scholarly journals Optimizing and evaluating the operational factors affecting the cyanide leaching circuit of the Aghdareh gold processing plant using a CCD model

2015 ◽  
Vol 471 (2184) ◽  
pp. 20150681 ◽  
Author(s):  
Asghar Azizi ◽  
Reza Ghaedrahmati
Keyword(s):  
Particle Size ◽  
Influential Factors ◽  
Coefficient Of Determination ◽  
Processing Plant ◽  
Cyanide Leaching ◽  
Factors Affecting ◽  
Surface Method ◽  
Solids Content ◽  
The Relationship ◽  
Central Composite

A response surface method using a central composite design was employed to evaluate, model and optimize the influence of five main factors in the gold cyanidation process. These factors were pH, solid percentage, NaCN concentration, particle size and leaching time. A second-order equation was proposed and developed for the relationship between the gold recoveries and influential factors. The modelling results indicated that the factors influencing the degree of cyanide leaching of gold were in the order of leaching time > NaCN concentration 2 > particle size > pH > NaCN concentration > leaching time 2 > solid percentage × particle size > solid percentage × NaCN concentration > solid percentage. Also, we obtained a coefficient of determination ( R 2 ) greater than 93%, which showed that the developed model was well fitted to the experimental data. In addition, the model equation was individually optimized by using quadratic programming to maximize gold recoveries within the experimental range. The optimum condition was found to be pH 10.11 for the solution, 36.07% for the solids content, 729.56 ppm for the NaCN concentration, 37.52  μ m for the particle size and 23.2 h for the leaching time. Under these conditions, the highest recovery of gold was achieved of approximately 91.5%.

scholarly journals The effects of age and body weight on powerlifters: An analysis model of powerlifting performance based on machine learning

2019 ◽  
Vol 18 (3) ◽  
pp. 89-99
Author(s):  
Vinh Huy Chau ◽  
Anh Thu Vo ◽  
Ba Tuan Le
Keyword(s):  
Artificial Intelligence ◽  
Machine Learning ◽  
Body Weight ◽  
Root Mean Square Error ◽  
Coefficient Of Determination ◽  
Mean Square ◽  
Analysis Model ◽  
Factors Affecting ◽  
Artificial Intelligence Algorithm ◽  
The Relationship

Abstract As a up and coming sport, powerlifting is gathering more and more attetion. Powerlifters vary in their strength levels and performances at different ages as well as differing in height and weight. Hence the questions arises on how to establish the relationship between age and weight. It is difficult to judge the performance of athletes by artificial expertise, as subjective factors affecting the performance of powerlifters often fail to achieve the desired results. In recent years, artificial intelligence has made groundbreaking strides. Therefore, using artificial intelligence to predict the performance of athletes is among one of many interesting topics in sports competitions. Based on the artificial intelligence algorithm, this research proposes an analysis model of powerlifters’ performance. The results show that the method proposed in this paper can predict the best performance of powerlifters. Coefficient of determination-R2=0.86 and root-mean-square error of prediction-RMSEP=20.98 demonstrate the effectiveness of our method.

scholarly journals Application of Plackett-Burman design for screening of factors affecting pitavastatin nanoparticle formulation development

Folia Medica ◽  
2021 ◽  
Vol 63 (5) ◽  
pp. 775-785
Author(s):  
Vinodkumar D. Ramani ◽  
Girish K. Jani ◽  
Girish U. Sailor
Keyword(s):  
Particle Size ◽  
Influential Factors ◽  
Polydispersity Index ◽  
Formulation Development ◽  
Relative Significance ◽  
Factors Affecting ◽  
Screening Design ◽  
Burman Design ◽  
Nanoparticle Formulation ◽  
Plackett Burman Design

Introduction: Nanoparticle formulation of pitavastatin calcium is a potential alternative to solve the solubility related problem. However, the formulation of nanoparticle involves various parameters that affect product quality. Plackett-Burman design could facilitate an economical experimental plan that focuses on determining the relative significance of many. Aim: The objective of this study was to screen the variables which could significantly affect the pitavastatin nanoparticle formulation. Materials and methods: The pitavastatin nanoparticles were formulated by preparing nanosuspension using the emulsion solvent evaporation technique followed by freeze-drying. A Plackett-Burman screening design methodology was employed in which seven factors at two levels were tested at 12 runs to study the effect of formulation and process variables on particle size and polydispersity index of nanoparticles. The surface morphology and crystalline nature of nanoparticle were also evaluated. Results: The particle size and polydispersity index of nanosuspension was found in the range of 113.1 to 768.5 nm and 0.068 to 0.508, respectively. Statistical analysis of various variables revealed that stabilizer concentration, injection flow rate, and stirring rate were the most influential factors affecting the particle size and polydispersity index of the formulation. X-ray diffraction (XRD) and scanning electron microscopy (SEM) study suggested the amorphous nature of nanoparticles. Conclusions: This study concluded that the Plackett-Burman design was an efficient tool for screening the process and formulation variables affecting the properties of pitavastatin nanoparticles and also for the identification of the most prominent factor.

Effects of calcination variables on quicklime yield of Nkalagu limestone

2021 ◽  
Vol 1 (2) ◽  
pp. 012-023
Author(s):  
Benson Chinweuba Udeh ◽  
Chidinma Lovelyn Ani ◽  
Monday Omotioma
Keyword(s):  
Particle Size ◽  
Mineralogical Composition ◽  
Operating Conditions ◽  
Quadratic Model ◽  
Calcination Process ◽  
Plant Equipment ◽  
The Relationship ◽  
Central Composite

Calcination of Nkalagu limestone for the production of agricultural quicklime is presented. It entails improving the quality of limestone through calcination process. Appropriate scientific instruments/techniques (x-ray diffractometer and scanning electron microscopy) were used for the characterization of the uncalcined and calcined limestone samples. Effects of calcination variables on the quicklime yield were examined. Central composite design of design expert software was used to optimize the calcination process. Analyses of the results revealed that calcite was the major limestone’s mineralogical composition. Quadratic model adequately described the relationship between quicklime yield and calcination factors of temperature, particle size and time. Quadratic model adequately described the relationship between quicklime yield and calcination factors of temperature, particle size and time. The optimum yield of 74.00% was obtained at optima operating conditions; temperature of 937.41 0C, particle size of 85.99µm and time of 3.7 hrs. Characteristics of the quicklime showed that the calcination improved the quality of the sample in terms of mineralogical properties. It is recommended that the generated model should be used to develop chemical plant/equipment for limestone calcination process.

scholarly journals ANALYSIS OF THE RELATIONSHIP BETWEEN BITCOIN AND STOCK INDICES, COMMODITIES AND SECURITIES

2021 ◽  
Author(s):  
Nataliia Kuzminska ◽  
◽  
Mykyta Falko ◽  
Nikita Zaharov ◽  
◽  
...  
Keyword(s):  
South Korea ◽  
The United States ◽  
Influential Factors ◽  
Chinese Economy ◽  
Stock Index ◽  
Coefficient Of Determination ◽  
Stock Indices ◽  
Gold Silver ◽  
The Impact ◽  
The Relationship

The article analyzes the impact of 44 different factors on the change in the price of bitcoin, such as: yields on US one-year bonds, prices for futures on palladium, platinum, gold, silver, copper, Chinese stock indices, German stock index DAX, French index CAC 40, stock indices of South Africa, India, Mauritius, England, Switzerland, Sweden, South Korea, etc. The most influential factors were selected, with the help of which two regression models were built. The presence of insignificant factors in the first model led to the need to consider the second one, which is much better. The second model lacks multicollinearity, but there are autocorrelation of residues and heteroscedasticity. There was an attempt to eliminate autocorrelation of residues, but it led to a significant reduction in the coefficient of determination to 22%. An attempt to explain the causality of the Bitcoin exchange rate to the KOSPRI index has been made. South Korea is a country, which actively cooperates with two main leaders in Bitcoin mining, namely China, where 65 % of new bitcoins are created, and the United States – 23 % of new bitcoins. Modern economic leaders actively influence not only the economy of their country, but also other economies. Korean companies are actively penetrating both the Chinese economy and the US national economy, which determines their impact on Bitcoin mining, as a large amount of necessary electronics is produced by South Korean companies such as SK hynix Inc. As for the palladium futures rate, palladium is a metal which is actively used in production of the electronics needed to mine bitcoin. Prospects for further research depend on trends in the price of bitcoin. It is possible that the price of the cryptocurrency Bitcoin will gradually rise, as some corporations begin to recognize Bitcoin as a means of payment for goods and services. This will increase demand and, as a result, prices. The confidence of large companies in Bitcoin will indicate the reliability of the cryptocurrency, which in turn will give confidence to minority investors in the need to add cryptocurrency to investment portfolios. The rise in prices will indicate the need to study the impact of various factors on changes in the price of Bitcoin. If the popularity of cryptocurrency begins to wane, it will lead to a rapid loss of its price. This development option will indicate the inexpediency of continuing to study the relationship of this cryptocurrency with these factors and the need to find other ones.

scholarly journals The Impact of the Buy Zimbabwe Campaign on Performance of Zimbabwean Companies in the Retail Sector

2017 ◽  
Vol 8 (6(J)) ◽  
pp. 227-236
Author(s):  
Ndlovu N. ◽  
Mafumbate J. ◽  
Mafuka A. ◽  
Brena M
Keyword(s):  
Linear Relationship ◽  
Performance Comparison ◽  
Influential Factors ◽  
Retail Sector ◽  
Company Performance ◽  
Factors Affecting ◽  
Descriptive Research ◽  
The Government ◽  
The Impact ◽  
The Relationship

Abstract: The majority of the Zimbabwean retail companies were in the collapsing mode over the past ten years. This miserable predicament necessitated the government to craft locally-driven remedies, and one of them was the Buy Zimbabwe campaign. This prompted the researcher to assess the impact of the “Buy Zimbabwe” campaign on the performance of the Zimbabwean firms. The study objectives were to establish the impact of “buy Zimbabwe” campaign on demand for local products and factors affecting demand for local products. Furthermore to establish if a company participating in the “buy Zimbabwe” campaign performs better than non-participating firms, earnings per Share was used in the inter-firm performance comparison. The descriptive research design was employed, although the research was both quantitative and qualitative in nature. The classical linear multiple regression analysis was used to establish and explain the relationship between company performances. The results indicated a positive linear relationship between “buy Zimbabwe” campaign and company performance in case of those that adopted Buy Zimbabwe, whereas in case of those that did not adopt Buy Zimbabwe there was a negative linear relationship. The results also discloses that quality and affordability of the product are the most influential factors affect demand for local products and buy Zimbabwe campaign was regarded as the least factor to be considered by consumers. Results from this study point towards the need to put in place supportive policies for the “buy Zimbabwe” campaign to be effective. Keywords: Buy Zimbabwe, retail sector, local products, competitiveness, customer loyalty

scholarly journals Processing of Yandev quicklime for potential amelioration of acidic soil

2021 ◽  
Vol 2 (1) ◽  
pp. 021-029
Author(s):  
Benson Chinweuba Udeh
Keyword(s):  
Particle Size ◽  
Mineralogical Composition ◽  
Batch Process ◽  
Acidic Soil ◽  
Quadratic Model ◽  
Response Analysis ◽  
Slaked Lime ◽  
The Relationship ◽  
Central Composite ◽  
Water Ratio

This study focused on processing of Yandev quicklime for potential amelioration of acidic soil. It involved production of quicklime from the Yandev limestone, characterization and slaking of the quicklime. In a batch process, 10g of the limestone (90mm particle size) was calcined for 3hrs to produce the quicklime. Mineralogical composition of the quicklime was determined by X-ray Diffractometer (XRD), while scanning electron microscope (SEM) was used to examine its surface morphology. The CaO was hydrated for the production of slaked lime (Ca (OH) 2). The slaking process was carried out by digesting CaO in distilled water. During the slaking/hydration process, values of reactivity (rise in temperature) were recorded. Central composite design (CCD) tool of Design Expert Software 11 was used to design the experiment of the slaking process. Quicklime/water ratio, particle size and time were the considered slaking variables, while reactivity was considered as the response. Analysis of the results quicklime is made up of pure calcite with visible pores. Quadratic model adequately described the relationship between reactivity and the considered slaking factors of quicklime/water ratio, particle size and time. Optimum reactivity was obtained as 58.4 0C with the corresponding optimal factors of quicklime/water ratio (0.26 g/ml), particle size (93.0 µm) and time (16.4 minutes). Properties of the slaked lime showed that it is suitable for acidic soil amelioration.

scholarly journals Modeling of tillage operation parameters for draft and power requirement for three tillage implements in a loamy soil

2021 ◽  
Vol 46 (4) ◽  
pp. 10-30
Author(s):  
Paul Okoko ◽  
Emmanuel Ajav
Keyword(s):  
Crop Production ◽  
Coefficient Of Determination ◽  
Basic Operation ◽  
Loamy Soil ◽  
Power Requirement ◽  
Surface Method ◽  
Two Factors ◽  
Tillage Operation ◽  
Model Equations ◽  
Central Composite

Tillage is the basic operation in agriculture and its energy requirements represent a considerable portion of the energy utilized in crop production. The trials were achieved using five tractor speeds (3.6, 5.4, 7.2, 9.0 and 10.8 km/hr) and five tillage depths (10, 15, 20, 25 and 30 cm) to determine implement speed at different tillage depths for 3-bottom disc plough, spring tine cultivator and offset disc harrow on loamy soil. The design of the experiment used were two factors, five levels factorial of Central Composite Rotatable Design of Response Surface Method. Selected models were analyzed using ANOVA at ao. 05 and also validated. The high values of the coefficient of determination for all the selected models and the reasonable agreement between the predicted and actual values of draft and power requirement for all the tested implements show that the generated model equations can be used for predictive purposes for draft and power requirement.

scholarly journals Pretreatment of silk for digital printing: identifying influential factors using fractional factorial experiments

2019 ◽  
Vol 49 (2) ◽  
pp. 145-153
Author(s):  
Saira Faisal ◽  
Aurelio Tronci ◽  
Muhammad Ali ◽  
Long Lin ◽  
Ningtao Mao
Keyword(s):  
Linear Models ◽  
Influential Factors ◽  
Fractional Factorial ◽  
Digital Printing ◽  
Coefficient Of Determination ◽  
Print Quality ◽  
Content Type ◽  
Factors Affecting ◽  
Colour Strength ◽  
Silk Fabrics

Purpose The purpose of this study is to identify the most influential factors affecting the printing properties and print quality of digitally printed silk fabrics in terms of colour strength and fixation percentage. Design/methodology/approach In this study, five factors (concentration of thickener, concentration of urea, concentration of alkali, pH of pretreatment liquor and steaming duration) were investigated using a blocked 25−1 fractional factorial experiment. The type of thickeners [polyacrylic acid and polyacrylamide (PAM)] were considered as a block. Findings Linear models were obtained and statistically tested using both analysis of variance and coefficient of determination (R2), and they were found to be accurate at 90 per cent confidence level. It was revealed that concentration of alkali, concentrations of urea and pH of the pretreatment liquor had an increasing effect on colour strength, whereas concentration of thickener and steaming duration showed decreasing effect on colour strength of digitally printed silk fabrics. Furthermore, concentration of alkali, concentrations of urea had increasing effect on dye fixation percentage, whereas steaming duration showed decreasing effect on dye fixation percentage of digitally printed silk fabrics. In addition, PAM thickener based pretreatment recipe exhibited better printing properties for the digitally printing of silk fabrics. Originality/value The main influences and significant two-factor interactions were discussed in detail to gain a better understanding of the printing properties of digitally printed silk fabrics. The findings of this study are useful for further optimisation of pre- and post-treatment processes for digital printing of silk fabrics.

scholarly journals Active Razor Shell CaO Catalyst Synthesis for Jatropha Methyl Ester Production via Optimized Two-Step Transesterification

2017 ◽  
Vol 2017 ◽  
pp. 1-20 ◽  
Author(s):  
A. N. R. Reddy ◽  
A. A. Saleh ◽  
M. S. Islam ◽  
S. Hamdan
Keyword(s):  
Methyl Ester ◽  
Heterogeneous Catalysts ◽  
Methyl Esters ◽  
High Surface ◽  
High Surface Area ◽  
Coefficient Of Determination ◽  
Catalyst Synthesis ◽  
Surface Method ◽  
Green Technique ◽  
Central Composite

Calcium based catalysts have been studied as promising heterogeneous catalysts for production of methyl esters via transesterification; however a few were explored on catalyst synthesis with high surface area, less particle size, and Ca leaching analysis. In this work, an active Razor shell CaO with crystalline size of 87.2 nm, SBET of 92.63 m2/g, pore diameters of 37.311 nm, and pore volume of 0.613 cc/g was synthesized by a green technique “calcination-hydro aeration-dehydration.” Spectrographic techniques TGA/DTA, FTIR, SEM, XRD, BET&BJH, and PSA were employed for characterization and surface morphology of CaO. Two-step transesterification of Jatropha curcas oil was performed to evaluate CaO catalytic activity. A five-factor-five-level, two-block, half factorial, central composite design based response surface method was employed for experimental analysis and optimization of Jatropha methyl ester (JME) yield. The regression model adequacy ascertained thru coefficient of determination (R2: 95.81%). A JME yield of 98.80% was noted at C (3.10 wt.%), M (54.24 mol./mol.%), T (127.87 min), H (51.31°C), and R (612 rpm). The amount of Ca leached to JME during 1st and 4th reuse cycles was 1.43 ppm ± 0.11 and 4.25 ppm ± 0.21, respectively. Higher leaching of Ca, 6.67 ppm ± 1.09, was found from the 5th reuse cycle due to higher dispersion of Ca2+; consequently JME yield reduces to 76.40%. The JME fuel properties were studied according to biodiesel standards EN 14214 and comply to use as green biodiesel.

Determinant Factors of Student's Perception Toward Educational Loan Repayment

2018 ◽  
Vol 15 (1) ◽  
pp. 73-83
Author(s):  
Siti Zulaika Zolkeplee ◽  
Abu Bakar Hamed ◽  
Ahamad Faosiy Ogunbado
Keyword(s):  
Parental Influence ◽  
Student Loan ◽  
Influential Factors ◽  
Ministry Of Education ◽  
Loan Repayment ◽  
Education Fund ◽  
Relationship Of ◽  
The Relationship ◽  
Universiti Utara Malaysia ◽  
Survey Approach

The issue of unpayable educational loan that lead to student’s defaults has become a worrying trend all over the world. This research aims to examine the relationship of anxiety, parental influence, media awareness, and religiosity on student’s perception on educational loan repayment. A survey approach has been adopted to investigate student’s perception on educational loan repayment in Universiti Utara Malaysia. The data for this study were collected via structured questionnaires which were completed by 359 undergraduate Muslim’s students who acquire their financial loan from National Higher Education Fund Corporation (NHEFC). The data were then quantitatively analyzed using SPSS program. The findings of Pearson’s correlation showed a positive correlation between student’s perception towards educational loan repayment and religiosity, parental influence, media awareness, and anxiety. Further analysis using a multiple regression indicated that all independent variables explained 32.9 per cent of student’s perception on educational loan repayment. The result again indicated that religiosity and parent’s influence are most influential factors on student’s perception towards educational loan repayment. Whilst, media awareness slightly contributed to student’s perception towards educational loan repayment and anxiety gave no impact. The result implied that the Ministry of Education may design the syllabus in school and university curricular by adding the value of responsibility in loan repayment especially in religious and moral subjects. Besides, the Ministry Education of Malaysia are also urged to use media to disseminate the information regarding the importance for students to make loan repayment to parents as well as students. The collection of student loan then can be used for the next generation in financing their study which could result the prosperity of nation.

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