Nitrogen Budget in Recirculating Aquaculture and Water Exchange Systems for Culturing Litopenaeus vannamei

In order to investigate the culture characteristics of two indoor intensive Litopenaeus vannamei farming modes, recirculating aquaculture system(RAS) and water exchange system(WES), this study was carried out to analyze the water quality and nitrogen budget including various forms of nitrogen, microorganism and chlorophyll-a. Nitrogen budget was calculated based on feed input, shrimp harvest, water quality and renewal rate, and collection of bottom mud. Input nitrogen retained in shrimp was 23.58% and 19.10% respectively for WES and RAS, and most of nitrogen waste retained in water and bottom mud. In addition, most of nitrogen in the water of WES was TAN(21.32%) and nitrite(15.30%), while in RAS was nitrate(25.97%), which means that more than 76% of ammonia and nitrite were removed. The effect of microalgae in RAS and WES was negligible. However, bacteria played a great role in the culture system considering the highest cultivable cultivable bacterial populations in RAS and WES were 1.03×10~(10) cfu mL~(-1) and 2.92×10~9 cfu mL~(-1), respectively. Meanwhile the proportion of bacteria in nitrogen budget was 29.61% and 24.61% in RAS and WES, respectively. RAS and WES could realize shrimp high stocking culture with water consuming rate of 1.25 m~3 per kg shrimp and 3.89 m~3 per kg shrimp, and power consuming rates of 3.60 kwh per kg shrimp and 2.51 kwh per kg shrimp, respectively. This study revealed the aquatic environment and nitrogen budget of intensive shrimp farming in detail, which provided the scientific basis for improving the industrial shrimp farming.     

循环水养殖系统管理运行存在主要问题调查分析

【目的】了解循环水养殖系统在全国水产养殖企业中的实际使用情况及存在的问题。【方法】通过问卷调查形式,研究我国各省份水产养殖企业使用循环水系统的情况,包括养殖企业的经济效益与现状,循环水系统各单元在工厂化养殖中存在的主要问题以及未来公司发展计划。【结果】我国循环水养殖企业总体规模较小,养殖水体小于5 000 m3、系统造价小于200万元、年营业额小于500万元的公司分别占63.6%、54.5%、54.5%。养殖品种上,选择养殖鲽鲆类的企业最多(33.3%),对虾其次(30.3%)。多数循环水系统由科研机构协助构建,80%以上的系统单元为国产。反硝化系统、生物滤器、微滤机被认为是最难操控的单元(分别占58.3%、41.2%、27.6%)。企业选择使用循环水系统的主要原因是经济效益(63.6%),其次是水处理需求(54.5%)和符合环保政策的要求(48.5%)。93.3%的公司有扩大生产规模和旧系统升级改造的计划。【结论】降低运行能耗、提高运行稳定性,最终提高经济效益是未来循环水养殖系统发展需要努力的方向。     

Commercial Production of Tiger Puffer(Takifugu rubripes) in Winter Using a Recirculating Aquaculture System

Tiger puffer(Takifugu rubripes) is a promising species for aquaculture production because of its high value and limited supply. However, in the north of China, using sea cages to culture this species in winter is hampered by the fact that the seawater temperature is extremely low. Here, a large scale commercial production of tiger puffer has been successfully realized using a recirculating aquaculture system(RAS) from 3 October 2012 to 31 May 2013. The RAS was comprised of nine culture tanks(total water volume 200 m3) and stocked with approximately a total of 14400 fish(initial mean weight 160 g). The tiger puffer was hand-fed at a rate of 0.7% of total body weight per day, and the feed conversion rate was(1.21 ± 0.3) kg kg-1. The recycle water in RAS was treated by a sieve bend screen, a foam fractionator, a submerged biofilter, an UV sterilizer and a submersible aerator. During the whole culture period, an excellent water quality control was achieved in RAS. At the end of this experiment, the survival rate of tiger puffer was more than 98%. The final tank densities averaged 31.2 kg m-3, and the final individual mean weight was 440 g.     

Nitrogen Budget in Recirculating Aquaculture and Water Exchange Systems for Culturing <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>

In order to investigate the culture characteristics of two indoor intensive Litopenaeus vannamei farming modes, recirculating aquaculture system (RAS) and water exchange system (WES), this study was carried out to analyze the water quality and nitrogen budget including various forms of nitrogen, microorganism and chlorophyll-a. Nitrogen budget was calculated based on feed input, shrimp harvest, water quality and renewal rate, and collection of bottom mud. Input nitrogen retained in shrimp was 23.58% and 19.10% respectively for WES and RAS, and most of nitrogen waste retained in water and bottom mud. In addition, most of nitrogen in the water of WES was TAN (21.32%) and nitrite (15.30%), while in RAS was nitrate (25.97%), which means that more than 76% of ammonia and nitrite were removed. The effect of microalgae in RAS and WES was negligible. However, bacteria played a great role in the culture system considering the highest cultivable cultivable bacterial populations in RAS and WES were 1.03×10¹⁰ cfu mL^?1 and 2.92×10⁹ cfu mL^?1, respectively. Meanwhile the proportion of bacteria in nitrogen budget was 29.61% and 24.61% in RAS and WES, respectively. RAS and WES could realize shrimp high stocking culture with water consuming rate of 1.25 m³ per kg shrimp and 3.89 m³ per kg shrimp, and power consuming rates of 3.60 kw h per kg shrimp and 2.51 kw h per kg shrimp, respectively. This study revealed the aquatic environment and nitrogen budget of intensive shrimp farming in detail, which provided the scientific basis for improving the industrial shrimp farming.     

Evaluation of Feed and Feeding Regime on Growth Performance,Flesh Quality and Fecal Viscosity of Atlantic Salmon (Salmo salar L.) in Recirculating Aquaculture Systems

The effects of different feeds and feeding regimes on growth performance, flesh quality and fecal viscosity of Atlantic salmon(Salmo salar L.) in recirculating aquaculture systems(RAS) were investigated. Fish(initial body weight of 1677 g ± 157 g) were fed with four commercial feeds(Nosan salmon-NS, Aller gold-AG, Skretting salmon-SS and Han ye-HY) in two feeding regimes(80% and 100% satiation) for 78 d. The results showed that salmon specific growth ratio(SGR) and weight gain ratio(WGR) were significantly affected by feed type and feeding regime(P 0.05). Feed conversion ratio(FCR) varied between 0.93 and 3.40, which was significantly affected by feed type(P 0.05), and slightly improved with increased satiation degree. The activities of digestive enzymes including protease, lipase and amylase were also significantly affected by feed type and feeding regime(P 0.05), increasing with satiation degree. Flesh qualities for vitamin E, hydroxyproline(HYP), liquid loss and muscle p H among all groups showed significant differences(P 0.05), ranging from 26.67 to 29.67, while no obvious difference was found in flesh color. Fecal viscosity for different treatments showed no significant difference, though improvement was found in 100% satiation group. From present experiment, it was concluded that both feed type and feeding regime can affect the important quality attributes of Atlantic salmon.     

Effect of Hydraulic Loading Rate on the Efficiency of EffluentTreatment in a Recirculating Puffer Aquaculture SystemCoupled with Constructed Wetlands

Constructed wetlands （CWs） were integrated into an indoor recirculating aquaculture system of obscure puffer （Takifuguobscurus） for effluent treatment. The effect of hydraulic loading rate （HLR） on the efficiency of effluent treatment by CWs was ex-amined for over a month. The CWs were operated under brackish conditions （salinity 7.4-7.6） at 3 different HLRs （0.762, 0.633, and0.458 m d-1） 3 times, 10 days each. Overall, the CWs exhibited high efficiency in removal of total ammonium nitrogen （by81.03-92.81%） and nitrite nitrogen （by 99.40%-99.68%）. The efficiency of CWs in removal of total ammonium nitrogen, nitratenitrogen, total Kjeldahl nitrogen, total phosphorous, and total suspended solids （TSS） increased with the decrease of HLR. The CWsoperated at the 3 HLRs in a decreasing trend proves to be effective, providing a useful method for effluent treatment in commercialpuffer aquaculture systems.     

Application of CFD modeling to hydrodynamics of CycloBio fluidized sand bed in recirculating aquaculture systems

To improve the efficiency of a CycloBio fluidized sand bed(CB FSB) in removal of dissolved wastes in recirculating aquaculture systems, the hydrodynamics of solid-liquid flow was investigated using computational fluid dynamics(CFD) modeling tools. The dynamic characteristics of silica sand within the CB FSB were determined using three-dimensional, unsteady-state simulations with the granular Eulerian multiphase approach and the RNG k-ε turbulence model, and the simulation results were validated using available lab-scale measurements. The bed expansion of CB FSB increased with the increase in water inflow rate in numerical simulations. Upon validation, the simulation involving 0.55 mm particles, the Gidaspow correlation for drag coefficient model and the Syamlal-O'Brien correlation for kinetic granular viscosity showed the closest match to the experimental results. The volume fraction of numerical simulations peaked as the wall was approached. The hydrodynamics of a pilot-scale CB FSB was simulated in order to predict the range of water flow to avoid the silica sand overflowing. The numerical simulations were in agreement with the experimental results qualitatively and quantitatively, and thus can be used to study the hydrodynamics of solid-liquid multiphase flow in CB FSB, which is of importance to the design, optimization, and amplification of CB FSBs.     

基于波动方程正演模拟分析薄砂层含不同流体的AVO特征

塔河油田碎屑岩储层厚度较小,薄层AVO 特征受薄层内多次波反射以及薄层调谐效应和频率滤波效应影响,导致薄层
AVO 特征与厚层AVO 特征差异较大。为此,笔者设计了不同含油气性薄层砂体模型来进行波动方程正演模拟,得到了CRP道集记
录,提取了目的层反射振幅,基于入射波振幅计算了反射系数,从而获得了薄层地震正演AVO 曲线,分析了塔河油田碎屑岩储层含不
同流体时的AVO 特征,找出了实际地质条件下的含油气性与AVO 属性特征的对应关系,以指导地震剖面上的含流体预测工作。      

Application of Grain Size Analysis to Study Sedimentary Environment of Sand Dune in the Vicinity of Tumen River

The average size of the sand of dune in the vicinity of Tumen River is 0.12～0.30 mm, its standard deviation is 0.45～0.99 φ and the frequency cumulative distribution curve is divided into the single peak and the double peak. The Ski of the single peak is negative and the double peak is positive. There are two different areas in the plot of the Ski versus σi* It is shown that the sedimentary environment of the dunes is neritic deposit by the expressions of the grain-size parameters. All of the characters show that the sand dunes in Estuary of Tumen River may be the dunes of sea facies which were changed again by weathering and fluvialaction.     

Application of Grain Size Analysis to Study Sedimentary Environment of Sand Dune in the Vicinity of Tumen River

The dunes in estuary of Tumen River in China lie to the area between the Jiushaping and Fangchuan in the left bank of Tumen River (Fig.1). The dis-tance is about 15～20 km between the dunes and the coast. It ranges from China to D. P. R. Korea and Russia. The range of the height of dunes is about 15～20 m and the width is 100～200 m. By the re-connaissance, we protracted 9 section planes of the dunes and collected 40 sand samples of the dunes, and identified the sedimentary environment …     

补偿模糊神经网络在砂土液化势评价中的应用

在分析砂土液化影响因素的基础上,选取震级、地面加速度最大值、标准贯入击数、比贯入阻力、相对密实度、平均粒径、地下水位等7个因素作为评价指标,建立了砂土液化势评价的补偿模糊神经网络模型.通过对网络的学习训练和仿真检验,表明补偿模糊神经网络是进行砂土液化势预测评价的有效手段.     

虾—鱼—贝—藻多池循环水生态养殖模式的研究

建立了一种虾、鱼、贝、藻多池循环水生态养殖及水质生物调控系统 ,该系统包括对虾养殖、鱼类养殖、贝类养殖、大型海藻栽培等 4个功能不同的养殖区 ,1个水处理区及 1个应急排水渠。通过在封闭循环系统内不同池塘中放养生态位互补的经济动植物 ,对虾池水质环境进行生物调控。结果表明 ,循环系统内虾池水层悬浮物数量、COD值、氨态氮含量比对照组单养对虾池明显降低 (t检验 ,P <0 .0 1)。养殖后排放水不处于富营养化状态 (E <1)。投入每千克对虾饲料生产0 .6 6 7kg对虾 ,同时生产 0 .0 37kg罗非鱼、0 .738kg牡蛎、0 .4 37kg江蓠 ,饲料利用率和经济效益显著增加。该养殖模式还具有防病性、环保性、高效性等优点     

DEM与区域土壤侵蚀地形因子研究

地形是影响地表径流和土壤侵蚀的重要因素,坡度等指标是流域水文和土壤侵蚀预报的重要变量.DEM在区域土壤侵蚀中应用研究主要包括:如何实现对侵蚀区地形的表达,使之能准确、科学和有效地表达地形形态和侵蚀沟道网络结构;在多种尺度上,用什么指标实现表征地形对土壤侵蚀发生过程的影响;用什么方法提取或者处理地形因子,如何建立地形因子与土壤侵蚀关系.引入新的DEM理念和算法,应用高精度地形测量数据和数字地形图,改进DEM质量,考虑尺度效应并将已有地形因子研究与区域土壤侵蚀模型研究结合,是今后的主要研究方向.     

利用有益微生物改善养殖生态环境的研究

研究了噬菌蛭弧菌在实验室条件下对水产养殖中常见病菌的裂解能力及噬菌蛭弧菌和光合细菌对池塘生态环境的改善作用。结果表明 ,噬菌蛭菌对嗜水气单胞菌具有裂解作用 ,噬菌蛭弧菌和光合细菌结合使用对养殖环境具有明显的改善作用。 2 5d后实验组比对照组池塘中的细菌总数少 2个数量级 ,70d后实验组比对照组池塘中的细菌总数少 3个数量级 ;2 5d后对照组COD为 6 35mg L ,使用噬菌蛭弧菌浓度为 3、5、1 0mL m3 及光合细菌皆为 5mL m3 实验组的COD分别为 4 6 7、4 1 6、4 1 8mg L ;2 5d后对照组NH3 N为 0 4 9mg L ,使用噬菌蛭弧菌浓度为 3、5、1 0mL m3 及光合细菌皆为 5mL m3 实验组的NH3 N分别为 0 36、0 33、0 32mg L ,90d后对照组NH3 N为 0 4 1mg L ,使用噬菌蛭弧菌浓度为 3、5、1 0mL m3 及光合细菌皆为 5mL m3 实验组的NH3 N分别为 0 2 7、0 2 2、0 2 1mg L ;5 5d后对照组硫化物为0 0 1 1mg L ,使用噬菌蛭弧菌浓度为 3、5、1 0mL m3 及光合细菌皆为 5mL m3 实验组的硫化物分别为0 0 1 0、0 0 0 8、0 0 0 8mg L。     

改进的DWCS算法及其在弱硬实时系统中的应用

针对动态窗口约束调度算法中,单个任务到达调度处理节点时,系统存在着无效计算的缺点,本文提出了一个改进算法。该算法在保留原有算法优良性能的同时,能够降低计算复杂性,提高系统的性能。并证明了DWCS算法可以用于一般的弱硬实时系统中。     

近场动力学理论在区域地面沉降建模中的应用研究

地面沉降是由自然和人类活动共同作用导致的缓变性地质灾害,是区域可持续发展的重要影响因素。以往地面沉降在建模时需要地裂缝等不连续结构的位置、走向、深度等信息,在构建微分方程模拟时需假设模型连续,这对开展地面沉降-地裂缝-地面塌陷一体化模拟带来一定的局限性。于2000年出现的近场动力学理论提出以积分形式描述材料受力过程,方法具有无需先验知识与连续性假设的优点,在材料的疲劳、损伤、断裂等模拟研究中展现出良好的应用前景。本文综述了其在岩石水力压裂、滑坡、饱水岩土材料等领域的研究进展;提出了应用近场动力学进行区域地面沉降建模求解的一般方法;结合InSAR技术获取的沉降信息、三维地震频谱谐振勘探技术获取的地下结构与密度信息等,提出了模型的反演调参与优化方法。以北京东部梨园-台湖镇-张家湾镇区域为实验区,建立了其4 km×6 km范围、0.2 km深度的近场动力学地面沉降模型,以实验区地下水位月均下降速率为边界条件,对2007—2010年地面沉降过程进行模拟。模拟结果与实测值的平均绝对误差为18 mm,表明近场动力学在地面沉降建模中有较好的适用性。     

检纠错技术在嵌入式系统中的研究与应用

研究了目前数据传输、数据存储领域中广泛使用的CRC(循环冗余校验)以及RS码(Reed-Solomon码),在16位单片机环境中软件实现两种算法.并模拟出实际通信中信道的突发错误和随机错误,通过实验统计数据的方式比较两种检纠错算法,分析其在不同信道质量下的检纠错能力和对系统资源的消耗状况.系统通过简单的改造和移植就能成为其他嵌入式系统中的数据校验传输模块;同时为在构建特定信道环境下的嵌入式数据通讯系统时,选择合适的检纠错技术提供了理论和实验依据.     

一种新的ROAM算法及其在地形建模中的应用

地形建模是数字地形分析的重要基础工作。实时优化适应性网格算法（ROAM算法）是目前常用的地形建模方法。但ROAM算法应用于地形可视化实时渲染时要求原始数据为正方形,且渲染后常有裂缝产生,因而该法在地形建模实践中受到较大的限制。针对ROAM算法存在的上述不足,本文提出了基于内接正方形插值方法的改进ROAM算法。通过将多边形分割为一个内接正方形和多个边缘多边形,用多边形的一个顶点依次与其他顶点相连,使边缘多边形分割为多个三角形,并根据边缘三角形面积大小,确定是否对边缘多边形进行继续分割,由此解决数据源限定为正方形的问题,利用添加拆分点的方法消除地形渲染产生的裂缝。采用不规则地形的灰度图作为高程数据源进行地形模拟实验,结果表明：改进后的ROAM算法能够消除裂缝,且对数据源无约束性要求,降低了算法复杂度,提高了整体可视化性能,能够满足地形实时动态显示的要求。