A profilometric study of levelling in electroplating

The levelling power of a plating bath is usually assessed from measurements of surface roughness (R _a or r.m.s.) before and after plating. The availability of new parameters for surface characterization now permits a better understanding of the role played by surface microgeometry in levelling. This paper explores the possibility of using these parameters for finding a reliable representation of levelling for quantitative assessment. A new measure based on the profile length parameter is suggested.     

Rate of release of spruce budworm pheromone from virgin females and synthetic lures

The rate of pheromone [(E)- and (Z)-11-tetradecenal] release from calling virginChoristoneura fumiferana females and synthetic lures was determined in both static and aerated atmospheres. In a static system ca. 2 ng/hr was recovered per female. Owing to the > 75% adsorption onto the females' bodies in static atmospheres, the actual release rate has to be corrected to roughly 9–27 ng/hr, depending on the percentage adsorbed. In the air-flow system, females were found to release between 4 and 20 ng/hr. On a 168 light-dark cycle, calling began 1–2 hr before lights-off and continued nonstop until lights-on. Pheromone was emitted throughout calling, while no pheromone was detected during the noncalling periods.Lepidoptera: Tortricidae.Published as Journal Article No. 10258 of the Michigan Agricultural Experiment Station.     

Bioceramics composition modulate resorption of human osteoclasts

Biomaterials used in bone regeneration are designed to be gradually resorbed by the osteoclast and replaced by new bone formed through osteoblastic activity. The aim of the present study is to analyze the role of osteoclasts in the resorption process. The attachment of human osteoclasts and the appearance of their resorption lacunae, when cultured on either the resorbable crystalline, calcium orthophosphate materials or on the long-term stable bioceramic material was investigated. The resorbable materials contain Ca₁₀[K,Na](PO₄)₇ (AW-Si) and Ca₂KNa(PO₄)₂ (GB14, GB9 & D9/25) as their main crystal phases, however they differ in their total solubility. These differences result from small variations in the composition. The long-term stable material consist of about 30% fluorapatite beside calcium zirconium phosphate (Ca₅(PO₄)3F + CaZr₄(PO₄)₆) and shows a very small solubility. AW-Si has an alkali containing crystalline phase, Ca₁₀[K,Na](PO₄). While GB14, GB9 and D9/25 contain the crystalline phase Ca₂KNa(PO₄)₂ with small additions of crystalline and amorphous diphosphates and/or magnesium potassium phosphate (GB14). D9/25 and AW-Si is less soluble compared to GB14, and GB9 among the resorbable materials. Resorbable and long-term stable materials vary in their chemical compositions, solubility, and surface morphology. Osteoclasts modified the surface in their attempts to resorb the materials irrespective of the differences in their physical and chemical properties. The depth and morphology of the resorption imprints were different depending on the type of material. These changes in the surface structure created by osteoclasts are likely to affect the way osteoblasts interact with the materials and how bone is subsequently formed.     

Transport of glucose and leucine by intestinal membrane vesicles in genetic diabetes

Na+-dependent D-glucose and L-leucine uptakes by isolated small intestinal brush-border membrane vesicles were studied in normal and genetically diabetic mice (C57BL/KsJ-dbm). Vesicles from normal mice demonstrated transport characteristics and morphological appearances identical to those from other mammalian small intestinal brush-border membrane isolates. There was no difference found between genetically diabetic mice and their littermate controls. These data suggest that the small intestinal brush-border membrane transport is not altered in genetic diabetes in contrast to that found in drug-induced diabetes.     

Efficient scheduling policies to reduce mean and variance ofcycle-time in semiconductor manufacturing plants

The problem of reducing the mean and variance of cycle time in semiconductor manufacturing plants is addressed. Such plants feature a characteristic reentrant process flow, where lots repeatedly return at different stages of their production to the same service stations for further processing, consequently creating much competition for machines. We introduce a new class of scheduling policies, called Fluctuation Smoothing policies. Unanimously, our policies achieved the best mean cycle time and Standard Deviation of Cycle Time, in all the configurations of plant models and release policies tested. As an example, under the recommended Workload Regulation Release policy, for a heavily loaded Research and Development Fabrication Line model, our Fluctuation Smoothing policies achieved a reduction of 22.4% in the Mean Queueing Time, and a reduction of 52.0% in the Standard Deviation of Cycle Time, over the baseline FIFO policy. These conclusions are based on extensive simulations conducted on two models of semiconductor manufacturing plants. The first is a model of a Research and Development Fabrication Line. The second is an aggregate model intended to approximate a full scale production line. Statistical tests are used to corroborate our conclusions     

The recovery of vanadium from dilute acid sulfate solutions by resin ion exchange

A detailed study has been carried out to investigate the possibility of recovering vanadium by resin ion exchange from acid sulfate solutions containing 10 mg/l vanadium. In particular the recovery of vanadium by an anion exchange resin, Dowex 21K, has been investigated. Batch loading tests have been carried out to elucidate the role of E_h and pH on vanadium loading. An E_h-pH diagram has been constructed to determine the most stable vanadium species in solution at different E_h and pH conditions, and this information has been used to explain and predict the loading of vanadium onto the anion exchange resin. Kinetic data have been obtained for the loading of vanadium at different pH values. A film diffusion model has been found to fit the experimental data gathered at pH 4.0, while a particle diffusion model seems to offer a better fit to the experimental data at pH 2.0.     

High pressure gelation of soy proteins: Effect of concentration, pH and additives

The global demand for soybean protein has increased dramatically over the last few years due to its versatility. High pressure (HP) processing is emerging as an effective alternative to thermal processing of foods. The HP treatment of protein solutions at different process conditions can cause partial unfolding of proteins that can lead to the irreversible gelation of the product. In this study, the influence of protein concentration (5–20% w/v), pH (3–7), sugar (5% w/v), CaCl₂ (5% w/v), pressure level (up to 650 MPa) and holding time (0.1 and 10 min), and process temperature (20 and 40 °C) on the dynamic rheology of soybean protein concentrate (SPC) solutions was evaluated. Furthermore, the protein structural changes caused by HP were studied, through the use of the extrinsic fluorescence of the probe 8-anilino-1-naphthalene sulfonic acid (ANS) and Fourier transform infrared (FTIR) spectroscopy. Results indicated a strong influence of protein concentration on both elastic (G′) and viscous (G″) moduli, increasing with concentration. Increase in pressure and holding time produced an increase on both G′ and G″ for SPC concentrations higher than 10%; at 15% SPC concentration, a relatively low pressure treatment of 250 MPa achieved the cross-over of G′ over G″. The structure of the soybean proteins suffered limited changes after HP treatment; hydrophobicity increased, as well as the relative proportion of random coil, while the β-sheet content decreased. HP treatment can be used to enhance the viscoelastic behavior of SPC after which SPC can be used to enrich both protein content and textural properties of foods.