98 research outputs found

    A Review of Materials used for Solid Oxide Fuel Cell

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    Abstract: To have the benefits of clean electric power with out engines, solar panels and wind farms which are familiar sources of alternative energy were a dream of the engineers and environmentalists. Even though they are effective sources of electric energy, there are problems with the stability of their energy sources at all times. Extracting electricity from a device called as "solid electrolyte fuel cell" were demonstrated by the scientists and since then there has been an intense research and development effort on alternative energy technology known as fuel cells. Now, as energy issues are at the forefront of current events, fuel cell technology is ripening and on the verge of being ready for large scale commercial implementation. This paper briefly reviews materials currently used in the solid oxide fuel cells ,merits and demerits of the various materials used in SOFC such as Electrolytes, Anode, Cathode and Interconnects are discussed and in addition various fabrication processes and structural supports are reviewed. Materials are to be developed for all components of SOFC, in order to reduce operating temperature and overall cost

    The impact of Bt cotton on poor households in rural India

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    The impact of genetically modified (GM) crops on the poor in developing countries is still the subject of controversy. While previous studies have examined direct productivity effects of Bacillus thuringiensis (Bt) cotton and other GM crops, little is known about wider socioeconomic outcomes. We use a microeconomic modelling approach and comprehensive survey data from India to analyse welfare and distribution effects in a typical village economy. Bt cotton adoption increases returns to labour, especially for hired female workers. Likewise, aggregate household incomes rise, including for poor and vulnerable farmers. Hence, Bt cotton contributes to poverty reduction and rural development

    The effect of prior walking on coronary heart disease risk markers in South Asian and European men.

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    Purpose: Heart disease risk is elevated in South Asians possibly due to impaired postprandial metabolism. Running has been shown to induce greater reductions in postprandial lipaemia in South Asian than European men but the effect of walking in South Asians is unknown. Methods: Fifteen South Asian and 14 White European men aged 19-30 years completed two, 2-d trials in a randomised crossover design. On day 1, participants rested (control) or walked for 60 min at approximately 50% maximum oxygen uptake (exercise). On day 2, participants rested and consumed two high fat meals over a 9h period during which 14 venous blood samples were collected. Results: South Asians exhibited higher postprandial triacylglycerol (geometric mean (95% confidence interval) 2.29(1.82 to 2.89) vs. 1.54(1.21 to 1.96) mmol·L-1·hr-1), glucose (5.49(5.21 to 5.79) vs. 5.05(4.78 to 5.33) mmol·L-1·hr-1), insulin (32.9(25.7 to 42.1) vs. 18.3(14.2 to 23.7) µU·mL-1·hr-1) and interleukin-6 (2.44(1.61 to 3.67) vs. 1.04(0.68 to 1.59) pg·mL-1·hr-1) than Europeans (all ES ≥ 0.72, P≤0.03). Between-group differences in triacylglycerol, glucose and insulin were not significant after controlling for age and percentage body fat. Walking reduced postprandial triacylglycerol (1.79(1.52 to 2.12) vs. 1.97(1.67 to 2.33) mmol·L-1·hr-1) and insulin (21.0(17.0 to 26.0) vs. 28.7(23.2 to 35.4) µU·mL-1·hr-1) (all ES ≥ 0.23. P≤0.01), but group differences were not significant. Conclusions: Healthy South Asians exhibited impaired postprandial metabolism compared with White Europeans, but these differences were diminished after controlling for potential confounders. The small-moderate reduction in postprandial triacylglycerol and insulin after brisk walking was not different between the ethnicities

    Multi-location evaluation of pigeonpea (Cajanus cajan) for broad-based resistance to sterility-mosaic disease in India

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    A total of 141 germplasm accessions and 725 breeding lines of pigeon pea were evaluated for resistance to pigeon pea sterility mosaic virus at 13 field locations in India from 1983-84 to 1989-90. Some 50 seeds per test entry were sown at each location and the trials were artificially inoculated by either leaf-stapling (in which 10-15-day-old seedlings were stapled with diseased leaves harbouring mites) or the infector-hedge method (with the susceptible variety NP(WR)15 sown on the border of the nursery 4-6 months in advance of the normal sowing date). The breeding lines included in the evaluation were newly bred, high-yielding lines entered into the Pigeon Pea Co-ordinated trials by ICRISAT and the All-India Co-ordinated Pulses Improvement Project. ICP7182 was used as the susceptible control line. Information is presented on lines and accessions showing broad-based resistance (percentage infection at maturity) during the trial period at each location. Line ICP7035 from Madhyha Pradesh, which contains DSLR55 in its pedigree, was resistant at 12 locations and some 18 lines were resistant at 10 locations

    Multilocational Evaluation of Pigeonpea for Broad-Based Resistance to Fusarium Wilt in India

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    Nine-hundred and fifty-nine plgeonpea germplasm and breeding lines were evaluated for resistance to wilt caused by Fusarium udum Butler at 12 locations in India over a period of 7 years between 1984 and 1990. ICP 8863,9174,12745, ICPL333,8363,88047, BWR 370, DPPA 85-2,85-3,85-8,85–13,85–14 and Bandapalera were resistant or moderately resistant at 7 to 10 out of 12 locations for 3 to 5 years with an average wilt incidence of less than 15%

    From computational discovery to experimental characterization of a high hole mobility organic crystal

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    For organic semiconductors to find ubiquitous electronics applications, the development of new materials with high mobility and air stability is critical. Despite the versatility of carbon, exploratory chemical synthesis in the vast chemical space can be hindered by synthetic and characterization difficulties. Here we show that in silico screening of novel derivatives of the dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene semiconductor with high hole mobility and air stability can lead to the discovery of a new high-performance semiconductor. On the basis of estimates from the Marcus theory of charge transfer rates, we identified a novel compound expected to demonstrate a theoretic twofold improvement in mobility over the parent molecule. Synthetic and electrical characterization of the compound is reported with single-crystal field-effect transistors, showing a remarkable saturation and linear mobility of 12.3 and 16 cm2 V−1 s−1, respectively. This is one of the very few organic semiconductors with mobility greater than 10 cm2 V−1 s−1 reported to date

    Noise Contributions in an Inducible Genetic Switch: A Whole-Cell Simulation Study

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    Stochastic expression of genes produces heterogeneity in clonal populations of bacteria under identical conditions. We analyze and compare the behavior of the inducible lac genetic switch using well-stirred and spatially resolved simulations for Escherichia coli cells modeled under fast and slow-growth conditions. Our new kinetic model describing the switching of the lac operon from one phenotype to the other incorporates parameters obtained from recently published in vivo single-molecule fluorescence experiments along with in vitro rate constants. For the well-stirred system, investigation of the intrinsic noise in the circuit as a function of the inducer concentration and in the presence/absence of the feedback mechanism reveals that the noise peaks near the switching threshold. Applying maximum likelihood estimation, we show that the analytic two-state model of gene expression can be used to extract stochastic rates from the simulation data. The simulations also provide mRNA–protein probability landscapes, which demonstrate that switching is the result of crossing both mRNA and protein thresholds. Using cryoelectron tomography of an E. coli cell and data from proteomics studies, we construct spatial in vivo models of cells and quantify the noise contributions and effects on repressor rebinding due to cell structure and crowding in the cytoplasm. Compared to systems without spatial heterogeneity, the model for the fast-growth cells predicts a slight decrease in the overall noise and an increase in the repressors rebinding rate due to anomalous subdiffusion. The tomograms for E. coli grown under slow-growth conditions identify the positions of the ribosomes and the condensed nucleoid. The smaller slow-growth cells have increased mRNA localization and a larger internal inducer concentration, leading to a significant decrease in the lifetime of the repressor–operator complex and an increase in the frequency of transcriptional bursts

    Frequency and antimicrobial resistance patterns of bacteria implicated in community urinary tract infections: a ten-year surveillance study (2000-2009)

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    BACKGROUND Urinary tract infection (UTI) is one of the most common infectious diseases at the community level. In order to assess the adequacy of the empirical therapy, the prevalence and the resistance pattern of the main bacteria responsible for UTI in the community (in Aveiro, Portugal) was evaluated throughout a ten-year period. METHODS In this retrospective study, all urine samples from patients of the District of Aveiro, in ambulatory regime, collected at the Clinical Analysis Laboratory Avelab during the period 2000-2009 were analysed. Samples with more than 105 CFU/mL bacteria were considered positive and, for these samples, the bacteria were identified and the profile of antibiotic susceptibility was characterized. RESULTS From the 155597 samples analysed, 18797 (12.1%) were positive for bacterial infection. UTI was more frequent in women (78.5%) and its incidence varied with age, affecting more the elderly patients (38.6%). Although E. coli was, as usual, the most common pathogen implicated in UTI, it were observed differences related to the other bacteria more implicated in UTI relatively to previous studies. The bacteria implicated in the UTI varied with the sex of the patient, being P. aeruginosa a more important cause of infection in men than in women. The incidence of the main bacteria changed over the study period (P. aeruginosa, Klebsiella spp and Providencia spp increased and Enterobacter spp decreased). Although E. coli was responsible for more than an half of UTI, its resistance to antibiotics was low when compared with other pathogens implicated in UTI, showing also the lowest percentage of multidrug resistant (MDR) isolates (17%). Bacteria isolated from females were less resistant than those isolated from males and this difference increased with the patient age. CONCLUSIONS The differences in sex and age must be taken into account at the moment of empirical prescription of antimicrobials. From the recommended antimicrobials by the European Association of Urology guidelines, the first line drugs (pivmecillinam and nitrofurantoin) and the alternative antibiotic amoxicillin-clavulanic acid (AMX-CLA) are appropriate to treat community-acquired UTI, but the fluoroquinolones should not be suitable to treat male infections and the trimethoprim-sulfamethoxazole (SXT) shall not be used in the treatment of UTI at this level.Thanks are due to the University of Aveiro, Centre for Environmental and Marine Studies (CESAM) for funding the Microbiology Research Group (Project Pest-C/MAR/LA0017/2011) and to Clinical Analysis Laboratory Avelab (Portugal) for supplying the data.publishe

    Experimental Investigation on the Effectiveness of Solar Still and Its Effect on Adsorption with Various Dyes

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    The typical solar still with internal and exterior heat transfer was used to test the impact of mixing various colours into the basin water. This is well-known that enhancing distillation involves adding black dye to basin water. Identical design parameters create two single-slope basin-type solar stills (effective area 0.5 m2). This study conducted experiments to add black, green, blue, and red dyes to basin water during the winter for 24 hours. For more than a month, the amount of distilled water recovered per hour, with varying temperatures and solar activity (May 2021). This research aims to (i) examine the effect of various dyes with basin water on the internal and external heat transfer and performance of the system and (ii) study the effect of adding dyes into the basin water on increasing energy balance by the solar system. This is indicated by the fact that the introduction of colours into the basin water has a major impact on external and interior heat transfer. The evaporation, radiation, and heat transfer rate from liquid to glass significantly impact how well the filtration system works
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