196,075 research outputs found
An enhanced beam model of the asymmetric double cantilever beam (ADCB) test for composite laminates
No full textThe paper introduces a mechanical model of the asymmetric double cantilever beam (ADCB) test, usable to assess the mixed-mode interlaminar fracture toughness of composite laminates. The laminated specimen is represented as an assembly of sublaminates, each of which is modelled as an elastic beam partly connected to the other by a deformable interface, in turn considered to be a continuous distribution of elastic-brittle springs. Based on Timoshenko’s beam theory, a set of six differential equations, accompanied by suitable boundary conditions, governs the problem. By adopting the interfacial stresses as the main unknowns, the differential problem is solved analytically, and the contributions of the opening and sliding fracture modes are evaluated directly. Moreover, explicit expressions are determined for the interfacial stresses, internal forces, and displacements, as well as for the compliance, energy release rate, and mode-mixity angle. The predictions of the model are to some extent similar to those of analogous mechanical models in the literature and appear in good agreement with both numerical and experimental results
An enhanced beam-theory model of the asymmetric double cantilever beam (ADCB) test for composite laminates
No full textThe paper introduces a mechanical model of the asymmetric double cantilever beam (ADCB) test, usable to assess the mixed-mode interlaminar fracture toughness of composite laminates. The laminated specimen is represented as an assembly of sublaminates, each of which is modelled as an elastic beam partly connected to the other by a deformable interface, in turn considered to be a continuous distribution of elastic-brittle springs. Based on Timoshenko’s beam theory, a set of six differential equations, accompanied by suitable boundary conditions, governs the problem. By adopting the interfacial stresses as the main unknowns, the differential problem is solved analytically, and the contributions of the opening and sliding fracture modes are evaluated directly. Moreover, explicit expressions are determined for the interfacial stresses, internal forces, and displacements, as well as for the compliance, energy release rate, and mode-mixity angle. The predictions of the model are to some extent similar to those of analogous mechanical models in the literature and appear in good agreement with both numerical and experimental results
Erratum to “An enhanced beam-theory model of the asymmetric double cantilever beam (ADCB) test for composite laminates” [Compos Sci Technol 2009;69(11-12):1735-1745]
No full textFrattura interlaminare secondo il modo I in un laminato composito
No full textSi propone un modello meccanico per il provino DCB (Double Cantilever Beam), comunemente utilizzato per la determinazione sperimentale della resistenza alla frattura interlaminare secondo il modo I nei laminati compositi. A tal fine, si schematizza il provino come l’assemblaggio di due sublaminati collegati fra loro da un’interfaccia elasto-fragile. Grazie alla relativa semplicità del modello, è possibile ricavare esplicitamente gli spostamenti dei due sublaminati, le tensioni interlaminari e, conseguentemente, la velocità di rilascio dell’energia potenziale totale del sistema. L’adozione di un opportuno criterio di frattura consente, quindi, di valutare il valore critico del carico o dello spostamento di estremità, come funzioni esplicite dell’ampiezza della zona delaminata. Il confronto con alcuni risultati sperimentali presenti in letteratura appare molto buono
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
Biomarkers of browning in cold exposed siberian adults
No full textCold-exposure promotes energy expenditure by inducing brown adipose tissue (BAT) thermogenesis, which over time, is also sustained by browning, the appearance, or increase, of brown-like cells into white fat depots. Identification of circulating markers reflecting BAT activity and browning is crucial to study this phenomenon and its triggers, also holding possible implications for the therapy of obesity and metabolic diseases. Using RT-qPCR, we evaluated the peripheral blood mononuclear cells (PBMC) expression profile of regulators of BAT activity (CIDEA, PRDM16), white adipocytes browning (HOXC9 and SLC27A1), and fatty acid β-oxidation (CPT1A) in 150 Siberian healthy miners living at extremely cold temperatures compared to 29 healthy subjects living in thermoneutral conditions. Anthropometric parameters, glucose, and lipid profiles were also assessed. The cold-exposed group showed significantly lower weight, BMI, hip circumference, and PBMC expression of CIDEA, but higher expression of HOXC9 and higher circulating glucose compared to controls. Within the cold-exposed group, BMI, total cholesterol, and the atherogenic coefficient were lower in individuals exposed to low temperatures for a longer time. In conclusion, human PBMC expresses the brown adipocytes marker CIDEA and the browning marker HOXC9, which, varying according to cold-exposure, possibly reflect changes in BAT activation and white fat browning
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Role of gremlin-1 in the pathophysiology of the adipose tissues
No full textGremlin-1 is a secreted bone morphogenetic protein (BMP) antagonist playing a pivotal role in the regulation of tissue formation and embryonic development. Since its first identification in 1997, gremlin-1 has been shown to be a multifunctional factor involved in wound healing, inflammation, cancer and tissue fibrosis. Among others, the activity of gremlin-1 is mediated by its interaction with BMPs or with membrane receptors such as the vascular endothelial growth factor receptor 2 (VEGFR2) or heparan sulfate proteoglycans (HSPGs). Growing evidence has highlighted a central role of gremlin-1 in the homeostasis of the adipose tissue (AT). Of note, gremlin-1 is involved in AT dysfunction during type 2 diabetes, obesity and non-alcoholic fatty liver disease (NAFLD) metabolic disorders. In this review we discuss recent findings on gremlin-1 involvement in AT biology, with particular attention to its role in metabolic diseases, to highlight its potential as a prognostic marker and therapeutic target
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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