Superbrittleness of rocks and earthquake activity Tarasov, B.G.; Randolph, M.F.
International journal of rock mechanics and mining sciences (Oxford, England : 1997),
09/2011, Letnik:
48, Številka:
6
Journal Article
Recenzirano
This paper demonstrates that, in contrast to relatively soft rocks, intact hard rocks failed in mode II can increase their brittleness dramatically (hundreds of times) with rising confining stress. ...The brittleness variation in this case follows a typical pattern of initially increasing, reaching a maximum and then ultimately decreasing. The harder the rock, the greater is the effect of embrittlement. A shear rupture mechanism discussed in the paper shows that the embrittlement results from reduction of friction within the rupture zone with rising confining stress. Transient “negative friction”, which can be generated within a certain range of confining stress renders rocks superbrittle. The similarity in variation of rock brittleness with confining stress, and aftershock activity with depth, leads to the supposition that the aftershock process can be caused by generation of new faults in the intact rock mass surrounding the main fault where superbrittle behaviour determines the depth range of earthquake activity.
► We examine hard rock embrittlement due to rising confining pressure. ► The embrittlement is caused by reduction of friction in the shear rupture head. ► Transient “negative friction” renders rocks superbrittle. ► Superbrittleness of rocks can determine the depth range of earthquake activity.
This book examines how selected works of fiction advocate for just memories and promote identities that accept ethical agency and that exercise power and control over their own lives and destinies, ...no matter how limited such control may be.
On the Run in Siberia is the chilling tale of living in exile among Yukaghir hunters in the stark Siberian taiga region—a story of idealism, political corruption, starvation, and survival. It is also ...a striking portrait of the Yukaghirs’ shamanistic tradition and their threatened way of life, a drama unfolding daily in one of the world’s coldest, most enthralling landscapes.
Socialist Review Book Award, Socialist Review, 1987 This volume makes available in one place a complete statement of Fred Block's perspective for students and participants in the ongoing debate on ...state theory. His substantial Introduction serves as an intellectual autobiography in which he assesses the field-including the theories of Domhoff, Poulantzas, and Skocpoland situates his own work within it. Block also discusses his relationship to different strands of Marxism. In his analysis of the relationship between business and the state, Block argues that while business interests have far more influence over state policy than other constituencies, state actors still have substantial autonomy in formulating policies. In particular, the business community's internal divisions and difficulties in assessing its own interests limit its capacity to control events. Block insists that when business influence is greatest, as during the Reagan years, state policies will be least successful in solving the society's problems. "What is at work here is a relatively simple sociological dynamic--that institutionalized relations of power tend to become visible only when they weaken. When these institutionalized relations are most effective, they tend to be invisible, precisely because the justifying ideologies so dominate people's commonsense understandings. The classic recent example is the existence of women's subordination. In the fifties, people would have responded to the claim that women were systematically discriminated against in American society with incredulity because they had so totally accepted an ideology that justified differential treatment of men and women as normal and natural. The full-blown analysis and critique of male domination emerges only in the seventies, when patriarchal arrangements are already weakening... "In state theory, the development is analogous. In the fifties, pluralist arguments dominate because the exercise of power has been rendered invisible. The relation between business and the state works so well that it leaves few traces. Moreover, there is little real debate about how the society should be structured, so the extent to which everyone's basic assumptions fit with the interests of corporate capitalism is not at all obvious. Since nobody was even asking the big questions of who should make investment decisions and how should income and wealth be distributed, it was not apparent that the narrow limits of debate fit exactly with the interests of business... However, the cumulative impact of Vietnam and racial conflict in the late sixties, the drama of Watergate, and the growing economic difficulties of advanced capitalist societies in the early seventies served to make the exercise of power in American society widely visible. The previous functional relation between the state and business had been disrupted and the efforts by each side to advocate its own interests became more apparent." --From the Introduction
InPBi was predicted to be the most robust infrared optoelectronic material but also the most difficult to synthesize within In-VBi (V = P, As and Sb) 25 years ago. We report the first successful ...growth of InPBi single crystals with Bi concentration far beyond the doping level by gas source molecular beam epitaxy. The InPBi thin films reveal excellent surface, structural and optical qualities making it a promising new III-V compound family member for heterostructures. The Bi concentration is found to be 2.4 ± 0.4% with 94 ± 5% Bi atoms at substitutional sites. Optical absorption indicates a band gap of 1.23 eV at room temperature while photoluminescence shows unexpectedly strong and broad light emission at 1.4-2.7 μm which can't be explained by the existing theory.
The building regulation system that was initiated in 1850 with the adoption of the ‘Regulation on the Admission of Civil Engineering Students and the Introduction of State Examinations in Civil ...Engineering’ in the Austrian Empire was repealed in 1946, through the ‘Law on the Invalidity of Legal Regulations Adopted Before 6 April 1941 and During the Enemy Occupation’. The new socialist building regulation system was created through the regulations of the Yugoslav government from 1947 on; it was acceptable to use certain repealed regulations until new ones were enacted, provided they did not conflict with the newly-created socialist legal system of the Federal People’s Republic of Yugoslavia. After the Federal Ministry of Construction was abolished in 1950, the technical regulations and standards were regulated at the federal level, while the administrative procedures and other legal regulations were gradually lowered to the level of the republics, including Croatia. So as to help architects, spatial planners, and other experts in the building process orient themselves in this jungle of regulations, architect Vladimir Šilhard (Schilchard) published the Revision Book of Building Regulations and Procedure in the P. R. of Croatia in the professional journal Čovjek i prostor (Man and Space) in 1956. This article also exhaustively presents and analyses the building regulations in the period from 1946, through Šilhard’s unified compendium, to the enactment of the Zagreb City Master Plan in 1971. On the one hand, the 1960s period was a great challenge for adopting regulations, primarily due to the new way of building residential buildings, which were not encompassed by the then existing regulations. On the other hand, new urban legislation was needed after Zagreb spread over the river Sava to the south, where the Zagreb Fair and the first residential neighbourhoods were built, so that the city could maintain a sustainable appearance of modernity. In this sense, the master plan of 1971 represented the peak of city planning that had begun with a competition for the for the General Regulatory Basis in 1930–1931 and the enactment of the Building Regulations of 1940. The system of technical regulations and building regulation standards on the federal level was mostly complete by late 1971, and remained partially in force even after the Republic of Croatia declared its independence on 8 October 1991, lasting until Croatia joined the European Union on 1 July 2013.
We revisited the young Large Magellanic Cloud star cluster NGC 1971 with the aim of providing additional clues to our understanding of its observed extended main-sequence turnoff (eMSTO), a feature ...commonly seen in young star clusters that has recently been argued to be caused by a real age spread similar to the cluster age (∼160 Myr). We combined accurate Washington and Strömgren photometry of stars with high membership probability to explore the nature of this eMSTO. From different ad hoc defined pseudo-colors, we found that bluer and redder stars distributed throughout the eMSTO do not show any inhomogeneities of light- and heavy-element abundances. These blue and red stars are split into two clearly different groups only when the Washington
M
magnitudes are employed, which delimites the number of spectral features that cause the appearance of the eMSTO. We speculate that Be stars populate the eMSTO of NGC 1971 because (i) H
β
contributes to the
M
passband, (ii) H
β
emissions are common features of Be stars, and (iii) the Washington
M
and
T
1
magnitudes are tightly correlated; the latter measuring the observed contribution of H
α
emission line in Be stars, which is in turn correlated with H
β
emissions. This is the first observational result to our knowledge that indicates that H
β
emissions are the origin of eMSTOs observed in young star clusters. Our results certainly open new possibilities of studying eMSTO from photometric systems with passbands centered at features commonly seen in Be stars.
The purpose of this study was to compare outcomes (and the effect of sacubitril/valsartan) according to etiology in the PARADIGM-HF (Prospective comparison of angiotensin-receptor-neprilysin ...inhibitor ARNI with angiotensin-converting-enzyme inhibitor ACEI to Determine Impact on Global Mortality and morbidity in Heart Failure) trial.
Etiology of heart failure (HF) has changed over time in more developed countries and is also evolving in non-Western societies. Outcomes may vary according to etiology, as may the effects of therapy.
We examined outcomes and the effect of sacubtril/valsartan according to investigator-reported etiology in PARADIGM-HF. The outcomes analyzed were the primary composite of cardiovascular death or HF hospitalization, and components, and death from any cause. Outcomes were adjusted for known prognostic variables including N terminal pro-B type natriuretic peptide.
Among the 8,399 patients randomized, 5,036 patients (60.0%) had an ischemic etiology. Among the 3,363 patients (40.0%) with a nonischemic etiology, 1,595 (19.0% of all patients; 47% of nonischemic patients) had idiopathic dilated cardiomyopathy, 968 (11.5% of all patients; 28.8% of nonischemic patients) had a hypertensive cause, and 800 (9.5% of all patients, 23.8% of nonischemic patients) another cause (185 infective/viral, 158 alcoholic, 110 valvular, 66 diabetes, 30 drug-related, 14 peripartum-related, and 237 other). Whereas the unadjusted rates of all outcomes were highest in patients with an ischemic etiology, the adjusted hazard ratios (HRs) were not different from patients in the 2 major nonischemic etiology categories; for example, for the primary outcome, compared with ischemic (HR: 1.00), hypertensive 0.87 (95% confidence interval CI: 0.75 to 1.02), idiopathic 0.92 (95% CI: 0.82 to 1.04) and other 1.00 (95% CI: 0.85 to 1.17). The benefit of sacubitril/valsartan over enalapril was consistent across etiologic categories (interaction for primary outcome; p = 0.11).
Just under one-half of patients in this global trial had nonischemic HF with reduced ejection fraction, with idiopathic and hypertensive the most commonly ascribed etiologies. Adjusted outcomes were similar across etiologic categories, as was the benefit of sacubitril/valsartan over enalapril. (Efficacy and Safety of LCZ696 Compared to Enalapril on Morbidity and Mortality of Patients With Chronic Heart Failure; NCT01035255).
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