鱼类循环水养殖中的水质参数自动控制

鱼类循环水养殖是一种工业化的养殖方式,其主要特征是养殖水体的循环利用,这一过程要对养殖水体进行处理,对水质参数进行监测与控制,要涉及物理、化学、生物及控制理论等许多学科的理论与技术。本文列出了循环水养殖水体中影响鱼类生长的各种因子并总结了前人的研究成果,进而提出了一些水质参数的控制方式。其中着重分析了溶解氧、pH值和氨氮的监测与控制方式,为进一步实验研究奠定基础。     

船舶改建焊接变形的控制与矫正分析

从影响船舶焊接变形的因素、船舶改建施工前准备、施工过程控制和发生变形后处理几个部分进行分析探讨,提出改建过程中船舶焊接变形的控制措施,包括采用合理的焊接顺序和方法、选择正确的焊接工艺参数和采取合理的控制焊接变形的方法,并对船舶改建焊接变形给出常用矫正手段.     

小河流水环境容量测算与容量总量控制

实施水污染物总量控制是改善水环境质量的重要措施，我国对水污染物排放总量控制先后经历了浓度控制和目标总量控制阶段，现已逐渐进入容量总量控制阶段。浓度控制和目标总量控制制度的实施，在特定的历史条件下，在环境管理工作中发挥了巨大的作用。但随着我国环境管理方式和经济发展模式的改变，原有的浓度控制和目标总量控制制度已不能适应。为此，探索、建立容量总量控制机制是当前环保工作中的一个重要课题。本文是作者在导师的指导帮助下针对蚂蚁河流域水质现状，进行了水质达标分析，对辖区内的点源、面源和生活源排放情况进行了调查分析，选择适宜的容量测算模型，并科学地确定了COD、氨氮等水主要污染物的降解系数等计算参数，对该河水主要污染物环境容量进行了计算与核定，指出污染物的水环境容量研究是进行流域排污总量控制的基础，并对环境容量管理工作提出了建议。     

基于ARM9及Android的水产养殖监控系统设计

为促进水产养殖的技术更新,提高生产过程的自动化水平,设计了一种基于ARM9处理器和Android操作系统的水产养殖自动监测控制系统。采用STM32微处理器实时采集养殖场水温、p H、溶氧、水位4项参数,用ZigBee节点技术进行综合,并以无线方式传输数据至Android终端,实现水质参数的自动调节与控制。当溶氧浓度和水位超出预定阈值时,系统根据检测结果自动控制增氧机与补排水泵的开启与关闭;当p H与水温超出阈值时,系统会通过终端及现场报警提醒人工干预,减少环境对水产养殖产量的影响。测试结果显示,可控制溶氧、水位在合理误差范围内(分别为±0.4 mg/L、±2 cm),可以满足水产养殖远程监控的要求。     

浅析完善企业采购业务内部控制制度

内部控制对保证企业经济活动有效进行起着十分重要的作用,一个合理完善的采购内部控制制度的落实已成为实现企业降低成本、保证企业利益最大化的重要条件。文章从分析采购业务内部控制制度的目标入手,强调了采购业务内部控制制度的原则并对制度的流程进行了设计,对完善企业采购业务内部控制制度提出了新的看法。     

罗非鱼养殖质量安全控制技术

罗非鱼养殖质量控制参照HACCP的原则。对全养殖过程所有影响成鱼质量安全的潜在危害进行分析，对每个潜在危害发生的可能性及其严重程度进行评价，找出影响罗非鱼质量安全的具有风险性和严重性的显著危害，确定养殖过程质量监控关键控制点，制定显著危害的预防措施和关键控制点的关键限值。建立对关键控制点监控的系统，制定纠偏措施，建立验证程序和记录档案。建立起罗非鱼养殖质量安全控制体系进行质量控制．确保影响罗非鱼质量安全的所有危害得到监控．产出的罗非鱼完全符合无公害水产品和加工出口原料要求。     

浅析民营企业的成本控制

民营企业是我国社会主义市场经济的重要组成部分,其成本控制是管理工作的长期课题,如何更合理、更科学地进行成本控制,文章从成本管理与控制的重要性即增强成本观念、实行全员成本管理,注重成本效益观,扩大成本控制范围,加强成本信息管理和内部控制制度,提高信息反应能力和加强信誉成本控制五个方面进行了阐述。     

质量控制图在水产饲料氨基酸分析中的应用

通过对实验室自制标准物料-豆粕样品中氨基酸含量的多次测定,建立X-S质量控制图,开展水产饲料氨基酸分析日常质量控制。试验按照GB/T 18246-2000,通过微波水解-离子交换-柱后衍生-紫外检测法对豆粕样品氨基酸含量进行连续测定,并以FAPAS奶粉标准物质验证,利用偏度-峰度检验法对离群值进行判断,建立赖氨酸、甘氨酸、氨基酸总量质量控制图。结果显示,质量控制图中豆粕质控样赖氨酸、甘氨酸、氨基酸总量测定的RSD值均小于4%,FAPAS奶粉标准物质测定值落在参考范围内,建立的质量控制图能对日常氨基酸检测结果进行有效监控。结果表明,所建立氨基酸质量控制图直观有效,能对过程存在的异常因素起到预警作用,并可节约成本。     

HACCP体系在鲑鳟鱼池塘养殖中的应用

HACCP体系是对可能发生在食品生产环节中的危害进行评估,进而采取控制的一种预防性的食品安全控制体系。有别于传统的质量控制方法,HACCP是对原料、各生产工序中影响产品安全的各种因素进行分析,确定生产过程中的关键环节,建立并完善监控程序和监控标准，采取有效的纠正措施，将危害预防、消除或降低到消费者可接受水平，以确保食品生产者能为消费者提供更安全的食品。     

地热水产养殖水温调节的流体控制分析

随着现代渔业的发展,许多专家学者已经对地热水产养殖的实际情况进行了数学建模,并根据分析和得出的结论设计了控制系统.此控制系统利用单片机搭建,根据温度和流量传感器的反馈,通过PID算法,用单片机产生PWM波对电机进行控制,调节地热水管和冷水管的流量,最终达到控制输出水温的目的.     

加压溶气气浮技术用于净化养殖水体的研究

采用一套自主开发研制的加压溶气气浮装置,对养殖水体中的微颗粒进行净化。选取液位高度、液体流量、溶气压力进行单因子试验和正交试验,单因子试验结果表明,液位0.8 m具有浊度去除的最佳效果;液位1.0 m对浊度去除率和pH的增加率的影响较显著;液体流量为400~600 L/h时,浊度去除率最大;液体流量为200~400 L/h时,溶解氧和pH增加率最大;溶气压力为0.5 MPa时,浊度的去除率达到了最大值的72%,同时,pH的增加率也达到了最大值,溶气压力为0.4 MPa时,溶解氧的增加率达到了最大值;通过正交试验得到三因素的最优组合为:液位高度1.0 m、液体流量200~400 L/h、溶气压力0.4 MPa。     

基于易控的工业化循环水养殖系统

随着可用水资源的减少,工业化循环水养殖是现代渔业的发展趋势。为了提高工业化循环水养殖的自动化程度,以及将其与物联网更好地结合起来,设计了基于易控的工业化循环水养殖系统。系统采用封闭式循环水养殖工艺,选用微滤机、流化床、低压纯氧混合装置等国内先进的循环水养殖装备构建硬件系统,使用西门子S7-300 PLC和其它智能仪表设备等构建控制系统,通过易控软件作为人机交互平台将各要素进行整合。该系统实现了工业化循环水养殖系统的养殖过程智能控制、养殖水质精准调控和养殖控制物联网化,具备自动化程度高、运行稳定、扩展性强的优点。该系统易于推广,并为将来的福利养殖系统提供了理论依据和基础数据。     

封闭循环水系统生物滤池气水比对水质净化效能的影响

通过在全封闭循环水系统中养殖半滑舌鳎(Cynoglossus semilaevis Gunthe), 研究了不同气水比对曝气生物滤池净化效能, 以及对DO、pH值的影响。结果表明: 本试验系统在温度为(19±1)℃, 系统循环次数为15次, 养殖池DO保持在12 mg/L以上的运行条件下, 随着气水比由0.75 : 1~1.50 : 1的增加, 生物滤池氨氮的去除率由35.0%增加至52.0%, NO₂-N的去除率由8.2%增加至44.6%, 气水比对硝化反应影响显著, 但对化学需氧量COD的去除率影响并不显著, 其平均去除率为10.14%; pH值有增加的趋势, 生物滤池进水口到出水口的pH值由7.97增加至 8.08; 气水比最佳运行参数为1.25:1。同时还发现1级生物滤池进水口DO接近饱和, 1级到末级滤池间DO仅降低了10%左右, 系统pH值在7.9~8.1。本研究所获参数, 可供生物膜法处理养殖循环水的条件优化作参考。

     

生物膜法SBR（BSBR）在循环养殖水处理中影响因素分析

膜法SBR（sequence batch reactor）是将SBR法与接触氧化法相结合的一种新型生物膜法处理工艺。此研究以总氨氮（TAN）及总氮（TN）的去除反应速度作为考察指标，分析生物膜法SBR（biofilm sequence batch reactor，BSBR）处理水产循环养殖系统水体中影响TAN及TN去除效果的主要因素。其中，pH和碱度对硝化反应有很大的影响，pH控制在6．3以上时TAN处理效果较好。溶解氧（DO）对反硝化反应也有较大的影响，同时考虑到水生生物的生长需求，在此试验系统中进入反应器的水体DO最好能控制在4．5～6．5mg·L^-1。水温保持在20％左右，可以保证有一个较好的脱氮效果。     

Design and performance of recirculating aquaculture system for marine finfish broodstock development

Tropical and subtropical climatic conditions in India present an ideal and unique opportunity for being the leader in tropical marine finfish aquaculture. However, the problem persist due to non-availability of marine finfish seed for the culture. In response to this problem, broodstock development of different tropical marine finfishes for seed production was started. The present study was undertaken to design a recirculating aquaculture system (RAS) and studying their performance in managing the various water quality required for the marine finfish broodstock development and breeding. The design of RAS, developed in the present study, included a broodstock tank, egg collection chamber, electrical pump, rapid sand filter, venturi type protein skimmer and biological filter. Two RAS were designed, one was stocked with a demersal fish species, orange spotted grouper (Epinephelus coioides) and the other was stocked with a pelagic fish species, Indian pompano (Trachinotus mookalee) at the rate 1 and 0.5 kg/m³ with a sex ratio of 1:1 and 1:2 (female: male) respectively. Various physio-chemical parameters, viz, total ammonia nitrogen (TAN), nitrite, nitrate, pH, alkalinity, temperature, free carbon dioxide (CO₂) and dissolved oxygen (DO) of both tank water were analyzed to assess the performance of recirculating aquaculture system in maintaining the water quality. Gonadal development of the fishes was assessed and the spawning performance was recorded and finally, economic performance of the system was also evaluated. During the entire experimental period, mean monthly total ammonia nitrogen was less than 0.07 and 0.06 mg L⁻¹ and mean monthly nitrite was less than 0.02 and 0.01 mg L⁻¹ in orange spotted grouper and Indian pompano RAS tanks respectively. The pH (7.8–8.2), DO (>4 mg/L) and alkalinity (100–120 mg/L) were found to be in optimum range in both recirculating aquaculture systems. Carbon dioxide was found to be nil during the entire experimental period in both the systems. In fact these levels were comparable or less than that is reported as the permissible limits for broodstock development. Indian pompano and Orange spotted grouper matured and spawning was obtained with production of fertilized eggs round the year. Economic evaluation showed the price of 10,000 fertilized eggs of orange spotted grouper to be US $ 1.33. The design of RAS devised in the present study is efficient in controlling and maintaining optimum water quality for broodstock development of both demersal and pelagic finfishes. The fishes stocked in RAS attained final maturation and round the year spawning was obtained.     

Design of water quality monitoring system for aquaculture ponds based on NB-IoT

In order to promote the development of aquaculture informatization and monitor aquaculture ponds more accurately and conveniently, this article has developed a water quality monitoring system for aquaculture ponds based on the narrow band internet of things (NB-IoT) technology. This system realizes remote collection and data storage of multi-sensor processor information (temperature, pH, dissolved oxygen (DO) and other environmental parameters), as well as intelligent control and centralized management of breeding ponds. The system uses STM32L151C8 microcontroller and sensor terminal real-time acquisition, such as temperature, pH value, dissolved oxygen. It realizes data aggregation and transmission over a long distance to the Internet of things (IoT) telecom cloud platform through the technology of NB-IoT. The software called Keil implement the data format design of wireless communication module and data transmission. Java is used to develop background monitoring applications for accessing cloud platform, controlling underlying devices and local data processing. It can not only send hypertext transfer protocol (HTTP) requests to monitor cloud platform data, but also issue commands to the underlying control module to control the startup and shutdown of equipment such as aerator. The system was implemented and tested in ChangZhou, JiangSu Province, China. The experimental results showed that the system can obtain water quality parameters in time. The temperature control accuracy is maintained at ±0.12℃, the average relative error is 0.15 %, the dissolved oxygen control accuracy is maintained within ±0.55mg/L, the average relative error is 2.48 %, the pH control accuracy is maintained at ±0.09, and the average relative error is 0.21 %. The system has stable overall operation, real-time and accurate data transmission, which can meet the actual production needs and provide strong data and technical support for further water quality regulation and aquaculture production management.     

Effects of different layouts of fine-pore aeration tubes on sewage collection and aeration in rectangular water tanks

Sewage collection and dissolved oxygen (DO) management have always been the focus of industrialized recirculating aquaculture. However, there are still no reports on how to achieve efficient sewage collection and increase DO in rectangular water tanks. In the present study, the performance of sewage collection and aeration in rectangular water tanks were compared among three fine-pore aeration tubes (disc-type diffuser, four corner-type diffuser and distribute-type diffuser) layouts at three airflow rates, 6, 18, and 30 m³/h. The results of computational fluid dynamics (CFD) modeling and bait collection tests revealed that sewage collection using the four corner-type diffuser was better than using the disc-type diffuser and the distribute-type diffuser. Using the four corner-type diffuser, a strip-shaped sewage collector could be set up at the bottom of the tank to collect sewage at an airflow rate of 18 m³/h and a disc-shaped sewage collector could be set up at the bottom of the tank to collect sewage at an air flow rate of 30 m³/h. In terms of aeration, volumetric oxygen transfer coefficient (K_La₂₀), standard oxygen transfer rate (SOTR), and standard oxygen transfer efficiency (SOTE) of the distribute-type diffuser were all the highest at the three airflow rates, followed by four corner-type diffuser, and finally the disc-type diffuser, indicating that the aeration performance in the distribute-type diffuser was optimal. However, there were no significant differences in K_La₂₀, SOTR, and SOTE between the four corner-type diffuser and the distribute-type diffuser at both 18 and 30 m³/h airflow rates. Therefore, four corner-type diffusers were the optimal choice for recirculating aquaculture, considering the sewage collection and aeration requirements. The results of the present offer novel insights on the application of CFD in recirculating aquaculture, in addition to basic data and theoretical guidance on how to achieve efficient sewage collection and aeration in recirculating aquaculture.     

脱二氧化碳装置对循环水养殖系统pH的影响

为了调节循环水系统中养殖水体的pH,根据气体交换原理,设计一种脱二氧化碳(CO_2)装置。采用该装置去除养殖水体中的CO_2,并对由于CO_2含量累积造成的pH下降进行调节,使养殖鱼类处在一个适宜的pH环境中。试验时水温控制在(25±0.5)℃,每1 h取水样测1次pH,每4 h测1次碱度。水样取自养鱼桶内的水,检测前先对水样用40μm孔径针头过滤器进行过滤处理,实验周期24 h。结果显示,循环水系统加装脱二氧化碳装置能有效去除CO_2,使水体稳定在一个适宜的pH范围(7.39~7.42);CO_2质量浓度呈降低趋势,24 h后由开始的13.16 mg/L降低到7~8 mg/L,降低近50%,而不加装脱二氧化碳装置的循环水系统CO_2质量浓度持续上升,24 h后增加到37 mg/L左右,pH持续降低,最终降低到6.72~6.81。研究表明,脱二氧化碳装置能够有效去除水体中的CO_2,使水体pH维持在一个适宜鱼类生长的范围。     

封闭循环水养殖哲罗鱼试验

在水温15~17℃下,将5 000尾平均体质量(10±3)g的哲罗鱼Hucho Taimen幼鱼饲养在由24个直径1 800mm×高1 000mm养殖池组成的封闭循环水系统中,以探索工厂化循环水养殖哲罗鱼的主要技术参数。经过8个月的养殖表明:养殖密度达到31.8kg/m~3,成活率96%,肥满度为1.01~1.30,鱼的平均体质量增加350g,体长增加21.3cm,鱼体生长状况良好。生物滤器两天反冲洗一次,有效提高了生物滤器的氨氮转化效率;紫外线消毒方式有效对系统进行了消毒杀菌;监测表明,系统水处理效果显著,其中NH_4~-平均浓度维持在(0.56±0.05)mg/L;NO_2~-含量为(0.15±0.05)mg/L;NO_3~-平均浓度为(41.86±2.62)mg/L;溶解氧为8.37~9.45mg/L;p H8.21~8.63。