Oxygen,Nitrogen, and Sulfur Removal Reactions in Donor Solvent Coal Liquefaction

There are a number of ways coal can be converted to liquid fuel. It can be pyrolyzed to produce gas, liquid, and char. It can be first converted to carbon monoxide and hydrogen which can then be converted to liquid fuel via Fischer-Tropsch synthesis. It can be hy-dropyrolyzed to produce gases, naphtha range liquids, and heavy residues. Finally, it can be liquefied in the presence of a hydrogen donor solvent to produce liquid and gaseous products. This review is concerned with the last method for conversion of coal to liquid fuel.     

Studies on the formation of yttrium iron garnet (YIG) through stoichiometry modification prepared by conventional solid-state method

Y₃Fe₅O₁₂ (YIG) prepared by conventional solid-state method can rarely be of high purity. However, this study suggests that high purity YIG can be produced via conventional solid-state methods, through stoichiometry modification. This is achieved by adding various amounts of excess Fe₂O₃ to control the YIG stoichiometric ratios. In this work, ferrite and yttria were calcined at 1100 °C (for 8 h) and sintered at 1420 °C (6 h). In most samples, the formation of YIG, with YFeO₃ (YIP) and/or Fe₂O₃ as associated phases were detected. Uniform microstructures of YIG are also observed. YIP phase in YIG is found to be inversely related to the addition of excess Fe₂O₃, up to 8 wt%. At above 8 wt% Fe₂O₃ addition, YIP disappears, leaving unreacted excess Fe₂O₃ as a new associated phase. From the investigation, it is safe to conclude that the purity of YIG can be increased with the addition of excess Fe₂O₃.     

Characterization of purified fungal endoxylanase and its application for production of value added food ingredient from agroresidues

Xylanase from Aspergillus foetidus MTCC 4898 was purified using ammonium sulphate fractionation followed by ion exchange and gel permeation chromatography with 12.26-fold purity and 29.9% recovery. Purified xylanase was found to be 29.9 kDa. Optimum temperature and pH for xylanase activity of purified xylanase were found to be 50 °C and 5.3 respectively. Presence of additives like polyethylene glycol, sodium azide, Tween 80, KCl and NaCl increased the stability of purified xylanase by 35, 29, 28, 32 and 43% respectively at 50 °C after 180 min. Kinetic parameters like K_m and V_max were found to be 4 mg/ml and 7288 μmol/mg/min respectively. The purified xylanase was found to be an endoxylanase as it produced only xylooligosaccharides (XOS) from birchwood xylan. Production of XOS was carried out from xylan extracted from agro-residues using β-xylosidase free xylanase. Maximum yield of XOS was 7.28 ± 0.14 mg/ml and 4.52 ± 0.21 mg/ml from wheat straw xylan and rice straw xylan respectively. XOS mixture was suitable for food industry looking at its high thermal stability at low pH. Prebiotic effect of XOS was evaluated by in vitro fermentation of XOS using known probiotic strains of Bifidobacterium spp.     

Cyclic Stretch Induces Inducible Nitric Oxide Synthase and Soluble Guanylate Cyclase in Pulmonary Artery Smooth Muscle Cells

In the pulmonary vasculature, mechanical forces such as cyclic stretch induce changes in vascular signaling, tone and remodeling. Nitric oxide is a potent regulator of soluble guanylate cyclase (sGC), which drives cGMP production, causing vasorelaxation. Pulmonary artery smooth muscle cells (PASMCs) express inducible nitric oxide synthase (iNOS), and while iNOS expression increases during late gestation, little is known about how cyclic stretch impacts this pathway. In this study, PASMC were subjected to cyclic stretch of 20% amplitude and frequency of 1 Hz for 24 h and compared to control cells maintained under static conditions. Cyclic stretch significantly increased cytosolic oxidative stress as compared to static cells (62.9 ± 5.9% vs. 33.3 ± 5.7% maximal oxidation), as measured by the intracellular redox sensor roGFP. Cyclic stretch also increased sGCβ protein expression (2.5 ± 0.9-fold), sGC activity (1.5 ± 0.2-fold) and cGMP levels (1.8 ± 0.2-fold), as well as iNOS mRNA and protein expression (3.0 ± 0.9 and 2.6 ± 0.7-fold, respectively) relative to control cells. An antioxidant, recombinant human superoxide dismutase (rhSOD), significantly decreased stretch-induced cytosolic oxidative stress, but did not block stretch-induced sGC activity. Inhibition of iNOS with 1400 W or an iNOS-specific siRNA inhibited stretch-induced sGC activity by 30% and 68% respectively vs. static controls. In conclusion, cyclic stretch increases sGC expression and activity in an iNOS-dependent manner in PASMC from fetal lambs. The mechanism that produces iNOS and sGC upregulation is not yet known, but we speculate these effects represent an early compensatory mechanism to counteract the effects of stretch-induced oxidative stress. A better understanding of the interplay between these two distinct pathways could provide key insights into future avenues to treat infants with pulmonary hypertension.     

Early age microstructure of Portland cement mortar investigated by ultrasonic shear waves and numerical simulation

This paper investigates the ability of a shear wave reflection (WR) method to monitor microstructural changes of Portland cement mortar during hydration. The wave reflection method measures the reflection loss of shear waves at an interface between a steel plate and mortar. Mortars with water/cement ratios of 0.35, 0.5 and 0.6 were tested at isothermal curing conditions of 25 °C. The numerical model HYMOSTRUC3D was used to simulate the evolution of microstructural properties of the cement paste phase of the tested mortars. The parameters obtained from the simulations were the volume fraction of the total and connected solid phase and the specific contact area of the hydrated cement particles. The investigations have shown that the wave reflection measurements are governed primarily by the degree of the inter-particle bonding of the cement particles as calculated from the specific contact area of a simulated microstructure.     

Flow and heat transfer of two immiscible fluids in double-layer optical fiber coating

The coatings of optical fibers are generally characterized by a multi-layer coating structure. In this work, the mathematical modeling of two immiscible non-Newtonian fluids for optical fiber coating inside a straight annular die is developed in the form of a nonlinear differential equation with nonhomogeneous boundary conditions. Two non-Newtonian fluids, namely power law and Phan-Thien–Tanner fluids, are used in the primary and secondary coating dies, respectively. An exact solution is obtained for velocity fields and temperature distributions for the primary and secondary coating resins. The thickness of coated fiber optics is also calculated for both layers. The effect of different emerging parameters on the solution is discussed and sketched.     

Aspects of varying crosslinker and catalyst concentrations on tear strength of silicone polymer networks: Comparison of tear strengths using samples of different geometries

Crosslinker and catalyst concentrations have been varied to prepare different hydroxyfunctional poly(dimethylsiloxane) (HOPDMS) polymer network compositions. The tear strengths of these silicone polymer networks have been measured using different geometries, as trouser, crescent, and Graves (angled) specimens. It has been observed that the results of tear strength of Graves and crescent‐shaped specimens do not show a constant ratio with the concentration of crosslinker used for curing of HOPDMS networks. Instead, it has been observed and reported for the first time that the tear strengths of Graves and crescent‐shaped samples show a crossover at about 1.2% crosslinker. The observation of this crossover pattern for different compositions of silicone networks show that it is difficult to compare the results of the tear test of the same polymer performed on samples of different geometries with one another. The crossover pattern of the tear energy results for the test specimens of two different geometries has been explained in the light of essential work facture theory based on the geometry of the testing sample, crosslinking, and testing that alters the distribution of force over the width of the specimen. It was shown that the change in composition of the HOPDMS networks changes the order of ranking of Graves and crescent tear tests. With varying catalyst concentration in the silicone network composition, the tear property differences between the Graves and crescent‐shaped specimens are not significant. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43115.     

Lamotrigine‐loaded polyacrylate nanoparticles synthesized through emulsion polymerization

A series of copolymeric nanoparticles of the partially water‐soluble monomer ethyl methacrylate and the water‐soluble monomer 2‐hydroxyl ethyl methacrylate were synthesized from emulsions containing sodium dodecyl sulfate via free‐radical polymerization. Lamotrigine, as a model drug, was loaded in nanoparticles during in situ polymerization. A stable and transparent poly(ethyl methacrylate‐co‐hydroxyl ethyl methacrylate) nanolatex was produced for all compositions and characterized for particle size by dynamic light scattering and transmission electron microscopy. Particles were found to be smaller than 50 nm in size. Structural characterization of copolymers was done by infrared spectrometry, gel permeation chromatography, and NMR spectroscopy. Drug encapsulation efficiency was determined by ultraviolet (UV)–visible spectrometry and was found to be 26–62% for copolymers with different compositions. UV data suggest molecular‐level dispersion of the drug in the nanoparticles. In vitro drug‐release studies showed the controlled release of lamotrigine. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008