270 research outputs found

    Corrosion and Grain Boundry Character Distribution(GBCD)in 316L Austenitic Stainless Steel

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    IGC (Inter-granular corrosion), in a single phase materials, is expected to depend on (a) Chemistry, (b) Grain size and (c) GBCD( Grain boundary character distr-ibution). In the present study, 316L austenitic stainless steel was deformed to different extent by unidirectional and by cross rolling. Subsequent solution: ing , i.e. a combination of primary recrystallization and grain growth, did not bring any noticeable difference in bulk texture. The GBCD, especially the 23 twin boundaries, were, however, significantly different. A difference of more than five times in low CSL (coincident site lattice) boun-daries were obtained. An effort was made to relate the effect of GBCD on corrosion - by DL- EPR (Double loop electrochemical potentiokinetic reactivation)

    A mathematical model for the development of mealiness in apples

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    Mealiness in apples (Malus domestica Borkh.) is an internal quality defect which is characterised by a dry and crumbly texture. It is related to the relative strength of the cell wall and the middle lamella. A mathematical model has been built to relate changes in the texture attributes juiciness, tensile strength and hardness, which are associated with mealiness, to the development of the turgor pressure of the tissue and the degree of hydrolysis of the middle lamella. The latter, in turn, are described in terms of properties which are meaningful from the physiological point of view, such as starch content, soluble solids content, non-hydrolysed and hydrolysed middle lamella, water in the symplast, and water in the apoplast. Biochemical reactions as well as water transfer processes are incorporated in the model. The parameter values of the model are estimated using experimental data from a storage experiment. The model fits the three texture characteristics adequately. The correlation coefficients between the parameters were below 0.96, which indicates that the model does not overfit the data

    65-micron thin monocrystalline silicon solar cell technology allowing 12-fold reduction in silicon usage

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    Thin (<70 micron) single crystal silicon solar cells have been manufactured through the use of a novel process involving selective etching. Narrow grooves are micromachined through the wafer using a standard micromachining technique with cells manufactured on the resulting silicon strips. These bifacial cells have a much greater surface area than the original wafer, leading to dramatic decreases in processing effort and silicon usage. Individual cells fabricated using the new process have displayed efficiencies up to 17.5% while a 560cm2 prototype module has displayed an efficiency of 12.3%. The size, thickness and bifacial nature of the cells offer the opportunity for a wide variety of module architectures and applications

    Television viewing through ages 2-5 years and bullying involvement in early elementary school

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    BACKGROUND: High television exposure time at young age has been described as a potential risk factor for developing behavioral problems. However, less is known about the effects of preschool television on subsequent bullying involvement. We examined the association between television viewing time through ages 2-5 and bullying involvement in the first grades of elementary school. We hypothesized that high television exposure increases the risk of bullying involvement. METHOD: TV viewing time was assessed repeatedly in early childhood using parental report. To combine these repeated assessments we used latent class analysis. Four exposure classes were identified and labeled “low”, “mid-low”, “mid-high” and “high”. Bullying involvement was assessed by teacher questionnaire (n = 3423, mean age 6.8 years). Additionally, peer/self-report of bullying involvement was obtained using a peer nomination procedure (n = 1176, mean age 7.6 years). We examined child risk of being a bully, victim or a bully-victim (compared to being uninvolved in bullying). RESULTS: High television exposure class was associated with elevated risks of bullying and victimization. Also, in both teacher- and child-reported data, children in the high television exposure class were more likely to be a bully-victim (OR = 2.11, 95% CI: 1.42-3.13 and OR = 3.68, 95% CI: 1.75-7.74 respectively). However, all univariate effect estimates attenuated and were no longer statistically significant once adjusted for maternal and child covariates. CONCLUSIONS: The association between television viewing time through ages 2-5 and bullying involvement in early elementary school is confounded by maternal and child socio-demographic characteristics

    A quality, energy and environmental assessment tool for the European cold chain

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    According to 5th Informatory Note on Refrigeration and Food published by the International Institute of Refrigeration, 20% of the global losses in perishable products was due to lack of refrigeration. It is expected that increased use of refrigeration to reduce these losses will help meet the increasing food demands of the growing world population. However, the use of refrigeration already accounts for about 15% of world’s electricity usage. In addition, the use of refrigeration significantly contributes to global warming via emission of CO2. In this paper, a software tool was developed to assess food quality and safety evolution, energy usage and CO2 emission of different refrigeration technologies along the European cold chain. A reference product was chosen for the main different food categories in the European cold chain. Software code to predict the products temperature using the room temperature as input, based on validated heat and mass transfer models, were written in Matlab (The Mathworks Inc., Natick, USA). Also, based on validated kinetic models for the different quality indicators of the reference products, a software code was written to calculate the quality and safety evolutions of the food product, using the predicted product temperature as input. Finally, software code to calculate the energy usage and Total Equivalent Warming Impact (TEWI) value of different refrigeration technologies was also written in Matlab. All three software codes were integrated, and a graphical user interface was developed. Using the graphical user interface, a user can tailor a cold chain scenario by adding different cold chain blocks. Each cold chain block has properties that can be modified. The tool can be used to compare different cold chains with respect to quality, safety, energy usage, and environmental impact

    Bidirectional regulation of bone formation by exogenous and osteosarcoma-derived Sema3A

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    Semaphorin 3A (Sema3A), a secreted member of the Semaphorin family, increases osteoblast differentiation, stimulates bone formation and enhances fracture healing. Here, we report a previously unknown role of Sema3A in the regulation of ectopic bone formation and osteolysis related to osteosarcoma. Human recombinant (exogenous) Sema3A promoted the expression of osteoblastic phenotype in a panel of human osteosarcoma cell lines and inhibited the ability of these cells to migrate and enhance osteoclastogenesis in vitro. In vivo, administration of exogenous Sema3A in mice after paratibial inoculation of KHOS cells increased bone volume in non-inoculated and tumour-bearing legs. In contrast, Sema3A overexpression reduced the ability of KHOS cells to cause ectopic bone formation in mice and to increase bone nodule formation by engaging DKK1/β-catenin signalling. Thus, Sema3A is of potential therapeutic efficacy in osteosarcoma. However, inhibition of bone formation associated with continuous exposure to Sema3A may limit its long-term usefulness as therapeutic agent

    Home Range and Ranging Behaviour of Bornean Elephant (Elephas maximus borneensis) Females

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    BACKGROUND: Home range is defined as the extent and location of the area covered annually by a wild animal in its natural habitat. Studies of African and Indian elephants in landscapes of largely open habitats have indicated that the sizes of the home range are determined not only by the food supplies and seasonal changes, but also by numerous other factors including availability of water sources, habitat loss and the existence of man-made barriers. The home range size for the Bornean elephant had never been investigated before. METHODOLOGY/PRINCIPAL FINDINGS: The first satellite tracking program to investigate the movement of wild Bornean elephants in Sabah was initiated in 2005. Five adult female elephants were immobilized and neck collars were fitted with tracking devices. The sizes of their home range and movement patterns were determined using location data gathered from a satellite tracking system and analyzed by using the Minimum Convex Polygon and Harmonic Mean methods. Home range size was estimated to be 250 to 400 km(2) in a non-fragmented forest and 600 km(2) in a fragmented forest. The ranging behavior was influenced by the size of the natural forest habitat and the availability of permanent water sources. The movement pattern was influenced by human disturbance and the need to move from one feeding site to another. CONCLUSIONS/SIGNIFICANCE: Home range and movement rate were influenced by the degree of habitat fragmentation. Once habitat was cleared or converted, the availability of food plants and water sources were reduced, forcing the elephants to travel to adjacent forest areas. Therefore movement rate in fragmented forest was higher than in the non-fragmented forest. Finally, in fragmented habitat human and elephant conflict occurrences were likely to be higher, due to increased movement bringing elephants into contact more often with humans
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