Mammalian exocrine secretions: X. constituents of preorbital secretion of grysbok,Raphicerus melanotis

Using electron impact and chemical ionization mass spectrometry with methane and nitric oxide as reactant gases in conjunction with mass spectral analysis of the dimethyl disulfide derivatives of unsaturated constituents, 51 compounds have been identified in addition to the compounds previously found in the preorbital secretion of the grysbokRaphicerus melanotis. The compounds identified are saturated, monounsaturated, and diunsaturated alcohols and formates, saturated and monounsaturated aldehydes, saturated carboxylic acids,- and-lactones, alkyl methyl sulfides, and-hydroxyalkyl acetates. All of these compounds have unbranched structures. The constituent previously incorrectly identified as (Z)-5-tetradecen-1-ol, was found to consist of the coeluting (Z)-7- and (Z)-8-tetradecenols.     

Quantitative studies by differential scanning calorimetry of the reaction between hydrogen peroxide and lignocellulose

Heat of reaction and kinetic parameters were determined by differential scanning calorimetry for decomposition of hydrogen peroxide, reaction of hydrogen peroxide with lignocellulosic materials, glucose and pinitol, and for the reaction of the same materials with produced or introduced oxygen. The heat of decomposition of hydrogen peroxide obtained in N₂ (720 cal/g H₂O₂) was in fair agreement with literature data, considering the different temperature and pressure conditions. The heats of reaction of hydrogen peroxide and lignocelluloses were higher when determined in N₂ (1670–2500 cal/g H₂O₂) than in O₂ (1450–2020 cal/g H₂O₂) atmosphere. The activation energy for decomposition of hydrogen peroxide amounted to 20.3 kcal/mol in N₂ and 15.9 kcal/mol in O₂ with frequency factors of 5.7 × 10⁹ and 3.7 × 10⁷ min^?1, respectively. The activation energies for the reaction of hydrogen peroxide and lignocellulosic materials tested were similar and not influenced by the atmospheric composition, ranging overall between 19.7 and 22.4 kcal/mol. The corresponding frequency factors ranged between 2.77 × 10⁹ and 2.23 × 10¹¹.     

Distribution coefficients and diffusivities in three polymers for nineteen aqueous nonvolatile solutes

Experimental results at 25°C are reported for infinite‐dilution distribution coefficients for 19 nonvolatile solutes between aqueous solution and three kinds of polymer films, and for their diffusion coefficients in the polymer matrix. The experiments were performed by coupling UV spectroscopy and gravimetric measurements with mass balances. The solutes are aromatic nonvolatile compounds that are of interest in environmental technology and may serve as model compounds for drug‐delivery systems. The polymers are ethylene‐vinyl acetate copolymers with 33 (EVAc33) and 45 (EVAc45) weight percentage vinyl acetate, and poly(vinyl acetate) (PVAc) widely used in drug‐delivery devices. For PVAc, a long time is required to reach equilibrium. Because the required time is too long for reasonable experimental studies, equilibrium distribution coefficients were calculated from finite‐time data by using a diffusion model. The contribution of surface adsorption is shown to be negligible. Infinite‐dilution distribution coefficients K_s, defined as the volume fraction of solute in the polymer divided by that in water, tend to increase with vinyl acetate content; they range from near unity to several hundred. Diffusion coefficients, determined from time‐dependent sorption data, are significantly larger in EVAc copolymers (10^?10 to 10^?8 cm²/s) than in PVAc (10^?12 cm²/s). These data may be useful for design of membrane processes, for controlled delivery of drugs, and for application in packaging and storage of food, chemicals, and pharmaceuticals. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2041–2052, 2002     

Determination of the Oxidation State of Antimony, Iron and Vanadium in Mixed Vanadium and Iron Antimonate Oxide Catalysts

Vanadium and mixed vanadium and iron antimonates with rutile-type structures have been studied by XANES at Sb L₁ edge, ⁵⁷Fe Mössbauer spectroscopy and ESR spectroscopy at 77 K. The results showed that both antimony and iron remained at their highest oxidation state, i.e. Sb^V and Fe^III, whereas vanadium was present as V^III and V^IV. Two types of V^IV species were distinguished corresponding to well-isolated vanadyl species in distorted octahedral coordination and vanadyl species in the same coordination but close to each other and in a dipole–dipole interaction. Both V^III and total V^IV concentrations decreased when the iron content increased, whereas isolated V^IV concentration increased first and then decreased, with a maximum for x = 0.2 in Fe_xV_1-xSbO₄. The observed variations in cationic composition are discussed in relation with the catalytic properties of the compounds in the ammoxidation of propane. Isolated V^IV-O moieties appeared to be the most active and selective catalytic sites.     

纤维素酯膜的有机物渗透性

本文研究了经丙酮水溶液改性处理后的醋酸纤维素（CA）反渗透（RO）膜的有机物渗透性，在丙酮改性处理过程，透过CA－RO膜的丙酮溶剂量，开始时迅速下降，然后逐渐趋于零，多孔膜变成了致密均相膜，非对称性的超滤（UF）膜，纳滤（NF）膜，RO膜，分别经丙酮改性处理后，甲苯透过膜的渗透速率依次减少。孔径越小，脱盐率越低的RO膜，经改性处理后，甲苯渗透速率越小，三醋酸纤维素（CTA）与醋酸丁酸纤维素（CAB）二组分混的CTACAB膜，或者与醋酸丙酸纤维素（CAP）三组分共混的CTACABCAP膜，随着实验时间的延长，甲苯的渗透速率，前者逐渐下降到接近零时趋于稳定，后者没有变化，改性的CA膜和CTACAB共混膜分离甲基叔丁基醚（MTBE）／甲醇（MeOH)混合物时，渗透能量分别为835和226（g/m^2.h)，渗透物中MeOH浓度都达到88wt％。     

Digital image processing of combined SEM and EDX signals

Due to the complexity of biological tissue and man-made materials, the limits of light microscopy in quantitative image analysis are often reached. The scanning electron microscope provides a much higher resolution in such situations, especially when using the low noise secondary electrons signal. However, secondary electrons are sensitive to topography rather than to the elements constituting the specimen. This effect usually makes discrimination of distinct phases or objects by simple grey value thresholding difficult or even impossible. The additional information given by an energy dispersive X-ray system is the step to overcome this problem. The combination of both signals—grey level and energy dispersive information—leads to a masking procedure which eliminates image sections, not belonging to the phase under investigation, from the evaluation.     

Study on the preparation of ordered mesoporous carbon-based catalyst from waste microalgal biomass for the synthesis of biokerosene

Investigation on preparation of novel ordered mesoporous carbon-based catalyst (MCC catalyst) containing super-acid sites from waste microalgal biomass was established. The waste microalgal biomass was partially carbonized at 400 °C for 2 h obtaining biochar; then the obtained biochar was introduced to a sulfonation process using concentrated sulfuric acid. The sulfonation was established at 150 °C for 15 h producing sulfonated biochar. The MCC catalyst was prepared through condensation–evaporation method in an alkaline media containing cetyltrimethylammonium bromide (CTAB) as structure directing agent. The parameters of the condensation including time of evaporating and CTAB content were investigated while fixing temperature at 90 °C during the process. A special hydrothermal treatment was also applied to the preparation of the MCC catalyst in order to expand its mesopores for more convenient with large molecule diffusion. The catalyst activity was well demonstrated by converting linseed oil to biokerosene which could be used as biokerosene—component for blending with aviation fuels. The MCC catalysts were characterized by X-ray diffraction, infrared spectroscopy, energy dispersive X-ray, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption–desorption method and ammonia-temperature programmed desorption techniques. The biokerosene composition was determined by gas chromatography–mass spectroscopy method.     

Controlling microstructure and film growth of relaxor-ferroelectric thin films for high break-down strength and energy-storage performance

The relaxor ferroelectric Pb_0.9La_0.1(Zr_0.52Ti_0.48)O₃ (PLZT) thin films were deposited using pulsed laser deposition, and their microstructures, break-down field strengths and energy storage performances were investigated as a function of the buffer layer and electrode. A large recoverable energy-storage density (U_reco) of 23.2 J/cm³ and high energy-storage efficiency (η) of 91.6% obtained in the epitaxial PLZT film grown on SrRuO₃/SrTiO₃/Si are much higher than those in the textured PLZT film (U_reco = 21.9 J/cm³, η = 87.8%) on SrRuO₃/Ca₂Nb₃O₁₀-nanosheet/Si and the polycrystalline PLZT film (U_reco = 17.6 J/cm³, η = 82.6%) on Pt/Ti/SiO₂/Si, under the same condition of 1500 kV/cm and 1 kHz, due to the slim polarization loop and significant antiferroelectric-like behavior. Owing to the high break-down strength (BDS) of 2500 kV/cm, a giant U_reco value of 40.2 J/cm³ was obtained for the epitaxial PLZT film, in which U_reco values of 28.4 J/cm³ (at BDS of 2000 kV/cm) and 20.2 J/cm³ (at BDS of 1700 kV/cm), respectively, were obtained in the textured and polycrystalline PLZT films. The excellent fatigue-free properties and high thermal stability were also observed in these films.     

Swelling behavior of polymeric membranes to metalworking fluids

In some working places, such as metal manufacturing or automotive services, mechanical hazards commonly occur along with chemical hazards, particularly metalworking fluids (MWFs). The presence of these chemicals could modify the properties of gloves made from polymeric materials and thus reduce their protective properties against chemical contamination (solvent, MWFs) and mechanical risks (puncture and cutting). This work focused on determining the swelling characteristics and the resistance of six polymeric membranes which were exposed to seven industrial MWFs. We found that the swelling tests can be used to classify the potential of coating polymers in descending order of their resistance to MWFs: nitrile, polyurethane > poly(vinyl chloride), neoprene > butyl, latex. The analysis by multiple linear regression showed, for the first time, that the density or the viscosity‐gravity constant of the fluid and Hansen's solubility parameters of the polymers have a significant impact on the swelling of polymer. For the first time, two new multiple regression models have been proposed, to predict the swelling phenomena of polymers under various MWFs with an accuracy of ≈80%. The effect of temperature on mechanical properties and morphology of material was also examined. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45717.