2,663 research outputs found
ゴンドワナ・Barapukuria石炭盆地 （北西バングラデシュ）の多層・長壁式採炭に伴う地質学的災害危険分析：数値シミュレーションに基づく評価
No full text琉球大学博士（学術）This dissertation connects the Boundary Element Method (BEM) and Finite Element Method (EFM) with its practical applications to recognize underground mining related geo-environmental hazards associated with the Gondwana Barapukuria Coal Basin of northwest Bangladesh. .A total of three models are presented to recognize ground movement and water inrush/inflow. The study uses both FEM and BEM numerical analyses to evaluate stress redistribution, strata failure, and water inflow enhancements that result from the coal extraction operations. It is apparent from the fracture heights that large amounts of caving would occur towards the roof due to the multi-slice extraction of coal, and finally would be linked with the water-bearing Dupi Tila Formation. For the case of seam gas outburst, three models are also presented in this study. Model A assumes horseshoe-shaped geometry, model B assumes trapezoid-shaped geometry, and model C assumes horseshoe-shaped geometry coupled with a roof fall-induced cave generated by the break-up of rock materials along the vertical dimension of an igneous dyke. From these simulation results, it is thought that the extension of the dyke-induced perturbation zone toward the roof, floor, and rib sides of the entry roadway initially creates small tensional cracks that gradually grow into large-scale tensional features. These features could also be responsible for high concentrations of gas, which are emitted into the mine from fractured coals due to insufficient mine ventilation and low atmospheric pressure. Mining-induced fault reactivation and its impacts on main conveyor belt roadway have been focused as an adverse geo-hazard for the safe operation of the mine. The simulation results illustrate that the mining-induced redistribution of stresses causes significant deformation within and around the two faults_ Failure trajectories that extend towards the roof and left side of fault indicate that mining-induced reactivation of faults is not sufficient to generate water inflow into the mine. However, if movement of strata occurs along the fault planes due to regional earthquakes, and if the faults intersect the overlying Lower Dupi Tila aquiclude, then liquefaction could occur along the fault zones and enhance water inflow into the mine. Considering all geo-hazards, I recommend for rethinking about coal bed methane (CBM) resource potential rather than underground mining of Barapukuria coal basin.学位論
A paradox of the world population stabilization policy
No full textMd. Mahmudul Alam, Rafiqul Islam Molla, Khondaker Mizanur Rahman, Md. Wahid Mura
Climate Change and Agricultural Growth: An Examination of the Link in Malaysia
No full textMd. Wahid Murad, Rafiqul Islam Molla, Mazlin Bin Mokhtar, Md. Abdur Raqui
Water Access in Changing Climate in Bangladesh: A Study of Social Impacts on Women Who Manage Household Water
No full textAccess to water depends on the availability of water but climate change impact such as sea level rise, increase frequency and intensity of cyclone, floods, and erratic rainfall reduces the availability of water by either polluting water sources or damaging water supply and management infrastructure. Women are the worst victims of climate change regarding water access as they are primarily responsible for managing water for the household. This study focuses on how climate change is responsible for reducing water access and subsequently bear on women in addressing the water crisis problem. The study found that women face challenges in access to water that affect them in terms of less time, physical and mental health problems, sexual assault/harassment, violence in the household, reduce their income, children’s education, early marriage, divorce, and make more difficult to perform their responsibility. Initiatives should be taken to enhance water access for women on a priority basis
Structure of genes of the L locus in flax controlling resistance to rust / by Md. Rafiqul Islam
No full textBibliography: 136-146v, 146 leaves, [9] leaves of plates : ill. (some col.) ; 30 cm.Thesis (Ph.D.) -- University of Adelaide, Dept. of Agronomy, 198
Impact of climate-induced extreme events and demand–supply gap on water resources in Bangladesh
No full textAgriculture, domestic, and industry rely on water resources systems for fulfilling water demand, while water resources systems face both climate-induced extreme events and management and governance problems. These constraints lead to a mismatch between demand and supply of water for those sectors. This study applies central tendency and variability to analyze data and mixed methods approach to interpret the result. From 1999 to 2019, the growth rates of population, gross domestic product, and urban population are -1.354, 6.084, and 3.70%, respectively, contributing to increased water demand. However, the average groundwater depletion increased from 2.455 km(3) (1989-1990) to 4.9016 km(3), while the average flood-affected areas enhanced by 8,644 km(2) in 2014-2018 compared to 1987-1991. Furthermore, salt-affected areas incremented by 222,810 ha in 2009 contrasted to 1973, whereas the mean wind speed of cyclones increased by 30.02 km in 2015-2020 compared to 1988-1995. The mean sea-level rise increased by 16.8 and 169.2 cm in 1995-2000 compared to 1979-1983 in Cox's Bazar and the Char Changa station, respectively. The Mann-Kendall test was applied to detect the trend. This study urges policymakers, water experts, and academics to promote rainwater harvesting that is sustainable to govern rainwater and mitigate water and economic poverty
Does Rainwater Harvesting Contribute to Fight Climate Change and Women Empowerment in Bangladesh?
No full textAgriculture, domestic, and industry rely on water resources systems for fulfilling water demand while water resources systems face both climate-induced extreme events and management and governance problems. These constraints lead to a mismatch between demand and supply of water for those sectors. This study applies central tendency and variability to analyze data and mixed methods approach to interpret the result. Throughout 1999-2019, the growth rate of population, gross domestic product, and urban population is 1.354%, 6.084%, and 3.70% correspondingly, contributing to increased water demand. However, average groundwater depletion increased from 2.455km3 (1989-1990) to 4.9016km3 while average flood-affected areas enhanced by 8,644km2 in 2014-2018 compared to 1988-1993. Furthermore, salt-affected areas incremented by 2,22,810ha in 2009 contrasted to 1973, whereas the mean wind speed of cyclones increased by 30.02km in 2015-2020 compared to 1988-1995. The mean sea-level rise increased by 16.8cm and 169.2cm in 1995-2000 compared to 1979-1983 in Cox’s Bazar and Char Changa station, respectively. The current approach to address the mismatch may not be effective as a long-term solution due to climate change and geographical context so that this study urges policy makers to shift their focus on water sources for addressing the gap between water demand and supply in Bangladesh. This study will create attention of policymakers, water managers, water experts, and academics for further study in adaptation with climate extreme events which impact on water resources, damage social economic and enviornmnetal assets, and displaced people. It also urges finding and accommodating a sustainable approach to reducing the water demand-supply gap. This study is relevant for various government organizations dealing with water resources management, policymakers, and professionals in water resources management and governance. Sustainable water resources management is one of the significant factors in achieving sustainable development goals and alleviating poverty. Since sustainable development is a multidimensional concept, it is influenced by different factors like water access, poverty, socioeconomic development. Rainwater collection and use are ways to ensure sustainable water resources management and increase water access where formal water suppliers fail to address the water crisis. This research explores what key factors influence the economic benefit of rainwater harvesting using Ordinary Least Square regression on primary data collected from 1040 households at a subdistrict of southwestern Bangladesh. Six factors have been measured the price of water, age of rainwater harvesting, the total cost of rainwater harvesting, storage capacity, number of children, and income. It is the first kind of empirical research that connects rainwater harvesting, economic advantage, and econometric analysis. The empirical result shows that income (1.253***), storage capacity (49.425***), price of water (80669.9***), age of rainwater harvesting (8740.16***), and total cost (1.649***) have positive correlation with economic benefit while the number of children (-3501.90***) has a negative. It concluded that economic benefit from rainwater harvesting could be improved by including in water management policy or different policies for rainwater harvesting, particularly for the rain-intensive country. Moreover, it can be a tool to alleviate poverty and achieve sustainable development goals through increasing water access. However, context specificity and multidimensionality is the limitation of this study. Water security has been long connected with facilitating women empowerment that is more crucial in developing countries. The rising water demand may hamper water security, leading to a constraint empowerment process. Women empowerment is rising in Bangladesh, but the connection between water security through rainwater harvesting and women empowerment is the first study in this circumstance. It may provide an alley to determine the connection between water security ensured by rainwater harvesting and empowerment. This quantitative study explored the survey data of 1051 households to measure the possibility of economic, social, and political empowerment through water security. The result shows that economic, social, and political empowerment has a positive and statistically significant relation with water security, but context specificity indicates that interpretation of the findings is not uncomplicated. Moreover, male household head, income, number of family members, and operating rainwater harvesting negatively influence water security level while the cost to build up rainwater harvesting infrastructure, storage capacity, and land ownership positively influences water security. Based on the results, policies and programs that stimulate women's empowerment need more understanding and strategies concerning water security and empowerment for gender equality and achieve sustainable development goals five and six
Modeling and Performance Analysis of 1.55 µm Quantum Well Edge Emitting Laser Based on InGaN
No full textThis thesis is submitted to the Department of Electrical and Electronic Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Electrical and Electronic Engineering, January, 2012.Cataloged from PDF Version of ThesisIncludes bibliographical references.The advent of research work for longer wavelength 1.55 µm lasers, InGaN advances fast due
to its compatible band gap energy and excellent properties. These lasers are well-suited and
ideally matched with the existing fiber optic infrastructures as well as bandwidth of the
modern ultra speed communication system with substantially tower attenuation, transmission
losses, waveform degradation and dispersion penalty. In this thesis, a study is conducted on
the design of 1.55 µm InGaN quantum well laser to investigate the effects on various design
parameters for the better performance and to deduce an optimum laser structure. The study is
separated into stages; it begins with an extensive review on the lasers in chronological order,
followed by the development of the laser model with the analysis of band structure
interpolation model as well as laser characterization Next, the thermal and equivalent circuit
modeling is presented to investigate the temperature effect and electrical properties of the
laser respectively. Careful analysis of the band profile by solving one-dimensional time
independent Schrodinger and Poisson's equations using finite difference method is
4 demonstrated. The thermal and circuit-level laser modeling is also developed by solving the
respective rate equations. Matlab as well as PSPICE simulation programming languages are
employed for numerical analysis.
The simulation and analysis results reveal the energy separation between different band and
subbands for quantum well laser. It is observed that the electron density in conduction band is
1018cm-3
It is also found a better efficiency (59%), reduced threshold current density
(1,1 19A/cm2), and bias voltage (1.1 volts), high optical gain (9,000 cm-1), moderate material
gain (3,660 cm-1) and modal gain (45 cm-1). In addition, threshold current, 5.1 mA, output
power, 5mW, and slope efficiency, 0.695W/A are obtained. Further understanding of the
laser performance with different ambient temperatures the thermal effects has been analyzed.
It is found that the threshold current has been increased to 5.5mA at the same ambient.
Finally, the circuit level equivalent circuit demonstrates the electrical properties of the laser.Md. Jahirul Isla
Improvement of BER Performance of DS-OCDMA in Dispersive Fiber Medium
No full textThis thesis is submitted to the Department of Electrical and Electronic Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Electrical and Electronic Engineering, March 2011.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 63-68).Among the dispersion mechanisms fiber group velocity dispersion (GVD) and polarization
mode dispersion (PMD) are the key limiting factors for high-speed, long length and highperformance
fiber optic communications, especially, for optical code division multiple access
(OCDMA). In this study, an analytical model is proposed to evaluate the bit error rate (BER)
performance of direct sequence (DS) OCDMA with cascaded in-line optical amplifiers in
presence of GVD, PMD, and their compensations using fiber Bragg grating (FBG) and
frequency advanced higher-order PMD vectors. Optical orthogonal codes (OOC) are used as
address sequence, and Intensity modulation direct detection technique is employed in a single
mode fiber optic system operating at 1550nm. Optoelectronic conversion is performed by an
avalanche photodiode (APD) in an optical correlator receiver. The system BER performance is
determined on account of receiver, optical amplifier, and multiple access interference (MAI)
noises. The power penalty suffered by the system is determined at BER of 10 as a function of
system parameters.
The BER performance of the proposed OCDMA system is investigated in two steps. The
impact of GVD and its compensation is studied in the first step taking into account of super
Gaussian and Hyperbolic-Secant-shaped OOC's as address sequence. In the second step the
influence of PMD and its compensation is analyzed under GVD-induced penalty compensated
condition. The results obtained in the first step indicate that the performance of proposed
system severely degrades due to interchip interference caused by GVD-induced spreading and
overlapping of short duration chips which limits the fiber length, chip rate, and number of
simultaneous user. The numerical results also indicate that the system BER performance is
highly dependent on the chipshape, and suffers minimum penalty when Hyperbolic-Secantshaped
chip is used instead of super-Gaussian-shaped chip. The system performance is further
determined in presence of FBG-based compensator. It is found that about 90% of the GVD induced
penalty can be compensated depending on the compensator parameters.
In the second step, the BER performance of proposed DS-OCDMA system is evaluated in
presence of PMD and PMD compensation using Gaussian shaped OOC's. The system BER
performance is found to degrade more at higher chip rate, and longer fiber length due to the
effect of PMD. However, employing PMD compensation significant improvement of the
system performance is found by third-order PMD compensation with respect to first-, and
second-order compensations.Md. Jahedul IslamMaster of Science in Electrical and Electronic Engineerin
Secretary, Ministry of Finance vs Md. Masdar Hossain and others
No full text
Purpose
The purpose of this paper is to analyse the legendary decision of the Appellate Division of the Supreme Court of Bangladesh. Apart from this, the author’s aim is to analyse the constitutional interpretation done by the Higher Judiciary of the Country. Another aim of this note is to simplify the decision of this case for the understanding of the mass people and law students.
Design/methodology/approach
To conclude this paper, both qualitative and analytical methods have been used.
Findings
In this paper, a summarized fact of the case has been presented. In addition to that, decision of the High Court Division in the Writ petition has been simplified with six simple points. Moreover, major arguments submitted by both the Appellant’s and Respondent’s Lawyers have been summarized. Decision of the Appellate Division has been simplified with 12 simple points along with the reasoning behind the judgement.
Research limitations/implications
In this paper, only the case of Secretary, Ministry of Finance vs Md. Masdar Hossain and Others has been studied and analysed in depth.
Practical implications
This paper will mainly help the Law and Social Science students for simply understanding the decision and the reasoning behind the decision of the case. Apart from that, this case noting will help both academics and legal professionals to study this case within a short period.
Social implications
This paper will help mass people who want to study about this case to simply understand the case in depth. In addition to that, people will get known about the procedure hoe the subordinate judiciary of Bangladesh became independent.
Originality/value
This conceptual paper is the original piece of work and is not under review in any other journal. This paper has not been published previously in any other journal.
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