Distributed Generation as Voltage Support for Single Wire Earth Return Systems

Key issues for distributed generation (DG) inclusion in a distribution system include operation, control, protection, harmonics, and transients. This paper analyzes two of the main issues: operation and control for DG installation. Inclusion of DG in distribution networks has the potential to adversely affect the control of voltage. Both DG and tap changers aim to improve voltage profile of the network, and hence they can interact causing unstable operation or increased losses. Simulations show that a fast responding DG with appropriate voltage references is capable of reduction of such problems in the network. A DG control model is developed based on voltage sensitivity of lines and evaluated on a single wire earth return (SWER) system. An investigation of voltage interaction between DG controllers is conducted and interaction-index is developed to predict the degree of interaction. From the simulation it is found that the best power factor for DG injection to achieve voltage correction becomes higher for high resistance lines. A drastic reduction in power losses can be achieved in SWER systems if DG is installed. Multiple DG can aid voltage profile of feeder and should provide higher reliability. Setting the voltage references of separate DGs can provide a graduated response to voltage correction

Distributed Generation Control using Protection Principles

In a distribution system, it is essential to maintain the voltage variation within a specified limit for satisfactory operation of connected customers' equipment. Normally, this goal is achieved by controlling the operation of compensating devices, such as load tap changing transformers, shunt capacitors, series capacitors, shunt reactors, and static VAr compensators. However, technical and regulatory developments are encouraging a greater number of small generator units, known as Distributed Generation (DG), and this has the potential to significantly affect voltage control systems. This paper presents an adaptive voltage control technique which incorporates DG systems into the voltage control system. The control scheme uses On-load Tap Changing Transformer (OLTC) and DG for voltage corrections, both are driven by advanced Line Drop Compensators (LDC). At the substation, the LDC is employed to control step up or step down decisions of the OLTC, while another LDC will be used at DG connection point to set DG parameters. Also, for a more cost-effective system, voltage control action coordination is proposed using magnitude grading and time grading. The control approach is tested on a modified distribution system with load variations that are stochastic in time and location. The results show that the integration of these magnitude grading and time grading, protection principles have considerably reduced the DG energy required to achieve the desired control

Factors affecting the adoption of aquaculture technologies by the farmers

Purpose of the study was to ascertain the extent of adoption of aquaculture technologies by the farmers as well as constraints faced by them in adopting the aquaculture technologies. The study also explored its relationships with the selected characteristics of the farmers. In addition, an attempt was also made to determine some selected attributes of the technologies and their relationships with the adoption by the farmers. The study was conducted with the farmers of 10 upazilas of greater Mymensingh district who were the beneficiaries of three NGOs viz. SARA, ORD, and GRAMAUS. There were 351,241 and 249 beneficiaries under SARA, ORD and GRAMAUS, respectively who adopted the aquaculture technologies under DSAP. About 25% farmers from each of the three NGOs were selected for the study. The total sample size was 212. Pre-designed and pre-tested interview schedules were used for collecting data from the farmers. Field data were collected from the farmers during August-September, 2004. Pearson product moment correlation co-efficient were computed in order to explore the relationships of the selected characteristics of the farmers as well as selected attributes of technology with the adoption of aquaculture technologies by the farmers. The same statistical test was used to determine the relationships between the selected characteristics of the farmers and their constraints in adopting the aquaculture technologies

I) The synthesis of optically active thiols and related compounds ; and, 2) The oxidation of some thiocarbonates

Imperial Users onl

環境計測のための低コスト集積型センサチップ

富山大学・富生命博甲第76号・Md. Abul Kashem・2015/09/30・★論文非公開★富山大学201

The Bangladeshi Consumer Behavior and Attitude Toward Superstores

Superstores introduced a whole new experience in the shopping of daily necessities. They offered quality products at a stable price in safe and clean environment in order to survive and achieve profitability. Although there are many factors which relate to customer satisfaction, but most of previous empirical research in this field tended to emphasize on quality products, products variety and special products, location, hygienic environment, hassle free shopping and freshness , competitive price, service and layout of the store. The purpose of the study is to identify the role of each of the factors to respond to customer requirements to satisfy customers and what and how they behave in the market place toward these factors. The totality of their movement toward the factors and attitude, the researcher liked to demonstrate here.  The questionnaires were developed from many previous researches. The data was collected from 50 customers of 5 superstores in Chittagong. The result of this study shows that the factors have positive relationship with customer satisfaction those in terms ensure store loyalty. Therefore, the superstores should consider product and store service factors as the foundation to satisfy customer and to improve service quality as an add-on value to customer. Keywords: Superstore, Consumer Behaviour, Attitude, Demographic factors

System biology of alcoholism: Understanding of the consequences of the metabolism in brain cells

The addictive drug ethanol represents a serious universal health and social problem. Alcohol abuse and dependency have been increasing in many countries worldwide. Chronic use of alcohol leads to metabolic abnormalities and damage to the brain, which can result in severe cognitive dysfunction and addiction. Areas of the brain such as prefrontal cortex (PFC), the white matter, the hippocampus (HP), the cerebellum and the striatum are particularly vulnerable to the effects of alcohol. The striatum (ST), a region of brain closely associated with addiction mechanisms, is commonly divided into two regions, dorsal (DS) and ventral striatum (VS); the DS comprising caudate nucleus (CN) and putamen (P) while the VS is constituted mainly by nucleus accumbens (NAc). Neuroimaging analysis indicates that microstructural degradation is occurring in alcohol-affected brains and the abnormalities may be correlated with altered locomotor activity, aggressive behavior, changes in reward/aversion-related learning, deficient motor coordination, disturbances in procedural learning and memory. The NAc is strongly implicated in drug addiction but current evidence suggests that DS has also a significant role in this process. One of the aims of the project is to carry out comparative study of the sub-regions of human alcoholic striatum using two omics technologies (proteomics and metabolomics). There were no differences in the levels of dopamine (DA), 3,4-dihydrophenylacetic acid (DOPAC), serotonin (5HT), homovanillic acid (HVA), 5-hydroxyindoleacetic acid (HIAA), histamine, L-glutamate (Glu), -aminobutyric acid (GABA), tyrosine (Tyr) and tryptophan (Tryp) between the DS (CN and P) and VS (NAc) in control brains. Choline (Ch) and acetylcholine (Ach) were higher and, norepinephrine (NE) is lower, in the VS Overall. Alcohol-affected ST had lower levels of neurotransmitters except for Glu (30% higher in the alcoholic ventral striatum). Ratios of DOPAC/DA and HIAA/5HT were higher in alcohol-affected ST indicating an increase in the DA and 5HT turnover. Glutathione was significantly reduced in all three regions of alcohol-affected ST. The pattern of changes of 13 neurometabolites in alcoholic sub-regions relative to their respective control was similar. In order to investigate correlations between the alcohol-related changes in metabolites and and altered protein expressions, the author has selected a single sub-region of ST for a global proteomics study. By analysing CN tissues, 25 unique proteins were found to be differently expressed in alcohol-affected tissue 9 relative to control. From the identified proteins two were dopamine-related proteins and one a GABA-synthesizing enzyme glutamate decarboxylase (GAD) 65. Two proteins that are related to apoptosis and/or neuronal loss (BiD and amyloid-β A4 precursor protein-binding family B member 3) were increased. These results suggest that neurotransmitter metabolism and systems possibly related to neuroprotective mechanisms in both the DS (CN and P) and the VS (NAc) are significantly influenced by long-term heavy alcohol intake associated with alcoholism. Amongst the mechanisms mediating the effects of alcohol oxidative stress may have produce a particularly significant impact and could make a strong contribution to the microstructural damage. It has been known that alcohol can have a particularly damaging effect on the PFC and the HP regions of the fetus/developing/adolescent brain. The change imparted at those stages of development could be irreversible resulting in lasting deficits in a range of personality traits and impacting decision making, memory and learning. The HP is a significant place of neurogenesis and a source of neural stem cell (NSC). These can differentiate into neurons, astrocytes and oligodendrocytes and constitute building blocks of the developing central nervous system. They can also contribute to brain repair at later stages of development and, possibly, even in adulthood. On current evidence, alcohol reduces neurogenesis but little or no tangible information is available on the actual biochemistry and/or the fate of NSC. In the present experiments, the NSC obtained from rat embryos were exposed to various concentrations of ethanol (25 to 100 mM) for up to 96 hours. The cell numbers were found to be reduced in the presence of ethanol but only at the higher concentrations (50 and 100 mM). There were no apparent dramatic changes in the morphology of the cells but the numbers of neuron-like (MAP2-positive) cells were reduced by ethanol in a dose-dependent manner. In proteome analysis of alcoholic cells, a total of 28 proteins were altered in 50 mM ethanol relative to ethanol-free control. Of these proteins some were constituents of cytoskeleton, others were involved in transcription/translation, energy metabolism, signal transduction and oxidative stress. Two of the proteins identified as altered were nucleophosmin (NPM) and dead-end protein homolog 1 (DND1). These were further studied by immunological techniques in cultured neurons and astrocytes. NPM decreased and DND1 increased in both alcohol affected neurons and astrocytes cells

Recent Issues in Bangladesh-India Relations: A Bangladeshi Perspective

What are the recent issues in Bangladesh-India relations that determine the nature of the bilateral relations? This article is an attempt to investigate this question. It argues that there are a number of pertinent issues that determine the nature and state of Bangladesh-India relations. In this context, security, trade, visa, cricket, power, connectivity remain as vital issues. The article recommends that in this age of shared peace, security and prosperity, Bangladesh-India needs to explore and utilise the untapped potentials

Health and Hygiene Practice of Tea Garden Workers in Bangladesh

This paper is focused on health and hygiene practice of tea garden workers in Bangladesh It is generated out of a study conducted in a tea garden of Sylhet City in Bangladesh The tea garden workers are mostly vulnerable as they deprived from proper health hygiene and sanitation They are badly treated in every respect of their life To explore the health and hygiene facilities culture of practice diseases due to not having proper practices and health supports from Government and Non-government organizations the study approach was qualitative in nature and case study method considered as method By using purposive sampling method fifteen 15 respondents were selected from the study area Semi-structured interview schedule and observation technique were used to collect primary data from the respondents It was found that majority of the tea garden workers and their family members are now aware about health and hygiene practice They are suffering from different types of general and chronic illnesses like jaundice diarrhea skin etc Most of the family of tea gardens drink tube-well water and use the same for bathing washing and other household purpose