Engineering Commons^™

Experimental Analysis And Computer Simulation Of A Laboratory-Scale Intermittent Water Supply System, Brian Rivers

Dissertations, Master's Theses and Master's Reports

Intermittent water systems (IWS) are prevalent throughout developing regions of the world. However, few tools exist to predict IWS performance because modeling transient flow is difficult: IWS networks can experience widely fluctuating conditions, ranging from completely empty to completely full (pressurized flow). An experimental IWS, consisting of a 50.75-gallon reservoir, an elevated distribution network, and four outlets was constructed to study the hydraulics of IWS. Three experiments were run on the system that represented two falling-head scenarios and a constant-head scenario. Computer simulation models of the experimental IWS were developed in EPANET 2.2.0 and EPA-SWMM 5.1, which are open-source modeling …

Per- And Polyfluoroalkyl Substances Mitigation From Contaminated Groundwater Using Halophyte And Cow Bone Biochars, Bailey Papes

Dissertations, Master's Theses and Master's Reports

Per- and polyfluoroalkyl substances (PFAS) groundwater contamination is a growing concern for the Brackish Groundwater National Desalination Research Facility. Two of the four wells onsite are contaminated with perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorohexane sulfonic acid (PFHxS). The removal of PFAS by adsorption onto powder activated carbon (PAC) is promising, but the production of PAC is energy intensive and expensive. A potential cost-effective alternative to PAC is biochar. This study quantified the capacities of two halophyte biochars, cow bone biochar and PAC to adsorb PFOA, PFOS, and PFHxS from brackish groundwater. The three biochars were ineffective at …

Wireless Power Transfer In Autonomous Mobile Microgrids, Carl Greene

Dissertations, Master's Theses and Master's Reports

The ability to autonomously dock unmanned ground vehicles plays a key role in mobile micro-grids, where efficient power transfer is paramount. The approach utilized in this work allows for near-field wireless power transfer in remote locations with minimal support. Establishing a micro-grid power system connection autonomously using wireless power eliminates the arduous task of designing a complex, multiple degrees of freedom (MDOF) robotic arm. The work presented in this thesis focuses on both the hardware and software within the micro-grid system. This particular near-field wireless system consists of a primary and secondary set of modules, comprised of Litz wire coils, …

Simulating Groundwater Pollutant Transport For Remediation Design, Antrim County, Michigan, Abilynn Raetz

Dissertations, Master's Theses and Master's Reports

Located in Antrim County, Michigan between the coasts of Torch Lake and Lake Michigan is a hydrocarbon plume that has impacted surrounding residential wells. The plume is comprised of benzene, toluene, ethylbenzene, and xylenes (BTEX) and primarily resides in the shallowest groundwater aquifer. The plume is suspected of having originated from an underground storage container that was removed in 1979. A conceptual model was developed for the site, comprising of a simplified hydrogeological model. Groundwater modeling was performed using Aquaveo's groundwater modeling software (GMS). PEST parameter calibration was performed on the hydraulic conductivity and recharge values using data from surrounding …

Eager Scheduling Of Dependent Instructions, Kurush Kasad

Dissertations, Master's Theses and Master's Reports

Modern superscalar processors are able to potentially issue and execute multiple instructions per cycle. Several techniques over the years have focused on increasing the Instruction Level Parallelism (ILP) that a processor can exploit. However, there are many limitations of ILP that hinder performance, chief of them being the chain of dependencies between instructions that stops instructions from being executed in parallel.

We propose a new micro-architecture design which extends the superscalar pipeline with a data-flow pipeline where the dataflow part identifies immediately dependent instructions and executes them early. The dataflow pipeline is able to identify redundant instructions, track changes in …

An Experimental Study Towards Underwater Propulsion System Using Structure Borne Traveling Waves, Shreyas Suhas Gadekar

Dissertations, Master's Theses and Master's Reports

The method of generating steady-state structure-borne traveling waves underwater in an infinite media creates abundant opportunities in the field of propulsive applications, and they are gaining attention from several researchers. This experimental study provides a framework for harnessing traveling waves in a 1D beam immersed under quiescent water using two force input methods and providing a motion to an object floating on the surface of the water.

In this study, underwater traveling waves are tailored using structural vibrations at five different frequencies in the range of 10Hz to 300Hz. The resulting fluid motion provides a propulsive thrust that moves a …

Permeability, Structural Changes, Flow Regime Transitions In Fuel Cell Catalyst Layers And A Model For Predicting Trapped Saturation For Two-Phase Flow In Porous Media, Karrar Takleef Alofari

Dissertations, Master's Theses and Master's Reports

Proper water management in Proton Exchange Membrane (PEM) fuel cell is important to achieve high performance. Understanding the percolation of the produced water at the cathode catalyst layer (CL) is critical for any robust water management technique. In this study, an ex-situ experimental setup is used to study percolation in the CL at different injection rates and relative humidity (RH) conditions. The results show that increasing the flow rate force the liquid to flow through the bulk of the pores due to the dominant viscous effect. On the other hand, at low injection rates, the capillary becomes dominant and liquid …

Length-Scale-Dependent Stress Relief Mechanisms In High Purity Indium, Fereshteh Mallakpour

Dissertations, Master's Theses and Master's Reports

Lithium-ion batteries are widely used in portable electronics and electric vehicles. However, due to the presence of flammable liquid electrolytes, these devices fail catastrophically when the cell experiences a short circuit. One attractive solution to this problem is a solid-state battery. As the name implies, the flammable liquid electrolyte is replaced by a non-flammable solid-state electrolyte (SSE). The unexpected, yet frequently observed failure mechanism in these devices is the formation and growth of lithium dendrites originating at the interface between the lithium anode and the SSE. As the dendrites grow, device performance degrades. Once the dendrites completely penetrate the SSE, …

Understanding Strength Of Dried Iron Ore Pellets, Victor Claremboux

Dissertations, Master's Theses and Master's Reports

After an extensive literature review, it was found that there was no reliable way for predicting the impact of binders or mixtures of binders on iron ore pellets. This is a challenging problem because iron ore pellets are a complex product of an agglomeration process which is typically controlled only to the extent that is necessary to form a quality product for ironmaking. This work identifies the resistance of a dried pellet to abrasion as a prime variable to record and analyze to understand the influence of combined pellet binders. A consistent method of measuring abrasion resistance is identified and …

The Role Of Inclusion In Climate Vulnerability Assessment And Equitable Adaptation Goals In Small American Municipalities, Elena Lioubimtseva

Open Access Publishing Support Funded Articles

Equity and inclusion considerations are important prerequisites of effective climate adaptation planning, especially at a local scale. This study examines how climate adaptation plans of small American cities and counties consider equity in their climate vulnerability assessments and adaptation planning goals and how consideration of equity in existing adaptation plans relates to the inclusion of diverse categories of stakeholders. Data analysis is based on the content of 23 local climate adaptation plans of small urban and rural municipalities across the United States with populations of less than 300 thousand people. Correlations between conceptualization of vulnerability dimensions, inclusion of 9 categories …

Effect Of Silica Size In Ticl4/Mgcl2-Sio2 Catalysts On Ethylene Polymerization Behaviors, Nattawat Manomaiwajee

Chulalongkorn University Theses and Dissertations (Chula ETD)

At present, the production of polyethylene has a high production volume. The commonly used catalyst for the synthesis of polyethylene is Ziegler-Natta. The development of polymer morphology and efficiency of ethylene polymerization in the petrochemical industry was developed by the addition of silica supports. However, the specific properties of silica have not been widely researched with the Ziegler-Natta catalyst. Therefore, the effect of silica size on the Ziegler-Natta catalyst was studied in this thesis. The study focused on the polymerization of ethylene and the copolymerization of ethylene/1-hexene in slurry process. The silica sizes used as bisupport were varied including 8 …

ประสิทธิภาพตัวกลางดูดซับสำหรับกำจัดสารหนูจากน้ำบาดาลในพื้นที่จังหวัดระยอง, วรรณพศุกร์ สิทธิผล

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีวัตถุประสงค์เพื่อศึกษาประสิทธิภาพตัวกลางดูดซับสำหรับกำจัดสารหนูจากน้ำบาดาล โดยศึกษาตัวกลางดูดซับ 3 กลุ่ม คือ วัสดุโครงข่ายโลหะอินทรีย์ วัสดุที่มีทางการค้า และวัสดุทางการเกษตร โดยถ่านกัมมันต์ทางการค้าชนิดเกล็ด (Granular activated carbon, GAC) ถูกนำมาปรับสภาพด้วยสารปรับสภาพ 2 ชนิด ได้แก่ การเคลือบด้วย Zeolitic idazolate framework และเหล็กไนเตรท ส่วนถ่านมันสำปะหลังถูกปรับสภาพพื้นผิวด้วยเหล็กไนเตรท จากการศึกษาประสิทธิภาพการดูดซับสารหนูเบื้องต้นเพื่อคัดเลือกวัสดุที่มีความเหมาะสมในการนำไปใช้งานในระบบคอลัมน์พบว่า ถ่านกัมมันต์ทางการค้าชนิดเกล็ดที่ปรับสภาพด้วยเหล็กไนเตรท (GAC-120-250Fe) มีความเหมาะสมในการนำไปใช้งานในระบบคอลัมน์เนื่องจากมีความสามารถในการดูดซับสารหนูได้เพียงพอ มีความแข็งแรงของโครงสร้างอนุภาค และมีการชะละลายเหล็กและสารอินทรีย์ละลายน้ำต่ำ ผลการศึกษาจลนพลศาสตร์และไอโซเทอร์มการดูดซับสารหนูของ GAC-120-250Fe พบว่า สอดคล้องกับสมการอันดับสองเทียมและสมการของฟรุนดลิช ตามลำดับ การวิเคราะห์การชะละลายของเหล็กและสารอินทรีย์ละลายน้ำพบว่าค่าทั้งสองมีค่าต่ำกว่ามาตรฐานน้ำบาดาลดื่มได้ ส่วนการศึกษาการดูดซับในระบบคอลัมน์พบว่า การเพิ่มความสูงของชั้นตัวกลางดูดซับส่งผลให้เวลาในการผลิตน้ำจนถึงความเข้มข้นเบรกทรู (Breakthrough) เพิ่มมากขึ้นและเป็นไปตามสมการของโบฮาร์ท-อดัมส์ โดยเส้นกราฟเบรกทรูที่ได้จากการทดลองสอดคล้องกับแบบจำลองของโทมัส ค่าอัตราการใช้ตัวกลางดูดซับ (Usage rate) และค่าเวลาสัมผัส (EBCT) ที่ให้ประสิทธิภาพการดูดซับสารหนูสูงสุดได้แก่ 286.2 มิลลิลิตรต่อกรัม และ 15.7 นาที ตามลำดับ ที่อัตราเร็วการไหลที่ 0.51 เซนติเมตรต่อนาที

Implementing Effective Learning With Ubiquitous Learning Technology During Coronavirus Pandemic, M. Samir Abou El-Seoud, Hosam F. El-Sofany

Computer Science

Ubiquitous computing supports U-learning to develop and implement a new educational environment that provides effective and interactive learning to students wherever they are. This study aims to present a qualitative evaluation for using U-learning instead of traditional education to avoid the spread of the Coronavirus pandemic. The authors introduce a UTAUT (Unified Theory of Acceptance and Use of Technology) model to assess the capability of the given factors that are expected to affect the learners’ intention and behavior for accepting the U-learning technology for full E-learning. The research study shows a promising impact on the use of U-learning apps for …

การกำหนดนโยบายบริหารเพื่อเพิ่มประสิทธิภาพการเตรียมอะไหล่คงคลังกรณีศึกษาโรงงานผลิตกรดอะมิโน, พรพัชร จิระเดชะ

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้นำเสนอนโยบายการบริหารเพื่อเพิ่มประสิทธิภาพในการเตรียมอะไหล่คงคลังกรณีศึกษาโรงงานผลิตกรดอะมิโน ซึ่งมูลค่าอะไหล่คงคลังเฉลี่ยต่อปี มีแนวโน้มเพิ่มขึ้นจาก 8.3 ล้านบาท ปี พ.ศ. 2559 จนถึง 10.5 ล้านบาท ปี พ.ศ. 2564 ซึ่งสวนทางกับมูลค่าการเบิกใช้อะไหล่ที่มีมูลค่าน้อยลง จึงส่งผลให้อัตราหมุนเวียนอะไหล่มีค่าเฉลี่ยต่อปีอยู่ที่ 0.034 และ 0.102 ในปี พ.ศ. 2559 และปี พ.ศ. 2564 ตามลำดับ ซึ่งแสดงให้เห็นว่าอะไหล่ที่ถูกเก็บในคลังมากกว่าความต้องการ ส่งผลให้สูญเสียค่าใช้จ่ายในการเก็บสูง ดังนั้นการเพิ่มประสิทธิภาพในการเตรียมอะไหล่จะถูกพิจารณาการดำเนินงานผ่านนโยบายการตัดสินใจการเก็บอะไหล่ และปริมาณการเก็บคงคลัง โดยเริ่มต้นจากการนำเสนอเมทริกซ์การตัดสินใจการเก็บอะไหล่ ที่ต้องมีการประเมินความวิกฤติอะไหล่ผ่านเมทริกซ์ 1. Part/equipment critical 2. Supplier/lead-time 3. Failure modes and effects criticality analysis และ 4. Decision matrix จากนโยบายการตัดสินใจการเก็บอะไหล่สามารถช่วยตัดสินใจเก็บอะไหล่ที่มีความวิกฤตสูง ส่วนอะไหล่ที่มีความวิกฤตต่ำจะไม่ถูกตัดสินใจเก็บ จากผลการศึกษาพบว่าสามารถลดจำนวนรายการอะไหล่ที่ต้องจัดเก็บลงได้ 40% จากนั้นนำเสนอนโยบายการตัดสินใจปริมาณการเก็บอะไหล่ ด้วยนโยบาย Base stock ใหม่ โดยการพิจารณาโอกาสการเบิกใช้อะไหล่ผ่านการแจกแจงแบบปัวส์ซองแบบสะสม และผลการจำลองด้วยวิธีการมอนติคาร์โลทั้งหมด 30 ครั้ง พบว่ามูลค่าอะไหล่เฉลี่ยลดลง 68% และระดับอะไหล่ลดลง 60% ส่งผลให้มูลค่าคลังเฉลี่ยลดลงจาก 8.7 ล้านเหลือ 2.3 ล้านบาท และอัตราการหมุนเวียนอะไหล่เฉลี่ยเพิ่มขึ้นจาก 0.060 เป็น 0.220 โดยไม่มีอะไหล่ขาดมือ และผลการทดสอบนโยบายกับชุดข้อมูล ปี พ.ศ. 2563 – 2564 พบว่ามูลค่าอะไหล่เฉลี่ยลดลง 24 % และระดับอะไหล่ลดลง 19% โดยไม่มีอะไหล่ขาดมือ

Artificial Solid Electrolyte Interface With Superhalogen-Based Double Antiperovskite Li6os(Bh4)2 Materials For Dentrite-Free And Stable Lithium Metal Batteries, Gazi Mahfujul Alam

Electronic Theses and Dissertations

Lithium (Li) metal is regarded as the most propitious anode material for next-generation battery technologies owing to its incredibly high theoritical capacity (3860 mAh g-1) and the most negative electrochemical equilibrium potential (-3.04 V vs standard hydrogen electrode). However, the practical implementation of Li anode in commercial lithium batteries is severely inhibited by the unstable solid liquid interfaces resulting from the ultrahigh reactivity, which leads to dendrite growth, low coulombic efficiency, extreme volume fluctuation, and even safety concerns. For a stable and efficient lithium anode to build next generation Li metal battery, in this thesis, we have tried to solve …

Sentiment Without Sentiment Analysis: Using The Recommendation Outcome Of Steam Game Reviews As Sentiment Predictor, Anqi Zhang

Electronic Theses and Dissertations

This paper presents and explores a novel way to determine the sentiment of a Steam game review based on the predicted recommendation of the review, testing different regression models on a combination of Term Frequency-Inverse Document Frequency (TF-IDF) and Latent Dirichlet Allocation (LDA) features. A dataset of Steam game reviews extracted from the Programming games genre consisting of 21 games along with other significant features such as the number of helpful likes on the recommendation, number of hours played, and others. Based on the features, they are grouped into three datasets: 1) either having keyword features only, 2) keyword features …

Use Of Human–Computer Interaction Devices And Web 3.0 Skills Among Engineers, Dr. Robbie L. Walker

Walden Dissertations and Doctoral Studies

Despite massive company investments in human–computer interaction devices and software, such as Web 3.0 technologies, engineers are not demonstrating measurable performance and productivity increases. There is a lack of knowledge and understanding related to the motivation of engineers to use Web 3.0 technologies including the semantic web and cloud applications for increased performance. The purpose of this quantitative correlational study was to investigate whether the use of human–computer interaction devices predict Web 3.0 skills among engineers. Solow’s information technology productivity paradox was the theoretical foundation for this study. Convenience sampling was used for a sample of 214 participants from metropolitan …

Ground To Air Testing Of A Fused Optical-Radar Aircraft Detection And Tracking System, Chester V. Dolph, Thomas Lombaerts, Evan Kawamura, Corey Ippolito, Vahram Stepanyan, Khan M. Iftekharuddin, George Szatkowski, Robert G. Mcswain, Chris Morris, Mahyar R. Malekpour

Electrical & Computer Engineering Faculty Publications

Onboard detection and tracking capability are integral to the sensing component in collision avoidance systems needed to safely operate autonomous urban air taxis and small Unmanned Aircraft Systems. Ground-based validation of detection and tracking systems is an important milestone towards the end goal of real-time collision avoidance using onboard sensors and algorithms. In this work, we evaluate three Extended Kalman Filter (EKF) based fusion trackers with radar and vision detection inputs, and compare them with baseline trackers for each sensor type. Performance is assessed using field collected data of ground to air test flights with the sensors co-located on a …

Solute Concentration Effects On Microstructure And The Compressive Strength Of Ice-Templated Sintered Lithium Titanate, Rohan Parai, Ziyang Nie, Raina Hempley, Gary M. Koenig Jr., Dipankar Ghosh

Mechanical & Aerospace Engineering Faculty Publications

This work investigated the role of sucrose and cationic dispersant (1‐hexadecyl)trimethylammonium bromide concentration on ice‐templated sintered lithium titanate microstructure and compressive strength, to enable a comprehensive understanding of composition selection and elucidate processing–microstructure–mechanical property relationships. Sucrose and dispersant concentrations were varied to change total solute concentration in suspensions and viscosity. Dispersant was more effective in reducing viscosity than sucrose; however, their combination had an even greater impact on reducing viscosity. Based on viscosity measurements, a total of 12 suspension compositions were developed, and materials were fabricated at two different freezing front velocity (FFV) regimes. Solute concentration greatly influenced ice‐templated microstructure …

A Review On Heat Flux Measurement Techniques In The Nano And Microscale, Miguel Moreno

Honors Program: Senior Projects (Public)

Heat Flux measurements represent an important step in obtaining an accurate heat transfer profile in many engineering problems. Sensors capable of measuring this quantity have been around for decades, however, the increasing focus in nano and microscale applications in the industry and academia demands more accurate and smaller devices. This paper reviews some of the methods used to develop heat flux meters targeted to nano and microscale, as well as some calibration processes for the same. A combination of Luminescence and non-luminescence methods for direct and indirect measurement of heat flux will be discussed. A glimpse of what the future …

نيوتروسوفيك أوفرسيت ، نيوتروسوفيك أونديرست ، وإزاحة نيوتروسوفيك [Neutrosophic Overset, Neutrosophic Underset, And Neutrosophic Offset], Florentin Smarandache, Riad K Al-Hamido (Translator From English To Arabic)), Khaled Adnan Alabdullah (Translator From English To Arabic)

Branch Mathematics and Statistics Faculty and Staff Publications

تم تعريف Neutrosophic Over-/ Under- / Off-Set and -Logic لأول مرة بواسطة Smarandache في عام 1995 ونشر في عام 2007. وهي مختلفة تمامًا عن المجموعات / المنطق / الاحتمالات الأخرى. قام بتمديد مجموعة العدلات على التوالي إلى Neutrosophic Overset {عندما يكون بعض مكونات neutrosophic> 1} ، Neutrosophic Underset {عندما يكون بعض مكونات neutrosophic <0} ، وإلى إزاحة Neutrosophic {عندما تكون بعض مكونات العدلات خارج الفاصل الزمني [0 ، 1] ، أي بعض مكونات العدلات> 1 ومكونات أخرى نيوتروسوفيك <0}. هذا ليس مفاجئًا فيما يتعلق بالمجموعة / المنطق الغامض الكلاسيكي ، أو المجموعة / المنطق الغامض الحدسي ، أو الاحتمال الكلاسيكي / غير الدقيق ، حيث لا يُسمح بالقيم خارج الفاصل الزمني [0 ، 1] ، نظرًا لأن عالمنا الحقيقي به العديد من الأمثلة و تطبيقات المكونات الزائدة / السفلية / البعيدة عن العدلات

Neutrosophic Over-/Under-/Off-Set and -Logic were defined for the first time by Smarandache in 1995 and published in 2007. They are totally different from other sets/logics/probabilities. He extended the neutrosophic set respectively to Neutrosophic Overset {when some neutrosophic component is > 1}, Neutrosophic Underset {when …

Collected Papers (On Neutrosophics Theory And Applications), Volume Xii, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

This twelfth volume of Collected Papers includes 86 papers comprising 976 pages on Neutrosophic Theory and Applications, published between 2013-2021 in the international journal and book series NSS by the author alone or in collaboration with the following 112 co-authors (alphabetically ordered) from 21 countries.

Developing Reactive Distributed Aerial Robotics Platforms For Real-Time Contaminant Mapping, Joshua Ashley

Theses and Dissertations--Electrical and Computer Engineering

The focus of this research is to design a sensor data aggregation system and centralized sensor-driven trajectory planning algorithm for fixed-wing aircraft to optimally assist atmospheric simulators in mapping the local environment in real-time. The proposed application of this work is to be used in the event of a hazardous contaminant leak into the atmosphere as a fleet of sensing unmanned aerial vehicles (UAVs) could provide valuable information for evacuation measures. The data aggregation system was designed using a state-of-the-art networking protocol and radio with DigiMesh and a process/data management system in the ROS2 DDS. This system was tested to …

Nebraska Summary: 1231 John Deere 6r 120 Diesel Infinitely Variable Transmission, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Optimizing The Fabrication Process For Next Generation Nano-Textured Solar Cells With High Conversion Efficiency Using Industrially Viable Solar Cell Processes, Orlagh Murphy

Masters

The need for photovoltaic (PV) cells with high conversion efficiency and low surface reflectance has been on the rise. With this in mind, the fabrication process of PV cells has been investigated with interest in the surface etching phase in order to reduce surface reflectance using nanotexturing. The purpose of this thesis is to investigate how to improve the etching phase by optimising the key parameters for an atmospheric dry etch (ADE) with different processes to determine which can aid in reducing surface reflectance.

To obtain a process which provides a low surface reflectance, parameters in the etching phase are …

Dielectric State Variables As Qualitative Indicators Of Moisture Absorption-Caused Mechanical Property Degradation In Gfrp Composite Structures, Partha Pratim Das, Vamsee Vadlamudi, Rassel Raihan

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

Fiber reinforced polymer (FRP) composites are being used in numerous fields owing to their intrinsic strength to weight ratio and various design benefits. However, these materials are prone to environmental aging, particularly moisture absorption. In essence, absorbed moisture infiltrates the polymer matrix and induces changes in the polymer network through chain scission, plasticization, and other bonding interactions. This causes irreversible damages to the material and significantly decreases mechanical strength. In this study, Broadband Dielectric Spectroscopy (BbDS) has been used to identify the absorption mechanisms in glass fiber reinforced polymer (GFRP) composites by detecting the related polarization mechanisms. Here, results show …

Dielectric Analysis To Predict Moisture Absorption In Structural Composites: A Data-Driven Approach, Partha Pratim Das, Monjur Morshed Rabby, Vamsee Vadlamudi, Rassel Raihan

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

Due to continual exposure to moist environment, environmental degradation is a major threat to structural composites throughout their service life. Impedance Spectroscopy (IS)/Broadband Dielectric Spectroscopy (BbDS) is a reliable nondestructive method that has been used in polymer industries for dielectric characterization of material. While moisture absorption causes irreversible changes in the polymer matrix composites, it also alters the electrical properties of the system which is detectable using BbDS. Since the physics that drives the change in electrical characteristics is driven by the modifications imposed by water molecules (whether free or bound), both events can be linked. A dielectric spectrum over …

Coupled Effects In Dielectric And Thermal Properties Of Polymer Matrix Composite Structures Due To Moisture Absorption, Partha Pratim Das, Monjur Morshed Rabby, Vamsee Vadlamudi, Kenneth Reifsnider, Rassel Raihan

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

Fiber reinforced polymer (FRP) composites are being used in number of fields including aerospace, marine, sports, medical, power sectors, etc. due to their lightweight nature while retaining high mechanical performance in terms of high specific strength, stiffness, and great fatigue properties. However, the applicability of these materials is restricted by their stability up to a certain temperature (i.e. glass transition temperature) and environmental degradation (i.e. moisture, UV light, etc.). Moisture ingression greatly reduces their mechanical properties altering material structure by causing polymer plasticization, chain scission and fiber-polymer interface deterioration. These changes instantaneously affect the thermal properties of the materials which …

The Effect Of Plasma Treatment On The Cure Behavior Of Out-Of-Life Prepregs And An Investigation Of The Mechanical Properties Of Composite Parts Manufactured From Plasma-Treated Prepregs, Monjur Morshed Rabby, Partha Pratim Das, Minhazur Rahman, Vamsee Vadlamudi, Rassel Raihan

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

Many industries, including aircraft, automobiles, and marine, are using prepreg (pre-impregnated fibers and a partially cured polymer matrix) to manufacture composite parts to achieve optimum fiber and resin volume ratio and part repeatability. Since prepregs have a short out oflife (i.e., the maximum storing time allowed at room temperature), they must be stored in refrigerators at low temperatures, which, if not maintained, have an unfavorable influence on the intended quality of the final product. For the present study, glass/epoxy prepregs (expired out-life) were plasmatreated before being used to make the composite part to compensate for the room temperature aging effect. …

Model-Based Cognitive Communications For Low-Power Wireless Networks, Indika Sanjeewa Abeywickrama Dhanapala

Theses

Our world is increasingly being instrumented with low-power wireless networks that deliver data for diverse application domains such as energy management, health and well-being, security, and other Internet of Things services. As these wireless networks operate in the unlicensed radio spectrum while co-existing with various other communication networks, their communication reliability and energy efficiency are affected by the radio environment. Because of this vulnerability to radio interference, low-power wireless networks may be unable to deliver their application requirements and be inefficiently consuming energy, functioning as a low-dependability network. The situation is exacerbated in indoor environments such as office and residential …