Engineering Science and Materials Commons^™

Interaction Of Optomechanical Cavities With Acoustic Waves And Oscillators, Ke Huang

Optical Science and Engineering ETDs

Resonators and oscillators are key elements in a wide variety of natural and manmade systems. As such understanding and exploiting their dynamics both as isolated devices and members of coupled systems has been the subject of intensive investigation for more than a century. The advent of optomechanical resonators (OMRs) that support strong coupling between optical and mechanical modes resulting in self-sustained optomechanical oscillations, has created new opportunities for device development and implementation of coupled oscillatory systems. One aspect of this thesis is focused on exploring some of the unique features of OMRs and optomechanical oscillators (OMOs) that can be exploited …

Comparison Of Plantar Pressure Profile Of Young Adults During Training On Elliptical Devices And Overground Walking: A Pilot Study, Guilherme Manna Cesar, Thad W. Buster, Judith M. Burnfield

Department of Mechanical and Materials Engineering: Faculty Publications

Background: Elliptical training may offer advantages over other cardiorespiratory exercises for those requiring podiatric care, since its constant double-limb support diminishes recurring high-impact plantar forces while allowing exercise in a functional, upright posture. Unknown is the impact of distinct elliptical models, that can alter user’s body mechanics, on potential variations in plantar pressure patterns.

Purpose: To compare plantar pressure variables while exercising on four ellipticals and walking.

Methods: For this cross-sectional pilot study, plantar pressure data were recorded from ten young adults while exercising on four ellipticals (True, Octane, Life Fitness, SportsArt) and walking overground. One-way repeated measures ANOVA identified …

Magnetically Induced Carrier Distribution In A Composite Rod Of Piezoelectric Semiconductors And Piezomagnetics, Guolin Wang, Jinxi Liu, Wenjie Feng, Jiashi Yang

Department of Mechanical and Materials Engineering: Faculty Publications

In this work, we study the behavior of a composite rod consisting of a piezoelectric semiconductor layer and two piezomagnetic layers under an applied axial magnetic field. Based on the phenomenological theories of piezoelectric semiconductors and piezomagnetics, a one-dimensional model is developed from which an analytical solution is obtained. The explicit expressions of the coupled fields and the numerical results show that an axially applied magnetic field produces extensional deformation through piezomagnetic coupling, the extension then produces polarization through piezoelectric coupling, and the polarization then causes the redistribution of mobile charges. Thus, the composite rod exhibits a coupling between the …

The Use And Explanation Of The Phase Angle In Forced Vibration Testing, Nicholas R. Slavin, Ryan D. Thornton

Architectural Engineering

Forced vibration testing is a tool used to characterize a structure’s dynamic properties. When subjecting a structure to a forced harmonic load, the results help define the structure’s fundamental frequencies and dominant mode shapes. However, when conducting testing, it is difficult to determine the contributions of each mode to the response at a given location in the structure. The recorded response from a forced vibration test is a combination of unknown modal constituents. Excitation may not result in the pure, single mode response that the experimenter desires, but may instead result in a combination of modal responses that obscure the …

Towards A Sociotechnical Reconfiguration Of Engineering And An Education For Ethics : A Critical Realist Investigation Into The Patterns Of Education And Accreditation Of Ethics In Engineering Programmes In Ireland, Diana Adela Martin

Doctoral

The focus of this thesis is on the provision and evaluation of ethics in engineeringprogrammes in Ireland, by placing this examinationin the wider cultural context of engineering education.The study benefitted from the support of the national accrediting body Engineers Ireland, and included 23 engineering programmes from 2 institutes of technology and 4 universities in Ireland which underwent accreditation between 2017-2019.By using a Critical Realistframe, the study undertakes a multi-layeredinvestigation of the engineering education system that takes into consideration theindividual level of single agents such as instructors and evaluators, the institutional level comprised of engineering programmes, as well as the policy …

Dynamics Of Discontinuities In Elastic Solids, Arkadi Berezovski, Mihhail Berezovski

Publications

The paper is devoted to evolving discontinuities in elastic solids. A discontinuity is represented as a singular set of material points. Evolution of a discontinuity is driven by the configurational force acting at such a set. The main attention is paid to the determination of the velocity of a propagating discontinuity. Martensitic phase transition fronts and brittle cracks are considered as representative examples.

Development Of High-Density Propulsion System Technologies For Interplanetary Small Satellites And Cubesats, Morgan Andrew Roddy

Graduate Theses and Dissertations

The goal of this research was to support the development of a novel propulsion system for small satellites (<180 kg) and CubeSats. This was pursued by conducting a collection of studies that were designed to provide engineering data that would be critical in designing a functional prototype. The novel propulsion system was conceived by the author to provide best-in-class performance for the small satellite and CubeSat families of spacecraft. This context presents specific design requirements that the presented technology attempts to satisfy. The most critical among these is high density; the propellant was designed to be stored with high density and the thruster was designed to be as compact as possible. The propulsion system is composed of two primary elements, a propellant generator and a thruster. The propellant generator works by sublimating a solid crystal into vapor and then using this vapor to etch a dense metal. The resulting gaseous byproducts of this reaction are the propellant. This dissertation used xenon difluoride (XeF2) vapor to etch tungsten (W) which react to form xenon gas (Xe) and tungsten hexafluoride (WF6). This approach gave a theoretical propellant storage density 5.40 g/cm3; and 5.17 g/cm3 was demonstrated. The sublimation dynamics of the XeF2 were studied as a function of surface area and temperature and it was found to be suitable for the intended application due to its high effluence rate; that is, it sublimates fast enough to be useful. The sublimation rates are on the order of 10’s of µg/s. The etch rate of XeF2 on W was also studied and found to be suitably fast to provide useful amounts of reactants for use as a propellant, again on the order of 1’s of µg/s. The thruster is an electrostatic radio frequency (RF) ion thruster design and is manufactured with Low Temperature Co-Fired Ceramic (LTCC) materials system and manufacturing technology. Manufacturing samples of the thruster were built at the University of Arkansas in July 2015 and tested at NASA’s Marshall Space Flight Center in May 2018. Testing validated the viability of the LTCC thruster and provided valuable information on how to improve the thruster’s design.

Long-Term Durability Of Solar Photovoltaic Modules, Chibuisi Chinasaokwu Okorieimoh, Brian Norton

Conference papers

Solar photovoltaic (PV) panels experience long-term performance degradation resulting in lower like-per-like efficiencies and performance ratios when compared with their initial performance. Manufacturers of solar photovoltaic modules usually guarantee the life span for more than 20 years. It is therefore necessary to track and mitigate degradation of PV modules over this period to satisfy such guarantees and beyond this period to identify maintenance and repair requirements. Degradation of solar PV modules makes them less efficient, less reliable and, ultimately, inoperative. This paper reviews relevant literature to discuss:

• Causes of efficiency reductions in photovoltaic cells

• Ways to achieve long-term durability of …

Poly(Ethylene Oxide) Based Polymer Electrolytes For All-Solid-State Li-S Batteries, Xue Li, Zheng-Liang Gong

Journal of Electrochemistry

In recent years, research on lithium-sulfur (Li-S) batteries has received much attention because the sulfur positive electrode and the lithium metal negative electrode produce a high theoretical specific capacity (lithium metal ~ 3800 mAh·g^-1, sulfur ~ 1675 mAh·g^-1). In addition, sulfur is considered to be the most promising cathode material for secondary lithium batteries, due to its advantages of low price and environmental friendly. However, the practical application of conventional liquid Li-S batteries is still obstructed by several critical issues, such as lithium ploysulfides shuttle effect, long-term stability of lithium metal anode with organic liquid electrolytes, …

Synthesis And Raman Study Of Hollow Core-Shell Ni1.2Co0.8P@N-C As An Anode Material For Sodium-Ion Batteries, Jia-Hui Chen, Xiao-Bin Zhong, Chao He, Xiao-Xiao Wang, Qing-Chi Xu, Jian-Feng Li

Journal of Electrochemistry

With the increasing demand for large-scale energy storage, great progress has been made in discovering new advanced energy storage materials. Sodium-ion batteries (SIBs) have attracted much attention in recent years due to their use of abundant sodium resources and their comparable electrochemical capacity to lithium-ion batteries (LIBs). In this paper, we developed novel hollow core-shell Ni-Co bimetallic phosphide nanocubes with N-doped carbon coatings (Ni_1.2Co_0.8P@N-C) as the anode material for SIBs. The material was synthesized through a low-temperature phosphorization method using resorcinol formaldehyde (RF) resin coating with a Ni-Co Prussian blue analogue (PBA) as a template and …

Preparations Of Nano-MnoX/Ti Electrocatalytic Membrane Electrode For Catalytic Oxidation Of Cyclohexane Using Intermittent Electrodeposition, Xue Zhou, Hong Wang, Zhen Yin, Yu-Jun Zhang, Jian-Xin Li

Journal of Electrochemistry

Cyclohexanone and cyclohexanol (KA oil) obtained from highly selective oxidation of cyclohexane (CHA) show important industrial value and application prospects. In this work, the intermittent electrodeposition was developed to prepare nano-MnO_x catalyst loading porous tubular titanium membrane electrode (MnO_x/Ti), which was employed to constitute an electro-catalytic membrane reactor (ECMR) for the oxidation of cyclohexane to produce cyclohexanol and cyclohexanone. The surface morphology, crystal structure and electrochemical property of the catalysts were characterized by FESEM, XRD and electrochemical workstation, respectively. The results show that the catalyst prepared by the intermittent electrodeposition displayed nano-flower-like γ-MnO₂. Compared with …

Preparation Of Α-Hydroxylated Acetal From 2-Butanone By Indirect Electrooxidation, Hai-Qing Huang, Ye Miao, Xin-Sheng Zhang

Journal of Electrochemistry

Acetoin (3-hydroxy-2-butanone) is an important food spice. As a platform compound, it is widely used in medicine, tobacco, cosmetics, chemical material and other industries. In this paper, α-hydroxylated acetal, an intermediate of acetoin, was prepared from 2-butanone by indirect electrooxidation in the plate and frame electrolytic cell, in which graphite plates were used as both an anode and a cathode, while KOH as an electrolyte and KI as a catalyst. Acetoin could be prepared by hydrolysis in acidic aqueous solution from acetoin intermediate. The effects of current density, electrolyte flow rate between the plates, 2-butanone concentration and electrolysis temperature …

Electrochemical Oxidation Of Metal Chromium In Odium Hydroxide Aqueous Solution, Ping Han, Hai-Tao Feng, Ya-Ping Dong, Sen Tian, Bo Zhang, Wu Li

Journal of Electrochemistry

Ferrochrome electrolysis technology is a novel method for preparing sodium chromate (Na₂CrO₄). Although the method performs well at soft reaction conditions, controllable process, environmentally friendly production process, etc., the electrochemical oxidation process of metal chromium in NaOH aqueous electrolyte is still unclear. At present, there are few research articles about specific electrochemical oxidation of metal chromium in NaOH aqueous electrolyte. It is, therefore, meaningful to carry out the research in electrochemical oxidation mechanism of chromium. The electrochemical oxidation of metal chromium in 0.01 mol·L^-1 ~ 10 mol·L^-1 NaOH aqueous electrolytes at 20 °C was …

Electrochemical Response Of A Single Wire-Electrode Ac Probe In 3.5wt.% Nacl, Zhen-Wen Zou, Da-Jiang Zheng, Zi-Ming Wang, Guang-Ling Song

Journal of Electrochemistry

In this paper, a recently developed single wire-electrode AC probe technology which does not need a reference or counter electrode was employed to investigate the electrochemical corrosion and sacrificial anode protection behaviors of steel and zinc in 3.5wt.% NaCl. With this simple, fast, reliable and stable probe, the instantaneous corrosion rate and accumulated corrosion loss of carbon steel in 3.5wt.% NaCl were measured, and the results revealed that both were greater than those of zinc. Furthermore, the observed different corrosion behaviors between carbon steel and zinc during the immersion could be caused by their different surface films. With the galvanic …

Stability Studies For A Membrane Electrode Assembly Type Co2 Electro-Reduction Electrolytic Cell, Qing Mao, Bing-Yu Li, Wei-Yun Jing, Jian Zhao, Song Liu, Yan-Qiang Huang, Zhao-Long Du

Journal of Electrochemistry

Electro-catalytic reduction is an efficient way to achieve resourcable transformation of CO₂, which is one of the important techniques to solve the global environmental problems originated from excessive CO₂ emission. In this study, a membrane electrode assembly(MEA) type CO₂ electro-reduction electrolytic cell was constucted, which enables CO₂ feeding and real-time KHCO₃ aqueous updating on both sides of the cathode gas diffusion electrode (GDE). By means of the electrolytic cell, effects of KHCO₃ concentration and updating inside the liquid electrolytic chamber on CO₂ electro-reduction activity, production distribution and stability were investigated. The experimental …

Degradation Mechanism Of Lini0.83Co0.12Mn0.05O2 Cycled At 45 ℃, Hong-Yun Ma, Xiao-Hui Yao, Meng-Yao Miao, Yang Yi, Shao-Zhong Wu, Jiang Zhou

Journal of Electrochemistry

Nickel-rich layered material has been considered as the most promising one for lithium ion batteries due to its high specific capacity. To further improve the lifetime performance, it is significant to investigate the degradation mechanisms deeply. In this study, the degradation mechanism of NCM811 (LiNi_0.83Co_0.12Mn_0.05O₂) being cycled at 45^oC was systematically researched. Electrochemical impedance spectrum (EIS) results showed that the SEI resistance (R_SEI) and charge transfer resistance (R_ct) went up to 83.41% and 211.34% before and after the NCM811 material being cycled at 45^oC, …

The Interaction Of Ternary Components Of Ionic Liquid Gel Polymer Electrolytes For Lithium Metal Batteries, Xiao-Na Pan, Li-Lai Liu, Zhi-Pu Wang, Dan Wang, Yun Li, Pei-Xia Yang, Jin-Qiu Zhang, Mao-Zhong An

Journal of Electrochemistry

Ionically conductive gel polymer electrolyte is an excellent candidate due to its inflammable, nonvolatile and high thermal stability as compared to commercial liquid electrolytes which are usually flammable, volatile, and containing toxic organic solution as solvent, The synthesis and application of ionic gel polymer electrolytes in lithium ion/metal batteries have been previously reported. However, the interaction effects of N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13TFSI) ionic liquid (as plasticizer) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) on PVDF-HFP polymer remain unclear. In this work, the molecular structure of ionic liquid gel polymer electrolyte (ILGPE) composed of PP13TFSI, LiTFSI and PVDF-HFP was studied by Raman spectroscopy and Fourier-transform …

Ordered Mesoporous Carbon/Graphene/Nickel Foam For Flexible Dopamine Detection With Ultrahigh Sensitivity And Selectivity, Lai-Yu Wang, Xin Xi, Dong-Qing Wu, Xiong-Yu Liu, Wei Ji, Rui-Li Liu

Journal of Electrochemistry

Electro-catalytic reduction is an efficient way to achieve resourcable transformation of CO₂, which is one of the important techniques to solve the global environmental problems originated from excessive CO₂ emission. In this study, a membrane electrode assembly(MEA) type CO₂ electro-reduction electrolytic cell was constucted, which enables CO₂ feeding and real-time KHCO₃ aqueous updating on both sides of the cathode gas diffusion electrode (GDE). By means of the electrolytic cell, effects of KHCO₃ concentration and updating inside the liquid electrolytic chamber on CO₂ electro-reduction activity, production distribution and stability were investigated. The experimental …

Open-Source Digitally Replicable Lab-Grade Scales, Benjamin R. Hubbard, Joshua M. Pearce

Michigan Tech Publications, Part 1

This study provides designs for a low-cost, easily replicable open-source lab-grade digital scale that can be used as a precision balance. The design is such that it can be manufactured for use in most labs throughout the world with open-source RepRap-class material extrusion-based 3-D printers for the mechanical components and readily available open-source electronics including the Arduino Nano. Several versions of the design were fabricated and tested for precision and accuracy for a range of load cells. The results showed the open-source scale was found to be repeatable within 0.05 g with multiple load cells, with even better precision (0.005 …

Influence Of Elements Of Irrigation Equipment On Irrigation Erosion, M.M. Sarimsakov, O.S. Abdisamatov, Z.T. Umarova

Irrigation and Melioration

Irrigation erosion is a process that has a significant negative impact on agricultural production, which leads to a sharp decrease in soil fertility and productivity. The costs associated with growing crops will increase. Today, more than 720,000 irrigated lands in the country suffer from irrigation erosion. Studies have shown that in typical gray soils with a slope of more than 0.30, intensive irrigation of apple orchards leaches 24.6 tons of soil particles per hectare per season. Improved irrigation, that is, a decrease in the leaching of soil particles during irrigation using transverse barriers, was achieved by 6–12%. Irrigation reduces the …

Research Of Water Flow Motion In The Channel Of Amu-Bukhara Machine Channel, D.R. Bazarov, F. Artikbekova, M.P. Tashkhanova, B.M. Norkulov

Irrigation and Melioration

The article considers a numerical study of the movement of a water stream in the channel of the Amu Bukhara Machine Channel (ABMK). Water intake to the inlet canal is carried out from the Amu Darya river in a damless manner, therefore, ensuring the flow of clarified water into the anterior chambers of pumping stations is an urgent task. According to the developed model, consisting of hydrodynamic equations based on the laws of conservation of momentum and mass, data on the dynamics of velocities in the channel of the supply channel ABMK are obtained and zones of uneven flow in …

Irrigation Value The Mechanical Composition River Springs, A.M. Arifjanov, L.N. Samiev, F.K. Babajanov

Irrigation and Melioration

The article studies the influence of the fractional composition of river sediments on the soil structure of irrigated lands and on the process of soil formation. According to surveys in the Mirishkor canal, sediments formed in the river are distinguished by the distribution type in the main canal. The fractional composition of sediments mainly consists of particles of fine sand (0.1-0.05 mm) and coarse dust (0.05-0.001 mm).According to the results of surveys, by studying the mechanical composition of sediment in the channel, it will be possible to observe changes in the amount of composition, such as N-NH4, P2O5, K2O chemicals. …

Monitoring System For Electricity Consumption At Pumping Stations, N. Ikramov, T. Majidov, A. Mukhammadjonov

Irrigation and Melioration

Currently, in Uzbekistan, of 4.3 million hectares of irrigated land, 2.3 million hectares are provided with water supplied by pumping stations that are on the balance of the Ministry of water management of the Republic of Uzbekistan. In total, 1693 pumping stations with 5301 pumping units are operated, and the number of pumping stations ' personnel is about 16,000 people. The total capacity of these pumping stations is about 7000 m3/s. the Total annual energy consumption of these pumping stations is about 8.0 billion kW·h or about 12.5% of the annual electricity generation of the entire energy sector of Uzbekistan. …

Irrigation Value The Mechanical Composition River Spring The Effect Of The Inhomogeneity Of Elastic Medium On The Initiation Of Resonant Waves Under Moving Load, S.A. Abdukadirov, Z.S. Shаdmаnova, B.Sh. Yuldoshev

Irrigation and Melioration

investigated. The waveguide properties of the system are preliminarily studied. The multiple roots of the dispersion equations are revealed and the critical load velocities leading to the formation of resonance processes are determined. The solutions of the dispersion equations make it possible to determine the additional critical velocities in the mid-wave spectrum depending on the structure parameters. For simple models, analytical solutions of the development of resonance processes are obtained that are asymptotically correct for relatively large values of time. The computer simulations allow us to analyze the quantitative features of the process over the entire time period of the …

Substantiation Of Sprayers Installed To A Universal Mounted Sprayer, D. Dzhuraev, M.S. Halilov, S.M. Badalov, I.Zh. Toirov, A.E. Urishev

Irrigation and Melioration

The article presents the results of theoretical and experimental studies on the creation of primary sprayers for sprayers. The flow diagrams of the atomizers that were produced on the territory of the former Soviet Union are given. Currently, various types of spray guns are manufactured in America, Germany, France, Italy, Bulgaria and other countries. Based on the set requirements for sprayers, to ensure fluid flow and spraying when deployed 90-110 degrees on a plane, a slotted sprayer is selected - manufacturer Lechler of the brand ST-110-05 Germany, for installation on a universal mounted sprayer. The results of fluid flow by …

Technological Features Of Moistening Of Technical Seeds, O. Matchanov, B. Tuxtamishev

Irrigation and Melioration

This article describes the technological features of the reduction of technical varieties of cotton. Requirements for technical seeds in the processing of raw cotton are technical specifications and quality indicators. Seeds of technical cotton with quality indicators and adapted technical seeds must meet the requirements of technical conditions. The technical need for coated seeds should correspond to technical characteristics, such as reducing production costs, reducing moisture, long-term storage, improving quality, thermal conductivity, aerodynamic resistance, and heat resistance. From the point of view of heat treatment of seeds, parameters taking into account their thermophysical properties should be used to justify the …

Regulations Of Hydraulic Resistance Of Machine Channels Of Pumping Stations, D.R. Bazarov, B.R. Uralov, M.P. Tashkhanova

Irrigation and Melioration

The paper considers the general equation of fluid motion in the channels and the functional dependences of the hydraulic friction coefficient on the Reynolds number, relative roughness, and on the shape of the live section of the channel. Resistance formulas are given for the simplest cross-sectional shapes of channels and for channels with a more complex cross-sectional shape. To take into account the effect (on the pressure loss) of the channel cross-sectional shape and the presence of a flow with a free surface in it, additional correction factors are introduced (using the hydraulic radius concept) and be clarified as a …

Studying The Movement Of Crop Drined Seeds Of Cottage On A Slope Tray In A Protective Machine, R.K. Djamolov, A.A. Akrаmov, K. Djamolov

Irrigation and Melioration

The article presents the results of a theoretical study of the movement of pubescent cotton seeds along an inclined guide in a pickling machine. Equations are obtained that describe the movement of the seed along the inclined tray of the dresser. A formula is derived for determining the time of movement of the seed on an inclined one to the dressing agent. A plot of the change in the speed of the seed in the tray on the change in the angle of inclination and on the value of the movement of the seed. To increase the feed rate of …

Modernization Of Functions Of Management Of Land Use In The Conditions Of Innovative Economy, Sh.K. Narbaev

Irrigation and Melioration

Land use management, as a complex material-abstract system, is carried out through a number of its functions. The article provides an analysis of the functions of land management, improved the content of some functions and introduced additional new functions in the context of the development of an innovative economy. It is noted that improving the management system will increase the efficiency of land use, improve their environmental status, preserve landscape ecosystems based on the accelerated development of innovative activities. New land management functions are recommended: innovative land use development, territory development, land use technical support, remote study of land properties …

Combined Installation Photo Thermal Battery - Electric Water Heater To Provide Electricity And Water To Rural Households, R.A. Muminov, M.N. Tursunov, Х. Sabirov, U.R. Kholov, Т.Z. Аkhtamov, М. Eshmuradova

Irrigation and Melioration

The article presents the experimental results of the study of the parameters of a combined installation photo thermal battery – electric heater, used to provide electric energy and water to rural households. Photo thermal battery is made on the basis of photovoltaic batteries of crystalline silicon with an efficiency of ~ 20 %. Cellular polycarbonate was used as a heat sink. When creating the KU based on photo thermal battery EVN, modern efficient batteries, controllers, inverters and consumers of electric energy were used, and Ariston was chosen as the EVN. KU is adapted to climatic conditions, effectively and reliably provides …