Empirical Model for Moon Sighting

Spatial variation of soil thickness, cohesion and friction angle are crucial in large scale slope stability analysis. However, determination of these parameters is challenging, costly and time consuming. In order to opt out expensive laboratory tests and laborious field investigation, efforts had been done by many researchers to predict these parameters over large areas. In this study, the soil samples and soil thickness data are gathered from 30 sampling boreholes and 60 probed points in an area with Pliocene-Pleistocene geology. The details on slope angle are obtained from the slope map through a processed Digital Elevation Model (DEM) in Geographic Information System (GIS) particularly the ArcGIS software. Slope angles are confirmed in the site through actual measurement using the clinometer. The soil thickness is measured from the ground surface down to the interface of soil and weathered bedrock. The cohesion and friction angle are determined from the direct shear test. Regression analysis is used to establish an empirical model
 correlating the soil thickness and shear strength parameters with the slope angle. The result revealed that the slope angle has yielded better correlation to the soil thickness than the cohesion and friction angle. The resulting slope angle-soil thickness empirical model is validated from ten different sites with similar geology.

This paper develops an intuitive empirical nonlinear dynamic shock absorber model for simulation studies. Unlike other existing dynamic shock absorber models, it does not suffer from the complexity of modelling complex physical behaviour, or the inefficiencies of unstructured black-box modelling. The model consists of an algebraic backbone, which is a function of velocity alone, and a nonlinear low-pass filter, which has been designed based on the observation that the damper can respond more quickly at higher velocities. Due to the simplicity of the model, it can be fitted with data and evaluated quickly. The model was fitted using shock dynamometer test data using a random shock position command. The completed model is then validated using random, sine wave, and bump test data. This analysis shows the strengths and weaknesses of the model and suggests areas for future development.

Using ambient concentrations as proxy for methane flux measurements from rice fields

In laser–metal processing such as Laser-based Powder Bed Fusion of Metals (PBF-LB/M), the quality of the final product is significantly influenced by the thermal behaviour of the melt pool. Accurate temperature measurements are challenging due to high temperature gradients and rapid cooling. This study introduces Multispectral Imaging (MSI) as a highly effective thermometry technique to address these demanding conditions. MSI captures multiple bands of radiation, enabling the simultaneous determination of absolute temperature and surface emissivity. This capability is crucial for ensuring high-quality outcomes in laser–metal processing such as PBF-LB/M, contingent upon robust radiometric calibration.To enhance reliability, two radiometric calibration models were developed: an empirical model based on linear sensor data correlations and an analytical model leveraging sensor behaviour. An efficient calibration was found for both models across a range of signal-to-noise ratios in the black body calibrator, where the analytical model even performs robust under a high noise level.Additionally, the temperature accuracy in the solid-state case was tested with a thermo-mechanical simulator. Results showed that the empirical and analytical models achieved mean relative errors of 2.0% and 1.6%, respectively, outperforming the state-of-the-art. Further, laser irradiation experiments highlighted the analytical model’s ability to accurately determine the emissivity decrease during the solid-to-liquid transition, allowing for accurate melt pool temperature estimations. Conversely, the empirical model struggled to estimate temperature effectively in the liquid phase.This study not only proposed a robust methodology of MSI in temperature measurement but also confirmed the accuracy and reliability of the system, broadening the scope for further investigation into the intricate thermal dynamics involved in laser–metal interactions.

An analytical model to predict the velocity-dip-position is presented in this study. Unlike the previous studies where empirical or semiempirical models were suggested, in this study the model is derived by using entropy theory. Using the principle of maximum entropy, the model for dip-position is derived by maximizing the Shannon entropy function after assuming dimensionless dip-position as a random variable. No estimation of empirical parameter is required for calculating dip-position from the proposed model. The model is capable of predicting the velocity-dip-position at any section from sidewall region (along lateral direction) of an open channel with any aspect ratio. The ratio of mean to maximum value of dip-position is analyzed from data, and it is found that ratio is almost constant for narrow open channels and it increases with aspect ratio for wide open channels. A relation is also proposed to predict this ratio in case of wide open channels. The developed model of velocity-dip-position is tested with existing experimental data for a wide range of aspect ratio and is also compared with other empirical models. The present model shows good agreement with the observed data and is comparable with the existing models.

Highly accurate measurements of the amount of substance of organic molecules in a test material can be obtained using exactly matched calibration solutions and internal standards that are labeled with stable isotope atoms by measuring the amount ratio of analyte to internal standard using mass spectrometry. Estimating the uncertainty of quantitative measurements of organic molecules is a means of evaluating accuracy and of establishing traceability to the International System of Units (SI) and requires a measurement function that fully describes the measuring system. This paper presents the derivation of the equation (measurement function) that describes this complete measurement after the internal standard has equilibrated with the test material matrix. It is similar to the equation for inorganic measurements using isotope dilution techniques, but potential biases during chemical processing arising from whole organic molecule analysis compared to inorganic atomic analysis required greater investigation of the yield factors that occur during organic molecule measurements. In the new equation, a series of ratios of proportionality factors are used to relate the amount of substance in a test material to chromatographic peak area ratios corresponding to mass spectrometer ion current ratios. All the proportionality factors are grouped together to define a measuring system factor F(X), the value of which is determined by the fundamental chemical processes affecting the yields of analyte, internal standard, and reference standard of the analyte in the measurement process. Any factors in the measurement process that affect the mole ratio of analyte to internal standard in the calibration solution differently from the test solution will result in a nonunity value for F(X) and a proportional bias to the measurement, and in this way F(X) represents the concept of recovery of the amount ratio of analyte to internal standard. Thus highly accurate measurements require F(X) or its constituent factors to be evaluated. In addition, the uncertainty in the evaluation of F(X) or of its constituent factors must be included in a complete uncertainty estimation of the analytical procedure. The many different permutations of proportionality factor ratios that may result in a unity value of F(X) are discussed resulting in a case for evaluating F(X) rather than the more common practice of evaluating individual factors for each major stage of the measurement procedure. Since the new measurement function describes the complete chemical process that constitutes the measurement, traceability to the SI is assured when all factors in the function are measured traceably and have their associated uncertainty estimated correctly. Ignoring F(X) would invalidate traceability to the SI and would prevent a complete estimation of measurement uncertainty.

Estimation and validation of daily global solar radiation by day of the year-based models for different climates in China

The aim of this study is to establish the estimation method of body parameter using wearable sensor system. The wearable motion sensor installs gyro sensor, acceleration sensor and magnetic field sensor, and this sensor outputs angular velocity, acceleration and magnetic field. The output of acceleration sensor attached to body segment includes the centrifugal and tangential acceleration components, and these components include the position vector from the joint to the sensor. The proposed method estimates the position vector from the joint to the sensor by using the output of wearable motion sensor. Furthermore, the position vector is focused the component of 1-axis direction. We conducted the measurement experiment of bending exercises by a subject attaching the wearable motion sensors. The position vector from foot joint to the motion sensor attaching to lower thigh is estimated. The position vector indicated the similar result against the length measured using other method. We indicated that the proposed method can use in actual body motion measurement. Therefore, the method can be used for the development of more simply motion measurement method in the motion analysis using wearable motion sensor.

Radial pressure profile of typhoon field near ground surface observed by distributed meteorologic stations

A real-time airborne synthetic aperture radar requires accurate measurement of the antenna at high and low frequencies to produce well-focused images with minimal target location errors. Sandia National Laboratories achieves accurate motion measurement by updating a navigation solution derived from an inertial measurement unit with global positioning system measurements via a unique Kalman filter. An overview of the motion measurement design and implementation is presented for the Lynx and Rapid Terrain Visualization radars, as well as results from a variety of experiments.

When applying radio-frequency (RF) techniques to measure and monitor partial discharges (PD), the CIGRE ‘sensitivity verification’ recommendation details a methodology for achieving a specified equivalent PD charge sensitivity for the combination of RF PD sensors and the measurement or monitoring system installed in a gas-insulated substation (GIS). The recommendation allows some flexibility in the GIS set-up used to perform the test. For the work covered in this paper, second in a series, a CIGRE step 1 laboratory test was conducted using an ‘L’ -shaped section between sensors 'C1' and 'C2', in order to present a more challenging propagation path between them. RF network analyzer (RFNA) measurements and finite-element modeling (FEM) were performed on the section and compared. The RF propagation properties of GIS sections with similar topologies in both lab and field were investigated through both models and measurements and these results compared with prior work in the field. Refinements to FEM modeling techniques result in a closer match to actual measurements, but an exact match probably remains out of reach. We discuss these results and our recent observations, the implications for PD sensor placement to satisfy the CIGRE recommendation, and outline anticipated next steps.

In the present work a precise but simple empirical model for single gate nanoscale single-layer fully depleted strained-silicon-on-insulator MOSFET is proposed. The threshold voltage is calculated by solving the two-dimensional (2D) Poisson equation under befitting boundary conditions incorporating short-channel effects, the effect of strain, strained-silicon thin film thickness, and gate work function. The proposed empirical model provides results comparable with those obtained from 2D device simulation thereby establishing the extent of accuracy of our present model. The empirical model so developed correctly exhibits that the threshold voltage is reduced with the increase of strain in the silicon thin film. We have investigated, herewith our proposed model, the influences of various device parameters like: strain (with minute amount of carbon and significant amount of Ge), strained-silicon thin-film thickness and gate work function on the threshold voltage. The extent of equivalent Ge content enhances the performance of the proposed MOSFET in terms of better speed because of the carrier mobility enhancement due to addition of carbon atoms.

The objective of this investigation was to develop a dimensionless model for predicting the onset of cavitation in torque converters applicable to general converter designs. Dimensional analysis was applied to test results from a matrix of torque converters that ranged from populations comprised of strict geometric similitude to those with more relaxed similarities onto inclusion of all the torque converters tested. Stator torque thresholds at the onset of cavitation for the stall operating condition were experimentally determined with a dynamometer test cell using nearfield acoustical measurements. Cavitation torques, design parameters, and operating conditions were resolved into a set of dimensionless quantities for use in the development of dimensionless empirical models. A systematic relaxation of the fundamental principle of dimensional analysis, geometric similitude, was undertaken to present empirical models applicable to torque converter designs of increasingly diverse design parameters. A stepwise linear regression technique coupled with response surface methodology was utilized to produce an empirical model capable of predicting stator torque at the onset of cavitation with less than 7% error for general automotive torque converter designs.

For a complete understanding of a wave energy conversion device, it is important to know how the proposed device moves in the water, how this motion can be measured, and to what extent the motion can be predicted or simulated. The magnitude and character of the motion has impacts on engineering issues and optimization of control parameters, as well as the theoretical understanding of the system. This paper presents real sea measurements of buoy motion and translator motion for a wave energy system using a linear generator. Buoy motion has been measured using two different systems: a land-based optical system and a buoy-based accelerometer system. The data have been compared to simulations from a Simulink model for the entire system. The two real sea measurements of buoy motion have been found to correlate well in the vertical direction, where the measured range of motion and the standard deviation of the position distributions differed with 3 and 4 cm, respectively. The difference in the horizontal direction is more substantial. The main reason for this is that the buoy rotation about its axis of symmetry was not measured. However, used together the two systems give a good understanding of buoy motion. In a first comparison, the simulations show good agreement with the measured motion for both translator and buoy.

This paper presents robust empirical path loss models to characterize indoor propagation for access point (AP) deployed at different heights. The proposed models are developed with wireless local area network infrastructure at 2.4 GHz. The models are backed by extensive received signal strength (RSS) measurements acquired in line of sight and obstructed line of sight regions. The models are developed for two conditions, viz; quasi realistic and realistic RSS measurements. The quasi realistic measurements are taken after suppressing human intervention and electrical interferences to minimum. While the realistic RSS measurements are made in presence of all the human interventions and electrical interferences. The shadow fading component for both quasi realistic and realistic conditions is statistically modeled with the dependency on AP height. The proposed technique can be applied with higher confidence level to the buildings with similar construction features where RSS measurements are made upon. The results reveal that the performance of the proposed propagation models is significantly higher than the existing International Telecommunication Union-path loss model. The results also demonstrate that the realistic path loss model is more robust than the quasi realistic model.