Laminar compressible flow between close rotating disks: An asymptotic and numerical study

Laminar steady compressible flow between close rotating thermally conducting axisymmetric disks with inflow was investigated by means of a numerical solution of the Navier-Stokes equation and an asymptotic analysis. The approximate solution, obtained for small ?, E and H (Rossby and Ekman numbers, and height/radius, respectively) is valid for “merged”, “close” and “separate” boundary layers on the disks, corresponding to β? 1, $\text{β ? 1}$ and β? 1, respectively (where $\text{β =}\text{H}\text{2}\text{√}\text{E}\text{ρ}$, and ρ is the non-dimensional density). These three cases may appear simultaneously in different regions of the same system due to the large variation of ρ in the radial direction. The small ? (i.e. negligible convection terms) does not necessarily imply small perturbations of the pressure, and a special treatment of the pressure term was used in order to account for this feature, which sometimes culminates in inversion of the radial pressure gradient. Thenumerical solution was obtained by a finite-difference, modified Cheng-Allen method, using a non-uniform mesh. The numerical and the approximate solution are in good agreement.     

Determination of three-dimensional structures of proteins by simulated annealing with interproton distance restraints. Application to crambin, potato carboxypeptidase inhibitor and barley serine proteinase inhibitor 2

An automated method, based on the principle of simulated annealing,is presented for determining the three-dimensional structuresof proteins on the basis of short (<5 Å) interprotondistance data derived from nuclear Overhauser enhancement (NOE)measurements. The method makes use of Newton's equations ofmotion to increase temporarily the temperature of the systemin order to search for the global minimum region of a targetfunction comprising purely geometric restraints. These consistof interproton distances supplemented by bond lengths, bondangles, planes and soft van der Waals repulsion terms. The latterreplace the dihedral, van der Waals, electrostatic and hydrogen-bondingpotentials of the empirical energy function used in moleculardynamics simulations. The method presented involves the implementationof a number of innovations over our previous restrained moleculardynamics approach [Clore,G.M., Brünger,A.T., Karplus,M.and Gronenborn,A.M. (1986) J. Mol. Biol., 191, 523–551].These include the development of a new effective potential forthe interproton distance restraints whose functional form isdependent on the magnitude of the difference between calculatedand target values, and the design and implementation of robustand fully automatic protocol. The method is tested on threesystems: the model system crambin (46 residues) using X-raystructure derived interproton distance restraints, and potatocarboxypeptidase inhibitor (CPI; 39 residues) and barley serineproteinase inhibitor 2 (BSPI-2; 64 residues) using experimentallyderived interproton distance restraints. Calculations were carriedout starting from the extended strands which had atomic r.m.s.differences of 57, 38 and 33 Å with respect to the crystalstructures of BSPI-2, crambin and CPI respectively. Unbiasedsampling of the conformational space consistent with the restraintswas achieved by varying the random number seed used to assignthe initial velocities. This ensures that the different trajectoriesdiverge during the early stages of the simulations and onlyconverge later as more and more interproton distance restraintsare satisfied. The average backbone atomic r.m.s. differencebetween the converged structures is 2.2 ± 0.3 Åfor crambin (nine structures), 2.4 ± 0.3 Å forCPI (eight structures) and 2.5 ± 0.2 Å for BSPI-2(five structures). The backbone atomic r.m.s. difference betweenthe mean structures derived by averaging the coordinates ofthe converged structures and the corresponding X-ray structuresis 1.2 Å for crambin, 1.6 Å for CPI and 1.7 Åfor BSPI-2.     

Statistischer Größeneinfluß unter mehrachsiger Wechselbelastung

Statistical Size Effect Under Alternating Load The results of 41 series of tests with smooth cylindrical and notched specimens, subjected to uni- and multiaxial alternating loads (tensioncompression, torsion, rotating bending and combined torsion and bending), are compared with theoretically predicted data. The prediction are based on the ?Weakest-Link-Concept”?. Multiaxial stresses are included either by means of suitable strength criteria, or by a fracturemechanical consideration of a crack in a multidimensional stress field. For the evaluation of the experimental data the 2-parametric Weibull's equation was used. The experimental and theoretical results may deviate by less than 20%, when the ratio between the strength at cyclic torsion and cyclic bending ist taken into account in the function of survival probability [eqns. (2), (7)].     

Children with asthma have improved pulmonary functions after massage therapy

OBJECTIVE: Opioid withdrawal has been associated with poor fetal growth, preterm delivery, and fetal death. We sought to evaluate the safety of antepartum opioid detoxification in selected gravidas. METHODS: Between 1990 and 1996, women with singleton gestations who reported opioid use were offered inpatient detoxification. Predetoxification sonography was performed to confirm gestational age and to exclude fetuses with growth restriction and oligohydramnios. Women with mild withdrawal symptoms were given clonidine initially, and methadone was substituted if symptoms persisted. Objective signs of withdrawal were treated with methadone from the outset. Antenatal testing was performed once gestations reached 24 weeks. Newborns were observed for signs of neonatal abstinence syndrome and were treated as necessary. Obstetric and neonatal outcome data were collected. RESULTS: Thirty-four gravidas elected to undergo opioid detoxification at a mean gestational age of 24 weeks. The median maximum dose of methadone was 20 mg per day (range 10-85 mg), and the median time to detoxification was 12 days (range 3-39 days). Overall, 20 women (59%) successfully underwent detoxification and did not relapse, ten (29%) resumed antenatal opioid use, and four (12%) did not complete detoxification and opted for methadone maintenance. There was no evidence of fetal distress during detoxification, no fetal death, and no delivery before 36 weeks. Fifteen percent of neonates were treated for narcotic withdrawal. CONCLUSION: In selected patients, opioid detoxification can be accomplished safely during pregnancy.     

A review of the air oxidation of aqueous sulphide solutions

The oxidation by air or oxygen of aqueous solutions of sulphides is reviewed. Some additional data obtained by the authors is also included. A hypothesis is advanced explaining the widely accepted catalytic effects operative in this reaction in terms of a coupled pair of electrochemical reactions.     

Identification and composition of turnip root lipids

Two varieties of turnip, Laurentian and Wye, were examined for their lipid and fatty acid composition. Lipids extracted with 80% ethanol contained variable quantities of phosphatidic acid, which was considered to be an artifact. Crude lipids were fractionated by TLC, and fatty acids and sterols were analyzed by GLC. Among the common phospholipids, cardiolipid and phosphatidyl glycerol were abundant components. Linolenic acid comprised 60% of the total fatty acids. β-Sitosterol was the principal sterol, and about half of the carotenoids was lycopene. No great differences between the two varieties studied were observed however. Contribution No. 53 of the Food Research Institute, Canada Department of Agriculture, Ottawa.     

Heterogeneity and patterning in the quasi-static behavior of granular materials

Heterogeneity is classified in five categories– topologic, geometric, kinematic, static, and constitutive–and the first four categories are investigated in a numerical DEM simulation of biaxial compression. The simulation experiments show that the topology and geometric fabric become more variable during loading. The measured fluctuations in inter-particle movements are large, they increase with loading, and they extend to distances of at least eight particle diameters. Deformation and rotation heterogeneity are large and are expressed in spatial patterning. Stress heterogeneity is moderate throughout loading.     

Computer analysis of finite planar arrays of circular multimodehorns

Software for accurately modelling finite planar arrays of identical circular multimode horns with arbitrary wall contours has been developed and validated. The authors describe the analysis concept followed, and presents a comparison between theoretical and experimental results