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Vehicle-Bridge Interaction Simulation and Damage Identification of a Bridge Using Responses Measured in a Passing Vehicle by Empirical Mode Decomposition Method

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Open Journal of Civil Engineering 2023年第4期13卷 742-755页

作者： Shohel Rana md. rifat zaman md. Ibrahim Islam Ifty Seyedali Mirmotalebi Tahsin Tareque Department of Civil Engineering Bangladesh University of Engineering and Technology Dhaka Bangladesh Department of Civil Engineering Atish Dipankar University of Science & Technology Dhaka Bangladesh Department of Civil Architectural and Environmental Engineering North Carolina Agricultural and Technical State University Greensboro North Carolina USA Department of Civil Engineering University of Texas Rio Grande Valley Edinburg Texas USA

To prevent early bridge failures, effective Structural Health Monitoring (SHM) is vital. Vibration-based damage assessment is a powerful tool in this regard, as it relies on changes in a structure’s dynamic characteristics as it degrades. By measuring the vibration response of a bridge due to passing vehicles, this approach can identify potential structural damage. This dissertation introduces a novel technique grounded in Vehicle-Bridge Interaction (VBI) to evaluate bridge health. It aims to detect damage by analyzing the response of passing vehicles, taking into account VBI. The theoretical foundation of this method begins with representing the bridge’s superstructure using a Finite Element Model and employing a half-car dynamic model to simulate the vehicle with suspension. Two sets of motion equations, one for the bridge and one for the vehicle are generated using the Finite Element Method, mode superposition, and D’Alembert’s principle. The combined dynamics are solved using the Newmark-beta method, accounting for road surface roughness. A new approach for damage identification based on the response of passing vehicles is proposed. The response is theoretically composed of vehicle frequency, bridge natural frequency, and a pseudo-frequency component related to vehicle speed. The Empirical Mode Decomposition (Emd. method is applied to decompose the signal into its constituent parts, and damage detection relies on the Intrinsic Mode Functions (IMFs) corresponding to the vehicle speed component. This technique effectively identifies various damage scenarios considered in the study.

关键词： Structural Health Monitoring Vibration-Based Damage Identification Vehicle-Bridge Interaction Finite Element Model Empirical Mode Decomposition

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Post Thyroidectomy Assessment of Intact Parathyroid Hormone for Early Prediction of Hypocalcaemia

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International Journal of Otolaryngology and Head & Neck Surgery 2024年第2期13卷 71-84页

作者： md. Masum Billah Ripon Kumar Sarkar md. Yousuf Ali Saad zaman md. Nazmul Hasan md. Shehab Uddin md. Mosleh Uddin Kazi Shameemus Salam Farzana Binte Abedin Leera Department of Otolaryngology-Head & Neck Surgery Universal Medical College Hospital Dhaka Bangladesh Department of Otolaryngology-Head & Neck Surgery National Institute of Ear Nose and Throat Dhaka Bangladesh Shaheed Ahsan Ullah Master General Hospital Gazipur Bangladesh Department of Otolaryngology-Head & Neck Surgery Cumilla Medical College Cumilla Bangladesh Department of ENT Oncology National Institute of Cancer Research & Hospital Dhaka Bangladesh Department of ENT Outdoor Rajshahi Medical College Hospital Rajshahi Bangladesh Department of Otolaryngology-Head & Neck Surgery Bangabandhu Sheikh Mujib Medical University Dhaka Bangladesh Department of Biochemistry Delta Medical College Hospital Dhaka Bangladesh

Background: As the half-life of intact parathyroid hormone (iPTH) is very low, it reflects parathyroid insufficiency within minutes to hours after total thyroidectomy. Therefore, iPTH level assessment in the postoperative period can be used to predict the development of hypocalcaemia. The optimal time point to measure serum iPTH is important for the accurate prediction of hypocalcaemia. Aim: This paper aims to evaluate the ability of iPTH as an early predictive marker of hypocalcaemia and determine which time iPTH is more able to predict postoperative hypocalcaemia. Method: This prospective observational study was conducted in the Department of Otolaryngology-Head & Neck Surgery, BSMMU, Dhaka, from July 2020 to December 2021, with 67 patients who underwent total thyroidectomy. iPTH levels were measured on the day before the operation and at 1 hour, 4 hours, and 24 hours after the operation. *** levels were measured on the day before the operation and 1st postoperative day. All the data were compiled and sorted properly and were analyzed statistically. Results: Postoperative hypocalcaemia developed in 18 cases, with an incidence of 26.9%. Pearson correlation showed a significant correlation between postoperative iPTH at 1 hr, 4 h, and 24 hr with 1st postoperative calcium value. The Receiver operating characteristic (ROC) curve was processed for the postoperative iPTH at 1 hr, 4 h, and 24 hr. The sensitivity, specificity, cut-off value, and mean AUC found 93.9%, 94.4%, ≤14.0, 0.988;95.9%, 94.4%, ≤09.5, 0.993 and 91.8%, 94.4%, ≤11.0, 0.993 respectively. Conclusion: iPTH can be used as an early predictor of post-thy-roidectomy hypocalcaemia. 4 hr iPTH showed more sensitivity and specificity for a cut-off value near the laboratory reference range.

关键词： Total Thyroidectomy Hypocalcaemia Serum Intact Parathyroid Hormone Early Predictor of Hypocalcaemia

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Microplastics and heavy metals in freshwater fish species in the southwestern region of Bangladesh:An emerging concern for public health

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Emerging Contaminants 2024年第3期10卷 145-157页

作者： Mst Shamima Akter Tapos Kumar Chakraborty Gopal Chandra Ghosh md.Simoon Nice Samina zaman Abu Shamim Khan Department of Environmental Science and Technology Jashore University of Science and TechnologyJashore 7408Bangladesh Environmental Laboratory Asia Arsenic NetworkJashore 7400Bangladesh

Microplastics(MPs)pollution and its associated toxicity raising concerns among scientists as a result of their toxicological impacts on human health and the *** study aims to investigate the microplastics and heavy metals(HMs)contamination in seventeen freshwater fish species collected from the Southwestern region of *** extracted from these species using the hydrogen peroxide digestion method and characterized by Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy(ATR-FTIR).Atomic Absorption Spectrometry(AAS)was used to determine the concentration of HMs in different species for evaluating human health risks.A total of 142 microplastic particles were extracted with an average concentration of 1.13±0.84 items per individual of fish,where the highest microplastics were found in ***(3.43±3.15 items)and lowest in ***(0.14±0.38 items).Identified microplastics were dominated byCu(0.01e1.14;0.50±0.44)>Pb(0.04e0.58;0.22±0.12)>Cd(0.00e0.11;0.03±0.03),*** metals-based human health risk assessment results show that there are no major non-carcinogenic health risks(THI<1),while higher carcinogenic risks are present for consumers.

关键词： Microplastics Edible fish Polymer type Heavy metals Human health risk Bangladesh

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Quality Study of Rice Husk Ash (RHA) Brick Using Neutron Radiography Technique

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Journal of Building Construction and Planning Research 2015年第3期3卷 127-135页

作者： md. Khurshed Alam md. Moniruz zaman md. Al Amin Scientific Information Division Bangladesh Atomic Energy Commission Dhaka Bangladesh Institute of Glass and Ceramic Research and Testing (IGCRT) Bangladesh Council of Scientific and Industrial Research (BCSIR) Dhaka Bangladesh Department of Physic Jahangirnagar University Dhaka Bangladesh

A powerful non-destructive testing (NDT) technique is adopted to study the quality of RHA brick-1 and RHA brick-2. In that case, rice husk ash has been utilized for the preparation of bricks in full replacement of clay. In these studies, homogeneity of elemental distribution, water absorption and size and shape of the pores have been observed. From the studies, it was observed that elemental distribution is very good at various level, large number of porosity is presented with little bit size, initial rate of absorption (IRA) due to first five minutes immersion of water is higher compared to other immersion time (>5 minute), incremental water intrusion area increases very slowly with the increasing immersion time and the water absorption for RHA brick-2 becomes saturated very early than that of the RHA brick-1.

关键词： Neutron Radiography RHA IRA and Water Absorption Behavior

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Assessment of heavy metal contamination in the sur?cial sediments from the lower Meghna River estuary, Noakhali coast, Bangladesh

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International Journal of Sediment Research 2021年第3期36卷 384-391页

作者： Mohammad Abdul Momin Siddique Mahfuzur Rahman Shahriar md.Arifur Rahman md.Rubel Hassan Zeenath Fardous Muhammed Alamgir zaman Chowdhury Mohammad Belal Hossain Department of Oceanography Noakhali Science and Technology University Agrochemical and Environmental Research Division Institute of Food and Radiation Biology Atomic Energy Research Establishment 5. Department of Fisheries and Marine Science Noakhali Science and Technology University Department of Environmental Science and Disaster Management Noakhali Science and Technology University University of South Bohemia in Ceske Budejovice Faculty of Fisheries and Protection of Waters South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses Research Institute of Fish Culture and Hydrobiology

Sediment samples were collected from ten selected sites of the lower Meghna River estuary, and six heavy metals were analyzed with Atomic Absorption Spectrophotometry(AAS) to assess the contamination level and the metals’ association with sediment grain size. The current results revealed that the mean concentrations of the studied metals were ranked in descending order of iron(Fe)(1.29 ? 103 mg/kg) > zinc(Zn)(42.41 mg/kg) > lead(Pb)(12.48 mg/kg) > chromium(Cr)(10.59 mg/kg) > copper(Cu)(6.22 mg/kg) > cadmium(Cd)(0.28 mg/kg). The geo-accumulation, contamination, and pollution load indexes suggested that the lower Meghna river estuary was not contaminated by Fe, Zn, Pb, Cr, and *** mean size of the sediment ranged from 28.92 to 126.2 mm, and the Pearson correlation coefficient showed a significant association between Fe and Pb(coefficient of determination, r2? 0.836; p < 0.05),and no significant correlation was found between individual metals and grain size, indicating no or low influence on the metals distribution.

关键词： Metal pollution Pollution load index Grain size Trace metals

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Secure and efficient implementation of facial emotion detection for smart patient monitoring system

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Quantitative Biology 2023年第2期11卷 175-182页

作者： Kh Shahriya zaman md.Mamun Bin Ibne Reaz Department of Electrical Electronic and Systems EngineeringUniversiti Kebangsaan Malaysia(UKM)Bangi 43600Malaysia

Background:Machine learning has enabled the automatic detection of facial expressions,which is particularly beneficial in smart monitoring and understanding the mental state of medical and psychological *** algorithms that attain high emotion classification accuracy require extensive computational resources,which either require bulky and inefficient devices or require the sensor data to be processed on cloud ***,there is always the risk of privacy invasion,data misuse,and data manipulation when the raw images are transferred to cloud servers for processing facical emotion recognition(FER)*** possible solution to this problem is to minimize the movement of such ***:In this research,we propose an efficient implementation of a convolutional neural network(CNN)based algorithm for on-device FER on a low-power field programmable gate array(FPGA)*** is done by encoding the CNN weights to approximated signed digits,which reduces the number of partial sums to be computed for multiply-accumulate(MAC)*** is advantageous for portable devices that lack full-fledged ***:We applied our approximation method on MobileNet-v2 and ResNet18 models,which were pretrained with the FER2013 *** implementations and simulations reduce the FPGA resource requirement by at least 22%compared to models with integer weight,with negligible loss in classification ***:The outcome of this research will help in the development of secure and low-power systems for FER and other biomedical *** approximation methods used in this research can also be extended to other imagebasedbiomedicalresearchfields.

关键词： facial expression detection emotion recognition FPGA implementation convolutional neural network signed digit approximation

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Isolation and Characterization of Beneficial Microorganisms in Organic, Semi-Organic and Conventional Fertilizer Treated Agricultural Field Soil and Comparison of Bacterial Richness

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Journal of Agricultural Chemistry and Environment 2020年第4期9卷 223-239页

作者： md. Mahfujur Rahman Laisa Ahmed Lisa Sunzid Ahmed md. Nazim Uddin Tuhina Hasan Sharmin zaman Department of Microbiology Jagannath University Dhaka Bangladesh Department of Biochemistry and Molecular Biology Jagannath University Dhaka Bangladesh Centre for Advanced Research in Sciences (CARS) University of Dhaka Dhaka Bangladesh Horticulture Research Center Bangladesh Agriculture Research Institute (BARI) Gazipur Bangladesh

The effect of different farming systems on microbial communities in agricultural environment was investigated in the present study. Depending on the present farming trend, the microbial distribution in agricultural soils treated with organic, semi-organic and conventional fertilizers was analyzed. A total of 20 soil samples were collected from different types of agricultural fields of Bangladesh Agricultural Research Institute (BARI, Gazipur). Microorganisms playing beneficial roles in soil such as nitrogen fixation (e.g. Rhizobium sp., Azotobacter sp.), phosphate solubilization (e.g. Bacillus sp., Pseudomonas sp., Phosphobacteria) and auxin production (e.g. Pseudomonas sp., Serratia sp. and Bacillus sp.) were evaluated from each of the samples. The results revealed that agricultural fields treated with chemical fertilizers showed lower microbial count than that of organic fertilizer treated agricultural fields’ soil samples. In addition, organic fertilizers amended field soils have higher phytohormone (Auxin) activities, phosphate solubilization bacteria and other bacterial richness compared to chemical fertilizer applied field soil.

关键词： Chemical Fertilizer Organic Fertilizers Bacterial Richness and Bacterial Diversity

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Comparison between Tencel-Flax Blended Slub Yarn and Cotton-Flax Blended Slub Yarn

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Journal of Textile Science and Technology 2022年第4期8卷 221-230页

作者： Mohammad Nayemul Islam Lamia Latifun Rahman md. Imran Hosen Jaglul Hoque Mridha md. Sakib-Uz-zaman md. Shahin Hossen Nazmus Sakib Khan Department of Textile Engineering Sonargaon University Dhaka Bangladesh Department of Textile Engineering Primeasia University Dhaka Bangladesh Epyllion Limited Epyllion Group Dhaka Bangladesh Auxicolour Bangladesh Limited Dhaka Bangladesh

The blending of different fibers is done for the manufacturing of yarn to ensure the presence of multiple properties in the resultant yarn which is impossible if we use only one type of fiber. Tencel is regenerated cellulosic fiber & flax is natural bast fiber. Tencel shows more versatility than flax. Tencel has a softer feel with a variety of end uses. Tencel is wrinkle-prone and stiff. Tencel shows extreme strength even in wet conditions and at the same time, it is more durable than linen. The most important fact is that the heat dissipation property of flax is 5 times higher than wool & 19 times higher than silk. Linen clothing can lower the body temperature by 3 to 4 degree celsius in hot weather than clothing made of wool and silk. A yarn made of both Tencel & linen (50:50) will contain the properties of both fibers. At the same time, we can make this yarn more aesthetic by incorporating a slub. It was observed that the slub yarn made by blending Tencel and flax fiber shows better properties than the slub yarn of the same count made from the blending of cotton and flax.

关键词： Flax Tencel Slub Blending

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Pattern of Presentation of Iatrogenic Biliary Injury Following Laparoscopic Cholecystectomy

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Open Journal of Clinical Diagnostics 2022年第4期12卷 55-62页

作者： Fahmid-Uz-zaman Mohammad Aminul Islam md. Saba Al Galib md. Mashkurul Alam md. Shamsuddoha Khan Muhammad Tanvir Alam Akhanda Sania Hossain Laila Siddika Mohammad Emrul Hasan Khan Abul Bashar md. Jamal Department of Surgery Dhaka Medical College Hospital Dhaka Bangladesh Department of Surgery Shaheed M. Monsur Ali Medical College Hospital Shirajgonj Bangladesh Department of Pediatric Surgery Dhaka Medical College Hospital Dhaka Bangladesh Department of Surgery Shaheed Suhrawardy Medical College Hospital Dhaka Bangladesh National Institute of Cancer Research and Hospital Dhaka Bangladesh Department of Laboratory Medicine Sheikh Russel National Gastroliver Institute and Hospital Dhaka Bangladesh Mugda Medical College and Hospital Dhaka Bangladesh

Background: Cholecystectomy is one of the most now common abdominal surgeries performed every day. The incidence of bile duct injury (BDI) following open cholecystectomy is only 0.1% - 0.2%. After the introduction of laparoscopic cholecystectomy, the incidence has gone up to 0.4% - 0.7%. The present study is a prospective analysis of all patients with bile duct injury who were admitted to Dhaka Medical College Hospital during or at a variable period following cholecystectomy. Methods: To determine the pattern of presentation of iatrogenic biliary injury following cholecystectomy in the department of surgery of Dhaka Medical College Hospital, a total of 30 patients were purposively selected from May 2018 to November 2018. Patient particulars, records of physical and clinical evaluation, and operative details were collected by individual researchers. Data analysis was done by SPSS for windows version 21. Results: BDI was found very common among the age group 21 - 30 yrs (36%) and female dominant (60%). Majority of the patients presented with abdominal pain (96%), intra-abdominal collection (88%), biliary peritonitis (68%), cholangitis (60%), and obstructive jaundice (40%), and biliary fistula (40%). Laparoscopic cholecystectomy (84%) was the principal cause of biliary injury in our study. 48% of patients experienced clinical features within 7 days post-cholecystectomy. Per-operative diagnosis was done in only 12% of cases. 44% of patients in this study were recognized as Bismuth grade-3, followed by 36%, grade-2 patients. Management outcomes included wound infection (41.66%), minor bile leak (25%), peritonitis (8.33%), and renal impairment (8.33%). Conclusion: The effect of BDI is an extremely distressful clinical condition for the patients and their family members, hence proper care and management protocol should be followed.

关键词： Bile Duct Injury Laparoscopic Cholecystectomy Post-Operative Complications Bangladesh

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Consideration of Environmental Effect of Power Generation: Bangladesh Perspective

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Energy and Power Engineering 2013年第4期5卷 1521-1525页

作者： Iftekhar zaman Arnab Tausif Ali M. Shidujaman md. Mayen Hossain Dept. of Electrical and Electronic Engineering American International University-Bangladesh Dhaka Bangladesh

Nowadays for power generation, environment is a major consideration. The heart of power generation is power station. At present there are almost above 40(Both Government & Rental) power station in Bangladesh. Among these 80% of power station is gas based. Rest of the 20% is coal, liquid and furnace oil based. Bangladesh has only one Hydraulic power station. These gas and coal based power stations are giving adverse effect in Bangladesh. The main emissions from coal combustion at thermal power plants are carbon dioxide (CO), nitrogen oxides (NO), sulfur oxides (SO), chlorofluorocarbons (CFCs), and air- borne inorganic particles such as fly ash, soot, and other trace gas species. Carbon dioxide, methane, and chlorofluorocarbons are greenhouse gases. These emissions are considered to be responsible for heating up the atmosphere, producing a harmful global environment. It is known to all that hydro power station is a clean source of energy, but it has also some ecological and environmental effect. Dhaka is one of the top polluted city in the world. So for power generation if the environmental effect is not considered then Bangladesh will be in great trouble. The purpose of this paper is to discuss the present and future possible environmental effect of power generation in Bangladesh.

关键词： Environment Pollution Power Generation Air pollution Water Pollution Thermal Pollution Acid Rain Renewable Energy Nuclear Power Plant

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