Cycles in the Chamber Homology of GL(3)

Let F be a nonarchimedean local field and let GL(N) = GL(N,F). We prove the existence of parahoric types for GL(N). We construct representative cycles in all the homology classes of the chamber homology of GL(3).     

Thermal and mechanical properties of polysulfide/epoxy copolymer system: the effect of anhydride content

Polymerization of a ternary system containing polysulfide (PS), as a liquid elastomer, diglycidylether of bisphenol A resin, and phthalic anhydride was conducted using “design of experiment” technique. The polymerization progress with respect to concentration variations of components were studied by Fourier transform infrared spectroscopy. Fourier transform infrared spectroscopy studies showed that the anhydride plays a decisive role in curing reaction so that, in its absence, the epoxy/PS mixture becomes gel in about 2 hr, whereas, by addition of the anhydride, the pot life of the system can be extended to 48 hr. The cured samples were investigated by thermal gravimetry analysis and differential scanning calorimetry to evaluate thermal properties. Thermal gravimetry analysis and differential scanning calorimetry results indicated that two different soft and hard segments are formed, which have different thermal decompositions. The soft segment consists of loose etheric bonds, which are attributed to PS, and the hard segment is formed during the etherification and esterification reactions of the epoxy resin. Tensile strength test was performed to investigate the mechanical properties of PS/epoxy/anhydride‐cured systems. The results showed that the tensile strength, elongation‐at‐break, and the fracture energy of specimens are essentially dependent on PS/anhydride ratios. Two different segments impart high strength and ductility simultaneously. Copyright © 2013 John Wiley & Sons, Ltd.     

Enhancement of Biogas Production by Co-digestion of Potato Pulp with Cow Manure in a CSTR System

Anaerobic digestion (AD) process is a well-established method to generate energy from the organic wastes both from the environmental and economical perspectives. The purpose of present study is to evaluate energy production from potato wastes by incorporating cow manure into the process. Firstly, a laboratory pilot of one-stage biogas production was designed and built according to continuously stirred tank reactor (CSTR) system. The setup was able to automatically control the environmental conditions of the process including temperature, duration, and rate of stirring. AD experiment was exclusively performed on co-digestion of potato peel (PP) and cow manure (CM) in three levels of mixing ratio including 20:80, 50:50, 80:20 (PP:CM), and 0:100 as control treatment based on the volatile solid (VS) weight without adding initial inoculums. After hydraulic retention time (HRT) of 50 days on average 193, 256, 348, and 149 norm liter (L_N) (kg VS)^?1, methane was produced for different mixing ratios, respectively. Statistical analysis shows that these gas productions are significantly different. The average energy was determined based on the produced methane which was about 2.8 kWh (kg VS)^?1, implying a significant energy production potential. The average chemical oxygen demand (COD) removal of treatments was about 61 %, showing that it can be leached significantly with high organic matter by the employed pilot. The energy efficiency of 92 % of the process also showed the optimum control of the process by the pilot.     

Synthesis of cyclopropane-fused α-chlorolactones utilizing the nucleophilicity of cyclopropylmagnesium carbenoids

A novel method for the synthesis of cyclopropane-fused α-chloro-γ-lactones was developed utilizing the nucleophilicity of cyclopropylmagnesium carbenoids. Cyclopropylmagnesium carbenoids were generated from i-PrMgCl and 1-chlorocyclopropyl p-tolyl sulfoxides with a [(phenoxycarbonyl)oxy]methyl group at the 2-position of the cyclopropane ring. The resulting cyclopropylmagnesium carbenoids reacted with an intramolecular carbonate unit to give 1-chloro-3-oxabicyclo[3.1.0]hexan-2-ones in moderate to good yields. The asymmetric synthesis of 1-chloro-3-oxabicyclo[3.1.0]hexan-2-one was achieved using optically active dichloromethyl p-tolyl sulfoxide as a starting material.     

Synthesis by UV-curing and characterisation of polyurethane acrylate-lithium salts-based polymer electrolytes in lithium batteries

UV-cured caprolactone-based polyurethane acrylate (PUA) polymer blend electrolytes were prepared and characterised. To develop polymer electrolytes suited to ambient temperature, an ionically-conductive and reliable polymer electrolyte based on urethane acrylate resins synthesised from a fluorine-containing di-functional oligomer 6F ethoxylated diacrylate, a di-functional reactive diluent 1,6-hexanediol diacrylate for adjusting the viscosity, and a radical photo-initiator doped with a mixture of lithium salts were used. Free-standing flexible electrolyte films were prepared by UV-curing via free-radical photopolymerisation. The performance of the lithium polymer cell system (Li/PE(F4)/LiCoO₂) was determined by electrochemical impedance spectroscopy, cyclic voltammetry, a galvanostatic recurrent differential pulse, chronocoulometry and chronoamperometry. The electrolyte with optimal amounts of fluorine-containing oligomer and optimal salt mixture content exhibited enhanced conductivity, showing a conductivity of 1.00 × 10^?4 S cm^?1 at ambient temperature. The specific capacity, specific energy and specific power of a Li/PE(F4)/LiCoO₂ cell were also determined.     

Identification of the Active Sites for Low Temperature CO Oxidation over Nanocrystalline Co3O4 Catalysts

The microstructural properties of dry‐grinding derived Co₃O₄ catalysts pretreated under different atmospheres, in relation to the activities on CO oxidation were investigated. The Co₃O₄ synthesized by soft reactive grinding and pretreated with O₂ resulted in the best activity, with 100% conversion of CO at ?52 °C, superior to that of Co₃O₄ pretreated with He. To find out the active sites on Co₃O₄ for low temperature CO oxidation, the characterizations of the cobalt oxides had been investigated by means of N₂ physisorption, XRD, TEM, H₂‐TPR, CO‐titration, XPS and O₂‐TPD technologies. XPS of Co2p results show that it is difficult to ascribe the difference in catalytic performance to the surface concentration of active Co³⁺ sites. A correlation between the activity and the CO‐titration and O₂‐TPD results for Co₃O₄ reveals that a high abundance of readily accessible superficial electrophilic oxygen (O^?) species is important for achieving a high activity. Therefore, CO oxidation takes place on the surface active oxygen sites in Co₃O₄ crystallites via the suprafacial mechanism.     

Kinetic,Equilibrium and Isotherm Studies of Cadmium Removal from Aqueous Solutions by Oxidized Multi‐Walled Carbon Nanotubes and the Functionalized Ones with Thiosemicarbazide and Their Toxicity Investigations: A Comparison

The multi‐walled carbon nanotubes (MWCNTs) were first oxidized by nitric acid to form a MWCNT‐COOH. Then, it was modified with thiosemicarbazide to produce MWCNT‐semi. Thus, these carbon materials, MWCNTs, MWCNT‐COOH and MWCNT‐semi, have been used as efficient adsorbents for the removal of cadmium from aqueous solutions. The influence of variables including pH, concentration of the cadmium, amount of adsorbents and contact time was investigated by the batch method. The kinetic studies carried out using different kinetic models such as pseudo‐first‐order, pseudo‐second‐order, and intraparticle diffusion models. The sorption process with each adsorbent was well described by pseudo‐second‐order kinetics which it was agreed well with the experimental data. The values of regression coefficient of various adsorption isotherms like Langmuir, Freundlich and Tempkin to obtain the characteristic parameters of each model have been carried out. The results showed which the Langmuir isotherm for all adsorbents and Tempkin model for MWCNT‐COOH and MWCNT‐semi was found to best represent the measured sorption data. Toxicity of these samples was evaluated in human embryonic kidney HEK293 and human breast cancer SKBR3 cell lines after culturing cells for 24 h. Cellular investigations showed that the modified MWCNTs in particular MWCNT‐semi have considerably significant toxic impact on SKBR3 as compared to HEK293 at concentration 3 µg/mL.     

Efficient Synthesis of New Thieno[2,3‐d]pyrimidin‐4(3H)‐one Derivatives for Evaluation as Anticancer Agents

Thieno[2,3‐d]pyrimidinones were reported to act as potent anticancer agents; in this work, a series of new substituted thieno[2,3‐d]pyrimidinone ( 6 ) were synthesized via the aza‐Wittig reaction in satisfactory yields. The structures of these compounds were confirmed by elemental analysis, IR, ¹H‐NMR, and mass spectral data, and compound 6h was further analyzed by single crystal X‐ray diffraction. Cytotoxic effect of all the compounds was carried out on human breast and lung cancer cell lines (MCF‐7 and SPC‐A‐1, A459). Compound 6f exhibited the best inhibition activities against A459 with IC₅₀ 4.1 μM.     

Vibrational spectroscopic investigation of methyl(5-[2-thienylcarbonyl]-1H-benzimidazol-2-yl: A comparative density functional study

FT-IR and Raman spectra of methyl(5-[2-thienylcarbonyl]-1H-benzimidazol-2-yl (nocodazole) are experimentally examined in the region of 4000–400 cm^?1. The optimized geometric parameters, conformational equilibria, normal mode frequencies, and corresponding vibrational assignments of nocodazole (C₁₄H₁₁N₃O₃S) calculated by means of the B3LYP hybrid density functional theory (DFT) method using the 6-31++G(d,p) basis set. Vibrational assignments are made based on the total energy distribution (TED) and the thermodynamic functions, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of nocodazole are calculated. Calculations are employed for four energetically possible conformers of nocodazole (N1, N2, N3, and N4) in the gas phase. A comparison between the experimental and theoretical results indicates that the B3LYP method is able to provide satisfactory results for predicting vibrational wavenumbers if calculated values are scaled properly and the structural parameters.     

Uniaxial Movements of a Metal–Cyanide Framework Switched by Weak Interactions through Dehydration and Rehydration

A metal–cyanide framework undergoes a dehydration–rehydration triggered reversible single‐crystal‐to‐single‐crystal transformation. The resulting accordion‐like contraction–expansion corresponds to a size change along the c axis as much as 24 %. This anisotropic response arises from the cooperativity among the water molecules, K ions, and CN groups between the unique two‐dimensional bimetallic layers through weak interactions of hydrogen bonds and electrostatic (ionic) interactions. The key role of the water molecules in the dehydration–rehydration process is revealed by solid‐state ¹H NMR spectroscopy and dielectric measurements.