Relevant bibliographies by topics / Strain-specific differences

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  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters
  4. Conference papers

Academic literature on the topic 'Strain-specific differences'

Author: Grafiati
Published: 4 June 2021
Last updated: 5 February 2022

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Journal articles on the topic "Strain-specific differences"

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Ayers, Jacob I., Anthony E. Kincaid, and Jason C. Bartz. "Prion Strain Targeting Independent of Strain-Specific Neuronal Tropism." Journal of Virology 83, no. 1 (October 29, 2008): 81–87. http://dx.doi.org/10.1128/jvi.01745-08.

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ABSTRACT While neuropathological features that define prion strains include spongiform degeneration and deposition patterns of PrPSc, the underlying mechanism for the strain-specific differences in PrPSc targeting is not known. To investigate prion strain targeting, we inoculated hamsters in the sciatic nerve with either the hyper (HY) or drowsy (DY) strain of the transmissible mink encephalopathy (TME) agent. Both TME strains were initially retrogradely transported in the central nervous system (CNS) exclusively by four descending motor tracts. The locations of HY and DY PrPSc deposition were identical throughout the majority of the incubation period. However, differences in PrPSc deposition between these strains were observed upon development of clinical disease. The differences observed were unlikely to be due to strain-specific neuronal tropism, since comparison of PrPSc deposition patterns by different routes of infection indicated that all brain areas were susceptible to prion infection by both TME strains. These findings suggest that prion transport and differential susceptibility to prion infection are not solely responsible for prion strain targeting. The data suggest that differences in PrPSc distribution between strains during clinical disease are due to differences in the length of time that PrPSc has to spread in the CNS before the host succumbs to disease.
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SCHULZ, H., C. JOHNER, G. EDER, A. ZIESENIS, P. REITMEIER, J. HEYDER, and R. BALLING. "Respiratory mechanics in mice: strain and sex specific differences." Acta Physiologica Scandinavica 174, no. 4 (April 2002): 367–75. http://dx.doi.org/10.1046/j.1365-201x.2002.00955.x.

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Wilson, Sarah N., Krisangel López, Sheryl Coutermash-Ott, Dawn I. Auguste, Danielle L. Porier, Philip M. Armstrong, Theodore G. Andreadis, Gillian Eastwood, and Albert J. Auguste. "La Crosse Virus Shows Strain-Specific Differences in Pathogenesis." Pathogens 10, no. 4 (March 29, 2021): 400. http://dx.doi.org/10.3390/pathogens10040400.

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La Crosse virus (LACV) is the leading cause of pediatric viral encephalitis in North America, and is an important public health pathogen. Historically, studies involving LACV pathogenesis have focused on lineage I strains, but no former work has explored the pathogenesis between or within lineages. Given the absence of LACV disease in endemic regions where a robust entomological risk exists, we hypothesize that some LACV strains are attenuated and demonstrate reduced neuroinvasiveness. Herein, we compared four viral strains representing all three lineages to determine differences in neurovirulence or neuroinvasiveness using three murine models. A representative strain from lineage I was shown to be the most lethal, causing >50% mortality in each of the three mouse studies. However, other strains only presented excessive mortality (>50%) within the suckling mouse neurovirulence model. Neurovirulence was comparable among strains, but viruses differed in their neuroinvasive capacities. Our studies also showed that viruses within lineage III vary in pathogenesis with contemporaneous strains, showing reduced neuroinvasiveness compared to an ancestral strain from the same U.S. state (i.e., Connecticut). These findings demonstrate that LACV strains differ markedly in pathogenesis, and that strain selection is important for assessing vaccine and therapeutic efficacies.
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Hammes, Frederik, Nico Boon, Johan de Villiers, Willy Verstraete, and Steven Douglas Siciliano. "Strain-Specific Ureolytic Microbial Calcium Carbonate Precipitation." Applied and Environmental Microbiology 69, no. 8 (August 2003): 4901–9. http://dx.doi.org/10.1128/aem.69.8.4901-4909.2003.

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ABSTRACT During a study of ureolytic microbial calcium carbonate (CaCO3) precipitation by bacterial isolates collected from different environmental samples, morphological differences were observed in the large CaCO3 crystal aggregates precipitated within bacterial colonies grown on agar. Based on these differences, 12 isolates were selected for further study. We hypothesized that the striking differences in crystal morphology were the result of different microbial species or, alternatively, differences in the functional attributes of the isolates selected. Sequencing of 16S rRNA genes showed that all of the isolates were phylogenetically closely related to the Bacillus sphaericus group. Urease gene diversity among the isolates was examined by using a novel application of PCR-denaturing gradient gel electrophoresis (DGGE). This approach revealed significant differences between the isolates. Moreover, for several isolates, multiple bands appeared on the DGGE gels, suggesting the apparent presence of different urease genes in these isolates. The substrate affinities (Km ) and maximum hydrolysis rates (V max) of crude enzyme extracts differed considerably for the different strains. For certain isolates, the urease activity increased up to 10-fold in the presence of 30 mM calcium, and apparently this contributed to the characteristic crystal formation by these isolates. We show that strain-specific calcification occurred during ureolytic microbial carbonate precipitation. The specificity was mainly due to differences in urease expression and the response to calcium.
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Kesavaraju, Banugopan, Ali Afify, and Randy Gaugler. "Strain Specific Differences in Intraspecific Competition inAedes albopictus(Diptera: Culicidae)." Journal of Medical Entomology 49, no. 5 (September 1, 2012): 988–92. http://dx.doi.org/10.1603/me11245.

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Ratneswaran, A., B. To, B. A. Russell, and F. Beier. "Strain and model specific differences in mouse models of osteoarthritis." Osteoarthritis and Cartilage 26 (April 2018): S71. http://dx.doi.org/10.1016/j.joca.2018.02.151.

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Ebmeyer, U., G. Keilhoff, G. Wolf, and W. Röse. "Strain specific differences in a cardio-pulmonary resuscitation rat model." Resuscitation 53, no. 2 (May 2002): 189–200. http://dx.doi.org/10.1016/s0300-9572(02)00003-5.

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Dilova, Ivanka, and Ted Powers. "Accounting for strain-specific differences duringRTGtarget gene regulation inSaccharomyces cerevisiae." FEMS Yeast Research 6, no. 1 (January 2006): 112–19. http://dx.doi.org/10.1111/j.1567-1364.2005.00008.x.

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Sarkar, Payel, and Pranav Danthi. "Determinants of Strain-Specific Differences in Efficiency of Reovirus Entry." Journal of Virology 84, no. 24 (October 13, 2010): 12723–32. http://dx.doi.org/10.1128/jvi.01385-10.

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ABSTRACT Cell entry of reovirus requires a series of ordered steps, which include conformational changes in outer capsid protein μ1 and its autocleavage. The μ1N fragment released as a consequence of these events interacts with host cell membranes and mediates their disruption, leading to delivery of the viral core into the cytoplasm. The prototype reovirus strains T1L and T3D exhibit differences in the efficiency of autocleavage, in the propensity to undergo conformational changes required for membrane penetration, and in the capacity for penetrating host cell membranes. To better understand how polymorphic differences in μ1 influence reovirus entry events, we generated recombinant viruses that express chimeric T1L-T3D μ1 proteins and characterized them for the capacity to efficiently complete each step required for membrane penetration. Our studies revealed two important functions for the central δ region of μ1. First, we found that μ1 autocleavage is regulated by the N-terminal portion of δ, which forms an α-helical pedestal structure. Second, we observed that the C-terminal portion of δ, which forms a jelly-roll β barrel structure, regulates membrane penetration by influencing the efficiency of ISVP* formation. Thus, our studies highlight the molecular basis for differences in the membrane penetration efficiency displayed by prototype reovirus strains and suggest that distinct portions of the reovirus δ domain influence different steps during entry.
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Ackland, G., R. Agrawal, C. Hou, and A. Patterson. "Strain-specific and pathogen-specific physiologic and genomic differences in murine inflammatory cardiac dysfunction." Critical Care 13, Suppl 1 (2009): P370. http://dx.doi.org/10.1186/cc7534.

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Dissertations / Theses on the topic "Strain-specific differences"

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Moertel, Luke Paul Frank, and mobileluke@hotmail com /. Luke Moertel@qimr edu au. "Microarray Analysis of the Schistosoma japonicum Transcriptome." Central Queensland University. Chemical and Biomedical Sciences, 2007. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20070705.120939.

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Schistosomiasis, a disease of humans caused by helminth parasites of the genus Schistosoma, kills 200 to 500 thousand people annually, endangering over 600 million people world-wide with 200 million people infected in 2003 [1, 2]. Three species of schistosome are primarily responsible for human infections, namely, Schistosoma haematobium, endemic to Africa, India, and the Middle East, S. mansoni, endemic to Africa / South America, and S. japonicum endemic to China and the Philippines [3]. The major pathological effects of schistosomiasis result from the deposition of parasite ova in human tissues and the subsequent intense granulomatous response induced by these eggs. There is a high priority to provide an effective sub-unit vaccine against these schistosome flukes, using proteins encoded by cDNAs expressed by the parasites at critical phases of their development. One technique that may expedite this gene identification is the use of microarrays for expression analysis. A 22,575 feature custom oligonucleotide DNA microarray designed from public domain databases of schistosome ESTs (Expressed Sequence Tags) was used to explore differential gene expression between the Philippine (SJP) and Chinese (SJC) strains of S. japonicum, and between males and females. It was found that 593, 664 and 426 probes were differentially expressed between the two geographical strains when mix sexed adults, male worms and female worms were compared respectively. Additionally, the study revealed that 1,163 male- and 1,016 female-associated probes were differentially expressed in SJP whereas 1,047 male- and 897 female-associated probes were differentially expressed in SJC [4]. Further to this, a detailed real time PCR expression study was used to explore the differential expression of eight genes of interest throughout the SJC life cycle, which showed that several of the genes were down-regulated in different life cycle stages. The study has greatly expanded previously published data of strain and gender-associated differential expression in S. japonicum. Further, the new data will provide a stepping stone for understanding the complexities of the biology, sexual differentiation, maturation, and development of human schistosomes, signaling new approaches for identifying novel intervention and diagnostic targets against schistosomiasis [4].
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Stacey, T., S. L. Prady, Melanie Haith-Cooper, S. Downe, N. Simpson, and K. E. Pickett. "Ethno-Specific Risk Factors for Adverse Pregnancy Outcomes: Findings from the Born in Bradford Cohort Study." 2016. http://hdl.handle.net/10454/7961.

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Objectives Preterm birth (PTB) and small for gestational age (SGA) are major causes of perinatal mortality and morbidity. Previous studies indicated a range of risk factors associated with these poor outcomes, including maternal psychosocial and economic wellbeing. This paper will explore a range of psycho-social and economic factors in an ethnically diverse population. Methods The UK’s Born in Bradford cohort study recruited pregnant women attending a routine antenatal appointment at 26–28 weeks’ gestation at the Bradford Royal Infirmary (2007–2010). This analysis includes 9680 women with singleton live births who completed the baseline questionnaire. Data regarding maternal socio-demographic and mental health were recorded. Outcome data were collected prospectively, and analysed using multivariate regression models. The primary outcomes measured were: PTB (<37 weeks’ gestation) and SGA (<10th customised centile). Results After adjustment for socio-demographic and medical factors, financial strain was associated with a 45 % increase in PTB (OR 1.45: 95 % CI 1.06–1.98). Contrary to expectation, maternal distress in Pakistani women was negatively associated with SGA (OR 0.65: CI 0.48–0.88). Obesity in White British women was protective for PTB (OR 0.67: CI 0.45–0.98). Previously recognized risk factors, such as smoking in pregnancy and hypertension, were confirmed. Conclusions This study confirms known risk factors for PTB and SGA, along with a new variable of interest, financial strain. It also reveals a difference in the risk factors between ethnicities. In order to develop appropriate targeted preventative strategies to improve perinatal outcome in disadvantaged groups, a greater understanding of ethno-specific risk factors is required
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Book chapters on the topic "Strain-specific differences"

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Sparks, Kate, and Cary L. Cooper. "Occupational Differences in the Work-Strain Relationship: Towards the Use of Situation-Specific Models." In From Stress to Wellbeing Volume 1, 315–26. London: Palgrave Macmillan UK, 2013. http://dx.doi.org/10.1057/9781137310651_15.

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Monk, Jonathan, and Emanuele Bosi. "Integration of Comparative Genomics with Genome-Scale Metabolic Modeling to Investigate Strain-Specific Phenotypical Differences." In Methods in Molecular Biology, 151–75. New York, NY: Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-7528-0_7.

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Kathariou, Sophia, Peter Evans, and Vikrant Dutta. "Strain-Specific Virulence Differences in Listeria monocytogenes: Current Perspectives in Addressing an Old and Vexing Issue." In Foodborne Pathogens, 61–92. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-56836-2_3.

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"Advances in Fisheries Bioengineering." In Advances in Fisheries Bioengineering, edited by David L. Smith, Mark A. Allen, and Ernest L. Brannon. American Fisheries Society, 2008. http://dx.doi.org/10.47886/9781934874028.ch4.

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Abstract<em>.</em>—Focal positions of drift-feeding salmonids are often proximate to higher velocities and may be characterized by velocity gradients. Velocity gradients result in distortion of the flow field through linear deformation and angular deformation, which are summarized as the normal and shear strain rates, respectively. The objective of our study was to use a metric termed the exposure strain rate to quantify velocity gradients used by juvenile spring Chinook salmon <em>Oncorhynchus tshawytscha </em>across habitat type, seasons, and spatial scales. Within a habitat type, focal and mean water column velocities were measured at the position of each fish. In addition, mean column velocities were measured 0.6 and 1.2 m laterally toward the center of the channel. Three exposure strain rates were calculated as the difference between focal and mean column velocity in the vertical scale and at 0.6 and 1.2 m lateral scale divided by the length of the smallest fish (0.4 cm) length scale for all seasons and habitat types. This allowed direct comparison of exposure strain rates for all sizes of fish. The data revealed that for Chinook salmon larger than 4 cm, the distribution of vertical exposure strain rates was similar across all habitat types by season. Exposure strain rates began to vary between habitat types for the lateral scale, reflecting hydraulic differences between reach-scale habitat features. We concluded that juvenile Chinook occupied a specific shear environment independent of reach-scale habitat. Exposure strain rates described microhabitat use in a manner reflecting the habitat occupancy model for drift-feeding salmonids. For this reason, exposure strain rates provide more specific information on habitat use than focal velocities alone.
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"Advances in Fisheries Bioengineering." In Advances in Fisheries Bioengineering, edited by David L. Smith, Mark A. Allen, and Ernest L. Brannon. American Fisheries Society, 2008. http://dx.doi.org/10.47886/9781934874028.ch4.

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Abstract<em>.</em>—Focal positions of drift-feeding salmonids are often proximate to higher velocities and may be characterized by velocity gradients. Velocity gradients result in distortion of the flow field through linear deformation and angular deformation, which are summarized as the normal and shear strain rates, respectively. The objective of our study was to use a metric termed the exposure strain rate to quantify velocity gradients used by juvenile spring Chinook salmon <em>Oncorhynchus tshawytscha </em>across habitat type, seasons, and spatial scales. Within a habitat type, focal and mean water column velocities were measured at the position of each fish. In addition, mean column velocities were measured 0.6 and 1.2 m laterally toward the center of the channel. Three exposure strain rates were calculated as the difference between focal and mean column velocity in the vertical scale and at 0.6 and 1.2 m lateral scale divided by the length of the smallest fish (0.4 cm) length scale for all seasons and habitat types. This allowed direct comparison of exposure strain rates for all sizes of fish. The data revealed that for Chinook salmon larger than 4 cm, the distribution of vertical exposure strain rates was similar across all habitat types by season. Exposure strain rates began to vary between habitat types for the lateral scale, reflecting hydraulic differences between reach-scale habitat features. We concluded that juvenile Chinook occupied a specific shear environment independent of reach-scale habitat. Exposure strain rates described microhabitat use in a manner reflecting the habitat occupancy model for drift-feeding salmonids. For this reason, exposure strain rates provide more specific information on habitat use than focal velocities alone.
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Furbish, David Jon. "Viscous Flows." In Fluid Physics in Geology. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195077018.003.0016.

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Most flow problems in geology involve viscous fluids which exhibit resistance to shearing motions. Mechanical treatments of such flows therefore must involve a consideration of frictional forces associated with this viscous behavior. Our first objective is to obtain a general equation of motion based on Newton’s second law that involves body and surface forces acting on a fluid element, regardless of the specific fluid involved. The steps in this development are similar to those leading to Euler’s equation for inviscid flows (Chapter 10); the difference is that tangential stresses acting on a fluid element, in addition to normal stresses, are included in the description of surface forces. It will be necessary, when describing normal forces, to distinguish between the thermodynamic pressure p, as used in treating inviscid flows, and a mechanical pressure σ0, which arises in treating viscous effects associated with compressible flows, and flows that simultaneously involve chemical reactions and possibly other phenomena. The second step in obtaining an equation of motion is determined by the specific fluid involved. Here we require a supplemental set of equations that describe the relation between surface forces and rates of fluid strain, as defined by the rate-of-strain tensor examined in Chapter 11. This set of equations, referred to as the constitutive equations of a fluid, varies with fluid rheology. The emphasis of this chapter is on Newtonian fluids. The set of constitutive equations in this case, when coupled with the general equation of motion obtained in the first step, lead to the well known Navier-Stokes equations. In addition, we will briefly examine the case of glacier ice as an example of a non-Newtonian fluid whose rheology is described by Glen’s law (Chapter 3). Treatments of viscous flows that incorporate conservation of energy similarly must involve a consideration of work performed against the frictional effects of viscosity. This performance of work against friction is nonconservative. Its effect therefore is to continuously extract mechanical energy from the main fluid motion, dissipating it in the form of heat. Our treatment of this irreversible conversion of energy will lead to a dissipation function that is added to the energy equation developed in Chapter 9.
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Rani, Manisha, Sushma Rajyalakshmi, Sunitha Pakalapaty, and Nagamani Kammilli. "Norovirus Structure and Classification." In Norovirus. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.98216.

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Norovirus are a major cause of acute gastroenteritis worldwide. Diarrheal disease is now the fourth common cause of mortality children under the age of 5 years but remain the 2nd most cause of morbidity. NoV are associated with 18% diarrheal diseases worldwide where rotavirus vaccinations has been successfully introduced. NoV has become major cause of gastroenteritis in children. NoV belong to family caliciviridae. They are non-enveloped, single stranded positive sense RNA Viruses. The genome consists of 3 Open reading frames, ORF-1 codes for non-structural protein, ORF-2 codes for major capsid protein VP1 and ORF-3 for minor capsid protein VP2. Based on sequence difference of the capsid gene (VP1), NoV have been classified in to seven genogroup GI-GVII with over 30 genotypes. Genogroups I, II, IV are associated with human infection. Despite this extensive diversity a single genotype GII.4 has been alone to be the more prevalent. Basic epidemiological disease burden data are generated from developing countries. NoV are considered fast evolving viruses and present an extensive diversity that is driven by acquisition of point mutations and recombinations. Immunity is strain or genotype specific with little or no protection conferred across genogroups. Majority of outbreaks and sporadic norovirus cases worldwide are associated with a single genotype, GII.4 which was responsible for 62% of reported NoV outbreaks in 5 continents from 2001 to 2007. GII.4 variants have been reported as major cause of global gastroenteritis pandemics starting in 1995 frequent emergence of novel GII.4 variants is known to be due to rapid evolution and antigenic variation in response to herd immunity. Novel GII.4 variants appear almost every 2 years. Recent GII.4 variant reported include Lordsdale 1996, Farmington Hills 2002, Hunter 2004, Yerseke 2006a, Den Haag 2006b, Apeldoon 2007, New Orleans 2009,most recently Sydney 2012. Detailed molecular epidemiologic investigation of NoV is associated for understanding the genetic diversity of NoV strain and emergence of novel NoV variants. However, reports have revealed that not all individuals develop symptoms and a significant proportion remains asymptomatic after NoV infections.
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Conference papers on the topic "Strain-specific differences"

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Hobart, Kathryn, Joshua Feinberg, Joshua Feinberg, Daniel Jones, and Daniel Jones. "INTEGRATING GEOCHEMICAL, MAGNETIC, AND GENOMIC ANALYSES TO UNDERSTAND STRAIN-SPECIFIC DIFFERENCES IN MICROBIALLY-MEDIATED PYRRHOTITE DISSOLUTION." In GSA Annual Meeting in Phoenix, Arizona, USA - 2019. Geological Society of America, 2019. http://dx.doi.org/10.1130/abs/2019am-337355.

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Berndt, A., AS Leme, LK Williams, SD Shapiro, and B. Paigen. "Sex Differences for Airway Hyper-Responsiveness (AHR) in a Mouse Strain Survey Lead to Identification of Sex-Specific Genetic Loci." In American Thoracic Society 2009 International Conference, May 15-20, 2009 • San Diego, California. American Thoracic Society, 2009. http://dx.doi.org/10.1164/ajrccm-conference.2009.179.1_meetingabstracts.a2760.

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Noban, M., and R. Adibi-Asl. "A Unified Approach for Comparison of Multiaxial Fatigue Models." In ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-98085.

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There are several methods of estimating fatigue crack initiation life under multiaxial loading including strain and energy based methods. This paper investigates a unified approach that enables comparison of these different models. The various fatigue models are mapped into a specific domain, i.e., stress, strain or energy domain. Three sets of experimental results available from literature are used for this comparison. Under simultaneous axial and torsional loadings, the fatigue life predictions of investigated fatigue models are in a better agreement when the axial load is more dominant than torsional loading. The differences in the predictions increase when torsional loading increases. This is mostly due to the fact that fatigue parameters are generally determined and calibrated under uniaxial cyclic loading.
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Hoursan, Hesam, and Mohammad Taghi Ahmadian. "Dynamic Behaviour of Ox Tibial and Femoral Bones: A Comparison With Human Bones." In ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-46555.

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Finite element models have been widely employed in an effort to quantify the stress and strain distribution around human bones as well as implanted prostheses and to explore the influence of these distributions on their long-term stability. In order to provide meaningful predictions, such models must contain an appropriate reflection of mechanical properties. Detailed geometrical and density information is now readily available from CT scanning. However, there are still many complications regarding patient-specific geometrical differences and bone dynamic behavior in-vivo. Experimental studies on animal bones, due to their convenience and accessibility, have always played a key role in simulating human bone behavior. In current study, a modal experiment has been done on an ox femoral and tibial bones and the results have been compared with those reported from human bones. Results have been obtained in terms of natural frequencies of medio-lateral bending mode shapes and damping ratios, and compared with those obtained by some previous studies. The results suggest similar pattern in modal behavior, but considerable difference between natural frequencies due to geometrical differences. To consider structural damping ratios, due to existence of moisture and marrow in bone in-vivo, samples have been obtained few hours post-mortem and the ratio has been extracted for each natural frequency. Finally, conclusions have been made on the similarity of the models and how to improve the FE models of human tibial and femoral components.
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Fissolo, Antoine, Se´bastien Amiable, Ludovic Vincent, Ste´phane Chapuliot, Andrei Constantinescu, and Jean Marc Stelmaszyk. "Thermal Fatigue Appears to be More Damaging Than Uniaxial Isothermal Fatigue: A Complete Analysis of the Results Obtained on the CEA Thermal Fatigue Device Splash." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93658.

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Thermal fatigue sometimes occurs in different types of nuclear reactor components. To estimate the crack initiation damage, uniaxial fatigue curves are often used. They were deduced from strain control tests using normalised cylindrical specimens. However, for in-service components, thermal loadings induce biaxial mechanical loadings. In that frame, the questioning of an eventual influence of the triaxiality factor on fatigue damage can be asked. To investigate differences between uniaxial fatigue damage and in service biaxial thermal fatigue damage, a campaign has been conducted on a specific thermal fatigue device (SPLASH). The specimen is continuously heated by Joule effect and cyclically cooled by a water spray. To deduce the thermo-mechanical state of the specimen, two uncoupled computations are performed: a thermal analysis and a mechanical analysis with the previous computed temperature field as a given loading parameter. All the computations have been performed using the object-oriented finite element code cast3M. All the analysed tests show clearly that initiation under thermal fatigue occurs before initiation under uniaxial isothermal fatigue: thermal fatigue is the most damaging case. Such difference is not due to difference on microscopic mechanisms for that temperature range. It results from a pure mechanical origin: a biaxial state corresponds to an increase of the hydrostatic stress.
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Mahboubi Nasrekani, Farid, Shymal Shivneel Kumar, and Sumesh Narayan. "Structural Dynamic Modification of Cylindrical Shells With Variable Thickness." In ASME 2020 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/pvp2020-21118.

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Abstract In this paper, the effects of some geometrical parameters on dynamic behavior of cylindrical shells with constant and variable thickness are studied. The equation of motion for the shell with constant thickness is extracted based on classical shell theory using Hamilton’s principle. These equations which are a system of coupled partial differential equations are solved analytically and the natural frequency is determined for cylindrical shells with constant thickness. The natural frequency for cylindrical shells with variable thickness is determined using finite element method by employing ANSYS. The results are compared and the effect of different geometric parameters such as length, thickness, and radius on natural frequency is discussed. The specific ranges for geometric parameters have been determined in which there is no significant difference between shells with constant or variable thickness. Cylindrical shells with variable thickness have better stress and strain distribution and optimum weight, in compare with the shells with constant thickness and it is important to know in which ranges of dimensions and geometrical parameters, there are some significant differences between their mechanical properties such as natural frequency. The results are compared with some other references.
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Slomka, Noa, and Amit Gefen. "Cell-to-Cell Variability in Tensile Strains Occurring in the Plasma Membrane and Nuclear Surface Area of Compressed Myoblasts." In ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53234.

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Confocal-microscopy-based three-dimensional (3D) cell-specific finite element (FE) modeling has recently been introduced by our group as a method to simulate the structural behavior of realistic cell geometries under external loading, while considering details of intracellular organelle [1,2]. This method provides comprehensive knowledge regarding cellular mechanics problems, for example, it is useful in the context of understanding the aetiology of deep tissue injury (DTI) — a type of a serious pressure ulcer associated with sustained cellular deformations [3–6]. In this regard, we previously postulated that sustained deformations of soft tissues near bony prominences could cause cell death by a mechanism of locally stretching cells, the consequence of which being that the permeability of the plasma membrane and nuclear surface area (NSA) in the affected cells increases. This, in turn, pathologically changes cell-matrix and intracellular transport profiles and eventually disrupts cellular homeostasis [1,7]. We hypothesize that tensile strains in the plasma membrane and NSA might differ in magnitude and pattern across externally-loaded individual cells of the same cell type, due to cell-to-cell morphological differences. Hence, in this study, we utilize confocal-based cell-specific 3D modeling to analyze tensile strain states in the plasma membrane and NSA of 3 different skeletal muscle cells (myoblasts) subjected to compression. We were specifically interested in chacterizing cell-to-cell variability in magnitudes and patterns of the localized strains.
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Almeida, C. A. "An Effective Adaptive Procedure in Nonlinear Finite Element Analysis." In ASME 1995 15th International Computers in Engineering Conference and the ASME 1995 9th Annual Engineering Database Symposium collocated with the ASME 1995 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1995. http://dx.doi.org/10.1115/cie1995-0746.

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Abstract A methodology initially proposed for authomatic mesh generation of triangular and quadrilateral finite element discretizations in linear two-dimension problems is now extended to material nonlinear analysis. The technique, which is based on a h-adaptive process, is capable of achieving a specified discretization density using a powerful mesh generator. The element solutions at the nodes are obtained through a general stress recovery procedure employing an a posteriori error estimator. The constitutive equation is approached in the formulation using a flow theory to describe the elasto-plastic material behavior. In this study the von Mises condition is employed for the state of multiaxial stress corresponding to the start of plastic flow, the normality condition furnishes a flow rule in the plastic strain increments subsequent to yielding and the kinematic hardening is assumed as hardening rule. The adaptive procedure is based on the complete mesh regeneration and specific mesh requirements (boundary conditions, geometry definitions and space node function), and aims for an optimality condition with the least number of elements that yields an uniform error distribution in all elements. In the stress recovery process the nodal values are assumed to belong to a polinomial expansion defined over patches of elements adjoining a particular assembly node considered. The nodal point parameters, at each element, are obtained using a least square fit of superconvergent sampling points existing in the patch. The material uniaxial elasto-plastic constitutive behavior is represented using overlays, defined over small strain increments, allowing for the representation of the material kinematic hardening behavior beyond the classical bilinear relation. The procedure error estimation is obtained from differences between the post-processed stress gradients and those from the finite element solutions. The energy error norm associated with stress field diferences and the finite element strain energy gives an effective error estimate, used for comparison with the process tolerance. Evaluation of the proposed technique is presented through two numerical sampling analyses that illustrate its applicability in the improvement of the solution accurance of general two-dimension finite element model solutions.
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9

Aumuller, John J., Zihui Xia, and Feng Ju. "Application of Elastic-Plastic Methods to Delayed Coker Drum Design." In ASME 2011 Pressure Vessels and Piping Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/pvp2011-57275.

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Coke drums are pressure vessels that are used in oil sands and conventional refinery processing industries for the thermal cracking of reduced bitumen to recover additional, saleable gas and liquid product streams. The drums are constructed to the requirements of ASME VIII Division 1 although they are in a low cycle thermal-mechanical service environment. Recent practice has been to introduce design by analysis considerations from ASME VIII Division 2 even though service temperatures of the actual equipment exceed the design limits of the Code. In this paper, simplified elastic-plastic analysis models are developed for assessment of the stress and strain levels in coke drums during specific operational phases. One model is applied for determination of the local stress caused by differences in the coefficients of thermal expansion between the clad liner and base materials. Because clad construction is used throughout the vessel, the impact is extensive. Consideration is given to the general stresses induced by the cyclical, progressive dilation and contraction action of the drum shell caused by axial thermal gradients. Another model estimates hot and cold spot formation and the development of localized stress / strain distributions in coke drums. The resulting thermal stresses include the local stress from suppression of differential expansion between clad and base material, thermal bending stresses and local thermal stresses from hot and cold spot formation. It is found that the evaluation of these loads on drum cracking aligns with industry survey results. Better understanding of these loads has impact on materials selection and fabrication procedures for new drums and repair of existing drums. Operational considerations can also be identified to help improve drum reliability.
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10

Gross, David J., Thomas C. Ligon, and John C. Minichiello. "Vessel Design for Unintended Detonation: A Comparison of Alternative Code Rules." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63685.

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The Hanford Tank Waste Treatment and Immobilization Plant (WTP) will process waste slurries that have the potential to generate flammable gases and will utilize a number of atmospheric vessels to store these slurries at various stages of the waste treatment process. Throughout the design process, provisions have been made to ensure that these flammable gasses are vented from these vessels and to eliminate potential sources of ignition. However, Bechtel National, Inc. (BNI) would like to be able to demonstrate that these vessels are capable of withstanding a limited number of unintended detonations. It is well known that pressure vessels may be designed for internal detonations. However, these loadings tend to cause very brief transients of high stress that can make traditional stress-based design rules to be difficult to meet. In the past decade, a number of strain-based design methodologies have become available, including ASME Boiler and Pressure Vessel Code (BPVC), Section VIII, Division 2, Part 5; ASME Section VIII, Division 3; ASME Section VIII, Division 3 Code Case 2564; and API 579-1 / ASME FFS-1. Each of these sets of rules permits some degree of plasticity in vessel design, but there are key differences in the specific provisions. In this paper, the use of these different sets of Code rules will be demonstrated in the context of the design of a WTP vessel for a single unintended detonation, and the advantages and disadvantages of these alternative design approaches will be discussed.
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