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2024

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Articles 8581 - 8610 of 9232

Full-Text Articles in Engineering

Takt Time Reduction Of Genset Assembly Line Using Process Optimization And Lean Manufacturing Tools, Ninad Joshi Jan 2024

Takt Time Reduction Of Genset Assembly Line Using Process Optimization And Lean Manufacturing Tools, Ninad Joshi

All Graduate Theses, Dissertations, and Other Capstone Projects

With rapid developments in the field of AI and data centers, there is a soaring demand for backup power and due to this, genset manufacturers are compelled to increase their throughput and reduce lead times. This study focuses on incorporating process optimization and lean tools for lowering the overall takt time by reducing the cycle time of the generator assembly process of Line 1 at Rolls Royce Solutions America Inc. The eventual goal is to increase the throughput from 6 generators per day to 7 per day. The paper follows a step-by-step methodology starting from the problem statement and uses …


Comparative Study Of Robotic And Manual Welding In A Low Volume-High Mix Manufacturing Environment: Case Study Of Jr Test 2, Pooma Pragna Mysore Jan 2024

Comparative Study Of Robotic And Manual Welding In A Low Volume-High Mix Manufacturing Environment: Case Study Of Jr Test 2, Pooma Pragna Mysore

All Graduate Theses, Dissertations, and Other Capstone Projects

A comparative study of robotic and manual welding in a low volume high mix manufacturing environment focusing on a truck body part named the JR Test 2 to see if there is a benefit of incorporating robotic welding into the production line. By utilizing predetermined time studies such as Methods Time Measurement 1(MTM-1) and Maynard’s Operation Sequence Technique (MOST) in conjunction with actual welding time and motion study to see which method of time study can be used to extrapolate the times of production for higher number of parts. MTM-1 and MOST were used for a detailed time and motion …


Optimizing Production In An Electronics Manufacturing Industry Using Six Sigma: A Dmaic Approach To Process Enhancement, Shubham Parekh Jan 2024

Optimizing Production In An Electronics Manufacturing Industry Using Six Sigma: A Dmaic Approach To Process Enhancement, Shubham Parekh

All Graduate Theses, Dissertations, and Other Capstone Projects

This paper focuses on the application of DMAIC (Define, Measure, Analyze, Improve and Control) process of Six Sigma methodology for increasing the production numbers in an electronics manufacturing industry. The overall production numbers are improved by identifying the root causes and improving the process efficiency. Detailed analysis of the process cycle time for all stations is conducted and key areas for improvement are identified. Proper implementation of the suggested changes is conducted, and the results are verified. Further recommendations are provided for addressing the key improvement areas for reducing the cycle time of the bottleneck process. The findings highlight the …


Comparative Study Of Robotic And Manual Welding In A Low Volume-High Mix Manufacturing Environment: Case Study Of Cross Head, Niloufer Sarah Jan 2024

Comparative Study Of Robotic And Manual Welding In A Low Volume-High Mix Manufacturing Environment: Case Study Of Cross Head, Niloufer Sarah

All Graduate Theses, Dissertations, and Other Capstone Projects

A comparative study of robotic and manual welding in a low volume high mix manufacturing environment focusing on a truck body part named the Cross head to see if there is a benefit of incorporating robotic welding into the production line. By utilizing predetermined time studies such as Methods Time Measurement 1(MTM-1) and Maynard’s Operation Sequence Technique (MOST) in conjunction with actual welding time and motion study to see which method of time study can be used to extrapolate the times of production for higher number of parts. MTM-1 and MOST were used for a detailed time and motion analysis …


Comparative Study Of Robotic And Manual Welding In A Low Volume-High Mix Manufacturing Environment: Case Study Of Jr Test 3, Mayank Srinivasamurthy Jan 2024

Comparative Study Of Robotic And Manual Welding In A Low Volume-High Mix Manufacturing Environment: Case Study Of Jr Test 3, Mayank Srinivasamurthy

All Graduate Theses, Dissertations, and Other Capstone Projects

This thesis presents a comparative study of robotic and manual welding within a low-volume, high-mix manufacturing environment, focusing on the JR Test 3 case study. It explores the implementation of collaborative robots (co-bots) for robotic welding, emphasizing their flexibility, adaptability, and safety features. The study examines the integration and performance of co-bots. A detailed time and motion study, along with cost analysis, highlights the efficiency gains and quality improvements achieved through robotic welding. The findings underscore the advantages of co-bots in enhancing workflow efficiency, ensuring precision, and maintaining safety standards in dynamic manufacturing environments. The results showed that for this …


River Response To Removal Of A Small Dam And Replacement With A Roughened Channel, Chandler Sabin Jan 2024

River Response To Removal Of A Small Dam And Replacement With A Roughened Channel, Chandler Sabin

All Master's Theses

Relatively few studies have analyzed how the removal of small dams and re-engineering of the channel affect river channel processes. The low-head Nelson Dam was built in 1920 on the Naches River in central Washington, causing two miles of aggraded sediments. This resulted in upstream flooding and excessive downstream incision that led to ineffective irrigation diversions, and hindered fish spawning. Nelson Dam was removed in 2021 and replaced with a graded, roughened, nature-like channel and a newly engineered diversion that was completed in 2023. The research presented here quantifies the effects of the Nelson Dam removal and channel redesign on …


Physiologically Relevant Cardiac Tissue Chips For Cardiovascular Disease Modeling, Sachin Budhathoki Jan 2024

Physiologically Relevant Cardiac Tissue Chips For Cardiovascular Disease Modeling, Sachin Budhathoki

All ETDs from UAB

Despite significant advances in our understanding of the molecular basis of cardiovascular diseases (CVD) and the development of new therapeutics, it remains the number one cause of death worldwide, particularly affecting the aging population. This necessitates the development of models that can more accurately recreate aspects of aging and the interaction of the heart with other organs and systems in the body, including the immune system. Tissue chip models are being increasingly considered for studying cardiac diseases as they can potentially address translational hurdles associated with animal models, yet several challenges hinder their full potential. These include a lack of …


Mechanical Behaviors Of Additively Manufactured Fiber-Reinforced Thermoplastic Composites, Yu-Chao Shih Jan 2024

Mechanical Behaviors Of Additively Manufactured Fiber-Reinforced Thermoplastic Composites, Yu-Chao Shih

All ETDs from UAB

Additive manufacturing (AM) technologies are advantageous in small-batch manufacturing and prototyping functional parts, due to their cost-effectiveness and customizability. Using fiber-reinforced plastic composites (FRP) in extrusion-based AM can significantly improve the mechanical properties compared to neat thermoplastic. However, the two-fold anisotropy introduced by the multiple constituent materials and the layer-by-layer mesostructure can introduce undesired structural weaknesses. Investigating the mechanical behavior and failure mechanism is the key to understanding the synergistic effect of the constituents in FRP and assessing the structural integrity of AM-made FRP. This research work aims to experimentally, analytically, and numerically assess the mechanical behaviors of AM composite …


Removal Of Phosphorous, Copper And Zinc From Stormwater Using Powdered Activated Carbon (Pac) Based Water Treatment Residuals, Foysol Mahmud Jan 2024

Removal Of Phosphorous, Copper And Zinc From Stormwater Using Powdered Activated Carbon (Pac) Based Water Treatment Residuals, Foysol Mahmud

Electronic Theses and Dissertations

The main aim of this research was to evaluate the efficacy of Powdered Activated Carbon (PAC) based water treatment residual (WTR) in eliminating phosphorus (P), Copper (Cu), and Zinc (Zn) from stormwater. The characteristics of the PAC WTR were analyzed, and a series of batch and column tests were conducted to determine its capacity to remove P, Cu, and Zn from stormwater and synthetic solutions. The PAC WTR conformed to the Langmuir isotherm model, demonstrating P adsorption capacities of 3.51 mg/g at pH 5. Regarding Cu and Zn removal, the PAC WTR also adhered to the Langmuir isotherm model, showing …


Feasibility Study Of Managing Peak Cooling Loads To Achieve Energy Cost Reduction In A Northern Climate Campus, Mark Rizkalla Jan 2024

Feasibility Study Of Managing Peak Cooling Loads To Achieve Energy Cost Reduction In A Northern Climate Campus, Mark Rizkalla

Electronic Theses and Dissertations

South Dakota State University Facilities and Services Office is facing the challenge of paying high electricity bills every year, the potential of campus growth will add more burden on the energy needed to cover this demand, especially in summer months when high cooling loads are added to the electrical loads which lead to the peak loads that costs SDSU a large amount of money. The purpose of this research is to study the feasibility of managing the peak loads to reduce energy costs by applying a suitable system that fits SDSU campus nature. The methodology used is studying the capability …


Structural Construction And Surface Modification Of Copper Current Collectors For Lithium Metal Batteries, Yaohua Liang Jan 2024

Structural Construction And Surface Modification Of Copper Current Collectors For Lithium Metal Batteries, Yaohua Liang

Electronic Theses and Dissertations

Graphene, a prevalent anode material in commercial lithium-ion batteries, has reached its theoretical capacity limit. The imperative is to develop high-capacity anode materials to meet the growing demand for energy density. Lithium metal, renowned for its exceptionally high theoretical specific capacity density (3680 mAh g-1) and low reduction potential (-3.04 V, relative to the standard hydrogen electrode), is commonly dubbed the "Holy Grail" for negative electrode materials in high-energy-density batteries. However, practical advancements in lithium metal anodes face obstacles like low Coulombic efficiency, limited cycle life, and heightened reactivity to the electrolyte and internal short circuits resulting from lithium dendrite …


Simulation Of Reacting Supersonic Flow In A Cavity Flameholder, Mohamed Benjelloun Touimi Jan 2024

Simulation Of Reacting Supersonic Flow In A Cavity Flameholder, Mohamed Benjelloun Touimi

Electronic Theses and Dissertations

Scramjet engines, or Supersonic Combustion Ramjets, are pivotal for achieving and maintaining hypersonic flight speeds. These engines leverage the high-speed airflow to compress and mix air and fuel for combustion. A significant challenge in Scramjet engine design is ensuring stable and efficient combustion within this high-speed environment. Cavity flameholders are crucial components that stabilize the combustion process by creating a subsonic region where the fuel-air mixture can ignite and sustain combustion. This research simulates this supersonic flow within the combustion chamber to accurately model and analyze the combustion dynamics. Various turbulence models, including RANS, and DES, are evaluated for their …


Evaluation Of Nutrient Removal From Modified Woodchips And Organic Matter Leached From Tree Leaves After Simulated Wildfire Thermal Alteration, Zengyue Wang Jan 2024

Evaluation Of Nutrient Removal From Modified Woodchips And Organic Matter Leached From Tree Leaves After Simulated Wildfire Thermal Alteration, Zengyue Wang

Electronic Theses and Dissertations

Nonpoint source pollution (NPS) from stormwater runoff, carrying a variety of contaminants, presents substantial challenges to water treatment processes and public health. Among the primary pollutants, phosphate and nitrate significantly contribute to the degradation of water quality, resulting in issues such as eutrophication and methemoglobinemia. Tree leaves, which are a major source of dissolved organic carbon (DOC) in forested watersheds and serve as a key fuel for wildfires, further exacerbate these challenges. Post-wildfire, the altered DOC is mobilized by precipitation, leading to stormwater runoff that impacts natural water bodies and complicates treatment processes, particularly through the formation of hazardous disinfection …


Evaluating The Impact Of Perceptual Loss In Generative Adversarial Models And Diffusion Models For Document Image Enhancement, Farzaneh Karimpour Jan 2024

Evaluating The Impact Of Perceptual Loss In Generative Adversarial Models And Diffusion Models For Document Image Enhancement, Farzaneh Karimpour

Electronic Theses and Dissertations

Documents often suffer from various types of degradation which make them difficult to read and restrict OCR performance. This study investigates the effectiveness of perceptual loss in enhancing document image cleanup by comparing a GAN-based model and a diffusion model. In our experiments, we utilized the DE-GAN model as a GAN-based model and the NAF-DPM model as a diffusion model, both enhanced by incorporating perceptual loss. We then compared the results of both models and evaluated them by using the DIBCO 2013, DIBCO 2017, and H-DIBCO 2018 datasets revealed that our approach consistently outperforms existing state-of-the-art methods. Results showed that …


Comparative Analysis Of Deep Learning-Based Anomaly Detection Models For Gps Spoofing Detection, Hasan Mirzakhaninafchi Jan 2024

Comparative Analysis Of Deep Learning-Based Anomaly Detection Models For Gps Spoofing Detection, Hasan Mirzakhaninafchi

Electronic Theses and Dissertations

As autonomous vehicles (AVs) become integral to modern transportation, their susceptibility to cyber-attacks, particularly GPS spoofing, presents a serious security threat. This study addresses these challenges by applying a suite of deep learning models to enhance the detection of anomalous GPS signals. Focusing on autoencoder-based architectures, the proposed models such as long short-term memory-based variational autoencoder (LSTM-VAE), LSTM-based autoencoder (LSTM-AE), multilayer perceptron-based variational autoencoder (MLP-VAE), MLP-based Autoencoder (MLPAE), Stacked LSTM-based variational autoencoder (Stacked-LSTM-VAE), stacked LSTM-based autoencoder (Stacked-LSTM-AE), memory-augmented-LSTM-VAE (Mem-LSTM-VAE), and time-series-anomaly-detection-generative-adversarial-networks (TadGAN) were trained exclusively on authentic GPS data. This unsupervised learning approach which used for the above-mentioned models enables …


Computational Characterization Of Extracellular Electro-Osmotic Flow During Tissue Repair, Ashley Jorgensen-Blocker Jan 2024

Computational Characterization Of Extracellular Electro-Osmotic Flow During Tissue Repair, Ashley Jorgensen-Blocker

Electronic Theses and Dissertations

Electrical stimulation (ES) therapy promotes the healing of chronic epidermal wounds and suppresses the degeneration of articular cartilage. Despite the success of ES therapy, the underlying mechanisms by which ES promotes tissue repair are largely unknown, preventing the standardization and optimization of treatments. One proposed mechanism involves electro-osmotic flow (EOF), electrically driven water flow generated within close proximity to the cell surface. EOF induces the transport of macromolecules and removes metabolic wastes and inflammatory molecules from these dense tissues through interstitial flow. This dissertation investigates the application of weak electric fields (EFs) to non-excitable cells and the generation of EOF …


An Integrated Hybrid P2p-Dr Networks For A Transactive Energy Market Platform Considering Electricity Network Constraints, Sheroze Liaquat Jan 2024

An Integrated Hybrid P2p-Dr Networks For A Transactive Energy Market Platform Considering Electricity Network Constraints, Sheroze Liaquat

Electronic Theses and Dissertations

No abstract provided.


Evaluation Of Silk Fibroin And Hylauronic Acid As Otic Drug Delivery System Additives; Investigation Of Silk Fibroins Responses To Enviromental Stimulii, Kolton Charles Sandau Jan 2024

Evaluation Of Silk Fibroin And Hylauronic Acid As Otic Drug Delivery System Additives; Investigation Of Silk Fibroins Responses To Enviromental Stimulii, Kolton Charles Sandau

Graduate Student Theses, Dissertations, & Professional Papers

The Serban lab has previously developed and reported on a single application drug delivery system for the treatment of otitis externa. Otitis externa also known as outer ear infections is a very common ailment that impacts large portions of both human and domestic animal populations. Typical treatment for otitis externa typically requires an extended dosing regimen over several days that is inconvenient and can lead to poor clinical outcomes due to poor patient compliance. Our delivery system employs a thixotropic gel to deliver a steady dose of medication over the duration of the infection.

Here we evaluated the reproducibility and …


Mouralherwaqh Coastal Wetland Road Crossing Da'luk, Pakunihanich Nicoli Martin Jan 2024

Mouralherwaqh Coastal Wetland Road Crossing Da'luk, Pakunihanich Nicoli Martin

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 …


Mouralherwaqh Coastal Wetland Road Crossing Da'luk, Romel Robinson Ii Jan 2024

Mouralherwaqh Coastal Wetland Road Crossing Da'luk, Romel Robinson Ii

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 …


Two-Dimensional Hydrodynamic Model Comparison For Fish Habitat Assessment In Rivers, Tyler Caseltine Jan 2024

Two-Dimensional Hydrodynamic Model Comparison For Fish Habitat Assessment In Rivers, Tyler Caseltine

Cal Poly Humboldt theses and projects

Accurate prediction of aquatic habitat availability for salmonids and other aquatic species is crucial for effective river and tributary restoration and management. Two-dimensional (2D) hydrodynamic models have become the standard for simulating depth and velocity conditions in open channel systems, leveraging advances in computational capabilities and spatial data collection. This study compares four 2D hydrodynamic models—SToRM, River2D, HECRAS2D, and SRH2D—using consistent topographic and calibration data, and adhering to Quality Assurance and Quality Control (QA/QC) standards as outlined by the US Fish and Wildlife Service (USFWS) and McBain Associates. The models were evaluated with data from two study sites for their …


Co-Firing Of Lpg And Diesel Fuels Through An Innovative Double Swirl Burner: Combustion Characteristics And Exhaust Emissions, Eslam O. Mater, Karim M. Soliman, A. Abdulnaim, Ahmed Abdelrazik Emara, Ahmed Salah Elsahy, Hany A. Moneib Jan 2024

Co-Firing Of Lpg And Diesel Fuels Through An Innovative Double Swirl Burner: Combustion Characteristics And Exhaust Emissions, Eslam O. Mater, Karim M. Soliman, A. Abdulnaim, Ahmed Abdelrazik Emara, Ahmed Salah Elsahy, Hany A. Moneib

Trends in advanced sciences and technology

The current stringent environmental regulations, the depletion of fossil fuels and the emergence of oil biofuels and synthetic gases had motivated combustion scientists to search for alternative technologies that meet efficient burning, flexible use of multiple fuels and conform to a clean environment. In that respect, several developments had emerged including, low swirl combustion for partially premixed mixtures, “Mild” combustion for diffusion flames. The present experimental study introduces a new concept that combines separate admissions of fuel and air with a central recirculation zone following the diffusion combustion mode, partial premixing within a premix chamber resulting in the creation of …


Air Jet Assisted Combustion Of Oil Diffusion Flames: Effects Of Injection Location And Excess Air Factor, Moustafa Ahmed Gamaleldin, Neama Youssef Ramadan, Ahmed Mohamed Abdulnaim, Ahmed Abdelnasser Adam, Ahmed Abdulrazik Emara, Hany Ahmed Moneib Jan 2024

Air Jet Assisted Combustion Of Oil Diffusion Flames: Effects Of Injection Location And Excess Air Factor, Moustafa Ahmed Gamaleldin, Neama Youssef Ramadan, Ahmed Mohamed Abdulnaim, Ahmed Abdelnasser Adam, Ahmed Abdulrazik Emara, Hany Ahmed Moneib

Trends in advanced sciences and technology

This study investigates a novel methodology for a coaxial disc stabilized burner with a central jet oil spray. It introduces multiple air injection jets within the burner gun's exit section, promoting earlier fuel vaporization and rapid fuel-air mixture formation in the premixing zone. This directly contributes to improved overall combustion efficiency and reduced exhaust emissions. The focus lies on identifying the optimal location for the air injection jets (fixed load, constant jet momentum, and angle) within the exiting premixing zone of the burner gun. In-flame measurements are conducted inside a cylindrical combustor at different air injection locations and varying excess …


Dynamic Analysis And Experimental Verification Of Flexible Unbalance Rotor Supported By Two Identical Journal Bearings, Omar Ahmed, Hussein Sayed, T.A. El-Sayed Jan 2024

Dynamic Analysis And Experimental Verification Of Flexible Unbalance Rotor Supported By Two Identical Journal Bearings, Omar Ahmed, Hussein Sayed, T.A. El-Sayed

Trends in advanced sciences and technology

Abstract BACKGROUND: Analyzing the vibrations for rotor-bearing systems is a critical issue in the field of rotor dynamics. It is crucial to identify rotary machine vibrations, behaviors, and stability conditions. The main causes of vibration in rotating machinery are unbalanced masses, misalignment, mechanical looseness, shaft cracks, and other defects. METHODS: This paper investigates the experimental verification of a theoretical model, using a steel shaft with a disc set at the midpoint, supported by two symmetric fluid film bearings. The study examines the effect of unbalance on the dynamic behavior of the rotor and its vibration characteristics. The experimental investigation involved …


What Can We Learn From A Co-Creation Journey For A Quick Scan Digital Transformation Maturity Assessment Tool For Development Ngos?, Anand Sheombar Jan 2024

What Can We Learn From A Co-Creation Journey For A Quick Scan Digital Transformation Maturity Assessment Tool For Development Ngos?, Anand Sheombar

Journal of International Technology and Information Management

This paper describes the approach and lessons learned from a co-creation process with Dutch development NGOs to create a practical and easy-to-use assessment tool for practitioners to assess the organisation's maturity level of digital transformation. For this study, we applied a design science research methodology, specifically a six-step co-creation approach suitable for developing maturity models. The digital maturity assessment tool (quick scan) created is a domain- specific digital transformation maturity tool for development NGOs rather than a generally applicable tool. This artefact was evaluated using an eight-point Requirements framework for the development of digital maturity assessment tools. By developing a …


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 …