http://dspace.mist.ac.bd:8080/xmlui/handle/123456789/66 2026-04-22T13:28:57Z http://dspace.mist.ac.bd:8080/xmlui/handle/123456789/1041 DEVELOPMENT OF A DIVER PROPULSION VEHICLE SIMULATOR FOR SEARCH AND RESCUE OPERATION NAZMUL HAQ, MOHAMMED Diver Propulsion Vehicle (DPV) is a self-propelled device used to facilitate divers to move freely underwater for search and rescue operations as well as for exploration purposes. DPV provides speed and a long-range to cover a wide area for various diving operations. A DPV generally consists of a pressure-resistant waterproof casing with a battery-powered electric motor that drives the propeller. It is widely used across the globe very effectively with a varying range of design and endurance capabilities. The design and fabrication of DPVs have been done in many developed countries. Indigenous design and fabrication of DPV are possible by utilizing local resources of Bangladesh. Designed prototype DPV is developed using SolidWorks, and a CFD analysis is carried out using Ansys software. After that, a DPV model is fabricated using resources from the local market. This project preliminarily focused on design, fabrication of DPV and simulated various parameters to get better results. Finally, the test and trial results and performance of the DPV are evaluated so that it can be used effectively for search and rescue operations in Bangladesh. Development of A Diver Propulsion Vehicle Simulator for Search and Rescue Operation 2023-06-01T00:00:00Z http://dspace.mist.ac.bd:8080/xmlui/handle/123456789/820 FABRICATION AND PERFORMANCE EVALUATION OF LOW COST HIGH IMPACT RESISTANT COMPOSITE RAHMAN, MD. ANISUR In this thesis low cost composite laminates were fabricated and their effectiveness against high impact was assessed. Glass fiber was used as the fiber and epoxy resin as the binder to create composite laminates. For enhanced binding properties, hardener and 6% cobalt were additionally included with the binder. The laminates vary in terms of layer count, glass fiber type (woven or matt), and curing time. For better comparison between same type of laminates, a few more variables, including the percentage of hardener, the quantity of matrix, and the curing time, were held constant. The mechanical properties were measured giving the Impact test more importance. The mechanical property tests such as the tensile test, compression test, bending test, Charpy impact test, Izod test, and free fall impact tests were done according to the different standardized test method. A laminate with greater performance was found after comparing all the attributes. The production costs were successfully reduced by the thesis because all the materials were readily available and locally manufactured with simple setups. The thesis successfully suggested a possible low-cost production setup for high impact resistant materials. The author firstly thanks Almighty Allah for His relentless blessings to complete this thesis work. The author would like to thank Professor Dr. Afsar Ali, who oversaw his thesis, for his advice, support, and assistance with this study work. The author would like to thank his co-supervisor, Prof. Dr. Enamul Hoque, for his consistent oversight, passionate observations, and direction throughout the thesis. The department's Dean, Brig Gen Md Humayun Kabir Bhuiyan, psc, whose guidance and support allowed the author to labor tirelessly and introduce new ideas, is also noteworthy. The author would also like to recognize the efforts of the lab staff, in particular Sub Asst Engr Mr. Md. Raju Ahmed and Sub Asst Engr Mr. Dibakar Tarafdar, who assisted with the setup and execution of experiments for the research work. Last but not the least, the author would like to express his utmost gratitude to his family members who has been patient and supportive all through this journey. 2023-03-01T00:00:00Z http://dspace.mist.ac.bd:8080/xmlui/handle/123456789/790 ANALYSIS OF MAGNETIC FIELD EFFECT ON PULSATING BLOOD FLOW IN ARTERIES OISHE, SADIA NOON Cardiovascular diseases including strokes, heart attacks, Stenosis, and atherosclerosis are considered the leading cause of death over the globe. The aorta, coronary, carotid, and femoral arteries are the most commonly impacted arteries. It's a crucial field of study for blood flow behavior. For many years, researchers have experimented with various numerical strategies to entice clinicians to trust their colorful contours. In recent, the impact of magnetic fields on blood flow is one of the developing approaches to treating different types of diseases. However, the efficiency of MHD capture is still unclear, and there is less systematic strategy to understand the flow behavior of blood. In this study, a simulationbased three-dimensional human aorta (brachiocephalic trunk, left subclavian, and left carotid) with transient conditions is analyzed to predict changes in blood flow distribution and flow patterns under with and without magnetic field conditions. Blood is modeled as non-Newtonian fluids along with plasma. VOF modeling for multiphase flow is used to mix RBC and plasma to predict the pulsating condition for the flow. Moreover, 1 Tesla magnetic field is applied to the selected section of the aorta. For simulation purposes, ANSYS Fluent software is used to identify the values for velocity, pressure, and wall shear force to understand the flow behavior of blood. The result shows that velocity, pressure, and wall shear stress are affected by exposure to MHD. By applying MHD, due to the freezing effect, the flow velocity slows down by about .035% while pressure increases by 9%, wall shear stress increases by 1.46% as well as mass flow. All praise be to Allah, the Cherisher and Sustainer of the worlds for His kindness and blessings for allowing me to do this colossal work and finally materialize it. The author expresses her deepest gratitude and profound indebtedness to her supervisor, Professor Dr. Dipak Kanti Das, Department of Mechanical Engineering, MIST, Dhaka, for his continuous supervision, valuable opinions, and motivation for research work all through the time. His regular support and direction made this research work possible and fruitful at every stage. The author is also thankful to Brig Gen Md Humayun Kabir Bhuiyan, psc, Dean, Department of Mechanical Engineering, MIST for his encouragement throughout the whole course. Special gratitude to Brig Gen Md. Omar Faruque, afwc, psc, Head, Department of Mechanical Engineering, MIST for his guidance at every step is duly acknowledged. The author would also like to thank Professor Dr. R. G. M Hasan for supporting me academically and personally and Professor Dr. A.B.M. Toufique Hasan for his valuable guidance and thanks to all Department of Mechanical Engineering, MIST for their cooperation in the successful fulfillment of the work. Finally, the author would like to express sincere thanks to all the beautiful people who stayed beside them when truly needed their support for the successful completion of this work. 2022-04-01T00:00:00Z http://dspace.mist.ac.bd:8080/xmlui/handle/123456789/664 Numerical and Experimental Investigation of Non-Circular Free Jet with and without Peripheral Twist for Improvement in Mass Entrainment, Mixing and Turbulence Characteristics Rahman Evan, Md.Touhidur Free jet flow is a basic flow configuration found in wide range of applications, majority of them being mixing, heating or cooling. The present study is therefore focused to improve the performance of the free turbulent jets within its ‘developing zone’ using two different mechanisms viz. (a) use of non-circular cross section jet and (b) introduction of swirl to jet by means of peripheral twist. The present research considers experimental and computational study of circular and non-circular turbulent jets (having Reynolds number 7.2 ×104 based on jet exit diameter). A ‘jet modifier pipe’, is used for the creation of circular and non-circular jets. Essentially, jet modifier pipe is small pipe through which circular jet is gradually changed to non-circular jet. Axial center line velocity, jet spread rate, potential core length and jet velocity profiles at various downstream locations are measured both experimentally and computationally. Turbulence intensity and tangential velocities at different downstream locations of the jet are determined numerically. The comparison of local jet velocity along jet axis indicates that the deceleration of axial velocity for triangular jet is maximum while that for circular jet is minimum which is indicating maximum potential core length for circular jet. A consistent observation is also showcased by jets wherein, the potential core length for circular jet is maximum, while non-circular jets show lower core length. The peak turbulence intensity location is found closer to jet exit for triangular and rectangular jets which is an indicator of efficient mixing. Rectangular jets show saddle shape profile at downstream of the pipe exit. The rectangular jet possesses an upper hand in terms of jet performance characteristics from the point of mixing characteristics. In order to improve the mixing characteristics of non-circular jets, a peripheral twist has been provided to jet modifier pipe. The parametric analysis included study of twist rate and length of jet modifier pipe. The study indicates that, increase in twist rate of jet modifier pipe increases tangential velocity of jet, with rectangular jet outperforming square and triangular jets. The twisted jet modifier pipe length has an opposite effect wherein, the smaller the length of pipe, the higher is the tangential velocity. In nut shell the computational and experimental studies indicate that the peripheral twist introduced to non-circular free jets are far superior to the circular free jet in the mixing process. 2018-12-01T00:00:00Z