High-power diode lasers (HPDL) are being increasingly used in industrial applications. Deposition of nickel from nickel carbonyl (Ni(CO)4) precursor by laser-induced chemical vapor deposition (CVD) was studied with emphasis on achieving high deposition rates. An HPDL system was used to provide a novel energy source facilitating a simple and compact design of the energy delivery system. Nickel deposits on complex, 3-dimensional polyurethane foam substrates were prepared and characterized. The resulting “nickel foam” represents a novel material of high porosity (>95% by volume) finding uses, among others, in the production of rechargeable battery and fuel cell electrodes and as a specialty high-temperature filtration medium. Deposition rates up to ~19 µm/min were achieved by optimizing the gas precursor flow pattern and energy delivery to the substrate surface using a 480W diode laser. Factors affecting the transition from purely heterogeneous decomposition to a combined hetero- and homogeneous decomposition of nickel carbonyl were studied. High quality, uniform 3-D deposits produced at a rate more than ten times higher than in commercial processes were obtained by careful balance of mass transport (gas flow) and energy delivery (laser power). Cross-flow of the gases through the porous substrate was found to be essential in facilitating mass transport and for obtaining uniform deposits at high rates. When controlling the process in a transient regime (near the onset of homogenous decomposition), unique morphology features formed as part of the deposits, including textured surface with pyramid-shape crystallites, spherical and non-spherical particles and filaments. Operating the laser in a pulsed mode produced smooth, nano-crystalline deposits with sub-100 nm grains. The effect of H2S, a commonly used additive in nickel carbonyl CVD, was studied using both polyurethane and nickel foam substrates. H2S was shown to improve the substrate coverage and deposit uniformity in tests with polyurethane substrate, however, it was found to have no effect in improving the overall deposition rate compared to H2S-free deposition process. Deposition on other selected substrates, such as ultra-fine polymer foam, carbon nanofoam and multi-wall carbon nanotubes, was demonstrated. The HPDL system shows good promise for large-scale industrial application as the cost of HPDL energy continues to decrease.

Liquefied Natural Gas (LNG) hazards include LNG flammable vapor dispersion and LNG pool fire thermal radiation. A large LNG pool fire emits high thermal radiation thus preventing fire fighters from approaching and extinguishing the fire. One of the strategies used in the LNG industry and recommended by federal regulation National Fire Protection Association (NFPA) 59A is to use expansion foam to suppress LNG vapors and to control LNG fire by reducing the fire size. In its application, expansion foam effectiveness heavily depends on application rate, generator location, and LNG containment pit design. Complicated phenomena involved and previous studies have not completely filled the gaps increases the needs for LNG field experiments involving expansion foam. In addition, alternative LNG vapor dispersion and pool fire suppression methodology, Foamglas® pool fire suppression (PFS), is investigated as well. This dissertation details the research and experiment development. Results regarding important phenomena are presented and discussed. Foamglas® PFS effectiveness is described. Recommendations for advancing current guidelines in LNG vapor dispersion and pool fire suppression methods are developed. The gaps are presented as the future work and recommendation on how to do the experiment better in the future. This will benefit LNG industries to enhance its safety system and to make LNG facilities safer.

Liquefied Natural Gas (LNG) is flammable when it forms a 5 – 15 percent volumetric concentration mixture with air at atmospheric conditions. When the LNG vapor comes in contact with an ignition source, it may result in fire and/or explosion. Because of flammable characteristics and dense gas behaviors, expansion foam has been recommended as one of the safety provisions for mitigating accidental LNG releases. However, the effectiveness of foam in achieving this objective has not been sufficiently reported in outdoor field tests. Thus, this research focused on experimental determination of the effect of expansion foam application on LNG vapor dispersion and pool fire. Specifically, for evaluating the use of foam to control the vapor hazard from spilled LNG, this study aimed to obtain key parameters, such as the temperature changes of methane and foam and the extent reduction of vapor concentration. This study also focused on identifying the effectiveness of foam and thermal exclusion zone by investigating temperature changes of foam and fire, profiles of radiant heat flux, and fire height changes by foam. Additionally, a schematic model of LNG-foam system for theoretical modeling and better understanding of underlying mechanism of foam was developed. Results showed that expansion foam was effective in increasing the buoyancy of LNG vapor by raising the temperature of the vapor permeated through the foam layer and ultimately decreasing the methane concentrations in the downwind direction. It was also found that expansion foam has positive effects on reducing fire height and radiant heat fluxes by decreasing fire heat feedback to the LNG pool, thus resulting in reduction in the safe separation distance. Through the extensive data analysis, several key parameters, such as minimum effective foam depth and mass evaporation rate of LNG with foam, were identified. However, caution must be taken to ensure that foam application can result in initial adverse effects on vapor and fire control. Finally, based on these findings, several recommendations were made for improving foam delivery methods which can be used for controlling the hazard of spilled LNG.

Foam separation is a simple and economic method for separation of surface-active molecules such as proteins and enzymes from aqueous solutions. In this study, lactic acid broth, spent brewer&rsquo / s yeast extract and residual beer was used to investigate the applicability and efficiency of foam separation technique in partial purification of fermentation products and recovery of valuable components from industrial waste streams. The effects of the process variables initial feed concentration, air flow rate, foaming time, liquid pool height and temperature on separation performance were studied and optimum conditions for removal of proteins from lactic acid broth was determined. Highest enrichment (172.2) and separation ratio (314) with a high protein recovery (45.2 %) were obtained by foaming 200 ml of lactic acid broth with an initial feed concentration of 0.018 mg/ml at an air flow rate of 38.5 cm3/min. Selectivity of foam separation in protein purification, and its effect on protein structure was investigated in brewery wastes using SDS-PAGE and native PAGE, respectively.

In the present study, production of titanium and Ti6Al4V alloy foams has been investigated using powder metallurgical space holder technique in which magnesium powder were utilized to generate porosities in the range 30 to 90 vol. %. Also, sintering of titanium and Ti-6Al-4V alloy powders in loose and compacted condition at various temperatures (850-1250oC) and compaction pressures (120-1125 MPa), respectively, were investigated to elucidate the structure and mechanical properties of the porous cell walls present due to partial sintering of powders in the specimens prepared by space holder technique. In addition, microstructure and mechanical response of the porous alloys were compared with the furnace cooled bulk samples of Ti-6Al-4V-ELI alloy subsequent to betatizing. It has been observed that the magnesium also acts as a deoxidizer during foaming experiments, and its content and removal temperature is critical in determining the sample collapse. Stress-strain curves of the foams exhibited a linear elastic region / a long plateau stage / and a densification stage. Whereas, curves of loose powder sintered samples were similar to that of bulk alloy. Shearing failure in foam samples occurred as series of deformation bands formed in the direction normal to the applied load and cell collapsing occured in discrete bands. Average neck size of samples sintered in loose or compacted condition were found to be different even when they had the same porosity, and the strength was observed to change linearly with the square of neck size ratio. The relation between mechanical properties of the foam and its relative density, which is calculated considering the micro porous cell wall, was observed to obey power law. The proportionality constant and the exponent reflect the structure and properties of cell walls and edges and macro pore character.

Porous TiNi alloys (Ti-50.4 at. %Ni and Ti-50.6 at. %Ni) with porosities in the range 21%-81% were prepared successfully applying a new powder metallurgy fabrication route in which magnesium was used as space holder resulting in either single austenite phase or a mixture of austenite and martensite phases dictated by the composition of the starting prealloyed powders but entirely free from secondary brittle intermetallics, oxides, nitrides and carbonitrides. Magnesium vapor do not only prevents secondary phase formation and contamination but also provides higher temperature sintering opportunity preventing liquid phase formation at the eutectic temperature, 1118 &deg / C resulting from Ni enrichment due to oxidation. By two step sintering processing (holding the sample at 1100 &deg / C for 30 minutes and subsequently sintering at temperatures higher than the eutectic temperature, 1118 &deg / C) magnesium may allow sintering probably up to the melting point of TiNi. The processed alloys exhibited interconnected (partially or completely depending on porosity content) open macro-pores spherical in shape and irregular micro-pores in the cell walls resulting from incomplete sintering. It has been found that porosity content of the foams have no influence on the phase transformation temperatures while deformation and oxidation are severely influential. Porous TiNi alloys displayed excellent superelasticity and shape memory behavior. Space holder technique seems to be a promising method for production of porous TiNi alloys. Desired porosity level, pore shape and accordingly mechanical properties were found to be easily adjustable.

Porous Ti-6Al-4V alloys are widely used in the biomedical applications for hard tissue implantation due to its biocompatibility and elastic modulus being close to that of bone. In this study, porous Ti-6Al-4V alloys were produced with a powder metallurgical process, space holder technique, where magnesium powders were utilized in order to generate porosities in the range of 50 to 70 vol. %. In the productions of Ti-6Al-4V foams, first, the spherical Ti-6Al-4V powders with an average size of 55 &mu / m were mixed with spherical magnesium powders sieved to an average size of 375 &mu / m, and then the mixtures were compacted with a hydraulic press under 500 MPa pressure by using a double-ended steel die and finaly, the green compacts were sintered at 1200

We present methods for incorporating bubbles into a photorealistc fluid simulation. Previous methods of fluid simulation in computer graphics do not include bubbles. Our system automatically creates bubbles, which are simulated on top of the fluid simulation. These bubbles are approximated by spheres and are rendered with the fluid to appear as one continuous surface. This enhances the overall realism of the appearance of a splashing fluid for computer graphics. Our methods leverage the particle level set representation of the fluid surface. We create bubbles from escaped marker particles from the outside to the inside. These marker particles might represent air that has been trapped within the fluid surface. Further, we detect when air is trapped in the fluid and create bubbles within this space. This gives the impression that the air pocket has become bubbles and is an inexpensive way to simulate the air trapped in air pockets. The results of the simulation are rendered with a raytracer that includes caustics. This allows the creation of photorealistic images. These images support our position that the simple addition of bubbles included in a fluid simulation creates results that are much more true to life.

Low-pressure, low-producing natural gas wells commonly encounter liquid loading during production. Because of the decline in the reservoir pressure and the flow capacity, wells can fall below terminal velocity. Identifying and predicting the onset of liquid loading allows the operators to plan and prepare for combating the liquid loading hence saving valuable reserves and downtime. The present industrial applications of artificial lift, wellhead pressure reduction by compressor installation at the wellheads and reduction in tubing size are costly and often intermittent. The thesis examines the above aspects to generate a workflow for identifying and predicting the liquid loading conclusively and also assessing the application of Auger Tool and foam combination towards achieving a cost effective and more efficient solution for liquid unloading. In chapters I-IV, I describe the process of using production surveillance software of Halliburton Digital Consulting Services, named DSS (Dynamic Surveillance Software), to create a workflow of identifying the liquid loaded wells based on well data on daily basis for field personnel and engineers. This workflow also decides the most cost effective solution to handle it. Moreover, it can perform decline analysis to predict the conditions of liquid loading. In chapters V-VIII of the thesis, I describe the effort of handling the problem of liquid loading in a cost effective manner by introduction of an inexpensive Auger Tool in the bottomhole assembly and using WhiteMax surfactant soapstick from J&J Solutions. Four different combinations of well completion and fluid were tested for performance in respect to liquid hold up, pressure loss in the tubing, unloading efficiency and critical flow requirement. The test facilities and instruments, along with the operational methods, are discussed in chapter VI. Except for the reduction of the operational envelope with the inclusion of Auger Tool, the performance improved with the insertion of Auger Tool. The best combination of Auger and foam system could be a result of flow modification by the Auger Tool caused by reduced pressure loss and increase in drag coefficient and also by reduced density and surface tension of foam.

Cellulose nanowhiskers reinforced poly(vinyl alcohol)(PVA) nanofiber web is successfully fabricated using electrospinning technique and the mechanical properties of the single electrospun fiber are measured using nanoindentation method. The morphology and mechanical properties of highly aligned electrospun fiber webs are investigated. It is found that the modulus and tensile strength of aligned webs are higher than those of isotropic electrospun fiber webs. Experimental results are compared with a longitudinal Halpin-Tsai model. Ice-templated(IT) cellulose microfibril porous foams are successfully fabricated via unidirectional freezing methods. The morphology and growth mechanism of IT surfaces are investigated successfully using cellulose microfibrils and hydrophillic substrates. By controlling the temperature gradient between cellulose microfibril suspensions and secondary freezing mediums, various surface structures including honey-comb like structures, ellipse-shape channel strcutures, fully developed multichannel structures are obtained. For the honey-comb like patterned surface, high contact angles are observed. On the other hand, for the layered patterned surface, anisotropic wetting properties are observed.