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  • 1
    Electronic Resource
    Electronic Resource
    Application of Secondary Nucleation Theory to Semirigid Macromolecules: PEEK, PET, and PEN (1995)
    s.l. : American Chemical Society
    Macromolecules 28 (1995), S. 7744-7755 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00127a022
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  • 2
    Electronic Resource
    Electronic Resource
    Reduction of free-space-loss for good and rapid 3D path planning of 6DOF robots (1995)
    Springer
    Journal of intelligent and robotic systems 13 (1995), S. 263-278 
    Details
    ISSN: 1573-0409
    Keywords: Path planning ; collision detection ; robot modelling ; graph searching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper deals with a new approach to solve the up to 6DOF robots global collision-free path planning. This problem seems to be more difficult when big or very long pieces are manipulated in cluttered and occupied environments. Moreover, the computational effort increases if the necessary path resolution is very high. The developed algorithm is based on the c-space technique. Different robot models are used for rapid c-spaces computation. Each one for different parts of a typical pick and place task. The algorithm selectively uses these global or local c-spaces. This strategy leads to fast global c-space computation without a considerable loss of free-space caused by the simplified robot model, and to quasi real-time local c-space computation. The paths searching in the computed c-spaces can be performed by several techniques: cell (cube) mapping, octree, and slice, which are rule-base selected in an adequate way. Finally, the results of the algorithm implementation in several real robots are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01424010
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  • 3
    Electronic Resource
    Electronic Resource
    Pinus pollen in the atmosphere of Vigo and its relationship to meteorological factors (2000)
    Springer
    International journal of biometeorology 43 (2000), S. 147-153 
    Details
    ISSN: 1432-1254
    Keywords: Key words Airborne pollen ; Correlations ; Meteorological factors ; Pinus ; Pollen concentrations ; Pollinosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract  The Pinus genus has an elevated pollen production and an anemophilous nature. Although considered to be hypoallergenic, numerous cases of allergies caused by Pinus pollen have been cited and different authors believe that its allergenicity should be studied in more depth. In the city of Vigo several patients have tested positive for Pinus pollen extracts in skin tests, some of them being mono-sensitive to such pollens. In order to ascertain the behaviour of Pinus pollen and its correlation to the main meteorological factors, we carried out an aerobiological study in the city of Vigo from 1995 to 1998 by using a Hirst active-impact volumetric sporetrap, model Lanzoni VPPS 2000, placed on the left bank of the Vigo estuary (42°14’15’’N, 8°43’30’’W). Pinus has high quantitative importance in the airborne pollen spectrum of the city. It is one of the best represented taxa constituting 13%–20% of the total annual pollen levels. The quantity of Pinus pollen present in the atmosphere of the city of Vigo throughout a year is 5751 grains (as the average for the sampled years), with a very long pollination period, from the middle of January until May. The maximum concentration was recorded in 1998 with 1105 grains/m3 on 3 March, a much greater value than those for the previous years. At the end of its pollination period there is usually a final increase in Pinus pollen concentrations coinciding with the pollination of Pinus silvestris, which are more abundant in mountainous areas far from the city.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004840050001
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  • 4
    Electronic Resource
    Electronic Resource
    Determination of iron, copper and zinc in tinned mussels by inductively coupled plasma atomic emission spectrometry (ICP-AES) (1994)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 348 (1994), S. 390-395 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An optimisation of the ICP-AES determination of Fe, Cu and Zn in tinned mussels has been carried out. The optimum conditions for the radio frequency power, peristaltic pump flow, plasma gas flow, nebuliser gas pressure, auxiliary gas flow and observation height above load coil were determined manually for each element, since the Simplex method was less adequate. Scans were carried out with the aim of finding the most sensitive spectral lines, whose intensity did not always coincide with literature data. Limits of detection, linearity, precision, and accuracy were also investigated. The possible spectral interferences due to Na, K, Ca, Mg, P, I and nitric acid were studied from three different points of view and the results did not agree. The influence of the matrix on the determination of the above elements in tinned food from the Galician Rias (in the south coast of Galicia) was also studied. The results obtained were comparable to those obtained by AAS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00323141
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  • 5
    Electronic Resource
    Electronic Resource
    Crystallization and structure-mechanical property relations in poly(aryl ether ether ketone) [PEEK] (1990)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 30 (1990), S. 860-869 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In the development of advanced composite materials, the mechanical behavior of the matrix is of critical importance. The next generation of composite materials will be based on high modulus tough matrices, of which poly(aryl ether ether ketone) [hereinafter, referred to as PEEK] is one of the first crystalline thermoplastics to receive serious attention. As in all crystalline polymers, the matrix is itself a composite material whose properties depend significantly on the crystalline morphology developed during processing. In this contribution, the current understanding of crystallization in PEEK and its influence on mechanical properties is reviewed. Problems yet to be resolved are highlighted.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760301409
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  • 6
    Electronic Resource
    Electronic Resource
    Polarographic study of a benzodiazepinooxazole: Cloxazolam (1989)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 334 (1989), S. 158-161 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The polarographic behaviour of 10-chloro-11b-(2-chlorophenyl)-2,3,7,11b-tetrahydrooxazolo[3,2-d][1,4]-benzodiazipine-6(5H)-one (cloxazolam) was studied in the pH range 1–12. Cloxazolam suffers a hydrolysis process, which can be followed by polarography. The reduction processes of cloxazolam and its hydrolysis product are irreversible and their currents are diffusion-controlled. Two polarographic methods have been developed upon the basis of the reduction of both the protonated iminium form (pH 1.45, measurement time: 10 min) and the benzophenone produced in the hydrolysis process (pH 11.75, measurement time: 15 min). The relationship between reduction peak current and concentration is linear up to at least 5.72×10−5 mol/l for both methods. A higher sensitivity was obtained for the method based on the benzophenone reduction (detection limit 5.72×10−8 mol/l; 20 ppb). The methods developed were applied to the determination of cloxazolam in its pharmaceutical formulations (Betavel, 1 mg). The method in alkaline medium was the most adequate for the determination of the compound in tablets, with errors lower than 1%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00476678
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  • 7
    Electronic Resource
    Electronic Resource
    Electroanalytical study of a benzodiazepinooxazole: Mexazolam (1993)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 345 (1993), S. 451-455 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The electroanalytical behaviour of 10-chloro-11b-(2-chlorophenyl)-2,3,7,11b-tetrahydrooxazolo[3,2-d][1,4]-benzodiazepin-6(5H)-one (Mexazolam) was studied in the pH-range 1–13. The compound suffers a hydrolysis process, which can be followed by voltammetric techniques. The reduction process of Mexazolam is irreversible in the whole pH range 1–13 studied; the cathodic reactions of its hydrolysis products are irreversible at pH values lower than 7 and reversible in neutral and alkaline media at a scan rate range of 0.1–40 V·s−1. The electrode process attributed to the reduction of the carbonyl group is predominantly adsorption-controlled and the reduction of the iminium group of the different species of Mexazolam is diffusion-controlled. A differential pulse polarographic method has been developed upon the basis of the reduction of the protonated iminium form. The relationship between reduction peak current and concentration is linear up to at least 13 ppm. The reproducibility of the method in terms of relative standard deviation (RSD) was smaller than 1.6% for ten determinations, at a concentration level of 5.51×10−6 and 2.62×10−5 mol/l. A determination limit of 80 ppb was obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00325625
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  • 8
    Electronic Resource
    Electronic Resource
    Electroanalytical study of benzodiazepinooxazoles: Haloxazolam (1990)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 336 (1990), S. 672-675 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The polarographic behaviour of 10-bromo-11 b-(2-fluorophenyl)-2,3,7,11 b-tetrahydrooxazolo [3,2-d][1,4] benzodiazepin-6(5H)-one (Haloxazolam) was studied in the pH range 1–13. Haloxazolam suffers a hydrolysis process, which can be followed by polarography. The reduction processes of Haloxazolam and its hydrolysis products are irreversible and their currents are diffusion-controlled. This behaviour was compared with that observed for other members of benzodiazepinooxazoles. Two polarographic methods have been developed upon the basis of the reduction of both the protonated iminium form (0.05 mol/l HCl, measurement time: 5 min) and the benzophenone produced in the hydrolysis process (pH 13.25, measurement time: 17 min). The relationship between reduction peak current and concentration is linear up to at least 6.62×10−5 mol/l for both methods. A higher sensitivity was obtained for the method based on the benzophenone reduction (detection limit 1.06×10−7 mol/l; 40 μg/l). The reproducibility of the both methods in terms of relative standard deviation was inferior to 2%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331413
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  • 9
    Electronic Resource
    Electronic Resource
    Triple melting behavior of poly(ethylene terephthalate co-1,4-cyclohexylene dimethylene terephthalate) random copolyesters (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 763-781 
    Details
    ISSN: 0887-6266
    Keywords: random copolyesters ; copolymers ; crystallization ; melting ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The melting behavior of poly(ethylene terephthalate co-1,4-cyclohexylene dimethylene terephthalate) [PET/CT] random copolyesters has been studied. The basis of this analysis was the triple melting behavior of PET homopolymers, which is commonly observed after a period of isothermal crystallization followed by linear heating in a differential scanning calorimeter. Both ET and CT homopolymers are able to crystallize, and as a consequence, the copolymer morphology depends on the ET/CT ratio. It has been reported that at low CT concentrations, the ET units can crystallize with complete rejection of the CT units and that at high CT concentrations, the CT units can cocrystallize with the ET units. In the present work, low CT concentrations were selected, as they are completely rejected from the ET crystals. The purpose was to further test the hypothesis that in the triple melting behavior of PET homopolymers, the second DSC melting endotherm is related to secondary species crystallized by material rejected from the primary crystals. This concept arose from our previous work, where it was speculated that increasing the average molecular-weight of PET would enhance molecular entanglement and increase secondary crystallization. This process would give rise to a higher amount of species being rejected from the main crystals, i.e., an increase of secondary crystallization would occur, and as a consequence the second melting endotherm would be enhanced. Similar to the effect of molecular weight, such behavior has been observed as a function of rejected copolymer content. This gives support to our previously proposed step-like crystallization and melting mechanism for PET homopolymers, and has the potential to be extended to other high temperature semicrystalline polymeric systems. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 763-781, 1998
    Additional Material: 26 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    The triple melting behavior of poly(ethylene terephthalate): Molecular weight effects (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 1757-1774 
    Details
    ISSN: 0887-6266
    Keywords: polyesters ; crystallization ; melting ; morphology ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The melting behavior of isothermally crystallized PET has been studied using linear heating in a differential scanning calorimeter (DSC). Variables such as crystallization temperature, crystallization time, heating rate, and average molecular weight are the main focus of the study. On the basis of several experimental techniques, a correlation of the melting behavior of PET with the amount of secondary crystallization was found to exist. It was observed that the triple melting of PET is a function of programmable DSC variables such as crystallization temperature, crystallization time, and heating rate. However, in testing the hypothesis that there was a correlation between melting endotherms and secondary crystallization inside spherulites, it was found necessary to use a DSC-independent variable in order to enhance the observed effects. Therefore, on the basis of a crystallization model that involves secondary branching along the edges of parent lamellar structures, it was speculated that an increase in the average molecular weight could affect the triple melting of PET due to an increase of rejected portions of the macromolecules. It was found that the second melting endotherm increased, apparently, at the expense of the third one as the average molecular weight was increased. The second melting endotherm was also found to correlate proportionally with the amount of secondary crystallization inside spherulites. The results support a model of crystallization which basically consists of parent crystals and at least one population of secondary, probably metastable, crystals. This latter structural component must involve excluded portions of the macromolecules that did not crystallize during the isothermal crystallization period of the parent crystals. An increase of molecular weight gives rise to a higher entanglement density which in turn increases the fraction of initially rejected chain sections and therefore the amount of secondary crystallization. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1757-1774, 1997
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
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