Effects of salinity on egg and fecal pellet production, development and survival, adult sex ratio and total life span in the calanoid copepod, A cartia tonsa:a laboratory study

The ef fects of salinity on the copepod, A cartia tonsa in terms of daily egg production rate(EPR), hatching success, fecal pellet production rate(FPR), naupliar development time and survival, sex ratio, and total life span were determined in laboratory conditions through three experiments. In experiment 1, EPR, hatching success, and FPR of individual females were monitored at salinities of 13, 20, 35 and 45 during short-periods(seven consecutive days). Results show EPR was aff ected by salinity with the highest outputs recorded at 20 and 35, respectively, which were considerably higher than those at 13 and 45. Mean FPR was also higher in 35 and 20. In experiment 2, the same parameters were evaluated over total life span of females(long-term study). The best EPR and FPR were observed in 35, which was statistically higher than at 13 and 20. In experiment 3, survival rates of early nauplii until adult stage were lowest at a salinity of 13. The development time increased with increasing of salinity. Female percentage clearly decreased with increasing salinity. Higher female percentages(56.7% and 52.2%, respectively) were signifi cantly observed at two salinities of 13 and 20 compared to that at 35(25%). Total longevity of females was not af fected by salinity increment. Based on our results, for mass culture we recommend that a salinity of 35 be adopted due to higher reproductive performances, better feeding, and faster development of A. tonsa.

Modeling and Analysis on Production Yield and Energy Consumption of Pelleting Process

The existing studies on the pelleting process were reviewed, and then the forming process of pelleting was introduced. Furthermore, the models describing the production yield and energy consumption of pelleting were presented. Based on the models, the influence of the pelleting structure parameters, die speed on the production yield and energy consumption were discussed. The results showed that larger pellet mill was preferred and the proper speed of the die should be selected to increase the production yield and reduce the energy consumption.

Effect of Pelleted Total Mixed Ration on Production Performance and Serum Biochemical Index of Growing Hainan Black Goats

[Objective] The paper was to investigate effects of pelleted total mixed ration on production performance and serum biochemical index of growing Hainan black goats.[Method] Twenty-four growing Hainan black goats with the same genetic backgrounds and similar initial weight of(10.05±0.049) kg were randomly assigned into two treatments, and supplied with Juncao + concentrate(control group), pelleted total mixed ration(experimental group), respectively. The trial lasted 50 d.[Result] The final weight, daily gain and feed intake of experimental group were significantly higher than those of control group(P<0.05), but the feed/gain ratio of experimental group was markedly lower than that of control group(P<0.05). Compared with the control group, the gross profit of experimental group significantly increased( P <0.05).[Conclusion] Pelleted total mixed ration led to better production performance of growing Hainan black goat.

Carbon biomass,production rates and export flux of copepods fecal pellets in the Changjiang(Yangtze) River estuary

Copepod fecal pellets are ubiquitous throughout the oceans. Their production and export can represent a highly efficient pathway of carbon export. However, the role these fecal pellets play in carbon export in the Changjiang(Yangtze) River estuary is not well known. Two cruises were carried out in the Changjiang estuary in the spring and summer of 2013, during which time carbon biomass, production, and export of copepod fecal pellets were studied. Spring and summer fecal pellet carbon biomass ranged 0.30–1.01 mg C/m^3(mean=0.56±0.20 mg C/m^3) and 0.31–1.18 mg C/m^3(mean=0.64±0.24 mg C/m^3), respectively, significantly lower than phytoplankton. At most stations, fecal pellet carbon biomass was higher in surface or subsurface layers than deeper layers. Production rates ranged 0.65–1.49 pellets/(ind.?h)(mean=1.02±0.27 pellets/(ind.?h)) in spring and 0.62–1.34 pellets/(ind.?h)(mean=0.98±0.22 pellets/(ind.?h)) in summer, within the range reported in previous studies. Higher production rates of fecal pellets occurred at stations with higher chlorophyll a concentrations, and production rates of copepods of size 500–1 000 μm greater than copepods >1 000 μm during both cruises. The potential export flux of fecal pellets was slightly higher in summer(mean=68.95±14.37 mg C/(m^2 ?d)) than spring(mean=52.08±11.33 mg C/(m^2 ?d)) owing to higher summer copepod abundances. To our knowledge, this study is the first of its kind in the Changjiang estuary, and it confirms the significant role of copepod fecal pellets in local carbon export.

Effect of Pelleted Total Mixed Ration of Different Particle Sizes on Production Performance and Serum Biochemical Index of Fattening Hainan Black Goats

[Objective] The paper to investigate the effects of pelleted total mixed ration of different particle size on production performance and serum biochemical index of fattening Hainan black goats.[Method] Thirty-six fattening Hainan black goats with the same genetic backgrounds and similar initial weight of(19.02±0.22) kg were randomly divided into three treatments. Goats were fed with Juncao+concentrate(control group), pel-leted total mixed ration I(particle size 6 mm, experimental group I) and II(particle size 5 mm, experimental group II), respectively. The trial lasted 45 d.[Result](1) The final weight and daily gain of experimental group II were significantly higher than those of control group( P<0.05), and the daily gain of experimental group II was also higher than that of experimental group I(P<0.05);the feed intake of experimental group II was markedly higher than that of control group(P<0.05), but was significantly lower than that of experimental group I(P<0.05). The feed/gain ratio of experimental group II was significantly lower than those of control group and experimental group I(P<0.05).(2) The feed gain cost of experimental group II was markedly lower than that of control group(P<0.05), but the gross profit was significantly higher than those of control group and experimental group I(P<0.05).(3) Compared with the control group, the serum total protein content of experimental group II increased markedly( P<0.05) while the urea nitrogen level decreased(P>0.05).[Conclusion] The pelleted total mixed ration with the particle size of 5 mm obtained better fattening ef-fect, and obviously improved the serum total protein level.

唐钢基于高比例球团冶炼的高炉设计与生产实践

为贯彻“绿色、低碳”的发展理念,唐钢沿海钢铁基地炼铁系统从设计之初即针对球团矿的物化和冶金性能特点,从炉型结构、冷却壁设计等进行诸多优化。投产以来,通过提高焦炭质量、改善熔剂性球团低温还原粉化性能(RDI+6.3)、稳定炉料结构、优化操作制度等措施,在唐钢目前原燃料条件下,球团矿入炉比例稳定在40%以上,高炉实现长周期稳定顺行,燃料比、煤比分别控制在520 kg/t和170 kg/t左右。

Effect of Pelleted Total Mixed Ration with Different Concentrate-roughage Ratios on Production Performance and Serum Biochemical Parameters of Fattening Hainan Black Goats

[Objective] This paper was to study effects of pelleted total mixed ration with different concentrate-roughage ratios on production performance and serum biochemical parameters of fattening Hainan black goats.[Method] Thirty-six fattening Hainan black goats with the same genetic background and similar initial weight of(14.08±0.13) kg were randomly assigned into three treatments. Goats were fed with Juncao + concentrate(control group), pelleted total mixed ration I(concentrate: roughage 50 ∶50, group Ⅰ) and Ⅱ(concentrate: roughage 45∶55, group Ⅱ), respectively. The test lasted 45 d.[Result] The final weight, daily gain and feed intake of rams in experimental group Ⅰ were significantly higher than those of control group and experimental group Ⅱ(P<0.05);the final weight and daily gain of rams in experimental group Ⅰ were also markedly higher than those of experimental group Ⅱ(P<0.05);the feed/gain of rams in experimental group Ⅰ was significantly lower than those in control group and experimental group Ⅱ(P<0.05). The feed gain cost of rams in experimental group Ⅰ was markedly lower than that in experimental group Ⅱ( P<0.05), but was significantly higher than that in experimental group Ⅰ(P<0.05);the gross profit of rams in experimental group Ⅰ was significantly higher than those in control group and experimental group Ⅱ(P<0.05). Compared with control group and experimental group Ⅱ, the serum total protein and glucose lev-els in experimental group Ⅱ increased significantly(P<0.05), but the urea nitrogen content reduced(P>0.05).[Conclusion] When the concentrateroughage ratio of pelleted total mixed ration was 50∶50, the fattening effect of Hainan black goat was better, and the serum total protein and glucose levels were evidently improved.

带式焙烧机节能减排效果实践

带式焙烧机作为生产高炉主要原料球团矿的主流设备,以其特有的优势成为契合目前以及未来钢铁企业生产的最佳途径之一。通过介绍现阶段新兴铸管带式焙烧机生产实际情况,阐述了带式焙烧机在钢铁行业的显著优势,以期为钢铁行业在节能减排方面提供思路,为实现行业绿色高质量发展提供借鉴与参考。

带式焙烧机球团NOx超低排放技术研究现状与展望

总结了带式焙烧机NOx的产生机制,揭示了带式焙烧机产生NOx的主要因素,探索从焙烧过程中可降低NOx产生的措施;并结合最新烟气强化脱硝技术和强化手段,为带式焙烧机烟气脱硝技术改造做理论支持和铺垫。

电商价值链对农产品营销的影响研究——以宝庆丸子为例

本研究以宝庆丸子为例,探讨了电商价值链对农产品营销的影响。通过扎根调研等方法,对宝庆丸子的销售数据、消费者反馈、营销策略等方面进行分析,揭示了电子商务在推动农产品地区品牌建设、优化供应链管理、扩大销售范围和提升用户购买体验中的关键作用。研究发现,通过有效构建电商价值链,宝庆丸子的销售商能够减少中间环节,降低营销成本,同时通过大数据分析更好地理解消费者需求,实现产品创新和营销策略的精准定位。

骨粒厂生产废水预处理试验研究

骨粒厂生产废水具有很高的化学需氧量(Chemical Oxygen Demand,COD),同时含有大量蛋白胶体物质及细骨粉。以往采用蒸发浓缩处理生产废水,这种方法处理成本高且存在一定安全风险。该生产废水含有高浓度的有机物,具有可生化性。通过试验探索骨粒厂生产废水预处理方法,分析不同药剂对生产废水中蛋白的分离效果。预处理后,生产废水中骨粉与蛋白实现分离,脱蛋白后的废水进行生化处理,处理后废水进一步回用,实现废水零排放。研究结果表明,骨粒厂生产废水原水加入聚合氯化铝(Polyaluminum Chloride,PAC)、聚丙烯酰胺(Polyacrylamide,PAM)与石灰组合的混凝剂调理后,蛋白分离效果较好。

高品质球团配矿结构工业生产试验研究

为寻求宣钢公司氢冶金气基竖炉球团实际生产最佳的原料结构和关键工艺参数控制范围等,通过开展球团配矿结构工业生产试验,对其生球性能、成品球团矿理化性能,以及气基竖炉气氛条件下的还原性能、还原膨胀、黏结性能等指标进行分析比对研究,明确了球团实际生产配矿最佳结构排序及适宜的关键工艺参数控制范围等,且通过试验表明,在现有工艺装备和技术操作水平条件下,公司生产氢冶金气基竖炉用球团矿是可行的,进而为气基竖炉项目投产后,能顺利实现达产、达效奠定基础保障,同时为后续球团原料结构再优化指明改进方向和提供借鉴。

基于PID的饲料制粒调质温度控制系统设计与试验

为解决颗粒饲料在制粒过程中调质温度依赖人工辅助控制问题,该研究设计了基于PID控制算法的调质温度控制系统。采用开环阶跃响应法建立电动比例调节阀与调质温度之间的控制模型。为了得到最优的PID控制参数(比例系数K_(p)、积分系数T_(i)、微分系数T_(d)),通过Simulink仿真试验对比了Ziegler-Nichols整定法、衰减曲线法和临界比例度法的PID响应曲线,确定PID最优控制参数为K_(p)=52.7,T_(i)=6.4,T_(d)=1.6。对小型制粒机调质温度控制系统进行试验,选用哺乳母猪配合粉料,调质温度分别设定为75、80和85℃,稳定后的调质温度均能维持在设定范围内;选取调质温度为80℃进行稳定性试验,每1 min记录调质温度,整个试验过程中调质温度基本稳定在(80±1)℃范围内,调质温度平均相对误差小于1%,调质温度变异系数小于0.5%,系统温度控制稳定,可自动采集制粒生产数据,实现了制粒过程中调质温度的快速响应和实时控制。研究结果可为颗粒饲料制粒机的自动化控制提供参考。

饲喂不同料型对种鹅产蛋前期生产性能的影响

为观察不同料型对种鹅繁殖性能的影响,在产蛋前把种鹅随机分为2组,试验Ⅰ组1 332只,试验Ⅱ组1 340只,每组设置6个重复。开始产蛋后试验Ⅰ组种鹅饲喂颗粒饲料,试验Ⅱ组种鹅饲喂粉料。观察记录种鹅采食量、产蛋性能和种蛋质量等指标,进行统计分析。结果表明,试验Ⅰ组种鹅采食量、产蛋率上升速度显著高于试验Ⅱ组(P <0.05),但产蛋高峰期种蛋受精率显著低于试验Ⅱ组(P<0.05)。饲喂颗粒饲料可以提高种鹅的采食量和产蛋高峰期的产蛋率上升速度,饲喂粉料可以提高种鹅的种蛋受精率。

硅热法炼镁增产提质的原理探索与应用

在硅热法炼镁工艺中,还原罐和结晶器的工作原理导致罐口附近一定存在大梯度降温区,但关于还原罐罐口附近温度场对料镁比(料球和所产镁的质量比)影响的研究鲜见报道。本文设计并搭建了能定位测温的近生产条件的实验装置,测量发现罐口附近的低温区导致料球反应率降低,料镁比提高。为了提升罐口附近温度,本文设计了一个阻止热量散失的装置。结果表明:使用阻热装置后,罐口附近温度显著提升,并使料镁比从6.3降至5.95;同时该装置还可使粗镁纯度从不足国标Mg9980升至Mg9995A,兼具通过梯度冷凝去除杂质的功效。

自动造球技术在球团生产中的应用

造球工序是球团生产工艺流程中的一个重要环节,生球质量和产量直接影响成品球团矿的质量、产量及能耗水平。目前造球盘加水使用手动加水方式,调节精度差、响应时间慢,已经无法满足球团厂的自动化生产需求,现在迫切需要开发一套自动造球系统,实现造球盘的自动控制。

唐钢带式焙烧机熔剂性球团矿生产实践

为适应高炉高比例球团冶炼的需求,从2021年初开始唐钢新区使用带式焙烧机生产熔剂性球团。通过改造消石灰配给设备,改变除尘灰配加方式,增加细粒铁精粉配比,降低抽干段、预热段以及焙烧段的温度,严格控制熔剂性球团矿SiO_(2)不超过3.5%及TiO_(2)含量不超过0.5%等技术措施,使得熔剂性球团矿化学成分稳定性得到明显改善,低温还原粉化RDI+6.3指标由70%左右提高到93%左右,为高炉实现35%熔剂性球团配比下的长周期稳定顺行提供了保障。

成品球团矿自动倒仓控制系统的设计与应用

成品输送和存储是球团生产的主要环节,而传统运储的方式无法及时、准确地根据现场作业频繁多变的情况对设备和资源进行全面地协调管理。通过分析成品倒仓系统的工艺、控制要求和控制过程,并在数据处理和控制方法上进行深入地研究,在原有电气控制系统的基础上,新增一套远程自动控制系统。自动控制系统通过对过程变量的实时监测、生产工艺的实时监控和过程参数的实时控制以实现成品仓位的不间断监测及移动漏矿车的实时控制与定位。

球团成品仓步进式自动放料系统研究

球团成品仓放料一般为人工操作,人工成本高,装载效率低,放料过程中产生的粉尘会危及工人健康,造成职业病。简要介绍了自动放料系统的工作原理、构成及计算方法等,详细阐述了步进式放料逻辑,通过现场应用实测,结果表明:自动放料系统各项指标基本达到了预期要求,为球团成品仓步进式自动放料系统的正式应用积累了经验。