The coagulation process is a widely applied technology in water and wastewater treatment.Novel composite polyferric mag-nesium-silicate-sulfate(PFMS)coagulants were synthesized using Na_(2)SiO_(3)·9H_(2)O,Fe_(2)(...The coagulation process is a widely applied technology in water and wastewater treatment.Novel composite polyferric mag-nesium-silicate-sulfate(PFMS)coagulants were synthesized using Na_(2)SiO_(3)·9H_(2)O,Fe_(2)(SO_(4))_(3),and MgSO_(4) as raw materials in this paper.The effects of aging time,Fe:Si:Mg,and OH:M molar ratios(M represents the metal ions)on the coagulation performance of the as-pre-pared PFMS were systematically investigated to obtain optimum coagulants.The results showed that PFMS coagulant exhibited good co-agulation properties in the treatment of simulated humic acid-kaolin surface water and reactive dye wastewater.When the molar ratio was controlled at Fe:Si:Mg=2:2:1 and OH:M=0.32,the obtained PFMS presented excellent stability and a high coagulation efficiency.The removal efficiency of ultraviolet UV254 was 99.81%,and the residual turbidity of the surface water reached 0.56 NTU at a dosage of 30 mg·L^(-1).After standing the coagulant for 120 d in the laboratory,the removal efficiency of UV254 and residual turbidity of the surface wa-ter were 88.12%and 0.68 NTU,respectively,which accord with the surface water treatment requirements.In addition,the coagulation performance in the treatment of reactive dye wastewater was greatly improved by combining the advantages of magnesium and iron salts.Compared with polyferric silicate-sulfate(PFS)and polymagnesium silicate-sulfate(PMS),the PFMS coagulant played a better decolor-ization role within the pH range of 7-13.展开更多
Recent mobile broadband networks require heterogeneous networks supporting high capacity on demand.A hybrid Fiber-Wireless(Fi-Wi)access network integrating Differential Amplitude and Phase Shift Keying(DAPSK)based-Ort...Recent mobile broadband networks require heterogeneous networks supporting high capacity on demand.A hybrid Fiber-Wireless(Fi-Wi)access network integrating Differential Amplitude and Phase Shift Keying(DAPSK)based-Orthogonal Frequency Division Multiple Access(OFDMA)Passive Optical Network(PON)and 4G wireless network using Radio over Fiber(Ro F)technique is proposed.The proposed heterogeneous network is simulated,and the performance is analyzed in terms of Bit Error Rate(BER),Error Vector Magnitude(EVM),Capacity,and Spectral efficiency.The proposed network is simulated considering a higher data rate of 10 and 25 Gbps,and the effect of system parameters like Laser Power,Fiber Length,and Number of users is analyzed.The results show that a higher network capacity of 720 Gbps with an average capacity of about 45 Gbps and a higher spectral efficiency of 4.85 bps/Hz is achieved for the multi-user heterogeneous network link with sixteen users.The minimum value of optical power sufficient to achieve the desired BER is found to be-6 dBm.The suitability of the proposed integrated architecture in supporting multiple services is analyzed by considering different services at each UE.The spectral efficiency of the multi-service link varies from 3 to 4 bps/Hz.展开更多
基金supported by the National Natural Science Foundation of China (No.U1810205).
文摘The coagulation process is a widely applied technology in water and wastewater treatment.Novel composite polyferric mag-nesium-silicate-sulfate(PFMS)coagulants were synthesized using Na_(2)SiO_(3)·9H_(2)O,Fe_(2)(SO_(4))_(3),and MgSO_(4) as raw materials in this paper.The effects of aging time,Fe:Si:Mg,and OH:M molar ratios(M represents the metal ions)on the coagulation performance of the as-pre-pared PFMS were systematically investigated to obtain optimum coagulants.The results showed that PFMS coagulant exhibited good co-agulation properties in the treatment of simulated humic acid-kaolin surface water and reactive dye wastewater.When the molar ratio was controlled at Fe:Si:Mg=2:2:1 and OH:M=0.32,the obtained PFMS presented excellent stability and a high coagulation efficiency.The removal efficiency of ultraviolet UV254 was 99.81%,and the residual turbidity of the surface water reached 0.56 NTU at a dosage of 30 mg·L^(-1).After standing the coagulant for 120 d in the laboratory,the removal efficiency of UV254 and residual turbidity of the surface wa-ter were 88.12%and 0.68 NTU,respectively,which accord with the surface water treatment requirements.In addition,the coagulation performance in the treatment of reactive dye wastewater was greatly improved by combining the advantages of magnesium and iron salts.Compared with polyferric silicate-sulfate(PFS)and polymagnesium silicate-sulfate(PMS),the PFMS coagulant played a better decolor-ization role within the pH range of 7-13.
基金supported by Anna University,Chennai under the Anna Centenary Research Fellowship CFR/ACRF-2020/19244197119/AR1。
文摘Recent mobile broadband networks require heterogeneous networks supporting high capacity on demand.A hybrid Fiber-Wireless(Fi-Wi)access network integrating Differential Amplitude and Phase Shift Keying(DAPSK)based-Orthogonal Frequency Division Multiple Access(OFDMA)Passive Optical Network(PON)and 4G wireless network using Radio over Fiber(Ro F)technique is proposed.The proposed heterogeneous network is simulated,and the performance is analyzed in terms of Bit Error Rate(BER),Error Vector Magnitude(EVM),Capacity,and Spectral efficiency.The proposed network is simulated considering a higher data rate of 10 and 25 Gbps,and the effect of system parameters like Laser Power,Fiber Length,and Number of users is analyzed.The results show that a higher network capacity of 720 Gbps with an average capacity of about 45 Gbps and a higher spectral efficiency of 4.85 bps/Hz is achieved for the multi-user heterogeneous network link with sixteen users.The minimum value of optical power sufficient to achieve the desired BER is found to be-6 dBm.The suitability of the proposed integrated architecture in supporting multiple services is analyzed by considering different services at each UE.The spectral efficiency of the multi-service link varies from 3 to 4 bps/Hz.
