Improvement of Dynamic Performance of the Grid Connected Photovoltaic (PV) System by Series Compensating Devices

This study proposes the bridge type fault current limiter (BFCL) and series dynamic braking resistor (SDBR) methodologies to enhance the low voltage ride through (LVRT) capability of the PV plant during network faults. This work also focuses on smoothing out the PV power fluctuation due to variable irradiance. To achieve this, the output power of diversely located identical and small PV plants, instead of a big PV plant in a certain area, is integrated. Simulations performed through the Matlab/Simulink software shows that the terminal voltage obtained from the proposed protection schemes maintains the grid code, and hence the PV systems need not to be disconnected from the grid during fault. It is also seen that smoothing of PV power fluctuation is possible by the proposed integration method. Also, the size of the energy storage required for the diversely located PV system is smaller than that for a big PV plant

Teacher Educators and Trainee Teachers' Attitude toward Online Teacher Education Courses

The purpose of the study was to explore the attitude toward Online Teacher Education Courses (OTECs). To that end, this study was carried out over the teacher educators and trainee teachers of Bangladesh Open University. Here, teacher educators represent the faculty members of the School of Education (SoE) of Bangladesh Open University (BOU), and trainee teachers represent the Master of Education (M.Ed.) and Bachelor of Education (B.Ed.) students of BOU. A mixed research approach with triangulation was used to conduct the study with a descriptive survey, two Focus Group Discussions (FGDs), and one key personnel interview. Data were collected from a total of 602 teacher trainees (182 were M.Ed. students and 420 were B.Ed. students) and 12 teacher educators, selected through multiple sampling techniques. The  data revealed that the teacher educators and trainee teachers had a positive attitude towards online courses since the mean score of faculty members, M.Ed., and B.Ed. students of BOU were 3.60, 381, and 3.81, respectively. Considering all these aspects, this study suggested that SoE/BOU needs to decide rationally to shape its future Online Teacher Education Courses (OTECs). This research contributes to the basement of new knowledge through an explorative study with all the possible stakeholders covering the whole country of interest

A STUDY ON CAUSES OF KNITTING MACHINE STOPPAGES AND THEIR IMPACT ON FABRIC PRODUCTION

Knitting machine stoppages cause loss of fabric production. The smooth running of knitting machine depends on yarn quality, knitting machine conditions and knitting production conditions. Knitting machine stops due to different causes. In this work it was found that the causes of stoppages are yarn breakages, set-off, machine cleaning and fabric roll cutting, yarn joining, needle breakages and oil problem. The major cause of knitting machine stoppage was machine cleaning and fabric roll cutting. It occupies almost 40.38% of total stoppage time. This cause lead to the production loss of 43.48 kg of fabric. Similarly, yarn breakages, set-offs, and other causes like yarn joining and needle breakages occupied 20.19%; 7.69% and 31.7% of total stoppage time respectively. The knitting machine was stopped for total 312 minutes among 24 hours or 1440 minutes of running due to all of the causes. The causes, combindly led to production loss of 107.66 kg of fabric in 24 hours. Due to the all of the causes total 21.66% of fabric production loss was realized

Wild Fodder Yielding Plants in the Protected Areas of Bangladesh

Wildlife habitat is degrading worldwide due to myriads of biotic and abiotic reasons. The governments across the world countries are trying to halt the degradation through declaring protected areas (PAs) with potential wildlife habitats and strengthening conservation initiatives. These measures are expected to uphold the richness and diversity of the fodder yielding plants. But there is a dire necessity of information on composition and overall status of the fodder yielding plants for continuous monitoring of these habitats. Moreover, the potentiality of the protected areas can also be judged based on the composition and richness of fodder yielding plants. Having all these in mind, we assessed the composition and conservation status of the fodder yielding plants of all habit forms from three recognized protected areas named Chunati Wildlife Sanctuary, Dudhpukuria-Dhopachari Wildlife Sanctuary, and Madhupur National Park. The study indicated the presence of 306 fodder yielding plant species of all habit forms in the three studied protected areas. This chapter describes the composition, status, habit forms, and nature of occurrences of the wild fodder yielding plants which is expected to be highly helpful in wildlife habitat monitoring and undertaking specific measures for multiplication and conservation of fodder yielding plants

Performance evaluation of coal dust and wood powder ash as alternates of conventional filler in the asphalt concrete

Mineral fillers provide a significant role in the Marshall properties of hot mix asphalt for paving applications. The article's goal is to assess the suitability and effectiveness of two minerals (coal dust and wood powder ash) used as fillers in asphalt concrete. Chemical composition test using X-ray fluorescence indicated a high content of SiO2, Fe2O3, and Al2O3, which encouraged us to select the coal dust and wood powder ash as mineral fillers for further investigation. A total of 90 cylindrical Marshall Specimens, made with different percentages (i.e., 4%-8%) of coal dust, wood powder ash, and conventional stone dust filler were prepared to assess the performance of individual filler within the asphalt concrete mix. And after that, volumetric characteristics such as density, stability-flow test, air void, and voids in mineral aggregates have been analyzed to evaluate the effectiveness of every sample and, afterward, to find out the optimum asphalt content. Finally, the optimum asphalt content for every filler material was ascertained, and subsequently, Marshall properties were checked again to assess the optimum filler content in the mix that satisfy all the standard criteria. The overall Marshall properties for both fillers were within the acceptable limits. Though the optimum asphalt content was higher for coal dust than wood powder ash and stone dust, the wood powder ash showed better durability than coal dust. All mixtures have been found to have better resistance to deformation, fatigue, and moisture-induced damages; however, 4% coal dust and 6% wood powder ash satisfied most of the Marshall criteria than other percentages

To Study the Activity of Few Radionuclides Using Biokinetic Model

Activity of the radionuclides and the doses because of sharp intake of 1 Bq of a long lived radionuclide (133Ba) and a short lived radionuclide (99mTc) have been calculated based on the human alimentary tract model (HATM) through ingestion. Due to ingestion maximum radiation dose is deposited in the alimentary tract, which consists of seven tissue compartments, e.g., Oral Cavity (OC), Esophagus (OP), Stomach (ST), Small Intestine (SI), Left Colon (LC), Right Colon (RC) and Rectosigmoid Colon (RSC). The radiation dose deposited in 2 of the organs within the tract, e.g., ST, SI and 3 other organs outside of the tract, e.g., liver, right lung (RL) and left lung (LL) are considered. Tissue masses of alimentary tract for Bangladeshi people of different age groups were taken for the calculation. The age groups are such as new born, 1 yr, 10 yrs, adult male, adult female for the first type considering 2 organs and <20 yrs male, 21-40 yrs male, 41-60 yrs male, > 60 yrs male, <20 yrs female, 21-40 yrs female, 41-60 yrs female for the rest 3 organs. The time required to get an insignificant value of activity depends more on decay constant of the radionuclides than the rate constant of the organs. The activity values became insignificant approximately after 5 hrs, 8 hrs, 60 hrs and 90 hrs in ST, SI respectively for long lived radionuclide. These time values are relatively shorter for short lived radionuclide than those for other radionuclides

Analysis of the Socio-Economic and Psychological Status of the Widows: A Study on Jhenidah District

This paper aims at analyzing the socio-economic status of widows in the Jhenidah district and evaluate the impact of socio-economic status on the widows livelihood in society For achieving the purpose of the study the researchers collected the primary data by a structured questionnaire and data were gathered from sixteen respondents from Jhenidah district by a convenient sampling method The researchers in this study found that widows suffer from multiple social problems and restrictions Moreover the widows are feeling discouraged in their lives though they earn a satisfactory figure since dissatisfaction arises from the multiplicity of social problems for the widow

THE CHALLENGES OF SECONDARY LEVEL BUSINESS EDUCATION IN BANGLADESH

This paper discusses challenges of secondary level business education in Bangladesh. In particular, it explores the challenges related to curriculum, pedagogy, infrastructure and assessment systems in school. We looked at the existing facilities in schools that teach business education, teaching strategies used in the classrooms as well as the perceptions of teachers and students towards business education.Using an online survey, data was collected from 101 respondents who are secondary level school teachers. Findings reveal that challenges are mainly related to curriculum, pedagogy, infrastructure, and assessment system. However, infrastructure and students’ attitude-related challenges are the greatest challenges. In addition, we find that most of the business studies classes are attended by more than 40 students, contributing to issues related to pedagogy, infrastructure and assessment. The study recommends that the present curriculum, infrastructure, and assessment procedure of business education at the secondary level need to be upgraded for effective secondary level business education in the country. Artikel ini membahas tantangan pendidikan bisnis tingkat menengah di Bangladesh. terkait dengan kurikulum, pedagogi, infrastruktur dan sistem penilaian di sekolah, khususnya dalam hal fasilitas sekolah untuk pendidikan bisnis, strategi pengajaran yang digunakan, serta persepsi guru dan siswa terhadap pendidikan bisnis. Metode yang digunakan survei online dari 101 guru sekolah menengah. Temuan mengungkapkan bahwa tantangan terutama terkait dengan kurikulum, pedagogi, infrastruktur, dan sistem penilaian. Namun, infrastruktur dan sikap siswa merupakan tantangan terbesar. Selain itu, jumlah siswa yang cukup besar, lebih dari 40 siswa, berkontribusi pada masalah yang berkaitan dengan pedagogi, infrastruktur, dan penilaian. Studi ini merekomendasikan bahwa kurikulum, infrastruktur, dan prosedur penilaian pendidikan bisnis di tingkat menengah perlu ditingkatkan efektivitasnya di negara tersebut

Lymphoid Polyposis in an Adult Male- A Case Report

Benign lymphoid polyposis is a rare histologic entity and should not be confused with malignant disease of the colon and rectum. We present a case of lymphoid polyposis in the intestine in a 26 years old male patient who was admitted for the treatment of faecal fistula. He had history of appendectomy, followed by ileostomy four years back. Physical examination revealed multiple faecal fistulae in the right lower abdomen. Right-sided hemicolectomy was done. Gross examination showed multiple polyps through out the specimen; the junction between caecum and ascending colon was found partially stenosed. Microscopy revealed polypoid structures consisting of multiple lymphoid follicles with prominent germinal centers. A stenosed area represented probable fistulous tract within the fibrosis. The final diagnosis was lymphoid polyposis based on clinical, gross and microscopic features. Keywords: Lymphoid polyposis; Faecal fistula. DOI: http://dx.doi.org/10.3329/bsmmuj.v4i2.8643 BSMMU J 2011; 4(2):119-12