Extended activated sludge model no. 1 (ASM1) for simulating biodegradation process using bacterial technology

Phosphorus is one of the most important nutrients required to support various kinds of biodegradation processes. As this particular nutrient is not included in the activated sludge model no. 1 （ASM1）, this study extended this model in order to determine the fate of phosphorus during the biodegradation processes. When some of the kinetics parameters are modified using observed data from the restoration project of the Xuxi River in Wuxi City, China, from August 25 to 31 in 2009, the extended model shows excellent results. In order to obtain optimum values of coefficients of nitrogen and phosphorus, the mass fraction method was used to ensure that the final results were reasonable and practically relevant. The temporal distribution of the data calculated with the extended ASM1 approximates that of the observed data.

International Conference on Sustainable Rice Production - Policy, Technology and Extension Celebration Activity for International Year of Rice and World Food Day 2004

Rice is the staple food of more than half of the world’s Population.The production,processing and management of paddy rice have provided the basic conditions for the living of mankind.The production of rice has not only created

Relaxed Stable Stability Technology for an Air-to-air Missile

Relaxed Stable Stability （RSS） in an important part of the active control technology. It is a new way to raise the flying speed, distance and maneuverability of missile. Depth study of RSS technology plays an important role for the new concept missile design. This paper describes the detailed definition of RSS and its advantages, pres- ents the research status and prospects for its application in the design of new missiles.

Denitrifying phosphorus removal in a step-feed CAST with alternating anoxic-oxic operational strategy

A bench-scale cyclic activated sludge technology （CAST） was operated to study the biological phosphorus removal performance and a series of batch tests was carried out to demonstrate the accumulation of denitrifying polyphosphate-accumulating organisms （DNPAOs） in CAST system. Under all operating conditions, step-feed CAST with enough carbon sources in influent had the highest nitrogen and phosphorus removal efficiency as well as good sludge settling performance. The average removal rate of COD, NH4^＋-N, PO4^3--P and total nitrogen （TN） was 88.2%, 98.7%, 97.5% and 92.1%, respectively. The average sludge volume index （SVI） was 133 mL/g. The optimum anaerobic/aerobic/anoxic （AOA） conditions for the cultivation of DNPAOs could be achieved by alternating anoxic/oxic operational strategy, thus a significant denitrifying phosphorus removal occurred in step-feed CAST. The denitrification of NO^x--N completed quickly due to step-feed operation and enough carbon sources, which could enhance phosphorus release and further phosphorus uptake capability of the system. Batch tests also proved that polyphosphate-accumulating organisms （PAOs） in the step-feed process had strong denitrifying phosphorus removal capacity. Both nitrate and nitrite could be used as electron acceptors in denitrifying phosphorus removal. Low COD supply with step-feed operation strategy would favor DNPAOs accumulation.

Applying real-time control to enhance the performance of nitrogen removal in CAST system

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.

Low-frequency characteristics extension for vibration sensors

Traditional magneto-electric vibration sensors and servo accelerometers have severe shortcomings when used to measure vibration where low frequency components predominate.A low frequency characteristic extension for velocity vibration sensors is presented in this paper.The passive circuit technology,active compensation technology and the closed- cycle pole compensation technology are used to extend the measurable range and to improve low frequency characteristics of sensors.Thses three types of low frequency velocity vibration sensors have been developed and widely adopted in China.

Preparation and hydration of industrial solid waste-cement blends:A review

Industrial solid waste(ISW)-cement blends have the advantages of low carbon,low energy consumption,and low pollution,but their clinker replacement level in low carbon cement is generally low.To address this challenge,this study considers the latest progress and development trends in the ISW-cement blend research,focusing on the activation of ISWs,the formation of ISW-cement blends,and their associated hydration mechanisms.After the mechanical activation of ISWs,the D50(average size)typically drops below 10μm,and the specific surface area increases above 350 m2/kg.Thermal activation can increase the glassy-phase content and reactivity of ISWs,where the coal gangue activation temperature is usually set at 400-1000°C.Furthermore,the roles of ISWs in the hydration of ISW-cement blends are divided into physical and chemical roles.The physical action of ISWs usually acts in the early stage of the hydration of ISW-cement blends.Subsequently,ISWs participate in the hydration reaction of ISW-cement blends to generate products,such as C-(A)-S-H gels.Moreover,alkali activation affects the hydration kinetics of ISW-cement blends and modifies the proportion of gels.Environmental impacts and costs of ISW-cement blends have also been discussed to guide stakeholders in selecting sustainable ISWs.

Cross section measurements for (n, p) reaction on stannum isotopes at neutron energies from 13.5 to 14.6 MeV

Utilizing the cross sections for 93Nb（n, 2n）93mNb or 27Al（n, a）24Na reactions as monitors, the cross sections for the reactions 115Sn（n, p）115mIn, 116Sn（n, p）116mIn, 117Sn（n, p）117In and 117Sn（n, p）117mIn have been measured at neutron energy ranging from 13.5 to 14.6 MeV through activation technology. Then, the results of present work were compared with the published experimental data.