Size considerations in interfacing thermoacoustic coolers with electronics

Journal ArticleSmall thermoacoustic coolers heat pumps show much promise for heat management in microcircuits, especially since they can be miniaturized for interfacing with circuits. Usually they are operated in the resonant mode with sound pumping heat; the device dimensions are reduced when the acoustic pump frequency is raised. Results on the development of this technology will be presented for devices operating in the frequency range of 4 kHz to 25 kHz. Since the efficiency and cooling power depend on geometric factors, scaling in the miniaturization plays an important role. The cooling power varies with the total effective cross-sectional area of stack relative to sound field and hence on the cross-sectional area at stack position

Structure of the Deformed 7075 Aircraft Al - Alloy with Material Analysis Using Diffraction (MAUD)

This work aims to study the effect of plastic deformation on the 7075 Al - alloy using Material Analyses Using Diffraction (MAUD). Plastic deformation produces dislocation defects. Using a hydraulic press, samples were deformed up to 25%. The XRD was measured for each degree of deformation. The MAUD program was used to analyze the data, and mathematical methods were deployed to understand the various behaviors observed. The lattice parameter, crystallite size, average internal stress, micro-strain, and dislocation density of the 7075Al-alloy were calculated. As the deformation degree increased, there was a progressive decline in the crystallite size as an increase in the micro-strain and dislocation density. The flow stress changes from 5.8 to 49 MPa and the stored dislocation energy varies from 2.62 to 185 kPa

Study of the Optical Properties of Zno Nano-structure at Different Ti Content

Zinc oxide (ZnO) and TZO samples having different Ti content were synthesized from doping to composite by Citrate sol-gel method (dissolving and react with citric acid) characterized according to their optical properties. The UV - vis characterization exhibiting good optical properties. The results show there are one absorption edge at pure and low Ti doping but at higher Ti% another edge appeared and slightly shifted around 400 nm. The maximum absorption nearly at 350 nm, and the band gap energy of Ti-doped ZnO increase from 3.16 to 3.20 eV achieving a blue-shift. A red shift from 3.07 to 3.19 eV in the visible range which has a very important application, this improves the optical properties of ZnO and gives an indication how to tune its band gap (increase or decrease by doping or composition)

Biochemical changes occurring during fermentation of camel milk by selected bacterial starter cultures

The biochemical changes in amino acids, water soluble vitamins, soluble sugars and organic acids occurring during fermentation (at 43°C for 6 h) of camel milk inoculated with Streptococcus thermophilus 37, Lactobacillus delbrueckii sub sp. bulgaricus CH2, Lactococcus lactis, Lactobacillus acidophilus and mixed yogurt culture (S. thermophilus and L. bulgaricus 1:1) were studied. Amino acids analysis revealed slight insignificant increase in alanine, leucine, histidine, lysine and argninie, while valine, methionine and tyrosine were slightly decreased. The fermentation process significantly decreased vitamin C contents, while it had no significant effect on riboflavin and thiamine content. Single as well as mixed culture fermentation resulted in decrease in lactose concentration with parallel increase in glucose and galactose. Organic acids analysis revealed the presence of lactic acid, formic acid and acetic acid, with yogurt culture showing the highest concentration of lactic acid, formic acid and acetic acid, while L. lactis showed lowest concentration.Key words: Camel milk, fermentation, amino acids, organic acids, vitamins, sugars

Influence of Some Innovation Attributes on the Adoption of Growing Sunflower in Rahad Scheme

The vital economic importance of sunflower as one of the oil crops encouraged its introduction to the Sudan in the last twenty years. The production of sunflower crop began in Rahad scheme, as in other irrigated areas in the country, in 1992/93 growing season. Field survey was used to collect data from 100 sunflower growers (adopters) in Rahad Scheme (block 10) in 2002/2003 growing season selected from a total population of 1000-1100 farmers by using the simple random sample technique. An equal number of non-adopters was selected for comparison. The total number of interviewed farmers was 200. The collected data was statistically analyzed using the chi-square test. The results showed significant association (dependency) between adoption of growing sunflower (the innovation) and some of its attributes: Relative advantage on perceived production cost and income, compatibility with farmers need as cash crop and animal feed, complexity associated with use of technical package for sunflower. From the findings of this study, we can conclude that the adoption of this crop was dependent on some innovation attributes and the results were expected to reveal factors influencing adoption of the crop. The authors recommend that more attention should be given by agronomists to this crop in order to improve the yield of the crop and extension services should design special programs for the crop to promote its rate of adoption

Isolation, Identification and Characterization of Salmonella spp. from Chicken purchased at Wad Madani City, Gezira State, Sudan

Background: Salmonella is a potential human pathogen that causes salmonellosis, a food-borne disease. Addressing these major food safety and public health issues with effective monitoring of food-borne pathogens and dietary measures.Methods: A cross-sectional study was conducted in the local markets of Alsug Alkabeer (AB), Alsug Ashabi (AK), and Alsug Alsageer (AS) sites in Wad Madani state, Sudan to detect and assess Salmonella infection in raw and cooked chicken samples.Results: The results showed that the maximum number of different Salmonella species was recovered from raw and cooked specimens of chicken obtained from AB, AK and AS which were 6.5, 4.4, and 4cfu/g, respectively. In addition, Salmonella spp. in the locally reared chicken is significantly (p < 0.05) higher than that of farm poultry. On the other hand, the highest Salmonella count was recorded in AS, AK and AB egg samples which were 5.9, 3.5, and 2.3cfu/g, respectively. Interestingly, eggs from local sources of chicken had significantly (p < 0.05) higher numbers of Salmonella spp. compared to those from farm sources. Six species of Salmonella were described, namely: Salmonella typhi, S. cheers, S. arizonae, S. enteritidis, S. pullorum, and S. gallinarum.Conclusion: High occurrence of Salmonella spp. in this study might be attributed to the low hygienic measures in the poultry retail markets during slaughtering and/or handling processes. Further studies are required and should be conducted within Gezira state to assess food safety.Keywords: Food-borne disease; Pathogens; Biochemical test; Contamination; Food safety; Microbial growth; Food poisonin

Management of TB in the private sector in Khartoum, Sudan: quality and impact on TB control

IntroductionSudan has a large and growing private health sector. No survey was done in Sudan to show the extent of the use of private health care services by the population. Also precise data on tuberculosis (TB) diagnosis and treatment in the private sector are not available.Material and methodsA facility-based cross-sectional survey was carried out during February2007-June 2007 in Khartoum state, whereby consented private physicians working in the all private clinics (n=110) were interviewed.ResultsThis study showed that a large private sector exist in the country and deliver care to TB patients and reported the non-adherence of this sector to National Tuberculosis Program (NTP) guidelines. 59.1% of the interviewed physicians correctly mentioned the TB treatment regimens, only 8(12.3%) physicians that reported management of TB patients actually prescribed these regimens to their patients. Similarly, only 10(15.4%) physicians requested sputum smear examination for TBdiagnosis.ConclusionA considerable proportion of cases is inadequately managed by the private sector and is not notified to NTP. The information delivered by this study can be used to develop a workable Public-private mix (PPM) model with the private sector.Key words: Isoniazid, Rifampicin, Pyrazinamide, Ethambutol

Improvements to deep convolutional neural networks for LVCSR

Deep Convolutional Neural Networks (CNNs) are more powerful than Deep Neural Networks (DNN), as they are able to better reduce spectral variation in the input signal. This has also been confirmed experimentally, with CNNs showing improvements in word error rate (WER) between 4-12% relative compared to DNNs across a variety of LVCSR tasks. In this paper, we describe different methods to further improve CNN performance. First, we conduct a deep analysis comparing limited weight sharing and full weight sharing with state-of-the-art features. Second, we apply various pooling strategies that have shown improvements in computer vision to an LVCSR speech task. Third, we introduce a method to effectively incorporate speaker adaptation, namely fMLLR, into log-mel features. Fourth, we introduce an effective strategy to use dropout during Hessian-free sequence training. We find that with these improvements, particularly with fMLLR and dropout, we are able to achieve an additional 2-3% relative improvement in WER on a 50-hour Broadcast News task over our previous best CNN baseline. On a larger 400-hour BN task, we find an additional 4-5% relative improvement over our previous best CNN baseline.Comment: 6 pages, 1 figur

DESIGN AND EVALUATION OF DOMPERIDONE SUBLINGUAL TABLETS

Objective: The aim of this work was to enhance the bioavailability of poorly soluble, anti-emetic drug; domperidone (DMP) having a poor oral bioavailability (13-17%) due to extensive first pass metabolism. The goal of this study was achieved through solubilization of DMP using solid dispersion technology followed by incorporation of solid dispersions into sublingual tablets to bypass pre-systemic metabolism.Methods: Solid dispersions of DMP with Pluronic F-68 were prepared in different weight ratios by fusion method and they were evaluated for their in vitro dissolution rate to select the best ratio for final formulation. Then, solid dispersions were formulated into sublingual tablets in combination with various soluble excipients. Sublingual tablets were prepared by direct compression technique and evaluated for their physical properties, in vitro dissolution rate and kinetics of drug release. The best formulae were selected for in vivo studies in rabbits in comparison with marketed oral tablets; Motinorm®.Results: Solid dispersions of DMP with Pluronic F-68 in a weight ratio of 1:7 (w/w) showed the highest dissolution rate and were selected for sublingual tablets formulation. Sublingual tablets formulae S16 (containing Fructose and 10% w/w Ac-Di-Sol) and S20 (containing Fructose and 10% w/w Explotab) showed the best results and were selected for in vivo studies in rabbits. The selected formulae showed marked enhancement of DMP bioavailability compared with the commercial oral tablets; Motinorm®, with relative bioavailability values of 432.49±10.13% and 409.32±11.59 % for S16 and S20, respectively.Conclusion: The results confirmed that sublingual tablets were an effective tool for DMP delivery with marked enhancement of bioavailability.Keywords: Domperidone, Solubility, Solid dispersions, Sublingual tablets, First-pass metabolism, Bioavailabilit