Browsing by Author "Abdullah Al Mamun"

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Analysis of a simply-supported thick composite beam with stiffened lateral ends
(Department of Mechanical Engineering, 2014-05) Abdullah Al Mamun; Ahmed, Dr. S Reaz
This thesis deals with the analysis of stress and displacement fields of a mixed boundaryvalue problem of fiber-reinforced composite materials. More specifically, the elastic field of a thick stiffened simply-supported composite beam is investigated using an efficient analytical scheme based on displacement-potential field formulation. In the present displacement-potential approach, the elastic problem of composite materials is formulated in terms of a single potential function of space variables, which is defined in terms of the displacement components of plane elasticity. Accordingly, all the parameters associated with the solution, namely stress, strain and displacements are expressed in terms of the same potential function, which eventually reduces the plane problem to the determination of the potential function from a single partial differential equation of equilibrium. The solution of the equilibrium equation is obtained in the form of infinite series, the coefficients of which are determined by appropriately satisfying the boundary conditions at different edges of the beam. Analytical expressions of the elastic field of the simply-supported beam are derived in terms of the potential function using Fourier series. Solutions are obtained for two different types of stiffeners (axial and lateral stiffeners) at the opposing lateral ends of the beam. Both the isotropic as well as fiber-reinforced composite materials are considered for the present analysis. Some of the practical issues of interest, like the effects of beam aspect ratio and stiffeners are discussed in relation to the composite beam. The analytical scheme is then extended to determine the fiber-orientation dependent stresses in stiffened simply-supported beam. Two limiting cases of fiber orientation ( = 0o and 90o) are considered for a wide range of beam aspect ratio. In an attempt to verify the reliability and accuracy of the analytical scheme developed, the present potential function solutions are compared with the corresponding solutions obtained by classical beam theory and verified with two standard computational methods of numerical techniques. The four solutions are found to be in excellent agreement with each other for all the cases of stiffeners and fiber orientations considered, which eventually establishes the soundness and appropriateness of the analytical scheme developed.
Exploring the perceptions of the teachers and students on english language learning at junior secondary level in Rangamati
(University of Dhaka, 2016-10-30) Abdullah Al Mamun
This study explored both teachers and students’ perception, views, motivation and attitude on English language learning as a foreign language at junior secondary level in Rangamati; a hilly area of Bangladesh. To achieve the objectives of the study, a mixed method approach has been applied where variety of methods and data collection strategies such as FGD, Questionnaire and Interview have been used. Data of the study were collected from 6 English in Action intervention (a DFID funded English language development programme implemented in Bangladesh) secondary schools in Rangamati Sadar upazilla. Data were collected from 359 junior secondary students through an adapted 5-point Likert scale questionnaire and focus group discussion. An in depth interview was used to collect data from 6 English language teachers of 6 secondary schools. Collected data were analysed both statistically and narratively. Findings of the study revealed that both traditional and communicative approaches are simultaneously practiced in English language classroom though curriculum recommends the use of communicative approach only. In most of the cases, the teachers’ and students’ perceptions toward teaching-learning activities of English language contradict with communicative approach. On the other hand, in the process of teaching-learning English language in comparison to plain land both the teachers and students of this area are struggling more because of their ethnic identity, language, culture, school and residential environment and geographical nature. At the same time, different types of integrative and instrumental motivations are working as stimulus for learning English as an international language. Finally, the study shed some light on teachers and students’ perception on learning English that are very important to know to get desired outcomes. Findings of the study led to some important implications for different aspects and practice of English language education that will help the educators, concerned authorities to take proper initiatives to develop teaching-learning process in Bangladesh and other developing countries.
Gender-based vulnerability and adaptive capacity in the disaster-prone coastal areas from an intersectionality perspective
(2024-09-15) Mainul Bari, A.B.M.; Intesar, Anika; Abdullah Al Mamun; Debnath, Binoy; Md. Towfiqul Islam, Abu Reza; Monirul Alam, G.M.; Parvez, Md. Shahin
Households in the coastal areas are more vulnerable to various environmental, social, and economic disruptions in terms of an intersectionality point of view. As a first step in mitigating potential effects on families, knowing how susceptible they are and, ideally, fortifying themselves against existing and potential disruptions is essential. Vulnerability and adaptive capacity could not be uniformly distributed between households owing to gender-based socio-economic disparities and inequities. This research, thereby, examined the vulnerability and adaptive capacity variation between households headed by males and females in the two coastal areas of an emerging economy like Bangladesh. This study utilized the Evaluation-based on the Distance from Average Solution (EDAS) method and Boosted Regression Trees (BRT) technique to conduct the analysis. The EDAS method has been used to analyze the adaptive capacity index. Using BRT, an innovative approach in the area, we showed that male and female-headed households are different in terms of their capability to adapt. The findings from this study suggest that the households led by females are more vulnerable than those headed by males in the study region across a variety of dimensions (social, health, economic, housing, and land ownership) from an intersectionality perspective. The study findings can provide a new outlook for the decision-makers in the coastal region on the vulnerability and adaptive capacity differences among the residents and thus lead to more efficient disaster management practices.
Smart Eyes Glass A Blind Assistant
(North South University, 2019) Pretom Das Hira; Abdullah Al Mamun; Shakhawat Hossain; Dr. Shahnewaz Siddique
A blind person cannot see, so he faced many problems in daily life. He needs an assistant to assist him. But it is quite difficult to manage a person who help throughout the whole day. So, we need such a smart assistant that is not a human being but it helps more than smart way. Here is our solution: Smart eyeglasses! It will be a perfect smart assistant for a blind person for reading a written article, recognizing money and colors, detect a human in front of him. And it gives the output through headphones which connect with his ears.