Bioenergy from rice crop residues: role in developing economies

Energy demands of industry, agriculture, transport and domestic sectors of a developing nation are primarily in terms of electricity and transportation fuel. Rice is a major crop in many developing countries. The residues of this crop, viz. rice husk, and rice straw have high potential for bioenergy generation. This review article tries to explore potential of this bio-resource and emphasizes its effective utilization for energy production through techno-economic analysis. The structure, properties, and treatment of rice crop residues have been described. A literature review in production of various biofuels through thermo-chemical and biochemical conversion of rice straw and husk has been presented. Finally, brief literature review on economic analysis of production of liquid and gaseous biofuels from rice crop residues through biochemical and thermo-chemical routes has been presented. This analysis reveals that production of different biofuels from rice crop residues is economically viable. This review emphasizes that bioenergy from rice crop residues provides simultaneous solution to issues of energy security and climate change risk in developing nations.     

Eudragit S100 coated microsponges for Colon targeting of prednisolone

Context: Microsponge is a novel approach for targeting the drug to the colon for the management of colon ailments such as inflammatory bowel disease.

Objective: Prednisolone loaded microsponges (PLMs) were prepared and coated with Eudragit S 100 (ES) and evaluated for colon-specific drug delivery.

Materials and methods: PLMs were prepared using quasi emulsion solvent diffusion technique using ethyl cellulose, triethylcitrate (1% v/v, plasticizer) and polyvinyl alcohol (Mol. Wt. 72?kDa, emulsifying agent). The developed microsponges were compressed into tablets via direct compression technique using sodium carboxymethyl cellulose (Na CMC) and magnesium stearate as super-disintegrant and lubricant, respectively. The tablets were then coated with ES to provide protection against harsh gastric environment and manifest colon-specific drug release.

Results: PLMs were found to be nano-porous spherical microstructures with size around 35?µm and 86% drug encapsulation efficiency. Finally, they were compressed into tablets which were coated with Eudragit S 100 In vitro drug release from ES coated tablets was carried out at various simulated gastrointestinal fluids i.e. 1?hr in SGF (pH 1.2), 2 to 3?h in SIF (pH 4.6), 4–5?h in SIF (pH 6.8), and 6–24?h in SCF (pH 7.4) and the results showed the biphasic release pattern indicating prolonged release for about 24?h.

Discussion and conclusion: In vitro drug release studies revealed that drug starts releasing after 5?h by the time PLMs may enter into the proximal colon. Hence maximum amount of drug could be released in the colon that may result in reduction in dose and dose frequency as well as side effects of drug as observed with the conventional dosage form of prednisolone.     

Two-layered micropolar fluid flow through stenosed artery: Effect of peripheral layer thickness

An unsteady analysis of a two-layered blood flow through a flexible artery under stenotic conditions has been carried out in the present study where the flowing blood is represented by the two-fluid model, consisting of a core region of suspension of all erythrocytes assumed to be Eringen’s micropolar fluid and a plasma layer free from cells of any kind as a Newtonian fluid. The artery has been treated as an elastic (moving wall) cylindrical tube. The equations governing the unsteady flow mechanism subject to pulsatile pressure gradient, has been solved numerically using finite difference scheme by exploiting the appropriate physically realistic prescribed conditions. An extensive quantitative analysis has been performed through numerical computations in order to estimate the effect of different micropolar fluid parameters and the Reynolds number on the flow velocity, the flux, the resistive impedance and the wall shear stress together with their dependencies with time, the input pressure gradient and the severity of the stenosis. The graphical representations of these results do illustrate the flow characteristics of blood under stenotic conditions with proper scientific reasoning and hence validate the applicability of the model under consideration. Special emphasis has duly been made to compare the present theoretical results with the existing ones including experimental results and good agreement between them has been achieved both qualitatively and quantitatively.     

Doping-induced coloration in titania

Thermal decomposition of Ti₃GeC₂ MAX phase at 1773 K yields an orange-colored titania powder. Micro-XRD of the powder under oscillation mode reveals a pure rutile phase (space group P42/mnm). X-ray photoelectron spectroscopy confirmed substitutional doping of Ge in the titania lattice. The presence of Ti-O-Ge bond was observed in O 1s spectrum and confirmed by the shift in binding energy in Ti 2p_3/2 and Ge 3d peaks. The UV-visible Diffuse Reflectance Spectrum studies on the Ge-doped titania powder show wide absorption in the visible region (380 to 650 nm) yielding a bandgap of 2.83 eV, which is desirable for photocatalytic applications. Defect states formed due to Ge doping led to lowering of the titania conduction band inducing an orange coloration in the powder.     

A Layered Finite Element Method for Electromagnetic Analysis of Large-Scale High-Frequency Integrated Circuits

A high-capacity electromagnetic solution, layered finite element method, is proposed for high-frequency modeling of large-scale three-dimensional on-chip circuits. In this method, first, the matrix system of the original 3-D problem is reduced to that of 2-D layers. Second, the matrix system of 2-D layers is further reduced to that of a single layer. Third, an algorithm of logarithmic complexity is proposed to further speed up the analysis. In addition, an excitation and extraction technique is developed to limit the field unknowns needed for the final circuit extraction to a single layer only, as well as keep the right-hand side intact during the matrix reduction process. The entire procedure is numerically rigorous without making any theoretical approximation. The computational complexity only involves solving a single layer irrespective of the original problem size. Hence, the proposed method is equipped with a high capacity to solve large-scale IC problems. The proposed method was used to simulate a set of large-scale interconnect structures that were fabricated on a test chip using conventional Si processing techniques. Excellent agreement with the measured data has been observed from dc to 50 GHz     

The effect of surface modification on fretting fatigue in Ti Alloy turbine components

Severe fretting damage has been observed on the pressure surfaces of fan and compressor blade dovetails/disks in an aerospace gas turbine engine. A study has been carried out to evaluate the effect of an ion implantation technique in combination with the presently used surface treatments, such as shot peening and coating, on the fretting fatigue life of titanium alloy gas turbine engine components. The results from fretting fatigue tests, residual stress measurements, and nanoindentation tests were used to quantitatively evaluate the effect of various surface treatments on the fretting fatigue life of the fan blade and disk materials. Results from microstructural characterization and analyses of elemental and phase distributions within the implanted region are used to understand the effect of ion implantation on the surface properties of the alloys. Finally, an attempt has been made to evaluate the potential for improving the fretting fatigue life of the engine components using various surface modification techniques.     

Algorithms to select I DDQ measurement points to detect bridging faults

I _DDQ measurement is a time consuming process. Thus, reducing the number of I _DDQ measurements have a great impact on the test time. Carefully selecting a few I _DDQ measurement points is therefore an important problem. This problem has been studied for detecting leakage faults but not for bridging faults. We present novel algorithms to select I _DDQ measurement points to detect bridging faults. Experimental results obtained are very encouraging. The method can also be used: by test generators to compress I _DDQ test sets; and to maximize the fault coverage when a fixed number of measurement points are given.Research supported by NSF Grant No. MIP-9102509.     

The kinetics of hydrodesulphurisation of thiophene over a Cobalt-molybdenum catalyst

Hydrogenolysis of thiophene in naphtha has been investigated over a series of unsupported and γ-alumina-supported cobalt-molybdenum catalysts at atmospheric pressure using a fixed-bed microreactor. A kinetic expression describing the effects of temperature and space velocity was verified experimentally. The hydrogenolysis of thiophene was found to be 0.8th-order with respect to thiophene and first-order with respect to hydrogen. The activation energy of the reaction over cobalt-molybdenum (Co₃O₄—MoO₃ weight ratio 25:75) catalysts was found to be 27.5 kJ mol^?1. X-ray analysis of the various cobalt oxide-molybdenum oxide catalysts shows that MoS₂ or MoO₂ + MoS₂ may be the catalytic agent in this reaction.     

Production Scheduling During Phased Implementation of Flexible Manufacturing Cells

Introduction of a new manufacturing technology is a strategic decision. The choice of a proper technology is a strategic issue but the utilization of the new technology depends on tactical and operational considerations. The costs and risks involved depend, among others, on the relative strengths of the current and new manufacturing technologies, and the way the new technology is implemented. In this paper we address strategic, tactical and operational issues as we consider a phased implementation of a Flexible Manufacturing System (FMS). Phased implementation can help by spreading the risks and costs involved over a long period of time.

The experience that management gains during the phased implementation process increases the probability of a successful introduction of the new technology. The first step in this endeavor is to introduce the new technology in the form of a Flexible Manufacturing Cell (FMC)that would operate concurrently with the existing technology. We develop a procedure that allocates work load, specified by the Master Production Schedule (MPS), to the FMC as well as the conventional shop. The next step is to introduce additional FMC's and to integrate them into an FMS. We therefore extend the analysis to the case of several identical FMC's which operate in a mixed production facility with conventional machines. Computational experience with the proposed procedures is reported along with some numerical results.     

Supporting production operations decisions with a modularized knowledge base

In expert system applications, it is often necessary to modularize large knowledge bases in such a way that only a subset of the modules is required for a problem. This results in a reduction in the search for appropriate models at each stage. Using the formalism of first order predicate calculus, we develop a modularization scheme of an inventory system which minimizes a pseudo-cost function representing the actual search process.