A bench-scale reactor（72 L） red with domestic sewage, was operated more than 3 months with three operation modes： traditional mode, modified mode and real-time control mode, so as to evaluate effects of the operati...A bench-scale reactor（72 L） red with domestic sewage, was operated more than 3 months with three operation modes： traditional mode, modified mode and real-time control mode, so as to evaluate effects of the operation mode on the system performance and to develop a feasible control strategy. Results obtained from fixed-time control study indicate that the variations of the pH and oxidation-reduction potential（ORP） profiles can represent dynamic characteristics of system and the cycle sequences can be controlled and optimized by the control points on the pH and ORP profiles. A control strategy was, therefore, developed and applied to real-time control mode. Compared with traditional mode, the total nitrogen（TN） removal can be increased by approximately 16% in modified mode and a mean TN removal of 92% was achieved in real-time control mode. Moreover, approximately 12.5% aeration energy was saved in real- time control mode. The result of this study shows that the performance of nitrogen removal was enhanced in modified operation mode. Moreover, the real-time control made it possible to optimize process operation and save aeration energy.展开更多
Fog computing is an emerging paradigm that has broad applications including storage, measurement and control. In this paper, we propose a novel real-time notification protocol called RT-Notification for wireless contr...Fog computing is an emerging paradigm that has broad applications including storage, measurement and control. In this paper, we propose a novel real-time notification protocol called RT-Notification for wireless control in fog computing. RT-Notification provides low-latency TDMA communication between an access point in Fog and a large number of portable monitoring devices equipped with sensor and actuator. RT-Notification differentiates two types of controls: urgent downlink actuator-oriented control and normal uplink access & scheduling control. Different from existing protocols, RT-Notification has two salient features:(i) support real-time notification of control frames, while not interrupting ongoing other transmissions, and(ii) support on-demand channel allocation for normal uplink access & scheduling control. RT-Notification can be implemented based on the commercial off-the-shelf 802.11 hardware. Our extensive simulations verify that RT-Notification is very effective in supporting the above two features.展开更多
The principal aim of this paper is to develop an approach to realize stable biological nitrogen removal via nitrite under normal conditions. Validation of the new method was established on laboratory-scale experiments...The principal aim of this paper is to develop an approach to realize stable biological nitrogen removal via nitrite under normal conditions. Validation of the new method was established on laboratory-scale experiments applying the sequencing batch reactor（SBR） activated sludge process to domestic wastewater with low C/N ratio. The addition of sodium chloride（NaCI） to influent was established to achieve nitrite build-up. The high nitrite accumulation, depending on the salinity in influent and the application duration of salt, was obtained in SBRs treating saline wastewater. The maintenance results indicated that the real-time SBRs can maintain stable nitrite accumulation, but conversion from shorter nitrification-denitrification to full nitrification-denitrification was observed after some operation cycles in the other SBR with fixed-time control. The presented method is valuable to offer a solution to realize and to maintain nitrogen removal via nitrite under normal conditions.展开更多
The advantages of OPV （organic photovoltaic） are low cost, little pollution and flexible. But challenge for OPV manufacture still is lacking of accurately performance measurement due to capacitance issue. Firstly, c...The advantages of OPV （organic photovoltaic） are low cost, little pollution and flexible. But challenge for OPV manufacture still is lacking of accurately performance measurement due to capacitance issue. Firstly, characterization of OPV requires considering the slowly temporal response due to capacitance effect, and the relative I-V （current-voltage） curves are strongly dependent on the voltage sweep direction, even for the sweep time only in few seconds or less. Secondly, the IPCE （incident photon-to-electron conversion efficiency） also shows the slowly temporal response due to capacitance effect and is dependent on the wavelength of the incident light. Furthermore, the related features for measuring I-V curves are more sensitive with temperature due to non-linear characteristics issue, but current IPCE spectra of OPV are similar to that happened in conventional crystalline Si or amorphous silicon devices. In this work, we developed a RTOSM （real-time one-sweep method） applied both in I-V and IPCE to analysis different electronic transport materials, and result showed this new approach proposed a good way to slow down testing time and having better accuracy for OPV measurement by eliminating acceptance effect instantly.展开更多
The feasibility of pH and oxidation reduction potential(ORP)as on-line control parameters to advance nitrogen removal in pulsed sequencing batch reactors(SBR)was evaluated.The pulsed SBR,a novel operational mode of SB...The feasibility of pH and oxidation reduction potential(ORP)as on-line control parameters to advance nitrogen removal in pulsed sequencing batch reactors(SBR)was evaluated.The pulsed SBR,a novel operational mode of SBR,was utilized to treat real municipal wastewater accompanied with adding ethanol as external carbon source.It was observed that the bending-point(apex and knee)of pH and ORP profiles can be used to control denitrification process at a low influent C/N ratio while dpH/dt can be used to control the nitrification and denitrification process at a high influent C/N ratio.The experimental results demon-strated that the effluent total nitrogen can be reduced to lower than 2 mg/L,and the average total nitrogen(TN)removal effici ency was higher than 98%by using real-time controll strategy.展开更多
基金The Project of Beijing Science and Technology Committee (No.020620010120) ,the Hi_Tech Research and Development Program(863) of China (No.2004AA601020) ,the Project under Key International Cooperative Programs of NSFC(No.50521140075) and the Project of Key Laboratory of Beiing
文摘A bench-scale reactor（72 L） red with domestic sewage, was operated more than 3 months with three operation modes： traditional mode, modified mode and real-time control mode, so as to evaluate effects of the operation mode on the system performance and to develop a feasible control strategy. Results obtained from fixed-time control study indicate that the variations of the pH and oxidation-reduction potential（ORP） profiles can represent dynamic characteristics of system and the cycle sequences can be controlled and optimized by the control points on the pH and ORP profiles. A control strategy was, therefore, developed and applied to real-time control mode. Compared with traditional mode, the total nitrogen（TN） removal can be increased by approximately 16% in modified mode and a mean TN removal of 92% was achieved in real-time control mode. Moreover, approximately 12.5% aeration energy was saved in real- time control mode. The result of this study shows that the performance of nitrogen removal was enhanced in modified operation mode. Moreover, the real-time control made it possible to optimize process operation and save aeration energy.
基金supported by Macao FDCTMOST grant001/2015/AMJMacao FDCT grants 005/2016/A1, and 056/2017/A2
文摘Fog computing is an emerging paradigm that has broad applications including storage, measurement and control. In this paper, we propose a novel real-time notification protocol called RT-Notification for wireless control in fog computing. RT-Notification provides low-latency TDMA communication between an access point in Fog and a large number of portable monitoring devices equipped with sensor and actuator. RT-Notification differentiates two types of controls: urgent downlink actuator-oriented control and normal uplink access & scheduling control. Different from existing protocols, RT-Notification has two salient features:(i) support real-time notification of control frames, while not interrupting ongoing other transmissions, and(ii) support on-demand channel allocation for normal uplink access & scheduling control. RT-Notification can be implemented based on the commercial off-the-shelf 802.11 hardware. Our extensive simulations verify that RT-Notification is very effective in supporting the above two features.
基金The Hi_Tech Research and Development Program(863) of China(2004AA601020) the National Natural Science Foundation of China(No.50478047)andthe Open Grant of Beijing Key Laboratory
文摘The principal aim of this paper is to develop an approach to realize stable biological nitrogen removal via nitrite under normal conditions. Validation of the new method was established on laboratory-scale experiments applying the sequencing batch reactor（SBR） activated sludge process to domestic wastewater with low C/N ratio. The addition of sodium chloride（NaCI） to influent was established to achieve nitrite build-up. The high nitrite accumulation, depending on the salinity in influent and the application duration of salt, was obtained in SBRs treating saline wastewater. The maintenance results indicated that the real-time SBRs can maintain stable nitrite accumulation, but conversion from shorter nitrification-denitrification to full nitrification-denitrification was observed after some operation cycles in the other SBR with fixed-time control. The presented method is valuable to offer a solution to realize and to maintain nitrogen removal via nitrite under normal conditions.
文摘The advantages of OPV （organic photovoltaic） are low cost, little pollution and flexible. But challenge for OPV manufacture still is lacking of accurately performance measurement due to capacitance issue. Firstly, characterization of OPV requires considering the slowly temporal response due to capacitance effect, and the relative I-V （current-voltage） curves are strongly dependent on the voltage sweep direction, even for the sweep time only in few seconds or less. Secondly, the IPCE （incident photon-to-electron conversion efficiency） also shows the slowly temporal response due to capacitance effect and is dependent on the wavelength of the incident light. Furthermore, the related features for measuring I-V curves are more sensitive with temperature due to non-linear characteristics issue, but current IPCE spectra of OPV are similar to that happened in conventional crystalline Si or amorphous silicon devices. In this work, we developed a RTOSM （real-time one-sweep method） applied both in I-V and IPCE to analysis different electronic transport materials, and result showed this new approach proposed a good way to slow down testing time and having better accuracy for OPV measurement by eliminating acceptance effect instantly.
基金The key international cooperation project was supported by the National Natural Science Foundation of China(Grant No.50521140075)the Project of Beijing Science and Technology Committee(Z0005186040421)the National Key Technologies R&D Program of China(2006BAC19B03)。
文摘The feasibility of pH and oxidation reduction potential(ORP)as on-line control parameters to advance nitrogen removal in pulsed sequencing batch reactors(SBR)was evaluated.The pulsed SBR,a novel operational mode of SBR,was utilized to treat real municipal wastewater accompanied with adding ethanol as external carbon source.It was observed that the bending-point(apex and knee)of pH and ORP profiles can be used to control denitrification process at a low influent C/N ratio while dpH/dt can be used to control the nitrification and denitrification process at a high influent C/N ratio.The experimental results demon-strated that the effluent total nitrogen can be reduced to lower than 2 mg/L,and the average total nitrogen(TN)removal effici ency was higher than 98%by using real-time controll strategy.
