This dissertation studies an operational policy for a lean supply chain system consisting of a manufacturer, multiple suppliers and multiple buyers. The manufacturer procures raw materials from the suppliers and converts them into finished products, which are then shipped in batches to the buyers at certain intervals of times. Three distinct but inseparable problems are addressed: single supplier and single buyer with fixed delivery size (FD), multiple suppliers and multiple buyers with individual delivery schedule (MD), and time dependent delivery quantity with trend demand (TD). The mathematical formulations of these supply systems are categorized as mixed-integer, nonlinear programming problems (MINLAP) with discrete, non-convex objective functions and constraints. The operations policy determines the number of orders of raw material, beginning and ending times of cycles, production batch size, production start time, and beginning and ending inventories. The goal is to minimize the cost of the two-stage, just-in-time inventory system that integrates raw materials ordering and finished goods production system. The policy is designed for a finite planning horizon with various phases of life cycle demands such as inception (increasing), maturity (level) and phasing out (declining). Analytical results that characterize the exact, optimal policy for the problems described above are devised to develop efficient and optimal computational procedures. A closed-form heuristic that provides a near-optimal solution and tight lower bound is proposed for the problem FD. A network model to represent the problems is proposed and network-based algorithms are implemented to solve the problems FD, MD and TD optimally. The computational complexities of the algorithms are Θ(N²) or O(N³) where N is the total number of shipments in the planning horizon. Numerical tests to assess the robustness and quality of the methods show that the present research provides superior results. Production and supply chain management play an important role in ensuring that the necessary amounts of materials and parts arrive at the appropriate time and place. A manager, using the models obtained in this research, can quickly respond to consumers' demand by effectively determining the right policies to order raw materials, to deliver finished goods, and to efficiently manage their production schedule.

Self-compacting concrete, also referred to as self-consolidating concrete, is able to flow and consolidate under its own weight and is deaerated almost completely while flowing in the formwork. It is cohesive enough to fill the spaces of almost any size and shape without segregation or bleeding. This makes SCC particularly useful wherever placing is difficult, such as in heavily-reinforced concrete members or in complicated workforms. The objectives of this research were to compare the Splitting Tensile Strength and Compressive Strength values of self-compacting and normal concrete specimens and to examine the bonding between the coarse aggregate and the cement paste using the Scanning Electron Microscope. Cylinder specimens (8" by 4") were tested for Splitting Tensile and Compressive Strength after 28 days of standard curing, in order find out if self-compacting concrete would show an increase in these strengths and a better bonding between aggregate and cement paste, compared to normal concrete. The mix design used for making the concrete specimens was based on previous research work from literature. The water - cement ratios varied from 0.3 to 0.6 while the rest of the components were kept the same, except the chemical admixtures, which were adjusted for obtaining the self-compactability of the concrete. All SCC mixtures exhibited greater values in both splitting tensile and compressive strength after being tested, compared to normal concrete. The splitting tensile strength increased by approximately 30%, whilst the compressive strength was around 60% greater. In addition, the SCC tensile strengths after 7 days were almost as high as those obtained after 28 days for normal concrete. This was possible due to the use of mineral and chemical admixtures, which usually improve the bonding between aggregate and cement paste, thus increasing the strength of concrete. Images taken from concrete samples having water-cement ratios of 0.3, 0.4, and 0.6, using the Scanning Electron Microscope, have shown that the widths of the physical interface microcracks were greater for normal concrete than for self-compacting concrete, which implies that the aggregate-cement bonds were better for SCC than for normal concrete.

The vast differences in strength, ultimate strain and modulus during high strain rate (HSR) deformation of materials have been a very long-standing subject of engineering interest. This thesis deals with characterization of mechanical properties of two composite materials, balanced angle-ply graphite epoxy laminates (fibrous composite) and syntactic foams (particulate composite). The focus of this study is to compare the mechanical properties of these composite materials at high strain rates and quasi-static conditions and to find out the effects of failure modes on HSR mechanical properties of these materials. Split Hopkinson Pressure Bar (SHPB) apparatus is used for the HSR testing of balanced angle-ply IM7/8551-7 graphite/epoxy laminates and syntactic foams at varying strain rates, ranging from 500 s^-1 to 1700 s^-1. Graphite/epoxy laminates with seven different fiber orientations including longitudinal and transverse are used in this study. Syntactic foams of four different densities are used in order to observe the density effect on the HSR properties. The aspect ratio (L/D) of all the specimens is kept equal to one. Failed specimens are consequently observed under optical and scanning electron microscope in order to understand the fracture modes of these materials. The results of the tests on both materials demonstrate considerable increase in peak strength and the elastic modulus under HSR. It is also observed that the failure strain values vary considerably with increasing strain rate. Fiber orientation, in case of balanced angle-ply graphite epoxy laminates and density in case of syntactic foams are found to influence the HSR mechanical properties and strain rate sensitivity of peak stress. Delamination caused by edge effects is the prominent mechanism of failure for graphite/epoxy specimens whereas vertical cracking through cenospheres is recognized to be the dominant mode of failure for syntactic foam specimens under HSR testing conditions. These results are essential for conducting realistic numerical simulations for safe design of structures.

The four-parameter kappa distribution (Hosking 1994) was analyzed with respect to the various possible shapes of the probability density function. The general form for the cumulative distribution function when both h and k are non-zero is: F(x) = { 1 - h [ 1 - k ( x - ξ ) / α ]^1/k }^1/h. The parameters h and k work together to define the function's shape, ξ affects location, and α is the scale parameter. A method of selecting parameters to minimize the Kolmogorov-Smirnov test statistic, D, was developed. The technique was first described for the logistic distribution, which is the special case of the kappa distribution with k = 0 and h = -1. Then the more general case, k = 0 and h ≠ 0, was further explored as a possibility for expanding the optimization technique. The optimization method was shown to provide the parameters h, ξ, and α such that the Kolmogorov-Smirnov test statistic, D, was minimized. This optimization was applied to several example data sets and found to produce distributions that fit the empirical data much better than the normal or lognormal distribution functions. The results have potential applications in describing the distributions of many types of real data, including, but not limited to, weather, hydrologic and other environmental data. Matching empirical data to an invertible probability distribution makes it convenient to simulate random data that follow closely the characteristics of the natural data. Preliminary inquiry suggested that the technique might be expanded to allow non-zero values of k. This would improve the shape flexibility slightly and produce slightly better fits to empirical data.

Studies of incineration of surrogates for hazardous wastes are conducted in the pilot-scale rotary kiln incinerator (RKI) at Louisiana State University (LSU) in Baton Rouge, Louisiana. The purpose of the research is to investigate methods of treating and destroying hazardous wastes in a cost-effective and environmentally sound way. The objective is to provide process data that will contribute to increased knowledge for RKI design and operation. The LSU facility is a College of Engineering Combustion Laboratory that is unique in its large size as a university laboratory. It is equipped with individual instruments for analysis of O₂, CO, CO₂, HCl, SOx and NOx and a mass spectrometer to continuously monitor products of combustion for rigorous evaluation of efficiencies of operation. Experiments conducted to investigate parameters and variables affecting the design and operation of the kiln substantiate mathematical treatment of material and energy balances. These investigations add new and useful data to be used in design of rotary kilns, a major objective of this research. One of the principal contributions of this dissertation relates to the effects of batch feeding on instability of the combustion process. Surges in temperature, pressure, and their effects on products of incomplete combustion are discussed. Other activities of the combustion laboratory are described: Incineration of still bottoms to recover byproduct potash produced by the Audubon Sugar Institute; burning of synthetic fireplace logs; study of incinerator stack gases; and determination of rates of fugitive emissions from flanges and valves. Economics of operation and maintenance of the facility are calculated, tabulated, and related to contract charges for combustion studies on behalf of industrial clients. Future prospects for the laboratory as a research and teaching facility are discussed.

This research focuses on the use of historical freeway traffic data for comparison of the precursory traffic conditions to that accident occurrence by using 15-minute traffic speed contour maps. The second order statistics measures, namely angular second moment (ASM), contrast and entropy were used as the traffic performance measures in order to compare the two situations. The data used is from I-4 freeway traffic condition database, stored in a SQL server and 1999 year accident database for the same I-4 freeway. The study section is located in Orlando, Florida. The approach shows an approach to understand the performance of the freeways in an efficient and easy way.

Louisiana Gulf Coast oysters (Crassostrea virginica) were subjected to thermal shucking treatments to effect adductor muscle release from both left and right valves. The oysters were instrumented with thermocouples to monitor and record process temperatures in the oysters and on the shell. Following treatment, the oysters were evaluated for relaxation and release of the adductor muscle, meat quality and texture, and for the effect of the treatments on the storage life of the oysters as measured by total microbial plate counts. The treatments of many oysters resulted in a complete release of the adductor muscle from the shell while maintaining a quality raw product. One of the most promising treatments was a 60 second steam injection followed by a 60 second hold time and 120 seconds of ice water bath. This treatment proved exceptional overall with shelf stability over 14 days, an overall Average Release Value of 1.18 and an overall Quality of 1.86, both of which are good. A second treatment consisting of a 15 second pre-heat followed by a 45 second steam injection, no hold time and 4 minutes of ice water bath resulted in an overall Average Release Value of 0.33, which is excellent, and an overall Quality of 2.10 which is very close to acceptable. Sixty-seven percent of the oysters subjected to this treatment were considered successfully shucked based on degree of release and quality. Processing did affect the texture of the oysters but seemed to have little overall effect on storage life. This low-pressure steam process shows promise as an effective, low-cost alternative to current, high pressure commercial oyster shucking processes.

This dissertation reports a research effort to microfabricate an electromagnetic relay for power applications using a multilayer UV-LIGA process. A mechanically wrapped coil was used and very simple design for the magnetic circuit was adopted to increase the design flexibility and performances. The broad material selection and the capability of making high aspect ratio microstructures of the UV-LIGA make the technology best suited for fabricating microelectromechanical power relays. Fabrication of the device required significant advances in the optical lithography of SU-8 negative photoresist. Research proved that aspect-ratios up to 40:1 in isolated open field structures of thickness between 1 and 1.5 mm can be obtained a standard broadband UV source. The principal factor in this achievement is the reduction of internal stress during the post-exposure bake process that eliminates large plastic deformations present during standard bake procedures. Another challenging issue associated with producing high aspect ratio microstructures is the development narrow groves and deep holes in SU-8 lithography. To overcome this obstacle, megasonic agitation was applied to the developer bath, which resulted in faster development rates, more uniform development, and the ability to produce structures with higher aspect ratios. To date, this process has been used to achieve 100:1 aspect ratio open field features and 45:1 intact cylinder arrays. A multi-layer SU-8 optical lithography and metal electrodeposition process was developed to fabricate the relay. The design required implementation of high aspect ratio lithographic processing techniques to produce a tall nickel magnetic core and insulated magnetic cup in which a pre-wrapped solenoid would be placed for electromagnetic driving. After insertion of the solenoid a Ni-Fe actuator was bonded to the relay base to complete the device. To better understand the fatigue life of electroplated microstructures, a theoretical model was developed determine the possible fracture mechanics properties and fatigue life of LIGA fabricated nickel and nickel-iron alloys for use in microsystems applications. The prototype micro-relays were tested for the dynamic characteristics and power capacity. The experimental results have confirmed that reasonably large current capacity and fast response speed can be achieved using electromagnetic actuation and the multi-layer UV-LIGA fabrication process developed.

Construction industry accounts for the largest number of occupational injuries and fatalities every year. Occupational Safety and Health Administration (OSHA) is an organization responsible for regulating and enforcing standards for various occupations to ensure safe working conditions including construction industry. As an OSHA requirement, every construction employer should employ a safety program that involves both training of the employees and frequent site inspections. OSHA has provided an online construction eTool as a training tool which also aids in the development of safety inspection procedures. Traditionally, safety inspections are paper based and usually designed to address a specific work area or procedure. The inspection reports did not include any detailed visual data which may increase the cost of maintenance and data mining for problem areas. This project explains the possibility of using Tablet PCs as tool for performing safety inspections at a construction site to identify occupational hazards. As a part of the project, a Tablet PC application, Hazard Prevention Tool (HPT), is developed that concentrates on the four prime hazard areas, Electrical, Falls, Struck By, and Trenching and Excavation, hazards. The application makes it possible to capture the image of the worksite and marking the problem areas on the image. After each site inspection, a report is generated which includes the worksite image with problem areas marked and possible solutions for each problem area based on the OSHA recommendations. A usability test is also conducted as a part of the project using three sample work sites.

Diamondlike carbon (DLC) films have been explored extensively in the past due to their highly attractive properties. However, the high level of internal stress developed during growth prevents deposition of thick films. Synthesis of DLC/DLC multilayers (DDM) presents a venue to overcome this drawback. In the present study, DLC films and DDM were deposited on Si substrate using dc plasma of CH₄ and Ar gas mixture. FTIR was used to analyze the structure of the DLC films. Mechanical properties of the films were characterized by microhardness testing and nanoindentation. The tribological properties were studied by conducting pin-on-disc experiments in the laboratory environment (relative humidity 40-60%). Optical profilometry was used to analyze Intrinsic stress in the films and the wear profiles. A preliminary study was conducted utilizing different processing parameter (bias voltage, chamber pressure and ratio of Ar to CH₄) to select the constituents of the DDM. Subsequently, DDM were synthesized consisting of alternating nanolayers of soft (high sp²content) and hard (low sp² content) DLC by varying: (i) individual layer thickness while keeping the thickness ratio of soft/ hard DLC film, λ = 1 and; (ii) λ. The multilayered films found to exhibit low intrinsic stress ranging mostly below the average values of the two individual components. Nanoindentation behavior of DDM was comparable to the parent films and no significant variation was observed in different DDM films. DDM films with λ=1 exhibited better tribological properties compared to the films with λ other than unity. The 50 nm/50 nm DDM film exhibited the best tribological properties. It combined the low friction coefficient of the soft DLC component and low wear rate of the harder DLC component. The stress was found to be the average of the parent DLC films; hence it possesses the promise to be deposited as a thick coating, while maintaining desirable mechanical and tribological properties.