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Prototype Development of a Joint Padded Metatarsal Cup to Enhance Female Foot Musculoskeletal Safety
No full textThis thesis is submitted to the Department of Industrial Engineering and Management, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Engineering in Industrial Engineering and Management, December 2019.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 44-49).This study investigated the feasibility of joint padded metatarsal cup on plantar pressures
and stress distribution in the bone alignment of female foot with high heeled footwear
during balanced standing. The aim of this study is to redistribute the plantar pressure away
from the medial side of the forefoot. A joint padded metatarsal cup was developed from
medium soft ethylene vinyl acetate (EV A) and very soft ethylene propylene diene
monomer (EPDM) neoprene sponge. The participants of three categories were selected for
the study. The peak plantar pressure and a radiographic assessment of foot
musculoskeletal alignment were carried out. The results showed that the magnitude of load
on medial forefoot area could be effectively reduced by inserting joint of soft materials on
metatarsal region. Hence load on hallux could also be reduced satisfactorily which could
resist the hallux valgus deformity. A comparison of conventional system and jointing
materials separately with the developed prototype was made and found that the developed
prototype of joint padded metatarsal cup (JPMC) provides more relaxation of plantar
pressure and musculoskeletal safety and confirms more comfort on hypothesis test. The
concept of joint padded metatarsal base should therefore be considered to help in
designing musculoskeletal safety footwear.Abu JorMaster of Science in Engineering in Industrial Engineering and Managemen
Study on Sensitivity of Microphysics for the Simulation of Rainfall for the Month of May 2015 over Bangladesh using High Resolution WRF
No full textThis thesis is submitted to the Department of Physics, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Physics, March 2019.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 79-84).In the present study, the Advanced Research WRF (ARW) model v3.8.1 has been used to simulate the rainfall for the month of May 2015 all over Bangladesh. The initial and boundary conditions are drawn from the global operational analysis and forecast products of
National Center for Environmental Prediction (NCEP-FNL) available at 1˚×1˚ resolution. The model was configured in nested domain with 18 and 6 km horizontal grid spacing with 100 × 96 and 103 × 127 grids respectively in the east-west north-south directions with 30 vertical levels. Time step of integration is set to 90 and 30 seconds for maintaining computational stability as the model uses third-order Runge-Kutta time integration scheme. In this research, six different microphysics schemes such as Lin et al., WSM6, Thomson, Morrison Double-Moment (M-2M), Stony Brook University (SBU), and WDM6 coupling with Kain-Fritsch (KF) cumulus parameterization scheme has been used to simulate the monthly total rainfall, monthly heavy rainfall, monthly rainy days and monthly heavy rainy days for the month of May 2015 all over Bangladesh. The outputs obtained by using different
microphysics are compared with the observed outputs at 33 meteorological stations of BMD
and Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) output. Standard deviation of all observed, PERSIANN and model
simulated parameters have been analyzed and compared.
The maximum monthly observed rain of May 2015 at Sylhet is 752 mm but WSM6, M-2M and WDM6 schemes have simulated 831, 788 and 742 mm for day 1 prediction; WSM6, WDM6 and SBU-Lin schemes have simulated 757, 916 and 981 mm for day 2 prediction and
WSM6 and WDM6 schemes have simulated 741 and 925 mm for day 3 prediction, respectively and all other MPs have simulated much higher rainfall at domain (D1). The WDM6, M-2M and Lin et al. schemes have simulated 744, 807 and 923 mm for day 1 prediction, WSM6 and WDM6 schemes are 714 and 877 mm for day 2 predictions and WSM6, SBU-Lin and Lin et al. schemes are 802 and 913 and 998 mm, respectively for day 3
prediction at domain (D2). WDM6 scheme gives the better performance of rainfall and rainy
days all over the country.Md. Salman KhanMaster of Science in Physic
Multi-Mask Based Stabilization of Turbulence Degraded Videos Containing Moving Objects
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, November 2019.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 54-56).Stabilizing videos and detecting moving objects are important tasks in many computer vision applications through it becomes challenging because of the presence of atmospheric turbulence that causes random pixel shifting and blurring of the videos. Because of random change in magnitude and direction of hot air and winds present in the atmosphere, the refractive index of the medium changes nonuniformly. This cause deformation of pixels and makes the tracking system confused while detecting moving objects. This effect becomes more severe with the increase of imaging distance. This thesis proposes an improved method for correcting geometrical distortions of videos degraded by atmospheric turbulence while keeping moving objects unaltered. In this method, by taking the median of input frames, the background frame is estimated and three different techniques are used to generate three different masks. Then, by combining all three masks, a more accurate mask is generated. This refined mask is employed to properly detect the moving objects, and finally combining with the background a stabilized video output is obtained. Performance of this method is tested by applying it on different real-world datasets. A comparison with an existing method shows that the proposed method gives better moving objects detection and improved stabilization of distorted videos.Bhabesh RayMaster of Science in Electrical and Electronic Engineerin
Flow Characteristics and Environmental Flow Requirement of Gorai River in Bangladesh
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, July 2019.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 82-84).Environmental flow requirement certifies natural condition prominence of a river. Due to terrestrial location, rivers in Bangladesh have faces precise high flow in wet season and low flow in dry season. Since the current condition of a river flow characteristics has proven on historic flow data, so estimation of environmental flow requirements for the rivers are censoriously important for Bangladesh. The purpose of the research is to assess environmental flow requirement of Gorai River and to evaluate flow characteristics of the river through the comparison between past and recent time. Two stations are selected to assess the environmental flow circumstance for Gorai River system. The selected stations are Gorai Railway Bridge and Kamarkhali Transit station. There are several methods for calculating the environmental flow requirements of a river system. Three popular methods are used here for estimation of the environmental flow on the selected stations. The three methods are Mean Annual Flow (MAF) method, Flow Duration Curve (FDC) method and Constant Yield (CY) method. These methods are appropriate for hydrological attitude and in use of chronological flow data.
Daily discharge data of selected stations recorded by Bangladesh Water Development Board (BWDB) has been collected and analyzed for two periods i.e. G1 period (for the year 1984 to 1999) and G2 period (for the year 2000 to 2016), and IHA software (version 7.1) has been exercised. The analysis has been done according to MAF, FDC and CY methods. It is observed from the analysis that, the Mean annual flow of Gorai Railway bridge station is 1012 Cumec during 1984 to 2016, and Mean annual flow of Kamarkhali transit station is 795.1 Cumec during 1984 to 2016. As low flow season is the main concern, about 202.4 Cumec flow is required to maintain good condition for Gorai Railway bridge station and 159 Cumec flow is required for Kamarkhali transit station in MAF method. The relationship between the magnitude and duration of stream flows is presented by flow duration curve (FDC). FDCs are used mainly to set environmental flow purposes. Flow duration intervals are stated as percentage of exceedance, with zero corresponding to the highest stream discharge in the record (i.e. flood conditions) and 100 to the lowest (i.e. drought conditions). As low flow season is the main concern, the environmental flow requirement based on FDC in LFS is found as 290 Cumec for Gorai Railway bridge station and 167 Cumec flow is required for Kamarkhali transit station in FDC method. During the low flow season the minimum requirement based on FDC method is retained during both intermediate and high flow seasons but not for low flow season which is the main concern. Environmental flow considering CY method for Gorai Railway bridge station is found as 221.4 Cumec and for Kamarkhali transit station it is found as 162.85 Cumec. The flow found in CY method is close enough to environmental flow requirement obtained from MAF and FDC methods.
It is found that the estimated environmental flows of Gorai River at Gorai Railway Bridge station are 202.4 Cumec, 290 Cumec and 221.4 Cumec for MAF, FDC & CY method, respectively. By averaging these values, the environmental flow is estimated as 237.93 Cumec. In the Kamarkhali transit station of Gorai River the environmental flows are estimated as 159 Cumec, 167 Cumec and 162.85 Cumec for MAF, FDC & CY method, respectively. Thus the average value of environmental flow is estimated as 162.95 Cumec. It shows that insufficient flow condition remains from December to May in both of the stations according to the estimated environmental flow requirement. August and March are the highest and lowest flowing months respectively for both of the stations.
It is observed that, the river condition is good at the high flow season but when the flow comes in low flow season it becomes lower than the environmental flows required for good habitat quality. The flows in the month of January to May are less than the EFR required. The flows of these months are less than the severe degradation flow. It shows severe problems for both the stations. For the Gorai river, it is necessary to maintain the flow values more than the severe degradation throughout the year to sustain the habitat quality for the river. The three methods show different values for environmental flow requirement. The flow requirements in the low flow season for three methods are found lower than the required flow in both stations. It shows that the river is endangered for habitat quality in low flow seasons. In every method it proved that, the Gorai River has flow scarcity because of the low flows from upstream.
The chloride concentration is generally found higher in the month of November to June. These are the low flow season that includes post-monsoon and pre-monsoon period. It shows a higher value of chloride concentration. The highest individual one day chloride concentration is found as 511 ppm, and the average monthly highest chloride concentration is found as 152.8 ppm in the month of February. At high flow season the flows are higher in the month of July to October. It shows a lower value of chloride concentration. The lowest individual one day chloride concentration is found as 20 ppm, and the average monthly lowest chloride concentration is found as 37.5 ppm in the month of October. The chloride concentration at low tide and high tide shows no significant difference for the same day.
The chloride concentration in high flow season is not much less than the concentration of the low flow season for the exceedance 0% to 30%. For the exceedance probability 30% to 100%, it shows a big difference of chloride concentration among the seasons. The salinity for less than 100 Cumec discharge is higher and the salinity decreases with increase in the fresh water discharge up to 500 Cumec. The salinity shows lower value with high discharge upto 60% of probability of exceedance. After that from 60% to 100% probability of exceedance freshwater discharge value did not shows significant effect on salinity change. Small increase in fresh water discharge cause large change in salinity concentration from 5% to 60% probability of exceedance.
The environmental flow highlights the basic need of a river to sustain the assortment of natural status of hydrologic systems in order to defend native biodiversity. Indicators are anticipated to assess the complete ecological health of the river and the degree of hydrologic alteration triggered by a particular functioning policy. The condition of a river systems eventually rest on environmental flow constituents, which may change seasonally.Md. Hasibul HasanMaster of Science in Civil Engineerin
Finite-State Predictive Current Control of a Simplified Three-Level Neutral-Point Clamped Inverter
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, November 2019.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 66-72).Multilevel inverter is one of the most important parts in renewable energy based power generating section as well as in motor drive applications. The quality of an inverter system depends on current total harmonic distortion (THD), switching loss, fault tolerant ability, dynamic responses, voltage stress, common mode voltage etc. Multilevel inverter yields low current THD, less voltage stress across the semiconductor switches and low switching frequency and thus less switching loss. However, using more number of semiconductor devices and neutral point voltage variation are the common problems for a neutral point clamped inverter. This is why different topologies of multilevel inverter are available in the literature in order to solve the aforementioned problems. The control scheme of a multilevel inverter also plays an important role to guarantee system’s performance. Recently, model predictive control (MPC) draws much attention to the researchers for its intuitive features and easy handling of nonlinearities of a system. The controller uses system model to predict the future behavior of the system over a prediction horizon. The control objectives are met by minimizing a predefined cost function that represents the expected behavior of the system. The objective of the proposed research work is to control the output load current of a three level simplified NPC (3L-SNPC) inverter topology using MPC. The simplified NPC inverter is considered, because less number of semiconductor devices used in the topology, even though further investigation is required on different factors such as voltage stress, common mode voltage, losses and switching frequency. MPC is used as controller because it can handle the dc link capacitors voltages balancing problem in a very intuitive way. Moreover, the average switching frequency reduction and over current protection can be easily implemented. Simulation results show that the proposed 3L-SNPC yields similar current THD, transient and steady state responses, voltage stress on the switches at the load side and over current protection capability as the conventional diode clamped based NPC inverter system. The two dc-link capacitor voltages are balanced properly with a neutral point voltage variation of close to zero. However, in comparison with the conventional NPC inverter, the proposed system is 15.25% computationally expensive which yields long execution time and thus less sampling frequency. In this study, two simplified MPC strategies are proposed for the 3L-SNPC inverter system in order to reduce the computational burden: single voltage vector prediction based MPC and selective voltage vector prediction based MPC. Both simplified strategies yield similar performance as the conventional MPC. The required execution times for the simplified MPC strategies are tested on hardware dSPACE 1104 platform. It is found that the single voltage vector prediction based MPC and the selective voltage vector prediction based MPC are computationally efficient by 8.28% and 62.9%, respectively, in comparison with the conventional MPC strategy. However, the average switching frequency and the overall loss in the proposed 3L-SNPC inverter are higher by 83.33% and 46.3%, respectively, than the conventional NPC inverter for a specified load current.Md. TariquzzamanMaster of Science in Electrical and Electronic Engineerin