scholarly journals Application of a central composite face-centered design in the optimization of an Archimedean hydrokinetic turbine

2021 ◽  
Vol 19 ◽  
pp. 418-422
Author(s):  
J. Betancour ◽  
◽  
L. Velasquez ◽  
L.Y. Jaramillo ◽  
E. Chica ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Power Coefficient ◽  
Coefficient Of Determination ◽  
Significance Level ◽  
Hydrokinetic Turbine ◽  
Hydraulic Design ◽  
Face Centered ◽  
6 Degrees Of Freedom ◽  
Composite Face ◽  
Central Composite

Currently, in the literature, there are no general guidelines for the optimal hydraulic design of Archimedean screw turbines (AST) used in hydrokinetic applications. Therefore, this study is aiming at selecting the most significant geometric factors, such as the diameter ratio between the inner (𝐷𝑖 ) and the outer (𝐷𝑜) diameters (i.e., 𝐷𝑖/𝐷𝑜), the axle length (𝐿) and the blade stride (𝑝), influencing the AST performance by using a central composite face-centered (CCF) experimental design combined with the response surface methodology (RSM). The statistical analysis of variance (ANOVA) test identified with a significance level of 0.05 that the most significant variables on the performance of the turbine were 𝑝 and 𝐷𝑖/𝐷𝑜. The AST efficiency was evaluated by means of the power coefficient (𝐶𝑃), which was calculated by means of computational fluid dynamics (CFD) methods coupled with the 6-degrees of freedom (6-DoF) approach. The second-order polynomial model was used to predict the 𝐶𝑃 and the coefficient of determination (𝑅 2 ) was found to be 97.4%.

scholarly journals OPTIMIZING THE PROCESS OF TRANSFORMING COFFEE HUSKS INTO BIOCHAR BY MEANS OF HYDROTHERMAL CARBONIZATION

2018 ◽  
Vol 54 (4B) ◽  
pp. 138
Author(s):  
Tran Thi Hien
Keyword(s):  
Maximum Yield ◽  
Hydrothermal Carbonization ◽  
Optimal Conditions ◽  
Coffee Husk ◽  
Optimal Value ◽  
Face Centered ◽  
Composite Face ◽  
Temperature Time ◽  
Central Composite ◽  
Water Ratio

The conditions of the hydrothermal carbonization process to produce biochar from coffee husk will be optimized for maximum yield. Besides, response surface methodology (RSM) and central composite face-centered (CCF) method will be used in designing experiments. Also, the optimal value of factors such as temperature, time and biomass: water ratio which can provide a maximum yield of biochar will be worked out using Modde 5.0. As a result, the optimal conditions for maximum yield of biochar was obtained as temperature of 180 oC, 3.5 h and biomass: water ratio of 15 %. It can also be concluded that temperature has greater impact on the transformation of biochar than time and biomass: water ratio.

Liquefaction of almond husk for assessment as feedstock to obtain valuable bio-oils

2019 ◽  
Vol 91 (7) ◽  
pp. 1177-1190
Author(s):  
Maria Margarida Mateus ◽  
Sandro Matos ◽  
Dinis Guerreiro ◽  
Paulo Debiagi ◽  
Daniela Gaspar ◽  
...  
Keyword(s):  
Lignocellulosic Biomass ◽  
Reaction Model ◽  
Effect Of Temperature ◽  
Acid Catalyzed ◽  
Face Centered ◽  
Liquefaction Process ◽  
Favorable Conditions ◽  
Almond Husk ◽  
Composite Face ◽  
Central Composite

Abstract Almond husk liquefaction can be envisaged as an alternative to fossil sources which are becoming exhausted. Lately, the polyols obtain from the lignocellulosic biomass have been under investigation for the production of sustainable chemicals, fuel, materials or other commodities. Within this context, acid-catalyzed liquefaction of such lignocellulosic biomass has been successfully used to access highly functionalized compounds that can be used to replace those produced from petroleum. Almond shells waste can be considered to be part of the lignocellulosic biomass. Its main constituents of are cellulose, hemicellulose, and lignin. In this assay, the biochemical composition of almond husk was estimated based on atomic mass balances, and at the same time, the pyrolysis outcome was also estimated using a kinetic model using some reference compounds. In order to evaluate the use of almond waste as a substrate for acid-catalyzed liquefaction, the most favorable conditions of the liquefaction process were investigated. To better understand the liquefaction process, response surface methodology, in particular, central composite face-centered factorial design was used to set an array of 17 experiments including three replications at the center point leading to the development of a reaction model for further prediction and optimization of the liquefaction outcome. The effect of temperature (120–150 °C), time (20–200 min) and catalyst amount (0.5–5 wt. %) was investigated and a predictive model established.

scholarly journals Forces modeling in a surface peripheral grinding process with the use of various design of experiment (DoE)

Mechanik ◽  
2018 ◽  
Vol 91 (10) ◽  
pp. 929-931 ◽  
Author(s):  
Witold Habrat ◽  
Marcin Żółkoś ◽  
Janusz Świder ◽  
Elżbieta Socha
Keyword(s):  
Standard Deviation ◽  
Coefficient Of Determination ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Box Behnken Design ◽  
Residual Standard Deviation ◽  
Design Expert ◽  
Face Centered ◽  
Result Analysis ◽  
Central Composite

The paper presents forces modeling with the use of DoE models, such as (Box-Wilson) central composite design in face centered variant (CCF) and Box-Behnken design in a surface peripheral grinding process of 100Cr6 steel with M3X60K5VE01-35 grinding wheel. Experiment design and result analysis were done with the use of Design-Expert software. Force models, obtained with application of selected designs of experiment, were compared on the basis of the coefficient of determination, and values of residual standard deviation.

scholarly journals Simultaneous effect of cathode potentials and magnetite concentrations on methanogenesis of acetic acid under different ammonia conditions

2021 ◽  
Vol 27 (6) ◽  
pp. 210317-0
Author(s):  
Arma Yulisa ◽  
Joonyeob Lee ◽  
Sang Hyeok Park ◽  
Seokhwan Hwang
Keyword(s):  
Nitrogen Concentration ◽  
Ammonia Nitrogen ◽  
Total Ammonia ◽  
External Power ◽  
Biodegradation Product ◽  
Face Centered ◽  
The Stability ◽  
Acetate Degradation ◽  
Composite Face ◽  
Central Composite

Electromethanogenesis (EM) is a system that facilitates direct interspecies electron transfer (DIET) in anaerobic digestion (AD) by providing an external power supply to favor desired reactions. Substrates of AD commonly contain ammonia (NH3) as biodegradation product of nitrogen-rich compounds that can deteriorate the stability of AD process. Optimized cathode potential (VCAT) and magnetite (Mag) concentration ([Mag]) are expected to improve AD efficiency in the presence of NH3. Response surface analysis with central composite face-centered design was used in this study to investigate the effect of VCAT and [Mag] under different total ammonia nitrogen concentration ([TAN]). Highest cumulative methane production was achieved at VCAT = -737.4 mV, [Mag] = 18.2 mM, and [TAN] = 1.5 g/L; highest acetate degradation rate was achieved at VCAT = 757.6 mV, [Mag] = 21.4 mM, and [TAN] = 1.5 g/L. The study demonstrated that VCAT promotes either microbial growth or electrochemical NH3 removal. A Shift from acetoclastic to hydrogenotrophic pathway was also observed by the increase of hydrogenotrophic methanogen populations at the end of experiment. This study is beneficial for process control of AD under different NH3 conditions.

scholarly journals Investigation on Fabrication of SS316 Gear by Wire-EDM

2021 ◽  
Vol 346 ◽  
pp. 01044
Author(s):  
Kapil Gupta
Keyword(s):  
Low Cost ◽  
Equal Importance ◽  
Dimensional Deviation ◽  
Cutting Rate ◽  
Predicted Values ◽  
Face Centered ◽  
Traditional Manufacturing ◽  
High Level ◽  
Composite Face ◽  
Central Composite

Manufacturing of miniature gears with good accuracy and quality, and at low cost is a challenging task for traditional manufacturing processes. Wire-cut electric discharge machining (WEDM) has the capacity to machine any conductive material to fabricate typical shaped products like gears with high level of accuracy and quality. In present research, stainless steel (SS) alloy 316 is used to fabricate miniature gears by WEDM. The experimental array is designed according to Response Surface Methodology (RSM) based central composite face centered (CCFC). Four input parameters namely servo feed (SF), duty factor (DF), servo voltage (SV) and wire feed (WF) with three levels each are used for experimental array to investigate the process performance in terms of cutting rate (CR), and product i.e. gear quality in terms of mean roughness depth (Rz) and dimensional deviation (DD). After WEDM parameter optimization, confirmation experiments are performed at the parametric setting by considering equal importance to all response variables. A very close agreement between the experimental and predicted values have been observed.

scholarly journals PENGARUH PENDAPATAN ASURANSI TERHADAP DANA TABARRU� (STUDI PADA PERUSAHAAN ASURANSI JIWA SYARIAH YANG TERDAFTAR DI OJK PERIODE 2011-2018)

2019 ◽  
Vol 5 (2) ◽  
pp. 119
Author(s):  
Muhayati Muhayati ◽  
Budi Sudrajat
Keyword(s):  
Life Insurance ◽  
Quantitative Research ◽  
Degrees Of Freedom ◽  
Linear Regression Analysis ◽  
Insurance Companies ◽  
Coefficient Of Determination ◽  
Insurance Company ◽  
Life Insurance Company ◽  
Significance Level ◽  
Quantitative Research Methods

Insurance income is the amount of money the company receives from the sale of insurance products. Tabarru's fund is a voluntary giving of someone to another person, without compensation, which results in the transfer of ownership of the property from the giver to another person. Aside from premium income, tabaruu funds' also come from investment returns and the accumulation of surfaru underwriting reserves for tabaruu funds' which are redistributed to tabaruu funds'. Based on the background above the formulation of the problem, namely: 1). Is there an Influence between Insurance Income and Tabaruu Funds' on Sharia Life Insurance companies registered with OJK for the period 2011-2018.2). how much influence the Insurance Revenues of the Tabaruu Fund 'on Sharia Life Insurance companies registered in the OJK for the period 2011-2018. This study aims to 1). To find out the effect of insurance income on tabaruu funds' on Sharia Life Insurance companies registered with OJK for the period 2011-2018. 2). To find out how much influence Insurance Income has on Tabaruu Funds' on Sharia Life Insurance companies registered with OJK for the period 2011-2018. This research was conducted at a life insurance company registered with OJK in September to October 2019, with quantitative research methods, testing the hypothesis using simple linear regression analysis through the test (t) with the intent to determine the effect of the independent variables on the dependent variable. It can be concluded, there is a significant effect of the value of t_ (count) of 5.689 while the value of t_ (table) obtained from the distribution table t is sought at the significance of 5%: 2 = 2.5% (two-way test) degrees of freedom (df) nk-1 or 40-1-1 = 38, we get t table of 2.02439. because the value of t_ (count)> t_ (table) = 5.689> 2.02439 with a significance level of 0.005, because the significance value is much smaller than 0.005, it can be concluded that Ho is rejected Ha is accepted. The influence derived from the coefficient of determination (R-Square) of 0.760 means that the magnitude of the effect of insurance income on tabarru funds' 76.0% while the remaining 24.0% is explained by other factors not examined in this study.

scholarly journals Numerical and Experimental Study of the Blade Profile of a Savonius Type Rotor Implementing a Multi-Blade Geometry

2021 ◽  
Vol 11 (22) ◽  
pp. 10580
Author(s):  
Luis A. Gallo ◽  
Edwin L. Chica ◽  
Elkin G. Flórez ◽  
Felipe A. Obando
Keyword(s):  
Power Coefficient ◽  
Ansys Fluent ◽  
Geometric Configurations ◽  
Fluent Software ◽  
Face Centered ◽  
Full Factorial Experimental Design ◽  
Dynamics Models ◽  
Full Factorial ◽  
Central Composite ◽  
Secondary Element

In the present study, the implementation of multi-blade profiles in a Savonius rotor was evaluated in order to increase the pressure in the blade’s intrados and, thus, decrease motion resistance. The geometric proportions of the secondary element were determined, which maximized the rotor’s performance. For this, the response surface methodology was used through a full factorial experimental design and a face-centered central composite design, consisting of three factors, each with three levels. The response variable that was sought to be maximized was the power coefficient (CP), which was obtained through the numerical simulation of the geometric configurations resulting from the different treatments. All geometries were studied under the same parameters and computational fluid dynamics models through the ANSYS Fluent software. The results obtained through both experimental designs showed a difference of only 1.06% in the performance estimates using the regression model and 3.41% when simulating the optimal proportions geometries. The optimized geometry was characterized by a CP of 0.2948, which constitutes an increase of 10.8% in its performance compared to the profile without secondary elements and of 51.2% compared to the conventional semicircular profile. The numerical results were contrasted with experimental data obtained using a wind tunnel, revealing a good degree of fit.

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