Journal articles: 'Efficiency coefficient'

1

Bykova, Elena V., Dmitrii P. Gavra, and Pavel A. Slutskiy. "PR Evaluation: Efficiency Coefficient." Vestnik of Saint Petersburg University. Language and Literature 14, no. 2 (2017): 275–84. http://dx.doi.org/10.21638/11701/spbu09.2017.210.

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Gnacinski, Piotr, Janusz Mindykowski, Marcin Peplinski, Tomasz Tarasiuk, Jose D. Costa, Mario Assuncao, Luis Silveira, et al. "Coefficient of Voltage Energy Efficiency." IEEE Access 8 (2020): 75043–59. http://dx.doi.org/10.1109/access.2020.2988725.

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Smith, C. D., and A. G. Oak. "Culvert inlet efficiency." Canadian Journal of Civil Engineering 22, no. 3 (June 1, 1995): 611–16. http://dx.doi.org/10.1139/l95-069.

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The results of experimental work carried out on culvert inlet efficiency at the University of Saskatchewan are reported in this paper. Efficiency is reported in terms of coefficient of discharge when the culvert operates with inlet control, and in terms of the coefficient of entrance loss when the culvert operates with outlet control. A larger coefficient of discharge or a smaller coefficient of entrance loss represents a higher efficiency. Seven different culvert inlets were tested for both inlet and outlet control, and for the headwater level both above and below the elevation of the crown of the pipe at the inlet. The results are reported in nondimensional charts. Key words: culvert flow, inlet control, outlet control, efficiency, head losses, capacity.

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Butenko, O. G. "THE COEFFICIENT OF EFFICIENCY OF HYDRAULIC CIRCUITS." Odes’kyi Politechnichnyi Universytet Pratsi 1, no. 51 (2017): 48–51. http://dx.doi.org/10.15276/opu.1.51.2017.09.

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Voronkov, O. V., and L. N. Erofeeva. "Probabilistic Material Efficiency Coefficient and Application Example." Herald of the Bauman Moscow State Technical University. Series Mechanical Engineering, no. 5 (128) (October 2019): 34–45. http://dx.doi.org/10.18698/0236-3941-2019-5-34-45.

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The paper introduces a mathematical derivation of probability density function for a random variable which is a comparative material's mass or cost efficiency coefficient. At early development stage, the coefficient allows a scientifically based selection of material, taking into account its strength or stiffness, weight or cost characteristics. A distinctive feature of the coefficient is the ability to take into account the effect on material efficiency when the material is applied to a thin-walled body structure of an important technological limitation: the discreteness of the standard range of sheet material thicknesses. This function makes it possible to determine with high accuracy the probability of the deviation of the considered random variable from its expectation not further than the limits of a given interval. The use of this function leads to a significant improvement in the developed methodology for selecting an effective material at the development stage of a thin-walled product, the methodology being previously based on the application of Chebyshev's inequality. We give an example of selecting an effective material from the list of materials considered for a cover sheet of a sandwich-panel under buckling condition.

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Galchenko, Yuriy, and Julia Ozaryan. "Methodology for quantitative assessment of ecological efficiency of geotechnologies." E3S Web of Conferences 192 (2020): 03010. http://dx.doi.org/10.1051/e3sconf/202019203010.

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The article presents the results of work aimed at solving the problem of mining waste generation by creating a methodology of wastefree technology. According to the authors, the problem of solid mining waste can be solved by building a technology with a completely closed cycle of circulation of matter. An integral non-waste coefficient for the field development technology has been proposed, which is defined as the sum of local coefficients obtained for each technological level. By the value of the general coefficient, it is possible to estimate the relative amount of solid waste for an operating mining and processing enterprise, as well as to carry out a comparative analysis of the options considered at the design stage.

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PIAZENTIN, JHONATAN, João Luis Zocoler, Camila Pires Cremasco, Alfredo Bonini Neto, and Luís Roberto Almeida Gabriel Filho. "Water Distribution Uniformity in Driping System Under Growing Pressures." International Journal for Innovation Education and Research 7, no. 11 (November 30, 2019): 14–21. http://dx.doi.org/10.31686/ijier.vol7.iss11.1829.

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Increasing water use efficiency in agricultural systems is critical as it results in economic and environmental cost reductions, especially in localized irrigation, which depends on a number of factors, especially the flow rate of the emitters and proper uniformity of water distribution, both with respect to direct with the pressure of the emitters For this evaluation the use of coefficients of water uniformity, it is essential to indicate the best wetness management. The experiment was carried out in the Irrigation laboratory, in a test stand, using Christiansen uniformity coefficient - CUC, distribution uniformity coefficient - CUD and statistical uniformity coefficient - CUE. In the irrigation line, four pressures on the drip emitter (5, 10, 15 and 20 mca) were applied. The pressure variations obtained did not reduce the efficiency of the uniformity of water distribution by the drip system, falling into high efficiency ranges for all evaluated coefficients, representing adequate wetting rates.

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Lazarević, Aleksandra, Branko Glavonjić, Leon Oblak, Miljan Kalem, and Dragan Čomić. "Analysis of Operational Efficiency of Wooden Chair Manufacturing Companies in Serbia using DEA." Drvna industrija 73, no. 1 (March 19, 2022): 81–90. http://dx.doi.org/10.5552/drvind.2022.2136.

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This paper deals with the operational efficiency of companies engaged in the production of wooden chairs using selected statistical and DEA (Data Envelopment Analysis) methods. Indicators that typically characterise the supply chain in the production of selected companies were taken as input and output variables for the DEA method. They included three input variables: inventories, material costs and production services costs and one output variable: company’s net profit. The obtained coefficients of correlation pointed to a high degree of correlation between the variables, which justified the performance of an efficiency analysis using the DEA method. The study included 12 companies engaged in the production of wooden chairs. The results of the conducted analyses show that only one company had a relatively satisfactory operational efficiency (efficiency coefficient of 0.83) for the nine-year period. All other companies, especially micro and small enterprises, had unsatisfactorily low operational efficiency. Micro enterprises had the lowest operational efficiency, with an efficiency coefficient of only 0.14. Small enterprises reached the value of 0.3, and large companies 0.67. Medium companies had the most favourable efficiency coefficient of up to 0.83.

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Bogdanov, L. A., D. K. Shishkova, M. Yu Sinitsky, and A. G. Kutikhin. "Primer parameters defining efficiency and coefficient of determination in quantitative polymerase chain reaction." Complex Issues of Cardiovascular Diseases 9, no. 3 (September 28, 2020): 13–20. http://dx.doi.org/10.17802/2306-1278-2020-9-3-13-20.

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We performed a correlation analysis between primer parameters and qPCR efficiency/coefficient of determination in two independent samples from in vitro functional experiments.Primer parameters do not define qPCR efficiency and coefficient of determination significantly if primers are designed according to the optimised PRIMER-BLAST settings.Aim. To find the correlation between the primer parameters, efficiency, and coefficient of determination (R2 ) in quantitative polymerase chain reaction (qPCR) conditions.Methods. Upon RNA isolation from primary human coronary artery endothelial cells, we performed reverse transcription-qPCR (RT-qPCR) utilising SYBR Green chemistry to measure the expression of the following genes: IL1B, IL6, CXCL8, IL12A, IL23A, PECAM1, VWF, KDR, FAPA, ACTA2, SMTN, VIM, COL4A1, MMP2, SNAI2, TWIST1, ZEB1, SCARF1, CD36, LDLR, VLDLR, VCAM1, ICAM1, SELE, SELP, CDH5, IL1R1, IL1R2, TNFRSF1A, TNFRSF1B, NOS3, PXDN. Primers were designed employing Primer-BLAST software using optimised settings. For the correlation analysis, Spearman's rank correlation coefficient was applied (GraphPad Prism).Results. Coefficient of determination correlated with the primer pair rating by Beacon Designer, amplicon melting temperature, and GC content in the reverse primer. Reaction efficiency did not correlate with the Beacon Designer rating, yet being associated with length and GC content of the reverse primer. Abovementioned correlation coefficients ranged from 0.4 to 0.5 or from -0.4 to -0.5 indicative of moderate positive or negative correlation. Other parameters did not affect reaction efficiency and coefficient of determination. Conclusion Primer parameters do not define qPCR efficiency and coefficient of determination significantly if primers are designed according to the optimised PRIMER-BLAST settings.

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Yao, Zhen Qiu, Xin Gu, and Yun Shen. "The Research of Hydrodynamic Performance for Ducted Propeller with PBCF." Applied Mechanics and Materials 733 (February 2015): 578–82. http://dx.doi.org/10.4028/www.scientific.net/amm.733.578.

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The Propeller Boss Cap Fins (PBCF) is often used to ordinary propeller, a good energy-saving effect being obtained. In order to study the energy-saving mechanism of ducted propeller with PBCF, in this paper, the FLUENT has been taken to simulate the distribution of thrust coefficient, torque coefficient, blade pressure and velocity vector of hub surface at different advance coefficients. By contrasting the results of numerical simulation of hydrodynamic performance of ducted propeller between with fins and without fins, we know that at the low advance coefficient, the ducted propeller with fins will increase the thrust coefficient and decrease the torque coefficient; rising the open water propeller efficiency, improving the efficiency under the premise of the efficiency increase by duct. The existence of fins has changed velocity distribution of water around the hub and made the water that flowed around the propeller hub with propeller rotation direction flow to propeller tail along the fins not gather in the cub, so it weakened the hub vortex.

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Butenko, О., A. Karamushko, and T. Podufala. "THE COEFFICIENT OF EFFICIENCY OF A COMPLEX HYDRAULIC CIRCUIT." Odes’kyi Politechnichnyi Universytet Pratsi 3, no. 59 (December 2019): 52–58. http://dx.doi.org/10.15276/opu.3.59.2019.07.

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Parmakli, D. M. "COEFFICIENT METHOD OF CALCULATING OF PLANNED LAND USE EFFICIENCY." Экономика сельского хозяйства России, no. 3 (2017): 85–91. http://dx.doi.org/10.32651/2070-0288-2017-3-85-91.

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13

Ogindo, H. O., and S. Walker. "The determination of transpiration efficiency coefficient for common bean." Physics and Chemistry of the Earth, Parts A/B/C 29, no. 15-18 (January 2004): 1083–89. http://dx.doi.org/10.1016/j.pce.2004.09.025.

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Shi, Jiu Sheng, Fei Peng, and Bing Wen Zhang. "The Influence of Excess Air Coefficient of Boiler Efficiency." Applied Mechanics and Materials 409-410 (September 2013): 548–52. http://dx.doi.org/10.4028/www.scientific.net/amm.409-410.548.

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Excess air coefficient has an important impact on the combustion conditions of boiler and thermal efficiency, analysis shows that the furnace temperature and the combustion efficiency is the linear relation of one to one correspondence. Any combustion conditions, there is an optimum excess air coefficient makes the top of furnace temperature, thus it can establish a control relationship, furnace temperature is optimization index, excess air coefficient is disturbance.It can achieve the purpose of improving the efficiency of boiler combustion.

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Sosnovskaya, Nina, Alena Mihaylova, and Ol'ga Cyrenova. "DETERMINATION OF THE COEFFICIENT OF EFFICIENCY OF BRIGHTENING ADDITIVES." Modern Technologies and Scientific and Technological Progress 2018, no. 1 (March 23, 2020): 48–49. http://dx.doi.org/10.36629/2686-9896-2020-2018-1-48-49.

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The influence of the concentration and structure of the organic additive on the rate of Nickel plating process is studied. The efficiency coefficient of the gloss-forming additive depending on its concentration is determined.

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Markin, A. N., and A. V. Brikov. "DEPENDENCE OF CORROSION INHIBITOR EFFICIENCY ON ITS PARTITION COEFFICIENT." Oilfield Engineering, no. 6 (2021): 60–64. http://dx.doi.org/10.33285/0207-2351-2021-6(630)-60-64.

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17

Tfwala, Cinisani M., Achamyeleh G. Mengistu, Imoh B. Ukoh Haka, Leon D. van Rensburg, and Chris C. Du Preez. "Seasonal variations of transpiration efficiency coefficient of irrigated wheat." Heliyon 7, no. 2 (February 2021): e06233. http://dx.doi.org/10.1016/j.heliyon.2021.e06233.

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18

Omocea, Ion. "The Study of Compression Engine Cycle Behavior in Terms of Variable Gazodynamic and Geometrical Configuration. Regime of the Maximum Economy." Advanced Materials Research 837 (November 2013): 147–51. http://dx.doi.org/10.4028/www.scientific.net/amr.837.147.

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In this analysis, the variable configuration requires a variable distribution. This takes account of the areas offered by the valves and resistance gazodynamic coefficients. All at once the law of efficiency variation describes the variation of the power law. Cycle behavior was analyzed for the following values of the pressure drop coefficient on admission: 5%, 10%, 20% and 40%. For the calculations is necessary to determine the dimensionless heat developed by combustion. I used the following values: for the pressure drop coefficient on admission I use ψa=10 % and for the share of gazodynamic on the suction route conductance in total conductance I use .With this configuration imposed and with (dimensionless heat developed by combustion) resulted: (mean indicated pressure cycle) ; ηv = 0,876 (cylinder filling coefficient) ; α = 1,515 (excess air coefficient) and ηi = 0,499 (indicated cycle efficiency) ; (dimensionless indicated power ); (dimensionless heat taken combustion gas) ; (dimensionless heat taken environment). After numerical analysis result a maximum efficiency with relatively low dissipation.

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19

Liu, Bin, Shengqiang Shi, Yongshan Liu, Rachid Bennacer, Aiqiang Chen, and Panagiotis E. Theodorakis. "Effect of Different Plenum-Chamber Coefficients on the Frosting of Air-Cooler." Energies 15, no. 2 (January 7, 2022): 422. http://dx.doi.org/10.3390/en15020422.

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The performance of the air-cooler in refrigeration systems plays a key role in their energy efficiency. Here, the plenum-chamber coefficient was defined to investigate a possible way of enhancing the refrigeration coefficient that reflects the efficiency of the system. To investigate the influence of the plenum-chamber coefficient on the frosting and the cooling system of the air-cooler, three plenum-chamber coefficients (0.74, 0.97, 1.2) were studied under two different relative humidities. The temperature decreasing curve of the environmental chamber, the velocity distribution of the air-cooler, and the frost accumulation under and on the air-cooler were analyzed. We find that the homogeneity of the velocity distribution of the air-cooler and the frost accumulation increase with a growing plenum-chamber coefficient, while the frost accumulation on the fin will first increase and then decrease with the increase in the plenum-chamber coefficient. In general, frosting is more present when the plenum-chamber coefficient is 0.97.

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20

Galetuse, S. "On the Highest Efficiency Windmill Design." Journal of Solar Energy Engineering 108, no. 1 (February 1, 1986): 41–48. http://dx.doi.org/10.1115/1.3268062.

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A discussion concerning the effect of profile drag on induced velocities is presented. It is concluded that Glauert’s relations for the ideal windmill are also valid for a real windmill. Using these results, the optimum conditions for induced efficiency and power coefficient are obtained. The chord distribution and the twist of the blade are then given as a function of constant K2 for highest power coefficient.

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Aoyagi, Miki. "Learning Coefficient of Vandermonde Matrix-Type Singularities in Model Selection." Entropy 21, no. 6 (June 4, 2019): 561. http://dx.doi.org/10.3390/e21060561.

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In recent years, selecting appropriate learning models has become more important with the increased need to analyze learning systems, and many model selection methods have been developed. The learning coefficient in Bayesian estimation, which serves to measure the learning efficiency in singular learning models, has an important role in several information criteria. The learning coefficient in regular models is known as the dimension of the parameter space over two, while that in singular models is smaller and varies in learning models. The learning coefficient is known mathematically as the log canonical threshold. In this paper, we provide a new rational blowing-up method for obtaining these coefficients. In the application to Vandermonde matrix-type singularities, we show the efficiency of such methods.

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Thonse Hawaldar, Iqbal, Bharat Kumar Meher, Puja Kumari, and Santosh Kumar. "Modelling the effects of capital adequacy, credit losses, and efficiency ratio on return on assets and return on equity of banks during COVID-19 pandemic." Banks and Bank Systems 17, no. 1 (March 30, 2022): 115–24. http://dx.doi.org/10.21511/bbs.17(1).2022.10.

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The study aims to determine the impact of Capital Adequacy Ratio, Credit Losses Ratio and Efficiency Ratio on the two significant profitability ratios, namely Return on Assets (ROA) and Return on Equity (ROE), during the pandemic. Panel Data Regression is used to model the effects of Capital Adequacy, Credit Losses and Efficiency Ratio on Return on Assets and Return on Equity of Indian banks. A suitable model has been developed by analyzing the results of the Hausman test and the p-values. It has been found that Capital Adequacy Ratio (CAR) with coefficient value of –0.664, CET1 with coefficient value of 1.83 and efficiency ratio with coefficient value of 1.825 have significantly affected the return on assets as their p-values are less than 0.05. However, the accepted relationship between CAR and ROA, efficiency ratio and ROA were inverse, but their coefficients were significant. The provision for credit losses (PCL) was not affecting the ROA significantly during the pandemic and hence was not considered while framing the model. Again, the dependent variable is the return on equity, except CAR. Other ratios, i.e., CET1, efficiency ratio, and PCL ratio have unacceptable correlations and are even non-significant as their p-values are less than 0.05.

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Замолодчиков, Глеб, Gleb Zamolodchikov, Р. Тумашев, R. Tumashev, Н. Щеголев, N. Schegolev, А. Фурашов, A. Furashov, Н. Семилет, and N. Semilet. "Efficiency Improvement of Industrial Fans if Operating at Off-Design Modes." Safety in Technosphere 7, no. 3 (April 1, 2019): 43–51. http://dx.doi.org/10.12737/article_5c7e34f65790a3.68014009.

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This paper’s aim is enhancement of efficiency for fans adjusting by turn of rotor blades. A high load axial fan and a fan with decreased rotor’s pitch chord ratio by reduction of blades number were investigated. Have been performed tests of the fan with design characteristics as follows: theoretical head coefficient Ht = 0,3, mass flow rate Ca = 0,4, hub’s relative diameter ν = 0.6, and with blades, graded on the law of permanent circulation. The area of effective adjustment was estimated by the performance factor value η* ≥ 0,8. When changing the stagger angles in a wide range from 26° to 70°, the area of highly economical work was in variation ranges 0,26–0,78 for the mass flow rate Ca , and 0,24–0,5 for the theoretical head coefficient Ht accordingly. Tests of fans with a reduced blades number in the rotor (12 instead of 16 for the original fan) has showed that under the same stagger angles the fan’s high-efficiency operating mode is approximately in the same range of Ca variation at slightly reduced values of theoretical head coefficient. Maximal performance factor has increased on 2.5%. Decreasing the number of rotary blades, simplifying the turning mechanism and reducing the weight are possible in the design of fans with increased values of aerodynamic load coefficients.

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Belyanovskaya, Elena, Kostyantyn Sukhyy, Roman Lytovchenko, Mikhailo Gubinskyi, Elena Prokopenko, and Oleksandr Yeromin. "Performance of Adsorptive Heat Energy Converters for Heat Supply Systems." Advances in Thermal Processes and Energy Transformation 1, no. 3 (2018): 55–60. http://dx.doi.org/10.54570/atpet2018/01/03/0055.

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This paper is devoted to performance of adsorptive heat energy converters for heat supply systems. The following calculation procedure of operating characteristics of an adsorption heat energy storage device for a decentralized space heating system is suggested: calculation of the mass transfer coefficient, adsorption amount, useful heat of adsorption, determination of the heat input, it being calculated as heat inputs for heating the adsorbent, device housing, water in the tank, evaporation of water in the tank, heating of the adsorbed water and desorption. Then coefficient of efficiency is calculated. The optimal operating conditions of the heat accumulating device which allow to operate with maximal efficiency coefficients 53 – 57 % are stated to be vapor-air flow rate 0.6 - 0.8 m/s and relative humidity of 40 – 60 %. Correlation between efficiency coefficients deduced from experiments and calculated with suggested algorithm is confirmed by the results of field trials.

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Guo, Aijun, Daiwei Jiang, Fanglei Zhong, Xiaojiang Ding, Xiaoyu Song, Qingping Cheng, Yongnian Zhang, and Chunlin Huang. "Prediction of Technological Change under Shared Socioeconomic Pathways and Regional Differences: A Case Study of Irrigation Water Use Efficiency Changes in Chinese Provinces." Sustainability 11, no. 24 (December 11, 2019): 7103. http://dx.doi.org/10.3390/su11247103.

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Technological changes in water use efficiency directly influence regional sustainable development. However, few studies have attempted to predict changes in water use efficiency because of the complex influencing factors and regional diversity. The Chinese Government has established a target of 0.6 for the effective utilization coefficient of irrigation water, but it is not clear how the coefficient will change in different provinces in the future. The purpose of this study is to predict irrigation water use efficiency changes using a conditional convergence model and combined with the shared socioeconomic pathways (SSPs) scenario settings and hydro-economic (HE) classification to group 31 Chinese provinces by their different economic and water resources conditions. The results show that the coefficient exponentially converges to 0.6 in half the provinces under SSP1 (sustainability), SSP2 (middle of the road), and SSP5 (conventional development) by 2030, whereas SSP3 (fragmentation) and SSP4 (inequality) are generally inefficient development pathways. HE-3 provinces (strong economic capacity, substantial hydrological challenges) achieve the greatest efficiency improvements (with all coefficients above 0.6), and SSP1 is a suitable pathway for these provinces. HE-2 provinces (strong economic capacities, low hydrological challenges) have relatively low efficiency because they lack incentives to save water, and SSP1 is also suitable for these provinces. For most HE-1 provinces (low economic capacity, low hydrological challenges), the coefficients are less than 0.6, and efforts are required to enhance their economic capacity under SSP1 or SSP5. HE-4 provinces (low economic capacity, substantial hydrological challenges) would improve efficiency in a cost-efficient manner under SSP2.

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Patil, Gudigopuram, Ayyildiz, Delgado, and Morrison. "Performance Evaluation and Dimensional Analysis of Multistage Helicoaxial Pump for Two-Phase Flow." International Journal of Turbomachinery, Propulsion and Power 4, no. 3 (July 25, 2019): 22. http://dx.doi.org/10.3390/ijtpp4030022.

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A four stage helicoaxial pump was tested under varying operating conditions. A range of inlet pressures, rotational speeds (3000, 3600 rpm), and gas void fractures (GVFs) were considered for two fluid viscosities. The head developed and power input to run the pump were recorded. Head, power input and efficiency decrease as the GVF increases with best efficiency point (BEP) moving towards lower flow rate conditions. Dimensional analysis was conducted to evaluate the applicability of current affinity laws to the two-phase flow performance of the pump under consideration. Dimensionless head coefficient and power coefficients were defined for two-phase flow, considering the homogeneity in the two-phase fluid properties. Deviations in the two-phase affinity coefficients from the common law curve increases with GVF. To bridge this gap, a new correlation is proposed with a revised flow coefficient that allows all the head coefficient data to collapse on a single line with a greater degree of accuracy.

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Fan, Yue Sheng, Wei Xie, Jin Tao Li, Lu Ye Li, and Hui Xin Shi. "The Effect of Ventilation Mixed Coefficient on Main Filter Efficiency." Advanced Materials Research 594-597 (November 2012): 2090–94. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.2090.

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In order to improve indoor air quality, the effect of ventilation mixed coefficient on main filter efficiency was analyzed. A mass balance equation for a well-mixed space was built. Some design equations for determination the main filtration efficiency was introduced. Because the air mixing is not perfect, the formula of air filter efficiency calculation on heterogeneous model was deduced. In addition, the relationship between ventilation parameters and the main filter efficiency was also analyzed. Through numerical calculation, the main filter efficiency under different heterogeneous coefficient is calculated. The results show that when the heterogeneous coefficient between 0.6 and 0.8, the main filter efficiency can take 1.30 to 1.80 to correct.

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Sobolewski, Mirosław, Dominika Gancarczyk, and Piotr Książek. "Efficiency of sorbents used to restore the grip of the surface of the oily road." MATEC Web of Conferences 247 (2018): 00024. http://dx.doi.org/10.1051/matecconf/201824700024.

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The use of sorbents is one of the methods most commonly used by the fire departments to remove spilled hydrocarbon liquids. Sorbents approved for use by fire brigades must meet the requirements of the Ministry of Internal Affairs. However, this requirement does not include the assessment of the degree of roughness of the road surface after removal of oily spills. The high degree of restoration of road surface grip is extremely important for the safety of road users. The article presents the results of research on the effectiveness of restoring the coefficient of friction by different sorbents. The tests were carried out for three different asphalt pavements, determining the coefficients of friction for dry, wet and oily surfaces and after applying sorbents. Static friction coefficients were determined by measuring the angle of the inclination of the tested surface specimen, at which the probe imitating the car tire slid. It turned out that none of the used sorbents fully restored the initial coefficient of friction on the asphalt surface. The use of professional sorbents allowed for the restoration of about 80% of the initial coefficient of friction of the dry surface. Significantly poorer results were obtained for the most commonly used sorptive replacement materials, i.e. sand or sawdust.

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CZYŻEWSKA, Marta, and Radosław TRĘBIŃSKI. "A Method for Predicting Efficiency of Perforated Muzzle Brakes." Problems of Mechatronics Armament Aviation Safety Engineering 12, no. 4 (December 30, 2021): 29–42. http://dx.doi.org/10.5604/01.3001.0015.5985.

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This paper presents a method for predicting a value of a gasdynamic efficiency coefficient for perforated muzzle brakes. The method is based on the interior ballistics modelling for determining gasdynamic flow parameters at the brake inlet and 2D modelling the processes inside the brake with treating vents as circumferential slots. The modelling provides information about the mass flux time changes at the inlet and at the outlet of the brake. Using this information, the mass partition coefficient values and the gasdynamic efficiency coefficient values are calculated. It has been shown that the mass partition coefficient establishes very quickly and it is determined only by the geometry of the brake. The gasdynamic efficiency coefficient establishes after a relatively long time, what demands carrying out calculations for a relatively long time period. However, it has been shown that this problem can be solved by making use of the established ratio of mass fluxes at the outlet and the inlet. So, flow parameters’ values at the inlet are sufficient for determining the gasdynamic efficiency coefficient to the moment of attaining the final value. It has been shown that this value depends on the ballistics and on the vents inclination angle.

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30

Das, Angsuman. "Coefficient of domination in graph." Discrete Mathematics, Algorithms and Applications 09, no. 02 (April 2017): 1750018. http://dx.doi.org/10.1142/s1793830917500185.

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This paper introduces a new domination parameter called coefficient of domination of a graph, which measures the maximum possible efficiency of domination for the given graph. It is evaluated for various classes of graphs and different bounds are proposed. Finally, Nordhaus–Gaddum type inequalities are established for coefficient of domination of a graph and its complement.

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Bradbury, Robert C., Joseph H. Golec, and Frank E. Stearns. "Comparing Surgical Efficiency in Independent Practice Association HMOS and Traditional Insurance Programs." Health Services Management Research 6, no. 2 (May 1993): 99–108. http://dx.doi.org/10.1177/095148489300600204.

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This study examines the effect of Independent Practice Association (IPA) HMO membership on hospital total charges, ancillary charges and length of stay (LOS) for surgical patients. Intrahospital comparisons of IPA and traditional insurance patients are made after adjusting for surgical procedure, admission severity of illness, age, sex and year of admission. Our multiple regression model indicates that IPA patients undergoing 12 frequently occurring surgical procedures have lower resource use. Eight (80%) of the 10 study hospitals exhibit a negative IPA beta coefficient for total charges, ancillary charges and LOS. Five (50%) hospitals have statistically significant (p <0.05) negative coefficients for total charges, while one (10%) hospital has a significant positive coefficient. IPA patients exhibit adjusted total charges that are 6% lower than traditional insurance, ancillary charges that are 4.3% lower, and LOS that is 10% shorter.

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Protopopov, A., A. Makhlaeva, and A. Panya. "Determination of the coefficient of economic efficiency of frequency regulator." IOP Conference Series: Materials Science and Engineering 779 (April 24, 2020): 012018. http://dx.doi.org/10.1088/1757-899x/779/1/012018.

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Karagiannis, Giannis, and Vangelis Tzouvelekas. "Measuring technical efficiency in the stochastic varying coefficient frontier model." Agricultural Economics 40, no. 4 (July 2009): 389–96. http://dx.doi.org/10.1111/j.1574-0862.2009.00386.x.

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Nowak, M., Ł. Bober, B. Borkowski, M. Kępińska, P. Szperlich, D. Stróż, and M. Sozańska. "Quantum efficiency coefficient for photogeneration of carriers in SbSI nanowires." Optical Materials 35, no. 12 (October 2013): 2208–16. http://dx.doi.org/10.1016/j.optmat.2013.06.003.

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Tian, Liang, Zhibing Yang, Fritjof Fagerlund, and Auli Niemi. "Effects of permeability heterogeneity on CO2injectivity and storage efficiency coefficient." Greenhouse Gases: Science and Technology 6, no. 1 (September 18, 2015): 112–24. http://dx.doi.org/10.1002/ghg.1540.

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Song, Zhaoyang, Changfu Wei, and Chenggang Zhao. "A new theory for membrane efficiency coefficient of compacted clay." E3S Web of Conferences 218 (2020): 02033. http://dx.doi.org/10.1051/e3sconf/202021802033.

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A new method for calculation the membrane efficiency coefficient w of compacted clay is proposed in this paper. The influence of fixed negative charge on the surface of clay minerals is considered. What’s more, the change of porosity during deformation is considered. Based on the chemical potential of specimens, the true ion concentration in pore-water is obtained. Based on the true ion concentration in pore water, the disjoining pressure considering fixed negative charge inside soils and the change of void ratio is proposed. A new calculation method for the membrane efficiency coefficient of compacted clay is established. The test data of w considering different porosity are calculated and the calculated results are compared with the traditional calculation methods. The new calculation methods of w provide a more physical-based theory for environmental geotechnical engineering.

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Sakovich, V. A. "Microdosimetric Interpretation of the Dose and Dose Rate Efficiency Coefficient." Atomic Energy 122, no. 2 (June 2017): 125–30. http://dx.doi.org/10.1007/s10512-017-0246-8.

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Fridrichová, Marcela, Iveta Hájková, and Karel Dvořák. "Efficiency of Sulphate Paste Liquefaction." Advanced Materials Research 897 (February 2014): 57–60. http://dx.doi.org/10.4028/www.scientific.net/amr.897.57.

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The aim of the research was to find and test suitable plasticizing admixtures, which have result in reduction of high water coefficient, in order to improve final technological gypsum properties from waste sources of raw material.

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Dyachkov, Ye A., and Ye A. Fedyanov. "Influence of hydraulic fluid viscosity on the efficiency coefficient of hydrodynamic transmission." Traktory i sel hozmashiny 81, no. 8 (August 15, 2014): 36–37. http://dx.doi.org/10.17816/0321-4443-65556.

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Results of laboratory investigation of influence of hydraulic fluid viscosity on efficiency coefficient of tractor hydrodynamic transmission are considered. It is shown, that efficiency coefficient is increased when hydraulic fluid viscosity decreases. Formula allowing to estimate quantitatively viscosity influence on efficiency coefficient of hydraulic converter is given.

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Wu, Zheng-Xue, Chao-Yun Long, Jing Wu, Zheng-Wen Long, and Ting Xu. "Scattering in graphene quantum dots under generalized uncertainty principle." International Journal of Modern Physics A 34, no. 31 (November 10, 2019): 1950212. http://dx.doi.org/10.1142/s0217751x19502129.

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In this article, the Dirac electron scattering problem on circular barrier of radius [Formula: see text] is studied under the generalized uncertainty principle (GUP). The expressions of scattering coefficients, scattering cross-section and scattering efficiency of massless Dirac particle are obtained by solving the massless Dirac equation under GUP and discussed by numerical methods. It shows that the scattering coefficient, the scattering cross-section, and the scattering efficiency depend explicitly on the GUP parameter [Formula: see text]. For the scattering coefficient [Formula: see text], GUP may cause slight shift in the oscillation position of [Formula: see text] and make some peaks value of [Formula: see text] smaller. For scattering cross-section and scattering efficiency, GUP may also lead to slight shift in their oscillation position and increase of amplitude when the GUP parameter increases.

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Ma, Yunbei, and Xuan Luo. "New Inference Procedures for Semiparametric Varying-Coefficient Partially Linear Cox Models." Journal of Applied Mathematics 2014 (2014): 1–16. http://dx.doi.org/10.1155/2014/360249.

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In biomedical research, one major objective is to identify risk factors and study their risk impacts, as this identification can help clinicians to both properly make a decision and increase efficiency of treatments and resource allocation. A two-step penalized-based procedure is proposed to select linear regression coefficients for linear components and to identify significant nonparametric varying-coefficient functions for semiparametric varying-coefficient partially linear Cox models. It is shown that the penalized-based resulting estimators of the linear regression coefficients are asymptotically normal and have oracle properties, and the resulting estimators of the varying-coefficient functions have optimal convergence rates. A simulation study and an empirical example are presented for illustration.

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Renzi, Massimiliano, and Mosè Rossi. "A generalized theoretical methodology to forecast flow coefficient, head coefficient and efficiency of Pumps-as-Turbines (PaTs)." Energy Procedia 158 (February 2019): 129–34. http://dx.doi.org/10.1016/j.egypro.2019.01.057.

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Хафизов, Камиль, Kamil Khafizov, Рамиль Хафизов, Ramil Khafizov, Азат Нурмиев, Azat Nurmiev, Ильгиз Галиев, and Ilgiz Galiev. "THEORETICAL BACKGROUND OF CREATING A MATHEMATICAL MODEL OF TRACTOR TRACTION EFFICIENCY." Vestnik of Kazan State Agrarian University 14, no. 3 (October 30, 2019): 116–21. http://dx.doi.org/10.12737/article_5db9748fc053c2.28431294.

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To identify the main parameters of the tractor - its mass, engine power, wheel diameter and its profile width (four-parameter optimization) using the optimization criterion - the total energy costs (taking into account the energy of the crop lost due to the non-optimality of these parameters), it is necessary to have a mathematical model for calculation of engine power through the traction coefficient of performance of the tractor. The traction efficiency of the tractor is calculated through f is the coefficient of resistance to rolling of the tractor wheel and d is the coefficient of slipping of the tractor wheel. An analysis of the applied theory developed by previous researchers showed that the values f and d depend on the weight of the tractor coming to one wheel G, the diameter D and the width of the profile of the wheel B, the pressure in its tires ρw, the hardness of the soil H, the effort on the tractor hook Pkp and its speed V. During the analysis, it was found that the larger the diameter of the wheel, the width of the tire profile, the less the vertical load on the wheel and the pressure in the tires, the less the resistance to rolling the wheel over the soil being compacted. It is concluded that the study of the nature of the change in the coefficient of resistance to rolling wheels f and their slipping d from the above factors must be carried out jointly, because they influence each other. The absence of acceptable mathematical dependences for calculating the indicated coefficients, with the simultaneous action of all identified factors, leads to the need for a seven-factor experiment to identify the dependencies f =j (G, D, b, ρw, H, Ркр, V) and δ =ψ (G, D, b, ρw, H, Ркр, V), which is very difficult in operating conditions, therefore, using the similarity theory, it is necessary to reduce the number of factors in the experiment to four.

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O S, Aina, Yakubu S A, Odegbade O O, Dada A A, and Sangodare A O. "Economic efficiency of fish farming in ondo state, nigeria." Journal of Management and Science 11, no. 2 (June 30, 2021): 40–45. http://dx.doi.org/10.26524/jms.11.13.

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This study assessed economic efficiency of fish farming in Ondo State, Nigeria. The study used primary and secondary data to achieve the objective of the study. Primary data were collected with the aid of structured questionnaire from 72 Fish farmers selected using the multistage sampling technique. The analytical technique involved budgeting technique, stochastic frontier production and cost function analysis. The study discovered from the gross margin and net-revenue analysis that fish production was profitable judging by the positive value and size of the gross margin (₦175.55 per kg) and net revenue (₦170.96 per kg). The result of the stochastic frontier production function analysis showed that all the regressors used in the analysis had positive coefficient, indicating that allthe inputs considered had direct relationship with farmers output. The result of the stochastic cost frontier function analysis showed that unit cost of labour, fingerlings, fertilizer and lime had positive regression coefficients, indicating that as these variables increase,the overall production cost of fish increases. The result also indicated that the presence of technical inefficiency had effects on fish production as depicted by the significant estimated gamma coefficient. The study recommends improvement in human capital development through education policy and training programme by extension education, opening of more market opportunities should be pursued and government should provide support to fish farmer’s cooperative society by increasing their capital base.

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Zhao, Qi, Chen Wang, and Feng Yi Han. "Performance Analysis of the Absorption Heat Pump Systems Based on the Entransy Theory." Applied Mechanics and Materials 584-586 (July 2014): 2179–83. http://dx.doi.org/10.4028/www.scientific.net/amm.584-586.2179.

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The entransy efficiency expression of the absorption heat pump systems was defined in this paper, combined with the concept of the entransy and based on the model of a four temperature level absorption heat pump cycle. The relationship between the heating coefficient of the absorption heat pump and heating rate with the changes of the entransy efficiency was deduced. Numerical example was introduced to analysis the impactions of the entransy efficiency on the absorption heat pump systems. The results show that the heating coefficient increases with the growth of entransy efficiency, the entransy efficiency and the heating rate becomes larger when the value u gets larger, but the heating coefficient gets smaller. The heating rate decreases with the growth of the heating coefficient, the value u has more impaction on the heating rate when the heating coefficient remains constant.

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Zhu, Jianyang. "The Effect of Damping Coefficient, Spring Coefficient, and Mass Ratio on the Power Extraction Performance of a Semiactive Flapping Wing." International Journal of Aerospace Engineering 2019 (April 16, 2019): 1–12. http://dx.doi.org/10.1155/2019/5151808.

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The effect of varying damping coefficient C∗, spring coefficient K∗, and mass ratio M∗ on the semiactive flapping wing power extraction performance was numerically studied in this paper. A numerical code based on Finite Volume method to solve the two-dimensional Navier-Stokes equations and coupled with Finite Center Difference method to solve the passive plunging motion equation is developed. At a Reynolds number of 3400 and the pitching axis at quarter chord from the leading edge of the wing, the power extraction performance of the semiactive flapping wing with different damping coefficient, spring coefficient, and mass ratio is systematically investigated. The optimal set of spring coefficient is found at a value of 1.00. However, the variation of mass ratio M∗ cannot increase the maximum mean power coefficient and power efficiency, but it can influence the value of damping coefficient C∗ at which the wing achieves the maximum mean power coefficient and power efficiency. Moreover, insensitivity of the mean power coefficient and power efficiency to the variation of damping coefficient C∗ is observed for the wing with smaller mass ratio, which indicates the wing with smaller M∗ has better working stability.

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Helta, Mirosław. "Efektywność techniczna spółek Agencji Nieruchomości Rolnych w latach 1994-2012." Roczniki Naukowe Ekonomii Rolnictwa i Rozwoju Obszarów Wiejskich 104, no. 2 (August 15, 2017): 23–34. http://dx.doi.org/10.22630/rnr.2017.104.2.10.

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The aim of the study was to determine the effectiveness of strategic companies owned by the Agricultural Property Agency in the period 1994-2010 using the DEA method. Between 1994 and 2012 the technical efficiency factors of CCR, BCC and coefficients of scale efficiency were characterized by a growing trend. In the universe of objects of the CCR, between 1994 and 2012 the technical coefficient of performance rose from 57.7 to 82.6%. The technical efficiency factors of the BCC ranged from 67.2% to 91.5% during the period, and scale efficiency ratios were respectively 87.0% and 90.4%. In the analysed groups of objects, the objects included in the plant breeding group (HR) and the animal breeding group (HZ) were characterized by the highest technical efficiency of CCR,BCC and scale performance. The lowest coefficients of technical efficiency were observed in the horse stables (SK).

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Zhang, Yubing, Yong Wang, Guang Sun, Jiazhen Han, and Yudong Xie. "EFFECTS OF TWO TYPES OF CONTROLLABLE DEFORMATION ON ENERGY EXTRACTION OF A FLEXIBLE HYDROFOIL." Brodogradnja 73, no. 1 (January 1, 2022): 109–26. http://dx.doi.org/10.21278/brod73106.

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Energy extraction capacity of controllably flexible hydrofoil was studied under two identified deformation modes. Deformation modes, flexure parameters (flexure amplitude  and flexure coefficient ) and motion parameters (reduced frequency f* and pitching amplitude 0) were investigated to understand the effects of controllably flexible deformation on energy extraction. The results reveal that deformation modes affect the effective angle of attack and vortex structure, which influence hydrodynamic performance. The energy extraction capacity improves from the deformation mode 2 to the rigid hydrofoil and then to the deformation mode 1. Under the deformation mode 1, lift, moment and power coefficients are increased obviously with the increase of , while they increase slightly with . Power coefficients and efficiency are sensitive to , which influences the development of leading-edge vortices. The flexible coefficient  affects the wake structure, which has less impact on variation of force coefficient. As the increase in f*, averaged power coefficients firstly increase and then decrease. Further, the optimal f* is subjected to 0. Interestingly, a critical reduced frequency f*s, which is generally increase with increasing 0, was found under three modes. The condition that f* > f*s. is a prerequisite for subsequent adjustments of flexure modes and parameters according to different requirement of power coefficient under different tidal currents. The range of high efficiency () is: deformation mode 1 (36.1%<<54.3%) > rigid hydrofoils (34.2%<<41%) > deformation mode 2 (26.9%<<30.3%).

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Yu, Hua Ming. "Factor Analysis and Regression of the Air Source Heat Pump Water Heater Energy Efficiency Coefficient." Applied Mechanics and Materials 727-728 (January 2015): 489–92. http://dx.doi.org/10.4028/www.scientific.net/amm.727-728.489.

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Using the orthogonal experiment method, the factors of air source heat pump water heater energy efficiency coefficient (COP) were analyzed. It was determined that the temperature of water influenced the energy efficiency coefficient the most, then the surrounding temperature and the surrounding humidity. Regression equation about the energy efficiency coefficient was obtained and was testified to be of great significance to industrial production.

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Taslim, M. E., and V. Nezym. "A New Statistical-Based Correlation for the Rib Fin Effects on the Overall Heat Transfer Coefficient in a Rib-Roughened Cooling Channel." International Journal of Rotating Machinery 2007 (2007): 1–11. http://dx.doi.org/10.1155/2007/68684.

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Heat transfer coefficients in the cooling cavities of turbine airfoils are greatly enhanced by the presence of discrete ribs on the cavity walls. These ribs introduce two heat transfer enhancing features: a significant increase in heat transfer coefficient by promoting turbulence and mixing, and an increase in heat transfer area. Considerable amount of data are reported in open literature for the heat transfer coefficients both on the rib surface and on the floor area between the ribs. Many airfoil cooling design software tools, however, require an overall average heat transfer coefficient on a rib-roughened wall. Dealing with a complex flow circuit in conjunction with180∘bends, numerous film holes, trailing-edge slots, tip bleeds, crossover impingement, and a conjugate heat transfer problem; these tools are not often able to handle the geometric details of the rib-roughened surfaces or local variations in heat transfer coefficient on a rib-roughened wall. On the other hand, assigning an overall area-weighted average heat transfer coefficient based on the rib and floor area and their corresponding heat transfer coefficients will have the inherent error of assuming a 100% fin efficiency for the ribs, that is, assuming that rib surface temperature is the same as the rib base temperature. Depending on the rib geometry, this error could produce an overestimation of up to 10% in the evaluated rib-roughened wall heat transfer coefficient. In this paper, a correction factor is developed that can be applied to the overall area-weighted average heat transfer coefficient that, when applied to the projected rib-roughened cooling cavity walls, the net heat removal from the airfoil is the same as that of the rib-roughened wall. To develop this correction factor, the experimental results of heat transfer coefficients on the rib and on the surface area between the ribs are combined with about 400 numerical conduction models to determine an overall equivalent heat transfer coefficient that can be used in airfoil cooling design software. A well-known group method of data handling (GMDH) scheme was then utilized to develop a correlation that encompasses most pertinent parameters including the rib geometry, rib fin efficiency, and the rib and floor heat transfer coefficients.

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Journal articles on the topic 'Efficiency coefficient'

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