Hydrogen transfer during co-liquefaction of Elbistan lignite and biomass: liquid product characterization approach

In this study, Elbistan lignite (EL) and manure were liquefied under catalytic conditions in an inert atmosphere. Red mud, tetralin, and distilled water were used as a catalyst and solvent, respectively. The liquefaction studies were carried out under catalytic conditions in the catalyst concentration of 9%, solvent/solid ratio of 3/1, reaction time of 60 min, waste/lignite ratio of 1/3, and at temperature of 400°C. Stirring speed and initial nitrogen pressure were kept constant at 400 rpm and 20 bar, respectively. At the end of liquefaction process, the soluble liquefaction products were separated by successive solvent extraction to preasphaltene, asphaltene, and oils. Oil products characterized by H-NMR to be able to differ hydrogen transfer from manure to EL surface. To obtain the hydrogen transfer way, liquefaction experiments conducted under inert atmosphere which does not related to hydrogen reaction, other above experimental conditions were kept same but only solvent type changed. The reason of using distilled water instead of tetraline is tetraline known as hydrogen donor but not water. Because water behaves supercritical conditions during the liquefaction stage. EL liquefied alone while using tetraline however EL liquefied with manure with using distilled water as a solvent. The obtained oil products form both experiments characterized by H-NMR. The radical groups diffraction and range values are not changed significantly shows that manure behaved as an hydrogen donor. So, EL with manure is the one great option to reduce cost of hydrogen source for direct coal liquefaction plant.     

Growing Innovative Calcium Carbonate Morphologies by Utilizing the Colloidal Gas Aphron System as a Surfactant-Based Template Method

Many studies have been conducted to study the various polymorphs and morphologies of calcium carbonate crystals in nature and living organisms. In this experimental work, a novel method has been employed to crystallize calcium carbonate by using colloidal gas aphron dispersion. The polymorph and morphology of prepared particles were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectrometry techniques. SEM and XRD analyses demonstrated that the morphology of synthesized CaCO₃ can be changed from spherical (vaterite phase) to novel rod and plate-like shapes (mixture of vaterite and calcite phases) with changes in the surfactant concentration. The quantitative examination results of different calcium carbonate polymorph orientations showed that the precursor concentrations had no significant effect on the orientation of calcite phase, but rather they affected the orientation development of vaterite phase at a higher surfactant concentration.     

线性支架回采工艺在榆家梁煤矿的使用与推广

根据神东煤炭分公司历年房采工作面的回采现状,以及神府矿区煤层赋存及顶底板岩性等情况,结合榆家梁煤矿42220房采工作面使用线性支架回采的尝试及效果,简单阐述新回采工艺在安全、效率、效益方面相对于以往回采工艺所具备的优势。     

4-硝基苯乙烯基吡啶类氢键液晶的合成及表征

该文用4-硝基苯甲醛和4-甲基吡啶合成了质子受体4-硝基苯乙烯基吡啶,用无水乙醇重结晶得黄色固体,其熔点126.8～128.9℃,产率27%。用4-羟基苯甲酸和1-溴代正烷合成了质子供体4-烷氧基苯甲酸,用体积分数为95%的乙醇重结晶,所得4种中间体产率都在20%左右。最后,以上述两个中间体为原料,制备了系列4-硝基苯乙烯基吡啶类氢键型液晶。IR和1H NMR证实了各中间体结构。POM、IR、DSC检测了各复合物。POM拍摄的向列相、近晶相液晶织构表明,3种该氢键复合物均呈现明显的液晶态,且n=3时为向列相,n=5、8时为近晶相;IR图谱3500～2500cm-1处峰的变化及羰基向高波数位移,证明了羧基和吡啶间的分子间氢键代替了羧基间的分子间氢键。各复合物的液晶区间范围比各相应单体增大了1倍,表明羧酸吡啶间氢键起到了稳定液晶态的作用。     

Synthesis and characterization of a thermotropic liquid crystalline hyperbranched polyester

BACKGROUND: Hyperbranched polymers have received increasing attention in the fields of medicine, homogeneous catalysis and materials science. Hydroxyl‐functional aliphatic polyesters are one of the most widely investigated families of hyperbranched polymers. The research reported here is based on the preparation of a novel hyperbranched polyester and the modification of its terminal hydroxyl groups by biphenyl mesogenic units. RESULTS: 2,2,6,6‐Tetramethylolcyclohexanol as a core and 8‐[4′‐propoxy(1,1‐biphenyl)yloxy]octanoic acid as a mesogenic unit were synthesized. A hyperbranched polyester (HPE) was synthesized in one step and subsequently substituted by reaction of its terminal hydroxyl groups with the biphenyl mesogenic units to yield a novel liquid crystalline hyperbranched polyester (HPE‐LC). The chemical structures of all compounds were confirmed using Fourier transform infrared, ¹H NMR and ¹³C NMR spectroscopy. The thermal behavior and the mesogenic properties of the biphenyl mesogenic unit and HPE‐LC were investigated using differential scanning calorimetry, polarized optical microscopy and wide‐angle X‐ray diffraction. The results demonstrated that the degree of branching of the HPE is ca 0.63. Both HPE‐LC and the biphenyl mesogenic unit exhibit mesomorphic properties, but HPE‐LC has a lower isotropic transition temperature and a wider transition temperature range than the biphenyl mesogenic unit. CONCLUSION: A novel liquid crystalline hyperbranched polyester was successfully synthesized, which exhibits mesomorphic properties. This polymer has good solubility in highly polar solvents and good thermal stability. Copyright © 2009 Society of Chemical Industry     

Chemical etching of a GaSb crystal incorporated with Mn grown by the Bridgman method under microgravity conditions

uring crystal growth can be reflected by the observations of etch pit distribution and other structural defects. Suggestions for improving the space experiment to improve the quality of the crystal are given.     

Electrochemical characterization of a polybenzimidazole-based high temperature proton exchange membrane unit cell

This work constitutes detailed EIS (Electrochemical Impedance Spectroscopy) measurements on a PBI-based HT-PEM unit cell. By means of EIS the fuel cell is characterized in several modes of operation by varying the current density, temperature and the stoichiometry of the reactant gases. Using Equivalent Circuit (EC) modeling key parameters, such as the membrane resistance, charge transfer resistance and gas transfer resistance are identified, however the physical interpretation of the parameters derived from EC’s are doubtful as discussed in this paper. The EC model proposed, which is a modified Randles circuit, provides a reasonably good fit at all the conditions tested. The measurements reveal that the cell temperature is an important parameter, which influences the cell performance significantly, especially the charge transfer resistance proved to be very temperature dependent. The transport of oxygen to the Oxygen Reduction Reaction (ORR) likewise has a substantial effect on the impedance spectra, results showed that the gas transfer resistance has an exponential-like dependency on the air stoichiometry. Based on the present results and results found in recent publications it is still not clear what exactly causes the distinctive low frequency loop occurring at oxygen starvation. Contrary to the oxygen transport, the transport of hydrogen to the Hydrogen Oxidation Reaction (HOR), in the stoichiometry range investigated in this study, shows no measurable change in the impedance data. Generally, this work is expected to provide a basis for future development of impedance-based fuel cell diagnostic systems for HT-PEM fuel cell.     

Faber-Schauder Wavelet Transform, Application to Edge Detection and Image Characterization

The Faber-Schauder wavelet transform is a simple multiscale transformation with many interesting properties in image processing. Some of these properties are: preservation of pixel ranges, arithmetic operations, non requirement of boundary processing, multiscale edge detection, elimination of the constant and the linear correlation, and the use of close neighboring information. In this study we describe this transformation and we propose a mixed scale visualization of the wavelet transform which makes it possible to show the transform result as an image. This visualization is used, with orientation information, to refine edge detection and image characterization by selecting regions with a high density of extrema wavelet coefficients.     

Metamer density estimated color correction

Color correction is the transformation of response values of scanners or digital cameras into a device- independent color space. In general, the transformation is not unique due to different acquisition and viewing illuminants and non-satisfaction of the Luther–Ives condition by a majority of devices. In this paper we propose a method that approximates the optimal color correction in the sense of a minimal mean error. The method is based on a representative set of reflectance spectra that is used to calculate a special basic collection of device metameric blacks and an appropriate fundamental metamer for each sensor response. Combining the fundamental metamer and the basic collection results in a set of reflectances that follows the density distribution of metameric reflectances if calculated by Bayesian inference. Transforming only positive and bounded spectra of the set into an observer’s perceptually uniform color space results in a point cloud that follows the density distribution of device metamers within the metamer mismatch space of acqcuisition system and human observer. The mean value of this set is selected for color correction, since this is the point with a minimal mean color distance to all other points in the cloud. We present the results of various simulation experiments considering different acquisition and viewing illuminants, sensor types, noise levels, and existing methods for comparison.