THERMAL STABILITY ANALYSIS OF THE LIQUID PHASE METHANOL SYNTHESIS REACTOR

ABSTRACT

The effect of addition of an inert liquid phase on the rate of heat generation in the catalytic synthesis of methanol from syngas has been studied. Gas compositions typical of product gases from Lurgi and Koppers-Totzek gasifiers, represented by H₂-rich and CO-rich syngas respectively, were used to experimentally verify the “slope” and “dynamic” critria in a three-phase fixed bed recycle reactor. The liquid medium, witco-40 oil, has been effective in controlling the rate of heat generation and in preventing catalyst overheating, signifying that the liquid phase synthesis is thermally far more stable than the vapor phase synthesis. The experimental thermal stability study provides crucial and valuable information in commercializing the liquid phase methanol synthesis process. The current approach of thermal stability analysis does not require any a priori assumption or predetermined reaction kinetics.     

Hydrolysis of fatty acid esters in subcritical water

Hydrolysis of esters of higher fatty acids by subcritical water, performed in a flow‐through tubular reactor, was investigated at temperatures from 280 up to 340 °C and pressures exceeding 12 MPa, using an ester/water ratio of 1 : 2 or 1 : 4 (vol/vol). The kinetics of the hydrolysis of both the triacylglycerols and the methyl esters obeyed the rate equation valid for first‐order reactions. Conversion of the esters to free fatty acids exceeding 95% was reached at the temperature of 340 °C during 12 min. IR spectroscopy revealed structural changes in the chains of the unsaturated fatty acids and their partial polymerization during the hydrolysis.     

Thermoelastic behavior of carbon fiber/polycarbonate model composites

Model composites of polycarbonate (PC) containing single, multiple and chopped carbon fibers (CF) with and without and epoxy sizing were prepared by hot pressing. The thermoelastic behavior of model CF/PC composites was characterized by stretching calorimetry at room temperature. For small strains ? (i.e., ? ≈ 0.01) the specific mechanical work, specific heat effects and specific internal energy changes ΔU were completely reversible in stretching/contraction cycles and quantitatively obeyed the standard relationships for elastic solids. Young's moduli E and ΔU were significantly higher, whereas the linear thermal expansivities α_L were lower for model CF/PC composites compared to those for the neat PC. Smaller values of the above parameters for composites reinforced with sized CF suggested weaker CF/PC interfacial interactions. Current theoretical models of thermoelastic properties of composite materials suggest the existence of unusually stiff, highly oriented PC structures in fairly thick boundary layers around CF. The onset of inelastic deformation, as well as mechanical failure in CF/PC model composites at significantly smaller strains compared to the neat PC were tentatively explained by the yield and subsequent plastic flow of the matrix polymer initiated by heat effects of fiber fragmentation processes, and by higher concentration of microvoids generated in fiber fragmentation/debonding events, respectively.     

EDGeS: Bridging EGEE to BOINC and XtremWeb

Desktop Grids, such as XtremWeb and BOINC, and Service Grids, such as EGEE, are two different approaches for science communities to gather computing power from a large number of computing resources. Nevertheless, little work has been done to combine these two Grid technologies in order to establish a seamless and vast Grid resource pool. In this paper we present the EGEE Service Grid, the BOINC and XtremWeb Desktop Grids. Then, we present the EDGeS solution to bridge the EGEE Service Grid with the BOINC and XtremWeb Desktop Grids.     

Preparation of PTFE/graphene nanocomposites by compression moulding and free sintering: A guideline

This work was aimed at preparing polytetrafluoroethylene (PTFE) nanocomposites filled with graphene nanoplatelets and investigating how the graphene nanoplatelets and the preparation techniques influenced the physical properties. Graphene was incorporated up to 4 vol % of the total PTFE system by dry and solvent assisted blending. The powder compaction was evaluated using the Kawakita/Ludde model to describe the compressibility of the powder blends. The nanocomposite billets were prepared using cold compression moulding by applying preform pressures between 12.7 and 140 MPa and the preform billets were sintered at 380°C using a specific sintering cycle. The changes in the physical dimensions, billet mass, density, and void content of the billets, pre and post sintering, were analyzed with experimental design to evaluate the influence of the precompaction pressure and graphene loading. From the evaluation it was concluded that the ideal compaction pressure was at 12.7 MPa and the solvent assisted blending was superior to the mechanical blending method. Furthermore, the compression creep tests confirmed the ideal processing temperature and graphene loading range to improve the mechanical properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43369.     

A Detailed Experimental Study of the LEO Satellite to Indoor Channel Characteristics

General investigations and results from ratherextensive measurement campaigns are presented tocharacterize the propagation channel of SatellitePersonal Communication Systems; in the measurements the satellite was simulated by a helicopter andmeasurements at S band and L band were made. A newconceptual partitioning of the full link is introduced;the measrement equipment and the environment aredescribed. The major part of the paper deals withpresentation of the measurement results and theiranalyses. Measured and analyzed are average lossincluding satellite elevation and azimuth positiondependence, first-order statistics, Doppler characteristics, andwide-band characteristics. Finally, some rather generalconclusions are drawn.     

µ-Opioid Receptors Expressed by Intrinsically Photosensitive Retinal Ganglion Cells Contribute to Morphine-Induced Behavioral Sensitization

Opioid drugs are the most effective tools for treating moderate to severe pain. Despite their analgesic efficacy, long-term opioid use can lead to drug tolerance, addiction, and sleep/wake disturbances. While the link between opioids and sleep/wake problems is well-documented, the mechanism underlying opioid-related sleep/wake problems remains largely unresolved. Importantly, intrinsically photosensitive retinal ganglion cells (ipRGCs), the cells that transmit environmental light/dark information to the brain’s sleep/circadian centers to regulate sleep/wake behavior, express μ-opioid receptors (MORs). In this study, we explored the potential contribution of ipRGCs to opioid-related sleep/circadian disruptions. Using implanted telemetry transmitters, we measured changes in horizontal locomotor activity and body temperature in mice over the course of a chronic morphine paradigm. Mice lacking MORs expressed by ipRGCs (McKO) exhibited reduced morphine-induced behavioral activation/sensitization compared with control littermates with normal patterns of MOR expression. Contrastingly, mice lacking MORs globally (MKO) did not acquire morphine-induced locomotor activation/sensitization. Control mice also showed morphine-induced hypothermia in both the light and dark phases, while McKO littermates only exhibited morphine-induced hypothermia in the dark. Interestingly, only control animals appeared to acquire tolerance to morphine’s hypothermic effect. Morphine, however, did not acutely decrease the body temperature of MKO mice. These findings support the idea that MORs expressed by ipRGCs could contribute to opioid-related sleep/wake problems and thermoregulatory changes.     

Enhanced separation of highly non-ideal mixtures with extractive heterogeneous-azeotropic distillation

The distillation based separation can be extremely complex if highly non-ideal mixtures are to be separated. In spite of different successfully applied unit operations there is still a possible way to improve the distillation technique and widen its toolbar. A new improvement in this area is the development of the extractive heterogeneous-azeotropic distillation (EHAD). This unit operation includes the merits of extractive- and heterogeneous-azeotropic distillations in one unit without extra material addition. Our work supports EHAD features with successful experiments compared with modelling and comparison with other separation structures proving that the application of EHAD makes the separation of extremely non-ideal mixtures possible on an easy, powerful, energy saving, and cost efficient way.     

Distinguishing logic from association in the solution of an invisible displacement task by children (Homo sapiens) and dogs (Canis familiaris): Using negation of disjunction.

Prior research on the ability to solve the Piagetian invisible displacement task has focused on prerequisite representational capacity. This study examines the additional prerequisite of deduction. As in other tasks (e.g., conservation and transitivity), it is difficult to distinguish between behavior that reflects logical inference from behavior that reflects associative generalization. Using the role of negation in logic whereby negative feedback about one belief increases the certainty of another (e.g., a disjunctive syllogism), task-naive dogs (Canis familiaris; n?=?19) and 4- to 6-year-old children (Homo sapiens; n?=?24) were given a task wherein a desirable object was shown to have disappeared from a container after it had passed behind 3 separate screens. As predicted, children (as per logic of negated disjunction) tended to increase their speed of checking the 3rd screen after failing to find the object behind the first 2 screens, whereas dogs (as per associative extinction) tended to significantly decrease their speed of checking the 3rd screen after failing to find the object behind the first 2 screens. (PsycINFO Database Record (c) 2010 APA, all rights reserved)