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1
Stanbridge, L. H. "Microbial associations developing on modified atmosphere packaged beef steaks." Thesis, University of Bath, 1994. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239972.
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Reynolds, Lindsey. "Sensory Evaluations of USDA Select Strip Loin Steaks Enhanced with Sodium and Potassium Phosphates and USDA Choice Strip Loin Steaks for Comparable Palatability Factors." TopSCHOLAR®, 2011. http://digitalcommons.wku.edu/theses/1051.
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The cyclic nature of the beef industry is dependent on the supply and demand transaction initiated by consumers’ acceptability of quality meat products. When purchasing beef at the grocery store, consumers are dependent on USDA grades and visual appraisal; consumers expect consistency in products. Upon this appraisal, quality is determined by the color, marbling content, and texture of a particular retail cut, as well as cooked characteristics of tenderness, flavor, and juiciness. Variability in meat tenderness is a major quality defect of beef (Morgan et al., 1991b; Smith et al., 1992). A common practice used by beef processors to extend the shelf life and improve tenderness of beef products is “enhancing”. Even though enhancing products is effective for water and color retention and improved tenderness, these additives can negatively impact flavor by giving a bitter, salty or metallic taste. This experiment was conducted to determine the effect of enhancement on the eating quality of USDA Select strip loin steaks. After a training session, six students in the agriculture department at Western Kentucky University were selected to serve on a sensory panel. The panel members evaluated tenderness, juiciness, flavor, off-flavor, overall acceptability, and saltiness. The USDA Select strip loin steaks were enhanced with a 12% solution of sodium and potassium phosphate and USDA Choice strip loin steaks were non-enhanced. Results indicated the enhanced product was inferior for all palatability measures (P<.05). Enhanced USDA Select strip loin steaks were rated as being lower for tenderness, juiciness, flavor, overall acceptability, and more salty. Also, the enhanced strip loin steaks received significantly higher evaluations for off-flavor (P<.01). These data suggested that a 12% solution of sodium and potassium phosphates administered to USDA Select strip loin steaks lowered consumer satisfaction.
3
Fevold, Michaella Ann. "Tenderness and Juiciness of Beef Steaks from Varying Hot Carcass Weights." Thesis, North Dakota State University, 2019. https://hdl.handle.net/10365/31563.
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The objective of this study was to determine how hot carcass weights affect temperature decline and pH decline of beef carcasses, as well as, tenderness, juiciness and color of beef steaks. Carcasses were selected based on hot carcass weight. Carcasses were separated into either light, medium or heavy weight groups and temperature and pH decline were measured for 24 hours. There were no differences in pH decline, fat thickness, KPH or marbling score, drip loss, cook loss or WBSF among hot carcass weight classes. Light and medium carcasses weight had smaller longissimus areas compared to heavy carcasses. Light weight carcasses had lower USDA final yield grades compared to heavy carcasses. Color data indicated steaks from heavy carcasses were redder than steaks from light carcasses. Hot carcass weight did not have an influence on overall meat quality attributes of steaks, however, hot carcass weight did have an effect on color.
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Bagley, Jason Lee. "Consumer and shear force evaluation of steaks from the M. Serratus ventralis." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4706.
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An in-home evaluation of steaks from the M. Serratus ventralis was conducted to
determine consumer acceptance. Steaks were also evaluated by Warner-Bratzler shear
force (WBS) evaluations. Steaks from the M. Serratus ventralis were either blade
tenderized, injected with a salt, phosphate, and papain solution, or served as a control.
Consumers (n = 136) were not given a specific method of cookery, but were asked to
document cooking method and degree of doneness, overall-like, tenderness desirability,
tenderness of cut, juiciness desirability, juiciness of cut, flavor desirability, and flavor
intensity. When cooked on the grill, in the oven, or in a skillet, injected steaks received
the highest (P < 0.05) ratings for tenderness. Furthermore, consumers rated injected and
blade tenderized steaks higher (P<0.05) for overall like when they were cooked on the
grill to a higher degree of doneness. Oven cooked steaks that were injected, rated higher
(P<0.05) than blade tenderized steaks for juiciness. When cooked on the grill, juiciness
ratings were also higher (P<0.05) for injected steaks compared to control steaks.
Moreover, injected steaks had significantly lower (P<0.05) WBS values when compared
to blade tenderized and control steaks. Overall, ratings for all steaks were adequate,
confirming the M. Serratus ventralis as a potential high quality steak for use in the retail
market.
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Jedlicka, Megan Elaine. "The effects of functional oils on sensory attributes of beef ribeye steaks." [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1473219.
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Sledge, Lillie Marie Kerth Christopher R. "Characterizing grass-fed ground beef and enhanced steaks using modified atmosphere packaging." Auburn, Ala, 2008. http://hdl.handle.net/10415/1411.
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Emamgholizadeh, Fariba. "Effects of marinades on the formation of heterocyclic amines in grilled beef steaks." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/913.
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John, Liza. "Comparison of Color and Thiobarbituric Acid (TBA) Values of Cooked Hamburger Patties and Top Sirloin Steaks after Storage of Fresh Beef Chubs and Raw Steaks in Modified Atmospheres of 80% Oxygen or 0.4% Carbon Monoxide." DigitalCommons@USU, 2004. https://digitalcommons.usu.edu/etd/5520.
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This study compared the effect of packaging method (0.4% carbon monoxide, 80% oxygen or vacuum), storage time (7, 14 and 21 days) and internal cooking temperature 49, 57, 66, 71 and 79°C) on color and thiobarbituric acid (TBA) values of top sirloin steaks and ground beef patties. Ground beef was obtained from 3 different sources (chuck, loin and trim). All samples were stored at 2°C for 7, 14 and 21 days.
All raw ground beef samples stored in 0.4% carbon monoxide remained bright red throughout the 21-day storage period. The phenomenon of premature browning (appearance of cooked color at lower than normal cooking temperatures) was observed in samples stored in high oxygen. TBA values were highest for the samples stored in 80% oxygen. Internal a* redness values were lowest for samples stored in 80% oxygen. Percent myogobin denaturation (PMD) increased with increase in internal cooking temperature and was highest for the ground beef samples stored in 80% oxygen.
The a* redness values were highest for raw steaks stored in 0.4% CO. Steaks stored in vacuum had a uniform purple color, but some browning was noticed on the surface of the samples by day 14. PMD and TBA values of cooked top sirloin steaks were highest for the samples stored in 80% oxygen
This study confirms that high oxygen packaging promotes rancidity in ground beef and top sirloin steaks. Packaging in 0.4% carbon monoxide helps maintain a bright cherry red color in ground beef and top sirloin steaks for up to 21 days.
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Matney, MaryAnn Joy. "The effect of postmortem aging and location on tenderness of steaks from beef Semitendinosus and Longissimus lumborum." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/34673.
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Master of ScienceDepartment of Animal Sciences and Industry
Terry A. Houser
The objective of this study was to determine the effect of extended postmortem aging (DOA), steak location (LOC), and dietary treatment (TRT) on cooked meat tenderness, sarcomere length, and myofibrillar protein degradation of steaks from the Semitendinosus (ST) and Longissimus lumborum (LL). Crossbred feedlot steers (n = 40; initial body weight 638 ± 29 kg) were fed 45 d with the following diets: a control diet, control diet with microalgae meal, microalgae meal and antioxidants fed at the beginning of feeding, and microalgae meal with antioxidants fed during the final 10 d of feeding. The ST and LL were removed from carcasses. The ST was fabricated into 10 steaks, which were paired with an adjacent steak and assigned 5 LOC; LOC 1 was the most proximal and LOC 5 was the most distal. Each LOC was randomly assigned an aging period of 7, 14, 28, 56 or 112 d. The 6 most posterior steaks of the LL were paired with an adjacent steak and assigned 3 locations; LOC 1 being the most anterior and LOC 3 the most posterior. Each LOC of the LL was randomly assigned an aging period of 7, 28, or 112 d. Shear force, sarcomere length, muscle fiber type and size, postmortem proteolysis, and calpain activity were measured across aging periods for each LOC. Improved Warner-Bratzler shear force (WBSF) values were detected throughout the 112 d aging period for both ST and LL steaks (quadratic; P < 0.01). The largest decrease in shear force occurred between d 7 and 28 for LL and ST steaks. Shear force decreased (P < 0.01) from LOC 1 to LOC 5 (proximal to distal) in ST steaks. Steak LOC 5 had the longest sarcomeres over LOC 1, 2, and 3 on d 7, 14, and 28 (P < 0.01) in the ST; LOC 4 and 5 also had a greater percentage of Type I fibers (P < 0.01). Muscle fiber size in ST steaks decreased (P = 0.01) from LOC 1 to LOC 5. As DOA increased, intact calpain-1 decreased (quadratic; P < 0.01), with intact calpain-1 completely disappearing by d 56 and d 28 in the ST and LL, respectively. Intact desmin and troponin-T decreased throughout the 112 d in ST and LL steaks (linear; P ≤ 0.03). Degraded desmin-38 kDa increased (P < 0.01) between d 14 and d 28; however, degraded desmin-38 kDa did not continue to degrade (P = 0.76) from d 56 to d 112 in ST steaks. Degraded desmin-35 kDa content, however, continued to increase through d 112 (P < 0.01). Muscle fiber size and type along with sarcomere length played a substantial role in tenderness differences in steak LOC, whereas calpain and proteolytic activity played a substantial role across DOA.
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Ortega, Villicana Maria Teresa. "Escherichia coli O157:H7 and Salmonella spp. risk assessments for the production and cooking of restructured beef steaks /." Search for this dissertation online, 2003. http://wwwlib.umi.com/cr/ksu/main.
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Wilfong, Alaena. "Determination of the effect of branding on consumer palatability traits of ground beef and beef strip loin steaks." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/32776.
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Master of ScienceDepartment of Animal Sciences and Industry
Travis O’Quinn
The objectives of these studies were to determine how consumer palatability ratings of beef strip loin steaks and ground beef are affected when products are identified with a brand, USDA grade, or product type. Strip loins were selected to represent five quality levels and six ground beef treatments were chosen, representing a variety of fat levels and product types. After aging steaks for 14 d and ground beef for 8 d, 2.5 cm steaks and 151.2 g patties were formed. Consumer panelists evaluated samples for tenderness, juiciness, flavor liking, and overall liking as well as texture liking for ground beef samples. Additionally, consumers rated each palatability trait as either acceptable or unacceptable and rated the sample as either unsatisfactory, everyday quality, better than everyday quality, or premium quality. Samples were fed in two rounds – blind and informed testing. In the first round of blind testing, consumers were served one sample from each treatment with treatments not disclosed. For the second round of informed testing, USDA grade, or product information was disclosed prior to sampling. Samples evaluated by consumers were paired for blind and informed testing. During blind testing, Certified Angus Beef (CAB) steaks rated similar (P > 0.05) to Choice for all palatability traits; however CAB rated greater (P < 0.05) than Choice for all traits for informed testing. Additionally, Angus Select and Select steaks were rated similar (P > 0.05) when tested blind, but Angus Select was rated greater (P < 0.05) than Select for flavor and overall liking when treatment was informed. Prime, CAB, and Angus Select had increased (P < 0.05) ratings for flavor and overall liking due to brand disclosure. However, Choice and Select samples did not receive any increase (P > 0.05) in ratings for palatability traits when brand was informed. Multiple traits were rated greater for Prime, CAB, and Angus Select products indicating these products received a "brand lift" (change in ratings due to brand knowledge) in palatability due to brand identification. However, when brand information was disclosed for Choice and Select steaks, consumers indicated no increase in palatability perception. Few differences were observed in blind testing for ground beef; however, during informed testing, 90/10 CAB ground sirloin rated greater (P < 0.05) than all other products for all palatability traits besides juiciness. Increased (P < 0.05) ratings were found for CAB products for multiple traits while the only non-branded product that received increased (P < 0.05) ratings was 90/10 ground beef during informed testing. There were few differences among ground beef products when tested blind, indicating that during blind testing, brand, fat percentage, and subprimal source have little effect on ground beef palatability. However, when product and brand were identified, multiple treatments received increased ratings for palatability traits indicating branding and product type knowledge influence the palatability of ground beef.
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Gardner, ToniRae. "Analysis of Beef Steaks of Varying USDA Quality Grades and Thicknesses Cooked on Low and High Grill Surface Temperatures." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/5694.
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The objective of this project was to analyze the thermodynamics (thermal conductivity and diffusivity as well as protein denaturation) and physical properties (percent expressible moisture, cooking loss, change in steak thickness, shear force, texture profile analysis and rheological behavior) of beef steaks of different USDA quality grades (Upper 2/3 Choice and Select), thicknesses (thick and thin), and grill surface temperatures (high and low) cooked to the same internal degree of doneness to determine if a specific set of cooking parameters would create a profound difference in the eating characteristics, described by the tenderness and juiciness of cooked beef strip steaks.
The elastic behavior of the surface and centers of beef steaks were analyzed to determine how the microstructure of the beef responded to applied stress. The elastic behavior of steak centers was influenced in a three-way interaction between USDA Quality Grade, steak thickness, and grill surface temperature while the elastic behavior of the surface of steaks was influenced only by USDA Quality Grade and steak thickness. These interactions along with the differences in the thermal characteristic of proteins suggest that the microstructure of beef steaks is significantly affected by each cooking treatment group. The physical properties in the beef steaks further support through more tangible applications that the composition, thickness, and cooking regiments impact the microstructure and thermal properties of beef and thus final tenderness and texture.
This project identified cooking preparation should take into consideration that quality grade, thickness and cooking temperature will affect the textural eating qualities of beef steaks. Choice steaks were shown to be ideally sliced thick and cooked on a low grill surface temperature supported by the springiness, hardness, expressible moisture, and rheological data. Select steaks were not always effected by grill surface temperature and had similar results among the different measurements but the hardness, resilience and chewiness values along with viscosity suggest a thick steak cooked at a high grill surface temperature. Therefore, cooking parameters may be utilized as a mechanism to enhance beef steak palatability.
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Gunderson, Jennifer Ann. "Effects of Zilpaterol hydrochloride feeding duration on color of beef and Holstein semimembranosus steaks packaged in PVC and MAP systems." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/1704.
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Gardner, Kourtney. "Comparison of Beef Flavor Compounds from Steaks and Ground Patties of Three USDA Quality Grades and Varied Degrees of Doneness." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/6508.
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This study determined how quality grade and degree of doneness influence the development of beef flavor compounds among whole muscle and ground patties. Proximate composition, pH, cooking duration, neutral and polar lipid fatty acids, free and total amino acids, total reducing sugars, and volatile compounds were evaluated in beef strip steaks and ground patties of Longissimus lumborum from three USDA quality grades (Prime, Low Choice, and Standard; n=8 per quality grade) and six degrees of doneness (4, 25, 55, 60, 71, and 77°C). In the split-plot experiment, quality grade was the whole-plot, product-type was a sub-plot, and degree of doneness was the sub-sub-plot. The 3-way interaction of quality grade, degree of doneness, and product type impacted moisture (P = 0.004) and protein content (P = 0.006); pH (P < 0.001); neutral and polar lipid fatty acids (P ≤ 0.048); free and total amino acids (P ≤ 0.044); total reducing sugars (P < 0.001); and volatile compounds (P ≤ 0.029). The 2-way interaction of quality grade and degree of doneness impacted free amino acids (P ≤ 0.036); PUFA within the neutral lipid fraction (P ≤ 0.033); fatty acids within the polar lipid fraction (P ≤ 0.043); volatile compounds (P ≤ 0.038); and the total fat percentage (P = 0.046). The 2-way interaction of quality grade and product type impacted fatty acids within the neutral lipid fraction (P ≤ 0.042); fatty acids within the polar lipid fraction (P ≤ 0.015); and volatile compounds (P ≤ 0.047). The 2-way interaction of product type and degree of doneness affected fatty acids within the neutral lipid fraction (P ≤ 0.046); fatty acids within the polar lipid fraction (P ≤ 0.035); free amino acids (P ≤ 0.005) and total amino acids (P ≤ 0.004); volatile compounds (P ≤ 0.029); and cooking duration (P < 0.001). Overall the results of this study indicated that quality grade, grinding, and cooking have interacting effects on flavor related compounds. Thus, each factor must be considered during any model development which aims to predict beef flavor.
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Jefferies, Laura Kahealani. "Microbiological, Therman Inactivation, and Sensory Characteristics of Beef Eye-of-Round Subprimals and Steaks Processed with High-Pressure Needleless Injection." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/1047.
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High-pressure needleless injection (HPNI) is a process where small-diameter, high-velocity burst of liquid, penetrate foods at pressures ≤ 10,000 psi. The potential of HPNI as an enhancing technique for meat was studied. In study 1, HPNI translocated surface E. coli O157 into the interior of beef eye-of-round subprimals with an incidence of 40 (±7), 25 (±8), and 25 (±8)% for meat that had been surface-inoculated with a four-strain cocktail at 0.5, 1, and 2 log10 CFU/cm2, respectively. Run-off water contained 2, 2, and 3 log10 CFU/ml and was used for HPNI of additional subprimals, which resulted in a cross-contamination incidence of 83 (±4), 60 (±15), and 37 (±6) %, respectively. Incidence of translocation and cross-contamination was similar at all sampled levels below the inoculated surface. Study 1 results indicate that surface microflora will be translocated from the surface into the interior of HPNI-treated beef by the injection fluid and by cross-contamination with recycled fluid.
In study 2, E. coli was undetected in cooked steaks (63˚C internal) cut from subprimals inoculated with 2 log10 CFU/cm2 and HPNI processed (study 1). Although cooking reduced E. coli counts, determination of complete kill was not possible because the detection limit for bacterial recovery was about 1 log10 CFU/g. Steaks cut from HPNI-processed subprimals took longer (p <0.05) to reach 63˚C with grilling or broiling, compared to control steaks, possibly due to increased moisture in enhanced steaks.
In study 3, sensory acceptance of steaks was evaluated by a consumer panel. Appearance, flavor, and overall acceptance were similar among the untreated control, HPNI steaks, blade tenderized steaks (BT steaks), and steaks cut from subprimals that had been needle-injected with 0.35% (wt/vol) sodium tripolyphosphate using needle injection (NI-subprimal steaks) or HPNI (HPNI-subprimal steaks). Texture of BT steaks (6.5±1.9) was more liked than control steaks (5.8±1.8), while texture was similar for all other comparisons. Conversely, Warner-Bratzler shear force was NI-subprimal steaks < control < HPNI steaks = HPNI-subprimal steaks = BT steaks. Lack of correspondence between texture acceptance data and WBSF suggests that sensory scores were influenced by factors other than the force required for mechanical shear.
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Howard, Benjamin. "Effects of Implanting Strategy and Zilpaterol Hydrochloride on the Calpain Proteolytic System in Sectioned Beef Steaks for Two Time Periods." Thesis, North Dakota State University, 2016. https://hdl.handle.net/10365/28128.
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The objective of this study was to evaluate the impact of an anabolic implant and its use with the beta-adrenergic agonist zilpaterol hydrochloride (ZH) the calpain proteolytic system activity across specific areas of the beef strip steak over two aging days. Crossbred heifers were blocked by weight and randomly assigned to one of three treatments: 1) no implant or ZH (CON), 2) implant, no ZH (IMP), and 3) implant and ZH (IMP+ZH). At slaughter, strip steaks were collected and aged for 3 and 14 d. Samples were evaluated for Minolta objective color scores, pH, bioelectrical impedance analysis, and were then cut into lateral, lateral/medial, and medial sections. Protein was extracted from each section, and the calpain proteolytic system was evaluated. A day of aging effect was seen in protein degradation, along with a treatment by section interaction proteolytic activity. No differences were found in pH or color by treatment.
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Ye, Mu. "Use of chitosan-coated plastic films incorporating antimicrobials to control the growth of Listeria monocytogenes on ham steaks and cold-smoked salmon." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 133 p, 2008. http://proquest.umi.com/pqdweb?did=1597631391&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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McKillip, Kassandra. "Determination of the repeatability and accuracy of the Pressed Juice Percentage (PJP) method at sorting beef strip loin steaks into categories of known juiciness." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/32578.
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Master of ScienceDepartment of Animal Sciences and Industry
Travis G. O'Quinn
The objectives of this study were to determine the effect of enhancement on consumer and trained beef palatability scores of three quality grades when cooked to three degrees of doneness (DOD) and to determine the accuracy and repeatability of the Pressed Juice Percentage (PJP). Striploins of USDA Prime, Low Choice, and Low Select quality grades were used in this study. To maximize variation in juiciness, steaks were either enhanced (formulated for 108% pump with a solution of water, salt, and alkaline phosphates) or non-enhanced, and cooked to three degree of doneness (Rare: 60°C, Medium: 71°C, or Very Well-Done: 82°C). All samples were evaluated for Warner-Bratzler shear force (WBSF), Slice Shear Force (SSF), PJP, and palatability traits by consumer and trained panelists. Consumer panelists rated all enhanced treatments similar (P > 0.05) to each other and greater (P < 0.05) for juiciness, tenderness, flavor liking, and overall liking than all non-enhanced treatments. Consumer ratings of juiciness, tenderness, and overall liking scores increased (P < 0.05) as DOD decreased. Consumer panelists rated all enhanced treatments similar (P > 0.05) and greater (P < 0.05) for the percentage of steaks classified as premium quality. For trained panel initial juiciness, all enhanced treatments and non-enhanced Prime samples were similar (P > 0.05) and greater (P < 0.05) than other treatments cooked to Medium and Very Well Done. Results indicated PJP had a relatively high repeatability coefficient (0.70), indicating that only 30% of the variation observed was due to sample measurement differences. The PJP threshold values evaluated accurately segregated steaks by the probability of a sample being rated “juicy” by consumers, with the actual percentage of “juicy” samples determined to be 41.67%, 72.31%, 89.33%, and 98.08% for the <50%, 50 – 75%, 75 – 90%, and >90% categories, respectively. Therefore, enhancement has a substantial, positive effect on beef palatability. Enhancing higher quality beef does not provide an additional palatability benefit; hence the greatest economic advantage is in enhancing lower quality beef products. Results of this study indicate the PJP juiciness method is both repeatable and accurate at sorting steaks based on the likelihood of a steak being “juicy”.
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Daniel, Melissa Jean. "Effects of dietary vitamin A restriction on color shelf-life, lipid oxidation, and sensory traits of Longissimus lumborum and Triceps brachii steaks from early and traditionally weaned calves." Thesis, Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/487.
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Gomes, Carolina Lugnani. "Impact of end-point temperature of different heat transfer processes in sensory profile of beef strip loin steaks = Impacto da temperatura final interna em diferentes processos de transferênncia de calor no perfil sensorial de contrafilé bovino." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254241.
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Orientador: Helena Maria Andre BoliniTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Dois métodos de cocção (forno e chapa) e três temperaturas internas finais (65, 71 e 77°C) foram aplicados em contrafilé bovino (m. longissimus lumborum), com o objetivo de avaliar qual dos procedimentos proporciona a obtenção de um produto com perfil sensorial descritivo superior em relação à qualidade sensorial. As amostras de contrafilé, porção compreendida da 12º costela e a 2º vértebra lombar, de meias carcaças esquerdas de bovinos da raça Angus, da mesma idade e acabamento de gordura, foram coletadas e congeladas (-20ºC). Cada peça foi cortada em seis bifes de 2.54 cm, que foram embalados a vácuo e mantidos congelados. Os bifes foram distribuídos em seis tratamentos. Para a cocção, os bifes foram descongelados a 4°C por 24 horas antes das análises. As temperaturas internas foram monitoradas por meio de termopares inseridos no centro geométrico de cada bife. Para a perda de peso por cocção, houve interação significativa do método de cocção X temperatura interna final (p=0.002). O aumento da temperatura aumentou constantemente as perdas por cocção em ambos os métodos de cocção, de 65ºC para 77ºC. A 65ºC e 71ºC as perdas por cocção foram similares entre forno e chapa, enquanto a 77ºC, as amostras assadas no forno tiveram as maiores perdas, provavelmente devido ao longo tempo de preparo. Para a força de cisalhamento, não houve interação do método de cocção X temperatura interna final (p=0.54). Os bifes preparados a 65°C e 71ºC tiveram menores valores de WBSF (p<0,05), enquanto que aqueles preparados a 77°C tiveram valores maiores (p<0,05). Na análise de aceitação, a aparência, o aroma e o sabor tiveram maior aceitação nas amostras preparadas no forno elétrico em temperaturas mais altas, entretanto a maciez e a suculência tiveram maior aceitação nas amostras preparadas em temperaturas mais baixas, independente do método de cocção. Os bifes grelhados na chapa elétrica a 65°C foram melhores, porque proporcionaram a obtenção de uma amostra com aceitação significativamente superior em relação a todas as características sensoriais analisadas. Na Análise Descritiva Quantitativa, os bifes do forno e da chapa a 65°C foram principalmente caracterizados pelos atributos de aroma e sabor de sangue, sabor metálico, suculência, maciez, suculência aparente e cor interna vermelha. Na análise tempo-intensidade, a Imáx do estímulo maciez e suculência foi significativamente maior (p<0,05) no forno elétrico em relação à chapa elétrica. E em relação às temperaturas a Imáx das amostras submetidas a 65 e 71ºC não diferiram (p>0,05), mas diferiram (p<0,05) das amostras a 77ºC. O Ttot não foi diferente (p>0,05) para as amostras nos métodos de cocção e nas temperaturas internas finais para os estímulos de maciez e suculência. Portanto sugere-se que as diferenças encontradas pelos assessores na maciez e suculência das amostras, foram percebidas somente a primeira mordida (Imáx). E durante a mastigação até a fase de deglutição (Ttot) não variaram, indicando que as amostras permaneceram igualmente homogêneas em relação aos dois atributos após a primeira mordida
Abstract: Two cooking methods (oven and griddles) and three end-point temperatures (65, 71 and 77°C) were applied in beef strip loin (m. longissimus lumborum), to assess which of the procedures provides a product with superior descriptive sensory profile in order to the sensory quality. Strip loin samples with the similar degree of fat thickness from the 12th rib to the second lumbar vertebra of the left side of the carcass of similarly age Angus steers were collected and frozen (-20ºC). Each piece was cut into six 2.54 cm thick steaks. The steaks remained vacuum packed and frozen. For cooking, the steaks were thawed at 4°C for 24 hours. The internal temperatures were monitored by thermocouples inserted in the geometric center of each steak. The interaction between cooking method and end-point temperature had a significant (P=0.002) impact on cooking loss. The increasing end-point temperature, constantly increase levels of cooking loss in both cooking methods, from 65ºC to 77ºC. At 65ºC and 71ºC the cooking loss were similar between oven and griddle, while at 77ºC the oven had the great loss, probably due to the long cooking. The interaction between cooking method and end-point temperature did not significantly impact (P=0.54) shear force. The steaks prepared at 65°C and 71ºC had lower (P<0.05) shear force values, while those prepared at 77°C had higher values (P<0.05). In acceptance analysis of appearance, aroma and flavor, samples cooked in electric oven, at higher temperatures, had the greater acceptance, however the tenderness and juiciness had greater acceptance in samples prepared at lower temperatures, regardless the method of cooking. Steaks grilled on the counter-top griddles at 65°C yielded a sample with a significantly greater acceptability in terms of all of the sensory characteristics analyzed. For Descriptive Quantitative Analysis, steaks prepared in oven and griddles at 65°C were mainly characterized by a blood aroma and flavor, a metallic flavor, juiciness, initial tenderness, apparent juiciness and internal red color. In the time-intensity analysis, the Imax values for tenderness and juiciness stimuli was higher (P<0.05) for the samples subjected to the electric oven as compared to the electric griddles. Regarding the temperatures, although the Imax for tenderness and juiciness of the samples subjected to temperatures of 65 and 71ºC were not different (P>0.05), it differed (P<0.05) from the samples at 77ºC. The Ttot value was not different (P>0.05) for both cooking methods and end-point temperatures in relation to the stimuli tenderness and juiciness. It can be suggested that the differences on tenderness and juiciness found by the assessors were noted only at first bite (Imax). Perception of tenderness and juiciness during chewing to swallowing (Ttot) did not vary, indicating that the samples remained homogeneous for both attributes after the first bite
Doutorado
Consumo e Qualidade de Alimentos
Doutora em Alimentos e Nutrição
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Petit, Maxime. "Residency and trafficking of ILC2 in steady steate and th2 induced inflammatory conditions." Thesis, Université de Paris (2019-....), 2019. http://www.theses.fr/2019UNIP7095.
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Les ILC2s sont retrouvées au niveau des muqueuses comme les poumons et l’intestin, ainsi que dans divers ganglions et organes liés au métabolisme comme les tissus adipeux (ATs). Elles jouent un rôle important dans l’induction des réponses immunitaires de type Th2 comme équivalents innées dans lymphocytes Th2. Elles sont activées par des alarmines (IL-25 et IL-33) et des activateurs environnementaux (allergènes, métabolites et neuromédiateurs). Les ILC2s sécrètent des cytokines de type Th2 permettant de recruter et d’activer des cellules myéloïdes, d’augmenter la production de mucus et la contraction musculaire, ainsi que d’initier la réparation et le renouvellement des tissus. Cependant, une activation non contrôlée des ILC2s participe au développement de maladies chroniques. Les ILCs sont généralement considérées comme des cellules résidentes. Cependant, plusieurs études ont suggéré que la migration pourrait être un processus important pour la maturation des capacités effectrices. La circulation des ILCs reste peu documentée, et aucun mécanisme n’est pour l’instant capable d’expliquer le renouvellement des ILC2s pour agir dans de nombreux tissus suite à une stimulation. Nous avons montré que des quantités significatives d’ILC2s matures et immatures peuvent être collectées dans la lymphe du canal thoracique de souris canulées durant plusieurs heures. Les ILC2s circulantes forment 3 groupes distincts avec des expressions de molécules d’adhésion et récepteurs de migration spécifiques. Nos expériences de transferts cellulaires montrent que ces groupes spécifiques de molécules exprimées sont liés à des tropismes particuliers pour l’intestin, les poumons ou les ATs. Pour analyser le comportement des ILC2s dans un contexte de réponse de type Th2, nous avons injecter les cytokines IL-25 et IL-33 et étudié la lymphe de ces souris. La stimulation à l’IL-33 augmente le nombre de cellules ILC2s circulants dans la lymphe. Les différents groupes d’ILC2s montrent des réponses différentes à l’IL-33. Ainsi, les ILC2s migrants vers l’intestin sont majoritairement prolifératives tandis que le groupe migrant vers les poumons et les ATs secrètent de l’IL-5, de l’IL-13 et de l’Areg. Cela suggère que les ILC2s migrants de façon spécifique possèdent une empreinte fonctionnelle. Nous confirmons les fonctions des groupes d’ILC2s circulants en utilisant des modèles plus physiologiques mimant des réactions allergiques et des infections parasitaires (stimulation par la papaïne et le succinate). Les migrations vers l’intestin et les poumons jouent un rôle primordial dans l’induction de réponse de type Th2 par sécrétion d’IL-5 et d’IL-13, et à l’initiation de la réparation tissulaire par production d’Areg. De façon intéressante, les ILC2s migrants vers les poumons participent au renouvellement des populations résidentes participant principalement à la production d’Areg. Finalement, nous caractérisons un rôle important du trafic des ILC2s à différents temps suivant l’infection par Nippostrongulus brasiliensis, confirmant la fonction des ILC2s migrantesILC2s are found in mucosal tissues as lung and intestine, in lymph nodes, and in metabolic tissues such as the adipose tissues. They play important role in maintaining or inducing type-2 immune responses as innate equivalent of Th2 lymphocytes. They are activated by alarmins (IL-25 and IL-33) and by external activators (allergens, metabolites and neuromediators). ILC2s are secreting type-2 cytokines to facilitate the activation of other cells and to induce an important repair program. Their activation allows large type of events as diverse as myeloid cells recruitment and activation, mucus production, muscle contractility and tissue repair. They have key role in lung and adipose tissue development and maintain their homeostasis by early responding against parasitic pathogens. Abnormal activation of ILC2s is also participating to chronic diseases.ILCs are mostly considered as resident cells. However, different studies suggested that migration could be important for the maturation of their effector capacities and to correctly target the injured tissue. Circulation and trafficking of ILC subsets is still unclear. No mechanism is yet available to explain the turnover of ILC2s and how they can act in many tissues following stimuli.We found that large numbers of mature and immature ILC2s could be collected in the thoracic duct lymph of mice perfused over several hours, showing that ILC2s are in fact actively circulating through the hemo-lymphatic circuit. Furthermore, circulating mature ILC2s could be separated into three distinct subsets depending on their pattern of receptor and adhesion molecule expression. Cell transfer experiments proved that specific patterns are representative of specific tropism for gut, lung and adipose tissues.To analyse ILC2 behaviour in the context of a type-2 response, we injected IL-25 and IL-33 before lymph collection. IL-33 stimulation largely enhanced the number of circulating ILC2s in the lymph. These different ILC2 tissue targeted subsets responded differently to IL-33. Specifically, gut-trafficking ILC2s were mainly stimulated to proliferate whereas lung and adipose tissue subsets were stimulated to produce IL-13, IL-5 and Areg. This suggests that, in ILC2s, specific tissue targeting is associated with already imprinted functions while transiting through the hemo-lymphatic system. We confirmed these functions of circulating ILC2 subsets in more physiological context by mimicking allergy and helminth infection (stimulation by papain and succinate) where specific migration to lungs and intestine play important roles in mounting the type-2 response by IL-5/IL-13 secretion, and also initiating tissue repair by Areg production. Interestingly, we showed that lung migrating ILC2s participated to resident pool renewal that main function is Areg production. Finally, we characterized important trafficking of ILC2 at different stages of Nippostrongulus brasiliensis infection, confirming the functional relevance of ILC2 trafficking
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Söderberg, Sara. "Steamy, steady & sanctuary : The importance of crafting a shared sauna at Sunds Grustag." Thesis, Konstfack, Keramik & Glas, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-7717.
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Ihlaseh, Shadia Muhammad [UNESP]. "Análise da expressão dos genes STEAP1 e STEAP2 em adenocarcinomas de próstata por RT-PCR quantitativa em tempo real." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/95903.
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ihlaseh_sm_me_botfm.pdf: 228425 bytes, checksum: d8ddb66a9f9af259ca5de94c447588a1 (MD5)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O câncer de próstata (CaP) é um problema de saúde pública devido suas altas taxas de incidência e de mortalidade. Atualmente, os marcadores disponíveis para o diagnóstico e prognóstico não são capazes de diferenciar os CaPs indolentes dos que progridem mais agressivamente. Estudos moleculares usando análises em larga escala, como hibridação genômica comparativa baseada em arrays (aCGH), permitem a identificação de vários genes candidatos a marcadores. Estudos prévios de nosso grupo usando hibridação aCGH em CaP demonstraram amplificação em 7q21.13, onde estão mapeados os genes STEAP1 e STEAP2 (sixtransmembrane epithelial antigen of prostate 1 e 2). Esses genes apresentam expressão aumentada em diversas linhagens de células neoplásicas, incluindo as de próstata. No entanto, seu papel no desenvolvimento e progressão do CaP permanece desconhecido. Há evidências de que eles codificam antígenos tumorais com potencial para serem utilizados como marcadores prognósticos. O presente trabalho visou determinar o perfil de expressão dos genes STEAP1 e STEAP2 por RT-PCR quantitativa em tempo real (qRT-PCR) em adenocarcinomas primários de próstata, em amostras de tecido não-neoplásico adjacente aos tumores e em hiperplasias nodulares da próstata (HNP). Amostras de próstatas avaliadas histologicamente como normais foram obtidas de necropsias e usadas como controles. Os pacientes foram agrupados em três classes segundo o risco de recorrência do tumor (baixo, moderado e alto) de acordo com o PSA (antígeno prostático sérico), a graduação histológica e o estadiamento dos tumores. Foi observado aumento de expressão dos genes STEAP1 e STEAP2 em 28% e 38% das amostras, respectivamente; em três pacientes com alto risco de recorrência houve aumento simultâneo da expressão dos dois genes. A expressão...
Available prognostic markers as serum PSA levels, Gleason differentiation scores and tumor staging have not been able to discriminate indolent from aggressive tumors. Increased expressions of STEAP1 and STEAP2 genes (six-transmembrane epithelial antigen of prostate 1 e 2) have been shown in neoplastic cell lineages from prostate, urinary bladder, ovary and other tumors. Previously, using comparative genomic hybridization based in arrays in prostate adenocarcinomas and their metastasis, we described genomic gains at the 7q21.13. In this region are mapped the STEAP1 and STEAP2 genes. The involvement of these genes in PCa development and progression remains to be clarified. These genes possibly express tumoral antigens and are putative molecular markers.The objective of the present study was to determine the gene expression profiles of the STEAP1 e STEAP2 genes by real time quantitative PCR in primary prostate adenocarcinomas, surrounding non-neoplastic tissues, and in nodular hyperplasia of the prostate. The results were associate with tumor pathologic characteristics and patients clinical features. Samples from histologically confirmed normal prostates obtained from necropsies were used as normal controls. According to potential risk for tumor recurrence (low, moderate and high risk) patients were classified in three groups depending on the serum PSA levels, Gleason scores, and tumor stages. Increased expression of STEAP1 e STEAP2 genes were registered in 28% and 38% of samples, respectively; both genes presented simultaneously increased expression level in three high-risk cases. Similar pattern of expression were detected in the majority of CaP (Spearman r=0,63; p<0,0001) and non-neoplastic surrounding tissue (Spearman r=0,78; p=0,0002) samples. Compared to the non-neoplastic surrounding tissues there was significant increase of STEAP1 gene expression in PCa samples... (Complete abstract click electronic access below)
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Ihlaseh, Shadia Muhammad. "Análise da expressão dos genes STEAP1 e STEAP2 em adenocarcinomas de próstata por RT-PCR quantitativa em tempo real /." Botucatu : [s.n.], 2008. http://hdl.handle.net/11449/95903.
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Resumo: O câncer de próstata (CaP) é um problema de saúde pública devido suas altas taxas de incidência e de mortalidade. Atualmente, os marcadores disponíveis para o diagnóstico e prognóstico não são capazes de diferenciar os CaPs indolentes dos que progridem mais agressivamente. Estudos moleculares usando análises em larga escala, como hibridação genômica comparativa baseada em arrays (aCGH), permitem a identificação de vários genes candidatos a marcadores. Estudos prévios de nosso grupo usando hibridação aCGH em CaP demonstraram amplificação em 7q21.13, onde estão mapeados os genes STEAP1 e STEAP2 (sixtransmembrane epithelial antigen of prostate 1 e 2). Esses genes apresentam expressão aumentada em diversas linhagens de células neoplásicas, incluindo as de próstata. No entanto, seu papel no desenvolvimento e progressão do CaP permanece desconhecido. Há evidências de que eles codificam antígenos tumorais com potencial para serem utilizados como marcadores prognósticos. O presente trabalho visou determinar o perfil de expressão dos genes STEAP1 e STEAP2 por RT-PCR quantitativa em tempo real (qRT-PCR) em adenocarcinomas primários de próstata, em amostras de tecido não-neoplásico adjacente aos tumores e em hiperplasias nodulares da próstata (HNP). Amostras de próstatas avaliadas histologicamente como normais foram obtidas de necropsias e usadas como controles. Os pacientes foram agrupados em três classes segundo o risco de recorrência do tumor (baixo, moderado e alto) de acordo com o PSA (antígeno prostático sérico), a graduação histológica e o estadiamento dos tumores. Foi observado aumento de expressão dos genes STEAP1 e STEAP2 em 28% e 38% das amostras, respectivamente; em três pacientes com alto risco de recorrência houve aumento simultâneo da expressão dos dois genes. A expressão... (Resumo completo, clicar acesso eletrônico abaixo)Abstract: Available prognostic markers as serum PSA levels, Gleason differentiation scores and tumor staging have not been able to discriminate indolent from aggressive tumors. Increased expressions of STEAP1 and STEAP2 genes (six-transmembrane epithelial antigen of prostate 1 e 2) have been shown in neoplastic cell lineages from prostate, urinary bladder, ovary and other tumors. Previously, using comparative genomic hybridization based in arrays in prostate adenocarcinomas and their metastasis, we described genomic gains at the 7q21.13. In this region are mapped the STEAP1 and STEAP2 genes. The involvement of these genes in PCa development and progression remains to be clarified. These genes possibly express tumoral antigens and are putative molecular markers.The objective of the present study was to determine the gene expression profiles of the STEAP1 e STEAP2 genes by real time quantitative PCR in primary prostate adenocarcinomas, surrounding non-neoplastic tissues, and in nodular hyperplasia of the prostate. The results were associate with tumor pathologic characteristics and patients clinical features. Samples from histologically confirmed normal prostates obtained from necropsies were used as normal controls. According to potential risk for tumor recurrence (low, moderate and high risk) patients were classified in three groups depending on the serum PSA levels, Gleason scores, and tumor stages. Increased expression of STEAP1 e STEAP2 genes were registered in 28% and 38% of samples, respectively; both genes presented simultaneously increased expression level in three high-risk cases. Similar pattern of expression were detected in the majority of CaP (Spearman r=0,63; p<0,0001) and non-neoplastic surrounding tissue (Spearman r=0,78; p=0,0002) samples. Compared to the non-neoplastic surrounding tissues there was significant increase of STEAP1 gene expression in PCa samples... (Complete abstract click electronic access below)
Orientador: João Lauro Viana de Camargo
Coorientador: Silvia Regina Rogatto
Banca: Maria Inês Pardini
Banca: Luciano João Nesrallah
Mestre
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Abdullah, Hishyar K. "Steady rivulets." Thesis, University of Essex, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328593.
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Sackmann, David. "A Piece of Steak: A Chamber Opera." Thesis, University of Oregon, 2017. http://hdl.handle.net/1794/22286.
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A Piece of Steak is a chamber opera in four scenes based on the Jack London short story of the same name. The piece is composed for five operatic soloists, a chorus, a voice actor, and a Pierrot ensemble with percussion, and is 25-30 minutes in duration. The libretto that I have written for this piece follows an aging boxer and his wife as he prepares for an important match for the future of his family. The characters in A Piece of Steak deal with issues related to poverty, family, and the broader sports culture and the treatment of athletes.
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Ahmed, Kamel Abd El-Salam Attia. "Automobile cornering behaviour under steady and non-steady state conditions." Thesis, University of Leeds, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329475.
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Sahay, Sunil Kishore. "The austenite → ferrite transformation in tungsten steels and some other ternary steels." Thesis, University of Cambridge, 1986. https://www.repository.cam.ac.uk/handle/1810/221895.
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Zaidi, Syed Khateeb. "Studies on steady state and post-steady state ultrafiltration of different solutes." Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6271.
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Concentration polarization in ultrafiltration with fully retentive membrane under unstirred conditions has been studied using three different types of solutes: (a) solute which exerts osmotic pressure and also forms a gel (polyethylene glycol), (b) solute which exerts osmotic pressure but does not form a gel (dextran) and (c) solute which does not exert osmotic pressure but forms a gel (silica). An unequivocal determination of whether pressure independent flux regime is osmotically controlled or gel layer dominated, is still open for discussion in the membrane literature. The present work reports a method that could be used to address this issue. It is shown that analysis of post steady state transient filtration data leads to clear demarcation of osmotically limited and gel layer controlled filtration. A method for determining additional filtration resistance offered by the polarization layer to permeate flow in macromolecular ultrafiltration has been proposed and verified experimentally. It has also been shown that the polarization layer thickness is not sensitive to the feed pressure but varies as a function of the bulk solute concentration; higher the bulk concentration thicker is the polarization layer. A fundamental analysis of deposited gel layer has been presented based on constant pressure filtration theory for the solute, which only forms a gel layer (silica). This was used to calculate specific resistance of the solute particles. The concentration and pressure dependence of specific resistance was also reported while silica gel porosity was determined by the Kozeny-Carman equation.
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Bozsak, Franz. "Optimisation de stents actifs." Phd thesis, Ecole Polytechnique X, 2013. http://pastel.archives-ouvertes.fr/pastel-00858100.
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L'utilisation de stents actifs (DES) a révolutionné le traitement de l'athérosclérose. Le relargage contrôlé de médicaments anti-prolifératifs dans la paroi artérielle (PA) a permis de réduire fortement le taux de resténose intra-stent. Mais le risque de thromboses intra-stents tardives demeure un enjeu majeur des DES en partie lié au retard de cicatrisation de la PA endommagée lors de l'implantation. Cette thèse présente une méthode d'optimisation du design des DES afin d'inhiber la resténose sans affecter la cicatrisation. Pour quantifier la performance des différents designs, un modèle numérique décrivant l'écoulement sanguin et le transport de médicaments dans les artères stentées a été développé. Il prend en compte la structure multi-couches de la PA et les interactions du médicament avec les cellules. Un algorithme d'optimisation est couplé au modèle afin d'identifier les DES optimaux. L'optimisation du temps de relargage ainsi que de la concentration initiale du médicament dans le revêtement du DES ont un effet significatif sur la performance. Lorsque le médicament utilisé est le paclitaxel, les solutions optimales consistent à relarguer le produit à des concentrations nettement inférieures à celles des DES actuels soit pendant quelques heures, soit pendant une durée d'un an. Pour le sirolimus, un relargage lent est nécessaire. Les formes optimales des spires du DES sont toujours allongées mais profilées seulement lorsque le relargage est rapide. Ces résultats permettent d'expliquer en partie les performances des différents DES récents et révèlent un fort potentiel d'amélioration dans la conception des DES par rapport aux dispositifs commerciaux actuels.
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Cochrane, Hal. "Formable dual-phase steels." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329964.
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McGinty, Sean. "Stents and arterial flows." Thesis, University of Strathclyde, 2010. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=12396.
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Harvey, M. T. "Laser welding of steels." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603824.
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One of the aims of the study has been the evaluation of suitable wires for welding API-X80 and En8 grade steels, on the basis of experimental results. The experimental results (from Charpy, CTOD and tensile testing together with general microscopy) were obtained using commercially available flux and metal cored wires. Weld metal tensile properties similar to those of the parent metal were obtained, although the fracture properties were generally inferior. An exception to this was shown by the En8 steel welded with a high nickel content wire which exhibited toughness values greater than those recorded for the parent metal. However, the high nickel content makes the use of such a weld in certain corrosive environments problematic. The best toughness properties amongst the X80 welds were shown by the higher oxygen containing welds. For these X80 welds, mechanical test results correlated strongly with microstructure, which varied from coarse to fine ferrite. In order to improve the toughness properties, experimental wires were produced using a combination of computer modelling (weld prediction program) and statistical methods (Taguchi methods). These provided successful in that significant proportions of acicular ferrite were obtained. However, the toughness values did not show a corresponding improvement. This was believed to be due to the presence of inclusions, essential in order to nucleate acicular ferrite, but which have a direct effect on the fracture resistance of the weld metal. The presence of grain boundary ferrite morphologies, microphases and nitrogen may also have had an embrittling effect. It was suggested that reducing the oxygen levels and controlling the presence of other elements would have a beneficial effect with regard to toughness properties. Finally the problem of Fracture Path Deviation (FPD), where the crack path deviates out of weld metal during Charpy impact testing, was examined using autogenous and wire feed welds produced in BS 4360 50B steel. To examine the factors controlling FPD, both experimental work and finite element modelling of the Charpy specimen were undertaken. The results indicated the importance of weld width and orientation on the FPD phenomena. It was suggested that the toughness testing of narrow fusion zone laser welds (approximately 2 to 3 mm) should be undertaken using CTOD rather than Charpy testing.
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Mohamed, Z. M. E. Q. "Hot ductility of steels." Thesis, City University London, 1988. http://openaccess.city.ac.uk/8348/.
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The hot tensile test has been used for a variety of steels, to investigate the influence of such factors as inclusions, precipitation, phase transformation and grain size on hot ductility. Tests were performed in the temperature range 700-1000 °C and at a strain .4 _2 1 rates of (10 —10 S ), generally to simulate the conditions experienced during the straightening operation in the continuous casting process in which transverse cracks propagate. Two zones of reduced ductility can be identified. The Y-a transformation zone which has been shown to produce a significant ductility trough due to strain concentration in the softer ferrite films surrounding the V grains, cating voiding around he MnS inclusions which link to give intergranular failure, and factors which alter the A3 temperature, such as carbon content, have been shown to produce a change in the temperature at which the ductility trough occurs. The second zone of reduced hot ductility was observed in the austenite region, due to the retardation of dynamic recrystallisation associated with the presence of fine carbides, nitrides and/or inclusions precipitates at the austenite grain boundaries, which allows intergranular cracks to develop. The depth and width of this ductility trough is primarily dependent on the size and amount of precipitates present. The influence of MnS inclusions in reducing hot ductility has been noted above and below the Ae3 temperature. Above the Ae3 , inclusions act in a similar way to fine precipitation preventing dynamic recrystallisation and below the Ae3 , they offer more sites for micro-voiding to occur. Although grain size refinement improves ductility, it does so as long as similarity in precipitate volume fraction and size exist. Improved hot ductility has been achieved by adding Ca to the steel which reduces the amount of l9nS inclusions precipitated during cooling from solution temperature at the austenite grain boundaries.
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Birkett, Ailsa Jacqueline. "Barkhausen noise in steels." Thesis, Durham University, 1988. http://etheses.dur.ac.uk/6455/.
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A survey of the methods of observing Barkhausen noise was made and a suitable system of measurement Identified for laboratory measurements to be carried out on steel samples. A coil system to measure the Barkhausen noise from samples was constructed. The noise was sampled and recorded to microcomputer by means of a transient recorder. The experimental parameters were selected to optimise the data. A Fast Fourier Transform was performed on the noise data by means of a library routine on a mainframe computer and the results plotted as the power spectra of the data. The recorded voltage profile of the noise was also plotted. The system was verified by use of grain oriented silicon iron samples. The power spectra and voltage profiles were plotted and, when compared with the results of other workers, were found to be favourable. Tests were performed on constructional steel samples. The power spectra and voltage profiles from the constructional steels were considered with the coercivity and remanence of the steels and a relationship sought. No simple general relationship was identified although empirical relationships were suggested for some of the data. A knowledge of the microstructure of the steel is required to explain some of the results. The power spectra and voltage profiles were assessed in terms of the hysteresis loop shape and influence of microstructure on the value of coercivity. It was found that these were the influencing factors in the Barkhausen noise. The effect of plastic deformation on power spectra was investigated. Results of an industrial investigation were reported.
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Abu, Shousha R. I. "Hot ductility of steels." Thesis, City University London, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305120.
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Jilabi, Abdulsameea. "Welding of rail steels." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/welding-of-rail-steels(b9d907ef-45fc-4649-8c2f-9239a121abe0).html.
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The worldwide preferred method for rail joining is welding; flash butt welding (FBW) and thermite welding (TW) are the two main welding methods used for joining continuous welded rail (CWR) tracks. However, the welds still represent a discontinuity in the track structure due to variations in microstructure, mechanical properties and residual stress levels with respect to the parent rail. These variations can play significant roles in increasing the risk of weld failure under service conditions. In order to better understand how FBW parameters affect these variations, the two main parameters; number of preheating cycles and upsetting forces were varied in three 56E1 rail welds, welded by a stationary FBW machine. Besides, these variations were systematically compared with those that occur in a standard thermite 60E2 rail weld. The thermite weld showed a heat affected zone (HAZ) extent much greater than those measured in the flash butt welds. The flash butt rail weld with a greater upsetting force (Standard Crushed) showed a HAZ extent larger than those in the other two welds (Standard Uncrushed and Narrow-HAZ Crushed), while the weld with fewer preheating cycles (Narrow-HAZ Crushed) showed a smaller extent of the HAZ.All welds showed pearlite colonies with proeutectoid ferrite at the prior austenite grain boundaries in the weld centre, and in the thermite weld zone. The rest zones across the welds exhibited almost fully pearlitic microstructures, but the pearlite at nearly the visible HAZ extents was partially spheroidised. The partially spheroidization zone had the minimum hardness across each of the thermite and flash butt welds. The Narrow-HAZ Crushed weld showed hardness in the weld centre, on average, higher than that of the parent metal. Moreover, the averaged hardness levels in this weld were significantly higher than those in the other two welds. However, these levels in the Standard Crushed weld were slightly lower than those in the Standard Uncrushed weld. Although the visible HAZ extent coincided with the point of minimum hardness, the residual stresses arising from the welds seem to extend much further. Contour Method and laboratory X-ray diffraction techniques were used together to measure the residual stress components across the thermite and flash butt rail welds. The longitudinal residual stress distribution showed tension in the web region along with compression in the head and foot regions of the rail welds. The vertical stress distribution across the flash butt welds was generally similar, and the maximum tensile stress values were comparable to those in the longitudinal direction. While the maximum values of the longitudinal tensile stress increased with decreasing the HAZ widths, these values in the vertical direction were significantly unaffected. However, the longitudinal and vertical tensile residual stresses typically promote the vertical straight-break and horizontal split web failure modes respectively.
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Ray, Arunim. "Niobium microalloyed rail steels." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/265387.
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Rail steels rely primarily on possessing adequate wear and rolling contact fatigue resistance. These properties, together with the toughness, can in principle be optimized by implementing thermomechanical processing assisted by controlled niobium additions. The purpose of the current work is to develop a Nb-microalloying strategy in the context of high-carbon pearlitic and cementite-free bainitic steels. The conventional methods do not leave the critical regions of a rail section in a suitably processed state. An attempt has been made for the first time, to create a pancaked austenite grain structure, with an examination of the consequences on the final product. One of the major difficulties is to ensure that niobium does not segregate during manufacturing, since niobium is a strong carbide former and rail steels traditionally contain large carbon concentrations. Niobium solubility in austenite has been assessed critically and thermodynamic calculations for microsegregation have been taken into account. The aim is to ensure that any primary niobium carbide precipitated from solute-enriched liquid during non-equilibrium solidification, can be taken into solution in austenite during reheating, to mitigate potential effects of coarse precipitates on the final mechanical properties. Rail steels containing 0.01-0.02 wt% Nb have been designed and characterised. In as-cast condition, primary niobium carbides as large as ~10 µm can be observed, which dissolve slowly during reheating. An attempt has been made to develop a model to estimate the dissolution kinetics of the carbides. Dissolved niobium in reheated austenite precipitates during hot deformation as fine niobium carbides (< 50 nm) which inhibit austenite recrystallisation by pinning the austenite grain boundaries. Nb-microalloying increases the ‘no-recrystallisation temperature’ of deformed austenite during multi-pass compression tests. The topology of grain deformation has been analysed in terms of stereological calculations and dilatometric experiments have shown that transformation kinetics tend to accelerate when the austenite is deformed below the no-recrystallisation temperature, however the effect is relatively small. The microstructure and mechanical properties of the as-rolled Nb-microalloyed steels have been characterised along with their rolling-sliding wear performance and compared with their non-microalloyed counterparts. Increased austenite grain boundary area and increased dislocation activity due to pancaking, hinder bainite growth which leads to an increased retained austenite volume fraction. This in turn, leads to slightly improved ductility, improved toughness and improved wear resistance in Nb-microalloyed bainitic alloys. Microstructural refinement in Nbmicroalloyed pearlitic alloys does not have any significant effect on tensile and toughness properties, but wear resistance improves significantly. A Bayesian neural network model has been developed to estimate the wear of rails. Predicted trends have been found consistent with metallurgical experience and the perceived noise levels are consistent with reasonable repeatability of the wear testing method used. The model can be applied widely to estimate wear because of its capacity to indicate uncertainty, including both the perceived level of noise in the output, and an uncertainty associated with fitting the function in the local region of input space.
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Elliott-Bowman, Bernadette. "Electropulsing of pearlitic steels." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/44560.
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Electropulsing is a process characterised by the application of short duration (~100μs) electrical current pulses. The process is claimed to be capable of stimulating microstructure change in a variety of metals at low temperatures and energy levels. In this thesis, electropulsing is applied to examine its potential to produce nanostructured, strong yet ductile pearlitic steel. Electropulsing of cold-rolled 0.92wt%C pearlitic steel plate was conducted at room temperature across a range of variables (J ~ 10⁷ - 10⁹ A·m-2, f ~ 1 - 100Hz, d ~ 80 - 160μs, N ~ 1 - 90000), in order to identify the parameters required to induce microstructure change. A microstructure of equiaxed ferrite and spheroidised cementite was obtained under high frequency, current density and pulse duration electropulsing. Martensitic transformation and Widmanstätten structures were also observed. No microstructure change was produced by electropulsing treatments of low current density, frequency and pulse duration. Elevated temperature electropulsing tests on 0.73wt%C pearlitic rod, which combined pulsed current treatments (J ~ 10⁷ A·m-2) with furnace annealing (660-740°C), were conducted to attempt to overcome any initial energy barrier threshold, in order to highlight any current-based athermal effects. Grain size analysis did not reveal any variation between electropulsed and furnace treated samples. Secondary, transmission and backscatter electron microscopy were used for microstructure characterisation, and mechanical and electrical properties were also experimentally determined. Atom probe tomography was applied to select samples to analyse the steel composition after electropulsing. Resistive heating-based temperature effects were calculated and compared with similarly treated Gleeble-processed samples, to understand the impact of heating rate on the microstructures observed. Electropulsing was determined to have influenced the microstructure of pearlitic steel through resistive heating. An athermal mechanism could not be clearly discerned.
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Turkeli, Altan. "Microsegregation in manganese steels." Thesis, University of Sheffield, 1990. http://etheses.whiterose.ac.uk/15023/.
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Dendritic morphology and microsegregation in the ternary Fe- 1.6% Mn - 0.1 to 0.8 % C alloys have been investigated by quenching the unidirectionally solidified specimens. The microprobe analysis of these specimens showed that the manganese segregation was significantly controlled by the back diffusion. This back diffusion was extremely high in the case of ferritic solidification whereas only a small rise in Cmin was obtained for the austenitic phase. It was found that the manganese microsegregation between the primary arms was always higher than between the secondary arms. The measured segregation ratios indicated a rise with increasing carbon content for both morphologies. No clear effect of cooling rate on segregation was seen for secondary arms and only a sliqht increase was recorded with increasing the cooling rate for primary arms. Secondary dendrite arms solidified to produce asymmecric distribution profiles (saw-tooth or TGZM effect). Measurements of the secondary dendrite arms during qrowth showed that the rate of the coarsening in these manganese steels was higher than other steels resulting in high homogenization between the arms . No tertiary arms have been observed. The primary arms grew mainly in the so-called 'close packed' arrangement and their spacinq did not chanqe with time. By increasing the qrowth rate and the temperature qradient in the liquid a decrease in primary arm spacings was seen. The results agree well with available experimental data in the literature. The microsegregation calculations obtained from the secondary dendrite arm coarseninq model is in a very good agreement with the experimental measurements. The same model without arm coarsening was applied to different primary arm morphologies and the predictions of these models are also in reasonable agreement with observations.
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Onyuna, Musa Omollo. "Deformation behaviour and martensitic transformations in metastable austenitic steels and low alloyed multiphase steels." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2009. http://nbn-resolving.de/urn:nbn:de:swb:105-7223495.
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Es wurden die Mikrostruktur und die mechanischen Eigenschaften bedingt durch dehnungsinduzierte Martensitbildung im metastabilen austenitischen Stahl X5CrNi18.10 und in einem niedrig legierten Mn-Si-Al Stahl untersucht. Dazu wurden Zugversuche bei verschiedenen Temperaturen durchgeführt. Für den Stahl X5CrNi18.10 wird auf der Grundlage der Arbeit von Ludwigson und Berger ein Modell zur Beschreibung des Umwandlungsverhaltens als Funktion der Dehnung und der Temperatur entwickelt. Es kann weiterhin gezeigt werden, dass die erreichbare Gleichmaßdehnung in diesen Stahl durch eine maximal ertragbare Umformarbeit bestimmt wird. Die erhaltenen Fließkurven konnten mit Hilfe der FEM und einer modifizierten Mischungsregel für die Festigkeit erfolgreich modelliert werden. Die Ergebnisse für den Mn-Si-Al Stahl zeigen, dass neben dem Restaustenit, das Verbundverformungsverhalten der anderen Gefügebestandteile (Ferrit, Bainit, Martensit) wichtige Faktoren für die Optimierung der mechanischen Eigenschaften darstellen.
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Wombacher, Ralf. "Polymere als Beschichtungsmaterialien für Stents." [S.l.] : [s.n.], 2003. http://archiv.ub.uni-marburg.de/diss/z2003/0095/.
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Papaefthymiou, Spyros. "Failure mechanisms of multiphase steels /." Aachen : Shaker, 2005. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=014183924&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Hekkanen, Mikko. "Inclusion Rating of Clean Steels." Thesis, Örebro University, Department of Technology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-7786.
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The main part of this work has been a literature survey, reviewing scientifical reports forinformation on how steel cleanness is evaluated today, and also how the steel cleanness is related tothe fatigue performance of clean steels.
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Andersson, Roger. "Deformation characteristics of stainless steels /." Luleå : Luleå University of Technology, 2005. http://epubl.luth.se/1402-1544/2005/12.
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Sprinkle, Jim. "Feeding Management for Show Steers." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2009. http://hdl.handle.net/10150/144708.
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12 pp.Large frame steers weigh from 1200 to 1400 pounds at finish weight, while medium frame steers are only around 700 pounds. This publication discusses how to select and feed a steer in order to get it to its' desired weight.
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Grimanelis, Dimitris. "Tribological behaviour of sintered steels." Thesis, Brunel University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294944.
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Tsakiris, V. "Deformation twinning in austenitic steels." Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371586.
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Sullivan, J. H. "Metallic runoff from coated steels." Thesis, Swansea University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639132.
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An investigation was carried out to assess levels of metallic runoff, particularly zinc, from the surface and cut-edges of a variety of commercial coated steels in order to ascertain potential environmental effects in line with the ongoing EU risk assessment into zinc (1995). Zinc runoff was monitored from the surfaces of a range of zinc-coated steels with sealed edges over 19 months at two UK weathering sites. The composition of the zinc coating is crucial in determining materials performance and rainfall levels are critical in determining runoff quantity. Observed zinc runoff levels are generally below the permissible drinking water level for humans but runoff levels in the harshest environment exceed this maximum for some materials during the exposure. A range of organically coated galvanised steels were exposed for 27 months at three UK weathering sites with a large cut-edge length to assess runoff from such edges. Runoff was high in initial months with zinc levels reducing with time due to the build up/action of corrosion products and corrosion inhibitors. Zinc levels were below the permissible drinking water level. Zinc runoff measured over 3 months can more accurately predict long-term organic coating delamination than salt spray and prohesion testing. Accelerated laboratory tests using a distilled water electrolyte were developed that predict long-term external weathering runoff from panels of a range of coated steels. The angle of panel, electrolyte flow rate and wet/dry cycles affect the runoff levels of such tests. The corrosion mechanisms of a variety of zinc-coated steels have been examined using the scanning vibrating electrode technique (SVET) in 0.1%NaCl. The corrosion behaviour of a coating is related to its structure and composition. The SVET has been used to assess total zinc loss from coatings during corrosion and has been confirmed using ICP-MS analysis. The predicted zinc losses from the SVET were used to model up to 12 months external weathering behaviour for the zinc-coated steels.
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Hesselbrandt, Max. "Luktreducering av stekos med absorptionsteknik." Thesis, KTH, Energiteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-170890.
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In exhaust and supply air ventilation with heat recovery, heat and moisture is transferred by a heat exchanger from the warm exhaust air flow to the cold supply air flow. Rotary regenerators are widely used due to their high efficiency, but have the drewback of transferring odourants from the kitchen hood exhaust air to the supply air. This causes odour problems that must be prevented. In this study, odour control by absorption has been studied theoretically in order to investigate whether it is possible to efficiently remove odorants from the kitchen hood exhaust air and minimizing heat losses simultaneously during the absorption process. By studying the olfactory system, some physicochemical properties of odorant molecules were identified. Furthermore, the mechanisms of mass and heat transfer were considered in order to identify the factors that affect the rate of mass and heat fluxes between the liquid and gas phases. Also, the main factors involving the design of packed columns were investigated. The study showed that there are several similarities between mass and heat transfer. Thus, some of the factors that were found to increase the rate of mass transfer also tend to cause an increase of heat transfer. Therefore, it is concluded that other options than absorption should be considered.I FTX-system återvinns värme och fukt i den varma inomhusluften och överförs i en värmeväxlare till den kalla uteluften. För detta syfte används vanligen den roterande regenerativa värmeväxlaren på grund av dess höga temperaturverkningsgrad, men nackdelen med denna typ av värmeväxlare är att luktämnen från köksventilationen kan överföras till den inkommande tilluften. Detta orsakar luktproblem och måste förhindras. Syftet med denna studie är att undersöka huruvida absorption kan användas för att effektivt rena spiskåpans frånluft från luktämnen och andra föroreningar samtidigt som eventuella värmeförluster minimeras. Genom att studera luktsinnets funktion har de fysiokemiska egenskaper som är karaktäristiska för luktämnen kartlagts. Vidare har mekanismerna bakom mass- och värmeöverföring tagits i betraktande i syfte att identifiera de faktorer som påverkar graden av mass- och värmeflöden mellan gas- och vätskefas. Studien innefattar även den tekniska utformningen av en packad kolonn. Studien visar att det finns en tydlig analogi mellan mass- och värmeöverföring. Detta innebär att några av de faktorer som bidrar till en högre grad av massöverföring också tenderar att öka graden av värmeöverföring. Således kan en slutsats dras om att absorption som metod inte är optimal i detta avseende, varför andra lösningar bör övervägas.