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

Digital Commons Network™

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

Mechanical Engineering

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1261 - 1290 of 13113

Full-Text Articles in Entire DC Network

Material Models For Simulation Of Steel Hot Rolling Process Using Experimentally Determined Properties At Elevated Temperatures And Strain Rates, Siva Sai Krishna Dasari Jan 2024

Material Models For Simulation Of Steel Hot Rolling Process Using Experimentally Determined Properties At Elevated Temperatures And Strain Rates, Siva Sai Krishna Dasari

Doctoral Dissertations

"Hot rolling is one of the most important and complex process that includes large material deformation, different contact conditions, complex geometries and different temperature gradients along with micro structural changes such as viscoplasticity, dynamic recrystallization, and static softening. In the present work, the viscoplasticity, damage evolution, static softening and void closure of alloyed metal during hot rolling process was numerically investigated. GleebleTM hot compression and double hit tests were performed to provide experimental stress-strain curves at recrystallization temperatures and at different strain rates. Johnson-Cook viscoplastic model was calibrated using experimental stress-strain curves. Static softening model was developed at varying …


Methodology For Parameter Determination For Simulation Software, Aaron Flood Jan 2024

Methodology For Parameter Determination For Simulation Software, Aaron Flood

Doctoral Dissertations

"This research aims to present a methodology for optimizing input datasets to increase the accuracy of mathematical models and accelerate their application to engineering problems. To accomplish this goal, this work focused on the application of mathematical models to metal additive manufacturing (AM), specifically the thermal history of laser directed energy deposition (DED) of aluminum alloys. The initial steps of this body of work were to develop a mathematical model that is capable of simulating the metal AM process and applying it to the laser DED of aluminum. It was validated using the well characterized material Ti-64 and shown to …


Kinetic Modeling And Simulations Of Plasma-Surface-Dust Interactions For Lunar Exploration, David Clifford Lund Jan 2024

Kinetic Modeling And Simulations Of Plasma-Surface-Dust Interactions For Lunar Exploration, David Clifford Lund

Doctoral Dissertations

"Due to the recent relevance of NASA’s focus on lunar missions, a better understanding of the lunar plasma-surface-dust environment is vital for their success. The lunar surface, devoid of an atmosphere and a global magnetic field, is directly exposed to solar radiation and solar wind plasma. This exposure leads to the electrical charging of the lunar surface due to the bombardment of solar wind plasma and the emission/collection of photoelectrons. Therefore, this research developed accurate and efficient computational models of plasma-surface-dust interactions and extend a legacy simulation code, namely the Immersed-Finite-Element Particle-in-Cell (IFE-PIC), to a parallel version: Parallel Immersed-Finite-Element Particle-in-Cell …


A Simulation Model Analysis In The Us-Mexico Border, Carlo A. Zorola, Hiram Moya, Aditya Akundi Jan 2024

A Simulation Model Analysis In The Us-Mexico Border, Carlo A. Zorola, Hiram Moya, Aditya Akundi

Manufacturing & Industrial Engineering Faculty Publications

Supply Chain (SC) is the flow of goods or services between supply and demand points. New or innovative strategies in SC have been researched and developed to deal with disruptive events, such as COVID-19, hurricanes, geopolitical, and even climate change. These challenges create supply imbalances, logistical challenges, and policy restrictions for transborder commerce. The DHS has implemented the Free and Secure Trade (FAST) program in both the US-Mexico and US-Canada border. These lanes are dedicated queues for commercial vehicles. In 2022, the government of Nuevo León, México, opened a dedicated lane just for Tesla´s northbound commercial traffic. There has been …


Deepwhalenet: A Climate Change-Aware Fft-Based Neural Network For Underwater Passive Acoustic Monitoring, Nicholas Ryan Rasmussen Jan 2024

Deepwhalenet: A Climate Change-Aware Fft-Based Neural Network For Underwater Passive Acoustic Monitoring, Nicholas Ryan Rasmussen

Dissertations and Theses

In the face of escalating climate threats, the conservation of whale species has become increasingly critical. Traditional acoustic monitoring methods, burdened by extensive pre-processing and post-processing, need more adaptability and efficiency for effective marine mammal surveillance. This study introduces DeepWhaleNet, a novel deep-learning framework tailored for Underwater Passive Acoustic Monitoring (UPAM). DeepWhaleNet is designed to streamline whale detection by directly analyzing raw log-power spectrograms, thus extracting essential acoustic features to conserve these endangered species. The framework employs an extensive short-time Fourier transform (STFT) for input processing and a customized ResNet-18 architecture for classification, distinguishing whale vocalizations from ambient noise and …


Human Arm Stiffness Estimation Method Developed For Overground Physical Interaction Experiments: Experimental Validation And Perspectives For Future Applications, Tarani Kanth Kamma Jan 2024

Human Arm Stiffness Estimation Method Developed For Overground Physical Interaction Experiments: Experimental Validation And Perspectives For Future Applications, Tarani Kanth Kamma

Masters Theses

"To build a physically interactive robot for overground applications, it is crucial to first understand the biomechanics of humans underlying overground physical human-robot interaction (pHRI) tasks. Estimating human arm stiffness during overground interactive tasks is a promising first step toward this goal. For this, an arm stiffness estimation technique was developed in our previous works that consider the unique challenges involving overground pHRI, such as the need to estimate the arm stiffness from a short duration of data with fewer repetitions. In this work, our stiffness estimation method is further validated with a passive spring setup with known stiffness values, …


A Pade-Eno Flux Reconstruction For High-Speed Flows, Blake Martin Jan 2024

A Pade-Eno Flux Reconstruction For High-Speed Flows, Blake Martin

Browse all Theses and Dissertations

The development of high order numerical schemes has been instrumental in advancing computational fluid dynamics (CFD), particularly for applications requiring high resolution of discontinuities and complex flow phenomena prevalent in high-speed flows. This thesis introduces the Pade-ENO scheme, a high-order method that integrates Essentially Non-Oscillatory (ENO) techniques with compact Pade stencils to achieve superior accuracy, up to 7th order, while maintaining stability in harsh environments. The scheme’s performance is evaluated through benchmark tests, including the advection equation, Burgers’ equation, and the Euler equations. For high Mach number flows, such as the sod shock tube the Pade-ENO method demonstrates its ability …


Strategies To Mitigate Efflorescence In Walls Constructed Using Clays Bricks; A Review Article, Marwa Abdulkareem. Anber, Soran Abdulrahman Ahmad, Naros Rahman Mahmoud, Kawan Fuoad. Kayani, Mohammed Ali Abdulrehman Jan 2024

Strategies To Mitigate Efflorescence In Walls Constructed Using Clays Bricks; A Review Article, Marwa Abdulkareem. Anber, Soran Abdulrahman Ahmad, Naros Rahman Mahmoud, Kawan Fuoad. Kayani, Mohammed Ali Abdulrehman

Al-Esraa University College Journal for Engineering Sciences

The construction of buildings, especially residential housing for communities, is a significant industry on a global scale. Masonry units such as bricks, blocks, and stones are often utilized materials. Bricks are highly regarded because to their widespread availability, cost-effectiveness, and excellent insulating capabilities. Nevertheless, the presence of efflorescence presents a difficulty in the construction of brick walls. Efflorescence refers to the process in which salts move to the outer layer of the brick, resulting in the formation of white deposits and negatively impacting its visual appeal. Efflorescence is caused by various circumstances, such as the existence of salts in bricks, …


Fretting Corrosion Wear Of Titanium-Based Alloy (Ti-6al-4v) In 0.9 Wt.% Nacl Solution, Chen-En Lu, Wen-Ken Li, Hung-Hua Sheu, Jeou-Long Lee, Hung-Bin Lee Jan 2024

Fretting Corrosion Wear Of Titanium-Based Alloy (Ti-6al-4v) In 0.9 Wt.% Nacl Solution, Chen-En Lu, Wen-Ken Li, Hung-Hua Sheu, Jeou-Long Lee, Hung-Bin Lee

Journal of Marine Science and Technology–Taiwan

In this study, a high precision fretting tribo-corrosion tester used to analyze the wear and corrosion behavior of Ti alloys in a fretting motion condition. The tester, operated in a ball-on-plate mode, was employed in the fretting corrosion study of metallic bio-materials (Ti and Ti-6Al-4V) under different loads (0 and 10 N), electrolytes (0.9 wt% NaCl and SBF) and fixed displacement frequency (1 Hz). Using profilometer, optical microscope in the experimental analysis and three-body mechanism in the theoretical analysis, the fretting corrosion performances of these bio-medical metals, such as velocity accommodation characteristics, friction, wear, and scratch profile were examined in …


A New-Type Deep Learning Model Based On Shapley Regulation For Containerized Freight Index Prediction, Yen-Chang Shih, Ming-Shue Lin, Taih-Cherng Lirn, Jih-Gau Juang Jan 2024

A New-Type Deep Learning Model Based On Shapley Regulation For Containerized Freight Index Prediction, Yen-Chang Shih, Ming-Shue Lin, Taih-Cherng Lirn, Jih-Gau Juang

Journal of Marine Science and Technology–Taiwan

In this study, we have crafted an innovative methodology that represents a groundbreaking synthesis of deep learning techniques with cooperative game theory. In this study, we use the accuracy of data prediction by different LSTM models as a measurement index and assign different LSTM models corresponding weights through the Shapley value calculation method to construct a more accurate predictive analysis model. We use this improved Shapley regulation model to calibrate a long short-term memory (LSTM) neural network by using historical freight data to predict the China Container Freight Index (CCFI), the leading export container freight index commonly used in China. …


Applicability Of Reducing Valve Timing Overlap For Diesel Engines Under High Exhaust Back Pressure, Chien-Cheng Chen, Yuan-Liang Jeng, Shun-Chang Yen Jan 2024

Applicability Of Reducing Valve Timing Overlap For Diesel Engines Under High Exhaust Back Pressure, Chien-Cheng Chen, Yuan-Liang Jeng, Shun-Chang Yen

Journal of Marine Science and Technology–Taiwan

The exhaust back pressure of diesel engines becomes increasing higher nowadays. As an example, the De-NOx system and DE-SOx system necessitated by the increasingly stringent emission standards, would result in increased exhaust back pressure for those diesel engines adopting such systems. Some ships adopt underwater exhaust system to save space on the working deck and to reduce noise and air pollution, while the hydrostatic pressure under water level has made the exhaust back pressure of diesel engines getting much higher. Under high exhaust back pressure, to keep discharging exhaust unhindered and operating smoothly for diesel engine, it often results in …


Elimination Of Noise In A Ship Cabin Using Multi-Layered Acoustic Boards: An Apso And Sa Approach, Min-Chie Chiu, Ho-Chih Cheng Jan 2024

Elimination Of Noise In A Ship Cabin Using Multi-Layered Acoustic Boards: An Apso And Sa Approach, Min-Chie Chiu, Ho-Chih Cheng

Journal of Marine Science and Technology–Taiwan

A high level of noise, combined with pure tones, is often encountered in ship's cabins, leading to severe psychological and physiological issues for the crew. To address this problem, an indoor noise abatement solution becomes necessary that utilizes efficient acoustic boards integrated with resonators, positioned along the inner walls of the cabin. However, the thickness of the acoustic boards must be strictly limited due to maintenance and operational considerations. This limitation results in insufficient sound absorption capabilities and a restricted range of tuned frequencies, as the resonating frequency of a standard Helmholtz resonator is closely tied to its cavity. A …


Numerical Study On The Aerodynamic Performance Of Four Flettner Rotors By Varying Distance And Spin Ratio, Janghoon Seo, Dong-Woo Park Jan 2024

Numerical Study On The Aerodynamic Performance Of Four Flettner Rotors By Varying Distance And Spin Ratio, Janghoon Seo, Dong-Woo Park

Journal of Marine Science and Technology–Taiwan

The Flettner rotor is a wind-assisted propulsion system applied in eco-friendly ship to reduce greenhouse gas emissions. As the requirements of international regulations on greenhouse gas emissions become increasingly strict, multiple Flettner rotors are being applied, necessitating the evaluation of their performance with varying design parameters. The present study focuses on the aerodynamic performances of four Flettner rotors with variable design parameters of distance and spin ratio. Distances and spin ratios, including relative spin ratios, are considered. The drag and lift coefficients and lift-to-drag ratio of Flettner rotors are determined using Computational Fluid Dynamics (CFD), and the associated flow fields …


Underwater Image Enhancement Algorithm For Dual Color Spaces, Xingsheng Shen, Yalin Song, Shichang Li, Xiaoshu Hu Jan 2024

Underwater Image Enhancement Algorithm For Dual Color Spaces, Xingsheng Shen, Yalin Song, Shichang Li, Xiaoshu Hu

Journal of Marine Science and Technology–Taiwan

Targeting issues related to low contrast, blurring, and loss of detail prevalent in underwater image enhancement algorithms, we propose a dual-color space multiscale residual network (DMR-SCNet) based on SCNet. First, we introduce the HSV color space feature extraction module, which aims to optimize the color representation and saturation of underwater images. Subsequently, we propose the RGB color space denoising module, which focuses on repairing the content and structure of underwater images to enhance their clarity and visual quality. Finally, by designing the residual attention (RAB) module, we aim to further refine the detailed representation and feature extraction of underwater images. …


A Novel Identity Authentication Mechanism For Unmanned Maritime Vessels Communication Based On Mitre Att&Ck Framework, Junxian He, Shih-Hao Chang Jan 2024

A Novel Identity Authentication Mechanism For Unmanned Maritime Vessels Communication Based On Mitre Att&Ck Framework, Junxian He, Shih-Hao Chang

Journal of Marine Science and Technology–Taiwan

With the development of the smart shipping industry, unmanned vessel technology is rapidly evolving, accompanied by a demand for robust Internet of Things (IoT) communication security practices. Key communication technologies for the operation of unmanned vessels include external vessel communication. One crucial aspect is the verification of the identities of the parties involved in these communication systems, as this ensures secure and trusted interactions between unmanned vessels and port management authorities. Identity authentication plays a vital role in ensuring the secure communication of unmanned vessels.This paper aims to analyze potential risks related to identity authentication technology in unmanned vessel communication …


Corrigendum To “Applicability Of Reducing Valve Timing Overlap For Diesel Engines Under High Exhaust Back Pressure” Jan 2024

Corrigendum To “Applicability Of Reducing Valve Timing Overlap For Diesel Engines Under High Exhaust Back Pressure”

Journal of Marine Science and Technology–Taiwan

No abstract provided.


Distribution And Population Structure Of Corallivorous Drupella Snails In The Coral Reefs Of Kenting In Taiwan, Chih-Jui Tan, Dun-Ru Kang, Li-Lian Liu Jan 2024

Distribution And Population Structure Of Corallivorous Drupella Snails In The Coral Reefs Of Kenting In Taiwan, Chih-Jui Tan, Dun-Ru Kang, Li-Lian Liu

Journal of Marine Science and Technology–Taiwan

The corallivorous Drupella snails are common predators of living hard corals in the Indo-Pacific Ocean, and they can significantly threaten coral reef ecosystems when outbreaks occur. In Taiwan, a Drupella outbreak, which resulted in the dramatic decline of Acropora and Montipora corals, was reported in Penghu in 2002 – 2009. However, the Drupella species involved was not identified, and no further research has been conducted. To obtain current knowledge on the predation pressure of corallivorous snails on hard corals, we investigated benthic communities and the distribution and population structure of Drupella snails in the coral reefs of Kenting, Taiwan. The …


Evaluating The Connectivity Reliability Of The Seaborne Transportation Network Using Uncertainty Theory, Tianshou Liu, Haiyang Bian, Lin Feng, Chenyang Fan, Chaojun Ding, Grifoll Manel, Hongxiang Feng Jan 2024

Evaluating The Connectivity Reliability Of The Seaborne Transportation Network Using Uncertainty Theory, Tianshou Liu, Haiyang Bian, Lin Feng, Chenyang Fan, Chaojun Ding, Grifoll Manel, Hongxiang Feng

Journal of Marine Science and Technology–Taiwan

The shipping network serves as the backbone of international trade. However, due to unstable geopolitical conditions, unexpected events have occurred frequently in recent years that have impacted the global shipping supply chain, and this has placed enormous pressure and had adverse effects on seaborne transportation. To measure the reliability of the global shipping network under unexpected events, we abstract the global shipping network into a small world network using uncertainty theory. A method is proposed for selecting (i) the optimal reliable path and (ii) the optimal reliable path with a maximum measurement under different confidence intervals. Our approach is then …


Mechanical Property Analysis And Three-Dimensional Reverse Reconstruction Based On Corrosion Pit Characteristics Of Strong Corrosion Steel Plate, Qiujun Ning, Xiaosong Lu, Jiawei Lu Jan 2024

Mechanical Property Analysis And Three-Dimensional Reverse Reconstruction Based On Corrosion Pit Characteristics Of Strong Corrosion Steel Plate, Qiujun Ning, Xiaosong Lu, Jiawei Lu

Journal of Marine Science and Technology–Taiwan

To investigate the strong corrosion effect of 36% industrial hydrochloric acid on Q370 steel for bridges at room temperature. The surface morphology variations of the Q370 steel for bridges with corrosion time were measured and analyzed using a three-dimensional non-contact scanning profilometer. Subsequently, the standard monotonic tensile test was carried out to obtain the load-displacement curve and analyze the mechanical properties of the heavily corroded steel. Moreover, the constitutive model parameters of the heavily corroded steel were optimized. Furthermore, the heavily corroded steel model base on the actual corroded surface morphology was established, employing three-dimensional reverse reconstruction technology and finite …


Sea Ice Identification And Risk Assessment For Navigation In Ice Regions Based On Shipboard Camera Images, Tsung-Hsuan Hsieh, Xuan Lu, Shengzheng Wang, Wei Liu, Jianan Luo Jan 2024

Sea Ice Identification And Risk Assessment For Navigation In Ice Regions Based On Shipboard Camera Images, Tsung-Hsuan Hsieh, Xuan Lu, Shengzheng Wang, Wei Liu, Jianan Luo

Journal of Marine Science and Technology–Taiwan

In order to guarantee the safe navigation of vessels in icy regions and effectively capture sea ice risk information surrounding ships, this study introduces a sea ice identification and risk assessment process utilizing shipboard camera images. Firstly, based on the distribution characteristics of sea area, a hierarchical region segmentation algorithm is proposed to precisely remove interference factors and extract the region of interest. Then, a multivariate K-means clustering algorithm is proposed to classify sea ice classes based on various characteristics, including spatial similarity, sea ice area, sea ice thickness, gray scale, and other multivariate information. Finally, a method for small …


Optimization On Container Drayage Scheduling In Stochastic Time-Dependent Network, Qi Xu, Jie Huang, Xingyue Chen, Rui Cheng, Xiangyu Yin, Zhongzhen Yang Jan 2024

Optimization On Container Drayage Scheduling In Stochastic Time-Dependent Network, Qi Xu, Jie Huang, Xingyue Chen, Rui Cheng, Xiangyu Yin, Zhongzhen Yang

Journal of Marine Science and Technology–Taiwan

To ensure a reliable operation of container drayage transport system, this paper investigates the drayage scheduling problem in a stochastic time-dependent network. Based on the theory of the robust optimization, a mathematical model considering the attributes of “synchronized operation of multi machines” is built with the aim of minimization of the schedule delay in the whole system. A Simulated Annealing algorithm with Embedded Heuristics (SAEH) is designed for model solution. Comparisons between the results from the robust optimization and traditional expected value approach, and the results from the SAEH and CPLEX are conducted. Based on that, the effectiveness of our …


Offshore Vertical Axis Wind-Photovoltaic Power Plants: Development And Case Study, Victor V. Cheboxarov, Pavel N. Kuznetsov, Shun-Han Yang, Shiu-Wu Chau Jan 2024

Offshore Vertical Axis Wind-Photovoltaic Power Plants: Development And Case Study, Victor V. Cheboxarov, Pavel N. Kuznetsov, Shun-Han Yang, Shiu-Wu Chau

Journal of Marine Science and Technology–Taiwan

This paper examines the potential for the development and implementation of hybrid wind-solar power plants utilizing large-scale offshore vertical-axis wind turbines. The proposed solution aims to increase energy production and reliability through the integration of photovoltaic modules directly into the wind turbine structure. Schematics of photovoltaic modules on the upper annular surface of the respective wind turbine are considered. The operation of the hybrid power plant is described. Equations to estimate the power characteristics of the plant are given. The case study analyzes the potential energy production of a hybrid marine power plant with a diameter of 200 m at …


Harvest By Autoflocculation, Biomass, And Carotenoid Production In Sequential Batch Culture Of Haematococcus Pluvialis Under High Ionic Strength And Macroelements Content, J. Galán-González, I. Quintero-Zapata, M Elías-Santos, L.J. Galán-Wong, U.J. López-Chuken, C Guajardo-Barbosa, J.C Beltrán-Rocha Jan 2024

Harvest By Autoflocculation, Biomass, And Carotenoid Production In Sequential Batch Culture Of Haematococcus Pluvialis Under High Ionic Strength And Macroelements Content, J. Galán-González, I. Quintero-Zapata, M Elías-Santos, L.J. Galán-Wong, U.J. López-Chuken, C Guajardo-Barbosa, J.C Beltrán-Rocha

Journal of Marine Science and Technology–Taiwan

Haematococcus pluvialis is a microalga with significant potential due to its capacity to produce carotenoids with antioxidant and nutraceutical benefits. However, the cost of harvesting this microalga, constituting over 30% of total expenses in large-scale production, is a major concern. Efficient flocculation, aiding in cell separation from the culture medium, is crucial to address this issue. The study contrasted Bold’s Basal Medium (BBM) with Lopez-Chuken & Young nutrient solution (LC-Y). The heightened salt content in LC-Y plays a crucial role in fostering saline stress, which is essential for evaluating H. pluvialis flocculation, biomass yield, and carotenoid production. To assess stability …


Research Progress On Ship Trajectory Prediction In Marine Transportation, Xiangen Bai, Kai Ye, Xiaofeng Xu Jan 2024

Research Progress On Ship Trajectory Prediction In Marine Transportation, Xiangen Bai, Kai Ye, Xiaofeng Xu

Journal of Marine Science and Technology–Taiwan

The prediction of ship navigation trajectories is crucial for ensuring maritime navigation safety and forecasting risk. In recent years, extensive research has been conducted on the prediction of ship navigation trajectories at home and abroad, and some results have been achieved. At present, most research on ship navigation trajectory prediction relies heavily on automatic identification system (AIS) data and the historical trajectories of ships. This study first reviews the research background and current situation of ship navigation trajectory prediction. Second, it provides an overview of ship navigation trajectory prediction, with an emphasis on sorting out and elaborating on artificial intelligence …


Numerical Investigations On Particle Collection And Discharge Of Rounded Rectangle Aquaculture Tank In Dual-Diagonal-Inlet Layout, Xiaozhong Ren, Shupeng Du, Hangfei Liu, Xianying Shi, Meng Li, Xian Wang, Suping Liu Jan 2024

Numerical Investigations On Particle Collection And Discharge Of Rounded Rectangle Aquaculture Tank In Dual-Diagonal-Inlet Layout, Xiaozhong Ren, Shupeng Du, Hangfei Liu, Xianying Shi, Meng Li, Xian Wang, Suping Liu

Journal of Marine Science and Technology–Taiwan

To improve the space utilization rate of aquaculture tanks in aquaculture facilities and investigate the effect of the length-width ratio parameter (abbr. L/W, with L being the length of the tank and W being its width) on the particle collection and discharge characteristics of the rounded rectangle aquaculture tank with diagonal double inlet pipes. The study simulates the particle discharge procedure of the tank using a solidliquid two-phase numerical model (discrete phase model and RNG k-ε turbulence model adopted). The validity of the numerical model was confirmed through physical experiments. The simulation results for two jet condition indicate that when …


Simulation Of Wave Propagation In Granular Particles Using A Discrete Element Model, Syed Tahmid Hussan Jan 2024

Simulation Of Wave Propagation In Granular Particles Using A Discrete Element Model, Syed Tahmid Hussan

College of Graduate Studies: Theses & Dissertations

The understanding of Bender Element mechanism and utilization of Particle Flow Code (PFC) to simulate the seismic wave behavior is important to test the dynamic behavior of soil particles. Both discrete and finite element methods can be used to simulate wave behavior. However, Discrete Element Method (DEM) is mostly suitable, as the micro scaled soil particle cannot be fully considered as continuous specimen like a piece of rod or aluminum. Recently DEM has been widely used to study mechanical properties of soils at particle level considering the particles as balls. This study represents a comparative analysis of Voigt and Best …


The Importance Of Cryptography In Cloud Computing, Saja Alaam Talib Jan 2024

The Importance Of Cryptography In Cloud Computing, Saja Alaam Talib

Al-Esraa University College Journal for Engineering Sciences

Cloud computing has grown as a widely accepted concept simultaneously, as the alarms for the security of data and information. This paper seeks to establish the comprehensive roles of cryptography in tackling these issues in the Cloud environment. The study begins with the historical background of cryptography and then moves on to analyze trends in information technology before discussing on the challenges to security in cloud computing. The goal of its publication is to highlight the importance of using cryptographic technologies for the protection of information confidentiality, its integrity and compliance. The combination of literature review and the case study …


Nonlinear Hydrodynamic Modeling And Control Of Wave Energy Converters, Tania Demonte Gonzalez Jan 2024

Nonlinear Hydrodynamic Modeling And Control Of Wave Energy Converters, Tania Demonte Gonzalez

Dissertations, Master's Theses and Master's Reports

The growing urgency to transition towards carbon-neutral energy sources has sparked significant interest in diversifying energy portfolios by incorporating renewable energies, including the untapped potential of wave energy. This dissertation sets its objectives in advancing wave energy converter (WEC) technologies by focusing on developing and validating a nonlinear modeling technique and designing control strategies to maximize energy extraction and enhance WEC efficiency. At the heart of this research is the derivation and validation of an algebraic nonlinear Froude-Krylov forces model. Building on this foundational model, a robust nonlinear sliding mode controller and a nonlinear model predictive controller are designed to …


Modelling Of The Viscoelastic Relaxation Of A Stowed Telescope Starshade, Rahul Raghu Jan 2024

Modelling Of The Viscoelastic Relaxation Of A Stowed Telescope Starshade, Rahul Raghu

Graduate Thesis and Dissertation 2023-2024

The Habitable Worlds Telescope Starshade is an occulting disk that orbits in tandem with a telescope that occludes and diffuses the light from stars to observe the relatively dim exoplanets in orbit around them. It achieves this in part with tailored petals that diffuse light to soften the light from the star. Due to the relative sizes of the star and the planet, NASA considers the shape stability of the Starshade's petals to be a Key Technology Gap. The Starshade is developed to be a deployable composite structure that folds on itself to fit within modern rockets. Due to the …


Mechanics Of Pure Bending And Eccentric Buckling In High-Strain Composite Structures, Jimesh D. Bhagatji, Oleksandr G. Kravchenko, Sharanabasaweshwara Asundi Jan 2024

Mechanics Of Pure Bending And Eccentric Buckling In High-Strain Composite Structures, Jimesh D. Bhagatji, Oleksandr G. Kravchenko, Sharanabasaweshwara Asundi

Mechanical & Aerospace Engineering Faculty Publications

To maximize the capabilities of nano- and micro-class satellites, which are limited by their size, weight, and power, advancements in deployable mechanisms with a high deployable surface area to packaging volume ratio are necessary. Without progress in understanding the mechanics of high-strain materials and structures, the development of compact deployable mechanisms for this class of satellites would be difficult. This paper presents fabrication, experimental testing, and progressive failure modeling to study the deformation of an ultra-thin composite beam. The research study examines the deformation modes of a post-deployed boom under repetitive pure bending loads using a four-point bending setup and …