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  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 14 (1968), S. 866-869 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A study was made to evaluate pulses as a forcing function on a 24-plate distillation column. Pulses of two shapes, rectangular and displaced cosines, and of different widths were used as inputs to the reflux return line from the condenser to the column. The effect of the disturbance was a change in the liquid return rate which correspond to the shape and size of the pulse. The output responses of the system were temperatures measured at different times and at different plates in the column.Bode diagrams were plotted from the experimentally determined data. From these plots, it was determined that the system could be approximated by linear first-order equatons. The time constants for the linear system were determined both by direct sinusoidal forcing and by pulse forcing. Pulse data were considered acceptable when the values of the time constant and the phase angle determined by the pulse compared favorably with those determined by steady state sinusoidal forcing.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 5 (1959), S. 502-505 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pure liquids were evaporated in a wetted-wall column into flowing streams of air to investigate the thickness and transfer resistance of gas films.It was found necessary to express Reynolds number relative to the liquid surface to correlate transfer with gas flow.Laminar and buffer layers in the gas phase were calculated from fluid-flow principles and compared to the effective film thickness calculated from mass transfer and molecular diffusivity. Good agreement was obtained, indicating applicability of fluid mechanics to mass transfer problems.Eddy diffusivity was indicated to have a negligible effect upon the total resistance to transfer. Consequently it might be concluded that in packed towers where distances in the turbulent phase are shorter transfer between phases depends almost entirely upon molecular diffusivity.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 12 (1966), S. 603-604 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 15 (1969), S. 480-480 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 1141-1148 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal structure of N-acetyl-L-4-hydroxyproline (Hyp) was determined by direct methods. (The crystal is orthorhombic with the space group P212121.) The acetyl group is in the trans conformation and the pyrrolidine ring puckers at Cγ (CsCγ envelope), as in most Hyp residues. According to the rotation angle ψ = -30°, the N-acetyl-L-4Hyp has the same conformation as an α-helix of prolyl residues. The crystal packing is stabilized by hydrogen bonds between three different molecules and the same molecule of water. One of the water bridges involves the carbonyl of the N-acetyl group of one molecule and the hydrogen atom of the 4-OH group of another. Such an arrangement has been proposed to explain the high stability of (Gly-L-Pro-L-4Hyp)n. A second bridge involves the two hydrogens of the water molecule and the carbonyl groups of two neighbouring molecules, as already proposed in a dihydrated model of collagen. These experimental features, which are discussed in relation to the different models of collagen, allow us to propose an hypothetical arrangement for the water molecule which is strongly retained in the triple helix of (Gly-L-Pro-L-4Hyp)n.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 33 (1992), S. 297-302 
    ISSN: 1040-452X
    Keywords: Light exposure ; Implantation rate ; IVF ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Mature mouse oocytes were exposed prior to in vitro fertilization to visible light during 1, 2, or 4 hr at an intensity of 4,000 lux. Compared to controls cultured under identical conditions but protected from light, exposed eggs did not show any significant modification of cleavage speed are rate. After transfer of blastocysts obtained in vitro in uteri of pseudopregnant females, the implantation rate and the proportion of normal fetuses were not found to be different in relation to preliminary light exposure of oocytes fertilized and cultured in vitro. © 1992 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 13 (1986), S. 223-230 
    ISSN: 0148-7280
    Keywords: oocytes ; acidification ; CO2 ; in vitro fertilization ; preimplantation development ; mouse ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effects of varying pH levels on superovulated mouse oocytes before in vitro fertilization, culture, and transfer were investigated. Mouse oocytes acidified for 1 hour with 20% CO2 (pH 6.9) exhibited a wide range of alterations. Five hours after insemination, 25% of these eggs showed different degrees of cytolysis and their perivitelline space contained numerous spermatozoa. At 12 hours normal-looking eggs from this group showed a higher proportion of polypronuclear zygotes than the control group (exposed, 51%; controls, 18%). Acidification thus markedly increased the permeability of the zona pellucida and/or interfered with the normal block to polyspermy. Fewer eggs achieved the two-cell stage among groups submitted to acidotic pH levels (6.9 to 6.6). In contrast, alkaline conditions (pH 7.8) did not reduce the proportion of two-cell embryos. However, only eggs maintained at pH 7.5 were capable of producing 80% of blastocysts. In other groups developmental blockage occurred mainly between stages 2 and 4. A significant reduction was found in the proportion of recipient females becoming pregnant after intrauterine transfer of blastocysts originating from CO2-treated oocytes. This difference might be related to the existence of a large polyploid population among experimental eggs.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 5 (1973), S. 61-66 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel type of interannular coupling (6JH,F = 1.0 to 1.3 Hz) has been observed in some fluorodinitrodiphenyl ethers between the fluorine(s) on one ring ortho to the ether linkage and a proton ortho to it on the other ring. 1H and 19F chemical shift and coupling constant data support the previous conclusion that these ethers preferentially adopt a twist (propeller) conformation. On account of the geometrical disposition of the six bonds between the interacting nuclei and the latter's spatial proximity in this conformation, direct coupling through-space is indicated. Concerted libration around the ether bonds brings about magnetic equivalence of the o-fluoro substituents on one ring and causes equal coupling to be observed to the o-proton on the other ring. The possiblity that the coupling is mediated by an intervening π-cloud is suggested as an alternate mechanism for indirect coupling. The observed interannular transmission of spin information provides evidence in favor of a recent proposal made concerning the mode of action of the thyroid hormones.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 3 (1971), S. 255-257 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The PMR spectra of mytilitol at 60, 100 and 220 MHz are presented; the latter confirms the structure 1.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Assignment of all 13C chemical shifts of perezone (1) and some derivatives was possible using time averaged 25·15 MHz spectra with the aid of proton noise modulated and CW decoupling. Rapid interconversion of tautomeric forms of 2,5-dihydroxy-1,4-benzoquinones is deduced from the 13C spectra.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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