Engineering Commons^™

Supercritical Co2 Extraction Of Oil From Henna Flower: Experimental, Mathematical Modeling, And Antioxidant Activity, Bushra Saeed Mohammed Dohai

Theses

Henna is a plant that has been used traditionally for coloring nail, skin, and hair, and as medicinal plant. The supercritical fluid technology offers a considerable promise as extraction media due to its advantages over other conventional extraction techniques. The extraction of volatile components from flowers of henna was studied using supercritical carbon dioxide at temperatures and pressures ranging from 35 to 55°C and 80 to 120 bar, respectively. A maximum extraction yield of 31 % from 2g of henna flowers was obtained at 45 °C and 120 bar. The composition of the extracts was investigated by gas chromatography technique. …

Study On Fracture Behavior Of Aa5083–H111 Friction Stir Welded Joint, Mohammed El Sayed Allam

Theses

The fracture behavior of friction stir welded joints of aluminum alloy 5083-H111 was studied in this investigation. Different samples of stir welded joints at variable tool rotational speeds (1660 rpm, 850 rpm, and 675 rpm), different traveling speeds (24, 42, 55, 74, and 98 mm/min), and different tool pin shapes (cylindrical, tapered and threaded) were studied to investigate the effect of process parameters on the joint strength/load-bearing capacity. A series of tensile tests using an MTS machine, scanning electron microscope (SEM) analysis, and optical microscope analysis was conducted to study the effect of varying the rotational speed, traveling speed, and …

Hydrogen Storage In Pt/Carbon Nanotube Sheets, An-Yu Ma

Theses

Three types of self-assembled carbon nanotube (CNT) sheets, for example, carboxylic functionalized multi-walled CNTs (MWNTs-COOH), pure multi-walled CNTs (MWNTs), and pure single-walled CNTs (SWNTs), were prepared as substrates by ambient environment vacuum filtration of suspensions of the nanotubes. To enhance hydrogen storage on the CNTs, platinum particles were deposited on the three types of CNT sheets using two processes: electrodeposition (ED) using a DC power source and electrochemical deposition under cyclic voltammetry (CV). To verify platinum deposition on the surface of the CNT sheets, a Scanning Electron Microscope (SEM) was used to obtain images, and Energy Dispersive X-ray (EDX) spectroscopy …

Preparation Of Different Polyamide Nanofiltration Membranes By Interfacial Polymerization And The Effect Of Post-Polymerization Treatment On Separation Performance, Yu Qin

Theses

Interfacial polymerization (IP) is a powerful technique for fabrication of thin film composite (TFC) membranes. In this study, polyamide nanofiltration (NF) composite membranes ware prepared by interfacial polymerization of polyethylenimine (PEI) or m-phenylene diamine (MPD) with isophthaloyl dichloride (IPD) on the surface of a porous polyethersulfone (PES) support. Concentrations of monomer reactants for this reaction were decided by equivalent weight ratio. A standard IP procedure was applied to successfully coat PES flat films. After preparation, three different post-polymerization treatments were employed and one optimal treatment was proven after membrane testing.

The TFC flat film membranes were characterized by nanofiltration of …

Neuralsta: A Software Tool For Neural Stimulation And Recording Applications With A Laser Control, Rimi Sahu

Theses

The subject of this thesis is a software tool created in Matlab ® for neural stimulation and recording of the evoked potentials. The stimulation output can be delivered in electrical units for immediate use for neural stimulation or as a power control signal to a laser. NeuralSTA is designed to generate arbitrary waveforms of stimulation and simultaneously record the neural response while implementing the spike triggered averaging (STA) method, hence the name NeuralSTA. The output (stimulation) signal can be created in monophasic, biphasic or inverted monophasic forms (for laser control applications). Controls for pulse modulation allow shaping of the pulse …

The Mechanical Testing Of Single Nanofiber, Pratik Manohar Dahule

Theses

Polymer nanofibers exhibit properties that make them a favorable material for the development of tissue engineering scaffolds, filtration devices, sensors, and high strength lightweight materials. Perfectly aligned PLLA Nanofibers were fabricated by an electrospinning technique under optimum conditions and the diameter of the electrospun fibers can easily be tailored by adjusting the concentration of the polymer solution. To align the nanofibers, special arrangement was made in terms of two aluminum plates. Good alignment of polymer nanofibers on specimen was confirmed by SEM observation. The effect of different electro-spinning parameters on maximum fiber length, average fiber diameter, diameter uniformity, and fiber …

Combustion Dynamics Of Individual Reactive Material Particles, Carlo Francisco Badiola

Theses

Metallic reactive powders are widely used as solid fuels, pyrotechnic materials, and components of enhanced blast explosives. Metals are attractive because of their high combustion enthalpies and temperatures. Quantitative descriptions of the combustion processes and mechanisms for both pure metal and composite particles are also desired for their proper implementation in specific applications. Among reactive metals, Al is used most widely and its combustion has been studied extensively. A recently developed experimental setup using laser-ignited metal powders enabled one to record optical signatures for time-resolved combustion instances for 2-25 µm diameter aluminum particles burning in different atmospheres. Individual particle diameters …

Neural Differentiation Of Pluripotent Stem Cells And Applications To Micropatterned Agarose Hydrogel For Nerve Guidance, Jamila S. Gittens

Theses

Many central nervous system (CNS) disorders are attributable to damaged oligodendrocytes, the cells that form the myelin sheath of axons. An effective source of human oligodendrocytes is crucial, making pluripotent stem cells, such as embryonic stem (ES) cells, an attractive source for nerve tissue repair and regeneration due to their unlimited capacity for self-renewal and their ability to differentiate into all major cell lineages. Bioengineered 3-D hydrogel culture systems have the potential to elucidate mechanisms required for regeneration of CNS cells. The goals of this study are: (1) to investigate the effects of retinoic acid (RA), sonic hedgehog (shh) agonist, …

Development Of 3-D Liver Model For Drug Screening Applications, Divya Rajendran

Theses

The need for a an in vitro drug screening system that mimics the structural organization of natural liver for multi-functionality and maintenance of hepatocytes has become vital in the drug development process. The objective of this study was to engineer a three-dimensional (3-D) liver model using chitosan-based nanofiber scaffolds and co-culture system (adult rat hepatocytes and 3T3-J2 fibroblasts) to mimic the natural liver and to justify its application for in vitro drug screening. Chitosan nanofiber scaffolds were fabricated by electrospinning technique. In order to promote cell adhesion on the chitosan scaffolds, the scaffolds were coated with a cell adhesion molecule, …

Development Of Gis Database For Hayward Fault, Olugbope Maku

Theses

Earthquake activity and its attendant effects on the earth surface have been a major concern for some time now, especially considering their negative effects in loss of human life, property damage including the emotional impact on witnesses. This study focuses on the Hayward Fault, located in the heart of population center in Contra Costa County of the San Francisco Bay Area, California.

Geographical Information System (GIS) has proved to be a valuable tool in recent years in the study and analysis of earthquakes to complement emergency response efforts. GIS has been adapted to estimate the impact of the geologic hazards …

Temperature Elevations Due To Nir Exposure In The Brain Tissue, Ali Ersen

Theses

Near infrared (NIR) lasers have been used in medical applications both for diagnostic and therapeutic purposes. Temperature elevation profile inside the tissue is a critical factor that needs to be better understood in these applications. The purpose of this study is to determine the temperature distribution due to a low power N I R laser irradiation in living neural tissue. Temperature measurements were made directly using a thermocouple probe inside the rat brain cortex within the sagittal plane. The spatial map indicates that N I R light penetrates more readily in the vertical directions than the spreading in the horizontal …

Single-Carrier Frequency Domain Equalization Using Subband Decomposition For Optical Wireless Communications, Di Mu

Theses

Optical wireless communication is intended to be applied into indoor and visual distance high-rate data transmission, which is complementary to radio frequency communications. There are specific problems and requirements in optical wireless communications compared with radio frequency communications. Single-carrier frequency domain equalization (SCFDE) is a transmission scheme which has been considered as an alternative of orthogonal frequency-division multiplexing (OFDM), because it has most of the advantages of OFDM and avoids the problems of OFDM. Subband decomposition is a multi-resolution signal analysis and synthesis method, using quadrature mirror filter (QMF) bank to convert time-domain signal to frequency-domain subbands. As a time-to-frequency …

Analysis And Mitigation Of Carrier Frequency Offset For Uplink Of Ofdma, Abhishek R. Panchal

Theses

Orthogonal Frequency Division Multiplexing (OFDM) is being used in many wireless standards because of its immunity to multipath fading, high spectral efficiency and simple implementation, making it suitable for high data rate multimedia wireless applications. One of the significant drawbacks of the OFDM is its sensitivity to Carrier Frequency Offset (CFO). CFO causes Inter Carrier Interference (ICI) between subcarriers and Multiple User Interference (MUI) at Uplink between different users. ICI and MUI at uplink cause significant degradation in the performance of the receiver, therefore, to improve the receiver performance up to acceptable level, compensation of the CFO becomes necessary.

In …

Soy Protein-Poly (L-Lactic Acid) Blend Nanofibers For Drug Delivery Of Nardostachys Jatamansi, Swetha Tiwari

Theses

Electrospun nanofibers when nanofi bers are impregnated with drugs play a significant role in drug delivery. Nanomedical approaches to drug delivery focus on developing nanoscale particles or molecules to improve the bioavailab ility of a drug.

Biodegradable nanofibers were developed using Poly (L – lactic acid) and Soy protein for the delivery of an ayurvedic drug, Nardostachys jatamansi. A weighed quantity of powdered drug – Nardostachys Jatamansi was subjected to Soxhlet extraction using water and ethanol in equal quantities. Various blends of the drug extract and soy protein solution are prepared and mixed in Poly (L-lactic acid). Nanofibers of …

Dynamic Friction: Measurement And Results, Yanal Jij

Theses

Friction has been known as a phenomenon since Leonardo da Vinci era. From that time and through the last four centuries, scientists tried to understand this phenomenon in an effort to overcome its undesired side effects which include energy loss, parts wearing, and errors in control systems. Much has been achieved in studying friction and many experiments have been conducted in this field. These experiments resulted in a mounting evidence that friction is a dynamic phenomenon.

This thesis presents an apparatus that measures dynamic friction in linear motion and the results obtained using this apparatus. The apparatus consists of a …

Alendronate Treatment Elicits A Reduction In Fatigue-Life Of Canine Cortical Bone, Joseph Ryan Geissler

Theses

Bone serves contradictory needs; bone must be strong yet light, and stiff yet flexible. At the tissue level bone material withstands cyclic loading without failing by dissipating energy via the formation and accumulation of microdamage. Proper removal of this damage in exchange for fresh tissue is vital to bone maintenance, and is achieved through a remodeling process. Imbalanced remodeling leads to osteoporotic fractures. Bisphosphonate drugs are proven to reduce fracture risk. However, the long-term effects of bisphosphonates on tissue-level properties are unknown. This study characterized the fatigue-life of cortical bone tissue after bisphosphonate treatment with alendronate (Aln). 1 1th ribs …

A New Method For Node Ranking For Voltage Stability In Power Systems, Hongxiang Li

Theses

The voltage collapse in power system is a major concern for reliable operation of these systems. In this thesis, a method is proposed to determine the load margins at load nodes (loadability limits). A good portion of the computation to obtain those margins is routinely done when solving the power flow problem, thus the computational effort is greatly reduced. The proposed method is based on the fact that when voltage collapse occurs the Jacobian matrix, that is calculated when performing power flow analysis, is singular. The relationships between the elements of the Jacobian matrix and the nodal powers are exploited …

Theoretical Prediction Of Joint Reaction Force In A Dynamic General 3-D Pendulum Tree Model For Human Or Animal Motion, Sucheta Goyal

Theses

Lagrangian dynamics and the method of superfluous coordinates are applied to predict dynamic joint reaction forces in an idealized flexible model of a branched 3-D pendulum tree system. The number of segments and joints on the tree are adjustable as is the branching tree pattern. The segments that comprise the tree are assumed to be one- dimensional rigid rods containing a discrete set of mass points that is both flexible in number and distribution on the tree. The idealized 3-D pendulum tree system is intended to provide a flexible theoretical framework to model and better understand the dynamics of human …

Visualising Urban Flooding Scenarios Using Video Game Technology, William Elliott Lynn

Theses

This thesis investigates the application of computer graphics to the visualisation of urban flooding scenarios. The demand for urban flooding visualisations is presented in the context of an EU wide climate change response strategy. An analysis of the requirements from various stakeholders is presented and a strategy that addresses these requirements is synthesised. A study on the appropriate computer graphics methods and technologies is outlined and limitations of current technologies are assessed. Systems that solve these limitations are described and the result of usability and user acceptance testing are offered as evidence.

Road Networks Management In The Federal Cities (Entrance And Exits In Ajman), Mohammed Ahmed Abdulrazaq Yousuf Al Awadi

Theses

The aim of this thesis is to discuss the management of infrastructure in the federal union specially the road entrances between neighboring states. To understand how important is it on the social and economic development, to measure how easy to reach the deferent part of city within reasonable period. The hierarchy of the road networks in the city.

Second chapter describe the Arab Emirates before the union and the different scenarios till it's become United Arab Emirates, the relations between different emirates within union, political systems within emirate itself and In the federal level, social and economic systems. The care …

The Performance Of Irish Grown Timber Composites Under Fire Conditions, Cillian Murphy

Theses

In comparison with many European countries Ireland does not make the most effective use of its native timber. It is good economic and environmental practice to promote the more efficient utilization of this natural resource. In recent years there has been a revival in the use of timber in multi-storey construction which predominantly utilises load bearing exposed timber composite members. These timber composites are typically manufactured in Europe using European timber.

The current study investigates the viability of using Irish grown timber composites as a direct replacement in these load bearing members. The main areas of focus will be the …

Voltage Rise Mitigation In A Weak Distribution Network Due To The Impact Of Distributed Generation, Donal Caples

Theses

There are numerous aspects of a distribution network that must be studied in order to determine the maximum size of distributed generation that can be accommodated on the distribution network before supply standards are breached. Voltage rise is one of the main aspects of concern when connecting a distributed generator to a distribution network and this thesis develops the understanding of this phenomenon and concludes with a real life study.

Mathematical and computer simulation software examples within this thesis demonstrate how voltage rise can be reduced to the maximum allowable limit, a major concern if the capacity of a distributed …

An Analysis Of Dredge Material Reuse Techniques For Ireland, Colm Sheehan

Theses

This thesis examines the use and applicability of a range of dredge material management techniques for the Republic of Ireland which will ultimately assist the stakeholders in the industry in assessing the available dredge material management options. A detailed study is presented into the critical parameters required for successful implementation of a range of dredge material management options. An overview of the Irish dredging industry including current dredge material management practice is presented. This is complemented by a detailed critical analysis of the industry which identifies areas requiring development and future challenges for the dredging industry in Ireland. To further …

A Study Of Creep And Shrinkage In Concrete With A Consideration Of Its Effects On Curved Post-Tensioned Concrete Bridges, William O'Sullivan

Theses

The first objective of the project was to explore the differences between Ordinary Portland Cement (OPC) and Ground Granulated Blast-Furnace Slag (GGBS) cement. The use of GGBS cement concrete is increasing in industry due to the environmental and durability benefits it gives compared with OPC concrete. Data on the creep properties of GGBS cement concrete is limited compared with the data that is available for OPC concrete. Laboratory testing was undertaken to determine the different effects of creep on OPC concrete and GGBS concrete.

The second project objective was to research the effects of creep on post - tensioned curved …

The Design And Development Of A Substitution Device For The Visually Impaired., Kieran John O'Callaghan

Theses

Current sensory substitution systems for the visually impaired are limited in terms of their spatial and depth resolution capabilities. They are unable to relay real-time 3D spatial information regarding objects in the direct path of the user. Recent advances in 3D imaging technology have presented new opportunities to develop improved sensory substitution systems to compensate for visual sensory loss. The present study established the design criteria, designed, manufactured and evaluated the performance of a real-time vision substitution device called VisionRE.

Knowledge obtained from a literature review of Human Machine Interfaces (HMIs), feedback from visually impaired focus groups and 3D electrode …

A Distributed Model Predictive Control For Multi-Agent Multi-Rate Systems, Samira Roshany-Yamchi

Theses

In this thesis, a new method is proposed to control multi-agent multi-rate systems with linear dynamics that are coupled via inputs and states. These systems are multi-rate in the sense that either output measurements or input updates are not available at certain sampling. Such systems can arise when the number of sensors is less than the number of variables to be controlled or when measurements of outputs cannot be completed simultaneously because of applicational limitations. The multi-rate nature gives rise to lack of information which will cause uncertainty in the system's performance.

The proposal is to control such systems with …

A Design Tool For Wsn Design In Buildings, Antony Guinard

Theses

The combination of sensing, processing, communication and actuation has made the monitoring and operation of buildings a significant emerging application area for Wireless Sensor Networks (WSN). The design, implementation and management of WSN is a complex task requiring a broad spectrum of disciplines such as networking and protocols, information management and embedding engineering to be successful. Indoor environments in particular pose a number of challenges that make the design of wireless networks a difficult task. These include the influence of obstacles and people on radio propagation, ever evolving building layout and interference from other wireless networks. The large-scale adoption of …

Settlement Of Municipal Solid Waste, Emmet Burke

Theses

The mechanical properties of waste (compression index, elastic modulus, stresses) are an important aspect for the design, operation and post-closure uses of landfills. In recent years the requirement to utilise the acreage that the landfill occupies to its maximum potential has necessitated the landfill structure to accommodate a greater volume of waste over a smaller plan area. This pushes the boundaries of design relating to side-slope and infrastructural elements of landfill structures.

The objectives of this research were identified from significant gaps in the knowledge relating to the settlement and mechanical properties of municipal solid waste. The main objectives are …

Optimisation Of Cold-Formed Steel Purlin Cross-Sections, Matt Clifford

Theses

The subject of buckling of steel members is introduced and the critical nature of local buckling in slender members is highlighted.

The main thrust of work this semester is an investigation into the following buckling modes:

Flexural buckling;

Lateral torsional buckling;

Torsional buckling;

Shear buckling;

Web buckling;

Distortional buckling;

Local buckling.

This investigation has three main components:

1. Review of theory, books and appropriate published work;

2. Investigation into the relevant parts of Eurocode 3;

3. Finite element analysis using the LUSAS FE program to illustrate the various buckling modes.

Finally, the areas to be covered in the Realisation Stage …

Effects Of Cyclic Loading On Offshore Foundation Systems, Shane Browne

Theses

A brief description of the various offshore foundation systems currently available is provided in this report, including the advantages and disadvantages for each system and water depth in which they can be used. These foundation types include floating structures, jacket structures, gravity base structures and the monopile foundation, on which this research specifically focuses.

The monotonic lateral loading of the monopile structure is also examined and the reasons why monotonic testing is required are highlighted, along with the potential analysis that can be generated to improve the design of the monopile foundation. A review of previous test programmes for monopiles …