KUET Institutional Repository (Khulna University of Engineering & Technology)
Not a member yet
1045 research outputs found
Sort by
Effect of Various Operating Parameters on Power Generation from Mediator Less Microbial Fuel Cell
No full textThis thesis is submitted to the Department of Energy Science and Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Engineering in the Department of Energy Science and Engineering, May 2019.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 59-68).Microbial fuel cell (MFC) is the most adaptable renewable energy technology for its
multidimensional applications. This bioreactor converts the chemical energy stored in
decomposable organic and inorganic compound into electricity with the help of bacteria. The
whole process occurred in an air free environment. Significant amount of research works has
been carried out to improve the yield of MFC. In this research work, three MFCs were
constructed using locally available materials. Local window glass was used to construct the body
of MFC, Agar-agar solution and bandage cloth were used for salt bridge. Several experiments
were performed in batch mode to investigate the effects of various operating parameters such as
electrode material, electrolyte source, pH and concentration. To investigate the effect of
electrode materials, three anode materials (carbon felt, Zinc and carbon rod) were used and
copper was used as cathode with every cathode. Zinc-copper combinations gave 28.2% higher
power than carbon felt-copper and 57.1% than carbon rod-copper. For operating pH, pH 6, pH 8
and pH 10 were investigated, where maximum power generated from pH 8, its value was
680.625 mW. To investigate better electrolytic source municipal waste water, river water
(Bhairab) and hospital waste water was studied and maximum power (5.907mW) generated from
Bhairab river water. Additives affect the power generation of microbial fuel cell; urine mixed
waste water generates 52.13% and 9.6% higher power than raw waste water and fish waste
mixed waste water respectively. 10% urine mixed electrolyte gives maximum voltage (1146 mV)
but top power obtained from 15% urine mixed waste water. To get better yield source of
electrolyte (Bhairab river water), electrode combinations (Zinc-copper), operating pH (pH 8) and
15% urine as additive can be used.Md. Abdul HalimMaster of Science in Engineering in the Department of Energy Science and Engineerin
A Cross-sectional Study of Work-Related Musculoskeletal Disorders among Construction Workers in Bangladesh
No full textThis thesis is submitted to the Department of Mechanical Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engineering, December 2019.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 54-58).The construction activities are closely associated with many occupational injuries. Work-related musculoskeletal disorders (WMSDs) are the most common occupational injuries faced by construction workers. WMSDs refer to a set of painful illnesses of human body muscles, tendons, nerves, ligaments, joints, etc. The construction workers also face injuries from the work site accidents. Most of the accident occurs in the construction site by falling objects on the worker’s body, workers fall from the height, electrocution, etc.. The workers feel pain in different body parts, sometimes become partial or permanent disable due to worksite accidents. There are many factors associated with the occupational injuries. Different researchers from different countries have studied the work-related musculoskeletal disorders of construction workers. As far, I know, no researchers have studied these types of disorders on Bangladeshi construction workers. Keeping this view in mind, the study investigated the work-related musculoskeletal disorders and accidental injuries among the Bangladeshi construction workers. This study also tried to find out the factors associated with Work-related musculoskeletal disorders (WMSDs). For this purpose, a cross-sectional study was conducted through a structured and Modified Nordic Questionnaire. The structured questionnaire contained the socio-demographic characteristics, the physical risk factors, environmental risk factors, and the equipment risk factors. The Modified-Standardized Nordic Questionnaire (MNDQ) is used to identify the musculoskeletal pains on different body parts over the previous year. All the questionnaires were two categories as an open-end and yes/no. In this study, a total of 450 (362 males and 88 females) construction workers aged between 18 to 65 years old were taken from the different construction sites at Jashore, Khulna and Satkhira, Bangladesh. Their main activities were mixing sand and cement, ironwork, lifting and carrying mortar, bricklaying, plastering, concrete laying and tiles fitting. The results found that overall 70.2% of workers reported that they had suffered at least one body part injury over the last 12 months. Among the nine body parts, lower back (49.80%) was the highest suffered body part and a thigh (9.60%) was the lowest suffered part. It is found the occurrences of work-related musculoskeletal disorders (WMSDs) were associated with socio-demographic characteristics such as gender, age, work experiences, working time, and working types. To minimize the work-related musculoskeletal disorders workers suggested to provide safety aid (26.70%), provide proper training and education (19.50%), to design hand tools in ergonomically (24.90%), ensuring good working environment (26.40%), and proper use of the personal protective equipment (21.80%). Most of the workers (32.20%) did not specify how to prevent work-related musculoskeletal disorders.
About 60.70% of the participant experienced with accidents during their work in the construction site. Most of the accidents occurred by the falling objects on the worker’s body (19.10%), workers fall from the height (25.30%), electrocution (3.30%) respectively. Based on the data most of the workers (29.80%) injured in different body regions due to the worksite accidents. The workers also identified the causes of accidents such as personal negligence, lack of work experience, improper use of PPE (Personal Protective Equipment), absence of a good working environment, the overload of work, and lack of safety facilities. Above allcauses, the lack of safety facilities (42.80%) reported as the highest reason behind the accidents. It is found from this study that the prevalence of work-related musculoskeletal
disorders and accidental injuries among the Bangladeshi construction workers are high. Finally, the author had made some recommendations for both workers and management of the construction sites.Md. Sumon RahmanMaster of Science in Mechanical Engineerin
Prediction on Ischemic Heart Disease using Machine Learning Approaches
No full textThis thesis is submitted to the Department of Biomedical Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Biomedical Engineering, October 2019.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 58-69).Ischemic heart disease (IHD) is a terrible experience that occurs when the flow of blood
severely reduced or cut off due to plaque deposited on the inner wall of arteries that brings
oxygen to the heart muscle, leads to the ischemic heart attack (IHA). Atherosclerosis i.e.
plaque deposition on the inner wall of arteries is a silent process, has no critical symptoms
to get a warning before IHD. For this reason, early detection is very important for the proper
management of patients prone to IHD. In this thesis work, it was tried to predict IHD on the
basis of patient history, symptoms and pathological findings of patients with heart disease
using computational intelligence. Total 506 patient’s data with a maximum of 151 features
including historic, symptomatic and pathologic findings were collected from AFC Fortis
Escort Heart Institute, Khulna, Bangladesh. First, it was tried to identify the significant risk
factors of IHD i.e. the features which are significantly correlated with IHD by applying
different feature selection techniques. Then IHD was predicted using significant risk factors
by applying different classifier algorithms. The significant risk factors of IHD were
determined by using Chi-Square correlation, Ranking the features based on information gain
and Best First Search techniques. Among 151 collected features only 28 features showed
high correlations with IHD based on 0.05 significance level and information gain 1% or
above. 10-fold cross-validation technique was applied with different classification
algorithms e.g. Artificial Neural Network (ANN), Bagging, Logistic Regression, and
Random Forest to predict IHD using the most significant 28 risk factors. IHD prediction
accuracy was observed ranges from 95.85% to 97.63% with different classifier algorithm.
Random Forest showed the best prediction performance with an accuracy of 97.63%. The
same processing technique and classification algorithms were applied to the Cleveland
hospital dataset to validate our prediction approach. The observed IHD prediction accuracy
was 80.46-83.77% without applying the proposed processing techniques, but the accuracy
degraded to 79.80-81.46% applying the proposed processing techniques. The Cleveland
hospital data contains 303 patients’ data with only 13 features whereas the collected dataset
contains 506 patient’s data with 28 nicely correlated IHD risk factors. This is why the
proposed method is not suitably applicable to Cleveland dataset.M. RaihanMaster of Science in Biomedical Engineerin
Study on Thermal and Mechanical Properties of 2D Silicon Carbide using Molecular Dynamics Simulation
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 Engineering in Electrical and Electronic Engineering, January 2019.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 64-70).Recently, two dimensional silicon carbide (2D-SiC) is expected to be a promising semiconductor
for nanoelectronics and nanoelectromechanical systems (NEMS) due its exceptional electronic,
thermal and mechanical properties. Although numerous studies have been performed on the
characterization of structural and electronic properties of 2D-SiC, the thermal and mechanical
behaviors have not been well studied. In this dissertation, non-equilibrium molecular dynamics
simulation has been performed to explore the thermal properties of 2D-SiC. Moreover, the
mechanical behaviors of 20-SiC are quantified using the virial stress based molecular dynamics
simulation.
This dissertation provides many new important findings based on these simulations such
as a slowly decreasing trend of thermal conductivity in the high temperature region, deviating the
-1/T law due to the influence of high frequency pbonons and Umklapp limited phonon
scattering. The simulated thermal conductivity of 2D-SiC using optimized tersoff potential is
found as -271.03 W/mK at a length of 600 run which is one order higher than silicene of the
same length. However, due to the lower acoustic group velocities, lower Debye temperature, and
additional phonon scattering effect of the binary SiC system, the reported thermal conductivity is
much lower than graphene. The phonon density of states (PDOS) shows a strengthening behavior
of the low frequency acoustic peaks with the increase of sheet length, quantifies the increasing
trend of thermal conductivity with length at room temperature. Above room temperature a
shrinking trend of acoustic phonon peaks is noticed, conveys the causes of decreasing trend of
thermal conductivity with temperature. However, due to the consideration of ground state
phonon modes in specific heat capacity, the quantum corrected thermal conductivity shows an
increasing trend up to Debye limit. In addition, it is found that the optimized tersoff potential
provides a better estimation of the thermal conductivity than the original tersoff potential due to
proper parameterization of the SiC system with analytical model.
Further, the mechanical behaviors of pristine and defected 2D-SiC have been studied.
The effect of point, bi, and mixed vacancy defects on the tensile strength and elastic modulus
have been determined. The estimated tensile strength and elastic modulus of pristine 2D-SiC
show a linear reduction trend with temperature due to the strong thermal variation effect. For
pristine 20-SiC, a tensile strength of 53.625±7 GPa with a failure strain of 0.153 is found at
room temperature. However, with the introduction of vacancy defects, the tensile strength and elastic modulus of 20-SiC reduces significantly due to the symmetry breakdown and the bond
breaking effect. Among the three types of vacancy, the point vacancy shows the most
treacherous effect on the tensile strength and elastic modulus due its greater bond breaking
effect. It is found that for 1 %-point vacancy, the tensile strength is reduced about 66.35% from
that of pristine case. Therefore, these findings are very much important to understand new
phonon transport physics and potentially lead to not only in nanoelectronics and nanoelectromechanical systems, but also in novel applications of 2D-SiC in various emerging
fields.Abu Syed Md. Jannatul IslamMaster of Science in Engineering in Electrical and Electronic Engineerin
Rehabilitation and Flexural Strengthening of Reinforced Concrete Beams using External Steel Reinforcement
No full textThis thesis is submitted to the Department of Civil Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering, January 2019.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 92-99).Rehabilitation of existing structures in the form of structural strengthening may be required due to decrease of load carrying capacity with aging, improper design or to accommodate with increased load requirements with time or codal change. Structural demolition can be reduced by applying strengthening technique to improve the capacity. This research investigated the flexural behavior of reinforced concrete (RC) beams rehabilitated with different strengthening techniques involving external steel reinforcement. The main focus of the study was to apply those strengthening techniques under service load condition. Twelve half-scaled beams were prepared and divided into six groups. The first group was used as control specimens while the other five groups were strengthened with different strengthening techniques. The control specimens were tested by 3rd point loading to find the ultimate load carrying capacity in flexure. Then all other beams from each of the five groups were preloaded with 65%-75% of the ultimate load to simulate the service load condition. Some initial cracks were formed in each beam due to preload before strengthening. After observation of the crack patterns, the preloading was released and the beams were ready for strengthening. Two groups were strengthened with 3mm thick external steel plate bonded with epoxy adhesive, of which the steel plate in one group was anchored by steel bolts in addition to the adhesive. Two different types of epoxy adhesive were used in two separate beams of each group. The 4th and 5th groups were strengthened with near surface mounted (NSM) external steel bars. The NSM bars in the 4th group were attached by epoxy adhesives while those in the 6th group were welded with the original bottom stirrups after removing the bottom concrete cover. The remaining group was strengthened by using external steel angle welded with the bottom stirrups after removal of the required concrete cover. Finally, the bottom concrete cover was cast again.
The average ultimate load carrying capacity of control beams in flexure was found to be 49.1kN. The ultimate capacity of strengthened beams with steel plate was observed to be 92.4kN for a specific adhesive type, which was as much as 88% higher than the control beams. The capacity was greatly influenced by the type of adhesives and the bond strength between steel plate and concrete. Anchoring the steel plate by steel bolts at both ends in addition to the epoxy adhesive further increased the capacity to 104% higher than the control beams and mode of failure switched from a brittle to a ductile nature. The capacity of beams strengthened with NSM bars varied from 101.9kN to 115.0kN depending on the type of the adhesives. Flexural failure occurred either by the separation of NSM steel bars by bond failure or by pure bending. The beams strengthened with external steel angles welded with bottom stirrups showed an ultimate flexural load capacity of 124.4kN and 116.8kN, which were 153% and 138% higher, respectively than the control beams. A ductile behavior was obtained when the welded connections in this type of strengthening did not fail. The ultimate capacity was 127.5kN and 134kN for the beams strengthened with external steel bars welded with bottom stirrups which were 160% and 173% higher than the control beams and 95% and 100% of their designed strength. The initial flexural failure pattern in the unstrengthened beams was transformed to an obvious shear failure pattern in that case. After normalizing the experimental results with respect to external steel ratio and grade, it could be concluded that the NSM method of flexural strengthening was more effective in comparison to the other methods. On the other hand, strengthening with external steel plate was more convenient and easier to apply although its capacity is slightly lower than the NSM method.Md. Omar Ali MondalMaster of Science in Civil Engineerin
Investigation into Narrower Slot of Dumbbell Shape Defected Ground Structure Under a Standard Microstrip T-Line
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 Masters of Science in Electrical and Electronic Engineering, January 2019.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 50-54).Electromagnetic Band Gap Structures (EBGSs) delivered a wide assortment of plan choices for specialists working in the territory of microwave and photonics. The spotlight is currently
towards on discovering genuine applications. Because of the unbelievable capability of EBGSs, there are enormous applications in which they can be utilized.
This thesis describes the planar EBG structures in the forms of conventional circular and rectangular EBGSs and dumbbell-shaped defected ground structures (DS-DGSs). Conventionally, the DS- DGS consists of two bigger slots and a narrower slot. Here the shape of narrower slot of dumbbell shape DGS has been focused. Modified EBGS in the form of changing the gap height of narrower slots of dumbbell-shaped DGS cells has been studied. These modified DGSs provide wide stopband properties. The DS-DGSs study has been carried out with the investigation into narrower slots and their properties. Some modified designs have been proposed such as; changing the height and width of the narrower slot of the dumbbell-shaped DGSs we have seen the performance. We have also increased the number of narrower slot to see the performance. The modified designs perform better than the conventional DGSs reported in the open literature. The proposed DGSs yield lowpass filter (LPF) properties with good passband and amazingly wide stopband.
In this thesis, uniform circular and rectangular with different filling factor (FF) and DS-DGS
with similar periodicity like circular or rectangular structure have investigated. Then for the
better performance, we have focused on narrower slot of the DS-DGSs. This research conveys the performance of filter at about 4 GHz cutoff frequency. These distributions remove the unwanted spurious transmission in the band rejection region. It is seen that in the dumbbell shape DGS the number of the narrower slot has a significant role to control the depth and width of the stopband. Besides, the optimized design is achieved by varying the height of the narrower slot. For two narrower slots, it provides the best performance. The optimized design has the size of the larger slot of 5.22×5.22 sq mm and the narrower slot is 0.78×0.75 sq mm. The proposed DSDGS with two narrower slots is suitable for lowpass filter implementation.
Finally, the insertion loss (IL) and return loss (RL) performances of different designs have been compared. It is seen that our modified designs provide improved performance and more
compactness in terms of return and insertion-loss bandwidths. The sufficient explanations have been provided to validate the total research works.Md. Amir HossainMasters of Science in Electrical and Electronic Engineerin
University Course Scheduling using Prominent Nature Inspired Techniques
No full textThis thesis is submitted to the Department of Computer Science and Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Computer Science and Engineering, April 2019.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 55-61).The University Course Scheduling Problem (UCSP) is a highly constrained real-world combinatorial optimization task. Solving UCSP means creating an optimal course schedule by assigning courses to specific rooms, instructors, students, and timeslots by taking into account the given constraints. Several studies have reported different metaheuristic approaches for solving UCSP including Genetic Algorithm (GA) and Harmony Search (HS) algorithm. Various Swarm Intelligence (SI) optimization methods have also been investigated for UCSP in recent times and a few Particle Swarm Optimization (PSO) based methods among them with different adaptations are shown to be effective. In this study, two novel PSO and Group Search Optimizer (GSO) based methods are investigated for solving highly constrained UCSP in which basic PSO and GSO operations are transformed to tackle combinatorial optimization task of UCSP and a few new operations are introduced to PSO and GSO to solve UCSP efficiently. In the proposed methods, swap sequence-based velocity and movement computation and its application are developed to transform individual particles and members in order to improve them. Selective search and forceful swap operation with repair mechanism are the additional new operations in the proposed methods for updating particles and members with calculated swap sequences. The proposed PSO with selective search (PSOSS) and GSO with selective search (GSOSS) methods have been tested on an instance of UCSP resembling the course structure of the Computer Science and Engineering Department of Khulna University of Engineering & Technology which has many hard and soft constraints. Experimental results revealed the effectiveness and the superiority of the proposed methods compared to other prominent metaheuristic methods (e.g., GA, HS).Sk. Imran HossainMaster of Science in Computer Science and Engineerin
