Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 82 (1999), S. 0 
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The wear resistance of four Al2O3/SiC nanocomposites that contained SiC particles of varying average size (40, 200, and 800 nm) was studied under dry sliding conditions and compared with the results obtained in unreinforced alumina. The wear rate of the alumina and the nanocomposites of equivalent grain size increased as the contact load increased; however, the nanocomposite wear resistance at high contact loads was better than that of the alumina by a factor of 3–5. The wear resistance of the nanocomposites of submicrometer grain size was fairly independent of the contact load, and their wear resistance at high contact loads was up to two orders of magnitude better than that of the alumina. The mechanisms responsible for these behaviors were discussed in terms of the microscopic wear mechanisms that were observed on the worn surfaces.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1438-2385
    Keywords: Lactococci ; Proteolysis ; Flavour development ; Cheese-curd slurries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract This study describes the accelerating effect exerted on proteolysis and flavour development in cheese-curd slurries by combined application ofLactococcus lactis subsp.lactis IFPL359 and high concentrations of its Lac− Prt− derivative, (i.e. that which has reduced capacity to metabolize lactose and reduced proteolytic activity, strain T1). Cells of strain T1 partially lysed by either sonication or incubation with lysozyme, were also used to ascertain how proteolysis was affected by release of intracellular enzymes in the initial stage of incubation of the strains in cheese-curd slurries. The presence of strain T1 produced higher levels of non-protein nitrogen (NPN) and amine nitrogen (AN) during the first weeks of incubation when partially lysed cells had been added. Addition of whole cells of strain T1 produced higher values of NPN and AN at the end of incubation of slurries, accelerating proteolysis by about 2 weeks with respect to the control, which only contained the parental strain IFPL359. At the end of the experimental period higher amino acid levels were detected by HPLC in the slurry containing whole T1 cells. Volatile fractions of the different cheese-curd slurries were also analysed. The higher level of proteolysis produced by addition of high levels of strain T1 appeared to be related to release of intracellular enzymes by this strain owing to its greater capacity for autolysis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 10 (1997), S. 49-54 
    ISSN: 0894-3230
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: ---Various diallyl- and allylpropargylamines were pyrolyzed in a stirred-flow reactor at temperatures in the range of 330-500°C, pressures of 8-16 Torr and residence times of 0·4-2·4 s using toluene as carrier gas. The reaction products were propene, allene and aldimines. The allene to propene ratio changed considerably with the third substituent on the N atom. At conversions in the range 13-55%, the consumption of the amines showed first-order kinetics. The following Arrhenius parameters [A (s-1) and Ea (kJ mol-1)] were obtained from the rate coefficients: diallyl-tert-butylamine, log  A = 10·32 ± 0·12, Ea = 139 ± 2; diallylneopentylamine, log A = 12·87 ± 0·26, Ea = 168 ± 3; allylpropargyl-tert-butylamine, log A = 10·23 ± 0·18, Ea = 126 ± 2; allylpropargyltosylamine, log A = 13·05 ± 0.36, Ea = 197 ± 5; and allylpropargylphenylamine, log A = 12·10 ± 0·35, Ea = 162 ± 4. Polar, six-center cyclic transition states are suggested for the elimination of propene and allene, via non-concerted bond breaking-bond forming mechanisms. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 11 (1998), S. 407-410 
    ISSN: 0894-3230
    Keywords: gas-phase thermolysis ; N-methyl-N-phenyl-tert-butylsulfenamide ; morpholinyl-tert-butylsulfenamide ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: N-Methyl-N-phenyl-tert-butylsulfenamide (MPSA) and morpholinyl-tert-butylsulfenamide (MOSA) were thermolyzed in a stirred-flow reactor at temperatures of 340-390 °C and pressures of 7-13 Torr, using toluene as carrier gas, at residence times of 0.3-1.3 s. Isobutene was formed in 99% yield through first-order reactions having the following Arrhenius parameters (A,s-1, Ea, kJ mol-1): MPSA, log A  =  12.41 ± 0.02, Ea  =  158.8 ± 0.2; MOSA, log A  =  12.91 ± 0.22, Ea  =  159 ± 3. It is proposed that the elimination of isobutene takes place by unimolecular reaction mechanisms involving polar, four-center cyclic transition states, forming S-unsubstituted thiohydroxylamines as co-products. Thermochemical parameters, estimated by semiempirical AM1 calculations, are reported for the latter and for the parent molecules. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0044-8249
    Keywords: Komplexe mit Schwefelliganden ; ortho-Metallierung ; Palladiumverbindungen ; Sulfoxide ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0570-0833
    Keywords: complexes with sulfur ligands ; ortho-metalation ; palladium compounds ; sulfoxides ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 28 (1996), S. 353-359 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The amide derivatives of t-butylsulfenic acid mentioned in the title have been thermolyzed in a stirred-flow reactor at temperatures of 273-390°C and pressures of 7-15 torr, using toluene as carrier gas, at residence times of 0.4-2 s. Isobutene formed in 95-99% yields, through order one reactions, following the Arrhenius equations: N, N-dimethyl t-butylsulfenamide: $$k(s^{-1})=10^{14.45\pm 0.46}\exp(-175\pm 5 {\rm kJ/mol}\,{\bf RT})$$ 2,6-dimethylpiperidyl t-butylsulfenamide: $$k(s^{-1})=10^{14.38\pm 0.26}\exp(-161\pm 3 {\rm kJ/mol}\,{\bf RT})$$ N-t-butyl t-butylsulfenamide: $$k(s^{-1})=10^{14.75\pm 0.37}\exp(-184\pm 7 {\rm kJ/mol}\,{\bf RT})$$These thermolyses are considered to take place through unimolecular, four-center cyclic transition-state reaction mechanisms, giving rise to isobutene plus the corresponding S-unsubstituted thiohydroxylamines. The latter decompose outside the reactor at temperatures above -78°C forming free sulfur and dimethylamine, 2,6-dimethylpiperidine, and t-butylamine, respectively. © 1996 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 27 (1995), S. 99-108 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title amines were pyrolyzed in a stirred-flow reactor at 380-510°C, pressures of 8-15 torr and residence times of 0.3-2.4 s, using toluene as carrier gas. The substrates with an allyl group yielded propene and iminonitriles as reaction products. HCN is formed by decomposition of the iminonitriles. The first-order rate coefficients for propene formation fit the Arrhenius equations Allyl cyanomethyl amine:\documentclass{article} \pagestyle{empty} \begin{document} $$ k({\rm s}^{ - {\rm 1}}) = 10^{13.29 \pm 0.35} {\rm exp(} - {\rm 189} \pm 5{\rm kJ/mol }RT{\rm)} $$ \end{document}Diallyl cyanomethyl amine:\documentclass{article} \pagestyle{empty} \begin{document} $$ k({\rm s}^{ - {\rm 1}}) = 10^{13.00 \pm 0.20} {\rm exp(} - {\rm 183} \pm 3{\rm kJ/mol }RT{\rm)} $$ \end{document} Diethyl cyanomethyl amine gave a 20:1 gas mixture of ehylene and ethane, plus HCN. The liquid product fraction contained mainly N-ethyl methanaldimine. The first-order rate coefficients for ethylene formation followed the Arrhenius equation \documentclass{article}\pagestyle{empty}\begin{document}$$ k({\rm s}^{ - {\rm 1}}) = 10^{15.30 \pm 0.24} {\rm exp(} - {\rm 226} \pm 3{\rm kJ/mol }RT{\rm)} $$\end{document} Diethyl propargyl amine decomposed cleanly into allene and N-ethyl ethanaldimine. The first-order rate coefficients for allene formation fit the Arrhenius equation \documentclass{article}\pagestyle{empty}\begin{document}$$ k({\rm s}^{ - {\rm 1}}) = 10^{12.84 \pm 0.30} {\rm exp(} - {\rm 168} \pm 4{\rm kJ/mol }RT{\rm)} $$\end{document} The results suggest that the above allyl and propargyl amines decompose unimolecularly by mechanisms involving six-center cyclic transition states. For diethyl cyanomethyl amine, a nonchain free radical mechanism is proposed. © 1995 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 30 (1998), S. 451-456 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-cyanomethyl-N-ethyl aniline (CEAN) and N-cyanomethyl-N-ethyl-p-anisidine (CEPA) have been thermolyzed in a stirred-flow reactor, in the range of 510-560 °C, pressures of 7-11 torr and residence times of 0.5-0.9 s, using toluene as carrier gas. N-cyanomethyl-N-ethyl-p-nitroaniline (ECNA) was thermolyzed at 640°C and 13% conversion. Ethylene and HCN formed in 43% yield each as products from all three starting materials. Phenyl methanaldimine and p-anisidyl methanaldimine were also products of CEAN and CEPA, respectively. The consumption of CEAN and CEPA showed first-order kinetics for a three-fold increase of reactant inflow and initial conversions of up to 40 percent. The following Arrhenius equations were obtained from the rate coefficients for the production of ethylene: CEAN: k=1015.10±0.74 exp(-238±11 kJ/mol·RT); CEPA: k=1015.61±0.29 exp(-246±4 kJ/mol·RT). The results are explained by means of radical, nonchain thermolysis mechanisms. The thermochemistry of relevant reaction steps has been estimated from thermochemical parameters calculated by using the semiempirical AM1 method. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet: 30: 451-456, 1998
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...