Development of Novel Multilevel Inverter with Reduced Power Switches

In recent days the usage of multilevel inverters became very essential and crucial especially on high power consuming sites. The advantages on the modularity, failure management, reliability and the waveform with less harmonic distortion at the output made the multilevel inverter to gain more attention in the current industry. Even though, multilevel inverters serving the industry with more significant advantages however they do have drawbacks such the usage of high number of power switches in their circuit and this leads to high manufacturing cost and also increase the complexity of the circuit structure. In this paper a new 9 level multilevel inverter topology has been analyzed. The proposed topology has considered factors such as reducing the power switches, reducing the total harmonic distortion and reducing the complexity of the structure

Cultivation of Microalgae Using Compost as Nutrient Source for Biodiesel Production

Cultivating microalgae for biodiesel production requires substantial amount of nutrient such as nitrogen and phosphorous. In this research project, it focuses on the use of low-cost compost or organic fertilizer as the main nutrient source for microalgae cultivation. It contains high value of nutrients without any contamination that can support microalgae growth. In this research, Chlorella Vulgaris species growth was investigated. The main objective of the experiment will be to study the effect of cultivation parameter such as amount of compost nutrients, duration of illumination, pH value and colour filter towards the growth of microalgae. The growth of the microalgae will be measured by using the spectrophotometer. After it have achieved stationary phase, the microalgae will be dried and biomass collection takes place. The last method will be lipid extraction using Soxhlet extractor and also transesterification reaction with Fatty Acid Methyl Ester (FAME) analysis. The analysis will be done by using gas chromatography-mass spectrometry analysis

Non-Gaussian velocity distributions in excited granular matter in the absence of clustering

The velocity distribution of spheres rolling on a slightly tilted rectangular two dimensional surface is obtained by high speed imaging. The particles are excited by periodic forcing of one of the side walls. Our data suggests that strongly non-Gaussian velocity distributions can occur in dilute granular materials even in the absence of significant density correlations or clustering. When the surface on which the particles roll is tilted further to introduce stronger gravitation, the collision frequency with the driving wall increases and the velocity component distributions approach Gaussian distributions of different widths.Comment: 4 pages, 5 figures. Additional information at http://physics.clarku.edu/~akudrolli/nls.htm

Convexity properties of loss and overflow functions

We show that the fluid loss ratio in a fluid queue with finite buffer $b$ and constant link capacity $c$ is always a jointly convex function of $b$ and $c$. This generalizes prior work [6] which shows convexity of the $(b,c)$ trade-off for large number of i.i.d. multiplexed sources, using the large deviations rate function as approximation for fluid loss. Our approach also leads to a simpler proof of the prior result, and provides a stronger basis for optimal measurement-based control of resource allocation in shared resource systems

Neuroimaging, Cognitive and Metabolic Profiles in Children with Hypoglycaemia

Background: Glucose is a major fuel for brain function, and persistent and recurrent hypoglycaemia of any aetiology can cause brain injury. Children with hyperinsulinaemic hypoglycaemia (HH) are at a high risk of brain injury, as the inappropriate secretion of insulin during hypoglycaemia inhibits lipolysis thereby reducing the availability of ketone bodies (KB) that are an important source of alternate fuel for the brain during hypoglycaemia. In contrast children with ketotic hypoglycaemia (KH) are believed to be neurologically protected, due to the presence of abundant ketone bodies during hypoglycaemia. However, in both these groups of children, a comprehensive assessment of the neurocognitive profile with correlation to neuroimaging is not available. Aims: The aims of this thesis are 1. To understand the magnitude and rate of ketone body response during a diagnostic fast between children with KH and a ‘control’ group (children with suspected or previous history of hypoglycaemia that were subsequently normoglycaemic on the diagnostic fast). 2. To investigate and compare the neurocognitive profiles of children with HH and KH (used as a control group), and to correlate the profile of deficits in the HH group to the underlying structural abnormalities. The studies on children with KH (biochemical, neurocognitive and neuroimaging) were utilised to understand the neuroprotective role of KB during hypoglycaemia. Methods: 30 children with KH and 74 children from the ‘control’ group underwent a diagnostic fast with measurements of plasma glucose, lactate, catecholamines and serum insulin, cortisol, growth hormone, non-esterified fatty acids (NEFA) and 3-βhydroxybutyrate (ketone body) concentrations at the beginning, middle and end of fast. The neurocognitive profile of 21 children with HH was compared to a group of 14 children with KH, using a combination of standardised tests to investigate IQ, memory, attention, academic attainment, movement, emotion and behaviour. The structural integrity of the brain was evaluated using conventional neuroradiological assessments, hippocampal volumetry and diffusion tensor imaging (DTI). Results: Fasting studies have shown that children with KH demonstrate a significant increase (87% per hour) in the rate and magnitude of 3-βhydroxybutyrate concentrations relative to ‘controls’. Cortisol concentrations are a significant predictor of KB concentrations at the end of the fast. The performance of KH children as a group was within the normal range for the neurocognitive measures. However four children in the KH group scored in the borderline (77-79) and low average range (81-84) for full scale IQ, and memory scores in one KH child was lower than predicted by 19 points. Neuroimaging revealed small hippocampi in one child, focal white matter lesions in two children and diffuse white matter lesions in two children with KH. Children with HH underperformed significantly (relative to KH and standard population means) in the tests for intelligence (especially perceptual reasoning), memory, and sustained attention and manual dexterity. Memory impairments in children with HH did not correlate with hippocampal pathology. However, analysis of DTI studies has revealed the presence of white matter microstructural deficits that correlate with IQ and perceptual reasoning indices in these (HH) children. The genu and splenium of the corpus callosum were highlighted as specific white matter regions vulnerable to injury in the HH group. Conclusions: Children with hypoglycaemia are at risk of white matter injury. Children with HH manifest widespread cognitive deficits that are partly explained by the white matter microstructural deficits noted in the DTI studies. The increased rate and magnitude of KB response in KH group during fasting supports increased metabolic utilisation and a glucose sparing effect. However some chidren with KH in this study exhibit white matter injury and a wide variation in the neurocognitive scores is also noted, indicating the presence of neurocognitive impairment in certain children with KH

A Review on Gamification in e-learning: Effects and Challenges

Information technology has brought us a great deal of technological advancement, opening up endless possibilities for distance education. E-Learning platforms make it possible to connect people around the globe. Using the various technologies that are available, Gamification enhances the performance of e-learning platforms. Gamification of e-learning platforms helps in providing an engaging learning experience for users of all ages. Applying gamification in a non-gaming environment motivates students and also keeps them engaged in learning. This paper summarizes various game elements such as points, leader boards, badges, provided to the users for better e-learning experience by gamifying the environment and discussing the impact of gamification

Study of changes in serum levels of creatine kinase and liver enzymes in organophosphorus poisoning and it’s prognostic significance

SUMMARY: 1) In this study which included 110 patients of organophosphorus poisoning brought to Chengalpattu Medical College hospital, 62.72% were males and 37.27% were females. 2) Majority of the patients were in the age group of 20 -40 which constituted 61% of the study population. 3) The severe poisoning group predominantly belonged to older population with a mean age 51.48 years when compared to mild 36 years and moderate 32.02 years. 4) Most common compound consumed was chlorpyrifos (32.72%) followed by methylparathion (19.09%) and dimethoate (17.27%). 5) Most common presenting symptom is abdominal pain (86.36%) and most common presenting sign is miosis (89.09%). 6) Mean CPK, SGOT and SGPT values in case of mild, moderate and severe case of OPC poisoning is 76.5, 38.63 and 45.0 respectively. 7) Mean CPK, SGOT and SGPT values in case of moderate severity in case of OPC poisoning is 249.24, 71.53 and 70.44 respectively. 8) Mean CPK, SGOT and SGPT values in case of severe poisoning is 843.68, 157.54 and 138.32 respectively. 9) Mean CPK, SGOT, SGPT values in case of respiratory failure, intermediate syndrome and death is (815.10, 157.84, 141.57), (857.2, 159.4, 143.40), (940.81, 183.37, 160.37) respectively