Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

2024

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 7231 - 7260 of 9238

Full-Text Articles in Engineering

L∞ Bounds For Transient Growth In Repetitive And Iterative Learning Control Systems, Douglas A. Bristow, John R. Singler Jan 2024

L∞ Bounds For Transient Growth In Repetitive And Iterative Learning Control Systems, Douglas A. Bristow, John R. Singler

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper revisits the problem of large transient growth in Iterative Learning Control (ILC) and Repetitive Process Control (RPC) systems. In ILC and RPC problems a process is repeated iteratively, with new control calculations occurring in between each iteration. Large transient growth refers to the propensity of some control algorithms to grow error exponentially before eventually converging. While robust monotonic convergence algorithms (in which monotonic convergence is guaranteed usually in exchange for a small loss in performance) have largely eliminated the concern for large transient growth in ILC, similar results cannot always be obtained in RPC. The emergence of additive …

Go to article

Effect Of Bioactive Borate Glass On Printability And Physical Properties Of Hydrogels, Fateme Fayyazbakhsh, Mehedi H. Tusar, Yue-Wern Huang, Ming C. Leu Jan 2024

Effect Of Bioactive Borate Glass On Printability And Physical Properties Of Hydrogels, Fateme Fayyazbakhsh, Mehedi H. Tusar, Yue-Wern Huang, Ming C. Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Hydrogels are a key component in bioinks and biomaterial inks for bioprinting due to their biocompatibility and printability at room temperature. The research described in the present paper contributes to the advancement of bioprinting by studying the effect of bioactive borate glass (BBG) incorporated into hydrogels on printability and physical properties. In this study, we fabricated 3D-printed hydrogel scaffolds using gelatin and alginate hydrogel mixture incorporated with various amounts of BBG, a bio ceramic rich in therapeutic ions including boron, calcium, copper, and zinc. We investigated the effect of incorporating BBG on the density, viscosity, physical interactions, chemical structure, and …

Go to article

An Evaluation Of Methods For Assessing Robot Kinematic Model Accuracy In The Presence Of Noise, Mitchell R. Woodside, Patrick Bazzoli, Philip A. Olubodun, J. Adam Nisbett, Guixiu Qiao, Douglas A. Bristow Jan 2024

An Evaluation Of Methods For Assessing Robot Kinematic Model Accuracy In The Presence Of Noise, Mitchell R. Woodside, Patrick Bazzoli, Philip A. Olubodun, J. Adam Nisbett, Guixiu Qiao, Douglas A. Bristow

Mechanical and Aerospace Engineering Faculty Research & Creative Works

While there are many works developing methods for modeling and calibrating robot kinematics, assessing the accuracy of those models has received little attention. However, accuracy assessment is critically important for applications where the robot must operate with absolute accuracy over a large region of workspace, such as in robotic machining. When the model of such a system is well calibrated, the remaining deterministic error can be quite complex, owing to complicated gearing errors, deformations, and quasi-static thermal changes. Locating the largest deterministic error requires an exploration over the workspace, but assessing the largest error is complicated by repeatability error and …

Go to article

Impact Of Aging On Pim And Dc Resistance Of Fabric-Over-Foam Metallic Contacts, Kalkidan W. Anjajo, Seunghun Ryu, Shengxuan Xia, Gracie Boyer, Yuchu He, Haicheng Zhou, Hanfeng Wang, Jonghyun Park, Chulsoon Hwang Jan 2024

Impact Of Aging On Pim And Dc Resistance Of Fabric-Over-Foam Metallic Contacts, Kalkidan W. Anjajo, Seunghun Ryu, Shengxuan Xia, Gracie Boyer, Yuchu He, Haicheng Zhou, Hanfeng Wang, Jonghyun Park, Chulsoon Hwang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper the impact of aging on the level of passive intermodulation (PIM) and DC resistance of fabric-over-foam metallic contacts is presented. These contacts are widely used to maintain metallic connections between modules and chassis in electronic devices. The PIM caused by the loose metallic contact of these materials mainly affects a receiver's RF sensitivity in mobile devices. This aging test under elevated temperature and relative humidity conditions offers an experiment-based approach with respect to various metallic contact cases. Energy dispersive spectroscopy and scanning electron microscopy are used to characterize the change in material composition and the contact surface …

Go to article

Mixing Measurement On Hydrogen Jet By Libs Under Various Injection Strategies, Youngmin Ki, Jungho Justin Kim, Seong Young Lee, Joonsik Hwang, Choongsik Bae Jan 2024

Mixing Measurement On Hydrogen Jet By Libs Under Various Injection Strategies, Youngmin Ki, Jungho Justin Kim, Seong Young Lee, Joonsik Hwang, Choongsik Bae

Michigan Tech Publications

Favorable fuel properties of hydrogen for combustion system opens a new avenue to achieve deep decarbonization in transportation sector. Meanwhile, various technical challenges including low volumetric energy density, nitrogen oxide emissions, and backfire impede successful implementation of hydrogen in combustion engines. To overcome those issues, stratified charge combustion (SCC) is considered to optimize engine performance and emissions. As direct injection approach is utilized in SCC mode, ensuring quality of air-fuel mixing in combustion chamber is crucial. This study aims to understand hydrogen mixing behavior by quantitative measurement on equivalence ratio using laser-induced breakdown spectroscopy (LIBS). This measurement has been conducted …

Go to article

Photogrammetry-Based Method For Measuring Volume Changes Of Soil Specimens During Critical Phases Of Triaxial Testing, Sara Fayek, Xiong Zhang, Pingxin Xia Jan 2024

Photogrammetry-Based Method For Measuring Volume Changes Of Soil Specimens During Critical Phases Of Triaxial Testing, Sara Fayek, Xiong Zhang, Pingxin Xia

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Triaxial tests has been routinely used to measure the stress–strain relationship for geomaterials. During triaxial testing, many sources of errors that cannot be completely avoided but are often ignored or approximated using empirical equations. This paper presents a systematic investigation of soil volume change, volume strain nonuniformity, and cross-sectional calculation along the specimen during triaxial testing using a photogrammetry-based method. Consolidated drained triaxial tests were performed in which two parallel measurements were taken: (1) relative volume using the conventional triaxial testing and (2) absolute volume using the photogrammetry-based method. The difference in the observed volume and void ratio measurements between …

Go to article

Scshm Benchmark Study On Bridge In-Service Structural Monitoring, Maria Pina Limongelli, Doug Thomson, Sreenivas Alampalli, Aftab Mufti, Thomas Schumacher, Luca Martinelli, Othmane Lasri, Harry Shenton, Genda Chen, Mohammad Noori, Farnaz Raeisi, Ahmed Silik, Ji Dang, Ray Hoemsen Jan 2024

Scshm Benchmark Study On Bridge In-Service Structural Monitoring, Maria Pina Limongelli, Doug Thomson, Sreenivas Alampalli, Aftab Mufti, Thomas Schumacher, Luca Martinelli, Othmane Lasri, Harry Shenton, Genda Chen, Mohammad Noori, Farnaz Raeisi, Ahmed Silik, Ji Dang, Ray Hoemsen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The mission of the Society of Civil Structural Health Monitoring (SCSHM, previously known as ISHMII) is to advance the understanding and application of structural monitoring methodologies for the management of civil infrastructure systems. To enable comparative and contrasting studies of various monitoring issues and technologies, the SCSHM Committee on Data-Enhanced Infrastructures Management (DEIMC) identified the need for benchmark problems in the areas of bridge and building structural monitoring. This article reports and briefly discusses the first benchmark study on in-service structural monitoring of bridges that was developed in collaboration with the University of Manitoba, and presents the structure details, study …

Go to article

A Hybrid Algorithm To Dual Sparse Sampling Measurement In Time-Resolved Electromagnetic Near-Field Scanning, Yanming Zhang, Steven Gao, Lijun Jiang Jan 2024

A Hybrid Algorithm To Dual Sparse Sampling Measurement In Time-Resolved Electromagnetic Near-Field Scanning, Yanming Zhang, Steven Gao, Lijun Jiang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Time-resolved electromagnetic near-field scanning is vital for antenna measurement and addressing complex electromagnetic interference and compatibility issues. However, the swift acquisition of high-resolution spatiotemporal data remains challenging due to physical constraints, such as moving the probe position and allowing sufficient time for sampling. This paper introduces a novel hybrid approach that combines Kriging for sparse spatial measurement, compressed sensing (CS) for sparse temporal sampling, and dynamic mode decomposition (DMD) for a comprehensive analysis of dual-sparse sampling electromagnetic near-field data. CS optimizes sparse sampling in the time domain, capitalizing on the inherent sparsity within electromagnetic radiated signals, resulting in reliable representation …

Go to article

A Data-Driven Approach To Time-Domain Electromagnetic Modeling Based On Dynamic Mode Decomposition, Yanming Zhang, Steven Gao, Lijun Jiang Jan 2024

A Data-Driven Approach To Time-Domain Electromagnetic Modeling Based On Dynamic Mode Decomposition, Yanming Zhang, Steven Gao, Lijun Jiang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This paper presents a data-driven methodology that utilizes Dynamic Mode Decomposition (DMD) for the time-domain (TD) electromagnetic (EM) modeling of microwave devices. As an unsupervised machine learning technique, DMD leverages a limited set of unlabeled spatio-temporal electromagnetic (EM) data to determine DMD eigenvalues and eigenmodes. Then, the obtained DMD model reconstructs the dynamics as a series of exponential terms based on linear assumptions. The effectiveness of this approach is demonstrated through the TD EM modeling of photonic crystal waveguides. Comparative analysis with the finite-difference time-domain (FDTD) method shows that the DMD model not only achieves precise modeling but also facilitates …

Go to article

Novel Re-Crosslinkable Preformed Particle Gels (Rppg) For Parent- And Infill-Well-Fracture Interactions Mitigation, Xiaojing Ge, Adel Alotibi, Ahmed Al-Hlaichi, Yanbo Liu, Tao Song, Junchen Liu, Baojun Bai, Thomas P. Schuman Jan 2024

Novel Re-Crosslinkable Preformed Particle Gels (Rppg) For Parent- And Infill-Well-Fracture Interactions Mitigation, Xiaojing Ge, Adel Alotibi, Ahmed Al-Hlaichi, Yanbo Liu, Tao Song, Junchen Liu, Baojun Bai, Thomas P. Schuman

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Hydraulic fracturing treatments in unconventional infill (or "child") wells can be significantly affected by depletion from existing parent-well, resulting in asymmetrical fracture growth. These issues may lead to excessive load-water production, proppant deposition, casing deformation in the parent well, and unbalanced stimulation of infill wells. To mitigate these effects, various strategies have been proposed, including the use of far-field diverters in child wells and repressurization of parent wells. Additionally, an increasingly popular strategy involves injecting near-wellbore diverters to temporarily plug entry points into the parent wellbores during frac operations on infill wells. To achieve better application, a novel low-cost, self-degradable, …

Go to article

An Unsupervised Learning Framework For Determining The Excitation Coefficients Using Near-Field Antenna Measurements, Yanming Zhang, Peifeng Ma, Steven Gao, Lijun Jiang Jan 2024

An Unsupervised Learning Framework For Determining The Excitation Coefficients Using Near-Field Antenna Measurements, Yanming Zhang, Peifeng Ma, Steven Gao, Lijun Jiang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This article presents a novel unsupervised learning framework based on multiscale dynamic mode decomposition for determining the excitation coefficients of antennas using time-domain near-field measurements. The proposed framework integrates temporal multiscale analysis to extract a joint distribution of frequency, damping factors, and spatial modes, enabling precise extraction of excitation frequencies, rising/falling edges, and phases without labeled data. We validate the effectiveness of the proposed approach through two examples involving on-off keying modulation and a phase-shift dipole antenna. It is found that the proposed method performs well in handling nonstationary excitation signals and proves particularly advantageous for calibrating tunable antenna systems. …

Go to article

Descriptive Statistical Analysis Of Experimental Data For Wettability Alteration With Smart Water Flooding In Carbonate Reservoirs, Muhammad Ali Buriro, Mingzhen Wei, Baojun Bai, Ya Yao Jan 2024

Descriptive Statistical Analysis Of Experimental Data For Wettability Alteration With Smart Water Flooding In Carbonate Reservoirs, Muhammad Ali Buriro, Mingzhen Wei, Baojun Bai, Ya Yao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Smart water flooding is a promising eco-friendly method for enhancing oil recovery in carbonate reservoirs. the optimal salinity and ionic composition of the injected water play a critical role in the success of this method. This study advances the field by employing machine learning and data analytics to streamline the determination of these critical parameters, which are traditionally reliant on time-intensive laboratory work. the primary objectives are to utilize data analytics to examine how smart water flooding influences wettability modification, identify key parameter ranges that notably alter the contact angle, and formulate guidelines and screening criteria for successful lab design. …

Go to article

Electrostatic Sorting Of Lunar Regolith Simulants For Sustainable Resource Utilization: Modeling And Characterization Of Particle Size Distribution, Abdullah Al Moinee, Peter Bachle, Kyle Newport, William Schonberg, David Bayless, Jeffrey Smith, Daoru Han, Fateme Rezaei Jan 2024

Electrostatic Sorting Of Lunar Regolith Simulants For Sustainable Resource Utilization: Modeling And Characterization Of Particle Size Distribution, Abdullah Al Moinee, Peter Bachle, Kyle Newport, William Schonberg, David Bayless, Jeffrey Smith, Daoru Han, Fateme Rezaei

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In pursuit of sustainable resource utilization on the Moon, this paper delves into modeling and characterization of particle size distribution (PSD) of lunar regolith simulants in an electrostatic system. A prototype electrostatic sieve was built and tested with four sample simulants mirroring properties of lunar mare and highland regolith. An alternating four-phase (90 degrees, 180 degrees, 270 degrees, 360 degrees) traveling square-wave was utilized for particle-directed transport to model the diverse trajectories of the particles. Numerically, we scrutinized how the distribution functions of the particles are manifested as the electrostatic field propagates, with a focus on three distinct particle ranges …

Go to article

Intelligent Millimeter-Wave System For Human Activity Monitoring For Telemedicine, Abdullah K. Alhazmi, Mubarak A. Alanazi, Awwad H. Alshehry, Saleh M. Alshahry, Jennifer Jaszek, Cameron Djukic, Anna Brown, Kurt Jackson, Vamsy P. Chodavarapu Jan 2024

Intelligent Millimeter-Wave System For Human Activity Monitoring For Telemedicine, Abdullah K. Alhazmi, Mubarak A. Alanazi, Awwad H. Alshehry, Saleh M. Alshahry, Jennifer Jaszek, Cameron Djukic, Anna Brown, Kurt Jackson, Vamsy P. Chodavarapu

Electrical and Computer Engineering Faculty Publications

Telemedicine has the potential to improve access and delivery of healthcare to diverse and aging populations. Recent advances in technology allow for remote monitoring of physiological measures such as heart rate, oxygen saturation, blood glucose, and blood pressure. However, the ability to accurately detect falls and monitor physical activity remotely without invading privacy or remembering to wear a costly device remains an ongoing concern. Our proposed system utilizes a millimeter-wave (mmwave) radar sensor (IWR6843ISK-ODS) connected to an NVIDIA Jetson Nano board for continuous monitoring of human activity. We developed a PointNet neural network for real-time human activity monitoring that can …

Go to article

Exponential Fusion Of Interpolated Frames Network (Efif-Net): Advancing Multi-Frame Image Super-Resolution With Convolutional Neural Networks, Hamed Elwarfalli, Dylan Flaute, Russell C. Hardie Jan 2024

Exponential Fusion Of Interpolated Frames Network (Efif-Net): Advancing Multi-Frame Image Super-Resolution With Convolutional Neural Networks, Hamed Elwarfalli, Dylan Flaute, Russell C. Hardie

Electrical and Computer Engineering Faculty Publications

Convolutional neural networks (CNNs) have become instrumental in advancing multi-frame image super-resolution (SR), a technique that merges multiple low-resolution images of the same scene into a high-resolution image. In this paper, a novel deep learning multi-frame SR algorithm is introduced. The proposed CNN model, named Exponential Fusion of Interpolated Frames Network (EFIF-Net), seamlessly integrates fusion and restoration within an end-to-end network. Key features of the new EFIF-Net include a custom exponentially weighted fusion (EWF) layer for image fusion and a modification of the Residual Channel Attention Network for restoration to deblur the fused image. Input frames are registered with subpixel …

Go to article

Pleated Plasma Membrane Complex In Spermatids Of The Western Siren, Siren Nettingi (Caudata: Sirenidae), S.E. Trauth Jan 2024

Pleated Plasma Membrane Complex In Spermatids Of The Western Siren, Siren Nettingi (Caudata: Sirenidae), S.E. Trauth

Journal of the Arkansas Academy of Science

I investigated the pleated plasma membrane complex of linear folds and biflagellar entities in developing spermatids of the Western Siren, Siren nettingi. My primary goal was to reveal the ultrastructural morphology of these distinctive cellular folds (usually 8 in number) as they support the flagellar formation of biflagellated sperm found in this salamander and in other members in the family Sirenidae. My results reveal that the biflagellar components (2 sets of axonemes, undulating membranes, and axial fibers), termed biflagellar complex, develop between folds or are attached onto these folds. The folds themselves are transitory and do not directly contribute to …

Go to article

แบบจำลองการจัดลำดับความสำคัญของความเสี่ยงของยูสเซอร์สตอรีสำหรับการจัดลำดับความสำคัญโดยใช้ตรรกะคลุมเครือ, เปรม สุนทรภาส Jan 2024

แบบจำลองการจัดลำดับความสำคัญของความเสี่ยงของยูสเซอร์สตอรีสำหรับการจัดลำดับความสำคัญโดยใช้ตรรกะคลุมเครือ, เปรม สุนทรภาส

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในกระบวนการพัฒนาซอฟต์แวร์แบบแอไจล์ ยูสเซอร์สตอรีเป็นองค์ประกอบสำคัญที่สะท้อนความต้องการของผู้ใช้ แต่หากยูสเซอร์สตอรีมีคุณภาพไม่เพียงพอ อาจก่อให้เกิดความเสี่ยงที่ส่งผลกระทบต่อความสำเร็จของโครงการอย่างมีนัยสำคัญ ดังนั้นงานวิจัยนี้จึงนำเสนอแบบจำลองการจัดลำดับความสำคัญของความเสี่ยงของยูสเซอร์สตอรีโดยใช้ตรรกะคลุมเครือ เพื่อช่วยให้สามารถจัดการกับความไม่แน่นอนในการตัดสินใจได้อย่างมีประสิทธิภาพ โดยเริ่มจากการนิยามความเสี่ยงของยูสเซอร์สตอรีจำนวน 12 ประเภท พร้อมทั้งกำหนดเกณฑ์การประเมินใน 2 ด้าน ได้แก่ ด้านความพยายามในการบริหารจัดการ และด้านข้อจำกัดในการบริหารจัดการ จากนั้นจึงประยุกต์ใช้ตรรกะคลุมเครือร่วมกับตัวแปรภาษาและฟังก์ชันความเป็นสมาชิกในการคำนวณค่าคะแนนความเสี่ยง และจัดลำดับความสำคัญผ่านแบบจำลองที่พัฒนาขึ้น ผลการประเมินการใช้งานแบบจำลองกับผู้มีประสบการณ์ในโครงการแอไจล์พบว่า แบบจำลองสามารถช่วยในการจำแนกความเสี่ยงได้อย่างเหมาะสมและมีความสอดคล้องกับความคิดเห็นของผู้ประเมิน ซึ่งผลการประเมินสะท้อนถึงความสมเหตุสมผลของแบบจำลองและความสามารถในการประยุกต์ใช้จริง ดังนั้นงานวิจัยนี้จึงเป็นประโยชน์ต่อทีมพัฒนาในการประเมินและจัดลำดับความเสี่ยงของยูสเซอร์สตอรีได้อย่างเป็นระบบ และเพิ่มประสิทธิภาพในการบริหารความเสี่ยงในโครงการพัฒนาซอฟต์แวร์แบบแอไจล์ได้ดียิ่งขึ้น

Go to article

การวิเคราะห์เชิงเศรษฐศาสตร์เทคโนโลยีของแนวทางการผลิตไฮโดรเจนสำหรับกระบวนการเปลี่ยนคาร์บอนไดออกไซด์เป็นเมทานอลและเปลี่ยนเมทานอลเป็นโอลิฟินส์, กันตภณ มานิมนต์ Jan 2024

การวิเคราะห์เชิงเศรษฐศาสตร์เทคโนโลยีของแนวทางการผลิตไฮโดรเจนสำหรับกระบวนการเปลี่ยนคาร์บอนไดออกไซด์เป็นเมทานอลและเปลี่ยนเมทานอลเป็นโอลิฟินส์, กันตภณ มานิมนต์

Chulalongkorn University Theses and Dissertations (Chula ETD)

อุตสาหกรรมปิโตรเคมีเป็นหนึ่งในแหล่งปล่อยก๊าซคาร์บอนไดออกไซด์ (CO2) คิดเป็นสัดส่วนใหญ่ของโลก โดยเฉพาะจากกระบวนการแครกเกอร์แนฟทาด้วยไอน้ำ (Steam Naphtha Cracking) การดักจับและใช้ประโยชน์จากคาร์บอน (Carbon Capture and Utilization: CCU) จึงเป็นแนวทางที่ได้รับความสนใจเพื่อลดการปล่อย CO2 หนึ่งในกระบวนการที่มีศักยภาพคือ ไฮโดรเจนของคาร์บอนไดออกไซด์ (Hydrogenation of CO2) เพื่อผลิตเมทานอล ซึ่งเมทานอลสามารถนำไปใช้เป็นวัตถุดิบในกระบวนการแปรรูปเป็นโอเลฟินส์ (Methanol-to-Olefins: MTO) ได้อีกด้วย งานวิจัยนี้ศึกษาแนวทางการผลิตไฮโดรเจนซึ่งเป็นสารตั้งต้นที่สำคัญของกระบวนการ โดยศึกษา3 ประเภท ได้แก่ ไฮโดรเจนสีเทา (Grey Hydrogen) จากกระบวนการ Steam Methane Reforming (SMR), Autothermal Reforming (ATR) และ SMR ร่วมกับ ATR, ไฮโดรเจนสีน้ำเงิน (Blue Hydrogen) และไฮโดรเจนสีเขียว (Green Hydrogen) จากกระบวนการอิเล็กโทรไลซิส (AEL) โดยทำการจำลองกระบวนการด้วย Aspen Plus และประเมินค่าเชิงเศรษฐศาสตร์ด้วยค่า LCOH (Levelized Cost of Hydrogen) ผลการศึกษาแสดงให้เห็นว่า ไฮโดรเจนสีเทาแบบ SMR มี LCOH ต่ำที่สุดที่ 1.03 USD/kg H2 แต่ปล่อย CO2 สูงสุด 13.44 kg CO2/kg H2 ขณะที่ไฮโดรเจนสีน้ำเงินให้การลด CO2 ที่ดีขึ้น 6.85 kg CO2/kg H2 ด้วยต้นทุนที่เพิ่มขึ้น 1.16 USD/kg H2 ส่วนไฮโดรเจนสีเขียวปล่อย CO2 ต่ำที่สุดแต่มีต้นทุนสูงสุดที่ 4.38 USD/kg H2 ดังนั้นการเลือกใช้แหล่งผลิตไฮโดรเจนที่เหมาะสมจึงมีผลโดยตรงต่อประสิทธิภาพและความยั่งยืนของกระบวนการผลิตเมทานอลและโอเลฟินส์ในอนาคต

Go to article

Temperature Control In The Steam Methane Reformer Using Model Predictive Control Based On A Neural Network Model, Rasiq Dipta Alkindi Jan 2024

Temperature Control In The Steam Methane Reformer Using Model Predictive Control Based On A Neural Network Model, Rasiq Dipta Alkindi

Chulalongkorn University Theses and Dissertations (Chula ETD)

Hydrogen is a critical energy vector, and magnetic heating reactors represent a promising production technology where current-induced magnetization raises system temperature. Due to the nonlinear and complex thermal dynamics, this study applies a hybrid Echo State Network (ESN) and Long Short-Term Memory (LSTM) model to capture system behavior, combining ESN’s nonlinear dynamic identification with LSTM’s ability to learn long-term dependencies. Hyperparameters were optimized for best performance at 30 reservoir nodes, 0.5 spectral radius, 0.9 connectivity, batch size 4, 50 LSTM units, and 60 epochs. The ESN-LSTM models with 3-input and 4-input feature sets were tested on three winding coil geometries …

Go to article

Ecgconvt : A Hybrid Cnn And Vision Transformer Model For 12-Lead Ecg Images Classification, Mudassar Khalid Jan 2024

Ecgconvt : A Hybrid Cnn And Vision Transformer Model For 12-Lead Ecg Images Classification, Mudassar Khalid

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cardiovascular diseases (CVDs) are the most common cause of human deaths globally, and they can be controlled by early diagnosis and accurate classification of the electrocardiograms. The Electrocardiogram, commonly known as an ECG, is a very affordable technique to know about the health of the heart from 12 different angles by using 12-Leads to capture the heart's electrical activity. A hybrid deep learning model is proposed in this study to classify the different heart diseases. The deep learning model is composed of a CNN(Xception) to capture all the local feature-maps of the images and a vision transformer (ViT) to study …

Go to article

Investigation Of Molecular Interactions In Electrocatalysis Using Atomic Force Microscopy, Parivat Phiphatbunyabhorn Jan 2024

Investigation Of Molecular Interactions In Electrocatalysis Using Atomic Force Microscopy, Parivat Phiphatbunyabhorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Electrocatalysis at the nanoscale is fundamentally governed by molecular interactions, but these processes remain poorly understood due to their difficulty to directly investigate and their complex nature. In this study, atomic force microscopy (AFM)-based force spectroscopy is employed to investigate interfacial forces and reactivity in two representative systems: the electrochemical deterioration and healing of Au nanothin films on n-type silicon and the electrocatalytic reduction of MEA-CO2 adduct on Cu electrocatalysts. In the Au nanothin film system, observing that surface degradation is mediated by anionic cluster interactions and modulated by intrinsic band bending and surface energy effects. Remarkably, 20-nm Au films …

Go to article

Development Of A New Green Infrastructure By Using Biochar Amended Topsoil For On-Site Stormwater Runoff Treatment, Ayesha Sadia Jan 2024

Development Of A New Green Infrastructure By Using Biochar Amended Topsoil For On-Site Stormwater Runoff Treatment, Ayesha Sadia

College of Graduate Studies: Theses & Dissertations

This Research Project aimed to design, build, operate and maintain, and monitor a new green infrastructure (GI) using biochar-amended topsoil for on-site stormwater runoff treatment in urban areas. The project involved evaluating the removal efficiencies of pollutants from stormwater runoff such as total suspended solid (TSS), nutrients including nitrogen and phosphorous, heavy metals including lead (Pb), zinc (Zn) and copper (Cu) and oil and grease etc. from the media of biochar amended topsoil. In this Project, a full-scale Field Test Site with a total area of 500 and 1 ft depth was built to on-site treat stormwater runoff from a …

Go to article

Enhancing The Bandwidth And Radiation Characteristics Of Size-Reduced Antennas, Jack P. Nemec Jan 2024

Enhancing The Bandwidth And Radiation Characteristics Of Size-Reduced Antennas, Jack P. Nemec

College of Graduate Studies: Theses & Dissertations

Electrically small antennas are researched heavily throughout electromagnetic literature due to their practicality. Antennas need to be able to fit into small places such as cell phones. However, the reduction of antenna size comes at a cost in decreasing the impedance bandwidth and radiation efficiency of the antenna. This research aims to find solutions to having sized-reduced antennas while enhancing both the impedance bandwidth and radiation characteristics of the antenna. First, the size reduction of a dual-element dipole is analyzed. Dual-element dipoles are known to have impedance bandwidth enhancing properties along with the ability to have different radiation modes. Next, …

Go to article

Nanosecond Pulsed Electric Fields Increase Antibiotic Susceptibility In Methicillin-Resistant Staphylococcus Aureus, Alexandra E. Chittams-Miles, Areej Malik, Erin B. Purcell, Claudia Muratori Jan 2024

Nanosecond Pulsed Electric Fields Increase Antibiotic Susceptibility In Methicillin-Resistant Staphylococcus Aureus, Alexandra E. Chittams-Miles, Areej Malik, Erin B. Purcell, Claudia Muratori

Bioelectrics Publications

Staphylococcus aureus is the leading cause of skin and soft-tissue infections (SSTIs). SSTIs caused by bacteria resistant to antimicrobials, such as methicillin-resistant S. aureus (MRSA), are increasing in incidence and have led to higher rates of hospitalization. In this study, we measured MRSA inactivation by nanosecond pulsed electric fields (nsPEF), a promising new cell ablation technology. Our results show that treatment with 120 pulses of 600 ns duration (28 kV/cm, 1 Hz), caused modest inactivation, indicating cellular damage. We anticipated that the perturbation created by nsPEF could increase antibiotic efficacy if nsPEF were applied as a co-treatment. To test this …

Go to article

Dihydroethidium-Derived Fluorescence In Electrically Stressed Cells Indicates Intracellular Microenvironment Modifications Independent Of Ros, Esin B. Sözer, Iurii Semenov, P. Thomas Vernier Jan 2024

Dihydroethidium-Derived Fluorescence In Electrically Stressed Cells Indicates Intracellular Microenvironment Modifications Independent Of Ros, Esin B. Sözer, Iurii Semenov, P. Thomas Vernier

Bioelectrics Publications

Intracellular reactive oxygen species (ROS) generation is widely suggested as a trigger for biological consequences of electric field exposures, such as those in electroporation applications. ROS are linked with membrane barrier function degradation, genetic damage, and complex events like immunological cell death. Dihydroethidium (DHE) is commonly used to monitor ROS in cells. DHE is linked to intracellular ROS by a primary oxidation product, Ethidium (Eth+), that shows increased fluorescence upon binding to polynucleotides. We observed changes in DHE-derived fluorescence in Chinese hamster ovary (CHO) cells post 300-ns electric pulse exposures, comparing them to tert-butyl-hydroperoxide (t-BHP) induced oxidative stress. …

Go to article

Mouralherwaqh Coastal Wetland Road Crossing Da'luk, Natalie Mendez Jan 2024

Mouralherwaqh Coastal Wetland Road Crossing Da'luk, Natalie Mendez

Cal Poly Humboldt theses and projects

The integration of Indigenous and Western science plays an essential role in Tribally led collaborations for land management. This process of woven sciences is rooted in reciprocal relations and partnerships guided by Tribal Nations. Our cohort was invited by Wiyot Tribal Representatives to investigate a culvert located within the wetlands of Mouralherwaqh— a parcel of land reacquired by the Wiyot Tribe in 2022. This document seeks to share our experience and analysis as part of the Wiyot Tribe’s broader journey in navigating ecocultural restoration projects within Mouralherwaqh. The four community interests we investigated for the wetland crossing included a resized …

Go to article

Comparative Analysis Of Ac Coupled And Dc Coupled Microgrids: Analyzing Electrical Performances And Economics, Sanjeev Kumar Jan 2024

Comparative Analysis Of Ac Coupled And Dc Coupled Microgrids: Analyzing Electrical Performances And Economics, Sanjeev Kumar

Cal Poly Humboldt theses and projects

This study compares the electrical performance and economics of DC-coupled and AC-coupled community microgrid configurations through simulation and financial modeling of the Redwood Coast Airport Microgrid (RCAM), which integrates 2.2 MW of solar PV and 2.2 MW of battery storage. Unified load flow, short circuit, transient stability (including load impact), and efficiency studies using ETAP & SAM software tools demonstrate that the DC-coupled configuration is preferred based on efficiency, while both configurations exhibit equivalent performance with respect to selected power quality metrics. The DC setup exhibits 11% higher overall efficiency than AC coupling in converting solar energy to grid exports. …

Go to article

Synergistic Effects Of Nanosecond Pulsed Plasma And Electric Field On Inactivation Of Pancreatic Cancer Cells In Vitro, Edwin A. Oshin, Zobia Minhas, Ruben M. L. Colunga Biancatelli, John D. Catravas, Richard Heller, Siqi Guo, Chunqi Jiang Jan 2024

Synergistic Effects Of Nanosecond Pulsed Plasma And Electric Field On Inactivation Of Pancreatic Cancer Cells In Vitro, Edwin A. Oshin, Zobia Minhas, Ruben M. L. Colunga Biancatelli, John D. Catravas, Richard Heller, Siqi Guo, Chunqi Jiang

Bioelectrics Publications

Nanosecond pulsed atmospheric pressure plasma jets (ns-APPJs) produce reactive plasma species, including charged particles and reactive oxygen and nitrogen species (RONS), which can induce oxidative stress in biological cells. Nanosecond pulsed electric field (nsPEF) has also been found to cause permeabilization of cell membranes and induce apoptosis or cell death. Combining the treatment of ns-APPJ and nsPEF may enhance the effectiveness of cancer cell inactivation with only moderate doses of both treatments. Employing ns-APPJ powered by 9 kV, 200 ns pulses at 2 kHz and 60-nsPEF of 50 kV/cm at 1 Hz, the synergistic effects on pancreatic cancer cells (Pan02) …

Go to article

Unveiling Travel Patterns With The Next-Generation Passive Mobile Origin And Destination (Od) Data From The National Household Travel Survey, Muthumari Anbumani, Srinivas S. Pulugurtha Jan 2024

Unveiling Travel Patterns With The Next-Generation Passive Mobile Origin And Destination (Od) Data From The National Household Travel Survey, Muthumari Anbumani, Srinivas S. Pulugurtha

Kentucky Transportation Center Presentations

No abstract provided.

Go to article

Extrinsic Calibration Of 3d Lidar Using Sphere Targets And Target-Centered Gps, Xinyu Cao, Sean Brennan Jan 2024

Extrinsic Calibration Of 3d Lidar Using Sphere Targets And Target-Centered Gps, Xinyu Cao, Sean Brennan

Kentucky Transportation Center Presentations

No abstract provided.

Go to article

First Prev Next Last