Investigation of the process of fluoride ions adsorption by natural sorbents

2021 ◽  
Vol 6 (3) ◽  
pp. 181-187
Author(s):  
Vira Sabadash ◽  
◽  
Oksana Liuta ◽  
Jaroslaw Gumnitsky ◽  
◽  
...  
Keyword(s):  
Coefficient Of Determination ◽  
Preliminary Treatment ◽  
Statistical Parameters ◽  
Fluoride Ions ◽  
Aluminium Fluoride ◽  
Mechanism Of Interaction ◽  
Defluoridation Of Water ◽  
Adsorption Treatment ◽  
Degree Of Purification

A detailed analysis of literature sources on the content of fluorides in the environment, methods of conditioning and defluoridation of water was held. The mechanism of interaction of fluorides with zeolite in the process of adsorption treatment of wastewaters and domestic waters was clarified. It was first established that in the process of adsorption there is the formation of magnesium fluoride compounds due to the binding of cations extracted from the zeolite by the mechanism of ion exchange. The mechanism of chemisorption of fluoride ions by the formation of insoluble CaF2 was also proved. According to the results of experimental research, a technological scheme has been developed, which provides the preliminary treatment of fluoride ions in the form of complexes with aluminium. In order to prevent the permeation of aluminium fluoride into the treated water, a stage of adsorption water purification was proposed. Calculations of the amount of reagent necessary to ensure the required degree of purification of water from fluoride ions were done. The statistical parameters of the process and the significance of the obtained results were calculated. The coefficient of determination of experimental data was 0.87… 0.99, the standard deviation was 0.017… 0.026.

scholarly journals Validation of the procedure: Quantification of the degradation index of Photovoltaic Grid Connection Systems

2021 ◽  
Vol 2 (5) ◽  
pp. 8-13
Author(s):  
Proenza Y. Roger ◽  
Camejo C. José Emilio ◽  
Ramos H. Rubén
Keyword(s):  
Mean Absolute Error ◽  
Absolute Error ◽  
Coefficient Of Determination ◽  
Mean Square ◽  
Degradation Index ◽  
Statistical Parameters ◽  
Grid Connection ◽  
The Mean

The results obtained from the validation of the procedure ‟Quantification of the degradation index of Photovoltaic Grid Connection Systems” are presented, using statistical parameters, which corroborate its accuracy, achieving a coefficient of determination of 0.9896, a percentage of the root of the mean square of the error RMSPE = 1.498% and a percentage of the mean absolute error MAPE = 1.15%, evidencing the precision of the procedure.

scholarly journals Modeling Population Spatial-Temporal Distribution Using Taxis Origin and Destination Data

2021 ◽  
Vol 13 (7) ◽  
pp. 3727
Author(s):  
Fatema Rahimi ◽  
Abolghasem Sadeghi-Niaraki ◽  
Mostafa Ghodousi ◽  
Soo-Mi Choi
Keyword(s):  
Regression Analysis ◽  
Mean Squared Error ◽  
Population Distribution ◽  
Temporal Distribution ◽  
Coefficient Of Determination ◽  
Temporal Modeling ◽  
Location Data ◽  
Time Period ◽  
Proposed Model

During dangerous circumstances, knowledge about population distribution is essential for urban infrastructure architecture, policy-making, and urban planning with the best Spatial-temporal resolution. The spatial-temporal modeling of the population distribution of the case study was investigated in the present study. In this regard, the number of generated trips and absorbed trips using the taxis pick-up and drop-off location data was calculated first, and the census population was then allocated to each neighborhood. Finally, the Spatial-temporal distribution of the population was calculated using the developed model. In order to evaluate the model, a regression analysis between the census population and the predicted population for the time period between 21:00 to 23:00 was used. Based on the calculation of the number of generated and the absorbed trips, it showed a different spatial distribution for different hours in one day. The spatial pattern of the population distribution during the day was different from the population distribution during the night. The coefficient of determination of the regression analysis for the model (R2) was 0.9998, and the mean squared error was 10.78. The regression analysis showed that the model works well for the nighttime population at the neighborhood level, so the proposed model will be suitable for the day time population.

scholarly journals A Multimethod Analysis for Average Annual Precipitation Mapping in the Khorasan Razavi Province (Northeastern Iran)

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 592
Author(s):  
Mehdi Aalijahan ◽  
Azra Khosravichenar
Keyword(s):  
Regional Planning ◽  
Interpolation Method ◽  
Absolute Error ◽  
Rain Gauge ◽  
Annual Precipitation ◽  
Coefficient Of Determination ◽  
Distance Weighting ◽  
Average Annual Precipitation ◽  
Inverse Distance

The spatial distribution of precipitation is one of the most important climatic variables used in geographic and environmental studies. However, when there is a lack of full coverage of meteorological stations, precipitation estimations are necessary to interpolate precipitation for larger areas. The purpose of this research was to find the best interpolation method for precipitation mapping in the partly densely populated Khorasan Razavi province of northeastern Iran. To achieve this, we compared five methods by applying average precipitation data from 97 rain gauge stations in that province for a period of 20 years (1994–2014): Inverse Distance Weighting, Radial Basis Functions (Completely Regularized Spline, Spline with Tension, Multiquadric, Inverse Multiquadric, Thin Plate Spline), Kriging (Simple, Ordinary, Universal), Co-Kriging (Simple, Ordinary, Universal) with an auxiliary elevation parameter, and non-linear Regression. Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and the Coefficient of Determination (R2) were used to determine the best-performing method of precipitation interpolation. Our study shows that Ordinary Co-Kriging with an auxiliary elevation parameter was the best method for determining the distribution of annual precipitation for this region, showing the highest coefficient of determination of 0.46% between estimated and observed values. Therefore, the application of this method of precipitation mapping would form a mandatory base for regional planning and policy making in the arid to semi-arid Khorasan Razavi province during the future.

scholarly journals A NON-DESTRUCTIVE METHOD FOR ESTIMATING LEAF AREA OF Ceiba glaziovii (Kuntze) K. Schum.

FLORESTA ◽  
2019 ◽  
Vol 50 (1) ◽  
pp. 1063
Author(s):  
João Everthon da Silva Ribeiro ◽  
Francisco Romário Andrade Figueiredo ◽  
Ester Dos Santos Coêlho ◽  
Walter Esfrain Pereira ◽  
Manoel Bandeira de Albuquerque
Keyword(s):  
Leaf Area ◽  
Regression Models ◽  
Information Criterion ◽  
Coefficient Of Determination ◽  
Linear Measurements ◽  
Maximum Width ◽  
Bias Index ◽  
Different Shapes ◽  
Non Destructive

The determination of leaf area is of fundamental importance in studies involving ecological and ecophysiological aspects of forest species. The objective of this research was to adjust an equation to determine the leaf area of Ceiba glaziovii as a function of linear measurements of leaves. Six hundred healthy leaf limbs were collected in different matrices, with different shapes and sizes, in the Mata do Pau-Ferro State Park, Areia, Paraíba state, Northeast Brazil. The maximum length (L), maximum width (W), product between length and width (L.W), and leaf area of the leaf limbs were calculated. The regression models used to construct equations were: linear, linear without intercept, quadratic, cubic, power and exponential. The criteria for choosing the best equation were based on the coefficient of determination (R²), Akaike information criterion (AIC), root mean square error (RMSE), Willmott concordance index (d) and BIAS index. All the proposed equations satisfactorily estimate the leaf area of C. glaziovii, due to their high determination coefficients (R² ≥ 0.851). The linear model without intercept, using the product between length and width (L.W), presented the best criteria to estimate the leaf area of the species, using the equation 0.4549*LW.

scholarly journals The Effect of Financial Leverage, Operating Leverage and Current Ratio on Profitability at PT. Manunggal Persada Jakarta

2019 ◽  
Vol 3 (2) ◽  
pp. 135
Author(s):  
Waluyo Jati
Keyword(s):  
Hypothesis Testing ◽  
Regression Coefficient ◽  
Sampling Technique ◽  
Coefficient Of Determination ◽  
Analysis Tool ◽  
Financial Leverage ◽  
Current Ratio ◽  
Independent Variable ◽  
Operating Leverage

Funds can be obtained from company owners or from outside parties. The purpose of this study was to determine the effect of financial leverage, operating leverage and current ratio on profitability at PT. Manunggal Persada Jakarta. The method used in this research is descriptive with an associative approach, the sampling technique used is proportional random sampling using the census or saturated sampling method with a sample of 7 years of financial statements. The analysis tool uses classical assumption testing, regression testing, determination coefficient testing and hypothesis testing. The results of the study concluded that the regression coefficient value of Financial leverage of 0.005 was positive with a contribution of 19.3%. Hypothesis testing obtained a significance value of 0.324> 0.05. Regression coefficient value of Operating leverage of 0.001 is positive with a contribution of 16.5%. Hypothesis testing obtained a significance value of 0.368> 0.05. Current coefficient regression value of 0.158 is positive with a contribution of 31.9%. Hypothesis testing obtained a significance value of 0.187> 0.05. Obtained a regression equation Y = 0.110 + 0.009X1 + 0.001X2 + 0.177X3, the regression coefficient value of each positive independent variable with a correlation of 0.927 and a coefficient of determination of 85.8% while the remaining 14.2% is influenced by other factors. Hypothesis testing obtained by calculating Fcount> Ftable or (6.064> 4.120). Thus simultaneously there is a positive and significant effect between financial leverage, operating leverage and current ratio to rentability.

scholarly journals The Influence Of International Brand Image Toward Guest's Decision To Stay At The Four Star Hotel In Lampung

2021 ◽  
Vol 4 (1) ◽  
pp. 38
Author(s):  
Dina Mayasari Soewoyo ◽  
Handono W Widodo
Keyword(s):  
Brand Image ◽  
Linear Regression Analysis ◽  
Software Tool ◽  
Primary Data ◽  
Coefficient Of Determination ◽  
Analysis Technique ◽  
Independent Variable ◽  
Decision To Stay ◽  
Decisions To Stay

<div class="WordSection1"><p>This survey research using the quantitative method was carried out during the Covid-19 pandemic, from May to August 2020 at the 4-star hotel in Lampung Province, Indonesia. The purpose of this study was to determine the influence of the independent variable, namely the image of the international hotel brand toward the dependent variable of guests' decisions to stay at the hotel. Primary data of the study were obtained from the results of distributing questionnaires which were carried out directly to 60 guests who were staying, as research samples and measured using a Likert scale of 1 - 4. Apart from distributing questionnaires, research data collection was also gained through observation, documentation, and literature review. All data collected were then grouped, reduced, tabulated and processed, analyzed descriptively, and statistically, in accordance with the context of the problem being studied using the SPSS 22.0 software tool.</p><p>Based on the simple linear regression analysis technique T-test (partial), R test and R square test, it was found that the value of T count (9,048) was greater than the T table (1,671), with a significance value of 0 or below the significance limit of 0.05. Both variables have a correlation coefficient of 0.765 and a coefficient of determination of 0.585. So it can be concluded that the international hotel brand image has a strong, positive, and significant influence on guest decisions to stay at the 4-star hotel in Lampung, with an effect of 58.5% while the rest, namely 41.5%, is influenced by other variables not examined in this study.</p></div><br clear="all" /><p><em> </em></p>

scholarly journals Determination of factor Xa inhibition doses of low-molecular heparin, nadroparin and reviparin in urological patients

2007 ◽  
Vol 64 (8) ◽  
pp. 538-542
Author(s):  
Svetlana Pavlovic ◽  
Sladjana Zivkovic ◽  
Goran Koracevic
Keyword(s):  
Factor Xa ◽  
Surgical Operation ◽  
Moderate Risk ◽  
Statistical Parameters ◽  
Nadroparin Calcium ◽  
The People ◽  
Factor Xa Inhibition ◽  
Significant Difference ◽  
Higher Doses

Background/Aim. The inhibition of factor Xa (FX) by the use of low-molecular heparin (LMH) is important clinical procedure in patients with moderate and high risk for the developament of venous thromboembolism (VTE) and pulmonary embolism (PE). The aim of this study was to determine the level of inhibition of FXa by the use of prophylactic doses of LMH nadroparin-calcium and reviparine-sodium which were applied in urological patients with moderate risk for VTE and PE. Methods. The examination included 80 urological patients divided into 4 groups after urological, uroradiological and anesthesiological preoperative preparation and categorization of anesthesiological risk according to the ASA III classification. The first two groups, of 20 patients each, received the recommended doses of LMH in accordance with the preoperative risk, and an inhibition of FXa 48 hours after the surgical operation and four hours after the administration of LMH was determined. Heptest and homogenous anti-Xa test were used for monitoring of FXa inhibition. Since the obtained anti-Xa values were not satisfactory, two more groups were formed and given double the recommended doses. In these new groups, inhibition of FXa was in recommended range. Standard descriptive statistical parameters were used for describing the charateristics of the people from the formed groups. Results. All the patients examined were clinically estimated as patients of moderate risk, for VTE and PE. There were no statistically singificant difference in body weight of the patients who received nadroparin-calcium 0.3 ml and reviparine-sodium 0.25 ml and those who received their double doses, respectively. The level of FXa inhibition in the group in which the dose of nadroparin-calcium of 0.6 ml was applied was statistically significantly higher than in the group which received the dose of 0.3 ml (Mann-Whitney U test: Z = 5.416; p < 0.0001). The level of FXa in the group given reviparine-sodium 0.5 ml was significantly higher than in the group which received the half of this dose (Mann-Whitney U test: Z = 5.416; p < 0.0001). This research did not confirm a statistically significant difference in the levels of FXa inhibition in patients who received nadroparincalcium as VTE and PE prophilaxis in the dose of 0.6 ml and those who received reviparin-sodium 0.5 ml (in two doses of 0.25 ml) (Mann-Whitney U test: Z = 0.163; p > 0.05). Conclusion. According to biochemical monitoring, the recommended doses of LMH are insufficient for the prophylactic inhibition of FXa in urological pateints with moderate risk for VTE and PE, so the higher doses which inhibit FXa are recommended. .

scholarly journals Predictive Algorithm for Handover Decisions between LTE and LTE-A Networks

2021 ◽  
Vol 9 (4) ◽  
pp. 110-126
Author(s):  
Wafa Benaatou ◽  
Adnane Latif ◽  
Vicent Pla
Keyword(s):  
Power Consumption ◽  
Mean Square Error ◽  
Fuzzy Inference ◽  
Hybrid Approach ◽  
Mobile Terminal ◽  
Base Station ◽  
Coefficient Of Determination ◽  
Mean Square ◽  
Statistical Parameters ◽  
Inference System

A heterogeneous wireless network needs to maintain seamless mobility and service continuity; for this reason, we have proposed an approach based on the combination of particle swarm optimization (PSO) and an adaptive neuro-fuzzy inference system (ANFIS) to forecast a handover during a movement of a mobile terminal from a serving base station to target base station. Additionally, the handover decision is made by considering several parameters, such as peak data rate, latency, packet loss, and power consumption, to select the best network for handover from an LTE to an LTE-A network. The performance efficiency of the new hybrid approach is determined by computing different statistical parameters, such as root mean square error (RMSE), coefficient of determination (R2), mean square error (MSE), and error standard deviation (StD). The execution of the proposed approach has been performed using MATLAB software. The simulation results show that the hybrid PSO-ANFIS model has better performance than other approaches in terms of prediction accuracy and reduction of handover latency and the power consumption in the network.  

Sign in / Sign up

Export Citation Format

Share Document