Human Gait Analysis is crucial in diagnosis, monitoring, treatment, and rehabilitation. It requires the measurement of gait parameters like joint angles, angular motion, ground reaction force (GRF), momentum, step width, step length,... more
Human Gait Analysis is crucial in diagnosis, monitoring, treatment, and rehabilitation. It requires the measurement of gait parameters like joint angles, angular motion, ground reaction force (GRF), momentum, step width, step length, velocity, etc. This study introduces a markerless, easy-to-use approach for measuring one of the gait parameters i.e., knee flexion/extension angle, and verifies it with an existing standard marker-based approach. Knee flexion/extension angle is calculated via Machine Learning (ML) pose estimation model “MediaPipe Pose” and Computer vision (CV) without the use of markers. For the verification of accuracy, the obtained values are compared with the data on each video frame obtained from Kinovea® which is a marker-based motion analysis software. A correlation of 0.941 was observed between the results from Kinovea® and MediaPipe Pose. Similarly, the mean absolute error of knee angles was 5.88 degrees. The research shows that knee flexion/extension angle can...
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Entangled by a web-like pattern of rivers and rivulets, Nepal’s energy sector currently is dominated by hydroelectricity which sustains a major portion of the country’s economy. But still, after more than a hundred years of its operation,... more
Entangled by a web-like pattern of rivers and rivulets, Nepal’s energy sector currently is dominated by hydroelectricity which sustains a major portion of the country’s economy. But still, after more than a hundred years of its operation, the sector’s dependence on imports is uncanny. This not only upsizes the project cost but also the time and human resources. The research, therefore, aims to aid the cause by examining the prospect of manufacturing runners using local industrial expertise in synchronization with available data and research. Here, the paper focuses on the sand casting of a 750KW Francis runner and the design of its parameters namely gating and feeding system to ensure directional solidification. Apart from the conventional procedure, the casting of the runner was proceeded as three separate parts: hub, shroud, and blade which were later welded together. The gate and riser placement for each of the parts was designed independently and analysed for any shrinkage poros...
Turbine having complex profiles has always been a challenge to the manufacturers. With possible errors while manufacturing and surface finishing, it is nearly impossible attaining the same profile of blades or buckets as suggested by the... more
Turbine having complex profiles has always been a challenge to the manufacturers. With possible errors while manufacturing and surface finishing, it is nearly impossible attaining the same profile of blades or buckets as suggested by the hydraulic design. Specifically in the case of Nepal the manufacturing of Francis turbine runners has been a challenge due to its complex profile and lack of state-of-the-art manufacturing facilities in the Nepalese metal manufacturing industries. Many attempts have been made in the past to manufacture these runners with the available resources. However, the developed turbines have been of smaller size and dimensions and the process used for fabrication have been limited to these small runners. So, for fabrication of the Francis turbine runners a new process has been developed. The process makes use of a rapid prototyping technique called additive manufacturing. The developed method has made the manufacturers easier to manufacture the runners of comp...
This study primarily focuses on the thermodynamic analysis of single stage vapor absorption refrigeration system using R134a – DMAC solution as the working fluid. Variations in the performance parameters of the system are studied against... more
This study primarily focuses on the thermodynamic analysis of single stage vapor absorption refrigeration system using R134a – DMAC solution as the working fluid. Variations in the performance parameters of the system are studied against various operating temperatures of generator and absorber. The result of this theoretical study show that coefficient of performance (COP) value can be improved by elevating generator temperature up to certain level and lowering absorber temperature. At such elevated generator temperature, value of circulation ratio (CR) is lowered. The scope of this study is limited to the system with 1kW evaporator capacity and effectiveness of solution heat exchanger (SHX) as 0.8. For the proposed condition of source and sink temperature 120 ° C and 40 ° C respectively the maximum value of COP was found to be 0.41 and corresponding CR value as
Undershot wheel, one of the oldest types of water-wheels, is a vertical water-wheel with a horizontal shaft which rotates by the continuous strike of water flowing underneath the wheel on its blades/paddles/buckets. Relatively simple and... more
Undershot wheel, one of the oldest types of water-wheels, is a vertical water-wheel with a horizontal shaft which rotates by the continuous strike of water flowing underneath the wheel on its blades/paddles/buckets. Relatively simple and inexpensive to fabricate, it has been used widely in the past to generate electricity or to obtain torque to run certain mechanisms. Conventional undershot wheels made of wood used to have flat paddles which are considered to be less efficient. For the sake of its further simplicity and efficiency, an undershot wheel has been designed using high-density polyethylene pipes which are comparatively inexpensive and more resistant to water being non-corrosive and non-decaying. Additionally, it’s easier to form curve-shaped blades from these pipes than from conventional wood materials, thus increasing the wheel’s efficiency. Similarly, considering its applications which range from production of small-scale electricity to irrigation, the wheel has been pre...
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The biomass contains stored energy from the sun and is a renewable source of energy. Fluidized bed combustion (FBC) is one of the most promising energy conversion options available today for the solution of crisis of rapid energy usage.... more
The biomass contains stored energy from the sun and is a renewable source of energy. Fluidized bed combustion (FBC) is one of the most promising energy conversion options available today for the solution of crisis of rapid energy usage. FBC combines the high efficiency combustion of low grade fuel e.g. rice husk, wood and other agricultural waste products. The rice husk/rice straw is one kind of renewable energy source which is abundant in agricultural country like Nepal. We have used modelling tools like Solid works for the design of a laboratory sized CFB boiler and the simulation software ANSYS FLUENT. We have carried out steady state combustion to verify the results. The main objective behind our study was the design of a CFB boiler for laboratory purposes. The methodology followed was based on literature survey, design of fuel hopper, combustion chamber and cyclone and finally using the scenario we created a simulation in ANSYS FLUENT. Finally, the parametric excel sheet was ma...
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Casting is one of the oldest manufacturing processes that has been in use since 3400 BC. Over the years, casting technology has evolved tremendously and is one of the most integral parts of ancient history as well as a modern society. The... more
Casting is one of the oldest manufacturing processes that has been in use since 3400 BC. Over the years, casting technology has evolved tremendously and is one of the most integral parts of ancient history as well as a modern society. The world produced a total of 109.8 million tons of casting in the year 2017, which is a clear indicator of the massive capacity of this industry. Most of it in the current scenario is being used by the automotive industries. Despite being the biggest and the richest industry in the field of energy, hydropower has never been a major market for the casting industry. This might be because the hydropower components are mostly manufactured using other techniques such as machining and rolling. Nevertheless, studies have proven that casting can be used for the manufacturing of several components of the hydropower, especially hydro turbines. Casting technology comes with its own sets of advantages and limitations. This study presents an overview of the status...
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Additive manufacturing (AM) or 3D printing is a digital manufacturing process and offers virtually limitless opportunities to develop structures/objects by tailoring material composition, processing conditions, and geometry technically at... more
Additive manufacturing (AM) or 3D printing is a digital manufacturing process and offers virtually limitless opportunities to develop structures/objects by tailoring material composition, processing conditions, and geometry technically at every point in an object. In this review, we present three different early adopted, however, widely used, polymer-based 3D printing processes; fused deposition modelling (FDM), selective laser sintering (SLS), and stereolithography (SLA) to create polymeric parts. The main aim of this review is to offer a comparative overview by correlating polymer material-process-properties for three different 3D printing techniques. Moreover, the advanced material-process requirements towards 4D printing via these print methods taking an example of magneto-active polymers is covered. Overall, this review highlights different aspects of these printing methods and serves as a guide to select a suitable print material and 3D print technique for the targeted polymer...
Research Interests: Polymers()
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This research deals with the design and analysis of the nozzle and bed materials required for fluidized bed boiler. The design parameters (Diameter of the bed particle, Range of the terminal velocities, Minimum Fluidization /Bubbling... more
This research deals with the design and analysis of the nozzle and bed materials required for fluidized bed boiler. The design parameters (Diameter of the bed particle, Range of the terminal velocities, Minimum Fluidization /Bubbling velocities, Maximum amplitude and steady velocities) were calculated using Microsoft Excel by interpreting and solving various formulas. Best bed material was selected on the basis of their various characteristics like porosity, adhesive or cohesive properties, resistance to flow etc. An important characteristic change of air distributor velocity with combustion chamber temperature has been established. ANSYS was used as a simulation tool for the analysis. Static Structural solver was used to carry out the strength analysis of the designed wind box. Likewise, computational fluid dynamics (CFD) was carried out using FLUENT solver. Air flow inside the wind box and fluidization phenomena was verified using FLUENT. Furthermore, the designed system was checked for its validity by comparing the results from the Excel sheets and theoretical calculations with simulation results. Lastly, correlation between temperature and velocity inside combustion temperature were determined to identify their relationship with each other.