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Pork tenderness estimation by taste panel, Warner-Bratzler shear force and on-line methods.  

UK PubMed Central (United Kingdom)

The extent to which modification of Warner-Bratzler shear force (WBSF) determinations, relating to storage and preparation of the meat, aperture of the V-shaped cutting blade and shearing velocity, improve the relationship with sensory tenderness perception of pork was studied. Additionally four on-line methods: pH1, FOP1 (light scattering), PQM1 (conductivity) and DDLT (Double Density Light Transmission), were evaluated for their ability to predict tenderness. Sensory tenderness evaluation was conducted on 120 frozen (at -18 degrees C for several months) samples of m. longissimus thoracis et lumborum. After overnight thawing, the meat was grilled to an internal temperature of 74 degrees C and scored on an eight-point scale, from extremely tough to extremely tender. The standard WBSF procedure (protocol A) consisted of heating fresh meat samples (stored for 48 h at 4 degrees C post slaughter) at 75 degrees C for 50 min, cooling in cold tap water for 40 min, taking cylindrical cores parallel to the fibre direction, and shearing at a velocity of 200 mm/min with a blade aperture of 60 degrees. For the prediction of sensory tenderness, the WBSF standard procedure (protocol A) showed the lowest variance (R2=15%) and the highest standard error of the estimate (SEE=0.97 N) compared to the other WBSF protocols. A decrease in shearing velocity, from 200 to 100 mm/min and, a replacement of the cutting blade with an aperture of 60 degrees by one with an aperture of 30 degrees led to improvements of R2 (respectively, 19% vs. 13% and 47% vs. 23%) and SEE (respectively, 0.93 N vs. 0.97 N and 0.80 N vs. 0.97 N) and thus were better predictors of tenderness. A blade aperture of 30 degrees instead of 60 degrees also led to considerably lower WBSF values (22.1 N vs. 30.0 N). Freezing, frozen storage and thawing of the meat, prior to WBSF measurement, resulted in higher shear force values (32.7 N vs. 28.7 N) and a better prediction of tenderness, R2 (25% vs. 15%) and SEE (0.94 N vs. 1.00 N). Furthermore, preparing the frozen stored meat for WBSF determination in the same way as for the sensory evaluation, namely grilling instead of boiling, led to higher WBSF values (35.5 N vs. 32.7 N) and a further improvement in the prediction of tenderness (R2=31% vs. 25% and SEE=0.90 N vs. 0.94 N). From the on-line instruments: pH, FOP and PQM, pH was best in predicting tenderness. Linear regression with tenderness as dependent variable and the on-line techniques as independent variables revealed the following R2: 16, 8, 8 and 10% and SEE: 0.96, 1.01, 1.01 and 1.00 N for, respectively, pH1, FOP1, PQM1 and DDLT. Thus, the classical instruments and the DDLT technique, which is analogous to the CGM (Capteur Gras/Maigre), an officially accepted carcass grading apparatus in France and Belgium, are not good predictors of tenderness.

Oeckel MJvan; Warnants N; Boucque CV

1999-12-01

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Pork tenderness estimation by taste panel, Warner-Bratzler shear force and on-line methods.  

UK PubMed Central (United Kingdom)

The extent to which modification of Warner-Bratzler shear force (WBSF) determinations, relating to storage and preparation of the meat, aperture of the V-shaped cutting blade and shearing velocity, improve the relationship with sensory tenderness perception of pork was studied. Additionally four on-line methods: pH1, FOP1 (light scattering), PQM1 (conductivity) and DDLT (Double Density Light Transmission), were evaluated for their ability to predict tenderness. Sensory tenderness evaluation was conducted on 120 frozen (at -18°C for several months) samples of m. longissimus thoracis et lumborum. After overnight thawing, the meat was grilled to an internal temperature of 74°C and scored on an eight-point scale, from extremely tough to extremely tender. The standard WBSF procedure (protocol A) consisted of heating fresh meat samples (stored for 48 h at 4°C post slaughter) at 75°C for 50 min, cooling in cold tap water for 40 min, taking cylindrical cores parallel to the fibre direction, and shearing at a velocity of 200 mm/min with a blade aperture of 60°. For the prediction of sensory tenderness, the WBSF standard procedure (protocol A) showed the lowest variance (R(2)=15%) and the highest standard error of the estimate (SEE=0.97 N) compared to the other WBSF protocols. A decrease in shearing velocity, from 200 to 100 mm/min and, a replacement of the cutting blade with an aperture of 60° by one with an aperture of 30° led to improvements of R(2) (respectively, 19% vs. 13% and 47% vs. 23%) and SEE (respectively, 0.93 N vs. 0.97 N and 0.80 N vs. 0.97 N) and thus were better predictors of tenderness. A blade aperture of 30° instead of 60° also led to considerably lower WBSF values (22.1 N vs. 30.0 N). Freezing, frozen storage and thawing of the meat, prior to WBSF measurement, resulted in higher shear force values (32.7 N vs. 28.7 N) and a better prediction of tenderness, R(2) (25% vs. 15%) and SEE (0.94 N vs. 1.00 N). Furthermore, preparing the frozen stored meat for WBSF determination in the same way as for the sensory evaluation, namely grilling instead of boiling, led to higher WBSF values (35.5 N vs. 32.7 N) and a further improvement in the prediction of tenderness (R(2)=31% vs. 25% and SEE=0.90 N vs. 0.94 N). From the on-line instruments: pH, FOP and PQM, pH was best in predicting tenderness. Linear regression with tenderness as dependent variable and the on-line techniques as independent variables revealed the following R(2): 16, 8, 8 and 10% and SEE: 0.96, 1.01, 1.01 and 1.00 N for, respectively, pH1, FOP1, PQM1 and DDLT. Thus, the classical instruments and the DDLT technique, which is analogous to the CGM (Capteur Gras/Maigre), an officially accepted carcass grading apparatus in France and Belgium, are not good predictors of tenderness.

Van Oeckel MJ; Warnants N; Boucqué CV

1999-12-01

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Genome-wide association analysis for quantitative trait loci influencing Warner-Bratzler shear force in five taurine cattle breeds.  

UK PubMed Central (United Kingdom)

We performed a genome-wide association study for Warner-Bratzler shear force (WBSF), a measure of meat tenderness, by genotyping 3360 animals from five breeds with 54 790 BovineSNP50 and 96 putative single-nucleotide polymorphisms (SNPs) within ?-calpain [HUGO nomenclature calpain 1, (mu/I) large subunit; CAPN1] and calpastatin (CAST). Within- and across-breed analyses estimated SNP allele substitution effects (ASEs) by genomic best linear unbiased prediction (GBLUP) and variance components by restricted maximum likelihood under an animal model incorporating a genomic relationship matrix. GBLUP estimates of ASEs from the across-breed analysis were moderately correlated (0.31-0.66) with those from the individual within-breed analyses, indicating that prediction equations for molecular estimates of breeding value developed from across-breed analyses should be effective for genomic selection within breeds. We identified 79 genomic regions associated with WBSF in at least three breeds, but only eight were detected in all five breeds, suggesting that the within-breed analyses were underpowered, that different quantitative trait loci (QTL) underlie variation between breeds or that the BovineSNP50 SNP density is insufficient to detect common QTL among breeds. In the across-breed analysis, CAPN1 was followed by CAST as the most strongly associated WBSF QTL genome-wide, and associations with both were detected in all five breeds. We show that none of the four commercialized CAST and CAPN1 SNP diagnostics are causal for associations with WBSF, and we putatively fine-map the CAPN1 causal mutation to a 4581-bp region. We estimate that variation in CAST and CAPN1 explains 1.02 and 1.85% of the phenotypic variation in WBSF respectively.

McClure MC; Ramey HR; Rolf MM; McKay SD; Decker JE; Chapple RH; Kim JW; Taxis TM; Weaber RL; Schnabel RD; Taylor JF

2012-12-01

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Genome-wide association analysis for quantitative trait loci influencing Warner-Bratzler shear force in five taurine cattle breeds.  

Science.gov (United States)

We performed a genome-wide association study for Warner-Bratzler shear force (WBSF), a measure of meat tenderness, by genotyping 3360 animals from five breeds with 54 790 BovineSNP50 and 96 putative single-nucleotide polymorphisms (SNPs) within ?-calpain [HUGO nomenclature calpain 1, (mu/I) large subunit; CAPN1] and calpastatin (CAST). Within- and across-breed analyses estimated SNP allele substitution effects (ASEs) by genomic best linear unbiased prediction (GBLUP) and variance components by restricted maximum likelihood under an animal model incorporating a genomic relationship matrix. GBLUP estimates of ASEs from the across-breed analysis were moderately correlated (0.31-0.66) with those from the individual within-breed analyses, indicating that prediction equations for molecular estimates of breeding value developed from across-breed analyses should be effective for genomic selection within breeds. We identified 79 genomic regions associated with WBSF in at least three breeds, but only eight were detected in all five breeds, suggesting that the within-breed analyses were underpowered, that different quantitative trait loci (QTL) underlie variation between breeds or that the BovineSNP50 SNP density is insufficient to detect common QTL among breeds. In the across-breed analysis, CAPN1 was followed by CAST as the most strongly associated WBSF QTL genome-wide, and associations with both were detected in all five breeds. We show that none of the four commercialized CAST and CAPN1 SNP diagnostics are causal for associations with WBSF, and we putatively fine-map the CAPN1 causal mutation to a 4581-bp region. We estimate that variation in CAST and CAPN1 explains 1.02 and 1.85% of the phenotypic variation in WBSF respectively. PMID:22497286

McClure, M C; Ramey, H R; Rolf, M M; McKay, S D; Decker, J E; Chapple, R H; Kim, J W; Taxis, T M; Weaber, R L; Schnabel, R D; Taylor, J F

2012-02-27

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Ranking beef muscles for Warner-Bratzler shear force and trained sensory panel ratings from published literature  

UK PubMed Central (United Kingdom)

Meat scientists have long studied palatability traits of beef muscles, but few characterized numerous muscles over significant numbers of animals. The objective of this project was to rank the major beef muscles for Warner-Bratzler shear force (WBS) and sensory traits based on a comprehensive study of the literature, thereby compiling a large number of observations for each muscle. Muscles with three or more literature sources were ranked for WBS (n = 40), sensory tenderness (n = 14), juiciness (n = 13) and beef flavor (n = 9). Psoas major and infraspinatus were the top ranked for mechanical and sensory tenderness. Semitendinosus, gluteus medius, supraspinatus and pectoralis profundus were major muscles that were among the least tender. The Pearson correlation coefficient of WBS and sensory tenderness means was ?0.84 (P = 0.001). These rankings may be useful as a reference for relative palatability of muscles. Practical Applications: Knowledge of the relative palatability and rank of individual muscle can serve as a resource at the retail and foodservice establishment to better meet consumers' needs, and through use in educational materials. The popularity and demand of the flat iron (infraspinatus) and petite tender (teres major) steaks are examples of better utilizing and merchandizing the carcass. Furthermore, it can aid processors and product development specialists in identifying additional muscles suitable for value-added processing and possibilities for acceptable muscle substitutions. Utilization by academics will be through reference for research needs and classroom instruction. The results of this ranking can be utilized by all sectors of the meat industry to ultimately provide an improved product for the consumer.

Sullivan GA; Calkins CR

2011-06-01

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The interrelationship between sensory tenderness and shear force measured by the G2 Tenderometer and a Lloyd texture analyser fitted with a Warner-Bratzler head.  

UK PubMed Central (United Kingdom)

A comparison of peak shear force results for a Lloyd texture analyser fitted with a Warner Bratzler type of shearing head and a G2 Tenderometer was undertaken using sheep meat. The G2 is a new version of the Tenderometer that uses an electric linear motor to compress the sample, but still retains the blunt wedge-shaped "tooth". Analysis of sheep meat samples (n=121) revealed that the average G2 Tenderometer shear force results were approximately 1.2 times those for the Lloyd based on the following model; Lloyd=1.561 Tenderometer(0.84). Both instruments explained low amounts of the variation (less than 20%) in the sensory traits tenderness and overall liking. The high values for the sensory traits indicate that a wider range of samples, including samples with lower sensory scores, is required to develop robust threshold estimates so that either instrument could be use as an auditing instrument for the processing industry.

Hopkins DL; Lamb TA; Kerr MJ; van de Ven RJ

2013-04-01

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Effect of Dry-Air Chilling on Warner-Bratzler Shear Force and Water-Holding Capacity of Broiler Breast Meat Deboned Four Hours Postmortem  

Directory of Open Access Journals (Sweden)

Full Text Available Advantages of air chilling (AC) methods over immersion chilling (IC) methods in quality retention and improvement of deboned chicken breast meat depend on experimental conditions, such as deboning time. The objective of this study was to evaluate the effect of a dry-AC method on shear force and water-holding capacity (WHC) of broiler breast meat deboned 4h postmortem compared to hot-boned (no chill) or immersion-chilled meat. Ready-to-cook broiler carcasses were hot-boned, chilled by ice water immersion (0.3 °C, 50 min) or chilled by cross-flow cold, dry air (0.7 °C, 150 min). Pectoralis (p.) major and p. minor were removed from the bone at 4 h postmortem. Shear force was measured using a Warner-Bratzler (WB) method and WHC was estimated using cooking yield, drip loss, amount of bound water (filter paper method) and water uptake (swell/centrifugation method). Regardless of muscle type, the WB shear force value of AC samples was significantly lower than that of hot-boned samples; however, there was no difference in the shear force between AC and IC. Regardless of measurement methods, there were no differences (P > 0.05) in WHC between the three treatments. These results demonstrate that when compared to no chill, AC followed by 4 h postmortem deboning can lead to a difference in WB shear values while WHC properties can be retained. For broiler breast meat deboned 4 h postmortem, AC does not result in any significant differences in shear force and WHC when compared to IC.

H. Zhuang; E.M. Savage; D.P. Smith; M.E. Berrang

2008-01-01

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Study of the Warner-Bratzler Shear Force, Sensory Analysis and Sarcomere Length as Indicators of the Tenderness of Sun-Dried Beef  

Directory of Open Access Journals (Sweden)

Full Text Available Sun-dried beef is a frequently consumed and valued product in Brazil, however, there have been no scientific studies on its texture. To assess the tenderness of sun-dried beef, an instrumental analysis (Warner-Bratzler Shear Force; WBSF), a sensory analysis (Quantitative Descriptive Analysis; QDA) and the sarcomere length (SL) were used as indicators. Significant differences were observed among the sun-dried beef samples. Sample 3 (composed of sun-dried meat purchased at three fairs from Region 3 in the city of João Pessoa-PB) was considered the most tender by the assessors, with a score of 6.7, and its WBSF analysis revealed a maximum value of 2.70 kgf. Additionally, this sample exhibited the highest SL value (1.89 µm). Samples 1 and 2 (composed of sun-dried meat purchased at three fairs from Regions 1 and 2, respectively, in the city of João Pessoa) exhibited very similar tenderness values (WBSF and QDA) but differed in their SL values, which suggested that sample 2 was the least tender. In conclusion, these results demonstrate that the studied parameters are complementary and can be used as tenderness indicators for sun-dried beef. However, although the difference was beyond the detection limit of the assessors and the texturometer, the SL analysis appears to have been the most effective.

Yuri Ishihara; Ricardo Moreira; Geany de Souza; Alanne Salviano; Marta Madruga

2013-01-01

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Study of the Warner-Bratzler shear force, sensory analysis and sarcomere length as indicators of the tenderness of sun-dried beef.  

UK PubMed Central (United Kingdom)

Sun-dried beef is a frequently consumed and valued product in Brazil, however, there have been no scientific studies on its texture. To assess the tenderness of sun-dried beef, an instrumental analysis (Warner-Bratzler Shear Force; WBSF), a sensory analysis (Quantitative Descriptive Analysis; QDA) and the sarcomere length (SL) were used as indicators. Significant differences were observed among the sun-dried beef samples. Sample 3 (composed of sun-dried meat purchased at three fairs from Region 3 in the city of João Pessoa-PB) was considered the most tender by the assessors, with a score of 6.7, and its WBSF analysis revealed a maximum value of 2.70 kgf. Additionally, this sample exhibited the highest SL value (1.89 µm). Samples 1 and 2 (composed of sun-dried meat purchased at three fairs from Regions 1 and 2, respectively, in the city of João Pessoa) exhibited very similar tenderness values (WBSF and QDA) but differed in their SL values, which suggested that sample 2 was the least tender. In conclusion, these results demonstrate that the studied parameters are complementary and can be used as tenderness indicators for sun-dried beef. However, although the difference was beyond the detection limit of the assessors and the texturometer, the SL analysis appears to have been the most effective.

Ishihara Y; Moreira R; de Souza G; Salviano A; Madruga M

2013-01-01

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Study of the Warner-Bratzler shear force, sensory analysis and sarcomere length as indicators of the tenderness of sun-dried beef.  

Science.gov (United States)

Sun-dried beef is a frequently consumed and valued product in Brazil, however, there have been no scientific studies on its texture. To assess the tenderness of sun-dried beef, an instrumental analysis (Warner-Bratzler Shear Force; WBSF), a sensory analysis (Quantitative Descriptive Analysis; QDA) and the sarcomere length (SL) were used as indicators. Significant differences were observed among the sun-dried beef samples. Sample 3 (composed of sun-dried meat purchased at three fairs from Region 3 in the city of João Pessoa-PB) was considered the most tender by the assessors, with a score of 6.7, and its WBSF analysis revealed a maximum value of 2.70 kgf. Additionally, this sample exhibited the highest SL value (1.89 µm). Samples 1 and 2 (composed of sun-dried meat purchased at three fairs from Regions 1 and 2, respectively, in the city of João Pessoa) exhibited very similar tenderness values (WBSF and QDA) but differed in their SL values, which suggested that sample 2 was the least tender. In conclusion, these results demonstrate that the studied parameters are complementary and can be used as tenderness indicators for sun-dried beef. However, although the difference was beyond the detection limit of the assessors and the texturometer, the SL analysis appears to have been the most effective. PMID:23966070

Ishihara, Yuri; Moreira, Ricardo; de Souza, Geany; Salviano, Alanne; Madruga, Marta

2013-08-07

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National Beef Tenderness Survey-2010: Warner-Bratzler shear force values and sensory panel ratings for beef steaks from United States retail and food service establishments.  

UK PubMed Central (United Kingdom)

The tenderness and palatability of retail and food service beef steaks from across the United States (12 cities for retail, 5 cities for food service) were evaluated using Warner-Bratzler shear (WBS) and consumer sensory panels. Subprimal postfabrication storage or aging times at retail establishments averaged 20.5 d with a range of 1 to 358 d, whereas postfabrication times at the food service level revealed an average time of 28.1 d with a range of 9 to 67 d. Approximately 64% of retail steaks were labeled with a packer/processor or store brand. For retail, top blade had among the lowest (P < 0.05) WBS values, whereas steaks from the round had the greatest (P < 0.05) values. There were no differences (P > 0.05) in WBS values between moist-heat and dry-heat cookery methods for the top round and bottom round steaks or between enhanced (contained salt or phosphate solution) or nonenhanced steaks. Food service top loin and rib eye steaks had the lowest (P < 0.05) WBS values compared with top sirloin steaks. Retail top blade steaks and food service top loin steaks received among the greatest (P < 0.05) consumer sensory panel ratings compared with the other steaks evaluated. Prime food service rib eye steaks received the greatest ratings (P < 0.05) for overall like, like tenderness, tenderness level, like juiciness, and juiciness level, whereas ungraded rib eye steaks received the lowest ratings (P < 0.05) for like tenderness and tenderness level. The WBS values for food service steaks were greater (P < 0.05) for the Select and ungraded groups compared with the Prime, Top Choice, and Low Choice groups. The WBS values and sensory ratings were comparable to the last survey, signifying that no recent or substantive changes in tenderness have occurred.

Guelker MR; Haneklaus AN; Brooks JC; Carr CC; Delmore RJ Jr; Griffin DB; Hale DS; Harris KB; Mafi GG; Johnson DD; Lorenzen CL; Maddock RJ; Martin JN; Miller RK; Raines CR; VanOverbeke DL; Vedral LL; Wasser BE; Savell JW

2013-02-01

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Beef longissimus lumborum, biceps femoris, and deep pectoralis Warner-Bratzler shear force is affected differently by endpoint temperature, cooking method, and USDA quality grade.  

UK PubMed Central (United Kingdom)

Effects of endpoint temperature, cooking method, and quality grade on Warner-Bratzler shear force (WBSF) of beef longissimus lumborum (LL), biceps femoris (BF), and deep pectoralis (DP) muscles were evaluated. Eighteen of all three subprimals were selected from USDA Select and 18 from USDA Choice (Certified Angus Beef) carcasses for the respective muscles. Muscles were vacuum packaged and held at 1 °C for 14 days, frozen (-29 °C), sawed into 2.54-cm thick steaks, vacuum packaged, and stored frozen until cooking. Thawed steaks were cooked by either a Magikitch'n(®) electric belt-grill (BG) at 93 °C, or a water-bath at 93 °C, to one of nine endpoint temperatures: 40, 45, 50, 55, 60, 65, 70, 75, or 80 °C. Belt-grill cooking was much faster and resulted in distinctly less cooking loss than water-bath cooking. Water-bath cooking resulted in higher (P<0.0001) Instron(®) WBSF (31.92 N) than BG (28.25 N) for LL. The combination of Select quality grade and higher endpoint temperatures resulted in higher (P<0.05) WBSF for LL. Two distinct phases of tenderization/toughening occurred for BF. Between 40 and 60 °C, WBSF decreased from 43.95 to 38.16 N (P<0.01), whereas between 60 and 70 °C, WBSF increased from 38.16 N to 44.44 N (P<0.05). Water-bath cooling resulted in higher (P=0.0001) DP WBSF (71.12 N) than BG (59.25 N). The DP had a distinct (P<0.0001) decline in WBSF between 45 and 65 °C, irrespective of the cooking method, followed by an increase between 65 and 80 °C (P<0.01).

Obuz E; Dikeman ME; Grobbel JP; Stephens JW; Loughin TM

2004-10-01

13

National Beef Tenderness Survey-2010: Warner-Bratzler shear force values and sensory panel ratings for beef steaks from United States retail and food service establishments.  

Science.gov (United States)

The tenderness and palatability of retail and food service beef steaks from across the United States (12 cities for retail, 5 cities for food service) were evaluated using Warner-Bratzler shear (WBS) and consumer sensory panels. Subprimal postfabrication storage or aging times at retail establishments averaged 20.5 d with a range of 1 to 358 d, whereas postfabrication times at the food service level revealed an average time of 28.1 d with a range of 9 to 67 d. Approximately 64% of retail steaks were labeled with a packer/processor or store brand. For retail, top blade had among the lowest (P 0.05) in WBS values between moist-heat and dry-heat cookery methods for the top round and bottom round steaks or between enhanced (contained salt or phosphate solution) or nonenhanced steaks. Food service top loin and rib eye steaks had the lowest (P < 0.05) WBS values compared with top sirloin steaks. Retail top blade steaks and food service top loin steaks received among the greatest (P < 0.05) consumer sensory panel ratings compared with the other steaks evaluated. Prime food service rib eye steaks received the greatest ratings (P < 0.05) for overall like, like tenderness, tenderness level, like juiciness, and juiciness level, whereas ungraded rib eye steaks received the lowest ratings (P < 0.05) for like tenderness and tenderness level. The WBS values for food service steaks were greater (P < 0.05) for the Select and ungraded groups compared with the Prime, Top Choice, and Low Choice groups. The WBS values and sensory ratings were comparable to the last survey, signifying that no recent or substantive changes in tenderness have occurred. PMID:23230117

Guelker, M R; Haneklaus, A N; Brooks, J C; Carr, C C; Delmore, R J; Griffin, D B; Hale, D S; Harris, K B; Mafi, G G; Johnson, D D; Lorenzen, C L; Maddock, R J; Martin, J N; Miller, R K; Raines, C R; VanOverbeke, D L; Vedral, L L; Wasser, B E; Savell, J W

2012-12-10

14

Interrelationships among evaluations of beef longissimus and semitendinosus muscle tenderness by Warner-Bratzler shear force, a descriptive-texture profile sensory panel, and a descriptive attribute sensory panel.  

UK PubMed Central (United Kingdom)

The objective of our study was to examine the interrelationships among Warner-Bratzler shear force (WBSF) determinations, evaluation by a highly trained descriptive-texture-profile (DTP) sensory panel, and evaluation by a trained descriptive attribute (DA) sensory panel as affected by muscle fiber orientation of samples and shear-blade type. Longissimus lumborum and semitendinosus muscles (n = 18 of each) were cut into 2.54-cm steaks, which were cooked to 71 degrees C. Cores were obtained with two methods (parallel to the muscle fiber orientation and perpendicular to the cut steak surface), used for WBSF determinations with the typical V-shaped blade and modified WBSF determinations with a flat blade, and presented to the DTP and DA sensory panels. The V-shaped blade resulted in 1.4 to 2.5 kg lower (P < .05) mean WBSF values than the flat blade for both muscles. Cores taken parallel to the longissimus muscle fiber orientation had .64 kg higher (P < .05) mean WBSF values than cores taken perpendicular to the cut steak surface. Both panels detected differences among carcass replications; however, a panelist x replication effect (P < .05) occurred for the DA panel. Both panels detected differences (P < .05) in muscle fiber orientation for attributes related to tenderness. Correlations between sensory panel scores and WBSF values were dependent on blade type and coring method. Blade type and coring method had greater effects on correlations between sensory scores and WBSF values for the DTP panel than for the DA panel. Correlations between scores by both sensory panels and WBSF values were comparable. The more highly trained DTP panelists were more consistent in their evaluations of texture attributes; however, they were more sensitive to muscle fiber orientation. Both panels were effective in detecting differences among carcass replications.

Otremba MM; Dikeman ME; Milliken GA; Stroda SL; Unruh JA; Chambers E 4th

1999-04-01

15

Comparison between Allo-Kramer and Warner-Bratzler devices to assess rabbit meat tenderness  

Directory of Open Access Journals (Sweden)

Full Text Available A study was conducted to compare Allo-Kramer (AK) and Warner-Bratzler (WB) devices to evaluate rabbit meat texture and to assess their correlations with sensory tenderness. Meat samples characterized by a wide range of tenderness were prepared by boning longissimus lumborum muscles from 90 carcasses at different post mortem times (1, 3, 24h). The right loin of each carcass was used for WB and AK tests, whereas the left loin to assess sensory tenderness and juiciness. The sensory test indicated a higher tenderness and juiciness of rabbit meat obtained from carcasses boned at 24h post mortem in comparison with 1 and 3h post mortem. Both AK and WB methods were able to detect these differences. The AK shear force as well as the WB shear force and area were significantly correlated to meat sensory tenderness (r=-0.58, -0.43 and -0.56, respectively; P<0.001) and juiciness, whereas no correlation was found between sensory tenderness and WB firmness. These results indicate that both WB and AK methods can be used to evaluate the rabbit meat tenderness and give similar levels of correlation with sensory scores. However, AK method is characterized by a sample preparation procedure easier to standardize and less time consuming than WB method.

M. Bianchi; M. Petracci; M. Pascual; C. Cavani

2010-01-01

16

Effect of cooking temperature and cooking time on Warner-Bratzler tenderness measurement and collagen content in rabbit meat.  

UK PubMed Central (United Kingdom)

The effects of cooking temperature (50-90 °C) and time (10-120 min) on Warner-Bratzler (WB) tenderness measurement of longissimus lumborum (LL) muscle in 70-day-old rabbits were investigated. Cooking losses, total collagen content and collagen solubility of LL muscle were measured in parallel. Increasing cooking temperature caused a four-phase effect on WB measurement. Stress and total energy were significantly increased between raw meat and cooked meat at 50 °C, then they dramatically decreased to a minimum observed at 60-65 °C, and increased again to reach a maximum at 80-90 °C. Cooking losses exhibited an 83% increase between 50 and 80 °C. At 80 °C, stress and total energy values remained constant after 20 and 40 min respectively. LL muscle collagen content was 16.4±2.3 mg/g of dried muscle. Collagen solubility at 77 °C for 1 h was high: 75.3±8.1%.

Combes S; Lepetit J; Darche B; Lebas F

2004-01-01

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Espessura da lâmina de cisalhamento na avaliação instrumental da textura da carne/ Shear blade thickness in the instrumental evaluation of meat texture  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A padronização da textura é um dos principais problemas relacionados à qualidade da carne bovina. Por isso, a avaliação objetiva da maciez, por métodos mecânicos, vem sendo estudada há muitos anos. Para que a avaliação instrumental da textura seja uma ferramenta efetiva nos estudos envolvendo a maciez da carne, é necessário minimizar as causas de variação envolvidas na análise. Atualmente, a força de cisalhamento Warner-Bratzler é o método mais amplamen (more) te empregado para essa finalidade. O protocolo padrão dessa técnica analítica preconiza a utilização de uma lâmina de cisalhamento de 1,016mm de espessura. Neste trabalho, foram comparados dados de textura de carne bovina obtidos com a lâmina de cisalhamento padrão Warner-Bratzler, de 1,016mm de espessura, e uma lâmina mais grossa, de 3,05mm de espessura. Após o abate, amostras de músculo Longissimus dorsi, semelhantes em relação aos teores de umidade, lipídeos e proteínas, foram submetidas a duas diferentes temperaturas de resfriamento, atingindo diferentes velocidades de queda de temperatura e, consequentemente, diferentes graus de contração do tecido muscular, o que foi confirmado pela determinação do comprimento dos sarcômeros. Os resultados demonstraram uma maior sensibilidade da lâmina padrão Warner-Bratzler na detecção de variações da textura da carne, em função da velocidade de resfriamento. Abstract in english Standardization of texture is one of the main problems related to beef quality. Because of that, objective evaluation of tenderness performed by mechanic methodologies has been studied for years. In order to count on instrumental texture evaluation as a valuable tool in meat tenderness studies, it is necessary to minimize the causes of variation that might be involved in the trial. Nowadays, Warner-Bratzler shear force is widely used for meat tenderness determination. The (more) standard protocol of this methodology establishes the utilization of shear blade 1.016mm tick. The aim of this study was to compare beef texture data provided by Warner-Bratzler standard shear blade, 1.016mm thick, with those provided by a thicker one, 3.05mm thick. After slaughtering, Longissimus dorsi muscle samples with similar contents of moisture, lipids and proteins were subjected to two different cooling temperatures,reaching different rates of temperature drop and hence different muscle contraction extents, which were confirmed by the determination of sarcomere length. Results indicated the superior sensibility of the Warner-Bratzler standard shear blade to detect variations in meat texture due to cooling velocity.

Pinto, Marcos Franke; Ponsano, Elisa Helena Giglio; Almeida, Ana Paula da Silva

2010-06-01

18

Espessura da lâmina de cisalhamento na avaliação instrumental da textura da carne Shear blade thickness in the instrumental evaluation of meat texture  

Directory of Open Access Journals (Sweden)

Full Text Available A padronização da textura é um dos principais problemas relacionados à qualidade da carne bovina. Por isso, a avaliação objetiva da maciez, por métodos mecânicos, vem sendo estudada há muitos anos. Para que a avaliação instrumental da textura seja uma ferramenta efetiva nos estudos envolvendo a maciez da carne, é necessário minimizar as causas de variação envolvidas na análise. Atualmente, a força de cisalhamento Warner-Bratzler é o método mais amplamente empregado para essa finalidade. O protocolo padrão dessa técnica analítica preconiza a utilização de uma lâmina de cisalhamento de 1,016mm de espessura. Neste trabalho, foram comparados dados de textura de carne bovina obtidos com a lâmina de cisalhamento padrão Warner-Bratzler, de 1,016mm de espessura, e uma lâmina mais grossa, de 3,05mm de espessura. Após o abate, amostras de músculo Longissimus dorsi, semelhantes em relação aos teores de umidade, lipídeos e proteínas, foram submetidas a duas diferentes temperaturas de resfriamento, atingindo diferentes velocidades de queda de temperatura e, consequentemente, diferentes graus de contração do tecido muscular, o que foi confirmado pela determinação do comprimento dos sarcômeros. Os resultados demonstraram uma maior sensibilidade da lâmina padrão Warner-Bratzler na detecção de variações da textura da carne, em função da velocidade de resfriamento.Standardization of texture is one of the main problems related to beef quality. Because of that, objective evaluation of tenderness performed by mechanic methodologies has been studied for years. In order to count on instrumental texture evaluation as a valuable tool in meat tenderness studies, it is necessary to minimize the causes of variation that might be involved in the trial. Nowadays, Warner-Bratzler shear force is widely used for meat tenderness determination. The standard protocol of this methodology establishes the utilization of shear blade 1.016mm tick. The aim of this study was to compare beef texture data provided by Warner-Bratzler standard shear blade, 1.016mm thick, with those provided by a thicker one, 3.05mm thick. After slaughtering, Longissimus dorsi muscle samples with similar contents of moisture, lipids and proteins were subjected to two different cooling temperatures,reaching different rates of temperature drop and hence different muscle contraction extents, which were confirmed by the determination of sarcomere length. Results indicated the superior sensibility of the Warner-Bratzler standard shear blade to detect variations in meat texture due to cooling velocity.

Marcos Franke Pinto; Elisa Helena Giglio Ponsano; Ana Paula da Silva Almeida

2010-01-01

19

Atributos de qualidade da carne de paca (Agouti paca): perfil sensorial e força de cisalhamento/ Quality attributes of paca meat (Agouti paca): sensory profile and shear force  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Avaliaram-se as características sensoriais e determinou-se a força de cisalhamento de cortes de carne de paca (Agouti paca). As análises foram realizadas nos cortes desossados de paleta, lombo e pernil de nove pacas, preparados por cocção até a temperatura interna de 70ºC. A avaliação de aspecto, cor, sabor, odor e maciez foi realizada pela aplicação de teste afetivo a 146 provadores, utilizando-se escala hedônica, e a força de cisalhamento foi determinada pe (more) la técnica Warner Bratzler. Na avaliação sensorial, os cortes de paleta, lombo e pernil de paca mostraram diferença significativa (p Abstract in english Sensory characteristics and shear force of paca meat (Agouti paca) were assessed in this study. Analyses were performed in the bonelessshoulder,loin andhamobtained from nine paca carcassesprepared by cookinguntil reaching the internal temperatureof 70°C. The evaluation of flavor, aroma, color, appearance and tenderness was carried out by the application of an affective test using the hedonic scaleand a 146 consumer panel. Shear force was determined by the Warner-Bratzler (more) technique. Shoulder, loin and ham had significant differences (p

Gomes, C.; Karam, L.B.; Macedo, R.E.F.

2013-04-01

20

Interviews with Infopros: Sarah Warner.  

Science.gov (United States)

Sarah Warner is manager of content licensing for Amulet, which provides an Internet-based automated research service in information technology (InfoWizard). In this interview, she discusses her work experience as a cataloger and information center manager, carry over skills from past positions, her present responsibilities in content management,…

Everett, Melissa

1997-01-01

 
 
 
 
21

Atributos de qualidade da carne de paca (Agouti paca): perfil sensorial e força de cisalhamento Quality attributes of paca meat (Agouti paca): sensory profile and shear force  

Directory of Open Access Journals (Sweden)

Full Text Available Avaliaram-se as características sensoriais e determinou-se a força de cisalhamento de cortes de carne de paca (Agouti paca). As análises foram realizadas nos cortes desossados de paleta, lombo e pernil de nove pacas, preparados por cocção até a temperatura interna de 70ºC. A avaliação de aspecto, cor, sabor, odor e maciez foi realizada pela aplicação de teste afetivo a 146 provadores, utilizando-se escala hedônica, e a força de cisalhamento foi determinada pela técnica Warner Bratzler. Na avaliação sensorial, os cortes de paleta, lombo e pernil de paca mostraram diferença significativa (p0,05) entre os cortes, que se mostraram igualmente macios. A carne de paca apresentou-se sensorialmente semelhante à carne suína e com boa aceitação pelos consumidores. O estudo evidenciou o potencial da paca como uma espécie silvestre para a produção comercial de carne para o mercado de carnes vermelhas ou exóticas.Sensory characteristics and shear force of paca meat (Agouti paca) were assessed in this study. Analyses were performed in the bonelessshoulder,loin andhamobtained from nine paca carcassesprepared by cookinguntil reaching the internal temperatureof 70°C. The evaluation of flavor, aroma, color, appearance and tenderness was carried out by the application of an affective test using the hedonic scaleand a 146 consumer panel. Shear force was determined by the Warner-Bratzler technique. Shoulder, loin and ham had significant differences (p 0.05) among the cuts, which were similarly tender. Paca meat was found to resemble pork meat in sensory evaluation and had good acceptance by consumers. This study showed the potential of paca (Agouti paca) asa wild species for meat production in the red or exotic meat market.

C. Gomes; L.B. Karam; R.E.F. Macedo

2013-01-01

22

Effect of prolonged heat treatments at low temperature on shear force and cooking loss in cows and young bulls.  

DEFF Research Database (Denmark)

Long term heat treatment at low temperature (LTLT) is known to decrease toughness of meat. However, the contribution from the connective tissue to the toughness of LTLT treated meat is not clear. The aim of the present study was to investigate the effect of LTLT treatments on shear force and cooking loss in semitendinosus from cows (4-6 years) and young bulls (12-14 months), representing 2 categories of beef with varying thermal strength of connective tissue. Vacuum packed muscle samples were heat treated at 53°C, 55°C, 58°C and 63°C in water baths for 2½, 7½ and 19½ h. Cooking loss and Warner-Bratzler shear force were measured after heat treatment and subsequent cooling. Shear force of semitendinosus from young bulls heated at 53°C for 2½ h was significantly higher compared with all other heat treatments. A decrease of app. 40 N was observed when increasing the heating temperature from 53°C to 55°C, or when increasing heating time from 2½ to 7½ h at 53°C. In semitendinosus from cows shear force decreased significantly with increasing temperature, and with increasing heating time from 2½ to 19½ h at 55°C and 63°C. Cooking loss increased with increasing heating temperature in both beef categories. The results show that prolonged heating at low temperatures reduce toughness in beef semitendinosus, and that a reduction in toughness require higher temperatures and longer heating times in semitendinosus from cows compared with young bulls.

Christensen, L.; Andersen, L.

2011-01-01

23

Lena Angevine Warner: pioneer public health nurse.  

UK PubMed Central (United Kingdom)

Lena Angevine Warner was a remarkable early southern nurse who, as a result of her Army experience with the Walter Reed Commission yellow fever experiments in Cuba, directed her life work to disease prevention and public health. This biographic sketch traces her long and productive career from 1889 until her retirement in 1946, and illustrates her significant contributions to public health nursing in the mid-South.

Greenhill ED

1994-06-01

24

AOL Time Warner Clears Final Hurdle  

Science.gov (United States)

America Online (AOL) and Time Warner received conditional approval from the Federal Communications Commission last night, clearing the way for the creation of the world's largest media company and the third-largest merger in history. As a condition for the merger's approval, the FCC added some restrictions to those already stipulated by other oversight panels. The FCC beefed up requirements that the new company share its cable pipeline with competing Internet service providers, required that future broadband versions of AOL's instant messaging service work with competitors, and forced a complete severance of all links with AT&T's cable service. Reaction by consumer groups has been mixed. Some have cautiously welcomed the cable line sharing requirements as an opportunity to increase consumer choice. Others have expressed continued concern over the sheer size and market power of a company that will now control both content and conduit.

De Nie, Michael W.

25

Evaluation of slice shear force as an objective method of assessing beef longissimus tenderness.  

UK PubMed Central (United Kingdom)

Experiments were conducted to develop an optimal protocol for measurement of slice shear force (SSF) and to evaluate SSF as an objective method of assessing beef longissimus tenderness. Whereas six cylindrical, 1.27-cm-diameter cores are typically removed from each steak for Warner-Bratzler shear force (WBSF) determination, a single 1-cm-thick, 5-cm-long slice is removed from the lateral end of each longissimus steak for SSF. For either technique, samples are removed parallel to the muscle fiber orientation and sheared across the fibers. Whereas WBSF uses a V-shaped blade, SSF uses a flat blade with the same thickness (1.016 mm) and degree of bevel (half-round) on the shearing edge. In Exp. 1, longissimus steaks were acquired from 60 beef carcasses to determine the effects of belt grill cooking rate (very rapid vs. rapid) and conditions of SSF measurement (hot vs cold) on the relationship of SSF with trained sensory panel (TSP) tenderness rating. Slice shear force was more strongly correlated with TSP tenderness rating when SSF measurement was conducted immediately after cooking (r = -.74 to -.76) than when steaks were chilled (24 h, 4 degrees C) before SSF measurement (r = -.57 to -.72). When SSF measurement was conducted immediately after cooking, the relationship of SSF with TSP tenderness rating did not differ among the belt grill cooking protocols used to cook the SSF steak. In Exp. 2, longissimus steaks were acquired from 479 beef carcasses to compare the ability of SSF and WBSF of 1.27-cm-diameter cores to predict TSP tenderness ratings. Slice shear force was more strongly correlated with sensory panel tenderness rating than was WBSF (r = -.82 vs -.77). In Exp. 3, longissimus steaks were acquired from 110 beef carcasses to evaluate the repeatability (.91) of SSF over a broad range of tenderness. Slice shear force is a more rapid, more accurate, and technically less difficult technique than WBSF. Use of the SSF technique could facilitate the collection of more accurate data and should allow the detection of treatment differences with reduced numbers of observations and reduced time requirements, thereby reducing research costs.

Shackelford SD; Wheeler TL; Koohmaraie M

1999-10-01

26

Mineral Resources of the South Warner Contiguous Wilderness Study Area, Modoc County, California.  

Science.gov (United States)

The South Warner Contiguous Wilderness Study Area (CA-020-708) is located along the east flank of the South Warner Mountains in northwestern California. At the request of the U.S. Bureau of Land Management, 4,330 acres of the South Warner Contiguous Wilde...

M. G. Sawlan J. G. Frisken M. S. Miller

1989-01-01

27

Evaluation of sampling, cookery, and shear force protocols for objective evaluation of lamb longissimus tenderness.  

UK PubMed Central (United Kingdom)

Experiments were conducted to compare the effects of two cookery methods, two shear force procedures, and sampling location within non-callipyge and callipyge lamb LM on the magnitude, variance, and repeatability of LM shear force data. In Exp. 1, 15 non-callipyge and 15 callipyge carcasses were sampled, and Warner-Bratzler shear force (WBSF) was determined for both sides of each carcass at three locations along the length (anterior to posterior) of the LM, whereas slice shear force (SSF) was determined for both sides of each carcass at only one location. For approximately half the carcasses within each genotype, LM chops were cooked for a constant amount of time using a belt grill, and chops of the remaining carcasses were cooked to a constant endpoint temperature using open-hearth electric broilers. Regardless of cooking method and sampling location, repeatability estimates were at least 0.8 for LM WBSF and SSF. For WBSF, repeatability estimates were slightly higher at the anterior location (0.93 to 0.98) than the posterior location (0.88 to 0.90). The difference in repeatability between locations was probably a function of a greater level of variation in shear force at the anterior location. For callipyge LM, WBSF was higher (P < 0.001) at the anterior location than at the middle or posterior locations. For non-callipyge LM, WBSF was lower (P < 0.001) at the anterior location than at the middle or posterior locations. Consequently, the difference in WBSF between callipyge and non-callipyge LM was largest at the anterior location. Experiment 2 was conducted to obtain an estimate of the repeatability of SSF for lamb LM chops cooked with the belt grill using a larger number of animals (n = 87). In Exp. 2, LM chops were obtained from matching locations of both sides of 44 non-callipyge and 43 callipyge carcasses. Chops were cooked with a belt grill and SSF was measured, and repeatability was estimated to be 0.95. Repeatable estimates of lamb LM tenderness can be achieved either by cooking to a constant endpoint temperature with electric broilers or cooking for a constant amount of time with a belt grill. Likewise, repeatable estimates of lamb LM tenderness can be achieved with WBSF or SSF. However, use of belt grill cookery and the SSF technique could decrease time requirements which would decrease research costs.

Shackelford SD; Wheeler TL; Koohmaraie M

2004-03-01

28

A Case Study: Translation Problems in the Story of Rustam and Sohrab Based on Warner & Warner Translation  

Directory of Open Access Journals (Sweden)

Full Text Available Throughout the history, translation has played an important role in conveying thoughts and knowledge from one nation to other nations. Apart from this importance, the act of translating is not simply changing a message from the source language into the target one; translation is an act of problem–solving. Sometimes it is difficult to solve problems existing in translation, and so the notion of untranslatability emerges. Regarding the text–types, this problem is more prominent in the translation of literary texts like poems. This study attempts to investigate untranslatable elements in a poem, and for this purpose it concentrates on the story of Rustam & Sohrab selected from Shahnameh by Firdowsi and its equivalent translation by Warner & Warner. Then it focuses on the relation of untranslatablility in the story of Rustam & Sohrab with the semantic translation of Warner & Warner and the style of Firdowsi. Further research is required in this direction to answer questions concerning the notion of untranslatability and other related matters like the purpose of translation and untranslatability.

Habibollah Mashhady; Mahbube Noura

2012-01-01

29

Interview with a quality leader: Dale W. Bratzler, DO, MPH on performance measures. Interview by Jason Trevor Fogg.  

UK PubMed Central (United Kingdom)

Dale Bratzler, DO, MPH, currently serves as the President and CEO of the Oklahoma Foundation for Medical Quality (OFMQ). In addition, he provides support as the Medical Director of the Patient Safety Quality Improvement Organization Support Center at OFMQ. In these roles, he provides clinical and technical support for local and national hospital quality improvement initiatives. He is a Past President of the American Health Quality Association and a recent member of the National Advisory Council for the Agency for Healthcare Research and Quality. Dr. Bratzler has published extensively and frequently presents locally and nationally on topics related to healthcare quality, particularly associated with improving care for pneumonia, increasing vaccination rates, and reducing surgical complications. He received his Doctor of Osteopathic Medicine degree at the Kansas City University of Medicine and Biosciences, and his Master of Public Health degree from the University of Oklahoma Health Sciences Center College of Public Health. Dr. Bratzler is board certified in internal medicine.

Bratzler DW

2010-03-01

30

Draft Recovery Plan for the Threatened and Rare Native Fishes of the Warner Basin and Alkali Subbasin: Warner sucker (Threatened) 'Catostomus warnerensis', Hutton tui chub (Threatened) 'gila bicolor ssp.', Fkoskett speckled dace (Threatened) 'Rhinichthys osculus ssp.', Cowhead Lake tui chub (Candidate) 'Gila bicolor vaccaceps', Warner Valley redband trout, 'Oncorhynchus mykiss ssp.'.  

Science.gov (United States)

This recovery plan provides information to guide recovery of the threatened native fishes of the Warner Basin and the Alkali Subbasin in southeastern Oregon. This plan focuses on three species listed as threatened in 1985, the Warner sucker (Catostomus wa...

A. Bentivoglio R. White L. Smith

1997-01-01

31

Technical note: use of belt grill cookery and slice shear force for assessment of pork longissimus tenderness.  

UK PubMed Central (United Kingdom)

The present experiments were conducted to determine whether improved beef longissimus shear force methodology could be used to assess pork longissimus tenderness. Specifically, three experiments were conducted to: 1) determine the effect of belt grill (BG) cookery on repeatability of pork longissimus Warner-Bratzler shear force (WBSF), 2) compare the correlation of WBSF and slice shear force (SSF) with trained sensory panel tenderness ratings, and 3) estimate the repeatability of pork longissimus SSF for chops cooked with a BG. In Exp. 1 and 2, the longissimus was removed from the left side of each carcass (Exp. 1, n = 25; Exp. 2, n = 23) at 1 d postmortem and immediately frozen to maximize variation in tenderness. In Exp. 1, chops were cooked with either open-hearth electric broilers (OH) or BG, and WBSF was measured. Percentage of cooking loss was lower (P < 0.001) and less variable for chops cooked with a BG (23.2%; SD = 1.7%) vs. OH (27.6%; SD = 3.0%). Estimates of the repeatability of WBSF were similar for chops cooked with OH (0.61) and BG (0.59). Although significant (P < 0.05), differences in WBSF (4.1 vs. 3.9 kg) between cooking methods accounted for less than 5% of the total variation in WBSF. In Exp. 2, the correlation of SSF (r = -0.72; P < 0.001) with trained sensory panel tenderness ratings was slightly stronger than the correlation of WBSF (r = -0.66; P < 0.001) with trained sensory panel tenderness ratings, indicating that the two methods had a similar ability to predict tenderness ratings. In Exp. 3, duplicate samples from 372 carcasses at 2 and 10 d postmortem were obtained, cooked with BG, and SSF was determined. The repeatability of SSF was 0.90, which is comparable to repeatability estimates for beef and lamb. Use of BG cookery and SSF could facilitate the collection of accurate pork longissimus tenderness data. Time and labor savings associated with BG cookery and the SSF technique should help to decrease research costs.

Shackelford SD; Wheeler TL; Koohmaraie M

2004-01-01

32

Ecological investigation of a hazardous waste site, Warner Robins, Georgia  

Energy Technology Data Exchange (ETDEWEB)

Landfill No. 4 and the sludge lagoon at Robins Air Force Base, Warner Robins, Georgia, were added to the United States Environmental Protection Agency (EPA) National Priorities List in 1987 because of highpotential for contaminant migration. Warner Robins is located approximately 90 miles southeast of Atlanta. In 1990 CH2M HILL conducted a Remedial Investigation at the base that recommended that further ecological assessment investigations be conducted (CH2M HILL 1990). The subject paper is the result of this recommendation. The ecological study was carried out by the Hazardous Waste Remedial Actions Program (HAZWRAP)Division of Martin Marietta Energy Systems, Inc., working jointly with its subcontractor CDM (CDM 1992a). The primary area of investigation (Zone 1) included the sludge lagoon, Landfill No. 4, the wetland area east of the landfill and west of Hannah Road (including two sewage treatment ponds), and the area between Hannah Road and Horse Creek (Fig. 1). The bottomland forest wetlands of Zone 1 extend from the landfill east to Horse Creek. Surface water and groundwater flow across Zone 1 is generally in an easterly direction toward Horse Creek. Horse Creek is a south-flowing tributary of the Ocmulgee River Floodplain. The objective of the study was to perform a quantitative analysis of ecological risk associated with the ecosystems present in Zone 1. This investigation was unique because the assessment was to be based upon many measurement endpoints resulting in both location-specific data and data that would assess the condition of the overall ecosystem. The study was segregated into five distinct field investigations: hydrology, surface water and sediment, aquatic biology, wetlands ecology, and wildlife biology.

Wade, M. [Oak Ridge National Lab., TN (United States); Billig, P. [Camp Dresser and McKee, Inc., Denver, CO (United States)

1993-05-01

33

Sícorax e Serafine: a construção da comunidade no romance Índigo, de Marina Warner  

Directory of Open Access Journals (Sweden)

Full Text Available Durante os últimos quarenta anos, investigou-se e discutiu-se o aspecto pós-colonial da peça A tempestade, de Shakespeare. O romance Indigo, de Marina Warner, publicado em 1992, é a reescrita da peça, na qual os papéis femininos são realçados e analisados numa narrativa múltipla que compreende a invasão de uma ilha caribenha no século XVII e a fortuna dos descendentes desses invasores no século XX. Enquanto a ideologia dos colonizadores ingleses se baseava na construção de império, as duas personagens femininas, Sícorax e Serafine, se esforçam na construção de comunidades. Nessa versão feminina de A tempestade, Warner apresenta uma alternativa para suplantar o patriarcalismo e fundar princípios básicos para uma sociedade mais douradora e mais igualitáriaDuring the last four decades the postcoloniality in Shakespeare’s The Tempest has been investigated and discussed. Marina Warner’s novel Indigo, published in 1992, is a reworking of the play in which feminine roles are enhanced and analysed in a multiple narrative comprehending the 17th century invasion of a Caribbean island and the fortune of the invaders’ descendents in the 20th century. In contrast to the English colonizers stance of empire building, the two female characters of the novel, Sycorax and Serafine, endeavour to build communities. In this feminine version of The Tempest, Warner shows an alternative way to replace patriarchy and establish the basic tenets of a more-enduring and equalitarian society

Thomas Bonnici

2003-01-01

34

Relationship between calpastatin activity and lamb carcass characteristics.  

Science.gov (United States)

The purpose of this study was to determine if calpastatin activity (CALP) was related to the amount of intramuscular fat (IMF) and Warner-Bratzler shear force (WBS) in lamb carcasses. Market wethers representing three sire lines (n = 40, average live weight of 68.9 kg) were harvested at the OSU Mea...

35

Recovery Plan for the Threatened and Rare Native Fishes of the Warner Basin and Alkali Subbasin: Warner Sucker (Threatened ) 'Catostomus warnerensis', Hutton Tui Chub (Threatened) 'Gila bicolor' ssp., Foskett Speckled Dace (Threatened) 'Rhinichthys osculus' ssp.  

Science.gov (United States)

This recovery plan provides information to guide recovery of the threatened native fishes of the Warner Basin and the Alkai Subbasin in southeastern Oregon. This plan focuses on improving the aquatic ecosystem of three species listed as threatened in 1985...

1998-01-01

36

Gardening shears  

UK PubMed Central (United Kingdom)

A horticulture shear includes a first shear blade, whose front end is a shear part and rear end is a combination part, the combination part is arranged with a pivot hole and a shear blade connection hole the first shear blade is connected with a first grab handle a second shear blade, whose front end is a anvil part and rear end is a combination part, the combination part is arranged with a pivot hole, a shear connection hole and a handle rod connection hole a handle rod, which is pivoted in a second grab handle, one end of the handle rod is a combination part which is arranged with a pivot hole and a shear blade connection hole the two combination parts of the second shear blade and the grab handle overlap each other, the two combination parts of the first shear blade and the second shear blade overlap each other a pivot rotating element, which punctures the outer shell of the second grab handle and the pivot holes of the first shear blade, the second shear blade and the handle rod a shear blade connection bolt, which is pivoted in the shear connection holes of the first and second shear blade a shear blade pivot shaft, which is pivoted in the connection holes of the handle rod and the shear blades. By using the structure, the pivot point of the shear can#GB001t damage easily due to the extreme force, and the operation is labor saving.

SUHUA SHAN

37

Shear machines  

International Nuclear Information System (INIS)

[en] A shear machine for irradiated nuclear fuel elements has a replaceable shear assembly comprising a fuel element support block, a shear blade support and a clamp assembly which hold the fuel element to be sheared in contact with the support block. A first clamp member contacts the fuel element remote from the shear blade and a second clamp member contacts the fuel element adjacent the shear blade and is advanced towards the support block during shearing to compensate for any compression of the fuel element caused by the shear blade (U.K.)

1980-01-01

38

Walter Miles, Pop Warner, B. C. Graves, and the psychology of football.  

UK PubMed Central (United Kingdom)

In 1926-1927, a graduate student, B. C. Graves, working with Stanford University psychologist Walter Miles and legendary football coach Pop Warner, conducted an investigation of variations in signal calling as they affected the charging times of football players. The study was one of two that involved Miles and the ingenious multiple chronograph that he had invented to time the reactions of seven players simultaneously. These studies represented a brief digression in the career of Miles, who certainly was no sport psychologist. They tell of an interesting collaboration between scientist and coaches that produced one of the richest studies in sport psychology in the first half of the twentieth century.

Baugh FG; Benjamin LT Jr

39

Walter Miles, Pop Warner, B. C. Graves, and the psychology of football.  

Science.gov (United States)

In 1926-1927, a graduate student, B. C. Graves, working with Stanford University psychologist Walter Miles and legendary football coach Pop Warner, conducted an investigation of variations in signal calling as they affected the charging times of football players. The study was one of two that involved Miles and the ingenious multiple chronograph that he had invented to time the reactions of seven players simultaneously. These studies represented a brief digression in the career of Miles, who certainly was no sport psychologist. They tell of an interesting collaboration between scientist and coaches that produced one of the richest studies in sport psychology in the first half of the twentieth century. PMID:16345007

Baugh, Frank G; Benjamin, Ludy T

2006-01-01

40

On-line prediction of beef quality traits using near infrared spectroscopy.  

UK PubMed Central (United Kingdom)

The aim of this study was to test the ability of visible-near infrared (Vis-NIR) reflectance spectroscopy to predict beef quality traits in the slaughterhouse by directly applying a fiber-optic probe on the carcass surface. Carcasses from 230 young bulls and heifers slaughtered in two commercial abattoirs were included in the experiment. Vis-NIR spectra were recorded on an exposed surface of M. gracilis in the abattoirs 4 to 6 and 14 to 16 h post mortem. Traits evaluated were pH, color indexes (L*, a*, b*, H, and SI), cooking loss, and Warner-Bratzler shear force. Prediction models were satisfactory for pH and color indexes, and promising for cooking loss but not for Warner-Bratzler shear force. Results of this work show that Vis-NIR spectroscopy may be a useful tool for on-line prediction of some physical beef quality traits when applied directly on the carcass surface.

De Marchi M

2013-08-01

 
 
 
 
41

Industrial-hygiene survey report of Borg Warner Chemicals, Inc. , Woodmar Plant, Washington, West Virginia  

Energy Technology Data Exchange (ETDEWEB)

Due to possible worker exposure to 1,3-butadiene, a walk-through industrial-hygiene survey was conducted at Borg Warner Chemicals Woodmar Facility, Washington, West Virginia. The primary products of the facility are ABS plastics, polybutadiene latex and styrene butadiene rubber latex. In September 1981, a butadiene recovery system was added to the process vent streams. Of the total work force, 54 employees have potential for exposure to 1,3-butadiene. The mean 8-hour time-weighted average (TWA) of 23 personal samples collected during several periods in 1983 and 1985 was 4.5 parts per million (ppm). Analysis of a bulk sample showed traces of 1,3-butadiene, in the 0.04 to 0.2 nanograms/milligram range. The exposures to 1,3-butadiene were greater than 10ppm for two job classifications, control room and high heat operators. The company has accurate records on terminated and current employees. The author concludes that the facility is a candidate for inclusion in an in-depth industrial hygiene survey regarding 1,3-butadiene. Recommendations were given.

Roberts, D.

1986-08-01

42

No more Black and Blue: Women Against Violence Against Women and the Warner Communications boycott, 1976-1979.  

UK PubMed Central (United Kingdom)

In the mid-1970s, Women Against Violence Against Women (WAVAW), the first national feminist organization to protest mediated sexual violence against women, pressured the music industry to cease using images of violence against women in its advertising. This article presents a case study of WAVAW's national boycott of Warner Communications, Inc. and documents the activists' successful consumer campaign. The study reveals that media violence was central to feminist organizing efforts, and that WAVAW and related organizations helped establish a climate of concern about violence that motivated scientific research on the relationship between exposure to media violence and subsequent aggression.

Bronstein C

2008-04-01

43

Shear Strength  

Science.gov (United States)

Dr. John Atkinson, of the University of the West of England, developed a site for undergraduate students wanting to learn more about soil classification. His site addresses issues such as: shear strength, peak strength, and residual strength testing. Filled with charts, diagrams, statistics, the information is pertinent and easily understood by almost any audience.

Atkinson, John

2008-10-07

44

Effects of cooking method, reheating, holding time, and holding temperature on beef longissimus lumborum and biceps femoris tenderness.  

UK PubMed Central (United Kingdom)

Effects of cooking method, holding temperature, holding time, and reheating on Warner-Bratzler peak shear force (WBPSF); Warner-Bratzler myofibrillar force (WBM-F), Warner-Bratzler connective tissue force (WBC-F) and cooking loss were investigated. Two muscles (longissimus lumborum and biceps femoris) from USDA Choice beef carcasses were used. Water-bath cooking resulted in higher WBPSF, WBM-F, and WBC-F than belt-grill cooking for longissimus lumborum. The biceps femoris muscle tenderness improved more with holding time after cooking on a belt than the longissimus lumborum due to its higher collagen content. Cooking biceps femoris steaks to 54 degrees C by a belt grill and holding them at 57 C in a water bath for 15 min and subsequent reheating to 70 degrees C (best treatment combination) produced a 25% reduction in WBPSF, a 37% reduction in WBC-F, and a 12% reduction in WBM-F as compared to the control (cooking steaks directly to 70 degrees C without holding). Water-bath cooking resulted in lower WBPSF than belt-grill cooking for biceps femoris without any holding time, but further tenderization did not occur with holding. Water-bath cooking resulted in higher cooking losses than belt-grill cooking for both muscles.

Obuz E; Dikeman ME; Loughin TM

2003-10-01

45

Effects of cooking method, reheating, holding time, and holding temperature on beef longissimus lumborum and biceps femoris tenderness.  

Science.gov (United States)

Effects of cooking method, holding temperature, holding time, and reheating on Warner-Bratzler peak shear force (WBPSF); Warner-Bratzler myofibrillar force (WBM-F), Warner-Bratzler connective tissue force (WBC-F) and cooking loss were investigated. Two muscles (longissimus lumborum and biceps femoris) from USDA Choice beef carcasses were used. Water-bath cooking resulted in higher WBPSF, WBM-F, and WBC-F than belt-grill cooking for longissimus lumborum. The biceps femoris muscle tenderness improved more with holding time after cooking on a belt than the longissimus lumborum due to its higher collagen content. Cooking biceps femoris steaks to 54 °C by a belt grill and holding them at 57 °C in a water bath for 15 min and subsequent reheating to 70 °C (best treatment combination) produced a 25% reduction in WBPSF, a 37% reduction in WBC-F, and a 12% reduction in WBM-F as compared to the control (cooking steaks directly to 70 °C without holding). Water-bath cooking resulted in lower WBPSF than belt-grill cooking for biceps femoris without any holding time, but further tenderization did not occur with holding. Water-bath cooking resulted in higher cooking losses than belt-grill cooking for both muscles. PMID:22063447

Obuz, E; Dikeman, M E; Loughin, T M

2003-10-01

46

Shear machine with replaceable shear assembly  

Energy Technology Data Exchange (ETDEWEB)

A shear machine for irradiated nuclear fuel elements has a replaceable shear assembly comprising a fuel element support block, a shear blade support and two clamp members which hold the fuel element to be sheared in contact with the support block. A first clamp member contacts the fuel element remote from the shear blade and a second clamp member contacts the fuel element adjacent the shear blade and is advanced towards the support block during shearing to compensate for any compression of the fuel element caused by the shear blade.

Astill, M.; Sunderland, A.; Waine, M.G.

1981-01-20

47

Shear blade  

UK PubMed Central (United Kingdom)

An improved blade assembly for a tree harvester shear. The blade assembly comprises a horizontally oriented primary blade member which is narrow relative to its length, and a plurality of vertically oriented secondary blade members or splitter bars which are welded or otherwise fastened to the underside of the primary blade. The plural splitter bars, the narrow primary blade, and the open spaces formed behind the primary blade and between the splitter bars combine to reduce friction and relieve stresses in the cut log, resulting in significantly reduced butt end damage. The above construction also serves to provide a rigid blade assembly with little tendency to climb as it moves through a tree trunk. Accordingly, shear blade damage is minimized.

JASINSKI STANLEY C

48

Shear lag in shear/core walls  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Shear lag occurs not only in bridge decks and framed tubes, but also in shear/core walls. However, there have been relatively few studies on shear lag in wall structures. Moreover, most existing theories neglect shear lag in the webs and, although they are acceptable for bridge decks that normally h...

Kwan, AKH

49

Pruning-shears  

UK PubMed Central (United Kingdom)

A branch shear is provided, which comprises a mutually pivoted first shear component, a second shear component and an offsetting spring acted on the two shear components. The first shear component comprises a first shear blade and a first handle connected with the first shear blade the second shear component is composed of a second shear blade and a second handle connected with the second shear blade the two shear components are provided with a pivoting part at the connecting section between the shear blades and the handles. The shear is characterized in that: the pivoting part is provided with a spring containing space and the offsetting spring is arranged inside the spring containing space and also acts on the two shear components. The utility model features simple structure and convenient utilization and has highly stable and safe offsetting spring.

RENFU CHEN

50

HAND SHEARS  

UK PubMed Central (United Kingdom)

FIELD: agricultural engineering and horticulture. ^ SUBSTANCE: hand shears have cylindrical body incorporating piston, stepped stem, guiding bushing and return spring, knife with lever and counter knife, as well as cover positioned on top part of body and equipped with opening. Cylindrical protrusion formed on top part of body is arranged eccentrically with respect to body and stem and provided with thread. Counter knife is immovably fixed on cover having cylindrical portion equipped with internal thread by means of which thread cover is joined to eccentric protrusion of body. Guiding bushing is positioned within body between cover and spring. Diameter of stem mid portion exceeds diameter of bushing opening. ^ EFFECT: increased efficiency due to eccentricity of cylindrical protrusion allowing cutting force and size of knife pair aperture to be adjusted. ^ 2 cl, 4 dwg

GAPPOEV TATARKAN TUGANOVICH; TAVASIEV RAMAZAN MUSAEVICH; KOZAEV TAJMURAZ SADULOVICH; TSEBOEV EHDUARD ALIKHANOVICH

51

Relationship between commercially available DNA analysis and phenotypic observations on beef quality and tenderness.  

Science.gov (United States)

Warner-Bratzler shear force values from 560 mixed breed heifers and steers were used to determine estimates of genetic selection. Cattle were marketed from 2008 to 2011, and included five feedlot based research projects at the North Dakota State University-Carrington Research Extension Center. Samples were collected for IGENITY® analysis providing information that included selection indices and estimated breeding values for carcass traits. DNA-based test results were compared with actual carcass measurements. Marbling accounted for over 10% of the variation in WBSF while hot carcass weight was the second most influential carcass trait accounting for 4% (Pbeef tenderness and acceptability. PMID:23793083

Magolski, J D; Buchanan, D S; Maddock-Carlin, K R; Anderson, V L; Newman, D J; Berg, E P

2013-05-25

52

Use of near infrared spectroscopy for assessment of beef quality traits  

Directory of Open Access Journals (Sweden)

Full Text Available Chemical and physical traits and fatty acid composition of meat samples from 148 Piemontese beef samples were predicted by near infrared spectroscopy. Coefficients of determination in calibration (R2) ranged between 0.44 and 0.99 for chemical composition and between 0.02 and 0.98 for fatty acid (FA) profile, being in general more accurate for the major FA. The calibration results gave inaccurate prediction for cholesterol and collagen content and for most physical traits, such as Warner-Bratzler shear force, cooking loss, drip loss, colour (L, a, b) and pH.

M. De Marchi; P. Berzaghi; A. Boukha; M. Mirisola; L. Gallo

2010-01-01

53

Reduced shear power spectrum  

Energy Technology Data Exchange (ETDEWEB)

Measurements of ellipticities of background galaxies are sensitive to the reduced shear, the cosmic shear divided by (1-{kappa}) where {kappa} is the projected density field. They compute the difference between shear and reduced shear both analytically and with simulations. The difference becomes more important an smaller scales, and will impact cosmological parameter estimation from upcoming experiments. A simple recipe is presented to carry out the required correction.

Dodelson, Scott; /Fermilab /Chicago U., Astron. Astrophys. Ctr. /Northwestern U.; Shapiro, Charles; /Chicago U. /KICP, Chicago; White, Martin J.; /UC, Berkeley, Astron.

2005-08-01

54

Large branches pruning shears  

UK PubMed Central (United Kingdom)

The utility model relates to shears for pruning trees, in particular to shears for limbs. The shears comprise blades and handles, which are characterized in that the cutting face of one of the blades is equipped with a saw-tooth edge. One of the blades of the shears is equipped with saw teeth which are skid-proof and increase slipping resistance of limbs simultaneously, thereby achieving the purpose of skid prevention, and saving labor and time.

BEI HE

55

Force matching tree shear  

UK PubMed Central (United Kingdom)

A tree shear where the shear blade is moved by a power mechanism that includes a link and lever so arranged that the force available matches approximately, at all times, the force required to pass the shear blade through the tree to sever the same.

HAMILTON DOUGLAS D

56

Shearing type blowout preventer  

Energy Technology Data Exchange (ETDEWEB)

A ram-type shearing apparatus for a wellhead having a body with a vertical bore therethrough and aligned, opposed ram guideways extending outward in the body from the bore, a ram assembly in each of the guideways, each of the ram assemblies having a ram body with a shearing blade on the face of the ram and means for moving the ram inward and outward in the guideway, the cutting edge of the upper shear blade and the face of the ram assembly below the upper shear blade being concave to support the string during shearing sufficiently to constrain the string below the upper shear blade as it is sheared to a shape suitable for receiving an overshot type of retrieving tool and to allow flow therein, the lower shear blade having at least one node extending toward the upper shear blade so that when a pipe is being sheared the node engages and penetrates the pipe prior to other shearing of the pipe to thereby reduce the force used for such shearing.

Troxell Jr., J. N.

1985-08-27

57

Two Kazdan-Warner type identities for the renormalized volume coefficients and the Gauss-Bonnet curvatures of a Riemannian metric  

CERN Multimedia

In this note, we prove two Kazdan-Warner type identities involving $v^{(2k)}$, the renormalized volume coefficients of a Riemannian manifold $(M^n,g)$, and $G_{2r}$, the so-called Gauss-Bonnet curvature, and a conformal Killing vector field on $(M^n,g)$. In the case when the Riemannian manifold is locally conformally flat, $v^{(2k)}=(-2)^{-k}\\sigma_k$, $G_{2r}(g)=\\frac{4^r(n-r)!r!}{(n-2r)!}\\sigma_r$, and our results reduce to earlier ones established by Viaclovsky and by the second author.

Guo, Bin; Li, Haizhong

2009-01-01

58

Dipole shear anisotropy logging  

Energy Technology Data Exchange (ETDEWEB)

Sonic-scale shear anisotropy of formations are obtained from dipole-shear measurements acquired by orthogonal source and receiver pairs. These measurements resemble miniature 4-component shear VSP surveys inside the borehole. Data from two orthogonal sources and an array of orthogonal receivers are processed providing three main logs; the fast and slow shear slownesses, and the fast shear polarization angle. Potential applications include: shale anisotropy for better seismic models, maximum stress and fracture/microcrack strike direction for horizontal well drilling and fracture height and azimuth determination in hydraulic fracturing.

Esmersoy, C.; Kane, M. [Schlumberger-Doll Research, Ridgefield, CT (United States); Koster, K.; Williams, M. [Amoco Production, Denver, CO (United States); Boyd, A. [GeoQuest, Aurora, CO (United States)

1994-12-31

59

Clip type gardening shears  

UK PubMed Central (United Kingdom)

The utility model provides clip type garden shears which belong to the technical field of gardening tools, and comprise a shear body One and a shear body Two the front parts of the shear body One and the shear body Two are respectively a shear blade and an edge pushing blade, and the back parts thereof are respectively a handle One and a handle Two the shear blade takes the shape of a convex arc the edge pushing blade is matched with the shear blade and is bent in the same direction, thus taking the shape of a concave arc the back parts of the shear blade and the edge pushing blade are respectively provided with circular contact surfaces correspondingly the centers of the contact surfaces are respectively provided with a shaft hole in which a clip connecting the two shear bodies together is fixed and the edge of the shaft hole is provided with an opening in which a lubricating block is clamped. Compared with the prior art, the novel clip type garden shears are characterized by reasonable design, simple structure, convenient use and the like, can improve the work efficiency of the workers, and save time and effort.

YUNBING ZHOU

60

SHEAR GELS AND COMPOSITIONS COMPRISING SHEAR GELS  

UK PubMed Central (United Kingdom)

The present invention is directed to shear gels and topical compositions comprising the same. The topical compositions can be substantially free of silicone elastomers and yield excellent sensory characteristics when applied.

MOADDEL TEANOOSH; DOBKOWSKI BRIAN JOHN; WIS GABRIELA MARIA; PEHRATOVIC HASIBA

 
 
 
 
61

Shear Gels and Compositions Comprising Shear Gels  

UK PubMed Central (United Kingdom)

The present invention is directed to shear gels and topical compositions comprising the same. The topical compositions can be substantially free of silicone elastomers and yield excellent sensory characteristics when applied.

MOADDEL TEANOOSH; DOBKOWSKI BRIAN JOHN; WIS GABRIELA MARIA; PEHRATOVIC HASIBA

62

TURBULENT SHEAR ACCELERATION  

Energy Technology Data Exchange (ETDEWEB)

We consider particle acceleration by large-scale incompressible turbulence with a length scale larger than the particle mean free path. We derive an ensemble-averaged transport equation of energetic charged particles from an extended transport equation that contains the shear acceleration. The ensemble-averaged transport equation describes particle acceleration by incompressible turbulence (turbulent shear acceleration). We find that for Kolmogorov turbulence, the turbulent shear acceleration becomes important on small scales. Moreover, using Monte Carlo simulations, we confirm that the ensemble-averaged transport equation describes the turbulent shear acceleration.

Ohira, Yutaka, E-mail: ohira@phys.aoyama.ac.jp [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara 252-5258 (Japan)

2013-04-10

63

Idade e sexo na maciez da carne de ovinos da raça Corriedale Meat lamb tenderness influenced by age and sex in Corriedale lineage  

Directory of Open Access Journals (Sweden)

Full Text Available A maciez da carne geralmente é o atributo mais importante para o consumidor. Vários são os fatores que influem sobre esSe aspecto no animal, como por exemplo: genótipo, idade, sexo, entre outros. Neste estudo, verificou-se a influência da idade e do sexo na maciez do músculo Longissimus dorsi de ovinos da raça Corriedale, através de métodos sensoriais e instrumentais. Após o abate, realizou-se a avaliação visual da textura do músculo pela granulação da superfície do mesmo. As amostras foram congeladas por 5 meses. Após a cocção, foi analisada a maciez da carne pelo equipamento Warner-Bratzler shear medindo a força de cisalhamento, e por avaliação sensorial realizada por uma equipe treinada de julgadores. Resultados obtidos pela avaliação sensorial e instrumental indicaram que o músculo Longissimus dorsi de fêmeas e de animais de menor idade foram mais macios.The meat tenderness is the most important atribute to the consumer. Several factors have influence in this aspect, for exemple: genotype, age, sex and others. The objective of this work was to study the influence of age and sex on Longissimus dorsi muscle tenderness of Corriedale lineage lamb, through sensory and instrumental methods. After slaughter Longissimus dorsi, texture was evaluated by granite’s surface method. The samples were frozen for five months. After thawing and cooking, meat tenderness was evaluated by Warner-Bratzler shear and sensory evaluation by a group of trained judges. The results indicated that female and younger animals produced more tender meat.

Márcia Arocha Gularte; Rosa de Oliveira Treptow; Juvêncio Luís Fernandes Pouey; José Carlos Osório

2000-01-01

64

On-line prediction of beef quality traits using near infrared spectroscopy.  

Science.gov (United States)

The aim of this study was to test the ability of visible-near infrared (Vis-NIR) reflectance spectroscopy to predict beef quality traits in the slaughterhouse by directly applying a fiber-optic probe on the carcass surface. Carcasses from 230 young bulls and heifers slaughtered in two commercial abattoirs were included in the experiment. Vis-NIR spectra were recorded on an exposed surface of M. gracilis in the abattoirs 4 to 6 and 14 to 16 h post mortem. Traits evaluated were pH, color indexes (L*, a*, b*, H, and SI), cooking loss, and Warner-Bratzler shear force. Prediction models were satisfactory for pH and color indexes, and promising for cooking loss but not for Warner-Bratzler shear force. Results of this work show that Vis-NIR spectroscopy may be a useful tool for on-line prediction of some physical beef quality traits when applied directly on the carcass surface. PMID:23618741

De Marchi, Massimo

2013-03-16

65

Correlation and Categories of Meat Tenderness Based on Equipment and Panelist Test  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this study was to determine the correlation between Warner-Bratzler shear force (WBSF) and cooking loss with sensory local trained panelists rating on beef tenderness, also to determine WBSF range at each tenderness categories (extremely tender, tender, rather tender, rather tough, tough, and extremely tough). Meat from knuckles of Australian Beef Cross (ABX) steer were broiled until internal temperature 70, 80 and 90oC to get some WBSF values. Cooking loss was counted as percentages of meat weight losses during cooking. Each WBSF values and cooking loss data were correlated with panelists test scores used linier regression equation. Then, based on that linier regression were estimated WBSF range at each tenderness level. The result indicated that WBSF was positive correlated with panelists test that was indicated with determination coefficient 0.7668 (r2 = 0.7668). Cooking loss was strongly positive correlated with panelists rating tenderness (r2 = 0.8114). The result of meat tenderness range categories: extremely tender 0–3.30 kg/cm2, tender >3.30–5.00 kg/cm2, rather tender >5.00–6.71 kg/cm2, rather tough >6.71–8.42 kg/cm2, tough >8.42-10.12 kg/cm2, extremely tough >10.12 kg/cm2. (Animal Production 10(3): 188-193 (2008) Key Words: Meat tenderness, tenderness categories, panelist test, Warner-Bratzler shear, force, cooking loss

T Suryati; II Arief; BN Polii

2008-01-01

66

Impact of feeding various amounts of wet and dry distillers grains to yearling steers on palatability, fatty acid profile, and retail case life of longissimus muscle.  

UK PubMed Central (United Kingdom)

Due to increased production of ethanol, abundance of distillers grains (DG) is increasing. Steers (n = 176) were assigned to 1 of 5 treatment groups: steam-flaked corn (SFC), 10% dry DG (DDG), 10% wet DG (WDG), 20% WDG, or 30% WDG. The objectives were to determine the effects of feeding greater amounts of WDG, or DDG on meat quality. Steaks, 2.54 cm, were cut from strip loins and identified for simulated retail display, Warner-Bratzler shear force analysis, palatability, and fatty acid composition. Steaks from cattle fed 10% WDG and 30% WDG had smaller (P < 0.05) Warner-Bratzler shear force values than steaks from cattle fed 20% WDG. Trained sensory panelists found no differences (P > 0.05) in overall tenderness and off-flavors. No differences were found in total SFA and MUFA composition among treatments; however, 20% and 30% WDG had a greater proportion of PUFA and n-6 fatty acids than 10% WDG. No differences were found during simulated retail display between various amounts of WDG. Further research needs to be conducted to evaluate methods that aid in increasing shelf life of steaks from cattle fed greater rates of WDG.

Kinman LA; Hilton GG; Richards CJ; Morgan JB; Krehbiel CR; Hicks RB; Dillwith JW; Vanoverbeke DL

2011-01-01

67

Garden shears capable of increasing the shearing area  

UK PubMed Central (United Kingdom)

The utility model discloses garden shears capable of increasing the shearing area, which essentially comprise two handles and two shear blades which are articulated, wherein, each handle is provided with two teeth each shear blade is provided with a tooth one tooth of the handles is respectively meshed with the teeth of the shear blades and the other teeth of the handles are meshed together the transmission of the meshed teeth, the garden shears can increase the shearing area, and shear different branches and leaves.

YOUTANG LIN

68

Shear assembly for tree harvester  

UK PubMed Central (United Kingdom)

A shear assembly suitable for use with a tree harvesting machine including a shear support frame, a pair of blade arm assemblies, each carrying a shear blade, a hydraulic motor connected between the shear frame and each of the blade arm assemblies for opening and closing the shear assembly, and hydraulic lines leading to the hydraulic motors routed internally within the shear assembly to protect the hydraulic lines from possible damage.

OLDENBURG DORRANCE

69

Tree shear blade structure  

UK PubMed Central (United Kingdom)

Bolts detachably mount a thin tree-shearing blade on a peripheral reinforcing blade carrier swingably mounted on a tractor. The plunger of a hydraulic jack is connected directly to the blade, independently of the blade carrier, for swinging the blade to shear a tree. The force applied by the jack to the blade is applied in the plane of the blade. To prevent excess stress from being applied to the bolts connecting the blade and the blade carrier as a tree is sheared, the blade carrier includes projecting backing plates fitted against opposite edges of the blade for transmitting force applied to the blade directly to the blade carrier.

NILSEN CHRISTOPHER

70

Shearing Stress Meter.  

Science.gov (United States)

An improved shearing stress meter (drag plate) of 6 ft (183 cm) diameter has been constructed for micrometeorological work. This size should enable representative sampling of rough surfaces and is intended particularly for farmland experimental sites wher...

R. A. Lynch E. F. Bradley

1974-01-01

71

Dual shear blade assembly  

UK PubMed Central (United Kingdom)

A dual shear blade assembly for cutting through an article, includes a frame having an outwardly opening article receiving slot, a primary shear blade pivotally mounted on the frame and movable between an open position outwardly adjacent one side of the slot to a closed position across a substantial portion of the slot, a secondary shear blade pivotally mounted on the frame and movable between an open position outwardly adjacent the opposite side of the slot to a closed position across a relatively small portion of the slot, and a motor arrangement pivotally connected to the frame for swinging the primary and secondary shear blades in the same rotational direction respectively from their open positions in an opposite endward direction towards their closed positions and so constructed and arranged as to cleanly sever an article disposed in the slot with disproportionate opposite forces in order to assure that the article is positively biased toward a fully retained position within the slot.

WIRT LEON A

72

Soil and rock shear tester  

Energy Technology Data Exchange (ETDEWEB)

A device for determining the shear strength of rock and soil is disclosed. The device includes means for supporting the device within a borehole, a primary shaft, a plurality of shearing units slidably attached to the shaft having shear heads which are movable from a retracted position to a material-engaging expanded position, and a slip joint between adjacent shearing units such that the units operate independently from one another. The shearing units apply progressively greater normal forces on the material to be tested and sequentially shear the material being tested. In operation, the device is lowered into a borehole. Then the shearing units are moved from their retracted position to their expanded material-engaging position so as to apply progressively greater normal forces on the material to be tested. An axial force is then applied to the shaft so that the material engaged by the shearing unit closest to the anchor shears. After the material shears, the respective heads of the shearing unit are retracted and the axial force is transferred to the next adjacent shearing unit by means of the slip joint. After the material engaged by each of the shearing units is successively sheared, the shearing characteristics of the material may be determined from the known applied normal and shear forces.

Lutenegger, A. J.

1985-09-10

73

Ultrasonic shear wave couplant  

Energy Technology Data Exchange (ETDEWEB)

Ultrasonically testing of an article at high temperatures is accomplished by the use of a compact layer of a dry ceramic powder as a couplant in a method which involves providing an ultrasonic transducer as a probe capable of transmitting shear waves, coupling the probe to the article through a thin compact layer of a dry ceramic powder, propagating a shear wave from the probe through the ceramic powder and into the article to develop echo signals, and analyzing the echo signals to determine at least one physical characteristic of the article.

Kupperman, David S. (Oak Park, IL); Lanham, Ronald N. (Lockport, IL)

1985-01-01

74

Using deformed critters to determine angular shear and shear strain  

Science.gov (United States)

This activity provides a step by step example to help students figure out how to determine the angular shear and shear strain, using fossils with bilateral symmetry. Students first complete the work on an idealized critter, and then on a sheared trilobite using simple graphical techniques and basic trigonometry.

Moore, Angela

75

Shear stress measurements  

International Nuclear Information System (INIS)

[en] The design, calibration technique and calibration results are described of a special shear-stress probe of the Stanton type developed for aerodynamic experiments on a rod bundle. The results of the calibration are compared with Preston tube calibration curves. The calibration curves obtained are valid within the range Re=8x104 to 7x105. (F.M.)

1975-03-25

76

Shear banding in polymer solutions  

Science.gov (United States)

The current theoretical belief is that the steady-state shear banding in viscoelastic liquids requires a non-monotonic constitutive relationship between shear stress and shear rate. Although existing rheological studies conclude that the constitutive equation for entangled polymers is monotonic, recent experimental evidence suggests shear banding can nevertheless occur in polymer solutions. In this work, we predict, for the first time, steady state shear banding with a realistic monotonic constitutive theory for polymeric liquids. The key is that a proper account must be taken of the coupling of polymer stress to polymer concentration. We also predict multiple steady states at some shear rates as seen experimentally, with shear banding if the flow is ramped quickly enough from rest, but homogeneous linear shear flow otherwise.

Cromer, Michael; Villet, Michael C.; Fredrickson, Glenn H.; Leal, L. Gary

2013-05-01

77

Blowout preventer, shear ram, shear blade and seal therefor  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a blowout preventer having a pipe passage with guideways extending laterally from opposite sides of the pipe passage, and rams mounted in the guideways with opposed shear blades extending from the rams for movement between a spaced apart position to receive pipe in the pipe passage to an engaged position for shearing the pipe without crushing it and for sealing off the pipe passage. Each ram has a face with a central cutout portion for receiving the uncrushed sheared pipe. The improvement described here comprises: the opposed shear blades having generally flat upper and lower parallel surfaces with front, back and longitudinal side surfaces extending between the upper and lower parallel surfaces, the front surface forming a shear surface on the opposed shear blades; the shear surface on each of the opposed shear blades including guide surfaces extending toward the back surface and coveraging inwardly from the side surfaces. The guide surfaces terminate at their inner ends in an arcuate portion and the arcuate portion has an annular tapered cutting surface that extends on a diagonal plane between the upper and lower surfaces; and seal means on the opposed shear blades shaped to telescopically receive and sealingly engage the side and shear surfaces of the opposed blades when the rams are engaged to seal off the pipe passage when the pipe has been sheared.

Van Wickle, D.W.

1987-03-03

78

Relationships between sensory and physicochemical measurements in meat of rabbit from three different breeding systems using canonical correlation analysis.  

Science.gov (United States)

Meat from rabbits reared either according to a standard (STAND) or a high quality norm (LABEL) or a low growth breeding (RUSSE) system were submitted to a sensory evaluation and to a large set of physicochemical measurements (weight of retail cuts, colour parameters, ultimate pH, femur flexure test, Warner-Bratzler shear test, water holding capacities and cooking losses). STAND rabbit meat exhibited the most juicy meat in back and in leg (pLABEL>RUSSE. Canonical correlation analysis showed strong correlations between physicochemical and sensory variables (R(2)=0.73 and 0.68 between the two first pairs of canonical variates). Especially, sensory tenderness and WB shear test variables assessed on raw longissimus muscle (LL) were correlated. Fibrous attribute in back was correlated with cooking loss in LL. When analysed separately only RUSSE rabbits exhibited the same relations between variables as those calculated in whole dataset. PMID:22063605

Combes, Sylvie; González, Ignacio; Déjean, Sébastien; Baccini, Alain; Jehl, Nathalie; Juin, Hervé; Cauquil, Laurent; Gabinaud, Béatrice; Lebas, François; Larzul, Catherine

2008-04-10

79

Gelation under shear  

Energy Technology Data Exchange (ETDEWEB)

An experimental small angle neutron scattering (SANS) study of dense silica gels, prepared from suspensions of 24 nm colloidal silica particles at several volume fractions {theta} is discussed. Provided that {theta}{approx_lt}0.18, the scattered intensity at small wave vectors q increases as the gelation proceeds, and the structure factor S(q, t {yields} {infinity}) of the gel exhibits apparent power law behavior. Power law behavior is also observed, even for samples with {theta}>0.18, when the gel is formed under an applied shear. Shear also enhances the diffraction maximum corresponding to the inter-particle contact distance of the gel. Difficulties encountered when trying to interpret SANS data from these dense systems are outlined. Results of computer simulations intended to mimic gel formation, including computations of S(q, t), are discussed. Comments on a method to extract a fractal dimension characterizing the gel are included.

Butler, B.D.; Hanley, H.J.M.; Straty, G.C. [National Institute of Standards and Technology, Boulder, CO (United States); Muzny, C.D. [Univ. of Colorado, Boulder, CO (United States)

1995-12-31

80

Structural and Hydrologic Implications of Joint Orientations in the Warner Creek and Stony Clove Drainage Basins, Catskill Mountains, Eastern New York  

Science.gov (United States)

To investigate joint control on hydrology as well as tectonic implications, we conducted a study of joint orientations near the Stony Clove and Warner Creek drainages of the Catskill Mountains, Eastern New York. Specific goals of this research were to determine joint control on stream orientations and groundwater flow, to compare results with previous studies in the area, and to investigate their tectonic significance. Trails, streams, and road cuts were traversed to locate bedrock outcrops whose positions were determined using topographic maps and a handheld GPS unit. Additional outcrops were located using aerial photographs and GIS data. Joint orientations were measured using a standard Brunton pocket transit. The data was analyzed using Orient (Vollmer, 2010), an orientation analysis program, to plot joint and stream orientations on rose diagrams. ArcGIS was used to produce topographic, hill-shade, and stream drainage maps. Over 500 joint orientations at over 100 outcrop stations were collected. The data were plotted on a rose diagrams, and two major joint sets were found, one with a mean strike of 021° and one with a mean strike of 096°. Stream orientations were also plotted on a rose diagram showing an axial mean of 022°, and indicate that the joint set with mean strike of 021 may have a significant control on stream orientations. The hill-shade maps also demonstrate clearly the strong control of jointing on the topography. The data collected in this research expands on previous joint orientation studies of Engelder and Geiser (1980) in the southwestern and central Catskills, and is similar to joint orientations found by Isachsen et al. (1977) in their study of the Panther Mountain circular structure, a possible impact-related feature. The origin of this jointing is thought to be related to Alleghanian (Permian) and possibly Acadian (Devonian) orogenic events.

Haskins, M. N.; Vollmer, F. W.; Rayburn, J. A.; Gurdak, J. J.

2010-12-01

 
 
 
 
81

Cooking and palatability traits of beef longissimus steaks cooked with a belt grill or an open hearth electric broiler.  

UK PubMed Central (United Kingdom)

The objective of this experiment was to compare the effects of belt grill and Open Hearth electric broiler cookery on palatability and cooking traits of longissimus steaks. The longissimus thoracis from carcasses of grain-fed steers or heifers was used. Duplicate measurements were made for Warner-Bratzler shear force at 3 and at 14 d after slaughter (n = 180) and trained sensory evaluation at 14 d after slaughter (n = 91) using both cooking methods. Belt grill-cooked samples had lower (P<.01) percentage of cooking losses (21.5 vs 25.8%) and higher (P<.01) shear force values (4.6 vs 4.3 kg) than electric broiler-cooked samples. Repeatability of duplicate measurements was higher for cooking losses (.58 vs .23) and shear force values (.85 vs .64) for belt grill than for electric broiler cooked samples. Belt grilled steaks had lower (P<.01) cooking losses (20.2 vs 29.8%); higher (P<.01) tenderness (7.0 vs 6.7) and juiciness (6.0 vs 5.1); and lower (P<.02) connective tissue amount (7.7 vs 7.8), beef flavor intensity (5.0 vs 5.1), and off-flavor (3.2 vs 3.3) ratings than steaks cooked with the electric broiler. Belt grill cooking increased the repeatability of duplicate sensory measurements for tenderness (.87 vs .71), connective tissue amount (.66 vs .30), and juiciness (.51 vs .08) ratings, and cooking losses (.63 vs .18) compared with cooking with the electric broiler. Belt grill cooking increased the precision for measurements of cooking, Warner-Bratzler shear force, and palatability traits of beef longissimus thoracis.

Wheeler TL; Shackelford SD; Koohmaraie M

1998-11-01

82

Field Observations of Shear Waves  

Science.gov (United States)

Meanders of the mean alongshore current in the surf zone called shear waves have alongshore propagating velocity fluctuations with periods of a few minutes and alongshore wavelengths of a few hundred meters. Shear wave velocity fluctuations observed within 250 m of the shoreline of a sandy, barred beach for 4 months were approximately horizontally isotropic, with root-mean-square values between 10--40% of the mean alongshore current V. Cross-shore variations of the time-averaged, shear wave momentum flux were consistent with shear wave energy generation in locations where V and the cross-shore shear of the mean alongshore current Vx were high. Farther from the shoreline where V and Vx were weaker, shear wave energy was both dissipated and transfered to the mean flow. In case examples where V is a narrow jet near the shoreline, the observed strong decay of shear wave energy levels seawards of the jet, and the cross- and alongshore structure of shear waves within the jet, were similar to predictions based on the linearly unstable modes of the observed V. Observed shear wave energy levels also were high with a strong, but broad (e.g. weakly sheared) V that is only marginally linearly unstable. This research was supported by the Office of Naval Research and the National Ocean Partnership Program.

Guza, R. T.; Noyes, T. J.; Elgar, S.; Herbers, T. C.

2002-12-01

83

Power saving gardening holding shears  

UK PubMed Central (United Kingdom)

A labor saving horticulture gripping shear includes a first shear blade, whose combination part is arranged with a pivot hole and a shear blade connection hole the first shear blade is connected with the a first grab handle a second shear blade, whose combination part is arranged with a shear connection hole a handle rod, which is pivoted in a second grab handle, one end of the handle rod is a combination part a labor saving transmission component includes a gear block fixed on the lateral side of the handle combination part, a gear hole arranged at the combination part of the second shear blade the gear hole is sleeved on the gear block, the teeth part of the gear block and the gear hole are meshed by partial teeth the first shear blade is overlapped on the combination part of the second shear blade through the combination part a pivot rotating element, which punctures the pivot hole and is positioned between the gear hole and the gear block a shear blade connection bolt, which is pivoted in the connection hole. The utility model realizes the labor saving effect by the structure.

SUHUA SHAN

84

Functionality of the plastron in adults of Neochetina eichhorniae Warner (Coleoptera, Curculionidae): aspects of the integument coating and submersion laboratory experiments/ Funcionalidade do plastrão em adultos de Neochetina eichhorniae Warner (Coleoptera, Curculionidae): aspectos do revestimento tegumentar e experimentos laboratoriais de submersão  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A teoria plastrão foi testada em adultos de Neochetina eichhorniae Warner, 1970, por meio da análise da estrutura que reveste o tegumento destes insetos e em experimentos laboratoriais de submersão. Os processos tegumentares foram reconhecidos em três tipos: escamas aglutinadas e com perfurações largas; escamas plumosas de tamanhos e formas variadas; e pêlos. Os experimentos realizados com 264 indivíduos adultos os quais permaneciam submersos por diferentes interv (more) alos de tempo (n = 11) e em dois tratamentos, água natural não aerada e água previamente fervida, com quatro repetições para cada tratamento, revelaram uma mortalidade máxima após 24 horas de mergulho no tratamento água previamente fervida. A sobrevivência dos adultos foi negativa e significativamente correlacionada com os tratamentos empregados e entre os diferentes intervalos de tempo. Os valores de oxigênio dissolvido (mg/l) na água diferiram significativamente entre os tratamentos aplicados, sendo positivamente correlacionado com a sobrevivência dos adultos nos dois tratamentos, embora mais acentuadamente no tratamento com água previamente fervida. A mortalidade dos adultos após 24 horas de mergulho no tratamento com água previamente fervida pode estar associada às condições físico-químicas da água não testadas neste estudo, como, por exemplo, baixa tensão superficial e concentração de solutos. Estes resultados sugerem uma funcionalidade do plastrão nos adultos desta espécie. Abstract in english The plastron theory was tested in adults of Neochetina eichhorniae Warner, 1970, through the analysis of the structure that coats these insects' integument and also through submersion laboratorial experiments. The tegument processes were recognized in three types: agglutinated scales with large perforations, plumose scales of varied sizes and shapes, and hairs. The experiments were carried out on 264 adult individuals which were kept submerged at different time intervals (more) (n = 11) and in two types of treatment, natural non-aerated water and previously boiled water, with four repetitions for each treatment. The tests showed a maximum mortality after 24 hours of immersion in the previously boiled water treatment. The survival of the adults was negative and significantly correlated with the types of treatment employed and within the different time intervals. The values of oxygen dissolved in water (mg/l) differed significantly within the types of treatment employed. They were positively correlated with the survival of the adults in the two types of treatment, although more markedly in the treatment with previously boiled water. The mortality of adults after 24 hours of submersion in the treatment with previously boiled water may be associated with the physical-chemical conditions of the non-tested water in this study, such as low surface tension and concentration of solutes. These results suggest plastron functionality in the adults of this species.

Sousa, Wesley Oliveira de; Rosado-Neto, Germano Henrique; Marques, Marinêz Isaac

2012-09-01

85

Shear induced transformation in enstatite  

Energy Technology Data Exchange (ETDEWEB)

Shear-induced proto to clino transformation in enstatite is studied using a novel shear-compression experiment. The transformation can be critically induced by shear stress at 96 MPa which is independent of stress state, but sensitive to microstructure. Considerable non-linear stress vs strain behavior is observed in the shear compression test, where the {open_quotes}plasticity{close_quotes} results from transformation and depends on either microstructure or mechanical testing conditions. XRD on fracture surfaces confirms that transformation is induced by shear stress, and indicates that the amount of clinoenstatite produced is a function of stress state. Thus, the more compressive the stress, the higher the ultimate shear stress and the more the amount of transformed clinoenstatite.

Zhu, D.; Kriven, W.M. [Univ. of Illinois, Urbana-Champaign, IL (United States)

1996-12-31

86

Shear viscosity of nuclear matter  

CERN Document Server

In this talk I report my recent study on the shear viscosity of neutron-rich nuclear matter from a relaxation time approach. An isospin- and momentum-dependent interaction is used in the study. Effects of density, temperature, and isospin asymmetry of nuclear matter on its shear viscosity have been discussed. Similar to the symmetry energy, the symmetry shear viscosity is defined and its density and temperature dependence are studied.

Xu, Jun

2013-01-01

87

Direct Measurement of Turbulent Shear  

CERN Multimedia

A photon correlation method is introduced for measuring components of the shear rate tensor in a turbulent soap film. This new scheme, which is also applicable to three-dimensional flows, is shown to give the same results as Laser Doppler velocimetry, but with less statistical noise. The technique yields the mean shear rate s, its standard deviation, and a simple mathematical transform of the probability density function P(s) of the shear rate itself.

Stefanus, Stefanus; Goldburg, Walter

2010-01-01

88

Dislocation kinetics behind shear shocks  

Energy Technology Data Exchange (ETDEWEB)

High velocity oblique impact experiments result in both compression and shear shock waves. Behind the shear shock wave the particle velocity is transverse to the shock front. At large transverse particle velocities, dislocation kinetics can contribute a portion of the velocity. Based on a kinematic and thermodynamic model of dislocation kinetics, an analysis is made of the transverse strain and velocity behind a shear shock. Kinematics of dislocations in transverse motion behind the shock is formulated. A solution is given for an ideal case where the dislocation density function propagates as a pulse behind the shear shock. 9 refs.

Stout, R.B.; Anderson, G.D.

1985-06-01

89

Evaluation of electric belt grill, forced-air convection oven, and electric broiler cookery methods for beef tenderness research.  

UK PubMed Central (United Kingdom)

Five muscles from USDA Select beef carcasses were cooked on an electric belt grill at three temperatures (93, 117, and 163 degrees C), in a forced-air convection oven, and on an electric broiler to determine effects of cooking treatment and muscle on Warner-Bratzler shear force values, cooking traits (cooking loss, cooking time, and endpoint temperature), and repeatability of duplicate measurements. All cooking treatments allowed shear force differences to be detected (P<0.05) among the five muscles, although the differences were inconsistent. Neither longissimus lumborum nor semitendinosus shear values differed among the five cooking treatments; however, shear values for biceps femoris, deep pectoralis, and gluteus medius differed (P<0.05) among cooking treatments. Belt grill cooking resulted in the highest shear force repeatability (R = 0.70 to 0.89) for the longissimus lumborum. All cooking methods provided acceptable repeatability (R greater than or equal to 0.60) of shear values for the biceps femoris and semitendinosus. The electric broiler was the only cooking treatment that resulted in acceptable repeatability of shear force measurements for all five muscles. It is not recommended to use the gluteus medius to test treatment effects on shear force values. Belt grill or electric broiler cooking are recommended for shear force evaluations.

Lawrence TE; King DA; Obuz KE; Yancey EJ; Dikeman ME

2001-07-01

90

Evaluation of electric belt grill, forced-air convection oven, and electric broiler cookery methods for beef tenderness research.  

UK PubMed Central (United Kingdom)

Five muscles from USDA Select beef carcasses were cooked on an electric belt grill at three temperatures (93, 117, and 163°C), in a forced-air convection oven, and on an electric broiler to determine effects of cooking treatment and muscle on Warner-Bratzler shear force values, cooking traits (cooking loss, cooking time, and endpoint temperature), and repeatability of duplicate measurements. All cooking treatments allowed shear force differences to be detected (P<0.05) among the five muscles, although the differences were inconsistent. Neither longissimus lumborum nor semitendinosus shear values differed among the five cooking treatments; however, shear values for biceps femoris, deep pectoralis, and gluteus medius differed (P<0.05) among cooking treatments. Belt grill cooking resulted in the highest shear force repeatability (R=0.70 to 0.89) for the longissimus lumborum. All cooking methods provided acceptable repeatability (R?0.60) of shear values for the biceps femoris and semitendinosus. The electric broiler was the only cooking treatment that resulted in acceptable repeatability of shear force measurements for all five muscles. It is not recommended to use the gluteus medius to test treatment effects on shear force values. Belt grill or electric broiler cooking are recommended for shear force evaluations.

Lawrence TE; King DA; Obuz E; Yancey EJ; Dikeman ME

2001-07-01

91

Scaling of Entropic Shear Rigidity  

CERN Multimedia

The scaling of the shear modulus near the gelation/vulcanization transition is explored heuristically and analytically. It is found that in a dense melt the effective chains of the infinite cluster have sizes that scale sub-linearly with their contour length. Consequently, each contributes k_B T to the rigidity, which leads to a shear modulus exponent d\

Xing, X; Goldbart, P M

2004-01-01

92

BATTERY-POWERED PRUNING SHEARS  

UK PubMed Central (United Kingdom)

The invention relates to battery-powered pruning shears, in which a shear blade unit can be replaced in a simple manner after an actuator is actuated. In the operating state, the shear blade unit is held in a positive-locking manner in the housing as a result of engaging locating pins of a drive unit in locating holes of a stationary shear cutting blade and fixing said shear cutting blade in the housing in a positive-locking manner. Said drive unit can be raised by the actuator, preferably by a pivoting lever or also through a slide, a wedge gear, or a push-button, within the housing against spring force, whereby the positive lock is released and the blade unit is removed through a housing slit and can be replaced with another shear blade unit. In this process, the housing remains closed, and no installation measures are required, because after a new blade unit is inserted by returning the actuator designed as a lever, the drive unit, comprising an electric motor and gear unit, is transferred back into the operating position through spring force. In said operating position, the stationary shear blade is fixed in a positive-locking manner and the output element of the gear unit is inserted into the engagement part of the moving blade, whereby the shears are put into their operating state.

MOOG CHRISTOPHER

93

Shear Punching of Bridge Decks.  

Science.gov (United States)

The report summarizes the findings of the research on the susceptibility of reinforced concrete slabs of beam-slab type highway bridges to shear punch failure due to the wheel loads. The investigation included a review of literature on shear punching of b...

C. N. Kostem

1977-01-01

94

Shear dynamics of hydration layers.  

UK PubMed Central (United Kingdom)

Molecular dynamics (MD) simulations have been performed to investigate the shear dynamics of hydration layers of the thickness of D=0.61-2.44 nm confined between two mica surfaces. Emphases are placed on the external shear response and internal relaxation properties of aqueous films. For D=0.92-2.44 nm liquid phase, the shear responses are fluidic and similar to those observed in surface force balance experiments [U. Raviv and J. Klein, Science 297, 1540 (2002)]. However, for the bilayer ice (D=0.61 nm) [Y. S. Leng and P. T. Cummings, J. Chem. Phys. 124, 74711 (2006)] significant shear enhancement and shear thinning over a wide range of shear rates in MD regime are observed. The rotational relaxation time of water molecules in this bilayer ice is found to be as high as 0.017 ms (10(-5) s). Extrapolating the shear rate to the inverse of this longest relaxation time, we obtain a very high shear viscosity for the bilayer ice, which is also observed quite recently for D< or =0.6+/-0.3 nm hydration layers [H. Sakuma et al., Phys. Rev. Lett. 96, 46104 (2006)]. We further investigate the boundary slip of water molecules and hydrated K(+) ions and concluded that no-slip boundary condition should hold for aqueous salt solution under extreme confinement between hydrophilic mica surfaces, provided that the confined film is of Newtonian fluid.

Leng Y; Cummings PT

2006-09-01

95

Shear dynamics of hydration layers  

Science.gov (United States)

Molecular dynamics (MD) simulations have been performed to investigate the shear dynamics of hydration layers of the thickness of D=0.61-2.44 nm confined between two mica surfaces. Emphases are placed on the external shear response and internal relaxation properties of aqueous films. For D=0.92-2.44 nm liquid phase, the shear responses are fluidic and similar to those observed in surface force balance experiments [U. Raviv and J. Klein, Science 297, 1540 (2002)]. However, for the bilayer ice (D=0.61 nm) [Y. S. Leng and P. T. Cummings, J. Chem. Phys. 124, 74711 (2006)] significant shear enhancement and shear thinning over a wide range of shear rates in MD regime are observed. The rotational relaxation time of water molecules in this bilayer ice is found to be as high as 0.017 ms (10-5 s). Extrapolating the shear rate to the inverse of this longest relaxation time, we obtain a very high shear viscosity for the bilayer ice, which is also observed quite recently for D<=0.6+/-0.3 nm hydration layers [H. Sakuma et al., Phys. Rev. Lett. 96, 46104 (2006)]. We further investigate the boundary slip of water molecules and hydrated K+ ions and concluded that no-slip boundary condition should hold for aqueous salt solution under extreme confinement between hydrophilic mica surfaces, provided that the confined film is of Newtonian fluid.

Leng, Yongsheng; Cummings, Peter T.

2006-09-01

96

Direct measurement of turbulent shear  

Science.gov (United States)

A photon correlation method is introduced for measuring components of the shear rate tensor in a turbulent soap film. This new scheme, which is also applicable to three-dimensional flows, is shown to give the same results as laser Doppler velocimetry, but with less statistical noise. The technique yields the mean shear rate s¯, its standard deviation ?, and a simple mathematical transform of the probability density function P(s) of the shear rate itself. We propose a new method that can directly measure shear in 2 dimensional turbulence. This proposed method has better signal to noise ratio than the conventional method. It also yields information about the probability distribution of shear. The proposed method is inexpensive and applicable to 3 dimensional turbulence.

Stefanus, S.; Steers, S.; Goldburg, W. I.

2011-11-01

97

Electroosmotic shear flow in microchannels.  

Science.gov (United States)

We generate and study electroosmotic shear flow in microchannels. By chemically or electrically modifying the surface potential of the channel walls a shear flow component with controllable velocity gradient can be added to the electroosmotic flow caused by double layer effects at the channel walls. Chemical modification is obtained by treating the channel wall with a cationic polymer. In case of electric modification, we used gate electrodes embedded in the channel wall. By applying a voltage to the gate electrode, the zeta potential can be varied and a controllable, uniform shear stress can be applied to the liquid in the channel. The strength of the shear stress depends on both the gate voltage and the applied field which drives the electroosmotic shear flow. Although the stress range is still limited, such a microchannel device can be used in principle as an in situ micro-rheometer for lab on a chip purposes. PMID:23089595

Mampallil, Dileep; van den Ende, Dirk

2012-10-02

98

Electroosmotic shear flow in microchannels.  

UK PubMed Central (United Kingdom)

We generate and study electroosmotic shear flow in microchannels. By chemically or electrically modifying the surface potential of the channel walls a shear flow component with controllable velocity gradient can be added to the electroosmotic flow caused by double layer effects at the channel walls. Chemical modification is obtained by treating the channel wall with a cationic polymer. In case of electric modification, we used gate electrodes embedded in the channel wall. By applying a voltage to the gate electrode, the zeta potential can be varied and a controllable, uniform shear stress can be applied to the liquid in the channel. The strength of the shear stress depends on both the gate voltage and the applied field which drives the electroosmotic shear flow. Although the stress range is still limited, such a microchannel device can be used in principle as an in situ micro-rheometer for lab on a chip purposes.

Mampallil D; van den Ende D

2013-01-01

99

Pivot mechanism of gardener's shears  

UK PubMed Central (United Kingdom)

The utility model relates to a pivot mechanism of a pair of garden shears, which comprises a first shear blade, a second shear blade, two positioning covers, two movable covers two return springs, two lock plugs, and two lock screws, wherein the first shear blade and the second shear blade are eudipleural, both opposite and corresponding sides of a pivot part on the middle section of the utility model are respectively provided with a positioned pivot hole and a movable pivot hole which is arched and curved toward the inside lower part, the point inclined to one side of the lower part of the pivot part is penetrated with a clamping hole, the points of the inner surfaces of the positioning covers are concavely provided with a positioning slot, the outsides of the positioning covers are provided with a movable slot, both side points in the slot are respectively penetrated with another positioning pivot hole and another movable pivot hole, the inside of the lower part of the movable pivot hole is convexly and outward provided with a clamping block, the relative outside point of the clamping block is convexly provided with a linking block, one side of each of the movable covers are penetrated with the positioning pivot hole, the other side of the positioning pivot hole is penetrated with a movable through hole and the inside of the lower part is concavely provided with a movable pivot slot. The corresponding tangential force can not cause the damaged shear force which is generated between the first shear blade and the second shear blade to obstruct the branch gaps pruning when the first shear blade and the second shear blade are used.

HUANG YAOCHONG

100

Automatic heating warner for transfusion  

UK PubMed Central (United Kingdom)

The utility model relates to an automatic heating alarm device for transfusions, which belongs to the technical field of medical equipment manufacturing. The utility model is composed of three parts of an automatic heating circuit for liquid medicine, a liquid level testing circuit for liquid medicine, and a power circuit, wherein electrical connections are carried out among the circuits, and the automatic heating circuit for liquid medicine is composed of a thermometer, a thyristor, a diode, and a resistance wire electrical connections are carried out among the components of the automatic heating circuit for liquid medicine, and the thermometer is provided with electric contacts the resistance wire RL is formed to be a needle shape, and the surface of the resistance wire is coated with insulating materials with good heat-conducting properties the liquid level testing circuit for liquid medicine is composed of components of a photoelectric probe, a triode, a relay, a resistance, etc., and electrical connections are carried out among the components. The utility model has the advantages of low manufacturing cost, fast temperature rising speed, simpler and faster operation, high safety, recycle utilization, long service life, etc.

XUN ZHICAI

 
 
 
 
101

Wind shear detector  

Energy Technology Data Exchange (ETDEWEB)

A laser doppler velocimeter system for wind shear detection comprising means for generating a beam of radiant energy, an optical system coupled to the beam for directing a first portion of the beam a predetermined distance to a scatterer of radiant energy, means coupled to the beam for conducting a second portion of the beam through a polarization preserving medium, the length of the medium substantially matching the predetermined distance, means for mixing the second portion of the beam with the radiant energy reflected by the scatter and means coupled to the means for mixing for measuring a component of the velocity measurements of the scatter. The velocity includes both horizontal and vertical components. The system may also be adapted for measurement of multiple predetermined distances by using multiple means for conducting a second portion of the beam, each of said multiple means having a length substantially matching one of the multiple predetermined distances. The beam of radiant energy used may be an infrared laser. (author)

Rogers, P.L.; Rogers, M.

1991-02-07

102

Palatability of beef from bulls administered exogenous hormones.  

UK PubMed Central (United Kingdom)

One-hundred and forty four weanling bulls of Angus (A, n = 48), Simmental x Hereford (SH, n = 48) and Simmental (S, n = 48) breeding were either castrated, left intact, left intact and implanted with Ralgro or left intact and implanted with Synovex S. Cattle were slaughtered after either 190, 246 or 315 days of high-energy feeding, and the right side of each carcass was electrically stimulated. Sensory analysis was conducted on longissimus dorsi steaks after 5 days aging and Warner-Bratzler shear force (WBS) was measured after 5, 10 and 15 days aging. Steers had lower (P < 0·05) WBS and more desirable sensory panel scores for juiciness, ease of fragmentation, amount of connective tissue and overall tenderness than all intact treatments. The implanting of weanling bulls with synthetic steroid hormone compounds did not make a practical improvement in beef tenderness.

Shackelford SD; Savell JW; Crouse JD; Cross HR; Schanbacher BD; Johnson DD; Anderson ML

1992-01-01

103

Palatability of beef from bulls administered exogenous hormones.  

Science.gov (United States)

One-hundred and forty four weanling bulls of Angus (A, n = 48), Simmental x Hereford (SH, n = 48) and Simmental (S, n = 48) breeding were either castrated, left intact, left intact and implanted with Ralgro or left intact and implanted with Synovex S. Cattle were slaughtered after either 190, 246 or 315 days of high-energy feeding, and the right side of each carcass was electrically stimulated. Sensory analysis was conducted on longissimus dorsi steaks after 5 days aging and Warner-Bratzler shear force (WBS) was measured after 5, 10 and 15 days aging. Steers had lower (P < 0·05) WBS and more desirable sensory panel scores for juiciness, ease of fragmentation, amount of connective tissue and overall tenderness than all intact treatments. The implanting of weanling bulls with synthetic steroid hormone compounds did not make a practical improvement in beef tenderness. PMID:22059890

Shackelford, S D; Savell, J W; Crouse, J D; Cross, H R; Schanbacher, B D; Johnson, D D; Anderson, M L

1992-01-01

104

The Hypertrophic Marchigiana: physical and biochemical parameters for meat quality evaluation  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study was to evaluate the meat quality of double muscled Marchigiana young bulls characterized by different genotypes for the hypertrophy: normal and mutated (heterozygous). Calpain and calpastatin activities were determined to verify the state of aging meat on a sample of Longissimus thoracis muscle (XIII thoracic rib) taken at slaughtering (0h) and after 24 hours (24h). After 14 days of aging, another sample of muscle was taken to evaluate physical and chemical parameters of meat quality. The results showed a better meat quality of mutated animals respect normal animals. Another interesting result was the correlation between the biochemical parameters and some physical parameters, such as WBS (Warner Bratzler Shear Force), CL (Cooking loss). These results showed the relationship between the proteolytic activity of calpain system and meat tenderness.

F. Vincenti; S. Failla; S. Gigli; E. Lasagna; V. Landi; A. Mangione; C. Berti; F. M. Sarti

2010-01-01

105

Effect of South African beef production systems on post-mortem muscle energy status and meat quality.  

Science.gov (United States)

Post-slaughter muscle energy metabolism meat colour of South African production systems were compared; steers (n=182) of Nguni, Simmental Brahman crossbreds were reared on pasture until A-, AB-, or B-age, in feedlot until A-AB-age. After exsanguination carcasses were electrically stimulated (400 V for 15 s). M. longissimus dorsi muscle energy samples were taken at 1, 2, 4 and 20 h. Post-mortem samples for meat quality studies were taken at 1, 7 and 14 days post-mortem. Production systems affected muscle glycogen, glucose, glucose-6-P, lactic acid, ATP, creatine-P glycolytic potential (P0.5) water holding capacity, drip loss, and Warner Bratzler shear force. Muscle energy only affected muscle contraction of the A-age-pasture system (shortest sarcomere length of 1.66 ?m vs 1.75 ?m highest WBS of 6 kg vs 5 kg 7 days post-mortem). PMID:23305833

Frylinck, L; Strydom, P E; Webb, E C; du Toit, E

2012-11-29

106

Effects of genetic variants for the calpastatin gene on calpastatin activity and meat tenderness in Hanwoo (Korean cattle).  

UK PubMed Central (United Kingdom)

This study was designed to investigate the effects of calpastatin genotypes determined by PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) on calpastatin activity (CAC) and Warner-Bratzler Shear Force (WBS). Longissimus muscles were prepared from 379 Hanwoo bulls aged approximately 20months. The selection of PCR primers was based on exons (27 and 28) of the bovine calpastatin cDNA sequences, and genetic variants were detected by SSCP analysis using Taq I restriction enzymes. Sequencing analysis confirmed 4 restriction sites (nucleotide positions 52, 67, 796, and 1369), and a genetic variant was verified at a nucleotide position 641 (C/T substitutions) based on sequences (AF281256). The CAST28 genotypes showing allele frequencies of C (0.429) and T (0.571) were significantly associated with CAC and WBS. A significant positive residual correlation (r=0.121, P=0.02) between CAC and WBS was obtained.

Chung H; Davis M

2012-03-01

107

Organoleptic properties of meat from Altamurana and Trimeticcio lambs slaughtered at two different ages  

Directory of Open Access Journals (Sweden)

Full Text Available The experiment was performed with thirty-two Altamurana and Trimeticcio lambs slaughtered at 42 and at 70 days of age. Meat organoleptic characteristics were determined on samples of M. Longissimus lumborum and Longissimus thoracis. Colour parameters were not affected by genotype, while L* value and index of yellow decreased (P<0.01 and P<0.05, respectively) as age of slaughtering increased. Meat from Altamurana lambs showed lower juiciness (P<0.01) and fatness (P<0.05) than Trimeticcio lambs. No genotype and age of slaughtering effects were found for Warner-Bratzler shear force (WBSF) values. Meat from younger lambs was more tender and chewable (P<0.01) but less juicy (P<0.001) and fatty (P<0.05) than meat from lambs slaughterd at 70 days.

R. Marino; A. Braghieri; G. Gliatta; F. Napolitano; A. Santillo; T. Zezza; A. Girolami

2010-01-01

108

New developments in shockwave technology intended for meat tenderization: Opportunities and challenges. A review.  

UK PubMed Central (United Kingdom)

Meat tenderness is an important quality parameter determining consumer acceptance and price. Meat tenderness is difficult to ensure in the global meat chain because the production systems are not always aiming at this purpose (ex.: cattle derived from milk production) and by the existence within the carcass of "tough" primals. Different methods can be used by the meat industry to improve meat tenderness each with its advantages and drawbacks. The application of hydrodynamic pressure or shockwaves has showed outstanding improvements by reducing the Warner Bratzler Shear Force by 25% or more. However, the technology has not penetrated into the market as first systems were based on the use of explosives and further developments seemed to lack the robustness to fulfill industrial requirements. The present paper describes the main challenges to construct a prototype for the continuous treatment of meat by shockwaves based on electrical discharges under water. Finally, improvements on the tenderness of meat by using the novel prototype are presented.

Bolumar T; Enneking M; Toepfl S; Heinz V

2013-12-01

109

Growth and carcass characteristics of cattle and buffalo breeds reared on a dry zone pasture in Sri Lanka (Ceylon).  

UK PubMed Central (United Kingdom)

Growth and carcass characteristics were measured on calves from three cattle breeds-the Sinhala, Red Sindhi and Friesian-and two buffalo breeds-the local buffalo and Murrah. The growth study was carried out on Brachiaria brizantha pasture over a period of 48 weeks. The two buffalo breeds grew fastest followed by the two Bos indicus breeds. The Friesian cattle grew at the slowest rate. The Sinhala and local buffalo had normal haematocrit values while the values for all other breeds were lower. The Sinhala and local buffalo had the highest carcass dressing percentages and the highest muscle; bone ratios. Tenderness measured by Warner-Bratzler shear force values and palatability scores by a taste panel were similar for meat from cattle and buffalo.

Matsukawa T; Tilakaratne N; Buvanendran V

1976-08-01

110

Growth and carcass characteristics of cattle and buffalo breeds reared on a dry zone pasture in Sri Lanka (Ceylon).  

Science.gov (United States)

Growth and carcass characteristics were measured on calves from three cattle breeds-the Sinhala, Red Sindhi and Friesian-and two buffalo breeds-the local buffalo and Murrah. The growth study was carried out on Brachiaria brizantha pasture over a period of 48 weeks. The two buffalo breeds grew fastest followed by the two Bos indicus breeds. The Friesian cattle grew at the slowest rate. The Sinhala and local buffalo had normal haematocrit values while the values for all other breeds were lower. The Sinhala and local buffalo had the highest carcass dressing percentages and the highest muscle; bone ratios. Tenderness measured by Warner-Bratzler shear force values and palatability scores by a taste panel were similar for meat from cattle and buffalo. PMID:968951

Matsukawa, T; Tilakaratne, N; Buvanendran, V

1976-08-01

111

Llama Meat Nutritional Properties  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study was to determine the chemical composition of the muscle Longissimus thoracis taken from 20 llama males, reared in the Andean region, slaughtered at an age of 25 months and at a mean final body weight of 74kg. Llama meat showed a low fat (3.51%) and cholesterol content (58.16mg/100g), a good protein content (22.42%) and an ash content of 3.06%. The Warner-Bratzler shear force values determined in llama meat was 6.56 kg/cm2. This study confirmed that llama meat is healthy and nutritious, and represents a good source of proteins for Andean population.

P. Polidori; C. Renieri; M. Antonini; G. Lebboroni

2010-01-01

112

Effect of summer forage species grazed during finishing on animal performance, carcass quality, and meat quality.  

Science.gov (United States)

Angus-cross steers (n = 60) were used to assess the effect of forage species [alfalfa (AL; Medicago sativa L.), bermudagrass (BG; Cynodon dactylon), chicory (CH; Cichorium intybus L.), cowpea (CO; Vigna unguiculata L.), and pearl millet (PM; Pennisetum glaucum (L. R Br.)] in replicated 2-ha paddocks for finishing on cattle performance, carcass quality, and meat quality in a 2-yr study. Steers were blocked by BW and assigned randomly to finishing-forage treatments before the start of the experiment. Steers grazing AL and CH had greater (P 1 kg/d). Finishing on legumes (AL and CO) increased dressing percentage, reduced Warner-Bratzler shear force values, and increased consumers preference, whereas finishing on grasses (BG and PM) enhanced anticarcinogenic fatty acid concentrations. PMID:23825343

Schmidt, J R; Miller, M C; Andrae, J G; Ellis, S E; Duckett, S K

2013-07-03

113

Working chute behavior of feedlot cattle can be an indication of cattle temperament and beef carcass composition and quality.  

Science.gov (United States)

The relationship between working chute temperament and beef carcass quality traits were measured on 183 crossbred feedlot steers. Steers were weighed and sorted into 16 pens and weighed every 28 days. Temperament was evaluated as exit velocity (EV), chute score (CS), and catch score (CAPS). Tissue samples were collected for DNA profile including docility (IGENITY®, Merial Limited, Duluth, GA, U.S.A). Steers were harvested at 14 to 16 months of age (606 ± 52 kg). Exit velocity increased and CS and CAPS values declined over time. Steers receiving a lower CAPS score had more marbling (P = 0.02). Ribeye steaks from steers with a slow first recorded EV were more tender (P = 0.02) than steaks from faster EV steers. IGENITY® docility index had a positive (P = 0.09) correlation (r = 0.15) with Warner-Bratzler shear force (WBS) indicating a higher docility index was loosely associated with tougher meat. PMID:21546170

Hall, Noah L; Buchanan, David S; Anderson, Vernon L; Ilse, Breanne R; Carlin, Kasey R; Berg, Eric P

2011-04-09

114

Calcium and potassium content in beef: Influences on tenderness and associations with molecular markers in Nellore cattle.  

UK PubMed Central (United Kingdom)

Calcium (Ca) and potassium (K) are essential nutrients in animal nutrition. Furthermore, the Ca content can influence meat tenderness because it is needed by the proteolytic system of calpains and calpastatins, major factors in postmortem tenderization of skeletal muscles. K content, which is needed for muscle contraction, can also affect meat tenderness. This study showed that K positively affects the Warner-Bratzler shear force (WBSF), measured at 14days of meat aging, which means that higher levels of K are related to lower meat tenderness. Additionally, a significant effect (P?0.015) of a SNP in the calcium-activated neutral protease 1 (CAPN1) gene on Ca content was observed. Metal content in beef can affect not only nutritional values but also meat quality traits. Part of this effect may be related to variation in specific genes.

Tizioto PC; Gromboni CF; de Araujo Nogueira AR; de Souza MM; de Alvarenga Mudadu M; Tholon P; Rosa Ado N; Tullio RR; Medeiros SR; Nassu RT; de Almeida Regitano LC

2014-01-01

115

Introduction to turbulent shear flows  

Energy Technology Data Exchange (ETDEWEB)

Classification of turbulent shear flows, equations governing fluid motions, and eddy viscosity closure models of turbulence are discussed. Flow visualization, hot-wire anemometry, laser Doppler velocimetry, and conditional sampling techniques are described. Wall flow measurement is considered. (ESA)

Ligrani, P.M.

1983-01-01

116

Shear behaviour of ferrocement plates  

Directory of Open Access Journals (Sweden)

Full Text Available Ferrocement members can be used in the form of plates Such as for walling unit, marine structures etc. Such plates are subjected to shear buckling hence shear resistance capacity of plate need to be verified. Various authors have studied shear behaviour on different specimens such as box beams, panels, and plates. The ansys software used for finite element analysis (FEM) of plates. In the present study an attempt is made to observe behaviour of ferrocement plate with various mesh patterns. The results gives that Increasing the volume fraction (VF) of the wire mesh layer subsequently increases the shear carrying capacity of the plate To attain this advantage, supports and loading points should be design and strengthened to prevent local failure, Shear behaviour of ferrocement plates (SBFP).The stress intensity is determined using FEM (Ansys) and compared with the available results. it is observed that stress intensity as well as cracking shear strength of plate depends upon volume fraction. the available equations from literature can be used for analysis of mesh plate.

MADHURI N.SAVALE; PROF. P. M.ALANDKAR

2013-01-01

117

Effect of high shear on proteins.  

UK PubMed Central (United Kingdom)

Shear is present in almost all bioprocesses and high shear is associated with processes involving agitation and emulsification. The purpose of this study is to investigate the effect of high shear and high shear rate on proteins. Two concentric cylinder-based shear systems were used. One was a closed concentric-cylinder shear device (CCSD) and the other was a homogenizer with a rotor/stator assembly. Mathematical modeling of these systems allowed calculation of the shear rate and shear. The CCSD generated low shear rates (a few hundred s(-1)), whereas the homogenizer could generate very high shear rates (> 10(5) s(-1)). High shear could be achieved in both systems by increasing the processing time. Recombinant human growth hormone (rhGH) and recombinant human deoxyribonuclease (rhDNase) were used as the model proteins in this study. It was found that neither high shear nor high shear rate had a significant effect on protein aggregation. However, a lower melting temperature and enthalpy were detected for highly sheared rhGH by using scanning microcalorimetry, presumably due to some changes in protein's conformation. Also, SDS-PAGE indicated the presence of low molecular-weight fragments, suggesting that peptide bond breakage occurred due to high shear. rhDNase was relatively more stable than rhGH under high shear. No conformational changes and protein fragments were observed. (c) 1996 John Wiley & Sons, Inc.

Maa YF; Hsu CC

1996-08-01

118

Modeling of shear wall buildings  

International Nuclear Information System (INIS)

Many nuclear power plant buildings, for example, the auxiliary building, have reinforced concrete shear walls as the primary lateral load resisting system. Typically, these walls have low height to length ratio, often less than unity. Such walls exhibit marked shear lag phenomenon which would affect their bending stiffness and the overall stress distribution in the building. The deformation and the stress distribution in walls have been studied which is applicable to both the short and the tall buildings. The behavior of the wall is divided into two parts: the symmetric flange action and the antisymmetry web action. The latter has two parts: the web shear and the web bending. Appropriate stiffness equations have been derived for all the three actions. These actions can be synthesized to solve any nonlinear cross-section. Two specific problems that of lateral and torsional loadings of a rectangular box have been studied. It is found that in short buildings shear lag plays a very important role. Any beam type formulation which either ignores shear lag or includes it in an idealized form is likely to lead to erroneous results. On the other hand a rigidity type approach with some modifications to the standard procedures would yield nearly accurate answers. (orig.)

1984-01-01

119

Mass loading in velocity shears  

Energy Technology Data Exchange (ETDEWEB)

An analysis is presented on the motion of contaminant ions picked up by the solar wind within velocity shears. An expression is obtained for the ion density in terms of the flow speed across the velocity shear. It is argued that enhanced densities occur in the region where the flow speed is small and that local values may become significantly larger than the ion density outside the velocity shear. A comparison is made with measurements obtained across the plasma wake of comet Giacobini{endash}Zinner with the International Cometary Explorer (ICE) spacecraft. Within the velocity shear of that comet{close_quote}s ionosheath the cometary ion density becomes large and reaches values that are different from those expected when the ion population depends only on the ionization of a uniform outflow of neutral particles from the cometary nucleus. The enhanced plasma density expected within the velocity shear is compatible with the shape of the density profile of contaminant ions detected in that region. {copyright} {ital 1996 American Institute of Physics.}

Perez-de-Tejada, H.; Durand-Manterola, H. [Institute of Geophysics, National University of Mexico, D.F. 04510 (Mexico)

1996-02-01

120

Shear stress and plaque development.  

UK PubMed Central (United Kingdom)

Although traditional cardiovascular risk factors 'prime the soil' for atherogenesis systemically, atherosclerosis primarily occurs in a site-specific manner with a predilection towards the inner wall of curvatures and outer wall of bifurcations with sparing of flow-dividers. Wall shear stress is a frictional force exerted parallel to the vessel wall that leads to alteration of the endothelial phenotype, endothelial cell signaling, gene and protein expression leading to a proinflammatory phenotype, reduced nitric oxide availability and disruption of the extracellular matrix, which in turn leads to plaque development. Clinical and experimental data are emerging that suggest the pathobiology associated with abnormal wall shear stress results in atherosclerotic plaque development and progression.

Dhawan SS; Avati Nanjundappa RP; Branch JR; Taylor WR; Quyyumi AA; Jo H; McDaniel MC; Suo J; Giddens D; Samady H

2010-04-01

 
 
 
 
121

Fruit tree pruning shear blade  

UK PubMed Central (United Kingdom)

The utility model relates to a gardening tool part which is a pruning shears blade for fruiters. The blade comprises a blade back <1>, an edge <2>, an outer lateral surface <3>, an internal surface <6>, and an axes hole <5>. The difference is that the internal surface of the blade is formed by butting at lest two surfaces. One is a friction surface <7> near the blade back anther is an equilibrium surface <8> near the edge. The joint of the two surfaces form an outer convex obtuse angle. Since the internal blade is provided with the equilibrium surface <8>, the fruiter pruning shears adopting the above scheme can conquer the inward pressure on the outer blade prevent the blade to bite with the anvil tablets. The utility model supports the condition that the shaft location moves to the blade instead of the guiding function of the blade internal surface around the shaft. Compared with the prior art, the distance of cut pressure point of the shear and shaft is very near, which is equivalent to shorten the lever resistance arm. The utility model has obviously save labor effect and higher property of the fruit pruning shear.

JIANJUN TENG

122

Meniscal shear stress for punching.  

Science.gov (United States)

Aim: Experimental determination of the shear stress for punching meniscal tissue. Methods: Meniscectomy (surgical treatment of a lesion of one of the menisci) is the most frequently performed arthroscopic procedure. The performance of a meniscectomy is not optimal with the currently available instruments. To design new instruments, the punching force of meniscal tissue is an important parameter. Quantitative data are unavailable. The meniscal punching process was simulated by pushing a rod through meniscal tissue at constant speed. Three punching rods were tested: a solid rod of Oslash; 3.00 mm, and two hollow tubes (Oslash; 3.00-2.60 mm) with sharpened cutting edges of 0.15 mm and 0.125 mm thick, respectively. Nineteen menisci acquired from 10 human cadaveric knee joints were punched (30 tests). The force and displacement were recorded from which the maximum shear stress was determined (average added with three times the standard deviation). Results: The maximum shear stress for the solid rod was determined at 10.2 N/mm2. This rod required a significantly lower punch force in comparison with the hollow tube having a 0.15 mm cutting edge (plt;0.01). Conclusions: The maximum shear stress for punching can be applied to design instruments, and virtual reality training environments. This type of experiment is suitable to form a database with material properties of human tissue similar to databases for the manufacturing industry. PMID:20799169

Tuijthof, Gabrielle J M; Meulman, Hubert N; Herder, Just L; van Dijk, C Niek

123

Measuring shear viscosity using correlations  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Measurements of transverse momentum fluctuations can be used to determine the shear viscosity [1]. We use current data to estimate the viscosity-to-entropy ratio in the range from 0.08 to 0.3, and discuss how future measurements can reduce this uncertainty.

Gavin, Sean; Abdel-Aziz, Mohamed

2007-09-01

124

Shear deformation laminate theory used for sandwiches  

Directory of Open Access Journals (Sweden)

Full Text Available The shear deformation laminate theory is very useful for the calculation of the sandwich composites. Sandwich can be defined as a special laminate with three layers and therefore can be modeled using shear deformation laminate theory by neglecting of membrane and bending deformations in the core and the shear deformation in the facings.

E. Kormaníková; Ilija Mamuzi?

2011-01-01

125

Does shear flow stabilize an immersed thread?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The stability of one liquid thread immersed in a fluid in a shear field is considered by linear stability analysis. A constant shear stress is imposed far away from the thread. The shear flow tends to deform and elongate the thread. The stability of the thread is characterized by the growth rate of ...

Gunawan, A.Y.; Molenaar, J.; Ven, A.A.F., van der

126

Shear strength of members without transverse reinforcement as function of critical shear crack width  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper investigates the shear strength of beams and one-way slabs without stirrups based on the opening of a critical shear crack. The shear-carrying mechanisms after the development of this crack are investigated. On this basis, a rational model is developed to estimate the shear strength of me...

Muttoni, Aurelio; Fernández Ruiz, Miguel

127

Apparatus for shearing spent nuclear fuel assemblies  

International Nuclear Information System (INIS)

[en] A method and apparatus are described for shearing spent nuclear fuel assemblies of the type comprising an array of fuel pins disposed within an outer metal shell or shroud. A spent fuel assembly is first compacted in a known manner and then incrementally sheared using fixed and movable shear blades having matched laterally projecting teeth which slidably intermesh to provide the desired shearing action. Incremental advancement of the fuel assembly after each shear cycle is limited to a distance corresponding to the lateral projection of the teeth to ensure fuel assembly breakup into small uniform segments which are amenable to remote chemical processing

1980-01-01

128

Shear stress and plaque development.  

Science.gov (United States)

Although traditional cardiovascular risk factors 'prime the soil' for atherogenesis systemically, atherosclerosis primarily occurs in a site-specific manner with a predilection towards the inner wall of curvatures and outer wall of bifurcations with sparing of flow-dividers. Wall shear stress is a frictional force exerted parallel to the vessel wall that leads to alteration of the endothelial phenotype, endothelial cell signaling, gene and protein expression leading to a proinflammatory phenotype, reduced nitric oxide availability and disruption of the extracellular matrix, which in turn leads to plaque development. Clinical and experimental data are emerging that suggest the pathobiology associated with abnormal wall shear stress results in atherosclerotic plaque development and progression. PMID:20397828

Dhawan, Saurabh S; Avati Nanjundappa, Ravi P; Branch, Jonathan R; Taylor, W Robert; Quyyumi, Arshed A; Jo, Hanjoong; McDaniel, Michael C; Suo, Jin; Giddens, Don; Samady, Habib

2010-04-01

129

Controlled shear/tension fixture  

Energy Technology Data Exchange (ETDEWEB)

A test fixture for simultaneously testing two material test samples is provided. The fixture provides substantially equal shear and tensile stresses in each test specimens. By gradually applying a load force to the fixture only one of the two specimens fractures. Upon fracture of the one specimen, the fixture and the load train lose contact and the second specimen is preserved in a state of upset just prior to fracture. Particular advantages of the fixture are (1) to control the tensile to shear load on the specimen for understanding the effect of these stresses on the deformation behavior of advanced materials, (2) to control the location of fracture for accessing localized material properties including the variation of the mechanical properties and residual stresses across the thickness of advanced materials, (3) to yield a fractured specimen for strength measurement and an unfractured specimen for examining the microstructure just prior to fracture.

Hsueh, Chun-Hway (Knoxville, TN); Liu, Chain-tsuan (Knoxville, TN); George, Easo P. (Knoxville, TN)

2012-07-24

130

On hydromagnetic turbulent shear flow  

International Nuclear Information System (INIS)

Hydromagnetic turbulent shear flow of viscous incompressible, electrically conducting fluid between two infinite porous horizontal planes in presence of a uniform transverse magnetic field has been studied by the semi-empirical method. The expressions for the mean distributions for velocity and magnetic field have been obtained when the surfaces of the channel are nonconducting and conducting. Numerical results are shown graphically. (author). 9 refs.

1989-01-01

131

Shear localization in a tungsten heavy alloy  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the results of an investigation into the dynamic shearing deformations of a W-Ni-Fe heavy alloy containing 91% W and with the Ni and Fe in a 7:3 ratio. The techniques used to develop the dynamic shearing deformations are the torsional Kolsky bar and pressure shear plate impact. The torsional Kolsky bar generates shear rates up to 10(exp 3)/s for times of several hundred micro s. The pressure-shear plate impact technique subjects the deformed material to shearing under superimposed hydrostatic pressure and develops shear rates as high as 1O(exp 5)/s for times of one microsec. Adiabatic shear localization has been observed in the high-rate shearing tests; relatively narrow shear bands are formed, followed immediately by catastrophic fracture. The deformed microstructures are examined using scanning electron microscopy, optical microscopy, and quantitative image analysis of micrographs. Examination of the deformed microstructures supplies new insight into the mechanisms through which large dynamic shearing deformations occur in this heavy tungsten alloy.

Ramesh, K.T.; Yadav, S.; Davis, J.A.

1995-12-01

132

Stability Criteria of 3D Inviscid Shears  

CERN Multimedia

The classical plane Couette flow, plane Poiseuille flow, and pipe Poiseuille flow share some universal 3D steady coherent structure in the form of "streak-roll-critical layer". As the Reynolds number approaches infinity, the steady coherent structure approaches a 3D limiting shear of the form ($U(y,z), 0, 0$) in velocity variables. All such 3D shears are steady states of the 3D Euler equations. This raises the importance of investigating the stability of such inviscid 3D shears in contrast to the classical Rayleigh theory of inviscid 2D shears. Several general criteria of stability for such inviscid 3D shears are derived. In the Appendix, an argument is given to show that a 2D limiting shear can only be the classical laminar shear.

Li, Y Charles

2009-01-01

133

Energy Efficiency and Renewable Energy Research, Development, and Deployment in Meeting Greenhouse Gas Mitigation Goals: The Case of the Lieberman-Warner Climate Security Act of 2007 (S.2191)  

Energy Technology Data Exchange (ETDEWEB)

The U.S. federal government is considering actions to reduce greenhouse gas emissions. Renewable energy and energy efficiency technologies could help reduce greenhouse gas emissions, so the cost of these technologies could significantly influence the overall cost of meeting greenhouse gas limits. This paper examines the potential benefit of reduced technology cost by analyzing the case of the Lieberman-Warner Climate Security Act of 2007 (S.2191). This act had a goal of reducing national carbon emissions in 2050 to levels 72 percent below 2006 emission levels. In April 2008, the U.S. Department of Energy, Energy Information Administration (EIA) published an analysis of the effects of S.2191 on the U.S. energy sector. This report presents a similar analysis: both analyses examined the impacts of S.2191, and both used versions of the National Energy Modeling System. The analysis reported here used modified technology assumptions to reflect U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy (EERE) program goals. The results show that achieving EERE program goals could reduce the cost of meeting greenhouse gas limits, reduce the cost of renewable electricity generation and biofuels, and reduce energy intensity.

Showalter, S.; Wood, F.; Vimmerstedt, L.

2010-06-01

134

HAND-OPERATED GRASS SHEARS  

UK PubMed Central (United Kingdom)

The invention proposes mounting a handle arrangement (HA) in a pivotable manner relative to a blade support (GK, SK) or a cutting head of a blade support about a pivoting axis in order to produce hand-operated grass shears, said pivoting axis running perpendicular to the cutting plane of the blade arrangement. Advantageously, a pulling cable (ZS) is used for the force transmission between the handle arrangement (HA) and the blade arrangement (OM, UM), said pulling cable running along the pivoting axis (SA) at least along some sections.

REICHART VINCENT

135

Mixing in shear thinning fluids  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english In the present study, a CFD characterization of the flow generated by curved-blade impellers in a cylindrical unbaffled vessel was carried out. The tank diameter was 300 mm, with a flat bottom. The liquid height was equal to the vessel diameter. The fluids simulated have a shear thinning behavior. Analyses concern the effect of the impeller speed, the fluid rheology and the number of impeller blades on the induced flow patterns and the power consumption. The predictions were compared with literature data and a satisfactory agreement was found.

Ameur, H.; Bouzit, M.

2012-06-01

136

Mixing in shear thinning fluids  

Directory of Open Access Journals (Sweden)

Full Text Available In the present study, a CFD characterization of the flow generated by curved-blade impellers in a cylindrical unbaffled vessel was carried out. The tank diameter was 300 mm, with a flat bottom. The liquid height was equal to the vessel diameter. The fluids simulated have a shear thinning behavior. Analyses concern the effect of the impeller speed, the fluid rheology and the number of impeller blades on the induced flow patterns and the power consumption. The predictions were compared with literature data and a satisfactory agreement was found.

H. Ameur; M. Bouzit

2012-01-01

137

Development of the FFTF rotary shear  

International Nuclear Information System (INIS)

In support of the Process Facility Modifications (PFM) Project, development testing has been conducted by Rockwell Hanford Operations (Rockwell) on various methods of mechanically segmenting Fast Flux Test Facility (FFTF) fuel. Initial tests, using alluminum oxide-filled stainless steel tubing, were performed at Oak Ridge National Laboratory (ORNL) to evaluate the performance of a reciprocating blade bundle shear. Feasibility tests completed in 1984 demonstrated that slow-speed rotary shearing offered improvements to PFM over the reciprocating blade bundle shear. Development testing, completed in 1986 at Rockwell using a prototype rotary shear, established specific equipment configurations and identified pertinent operating parameters for incorporating slow-speed rotary shearing into PFM. This document discusses the final test results of the FFTF fuel shear development test.

1987-01-01

138

Some aspects of fluctuating vertical wind shears  

Energy Technology Data Exchange (ETDEWEB)

Fluctuating vertical shears of wind speed have been measured using an array of towers. The statistical distributions of these shears are compared with formulas proposed by Fichtl (1971, 1972) and good agreement is found. A comparison of Fichtl's formula for the standard deviation of the fluctuating shears with a more empirical one proposed by Ramsdell (1978) shows that the latter is consistent with the former under the proper conditions. The probability of occurrence of extreme shears in speed is discussed. Directional shears are not treated. Fluctuating shears two or more times larger than the mean values are shown to be readily obtainable, and their likelihood increases as the mean measuring height increases if ..delta..Z is held fixed.

Doran, J.C.

1981-05-01

139

Shear strength properties of wet granular materials  

CERN Multimedia

We investigate shear strength properties of wet granular materials in the pendular state (i.e. the state where the liquid phase is discontinuous) as a function of water content. Sand and glass beads were wetted and tested in a direct shear cell and under various confining pressures. In parallel, we carried out three-dimensional molecular dynamics simulations by using an explicit equation expressing capillary force as a function of interparticle distance, water bridge volume and surface tension. We show that, due to the peculiar features of capillary interactions, the major influence of water content over the shear strength stems from the distribution of liquid bonds. This property results in shear strength saturation as a function of water content. We arrive at the same conclusion by a microscopic analysis of the shear strength. We propose a model that accounts for the capillary force, the granular texture and particle size polydispersity. We find fairly good agreement of the theoretical estimate of the shear...

Richefeu, V; Radja"i, F; Richefeu, Vincent; Youssoufi, Moulay Sa\\"{i}d El; Radja\\"{i}, Farhang

2006-01-01

140

Edge turbulence scaling with shear flow  

International Nuclear Information System (INIS)

A formula relating turbulence levels with arbitrary shear flow is derived. When the diffusion coefficient is made a functional of the corresponding turbulence level, it is found that the scaling laws governing turbulence suppression are considerably modified. The results are compared with known formulas in various limiting cases, indicating that turbulence suppression mainly pertains in the moderate shear flow regime. The results also show that a flattened (steep) radial equilibrium gradient tends to enhance (eliminate) turbulence suppression due to the shear flow.

1992-01-01

 
 
 
 
141

Coronal magnetic fields produced by photospheric shear  

Energy Technology Data Exchange (ETDEWEB)

The magneto-frictional method is used for computing force free fields to examine the evolution of the magnetic field of a line dipole, when there is relative shearing motion between the two polarities. It found that the energy of the sheared field can be arbitrarily large compared with the potential field. It is also found that it is possible to fit the magnetic energy, as a function of shear, by a simple functional form.

Sturrock, P.A.; Yang, W.H.

1987-10-01

142

Coronal magnetic fields produced by photospheric shear  

International Nuclear Information System (INIS)

The magneto-frictional method is used for computing force free fields to examine the evolution of the magnetic field of a line dipole, when there is relative shearing motion between the two polarities. It found that the energy of the sheared field can be arbitrarily large compared with the potential field. It is also found that it is possible to fit the magnetic energy, as a function of shear, by a simple functional form.

1987-01-01

143

Shear wall experiments and design in Japan  

Energy Technology Data Exchange (ETDEWEB)

This paper summarizes the results of recent survey studies on the available experimental data bases and design codes/standards for reinforced concrete (RC) shear wall structures in Japan. Information related to the seismic design of RC reactor buildings and containment structures was emphasized in the survey. The seismic requirements for concrete structures, particularly those related to shear strength design, are outlined. Detailed descriptions are presented on the development of Japanese shear wall equations, design requirements for containment structures, and ductility requirements.

Park, Y.J.; Hofmayer, C.

1994-12-01

144

Measurement of temperature using speckle shearing interferometry.  

UK PubMed Central (United Kingdom)

A laser speckle shearing interferometric technique is used for measuring the temperature profile inside a gaseous flame. The experimental results are compared with the values obtained by a thermocouple and also by speckle photography. Good agreement is seen among the temperatures measured by speckle shearing interferometry, speckle photography, and the thermocouple. Speckle shearing interferometry is easier to implement than speckle photography. This is because in speckle shearing interferometry the accurate positions of the fringes can be known without point-by-point analysis and correction for the halo effect.

Shakher C; Nirala AK

1994-04-01

145

Measurement of temperature using speckle shearing interferometry.  

Science.gov (United States)

A laser speckle shearing interferometric technique is used for measuring the temperature profile inside a gaseous flame. The experimental results are compared with the values obtained by a thermocouple and also by speckle photography. Good agreement is seen among the temperatures measured by speckle shearing interferometry, speckle photography, and the thermocouple. Speckle shearing interferometry is easier to implement than speckle photography. This is because in speckle shearing interferometry the accurate positions of the fringes can be known without point-by-point analysis and correction for the halo effect. PMID:20885553

Shakher, C; Nirala, A K

1994-04-10

146

Dynamic shear deformation in high purity Fe  

Energy Technology Data Exchange (ETDEWEB)

The forced shear test specimen, first developed by Meyer et al. [Meyer L. et al., Critical Adiabatic Shear Strength of Low Alloyed Steel Under Compressive Loading, Metallurgical Applications of Shock Wave and High Strain Rate Phenomena (Marcel Decker, 1986), 657; Hartmann K. et al., Metallurgical Effects on Impact Loaded Materials, Shock Waves and High Strain rate Phenomena in Metals (Plenum, 1981), 325-337.], has been utilized in a number of studies. While the geometry of this specimen does not allow for the microstructure to exactly define the location of shear band formation and the overall mechanical response of a specimen is highly sensitive to the geometry utilized, the forced shear specimen is useful for characterizing the influence of parameters such as strain rate, temperature, strain, and load on the microstructural evolution within a shear band. Additionally, many studies have utilized this geometry to advance the understanding of shear band development. In this study, by varying the geometry, specifically the ratio of the inner hole to the outer hat diameter, the dynamic shear localization response of high purity Fe was examined. Post mortem characterization was performed to quantify the width of the localizations and examine the microstructural and textural evolution of shear deformation in a bcc metal. Increased instability in mechanical response is strongly linked with development of enhanced intergranular misorientations, high angle boundaries, and classical shear textures characterized through orientation distribution functions.

Cerreta, Ellen K [Los Alamos National Laboratory; Bingert, John F [Los Alamos National Laboratory; Trujillo, Carl P [Los Alamos National Laboratory; Lopez, Mike F [Los Alamos National Laboratory; Gray, George T [Los Alamos National Laboratory

2009-01-01

147

BIPOLAR SCISSORS WITH CURVED SHEAR BLADES  

UK PubMed Central (United Kingdom)

Bipolar scissors ( 1 ) with two curved shear blades ( 2, 3 ) are provided with insulation on each of the shear blades ( 2, 3 ), which is distributed on the two shear blades ( 2, 3 ) such that each of the shear blades ( 2, 3 ) is insulated only over a part of its length, however the insulation is continuous in this area, i.e. at each of the two shear blades ( 2, 3 ) only a single longitudinal area is coated in a lamellar and uninterrupted fashion with insulation ( 11, 12 ). The insulation ( 11, 12 ) of each of the shear blades ( 2 ) complements each other in the closed position of the scissors ( 11 ) such that the overall insulation essentially extends over the entire length of the two shear blades ( 2, 3 ).; This way, each piece of the curved insulation follows the curvature of the shear blade, and in case of mounted insulating plates, there is little stress and the insulation can also withstand several autoclaving processes without separating from the shear blades ( 2, 3 ).

SUTTER BERT

148

Confined cubic blue phases under shear.  

UK PubMed Central (United Kingdom)

We study the behaviour of confined cubic blue phases under shear flow via lattice Boltzmann simulations. We focus on the two experimentally observed phases, blue phase I and blue phase II. The disclination network of blue phase II continuously breaks and reforms under shear, leading to an oscillatory stress response in time. The oscillations are only regular for very thin samples. For thicker samples, the shear leads to a 'stick-slip' motion of part of the network along the vorticity direction. Blue phase I responds very differently: its defect network undergoes seemingly chaotic rearrangements under shear, irrespective of system size.

Henrich O; Stratford K; Marenduzzo D; Coveney PV; Cates ME

2012-07-01

149

Can shear stress direct stem cell fate?  

UK PubMed Central (United Kingdom)

Mechanical forces are important signals in the development and function of the heart and lung, growth of skin and muscle, and maintenance of cartilage and bone. The specific mechanical force "shear stress" has been implicated as playing a critical role in the physiological responses of blood vessels through endothelial cell signaling. More recently, studies have shown that shear stress can induce differentiation of stem cells toward both endothelial and bone-producing cell phenotypes. This review will highlight current data supporting the role of shear stress in stem cell fate and will propose potential mechanisms and signaling cascades for transducing shear stress into a biological signal.

Stolberg S; McCloskey KE

2009-01-01

150

Low-rise shear wall failure modes  

Energy Technology Data Exchange (ETDEWEB)

A summary of the data that are available concerning the structural response of low-rise shear walls is presented. This data will be used to address two failure modes associated with the shear wall structures. First, data concerning the seismic capacity of the shear walls with emphasis on excessive deformations that can cause equipment failure are examined. Second, data concerning the dynamic properties of shear walls (stiffness and damping) that are necessary to compute the seismic inputs to attached equipment are summarized. This case addresses the failure of equipment when the structure remains functional. 23 refs.

Farrar, C.R. (Los Alamos National Lab., NM (USA)); Hashimoto, P.S. (EQE Engineering, Inc., Costa Mesa, CA (USA)); Reed, J.W. (Benjamin (J.R.) and Associates, Inc., Mountain View, CA (USA))

1991-01-01

151

Novel shear mechanism in nanolayered composites  

Energy Technology Data Exchange (ETDEWEB)

Recent studies have shown that two-phase nanocomposite materials with semicoherent interfaces exhibit enhanced strength, deformability, and radiation damage resistance. The remarkable behavior exhibited by these materials has been attributed to the atomistic structure of the bi-metal interface that results in interfaces with low shear strength and hence, strong barriers for slip transmission due to dislocation core spreading along the weak interfaces. In this work, the low interfacial shear strength of Cu/Nb nanoscale multilayers dictates a new mechanism for shear banding and strain softening during micropillar compression. Previous work investigating shear band formation in nanocrystalline materials has shown a connection between insufficient strain hardening and the onset of shear banding in Fe and Fe-10% Cu, but has also shown that hardening does not necessarily offset shear banding in Pd nanomaterials. Therefore, the mechanisms behind shear localization in nanocrystalline materials are not completely understood. Our findings, supported by molecular dynamics simulations, provide insight on the design of nanocomposites with tailored interface structures and geometry to obtain a combination of high strength and deformability. High strength is derived from the ability of the interfaces to trap dislocations through relative ease of interfacial shear, while deformability can be maximized by controlling the effects of loading geometry on shear band formation.

Mara, Nathan [Los Alamos National Laboratory; Bhattacharyya, Dhriti [Los Alamos National Laboratory; Hirth, John P [Los Alamos National Laboratory; Dickerson, Patricia O [Los Alamos National Laboratory; Misra, Amit [Los Alamos National Laboratory

2009-01-01

152

Shear wall ultimate drift limits  

Energy Technology Data Exchange (ETDEWEB)

Drift limits for reinforced-concrete shear walls are investigated by reviewing the open literature for appropriate experimental data. Drift values at ultimate are determined for walls with aspect ratios ranging up to a maximum of 3.53 and undergoing different types of lateral loading (cyclic static, monotonic static, and dynamic). Based on the geometry of actual nuclear power plant structures exclusive of containments and concerns regarding their response during seismic (i.e.,cyclic) loading, data are obtained from pertinent references for which the wall aspect ratio is less than or equal to approximately 1, and for which testing is cyclic in nature (typically displacement controlled). In particular, lateral deflections at ultimate load, and at points in the softening region beyond ultimate for which the load has dropped to 90, 80, 70, 60, and 50 percent of its ultimate value, are obtained and converted to drift information. The statistical nature of the data is also investigated. These data are shown to be lognormally distributed, and an analysis of variance is performed. The use of statistics to estimate Probability of Failure for a shear wall structure is illustrated.

Duffey, T.A. [Duffy, (T.A.) Tijeras, NM (United States); Goldman, A. [Goldman, (A.), Sandia, Los Alamos, NM (United States); Farrar, C.R. [Los Alamos National Lab., NM (United States)

1994-04-01

153

Shear wall ultimate drift limits  

International Nuclear Information System (INIS)

Drift limits for reinforced-concrete shear walls are investigated by reviewing the open literature for appropriate experimental data. Drift values at ultimate are determined for walls with aspect ratios ranging up to a maximum of 3.53 and undergoing different types of lateral loading (cyclic static, monotonic static, and dynamic). Based on the geometry of actual nuclear power plant structures exclusive of containments and concerns regarding their response during seismic (i.e.,cyclic) loading, data are obtained from pertinent references for which the wall aspect ratio is less than or equal to approximately 1, and for which testing is cyclic in nature (typically displacement controlled). In particular, lateral deflections at ultimate load, and at points in the softening region beyond ultimate for which the load has dropped to 90, 80, 70, 60, and 50 percent of its ultimate value, are obtained and converted to drift information. The statistical nature of the data is also investigated. These data are shown to be lognormally distributed, and an analysis of variance is performed. The use of statistics to estimate Probability of Failure for a shear wall structure is illustrated.

1994-01-01

154

Turbulence suppression by E x B shear in JET optimized shear pulses  

Energy Technology Data Exchange (ETDEWEB)

The authors calculate microinstability growth rates in JET optimized shear plasmas with a comprehensive gyrofluid model, including sheared E x B flows, trapped electrons, and all dominant ion species in realistic magnetic geometry. They find good correlation between E x B shear suppression of microinstabilities and both the formation and collapse of the internal transport barrier.

Beer, M.A.; Budny, R.V.; Challis, C.D.; Conway, G.

2000-01-06

155

Effects of shear stress on the microalgae Chaetoceros muelleri  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The effect of shear stress on the viability of Chaetoceros muelleri was studied using a combination of a rheometer and dedicated shearing devices. Different levels of shear stress were applied by varying the shear rates and the medium viscosities. It was possible to quantify the effect of shear stre...

Michels, Michiel H. A.; van der Goot, Atze J.; Norsker, Niels-Henrik; Wijffels, René H.

156

Vlasov simulation of kinetic shear Alfven waves  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The treatment of kinetic shear Alfven waves in homogeneous magnetized plasmas by means of Vlasov simulation is examined. To this end, the driftkinetic version of the Vlasov-Maxwell equations is solved via various numerical schemes, all employing a grid in (1 + 1)D phase space. Since kinetic shear Al...

Dannert, Tilman; Jenko, Frank

157

Shear Strength of RC Bridge Deck Cantilevers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An experimental and theoretical investigation of the shear strength of reinforced concrete slabs without shear reinforcement is under way at the Ecole Polytechnique Fédérale de Lausanne. The first part of the program consists of 6 tests on two large scale bridge deck cantilevers. The specimens are t...

Vaz Rodrigues, Rui

158

On the state of pure shear  

Directory of Open Access Journals (Sweden)

Full Text Available The algebraic proof of the fundamental theorem concerning pure shear, by making use only of the notion of orthogonal projector, is presented. It has been shown that the state of pure shear is the same for all singular symmetric traceless tensors in E3, up to the rotation.

Jari? Jovo P.; Kuzmanovi? Dragoslav S.; Golubovi? Zoran ?.

2010-01-01

159

Rearrangements and Dilatancy for Sheared Dense Materials  

CERN Multimedia

Constitutive equations are proposed for dense materials, based on the identification of two types of free-volume activated rearrangements associated to shear and compaction. Two situations are studied: the case of an amorphous solid in a stress-strain test, and the case of a lubricant in tribology test. Varying parameters, strain softening, shear thinning, and stick-slip motion can be observed.

Lemaître, A

2001-01-01

160

Shear Localization in a Tungsten Heavy Alloy.  

Science.gov (United States)

This paper presents the results of an investigation into the dynamic shearing deformations of a W-Ni-Fe heavy alloy containing 91% W and with the Ni and Fe in a 7:3 ratio. The techniques used to develop the dynamic shearing deformations are the torsional ...

K. T. Ramesh S. Yadav J. A. Davis

1995-01-01

 
 
 
 
161

Shear instability of fluid interfaces: stability analysis.  

UK PubMed Central (United Kingdom)

We examine the linear stability of fluid interfaces subjected to a shear flow. Our main object is to generalize previous work to an arbitrary Atwood number, and to allow for surface tension and weak compressibility. The motivation derives from instances in astrophysical systems where mixing across material interfaces driven by shear flows may significantly affect the dynamical evolution of these systems.

Alexakis A; Young Y; Rosner R

2002-02-01

162

Method and apparatus for shear wave logging  

Energy Technology Data Exchange (ETDEWEB)

A method and apparatus for shear wave logging which utilizes relatively high frequency sweep control transmission and subsequent correlation of received signals in order to define travel times of horizontally polarized shear and/or torsional wave energy. The apparatus includes specific sonde structure for effecting firm contact of transmitting and receiving elements with the borehole wall.

Hopkins, J.R.; Payton, C.E.; Waters, K.H.

1983-04-19

163

Method and apparatus for shear wave logging  

International Nuclear Information System (INIS)

[en] A method and apparatus for shear wave logging which utilizes relatively high frequency sweep control transmission and subsequent correlation of received signals in order to define travel times of horizontally polarized shear and/or torsional wave energy. The apparatus includes specific sonde structure for effecting firm contact of transmitting and receiving elements with the borehole wall

1983-01-01

164

Shear deformation in granular materials  

Energy Technology Data Exchange (ETDEWEB)

An investigation into the properties of granular materials is undertaken via numerical simulation. These simulations highlight that frictional contact, a defining characteristic of dry granular materials, and interfacial debonding, an expected deformation mode in plastic bonded explosives, must be properly modeled. Frictional contact and debonding algorithms have been implemented into FLIP, a particle in cell code, and are described. Frictionless and frictional contact are simulated, with attention paid to energy and momentum conservation. Debonding is simulated, with attention paid to the interfacial debonding speed. A first step toward calculations of shear deformation in plastic bonded explosives is made. Simulations are performed on the scale of the grains where experimental data is difficult to obtain. Two characteristics of deformation are found, namely the intermittent binding of grains when rotation and translation are insufficient to accommodate deformation, and the role of the binder as a lubricant in force chains.

Bardenhagen, S.G.; Brackbill, J.U. [Los Alamos National Lab., NM (United States); Sulsky, D.L. [Univ. of New Mexico, Albuquerque, NM (United States)

1998-12-31

165

Syn-sedimentary shear zones  

Energy Technology Data Exchange (ETDEWEB)

In deltaic and turbiditic deposits along passive margins, such as the Lower Congo basin on the West African margin, the main deformation is not induced by a regional tectonic stress field but by the increase of the sedimentary load leading to gravitational instabilities. The local stress field in such an environment is drastically influenced by the lithological discontinuities, which can reorientate the principal stresses induced by sedimentary loading. In this paper we document the localization of particular faults, called sedimentary shear zones (SSZ); these are formed along the borders of a sandy channel embedded in more fine-grained sediments, as a function of the lithological contrast. Furthermore we describe the reorientation of the stress field, perpendicular to the channel borders in the channel interior. Examples from 3D seismic lines and field studies in SW Ireland and Tunisia are compared with results from analogue and geomechanical models, leading to an integrated interpretation for the formation of the SSZ. (Author)

Moretti, I.; Maerten, L. [Institut Francais du Petrole, Div. Geologie-Geochimie, Rueil Malmaison, 92 (France); Calassou, S. [TotalFinaElf, Centre Scientifique et Technique, Pau, 64 (France); Victor, P.; Molinaro, M. [Orsay Univ., Lab. Tectonique et Bassins, Orsay, 91 (France)

2003-07-01

166

E × B shear suppression of turbulence in diverted H-mode plasmas: role of edge magnetic shear  

Science.gov (United States)

We show that strong edge magnetic shear, which is generic to divertor plasmas, makes the E × B shearing of turbulence eddys in toroidal geometry more effective. From calculations of the E × B shearing rates for KSTAR edge parameters, we conclude that the enhanced magnetic shear at the diverted KSTAR plasma edge facilitates E × B shear suppression of turbulence and ensuing H-mode transition.

Hahm, T. S.; Na, D. H.; Lee, J. W.; Park, J. W.; Na, Y. S.; Kim, S. S.; Ko, W. H.; Diamond, P. H.; Jhang, Hogun; Jeon, Y. M.

2013-09-01

167

Shear Flows and Shear Viscosity in a Two-Dimensional Yukawa System (Dusty Plasma)  

CERN Document Server

The shear viscosity of a two-dimensional liquid-state dusty plasma was measured experimentally. A monolayer of highly charged polymer microspheres, with a Yukawa interaction, was suspended in a plasma sheath. Two counter-propagating Ar laser beams pushed the particles, causing shear-induced melting of the monolayer and a shear flow in a planar Couette configuration. By fitting the particle velocity profiles in the shear flow to a Navier-Stokes model, the kinematic viscosity was calculated; it was of order 1 mm^2/s, depending on the monolayer's parameters and shear stress applied.

Nosenko, V

2004-01-01

168

Hysteresis models of low-rise shear walls with coupled bending and shear deformations  

International Nuclear Information System (INIS)

[en] Low-rise shear walls are commonly used in both industrial buildings, such as auxiliary buildings at nuclear power plants, and low-rise civil structures. It is important to understand the nonlinear behavior of these structures. Because these walls have strong coupling behavior of bending and shear deformations, and the shear deformations can sometimes be large than the bending deformations. It is necessary to preform experimental and analytical work to derive mathematical models for inelastic analysis. An analytical method is presented in this paper for calculating the shear and bending deformation and generating hysteresis loops for analysis of general low-rise shear wall structural systems

1989-01-01

169

Glass transitions and shear thickening suspension rheology  

CERN Document Server

We introduce a class of simple models for shear thickening and/ or `jamming' in colloidal suspensions. These are based on schematic mode coupling theory (MCT) of the glass transition, having a memory term that depends on a density variable, and on both the shear stress and the shear rate. (Tensorial aspects of the rheology, such as normal stresses, are ignored for simplicity.) We calculate steady-state flow curves and correlation functions. Depending on model parameters, we find a range of rheological behaviours, including `S-shaped' flow curves, indicating discontinuous shear thickening, and stress-induced transitions from a fluid to a nonergodic (jammed) state, showing zero flow rate in an interval of applied stress. The shear thickening and jamming scenarios that we explore appear broadly consistent with experiments on dense colloids close to the glass transition, despite the fact that we ignore hydrodynamic interactions. In particular, the jamming transition we propose is conceptually quite different from...

Holmes, C B; Fuchs, M; Sollich, P

2004-01-01

170

Boundary Shear Stress around Bridge Piers  

Directory of Open Access Journals (Sweden)

Full Text Available This research presents the measurement of boundary shear stress around the base of some elliptical shaped bridge piers using Preston tube technique. The uniform flow was established and a series of measurements having different discharges and channel bed slopes were undertaken. General results are established and then the effects of flow separation on the hydraulic theory are assessed. The Analysis of results shows that behind the bridge piers (horseshoe area); the amount of boundary shear stress reduces dramatically. The figure for the rate of boundary shear stress of nose to end is about ?r = ?n/?e = 3.6. It has a remarkable reduction even in steep slopes. The bed shear stress was found to intensify near the nose of the piers. The distribution of boundary shear stress in both mild and steep channel bed slopes along spanwise direction is presented that may give a valuable perspective of the flow action around piers.

Mirali Mohammadi

2008-01-01

171

Coronal magnetic fields produced by photospheric shear  

International Nuclear Information System (INIS)

The magnetofrictional method for computing force-free fields is used to examine the evolution of the magnetic field of a line dipole, when there is relative shearing motion between the two polarities. It is found that the energy of the sheared field can be arbitrarily large compared with the potential field. It is also found that it is possible to fit the magnetic energy, as a function of shear amplitude, by a simple functional form. The fit parameters depend only on the distribution of normal field in the photosphere and the form of the shearing displacement. They show that the energy is relatively more enhanced if the shear occurs: (1) where the normal field is strongest; and/or (2) in the inner region of the dipole, near the axis; and/or (3) over a large fraction of the dipole area. 22 references.

1988-01-01

172

Coronal magnetic fields produced by photospheric shear  

Energy Technology Data Exchange (ETDEWEB)

The magneto-frictional method for computing force-free fields examines the evolution of the magnetic field of a line dipole, when there is relative shearing motion between the two polarities. The energy of the sheared field can be arbitrarily large compared with the potential field. It is possible to fit the magnetic energy, as a function of shear amplitude, by a simple functional form. The fit parameters depend only on the distribution of normal field in the photosphere and the form of the shearing displacement. The energy is relatively more enhanced if the shear occurs: (1) where the normal field is strongest; (2) in the inner region of the dipole, near the axis; or (3) over a large fraction of the dipole area.

Klimchuk, J.A.; Sturrock, P.A.; Yang, W.H.

1988-04-01

173

Coronal magnetic fields produced by photospheric shear  

Energy Technology Data Exchange (ETDEWEB)

The magnetofrictional method for computing force-free fields is used to examine the evolution of the magnetic field of a line dipole, when there is relative shearing motion between the two polarities. It is found that the energy of the sheared field can be arbitrarily large compared with the potential field. It is also found that it is possible to fit the magnetic energy, as a function of shear amplitude, by a simple functional form. The fit parameters depend only on the distribution of normal field in the photosphere and the form of the shearing displacement. They show that the energy is relatively more enhanced if the shear occurs: (1) where the normal field is strongest; and/or (2) in the inner region of the dipole, near the axis; and/or (3) over a large fraction of the dipole area. 22 references.

Klimchuk, J.A.; Sturrock, P.A.; Yang, W.H.

1988-12-01

174

Experimental study on the adiabatic shear bands  

International Nuclear Information System (INIS)

Four martensitic steels (Z50CDV5 steel, 28CND8 steel, 35NCDV16 steel and 4340 steel) with different hardness between 190 and 600 Hsub(B) (Brinell hardness), have been studied by means of dynamic compressive tests on split Hopkinson pressure bar. Microscopic observations show that the fracture are associated to the development of adiabatic shear bands (except 4340 steel with 190 Hsub(B) hardness). By means of tests for which the deformation is stopped at predetermined levels, the measurement of shear and hardness inside the band and the matrix indicates the chronology of this phenomenon: first the localization of shear, followed by the formation of adiabatic shear band and ultimatly crack initiation and propagation. These results correlated with few simulations by finite elements have permitted to suggest two mecanisms of deformation leading to the formation of adiabatic shear bands in this specific test

1984-01-01

175

Predictive modelling of JET optimised shear discharges  

Energy Technology Data Exchange (ETDEWEB)

Transport analysis of high performance JET plasmas with optimised magnetic shear (OMS) has revealed many interesting features which can not be explained by the existing JET empirical transport model. TRANSP analysis shows that transport coefficients in OMS plasmas are often reduced in the plasma core to the level of ion neoclassical transport. TRANSP analysis and predictive modelling with JETTO show that this region of improved confinement appears near the plasma centre and then expands outwards in a way which does not follow either the evolution of the region with the negative magnetic shear or the propagation of the region with a large shear in plasma rotation. The best agreement with experiment has been achieved by using a transport model which combines the effect of a long wavelength decoupling due to small magnetic shear with its suppression by strong rotational shear. Predictive modelling of some of the characteristic JET OMS plasmas gives quite good agreement between such a model and the experimental data. (author)

Parail, V.; Baranov, Y.F.; Challis, C. [and others

1998-12-01

176

Modified Shear Box Test Apparatus for Measuring Shear Strength of Unsaturated Residual Soil  

Directory of Open Access Journals (Sweden)

Full Text Available Residual soils occur in most countries of the world but the greater areas and depths are normally found in tropical humid areas. Most of these soils exhibit high suctions for most of the year. The shear strength parameters, c’ and Φ’, of soil can be obtained using conventional shear strength tests. However the conventional shear strength test equipments would not be able to measure Φb value (change of shear strength to change in suction) without certain modification to them. This study describes the modifications that have been made to a standard shear box test apparatus to enable it to test soil samples in unsaturated conditions. The modifications include fabrication of an air pressure chamber, modifications of the shear box assembly inside the air pressure chamber, modification to the normal loading system, as well as additions of data acquisition devices to enhance the performance and simplify the usage of the modified shear box test apparatus.

Bujang B.K. Huat; Faisal H. Ali; S. Hashim

2005-01-01

177

Microstructural study of adiabatic shear band  

Science.gov (United States)

This article presents a study of the microstructural development of the adiabatic shear band in an HY-100 steel. The steel was deformed at a high strain rate by ballistic impact, and subsequent metallographic observations along with electron microscopy were performed. A number of white- etched shear bands were found near the perforated region, and three typical microstructural features of the adiabatic shear band were observed: elongated grain structure at the boundary between the shear band and matrix, fine equiaxed grain structure with high dislocation densities in the middle of the shear band, and relatively coarse-grained structure located between the above two structures. These microstructures might be formed in an extremely short time by the combined effects of the large temperature rise and the highly localized deformation. Since very complex phenomena might occur within the shear band, possible mechanisms, such as dynamic recovery and strain-induced dynamic phase transformation, are suggested to explain the micro- structural development of the adiabatic shear band.

Lee, Sunghak; Cho, Kyung-Mox; Lee, Chang Sun; Choo, Wung Yong

1993-10-01

178

Shear behaviour of laminated Douglas fir veneer.  

UK PubMed Central (United Kingdom)

The rolling shear and longitudinal shear behaviour of laminated Douglas fir veneers was studied using specimens with 15 layers of 2.5 mm veneers. The rolling shear specimens were constructed such that the 3 central veneers were cross-plies with grain angle oriented perpendicular to the long axis of the specimen. The other layers were orthogonal to the cross-plies. The longitudinal shear specimens had a LVL lay-up with the exception of a reinforcement layer of fiber-glass attached to the bottom face veneer. The fiber-glass layer prevented specimens from failing in bending/tension mode and ensured longitudinal shear failures. Specimens were subjected to static and cyclic loads in a "flatwise" three point bending configuration. It was found that the rolling shear failure mode exhibited a higher fatigue resistance than the longitudinal shear failure mode. A damage model that took the stress history into account was calibrated to the experimental data of each specimen type. Good agreement between model predictions and experimental results were obtained for both failure modes.

Norlin LP; Norlin CM; Lam F

1999-06-01

179

Quasi-3D Modeling of Shear Waves  

Science.gov (United States)

Shear waves were first addressed by Oltman-Shay et. al (1989). Since then, they have been studied intensively. Most of these studies are either based on linear stability analysis or direct simulation utilizing nonlinear shallow water equations. One reason that shear waves attract so much attention is that they are believed to be a plausible mechanism that could contribute to the mixing in the nearshore circulation modeling. On the other hand, Svendsen and Putrevu (1994) found that the 3D structure of currents will also introduce momentum mixing which is similar to the dispersion effect discovered by Taylor (1954), and which is at least one order larger than the turbulence mixing. In this work, we will utilize a quasi-3D nearshore circulation model SHORECIRC (Svendsen et. al, 2000) to simulate finite amplitude shear waves. Our purpose was to investigate how the 3D dispersion mixing and the lateral mixing provided by the shear waves affect each other. To achieve this, 2D and quasi-3D numerical experiments are carried out simultaneously. Our calculations showed that shear waves are more organized in the quasi-3D simulation than that in 2D simulation. We also found that under certain circumstances, the mixing provided by shear waves can be even stronger than that of the 3D dispersive mixing. As the shear waves grow, the 3D dispersive mixing decreases.

Zhao, Q.; Svendsen, I.

2001-12-01

180

IMAGE ANALYSIS FOR MODELLING SHEAR BEHAVIOUR  

Directory of Open Access Journals (Sweden)

Full Text Available Through laboratory research performed over the past ten years, many of the critical links between fracture characteristics and hydromechanical and mechanical behaviour have been made for individual fractures. One of the remaining challenges at the laboratory scale is to directly link fracture morphology of shear behaviour with changes in stress and shear direction. A series of laboratory experiments were performed on cement mortar replicas of a granite sample with a natural fracture perpendicular to the axis of the core. Results show that there is a strong relationship between the fracture's geometry and its mechanical behaviour under shear stress and the resulting damage. Image analysis, geostatistical, stereological and directional data techniques are applied in combination to experimental data. The results highlight the role of geometric characteristics of the fracture surfaces (surface roughness, size, shape, locations and orientations of asperities to be damaged) in shear behaviour. A notable improvement in shear understanding is that shear behaviour is controlled by the apparent dip in the shear direction of elementary facets forming the fracture.

Philippe Lopez; Joëlle Riss; Sylvie Gentier; Rock Flamand; Guy Archambault; Soizic Bouvet

2000-01-01

 
 
 
 
181

Shear instability in magnetized, collisional dusty plasmas  

Energy Technology Data Exchange (ETDEWEB)

The shear instability of magnetized, collisional dusty plasma is investigated in the present work. It is demonstrated that the relative drift between the charged dust and magnetised electrons and ions which give rise to the Hall effect is crucial to this instability. Although the nature of present shear instability is similar to the Kelvin-Helmholtz instability, the role of magnetic field in the present case is important in destabilising waves. The maximum growth rate of the instability is proportional only to the shear gradient and is independent of the ambient magnetic field strength. Most unstable wavenumber is a function of ambient dust parameters.

Pandey, B. P. [Department of Physics and Astronomy, Macquarie University, Sydney, New South Wales 2109 (Australia); Vladimirov, S. V.; Samarian, A. A. [School of Physics, University of Sydney, New South Wales 2006 (Australia)

2012-06-15

182

Sonic instabilities in supersonic shear flows  

International Nuclear Information System (INIS)

Using analytical methods the stability of a linear supersonic shear layer is re-examined. Two mechanisms working both for Kelvin-Helmholtz-type modes and sonic modes are responsible for instabilities caused by the shear: resonant interaction between modes and energy loss due to acoustic radiation of modes having negative energy. Which of these mechanisms is dominant sensitively depends on the density contrast between the shear layer and the surrounding medium. A close relation to the instability of accretion tori discovered by previous authors is found. (author).

1988-01-01

183

Bubbles in sheared two-dimensional foams  

CERN Document Server

Oscillatory shear on two-dimensional monodisperse liquid foams was performed. We show that the effect of the oscillatory shear is to cause the migration of bubbles which size is greater than that of a typical bubble of the foam. These so-called flaws move towards the periphery of the foam in a non random motion, thus realizing size segregation in a system which is by construction gravity insensitive. We also show that elongated cavities in the foam could be relaxed towards a more isotropic form with oscillatory shear, and we discuss the pertinent parameters of this relaxation.

Quilliet, C; Dollet, B; Berthier, L; Yekini, A

2005-01-01

184

Shear Dynamics in Bianchi I Cosmology  

CERN Document Server

We present the exact equation for evolution of Bianchi I cosmological model, considering a non-tilted perfect fluid in a matter dominated universe. We use the definition of shear tensor and later we prove it is consistent with the evolution equation for shear tensor obtained from Ricci identities and widely known in literature [3], [5], [9]. Our result is compared with the equation given by Ellis and van Elst in [3] and Tsagas, Challinor and Maartens [5]. We consider that it is important to clarify the notation used in [3], [5] related with the covariant derivative and the behavior of the shear tensor.

Caceres, Diego; Tejeiro, Juan M

2010-01-01

185

Shear Excitation of Confined Colloidal Suspensions  

CERN Document Server

We show that geometric confinement dramatically affects the shear-induced configurations of dense mono-disperse colloidal suspensions; a new structure emerges, where layers of particles buckle to stack in a more efficient packing. The volume fraction in the shear zone is controlled by a balance between the viscous stresses and the osmotic pressure of a contacting reservoir of unsheared particles. We present a model that accounts for our observations and helps elucidate the complex interplay between particle packing and shear stress for confined suspensions.

Cohen, I; Weitz, D A; Cohen, Itai; Mason, Thomas G.; Weitz, David A.

2004-01-01

186

Shear viscosity of liquid mixtures: Mass dependence  

International Nuclear Information System (INIS)

Expressions for zeroth, second, and fourth sum rules of transverse stress autocorrelation function of two component fluid have been derived. These sum rules and Mori's memory function formalism have been used to study shear viscosity of Ar-Kr and isotopic mixtures. It has been found that theoretical result is in good agreement with the computer simulation result for the Ar-Kr mixture. The mass dependence of shear viscosity for different mole fraction shows that deviation from ideal linear model comes even from mass difference in two species of fluid mixture. At higher mass ratio shear viscosity of mixture is not explained by any of the emperical model. (author)

2002-01-01

187

Sonic instabilities in supersonic shear flows  

Energy Technology Data Exchange (ETDEWEB)

Using analytical methods the stability of a linear supersonic shear layer is re-examined. Two mechanisms working both for Kelvin-Helmholtz-type modes and sonic modes are responsible for instabilities caused by the shear: resonant interaction between modes and energy loss due to acoustic radiation of modes having negative energy. Which of these mechanisms is dominant sensitively depends on the density contrast between the shear layer and the surrounding medium. A close relation to the instability of accretion tori discovered by previous authors is found.

Glatzel, W.

1988-04-01

188

Method for shearing spent nuclear fuel assemblies  

International Nuclear Information System (INIS)

A method is disclosed for shearing spent nuclear fuel assemblies of the type wherein a plurality of long metal tubes packed with ceramic fuel are supported in a spaced apart relationship within an outer metal shell or shroud which provides structural support to the assembly. Spent nuclear fuel assemblies are first compacted in a stepwise manner between specially designed gag-compactors and then sheared into short segments amenable to chemical processing by shear blades contoured to mate with the compacted surface of the fuel assembly

1977-01-01

189

Piping shear lug stress analysis  

International Nuclear Information System (INIS)

Due to space limitations present in many of the current nuclear power plants, it is frequently necessary to apply restraints skewed to a piping system's axis in order to restrain the piping against hydraulic transient and seismic loads. In order to assuure that the restraints function as required, shear lugs are often used to eliminate relative motion between the pipe and the restraint. The design of these lugs must be such that the stresses induced in the pipe are in compliance with the criteria of the ASME Code. According to the Code, stresses may be determined by either a detailed stress analysis or by use of given simplified analysis procedures employing stress indices. At present, stress indices are not provided for lugs. It is the purpose of this paper, to present detailed stress analyses of the pipe-lug system and from them deduce expressions for the needed indices. The analyses are accomplished through use of three-dimensional finite-element modeling employing the computer program SAP IV. (Auth.).

1977-08-19

190

Shear effects on crystalline structures of poly(L-lactide)  

DEFF Research Database (Denmark)

The shearing effects of sheared polymer melts on their finally formed crystalline structures of poly(L-lactide) (PLLA) were investigated by means of small angle X-ray scattering (SAXS) and wide angle X-ray diffraction (WAXD). The results of WAXD prove that shear has no effects on the crystal structure of PLLA. The SAXS results demonstrate that both of the long period and the thickness of crystalline lamellae increase with rising shear rates when vertical to the shear direction, but remains constant when being parallel to the shear direction. The structural changes for samples prepared with different shear temperature or under the same shear strain but different shear rate were investigated. The mesophase of polymer melts and shearing effects on their pre-ordered phase turned out to be the key factor affecting the crystal structure of PLLA under different shearing conditions.

Xiao, Peitao; Li, Hongfei

2013-01-01

191

High pressure effects on the quality and preservation of cold-smoked dolphinfish (Coryphaena hippurus) fillets  

UK PubMed Central (United Kingdom)

Different high pressure treatments (200-400 MPa) were tested to establish the best processing conditions for cold-smoked fish fillets of dolphinfish (Coryphaena hippurus). The water holding capacity (WHC) decreased at 400 MPa, while the shear strength by Kramer cell and Warner Bratzler and colour (L*, a*, and b*) values rose at all the pressures applied; although in the case of the myotomes and myosepts the increase in shear strength was higher at 400 MPa, and the same was true for the a* and b* values. Lipid oxidation was prevented by the phenolic compounds from the smoking process. The best sensory attribute scores were achieved for cold-smoked dolphin fish pressurized at 300 MPa. During chilled storage the behaviour of WHC, shear strength, lipid oxidation, and colour in the sample pressurized at 300 MPa was quite stable, although sensory attributes declined over storage and fell off sharply after 65 d. Total volatile base levels rose over the storage period but did not exceed 35 mg TVBN/100 g. High pressure did not extend the shelf life, but it was able to diminish bacterial counts during early storage. Since pressurized products have achieved better acceptance than non pressurized ones, it could be utilised to obtain new products.

Go?mez-Estaca J; Go?mez-Guille?n MC; Montero P

2007-01-01

192

Quantitative shear wave magnetic resonance elastography: comparison to a dynamic shear material test.  

UK PubMed Central (United Kingdom)

Magnetic resonance elastography (MRE), a phase contrast MRI technique, images the propagation of applied mechanical waves in tissue, allowing shear stiffness to be quantified in vivo. This MRE technique has been validated with static mechanical compression tests. Dynamic mechanical analysis (DMA) may be a more appropriate comparison to MRE because it directly measures the shear modulus dynamically, while compression tests convert the measured elastic modulus to shear modulus with an assumed Poisson ratio. This study compared the shear stiffness estimated with various MRE inversion algorithms (i.e., manual calculation, local frequency estimate, phase gradient, direct inversion, and matched filter) to the dynamic mechanical test. The shear stiffness of five agarose gels with concentrations ranging from 1.5 to 3.5% were measured using MRE and DMA. The phase gradient inversion algorithm overestimated the shear modulus at higher concentrations (i.e., 3-3.5% agar), while the results from the other techniques correlated well with the dynamic mechanical test.

Ringleb SI; Chen Q; Lake DS; Manduca A; Ehman RL; An KN

2005-05-01

193

Jamming and shear for granular materials  

Science.gov (United States)

This paper describes a series of experiments which have explored systems of frictional disks that have been prepared near jamming and then subjected to shear strain. A key observation is that below a density (described by packing fraction, ?) of about ?J ~= 0.84, it is possible to prepare stress-free states, and then by applying shear, traverse states that are fragile (highly anisotropic), shear jammed, and then increasingly isotropic. The anisotropy of these states is a dominante feature in the shear jamming process, which differs from the Liu-Nagel scenario. The evolution of these states suggests that an activated process in the context of a force (or stress) ensemble characterizes the stress evolution during cyclic strain.

Behringer, R. P.; Dijksman, Joshua; Ren, Jie; Zhang, Jie; Majmudar, Trushant; Chakraborty, Bulbul; Bi, Daipeng; Tordesillas, Antoinette

2013-06-01

194

Recent progress in shear punch testing  

International Nuclear Information System (INIS)

The shear punch test was developed in response to the needs of the materials development community for small-scale mechanical properties tests. Such tests will be of great importance when a fusion neutron simulation device is built, since such a device is expected to have a limited irradiation volume. The shear punch test blanks a circular disk from a fixed sheet metal specimen, specifically a TEM disk. Load-displacement data generated during the test can be related to uniaxial tensile properties such as yield and ultimate strength. Shear punch and tensile tests were performed at room temperature on a number of unirradiated aluminum, copper, vanadium, and stainless steel alloys and on several irradiated aluminum alloys. Recent results discussed here suggest that the relationship between shear punch strength and tensile strength varies with alloy class, although the relationship determined for the unirradiated condition remains valid for the irradiated aluminum alloys

1994-01-01

195

Seismic Shears and Overturning Moments in Buildings.  

Science.gov (United States)

Seismic force distributions for simplified computation of shears and over-turning moment for preliminary design of buildings have been generated. A parameter study of the significant variables has been made to determine the applicability of the proposed d...

N. M. Newmark R. Smilowitz

1977-01-01

196

New laboratory direct shear test device  

Energy Technology Data Exchange (ETDEWEB)

A laboratory test device for measuring the load-deformation characteristics of NX-size rock samples in the direct shear mode has been designed and fabricated. The design, specification, operation, and sample preparation are described.

Chugh, Y.P.; Ober, S.

1985-07-01

197

Wall Shear Rates in Taylor Vortex Flow  

Directory of Open Access Journals (Sweden)

Full Text Available Wall shear rate and its axial and azimuthal components were evaluated in stable Taylor vortices. The measurements were carried out in a broad interval of Taylor numbers (52-725) and several gap width (R1/R2 = 0.5 – 0.8) by two three-segment electrodiffusion probes and three single probes flush mounted in the wall of the outer fixed cylinder. The axial distribution of wall shear rate components was obtained by sweeping the vortices along the probes using a slow axial flow. The experimental results were verified by CFD simulations. The knowledge of local wall shear rates and its fluctuations is of primordial interest for industrial applications like tangential filtration, membrane reactors and bioreactors containing shear sensitive cells.

V. Sobolik; T. Jirout; J. Havlica; M. Kristiawan

2011-01-01

198

Shear stress distribution due to shear and Rayleigh wave propagation at deep soil sites  

International Nuclear Information System (INIS)

Earthquake strong motion at ground surface may be described as the combined result of body (compression and shear) waves and surface waves. In the course of earthquake engineering site response analyses, it is usually assumed that surface motions are a result of vertically propagating body waves. In studies of liquefaction potential, it is assumed that soil shear strains are a result of vertically propagating shear waves. However, shear strains are also caused by surface Rayleigh waves and solutions to strains from each source are derived and compared in the paper, and the results for shear strain in terms of surface acceleration and wave length are presented in non-dimensional form. The results of this investigation show that the distribution of soil shear strain as a function of depth below the gound surface is different depending upon whether shear waves or Rayleigh waves are assumed to be the source of horizontal motions at the ground surface. It is shown that the shear strains derived from Rayleigh waves are greater near the surface but decrease faster with depth than the shear strains derived from vertically propagating shear waves. It is noted that the more rapid attenuation of shear strains with depth as predicted by Rayleigh wave theory is more consistent with observed cases of soil liquefaction which are usually limited to shallow depths, generally not in excess of 10 to 20 meters. On the contrary, vertical shear propagation theory predicts liquefaction occurring at loose sand sites at much greater depths. The differences are significant enough to influence the decision regarding liquefaction potential of a soil site.

1977-08-19

199

The role of shear in interferometry  

Energy Technology Data Exchange (ETDEWEB)

The shear in an interferometer system depends not only on the type of interferometer and its adjustment but also on how the interferometer is used. It is the important parameter that enters into measurements of spatial coherence, from which such quantities as stellar diameters can be derived, and of wavefronts by common-path interferometry. In association with the tilt, the shear determines where the fringes are localized, and its variation can give a scan of this localization.

Steel, W.H.

1981-01-01

200

Measurement of shear impedances of viscoelastic fluids  

Energy Technology Data Exchange (ETDEWEB)

Shear-wave reflection coefficients from a solid/fluid interface are derived for non-Newtonian fluids that can be described by Maxwell, Voigt, and power-law fluid models. Based on model calculations, we have identified the measurable effects on the reflection coefficients due to fluid non-Newtonian behavior. The models are used to interpret the viscosity data obtained by a technique based on shear impedance measurement.

Sheen, Shuh-Haw; Chien, Hual-Te; Raptis, A.C.

1996-12-31

 
 
 
 
201

Sheared-flow Modes in Toroidal Geometry  

Energy Technology Data Exchange (ETDEWEB)

Using a Fourier-Bessel representation for the fluctuating (turbulent) electrostatic potential, an equation governing the sheared-flow modes in toroidal geometry is derived from the gyrokinetic Poisson equation, where both the adiabatic and non-adiabatic responses of the electrons are taken into account. It is shown that the principal geometrical effect on sheared-flow modes of the electrostatic potential is due to the flux-surface average of 1/B, where B is the magnetic field strength.

J.L.V. Lewandowski; T.S. Hahm; W.W. Lee; Z. Lin

1999-10-01

202

Wrinkling of microcapsules in shear flow  

Energy Technology Data Exchange (ETDEWEB)

Elastic capsules can exhibit short wavelength wrinkling in external shear flow. We analyse this instability of the capsule shape and use the length scale separation between the capsule radius and the wrinkling wavelength to derive analytical results both for the threshold value of the shear rate and for the critical wavelength of the wrinkling. These results can be used to deduce elastic parameters from experiments. (letter to the editor)

Finken, R; Seifert, U [II. Institut fuer Theoretische Physik, Universitaet Stuttgart, 70550 Stuttgart (Germany)

2006-04-19

203

Magnetized stratified rotating shear waves.  

UK PubMed Central (United Kingdom)

We present a spectral linear analysis in terms of advected Fourier modes to describe the behavior of a fluid submitted to four constraints: shear (with rate S), rotation (with angular velocity ?), stratification, and magnetic field within the linear spectral theory or the shearing box model in astrophysics. As a consequence of the fact that the base flow must be a solution of the Euler-Boussinesq equations, only radial and/or vertical density gradients can be taken into account. Ertel's theorem no longer is valid to show the conservation of potential vorticity, in the presence of the Lorentz force, but a similar theorem can be applied to a potential magnetic induction: The scalar product of the density gradient by the magnetic field is a Lagrangian invariant for an inviscid and nondiffusive fluid. The linear system with a minimal number of solenoidal components, two for both velocity and magnetic disturbance fields, is eventually expressed as a four-component inhomogeneous linear differential system in which the buoyancy scalar is a combination of solenoidal components (variables) and the (constant) potential magnetic induction. We study the stability of such a system for both an infinite streamwise wavelength (k(1) = 0, axisymmetric disturbances) and a finite one (k(1) ? 0, nonaxisymmetric disturbances). In the former case (k(1) = 0), we recover and extend previous results characterizing the magnetorotational instability (MRI) for combined effects of radial and vertical magnetic fields and combined effects of radial and vertical density gradients. We derive an expression for the MRI growth rate in terms of the stratification strength, which indicates that purely radial stratification can inhibit the MRI instability, while purely vertical stratification cannot completely suppress the MRI instability. In the case of nonaxisymmetric disturbances (k(1) ? 0), we only consider the effect of vertical stratification, and we use Levinson's theorem to demonstrate the stability of the solution at infinite vertical wavelength (k(3) = 0): There is an oscillatory behavior for ? > 1+|K(2)/k(1)|, where ? = St is a dimensionless time and K(2) is the radial component of the wave vector at ? = 0. The model is suitable to describe instabilities leading to turbulence by the bypass mechanism that can be relevant for the analysis of magnetized stratified Keplerian disks with a purely azimuthal field. For initial isotropic conditions, the time evolution of the spectral density of total energy (kinetic + magnetic + potential) is considered. At k(3) = 0, the vertical motion is purely oscillatory, and the sum of the vertical (kinetic + magnetic) energy plus the potential energy does not evolve with time and remains equal to its initial value. The horizontal motion can induce a rapid transient growth provided K(2)/k(1)>>1. This rapid growth is due to the aperiodic velocity vortex mode that behaves like K(h)/k(h) where k(h)(?)=[k(1)(2) + (K(2) - k(1)?)(2)](1/2) and K(h) =k(h)(0). After the leading phase (? > K(2)/k(1)>>1), the horizontal magnetic energy and the horizontal kinetic energy exhibit a similar (oscillatory) behavior yielding a high level of total energy. The contribution to energies coming from the modes k(1) = 0 and k(3) = 0 is addressed by investigating the one-dimensional spectra for an initial Gaussian dense spectrum. For a magnetized Keplerian disk with a purely vertical field, it is found that an important contribution to magnetic and kinetic energies comes from the region near k(1) = 0. The limit at k(1) = 0 of the streamwise one-dimensional spectra of energies, or equivalently, the streamwise two-dimensional (2D) energy, is then computed. The comparison of the ratios of these 2D quantities with their three-dimensional counterparts provided by previous direct numerical simulations shows a quantitative agreement.

Salhi A; Lehner T; Godeferd F; Cambon C

2012-02-01

204

Shear Driven Aggregation in Latex Colloids  

Science.gov (United States)

Reynolds number is small in colloidal flow and therefore, colloidal volume fraction and Peclet number are important. AS the volume fraction and attractive coupling between particles increase, relaxation time and Weisenberg number become significant. Shear-induced aggregation of latex colloids is due to the interplay between the shear-induced formation and breakage of latex .particles. While particle size is limited by breakage, their number density increases with the shearing-time. Upon cessation of shear, the particles interconnect into an assembly held by grainy bonds. It results in increase in yield stress and dynamic modulus. A contact model enables aggregates maintaining their structures under low stress while being restructured under high stress. Modeling involves solution of Navier- Stokes equation with moving particles as boundary condition for the flow like using the Lattice Boltzmann approach or by using (accelerated) Stokesian Dynamics. Alternate approach is to model the fluid phase by soft repulsive particles with pair-wise noise and friction, known as dissipative particle dynamics (DPD). This method by construction produces full inertial hydrodynamics, but applying the correct fluid-particle boundary condition is non-trivial. Both particle to particle and particle to wall collisions can be considered using Johnson-Kendall- Roberts (JKR) analysis of collision dynamics of dissipative forces using a soft-sphere modeling technique. Our experimental work used emulsion polymerized latex that was subjected to steady and dynamic shear. Yield stress, dynamic modulus and relaxation time increased on shearing in conjunction with changes in aggregate size.

Ahuja, Suresh

2013-03-01

205

Shear induced structures in crystallizing cocoa butter  

Science.gov (United States)

Cocoa butter is the main structural component of chocolate and many cosmetics. It crystallizes in several polymorphs, called phases I to VI. We used Synchrotron X-ray diffraction to study the effect of shear on its crystallization. A previously unreported phase (phase X) was found and a crystallization path through phase IV under shear was observed. Samples were crystallized under shear from the melt in temperature controlled Couette cells, at final crystallization temperatures of 17.5^oC, 20^oC and 22.5^oC in Beamline X10A of NSLS. The formation of phase X was observed at low shear rates (90 s-1) and low crystallization temperature (17.5^oC), but was absent at high shear (720 s-1) and high temperature (20^oC). The d-spacing and melting point suggest that this new phase is a mixture rich on two of the three major components of cocoa butter. We also found that, contrary to previous reports, the transition from phase II to phase V can happen through the intermediate phase IV, at high shear rates and temperature.

Mazzanti, Gianfranco; Guthrie, Sarah E.; Sirota, Eric B.; Marangoni, Alejandro G.; Idziak, Stefan H. J.

2004-03-01

206

Edging shears comprising a gripping device  

UK PubMed Central (United Kingdom)

The invention relates to edging shears comprising an ergonomic gripping device (2), a grip body (11) connected to a housing (10) and provided with a grip part (110), and a pivoting lever (13) that can be pivoted in relation to the grip body (11) and is used to actuate a pivotable shear blade (33). The gripping device (2) is applied to the housing (10) such that the grip part (11) extends from a rear end of the edging shears (1) towards a front end, and the edging shears (1) can be gripped on the grip part (11) for use such that the centre of gravity (Z) of the edging shears (1) is beneath the grip part (110), the pivoting lever (13) is connected to the grip body (11) in a rear region in terms of the longitudinal extension of the grip part (110), by means of a pivoting axis (12), force is transmitted from the pivoting lever (13) to the pivotable shear blade (33) by means of at least one force transmission element to which a tensile load can be applied, especially a strip, a cable (51), a wire cable or the like, and/or the grip body (11) is pivotably applied to the housing (10) such that an angle of inclination can be varied between the grip part (110) and a cutting plane (S).

BERNHARD REH; NORBERT KEIM; PETER LAMELI; HUBERT ALEKER; REINER HAEUFELE; OTTMAR LOCHER; VINCENT REICHART; CHRISTOPH SCHIEDT

207

Electroviscous effects of simple electrolytes under shear  

CERN Multimedia

On the basis of a hydrodynamical model analogous to that in critical fluids, we investigate the influences of shear flow upon the electrostatic contribution to the viscosity of binary electrolyte solutions in the Debye-H\\"{u}ckel approximation. Within the linear-response theory, we reproduce the classical limiting law that the excess viscosity is proportional to the square root of the concentration of the electrolyte. We also extend this result for finite shear. An analytic expression of the anisotropic structure factor of the charge density under shear is obtained, and its deformation at large shear rates is discussed. A non-Newtonian effect caused by deformations of the ionic atmosphere is also elucidated for $\\tau_D\\dot{\\gamma}>1$. This finding concludes that the maximum shear stress that the ionic atmosphere can support is proportional to $\\lambda_D^{-3}$, where $\\dot{\\gamma}$, $\\lambda_D$ and $\\tau_D=\\lambda_D^2/D$ are, respectively, the shear rate, the Debye screening length and the Debye relaxation tim...

Wada, H

2005-01-01

208

Wind-shearing in gaseous protoplanetary disks  

CERN Multimedia

One of the first stages of planet formation is the growth of small planetesimals and their accumulation into large planetesimals and planetary embryos. This early stage occurs much before the dispersal of most of the gas from the protoplanetary disk. Due to their different aerodynamic properties, planetesimals of different sizes/shapes experience different drag forces from the gas at these stage. Such differential forces produce a wind-shearing effect between close by, different size planetesimals. For any two planetesimals, a wind-shearing radius can be considered, at which the differential acceleration due to the wind becomes greater than the mutual gravitational pull between the planetesimals. We find that the wind-shearing radius could be much smaller than the gravitational shearing radius by the Sun (the Hill radius), i.e. during the gas-phase of the disk wind-shearing could play a more important role than tidal perturbations by the Sun. Here we study the wind-shearing radii for planetesimal pairs of dif...

Perets, Hagai B

2010-01-01

209

Evolution of circular shear layers  

International Nuclear Information System (INIS)

The Kelvin-Helmholtz instability is a generic pathway for the formation of coherent vortical structures in quasi-neutral and non-neutral plasmas, as well as in ordinary fluids. Both plasma and fluid experiments have demonstrated rich bifurcation sequences accompanied by topological changes in the distribution of the coherent structures, in addition to various oscillating, quasiperiodic or chaotic states. The authors have performed both analytical and numerical studies which demonstrate that such transitions can be accurately described by reducing the system of slightly viscous, forced Navier-Stokes equations to a system of ordinary differential equations of few degrees of freedom. The simplest case studied so far in detail leads to an equation of the Landau type describing the saturation of the Kelvin-Helmholtz instability in terms of the amplitude A(?) of the most unstable mode, with ? a slow time scale. In this case the dynamical equation assumes the form ?A?= ?A + ?A2A*. The complex coefficients of this reduced equation are computed by numerical solution of appropriate eigenvalue problems. In conjunction with these analytical calculations, a highly accurate spectral code has been used to directly simulate the forced, circular shear flows. Both the analytical and the numerical results are in excellent agreement with fluid experiments and show the same qualitative behavior as the plasma experiments where a detailed quantitative comparison is difficult due to limitations in the experimental information. The two approaches supplement each other in predicting the transition to states of ever increasing complexity, even beyond regimes that have so far been experimentally accessible.

1994-01-01

210

Aging of a colloidal glass under a periodic shear.  

UK PubMed Central (United Kingdom)

The aging dynamics under a periodic shear of a concentrated suspension of saponite particles is measured. It is observed that the dynamics is fastened by the application of a moderate shear amplitude. Nevertheless, this acceleration does not affect the dynamics of the suspension when the shear is ceased. By applying a succession of shear of various amplitudes, we conclude that the dynamics of the suspension at a time t(w) after complete rejuvenation is independent of the shear history between times 0 and t(w) , as soon as the amplitude of the applied shear is smaller than the characteristic shear gamma(c) necessary to completely rejuvenate the suspension.

Kaloun S; Skouri M; Knaebel A; Münch JP; Hébraud P

2005-07-01

211

Aging of a colloidal glass under a periodic shear.  

Science.gov (United States)

The aging dynamics under a periodic shear of a concentrated suspension of saponite particles is measured. It is observed that the dynamics is fastened by the application of a moderate shear amplitude. Nevertheless, this acceleration does not affect the dynamics of the suspension when the shear is ceased. By applying a succession of shear of various amplitudes, we conclude that the dynamics of the suspension at a time t(w) after complete rejuvenation is independent of the shear history between times 0 and t(w) , as soon as the amplitude of the applied shear is smaller than the characteristic shear gamma(c) necessary to completely rejuvenate the suspension. PMID:16089955

Kaloun, Soulaimane; Skouri, Mohammed; Knaebel, Alexandra; Münch, Jean-Pierre; Hébraud, Pascal

2005-07-01

212

Shear blade cutting device with adjusting blade alignment compensator  

UK PubMed Central (United Kingdom)

Disclosed is a shear blade cutting apparatus. The apparatus includes a frame assembly having a pair of shear blades pivotally mounted thereto. Actuators are connected between the shear blades and the frame assemblies for moving the shear blades between open and closed positions in pincer-like fashion. The cutting apparatus includes compensator assemblies for adjusting the connection between the actuators and the frame assembly, thereby to adjust the position of the shear blades relative to each other.

HOWETH D FRANKLIN

213

Stability of Shear-Thickening and Shear-Thinning Fluids in Narrow Gap between Rotating Cylinders  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The effect of weak shear Thickening and shear thinning on the stability of the Taylor-Couette flow is explored for a Carreau-Bird fluid in the narrow-gap limit. The Galerkin projection method is used to derive a low-order dynamical system from the conservation of mass...

Nariman Ashrafi Khorasani; Habibollah KarimiHaghighi

214

Shear strength in one- and two-way slabs according to the critical shear crack theory  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Currently, there is no generally-accepted theory giving a physical explanation of the shear strength in one- and two-way slabs. Furthermore, for members without transverse reinforcement, shear strength is estimated in most codes of practice following empirical or semi-empirical approaches. In thi...

Muttoni, Aurelio; Fernández Ruiz, Miguel

215

Influence of Shear on Rotation Capacity of Reinforced Concrete Members Without Shear Reinforcement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The influence of shear on the rotation capacity of one-way slabs without shear reinforcement is investigated in this paper by means of an experimental study. The experimental program consisted of 11 slab strips 8400 mm (331 in.) long and 450 mm (17.7 in.) thick with a flexural reinforcement ratio of...

Vaz Rodrigues, Rui; Muttoni, Aurelio; Fernández Ruiz, Miguel

216

Direct measurement of shear strain in adherent vascular endothelial cells exposed to fluid shear stress.  

UK PubMed Central (United Kingdom)

Functional and morphological responses of endothelial cells (ECs) to fluid shear stress are thought to be mediated by several mechanosensitive molecules. However, how the force due to fluid shear stress applied to the apical surface of ECs is transmitted to the mechanosensors is poorly understood. In the present paper, we performed an analysis of an intracellular mechanical field by observation of the deformation behaviors of living ECs exposed to shear stress with a novel experimental method. Lateral images of human umbilical vein ECs before and after the onset of flow were obtained by confocal microscopy, and image correlation and finite element analysis were performed for quantitative analyses of subcellular strain due to shear stress. The shear strain of the cells changed from 1.06+/-1.09% (mean+/-SD) to 4.67+/-1.79% as the magnitude of the shear stress increased from 2 to 10 Pa. The nuclei of ECs also exhibited shear deformation, which was similar to that observed in cytoplasm, suggesting that nuclei transmit forces from apical to intracellular components, as well as cytoskeletons. The obtained strain-stress relation resulted in a mean shear modulus of 213 Pa for adherent ECs. These results provide a mechanical perspective on the investigation of flow-sensing mechanisms of ECs.

Ueki Y; Sakamoto N; Sato M

2010-03-01

217

Shear deformation effects in enzyme catalysis. Metal ion effect in the shear inactivation of urease.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The mechanism of the inactivation of the enzyme urease produced by subjecting its dilute solutions to hydrodynamic shear stresses in the range 0.5-2.5 Pa has been determined. By studying the kinetics of urease-catalyzed urea hydrolysis during application of hydrodynamic shear under varying chemical ...

Tirrell, M; Middleman, S

218

Comparison between the homogeneous-shear and the sliding-boundary methods to produce shear flow  

Energy Technology Data Exchange (ETDEWEB)

Recently, Liem, Brown, and Clarke [Phys. Rev. A 45, 3706 (1992)] have compared the results obtained from the homogeneous-shear and the sliding-boundary nonequilibrium molecular-dynamics methods to generate shear flow. Here the comparison is carried out by using a kinetic theory description.

Santos, A.; Garzo, V. (Departamento de Fisica, Universidad de Extremadura, E-06071 Badajoz (Spain)); Brey, J.J. (Area de Fisica Teorica, Universidad de Sevilla, E-41080 Sevilla (Spain))

1992-12-15

219

Calcite fabrics in experimental shear zones  

Science.gov (United States)

Cylindrical specimens of Tennessee sandstone, with dry crushed calcite along 35° precut surfaces, are deformed at 200-MPa confining pressure, from 25° to 910°C, and at a shear strain rate of 10-2 s-1. Under these conditions the inelastic deformations are contained within the calcite layer. Shear displacements range between 1.5 and 3.0 mm, with engineering shear strain ? < 5.7. The compacted gouge (about 0.5 mm thick) is deformed in simple shear with non-coaxial incremental stress/strain and finite strain axes. The shear strength of specimens decreases from 300 MPa at 25°C to 30 MPa at 910°C, and the sliding mode changes from stick slip to stable sliding between 250° and 400°C. At <250°C the calcite deforms primarily by cataclasis, with Riedel shears that transect matrix and porphyroclasts, and conspicuous microfractures and twin lamellae in the porphyroclasts. The sliding mode is unstable (stick slip), but stress drops decrease between 25° and 250°C by a factor of 6. Between 250° and 650°C, slip on r {10 1¯1} and twin gliding on e (01 1¯2) predominate and produce highly elongated porphyroclasts with strong dimensional and crystallographic orientations. Average axial ratios change from about 2 at ?250°C to as much as 16 at 650°C (? = 4.96); average apparent long axes increase two- to three-fold, but average nominal grain areas remain constant. It is shown that the grain shape fabrics fit very closely predicted fabrics based upon homogeneous simple shear. The c axes of the porphyroclasts are strongly oriented within 20° of the axis of finite maximum shortening and geometrically track the axis of shortening with increasing shear strain. The sliding mode is stable. At temperatures of 550°-600°C, recrystallization occurs, after shearing by slip. Mosaics of very fine grained neoblasts are produced, with axial ratios <2.0. At 805°-910°C, two populations of neoblasts occur in each of four specimens. The first consists of larger, conspicuously twinned neoblasts with a ghost structure that tracks the finite strains and a strong crystallographic fabric that geometrically tracks neither the incremental stress nor the finite strain. The second group of neoblasts are smaller, strain free, and more equant and exhibit a very scattered crystallographic orientation. Neglecting differences in shear strain and temperature, the size of the larger neoblasts D is inversely proportional to the differential stress ?, with D = 41?-1.42. These larger neoblasts are well developed at a shear strain of only 0.61 (910°C) with an axial ratio of 1.7. This ratio and the crystallographic fabric remain constant for shear strains of 3.25, 4.71, and 5.69. It would appear that these neoblasts are syntectonic and are continually reformed during the shearing. The smaller strain-free neoblasts are probably due to annealing late in each experiment.

Friedman, M.; Higgs, N. G.

220

Thermodynamics for a system under shear  

International Nuclear Information System (INIS)

A thermodynamics is introduced for fluids subjected to a constant shear. The theory is based primarily on the results of computer simulations using the technique of homogeneous shear nonequilibrium molecular dynamics applied to a system of 108 Lennard-Jones particles. It is supported qualitatively by the results of several authors for other systems. The shear rate ? enters explicitly into the description of the fluid: the equation of state is p = p(V,T,?) and thermodynamic equation is dE = TdS -pdV+zetad?, where zeta is a state function. Using the relations found previously to be valid for a wide range of ?: p = p0+p1?/sup 3/2/ and E = E0+E1?/sup 3/2/, the thermodynamics can be checked numerically for consistency and several consequences, such as stability criteria criteria, can be verified. The criteria indicate that phase changes are influenced by the shear rate when the system is subjected to the shear

1982-03-15

 
 
 
 
221

Shear-related fibrillogenesis of fibronectin.  

Science.gov (United States)

Abstract Biomechanical forces can induce the transformation of fibronectin (Fn) from its compact structure to an extended fibrillar state. Adsorption of plasma proteins onto metallic surfaces may also influence their conformation. We used a cone-plate rheometer to investigate the effect of shear and stainless steel on conformational changes of Fn. In control experiments, cones grafted once or twice with polyethylene glycol were used. Plasma Fn was added at concentrations of 50 or 100 ?g/ml to bovine serum albumin (BSA)- or Fn-coated plates and subsequently exposed to dynamic shear rates stepwise increasing from 50 to 5000 s-1 within 5 min and subsequently decreasing from 5000 to 50 s-1 within 5 min. The viscosity (mPa s) of Fn solutions was recorded over 10 min. Upon exposure to shear, the viscosity in the sample increased, suggesting conformational changes in Fn. Western blotting and densitometric analyses demonstrated that conformational changes of plasma Fn depended both on shear and protein concentration. However, there was no significant difference in fibril formation between BSA- or Fn-coated plates, suggesting that physical properties of stainless steel and biomechanical forces such as shear can affect the molecular structure of Fn. Our model may provide useful information of surface- and flow-induced alterations of plasma proteins. PMID:24030032

Nguyen, Huong T T; Huynh, Khon C; Scharf, Rüdiger E; Stoldt, Volker R

2013-11-01

222

Shear-wave reflections in southeast Wyoming  

Energy Technology Data Exchange (ETDEWEB)

M. A. Martin and T. L. Davis have interpreted shear-wave seismic reflection data across the Silo field of southeast Wyoming in terms of microfractures. The azimuthally polarized shear waves in the shallow section indicate microfractures oriented at N40/sup 0/W, and time delays between split shear waves within the productive Niobrara (at about 8000 ft depth) are believed to be indicators of the direction and intensity of fracturing in that zone. This section, however, includes about 6200 ft of Pierre Shale, which is well documented to be transversely isotropic. That characteristic is confirmed by an offset vertical seismic profile in the Silo field that shows strong shear-wave polarization in the vertical and horizontal planes. The coexistence of these two types of anisotropy may cause complications in shear-wave transmission, such as multiple splitting. Synthetic and real data demonstrate that under these circumstances reflections are complex events, even when rotated into the optimum polarization direction. However, converted wave recordings, that is P waves reflected as S waves, may be much simpler and much easier to interpret.

Cameron, J.

1988-03-01

223

Alignment of particles in sheared viscoelastic fluids.  

UK PubMed Central (United Kingdom)

We investigate the shear-induced structure formation of colloidal particles dissolved in non-Newtonian fluids by means of computer simulations. The two investigated visco-elastic fluids are a semi-dilute polymer solution and a worm-like micellar solution. Both shear-thinning fluids contain long flexible chains whose entanglements appear and disappear continually as a result of Brownian motion and the applied shear flow. To reach sufficiently large time and length scales in three-dimensional simulations with up to 96 spherical colloids, we employ the responsive particle dynamics simulation method of modeling each chain as a single soft Brownian particle with slowly evolving inter-particle degrees of freedom accounting for the entanglements. Parameters in the model are chosen such that the simulated rheological properties of the fluids, i.e., the storage and loss moduli and the shear viscosities, are in reasonable agreement with experimental values. Spherical colloids dispersed in both quiescent fluids mix homogeneously. Under shear flow, however, the colloids in the micellar solution align to form strings in the flow direction, whereas the colloids in the polymer solution remain randomly distributed. These observations agree with recent experimental studies of colloids in the bulk of these two liquids.

Santos de Oliveira IS; van den Noort A; Padding JT; den Otter WK; Briels WJ

2011-09-01

224

COMPUTATIONAL APPROACH TO PREDICT SOIL SHEAR STRENGTH  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents an artificial neural network technique to predict the shear strength parameters of medium compressibility soil, which influenced by basic properties of soil in unconsolidated undrained conditions. Obviously obtained the undisturbed samples of soil to determination of shear strength parameters is a tedious work. Commercial software’s MATLAB-7 was used for this study. Triaxial shear tests were conducted to obtain these parameters at different water contents and densities. The results were used to predict the strength parameters. A set of 198 experimental results were used to construct the ANN model out of which 120 for training , 39 for validation and 39 for testing or prediction of shear strength parameters ( Cohesion & Angle of internal friction) were used. The correlation between the basic properties and shear strength parameters were obtained from the trained neural network. For trained the feed forward ANN models: multilayer perceptrons and radial basis function neural network, followings parameters were considered as input data – the compaction energy, degree of saturation, dry density and C & ? were output parameter. The regression coefficient and MSEwere 0.94, 0.76 and 0.0642, 0.253 respectively. In addition, the experimental results were compared to MLPN and RBF networks predicted results. It was concluded that the performance of the multilayer perceptron feed forward neural network model with three hidden layers is better than radial basis function neural network model.

Rajeev Jain,; Dr. Pradeep Kumar Jain,; Dr. Sudhir Singh Bhadauria

2010-01-01

225

Delayed shear enhancement in mesoscale atmospheric dispersion  

Energy Technology Data Exchange (ETDEWEB)

Mesoscale atmospheric dispersion (MAD) is more complicated than smaller-scale dispersion because the mean wind field can no longer be considered steady or horizontally homogeneous over mesoscale time and space scales. Wind shear also plays a much more important role on the mesoscale: horizontal dispersion can be enhanced and often dominated by vertical wind shear on these scales through the interaction of horizontal differential advection and vertical mixing. Just over 30 years ago, Pasquill suggested that this interaction need not be simultaneous and that the combination of differential horizontal advection with delayed or subsequent vertical mixing could maintain effective horizontal diffusion in spite of temporal or spatial reductions in boundary-layer turbulence intensity. This two-step mechanism has not received much attention since then, but a recent analysis of observations from and numerical simulations of two mesoscale tracer experiments suggests that delayed shear enhancement can play an important role in MAD. This paper presents an overview of this analysis, with particular emphasis on the influence of resolvable vertical shear on MAD in these two case studies and the contributions made by delayed shear enhancement.

Moran, M.D. [Atmospheric Environment Service, Ontario (Canada); Pielke, R.A. [Colorado State Univ., Fort Collins, CO (United States)

1994-12-31

226

Stochastic parametric resonance in shear flows  

Directory of Open Access Journals (Sweden)

Full Text Available Time-periodic shear flows can give rise to Parametric Instability (PI), as in the case of the Mathieu equation (Stoker, 1950; Nayfeh and Mook, 1995). This mechanism results from a resonance between the oscillatory basic state and waves that are superimposed on it. Farrell and Ioannou (1996a, b) explain that PI occurs because the snap-shots of the velocity profile are subject to transient growth. If the flows were purely steady the transient growth would subside and not have any long lasting effect. However, the coupling between transient growth and the time variation of the basic state create PI. Mathematically, transient growth, and therefore PI, are due to the nonorthogonal eigenspace in the linearized system. Poulin et al. (2003) studied a time-periodic barotropic shear flow that exhibited PI, and thereby produced mixing at the interface between Potential Vorticity (PV) fronts. The instability led to the formation of vortices that were stretched. A later study of an oscillatory current in the Cape Cod Bay illustrated that PI can occur in realistic shear flows (Poulin and Flierl, 2005). These studies assumed that the basic state was periodic with a constant frequency and amplitude. In this work we study a shear flow similar to that found in Poulin et al. (2003), but now where the magnitude of vorticity is a stochastic variable. We determine that in the case of stochastic shear flows the transient growth of perturbations of the snapshots of the basic state still generate PI.

F. J. Poulin; M. Scott

2005-01-01

227

High-shear-rate capillary viscometer for inkjet inks  

Energy Technology Data Exchange (ETDEWEB)

A capillary viscometer developed to measure the apparent shear viscosity of inkjet inks at high apparent shear rates encountered during inkjet printing is described. By using the Weissenberg-Rabinowitsch equation, true shear viscosity versus true shear rate is obtained. The device is comprised of a constant-flow generator, a static pressure monitoring device, a high precision submillimeter capillary die, and a high stiffness flow path. The system, which is calibrated using standard Newtonian low-viscosity silicone oil, can be easily operated and maintained. Results for measurement of the shear-rate-dependent viscosity of carbon-black pigmented water-based inkjet inks at shear rates up to 2x10{sup 5} s{sup -1} are discussed. The Cross model was found to closely fit the experimental data. Inkjet ink samples with similar low-shear-rate viscosities exhibited significantly different shear viscosities at high shear rates depending on particle loading.

Wang Xi [FUJIFILM Dimatix, Inc., Lebanon, New Hampshire 03766 (United States); Carr, Wallace W.; Bucknall, David G. [School of Polymer, Textile, and Fiber Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Morris, Jeffrey F. [Department of Chemical Engineering and Benjamin Levich Institute for Physico-Chemical Hydrodynamics, City College of New York, New York, New York 10031 (United States)

2010-06-15

228

Relation between ordering and shear thinning in colloidal suspensions.  

UK PubMed Central (United Kingdom)

Colloidal suspensions exhibit shear thinning and shear thickening. The most common interpretation of these phenomena identifies layering of the fluid perpendicular to the shear gradient as the driver for the observed behavior. However, studies of the particle configurations associated with shear thinning and thickening cast doubt on that conclusion and leave unsettled whether these nonequilibrium phenomena are caused primarily by correlated particle motions or by changes in particle packing structure. We report the results of stokesian dynamics simulations of suspensions of hard spheres that illuminate the relation among the suspension viscosity, shear rate, and particle configuration. Using a recently introduced sampling technique for nonequilibrium systems, we show that shear thinning can be decoupled from layering, thereby eliminating layering as the driver for shear thinning. In contrast, we find that there is a strong correlation between shear thinning and a two-particle measure of the shear stress. Our results are consistent with a recent experimental study.

Xu X; Rice SA; Dinner AR

2013-03-01

229

High-shear-rate capillary viscometer for inkjet inks  

International Nuclear Information System (INIS)

[en] A capillary viscometer developed to measure the apparent shear viscosity of inkjet inks at high apparent shear rates encountered during inkjet printing is described. By using the Weissenberg-Rabinowitsch equation, true shear viscosity versus true shear rate is obtained. The device is comprised of a constant-flow generator, a static pressure monitoring device, a high precision submillimeter capillary die, and a high stiffness flow path. The system, which is calibrated using standard Newtonian low-viscosity silicone oil, can be easily operated and maintained. Results for measurement of the shear-rate-dependent viscosity of carbon-black pigmented water-based inkjet inks at shear rates up to 2x105 s-1 are discussed. The Cross model was found to closely fit the experimental data. Inkjet ink samples with similar low-shear-rate viscosities exhibited significantly different shear viscosities at high shear rates depending on particle loading.

2010-01-01

230

Role of magnetic field shear in solar flares  

International Nuclear Information System (INIS)

Observational results and their physical implications on magnetic field shear in relation to flares are presented. The observed character of magnetic shear and its involvement in the buildup and release of flare energy are reviewed. It is pointed out that the magnetic field in active regions can become sheared by several processes, including shear flow in the photosphere, flux emergence, magnetic reconnection, and flux submergence. Modeling studies of the buildup of stored magnetic energy by shearing are reported which show ample energy storage for flares. Observational evidence is presented that flares are triggered when the field shear reaches a critical degree, in qualitative agreement with some theoretical analyses of sheared force-free fields. Finally, a scenario is outlined for the class of flares resulting from large-scale magnetic shear the overall instability driving the energy release results from positive feedback between reconnection and eruption of the sheared field. 28 references.

1984-01-01

231

Transversely Compressed- and Restrained Shear Joints  

DEFF Research Database (Denmark)

Anchorage of FRP strengthening systems where the deformation perpendicular to the FRP material is restrained or a compressive force is applied on the strengthening, seems to provide ductility, increased utilization of the FRP and failure modes which can be controlled through the anchorage method. This paper presents theoretical model which can predict the response of transversely compressed and restrained single- and double lap shear joints. The interface material model is based on a cohesive law in the shear-slip plane with a descending branch and a uniform frictional stress added due to the friction in the crack, emanating from the transverse pressure or restraint. The theoretical model is compared with experimental results from transversely compressed single- and double shear joints. Also theoretical predictions of a mechanical integrated sleeve-wedge anchorage load capacity are carried out and compared with tests. It is seen that the theory correlates well with the experimental results.

Schmidt, Jacob Wittrup; Hansen, Christian Skodborg

2013-01-01

232

Derivative moments in stationary homogeneous shear turbulence  

CERN Multimedia

A statistically stationary and nearly homogeneous turbulent shear flow is established by an additional volume forcing in combination with stress-free boundary conditions in the shear direction. Both turbulent energy and enstrophy are stationary to a much better approximation than in previous simulations that use remeshing. The temporal fluctuations decrease with increasing Reynolds number. Energy spectra and shear-stress cospectra show that local isotropy is satisfactorily obeyed at the level of second-order moments. However, derivative moments of high-order up to n=7 yield increasing moments for n>=4 for the spanwise vorticity and the transverse derivative of the streamwise velocity in the range of Taylor Reynolds numbers 59

Schumacher, J

2001-01-01

233

Spiral morphology and galactic shear rate  

CERN Multimedia

Spiral galaxies are observed to exhibit a range of morphologies, in particular in the shape of spiral arms. A key diagnostic parameter is the pitch angle, which describes how tightly wound the spiral arms are. Observationally and analytically, a correlation between pitch angle and galactic shear rate has been detected. For the first time, we perform a suite of N-body simulations to calculate and compare the pitch angles of both individual density waves and overall spiral structure by use of two independent techniques. We find that higher galactic shear rates produce more tightly wound spiral arms, both in individual mode patterns (density waves) and in the overall density enhancement. Although the mode pattern pitch angles by construction remain constant with time, the overall logarithmic spiral arm winds over time, which is consistent with both the observational scatter in pitch angle versus shear seen from observations, and the recent idea that multiple mode patterns may interfere with each other to create ...

Grand, Robert J J; Cropper, Mark

2012-01-01

234

Bounds on Surface Stress Driven Shear Flow  

CERN Multimedia

The background method is adapted to derive rigorous limits on surface speeds and bulk energy dissipation for shear stress driven flow in two and three dimensional channels. By-products of the analysis are nonlinear energy stability results for plane Couette flow with a shear stress boundary condition: when the applied stress is gauged by a dimensionless Grashoff number $Gr$, the critical $Gr$ for energy stability is 139.5 in two dimensions, and 51.73 in three dimensions. We derive upper bounds on the friction (a.k.a. dissipation) coefficient $C_f = \\tau/\\bar{u}^2$, where $\\tau$ is the applied shear stress and $\\bar{u}$ is the mean velocity of the fluid at the surface, for flows at higher $Gr$ including developed turbulence: $C_f le 1/32$ in two dimensions and $C_f \\le 1/8$ in three dimensions. This analysis rigorously justifies previously computed numerical estimates.

Hagstrom, George I

2013-01-01

235

APPLICATION OF SHEAR FLOW STRESS TO CHONDROCYTES  

UK PubMed Central (United Kingdom)

A bioreactor and method are provided for application of shear flow stress of about 1 to about 100 dynes/cm2 to cultured mammalian cells used for production of artificial cartilage. The bioreactor can be a circulating flow system (16) containing a media reservoir (9), a pump (10), a growth chamber (11) containing a substrate such as a monolayer supporting surface or a 3-dimensional scaffold, and tubing (12). Shear flow stress can be applied by growing a chondrocyte monolayer on the surface of a rotating drum or rotating disc immersed in liquid growth medium, by growing a chondrocyte monolayer on static plates past which a liquid growth medium is pumped, or by establishing chondrocytes in a 3-dimensional scafold and pumping liquid growth medium through the scaffold. Application of flow shear stress increases the ratio of type II to type I cartilage produced by cultured chondrocytes, and enhances maintenance of chondrocyte phenotype.

SELIKTAR Dror; DUNKELMAN Noushin; PETERSON Alvin E.; SCHREIBER Rhonda E.; WILLOUGHBY Jane; NAUGHTON Gail K.

236

Crystallization in a sheared colloidal suspension.  

UK PubMed Central (United Kingdom)

We study numerically the crystallization process in a supersaturated suspension of repulsive colloidal particles driven by simple shear flow. The effect of the shear flow on crystallization is two-fold: while it suppresses the initial nucleation, once a large enough critical nucleus has formed its growth is enhanced by the shear flow. Combining both effects implies an optimal strain rate at which the overall crystallization rate has a maximum. To gain insight into the underlying mechanisms, we employ a discrete state model describing the transitions between the local structural configurations around single particles. We observe a time-scale separation between these transitions and the overall progress of the crystallization allowing for an effective Markovian description. By using this model, we demonstrate that the suppression of nucleation is due to the inhibition of a pre-structured liquid.

Lander B; Seifert U; Speck T

2013-06-01

237

METHOD FOR MAKING A SHEAR BLADE  

UK PubMed Central (United Kingdom)

A shear blade assembly (10) on, for example, a tree harvester (12) has first and second blade portions (14, 16) which are urged into opposite portions of a tree circumference to cut the tree. A desirable shape of the blade assembly (10) is a concave configuration which minimizes tree damage and efficiently distributes loads through the shear blade assembly (10). An improved method for making the concave shear blade assembly (10) includes cutting blade surfaces (42, 44) on a blank (30) and leaving a web (50) between the surfaces (42, 44), then depressing the blank (30) to form the desired shape and dividing the blank (30) along the web (50) to form the first and second blade portions (14, 16). Making the surfaces (42, 44) before shaping and dividing the blade portions (14, 16) overcomes problems stemming from distortion of blades which are cut along a curvature following the step of obtaining the desired shape in the blade assembly (10).

WIRT L; WEBB A

238

On shear rheology of gel propellants  

Energy Technology Data Exchange (ETDEWEB)

Selected fuel, oxidizer and simulant gels were prepared and rheologically characterized using a rotational rheometer. For fuel gelation both organic and inorganic gellants were utilized, whereas oxidizers and simulants were gelled with addition of silica and polysaccharides, respectively. The generalized Herschel-Bulkley constitutive model was found to most adequately represent the gels studied. Hydrazine-based fuels, gelled with polysaccharides, were characterized as shear-thinning pseudoplastic fluids with low shear yield stress, whereas inhibited red-fuming nitric acid (IRFNA) and hydrogen peroxide oxidizers, gelled with silica, were characterized as yield thixotropic fluids with significant shear yield stress. Creep tests were conducted on two rheological types of gels with different gellant content and the results were fitted by Burgers-Kelvin viscoelastic constitutive model. The effect of temperature on the rheological properties of gel propellant simulants was also investigated. A general rheological classification of gel propellants and simulants is proposed. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Rahimi, Shai; Peretz, Arie [RAFAEL, MANOR Propulsion and Explosive Systems Division, Haifa (Israel); Natan, Benveniste [Faculty of Aerospace Engineering, Technion - Israel Institute of Technology, Haifa (Israel)

2007-04-15

239

Shears for picking-up fruits  

UK PubMed Central (United Kingdom)

A shears for picking-up fruits, consisting of an upper arc-shaped blade and its holder, a lower arc-shaped blade and its holder, is characterized in that the holder of the upper arc-shaped blade is provided with a barreled spring gear and a connecting lock carriage with a fruit holding net fixed on. The utility model has the advantages of a smart and reasonable design, a simple structure and a convenient usage. Farmers can use the shears to pick off what they want intact and without any damage with labor and time saved. In a word, as an ideal shears for picking-up fruits, the utility model can complete the mission of fruit picking and meet the requirements of farmers.

ZHUANG SHENGJUN

240

Turbulent shear instability of accretion disks  

Energy Technology Data Exchange (ETDEWEB)

The question of whether disks with a Keplerian rotation law can be turbulized is investigated. A regime or turbulent Couette flow between rotating coaxial cylinders is described in terms of the semiempirical Rott model of well-developed anisotropic turbulence. In this model the turbulence is characterized by two different relaxation time scales: the time required to isotropize the turbulent pulsations, and the damping time. For an inviscid fluid (large Reynolds number), turbulent flow can develop only for sufficiently large shear deformations Vertical BarpartialW(r)/rVertical Bar (W is the angular rotational velocity), not for all deformations. An estimate for the parameters of the turbulized Keplerian disk suggests a criterion for testing whether the shear turbulization mechanism can operate: if disks exist which have become turbulized through unstable stratification of the medium and which are characterized by a decidedly subsonic turbulization regime, then the mechanism of shear instability through turbulization cannot operate.

Iroshnikov, R.S.

1980-09-01

 
 
 
 
241

Shear Viscosity of a Hot Pion Gas  

CERN Multimedia

The shear viscosity of an interacting pion gas is studied using the Kubo formalism as a microscopic description of thermal systems close to global equilibrium. We implement the skeleton expansion in order to approximate the retarded correlator of the viscous part of the energy-momentum tensor. After exploring this in $\\phi^4$ theory we show how the skeleton expansion can be consistently applied to pions in chiral perturbation theory. The shear viscosity $\\eta$ is determined by the spectral width, or equivalently, the mean free path of pions in the heat bath. We derive a new analytical result for the mean free path which is well-conditioned for numerical evaluation and discuss the temperature and pion-mass dependence of the mean free path and the shear viscosity. The ratio $\\eta/s$ of the interacting pion gas exceeds the lower bound $1/4\\pi$ from AdS/CFT correspondence.

Lang, Robert; Weise, Wolfram

2012-01-01

242

Phase separating binary fluids under oscillatory shear  

CERN Multimedia

We apply lattice Boltzmann methods to study the segregation of binary fluid mixtures under oscillatory shear flow in two dimensions. The algorithm allows to simulate systems whose dynamics is described by the Navier-Stokes and the convection-diffusion equations. The interplay between several time scales produces a rich and complex phenomenology. We investigate the effects of different oscillation frequencies and viscosities on the morphology of the phase separating domains. We find that at high frequencies the evolution is almost isotropic with growth exponents 2/3 and 1/3 in the inertial (low viscosity) and diffusive (high viscosity) regimes, respectively. When the period of the applied shear flow becomes of the same order of the relaxation time $T_R$ of the shear velocity profile, anisotropic effects are clearly observable. In correspondence with non-linear patterns for the velocity profiles, we find configurations where lamellar order close to the walls coexists with isotropic domains in the middle of the ...

Xu, A; Lamura, A; Xu, Aiguo

2003-01-01

243

Viscoelastic Phase Separation in Shear Flow  

CERN Multimedia

We investigate viscoelastic phase separation in polymer solutions under shear numerically using a time-dependent Ginzburg-Landau model. The gross variables in our model are the polymer volume fraction and a conformation tensor. The latter represents chain deformations and relaxes slowly on the rheological time giving rise to a large viscoelastic stress. The polymer and the solvent obey two-fluid dynamics in which the viscoelastic stress acts asymmetrically on the polymer and, as a result, the stress and the diffusion are dynamically coupled. Above the coexistence curve and for shear rates larger than a crossover value, phase separation is induced incompletely and the solution behaves chaotically. Below the coexistence curve, sharp interfaces appear with increasing the quench depth and the solvent regions act as a lubricant. In these cases the composition heterogeneity causes more enhanced viscoelastic heterogeneity such that the macroscopic stress is decreased at fixed shear rate. We find steady two-phase sta...

Imaeda, T; Onuki, A; Imaeda, Tatsuhiro; Furukawa, Akira; Onuki, Akira

2003-01-01

244

Transport Physics in Reversed Shear Plasmas  

Energy Technology Data Exchange (ETDEWEB)

Reversed magnetic shear is considered a good candidate for improving the tokamak concept because it has the potential to stabilize MHD instabilities and reduce particle and energy transport. With reduced transport the high pressure gradient would generate a strong off-axis bootstrap current and could sustain a hollow current density profile. Such a combination of favorable conditions could lead to an attractive steady-state tokamak configuration. Indeed, a new tokamak confinement regime with reversed magnetic shear has been observed on the Tokamak Fusion Test Reactor (TFTR) where the particle, momentum, and ion thermal diffusivities drop precipitously, by over an order of magnitude. The particle diffusivity drops to the neoclassical level and the ion thermal diffusivity drops to much less than the neoclassical value in the region with reversed shear. This enhanced reversed shear (ERS) confinement mode is characterized by an abrupt transition with a large rate of rise of the density in the reversed shear region during neutral beam injection, resulting in nearly a factor of three increase in the central density to 1.2 X 10(exp 20) cube m. At the same time the density fluctuation level in the reversed shear region dramatically decreases. The ion and electron temperatures, which are about 20 keV and 7 keV respectively, change little during the ERS mode. The transport and transition into and out of the ERS mode have been studied on TFTR with plasma currents in the range 0.9-2.2 MA, with a toroidal magnetic field of 2.7-4.6 T, and the radius of the q(r) minimum, q{sub min}, has been varied from r/a = 0.35 to 0.55. Toroidal field and co/counter neutral beam injection toroidal rotation variations have been used to elucidate the underlying physics of the transition mechanism and power threshold of the ERS mode.

Levinton, F.M.; Batha, S.H. [Fusion Physics and Technology, Inc., Torrance, CA (United States); Beer, M.A.; Bell, M.G.; Budny, R.V.; Efthimion, P.C.; Mazzucato, E.; Nazikian, R.; Park, H.K.; Ramsey, A.T.; Schmidt, G.L.; Scott, S.D.; Synakowski, E.J.; Taylor, G.; Von Goeler, S.; Zarnstorff, M.C. [Princeton University, NJ (United States). Plasma Physics Laboratory; Bush, C.E. [Oak Ridge National Lab., TN (United States)

1997-12-31

245

Combined shearing interferometer and hartmann wavefront sensor  

International Nuclear Information System (INIS)

[en] A sensitive wavefront sensor combining attributes of both a Hartmann type of wavefront sensor and an AC shearing interferometer type of wavefront sensor. An incident wavefront, the slope of which is to be detected, is focussed to first and second focal points at which first and second diffraction gratings are positioned to shear and modulate the wavefront, which then diverges therefrom. The diffraction patterns of the first and second gratings are positioned substantially orthogonal to each other to shear the wavefront in two directions to produce two dimensional wavefront slope data for the AC shearing interferometer portion of the wavefront sensor. First and second dividing optical systems are positioned in the two diverging wavefronts to divide the sheared wavefront into an array of subapertures and also to focus the wavefront in each subaperture to a focal point. A quadrant detector is provided for each subaperture to detect the position of the focal point therein, which provides a first indication, in the manner of a Hartmann wavefront sensor, of the local wavefront slope in each subaperture. The total radiation in each subaperture, as modulated by the diffraction grating, is also detected by the quadrant detector which produces a modulated output signal representative thereof, the phase of which relative to modulation by the diffraction grating provides a second indication of the local wavefront slope in each subaperture, in the manner of an AC shearing interferometer wavefront sensor. The data from both types of sensors is then combined by long term averaging thereof to provide an extremely sensitive wavefront sensor

1985-01-01

246

Energetic Particle Acceleration in Shear Layers  

International Nuclear Information System (INIS)

[en] A plasma velocity shear layer and/or a tangential flow discontinuity provide conditions allowing for energetic particle acceleration. We review such acceleration processes acting both in non-relativistic and in relativistic flows. In heliospheric conditions shear layers can provide particles with energies compatible with the observed values (from several keV up to MeV), while in relativistic extragalactic jets proton energies even in excess of 1019 eV can be obtained. Application of the discussed theory to particular astrophysical objects is severely limited by inadequate knowledge of local physical conditions. (author)

1999-01-01

247

Seismic behaviour of concrete shear walls  

International Nuclear Information System (INIS)

Concrete shear walls have an important contribution to building stiffness. So, it is necessary to know their behaviour under seismic loads. The ultimate behaviour of shear walls under dynamic loadings has been studied. The study includes: - A description of the non linear global model based on cyclic static tests. - Non linear time history calculations for various forcing functions. The comparison of linear and non linear results have shown important margins related to the ductility when the bandwidth of the forcing function is narrow and centred on the wall natural frequency.

1989-01-01

248

Shear-free normal cosmological models  

International Nuclear Information System (INIS)

Shear-free normal cosmological models are the perfect fluid solutions of Einstein's equations in which rotation and shear vanish, and which are not static [they were all found by A. Barnes, Gen. Relativ. Gravit. 4, 105 (1973)]. They are either spherically, plane, or hyperbolically symmetric. Their symmetries are discussed in various coordinate systems and related to the conformal group of the three-dimensional flat space. A coordinate representation is introduced which unites all three cases into a single two-parameter family. The limiting transitions to the Friedman--Lemaitre--Robertson--Walker (FLRW) models and to the Schwarzschild--de Sitter-like solutions are presented

1989-01-01

249

Shear-free normal cosmological models  

Energy Technology Data Exchange (ETDEWEB)

Shear-free normal cosmological models are the perfect fluid solutions of Einstein's equations in which rotation and shear vanish, and which are not static (they were all found by A. Barnes, Gen. Relativ. Gravit. 4, 105 (1973)). They are either spherically, plane, or hyperbolically symmetric. Their symmetries are discussed in various coordinate systems and related to the conformal group of the three-dimensional flat space. A coordinate representation is introduced which unites all three cases into a single two-parameter family. The limiting transitions to the Friedman--Lemaitre--Robertson--Walker (FLRW) models and to the Schwarzschild--de Sitter-like solutions are presented.

Krasin-acute-accentski, A.

1989-02-01

250

Seismic behavior of reinforced concrete shear walls  

International Nuclear Information System (INIS)

Reinforced concrete shear walls have an important contribution to building stiffness. So, it is necessary to know their behavior under seismic loads. The ultimate behavior study of shear walls subjected to dynamic loadings includes: - a description of the nonlinear global model based on cyclic static tests, - nonlinear time history calculations for various forcing functions. The comparison of linear and nonlinear results shows important margins related to the ductility when the bandwidth of the forcing function is narrow and centred on the wall natural frequency

1989-01-01

251

Shear viscosity of a unitary Fermi gas.  

UK PubMed Central (United Kingdom)

We present an ab initio determination of the shear viscosity ? of the unitary Fermi gas, based on finite temperature quantum Monte Carlo calculations and the Kubo linear-response formalism. We determine the temperature dependence of the shear viscosity-to-entropy density ratio ?/s. The minimum of ?/s appears to be located above the critical temperature for the superfluid-to-normal phase transition with the most probable value being (?/s)min?0.2?/k(B), which is close the Kovtun-Son-Starinets universal value ?/(4?k(B)).

Wlaz?owski G; Magierski P; Drut JE

2012-07-01

252

Shear viscosity of a unitary Fermi gas.  

Science.gov (United States)

We present an ab initio determination of the shear viscosity ? of the unitary Fermi gas, based on finite temperature quantum Monte Carlo calculations and the Kubo linear-response formalism. We determine the temperature dependence of the shear viscosity-to-entropy density ratio ?/s. The minimum of ?/s appears to be located above the critical temperature for the superfluid-to-normal phase transition with the most probable value being (?/s)min?0.2?/k(B), which is close the Kovtun-Son-Starinets universal value ?/(4?k(B)). PMID:23030136

Wlaz?owski, Gabriel; Magierski, Piotr; Drut, Joaquín E

2012-07-12

253

Shear Viscosity of a Unitary Fermi Gas  

CERN Document Server

We present the first ab initio determination of the shear viscosity eta of the Unitary Fermi Gas, based on finite temperature Quantum Monte Carlo calculations and the Kubo linear-response formalism. We determine the temperature dependence of the shear viscosity to entropy density ratio eta/s, The minimum of eta/s appears to be located above the critical temperature for the superfluid-to-normal phase transition with the most probable value being eta/s approx 0.11 hbar/kB, which almost saturates the Kovtun-Son-Starinets (KSS) universal value hbar/(4 pi kB).

Wlaz?owski, Gabriel; Drut, Joaquín E

2012-01-01

254

Velocity Profiles in Slowly Sheared Bubble Rafts  

CERN Multimedia

Measurements of average velocity profiles in a bubble raft subjected to slow, steady-shear demonstrate the coexistence between a flowing state and a jammed state similar to that observed for three-dimensional foams and emulsions [Coussot {\\it et al,}, Phys. Rev. Lett. {\\bf 88}, 218301 (2002)]. For sufficiently slow shear, the flow is generated by nonlinear topological rearrangements. We report on the connection between this short-time motion of the bubbles and the long-time averages. We find that a smooth, average velocity is reached after averaging over only a relatively few number of rearrangement events.

Lauridsen, J; Dennin, M; Lauridsen, John; Chanan, Greg; Dennin, Michael

2004-01-01

255

[Allergic rhinosinusitis by Curvularia inaequalis (Shear) Boedijn].  

UK PubMed Central (United Kingdom)

Curvularia inaequalis (Shear) Boedijn is a fungus dematiaceo, saprophyte and plant pathogen found mainly in tropical and subtropical areas, associated with various organic substrates. Rarely been identified in systemic infections, skin and there is only one report of allergic rhinosinusitis described above. A case of allergic fungal rhinosinusitis by Curvularia inaequalis (Shear) Boedijn in which diagnosis was considered the signs and symptoms, sinus CT and cultivation of mucin.The patient was treated with endoscopic surgical toilet, plus use of inhaled steroids and itraconazole systemic. With good clinical response, is asymptomatic at one year.

Cruz R; Barthel E; Espinoza J

2013-06-01

256

Rate-dependent shear bands in a shear-transformation-zone model of amorphous solids.  

UK PubMed Central (United Kingdom)

We use shear transformation zone (STZ) theory to develop a deformation map for amorphous solids as a function of the imposed shear rate and initial material preparation. The STZ formulation incorporates recent simulation results [T. K. Haxton and A. J. Liu, Phys. Rev. Lett. 99, 195701 (2007)] showing that the steady state effective temperature is rate dependent. The resulting model predicts a wide range of deformation behavior as a function of the initial conditions, including homogeneous deformation, broad shear bands, extremely thin shear bands, and the onset of material failure. In particular, the STZ model predicts homogeneous deformation for shorter quench times and lower strain rates, and inhomogeneous deformation for longer quench times and higher strain rates. The location of the transition between homogeneous and inhomogeneous flow on the deformation map is determined in part by the steady state effective temperature, which is likely material dependent. This model also suggests that material failure occurs due to a runaway feedback between shear heating and the local disorder, and provides an explanation for the thickness of shear bands near the onset of material failure. We find that this model, which resolves dynamics within a sheared material interface, predicts that the stress weakens with strain much more rapidly than a similar model which uses a single state variable to specify internal dynamics on the interface.

Manning ML; Daub EG; Langer JS; Carlson JM

2009-01-01

257

Growth rate, body composition, and meat tenderness in early vs. traditionally weaned beef calves.  

UK PubMed Central (United Kingdom)

One hundred forty spring-born Angus x Gelbvieh and purebred Angus steers were selected for study as early weaned (EW; average age at weaning = 90 +/- 30 d) or traditionally weaned (TW; average age at weaning = 174 +/- 37 d) steers that were non-implanted or implanted (Synovex-S, Fort Dodge Animal Health, Overland Park, KS). Initially, steers were sorted by age, sire, and farm, and then allotted randomly in a 2 x 2 factorial arrangement of treatments of EW implanted (EWI), EW nonimplanted (EWN), TW implanted (TWI), or TW nonimplanted (TWN). Ultrasound measurements (US) of LM area (LMA), 12th rib fat thickness (US-BF), and marbling (US-M) were collected every 28 d during the time that steers were on feed. At 202 d of age, EW calves had larger US-LMA, US-BF, and BW than TW calves (37.9 vs. 32.3 cm2, 0.38 vs. 0.26 cm, and 271.6 vs. 218.9 kg, respectively; P < 0.001). At slaughter, EW calves had heavier HCW (290.4 vs. 279.7 kg, respectively; P < 0.05) and greater USDA marbling scores (51.25 vs. 46.26, respectively; P < 0.05) than TW calves; more EW steers graded USDA Choice or greater (P = 0.05). However, no differences were detected in BW (P = 0.15), LMA (P = 0.39), BF (P = 0.45), or liver abscess scores (P = 0.41). Twenty-four implanted steers were selected from the original group of 140 and sorted into two slaughter groups of 12. Twelve implanted steers from each weaning group, matched in slaughter BW but differing in age, were subsampled at slaughter to assess the effect of weaning age and chronological age on muscle tenderness. Younger animals had lower Warner-Bratzler shear force values (P < 0.001) than older calves after 14 d of postmortem aging; however, no differences were found in tenderness after 21 d of aging. Furthermore, there was greater variance (P < 0.001) in Warner-Bratzler shear force values among younger, EW steers vs. older, TW steers. These data provide evidence that early weaning of beef calves may be used as a tool to more effectively manage the cow-calf production system without compromising the quality of the offspring.

Meyer DL; Kerley MS; Walker EL; Keisler DH; Pierce VL; Schmidt TB; Stahl CA; Linville ML; Berg EP

2005-12-01

258

Effect of grazing and dietary protein on eating quality of Podolian beef.  

UK PubMed Central (United Kingdom)

Twenty-four young Podolian bulls were used to evaluate the effect of rearing system (extensive vs. intensive) in relation to postmortem aging (11 and 18 d) on the eating quality of the meat, with the diet of outdoor animals adjusted to the protein content of the indoor system (15% CP) or to the minimum protein content required for satisfactory growth (12% CP). At 415 ± 9.35 (SE) d of age, with a mean BW of 337.5 ± 16.51 (SE) kg, animals were allotted to 3 groups for the finishing period (172 d): 1) indoor group receiving a diet at 15% CP; 2) grazing animals receiving a diet at 15% CP of DM; and 3) grazing animals receiving a diet at 12% CP of DM. Longissimus dorsi lumborum muscle sampled from the right half and divided longitudinally into 2 sections was aged in vacuum packaging at 4°C until 11 and 18 d postmortem, respectively. Rearing system did not affect (P > 0.05) color, Warner-Bratzler shear force, texture profile, water-holding capacity, and most of the sensory attributes of the beef steaks. However, sensory tenderness was less in the meat from outdoor animals receiving a diet with 15% CP than in meat from outdoor animals receiving a diet with 12% CP or from the indoor group (P < 0.05). Meat aged 18 d showed decreased Warner-Bratzler shear force (P < 0.001), hardness (P < 0.001), cohesiveness (P < 0.05), springiness (P < 0.05), gumminess (P < 0.01), chewiness (P < 0.01), and thawing loss (P < 0.01) compared with meat aged for 11 d. Prolonging the aging time up to 18 d significantly increased b* (yellowness; P < 0.05), cooking losses (P < 0.001), and the intensity of all the texture sensory attributes, namely, juiciness and fatness (P < 0.05), chewiness, tenderness, and flavor (P < 0.01). Significant correlations were found between instrumental and sensory variables (range of r = -0.55 to -0.85, P < 0.05 to 0.001). Overall, in the present study, the rearing system did not markedly affect meat sensory and physical properties. Thus, we conclude that an outdoor system, even with reduced protein supplementation, may represent a valid farming system for local breeds in Mediterranean areas characterized by poor-quality pastures. However, an extended aging period is suggested to improve the main factor limiting the quality of this product, namely, reduced tenderness.

Marino R; Albenzio M; Caroprese M; Napolitano F; Santillo A; Braghieri A

2011-11-01

259

Effect of grazing and dietary protein on eating quality of Podolian beef.  

Science.gov (United States)

Twenty-four young Podolian bulls were used to evaluate the effect of rearing system (extensive vs. intensive) in relation to postmortem aging (11 and 18 d) on the eating quality of the meat, with the diet of outdoor animals adjusted to the protein content of the indoor system (15% CP) or to the minimum protein content required for satisfactory growth (12% CP). At 415 ± 9.35 (SE) d of age, with a mean BW of 337.5 ± 16.51 (SE) kg, animals were allotted to 3 groups for the finishing period (172 d): 1) indoor group receiving a diet at 15% CP; 2) grazing animals receiving a diet at 15% CP of DM; and 3) grazing animals receiving a diet at 12% CP of DM. Longissimus dorsi lumborum muscle sampled from the right half and divided longitudinally into 2 sections was aged in vacuum packaging at 4°C until 11 and 18 d postmortem, respectively. Rearing system did not affect (P > 0.05) color, Warner-Bratzler shear force, texture profile, water-holding capacity, and most of the sensory attributes of the beef steaks. However, sensory tenderness was less in the meat from outdoor animals receiving a diet with 15% CP than in meat from outdoor animals receiving a diet with 12% CP or from the indoor group (P < 0.05). Meat aged 18 d showed decreased Warner-Bratzler shear force (P < 0.001), hardness (P < 0.001), cohesiveness (P < 0.05), springiness (P < 0.05), gumminess (P < 0.01), chewiness (P < 0.01), and thawing loss (P < 0.01) compared with meat aged for 11 d. Prolonging the aging time up to 18 d significantly increased b* (yellowness; P < 0.05), cooking losses (P < 0.001), and the intensity of all the texture sensory attributes, namely, juiciness and fatness (P < 0.05), chewiness, tenderness, and flavor (P < 0.01). Significant correlations were found between instrumental and sensory variables (range of r = -0.55 to -0.85, P < 0.05 to 0.001). Overall, in the present study, the rearing system did not markedly affect meat sensory and physical properties. Thus, we conclude that an outdoor system, even with reduced protein supplementation, may represent a valid farming system for local breeds in Mediterranean areas characterized by poor-quality pastures. However, an extended aging period is suggested to improve the main factor limiting the quality of this product, namely, reduced tenderness. PMID:21705638

Marino, R; Albenzio, M; Caroprese, M; Napolitano, F; Santillo, A; Braghieri, A

2011-06-24

260

A genome scan for meat quality traits in Nelore beef cattle.  

UK PubMed Central (United Kingdom)

Meat quality traits are economically important because they impact consumers' acceptance which, in turn, influences the demand for beef. However, selection to improve meat quality is limited by the small numbers of animals on which meat tenderness can be evaluated due to the cost of performing shear force analysis and the resultant damage to the carcass. Genome wide-association studies (GWAS) for Warner-Bratzler shear force (WBSF) measured at different times of meat aging, backfat thickness (BFT), ribeye muscle area (REA), scanning parameters (Lightness (L*), redness (a*) and yellowness (b*) to ascertain color characteristics of meat and fat, water-holding capacity (WHC), cooking loss (CL) and muscle pH, were conducted using genotype data from the Illumina BovineHD BeadChip array to identify quantitative trait loci (QTL) in all phenotyped Nelore cattle. Phenotype count for these animals ranged from 430 to 536 across traits. Meat quality traits in Nelore are controlled by numerous QTL of small effect, except for a small number of large-effect QTL identified for a*fat, CL and pH. Genomic regions harboring these QTL and the pathways in which the genes from these regions act appear to differ from those identified in taurine cattle for meat quality traits. These results will guide future QTL mapping studies and the development of models for the prediction of genetic merit to implement genomic selection for meat quality in Nelore cattle.

Tizioto PC; Decker JE; Taylor JF; Schnabel RD; Mudadu MA; Silva FL; Mourão GB; Coutinho LL; Tholon P; Sonstegard TS; Rosa AN; Alencar MM; Tullio RR; Medeiros SR; Nassu RT; Feijó GL; Silva LO; Torres RA; Siqueira F; Higa RH; Regitano LC

2013-09-01

 
 
 
 
261

Impact of Castration and Zeranol Implants on Bullocks: II. Organoleptic and Instrument Assessment of Tenderness  

Directory of Open Access Journals (Sweden)

Full Text Available The effects of Zeranol and castration on organoleptic and mechanically assessed tenderness were studied using the 193 young beef cattle described in the companion paper (Impact of castration and zeranol implants on bullocks: I. Behavior, growth and carcass traits). Sensory panel evaluations showed that steaks from control and implanted steer carcasses had higher mean scores for tenderness, juiciness, flavor and overall palatability than those from control and implanted bulls. Implanting did not influence juiciness or flavor within the bull or steer groups, but control bulls and steers were significantly (P<.005) more tender and more palatable overall than were implanted bulls and steers. When comparing the mechanical measurements there was considerable variation among the instruments. The Armour tenderometer ranked meat from the implanted steers significantly tougher than either the control or implanted bulls. The Warner-Bratzler shear, Krammer shear and Instron Press ranked steaks from steers significantly more tender than those from bulls. Implanted and control groups of animals were similar in tenderness when judged by the mechanical measurements. Behavior and palatability characteristics of implanted and control bulls and steers were also studied. Implantation made bulls and steers more docile. The libido measurements were also lower for the implanted bulls and steers. Within group of implanted bulls and steers those that were least aggressive tended to be more tender than their more aggressive counterparts.

Hawkins. E. W; R.A. Field; L.E. Orme; R.E. Dyer; D.K. Lunt

2005-01-01

262

Relationships between sensory and physicochemical measurements in meat of rabbit from three different breeding systems using canonical correlation analysis  

UK PubMed Central (United Kingdom)

Meat from rabbits reared either according to a standard (STAND) or a high quality norm (LABEL) or a low growth breeding (RUSSE) system were submitted to a sensory evaluation and to a large set of physicochemical measurements (weight of retail cuts, colour parameters, ultimate pH, femur flexure test, Warner-Bratzler shear test, water holding capacities and cooking losses). STAND rabbit meat exhibited the most juicy meat in back and in leg (p <0.01). Leg tenderness significantly decreased (p <0.001) in the rank order STAND>LABEL>RUSSE. Canonical correlation analysis showed strong correlations between physicochemical and sensory variables (R ² =0.73 and 0.68 between the two first pairs of canonical variates). Especially, sensory tenderness and WB shear test variables assessed on raw longissimus muscle (LL) were correlated. Fibrous attribute in back was correlated with cooking loss in LL. When analysed separately only RUSSE rabbits exhibited the same relations between variables as those calculated in whole dataset.

Combes Sylvie; González Ignacio; Déjean Sébastien; Baccini Alain; Jehl Nathalie; Juin Hervé; Cauquil Laurent; Gabinaud Béatrice; Lebas François; Larzul Catherine

2008-11-01

263

Effect of chilling applied to suckling lamb carcasses on hygienic, physicochemical and sensory meat quality.  

UK PubMed Central (United Kingdom)

The effect of post mortem temperature treatment on suckling lamb carcass and meat quality was study. Conventional (2 °C for 24 h), ultra-rapid (-20 °C for 3.5 h, 2 °C until 24 h) and slow chillings (12 °C for 7 h, 2 °C until 24 h) were compared. Total viable counts (TVC), weight losses, and pH and temperature falls were recorded on carcasses. Meat colour, water holding capacity (WHC), Warner-Bratzler shear force, sarcomere length and sensory analysis were evaluated in M. longissimus. Ultra-rapid treatment reduced TVC and weight losses. The pH decline was faster in slow chilled carcasses than in faster chilled carcasses. No significant differences were found for colour and WHC. Slow treatment carcasses showed significantly lower shear force and higher sarcomere length. In the sensory analysis, tasters also rated the early post mortem slow-treated meat as more tender, less fibrous and chewy. Therefore, delay chilling in suckling lamb carcasses made it possible to obtain meat with better organoleptic characteristics, without affecting weight loss or hygienic quality.

Fernández AM; Vieira C

2012-12-01

264

Shear modulus property characterization of nanorods.  

UK PubMed Central (United Kingdom)

We demonstrate an innovative technique for the direct measurement on the shear modulus of an individual nanorod. This measurement is based on atomic force microscopy (AFM) and microfabrication techniques. A nanorod is first aligned along the edge of a small trench in a silicon substrate, and then one end of the nanorod is fixed on the substrate. When an AFM tip scans over the nanorod in contact mode, the nanorod will be twisted by the comprehensive action from the force of the AFM tip, confinement from the trench edge and the fixing end. The shear deformation and the corresponding force that caused the deformation can be retrieved from topography and lateral force image, respectively. By small-angle approximation, the shear modulus of the ZnO NR, which has a radius of 166 nm and a length of 4 ?m, is measured to be 8.1 ± 1.9 GPa. This method can be applied directly to characterize the shear modulus of any nanowire/nanorod that possesses a polygon cross section.

Jiang C; Lu W; Song J

2013-01-01

265

Sheared flows and turbulence in fusion plasmas  

International Nuclear Information System (INIS)

The universality of the observed characteristics of sheared flows points to a general ingredient to explain the damping/driving mechanisms responsible for the development of these flows in the plasma boundary region of fusion devices. Experiments in the TJ-II stellarator showing that the generation of spontaneous sheared flows at the plasma edge requires a minimum plasma density or density gradient, open a unique possibility to characterize the dynamics of sheared flow development in fusion plasmas. The effective viscosity at the plasma edge can be deduced by means of the decay rate of the perpendicular flow measurement once the driving force has been removed. Changes in the plasma rotation and turbulence have been studied when an electric field is externally applied at the plasma edge. The relaxation of flows and radial electric fields has been compared in the edge plasma region of TJ-II stellarator and CASTOR tokamak showing a striking similarity. The findings can help to test neoclassical and anomalous damping mechanisms in fusion plasmas. Finally, the emergence of the plasma edge sheared flow as a function of plasma density can be explained using a simple second-order phase transition model that reproduces many of the features of the TJ-II experimental data while capturing the qualitative features of the transition near the critical point.

2007-01-01

266

Shear friction capacity of recycled concretes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this research was to determine the behavior of recycled concrete in response to the phenomenon of shear transfer. To perform it, a conventional control concrete and a concrete with 50% recycled coarse aggregate were designed. An additional goal was to shed light on how this behavior is mo...

González Fonteboa, B.; Martínez, F.; Carro, D.; Eiras, J.

267

Shear viscosity of a pion gas  

International Nuclear Information System (INIS)

The experimental data from RHIC, especially the measured elliptic flow indicate that the matter produced in Au+Au collisions exhibit properties which are more like a strongly interacting liquid than a weakly interacting gas. The shear viscosity ? or the internal friction of the fluid symbolizes the ability to transfer momentum over a distance of ? mean free path. Therefore, in a system where the constituents interact strongly the transfer of momentum is performed easily - resulting in lower values of ?. Consequently such a system may be characterized by a small value of ?/s. The importance of viscosity also lies in the fact that it damps out the variation in the velocity and make the fluid flow laminar. A very small viscosity (large Reynold number) may make the flow turbulent. Although a large amount of work has been done on shear viscosity in QGP phase, the shear viscosity in hadronic matter has received much less attention so far. In the present work shear viscosity has been evaluated in a kinetic theory approach by solving Boltzmann transport equation using the relaxation time approximation

2011-01-01

268

Study of Shear Viscosity of Amorphous Materials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Viscoelastic properties of amorphous solids deformed under uniform shear stress were studied using a kind of sandwich method with utilizing a sensitive optical technique. Time-dependent deformation data were analyzed on the basis of a mechanical model of anelasticity plus viscosity. Experiments were...

Hiki, Y.; Kobayashi, H.; Takahashi, H.

269

Size Segregation in Sheared Jammed Colloids  

Science.gov (United States)

It is well known that granular materials can spontaneously size segregate when continuously driven. However, in jammed colloidal suspensions, this phenomenon is not well understood. Colloidal dispersions provide a unique system to study the structure and dynamics of jammed matter. In this talk, we present results of size segregation of a continuously sheared binary colloidal suspension well above point J. Our colloidal system is comprised of indexed-matched bi-disperse silica particles with diameters a = 2.3?m and 3.2?m and at ? 61%, well above the colloidal glass transition. We apply a highly controlled shear at a constant shear rate through the use of a rheometer. By coupling our rheometer with a high-speed laser scanning confocal microscope, we directly image the structure and flow profiles of the suspension as it un-jams. We observe migration of the small and large species; large particles move to the top while the small particles move toward the bottom conserving the total volume fraction in all regions. Moreover, we find that an associating feature of segregation is a sustained shear band. Our results are consistent with a recently proposed void filling and squeeze expulsion mechanism.

Mbi, Armstrong; Blair, Daniel

2013-03-01

270

Crossing of shears bands in 196Pb  

International Nuclear Information System (INIS)

[en] High-spin states in 196Pb have been populated using the reaction 170Er(30Si, 4n). The previously observed shear bands in this nucleus have been extended and some of their transitions have been reordered. They now form regular bands with band crossings. One of the bands splits into two pathways at high spin. (orig.)

1996-01-01

271

Hydrodynamic Modeling and the QGP Shear Viscosity  

CERN Document Server

In this article, we will briefly review the recent progress on hydrodynamic modeling and the extraction of the quark-gluon plasma (QGP) specific shear viscosity with an emphasis on results obtained from the hybrid model VISHNU that couples viscous hydrodynamics for the macroscopic expansion of the QGP to the hadron cascade model for the microscopic evolution of the late hadronic stage.

Song, Huichao

2012-01-01

272

Shear viscosity of CFT plasma at finite coupling  

CERN Document Server

We present evidence for the universality of the shear viscosity of conformal gauge theory plasmas beyond infinite coupling. We comment of subtleties of computing the shear viscosity in effective models of gauge/gravity correspondence rather than in string theory.

Buchel, Alex

2008-01-01

273

Shear Viscosity from the Effective Coupling of Gravitons  

CERN Multimedia

We review the progress in the holographic calculation of shear viscosity for strongly coupled field theories. We focus on the calculation of shear viscosity from the effective coupling of transverse gravitons and present some explicit examples.

Cai, Rong-Gen; Sun, Ya-Wen

2010-01-01

274

Turbulent transport in tokamak plasmas with rotational shear.  

UK PubMed Central (United Kingdom)

Nonlinear gyrokinetic simulations are conducted to investigate turbulent transport in tokamak plasmas with rotational shear. At sufficiently large flow shears, linear instabilities are suppressed, but transiently growing modes drive subcritical turbulence whose amplitude increases with flow shear. This leads to a local minimum in the heat flux, indicating an optimal E×B shear value for plasma confinement. Local maxima in the momentum fluxes are observed, implying the possibility of bifurcations in the E×B shear. The critical temperature gradient for the onset of turbulence increases with flow shear at low flow shears; at higher flow shears, the dependence of heat flux on temperature gradient becomes less stiff. The turbulent Prandtl number is found to be largely independent of temperature and flow gradients, with a value close to unity.

Barnes M; Parra FI; Highcock EG; Schekochihin AA; Cowley SC; Roach CM

2011-04-01

275

Shear crack formation and propagation in reinforced Engineered Cementitious Composites  

DEFF Research Database (Denmark)

This paper describes an experimental investigation of the shear behaviour of beams consisting of steel reinforced Engineered Cementitious Composites (R/ECC). Based on the strain hardening and multiple cracking behaviour of ECC, this study investigates the extent to which ECC influences the shear capacity of beams loaded primarily in shear. The experimental program consists of ECC with short randomly distributed polyvinyl alcohol (PVA) fiber beams with different stirrup arrangements and conventional reinforced concrete (R/C) counterparts for comparison. The shear crack formation mechanism of ECC is investigated in detail and can be characterized by an opening and sliding of the crack. Photogrammetry was utilized to monitor the shear deformations of the specimens. Multiple shear cracking and strain hardening of ECC was observed under shear loading and based upon photogrammetric results fundamental descriptions of shear crack opening, sliding and subsequent failure are presented.

Paegle, Ieva; Fischer, Gregor

2011-01-01

276

Shear and loading in channels: Oscillatory shearing and edge currents of superconducting vortices  

Science.gov (United States)

Via computer simulations we study the motion of quantized magnetic flux-lines, or vortices, confined to a straight pin-free channel in a strong-pinning superconducting sample. We find that, when a constant current is applied across this system, a very unusual oscillatory shearing appears, in which the vortices moving at the edges of the channel periodically trail behind and then suddenly leapfrog past the vortices moving in the inner rows. For small enough driving forces, this oscillatory shearing dynamic phase is replaced by a continuous shearing phase in which the distance between initially-nearby vortices grows in time, quickly destroying the order of the lattice. An animation of this novel “oscillatory leapfrogging shear” effect of the vortex edge currents appears in http://www-personal.engin.umich.edu/˜nori/channel/

Wambaugh, J. F.; Marchesoni, F.; Nori, Franco

2003-04-01

277

Shear horizontal guided wave modes to infer the shear stiffness of adhesive bond layers.  

UK PubMed Central (United Kingdom)

This paper presents a non-destructive, ultrasonic technique to evaluate the quality of bonds between substrates. Shear-horizontally polarized (SH) wave modes are investigated to infer the shear stiffness of bonds, which is necessarily linked to the shear resistance that is a critical parameter for bonded structures. Numerical simulations are run for selecting the most appropriate SH wave modes, i.e., with higher sensitivity to the bond than to other components, and experiments are made for generating-detecting pre-selected SH wave modes and for measuring their phase velocities. An inverse problem is finally solved, consisting of the evaluation of the shear stiffness modulus of a bond layer at different curing times between a metallic plate and a composite patch, such assembly being investigated in the context of repair of aeronautical structures.

Le Crom B; Castaings M

2010-04-01

278

Effect of shear-induced diffusion on the transfer of heat across a sheared suspension  

Science.gov (United States)

Suspensions of non-Brownian particles undergoing shear provide a quasi-unique system where mixing occurs spontaneously at low Reynolds number. In essence, particles behave in the fluid as so many ``stirrers''. The questions raised are how do they affect the transport of heat/mass across sheared suspensions? What will be the influence of the particle size, their volume fraction and the applied shear? By using an index matched suspension and a laser induced fluorescence imaging technique, we were able to measure individual particle trajectories and correlate the particle diffusion motion to the thermal diffusion of the suspension. Shear-induced diffusion causes a significant enhancement (> 200%) of the suspension transport properties. Simulations which combine a Lattice Boltzman technique to solve the flow and a passive Brownian tracer algorithm to solve for the transfer of heat are in very good agreement with experiments.

Rahli, Ouamar; Yin, Xiaolong; Metzger, Bloen

2013-06-01

279

Collision statistics in sheared inelastic hard spheres.  

Science.gov (United States)

The dynamics of sheared inelastic-hard-sphere systems is studied using nonequilibrium molecular-dynamics simulations and direct simulation Monte Carlo. In the molecular-dynamics simulations Lees-Edwards boundary conditions are used to impose the shear. The dimensions of the simulation box are chosen to ensure that the systems are homogeneous and that the shear is applied uniformly. Various system properties are monitored, including the one-particle velocity distribution, granular temperature, stress tensor, collision rates, and time between collisions. The one-particle velocity distribution is found to agree reasonably well with an anisotropic Gaussian distribution, with only a slight overpopulation of the high-velocity tails. The velocity distribution is strongly anisotropic, especially at lower densities and lower values of the coefficient of restitution, with the largest variance in the direction of shear. The density dependence of the compressibility factor of the sheared inelastic-hard-sphere system is quite similar to that of elastic-hard-sphere fluids. As the systems become more inelastic, the glancing collisions begin to dominate over more direct, head-on collisions. Examination of the distribution of the times between collisions indicates that the collisions experienced by the particles are strongly correlated in the highly inelastic systems. A comparison of the simulation data is made with direct Monte Carlo simulation of the Enskog equation. Results of the kinetic model of Montanero [J. Fluid Mech. 389, 391 (1999)] based on the Enskog equation are also included. In general, good agreement is found for high-density, weakly inelastic systems. PMID:19518225

Bannerman, Marcus N; Green, Thomas E; Grassia, Paul; Lue, Leo

2009-04-22

280

Collision statistics in sheared inelastic hard spheres.  

UK PubMed Central (United Kingdom)

The dynamics of sheared inelastic-hard-sphere systems is studied using nonequilibrium molecular-dynamics simulations and direct simulation Monte Carlo. In the molecular-dynamics simulations Lees-Edwards boundary conditions are used to impose the shear. The dimensions of the simulation box are chosen to ensure that the systems are homogeneous and that the shear is applied uniformly. Various system properties are monitored, including the one-particle velocity distribution, granular temperature, stress tensor, collision rates, and time between collisions. The one-particle velocity distribution is found to agree reasonably well with an anisotropic Gaussian distribution, with only a slight overpopulation of the high-velocity tails. The velocity distribution is strongly anisotropic, especially at lower densities and lower values of the coefficient of restitution, with the largest variance in the direction of shear. The density dependence of the compressibility factor of the sheared inelastic-hard-sphere system is quite similar to that of elastic-hard-sphere fluids. As the systems become more inelastic, the glancing collisions begin to dominate over more direct, head-on collisions. Examination of the distribution of the times between collisions indicates that the collisions experienced by the particles are strongly correlated in the highly inelastic systems. A comparison of the simulation data is made with direct Monte Carlo simulation of the Enskog equation. Results of the kinetic model of Montanero [J. Fluid Mech. 389, 391 (1999)] based on the Enskog equation are also included. In general, good agreement is found for high-density, weakly inelastic systems.

Bannerman MN; Green TE; Grassia P; Lue L

2009-04-01

 
 
 
 
281

Spurious Shear in Weak Lensing with LSST  

Energy Technology Data Exchange (ETDEWEB)

The complete 10-year survey from the Large Synoptic Survey Telescope (LSST) will image {approx} 20,000 square degrees of sky in six filter bands every few nights, bringing the final survey depth to r {approx} 27.5, with over 4 billion well measured galaxies. To take full advantage of this unprecedented statistical power, the systematic errors associated with weak lensing measurements need to be controlled to a level similar to the statistical errors. This work is the first attempt to quantitatively estimate the absolute level and statistical properties of the systematic errors on weak lensing shear measurements due to the most important physical effects in the LSST system via high fidelity ray-tracing simulations. We identify and isolate the different sources of algorithm-independent, additive systematic errors on shear measurements for LSST and predict their impact on the final cosmic shear measurements using conventional weak lensing analysis techniques. We find that the main source of the errors comes from an inability to adequately characterise the atmospheric point spread function (PSF) due to its high frequency spatial variation on angular scales smaller than {approx} 10{prime} in the single short exposures, which propagates into a spurious shear correlation function at the 10{sup -4}-10{sup -3} level on these scales. With the large multi-epoch dataset that will be acquired by LSST, the stochastic errors average out, bringing the final spurious shear correlation function to a level very close to the statistical errors. Our results imply that the cosmological constraints from LSST will not be severely limited by these algorithm-independent, additive systematic effects.

Chang, C.; Kahn, S.M.; Jernigan, J.G.; Peterson, J.R.; AlSayyad, Y.; Ahmad, Z.; Bankert, J.; Bard, D.; Connolly, A.; Gibson, R.R.; Gilmore, K.; Grace, E.; Hannel, M.; Hodge, M.A.; Jee, M.J.; Jones, L.; Krughoff, S.; Lorenz, S.; Marshall, P.J.; Marshall, S.; Meert, A.

2012-09-19

282

[Renal urinary shear stress: a novel actor in nephropathies].  

UK PubMed Central (United Kingdom)

The role of fluid shear stress is well established in vascular pathophysiology. However, urinary shear stress now also appears as a key mechanism in the regulation of renal function. In addition, there is a growing body of evidence showing that modified urinary shear stress is involved in the development of nephropathies. Therefore we review here the state-of-the-art on the pathophysiological roles of urinary shear stress.

Gonzalez J; Essig M; Klein J; Caubet C; Dissard R; Bascands JL; Schanstra JP; Buffin-Meyer B

2013-03-01

283

Quantitative shear wave magnetic resonance elastography: comparison to a dynamic shear material test.  

Science.gov (United States)

Magnetic resonance elastography (MRE), a phase contrast MRI technique, images the propagation of applied mechanical waves in tissue, allowing shear stiffness to be quantified in vivo. This MRE technique has been validated with static mechanical compression tests. Dynamic mechanical analysis (DMA) may be a more appropriate comparison to MRE because it directly measures the shear modulus dynamically, while compression tests convert the measured elastic modulus to shear modulus with an assumed Poisson ratio. This study compared the shear stiffness estimated with various MRE inversion algorithms (i.e., manual calculation, local frequency estimate, phase gradient, direct inversion, and matched filter) to the dynamic mechanical test. The shear stiffness of five agarose gels with concentrations ranging from 1.5 to 3.5% were measured using MRE and DMA. The phase gradient inversion algorithm overestimated the shear modulus at higher concentrations (i.e., 3-3.5% agar), while the results from the other techniques correlated well with the dynamic mechanical test. PMID:15844144

Ringleb, Stacie I; Chen, Qingshan; Lake, David S; Manduca, Armando; Ehman, Richard L; An, Kai-Nan

2005-05-01

284

Estimation of seabed shear-wave velocity profiles using shear-wave source data.  

UK PubMed Central (United Kingdom)

This paper estimates seabed shear-wave velocity profiles and their uncertainties using interface-wave dispersion curves extracted from data generated by a shear-wave source. The shear-wave source generated a seismic signature over a frequency range between 2 and 60 Hz and was polarized in both in-line and cross-line orientations. Low-frequency Scholte- and Love-waves were recorded. Dispersion curves of the Scholte- and Love-waves for the fundamental mode and higher-order modes are extracted by three time-frequency analysis methods. Both the vertically and horizontally polarized shear-wave velocity profiles in the sediment are estimated by the Scholte- and Love-wave dispersion curves, respectively. A Bayesian approach is utilized for the inversion. Differential evolution, a global search algorithm is applied to estimate the most-probable shear-velocity models. Marginal posterior probability profiles are computed by Metropolis-Hastings sampling. The estimated vertically and horizontally polarized shear-wave velocity profiles fit well with the core and in situ measurements.

Dong H; Nguyen TD; Duffaut K

2013-07-01

285

Fluid shear induced endothelial cell detachment from glass--influence of adhesion time and shear stress.  

UK PubMed Central (United Kingdom)

In this study, human umbilical vein and human saphenous vein endothelial cells were seeded on glass and exposed to fluid shear in a parallel-plate flow chamber. Cell retention, morphology and migration were studied as a function of shear stress and of adhesion time prior to exposure to shear. Three-hour and 24-h adhesion times gave rise to comparable cell retention values after 2 h of flow for both cell types. Cell retention decreased from 85 to 20% as shear stress increased from 88 to 264 dynes cm-2 (8.8 to 26 Pa). Mean spreading areas decreased after the onset of flow, but subsequently stabilized to plateau values, which were smaller at higher shear stresses. Shape factors increased faster to higher values as cells were exposed to higher shear stresses, without any obvious preference in orientation of the cells with respect to the direction of flow. Migration was unidirectional with flow and linear with time. Migration was faster for cells which had adhered for 24 h than for cells which had adhered for 3 h and was accompanied by the presence of fibrillar structures left behind on the surface upstream of migrating cells. It is concluded that after 3 h adhesion to glass, cells have adhered with an adhesion strength that does not substantially increase during the next 21 h. However, during this time changes in cell-substratum interactions seem to occur judging by the differences in, e.g., migration rates.

van Kooten TG; Schakenraad JM; van der Mei HC; Dekker A; Kirkpatrick CJ; Busscher HJ

1994-11-01

286

Reduction in transport by the parallel velocity shear instability due to reversed magnetic shear  

International Nuclear Information System (INIS)

[en] A nonlocal theory of the electrostatic parallel velocity shear instability in a three-dimensional slab with a uniformly sheared magnetic field has been developed. It is shown that in the limit of a weak parallel velocity gradient, the linear growth rate can be increased depending upon the direction of the magnetic shear (s) with respect to the radial curvature of the parallel velocity profile (d2v#parallel#/dx2). When these parameters have the same sign, the growth rate can actually be stronger than in the limit of no magnetic shear. In this limit of increased instability, the eigenmode is broadened, thus producing enhanced transport. This effect should be observable when the scale length of the curvature is of order ?Ls?s. For strong parallel velocity gradients that are more typical of flows in tokamaks, the effect of the varying Doppler shift becomes more prominent on the stability of the mode, the net result being that the sensitivity of the growth rates on the sign of the magnetic shear becomes insignificant. This effect, however, is effectively offset when a finite density gradient is included. When the density scale length is of order the scale length of v#parallel#, the growth rate is moderately reduced, but becomes dependent again upon the sign of the magnetic shear

2001-01-01

287

Reduction in transport by the parallel velocity shear instability due to reversed magnetic shear  

Energy Technology Data Exchange (ETDEWEB)

A nonlocal theory of the electrostatic parallel velocity shear instability in a three-dimensional slab with a uniformly sheared magnetic field has been developed. It is shown that in the limit of a weak parallel velocity gradient, the linear growth rate can be increased depending upon the direction of the magnetic shear (s) with respect to the radial curvature of the parallel velocity profile (d{sup 2}v{sub {parallel}}/dx{sup 2}). When these parameters have the same sign, the growth rate can actually be stronger than in the limit of no magnetic shear. In this limit of increased instability, the eigenmode is broadened, thus producing enhanced transport. This effect should be observable when the scale length of the curvature is of order {approx}L{sub s}{rho}{sub s}. For strong parallel velocity gradients that are more typical of flows in tokamaks, the effect of the varying Doppler shift becomes more prominent on the stability of the mode, the net result being that the sensitivity of the growth rates on the sign of the magnetic shear becomes insignificant. This effect, however, is effectively offset when a finite density gradient is included. When the density scale length is of order the scale length of v{sub {parallel}}, the growth rate is moderately reduced, but becomes dependent again upon the sign of the magnetic shear.

McCarthy, D. R.; Fuselier, E. J.; Sen, S.

2001-08-01

288

Separate structure of two branches of sheared slab ?i mode and effects of plasma rotation shear in weak magnetic shear region  

International Nuclear Information System (INIS)

[en] The separate structure of two branches of the sheared slab ?i mode near the minimum-q magnetic surface is analysed and the effects of plasma rotation shears are considered in the weak magnetic shear region. Results show that the separation condition depends on the non-monotonous q profile and the deviation of rational surface from the minimum-q surface. Furthermore, it is found that the diamagnetic rotation shear may suppress the perturbation of the sheared slab ?i mode at one side of the minimum-q surface, the poloidal rotation shear from the sheared E-vector x B-vector flow has a similar role to the slab mode structure when it possesses a direction same as the diamagnetic shear. A plausible interrelation between the separate structures of the two branches of the sheared slab mode and the discontinuity or gap of the radially global structure of the drift wave near the minimum-q surface observed in the toroidal particle simulation (Kishimoto Y et al 1998 Plasma Phys. Control. Fusion 40 A663) is discussed. It seems to support such a viewpoint: the double or/and global branches of the sheared slab ?i mode near the minimum-q surface may become a bridge to connect the radially global structures of the drift wave at two sides of the minimum-q surface and the discontinuity may originate from the separate structures of these slab modes for a flatter q profile. (author)

2000-01-01

289

Shear Deflection of Two Species Laminated Wood BEAMS.  

Science.gov (United States)

In addition to the deflection due to pure bending in a beam, there is a shear force in all cases of non-uniform bending and a further deflection, due to shear stresses. This additional shear deflection usually is assumed to be negligible and is not consid...

E. J. Biblis

1966-01-01

290

Control over colloidal crystallization by shear and electric fields  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We used shear flow and an electric field to control colloidal crystallization. The structures were examined in situ with confocal microscopy. For experiments under shear, a new parallel plate shear cell was designed. It had a zero-velocity plane that was stationary with respect to the microscope. Th...

Wu, Y.L.

291

Fluid Effects on Shear Waves in FInely Layered Porous Media  

Energy Technology Data Exchange (ETDEWEB)

Although there are five effective shear moduli for any layered VTI medium, one and only one effective shear modulus for the layered system contains all the dependence of pore fluids on the elastic or poroelastic constants that can be observed in vertically polarized shear waves. Pore fluids can increase the magnitude the shear energy stored by this modulus by a term that ranges from the smallest to the largest shear moduli of the VTI system. But, since there are five shear moduli in play, the increase in shear energy overall is reduced by a factor of about 5 in general. We can therefore give definite bounds on the maximum increase of shear modulus, being about 20% of the permitted range, when gas is fully replaced by liquid. An attendant increase of density (depending on porosity and fluid density) by approximately 5 to 10% partially offsets the effect of this shear modulus increase. Thus, an increase of shear wave speed on the order of 5 to 10% is shown to be possible when circumstances are favorable - i.e., when the shear modulus fluctuations are large (resulting in strong anisotropy), and the medium behaves in an undrained fashion due to fluid trapping. At frequencies higher than seismic (such as sonic and ultrasonic waves for well-logging or laboratory experiments), short response times also produce the requisite undrained behavior and, therefore, fluids also affect shear waves at high frequencies by increasing rigidity.

Berryman, J G

2004-05-21

292

Elastic signature of flow events in supercooled liquids under shear.  

UK PubMed Central (United Kingdom)

Using numerical simulation of a 2D Lennard-Jones system, we study the crossover from shear thinning to Newtonian flow. We find that the short-time elastic response of our system essentially does not change through this crossover, and show that, in the Newtonian regime, thermal activation triggers shear transformations, i.e., local irreversible shear events that produce Eshelby (long-ranged, anisotropic) deformation fields as previously seen in low-T glasses. Quite surprisingly, these Eshelby fields are found to persist much beyond the ?-relaxation time, and shear thinning to coincide with the emergence of correlations between shear relaxation centers.

Chattoraj J; Lemaître A

2013-08-01

293

Effect of Aging on Deformability of Erythrocytes in Shear Flow  

Directory of Open Access Journals (Sweden)

Full Text Available To study the effect of aging on deformability of an erythrocyte, rheological measurement has been performed after exposure to a shear field in vitro. Deformability was evaluated with shear stress responsiveness and with critical elongation calculated from an exponential curve between an elongation index and shear stress. Human erythrocytes were classified according to their density by a centrifugal method. Deformability decreases in erythrocytes of high density after shearing. Even after exposure to the shear field of 640 1/s for one hour, erythrocytes deform from biconcave to ellipsoidal and their deformability is maintained.

Shigehiro HASHIMOTO; Shuichi MOCHIZUKI; Yusuke MORITA; Hajime OTANI; Hiroji IMAMURA; Toshiji IWASAKA

2005-01-01

294

CLAMPING AND SHEARING HEAD FOR A TREE HARVESTER  

UK PubMed Central (United Kingdom)

A clamping and shearing head for a tree harvester employing a single pair of actuating cylinders for clamping and shearing. The piston rod of each cylinder acts directly on a shear blade while the cylinder body acts on a tree clamp member through a trunnion mount and bellcrank arrangement. As the shear blade closes against a tree the reaction forces on the cylinder body, acting through the trunnion mount, cause the bellcrank to rotate to close the clamp member against the tree. Once the clamp has closed on the tree the piston rod continues to extend to move the shear blade through the tree trunk.

WINDSOR R

295

Elastic Signature of Flow Events in Supercooled Liquids Under Shear  

Science.gov (United States)

Using numerical simulation of a 2D Lennard-Jones system, we study the crossover from shear thinning to Newtonian flow. We find that the short-time elastic response of our system essentially does not change through this crossover, and show that, in the Newtonian regime, thermal activation triggers shear transformations, i.e., local irreversible shear events that produce Eshelby (long-ranged, anisotropic) deformation fields as previously seen in low-T glasses. Quite surprisingly, these Eshelby fields are found to persist much beyond the ?-relaxation time, and shear thinning to coincide with the emergence of correlations between shear relaxation centers.

Chattoraj, Joyjit; Lemaître, Anaël

2013-08-01

296

Investigation of polymer brushes and adsorbed layers under shear  

International Nuclear Information System (INIS)

Neutron reflectometry was used to investigate the density profiles of polymer brushes and an adsorbed polymer layer under shear. The brushes consisted of end-functionalized deuterated polystyrene. The adsorbed polymer was a random copolymer of deuterated styrene and 4-vinylpyridine. The brush and the adsorbed layer were sheared by the flowing of solvents over the polymer, with a maximum shear rate of 104s-1. Density profiles of the brush and the layer were determined before, during and after shear. The shear had no observable effect on the polymer profiles in any of the experiments. We discuss these results in the context of other experiments and a recent theory. (orig.).

1997-01-01

297

Elastic signature of flow events in supercooled liquids under shear.  

Science.gov (United States)

Using numerical simulation of a 2D Lennard-Jones system, we study the crossover from shear thinning to Newtonian flow. We find that the short-time elastic response of our system essentially does not change through this crossover, and show that, in the Newtonian regime, thermal activation triggers shear transformations, i.e., local irreversible shear events that produce Eshelby (long-ranged, anisotropic) deformation fields as previously seen in low-T glasses. Quite surprisingly, these Eshelby fields are found to persist much beyond the ?-relaxation time, and shear thinning to coincide with the emergence of correlations between shear relaxation centers. PMID:23971590

Chattoraj, Joyjit; Lemaître, Anaël

2013-08-08

298

Search for shears mechanism in 142Sm  

International Nuclear Information System (INIS)

Generation of angular momentum in weakly deformed nuclei by shears mechanism is a well known phenomenon in nuclear structure physics. During the last two decades, rotational-like bands consisting of dipole transitions have been observed systematically near the spherical region and interpreted as Magnetic Rotor. In this mechanism the total angular momentum along the band is generated by the gradual alignment of the two angular momentum blades and the shears arrangement of the high j orbital give rise to a large transverse magnetic dipole moment. In the present INGA experiments at TIFR, the level structure of 141,142Sm is studied in order to look for the possible observation of magnetic and anti magnetic rotational bands by measuring the life time of the excited states using DSAM technique

2012-01-01

299

Holographic Chiral Shear Waves from Anomaly  

International Nuclear Information System (INIS)

We study dispersion relations of hydrodynamic waves of hot N=4 SYM plasma at strong coupling with a finite U(1) R-charge chemical potential via holography. We first provide complete equations of motion of linearized fluctuations out of a charged AdS blackhole background according to their helicity, and observe that helicity ±1 transverse shear modes receive a new parity-odd contribution from the 5D Chern-Simons term, which is dual to 4D U(1)3 anomaly. We present a systematic solution of the helicity ±1 wave equations in long wave-length expansion, and obtain the corresponding dispersion relations. The results depen d on the sign of helicity, which may be called chiral shear waves. (author)

2009-01-01

300

Bulk and Shear Viscosity in Hagedorn Fluid  

CERN Document Server

Assuming that the Hagedorn fluid composed of known particles and resonances with masses $m<2\\,$GeV obeys the {\\it first-order} theory (Eckart) of relativistic fluid, we discuss the transport properties of QCD confined phase. Based on the relativistic kinetic theory formulated under the relaxation time approximation, expressions for bulk and shear viscosity in thermal medium are derived. The relaxation time in the Hagedorn dynamical fluid exclusively takes into account the decay and eventually van der Waals processes. We comment on the {\\it in-medium} thermal effects on bulk and shear viscosities and averaged relaxation time with and without the excluded-volume approach. As an application of these results, we suggest the dynamics of heavy-ion collisions, non-equlibrium thermodynamics and the cosmological models, which require thermo and hydrodynamics equations of state.

Tawfik, A

2010-01-01

 
 
 
 
301

Shear unzipping of double stranded DNA  

CERN Document Server

We propose a simple nonlinear scaler displacement model to calculate the distribution of effect created by a shear stress on a double stranded DNA (dsDNA) molecule and the value of shear force $F_c$ which is required to separate the two strands of a molecule. It is shown that as long as the force pulls entire strand in the direction of its application the value of $F_c$ depends linearly on the length; the deviation from linear behaviour takes place when part of a strand moves in opposite direction under the influence of force acting on the other strand. The calculated values of $F_c$ as a function of length of dsDNA molecules are in very good agreement with the experimental values of Hatch et al (Phys. Rev. E $\\bf 78$, 011920 (2008)).

Prakash, Shikha

2011-01-01

302

Brownian forces in sheared granular matter  

CERN Multimedia

The response of granular matter to a slow applied shear is erratic and intermittent, the so called "stick-slip" motion. In this state, observable quantities can display power law statistics in common with many other phenomena ranging from solid-on-solid friction to earthquakes, suggesting analogies between such different phenomena. Here we present results from a series of experiments on a granular medium sheared in a Couette geometry and show that their statistical properties can be computed in a quantitative way from the assumption that the resultant from the set of forces acting in the system performs a Brownian motion. The same assumption has been utilised, with success, to describe other phenomena, such as the Barkhausen effect in ferromagnets, and so the scheme suggests itself as a more general description of a wider class of driven instabilities.

Baldassarri, A; Petri, A; Zapperi, S; Pontuale, G; Pietronero, L; Baldassarri, Andrea; Dalton, Fergal; Petri, Alberto; Zapperi, Stefano; Pontuale, Giorgio; Pietronero, Luciano

2005-01-01

303

Implications of Orientation in Sheared Cocoa Butter  

Science.gov (United States)

We will present x-ray and mechanical studies of oriented phases of cocoa butter. The structural elements of foods play an important role in determining such things as quality and shelf stability. The specific structure and properties of cocoa butter, however, are complicated due to the ability of the cocoa butter to form crystals in six polymorphic forms. Recent work has shown that the application of shear not only accelerates the transitions to more stable polymorphs, but also causes orientation of the crystallites[1]. The implications of orientation on the structures formed under conditions of shear and cooling will be described using x-ray diffraction and mechanical measurements. 1 G. Mazzanti, S. E. Guthrie, E. B. Sirota et al., Crystal Growth & Design 3 (5), 721 (2003).

Guthrie, Sarah E.; Mazzanti, Gianfranco; Marangoni, Alejandro; Idziak, Stefan H. J.

2004-03-01

304

Magnetic reconnection in sheared solar magnetic arcades  

Energy Technology Data Exchange (ETDEWEB)

The evolution of solar magnetic arcades is investigated with the use of MHD simulations imposing resistivity on sheared magnetic fields. It is found that there is a critical amount of shear, over which magnetic reconnection can take place in an arcade-like field geometry to create a magnetic island. The process leading to reconnection cannot be solely attributed to a tearing instability, but rather to a reactive evolution of the magnetic arcade under resistivity. The natures of the arcade reconnection are governed by the spatial pattern of resistivity. A fast reconnection with a small shock angle can only be achieved when the diffusion region is localized. In this case, a highly collimated reconnection outflow can tear the plasmoid into a pair, and most of principal features in solar eruptive processes are reproduced.

Choe, G.S.

1996-12-31

305

Magnetic Reconnection In Sheared Solar Magnetic Arcades  

UK PubMed Central (United Kingdom)

The evolution of solar magnetic arcades is investigated with the use of MHD simulations imposing resistivityon sheared magnetic fields. It is found that there is a critical amount of shear, over which magnetic reconnectioncan take place in an arcade-like field geometry to create a magnetic island. The process leading to reconnectioncannot be solely attributed to a tearing instability, but rather to a reactive evolution of the magnetic arcadeunder resistivity. The natures of the arcade reconnection are governed by the spatial pattern of resistivity. A fastreconnection with a small shock angle can only be achieved when the diffusion region is localized. In this case, ahighly collimated reconnection outflow can tear the plasmoid into a pair, and most of principal features in solareruptive processes are reproduced.Key Words : Sun: magnetic fields, Sun: flares, MHDI. INTRODUCTIONIt is widely believed that magnetic reconnectionplays an important role in solar eruptive phenomena...

G. S. Choe

306

Bac clones generated from sheared dna  

Energy Technology Data Exchange (ETDEWEB)

BAC libraries generated from restriction-digested genomic DNA display representational bias and lack some sequences. To facilitate completion of genome projects, procedures have been developed to create BACs from DNA physically sheared to create fragments extending up to 200kb. The DNA fragments were repaired to create blunt ends and ligated to a new BAC vector. This approach has been tested by generating BAC libraries from Drosophila DNA, with insert lengths of 50 kb to 150 kb. The libraries lack chimeric clone problems as determined by mapping paired BAC-end sequences of one library to the D. melanogaster genome sequence. The utility of ''sheared'' libraries was demonstrated by closure of a previous clone gap and by isolation of clones from telomeric regions, which were notably absent from previous Drosophila BAC libraries.

Osoegawa, Kazutoyo; Vessere, Gery M.; Shu, Chung Li; Hoskins,Roger A.; Abad, Jose P.; de Pablos, Beatriz; Villasante, Alfredo; deJong, Pieter J.

2006-08-09

307

Yield strain in shear banding amorphous solids.  

UK PubMed Central (United Kingdom)

In recent research it was found that the fundamental shear-localizing instability of amorphous solids under external strain, which eventually results in a shear band and failure, consists of a highly correlated array of Eshelby quadrupoles all having the same orientation and some density ?. In this paper we calculate analytically the energy E(?,?) associated with such highly correlated structures as a function of the density ? and the external strain ?. We show that for strains smaller than a characteristic strain ?(Y) the total strain energy initially increases as the quadrupole density increases, but that for strains larger than ?(Y) the energy monotonically decreases with quadrupole density. We identify ?(Y) as the yield strain. Its value, derived from values of the qudrupole strength based on the atomistic model, agrees with that from the computed stress-strain curves and broadly with experimental results.

Dasgupta R; Hentschel HG; Procaccia I

2013-02-01

308

Yield strain in shear banding amorphous solids  

Science.gov (United States)

In recent research it was found that the fundamental shear-localizing instability of amorphous solids under external strain, which eventually results in a shear band and failure, consists of a highly correlated array of Eshelby quadrupoles all having the same orientation and some density ?. In this paper we calculate analytically the energy E(?,?) associated with such highly correlated structures as a function of the density ? and the external strain ?. We show that for strains smaller than a characteristic strain ?Y the total strain energy initially increases as the quadrupole density increases, but that for strains larger than ?Y the energy monotonically decreases with quadrupole density. We identify ?Y as the yield strain. Its value, derived from values of the qudrupole strength based on the atomistic model, agrees with that from the computed stress-strain curves and broadly with experimental results.

Dasgupta, Ratul; Hentschel, H. George E.; Procaccia, Itamar

2013-02-01

309

Drop impact of shear thickening liquids  

CERN Document Server

The impact of drops of concentrated non-Brownian suspensions (cornstarch and polystyrene spheres) onto a solid surface is investigated experimentally. The spreading dynamics and maxi- mal deformation of the droplet of such shear thickening liquids are found to be markedly different from the impact of Newtonian drops. A particularly striking observation is that the maximal de- formation is independent of the drop velocity and that the deformation suddenly stops during the impact phase. Both observations are due to the shear-thickening rheology of the suspensions, as is theoretically explained from a balance between the kinetic energy and the viscously-dissipated en- ergy, from which we establish a scaling relation between drop maximal deformation and rheological parameters of concentrated suspensions.

Boyer, Francois; Dijksman, J Frits; Lohse, Detlef

2013-01-01

310

Microstructure and velocity fluctuations in sheared suspensions  

CERN Document Server

The velocity fluctuations present in macroscopically homogeneous suspensions of neutrally buoyant, non-Brownian spheres undergoing simple shear flow, and their dependence on the microstructure developed by the suspensions, are investigated in the limit of vanishingly small Reynolds numbers using Stokesian dynamics simulations. We show that, in the dilute limit, the standard deviation of the velocity fluctuations is proportional to the volume fraction, in both the transverse and the flow directions, and that a theoretical prediction, which considers only for the hydrodynamic interactions between isolated pairs of spheres, is in good agreement with the numerical results at low concentrations. We also simulate the velocity fluctuations that would result from a random hard-sphere distribution of spheres in simple shear flow, and thereby investigate the effects of the microstructure on the velocity fluctuations. Analogous results are discussed for the fluctuations in the angular velocity of the suspended spheres. ...

Drazer, G; Khusid, B; Acrivos, A

2003-01-01

311

Shear and rotation in Chaplygin cosmology  

CERN Multimedia

We study the effect of shear and rotation on results previously obtained dealing with the application of the spherical collapse model (SCM) to generalized Chaplygin gas (gCg) dominated universes. The system is composed of baryons and gCg and the collapse is studied for different values of the parameter $\\alpha$ of the gCg. We show that the joint effect of shear and rotation is that of slowing down the collapse with respect to the simple SCM. This result is of utmost importance for the so-called unified dark matter models, since the described slow down in the growth of density perturbation can solve one of the main problems of the quoted models, namely the instability described in previous papers [e.g., H. B. Sandvik {\\it et al.}, Phys. Rev. D {\\bf 69}, 123524 (2004)] at the linear perturbation level.

Del Popolo, A; Maydanyuk, S P; Lima, J A S; Jesus, J F; 10.1103/PhysRevD.87.043527

2013-01-01

312

Stochastically driven instability in rotating shear flows  

CERN Multimedia

Origin of hydrodynamic turbulence in rotating shear flows is investigated. The particular emphasis is the flows whose angular velocity decreases but specific angular momentum increases with increasing radial coordinate. Such flows are Rayleigh stable, but must be turbulent in order to explain observed data. Such a mismatch between the linear theory and observations/experiments is more severe when any hydromagnetic/magnetohydrodynamic instability and then the corresponding turbulence therein is ruled out. The present work explores the effect of stochastic noise on such hydrodynamic flows. We essentially concentrate on a small section of such a flow which is nothing but a plane shear flow supplemented by the Coriolis effect. This also mimics a small section of an astrophysical accretion disk. It is found that such stochastically driven flows exhibit large temporal and spatial correlations of perturbation velocities, and hence large energy dissipations of perturbation, which presumably generate instability. A ra...

Mukhopadhyay, Banibrata

2012-01-01

313

Flocculation of model algae under shear.  

Energy Technology Data Exchange (ETDEWEB)

We present results of molecular dynamics simulations of the flocculation of model algae particles under shear. We study the evolution of the cluster size distribution as well as the steady-state distribution as a function of shear rates and algae interaction parameters. Algal interactions are modeled through a DLVO-type potential, a combination of a HS colloid potential (Everaers) and a yukawa/colloid electrostatic potential. The effect of hydrodynamic interactions on aggregation is explored. Cluster strucuture is determined from the algae-algae radial distribution function as well as the structure factor. DLVO parameters including size, salt concentration, surface potential, initial volume fraction, etc. are varied to model different species of algae under a variety of environmental conditions.

Pierce, Flint; Lechman, Jeremy B.

2010-11-01

314

A wall-shear stress predictive model  

Energy Technology Data Exchange (ETDEWEB)

Following the approach of Marusic et al. (2010b), here we develop a predictive model for the fluctuating wall-shear stress, where the only required input is large-scale information of the streamwise velocity at a location in the outer, logarithmic region of the flow. The model consists of two components, incorporating a superposition and modulation effect of outer region motions that interact with the flow field in the viscous sublayer. The model is seen to capture Reynolds number trends reliably.

Marusic, Ivan; Mathis, Romain; Hutchins, Nicholas, E-mail: imarusic@unimelb.edu.au [Department of Mechanical Engineering, University of Melbourne, Victoria 3010 (Australia)

2011-12-22

315

Shear flow pumping in open microfluidic systems  

CERN Multimedia

We propose to drive open microfluidic systems by shear in a covering fluid layer, e.g., oil covering water-filled chemical channels. The advantages as compared to other means of pumping are simpler forcing and prevention of evaporation of volatile components. We calculate the expected throughput for straight channels and show that devices can be built with off-the-shelf technology. Molecular dynamics simulations suggest that this concept is scalable down to the nanoscale.

Rauscher, M; Koplik, J; Rauscher, Markus; Koplik, Joel

2006-01-01

316

Structures and shear response of lipid monolayers  

International Nuclear Information System (INIS)

This report discusses our work during the last 3 years using x-ray diffraction and shear measurements to study lipid monolayers (membranes). The report is divided into: (1) structure: phase diagram of saturated fatty acid Langmuir monolayers, effect of head group interactions, studies of transferred monolayers (LB films); (2) mechanical properties: fiber=optic capillary wave probe and centrosymmetric trough, mechanical behavior of heneicosanoic acid monolayer phases

1993-01-01

317

Smoothed particle hydrodynamic simulations of shear flow  

Science.gov (United States)

This paper is concerned with the smoothed particle hydrodynamic (SPH) simulation of shear flow and the recent claim by Imaeda & Inutsuka that SPH has a fundamental flaw that is revealed by shear flow simulations. In order to clarify the SPH simulations, we study several representative shear flows. First, to compare against realistic exact time-dependent solutions, we simulate steady, periodic, low Mach number, inviscid shear flow in rectangular domains and the time-dependent, viscous, low Mach number evolution of both Couette flow in a rectangular domain and axisymmetric spin-down in a cylinder. These simulations are in good agreement with exact solutions. Secondly, to determine how well SPH simulates astrophysical discs, we simulate a differentially rotating, adiabatic, self-gravitating disc using as initial states variable-mass particles on a lattice, equal-mass particles on rings and on a lattice, and particles placed at random. The results show that the SPH results agree well with theory and are independent of the initial particle setup provided they are settled to equilibrium. Thirdly, we simulate a thin, two-dimensional, gaseous torus orbiting a gravitating mass and show that it is stable for at least the time integrated, and that when strongly perturbed the motion conserves circulation. None of these systems shows the huge density fluctuations found by Imaeda & Inutsuka. The flaw in the argument of Imaeda & Inutsuka may be the way they set up the initial configurations, but this is not certain because they do not describe their initial setup in sufficient detail to allow their simulations to be repeated. The conclusions of the present paper are in agreement with those obtained recently by Price, who simulated some of the systems considered by Imaeda & Inutsuka and found that the SPH results were in good agreement with theory.

Monaghan, J. J.

2006-01-01

318

Flower-thinning fruit-thinning shears for fruit tree  

UK PubMed Central (United Kingdom)

A flower-fruit thinning shear used for the fruit trees belongs to the special shearing tool for thinning the flower of the fruit tree, which consists of two parts that are symmetrical to each other the left and the right shear are hinged with each other the blade of the right and the left shear is U shape, two knife blades having the same shearing direction are straightly arranged on the U-shaped shear blade the right and the left part have four knife blades to form two pairs of shears so as to synchronically complete the shearing function. When thinning the fruits and the flowers, the remained flower bud is arranged in the gap outside of the knife blade, and the other flower buds are arranged inside the two shearing ports the surplus flower bud can be cut off only by one time of shearing, which improves three to four times of the working efficiency compared to the ordinary shear moreover, the utility model saves time and labor, which can be widely used for thinning the flowers and fruits of the apple, pear and orange.

YONGJIE BAI

319

Permeability anisotropy in clay-rich shear zones  

International Nuclear Information System (INIS)

A series of permeability measurements are presented on a consolidated and sheared smectite-rich clay from the Barbados accretionary complex using custom-designed oedometric and ring shear permeameters. The clay, when sheared under fully drained conditions, developed permeability anisotropy with progressive consolidation and shear displacement, increasing from around 15 at 100 kPa effective stress to over 35 at effective stresses of up to 20 MPa. The consolidated clay had a similar level of absolute permeability to that of the sheared clay in the direction parallel to the shear zone. These results suggest that high levels of anisotropic permeability in shear zones cannot by caused by clay fabric alignment alone. Other mechanism is required to explain enhanced fluid flow observed along the decollement of the Barbados accretionary complex. (R.P.)

1998-01-01

320

Localization of shearing deformations in tungsten heavy alloys  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the results of an investigation into the dynamic shearing deformations of a W-Ni-Fe heavy alloy containing 91% W and with the Ni and Fe in a 7:3 ratio. The technique used to develop the dynamic shearing deformations is the torsional Kolsky bar, which generates shear rates as high as 10(exp 3)/s for times of several hundred micro s. Adiabatic shear localization has been observed in the high-rate shearing tests; relatively narrow shear bands are formed, followed immediately by catastrophic fracture. The deformed microstructures are examined using scanning electron microscopy, optical microscopy, and quantitative image analysis of the micrographs. Examination of the deformed microstructures supplies new insight into the mechanisms through which large dynamic shearing deformations occur in this tungsten heavy alloy.

Ramesh, K.T.

1994-12-31

 
 
 
 
321

Turbulent transport in tokamak plasmas with rotational shear  

CERN Multimedia

Nonlinear gyrokinetic simulations have been conducted to investigate turbulent transport in tokamak plasmas with rotational shear. At sufficiently large flow shears, linear instabilities are suppressed, but transiently growing modes drive subcritical turbulence whose amplitude increases with flow shear. This leads to a local minimum in the heat flux, indicating an optimal E x B shear value for plasma confinement. Local maxima in the momentum fluxes are also observed, allowing for the possibility of bifurcations in the E x B shear. The sensitive dependence of heat flux on temperature gradient is relaxed for large flow shear values, with the critical temperature gradient increasing at lower flow shear values. The turbulent Prandtl number is found to be largely independent of temperature and flow gradients, with a value close to unity.

Barnes, M; Highcock, E G; Schekochihin, A A; Cowley, S C; Roach, C M

2010-01-01

322

Influence of Reinforced Concrete Shear Wall on Multistorey Buildings  

Directory of Open Access Journals (Sweden)

Full Text Available This work presents the behavior and change in length of shear wall in buildings varied by increasing equal heights from 3.5m to 28m i.e, ground storey (G) to G+7 keeping thickness of shear wall as constant of 250mm and observing the dimension of shear wall in length only. The study was carried by considering both wind and seismic forces for all the zones and soil types as per IS: 1893(part I):2002 and wind loads as per IS: 875(part III):1987. A total of 96 buildings were analyzed for this work using RESIST software. Buildings with symmetrical dimensions (20mx20m), varying wall length and keeping wall thickness as constant (250mm) the effect of shear wall length, wind drift, wind shear, wind moment, seismic drift, seismic shear, and seismic moment, base moment, base shear are studied and results are presented in graphs with height.

Venkata Sairam Kumar.N; Krishna Sai.M.L.N; Satyanarayana.S

2013-01-01

323

Atomic structure of amorphous shear bands in boron carbide.  

UK PubMed Central (United Kingdom)

Amorphous shear bands are the main deformation and failure mode of super-hard boron carbide subjected to shock loading and high pressures at room temperature. Nevertheless, the formation mechanisms of the amorphous shear bands remain a long-standing scientific curiosity mainly because of the lack of experimental structure information of the disordered shear bands, comprising light elements of carbon and boron only. Here we report the atomic structure of the amorphous shear bands in boron carbide characterized by state-of-the-art aberration-corrected transmission electron microscopy. Distorted icosahedra, displaced from the crystalline matrix, were observed in nano-sized amorphous bands that produce dislocation-like local shear strains. These experimental results provide direct experimental evidence that the formation of amorphous shear bands in boron carbide results from the disassembly of the icosahedra, driven by shear stresses.

Reddy KM; Liu P; Hirata A; Fujita T; Chen MW

2013-09-01

324

Atomic structure of amorphous shear bands in boron carbide.  

Science.gov (United States)

Amorphous shear bands are the main deformation and failure mode of super-hard boron carbide subjected to shock loading and high pressures at room temperature. Nevertheless, the formation mechanisms of the amorphous shear bands remain a long-standing scientific curiosity mainly because of the lack of experimental structure information of the disordered shear bands, comprising light elements of carbon and boron only. Here we report the atomic structure of the amorphous shear bands in boron carbide characterized by state-of-the-art aberration-corrected transmission electron microscopy. Distorted icosahedra, displaced from the crystalline matrix, were observed in nano-sized amorphous bands that produce dislocation-like local shear strains. These experimental results provide direct experimental evidence that the formation of amorphous shear bands in boron carbide results from the disassembly of the icosahedra, driven by shear stresses. PMID:24052052

Reddy, K Madhav; Liu, P; Hirata, A; Fujita, T; Chen, M W

2013-09-20

325

Atomic structure of amorphous shear bands in boron carbide  

Science.gov (United States)

Amorphous shear bands are the main deformation and failure mode of super-hard boron carbide subjected to shock loading and high pressures at room temperature. Nevertheless, the formation mechanisms of the amorphous shear bands remain a long-standing scientific curiosity mainly because of the lack of experimental structure information of the disordered shear bands, comprising light elements of carbon and boron only. Here we report the atomic structure of the amorphous shear bands in boron carbide characterized by state-of-the-art aberration-corrected transmission electron microscopy. Distorted icosahedra, displaced from the crystalline matrix, were observed in nano-sized amorphous bands that produce dislocation-like local shear strains. These experimental results provide direct experimental evidence that the formation of amorphous shear bands in boron carbide results from the disassembly of the icosahedra, driven by shear stresses.

Reddy, K. Madhav; Liu, P.; Hirata, A.; Fujita, T.; Chen, M. W.

2013-09-01

326

Supersonic Shear Instabilities in Astrophysical Boundary Layers  

CERN Multimedia

Disk accretion onto weakly magnetized astrophysical objects often proceeds via a boundary layer that forms near the object's surface, in which the rotation speed of the accreted gas changes rapidly. Here we study the initial stages of formation for such a boundary layer around a white dwarf or a young star by examining the hydrodynamical shear instabilities that may initiate mixing and momentum transport between the two fluids of different densities moving supersonically with respect to each other. We find that an initially laminar boundary layer is unstable to two different kinds of instabilities. One is an instability of a supersonic vortex sheet (implying a discontinuous initial profile of the angular speed of the gas) in the presence of gravity, which we find to have a growth rate of order (but less than) the orbital frequency. The other is a sonic instability of a finite width, supersonic shear layer, which is similar to the Papaloizou-Pringle instability. It has a growth rate proportional to the shear i...

Belyaev, Mikhail

2011-01-01

327

Singular eigenfunctions for shearing fluids I  

Energy Technology Data Exchange (ETDEWEB)

The authors construct singular eigenfunctions corresponding to the continuous spectrum of eigenvalues for shear flow in a channel. These modes are irregular as a result of a singularity in the eigenvalue problem at the critical layer of each mode. They consider flows with monotonic shear, so there is only a single critical layer for each mode. They then solve the initial-value problem to establish that these continuum modes, together with any discrete, growing/decaying pairs of modes, comprise a complete basis. They also view the problem within the framework of Hamiltonian theory. In that context, the singular solutions can be viewed as the kernel of an integral, canonical transformation that allows us to write the fluid system, an infinite-dimensional Hamiltonian system, in action-angle form. This yields an expression for the energy in terms of the continuum modes and provides a means for attaching a characteristic signature (sign) to the energy associate with each eigenfunction. They follow on to consider shear-flow stability within the Hamiltonian framework. Next, the authors show the equivalence of integral superpositions of the singular eigenfunctions with the solution derived with Laplace transform techniques. In the long-time limit, such superpositions have decaying integral averages across the channel, revealing phase mixing or continuum damping. Under some conditions, this decay is exponential and is then the fluid analogue of Landau damping. Finally, the authors discuss the energetics of continuum damping.

Balmforth, N.J.; Morrison, P.J.

1995-02-01

328

Shear Localization and Fracture in Shocked Metals  

Energy Technology Data Exchange (ETDEWEB)

Metals are used in structural engineering applications because they can yield and deform before they break. However, under certain conditions of dynamic loading, metals can fail prematurely. This behavior is often associated with shear localization phenomena, with a shear band acting as a precursor to crack formation. These phenomena have been observed in metals for some time, however modeling this behavior in a continuum simulation code has met with very limited success. We are pursuing a series of model experiments closely linked to new model development in order to gain a fundamental understanding of shear localization and fracture. Many NNSA and DoD related missions require modeling and simulation of the response of metals to high explosive (HE) loading and whether those metals fail or fracture. HE loading differs from the loading experienced by a specimen in a traditional engineering application. In HE loading, the first process to occur is the passage of a strong shock through the metal due to detonation. This shock completely changes the microstructure of the metal by inducing intense dislocation multiplication, sometimes accompanied by the formation of deformation twins. This change in microstructure strongly modifies the mechanical response of the metal, changing its yield strength, work hardening rate, and strain to failure. Only after this complete change of microstructure does the metal start to deform due to the velocity imparted by the shock and the further acceleration from the high pressure HE detonation gasses.

Becker, R; Belak, J; Campbell, G

2002-12-16

329

Micro-capsules in shear flow  

International Nuclear Information System (INIS)

This paper deals with flow-induced shape changes of elastic capsules. The state of the art concerning both theory and experiments is briefly reviewed starting with dynamically induced small deformation of initially spherical capsules and the formation of wrinkles on polymerized membranes. Initially non-spherical capsules show tumbling and tank-treading motion in shear flow. Theoretical descriptions of the transition between these two types of motion assuming a fixed shape are at odds with the full capsule dynamics obtained numerically. To resolve the discrepancy, we expand the exact equations of motion for small deformations and find that shape changes play a dominant role. We classify the dynamical phase transitions and obtain numerical and analytical results for the phase boundaries as a function of viscosity contrast, shear and elongational flow rate. We conclude with perspectives on time-dependent flow, on shear-induced unbinding from surfaces, on the role of thermal fluctuations and on applying the concepts of stochastic thermodynamics to these systems.

2011-05-11

330

Resonance shear measurement of nanoconfined ionic liquids.  

UK PubMed Central (United Kingdom)

Two types of imidazolium-based ionic liquid (IL), 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C(4)mim][NTF(2)]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([C(4)mim][BF(4)]), confined between silica surfaces were investigated by surface force apparatus (SFA)-based resonance shear measurements together with surface force measurements. The surface force profiles in the ILs showed oscillatory solvation forces below the characteristic surface separations: 10.0 nm for [C(4)mim][NTf(2)] and 6.9 nm for [C(4)mim][BF(4)]. The more pronounced solvation force found in [C(4)mim][NTf(2)] suggests that the crystal-forming ability of the IL contributes to the stronger layering of the ILs adjacent to the surface. The resonance shear measurement and the physical model analysis revealed that the viscosities of the confined ILs were 1-3 orders of magnitude higher than that of the bulk IL. This paper also focused on the correlation between the resonance shear behaviour and the lubrication property of the ILs, and the suspension rheology in the ILs. An understanding of the solid-IL interface and of ILs confined in nanospace will facilitate the further development of novel applications employing ILs.

Ueno K; Kasuya M; Watanabe M; Mizukami M; Kurihara K

2010-04-01

331

Resonance shear measurement of nanoconfined ionic liquids.  

Science.gov (United States)

Two types of imidazolium-based ionic liquid (IL), 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C(4)mim][NTF(2)]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([C(4)mim][BF(4)]), confined between silica surfaces were investigated by surface force apparatus (SFA)-based resonance shear measurements together with surface force measurements. The surface force profiles in the ILs showed oscillatory solvation forces below the characteristic surface separations: 10.0 nm for [C(4)mim][NTf(2)] and 6.9 nm for [C(4)mim][BF(4)]. The more pronounced solvation force found in [C(4)mim][NTf(2)] suggests that the crystal-forming ability of the IL contributes to the stronger layering of the ILs adjacent to the surface. The resonance shear measurement and the physical model analysis revealed that the viscosities of the confined ILs were 1-3 orders of magnitude higher than that of the bulk IL. This paper also focused on the correlation between the resonance shear behaviour and the lubrication property of the ILs, and the suspension rheology in the ILs. An understanding of the solid-IL interface and of ILs confined in nanospace will facilitate the further development of novel applications employing ILs. PMID:20379497

Ueno, Kazuhide; Kasuya, Motohiro; Watanabe, Masayoshi; Mizukami, Masashi; Kurihara, Kazue

2010-03-11

332

Horizontal Shear Wave Imaging of Large Optics  

Energy Technology Data Exchange (ETDEWEB)

When complete the National Ignition Facility (NIF) will be the world's largest and most energetic laser and will be capable of achieving for the first time fusion ignition in the laboratory. Detecting optics features within the laser beamlines and sizing them at diameters of 0.1 mm to 10 mm allows timely decisions concerning refurbishment and will help with the routine operation of the system. Horizontally polarized shear waves at 10 MHz were shown to accurately detect, locate, and size features created by laser operations from 0.5 mm to 8 mm by placing sensors at the edge of the optic. The shear wave technique utilizes highly directed beams. The outer edge of an optic can be covered with shear wave transducers on four sides. Each transducer sends a pulse into the optic and any damage reflects the pulse back to the transmitter. The transducers are multiplexed, and the collected time waveforms are enveloped and replicated across the width of the element. Multiplying the data sets from four directions produces a map of reflected amplitude to the fourth power, which images the surface of the optic. Surface area can be measured directly from the image, and maximum depth was shown to be correlated to maximum amplitude of the reflected waveform.

Quarry, M J

2007-09-05

333

High-shear-rate optical rheometer  

Science.gov (United States)

We have developed a parallel-plate rheometer in a magnetic-disk drive configuration constructed of optically transparent materials and operating with a very small gap for measurements at very high shear rates. The friction force at the disk-slider interface has been measured as a function of sliding speed while the film thickness was monitored in situ using a capacitance technique. The shear rate is calculated from the film thickness and the sliding speed. A thin film can be applied on the disk, which allows very high-shear-rate measurements at low sliding speeds with negligible viscous heating. Both disk and slider have been made of optically transparent material to allow optical measurements simultaneously with the rheological measurements. In the present mode, the apparatus is set up for simultaneous rheometery and birefringence measurements on a thin film of polymer lubricant. Rheology and birefringence measurements were made on a perfluoropolyether lubricant over a range of strain rate from 103 s-1 to greater than 106 s-1 with 800 nm, 400 nm, and 200 nm film thicknesses.

Mriziq, K. S.; Dai, H. J.; Dadmun, M. D.; Jellison, G. E.; Cochran, H. D.

2004-06-01

334

Fibre-reinforced plastic composites - Determination of the in-plane shear stress/shear strain response, including the in-plane shear modulus and strength, by the plus or minus 45 degree tension test method  

CERN Document Server

Fibre-reinforced plastic composites - Determination of the in-plane shear stress/shear strain response, including the in-plane shear modulus and strength, by the plus or minus 45 degree tension test method

International Organization for Standardization. Geneva

1997-01-01

335

Shear stress and advanced atherosclerosis in human coronary arteries.  

UK PubMed Central (United Kingdom)

The role of low and oscillating shear stress as a key factor for localizing early atherosclerotic plaques is generally accepted. Once more advanced plaques protrude into the lumen, the shear stress they are exposed to changes. The influence of shear stress on plaque composition in advanced atherosclerosis is not fully understood. In this review, we discuss our recent studies on the relationship between shear stress and plaque composition and the location of plaque rupture in human coronary arteries. We have shown that elevated shear stress levels can be found over plaques inducing only mild luminal narrowing and are not subjected to treatment. Regional exposure of certain plaque regions to high shear stress is therefore a condition that will pertain for a prolonged period of time. We have also shown that in more advanced atherosclerosis the necrotic core experiences higher shear stress. Low shear stress plaque regions can be found downstream of the plaque and are stiffer. High shear stress plaque regions can be found either at the upstream, shoulder or cap region of the plaque and are softer. The plaque regions with the highest strain levels are the regions that are exposed to the highest shear stress. The high shear stress plaque regions are the only plaque regions that get softer over time. Finally, high shear stress is also associated with the location of plaque rupture in non-culprit lesion in human coronary arteries. Combining our findings with data from literature, we can conclude that advanced coronary plaques grow in the distal regions. The distal plaque regions are exposed to low shear stress, are stiffer and have a stable plaque phenotype. The regions exposed to high shear stress are softer, and are associated with vulnerable plaque features.

Gijsen F; van der Giessen A; van der Steen A; Wentzel J

2013-01-01

336

Distribution functions of a simple fluid under shear. II. High shear rates  

International Nuclear Information System (INIS)

[en] The distortion of structure of a simple, inverse 12 soft-sphere fluid undergoing plane Couette flow is studied by nonequilibrium molecular dynamics (NEMD) and equilibrium molecular dynamics (EMD) with a high-shear-rate version of the nonequilibrium (NE) potential obtained recently from the NE distribution function theory of Gan and Eu [Phys. Rev. A 45, 3670; 46, 6344 (1992)]. The theory suggests a NE potential under which the equilibrium structure of the fluid is that of a NE fluid, and also suggests a corresponding Ornstein-Zernike equation with its closure relations. As in the low-shear-rate case [Yu. V. Kalyuzhnyi, S. T. Cui, P. T. Cummings, and H. D. Cochran, Phys. Rev. E 60, 1716 (1999)] the agreement between EMD and the modified hypernetted chain version of the theory is good. Although the high-shear-rate version of the NE potential improves the agreement between NEMD and EMD results (in comparison with the low-shear-rate version), its predictions are still unsatisfactory. With the high-shear-rate NE potential, EMD gives qualitatively correct predictions only for the shift of the position of the first maximum of the NE distribution function. The corresponding changes in the magnitude of the first maximum predicted by EMD have an opposite direction in comparison with those predicted by NEMD. It is concluded that the NE potential used is not very successful, and more accurate models for the potential are needed

2001-01-01

337

Distribution functions of a simple fluid under shear. II. High shear rates  

Energy Technology Data Exchange (ETDEWEB)

The distortion of structure of a simple, inverse 12 soft-sphere fluid undergoing plane Couette flow is studied by nonequilibrium molecular dynamics (NEMD) and equilibrium molecular dynamics (EMD) with a high-shear-rate version of the nonequilibrium (NE) potential obtained recently from the NE distribution function theory of Gan and Eu [Phys. Rev. A 45, 3670; 46, 6344 (1992)]. The theory suggests a NE potential under which the equilibrium structure of the fluid is that of a NE fluid, and also suggests a corresponding Ornstein-Zernike equation with its closure relations. As in the low-shear-rate case [Yu. V. Kalyuzhnyi, S. T. Cui, P. T. Cummings, and H. D. Cochran, Phys. Rev. E 60, 1716 (1999)] the agreement between EMD and the modified hypernetted chain version of the theory is good. Although the high-shear-rate version of the NE potential improves the agreement between NEMD and EMD results (in comparison with the low-shear-rate version), its predictions are still unsatisfactory. With the high-shear-rate NE potential, EMD gives qualitatively correct predictions only for the shift of the position of the first maximum of the NE distribution function. The corresponding changes in the magnitude of the first maximum predicted by EMD have an opposite direction in comparison with those predicted by NEMD. It is concluded that the NE potential used is not very successful, and more accurate models for the potential are needed.

Kalyuzhnyi, Yu. V.; Cui, S. T.; Cochran, H. D.

2001-01-01

338

Shear flow effect on ion temperature gradient vortices in plasmas with sheared magnetic field  

DEFF Research Database (Denmark)

The effect of velocity shear on ion temperature gradient (ITG) driven vortices in a nonuniform plasma in a curved, sheared magnetic field is investigated. In absence of parallel ion dynamics, vortex solutions for the ITG mode are studied analytically. It is shown that under certain conditions the coupled equations for potential and pressure exhibit special tripolar vortex-like structures. For the general case, however, parallel ion dynamics is included and the equation describing the stationary ITG vortex has the structure of a nonlinear Poisson-type equation. Analytical as well as numerical solutions of this equation are presented for various possible cases. It is shown that, for a critical value of the velocity shear asymmetric dipolar vortices can arise which are strongly modified as a localized vortex chain at resonance. For strong velocity shear these structures are destroyed and ultimately lead to a dominating monopolar form. The effects of magnetic shear indicate it may destroy these structures. (C) 1999 American Institute of Physics.

Chakrabarti, N.; Juul Rasmussen, J.

1999-01-01

339

Loss of solutions in shear banding fluids in shear banding fluids driven by second normal stress differences  

CERN Document Server

Edge fracture occurs frequently in non-Newtonian fluids. A similar instability has often been reported at the free surface of fluids undergoing shear banding, and leads to expulsion of the sample. In this paper the distortion of the free surface of such a shear banding fluid is calculated by balancing the surface tension against the second normal stresses induced in the two shear bands, and simultaneously requiring a continuous and smooth meniscus. We show that wormlike micelles typically retain meniscus integrity when shear banding, but in some cases can lose integrity for a range of average applied shear rates during which one expects shear banding. This meniscus fracture would lead to ejection of the sample as the shear banding region is swept through. We further show that entangled polymer solutions are expected to display a propensity for fracture, because of their much larger second normal stresses. These calculations are consistent with available data in the literature. We also estimate the meniscus di...

Skorski, Stanislav

2011-01-01

340

Probing Shear-Banding Transitions of Entangled Liquids Using Large Amplitude Oscillatory Shearing (LAOS) Deformations  

Science.gov (United States)

We explore the dynamical response, under Large Amplitude Oscillatory Shear (LAOS) deformation, of a new class of constitutive models (denoted generically VCM) designed to describe entangled solutions of wormlike micellar solutions or concentrated polymer solutions. The goal is to investigate the applicability of LAOS as a test protocol for determining the rheological properties of entangled fluids and the onset of shear banding events that are observed experimentally. The VCM family of models show that shear-banding transitions will develop in LAOS experiments at a frequency-dependent critical strain. The velocity and stress field exhibit a complex dynamical response that varies with both the frequency and amplitude of the forcing. The rheological response of the different states that are observed can be represented in terms of a Pipkin diagram together with Lissajous figures (phase plane portraits).

Zhou, Lin; Ewoldt, Randy H.; Cook, L. Pamela; McKinley, Gareth H.

2008-07-01

 
 
 
 
341

Study of punching shear in arctic offshore structures  

Energy Technology Data Exchange (ETDEWEB)

Experimental and analytical studies of punching shear in reinforced and prestressed concrete slabs and shells were performed to gain an increased understanding of the mechanism of punching shear failures in offshore structures for the Arctic. The test specimens of this project were 1/6-scale models of sections of typical perimeter walls with flat and curved configurations. Shear reinforcement was provided in the specimens with headed shear bars. The main variables investigated in the program were: the amount of shear reinforcement, curvature, prestressing, and span-continuity condition. The addition of shear reinforcement resulted in significant increases in punching shear strengths, particularly in the plate specimens. The presence of curvature in the shell specimens produced large increases in punching shear strength. An apparent upper limit on punching shear strength was reached in the shell specimens with shear reinforcement whereby the concrete rather than the reinforcement controlled the failure mechanism. Effects of prestressing in the specimens were inconclusive. The single-span plate specimen was stronger than the similar three-span plate specimen.

McLean, D.I.

1987-01-01

342

Evolution of thermal ion transport barriers in reversed shear/optimised shear plasmas  

International Nuclear Information System (INIS)

[en] The effects of the magnetic and ExB rotation shears on the thermal ion transport in advanced tokamak scenarios are analyzed through the predictive modelling of the evolution of internal transport barriers. Such a modelling is performed with an experimentally validated L-mode thermal diffusivity completed with a semi-empirical shear correction which is based on simple theoretical arguments from turbulence studies. A multi-machine test of the model on relevant discharges from the ITER Data Base (TFTR, DIII-D and JET) is presented. (author)

1999-01-01

343

New method of measuring multigrade oil-shear elasticity and viscosity at high shear rates  

Energy Technology Data Exchange (ETDEWEB)

Recent journal-bearing oil-film thickness data (1) strongly suggest that, in order to develop minimum-viscosity multigrade oils for maximizing fuel economy, it is not enough to examine viscosity n alone, it is essential also to examine a certain kind of shear elasticity, of which one measure is the first normal stress difference N1 in shear flow. Within a group of isoviscous multigrade oils, N1 values can differ significantly; for 10W-40 and 15W-40 oils, an average of 75% of the minimum oil-film thickness can be attributed to N1.

Lodge, A.S.

1987-01-01

344

Dynamic Deformation and Recovery Response of Red Blood Cells to a Cyclically Reversing Shear Flow: Effects of Frequency of Cyclically Reversing Shear Flow and Shear Stress Level  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dynamic deformation and recovery responses of red blood cells (RBCs) to a cyclically reversing shear flow generated in a 30-?m clearance, with the peak shear stress of 53, 108, 161, and 274 Pa at the frequency of 1, 2, 3, and 5 Hz, respectively, were studied. The RBCs' time-varying velocity varied a...

Watanabe, Nobuo; Kataoka, Hiroyuki; Yasuda, Toshitaka; Takatani, Setsuo

345

Bulk flows, shear, and the great attractor  

Energy Technology Data Exchange (ETDEWEB)

The predictions of cold-dark-matter (CDM) cosmological models regarding the distance to the great attractor and galaxy formation in the early universe are evaluated by means of comparisons based on a statistical analysis of the elliptical galaxy sample of Dressler et al. (1987). The focus is on the ratio of bulk flow speed to velocity shear. It is found that all of the models yield a broad distribution of distances, with no evidence for an underprediction of large-scale power by the CDM theory. Any discrepancy between CDM models and observations is shown to lie in the normalization required rather than in the power-spectrum shape. 15 refs.

Kaiser, N. (Toronto Univ. (Canada))

1991-01-01

346

The SDSS Coadd: Cosmic Shear Measurement  

CERN Multimedia

Stripe 82 in the Sloan Digital Sky Survey was observed multiple times, allowing deeper images to be constructed by coadding the data. Here we analyze the ellipticities of background galaxies in this 275 square degree region, searching for evidence of distortions due to cosmic shear. The E-mode is detected in both real and Fourier space with $>5$-$\\sigma$ significance on degree scales, while the B-mode is consistent with zero as expected. The amplitude of the signal constrains the combination of the matter density $\\Omega_m$ and fluctuation amplitude $\\sigma_8$ to be $\\Omega_m^{0.7}\\sigma_8 = 0.276^{+0.036}_{-0.050}$.

Lin, Huan; Seo, Hee-Jong; Soares-Santos, Marcelle; Annis, James; Hao, Jiangang; Johnston, David; Kubo, Jeffrey M; Reis, Ribamar R R; Simet, Melanie

2011-01-01

347

Transient growth in a shearing stratified atmosphere  

CERN Document Server

The stability of fully compressible isothermal shear flows is studied in response to recent claims that such flows could be locally unstable to a linear instability. The behavior of the solution is characterized by the time-dependent Rayleigh quotient, which lies between the smallest and the largest eigenvalue. The imaginary part of the Rayleigh quotient (corresponding to a growth rate) is, for different initial conditions, always found to approach zero provided the flow is Rayleigh stable (angular momentum increasing outwards). The real part (corresponding to frequency) is usually growing linearly in time, which reflects the progressive increase in wavenumber for horizontally propagating sound waves.

Brandenburg, A; Brandenburg, Axel; Dintrans, Boris

2001-01-01

348

Relativistic shear-free fluids with symmetry  

CERN Multimedia

We study the complete conformal geometry of shear-free spacetimes with spherical symmetry and do not specify the form of the matter content. The general conformal Killing symmetry is solved and we can explicitly exhibit the vector. The existence of a conformal symmetry places restrictions on the model. The conditions on the gravitational potentials are expressed as a system of integrability conditions. Timelike sectors and inheriting conformal symmetry vectors, which map fluid flow lines conformally onto fluid flow lines, are generated and the integrability conditions are shown to be satisfied. As an example, a spacetime, which is expanding and accelerating, is identified which contains a spherically symmetric conformal symmetry.

Moopanar, S

2013-01-01

349

Buckling of shear loading plates with strengthenings  

Energy Technology Data Exchange (ETDEWEB)

The paper treats the influence of either weakening or strengthening of rectangular plates on the critical external buckling load. The plate geometry was chosen so that the buckling process takes place in the elastic range. The simply supported plate is loaded with shear forces per unit length which act on its edges. The results present the buckling coefficient as a function of the ratio between the thickness of the weakening or strengthening and the initial plate. The buckling coefficient is analyzed as a function of the ratio between the weight of the weakened or strengthened plate and the initial plate weight without weakening or strengthening too. (orig.)

Kosel, F.; Petrisic, J. [Ljubljana Univ. (Slovenia). Fakulteta za Strojnistvo

2000-07-01

350

Shearing radiative collapse with expansion and acceleration  

CERN Document Server

We investigate the behaviour of a relativistic spherically symmetric radiative star with an accelerating, expanding and shearing interior matter distribution in the presence of anisotropic pressures. The junction condition can be written in standard form in three cases: linear, Bernoulli and Riccati equations. We can integrate the boundary condition in each case and three classes of new solutions are generated. For particular choices of the metric we investigate the physical properties and consider the limiting behaviour for large values of time. The causal temperature can also be found explicitly.

Thirukkanesh, S; Maharaj, S D

2013-01-01

351

Nonequilibrium steady states in sheared binary fluids  

CERN Multimedia

We simulate by lattice Boltzmann the steady shearing of a binary fluid mixture undergoing phase separation with full hydrodynamics in two dimensions. Contrary to some theoretical scenarios, a dynamical steady state is attained with finite domain lengths $L_{x,y}$ in the directions ($x,y)$ of velocity and velocity gradient. Apparent scaling exponents are estimated as $L_{x}\\sim\\dot{\\gamma}^{-2/3}$ and $L_{y}\\sim\\dot{\\gamma}^{-3/4}$. We discuss the relative roles of diffusivity and hydrodynamics in attaining steady state.

Stansell, P; Desplat, J C; Adhikari, R; Cates, M E

2005-01-01

352

Nonequilibrium fluctuations of an interface under shear.  

UK PubMed Central (United Kingdom)

The steady-state properties of an interface in a stationary Couette flow are addressed within the framework of fluctuating hydrodynamics. Our study reveals that thermal fluctuations are driven out of equilibrium by an effective shear rate that differs from the applied one. In agreement with experiments, we find that the mean-square displacement of the interface is reduced by the flow. We also show that nonequilibrium fluctuations present a certain degree of universality in the sense that all features of the fluids can be factorized into a single control parameter. Finally, the results are discussed in the light of recent experimental and numerical studies.

Thiébaud M; Bickel T

2010-03-01

353

Propagation of waves in shear flows  

CERN Multimedia

The state of the art in a theory of oscillatory and wave phenomena in hydrodynamical flows is presented in this book. A unified approach is used for waves of different physical origins. A characteristic feature of this approach is that hydrodynamical phenomena are considered in terms of physics; that is, the complement of the conventionally employed formal mathematical approach. Some physical concepts such as wave energy and momentum in a moving fluid are analysed, taking into account induced mean flow. The physical mechanisms responsible for hydrodynamic instability of shear flows are conside

Fabrikant, A L

1998-01-01

354

Interface instability in shear banding flow  

CERN Document Server

We report on the spatio-temporal dynamics of the interface in shear-banding flow of a wormlike micellar system (cetyltrimethylammonium bromide and sodium nitrate in water) during a start-up experiment. Using the scattering properties of the induced structures, we demonstrate the existence of an instability of the interface between bands along the vorticity direction. Different regimes of spatio-temporal dynamics of the interface are indentified along the stress plateau. We build a model based on the flow symetry which qualitatively describes the observed patterns.

Lerouge, S; Decruppe, J P

2006-01-01

355

Brownian forces in sheared granular matter.  

UK PubMed Central (United Kingdom)

We present results from a series of experiments on a granular medium sheared in a Couette geometry and show that their statistical properties can be computed in a quantitative way from the assumption that the resultant from the set of forces acting in the system performs a Brownian motion. The same assumption has been utilized, with success, to describe other phenomena, such as the Barkhausen effect in ferromagnets, and so the scheme suggests itself as a more general description of a wider class of driven instabilities.

Baldassarri A; Dalton F; Petri A; Zapperi S; Pontuale G; Pietronero L

2006-03-01

356

Flexure of thick orthotropic plates by exponential shear deformation theory  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english In the present paper, a variationally consistent exponential shear deformation theory taking into account transverse shear deformation effect is presented for the flexural analysis of thick orthotropic plates. The inplane displacement field uses exponential function in terms of thickness coordinate to include the shear deformation effect. The transverse shear stress can be obtained directly from the constitutive relations satisfying the shear stress free surface condition (more) s on the top and bottom surfaces of the plate, hence the theory does not require shear correction factor. Governing equations and boundary conditions of the theory are obtained using the principle of virtual work. Results obtained for static flexure of simply supported orthotropic plates are compared with those of other refined theories and elasticity solution wherever applicable. The results obtained by present theory are in excellent agreement with those of exact results and other higher order theories. Thus the efficacy of the present refined theory is established.

Sayyad, A. S.

2013-05-01

357

Discontinuous shear thickening of frictional hard-sphere suspensions  

CERN Multimedia

Discontinuous Shear Thickening (DST) observed in many dense athermal suspensions has proven difficult to understand and to reproduce numerically. By introducing a numerical scheme including both relevant hydrodynamic interactions and granular-like contacts, we show that contact friction is essential for having DST. Above a critical volume fraction, we observe the existence of two states: a low viscosity, contactless (hence frictionless) state, and a high viscosity frictional shear jammed state. These two states are separated by a critical shear stress, associated with a critical shear rate where DST occurs. The shear jammed state is reminiscent of the jamming phase of granular matter. Continuous Shear Thickening is seen as a lower volume fraction vestige of the jamming transition.

Seto, Ryohei; Morris, Jeffrey F; Denn, Morton M

2013-01-01

358

Shear dispersion and turbulence decorrelation by differential rotation  

DEFF Research Database (Denmark)

The shear enhanced dispersion of a passive scalar field subject to differential rotation is investigated analytically and interpretations are given in terms of turbulence shear decorrelation. Using the method of advected coordinates, the enhanced dispersion caused by steady and oscillatory flows with uniform shear is derived and the well-known turbulence shear decorrelation theory is recovered. The additional role of kinetic energy transfer due to differential advection of vorticity is also pointed out. Finally, the shear enhanced dispersion due to flows with periodic variations in space as well as time is given. It is found that radially alternating flows may significantly reduce the turbulence decorrelation time provided the root mean square flow shear is larger than the flow oscillation frequency. In the opposite limit of fast flow oscillations there is no turbulence decorrelation. (C) 2005 American Institute of Physics.

Garcia, O.E.; Bian, N.H.

2005-01-01

359

dc-Magnetic-Field Generation in Unmagnetized Shear Flows  

Science.gov (United States)

The generation of dc magnetic fields in unmagnetized electron-ion shear flows is shown to be associated to either initial thermal effects or the onset of electron-scale shear instabilities, in particular the cold Kelvin-Helmholtz instability. This mechanism, intrinsic to shear gradients on the electron scale, is described through a kinetic model that predicts the growth and the saturation of the dc field in both scenarios. The theoretical results are confirmed by multidimensional particle-in-cell simulations, demonstrating the formation of long-lived magnetic fields (t˜100’s?pi-1) along the full longitudinal extent of the shear layer, with a typical transverse width of ?0c/?pe, reaching magnitudes eBdc/mec?pe˜?0?0 for an initial sharp shear. The case of an initial smooth shear is also discussed.

Grismayer, T.; Alves, E. P.; Fonseca, R. A.; Silva, L. O.

2013-07-01

360

Suppressing van der Waals driven rupture through shear  

Science.gov (United States)

A thin viscous film on a substrate is susceptible to rupture instabilities driven by van der Waals attractions. When a sufficiently large shear is applied to the free surface, the rupture instability is suppressed in two dimensions for sufficiently large shear magnitude and replaced by a permanent finite amplitude travelling wave with speed approximately equal to the speed of the surface. For small amplitudes, the wave is governed by the Kuramoto-Sivashinsky equation. If three- dimensional disturbances are allowed, the shear is decoupled from perpendicular disturbances to the flow, and line rupture would occur. In this case, replacing the unidirectional shear with a rotating shear can suppress rupture for suitable choices of shear magnitude and angular velocity.

Davis, Michael; Gratton, Michael; Davis, Stephen

2010-11-01

 
 
 
 
361

Microalga propels along vorticity direction in a shear flow  

Science.gov (United States)

Using high-speed digital holographic microscopy and microfluidics, we discover that, when encountering fluid flow shear above a threshold, unicellular green alga Dunaliella primolecta migrates unambiguously in the cross-stream direction that is normal to the plane of shear and coincides with the local fluid flow vorticity. The flow shear drives motile microalgae to collectively migrate in a thin two-dimensional horizontal plane and consequently alters the spatial distribution of microalgal cells within a given suspension. This shear-induced algal migration differs substantially from periodic rotational motion of passive ellipsoids, known as Jeffery orbits, as well as gyrotaxis by bottom-heavy swimming microalgae in a shear flow due to the subtle interplay between torques generated by gravity and viscous shear. Our findings could facilitate mechanistic solutions for modeling planktonic thin layers and sustainable cultivation of microalgae for human nutrition and bioenergy feedstock.

Chengala, Anwar; Hondzo, Miki; Sheng, Jian

2013-05-01

362

Microalga propels along vorticity direction in a shear flow.  

UK PubMed Central (United Kingdom)

Using high-speed digital holographic microscopy and microfluidics, we discover that, when encountering fluid flow shear above a threshold, unicellular green alga Dunaliella primolecta migrates unambiguously in the cross-stream direction that is normal to the plane of shear and coincides with the local fluid flow vorticity. The flow shear drives motile microalgae to collectively migrate in a thin two-dimensional horizontal plane and consequently alters the spatial distribution of microalgal cells within a given suspension. This shear-induced algal migration differs substantially from periodic rotational motion of passive ellipsoids, known as Jeffery orbits, as well as gyrotaxis by bottom-heavy swimming microalgae in a shear flow due to the subtle interplay between torques generated by gravity and viscous shear. Our findings could facilitate mechanistic solutions for modeling planktonic thin layers and sustainable cultivation of microalgae for human nutrition and bioenergy feedstock.

Chengala A; Hondzo M; Sheng J

2013-05-01

363

Shear stress induced stimulation of mammalian cell metabolism.  

UK PubMed Central (United Kingdom)

A flow apparatus has been developed for the study of the metabolic response of anchorage-dependent cells to a wide range of steady and pulsatile shear stresses under well-controlled conditions. Human umbilical vein endothelial cell monolayers were subjected to steady shear stresses of up to 24 dynes/cm(2), and the production of prostacyclin was determined. The onset of flow led to a burst in prostacyclin production which decayed to a long term steady state rate (SSR). The SSR of cells exposed to flow was greater than the basal release level, and increased linearly with increasing shear stress. This study demonstrates that shear stress in certain ranges may not be detrimental to mammalian cell metabolism. In fact, throughout the range of shear stresses studied, metabolite production is maximized by maximizing shear stress.

Frangos JA; McIntire LV; Eskin SG

1988-10-01

364

Microscopic Mechanism of Shear Bands in Amorphous Solids  

Science.gov (United States)

The fundamental instability responsible for the shear localization which results in shear bands in amorphous solids remains unknown despite an enormous amount of research, both experimental and theoretical. As this is the main mechanism for the failure of metallic glasses, understanding the instability is invaluable in finding how to stabilize such materials against the tendency to shear localize. In this Letter we explain the mechanism for shear localization under shear, which is the appearance of highly correlated lines of Eshelby-like quadrupolar singularities which organize the nonaffine plastic flow of the amorphous solid into a shear band. We prove analytically that such highly correlated solutions in which N quadrupoles are aligned with equal orientations are minimum energy states when the strain is high enough. The line lies at 45 degrees to the compressive stress.

Dasgupta, Ratul; Hentschel, H. George E.; Procaccia, Itamar

2012-12-01

365

Microscopic mechanism of shear bands in amorphous solids.  

UK PubMed Central (United Kingdom)

The fundamental instability responsible for the shear localization which results in shear bands in amorphous solids remains unknown despite an enormous amount of research, both experimental and theoretical. As this is the main mechanism for the failure of metallic glasses, understanding the instability is invaluable in finding how to stabilize such materials against the tendency to shear localize. In this Letter we explain the mechanism for shear localization under shear, which is the appearance of highly correlated lines of Eshelby-like quadrupolar singularities which organize the nonaffine plastic flow of the amorphous solid into a shear band. We prove analytically that such highly correlated solutions in which N quadrupoles are aligned with equal orientations are minimum energy states when the strain is high enough. The line lies at 45 degrees to the compressive stress.

Dasgupta R; Hentschel HG; Procaccia I

2012-12-01

366

Transport Bifurcation Induced by Sheared Toroidal Flow in Tokamak Plasmas  

CERN Multimedia

First-principles numerical simulations are used to describe a transport bifurcation in a differentially rotating tokamak plasma. Such a bifurcation is more probable in a region of zero magnetic shear, where the component of the sheared toroidal flow that is perpendicular to the magnetic field has the strongest suppressing effect on the turbulence, than one of finite magnetic shear. Where the magnetic shear is zero, there are no growing linear eigenmodes at any finite value of flow shear. However, subcritical turbulence can be sustained, owing to the transient growth of modes driven by the ion temperature gradient (ITG) and the parallel velocity gradient (PVG). Nonetheless, in a parameter space containing a wide range of temperature gradients and velocity shears, there is a sizeable window where all turbulence is suppressed. Combined with the relatively low transport of momentum by collisional (neoclassical) mechanisms, this produces the conditions for a bifurcation from low to high temperature and velocity gr...

Highcock, E G; Parra, F I; Schekochihin, A A; Roach, C M; Cowley, S C

2011-01-01

367

On the nature of the shear viscosity and shear modulus relaxation in metallic glasses.  

Science.gov (United States)

Analysis of independent isothermal and linear heating creep and shear modulus measurements performed on bulk Pd- and Zr-based metallic glasses provides evidence that the relaxation of their viscoelastic and elastic properties is controlled by 'defects', which respond to stress and temperature similarly to dumbbell interstitials in simple crystalline metals. PMID:23899581

Tsyplakov, A N; Khonik, V A; Makarov, A S; Mitrofanov, Yu P; Afonin, G V; Kobelev, N P; Konchakov, R A; Lysenko, A V

2013-07-31

368

Strengthening of flat slabs against punching shear using post-installed shear reinforcement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A significant number of existing flat slabs currently require strengthening against punching shear for safety reasons (the increase of applied loads and deficiencies during design or construction) or to comply with more stringent code requirements. Available strengthening methods are, however, not c...

Fernández Ruiz, Miguel; Muttoni, Aurelio; Kunz

369

New provisions for punching shear in Model Code 2010 based on the Critical Shear Crack Theory  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The provisions for punching shear around concentrated loads in the new Model Code 2010 (MC2010) have been updated, covering a large number of design cases such as slabs with and without transverse reinforcement, different column/slab geometries and prestressed slabs amongst others. The theoretical f...

Sagaseta, Juan; Tassinari, Luca; Muttoni, Aurelio; Fernández Ruiz, Miguel

370

On the nature of the shear viscosity and shear modulus relaxation in metallic glasses.  

UK PubMed Central (United Kingdom)

Analysis of independent isothermal and linear heating creep and shear modulus measurements performed on bulk Pd- and Zr-based metallic glasses provides evidence that the relaxation of their viscoelastic and elastic properties is controlled by 'defects', which respond to stress and temperature similarly to dumbbell interstitials in simple crystalline metals.

Tsyplakov AN; Khonik VA; Makarov AS; Mitrofanov YP; Afonin GV; Kobelev NP; Konchakov RA; Lysenko AV

2013-08-01

371

Instabilities in Pulsating Pipe Flow of Shear-Thinning and Shear-Thickening Fluids  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, we have considered the modal and non-modal stability of fluids with shear-dependent viscosity flowing in a rigid straight pipe. A second order finite-difference code is used for the simulation of pipe flow in the cylindrical coordinate system. The Carreau-Yasuda model where the rheolo...

Sadrizadeh, Sasan

372

On the nature of the shear viscosity and shear modulus relaxation in metallic glasses  

Science.gov (United States)

Analysis of independent isothermal and linear heating creep and shear modulus measurements performed on bulk Pd- and Zr-based metallic glasses provides evidence that the relaxation of their viscoelastic and elastic properties is controlled by ‘defects’, which respond to stress and temperature similarly to dumbbell interstitials in simple crystalline metals.

Tsyplakov, A. N.; Khonik, V. A.; Makarov, A. S.; Mitrofanov, Yu P.; Afonin, G. V.; Kobelev, N. P.; Konchakov, R. A.; Lysenko, A. V.

2013-08-01

373

Shear zones between rock units with no relative movement  

DEFF Research Database (Denmark)

Shear zones are normally viewed as relatively narrow deformation zones that accommodate relative displacement between two "blocks" that have moved past each other in opposite directions. This study reports localized zones of shear between adjacent blocks that have not moved past each other. Such deformation zones, which we call wakes, form due to the movement of exotic blocks within a viscous medium (denser blocks sinking within a salt structure, (the paths) between separated boudins), melt in partially molten surroundings (melt movement during migmatisation), or solid blocks sinking through a partially molten magma body (stoping). From the fluid dynamics perspective these shear zones can be regarded as low Reynolds number deformation zones within the wake of a body moving through a viscous medium. While compact moving bodies (aspect ratio 1:1:1) generate axial symmetric (cone like) shear zones or wakes, elongated bodies (vertical plates or horizontal rod-like bodies) produce tabular shear zones or wakes. Unlike conventional shear zones across which shear indicators usually display consistent symmetries, shear indicators on either side of the shear zone or wake reported here show reverse kinematics. Thus profiles exhibit shear zones with opposed senses of movement across their center-lines or -planes.We have used field observations and results from analytical and numerical models to suggest that examples of wakes are the transit paths that develop where denser blocks sink within salt structures, bodies of melt rise through migmatites, between boudins separated by progressive extension and (perhaps) where slabs of subducted oceanic lithosphere delaminate from the continental crust and sink into the asthenosphere. We also argue that such shear zones may be more common than they have been given credit for and may be responsible for some reverse kinematics reported in shear zones.

Koyi, Hemin; Schmeling, Harro

2013-01-01

374

A transport bifurcation model for enhanced confinement with negative shear  

International Nuclear Information System (INIS)

[en] A magnetic shear driven transport bifurcation model for transition to enhanced confinement regime with negative shear and neutral beams is proposed. Strong fueling by high power beams leads to peaking of pressure profile and generation of large bootstrap current. The resulting negative shear reduces the growth of fluctuations. The transition to enhanced confinement regime occurs when fluctuations are completely quenched. Relevance of this to recent results from TFTR is briefly discussed. (author)

1997-01-01

375

The role of shear in the cosmological distance  

International Nuclear Information System (INIS)

The effect of shear along light rays on the distance-redshift relation in an inhomogeneous universe is investigated on the basis of relativistic optical equations. With some reasonable assumptions, an analytic formula for the shear in a simplified cosmological model is derived. We compare the derived formula with numerical calculations and discuss the validity and limitation of our formula. Then the role of shear in the distance-redshift relation is discussed in detail. (author).

1990-01-01

376

Inplane shear capacity of reinforced composite masonry block walls  

International Nuclear Information System (INIS)

[en] The objective of this paper is to describe a test program performed to determine the inplane shear capacity, stiffness and ductility of composite masonry walls subjected to earthquake type loadings. Specimens were simultaneously subjected to a range of compressive loads to simulate dead load; and inplane shear loads with full load reversal to simulate the earthquake cycling load. The influence of horizontal and vertical reinforcing steel percentages on the inplane shear capacity, stiffness and ductility was also investigated. (orig./HP)

1981-08-21

377

Shear-free gravitational collapse is strongly censored  

CERN Multimedia

We consider spherically symmetric spacetimes with matter whose timelike flow is assumed to be shear-free. A number of results on the formation and visibility of spacetime singularities is proven, with the main one being that shear-free collapse cannot admit locally naked singularities (which implies absence of globally naked singularities). We conjecture that shear is a necessary condition for the occurrence of locally naked singularities in generic gravitational collapse.

Gonçalves, S M C V

2004-01-01

378

Meat quality, proximate composition and muscle fatty acid profile of young llamas (Lama glama) supplemented with hay or concentrate during the dry season.  

Science.gov (United States)

Thirty llamas were used to study the effect of a 90day feed supplementation on meat quality, chemical composition and muscle fatty acid profile. Treatments were: GR=llama on native pasture until slaughter; GR+SH=like GR, but with overnight free access to barley/alfalfa hay; and GR+SC=like GR, but with overnight free access to a wheat bran/sorghum grain concentrate. The supplementation had no effect on postmortem pH and temperature decline in the Longissimus lumborum muscle (LLM), cooking losses nor Warner-Bratzler shear force values (P>0.05). Meat from GR+SC llama had higher fat content in LLM (P<0.05) compared to GR and GR+SH llama. Intramuscular fat from GR+SH llama showed higher (P<0.01) proportions of polyunsaturated fatty acids, higher (P<0.05) polyunsaturated fatty acids/saturated fatty acids and desirable fatty acids ratio, lower (P<0.05) omega-6/omega-3 (n-6/n-3) ratio, and higher (P<0.01) conjugated linoleic acid. PMID:23973566

Mamani-Linares, L W; Gallo, C B

2013-07-29

379

Relationship between temperament with performance and meat quality of feedlot steers with predominantly Charolais or Nellore breed  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The relation between temperament with performance and meat quality was determined in 79 Charolais × Nellore steers kept in feedlot. Temperament was evaluated according to exit velocity, scale composite score and flight distance four times in the finishing phase, along with body weight, intake and feed conversion measures. Cattle were classified as calm, intermediate and excited according to exit velocity measures at the beginning of the trial. Excited cattle presented la (more) rger values for composite score and flight distance. Irrespective of genotype, excited cattle presented lower average daily gain, dry matter intake and worse feed conversion. Temperament categories did not affect most of beef quality traits, except for calm Bos indicus steers, which presented greater pH measured 1 hour post mortem compared with more reactive steers. However, moderate but negative correlations were detected between exit velocity, flight distance and composite score and beef quality as well as Warner-Bratzler shear value, luminosity, pH measured 24 hours post mortem, although they were not consistent between genotypes raised under the same conditions.

Silveira, Isabella Dias Barbosa; Fischer, Vivian; Farinatti, Luis Henrique Ebling; Restle, João; Alves Filho, Dari Celestino; Menezes, Luís Fernando Glasenapp de

2012-06-01

380

Meat quality, proximate composition and muscle fatty acid profile of young llamas (Lama glama) supplemented with hay or concentrate during the dry season.  

UK PubMed Central (United Kingdom)

Thirty llamas were used to study the effect of a 90day feed supplementation on meat quality, chemical composition and muscle fatty acid profile. Treatments were: GR=llama on native pasture until slaughter; GR+SH=like GR, but with overnight free access to barley/alfalfa hay; and GR+SC=like GR, but with overnight free access to a wheat bran/sorghum grain concentrate. The supplementation had no effect on postmortem pH and temperature decline in the Longissimus lumborum muscle (LLM), cooking losses nor Warner-Bratzler shear force values (P>0.05). Meat from GR+SC llama had higher fat content in LLM (P<0.05) compared to GR and GR+SH llama. Intramuscular fat from GR+SH llama showed higher (P<0.01) proportions of polyunsaturated fatty acids, higher (P<0.05) polyunsaturated fatty acids/saturated fatty acids and desirable fatty acids ratio, lower (P<0.05) omega-6/omega-3 (n-6/n-3) ratio, and higher (P<0.01) conjugated linoleic acid.

Mamani-Linares LW; Gallo CB

2014-01-01

 
 
 
 
381

Effect of forage to concentrate ratio on growth performance, and on carcass and meat quality of Podolian young bulls.  

UK PubMed Central (United Kingdom)

The effect of forage to concentrate ratio: 60-40 [high concentrate group (HC) and 70-30 [low concentrate group (LC)] on growth, slaughtering performance and meat quality were evaluated in twenty organically farmed Podolian young bulls. Meat quality characteristics were measured on three different muscles [Longissimus dorsi (LD), Semimembranosus (SM) Semitendinosus (ST)], vacuum-packaged and chilled stored at 2-4 degrees C for 15 days. The animals in the HC group had higher weight gain than those in the LC group (P < 0.05). Slaughter data were not influenced by ration composition. The higher forage to concentrate ratio produced an improvement in fatty acid composition of the three muscles, with a higher polyunsaturated to saturated ratio (P < 0.001). Vitamin E and malondialdehyde (MDA) contents were not affected by the feeding treatment. Panel scores for tenderness and flavour (P < 0.01) and Warner-Bratzler Shear force (P < 0.001) were significantly affected by muscle, the LD muscle being the most tender and the richest in flavour but they not affected by dietary treatment.

Marino R; Albenzio M; Girolami A; Muscio A; Sevi A; Braghieri A

2006-03-01

382

Effect of forage to concentrate ratio on growth performance, and on carcass and meat quality of Podolian young bulls.  

Science.gov (United States)

The effect of forage to concentrate ratio: 60-40 [high concentrate group (HC) and 70-30 [low concentrate group (LC)] on growth, slaughtering performance and meat quality were evaluated in twenty organically farmed Podolian young bulls. Meat quality characteristics were measured on three different muscles [Longissimus dorsi (LD), Semimembranosus (SM) Semitendinosus (ST)], vacuum-packaged and chilled stored at 2-4°C for 15 days. The animals in the HC group had higher weight gain than those in the LC group (P<0.05). Slaughter data were not influenced by ration composition. The higher forage to concentrate ratio produced an improvement in fatty acid composition of the three muscles, with a higher polyunsaturated to saturated ratio (P<0.001). Vitamin E and malondialdehyde (MDA) contents were not affected by the feeding treatment. Panel scores for tenderness and flavour (P<0.01) and Warner-Bratzler Shear force (P<0.001) were significantly affected by muscle, the LD muscle being the most tender and the richest in flavour but they not affected by dietary treatment. PMID:22061725

Marino, R; Albenzio, M; Girolami, A; Muscio, A; Sevi, A; Braghieri, A

2005-09-29

383

Sensory, physical and chemical characteristics of cooked ham manufactured from rapidly chilled and earlier deboned M. semimembranosus.  

UK PubMed Central (United Kingdom)

Effects of rapid chilling of carcasses (at -31°C in the first 3h of chilling, and then at 2-4°C) and earlier deboning (8h post-mortem), compared to rapid (till 24h post-mortem) and conventional chilling (at 2-4°C, till 24h post-mortem), on quality characteristics of pork M. semimebranosus and cooked ham were investigated. Quality measurements included pH value, colour (CIEL a b values) and total aerobic count of M. semimebranosus, as well as sensory (colour, juiciness, texture, and flavour), physical (pH value, colour - CIEL a b values and texture - Warner-Bratzler shear and penetration forces) and chemical (protein, total fat, and moisture content) characteristics of cooked ham. The cooked ham was manufactured from pieces of M. semimebranosus with ultimate lightness (CIEL value) lower than 50. Rapid chilling and earlier deboning significantly increased quantity of M. semimebranosus desirable for cooked ham manufacturing. Earlier start of pork fabrication did not affect important quality characteristics of cooked ham.

Tomovi? VM; Jokanovi? MR; Petrovi? LS; Tomovi? MS; Tasi? TA; Ikoni? PM; Sumi? ZM; Soji? BV; Skaljac SB; Sošo MM

2013-01-01

384

Expression of genes related to quality of Longissimus dorsi muscle meat in Nellore (Bos indicus) and Canchim (5/8 Bos taurus × 3/8 Bos indicus) cattle.  

UK PubMed Central (United Kingdom)

This study was performed to compare CAPN1, CAPN2, CAST, TG, DGAT1 and LEP gene expressions and correlate them with meat quality traits in two genetic groups (Nellore and Canchim) in order to assess their expression profile and use their expression profile as genetic markers. We analyzed 30 young bulls (1year old), 15 of each genetic group. Samples of the Longissimus dorsi muscle were collected for analysis of: total lipids (TL) and meat tenderness measured as Warner-Bratzler shear force (SF) and myofibrillar fragmentation (MFI) at day of slaughter and 7days of aging. Gene expression profiles were obtained via RT-qPCR. TL and MFI showed differences between breeds, higher MFI in Canchim and higher TL in Nellore. Calpains showed no differential expression between groups, as did DGAT1, TG, and LEP. CAST was expressed more in the Nellore cattle. The only significant within-breed correlation (0.79) between gene expression and meat traits was found for DGAT1 and MFI in Canchim breed. Although the number of animals used in this study was small, the results indicate that the increased expression of CAST in Nellore may reflect tougher meat, but the lack of correlations with the meat traits indicates it is not a promising genetic marker.

Giusti J; Castan E; Dal Pai M; Arrigoni Mde B; Rodrigues Baldin S; De Oliveira HN

2013-06-01

385

Non-destructive assessment of instrumental and sensory tenderness of lamb meat using NIR hyperspectral imaging.  

Science.gov (United States)

The purpose of this study was to develop and test a hyperspectral imaging system (900-1700 nm) to predict instrumental and sensory tenderness of lamb meat. Warner-Bratzler shear force (WBSF) values and sensory scores by trained panellists were collected as the indicator of instrumental and sensory tenderness, respectively. Partial least squares regression models were developed for predicting instrumental and sensory tenderness with reasonable accuracy (Rcv=0.84 for WBSF and 0.69 for sensory tenderness). Overall, the results confirmed that the spectral data could become an interesting screening tool to quickly categorise lamb steaks in good (i.e. tender) and bad (i.e. tough) based on WBSF values and sensory scores with overall accuracy of about 94.51% and 91%, respectively. Successive projections algorithm (SPA) was used to select the most important wavelengths for WBSF prediction. Additionally, textural features from Gray Level Co-occurrence Matrix (GLCM) were extracted to determine the correlation between textural features and WBSF values. PMID:23768372

Kamruzzaman, Mohammed; Elmasry, Gamal; Sun, Da-Wen; Allen, Paul

2013-03-14

386

Feed efficiency and carcass and meat quality characteristics of bulls finished on diets containing varied proportions of wheat straw and wet sugar beet pulp  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Fifteen young Holstein Friesian bulls (18 mo of age) were divided into three groups of five. All groups were fed a diet consisting of 60% concentrate and 40% roughage. The control (C) group received a mixture of dry meadow hay, dry lucerne and wheat straw as roughage. The second and third treatment groups were fed a similar mixture of roughage partially substituting wheat straw with wet sugar beet pulp (SBP) at levels of 4% and 8% on a dry matter (DM) basis, respectively. (more) Dry matter intake and feed efficiency ratio (kg DM intake/kg weight gain) of the C group were significantly higher than those of the 4% SBP and 8% SBP groups. Slaughter and carcass traits indicated that there were no significant differences between dietary treatments. The inclusion of 8% SBP significantly improved panel ratings for tenderness, juiciness, beef flavour intensity and general acceptance, as well as number of chews before swallowing and the Warner Bratzler Shear value. Proximate analysis of the meat did not demonstrate differences between meat from the bulls fed C and the SBP diets. It was concluded that wheat straw could be replaced by 8% SBP in the finishing diet for young Holstein Friesian bulls in order to improve feed efficiency and sensory quality characteristics of their meat.

Yü ksel, S.; Yanar, M.; Turgut, L.; Ö zlü tü rk, A.; Kopuzlu, S.; Sezgin, E.

2009-01-01

387

Effects of DGAT1 gene on meat and carcass fatness quality in Chinese commercial cattle.  

UK PubMed Central (United Kingdom)

This study was designed to investigate the candidate single nucleotide polymorphisms (SNPs) in the exon's region of bovine diacylglycerol O-acyltransferase (DGAT1) gene using bioinformatics and experimental methods. A total of 17 SNPs were screened from public data resources and DNA sequencing. Three SNPs (c.572A>G, c.1241C>T and c.1416T>G) of these candidate SNPs were genotyped by created restriction site-polymerase chain reaction (CRS-PCR) methods. The gene-specific SNP markers and their effects on meat and carcass fatness quality traits were evaluated in Chinese commercial cattle. The c.572A>G and c.1416T>G significantly effected on backfat thickness, longissimus muscle area, marbling score, fat color and Warner-Bratzler shear force. No significant association was detected between the c.1241C>T and measured traits. Results from this study suggested that the SNP markers may be effective for the marker-assisted selection of meat and carcass fatness quality traits, and added new evidence that DGAT1 gene is an important candidate gene for the improvement of meat and carcass fatness quality in beef cattle industry.

Yuan Z; Li J; Li J; Gao X; Gao H; Xu S

2013-02-01

388

Effect of South African beef production systems on post-mortem muscle energy status and meat quality.  

UK PubMed Central (United Kingdom)

Post-slaughter muscle energy metabolism meat colour of South African production systems were compared; steers (n=182) of Nguni, Simmental Brahman crossbreds were reared on pasture until A-, AB-, or B-age, in feedlot until A-AB-age. After exsanguination carcasses were electrically stimulated (400 V for 15 s). M. longissimus dorsi muscle energy samples were taken at 1, 2, 4 and 20 h. Post-mortem samples for meat quality studies were taken at 1, 7 and 14 days post-mortem. Production systems affected muscle glycogen, glucose, glucose-6-P, lactic acid, ATP, creatine-P glycolytic potential (P<0.05), with the muscles of feedlot carcasses having a faster glycolysis rate than pasture carcasses. Energy metabolites correlated (0.40.5) water holding capacity, drip loss, and Warner Bratzler shear force. Muscle energy only affected muscle contraction of the A-age-pasture system (shortest sarcomere length of 1.66 ?m vs 1.75 ?m highest WBS of 6 kg vs 5 kg 7 days post-mortem).

Frylinck L; Strydom PE; Webb EC; du Toit E

2013-04-01

389

Eating quality of "Vitela Tradicional do Montado"-PGI veal and Mertolenga-PDO veal and beef.  

UK PubMed Central (United Kingdom)

Physicochemical and sensory characteristics were measured in veal and beef from the Portuguese Mertolenga breed having 3 quality labels as follows: Mertolenga-PDO beef and veal which apply to purebred animals and "Vitela Tradicional do Montado"-PGI veal which applies to crossbred animals. Measurements were made in longissimus lumborum muscle aged for 6days. The temperature 3h post-mortem (T3), cooking losses and Warner-Bratzler shear force (WBSF) reflected carcass weight (CW) differences between groups. The pigment content was influenced by age, with beef having higher values than veal. WBSF correlated negatively with intramuscular fat in Mertolenga-PDO beef, but not on veal. WBSF correlated positively with cooking losses and negatively with myofibrillar fragmentation index, tenderness, juiciness and overall acceptability. Cooking losses and juiciness were the main contributors for the tenderness differences. Vitela Tradicional do Montado-PGI and Mertolenga-PDO veal had lighter colour and were considered tender. The three meat types were well discriminated based on pHu, a* and C* parameters by canonical discriminant analysis.

Monteiro AC; Gomes E; Barreto AS; Silva MF; Fontes MA; Bessa RJ; Lemos JP

2013-05-01

390

Microstructure alterations in beef intramuscular connective tissue caused by hydrodynamic pressure processing.  

Science.gov (United States)

Scanning electron microscopy (SEM) was utilized to evaluate microstructural changes in intramuscular connective tissue of beef semimembranosus muscle subjected to hydrodynamic pressure processing (HDP). Samples were HDP treated in a plastic container (HDP-PC) or a steel commercial unit (HDP-CU). Control and HDP samples were obtained immediately post-treatment and after 14days of aging for SEM and Warner-Bratzler shear force (WBSF) analysis. Immediately post-treatment, HDP treated samples exhibited lower (P<0.01) WBSF than did controls. After aging, HDP-PC samples had lower (P<0.01) WBSF than that of aged controls. SEM analysis indicated that HDP-PC treatment disrupted the integrity of the collagen fibril network of the endomysium in both the non-aged and aged samples. Aging effects on the intramuscular connective tissue were observed in the HDP-PC and control samples. Both WBSF and connective tissue changes were greater in the HDP-PC than in the HDP-CU treated samples. Data suggest that shockwave alterations to connective tissue contribute to the meat tenderization of HDP. PMID:23803280

Zuckerman, H; Bowker, B C; Eastridge, J S; Solomon, M B

2013-06-05

391

Fast determination of beef quality parameters with time-domain nuclear magnetic resonance spectroscopy and chemometrics.  

Science.gov (United States)

The noteworthy of this study is to predict seven quality parameters for beef samples using time-domain nuclear magnetic resonance (TD-NMR) relaxometry data and multivariate models. Samples from 61 Bonsmara heifers were separated into five groups based on genetic (breeding composition) and feed system (grain and grass feed). Seven sample parameters were analyzed by reference methods; among them, three sensorial parameters, flavor, juiciness and tenderness and four physicochemical parameters, cooking loss, fat and moisture content and instrumental tenderness using Warner Bratzler shear force (WBSF). The raw beef samples of the same animals were analyzed by TD-NMR relaxometry using Carr-Purcell-Meiboom-Gill (CPMG) and Continuous Wave-Free Precession (CWFP) sequences. Regression models computed by partial least squares (PLS) chemometric technique using CPMG and CWFP data and the results of the classical analysis were constructed. The results allowed for the prediction of aforementioned seven properties. The predictive ability of the method was evaluated using the root mean square error (RMSE) for the calibration (RMSEC) and validation (RMSEP) data sets. The reference and predicted values showed no significant differences at a 95% confidence level. PMID:23601874

Pereira, Fabíola Manhas Verbi; Bertelli Pflanzer, Sérgio; Gomig, Thaísa; Lugnani Gomes, Carolina; de Felício, Pedro Eduardo; Colnago, Luiz Alberto

2013-03-07

392

Fast determination of beef quality parameters with time-domain nuclear magnetic resonance spectroscopy and chemometrics.  

UK PubMed Central (United Kingdom)

The noteworthy of this study is to predict seven quality parameters for beef samples using time-domain nuclear magnetic resonance (TD-NMR) relaxometry data and multivariate models. Samples from 61 Bonsmara heifers were separated into five groups based on genetic (breeding composition) and feed system (grain and grass feed). Seven sample parameters were analyzed by reference methods; among them, three sensorial parameters, flavor, juiciness and tenderness and four physicochemical parameters, cooking loss, fat and moisture content and instrumental tenderness using Warner Bratzler shear force (WBSF). The raw beef samples of the same animals were analyzed by TD-NMR relaxometry using Carr-Purcell-Meiboom-Gill (CPMG) and Continuous Wave-Free Precession (CWFP) sequences. Regression models computed by partial least squares (PLS) chemometric technique using CPMG and CWFP data and the results of the classical analysis were constructed. The results allowed for the prediction of aforementioned seven properties. The predictive ability of the method was evaluated using the root mean square error (RMSE) for the calibration (RMSEC) and validation (RMSEP) data sets. The reference and predicted values showed no significant differences at a 95% confidence level.

Pereira FM; Bertelli Pflanzer S; Gomig T; Lugnani Gomes C; de Felício PE; Colnago LA

2013-04-01

393

Effect of suspension method and aging time on meat quality of Chinese fattened cattle M. Longissimus dorsi.  

UK PubMed Central (United Kingdom)

Objectives of the present study were to evaluate the effects of suspension method and aging time on quality traits of Chinese fattened cattle M. Longissimus dorsi (LD). At the end of the slaughter line, the right sides of carcasses were re-hung from the pelvic bone obturator foramen, while the left sides remained hung by Achilles tendon suspension (AS). LD muscles were aged for 1, 7, 14 and 21days and were then evaluated for quality index. Pelvic suspension (PS) significantly decreased the WBSF of beef muscle at 1d and 7d postmortem compared with AS. The tenderness with PS at 7d postmortem was similar with that of AS at 14d. Moreover, PS increased sarcomere length and decreased purge loss of LD significantly. In addition, aging time had a significant effect on pH, meat color, Warner-Bratzler shear force, and myofibril fragmentation index of LD muscle. To conclude, PS is valuable to be introduced to the beef industry in China for rapid (within 7days) improvement of beef tenderness and decreased aging time of Chinese fattened cattle.

Hou X; Liang R; Mao Y; Zhang Y; Niu L; Wang R; Liu C; Liu Y; Luo X

2014-01-01

394

Effect of bleeding method and low voltage electrical stimulation on meat quality of ostriches  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The effect on ostrich muscle quality of an additional thoracic stick (TS) to the normal ventral throat slit to bleed ostriches after electrical stunning was evaluated. The additional TS had no negative or positive effect on the drip loss, cooking loss, colour or pH and temperature readings of the fillet (Muscularis iliofibularis), big drum (M. gastrocnemius, pars interna) and inside loin (M. iliotibialis cranialis). None the less, personal observations would recommend the (more) use of TS due to ethical considerations. An early post mortem low voltage electrical stimulation (ES) of the carcasses also had no influence on the cooking loss, drip loss and colour of these muscles. Electrical stimulation did result in a lower pH45 in both the fillet and big drum muscles. However, after 24 h the pH of the muscles did not differ. Electrical stimulation also caused elevated initial muscle temperatures, although this effect was only temporary due to the efficient cooling mechanism used in the abattoir. Electrical stimulation also had no effect on the Warner Bratzler shear force values in the fillet. It can be concluded that low voltage ES has no advantage pertaining to physical quality characteristics of importance in an ostrich abattoir.

Hoffman, L.C.; Cloete, S.W.P.; van Schalkwyk, S.J.; Botha, S.St.C.

2009-01-01

395

Effects of early maternal separation of lambs and rearing with minimal and maximal human contact on meat quality.  

Science.gov (United States)

The present study aims to assess the effect of gentling on behaviour and meat quality of lambs. Thirty-two Comisana lambs were divided into four groups of eight animals: ER (ewe reared), AR (artificially reared) and the corresponding gentled groups ERG and ARG. The provision of human contacts stimulated gentled subjects to explore, whereas the proportion of idling subjects was reduced (P<0.10). At increasing age the number of subjects contacting the person increased in the gentled groups (P<0.05). Lambs left with their dams showed higher warm and cold carcass yields compared to artificially reared animals, although animals benefiting from both maternal care and gentling, had the highest dressing percentage (P<0.05). Values of pH declined more rapidly in meat from gentled animals than from ungentled subjects (P<0.05), b* and h values were higher in ARG than in AR group (P<0.05), whereas Warner-Bratzler shear force and hardness tended to be lower in gentled lambs (P<0.15). We conclude that human-animal relationship can play an important role in affecting welfare, productive performances and meat quality of lambs, in particular when young subjects are prematurely separated from mothers. PMID:22061873

Napolitano, F; Caroprese, M; Girolami, A; Marino, R; Muscio, A; Sevi, A

2005-11-10

396

Effects of early maternal separation of lambs and rearing with minimal and maximal human contact on meat quality.  

UK PubMed Central (United Kingdom)

The present study aims to assess the effect of gentling on behaviour and meat quality of lambs. Thirty-two Comisana lambs were divided into four groups of eight animals: ER (ewe reared), AR (artificially reared) and the corresponding gentled groups ERG and ARG. The provision of human contacts stimulated gentled subjects to explore, whereas the proportion of idling subjects was reduced (P<0.10). At increasing age the number of subjects contacting the person increased in the gentled groups (P<0.05). Lambs left with their dams showed higher warm and cold carcass yields compared to artificially reared animals, although animals benefiting from both maternal care and gentling, had the highest dressing percentage (P<0.05). Values of pH declined more rapidly in meat from gentled animals than from ungentled subjects (P<0.05), b* and h values were higher in ARG than in AR group (P<0.05), whereas Warner-Bratzler shear force and hardness tended to be lower in gentled lambs (P<0.15). We conclude that human-animal relationship can play an important role in affecting welfare, productive performances and meat quality of lambs, in particular when young subjects are prematurely separated from mothers.

Napolitano F; Caroprese M; Girolami A; Marino R; Muscio A; Sevi A

2006-04-01

397

Relationship between commercially available DNA analysis and phenotypic observations on beef quality and tenderness.  

UK PubMed Central (United Kingdom)

Warner-Bratzler shear force values from 560 mixed breed heifers and steers were used to determine estimates of genetic selection. Cattle were marketed from 2008 to 2011, and included five feedlot based research projects at the North Dakota State University-Carrington Research Extension Center. Samples were collected for IGENITY® analysis providing information that included selection indices and estimated breeding values for carcass traits. DNA-based test results were compared with actual carcass measurements. Marbling accounted for over 10% of the variation in WBSF while hot carcass weight was the second most influential carcass trait accounting for 4% (P<0.01). Regression coefficients of IGENITY® molecular breeding value on phenotype for WBSF, marbling, ribeye area, yield grade, and fat thickness were low (R(2)=0.14, 0.02, 0.03, 0.03, and 0.02, respectively). Therefore selecting cattle for a higher degree of marbling and feeding a diet that meets or exceeds recommended nutrients for growth are the most important factors influencing beef tenderness and acceptability.

Magolski JD; Buchanan DS; Maddock-Carlin KR; Anderson VL; Newman DJ; Berg EP

2013-11-01

398

Effect of suspension method and aging time on meat quality of Chinese fattened cattle M. Longissimus dorsi.  

Science.gov (United States)

Objectives of the present study were to evaluate the effects of suspension method and aging time on quality traits of Chinese fattened cattle M. Longissimus dorsi (LD). At the end of the slaughter line, the right sides of carcasses were re-hung from the pelvic bone obturator foramen, while the left sides remained hung by Achilles tendon suspension (AS). LD muscles were aged for 1, 7, 14 and 21days and were then evaluated for quality index. Pelvic suspension (PS) significantly decreased the WBSF of beef muscle at 1d and 7d postmortem compared with AS. The tenderness with PS at 7d postmortem was similar with that of AS at 14d. Moreover, PS increased sarcomere length and decreased purge loss of LD significantly. In addition, aging time had a significant effect on pH, meat color, Warner-Bratzler shear force, and myofibril fragmentation index of LD muscle. To conclude, PS is valuable to be introduced to the beef industry in China for rapid (within 7days) improvement of beef tenderness and decreased aging time of Chinese fattened cattle. PMID:24056407

Hou, Xu; Liang, Rongrong; Mao, Yanwei; Zhang, Yimin; Niu, Lebao; Wang, Renhuan; Liu, Chenglong; Liu, Yuqing; Luo, Xin

2013-08-27

399

Eating quality of "Vitela Tradicional do Montado"-PGI veal and Mertolenga-PDO veal and beef.  

Science.gov (United States)

Physicochemical and sensory characteristics were measured in veal and beef from the Portuguese Mertolenga breed having 3 quality labels as follows: Mertolenga-PDO beef and veal which apply to purebred animals and "Vitela Tradicional do Montado"-PGI veal which applies to crossbred animals. Measurements were made in longissimus lumborum muscle aged for 6days. The temperature 3h post-mortem (T3), cooking losses and Warner-Bratzler shear force (WBSF) reflected carcass weight (CW) differences between groups. The pigment content was influenced by age, with beef having higher values than veal. WBSF correlated negatively with intramuscular fat in Mertolenga-PDO beef, but not on veal. WBSF correlated positively with cooking losses and negatively with myofibrillar fragmentation index, tenderness, juiciness and overall acceptability. Cooking losses and juiciness were the main contributors for the tenderness differences. Vitela Tradicional do Montado-PGI and Mertolenga-PDO veal had lighter colour and were considered tender. The three meat types were well discriminated based on pHu, a* and C* parameters by canonical discriminant analysis. PMID:23391863

Monteiro, Ana C G; Gomes, Eduardo; Barreto, António S; Silva, Marina F; Fontes, Magda A; Bessa, Rui J B; Lemos, José P C

2013-01-04

400

Tenderness profiles of ten muscles from F1 Bos indicus x Bos taurus and Bos taurus cattle cooked as steaks and roasts.  

Science.gov (United States)

Twenty Bos taurus (Hereford x Angus crosses) and 20 F1 Bos indicus x Bos taurus heifers of the same age, management and feeding regimen, were harvested and evaluated at 2 days postmortem for carcass and meat traits. Ten muscles were obtained from the right sides and aged until 10 days postmortem. Bos indicus carcasses were lighter, had less fat cover, smaller ribeyes, and less intramuscular lipid (all p?0.05). Bos taurus longissimus lumborum, gluteus medius, triceps brachii, and semimembranosus muscles cooked as steaks and roasts had a lower Warner-Bratzler shear force (WBSF) (p?0.05) than those from Bos indicus. Bos taurus deep pectoral and semitendinosus muscles cooked as roasts had a lower WBSF (p<0.05) than Bos indicus. Infraspinatus, longissimus lumborum, and semitendinosus muscles were more tender (p<0.05) as roasts than steaks, whereas the opposite was true for the deep pectoral and semimembranosus muscles. Seven of the 10 muscles had lower WBSF (p?0.05) for Bos taurus when cooked as steaks, roasts or both. PMID:22166845

Highfill, C M; Esquivel-Font, O; Dikeman, M E; Kropf, D H

2011-11-12

 
 
 
 
401

Tenderness profiles of ten muscles from F1 Bos indicus x Bos taurus and Bos taurus cattle cooked as steaks and roasts.  

UK PubMed Central (United Kingdom)

Twenty Bos taurus (Hereford x Angus crosses) and 20 F1 Bos indicus x Bos taurus heifers of the same age, management and feeding regimen, were harvested and evaluated at 2 days postmortem for carcass and meat traits. Ten muscles were obtained from the right sides and aged until 10 days postmortem. Bos indicus carcasses were lighter, had less fat cover, smaller ribeyes, and less intramuscular lipid (all p?0.05). Bos taurus longissimus lumborum, gluteus medius, triceps brachii, and semimembranosus muscles cooked as steaks and roasts had a lower Warner-Bratzler shear force (WBSF) (p?0.05) than those from Bos indicus. Bos taurus deep pectoral and semitendinosus muscles cooked as roasts had a lower WBSF (p<0.05) than Bos indicus. Infraspinatus, longissimus lumborum, and semitendinosus muscles were more tender (p<0.05) as roasts than steaks, whereas the opposite was true for the deep pectoral and semimembranosus muscles. Seven of the 10 muscles had lower WBSF (p?0.05) for Bos taurus when cooked as steaks, roasts or both.

Highfill CM; Esquivel-Font O; Dikeman ME; Kropf DH

2012-04-01

402

Tenderness profiles of ten muscles from F1 Bos indicus x Bos taurus and Bos taurus cattle cooked as steaks and roasts  

UK PubMed Central (United Kingdom)

Twenty Bos taurus (Hereford x Angus crosses) and 20 F1 Bos indicus x Bos taurus heifers of the same age, management and feeding regimen, were harvested and evaluated at 2days postmortem for carcass and meat traits. Ten muscles were obtained from the right sides and aged until 10days postmortem. Bos indicus carcasses were lighter, had less fat cover, smaller ribeyes, and less intramuscular lipid (all p?0.05). Bos taurus longissimus lumborum, gluteus medius, triceps brachii, and semimembranosus muscles cooked as steaks and roasts had a lower Warner–Bratzler shear force (WBSF) (p?0.05) than those from Bos indicus. Bos taurus deep pectoral and semitendinosus muscles cooked as roasts had a lower WBSF (p<0.05) than Bos indicus. Infraspinatus, longissimus lumborum, and semitendinosus muscles were more tender (p<0.05) as roasts than steaks, whereas the opposite was true for the deep pectoral and semimembranosus muscles. Seven of the 10 muscles had lower WBSF (p?0.05) for Bos taurus when cooked as steaks, roasts or both.

Highfill CM; Esquivel-Font O; Dikeman ME; Kropf DH

2012-04-01

403

Comparison of proximate chemical composition and texture of cupim, Rhomboideus m. and lombo, Longissimus dorsi m. of Nelore (Bos indicus)  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A composição química percentual aproximada do cupim m. Rhomboideus (RB) derivado de Nelore (Bos indicus) de 24 meses de idade mostrou ser um músculo diferenciado. Há uma maior fração de material lipídico em RB chegando a ser 14 vezes proporcionalmente maior em comparação ao m. Longissimus dorsi (LD) (p(more) oporcionalmente maior concentração da fração protéica e menor quantidade de umidade em RB. O teor de colágeno foi de 22,9% mais concentrado em RB enquanto que a quantidade da sua ligação cruzada, hidroxilisilpiridinolina (HP) foi 14 vezes maior indicando que cupim seria mais rígido. Contrariando essa expectativa, a maciez da carne crua avaliada pelo texturômetro mostrou valores de 8.05 e 5.81 kg/F para LD e RB, respectivamente (p Abstract in english The proximate chemical composition of hump, known in Brazil as cupim, Rhomboideus m. (RB), of Nelore (Bos indicus) aged 24 months revealed it to be a unique beef muscle. It presents a lipid fraction 14-fold as high as that of Longissimus dorsi m. (LD) taken from the same animal (p(more) RB. Analysis of collagen and its crosslinking with hydroxylysylpyridinium (HP) showed there to be 22.9% more collagen and 14-fold as much HP in RB as in LD. Contrary to the expectations, the tenderness of fresh samples evaluated by Warner Bratzler shear force measurements led to values of 8.05 and 5.81 kgf for LD and RB, respectively (p

Pedrão, Mayka Reghiany; Lassance, Fernanda; Souza, Nilson Evelazio de; Matsushita, Makoto; Telles, Paulo; Shimokomaki, Massami

2009-06-01

404

Prediction of beef quality attributes using VIS/NIR hyperspectral scattering imaging technique  

UK PubMed Central (United Kingdom)

Hyperspectral imaging images were used to predict fresh beef tenderness (WBSF: Warner–Bratzler Shear Force) and color parameters (L?,a?,b?). Sixty-five fresh strip loin cuts were collected from 33 carcass after 2days postmortem. After acquiring hyperspectral images, the samples were vacuum packaged and aged for 7days, and then the color parameters and WBSF of the samples were measured as references. The optical scattering profiles were extracted from the images and fitted to the Lorentzian distribution (LD) function with three parameters. LD parameters, such as the scattering asymptotic vale, the peak height, and full scattering width were determined at each wavelength. Stepwise discrimination was used to identify optimal wavelengths. The LD parameters’ combinations with optimal wavelengths were used to establish multi-linear regression (MLR) models to predict the beef attributes. The models were able to predict beef WBSF with Rc?=0.91, and color parameters (L?,a?,b?) with Rc? of 0.96, 0.96 and 0.97, respectively.

Wu J; Peng Y; Li Y; Wang W; Chen J; Dhakal S

2012-03-01

405

Interface shear and pressure characteristics of wheelchair seat cushions  

Directory of Open Access Journals (Sweden)

Full Text Available Pressure ulcer incidence rates have remained constant despite advances in support surface technology. Interface shear stress is recognized as a risk factor for pressure ulcer development and is the focus of many shear reduction technologies incorporated into wheelchair cushions; however, shear reduction has not been quantified in the literature. We evaluated 21 commercial wheelchair seat cushions using a new methodology developed to quantify interface shear stress, interface pressure, and horizontal stiffness. Interface shear stress increased significantly with applied horizontal indenter displacement, while no significant difference was found for interface pressure. Material of construction resulted in significant differences in interface shear stress, interface pressure, and horizontal stiffness. This study shows that the existing International Organization for Standardization (ISO) 16840-2 horizontal stiffness measure provides similar information to the new horizontal stiffness measure. The lack of a relationship between interface shear stress and the overall horizontal stiffness measure, however, suggests that a pressure and shear force sensor should be used with the ISO 16840-2 horizontal stiffness measure to fully quantify a cushion's ability to reduce interface shear stress at the patient's bony prominences.

Jonathan S. Akins; Patricia E. Karg, MS; David M. Brienza, PhD

2011-01-01

406

Development of shear capacity equations for rectangular reinforced concrete beams  

International Nuclear Information System (INIS)

The problem of shear is not yet fully understood due to involvement of number of parameters. Designers are extra careful about shear, especially in beams and consequently higher safety factors are used in shear design. Several equations are available in literature to determine the shear capacity of beams, i.e. ACI equation, Zsutty equation and KIM and White equation. To verify the application of these equations, extensive experimental study was carried out on rectangular reinforced concrete beams without web reinforcement. Three parameters i.e. compressive strength, percentage of tension steel and shear span to depth ratio were considered and equations were developed for the shear strength prediction. Results of the study show that the concrete shear capacity ranges from 1.7' 1fc' to 1.B 'If c' before any cracking is observed. After cracking, concrete shear capacity is almost exhausted and most of the applied shear is taken by steel till failure. It is also revealed that ACI equation is most conservative for all values of aid, ft and p. (author)

2010-01-01

407

Onset of three-dimensional shear in granular flow.  

Energy Technology Data Exchange (ETDEWEB)

The evolution of granular shear flow is investigated as a function of height in a split-bottom Couette cell. Using particle tracking, magnetic-resonance imaging, and large-scale simulations, we find a transition in the nature of the shear as a characteristic height H* is exceeded. Below H* there is a central stationary core; above H* we observe the onset of additional axial shear associated with torsional failure. Radial and axial shear profiles are qualitatively different: the radial extent is wide and increases with height, while the axial width remains narrow and fixed.

Lechman, Jeremy B.; Nagel, Sidney, R. (University of Chicago, Chicago, IL); Grest, Gary Stephen; Mobius, Matthias E. (University of Chicago, Chicago, IL); Karczmar, Greg S. (University of Chicago, Chicago, IL); Heinrich, M. Jaeger (University of Chicago, Chicago, IL); Barbero, Antonio F. (University of Chicago, Chicago, IL); Cheng, Xiang (University of Chicago, Chicago, IL)

2005-07-01

408

Onset of three-dimensional shear in granular flow  

CERN Document Server

The onset and evolution of granular shear flow is investigated as a function of height in a split-bottom Couette cell. Using particle tracking, magnetic-resonance imaging, and large-scale simulations we find a transition in the nature of the shear as a characteristic height $H^*$ is exceeded. Below $H^*$ there is a central stationary core; above $H^*$ we observe the onset of additional axial shear associated with torsional failure. Radial and axial shear profiles are qualitatively different: the radial extent is wide and increases with height while the axial width remains narrow and fixed.

Cheng, X; Barbero, A F; Grest, G S; Jäger, H M; Karczmar, G S; Möbius, M E; Nagel, S R; Cheng, Xiang; Lechman, Jeremy B.; Barbero, Antonio F.; Grest, Gary S.; Jaeger, Heinrich M.; Karczmar, Greg S.; M\\"{o}bius, Matthias E.; Nagel, Sidney R.

2005-01-01

409

Punching and radial shear problems in reinforced concrete containments  

International Nuclear Information System (INIS)

Current design approaches for punching (peripheral) shear are discussed in light of recent experimental results which show little decrease in punching strength with increasing biaxial tension up to about 0.9f/sub y/. It appears that considerable increase in design capacity is warranted, leading to much less congestion of steel. The problem of radial shear in pressurized containments is discussed, especially the complex state of stresses deformations, and cracking near the base. Research required to finalize improved design and licensing methods for punching shear and radial shear is described, together with potential benefits in terms of material savings, safety, qualification of existing facilities for higher loads, and quality control.

1982-01-01

410

Non-universal shear viscosity from Einstein gravity  

International Nuclear Information System (INIS)

A very famous result of gauge/gravity duality is the universality of the ratio of shear viscosity to entropy density in every field theory holographically dual to classical, two-derivative (Einstein) gravity. We present a way to obtain deviation from this universality by breaking the rotational symmetry spontaneously. In anisotropic fluids additional shear modes exist and their corresponding shear viscosities may be non-universal. We confirm this by explicitly calculating the shear viscosities in a transversely isotropic background, a p-wave superfluid, and study its critical behavior. This is a first decisive step towards further applications of gauge/gravity duality to physical systems.

2011-05-16

411

Non-universal shear viscosity from Einstein gravity  

CERN Multimedia

A very famous result of gauge/gravity duality is the universality of the ratio of shear viscosity to entropy density in every field theory holographically dual to classical, two-derivative (Einstein) gravity. We present a way to obtain deviation form this universality by breaking the rotational symmetry spontaneously. In anisotropic fluids additional shear modes exist and their corresponding shear viscosities may be non-universal. We confirm this by explicitly calculating the shear viscosities in a transversely isotropic background, a p-wave superfluid, and study its critical behavior. This is a first decisive step towards further applications of gauge/gravity duality to physical systems.

Erdmenger, Johanna; Zeller, Hansjörg

2010-01-01

412

Aerosol penetration through a seismically loaded shear wall  

International Nuclear Information System (INIS)

[en] An experimental study was performed to measure the aerosol penetration through a reinforced concrete shear wall after simulated seismic damage. Static load-cycle testing, to stress levels sufficient to induce visible shear cracking, was used to simulate the earthquake loading. Air permeability tests were performed both before and after the simulated seismic loading damaged the structure. Aerosol penetration measurements were conducted on the cracked shear wall structure using 0.10 ?m monodisperse particles. The measured aerosol number penetration through the cracked shear wall was 0.5%. 7 refs

1992-01-01

413

Aerosol penetration through a seismically loaded shear wall  

Energy Technology Data Exchange (ETDEWEB)

An experimental study was performed to measure the aerosol penetration through a reinforced concrete shear wall after simulated seismic damage. Static load-cycle testing, to stress levels sufficient to induce visible shear cracking, was used to simulate the earthquake loading. Air permeability tests were performed both before and after the simulated seismic loading damaged the structure. Aerosol penetration measurements were conducted on the cracked shear wall structure using 0.10 {mu}m monodisperse particles. The measured aerosol number penetration through the cracked shear wall was 0.5%. 7 refs.

Farrar, C.R.; Girrens, S.P.

1992-01-01

414

Aerosol penetration through a seismically loaded shear wall  

Energy Technology Data Exchange (ETDEWEB)

An experimental study was performed to measure the aerosol penetration through a reinforced concrete shear wall after simulated seismic damage. Static load-cycle testing, to stress levels sufficient to induce visible shear cracking, was used to simulate the earthquake loading. Air permeability tests were performed both before and after the simulated seismic loading damaged the structure. Aerosol penetration measurements were conducted on the cracked shear wall structure using 0.10 {mu}m monodisperse particles. The measured aerosol number penetration through the cracked shear wall was 0.5%. 7 refs.

Farrar, C.R.; Girrens, S.P.

1992-05-01

415

Shear-induced metastable states of end-grafted polystyrene  

International Nuclear Information System (INIS)

[en] The in situ molecular scale response of end-grafted polystyrene to shear against a deuterated polystyrene melt was investigated with neutron reflectometry. The derived grafted polystyrene density profiles showed that the grafted polystyrene was retained on the quartz wafer during the measurements. The profiles suggested that the end-grafted polystyrene response to shear results in a series of metastable states, rather than equilibrium states assumed in the current theory. Except for some possible extension and/or contraction of the grafted polystyrene with shear, there was no obvious correlation between the grafted polymer structure and the shear thinning behavior observed in these samples.

2011-01-01

416

Structural changes and orientaional order in a sheared colloidal suspension  

Energy Technology Data Exchange (ETDEWEB)

Small angle neutron scattering experiments were carried out on a charged stabilized dense colloidal suspension to observe changes in lattice structure as a function of shear rate. It is shown that (1) the lattice will evolve from a crystalline state in equilibrium to a polycrystalline state if subjected to a very low shear; and (2) as the shear is increased, partial order is reestablished with the apparent appearance of sliding layer flow. The transitions are reversible. The first transition occurs when the dynamic yield stress is exceeded; the second is discontinuous and is associated with an anomalous flow region in which the stress decreases with increasing shear rate.

Chen, L.B.; Zukoski, C.F. (Department of Chemical Engineering, University of Illinois, Urbana, Illinois 61801 (United States)); Ackerson, B.J. (Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078 (United States)); Hanley, H.J.M.; Straty, G.C. (Thermophysics Division, National Institute of Standards and Technology, Boulder, Colorado 80303 (United States)); Barker, J.; Glinka, C.J. (Reactor Radiation Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States))

1992-07-27

417

Yielding and flow of sheared colloidal glasses  

International Nuclear Information System (INIS)

We have studied some of the rheological properties of suspensions of hard-sphere colloids with particular reference to behaviour near the concentration of the glass transition. First we monitored the strain on the samples during and after a transient step stress. We find that, at all values of applied step stress, colloidal glasses show a rapid, apparently elastic, recovery of strain after the stress is removed. This recovery is found even in samples which have flowed significantly during stressing. We attribute this behaviour to 'cage elasticity', the recovery of the stress-induced distorted environment of any particle to a more isotropic state when the stress is removed. Second, we monitored the stress as the strain rate dot ? of flowing samples was slowly decreased. Suspensions which are glassy at rest show a stress which becomes independent of dot ? as dot ? ?0. This limiting stress can be interpreted as the yield stress of the glass and agrees well both with the yield stress deduced from the step stress and recovery measurements and that predicted by a recent mode coupling theory of sheared suspensions. Thus, the behaviours under steady shearing and transient step stress both support the idea that colloidal glasses have a finite yield stress. We note however that the samples do exhibit a slow accumulation of strain due to creep at stresses below the yield stress.

2004-09-29

418

Symplectic integrators in the shearing sheet  

CERN Document Server

The shearing sheet is a model dynamical system that is used to study the small-scale dynamics of astrophysical disks. Numerical simulations of particle trajectories in the shearing sheet usually employ the leapfrog integrator, but this integrator performs poorly because of velocity-dependent (Coriolis) forces. We describe two new integrators for this purpose; both are symplectic, time-reversible and second-order accurate, and can easily be generalized to higher orders. Moreover, both integrators are exact when there are no small-scale forces such as mutual gravitational forces between disk particles. In numerical experiments these integrators have errors that are often several orders of magnitude smaller than competing methods. The first of our new integrators (SEI) is well-suited for disks in which the typical inter-particle separation is large compared to the particles' Hill radii (e.g., planetary rings), and the second (SEKI) is designed for disks in which the particles are on bound orbits or the separatio...

Rein, Hanno

2011-01-01

419

Amorphous Systems in Athermal, Quasistatic Shear  

CERN Multimedia

We present results on a series of 2D atomistic computer simulations of amorphous systems subjected to simple shear in the athermal, quasistatic limit. The athermal quasistatic trajectories are shown to separate into smooth, reversible elastic branches which are intermittently broken by discrete catastrophic plastic events. The onset of a typical plastic event is studied with precision, and it is shown that the mode of the system which is responsible for the loss of stability has structure in real space which is consistent with a quadrupolar source acting on an elastic matrix. The plastic events themselves are shown to be composed of localized shear transformations which organize into lines of slip which span the length of the simulation cell, and a mechanism for the organization is discussed. Although within a single event there are strong spatial correlations in the deformation, we find little correlation from one event to the next, and these transient lines of slip are not to be confounded with the persiste...

Maloney, C E; Maloney, Craig E.; Lema\\^{\\i}tre, Ana\\"el

2005-01-01

420

Reynolds stress and shear flow generation  

International Nuclear Information System (INIS)

The so-called Reynolds stress may give a measure of the self-consistent flow generation in turbulent fluids and plasmas by the small-scale turbulent fluctuations. A measurement of the Reynolds stress can thus help to predict flows, e.g. shear flows in plasmas. This may assist the understanding of improved confinement scenarios such as H-mode confinement regimes. However, the determination of the Reynolds stress requires measurements of the plasma potential, a task that is difficult in general and nearly impossible in hot plasmas in large devices. In this work we investigate an alternative method, based on density measurements, to estimate the Reynolds stress, and demonstrate the validity range of this quantity, which we term the pseudo-Reynolds stress. The advantage of such a quantity is that accurate measurements of density fluctuations are much easier to obtain experimentally. Prior to the treatment of the pseudo-Reynolds stress, we present analytical and numerical results which demonstrate that the Reynolds stress in a plasma, indeed, generates a poloidal shear flow. The numerical simulations are performed both in a drift wave turbulence regime and a resistive interchange turbulence regime. Finally, the implications of misaligned probe arrays on the determination of Reynolds stresses are investigated, and alignment is found to be important but not severe. (author)

2001-01-01

 
 
 
 
421

Sheares' method of vaginoplasty - our experience.  

UK PubMed Central (United Kingdom)

INTRODUCTION: The Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome is one of the most common causes of primary amenorrhoea and is associated with vaginal atresia and absent uterus despite the presence of normal ovaries and external genitalia. Various techniques have been used, with many disadvantages, to create a neovagina. AIMS AND OBJECTIVES: Our aim is to create a neovagina with a simple and safe method. MATERIALS AND METHODS: We have operated 18 cases of MRKH syndrome with the Sheares' method of vaginoplasty, in which the space between the two labia is dilated with a Hegar's dilator along the vestigial Mullerian ducts. Thus, two tunnels are created and the central septum is excised to form a single vagina. A mould covered with amnion is placed in the neovagina. All cases are followed up for six months. They have all had a good length of vagina with regular manual dilatation. CONCLUSIONS: The Sheares' method of vaginoplasty is an easy and safe method to create a neovagina with least complications, like injury to urinary bladder, rectum or bleeding.

Chakrabarty S; Mukhopadhyay P; Mukherjee G

2011-05-01

422