A system for the exposure of small laboratory animals to a 25-mT60-Hz alternating or traveling magnetic field

A versatile exposure system which can be used to investigate the effects of a 60-Hz alternating magnetic field or traveling magnetic field on small laboratory animals is described. Special attention was given to the design of the electric circuit to simplify the supply requirements and to keep the overall current to a minimum. A magnetic field having a flux density up to 30 mT (300 G) can be generated, and a traveling magnetic field is obtained by reconnecting the coils to a three-phase supply. The total magnetic field due to the currents in the three coils used in the exposure system is analyzed. A computer program was written to evaluate the magnetic field in the region where the animals are located. The difference observed between measured and computed values is attributed to the representation of the multiturn, multilayer coils by equivalent single-turn coils     

Existence of solitary waves in a prestressed nonlinear thermoelastic medium with dry friction

V. I. Lenin Belorussian State University, Minsk. Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 62, No. 1, pp. 140–145, January, 1992.     

An area-efficient VLSI implementation for programmable FIR filters based on a parameterized divide and conquer approach

In this paper, we propose an optimal VLSI implementation for a class of programmable FIR filters with binary coefficients, whose architecture is based on a parameterized divide and conquer approach. The proposed design is shown to be easily extendable to FIR filters with multibit coefficients of arbitrary sign. The area efficiency achieved in comparison to direct form realization is demonstrated by VLSI implementation examples, synthesized in TSMC 0.18-μm single poly six metal layer CMOS process using state-of-art VLSI EDA tools. The possible saving in average power consumption is estimated using gate-level power analysis. Suggestions for applications and topics for further research conclude the paper.     

Flexural Behavior of Concrete-Filled Fiber-Reinforced Polymer Circular Tubes

This paper presents the experimental results of large-scale concrete-filled glass fiber reinforced polymer (GFRP) circular tubes and control hollow GFRP and steel tubes tested in bending. The diameter of the beams ranged from 89 to 942 mm and the spans ranged from 1.07 to 10.4 m. The study investigated the effects of concrete filling, cross-sectional configurations including tubes with a central hole, tube-in-tube with concrete filling in between, and different laminate structures of the GFRP tubes. The study demonstrated the benefits of concrete filling, and showed that a higher strength-to-weight ratio can be achieved by providing a central hole. The results indicated that the flexural behavior is highly dependent on the stiffness and diameter-to-thickness ratio of the tube, and, to a much less extent, on the concrete strength. Test results suggest that the contribution of concrete confinement to the flexural strength is insignificant; however, the ductility of the member is improved. A strain compatibility model has been developed, verified by the experimental results, and used to provide a parametric study of the different parameters, significantly affecting the behavior. The parametric study covered a wide range of FRP sections filled with concrete, including under-reinforced, balanced, and over-reinforced sections.     

On the Dieudonné Theorem in Reflexive Banach Spaces

The converse part of the Dieudonné theorem on the closedness of the difference of two closed convex sets is establish. It is proved that, in a reflexive Banach setting, the sufficient conditions given by Dieudonné when applied for the weak topology, are also necessary.     

The effects of long‐term exposure of flax fiber reinforced polymer to salt solution at high temperature on tensile properties

Most research on natural fiber composites has been primarily conducted on randomly‐oriented fibers. This study is focused on the short‐ and long‐term performances of flax fiber‐reinforced polymer (Flax‐FRP) made from continuous unidirectional fiber mats, and compares it to Glass‐FRP composite. The study looked into the effect of number of layers on properties, comparing wet layup (WL) to vacuum bag (VB) molding, and aging in a 3.5% salt solution for up to 365 days at 23, 40, and 55°C. Results show that Flax‐FRP has a tensile strength and modulus of one third the values of Glass‐FRP. Using the VB process, Flax‐FRP showed a strength and modulus 18 and 36% higher, respectively, than WL specimens. As the number of layers increased from one to five, the strength and modulus also increased but stabilized at three layers. After 365 days of conditioning at 23, 40, and 55°C, WL specimens showed a strength retention of 81, 73, and 69%, respectively. Using the Arrhenius relationship, it was estimated that both WL and VB Flax‐FRP would retain 60% of their tensile strength after 100 years of saltwater exposure at an annual mean temperature of 10°C. POLYM. COMPOS., 37:3234–3244, 2016. © 2015 Society of Plastics Engineers     

Some Semiconductor Properties of Carboxymethyl Cellulose-Copper Complexes

Metal chelates of three grades of carboxymethyl cellulose (CMC) (LI-L3) with Cu(II) ions, either originating from CuCl₂ or CuSO₄, were prepared and characterized by elemental analysis, infrared spectra, and electrical conductivity studies. The results showed that the degree of substitution of CMCs and the origin of the Cu(II) ion have a profound effect on the amount of metal included in the polymer complexes and the structure and the electrical conductivity of the prepared complexes. CMC acts as a uninegatively charged bidentate ligand when it is chelated with Cu(II) of CuCl₂ via the carboxymethyl group and exhibits the formula Cu(L)₂, whereas it acts as a binegatively charged bitentate ligand when it is chelated with CuSO₄ via the carboxymethyl and secondary hydroxyl groups and exhibits the formula CuL.2H₂O. The investigation revealed that the electrical conductivity depends on the temperature and has two maximum peaks. The values of the activation energy for the conductivity of CMC and their complexes indicated that the samples changed from a low-semiconductor to a high-semiconductor property with heating. It is found that CMC-Cu(II) complexes formed from CuSO₄ exhibit a high-semiconductor property compared to complexes derived from CuCl₂.