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LSU Doctoral Dissertations

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Full-Text Articles in Engineering Science and Materials

Analysis And Management Of The Price Volatility In The Construction Industry, Alireza Joukar Jan 2016

Analysis And Management Of The Price Volatility In The Construction Industry, Alireza Joukar

LSU Doctoral Dissertations

The problem of price volatility as it pertains to material and labor is a major source of risk and financial distress for all the participants in the construction industry. The overarching goal of this dissertation is to address this problem from both viewpoints of risk analysis and risk management. This dissertation offers three independent papers addressing this goal. In the first paper using the Engineering News Record Construction Cost Index (ENR CCI), a predictive model is developed. The model uses General Autoregressive Conditional Heteroscedastic (GARCH) approach which facilitates both forecasting of the future values of the CCI, and capturing and …


Numerical Simulations Of Wind Effects On Wave Nonlinearity And Hurricane-Induced Sediment Transport On Louisiana Coast, Ke Liu Jan 2016

Numerical Simulations Of Wind Effects On Wave Nonlinearity And Hurricane-Induced Sediment Transport On Louisiana Coast, Ke Liu

LSU Doctoral Dissertations

The objective of this study is to model wind effects on wave nonlinearity and the sediment suspension, transport and redistribution caused by hurricanes. The following questions are addressed through numerical simulations: (1) How do winds affect wave triad interactions and wave shape in the shallow water? (2) What is the role of hurricanes in coastal landscape evolution? Do they create more erosion or deposition? (3) Where does the observed post-hurricane deposition on coastal wetlands come from? First, wind effects were incorporated into a Boussinesq-type wave model, and evolution equations were derived for triad interactions with winds. Second, a coupled modeling …


Production Of Fermentable Sugars From Energy Cane Bagasse, Saeed Oladi Jan 2016

Production Of Fermentable Sugars From Energy Cane Bagasse, Saeed Oladi

LSU Doctoral Dissertations

Lignocellulosic biomass contains cellulose and hemicellulose which are composed of hexose and pentose sugars. These sugars can be used in the sustainable production of fuels and chemicals. However, the recalcitrant nature of lignocellulosic biomass makes this conversion a challenging process. An effective pretreatment can remove lignin, solubilize the hemicellulose, decrease cellulose crystallinity, and prepare the biomass for enzymatic hydrolysis and conversion into green renewable chemicals. The research study presented in this dissertation addressed some of the challenges associated with the conversion of lignocellulosic biomass into green fuels and chemicals. This study was divided into three main goals. The first goal …


Automated Generation And Visualization Of Initial Construction Schedules From Building Information Models, Yibrah Weldemihret Weldu Jan 2016

Automated Generation And Visualization Of Initial Construction Schedules From Building Information Models, Yibrah Weldemihret Weldu

LSU Doctoral Dissertations

Recent advances in digital technology have had a significant influence on the quality and speed of sharing and communicating project information in the architecture, engineering, and construction (AEC) industry. The process of acquiring the design intent in order to develop and communicate project schedules, as critical components of project delivery, have similarly been benefitting from such progress. With the relatively recent techniques of Building Information Modeling (BIM) and its capability to integrate the facility design with its construction schedule, meaningul strides have been made in improving the information flow and eventually visualizing the final schedule in 4D. However, the need …


Thermo-Catalytic Upgrading Of Pyrolysis Vapors Using Electromagnetic Heating, Pranjali Devidas Muley Jan 2015

Thermo-Catalytic Upgrading Of Pyrolysis Vapors Using Electromagnetic Heating, Pranjali Devidas Muley

LSU Doctoral Dissertations

Electromagnetic heating offers several advantages such as rapid heating rates, accurate temperature control and energy efficiency over conventional reactors. The goal of this study was to design an effective and energy efficient catalytic reactor for pyrolysis vapor upgrading. An induction based catalytic reactor was designed for upgrading of pyrolysis vapors. The effect of catalyst bed temperatures (290°, 330° and 370°C) and biomass to catalyst ratios of 1, 1.5 and 2 was studied. The results were compared to conventional heating reactor. Induction heating reactor performance exceeded that of conventional heater. The biomass to catalyst ratio of 2 in combination with the …


Time-Resolved Investigations Of Continuous Flow Synthesis Of Nanomaterials And Catalysis Using Millifluidic Reactors For Biomass Conversion Reactors, Chelliah V Navin Jan 2015

Time-Resolved Investigations Of Continuous Flow Synthesis Of Nanomaterials And Catalysis Using Millifluidic Reactors For Biomass Conversion Reactors, Chelliah V Navin

LSU Doctoral Dissertations

Millifluidics can be used as a simple tool and convenient platform to perform in-situ investigations on nanoparticles synthesis to generate real-time information in a continuous flow fashion. These investigations can be used to observe the relationship between the structure and performance of nanoparticles for catalytic applications as a function of space and time. These improvements in nanoparticles research offer unique advantages to develop catalysts with molecular strategies. In order to showcase these advantages of the millifluidic reactors, here we: A. Extensively covered a complete literature review on Lab-on-a-chip devices for gold nanoparticle synthesis and as a catalyst support for continuous …


Constitutive Modeling And Experiments For The Micro And Nano Behaviors In Metals, Cheng Zhang Jan 2015

Constitutive Modeling And Experiments For The Micro And Nano Behaviors In Metals, Cheng Zhang

LSU Doctoral Dissertations

This work addresses the micro- and nano-behaviors in metals through constitutive modeling and experiments. The size effect encountered during nanoindentation experiments, which is known as indentation size effect (ISE), is investigated for metal materials. The ISE is believed to be related with the strain gradient at small indentation depths. Geometrically necessary dislocations (GNDs) are formed in order to accommodate the strain gradient, which results in the increase in the material hardness. The grain boundaries in polycrystalline materials play an important role on the material hardness during nanoindentation experiments as there is a soften-hardening segment in the curve of hardness as …


Integrated Sustainability And Resiliency Assessment Methodology For The Design Of Single-Family Residential Structures Subject To Wind And Flood Hazards, Elizabeth Chisolm Matthews Jan 2015

Integrated Sustainability And Resiliency Assessment Methodology For The Design Of Single-Family Residential Structures Subject To Wind And Flood Hazards, Elizabeth Chisolm Matthews

LSU Doctoral Dissertations

Sustainability and resiliency have become important in shaping the criteria in performance-based design objectives in the recent past and will continue to shape future design as climate change impacts and disasters become more prevalent. While much work has been carried out in developing tools to aid in sustainable and resilient performance-based design there is still much work to be done. It is evident that while sustainability and resiliency have mutual advantages there are also inherent conflicts between the two design approaches. Some of the conflict relates to the robustness required of resilient design, which may have higher environmental impacts than …


Interorganizational Collaboration And Systemic Change Framework For Building Information Modeling (Bim) Adoption, Rehema Joseph Monko Jan 2015

Interorganizational Collaboration And Systemic Change Framework For Building Information Modeling (Bim) Adoption, Rehema Joseph Monko

LSU Doctoral Dissertations

It was found that an integrated framework needs to be developed for the construction industry that allows optimized interorganizational collaboration and systemic change while using Building Information Modeling (BIM) technologies. The framework needs to be effective so the industry can adopt BIM through a set of interdependent activities beyond their organizational boundaries. The adoption has been proven difficult because of industry competitiveness and a fragmented work environment. Meanwhile, existing frameworks vary between studies. This research developed an integrated framework, identified critical factors, and provided an evaluation guide for interorganizational collaboration and set of coordinated changes necessary to adopt BIM. This …


Product Parameters Optimization For Double Purge Of C-Magma Integrated With Conventional Three-Boiling Crystallization Scheme To Improve Raw Sugar Whole Color, Luz Stella Polanco Jan 2015

Product Parameters Optimization For Double Purge Of C-Magma Integrated With Conventional Three-Boiling Crystallization Scheme To Improve Raw Sugar Whole Color, Luz Stella Polanco

LSU Doctoral Dissertations

Efficient crystallization in raw sugar production is the result of a combination of factors and responses that meet specific criteria. Matching a sugar quality standard, maximizing sugar yield, maximizing crystallization equipment capacity and minimizing heat requirement are all necessary optimization criteria. A double centrifugation or purge of C-magma is intended to improve raw sugar whole color by the reduction of color recirculation with the sugar crystal. Combining a three boiling crystallization scheme with a second centrifugation after the last crystallization stage required optimizing the input/output product parameters (purities) and the location of the liquid recycle component (double purge molasses) for …


Thiol-Ene Scaffolds As Synthetic Augments And Silicate Ceramics As Osteogenic Components For Bone Tissue Engineering Applications, Cong Chen Jan 2015

Thiol-Ene Scaffolds As Synthetic Augments And Silicate Ceramics As Osteogenic Components For Bone Tissue Engineering Applications, Cong Chen

LSU Doctoral Dissertations

Bone tissue engineering approaches using polymer/ceramic composites show promise as effective biocompatible, absorbable, and osteoinductive materials. A novel class of in situ polymerizing thiol-acrylate based copolymers synthesized via an amine-catalyzed Michael addition was studied for its potential to be used in bone defect repair. Both pentaerythritol triacrylate-co-trimethylolpropane tris(3-mercaptopropionate) (PETA-co-TMPTMP) and PETA-co-TMPTMP with hydroxyapatite composites were fabricated in solid cast and foamed forms. These materials were characterized chemically and mechanically followed by an in vitro evaluation of the biocompatibility and chemical stability in conjunction with human adipose-derived mesenchymal pluripotent stem cells (hASC). The solid PETA-co-TMPTMP with and without hydroxyapatite (HA) exhibited …


Context Aware Textual Entailment, Soha Arab-Khazaeli Jan 2015

Context Aware Textual Entailment, Soha Arab-Khazaeli

LSU Doctoral Dissertations

In conversations, stories, news reporting, and other forms of natural language, understanding requires participants to make assumptions (hypothesis) based on background knowledge, a process called entailment. These assumptions may then be supported, contradicted, or refined as a conversation or story progresses and additional facts become known and context changes. It is often the case that we do not know an aspect of the story with certainty but rather believe it to be the case; i.e., what we know is associated with uncertainty or ambiguity. In this research a method has been developed to identify different contexts of the input raw …


Risk-Based Wind Loss And Mitigation For Residential Wood Framed Construction, Fatemeh Orooji Jan 2015

Risk-Based Wind Loss And Mitigation For Residential Wood Framed Construction, Fatemeh Orooji

LSU Doctoral Dissertations

As a result of increasing windstorm losses in the United States over the past 50 years, a variety of residential wind hazard mitigation methods have been suggested. Mitigation undoubtedly reduces windstorm losses; however, the expected economic risk reduction of mitigation practices over the life of the building depends on the building characteristics (i.e., capacity) and the intensity and occurrence of wind speeds (i.e., demand). Effective decision making requires estimation of potential future losses based on many variables. Many models, primarily mechanics-based simulation models, have been developed to predict building damage from wind events; however; fewer models of economic loss have …


Image-Based Modeling Of Porous Media Using Fem And Lagrangian Particle Tracking, Paula Cysneiros Sanematsu Jan 2015

Image-Based Modeling Of Porous Media Using Fem And Lagrangian Particle Tracking, Paula Cysneiros Sanematsu

LSU Doctoral Dissertations

The study of fundamental flow and transport processes at the pore scale is essential to understanding how the mechanisms affect larger, field-scale, processes that occur in oil and gas recovery, groundwater flow, contaminant transport, and CO2 sequestration. Pore-scale imaging and modeling is one of the techniques used to investigate these fundamental mechanisms. Although extensive development of pore-scale imaging and modeling has occurred recently, some areas still need further advances. In this work, we address two areas: (1) imaging of bulk proppants and proppant-filled fractures under varying loading stress and flow simulation in these systems and (2) nanoparticle (NP) transport modeling …


Developing Co-Current And Counter-Current Spray Drying Computational Fluid Dynamics (Cfd) Simulation Studies To Predict The Quality Of Microencapsulated Fish Oil With Egg White Hydrolysates Powders, Kevin Estuardo Mis Solval Jan 2015

Developing Co-Current And Counter-Current Spray Drying Computational Fluid Dynamics (Cfd) Simulation Studies To Predict The Quality Of Microencapsulated Fish Oil With Egg White Hydrolysates Powders, Kevin Estuardo Mis Solval

LSU Doctoral Dissertations

Eggs are an excellent source of high quality protein containing all essential amino acids (EAA) including leucine. Food-grade protein hydrolysates can enhance the growth of lactic acid bacteria (LAB). Thermal degradation of bioactives normally occurs during microencapsulation by spray drying. Spray drying modeling using computational tools is essential to engineer new food powders and to minimize and thermal degradation of bioactives. The first chapter of this work discusses the optimization of an enzymatic process in terms of reaction temperature, pH, enzyme:substrate ratio, and reaction time using a response surface methodology (RSM) to produce food-grade protein hydrolysates from egg whites (EWH). …


Release, Stability And Functionality Of Nanodelivered Hydrophobic (Lutein And Beta-Carotene) And Hydrophilic (Folic Acid) Antioxidants Using Zein Nanoparticles, Thanida Chuacharoen Jan 2015

Release, Stability And Functionality Of Nanodelivered Hydrophobic (Lutein And Beta-Carotene) And Hydrophilic (Folic Acid) Antioxidants Using Zein Nanoparticles, Thanida Chuacharoen

LSU Doctoral Dissertations

Nanodelivery systems enable innovations that can benefit foods and human health on a large scale in the coming years. The instabilities of antioxidants during food processing and during digestion are drawbacks that can be successfully addressed by nanoentrapment. This research provided technical strategies to synthesize zein nanoparticles loaded with hydrophobic/hydrophilic antioxidants, and to study the release profiles and physical stability of nanocarriers and chemical stability of entrapped bioactives under on-shelf and GI conditions. The results supported the potential of zein nanoparticles stabilized by surfactants to improve chemical stability of entrapped lutein, and to slowly release lutein under PBS conditions. Same …


Optimal Location Of Biomethane Gas Manufacturing Plants And Allocation Of Feedstock And Liquified Carbon Product, Bingqing Wu Jan 2015

Optimal Location Of Biomethane Gas Manufacturing Plants And Allocation Of Feedstock And Liquified Carbon Product, Bingqing Wu

LSU Doctoral Dissertations

Biomethane gas (BMG), known for its sustainability, low environmental impact, and high profitability, has received wide attention in recent years. To facilitate the process of making strategic plans for building a BMG production system, this dissertation leverages the mathematical modeling and optimization techniques to minimize the supply chain cost for such a system. Typical elements in a BMG production system consist of the local farms that produce the feedstock, the hubs that collect and store the feedstock produced by farms, the reactors that generate BMG from the feedstock transported from the hubs, the condensers that liquefy the BMG from the …


Synthesis And Characterization Of Novel Polyester Scaffolds From Sugarcane Industry By-Products For Use In Skin And Bone Tissue Engineering, Akanksha Kanitkar Jan 2014

Synthesis And Characterization Of Novel Polyester Scaffolds From Sugarcane Industry By-Products For Use In Skin And Bone Tissue Engineering, Akanksha Kanitkar

LSU Doctoral Dissertations

The aim of this work was to synthesize non-toxic, biodegradable polyesters of aconitic acid, cinnamic acid and glycerol from by-products of the sugarcane industry as scaffolds for skin and bone tissue engineering. Utilizing the by-products, molasses and sugarcane bagasse, not only add value to the cane industry, but also paves path for synthesizing novel bio-based materials from the isolated specialty chemicals. Molasses contain an economically recoverable quantity of aconitic acid and its extraction was studied in detail as a part of this work. The yields of recovered aconitic acid varied from 25–69% depending on the extraction conditions. Under all the …


A Metaheuristic-Based Simulation Optimization Framework For Supply Chain Inventory Management Under Uncertainty, Qinglin Duan Jan 2013

A Metaheuristic-Based Simulation Optimization Framework For Supply Chain Inventory Management Under Uncertainty, Qinglin Duan

LSU Doctoral Dissertations

The need for inventory control models for practical real-world applications is growing with the global expansion of supply chains. The widely used traditional optimization procedures usually require an explicit mathematical model formulated based on some assumptions. The validity of such models and approaches for real world applications depend greatly upon whether the assumptions made match closely with the reality. The use of meta-heuristics, as opposed to a traditional method, does not require such assumptions and has allowed more realistic modeling of the inventory control system and its solution. In this dissertation, a metaheuristic-based simulation optimization framework is developed for supply …


Quantification Of The Environmental Impact Of Titanium Dioxide Photocatalytic Pavements For Air Pollution Remediation, Heather Lee Dylla Jan 2013

Quantification Of The Environmental Impact Of Titanium Dioxide Photocatalytic Pavements For Air Pollution Remediation, Heather Lee Dylla

LSU Doctoral Dissertations

Photocatalytic concrete pavements are a promising technology for mobile source air pollution remediation, however before widespread application of this technology is realized many unanswered questions remain regarding its overall environmental impact. In response to these questions, the goal of this study was to increase the understanding of the environmental impact of photocatalytic concrete pavement highways. To achieve this goal, the objectives of this study were to (A) construct a model that evaluates the nitrogen oxides (NOx) reduction from photocatalytic pavements, (B) quantify the nitrates released from the photocatalytic degradation of NOx, and (C) identify and characterize pathways for TiO2 nanoparticle …


Designing A Cost Effective Microalgae Harvesting Strategy For Biodiesel Production With Electrocoagulation And Dissolved Air Flotation, Adam James Dassey Jan 2013

Designing A Cost Effective Microalgae Harvesting Strategy For Biodiesel Production With Electrocoagulation And Dissolved Air Flotation, Adam James Dassey

LSU Doctoral Dissertations

Microalgal harvesting strategies for biodiesel production have been a major setback in the industry with high energy estimates of $3400/ton biomass by centrifugation. The present study utilized effective mass and energy balances to reduce these large operating costs. The energy for Stage 1 centrifugation was reduced by 82% when harvesting 28.5% of biomass at 18 L/min as opposed to 95% harvesting at 1 L/min. This strategy was further confirmed using electrocoagulation (EC) with Nannochloris and Dunaliella algae with perforated aluminum and iron electrodes at low (< 6 mg/L) metal ion concentrations. Despite 20% lower harvesting efficiencies, the iron electrodes were more energy and cost efficient with operating costs less than $0.03/L oil when flocculating and settling Nannochloris and Dunaliella cultures. Furthermore, a continuous multistage algae harvester using EC and dissolved air flotation (DAF) for Stage 1 harvesting and centrifugation for Stage 2 dewatering was designed. It was determined throughout the testing that greater EC costs for improved harvesting efficiencies were necessary to offset the large energy requirements of the DAF. The multistage system dewatered a low density (100 mg/L) Nannochloris to 20% solids for a final energy requirement of 1.536 kWh/kg algae ($138/ton). Using the data collected from this research and existing literature, a life cycle analysis was assembled to judge the sustainability of microalgal biofuels in Louisiana. High and low energy estimates for culturing (mixing, CO2, nutrients), harvesting, lipid extraction and energy conversion were compared with the current research. Scaling the EC/DAF system for a full size facility was expected to reduce the harvesting costs to 1.133 kWh/kg algae, resulting as $0.44/L oil for a culture with 20% lipids. Despite this improvement in harvesting costs, the production of algal for the sole purpose of biodiesel was not economically viable. Considering a system with a growth rate of 15 g/m2/day and lipid content of 20%, the energy inputs exceeded the outputs from biodiesel production by 36% under the most ideal conditions. However, incorporating additional revenue through wastewater treatment and biogas production from residual biomass could improve sustainability and profitability of algal biodiesel to an 18.5% energy surplus at its current state.


Optimal Consignment Stocking Policies For A Supply Chain Under Different System Constraints, Hui Zhi Yi Jan 2013

Optimal Consignment Stocking Policies For A Supply Chain Under Different System Constraints, Hui Zhi Yi

LSU Doctoral Dissertations

The research aims are to enable the decision maker of an integrated vendor-buyer system under Consignment Stock (CS) policy to make the optimal/sub-optimal production/replenishment decisions when some general and realistic critical factors are considered. In the system, the vendor produces one product at a finite rate and ships the outputs by a number of equal-sized lots within a production cycle. Under a long-term CS agreement, the vendor maintains a certain inventory level at the buyer’s warehouse, and the buyer compensates the vendor only for the consumed products. The holding cost consists of a storage component and a financial component. Moreover, …


Silver Nanoparticles As Drug Delivery Systems, Ammar Tahseen Qureshi Jan 2013

Silver Nanoparticles As Drug Delivery Systems, Ammar Tahseen Qureshi

LSU Doctoral Dissertations

The goal of this project is to study the potential applications of silver nanoparticles (SNPs) in the medical device and pharmaceutical industries. Bone cements have been used in the orthopedic surgeries for many years to anchor prosthetics while filling up the spaces between the prostheses and bone. Antibiotics are an active component of bone cements but the increasing bacterial resistance to these antibiotics and difficulty of shaping and molding the bone cements increases the need for new antimicrobial biomaterials. Adult stem cell based regenerative therapies have been one of the most widely researched areas of tissue engineering. This is due …


Microstructure And Physics-Based Structural Models For Suspended Clay-Exopolymer Flocs, Xiaoling Tan Jan 2013

Microstructure And Physics-Based Structural Models For Suspended Clay-Exopolymer Flocs, Xiaoling Tan

LSU Doctoral Dissertations

Costal or shoreline waters are often characterized by high concentrations of suspended cohesive sediments (or clay) affected by varied organic matters (mostly extracellular polymeric substances or exopolymers), salt, and hydrodynamic disturbance. Resulting from the flocculation-disaggregation between the colloidal clay and exopolymer, the size and structure changes of the cohesive sediments are of key importance for understanding sediment transport processes (i.e., settling, breakage, and survivability) and the geotechnical and geophysical properties of the bottom bed. Because the coastal environment is extremely complicated, with many unpredictable and uncontrollable parameters, current knowledge is still insufficient to predict or fully explain the behavior of …


Geodatabase-Assisted Storm Surge Modeling, Sait Ahmet Binselam Jan 2013

Geodatabase-Assisted Storm Surge Modeling, Sait Ahmet Binselam

LSU Doctoral Dissertations

Tropical cyclone-generated storm surge frequently causes catastrophic damage in communities along the Gulf of Mexico. The prediction of landfalling or hypothetical storm surge magnitudes in U.S. Gulf Coast regions remains problematic, in part, because of the dearth of historic event parameter data, including accurate records of storm surge magnitude (elevation) at locations along the coast from hurricanes. While detailed historical records exist that describe hurricane tracks, these data have rarely been correlated with the resulting storm surge, limiting our ability to make statistical inferences, which are needed to fully understand the vulnerability of the U.S. Gulf Coast to hurricane-induced storm …


Automated Semantic Content Extraction From Images, Mahdi Arab Khazaeli Jan 2013

Automated Semantic Content Extraction From Images, Mahdi Arab Khazaeli

LSU Doctoral Dissertations

In this study, an automatic semantic segmentation and object recognition methodology is implemented which bridges the semantic gap between low level features of image content and high level conceptual meaning. Semantically understanding an image is essential in modeling autonomous robots, targeting customers in marketing or reverse engineering of building information modeling in the construction industry. To achieve an understanding of a room from a single image we proposed a new object recognition framework which has four major components: segmentation, scene detection, conceptual cueing and object recognition. The new segmentation methodology developed in this research extends Felzenswalb's cost function to include …


Resolving Pronominal Anaphora Using Commonsense Knowledge, Seyedeh Leili Javadpour Jan 2013

Resolving Pronominal Anaphora Using Commonsense Knowledge, Seyedeh Leili Javadpour

LSU Doctoral Dissertations

Coreference resolution is the task of resolving all expressions in a text that refer to the same entity. Such expressions are often used in writing and speech as shortcuts to avoid repetition. The most frequent form of coreference is the anaphor. To resolve anaphora not only grammatical and syntactical strategies are required, but also semantic approaches should be taken into consideration. This dissertation presents a framework for automatically resolving pronominal anaphora by integrating recent findings from the field of linguistics with new semantic features. Commonsense knowledge is the routine knowledge people have of the everyday world. Because such knowledge is …


Optimizing Light Requirements And Dilution Rates For Maximizing Algal Cell Growth And Lipid Content For Biofuel Feedstock Production, Beatrice Gabriela Terigar Jan 2013

Optimizing Light Requirements And Dilution Rates For Maximizing Algal Cell Growth And Lipid Content For Biofuel Feedstock Production, Beatrice Gabriela Terigar

LSU Doctoral Dissertations

There is a rapidly growing interest in the potential of microalgae as feedstock for the next generation of biofuels. The current study was designed to meet the following objectives: (1) Investigate the interdependence among cell density, biomass and lipid productivity to maximize feedstock production from outdoor cultures; (2) Investigate the effect of cycling high-intensity lights to identify optimum Dark:Light (D/L) ratios, which can be effectively used by researchers to maximize aerial biomass productivities; (3) Develop a deterministic model to simulate the biomass productivity in an continuous-flow bioreactor at various hydraulic retention times. Results indicated that variation in HRTs has a …


The Investigation Of Valve Operators' Torque Production Capabilities And Optimal Handwheel Height, Angle, And Opening Technique, Saif K. Al-Qaisi Jan 2013

The Investigation Of Valve Operators' Torque Production Capabilities And Optimal Handwheel Height, Angle, And Opening Technique, Saif K. Al-Qaisi

LSU Doctoral Dissertations

This research consists of two projects concerned with handwheel-valve operations. The objectives of poject-1 were to: (1) introduce an ergonomically-modified valve-wrench and compare it to conventional valve-opening methods, in terms of efficiency (time to open valve), perceived physical exertion (Borg-scale), and muscle loading of shoulder and trunk muscles; and (2) determine whether the torque setting (15 Nm and 30 Nm) of the valve affects the preferred valve-opening method. Four methods were evaluated, including using bare hands (BH), conventional wrench-restricted (CW-R, assumes presence of obstructions), conventional wrench-unrestricted (CW-U, assumes no obstructions), and modified wrench (MW). Electromyography (EMG) activities were measured from …


Development Of Cost-Effective And Benign Lipid Extraction System For Microalgae, Javed Iqbal Jan 2012

Development Of Cost-Effective And Benign Lipid Extraction System For Microalgae, Javed Iqbal

LSU Doctoral Dissertations

A laboratory-made continuous flow lipid extraction system (CFLES) was devised to extract lipids from microalgae Nannochloropsis sp., a potential feedstock for biodiesel fuel, with a focus to assess the workable temperatures and pressures for possible scale-up applications. Using conventional solvents, the CFLES recovered 100% of the lipids recovered with conventional Soxhlet extraction (USEPA method 3540) at moderate 50 psi pressure and 100°C temperature; conditions significantly lower than those normally used in pressurized liquid extractions requiring specialized equipment. Approximately 87% of the extracted oil was successfully transesterified into biodiesel fuel. For exploring the solvent potential of biodiesel, CFLES was also tested …