In this thesis, coal-water mixtures (CWM) with &Ccedil / ayirhan lignite were prepared to optimize the parameters of CWM having an ideal behavior which means that at maximum coal loading, relatively stable at static and dynamic conditions and exhibit low viscosity. For this purpose, the effect of the parameters such as pulp density, amount of chemical agents, particle size distribution, addition of methanol and pulp pH were investigated. Results showed that increasing pulp density negatively affects viscosity and allowable maximum pulp density was obtained as 60% when the particle size distribution has a d50 value of 22.82 &micro / m. The optimum amount of chemical agent was found as 0.9%, having 10% Na-CMC (Sodium Carboxymethyl Cellulose) and 90% PSS (Polystyrene Sulfonate). Minimum viscosity was achieved when the pulp pH was in natural conditions (pH=6.85). Addition of methyl alcohol increased the viscosity of CWM.

Self compacting concrete (SCC) is first developed in Japan in the late 1980s in order to overcome the consolidation problems associated with the presence of congested reinforcement. It is also termed as a high performance concrete, as it can flow under its own weight and completely fill the formworks. As the fresh properties of SCC are quite important, mix design of a SCC is performed by considering various workability related fresh properties. Therefore, a well designed SCC should satisfy all requirements of a hardened concrete, besides its superior workability properties. The aim of this research is to assess the effects of some basic ingredients of SCC on the fresh properties of SCC. This will be performed by applying design of experiment techniques and obtaining significant statistical models, which will give valuable information about the effects of the model parameters on the rheology and fresh state characteristics of SCC. In this research program, four different variables / use of fly ash replacement, use of high range water reducing admixture (HRWRA), use of viscosity modifying admixtures (VMA) and water-cementitious material ratio, are considered as the variables of the experimental design. Central Composite Design (CCD), a design of experiment technique, is employed throughout the experimental program and a total of 21 mixtures of concrete are cast. Slump flow, V-funnel, L-box, sieve segregation, initial and final setting time tests are performed, furthermore / to investigate the effects of these variables to the rheology of SCC, relative plastic viscosity and relative yield stress, which are the parameters of Bingham Model are measured with the help of a concrete rheometer. As a result of the experimental program, the fresh state properties of SCC are expressed by mathematical equations. Those equations are then used in order to explain the effects of fly ash replacement, HRWRA and VMA concentration, and the w/cm ratio on the fresh state properties of SCC. According to the derived models, it is stated that the water-cementitious material ratio of the concrete mixture is the most effective parameter on the flowability and passing ability of SCC beside the other parameters utilized in this research as its coefficient was the highest in the related models.

The main objective was to determine the variation of physical properties of different cake formulations during baking in microwave and infrared-microwave combination ovens. In the first part of the study, rheological and dielectric properties of cake batter with different formulations were determined. Different concentrations of fat and different types of emulsifier and fat replacer were used. The variation of formulation had a significant effect on the apparent viscosity of the cake batter. Cake batter was found to show shear thinning and time independent behaviour for all formulations. Dielectric properties of cake batter were dependent on formulation, frequency and temperature. In the second part of the study, physical properties (dielectric properties, volume, texture, color and porosity) of cakes baked in microwave and infrared-microwave combination oven were determined. In addition, starch gelatinization during baking was investigated. For comparison, cakes were also baked in conventional oven. Formulation and baking time were found to affect physical properties and gelatinization degree of cakes. Addition of fat to the formulation was found to increase the dielectric properties and gelatinization degree of microwave and infrared-microwave combination baked cakes. For both microwave and combination baking, cake samples with SimplesseTM had the highest volume but the firmest texture. Addition of maltodextrin resulted in a more uniform structure for infrared-microwave combination baking. There was insufficient gelatinization in microwave baked cakes ranging from 70 to 78% depending on fat content. The gelatinization degree ranged from 88 to 93% in conventionally baked cakes. Combining infrared with microwaves increased gelatinization degree (80-90%).

In drilling technologies, Na-bentonite-water mixtures are used as drilling mud. As the reserves of sodium-bentonite decline, calcium or low-quality bentonites are activated with inorganic salts and/or treated with different types of polymers as an alternative to Na-bentonite. The quality of such bentonites, commonly referred to as extended bentonite may deteriorate under severe drilling conditions, such as / bacterial activity, high temperature etc. It was considered that borates could prevent the deterioration of extended bentonites due to their well known bactericide properties. This study involves the use of Na-Borate as an activating agent for bentonites in place of the commonly used Na-carbonate. The effects of Na-borate on the rheological and filtrate behaviours of two different bentonites, namely, Edirne Bentonite (E-Ben) and &Ccedil / ankiri Bentonite (C-Ben) were investigated. The results were evaluated based on API standards and in comparison to those of Na-carbonate activated bentonites. It was found that Na-borate could be used as a bentonite activator, although somewhat higher dosages (3,78% Na2O equivalent for E-Ben and 0,76% Na2O equivalent for C-Ben) than Na-carbonate (2,90% Na2O equivalent for E-Ben and 0,58% Na2O equivalent for C-Ben) are necessary to obtain the same rheological properties. In terms of aging, it was determined that aging had no adverse effect on v the rheological and filtrate properties of bentonite treated with carboxymethyl cellulose (CMC) and polyanionic cellulose (PAC), but rheological properties of bentonites treated with xanthan gum were found to deteriorate upon aging. The presence of Na-borate in the mud appears to alleviate this adverse effect.

In this thesis, development process of de-icing and anti-icing solutions and their flow instability characteristics are presented. In the beginning, the chemical additives in the solutions and their effects on the most critical physical properties of the solutions were investigated. Firstly, chemical additives were added to glycol and water mixtures at different weight ratios one by one in order to see their individual effects. Then, the changes in physical properties were observed when the chemicals were added to water-glycol mixture together. After that, study was focused on effect of polymer which makes the solution pseudoplastic. Further investigations on viscosity behavior of the solution at different pH values, glycol and water mixtures and surfactant weight ratios, which is used for surface tension reduction, were performed. For the investigation of flow instability characteristics of the solutions&rsquo / flows, linear stability analysis for two-layer flows is a basic tool. Firstly, the effects of main parameters on the stability of two-layer flows were observed with a parametric study. Then, the commercially available and developed de-icing and anti-icing solutions were compared according to the characteristics of unstable waves. According to the results, unstable waves on developed de-icing fluids are observed at a lower critical wind speed compared to the commercially available de-icing solution. Moreover, it flows off the wing faster due to a higher value of critical wave speed. Developed anti-icing solution has similar wave characteristics compared to commercially available anti-icing solution, except critical wave speed, which is significantly lower. However, this problem can be overcome by decreasing the viscosity of developed anti-icing solution at very low shear rates.

The main objective of this study was to investigate the fibers and their effects and availability in ketchup (tomato fiber) and cake (wheat bran fiber) production. In order to this, rheological properties of ketchups with tomato fiber, and cake (100, 80, 60 g flour formulations) with wheat bran fiber in different concentrations were investigated. Tomato powder in ketchup and wheat bran in cake was used for comparison. The samples studied had pseudoplastic behavior having a definite yield stress with a good fit for the Herschel-Bulkley model. The viscosity and yield stress values increased as the percentage of fiber increased. Moreover the samples were found to be more elastic than viscous (G&rsquo / &gt / G&rsquo / &rsquo / ). Both G&rsquo / and G&rsquo / &rsquo / values increased with oscillatory frequency, percentage of fiber, and in cake samples decreased as the amount of flour decreased. Stability measurements of ketchups studied were done by using Lumisizer. The microstructure of tomato powder, wheat bran and fibers were investigated under SEM. It was seen that the fibers had branched, long and thin structure while the other two had lumy and thick structure. The pressure used, resulted in this structure with increased surface area and finally increased water holding capacity in fibers. Moreover, texture of cakes prepared was all investigated in terms of volume, outer surface, hardness, cohesiveness and gumminess. Finally it was found to be possible to produce healthier ketchups and cakes with fiber in a good quality by decreasing the other undesired ingredients.

Hydrogenation is one of the most applied techniques in the fats and oils industry to produce wide range of hardened fats with different physical and chemical properties. Each different combination of hydrogenation conditions serves products of different rheological and micro-structural properties. Therefore, the purpose of this study is to examine the effect of different industrially available catalysts on rheological and micro-structural properties of hydrogenated fats. Three different catalysts were used at two different concentrations to hydrogenate soybean oil. Two nickel based (Nysosel 222 and SP 10) and one palladium based (Pd/Al2O3) catalyst were employed. Each oil sample was hydrogenated for 20, 40, 60, 80 and 100 minutes of time intervals, under 165 &ordm / C temperature, 2 bar H2 pressure and 500 rpm stirring rate. Resulting hardened fat samples were analysed in terms of rheological and microstructural properties. The outcomes of rheological and micro-structural analyses had a strong resemblence with the fatty acid distributions, solid fat contents, slip melting points and iodine values of the samples. The most selective catalyst was SP10, with the products of the highest trans fatty acid concent and more solid-like / where the least selective one was Pd/A with lowest trans fatty acid content and least solid-like. Crystal number and properties, the behaviours of storage and loss moduli were in correlation with trans fatty acid content of the samples. Also the moduli had a considerable parallelity with solid fat contents.

Dietary fiber is a component in the structure of plants which is an important aspect of diet and nutrition. The demand of fiber has increased significantly, as consumers recognize its health benefits such as reduction of risk of colon cancer, cholesterol lowering affect, regulating blood glucose levels and low calorie intake. Therefore food manufacturers pay more attention to develop new products containing high fiber content. Of all the categories of food products, bakery products are the most common fiber-enriched products. In this research two different wheat bran fibers (coarse and fine fibers) that are produced by microfluidization method are utilized in one of the highly consumed bakery product &ldquo / cracker&rdquo / . In this thesis study coarse and fine wheat bran fibers were utilized in different amounts with replace to wheat bran (0,15, 25, 35, 45, 55, 65, 75 g). The effects of wheat bran fiber on crackers were determined by rheological measurements of dough samples and it was found that as the amount of wheat bran fiber increases / elasticity increases as well. Textural analysis were conducted for both dough and cracker samples and these analysis demonstrated that wheat bran fiber containing dough had higher hardness values than non/less containing ones. In addition to the above analysis, HPLC analyses were done for ferulic acid determination which is a significant nutritive compound in wheat bran. It was concluded that ferulic acid amount in fiber was much higher than wheat bran. This research demonstrated that more nutritive and much fiber containing crackers could be made by using wheat bran fiber instead of wheat bran.

Properly preparing the drilling fluid is an essential part of any successful drilling operation, especially in complex operations like deviated and horizontal drilling. Understanding the flow behavior of the polymers used in the drilling fluids under different conditions takes a key part in this preparation. In this study, shear rheology of some traditionally used water soluble polymers in drilling and completion fluids / namely PAC (polyanionic cellulose) and xanthan gum, were investigated experimentally. Instead of an oilfield standard Fann Model 35 Viscometer, an Ofite Model 900 Viscometer was used because of its capability to measure at ultra-low shear rates. Effects of the concentration of the polymer, time of shear applied, test temperature and effects of aging were examined. Rheological measurements were conducted between the shear rate ranges of 0.01 to 1000s-1 with concentrations changing from 0.25 to 1.5 grams of polymer per 350 milliliters of water (equivalent to 0.25 to 1.5 lb/bbl). Rheograms were constructed to identify the effect the polymers in question have on the flow characteristics of the drilling fluid. An appropriate constitutive model was used to define the flow behavior of the polymer in question mathematically. It was observed from the constructed rheograms that increase in polymer concentration results in consistent increase of apparent viscosity. Amount of time of shear does not affect the selected polymers if they are dynamically aged at least for two hours. Also as expected increasing temperature of the sample lowers the apparent viscosity considerably.

Polymers are added to asphalt binders primarily to stiffen the binder at higher temperatures and thus to protect the pavement against rutting at summertime temperatures early in the pavement's life. Also, it has been noted that polymers typically increase the ductility of a binder and that some polymer-asphalt combinations are especially effective. Furthermore, it is hypothesized that enhancing a binder's ductility, and maintaining this enhancement with binder oxidative aging, contributes to enhanced binder durability in pavements. However, polymer-asphalt interactions and how they might contribute to improved binder performance is not well understood. The goal of this work was to probe the relationship of polymer morphology on asphalt binder rheology and mixture durability. Experiments were conducted on asphalt mixtures and binders, and as a function of oxidative aging. PFC mixtures, which are an open mixture designed to allow enhanced water drainage, were of specific interest. These mixtures were tested for Cantabro Loss, an indicator of a mixture's likelihood of failure by raveling. Asphalt binders were tested using dynamic shear rheometry (DSR), which provided the DSR function, (G' /η'/G'), a measure of binder stiffness that includes both the elastic modulus and the flow viscosity), ductility (used to measure the elongation a binder could withstand before failure), gel permeation chromatography (GPC), used to estimate the relative amount of polymer) and fluorescence microscopy (used to image the polymer morphology in the asphalt binder). From these data, relationships were assessed between binder morphology and binder rheology and between binder rheology and mixture durability, all as a function of binder oxidative aging. Polymer morphology related to ductility enhancement. Polymer morphology related to a change in the DSR function, relative to the amount of polymer, as measured by the polymer GPC peak height. Cantabro loss correlated to the DSR function (R2=0.963). The overall conclusion is that polymer morphology, as indicated by fluorescence microscopy, relates to both the rheological properties of the binder and the Cantabro loss of the mixture. These relationships should yield a better understanding of polymer modification, increased mixture durability (decreased raveling) and improved rheological properties (DSR function and ductility).