Empirical Coefficients Research Articles

The Relationship between Self-Awareness and Humility in Generation Z in Kayuroya Village, Minahasa Regency

Generation Z is a generation that has grown up in an era of rapid modern technology. This has triggered changes in the way Generation Z thinks and acts, including in terms of values and character. Self-awareness and humility are two characters that are considered important to build in shaping a good personality in generation Z. This study aims to determine the relationship between self-awareness and humility in generation Z in Kayuroya village, Minahasa Regency. This study used a quantitative approach. The population amounted to 90 people by looking at the Isaac and Michael sample size determination table for an error rate of 10%, the sample amounted to 68 people. Self-awareness was measured using an awareness scale based on Brown and Ryan's (2003) theory or The Mindful Attention Awareness Scale (MAAS). Humility was measured using the humility scale from Jeffrey Charles Elliott (2010). Based on the research conducted, it is concluded that there is no relationship between self-awareness and humility in generation Z in Kayuroya village, Minahasa Regency where the empirical correlation coefficient (rxy) value is 0.397 ≥ 0.05 and the rcount value is -0.032 0.239. The percentage of self-awareness and humility in generation Z in Kayuroya village, Minahasa Regency is at a low level, where there are 42 respondents (61.8%) low self-awareness and 26 people (38.2%) high self-awareness, and 37 respondents (54.4%) low humility and 31 people (48.6%) have high humility

Laboratory Innovation to Investigate Concrete Paving Blocks Compressive Strength

This research aims to evaluate the block method against the cube test method using variations in thickness. Paving blocks can be produced using a hydraulic machine or a simple press, and their performance can be measured based on density and compressive strength tests. The block test method shows that with the same material composition forming the paving block, a paving block with a higher thickness can lead to a lower compressive strength value. In contrast, the cube test method shows different results. The paving blocks used in this study had width and length sizes of 100 and 200 mm, respectively, and had varying heights of 60, 80, and 100 mm. The results reveal that the compressive strength of concrete paving blocks is more precise based on density. Furthermore, the empirical equation and conversion coefficient of the compressive strength of the block test to the cube test have been obtained. This empirical equation is highly recommended for the road pavement industry in controlling the quality of compressive strength, even when using block tests. Further research can help develop a formula for using additive materials in paving blocks. Doi: 10.28991/CEJ-2023-09-11-03 Full Text: PDF

Research to establish the equation of the principle of claystone breaking under the seabed

The rule of breaking rock has practical significance in the process of controlling the blasting for the optimization of mine production or construction of blasting works. The equations describing the particle size distribution after the explosion are established in an experimental form corresponding to the specific conditions of the blasting work. It only has the meaning of a mathematical regression function and does not reflect the characteristics of the rock type, explosive conditions and explosive results. This research has exploited the theory of rock breaking from the point of view of probabilistic energy to establish the equation of rock breaking of claystone in water. This is a form of semi-empirical equation, which contains 4 empirical coefficients reflecting rock characteristics, explosive conditions, explosive energy absorption characteristics of rocks and actual destruction volume, determined for each type of rock. Through conducting experiments, processing experimental data and solving a system of four equations, four coefficients of the equations that characterize the breaking properties of claystone under the seabed have been found. The error of the average particle size between the actual and calculated values from the equations is less than 7% to 10%. Tt is possible to confirm the accuracy of the semi-empirical equation describing the particle size distribution rule when the claystone is exploded underwater.

Influence of neuromuscular electrical stimulation pulse waveform on corticomuscular coupling and the brain functional connectivity network

ObjectiveNeuromuscular electrical stimulation (NMES) has been shown to promote functional corticomuscular coupling (FCMC), but its effect on brain functional connectivity network (BFCN) remains uncertain. This study aims to propose a new method to analyze the influence of NMES with different stimulation waveforms on the motor system from two perspectives of FCMC and BFCN. ApproachThe bivariate empirical mode decomposition time-delay maximal information coefficient (BTDMIC) method was used to assess the local frequency band characteristics of the cortex and muscle. Main resultThe experimental results showed that the FCMC increment after NMES was prominent in the β1 (15–25 Hz), β2 (25–35 Hz), and γ1 (35–45 Hz) bands. Additionally, the coupling values of C3 after sine-NMES were highest in the β1 band, while the coupling values after square-NMES were highest in the β2 and γ1 bands. For BFCN, the cortical-cortical coupling of the C3 after square-NMES was high in the C3 → others direction. Moreover, in the α (8–14 Hz) and β1 bands, the clustering coefficient, density, and efficiency after square-NMES were significantly higher than those of the three other frequency bands. ConclusionNMES effectively promoted information exchange between the motor cortices of the brain, and the facilitating effect is particularly pronounced in the case of square-NMES. SignificanceThis study offers a novel perspective for evaluating rehabilitation therapies based on NMES.

Integrated effects of land use and land cover change on carbon metabolism: Based on ecological network analysis

Faced with increasingly severe climate change, assessing integrated effects of Land use and land cover (LULC) changes on carbon metabolism contributes to the understanding of the mechanism of LULC‑carbon interactions and is crucial to enhance the benefits of anthropogenic emission reductions, increasing regional carbon sinks and formulating future mitigation policies. In this paper, we have developed a hybrid analytical framework that couples natural and socioeconomic systems, and used socioeconomic data, high-resolution remote sensing data, and empirical coefficients to analyze spatiotemporal dynamics of carbon metabolism and applied ecological network analysis (ENA) to evaluate integrated effects of LULC changes upon carbon metabolism. We used Gansu Province, an economically underdeveloped region, as an example for case analysis and policy recommendations. The results showed that: (1) the total carbon emissions in Gansu increased 3.18 times between 1995 and 2020, with transportation and industrial land being the major contributors. The carbon balance status was increasingly severe, and the amount of carbon sequestration to offset carbon emissions decreased from 22.45% in 1995 to 7.11% in 2020. (2) ENA revealed that competition relations between land use types fluctuated up and dominated in 2020, with the mean value of mutualism index was 0.72, which suggested that that integrated effects of LULC changes on whole regional carbon metabolism was negative. Compared to developed regions, the ecological relationships between different land use types in Gansu were more competitive. (3) To address these issues, we have proposed comprehensive policies in terms of adjusting industrial structure, reducing fossil energy use, saving land for construction, and developing carbon sink industries. The study explored the intricate interactions between LULC changes, carbon transition, and regional carbon metabolism in underdeveloped region, and its framework and findings provide insights and recommendations for spatial planning and carbon management in Gansu Province and other regions that may have comparable challenges.

Experimental and numerical modelling of water waves in sewer networks during sewer/surface flow interaction using a coupled ODE‐SWE solver

AbstractFlooding in urban areas is expected to increase its magnitude and frequency in the future. Therefore, there is a strong need to better model sewer–surface flow interactions. Existing numerical methods are commonly based on simplified representations of sewer/surface mass exchange, and mainly validated in steady flow conditions. Current methodologies describing the propagation of transient conditions/waves through interaction nodes are simplified, rely on empirical coefficients and/or lack detailed validation. In this paper, an integrated numerical approach for modelling the propagation of water waves through interaction nodes (e.g., manholes) is presented. In this solution, the shallow water equations are used to simulate the free‐surface propagation inside the sewer network, and an ordinary differential equation is employed for modelling flow regimes through pipes and manholes. The model proposed is validated against the well‐known STAR‐CD modelling software for a number of test cases. Finally, further validation is performed against experimental data describing the evolution of water depth around a manhole in unsteady surcharging conditions.

Dissolved gas recovery from water using a sidestream hollow-fiber membrane module: First principles model synthesis and steady-state validation

This paper presents a first-principles model for the recovery of dissolved gases from liquids using a sidestream hollow-fiber membrane module. The model avoids the use of new empirical coefficients, thus providing a parametric understanding of the process behavior for future design and optimization of membrane modules. This type of first-principles model could be particularly useful when gas recovery is beneficial to biological or chemical reactions of interest, such as the acetogenesis reactions in two-stage anaerobic digesters. The steady-state behavior of the model was validated against both new experimental data for the recovery of H2, CH4 and H2–CH4 mixtures from pure water, as well as existing published data. The modeled gas recovery predictions agreed with experimental data to an absolute average error of 13%, and an average R2 value of 0.98. Parametric analysis of mixed-gas recovery suggests possible key transition points in the composition of the recovered gases. For example, at 40 °C, increasing trans-membrane pressure while keeping hydraulic residence time (HRT) under 0.5 s will result in an increase in the ratio of H2 to CH4 recovered. Otherwise, increasing trans-membrane pressure will instead decrease the ratio of H2 to CH4 recovered. The model has potential to be extended to transient analysis, but has yet to be validated with transient experimental data. This model was successfully implemented in both Python and MATLAB, and provides valuable insights for future net-energy optimization for anaerobic digestion systems with in-situ gas recovery.

Diurnal Variation Characteristics of Summer Precipitation over the Northern Slope of the Tianshan Mountains, Xinjiang, Northwest China: Basic Features and Responses to the Inhomogeneous Underlying Surface

The diurnal variation characteristics of precipitation in summer (June–August) during the period of 2015–2019 over the Northern Slope of the Tianshan Mountains (NSTM) was analyzed using hourly simulated data from Nanjing University’s real-time forecasting system (WRF_NJU) with 4 km resolution, Automatic Weather Station (AWS) data, and the ERA5-Land data through using methods such as the Rotated Empirical Orthogonal Function (REOF) and Coefficient of Variation (CV). The results show that the diurnal variation pattern of the precipitation over the NSTM simulated by WRF_NJU aligns closely with that of the observational AWS data, and it captured spatial distribution, peak values, and the times of precipitation reasonably well. The hourly precipitation amount (PA), precipitation frequency (PF), and precipitation intensity (PI) all show characteristics of being greater in the afternoon to nighttime than from early morning to noon, and the diurnal variations of precipitation in this region are significantly influenced by altitude. The PA, PF, and PI peak over the southern edge of the Junggar Basin (JB) below 1000 m occurred at around 2200 Local Solar Time (LST). In contrast, peak PA over the mountainous regions above 3000 m occurred at around 1500 LST. Further analysis with REOF and CV indicated that the difference in diurnal variations of precipitation between the mountainous regions and the JB is most pronounced likely due to the topographical influences. The peak PA over the mountainous regions mainly occurred at around 1500 LST, while that of the JB occurred at around 0100 LST. High CV regions for PI are predominantly found over the area near the central JB and the middle Tianshan mountains, whereas high CV regions for the PF are located in the central and northern parts of Urumqi and Changji. In addition, different land surface categories exhibit distinct patterns of diurnal precipitation variation, i.e., the forests, grasslands, and water bodies exhibit their peak PA in the period from early morning to noon, while the impervious surfaces, croplands, and barren lands exhibit their peak PA in the period from afternoon to nighttime.

Deformation evolves from shear to extensile in rocks due to energy optimization

Determining how fracture network development leads to macroscopic failure in heterogeneous materials may help estimate the timing of failure in rocks in the upper crust as well as in engineered structures. The proportion of extensile and shear deformation produced by fracture development indicates the appropriate failure criteria to apply, and thus is a key constraint in such an effort. Here, we measure the volume proportion of extensile and shear fractures using the orientation of the fractures that develop in triaxial compression experiments in which fractures are identified using dynamic in situ synchrotron X-ray imaging. The fracture orientations transition from shear to extensile approaching macroscopic, system-size failure. Numerical models suggest that this transition occurs because the fracture networks evolve in order to optimize the total mechanical efficiency of the system. Our results provide a physical interpretation of the empirical internal friction coefficient in rocks.

Unified multi‐objective optimization for regional power systems with unequal distribution of renewable energy generation and load

AbstractThe optimization for large‐scale power systems with unequal renewable energy distribution is an important and urgent task to collaborate operations of the participated sub‐grids. This article proposes a novel method by utilizing the unified multi‐objective optimization (MOO) to integrate diverse strategies to a comprehensive problem. For this aim, individual optimal model is first established to describe the demands of each sub‐grid. The overall objectives are unified in terms of economy costs. This unification integrates evaluate different optimized results without loss of generality. The global objective is the weighted sum of the individual objectives with empirical coefficient. Thus, the internal coupled restrictions and influences among sub‐grids can be solved simultaneously. Finally, by adjusting the corresponding weights according to the preferred requirement, the optimized solution can effectively allocate renewable energy throughout all sub‐grids. Consequently, both individual and global requirements can be met at utmost. The proposed unified MOO is tested on the configured systems based on multiple modified PJM 9‐bus grids. Satisfying the global optimum of the multi‐region joint system, the total system cost increases by 15.1%, the industrial zone cost increases by 21.4%, and the residential load shedding loss cost increases by 27.3%. Although each region has to sacrifice some of its benefits, the compromise operational behavior ensures that the total cost is optimal. Numerical results verify the effectiveness in achieving the promising global optimal solution, and the flexibility in meeting the requirements of different sub‐grids.

A concise analytical model for the ideal reverse osmosis desalination processes.

Permeate recovery is a key parameter that plays a central role in the performance assessment and optimization of reverse osmosis processes. It remains a great challenge for engineers in the field to determine the recovery conveniently and accurately from the basic parameters of a membrane system. A concise analytical model is presented here that, without the need for the empirical or fitting coefficients and tedious numerical calculation, links the recovery of a reverse osmosis process rigorously to three basic parameters: the feed water salt concentration, the characteristic of membrane process, and the driving pressure. A graphical solution method to the model is also introduced to find out the recovery effortlessly. The concise model and graphical method are demonstrated under various conditions as a powerful tool for the performance simulations and improvement of reverse osmosis processes. PRACTITIONER POINTS: A concise model is presented for permeate recovery in an ideal RO desalination system. The recovery of an RO system is analytically related to a few system parameters. A graphical solution method is introduced to find out the explicit recovery. The ideal RO model can be a powerful tool for simulation of RO processes.

Thermal performance study of buildings and their corresponding scale models with identical constructions and geometrical similarity

Small-scale physical model testing can be applied to calibrate a computational building energy model based on the acquired reliable thermal performance data. The calibration approach using a small-scale physical model is a rigorous and cost effective means in order to do an accurate full-scale building energy simulation. It is meaningful to reveal the correlation of the thermal performance between a full-scale building and its scale model, so that the data from a small-scale model testing can be scalable to predict the performance of a full-scale building. The purpose of the research is to investigate the correlations reflecting the comparative thermal performance of a full-scale building against its scale model with identical constructions and geometrical similarity. More than ninety thousand scenarios about the typical target building zones and their corresponding scale models were generated via the parametric energy modeling and simulation approach. Then, the typical thermal performance indicator of each building zone, i.e. the zone mean air temperature (ZMAT), was obtained. The result shows that the zone mean air temperature difference between the target building and its scale model is a time dependent variable with the diurnal cycle. Compared with a fixed scale model, the bigger building causes the larger variation of zone mean air temperature difference. Furthermore, it also indicates that the zone mean air temperature difference can be approximated by a logarithmic regression function as ALn(SF/d)+B, where A and B are empirical coefficients associated with climate, building form, material and construction, as well as window-to-wall ratio. In engineering practice, the outcomes of the research are applicable for thermal performance estimation and energy model calibration of full-scale buildings, especially for a planned building with the available material and construction samples, but without the determined or reliable thermal performance data for the building.

ПРОГНОЗИРОВАНИЕ СРОКА СЛУЖБЫ АНТИКОРРОЗИОННЫХ ПОКРЫТИЙ МЕТАЛЛИЧЕСКИХ КОНСТРУКЦИЙ ОБЪЕКТОВ ПЕРЕРАБОТКИ, ХРАНЕНИЯ И ТРАНСПОРТИРОВКИ УГЛЕВОДОРОДОВ

Leaks of liquid and gaseous hydrocarbons from pipelines and equipment of transportation, storage and processing facilities lead to fires and explosions. Often the cause of hydrocarbon leaks is corrosion of metal structures, leading to their depressurization. To increase the durability of metal structures, they are protected with anticorrosive coatings. The protective ability of the anticorrosive coating is determined by its continuity (defect). The prediction of the continuity (defectiveness) of the anticorrosive coating is carried out using empirical exponential or power expressions. The disadvantage of these expressions is a large number of hard-to-determine factors and empirical coefficients. An empirical expression is given to assess the defectiveness of the anticorrosive coating at the current time. An empirical expression is proposed for predicting the operational continuity (defectiveness) of an anticorrosive coating, taking into account the production (initial) defectiveness, the permissible service life and the aggressiveness of the environment. It is shown that the aggressiveness of the environment significantly affects the continuity (defectiveness) anticorrosive coating. The results of forecasting the continuity (defectiveness) of the anticorrosive coating are compared according to the currently used expressions and according to the proposed expression.
 The obtained results of forecasting the continuity (defectiveness) of the anticorrosive coating are close. The empirical expression proposed for predicting the continuity (defectiveness) of the anticorrosive coating is promising for practical application.

Modified Accuracy of RANS Modeling of Urban Pollutant Flow within Generic Building Clusters Using a High-Quality Full-Scale Dispersion Dataset

To improve the reliability of the computational fluid dynamics (CFD) models of wind-driven pollutant dispersion within urban settings, a re-calibration study is conducted to optimize the standard k−ε model. A modified optimization framework based on the genetic algorithm is adapted to alleviate the computational expenses and to further identify ranges for each empirical coefficient to achieve the most reliable and accurate predictions. A robust objective function is defined, incorporating both the flow parameters and pollutant concentration through several linear and logarithmic measures. The coefficients are trained using high-quality and full-scale tracer experiments in a mock urban arrangement simulating a building array. The proposed ranges are 0.14≤Cμ≤0.15, 1.30≤Cε1≤1.46, 1.68≤Cε2≤1.80, 1.12≤σε≤1.20, and 0.87≤σk≤1.00. A thorough evaluation of the predicted flow and concentration fields indicates the modified closure is effective. The fraction of predictions within the acceptable ranges from measurements has increased by 8% for pollutant concentration and 27% for turbulence kinetic energy. The generality of the calibrated model is further tested by modeling additional cases with different meteorological conditions, in which the calculated validation metrics attest to the noteworthy improvements in predictions.

Engineered cementitious composites design framework for pavement applications

Engineered cementitious composites (ECCs) have gained attention as a potential material alternative for extending the lifespan of pavements and overlays due to their exceptional mechanical strength and ductility. This study presents a novel thickness design framework that incorporates the elastic and plastic regimes of ECCs, along with a wide range of mechanical properties, to develop general thickness design equations for the fatigue failure mode of ECC pavements. The pavement thickness design framework proposed in this study integrates three components: (1) experimental models characterizing the beam flexural fatigue performance of ECC materials; (2) Finite Element (FE) analysis to quantify the stress response of ECC pavements under vehicular loading; and (3) empirical stress equivalency functions to combine the FE analysis results with the beam flexural fatigue models and predict the fatigue life of ECC pavements during the plastic regime. Using the proposed framework, two general thickness design equations predicting the service life of ECC pavements were developed, one for the elastic regime and one for the plastic regime of ECCs. The thickness design equations developed are in terms of ECC material properties and empirical coefficients, which can be determined through experimentation and modeling. The analysis of the results indicates that the proposed framework provides a more accurate representation of the service life of ECC pavements, particularly during the plastic deformation regime, compared to previous design frameworks discussed in the literature.

Role of land cover in Finland’s greenhouse gas emissions

We present regionally aggregated emissions of greenhouse gases (GHG) from five land cover categories in Finland: artificial surfaces, arable land, forest, waterbodies, and wetlands. Carbon (C) sequestration to managed forests and unmanaged wetlands was also assessed. Models FRES and ALas were applied for emissions (CO2, CH4, N2O) from artificial surfaces and agriculture, and PREBAS for forest growth and C balance. Empirical emission coefficients were used to estimate emissions from drained forested peatland (CH4, N2O), cropland (CO2), waterbodies (CH4, CO2), peat production sites and undrained mires (CH4, CO2, N2O). We calculated gross emissions of 147.2 ± 6.8 TgCO2eq yr−1 for 18 administrative units covering mainland Finland, using data representative of the period 2017–2025. Emissions from energy production, industrial processes, road traffic and other sources in artificial surfaces amounted to 45.7 ± 2.0 TgCO2eq yr−1. The loss of C in forest harvesting was the largest emission source in the LULUCF sector, in total 59.8 ± 3.3 TgCO2eq yr−1. Emissions from domestic livestock production, field cultivation and organic soils added up to 12.2 ± 3.5 TgCO2eq yr−1 from arable land. Rivers and lakes (13.4 ± 1.9 TgCO2eq yr−1) as well as undrained mires and peat production sites (14.7 ± 1.8 TgCO2eq yr−1) increased the total GHG fluxes. The C sequestration from the atmosphere was 93.2 ± 13.7 TgCO2eq yr−1. with the main sink in forest on mineral soil (79.9 ± 12.2 TgCO2eq yr−1). All sinks compensated 63% of total emissions and thus the net emissions were 53.9 ± 15.3 TgCO2eq yr−1, or a net GHG flux per capita of 9.8 MgCO2eq yr−1.

ARE REDUCED-SCALE EXPERIMENTS OF WAVE DAMPING BY VEGETATION SUITABLE FOR ENGINEERING WITH NATURE?

Wave damping by vegetation has been included in many numerical models for coastal engineering primarily through a parameterized expression for the wave height decay following Mendez and Losada (2004). CD is an empirical coefficient often derived from reduced-scale laboratory experiments in which alpha is measured directly. Multiple values of CD can be determined from a series of tests and CD is often given as a function of the Reynolds number, Re. These empirical relations for CD are subsequently used along with the vegetation and wave properties to estimate the wave damping rate in numerical models. Although CD has been shown to have a Reynolds-dependence, it is well known that Reynolds similitude cannot be held between model and prototype when Froude similitude is applied. This disparity raises a fundamental scaling issue to be explored in this paper: Are drag coefficients obtained by reduced-scale experiments of wave damping by vegetation suitable for engineering design?

Roughness Parameter of Shallow Water Bodies

The results of measurements of atmospheric turbulence characteristics were used to obtain parameterizations for calculating the dynamic roughness parameter and the roughness parameters for temperature and humidity for a shallow closed water body. At medium wind speeds, the results of calculations by Charnock formula are in agreement with observation data; in this case, the c parameter is three times as large as that in the case of an open ocean, and the passage from the viscous to wave mechanism occurs at high wind speeds, while the dynamic roughness parameter at the same wind speeds is greater. The roughness parameters for temperature and humidity at wind speed from 0.5 to 3 m/s are not equal. The empirical coefficients in the equations describing the ratio of the dynamic roughness to the roughness parameter for temperature (humidity) on Reynolds number are close to those obtained before for other closed water bodies, thus suggesting a common formation mechanism of transport processes in a viscous sublayer. The obtained parameterizations can be used in Earth system models and lake models for calculating turbulent flows over continental water bodies.

ASSESMENT OF WAVE OVERTOPPING ON REEF-FRONTED SHORES

Overtopping has been widely studied to design coastal structures, and it is also an important parameter for coastal management in order to evaluate the protection by natural coastal systems against inundation. Most formulations for open coasts have estimated overtopping using the wave runup (R2 percent), the beach slope and the truncated point, with empirical coefficients to account for further details (e.g. EurOtop, 2018). However, for beaches that are naturally protected by fringing reefs, the knowledge of overtopping is limited, and reliable analytical formulations have not been developed. The aim of this research is to evaluate the previous overtopping model and scaling laws and suggest one model applicable to reef-fronted shores.

Transient Thermal Analysis of a Double Duct Solar Roof Chimney Coupled With a Scaled Room

Abstract This research presents a detailed transient experimental and computational study of heat transfer and airflow in a scaled room linked with a double-duct vertical roof solar chimney (SC). The analysis was made in the coupled system, varying the heat flux supplied to the roof SC absorber during the day. Experimental temperature profiles were obtained at six different depths and heights, the empirical heat transfer coefficient was computed for the SC absorber, and the variation of air changes per hour was determined. A good agreement between experimental and numerical temperature profiles and average Nusselt number (Nut) is shown in the latter of average difference of 3.41%. The validated computational model was used to analyze the effect of the transient heating of the SC on temperature fields and flow patterns in the thermal system. Almost symmetrical temperature and y-velocity profiles are formed in the ducts at different hours of the day, with thermal boundary layers of about 4 mm. Correlations of the Nusselt number and air changes per hour (ACH) are provided as a function of the modified Rayleigh number.