On Traveling Wave Fronts in a Bacterial Growth Model with Density-Dependent Diffusion and Chemotaxis

Bacterial colonies often generate patterns that are characterized by fingerlike projections growing out of the propagating front. In this paper, we analyze the traveling wave fronts in bacterial growth model that accounts for chemotactic movement as well as random motion in density-dependent diffusion. Specifically, the existence of traveling wave solutions to model equations is examined by means of methods of local linear and nonlinear analysis, and numerical simulations. The occurrence is shown of both sharp and smooth traveling wave fronts.     

Numerical study of dynamic thermal conductivity of nanofluid in the forced convective heat transfer

In this work, forced convective heat transfer of nanofluid in the developing laminar flow (entrance region) in a circular tube is considered. The nanofluid thermal conductivity, as an important parameter, is considered as two parts: static and dynamic part. Simulated results show that the dynamic part of nanofluid thermal conductivity due to the Brownian motion has a minor effect on the heat transfer coefficients, on the other hand, static part of thermal conductivity including nanolayer around nanoparticle has an important role in heat transfer.     

Dipeptide Analogues: Synthesis of C-Terminal p-Nitrobenzyl-3-ketoesters of N-Protected Amino Acids

Nitrogen protected amino acid imidazolides undergo facile carbon acylation with magnesium p-nitrobenzylmalonate dihydrate in THF to give pseudodipeptides in 30-79% isolated yield.     

Identities for Sums of a q-Analogue of Polylogarithm Functions

A q-analogue of the polylogarithm function is introduced via a consideration of the spectral zeta-function of the quantum group SU _q (2). We derive certain identities for linear and non-linear combinations of the q-analogue of polylogarithm functions with negative exponents.     

An Alternative Mechanism of Non-contact Anterior Cruciate Ligament Injury During Jump-landing: In-vitro Simulation

In the United States, an estimated 100,000 anterior cruciate ligament (ACL) injuries occur every year. Despite decades of research, to this date, the mechanism or mechanisms of non-contact ACL injuries are not well understood. This is primarily because trials cannot be conducted on live subjects to understand the injury mechanism, and it is difficult to instrument a live human knee to measure the response of tissues during dynamic activities. In this paper, we present a dynamic knee injury simulator capable of in-vitro modeling of the ACL injury during jump-landing activity. This system was used to simulate jump-landing on cadaveric knees and to successfully test which conditions would result in isolated ACL injury. A restricted flexion of the hip (a hip that flexes minimally or not at all during landing), combined with low quadriceps and hamstring force levels during landing were found to be conducive to ACL injury. Elevated levels of quadriceps force prevented the injury from occurring even under restricted hip flexion conditions. The measured strain rates in the ACL tissue during injury causing activities were over 250%/s.     

Nonsimilar solutions for free convection from a vertical plate in porous media

A nonsimilar boundary layer analysis has been presented for the free convection along a vertical plate embedded in a fluid-saturated porous medium in the presence of surface mass transfer and internal heat generation. The transformed conservation laws are solved numerically for the cases of variable wall temperature and variable wall heat flux boundary conditions. Results are presented for the details of the velocity and temperature fields as well as Nusselt number. Received on 13 December 1996     

Identification of Single-Particle Configurations at Very High Spin in Some Rare-Earth Nuclei

The nuclear behaviour at high angular momenta is studied by γ-rays emitted in (HI, Xn) reaction. The study of very-high spin states in ¹⁵³Ho via discrete-line γ-ray spectroscopy and a comparison between the partial decay schemes of ¹⁵³Ho and the neighbouring ¹⁵²Dy and ¹⁵⁴Er nuclei are discussed in the context of the high spin structure. Second, we present comments on some phenomena observed at high spin states in ¹⁵³Ho and ¹⁵²Dy nuclei.     

Mixed Convection-Radiation in Power-Law Fluids Along a NOn-Isothermal Wedge in a Porous Medium with Variable Permeability

A boundary layer analysis has been presented for the interaction of mixed convection with thermal radiation in laminar boundary flow from a vertical wedge in a porous medium saturated with a power-law type non-Newtonian incorporating the variation of permeability and thermal conductivity. The transformed conservation laws are solved numerically for the case of variable surface temperature conditions. The combined convection non-similar parameter we note that =0 and 1 correspond to pure free and forced convection cases. The Rosseland approximation is used to describe the radiative heat flux in energy equation. Velocity and temperature profiles as well as the local Nusselt number are presented.     

Pressure drop in alternating curved tubes

Pressure drop measurements in the laminar and turbulent regions for water flowing through an alternating curved circular tube (x=h sin 2πz/λ) are presented. Using the minimum radius of curvature of this curved tube in place of that of the toroidally curved one in calculating the Dean number (ND=Re(D/2R _c )², it is found that the resulting Dean number can help in characterizing this flow. Also, the ratio between the height and length of the tube waves which represents the degree of waveness affects significantly the pressure drop and the transition Dean number. The following correlations have been found:

1. For laminar flow: $$F_w \left( {\frac{{2R_c }}{D}} \right)^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} = F_s \left( {\frac{{2R_c }}{D}} \right)^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} + 0.03,\operatorname{Re}< 2000.$$
2. For turbulent flow: $$F_w \left( {\frac{{2R_c }}{D}} \right)^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} = F_s \left( {\frac{{2R_c }}{D}} \right)^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} + 0.005,2000< \operatorname{Re}< 15000.$$
3. The transition Dean number: $$ND_{crit} = 5.012 \times 10^3 \left( {\frac{D}{{2R}}} \right)^{2.1} ,0.0111< {D \mathord{\left/ {\vphantom {D {2R_c }}} \right. \kern-\nulldelimiterspace} {2R_c }}< 0.71.$$