Numerical Simulations of Lubricating Grease Flow in a Rectangular Channel with and without Restrictions

This article presents numerical simulations of the laminar flow of lubricating greases in a channel with rectangular cross section. Three greases with different consistencies (NLGI grades 00, 1, and 2) have been considered in three different configurations composed of a rectangular channel without restrictions, one rectangular step restriction, and one double-lip restriction. The driving pressure drop over the channel spans from 30 to 250 kPa. The grease rheology is described by the Herschel-Bulkley rheology model, and both the numerical code and rheology model have been validated with analytical solutions and flow measurements using micro-particle image velocimetry.     

Thermal influence on torque transfer of wet clutches in limited slip differential applications

Wet clutches operating under low velocity and high load are studied with the aim of obtaining reliable models for the torque transfer during boundary lubrication conditions. A friction model which takes temperature, speed and nominal pressure into account is developed and used with temperature calculations to be able to simulate behavior of a wet clutch working in boundary lubrication regime. Predicted torque and temperatures from the model agree well with experimental data.     

Energy saving in existing housing

In one of several pilot projects financed through the Swedish Council of Building Research, the Department of Building Technology at the Royal Institute of Technology, Stockholm, showed how energy consumption could be reduced by more than 50 per cent in a typical three-storey block of flats built around 1940. Thermal insulation levels of the building were low by Swedish standards — walls and roofs having U-values of 1.2 W/m². °C — and oil consumption was as high as 60 litres per m² of net dwelling area.     

Occurrence of Gasterophilus intestinalis and some parasitic nematodes of horses in Sweden

The biological accuracy of a nonlinear compartmental model describing the in vivo kinetics of L-3,4-dihydroxy-6-[18F]fluorophenylalanine ([18F]FDOPA) metabolism was investigated. Tissue activities for [18F]FDOPA and its labeled metabolites 3-O-methyl-[18F]FDOPA ([18F]OMFD), 6-[18F]fluorodopamine ([18F]FDA), L-3,4-dihydroxy-6-[18F]fluorophenylacetic acid ([18F]FDOPAC), and 6-[18F]fluorohomovanillic acid ([18F]FHVA) were calculated using a plasma [18F]FDOPA input function, and kinetic constants estimated previously by chromatographic fractionation of 18F-labeled compounds in plasma and brain extracts from rat. Present data accurately reflected the measured radiochemical composition in rat brain for tracer circulation times past 10 min. We formulated the hypothesis that the discrepancy between calculated and measured fractions of [18F]FDOPA and the deaminated metabolite [18F]FDOPAC at times earlier than 10 min reflected storage of [18F]FDA in vesicles without monoamine oxidase. This hypothesis explained the initially rapid appearance of [18F]FDOPAC in striatum by delayed transfer of [18F]FDA from cytosol into vesicles. We conclude that the simpler model of [18F]FDOPA compartmentation is accurate when the cytosolic and vesicular fractions of [18F]FDA are at steady-state; the approach to equilibrium has a time constant of 15-30 min. The present model is valid for positron emission tomography studies of [18F]FDOPA metabolism in living brain.     

Phase-Field Modeling of Sigma-Phase Precipitation in 25Cr7Ni4Mo Duplex Stainless Steel

Phase-field modeling is used to simulate the formation of sigma phase in a model alloy mimicking a commercial super duplex stainless steel (SDSS) alloy, in order to study precipitation and growth of sigma phase under linear continuous cooling. The so-called Warren–Boettinger–McFadden (WBM) model is used to build the basis of the multiphase and multicomponent phase-field model. The thermodynamic inconsistency at the multiple junctions associated with the multiphase formulation of the WBM model is resolved by means of a numerical Cut-off algorithm. To make realistic simulations, all the kinetic and the thermodynamic quantities are derived from the CALPHAD databases at each numerical time step, using Thermo-Calc and TQ-Interface. The credibility of the phase-field model is verified by comparing the results from the phase-field simulations with the corresponding DICTRA simulations and also with the empirical data. 2D phase-field simulations are performed for three different cooling rates in two different initial microstructures. A simple model for the nucleation of sigma phase is also implemented in the first case. Simulation results show that the precipitation of sigma phase is characterized by the accumulation of Cr and Mo at the austenite-ferrite and the ferrite-ferrite boundaries. Moreover, it is observed that a slow cooling rate promotes the growth of sigma phase, while a higher cooling rate restricts it, eventually preserving the duplex structure in the SDSS alloy. Results from the phase-field simulations are also compared quantitatively with the experiments, performed on a commercial 2507 SDSS alloy. It is found that overall, the predicted morphological features of the transformation and the composition profiles show good conformity with the empirical data.

     

Polyclonal expansion of cells with trisomy 7 in synovia from patients with osteoarthritis

Trisomy 7 as the single chromosome aberration has been found in a variety of neoplasms and in normal tissue in the proximity of tumors, as well as in non-neoplastic lesions. Recently, we described a nonrandom pattern of chromosome aberrations, in particular, a gain of chromosome 7, in synovia, cartilage, and osteophytes from patients with osteoarthritis. To study the clonal origin of trisomy 7 in osteoarthritis, multiple synovial samples were collected from five women, all of whom were informative heterozygotes with regard to the X-linked human androgen receptor gene (AR). From each case, three to four independent cell cultures were initiated. Trisomic cell populations were subcloned from the individual cultures, and it was established whether or not the same allele of AR was inactivated in trisomic cells from different parts of the same joint. The finding of a polyclonal X-inactivation pattern in two of the cases provides strong evidence that gain of an extra copy of chromosome 7 occurs independently in multiple cells.     

Care in psychiatry--caring for and supervising is possible with a "parent role"

The effect of superoxide dismutase (SOD) and selenium on the blood level of ferritin and transferrin in patients with hemoblastosis was studied. Two-month treatment with SOD and selenium had no effect on the level of ferritin but reduced the concentration of malonic dialdehyde (MDA) in the native erythrocytes in patients with chronic lymphoid leukemia practically to that in healthy individuals. In erythrocytes which formed from cells of the leukemic clone (chronic myelocytic leukemia and erythremia) treatment with SOD and selenium reduced the pathologically high level of ferritin, but at the same time increased the concentration of MDA in the erythrocytes. In erythremia in the group with a low level of ferritin SOD and selenium caused no statistically significant increase in its level in blood.     

M2, M3 and M4, but not M1, muscarinic receptor subtypes are present in rat spinal cord

Muscarinic receptors in the spinal cord have been shown to mediate antinociception and alter blood pressure. Currently, there is much interest in identifying which muscarinic receptor subtypes regulate these functions. Toward that end, this study aimed to identify and localize the muscarinic receptor subtypes present in spinal cord using in vitro receptor autoradiography with [3H]-pirenzepine and [3H]-N-methylscopolamine. The results showed that M2 binding sites were distributed throughout the dorsal and ventral horns, whereas M3 binding sites were localized to laminae I to III of the dorsal horn. Only background levels of M1 binding sites were detected. Saturation binding assays using [3H]-pirenzepine in spinal cord homogenates confirmed the absence of M1 receptors. Competition membrane receptor assays using [3H]-N-methylscopolamine and the unlabeled antagonists pirenzepine, 11-2[(-[(diethylamino)methyl]-1-piperidinyl)-acetyl]-5, 11-dihydro 6H-pyrido(2, 3-b)(1, 4) benzodiazepine-one, methoctramine, and methoctramine in combination with atropine corroborated the autoradiographic findings and also revealed the presence of M4 binding sites. The finding that M2 and M3 binding sites were localized to the superficial laminae of the dorsal horn where nociceptive A delta and C fibers terminate suggests the possibility that either or both of these muscarinic receptor subtypes modulate antinociception. The present demonstration of M4 binding sites in spinal cord is consistent with the possibility that M2 and/or M4 receptors are involved in the regulation of blood pressure at the spinal level.