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Yes / Waxy crude oils are pumped hot but upon power cut, pumping stops, the oil cools leading below the wax appearance temperature to precipitation of the wax and the formation of a gel throughout the pipe. In such a situation, what is the minimum pressure required to restart flow, not to merely deform the gel or break it? This paper provides a solution to this problem using microscopic observations under controlled cooling conditions and rheological data conducted in constant stress mode under controlled temperature and cooling conditions and restart experiments in laboratory pipelines replicating the rheometric conditions and deviations from them to inform large diameter operation in the field. Three important findings derive from the experimental data collected: (i) A fragmentation stress , rather than the static stress that precedes it, is found to be the more accurate predictor of flow re-start pressures; (ii) Waxy crude oils gels exhibit true yield stress and yielding process but also show flow on application of the slightest stress below yielding; (iii) This flow, in the elastic region, is jagged rather than continuous suggesting a consolidation process of the crystals and their agglomerates forming the gel. In the broader context of the existence of a yield stress, the data presented here show that there is such a thing as a yield stress and the concepts of a yield stress and that everything flows are not mutually exclusive.

No / In this paper, hydrodesulfurization (HDS) of crude oil in the three-phase slurry reactor over cobalt – molybdenum catalyst (CoMo / ɣ- AL2O3) is studied. Effects of space velocity and length of reactor on the conversion rate and catalyst effectiveness for HDS process have been investigated. Kinetics of the reaction rate for this process is primarily and Arrhenius equation for the rate constant is used. The results show that the effectiveness factor for catalyst along the length of reactor is decreased about 83%. By increasing liquid velocity from 4 to 10 1/s, the conversion of sulfur components is decreased about 22% at the temperature of 523 K. At the same temperature, by increasing liquid velocity from 36 to 84 1/s conversion is reduced to 25%. The results of the variation of the dimensionless reaction rate against conversion show that with increasing conversion, the reaction rate decreases and the reaction is stopped when the conversion is 100%.

Currently accepted optimum protein levels for growth in the horse may be reduced with amino acid supplementation. This study investigated the effects on growth and protein status of Thoroughbred foals offered a supplement with a typical CP level to a supplement that had a lower CP level fortified with limiting amino acids. The control supplement (CS) contained 14% CP, 3.0 Mcal/kg DM, 10% corn oil, 22% soybean meal, 1.4% calcium, and three sources of fiber. The experimental supplement (LTS) contained 9% CP, 3.0 Mcal/kg DM, 10% corn oil, 3% soybean meal, 1.4% calcium, three sources of fiber, and was fortified with .6% lysine and .4% threonine. Lysine and threonine are the first two limiting amino acids in common diets of the horse. Mares and foals were fed twice daily (0700 and 1400) and kept on 30-acre pastures (mixed grass/white clover) until weaning (7 months). Weanlings continued on specified supplements and pastures for seven additional months. Physical measurements and blood samples were taken monthly. Measurements included weight, average daily gain (ADG), body condition (BC), wither height, hip height, length, girth, forearm length, front and hind cannon length, physis and fetlock circumference. Blood analysis included total protein (TP), albumin (ALB), creatinine (CREA), and plasma urea nitrogen (PUN). Effect of diet and time were evaluated by analysis of variance with repeated measures. No differences were found in physical measurements between the CS and LTS groups (ADG 0.8(0.4 kg/day, BC 4.9(0.05) for the observational period. Blood data also showed no difference for the period (ALB 2.9 ( 0.03 g/dl, TP 5.7 ( 0.10 g/dl, CREA 1.1 ( 0.02 mg/dl). These results suggest that the foals offered the LTS faired as well or better than foals on the CS. Lower levels of crude protein (CP) in the diet will result in less nitrogen pollution of pasture lands due to better utilization in the horse. By fortifying a low protein diet with the first two limiting amino acids, the protein is used more efficiently for growth and development, thereby benefiting both the horse and the land. / Master of Science

The objective of this thesis was to understand the factors that affect the selection of remedial treatments for the complex staining of masonry materials on cultural resources located in environmentally sensitive sites such as Fort Livingston, Louisiana, on the Gulf Coast of the United States and other locations impacted by pollutants including crude oil. After the Deepwater Horizon oil spill in April 2010, the brick-and-tabby Fort was stained by crude oil. The EPA recommends SWA for removal of oil from solid surfaces such as masonry; however, limited research has been conducted into SWA effective for removal of crude oil from masonry, particularly in remote and environmentally sensitive locations. Research was conducted collaboratively at NCPTT and UT-Austin to identify a series of suitable SWA and to develop methods for evaluating SWA effectiveness in the laboratory. Products were selected for laboratory evaluation that do not require long dwell times, are easy to transport to the site, can be applied with portable equipment, produce effluent that can be collected for off-site disposal, and are listed on the EPA-published NCP Product Schedule. Two sets of 36 brick samples each were soiled with crude oil from the Fort. One set of samples was artificially weathered and one set was unweathered prior to being cleaned with selected six SWA. Laboratory evaluation shows that the primary factor affecting cleaner selection for remediation of brick masonry stained by light crude oil is the extent of weathering of oil on the masonry. For light crude oil, such as that spilled in the Gulf, organic solvent-based cleaners may be most effective if cleaning is possible soon after the staining occurs. Aqueous surfactant cleaners are most effective for removing weathered light crude oil from masonry. The following SWA listed in order of performance are recommended for field trials at Fort Livingston: 1. Cytosol; 2. SC-1000; 3. De-Solv-It APC; 4. De-Solv-It Industrial followed by De-Solv-It APC; 5. De-Solv-It Industrial followed by SC-1000. / text