Design and implementation of 30kW 200/900V LCL modular multilevel based DC/DC converter for high power applications

This paper presents the design, development and testing of a 30kW, 200V/900V modular multilevel converter (MMC) based DC/DC converter prototype. An internal LCL circuit is used to provide voltage stepping and fault tolerance property. The converter comprises two five level MMC based on insulated gate bipolar transistors (IGBTs) and metal oxide semiconductor field effect transistor (MOSFET). Due to low number of levels, selective harmonic elimination modulation (SHE) is used, which determines the switching angles in such a way that third harmonic is minimized whereas the fundamental component is a linear function of the modulation index. In addition, instead of using an expensive control board, three commercial control boards are embedded. This is required to implement the sophisticated DC/DC converter control algorithm. Simulation and experimental results are presented to demonstrate the converter performance in step up and down modes

Historical Perspective and Evaluation of Advertising Firms in Bangladesh

Advertising has become a part of the economic & social fabric of a nation. It provides information about the product, service, ideas etc. It influences the choices we make. A descriptive framework has been made in order to understand the history of advertising in Bangladesh, categories of advertisement, advertising prices of different mediums, major clients of advertisement in our country, and legal aspect of advertising in Bangladesh. This study adopts with qualitative in nature. This research enables researchers to understand the history, trends and influential aspect of an advertisement in our country. After all these research will unveil the overall trends and quality of advertisement in Bangladesh. Key Words Advertising History, Above Line category, Below Line Category, Advertising Agencies, Channels, Advertising Budget, Discount of Advertising, Advertising Tariff, Clients of Advertising Agency, Code of Advertising

Trends of Large Scale Retailing in Bangladesh

Bangladeshi large scale retail stores are changing along with the change of time. So this paper tries to find out the current trends of Bangladeshi large scale retail stores. This study adopts with qualitative in nature. Here, women are coming outside from the four walls and work with male hand in hand. So they are busy. People want to save time. The large scale retail stores can enjoy competitive advantage if they emphasize on fresh product, variety products, and fixed price, neat & clean, availability of exceptional products, card facilities, central A/C and promotional offer.Keywords: Retail, adulterated food, Variety of products, Bangladesh

Towards the Quantification of Estrone and 17β-Estradiol Conjugates in Dairy Cattle Urine Sorptive Stir Bar Extraction and Gas Chromatography-Mass Spectometry

The global concern regarding the presence of compounds with estrogenic properties in the environment has grown significantly. Endocrine-disrupting compounds (EDCs) are environmental pollutants that disrupt the endocrine systems of both wildlife and humans. Estrogens, with their potent estrogenic effects, are particularly noteworthy among the various substances with endocrine-disrupting properties. They are of concern due to their prevalence in the environment, especially due to dairy waste contamination. These lipophilic compounds can accumulate in livestock fat tissues, potentially entering the human food chain. Sulfated forms of estrone and β- estriol, which exhibit a higher degree of saturation than their non-conjugated counterparts, have also been detected in the environment. The persistence of these saturated conjugated estrogens in the environment raises significant environmental and health concerns, as they possess estrogenic activity and can lead to greater human endocrine disruption than non-conjugated estrogens. While free estrogen forms in the environment have been extensively studied, their conjugated counterparts have received less attention. In this study, we present a chromatographic method for the quantification of estrone and β- estriol and their conjugated forms. Specifically, the gas chromatographic portion of the method involves converting all respective sulfated conjugates to estrone or β-estradiol through acid hydrolysis. We apply this method to quantify estrogen conjugates present in dairy cattle waste and the surrounding dairy farm environment, aiming to monitor their distribution and impact on the ecosystem. This analytical approach contributes to our understanding of the environmental fate of estrogens and their conjugated forms, shedding light on potential risks associated with their presence in the environment and food chain

Departmental Structure & Functions of Advertising Agency in Bangladesh

Advertising is an expanding and important component in the context of any organization. It is a part of marketing strategy that an organization should apply in order to increase the consumer interest and thereby gain on market share. In Bangladesh advertising agencies are not well organized. Three advertising firms named Bitopy, East Asiatic and Interspan were established in 1967. Now the total numbers of advertising agencies are almost seven hundreds. Yet they are more competitive than previous. And new employment opportunity has been created & they have been performing in more professional manner. So it is important to know the structure of each department and functions of advertising agency. This study adopts with qualitative in nature. From the research, other researchers and policy makers will get an insight about the departmental structure and functions of advertising agencies in Bangladesh. Key Words: Departmental Structure, Advertising Agency, Client Service Department, Creative Department, Media Department

Capability analysis of drift-inherent processes: case of nail wire drawing

Purpose: The central purpose of the study is to model the process capability of drift-inherent manufacturing processes by testing the efficacy of a novel approach that filters trend from raw process data before applying statistical process control tools. A secondary aim was to ascertain the intrinsic capability of the process following the filtering.Design/Methodology/Approach: Specifically, the study focused on processes in a nail-wire drawing and tested a method for analysing data from naturally-drifting processes that involves filtering trends from data before applying appropriate tools to verify the state of statistical control and capability of the process. The physical foundation for this work is based on data collected from a nail-wire drawing process A total of 250 data points were gathered over 50 days in two successive instances of 125 points, each spanning 25 days. Data were checked for normality followed by mathematical conditioning to filter out the wear trend before analysis by normal statistical process capability and control chart procedures.Findings: Results show that the proposed method is effective for tracking hidden effects in steadily drifting processes such as those associated with wear. After filtering, the data is found to fall within product specifications, though robust statistical control was still required through appropriate measures.Research Limitation: To investigate the intrinsic nature of the process outside of the process, material wear is assumed to be the sole source of the inherent drift. In processes where several sources of inherent drift are present, this may pose a problem. Additionally, the study focused on just one plant; however, data from other similar plants will be needed to buttress the findings and widen the scope of applicability of the findings.Practical implication: The competitive pressures of today’s marketplace are increasingly forcing companies to place premium emphasis on product quality while aiming at the lowest costs possible. The study recommends continuous and sustained efforts to reduce variation in manufacturing processes to brighten firms’ competitive survival.Social implication: The study will bring new knowledge to metal product manufacturers that can help them deliver high-quality products and value for money to consumers.Originality / Value: New insights afforded by the study’s approach include revelations of otherwise hidden measurement errors as well as undersized finishing-die. Any other out-of-control occurrences can then be more easily tracked and identified and root-cause analysis applied to eliminate them. This is a practical study that seeks to develop an innovative way to monitor the quality of processes whose tracking is made difficult by inherent drift. The easy-to-adopt methodology can be implemented by metal product manufacturers grappling with drift-inherent processes

Effect of nitrogen on seed yield and content and quality of oil of winter grown sunflower (Helianthus annuus L.)

ABSTRACT     Field trials were carried out at Wad Medani and Sennar locations during season 2008 / 09 to investigate the effects of nitrogen levels on growth, seed yield, oil content and quality of two sunflower cultivars. The treatments consisted of three nitrogen levels (86.7, 108 and 129 kg N/ha, applied as urea) and two cultivars (Damazin and Hysun33). Nitrogen at the higher rate (129 kg N/ha) gave higher seed yield. The oil content ranged from 36.3 to 42.9 %. Nitrogen, cultivar and location had no significant effects on oil content. Oleic and linoleic acids were the most dominant fatty acids in the oil. It is recommended to apply 129 kg N/ha to winter grown sunflower to obtain high seed yield

Reproductive biology, artificial propagation and larval rearing of two freshwater eels, Monopterus cuchia and Mastacembelus armatus

Studies on reproductive biology and artificial propagation including larval rearing of freshwater mud eel, Monopterus cuchia and spiny eel, Mastacembelus armatus were attempted. The gonadosomatic index (GSI) of mud eel ranged from 0.41 (August) to 5.52 (June) in males and 0.53 (August) to 7.61 (June) in females. In both cases the GSI showed a peak in June. Fecundity ranged from 228 (TL - 396 mm; W - 78g) to 5510 (TL - 865 mm; W - 630 g). In case of spiny eel, the GSI varied from 0.65 (August) to 8.30 (July) in males and 0.70 (August) to 10.46 (July) in females. GSI showed single peak in July. Fecundity ranged from 570 (TL - 240 mm; W - 30 g) to 10870 (TL - 601; W - 350g). Histology of the testes and ovaries of the eels were carried out to investigate the gonadal development stages during the reproductive months (August to November 2003). In case of male M. cuchia, the secondary primordial germ cells, primary spermatogonium, some spermatogonia A and clone of spermatogonium B in testis were observed in September. In October-males different sized lobules having spermatogonia, spermatocytes and spermatids were observed. In the ovary of M. cuchia, polygonal shaped oocytes were seen during September. The oogonia were reduced with dense and irregular shaped during October. Numerous pycnotic cells were visible during November. In male M. armatus numerous broken lobule walls were found in testes during September. In October, abundant primary germ cells, pycnotic nests of degenerating cells, spermatogonia and spermatids were observed. In females, ovaries had distinct yolk vesicles stage and yolk granules stages in August. In September, the follicular cells of the oogonia were ruptured, shrunk forming irregular shaped in October. Oogonia were also shrunk with thin, irregular shaped structure but broken parts of the ruptured follicular cells were scattered in case of M. armatus. Experimental attempts on artificial propagation indicated that both freshwater eels were difficult to breed using inducing agents like pituitary glands (PG) of 10, 20, 50, 100 and 150 mg per kg of body weight. Same doses were used for both sexes with equal sex-ratio. In both cases, brood fish died at higher doses of injection given at 100 and 150 mg PG/kg bodyweight. However, M. cuchia breed naturally in cisterns when provided with water hyacinths and tunnel in muddy bottom. M. cuchia fed with chopped cooked fish attained a mean weight of 18.75 ± 2.3 g and cent percent survival. While in case of M. armatus best growth by weight (12.0 ± 2.48 g) and cent percent survival were achieved using chopped raw fish. Car tyre was observed as best shelter for attaining the mean weight gain 22.53 ± 2.24 g and cent percent survival of M. cuchia. While PVC pipe was found to be the best shelter for M. armatus, where it attained the mean weight of 12.73 ± 1.88 g and cent percent survival

Workplace Conflict Management Styles: Comparative Study of Indian and Nigerian Employees

Conflict is all pervasive in nature and organizations around the world are not untouched with it. Present study deals with interpersonal conflict in corporate and academic organizations of India and Nigeria on a comparative basis. The study has a non-experimental, descriptive, and quantitative research design, in which a sample size of 103 Indian and 88 Nigerian employees was analyzed through stratified random sampling. Statistical measures like Cronbach’s alpha, One Way Analysis of Variance (ANOVA) and associated Games Howell procedure for multiple comparisons, bivariate correlation and chi square tests were employed to analyze the data. Examination of various independent variables and findings of the research reveal that there is a significant difference in how employees of both the countries differ in their approach to conflict handling. Interpersonal conflict understanding is crucial for smooth functioning of globalized organizations. Managers today are devising innovative handling techniques as conflict poses a great challenge for them. The present study can facilitate the management practitioners in understanding the concept and its implications in Indian and Nigerian context, the two countries which share a very warm, solid and seasoned socio-economic relationship. Keywords: Organizations, Conflict, Handling Style, Employees, India, Nigeri