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21.
Ultraviolet (UV) disinfection is becoming increasingly popular as an alternative disinfection technology to chlorination in recent years. In this study, we investigated the photoreactivation of Escherichia coli following medium-pressure (MP) UV disinfection of synthetic water by a bench-scale collimated beam apparatus. The UV doses ranged from 1.6 -19.7 mWs/cm2 and photoreactivation was investigated for 6 hours under fluorescent light. In addition, chloramination was applied after UV disinfection to investigate its ability to control photoreactivation. It was found that photoreactivation occurred for all UV doses tested and the increase in bacteria numbers ranged from 0.04 to 1.35 log10. However, the degree of photoreactivation decreased with increased UV doses. Chloramination experiments revealed that the addition of 0.5 mg/l of monochloramine resulted in suppression of photoreactivation for 1 hour only. An increased monochloramine dose of 1 mg/l was found to prevent photoreactivation for the entire duration of the experiment. The results of this study have shown that photoreactivation occurs even after MP UV disinfection, although it is of a lesser extent at higher UV doses. This study has also established that secondary chloramination can effectively suppress and eliminate photoreactivation with a chloramine dose of 1 mg/l. 相似文献
22.
H.A. Barker Author Vitae A.H. Tan Author Vitae K.R. Godfrey Author Vitae 《Automatica》2003,39(1):127-133
Analysis of systems with direction-dependent dynamics is currently limited to cases in which the dynamics in the two directions of the output are first order; results for such systems have been published for both pseudo-random maximum-length binary (MLB) and inverse-repeat maximum-length binary (IR-MLB) inputs. These relatively limited analytical results make it useful to examine alternative ways of modelling such systems and in this paper, Wiener models are considered for this purpose. Methods for optimising the Wiener model parameters by matching the system and model cross-correlation functions, outputs, and discrete Fourier transforms of the outputs are considered, and the results are compared. These methods are also applied to a first-order direction-dependent system with a maximum-length ternary (MLT) input, for which no analytical results are currently available, and to a second-order system with an IR-MLB input. 相似文献
23.
用流动微量量热法研究了十二烷基硫酸钠(SDDS)和十二碳羧酸钠(SL)在克拉玛依油田九区和乌尔禾区油砂上的吸附,简要地计论了吸附机理。所得实验结果表明,SL 在油砂上的吸附强度比 SDDS 的要大,在相当低的浓度下即可迟到饱和吸附。 相似文献
24.
This paper describes the application of an expert system for the evaluation of the short-term thermal rating and temperature rise of overhead conductors. The expert system has been developed using a database and Leonardo expert system shell which is gaining popularity among commercial tools for developing expert system applications. The expert system has been found to compare well when evaluated against site tests. A practical application is given to demonstrate the usefulness of the expert system developed 相似文献
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W.K ChiuS.T Tan 《Computer aided design》2002,34(13):997-1010
In many applications the location of the centre of gravity of a mechanical part is an important factor that a designer must consider. If it is not in a desired location, a part might not work properly, e.g. unbalanced force might be generated in a rotational part. After a part is modeled, its centre of gravity cannot be altered unless its external shape or internal mass distribution is changed. However, the external shape is usually constrained by other design considerations. In this paper, an algorithm is proposed for controlling the centre of gravity of a hollowed part. Using this algorithm, the location of the centre of gravity of a part is controlled by changing its internal mass distribution. 相似文献
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数据压缩的综合字典模型 总被引:2,自引:0,他引:2
谭兆信 《计算机工程与设计》1997,18(1):10-15
文中提出一种无损的数据压缩的字典方法,被称为综合字典方法,该方法在较大程度上消除数据文件中多种形式的冗余,达到较好的压缩效果。 相似文献
30.
Numerous power utilities have installed advanced distributed temperature sensing (DTS) systems to measure the temperature of underground cables. This paper presents a general procedure for real-time assessment of underground cable ratings based on DTS. After the identification and location of hot spots on a cable, the cable installation data, load, and DTS-recorded temperature over a period of time are used to estimate soil thermal parameters and assess cable ratings under normal and overloading conditions. In order to accurately estimate soil thermal parameters, a combined technique of the finite-element method and gradient-based optimization is used. The technique was validated in the laboratory and applied to a rating assessment of a 230-kV/500-MVA cable circuit. The assessed continuous and emergency ratings are helpful in improving the operation of this circuit. 相似文献