Ductile Fracture Simulation of Full-scale Circumferential Cracked Pipes: (II) Stainless Steel

AbstractThis paper reports ductile fracture simulation of full-scale circumferentially cracked pipes using finite element (FE) damage analysis. In the structural integrity, without experimental investigations or with few ones, it is not an easy task to properly evaluate the crack initiation and crack propagation of large-scale components with a crack-like defect. Unfortunately, from an economic perspective, performing experiments of large-scale components would be consequently unfavorable. For these reasons, ductile fracture simulation using FE damage analysis to predict crack behavior is one efficient way to replace the test procedures. In order to simulate ductile tearing of large-scale cracked pipes, element-size-dependent critical damage model based on the stress-modified fracture strain model is proposed. To evaluate fracture behavior of full-scale cracked pipes, tensile and C(T) specimens are calibrated by FE analysis technique. Tensile properties and fracture toughness of stainless steel at 288oC are taken from Battelle Pipe Fracture Encyclopedia. After calibrations, simulated results of the full-scale pipes with a circumferential crack are compared with test data to validate the proposed method

The Economics of All-You-Can-Read Pricing: Tariff Choice, Contract Renewal, and Switching for E-Book Purchases

E-book markets are currently moving through a period of disequilibrium as new pricing structures (i.e., flat-fee subscriptions) are rapidly embraced by major vendors. On the basis of a novel dataset, we investigate how the availability of “all-you-can-read” pricing programs influences consumers’ tariff choice, contract renewal, and switching behaviors. Consistent with the rational choice framework, the findings suggest that most e-book consumers significantly gain from subscription-based tariffs. However, we also find some other intriguing results. Among the three subscription designs examined, the 1-week plan affords consumers more economic benefits than do 1-day or 1-month programs. The economic gains derived from subscription-based tariffs diminish as consumers renew their subscriptions under the same contract duration. Consumers who switch to other plans also suffer from reduced savings. Finally, iOS users are more inclined to select subscription models than are Android users because of the absence of in-app purchase functionalities for the former

The sniffing position facilitated easier light wand guided endotracheal intubation compared with the neutral position with chin-lift

Background Traditionally, the patient's head is placed in a neutral position with a chin-lift to facilitate light wand guided endotracheal intubation. However, our study found that the sniffing position was more effective. In this study, we aimed to compare the two positions of light wand guided endotracheal intubation. Methods Sixty adult patients were included in the study, after obtaining informed consent, and were randomly assigned to one of two groups: a control group in a neutral position with a chin-lift (group C, n = 30) and a sniffing position group (group S, n = 30). In group C, the anesthesiologist inserted a light wand after lifting the patient's mandible using the thumb of their non-dominant hand inside the patient's mouth. In group S, a light wand was inserted after the patient's head was flexed with the neck extended. We assessed variables such as light-search time, number of intubation attempts, time to achieve intubation, and side effects including blood tinge on the endotracheal tube, hoarseness, sore throat, and anesthesiologist satisfaction. Results The light-search and intubation times were shorter in group S than in group C. The incidence of blood tinge on the endotracheal tube was higher in group C than in group S. Anesthesiologist satisfaction was higher in group S than in group C. Conclusions The sniffing position was more effective in facilitating light wand guided endotracheal intubation than the neutral position with a chin-lift

PVP2010-25373 EFFECT OF CREEP MISMATCH FACTOR ON STRESS REDISTRIBUTION IN WELDED BRANCH PIPES

ABSTRACT This paper describe steady state stress distribution into the weld metal of welded branch components using detailed three dimensional elastic creep finite element analyses. In order to show the effect of the loading mode, this research is carried out under various loading conditions such as internal pressure, inplane bending to the branch pipe and out-of-plane bending to branch pipe. Also, to generalize the unique aspect, three geometries of branch components including welded large bore branch, medium bore branch, and trunnion are considered. It is a well-known fact that the creep strain rate of welds material is faster than that of parent material. Therefore, the creep exponent and constants for the parent and weld metal are systematically varied to analyze under-matching, evenmatching and over-matching conditions in creep. It can be shown that mismatch effect can be quantified as mismatch factor with specific characteristics

The Fit between Client IT Capability and Vendor Competence and Its Impact on Outsourcing Success

This study investigates the impact of client firm’s IT capability, vendor firm’s competence and their fit on the outsourcing success. In theory building, by concretizing the concepts of IT capability and competence based on the resource-based view, the importance of fit between the client’s IT capability and the vendor’s competence is emphasized. We then hypothesize that both factors are stronger together than the individual impact of either the client’s IT capability or the vendor’s competence. For validation, 267 client-vendor-matched-pair data were collected. To avoid potential imbalance caused by the bilateral perspective, an exploratory approach, all-possible-subsets-regression method was adopted. The results reveal that the vendor’s competence is the most significant factor in outsourcing success, but interestingly, the fit between vendor competence and the client’s IT capability is the second most important. The client’s IT capability also has a positive impact on outsourcing success but with the smallest explanation power

Analysis of Laser ARPES from Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta} in superconductive state: angle resolved self-energy and fluctuation spectrum

We analyze the ultra high resolution laser angle resolved photo-emission spectroscopy (ARPES) intensity from the slightly underdoped Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ in the superconductive (SC) state. The momentum distribution curves (MDC) were fitted at each energy \w employing the SC Green's function along several cuts perpendicular to the Fermi surface with the tilt angle $\theta$ with respect to the nodal cut. The clear observation of particle-hole mixing was utilized such that the complex self-energy as a function of $\omega$ is directly obtained from the fitting. The obtained angle resolved self-energy is then used to deduce the Eliashberg function \alpha^2 F^{(+)}(\th,\w) in the diagonal channel by inverting the d-wave Eliashberg equation using the maximum entropy method. Besides a broad featureless spectrum up to the cutoff energy $\omega_c$, the deduced $\alpha^2 F$ exhibits two peaks around 0.05 eV and 0.015 eV. The former and the broad feature are already present in the normal state, while the latter emerges only below $T_c$. Both peaks become enhanced as $T$ is lowered or the angle $\th$ moves away from the nodal direction. The implication of these findings are discussed.Comment: 7 pages, 5 figures, summited to PR

Development of Pd Alloy Hydrogen Separation Membranes with Dense/Porous Hybrid Structure for High Hydrogen Perm-Selectivity

For the commercial applications of hydrogen separation membranes, both high hydrogen selectivity and permeability (i.e., perm-selectivity) are required. However, it has been difficult to fabricate thin, dense Pd alloy composite membranes on porous metal support that have a pore-free surface and an open structure at the interface between the Pd alloy films and the metal support in order to obtain the required properties simultaneously. In this study, we fabricated Pd alloy hydrogen separation membranes with dense/porous hybrid structure for high hydrogen perm-selectivity. The hydrogen selectivity of this membrane increased owing to the dense and pore-free microstructure of the membrane surface. The hydrogen permeation flux also was remarkably improved by the formation of an open microstructure with numerous open voids at the interface and by an effective reduction in the membrane thickness as a result of the porous structure formed within the Pd alloy films