Spent acid retention in the near-wellbore region causes reduction of relative permeability to gas and eventually curtailed gas production. In low-permeability gas carbonate reservoirs, capillary forces are the key parameters that affect the trapping of spent acid in the formation. Capillarity is a function of surface tension at the gas-liquid interface and contact angle of the fluids in the rock. To weaken capillary forces, surface tension should be low and contact angle should be large. This work provides a comprehensive study on the effect of various common acid additives on carbonate rock wettability, and surface tension and contact angle, as the main parameters that control capillarity. Surface tension and contact angle experiments were conducted using Drop Shape Analysis (DSA) instrument at high temperature and pressure. Core flood experiments were also conducted to study the overall impact of the acid additives on wettability by analyzing irreducible fluid saturation in the rocks before and after spent acid exposure. Spontaneous water imbibition was conducted in each case to check for permanent or long-term wettability change as a result of using these additives. Acid additives such as methanol and corrosion inhibitors reduced both surface tension and contact angle. Iron control agents had no impact on surface tension, however, they decreased contact angle at the lower concentration used. Formic and acetic acids did not affect the surface tension, but they had a reducing impact on the contact angle. According to the core flood experiment results, formic acid decreased irreducible fluid saturation whereas methanol increased irreducible fluid saturation. On the other hand, the fluorochemical surfactant tested changed the rock wettability into more gas wetting. Use of this chemical would help in recovering spent acid. The results of the spontaneous water imbibition tests showed that organic acids and iron control chemicals did not have a permanent impact on wettability of the rocks. However, the wettability change as a result of using fluorochemical surfactant would persist for a long time as this chemical forms a film on the rock surface.

Presented in this thesis is a study of the effects of nano-sized particles used as a catalytic additive in composite solid propellant. This study was done with titanium oxide (titania)-based particles, but much of the findings and theory are applicable to any metal oxide produced by a similar method. The process required for efficiently producing larger batches of nanoparticle additives was seen to have a significant impact on the effectiveness of the additive to modify the burning rate of composite propellant consisting of ammonium perchlorate (AP) and hydroxyl terminated polybutadiene (HTPB). Specifically, titania was seen to be both an effective and ineffective burning rate modifier depending on how the nanoparticle additive was dried and subsequently heat treated. Nanoadditives were produced by various synthesis methods and tested in composite propellant consisting of 80 percent AP. Processability and scale-up effects are examined in selecting ideal synthesis methods of nanoscale titanium oxide for use as a burning rate modifier in composite propellant. Sintering of spray-dried additive agglomerates during the heat-treating process was shown to make the agglomerates difficult to break up during mixing and hinder the dispersion of the additive in the propellant. A link between additive processing, agglomerate dispersion mechanics and ultimately catalytic effect on the burning rate of AP/HTPB propellants has been developed by the theories presented in this thesis. This thesis studies the interaction between additive dispersion and the dispersion of reactions created by using fine AP in multimodal propellants. A limit in dispersion with powder additives was seen to cause the titania catalyst to be less effective in propellants containing fine AP. A new method for incorporating metal oxide nanoadditives into composite propellant with very high dispersion by suspending the additive material in the propellant binder is introduced. This new method has produced increases in burning rate of 50 to 60 percent over baseline propellants. This thesis reviews these studies with a particular focus on the application and scale-up of these nanoparticle additives to implement these additives in actual motor propellants and assesses many of the current problems and difficulties that hinder the nanoadditives’ true potential in composite propellant.

Matrix acidizing is a well stimulation technique used to remove formation damage in the near wellbore region. But it comes with an associated set of challenges such as corrosion of the tubulars and iron precipitation in the formation. To counter these challenges, different chemicals, or additives, are added to the acid solution such as corrosion inhibitors and iron control agents. These additives may change the relative permeability of the spent acid, and formation wettability, and may either hinder or improve spent acid clean-up. Such effects of additives on the spent acid clean-up have not been documented. The aim of this research effort was to document the aforementioned change in the spent acid concentration (by using one additive at a time) before and after gas flowback. This was achieved by acidizing cores and creating wormholes halfway through them, then CT scanning them to observe the spent acid region. Later on, gas was flown through the core opposite to the direction of acid injection for 2 hours, and another CT scan was taken. The difference between the two CT scans was documented. Using a different additive each time, a series of such CT scans was obtained to develop an idea about whether the said additive was beneficial or detrimental to spent acid clean-up. It was found that the corrosion inhibitor FA-CI performed the best in terms of spent acid recovery after gas flowback for both Indiana Limestone and Texas Cream Chalk cores. Moreover, the corrosion inhibitor MI-CI was the worst for Indiana Limestone and the non-emulsifying agent M-NEA the worst for Texas Cream Chalk for spent acid recovery after gas flowback.

The prime function of lubricating additives are to strength or improve the effect of lubrication and the unti¡Vwear capability of lubricating base oil. This research use the self-development EHL tester to explore the effects of ellipticity parameter of ring , load, speed, concentration and particle of lubricating additives and slip ratio on the film thickness.. During pure rolling, the film thickness increases with increasing speed, but decreases with increasing load, and the effect of speed on the film thickness is more obvious than the effect of load. The film thickness of lubricating additives varies insiginificant when the concentration of lubricanting additives are 1% and 3%, but it increases evidently at 7%. The effect of concentration developes good function of lubricant just under the condition of high speed and low load. Smaller particle of MoS2 has better lubricant effect than that it bigger. The number of particle of MoS2 distributed over lubricant contact zone increase with increasing concentration . The film thickness is getting thick when the ellipticity parameter increases. The minimum film thickness and central film thickness will decrease when slip ratio increase. That means , slip ratio and film thickness have a inversive relationship. Furthermore, when slip ratio increases, the central film thickness will decrease rapidly, but the minimum film thickness will just have a gentle decrease. It still has lubricant effect under the roll-slip state when the particles are smaller. During pure slipping, the bigger the particles, the easier it piles up on the entering area, and it makes lubricating oil can not enter the contact area easily.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

M. Tech. Chemical Engineering / Cement based materials are of enormous technological importance and their satisfaction depends on being able to transport and mould them in the freshly mixed state. The problem of the degradation or concrete is of interests to modern society, not only in terms of money, but in terms of discomfort and safety. Global research show concrete consumption around the world to be second only to water. The situation clearly indicates the significance and the huge role concrete has in the construction industry and in the global economy. This work was to investigate the various methods of increasing the life span of concrete without compromising its properties. The techniques for improving the physical properties of concrete and the effect of bacterial biofilm were studied especially for sanitary floors of food processing industries. The aim of this study is to improve the physical, mechanical and microbial properties of concrete floors in food processing industries by extending the life span of concrete materials.

No description available.

Clinoptilolite is a zeolite and an aluminosilicate that can be fed to swine in order to reduce nutrients being excreted because of their molecular sieving properties, high cation exchange capacities, and a high affinity for the ammonium ion (NH4+). Preliminary research has been carried out on utilizing zeolite's unique characteristics for dietary supplementation for livestock, however much of this research is limited and is still in its infancy. / The results from this study show that the zeolite with a particle size distribution either >250 mum or mixed (50% particles greater and smaller than 250 mum) adsorbed the most NH4+. Macro mineral and heavy metal release was similar among all particle size distributions tested, but varied between sources of zeolite. Handling properties of zeolite were not affected by moisture content or particle size. The feed trial indicated that zeolite supplementation, combined with a low crude protein and energy diet and at an inclusion level of 4%, showed potential as a feed additive in swine diets for the purposes of nutrient reduction. Nevertheless, zeolite seemed to have a greater impact on energy ingestion, as compared to crude protein. Even at 6% zeolite inclusion in the feed, hog muscle, kidney and liver tissues showed no significant increase in heavy metal contents, as compared to those fed any zeolite.

The rapid growth of Canadian pork industry has been challenged by its negative impact on the environment. To find an economical and promising solution to the environmental problems, 4% zeolite (90%+ clinoptilolite) were supplemented to a regular (100% crude protein (CP) and energy) or low CP and energy (90% CP and 90% energy or 90% CP and 85% energy) grower pig diets. Twenty male and twenty-four female grower pigs were used in two feeding experiments respectively, followed by a metabolic test with three batches of animals repeated to determine the metabolic effects of zeolite supplementation. Pig performance (body weight gain, daily feed intake and feed conversion ratio), and metabolic parameters (manure mass, feed intake, protein and energy conversion, as well as dry feed and organic matter retention) were evaluated. Zeolite supplementation at 4% to a regular diet for grower pigs had a positive but not significant (P > 0.05) effect on all pig performance and metabolic parameters, compared to the regular diet without zeolite. Among 4 rations, pigs on a regular diet with 4% zeolite performed consistently best throughout the entire trail, with decreased average daily consumption and reduced amount of feces, increased feed and organic matter retention in the gastrointestinal tract, improved feed as well as protein and energy conversion, and enhanced body weight gain. Moreover, zeolite supplementation at 4%, with 90% CP and 90% energy in grower pig diets, improved feed and protein and energy conversion rate, and increased body weight gain, when compared to those of pigs fed a regular diet without zeolite. However, a diet of 90% of CP and 85% of energy with 4% zeolite significantly (P < 0.05) increased feed consumption and the amount of feces produced, and decreased feed and organic matter retention in the gastrointestinal tract, thus reducing feed conversion rate. Therefore, 4% zeolite supplementation to the regular or low CP and energy (90% C / Key words. Clinoptilolite, Pig, Pig Performance, Metabolic Parameter.