Mechanical Engineering Commons^™

Experimental Investigation Of Spray Cooling Integrated With A Modified Vapor Compression Refrigeration System Using Several Refrigerants, Nabeel Mukhlif Abdulrazzaq

Theses and Dissertations

Spray cooling has gained increasing interest over the last three decades due to its high thermal performance as a direct cooling technique. Researchers are investigating spray cooling in thermal management systems for electronic applications, particularly focusing on the use of dielectric fluids including FC-72, FC-87, ammonia, and refrigerants such as R113 and R134a. Their studies indicate that the usage of dielectric fluids as a working fluid in spray cooling systems is promising and has significant thermal performance enhancement, which is suitable for a wide range of electronic applications. However, several deficiencies have been identified with the working fluids studied thus …

Nano-Engineered High-Performance Copper-Water Heat Pipes, Ahmed A. Abdulshaheed

Theses and Dissertations

Recently, heat pipes have gained an exceptional reputation as passive systems. They have become an attractive choice for many engineering applications due to their simple design, high rate of heat transfer, low weight, and low cost of maintenance [1]. A Heat pipe consists of a vacuumed shell filled partially with a compatible working fluid. Three main sections comprise a heat pipe: evaporator, adiabatic, and condenser section. The heat pipe utilizes the principle of evaporation and condensation for operations, i.e., the phase change of working fluid. Heat pipe allows high heat rates to transfer over considerable lengths with minimum temperature differences …

In-Service Performance Evaluation And Installation Recommendations For Cable Median Barriers On Non-Continuously Shielded, Divided-Median Kansas Freeways, Nathan Dowler

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The Kansas Department of Transportation (KDOT) installed 7.95 miles of cable median barrier (CMB) along K-10, K-96, and US-75 freeways in 2011 and 2012. In January 2020, KDOT funded a study to determine the in-service performance of its CMBs. In addition, KDOT sought to determine if it was cost-effective to modify guidelines for installing median barriers, which were based on annual daily traffic and median width.

Researchers reviewed every crash within approximately ¼ mile of a CMB installation and extracted crashes which involved a CMB impact. Researchers analyzed the critical details of each CMB crash, with particular emphasis on penetrations, …

Thermal Evaluation Of Advanced Leading Edge For Rotating Gas Turbine Blade: Numerical And Experimental Investigations, Amin Safi

Dissertations

Gas turbine engines play a vital role in our life. Our power demand is significantly and continuously growing. One approach to improve thermal efficiency in gas turbine engines requires a higher turbine inlet gas temperature. Advanced gas turbine engines operate at high temperatures, around 2000 K. Since operating at high temperatures may compromise the blade structure integrity, different cooling systems are used in a turbine blades. One of the most efficient cooling techniques is impingement cooling, mostly used in the leading edge. The leading edge experiences the highest temperature in the blade exposed to the hottest gas.

Researchers studied different …

In Situ Tem Characterization Of Microstructure Evolution And Mechanical Behavior Of The 3d-Printed Inconel 718 Exposed To High Temperature, Supriya Koul, Le Zhou, Omar Ahmed, Yongho Sohn, Tengfei Jiang, Akihiro Kushima

Mechanical Engineering Faculty Research and Publications

This in situ transmission electron microscopy work presents a nanoscale characterization of the microstructural evolution in 3D-printed Inconel 718 (IN718) while exposed to elevated temperature and an associated change in the mechanical property under tensile loading. Here, we utilized a specially designed specimen shape that enables tensile testing of nano-sized thin films without off-plane deformations. Additionally, it allows a seamless transition from the in situ heating to tensile experiment using the same specimen, which enables a direct correlation of the microstructure and the mechanical property of the sample. The method was successfully used to observe the residual stress relaxation and …

Composition-Dependent Solidification Cracking Of Aluminum-Silicon Alloys During Laser Powder Bed Fusion, Holden Hyer, Le Zhou, Abhishek Mehta, Sharon Park, Thinh Huynh, Shutao Song, Yuanli Bai, Kyu Cho, Brandon Mcwilliams, Yongho Sohn

Mechanical Engineering Faculty Research and Publications

Consistent manufacturing of volumetrically dense engineering components, free of solidification cracks by laser powder bed fusion (LPBF), has been demonstrated for Al-Si alloys such as AlSi10Mg and Al12Si. The success in LPBF of these alloys is attributed to the near eutectic composition with a small freezing range. To illuminate this observation, cracking susceptibility was examined from Scheil-Gulliver solidification modeling by calculating the hot cracking susceptibility, |dT/df_S^1/2|. To validate the findings from hot cracking susceptibility calculations, six binary Al-Si alloys, whose compositions were strategically chosen at hypo-, near-, and hyper-eutectic compositions, were gas atomized into alloy powders, and …

Electric Hydrofoil Board, Zach Flood, Nick Potter, Wesley Sava, Trent Walker

Mechanical Engineering Senior Theses

The electric hydrofoil community has become very popular in recent years with its two major subsections being divided up into those that buy their boards commercially and those that build their own (the DIY community). The commercial boards are extremely expensive and can reach prices of over $12,000. This is the root cause of the rapidly growing DIY community who can build functioning boards for around $3000. Reducing this entry cost has made the sport much more accessible to new members and has allowed both the size of the community and awareness of the sport to increase. For this report …

Elastic Tail Propulsion At Low Re, Rafaela Barreto, Jennifer Miranti, Yoel Park, Elijah Vidal

Mechanical Engineering Senior Theses

The use of microswimmers, or microscopic swimming robots, in the medical field is becoming more sought after for applications such as targeted drug delivery and microsurgery. While such microswimmers do not yet exist for use on patients, many researchers are working on this front to make them a reality. One of the main challenges in making these microswimmers a reality is creating propulsion in a low Reynolds number environment. This project aims to create and test a prototype of a swimmer which employs 3D circular movement of its tail for propulsion in a very viscous fluid, mimicking a low Reynolds …

Portable Bicycle-Powered Refridgeration, David Gilbert, Zach Gotvald, Kerri-Ann Kamei, Lindsay Mcconville, Brooke Watson, Brian Woo-Shem

Mechanical Engineering Senior Theses

Lack of access to viable, life-saving vaccines is a major public health problem worldwide. Our project objective is to create a feasible, frugal, and environmentally conscious transportation solution for vaccines. Our design for a bicycle-powered refrigeration system can function in both urban environments and rural areas with unreliable electricity and minimal infrastructure. This is enabled by integrating power generation from bicycle kinetic energy, thermoelectric cooling, voltage regulation, temperature control, and heat dissipation subsystems. The system is enclosed in solid housing to protect fragile vials against bumps and crashes and can be adapted to fit onto existing bicycle racks.

Project Shearwater Ground Effect Uav, Duncan Clark, Justin Cole, Zachary Karat, Aidan Nickels, Cole Wolfe

Interdisciplinary Design Senior Theses

The Shearwater unmanned aerial vehicle is a maritime fixed-wing drone that is designed to use ground effect force generated between the aircraft and a body of water to efficiently propel itself near the surface of a body of water. Shearwater features a virtual reality pilot interface and will act as a hybrid underwater vehicle that will eventually be able to operate both above and beneath the ocean’s surface. The Shearwater team developed existing design work to produce major subsystems that culminated in a flyable functioning prototype. An existing airframe was updated with working control surfaces tested in simulation and in …

Mobile Nanogrid, Daniel Mendoza, Ben Mahony, Charles Ju, Michael Batshon

Interdisciplinary Design Senior Theses

The mobile nanogrid is a standalone mobile power solution which uses a combination of automatic and manual tracking mechanisms to maintain a solar panel's perpendicularity to the sun over the course of the day in order to maximize energy generation. The power can then be consumed by a user or stored. It is designed to be placed on the roof of a vehicle for the recreational camping market to meet the need for mobile power generation. A scaled-down functional prototype was designed in SolidWorks, modeled in MATLAB Simulink, fabricated in the machine shop using a combination of off-the-shelf and custom …

Marine Robot Deployment And Control System, Nicky Castillo, Nick Ellis, Trent Kelsall, Matt Kiyama

Interdisciplinary Design Senior Theses

A full operations package for underwater research, including the mid-sized ROV Nautilus with a distributed control system, a topside graphical user interface (GUI), and a dedicated launch and recovery system (LARS), was developed to increase the operational efficiency of scientific exploration and experimentation missions through Santa Clara University’s (SCU’s) Robotics Systems Laboratory (RSL). Design of the mechanical subsystems on Nautilus added flexibility of usage and protection of components. The new GUI improved pilot control of Nautilus with an added heads-up display and easy access to sensor readouts. The simulated Nautilus altitude control system has an error of ±1% and a …

The Modular Oceanic Autonomous Underwater Vehicle For Novel Actuation, Bryan Gilbertson, John Elstad, Matthew Holmes, Sean Even, Robert Percell, Andrew Kambe, Gregor Limstrom

Interdisciplinary Design Senior Theses

A low-drag, high endurance, and high efficiency Long Range Autonomous Underwater Vehicle is a desired asset to Santa Clara University to aid future underwater vehicle development efforts. Such an vehicle will demonstrate novel actuation methods and provide the on-campus Robotics Systems Laboratory with a modular prototype to aid research and academic efforts. In this paper, we document the construction of a low cost, modular, demonstration vehicle that satisfies the requirements for high-efficiency operation and modular interfaces. The completed vehicle features standard actuation abilities utilizing low-drag methods that qualify it for shallow water operation. Furthermore, the vehicle demonstrates the feasibility of …

Survey Of Unvented Attics In Climate Zone 2a, Florida Solar Energy Center, Eric Martin

FSEC Energy Research Center®

Moisture risk must be managed in unvented attics to ensure durability of components and longevity of the system. The FSEC Energy Research Center (FSEC), at the University of Central Florida tested and collected data in six homes in the northern Florida portion of IECC Climate Zone 2A built after 2015 with unvented (semi-conditioned) attics to add to the body of knowledge on the accumulation of moisture in the attic and its effects on roof moisture that can impact durability.

Dynamics Of Running Processes In The Area Of Underless Water Intake, D.R. Bazarov, M.P. Tashkhanova, A. Gayur, M. Sapaeva

Irrigation and Melioration

The paper analyzes the dynamics of channel processes based on the results of field studies of the Amudarya River at the site of the damless water intake to the Karshi Magistralny Canal (KMK) and developed recommendations for improving the water intake conditions. Based on the results of field studies of the head section of the inlet channel, an assessment of the state of the Amudarya river bed in the water intake zone was made. The results of studies of the hydraulic and alluvial regimes of the Amu Darya River in the area of the damless water intake are generalized The …

Determination Of The Optimal Hydromodule Of Irrigation Network For Drip Irrigation, R.Zh. Karshiev, A. Urazkeldiev, A.H. Radjabov, A.I. Ernazarov

Irrigation and Melioration

Most of the irrigation canals operating in the country were built in the 60s and 80s of the XX century, their hydraulic parameters were designed and adapted to the irrigation regimes of agricultural crops, mainly for surface irrigation, and the average hydromodule values were 0,8-1,0 l / s. , the hydraulic parameters of the channel are designed to carry large volumes of water in a short period of time. Over the next 3-4 years, the introduction of water-saving technologies in the irrigation of agricultural crops by farms and "Clusters" requires the improvement of hydraulic methods of irrigation management, the use …

Assessment Of The Impact Of Climate Change On Hydrological Processes In The Chirchik River Basin, Kh.Sh. Gafforov, Sh.D. Sh.D.Tursunboev

Irrigation and Melioration

The importance of assessing past and future climate differences plays an important role in future planning in relation to climate change. This situation requires urgent and concerted action in several areas: technology, infrastructure, politics, economics, and the environment. The article evaluates the impact of changes in precipitation intensity on the water level in the global circulation model (GCM) RCP 4.5 and 8.5 scenarios in the 2030s, 2050s, and 2070s. This study is a useful reference for improving water resource management and ensuring the sustainability of agricultural products in the future, as well as for improving operational water management and agricultural …

Assessment Of The Impact Of Climate Change On Hydrological Processes In The Chirchik River Basin, В.K. Saliev

Irrigation and Melioration

The article examines the assessment of the state and problems of irrigation water use in the republic in the past and in the near future. A comparative analysis of the state of water resources use for the period of the last 30 years from 1989 to 2019 was carried out.According to the estimates, own water withdrawal for 5 years (2014/15-2018/19) shows that an average of 53.2 m3, including 50.5 billion m3 from rivers At present (2018-2019), an average of 57.06 billion m3 of water is taken for irrigation of 4.289 million hectares of land, against 63.02 billion m3 approved in …

Environmental Damage Caused By Transport Equipment Waste, M. Radkevich, K. Shipilova, M. Abdukodirova, O. Pochugevski

Irrigation and Melioration

The article suggests a new approach to the monetary assessment of the damage caused to the environment by the processed waste of the transport sector. The proposed assessment method is based on the waste collection factor, all types of irretrievable losses and the volume of necessary compensatory release of materials. Based on a survey among vehicle owners, it was found that the solid waste collection rate is about 50 %, while the waste collection rate for operating fluids does not exceed 32 %. In this regard, the bulk of the damage to the environment is caused by liquid waste. Calculations …

Research Of Stress-Deformed State Of Multi-Connected Complex Shell Structures, Т.М. Маvlanov, Sh.O. Khudainazarov, B. Yalgashev, O.S. Nurova

Irrigation and Melioration

Conducting numerical experiments for complex structurally inhomogeneous structures allows us to understand the qualitative picture of the effect of various parameters in a wide range of studies and to give sound recommendations at the design stage for conducting laboratory model and field experiments. In this paper, on the basis of the classical theory of elasticity, the basic equations characterizing the stress-strain state of complex multiply connected shell structures are given and a specific problem is solved. At the same time, some of the structural elements have viscoelastic properties. When solving the problem, the behavior of the structure for the n-th …

To The Determination Of The Critical Circuit Speed Of The Sharing Drum, Kh. Kh. Igamberdiev, A.B. Mukhitdinov

Irrigation and Melioration

The article is devoted to the theoretical definition of the critical circumferential speed of the stripping drum of a kena harvester, which depends on the drum diameter, diameter and weight of the stems. It was determined from the equality of the change in the momentum of the stem during impact, i.e. from a shock impulse acting on the stem. The shock impulse is determined when the drum blade touches the stem in the process of stripping, which acts on the mass of the entire stem. The duration of the impact of the drum stripping on the stem was determined from …

An Innovative Seeder For Sowing Non-Loose Seeds Of Saxaul And Cherkez, E.T. Farmonov

Irrigation and Melioration

The main reasons for the absence of a seeder for mechanized sowing of non-loose seeds of fodder plants in deserts are analyzed in the article. The author has developed a technology for sowing non-loose seeds (saxaul and cherkez), which prevents clogging, crushing and breakage in the seeder hopper, and provides for uniform and stable sowing at a set rate and shallow depth over the entire field area without reducing the biological germination. An innovative seeder with a universal sowing unit is recommended. Field tests of the innovative seeder with the proposed universal sowing unit were conducted in February 2020, as …

Recommendations For The Analysis And Safety Assessment Of Turbid Sediments In Flood Reservoirs, А. Yangiev, Sh. Panjiev, D. Adjimuradov

Irrigation and Melioration

The article presents the results of field research conducted in Langar, Dehkanabad, Shurabsoy flood reservoirs in the Kashkadarya region.There are many problems as a result of floods in the reservoirs, there are disturbances in the discharge and drainage facilities during the passage of accidental floods.At the same time, there was a large accumulation of turbid-sediments in flood reservoirs.In the article, the results of the calculations using empirical formulas for predicting the amount of turbid sediments in Langar, Dehkanabad, Shurabsoy flood reservoirs up to 2025-2030 years are also presented, and it is noted that at present their useless volumes are full …

Justification Of Parameters Of Replaceable Working Parts Of A Combined Machine, А.A. Akhmetov, L.B. Muratov

Irrigation and Melioration

In article are described the design and options for completing the replaceable working parts of the combined machine for continuous tillage which of the formation of ridges and ridges for sowing re-crops. The parameters of the ridge former and apron-leveler of this machine have been substantiated. The rational values of the parameters of the comb-former are: length 600 mm, width of the entrance edge 680 mm, height of the blade 160 mm, length of the side edge of the blade 178 mm. The rational values of the working length and height of the leveling apron are 220 mm and 200 …

Development Of An Algorithm For Optimization Of Continuous Technological Process Of Cultivation Of Microorganisms, Sh.R. Rakhmanov

Irrigation and Melioration

In article the analysis of possible modes of microalgae cultivation has been carried out. Two optimization algorithms are substantiated. The first one is based on the method of random search with an absolute bias, an algorithm for optimizing the process of cultivating microorganisms with continuous regeneration of the flow in one cultivator. The second is an algorithm for determining the optimal residence time of chlorella particles in multistage cultivators, focused on the method of dynamic programming, implemented in Wellman's recurrence relation. The developed algorithm for operational forecasting and automatic control of the chlorella cultivation process allows, under given production conditions …

Covid-19 Impact To Family Food Consumption And Income In Uzbekistan: Results Of An Online Survey, Kh. Pardaev, Sh. Hasanov, S. Mamasoliev, Sh. Muratov, R. Kalandarov, U. Nurullaev

Irrigation and Melioration

This article aims to study the impact of the pandemic on food consumption by families in Uzbekistan. The shock of the pandemic is threatening the well-being of families in Uzbekistan, as in all developing countries. The study focuses on the effects of changes in food prices, declining consumption, and changes in household incomes. The Instrumental regression model was used in the factor impact analysis. Data for analysis were collected online by messenger groups from families in urban and rural areas of Uzbekistan. Results of the Econometric analysis demonstrated that the decline in food consumption in households was assessed by a …

Status Of Crop Diversification And Its Empirical Analysis: A Case Study Of The Republic Of Uzbekistan, A.E. Primov

Irrigation and Melioration

The main objective of this study is to determine the status and level of crop diversification among farms in the country through an empirical analysis using panel data collected in 2009-2017. In doing so, we performed the Stata-16 software using the Simpson Diversification Index model in determining the diversification index. According to the results, the highest diversification indicators were found for Samarkand, Fergana and Tashkent regions, respectively, and accounted for 0.74, 0.74 and 0.76, respectively. It can be seen that the existing farms in Tashkent region used more diversified crops than in other regions of the country. The average diversification …

Efficiency Of Using Graphic Software In The Design Of Hydrotechnical Structures, U.A. Nasritdinova, A.M. Khodjaev, Z.I. Kayumova

Irrigation and Melioration

The article examines the work of scientists engaged in research in this area in the design of hydrotechnic structures. The possibilities of design programs for the application of the results of scientific research in the educational process were used. Thanks to the design in these programs, practical tasks are carried out with the utmost precision. The use of computer technology in teaching the subject "Hydrotechnical structures" and the use of graphic software AutoCAD in the design of linear platforms for clothing, curved platforms for clothing from hydrotechnical structures are shown in 2D and 3D three-dimensional modeling.

Étude De L’Applicabilité De Haut-Parleurs Paramétriques Au Développement De Nouveaux Concepts D’Alarmes De Recul, Olivier Robin, Alain Berry, Hugues Nélisse

Rapports de recherche scientifique

L’utilisation d’alarmes de recul est obligatoire sur une majorité de véhicules lourds et reste un moyen largement utilisé pour prévenir et alerter les personnes œuvrant à proximité de ces véhicules. Des études antérieures, réalisées par l’IRSST, ont montré les limites d’efficacité des alarmes utilisées en milieu de travail pour minimiser le risque à la sécurité des travailleurs. De plus, les alarmes de recul, par le son de niveau élevé et très typé qu’elles produisent, sont régulièrement une source de nuisance importante pour les travailleurs, et aussi pour les riverains. Ces problèmes de gêne et de perception sonore pour les travailleurs …

Thermoelectric Generation And Thermophysical Properties Of Metal Oxide Nanofluids, Xinran Hou, Rong-Tsu Wang, Shaowen Huang, Jung-Chang Wang

Journal of Marine Science and Technology–Taiwan

This study describes the comprehensive characterization of the diverse water-based nanofluids involving aluminum oxide, titanium dioxide, and zinc oxide nanoparticles, which were prepared through the two-step synthesis method assisted by a microemulsion ultrasound skill with effects of both weight-percent concentration (wt.%) in the range of 1.0% and 5.0% and between 20 ^oC and 40 ⁰C. The mean cluster size, zeta potential, pH value, viscosity, thermal conductivity, absorbance, light absorption, and electrical charge density of the various nanofluids were surveyed by relative experiments. The results showed that the 2 wt.% Al₂O₃, 2 wt.% TiO_{2 …}