This study presents morphological and structural variations of K-Feldspar mineral after acid treatment. Both organic and inorganic acids such as C2H2O4, HCl, HNO3 and H2SO4 were employed for this purpose. Another aim ...This study presents morphological and structural variations of K-Feldspar mineral after acid treatment. Both organic and inorganic acids such as C2H2O4, HCl, HNO3 and H2SO4 were employed for this purpose. Another aim of this study was to find an optimum experimental condition for iron(Fe) removal with a minimum damage on the structure of K-Feldspar in which high whiteness index is obtained. The effect of different parameters such as concentration, pH and temperature on the final structure of this mineral was investigated. To find out the chemical composition of powder, XRF was utilized. FTIR, XRD and SEM were employed to study the structure of mineral. Spectrophotometry was chosen to analyze whiteness index of powder after acid treatment. It was found that O—Al—O bond at 647 cm^-1 for H2SO4 and HNO3 treated sample disappeared. However, HCl and C2H2O4 were ineffective at this band. In addition, the results revealed an increase in K-Feldspar content, a decrease in Fe content, an increase in whiteness index and no significant structural change for C2H2O4 leached sample. Whiteness index of 91% was obtained for C2H2O4 leached sample with the pH of 2.5 to 3 at temperature of 50 ℃ and during 1 h.展开更多
The purpose of active distribution networks(ADNs)is to provide effective control approaches for enhancing the operation of distribution networks(DNs)and greater accommodation of distributed generation(DG)sources.With ...The purpose of active distribution networks(ADNs)is to provide effective control approaches for enhancing the operation of distribution networks(DNs)and greater accommodation of distributed generation(DG)sources.With the integration of DG sources into DNs,several operational problems have drawn attention such as overvoltage and power flow alteration issues.These problems can be dealt with by utilizing distribution network reconfiguration(DNR)and soft open points(SOPs).An SOP is a power electronic device capable of accurately controlling active and reactive power flows.Another significant aspect often overlooked is the coordination of protection devices needed to keep the network safe from damage.When implementing DNR and SOPs in real DNs,protection constraints must be considered.This paper presents an ADN reconfiguration approach that includes DG sources,SOPs,and protection devices.This approach selects the ideal configuration,DG output,and SOP placement and control by employing particle swarm optimization(PSO)to minimize power loss while ensuring the correct operation of protection devices under normal and fault conditions.The proposed approach explicitly formulates constraints on network operation,protection coordination,DG size,and SOP size.Finally,the proposed approach is evaluated using the standard IEEE 33-bus and IEEE 69-bus networks to demonstrate the validity.展开更多
文摘This study presents morphological and structural variations of K-Feldspar mineral after acid treatment. Both organic and inorganic acids such as C2H2O4, HCl, HNO3 and H2SO4 were employed for this purpose. Another aim of this study was to find an optimum experimental condition for iron(Fe) removal with a minimum damage on the structure of K-Feldspar in which high whiteness index is obtained. The effect of different parameters such as concentration, pH and temperature on the final structure of this mineral was investigated. To find out the chemical composition of powder, XRF was utilized. FTIR, XRD and SEM were employed to study the structure of mineral. Spectrophotometry was chosen to analyze whiteness index of powder after acid treatment. It was found that O—Al—O bond at 647 cm^-1 for H2SO4 and HNO3 treated sample disappeared. However, HCl and C2H2O4 were ineffective at this band. In addition, the results revealed an increase in K-Feldspar content, a decrease in Fe content, an increase in whiteness index and no significant structural change for C2H2O4 leached sample. Whiteness index of 91% was obtained for C2H2O4 leached sample with the pH of 2.5 to 3 at temperature of 50 ℃ and during 1 h.
文摘The purpose of active distribution networks(ADNs)is to provide effective control approaches for enhancing the operation of distribution networks(DNs)and greater accommodation of distributed generation(DG)sources.With the integration of DG sources into DNs,several operational problems have drawn attention such as overvoltage and power flow alteration issues.These problems can be dealt with by utilizing distribution network reconfiguration(DNR)and soft open points(SOPs).An SOP is a power electronic device capable of accurately controlling active and reactive power flows.Another significant aspect often overlooked is the coordination of protection devices needed to keep the network safe from damage.When implementing DNR and SOPs in real DNs,protection constraints must be considered.This paper presents an ADN reconfiguration approach that includes DG sources,SOPs,and protection devices.This approach selects the ideal configuration,DG output,and SOP placement and control by employing particle swarm optimization(PSO)to minimize power loss while ensuring the correct operation of protection devices under normal and fault conditions.The proposed approach explicitly formulates constraints on network operation,protection coordination,DG size,and SOP size.Finally,the proposed approach is evaluated using the standard IEEE 33-bus and IEEE 69-bus networks to demonstrate the validity.
