Review on Metal-Filled Plastics. Part1. Electrical Conductivity

Plastic composites are members of both the oldest and the newest of materials. The first reinforced polymeric-based materials are recorded in Genesis and Exodus in the Bible as being used by the people of Babylonia and Mesopotamia around 4000–2000 B.C. These materials consisted of bitumen-based pitch for building products and bundles of papyrus reed embedded in a bitumen matrix for the construction of river boats [1]. The Hindu Vedas (written about 1000 B.C.) refers to the use of lac (a complex polymeric substance consisting of polyether and polyester chains) with fine sand for the manufacture of whetstones, which were known in India and China for several thousand years. There are a number of examples that could date back the origin of polymer composites into antiquity [1–3]. but the science of enhancing the properties of polymeric composites by the use of suitable fillers has been practiced extensively not earlier than the beginning of this century. For example, the tensile strength of polystyrene was modified by the incorporation of glass fillers only in the 1950s, half a century later than that predicted by Backeland in the early 1900s [2]. Carbon black is known to be a potential reinforcement for rubber for over 50 years. Although glass bead and glass fibers have been known for centuries, the use of these economical products in the plastic industry is relatively new [2].     

Synthesis,characterization and application of biopolymer-ionic liquid composite membranes

Biopolymer composite membranes based on chitosan doped with an ionic liquid (IL) 1-ethyl 3-methylimidazolium thiocyanate (EMImSCN) have been developed and characterized. The doped ionic liquid films show remarkable enhancement in ionic conductivity (σ). The Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM) and X-ray diffraction studies (XRD) affirmed the composite nature, good incorporation of ionic liquid and reduction in crystallinity of films, respectively. The interaction between ionic liquid, chitosan and iodide polymer electrolyte matrix was evaluated by cyclic voltammetry. The fabricated dye sensitized solar cell (DSSC) using this new biopolymer electrolyte membranes shows promising performance.     

On the Dempster-Shafer evidence theory and non-hierarchicalaggregation of belief structures

The Dempster's rule of combination is a widely used technique to integrate evidence collected from different sources. In this paper, it is shown that the values of certain functions defined on a family of belief structures decrease (by scale factors depending on the degree of conflict) when the belief structures are combined according to the Dempster's rule. Similar results also hold when an arbitrary belief structure is prioritized while computing the combination. Furthermore, the length of the belief-plausibility interval is decreased during a nonhierarchical aggregation of belief structures. Several types of inheritance networks are also proposed each of which allows considerable flexibility in the choice of prioritization     

A simple method for measuring the dielectric constant of solids

This paper presents a simple method for determining the dielectric constant of a solid material. The method consists of measuring the return loss due to a slab of such material inserted into a rectangular waveguide. The dielectric slab presents a discontinuity inside the waveguide, and the electric field at each interface of the slab is described as a summation of weighted sinusoidal basis functions. The scattered magnetic field on either side of the slab is determined using the modal expansion approach. These weights are solved by using the method of moments on the boundary conditions of continuity of the tangential magnetic field at the interfaces. The component of the electric field (scattered) for the dominant TE₁₀ mode can then be determined in terms of these weights, and from this result the reflection coefficient can be theoretically evaluated. A comparison between the experimentally obtained reflection/transmission coefficient and the theoretical values provide a figure for the dielectric constant of the material     

Integration of a modulated barrier photodiode with a doped-channelquasi-MISFET

An integration scheme for a front-end photoreceiver is demonstrated, wherein an identical GaAs-InGaAs-AlGaAs heterostructure is used for realizing a modulated barrier photodiode (MBP) and a doped-channel quasi-MISFET. The detectors exhibit optical gains of 200. The FETs have an extrinsic transconductance of 250 mS/mm, with f_f=12 GHz and f_max=21 GHz     

The comparative performance of some finite difference equations for transient heat conduction

The established finite difference equations to estimate one-dimensional transient heat flow in solids are the ‘classical’ form (explicit), and the Crank–Nicolson and ‘pure-implicit’ forms (both implicit). They are all based on finite difference approximation to the Fourier continuity equation. To these are now added three more explicit forms: exponential linear, exponential inverse cosine and polynomial, which are based on exact solutions to the Fourier equation. The performance of each of the six equations is tested against the exact results of a well known step excitations problem (the Groeber model). The tests consist of examining (i) finite difference errors arising from a single implementation of each form at different stages in the transient cooling process, (ii) the errors that accumulate during part or all of the cooling process (both as regards any bias that is introduced, and also a measure of variance) and (iii) the run times in executing the various forms. The nondimensional time step r was treated as the independent variable, and can be made arbitrarily large, by use of a simple time-division procedure (otherwise r < ½ for use with the classical form). It is shown that having regard to both error and run time, the polynomial form appears to be the most efficient estimator.     

High-level test generation for VLSI

The authors survey high-level approaches to test generation for VLSI circuits, which can significantly reduce test generation time while still providing good fault coverage. High-level approaches view the circuit with less structural detail, that is, from a more abstract viewpoint and often hierarchically. The authors first review some basic circuit and fault models and the two most widely known test-generation algorithms as a basis for comparison between high-level and low-level techniques. The authors then examine the more important high-level approaches, which fall into two broad classes, namely algorithmic and heuristic     

Deep fat frying characteristics of chickpea flour suspensions

Chickpea ( Cicer arietinum ) (Bengal gram) flour suspensions are widely used in the preparation of oriental traditional snacks and sweets. We investigated the frying characteristics of small and large boondi , a traditional product made by deep fat frying the droplets of chickpea flour suspensions. The rate of water loss during frying was much higher than that of oil uptake. Towards the end of frying, the bulk densities of small and large boondis were similar and remained constant. The analysis of microstructure of the product indicated that there were large pores and vacuoles inside, whereas the outer surface remained fairly smooth with fewer smaller pores. The colour changes during frying were described in terms of tristimulus values (brightness, hue and chroma) and yellowness, of which brightness decreased markedly; the colour of the product changed from bright yellowish orange (raw batter) to dull orange (finished product).