Suitable Calculation Method Research Articles

A study of particle motion in Kwerk-type twisted blades: Effect of configuration on particle mixing performance by CFD–DEM

Static mixers could promote the particle mixing in industries. Experimental and numerical investigations of particle mixing and flow characteristics in the riser with static mixers are carried out. The instantaneous microscopic characteristics and energy loss in Kwerk-type static mixer (K-KSM) are evaluated by Computational Fluid Dynamics coupled with Discrete Element Method (CFD–DEM). A more suitable calculation method is proposed, which utilizes particle coordinates and the coordination number of central particles to calculate the instantaneous mixing degree of particles (PK). The PK, Residence Time Distribution (RTD) and collision correlation are analyzed at different superficial gas velocities (Ug) and mass flow rates (Ms). The results show that the performance of K-KSM is superior to that of KSM under current conditions. Back mixing and aggregation phenomena are eliminated at Ug > 5 m/s and Ms < 1.73 g/s, and the recommended regimes are Ug ≥ 6.0 m/s and Ms < 1.5 g/s.

International Council for Standardization in Haematology Field Study Evaluating Optimal Interpretation Methods for Activated Partial Thromboplastin Time and Prothrombin Time Mixing Studies.

The prothrombin time (PT) and activated partial thromboplastin time (APTT) are screening tests used to detect congenital or acquired bleeding disorders. An unexpected PT and/or APTT prolongation is often evaluated using a mixing test with normal plasma. Failure to correct ("noncorrection") prolongation upon mixing is attributed to an inhibitor, whereas "correction" points to factor deficiency(ies). To define an optimal method for determining correction or noncorrection of plasma mixing tests through an international, multisite study that used multiple PT and APTT reagents and well-characterized plasma samples. Each testing site was provided 22 abnormal and 25 normal donor plasma samples, and mixing studies were performed using local PT and APTT reagents. Mixing study results were evaluated using 11 different calculation methods to assess the optimal method based on the expected interpretation for factor deficiencies (correction) and noncorrection (inhibitor effect). Misprediction, which represents the failure of a mixing study interpretation method, was assessed. Percentage correction was the most suitable calculation method for interpreting PT mixing test results for nearly all reagents evaluated. Incubated PT mixing tests should not be performed. For APTT mixing tests, percentage correction should be performed, and if the result indicates a factor deficiency, this should be confirmed with the subtraction III calculation where the normal pooled plasma result (run concurrently) is subtracted from the mixing test result with correction indicated by a result of 0 or less. In general, other calculation methods evaluated that performed well in the identification of factor deficiency tended to have high misprediction rates for inhibitors and vice versa. No single method of mixing test result calculation was consistently successful in accurately distinguishing factor deficiencies from inhibitors, with between-reagent and between-site variability also identified.

Recarbonation matters—CO2 absorption of AAC during its use phase

AbstractRebounding of CO2 during service life and recycling in building materials reduces the CO2 content of the atmosphere. The CO2 was formerly released from limestone through deacidification during the production of cement and quicklime. Binder‐bound building materials later reabsorb this CO2 again. This process is called recarbonation. In contrast to concrete, detailed knowledge about the CO2 cycles of autoclaved aerated concrete (AAC) is missing. Standards concerning adequate sampling and measurement methods as well as suitable calculation methods are currently under development.According to the valid EN 15804:2012+A2:2019, life cycle assessments and environmental product declarations (EPDs) concern the entire product life cycle and thus also the CO2 reabsorption by building materials. For AAC, this amount can be calculated from the raw material input. The reduction bases on the active CaO contained in the AAC, is absolute and related to the binder mass used. Thus, it can be applied comprehensively and without the influence of the used database system of the background data in EPDs.Unfortunately, the amount of originally active CaO cannot be measured directly in AAC samples. As a first approximation, it was obvious to assume that all chemically determinable CaO in AAC was formerly active. However, this method underestimates the degree of recarbonation because the raw materials also contain non‐reactive CaO, for example, in the form of calcium silicates. Nevertheless, all diagrams concerning recarbonation of AAC are based on this assumption and the values are too low.In the presentation, we will introduce a new method to determine the degree of recarbonation of AAC—forced carbonation. Forced carbonation is carried out under defined temperature, humidity, and CO2 conditions in a climate chamber. The measurement is bases on the detection of CO2 in the sample and considers the proportion of non‐reactive CaO and thus leads to realistic degrees of recarbonation.

The simple network-based measuring system for improving the evaporation estimation

Abstract This paper presents a novel method for measuring the data for evaporation estimation as the key ingredient for the final decision of the reclamation form in the area of the Most Basin. The area has been intensively mined for many decades, resulting in significant landscape devastation, loss of natural habitats, and negative environmental impact. Currently, it is assumed that by 2050, three large-scale reclamation projects will be implemented in the area and it is necessary to decide which form of reclamation to choose. Whether to build lakes according to the currently valid rehabilitation and reclamation plan or to leave the area of the quarries in succession with the support of spontaneous inflow of water up to a naturally sustainable water level. Whether the first or second option is approved, or a combination of both, the prediction of evaporation from the free water surface will always be of great importance. To deal with this goal, the available meteorological data must be combined with a suitable calculation method. In our work, we suggest utilizing a measuring network of meteorological devices that describe the character of the weather in a given area of interest in a long-term time series. Together with the state-of-the-art calibration of models for calculating evaporation, the measurement network helps to provide more accurate evaporation data for a given area. Based on the analysis of research results, it will be possible to choose a specific right decision and thus contribute to the long-term sustainability of these reclamations.

The Comparation of Water Saturation Approaches to Reveal a Low Resistivity Reservoir Potential Case in Gumai Formation, South Sumatra Basin

The LRLC reservoir zone has been identified in SN-3 well, at the DAP-1 interval on Gumai Formation. This interval has a low resistivity value from 3-5 ohm.m and the drill stem test (DST) results show oil with gas without water. This study is objected to identify the causes of LRLC reservoir in gumai formation and finding a suitable sw calculation method. Some data such as well logs, reports, cores, and XRD are used to calculate petrophysical parameters such as Vsh, Phie, and Sw, and would be validated by DST data. Water saturation (Sw) calculations from Archie and the CEC method (Waxman Smits, Dual Water, Juhasz) were performed and the results were compared. The results showed that the main cause of the DAP-1 interval LRLC zone was the presence of clay minerals consisting of mixed layers (Illite/smectite). These clay minerals will be associated with high cation exchange capacity (CEC) values, with the value 70 (meq/100g), which can increase conductivity and reduce resistivity values. Based on lumping the more optimistic results of sw calculation from Waxman Smits Sw method (Sw based on CEC method). The DST data on the SN-3 well does not have water test data, so the calculation of the Sw value that is close to the Swirr value is considered the most suitable Sw for the low resistivity reservoir conditions of the Gumai Formation in the study area. The best practice for low resistivity reservoir for suitable petrophysical calculation is necessary to pay attention to the rock lithology conditions, the presence of mineral clay, and determining suitable Sw appropriate to the reservoir conditions

Research on the calculation method of penetration resistance of bucket foundation for offshore wind turbines

The cost of foundations for offshore wind turbines constitutes approximately 35% of the total cost of an offshore wind farm. The bucket foundations show significant potential due to their superior transportation and installation efficiencies compared to pile foundations, leading to potential cost savings for the foundation of up to 30%. For a bucket foundation to be installed successfully, the penetration resistance must be predicted. However, there is currently a lack of clarity on how to select a suitable calculation method for penetration resistance based on known geological parameters to guide construction. In order to evaluate the current methods of calculation for bucket foundation penetration resistance, this study combines theoretical calculation methods with two sets of practical measurement data from the field. The calculation methods of penetration resistance for bucket foundation are first reviewed and categorized. The applicability range of each method and the parameters needed for calculation are given. Next, according to the measured data in the process of penetration of bucket foundation on site, the evolution of compartment pressure, tilt angle, resistance and required suction in the process of penetration are analyzed. Finally, the reviewed methods are compared to the results of two practical projects in order to analyze the differences between them and make recommendations for the calculation technique. The findings can be used as a guide for calculating the bucket foundation's penetration resistance in complex geological conditions.

Comparative Analysis of Tunnel Plastic Zone Calculation and Engineering Measurement Based on Various Methods

The characteristics of plastic zone are a critical basis for the control and stability analysis of the surrounding rock of roadways. This paper aims to investigate the rationality and applicability of the numerical methods for the plastic zone analysis of deep jointed rock roadways. Based on the detailed investigation and experiments, The plastic zone distribution of roadway surrounding rock under different GSI values and different buried depths was analyzed by analytical methods, parameter reduction, and equivalent rock mass technology, and then the acoustic wave measurement method was used to carry out the field measurement and was compared with the simulation results. The results show that when GSI is large, the difference between the results is not obvious. When GSI is small, the results obtained by the parameter reduction method and the analytical method show a more drastic increase and the discreteness increases. The results obtained by the equivalent rock mass technique are generally close to the measured values, and the growth rate is more uniform. According to the convenience of the calculation parameters and the accuracy of the calculation, the suitable calculation methods for different working conditions were suggested.

(Retracted) Mural digital image restoration technology and stitching evaluation model based on machine learning

Mural painting refers to art on the wall, which has high aesthetic value. However, due to its vulnerability to damage, digital image restoration and stitching techniques are now used to permanently preserve mural images. The purpose of our study is to select a more suitable specific calculation method by studying machine learning (ML) methods and conduct in-depth research on mural digital image restoration technology and stitching evaluation, so that it can better serve the restoration and splicing of the current mural digital images. Based on the experiments, it can be seen that the respondents in hall A had a high degree of recognition for digital image restoration and stitching technology. There were 176 respondents, and only 29 people believed that digital image restoration was not important; respondents in hall C did not agree with the digital image restoration technology as much as hall A, only 132 people thought it was important, and 64 people thought it was not important. It can be seen that the model establishment of mural digital image restoration technology and splicing evaluation is deeply affected by the knowledge level of the evaluator. The experimental results of our study showed that the research process of mural digital image restoration technology and stitching evaluation based on ML method was more effective than other methods of analyzing experimental data.

Forced carbonation – A new method to determine the degree of recarbonation of calcium silicate units

AbstractRebound effects in building materials reduce the CO2 content of the atmosphere. This reabsorption of CO2 during service life and recycling is called recarbonation. In contrast to concrete, detailed knowledge about the CO2 cycles of autoclaved aerated concrete and calcium silicate units is missing. Moreover, standards concerning adequate sampling methods as well as suitable calculation methods do not exist yet.Autoclaved aerated concrete is a highly porous material and recarbonizes evenly. Hence, samples for examination can be drilled out. In contrast, calcium silicate displays lower porosity and decreased CO2 permeability. Therefore, its recarbonation starts on the surface and penetrates inwards. The units are inhomogeneously recarbonized. Consequently, bulk samples – not drill samples – must be taken.In addition, calcium silicate contains considerable amounts of CaO bound in silicates. For this reason, the degree of recarbonation must not be calculated on the basis of the total CaO and CO2 content. The newly developed calculations are based on the maximum CO2 uptake determined using forced carbonation. It is carried out under defined temperature, humidity and CO2 conditions in a climate chamber. Thanks to this method, the degree of recarbonation of calcium silicate can be determined more precisely.

Density peaks clustering based on local fair density and fuzzy k-nearest neighbors membership allocation strategy

The density peaks clustering algorithm (DPC) has been widely concerned since it was proposed in 2014. There is no need to specify in advance and only one parameter required. However, some disadvantages are still witnessed in DPC: (1) Requiring repeated experiments for choosing a suitable calculation method of the local density due to the variations in the scale of the dataset, which will lead to additional time cost. (2) Difficulty in finding an optimal cutoff distance threshold, since different parameters not only impact the selection of cluster centers but also directly affect the quality of clusters. (3) Poor fault tolerance of the allocation strategy, especially in manifold datasets or datasets with uneven density distribution. Targetting solutions to these problems, a density peaks clustering based on local fair density and fuzzy k-nearest neighbors membership allocation strategy (LF-DPC) is proposed in this paper. First, to obtain a more balanced local density, two classic local density calculation methods are combined in the algorithm to calculate the local fair density through the optimization function with the smallest local density difference. Second, a robust two stage remaining points allocation strategy is designed. In the first stage, k-nearest neighbors are used to quickly and accurately allocate points from the cluster center. In the second stage, to further improve the accuracy of allocation, a fuzzy k-nearest neighbors membership method is designed to allocate the remaining points. Finally, the LF-DPC algorithm has been experimented based on several synthetic and real-world datasets. The results prove that the proposed algorithm has obvious advantages compared with the other five ones.

Review of Numerical Simulation Research on Submersible Mixer for Sewage

Submersible mixer is the core machinery of sewage treatment, which has a profound effect on the efficiency and performance of the submersible mixing system of sewage treatment. This paper summarizes the scientific research results of submersible mixer in recent years from four aspects: structure and energy characteristics of submersible mixer, numerical simulation calculation method, flow field characteristics, and factors affecting the flow field characteristics. The existing published literature indicates that the structure of submersible mixer for sewage is complicated and the parameters of energy characteristics are special. Few experimental studies are conducted, and mostly numerical calculations are based on clear water as the medium. The mixture model based on the Euler–Euler method is the multiphase flow model currently applied in the field of submersible mixer research. Many factors affect the mixing effect of a submersible mixer, such as installation factors (the location and angle of installation) and impeller design parameters (blade gap, hub-tip ratio, blade angle, etc.), all having a significant impact on the mixing performance. Meanwhile, the development and trends of submersible mixer technology are prospected, and the future directions of further research are proposed: establishing a more suitable numerical calculation method for submersible mixer based on the Euler–Lagrange model; constructing the calculation model with real fluid—solid-liquid two-phase flow as the medium; exploring the influence of various parameters on flow field characteristics of mixing fluid; getting the mixing mechanism of submersible mixer; promoting the development of submersible mixer; and realizing the efficient and stable operation of submerged mixing system.

Settlement Characteristics of Split Grouting Pile Composite Foundation in Loess Areas

Loess foundations often affect the stability of superstructures due to their insufficient bearing capacities; thus, reinforcement measures are crucial for mitigating the uneven settlement of foundations. This study aims to investigate the settlement characteristics of composite foundations for loess foundations reinforced by splitting grouting piles. First, split grouting tests were carried out on loess foundations. After the test piles reached the design strength, static load tests and geotechnical tests were carried out to obtain the Q‐s curves of the test piles. The pile‐forming mechanism was analyzed via excavations at an on‐site test pile. Furthermore, the traditional settlement calculation method of composite foundations was used to calculate the settlement of split grouting pile composite foundations, and the results were compared with field test results to explore a suitable settlement calculation method of split grouting pile composite foundations. Finally, the numerical model of split grouting pile composite foundations was established according to the pile forming mechanism, and the settlement deformation characteristics of single pile and pile group composite foundations were analyzed. The relative errors of the composite modulus method and the stress correction method for calculating the settlement of the composite foundations were 6.4% and 32.8%, respectively, and the composite modulus method was closer to the test values. The calculated curves of the numerical model were in good agreement with the measured curves and relevant literature research results, demonstrating the rationality of the modeling method; the findings of this study provide theoretical guidance for designing loess foundation splitting grouting reinforcement and for predicting settlement during later construction periods.

상가권리금 결정요인에 관한 연구 - 서울시 상가 통상임대료를 중심으로 -

This study aims to empirically present variables that influence the determinants of Retail’s Goodwill in major commercial districts in Seoul. The data used in this study were constructed based on 2,433 data from the "2020 Seoul-type Ordinary Rental Fee Survey" for 7,500 stores selected in consideration of the core streets of major commercial districts in 2020. Unlike the previous year, in this study, the deposit and monthly rent items were replaced based on Ordinary Rental Fee, and data were constructed by converting all expenses into the amount per unit area. The summary of the results of this study is as follows. In 2020, the average premium for major shopping malls in Seoul is 1.2138 million won/㎡, and the average rent is 60.8 thousand won/㎡. According to the analysis results, commercial rights had the highest positive (+) correlation with ordinary rent at +0.418, and the highest negative (-) correlation with the exclusive area at -0.175. In other words, the higher the normal rent per square meter, the higher the commercial right, and the higher the exclusive area, the lower the commercial right. The average monthly sales, facility investment costs, and presence or absence of parking lots had a major positive (+) correlation with commercial rights, and whether or not there was an independent street store from a subway station had a major negative (-) correlation. This study proves that the Ordinary Rental Fee survey of Seoul is the biggest factor in determining the determinants of commercial property rights and proves that it is a suitable calculation method for the Ordinary Rental Fee. It will help you figure out the amount.

Методы определения приоритета входных параметров функционально-математических библиотек с закрытым исходным кодом

This work mainly aimed to identify the most suitable calculation approaches and methods for the effect of inputs upon the outputs of a functionally-mathematical library with inaccessible source code, and further use these methods and approaches to develop an input ranking tool. These methods and approaches were studied using a generalized regressive model representing an arbitrary functionally-mathematical library (an executable module). The paper studied two approaches to the determination of input effects upon the outputs: 1) correlation analysis; 2) neural network method. The first method is analytical calculation (couple by couple) of Pierson correlation coefficients for all input and output parameters. As an alternative, the study also investigated rank-based Spierman and Kendall correlations. The second approach basically meant neural network learning with required accuracy using the variation set of executable module inputs and their respective outputs with subsequent calculation of contribution from each parameter to the overall result for the neural network after learning. These approaches have also been compared in terms of several major criteria, i.e. application peculiarities, speed and output quality. The analysis has shown that neural-network learning method, despite its certain drawbacks, is more suitable for the task of this study. The paper also outlined possible ways for further improvement of this method and complexity increase of the suggested functionally-mathematical library model.

Comment on Hamayun et al. Evaluation of Two-Column Air Separation Processes Based on Exergy Analysis. Energies 2020, 13, 6361

Oxygen production from air belongs to energy-intense processes and, as a result, possibilities for its decrease are a frequent topic of optimization studies, often performed with simulation software such as Aspen Plus or Aspen HYSYS. To obtain veritable results and sound solutions, a suitable calculation method hand in hand with justified assumptions and simplifications should form the base of any such studies. Thus, an analysis of the study by Hamayun et al., Energies 2020, 13, 6361, has been performed, and several weak spots of the study, including oversimplified assumptions, improper selection of a thermodynamic package for simulation and omission of certain technological aspects relevant for energy consumption optimization studies, were identified. For each of the weak spots, a recommendation based on good praxis and relevant scientific literature is provided, and general recommendations are formulated with the hope that this comment will aid all researchers utilizing Aspen Plus and Aspen HYSYS software in their work.

Optimal Design and Application of AGC Performance Index Measurement Standards for Generating Units Adapted To the China Southern Regional Frequency Regulation Auxiliary Service Market

With the advancement of the construction of the China southern regional frequency regulation auxiliary service market, the calculation method of the AGC performance index of the generator set needs to be further optimized. To this end, an optimization scheme for calculating the AGC performance index of generator sets that is suitable for the China southern regional frequency regulation auxiliary service market is proposed. First, the demand for AGC unit participation in the frequency regulation market is analyzed, and a model for AGC unit participation in the frequency regulation market is established. Through theoretical analysis and data comparison, it is shown that the traditional calculation method of AGC frequency modulation performance index is not suitable for the calculation of AGC performance of FM market units. Aiming at the key content of the frequency modulation market for the AGC performance requirements of the unit, a suitable calculation method is proposed. Finally, the actual case that illustrates the applicability of the index calculation method in this paper is analyzed.

Influence of local differences in microstructure and hardness on the fatigue behaviour of a slewing bearing steel

For a more accurate prediction of the service life of slewing bearings under oscillating mode mechanical customized fatigue test strategies and suitable calculation methods have to be developed. In this study large-diameter slewing bearings of onshore wind turbines made from induction hardened and tempered steel 42CrMo4 are investigated. Test samples were cut directly out of the bearing ring (core condition). The orientation of the test cross-section was chosen to corresponding with the presumed most critical orientation of non-metallic inclusions. After sampling three heat treatments were carried out to mimic the different heat treatment conditions of the bearing (raceway, transition region, core). Results of static tests (fracture toughness, tensile strength) and cyclic testing (crack propagation, S-N-curve) were obtained for the three different heat-treated sample batches. The results where correlated to hardness, cleanliness and local residual stresses to develop a deep understanding of crack initiation and crack propagation mechanisms and making a first step towards a more accurate prediction of fatigue life. In order to be able to transfer the analytic results to the real parts, a simulation model will be developed later on.

ВИЗНАЧЕННЯ ВПЛИВУ ВИТРАТ НА РЕКЛАМУ ЛІКАРСЬКИХ ЗАСОБІВ НА ЇХ ПРОДАЖІ ЗА ДОПОМОГОЮ ЕКОНОМІКО-МАТЕМАТИЧНОГО МОДЕЛЮВАННЯ

During of writing this article, we analyze the models of economic dynamics that have a relationship between advertising and costs. It was found that advertising in these models did not have the character that it has in practice, namely it did not have a cumulative effect for subsequent periods. A model of economic dynamics was formulated during the research, this model include the cumulative effect of advertising messages, if advertising will affect sales not in pointly, but it will continue to influence in subsequent periods. Also, the effect of resales is integrated into the model if the drug has a small volume of release, has a short shelf life, or is often used for prevention viruses. To develop the model, a time-based modeling approach was used. It has been suggested that although advertising is cumulative, over time the impact of advertising diminishes until it disappears altogether. It is assumed that due to the establishment of production restrictions of the firm, the impact of previous sales weakens. When formulating the model, it is believed that with a positive experience of interaction with the product, in our case with drugs, buyers can repeat purchases and advise the tool to others. A suitable numerical calculation method was found to solve the model. The method of modified local variations was used for the calculation, which is not difficult to reproduce in practice even without significant mathematical training. A correlation analysis of sales advertising was performed using Pearson's correlation coefficients and autocorrelation and it was found that the relationship between them becomes weaker as the lag increases. The revenue function is presented in nonlinear form. In the course of calculations, it was found that the revenue is ascending, which confirms the positive impact of advertising on sales. The study was conducted with different sampling steps and with each step the accuracy increased, but at the same time the calculation time. This study will be useful both to marketing agencies that shape advertising budgets of companies and to pharmaceutical companies themselves that want to make investment in advertising more effective.

Premium calculation on health insurance implementing deductible

Implementation of deductibles on insurance contracts is one of many ways to solve the adverse selection and moral hazard problems that often arise in health insurance. Deductibles will make the amount of expected loss for insurance companies lower. However, the deductible will also affect the amount of net premium. The higher the deductible, the lower the net premium that insurance company will get. If the claims amount are very large, then the insurance company would not be able to pay the claims because the amount of net premium that have been earned is small. Thus, the net premium principle is less suitable to use when the insurance companies. Then, they must find more suitable premium calculation method and in this paper, Proportional Hazard (PH) transform principle proposed by Wang being analyzed as an alternative premium when the insurer applies deductibles. The amount of PH transform premium will be higher than net premium and it has more slightly decrease when deductibles are applied compared to the amount of net premium.

Analysis of the Calculation Method for the Thermal Transmittance of Double Windows Considering the Thermal Properties of the Air Cavity

The calculation method for the thermal transmittance (U-value) of double windows as specified by the Korean government (ISO 15099) is often inappropriate. To develop a more suitable calculation method, the thermal properties of the air cavity between the internal and external windows should be considered. Herein, seven cases of double windows were set up. The air cavities were designed in accordance with international standards and computational fluid dynamics (CFD) and used for the calculation of the U-values of the double windows according to ISO 15099 and 10077. All the calculated U-values were compared with experimentally obtained values. In accordance with the ISO 10077-1 method, the thermal resistance of the air cavity calculated using CFD could produce double window U-values that are similar to the experimentally obtained values. In most cases, the difference between the theoretical and experimental U-values was 5% and less than 0.14 W·m−2·K−1, implying that the U-values calculated using CFD and the ISO 10077-1 method are approximately equal to the experimentally obtained U-values. Korean regulations do not include ISO 10077-1 for double-window assessment. However, these criteria can provide a solution in improving the accuracy of the calculation of the overall thermal transmittance of double windows.