优斯特拉HCU20型变温水箱故障1例

随着心脏外科的发展,许多复杂的心内手术需要较长时间阻断心脏血流,为了缩短停搏时间应用冠状血管灌注法降低心肌温度,以减少心肌缺血性损伤.HCU20型变温水箱就是在手术前对心脏进行降温、术中恒温、术后复温的一种装置.

一种可应用于溴化锂机组制冷的新型钢制合成炉

在氯碱化工企业中,实现水资源的二次利用和副产热能的综合利用将大大降低设备能耗。针对我厂现有工艺,采用新工艺、新技术,改造钢制夹套盐酸合成炉,利用氯化氢反应热,制取热水,作为溴化锂吸收式制冷机的热源,制取7℃的冷冻水。

从石炭二叠纪地层古生物角度探讨欧亚板块和印度板块在青藏高原的界线问题

本文以古生物及地层为依据,指出班公湖-改则-怒江缝合带以北、以东地区,以碳酸盐岩沉积为主,产特提斯型(温水型)动物群、华夏植物群,具有含煤建造,充分显示欧亚板块色彩。该缝合带以南、以西地区,以冰海碎屑岩沉积为主,产冈瓦纳型(冷水型)动物群、舌羊齿植物群,未见含煤建造,具印度板块特征。在此基础上,笔者认为欧亚板块和印度板块的界线应在班公湖-改则-怒江缝合带地区,并进行充分讨论。

Coupled effect of cement hydration and temperature on rheological properties of fresh cemented tailings backfill slurry

The fluidity of fresh cemented tailings backfill（CTB） slurry depends on its rheological properties. Hence, it is crucial to understand the rheology of fresh CTB slurry, which is related to the cement hydration progress and temperature evolution within CTB mixtures. For this reason, a numerical model was developed to predict the evolution of the rheological properties of fresh CTB slurry under the coupled effect of cement hydration and temperature. Experiments were conducted to investigate the rheological behaviours of the fresh CTB slurry. By comparing the simulated results with the experimental ones, the availability of this developed model was validated. Thereafter, the model was used to demonstrate the coupled effect of cement hydration and temperature on the evolution of fresh CTB slurry＇s rheological properties, under various conditions（initial CTB temperature, cement to tailings ratio, and water to cement ratio）. The obtained results are helpful to better understanding the rheology of CTB slurry.

Adsorption Dynamics of Calyx Aroma onto Basic Tea in Scenting Process of Calyx-scented Tea

[Objective] The paper was to study adsorption dynamics of calyx aroma onto basic tea in scenting process of calyx-scented tea, so as to increase aroma and quality of products. [Method] Adsorption experiment was carried out in a hermetic container, and the effect of calyx amount, contact time, moisture content of basic tea and temperature on the scenting process was studied. [Result] The optimal moisture and temperature for scenting process was 4% and 10 ℃, respectively. [Conclusion] The scenting process accorded pseudo-first-order kinetic model, and the adsorption dynamic data of total process could better fit pseudo-second-order kinetic model.

Model for seawater fouling and effects of temperature,flow velocity and surface free energy on seawater fouling

A kinetic model was proposed to predict the seawater fouling process in the seawater heat exchangers.The new model adopted an expression combining depositional and removal behaviors for seawater fouling based on the Kern–Seaton model.The present model parameters include the integrated kinetic rate of deposition(k d)and the integrated kinetic rate of removal(k r),which have clear physical signi ficance.A seawater-fouling monitoring device was established to validate the model.The experimental data were well fitted to the model,and the parameters were obtained in different conditions.SEM and EDX analyses were performed after the experiments,and the results show that the main components of seawater fouling are magnesium hydroxide and aluminum hydroxide.The effects of surface temperature,flow velocity and surface free energy were assessed by the model and the experimental data.The results indicate that the seawater fouling becomes aggravated as the surface temperature increased in a certain range,and the seawater fouling resistance reduced as the flow velocity of seawater increased.Furthermore,the effect of the surface free energy of metals was analyzed,showing that the lower surface free energy mitigates the seawater fouling accumulation.

The standards for skill assessment of operational marine forecast system

To support navigational and environmental applications in coastal waters, marine opera- tional forecast models must be developed and implemented. A forecast model must guarantee that it is scientifically sound and practically robust for performance and must meet or excel all target frequencies or durations before being released to the public. This paper discusses the standard policies and procedures for evaluation of operational marine forecast models. The primary variables to be evaluated are water lev- els, currents and water density (water temperature and salinity).

Hydrological Impacts of Climate Change on Streamflow of Dongliao River Watershed in Jilin Province,China

The impacts of future climate change on streamflow of the Dongliao River Watershed located in Jilin Prov-ince, China have been evaluated quantitatively by using a general circulation model （HadCM3） coupled with the Soil and Water Assessment Tool （SWAT） hydrological model. The model was calibrated and validated against the historical monitored data from 2005 to 2009. The streamflow was estimated by downscaling HadCM3 outputs to the daily mean temperature and precipitation series, derived for three 30-year time slices, 2020s, 2050s and 2080s. Results suggest that daily mean temperature increases with a changing rate of 0.435~C per decade, and precipitation decreases with a changing rate of 0.761 mm per decade. Compared with other seasons, the precipitation in summer shows significant downward trend, while a significant upward trend in autumn. The annual streamflow demonstrates a general down-ward trend with a decreasing rate of 0.405 m^3/s per decade. The streamflow shows significant downward and upward trends in summer and in autumn, respectively. The decreasing rate of streamflow in summer reaches 1.97 m^3/s per decade, which contributes primarily to the decrease of streamflow. The results of this work would be of great benifit to the design of economic and social development planning in the study area.

Intensified East Asian summer monsoon and associated precipitation mode shift under the 1.5 ℃ global warming target

In this study, the East Asian summer climate changes under the 1.5 ℃ global warming （1.5 GW） target in 30 simulations derived from 15 coupled models within the Coupled Model Intercomparison Program phase 5 （CMIP5） are examined. Compared with the current summer climate （1975-2005）, both surface air temperature and precipitation increase significantly over the East Asian continent during the 1.5 GW period （average period 2021-2051）. In northeastern China this is particularly pronounced with regional averaged precipitation increases of more than 7.2%, which is greater than that for the whole East Asian continent （approximately 4.2%）. Due to stronger enhancement of precipitation north of 40°N, the leading empirical orthogonal function （EOF） mode of summer precipitation over the East Asian continent changes from tripolar-like mode to dipole mode. As there is stronger surface warming over the East Asian continent than that over surrounding ocean, the land-sea thermal contrast is enhanced during the 1.5 GW period. As a result, the monsoon circulation in the lower troposphere is significantly strengthened, which causes the increased summer precipitation over the East Asian continent. In addition, larger interannual variabilities of East Asian summer monsoon circulation and associated precipitation are also suggested for the 1.5 GW period.

Prediction and setup of phytoplankton statistical model of Qiandaohu Lake

This research considers the mathematical relationship between concentration of Chla and seven environmental factors, i.e. Lake water temperature (T), Secci-depth (SD), pH, DO, CODMn, Total Nitrogen (TN), Total Phosphorus (TP). Stepwise linear regression of 1997 to 1999 monitoring data at each sampling point of Qiandaohu Lake yielded the multivariate regression models presented in this paper. The concentration of Chla as simulation for the year 2000 by the regression model was similar to the observed value. The suggested mathematical relationship could be used to predict changes in the lakewater environment at any point in time. The results showed that SD, TP and pH were the most significant factors affecting Chla concentration.

ON STRONG SIGNALS OF MONTHLY PRECIPITATION ANOMALIES IN EARLY RAINING SEASON OF GUANGDONG AND CONCEPTUAL MODELS OF PREDICTION

Reanalysis data from NCEP/NCAR are used to systematically study preceding signals of monthly precipitation anomalies in the early raining season of Guangdong province, from the viewpoints of 500-hPa geopotential height field, outgoing longwave radiation (OLR) field, sea surface temperature (SST) and fourteen indexes of general circulation depicting atmosphere activity at high, middle and low latitutes. Being multiple tools of information, a number of conceptual models are formulated that are useful for prediction of the magnitude of monthly precipitation (drought, flood and normal conditionss).

LINKAGE BETWEEN INDIAN OCEAN DIPOLE AND TWO TYPES OF El NI?O AND ITS POSSIBLE MECHANISMS

After compositing three representative ENSO indices,El Nio events have been divided into an eastern pattern(EP) and a central pattern(CP).By using EOF,correlation and composite analysis,the relationship and possible mechanisms between Indian Ocean Dipole(IOD) and two types of El Nio were investigated.IOD events,originating from Indo-Pacific scale air-sea interaction,are composed of two modes,which are associated with EP and CP El Ni o respectively.The IOD mode related to EP El Nio events(named as IOD1) is strongest at the depth of 50 to 150 m along the equatorial Indian Ocean.Besides,it shows a quasi-symmetric distribution,stronger in the south of the Equator.The IOD mode associated with CP El Nio(named as IOD2) has strongest signal in tropical southern Indian Ocean surface.In terms of mechanisms,before EP El Nio peaks,anomalous Walker circulation produces strong anomalous easterlies in equatorial Indian Ocean,resulting in upwelling in the east,decreasing sea temperature there;a couple of anomalous anticyclones(stronger in the south) form off the Equator where warm water accumulates,and thus the IOD1 occurs.When CP El Nio develops,anomalous Walker circulation is weaker and shifts its center to the west,therefore anomalous easterlies in equatorial Indian Ocean is less strong.Besides,the anticyclone south of Sumatra strengthens,and the southerlies east of it bring cold water from higher latitudes and northerlies west of it bring warm water from lower latitudes to the 15° to 25°S zone.Meanwhile,there exists strong divergence in the east and convergence in the west part of tropical southern Indian Ocean,making sea temperature fall and rise separately.Therefore,IOD2 lies farther south.

Indirect heat integration across plants using hot water circles

Total site heat integration(TSHI) provides more opportunities for energy saving in industry clusters. Some design methods including direct integration using process streams and indirect integration using intermediate-fluid circuits, i.e., steam, dowtherms and hot water, have been proposed during last few decades. Indirect heat integration is preferred when the heat sources and sinks are separated in independent plants with rather long distance. This improves energy efficiency by adaption of intermediate fluid circle which acts as a utility provider for plants in a symbiotic network. However, there are some significant factors ignored in conventional TSHI, i.e. the investment of pipeline, cost of pumping and heat loss. These factors simultaneously determine the possibility and performance of heat integration. This work presents a new methodology for indirect heat integration in low temperature range using hot water circuit as intermediate-fluid medium. The new methodology enables the targeting of indirect heat integration across plants considering the factors mentioned earlier. An MINLP model with economic objective is established and solved. The optimization results give the mass flow rate of intermediate-fluid, diameter of pipeline, the temperature of the circuits and the matches of heat exchanger networks(HENS) automatically. Finally, the application of this proposed methodology is illustrated with a case study.

Heat Transfer Analysis of Sterilization of Canned Milk Using Computational Fluid Dynamics Simulations

A uniform and effective heat distribution inside the canned milk is very crucial for achieving effective sterilization. It is extremely difficult to establish the temperature profile inside the canned milk during continuous industrial scale operation. Computational fluid dynamics （CFD） simulation can be a useful tool to determine the temperature distribution of the fluid inside the can during the sterilization process. A CFD model was developed for the sterilization of canned milk at 121 ~C. The simulation results were validated with the experimental measurements of temperatures. The formation and movement of slowest heating zone （SHZ） during the sterilization process was tracked. Moreover, effect of can position （vertical and horizontal） during processing on milk temperature distribution inside the can was also investigated. Higher Grashof and Rayleigh numbers were obtained for vertical positioning of can compared to horizontal can processing. Further, effectiveness of the process was calculated based on F-value and these results reinforced the positive effect of horizontal position of can during the sterilization process.

Precipitation Type Estimation and Validation in China

The results from three methods aimed at improving precipitation type （e.g., rain, sleet, and snow） estimation are presented and compared in this paper. The methods include the threshold air temperature （AT）, threshold wet bulb temperature （WBT） and Koistinen and Saltikoff （KSS） methods. Dot graphs are plotted to acquire the threshold air temperature or the threshold wet bulb temperature using daily averaged air temperature, wet bulb temperature and precipitation data at 643 stations from 1961 to 1979 （precipitation types are not labeled in the database from 1980 to present） in China. The results indicate that the threshold AT or WBT methods are not able to differentiate rain, sleet and snow in the most regions in China; sleet is difficult to differentiate from other precipitation types based on the two threshold methods. Therefore, one threshold AT and WBT method was used in this study to differentiate rain and snow. Based on Gaussian- Kriging interpolation of threshold air temperature （To） and wet bulb temperature （Tw）, the To and Tw contour lines and contour surfaces are calculated for China. Finally, a comparison between the KSS, AT and WBT methods are provided in which the KSS method is calculated based on air temperature and relative humidity. The results suggest that the KSS method is more appropriate for water phase estimation than are the other methods; the maximum precision for rain and snow is 99% and 94%, respectively. The AT method performs better than the WBT method when the critical air temperature is 2℃.

Adsorption Refrigeration Performance of Shaped MIL-101-Water Working Pair

A new metal-organic framework of MIL-101 was synthesized by hydrothermal method and the powder prepared was pressed into a desired shape. The effects of molding on specific surface area and pore structure were investigated using a nitrogen adsorption method. The water adsorption isotherms were obtained by high vacuum gravimetric method, the desorption temperature of water on shaped MIL-101 was measured by thermo gravimetric analyzer, and the adsorption refrigeration performance of shaped MIL-101-water working pair was studied on the simulation device of adsorption refrigeration cycle system. The results indicate that an apparent hysteresis loop ap-pears in the nitrogen adsorption/desorption isotherms when the forming pressure is 10 MPa. The equilibrium ad-sorption capacity of water is up to 0.95 kg·kg^-1 at the forming pressure of 3 MPa （MIL-101-3）. The desorption peak temperature of water on MIL-101-3 is 82℃, which is 7 ℃ lower than that of silica gel, and the desorption temperature is no more than 100 ℃. At the evaporation temperature of 10 ℃, the refrigeration capacity of MIL-101-3-water is 1059 kJ·kg^-1, which is 2.24 times higher than that of silica gel-water working pair. Thus MIL-101-water working pair presents an excellent adsorption refrigeration performance.

Near ground air temperature calculation model based on heat transfer of vertical turbulent and horizontal air flow

In order to calculate the air temperature of the near surface layer in urban environment,the surface layer air was divided into several sections in the vertical direction,and some energy balance equations were developed for each air layer,in which the heat exchange due to vertical turbulence and horizontal air flow was taken into account.Then,the vertical temperature distribution of the surface layer air was obtained through the coupled calculation using the energy balance equations of underlying surfaces and building walls.Moreover,the measured air temperatures in a small area(with a horizontal scale of less than 500 m) and a large area(with a horizontal scale of more than 1 000 m) in Guangzhou in summer were used to validate the proposed model.The calculated results accord well with the measured ones,with a maximum relative error of 4.18%.It is thus concluded that the proposed model is a high-accuracy method to theoretically analyze the urban heat island and the thermal environment.

Impact of Trans-Atlantic-Pacific Ocean Dipole–like pattern on summer precipitation variability over West Africa

Recent findings indicate that rainfall variability over West Africa is characterized by more positive anomalies in the last four decades.The authors demonstrate that the recent interannual rainfall variability is linked to an air–sea phenomenon that occurs in the tropical Atlantic and eastern Pacific Ocean,and then propose the Trans-Atlantic-Pacific Ocean Dipole(TAPOD)index as a measure for this tropical ocean phenomenon,which is found to be closely correlated with the West African summer rainfall anomalies.Using observational and reanalysis datasets,composite analysis suggests that enhanced precipitation in West Africa is associated with the positive phase of the TAPOD,which is characterized by warm sea surface temperature anomalies(SSTAs)in the tropical Atlantic and cool SSTAs in the tropical eastern Pacific Ocean.During the positive phase of the TAPOD,there are significant westerly anomalies over the tropical Atlantic Ocean,which drives anomalous water vapor convergence over West Africa,leading to enhanced precipitation in the region.

Analysis and optimization of heat loss for water-cooled furnace roller

A heat transfer model of furnace roller cooling process was established based on analysis of furnace roller＇s structure. The complicated model was solved with iteration planning algorithm based on Newton search. The model is proved logical and credible by comparing calculated results and measured data. Then, the relationship between water flow velocity, inlet water temperature, furnace temperature and roller cross section temperature, outlet water temperature, water temperature rise, cooling water heat absorption was studied. The conclusions and recommendations are mainly as follows： l） Cooling water temperature rise decreases with the increase of water flow velocity, but it has small relationship with inlet water temperature; 2） In order to get little water scale, inlet water temperature should be controlled below 30 ℃. 3） The cooling water flow velocity should be greater than critical velocity. The critical velocity is 0.07 m/s and water flow velocity should be controlled within 0.4-0.8 m/s. Within this velocity range, water cooling efficiency is high and water temperature rise is little. If cooling water velocity increases again, heat loss will increase, leading to energy wasting.

Isothermal diffusion of water vapor in unsaturated soils based on Fick’s second law

In arid regions, water vapor diffusion predominates the total water migration in unsaturated soil, which significantly influences agriculture and engineering applications. With the aim of revealing the diffusion mechanism of water vapor in unsaturated soil, a water vapor migration test device was developed to conduct the water vapor migration indoor test. The test results demonstrate that the characteristics of water vapor diffusion in unsaturated soil conformed to Fick’s second law. A mathematical model for water vapor diffusion under isothermal conditions in unsaturated soil was established based on Fick’s law. Factors including the initial moisture content gradient, initial moisture content distribution, soil type and temperature that affect the water vapor diffusion coefficient were analyzed. The results show that there was good agreement between the moisture content calculated by the mathematical model and obtained by the indoor experiment. The vapor diffusion coefficient increased with increasing initial moisture content gradient and temperature. When the initial moisture content gradient is constant, the vapor diffusion coefficient increases with the increase of matrix suction ratio in dry and wet soil section. The effect of soil type on the water vapor diffusion coefficient was complex, as both the moisture content and soil particle sizes affected the water vapor diffusion.