Effective Intermolecular Interaction Potentials of Gaseous Fluorine,Chlorine, Bromine,and Iodine

Results are presented for binary intermolecular interactions and thermophysical properties in the temperature range between 70K and 1,000K of gaseous fluorine (F₂), and between 200K and 1,000K of chlorine (Cl₂), bromine (Br₂), and iodine (I₂). Our studies are carried out with an (n − 6) Lennard-Jones temperature-dependent potential (LJTDP). The underlying model takes into account the influence of vibrational excitations on the equilibrium distance R _m(T) and potential well depth e(T){\varepsilon(T)} . The potential parameters at T = 0K have been obtained by minimization of the sum of squared deviations between experimentally determined and calculated second pVT- and acoustic virial coefficients, B and β, and viscosities η, normalized to their relative experimental error a _exp. The majority of the available experimental data are well reproduced within their experimental errors. Tables and fitting formulae for a fast and reliable prediction of the thermophysical properties and potential parameters are also presented.     

Target Costing für Werkstoffe – Potenziale und Methodik

Target Costing for Materials – Potentialities and Methodology Target Costing is a standard instrument of cost management in business administration, but hardly mentioned in the economic oriented literature on material sciences. Nevertheless there are high potentialities for developers, producers, or users of materials regarding the improvement of efficiency. Therefore, this article will present these potentialities of a material oriented Target Costing. Besides, the general methodology of Target Costing will be modified to meet the specifics of materials from the perspectives of users of materials on the one hand and developers respectively producers of materials on the other.     

Analysis of Slip Behavior in a Single Shear Lap Lead-Free Solder Joint During Simple Shear at 25°C and 0.1/s

The relative activity of the potential slip systems in Sn is examined by comparing an experiment of a single shear lap deformation with simulations using the viscoplastic self-consistent crystal plasticity model developed by Lebensohn and Tomé. In a single shear lap specimen made using eutectic Sn-Ag solder on copper pull tabs, the initially polished side was characterized using orientation mapping before and after 0.8 shear deformation at 25°C at a shear strain rate of 0.1/s. The critical resolved shear stress of potential slip systems and the rate sensitivity was altered by trial and error until good agreement between experimentally observed and computed texture was obtained. This result indicated that slip on {101) and {211) planes is much more difficult to activate than on other slip systems for the grain orientations present in this sample. This particular sample showed much activity on the {010)〈101] slip system, but the activation of this slip system may be related to the initial dominant orientation in the specimen. This result is compared with literature and related experiments on ball grid arrays in a companion paper in this volume that show similar trends. As lead-free solder joints are commonly single crystals or multicrystals, this particular result is not indicative of lead-free solder joints as a whole, but must be interpreted in the context of a larger data set.     

Modeling of concrete behavior under high strain rates with inertially retarded damage

The paper proposes a novel approach to model the influence of high strain rates on the behavior of quasi-brittle materials like concrete. It is based on gradient continuum damage, where the gradient part is extended with an inertia of damage. This causes a retardation of damage due to the fact that micro-cracks cannot spread out arbitrarily fast. The application is demonstrated with uniaxial tensile wave propagation and for a plane stress case. Increasing strain rates lead to an expansion of the linear stress–strain behavior with stresses exceeding the quasistatic material strength.     

Plastic collapse analysis of thin-walled circular tubes subjected to bending

Circular tubes have been widely used as structural members in many engineering applications. Therefore, its collapse behavior has been studied for many decades, focusing on its energy absorption characteristics and collapse mechanism. In order to predict the collapse behavior of members, one could rely on the use of finite element codes or experiments. These tools are helpful and have high accuracy but are costly and require extensive running time. Therefore, an approximate model of tubes collapse mechanism is an alternative especially for the early step of design. This paper is also aimed to develop a closed-form solution to predict the moment–rotation response of circular tube subjected to pure bending. The model was derived based on the principle of energy rate conservation. The collapse mechanism was divided into three phases. New analytical model of ovalisation plateau in phase 2 was derived to determine the ultimate moment. In phase 3, the Elchalakani et al. model [Int. J. Mech. Sci. 2002; 44:1117–1143] was developed to include the rate of energy dissipation on rolling hinge in the circumferential direction. The 3-D geometrical collapse mechanism was analyzed by adding the oblique hinge lines along the longitudinal tube within the length of the plastically deformed zone. Then, the rates of internal energy dissipation were calculated for each of the hinge lines which were defined in terms of velocity field. Inextensional deformation and perfect plastic material behavior were assumed in the derivation of deformation energy rate. In order to compare, the experiment was conducted with a number of tubes having various D/t ratios. Good agreement was found between the theoretical prediction and experimental results.     

Aging and fatigue in bulk ferroelectric perovskite ceramics

Abstract

The aging of dielectric, elastic and piezoelectric properties is caused by a reduction of the 90° domain wall mobility. Defect dipoles in the domains orient slowly in energetically preferred directions. The oriented defects increase the force constant for the reversible domain wall displacement by electric or elastic fields. Observations of fatigue in bulk materials are briefly discussed.     

Glass‐polymer melt hybrids. I: Viscoelastic properties of novel affordable organic‐inorganic polymer hybrids

A novel class of organic‐inorganic polymer hybrids was developed by melt‐blending up to 50 (v/v) % [about 83 (w/w) %] tin‐based polyphosphate glass (Pglass) and low‐density polyethylene (LDPE) in conventional plastics processing equipment. The liquid‐ and solid‐state rheology of the polymer hybrids was studied under oscillatory shear flow and deformation to understand the behavior of these materials and to accelerate efforts to melt process the Pglass with organic polymers. All the materials were found to be linearly viscoelastic in the range of temperature and frequencies examined and their viscoelastic functions increased with increasing Pglass concentration. The Pglass significantly enhanced the shear‐thinning characteristics of the Pglass‐LDPE hybrid, indicating the presence of nonlinear chemical and physical interactions between the hybrid components. Morphological examination of the materials by scanning electron microscopy revealed interesting evolution of microstructure of the Pglass phase from droplets (or round beads) to elongated and interpenetrating network structures as the glass concentration was increased in the Pglass‐LDPE hybrids. Melt viscosities of the materials were well described by a simple power‐law equation and a Maxwellian (Hookean) model with three relaxation times. Time‐temperature superpositioning (TTS) of the complex viscosity versus frequency data was excellent at 170°C < T < 220°C and the temperature dependencies of the shift factors conformed excellently well to predictions from an Arrhenius‐type relation, enabling calculation of the flow‐activation energies (25–285 kj/mol) for the materials. The beneficial function of the Pglass in the hybrid system was significantly enhanced by pre‐treating the glass with coupling agents prior to incorporating them into the Pglass‐LDPE hybrids.     

Stabilization in the ZaP Flow Z-Pinch

The ZaP flow Z-pinch experiment at the University of Washington investigates the innovative plasma confinement concept of using sheared flows to stabilize an otherwise unstable configuration. The ZaP experiment generates an axially flowing Z-pinch that is 1 m long with a 1 cm radius with a coaxial accelerator coupled to a pinch assembly chamber. Magnetic probes measure the fluctuation levels of the azimuthal modes m = 1, 2, and 3. After assembly, the plasma is magnetically confined for an extended quiescent period where the mode activity is significantly reduced. Experimental measurements show a sheared flow profile that is coincident with the low magnetic fluctuations during the quiescent period. Recent experimental modifications produce more energetic Z-pinch plasmas that exhibit the same general behavior. The plasma equilibrium is characterized with a suite of diagnostics that measure the plasma density, magnetic field, ion and electron temperatures, in addition to plasma flow. The equilibrium is shown to satisfy radial force balance.     

Thermovoltaic processes in gallium arsenide doped with tin

In this study, we present the results of studies of n-GaAs??Sn?? with simple ohmic contacts in the temperature range of 30?C200°C. It was found that, at temperature T > 30°C, this structure generates current (up to 0.018 ??A) and voltage (up to 1.2 mV) and also has rectifying properties.     

Mass transfer from outer surface of thin tubes in parallel turbulent flow

The mass transfer coefficients from the outer surface of tubes or cylinders held in parallel turbulent steams have been calculated using integral momentum and mass transfer equations. The solution uses a hydrodynamics independent constant, λ _c which depends only upon Schmidt number. The results exhibit significant effect of curvature. For Schmidt number less than 108, Sherwood number can be predicted by $Sh_d Sc^{ - 1/3} = 0.039Sc^{0.208} \times \left( {\frac{L} {d}} \right)^\alpha \operatorname{Re} _d^{0.8}$Sh_d Sc^{ - 1/3} = 0.039Sc^{0.208} \times \left( {\frac{L} {d}} \right)^\alpha \operatorname{Re} _d^{0.8}, where α = −0.169Sc^−0.0103. The effect of the curvature is insignificant where $\frac{L} {d}\operatorname{Re} _L^{ - 0.2} - 0.033 \times \ln (Sc) \leqslant 0.214$\frac{L} {d}\operatorname{Re} _L^{ - 0.2} - 0.033 \times \ln (Sc) \leqslant 0.214.