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Accelerating performance and braking performance are the core performance of a vehicle, and tire load analysis is a prerequisite for performance studying. A calculation and correction method of dynamic tire loads is proposed in this paper. First, the numerical and experimental models of tire dynamic load identification are established, by measuring the acceleration signals at different positions of the steering knuckle arm, the tire deformation in three directions is inversely calculated. Second, the longitudinal force, lateral force and vertical force of the tire are estimated according to the tire stiffness and deformation. Finally, the tire loads are corrected by data filtering and tire stiffness adjustment. The results show that the average agreement between the calculated load and the test load is more than 90%. The calculation and correction method can provide a theoretical basis and reference for analyzing the dynamic change characteristics of tire load. [ABSTRACT FROM AUTHOR]

In situ87Sr/86Sr microanalysis in bioapatite using laser ablation (LA‐)MC‐ICP‐MS is an essential tool for provenance studies, as enamel tissue build‐up records the regional Sr isotopic composition of ingested food and water sources. Several factors hamper the acquisition of reliable and precise 87Sr/86Sr data: isobaric interferences, elemental and isotopic fractionation of Rb and Sr, and the lack of certified reference materials. Here we thoroughly characterise several teeth from Carcharinus leucas (Bull shark) for the spatial distribution of Sr and Rb mass fraction by LA‐ICP‐Q‐MS, and their 87Sr/86Sr ratio by solution MC‐ICP‐MS, MC‐TIMS and LA‐MC‐ICP‐MS, and which were used subsequently as a reference material during laser ablation measurement of Sr isotope ratios in bioapatite. We establish a protocol to estimate the 85Rb/87Rb mass bias from the analysis of shark teeth that demonstrates that the common assumption of equal Sr and Rb instrument induced fractionation can lead to a systematic bias in 87Sr/86Sr isotope ratios. Using the shark teeth as an "external" reference material to measure βRb yielded 87Sr/86Sr compositions in unknown samples that are within approximately ‐42 ppm to +66 ppm of expected values, instead of approximately ‐50 ppm to +190 ppm if assuming βRb = βSr. Finally, this methodology was tested on fossil gomphotherid (Rhynchotherium sp.) enamel, allowing us to make preliminary inferences about its palaeobiogeography. [ABSTRACT FROM AUTHOR]

Accurate measurement of the pore size distribution (PSD) in coals is crucial for guiding subsequent coalbed methane (CBM) engineering practice. Currently, mercury intrusion porosimetry (MIP) measurement has been widely used as a PSD testing method due to its effectiveness and convenience. Nevertheless, it is worth noting that the elevated pressure during the MIP experiments can lead to matrix compressibility, potentially causing inaccurate estimations of PSD in coals. Therefore, correction methods are used to modify the PSD in the high-pressure segment to improve the accuracy of MIP data. This study proposed a novel method with higher accuracy and convenience for calculating the matrix compressibility coefficient compared to the traditional calculation methods. Firstly, the matrix compressibility coefficients of six coal samples were calculated by using low-temperature nitrogen adsorption (LTNA) data. Subsequently, by utilizing the mathematical correlation between Kc (the compressibility coefficient of the coal matrix) and Ro,max (the maximum vitrinite reflectance) from prior research, a novel statistical method was designed to determine the matrix compressibility coefficient of the samples. Finally, the statistical matrix compressibility coefficient determination method was used to examine the fractal characteristics of the actual PSD. The results indicate that when the pressure exceeds 24 MPa, the volume obtained from mercury intrusion exceeds the pore volume measurement. The Kc calculated using the traditional correction method is in the range of 0.876–1.184 × 10−10 m2/N, while the Kc values of our proposed statistical correction method range from 0.898 × 10−10 to 1.233 × 10−10 m2/N, with a comparison error rate of ~0.11–5.25%. The MIP data greater than 24 MPa were effectively corrected using the statistical correction method, thus reducing the mercury intrusion volume error by 91.75–96.40%. Additionally, the corrected pore fractal dimension (D2) values fall within the range of 2.792 to 2.975, which are closer to the actual values than the pore fractal dimension range of 3.186 to 3.339. [ABSTRACT FROM AUTHOR]

The porous media approach is regarded as an appropriate methodology for hydraulic simulations of complex pebble beds in fusion reactors. In order to determine the parameters (permeability α and inertial loss coefficient C) of the porous media accurately, two methods are proposed: the correction method and the fitting method. In this paper, a single-channel model with sequentially packed pebbles is constructed in order to obtain the pressure drop gradient against superficial velocities. Two methods, the correction method and fitting method, are employed to determine the permeability and inertial loss coefficient, and the results are evaluated with comparisons. Based on the results, both the correction method and fitting method are deemed feasible for the parameter determinations. In consideration of the consumption of resources and time for simulation, the fitting method is recommended during the preliminary design phase to shorten the duration of design, while the correction method is suggested to obtain precise results when the design is accomplished. Both of the methods would be evaluated with the data obtained from experiments in the future. [ABSTRACT FROM AUTHOR]

In the monitoring the discharge of ballast water, the count of living algal cells is of utmost significant. Variable fluorescence, denoted as Fv, stands as an optimal parameter for photosynthetic fluorescence, efficiently charactering the living algal cells count, unaffected by the ballast waters' complex background fluorescence environment. This study deeply investigates the quantitative relationship between Fv and the count of living algal cells. Observations indicate that single cell fluorescence yield (abbreviated as SCF) varies significantly across different algae species, leading to considerable errors in quantifying living algal cell count in ballast water with unknown components using the calibration relationship between Fv and the cell count. Thus, correcting SCF prior to calibration becomes necessary. The paper proposes an innovative SCF correction method based on cell cross-sectional area and an eμ factor (where μ is the expected value of the functional absorption cross-section of PSII) This method mitigates the influence of cell size and species differences on quantifying the living algal cell count. Correction operation trials revealed that dividing the SCF measurement by cell cross-sectional area and multiplying by eμ enhanced the correction effect. Comparative experiments demonstrated marked improvement: Relative errors (REs) for Chlorella pyrenoidosa and Chlorella marine, both belonging to the Chlorophyta group, fell from 92.1% and 90.6% to 37.2% and 9.5% respectively post-correction. Similarly, REs for Thalassiosira weissflogii and Nitzschia closterium minutissima, from the Bacillariophyta group, decreased from 74.7% and 68.1% to 14.3% and 19.1% respectively. The RE of Peridinium from the Pyrrophyta group dropped from 28.4% to 12.1%. The results underscore the effectiveness of cell cross-sectional area and eμ in correcting SCF, thus offering a novel correction method for swift and precise measurement of living algal cell count in ballast water, based on variable fluorescence. [ABSTRACT FROM AUTHOR]

Advances in multi‐collector inductively coupled plasma‐mass spectrometry (MC‐ICP‐MS) have led to the widespread use of iron (Fe) isotopes to elucidate the (bio)geochemical history of a range of environments. To generate Fe isotope ratio measurements, standard‐sample bracketing (SSB) is commonly used to correct for instrumental mass bias inherent to MC‐ICP‐MS. However, SSB is only accurate when sample and isotope standard Fe concentrations match, in addition to the bulk solution matrix. When the Fe concentrations differ, Fe isotope ratio measurement results may be inaccurate, a phenomenon known as the "self‐induced matrix effect." This study systematically characterised the self‐induced matrix effect for dry plasma Fe isotope ratio measurements on three MC‐ICP‐MS instruments and three introduction systems. Our extensive dataset indicates that: (1) the degree of mass bias is consistent regardless of MC‐ICP‐MS front‐end design, (2) the degree of mass bias becomes less reproducible as the concentration difference between the sample and bracketing standard increases, and (3) this applies to both pure Fe solutions and solutions from geological materials. This study reinforces the requirement to match bracketing standard and sample concentrations within 10% and provides a correction method for that fall beyond the recommended concentration range to subsequently allow for proper concentration matching during SSB. [ABSTRACT FROM AUTHOR]

In order to apply the single-constant Kubelka–Munk (KM) model to color prediction of fiber blends, a novel correction method is proposed in the paper. The single-constant KM model is based on the assumption that the ratio of absorption coefficients to scattering coefficients (K/S) of a mixture is linear to mass proportion of its components. However, when it comes to the media of pre-colored fiber blends, the linear assumption always fails, resulting in inaccurate color prediction with large color difference. To solve this problem, a novel correction method was proposed, which improved the linearity of K/S in the way of decreasing the linear deviation. Pre-colored cotton fibers were used to prepare samples to examine the proposed correction method. The average color difference values ΔEcmc (2:1) and ΔE00 of the single-constant KM model with proposed correction method are 1.37 and 1.17 respectively, which are remarkably better than those of the Kubelka–Munk model without correction (~ 8.41 and 6.35) and the Kubelka–Munk model with Saunderson correction (~ 8.63 and 6.55). The results indicate that, for the media of pre-colored fiber blends, the proposed correction method greatly improves the color prediction accuracy. [ABSTRACT FROM AUTHOR]

Diffusion shaped film cooling holes can improve cooling performance on turbine blades of aeroengines. The diffusion structures are difficult to machine due to the complicated shape, especially for the special materials such as single crystal superalloys. In our previous work, a novel process of block divided electrical discharge machining (EDM) based on a slender rod electrode was proposed to efficiently machine the diffuser structure of diffusion shaped film cooling holes. Although the rod electrode wear can be quickly repaired in the block divided EDM process, the shape accuracy of diffuser structures still needs to improvement. In this research, the novel process is firstly analyzed to find that the error of servo feed trajectory in 3D space is a key to the shape accuracy. Furthermore, a correction method of servo-feed tool trajectory is proposed by applying a correction velocity perpendicular to a target trajectory for correcting tool position. The specific implementation algorithm of the correction method is described in detail. The repeated experiments of diffusion structures verify the feasibility of the block divided EDM with trajectory correction method. The experimental results show that the proposed method and algorithm can effectively reduce the trajectory error by ~20 μm and the shape error of diffusion structure by ~10 μm. The typical film cooling holes with diffusion structures were machined successfully on Inconel 718 and nickel-based single crystal superalloys, based on the self-developed experimental setup by integrating the high speed EDM drilling on cylindrical-hole part and the block divided EDM with the trajectory correction method on diffusion-structure part. [ABSTRACT FROM AUTHOR]

As converter stations are increasingly constructed at high altitudes, how to reasonably select the minimum air spacing of converter station substation equipment has become an important issue for DC power transmission at high altitudes. In order to study the influence of air environment on switching impulse discharge characteristics of air gap at high altitudes, this paper conducts switching impulse discharge tests on 1 m rod-plate air gap under different air pressure, temperature, and humidity conditions, investigates switching impulse discharge characteristics of rod-plate air gap at high altitude, and compares and analyses differences in correction results of various discharge voltage correction methods. Studies have shown that air pressure, temperature, and humidity have an effect on air gap discharge voltage. Meanwhile, based on different atmospheric parameters, correction formulas are obtained for 1m rod-plate air gap discharge voltage, and the elevation correction coefficients of 1m rod-plate air gap at each altitude was obtained. The results of the study provide a reference for external insulation of equipment and its insulation fit in converter stations at high altitude.

In order to improve the tooth surface geometric accuracy and transmission quality of the axle bevel gear, a machining errors correction method based on one dimensional probe was proposed, which minimized the geometric deviations of the tooth surface from the point of view of mathematical analysis and engineering reverse. The mathematical relationship among the theoretical design tooth surface, actual machining tooth surface and deviation tooth surface were established. The mapping relationship between the machining parameters of the machine tool and the tooth surface deviations was derived. On this basis, the machining correction model of the machine tool was constructed, and the minimization of tooth surface deviations was realized by adopting the numerical iteration inverse solution method. Through the correction experiment of tooth surface machining errors of an axle bevel pinion, the correctness and practicability of the correction method proposed in this paper were verified. The experimental results show that after correction, the maximum machining errors of the pinion convex and concave surfaces are reduced from 0.134 9 mm to -0.012 7 mm, from 0.241 1 mm to 0.031 6 mm, respectively, and the overall deviation trends of the pinion tooth surface are effectively reduced. [ABSTRACT FROM AUTHOR]

The porous media approach is regarded as an appropriate methodology for hydraulic simulations of complex pebble beds in fusion reactors. In order to determine the parameters (permeability α and inertial loss coefficient C) of the porous media accurately, two methods are proposed: the correction method and the fitting method. In this paper, a single-channel model with sequentially packed pebbles is constructed in order to obtain the pressure drop gradient against superficial velocities. Two methods, the correction method and fitting method, are employed to determine the permeability and inertial loss coefficient, and the results are evaluated with comparisons. Based on the results, both the correction method and fitting method are deemed feasible for the parameter determinations. In consideration of the consumption of resources and time for simulation, the fitting method is recommended during the preliminary design phase to shorten the duration of design, while the correction method is suggested to obtain precise results when the design is accomplished. Both of the methods would be evaluated with the data obtained from experiments in the future.

The hazard coefficient for leakage diffusion of gas transmission pipeline is extremely high, which can easily lead to explosive accidents. The amount of gas leakage is an important factor in the safety assessment of pipeline leakage. Therefore, this paper considers the influence of gas interactions inside and outside the pipeline on pipeline leakage and establishes a three-dimensional leakage diffusion model that is coupled with the pipeline and air domain. Through the use of theoretical, experimental, and numerical simulation methods, this paper investigates the effects of leak hole diameter, leak hole shape, and changes in transport pressure on pipeline leakage. Finally, based on simulated leakage data, we analyze the sources of error and propose a high-precision formula for calculating leakage from small holes in pipelines. The results show that an increase in the diameter of the leak hole leads to a decrease in the central velocity of the leak hole and a sharp increase in leakage volume. The leakage volume of different leak hole shapes is ranked in the following order: rectangle > diamond > circle. When the leak holes are rectangle and diamond, the leakage velocity distribution range of the leak hole is larger and more regular than that of the circular leak hole. Also, the volume of gas leakage increases with the increase in delivery pressure, while the central velocity of the leak hole remains relatively unchanged. Based on the proposed pipeline leakage correction formula, it is calculated that under the same working condition, the relative error range between the numerical simulated leakage rate and the theoretically corrected leakage rate is significantly reduced from −8.40%~18.03% to −1.58%~2.60%, and the calculation accuracy is significantly improved. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department 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.)

The accuracy of the prompt γ-ray analysis is known to degrade for the samples containing neutron-scattering materials, such as hydrogen, depending on its content. Recently, we discovered that the density of the scattering materials also affects the accuracy. In this paper, we developed a correction method for the effect of the sample densities. The developed correction method is straightforward and applicable to samples with unknown densities. The simulation and experiments verified the performance of the correction method. The results confirmed that the correction method could reduce the uncertainty due to sample density from 47% to approximately 1%. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Computational Mechanics / Jisuan Lixue Xuebao is the property of Chinese Journal of Computational Mechanics Editorial Office, Dalian University of Technology 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.)

Hardening is the core factor to determine deformation uniformity in sheet metal forming. Hot deformation of titanium alloy sheets encounters the coupled effects of strain hardening, strain rate hardening and softening, which makes the determination of forming parameters aiming for an enhanced hardening very difficult in practical processes. This paper presents a new model to quantify the hardening of Ti-6Al-4 V titanium alloy sheets under hot forming conditions based on the underlying correlation between uniform strain and hardening. Firstly, to precisely determine hot deformation characteristics of titanium alloy sheets, hot tensile uniaxial tests using Gleeble systems at various strain rates of 0.01–1 s−1 and temperatures of 973–1123 K were performed systematically. A newly developed volume-based correction method for stress–strain curves of Gleeble thermo-mechanical testing was proposed to eliminate the damaging effect of temperature gradients on strain calculations, which enables the strain hardening, strain rate hardening and softening to be determined precisely. Then, a simple unified formula of hardening components (n, m and s) was proposed to predict the achievable uniform strain at certain conditions efficiently. Using which, occupation of each hardening can be quantified and compared to facilitate the determination of process parameters. Finally, a phenomenological model based on the hardening and softening components was developed to predict the hot flow behaviour. The proposed quantitative model can provide an efficient and useful approach for process designers to design process parameters driven by the objective of enhancing hardening to maximize uniform deformation during hot forming of titanium alloy sheets. [ABSTRACT FROM AUTHOR]

Based on the ground incident radiation data of FY-4A and the radiation data of ground weather station， the nowcasting method based on mean generation function is used to obtain the forecast radiation， as well as its rolling correction.Taking Taiyuan station in Shanxi Province as an example， the experiment in 2019 shows that the high spatial-temporal resolution radiation related products provided by the new generation geostationary meteorological satellite FY-4A can provide relatively reliable initial conditions for nowcasting prediction； The nowcasting forecast based on satellite radiation products captures the impact of weather changes， and the revised nowcasting forecast radiation has been effectively improved； In sunny days， the maximum deviation of nowcasting forecast global radiation is improved from about 120 W·m-2 before correction to about 40 W·m-2 after correction.In cloudy days， the average absolute error decreases to 14 W·m-2.In cloudy days， the average absolute error decreases to 56 W·m-2.According to the comprehensive statistical analysis of 16 prediction time steps without considering temporal variation， the corrected nowcasting global radiation and observed global radiation are coincided very well at each prediction time step， the relative error decreased from 44.7%~66.4% to 21.3%~54.3%， and the RMSE decreased from 166.4~198.8 W·m-2 to 132.2~189.9 W·m-2； From the comprehensive statistical analysis of the whole year， the revised correlation coefficient is generally higher than that before the revision， increased from 0.77~0.84 to 0.79~0.88， only slightly decreased at 15 hour， the RMSE decreased from 162.7~197.1 W·m-2 to 129.3~180.9 W·m-2， and the average absolute relative error decreased from 46.0%~76.8% to 24.0%~46.5%.This method can be used for nowcasting prediction of the whole disk at any time.

Globally, a variety of numerical weather prediction (NWP) models are employed by national agencies. However, the derived outputs from these models are generally inadequate for precise cultivation management due to bias error. This study uses observational data acquired over several months to develop an equation for correcting surface air temperature (SAT) error in NWP model outputs. With the proposed method, model outputs are converted into potential temperature to cancel the influence of differences between computational elevation and real elevation. The potential temperature errors in the NWP model outputs are corrected using a linear regression equation in which a radiative cooling scale (RCS) serves as the independent variable. The RCS is computed using air temperature observed at a nearby meteorological observation station, together with upper‐level pressure data from the NWP model. Versions of the correction models are developed for specific situations: day, night, and upper‐level meteorology, classified into six groups. In an application of the proposed method, the root mean square error (RMSE) of the corrected SAT output from a global spectral model operated by the Japan Meteorological Agency (JMA) was 1.2–1.6 K; the RMSE of the corrected SAT output from a nonhydrostatic model operated by the JMA was 1.2–1.5 K. The proposed method corrected the NWP model SAT output errors to a level of accuracy similar to that of data corrected using the Kalman filtering technique without the requirement for constant observation at the target site. [ABSTRACT FROM AUTHOR]

One of the most significant challenges in designing a hyper‐firing‐rate weapon is to balance the interior ballistics behaviors of a multi‐projectile system. This paper proposes a multi‐projectile system with a front nozzle to correct interior ballistic characteristics based on rarefaction wave theory. Firstly, a two‐dimensional two‐phase flow model for the hyper‐firing‐rate weapon is established. Then the application to a standard virtual gun as a benchmark for interior ballistic codes is used to validate the accuracy. In addition, the interior ballistics behaviors of the three‐projectile system without and with the front nozzle are investigated. Finally, the interior ballistics behaviors of the three‐projectile system are corrected by changing the open time of the front nozzle. The results show that the new correction method for the multi‐projectile system reduces the recoil and the pressure while balancing the muzzle velocity. The finding guides future ballistic research on the multi‐projectile system. [ABSTRACT FROM AUTHOR]

Background210Bi is one of the most important interferences in the analysis of 90Sr by extractive chromatography. It is verified by the leaching curve that bismuth and yttrium are completely adsorbed on the chromatographic column in the bis(2-ethylhexyl) phosphate (HDEHP) extraction chromatography, and this two components can not be completely separated, resulting in higher measurement results of 90Sr.PurposeThis study aims to provide a modified method to eliminate 210Bi interference in the analysis of 90Sr by bis(2-ethylhexyl) phosphate (HDEHP) extraction chromatography.MethodsBy collecting the eluent, measuring the content of strontium, yttrium, lead and bismuth in the eluent and drawing the leaching curve, the adsorption and elution behavior of strontium, yttrium, lead and bismuth in the P204 resin were investigated. The residual 210Bi after column separation was experimentally removed by Bi2S3 precipitation or by measuring the sample source repeatedly and correcting the result with formulas.ResultsThe experimental results show that the relative deviation between the modified 90Sr activity and the reference value is within 23% when the activity ratio of 210Bi to 90Sr is not bigger than 5. The results of 90Sr calculated by the modified method for environmental samples are in good agreement with the measured results after bismuth removal by Bi2S3 precipitation.ConclusionsThe interference of 210Bi in the analysis of 90Sr by extractive chromatography can be eliminated by measuring the sample source repeatedly and correcting the result with formulas.

The hazard coefficient for leakage diffusion of gas transmission pipeline is extremely high, which can easily lead to explosive accidents. The amount of gas leakage is an important factor in the safety assessment of pipeline leakage. Therefore, this paper considers the influence of gas interactions inside and outside the pipeline on pipeline leakage and establishes a three-dimensional leakage diffusion model that is coupled with the pipeline and air domain. Through the use of theoretical, experimental, and numerical simulation methods, this paper investigates the effects of leak hole diameter, leak hole shape, and changes in transport pressure on pipeline leakage. Finally, based on simulated leakage data, we analyze the sources of error and propose a high-precision formula for calculating leakage from small holes in pipelines. The results show that an increase in the diameter of the leak hole leads to a decrease in the central velocity of the leak hole and a sharp increase in leakage volume. The leakage volume of different leak hole shapes is ranked in the following order: rectangle > diamond > circle. When the leak holes are rectangle and diamond, the leakage velocity distribution range of the leak hole is larger and more regular than that of the circular leak hole. Also, the volume of gas leakage increases with the increase in delivery pressure, while the central velocity of the leak hole remains relatively unchanged. Based on the proposed pipeline leakage correction formula, it is calculated that under the same working condition, the relative error range between the numerical simulated leakage rate and the theoretically corrected leakage rate is significantly reduced from −8.40%~18.03% to −1.58%~2.60%, and the calculation accuracy is significantly improved.

Abstract Globally, a variety of numerical weather prediction (NWP) models are employed by national agencies. However, the derived outputs from these models are generally inadequate for precise cultivation management due to bias error. This study uses observational data acquired over several months to develop an equation for correcting surface air temperature (SAT) error in NWP model outputs. With the proposed method, model outputs are converted into potential temperature to cancel the influence of differences between computational elevation and real elevation. The potential temperature errors in the NWP model outputs are corrected using a linear regression equation in which a radiative cooling scale (RCS) serves as the independent variable. The RCS is computed using air temperature observed at a nearby meteorological observation station, together with upper‐level pressure data from the NWP model. Versions of the correction models are developed for specific situations: day, night, and upper‐level meteorology, classified into six groups. In an application of the proposed method, the root mean square error (RMSE) of the corrected SAT output from a global spectral model operated by the Japan Meteorological Agency (JMA) was 1.2–1.6 K; the RMSE of the corrected SAT output from a nonhydrostatic model operated by the JMA was 1.2–1.5 K. The proposed method corrected the NWP model SAT output errors to a level of accuracy similar to that of data corrected using the Kalman filtering technique without the requirement for constant observation at the target site.

Reducing carbon emissions is an urgent need in the field of marine power. Gas turbines are of great importance in the marine industry. The use of clean or industrial-associated fuels can increase the fuel adaptability of designed, manufactured, or in-service gas turbines to realize the goal of expanding fuel sources, reducing fuel waste, lowering energy demand, and remitting environmental pressure. By changing from fossil fuel to alternative energy, the change in the physical properties of the combustion products will lead to changes in the working medium of the turbines, which result in a profound effect on the performance. In this study, based on the actual law of working medium property change, the evolution mechanism of turbine characteristics is lucubrated in depth, focusing on the key parameters of the influence of working medium properties on turbine characteristics under alternative fuel conditions, and a correction method is proposed to predict the evolution law of the turbine characteristics as working medium varies.

In seepage analysis, the value of the boundary conditions primarily determines the accuracy of the calculation results. The reservoir impoundment causes a redistribution of the underground seepage field and a change in the groundwater level. At present, the commonly used finite element simulation methods rarely consider the influence of boundary water level changes. To explore the influence mechanism of reservoir impoundment on the boundary water level, based on the Dupuit theory and numerical simulation experiment, the change in groundwater level at the boundary on the mountainsides after impoundment was investigated when the model range was 1400 m, and a correction method for the boundary water level was proposed. The results showed that the distribution of the seepage field before and after the correction was significantly different and cannot be ignored. Subsequently, a large-scale slope model was established. Comparing the numerical solution of the boundary water level with the corrected solution indicated that the maximum relative difference was only 1.4%, proving the reliability of the proposed method. Moreover, the calculation results of the discharge and groundwater levels were underestimated, as the groundwater level rise at the calculation boundary was ignored. The proposed method can correct the water level at the boundary of the model and effectively improve the calculation accuracy of seepage analysis. [ABSTRACT FROM AUTHOR]

The dynamic response of complex equipment under mixed-mode loading is significant for structural design. Bolted joints are the primary connection mode of subsystem assembly, and the degradation of bolted joints may reduce the safety and reliability of the equipment. The Iwan model is widely used to describe the degradation of bolted joints, which has been continuously revised and experimentally verified. The classic Iwan model is a static model that lacks predictive ability. The latest dynamic Iwan model can predict the softening process and reveal the physical mechanism of degradation. However, the function of dynamic pressure distribution needs to be determined for the model solution. We analyzed the contact boundary and pressure distribution under mixed-mode loading with the finite element method (FEM) and proposed the dynamic functions. Secondly, we put forward two correction methods to compensate for the loss of preload caused by simplification and to achieve consistency between the pressure distribution function and the contact boundary function. Finally, the influence of discrete order on the correction of pressure distribution was analyzed. The results show that the constraint method is more suitable for the modification of the pressure distribution. The research results can be applied to the solution of the dynamic Iwan model. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ballistics / Dandao Xuebao is the property of Journal of Ballistics Editorial Department 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.)

Copyright of Plateau Meteorology is the property of Plateau Meteorology Editorial Office 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.)

This study aimed to investigate the fracture and hardening behaviors of transformation induced plasticity (TRIP) steel at different heat-treatments using the uniaxial tensile test and the necking correction method to study the effects of various heat treating procedures and strain rates in the microstructural evaluation, mechanical properties, and fracture behavior of the investigated steel. The uniaxial tensile tests were performed on samples heat-treated through different procedures and strain rates in the range of 0.005–5 s−1. It was observed that the strain rate slightly affects the formability of TRIP steel in different heat-treatment procedures. The obtained results showed that the H3 sample in which the samples austenitized at 900 °C for 22 min then soaked at 400 °C for 1 h and finally quenched in oil at 50 °C and cooling at ambient temperature had the highest strain fracture. The nucleation and growth of voids, as well as the dynamic equilibrium between strain hardening and recovery, were reasons for fracture strain increment from 0.005 to 0.1. However, fracture strain decreased at the strain rate of 0.1–5 s−1 due to the decrease of ductility. Also, TRIP steel characterizations were used for modeling the displacement and stress of the anti-roll bar by ANSYS 19.2 parametric language and Solid-Works. The displacement and stress results of TRIP steel were compared to SAE Class 550 and Class 700 grades of steel. [ABSTRACT FROM AUTHOR]

In this paper, we study a finite element algorithm for the nonstationary incompressible magnetohydrodynamic equations using a correction method. The considered algorithm includes two steps, which involves a post-processing step. In the first step, a fully discrete first-order Euler backward scheme based on the mixed finite element method is applied. Then in the second step, a correction method is used, which does not increase many computational complexity. However, the accuracy of the approximation solution in time can be improved from first to second order after this post-processing step. Further, we prove unconditional stability and estimates for the error of the approximate solution. Finally, the numerical theory and efficiency of the presented algorithm are confirmed by some numerical tests. [ABSTRACT FROM AUTHOR]

Using the daily precipitation data at 81 stations in Anhui province, NCEP 500 hPa height reanalysis data, EC precipitation and 500 hPa height forecast, on the basis of the objective judgment of rainstorm center and weather type, the forecast bias of precipitation center of 23 heavy precipitation events from 2012 to 2018 is classified and counted. The results show that when the EC forecast precipitation center is located in the north of the 584 dagpm line from 115°E to 120°E, the forecast of precipitation center tends to be biased north. According to the latitude difference between the two and the forecast bias of precipitation center, a correction method of main rain belt position based on weather classification is established. meanwhile, according to the daily averaged biases of the precipitation forecast in the maximum precipitation area of 23 heavy precipitation events, a method for correcting the intensity of rainstorm is established. The bias correction method is applied during the plum flood season in Anhui province in 2020, and the results show that the TS score of rainstorm forecast can be significantly improved regardless of the location or intensity correction. After the correction of both location and intensity, the improvement of TS score is more obvious, especially for the two strongest precipitation events in 2020.

Laboratory analysis needs a long time and expensive to determine water quality. A tool that can predict water quality by capturing sound vibrations generated by collisions between water samples and light is LPAS (Laser Photo-Acoustic Spectroscopy). To process the data acquired by LPAS, spectrum correction is needed to eliminate data errors when making acquisitions on water samples. The correction method used in this research is the cutting edge filtering correction method. The regression model that can be used is the PLSR (Partial Least Square Regression) regression model. This research was conducted in the Instrumentation and Energy Laboratory, Agricultural Engineering Study Program, Faculty of Agriculture, Syiah Kuala University. Water sample analysis was carried out at the Laboratory of the Industrial Research and Standardization Center (BARISTAND) Banda Aceh. This study used 4 monitoring wells within the TPA (Final Disposal Site) and 4 samples were taken from community wells outside the scope of TPA Gampong Jawa, Banda Aceh City. The results of this study indicate the parameters (temperature, turbidity, Ph, TSS, DO, BOD and Nitrate) are predicted to be in the frequency range 4000 - 10,000 cm-1. Raw spectrum data for pH and Nitrate (NO3-) parameters produce better data than the spectrum data for cutting edge filtering correction methods while cutting edge filtering spectrum data for temperature, turbidity, TSS, DO and BOD-5 parameters are better than spectrum raw data. This study also shows that the cutting edge filtering correction method is able to cut boundaries and compress the spectrum so that it can provide data limits on the spectrum so that the PLSR method can be applied to predict water quality.

In the present study, the impact of test temperature, specimen geometry, and evaluation methodologies on the fracture toughness of 316L stainless steel was evaluated. Tensile and fracture mechanics tests were conducted utilizing a cryostat across a range of temperatures from ambient conditions to liquid hydrogen environments. The analysis of crack length prediction and resistance curve was performed using two fracture toughness evaluation methods: the unloading compliance method and the normalization method. The difference in fracture toughness by specimen thickness using the normalization method was within acceptable tolerances for all temperatures. However, fracture toughness evaluation using the unloading compliance method showed apparent negative crack growth at all temperatures, causing differences in J-integrals between specimen thicknesses and discrepancies between physical and estimated crack extensions. The application of the offset technique to the unloading compliance method significantly reduced these differences and made the J-integral of the normalization method and the unloading compliance method agree well. The substantial underestimation in the correction of the rotation angle at ambient temperatures was confirmed through real-time imaging of the crack tip with the unloading compliance method, which contributed to the large deviations between estimated and measured crack extensions. [ABSTRACT FROM AUTHOR]

Significant range differences were identified between shallow and deep channels of the Mapper5000 bathymetry light detection and ranging (LiDAR) system with segmented field-of-view (FOV) receivers. Range difference varied with depth and water optical properties. The main feature was the maximum value in range difference curves, which ranged from 0.3 to 0.6 m and usually exceeded the International Hydrographic Organization (IHO) accuracy standards. Sensitivity analyses based on a semianalytical Monte Carlo simulation model revealed that the scattering phase function and laser beam divergence angle played more important roles in causing pulse dispersion and determining the amplitude and position of maximum range difference than absorption and scattering coefficients. A range difference correction method by fitting existing shallow and deep channel data in the overlapping range with a cubic polynomial was proposed to correct the deep channel data in the entire depth range that LiDAR can detect. Depth discontinuity at the junction of the shallow channel and deep channel measurements was successfully removed, and the mean and standard deviation of corrected range differences were within 0.01 and 0.1 m, respectively. A combination of range difference correction and mean bias corrector can be an alternative method for depth bias correction of segmented-FOV LiDAR when referenced sonar data is not available. [ABSTRACT FROM AUTHOR]

Programmed mini-pumps play a significant role in various fields, such as chemistry, biology, and medicine, to transport a measured volume of liquid, especially in the current detection of COVID-19 with PCR. In view of the cost of the current automatic pipetting pump being higher, which is difficult to use in a regular lab, this paper designed and assembled a three-dimensional programmed mini-pump with the common parts and components, such as PLC controller, motor, microinjector, etc. With the weighting calibration before and after pipetting operation, the error of the pipette in 10 μ L (0.2%), 2 μ L (1.8%), and 1 μ L (5.6%) can be obtained. Besides, the contrast test between three-dimensional programmed mini-pump and manual pipette was conducted with the ORF1ab and pGEM-3Zf (+) genes in qPCR. The results proved that the custom-made three-dimensional programmed mini-pump has a stronger reproducibility compared with manual pipette (ORF1ab: 24.06 ± 0.33 vs. 23.50 ± 0.58, p = 0.1014; pGEM-3Zf (+): 11.83.06 ± 0.24 vs. 11.50 ± 0.34, p = 0.8779). These results can lay the foundation for the functional, fast, and low-cost programmed mini-pump in PCR or other applications for trace measurements. [ABSTRACT FROM AUTHOR]

Diagnostic tests play a crucial role in medical care. Thus any new diagnostic tests must undergo a thorough evaluation. New diagnostic tests are evaluated in comparison with the respective gold standard tests. The performance of binary diagnostic tests is quantified by accuracy measures, with sensitivity and specificity being the most important measures. In any diagnostic accuracy study, the estimates of these measures are often biased owing to selective verification of the patients, which is referred to as partial verification bias. Several methods for correcting partial verification bias are available depending on the scale of the index test, target outcome, and missing data mechanism. However, these are not easily accessible to the researchers due to the complexity of the methods. This article aims to provide a brief overview of the methods available to correct for partial verification bias involving a binary diagnostic test and provide a practical tutorial on how to implement the methods using the statistical programming language R. [ABSTRACT FROM AUTHOR]

Multiple factors including rainfall and underlying surface conditions make river basin real-time flood forecasting very challenging. It is often necessary to use real-time correction techniques to modify the forecasting results so that they reach satisfactory accuracy. There are many such techniques in use today; however, they tend to have weak physical conceptual basis, relatively short forecast periods, unsatisfactory correction effects, and other problems. The mechanism that affects real-time flood forecasting error is very complicated. The strongest influencing factors corresponding to this mechanism affect the runoff yield of the forecast model. This paper proposes a feedback correction algorithm that traces back to the source of information, namely, modifies the watershed runoff. The runoff yield error is investigated using the principle of least squares estimation. A unit hydrograph is introduced into the real-time flood forecast correction; a feedback correction model that traces back to the source of information. The model is established and verified by comparison with an ideal model. The correction effects of the runoff yield errors are also compared in different ranges. The proposed method shows stronger correction effect and enhanced prediction accuracy than the traditional method. It is also simple in structure and has a clear physical concept without requiring added parameters or forecast period truncation. It is readily applicable in actual river basin flood forecasting scenarios. HIGHLIGHTS From the perspective of system theory, an RSCR method to modify production flow is proposed.; This method uses the system response curve feedback of the production flow in each period to correct the production flow in each period.; The validity and practicability of the method are proved by numerical simulation experiments with different random distribution errors.;

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office 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.)

A new correction method for laser Doppler velocimetry (LDV) measurement volume effects on the time-averaged velocity statistics is proposed by considering the probability density function of streamwise fluctuating velocity and the streamwise cross-sectional area of the measurement volume. The proposed correction method is fundamentally different from previous correction methods using a laser intensity profile of LDV. We propose a simple equation to correct the measurement volume effects. By using the equation and calculating both measurement locations and volumes precisely, the correction for the measurement volume effects on time-averaged velocity statistics can be performed on the basis of LDV measurement data. By comparing with the correction method proposed by Durst et al. (1995), the two correction methods provide almost the same results. In addition, the validity and applicability to high Reynolds numbers or low spatial resolution conditions of the two correction methods are confirmed. [ABSTRACT FROM AUTHOR]

Novel sensors for ultrashort-distance measurements, with choke flanges applied at the open ends of both a WR10 waveguide and a circular waveguide, featuring a radius of 1.42 mm, are proposed. Field distributions between the sensors and a target are analyzed and explained on the basis of higher order modes of a radial line formed by the sensors and a planar reflective target. A robust equivalent circuit using a cascade of lossy waveguides is proposed and a new calibration/correction method is derived. Properties of both sensors are verified experimentally for target distances of 0–6 mm (more than one and half of wavelength). The new circular waveguide sensor operates in a frequency band of 75-76 GHz with a maximum error of measured distance $19~\mu \text{m}$. The new rectangular waveguide sensor enables to use an outstanding applicable frequency bandwidth from 76 up to 86 GHz, with best properties around 80 GHz, where the maximum error of the measured distance is 12 $\mu \text{m}$. The new sensors make possible to achieve about ten times smaller distance measurement errors in comparison with the state-of-the-art sensors. [ABSTRACT FROM AUTHOR]

Real-time simulation of power electronics has been recognized by the industry as an effective tool for developing power electronic devices and systems. Since there is no energy transfer during the course of the usage, real-time simulation has a lot of advantages in the process of development and experimentation. From the perspective of real-time simulation, this paper focuses on the main problems in modeling accuracy, system bandwidth and stability, limitations on communication interface and energy interface, and the cost of platform construction. Finally, we provide further research directions.

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology 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.)

In medical care, it is important to evaluate any new diagnostic test in the form of diagnostic accuracy studies. These new tests are compared to gold standard tests, where the performance of binary diagnostic tests is usually measured by sensitivity (Sn) and specificity (Sp). However, these accuracy measures are often biased owing to selective verification of the patients, known as partial verification bias (PVB). Inverse probability bootstrap (IPB) sampling is a general method to correct sampling bias in model-based analysis and produces debiased data for analysis. However, its utility in PVB correction has not been investigated before. The objective of this study was to investigate IPB in the context of PVB correction under the missing-at-random assumption for binary diagnostic tests. IPB was adapted for PVB correction, and tested and compared with existing methods using simulated and clinical data sets. The results indicated that IPB is accurate for Sn and Sp estimation as it showed low bias. However, IPB was less precise than existing methods as indicated by the higher standard error (SE). Despite this issue, it is recommended to use IPB when subsequent analysis with full data analytic methods is expected. Further studies must be conducted to reduce the SE.

Background: Walking speed is a confounding factor in biomechanical analyses of gait, but still many studies compare gait biomechanics at comfortable walking speed (CWS) that is likely to differ between groups or conditions. To identify gait deviation unrelated to walking speed, methods are needed to correct biomechanical data over the gait cycle for walking speed.Research Question: How to compare knee kinetics over the gait cycle at different walking speeds?Methods: 22 asymptomatic subjects walked on a dual-belt treadmill at CWS and 4 fixed speeds. Knee moments in sagittal (KFM) and frontal plane (KAM) were calculated via inverse dynamics. The net moment differences between CWS and fixed speed were expressed as a root-mean-square error (RMSE) normalized to the range of the variable. Two methods to correct for walking speed were compared. In method 1, KFM and KAM values were estimated based on interpolation between speeds at each percentage of the gait cycle. In method 2, principal component analysis was used to extract speed related features to reconstruct KFM and KAM at the speed of interest. The accuracy of both methods was tested using a leave-one-out cross validation.Results: Walking speed influenced the magnitude and shape of KFM and KAM. To account for these speed influences using both methods, leave-one-out cross validation showed low normalized RMSE (< 5 %), with little difference between the two methods. RMSE for both reconstruction methods were up to 60 % lower than the RMSE between CWS and fixed speed.Significance: Both methods could accurately correct knee kinetics over the gait cycle for the effects of walking speed. Walking speed dependency should be incorporated in each gait laboratory's reference dataset to be able to identify gait deviations unrelated to gait speed. [ABSTRACT FROM AUTHOR]