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Articles 40501 - 40530 of 196053

Full-Text Articles in Engineering

การบำบัดน้ำล้างดินที่มีการปนเปื้อนน้ำมันปิโตรเลียมด้วยระบบฟอร์เวิร์ดออสโมซิส, ลลิตา หลำพึ่ง Jan 2022

การบำบัดน้ำล้างดินที่มีการปนเปื้อนน้ำมันปิโตรเลียมด้วยระบบฟอร์เวิร์ดออสโมซิส, ลลิตา หลำพึ่ง

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้เป็นการศึกษา การบำบัดน้ำล้างดินจากดินปนเปื้อนน้ำมันปิโตรเลียมด้วยวิธีฟอร์เวิร์ดออสโมซิส และประสิทธิภาพในการล้างดินของสารละลายที่เป็นมิตรต่อสิ่งแวดล้อม โดยทำการสังเคราะห์ดินปนเปื้อนน้ำมันที่ใช้ในการทดลองมีความเข้มข้น เท่ากับ 255,517 มิลลิกรัมต่อกิโลกรัม เมื่อผ่านกระบวนการล้างดินด้วยเอทิลแลคเตต พบว่าน้ำล้างดิน (Rinsed water) มีความเข้มข้นของน้ำมันดีเซลและความเข้มข้นของเอทิลแลคเตต เท่ากับ 267 และ 20,033 มิลลิกรัมต่อลิตร ตามลำดับ ซึ่งนำไปกำหนดช่วงในการออกแบบการทดลอง หาสภาวะการบำบัดที่เหมาะสมของระบบฟอร์เวิร์ดออสโมซิสด้วยวิธีพื้นผิวตอบสนอง (Response surface methodology; RSM) แบบ Central composite design (CCD) โดยมีปัจจัยของสารป้อนที่สนใจทั้งหมด 3 ปัจจัย ได้แก่ ความเข้มข้นของน้ำมันดีเซล ความเข้มข้นของเอทิลแลคเตต และค่าพีเอช จากผลการทดลอง ค่า Normalized flux ใช้เป็นตัวแปรตอบสนองในการวิเคราะห์ พบว่าสภาวะที่เหมาะสม คือ ความเข้มข้นน้ำมันดีเซลและความเข้มข้นของเอทิลแลคเตต เท่ากับ 100 และ 16,000 มิลลิกรัมต่อลิตร ตามลำดับ และค่าพีเอช เท่ากับ 6 โดยค่า Normalized flux สูงสุด เท่ากับ 0.56 หลังเดินระบบ 3 ชั่วโมง พบว่า เมมเบรนยอมให้เอทิลแลคเตตผ่านได้ 1.46 เปอร์เซ็นต์ ในขณะที่ป้องกันการแพร่ผ่านของน้ำมันได้ 98 เปอร์เซ็นต์ นอกจากนี้ การมีตะกอนในระบบจะส่งผลต่อการบำบัดทำให้ Normalized flux ลดลง ซึ่งสารดึงที่ได้จากการบำบัดน้ำล้างดินด้วยฟอร์เวิร์ดออสโมซิส มีประสิทธิภาพในการบำบัดน้ำมันออกจากดินปนเปื้อน เท่ากับ 77 เปอร์เซ็นต์

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A Risk-Based System For Managing Construction Claim Causes: An Integrated Interpretative Structural Modeling And Bayesian Network Approach, Sang Quang Van Jan 2022

A Risk-Based System For Managing Construction Claim Causes: An Integrated Interpretative Structural Modeling And Bayesian Network Approach, Sang Quang Van

Chulalongkorn University Theses and Dissertations (Chula ETD)

Claims are troublesome and often lead to adverse impacts on construction projects, such as delays, cost overruns, and disputes among contracting parties. Numerous studies have been conducted to improve the understanding of claim causes; however, most previous research works have investigated claim causes individually and ignored the interdependences among claim causes. In addition, the determination of response strategies and methods for claim causes has scarcely been addressed. This research develops a risk-based system for managing claim causes in building construction projects. The main objectives of this research are twofold: (1) to quantify the impacts of claim causes considering their interdependences, …

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Assembly Of Alumina Particles In Aqueous Suspensions Induced By High‐Frequency Ac Electric Field, James E. John, Shizhi Qian, Dipankar Ghosh Jan 2022

Assembly Of Alumina Particles In Aqueous Suspensions Induced By High‐Frequency Ac Electric Field, James E. John, Shizhi Qian, Dipankar Ghosh

Mechanical & Aerospace Engineering Faculty Publications

The role of high-frequency alternating current (AC) electric field in the assembly of alumina particles in aqueous media was investigated. Field–particle interactions were in situ investigated for coarse and fine powder particles in very dilute suspensions. For both coarse and fine particles, AC field-induced assembly led to the formation of chains of particles within a minute, which were aligned in the field direction. However, a much finer network of particle chains evolved in fine particle suspensions. Threshold field strength for chain formation was also lower for fine particles (28 V/mm) than for coarse particles (50 V/mm), suggesting stronger interactions for …

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Can We Make Our Robot Play Soccer? Influence Of Collaborating With Preservice Teachers And Fifth Graders On Undergraduate Engineering Students' Learning During A Robotic Design Process (Work In Progress), Krishnanand Kaipa, Jennifer Kidd, Julia Noginova, Francisco Cima, Stacie Ringleb, Orlando Ayala, Pilar Pazos, Kristie Gutierrez, Min Jung Lee Jan 2022

Can We Make Our Robot Play Soccer? Influence Of Collaborating With Preservice Teachers And Fifth Graders On Undergraduate Engineering Students' Learning During A Robotic Design Process (Work In Progress), Krishnanand Kaipa, Jennifer Kidd, Julia Noginova, Francisco Cima, Stacie Ringleb, Orlando Ayala, Pilar Pazos, Kristie Gutierrez, Min Jung Lee

Mechanical & Aerospace Engineering Faculty Publications

This work-in-progress paper describes engineering students’ experiences in an NSF-funded project that partnered undergraduate engineering students with pre-service teachers to plan and deliver robotics lessons to fifth graders at a local school. This project aims to address an apparent gap between what is taught in academia and industry’s expectations of engineers to integrate perspectives from outside their field to solve modern societal problems requiring a multidisciplinary approach. Working in small teams over Zoom, participating engineering, education, and fifth grade students designed, built, and coded bio-inspired COVID companion robots. The goal for the engineering students was to build new interprofessional skills, …

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Recent Analytic Development Of The Dynamic Q-Tensor Theory For Nematic Liquid Crystals, Xiang Xu Jan 2022

Recent Analytic Development Of The Dynamic Q-Tensor Theory For Nematic Liquid Crystals, Xiang Xu

Mathematics & Statistics Faculty Publications

Liquid crystals are a typical type of soft matter that are intermediate between conventional crystalline solids and isotropic fluids. The nematic phase is the simplest liquid crystal phase, and has been studied the most in the mathematical community. There are various continuum models to describe liquid crystals of nematic type, and Q-tensor theory is one among them. The aim of this paper is to give a brief review of recent PDE results regarding the Q-tensor theory in dynamic configurations.

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Optimization Model For Maintenance Planning Of Loading Equipment In Open Pit Mines, Farshid Javadnejad, Mohammad Reza Sharifi, Mohammad Hossein Basiri, Bakhtiar Ostadi Jan 2022

Optimization Model For Maintenance Planning Of Loading Equipment In Open Pit Mines, Farshid Javadnejad, Mohammad Reza Sharifi, Mohammad Hossein Basiri, Bakhtiar Ostadi

Engineering Management & Systems Engineering Faculty Publications

Maintenance plays a significant role in operating costs in the mining industry. Improving this matter controls maintenance costs and enhances productivity and production effectively. Shovels are one of the most widely used loading machines in non-continuous activities. Thus, evaluating and optimizing their availability is one of the essential solutions to achieving high productivity and cost reduction. This paper presents a mathematical programming model to maximize availability and minimize the total expected costs. We programmed the proposed nonlinear planning model using the Symbiotic Organisms Search (SOS) meta-heuristic algorithm in Matlab software. It determines the optimal maintenance intervals for different parts of …

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Effort And Prospective On Nuclear Security In Rok, Jung Soo Kim, Myung-Tak Jung, Kookheui Kwon, Youngwook Lee Jan 2022

Effort And Prospective On Nuclear Security In Rok, Jung Soo Kim, Myung-Tak Jung, Kookheui Kwon, Youngwook Lee

International Journal of Nuclear Security

As of July 2013, the Republic of Korea (ROK) has been operating a total of 23 nuclear power reactors at four sites with five new reactors under construction. In addition, the country has planned to construct two more units at two candidate sites, but due to a change in the energy policy, only one candidate site has been constructed while the other was decommissioned. The ROK has also been exporting nuclear power plants to the United Arab Emirates (UAE) and building a research reactor in Jordan. These actions have made the nation’s nuclear industry by far the fastest growing industry …

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Women In Nuclear Science & Technology In India: Challenges & Opportunities, Arpita Datta, Dr. Alpana Goel, Ashok Kumar Jain Jan 2022

Women In Nuclear Science & Technology In India: Challenges & Opportunities, Arpita Datta, Dr. Alpana Goel, Ashok Kumar Jain

International Journal of Nuclear Security

Women have been actively contributing toward frontline research and development of various advanced technologies in the nuclear domain and playing a crucial role in key positions. However, proportional representation of women in various decision-making positions at higher levels in politics, diplomacy, military affairs, science, and technology remains low, and most of these positions remain male-dominated. We see that women often find it difficult to achieve leadership roles for several reasons, but often from an implicit bias in society. The stereotypical image of women in society is still propagated very discreetly. In recent times, Indian women have made big strides in …

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The Role Of Nuclear Forensics For Determining The Origin Of Nuclear Materials Out Of Regulatory Control And Nuclear Security, Lekhnath Ghimire, Edward Waller Jan 2022

The Role Of Nuclear Forensics For Determining The Origin Of Nuclear Materials Out Of Regulatory Control And Nuclear Security, Lekhnath Ghimire, Edward Waller

International Journal of Nuclear Security

The international community recognizes the rise in theft and illicit trafficking of nuclear materials and radioactive sources—for malicious use and nuclear terrorism—as a serious threat. That is why a well-developed nuclear forensics capability is an integral part of a robust nuclear security program and a key element of nuclear security infrastructure. Both pre- and post-detonation nuclear forensics are vital for controlling theft and illicit trafficking of nuclear materials, as well as identifying and tracing their sources. Nuclear forensics analysis and interpretation processes for nuclear security is a systematic process that includes: (1) sample collection and categorization techniques and (2) detailed …

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Developing Nuclear Security Capacity Of Indonesia’S Police And Security Officer: Lessons From Universitas Gadjah Mada’S Pilot Training, Susetyo Hario Putero Mr Jan 2022

Developing Nuclear Security Capacity Of Indonesia’S Police And Security Officer: Lessons From Universitas Gadjah Mada’S Pilot Training, Susetyo Hario Putero Mr

International Journal of Nuclear Security

Due to an increase in global nuclear security issues, there need to be improvements in human resources and security measures. The Republic of Indonesia is an archipelago country, which makes surveilling for nuclear security threats complicated. Recent radioactive material smuggling incidents proved that Indonesian police and security officers’ knowledge in nuclear security has been challenged and must be improved. In response, Universitas Gadjah Mada’s Nuclear Engineering Program composed a three-day pilot training program for local police and UGM's security officers in 2018. The objective of the training was to improve their capabilities in dealing with nuclear security issues around where …

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Nuclear Security Awareness Survey At A University, Marcia P. Robinson, Naomi German, Destiny B. White, Shraddha V. Rane, Jason Timothy Harris Jan 2022

Nuclear Security Awareness Survey At A University, Marcia P. Robinson, Naomi German, Destiny B. White, Shraddha V. Rane, Jason Timothy Harris

International Journal of Nuclear Security

The concept of assessing safety culture in an organization emerged with its application at the nuclear power industry and has expanded since then. An assessment of nuclear security, on the contrary, is still under-developed, especially at non-nuclear facilities, such as academic institutions and medical facilities. To identify the level of the awareness and understanding of credible nuclear and radiological threats, response preparedness, security culture, and the integrity of nuclear security systems among non-radioactive material users at a university setting; a campus-wide survey was deployed. A total of 3,336 non-radioactive material users, including students, faculty, and staff participated in the survey. …

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การประเมินผลกระทบต่อสุขภาพ และต้นทุนทางสุขภาพที่เกิดจากฝุ่นละอองขนาดเล็กจากการขนส่งผู้โดยสารในเขตกรุงเทพมหานคร และปริมณฑล, ภัสราภา ฉลองกลาง Jan 2022

การประเมินผลกระทบต่อสุขภาพ และต้นทุนทางสุขภาพที่เกิดจากฝุ่นละอองขนาดเล็กจากการขนส่งผู้โดยสารในเขตกรุงเทพมหานคร และปริมณฑล, ภัสราภา ฉลองกลาง

Chulalongkorn University Theses and Dissertations (Chula ETD)

ปัจจุบันโลกของเรากำลังเผชิญกับปัญหาฝุ่นละอองขนาดเล็ก ที่ส่งผลกระทบต่อสุขภาพ โดยเป็นปัจจัยหลักที่ทำให้เกิดการเสียชีวิตก่อนวัยอันควรถึง 4.14 ล้านคน โดยติดลำดับ 4 ของโลก และจากรายงานของกรมควบคุมมลพิษ เมื่อปี พ.ศ. 2564 พบว่า พื้นที่กรุงเทพมหานคร มีค่าฝุ่นละอองขนาดเล็ก เกินค่ามาตรฐานถึง 89 วัน แหล่งกำเนิดที่สำคัญของฝุ่นละอองขนาดเล็กในกรุงเทพมหานคร เกิดจากการจราจรขนส่งเป็นหลัก งานวิจัยนี้จึงมีวัตถุประสงค์เพื่อจัดทำบัญชีการระบายมลพิษอากาศ ประเมินผลกระทบต่อสุขภาพ และต้นทุนทางสุขภาพ ที่มาจากการขนส่งผู้โดยสารทางถนน ทางเรือ และทางราง จากการเดินทางของประชาชน โดยการจัดทำบัญชีการระบายมลพิษอากาศ แบ่งเป็น 2 ส่วน คือ 1) การใช้เชื้อเพลิง และ 2) การผลิตเชื้อเพลิง การประเมินผลกระทบต่อสุขภาพ ประเมินในหน่วยปีสุขภาวะที่สูญเสีย และแปลงเป็นต้นทุนทางสุขภาพในหน่วย บาท ผลการศึกษาสรุปได้ดังนี้ ปี พ.ศ. 2565 และ ปี พ.ศ. 2570 พบว่า สถานการณ์ที่ลดการเดินทางประเภทรถยนต์ส่วนบุคคล 30% เปลี่ยนเป็นการเดินทางด้วยรถไฟไฟฟ้า ในปี พ.ศ. 2565 ลดผลกระทบต่อสุขภาพ เท่ากับ 15,202 ปีสูญเสียสุขภาวะ เทียบเป็นต้นทุนทางสุขภาพ ได้เท่ากับ 9,011 ล้านบาท และในปี พ.ศ. 2570 เท่ากับ 17,178 ปีสูญเสียสุขภาวะ เทียบเป็นต้นทุนทางสุขภาพ ได้เท่ากับ 10,883 ล้านบาท ดังนั้น การกำหนดนโยบายในอนาคต ควรสนับสนุนให้มีการใช้ระบบขนส่งสาธารณะที่เป็นรถไฟไฟฟ้า และลดการใช้รถยนต์ส่วนบุคคล

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Investigating Ground Interactions Of A Rotocraft Landing Vehicle On Titan, Adam Rozman Jan 2022

Investigating Ground Interactions Of A Rotocraft Landing Vehicle On Titan, Adam Rozman

Honors Undergraduate Theses

The exploration of celestial bodies has recently advanced from rovers to rotorcraft. This includes the recent flights of Mars Ingenuity and the upcoming Dragonfly mission to explore the terrain of Saturn’s moon Titan as part of NASA’s New Frontiers Program. Flight-based landers can travel quickly to sites kilometers apart and land in complex terrain. Although cruise conditions for these rotorcrafts are well understood, studies are necessary to understand take-off and landing. In ground effect conditions, a rotor wake impinges and reflects off the ground, creating changes in aerodynamics such as increased lift. Additionally, operating over loose surfaces, the rotors can …

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Investigation Of Pitching And Plunging Motions On A Tandem Wing Configuration, Riley M. Capiro Jan 2022

Investigation Of Pitching And Plunging Motions On A Tandem Wing Configuration, Riley M. Capiro

Honors Undergraduate Theses

From the beginning of the history of flight, inspiration has been drawn from nature. Evolution has spent millions of years optimizing creatures that rely on flight as their means of locomotion. Today, aerial vehicles are very different to those from the time of the Wright brothers. One kind of vehicle that stands to benefit in mimicking nature is the drone, particularly smaller drones. Commonly used today by militaries, industry and civilians, drones are increasingly affordable while also decreasing in size thanks to advancements in electronics and manufacturing methods. The purpose of this thesis is to investigate how pitching and rolling …

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The Early Propagation And Burning Of Hydrogen In The Process Of The Deflagration To Detonation Transition, Rom Amasay Jan 2022

The Early Propagation And Burning Of Hydrogen In The Process Of The Deflagration To Detonation Transition, Rom Amasay

Honors Undergraduate Theses

The safe and efficient propagation of the Deflagration to Detonation Transition (DDT) is a topic that has been researched for many years due to its applications in Aerospace and Mechanical Engineering. DDT is when fire caused by the burning of fuel is accelerated to the upper CJ point on the Rankine Hugoniot curve due to instabilities in the flame and the turbulence caused by these instabilities. The complex flame dynamics that go along with DDT have ensured that the process is yet to be fully understood and defined. This research will work towards observing the early stages of burning hydrogen-air …

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Atomization Of A Liquid Water Jet In Crossflow At Varying Hot Temperatures For High-Speed Engine And Stratospheric Aerosol Injection Applications, Luke Caetano Jan 2022

Atomization Of A Liquid Water Jet In Crossflow At Varying Hot Temperatures For High-Speed Engine And Stratospheric Aerosol Injection Applications, Luke Caetano

Honors Undergraduate Theses

This paper aims to study how varying crossflow burning temperatures from 1100 C to 1800 C affect the liquid droplet breakup, size distribution, and atomization of a liquid water jet injected into a vitiated crossflow. The LJIC injection mechanism was implemented using the high-pressure axially staged combustion facility at the University of Central Florida. The measurement devices used to gather particle data from the exhaust plume were the TSI Aerodynamic Particle Sizer (APS), which measures particles between 0.523 µm and 20 µm, and the Sensirion SPS30 (SPS30), which measures particles between 0.3 µm and 10 µm. Both measurement devices were …

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Intrinsically Mode Reconfigurable Load Modulation Balanced Amplifier Leveraging Transistor's Analog-Digital Duality, Niteesh Bharadwaj Vangipurapu Jan 2022

Intrinsically Mode Reconfigurable Load Modulation Balanced Amplifier Leveraging Transistor's Analog-Digital Duality, Niteesh Bharadwaj Vangipurapu

Electronic Theses and Dissertations, 2020-2023

The communication schemes have rapidly changed the face of the human means of communication. The evolution from one generation to another has triggered many challenges on the design methodologies of RF designers. As the evolution ensued, the spectrally efficient modulation schemes have resulted in the substantial rise of PAPR, the peak-to-average power ratio. To enable the efficient amplification of the high PAPR signals, this thesis explores the areas of Load modulated Balanced amplifiers that can be inherently reconfigured to achieve a better efficiency than the conventional RF power amplifiers that see a significant drop in the efficiency as the signal …

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Autoignition Delay Time Measurements And Chemical Kinetic Modeling Of Hydrogen/Ammonia/Natural Gas Mixtures, Jessica Baker Jan 2022

Autoignition Delay Time Measurements And Chemical Kinetic Modeling Of Hydrogen/Ammonia/Natural Gas Mixtures, Jessica Baker

Electronic Theses and Dissertations, 2020-2023

In recent years, hydrogen-carrying compounds have accrued interest as an alternative to traditional fossil fuels due to their function as zero-emission fuels. As such, there is interest in investigating hydrogen-carrying compounds to improve understanding of the fuels' characteristics for use in high pressure systems. In the current study, the oxidation of ammonia/natural gas/hydrogen mixtures was carried out to study CO formation profiles as well as the ignition delay times behind reflected shock waves in order to refine chemical kinetic models. Experiments were carried out in the University of Central Florida's shock tube facility by utilizing chemiluminescence to obtain OH* emission …

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Broadband Power Amplifier Design With High Power, High Efficiency And Large Back-Off Range, Yuchen Cao Jan 2022

Broadband Power Amplifier Design With High Power, High Efficiency And Large Back-Off Range, Yuchen Cao

Electronic Theses and Dissertations, 2020-2023

As modern communication system technology develops, the demand for devices with smaller size, higher efficiency, and larger bandwidth has increased dramatically. To achieve this purpose, a novel architecture of load modulated balanced amplifier (LMBA) with a unique load-modulation characteristic different from any existing LMBAs and Doherty power amplifiers (DPAs) was presented, which is named as Pseudo-Doherty LMBA (PD-LMBA). Based on a special combination of control amplifier (carrier) and balanced amplifier (peaking) together with proper phase and amplitude controls, an optimal load-modulation behavior can be achieved for PD-LMBA leading to maximized efficiency over extended power back-off range. More importantly, the efficiency …

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Analysis Of Shear Failure In Ultra-High Performance Concrete Beams, Kevin Conway Jan 2022

Analysis Of Shear Failure In Ultra-High Performance Concrete Beams, Kevin Conway

Electronic Theses and Dissertations, 2020-2023

Ultra-high performance concrete (UHPC) is an emerging cementitious material type currently undergoing research in different structural applications. This material is characterized by a compressive strength of 150 MPa (22 ksi), according to the Association Francaise de Genie Civil and the Federal Highway Administration, high tension strength, and high durability. Additionally, UHPC consists of secondary reinforcement in the form of steel or polymeric fibers, which enable UHPC to exhibit tension hardening behavior and tension ductility previously ignored in conventional concrete mixes. Previous research has focused on applications in the transportation and bridge design industries; however, applications in buildings and other heavy …

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Shock Tube And Gas Dynamic Design Considerations And Implementation For Extended Test Times, Jacklyn Higgs Jan 2022

Shock Tube And Gas Dynamic Design Considerations And Implementation For Extended Test Times, Jacklyn Higgs

Electronic Theses and Dissertations, 2020-2023

A new shock tube test section has been designed and manufactured for the purpose of increasing the test time and expanding the applications of the shock tube for a multitude of ongoing and future projects. One purpose for the test section extension is to allow for flow visualization of droplets impacted by a shock wave for the interaction of hypersonic vehicles and atmospheric disturbances. Another purpose is to measure behind the incident shock to capture the chemical kinetics for a high-altitude environment and low-pressure, high-temperature space applications. This new test section contains 24 round optical ports for laser spectroscopy for …

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Reporter Chondrocyte Optimization Of Bioinks For Zonal 3d Bioprinting Of Cartilage, Kari Martyniak Jan 2022

Reporter Chondrocyte Optimization Of Bioinks For Zonal 3d Bioprinting Of Cartilage, Kari Martyniak

Electronic Theses and Dissertations, 2020-2023

Osteoarthritis (OA) is the most common form of arthritis, often thought of as a disease of the elderly, but post traumatic OA predominantly impacts younger individuals. Articular cartilage is the tissue that coats the end of your bones in synovial joints. Since cartilage has limited healing capacity, defects, or injuries to it progressively erodes down to the subchondral bone. Unfortunately, current treatment options all have limitations, particularly for younger patients. Cartilage has a specific zonal architecture that is distinguished by the different cell morphologies and arrangements, biochemical composition, and mechanical properties. 3D bioprinting is a tissue engineering technique that involves …

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Prediction And Validation Of Residual Stresses In Additively Manufactured Metal Parts, Jose Mayi Rivas Jan 2022

Prediction And Validation Of Residual Stresses In Additively Manufactured Metal Parts, Jose Mayi Rivas

Electronic Theses and Dissertations, 2020-2023

Selective Laser Melted (SLM) Additively Manufactured (AM) metal parts are of special interest to many industries because their designs can be made arbitrarily complex while still maintaining bulk type mechanical properties. However, the large thermal gradients inherent to the SLM process generate residual stresses (RS) and distortions that are detrimental to the fit, functionality and integrity of parts. Predicting the state of stresses in as-built 3D printed parts is a difficult problem that currently has only been approached with the use of transient thermomechanical Finite Element Models (FEMs). The nonlinearities associated with AM processes are difficult to capture in these …

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Fabrication Of Piezoelectric Field Effect Transistors For Acoustic Signal Detection, Luke Minks Jan 2022

Fabrication Of Piezoelectric Field Effect Transistors For Acoustic Signal Detection, Luke Minks

Electronic Theses and Dissertations, 2020-2023

In this study, a standard bulk FET design is fabricated with a piezoelectric gate, allowing a microwave-frequency voltage signal to be transmitted from a transducer to the transistor via acoustic conduction through the substrate. Using a single polycrystalline aluminum nitride film as the piezoelectric material, microwave-frequency piezoelectric transducers were fabricated in parallel with piezoelectric FETs. These device pairs function by generating high frequency acoustic waves in the substrate via application of AC voltage to the transducers; the transistors then recover these signals by detecting these waves in their gates via the piezoelectric film, reproducing an attenuated version of the original …

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Investigating The Effect Of Cmas Infiltration On Residual Stress Of High Temperature Ceramic Coatings For Turbine Engines Using 3d Confocal Raman Spectroscopy, Zachary Stein Jan 2022

Investigating The Effect Of Cmas Infiltration On Residual Stress Of High Temperature Ceramic Coatings For Turbine Engines Using 3d Confocal Raman Spectroscopy, Zachary Stein

Electronic Theses and Dissertations, 2020-2023

Calcium-magnesium-aluminosilicates (CMAS), such as sand or volcanic ash, are ingested by aircraft jet engines during operation. CMAS then becomes molten while traveling through the combustor of the engine before depositing onto turbine blades within the turbine section of the engine. The molten CMAS melt infiltrates and interacts with the high temperature ceramic coated turbine blades. This infiltration increases coating stiffness and promotes coating phase destabilization, encouraging micro-crack formation and increasing the risk of spallation. Thermomechanical effects from CMAS infiltration were mapped over time with confocal Raman spectroscopy. The residual stresses within infiltrated 7YSZ EB-PVD coatings were captured with microscale resolution. …

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Examining The Relationship Between Six Sigma Failures And The Utilization Of Cost Engineering Approaches, Dennis Tribby Jan 2022

Examining The Relationship Between Six Sigma Failures And The Utilization Of Cost Engineering Approaches, Dennis Tribby

Electronic Theses and Dissertations, 2020-2023

The purpose of the quantitative non-experimental research study is to analyze the relationship between the impact of using cost engineering approaches and the success rate of Six Sigma projects in the manufacturing industry. This study focuses on the relationship between Six Sigma project failures and whether skilled cost engineering professionals, methods or a cost management system was used to ensure that accurate cost data was utilized during the design project's lifecycle. Many companies using Six Sigma and related methodologies for product design have implemented with great success yet there are studies indicating that only 13% of firms reported achieving their …

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Testing The Influence Of Water Depth In Design Of Created Oyster Reef For Living Shoreline Applications, Peter Vien Jan 2022

Testing The Influence Of Water Depth In Design Of Created Oyster Reef For Living Shoreline Applications, Peter Vien

Electronic Theses and Dissertations, 2020-2023

Living shoreline stabilization has become a popular practice in shoreline restoration and bank protection; however, there are still many uncertainties regarding effective site design using living materials. For example, natural wave-breaks may be formed of created reefs, but the optimum water depth for hydrodynamic influence may differ from the preferred depth to ensure organism recruitment. The objective of this research is to understand how water depth relative to the crest of submerged artificial oyster reef structures influences nearshore hydrodynamic processes and sediment transport or retention in nearshore areas. A field study, sited in a microtidal estuary on the Atlantic coast …

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A Deep Learning Approach For Spatiotemporal-Data-Driven Traffic State Estimation, Amr Hatem Ragaa Abdelraouf Jan 2022

A Deep Learning Approach For Spatiotemporal-Data-Driven Traffic State Estimation, Amr Hatem Ragaa Abdelraouf

Electronic Theses and Dissertations, 2020-2023

The past decade witnessed rapid developments in traffic data sensing technologies in the form of roadside detector hardware, vehicle on-board units, and pedestrian wearable devices. The growing magnitude and complexity of the available traffic data has fueled the demand for data-driven models that can handle large scale inputs. In the recent past, deep-learning-powered algorithms have become the state-of-the-art for various data-driven applications. In this research, three applications of deep learning algorithms for traffic state estimation were investigated. Firstly, network-wide traffic parameters estimation was explored. An attention-based multi-encoder-decoder (Att-MED) neural network architecture was proposed and trained to predict freeway traffic speed …

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Studying The Electrostatic Effects On The Dynamics Of Charged Lunar Dust Via Discrete Element Method, Hao Wang Jan 2022

Studying The Electrostatic Effects On The Dynamics Of Charged Lunar Dust Via Discrete Element Method, Hao Wang

Electronic Theses and Dissertations, 2020-2023

Dust problems raise significant concerns in planetary surface exploration. The unusual behavior of the dust particles that surround the vehicle after engine cutoff has the potential to have more of an influence on surface systems than the high velocity lunar rocket plume ejecta in the landing process. A prevailing hypothesis attributes the levitation and transport of dust particles on the surface of airless bodies to the electrostatic effects and electric field. However, there is no accurate model considering the inter-particle electrostatic interactions, especially when the particles are charged by plume. This dissertation aims to understand the behavior of charged lunar …

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Application Of Biologically Activate Carbon For Treatment Of Sulfide-Laden Groundwater, Jessica Cormier Jan 2022

Application Of Biologically Activate Carbon For Treatment Of Sulfide-Laden Groundwater, Jessica Cormier

Electronic Theses and Dissertations, 2020-2023

Small-system water purveyors must overcome many challenges to provide an adequate and safe water supply to its consuming public. This dissertation reports on research related to the application of biologically activated carbon (BAC) media filters for the treatment of well water to remove disinfection by-product (DBP) precursor matter, measured as dissolved organic carbon (DOC), at two treatment plants serving a small community water system. Four research questions were investigated individually in discrete, yet interconnected studies at two water treatment facilities processing groundwater that contained hydrogen-sulfide (~1.2 mg/L) and dissolved organic carbon (~2.0 mg/L). The first study revealed that BAC filters …

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