Comparison of different methods of modeling turbulent combustion in a boundary layer

Three methods of modeling a chemical reaction in the combustion of ethanol injected into the boundary layer through a porous plate are compared. In calculations of the average velocity and temperature and also heat-transfer coefficients, simple models of combustion are shown to be close in accuracy to a model that takes into complete account the kinetics of all reactions occurring during combustion. Simple models fail to determine the composition of reaction products, and it is necessary to take into account the formation rate of each substance entrained in combustion.Translated from Fizika Goreniya i Vzryva, Vol. 32, No. 4, pp. 37–42, July–August, 1996.     

Revisiting single sign-on: a pragmatic approach in a new context

Single sign-on is a solution that lets users authenticate themselves once and access different applications without reauthentication. SSO assists users through all the procedures required to access heterogeneous applications. Using applications becomes easier, technical-assistance costs go down, and security improves. However, getting the most of the solution requires understanding related domains such as central user administration, the enterprise directory, and Web single sign-on. SSO is a moving target in a changing context. Many new devices, applications, and authentication methods are on the horizon, and although the general issue remains relatively simple and clearly defined, the solution's integration in an IT environment can become complicated. For these reasons, I draw attention to some of the main problems related to SSO initiatives and discuss the SSO strategy at Pictet, a private Swiss bank     

Determining the quantity of material worn away from a wall in a turbulent boundary layer as a consequence of chemical erosion when an inert inhomogeneous gas is added by injection through the entrained surface under conditions of substantial nonisothermicity

We propose an analytical method of calculating the entrainment of wall material when an inert gas is additionally injected to that wall in a turbulent boundary layer. The calculation is carried out for the case of carbon entrainment when additional argon and helium are injected through a carbon wall when b_g=const under conditions of substantial nonisothermicity.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 17, No. 1, pp. 31–36, July, 1969.     

Magnetosensitive transducers for nondestructive testing operating on the basis of the giant magnetoimpedance effect: A review

Experimental data on and model representations of the physical processes in small detectors operating on the basis of the magnetoimpedance effect are analyzed and generalized for conditions adapted to systems of magnetic nondestructive testing. The principles of measuring the high-frequency magnetoimpedance effect in electronic circuits including a sensitive element of a detector of weak magnetic fields are briefly described. The data on the available devices for nondestructive testing (NDT) based on the magnetoimpedance effect are systematized and examples of typical approaches are presented.     

The nonstructural small glycoprotein sGP of Ebola virus is secreted as an antiparallel-orientated homodimer

An earlier report indicated that a 26-amino-acid peptide (SA), comprised of the nuclear localization signal (NLS) of fibroblast growth factor-1 (FGF-1) and a membrane-permeable peptide, was able to stimulate DNA synthesis after it was taken up by NIH3T3 fibroblasts. Here, we report that SA, but not a mutant with the NLS motif destroyed, induced DNA synthesis in BALB/c3T3 murine fibroblasts, human vascular endothelial (HUVE) cells, and primary cultured hepatocytes, although the activity was weaker than that of FGF-1. The kinetics of SA-induced DNA synthesis and G1 cyclin expression were similar to those elicited by FGF-1, indicating that SA induces cell cycle progression. Kinetic analysis also suggested that SA stimulates only a fraction of the DNA replication in BALB/c3T3 cells. At high cell densities, SA-induced G1 cyclin expression and DNA synthesis were more strongly inhibited than those induced by FGF-1. SA did not induce cell division in HUVE and BALB/c3T3 cells and did not interfere with FGF-1-stimulated proliferation of HUVE cells. These results indicate that SA is able to partially induce cell cycle progression through a contact-inhibition sensitive signaling pathway, but it is insufficient to support cell mitosis. We also suggest that signaling by SA does not interfere with that of FGF-1.     

Mathematical modeling of turbulent combustion of hydrogen in a boundary layer

Turbulent flow in a boundary layer with injection of hydrogen through a permeable plate into an external air flow is modeled. To calculate turbulence characteristics the Lam-Bremhorst modification of the k-ε model is employed. Calculations are made both with and without account for the non-unity of the Lewis number. In determining the concentrations of the intermediate and end combustion products and the temperature the assumption of chemical equilibrium is made. The obtained distribution of turbulent pulsations allows the conclusion of flow laminarization under combustion conditions to be made. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 71, No. 1, pp. 86–91, January–February, 1998.     

Turbulent thermal boundary layer on a flat plate with a thermally insulated section

The influence of an initial adiabatic section on the heat transfer coefficient is studied on the assumption that the heat transfer law is expressed in the form St=A/Re _T ^**m Prⁿ. In addition, the temperature distribution on a thermally insulated wall is obtained when heat transfer occurs over the initial section.