Engineering Commons^™

Cfd Simulation And Shape Optimization Of Supersonic Ejectors For Refrigeration And Desalination Applications, Liju Su

McKelvey School of Engineering Graduate Student Theses & Dissertations

The aim of this thesis is to investigate the detailed flow field inside the supersonic ejector using numerical methods and to optimize the ejector’s mixing chamber wall shape to obtain a maximum entrainment ratio (ER) in order to obtain the highest possible efficiency that can be attained by the ejector. A steam ejector applied in the cooling industry is first studied to determine the most accurate turbulence model for its supersonic jet flow field simulation with mixing with the entrained steam in the mixing chamber. A commercial Computational Fluid Dynamics (CFD) package FLUENT 14.5 along with the meshing tool ICEM …

The Geometric Algorithm Of Inverse And Direct Problems With An Area Solution For The Great Elliptic Arcs, Wei-Kuo Tseng, Jiunn-Liang Guo, Chung-Ping Liu

Journal of Marine Science and Technology–Taiwan

The definition of the connecting edge(s) between two vertices in a geography type is the great elliptic minor arc in Microsoft SQL Server’s Geography Type. Similar to the way an edge is defined by Microsoft SQL Server, an edge in Geodyssey’s Hipparchus library is also defined as a great circle arc on a reference sphere. Using Hipparchus for their computations, IBM’s DB2 Geodetic Extender and Informix Geodetic Datablade share this definition. Compact formulae are given for the great elliptic sailing on a spheroid providing solutions to both the forward and inverse problems with exceptional accuracy, and latitude in terms of …

Effect Of Mortar Coating On Concrete Carbonation, Wen-Hu Tsao, Ming-Te Liang, Jiang-Jhy Chang, Nai-Ming Huang

Journal of Marine Science and Technology–Taiwan

The mechanism of the effect of mortar coating on carbonation of concrete is investigated. Theoretical methods of Fick's first and second laws of linear diffusion are used to calculate the carbonation depth of concrete without and with mortar coating, respectively. Theoretical analyses are also done to obtain the carbonation retard coefficients of mortar coating on concrete with surface coatings. A great deal of well organized experimental tests are carried out to verify the values of calculation. The results of present study indicate that the suitable mortar coating on concrete can effectively delay carbonation of concrete. The carbonation depth is inversely …

Analysis Of Electromagnetic Force Of The Linear Generator In Point Absorber Wave Energy Converters, Zhong-Qiang Zheng, Peng Huang, Da-Xiao Gao, Zong-Yu Chang

Journal of Marine Science and Technology–Taiwan

In recent decades energy shortage and environmental pollution have increasingly become challenges faced by the world. New innovation technology to harness renewable energy such as wave energy is considered to be the key to solve this problem. Point absorber wave energy converter (WEC) is one of the most effective means to utilize wave energy. Several different types of power take off (PTO) devices have been used in the design of point absorber WEC amongst which linear generator has the advantages of direct drive, structural simplicity, high-efficiency and so on. This paper studies the electromagnetic force of the linear generator, and …

Stability Investigation Damaged Ships, Rodrigo Pérez Fernández

Journal of Marine Science and Technology–Taiwan

There are many areas in which naval vessels could improve safety standards, although naval vessels are not necessarily regarded as less secure than the civil vessels. Although the navies never have considered water on deck a problem, it seems that this problem has a critical value in the ship damage stability analysis. As an example, this damage should be investigated if the ship has a low freeboard. For this research various studies and calculations have been carried out on several designed test vessels. It is possible to decide which criteria to use in terms of damages for each type of …

Study Of Different Denoising Methods For Underwater Acoustic Signal, V. Vijaya Baskar, V. Rajendran, E. Logashanmugam

Journal of Marine Science and Technology–Taiwan

Marine Engineering faces certain challenges in recent times due to the prevalence of ambient conditions caused by imbalance in the ecosystem. Underwater ambient noise is primarily a background noise, which is a function of time, location and depth. It is of prime importance to detect the signals such as the sound of a submarine or an echo from a target, surpassing and surmounting this ambient noise. In the absence of the sound from ships and marine life, underwater ambient noise levels are dependent mainly on wind speeds at frequencies between 500 Hz and 50 KHz (Urick, 1984). Since there is …

Shear Strength Of Reinforced Concrete Dapped-End Beams With Shear Span-To-Depth Ratios Larger Than Unity, Wen-Yao Lu, Ting-Chou Chen, Ing-Jaung Lin

Journal of Marine Science and Technology–Taiwan

Test results of 24 reinforced concrete dapped-end beams with shear span-to-depth ratios larger than unity are reported. The main variables studied were compressive strength of concrete, shear span-to-depth ratio, and main reinforcement and vertical stirrups of dapped-end beams. The test results indicate that the dapped-end beams all failed by flexure. The shear strength of dapped-end beams increases with increase in compressive strength of concrete. With smaller shear span-todepth ratio, the dapped-end beams show greater stiffness and ultimate load. The shear strength predicted by the proposed model, the strut-and-tie model of the ACI Code, and the approach of the PCI Design …

Influence Of Raisin Starter Syrup Concentrations On The Properties Of Sourdough And Sourdough Bread, Jean-Yu Hwang, Yung-Shin Shyu

Journal of Marine Science and Technology–Taiwan

The present study evaluates the effects of syrup concentrations of natural raisin microflora culture on the characteristics of sourdough and sourdough bread. The original total titratable acidity (TTA) of the starter solutions were between 10.30 and 10.45 mL, after 96 hours of incubation, the TTA of the starter solution increased to 11.30-11.85 mL. The greatest pH decrease and TTA increase occurred in the RS50 group. The microstructure of the control bread was rougher and contained more ungelatinized starch particles than bread made with sourdough. The overall acceptability and flavor of bread made using sourdough with the 150 g/L syrup solution …

Describing Landscape Structure Improvement According To Experimental Results, Fu-Ming Chang, Ning-Chien Tung

Journal of Marine Science and Technology–Taiwan

This study investigated silt movement and the influence of fine sand on downstream ecology during movement by using a small indoor physical model for simulating onsite conditions. The obtained data were analyzed to determine the impact of silt on ecological habitats and can serve as a reference for future onsite and ecology investigations. Before a dam was removed to allow a downstream riverway to restore the initial environment, the riverway stabilized at approximately 960 s, and the dam was removed at approximately 1140 s. After the dam was removed, the silt in each channel section evidently increased, and after a …

Composite Coastal Protection Methods Used At Cijin Coast, Taiwan, Hong-Mo Wu, Shao-Gu Kuo, Yen-Ting Lai, Li-An Kuo, Chia-Yan Cheng, Jyh-Cheng Chu, Yang-Yih Chen, John R. C. Hsu

Journal of Marine Science and Technology–Taiwan

Cijin Coast has suffered from severe beach erosion and a consequent coastline retreat. To analyze the trend of topographic evolution of Cijin Coast, bathymetric data from field investigation were used and both numerical simulation and physical modeling were implemented in the wave basin to obtain the corresponding parameters that replicate similar phenomena. To protect Cijin Coast, composite coastal protection methods, such as submerged detached breakwaters accompanied with artificial nourishments, were proposed. Parameters used in previous studies were employed to test the proposed protection methods, and the results showed that the methods were effective in preventing the consequent retreat of the …

Improving Detection Technique For Flight Recorders Of The Distress Airplanes Crashed Into Ocean By Integrating Inertial Navigation System Into Underwater Locator Beacon, Sheng-Shih Wang, Hsien-Sen Hung, Jyh-Jier Ho, Jie-Xian Lin, Chi-Hsiao Yeh

Journal of Marine Science and Technology–Taiwan

Flight recorder, used to analyze distress reasons, is equipped with underwater locator beacon (ULB) for being detected and recovered easily in sea. According to the recovery report for the Air France flight no. AF447 distress airplane, it nearly took two years and cost 40 million US dollars to search and recover the flight recorders. Apparently, future aviation safety could be greatly improved if earlier recovery of the flight recorders would reveal the crash reasons sooner. Therefore, this paper is aimed to develop an enhanced ULB, which integrates inexpensive inertial navigation system (INS) into ULB, for a cost-effective and time-saving operation …

Effects Of Generator Parameters And Transformer Disposal On Dynamics Of A High-Penetration No-Storage Wind-Diesel System, Chi-Hsiang Lin

Journal of Marine Science and Technology–Taiwan

In this paper, dynamics of a high-penetration, no-storage wind-diesel (HPNSWD) system subjected to line faults are studied. It is found that the effect of induction generator electrical parameters on generator electromagnetic torque, system frequency and generator terminal voltage is significant, especially for the rotor resistance, which is able to significantly affect all the three target performances. Therefore, it will be the most effective way to improve the system dynamics by controlling the rotor resistance. It is also found that the system dynamics would be significantly improved by disposing a distribution transformer. However, the effectiveness depends on the installation position. A …

Coupling Vof/Plic And Embedding Method For Simulating Wave Breaking On A Sloping Beach, Tai-Wen Hsu, Chih-Min Hsieh, Chin-Yen Tsai, Shan-Hwei Ou

Journal of Marine Science and Technology–Taiwan

A 2-D numerical model was developed to simulate wave breaking on a sloping beach. The model solves the Reynolds Averaged Navier-Stokes (RANS) equations coupled with the k-ε turbulence closure model. To track free surface configurations, the volume of fluid with piecewise linear interface calculation (VOF/PLIC) is employed. An embedding method (EB) is also used to treat complex bottom topography. Coupling these two methods for simulating wave breaking on a sloping beach, good agreement between numerical results and laboratory observations is found for spilling breaker. Wave breaking characteristics is in terms of free surface profiles, mean velocities and wave heights based …

Elastohydrodynamic Lubrication Of Circular Contacts At Pure Squeeze Motion Involving The Mixture Of Two Lubricants, Li-Ming Chu, Yuh-Ping Chang, Jer-Jia Sheu

Journal of Marine Science and Technology–Taiwan

This study investigated the pure squeeze elastohydrodynamic lubrication (EHL) motion of circular contacts by using mixed rheology fluid models under constant load conditions. The lubricant was a homogeneous mixture of a Newtonian base oil and couple stress fluid at various volume fractions. The simulation results revealed that the effect of the couple stress fluid was equivalent to enhancing the viscosity of the lubricant. Therefore, the central film thickness and minimum film thickness increased with the volume fraction of the couple stress fluid (ν). The central pressure decreased as ν increased. In addition, the normal squeeze velocity followed the ensuing order: …

The New Method To Evaluate The Uplift Capacity Of Belled Piles In Sandy Soil, Jaw-Guei Lin, Shih-Yu Hsu, San-Shyan Lin

Journal of Marine Science and Technology–Taiwan

In conventional geotechnical engineering, the pull out of pile is always blamed only on the shear failure of the soil caused by the uplift force developed from the tip of the pile. For the belled pile, however, the enlarged foundation plays an important role to against the compression/uplift load, and the current theories for estimating the uplift capacities of the pile were found more than 50% relative error from measured. In this study, a new method for estimating the ultimate uplift capacity of the belled pile embedded in sandy soil was developed by taking into account the elastic/plastic behavior of …

The Kriging Cloud Computing Framework: Interpolation Of Topography By Cloud Computing With The Kriging Algorithm, Cheng-Tsan Lai, Sung-Shan Hsiao, Hui-Ming Fang, Edward H. Wang

Journal of Marine Science and Technology–Taiwan

Spatial information surveyed by photogrammetry, airborne LiDAR and Mobile Measurement System (MMS) above ground level can be analyzed by scientists using standard geostatistical methodologies such as ordinary Kriging and sequential Gaussian simulation to interpolate heterogeneities of profiles from sparse sample data. Proven effective by researchers, the Kriging algorithm model is used by commercial data analysis packages for instant interpolation. However, meaningful and reliable results only come with a comprehensive understanding of the variogram associated with valid mathematical functions. To capture spatial landscape variations from massive sample grids of satellite images, this paper presents a cloud computing-based automation approach to improve …

Effects Of Battery Energy Storage System On The Operating Schedule Of A Renewable Energy Based Tou Rate Industrial User Under Competitive Environment, Chun-Lung Chen, Yu-Liang Lin, Wen-Yu Fu

Journal of Marine Science and Technology–Taiwan

With increasing development of smart grid and restructuring of the power industry, the problem of operating schedule for a time-of-use (TOU) rate industrial customer may become a more important issue due to the inclusion of the variations in the TOU rate structures. This paper develops a new algorithm, named intelligent particle swarm optimization (INPSO), to solve the operating schedule of a renewable energy based TOU rate industrial user with battery energy storage system (BESS). Adding another particle best (Pbestap) item with a diversity based judgment mechanism, proposed INPSO algorithm can give a good direction to enhance its search capacity that …

Unraveling The Formation Of Continental Crust : A Review And Outlook, Eason Hong, Wei-Ting Kao

Journal of Marine Science and Technology–Taiwan

The early Earth is generally believed to be a hot planet with a primitive basaltic oceanic crust. However, the question of how a batholiths-bearing continent was formed is still unresolved. Although many hypothetical interpretations seem appealing, the origin and volume dilemma of the batholiths is still under debate. According to recent literature, the Hadean Ocean is characterized by heat, acidity and reduction, significantly unlike its counterparts in Earth's history. We have found that this crucial marine setting, favoring the chemical weathering of basaltic rocks, is the key element for forming and stabilizing the primitive continents through convergent tectonics and the …

Online Modeling And Tuning Of Parallel Stream Processing Systems, Jonathan Curtis Beard

McKelvey School of Engineering Graduate Student Theses & Dissertations

Writing performant computer programs is hard. Code for high performance applications is profiled, tweaked, and re-factored for months specifically for the hardware for which it is to run. Consumer application code doesn't get the benefit of endless massaging that benefits high performance code, even though heterogeneous processor environments are beginning to resemble those in more performance oriented arenas. This thesis offers a path to performant, parallel code (through stream processing) which is tuned online and automatically adapts to the environment it is given. This approach has the potential to reduce the tuning costs associated with high performance code and brings …

Spectrum Management Using Markov Decision Processes, John Leo Meier

McKelvey School of Engineering Graduate Student Theses & Dissertations

Abstract: The advent of cognitive radio technology has enabled dramatically more options in the use of RF spectrum, allowing multiple transmitters to effectively share spectrum in ways that were previously unavailable (either due to technical limitations or regulatory restrictions). In this dissertation, we investigate approaches to managing RF spectrum use, with a focus on combining multiple control decisions in a mutually beneficial manner.

Our approach to making spectrum management decisions is grounded in Markov decision theory, which has a rich formal foundation and is frequently used to guide decision making in other disciplines. Here, we develop a set of Markov …

Spontaneous Firing Of Sensory Neurons Modulates The Gain In The Downstream Circuit Of A Simple Olfactory System, Matthew O'Neill

McKelvey School of Engineering Graduate Student Theses & Dissertations

In locusts and other insects, odorants are transduced into electrical signal by the olfactory receptor neurons and transmitted to central circuits for further processing. Previous studies have shown that exogenous variables (e.g., flow rates, humidity, temperature, odor mixtures, etc.) can influence the responses of the sensory neurons and therefore modulate the central circuits. However, how the sensory neuron activity is manipulated to achieve adaptive gain control in the following circuit is yet to be understood. It is possible that the magnitude of the stimulus-evoked response in the receptor neurons, their spontaneous activity, or both of these factors can change how …

Process And Reactor Level Simulations Of Calcium Looping Combustion, Wei Dai

McKelvey School of Engineering Graduate Student Theses & Dissertations

Calcium looping (CaL) is a recent technology for carbon capture from coal fired power plants which consumes less energy than other approaches such as oxy-fuel. In the first part of this thesis, a system level model is developed in ASPEN PLUS to calculate the energy penalty of introducing Calcium looping in a coal fired power plant. Several simplifications and assumptions are made to model the Calcium looping process. The relationship between the energy penalty due to CaL and carbon capture efficiency is used to validate the process model for both pre-combustion CaL and post-combustion CaL; it agrees well with the …

Diamond Coated Wire Cutting Of Solar Si Ingots: New Insights Using Raman Microspectroscopy, Junting Yang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Diamond embedded abrasive wire (henceforth called diamond wire) sawing process of Si is a highly efficient technique for rapid wafering of solar Si ingots. However, the root causes for cutting efficiency losses are unknown. One approach to understanding this complex process is to study 1) diamond particles on diamond coated wire (DCW) and 2) Si swarf collected during cutting process. In this thesis, we use confocal, micro Raman spectroscopy to unravel loss mechanisms of wafer sawing efficiency.

In the first part, we analyze the diamond microparticles which perform the sawing. By analyzing the phase transformation and stress distribution on single …

System Level And Reactor Level Simulations Of Chemical Looping Combustion And Chemical Looping With Oxygen Uncoupling, Xiao Zhang

McKelvey School of Engineering Graduate Student Theses & Dissertations

No abstract provided.

Growth Factor Gradient Formation And Release From Peg Microspheres For Nerve Regeneration., Jacob Roam

McKelvey School of Engineering Graduate Student Theses & Dissertations

Many biological processes depend on concentration gradients in signaling molecules. Thus, introduction of spatial patterning of proteins, while retaining activity and releasability, will be critical for the field of regenerative medicine. In particular, the area of nerve regeneration is in need of innovations to improve outcomes. Only about 25% of surgical patients with peripheral nerve damage (~200,000 surgical interventions performed each year) regain full motor function with less than 3% regaining sensation. The use of nerve guidance conduits (NGC’s) which are filled with biomimetic scaffolds is one treatment being explored. These scaffolds, however, lack the spatial patterning of proteins found …

Sustained Dual Drug Delivery Of Anti-Inhibitory Molecules For Spinal Cord Injury Treatment, Thomas Wilems

McKelvey School of Engineering Graduate Student Theses & Dissertations

Regeneration of lost synaptic connections following spinal cord injury (SCI) is limited due to local ischemia, cell death, and an excitotoxic environment, which leads to the development of an inhibitory glial scar surrounding a cystic cavity. Myelin-associated inhibitors (MAIs) and chondroitin sulfate proteoglycans (CSPGs) are major inhibitors to axon growth inhibition found within the glial scar and limit functional recovery. The NEP1-40 peptide competitively binds the Nogo receptor and partially blocks inhibition from MAIs, while chondroitinase ABC (ChABC) enzymatically digests CSPGs, which are upregulated at the site of injury. The first part of this work develops drug delivery systems which …

Bio-Inspired Multi-Spectral Imaging Sensors And Algorithms For Image Guided Surgery, Shengkui Gao

McKelvey School of Engineering Graduate Student Theses & Dissertations

Image guided surgery (IGS) utilizes emerging imaging technologies to provide additional structural and functional information to the physician in clinical settings. This additional visual information can help physicians delineate cancerous tissue during resection as well as avoid damage to near-by healthy tissue. Near-infrared (NIR) fluorescence imaging (700 nm to 900 nm wavelengths) is a promising imaging modality for IGS, namely for the following reasons: First, tissue absorption and scattering in the NIR window is very low, which allows for deeper imaging and localization of tumor tissue in the range of several millimeters to a centimeter depending on the tissue surrounding …

Photoacoustic Microscopy And Photoacoustic Computed Tomography Using High-Frequency Linear Array Ultrasonic Transducers, Guo Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

Photoacoustic tomography (PAT) is a highly promising imaging technology which forms images by detecting the induced pressure waves resulting from pulsed light absorption in biological tissues. Because the excitation source is light, PAT is a very safe, non-ionizing, and non-carcinogenic imaging technology. In biomedicine, PAT has the unique advantage of probing endogenous optical absorbers at different length scales with 100% relative sensitivity. With such scalability, PAT can image anatomical, functional, metabolic, molecular, and genetic contrasts of vasculature, hemodynamics, oxygen metabolism, biomarkers, and gene expression. Among several implementations of PAT, optical-resolution photoacoustic microscopy (OR-PAM) and photoacoustic computed tomography (PACT) are two …

High Resolution Multi-Parametric Diagnostics And Therapy Of Atrial Fibrillation: Chasing Arrhythmia Vulnerabilities In The Spatial Domain, Sarah Gutbrod

McKelvey School of Engineering Graduate Student Theses & Dissertations

After a century of research, atrial fibrillation (AF) remains a challenging disease to study and exceptionally resilient to treatment. Unfortunately, AF is becoming a massive burden on the health care system with an increasing population of susceptible elderly patients and expensive unreliable treatment options. Pharmacological therapies continue to be disappointingly ineffective or are hampered by side effects due to the ubiquitous nature of ion channel targets throughout the body. Ablative therapy for atrial tachyarrhythmias is growing in acceptance. However, ablation procedures can be complex, leading to varying levels of recurrence, and have a number of serious risks. The high recurrence …

Using Fluorescence – Polarization Endoscopy In Detection Of Precancerous And Cancerous Lesions In Colon And Pancreatic Cancer, Tauseef Charanya

McKelvey School of Engineering Graduate Student Theses & Dissertations

Colitis-associated cancer (CAC) arises from premalignant flat lesions of the colon, which are difficult to detect with current endoscopic screening approaches. We have developed a complementary fluorescence and polarization reporting strategy that combines the unique biochemical and physical properties of dysplasia and cancer for real time detection of these lesions. Utilizing a new thermoresponsive sol-gel formulation with targeted molecular probe allowed topical application and detection of precancerous and cancerous lesions during endoscopy. Incorporation of nanowire-filtered polarization imaging into NIR fluorescence endoscopy served as a validation strategy prior to obtaining biopsies.

In order to reduce repeat surgeries arising from incomplete tumor …