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31.
P. Koenig und Wilhelm Müller 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1936,71(2):121-137
Zusammenfassung Die Konservierung von Tabakfabrikaten, um sie vor dem Muffigwerden und Verschimmeln sowie vor der Gärung (Kautabak) zu schützen, dürfte so alt sein wie die Tabakfabrikation selbst; namentlich gilt dies für den Kautabak, der sich früher einer viel weiter gehenden Verwendung erfreute als heute. Eine eingehende Bearbeitung hat das Problem der Tabakkonservierung (physikalisch und chemisch) bisher noch nicht erfahren.Die Versuche erstreckten sich nur auf die Konservierung mit chemischen Mitteln. Durch Umfrage in der Tabakindustrie wurden die hier gebräuchlichen Mittel festgestellt.Die Versuche bringen zunächst einen Vergleich der Konservierungsmittel auf einem Agar-Nährboden. Bei ihrer Prüfung auf Tabak (Tabakfabrikate zu Rauchzwecken) wurden Schnittbreite, Menge und Zusammensetzung der Soßierung, Beschaffenheit des Tabaks und Wassergehalt berücksichtigt.Aus der Bewertung der geprüften Konservierungsmittel für ihre Eignung zur Schimmelverhütung auf Rauchtabak ergibt sich die folgende abnehmende Reihenfolge hinsichtlich der wirksamen Zusatzmengen: Chinosol, Ester der p-Oxybenzoesäure und deren Natriumsalze (als Handelspräparate unter den Namen Solbrol, Nipagin, Nipasol usw. erhältlich), Benzoesäure, Natriumbenzoat. Die in der Reihenfolge nun folgenden Mittel, nämlich Salicylsäure, Natriumformiat und Borsäure halten wir infolge ihrer verhältnismäßig geringen konservierenden Wirkung auf Tabak für nicht geeignet.Andere Eigenschaften der Mittel, z. B. ihre praktische Verarbeitungsmöglichkeit und etwaige Beeinflussung des Tabaks, sind hierbei nicht berücksichtigt.Die Versuche sollen vorerst nur die Brauchbarkeit bestimmter chemischer Stoffe als Konservierungsmittel für Tabak zeigen; sie lassen dagegen die Frage der von den näheren Umständen abhängigen Notwendigkeit der Anwendung eines Konservierungsmittels bei den einzelnen Tabakerzeugnissen unberührt. 相似文献
32.
Ravindranath G. Naick Wilhelm Pritzkow Jürgen Rasche 《Advanced Synthesis \u0026amp; Catalysis》1977,319(5):785-789
On the Autoxidation of Bicyclo[2,2,2]octene During the autoxidation of bicyclo[2,2,2]octene at 90°C about 50% of epoxide are obtained. The most important byproduct obviously is a polymeric peroxide. From the acidic products formed in low amounts, cis-1, 4-Cyclohexane dicarboxylic acid could be isolated as the corresponding dimethyl ester. 相似文献
33.
34.
Influence of Microstructure and Surface Activation of Dual‐Phase Membrane Ce0.8Gd0.2O2−δ–FeCo2O4 on Oxygen Permeation 下载免费PDF全文
Madhumidha Ramasamy Stefan Baumann Justinas Palisaitis Falk Schulze‐Küppers Maria Balaguer Daejin Kim Wilhelm A. Meulenberg Jochim Mayer Ramesh Bhave Olivier Guillon Martin Bram 《Journal of the American Ceramic Society》2016,99(1):349-355
Dual‐phase oxygen transport membranes are fast‐growing research interest for application in oxyfuel combustion process. One such potential candidate is CGO‐FCO (60 wt% Ce0.8Gd0.2O2?δ–40 wt% FeCo2O4) identified to provide good oxygen permeation flux with substantial stability in harsh atmosphere. Dense CGO‐FCO membranes of 1 mm thickness were fabricated by sintering dry pellets pressed from powders synthesized by one‐pot method (modified Pechini process) at 1200°C for 10 h. Microstructure analysis indicates presence of a third orthorhombic perovskite phase in the sintered composite. It was also identified that the spinel phase tends to form an oxygen deficient phase at the grain boundary of spinel and CGO phases. Surface exchange limitation of the membranes was overcome by La0.6Sr0.4Co0.2Fe0.8O3?δ (LSCF) porous layer coating over the composite. The oxygen permeation flux of the CGO‐FCO screen printed with a porous layer of 10 μm thick LSCF is 0.11 mL/cm2 per minute at 850°C with argon as sweep and air as feed gas at the rates of 50 and 250 mL/min. 相似文献
35.
Rubber materials filled with reinforcing fillers display nonlinear rheological behavior at small strain amplitudes below γ0 < 0.1. Nevertheless, rheological data are analyzed mostly in terms of linear parameters, such as shear moduli (G′, G″), which loose their physical meaning in the nonlinear regime. In this work styrene butadiene rubber filled with carbon black (CB) under large amplitude oscillatory shear (LAOS) is analyzed in terms of the nonlinear parameter I3/1. Three different CB grades are used and the filler load is varied between 0 and 70 phr. It is found that I3/1(φ) is most sensitive to changes of the total accessible filler surface area at low strain amplitudes (γ0 = 0.32). The addition of up to 70 phr CB leads to an increase of I3/1(φ) by a factor of more than ten. The influence of the measurement temperature on I3/1 is pronounced for CB levels above the percolation threshold.
36.
Sedi Helsper Wesam A. Hatem Lisa Young Zane Wilhelm Matthew W. Liberatore 《Journal of the American Oil Chemists' Society》2022,99(7):613-619
Demand for biodiesel has increased due to being a more environmentally-friendly fuel. Cold weather operation of biodiesel is challenging due to fatty acid methyl ester (FAME) content in biodiesel. Saturated FAMEs crystallize at relatively high temperatures, increase the viscosity of biodiesel, and can clog fuel lines. Here, several factors altered crystallization temperature (CT) of FAMEs, including composition, shear rate, and cooling rate. The crystallization of pure and binary mixtures of methyl palmitate, methyl myristate, and methyl stearate were studied under shear flow and static conditions. Static phase CTs of pure methyl palmitate, methyl myristate, and methyl stearate were 26, 14, and 35°C, respectively. In binary mixtures, CTs were depressed up to 7°C, which agreed with freezing point depression theory. Increasing shear rate up to 100 s−1 decreased CT by 2°C compared to static conditions. Decreasing cooling rate from 1 to 0.1°C/min increased CT less than 2°C. Overall, FAME composition altered CT more than shear flow or cooling rate for pure and binary mixtures of three FAMEs. 相似文献
37.
Jyothilakshmi Vadassery Michael Reichelt Guillermo H. Jimenez-Aleman Wilhelm Boland Axel Mithöfer 《Journal of chemical ecology》2014,40(7):676-686
The majority of plant defenses against insect herbivores are coordinated by jasmonate (jasmonic acid, JA; (+)-7-iso-jasmonoyl-L-isoleucine, JA-Ile)-dependent signaling cascades. Insect feeding and mimicking herbivory by application of oral secretions (OS) from the insect induced both cytosolic Ca2+ and jasmonate-phytohormone elevation in plants. Here it is shown that in Arabidopsis thaliana upon treatment with OS from lepidopteran Spodoptera littoralis larvae, the antibiotic neomycin selectively blocked the accumulation of OS-induced Ca2+ elevation and level of the bioactive JA-Ile, in contrast to JA level. Furthermore, neomycin treatment affected the downstream expression of JA-Ile-responsive genes, VSP2 and LOX2, in Arabidopsis. The neomycin-dependent reduced JA-Ile level is partially due to increased CYP94B3 expression and subsequent JA-Ile turn-over to12-hydroxy-JA-Ile. It is neither due to the inhibition of the enzymatic conjugation process nor to substrate availability. Thus, blocking Ca2+ elevation specifically controls JA-Ile accumulation and signaling, offering an insight into role of calcium in defense against insect herbivory. 相似文献
38.
Yachin Cohen Efim Gartstein Karl-Friedrich Arndt Wilhelm Ruland 《Polymer Engineering and Science》1996,36(10):1355-1359
Materials exhibiting exceptional mechanical properties can be fabricated from rigid polymers. In a spinning process, an oriented solution is solidified by the action of a nonsolvent, which induces crystallization of an oriented rigid polymer. Drying and heat treatment result in the final material having the desired properties. The effect of heat treatment on the morphology of poly(p-phenylene benzobisthiazole) (PBZT) films was studied by measurements of small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD). Films were formed by coagulation in water. The wet films were dried with supercritical CO2 to maintain an open network structure. Coagulation in water resulted in formation of microfibrils having diameter of ∼9 nm. Heat-treatment at 600°C caused significant coalescence of microfibrils. The crystallite size was increased by heat treatment from a value that is smaller than the microfibrillar diameter indicating defects in chain packing, to a value comparable to the microfibrillar diameter. 相似文献
39.
Jrg Hofmann Gerhard Just Wilhelm Pritzkow 《Advanced Synthesis \u0026amp; Catalysis》1991,333(1):67-71
The title compounds were prepared from 2,4-dioxohexahydro-triazine (DHT) and the corresponding acid chlorides in the presence of sulphuric acid. They are active acylating agents against piperidine in dioxane as the solvent. Only the diacyl derivatives of DHT with acyl chain lengths up to C6 react with aqueous solutions of sodium perborate forming the corresponding peroxy acids. 相似文献
40.
Birgit Batke Gerlinde Lauterbach Wilhelm Pritzkow Volkmar Voerckel Vladimir A. Belyakov 《Advanced Synthesis \u0026amp; Catalysis》1989,331(3):424-430
The products of the autoxidation of phenyl cyclopropane ( I ), phenyl cyclobutane ( II ), phenyl cyclopentane ( III ), phenyl cyclohexane ( IV ), phenyl cycloheptane ( V ) and phenyl cyclooctane ( VI ) were analyzed after reduction of the reaction mixtures with LiAlH4. As products of the attack on the α-C H bonds the corresponding 1-phenyl cycloalkanols and 1-phenyl alkan-1-ols were found. In the case of phenyl cyclopropane some SR2 ring opening probably takes place. The oxidabilities $ {\rm k}_{\rm p} /\sqrt {{\rm k}_{\rm t}} $, the chain termination constants kt, the absolute chain propagation constants kp and the relative chain propagation constant (kp)rel were determined for the phenyl cycloalkanes I — VI . As it is to be expected on the basis of the I-strain concept the autoxidation rate of phenyl cyclopentane ( III ) is considerably higher than that of phenyl cyclobutane ( II ) and phenyl cyclohexane ( IV ). 相似文献