Letteratura scientifica selezionata sul tema "Constitutive system"
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Articoli di riviste sul tema "Constitutive system"
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García-Calderón, Clara B., Meritxell García-Quintanilla, Josep Casadesús e Francisco Ramos-Morales. "Virulence attenuation in Salmonella enterica rcsC mutants with constitutive activation of the Rcs system". Microbiology 151, n. 2 (1 febbraio 2005): 579–88. http://dx.doi.org/10.1099/mic.0.27520-0.
Testo completoAbstract (sommario):
Mutations in rcsC that result in constitutive colanic acid capsule synthesis were obtained in Salmonella enterica serovar Typhimurium. Most rcsC alleles were dominant; however, recessive rcsC alleles were also found, in agreement with the postulated double role (positive and negative) of RcsC on the activation of the RcsB/C phosphorelay system. Salmonella rcsC mutants with constitutive activation of the Rcs system are severely attenuated for virulence in BALB/c mice and their degree of attenuation correlates with the level of Rcs activation. Partial relief of attenuation by a gmm mutation indicates that capsule overproduction is one of the factors leading to avirulence in constitutively activated rcsC mutants.
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Adan, Roger A. H. "Constitutive Receptor Activity series Endogenous inverse agonists and constitutive receptor activity in the melanocortin system". Trends in Pharmacological Sciences 27, n. 4 (aprile 2006): 183–86. http://dx.doi.org/10.1016/j.tips.2006.02.002.
Testo completo
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Aerts, Dirk, Tom Verhaeghe, Marjan De Mey, Tom Desmet e Wim Soetaert. "A constitutive expression system for high-throughput screening". Engineering in Life Sciences 11, n. 1 (25 ottobre 2010): 10–19. http://dx.doi.org/10.1002/elsc.201000065.
Testo completo
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Hazan-Halevy, Inbal, David Harris, Zhiming Liu, Jie Liu, Ping Li, Xiaomin Chen, Sreejesh Shanker, Alessandra Ferrajoli, Michael J. Keating e Zeev Estrov. "STAT3 is constitutively phosphorylated on serine 727 residues, binds DNA, and activates transcription in CLL cells". Blood 115, n. 14 (8 aprile 2010): 2852–63. http://dx.doi.org/10.1182/blood-2009-10-230060.
Testo completoAbstract (sommario):
Abstract Chronic lymphocytic leukemia (CLL) is the most common leukemia in the Western hemisphere, but its pathogenesis is still poorly understood. Constitutive tyrosine phosphorylation (p) of signal transducer and activator of transcription (STAT) 3 occurs in several solid tumors and hematologic malignancies. In CLL, however, STAT3 is constitutively phosphorylated on serine 727, not tyrosine 705, residues. Because the biologic significance of serine pSTAT3 in CLL is not known, we studied peripheral blood cells of 106 patients with CLL and found that, although tyrosine pSTAT3 was inducible, serine pSTAT3 was constitutive in all patients studied, regardless of blood count, disease stage, or treatment status. In addition, we demonstrated that constitutive serine pSTAT3 translocates to the nucleus by the karyopherin-β nucleocytoplasmic system and binds DNA. Dephosphorylation of inducible tyrosine pSTAT3 did not affect STAT3-DNA binding, suggesting that constitutive serine pSTAT3 binds DNA. Furthermore, infection of CLL cells with lentiviral STAT3-small hairpin RNA reduced the expression of several STAT3-regulated survival and proliferation genes and induced apoptosis, suggesting that constitutive serine pSTAT3 initiates transcription in CLL cells. Taken together, our data suggest that constitutive phosphorylation of STAT3 on serine 727 residues is a hallmark of CLL and that STAT3 be considered a therapeutic target in this disease.
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Kirkby, Nicholas S., Melissa V. Chan, Anne K. Zaiss, Eliana Garcia-Vaz, Jing Jiao, Lisa M. Berglund, Elena F. Verdu et al. "Systematic study of constitutive cyclooxygenase-2 expression: Role of NF-κB and NFAT transcriptional pathways". Proceedings of the National Academy of Sciences 113, n. 2 (28 dicembre 2015): 434–39. http://dx.doi.org/10.1073/pnas.1517642113.
Testo completoAbstract (sommario):
Cyclooxygenase-2 (COX-2) is an inducible enzyme that drives inflammation and is the therapeutic target for widely used nonsteroidal antiinflammatory drugs (NSAIDs). However, COX-2 is also constitutively expressed, in the absence of overt inflammation, with a specific tissue distribution that includes the kidney, gastrointestinal tract, brain, and thymus. Constitutive COX-2 expression is therapeutically important because NSAIDs cause cardiovascular and renal side effects in otherwise healthy individuals. These side effects are now of major concern globally. However, the pathways driving constitutive COX-2 expression remain poorly understood. Here we show that in the kidney and other sites, constitutive COX-2 expression is a sterile response, independent of commensal microorganisms and not associated with activity of the inflammatory transcription factor NF-κB. Instead, COX-2 expression in the kidney but not other regions colocalized with nuclear factor of activated T cells (NFAT) transcription factor activity and was sensitive to inhibition of calcineurin-dependent NFAT activation. However, calcineurin/NFAT regulation did not contribute to constitutive expression elsewhere or to inflammatory COX-2 induction at any site. These data address the mechanisms driving constitutive COX-2 and suggest that by targeting transcription it may be possible to develop antiinflammatory therapies that spare the constitutive expression necessary for normal homeostatic functions, including those important to the cardiovascular-renal system.
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Hamilton, Ruth, Mike Siva-Jothy e Mike Boots. "Two arms are better than one: parasite variation leads to combined inducible and constitutive innate immune responses". Proceedings of the Royal Society B: Biological Sciences 275, n. 1637 (29 gennaio 2008): 937–45. http://dx.doi.org/10.1098/rspb.2007.1574.
Testo completoAbstract (sommario):
Parasites represent a major threat to all organisms which has led to the evolution of an array of complex and effective defence mechanisms. Common to both vertebrates and invertebrates are innate immune mechanisms that can be either constitutively expressed or induced on exposure to infection. In nature, we find that a combination of both induced and constitutive responses are employed by vertebrates, invertebrates and, to an extent, plants when they are exposed to a parasite. Here we use a simple within-host model motivated by the insect immune system, consisting of both constitutive and induced responses, to address the question of why both types of response are maintained so ubiquitously. Generally, induced responses are thought to be advantageous because they are only used when required but are too costly to maintain constantly, while constitutive responses are advantageous because they are always ready to act. However, using a simple cost function but with no a priori assumptions about relative costs, we show that variability in parasite growth rates selects for a strategy that combines both constitutive and induced defences. Differential costs are therefore not necessary to explain the adoption of both forms of defence. Clearly, hosts are likely to be challenged by variable parasites in nature and this is sufficient to explain why it is optimal to deploy both arms of the innate immune system.
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Singer, John T., Ryan T. Phennicie, Matthew J. Sullivan, Laura A. Porter, Valerie J. Shaffer e Carol H. Kim. "Broad-Host-Range Plasmids for Red Fluorescent Protein Labeling of Gram-Negative Bacteria for Use in the Zebrafish Model System". Applied and Environmental Microbiology 76, n. 11 (2 aprile 2010): 3467–74. http://dx.doi.org/10.1128/aem.01679-09.
Testo completoAbstract (sommario):
ABSTRACT To observe real-time interactions between green fluorescent protein-labeled immune cells and invading bacteria in the zebrafish (Danio rerio), a series of plasmids was constructed for the red fluorescent protein (RFP) labeling of a variety of fish and human pathogens. The aim of this study was to create a collection of plasmids that would express RFP pigments both constitutively and under tac promoter regulation and that would be nontoxic and broadly transmissible to a variety of Gram-negative bacteria. DNA fragments encoding the RFP dimeric (d), monomeric (m), and tandem dimeric (td) derivatives d-Tomato, td-Tomato, m-Orange, and m-Cherry were cloned into the IncQ-based vector pMMB66EH in Escherichia coli. Plasmids were mobilized into recipient strains by conjugal mating. Pigment production was inducible in Escherichia coli, Pseudomonas aeruginosa, Edwardsiella tarda, and Vibrio (Listonella) anguillarum strains by isopropyl-β-d-thiogalactopyranoside (IPTG) treatment. A spontaneous mutant exconjugant of P. aeruginosa PA14 was isolated that expressed td-Tomato constitutively. Complementation analysis revealed that the constitutive phenotype likely was due to a mutation in lacI q carried on pMMB66EH. DNA sequence analysis confirmed the presence of five transitions, four transversions, and a 2-bp addition within a 14-bp region of lacI. Vector DNA was purified from this constitutive mutant, and structural DNA sequences for RFP pigments were cloned into the constitutive vector. Exconjugants of P. aeruginosa, E. tarda, and V. anguillarum expressed all pigments in an IPTG-independent fashion. Results from zebrafish infectivity studies indicate that RFP-labeled pathogens will be useful for the study of real-time interactions between host cells of the innate immune system and the infecting pathogen.
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Cheng, Tao. "Numerical Simulation for the Deformation of Composite Wall Insulation System". Advanced Materials Research 374-377 (ottobre 2011): 187–90. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.187.
Testo completoAbstract (sommario):
The nonlinear constitutive relations of clay are investigated with different initial stress conditions. Two series of triaxial compression tests are performed, respectively after consolidation and isotropic consolidation. On the basis of the framework of ~ model, a uniform nonlinear constitutive model is proposed by fitting of the test data. With the average slope of the unloading-reloading curve selected as the unloading modulus, the unloading function is constructed as the loading-unloading criterion. Moreover, a comparison of the experimental stress-strain curves with the predicted results by the constitutive model is made. It is shown that the model prediction is reasonable, which can reflect the stress-strain behavior of the soil under the consolidation and isotropic consolidation conditions.
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Bednář, Miloš. "The constitutive values of fair play". AUC KINANTHROPOLOGICA 59, n. 2 (23 gennaio 2024): 79–92. http://dx.doi.org/10.14712/23366052.2023.5.
Testo completoAbstract (sommario):
Fair play as a phenomenon of sporting life is present even if only in the form of small acts or gestures in most competitions; its absence is present in cases of foul play. The daily press comments its presence or absence every day in, and not only in the sports sections. Both the public and experts discuss acts from so called grey zone (forms of gamesmanship). Deciding unequivocally on the moral quality of a diverse range of actions, attitudes or statements requires clarity about the values underpinning fair play. Our aim is therefore to find the constitutive values of fair play by examining a set of values from the field of sport, rel¬evant offerings from fundamental ethics, using Abraham Maslow’s meta-value system and selection from the fundamental values of fair play considered so far. Organizing the selected values into a meaningful system is the final aim. We used a hermeneutic method to interpret the role of values within fair play. We identify five values and five meta-values as constitutive of fair play, the meta-values of goodness, truth, and transcendence as the basis of the entire system. We identify character (of athletes) and ethos (of sports communities) as both initiators of activities within the system and recipients of benefits.
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Kasperavičius, Algis. "Constitutive Parliament and its speakers". Lietuvos istorijos studijos 12 (29 dicembre 2003): 36–46. http://dx.doi.org/10.15388/lis.2003.37174.
Testo completoAbstract (sommario):
On April of 1920, elected Constitutive Parliament term continued till the 6th of October 1922. It worked strenuously; there took place 257 ordinary meetings, which continued for some hours every day. They often ended in the next morning. The most important task of the Constitutive Parliament was to prepare a permanent Constitution of the Lithuanian Republic, but it performed other rules' publishing functions too. It performed the control of executive government institutions of all levels. The education of parliament members was much better than the middle education of Lithuanian citizens, but most of them didn't have university education. However, it wasn't a big imperfection of the just born parliamentary system of Lithuania. A diploma or an academic degree isn't identical to the broad mind and the knowledge necessary for political leaders. It can be acquired in the way of self-education too. Oratorical skills are very important as well. In opposition to other parliaments of the West, there weren't many lawyers in the Lithuanian Constitutive Parliament, but there were oratory skills characteristic of other professions' representatives, who sometimes didn't have both the university degree and secondary education. For example, leaders of social democrats like K. Bielinis and J. Plečkaitis. Next to them, the most eminent orators were social democrats: an engineer S. Kairys, a scientist-chemist V. Čepinskis, a leader of populists M. Sleževičius, and a Christian democrat priest M. Krupavičius. In the constitutive parliament, the Right and the Left differed from each other not only in the matter of social reforms, first of all agrarian reform, but also in their standpoint on Catholic religion and the church's place in the state. Disagreements reached their culmination in 1922 during the discussion about the final wording of the constitution. The offers of social democrats and populists were rejected because the majority of votes were held by Christian democrats. In addition, the Right used not only objective arguments but also demagogy. The Right abstained from voting for the Constitution. It was accepted by Christian democrats and by a few executives of national minorities. The anticlericalism of the Left was one of the causes that influenced the downfall of parliamentary democracy in Lithuania as a result of the revolution in December 1926. Discussions in the Constitutive Parliament showed that its members seriously looked at the work of Constitution preparation, though they were not always able to find compromises. They weren't afraid to express their opinion, and they didn't tremble because of the reaction in Warsaw, Paris, Moscow, or London.
Tesi sul tema "Constitutive system"
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Maclennan, Richard Alexander. "Activation of constitutive androstane receptor (CAR) in primary human hepatocytes". Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/33726/.
Testo completoAbstract (sommario):
Human populations are at risk of exposure to constitutive androstane receptor (CAR) activators present in a range of substances, including pharmaceuticals, plasticizers and crop protection agents. What exposure to CAR activators means for human health is uncertain. Activation of CAR in rodents is associated with liver hyperplasia, increased proliferation and eventual hepatocarcinoma; however the effect in human hepatic cells is unclear. There are two methods by which a compound can achieve activation of CAR; directly or indirectly via cellular signalling pathways. Phenobarbital is a prototypical activator of CAR and does so in an indirect manner via suppression of epidermal growth factor receptor (EGFR) signalling. Direct activation of CAR in rodents also causes hepatocellular carcinoma but the human outcome is less clear. We have carried out microarray and miRNA analysis of CITCO (a potent and selective hCAR ligand) treated primary human hepatocytes. To mitigate the well documented effect of primary hepatocyte dedifferentiation primary hepatocytes were cultured in dynamic three dimensional culture in vitro. Gene expression changes indicate that direct activation of hCAR causes the promotion of a pro-proliferative and anti-apoptotic phenotype. The miRNA expression profile is crucially different to rodent data that is currently published. Despite the pro-proliferative phenotype shown there is no evidence that primary human hepatocytes proliferate in response to direct activation of CAR by CITCO. This leaves the possibility that a proliferative response may be observed in vivo or that the changes in gene expression are solely a human physiological adaptation to direct hCAR activation by CITCO and no proliferation would occur. The effect on human health and liver toxicity is unclear but this body of work has provided data that may be used to further understand the mechanistic effects of direct hCAR activation in human hepatocytes. A more complete understanding of this will help to inform the toxic potential of direct hCAR activation in vivo.
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Wu, Yanzhang. "Sensing Nonlinear Viscoelastic Constitutive Parameters with a Geometrically Nonlinear Beam: Modeling and Simulation". Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40910.
Testo completoAbstract (sommario):
In this thesis, we present a sensor model comprised of a geometrically nonlinear beam coupled with a nonlinear viscoelastic Pasternak foundation via a distributed system of compliant elements. The governing equations of the system are obtained. By posing an inverse problem, the model is used to simulate the estimation of coupled substrates' material (constitutive) parameters. In the inverse problem, beam deformations are considered as measured parameters, and therefore an eventual hardware implementation would require measurements of these quantities. Different case studies are simulated to assess the robustness and applicability of this sensor model.
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Hai, Lan. "EFFECT OF CONSTITUTIVELY ACTIVATED LUTEINIZING HORMONE RECEPTOR ON THE MOUSE REPRODUCTIVE SYSTEM". OpenSIUC, 2016. https://opensiuc.lib.siu.edu/dissertations/1208.
Testo completoAbstract (sommario):
AN ABSTRACT OF THE DISSERTATION OF LAN HAI, for the Doctor of Philosophy degree in Molecular Cellular and Systemic Physiology, presented on 11th December, 2015 at Southern Illinois University Carbondale. TITLE: EFFECT OF CONSTITUTIVELY ACTIVATED LUTEINIZING HORMONE RECEPTOR ON THE MOUSE REPRODUCTIVE SYSTEM MAJOR PROFESSOR: Dr. Prema Narayan The luteinizing hormone/chorionic gonadotropin receptor (LHCGR) is crucial for fertility, and genetic mutations in LHCGR cause adverse effects in reproductive development. Among the activating mutations identified in LHCGR, replacement of aspartic acid 578 by glycine (D578G) is the most common inherited mutation. Boys with this mutation undergo puberty by 2-4 years, caused by elevated testosterone in the context of prepubertal luteinizing hormone levels and present with Leydig cell hyperplasia. Clinically, these symptoms are associated with familial male-limited precocious puberty (FMPP). Our lab has published a mouse model for FMPP (KiLHRD582G) with D582G mutation equivalent to D578G in human LHCGR. We have previously demonstrated that KiLHRD582G male mice exhibited precocious puberty, Leydig cell hyperplasia and elevated testosterone and was a good model for FMPP. However, unlike women with the D578G mutation who show no abnormal phenotype, our studies revealed that female KiLHRD582G mice were infertile. KiLHRD582G female mice exhibit precocious puberty and irregular estrous cyclicity. A temporal study from 2-24 weeks of age indicated elevated steroid levels and upregulation of steroidogenic acute regulatory protein as well as several steroidogenic enzyme genes. Ovaries of KiLHRD582G mice exhibited significant pathology with the development of large hemorrhagic cysts as early as 3 weeks of age, extensive stromal cell hyperplasia with luteinization, numerous atretic follicles and granulosa cell tumors. Anovulation could not be rescued by exogenous gonadotropins. The body weights of the KiLHRD582G mice was higher that wild type counterparts, but there were no differences in the body fat composition. Hyperandrogenism and polycystic ovary phenotype was not accompanied by impaired glucose tolerance. Blocking the androgen action and estrogen synthesis indicated that reproductive phenotype was primarily due to excess estradiol. These studies demonstrate that activating LHCGR mutations do not produce the same phenotype in humans and mice and clearly illustrates species differences in the expression and regulation of LHCGR in the ovary. As we use male KiLHRD582G mice as breeders, we observed that the KiLHRD582G mice became progressive infertile, and only 8% of KiLHRD582G were fertile at 6 months of age despite normal sperm production. The infertile KiLHRD582G males were not able to form copulatory plugs in WT females, and mating studies suggested that the KiLHRD582G males were not capable of mating and/or ejaculating. Sexual behavioral testing revealed that the infertile KiLHRD582G males were capable of mounting the receptive WT females but were unable to achieve ejaculation indicating a problem with erectile and/or ejaculatory function. To address the reason for the ejaculatory dysfunction, we performed histopathological analysis of the accessory glands and penis. Hematoxylin and eosin staining showed that the normal columnar epithelium was replaced by pseudostratified columnar epithelium in the ampulla and several aggregates of chondrocyte metaplasia were apparent in the penile body of KiLHRD582G male mice. A temporal study indicated the histopathological changes in ampulla and penile body initiated at 7-8 and 12 weeks of age, respectively. Immunohistochemistry indicated that the chondrocytes stained positive for collagen type II, SOX9 and androgen receptor in the nucleus and for LHCGR in the cytoplasm. Penile fibrosis is a major cause of erectile dysfunction and is characterized by an increased collagen/smooth muscle ratio. However, our Image J analysis, hydroxyproline assay and western blot showed that KiLHRD582G penile body exhibited reduced levels of smooth muscle actin but similar total collagen content compared to WT mice. Thus, penile fibrosis was not responsible for the progressive infertility of adult KiLHRD582G mice. We also observed Leydig cell adenoma and disruption of spermatogenesis at 1 year of age. Our results suggest FMPP patients may be susceptible to infertility and testicular tumors later in their life and a follow-up study of FMPP patients is recommended.
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De, Vittorio Giancarlo. "Crack measurements in structural concrete with D.I.C. system and validation of a tensile constitutive law". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amslaurea.unibo.it/2048/.
Testo completoAbstract (sommario):
Compared with other mature engineering disciplines, fracture mechanics of concrete is still a developing field and very important for structures like bridges subject to dynamic loading. An historical point of view of what done in the field is provided and then the project is presented. The project presents an application of the Digital Image Correlation (DIC) technique for the detection of cracks at the surface of concrete prisms (500mmx100mmx100mm) subject to flexural loading conditions (Four Point Bending test). The technique provide displacement measurements of the region of interest and from this displacement field information about crack mouth opening (CMOD) are obtained and related to the applied load. The evolution of the fracture process is shown through graphs and graphical maps of the displacement at some step of the loading process. The study shows that it is possible with the DIC system to detect the appearance and evolution of cracks, even before the cracks become visually detectable.
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Manzerra, Pasquale. "Expression of constitutive hsc70 and stress-inducible hsp70 mRNA and protein in the rabbit central nervous system". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0009/NQ28007.pdf.
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Furlotte, Wesley Joseph. "Unruly Extimacy: The Problem of Nature in Hegel's Final System". Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31770.
Testo completoAbstract (sommario):
Concentrating on G.W.F. Hegel’s controversial Naturphilosophie (1830), Part I ventures the following thesis: Hegelian nature is characterized by a “constitutive lack.” Insofar as the natural register lacks the precision and necessity immanent within the dialectical developments of conceptual thought it is capable of radical novelty—the unexpected. This is important: it offers a sense of how the natural register is open to thought and yet, simultaneously, a source of that which has the perpetual possibility of undermining conceptual distinctions and anticipations. The remainder of the project systematically maps what such a conception of nature must mean in terms of Hegel’s concept of spirit (Geist). Consequently, Part II analyzes Hegel’s bizarre account of psychopathology. The central thesis in this context claims that what Hegel’s speculative analysis of ‘madness’ shows us are the ways in which subjectivity might be dominated by its material-instinctual dimension as it unfolds within the unconscious depths of concrete subjectivity. Subjectivity retains the perpetual possibility of regression insofar as it reverts to being materially (maternally) determined strictly by way of externality. Questioning the presupposition of nature’s complete sublation, Part III focuses on Hegel’s political writings. Hegel’s analysis of criminality and punishment allows for the possibility of what we will call “surplus repressive punishment.” A surplus repressive punishment, a brute form of natural external pressure, would constitute spirit’s, i.e. freedom’s, “regressive de-actualization” at both the individual (subjective) and intersubjective (objective, communal) levels. Therefore, surplus repressive punishment, as an expression of spirit’s naturality, serves to undermine spirit’s objective actualization in its entirety. The problem of nature remains very much an active dimension of spirit’s concrete actualization at the socio-political level. The project offers a precise indication of how Hegel’s philosophy of spirit, i.e. his philosophy of freedom, is one intertwined with the problem instantiated by the matrices of nature. Sensitivity to this problem, that there is a problem here, and that Hegel’s system can be pursued to address it is one of the not always recognized merits of his thought. Simultaneously, Hegel’s system becomes surprisingly relevant for our contemporary world insofar as nature remains a problem for our living present.
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Vecchini, Françoise. "Étude de l'expression constitutive et inductible des enzymes de phase I et II dans les cellules épidermiques humaines : mécanisme de la régulation du cytochrome P4501A1". Nancy 1, 1994. http://www.theses.fr/1994NAN10450.
Testo completo
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Vecchini, Françoise. "Étude de l'expression constitutive et inductible des enzymes de phase I et II dans les cellules épidermiques humaines : mécanisme de la régulation du cytochrome P4501A1". Nancy 1, 1994. http://www.theses.fr/1994NAN12102.
Testo completo
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Taylor, Zeike Amos. "Patient-specific models of cartilaginous tissues based on laser scanning confocal arthroscopy". University of Western Australia. School of Mechanical Engineering, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0097.
Testo completoAbstract (sommario):
[Truncated abstract] An important field of research in orthopaedic biomechanics is the elucidation and mathematical modelling of the mechanical response of cartilaginous tissues. Such research has applications in the understanding of joint function and degenerative processes, as well as in surgical planning and simulation, and engineering of tissue replacements. In the case of surgical and tissue engineering applications especially, patient-specific mechanical properties are highly desirable. Unfortunately, obtaining such information would generally involve destructive mechanical testing of patient tissue, thus rendering the tissue functionally unusable. Development of a laser scanning confocal arthroscope (LSCA) within our School will soon allow non-invasive extraction of 3D microstructural images of cartilaginous tissues in vivo. It is also envisaged that, linked to a suitably formulated constitutive formulation, such information could allow estimation of tissue mechanical response without physical biopsy. This thesis describes the development of techniques to potentially allow non-invasive patient-specific estimation of tissue mechanical response based on confocal arthroscopy data. A microstructural constitutive model is developed which is capable of directly incorporating LSCA-derived patient-specific structural information. A fibre composite type homogenisation approach is used as the basis for the model. ... The result is a series of orientation tensors describing the 3D orientation of linear features in the image stack. The developed analysis techniques are used to estimate fibre volume fraction and orientation distribution for each of the meniscal specimens. The developed constitutive model and image-derived structural parameters are finally used to estimate the reaction force history of two meniscal cartilage specimens subjected to partially confined compression. The predictions are made on the basis of the specimens? individual structural condition as assessed by confocal microscopy and involve no tuning of material parameters. Although the model does not reproduce all features of the experimental curves, as an unfitted estimate of mechanical response the prediction is quite accurate. In light of the obtained results it is judged that more general non-invasive estimation of tissue mechanical properties is possible using the developed framework. The likely limitations and potential areas of improvement are discussed.
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Reis, Martina Costa 1986. "Constitutive modeling of electrochemical systems via the Müller-Liu entropy principle = Modelagem constitutiva de sistemas eletroquímicos através do princípio de entropia Müller-Liu". [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249906.
Testo completoAbstract (sommario):
Orientador: Adalberto Bono Maurizio Sacchi BassiTese (doutorado) - Universidade Estadual de Campinas, Instituto de Química
Made available in DSpace on 2018-08-25T02:48:09Z (GMT). No. of bitstreams: 1 Reis_MartinaCosta_D.pdf: 1200753 bytes, checksum: 9318dbbd02e3d4660c4a6806e68dad7d (MD5) Previous issue date: 2014
Resumo: Este trabalho descreve a termodinâmica de sistemas eletroquímicos. Explorando os princípios da teoria constitutiva, algumas hipóteses ad hoc e, em especial, o princípio de entropia Müller-Liu, modelos termo-eletroquímicos são propostos para soluções eletrolíticas e para as regiões de bulk e dupla camada de um sistema eletroquímico. A influência das interações íon-íon e íon-solvente sobre a dinâmica da mistura é considerada através da termodinâmica de contínuos polares e as equações de balanço são apropriadamente postuladas. Além disso, equações fenomenológicas são apresentadas para uma solução eletrolítica diluída e isotrópica e as condições para o equilíbrio termodinâmico local do bulk e da dupla camada são investigadas. Comparando-se as desigualdades residuais de entropia obtidas para cada região, foi demonstrado que alguns processos, tais como os fenômenos de difusão térmica, termoeletricidade e eletroforese, desenvolvem-se somente na dupla camada. Consequentemente, o estado de equilíbrio termodinâmico local na dupla camada requer condições termodinâmicas mais severas do que no bulk. Apesar das equações constitutivas serem as mais simples possíveis, os modelos constitutivos propostos para as regiões de dupla camada e bulk são fisicamente consistentes e mais abrangentes do que os modelos eletroquímicos usuais, visto que as equações e relações termodinâmicas obtidas não se limitam às condições limites e nem de equilíbrio. Portanto, a descrição termodinâmica mostrada neste trabalho pode estimular químicos e engenheiros químicos a usar a abordagem contínua no estudo da mobilidade iônica em meios bio e geológicos, fluxos de íons e de outras espécies químicas através de membranas e processos cujas transferências de calor e massa são intensificadas por campos eletromagnéticos
Abstract: This work concerns the thermodynamics of electrochemical systems. Exploiting the principles of constitutive theory, few expedient assumptions, and, in special, the Müller-Liu entropy principle, a thermo-electrochemical continuum model is proposed for electrolyte solutions as well as for the bulk and double layer regions of an electrochemical system. The influence of ion-ion and ion-solvent interactions on the mixture dynamics is taken into account through the thermodynamics of polar materials and balance laws for an electrochemical system are accordingly stated. In addition, phenomenological equations are schemed for a dilute and isotropic electrolyte solution, and the conditions for local thermodynamic equilibrium of bulk and double layer regions are investigated. Comparing the residual entropy inequalities obtained for each region of an electrochemical system, it is shown that some mechanisms develop only in the double layer, such as the thermal diffusion, thermoelectricity and electrophoresis phenomena. As a consequence, the local thermodynamic equilibrium state in the double layer requires stricter conditions than in the bulk. Although the constitutive equations are the simplest possible, the constitutive models proposed for the double layer and bulk regions are physically consistent and more comprehensive than the usual models since the emerging equations do not constrain themselves to equilibrium neither limiting conditions. Therefore, the thermodynamic description provided in this work may stimulate chemists and chemical engineers to take advantage of it to study the flow of ions and other chemical species across cell membranes, ionic mobility in bio and geological media, and processes whose heat and mass transfers are enhanced by electromagnetic fields
Doutorado
Físico-Química
Doutora em Ciências
Libri sul tema "Constitutive system"
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Manzerra, Pasquale. Expression of constitutive hsc70 and stress-inducible hsp70 mRNA and protein in the rabbit central nervous system. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1997.
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Haken, H. Die Selbststrukturierung der Materie: Synergetik in der unbelebten Welt. Braunschweig: Vieweg, 1991.
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Vermeule, Adrian. The system of the constitution. New York: Oxford University Press, 2011.
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Vermeule, Adrian. System effects and the constitution. Cambridge, MA: Harvard Law School, 2009.
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Vermeule, Adrian. System effects and the constitution. Cambridge, MA: Harvard Law School, 2009.
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Cogswell, John Marshall. Fix the system: Reform the Constitution. Buena Vista, CO: Campaign Constitution Press, 2012.
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1923-, Grover Verinder, a cura di. Political system and constitution of India. New Delhi: Deep & Deep Publications, 1997.
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M, Odegard Gregory, e Langley Research Center, a cura di. Constitutive modeling of nanotube-reinforced polymer composite systems. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 2001.
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R, Young William, e Canada. Library of Parliament. Political and Social Affairs Division., a cura di. Municipalities, the constitution, and the Canadian federal system. Ottawa: Research Branch, Library of Parliament, 1991.
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Canada. Library of Parliament. Research Branch. Municipalities, the constitution, and the Canadian federal system. Ottawa: Library of Parliament, 1991.
Cerca il testo completoCapitoli di libri sul tema "Constitutive system"
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van Dommelen, J. A. W., M. Hrapko e G. W. M. Peters. "Mechanical Properties of Brain Tissue: Characterisation and Constitutive Modelling". In Mechanosensitivity of the Nervous System, 249–79. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-1-4020-8716-5_12.
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Rouse, Robert V. "Is Ia Antigen Expression by Thymic Epithelial Cells Constitutive?" In Microenvironments in the Lymphoid System, 915–19. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4613-2463-8_110.
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Redon, A., M. Miroir, E. Robin, J. B. Le Cam e J. C. Fralin. "Aging of NBR: Application to O-rings used in the braking system of the French high-speed train". In Constitutive Models for Rubber XII, 420–26. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003310266-69.
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von Storch, Hans, Jin-Song von Storch e Peter Müller. "Noise in the Climate System — Ubiquitous, Constitutive and Concealing". In Mathematics Unlimited — 2001 and Beyond, 1179–94. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-56478-9_62.
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Huang, Chunyuan, e Robin D. Graham. "Efficient Mn uptake in barley is a constitutive system". In Plant Nutrition for Sustainable Food Production and Environment, 269–70. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-009-0047-9_75.
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Yamada, Hiroshi. "Inelastic Constitutive Models of Blood Vessels in Physiological Conditions". In Clinical Application of Computational Mechanics to the Cardiovascular System, 19–28. Tokyo: Springer Japan, 2000. http://dx.doi.org/10.1007/978-4-431-67921-9_2.
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Wang, Jizhe, Shouju Li, Juan Cui e Lintao Man. "Parameter Inversion of Constitutive Model of Soil Using Neural Networks". In Advances in Computer Science, Intelligent System and Environment, 417–20. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-23756-0_67.
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Duenas, Terrisa, Jennifer Schlitter, Naida Lacevic, Akhilesh Jha, Karen Chai, Fred Wudl, Lucas Westcott-Baker, Ajit Mal, Aaron Corder e Teng K. Ooi. "Ballistic Missile Defense System (BMDS) Solutions Using Remendable Polymers". In Time Dependent Constitutive Behavior and Fracture/Failure Processes, Volume 3, 267–73. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-9794-4_37.
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Zhao, Chenyang, Arash Alimardani Lavasan, Thomas Barciaga, Raoul Hölter, Maria Datcheva e Tom Schanz. "Constitutive Parameter Adjustment for Mechanized Tunneling with Reference to Sub-system Effects". In Numerical Methods and Applications, 217–25. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-15585-2_24.
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Tsukuni, S., T. Shiomi, M. Hatanaka, Y. Tanaka, Y. Suzuki e T. Hirose. "Simulation Analysis of Ground Liquefaction in a Soil-structures System of a Shaking Table Test". In Transient/Dynamic Analysis and Constitutive Laws for Engineering Materials, 365–72. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3655-3_40.
Testo completoAtti di convegni sul tema "Constitutive system"
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Odegard, G. M., T. L. Haut Donahue, D. A. Morrow e K. R. Kaufman. "Constitutive Modeling of Skeletal Muscle Tissue". In ASME 2007 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2007. http://dx.doi.org/10.1115/sbc2007-175848.
Testo completoAbstract (sommario):
The main functions of the human musculoskeletal system are to sustain loads and provide mobility. Bones and joints themselves cannot produce movement; skeletal muscles provide the ability to move. Knowledge of muscle forces during given activities can provide insight into muscle mechanics, muscle physiology, musculoskeletal mechanics, neurophysiology, and motor control. However, clinical examinations or instrumented strength testing only provides information regarding muscle groups. Musculoskeletal models are typically needed to calculate individual muscle forces.
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Simović, Darko, e Ivana Krstić-Mistridželović. "PROŠIRIVANjE TRADICIONALNE USTAVNE MATERIJE –SOCIJALNE I EKONOMSKE ODREDBE U VIDOVDANSKOM USTAVU". In 100 GODINA OD VIDOVDANSKOG USTAVA. Faculty of law, University of Kragujevac, 2021. http://dx.doi.org/10.46793/zbvu21.285s.
Testo completoAbstract (sommario):
The final establishment of a unified Yugoslavian state, as the fundamental reason behind the adoption of the Vidovdan Constitution, contributed to the overshadowing of all other characteristics of this act by the unified state system. Although it is one of the common conceptions that the Vidovdan Constitution had to a great extent copied the economic and social provisions of the Weimar Constitution, much less attention was given to the fact that the nature of this constitution, as the highest legal act, was somewhat modified. Comparatively, the Kingdom of Serbs, Croats and Slovenes was amongst the first to transform their constitution from a purely organizational-constitutive act by implementing elements of an economic and social charter as a future-ready program. The constitution is no longer only a constitutive act of a state, it simultaneously serves as an act that transforms the state from a political organization into a social and cultural community. In addition, although the Weimar Constitution was an exemplary model, the framers of the Vidovdan constitution were not plagiarizers, as they were original in many of their provisions. Distinctive constitutional provisions were the result of complex socio-political circumstances at the time that the framers of the constitution had to consider in order for the constitution to be adopted.
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Wang, Lili, e Hui Wang. "Mechanics Modeling and Inverse Analyses of Pulse Wave System From the View-Point of Traditional Chinese Medicine". In ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/omae2016-55106.
Testo completoAbstract (sommario):
Follow the holism concept of traditional Chinese medicine (TCM), the pulse wave system is considered as an entire system of life energy propagating within the blood in the form of wave. A corresponding mechanics model is established, showing that a pulse phenomenon includes both the blood flow and the energy wave propagating within the blood. The former is a visible matter-flow with lower velocity, while the latter is an invisible energy-flow with much higher velocity, corresponding respectively to the “blood” and the “Qi” in TCM. Moreover the method of inverse analysis in the wave propagation theory is generalized to deal with the pulse wave signals. Once anyone form of pulse wave, e.g. the pressure wave, is measured, the other forms of pulse wave such as the particle velocity wave, the specific volume wave and the internal energy wave can all be deduced, and finally the constitutive equation of the system can be determined. The propagating characters of pulse wave are mainly determined by the constitutive equation of the system, which may correspond to the “body constitution” in TCM. Some intrinsic relationship may exist between them and should be further investigated.
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Rahman, Syed M., Tasnim Hassan e S. Ranji Ranjithan. "Automated Parameter Determination of Advanced Constitutive Models". In ASME 2005 Pressure Vessels and Piping Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pvp2005-71634.
Testo completoAbstract (sommario):
Parameter determination of advanced cyclic plasticity models which are developed for simulation of cyclic stress-strain and ratcheting responses is complex. This is mainly because of the large number of model parameters which are interdependent and three or more experimental responses are used in parameter determination. Hence the manual trial and error approach becomes quite tedious and time consuming for determining a reasonable set of parameters. Moreover, manual parameter determination for an advanced plasticity model requires in-depth knowledge of the model and experience with its parameter determination. These are few of the primary reasons for advanced cyclic plasticity models not being widely used for analysis and design of fatigue critical structures. These problems could be overcome through developing an automated parameter optimization system using heuristic search technique (e.g. genetic algorithm). This paper discusses the development of such an automatic parameter determination scheme for improved Chaboche model developed by Bari and Hassan [4]. A new stepped GA optimization approach which is found to be more efficient over the conventional GA approach in terms of fitness quality and optimization time is presented.
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Michopoulos, John G., Athanasios Iliopoulos, John C. Hermanson, Adrian C. Orifici e Rodney S. Thomson. "Preliminary Validation of Composite Material Constitutive Characterization". In ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/detc2012-71082.
Testo completoAbstract (sommario):
This paper is describing the preliminary results of an effort to validate a methodology developed for composite material constitutive characterization. This methodology involves using massive amounts of data produced from multiaxially tested coupons via a 6-DoF robotic system called NRL66.3 developed at the Naval Research Laboratory. The testing is followed by the employment of energy based design optimization principles to solve the inverse problem that determines the unknown parameters of the constitutive model under consideration. In order to validate identified constitutive models, finite element simulations using these models were exercised for three distinct specimen geometries. The first geometry was that of the characterization coupon under multiaxial loading. The second was that of open hole specimens in tension. The final one was that of stiffened panel substructures under tension. Actual experimental data from testing all these specimens were collected by the use of load cells, full field displacement and strain methods and strain gauges. Finally, the theoretical predictions were compared with the experimental ones in terms of strain field distributions and load-strain responses. The comparisons demonstrated excellent predictability of the determined constitutive responses with the predictions always within the error band of the methods used to collect the experimental data.
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Manzari, Majid T., Wenjun Zeng, Yin-Lin Shen e James D. Lee. "A Physically Based Constitutive Model for Ferroelectrics". In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42878.
Testo completoAbstract (sommario):
Ferroelectric ceramics are widely used to exploit the piezoelectric effect in various electrical and mechanical equipment and devices such as ultrasonic generators, filters, hydrophones, pressure sensors, accelerometers, actuators, and adjustable aerodynamic surfaces. Despite their high potential for the use in many new engineering applications, there are several complications that limit their application to relatively low-level stress, electric field, and temperature conditions. One of the most important limitations is the fact that ferroceramics experience phase transformation or phase twinning that lead to their nonlinear response to electrical and/or mechanical loading. This is the main reason for the common design practice that limits the use of ferroelectric components to relatively small stress/electric field levels where the material behavior is linear and the measured piezoelectric properties of the material can be used with confidence. Hence there is a need for developing accurate nonlinear constitutive models for ferroelectric ceramics. This paper presents a physically based macroscopic constitutive model that can be used in the analysis of devices involving ferroelectric ceramics. It is assumed that the material point at each Gauss point of a typical finite element represents an aggregate of n unit cells distributed in a manner that the c-axis of each cell is oriented in a specific direction. The intial distribution of the orientations of the unit cells depends on whether the material is already poled or not. Once the strain increment for each unit cell is calculated, the corresponding stress tensor is computed by using the linear relationship between the stress and strain tensors in the cell’s local coordinate system. An appropriate domain-switching criterion is then checked for each unit cell. If the criterion is met, then the polarization orientation is switched for that cell and the orientation of the c-axis for that unit cell is updated. The constitutive moduli for the aggregate of unit cells are then calculated by using a homogenization technique. Using this approach it is clear that a nonlinear constitutive relationship is generated as soon as one of the unit cells in the aggregate switches its polarization direction. The nonlinearity of the response becomes more obvious as the polarization directions in more elements switch. This will lead to a hardening regime. As more elements switch and the number of elements that can potentially switch become smaller, the response of the system starts to become mainly affected by the constitutive response of the switched element, albeit in their new directions. This will lead to a stiffening part in the constitutive relationship, which eventually asymptotes to a linear relationship as the tendency to switching of the unit cells saturates and most of the unit cells in the aggregate become fully oriented toward the new polarization direction. This closely mimics the observed response of ferroelectric ceramics. Numerical simulations of compression of a poled PZT specimen by using the aforementioned constitutive model show close correlation of the simulations with the experimental data available for PZT materials.
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van Soestbergen, M., e J. J. M. Zaal. "Predictive modeling of competing failure mechanisms using a dedicated constitutive relation for solder alloy". In 2018 7th Electronic System-Integration Technology Conference (ESTC). IEEE, 2018. http://dx.doi.org/10.1109/estc.2018.8546363.
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Tzou, H. S., e W. K. Chai. "Constitutive Modeling of Controllable Electrostrictive Structronic Thin Shells". In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32328.
Testo completoAbstract (sommario):
Electrostrictive material is one of the key smart materials, with tremendous potentials in many engineering applications, e.g., sonar, actuators, artificial muscles, etc. The (direct) electrostrictive effect of electrostrictive materials is a quadratic dependence of stress or strain on applied electric field and this nonlinear electromechanical effect contributes significant actuation performance as compared with that of conventional piezoelectric materials. A generic electrostrictive thin shell theory and its dynamic electro-mechanical system equations are derived based on a generic double-curvature thin shell defined in the paraelectric phase. Generic mathematical models and permissible boundary conditions of electrostrictive thin shells are defined based on Hamilton’s principle, elasticity theory, Kirchhoff-Love thin shell theory and Gibbs elastic free energy function. Electro-mechanical behaviors and dynamic characteristics of electrostrictive shells are evaluated. Simplifications of the generic electrostrictive shell theory to other common geometries are demonstrated, electrostrictive/dynamic coupling equations derived, and their electromechanical characteristics discussed.
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Heaney, Patrick S., e Onur Bilgen. "Nonlinearities in Experimental System Identification of a Piezocomposite Beam Model". In ASME 2017 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/smasis2017-3735.
Testo completoAbstract (sommario):
Piezocomposite beams are often modeled using linear constitutive equations describing the electromechanical coupling of the material. In nearly all experimental identification processes, nonlinearities in these equations are ignored, which can lead to significant errors in the identified models. Following a common practice in the literature, a piezocomposite cantilever beam is modeled as a single degree of freedom system, with strain induced harmonic excitation governed by linear piezoelectric constitutive relationships. The validity of the linear property assumptions is investigated. It is experimentally demonstrated that the relationship between input and response of the beam is significantly nonlinear. The impact of this nonlinear behavior on the parameter identification of the system is shown for three different testing methods, (1) Open Loop Excitation, (2) Constant Input, and (3) Constant Response. For each method, the command amplitude is varied which yields different parameter estimates for the single degree of freedom beam model. These results demonstrate that the assumed linear constitutive relationships lead to parameter estimates which are only accurate for the specific testing method and the specific commanded input or response amplitude, even under highly controlled testing procedures. The paper concludes with comments on the system identification of a single degree of freedom model given this nonlinear system behavior.
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Tao, Fei, Xin Liu, Haodong Du e Wenbin Yu. "Learning damage constitutive law of composites via lamination theory enhanced Abaqus-PDNN mechanics system". In AIAA Scitech 2021 Forum. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2021. http://dx.doi.org/10.2514/6.2021-2022.
Testo completoRapporti di organizzazioni sul tema "Constitutive system"
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Weeks, Timothy "Dash". DTPH56-13-X-000013 Modern High-Toughness Steels for Fracture Propagation and Arrest Assessment-Phase II. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), settembre 2018. http://dx.doi.org/10.55274/r0012037.
Testo completoAbstract (sommario):
NIST work developed processes to identify the stress/strain/crack velocity conditions for unstable high-rate ductile crack propagation found in a full-scale pipeline burst test and duplicate those conditions in a medium-scale test. With modeling to validate conditions and assumptions used in reducing the scale of the tests. A medium-scale test to elucidate material property data necessary to qualify high-strength high-toughness steels based on the correlation to large-scale tests. Parametric determination of the material properties governing fracture propagation or arrest-ability was developed. This will assist researchers to determine a relevant and effective small-scale test (or tests) that provides enough information for material selection, design, reliability, as well as integrity and risk assessment. Pipe evaluated includes API5L X70 and X80 pipe. The strain was measured by a three-dimensional digital image correlation system. This project takes a phased approach with complementary research in successive phases beginning with a road map to systematically fill gaps in knowledge and understanding of the problem of unstable high-rate ductile running failures in pipelines. This report is structured to highlight the problem statement with respect to the current state of the art understanding, define knowledge gaps and present the plan, and progress toward meeting the objective. The following sections specifically cover the effort to develop and inform a constitutive material model necessary for the structural model of the medium-scale test. The material testing required to inform the constitutive material model is presented. Conclusions of this phase of the project are also presented in addition to the proposed work in Phase III of the project.
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Pullammanappallil, Pratap, Haim Kalman e Jennifer Curtis. Investigation of particulate flow behavior in a continuous, high solids, leach-bed biogasification system. United States Department of Agriculture, gennaio 2015. http://dx.doi.org/10.32747/2015.7600038.bard.
Testo completoAbstract (sommario):
Recent concerns regarding global warming and energy security have accelerated research and developmental efforts to produce biofuels from agricultural and forestry residues, and energy crops. Anaerobic digestion is a promising process for producing biogas-biofuel from biomass feedstocks. However, there is a need for new reactor designs and operating considerations to process fibrous biomass feedstocks. In this research project, the multiphase flow behavior of biomass particles was investigated. The objective was accomplished through both simulation and experimentation. The simulations included both particle-level and bulk flow simulations. Successful computational fluid dynamics (CFD) simulation of multiphase flow in the digester is dependent on the accuracy of constitutive models which describe (1) the particle phase stress due to particle interactions, (2) the particle phase dissipation due to inelastic interactions between particles and (3) the drag force between the fibres and the digester fluid. Discrete Element Method (DEM) simulations of Homogeneous Cooling Systems (HCS) were used to develop a particle phase dissipation rate model for non-spherical particle systems that was incorporated in a two-fluid CFDmultiphase flow model framework. Two types of frictionless, elongated particle models were compared in the HCS simulations: glued-sphere and true cylinder. A new model for drag for elongated fibres was developed which depends on Reynolds number, solids fraction, and fibre aspect ratio. Schulze shear test results could be used to calibrate particle-particle friction for DEM simulations. Several experimental measurements were taken for biomass particles like olive pulp, orange peels, wheat straw, semolina, and wheat grains. Using a compression tester, the breakage force, breakage energy, yield force, elastic stiffness and Young’s modulus were measured. Measurements were made in a shear tester to determine unconfined yield stress, major principal stress, effective angle of internal friction and internal friction angle. A liquid fludized bed system was used to determine critical velocity of fluidization for these materials. Transport measurements for pneumatic conveying were also assessed. Anaerobic digestion experiments were conducted using orange peel waste, olive pulp and wheat straw. Orange peel waste and olive pulp could be anaerobically digested to produce high methane yields. Wheat straw was not digestible. In a packed bed reactor, anaerobic digestion was not initiated above bulk densities of 100 kg/m³ for peel waste and 75 kg/m³ for olive pulp. Interestingly, after the digestion has been initiated and balanced methanogenesis established, the decomposing biomass could be packed to higher densities and successfully digested. These observations provided useful insights for high throughput reactor designs. Another outcome from this project was the development of low cost devices to measure methane content of biogas for off-line (US$37), field (US$50), and online (US$107) applications.
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Pachón, Mónica, Roberto Junguito e Mauricio Cárdenas. Political Institutions and Policy Outcomes in Colombia: The Effects of the 1991 Constitution. Inter-American Development Bank, febbraio 2006. http://dx.doi.org/10.18235/0011279.
Testo completoAbstract (sommario):
The 1991 Colombian Constitution strengthened the checks and balances of the political system by enhancing the role of Congress and the Constitutional Court, while somewhat limiting the powers of the President (who nonetheless remains extremely powerful even by Latin American standards). As a consequence of the larger number of relevant players, and the removal of barriers that restricted political participation, the political system has gained in terms of representation. However, political transaction costs have increased, making cooperation harder to achieve. The authors show that this has been typically the case in fiscal policy, where the use of rigid rules, the constitutionalization of some policies, and a reduction in legislative success rates-due to the presence of a more divided and fragmented Congress-have limited the adaptability and flexibility of policies. In contrast, in other areas of policy that were formally delegated to the technocracy, policies have been more adaptable to economic shocks, delivering better outcomes.
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Bray, Jonathan, Ross Boulanger, Misko Cubrinovski, Kohji Tokimatsu, Steven Kramer, Thomas O'Rourke, Ellen Rathje, Russell Green, Peter Robertson e Christine Beyzaei. U.S.—New Zealand— Japan International Workshop, Liquefaction-Induced Ground Movement Effects, University of California, Berkeley, California, 2-4 November 2016. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, marzo 2017. http://dx.doi.org/10.55461/gzzx9906.
Testo completoAbstract (sommario):
There is much to learn from the recent New Zealand and Japan earthquakes. These earthquakes produced differing levels of liquefaction-induced ground movements that damaged buildings, bridges, and buried utilities. Along with the often spectacular observations of infrastructure damage, there were many cases where well-built facilities located in areas of liquefaction-induced ground failure were not damaged. Researchers are working on characterizing and learning from these observations of both poor and good performance. The “Liquefaction-Induced Ground Movements Effects” workshop provided an opportunity to take advantage of recent research investments following these earthquake events to develop a path forward for an integrated understanding of how infrastructure performs with various levels of liquefaction. Fifty-five researchers in the field, two-thirds from the U.S. and one-third from New Zealand and Japan, convened in Berkeley, California, in November 2016. The objective of the workshop was to identify research thrusts offering the greatest potential for advancing our capabilities for understanding, evaluating, and mitigating the effects of liquefaction-induced ground movements on structures and lifelines. The workshop also advanced the development of younger researchers by identifying promising research opportunities and approaches, and promoting future collaborations among participants. During the workshop, participants identified five cross-cutting research priorities that need to be addressed to advance our scientific understanding of and engineering procedures for soil liquefaction effects during earthquakes. Accordingly, this report was organized to address five research themes: (1) case history data; (2) integrated site characterization; (3) numerical analysis; (4) challenging soils; and (5) effects and mitigation of liquefaction in the built environment and communities. These research themes provide an integrated approach toward transformative advances in addressing liquefaction hazards worldwide. The archival documentation of liquefaction case history datasets in electronic data repositories for use by the broader research community is critical to accelerating advances in liquefaction research. Many of the available liquefaction case history datasets are not fully documented, published, or shared. Developing and sharing well-documented liquefaction datasets reflect significant research efforts. Therefore, datasets should be published with a permanent DOI, with appropriate citation language for proper acknowledgment in publications that use the data. Integrated site characterization procedures that incorporate qualitative geologic information about the soil deposits at a site and the quantitative information from in situ and laboratory engineering tests of these soils are essential for quantifying and minimizing the uncertainties associated site characterization. Such information is vitally important to help identify potential failure modes and guide in situ testing. At the site scale, one potential way to do this is to use proxies for depositional environments. At the fabric and microstructure scale, the use of multiple in situ tests that induce different levels of strain should be used to characterize soil properties. The development of new in situ testing tools and methods that are more sensitive to soil fabric and microstructure should be continued. The development of robust, validated analytical procedures for evaluating the effects of liquefaction on civil infrastructure persists as a critical research topic. Robust validated analytical procedures would translate into more reliable evaluations of critical civil infrastructure iv performance, support the development of mechanics-based, practice-oriented engineering models, help eliminate suspected biases in our current engineering practices, and facilitate greater integration with structural, hydraulic, and wind engineering analysis capabilities for addressing multi-hazard problems. Effective collaboration across countries and disciplines is essential for developing analytical procedures that are robust across the full spectrum of geologic, infrastructure, and natural hazard loading conditions encountered in practice There are soils that are challenging to characterize, to model, and to evaluate, because their responses differ significantly from those of clean sands: they cannot be sampled and tested effectively using existing procedures, their properties cannot be estimated confidently using existing in situ testing methods, or constitutive models to describe their responses have not yet been developed or validated. Challenging soils include but are not limited to: interbedded soil deposits, intermediate (silty) soils, mine tailings, gravelly soils, crushable soils, aged soils, and cemented soils. New field and laboratory test procedures are required to characterize the responses of these materials to earthquake loadings, physical experiments are required to explore mechanisms, and new soil constitutive models tailored to describe the behavior of such soils are required. Well-documented case histories involving challenging soils where both the poor and good performance of engineered systems are documented are also of high priority. Characterizing and mitigating the effects of liquefaction on the built environment requires understanding its components and interactions as a system, including residential housing, commercial and industrial buildings, public buildings and facilities, and spatially distributed infrastructure, such as electric power, gas and liquid fuel, telecommunication, transportation, water supply, wastewater conveyance/treatment, and flood protection systems. Research to improve the characterization and mitigation of liquefaction effects on the built environment is essential for achieving resiliency. For example, the complex mechanisms of ground deformation caused by liquefaction and building response need to be clarified and the potential bias and dispersion in practice-oriented procedures for quantifying building response to liquefaction need to be quantified. Component-focused and system-performance research on lifeline response to liquefaction is required. Research on component behavior can be advanced by numerical simulations in combination with centrifuge and large-scale soil–structure interaction testing. System response requires advanced network analysis that accounts for the propagation of uncertainty in assessing the effects of liquefaction on large, geographically distributed systems. Lastly, research on liquefaction mitigation strategies, including aspects of ground improvement, structural modification, system health monitoring, and rapid recovery planning, is needed to identify the most effective, cost-efficient, and sustainable measures to improve the response and resiliency of the built environment.
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Ciapponi, Agustín, e Sebastián García Martí. Are interventions to increase hand hygiene among healthcare workers effective? SUPPORT, 2016. http://dx.doi.org/10.30846/1608107.
Testo completoAbstract (sommario):
Healthcare-associated infections are a major cause of morbidity and mortality, and constitute a significant burden on health systems. Hand hygiene is regarded as an effective preventive measure but the frequency of hand hygiene by healthcare workers is low.
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Zaman, Tahir, Michael Collyer, Rachel Sabates-Wheeler e Carolina Szyp. Beyond Rights-Based Social Protection for Forcibly Displaced People. Institute of Development Studies (IDS), febbraio 2022. http://dx.doi.org/10.19088/basic.2022.006.
Testo completoAbstract (sommario):
Having a right that is not respected is not the same as having no right at all. At least this should not be the case. Failure to receive something to which you are entitled should lead to formal redress or failing that, protest. The rights-based discourse has a wider importance. If and when it is or should be used is significant. In terms of access to social protection (including social and humanitarian assistance), the rights-based discourse means there is no difference between refugees and others who fail to receive the protection to which they are entitled, such as Internally Displaced People (IDPs). This introduces two key tensions, both of which we explore in this paper. The first concerns the identification of the institution responsible for fulfilling the right, as determined in state-led/formal humanitarian system of social protection. The second concerns the alternatives displaced people may identify when Northern mandated forms of social protection fail, or when the conditions for the enjoyment of that protection are too onerous. These alternatives constitute a second system of social protection. We conclude that although they are unequal, both systems are currently necessary, even as a language of rights is only appropriate in relation to the first tension. Ultimately greater coordination and collaboration between the two systems is necessary.
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O'Neill, Sharman, Abraham Halevy e Amihud Borochov. Molecular Genetic Analysis of Pollination-Induced Senescence in Phalaenopsis Orchids. United States Department of Agriculture, 1991. http://dx.doi.org/10.32747/1991.7612837.bard.
Testo completoAbstract (sommario):
The project investigated the molecular genetic and biochemical basis of pollination-induced senescence of Phalaenopsis flowers. This experimental system offered unique advantages in that senescence is strictly regulated by pollination, providing the basis to experimentally initiate and synchronize senescence in populations of flowers. The postpollination syndrome in the Phalaenopsis orchid system was dissected by investigating the temporal and spatial regulation of ACC synthase gene expression. In the stigma, pollen-borne auxin induces the expression of the auxin-regulated ACC synthase (PS-ACS2) gene, resulting in ACC synthesis within 1 h following pollination. Newly formed ACC is oxidized by basal constitutive ACC oxidase to ethylene, which then induces the expression of the ethylene-regulated ACC synthase(PS-ACS1) and oxidase (ACO1) genes for further autocatalytic production of ethylene. It is speculated that during the 6-h period following pollination, emasculation leads to the production or release of a sensitivity factor that sensitizes the cells of the stigma to ethylene. ACC and ethylene molecules are translocated from the stigma to the labellum and perianth where ethylene induces the expression of PS-ACS1 and ACO1 resulting in an increased production of ACC and ethylene. Organ-localized ethylene is responsible for inrolling and senescence of the labellum and perianth. The regulation of ethylene sensitivity and signal transduction events in pollinated flowers was also investigated. The increase in ethylene sensitivity appeared in both the flower column and the perianth, and was detected as early as 4 h after pollination. The increase in ethylene sensitivity following pollination was not dependent on endogenous ethylene production. Application of linoleic and linoleic acids to Phalaenopsis and Dendrobium flowers enhanced their senescence and promoted ethylene production. Several major lipoxygenase pathway products including JA-ME, traumatic acid, trans-2-hexenal and cis-3-hexenol, also enhanced flower senescence. However, lipoxygenase appears to not be directly involved in the endogenous regulation of pollination-induced Phalaenopsis and Dendrobium flower senescence. The data suggest that short-chain saturated fatty acids may be the ethylene "sensitivity factors" produced following pollination, and that their mode of action involves a decrease in the order of specific regions i the membrane lipid bilayer, consequently altering ethylene action. Examination of potential signal transduction intermediates indicate a direct involvement of GTP-binding proteins, calcium ions and protein phosphorylation in the cellular signal transduction response to ethylene following pollination. Modulations of cytosolic calcium levels allowed us to modify the flowers responsiveness to ethylene.
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Bhandari, Usha. Power struggle in the Technical and Vocational Education and Training (TVET) sector in Nepal. Fribourg (Switzerland): IFF, 2023. http://dx.doi.org/10.51363/unifr.diff.2023.37.
Testo completoAbstract (sommario):
The governance of Technical and Vocational Education and Training (TVET) in Nepal was heavily centralized in the past as the country was operating under a unitary government system. The 2015 Constitution has opened the avenue to operate the TVET sector in a federalized setting with the sharing of TVET functions along with power and authority by three tiers of government. However, the sharing of power and authority between the federal and subnational governments has not been easy as highlighted by the Constitution. This paper attempts to analyse the challenges that are hindering the smooth transition of centrally held power and authority towards the subnational governments. It argues that although there is a general support and optimism for the federal transition, many challenges remain for the implementation. The existing political economy of the TVET sector limits the realisation of the Constitution’s goals of transformation for the TVET sector in a federal setting.
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Cundiff, Kenneth. Calibrating the SPECTACULAR constitutive model using legacy Sandia data for two filled epoxy systems: 828/CTBN/DEA/GMB and 828/DEA/GMB. Office of Scientific and Technical Information (OSTI), maggio 2022. http://dx.doi.org/10.2172/1867984.
Testo completo
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Rezende, Fernando. Brazil's ICMS Tax: Origin, Changes, Current Situation, and Paths to Recovery. Inter-American Development Bank, agosto 2013. http://dx.doi.org/10.18235/0006967.
Testo completoAbstract (sommario):
The tax reform of 1965 in Brazil sought to streamline state taxation, replacing the old tax on sales and consignment (IVC) with a modern value added tax on the circulation of goods (ICM) as part of a profound change that aimed to build a national tax system. During the process of drafting the 1988 Constitution, the foundation of the ICM was expanded to include services and renamed ICMS. However, these changes have created increasing problems for the economy and the federation, which have worsened as successive attempts at reform have failed. Repeated attempts to improve the Brazilian tax system by adopting ad hoc measures have had little success. The diversity of interests and the complexity of the situation do not allow for isolated measures to make a big difference. It is important to seize the opportunity to advance towards a better understanding of the reforms in order to correct the many distortions that have accumulated in the tax system over more than four decades. For the first time, the federal issue precedes the discussion of tax reform.