Long-term operation optimization of circulating cooling water systems under fouling conditions

Fouling caused by excess metal ions in hard water can negatively impact the performance of the circulating cooling water system(CCWS)by depositing ions on the heat exchanger's surface.Currently,the operation optimization of CCWS often prioritizes short-term flow velocity optimization for minimizing power consumption,without considering fouling.However,low flow velocity promotes fouling.Therefore,it's crucial to balance fouling and energy/water conservation for optimal CCWS long-term operation.This study proposes a mixed-integer nonlinear programming(MINLP)model to achieve this goal.The model considers fouling in the pipeline,dynamic concentration cycle,and variable frequency drive to optimize the synergy between heat transfer,pressure drop,and fouling.By optimizing the concentration cycle of the CCWS,water conservation and fouling control can be achieved.The model can obtain the optimal operating parameters for different operation intervals,including the number of pumps,frequency,and valve local resistance coefficient.Sensitivity experiments on cycle and environmental temperature reveal that as the cycle increases,the marginal benefits of energy/water conservation decrease.In periods with minimal impact on fouling rate,energy/water conservation can be achieved by increasing the cycle while maintaining a low fouling rate.Overall,the proposed model has significant energy/water saving effects and can comprehensively optimize the CCWS through its incorporation of fouling and cycle optimization.

Optimization of circulating cooling water systems based on chance constrained programming

Recent research on deterministic methods for circulating cooling water systems optimization has been well developed. However, the actual operating conditions of the system are mostly variable, so the system obtained under deterministic conditions may not be stable and economical. This paper studies the optimization of circulating cooling water systems under uncertain circumstance. To improve the reliability of the system and reduce the water and energy consumption, the influence of different uncertain parameters is taken into consideration. The chance constrained programming method is used to build a model under uncertain conditions, where the confidence level indicates the degree of constraint violation. Probability distribution functions are used to describe the form of uncertain parameters. The objective is to minimize the total cost and obtain the optimal cooling network configuration simultaneously.An algorithm based on Monte Carlo method is proposed, and GAMS software is used to solve the mixed integer nonlinear programming model. A case is optimized to verify the validity of the model. Compared with the deterministic optimization method, the results show that when considering the different types of uncertain parameters, a system with better economy and reliability can be obtained(total cost can be reduced at least 2%).

Uncertainty Analysis for Ship-Bank Interaction Tests in A Circulating Water Channel

This paper presents a systematic model test program to assess the uncertainty of the ship-bank interaction forces,using the planar motion mechanism(PMM)system in a circulating water channel(CWC).Therefore,the uncertainties due to ship-bank distance and water depth are considered,and they are calculated via the partial differentials of the regression formulae based on the test data.The general part of the uncertainty analysis(UA)is performed according to the ITTC recommended procedure 7.5-02-06.04,while the uncertainty of speed is identified as the bias limit due to the flow velocity maldistribution in the CWC.In each example test for the UA of ship-bank interaction forces,12 repeated measurements were conducted.Results from the UA show that the contribution of water depth error and flow velocity maldistribution to the total uncertainty is noticeable,and the paper explains how they increase with the change of the test conditions.The present study will be useful in understanding the uncertainty regarding the ship-bank interaction force measurement in a CWC.

Exploration on compound water circulation system to solve water resources problems of North China Plain

In order to solve water resources problems in the North China Plain, this paper explored human-nature compound water circulation system from three aspects including urban flood control, surface drainage and saline water in the central and eastern of the North China Plain. Results show that:(1) The technical methods have achieved zero increase in rainwater runoff in urban areas,(2) surface drainage depletion problems can be solved through abandoned water and river water separation method,(3) and technical method through promoting rainwater infiltration would be used to solve problem of saline water in the central and eastern parts. This research provides a new perspective to the ultimate solutions to water resources problems in the North China Plain, and a fresh research direction for the development of hydro-geological science.

Heart of Landscape and Contribution of Building Environment: Discussions about Landscape Construction of Outdoor Environment Water Circulation System

Recently, the increasing concern about the environmental quality of human settlements makes people realize that the attractive environment given by natural ecology also deficiently needs the feedback and protection of nature in some forms so that the natural ecology can be endlessly cycled on its own. Taking the project of German Enterprise Center in Qingdao Sino-German Ecopark as an example, this paper discussed construction of outdoor environment water circulation system using the landscape building method.

Removal of kathon by UV-C activated hydrogen peroxide:Kinetics,mechanisms,and enhanced biodegradability assessment

Kathon(CMI-MI),a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one(CMI)and 2-methyl-4-isothiazolin-3-one(MI),was extensively used in industry as a nonoxidizing biocide or disinfectant.However,it would show adverse effects on aquatic life when it is discharged into surface water.In this study,the removal performance,parameter influence,degradation products and enhancement of subsequent biodegradation of CMI-MI in UV/H_(2)O_(2)system were systematically investigated.The degradation rate of CMI-MI could reach 90%under UV irradiation for 20 min when the dosage of H_(2)O_(2)was 0.3 mmol·L^(–1).The DOC(dissolved organic carbon)mineralization rate of CMI-MI could reach 35%under certain conditions([H_(2)O_(2)]=0.3 mmol·L^(–1),UV irradiation for 40 min).kobs was inversely proportional to the concentration of CMI-MI and proportional to the concentration of H_(2)O_(2).The degradation rate of CMIMI was almost unchanged in the pH range from 4 to 10.Except the presence of CO_(3)^(2-)inhibited the removal rate of CMI-MI,SO_(4)^(2-),Cl^(-),NO_(3)^(-),and NH_(4)^(+) did not interfere with the degradation of CMI-MI in the system.It was found that UV/H_(2)O_(2)system had lower energy consumption and more economic advantage compared with UV/PS system by comparing the EEO(electric energy per order)values under the same conditions.Two main organic products were identified,namely HCOOH and CH_(3)NH_(2).There’s also the formation of Cl^(-)and SO_(4)^(2-).After UV and UV/H_(2)O_(2)photolysis,the biochemical properties of CMI-MI solution were obviously improved,especially the UV/H_(2)O_(2)treatment effect was better,indicating that UV/H_(2)O_(2)technology is expected to combine with biotechnology to remove CMI-MI effectively and environmentally friendly from wastewater.

A STUDY ON FIELD WATER CIRCULATION PATTERN IN THE DRYLAND OF NORTHERN CHINA

Based on the observed data of soil moisture from locating experiments from 1986 to 1990, the pattern of field water circulation in dryland of northern China, where the mean annual precipitation is 300 600 mm, is studied in this paper using the method of water balance. The results show that water satisfying ratio of spring seeding crops is 83.7 90.8 percent and that of winter wheat is about 70 percent in these areas; about 80 90 percent of water consumption of spring seeding crops and about 60 70 percent of water consumption of winter wheat comes from precipitation during the growing period, the rest comes from the soil water storage before the seeding period. But the available soil water is not used thoroughly, about 30 70 percent of available soil water remains unused when the crops are harvested. At the fallow period, the amount of soil water lost by evaporation is very important, which takes up 57 68 percent of precipitation in winter wheat field and 73 244 percent in field of spring seeding crops. Thus restraining soil evaporation, raising the storage ratio of natural precipitation and the soil water utilization efficiency of crops, strengthening the circulation ability of soil water by adopting efficient measures of agricultural techniques, are the main ways for exploiting and developing the potential productivity of natural precipitation in these areas.

On the heat budget and water mass exchange in the Andaman Sea

The characteristics of the T/S structures,water mass exchange and deep circulation in the Andaman Sea are investigated based on the simulation from a high-resolution general circulation model(MITgcm).The results show that,below 1000 m,the water mass is saltier,warmer and more homogeneous in the Andaman Sea than that in the Bay of Bengal,attributing to the strong vertical mixing at the depth of^1800 m.The water mass exchange between the Andaman Sea and the Bay of Bengal goes through three major channels,which manifests itself as follows:the northern channel(Preparis Channel)is the main passage of water mass transport from the Bay of Bengal to the Andaman Sea,whereas the Middle Channel(the south of Andaman Islands and the north of Nicobar Islands)has an opposite transport;the southern channel(Great Channel)features with a four-layer water exchange which results in the least net transport among the three channels;all the transports through the three channels have an intra-annual variation with a period of half a year.At 1000-m depth,the entire Andaman Sea is occupied by a cyclonic circulation in January and July while by an anticyclonic one in April and October.The semiannual cycle found in both the deep circulation and water mass exchange is likely associated with the downwelling eastward-propagating Kelvin waves induced by the semiannual westerly component in the equatorial Indian Ocean during intermonsoon seasons.

Reclamation and reuse of distributed wastewater and programming based on cost analysis

In order to improve the water environment of Songhua River,develop and maintain a healthy water cycle,the article has made theoretical and mathematical analyses of wastewater treatment and reuse.It proposes that the important link of sustainable utilization of urban water resources is wastewater treatment and reuse,and the main approach of sustainable utilization of water resources is water saving,wastewater reclamation and reuse.Through establishing the cost equation of recycle water system and optimizing it by Matlab,an optimal treatment scale of the city recycle distributed wastewater system is obtained.The principles of recycle water system in northern areas are put forward based on the research of sustainable utilization of water resource in Songbei district.The results can provide experiences and references for water saving,wastewater reclamation and reuse in northern cities of China.

Pacific-Indian interocean circulation of the Antarctic Intermediate Water around South Australia

On the basis of the salinity distribution of isopycnal（σ_0=27.2 kg/m^3） surface and in salinity minimum, the Antarctic Intermediate Water（AAIW） around South Australia can be classified into five types corresponding to five regions by using in situ CTD observations. Type 1 is the Tasman AAIW, which has consistent hydrographic properties in the South Coral Sea and the North Tasman Sea. Type 2 is the Southern Ocean（SO） AAIW, parallel to and extending from the Subantarctic Front with the freshest and coldest AAIW in the study area. Type 3 is a transition between Type 1 and Type 2. The AAIW transforms from fresh to saline with the latitude declining（equatorward）. Type 4, the South Australia AAIW, has relatively uniform AAIW properties due to the semienclosed South Australia Basin. Type 5, the Southeast Indian AAIW, progressively becomes more saline through mixing with the subtropical Indian intermediate water from south to north. In addition to the above hydrographic analysis of AAIW, the newest trajectories of Argo（Array for real-time Geostrophic Oceanography） floats were used to constructed the intermediate（1 000 m water depth） current field, which show the major interocean circulation of AAIW in the study area. Finally, a refined schematic of intermediate circulation shows that several currents get together to complete the connection between the Pacific Ocean and the Indian Ocean. They include the South Equatorial Current and the East Australia Current in the Southwest Pacific Ocean, the Tasman Leakage and the Flinders Current in the South Australia Basin, and the extension of Flinders Current in the southeast Indian Ocean.

Gravitational effect of water circulation in the northwest Yunnan

Water circulation is the main disturbance source against precise gravimetry measurement which is one of the principal means of geodynamic study. Some scientists studied the disturbance of water level changes in lakes andrivers and groundwater activities on gravity field.Taking water circulation as a whole and combining it with thehydrogeological conditions in northwest Yunnan mountainous area and the measured gravity data,this paperstudies the features, connections of water circulation in atmosphere,on surface and under ground and its effecton gravimetric data. The main conclusions are as follows: 1) The water circulation in atmosphere has little directdisturbance on gravity field 1 2 ) The change of lake water level may cause gravitational effect of (10- 20) × 10-8m. s-2 ; 3) In the NW Yunnan, types of the groundwater are various,and its changes are complicated, it isnecessary to study point by point. In general, its disturbance on gravity field in this region is about 10 × 10- 8m. s- 2, less than that in plain area.

循环水通道阻塞效应对自主水下航行器水动力系数估算的影响

The Reynolds-averaged Navier–Stokes(RANS)equation was solved using computational fluid dynamics to study the effect of the circulating tank wall on the hydrodynamic coefficient of an autonomous underwater vehicle(AUV).Numerical results were compared with the experimental results in the circulating water tank of Harbin Engineering University.The numerical results of the model with different scale ratios under the same water in the flume were studied to investigate the effect of blockage on the hydrodynamic performance of AUV in the circulating flume model test.The results show that the hydrodynamic coefficient is stable with the scale reduction of the model.The influence of blocking effect on AUV is given by combining theoretical calculation with experiment.

A Lagrangian mean theory on coastal sea circulation with inter-tidal transports I.Fundamentals

A brief review is made on the theory of the Lagrangian residual circulation and inter-tidal transports in a convectively weakly nonlinear system. In the review the emphasis is put on the systematical development of the theory and its weakness of convectively weakly nonlinear approximation. The fundamentals of a Lagrangian tidally-averaged theory on circulation with inter-tidal transport processes have been proposed for a general nonlinear coastal/estuarine system. The Lagrangian residual velocity is strictly de- fined, and it has been verified to be able to embody the velocity field of circulation. A new concept of the concentration for inter- tidal transport processes is presented. The concentration describing the inter-tidal transport processes should be a ＂Lagrangian inter-tidal concentration＂ defined and named, but not the Eulcrian tidally-averaged concentration used traditionally. The circulation described here contains a set of infinite temporal-spatial fields of velocity/concentration, each of which corresponds to a specific value of tidal phases varying continuously over one tidal cycle. When the convectively weakly nonlinear condition（ with a smaller order of eddy diffusion and sources） is approximately satisfied, a set of infinite temporal-spatial fields of velocity/concentration can be reduced to a single one.. the mass transport velocity/the Eulerian tidally averaged concentration as exhibited traditionally.

A bioaugmentation failure caused by phage infection and weak biofilm formation ability

Two biological aerated filters （BAF） were setup for ammonia removal treatment of the circulation water in a marine aquaculture. One of the BAFs was bioaugmented with a heterotrophic nitrifying bacterium, Lutimonas sp. H10, where the ammonia removal was not improved and the massive inoculation was even followed by a nitrification breakdown from day 9 to 18. The nitrification was remained stable in control BAF operated under the same conditions. Fluorescent in situ hybridization （FISH） with rRNA-targeted probes and cultivable method revealed that Lutimonas sp. H10 almost disappeared from the bioaugomented BAF within 3 d, and this was mainly due to the infection of a specific phage as revealed by flask experiment, plaque assay and transmission electron observation. Analyses of 16S rRNA gene libraries showed that bacterial groups from two reactors evolved differently and an overgrowth of protozoa was observed in the bioaugmented BAF. Therefore, phage infection and poor biofilm forming ability of the inoculated strain are the main reasons for bioaugmentation failure. In addition, grazing by protozoa of the bacteria might be the reason for the nitrification breakdown in bioaugmented BAF during day 9-18.

Physical Experiments to Investigate the Effects of Street Bottom Heating and Inflow Turbulence on Urban Street-Canyon Flow

The effects of street bottom heating and inflow turbulence on urbanstreet-canyon flow are experimentally investigated using a circulating water channel. Threeexperiments are carried out for a street canyon with a street aspect ratio of 1. Results from eachexperiment with bottom heating or inflow turbulence are compared with those without bottom heatingand appreciable inflow turbulence. It is demonstrated that street bottom heating or inflowturbulence increases the intensity of the canyon vortex. A possible explanation on how street bottomheating or inflow turbulence intensifies the canyon vortex is given from a fluid dynamicalviewpoint.

A Lagrangian mean theory on coastal sea circulation with inter-tidal transports Ⅱ. Numerical Experiments

The results of the new concept of coastal sea circulation are demonstrated by numerical simulations for the first time.The numerical experiments in three types of rectangular model seas illustrate the dependence of circulation on tidal phases due to the convectively nonlinear effect which is estimated by a newly defined drift dispersion index.Then,the present theory is applied in the Bohai Sea of China.At the Bohai Straits and the Huanghe River mouth area the circulation direction even reverses owing to different initial tidal phases which shows that the theory copes with nonlinearity well.The calculated M2 tide-induced residual circulation shows that a clockwise gyre exists in the center of an anticlockwise gyre in the central Bohai Sea due to the topographic features.In the Bohai Gulf the tide induced circulation shows a 3D structure with outflow at the surface and the inflow at the bottom which can partly explains the spread of the Huanghe River fresh water out of the Bohai Gulf and the inflow of the sediment from the Huanghe River.

A Discussion on the Two-stage Mineralization of the Baguamiao-Shuangwang Gold Orefield, Shaanxi Province, China

The gold orefield studied is located on the south border of the underthrust-collision zone of the Qinling microplate and the North China microplate in the Indosinian epoch. The main ore deposits localized in the area where the WNW-trending compression-shear type fault of the Indosinian epoch intersected the NE-trending tenso-shear type fault of the Yanshanian epoch. The orebody appeared in a chambered or wedged form. The mineral composition is relatively complex. On the southeastern border of the orefield there have developed intermediate-acid anatectic magmatites of the Mesozoic Era. Three-phase inclusions (Lco2, Vco2 and LNaCl-H2O) comprise over 50%, associated with vapor phase consisting of H2O, CO2, CO, CH4, N2 and H2. The ore-forming fluids can be divided into 2 stages (the early and the late). The samples are projected in the area of mixture of initial magmatic and meteoric water on the δD-δ18O diagram, suggesting two types of mineralization, i.e. the re-equilibrated magmatic-hydrothermal type and the circulating geothermal water type of a meteoric water source. The mineralization occurring in this orefield might be a superimposition of 2 tectono-magmatic activities (the Indosinian and Yanshanian movements). Therefore, it is considered a superimposed B-S type gold orefield.

Effect of Danggui Shaoyao San with Huangqi on adriamycin-induced nephrotic syndrome in rats

Objective:To determine the therapeutic effect of Danggui Shaoyao San with Huangqi on rats with nephrotic syndrome(NS)was discussed,and the scientific connotation of TCM treatment principle was elaborated,so as to provide experimental basis for its clinical application.Methods:The NS rat model was established by iv administration of adriamycin;The rats were divided into model group,Danggui Shaoyao San group,Danggui Shaoyao San with Huangqi group,Huangqi group and positive drug group,with 10 rats in control group;The best dosage ratio of Danggui Shaoyao San and Huangqi was screened by Excel;24 h urine protein was measured by BCA method;The electrolyte level was detected by automatic biochemical analyzer;In serum Urea nitrogen(BUN),Creatinine(SCr),Total cholesterol(TC),Triglyceride(TG),Total protein(TP),Albumin(ALB),Immunoglobulin M(Ig-M)and Immunoglobulin G(Ig-G)were detected by the kit;hematoxylin-eosin staining was used to observe the renal morphology;The Total water content(TBW),Extracellular water content(ECF)and Intracellular water content(ICF)were measured by experimental animal body composition analyzer.Results:Compared with the model group,the urine protein in the modified Astragalus group of Danggui Shaoyao Powder was significantly decreased(P<0.01);Urine electrolytes were significantly decreased and serum electrolytes were significantly increased(P<0.01);Serum BUN,SCR,TC and TG were significantly decreased(P<0.01),while TP,ALB,TBW and ICF were significantly increased(P<0.01);The levels of Ig-M and Ig-G were significantly increased(P<0.01),TBW and ICF were significantly increased,and ECF was significantly decreased(P<0.01);Histopathology showed that the pathological changes of renal tissue were obviously alleviated;The improvement of each index was better than that of Danggui Shaoyao San group and Huangqi group.Conclusion:Danggui Shaoyao San with Huangqi group can significantly improve the edema,proteinuria,blood lipid and immune function of NS rats,and the effect is better than that of Danggui Shaoyao San group and Huangqi group.It has the best therapeutic effect on NS,which indicates that Huangqi plays a key synergistic effect on Danggui Shaoyao San,which verifies the scientific connotation of"Yiqi Huoxue Lishui"in the treatment of NS.

Green Charm from Green Design

The way of making people like to use the product by emotional and aesthetic design and making product with charm is illustrated. Examples show that to solve the green charm problem and protect environment only by people＇s responsibility and duty is far from enough. The most important is to attract people loving the green product from the bottom of their heart and to realize the harmonious union of the nature and human beings.