536 research outputs found

    Effect of Dispersions of Al2O3 on the Physical and Mechanical Properties of Pure Copper and Copper-Nickel Alloy

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    This paper illustrates the mechanical and physical properties of pure Cu and Cu-Ni (50-50 wt. %) alloy mixed with Al2O3 (1-4 wt. %) as micro-particles reinforcement materials. The attained composite alloy specimens\u27 characteristics were estimated such as microstructure, relative density, electrical and thermal conductivity, hardness, and compression yield stress properties to adjust the suitable optimum percentage of reinforcing material which has the best physical and mechanical properties with different main matrix materials whether pure Cu powder or Cu-Ni mechanical alloy. The micron-sized Al2O3 was added to enhance the mechanical and physical properties of the pure Cu and Cu-Ni alloy composites. The electrical and thermal conductivity for pure Cu alloy composites were improved compared to the copper-nickel alloy matrix composites material. The hardness and compression yield stress of pure copper has enhancement values and for Cu-Ni alloy composites have enhancement values and for Cu-Ni base composites, hardness and compression yield stress have improved with the most positive enhancement values

    The Bismut-Elworthy-Li type formulae for stochastic differential equations with jumps

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    Consider jump-type stochastic differential equations with the drift, diffusion and jump terms. Logarithmic derivatives of densities for the solution process are studied, and the Bismut-Elworthy-Li type formulae can be obtained under the uniformly elliptic condition on the coefficients of the diffusion and jump terms. Our approach is based upon the Kolmogorov backward equation by making full use of the Markovian property of the process.Comment: 29 pages, to appear in Journal of Theoretical Probabilit

    A geospatial framework to support integrated biogeochemical modelling in the United Kingdom

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    Anthropogenic impacts on the aquatic environment, especially in the context of nutrients, provide a major challenge for water resource management. The heterogeneous nature of policy relevant management units (e.g. catchments), in terms of environmental controls on nutrient source and transport, leads to the need for holistic management. However, current strategies are limited by current understanding and knowledge that is transferable between spatial scales and landscape typologies. This study presents a spatially-explicit framework to support the modelling of nutrients from land to water, encompassing environmental and spatial complexities. The framework recognises nine homogeneous landscape units, distinct in terms of sensitivity of nutrient losses to waterbodies. The functionality of the framework is demonstrated by supporting an exemplar nutrient model, applied within the Environmental Virtual Observatory pilot (EVOp) cloud cyber-infrastructure. We demonstrate scope for the use of the framework as a management decision support tool and for further development of integrated biogeochemical modelling

    The ALADIN system and its canonical model configurations AROME CY41T1 and ALARO CY40T1

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    The ALADIN System is a numerical weather prediction (NWP) system developed by the international ALADIN consortium for operational weather forecasting and research purposes. It is based on a code that is shared with the global model IFS of the ECMWF and the ARPEGE model of Meteo-France. Today, this system can be used to provide a multitude of high-resolution limited-area model (LAM) configurations. A few configurations are thoroughly validated and prepared to be used for the operational weather forecasting in the 16 partner institutes of this consortium. These configurations are called the ALADIN canonical model configurations (CMCs). There are currently three CMCs: the ALADIN baseline CMC, the AROME CMC and the ALARO CMC. Other configurations are possible for research, such as process studies and climate simulations. The purpose of this paper is (i) to define the ALADIN System in relation to the global counterparts IFS and ARPEGE, (ii) to explain the notion of the CMCs, (iii) to document their most recent versions, and (iv) to illustrate the process of the validation and the porting of these configurations to the operational forecast suites of the partner institutes of the ALADIN consortium. This paper is restricted to the forecast model only; data assimilation techniques and postprocessing techniques are part of the ALADIN System but they are not discussed here

    Renal outcome in adults with renal insufficiency and irregular asymmetric kidneys

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    BACKGROUND: The commonest cause of end-stage renal failure (ESRF) in children and young adults is congenital malformation of the kidney and urinary tract. In this retrospective review, we examine whether progression to ESRF can be predicted and whether treatment with angiotensin converting enzyme inhibitors (ACEI) can delay or prevent this. METHODS: We reviewed 78 patients with asymmetric irregular kidneys as a consequence of either primary vesico-ureteric reflux or renal dysplasia (Group 1, n = 44), or abnormal bladder function (Group 2, n = 34). Patients (median age 24 years) had an estimated GFR (eGFR) < 60 ml/min/1.73 m(2 )with at least 5 years of follow up (median 143 months). 48 patients received ACEI. We explored potential prognostic factors that affect the time to ESRF using Cox-regression analyses. RESULTS: At start, mean (SE) creatinine was 189 (8) μmol/l, mean eGFR 41 (1) ml/min 1.73 m(2), mean proteinuria 144 (14) mg/mmol creatinine (1.7 g/24 hrs). Of 78 patients, 36 (46%) developed ESRF, but none of 19 with proteinuria less than 50 mg/mmol and only two of 18 patients with eGFR above 50 ml/min did so. Renal outcome between Groups 1 and 2 appeared similar with no evidence for a difference. A benefit in favour of treatment with ACEI was observed above an eGFR of 40 ml/min (p = 0.024). CONCLUSION: The similar outcome of the two groups supports the nephrological nature of progressive renal failure in young men born with abnormal bladders. There is a watershed GFR of 40–50 ml/min at which ACEI treatment can be successful at improving renal outcome

    Physiological and cell ultrastructure disturbances in wheat seedlings generated by Chenopodium murale hairy root exudate.

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    Chenopodium murale L. is an invasive weed species significantly interfering with wheat crop. However, the complete nature of its allelopathic influence on crops is not yet fully understood. In the present study, the focus is made on establishing the relation between plant morphophysiological changes and oxidative stress, induced by allelopathic extract. Phytotoxic medium of C. murale hairy root clone R5 reduced the germination rate (24% less than control value) of wheat cv. Nataša seeds, as well as seedling growth, diminishing shoot and root length significantly, decreased total chlorophyll content, and induced abnormal root gravitropism. The R5 treatment caused cellular structural abnormalities, reflecting on the root and leaf cell shape and organization. These abnormalities mostly included the increased number of mitochondria and reorganization of the vacuolar compartment, changes in nucleus shape, and chloroplast organization and distribution. The most significant structural changes were observed in cell wall in the form of amoeboid protrusions and folds leading to its irregular shape. These structural alterations were accompanied by an oxidative stress in tissues of treated wheat seedlings, reflected as increased level of H2O2 and other ROS molecules, an increase of radical scavenging capacity and total phenolic content. Accordingly, the retardation of wheat seedling growth by C. murale allelochemicals may represent a consequence of complex activity involving both cell structure alteration and physiological processes.This is a post-peer-review, pre-copyedit version of an article published in Protoplasma. The final authenticated version is available online at: [http://dx.doi.org/10.1007/s00709-018-1250-0

    A System Dynamics Approach for Hospital Waste Management in a City in a Developing Country: The Case of Nablus, Palestine

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    Hospitals and health centers provide a variety of healthcare services and normally generate hazardous waste as well as general waste. General waste has a similar nature to that of municipal solid waste and therefore could be disposed of in municipal landfills. However, hazardous waste poses risks to public health, unless it is properly managed. The hospital waste management system encompasses many factors, i.e., number of beds, number of employees, level of service, population, birth rate, fertility rate, and not in my back yard (NIMBY) syndrome. Therefore, this management system requires a comprehensive analysis to determine the role of each factor and its influence on the whole system. In this research, a hospital waste management simulation model is presented based on the system dynamics technique to determine the interaction among these factors in the system using a software package, ithink. This model is used to estimate waste segregation as this is important in the hospital waste management system to minimize risk to public health. Real data has been obtained from a case study of the city of Nablus, Palestine to validate the model. The model exhibits wastes generated from three types of hospitals (private, charitable, and government) by considering the number of both inpatients and outpatients depending on the population of the city under study. The model also offers the facility to compare the total waste generated among these different types of hospitals and anticipate and predict the future generated waste both infectious and non-infectious and the treatment cost incurred

    India's JSY cash transfer program for maternal health: Who participates and who doesn't - a report from Ujjain district

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    <p>Abstract</p> <p>Background</p> <p>India launched a national conditional cash transfer program, Janani Suraksha Yojana (JSY), aimed at reducing maternal mortality by promoting institutional delivery in 2005. It provides a cash incentive to women who give birth in public health facilities. This paper studies the extent of program uptake, reasons for participation/non participation, factors associated with non uptake of the program, and the role played by a program volunteer, accredited social health activist (ASHA), among mothers in Ujjain district in Madhya Pradesh, India.</p> <p>Methods</p> <p>A cross-sectional study was conducted from January to May 2011 among women giving birth in 30 villages in Ujjain district. A semi-structured questionnaire was administered to 418 women who delivered in 2009. Socio-demographic and pregnancy related characteristics, role of the ASHA during delivery, receipt of the incentive, and reasons for place of delivery were collected. Multinomial regression analysis was used to identify predictors for the outcome variables; program delivery, private facility delivery, or a home delivery.</p> <p>Results</p> <p>The majority of deliveries (318/418; 76%) took place within the JSY program; 81% of all mothers below poverty line delivered in the program. Ninety percent of the women had prior knowledge of the program. Most program mothers reported receiving the cash incentive within two weeks of delivery. The ASHA's influence on the mother's decision on where to deliver appeared limited. Women who were uneducated, multiparious or lacked prior knowledge of the JSY program were significantly more likely to deliver at home.</p> <p>Conclusion</p> <p>In this study, a large proportion of women delivered under the program. Most mothers reporting timely receipt of the cash transfer. Nevertheless, there is still a subset of mothers delivering at home, who do not or cannot access emergency obstetric care under the program and remain at risk of maternal death.</p

    Surface modification of starch based blends using potassium permanganate-nitric acid system and its effect on the adherence and proliferation of osteoblastic-like cells

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    The surface modification of three starch based polymeric biomaterials, using a KMnO4/NHO3 oxidizing system, and the effect of that modification on the osteoblastic cell adhesion has been investigated. The rationale of this work is as follows—starch based polymers have been proposed for use as tissue engineering scaffolds in several publications. It is known that in biodegradable systems it is quite difficult to have both cell adhesion and proliferation. Starch based polymers have shown to perform better than poly-lactic acid based materials but there is still room for improvement. This particular work is aimed at enhancing cell adhesion and proliferation on the surface of several starch based polymer blends that are being proposed as tissue engineering scaffolds. The surface of the polymeric biomaterials was chemically modified using a KMnO4/HNO3 system. This treatment resulted in more hydrophilic surfaces, which was confirmed by contact angle measurements. The effect of the treatment on the bioactivity of the surface modified biomaterials was also studied. The bioactivity tests, performed in simulated body fluid after biomimetic coating, showed that a dense film of calcium phosphate was formed after 30 days. Finally, human osteoblast-like cells were cultured on unmodified (control) and modified materials in order to observe the effect of the presence of higher numbers of polar groups on the adhesion and proliferation of those cells. Two of the modified polymers presented changes in the adhesion behavior and a significant increase in the proliferation rate kinetics when compared to the unmodified controls.FCT (Portugal) for providing the postdoctoral grant (BPD/8491/2002)
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