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Immune checkpoint inhibitors have demonstrated significant survival benefits in treating many types of cancers. However, their immune-related adverse events (irAEs) have not been systematically evaluated across cancer types in large-scale real-world populations. To address this gap, we conducted real-world data analyses using nationwide insurance claims data with 85.97 million enrollees across 8 years. We identified a significantly increased risk of developing irAEs among patients receiving immunotherapy agents in all seven cancer types commonly treated with immune checkpoint inhibitors. By six months after treatment initialization, those receiving immunotherapy were 1.50–4.00 times (95% CI, lower bound from 1.15 to 2.16, upper bound from 1.69 to 20.36) more likely to develop irAEs in the first 6 months of treatment, compared to matched chemotherapy or targeted therapy groups, with a total of 92,858 patients. The risk of developing irAEs among patients using nivolumab is higher compared to those using pembrolizumab. These results confirmed the need for clinicians to assess irAEs among cancer patients undergoing immunotherapy as part of management. Our methods are extensible to characterizing the effectiveness and adverse effects of novel treatments in large populations in an efficient and economical fashion. [ABSTRACT FROM AUTHOR]

For epidemics control and prevention, timely insights of potential hot spots are invaluable. Alternative to traditional epidemic surveillance, which often lags behind real time by weeks, big data from the Internet provide important information of the current epidemic trends. Here we present a methodology, ARGOX (Augmented Regression with GOogle data CROSS space), for accurate real-time tracking of state-level influenza epidemics in the United States. ARGOX combines Internet search data at the national, regional and state levels with traditional influenza surveillance data from the Centers for Disease Control and Prevention, and accounts for both the spatial correlation structure of state-level influenza activities and the evolution of people's Internet search pattern. ARGOX achieves on average 28% error reduction over the best alternative for real-time state-level influenza estimation for 2014 to 2020. ARGOX is robust and reliable and can be potentially applied to track county- and city-level influenza activity and other infectious diseases. [ABSTRACT FROM AUTHOR]

In this paper, we study the non-magnetic insulator state near Mott transition of 2D π-flux Hubbard model on square lattice and find that such non-magnetic insulator state is quantum spin liquid state with nodal fermionic excitations - nodal spin liquid (NSL). When there exists small easy-plane anisotropic energy, the ground state becomes Z topological spin liquid (TSL) with full gapped excitations. The U(1) × U(1) mutual-Chern-Simons (MCS) theory is obtained to describe the low energy physics of NSL and TSL. [ABSTRACT FROM AUTHOR]

Ternary Mg-Al-Sr alloys are the base of a few new creep-resistant, lightweight Mg alloys for automobiles. Hot tearing of Mg-Al-Sr alloys was studied by constrained rod casting (CRC) in a steel mold equipped with a load cell and a thermocouple. The alloys investigated included, in order of decreasing hot tearing susceptibility, Mg-4Al-1.5Sr, Mg-6Al-1.5Sr, Mg-8Al-1.5Sr, and Mg-8Al-3Sr. Two different molds were used, one for 8.7-mm-diameter rods and the other 7.9 mm. The cooling rate was varied by varying mold preheating from 523 K (250 °C) to 658 K (385 °C) and mold insulation. The load curve showed a clear peak when hot tearing occurred in all but Mg-8Al-3Sr due to its high resistance to hot tearing. From the peak and the cooling curve, the temperature at which hot tearing occurred was determined and found to decrease with increasing Al content from 4 to 8 pct. For a specific alloy, the hot tearing onset temperature did not change significantly with the rod diameter or mold preheating, at least within the experimental conditions used. The Scheil solidification model was used to estimate the fraction solid at the onset of hot tearing. It was found that hot tearing occurred near the end of primary solidification L → α (Mg) and that the fraction solid at which hot tearing occurred decreased with increasing Al content. The validity of the Scheil model was discussed. [ABSTRACT FROM AUTHOR]

The susceptibility of Mg-Al-Sr alloys to hot tearing during permanent mold casting was investigated using constrained rod casting (CRC) in a steel mold. The alloys included Mg- xAl-1.5Sr and Mg- xAl-3Sr, where x = 4, 6, or 8 wt pct. The hot-tearing susceptibility (HTS) was determined based on the widths and locations of the cracks in the rods. With the Mg- xAl-1.5 Sr alloys, the HTS decreased significantly with increasing Al content. With the Mg- xAl-3Sr alloys, the trend was similar but not as significant. At the same Al content, the HTS was significantly lower at 3 wt pct Sr than at 1.5 wt pct Sr. To help understand the HTS of these alloys, the solidification path and phase fractions were calculated for each alloy. The HTS was found to increase with increasing fraction solid at the end of primary solidification. [ABSTRACT FROM AUTHOR]

It is known that DNA-binding proteins can slide along the DNA helix while searching for specific binding sites, but their path of motion remains obscure. Do these proteins undergo simple one-dimensional (1D) translational diffusion, or do they rotate to maintain a specific orientation with respect to the DNA helix? We measured 1D diffusion constants as a function of protein size while maintaining the DNA-protein interface. Using bootstrap analysis of single-molecule diffusion data, we compared the results to theoretical predictions for pure translational motion and rotation-coupled sliding along the DNA. The data indicate that DNA-binding proteins undergo rotation-coupled sliding along the DNA helix and can be described by a model of diffusion along the DNA helix on a rugged free-energy landscape. A similar analysis including the 1D diffusion constants of eight proteins of varying size shows that rotation-coupled sliding is a general phenomenon. The average free-energy barrier for sliding along the DNA was 1.1 ± 0.2 kBT. Such small barriers facilitate rapid search for binding sites. [ABSTRACT FROM AUTHOR]

Advances in nanotechnology enable scientists for the first time to study biological processes on a nanoscale molecule-by-molecule basis. They also raise challenges and opportunities for statisticians and applied probabilists. To exemplify the stochastic inference and modeling problems in the field, this paper discusses a few selected cases, ranging from likelihood inference, Bayesian data augmentation, and semi- and non-parametric inference of nanometric biochemical systems to the utilization of stochastic integro-differential equations and stochastic networks to model single-molecule biophysical processes. We discuss the statistical and probabilistic issues as well as the biophysical motivation and physical meaning behind the problems, emphasizing the analysis and modeling of real experimental data. [ABSTRACT FROM AUTHOR]

The thermodynamic description of the Mg-Al-Ca-Sr quaternary system in the magnesium-rich region was developed on the basis of the authors’ previous work on the key constituent ternaries, such as Mg-Al-Ca and Mg-Al-Sr systems. Using this description coupled with the Scheil model, the calculated solidification paths of several Mg-Al-Sr ternary alloys and Mg-Al-Ca-Sr quaternary alloys are in good accordance with experimental results from directional solidification as well as published results from cast alloys. These results validate the reliability of the present thermodynamic description of the Mg-Al-Ca-Sr quaternary system in the magnesium-rich region. More importantly, the predicative nature of the calculation either using only thermodynamic data or coupled with the kinetic model makes it possible to exploit new alloy compositions where experimental investigation has not been attempted. [ABSTRACT FROM AUTHOR]

Mg–6Zn/1.5%SiC nanocomposites were successfully fabricated by ultrasonic cavitation-based dispersion of SiC nanoparticles in Mg–6Zn alloy melt. As compared to un-reinforced Mg–6Zn alloy matrix, the mechanical properties of the nanocomposites including the tensile strength and yield strength of the Mg–6Zn/1.5%SiC nanocomposites were significantly higher; the good ductility of Mg–6Zn alloy matrix was retained. Nanoparticles were dispersed well though there were still some SiC microclusters in the microstructure. Also, the grain size of Mg–6Zn alloy was reduced considerably by the addition of 1.5%SiC nanoparticles. [ABSTRACT FROM AUTHOR]

Copyright of Materials & Structures is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ternary Mg-Al-Ca alloys are the base of a few new creep-resistant, lightweight Mg alloys for automobiles. Hot tearing in Mg-xAl-yCa alloys was studied, including Mg-4Al-0.5Ca, Mg-4Al-1.5Ca, Mg-4Al-2.5Ca, Mg-4Al-3.5Ca, Mg-5A1-2.5Ca, and Mg-6Al-2.5Ca, by constrained rod casting (CRC) in a steel mold--with a movable pouring cup to keep solidification therein from interfering with the rising tension in the rods. The hot tearing susceptibility, based on measured crack widths and crack locations, decreased significantly with increasing Ca content (y) but did not change much with the A1 content (x). An instrumented CRC with a steel mold was developed to detect the onset of hot tearing by monitoring the tension in the rod during casting and the temperature near the cracking site. It was further improved by reducing the rod diameter to detect hot tearing earlier, at a higher temperature, and with a clear peak in the load curve. To further understand the hot tearing susceptibility of these alloys, the secondary phases, eutectic content, solidification path, and freezing range were examined. Alloy Mg-4Al-0.5Ca had the widest freezing range and the lowest eutectic content and was most susceptible to hot tearing, while alloys Mg-4Al-3.5Ca and Mg-6Al-2.5Ca were the opposite. Mg-4Al-0.5Ca had the widest freezing range (183 °C) because its solidification path led to the formation of Mg17Al12 from the liquid at a very low temperature (440 °C). The application of the results to die casting was discussed. [ABSTRACT FROM AUTHOR]

Enzymes are biological catalysts vital to life processes and have attracted century-long investigation. The classic Michaelis-Menten mechanism provides a highly satisfactory description of catalytic activities for large ensembles of enzyme molecules. Here we tested the Michaelis-Menten equation at the single-molecule level. We monitored long time traces of enzymatic turnovers for individual β-galactosidase molecules by detecting one fluorescent product at a time. A molecular memory phenomenon arises at high substrate concentrations, characterized by clusters of turnover events separated by periods of low activity. Such memory lasts for decades of timescales ranging from milliseconds to seconds owing to the presence of interconverting conformers with broadly distributed lifetimes. We proved that the Michaelis-Menten equation still holds even for a fluctuating single enzyme, but bears a different microscopic interpretation. [ABSTRACT FROM AUTHOR]

We show that lightly doped holes will be self-trapped in an antiferromagnetic spin background at low-temperature, resulting in spontaneous translational symmetry breaking. The underlying Mott physics is responsible for such novel self-localization of charge carriers. Interesting transport and dielectric properties are found as the consequences, including large doping-dependent thermopower and dielectric constant, low-temperature variable-range-hopping resistivity, as well as high-temperature strange-metal-like resistivity, which are consistent with experimental measurements in the high-Tc cuprates. Disorder and impurities only play a minor and assistant role here. [ABSTRACT FROM AUTHOR]

The importance of the microstructural parameters in rock mechanical behavior has been investigated by several authors. Moreover, the Weibull statistical model has been used to characterize the heterogeneity of several materials on the basis of the concept that the microscopic defects within the material determine their mechanical strength. The modeling of different rocks is a topic that is fundamental for the prediction of rock fragmentation. In this article, the analysis of rock microstructure is performed using the microstructural modeling approach, which consists of the simplification, quantification, and modeling of the main properties of rock microstructure. The grain size, grain shape, and microcracks are modeled by means of statistical density functions, namely, Cauchy, chi-squared, exponential, extreme value, gamma, Laplace, normal, uniform, and Weibull. It is found that the Weibull distribution is the most appropriate statistical model of the grain size and grain shape, when compared with the other eight statistical models. Regarding microcracks, the results show that the gamma distribution is the most appropriate model. The Weibull and gamma distributions are then used to analyze the heterogeneity of the microstructure. This is done by comparison of the statistical models of each microstructural property evaluated in several thin sections of the same rock. It is found that with respect to grain size and grain shape, the rock is homogeneous, while the size distribution of the microcracks shows a clear trend toward less homogeneity. The microstructural modeling approach is important for modeling, characterizing, and analyzing the microstructure of rock material. Among other applications, it can be used to explain differences in the mechanical behavior obtained in testing several specimens. [ABSTRACT FROM AUTHOR]

To evaluate the influence of the petrographic variables on the quality of coarse aggregates consisting of granitoid (granite to tonalite) rocks, 17 samples selected from the Swedish part of the Baltic shield have been studied concerning their petrographic properties, for example, mineral composition, grain size, grain boundaries, and the frequency of micro-cracks. All of the samples selected also have been studied in mechanical tests used to evaluate the quality of aggregates in Sweden. The quality has been determined by means of flakiness, impact value, abrasion value I, and abrasion value II. An analysis of the influence of the mineral composition and textural properties on the aggregate quality has been performed using statistical correlation and linear models. The results indicate that an increasing content of feldspar negatively influences the strength against impact, while an increasing content of mica (tested to 35 vol. %) combined with a diminishing grain size and more irregular grain boundaries has a positive influence on the resistance of granitoids to mechanical impact. Abrasion value II seems to be mainly influenced negatively by an increasing frequency of micro-cracks. The practical implementation of the results is suggested. [ABSTRACT FROM AUTHOR]

This paper concerns the cubic smoothing spline approach to nonparametric regression. After first deriving sharp asymptotic formulas for the eigenvalues of the smoothing matrix, the paper uses these formulas to investigate the efficiency of different selection criteria for choosing the smoothing parameter. Special attention is paid to the generalized maximum likelihood (GML), C[subp] and extended exponential (EE) criteria and their marginal Bayesian interpretation. It is shown that (a) when the Bayesian model that motivates GML is true, using C[subp] to estimate the smoothing parameter would result in a loss of efficiency with a factor of 10/3, proving and strengthening a conjecture proposed in Stein (1990); (b) when the data indeed come from the C[subp] density, using GML would result in a loss of efficiency of ∞; (c) the loss of efficiency of the EE criterion is at most 1.543 when the data are sampled from its consistent density family. The paper not only studies equally spaced observations (the setting of Stein, 1990), but also investigates general sampling scheme of the design points, and shows that the efficiency results remain the same in both cases. [ABSTRACT FROM AUTHOR]

This paper presents the testing methods used and the results obtained in an investigation of the cutter forces on a Boretec DS 1.6 boring machine during field boring in Äspö Hard Rock Laboratory. Two button cutters, one front cutter and one gauge cutter, were used in the field measurements. A total of 6 strain gauges were bonded on the shaft of each cutter. And each group of two gauges was used to measure a one-orthogonal cutter force component, i.e. the normal force, tangential force, and side force, respectively. In order to measure the cutter forces successfully, a telemetry system composed of a transmitter and a receiver was employed to transfer the signals from the strain gauges to a computer. A three-direction-loading system was employed in the laboratory calibration so as to solve the force-coupling problem appearing in the cutter force measurements. Correspondingly, a mathematical treatment of the force-coupling problem was performed. Then, by means of the established testing system, which was proved successful in the laboratory, the normal force, tangential force, and side force of the two button cutters on the boring machine were measured in the field. In addition, the penetration rate, thrust, and rotation speed of the boring machine were also recorded in the field. The results show the following. (1) A force-coupling phenomenon really exists and it should be considered. (2) All three directional force components always show quite a high peak value every few seconds. (3) The cutter forces of the front cutter are always much larger than the respective cutter forces of the gauge cutter. Moreover, as expected, the normal force of each cutter is much larger than the tangential force and side force of the cutter in question. [ABSTRACT FROM AUTHOR]

By means of spectral analysis, the measured normal forces, tangential forces, and side forces acting on two button cutters on the boring machine in Äspö Hard Rock Laboratory were analysed and the basic characteristics of the cutter forces were determined. After the measurements of the cutter forces, some rock core samples were taken from the bottom and the wall of the test borehole. These samples were cut, polished, and examined by means of a Scanning Electron Microscope (SEM). The lengths of the major cracks in the rock samples were measured, and a relation between the length of the median cracks and the relevant cutter forces was investigated. [ABSTRACT FROM AUTHOR]

The Compressive strength, porosity and pore size distribution of high performance metakaolin (MK) concrete were investigated. Concretes containing 0.5%, 10% and 20% metakaolin were prepared at a water/cementitious material ratio (W/C) of 0.30. In parallel, concrete mixtures with the replacement of cement by 20% fly ash or 5 and 10% silica fume were prepared for comparison. The specimens were cured in water at 27°C for 3 to 90 days. The results show that at the early age of curing (3 days and 7 days), metakaolin replacements increase the compressive strength but silica fume replacement slightly reduces the compressive strength. At the age of and after 28 days, the compressive strength of the concrete with metakaolin and silica fume replacement increases. A strong reduction in the total porosity and average pore diameter were observed in the concrete with MK 20% and 10% in the first 7 days. [ABSTRACT FROM AUTHOR]

Abstract. The valuation theory for American Contingent Claims, due to Bensoussan (1984) and Karatzas (1988), is extended to deal with constraints on portfolio choice, including incomplete markets and borrowing/short-selling constraints, or with different interest rates for borrowing and lending. In the unconstrained case, the classical theory provides a single arbitrage-free price u[sub 0]; this is expressed as the supremum, over all stopping times, of the claim's expected discounted value under the equivalent martingale measure. In the presence of constraints, {u[sub 0]} is replaced by an entire interval [h[sub low], h[sub up]] of arbitrage-free prices, with endpoints characterized as h[sub low] = inf[sub upsilon is an element of L], h[sub up] = sup[sub upsilon is an element of L] u[sub upsilon]. Here u[sub upsilon] is the analogue of u[sub 0], the arbitrage-free price with unconstrained portfolios, in an auxiliary market model M[sub upsilon]; and the family {M[sub upsilon]}[sub upsilon is an element of L] is suitably chosen, to contain the original model and to reflect the constraints on portfolios. For several such constraints, explicit computations of the endpoints are carried out in the case of the American call-option. The analysis involves novel results in martingale theory (including simultaneous Doob-Meyer decompositions), optimal stopping and stochastic control problems, stochastic games, and uses tools from convex analysis. Key words: Contingent claims, hedging, pricing, arbitrage, constrained markets, incomplete markets, different interest rates, Black-Scholes formula, optimal stopping, free boundary, stochastic control, stochastic games, equivalent martingale measures, simultaneous Doob-Meyer decompositions. JEL classification: Primary G13; Secondary D52, C60. [ABSTRACT FROM AUTHOR]

Crystal growth, by the recently developed Ohno continuous casting (O.C.C) process, was studied using pure tin. The effects of four process variables on crystal growth were studied: these were the mold exit temperature, the casting speed, the melt temperature, and the cooling condition. Small single crystals of 6.4 mm diameter were produced both by repeated necking and by using single crystal seeds. Excellent surface quality was obtained in these small-diameter crystals. [ABSTRACT FROM AUTHOR]

The grain structure of the weld metal can significantly affect its resistance to solidification cracking during welding and its mechanical properties after welding. An experimental study was conducted to investigate the effect of two basic welding parameters, i.e., the heat input and the welding speed, on the grain structure of aluminum-alloy welds. Gas-tungsten arc welding was performed under various heat inputs and welding speeds, with thermal measurements in the weld pool being carried out during welding and the amounts and nuclei of equiaxed grains in the resultant welds being examined using optical and electron microscopy. The experimentally measured G/R ratios and the clearly revealed heterogeneous nuclei together demonstrated the thermodynamic effect of the heat input and welding speed on the weld metal grain structure. [ABSTRACT FROM AUTHOR]

Computer simulation for three-dimensional convection in moving arc weld pools was described, with three distinct driving forces for flow considered - the electromagnetic force, the buoyancy force, and the surface tension gradient on the pool surface. Formulation of the electromagnetic force in the weld pool was presented. The calculated and experimentally observed fusion boundaries were compared. The arc efficiency and spatial distributions of the current density and power density used in the calculations were based on experimentally measured results, in order to verify the model. The effects of the electromagnetic and surface tension forces were discussed. [ABSTRACT FROM AUTHOR]

Computer simulation was carried out to describe three-dimensional convection in laser melted pools, i.e., for the case where the workpiece is moving with respect to the laser beam. Two different types of driving forces for flow were considered in the model, i.e., the buoyancy force and the surface tension gradient at the pool surface. Laser surface melting of 6063 aluminum alloy was carried out using a continuous-wave CO laser, and the power delivered to the workpiece was measured calorimetrically. The calculated and observed fusion boundaries were compared and very good agreement was obtained. Finally, the effect of the surface tension temperature coefficient δγ/δT on the convection pattern and penetration of laser melted pools was demonstrated with the model. [ABSTRACT FROM AUTHOR]

A new mechanism for reducing weld solidification cracking was proposed, based on the concept of the crack path and resistance to crack propagation, and its effectiveness was verified in magnetically oscillated GTA welds of a rather crack susceptible material 2014 aluminum alloy. This mechanism, i.e., alternating grain orientation, was most pronounced in welds made with transverse arc oscillation of low frequency and high amplitude, and solidification cracking was dramatically reduced in these welds. The effect of the arc oscillation pattern, amplitude, and frequency on the formation of alternating columnar grains and the reduction of solidification cracking in GTA welds of 2014 aluminum alloy was examined and explained. The present study demonstrated for the first time that columnar grains can, in fact, be very effective in reducing solidification cracking, provided that they are oriented favorably. [ABSTRACT FROM AUTHOR]

The effect of arc oscillation on grain structure and solidification cracking in GTA welds of 5052 aluminum alloy was investigated using a four-pole magnetic arc oscillator and a modified fish-bone crack test. Two different mechanisms of crack reduction were identified: one in the low frequency range of arc oscillation and the other in the high frequency range. The former was the alteration of the orientation of columnar grains, while the latter was grain refining. Neither mechanism was operative in the intermediate frequency range and solidification cracking was severe, especially when the amplitude of arc oscillation was small. Alteration of grain orientation was obtained in welds made with transverse and circular arc oscillations, but not longitudinal arc oscillation. Grain refining, on the other hand, was achieved in welds made with all three types of arc oscillation patterns. The differences between the response of alloy 5052 to arc oscillation and that of alloy 2014 observed previously were discussed. [ABSTRACT FROM AUTHOR]

A combined theoretical and experimental study of steady-state fluid flow, heat flow and segregation in axi-symmetric ingot production is presented, with specific applications in continuous casting and ESR. The fluid flow-segregation model involves the coupling of convective heat and fluid flow in the fully liquid metal pool ahead of the liquidus isotherm to the interdendritic fluid flow responsible for macrosegregation in the 'mushy' zone of ingots solidifying under axi-symmetric conditions. Experiments on low-temperature Sn-Pb alloys verify the solidification model. [ABSTRACT FROM AUTHOR]

Rapid melting and solidification of a semi-infinite substrate subjected to a high intensity heat flux over a circular region on its bounding surface moving with a constant velocity is considered. General expressions are developed for the coefficients in the finite difference equation governing the heat transfer in moving orthogonal curvilinear coordinate systems. These expressions are reduced to their specific forms in terms of dimensionless nodal temperature and enthalpy for a moving oblate spheroidal coordinate system. Quasisteady state conditions are assumed and the thermal properties of the substrate in the liquid and solid phase are considered constant and equal. It is also assumed that the substrate melts and solidifies at a single temperature. Temperature distributions in the molten region and the adjacent heat affected zone are computed along with the liquid-solid interface shape, its velocity and other important solidification variables. Both uniform and Gaussian heat flux distributions within the circular region are considered. The results are presented in their most general form-in terms of dimensionless numbers when possible. Specific criteria for the melting of the substrate are established. It is shown that the three variables, absorbed heat flux q, the radius of the circular region a and the velocity of the moving flux U, could be combined into two independent variables. That is, the dimensionless temperature distribution in the metal pool and the solid substrate remain the same as long as the products qa and Ua or U/q are kept constant. The effect of these variables on cooling rate in the liquid and the ratio of temperature gradient to growth rate at the solid-liquid interface are discussed using an aluminum substrate as an example. [ABSTRACT FROM AUTHOR]

A general two-dimensional computer heat flow model is developed in an oblate spheroidal coordinate system for rapid melting and subsequent solidification of the surface of a semiinfinite solid subjected to a high intensity heat flux over a circular region on its bounding surface. Generalized numerical solutions are presented for an aluminum substrate subjected to both uniform and Gaussian heat flux distributions. Temperature distributions, melt depth and geometry, and melting and solidification interface velocities are calculated as a function of applied heat flux, radius of the circular region, and time. It is shown that the important melting and solidification parameters are a function of the product of the absorbed heat flux, q, and the radius of the circular region, a. General trends established show that melt depth perpendicular to the surface is inversely proportional to the absorbed heat flux for a given temperature at the center of the circular region. Dimensionless temperature distributions and the ratio of liquid-solid interface velocity to absorbed heat flux, R/q, as a function of dimensionless melt depth remain the same if the product qa is kept constant, while q and a are varied. For a given total power absorbed melting and solidification parameters are compared for uniform and Gaussian heat flux distributions. For a given temperature at the center of the circular region both melt depth and width are smaller for the Gaussian distribution while temperature gradients and interface velocities are larger. [ABSTRACT FROM AUTHOR]

A theoretical and experimental study of heat flow and solidification during the autogenous GTA welding of aluminum plates was carried out. The theoretical part of the study involves the development of a computer model which describes three-dimensional heat flow during welding. The model, though valid for any plate thickness, is particularly useful for moderately thick plates since both full- and partial-penetration welds can be considered. The experimental part of the study, on the other hand, involves the measurement of the thermal response of the workpiece during welding, and the examination of the configuration, grain structure, and subgrain structure of the fusion zone. The experimental results were compared with the calculated ones and the agreement was very good. With the help of the computer model, the effects of welding parameters on weld penetration in moderately thick plates were discussed. These parameters are the heat input per unit length of the weld, the thickness of the workpiece, the preheating of the workpiece, and the power-density distribution of the heat source. [ABSTRACT FROM AUTHOR]

The heat flow model previously developed for a pure metal is extended to the solidification of an alloy over a range of temperatures. The eq11Ations are then applied to rapid surface melting and solidification of an alloy substrate. The substrate is subjected to a pulse of stationary high intensity heat flux over a circular region on its bounding surface. The finite difference form of the heat transfer eq11Ation is written in terM of dimensionless nodal temperature and enthalpy in an oblate spheroidal coordinate system. A numerical solution technique is developed for an alloy which precipitates a eutectic at the end of solidification. Generalized solutions are presented for an Al-4.5 wt pct Cu alloy subjected to a uniform heat flux distribution over the circular region. Dimensionless temperature distributions, size and location of the 'mushy' zone, and average cooling rate during solidification are calculated as a function of the product of absorbed heat flux, q, the radius of the circular region, a, and time. General trends established show that for a given product of qa all isotherM are located at the same dimensionless distance for identical Fourier numbers. The results show that loss of superheat and shallower temperature gradients during solidification result in significantly larger 'mushy' zone sizes than during melting. Furthermore, for a given set of process parameters, the average cooling rate increases with distance solidified from the bottom to the top of the melt pool. [ABSTRACT FROM AUTHOR]

Weld solidification structure of three different types of stainless steel, i.e., 310 austenitic, 309 and 304 semiaustenitic, and 430 ferritic, was investigated. Welds of each material were made without any quenching, with water quenching, and with liquid-tin quenching during welding. The weld micro-structure obtained was explained with the help of the pseudobinary phase diagrams for Fe-Cr-Ni and Fe-Cr-C systems. It was found that, due to the postsolidification 5 → γ phase transformation in 309 and 304 stainless steels and the rapid homogenization of microsegregation in 430 stainless steel, their weld solidification structure could not be observed unless quenched from the solidification range with liquid tin. Moreover, the formation of acicular austenite, and hence, martensite, at the grain boundaries of 430 stainless steel welds was eliminated completely when quenched with liquid tin. The weld solidification structure of 310 stainless steel, on the other hand, was essentially unaffected by quenching. Based upon the observations made, the weld microstructure of these stainless steels was summarized. The effect of cooling rate on the formation of primary austenite in 309 stainless steel welds was discussed. Finally, a simple method for determining the relationship between the secondary dendrite arm spacing and the solidification time, based on welding speeds and weld pool configurations, was suggested. [ABSTRACT FROM AUTHOR]

Thermodynamic data of the α-AuZn alloys recently reported in the literature are found to follow closely the sub-regular solution model. Values of the two parameters for this model are found to increase linearly with temperature. Using the α-phase data, the established (α + β′) phase boundaries, the thermodynamic activities of Zn in the β′-phase, the theoretical equations of Chang and co-workers for ordered phases and the calorimetric value of the stoichiometric alloy, the thermodynamic properties of β-AuZn alloys are obtained. It is found that the thermal entropy of the β-AuZn phase is essentially independent of composition, verifying one of the assumptions made in the theoretical equations of Chang and co-workers. The large discrepancies between the three sets of experimental data for β′-AuZn phases are discussed and best consistent results are reported. [ABSTRACT FROM AUTHOR]

The thermodynamic activity, partial molar entropy and partial molar enthalpy of zinc have been calculated based on the measurement of partial pressure of zinc above eleven β'-NiZn alloys exhibiting the CsCl-type of structure over the temperature interval 1042 to 1159 K, using the dew-point method. Good correlations are found between theory and experiment for all three partial quantities. Furthermore, from these results and the recently reported data on the f.c.c. terminal solid solutions, the corresponding partial quantities of nickel in β'-NiZn alloys are computed as well as the integral quantities. It is found that the thermal entropy of this phase remains constant with composition, an assumption used by Chang and co-workers in deriving the theoretical equations to account for the compositional variations of the thermodynamic properties for this type of ordered phase. A similar analysis is also made for the thermodynamic properties of the low-tempe rature form of the equi-atomic phase exhibiting the face-centered tetragonal superlattice structure. [ABSTRACT FROM AUTHOR]

Copyright of Archives of Orthopaedic & Traumatic Surgery / Archiv für Orthopädie, Mechanotherapie und Unfallchirurgie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Accurate, high-resolution tracking of influenza epidemics at the regional level helps public health agencies make informed and proactive decisions, especially in the face of outbreaks. Internet users' online searches offer great potential for the regional tracking of influenza. However, due to the complex data structure and reduced quality of Internet data at the regional level, few established methods provide satisfactory performance. In this article, we propose a novel method named ARGO2 (2-step Augmented Regression with GOogle data) that efficiently combines publicly available Google search data at different resolutions (national and regional) with traditional influenza surveillance data from the Centers for Disease Control and Prevention (CDC) for accurate, real-time regional tracking of influenza. ARGO2 gives very competitive performance across all US regions compared with available Internet-data-based regional influenza tracking methods, and it has achieved 30% error reduction over the best alternative method that we numerically tested for the period of March 2009 to March 2018. ARGO2 is reliable and robust, with the flexibility to incorporate additional information from other sources and resolutions, making it a powerful tool for regional influenza tracking, and potentially for tracking other social, economic, or public health events at the regional or local level. [ABSTRACT FROM AUTHOR]