Calculation Method Research Articles

Analysis of the Spatial Constraints of Urban Underpass Channels Based on BIM

The construction of urban underpasses faces various spatial constraints, which will lead to deformation or failure of the structures if not satisfied. The introduction of BIM (Building Information Modeling) and other modern information technology to achieve rapid and accurate spatial constraint analysis of the design scheme is of great significance to ensure the quality and safety of the underpass and adjacent structures. Firstly, through extensive literature collection and survey, the key spatial constraint indicators of underpasses in dense urban spaces and the evaluation rules of each indicator are determined. Then, an SQL (Structured Query Language)-based database of spatial constraint rules for underpasses in dense urban space areas is constructed, and the spatial constraint analysis process for underpasses in dense urban space areas is proposed. Finally, based on Building Information Modeling, programming support, and a development environment provided by C# and Visual Studio, a spatial constraint analysis system for underpasses in dense urban space areas is developed to realize complex spatial constraint analysis functions. The application practice of the system is carried out by taking a city underpass project as an example. The results show that in the design of urban underpass engineering, the spatial constraint analysis system designed in this paper and the calculation method adopted can simplify the model transmission process, save on labor costs, and reduce the error of the calculation results.

A Review on Mechanism and Influencing Factors of Shear Performance of UHPC Beams

Ultra-High-Performance Concrete (UHPC) is increasingly used in various engineering projects due to its exceptional mechanical properties. This work conducts a literature review of research on the shear performance of UHPC beams in recent decades, with a focus on summarizing the formulas for calculating shear capacity and the main factors influencing shear performance. Firstly, this work reviews the calculation methods for the shear capacity of UHPC beams in different countries, along with their respective advantages and limitations. Subsequently, it provides a detailed analysis of various factors influencing the shear performance of UHPC beams, including longitudinal and stirrup reinforcement, steel fiber content, aggregates, admixtures, the shear-span ratio, shear keys, bolts, shear-reinforcement techniques, and environmental impacts. Through horizontal comparisons, the performance of UHPC beams and ordinary concrete beams under similar experimental conditions is examined to reveal the optimal shear working conditions for UHPC beams. Additionally, it is found that UHPC performs exceptionally well in composite beams, being compatible with numerous materials and significantly enhancing the shear strength of these beams. Lastly, the paper proposes suggestions for maximizing the shear performance of UHPC beams within a safe and reliable operating range and outlines future research directions.

Simulation of Total Harmonic Distortion of Solid Oxide Fuel Cells for Carbon Deposition Detection

Abstract Identifying the degradation mechanisms at the early stage of operation is important for the long-term operation of solid oxide fuel cells (SOFCs). Compared to conventional methods, total harmonic distortion analysis (THDA) can significantly reduce the test time for identifying performance degradation during SOFC operation. In this study, a one-dimensional transient elementary reaction kinetic model of an SOFC fueled with syngas is developed. The model incorporates the coupling effect of elementary chemical and electrochemical reactions, the electrode microstructure, the charge and mass transport processes, and the detailed evolution reaction of surface adsorbed carbon. A THDA simulation calculation method was developed and applied to determine the failure mode of anode carbon deposition. The amplitude, duration, and harmonic number of the perturbation signal are determined to improve fault detection for THDs. The results show that the use of THD can not only detect carbon accumulation behavior at the early stage of SOFC operation but also distinguish the specific degradation mechanism caused by carbon deposition: the hindered SOFC charge transfer reaction can be detected in the frequency range of 100-4000 Hz, and the hindered gas diffusion process inside the anode can be detected in the frequency range of 0.01-10 Hz.

Elucidating proper framework for determination of threading dislocation densities in semiconductor films: a comprehensive study based on Ge/Si(001)

Abstract Method of deducing threading dislocation densities (TDDs) from X-ray diffraction (XRD) peak widths has been reevaluated based on crystallography theories, and Ge/Si heteroepitaxial structures were taken as model materials for investigation. The procedure was tailored in accordance with the specific designs of modern XRD systems to minimize instrumental interference, while practical characteristics of heteroepitaxial films was also considered to avoid intrinsic errors. TDDs of samples grown with different epitaxy methods were investigated by using the newly implemented XRD method as well as etch pit density (EPD) method, and satisfactory agreement has been achieved among 3 independently calculated sets of TDD results: two from XRD and one from EPD. Those values were further corroborated by cross-sectional TEM analysis. Key considerations that are of scientific and technical importance in TDD studies were also discussed in detail. The current work has provided not only the most up-to-date elucidation on obtaining TDD values in semiconductor epitaxial films, but also insight into the long-existing ambiguity in TDD calculation methods, which will be helpful for future studies of defect density characterizations on various material systems.

Development of calculation methods for the uncertainty of special mechanical characteristics of structural steel

Understanding of an accuracy related to the evaluation of special mechanical performances of materials is an essential part of the quality control system providing for safe operation of modern structures in severe climatic conditions in far locations where any emergency and repair activities are hindered. In absence of a priori known values of such performances the methodic basis of uncertainty calculation procedures should be developed. Relevance of the problem is supported by the requirement of Russian Accreditation Agency regarding the availability and due application of the corresponding methods in test laboratories as for directly measured parameters as for ones calculated from the test results. Uncertainty calculation procedures are suggested as a background for the developed specialized software.

Computer simulation of x-ray section topography of gas pores in a silicon carbide crystal

The results of computer simulation of images of gas pores in a silicon carbide crystal in sectional topograms, that is, during diffraction of a narrow beam of X-rays in the crystal, are presented for the first time. For this purpose, a special module of the universal computer program XRWP was used. This program is developing by the author to calculate the effects of coherent X-ray optics. The calculation method combines two methods, previously known, namely, Fourier transform methods (Kato method), and the method of solving the Takagi-Taupin equations. It is shown that gas pores can produce a wide variety of images, depending on the experimental conditions and the position of the gas pore inside the crystal.

Probability‐Based Finite‐Time Security Control for Switched Stochastic Systems via a Novel Event‐Triggered Mechanism and Its Application

ABSTRACTThis article discusses the finite‐time boundedness (FTB) issue and ‐gain analysis for switched stochastic systems, particularly under the dual influence of DoS attacks and false data injection attacks, by employing a novel event‐triggered mechanism. Different from the moment calculation method, a probability‐based FTB is studied which offers more pertinence. To obtain a less conservative condition of FTB, a switched Lyapunov function is constructed. Additionally, a memory‐based dynamic event‐triggered mechanism is designed to reduce the amounts of triggering and mitigate the state response fluctuations. Based on the incomplete information above, state feedback controllers are devised to satisfy stochastic FTB, ensuring the successful attainment of finite‐time ‐gain. Sufficient conditions are cast into a convex optimization problem by LMIs which can be solved easily. Finally, a compared numerical example and an RLC series circuit are adopted to demonstrate the availability of the theoretical results.

The Use of Laser Sensing for Solving Meteorological Problems Related to Researching and Ensuring the Safety of Space Flights

This paper is devoted to the issue of using laser (lidar) sensing to determine wind speed and direction when solving practical problems during the analysis of meteorological conditions in the area around spaceports. This issue is relevant both for making decisions on the possibility of a safe launch of a launch vehicle and for conducting search and rescue operations using groups of manned and unmanned aerial vehicles. Based on numerical and experimental modeling, it is shown that lidars provide highly accurate measurements of wind speed profiles and allow for the determination of weak wind shear in vertical and horizontal directions. This paper proposes a method for determining the main parameters of lidar sensing (range, resolution, detectability, etc.), which allows for the capabilities of this technology in solving the practical problems of meteorological monitoring to be predicted. Of particular interest in this article are experimental modeling data verifying the proposed calculation methods and the experimental determination of the capabilities of lidar diagnostics. This paper summarizes the data from multi-month experiments measuring wind speed in clear weather conditions when other means of remote diagnostics are ineffective. As a result of the experiments, a statistical distribution of the maximum range of wind speed measurement in normal weather conditions with natural variation in the concentration of scattering particles in the atmosphere was obtained. This article also discusses the possibility of combining lidars and meteorological radars for the meteorological support of flights.

A Study on the Influence of Hydraulic Compactor Reinforcement on the Force Law of an Independent Foundation Under a Column and Its Safety Standard

Due to the complexity of the actual geotechnical environment, the backfill compaction design theory and calculation method are not reflected in the current specification. Therefore, in order to investigate the effect of the hydraulic compactor on the foundation structure during the treatment of the backfill of an independent foundation under a column, the Menard formula was modified. At the same time, relying on an independent foundation project under a column in Jinan, the dynamic model of compactor tamping backfilling soil was established. The applicability of the calculation formula is verified by simulating the single-point multiple tamping on the backfill directly above the foundation tie beam, and the influence law of two factors, the thickness of the backfill and the tamping energy, on the force of the foundation tie beam is elucidated. The results show that after reaching the optimum number of tamping, the cumulative soil settlement and the effective reinforcement depth of tamping show a stable trend, and their simulation results are in good agreement with the analytical solution, which provides a supplement to the relevant safety standards. At this critical point, the force on the tie beams peaked and showed up and down fluctuations under the subsequent ramming action. The tamping action of the compactor has a significant effect on the structural forces within the effective reinforcement range, and there is a negative correlation between the magnitude of the structural forces and the thickness of the backfill. According to the numerical calculation results to choose the best construction programme, the on-site monitoring shows that under 42 KJ tamping energy and 1.5 m single backfilling thickness, the tie beam reinforcement stress reaches 18.5~55.5% of the specification warning value, which meets the safety standard. The research results of this paper can provide important guidance for the hydraulic tamping treatment of an independent foundation backfill project.

The effects of screen-based simulation on nursing students’ acquisition of medication administration and dosage calculation skills: a randomized controlled trial

BackgroundScreen-based simulation is a cost-effective educational modality that allows nursing students to comfortably acquire new skills as they become accustomed to digital environments. The aim of this study is to evaluate the effectiveness of a screen-based simulation tool in enhancing knowledge and skills related to medication administration and dosage calculation in nursing students.MethodsThis multicenter, single-blind, stratified, randomized controlled trial initially enrolled 480 nursing students. The 351 students eligibles were randomly allocated to two groups. Using a screen-based simulation tool (SIMDOSE®), the intervention group was trained in drug administration and dosage calculation through four perfusion clinical cases. The control group underwent the same training content using the paper-and-pencil method. knowledge and skills acquisition, Students’ satisfaction, self-confidence and anxiety were analyzed using Jamovi software (version 2.3.18).Results4 out of 5 main variables examined were significantly different, specifically in dosage calculation, where the simulation group excelled both in the knowledge post-test (post – pre = 1.00 (20%); p = 0.004) and in the objective structured clinical examination (p = 0.013). The intervention group reported higher levels of satisfaction and self-confidence than the control group (p < 0.001). Their moderate anxiety levels didn’t differ significantly (0.161).ConclusionThe SIMDOSE® platform can be used as a supplementary teaching method of dosage calculation for nursing students. Screen-based simulation has benefits that nurse educators should be aware of, such as being a key to more satisfied and confident students.Trial registrationThis Moroccan clinical trial was prospectively registered (16/05/2023) in the Pan African Clinical Trial Registry (pactr.samrc.ac.za) with trial registration number PACTR202305505743210.

Monte Carlo dose calculation for photon and electron radiotherapy on dynamically deforming anatomy.

Dose calculation in radiotherapy aims to accurately estimate and assess the dose distribution of a treatment plan. Monte Carlo (MC) dose calculation is considered the gold standard owing to its ability to accurately simulate particle transport in inhomogeneous media. However, uncertainties such as the patient's dynamically deforming anatomy can still lead to differences between the delivered and planned dose distribution. Development and validation of a deformable voxel geometry for MC dose calculations (DefVoxMC) to account for dynamic deformation in the dose calculation process of photon- and electron-based radiotherapy treatment plans for clinically motivated cases. DefVoxMC relies on the subdivision of a regular voxel geometry into dodecahedrons. It allows shifting the dodecahedrons' corner points according to the deformation in the patient's anatomy using deformation vector fields (DVF). DefVoxMC is integrated into the Swiss Monte Carlo Plan (SMCP) to allow the MC dose calculation of photon- and electron-based treatment plans on the deformable voxel geometry. DefVoxMC is validated in two steps. A compression test and a Fano test are performed in silico. Delta4 (for photon beams) and EBT4 film measurements in a cubic PMMA phantom (for electron beams) are performed on a TrueBeam in Developer Mode for clinically motivated treatment plans. During these measurements, table motion is used to mimic rigid dynamic patient motion. The measured and calculated dose distributions are compared using gamma passing rate (GPR) (3% / 2mm (global), 10% threshold). DefVoxMC is used to study the impact of patient-recorded breathing motion on the dose distribution for clinically motivated lung and breast cases, each prescribed 50Gy to 50% of the target volume. A volumetric modulated arc therapy (VMAT) and an arc mixed-beam radiotherapy (Arc-MBRT) plan are created for the lung and breast case, respectively. For the dose calculation, the dynamic deformation of the patient's anatomy is described by DVFs obtained from deformable image registration of the different phases of 4DCTs. The resulting dose distributions are compared to the ones of the static situation using dose-volume histograms and dose differences. DefVoxMC is successfully integrated into the SMCP to enable the MC dose calculation of photon- and electron-based treatments on a dynamically deforming patient anatomy. The compression and the Fano test agree within 1.0% and 0.1% with the expected result, respectively. Delta4 and EBT4 film measurements agree with the calculated dose by a GPR>95%. For the clinically motivated cases, breathing motion resulted in areas with a dose increase of up to 26.9Gy (lung) and up to 7.6Gy (breast) compared to the static situation. The largest dose differences are observed in high-dose-gradient regions perpendicular to the beam plane, consequently decreasing the planning target volume coverage (V95%) by 4.2% for the lung case and 2.0% for the breast case. A novel method for MC dose calculation for photon- and electron-based treatments on dynamically deforming anatomy is successfully developed and validated. Applying DefVoxMC to clinically motivated cases, we found that breathing motion has non-negligible impact on the dosimetric plan quality.

Green extraction and partial purification of roselle (Hibiscus sabdariffa L.) extracts with high amounts of phytochemicals and in vitro antioxidant and antibacterial effects.

The aim of this study is to develop roselle (Hibiscus sabdariffa L.) extracts with high amounts of phytochemicals and in vitro antioxidant and antibacterial effects using green extraction technique. Roselle extract prepared by ultrasonic extraction with 80% ethanol and 1% hydrochloric acid (RSUEH) promoted the highest yield and high total phenolic (5.21±0.05g% gallic acid equivalent of dried extract), total flavonoid (1.29±0.06g% quercetin equivalent of dried extract), and total anthocyanin contents (0.21±0.00 and 0.44±0.00g% cyanidin 3-glucoside equivalent of dried extract determined by pH-differential method with standard calculation and pH-differential method with standard curve of cyanidin 3-glucoside, respectively). From the validated high-performance liquid chromatography analysis, delphinidin-3-sambubioside, delphinidin-3-glucoside, and cyanidin-3-glucoside were found to be the major anthocyanins in roselle extract. This extract exhibited moderate 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging effect (EC50 289.61±0.16µg/mL) and strong inhibitory effects against Escherichia coli, Staphylococcus aureus, Staphylococcus intermedius, Proteus mirabilis, and Pseudomonas aeruginosa with the inhibitory concentration (IC50) values in the range of 0.15±0.05 to 4.64±0.07mg/mL and the minimum inhibitory concentration (MIC) values ranged from 1.66±0.06 to 7.11±1.05mg/mL. From partial purification, fraction 28 (F28) contained higher amounts of all analyzed phytochemicals than roselle extracts and promoted stronger DPPH scavenging effects (EC50 54.88±2.23µg/mL). F28 showed antibacterial activity with IC50 values against all tested bacteria in the range of 0.19±0.07 to 4.69±0.09mg/mL, and the MIC values ranged from 2.46±0.08 to 6.24±0.09mg/mL.

Quantifying particulate matter emission rates from naturally ventilated dairy buildings by considering roof opening contributions

Roof openings are typically fitted to naturally ventilated dairy building (NVDB) for better ventilation but their impact on air pollutant emission calculations has not been fully considered. Particulate matter (PM) emission rate (ER) for NVDB rely on the total ventilation rate (VR), outdoor PM concentration and average indoor PM concentration sampled either under the roof (Roof Sampling) or in the cubicle area (Cubicle Sampling), which may show large deviations due to its spatiotemporal variation of PM concentrations and complex airflow patterns. This study utilised a novel ER calculation method (Joint Sampling) that computes the respective emission from the roof and sidewall openings by matching each outlet's VR and PM concentration. By year-round field measurements of PM2.5 and the total suspended particulates (TSP), results showed that annual average ERs of PM2.5 and TSP were 10.8 mg h−1 cow−1 and 45.7 mg h−1 cow−1 for Roof Sampling, 12.7 mg h−1 cow−1 and 40.7 mg h−1 cow−1 for Cubicle Sampling, and 11.7 mg h−1 cow−1 and 45.9 mg h−1 cow−1 for Joint Sampling. Considering the Joint Sampling results were relatively true, Roof Sampling exhibited a maximum underestimate of PM2.5 emissions of 20.8% when sidewall curtains were fully opened, whilst Cubicle Sampling demonstrated a maximum overestimate of TSP of 10.2% when the aperture was closed. Using Joint Sampling, the roof opening contributed 39.3% and 24.4% of the annual PM2.5 and TSP emissions. When sidewall openings are partially or fully closed, the Joint Sampling calculation is preferable to estimate the ER of PM.

High-Precision Disparity Estimation for Lunar Scene Using Optimized Census Transform and Superpixel Refinement

High-precision lunar scene 3D data are essential for lunar exploration and the construction of scientific research stations. Currently, most existing data from orbital imagery offers resolutions up to 0.5–2 m, which is inadequate for tasks requiring centimeter-level precision. To overcome this, our research focuses on using in situ stereo vision systems for finer 3D reconstructions directly from the lunar surface. However, the scarcity and homogeneity of available lunar surface stereo datasets, combined with the Moon’s unique conditions—such as variable lighting from low albedo, sparse surface textures, and extensive shadow occlusions—pose significant challenges to the effectiveness of traditional stereo matching techniques. To address the dataset gap, we propose a method using Unreal Engine 4 (UE4) for high-fidelity physical simulation of lunar surface scenes, generating high-resolution images under realistic and challenging conditions. Additionally, we propose an optimized cost calculation method based on Census transform and color intensity fusion, along with a multi-level super-pixel disparity optimization, to improve matching accuracy under harsh lunar conditions. Experimental results demonstrate that the proposed method exhibits exceptional robustness and accuracy in our soon-to-be-released multi-scene lunar dataset, effectively addressing issues related to special lighting conditions, weak textures, and shadow occlusion, ultimately enhancing disparity estimation accuracy.

Comparison of Vancomycin AUC24 Calculation Methods for Neonates and Infants.

For neonates and infants receiving intermittent vancomycin infusions, the area under the concentration-timecurve during 24 h (AUC24) is often estimated with Bayesian forecasting using one or more measured vancomycin concentrations. When practical peak and trough concentrations are measured at steady state, AUC24 can also be calculated with first-order steady-state equations for a one-compartment model (Sawchuk-Zaske method), but previously this method has been applied only for adults. The objective of this studywas to compare AUC24 values obtained with the Sawchuk-Zaske method and two Bayesian models. AUC24 values were estimated retrospectively for 18 neonates and infants with steady-state peak and trough concentrations using traditional compartmental analysis with a one-compartment model (reference method), the Sawchuk-Zaske method, and Bayesian forecasting with two previously published models. In Bayesian forecasting, both original and modified residual error models were used. In the modified models, the residual error was reduced by setting the additive residual error to zero and the proportional error to 15%. AUC24 estimates obtained with the Sawchuk-Zaske method differed -2.7 to 0.9% from the reference method. When both peak and trough concentrations were used in Bayesian forecasting, 61% and 33% of AUC24 estimates obtained with two original models differed less than 15% from the reference method, and these fractions increased to 83% and 72% with the modified models, respectively. When practical peak and trough concentrations are measured at steady state, the simple Sawchuk-Zaske method is very useful for AUC24 estimation in neonates and infants. In Bayesian forecasting, the reduced residual error model can be used to improve the model fit.

Calculation acceleration for fuel cycle simulation of molten salt reactor based on multi-group cross section method

The time-consuming issue of transport calculations is prominent in the burnup calculation of nuclear reactor. Multi-Group Cross Section (MGXS) method is an acceleration technique developed based on the characteristics of Monte Carlo simulation, which can significantly reduce the computation time required to solve a single group cross section in transportation calculations. The effectiveness of the method has been verified in the test calculations of water reactor pins. However, liquid molten salt reactors (MSRs) exhibit significant differences from conventional water reactors in terms of neutron energy spectra and fuel cycle mode. The effectiveness of the MGXS method in MSR burnup simulations remains to be validated, and targeted adjustments are required during its application. In this study, OpenMC and ORIGEN2 are coupled to develop an accelerated calculation method for MSR burnup simulations based on the MGXS approach. The reasonable grouping structure of the MGXS method is explored, and the performance of different grouping structures is tested. Results show that the transport calculation can be accelerated by an average factor of 2.4 for a single burnup zone by using MGXS method and the acceleration effect is generally independent of the grouping structure adopted. The nuclide mass bias compared to the traditional direct solution can be reduced to approximately 1% when the fuel burnup is 250MWd/kg for the LEU loading scheme with the 10000 groups structure. For the TRU loading scheme, the mass bias compared to the traditional direct solution of important nuclides (such as U-233, U-235, Pu-239 and so on) can be controlled below 0.5% at a burnup of 230 MW d/kg. The results indicate that the grouping strategy proposed in this study can achieve the adaptation of MGXS to MSRs, and the 10000 groups structure adopted in the study exhibits good accuracy.

Tension performance of joint made in cold-formed square tube with self-tapping screw connections

The tension behavior of cold-formed square tube (CFST) screw connections was investigated experimentally and numerically. Ten test specimens were fabricated from the square tubes connected by external steel plates and internal tube applying self-tapping screws such that the number of screws was varied. In addition, the mechanical properties of the single-screw connections were obtained through single shear tests. Experimental results revealed that an increase in the number of screws led to higher bearing capacity and stiffness in the specimens. Shear failure of the screws was observed as the primary failure mode. When the number of the screws was equal in both types of the specimens, those with the internal tube exhibited superior tensile behavior than the ones with external steel plates. Subsequently, finite element (FE) models of the test specimens were developed. Upon validation of the test results, an extensive parametric study was conducted to further examine the influence of the design parameters on the tensile behavior of the CFST screw connections. Variation of the arrangement of screws, wall thickness of steel plates and their strength had only a minor influence on the tension behavior, and steel strength had little influence on the tension behavior and the number, spacing, and diameter of the screws were the key parameters affecting the tension behavior of the CFST screw connections. Based on the test results and FE analyses, the existing calculation method was modified, and a formula for calculating the tensile bearing capacity of the CFST screw connections was obtained. Comparison with the results indicate that the formula was conservative and reliable for determining the tensile capacity of CFST screw connections.

Axial compressive properties of round bamboo-fiber reinforced phosphogypsum composite short columns

Bamboo is an ideal green building material with excellent mechanical properties. Phosphogypsum (PG) is a kind of solid waste residue which is in urgent need of resource utilization and has been used as construction material. In this paper, a kind of round bamboo-fiber reinforced phosphogypsum composite short column was proposed. Axial compression tests of pure bamboo columns, bamboo columns filled with phosphogypsum inside, bamboo columns with phosphogypsum outside and bamboo columns with phosphogypsum inside and outside were carried out to explore the failure mode and mechanical properties of the short columns. The effects of the parameters include bamboo node, hose hoops, size of the bamboo tube and the strength of phosphogypsum on the mechanical properties of the short columns were analyzed, and the theoretical calculation method of the bearing capacity of the short columns was put forward. The results show that the bamboo nodes and hose hoops can improve the bearing capacity, initial stiffness and ductility of the column. The larger the size of the bamboo tube, the better the mechanical properties of the short column. The bearing capacity of round bamboo—phosphogypsum composite short column is higher than that of pure bamboo column. The ductility of bamboo columns with phosphogypsum outside is obviously higher than that of pure bamboo columns. The finite element analysis results are in good agreement with the test results. The theoretical calculation method of the bearing capacity of columns considering the strength reduction coefficient, the bamboo node effect coefficient and the constraint effect in this paper has high accuracy.

Diagnostic Value of the Voltage-to-Mass Ratio in Biopsy-Proven Cardiac Amyloidosis.

The calculation of left ventricular mass varies in different studies, and reference values of the voltage-to-mass ratio for diagnosing cardiac amyloidosis (CA) are lacking. This study aimed to determine the value of the voltage-to-mass ratio in diagnosing CA and provide an optimal cut-off value for different calculation methods. We reviewed the electrocardiograms and echocardiograms of 213 consecutive biopsy-proven CA patients, 236 hypertrophic cardiomyopathy (HCM) patients, 100 hypertensive heart disease patients, and 181 healthy controls. Left ventricular mass was calculated using linear and cross-sectional area (CSA) methods. The voltage-to-mass ratios were compared between the CA group and other groups. The voltage-to-mass ratio obtained was used to build multivariate logistic regression models that predicted the log odds of developing CA. The CA group had a significantly lower voltage-to-mass ratio than the HCM, hypertensive heart disease, and healthy control groups. The voltage-to-mass ratio was an independent factor significantly associated with the CA diagnosis after adjusting for baseline characteristics. Linear and CSA methods yielded areas under the ROC curve of 0.86 and 0.90, respectively. Using the CSA method, the optimal cut-off was 16.42 mV/mm2/m2, with 89.0% sensitivity and 80.8% specificity. The voltage-to-mass ratio could differentiate patients with CA, HCM, and hypertensive heart disease from healthy controls, potentially providing an accurate and non-invasive alternative to current expensive and invasive diagnostic techniques.

Modified Easley formula for elastic critical global shear buckling stress of corrugated steel webs considering real boundary conditions

The real juncture between corrugated steel webs (CSWs) and flanges follows a multi-segmented line, distinct from that of flat steel webs. Classic methods may yield significant deviations in predicting the elastic global shear buckling capacity of CSWs of various scales due to their failure to consider real boundary constraints. Therefore, a universally applicable formula for calculating the elastic critical global shear buckling stress of CSWs, which accounts for real boundary conditions, is proposed. This formula is pertinent to both large-scale engineering CSWs and small-scale testing CSWs. This study commenced with a comprehensive reassessment of the elastic global shear buckling calculation method. Subsequently, the influence of geometric parameter ratios on the elastic critical global buckling stress was examined. The primary parameter was identified and employed to improve the global buckling coefficient. The proposed calculation method was validated using different corrugation configurations, including 1000-type, 1200-type, 1600-type, 1800-type, and 2000-type CSWs, as well as other CSWs used in experimental settings. These results were compared with those obtained from other reference methods. Findings indicate that the accuracy of the classic theoretical method is affected by variations in both boundary conditions and geometric dimensions due to the constraint effect of real boundary conditions. Under the real boundary conditions, the elastic critical global shear buckling stress of CSWs with simply supported boundary conditions is close to that of CSWs with consolidated boundary conditions. The ratio of web height to corrugation depth primarily affects the elastic global shear buckling capacity, which decreases as the ratio increases. The Easley formula can be modified based on the web height to corrugation depth ratio. Comparisons of numerous numerical and theoretical results reveal that the proposed calculation method exhibits commendable computational precision. In comparison to alternative formulas, the proposed method demonstrates enhanced consistency for calculating CSWs with varying geometric dimensions and boundary conditions, thereby demonstrating its favorable applicability. These conclusions provide valuable reference for the shear design of CSWs.