Tag Archives: Mathematical model

Estimating Factors Affecting Investment in the Iraqi Arable Land for the Period 1990-2013 (Published)

The research is focused on the investment in the Iraqi agricultural infrastructure. The problem to be studied in this research is that the agricultural sector in Iraq is strictly suffering from the lower productivity because of the limited investment, especially in the reclamation of more land areas through providing water for irrigation. Data for the period 1990-2014 are used in the analysis. They include the quantities of funds invested in the reclamation of land area, the numbers of hectares reclaimed, the gross domestic product and the annual agricultural production. A mathematical model is formulated by which the economic phenomena is analyzed by means of the method of Ordinary Least Square. GDP and the value of agricultural production were positively proportionate with the quantities of funds allocated to be invested in the reclamation of arable land and conformable to the rules of economic theory. When the value of agricultural production increase by 10%, the funds investment in the reclamation process will increase by 56.8 million dollar. However, there was no influence to the variable of the agricultural area reclaimed on the funds of investment in the reclamation process. It was negatively proportionate with the quantities of funds invested.

Keywords: Investment, Mathematical model, reclamation

Development of a Suitable Mathematical Model for Predicting Yield Strength (Ys) Of Stainless Steel Weld Joints (Published)

A mathematical model for predicting the yield strength (YS) of TIG welded austenitic stainless steel weld joint was developed. The validity and accuracy of the model was confirmed using deviational and statistical analyses as well as scatter diagram. The maximum deviation between the model-predicted YS values and those obtained from actual experiment was less than 6% in absolute terms and the R2 values were above 90%. Furthermore, the scatter diagram showed that the experimental values and the predicted values lie close to the 45o line.

Keywords: Deviational Analysis, Mathematical model, Scatter Diagram., Statistical Analysis, Yield Strength

Development of a Suitable Mathematical Model for Predicting Ultimate Tensile Strength (UTS) Of Stainless Steel Weld Joints (Published)

A mathematical model for predicting the tensile strength (UTS) of TIG welded austenitic stainless steel weld joint was developed. The validity and accuracy of the model was confirmed using deviational and statistical analyses as well as scatter diagram. The maximum deviation between the model-predicted UTS values and those obtained from actual experiment was less than 1.3% and the R2 values were above 90%. Furthermore, the scatter diagram showed that the experimental values and the predicted values lie close to the 45o line.

Keywords: Deviational Analysis, Mathematical model, Scatter Diagram., Statistical Analysis

Development of a Suitable Mathematical Model for Predicting Ultimate Tensile Strength (UTS) of Stainless Steel Weld Joints (Published)

A mathematical model for predicting the tensile strength (UTS) of TIG welded austenitic stainless steel weld joint was developed. The validity and accuracy of the model was confirmed using deviational and statistical analyses as well as scatter diagram. The maximum deviation between the model-predicted UTS values and those obtained from actual experiment was less than 1.3% and the R2 values were above 90%. Furthermore, the scatter diagram showed that the experimental values and the predicted values lie close to the 45o line

Keywords: Deviational Analysis, Mathematical model, Scatter Diagram., Statistical Analysis

MATHEMATICAL MODEL OF HIV/AIDS AT TECHIMAN MUNICIPALITY, GHANA (Published)

The study examined the prevalence of HIV/AIDS in the Techiman Municipality of Ghana. We used model with standard incidence to analyze, model and predict the prevalence of HIV/AIDS in the Techiman Municipality. The model has two equilibrium states: the disease-free equilibrium and the endemic equilibrium states respectively. The stability condition of each equilibrium point is discussed. The basic reproductive number ( ) of HIV/AIDS infection is estimated to be in the Techiman Municipality. Our work shows that the reproductive number of HIV/AIDS infection in the Techiman Municipality is less than 1( ) and therefore concluded that the disease is not epidemic in the municipality as described by the GAC in their study in 2005. We recommend that education on HIV/AIDS in the municipality should be intensified so as to decrease the rate of transmission of HIV in the municipality.

Keywords: Equilibrium points, Mathematical model, Model, Sensitivity Analysis, Stability analysis

MATHEMATICAL MODEL DEVELOPMENT FOR BOD REMOVAL EFFICIENCY IN TANNERY WASTE TREATMENT (Published)

The composite tannery waste water has been treated by anaerobic digestion using varying organic loads. The chromium present has been removed by precipitation method using lime as the agent. The treated water was analysed for pH, influent BOD (So), effluent BOD (Se), mixed liquor volatile suspended solids (MLVSS) before sludge wasting, initial MLVSS and the net growth rate of microorganisms. Results indicated that the BOD and COD removal efficiency decreases with decrease in mean cell residence time c and decrease with increase in F/M ratios. A maximum BOD reduction of 96.9% was obtained at the BOD loading rate of 0.80 kg BOD/m3/day and throughout different loading rates and modified Monod’s equation was used to determine the biokinetic coefficients. A mathematical model was developed to predict the BOD removal efficiency and the model signifies the prediction with a deviation of ±3.6.

Keywords: Biokinetic constants, Mathematical model, Tannery waste