Conversion Formula Research Articles

Converting Dependence of Extreme Wind Pressure Coefficients Across Different Epochs

The dependence of extreme wind pressure coefficients has gained attention due to its potential impact on determining design wind loads and assessing wind-induced damages of cladding components. However, experimental data with short durations often fail to provide a sufficient number of extreme samples of pressure coefficients over specified epochs (e.g., 10 minutes or 1 hour). Consequently, estimating the dependence of extreme pressure coefficients remains a challenge. To address this issue, Spearman’s ρ is employed to quantify the dependence of extreme pressure coefficients due to their non-Gaussianity nature, based on which a theoretical formula converting the dependence of extreme pressure coefficients across different epochs is deduced. Furthermore, a simplified conversion formula, which offers accuracy equivalent to the theoretical one while enhancing efficiency, is provided. A dataset of pressure coefficients with a very long duration is employed for formula examination. The conversion formula demonstrates good agreement with the observed trend of dependence between extreme pressure coefficients over different epochs. Error analysis is also conducted to investigate the uncertainty of estimates from data. Additionally, the efficacy of the conversion formula deduced based on Pearson’s linear correlation coefficient is discussed.

‘Converting’ Knowledge, Culture and Themselves

Abstract In this paper, I propose a new model of how the Mongol empire connected the various systems used by the subject peoples under their control. I contrast this to modern empires, which used a system of direct standardisation, so that one calendar, one currency, one system of measures, one way of doing history, often even one language (at least for most public purposes) and so on, was imposed on the entire empire. In the Mongol Empire, while a single system was not imposed, new methods of ‘conversion’ – or perhaps we could say ‘conversion formulae’ – appeared, by which disparate cultural practices of the conquered peoples were maintained, but rendered easily ‘convertible’ to each other, using tables and cognate methods. I discus this ‘conversion’ empire – as opposed to the modern ‘integration’ empire – in the fields of the calendar, language, money and historiography.

Comparative Molecular Docking of Apigenin and Luteolin versus Conventional Ligands for TP-53, pRb, APOBEC3H, and HPV-16 E6: Potential Clinical Applications in Preventing Gynecological Malignancies.

This study presents a comparative analysis of molecular docking data, focusing on the binding interactions of the natural compounds apigenin and luteolin with the proteins TP-53, pRb, and APOBEC, in comparison to conventional pharmacological ligands. Advanced bioinformatics techniques were employed to evaluate and contrast binding energies, showing that apigenin and luteolin demonstrate significantly higher affinities for TP-53, pRb, and APOBEC, with binding energies of -6.9 kcal/mol and -6.6 kcal/mol, respectively. These values suggest strong potential for therapeutic intervention against HPV-16. Conventional ligands, by comparison, exhibited lower affinities, with energies ranging from -4.5 to -5.5 kcal/mol. Additionally, protein-protein docking simulations were performed to assess the interaction between HPV-16 E6 oncoprotein and tumor suppressors TP-53 and pRb, which revealed high binding energies around -976.7 kcal/mol, indicative of their complex interaction. A conversion formula was applied to translate these protein-protein interaction energies to a comparable scale for non-protein interactions, further underscoring the superior binding potential of apigenin and luteolin. These findings highlight the therapeutic promise of these natural compounds in preventing HPV-16-induced oncogenesis, warranting further experimental validation for clinical applications.

Rational [formula omitted] cubic Powell–Sabin B-splines with application to representation of ruled surfaces

This paper defines rational C1 cubic Powell–Sabin splines and analyses their basic properties. A rational B-spline basis is established and an algorithm for determining the corresponding control points and weights by using the blossoming operator is presented. The capability of the introduced splines to represent rational cubic triangular Bézier patches and quadratic NURPS is discussed and explicit conversion formulas are provided. Moreover, the application of the rational C1 cubic Powell–Sabin splines to representation of ruled surfaces is studied, showing that the cubic splines can give smoother parametrizations than the NURPS.

Equivalent conversion of different multiaxial stress rupture criteria for creep materials based on skeletal point stresses

Multiaxial creep life prediction of components has been challenging. To cope with the challenge, efforts have been made to develop suitable multiaxial stress rupture criteria (MSRC) based on representative stress concept. Of all MSRCs, the ones due to Sdobyrev and Hayhurst-Leckie (denoted as SHL MSRC), and to Cane (denoted as Cane MSRC) are commonly-used. In this work, the equivalent conversion between the SHL MSRC and the Cane MSRC is investigated based on skeletal point stresses. Equivalent conversion formulae are proposed based on the skeletal point stresses of circumferentially-notched tension (CNT) specimen, and then validated by comparison with the experimental data available in the literature. The equivalent conversion formula between the two MSRCs is found to be dependent on the signs of principal stresses. Therefore, different conversion formulae should be chosen depending on the signs of principal stresses. Afterwards, the applicability of different equivalent conversion formulae is demonstrated for the CNT specimen when skeletal point stresses are available, and for creep crack growth specimen when skeletal point stresses are not available. Finally, the equivalence of the two MSRCs is discussed.

Open, Active-Controlled Clinical Study to Evaluate the Correlation between Whole Body DEXA and BIA Muscle Measurements.

Dual energy X-ray absorptiometry (DXA) is the gold standard for diagnosing sarcopenia. However, comparative studies using bioelectrical impedance analysis (BIA) would be required in the Korean population. This study aimed to evaluate the correlation between total-body bone density measuring devices (Hologic and GE Lunar) and a bioelectrical impedance measurement device (InBody 970) as well as the correlation between upper body muscle mass. A total of 119 participants were involved in this study, aged 20 to 70 years, with specific body mass index ranges and no severe health conditions used both DXA (or DEXA) and BIA technologies to assess body composition. The participants were scanned using a Hologic QDR-4500W DXA scanner and GE-Lunar Prodigy DXA systems, and the InBody 970 type of multi-frequency BIA machine. Statistical analysis was performed to determine the correlation between the devices, with a coefficient of at least 0.8. The muscle mass measurement comparisons between the InBody 970 and Hologic devices demonstrated remarkably high correlation coefficients (exceeding 0.9) across all limbs. Similarly, the muscle mass comparison between the Inbody 970 and GE Lunar devices also revealed substantial correlation coefficients, ranging from 0.83 upwards, across all limbs. Limb muscle mass measurements using Hologic and GE Lunar whole-body DXA and Inbody 970 BIA demonstrated particularly high levels of concordance. In addition, a conversion formula that bridges limb muscle mass measurements from two widely used whole-body DXA machines and a BIA machine will facilitate sarcopenia research and patient management.

Investigation on the dynamic failure characteristics of concrete slab based on mesoscopic simulation and energy conversion analysis

In this study, Continuous Discontinuous Element Method (CDEM) was employed to analyze the failure of concrete slab under drop-hammer impact at the mesoscopic level. Initially, simulation models of the impact system were established, and concrete slab models, including three-dimensional random aggregates, were generated. Mesoscopic simulations of concrete failure were then conducted by considering different variables, such as impact energy, slab size and the number of hammerheads. Corresponding drop hammer tests were used to validate the simulation results. Furthermore, an energy conversion formula for the dynamic failure of concrete slabs was derived, and the energy conversion process within the impact system was analyzed. The study also revealed the dynamic failure mechanisms of concrete slabs under various impact conditions. The research demonstrates that the simulation results are generally consistent with the impact tests. CDEM effectively investigates the impact characteristic and the energy conversion process of concrete slab failure. Under varying impact energies, slab sizes and hammerhead numbers, distinct differences in the failure characteristics of concrete-slab structure were observed. Increased impact energy accelerates the failure of concrete slabs, whereas larger concrete slab sizes inhibit crack propagation. The number of impact heads determines the initial crack position and its propagation path within the concrete slab. Moreover, the energy conversion process of the impact system significantly influences the failure behavior of the concrete slab. The effect of slab size on the energy utilization rate is greater than those of hammerhead number and impact speed.

Preparation and properties of strong gamma ray shielding and irradiation resistant glass

CeO2 doped lead silicate glasses samples were prepared by high temperature melting method. The structural, thermal and optical properties of the glasses were characterized by density, expansion coefficient, XPS and ultraviolet-visible spectroscopy. Additionally, the related theoretical work was carried out for verification. The changes in structure and optical properties of the glass before and after irradiation were investigated. The influence mechanism of different content of CeO2 (PbO) on the structure and properties of shielding glass was discussed. By comparing the three transmittance conversion formulas, it is found that the characteristic coefficient can be further calculated if the transmissivity with varied thicknesses is known. This coefficient method allows for accurate calculation of transmittance for glasses with arbitrary thicknesses while demonstrating experimental validation. The accuracy improves as more measured values of transmittance for glasses with different thicknesses are obtained and as more iterations of characteristic coefficients are performed. This method is suitable for both scientific research and production practice. The test results show that the transmittance of the glass with 45 wt% PbO and 2 wt% CeO2 content is above 60 % in the wavelength range of 400–800 nm before irradiation and decreased less than 10 % after irradiation. The measured shielding rate of 60Co gamma rays can reach more than 51 %. The calculated transmittance of 300 mm thickness glass is greater than 50 %. The superior gamma ray shielding capability along with its radiation resistance make this glass provide key support for window materials used in various fields such as nuclear industry, aerospace, military and medicine.

Accuracy analysis of UAV aerial photogrammetry based on RTK mode, flight altitude, and number of GCPs

Abstract The optimization of an unmanned aerial vehicle (UAV) aerial photogrammetry scheme is crucial for achieving higher precision mapping results. Three representative factors, namely the real-time kinematic (RTK) mode, flight altitude, and the number of ground control points (GCPs) were selected to analyze their impact on UAV aerial photogrammetry accuracy. Four flight altitude tests were conducted separately in two RTK modes, and five GCP layout schemes were designed. Based on this, the root mean square error (RMSE) values of 40 aerial photogrammetric results were analyzed. The results showed a significant correlation between flight altitude and resolution of the UAV aerial photogrammetric results. Further, conversion formulas between actual image resolution and flight altitude for different GCP values were also derived in RTK and non-RTK modes. In the case of precise positioning, the horizontal and vertical accuracy of the aerial photogrammetric image decreased with increasing flight altitude. Under the same flight altitude, the addition or no addition of GCPs, including changes in GCP numbers, had no significant effect on improving the accuracy of aerial photogrammetry in RTK mode. However, in non-RTK mode, the number of GCPs significantly affected accuracy. The horizontal and vertical RMSE values decreased rapidly with the increase in GCP numbers and then stabilized. However, regardless of whether RTK was activated, an excessive number of GCPs was not conducive to improving the accuracy of aerial photogrammetric results. The mapping accuracy of UAVs in RTK mode without GCPs was equivalent to that in non-RTK mode with GCPs. Therefore, when using RTK-UAVs, deploying GCPs is unnecessary under suitable circumstances. Finally, practical suggestions for optimizing the UAV aerial photogrammetry scheme are provided as a reference for related applications.

Test and analysis of energy characteristics of large vertical submersible pumps

The efficiency of the pump device is an important parameter to judge the overall dynamic performance of the pumping station. The commonly used method at home and abroad is to carry out model tests of the pump device. The performance parameters of the prototype pump and pump device are obtained by the similarity conversion formula. However, at present, there are not many device model tests for large vertical submersible pumps. Taking a large vertical submersible mixed-flow pumping station in China as an example, research predicted the performance of the pump device through a model test and a submersible pump prototype test. The results show that the model test of the large vertical submersible mixed-flow pump device has a maximum efficiency of approximately 77.8%, and the prototype test conversion device has a maximum efficiency of approximately 80.33%. The device model test and the pump factory prototype test results are compared. It is found that the performance parameters of the pump measured by the prototype test are in good agreement with the device model test under the design conditions, and there is a certain error when the deviation from the design conditions is significant. The device model test and the factory test of the pump are indispensable in the large-scale road of submersible pumps, and a large number of tests are needed to sum up the experience.

Comparison of whole-blood sirolimus concentrations measured by EMIT-based Siemens Viva-ProE® System and LC-MS/MS in Chinese transplant patients

Sirolimus (SRL) is commonly used in transplant patients to prevent organ transplant rejection. The current guidelines recommend to perform SRL therapeutic drug monitoring regularly to improve treatment outcomes and avoid adverse effects. Consequently, a precise and accurate method for determining SRL is crucial in clinical practice. Currently, liquid chromatography–tandem mass spectrometry (LC-MS/MS) and immunoassays have been widely adopted for determining SRL concentrations. However, previous studies have shown that immunoassays exhibit a positive bias compared to LC-MS/MS. As the new updated version of the EMIT-based Viva-E® System (SVPS), this study aims to compare SRL blood concentrations measured by the SVPS and LC-MS/MS. The residual whole-blood samples obtained from transplant patients were simultaneously analyzed using the SVPS and LC-MS/MS, respectively. The correlation between the two assays was analyzed using the linear regression analysis and Deming linear regression. The Pearson correlation coefficient and Intraclass correlation coefficient (ICC) analysis were executed. The Paired Wilcoxon test and Bland-Altman analysis were performed to assess the concordance between the two methods. The SVPS considerably increased SRL concentration value by 46.62 % as compared to the LC-MS/MS method. When SRL concentrations measured by the SVPS were above 4.0 ng/mL, there was no significant difference between the corrected SVPS concentrations after using the Deming linear regression equation, indicating their interchangeability. Given the significant disparities observed between EMIT and LC-MS/MS, it is crucial to indicate the methodology and instruments in both TDM reports and future clinical guidelines. Our study also provides the conversion formulas between the SVPS and LC-MS/MS, which can be applied as a reference for different clinical centers.

Robotic Arms for Telemedicine System Using Smart Sensors and Ultrasound Robots

Given the global population ages, the traditional medical system must change. Our telemedicine system combines the devices with sensors. Our telemedicine system is a new type of medical application. In this paper, we systematically integrate the force sensor, robot arm, optical radar device, and jelly mechanism to develop a telemedicine application system. We used a three-dimensional coordinate conversion formula to convert the coordinates of each axis of the robot arm into the coordinates of the smartphone so that the doctor can control the robot arm remotely using the smartphone. The force sensor embedded in the robot arm provides transparency to the doctor during operation, enabling them to monitor whether the force applied by the robotic arm on the human body is excessive. In addition, through the jelly mechanism installed on the robot arm, the doctor only needs to use a smartphone to control the jelly mechanism to achieve remote control needs. The experimental testing results sufficiently show the practicability of our scheme for telemedicine.

Laboratory-accelerated simulation and calibration method for ultraviolet aging of asphalt binders based on radiation equivalent conversion

Ultraviolet (UV) radiation is a significant environmental factor that accelerates the aging of asphalt pavements. To address the gap in the equivalence conversion relationship between laboratory simulation parameters and field environmental factors for asphalt pavement aging in the Tibet area of China, this study investigates the relationship between laboratory simulations and field service for asphalt aging. The results indicate that using macroscopic rheological parameters (rutting factor (G*/sin δ), average recovery rate (R), and average non-recoverable creep compliance (Jnr)) and microscopic parameters (sulfoxide index (SI) and glass transition temperature (Tg)) as quantitative indicators can evaluate the equivalent degrees of laboratory and field aging. Furthermore, this study introduces a correction coefficient for laboratory-accelerated simulated aging to improve the accuracy of the equivalent radiation conversion formula. The correction coefficient range for 90# matrix asphalt is 1.36–2.05, while the range for SBS modified asphalt is 0.82–1.64. This study provides a valuable database for establishing the relationship between laboratory simulations and field service for asphalt aging and offers a parameter basis and technical support for designing durable asphalt pavements in areas with intense UV radiation.

DOxy: A Dissolved Oxygen Monitoring System.

Dissolved Oxygen (DO) in water enables marine life. Measuring the prevalence of DO in a body of water is an important part of sustainability efforts because low oxygen levels are a primary indicator of contamination and distress in bodies of water. Therefore, aquariums and aquaculture of all types are in need of near real-time dissolved oxygen monitoring and spend a lot of money on purchasing and maintaining DO meters that are either expensive, inefficient, or manually operated-in which case they also need to ensure that manual readings are taken frequently which is time consuming. Hence a cost-effective and sustainable automated Internet of Things (IoT) system for this task is necessary and long overdue. DOxy, is such an IoT system under research and development at Santa Clara University's Ethical, Pragmatic, and Intelligent Computing (EPIC) Laboratory which utilizes cost-effective, accessible, and sustainable Sensing Units (SUs) for measuring the dissolved oxygen levels present in bodies of water which send their readings to a web based cloud infrastructure for storage, analysis, and visualization. DOxy's SUs are equipped with a High-sensitivity Pulse Oximeter meant for measuring dissolved oxygen levels in human blood, not water. Hence a number of parallel readings of water samples were gathered by both the High-sensitivity Pulse Oximeter and a standard dissolved oxygen meter. Then, two approaches for relating the readings were investigated. In the first, various machine learning models were trained and tested to produce a dynamic mapping of sensor readings to actual DO values. In the second, curve-fitting models were used to produce a successful conversion formula usable in the DOxy SUs offline. Both proved successful in producing accurate results.

Visual and machine strength gradings of Scots and red pine structural timber pieces from Türkiye

Scots (Pinus sylvestris L.) and red pine (Pinus brutia Ten.) structural timbers (540 pieces) from Türkiye were first visually graded according to TS 1265 (2012). Then, non-destructive tests were conducted using vibration and time of flight (ToF) methods, followed by destructive tests on a four-point bending test setup according to EN 408 (2012). The vibration method showed a higher correlation than ToF with strength and stiffness. The dynamic modulus of elasticity (MOEd) obtained by the vibration method was 12.3% and 15.4% lower in Scots and red pine, respectively, compared to the ToF method. Mechanical testing determined local MOE was 14% and 15% higher than global MOE for Scots and red pine, respectively. An alternative formula to the existing conversion formula in EN 384 (2018) was derived. The average bending strength of red pine was 7% higher than Scots pine. For visual strength grading, local and global MOE in Scots pine, class 1, 2, and 3 structural timbers were assigned to C35, C27, and C22, respectively. Red pine was assigned to C40, C27, and C24 for local MOE and C35, C24, and C22 for global MOE. In machine strength grading, the grade combination was C40-C30-C22-C16-R for both species. The best results were achieved in settings where vibration method and local MOE were used together. Machine strength grading achieved higher efficiency than visual strength grading.

Optimal temperatures for measuring oil viscosity to restore its viscosity-temperature dependence according to the Filonov–Reynolds, Walter and Vogel–Fulcher–Tamman formulas

Relevance. Increase in the number of high-viscosity and non-Newtonian oils produced and transported. For such oils, it is important to accurately predict the rheological properties and, in particular, the viscosity-temperature dependence. Viscosity measurement for a wide range of different temperatures is excessively time-consuming and irrational, and in practice, viscosity measurement is used at two or three different temperatures and then conversion formulas are used. It is also important to clarify, which formulas and for which oils should be used to obtain the smallest error. It is important, in particular, to determine the optimal temperatures for measuring the viscosity of oil to restore its viscosity-temperature dependence. Aim. To determine the optimal temperatures for measuring oil viscosity to restore its viscosity-temperature dependence using the Filonov–Reynolds, Walter and Vogel–Fulcher–Tamman formulas, including when calculating for the entire available temperature range. Objects. Viscosity-temperature dependences of oils from the Directory of oils of the USSR. Methods. Processing the viscosity measurement data for 564 oils from the USSR Oil Directory; construction of approximating viscosity-temperature dependencies; determination of error when using the obtained dependencies, including using cross-validation. Results. The authors have calculated the error in application of the Filonov–Reynolds, Walter, Vogel–Fulcher–Tamman formulas, using over 500 oils as an example. It was found that with a random choice of temperatures for measuring viscosity, the minimum average error at another temperature for these formulas is, respectively, 13.8, 10.7 and 6.2%. The use of the Filonov–Reynolds formula is undesirable for calculating viscosity at low temperatures. The Vogel–Fulcher–Tamman formula shows the best results in calculating viscosity when using temperatures of 30–50–70 and 10–30–50°C.

Nanowire sensor calibration and performance evaluation in microfluidic flow velocity monitoring

A microfluidic chip, integrated with a contact flow velocity sensor, was fabricated. A single gold nanowire prepared by nanoskiving was positioned across the bottom of a microfluidic channel. Real-time monitoring of the microfluidic flow velocity is achieved by leveraging the principle of forced heat exchange between the fluid and the solid nanowire. To harmonize theoretical calculations and experiments, leading to the derivation of a conversion formula between the flow equivalence factor and the flow velocity. Analysis of experimental data, specifically curves of resistance versus time, yields two characteristic parameters for the nanowire sensor: the step size of the flow equivalence factor and the resistivity variation. The performance of nanowire sensor was further analyzed by examining the patterns exhibited in the relationship between characteristic parameters (resolution and response characteristics) and both voltage and inlet flow rate. This work has potential applications in biomedical sensing, microfluidic mixing, and other areas where flow velocity control is required.

Quantification of Aortic Valve Calcification in Contrast-Enhanced Computed Tomography.

Background: The goal of our study is to evaluate a method to quantify aortic valve calcification (AVC) in contrast-enhanced computed tomography for patients with suspected severe aortic stenosis pre-interventionally. Methods: A total of sixty-five patients with aortic stenosis underwent both a native and a contrast-enhanced computed tomography (CECT) scan of the aortic valve (45 in the training cohort and 20 in the validation cohort) using a standardized protocol. Aortic valve calcification was semi-automatically quantified via the Agatston score method for the native scans and was used as a reference. For contrast-enhanced computed tomography, a calcium threshold of the Hounsfield units of the aorta plus four times the standard deviation was used. Results: For the quantification of aortic valve calcification in contrast-enhanced computed tomography, a conversion formula (691 + 1.83 x AVCCECT) was derived via a linear regression model in the training cohort. The validation in the second cohort showed high agreement for this conversion formula with no significant proportional bias (Bland-Altman, p = 0.055) and with an intraclass correlation coefficient in the validation cohort of 0.915 (confidence interval 95% 0.786-0.966) p < 0.001. Conclusions: Calcium scoring in patients with aortic valve stenosis can be performed using contrast-enhanced computed tomography with high validity. Using a conversion factor led to an excellent agreement, thereby obviating an additional native computed tomography scan. This might contribute to a decrease in radiation exposure.

Optimization of leaf area index measurement method and correction of green plot ratio formula based on regional plant characteristics-a study in Chongqing, China.

The quantification of green space green plot ratio (GPR) is mostly based on estimation formulas, and the leaf area index (LAI) estimation values in these estimation formulas have not been well verified by measured LAI values, resulting in errors and uncertainties in GPR quantification results. This study aims to address this gap by measuring the LAI of 113 regional plants in Chongqing, China, following a standardized measurement path for digital hemispherical photography (DHP). The results indicate that the optimal relative exposure value (REV) was - 1 under overcast conditions and - 2 under sunny and cloudy conditions. Among the threshold algorithms for hemispherical images, the Intermodes algorithm in ImageJ was the best. The LAI of regional plants is highest in summer, followed by spring and autumn, and lowest in winter. Tree height (h) and crown width (w) are key factors affecting LAI, but the LAI also varies with plant species. Overall, the LAI of evergreen trees is higher than that of deciduous trees. The LAI of evergreen trees and shrubs with a height shorter than 5m is the largest, and that of deciduous trees and shrubs with a crown width larger than 8m is the largest. The study further verified that the existing GPR estimation formula exhibited large errors in Chongqing, while there was a strong correlation (R2 = 0.973) between the GPR estimation value and the measured value. A conversion formula was developed to reduce estimation biases, and the corrected formula is capable of estimating GPR values more accurately when actual LAI measurements are insufficient. Overall, this study verifies the significance of measuring localized LAI values, promotes the understanding of LAI suitability for GPR calculations, and provides an empirical formula for GPR estimation in Chongqing, China.

Normalized frequency for noncircular dielectric waveguides

AbstractThis paper points out that the commonly used normalized frequency for noncircular dielectric waveguides, which is based on the semiminor axis, causes the cross‐sectional area to vary with the cross‐sectional shape. Consequently, the shape effects described with the conventional normalized frequency are not due to the shape alone but the combined effects of the shape and area. Our numerical results show that the area effect is greater than the shape effect. An improved definition of normalized frequency based on an equivalent radius is proposed in this paper. Conversion formulas to convert from the conventional normalized frequency to the proposed normalized frequency are provided for elliptical and rectangular waveguides. Our numerical results show that the shape effects described by the proposed normalized frequency are free from the area effect. Consequently, the proposed normalized frequency is more accurate than the conventional normalized frequency in describing the shape effect of noncircular dielectric waveguides.