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

Engineering Commons™

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

2014

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 7081 - 7110 of 7238

Full-Text Articles in Engineering

Optimal Reactive Power Flow Solution In Multiterminal Ac-Dc Systems Based On Artificial Bee Colony Algorithm, Faruk Yalçin, Uğur Ari̇foğlu Jan 2014

Optimal Reactive Power Flow Solution In Multiterminal Ac-Dc Systems Based On Artificial Bee Colony Algorithm, Faruk Yalçin, Uğur Ari̇foğlu

Turkish Journal of Electrical Engineering and Computer Sciences

Active power loss optimization is one of the important goals in electrical power systems and it is provided by optimal reactive power flow (ORPF). In this study, a new approach for the solution of the ORPF in multiterminal AC-DC systems is proposed. This approach provides 3 main contributions. First, the convergence problem in the AC-DC power flow is solved. Second, the problem of getting stuck in local minima during the optimization process is overcome. Third, a better global optimum point is obtained for the ORPF. Active power loss optimization is implemented through the artificial bee colony (ABC) algorithm, which is …

Go to article

Design And Realization Of A Welding Oscillator, Muci̇z Özcan Jan 2014

Design And Realization Of A Welding Oscillator, Muci̇z Özcan

Turkish Journal of Electrical Engineering and Computer Sciences

Welding is one of the most popular methods to combine metal pieces in manufacturing processes. Arc welding, among all welding techniques, is the most commonly used in manufacturing due to its cost and flexibility. During the manufacturing process, arc welding is either performed by an operator or by automatic tools such as welding oscillators. Using automatic tools has advantages over manual use, as the process will be faster, cheaper, and have less welding flaws. In this paper, a homemade welding oscillator and the method to manufacture it are presented. The presented welding oscillator can be manufactured for a very low …

Go to article

A Reconfigurable Baseband Circuit Applied For Wimax Low-If Receivers, Xin Cheng, Guangjun Xie Jan 2014

A Reconfigurable Baseband Circuit Applied For Wimax Low-If Receivers, Xin Cheng, Guangjun Xie

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a reconfigurable baseband circuit for WiMAX low-IF receivers, including a complex filter and 2 automatic gain controllers (AGCs) for I and Q channels. Only by changing the capacitor values can the center and cutoff frequencies of the complex filter be adjusted simultaneously to realize the reconfigurability. Meanwhile, a novel one-step method to obtain fast gain settling of AGCs is proposed. The chip is fabricated in 0.13-\mu m CMOS technology, occupies 0.9 \times 1.3 mm^2, and consumes 14.8 mW of power with a 1.2-V power supply. The measurement results show a reconfigurable bandwidth of 2 K to 3.5/5/10 …

Go to article

Comparison Of Ais And Fuzzy C-Means Clustering Methods On The Classification Of Breast Cancer And Diabetes Datasets, Seral Özşen, Rahi̇me Ceylan Jan 2014

Comparison Of Ais And Fuzzy C-Means Clustering Methods On The Classification Of Breast Cancer And Diabetes Datasets, Seral Özşen, Rahi̇me Ceylan

Turkish Journal of Electrical Engineering and Computer Sciences

Data reduction is an indispensable part of pattern classification processes in many cases. If the number of samples is excessive, sample reduction or data reduction algorithms can be used for an effective processing time and reliable successive results. Many methods have been used for data reduction. Fuzzy c-means is one of these methods and it is widely used in such applications as clustering algorithms. In this study, we applied a different clustering algorithm, an artificial immune system (AIS), for the data reduction process. We realized the performance evaluation experiments on the standard Chainlink and Iris datasets, while the main application …

Go to article

Predics: A New Go-Po-Based Ray Launching Simulator For The Calculation Of Electromagnetic Scattering And Rcs From Electrically Large And Complex Structures, Caner Özdemi̇r, Betül Yilmaz, Özkan Kirik Jan 2014

Predics: A New Go-Po-Based Ray Launching Simulator For The Calculation Of Electromagnetic Scattering And Rcs From Electrically Large And Complex Structures, Caner Özdemi̇r, Betül Yilmaz, Özkan Kirik

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we present a new simulator called pRediCS for the calculation of electromagnetic scattering and radar cross-section (RCS) from electrically large and complex targets. The simulator utilizes the geometric optics (GO) theory and launching of electromagnetic rays for tracing and calculating the electric field values as the electromagnetic waves bounce around the target. The physical optics (PO) theory is also exploited to calculate the final scattered electric field by calculating the far-field PO integration along the observation direction. The simulator is first tested with known objects of canonical shapes, whose analytical solutions are available in the literature. Next, …

Go to article

Sliding Mode Controller Design With Fractional Order Differentiation: Applications For Unstable Time Delay Systems, Celaleddi̇n Yeroğlu, Gürkan Kavuran Jan 2014

Sliding Mode Controller Design With Fractional Order Differentiation: Applications For Unstable Time Delay Systems, Celaleddi̇n Yeroğlu, Gürkan Kavuran

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a design method for a sliding mode controller with the contribution of a fractional order differential operator. The conventional sliding mode controller has been widely studied in different control applications. This paper proposes that the fractional order differential operator enlarges the output span of the classical sliding mode controller to obtain a better-fitting control signal for enhanced control performance. The sliding surface and the equivalent control law are modified with the addition of a fractional differential operator and a conventional one. The proposed sliding mode controller with fractional order differentiation is applied to the unstable time delay …

Go to article

Abrupt And Incipient Fault Detection And Compensation For A 4-Tank System Benchmark, Pedram Hajiani, Javad Poshtan Jan 2014

Abrupt And Incipient Fault Detection And Compensation For A 4-Tank System Benchmark, Pedram Hajiani, Javad Poshtan

Turkish Journal of Electrical Engineering and Computer Sciences

Fault detection and compensation play a key role in enhancing the high demand for performance and security in technological systems. This paper proposes an active fault-tolerant control scheme that detects and compensates for actuator faults in a 4-tank system benchmark. The faults are modeled as a drastic gain loss in actuators (pumps), which could lead to a large loss in the nominal performance. The model-based approach uses a recursive least squares parameter estimation algorithm to form a fault detection and diagnosis subsystem and utilizes a parametric eigenstructure assignment method to reconfigure the state feedback controller. The designed controller is simulated …

Go to article

Real-Time Control Of An Automated Guided Vehicle Using A Continuous Mode Of Sliding Mode Control, Bi̇rol Soysal Jan 2014

Real-Time Control Of An Automated Guided Vehicle Using A Continuous Mode Of Sliding Mode Control, Bi̇rol Soysal

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a tracking control method for a certain type of differential-drive wheeled mobile robot, called automated guided vehicles (AGVs), using a continuous mode approach of sliding mode control (SMC). The SMC applied produces a continuous signal in between the U and -U control signals instead of discrete ones. The controller is applied to control the velocity and direction angle of the vehicle in order to keep it on a desired path. The obtained algorithm is applied to the experimental system under load and disturbance to show its robustness. The experimental results are satisfactory and verify the performance of …

Go to article

Horizontal Dilution Of Precision-Based Ultra-Wideband Positioning Technique For Indoor Environments, Kerem Küçük Jan 2014

Horizontal Dilution Of Precision-Based Ultra-Wideband Positioning Technique For Indoor Environments, Kerem Küçük

Turkish Journal of Electrical Engineering and Computer Sciences

Ultra-wideband (UWB) technology provides considerable performance in many indoor localization problems thanks to its very wide spectrum and high-resolution characteristics. In this paper, we propose using the horizontal dilution of precision (HDOP) to decrease the localization error in indoor environments for UWB localization systems. To achieve this aim, first we determine the positioning accuracy of a commercially available UWB positioning system using laboratory experiments. Next, the results of the position estimations obtained by the HDOP are compared with the experimental results acquired by the UWB positioning system. Finally, we investigate a detailed comparison with the least squares (LS), nonlinear regression …

Go to article

Comparative Learning Global Particle Swarm Optimization For Optimal Distributed Generations' Output, Jasrul Jamani Jamian, Hazlie Mokhlis, Mohd Wazir Mustafa, Mohd Noor Abdullah, Muhammad Ariff Baharuddin Jan 2014

Comparative Learning Global Particle Swarm Optimization For Optimal Distributed Generations' Output, Jasrul Jamani Jamian, Hazlie Mokhlis, Mohd Wazir Mustafa, Mohd Noor Abdullah, Muhammad Ariff Baharuddin

Turkish Journal of Electrical Engineering and Computer Sciences

The appropriate output of distributed generation (DG) in a distribution network is important for maximizing the benefit of the DG installation in the network. Therefore, most researchers have concentrated on the optimization technique to compute the optimal DG value. In this paper, the comparative learning in global particle swarm optimization (CLGPSO) method is introduced. The implementation of individual cognitive and social acceleration coefficient values for each particle and a new fourth term in the velocity formula make the process of convergence faster. This new algorithm is tested on 6 standard mathematical test functions and a 33-bus distribution system. The performance …

Go to article

Solving A New Bi-Objective Joint Replenishment Inventory Model With Modified Rand And Genetic Algorithms, Ommolbanin Yousefi, Seyed Jafar Sadjadi Jan 2014

Solving A New Bi-Objective Joint Replenishment Inventory Model With Modified Rand And Genetic Algorithms, Ommolbanin Yousefi, Seyed Jafar Sadjadi

Turkish Journal of Electrical Engineering and Computer Sciences

There are many cases in real inventory systems where more than one objective must be optimized. The main purpose of this research is to develop a multiobjective joint replenishment problem (JRP), where one objective is the minimization of the total inventory investment and another is the minimization of the total inventory ordering and holding costs. To solve the suggested model, 3 algorithms are proposed. In the first algorithm, the existing RAND method, called the best heuristic for solving the JRP, is modified and a new heuristic algorithm is developed to be applicable to the JRP with 2 objectives. The second …

Go to article

A New Approach Of Nonblind Watermarking Methods Based On Dwt And Svd Via Lu Decomposition, Onur Jane, Ersi̇n Elbaşi Jan 2014

A New Approach Of Nonblind Watermarking Methods Based On Dwt And Svd Via Lu Decomposition, Onur Jane, Ersi̇n Elbaşi

Turkish Journal of Electrical Engineering and Computer Sciences

Multimedia security has been the focal point of considerable research activity in the last decade, mainly because of its wide application area. Watermarking, in particular, is identified as a major technology to achieve copyright protection and multimedia security. Therefore, recent studies in the literature include some evident approaches for embedding data into a multimedia element. Because of its useful frequency component separation, the discrete wavelet transform (DWT) is commonly used in watermarking schemes. Moreover, singular value decomposition (SVD) and lower-and-upper (LU) decomposition have little effect on the perception of the watermark. Therefore, in this study, a combination of DWT and …

Go to article

Implementation Of Neural Network-Based Maximum Power Tracking Control For Wind Turbine Generators, Abdulhaki̇m Karakaya, Ercüment Karakaş Jan 2014

Implementation Of Neural Network-Based Maximum Power Tracking Control For Wind Turbine Generators, Abdulhaki̇m Karakaya, Ercüment Karakaş

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, the maximum power point tracking (MPPT) of a permanent magnet synchronous generator used in a wind generator system is realized by a prototype installed in a laboratory environment. The installed prototype is modeled in a MATLAB/Simulink environment. The MPPT is realized by an artificial neural network (ANN). The obtained simulation and experimental results are compared. The maximum power estimation at various windmill speeds (rpm) of the trained ANN in determined reference speeds is analyzed. The zero crossing points of the phases are determined by a digital signal peripheral interface controller and the system is operated according to …

Go to article

Face Recognition Across Pose Variation And The 3s Problem, Jamal Hussain Shah, Muhammad Sharif, Mudassar Raza, Aisha Azeem Jan 2014

Face Recognition Across Pose Variation And The 3s Problem, Jamal Hussain Shah, Muhammad Sharif, Mudassar Raza, Aisha Azeem

Turkish Journal of Electrical Engineering and Computer Sciences

Most face recognition methods are based on linear and nonlinear subspace features extraction and classification tasks. These classification methods are used for global and local facial features for person identification. Both local and global features play different roles for recognition and classification. There are a number of face recognition methods that have been proposed up until now, and they produce good results. However, when small sample size (3S) and pose variation problems are taken into consideration, face recognition becomes more complex and does not produce good results. In this paper, 3S and pose variation problems are dealt with. First, linear …

Go to article

The Design Of An Embedded Spinal Cord Stimulator, Fi̇kret Yalçinkaya, Ali̇ Erbaş Jan 2014

The Design Of An Embedded Spinal Cord Stimulator, Fi̇kret Yalçinkaya, Ali̇ Erbaş

Turkish Journal of Electrical Engineering and Computer Sciences

Spinal cord stimulation is a physical therapy methodology utilizing electrical impulses, pulses, or a combination of various standard electrical waveforms to block pain. However, standard forms are not functioning effectively for each illness due to the unique conditions of the patient. Therefore, patient-specific waveforms (or user-defined waveforms) integrated with nondestructive, complete, or partially noninvasive and effective medical instruments to help relieve pain are required. In the literature, 2 different designs have been discussed: the bedside/portable and the implantable/surgical types. This work is introducing a new hybrid type: a portable touch-screen multichannel embedded spinal cord stimulator. This work is made of …

Go to article

Enhancing Agility Of Supply Chains Using Stochastic, Discrete Event And Physical Simulation Models, Alok K. Verma Jan 2014

Enhancing Agility Of Supply Chains Using Stochastic, Discrete Event And Physical Simulation Models, Alok K. Verma

Engineering Technology Faculty Publications

Managing supply chains in today’s distributed manufacturing environment has become more complex. To remain competitive in today’s global marketplace, organizations must streamline their supply chains. The practice of coordinating the design, procurement, flow of goods, services, information and finances, from raw material flows to parts supplier to manufacturer to distributor to retailer and finally to consumer requires synchronized planning and execution. Efficient and effective supply chain management assists an organization in getting the right goods and services to the place needed at the right time, in the proper quantity and at acceptable cost. Managing this process involves developing and overseeing …

Go to article

Intelligent Sensing Based On Low Cost Unmanned Aerial Vehicles (Uav) For Bridge Condition Assessment, Theodore Teates, Austin Boyd, Chung-Hao Chen Jan 2014

Intelligent Sensing Based On Low Cost Unmanned Aerial Vehicles (Uav) For Bridge Condition Assessment, Theodore Teates, Austin Boyd, Chung-Hao Chen

Electrical & Computer Engineering Faculty Publications

The eventual completion of this project envisions the use of an Unmanned Aerial Vehicle (UAV) to inspect bridge infrastructure. This project may also be expanded to encompass general object detection and inspection in order to unburden this technology so that it may reach its fullest potential. The project requires research and development in three distinct areas of image processing, control structures, and integration of systems. Initial undergraduate research sets the base knowledge for the overall project, explores the areas of concentration that are desired to expand upon in the future project, and provides a base UAV model that new researchers …

Go to article

Mathematical Methods Applied To Digital Image Processing, Yi-Hung Liu, Chung Hao Chen, Paul C.P. Chao Jan 2014

Mathematical Methods Applied To Digital Image Processing, Yi-Hung Liu, Chung Hao Chen, Paul C.P. Chao

Electrical & Computer Engineering Faculty Publications

Introduction: Digital image processing (DIP) is an important research area since it spans a variety of applications. Although over the past few decades there has been a rapid rise in this field, there still remain issues to address. Examples include image coding, image restoration, 3D image processing, feature extraction and analysis, moving object detection, and face recognition. To deal with these issues, the use of sophisticated and robust mathematical algorithms plays a crucial role. The aim of this special issue is to provide an opportunity for researchers to publish their latest theoretical and technological achievements in mathematical methods and their …

Go to article

Stability Of High Band Gap P3ht: Pcbm Organic Solar Cells Using Tiox Interfacial Layer, Kurniawan Foe, Gon Namkoong, Matthew Samson, Enas M. Younes, Ilho Nam, Tarek M. Abdel-Fattah Jan 2014

Stability Of High Band Gap P3ht: Pcbm Organic Solar Cells Using Tiox Interfacial Layer, Kurniawan Foe, Gon Namkoong, Matthew Samson, Enas M. Younes, Ilho Nam, Tarek M. Abdel-Fattah

Electrical & Computer Engineering Faculty Publications

We fabricated a poly [3-hexylthiophene] (P3HT) and [6,6] -phenyl-C61-butyric acid methyl ester (PC61BM with the TiOx layer. We found that a solution based TiOx coated at a spin speed of 3000 rpm improved the photon absorption of the active layer. An optimized TiOx layer was also used as the interfacial layer to investigate the stability of P3HT: PC61BM OPC. After 70 days of storage, we observed that the short-circuit current density (JSC) dropped by 16.2%, fill factor (FF) dropped by 10.6%, and power conversion efficiency (PCE) dropped approximately by 25%, while …

Go to article

Measurement Of Working, Reflected, And Detrimental Active Power In A Three Phase System, Tracy Toups Jan 2014

Measurement Of Working, Reflected, And Detrimental Active Power In A Three Phase System, Tracy Toups

LSU Doctoral Dissertations

Study of the decomposition of the active power into composite components with respects to power industry economics namely, working active power, reflected active power, and detrimental active power. The working active energy is considered the permanent flow of useful energy to the load that results in deliberate heat, lighting, or torque on the motor shaft. The reflected active energy is the extra component of active energy originating from the load and dissipates on the supply impedance that does not contribute to useful energy. Lastly, detrimental active energy is the flow of harmonic energy from the supply to the load due …

Go to article

Influence Of Magnetic Fields On The Evaporation And Combustion Of A Single Droplet, Domingo Elias Jan 2014

Influence Of Magnetic Fields On The Evaporation And Combustion Of A Single Droplet, Domingo Elias

LSU Master's Theses

The reliance on combustion as the primary source of energy will continue in the US for the next thirty years [1]. Experiments suggest that the use of magnetic fields can be one tool in the many-sided approach to the problem of environmental protection and energy conservation in the US. For instance, it is estimated that an increase in efficiency of 2% in spray combustion can save the US economy billions of dollars [2]. In this thesis I report on improving the quality of combustion through the use of magnetic fields. (1)I investigated the effects of magnetic fields on the evaporation …

Go to article

A Study Of Induction Pyrolysis Of Lignicellulosic Biomass For The Production Of Bio-Oil, Charles Edward Henkel Jan 2014

A Study Of Induction Pyrolysis Of Lignicellulosic Biomass For The Production Of Bio-Oil, Charles Edward Henkel

LSU Master's Theses

The increasing demand for energy coupled with a growing concern that the combustion of fossil fuels has on the environment, through the production of greenhouse gases, has created a demand for renewable energy sources. The demand for renewable energy, particularly liquid transportation fuels, can be met in part by the use of biomass based liquid fuels. There are several methods that can be used to produce biomass based fuels, but only thermochemical conversion (pyrolysis) can readily convert lignocellulosic biomass into a fuel-like liquid, bio-oil. The pyrolytic conditions for obtaining maximum liquid yields vary, but many of the criteria can be …

Go to article

Silver Nanoparticle Oligonucleotide Conjugate For Targeted Gene Silencing, Alyson Nanette Moll Jan 2014

Silver Nanoparticle Oligonucleotide Conjugate For Targeted Gene Silencing, Alyson Nanette Moll

LSU Master's Theses

This project explored a gene-regulated chemotherapy using a silver nanoparticle (SNP) conjugated with deoxyribozyme (DNAzyme) oligonucleotides which target a mutated gene in select cancer cells, sensitize them to doxorubicin treatment. Light exposure to the SNP-DNAzyme conjugates disengages the oligonucleotides and permits specific cleavage of the Kirsten Rat Sarcomal Oncogene Homolog (K-RAS) mRNA. These conjugates could provide spatiotemporal specificity in killing only those photoexposed cells with the mutant gene. Synthesis, functionalization and characterization of citrate and hydroxypropyl cellulose SNP conjugates confirmed attachment and photolytic release of the thiol-modified 10-23 DNAzyme. Gel electrophoresis was used to demonstrate DNAzyme photoactivation, showing greater K-RAS …

Go to article

Analysis Of Hydrodynamic Drag Forces Acting On Suspended Fine Particle In Porous Media, Seyed Amin Mirsaeidi Farahani Jan 2014

Analysis Of Hydrodynamic Drag Forces Acting On Suspended Fine Particle In Porous Media, Seyed Amin Mirsaeidi Farahani

LSU Doctoral Dissertations

An important class of flow and transport problems occurring in porous media involves the interactions between suspended fine particles and the moving fluid at Stokes limit. Historically, due to the complicated geometries of porous media, researchers have had to resort to simplifying assumptions to conceptualize the underlying physics. However, the advent of high performance computing, in recent decades, has made it possible to vigorously investigate this problem at the streamline scale level. In this work, the flow problem is solved by means of a finite-element model. The simulations results are used to compute the drag forces experienced by suspended fine …

Go to article

Power System Differential Model With Application To Grid Dynamic Simulation, Boyu Wang Jan 2014

Power System Differential Model With Application To Grid Dynamic Simulation, Boyu Wang

LSU Master's Theses

Nonlinearity of power system is always one of the difficulties when dealing with dynamic simulation of power systems. Solving differential-algebraic equations representing power systems are difficult without losing nonlinearity, especially for large power systems. This thesis shows an alternative method to solve nonlinear dynamical power system by producing a purely differential representation of the power systems. This new representation converts the algebraic equations to differential equations in order to have an absolute differential system. By using Runge-Kutta algorithm to solve this differential system, the results of the power system simulations are compared to trapezoidal integration algorithm commonly used to solve …

Go to article

Innovative Heat Transfer Augmentation Techniques In Mechanical Face Seal, Nian Xiao Jan 2014

Innovative Heat Transfer Augmentation Techniques In Mechanical Face Seal, Nian Xiao

LSU Doctoral Dissertations

Excessive heat generated at the face seal contact interface has been recognized as one of main causes of failure of mechanical seals. In the past few decades various efforts have been attempted to remove heat from the contact interface uniformly in order to reduce the interfacial temperature, eliminate thermally-induced failure, and thus increase the life of a mechanical seal. Two innovative heat transfer augmentation techniques - surface texturing and built-in phase change device - have been developed in our laboratory to effectively enhance the heat transfer in mechanical face seal. Surface texturing can increase the surface area, change the near …

Go to article

Timoshenko Beam Model For Lateral Vibration Of Liquid-Phase Microcantilever-Based Sensors, Joshua A. Schultz, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour, Nicholas J. Nigro, Luke A. Beardslee, Oliver Brand Jan 2014

Timoshenko Beam Model For Lateral Vibration Of Liquid-Phase Microcantilever-Based Sensors, Joshua A. Schultz, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour, Nicholas J. Nigro, Luke A. Beardslee, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

Dynamic-mode microcantilever-based devices are potentially well suited to biological and chemical sensing applications. However, when these applications involve liquid-phase detection, fluid-induced dissipative forces can significantly impair device performance. Recent experimental and analytical research has shown that higher in-fluid quality factors (Q) are achieved by exciting microcantilevers in the lateral flexural mode. However, experimental results show that, for microcantilevers having larger width-to-length ratios, the behaviors predicted by current analytical models differ from measurements. To more accurately model microcantilever resonant behavior in viscous fluids and to improve understanding of lateral-mode sensor performance, a new analytical model is developed, incorporating both …

Go to article

Low Frequency Improvements To Commercial Geophones, Brian Michael Holden Jan 2014

Low Frequency Improvements To Commercial Geophones, Brian Michael Holden

LSU Master's Theses

Commercial geophones have been used in the field of geology for many years. They are commonly used to detect oil and gas deposits and create three dimensional simulations of the earth. Geophones are commonly made up of a spring mounted magnetic mass moving back and forth in a wire coil to create a voltage. The response of the coil is proportional to the velocity of the ground. At various frequencies, seismic events can be measured using a geophone. However, most commercial geophones only allow accurate measurements of frequencies down to approximately five hertz. By using a feedback circuit, an attempt …

Go to article

Analysis Of Microseismic Events Associated With Hydraulic Fracture Propagation, Chennu Fan Jan 2014

Analysis Of Microseismic Events Associated With Hydraulic Fracture Propagation, Chennu Fan

LSU Master's Theses

Previous practice to determine the source mechanism of microseismic events associated with hydraulic fracture typically includes only far-field terms in moment tensor inversion. The intermediate-field terms and near-field term are normally ignored because of increased complexity in the calculation. Source-receiver distances in hydraulic fracturing are usually 1000 ft and the effects of near and intermediate-field terms are still unknown. We perform a study to improve the precision of the source mechanism by including the intermediate-field term in moment tensor inversion. We find that the intermediate-field term contributes 1/3 of the signal amplitude when the source-receiver distance is 1000 ft. The …

Go to article

Advanced And Novel Modeling Techniques For Simulation, Optimization And Monitoring Chemical Engineering Tasks With Refinery And Petrochemical Unit Applications, Gregory M. Robertson Jan 2014

Advanced And Novel Modeling Techniques For Simulation, Optimization And Monitoring Chemical Engineering Tasks With Refinery And Petrochemical Unit Applications, Gregory M. Robertson

LSU Doctoral Dissertations

Engineers predict, optimize, and monitor processes to improve safety and profitability. Models automate these tasks and determine precise solutions. This research studies and applies advanced and novel modeling techniques to automate and aid engineering decision-making. Advancements in computational ability have improved modeling software’s ability to mimic industrial problems. Simulations are increasingly used to explore new operating regimes and design new processes. In this work, we present a methodology for creating structured mathematical models, useful tips to simplify models, and a novel repair method to improve convergence by populating quality initial conditions for the simulation’s solver. A crude oil refinery application …

Go to article

First Prev Next Last