Effect of UV-B radiation on the feeding behavior of the rotifer Brachionus plicatilis

Effect of UV - B radiation on the feeding behaviour of marine zooplankton is important to assessing the health harm of marine ecosystem due to the gradually enhanced UV - B radiation in air. However, there are a few studies on this topic. The feeding behavior of the rotifer, Brachionus plicatilis, under the treatment of UV - B radiation on five species of microalgae, i. e. , Chlorella sp. , Tetraselmis chuii, Isochrysis galbana Park 8701, Chaetoceros muelleri Lermumerman, and Nitzschia clostertum, was studied. The results showed that the filtering and feeding rates of the rotifer decreased significantly with the dose increase of UV - B radiation when fed with five species of microalgae respectively （ P 〈 0.05 ） which indicates UV - B radiation inhibits the feeding activities of the rotifer on microalage. The mixed culture experiments shows the rotifer preferred to feed Chlorella sp. , then C. muelleri, L galbana, N. clostertum and T. chuii in turn if without UV - B radiation. Under the highest dose of UV - B radiation treatment （2.70 kJ/m^2）, the rotifer preferred to feed C. muelleri, then Chlorella sp. , N. clostertum, L galbana and T. chuii in turn. Chlorella sp. , L galbana and C. muelleri became the more favorite foods of the rotifer while T. chuii and N. clostertum became less favorite foods. The change of feeding rate and feeding selectivity of zooplankton driven by the enhanced UV - B radiation will lead to the change in the structure of phytoplankton community.

Experimental analysis of pressure characteristics of catalyst powder flowing down a cyclone dipleg

An experiment was carried out for investigating pressure behavior of catalyst powders, with a Sauter mean diameter of 63.6 μm, flowing downward in a cyclone dipleg with 150 mm inner diameter and 9000 mm high. Time mean pressure and time series of pressure fluctua- tions were measured at different axial positions in the dipleg with particle mass fluxes ranging from 50.0 to 385.0 kg m-2s t. The experimental results showed that the time mean pressure in the dipleg increased progres- sively from the top section to the bottom section. The experimental phenomena displayed that the fluidization patterns in the dipleg can be divided into two types on the whole, namely the dilute-dense coexisting falling flow and the dense conveying flow along the dipleg. In the dilute- dense coexisting falling flow, the dilute phase region was composed of a length of swirling flow below the inlet of dipleg and a dilute falling flow above the dense bed level. With increasing particle mass flux, the dilute-dense coex- isting falling flow was gradually transformed to be the dense conveying flow, and the exit pressure of the dipleg increased considerably. The pressure fluctuations were closely related to the flnidization patterns inside the dipleg. In the dilute-dense coexisting falling flow, the pressure fluctuations in the dilute flow region originated from par- ticle clusters, propagating downward as a pressure wave; however, the pressure fluctuations in the dense flow region originated from rising gas bubbles, propagating upward. When the dense conveying flow was formed in the dipleg,the pressure fluctuations originated mainly from instability of the feed and the compressed gas, propagating down- ward. The standard deviation of the pressure fluctuations indicated that the intensity of pressure fluctuations first increased and then decreased with increasing particle flux.

Investigation on the Structure of Chute-feed and Card Auto-leveller and Their Selection of Technological Processes

Based on the structure of chute - feed and autoleveHer, an analysis of their working principle and the verification of their practical production results have been carried out. Finally, the future investigation direetiom of chute - feed and card autuleveller are put forward.

稀缺主焦煤高效重介分选工艺在吕家坨矿选煤厂的应用

针对吕家坨矿选煤厂原生产工艺存在的问题,分析了入选原煤煤质特性,采用超宽粒级原煤三产品重介质旋流器选煤工艺、新型煤泥重介质旋流器选煤技术-反分流分选工艺、粗精煤泥两段弧形筛组合脱泥回收技术进行技术改造。改造后工艺系统指标检测结果表明,改造可提高综合精煤产率1.78%,增加税前利润10573.2万元。

固相萃取-GC-MS法测定饲料中的沙丁胺醇

沙丁胺醇(salbutamol),化学名称1-(4-羟基-3-羟甲基苯基)-2-(叔丁氨基)乙醇(结构式如图1所示),俗称舒喘宁,属于β-兴奋剂类药物的一种,临床上用于治疗支气管哮喘.同时沙丁胺醇同克伦特罗(瘦肉精)一样还具有提高饲料的转化率,促进动物生长的作用.但是,这种药物容易在动物内脏、组织中蓄积残留,有很大的副作用.……

催化裂化反应-再生系统优化改造及效果

为适应原料重质化趋势的发展,一些新的催化裂化工艺技术得到快速发展,旧的催化裂化装置通过对反应-再生部分核心技术进行升级改造,有效提高了装置加工劣质原料的适应性。广州石化1.0 M t/a重油催化裂化装置采用密相环流预汽提快分(CSC)系统,CS-Ⅱ进料喷嘴和高效PV型旋风分离器对反应-再生系统进行升级改造,产品分布明显得到改善,总液收率提高1.21%;喷嘴汽耗减少1.6 t/h;催化剂耗量下降0.23 kg/t;并缓解装置烧焦负荷和气压机能力不足的瓶颈限制,加工能力提高,装置运行效果显著,经济效益得到增加。

催化裂化装置再生器二级旋分料腿结垢原因分析

为查明某催化裂化装置再生器二级旋分料腿结垢原因,对垢样进行元素分析,结果表明金属元素在样品催化剂细粉中进行了富集。通过X射线衍射分析,证明催化剂细粉发生了熔融和黏结。再生器二级旋分料腿结垢的主要原因:金属元素的富集降低了催化剂分子筛晶相结构崩塌温度。当CO及少量携带焦炭颗粒的细粉在二级旋分持续燃烧时,由于二级旋分内烟气夹带固体粒子很少,热阱作用减弱,使烟气温度骤升,当温度达到甚至超过催化剂细粉熔融温度时,细粉晶体结构破坏变为液相,在高速离心作用下黏附在料腿顶部形成垢层。通过再生器超温次数与垢样“年轮”层数关系比对,证明二旋料腿结垢与富氧再生环境及烧焦不均出现尾燃有对应关系,而金属元素富集降低了催化剂细粉的熔融温度。针对结垢原因,提出了相应的改进措施和建议。

淮北选煤厂Φ610-GT型煤泥旋流器应用探究

根据物料颗粒的受力情况,分析了煤泥旋流器直径、入料压力和矿粒直径之间的相关关系;通过对Φ610-GT型、SDMC500-1型煤泥旋流器进行单机检查试验,得到了二者浮沉试验数据,并对数据进行分析,得到了两种设备的降灰效果;此外,还对两种设备的可能偏差进行了计算,得出Φ610-GT型煤泥旋流器在现有条件下拥有更好的分选效果。

S-3GHMC440/260型超级重介质旋流器在南关选煤厂的应用

结合S-3GHMC440/260型超级重介质旋流器的入选原料煤粒度组成及密度组成分析,对超级重介质旋流器在南关选煤厂的应用进行评定。该超级重介质旋流器的单机检测结果表明,当入选<6 mm粒度占64.85%、>1.8kg/L密度级占60.96%的原料煤时,其处理能力可达310t/h,一、二段可能偏差分别低至0.027kg/L和0.033kg/L,分选精度高,吨煤电耗比原3GHMC1200/850A型无压给料三产品重介质旋流器降低约10%,应用效果较好。

浅谈“Feed流”媒体——以《今日头条》、《手机百度》为例

近几年,今日头条、手机百度、天天快报等"Feed流"媒体盛行一时,即使面临许多媒体的口诛笔伐,仍然有无数公司前赴后继,无数用户删了又安,其背后的原因是什么?本文中,笔者将从传播学中的"使用-满足"理论、"场景设定"理论出发,探讨这一现象。

Characterization of β-1,4-D-mannanase Produced by Bacillus subtilis MSJ-5

Properties of enzyme production of a Bacillus subtitles strain （ MSJ-5 ） isolated from soil were studied in the test. Enzyme production reached the peak when MSJ-5 being cultured in fermentation medium for 32 h. 6-1,4-D-mannanase was the main component of crude enzyme solution, test results showed that the optimal reaction temperature of the enzyme was 50 ℃, the optimum reaction pH was 7.0, and the enzyme was stable when pH was 5.0 -7.0. Hydrolysis test re- suits showed that β-1,4-D-mannanase produced by MSJ-5 had significant viscosity reduction effects on Konjak mannan, and the major hydrolysis product was man- nan oligosaecharide. The results indicated that 6-1,4-D-mannanase produced by B. subtilis MSJ-5 had application potential in feed ingredients and functional oligo- saccharides industry.

新阳选煤厂XGR-3000型干扰床分选机的改进

介绍了XGR-3000型干扰床分选机的工作原理、控制系统及技术特征,分析了其在使用过程中存在的问题,通过加装入料旋流装置和配套改造入料井,确保了分选机入料分布的均匀和分选床层密度的稳定,从而稳定了精煤灰分,提高了精煤产率。

Glyphosate-Residues in Roundup-Ready Soybean Impair Daphnia magna Life-Cycle

Herbicide tolerant plants such as Roundup-Ready soybean contain residues of glyphosate herbicide. These residues are considered safe and previous animal-feeding-studies have failed to find negative effects related to such chemical residues. The present study tests 8 experimental soy- meal diets as feed in groups (each containing 20 individuals) of test-animals (D. magna). The diets have different levels of glyphosate residues and we show that animal growth, reproductive maturity and number of offspring are correlated with these chemicals. The tested soybeans are from ordinary agriculture in Iowa USA and the residues are below the regulatory limits. Despite this, clear negative effects are seen in life-long feeding. The work enhances the need for including analysis of herbicide residues in future assessment of GMO.

水力分级旋流器分离粒度的选择与控制

针对官地选煤厂原煤重介旋流器脱泥入洗工艺存在水力分级旋流器分离粒度过细,引起浮选和浮精环节低效运行的问题,研究分离粒度与入料压力、旋流器直径之间的换算关系,并结合官地选煤厂的实践经验,当工艺要求分离粒度较粗时,应尽量选用直径较大的水力分级旋流器,通过调整入料压力和底流口直径能够小范围调整分离粒度。

分级旋流器操作参数的优化

为提升煤炭的分选效果,在对分级旋流器分级效果现状分析的基础上,通过设计试验方案对不同分级旋流器的操作参数下开展无冲水分级试验和冲洗水旋流器分级试验,得出不同操作参数对应的工作效果参数,并最终得出分级旋流器的入口压力、入料浓度以及冲水压力的最优解。

Estimation of Collection Efficiency Depended on FeedParticle Concentration for Axial Flow Cyclone DustCollector

A cyclone dust collector is applied in many industries. Especially the axial flow cyclone is the mostsimple construction and it keeps high reliability for maintenance. On the other hand, the collectionefficiency of the cyclone depends not only on the inlet gas velocity but also on the feed particle concentration. The collection efficiency increases with increasing feed particle concentration. However untilnow the problem of how to estimate the collection efficiency depended on the feed particle concentrationis remained except the investigation by Muschelknautz & Brunner~[6]. Therefore in this paper one ofthe estimate method for the collection efficiency of the axial flow cyclones is proposed. The applicationto the geometrically similar type of cyclone of the body diameters D_1=30, 50, 69 and 99 mm showedin good agreement with the experimental results of the collection efficiencies which were described indetail in the paper by Ogawa & Sugiyama~[8].

旋流器离心浓缩工艺参数的优化

为解决煤矿尾矿处理不当对环境以及生态平衡造成的影响,急需实现尾矿的资源化利用。在对水力旋流器基本结构及浓缩工艺流程分析的基础上,设计对旋流器浓缩效果验证的试验装置,并重点对入料压力、进料浓度、底流口直径、溢流口直径对旋流器浓缩效果的影响展开试验研究,得出最佳浓缩效果的工艺参数。

Effects of Garcinia kola “Bitter Kola” Powder on Sex Reversal, Survival and Growth Performance of Tilapia (Oreochromis niloticus L.)

This study was carried out in 2022 at the Itato agriculture community estate of fish hatchery in eastern Senegal with the aim of finding an alternative method to 17-α-methyl testosterone (MT) by using Garcinia kola “Bitter kola” powder to obtain Oreochromis niloticus male sex populations. 1800 fry of average size between 0.01 and 0.02 g were distributed in 12 aboveground tanks of 1 m3 each at a rate of 150 individuals/tank, following 6 duplicate treatments. The negative (B1 and B2) and positive (B3 and B4) control diets, to which between 0 and 60 mg/kg of 17alpha-methyl testosterone had been added respectively, were mixed with industrial feed containing 40% protein;the tank diets (B5 and B6), (B7 and B8), (B9 and B10) and (B11 and B12) contained 10 g, 20 g, 30 g and 40 g of Garcinia kola powder respectively for 1 kg of industrial feed con-taining 40% protein. These different treatments resulted in high proportions of males in the order of 97.03%;98.09% for the hormone and proportions of 94.03%;93.26% for 20 g of Garcinia kola extracts. In terms of weight growth, the best average weights for the hormone and Garcinia kola were 0.896 g and 0.980 g respectively. With regard to fish survival, the following results were recorded: 95.53% and 94.56% respectively for additions of 20 g and 30 g of Garcinia kola extracts to the feed supplied to the fish. On the other hand, a significant difference in the mortality rate of 35% and 5% respectively for the conventional hormone and 20 g of Garcinia kola extracts was observed. To conclude the study, it is recommended that further studies be carried out to determine the quality of the flesh, their life stages and the profile of the amino acids present in their proteins.

浓密旋流器系统试验研究

为进一步提升浓密旋流器的浓缩效果,保证选煤厂煤炭分选环节的效果,对浓密旋流器展开研究,在浓密旋流器结构及工作原理分析的基础上,设计浓密旋流器系统的试验方案,并重点对入料压力、溢流管中心直径和矿泥含量比例对最终所得产品的黏度、磁性物含量以及沉降速度等进行对比,得出浓密旋流器的最佳运行参数。

入口颗粒浓度对旋风分离器压力降影响的实验分析

旋风分离器的入口气流颗粒浓度对旋风分离器的压力降有重要影响。在入口气流颗粒质量浓度5~550g/m3范围内,对蜗壳式旋风分离器的压力降进行了实验分析。结果表明,随着入口颗粒浓度的增加,旋风分离器的压力降逐渐降低,尤其是开始阶段,降幅明显。除旋风分离器的入口部分压力损失外,旋风分离器的压力降主要由气、固两相流与器壁之间的摩擦损失和气、固两相流的旋转损失两部分构成,前者与入口气流速度有关,后者与旋转速度有关。随着入口颗粒浓度的增加,摩擦损失部分增加,但旋风分离器内的气、固两相流的旋转速度降低,旋转损失部分降低,综合结果是旋风分离器的总压力降降低。旋风分离器的压力降变化也使管路系统压力分布发生变化,导致入口流量发生变化,加入颗粒后通过旋风分离器的流量相对纯气相时的流量明显增加。最后,给出了入口气流颗粒浓度对旋风分离器压力降影响的计算方法。计算中考虑了加入颗粒后对切向速度的衰减作用,适用于高入口颗粒浓度的工况。