Construction of Risk Assessment Application Model of Epidemic Disease in Large-scale Pig Farms

The application model of epidemic disease assessment technology for Web-based large-scale pig farm was expounded from the identification of epidemic disease risk factors, construction of risk assessment model and development of risk assessment system. The assessed pig farm uploaded the epidemic disease risk data information through on-line answering evaluating questionnaire to get the immediate evaluation report. The model could enhance the risk communication between pig farm veterinarian, manager and veterinary experts to help farm system understand and find disease risk factors, assess and report the potential high risk items of the pig farm in the three systems of engineering epidemic disease prevention technology, biological safety and immune monitoring, and promote the improvement and perfection of epidemic disease prevention and control measures.

Construction and Environmental Protection of Large-scale Livestock and Poultry Farms

Large-scale breeding of livestock and poultry is the main way of modern animal husbandry development.This breeding method is widely used by the majority of owners because of its easy technical promotion,low breeding cost and good economic benefits.But with the development of large-scale livestock and poultry breeding,the pollution and damage to the environment caused by fecal pollution from large-scale livestock and poultry breeding has been criticized by many environmentalists.In this paper,through visit and investigation of large-scale livestock and poultry farms,the methods and measures of environmental protection in the construction of large-scale livestock and poultry farms are proposed.

Operations Improvement Function and Organisational Adaptability of Petroleum Tank Farms in South-South, Nigeria

The study examined the nexus between operations improvement function (dimensioned by contingency planning, benchmarking and continuous improvement processes) and organisational adaptability of Petroleum tank farms in South-South, Nigeria. The contingency theory and the theory of routine dynamics underpinned the study, and positivism was the underlying philosophy. The study adopted the cross-sectional survey through the use of questionnaire. 820 middle and top-level managers constituted the elements of the population, and the Krejcie & Morgan’s formula was used to determine the sample size of 262 respondents. Structural Equation Modeling was deployed to test the hypotheses at a 0.05 significance level. The results showed that contingency planning;benchmarking and continuous improvement processes all have a significant positive relationship with organisational adaptability of Petroleum tank farms in South-South, Nigeria. The study concludes that Petroleum tank farms’ operations should focus on the adoption of contingency planning, benchmarking and continuous improvement processes to enhance organisational adaptability. Therefore, it is recommended that the management of Petroleum tank farms should put in place mechanisms to advance continuous improvement processes by allocating the necessary amount of resources, such as energy, time and money, in order to promote the continuous development of the continuous improvement systems. Furthermore, managers of Petroleum tank farms should make better the adoption of contingency planning, ensuring that there is as much necessary training and information for employees on how to act during a crises situation, in order to evaluate safety and prepare in advance for recovery from disasters.

LNG罐区安全联锁系统的应用设计

LNG罐区作为存储原料和成品的重要区域,其安全运行对于整个生产过程具有至关重要的意义。通过对LNG罐区潜在风险的分析,结合安全联锁系统的原理和功能。文章基于国产安全联锁控制器,提出了一套完整的安全联锁应用设计方案,包括系统原理、系统结构、仪表和执行机构选型、软件设计,同时从冗余、预防、监测3个方面提出了安全策略,旨在提高LNG罐区的安全性和可靠性。

Circulation-Enhanced Tank Heating Using Shallow Profile Coil Bundles

Heavy fuel oils require heated tanks to facilitate their transportation and processing.This paper proposes and investigates threeand four-level heating coil bundles.Numerical study revealed that powerful large-scale circulation of the heated fluid enhances heat transfer,delivering 16.7%and 23%improvements to the average heat transfer coefficient for the three-and four-level bundles,respectively.Furthermore,this circulation improves oil mixing and limits the variation in bulk oil temperature to-0.3 to+1.3°C from the average.The study also quantified oil flow velocity near the bottom of the tank.The time-averaged horizontal components of velocity,estimated 25 mm and 50 mm above the bottom of the tank,exceed 2 mm/s and 4 mm/s,respectively.The proposed heating coil bundles feature a compact design that reduces the material and labor costs of construction and that,by occupying only a small portion of the bottom of the tank,improves accessibility,maintenance,and cleaning.

Bio-Filtration Technologies for Filtering Ammonia in Fish Tank Effluent for Reuse--A Review

Peri-urban fish farms with limited access to open natural water bodies draw fresh water from urban water supply and dug wells,which is unreliable and costly.Reuse of fish pond effluent is also limited by high ammonia concentration(>0.3 mg/L)that renders water toxic and is stressful to fish.Despite the existence of several fish effluent treatment methods,not all may be appropriate for a particular location.This review article therefore examines the various fish effluent treatment methods to aid selection of the most suitable one(s)for peri-urban areas.The key parameters considered in their comparison were:initial,operational and maintenance costs;ammonia removal efficiency;energy consumption and land requirement.The effluent treatment methods are both conventional and non-conventional.Despite a slight higher treatment efficiency and less space requirement by conventional methods,they mainly require reliable power supply for continuous running,highly skilled labor for operation and maintenance leading to high operational costs.In addition,their investment costs are higher than non-conventional methods,hence not widely applied in developing countries and majority have broken down.On the other hand,non-conventional methods such as constructed wetlands are widely in use for treating effluent mainly due to their cost effectiveness and no or little energy requirement.Constructed wetlands were found most suitable bio-filtration system for treating fish effluent because they are cost effective,require less skilled labor and still have better effluent treatment though space required is slightly more.Vegetables(lettuce,collards,etc.)have potential to grow in constructed wetlands thus form vegetable-based bio-filtration units which serve not only as bio-filters but also provide additional sources of nutrition and income.This review indicated limited information on the appropriate size and performance of vegetable-based bio-filtration unit utilizing indigenous vegetables and recommended further research to explore the idea.

基于“船载舱养”模式国内养殖工船的大气和水污染排放控制研究

基于“船载舱养”的养殖工船模式构建理念,结合10万吨级大型养殖工船建造项目,阐述目前法规、国标对养殖工船防止大气污染和防止水污染的控制措施,并对养殖工船设计、建造和营运给出建议。

油罐区电缆槽盒耐火性能测试方法研究

为提升油罐区电缆槽盒耐火性能测试的准确性和效率,提出一种以绝缘电阻作为判定指标的电缆槽盒耐火性能快速测试方法,并以试验的方式验证该方法的有效性和电缆槽盒的耐火性能。结果表明:测量电缆绝缘电阻值可以准确反映电缆槽盒在火灾时的失效过程,以107Ω作为电缆绝缘电阻失效判定指标可以准确反映电缆槽盒的耐火极限。

基于粒子群算法参数自我调整的罐区液位自动化控制方法设计

由于采集的罐区液位信号存在大量的干扰信号,导致控制器输出的操作量不准确,从而使得液位控制值与目标值的偏差较大,控制精度偏低。为此,提出基于粒子群算法参数自我调整的罐区液位自动化控制。依据罐区的结构特点与液位控制目标,求取液位变化率与液位二阶加时滞函数,进而设计罐区模型结构,结合预设的控制逻辑和液位传感器提供的实时数据构造液位自动化控制器,并通过对罐区液位输入信号进行采样和滤波,以剔除干扰信号,由此计算输出操作量,基于此,引入粒子群算法参数自我调整方法对控制器的参数进行自适应整定,从而优化控制器参量,实现罐区液位的控制。实验结果表明,利用所提方法对罐区液位进行控制后,输出的控制值与目标值基本相符,控制精度较高。

基于PPRR理论的化工罐区定量应急管理能力研究

化工储罐区是危险源数量极多的场所,通过传统的应急管理方法无法量化并表征储罐区的动态风险。因此,基于PPRR理论构建了化工罐区火灾应急管理能力定量评价模型;利用区间层次分析法确定了评估指标的权重,使用改进的模糊综合评价法,对化工罐区火灾应急管理能力进行了定量评价;运用基于PPRR理论的化工罐区火灾应急管理能力定量评价模型,对M石化公司化工罐区火灾应急管理能力进行评价,并对此模型的准确性进行了验证。结果表明,M石化公司化工罐区火灾应急管理能力的评价得分为3.35,与定性评价结果相吻合,验证了此模型的准确性;该模型能很好地解决指标重要程度不确定的问题,而改进的模糊综合评价法能指出化工罐区的欠缺之处及欠缺程度,可为完善和提高化工罐区火灾应急管理能力提供新思路。

养殖工船养殖舱清洁系统的设计与清洁能力分析

为解决养殖工船养殖舱壁固体废料附着堆积、人工清洁效率低、不能及时清理等问题,设计了一种适用于养殖工船养殖舱的清洁系统。该清洁系统结合养殖舱的养殖特点,设计有清洁装置、绕行装置、传动装置以及排污装置。通过仿真试验分析,得到系统合适的运行速度以及清洁装置不同工况下的清洁效率。结果显示,系统的运行速度应该控制在0.5 m/s以内,运行速度越慢,系统的清洁效率越高,提高毛刷的转速能够有效提高清洁效率。毛刷在单位路径下的工作圈数与清洁效率正相关,当运行速度为0.2 m/s、转速为190 r/min时,清洁效果比较理想。清污刮板为30°时,可有效清除残留附着物。研究表明,该清洁系统可解决养殖舱在养殖过程中的清洁问题,且结构紧凑有效,具有较高的工作效率和性价比,有较好的推广价值。

基于“船载舱养”模式大型养殖工船制氧系统的设计和应用

基于“船载舱养”的养殖工船模式,结合10万吨级大型养殖工船项目的设计建造过程,研究分析养殖工船制氧系统的设计和应用现状和要点。分析结果表明,虽然制氧技术方面已经较为成熟,但是养殖工船上的制氧系统的设计和应用缺乏船上使用的标准和规范,目前只能参考陆地行业的相关标准,其应用环境和安全条件具有差异性。希望本研究能够引起学者与政策制定者的关注,促进该制氧系统在船舶领域的规范和标准化进程,从而为深海养殖制氧技术的深入研究提供指引。

烟台市海洋牧场网箱养殖发展现状与对策

为研究海洋牧场网箱养殖发展现状,以烟台市海洋牧场为例,对其网箱养殖进行调研,归纳总结出烟台市海洋牧场网箱养殖发展情况。研究发现,烟台市海洋牧场网箱养殖存在缺乏养殖品种、养殖配套装备技术有待进一步发展完善、深水网箱养殖产业链不完善、政府支持力度不够及金融支撑体系有待健全等问题,提出重视海水养殖品种开发、重视养殖配套装备技术研发推广、贯彻三产融合理念、延伸产业链条、坚持规模化集约化发展、加大政策扶持力度及健全深水网箱养殖金融支撑体系等对策建议。

基于蝴蝶结-贝叶斯网络的站场储罐动态风险评价

为实现站场储罐区风险的实时评估和事故预防,在建立蝴蝶结模型的基础上,通过映射规则引入时间维度,归纳了储罐泄漏的主要危险源和不同安全屏障下的事故后果类型,通过遗漏概率模型确定了不同节点的条件概率,以此形成站场储罐的动态贝叶斯网络模型,推理出储罐事故发生概率随时间的变化规律,并进行实例分析和验证。结果表明:储罐泄漏概率先增大后减小,并在第3个时间片处达到峰值;后验概率较大的基本事件均与储罐腐蚀的中间事件相关,随着时间片的延长,严重腐蚀等级呈线性上升,中等腐蚀等级基本保持不变,轻微腐蚀等级呈指数下降;在第10个时间片上,油气聚集的事故后果发生概率最大,蒸气云爆炸的事故后果发生概率最小,说明强化紧急停车系统和避免形成受限空间是减轻事故后果的有效途径。

What are the Determinants of Large-scale Farming in China？

The Chinese Government has increased its focus on expanding farm scale to promote agricultural development since 2010. A series of favorable polices has been adopted to support large-scale farming. Using a multivariate probit model and 2015 and 2016 rural household survey data, the present paper examines the factors that influence small farmers＂ decision to become large-scale farmers. The empirical regression results suggest that the decision to become a large-scale farmer is significantly influenced by household human capital cooperative membership, marketing channels, land-transfer contracts and government policies. However, the influence of these factors differs with respect to becoming large-scale grain and non-grain farmers. These results imply that policy tools should target these factors and the appropriate group of small-scale farmers. Generally, both central and local governments should promote large-scale farming by enhancing rural households＇ human capital improving marketing channels and providing agricultural social services, as well as encouraging returning migrant workers to engage in large-scale farming,

化工企业罐区水体污染事故预防与控制

化工企业可燃液体罐区的排水系统应依据罐区排水系统设计规范(标准)中相关规定进行设计。罐区排水系统作为化工企业水体污染事故预防与控制体系的一部分,若设置不当可能引起局部环境污染或安全隐患,应引起设计和管理足够的重视。文章通过设计实践总结了设计要点:罐区排水系统实施清污分流,防火堤外设置阀门井,必要时设置水封井,正常情况下非排水时,阀门处于关闭状态。

基于FDS的甲醇罐区池火灾事故后果模拟研究

大容量的甲醇罐区在化工生产项目中往往以危险化学品重大危险源的形式存在,是防灭火的重点目标。为了有效选取最佳灭火位置、科学应急处置,通过池火灾模型分析与计算,确定在常年风向一定时,无风、平均风速、中等风速和最大风速四种情况下甲醇储罐区池火灾热辐射强度和范围。文章以徐州某化工厂甲醇罐区为例,利用FDS软件构建火灾模型,分析不同热辐射强度对周围设施的破坏情况,完成热辐射演化三维仿真效果,为最佳灭火位置设置提供建议。

LARGE-SCALE FARMING BENEFITS SOIL ACIDIFICATION ALLEVIATION THROUGH IMPROVED FIELD MANAGEMENT IN BANANA PLANTATIONS

Large-scale farming by agricultural land transfers has been increasingly promoted in recent years,but the possible impacts on crop production,especially cash crops,and soil acidification remain unclear.This study obtained data for 110 banana plantations in Long’an County,China,and categorized them into small(<0.67 ha),medium(0.67−6.7 ha),and large(>6.7 ha)to determine banana cultivation,nutrient management,and soil acidification rates on farms of the three sizes.Banana yield per unit area significantly increased with increased farm size,and large farms had the highest average yield(48.9 t·ha^(−1))with the least variation.Despite a significant increase in organic fertilizer and base cation inputs,nitrogen(N)surplus did not differ significantly with increasing farm size.With large farms,actual soil acidification rate was significantly lower by 19.1 to 24.0 keq·ha^(−1)·yr^(−1);however,potential soil acidification rate increased with increased overuse of phosphorus.Overall,larger banana plantations used fewer mineral N fertilizers reducing the rate of soil acidification and increasing the H+buffering provided by organic fertilizers.It is concluded that larger farms deliver the dual benefits of higher,less variable banana yield and mitigation of soil acidification by substituting organic N for mineral N fertilizers,supporting sustainable soil management and food production.

石化储罐区紧急切断阀执行器的防火保护研究进展

为提升石化储罐区内紧急切断阀执行器在火灾中的安全性能,从石化行业对储罐区火灾安全的要求出发,对目前国内外紧急切断阀执行器的防火保护设备及应用现状进行总结,并对现有的常见实体火灾实验方法和石油化工环境下的防火罩火灾试验进行梳理。研究发现:不同紧急切断阀执行器的防火设备存在防火性能的测试方法与评判标准不统一的问题。根据目前我国石化行业的防火需求提出典型防火罩的防火性能判定指标,制定紧急切断阀执行器防火性能测试方法标准,以实现对防火罩防火性能的规范管理。

基于动态贝叶斯网络的储罐区多米诺效应事故研究

化工储罐区存放的多为易燃、易爆的危险化学品,若储存不当发生泄漏,极易引发多米诺效应,造成财产损失甚至是更为灾难性的后果。选取某化工企业储罐区,分析多米诺效应事故扩展过程中的关键时间节点,运用Probit模型和贝叶斯方法计算储罐多米诺效应扩展概率;利用动态贝叶斯网络方法和GeNie软件,确定储罐区多米诺效应事故的动态演变过程。结果表明:T2、T3、T4、T5、T6、T7、T8储罐在0~10 min、>10~13 min、>13~18 min、>18~23 min和>23 min 5个时间段内多米诺事故扩展概率分别为0.930、0.930、0.607、0.526、0.517、0.597、0.584。该结果为后续化工储罐区风险评估提供理论依据,并为多米诺效应事故应急决策提供一定的参考。