The development of manganite-based materials for thermoelectric power generation

CaMnO3 is one of the promising n-type thermoelectric (TE) materials for power generation applications due to its superior TE properties and stability at high temperature. Nevertheless, efficiency is still the major limiting factor for its common use. It is essential to understand the mechanisms associated with carrier and phonon transports for further enhancing the TE properties of this material. The main focus in this dissertation was to improve the TE properties of CaMnO3 by optimizing microstructure using different synthesis techniques and doping technology. It was found that the microstructure have remarkable influence on the electrical properties and thermal transport properties. The relative density of the sample was identified to be 86 (±3)% to achieve the high TE performance irrespective of their synthesis technique (solid state reaction, coprecipitation). The experimental results may provide a guideline for the variation in performance of this material system under different processing. In addition, it was found that doping in either Ca or Mn site with higher valence elements increases the carrier concentration, leading to the reduction of electrical resistivity ρ and Seebeck coefficient S. Furthermore, doping decreased the thermal conductivity κ of CaMnO3 up to a critical doping level, which is believed to associate with the decrease of phonon mean path and doping-induced MnO6 octahedral distortion. It was found that distortion mainly affects the equatorial bonds in the a-c plane in manganite system. Substitution of Bi was found to be effective to reduce κ due to its large mass difference with Ca. Doping in both Ca and Mn site was also studied and found that the appropriate doping element and doping concentration are the determining factors to obtain positive influence from the codoping technology. Bi was found as an effective substituent for a critical doping content (x=0.03) which simultaneously provides the high power factor (4.67×10-4 W m-1 K-2 at 423 K) and low κ (1.4 W m-1 K-1 at 973 K). These led to obtain maximum ZT value ~0.25 at 973 K for Ca0.97Bi0.03MnO3, which is three times larger than that for undoped CaMnO3

The Value and Effectiveness of Feedback in Improving Students’ Learning and Professionalizing Teaching in Higher Education

There is a great importance of feedback in improving learning experience for the students. This has also significant effect in professionalizing teaching in the higher education level. However, feedback is considered as a difficult issue in this arena. Most of the lecturers are still continuing with the tradition form of feedback. This form of feedbacks often unable to satisfy the students in improving their learning experience. It is high time for the lecturers to re-think about the feedback providing process. They should avoid traditional way of proving feedback towards the students. This paper comes with some modern and technology based way of proving feedback which can eventually help students in improving student learning experience. This can also help in professionalizing the teaching of lecturers in higher education.

A Comparative Study on Dyeing Properties of Hemp and Cotton Fiber

In this study, a mixed bi-functional reactive dye was applied to the cotton and hemp woven fabrics. Their dyeing and fastness properties were compared. From the results, it was observed that the cotton fabric exhibits better exhaustion and levelness than hemp woven fabrics. The build-up and fastness properties of the two woven fabrics appeared to be almost similar

The Impact of Revised Wage Rate on Firm’s Competitiveness in the Ready Made Garment Sector of Bangladesh: A Case Study Comparison Between Large vs SME Garment Manufacturers

The objective of the paper was to critically analyse the impact of revised minimum wage rate on the competitiveness of different size garment manufacturers in Bangladesh. In doing so the paper adopted a case study approach and incorporated data from multiple case study companies. Notably, the paper aims to cover three main areas: industry conditions and its implications on profitability, the critical resources which are giving the large case study firms a competitive advantage and finally the impact of institutional change brought about by the Rana Plaza incident on different case study firms. Using relevant literature from these three areas the paper proposed 3 hypotheses which were in turn tested and re-developed by using the primary data collected from case study companies. The findings from the research highlighted that the profitability of the garment industry became particularly low only after the imposition of minimum wage; however the profitability in mid-market segment is still comparatively higher. The study also identified the two critical resources that are helping the large case study firms to strategize better in relation to tackling the impact of minimum wage, which were “Industrial Engineering Department” and “Vertically Integrated Supply Chain”. Finally the study identified the change in institutional paradigm and stringent monitoring brought about by Rana Plaza incident had a more significant impact for the SME’s due to issues such as decoupling which were much easier to pursue previously. Finally the paper also outlined some strategies which SME case study firms could adopt in order to minimize the impact of minimum wage. Notably, the revised minimum wage increase was only implemented from December 31st 2013 and there hasn’t been much academic work in relation to the context; therefore the study aims to provide a first-hand overview of the situation prevailing after the minimum wage which could be in turn used for further research in the area

Clonal Propagation of Aegle marmelos through IBA Treatment for Sustainable Nutritional and Medicinal Supply for the Poor People of Agrarian Bangladesh

The study was carried out at the Agriculture research field of Patuakhali Science and Technology University (PSTU) from March to October, 2017 to explore rooting performance of Aegle marmelos (Bael) through clonal propagation by stem cutting under 3 different doses of IBA (Indole Buetaric Acid) and planted in the perforated plastic tray filled with coarse sand and gravel placed in the non-mist propagator. The experiment was laid out following a Randomized Complete Block Design (RCBD) with 4 treatments and 4 replications (blocks). The treatments were T0= control, T1 = 0.2% IBA, T2 = 0.4% IBA, T3 = 0.8% IBA. The rooting ability of cuttings was significantly influenced by the application of IBA. The highest rooting percentage (60%) was recorded in A. marmelos both with 0.2% and 0.4% IBA followed by 0.8% IBA (40%). Longest root (3 cm) was recorded with 0.4% IBA followed by 0.2% IBA (1.2 cm). The maximum root number (2.25) and root diameter (2 mm) obtained from cuttings treated with 0.8% IBA followed by 0.4% IBA (2 and 1.9 mm respectively). Survival percentage of the cutlings (the rooted cuttings) significantly enhanced by exogenous rooting hormone (IBA) application. The highest survival percentage (73.5%) was observed for the cuttings treated with 0.4% IBA followed by 0.8% IBA (68.5%). Findings of the present study reveal that the plant species is highly amenable for clonal propagation by stem cuttings using low-cost non-mist propagator. Considering rooting percentage, root number and and root length, 0.4% IBA treatment may be recommended for mass production of quality planting stocks. Farmers and nursery owners can be trained up regarding this low cost non-mist propagation system of Aegle marmelos for cultivation of the species in homestead agroforestry or in fruit orchards for sustainable nutritional and medicinal supply for the poor people of agrarian Bangladesh

Antibiotic-Resistant Escherichia coli Isolated from Duck Cloacal and Tap Water Samples at Live Bird Markets in Bangladesh

Antibiotic resistance is a growing concern all over the world. The current study sought to identify antimicrobial resistance (AMR) patterns and antibiotic-resistant genes in Escherichia coli (E. coli) isolated from seemingly healthy ducks and neighboring tap water sources at three separate live bird markets (LBMs) in Chattogram, Bangladesh. A total of ninety cloacal swab samples of Khaki Campbell ducks and fifteen water samples from nearby tap water sources were collected from three LBMs. Several cultural and molecular tests were conducted to determine  E. coli contamination. The disk diffusion technique was used to evaluate the antibiotic sensitivity of E. coli isolates to 12 different antibiotics. For each isolate, a Multiple Antibiotic Resistance (MAR) index was calculated. The resistance genes were detected using a polymerase chain reaction (PCR) assay. The overall prevalence of E. coli in feces and tap water samples was 64.4% (58/90, 95% CI 54.1-73.6) and 100% (15/15, 95% CI 76.1-100), respectively. Both fecal and water isolates showed 100% resistance to ampicillin, tetracycline, and nalidixic acid. Resistance to other antibiotics was also found to be high. Multidrug- resistance (MDR) was unveiled in all fecal (58/58) and water (15/15) isolates. MAR index ranged from 0.33 to 0.67 in all recovered isolates. Both fecal and water E. coli isolates harbored blaTEM, tetA, sul1, and sul2 genes. The resistance genes in MDR E. coli in live bird markets might transmit from ducks to humans and they, therefore local authorities should consider this issue a major public health risk

Genetic sources and loci for wheat head blast resistance identified by genome-wide association analysis

The emergence and spread of wheat blast caused by fungal pathogen Magnaporthe oryzae pathotype Triticum is a threat to global wheat production. The resistance level and genetic loci for blast resistance in Chinese germplasm remain unknown. A panel of 266 bread wheat accessions from China, CIMMYT-Mexico and other countries was screened for head blast resistance under 12 field experiments in Bolivia and Bangladesh. Subsequently, a genome-wide association study was performed to understand the genetic basis of wheat blast resistance. The average blast index of all the accessions was 53.7% ± 12.7%, and 10 accessions including Chinese accessions Yumai 10 and Yu 02321 showed moderate to high levels of blast resistance, accounting for only 3.8% in the panel. Fifty-eight significant SNPs clustered in a 28.9 Mb interval on the 2AS/2NS translocation region, explaining phenotypic variation between 10.0% and 35.0%. The frequency of the 2AS/2NS translocation in the Chinese accessions was as low as 4.5%. These results indicated that the 2NS fragment was the only major locus conferring resistance to wheat blast in this panel, and the resistant and moderately resistant lines identified could be deployed in breeding

Analysis of IP Mltimedia Subsystem for 3G Networks

The IP Multimedia Subsystem is seen as the promising solution for the next generation multimedia communication. The IP Multimedia Subsystem will make Internet technologies almost anywhere, anytime and on any device such as email, web, instant messaging, presence and videoconferencing. Presence is one of the most important basic services in IMS. It is the service that allows a user to be informed about the reachability, availability and willingness to communicate with other user. Push to talk over Cellular (PoC) is one more service in IMS that allows users to engage in immediate communication with one or more users. Instant Messaging (IM) is the service that allows a user to send some content to another user in near real time. In this thesis work, we have discussed overall IMS architecture and identity the major issues to improve the existing protocols in IMS for better system performance.Our work is centered on Presence service, Push to talk over Cellular, Instant Messaging and IMS session setup. In this thesis three possible session establishment scenarios in a mobile environment is compared by using an analytical model. The other problem areas in optimizing presence service, dimensioning a PoC service and analyzing service rate of IM relay extensions in IMS are identified

Comparative study of treatability of atrazine using treated and untreated wood charcoal

Removal of atrazine from aqueous phase was attempted in the range of 0–10 mg/l using various methods viz. adsorption by both treated and untreated wood charcoal. Atrazine was analyzed using gas chromatograph with OV-17 poropak stainless steel column. Although activated carbon is the major abatement methodology for many pesticides, treated wood charcoal showed higher removal efficiency than that of untreated wood charcoal. At pH 6.0, treated wood charcoal shows more than 90% removal efficiency

Management of butachlor bearing water by waste tyre rubber granules

Scarcity of drinking water is one of the major problems in Bangladesh. Use of waste tyre rubber granules as a filter media has been identified to treat butachlor-bearing water. Waste tyre rubber granules have been used in a fixed bed column reactor. The experiment has been conducted with 2 mg/l of initial butachlor concentrations for bed depth of 25 cm. It has been found that 1 gm of waste tyre rubber granules can purify 0.021 liter of distilled water and 0.018 liter of tap water having 2 mg/l of butachlor. Experimental data has been found to have a better correlation with BET isotherm based theoretical breakthrough curves. Service time obtained from BDST approach and experimental breakthrough curves are found to very close. Efficiency of the system has been found 80% and 73% based on contact approach and adsorbent usage approach, respectively