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Abstract: Prediction of maximum load bearing capacity and crack growth for ductile materials using existing models like J-R curve approach has the problem of transferability and the use of micro-mechanical model (e.g. Gurson Tvergaard, and Needleman [Tvergaard V, Needleman A. Analysis of cup cone fracture in a round tensile bar. Acta Metall 1984;32:157–169]) are limited by the requirements of the huge computation time and large numbers of critical metallurgical parameters as input to analysis. Marie and Chapuliot [Marie S, Chapuliot S. Ductile tearing simulation based on local energy criterion. Fatigue Fract Engng Mater Struct 1998;21:215–227] of CEA, France, proposed a simple but convenient ductile crack growth model using critical fracture energy (G fr) for crack growth and J i for initiation, both of which are material parameters. They also proposed several schemes, namely, graphical and slope of modified plastic J-integral vs crack growth, J M-pl − Δa methods for the evaluation of the value of G fr from specimens as well as from components. In all these methods the role of non-crack displacement in the crack growth process was not considered. The necessary modifications due to non-crack displacement in the above methods to evaluate the values of G fr was studied and published [Acharyya S, Dhar S, Chattopadhyay J. (2003). The effect of non-crack component on Critical fracture energy on ductile material. Int J Pressure Vessels Piping 2004;81:345–353] by the authors earlier. In this paper, the modified methods and formulation have been applied to evaluate the values of G fr from experimental and FE simulated results for compact tensile (CT), three point bend (TPB) specimens and also from components like pipes and elbows. Then statistical estimation is done from these G fr values to assess whether G fr can be accepted as constant value material parameter. Finally, the mean value of G fr obtained from statistical computation is used as material constant along with crack initiation toughness parameter (J i)SZW to consider crack growth for FE simulation of load vs load-line–displacement (LLD) and load vs crack growth curves for different specimens and components. Finite element simulated results are compared with the experimental results and good matching between the two for several components are found and maximum error in prediction of maximum load is found to be within 12%. [Copyright &y& Elsevier]

Background: The DMIST (Digital Mammography Imaging Screening Trial) reported improved breast cancer detection with digital mammography compared with film mammography in selected population subgroups, but it did not assess the economic value of digital relative to film mammography screening.Objective: To evaluate the cost-effectiveness of digital mammography screening for breast cancer.Design: Validated, discrete-event simulation model.Data Sources: Data from DMIST and publicly available U.S. data.Target Population: U.S. women age 40 years or older.Time Horizon: Lifetime.Perspective: Societal and Medicare.Intervention: All-film mammography screening; all-digital mammography screening; and targeted digital mammography screening, which is age-targeted digital mammography (for women <50 years of age) and age- and density-targeted digital mammography (for women <50 years of age or women > or =50 years of age with dense breasts).Outcome Measures: Cost per quality-adjusted life-year (QALY) gained.Results Of Base-case Analysis: All-digital mammography screening cost $331,000 (95% CI, $268,000 to $403,000) per QALY gained relative to all-film mammography screening but was more costly and less effective than targeted digital mammography screening. Targeted digital mammography screening resulted in more screen-detected cases of cancer and fewer deaths from cancer than either all-film or all-digital mammography screening, with cost-effectiveness estimates ranging from $26,500 (CI, $21,000 to $33,000) per QALY gained for age-targeted digital mammography to $84,500 (CI, $75,000 to $93,000) per QALY gained for age- and density-targeted digital mammography. In the Medicare population, the cost-effectiveness of density-targeted digital mammography screening varied from a base-case estimate of $97,000 (CI, $77,000 to $131,000) to $257,000 per QALY gained (CI, $91,000 to $536,000) in the alternative-case analyses, in which the sensitivity of film mammography was increased and the sensitivity of digital mammography in women with nondense breasts was decreased.Results Of Sensitivity Analysis: Results were sensitive to the cost of digital mammography and to the prevalence of dense breasts.Limitations: Results were dependent on model assumptions and DMIST findings.Conclusion: Relative to film mammography, screening for breast cancer by using all-digital mammography is not cost-effective. Age-targeted screening with digital mammography seems cost-effective, whereas density-targeted screening strategies are more costly and of uncertain value, particularly among women age 65 years or older. [ABSTRACT FROM AUTHOR]

An inflatable Packer-Straddle Pump Assembly was used to collect depth-specific water samples from an experimental bore hole at intervals of 6 m between 28 and 58 m. Based on chemical and microbiological analyses, several redox zones in the aquifer were identified. For example, at depths of 28, 40, and 46 m, dissolved arsenic in the range of 18 to 23 µg/L and Fe(II) in the range of 1.3 to 1.6 mg/L together with the presence of iron-reducing bacterial activity suggested that reduction of ferric oxy-hydroxides was able to mobilize arsenic from sediment to groundwater. On the other hand, conditions were predominantly nitrate- reducing at 34 and 52 m where dissolved arsenic was below detection level and Fe(II) was around 0.2 mg/L. Although arsenic is present in the sediment throughout the depth of the bore hole, it was mobilized only under an iron-reducing condition. Arsenic mobilization was not observed under nitrate-reducing conditions at 34 and 52 m with a high nitrate concentration of about 4 mg/L. Nitrate from agricultural runoff accumulates in the surface water bodies and spreads in the aquifer through predominantly horizontal regional groundwater flow. Low hydraulic conductivity due to the presence of clay limits the flux of nitrate at 28, 40, and 46 m where conditions are iron reducing. [ABSTRACT FROM AUTHOR]

The concept of P-spaces was first initiated by Gillman and Henriksen in 1954 and the property of a P-space is intrinsically related with the cofinality character w0 of the real line. In this paper, we will show that the properties of countable cofinality and Cauchy completeness determine the class of P-spaces. Also, there are indeed innumerous ordered fields that are Cauchy complete and has a countable cofinality character, and a generic method to construct them is provided in Theorem 3.9. This paper contains a cardinal extension of the easier side of Theorem 3.8 and ends with an open question. [ABSTRACT FROM AUTHOR]

The effects of laser beam welding (LBW) process parameters on the characteristics of Nd:YAG laser butt welding 1.5 mm thick 2205 duplex stainless steel. Specifically, the study focuses on the depth of penetration, bead width, ultimate tensile strength (UTS) and elongation. To achieve this, a parametric study is conducted using a central composite design (CCD) with response surface methodology (RSM) to establish mathematical regression equations that identify the key process parameters and their effects on the responses. The investigations showed that the size of the meltpool at the fusion zone (FZ) increases as the laser power increases. This leads to the formation of wider and deeper weld beads, ultimately leading to stronger and more flexible joints. Similarly, pulse width and scanning speed have a significant impact on the weld bead geometry, UTS, and elongation. It is observed that the FZ is free of any visible cracks, voids, or porosity. The LBW process parameters have been optimized to reduce operating costs by lowering the line energy, without compromising the welding quality. The optimal UTS value for the welded joint is around 865 MPa, which is almost equivalent to 99% of the UTS of the 2205 duplex stainless steel base material (BM). To obtain high-quality welded joints, it is recommended to use a laser power ranging from 423 to 425 W, scanning speed of 5.3 mm/s and pulse width of 5.4 ms. [ABSTRACT FROM AUTHOR]

• Theoretical calculations (optimization) are carried out for the total front contact losses (viz. optical and electrical) of commercially available patterns solar cell. • The levelized cost of energy (LCOE) due to Silver (Ag) paste has also been estimated for production of 10 MW power. • The effect of increasing number of busbars on solar cell performance is analyzed here. The EM field distribution due to incident photon flux is also shown here using COMSOL Multiphysics simulation software. Solar cell performance is highly dependent upon the front contact grid design for minimizing the power losses due to shading (optical loss) and for proper collection of the photo-generated charge carriers (electrical loss). In this paper, theoretical calculations (optimization) have been carried out for the total power losses (viz. optical and electrical) due to different front grid multi-busbar patterns similar to the ones currently used in industrial production. Busbar width and finger spacing, the two important design parameters of solar cell with standard busbar structure, are optimized for multi busbar systems. Role of interlinks between the fingers to reduce the power loss has also been studied. The effect of each optimized grid design on the component in the levelized cost of electricity (LCOE) due to Silver (Ag) requirement has been estimated for a 10 MW power system with a 25 years lifespan. The study of EM field distribution due to incident photon flux shows that increasing the number of busbars can generate carriers within the shaded areas under the busbars. [ABSTRACT FROM AUTHOR]