Particle size distribution in a wire-arc spraying system

The size and velocity of particles produced by a ValuArc 200 (Sulzer-Metco, Westbury, NY) twin-wire-arc spraying system were measured in-flight using a DPV-2000 system (Tecnar Ltd., St-Bruno, QC, Canada) for a range of operating parameters. A technique was developed to identify and separate the size distributions of particles produced by atomization of molten metal at either the anode or the cathode by assuming that both follow a log-normal distribution. It was shown that particles produced by the anode are almost two times larger in diameter than those originating from the cathode. Experiments showed that increasing the pressure of atomizing gas decreased the size of both anodic and cathodic particles, but changing wire feed rate and operating voltage did not change particle size significantly.     

Techno‐economic and environmental analysis for grid interactive solar photovoltaic power system of Lakshadweep islands

The Lakshadweep group of islands in Arabian Sea is one of the two major groups of islands in India. In these islands the main source of electricity is diesel generators, the diesel being transported from the main land to produce over 9 MW of electricity. Considering the remoteness of the island and the polluting nature of the existing plants, it is desirable to adopt a strategy to utilize available potential of non‐polluting renewable energy sources for these ecologically sensitive islands. A techno economic and environmental analysis for grid interactive solar photovoltaic power system of Union Territory of Lakshadweep islands is presented. This paper also examines the pollution aspect of power generation through Diesel Generator set and highlights the environmental benefits in using solar energy. Experiences of grid interactive solar photovoltaic power system installed recently in different islands are discussed and suggestions have been made for improving its efficiency and performance. Copyright © 2004 John Wiley & Sons, Ltd.     

Fatty Acid Conjugated Calcium Phosphate Nanoparticles for Protein Delivery

Calcium phosphate (CaP) nanoparticles with particle sizes <100 nm were prepared and conjugated with lauric acid. This was achieved by first activating the phosphate group of CaP and conjugating it with lauric acid via acid chloride route incorporating chitosan as a spacer. Insulin was loaded and the nanoparticles were coated with alginate to impart pH-dependent sustained release. The released insulin was stable without alteration of the conformation of insulin and the particles were found to be noncytotoxic. Thus these CaP nanoparticles may be used as an excellent carrier for delivering protein drugs particularly insulin orally.     

Effect of chromium on the mechanical properties of powder-processed Fe–0.45 wt.% P alloys

The present investigation shows the role of chromium in Fe–P binary and Fe–P–Cr ternary alloys. The compositions are characterized in terms of microstructure, porosity content, hardness and tensile properties. The alloys were made using a hot powder forging technique. In this process mild steel encapsulated powders were hot forged into slabs. Then the slabs were hot rolled and annealed to relieve the residual stresses. Densifications as high as 98.9% of theoretical density have been realized. Microstructures of these alloys consist of single-phase ferrite only. Both Fe–0.45P and Fe–0.45P–3Cr alloys showed very high strength. As forged and hot rolled Fe–0.45P alloy showed low elongation. It was observed that, the addition of Cr to Fe–P based alloys caused an increase in strength associated with the reduction in ductility. Alloys developed in the present investigation were capable of hot working to very thin gage of sheets and wires.     

An efficient video watermarking based security model

Microsystem Technologies - Watermarking is defined as about hiding any valuable information set in the particular digital media by itself through modifying the particular graphic contents. In our...     

Photoelectrochemical solar cells using electrodeposited GaAs and AlSb semiconductor films

Electrodeposited GaAs and AlSb thin film semiconductors were prepared under various deposition conditions. Reasonable stoichiometry could be attained as revealed by EDAX studies. The best stoichiometry was obtained are Ga_1·04As_0·96 and Al_1·12Sb_0·88. The band gap of the GaAs and AlSb films was ∼1·5 eV and 1·6 eV respectively. The electrochemical and photoelectrochemical studies on these films are reported with different redox-couples in aqueous and non-aqueous medium.     

Parallel context-sensitive compilation

The searching power of massively parallel associative computers is an under used and under investigated capability that can be used to facilitate software development. This paper describes the development of a context sensitive compiler for pattern-matching languages using that searching power. The described compiler was implemented on the STARAN parallel computer and the compiled OPS5 programs were also executed on the STARAN obtaining an estimated throughput of 6000 rules per second. The described compilation of production rules into equivalent procedural rules is completely data parallel, with the degree of parallelism depending on the number of tokens in the program being compiled. During any one step of the context-sensitive analysis, the entire program is processed in constant time.     

Improved Routh-Pade/spl acute/ approximants: a computer-aided approach

A geometric programming based computer-aided method to derive a reduced order (rth-order) approximant for a given (stable) SISO linear continuous-time system is presented. In this method, stability and the first r time moments/Markov parameters are preserved as well as the errors between a set of subsequent time moments/Markov parameters of the system and those of the model are minimized.     

Atomistic simulation of grain boundary sliding and migration

Interatomic potentials using Embedded Atom Method (EAM) are used in conjunction with molecular statics and dynamics calculations to study the sliding and migration of [1 1 0] symmetric tilt grain boundaries (STGB) in aluminum, under both applied displacement and force conditions. For equilibrium grain boundaries (without applied displacements and forces), three low energy configurations (corresponding to three twin structures) are found in the [1 1 0] STGB structures when grain boundary energies at 0 K are computed as a function of grain misorientation angle. Pure grain boundary sliding (GBS) without migration is simulated by applying external displacement. When forces are applied, the energy barriers are reduced consequent to the fact that grain boundary sliding of STGB is always coupled with migration. The propensity for pure GBS is evaluated by computing the energy associated with incremental equilibrium configurations during the sliding process and compared to the case when sliding is accompanied by migration. The magnitude of the energy barriers is found to be much higher in pure GBS than when migration accompanies sliding. Relations between the applied force, internal stress field, and displacement field are established and the role of grain boundary structure on the deformation process are examined. It is found that the GBS displacement is proportional to applied force, GB energy, and time.     

Social group optimization for global optimization of multimodal functions and data clustering problems

Neural Computing and Applications - Cost and physical constraints in the engineering applied problems obligate finding the best results that global optimization algorithms cannot realize. For...