Process parameters for hydrocooling apricots, plums, and peaches

Freshly harvested apricots, plums, and peaches in crates containing 5–20kg were hydrocooled in flowing water at 1°C and 50mms^-1. The cooling parameters: lag factor, cooling coefficient, and time to half-cool, determined from the exponential decline in the dimensionless ratio of temperature differences between fruit centre and coolant temperature at time t and at zero time, varied somewhat with crate load. Increasing the load from 5 to 20kg increased the time to half-cool apricots by 17% and plums and peaches by 39%.     

Microstructural changes associated with the laser processing of Al-SiC composites

On leave from: Scientific Research Council.Present address: PO Box, 9225, Baghdad, Iraq.     

IgG2 associated hypergammaglobulinaemia in some Nigerians with HIV infection

Concentrations of immunoglobulins (IgA, IgG and IgM) were measured in Nigerians with (HIV) infection. Considerable elevations up to two-fold the reference values were observed for IgG and IgM in the patient group as a whole but elevations in IgA concentration were least marked albeit significantly different from the healthy subjects. Elevation of a particular isotype was not always concomitant with elevation of the other major classes in the same patient. Overall, these elevations were observed in both symptomatic and asymptomatic infected subjects. Further analysis of IgG hyperglobulinemia showed that increases in this major class may be due to increased IgG2 subclass concentrations. It is suggested that elevation of IgG2 subclass in Nigerians with HIV infection and not IgG1 or IgG3 may be due to genetic and environmental factors rather than variation in the strain of the virus.     

Acquisition and reversal of taste/tactile discrimination after forebrain noradrenaline depletion.

Assessed the role of noradrenaline (NA) on the acquisition of an aversively motivated discrimination task and its reversal. A conditioned taste aversion procedure was used. NA depletions were achieved through 2 pharmacological means: systemic N-2 chloroethyl-N-ethyl-2-bromo-benzylamine (DSP4) and destruction of the dorsal noradrenergic bundle (DNAB) with 6-hydroxydopamine (6-OHDA). Both procedures caused marked reductions of NA in the frontal cortex and hippocampus. In neither of the studies (Exp 1, DSP4 and Exp 2, DNAB) were there any significant changes between controls and NA-depleted rats in either the rate of acquisition of the original discrimination (Phase 1) or the subsequent reversal (Phase 2). This occurred irrespective of which of the 2 stimuli (a taste cue or a tongue-tactile cue) initially was used as the conditioned stimulus/stimuli (CS) (the stimulus first followed by contingent administration of lithium chloride and later, by saline injections). Thus NA does not appear to be critically involved in the acquisition and reversal of a taste/tactile discrimination task. The significance of forebrain NA for other discrimination tasks is discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

DC offsets in direct conversion multistandard wireless receivers: Modeling and cancellation

To realize a high performance direct conversion receiver for multistandard wireless communications, the limiting factors in the direct conversion receiver should be identified and removed. In this paper, among many problems in direct conversion receivers, the DC offset problem is studied. The origins of the DC offset are summarized, and three self-mixing mechanisms generating the DC offset are modeled to better understand how the static (or time-invariant) and dynamic (or time-varying) DC offsets are produced from the mechanisms. A DC offset cancellation scheme consisting of a static DC offset canceller and a dynamic DC offset canceller is proposed and verified through simulations. Seok-Bae Park received the B.S. and M.S. degrees in Electrical Engineering from Seoul National University, Seoul, Korea, and the M.S. and Ph.D. degrees in Electrical and Computer Engineering from Ohio State University, Columbus, Ohio. He is currently with Firstpass Technologies, Inc., Dublin, Ohio as a Senior RF and Mixed-Signal Design Engineer. His current interests include low voltage/low power CMOS RF/analog/mixed-signal integrated circuits and systems for wireless communications. Mohammed Ismail has over 20 years experience of R&D in the fields of analog, RF and mixed signal integrated circuits. He has held several positions in both industry and academia and has served as a corporate consultant to nearly 30 companies in the US, Europe and the far east. He is Professor and The Founding Director of the Analog VLSI Lab, The Ohio State University. He advised the work of 40 PhD students and of 85 MS students. His current interest lies in research involving digitally programmable/configurable fully integrated radios with focus on low voltage/low power first-pass solutions for 3G and 4G wireless handhelds. He publishes intensively in this area and has been awarded 11 patents. He has coedited and coauthored several books including a text on Analog VLSI Signal and Information Processing, McGraw Hill. His last book (2004) is entitled CMOS PLLs and VCOs for 4G Wireless, Springer. He co-founded ANACAD-Egypt (now part of Mentor Graphics, Inc.) and Firstpass Technologies Inc., a developer of CMOS radio and mixed signal IPs for handheld wireless applications. Dr. Ismail has been the recipient of several awards including the US National Science Foundation Presidential Young Investigator Award, the US Semiconductor Research Corp Inventor Recognition Awards in 1992 and 1993, and a Fulbright/Nokia fellowship Award in 1995. He is the founder of the International Journal of Analog Integrated Circuits and Signal Processing, Springer and serves as the Journal’s Editor-In-Chief. He has served as Associate Editor for many IEEE Transactions, was on the Board of Governors of the IEEE Circuits and Systems Society and is the Founding Editor of “The Chip” a Column in The IEEE Circuits and Devices Magazine. He obtained his BS and MS degrees in Electronics and Communications from Cairo University, Egypt and the PhD degree in Electrical Engineering from the University of Manitoba, Canada. He is a Fellow of IEEE.     

Association between plasma vitamin E concentration and the risk of equine motor neuron disease

Venous ulceration is a common problem in western countries and results in large costs to healthcare systems. A number of hypotheses of the mechanisms of development of venous ulceration have been advanced, but this question has not been fully resolved. In recent years research effort has focused on the microcirculation of the skin and many methods of investigation have been employed to study this. Some of the principal findings described in published work are reviewed in this article. It seems unlikely from the available evidence that venous ulceration is attributable solely to failure of diffusion of oxygen and other small nutritional molecules to the tissues of the skin. The microvascular changes in the skin are characterised by activated endothelium and perivascular inflammatory cells. It is much more likely that leucocytes attach themselves to the cutaneous microcirculation, become activated and produce endothelial injury. Repeated over many months or years, this chronic inflammatory process leads to be tissues changes of lipodermatosclerosis. Although there is evidence of leucocyte involvement in the pathogenesis of venous ulceration, the exact mechanisms remain to be resolved. Improved treatment for patients may be devised once a better understanding of the basic causes of this condition has been reached.     

A Highly Linear CMOS Baseband Chain for Wideband Wireless Applications

The emergence of wide channel bandwidth wireless standards requires the use of a highly linear, wideband integrated CMOS baseband chain with moderate power consumption. In this paper, we present the design of highly linear, wideband active RC filters and a digitally programmable variable gain amplifier. To achieve a high unity gain bandwidth product with moderate power consumption, the feed‐forward compensation technique is applied for the design of wideband active RC filters. Measured results from a 0.5 µm CMOS prototype baseband chain show a cutoff frequency of 10 MHz, a variable gain range of 33 dB, an in‐band IIP3 of 13 dBV, and an input referred noise of 114 µVrms while dissipating 20 mW from a 3 V supply.     

Application of nonlinear finite strip technique to concrete deep beams

The salient features of an alternative version of the nonlinear finite strip method for analysing reinforced concrete elements is presented. Unlike the conventional finite strip models which can only handle structures whose geometry does not change in one direction, the newly developed finite strip model can analyse certain structures whose geometry (although still fairly simple) can change along their length such as deep beams with local changes of crosssection along their span(s). Moreover, unlike the conventional finite strip models, the new alternative model has the desirable feature of being able to incorporate any desired boundary conditions and different number of harmonics in various strips with minimal effort. Although the proposed model may, in certain cases, suffer when compared with the conventional alternatives, from the potential drawback of an increased number of strips with associated increases in computer storage, the present model needs many less displacement parameters at each nodal line because of the often substantially shorter lengths of the finite strips (cf. conventional strips) and, hence, needs a much narrower half-bandwidth (HBW) in the stiffness matrix with obvious savings in the subsequent computer running time. Very encouraging correlations have been found between predictions based on the present model and some recently reported test data on deep beams: these include continuous RC deep beams with changes of cross-sections over the supports and also simply supported RC deep beams covering a wide range of design parameters. In addition, the present method has been used to analyse data from a series of tests on RC deep beams with fixed-fixed boundary conditions. The numerical results for deep beams with fixed-fixed boundary conditions based on the present model provide a desirable double check on the validity of a recently reported, largely hand-based, method and should be valuable in identifying the areas in which further work may be required.     

Evaluation of empirically derived PVT properties for Pakistani crude oils

This study evaluates the most frequently used pressure-volume-temperature (PVT) empirical correlations for Pakistani crude oil samples. The evaluation is performed by using an unpublished data set of 22 bottomhole fluid samples collected from different locations in Pakistan. Based on statistical error analysis, suitable correlations for field applications are recommended for estimating bubblepoint pressure, oil formation volume factor (FVF), oil compressibility and oil viscosity.     

Predicting the Bubble-Point Pressure and Formation-Volume-Factor of Worldwide Crude Oil Systems

This paper presents models for predicting the bubble-point pressure (P_b) and oil formation-volume-factor at bubble-point (B_ob) for crude oil samples collected from several regions around the world. The regions include major producing oil fields in North and South America, North Sea, South East Asia, Middle East, and Africa. The model was developed using artificial neural networks with 5200 experimentally obtained PVT data sets. This represents the largest data set ever collected to be used in developing P_b and B_ob models. An additional 234 PVT data sets were used to investigate the effectiveness of the neural network models to predict outputs from inputs that were not used during the training process. The network model is able to predict the bubble-point pressure and the oil formation-volume-factor as a function of the solution gas-oil ratio, the gas relative density, the oil specific gravity, and the reservoir temperature. In order to obtain a generalized accurate model, back propagation with momentum for error minimization was used. The accuracy of the models developed in this study was compared in details with several published correlations. This study shows that if artificial neural networks are successfully trained, they can be excellent reliable predictive tools to estimate crude oil properties better than available correlations. The network models can be easily incorporated into any reservoir simulators and/or production optimization software.