The behavior of transversely isotropic rock material was studied under Brazilian test conditions for nine different rocks (two sandstones, one shale, two slates, one schist, and three gneiss). Both ...the variation of the strength and the final fracture patterns induced by testing were examined as a function of the inclination angle of the weak planes. The combination of the observations for both parameters illustrated clearly the complexity of the failure of such rocks, which was summarized by assuming four different trends. The four trends for the variation of the strength as a function of the inclination angles range from little or no variation (trend 1, i.e., isotropic behavior for strength) to a sharp decrease of the strength from very small angles onwards, followed by a leveling off (trend 4). Trend 2 is characterized by a constant value between 0° and about 45°, followed by a linear decrease, while trend 3 corresponds to a decrease of the strength over the entire interval, but a rather systematic decrease, approximating a linear variation. Different variations were observed among these four trends in terms of the relative lengths of the respective fractures along the weak planes and in any other direction. For the rocks investigated, there is a cross-over from dominant fractures in directions other than the weak planes to dominant fractures along the weak planes. For the four trends, there are systematic changes in the position of this cross-over point, i.e., on average, at about an inclination angle of 75° for trend 1 and at about 15° for trend 4. For inclination angles larger than the cross-over point, the rock specimens failed primarily by splitting between both loading lines.
•The complex behavior of transversely isotropic rock material is studied.•The paper focuses on nine different rocks under Brazilian test conditions.•The variation of strength as a function of the inclination angles is compared.•Different types of fractures are described.•The relative length of the different fractures is estimated.
Different failure modes of the bridge column under vehicle collision.
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•Vehicle collision colliding with bridge columns.•New model for the peak impact force.•Effect of engine’s mass to ...failure of bridge columns.•Quantify the shear force, bending moment, and inertia force.•Explanation for most common failure modes of columns in real impact accidents.
The dynamic responses and failure modes of reinforced concrete bridge columns under vehicle collision have been numerically investigated in this study by using a numerical model verified against some experimental testing data. The numerical results show that the Peak Impact Force (PIF) from the collision is governed by the vehicle engine and the vehicle velocity while the impulse of the impact force is influenced by the initial momentum of the total mass. It is, therefore, suggested that not only the total vehicle mass and the vehicle velocity but also the engine’s weight need to be considered to determine the impact force on structures under vehicle collision. The engine’s mass significantly affects the peak impact force, the moment, the shear force and thus the damage of the column. The lateral impact force considerably affects the column axial force and a relation between the PIF and the increase of the axial force is proposed for the design purpose. The numerical model is able to reproduce and provide an explanation of most of the common failure modes observed in real impact events including flexural failure, shear failure, and punching shear damage. In addition, the influences of four different methods of the superstructure modelling, i.e. uniformly distributed load, lumped mass, simplified beam model, and 3D detailed model on the behaviour of the bridge column under vehicle impact are also investigated.
In this paper, the adaptive fault compensation problem is investigated for high-speed trains in the presence of time-varying system parameters, disturbances, and actuator failures. To deal with the ...time-varying system parameters, a new time-varying indicator function instead of commonly used 0-1 function, is proposed to model the train dynamics as a piecewise model with unparameterizable time-varying disturbances, which can cover more time variations and help parametrization for adaptation. A backstepping adaptive controller is designed for the healthy system with unknown piecewise model parameters and known piecewise bounds on disturbances. For both the parameterizable and unparameterizable failures, the backstepping adaptive failure compensation with the adaptive laws are derived to achieve the position tracking under the known bound disturbances. The adaptive failure compensation for unknown bounds on disturbances is also discussed under the parameterizable failure. Through introducing the nonlinear damping in the proposed controller, the failure compensation controller is proposed for the model with unparameterizable system parameters to achieve an arbitrary degree of position tracking accuracy. The stability of the corresponding closed-loop system and asymptotic state tracking are proved via Lyapunov direct method, and validated using a high-speed train model.
Senseless Panic Isaac, William M
2012, 2012-06-25, 2012-06-19
eBook
The truth about the 2008 economic crisis from a Washington insiderThe 1980s opened with the prime interest rate at an astonishing 21.5 percent, leading to a severe recession with unemployment ...reaching nearly 11 percent. Depression-like conditions befell the country, the entire thrift industry was badly insolvent and the major money center banks were loaded with third world debt. Some 3,000 bank and thrifts failed, including nine of Texas’ ten largest, and Continental Illinois, which, at the time, was the seventh largest bank in the nation. These severe conditions were not only handled without creating a panic, the economy actually embarked on the longest peacetime expansion in history.In Senseless Panic: How Washington Failed America, William M. Isaac, Chairman of the Federal Deposit Insurance Corporation (FDIC) during the banking and SL crises of the 1980s, details what was different about 2008’s meltdown that allowed the failure of a comparative handful of institutions to nearly shut down the world’s financial system. The book also tells the rousing story of Isaac’s time at the FDIC.Details the mistakes that led to the panic of 2008 and 2009An updated paperback revision of the bestselling book on the 2008 economic crisis, including a fascinating new EpilogueDemystifies the conditions America faced in 2008Provides a road map for avoiding similar shutdowns and panics in the futureIncludes a foreword by Federal Reserve Chairman Paul VolckerSenseless Panicis a provocative, quick-paced, and thoughtful analysis of what went wrong with the nation's banking system, a blunt indictment of United States policy, and a road map for making sure it doesn’t happen again.
A levee failure occurred along the Secchia River, Northern Italy, on 19 January 2014, resulting in flood damage in excess of $500 million. In response to this failure, immediate surveillance of other ...levees in the region led to the identification of a second breach developing on the neighboring Panaro River, where rapid mitigation efforts were successful in averting a full levee failure. The paired breach events that occurred along the Secchia and Panaro Rivers provided an excellent window on an emerging levee failure mechanism. In the Secchia River, by combining the information content of photographs taken from helicopters in the early stage of breach development and 10 cm resolution aerial photographs taken in 2010 and 2012, animal burrows were found to exist in the precise levee location where the breach originated. In the Panaro River, internal erosion was observed to occur at a location where a crested porcupine den was known to exist and this erosion led to the collapse of the levee top. This paper uses detailed numerical modeling of rainfall, river flow, and variably saturated flow in the levee to explore the hydraulic and geotechnical mechanisms that were triggered along the Secchia and Panaro Rivers by activities of burrowing animals leading to levee failures. As habitats become more fragmented and constrained along river corridors, it is possible that this failure mechanism could become more prevalent and, therefore, will demand greater attention in both the design and maintenance of earthen hydraulic structures as well as in wildlife management.
Key Points:
Animal burrows are demonstrated to be a serious threat of earthen levee failure
Internal flow and erosion around a den can cause the collapse of the levee top
Internal flow may initiate due to direct inflow into the den or den wall failure
In-plane strength of masonry walls is affected by the resistant mechanisms activated in the walls, i.e., related to flexural or shear behavior. The latter one can occur in the walls according to ...different failure modes depending on both mortar and unit strengths and on the type of assembling, i.e., 'regular' or 'irregular' texture. In this paper, a critical review of the existing design formulations for the in-plane strength of masonry walls is firstly presented, with important information on the achievable failure modes depending on the geometrical and mechanical features of the masonry fabric. Then, experimental tests are collected from the literature and a comparison between theoretical and experimental results is carried out. The presented analyses are aimed to highlight the differences between the existing formulations and to identify the most suitable ones.
Setting forth the building blocks of banking bailout law, this book reconstructs a regulatory framework that might better serve countries during future crisis situations.
It builds upon recent, ...carefully selected case studies from the US, the EU, the UK, Spain and Hungary to answer the questions of what went wrong with the bank bailouts in the EU, why the US performed better in terms of crisis management, and how bailouts could be regulated and conducted more successfully in the future. Employing a comparative methodology, it examines the different bailout and bank resolution techniques and tools and identifies the pros and cons of the different legal and regulatory options and their underlying principles. In the post-2008 legal-regulatory architecture, financial institution–specific insolvency proceedings were further developed or implemented on both sides of the Atlantic. Ten years after the most recent financial crisis, there is sufficient empirical evidence to evaluate the outcomes of the bank bailouts in the US and the EU and to examine a number of cases under the EU’s new bank resolution regime.
This book will be of interest of anyone in the field of finance, banking, central banking, monetary policy and insolvency law.
Background
A creatinine-based estimation of the renal function lags behind the onset of disease process. Cystatin C is a new marker for acute kidney injury (AKI). However, data are limited in ...patients with acute-on-chronic liver failure (ACLF). We evaluated serum cystatin C as an early predictor of AKI in patients with ACLF.
Methods
In a prospective observational study, patients with ACLF and normal serum creatinine level were included in the study. Serum cystatin C was analyzed with the development of AKI and the disease outcome.
Result
Forty-seven patients (mean age: 43.26±16.34 years; male:female: 2.35:1) were included in the study. AKI developed in 34% of patients during the hospital stay. Receiver operating characteristic (ROC) curve analysis revealed that the best cutoff for baseline cystatin C was 1.47 mg/L with a sensitivity of 0.94 and specificity of 0.68. The cystatin C ((area under the curve AUC=0.853) performance was better than that of the creatinine (AUC=0.699), Child-Turcotte-Pugh (CTP) (AUC=0.661), and model for end-stage liver disease-sodium (MELD-Na) (AUC=0.641). In the univariate analysis, age, platelet count, creatinine, estimated glomerular filtration rate (eGFR)-modification of diet in renal disease (MDRD), cystatin C, and estimated glomerular filtration rate-serum cystatin C (eGFRcysC) were significantly associated with AKI in ACLF patients. Cystatin C was an independent positive predictor of AKI. Cystatin C was positively correlated with the MELD-Na scores (
r
=0.374 and
p
=0.009).
Conclusion
Our study supports previous studies reporting that serum cystatin C is a better predictor for AKI development compared to serum creatinine. Cystatin C may be used as an early marker for new-onset AKI in hospitalized patients with ACLF.
Robots are the next wave in service technology; however, this advanced technology is not perfect. This research examines how social perceptions regarding the warmth and competence of service robots ...influence consumer reactions to service failures and recovery efforts by robots. We argue that humanoid (vs. nonhumanoid) service robots are more strongly associated with warmth (whereas competence does not differ). This tendency to expect greater warmth from humanoid robots has important consequences for service firms: (i) consumers are more dissatisfied due to lack of warmth following a process failure caused by a humanoid (vs. nonhumanoid; Study 1); (ii) humanoids (but not nonhumanoids) can recover a service failure by themselves via sincere apology, restoring perceptions of warmth (Study 2A); (iii) humanoids (but not nonhumanoids) can also effectively provide explanations as a recovery tactic (Study 2B); and, importantly, (iv) human intervention can be used to mitigate dissatisfaction following inadequate recovery by a nonhumanoid robot (Study 3), supporting the notion of human-robot collaboration. Taken together, this research offers theoretical implications for robot anthropomorphism and practical implications for firms employing service robots.
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