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  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 11 (1965), S. 268-273 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The motion of individual air bubbles in a water stream flowing turbulently in a 4 in. × 4 in. vertical conduit is investigated by photographic means. The bulk water velocity ranges from 40.8 to 267 cm./sec., corresponding to a system Reynolds number range of 48,600 to 386,000. Both tap and demineralized water were used at or near room temperatures. Air bubbles range from 0.038 to 0.70 cm. in equivalent radius and the corresponding bubble Reynolds number based on relative velocity ranges from 58 to 4,500.The results indicated that the bubble relative velocity in a turbulent water stream is similar to the rise velocity of single bubbles through a quiescent liquid. It was found to be practically independent of the system Reynolds number for bubbles having an equivalent radius above 0.3 cm. Large fluctuations in the bubble velocities were noted in all cases. The drag coefficient is, in general, lower for the demineralized water tests than for tap water when the bubble Reynolds number is below 2,000. Above this value, a mergence of the drag coefficients for all tests occur with a peak of approximately 2.0 at a bubble Reynolds number of 3,000, which is lower than the nonflow value of 2.6.
    Additional Material: 9 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 11 (1965), S. 825-831 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Analytical solutions were obtained for temperature distributions in a single adiabatic fuel cell with heat generation by TΔS, I2R, and polarization. With these results it is possible to characterize heat transfer in a battery with convection in the fuel and air streams, and with conduction of heat in three directions, by means of an average temperature for which an analytical solution was also obtained. Although the temperature can be kept within safe limits in low-power density batteries, the results show that critical dimensions exist beyond which failure by thermal buckling will occur.
    Additional Material: 7 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 40 (1994), S. 1498-1514 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mathematical tools necessary to describe quantitatively the chemical processes that dictate the performance of exhaust oxygen sensors are developed. Such sensors are used commonly to monitor exhaust streams generated by internal-combustion processes. Calculated results compare well with available experimental results, although several open questions are idetified that require more experimental data. The mathematical formalism for describing the transport of gaseous species through the porous spinel structure protecting the platinum electrode on the exhaust side of the sensor is developed based on the Stefan-Maxwell equations. The kinetic processes occurring at the interface formed by the platinum electrode and the spinel structure, including the oxidation of hydrogen and carbon monoxide and various adsorption-desorption reactions, enter as boundary conditions for the transport equations. The analysis enables one to calculate the sensor's voltage response as a function of the air-to-fuel ratio λ and to investigate phenomena such as the magnitude of the voltage jump in going from rich to lean gas mixtures and the λ value at which this jump occurs.
    Additional Material: 9 Ill.
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  • 4
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The sequences of synthetically prepared methylphosphonate oligodeoxyribonucleotides have been verified using ionspray tandem mass spectrometry with sample introduction via flow injection. The technique involves the use of product-ion scans from multiply protonated (4+ and 5+) precursors. Among the ions detected are several series of fragments of different charge states that indicate the base sequence of the intact molecule. Oligomers as large as 18 bases have been successfully characterized.
    Additional Material: 4 Ill.
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  • 5
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry has been used to measure accurately the molecular masses of synthetic methylphosphonate oligodeoxyribonucleotides, up to 18 nucleotides in length. A simple method has been developed for the complete sequence verification of these compounds, which are intractable by classical means. Sequencing from the 5′ end of the molecule is possible because of inefficiencies in the synthetic procedure. Complementary information from the 3′ end can be obtained by partial hydrolysis of the methylphosphonate backbone.
    Additional Material: 5 Ill.
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  • 6
    ISSN: 0899-0042
    Keywords: chirality ; fluoxetine ; norfluoxetine ; desipramine ; iprindole ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The antidepressant fluoxetine (FLU) and its N-demethylated metabolite, norfluoxetine (NFLU), each contains a chiral center. The combination of FLU and desipramine (DMI), another antidepressant, has been reported to be useful in treatment of depression, to dramatically increase plasma levels of DMI and also to produce more rapid β-adrenergic receptor down-regulation in brain than caused by DMI alone. We have now begun studies on the effects of this drug combination on the levels of FLU and NFLU enantiomers in the rat. In addition, the combination of FLU and iprindole (IPR) was also investigated. Male Sprague-Dawley rats were treated intraperitoneally with either normal saline vehicle, DMI (5 mg/kg/day), (R,S)-FLU (10 mg/kg/day) or DMI (5 mg/kg/day) + (R,S)-FLU (10 mg/kg/day) for 4 days. Following the last treatment, 24 h urine samples were collected. Rats were sacrificed and brains were removed. For the IPR study, rats were pretreated with either saline or IPR-HCl (11.2 mg/kg) and then treated 1 h later with (R,S)-FLU. After 5 h, the rats were sacrificed and brains were removed. Brain and urine samples were analyzed by gas chromatography with electron-capture detection for free (R)- and (S)-FLU and (R)- and (S)-NFLU after extraction and reaction with (-)-(S)-N-(trifluoroacetyl)prolyl chloride. The results from the brains of the rats treated with DMI/FLU indicate that levels of the enantiomers of both FLU and NFLU were significantly increased over those seen in the animals receiving (R,S)-FLU alone. In the IPR/FLU treated rats, an increase in the brain levels of both (R)- and (S)-FLU was noted when compared with rats receiving (R,S)-FLU alone; however, there appeared to be no increase in the brain levels of NFLU enantiomers. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 181 (1990), S. 1-22 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Das Pfropfen von 2-(Dimethylamino)ethyl methacrylat (DMAEMA) auf lineares Polyethylen niedriger Dichte (LLDPE) in der Schmelze wurde mittels Messungen des Monomerumsatzes, des Pfropfgrades und der Pfropfeffizienz untersucht. Die Ergebnisse zeigen, daß das Pfropfen von DMAEMA auf LLDPE bereits bei niedrigen Temperaturen von etwa 90°C in der Schmelze durchgeführt werden kann, obwohl der Schmelzpunkt von LLDPE bei etwa 120°C liegt. Wenn die Pfropfreaktion bei zu hohen oder zu niedrigen Temperaturen durchgeführt wird, kann nur ein sehr niedriger Pfropfgrad beobachtet werden. Hohe Reaktionstemperaturen begünstigen die Polymervernetzung, was sich im Absinken des Schmelzindex bemerkbar macht. Die meisten Pfropfvorgänge werden während der Anfangsphase der Reaktion (unter den vorliegenden Bedingungen während der ersten 3 min) beobachtet. Eine Verlängerung der Reaktionsdauer über diesen Zeitraum hinaus führt zu verstärkter Vernetzung und erhöhter Produktion des Homopolymeren, was die Effizienz des Prozesses verringert. Organische Peroxide sind über einen weiten Halbwertszeitenbereich effektive Initiatoren der Pfropfreaktion, während Azoinitiatoren keine Pfropfung bewirken.
    Notes: Grafting of 2-(dimethylamino)ethyl methacrylate (DMAEMA) on linear low density polyethylene (LLDPE) in the melt has been studied through measurements of monomer conversion, the degree of grafting and the grafting efficiency. Results show that the grafting of DMAEMA on LLDPE can be carried out in the melt at temperatures as low as 90°C even though the melting point of the LLDPE is as high as 120°C. When the grafting reaction is carried out at too low or too high temperature, a low degree of grafting is observed. High reaction temperature favoured crosslinking of the polymer as indicated by decreasing melt flow index. Most of the grafts were obtained during the early period of the reaction (before 3 min under the reaction conditions used). Further increase in reaction time increased crosslinking and also produced more homopolymer, thus decreasing the grafting efficiency. Organic peroxides are effective initiators for the grafting reaction over a broad range of half-lives while azo initiators do not produce grafting.
    Additional Material: 12 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 15 (1994), S. 1459-1465 
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: An updated human heart protein two-dimensional electrophoresis (2-DE) database is presented. The database, which contains some 1388 protein spots characterised in terms of Mr and pI, has been analysed further by Western immunoblotting and protein sequencing. From a total of 103 protein spots analysed, 49 have been identified by immunoblotting and 32 have been identified by protein sequencing. A further six proteins have tentatively been assigned by comparison with the human heart 2-DE protein database of Jungblut et al. (Electrophoresis) 1994, 15, 685-607). This database is being used in studies of alterations in protein expression in the diseased and transplanted human heart.
    Additional Material: 1 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 22 (1994), S. 167-170 
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A new method for the determination of N/Ti ratio for TiNx samples has been proposed. High energy resolution Auger spectra recorded of the Ti L3M23M45 peak have shown that on nitridation of Ti to TiNx a second peak, labelled the L3M23Hybrid peak, emerges at 3.9 eV below the L3M23M45 peak in the raw data, which grows with the grade of nitridation. After a simple Shirley background correction a linear dependence between the ratio of the L3M23Hybrid/L3M23M45 peak height of the raw data and the N/Ti ratio was found. This relation can be used directly to evaluate the nitrogen content of an unknown TiNx compound by recording only the Ti L3M23M45 region. The changes of the L3M23M45 peak structure have been interpreted and compared with earlier DOS calculations for Ti and TiN. Good agreement between experiment and theory was found, enabling a discussion of the valence electronic structure changes for Ti on nitridation.
    Additional Material: 4 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 20 (1993), S. 589-594 
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The fracture surface of a spray-formed Al-5.2Cr-1.4Zr alloy has been examined using AES and scanning Auger microscopy (SAM). Cratered regions of the surface were identified and high-energy resolution AES analysis showed a localized 20 Å thick Al2O3 film to be present in these areas. Chemical-state imaging of the Al fracture surface enabled the local distribution of oxide to be determined. The surface topography was not found to be suppressed using the standard (P—B)/B or (P—B)/(P + B) correction algorithms. This point is discussed with consideration of the electron emission from such highly structured surfaces. The oxide thickness measured from the craters is in good agreement with that previously determined by XPS for powder particles produced in the atomization process. Crater formation is suggested to occur as a result of complete powder particle solidification prior to the particles impacting the substrate/deposit. The localized oxide, revealed by fracture, presents areas of weakness in the unworked material.
    Additional Material: 5 Ill.
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