Calculation Method of Hydraulic Characteristics for Direct-Return Chilled Water System

In order to optimize design and operation, it is necessary to calculate accurately hydraulic characteristics large central air-conditioning systems. Simplified Model can not be applied to hydraulic calculation of large pipe network topological structure for its large calculation error. Taking into account the regulating characteristics of terminal branch temperature regulating valve, a direct-return chilled water system is studied, an accurate mathematical model of pipe network hydraulic characteristics has been established and a computer logic algorithm with virtual flow has been given. A direct-return pipe network with ten AHU branches is used as simulation calculation object, the pipe network supply-return water pressure difference is calculated, and also the temperature regulating valve opening and actual flow of each branch are calculated in the condition of different supply-return water pressure difference. The calculated results accord with the natural characteristics of high pressure difference unbalanced for direct-return pipe network. The calculation method can ensure calculation convergence.     

暗管排水对规模农田水稻养分吸收和产量构成的影响

为探究暗管排水对水稻生育后期植株氮、磷、钾养分吸收以及产量构成的影响,以‘南粳46’为试验材料,通过苏州太仓东林农场两块相临的暗管排水田块与传统明沟排水田块进行试验。在暗管排水田距离排水沟和暗管不同的位置采集水稻样品,未铺设暗管的田块取样作对照,分析孕穗期、抽穗期和成熟期水稻植株氮磷钾含量以及产量构成之间的差异。结果表明：随苗沟距的增加,水稻植株氮磷钾养分吸收有减小趋势,靠排水沟越近的区域影响最显著。苗管距2.5 m处植株各器官氮磷钾含量以及产量最高,水稻各器官氮、磷、钾吸收量相对于对照组最高分别可提高25.17%、80.16%和35.19%;产量在苗沟距15 m、苗管距2.5 m处理下达到9.97 t/hm²,大于对照组15.22%,产量差异主要由水稻群体的穗粒数、结实率和千粒重产生。暗管排水可以有效增加稻田氮磷钾养分的吸收和稻田局部增产,但自由暗管排水可能导致暗管正上方表层土壤养分流失而影响水稻植株氮磷钾养分吸收,对于氮磷钾养分吸收规律需后期结合土壤渗漏强度以及渗漏量与土壤养分含量的关系做进一步分析。     

THE OPTIMAL DESIGN AND ENGINEERING APPLICATION OF DISTRIBUTION

This paper introduces the metod of optimal design of municipal water distribution,The main points are the theory,mathematical model,program frame figure and example in practice of the optimal method of hydraulics.The program is applicable to the design and calculation of the pipe network in a city. It gives a simple and convenient calculation method for multiple-scheme design and scheme cmparison of water supply system.     

Study on Application Model of Knowledge Expression

As a key resource, the knowledge management is becoming a research field interested by many researchers. In order to study the mathematics theory base of knowledge expression, in this paper, a knowledge expression model is given. In this model the knowledge system is expressed by multi-tuple, the single knowledge object is expressed by the tuple, a structural expression of knowledge is given using token as example and the application of the model in city water supply pipe network is presented in this paper.     

Load dynamic matching of supply and demand side based on the utilization of urban sewage heat energy

Flowing dynamic characteristics and its temperature dynamic characteristics of a three-level sewage pipe network in Chongqing were analyzed. A mall's building whole year load was simulated. In the adverse condition of wastewater flow, the market construction peak discharge heat was compared with the sewage heat load, the balance between the most adverse flow and the building demand was found. Explored supply and demand matching method between urban sewage and city building load in flow adverse condition to take full advantage of the urban sewage cold and hot resources. the composite system was adeptcd to make up the most unfavorable flow time of sewage average heat load and the construction load difference; it also puts forward principle of load sharing and control strategy aimed at compound system.     

Feasibility for Building the Under-ground Sewage Treatment Plant in Chongqing City

With the development of the economy, the demand forhabitation is enhanced and the sewage and industrial waster water must be disposed before outlet. Today, most of the sewage treatment plants are built on the aboveground without discussing the underground. Therefore, by the comparative analysis of the property and cost of the underground sewage treatment plant and the ground, the underground sewage treatment plant have merits in save the city land and improvement environment.The Chongqing citypossess a lot of advantages in using the space of underground with the analysis of the physiognomy and geology condition of the Chongqing city. Therefore, the development of underground sewage treatment plant is feasible in the Chongqing city.     

GSM技术在棉田水分监测中的应用

利用GSM无线通讯技术实时地采集棉田水分数据,然后将水分监测数据发送到集中监控中心,由上位机决策支持系统进行相应的数据处理,决策结果以GSM短消息方式发送到用户手机上,实现了水分信息的动态管理。     

3D FEM Analysis of Subgrade Soil Movement and Deformation Caused by Extra Shallow Underground Pipe Jacking

Pavement structures will be damaged by subgrade soil movement around the pipes introduced by extra shallow underground pipe jacking. Soil layer deformation with shallow deposits on pipes during extra shallow underground pipe jacking is analyzed using 3D FEM. The effects on pavement deformation created by the friction between shield and soil, injection slurry, jacking forces and the vehicle loads are studied with a practical project. The analytical results show that the ground surface deformation is an uplift first followed by settling with the lower part of the cover moving faster than the upper layers. It is demonstrated by comparing computational results of FEM simulation and the observed data from the in situ test that these FEM models can be applied to real world engineering. Subgrade soil settling on extra shallow underground pipe jacking in a cross section will be stable when the shield has passed through a section with a length twice the diameter of the pipe. Horizontal surface subsidence along the lateral distribution is similar to a normal distribution curve, with the primary affected areas on both sides of the axis approximately 1.5 times the diameter of the pipe.     

A Study Transient on Predictive Calculation Method of on Underground Ventilation Network

The authors developed a computer program of transient predictive calculation method on underground ventilation network. The program approximated a field data set of seasonal cyclic changes of air Temperature and humidity at the inlet to the sine curves, and included sensible heat conduction from rock to air current. The temperature of rock around and airway was calculated by finite difference method. The prediction method can be used to calculate the variation of flow rates, temperatures and humidities of air flow in the airways along underground network.     

Discussion on Direction of Circular Flow of Reversed Return Hot Water System

Aiming at the central mechanical circulated hot water supply system recommended by the current code, the criteria of water flow direction in the pipes of transport and distribution is brought forward based on the hydraulic principle, followed by the analysing with charts of flow directions in the reversed return hot water system consisting of two, three and several vertical pipes in the working conditions of simple return and a little water distributing. There are several directions of circular flow, the only working condition of simple return and single water flow direction which applied in current hydraulic calculation of reversed return hot water supply system is incomplete, certain hydraulic precondition is necessary to ensure circular flow flowing in each vertical pipe as the assumed direction in the course of hydraulic calculation.     

Mathematical Model of Bearing with Bending Moment

Based on the actual situation that there is shortage of water,existence of many dry ditches,over-use of the underground water and the water pollution in the downtown of Jiaozuo city,in this paper,with comprehensive application of the multi-eco technologies such as comprehensive water-handlings and artificial wetland water purifications,the preservative strategies for the surface water and underground water together are put forward to optimize the water cycling,which can on the one hand reduce the contradictories in the water surroundings of the downtown,and on the other hand improve the landscape of dry ditches and sunk areas.     

Effect of new sanitizing formulations on quality of fresh-cut iceberg lettuce

In the present study, three recently patented decontamination agents: peroxyacetic acid combined with lactic acid, and two different combinations of hydrogen peroxide with citric acid (with and without propylene glycol), were compared with sodium hypochlorite and tap water washing regarding their effect on equilibrium modified atmosphere packaged (EMAP) fresh-cut iceberg lettuce. Effects of these sanitizers on respiration rate, electrolyte leakage, microbial levels, and sensory quality of the product after decontamination and during storage (3 d at 4 °C followed by 4 d at 7 °C) were elucidated. Hydrogen peroxide based sanitizers provoked a significant increase in the respiration rate and the electrolyte leakage of fresh-cut iceberg lettuce compared with tap water washing. Peroxyacetic acid combined with lactic acid resulted in similar results to those of tap water washing for all the parameters analyzed. However, other aspects of the combination of peroxyacetic and lactic acids (e.g. efficacy for cross-contamination avoidance) should be assessed in the future in order to determine its suitability for fresh-cut iceberg lettuce processing.     

利用顶空固相微萃取-气相色谱串联质谱法测定养殖水体及水产品中土臭素和二甲基异莰醇的残留量

本文旨在优化微波蒸馏-固相微萃取-气质联用法(Microwave Distillation - Solid Phase Micro extraction-Gas Chromatographic Mass Spectrometry, MD-SPME-GC-MS)测定养殖水体及水产品中土臭素(Geosmin, GSM)和二甲基异莰醇(2-mathylisoborneo1, 2-MIB)的检测方法。主要从微波蒸馏前处理过程的载气流速、微波功率、蒸馏时间和收集方式等4个参数进行了优化,最终确定最佳实验条件：载气流速60 mL/min、微波功率400 W、蒸馏时间6 min并定容于250 mL进行馏分收集定量。在养殖水体检测中,该方法对于GSM和2-MIB的检测限分别达到了1 ng/L和10 ng/L;而在水产品中检测限则分别为 0.025 μg/kg和0.25 μg/kg。该方法的标准曲线在1~200 ng/L和10~200 ng/L的范围内线性关系良好,R²分别为0.9997和0.9982。在水产品样品不同加标浓度(1、5、7、10、20 μg/kg)的回收率实验中,GSM和2-MIB的平均回收率范围分别为45.28%~49.92%、82.15%~87.36%。本实验通过该方法对无锡地区的养殖池塘水样以及水产品进行了检测,发现水样中GSM和2-MIB的浓度均值为分别为19.58 ng/L和58.29 ng/L。而在水产品中,仅检出GSM,其浓度均值为0.61 μg/kg。该方法能够广泛应用于养殖水体以及水产品土腥味物质的检测。     

Experimental and Theoretic Research on Unfree Inundation Water Efflux Flow Field and Circular Field in Rock Salt Well Water-Mining

Simulative experimental research and theoretic analysis on the characteristics of unfree inundation water-flow field and circular field in rock salt well water-mining have been done by glass equipment.The tracer particles spirally circumferentially ascend from bottom to stoma in the triangle vase flow field during the process of unfree inundation efflux flow by positive-cycle pouring water,and the tracer particles fast move up and down in the columnar flow field(jar) as the spouting interval,height of columnar flow field and diameter of the tracer particles are less.While contrary-circular pouring water is done,the water location of centric pipe flow water for the triangle vase is tangential with the down of telescopic pipe and steadily maintains the state.For the columnar flow field,water location is higher than the down of telescopic pipe while the circulation field is just formed and gradually drops until it is tangent with the down of centric pipe.Theory analysis and calculation show that the tracer particles spirally ascend owing to the competition between the up return rate(V_H) and the axial rate(V_m).The fanning orientation of pasting line is the vector sum between V_H and V_m.     

负水头灌溉对温室番茄植株蒸腾规律影响的研究

利用Flow32茎流计分别测定负水头灌溉和常规灌溉方式下的番茄植株蒸腾速率,探讨负水头灌溉方式对番茄植株蒸腾影响及植株蒸腾速率与太阳辐射强度之间的关系,同时分析了负水头灌溉下植株一天不同时刻耗水量差异和负水头灌溉对水分利用效率的影响。试验结果表明,负水头灌溉下的番茄植株蒸腾速率要大于常规漫灌,但有着相同的变化趋势,植株的蒸腾速率主要受太阳辐射强度的影响;负水头灌溉方式能为作物适时适量提供水分,且有效地减少无效地表蒸发和地下深层渗漏,提高了作物的水分利用效率。     

Design and Realization of One Vehicle Management System Based on Web-GIS

This paper presents one of Vehicle Management System base on Web-GIS technology, which has the capability of using all kinds of GPS equipment being made by different company, and aslo can support the customized Vehicle Management System that is constructed for the demand of all kinds of consumer(individual and group).To generate the Web-GIS map, it uses the map generating engine of MapXtreme. To be compatible with different equipments, it uses uniform normalized protocol of communications and the network of GSM. It uses the technology of EJB and B/S for the expansibility. All of these technology build up the expansibility of system and the operating system with Web and reduce the cost of maintenance. The utility of system is aslo enhanced.     

有机肥部分代替无机肥条件下早稻稻田氮素动态变化

为了研究稻田氮素造成面源污染的成因,选出适宜当地水稻种植施肥模式,通过不同种类的农村常用有机肥部分代替无机肥的配比,分析稻田氮素动态变化。结果表明;NH₄⁺-N的损失以地表径流为主,NO₃^--N主要通过渗漏作用造成地下水污染;不合理的有机无机配方肥,也会造成严重的面源污染;不同腐熟程度的有机肥在氮素的损失方式上不同,新鲜猪粪在渗漏作用和地表径流两种氮源损失方面都比较严重,土壤中NO₃^--N平均含量达到13.59 mg/kg,居6个处理最高水平,地表水中全时期NH₄⁺-N总量达到5.65 mg/L,仅低于纯化肥处理。猪粪堆肥地表水中全时期NH₄⁺-N总量达到4.52 mg/L看出,通过地表径流的损失在3种有机肥处理中表现最好,且土壤中NO₃^--N含量平均0.56 mg/kg,因此通过渗漏造成的损失处于6个处理最低水平。沼渣沼液地表水中全时期NH₄⁺-N总量达到4.84 mg/L,土壤中NO₃^--N含量平均为2.87 mg/kg,认为沼渣沼液主要以地表径流的损失方式为主,且通过渗漏造成的氮源损失略低于纯化肥处理。通过实验研究可以发现,猪粪堆肥可作为适宜水稻种植的有机肥。     

Feasibility Analysis of Exploitation "City of Hot Spring" in Chongqing

In Chongqing,the South Hot Spring,Small Hot Spring,and West Hot Spring,do not flow automatically;the flux of North Hot Spring and East Hot Spring Have fallen.The geothermal water did not flow through the geothermal water hole of East Hot Spring.However,the exploitation of "city of hot spring" is plan after 5 year.The paper discusses the hydro-geological conditions,the dynamic hot springs and correlativity among hot springs,analyzes the replenishment conditions and capacity of store water,and the correlativity among the exploitation points of "city of hot spring".It shows that the exploitation of "city of hot spring" is feasible.But in order to exploit "city of hot spring" sustain-ably,the whole yield of "city of hot spring" along with should be planned the every hot spring yield in a geothermal water system of anticline.     

低功耗粮情测控物联网模型研究

以储粮粮情测控为研究背景,以降低粮情测控系统功耗为目标,提出了一种低成本、低功耗、可扩展的弹性粮情测控物联网模型。粮情测控物联网模型包括三层结构:感知层、传输层和汇聚层。感知层支持多参数粮情数据感知;传输层多跳传输粮情数据;汇聚层兼容GPRS、WIFI、WLAN、3G、Enthernet等通信方式,系统结构灵活,扩展性强。实验验证,该模型相较于传统的WSN至少可以延长粮情测控系统的寿命,粮情感知节点在不更换电源情况下可以工作3~5年。     

Analysis on the Diffusion Hazards of Unsteady Leakage of Gas Pipeline

Through analysis on the process of unsteady leakage of gas pipeline,the calculating model of unsteady leakage rate has been established.According to the variable characteristic of unsteady leakage ratio,based on the differential equation of on-flow diffusion,and combining the relevant original and boundary conditions,the diffusion model of unsteady leakage of gas pipeline has been established.Based on the practical application,all of the dangerous areas have been discussed and analyzed.The damaging and destroying areas have been calculated under definite conditions.This will provide safety standards and references for confirming and formulating the safety distance for the important buildings(school etc.) apart from the long high-pressure gas pipeline and main gas pipeline in city.At the same time,this will provide guarantee for reducing the dangerous degree,when accidents happened.