Готові списки джерел за темами / Strain mechanisms

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Добірка наукової літератури з теми "Strain mechanisms"

Автор: Grafiati
Опубліковано: 23 вересня 2022

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Статті в журналах з теми "Strain mechanisms"

1

Martcheva, Maia, Benjamin M. Bolker, and Robert D. Holt. "Vaccine-induced pathogen strain replacement: what are the mechanisms?" Journal of The Royal Society Interface 5, no. 18 (April 25, 2007): 3–13. http://dx.doi.org/10.1098/rsif.2007.0236.

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Host immune systems impose natural selection on pathogen populations, which respond by evolving different antigenic signatures. Like many evolutionary processes, pathogen evolution reflects an interaction between different levels of selection; pathogens can win in between-strain competition by taking over individual hosts (within-host level) or by infecting more hosts (population level). Vaccination, which intensifies and modifies selection by protecting hosts against one or more pathogen strains, can drive the emergence of new dominant pathogen strains—a phenomenon called vaccine-induced pathogen strain replacement . Here, we review reports of increased incidence of subdominant variants after vaccination campaigns and extend the current model for pathogen strain replacement, which assumes that pathogen strain replacement occurs only through the differential effectiveness of vaccines against different pathogen strains. Based on a recent theoretical study, we suggest a broader range of possible mechanisms, some of which allow pathogen strain replacement even when vaccines are perfect —that is, they protect all vaccinated individuals completely against all pathogen strains. We draw an analogy with ecological and evolutionary explanations for competitive dominance and coexistence that allow for tradeoffs between different competitive and life-history traits.
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2

Xiong, Hao, and Xiumin Diao. "Stiffness analysis of cable-driven parallel mechanisms with cables having large sustainable strains." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 10 (January 24, 2020): 1959–68. http://dx.doi.org/10.1177/0954406220902165.

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A cable-driven parallel mechanism is driven by a group of cables. Cable-driven parallel mechanisms can use various cables (e.g. steel cables, nylon cables, isoprene rubber cables, and extension springs) with different sustainable strains. This paper studies the stiffness of cable-driven parallel mechanisms with cables having large sustainable strains, aiming to achieve significantly adjustable overall stiffness. The overall stiffness of a cable-driven parallel mechanism can be decomposed into the constant base stiffness and the adjustable strain stiffness. This paper proposes and mathematically proves a theorem that guarantees that the overall stiffness of a cable-driven parallel mechanism at an arbitrary stable pose can be dominated by the adjustable strain stiffness when cable strains are larger than 100%. The theorem employs the minimum eigenvalues of stiffness matrices to characterize the stiffness of cable-driven parallel mechanism. The theorem provides a sufficient condition that guarantees that the overall stiffness of a cable-driven parallel mechanism at an arbitrary stable pose can be significantly adjusted (i.e. the adjustable strain stiffness contributes more than the constant base stiffness in determining the overall stiffness). The theorem is verified through the simulation of a cable-driven parallel mechanism with six degrees of freedom and seven cables.
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3

Cheng, Yi-Hsiang, Tzu-Wen Huang, Chih-Han Juan, Sheng-Hua Chou, Yao-Yi Tseng, Ting-Wen Chen, Tsuey-Ching Yang, and Yi-Tsung Lin. "Tigecycline-non-susceptible hypervirulent Klebsiella pneumoniae strains in Taiwan." Journal of Antimicrobial Chemotherapy 75, no. 2 (November 8, 2019): 309–17. http://dx.doi.org/10.1093/jac/dkz450.

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Abstract Objectives Emergent antimicrobial-resistant hypervirulent Klebsiella pneumoniae (hvKp) is an important public health issue. We aimed to investigate resistance mechanisms and hypervirulent traits among tigecycline-non-susceptible (TNS) K. pneumoniae clinical strains, focusing on one hvKp strain with in vivo evolution of tigecycline resistance. Methods TNS K. pneumoniae strains causing invasive diseases in a medical centre in Taiwan between July 2015 and April 2018 were collected. Resistance mechanisms were determined and hvKp strains were defined as rmpA/rmpA2-carrying strains. Isogenic strains with and without tigecycline resistance were subjected to WGS and in vivo virulence testing. Further, site-directed mutagenesis was used to confirm the resistance mechanism. Results In total, 31 TNS K. pneumoniae strains were isolated, including six hypervirulent strains. Tigecycline resistance mechanisms were mostly caused by overexpression of AcrAB and OqxAB together with up-regulation of RamA or RarA, respectively. One TNS hypervirulent strain (KP1692; MIC=6 mg/L) derived from its tigecycline-susceptible counterpart (KP1677; MIC=0.75 mg/L) showed acrAB overexpression. WGS revealed four genetic variations between KP1677 and KP1692. In addition, using site-directed mutagenesis, we confirmed that a 1 bp insertion in the ramA upstream region (RamR-binding site), leading to ramA and acrAB overexpression in KP1692, was responsible for tigecycline resistance. The in vivo virulence experiment showed that the TNS hvKp strain KP1692 still retained its high virulence compared with KP1677. Conclusions hvKp strains accounted for 19.4% among TNS strains. We identified alterations in the ramA upstream region as a mechanism of in vivo tigecycline resistance development in an hvKp strain.
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4

Sakai, Taku, and Hiromi Miura. "Mechanisms of Ultrafine Grain Formation in Severe Plastic Deformation." Materials Science Forum 638-642 (January 2010): 98–103. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.98.

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The evolution mechanisms of ultrafine grains processed by severe plastic deformation are studied in ferritic steel, copper and aluminum alloys. The structural changes are characterized by the evolution of deformation bands such as microshear bands (MSBs) at moderate strains. The process of strain-induced grain formation can be subdivided in the following three stages irrespective of deformation temperature: i.e. an incubation period for new grain evolution in low strain; grain fragmentation by frequent development of MSBs in medium strain, and a full development of new grains in large strain. A mechanism of new grain formation during SPD, i.e. the MSB-based model, is proposed and discussed comparing with the subgrain-based model.
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5

Hong, P., G. B. Olson, and A. L. Roytburd. "Nucleation mechanisms for strain transformations." Acta Crystallographica Section A Foundations of Crystallography 49, s1 (August 21, 1993): c434. http://dx.doi.org/10.1107/s010876737808770x.

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THOMASEY, DOUGLAS H., and MAIA MARTCHEVA. "SEROTYPE REPLACEMENT OF VERTICALLY TRANSMITTED DISEASES THROUGH PERFECT VACCINATION." Journal of Biological Systems 16, no. 02 (June 2008): 255–77. http://dx.doi.org/10.1142/s0218339008002484.

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Strain replacement occurs when after a vaccination campaign one (or more) strains decline in prevalence while another strain (or strains) rise in prevalence. Differential effectiveness of the vaccine is the widely accepted and the most important mechanism which leads to this replacement effect. Recent theoretical studies have suggested that strain replacement may occur even if the vaccine is perfect, that is, the vaccine is completely effective with respect to all strains present. It has already been shown that perfect vaccination, along with a trade-off mechanism, such as co-infection or super-infection, lead to strain replacement. In this paper, we examine the hypothesis that strain replacement with perfect vaccination occurs only with trade-off mechanisms which allow a strain with a lower reproduction number to eliminate a strain with a higher reproduction number in the absence of vaccination. We test this hypothesis on a two-strain model with vertical transmission. We first show that vertical transmission as a trade-off mechanism can lead to dominance of a strain with suboptimal reproduction number. Based on the hypothesis we expect, and we show, that strain replacement occurs with vertical transmission.
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van Niel, Ed W. J., Johan Palmfeldt, Rani Martin, Marco Paese, and B�rbel Hahn-H�gerdal. "Reappraisal of the Regulation of Lactococcal l-Lactate Dehydrogenase." Applied and Environmental Microbiology 70, no. 3 (March 2004): 1843–46. http://dx.doi.org/10.1128/aem.70.3.1843-1846.2004.

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ABSTRACT Lactococcal lactate dehydrogenases (LDHs) are coregulated at the substrate level by at least two mechanisms: the fructose-1,6-biphosphate/phosphate ratio and the NADH/NAD ratio. Among the Lactococcus lactis species, there are strains that are predominantly regulated by the first mechanism (e.g., strain 65.1) or by the second mechanism (e.g., strain NCDO 2118). A more complete model of the kinetics of the regulation of lactococcal LDH is discussed.
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Kaatz, G. W., and S. M. Seo. "Mechanisms of fluoroquinolone resistance in genetically related strains of Staphylococcus aureus." Antimicrobial Agents and Chemotherapy 41, no. 12 (December 1997): 2733–37. http://dx.doi.org/10.1128/aac.41.12.2733.

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Fluoroquinolone resistance in Staphylococcus aureus results from amino acid substitutions at particular locations in the DNA gyrase A and B subunits as well as in the topoisomerase IV A subunit and from NorA-mediated efflux. More than one resistance mechanism may be present in a single strain. Fluoroquinolone-resistant derivatives of SA-1199, a methicillin-susceptible S. aureus strain, were selected in vivo or in vitro, and their mechanisms of fluoroquinolone resistance were identified. We found that many of the resistance mechanisms described above can develop in derivatives of a single parent strain, either singly or in combination, and can arise in a single step. Variances in MICs for strains with the same apparent resistance mechanisms likely are due to the presence of new or undetected but established means of fluoroquinolone resistance. NorA-mediated resistance can occur in the apparent absence of topoisomerase mutations and in some strains may be the result of a promoter region mutation causing increased expression of norA. However, increased expression of norA can occur independently of this mutation, suggesting that a regulatory locus for this gene exists elsewhere on the chromosome.
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Rocque, Michael. "Strain, coping mechanisms, and slavery: a general strain theory application." Crime, Law and Social Change 49, no. 4 (March 18, 2008): 245–69. http://dx.doi.org/10.1007/s10611-008-9106-8.

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Zhang, Xu-Sheng, and Ke-Fei Cao. "The Impact of Coinfections and Their Simultaneous Transmission on Antigenic Diversity and Epidemic Cycling of Infectious Diseases." BioMed Research International 2014 (2014): 1–23. http://dx.doi.org/10.1155/2014/375862.

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Epidemic cycling in human infectious diseases is common; however, its underlying mechanisms have been poorly understood. Much effort has been made to search for external mechanisms. Multiple strains of an infectious agent were usually observed and coinfections were frequent; further, empirical evidence indicates the simultaneous transmission of coinfections. To explore intrinsic mechanisms for epidemic cycling, in this study we consider a multistrain Susceptible-Infected-Recovered-Susceptible epidemic model by including coinfections and simultaneous transmission. We show that coinfections and their simultaneous transmission widen the parameter range for coexistence and coinfections become popular when strains enhance each other and the immunity wanes quickly. However, the total prevalence is nearly independent of these characteristics and approximated by that of one-strain model. With sufficient simultaneous transmission and antigenic diversity, cyclical epidemics can be generated even when strains interfere with each other by reducing infectivity. This indicates that strain interactions within coinfections and cross-immunity during subsequent infection provide a possible intrinsic mechanism for epidemic cycling.
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Дисертації з теми "Strain mechanisms"

1

Johnson, David Thomas. "Deformation mechanisms in ABS polymers." Thesis, Cranfield University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341042.

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Turner, Stephen George. "Strain relaxation mechanisms and stress-balancing of SiGe heterostructures." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491115.

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Until now, progress of the microelectronic industry has been maintained by scaling devices. Physical limits now necessitate alternative approaches such as enhancing material properties through strain engineering or increasing functionality through use of Si/SiGe heterostructures (e.g. optoelectronic integration), requiring control of strain, which may enhance electrical properties but can also lead to deleterious structural and electronic effects. Strain can be controlled via growth of stress-balanced structures on a fully strain relaxed virtual substrate (VS) which acts as a growth template for, and maintains strain in, the active layers, which need to be ordered and defect free. The crystalline quality of the VS therefore impacts directly upon the device. These basic elements are realised in a molecular beam epitaxy system using gaseous hydride precursors. Compositionally graded VS are used to investigate strain-relaxation processes. High resolution x-ray diffraction (XRD) allowed examination of lattice reciprocal space, where compositional and strain information is dispersed. Localised distortions of the lattice revealed the mosaic nature of the structure. Nomarski contrast microscopy and atomic force microscopy enabled quantitative analysis of surface defects and roughness, including characteristic crosshatch. VS grading rates, growth temperatures and precursor fluxes were varied to assess relaxation kinetics. The nucleation and propagation of strain-relieving dislocations were investigated through the growth of different VS structures on vicinal Si(001) substrates. XRD analysis showed tilting of the epitaxial layer with respect to the substrate. A correlation of tilt angle with offcut angle was observed, following energy barrier asymmetries on the available slip systems. Development of the tilt was seen to be a non-linear function of both Ge composition and grading rate, and was explained by interdislocation interactions. Stress-balancing was investigated by designing distributed Bragg reflector stacks. Structures without detrimental strain relief were achieved, with a reflectance in excess of those reported in the literature, demonstrating the applicability of the VS growth and stress-balance methods. The elastic properties of SiGe could also be probed via this approach, and small deviations from linear interpolation of bulk Si and Ge values were found, supported by theoretical modelling.
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Krasner, Paul. "Strain Localization Mechanisms in the Scituate Granite, Rhode Island." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1497285708350254.

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Xu, Lili Sh D. Massachusetts Institute of Technology. "High temperature deformation mechanisms and strain heterogeneities in calcite rocks." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45602.

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Анотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2008.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Page 238 blank.
Includes bibliographical references.
In nature, carbonates often accumulate large amounts of strain in localized shear zones. Such marble sequences play a key role in crustal deformation processes. Despite extensive field and laboratory investigation, many questions remain concerning the mechanical behavior of these rocks. For example, the mechanical behavior of different limestones and marbles differ greatly, possibly owing to the presence of chemical impurities or solid-solutes. Thus, Chapter 2 examines the effect of Mg solute, a common impurity, on the mechanical behavior of calcite rocks. The results indicate that increasing Mg content increases the strength of calcite rocks during dislocation creep. The anisotropic nature of crystal slip usually entails variations in reorientation of individual grains and heterogeneous deformation within the polycrystalline material. In Chapter 3, a new technique including a series of sample preparation and image analysis algorithms is developed to provide quantitative measurements of the scale of heterogeneities produced, and to gain fundamental insight into polycrystalline plasticity. We place particular attention on quantifying variations of strain within grain interiors and at grain boundaries, and on recognizing the relative activities of different slip systems. The quantification of grain-to-grain interactions during straining is relevant for the improvement and verification of models of polycrystalline plasticity. The strain measurements obtained from Chapter 3 are compared with predictions of grain strain and reorientation obtained from the self-consistent viscoplastic method (Chapter 4). The results suggest that the self-consistent model gives a good description of global texture, but does not always predict lattice rotation and deformation within individual grains. To predict the actual deformation of individual grains will require a quantitative consideration of the effects on local strain of grain-boundary misorientation, local strain/stress state, grain-boundary sliding, and deviations in grain geometry.
by Lili Xu.
Ph.D.
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Adelmann, Hans Christoph. "Growth and strain relaxation mechanisms of group III nitride heterostructures." Université Joseph Fourier (Grenoble), 2002. http://www.theses.fr/2002GRE10039.

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Ce travail a porté sur les mécanismes de croissance épitaxiale et de relaxation de contrainte d'hétérostructures de nitrures d'éléments III, GaN et AIN, en épitaxie par jets moléculaires assistée par plasma d'azote. Nous avons étudié les structures de la surface (0001) de GaN et d'AIN en conditions d'excès de métal. Nous avons montré que la quantité de Ga absorbée sur GaN peur être évaluée par RHEED. Cette méthode a été appliquée à l'absorption de Ga et à la croissance de GaN en conditions riche Ga. Dans les deux cas, les résultats ont permis de tracer un diagramme qui décrit la quantité de Ga présente sur GaN en fonction du flux de Ga et de la température de croissance. Les morphologies de surface obtenues après la croissance de GaN dans les différentes parties du diagramme sont discutées. Nous avons ensuite abordé la relaxation des contraintes d'hétérostructures GaN/AIN. En conditions d'excès d'azote, la relaxation se produit de façon élastique, soit par la formation d'îlots plats à basse température, soit par la formation d'îlots pyramidaux selon le mode Stranski-Krastanow à haute température. En conditions d'excès de métal, la croissance est bidimensionnelle et la relaxation se produit par introduction de dislocations. Nous avons démontré que l'épaisseur critique de cette relaxation plastique dépend fortement des conditions de croissance. L'étude de la nucléation d'îlots de GaN sur AIN en mode Stranski-Krastanowa permis de contrôler leur taille et leur densité. Ces deux paramètres peuvent être variés de façon indépendante dans une large gamme de valeurs. Nous avons trouvé que l'optimisation de la distribution de taille des îlots est compliquée par une distribution bimodale à haute température. Finalement, nous avons étudié l'adsorption de Ga sur les surfaces (0001) d'AIN et d'AlGaN. Ceci a permis de démontrer la faisabilité d'épitaxie en flux alternés de GaN sur AIN et AlGaN.
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Degli, Alessandrini Giulia. "Deformation mechanisms and strain localization in the mafic continental lower crust." Thesis, University of Plymouth, 2018. http://hdl.handle.net/10026.1/12799.

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The rheology and strength of the lower crust play a key role in lithosphere dynamics, influencing the orogenic cycle and how plate tectonics work. Despite their geological importance, the processes that cause weakening of the lower crust and strain localization are still poorly understood. Through microstructural analysis of naturally deformed samples, this PhD aims to investigate how weakening and strain localization occurs in the mafic continental lower crust. Mafic granulites are analysed from two unrelated continental lower crustal shear zones which share comparable mineralogical assemblages and high-grade deformation conditions (T > 700 °C and P > 6 Kbar): the Seiland Igneous Province in northern Norway (case-study 1) and the Finero mafic complex in the Italian Southern Alps (case-study 2). Case-study 1 investigates a metagabbroic dyke embedded in a lower crustal metasedimentary shear zone undergoing partial melting. Shearing of the dyke was accompanied by infiltration of felsic melt from the adjacent partially molten metapelites. Findings of case-study 1 show that weakening of dry and strong mafic rocks can result from melt infiltration from nearby partially molten metasediments. The infiltrated melt triggers melt-rock reactions and nucleation of a fine-grained (< 10 µm average grain size) polyphase matrix. This fine-grained mixture deforms by diffusion creep, causing significant rheological weakening. Case-study 2 investigates a lower crustal shear zone in a compositionally-layered mafic complex made of amphibole-rich and amphibole-poor metagabbros. Findings of case-study 2 show that during prograde metamorphism (T > 800 °C), the presence of amphibole undergoing dehydration melting reactions is key to weakening and strain localization. Dehydration of amphibole generates fine-grained symplectic intergrowths of pyroxene + plagioclase. These reaction products form an interconnected network of fine-grained (< 20 µm average grain size) polyphase material that deforms by diffusion creep, causing strain partitioning and localization in amphibole-rich layers. Those layers without amphibole fail to produce an interconnected network of fine grained material. In this layers, plagioclase deforms by dislocation creep, and pyroxene by microfracturing and neocrystallization. Overall, this PhD research highlights that weakening and strain localization in the mafic lower crust is governed by high-T mineral and chemical reactions that drastically reduce grain size and trigger diffusion creep.
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Da, Re Gregory 1970. "Physical mechanisms controlling the pre-failure stress-strain behavior of frozen sand." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/31088.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.
Includes bibliographical references.
The physical mechanisms controlling the pre-failure stress-strain behavior of frozen sands are investigated in triaxial compression. The pre-failure, or small strain behavior (Eaby Gregory Da Re.
Ph.D.
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8

Allred, Jacob D. "An Investigation into the Mechanisms of Formation of the Hard Zone in FSW X65." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3806.

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Friction stir welding (FSW) of HSLA steel commonly produces a hard zone (HZ) on the advancing side (AS) of the weld. Despite its detrimental effects on weld toughness, the mechanisms of its formation have not been thoroughly investigated and are not well understood. This paper investigates the various mechanisms in FSW believed to affect the weld HZ, namely: strain, strain-rate, peak temperature and cooling rate. Gleeble tests indicate that strain and strain rate have negligible effects on weld HZ with cooling rate and peak temperature as dominant effects. Jominy tests resulted in cooling rate having 270% greater influence than peak temperature on the formation of lath ferrite microstructures similar to what is observed in the HZ of FSW X65. Comparing weld HZ microstructures to Jominy tests, it is estimated that cooling rates on the AS of the weld are at least 150°C/s higher than the retreating side. Reducing the cooling rate on the AS will likely lead to an improved microstructure at the weld HZ.
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9

Acosta, Matias [Verfasser], Jürgen [Akademischer Betreuer] Rödel, and Wolfgang [Akademischer Betreuer] Donner. "Strain Mechanisms in Lead-Free Ferroelectrics for Actuators / Matias Acosta ; Jürgen Rödel, Wolfgang Donner." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2015. http://d-nb.info/1122286163/34.

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Aldea, Maria Ramona. "Identification of novel regulatory mechanisms controlling heterocyst development in Anabaena Sp. strain PCC 7120." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2996.

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Книги з теми "Strain mechanisms"

1

Acosta, Matias. Strain Mechanisms in Lead-Free Ferroelectrics for Actuators. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-27756-1.

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2

Owen, Grace M. Taking the strain: An annual review of literature relating to stress, coping mechanisms and support systems for professional carers. 5th ed. [Surrey]: National Association for Staff Support Within the Health Care Services, 1993.

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3

W, Dally James, ed. Experimental solid mechanics. Knoxville, Tenn: College House Enterprises, 2010.

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4

Berger, John R. Study of static and dynamic fracture using strain measurements. Boulder, Colo: U.S. Dept. of Commerce, National Institute of Standards and Technology, 1990.

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5

Chung, R. M. Development of an NBS polymer gage for dynamic soil stress measurement. Gaithersburg, MD: U.S. Dept. of Commerce, National Bureau of Standards, 1985.

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6

Berger, John R. Study of static and dynamic fracture using strain measurements. Boulder, Colo: U.S. Dept. of Commerce, National Institute of Standards and Technology, 1990.

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7

Veli-Tapani, Kuokkala, ed. Plastic deformation and strain hardening. Enfield, N.H: Trans Tech, 2002.

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8

Liang, Hong, and George E. Totten. Surface modification and mechanisms: Friction, stress and reaction engineering. New York: Marcel Dekker, 2004.

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9

Tandanand, Sathit. Determining horizontal displacement and strains due to subsidence. Washington, D.C. (2401 E St., N.W., MS #9800, Washington 20241-0001): United States Dept. of the Interior, Bureau of Mines, 1991.

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10

Kitamura, Takayuki. A nonlinear high temperature fracture mechanics basis for strainrange partitioning. [Washington, DC]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Division, 1990.

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Частини книг з теми "Strain mechanisms"

1

Souza, Leticia O., Lourdes M. S. Souza, and Flávio A. Silva. "Mechanics and Cracking Mechanisms in Natural Curauá Textile Reinforced Concrete." In Strain-Hardening Cement-Based Composites, 359–66. Dordrecht: Springer Netherlands, 2017. http://dx.doi.org/10.1007/978-94-024-1194-2_42.

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Bao, Wan-Ning. "Mediating Mechanisms of Strain and Delinquency." In Delinquent Youth in a Transforming China, 113–38. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-63727-3_4.

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Bao, Wan-Ning. "Coping Mechanisms for Strain and Delinquency." In Delinquent Youth in a Transforming China, 139–80. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-63727-3_5.

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King, Geoffrey C. P., and Charles G. Sammis. "The Mechanisms of Finite Brittle Strain." In Fractals and Chaos in the Earth Sciences, 611–40. Basel: Birkhäuser Basel, 1992. http://dx.doi.org/10.1007/978-3-0348-6191-5_6.

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Ross, C. Allen. "Fracture of Concrete at High Strain-Rate." In Toughening Mechanisms in Quasi-Brittle Materials, 577–96. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3388-3_35.

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Granacher, J., and A. Scholz. "Creep-Fatigue Behaviour under Service-Type Strain Cycling." In Fatigue under Thermal and Mechanical Loading: Mechanisms, Mechanics and Modelling, 209–14. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-015-8636-8_22.

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Russhard, Peter. "The Rise and Fall of the Rotor Blade Strain Gauge." In Mechanisms and Machine Science, 27–37. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-09918-7_2.

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Okrajni, J. "Modelling of the Stress-Strain Behaviour of Metal Moulds." In Fatigue under Thermal and Mechanical Loading: Mechanisms, Mechanics and Modelling, 457–66. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-015-8636-8_47.

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Pinto, Manuel, Nicola Roveri, Gianluca Pepe, Andrea Nicoletti, Gabriele Balconi, and Antonio Carcaterra. "Extraction of the Beam Elastic Shape from Uncertain FBG Strain Measurement Points." In Mechanisms and Machine Science, 362–69. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-03320-0_39.

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Christ, H. J., H. Mughrabi, S. Kraft, F. Petry, R. Zauter, and K. Eckert. "The Use of Plastic Strain Control in Thermomechanical Fatigue Testing." In Fatigue under Thermal and Mechanical Loading: Mechanisms, Mechanics and Modelling, 1–14. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-015-8636-8_1.

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Тези доповідей конференцій з теми "Strain mechanisms"

1

Liu, R. "Strain Relaxation Mechanisms in InGaN Epilayers." In PHYSICS OF SEMICONDUCTORS: 27th International Conference on the Physics of Semiconductors - ICPS-27. AIP, 2005. http://dx.doi.org/10.1063/1.1994070.

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Sajeva, A., and S. Capaccioli. "Strain Accumulation Mechanisms in Unconsolidated Sediments during Compression." In 80th EAGE Conference and Exhibition 2018. Netherlands: EAGE Publications BV, 2018. http://dx.doi.org/10.3997/2214-4609.201800916.

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3

Mehta, Vipul, Mary Frecker, and George Lesieutre. "Stress Relief in Contact-Aided Cellular Compliant Mechanisms." In ASME 2008 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2008. http://dx.doi.org/10.1115/smasis2008-431.

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Cellular structures with an internal contact-mechanism are investigated. These contact-aided compliant mechanisms are shown to reduce the local tensile stresses, thereby providing additional global strain before yielding or fracture failure compared to honeycomb or auxetic cellular structures. An analytical model for such structures is developed and it is validated using FEA simulations. Two different materials are considered for comparison. More than 100% improvement in global strain capability is possible using the contact. A high-strain morphing aircraft skin is examined as an application of these mechanisms. The contact-aided cellular compliant mechanisms are more advantageous in terms of both the structural mass as well as the global strain compared to a non-contact design. In the application considered the stress-relief mechanism increased the global strain capability by as high as 37%.
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4

Dong, Q., Y. Gu, and B. Y. Hu. "Progress on Mechanisms of the Strain Growth Phenomenon in Containment Vessels." In ASME 2012 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/pvp2012-78104.

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Strain growth is a phenomenon observed in the elastic response of containment vessels subjected to internal blast loading. The local response of the vessel may become larger in a later stage than its breathing mode response during the initial stage. The strain growth phenomenon has attracted great attention since it was first observed in 1976, and numerous researches have been conducted to investigate the mechanisms of the strain growth phenomenon in containment vessels. In this paper, some typical results on studying the mechanisms of strain growth in cylindrical and spherical containment vessels will be given, and the discovery of the mechanism of nonlinear modal coupling is especially highlighted. The present review may provide a good understanding on the dynamic response characteristics of cylindrical and spherical containment vessels subjected to internal blast loading.
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Subhash, Ghatu, Brian J. Koeppel, Richard J. Anton, Yonggang Y. Huang, and Abhijit Chandra. "High Strain Rate Normal Indentation of Ceramics: Implications for Material Removal Mechanisms." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0695.

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Abstract The static indentation fracture mechanics approach does not fully capture the rate sensitive nature of failure behavior in ceramics. Accordingly, a dynamic indentation technique was developed to investigate material removal mechanisms at strain rates similar to those encountered in realistic grinding situations. The technique is designed to deliver a single indentation load of duration 100 microseconds. Compared to static loading, it is observed that lateral cracking is promoted under dynamic loading rates. The implications of dynamic loading on the material removal mechanisms are discussed.
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6

Torres, James, Devin Neal, and H. Harry Asada. "A PZT Array Actuator Using Buckling Strain Amplification and Preload Mechanisms." In ASME 2011 Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power and Motion Control. ASMEDC, 2011. http://dx.doi.org/10.1115/dscc2011-6070.

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Displacement amplification mechanisms have been a topic of research for piezoelectric actuators for decades to overcome their significantly small strain, but still utilize their high power density, force, and efficiency. This paper further analyzes a nonlinear buckling mechanism to improve its efficiency, defined as the ratio of mechanical work output of the buckling actuator to the mechanical work output of the PZT actuator, as well as, employing two methods, preload and loading conditions, that improve its work output per cycle. This is accomplished by running a numerical analysis of the geometry of the flexure joints in the buckling mechanism which found a maximum mechanical efficiency of 48%. The preload is applied using shape memory alloy wire to exploit the low stiffness of the super elastic regime; which in turn allows a larger work output due to a loading condition supplied by a novel gear design. Finally, a prototype was fabricated to provide a baseline of comparison against these concepts.
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Steinberg, Adam, James Driscoll, and Steven Ceccio. "Turbulence-Flame Interactions - The Mechanisms of Flame Strain and Wrinkling." In 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2008. http://dx.doi.org/10.2514/6.2008-4572.

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Nakamura, Yoshihiko. "Minimizing Object Strain Energy for Coordination of Multiple Robotic Mechanisms." In 1988 American Control Conference. IEEE, 1988. http://dx.doi.org/10.23919/acc.1988.4789771.

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Canfield, Shawn, and Mary I. Frecker. "Design of Compliant Mechanisms for Amplification of Induced Strain Actuators." In ASME 1999 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/detc99/dac-8602.

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Abstract The focus of this paper is on designing compliant mechanism amplifiers for piezoelectric actuators using a topology optimization approach. Two optimization formulations are developed: one in which the overall stroke amplification or geometric advantage (GA) is maximized, and another where the mechanical efficiency (ME) of the amplifier is maximized. Two solution strategies are used, Sequential Linear Programming (SLP) and an Optimality Criteria method, and results are compared with respect to computation time and mechanism performance. Design examples illustrate the characteristics of both problem formulations, and physical prototypes have been fabricated as proof of concept. An automated detail design procedure has also been developed which allows the topology optimization results obtained in MATLAB to be directly translated into a neutral 3-D solid geometry format for import into other CAE programs.
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10

Trushin, Oleg S. "Competing mechanisms of strain relaxation in Ge/Si(001) heteroepitaxy." In International Conference on Micro- and Nano-Electronics 2021, edited by Konstantin V. Rudenko and Vladimir F. Lukichev. SPIE, 2022. http://dx.doi.org/10.1117/12.2619657.

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Звіти організацій з теми "Strain mechanisms"

1

Hsiung, Luke L. Deformation Mechanisms in Body-Centered Cubic Metals at High Pressures and Strain Rates. Office of Scientific and Technical Information (OSTI), October 2018. http://dx.doi.org/10.2172/1481058.

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Li, Bin, Logan Shannahan, Evan Ma, Kaliatt T. Ramesh, Suveen Mathaudhu, Robert J. Dowding, and James W. McCauley. Deformation Mechanisms and High Strain Rate Properties of Magnesium (Mg) and Mg Alloys. Fort Belvoir, VA: Defense Technical Information Center, August 2012. http://dx.doi.org/10.21236/ada568946.

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Hirth, J. P., M. Rhee, H. M. Zhib, and T. D. de la Rubia. 3D dislocation dynamics: stress-strain behavior and hardening mechanisms in FCC and BCC metals. Office of Scientific and Technical Information (OSTI), February 1999. http://dx.doi.org/10.2172/12206.

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Guros, Frankie. Emotion Regulation and Strain in Corrections Officers: Examining the Role of Recovery Experiences and Coping Mechanisms. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.1121.

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5

Wang, Yu U. SISGR -- Domain Microstructures and Mechanisms for Large, Reversible and Anhysteretic Strain Behaviors in Phase Transforming Ferroelectric Materials. Office of Scientific and Technical Information (OSTI), December 2013. http://dx.doi.org/10.2172/1111107.

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6

Morrison, Mark, and Joshuah Miron. Molecular-Based Analysis of Cellulose Binding Proteins Involved with Adherence to Cellulose by Ruminococcus albus. United States Department of Agriculture, November 2000. http://dx.doi.org/10.32747/2000.7695844.bard.

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At the beginning of this project, it was clear that R. albus adhered tightly to cellulose and its efficient degradation of this polysaccharide was dependent on micromolar concentrations of phenylacetic acid (PAA) and phenylpropionic acid (PPA). The objectives for our research were: i) to identify how many different kinds of cellulose binding proteins are produced by Ruminococcus albus; ii) to isolate and clone the genes encoding some of these proteins from the same bacterium; iii) to determine where these various proteins were located and; iv) quantify the relative importance of these proteins in affecting the rate and extent to which the bacterium becomes attached to cellulose. BARD support has facilitated a number of breakthroughs relevant to our fundamental understanding of the adhesion process. First, R. albus possesses multiple mechanisms for adhesion to cellulose. The P.I.'s laboratory has discovered a novel cellulose-binding protein (CbpC) that belongs to the Pil-protein family, and in particular, the type 4 fimbrial proteins. We have also obtained genetic and biochemical evidence demonstrating that, in addition to CbpC-mediated adhesion, R. albus also produces a cellulosome-like complex for adhesion. These breakthroughs resulted from the isolation (in Israel and the US) of spontaneously arising mutants of R. albus strains SY3 and 8, which were completely or partially defective in adhesion to cellulose, respectively. While the SY3 mutant strain was incapable of growth with cellulose as the sole carbon source, the strain 8 mutants showed varying abilities to degrade and grow with cellulose. Biochemical and gene cloning experiments have been used in Israel and the US, respectively, to identify what are believed to be key components of a cellulosome. This combination of cellulose adhesion mechanisms has not been identified previously in any bacterium. Second, differential display, reverse transcription polymerase chain reaction (DD RT-PCR) has been developed for use with R. albus. A major limitation to cellulose research has been the intractability of cellulolytic bacteria to genetic manipulation by techniques such as transposon mutagenesis and gene displacement. The P.I.'s successfully developed DD RT- PCR, which expanded the scope of our research beyond the original objectives of the project, and a subset of the transcripts conditionally expressed in response to PAA and PPA have been identified and characterized. Third, proteins immunochemically related to the CbpC protein of R. albus 8 are present in other R. albus strains and F. intestinalis, Western immunoblots have been used to examine additional strains of R. albus, as well as other cellulolytic bacteria of ruminant origin, for production of proteins immunochemically related to the CbpC protein. The results of these experiments showed that R. albus strains SY3, 7 and B199 all possess a protein of ~25 kDa which cross-reacts with polyclonal anti-CbpC antiserum. Several strains of Butyrivibrio fibrisolvens, Ruminococcus flavefaciens strains C- 94 and FD-1, and Fibrobacter succinogenes S85 produced no proteins that cross-react with the same antiserum. Surprisingly though, F. intestinalis strain DR7 does possess a protein(s) of relatively large molecular mass (~200 kDa) that was strongly cross-reactive with the anti- CbpC antiserum. Scientifically, our studies have helped expand the scope of our fundamental understanding of adhesion mechanisms in cellulose-degrading bacteria, and validated the use of RNA-based techniques to examine physiological responses in bacteria that are nor amenable to genetic manipulations. Because efficient fiber hydrolysis by many anaerobic bacteria requires both tight adhesion to substrate and a stable cellulosome, we believe our findings are also the first step in providing the resources needed to achieve our long-term goal of increasing fiber digestibility in animals.
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Weinberg, Zwi G., Richard E. Muck, Nathan Gollop, Gilad Ashbell, Paul J. Weimer, and Limin Kung, Jr. effect of lactic acid bacteria silage inoculants on the ruminal ecosystem, fiber digestibility and animal performance. United States Department of Agriculture, September 2003. http://dx.doi.org/10.32747/2003.7587222.bard.

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The overall objective of the whole research was to elucidate the mechanisms by which LAB silage inoculants enhance ruminant performance. The results generated will permit the development of better silage inoculants that maximize both silage preservation and animal performance. For this one-year BARD feasibility study, the objectives were to: 1. determine whether lactic acid bacteria (LAB) used in inoculants for silage can survive in rumen fluid (RF) 2.select the inoculants that survived best, and 3. test whether LAB silage inoculants produce bacteriocins-like substances. The most promising strains will be used in the next steps of the research. Silage inoculants containing LAB are used in order to improve forage preservation efficiency. In addition, silage inoculants enhance animal performance in many cases. This includes improvements in feed intake, liveweight gain and milk production in 25-40% of studies reviewed. The cause for the improvement in animal performance is not clear but appears to be other than direct effect of LAB inoculants on silage fermentation. Results from various studies suggest a possible probiotic effect. Our hypothesis is that specific LAB strains interact with rumen microorganisms which results in enhanced rumen functionality and animal performance. The first step of the research is to determine whether LAB of silage inoculants survive in RF. Silage inoculants (12 in the U.S. and 10 in Israel) were added to clarified and strained RF. Inoculation rate was 10 ⁶ (clarified RF), 10⁷ (strained RF) (in the U.S.) and 10⁷, 10⁸ CFU ml⁻¹ in Israel (strained RF). The inoculated RF was incubated for 72 and 96 h at 39°C, with and without 5 g 1⁻¹ glucose. Changes in pH, LAB numbers and fermentation products were monitored throughout the incubation period. The results indicated that LAB silage inoculants can survive in RF. The inoculants with the highest counts after 72 h incubation in rumen fluid were Lactobacillus plantarum MTD1 and a L. plantarum/P. cerevisiae mixture (USA) and Enterococcus faecium strains and Lactobacillus buchneri (Israel). Incubation of rumen fluid with silage LAB inoculants resulted in higher pH values in most cases as compared with that of un-inoculated controls. The magnitude of the effect varied among inoculants and typically was enhanced with the inoculants that survived best. This might suggest the mode of action of LAB silage inoculants in the rumen as higher pH enhances fibrolytic microorganisms in the rumen. Volatile fatty acid (VFA) concentrations in the inoculated RF tended to be lower than in the control RF after incubation. However, L. plalltarull1 MTDI resulted in the highest concentrations of VFA in the RF relative to other inoculants. The implication of this result is not as yet clear. In previous research by others, feeding silages which were inoculated with this strain consistently enhanced animal performance. These finding were recently published in Weinberg et.al.. (2003), J. of Applied Microbiology 94:1066-1071 and in Weinberg et al.. (2003), Applied Biochemistry and Biotechnology (accepted). In addition, some strains in our studies have shown bacteriocins like activity. These included Pediococcus pentosaceus, Enterococcus faecium and Lactobacillus plantarum Mill 1. These results will enable us to continue the research with the LAB strains that survived best in the rumen fluid and have the highest potential to affect the rumen environment.
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Moser, Robert, Preet Singh, Lawrence Kahn, Kimberly Kurtis, David González Niño, and Zackery McClelland. Crevice corrosion and environmentally assisted cracking of high-strength duplex stainless steels in simulated concrete pore solutions. Engineer Research and Development Center (U.S.), August 2021. http://dx.doi.org/10.21079/11681/41620.

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This paper presents a study of crevice corrosion and environmentally assisted cracking (EAC) mechanisms in UNS S32205 and S32304 which were cold drawn to tensile strengths of approximately 1300 MPa. The study utilized a combination of electrochemical methods and slow strain rate testing to evaluate EAC susceptibility. UNS S32205 was not susceptible to crevice corrosion in stranded geometries at Cl⁻ concentrations up to 1.0 M in alkaline and carbonated simulated concrete pore solutions. UNS S32304 did exhibit a reduction in corrosion resistance when tested in a stranded geometry. UNS S32205 and S32304 were not susceptible to stress corrosion cracking at Cl⁻ concentrations up to 0.5 M in alkaline and carbonated solutions but were susceptible to hydrogen embrittlement with cathodic overprotection.
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Sionov, Edward, Nancy Keller, and Shiri Barad-Kotler. Mechanisms governing the global regulation of mycotoxin production and pathogenicity by Penicillium expansum in postharvest fruits. United States Department of Agriculture, January 2017. http://dx.doi.org/10.32747/2017.7604292.bard.

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The original objectives of the study, as defined in the approved proposal, are: To characterize the relationship of CreA and LaeA in regulation of P T production To understand how PacC modulates P. expansumpathogenicity on apples To examine if other secondary metabolites are involved in virulence or P. expansumfitness To identify the signaling pathways leading to PAT synthesis Penicilliumexpansum, the causal agent of blue mould rot, is a critical health concern because of the production of the mycotoxinpatulin (PAT) in colonized apple fruit tissue. Although PAT is produced by many Penicilliumspecies, the factors activating its biosynthesis were not clear. This research focused on host and fungal mechanisms of activation of LaeA (the global regulator of secondary metabolism), PacC (the global pH modulator) and CreA (the global carbon catabolite regulator) on PAT synthesis with intention to establish P. expansumas the model system for understanding mycotoxin synthesis in fruits. The overall goal of this proposal is to identify critical host and pathogen factors that mechanistically modulate P. expansumgenes and pathways to control activation of PAT production and virulence in host. Several fungal factors have been correlated with disease development in apples, including the production of PAT, acidification of apple tissue by the fungus, sugar content and the global regulator of secondary metabolism and development, LaeA. An increase in sucrose molarity in the culture medium from 15 to 175 mM negatively regulated laeAexpression and PAT accumulation, but, conversely, increased creAexpression, leading to the hypothesis that CreA could be involved in P. expansumPAT biosynthesis and virulence, possibly through the negative regulation of LaeA. We found evidence for CreAtranscriptional regulation of laeA, but this was not correlated with PAT production either in vitro or in vivo, thus suggesting that CreA regulation of PAT is independent of LaeA. Our finding that sucrose, a key ingredient of apple fruit, regulates PAT synthesis, probably through suppression of laeAexpression, suggests a potential interaction between CreA and LaeA, which may offer control therapies for future study. We have also identified that in addition to PAT gene cluster, CreA regulates other secondary metabolite clusters, including citrinin, andrastin, roquefortine and communesins, during pathogenesis or during normal fungal growth. Following creation of P. expansumpacCknockout strain, we investigated the involvement of the global pH regulator PacC in fungal pathogenicity. We demonstrated that disruption of the pH signaling transcription factor PacC significantly decreased the virulence of P. expansumon deciduous fruits. This phenotype is associated with an impairment in fungal growth, decreased accumulation of gluconic acid and reduced synthesis of pectolytic enzymes. We showed that glucose oxidase- encoding gene, which is essential for gluconic acid production and acidification during fruit colonization, was significantly down regulated in the ΔPepacCmutant, suggesting that gox is PacC- responsive gene. We have provided evidence that deletion of goxgene in P. expansumled to a reduction in virulence toward apple fruits, further indicating that GOX is a virulence factor of P. expansum, and its expression is regulated by PacC. It is also clear from the present data that PacC in P. expansumis a key factor for the biosynthesis of secondary metabolites, such as PAT. On the basis of RNA-sequencing (RNA-seq) analysis and physiological experimentation, the P. expansumΔlaeA, ΔcreAand ΔpacCmutants were unable to successfully colonize apples for a multitude of potential mechanisms including, on the pathogen side, a decreased ability to produce proteolytic enzymes and to acidify the environment and impaired carbon/nitrogen metabolism and, on the host side, an increase in the oxidative defence pathways. Our study defines these global regulatory factors and their downstream signalling pathways as promising targets for the development of strategies to fight against this post-harvest pathogen.
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Regueiro, Richard A. Nonlinear Micromorphic Continuum Mechanics and Finite Strain Elastoplasticity. Fort Belvoir, VA: Defense Technical Information Center, November 2010. http://dx.doi.org/10.21236/ada542966.

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