Coefficients Of Regression Equations Research Articles

Methodology and precision research of wind farm power prediction

The article presents a newly developed statistical regression wind farm power change prediction model. Results of the research and the data analysis performed show that the model is able to evaluate factors determining the wind farm gross output and to increase the prediction accuracy. The influence of the regression equation independent variables on the dependent one is determined by the means of the Students t-test, and the levels of varying equation coefficients are established. The transformation of weather density and wind speed product corresponding to the linear stochastic dependence of the variable power characteristic part for the wind power plant is estimated. Expression of the transformation is suitable to use for predicting the wind farm power in the range from the minimum values to the installed ones. The statistical regression model of the wind farm power prediction is presented on the basis of given technique of the linear regression analysis, the exponential regression equation, and variable coefficients of regression equation. Results of power prediction by the given model precision research show that the one-day relative average prediction error does not exceed 7.52 % of the installed value. DOI: http://dx.doi.org/10.5755/j01.eie.23.1.12837

Correlation between physicochemical properties of modified clinoptilolite and its performance in the removal of ammonia-nitrogen.

The physicochemical properties of the 24 modified clinoptilolite samples and their ammonia-nitrogen removal rates were measured to investigate the correlation between them. The modified clinoptilolites obtained by acid modification, alkali modification, salt modification, and thermal modification were used to adsorb ammonia-nitrogen. The surface area, average pore width, macropore volume, mecropore volume, micropore volume, cation exchange capacity (CEC), zeta potential, silicon-aluminum ratios, and ammonia-nitrogen removal rate of the 24 modified clinoptilolite samples were measured. Subsequently, the linear regression analysis method was used to research the correlation between the physicochemical property of the different modified clinoptilolite samples and the ammonia-nitrogen removal rate. Results showed that the CEC was the major physicochemical property affecting the ammonia-nitrogen removal performance. According to the impacts from strong to weak, the order was CEC>silicon-aluminum ratios>mesopore volume>micropore volume>surface area. On the contrary, the macropore volume, average pore width, and zeta potential had a negligible effect on the ammonia-nitrogen removal rate. The relational model of physicochemical property and ammonia-nitrogen removal rate of the modified clinoptilolite was established, which was ammonia-nitrogen removal rate=1.415[CEC]+173.533 [macropore volume]+0.683 [surface area]+4.789[Si/Al]-201.248. The correlation coefficient of this model was 0.982, which passed the validation of regression equation and regression coefficients. The results of the significance test showed a good fit to the correlation model.

Application of purchasing power parity indices for studying inflation processes in Ukraine

This article focuses on the problem of applying the Big Mac index as a meaningful indicator that characterizes the state of the economy as a whole, as well as on determining the relationship between such economic indicators as exchange rate, inflation index and money supply (the NBU aggregate М3) in Ukraine. The sample of the countries was analyzed and the countries with the highest and lowest value of “Big Mac” were determined. Moreover, there is a possibility of using the “Big Mac” index as a measure of undervaluation or overvaluation of the currency, conclusions for specific countries were made. The clustering method is applied, which allows selecting clusters and constructing a Kohonen’s network. For the clustering procedure the following sample of countries and factors was drawn: GDP, annual inflation and the value of the “Big Mac”. As a result, three clusters were formed and the key factor for their formation was GDP. In addition, clusters differ in the level of annual inflation and the value of the “Big Mac”. There was determined a relationship between the value of the “Big Mac”, the exchange rate, the inflation index and aggregate M3of the NBU in Ukraine. A correlation analysis was conducted and corresponding trend lines characterized by regression equation and high coefficient of determination were selected. A multiple linear model reflecting simultaneously the dependence of the value of the “Big Mac” on the exchange rate, the inflation index and the money supply was built. Verification of the model by the criteria of relevance and adequacy showed its quality and possibility of applying it to forecasting. The dynamics of the Ukrainian “borscht” index which can be considered similar to the “Big Mac” index was considered. A time-series of these indices were compared and their dynamics was analyzed.

Study of the predominant defect development in rails of underground systems after preventive grinding and lubrication

In order to determine the method of contact surface treatment and to define the rational surface roughness in the wheel/rail contact for the minimal growth rate of contact fatigue defects the program of experiments in operational conditions was developed. On the basis of the results and calculations the coefficients of regression equations, which describe dependencies of the wear rate on the parameters of the contact surface treatment in real operational conditions were obtained. Besides, the diagrams of dependencies of the friction coefficient on the roughness of railhead contact surface of the high rails with and without lubrication, when laid in curves of underground systems, were built. The experiments conducted in operational conditions of Kharkiv Metro revealed the influence of roughness of the railhead side surface of the high rails in curves on the contact fatigue defect development after preventive grinding and lubrication. According to the results of the experiments it was established that the rail preventive grinding with simultaneous lubrication led to slower contact fatigue defect development in rails of underground systems. The rational roughness of the railhead side surface of the high rails in curves after preventive grinding, which led to the minimal rate of defect development, was defined.

Formula to detect high sodium excretion from spot urine in chronic kidney disease patients.

Excessive sodium intake is related to adverse renal and cardiovascular outcomes in patients with chronic kidney disease (CKD) and assessment of sodium intake is complex and not evaluated very often in clinical practice. To develop a new formula to estimate 24h sodium excretion from urine sample (second void) of patients with CKD. We included 51 participants with CKD who provided 24-hour urine collection and a sample of the second urine of the day to determine the sodium excretion. A formula to estimate the 24-hour sodium excretion was developed from a multivariate regression equation coefficients. The accuracy of the formula was tested by calculating the P30 (proportion of estimates within 30% of measured sodium exection) and the ability of the formula to discriminate sodium intake higher than 3.6 g/day was evaluated by ROC curve. Correlation test between measured and estimated sodium was significant (r = 0.57; p < 0.001), but P30 test identified a low accuracy (61%) of the formula. Different cutoff points were tested by performance tests and a ROC curve was generated with the cutoff that showed better performance (3.6 g/day). An area under the curve of 0.69 with a sensitivity of 0.91 and specificity of 0.53 was obtained. A simple formula with high sensitivity in detecting patients with sodium consumption higher than 3.6 g/day from isolated urine sample was developed. Studies with a higher number of participants and with different populations are necessary to test formula´s validity.

Identifying pitching mode of aerial planting projectile by the use of image processing

Aerial planting is a new and affordable method, which is used for purposes of reforestation and restoring pastures. In this study, flight dynamics of an aerial planting projectile has been simulated using data of the wind tunnel test. By creating the projectile graphical model and using the results of dynamic equations for this model, pitching angle has been simulated graphically by recording the pitch attitude of the graphical model and, by applying spectral filtration the rate of pitch angle at any point of the trajectory is calculated. Primary dynamic model parameters including the coefficients of regression equation of motion are estimated by applying the least squares estimator. Comparison of the estimated coefficients from image processing and coefficients given to the simulation program reveals high accuracy of the model resulting from the image processing data used in this method and approves wind tunnel test data by graphical model and calibration of camera measurement. Also, an experimental test setup has been created and the images of projectile falling down in the presence of fan flow have been captured with high-speed digital camera. By decreasing the ambient light intensity, the images and measurement noise of theta angle increases. By applying recursive least square algorithm, sensitivity of coefficients and robustness of this algorithm has been analyzed. The analysis results indicate that the estimation of coefficients using image processing data has great accuracy.

Results of experimental studies of mixing process in a horizontal ribbon mixer

The performance of livestock farms and complexes largely depends on the quality of feed preparation for feeding. It is proved that feeding efficiency is increased with the use of feed mixtures in the diet, which allows to increase animal performance, to reduce feeding period and feed consumption per production unit. Despite of the wide use of different types of mixers, their working process is understudied, and therefore the study of influence of design and technological parameters of mixers on the quality characteristics of mixture is the crucial task. The aim of the study is the improvement of technological process of feed mixtures preparation in a horizontal ribbon mixer by improving quality of mixing and reducing energy intensity of working process. Experimental studies of a horizontal ribbon mixer were carried out in the laboratory of mechanization of animal husbandry at the Zonal Research Institute of Agriculture of the North-East. For the studies, the mixture consisting of a basis (80% of barley and 20% of rye) and a control component (pea) was used. The implementation of multifactorial experiment allows to obtain approximate mathematical models of the process, that link together all the factors taken into account. Experimental studies allow to determine the numerical values of coefficients of regression equations, by which it is possible to assess the degree of influence of relevant factors. During the tests, Box-Behnken design matrix was implemented. According to the results, the maximum value of the uniformity coefficient of finished product is 86,1%, which meets the zootechnical requirements for feeding of cattle and poultry, and is achieved in the presence of 620 kg of basis and 146 kg of control component in the mixture. The mixing time is 4 minutes, and the throughput capacity of mixer is 5,75 t/h, when the specific energy consumption is 1,55 kilowatt-hours per ton.

Estimating aboveground biomass of Trifolium repens community using measuring plates.

Aboveground biomass is an important indicator of grassland community. Direct harvesting has a great damage to the fragile ecosystem. In order to estimate the aboveground biomass of Trifolium repens community more effectively without destroying herbaceous community, various handmade measuring plates were used to study the community height and aboveground biomass of T. repens community in Duzhai Village, Dazhai Town, Yangling Zone, Shaanxi Province. Measuring plates used for trials were made of 17 kinds of specifications of aluminum-plastic and polymer plates. The plate was laid flat on the community crown, the height of plant community from ground level to the plate was measured and recorded, and measurements were repeated 20 times for each specification of plate. Then the plants of whole areal part below the measuring plate were cut to ground level from the corresponding quadrat, and the biomass was obtained after oven-drying and weighing. Finally, the modeling and correlation analysis were made, and the best estimate model was verified. The results showed that multiple regression equations were established with aboveground biomass of corresponding area as dependent variable, and community height below the measuring plate as indepen-dent variable. The independent variable was positively correlated with the dependent variable, and the determination coefficients, R2, ranged from 0.37 to 0.76. Compared with the polymer plates, the aluminum-plastic plates performed better on coefficients of variation of biomass, determination coefficients of regression equations, R2, and degree of accuracy. The best measuring plate was circular aluminum-plastic plate with diameter of 35 cm, and its best regression model was y=1.6460x-3.3462, where the R2 was 0.76 and the prediction accuracy was 92.1%.

Research on Cutting Force of Corner Milling of Inclined Plane

When milling corners in high speed, it will lead the mutation of cutting force that affects the processing quality and processing efficiency. In order to study the influence of milling parameters on milling force in the corner. Firstly, an orthogonal experimental of corner is designed to study the influence of various cutting parameters on cutting force. Axial cutting depth, radial depth, spindle speed and feed speed, as the major influence factors, impact on cutting force in corner milling. Then, a cutting force model of corner is established based on a method of orthogonal experiment linear regression. The significance test of regression equation and regression coefficient shows that cutting force model is accurate. The cutting force model is used to predict the cutting force, and then select the appropriate cutting parameters.

Regression analysis for solving diagnosis problem of children's health

The paper includes results of scientific researches. These researches are devoted to the application of statistical techniques, namely, regression analysis, to assess the health status of children in the neonatal period based on medical data (hemostatic parameters, parameters of blood tests, the gestational age, vascular-endothelial growth factor) measured at 3-5 days of children's life. In this paper a detailed description of the studied medical data is given. A binary logistic regression procedure is discussed in the paper. Basic results of the research are presented. A classification table of predicted values and factual observed values is shown, the overall percentage of correct recognition is determined. Regression equation coefficients are calculated, the general regression equation is written based on them. Based on the results of logistic regression, ROC analysis was performed, sensitivity and specificity of the model are calculated and ROC curves are constructed. These mathematical techniques allow carrying out diagnostics of health of children providing a high quality of recognition. The results make a significant contribution to the development of evidence-based medicine and have a high practical importance in the professional activity of the author.

Effect the tungsten(VI) and molybdenum(VI) ions on the electrical conductivity of ammonium hydroxide solutions

The effect of the W(VI) and Mo(VI) ions on the electrical conductivity of ammonium hydroxide solutions (7 mol/L) is studied in the tungsten or molybdenum concentration range 0.1–0.5 mol/L and the temperature range 20–60°C. The electrical conductivities of the solutions are shown to depend linearly on the solution temperature and the metal concentration, and the coefficients of linear regression equations are calculated. The temperature coefficients of the electrical conductivities of the solutions are determined.

Phosphate solubilizing activity of Pseudomonas fluorescens PSM1 isolated from wheat rhizosphere

A study was designed to screen and analyze the efficient phosphate solubilizing bacteria (PSBs) from wheat rhizosphere. Five biovars of Pseudomonas fluorescens (PSM1, PSM2, PSM3, PSM4 and PSM5) were isolated from wheat rhizosphere and Bacillus megaterium MTCC 8755 procured from microbial type culture collection (MTCC) Chandigarh, India. The P. fluorescens biovar PSM1 was observed to be most efficient phosphate solubilizer. Inoculation of P. fluorescens PSM1 and B. megaterium MTCC 8755, alone and in combination, caused the highest phosphate solubilization at pH 5. At this pH, maximum phosphate solubilization was observed with B. megaterium MTCC 8755 inoculation (8.2 mg mL-1) on sixth day of incubation with P. fluorescens PSM1 (8 mg mL-1) on seventh day of incubation and with dual bacterial treatment (10.5 mg mL-1) on the fourth day of incubation. A correlation coefficient of linear regression equation of phosphate solubilization with pH indicated that pH value of the medium was directly correlated with tricalcium phosphate solubilization. The study will help in choosing soil pH specific PSB inoculant for optimizing plant growth.

The Rapid and Sensitive Quantitative Determination of Galactose by Combined Enzymatic and Colorimetric Method: Application in Neonatal Screening.

The quantitative measurement of galactose in blood is essential for the early diagnosis, treatment, and dietary monitoring of galactosemia patients. In this communication, we aimed to develop a rapid, sensitive, and cost-effective combined method for galactose determination in dry blood spots. This procedure was based on the combination of enzymatic reactions of galactose dehydrogenase (GalDH), dihydrolipoyl dehydrogenase (DLD), and alkaline phosphates with a colorimetric system. The incubation time and the concentration of enzymes used in new method were also optimized. The analytical performance was studied by the precision, recovery, linearity, and sensitivity parameters. Statistical analysis was applied to method comparison experiment. The regression equation and correlation coefficient (R (2)) were Y = 0.0085x + 0.032 and R (2) = 0.998, respectively. This assay exhibited a recovery in the range of 91.7-114.3% and had the limit detection of 0.5mg/dl for galactose. The between-run coefficient of variation (CV) was between 2.6 and 11.1%. The within-run CV was between 4.9 and 9.2%. Our results indicated that the new and reference methods were in agreement because no significant biases exist between them. Briefly, a quick and reliable combined enzymatic and colorimetric assay was presented for application in newborn mass screening and monitoring of galactosemia patients.

A Study on Branding of Eggs in Select Areas of Tamilnadu

This study was initiated with the motive to check branding of eggs in select areas of Tamilnadu. A total of 100 customers, 20 retailers and 20 producers had been chosen and obtained their views on the branding of eggs. Data were collected by presenting well-structured questionnaire in the hands of respondents. Chi-square test, factor analysis, regression equation coefficient, and mean scores analysis were used to analyze the data. Results revealed that there is significant relationship exists between demographic profile of customers and their awareness on branded eggs. Factor analysis confirmed that brand, egg variants, egg content, food preparation and egg price relatively influenced on egg buying behaviour of customers. Retailers opined that there is no significant difference between the sale of branded and non-branded eggs. There is ample scope for egg producer to sale their egg under a brand name. It is concluded that customers are not completely aware about the sale of branded egg, but for consumption purpose often consider many variables. Retailers are preferred to sell non-branded eggs to low price segment and branded eggs to high quality segment. Concentrating on brand building will yield extra-ordinary returns to the producers.

Adsorption of lead (II) ions onto diatomite from aqueous solution: Mechanism, isotherm and kinetic studies

&lt;div&gt; &lt;p&gt;This study presents an evaluation of diatomite as a low cost adsorbent for Pb (II) removal from aqueous solutions under various conditions. The results demonstrate that adsorption of Pb (II) is strongly dependent on the pH of the solution. The effect of pH on adsorption of Pb (II) on diatomite was studied by varying pH from 2 to 12 at 20 &lt;sup&gt;o&lt;/sup&gt;C. In the pH range of 2.0-4.0, the percentage of Pb (II) adsorbed increases slightly as the pH increases. At pH&amp;gt;4, the percentage of Pb (II) adsorbed decreases with increasing pH because hydrolysis and precipitation begin to play an important role in the sorption of Pb (II). At pH 4, the maximum adsorption capacity of diatomite was found to be 26 mg/g. The adsorption isotherms of Pb (II) on diatomite can be described well by the Freundlich model. The regression equation coefficients were calculated and the data fitted to a second-order kinetic equation for removal of Pb (II) ions. The high adsorption capacity of diatomite makes it a suitable low-cost material for the removal of Pb (II) from aqueous solutions.&lt;/p&gt; &lt;/div&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;

Effect of Selected Parameters on Process Efficiency and Energy Consumption During the Extrusion-cooking of Corn-rice Instant Grits

Abstract More and more people begin to pay attention to how foodstuffs are produced. Due to the changing lifestyle, consumers seek products that do not require long preparation. The extrusion-cooking process responds to this type of applications with an easy management of processing promising product stability and quality. Extrusion-cooking involves the extruding of granular material under high pressure and high temperature. Such a method of treatment of raw materials makes extrudates produced from natural ingredients, i.e. corn or rice, suitable for direct consumption and guarantees their prolonged shelf-life. In our study, mixtures for instant grits were prepared from corn with a rice additive of 25% and 50%. Extrudates were prepared using a single-screw extruder TS-45 (L/D=12:1). The range of the temperatures of the extrusion process was 125/130/135 °C. The process was carried out with the variable screw rotation speed of 80, 100 and 120 rpm. This paper presents the results of process efficiency and energy consumption during the extrusion-cooking of instant corn-rice grits. Based on a bidirectional analysis of variance, the process efficiency, regression equation and correlation coefficients were determined for evaluating the impact of the processing conditions on selected properties.

Development of a Sol Particle Homogeneous Immunoassay for Measuring Full‐Length Selenoprotein P in Human Serum

Selenoprotein P (SeP), a selenium-rich extracellular glycoprotein, is the primary selenoprotein in the plasma. SeP plays an important role in the maintenance of selenium levels in the peripheral tissues. We developed a new sol particle homogeneous immunoassay (SPIA) for measuring full-length SeP (FL-SeP) levels in the human serum. We used colloidal gold particles coated with two types of anti-SeP monoclonal antibodies, one recognizing the N-terminal side domain of SeP and the other recognizing the C-terminal side domain. The assay range was 0.2-9 mg/l, and the linearity was excellent. The within-day and between-day coefficients of variation ranged from 0.73% to 2.24% and 0.45% to 1.11%, respectively. Serum samples (n = 200) were examined using the newly developed assay system (employing a Model 7070 Hitachi automatic clinical analyzer) and the conventional enzyme-linked immunosorbent assay. These two methods were compared using the Passing-Bablok regression analysis; the resulting regression equation and correlation coefficient were y = 0.940x + 0.165 and r = 0.954, respectively. Our new SPIA assay is a fully automated homogeneous immunoassay that can be used in conjunction with various commercial analyzers. The assay was sensitive, precise, and suitable for clinical measurement of the FL-SeP in the human serum.

Effect of Temperature on Dynamic Viscosity and Activation Energy of Milk and Acidophilus Milk

This article is focused on temperature dependencies of rheological parameters as the dynamic viscosity and activation energy of milk and acidophilus milk. Viscosity measurement was performed using a single-spindle viscometer. The relations of dynamic viscosity and activation energy in the temperature range 5–25 oC for milk and acidophilus milk were measured. The relations of all physical parameters of milk to temperature showed the influence of relative fat content. The effect of temperature on milk and acidophilus milk parameters is shown in Fig. 1–4. In the measured temperature interval, dynamic viscosities of milk ranged between 2.0 mPa.s and 1.3 mPa.s, and of acidophilus milk between 443.4 mPa.s and 244.1 mPa.s. Measured relations of dynamic viscosity for milk and acidophilus milk during temperature stabilisation had an exponential decreasing progress (Fig. 1–2), which is in accordance with Arrhenius equation. Temperature dependencies of activation energy are described by linear increasing functions (Fig. 3–4). Obtained values of activation energy were in the range 356.97–1267.70 J/mol for milk and in the range 615.94–2129.96 J/mol for acidophilus milk. The mathematical description of the dependencies is summarised by regression equations 2 and 3. Coefficients of regression equations and coefficients of determination approximately in the range 0.984–0.999 are presented in Table 1.

English

2 ABSTRACT: Lignin biomass was obtained from black liquor, using acid H3PO4. The residue so obtained was used for preparation of soil conditioner by artificial ammoxidation process in a batch reactor. The process parameters identified were composition of oxidizing agent (H2O2+ammonia), reaction time, and temperature. The present study also encompasses optimization of process parameters involved by the application of response surface methodology (RSM), so as to understand the interaction of these parameters. The statistical significance of the model equation was evaluated by the F-test for analysis of variance, which showed that the model is statistically significant at 95% confidence level. The model F-value of 228.48 for ammoxidation process implied that the model was statistically significant. To test the fit of the model, the regression equation and determination coefficient, R 2 were evaluated. In this case, the value of the determination coefficient R 2 = 0.9942 indicated that the model could explain 99.42% of the variability.

Determination of Gentamicin Residual in Duck Meat Using Fluorescence Analysis Method

Gentamicin is a kind of aminoglycoside antibiotics and widely used in the prevention and treatment of the duck diseases. A prediction model was established for the rapid detection of Gentamicin residue in duck meat using fluorescence analysis method according to the strong fluorescent characteristic of the generated derivative for Gentamicin and o-phthaldialdehyde (OPA) in the presence of emulsifier OP-10 and mercaptoethanol.The fluorescence spectra of the duck meat containing Gentamicin were analyzed, the optimum excitation wavelength of the material was 340 nm and the optimum emission wavelength was 442 nm. Fluorescence intensity and the concentration of the standard samples presented the good linear relationship, the linear correlation coefficient was 0.9963 and the limit of detection was 0.47 μg/mL in the dynamic rang of 0.5 ~6.5μg/mL. The correlation coefficient of regression equation was 0.9968 for the samples of duck meat extract. The experimental results showed that the fluorescence analysis method had a good performance and accuracy in detecting the Gentamicin residue in duck meat.