A particle swarm optimization algorithm for minimizing makespan of nonidentical parallel batch processing machines

This research is motivated by our interactions with an electronics manufacturer who assembles and tests printed circuit boards (PCBs) used in consumer products. Environmental stress screening (ESS) chambers are commonly used to test PCBs to detect early failures before they are used in the field. The chambers are capable of testing multiple PCBs simultaneously (i.e., batch processing machines). The minimum testing time of each PCB and their size are known. The objective is to group these PCBs into batches and schedule the batches formed on ESS chambers such that the makespan is minimized. The ESS chambers can process a batch of jobs as long as its capacity is not violated. Each ESS chamber is unique with respect to its capacity. The problem is NP-hard. Consequently, a particle swarm optimization (PSO) algorithm is proposed. The effectiveness of the PSO algorithm is evaluated by comparing its results to a random-key genetic algorithm and a commercial solver used to solve a mixed-integer linear program. A thorough experimental study conducted indicates that the PSO algorithm reports better quality solution in a short time on larger problem instances.     

Light and transmission electron microscopic structure of skin glands and dermal scales of a caecilian amphibian Gegeneophis ramaswamii,with a note on antimicrobial property of skin gland secretion

Amphibian skin secretions contain a variety of bioactive compounds that are involved in diverse roles such as communication, homeostasis, defence against predators, pathogens, and so on. Especially, the caecilian amphibians possess numerous cutaneous glands that produce the secretory material, which facilitate survival in their harsh subterranean environment. Inspite of the fact that India has a fairly abundant distribution of caecilian amphibians, there has hardly been any study on their skin and its secretion. Herein, we describe, using light microscopy and electron microscopy, two types of dermal glands, mucous and granular, in Gegeneophis ramaswamii. The mucous glands are filled with mucous materials. The mucous‐producing cells are located near the periphery. The granular glands are surrounded by myoepithelial cells. A large number of granules of different sizes are present in the lumen of the granular gland. The granule‐producing cells are present near the myoepithelial lining of the gland. There are small flat disk‐like dermal scales in pockets in the transverse ridges of the posterior region of the body. Each pocket contains 1–4 scales of various sizes. Scanning electron microscopic (SEM) study of the skin surface showed numerous funnel‐shaped glandular openings. The antibacterial activity of the skin secretions was revealed in the test against Escherichia coli, Klebsiella pneumoniae, and Aeromonas hydrophila, all gram‐negative bacteria. SEM analyses confirm the membrane damage in bacterial cells on exposure to skin secretions of G. ramaswamii.     

Enzyme-linked immunosorbent assay (ELISA) for the determination of the toxic glycoside cleistanthin B

Cleistanthus collinus is a highly toxic plant frequently implicated in suicidal and homicidal poisoning cases referred to our laboratory. An enzyme-linked immunosorbent assay (ELISA) is reported in this paper for the quantitation of the active principles of C. collinus. This method is highly reproducible and sensitive to detect as low as 2 ng/ml of cleistanthin B, a toxic constituent of C. collinus. The ELISA can be successfully applied for the specific identification of C. collinus poisoning in clinical and forensic toxicology.     

A 600-MHz VLIW DSP

A 600-MHz VLIW digital signal processor (DSP) delivers 4800 MIPS, 2400 (16 b) or 4800 (8 b) million multiply accumulates (MMACs) at 0.3 mW/MMAC (16 b). The chip has 64M transistors and dissipates 719 mW at 600 MHz and 1.2 V, and 200 mW at 300 MHz and 0.9 V. It has an eight-way VLIW DSP core, a two-level memory system, and an I/O bandwidth of 2.4 GB/s. The chip integrates a c64X DSP core with Viterbi and turbo decoders. Architectural and circuit design approaches to achieve high performance and low power using a semi-custom standard cell methodology, while maintaining backward compatibility, are described. The chip is implemented in a 0.13-/spl mu/m CMOS process with six layers of copper interconnect.     

Equilibrium swelling properties of a novel ethylenediaminetetraacetic dianhydride (EDTAD)-modified soy protein hydrogel

A novel pH and ionic strength-sensitive protein-based hydrogel was synthesized via cross-linking ethylenediaminetetraacetic dianhydride-modified soy protein isolate (EDTAD–SPI) with glutaraldehyde. Incorporation of ionizable carboxyl groups into soy proteins increased the net negative charge of the protein and caused extensive unfolding of the protein structure. The EDTAD–SPI hydrogel was capable of imbibing 80-300 g water per g dry gel after centrifuging at 214g, depending on the extent of modification, protein structure, crosslinking density, protein concentration during the crosslinking step, gel particle size, and environ-mental conditions, such as temperature, pH, and ionic strength. The protein concentration used during the crosslinking step was found to be the most important factor affecting the water uptake of the gel. The lower the protein concentration, the higher was the water uptake at 214g. The hydrogel was highly sensitive to pH and exhibited reversible swelling when sequentially exposed to water and 0.15M NaCl. © 1996 John Wiley & Sons, Inc.     

Relaxor Behavior in Ordered Lead Magnesium Niobate (PbMg1/3Nb2/3O3) Thin Films

The local compositional heterogeneity associated with the short‐range ordering of Mg and Nb in PbMg_1/3Nb_2/3O₃ (PMN) is correlated with its characteristic relaxor ferroelectric behavior. Fully ordered PMN is not prepared as a bulk material. This work examines the relaxor behavior in PMN thin films grown at temperatures below 1073 K by artificially reducing the degree of disorder via synthesis of heterostructures with alternate layers of Pb(Mg_2/3Nb_1/3)O₃ and PbNbO₃, as suggested by the random‐site model. 100 nm thick, phase‐pure films are grown epitaxially on (111) SrTiO₃ substrates using alternate target timed pulsed‐laser deposition of Pb(Mg_2/3Nb_1/3)O₃ and PbNbO₃ targets with 20% excess Pb. Selected area electron diffraction confirms the emergence of (1/2, 1/2, 1/2) superlattice spots with randomly distributed ordered domains as large as ≈150 nm. These heterostructures exhibit a dielectric constant of 800, loss tangents of ≈0.03 and 2× remanent polarization of ≈11 µC cm^?2 at room temperature. Polarization–electric field hysteresis loops, Rayleigh data, and optical second‐harmonic generation measurements are consistent with the development of ferroelectric domains below 140 K. Temperature‐dependent permittivity measurements demonstrate reduced frequency dispersion compared to short range ordered PMN films. This work suggests a continuum between normal and relaxor ferroelectric behavior in the engineered PMN thin films.     

Implementing 0201s On High-Density Lead-Free Memory Modules

The introduction of 0201 components is another step taken in the world of electronics to aid the miniaturization of electronic products. Capacitors and resistors are now being produced in a 0201 package size; in dimensions, it means a length of 0.02 in and a width of 0.01 in. The assembly of miniature components on printed circuit boards (PCBs) poses numerous process challenges. Legislative measures to eliminate the usage of lead from electronics products compel electronics manufacturers to implement lead-free assembly. This mandates the use of lead-free 0201 components and a lead-free soldering process. The current research focuses on high-density lead-free memory module assemblies using a 1.27-mm-thick organic solderability preservative (OSP)-coated boards. The spacing between components is as low as 0.25 mm. The objective of this research is to develop a robust assembly process for lead-free 0201 components used in memory modules. The stencil, PCB land pattern designs, solder paste printing, component placement, and reflow soldering processes were studied. The process and design changes required for achieving a robust manufacturing process for assembling lead-free 0201 components on high-density assemblies have been identified and reported.     

Prescribing the Content and Timing of Product Upgrades

Demand for a family of high-technology products such as notebook computers erodes over time as competitors introduce new products that incorporate improved technologies. A manufacturer may compensate for this by applying the model formulated in this paper to prescribe the content and timing of upgrades to maximize total profit over the life cycle of the product family. The model deals with economies of scale that might be achieved by the upgrading process. It provides decision support by integrating decisions of relevant organizations in the enterprise: marketing (e.g., marketing strategy, pricing), product design engineering, process design engineering, and supply chain management (e.g., suppliers, production, outsourcing, inventory, backorders, and distribution). The paper presents a branch-and-price solution approach that employs an effective, new method for solving associated subproblems. Computations evaluate the efficacy of the solution approach and examples demonstrate contexts in which managers might apply the model to advantage.     

Hidden monosomy 7 in acute myeloid leukemia and myelodysplastic syndrome detected by interphase fluorescence in situ hybridization

Fifty patients [25 acute myeloid leukemia (AML) and 25 myelodysplastic syndrome (MDS)], without monosomy 7 according to conventional cytogenetics, were re-examined by fluorescence in situ hybridization (FISH). Eleven (44.0%) patients with AML and nine (36.0%) with MDS showed hidden monosomy 7. Two samples who had both monosomy 7 and iso chromosome 17 were analyzed by dual color FISH to identify their clonal origin, and showed that these two abnormalities can occur together or independently. Only one of 16 MDS patients without monosomy 7 transformed into AML whereas four of eight MDS patients with the hidden monosomy 7 transformed into AML, suggesting patients with this abnormality are more likely to undergo transformation to AML.