and 983 K revealed that, although the decomposition followed a first-order law, a mechanism involving H2S adsorption on co-ordinative unsaturation sites of the Co-Mo sulphide catalyst gave a Langmuir-Hinshelwood rate expression that yielded satisfactory model parameters. In particular, the scission of the surface H-S bond appeared to be the rate determining step.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00807749
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  • 34
    Digitale Medien
    Digitale Medien
    Effect of potassium on the high pressure kinetics of ammonia synthesis over fused iron catalyst (1996)
    Springer
    Catalysis letters 37 (1996), S. 173-179 
    Details
    ISSN: 1572-879X
    Schlagwort(e): ammonia synthesis ; iron catalysts ; potassium promotion ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Measurements were performed of reaction rate in the process of ammonia synthesis (T=370–470°C) on doubly promoted (DP) (Al2O3, CaO) and triply promoted (TP) (K2O, Al2O3, CaO) iron catalysts. The latter were obtained by impregnation of the reduced and subsequently passivated DP precursors with alcoholic solution of KOH. The studies were carried out under high total pressure (10 MPa) in a wide range of ammonia partial pressure in the gas phase: from 0.25 to about 7 bar. The results are shown to be authoritative for the so-called kinetic regime. The effect of the presence of K+ cations in the catalyst was the stronger, as the temperature of the reaction was the lower and, in particular, the ammonia pressure in the gas phase the higher. The obtained results are in good accordance with the results of Somorjai's studies on activity of iron single crystal surfaces both clean and covered with (K+O) adlayer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00807750
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  • 35
    Digitale Medien
    Digitale Medien
    Prediction of paper permanence by accelerated aging II. Comparison of the predictions with natural aging results (1996)
    Springer
    Cellulose 3 (1996), S. 269-279 
    Details
    ISSN: 1572-882X
    Schlagwort(e): accelerated tests ; aging tests ; cellulose degradation ; durability ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Accelerated aging tests are credible and useful to predict paper permanence only if such tests can be shown to correlate with natural aging. In the first part of this study, a kinetic model was developed based on the accelerated aging results. In this report, we have shown that this kinetic model can indeed predict the natural aging results of lignin-free sheets with a statistical confidence. This is the first quantitative comparison of accelerated aging with natural aging.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02228806
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  • 36
    Digitale Medien
    Digitale Medien
    Reaction Between Copper Nitrate Hydrate and Methoxydimethyloctylsilane in Methanol (1998)
    Springer
    Journal of solution chemistry 27 (1998), S. 1123-1138 
    Details
    ISSN: 1572-8927
    Schlagwort(e): Sol–gel processing ; hydrolysis ; condensation ; kinetics ; methoxydimethyloctylsilane ; copper nitrate hydrate ; phase diagram
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The reaction rate was determined for copper nitrate hydrate with methoxydimethyloctylsilane (MDOS) in methanol. The rate constants of hydrolysis and condensation were established by quantitative measurement of the product and Karl Fischer water determination. The reaction with the hydrated copper salt resulted in the phase separation of an insoluble product from the reaction mixture. The structure of the product was determined, by Fourier Transform Infrared Spectrometry (FTIR) and Nuclear Magnetic Resonance (NMR) to be a dimer of the MDOS. The results showed the alcohol, producing condensation reaction was negligible in the formation of the dimer. contrary to the case for the well-known reaction by trialkoxysilanes and tetraalkoxysilanes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022662017881
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  • 37
    Digitale Medien
    Digitale Medien
    On the kinetics of degradation of cellulose (1997)
    Springer
    Cellulose 4 (1997), S. 1-5 
    Details
    ISSN: 1572-882X
    Schlagwort(e): paper ; degradation ; ageing ; kinetics ; modelling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1018408515574
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  • 38
    Digitale Medien
    Digitale Medien
    Prediction of paper permanence by accelerated aging I. Kinetic analysis of the aging process (1996)
    Springer
    Cellulose 3 (1996), S. 243-267 
    Details
    ISSN: 1572-882X
    Schlagwort(e): aging tests ; cellulose degradation ; durability ; kinetics ; paper properties
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract The validity of accelerated aging tests to predict and rank papers on their permanence has been under question, preventing the development of performance-based standards for permanent paper. We conducted a general kinetic analysis to investigate the aging process of paper. A general kinetic model is proposed to describe the depolymerization of cellulose. Experimentally it was shown that in the case of aging, cellulose degradation follows classic first-order kinetics as a special case of our general kinetic model. The Arrhenius equation was critically re-examined for the case of a multiple reaction system. It was shown analytically that the Arrhenius equation is still applicable when certain conditions are met. This was convincingly supported by experimental results. We also analysed the dependence of the degradation rate on the moisture content and hydrogen ion concentration. By conducting systematic experiments on these two factors, a general and quantitative relationship was established to explain the contribution of each factor and their interactions. Finally, based on this kinetic analysis, the effects of storage conditions on the life expectancy of paper were estimated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02228805
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  • 39
    Digitale Medien
    Digitale Medien
    Reaction Kinetics for the Anionic Ring-Opening Polymerization of Tetraphenyltetramethylcyclotetrasiloxane Using a Fast Initiator System (1998)
    Springer
    Journal of inorganic and organometallic polymers and materials 8 (1998), S. 111-117 
    Details
    ISSN: 1572-8870
    Schlagwort(e): Organosiloxane ; kinetics ; poly(phenylmethylsiloxane) ; catalyst ; anionic ; ring-opening
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract It is well known that the rate of polymerization for an anionic mechanism is dependent on the ability of the bulk material or solvent system to disassociate the ion pair at the propagating chain end. In the anionic ring-opening polymerization of cyclic organosiloxanes in particular, the larger and softer the counter ion, the more rapidly the reaction proceeds. A recently developed phosphazene initiator system provides a large, soft counter ion relative to other traditional initiators used for the polymerization of poly(dimethylsiloxane) (PDMS). This novel initiator system was used in this investigation for the ring-opening polymerization of tetraphenyltetramethylcyclotetrasiloxane (P4) and the reaction kinetics under bulk and solution conditions were investigated. The new initiator system showed a dramatic increase in the rate of polymerization over the conventional potassium hydroxide-catalyzed system. Furthermore, this initiator was sufficiently reactive to be useful for the ring-opening polymerization of P4 at 293 K.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022487906770
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  • 40
    Digitale Medien
    Digitale Medien
    Degradation of Cellulosic Materials Under the Alkaline Conditions of a Cementitious Repository for Low- and Intermediate-Level Radioactive Waste. II. Degradation Kinetics (1999)
    Springer
    Journal of polymers and the environment 7 (1999), S. 41-51 
    Details
    ISSN: 1572-8900
    Schlagwort(e): Cellulose ; alkaline degradation ; peeling off ; degree of polymerization ; kinetics ; (gluco)isosaccharinic acid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Energietechnik , Maschinenbau
    Notizen: Abstract The degradation of cellulosic materials, differing mainly in the degree of polymerization and the number of reducing end groups, was studied under the alkaline conditions similar to those existing in a cementitious repository for low- and intermediate-level radioactive waste (pH 13.3, T = 25°C). The kinetics of alkaline degradation (peeling-off reaction) were studied and the data analyzed by the model of Haas et al. [13]. The observed kinetic parameters for the propagation reaction and overall stopping reaction were compared with literature data. Although measured under different experimental conditions, literature data and data from this study show a consistent picture. Differences in the extent of degradation observed for the different cellulosic materials could be satisfactorily explained by differences in reducing end group content and, consequently, by differences in the degrees of polymerization. Besides the number of reducing end groups, the degree of amorphousness also plays an important role. The main degradation products formed under the experimental conditions used are α- and β-(gluco)isosaccharinic acid. This is in agreement with many other studies on alkaline degradation of cellulose. The two isomers are formed in roughly equal amounts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1021894102937
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  • 41
    Digitale Medien
    Digitale Medien
    High resolution NMR techniques in catalysis (1998)
    Springer
    Topics in catalysis 5 (1998), S. 133-147 
    Details
    ISSN: 1572-9028
    Schlagwort(e): NMR ; catalysis ; high pressure ; dynamic equilibria ; magnetization transfer ; sapphire tube ; gas phase ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract High resolution NMR techniques are applicable to a variety of aspects of catalysis. Methods for studying homogeneously-catalyzed systems under high gas pressure are described along with approaches for obtaining mechanistic and dynamic information. Many of the same techniques may be applied to heterogeneous catalysis by following the reaction chemistry by gas phase NMR.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019133515789
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  • 42
    Digitale Medien
    Digitale Medien
    Selectivity from a kinetic point of view: nonlinear behavior of logarithmic product ratios as a function of the reciprocal temperature (1998)
    Springer
    Topics in catalysis 5 (1998), S. 159-176 
    Details
    ISSN: 1572-9028
    Schlagwort(e): nonlinear temperature behavior ; Eyring plot ; modified Eyring plot ; selectivity ; selection process ; enantioselectivity ; selection level ; isoinversion principle ; isoinversion temperature ; inversion temperature ; kinetics ; catalysis ; asymmetric hydrogenation ; dihydroxylation ; cocyclization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The influence of the temperature on selectivity is described under special consideration of nonlinearities in the corresponding modified Eyring plots. Reasons for the experimentally well-known behavior are discussed. Furthermore, the conditions for nonlinear temperature behavior are quantified and a concept is described which allows the determination of the temperature dependence of a single reaction pathway in a selection process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019185532627
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  • 43
    Digitale Medien
    Digitale Medien
    Sorption Equilibria and Kinetics of Hydrocarbons onto Activated Carbon Samples Having Different Micropore Size Distributions (1999)
    Springer
    Adsorption 5 (1999), S. 25-37 
    Details
    ISSN: 1572-8757
    Schlagwort(e): micropore size distribution ; activated carbon ; adsorption ; desorption ; equilibrium ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract This paper deals with the prediction of adsorption equilibrium and kinetics of hydrocarbons onto activated carbon samples having different micropore size distribution (MPSD). The microporous structure of activated carbon is characterised by the distribution of slit-shaped micropores, which is assumed to be the sole source of surface heterogeneity. The interaction between adsorbate molecule and pore walls is described by the Lennard-Jones potential theory. Different adsorbates have access to different pore size range of activated carbon due to the size exclusion, a phenomenon could have a significant influence on both multicomponent equilibria and kinetics. Activated carbons with three different MPSDs are studied with ethane and propane as the two model adsorbates. The Heterogeneous Macropore Surface Diffusion model (HMSD) is employed to simulate adsorption kinetics. The simulation results show that the MPSD is an important factor affecting both the multicomponent equilibria and kinetics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1026481704926
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  • 44
    Digitale Medien
    Digitale Medien
    Furfural hydrogenation over carbon‐supported copper (1999)
    Springer
    Catalysis letters 60 (1999), S. 51-57 
    Details
    ISSN: 1572-879X
    Schlagwort(e): furfural hydrogenation ; Cu/carbon catalysts ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Furfural hydrogenation over copper dispersed on three forms of carbon – activated carbon, diamond and graphitized fibers – were studied. Only hydrogenation of the C=O bond to form either furfuryl alcohol or 2‐methyl furan occurred at temperatures from 473 to 573 K. Reduction at 573 K gave the most active catalysts, all three catalysts had activation energies of 16 kcal/mol, and turnover frequencies were 0.018–0.032 s-1 based on the number of Cu0 + Cu+ sites, which were counted by N2O adsorption at 363 K and CO adsorption at 300 K, respectively. The Cu/activated carbon catalyst showed no deactivation during 10 h on stream, in contrast to the other two catalysts. A simple Langmuir–Hinshelwood model invoking two types of sites was able to fit all kinetic data quite satisfactorily, thus it was consistent with the presence of both Cu0 and Cu+ sites.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019090520407
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  • 45
    Digitale Medien
    Digitale Medien
    Study of the ammonia decomposition over iron catalysts (1999)
    Springer
    Catalysis letters 60 (1999), S. 167-171 
    Details
    ISSN: 1572-879X
    Schlagwort(e): ammonia decomposition ; iron catalyst ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The decomposition of ammonia is a reaction associated with the process of the nitriding of metals. The kinetics of the ammonia decomposition on iron catalysts has been studied using a differential reactor with internal mixing. The balance between the inlet and outlet ammonia quantity has been used to determine the degree of conversion. The rate of ammonia decomposition could be described by the following expression: r = k0 exp (Ea/RT)pNH3. The activation energy of the ammonia decomposition process has been found for samples with potassium as E a= 96 kJ/mol, for samples without potassium as E a= 87 kJ/mol.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019007024041
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  • 46
    Digitale Medien
    Digitale Medien
    Pure and Binary Gas Adsorption Equilibria and Kinetics of Methane and Nitrogen on 4A Zeolite by Isotope Exchange Technique (1999)
    Springer
    Adsorption 5 (1999), S. 145-158 
    Details
    ISSN: 1572-8757
    Schlagwort(e): kinetics ; isotope-exchange ; nitrogen ; adsorption ; methane ; zeolite ; equilibria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract The Isotope Exchange Technique (IET) was used to simultaneously measure pure and binary gas adsorption equilibria and kinetics (self-diffusivities) of CH4 and N2 on pelletized 4A zeolite. The experiment was carried out isothermally without disturbing the adsorbed phase. CH4 was selectively adsorbed over N2 by the zeolite because of its higher polarizability. The multi-site Langmuir model described the pure gas and binary adsorption equilibria fairly well at three different temperatures. The selectivity of adsorption of CH4 over N2 increased with increasing pressure at constant gas phase composition and temperature. This curious behavior was caused by the differences in the sizes of the adsorbates. The diffusion of CH4 and N2 into the zeolite was an activated process and the Fickian diffusion model described the uptake of both pure gases and their mixtures. The self-diffusivity of N2 was an order of magnitude larger than that for CH4. The pure gas self-diffusivities for both components were constants over a large range of surface coverages (0 〈 θ 〈 0.5). The self-diffusivities of CH4 and N2 from their binary mixtures were not affected by the presence of each other, compared to their pure gas self-diffusivities at identical surface coverages.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008917308002
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  • 47
    Digitale Medien
    Digitale Medien
    Kinetic studies on oxidation of aromatic donor molecules by horseradish peroxidase and lactoperoxidase (1997)
    Springer
    BioMetals 10 (1997), S. 23-26 
    Details
    ISSN: 1572-8773
    Schlagwort(e): aromatic donor molecules ; horseradish peroxidase ; kinetics ; lactoperoxidase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Based on kinetic evidence, it has been shown for the first time that the mode of binding of aromatic donor molecules is similar in horseradish peroxidase and lactoperoxidase; also that the nature of the heme plays an important role in the reaction with hydrogen peroxide, and has no effect on the reaction of the intermediate compound II with aromatic substrates.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1018310618995
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  • 48
    Digitale Medien
    Digitale Medien
    Partial hydrogenation of benzene to cyclohexene in a continuously operated slurry reactor (1995)
    Springer
    Catalysis letters 31 (1995), S. 431-438 
    Details
    ISSN: 1572-879X
    Schlagwort(e): partial hydrogenation of benzene ; production of cyclohexene ; kinetics ; reaction mechanism ; ruthenium catalyst
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A method has been developed for direct measurement of reaction rates in a continuously operated slurry (CST-) reactor. In contrast to the usual procedure in a two-liquid-phase system the reactor contains only one liquid phase, an aqueous zinc chloride solution in which a ruthenium lanthanoxide catalyst is suspended. The selectivity of benzene hydrogenation with respect to cyclohexene is higher when the new one-liquid-phase procedure is applied. With decreasing degree of benzene conversion the selectivity with respect to cyclohexene approaches 100%. The conclusion is that cyclohexane is formed only by consecutive hydrogenation of cyclohexene.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00808607
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  • 49
    Digitale Medien
    Digitale Medien
    Non-uniform surface kinetics with two types of sites: the case of ethanol oxidation on molybdenum oxide (1996)
    Springer
    Catalysis letters 39 (1996), S. 67-71 
    Details
    ISSN: 1572-879X
    Schlagwort(e): non-uniform surface ; kinetics ; ethanol ; oxidation ; molybdenum oxide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Temkin's theory of rates of catalytic reactions on non-uniform surfaces is extended to the MoO3-catalyzed oxidation of ethanol to acetaldehyde. Two types of sites are assumed to be present, an oxygen atom site that can be modeled with uniform properties and a metal atom site characterized by non-uniform properties both for ethanol chemisorption to an ethoxide intermediate and the conversion of this intermediate to acetaldehyde. The rate-limiting step is the cleavage of a C-H bond in the absorbed ethoxide intermediate. Non-uniform surface kinetics leads to a kinetic rate expression of the form $$v = kP_{C_2 H_5 OH}^{1 - m} P_{O_2 }^{(1 - m)/4} P_{H_2 O}^{ - (1 - m)/2} $$ . Such a rate expression, withm=0.14, is shown to provide a good fit to kinetic data for the selective oxidation of ethanol on a silica supported molybdenum oxide catalyst.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00813732
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  • 50
    Digitale Medien
    Digitale Medien
    Platinum particle size effect on the oxidative dehydrogenation of aqueous ethanol (1996)
    Springer
    Catalysis letters 36 (1996), S. 31-36 
    Details
    ISSN: 1572-879X
    Schlagwort(e): ethanol ; kinetics ; oxidation ; oxydehydrogenation ; platinum ; structure sensitivity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The effect of the platinum particle size was investigated for the catalytic oxidative dehydrogenation of aqueous ethanol to ethanal at a temperature of 303 K, an ethanol concentration of 260 mol m−3, a partial oxygen pressure 60 kPa, a pH of 9, and an ethanal and ethanoate concentration of 20 mol m−3. A particle size effect on the turnover frequency was observed but only for particle sizes smaller than 2 nm. Hence, the reaction shows a limited structure sensitivity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00807202
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  • 51
    Digitale Medien
    Digitale Medien
    Solvent effects in the kinetics of the enantioselective hydrogenation of ethyl pyruvate (1998)
    Springer
    Catalysis letters 55 (1998), S. 73-77 
    Details
    ISSN: 1572-879X
    Schlagwort(e): enantioselectivity ; hydrogenation of ethyl pyruvate ; Pt/alumina catalyst ; solvent effects ; kinetics ; solvent polarity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The influence of solvent on the kinetics of enantioselective hydrogenation of ethyl pyruvate by Pt/Al2O3/dihydrocinchonidine is reported. In a non‐polar solvent, toluene, the reaction is approximately zero order in substrate at constant hydrogen pressure, while under the same conditions and at the same substrate concentration, in the polar solvents ethanol and propylene carbonate the reaction shows a first‐order substrate concentration dependence. Fits to a Michaelis–Menten rate expression show that these differences are the expression of the relative magnitudes of the adsorption term in the rate expression, which in turn reflects the influence of the solvent on the adsorption–desorption processes which take place at the catalyst surface.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019078727850
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  • 52
    Digitale Medien
    Digitale Medien
    The detailed kinetics of the desorption of hydrogen from polycrystalline copper catalysts (1999)
    Springer
    Catalysis letters 59 (1999), S. 143-149 
    Details
    ISSN: 1572-879X
    Schlagwort(e): hydrogen ; desorption ; copper ; activation energy ; kinetics ; order of desorption
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The kinetics of desorption of hydrogen from the copper component of an alumina-supported polycrystalline copper catalyst has been studied in detail by temperature-programmed desorption (TPD). Line-shape analysis of the hydrogen TPD spectra shows: (i) that the desorption is second order, (ii) that the desorption activation energy is in the range 64–68 kJ mol−1 in the coverage range 7–44% of a monolayer, and (iii) that the desorption pre-exponential term has a value ∼10−5 cm2 s−1 atom−1 consistent with the desorption being second order, involving mobile adsorbates and a mobile desorption transition state.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1019080823616
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  • 53
    Digitale Medien
    Digitale Medien
    Improving the performance of the two-rate parameter by use of the integrating ratemeter and temporal optimization (1996)
    Springer
    Microchimica acta 124 (1996), S. 13-25 
    Details
    ISSN: 1436-5073
    Schlagwort(e): kinetics ; rates ; integrating ratemeter ; optimization ; first-order
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The integrating ratemeter is used in concert with the two-rate parameter to form the integrating ratemeter two-rate parameter. Propagation of error theory is applied to the integrating ratemeter two-rate parameter to yield expressions for the precision of rates calculated from the integrating ratemeter two-rate parameter in terms of the precision of the rates measured with the integrating ratemeter. Simulations and experimental results show that in cases where the standard deviation of the rate is relatively constant, the optimum time to make a rate measurement using the integrating ratemeter is also the optimum time to measure either of the rates in the two-rate parameter. If either of the two rates comprising the two-rate parameter is measured at the optimum time, then the precision and accuracy of concentrations measured with this technique are optimized.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01244952
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  • 54
    Digitale Medien
    Digitale Medien
    Transformation kinetics and potential availability of specifically-sorbed phosphate in soils (1998)
    Springer
    Nutrient cycling in agroecosystems 51 (1998), S. 209-215 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Desorption ; kinetics ; microbial transformation ; phosphate ; soils
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The improvement of P management in agriculture and environment requires a good understanding of residual effect of applied P in soils. The specific adsorption of P on variable charge minerals has been considered as the major mechanism that leads to a very low utilization of P fertilizer by crops within a growing season in Chinese red soils. Soil incubation and isotope tracing analysis were carried out to examine the transformation kinetics and potential availability of added specifically sorbed 32P in two pH contrasting light textured soils. The 32P recovered by 0.5 M NaHCO3 extraction and microbial biomass-P measurement from the added specifically sorbed 32P in the soils was well described by a first-order reaction and a Langmuir-type kinetic model, with correlation coefficients (R) being, on average, 0.938 and 0.959, respectively. The half-life (t1/2, from the first-order model) of the four tested mineral-P complexes ranged from 29 to 47 d in the acid sandy soil and 33 to 105 d in the neutral silty soil. Goethite-P was the most stable among the four tested mineral-P complexes. The potential availability of the mineral complex P (q m , in percent of total 32P added) obtained from the Langmuir equation ranged from 43.7 to 90.9% for the four mineral-P complexes, and decreased in the order: Al oxide-P (90.9%) 〉 montmorillonite-P (86.2%) 〉 kaolinite-P (77.5%) 〉 goethite-P (60.2%) in the acid sandy soil, whereas the order was Al oxide-P (89.3%) 〉 kaolinite-P (86.2%) 〉 montmorillonite-P (82.6%) 〉 goethite-P (43.7%) in the neutral silty soil. Based on the release rate and potential availability, kaolinite-P and Al oxide-P could be important sources for residual effect of applied P in variable-charge soils. The goethite-P has the lowest release rate and potential availability among the mineral-P complexes, implying that iron oxides may be the most important variable-charge mineral responsible for P fixation in the Chinese red soils.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009749619865
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  • 55
    Digitale Medien
    Digitale Medien
    Growth of Ordered Domains in a Computer Model Alloy with Lattice Misfit (1999)
    Springer
    Journal of statistical physics 95 (1999), S. 23-43 
    Details
    ISSN: 1572-9613
    Schlagwort(e): model alloy ; Monte Carlo ; elastic interactions ; phase separation ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We study via Monte Carlo simulations the influence of elastic interactions on the ordering and decomposition of a two-dimensional model binary alloy with antiferromagnetic nearest and ferromagnetic next nearest neighbor type interactions following a quench into the coexistence region. The elastic interaction leads to the development of a platelet morphology for the segregated ordered and disordered regions. A length scale characterizing the coarsening process follows a law of the type R=a+bt 1/3 with the growth b decreasing with the amount of ordered phase; this appears to be due to the presence of anti-phase boundaries between neighboring domains ordered on different sublattices which are difficult to eliminate. The application of uniaxial external stress results in “rafting” of the domains. Many of the simulation results are in agreement with experimentally observed effects in nickel-base superalloys.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004569209618
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  • 56
    Digitale Medien
    Digitale Medien
    Effect of concentration and environmental form of tetradecenyl succinic acid on its mineralization in soil (1996)
    Springer
    Biodegradation 7 (1996), S. 377-382 
    Details
    ISSN: 1572-9729
    Schlagwort(e): bioavailability ; builders ; detergents ; kinetics ; mineralization ; sewage sludge ; soil
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Energietechnik , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Tetradecenyl succinic acid (TSA) is the major component of a detergent builder (C12-C14 alkenyl succinic acid), which is inherently biodegradable. 14C-TSA was dosed as a component of sewage sludge into a soil with a history of sludge amendment at final added concentrations of 1.5 and 30 mg (kg soil)-1. In addition, it was dosed to the soil in an aqueous solution to a final added concentration of 30 mg (kg soil)-1. Dose and form were found to have a pronouced effect on the mineralization kinetics. When dosed in a realistic form and concentration (i.e. 1.5 mg (kg soil)-1 as a component of sludge), TSA was mineralized at its highest rate and to its greatest extent, and the mineralization half-life was 2.4 days. When dosed at 30 mg (kg soil)-1 as a component of sludge, mineralization began immediately, and the half-life was 23 days. In contrast, when dosed at this concentration in aqueous solution, the onset of mineralization was preceded by a 13 day lag period and the mineralization half-life was 69 days. Primary biodegradation and mineralization rates of TSA were very similar. Approximately, half the radioactivity was evolved as 14CO2, while the remaining radioactivity became non-extractable, having presumably been incorporated into biomass or natural soil organic matter (humics). This study demonstrated that TSA is effectively removed from sludge-amended soils as a result of biodegradation. Furthermore, it showed the effect that dose form and concentration have on the biodegradation kinetics and the importance of dosing a chemical not only at a relevant concentration but also in the environmental form in which it enters the soil environment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00056421
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  • 57
    Digitale Medien
    Digitale Medien
    Stoichiometry and kinetics of microbial toluene degradation under denitrifying conditions (1995)
    Springer
    Biodegradation 6 (1995), S. 147-156 
    Details
    ISSN: 1572-9729
    Schlagwort(e): bacteria ; degradation ; denitrification ; kinetics ; stoichiometry ; toluene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Energietechnik , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Batch experiments were carried out to investigate the stoichiometry and kinetics of microbial degradation of toluene under denitrifying conditions. The inoculum originated from a mixture of sludges from sewage treatment plants with alternating nitrification and denitrification. The culture was able to degrade toluene under anaerobic conditions in the presence of nitrate, nitrite, nitric oxide, or nitrous oxide. No degradation occurred in the absence of Noxides. The culture was also able to use oxygen, but ferric iron could not be used as an electron acceptor. In experiments with14C-labeled toluene, 34%±8% of the carbon was incorporated into the biomass, while 53%±10% was recovered as14CO2, and 6%±2% remained in the medium as nonvolatile water soluble products. The average consumption of nitrate in experiments, where all the reduced nitrate was recovered as nitrite, was 1.3±0.2 mg of nitrate-N per mg of toluene. This nitrate reduction accounted for 70% of the electrons donated during the oxidation of toluene. When nitrate was reduced to nitrogen gas, the consumption was 0.7±0.2 mg per mg of toluene, accounting for 97% of the donated electrons. Since the ammonia concentration decreased during degradation, dissimilatory reduction of nitrate to ammonia was not the reductive process. The degradation of toluene was modelled by classical Monod kinetics. The maximum specific rate of degradation, k, was estimated to be 0.71 mg toluene per mg of protein per hour, and the Monod saturation constant, K s , to be 0.2 mg toluene/l. The maximum specific growth rate, μ max , was estimated to be 0.1 per hour, and the yield coefficient, Y, was 0.14 mg protein per mg toluene.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00695345
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  • 58
    Digitale Medien
    Digitale Medien
    Biodegradability of diesel oil (1996)
    Springer
    Biodegradation 7 (1996), S. 73-81 
    Details
    ISSN: 1572-9729
    Schlagwort(e): diesel oil ; biodegradation ; CSTR ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Energietechnik , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In batch culture diesel oil was degraded rapidly, with a maximum growth rate (for a consortium of microorganisms) of 0.55 h-1. The corresponding yield Y SX was 0.1 Cmol/Cmol. In a continuous stirred tank reactor the maximum dilution rate was about 0.25 h-1, with a yield of 0.3 Cmol/Cmol. With a residence time of 1 day 82% of the influent oil was degraded. In the batch reactor, of the mixture of linear and branched alkanes the linear alkanes were degraded fastest and with the highest yield. Only after most of the linear alkanes had disappeared were the branched alkanes consumed. In a CSTR a large part of the branched alkanes was not degraded.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00056560
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  • 59
    Digitale Medien
    Digitale Medien
    Invariant kinetic approach to the description of a rock fracture process and induced seismic events (1996)
    Springer
    Pure and applied geophysics 147 (1996), S. 367-375 
    Details
    ISSN: 1420-9136
    Schlagwort(e): Induced seismicity ; kinetics ; rock fracture ; rockburst ; earthquake
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract Powerful seismic events, such as earthquakes and rockbursts, are caused by the accumulation of energy in rocks and loss of rock mass stability. Usually methods of their forecasting are based on the registration of anomalous behavior of geophysical fields. However an efficiency of this approach is low. The present paper proposes a kinetic approach to the description of rock fracture process, which can be used for the forecasting of seismic events and an investigation of structure and energy distributions in rock. 3-D and 1-D kinetic equations describing a process of cluster formation in rock were obtained. The equations are invariant to deformation conditions and to the scale level of events. They showed a good agreement with the results of field observations and laboratory experiments. It was also shown that these equations well describe the processes of earthquake, rockburst and rock sample failure preparation. Catalogues of rockbursts in mines were analyzed with the use of the kinetic equations to find out evidence of induced seismic events. The proposed approach makes it possible to reveal trends in rock behavior and thus predict the rock failure at different scale levels.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00877489
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  • 60
    Digitale Medien
    Digitale Medien
    Bioavailability of a new effervescent tablet of ibuprofen in healthy volunteers (1997)
    Springer
    European journal of clinical pharmacology 52 (1997), S. 505-506 
    Details
    ISSN: 1432-1041
    Schlagwort(e): Key words Ibuprofen; effervescent tablets ; kinetics ; bioavailability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002280050327
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  • 61
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of diphemanil methylsulphate in neonates and in premature infants (1996)
    Springer
    European journal of clinical pharmacology 50 (1996), S. 429-430 
    Details
    ISSN: 1432-1041
    Schlagwort(e): Key words Diphemanil methylsulphate ; Neonate; antimuscarinic agent ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002280050136
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  • 62
    Digitale Medien
    Digitale Medien
    Assessment of inhibition kinetics of the growth of strain P5 on pentachlorophenol under steady-state conditions in a nutristat (1996)
    Springer
    Archives of microbiology 165 (1996), S. 194-200 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Key words Auxostat ; Batch culture ; Chemostat ; Continuous culture ; Fermentation control ; Inhibition ; kinetics ; Nutristat ; On-line measurement ; Pentachlorophenol ; Pollutant ; Sphingomonas ; Steady-state conditions ; Toxicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A bacterium degrading pentachlorophenol (PCP) as the only source of carbon and energy was grown in a “nutristat”, i.e., a continuous culture with on-line measurement and control of the substrate concentration. We improved the PCP nutristat by incorporation of a personal computer with a proportional integral derivative (PID) algorithm for controlling the medium feed pump. The controlled value deviated from the average (set-point) value by 1% maximally. In the PCP nutristat (30°C), the steady-state dilution rate, and hence, specific growth rate, showed a maximum value of 0.142 ± 0.004 h–1 at set-point PCP concentrations between 37 and 168 μM. At PCP concentrations above 168 μM, the steady-state growth rate decreased because of inhibition. The growth yield coefficient was not seriously affected by the PCP concentration, suggesting that uncoupling was not the inhibitory mechanism. It was concluded that the PCP nutristat is very useful for establishing steady-state conditions that maintain growth-inhibitory PCP concentrations and high cell concentrations, conditions for which the chemostat is not suitable.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01692861
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  • 63
    Digitale Medien
    Digitale Medien
    Polymerization kinetics of acrylic bone cements by differential scanning calorimetry (1996)
    Springer
    Journal of thermal analysis and calorimetry 47 (1996), S. 35-49 
    Details
    ISSN: 1572-8943
    Schlagwort(e): bone cement ; DSC ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Bone cements are widely used for the fixation of metallic prostheses in orthopaedics and to form replacements for skull defects in neurosurgery. Acrylic bone cements are based on a mixture of methyl methacrylate (MMA) and a fine powder of polymethyl methacrylate (PMMA). The polymerization of the bone cement occurs in contact with the bone and the prosthesis which act as the boundaries of a bulk polymerization reactor. The kinetic behaviour of the bone cement plays a fundamental role for the final performance of the implant. In this paper, the isothermal and non-isothermal polymerization behaviour of a commercial bone cement is described. A simple phenomenological model, accounting for the autoacceleration ffect, for a diffusion controlled termination mechanism and for the reaction between inhibitor and initiator, is proposed. The reaction kinetics is analysed by DSC. DSC data are used for the determination of the rates of polymerization under isothermal and non-isothermal conditions. The experimental data are processed to calculate the parameters of the proposed phenomenological kinetic model. The analytical and numerical details related to the integration of the model are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01982684
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  • 64
    Digitale Medien
    Digitale Medien
    Erfahrungen mit vier Softwarepaketen für Kinetische Auswertungen in der Thermischen Analyse (1996)
    Springer
    Journal of thermal analysis and calorimetry 47 (1996), S. 543-557 
    Details
    ISSN: 1572-8943
    Schlagwort(e): compensation effect ; DSC ; kinetics ; TG
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Four computer programs as well as one demo-version for non-linear evaluation of kinetic data in thermal analysis and calorimetry, were presented. The multi-task program TA-kin meets all mathematical requirements for solving the numerical assignments. It is shown that the so-called compensation effect is due to the mathematical structure of the Arrhenius equation. Several applications of TA-kin to a lot of DSC- and TG-measurements and isoperibolic batch experiments as well as adiabatic semi batch experiments realized by precision calorimetry have been discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01983996
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  • 65
    Digitale Medien
    Digitale Medien
    Kinetics of the decomposition of calcium carbonate in the presence of Bi2O3 (1996)
    Springer
    Journal of thermal analysis and calorimetry 47 (1996), S. 569-575 
    Details
    ISSN: 1572-8943
    Schlagwort(e): Bi2O3 ; CaCO3 decomposition ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Former studies concerning the formation of the compounds in the pseudobinary systems of Bi2O3-MO type (M =Ca, Sr, Ca+Sr) have shown that the reaction which occurs with the highest rate is that between Bi2O3 and CaO. In the present work CaCO3 was used as CaO source. We carried out an investigation of the thermal decomposition of CaCO3 in the presence of Bi2O3 in comparison with the decomposition of pure CaCO3. The presence of Bi2O3 exerts a complex influence on the CaCO3 decomposition acting on the nucleation as well as on the diffusion of CO2. The decomposition of the samples with low Bi2O3 content follows the mechanism of a contracting sphere. A change from surface nucleation to bulk nucleation is recorded for higher amounts of Bi2O3.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01983998
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  • 66
    Digitale Medien
    Digitale Medien
    Non-enzymatic browning-induced water plasticization (1996)
    Springer
    Journal of thermal analysis and calorimetry 47 (1996), S. 1437-1450 
    Details
    ISSN: 1572-8943
    Schlagwort(e): browning ; crystallization ; glass transition ; kinetics ; milk powder ; water
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract An exotherm, observed in differential scanning calorimetry (DSC) scans of amorphous food materials above their glass transition temperature,T g, may occur due to sugar crystallization, nonenzymatic browning, or both. In the present study, this exothermal phenomenon in initially anhydrous skim milk and lactose-hydrolyzed skim milk was considered to occur due to browning during isothermal holding at various temperatures above the initialT g. The nonenzymatic, Maillard browning reaction produces water that in amorphous foods, may plasticize the material and reduceT g. The assumption was that quantification of formation of water from theT g depression, which should not be observed as a result of crystallization under anhydrous conditions, can be used to determine kinetics of the nonenzymatic browning reaction. The formation of water was found to be substantial, and the amount formed could be quantified from theT g measured after isothermal treatment at various temperatures using DSC. The rate of water formation followed zero-order kinetics, and its temperature dependence well aboveT g was Arrhenius-type. Although water plasticization of the material occurred during the reaction, and there was a dynamic change in the temperature differenceT−T g, the browning reaction was probably diffusioncontrolled in anhydrous skim milk in the vicinity of theT g of lactose. This could be observed from a significant increase in activation energy. The kinetics and temperature dependence of the Maillard reaction in skim milk and lactose-hydrolyzed skim milk were of similar type well above the initialT g. The difference in temperature dependence in theT g region of lactose, but above that of lactose-hydrolyzed skim milk, became significant, as the rate in skim milk, but not in lactose-hydrolyzed skim milk, became diffusion-controlled. The results showed that rates of diffusion-controlled reactions may follow the Williams-Landel-Ferry (WLF) equation, as kinetic restrictions become apparent within amorphous materials in reactions exhibiting high rates at the same temperature under non-diffusion-controlled conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01992838
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  • 67
    Digitale Medien
    Digitale Medien
    Studies on the non-isothermal kinetics of the thermal decomposition of [Cu(NBOCTB)][Cu(NO3)4]· H2O (1997)
    Springer
    Journal of thermal analysis and calorimetry 48 (1997), S. 917-923 
    Details
    ISSN: 1572-8943
    Schlagwort(e): copper compound ; coupled technique ; kinetics ; macrocyclic complex ; non-isothermal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The thermal decomposition process of the complex [Cu(NBOCTB)][Cu(NO3)4] H2O has been studied by TG and DTG technique, and possible intermediates of the thermal decomposition have also been conjectured from the TG and DTG curves. The results suggest that the decomposition of the complex involves five steps: The non-isothermal kinetics of steps 1, 2 and 3 have been studied by means of the Achar and Coats-Redfern method based on TG and DTG curves. Step 1 is a ‘Coring and Growth’ mechanism (n= 1), its kinetic equation may be expressed as: dα/dt=Ae−E/RT(1−α). Steps 2 and 3 are both ‘two order chemical reaction’ mechanisms, their kinetic equations can be expressed as: dα/dt=Ae−E/RT(1−α)2.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01997197
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  • 68
    Digitale Medien
    Digitale Medien
    The thermal degradation kinetics of isomeric poly(dipropyl itaconates) (1997)
    Springer
    Journal of thermal analysis and calorimetry 49 (1997), S. 87-94 
    Details
    ISSN: 1572-8943
    Schlagwort(e): kinetics ; poly(di-propyl itaconates) ; polymer structure ; thermal degradation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Non-isothermal thermogravimetry was performed in a dynamic nitrogen atmosphere, on a series of poly(di-n-propyl itaconates) (PDnPI) and poly(di-iso-propyl itaconates) (PDiPI) which had been prepared in the presence of various amounts of the chain transfer agentn-dodecyl mercaptan (DDM). Differential thermogravimetry (DTG) showed that both polymers degraded in two stages. The DTG curve of PDnPI had a large first peak followed by a smaller shoulder, whereas the DTG curve of PDiPI was composed of two peaks of almost equal heights. The addition of DDM during the polymerisations in both cases resulted in a similar decrease in the relative area of the first peak.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01987424
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  • 69
    Digitale Medien
    Digitale Medien
    Thermooxidative degradation of an unsaturated polyester resin (1997)
    Springer
    Journal of thermal analysis and calorimetry 49 (1997), S. 183-191 
    Details
    ISSN: 1572-8943
    Schlagwort(e): kinetics ; thermooxidative degradation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The results of non-isothermal kinetic analysis of the thermooxidative degradation in air and oxygen of an unsaturated polyester resin are presented. It has been shown that the thermooxidative degradation in oxygen occurs at lower temperatures than the thermooxidative degradation in air. The kinetic parameters of the thermooxidative degradation depend on the heating rate and the oxygen pressure. Two straight lines of InAvs. E (A is the preexponential factor andE is the activation energy), characteristic for the compensation effect, have been obtained for the thermooxidative degradation in air and in oxygen respectively. The difference between the intercepts of these straight lines can be explained by dependence of the pre-exponential factor on the oxygen pressure.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01987438
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  • 70
    Digitale Medien
    Digitale Medien
    Analysis of mesophase formation in side-chain liquid crystalline polycarbosilanes (1996)
    Springer
    Journal of thermal analysis and calorimetry 46 (1996), S. 795-808 
    Details
    ISSN: 1572-8943
    Schlagwort(e): DSC ; kinetics ; liquid crystalline polymer ; optical transmittance ; polycarbosilane ; side-chain mesogen ; transition parameters
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract This paper is concerned with an analysis of the thermodynamics and kinetics of mesophase formation by cooling from the isotropic state of side-chain liquid crystalline polycarbosilanes containing spacers in the range from 3 to 11 CH2-groups. The polymers are characterized by their thermotropic behaviour as far as temperature, enthalpy and entropy of the transitions are concerned. The kinetics was followed by optical and calorimetric methods. Longer spacer length leads to more perfect ordering in the mesophase, higher isotropization temperatures, and lower glass transition temperatures. The Avrami and Ozawa formalism to describe the transition kinetics to the mesophase from the isotropic state cannot be interpreted as the nucleation and growth mechanism known from crystallization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01983603
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  • 71
    Digitale Medien
    Digitale Medien
    Comparative studies on some analytical methods (1997)
    Springer
    Journal of thermal analysis and calorimetry 49 (1997), S. 857-862 
    Details
    ISSN: 1572-8943
    Schlagwort(e): analytical methods ; kinetics ; powder milk ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract This work present comparative results on powder milk storage quality, obtained from analytical methods. Protein content was determined conventional (Kjeldahl) and colorimetric with biuret reagent at 540 nm and integral quality by thermogravimetric and biological methods. A method was developed for the protein separation of powder milk. Powder milk was submitted to degradation processes at 45, 60 and 80°C for 20 days. The results indicated that protein content values were inconsistent if determinations by Kjeldahl and colorimetric methods and biological tests were compared. There is evidence of thermal decomposition of powder milk as detected by biological and thermogravimetric methods.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01996770
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  • 72
    Digitale Medien
    Digitale Medien
    Application of thermogravimetry in the quality control of mebendazole (1997)
    Springer
    Journal of thermal analysis and calorimetry 49 (1997), S. 937-941 
    Details
    ISSN: 1572-8943
    Schlagwort(e): kinetics ; mebendazole ; quality control ; technology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A study was made of the thermal behavior of the starting materials, their mixtures and the resulting mebendazole tablets. The thermal curves were obtained with a Shimadzu thermobalance, model TGA-50, using an air flow of 50 mL min−1 and a heating rate of 10°C min−1 in the temperature interval 30–900°C. The reaction constant velocities for the mebendazole salt and tablets were determined isothermally, using the Arrhenius expression. The thermal stability of mebendazole tablets is lower than that of the mebendazole salt, due to the presence of starch and lactose in the composition. Analysis of the data reveals that thermogravimetry is a powerful tool in pharmaceutical technology and quality control.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01996779
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  • 73
    Digitale Medien
    Digitale Medien
    Kinetic compensation effect in the thermal degradation of polymers (1996)
    Springer
    Journal of thermal analysis and calorimetry 47 (1996), S. 1081-1091 
    Details
    ISSN: 1572-8943
    Schlagwort(e): kinetics ; thermal degradation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The kinetic study of thermal degradation takes into account the validity of the Arrhenius equation. From TG data, the activation energy,E a and pre-exponential factor,A, are evaluated. These results are interpreted by using the ‘kinetic compensation effect’ as basis. A linear correlation between In(A) andE a is obtained in all cases studied. However, in a plot of the logarithm of the rate constant as a function of reciprocal temperature for the same series of reactions, the thermal oxidative degradations of Nylon-6 and PVC display a point of concurrence and one isokinetic temperature, whereas those of HIPS and PC do not. Therefore, in the thermal oxidative degradations of Nylon-6 and PVC a ‘true’ compensation effect occurs, which could be related to the bulk properties of metal oxides, such as different valence states, whereas for other polymers it displays only an ‘apparent’ compensation effect. This means that degradation is largely independent of the bulk properties of oxides, but may be related to the distribution of different kinds of active links in the polymer surface having different activation energies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01979449
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  • 74
    Digitale Medien
    Digitale Medien
    Kinetic analysis of crude oils by a weighted mean activation energy approach (1997)
    Springer
    Journal of thermal analysis and calorimetry 48 (1997), S. 343-348 
    Details
    ISSN: 1572-8943
    Schlagwort(e): activation energy ; combustion ; crude oil ; differential scanning calorimetry ; kinetics ; thermogravimetric analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A weighted mean activation energy method was applied to describe the reactivity and combustibility of crude oils via simultaneous TG/DTG. Thermal experiments were conducted with a non-isothermal method at a heating rate of 10
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01979278
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  • 75
    Digitale Medien
    Digitale Medien
    Kinetics of thermal dehydration and decomposition of Fe(III) chloride hydrate (FeCl3·xH 2O) (1997)
    Springer
    Journal of thermal analysis and calorimetry 48 (1997), S. 385-401 
    Details
    ISSN: 1572-8943
    Schlagwort(e): dehydration and decomposition ; kinetics ; Fe(III) chloride
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Fe(III) chloride hydrate (FeCl3·xH2O) undergoes simultaneous dehydration and dehydrochlorination from its molten phase in the temperature range 100–200
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01979283
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  • 76
    Digitale Medien
    Digitale Medien
    Fermentation alcoolique (1997)
    Springer
    Journal of thermal analysis and calorimetry 48 (1997), S. 413-425 
    Details
    ISSN: 1572-8943
    Schlagwort(e): alcoholic fermentation ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The control of alcoholic fermentation is necessary to obtain a quality wine. The overall dynamic and phenomenological modelling already applied to the simulation of this type of reaction enables us to suggest, in this study, a simple model (of which two variants), are relatively satisfactory. The first variant does not take into account the variation of the ambient temperature; the model translates exactly the first phase of the experimental curve or the moment when highest temperatures are measured. The relaxation phase is less well described because of influence of variation of the ambient temperature is relatively important. The second one considers the system depending on the ambient temperature, the model is correct for the relaxation phase too (the reaction temperature decreases, it nears the ambient temperature). The advantage of this model: It permits one to determine the reaction enthalpy and the kinetic parameters.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01979285
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  • 77
    Digitale Medien
    Digitale Medien
    Thermally stimulated creep study of bismaleimide/carbon fiber composite (1997)
    Springer
    Journal of thermal analysis and calorimetry 48 (1997), S. 623-634 
    Details
    ISSN: 1572-8943
    Schlagwort(e): bismalleimide/carbon fiber composite ; DMA ; kinetics ; TSC
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The correlation between structure/microstructure and thermomechanical properties has been investigated by the Thermally Stimulated Creep (TSC) technique in a high performance thermostable thermoset matrix composite. The high resolving power of this technique allows us to analyse the α retardation mode. The kinetics of molecular movements liberated at the glass transition has been investigated by the technique of fractional loading: the analysis of each elementary process gives the real compliance and the retardation time as a function of temperature. The values of the activation parameters show the existence of a compensation phenomenon which characterizes the microstructure. It also gives access to the loss compliance of the composite material as a function of temperature and frequency. The predictive calculation of loss compliance has been validated by the results obtained by dynamic mechanical analysis (DMA).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01979508
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  • 78
    Digitale Medien
    Digitale Medien
    Einfluß der Sensor-Zeitkonstanten auf die Auswertbarkeit von Ta-Daten (1997)
    Springer
    Journal of thermal analysis and calorimetry 48 (1997), S. 769-782 
    Details
    ISSN: 1572-8943
    Schlagwort(e): kinetics ; non-linear optimization ; reactor time constants ; software ; time constants of sensors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract All temperature sensors have a finitely time constant. The influence of the sensor time constant gts on the results of kinetic evaluation is demonstrated at four reaction types. The ignorance of the sensor indolence gives incorrect activation parameters. Therefore the determination of Τs is necessary. For the estimation of parameters the nonlinear evaluation program TA-kin was used. With its help it is possible to find the real parameters, also when Τs=32 s, if the real Τs-value was entered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01997182
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  • 79
    Digitale Medien
    Digitale Medien
    Kinetic studies on the thermal dissociation of β-cyclodextrin-cinnamyl alcohol inclusion complex (1997)
    Springer
    Journal of thermal analysis and calorimetry 49 (1997), S. 1517-1525 
    Details
    ISSN: 1572-8943
    Schlagwort(e): β-cyclodextrin ; cinnamyl alcohol ; kinetics ; thermal analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The stability of β-cyclodextrin-cinnamyl alcohol inclusion complex (β-CD·C9H10·8H2O) was investigated using TG and DSC. The mass loss took place in three stages: the dehydration occurred between 50–120°C; the dissociation of β-CD·C9H10O occurred in the range of 210–260°C; and the decomposition of β-CD began at 280°C. The dissociation of β-CD·C9H10O was studied by means of thermogravimetry, and the results showed: the dissociation of β-CD·C9H10O was dominated by a two-dimensional diffusion process (D2). The activation energyE was 161.2 kJ mol−1, the pre-exponential factorA was 4.5×1013 min−1. Cyclodextrin is able to form inclusion complexes with a great variety of guest molecules, and the interesting of studies focussed on the energy binding cyclodextrin and the guest molecule. In this paper, β-cyclodextrin-cinnamyl alcohol inclusion complex was studied by fluorescence spectrophotometry and infrared absorption spectroscopy, and the results show: the stable energy of inclusion complexes of β-CD with weakly polar guest molecules consists mainly of Van der Waals interaction.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01983712
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  • 80
    Digitale Medien
    Digitale Medien
    Neural networks for kinetic parameters determination, signal filtering and deconvolution in thermal analysis (1997)
    Springer
    Journal of thermal analysis and calorimetry 49 (1997), S. 1553-1564 
    Details
    ISSN: 1572-8943
    Schlagwort(e): deconvolution ; differential scanning calorimetry ; feedforward neural networks ; kinetics ; signal filtering ; simulations ; thermal analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Feedforward neural networks have been used for kinetic parameters determination and signal filtering in differential scanning calorimetry. The proper learning function was chosen and the network topology was optimized, using an empiric procedure. The learning process was achieved using simulated thermoanalytical curves. The resilient-propagation algorithm have led to the best minimization of the error computed over all the patterns. Relative errors on the thermodynamic and kinetic parameters were evaluated and compared to those obtained with the usual thermal analysis methods (single scan methods). The errors are much lower, especially in presence of noisy signals. Then, our program was adapted to simulate thermal effects with known thermodynamic and kinetic parameters, generated electrically, using a PC computer and an electronic interface on the serial port. These thermal effects have been generated by using an inconel thread.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01983715
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  • 81
    Digitale Medien
    Digitale Medien
    Reaction pathway and kinetics of the thermal decomposition of synthetic brochantite (1997)
    Springer
    Journal of thermal analysis and calorimetry 49 (1997), S. 1467-1475 
    Details
    ISSN: 1572-8943
    Schlagwort(e): CRTA ; DSC ; kinetics ; synthetic brochantite ; TG-DTA ; thermal decomposition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The reaction pathway of the thermal decomposition of synthetic brochantite, Cu4(OH)6SO4, to copper(II) oxide was investigated through the detailed kinetic characterization of the thermal dehydration and desulferation processes. The dehydration process was characterized by dividing into two overlapped kinetic processes with a possible formation of an intermediate compound, Cu4O(OH)4SO4. The dehydrated sample, Cu4O3SO4, was found first to be amorphous by means of XRD, followed by the crystallization to a mixture of CuO and CuO-CuSO4 at around 776 K. The specific surface area and the crystallization behaviour of the amorphous dehydrated compound depend largely on the dehydration conditions. The thermal desulferation process is influenced by the gross diffusion of the gaseous product SO3, which is governed by the advancement of the overall reaction interface from the top surface of the sample particle assemblage to the bottom.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01983705
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  • 82
    Digitale Medien
    Digitale Medien
    Statistical analysis of thermoanalytical experimental data (1997)
    Springer
    Journal of thermal analysis and calorimetry 50 (1997), S. 455-462 
    Details
    ISSN: 1572-8943
    Schlagwort(e): kinetics ; statistical analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A statistical technique based on the Wilcockson criterion is suggested for estimation of the reproducibility of thermoanalytical experiments. Reduction of the whole physicochemical process to a quasi-one-stage process is described.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01980505
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  • 83
    Digitale Medien
    Digitale Medien
    Thermal behaviour and non-isothermal decomposition kinetics of some Nd(III) coordination compounds (1997)
    Springer
    Journal of thermal analysis and calorimetry 50 (1997), S. 425-430 
    Details
    ISSN: 1572-8943
    Schlagwort(e): decomposition ; kinetics ; non-isothermal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The authors present the results concerning the thermal behaviour of three polynuclear coordination compounds of Nd(III) and Co(II) or Fe(III) with triptophan. For the dehydration steps the values of the non-isothermal kinetic parameters have been determined.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01980502
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  • 84
    Digitale Medien
    Digitale Medien
    Thermoxidative Decomposition of Some Polysulfones under Dynamic Conditions of Heating (1998)
    Springer
    Journal of thermal analysis and calorimetry 52 (1998), S. 569-579 
    Details
    ISSN: 1572-8943
    Schlagwort(e): bromomethylated polysulfone ; carboxylated polysulfone ; kinetics ; polysulfone ; thermoxidative decomposition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Kinetic aspects of the first step of thermoxidative decomposition, under dynamic conditions of heating, of some polysulfones have been studied. The dependence of the kinetic parameters on the heating rate and conversion degree has been established. The compensation effect and conversion function have also been discussed. Polysulfone decomposes by the breaking of the main chain, a process involving very high activation energy. Chemically modified polysulfones show the first step of thermoxidative decomposition at relatively low temperatures. This step corresponds to the elimination of functional side - groups for the bromomethylated polysulfone while in the case of the carboxylated polysolfone, the loss of the carboxyl group is probably accompanied by a crosslinking reaction.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010175707790
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  • 85
    Digitale Medien
    Digitale Medien
    Thermal Decomposition of BaC2O4·0.5H2O Studied by Stepwise Isothermal Analysis and Non-Isothermal Thermogravimetry (1998)
    Springer
    Journal of thermal analysis and calorimetry 53 (1998), S. 397-410 
    Details
    ISSN: 1572-8943
    Schlagwort(e): barium oxalate ; kinetics ; non-isothermal thermogravimetry ; stepwise isothermal analysis ; thermal decomposition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Thermal decomposition of BaC2O4·0.5H2O in air was studied by a combination of stepwise isothermal analysis (SIA) and non-isothermal thermogravimetry. The results from both techniques show that the crystal water is released in one step and that anhydrous barium oxalate is decomposed in one step, while BaCO3 decomposes in three steps to BaO, forming two intermediate compounds with the formulas of BaCO3·(BaO)2 and (BaCO3)0.5·(BaO)2.5. Reaction mechanism analyses using the data from SIA measurements show that the controlling mechanism for all the five decomposition steps in isothermal conditions is a two-dimensional phase-boundary controlled process. Kinetic parameters are obtained for the five decomposition steps from the non-isothermal thermogravimetric data.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010124905090
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  • 86
    Digitale Medien
    Digitale Medien
    Obtaining Kinetic Parameters by Modulated Thermogravimetry (1998)
    Springer
    Journal of thermal analysis and calorimetry 54 (1998), S. 695-704 
    Details
    ISSN: 1572-8943
    Schlagwort(e): activation energy ; decomposition ; kinetics ; modulated temperature ; thermogravimetry ; volatilization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A new technique, called modulated thermogravimetry, is introduced as a tool for obtaining continuous kinetic information for decomposition and volatilization reactions. The approach makes use of an oscillatory temperature program to obtain kinetic parameters during a mass loss. MTGA™ may be used under quasi-isothermal conditions to observe a single mass loss or may be combined with linear heating rate or Hi-Res™ controlled rate thermogravimetry to scan from one mass loss region to another. Results obtained are in agreement with those obtained by other kinetic methods.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010171315715
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  • 87
    Digitale Medien
    Digitale Medien
    Kinetic Studies on the Thermal Dissociation of β-Cyclodextrin·Ethyl Benzoate Inclusion Complexes (1998)
    Springer
    Journal of thermal analysis and calorimetry 54 (1998), S. 947-956 
    Details
    ISSN: 1572-8943
    Schlagwort(e): β-cyclodextrin ; ethyl benzoate ; inclusion complex ; kinetics ; thermal decomposition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The stability of β-cyclodextrin·ethyl benzoate·6H2O(β-CD·C6H5COOC2H5·6H2O) was investigated by TG and DSC. The mass loss takes place in three stages: the dehydration occurs at 50-120°C; the dissociation of β-CD·C6H5COOC2H5occurs at 200-260°C; the decomposition of β-CD begins at 280°C. The kinetics of the dissociation of β-CD·C6H5COOC2H5in a dry nitrogen flow was studied by means of thermogravimetry both at constant temperature and linearly increasing temperature. The results show that the dissociation of β-CD·C6H5COOC2H5is dominated by a three-dimensional diffusion process (D3). The activation energy E is 116.19 kJ mol-1and the pre-exponential factor A 6.5358·109min-1. Cyclodextrin is able to form inclusion complexes with a great variety of guest molecules, and the studies focus on the energy of binding between cyclodextrin and the guest molecule. In this paper, the β-cyclodextrin·ethyl benzoate inclusion complex was studied by fluorescence spectrophotometry and infrared absorption spectroscopy, and the results show that the stable energy of inclusion complexes of β-CD with weakly polar guest molecules consists mainly of van der Waals interaction.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010129028436
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  • 88
    Digitale Medien
    Digitale Medien
    Thermal Analysis Studies on Isopropylnitrate (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 9-19 
    Details
    ISSN: 1572-8943
    Schlagwort(e): ARC ; DSC ; HFC ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Isopropylnitrate (IPN) is described as a detonable material used in propellants and explosives. While there is considerable information available on its sensitivity and compatibility with other materials, very little is known about its thermochemical properties. This paper will describe the results obtained from some DSC, heat flux calorimetry (HFC) and accelerating rate calorimetry (ARC) measurements. The ASTM DSC method using a hermetic aluminum pan having a lid with a laser-produced pin hole was used to determine the vapour pressure of IPN1. Results calculated from an Antoine equation are in substantial agreement with those determined from DSC measurements. From the latter measurements, the enthalpy of vaporization was determined to be 35.32±0.62 kJ mol−1. Attempts to determine vapour pressures above about 0.8 MPa resulted in significant decomposition of IPNg. The enthalpy change for decomposition in sealed glass systems was found to be -3.43±0.09 kJ g−1 and -3.85±0.03 kJ g−1, respectively from DSC and HFC measurements on IPN1 samples loaded in air. Slightly larger exotherms were observed for the HFC results in air than those in inert gas, suggesting some oxidation occurs. In contrast, no significant difference in the observed onset temperature of about 150°C was observed for both the HFC and ARC results. From DSC measurements, an Arrhenius activation energy for decomposition of 126±4 kJ mol−1 was found. These measurements were also conducted in sealed glass systems and decomposition appeared to proceed primarily from the liquid phase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010190829563
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  • 89
    Digitale Medien
    Digitale Medien
    Kinetics of Thermal Decomposition of Mixed Ligand Trinuclear Compound of Cadmium(II) (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 233-241 
    Details
    ISSN: 1572-8943
    Schlagwort(e): cadmium(II) atom ; kinetics ; non-isothermal decomposition ; Schiff-base compound
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The crystal C81H78N12O6Cd3 was synthesized and its structure was determined by single crystal X-ray diffraction method. The complex crystallizes in the monoclinic system space group P21/n with cell parameters, a=15.959(4) Å, b=26.222(3) Å, c=25.907(6) Å, β=101.60(2)°. The non-isothermal kinetics of the crystal was studied by use of non-isothermal TG and DTG curves. The kinetic parameters were analyzed by means of integral and differential methods, and mechanism functions of the thermal decomposition reaction for its second step were proposed. The kinetic equation of thermal decomposition is expressed as: dα/dt=Aexp(-E/RT)1.5(1-α)4/3[1/(1-α)1/3-1]−1. The average values of E(kJ mol−1) and lnA/s−1 are 339.25, 43.95, respectively.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010117113150
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  • 90
    Digitale Medien
    Digitale Medien
    Re-examination of the Kinetics of the Thermal Dehydroxylation of Goethite (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 301-309 
    Details
    ISSN: 1572-8943
    Schlagwort(e): dehydroxylation ; goethite ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The kinetics of thermal dehydroxylation of aluminuous goethites [1] synthesised from a ferrous salt has been re-examined using the general reaction order kinetic law. The utilised data processing was based on the procedures employed by dissolution kinetics. Recalculation of the activation energies EA of the dehydroxylation yielded the values 130, 132, 128, and 123 kJ mol−1 for pure goethite, goethite with 10, 20, and 30 mol% Al substitution, respectively. The values of EA are in a good agreement with those given for goethite in literature. The EA values are linearly related with the chemically bound excess H2O/OH− in the crystal lattice that is apparently influenced by Al substitution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010181416785
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  • 91
    Digitale Medien
    Digitale Medien
    Thermogravimetric Analysis of Cobalt(II)-dothiepin Complexes (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 841-849 
    Details
    ISSN: 1572-8943
    Schlagwort(e): cobalt(II)-dothiepin ; kinetics ; TG
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The complexes of cobalt(II) with dothiepin (DOT) hydrochloride have been studied for kinetics of thermal degradation by thermogravimetric analysis (TG) and derivative thermogravimetric studies (DTG) in a static nitrogen atmosphere at a heating rate of 10° C min−1. A general mechanism of thermal decomposition is advanced involving dehydration and decomposition process for both organic and inorganic ligands. The thermal degradation reactions were found to proceed in three steps having an activation energy in the range 6.75–170 kJ mol−1. Thermal decomposition kinetics parameters were computed on the basis of thermal decomposition data.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010181716727
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  • 92
    Digitale Medien
    Digitale Medien
    Gegeneration of Deactivated β-Zeolite by Coke Oxidation (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 297-303 
    Details
    ISSN: 1572-8943
    Schlagwort(e): β-zeolite ; coke ; cumene ; kinetics ; regeneration ; TG
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract An accurate description of coke burn off is obtained from a catalyst based on β-zeolite and used for benzene alkylation with propylene giving cumene by using the thermogravimetric technique. A simple empirical kinetic model was successfully applied to interpolate the data of thermogravimetric analysis performed on samples after partial burn off. Different temperatures, partial pressures of oxygen and gas flow rates were the variables studied in order to calculate the apparent rates and the activation energy for the coke oxidation reaction and to outline the best conditions for the industrial regeneration procedure of our proprietary catalyst PBE-1 for cumene synthesis. Combining the unusually long lifetime per reaction cycle with the optimized regeneration procedure leads to an outstanding overall catalyst life.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010178029977
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  • 93
    Digitale Medien
    Digitale Medien
    Non-Isothermal Pyrolysis and Kinetics of Oil Shales (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 953-958 
    Details
    ISSN: 1572-8943
    Schlagwort(e): differential scanning calorimeter ; kinetics ; oil shale ; pyrolysis ; thermogravimetry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In this research, non-isothermal pyrolysis behavior and kinetics of three oil shales were studied by thermal analysis methods. All the thermal effects were endothermic and no exothermic region was observed in DSC curves. When oil shales are heated in nitrogen atmosphere in TG/DTG, two different mechanisms causing loss of mass were observed. The region between ambient temperature and 500 K was distillation. The second mechanism was visbreaking and cracking and it was observed between the region 500 and 800 K. Kinetic parameters of all the samples are determined by Coats and Redfern method and the results are discussed with regard to their accuracy and the ease of interpretation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010107701483
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  • 94
    Digitale Medien
    Digitale Medien
    Pre-Eutectic Densification of Calcium Carbonate Doped with Lithium Carbonate (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1461-1473 
    Details
    ISSN: 1572-8943
    Schlagwort(e): CaCO3 ; densification ; kinetics ; Li2CO3
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Pressureless sintering of CaCO3 was carried out, with Li2CO3 (from 0.5 to 8 wt%) as an additive, under different pressures of CO2. Densification occurs between 600 and 700°C. Sintering above the eutectic temperature (T〉662°C) leads to the decomposition of calcium carbonate and the materials become expanded. At 620° under 1 kPa of CO2, a relative density of 96% is reached. Li2CO3 enhances the densification process and grain growth of calcium carbonate. CO2 pressure slows down densification and grain growth kinetics. These results are explained by the influence of carbonate and calcium ion vacancies on the sintering mechanisms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010191414628
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  • 95
    Digitale Medien
    Digitale Medien
    Thermal Behaviour and Decomposition Kinetics for Two Palladium(II) Complexes with 1-aminopyrene and its Derivative (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 383-391 
    Details
    ISSN: 1572-8943
    Schlagwort(e): 1-aminopyrene (apyr) ; N-(2-pyridylmethylene)-1-pyrenylamine (pmpa) ; kinetics ; palladium(II)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The thermal decomposition studies for two palladium(II) complexes Pd(apyr)2Cl2 and Pd(pmpa)Cl2 (apyr=1−aminopyrene and pmpa=N−(2−pyridylmethylene)−1−pyrenylamine) were carried out in pure nitrogen using TG-DTG techniques. The non-isothermal kinetic parameters for the two complexes were evaluated employing the method suggested by Málek, Šesták, Koga et al. Based on the above results, thermal behaviour of the complexes were carefully discussed, which showed that not only the parameters value, but also the decomposition pattern and mechanism for complex 1 are different from complex 2.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010159322866
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  • 96
    Digitale Medien
    Digitale Medien
    Studies on the Kinetics of the First Order Autocatalytic Decomposition Reaction of Highly Nitrated Nitrocellulose (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 403-411 
    Details
    ISSN: 1572-8943
    Schlagwort(e): first order autocatalytic reaction ; HNNC ; kinetics ; TG
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The kinetics of the first order autocatalytic decomposition reaction of highly nitrated nitrocellulose (HNNC, 14.14%N) was studied by using thermogravimetry (TG). The results show that the TG curve for the initial 50% of mass-loss of HNNC can be described by the first order autocatalytic equation $$\frac{{{\text{d}}y}} {{dt}} = - 10^{16.4} \exp \left( { - \frac{{210380}} {{RT}}} \right)y - 10^{16.7} \exp \left( { - \frac{{171205}} {{RT}}} \right)y(1 - y)$$ and that for the latter 50% mass-loss of HNNC described by the reaction equations $$\frac{{dy}} {{dy}} = - 10^{16.3} \exp \left( { - \frac{{169483}} {{RT}}} \right)y\quad (n = 1)$$ and $$\frac{{dy}} {{dt}} = - 10^{16.8} \exp \left( { - \frac{{165597}} {{RT}}} \right)y^{2.61} \quad (n \ne 1)$$
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010163423775
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  • 97
    Digitale Medien
    Digitale Medien
    Positronium Conversion Reactions for Testing the Electron Delocalization in 3d Complexes Caused by Ligands (1998)
    Springer
    Structural chemistry 9 (1998), S. 389-394 
    Details
    ISSN: 1572-9001
    Schlagwort(e): Positronium chemistry ; kinetics ; spin exchange reactions ; paramagnetic 3d complexes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The rate constants of ortho- into para-positronium conversion reactions promoted by paramagnetic 3d complexes were found to be linearly correlated with the delocalization, β of unpaired metal electrons caused by ligands. It is shown here that βs, usually obtained by UV/Vis absorption spectroscopy, may also be deduced from the correlations mentioned above.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022459813247
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  • 98
    Digitale Medien
    Digitale Medien
    Mechanism and kinetics of inorganic sulphates decomposition (1997)
    Springer
    Journal of thermal analysis and calorimetry 49 (1997), S. 1227-1241 
    Details
    ISSN: 1572-8943
    Schlagwort(e): inorganic sulphates ; kinetics ; mechanism ; thermodynamics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Thermal decomposition of different inorganic sulphates are presented. A number of techniques, but mainly TG and DTA, are used to prove the mechanism and kinetics of CaSO4, BaSO4, FeSO4·xH2O, Al2(SO4)3·xH2O under various gas atmospheres. It is shown how the partial pressure of gas components and heating rate may effect the mechanism and kinetic parameters. There are also examples on the effects of some additives and initial treatment on the thermal processes. On the base of the results obtained some recommendations are given concerning the precautions to be taken into account in the thermal decomposition studies and the sulphur recovering.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01983679
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  • 99
    Digitale Medien
    Digitale Medien
    Influence of the particle size distribution on the CRTA curves for the solid-state reactions of interface shrinkage type (1997)
    Springer
    Journal of thermal analysis and calorimetry 49 (1997), S. 1477-1484 
    Details
    ISSN: 1572-8943
    Schlagwort(e): CRTA ; kinetics ; particle size distribution ; rate jump method
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The kinetic curves at infinite temperature for the solid-state reactions of the interface shrinkage type were drawn theoretically by taking account the particle size distribution in the sample mixture. The CRTA curves for the reactions with the particle size distribution can be drawn by utilizing the universal kinetic curves at infinite temperature. The proper kinetic treatment for the CRTA curves with the particle size distribution is discussed in connection with the property of the kinetic equation with respect to the particle size distribution. The present kinetic consideration is taken as a simulation for the reactions with a certain distribution in α among the reactant particles, produced preferably by the mass and heat transfer phenomena during the thermoanalytical measurements. The merit of the rate jump method by a single cyclic CRTA curve is also discussed on the basis of the present results.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01983706
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Low/high temperature relationships in dinitramide salts by DEA/DSC and study of oxidation of aluminum powders by DSC/TG (1997)
    Springer
    Journal of thermal analysis and calorimetry 49 (1997), S. 1161-1170 
    Details
    ISSN: 1572-8943
    Schlagwort(e): basicity ; dinitramides ; kinetics ; oxidation ; tanδ ; transition temperatures
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The dinitramide salts of ammonia (ADN), hexamethylenetetramine (HDN), potassium (KDN), and sodium (NaDN) showed a linear relationship between the DSC rate of decomposition at the peak maximum and the DEA tanδ value at the low temperature transition peak. As the cation basicity increased in the series ADN〈HDN〈KDN〈NaDN, there was an increase in the low temperature transition peak, the energy barrier for relaxation, and the decomposition peak temperature, and a decrease in the tanδ value at the low temperature transition peak, specific heat capacity, and the rate and enthalpy of decomposition. The more basic salts were more thermally stable (i.e., higher decomposition temperature) and less energetic (i.e., lower enthalpy of decomposition). The more internal free volume (disorder) present in these salts, the higher the rates of relaxation and decomposition. Five aluminum powders of different surface areas were analyzed by DSC in platinum sample pans, and it was found that the enthalpy and rate of oxidation increased as the particle size of Al decreased while the enthalpy of the Al melt decreased. TG showed a two-step weight gain in the oxidation of Al with plateaus in the 650 and 1130°C regions and the percent weight gain increased as the particle size of Al decreased. Variable DSC and TG heating rate studies showed that the activation energies for the first step in the oxidation process increased as the particle size of Al increased.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01983671
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