Enhancement Of Fluidity Research Articles

99/00047 In situ1H NMR study of the fluidity enhancement for a bituminous coal by coal tar pitch and a hydrogen-donor liquefaction residue

99/00047 In situ1H NMR study of the fluidity enhancement for a bituminous coal by coal tar pitch and a hydrogen-donor liquefaction residue

Gas chromatographic study for the evaluation of the suitability of bituminous waste material as an additive for coke production

Waste materials derived from coking plants can be used in situ as bituminous additives in cokemaking. The effectiveness of such materials in the plastic coal range was compared with a coal-tar and four derived pitches of different applications. The volatile matter released from 400 up to 500°C by the additives (VM400–500), which was evaluated by thermogravimetric analysis, was clearly related to the extent of the modification of the Gieseler maximum fluidity of coking coal/additive blends. The decrease in the amount of volatile fraction in the CS 2 extracts of the additives and the increase in the abundance of polycyclic aromatic hydrocarbons (PAHs) of relatively high molecular mass were evaluated by capillary gas chromatography with flame ionization detection (GC–FID) analysis. From regression analysis, it can be deduced that there is a relationship between the compositional parameters deduced from GC–FID analysis and the volatile matter released in the plastic range of a coking coal (VM400–500). Both composition and VM400–500 of the additive, were found to be responsible for the enhancement in fluidity caused by the presence of the additive in the co-carbonization system. GC–FID analysis may be a good method to assess the effectiveness of a bituminous additive in the coal plastic stage and to acquire a better understanding of the components involved in this critical stage of the carbonization process. The changes induced in the plastic range by the additive modify the development of coke anisotropy and the bonding between coke matrix and inert material and, consequently, are responsible for the improvement in the coke properties.

In situ1H NMR study of the fluidity enhancement for a bituminous coal by coal tar pitch and a hydrogen-donor liquefaction residue

Hydrogen-donor ability has been ascribed as one of the factors responsible for stabilisation of the plastic phase during coal carbonisation. In situ high-temperature 1H nuclear magnetic resonance spectroscopy (NMR) is used here to compare quantitatively the interactions of a low-volatile, poor coking bituminous coal with a heat-treated coal tar pitch (CTP) and with a hydrogen-donor pitch (HDP) (> 450°C residue) obtained from a two-stage coal liquefaction process. When the CTP was added to the coal (25% w/w, 150–250 μm), the amount of fluid material increased by nearly 20% more than that predicted at maximum fluidity close to 450°C. Indeed, an even larger synergistic effect was observed with the HDP. By 400°C, 90% of the fluid phase concentration observed at 450°C had already been generated, corresponding to an enhancement of 50% over that predicted. However, particle size appears to be a dominant factor under the slow heating regime used, in that no enhancement in fluidity was detected when the coal size was < 45 μm.

97/02661 In-situ 1H NMR study of fluidity enhancement by hydrogen-donor and non-door pitches for a bituminous coal

Unusually abundant long-chain monomethylalkanes (MMAs) (C25–C36) and their short-chain homologues (C14–C22) have been tentatively identified in a Late Triassic oil sand sample from the Lunnan oilfield, Tarim Basin, NW China. Molecular distributions and stable carbon isotopic compositions of these compounds have been determined to investigate their bio- and/or geosynthetic sources. The results show that the most abundant isomers of short-chain MMAs were 4-methyl (m/z 70), 5-methyl (m/z 84), 6-methyl (m/z 98) and 7-methyl (m/z 112) alkanes, whereas in long-chain MMAs, there is a clear predominance of the 9-methyl and 10-methyl isomers. Combined with the compound-specific stable carbon isotopic analysis, it is concluded that short-chain MMAs and long-chain MMAs must have different sources. The similar isotopic compositions of MMAs and n-alkanes in this sample suggest that they may share the same sources. The short-chain MMAs, as previously suggested, are probably related to a cyanobacterial origin, while the long-chain MMAs may be mainly associated with microorganisms or heterotrophic bacteria, rather than cyanobacteria.

Enhancement of membrane fluidity in cholesterol-poor endothelial cells pre-treated with simvastatin.

We examined the membrane fluidity of the cholesterol-poor bovine carotid artery endothelial cells (BAEC). Cholesterol-poor BAEC were obtained by treating the cells with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors under 10% low density lipoprotein (LDL)-deficient serum condition for 2 days. Simvastatin reduced the intracellular cholesterol content significantly at a concentration of 0.1 microgram/ml. The reduction in the cholesterol content was accompanied by the enhancement of the cell membrane fluidity which was measured by a photobleaching technique. Additional data suggested that the reduction in cholesterol content referred to the reduction in the proliferation of BAEC.

Oxygen permeability of surfactant/polymer composite films with multibilayer and inverted hexagonal structure

AbstractThe permeability of oxygen through horizontally oriented multibilayer films of polyion complexes prepared from quaternary ammonium‐type surfactants [CH3(CH2)n‐1]2N+(CH3)2Br−(n = 14, 16, 18), and poly(p‐styrenesulfonate) or poly[2‐(acrylamido)‐2‐methyl‐1‐propanesulfonate], was measured in water using an oxygen electrode. The permeability depended mainly on the phase of the multibilayers. Thus, it increased abruptly (about 10‐fold) near each phase transition temperature because of the fluidity enhancement of the multibilayer. Inverted hexagonal type nonbilayer films prepared from the polyion complexes and cholesterol had greater permeability (2–20‐fold) than the multibilayer films in both phases. The large permeability of the nonbilayer films was attributed to the lack of a barrier such as the bilayer and lower crystallinity of the films. It was associated neither with an increase in thermal movement of the lipid surfactant molecules nor with an increase in the water content of the films by the addition of cholesterol. © 1993 John Wiley &amp; Sons, Inc.

Effect of Bothrops asper (Fer-De-Lance) snake venom on erythrocyte membrane. A comparative study

1. The effect of Bothrops asper venom on erythrocytes of different species, sheep erythrocyte ghost vesicles and liposomes made of phospholipids from sheep erythrocytes was studied. 2. B. asper venom had a direct hemolytic effect on mouse erythrocytes, but no lytic activity on goat, rabbit, horse, toad and sheep erythrocytes. Human erythrocytes were lysed only in the presence of bovine serum albumin and Ca 2+. 3. Although the phospholipase A 2 activity in the venom might be involved in the lytic effect on mouse erythrocytes, there is also evidence of direct lytic factor(s) acting in the absence of calcium ions. 4. Sheep erythrocytes were modified in order to study the basis of their resistance. Enhancement of membrane fluidity and variation of pH were of no consequence for the resistance of sheep erythrocytes to the action of venom. 5. The reorganization of membranes that takes place during ghost or liposome preparation made them susceptible to B. asper venom-induced disruption. Thus the resistance of sheep erythrocytes seems related to the accessibility of the target.

Nasal absorption enhancers for biosynthetic human growth hormone in rats.

The effects of several prospective absorption enhancers were assessed on the nasal absorption of biosynthetic human growth hormone (hGH) in the rat. These enhancers function by alternative mechanisms that include enzyme inhibition, reduction in mucus viscosity, and enhancement of membrane fluidity. The levels of plasma hGH achieved were determined by an enzyme-linked immunosorbent assay. The increase in peak height was calculated relative to nasal administration of hGH alone without any enhancers and the relative bioavailability was calculated with reference to subcutaneous injection data. A lysophospholipid, lysophosphatidylcholine, gave the highest peak concentration, with an increase in peak height of 450% and a relative bioavailability of 25.8%. However, the greatest increase in AUC (291%) was achieved with the aminopeptidase inhibitor, amastatin, which gave a relative bioavailability of 28.9%. A mucolytic agent, N-acetyl-L-cysteine, and a transmembrane fatty acid transporter, palmitoyl-DL-carnitine, were also found to promote the nasal absorption of hGH in this model, with relative bioavailabilities of 12.2 and 22.1%, respectively. Bestatin, an enzyme inhibitor, was not an effective absorption enhancer for hGH in this model.

A study of the mechanism by which some amphiphilic drugs affect human erythrocyte acetylcholinesterase activity.

The effects of the local anaesthetics procaine, tetracaine and lidocaine and of the antidepressant imipramine on human erythrocyte acetylcholinesterase were investigated. All four amphiphilic drugs inhibited enzymic activity, the IC50 (the concentration causing 50% inhibition) being about 0.40 mM for procaine, 0.05 mM for tetracaine, 0.70 mM for imipramine and 7.0 mM for lidocaine. Procaine and tetracaine inhibited acetylcholinesterase activity competitively at concentrations at which they did not perturb the physical state of the membrane lipid environment, as assessed by steady-state fluorescence polarization, whereas lidocaine and imipramine displayed mixed inhibition kinetics at concentrations at which they induced an enhancement of membrane fluidity. The question was addressed as to whether membrane integrity is a prerequisite for imipramine and lidocaine action. Membrane solubilization by 1% Triton X-100 and a decrease, by dilution, in the detergent concentration to 0.05% [which is above the Triton X-100 critical micelle concentration (c.m.c.)] did not substantially affect the inhibitory potency of the two amphiphilic drugs at their IC50; in the presence of increasing detergent concentrations the inhibitory potency of imipramine was gradually decreased, but not abolished, whereas the inhibitory effect of lidocaine was only slightly diminished, even at 1% Triton X-100. It is suggested that neither competitive nor mixed inhibition kinetics arise from conformational changes of the protein driven by a modification of the physical state of the lipid environment, but from a direct interaction of the amphiphilic drugs with acetylcholinesterase. In particular, the partial loss of the inhibitory potency of imipramine and lidocaine that is observed upon increasing Triton X-100 concentration well above its c.m.c. could be explained in terms of amphiphile partition in detergent micelles and, in turn, of a decreased effective concentration of the two inhibitors in the aqueous phase.

レシチン製剤の吸湿におよぼす添加剤の影響

The effects of various additives to protect Soya lecithin granules from moisture were investigated. Additives used were Adsolider-101®, Aerosil R-972® Neusilin UFL-2® and carnauba wax (mean diameter: 3μm). Weight increase, angle of repose, aggregation rate and disintegration time of the lecithin granules were measured to evaluate the effect of additives on moisture protection and fluidity.The hygroscopicity of the lecithin granules decreased with an increase in the amount of additives. Aerosil R-972® was not adhered uniformly to the lecithin granules. The addition of 2-3% of Adsolider-101® and Neusilin UFL-2® prevented the hygroscopicity and enhanced the fluidity of lecithin granules, though the appearance changed to white. It was considered. that carnauba wax in the proportion of 5% was very useful for the prevention of hygroscopicity and the enhancement of fluidity of the lecithin granules.

Parafluidity in helium near the ?-transition and the generalized time-dependent Landau theory

A phenomenological theory of parafluidity, i.e., an enhancement of fluidity due to order-parameter fluctuations, is presented for helium near the 2 transition. The generalized time-dependent Landau theory of second-order phase transitions is reviewed in general and is applied to the superfluid transition in helium as a particular example. In helium, it is found that parafluidity is manifested in the divergences of the mass diffusivity Dm oc e -~, the thermal conductivity t¢ oc e -~, the first-sound amplitude attenuation ~ ~ lel- ~, and the second-sound damping D 2 ~ (-g)-~, which are all consistent with the dynamic scaling hypothesis. Here a characteristic relaxation time Zo oc ]el- 1 is used, where e = (T - To)/Tc and T o is the transition temperature. Although there are not enough experimental data to confirm our formulas, the present approach is seen to agree in order of magnitude with available experiments. Finally, the sound absorption above a ferromagnetic transition is calculated by adding a diffusion term to the generalized time-dependent Landau equation. The result thus obtained agrees in order of magnitude with experiments in nickel.