43 research outputs found

    Comsol Modelling of Uniform Corrosion of Used Nuclear Fuel Canisters

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    Uniform corrosion of copper can occur in spent nuclear fuel canisters placed in deep geological repositories (DGR). To estimate the minimum thickness for safe design of canisters, it is necessary to analyze the corrosion rate. Copper Corrosion Model (CCM) has been used to model the corrosion process taking into account processes including adsorption/desorption, precipitation/dissolution, oxidation, and parameters including oxygen concentration, chloride, moisture and associated rate constants. In this work, CCM has been incorporated in COMSOL and validated with CCM. Once validated, the COMSOL model was used to examine the sensitivity of various parameters with respect to copper corrosion. It was found that initial chloride concentration, adsorption/desorption of cupric ions are parameters that most effect copper corrosion. The developed model can be used to simulate the uniform corrosion process under DGR conditions with more complexity including variation in temperature, saturation and pressure, and aid in the design of copper canisters

    Effects of Aluminium Exposures on Growth, Photosynthetic Efficiency, Lipid Peroxidation, Antioxidant Enzymes and Artemisinin Content of Artemisia annua L.

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    Acid soils are widely distributed at a global scale; under acidic conditions, the solubility of aluminium (Al) increases and the elevated concentration of toxic Al3+ in soil solution seriously limits crop production. There is no information on the effects of aluminium (Al) on Artemisia annua L., which is a most important antimalarial plant in the recent time being artemisinin; responsible for its antimalarial activity. In this report, we describe the effects of Al contamination on growth, photosynthetic efficiency, membrane damage, antioxidant enzyme activities and changes in artemisinin content in A. annua. Al addition to the soil medium significantly reduced the yield and growth of the plants. Lower values of net photosynthetic rate, stomatal conductance, internal CO2 and total chlorophyll content were observed as a result of different Al concentrations applied. The activities of nitrate reductase (NR) and carbonic anhydrase (CA) were also found to be hampered by Al exposure to the plants. Al enhanced lipid peroxidation rate (TBRAS content) and activated the activities of catalase (CAT), peroxidase (POX) and superoxide dismutase (SOD) enzymes in the treated plants. The elicitation in the endogenous ROS levels, due to the Al treatments, was also noticed in the present study. Furthermore, enhanced artemisinin content and yield was obtained at 0.10mM concentration of soil applied Al. Our study provides evidence that excess Al in soil hamper the growth and yield, slow down the activities of NR and CA, induce lipid peroxidation and antioxidant enzymes but a low level of Al-toxicity can induce artemisinin content in A. annua plants.Key words: Aluminium (Al); Artemisia annua L.; Artemisinin; Lipid peroxidation; Reactive oxygen species (ROS)Tariq Aftab et al. Effects of Aluminium Exposures on Growth, Photosynthetic Efficiency, Lipid Peroxidation, Antioxidant Enzymes and Artemisinin Content of Artemisia annua L. J Phytol 2/8(2010) 23-37

    Local-Partial Signal Combining Schemes for Cell-Free Large-Scale MU-MIMO Systems with Limited Fronthaul Capacity and Spatial Correlation Channels

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    Cell-free large-scale multi-user MIMO is a promising technology for the 5G-and-beyond mobile communication networks. Scalable signal processing is the key challenge in achieving the benefits of cell-free systems. This study examines a distributed approach for cell-free deployment with user-centric configuration and finite fronthaul capacity. Moreover, the impact of scaling the pilot length, the number of access points (APs), and the number of antennas per AP on the achievable average spectral efficiency are investigated. Using the dynamic cooperative clustering (DCC) technique and large-scale fading decoding process, we derive an approximation of the signal-tointerference-plus-noise ratio in the criteria of two local combining schemes: Local-Partial Regularized Zero Forcing (RZF) and Local Maximum Ratio (MR). The results indicate that distributed approaches in the cell-free system have the advantage of decreasing the fronthaul signaling and the computing complexity. The results also show that the Local-Partial RZF provides the highest average spectral efficiency among all the distributed combining schemes because the computational complexity of the Local-Partial RZF is independent of the UTs. Therefore, it does not grow as the number of user terminals (UTs) increases

    Enhancement of laser absorptivity in metal by laser surface modification

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    An innovation which currently in 4th TRL aims to improve laser-material interaction by increasing absorption of laser energy through surface roughness using laser surface modificatio

    Impact Of Excessive Nitrogen Fertilizers On The Environment And Associated Mitigation Strategies.

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    The soaring rise in the anthropological production of nitrogen (N) fertilizers has been notable in the field of crop production. Despite several advantages the world is deriving from the use of reactive N, many environmental hazards including water and soil acidification, pollution of groundwater surface and other water mineral resources and accelerated ozone depletion have arisen as a result of the recurring use of excessive environmental N. The purpose of this paper is to highlight the impact of N in the environment. In addition, mention is made of management practices, such as manure storage and handling solutions, livestock management, pasture management for reduced N losses, balanced N application rates, proper irrigation strategies, efficient N cycling at the field level, runoff, drainage and wastewater management and other mitigation strategies. Conclusively, the use of Varian’s Mathematical model, a model that dutifully delineates system theory in deterring over-fertilization will be considered

    Viability of the novel process of indirect laser brazing

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    Brazing is a 5000 year old joining process which faced still with the advanced joining challenges that exist today [1]. In laser brazing components are joined together by heating above the melting point of a filler metal placed between them. It provides unique advantages over other joining methods, including the ability to joint dissimilar material. Indirect laser brazing is a novel process which able to joint dissimilar metals with minimal formation of a brittle intermetallic compound (IMC) layer than conventional furnace brazing. In this study the viability of indirect laser brazing process was investigated between Ti6Al4V and 316L stainless steel

    Effect of laser frequency and focal length on copper surface temperature during laser heating

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    Laser heating is a process that uses laser as a heat source. In this paper, the copper surface temperature during the laser heating process was studied by controlling the laser frequency and focal length. The laser heating experiment was conducted using a fiber laser marking machine and irradiated with a constant 27 W laser power within a duration of 51 s. The laser frequency and focal length were varied from 100 to 300 kHz and −3 cm to +3 cm, respectively. Meanwhile, laser surface modification (LSM) was performed on the copper rod surface to enhance the laser energy absorption. Furthermore, the defocusing modes for laser heating were used to analyze the variation of temperature. The focus point of the focal length for this experiment was set up at 18.4 cm from the focal plane and denoted as 0. Laser frequency and focal length were found to play an important role in increasing the surface temperature during laser heating since it affects the heat input delivered to the materials. It was found that the surface temperature reaches a higher degree, 879.2 °C with the combination of 200 kHz laser frequency at focal length

    Legal, Accounting and Tax Aspects of the Selected Non-profit Organisation

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    Import 04/11/2015Práce je zaměřena na občanská sdružení a jejich transformaci na spolek, popsání účetnictví v neziskové organizaci a také na jeho zdaňování. Pomocí analýzy právních předpisů, je popsán postup při transformaci občanského sdružení na spolek a také jsou zde uvedeny dokumenty, které jsou pro transformaci potřeba, dále znázorňuje účetnictví a zdanění ve vybrané neziskové organizaci. Práce je řešena v souvislosti s novou právní úpravou občanského zákoníku a jiných předpisů.The work is focused on civil associations and their transformation to the association, describe the accounting in non-profit organisation and also to its taxation. Through the analysis of legislation, a process is described for the transformation of the civic association in the association and documents, which are for the transformation of the need for, further illustrates the accounting and taxation in the selected non-profit organization. The work is addressed in the context of the new legislation of the civil code and other regulations.117 - Katedra účetnictvívelmi dobř

    A community-based cluster randomised controlled trial in rural Bangladesh to evaluate the impact of the use of iron-folic acid supplements early in pregnancy on the risk of neonatal mortality: The Shonjibon trial

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    Abstract Background Iron-deficiency is the most common nutritional deficiency globally. Due to the high iron requirements for pregnancy, it is highly prevalent and severe in pregnant women. There is strong evidence that maternal iron deficiency anaemia increases the risk of adverse perinatal outcomes. However, most of the evidence is from observational epidemiological studies except for a very few randomised controlled trials. IFA supplements have also been found to reduce the preterm delivery rate and neonatal mortality attributable to prematurity and birth asphyxia. These results combined indicate that IFA supplements in populations of iron-deficient pregnant women could lead to a decrease in the number of neonatal deaths mediated by reduced rates of preterm delivery. In this paper, we describe the protocol of a community-based cluster randomised controlled trial that aims to evaluate the impact of maternal antenatal IFA supplements on perinatal outcomes. Methods/design The effect of the early use of iron-folic acid supplements on neonatal mortality will be examined using a community based, cluster randomised controlled trial in five districts with 30,000 live births. In intervention clusters trained BRAC village volunteers will identify pregnant women & provide iron-folic acid supplements. Groundwater iron levels will be measured in all study households using a validated test kit. The analysis will follow the intention to treat principle. We will compare neonatal mortality rates & their 95% confidence intervals adjusted for clustering between treatment groups in each groundwater iron-level group. Cox proportional hazards mixed models will be used for mortality outcomes & will include groundwater iron level as an interaction term in the mortality model. Discussion This paper aims to describe the study protocol of a community based randomised controlled trial evaluating the impact of the use of iron-folic acid supplements early in pregnancy on the risk of neonatal mortality. This study is critical because it will determine if antenatal IFA supplements commenced in the first trimester of pregnancy, rather than later, will significantly reduce neonatal deaths in the first month of life, and if this approach is cost-effective. Trial registration This trial has been registered with the Australian New Zealand Clinical Trials Registry (ANZCTR) on 31 May 2012. The registration ID is ACTRN12612000588897
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