Natural convection flow of a non-Newtonian fluid between two concentric vertical cylinders

Summary The natural convection of a homogeneous incompressible fluid of grade three between two infinite concentric vertical cylinders is studied. We consider the effect of the non-Newtonian nature of the fluid on the skin friction and heat transfer. Some numerical experimentation is presented to show the effect on the velocity and temperature profiles as the dimensionless parameters are varied.     

A comparison of silver ion HPLC plus GC with Fourier-transform IR spectroscopy for the determination of trans double bonds in unsaturated fatty acids

A rapid procedure has been developed for the isolation of methyl esters of trans-monoenoic fatty acids by silver ion high-performance liquid chromatography. The combined saturated plus trans-monoene fraction was collected for analysis by gas chromatography and comparison with the composition of the unfractionated sample. The trans-monoene contents of partially hydrogenated vegetable oils, determined in this way, are compared with data obtained by Fourier-transform infrared spectroscopy. Alternative methods of base-line correction are discussed. The infrared technique gave values that were a little higher than the chromatographic ones, presumably because the former also detected trans unsaturation in di- and polyunsaturated fatty acids.     

Intra-renal and subcellular distribution of the human chloride channel, CLC-5, reveals a pathophysiological basis for Dent's disease

Dent's disease, which is a renal tubular disorder characterized by low molecular weight proteinuria, hypercalciuria and nephrolithiasis, is associated with inactivating mutations of the X-linked chloride channel, CLC-5. However, the manner in which a functional loss of CLC-5 leads to such diverse renal abnormalities remains to be defined. In order to elucidate this, we performed studies to determine the segmental expression of CLC-5 in the human kidney and to define its intracellular distribution. We raised and characterized antisera against human CLC-5, and identified by immunoblotting an 83 kDa band corresponding to CLC-5 in human kidney cortex and medulla. Immunohistochemistry revealed CLC-5 expression in the epithelial cells lining the proximal tubules and the thick ascending limbs of Henle's loop, and in intercalated cells of the collecting ducts. Studies of subcellular human kidney fractions established that CLC-5 distribution was associated best with that of Rab4, which is a marker of recycling early endosomes. In addition, confocal microscopy studies using the proximal tubular cell model of opossum kidney cells, which endogenously expressed CLC-5, revealed that CLC-5 co-localized with the albumin-containing endocytic vesicles that form part of the receptor-mediated endocytic pathway. Thus, CLC-5 is expressed at multiple sites in the human nephron and is likely to have a role in the receptor-mediated endocytic pathway. Furthermore, the functional loss of CLC-5 in the proximal tubules and the thick ascending limbs provides an explanation for the occurrences of low molecular weight proteinuria and hypercalciuria, respectively. These results help to elucidate further the patho-physiological basis of the renal tubular defects of Dent's disease.     

Effect of fatty acid positional distribution and triacylglycerol composition on lipid by-products formation during heat treatment: I. Polymer formation

Effects of the fatty acid positional distribution and of the triacylglycerol (TG) composition on polymerization of TG during heat treatment were studied. Diacid TG molecules, acylated only with linoleic acid or linolenic acid along with palmitic acid, and positioned either in the central position (PLP and PLnP, respectively) or in one of the two outer positions (PPL and PPLn, respectively) were synthesized. Monoacid TG, i.e., trilinolein and trilinolenin, were also synthesized and mixed with tripalmitin in a 1:2 ratio. These model TG were also compared to TG models that consisted of a canola oil and its randomized counterpart, whose fatty acid positional distribution and TG composition were determined by means of high-performance liquid chromatography (HPLC). After heating, the polymer content and composition were evaluated by HPLC-size exclusion chromatography. Both pure TG and the canola oil models showed that acylation of polyunsaturated acids in the central position was protective against polymerization, although the effect was mainly observed with linolenic acid. The synthetic-TG study showed that the monoacid TG species exhibited higher sensitivity toward polymerization than the diacid species. The slight differences in the TG species between both canola oils did not allow observation of such a relationship with regard to TG composition.     

The inkjet printing process for Lyocell and cotton fibres. Part 1: The significance of pre-treatment chemicals and their relationship with colour strength, absorbed dye fixation and ink penetration

A statistical study of the outcome of inkjet printing, using a reactive dye based ink, on three cellulosic fabrics, namley Lyocell (standard Tencel and Tencel A100) and cotton, pre-treated with urea, migration inhibitor, penetration agent and alkali is reported. Colour strength (as Integ value), absorbed dye fixation and ink penetration were analysed as main responses. A full factorial design method was applied to study the effect of the level of each ingredient in the pre-treatment formulation on the responses, together with the steaming time used for dye fixation. The interactions between variables were also evaluated. The statistically significant variables were determined for each response and contour plots constructed for the most significant interactions to assess where the optimum responses might be achieved.     

Semiconductor capacity planning: stochastic modelingand computational studies

This paper presents a multistage stochastic programming model for strategic capacity planning at a major US semiconductor manufacturer. Main sources of uncertainty in this multi-year planning problem include demand of different technologies and capacity estimations for each fabrication (fab) facility. We test the model using real-world scenarios requiring the determination of capacity planning for 29 technology categories among five fab facilities. The objective of the model is to minimize the gaps between product demands and the capacity allocated to the technology specified by each product. We consider two different scenario-analysis constructs: first, an independent scenario structure where we assume no prior information and the model systematically enumerates possible states in each period. The states from one period to another are independent from each other. Second, we consider an arbitrary scenario construct, which allows the planner to sample/evaluate arbitrary multi-period scenarios that captures the dependency between periods. In both cases, a scenario is defined as a multi-period path from the root to a leaf in the scenario tree. We conduct intensive computational experiments on these models using real data supplied by the semiconductor manufacturer. The purpose of our experiments is two-fold: first to examine different degree of scenario aggregation and its effects on the independent model to achieve high-quality solution. Using this as a benchmark, we then compare the results from the arbitrary model and illustrate the different uses of the two scenario constructs. We show that the independent model allows a varying degree of scenario aggregation without significant prior information, while the arbitrary model allows planners to play out specific scenarios given prior information.     

Theoretical and experimental analysis of wire segment holograms forstatistical interconnect metrology

Theoretical and experimental results using computer generated wire segment holograms for statistical interconnect metrology are presented. Test structures have been constructed using a process capable of imaging 1-μm features and consist of arrays of wire segments illuminated by a He-Ne Laser. Since the holograms are fabricated at the same time as actual wires on the wafer, the quality of the projected image correlates with the emergence of global feature patterning errors. Specifically, this paper presents data on the effect of varied exposure time on the intensity of the projected image. An initial statistical analysis indicates that the test structures are capable of detecting variations in wire geometry which are approximately 1.0% of the nominal wire width. It is anticipated that significant improvements to this level of sensitivity can be obtained by optimization of the holographic encoding process and test image selection     

Validity of screening for individuals at risk for type I diabetes by combined analysis of antibodies to recombinant proteins

OBJECTIVE: To determine whether screening for the presence of multiple antibody markers for IDDM is effective at identifying individuals with high risk for disease development. RESEARCH DESIGN AND METHODS: Antibodies to GAD and the tyrosine phosphatase-like protein 1A-2 were determined in sequential serum samples from 44 first-degree relatives of IDDM patients, identified as possessing islet cell antibody (ICA) and/or insulin autoantibody (IAA), who were followed prospectively for IDDM development, ICA, IAA, and antibodies to GAD and 1A-2 were also determined in 93 cases of new-onset nonfamilial IDDM. RESULTS: The presence of two or more antibodies in addition to ICA or IAA conferred high risk (61%) for development of IDDM within 5 years of entry into the study and identified 89% of those who have developed IDDM on current follow-up. None of the relatives positive for ICA or IAA alone, in the absence of other antibody markers, have developed IDDM. Antibodies to islet antigens could both appear and disappear in follow-up samples obtained after entry into the study. The majority (60%) of young (< 16 years), sporadic cases of IDDM had multiple antibodies to islet antigens, but this proportion was lower in older patients (37%). CONCLUSIONS: A screening strategy based on the analysis of antibodies to multiple islet antigens can predict IDDM at high sensitivity and specificity in families, and such a strategy may also be applicable to identify young individuals in the general population with high disease risk. Since appearance of antibodies to different antigens occurs sequentially rather than simultaneously, accurate assessment of diabetes risk based on the presence of multiple antibodies will require follow-up over a number of years after the first evidence of islet autoimmunity.     

Total infrared radiation property measurements of diathermanous films with a reflectometer

A procedure is described for the rapid evaluation of total infrared radiation properties of thin diathermanous films with an infrared reflectometer. Two different back reflecting surfaces are used for measurements and the resulting calculated properties are based on the assumption that the sample is gray. The transmittance value obtained by the procedure will be subject to some error, with the magnitude of the error dependent on the spectral transmittance characteristics of the sample. A statistical model spectral transmittance formula for correcting the gray result is proposed.