Design and analysis of artificial bee-colony-based MPPT algorithm for DFIG-based wind energy conversion systems

In this article, the proposed maximum power point tracking (MPPT) method is designed by taking rotor speed as an optimization problem, which is solved by artificial bee colony (ABC) algorithm to generate the maximum power output. The main advantage of this algorithm is that its optimal solution is independent of the initial positions and requirement of lesser number of control parameters, which leads to simple and robust MPPT algorithm than other algorithm. Furthermore, the hill climb search and particle swarm optimization-based MPPT algorithm are also discussed and the results obtained by these are compared to verify the effectiveness of proposed algorithm. Simulations for MPPT control along with doubly fed induction-generator-based wind energy conversion system is carried out in MATLAB/Simulink environment. Three statistical methods are used to evaluate the accuracy of each MPPT algorithm. All results are analyzed and compared under randomly selected wind as well as real wind speed configuration. Comparison of both numerical and simulation results under two different varying wind speed conditions strongly suggest that the proposed ABC-based MPPT algorithm is superior than other two MPPT algorithms.     

Herbicide safeners: Tools for improving the efficacy and selectivity of herbicides

Abstract

Safeners (also known as antidotes) are chemical or biological agents that reduce the toxicity of herbicides to crop plants by a physiological or molecular mechanism. Commercialized safeners are mainly chemical compounds that enhance the tolerance of selected grass crops such as maize (Zea mays L.), grain sorghum [Sorghum bicolor (L.) Moench], rice (Oryza sativa L.), and wheat (Triticum aestivum L.) to chloroacetanilide, thiocarbamate, sulfonylurea, imidazolinone, and aryloxyphenoxypropionate herbicides. In practice, safeners are applied either to the crop prior to planting (seed safeners) or to the soil together with the herbicide, formulated as a prepackaged mixture. Safeners act as "bioregulators”; controlling the amount of a given herbicide that reaches its target site in an active form. A safener‐induced enhancement of the metabolic detoxification of herbicides in protected plants is the most apparent mechanism for the action of all commercialized safeners. Herbicide‐detoxifying enzymes such as glutathione transferases (GST), cytochrome P‐450 monooxygenases (CytP450), esterases, and UDP‐glucosyltransferases are induced by herbicide safeners. At the molecular level, safeners appear to act by activating or amplifying genes coding for these enzymes (e.g., GST).     

环境工艺方法论研究——归纳演绎法

归纳和演绎是两种不同的推理和认识现实的科学方法。一般地讲,演绎是由一般到特殊的推理,归纳是由特殊到一般的推理,在认识过程中二者是相互联系、相互补充的,是个别与一般的矛盾统一。本文论述了归纳演绎法的定义,在环境工艺中的应用成果及其所依据的哲学原理。     

Organohalogen exposure in a Eurasian Eagle owl (Bubo bubo) population from Southeastern Spain: temporal-spatial trends and risk assessment

Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and organochlorine insecticides (OCs) were analysed in 58 Eurasian Eagle owl (Bubo bubo) unhatched eggs collected between 2004 and 2009 in Southeastern Spain. Levels of p,p′-DDE were found to be higher than in eggs laid by other European owls in the same decade, probably due to the greater agricultural activity in our study area. Compared to other European raptors, exposure to PCBs can be considered intermediate, but low to PBDEs. Land use differences and prey availability were the rationale to divide the study area in two subareas in further assessments. Temporal trends of HCB, p,p′-DDE, β-HCH, PCBs and PBDEs were significantly different in each subarea, generally increasing over time in the Southern but decreasing or remaining stable in the Northern. On the contrary, levels of cyclodienes tended to decrease in both subareas. Dietary shifts with a greater amount of birds are suggested as a cause for increasing organochlorine loads in raptors. This may explain the increasing trend in the Southern territories. However, due to the proximity of most of these nests to Cartagena, an important industrial city, increasing environmental pollution cannot be ruled out. Although average levels of the compounds analysed are below threshold levels, 17% of the samples exceeded 400 pg g⁻¹ ww (wet weight), the LOAEC for Total TEQs. Moreover, a negative correlation between TEQ concentrations and the metabolizable fraction of PCBs (F_prob = 0.0018) was found when TEQs values were above 10 pg g⁻¹ ww. This could be indicative of hepatic enzymes induction in the birds exposed at higher concentrations, which are mainly breeding in the Southern subarea. These females could be suffering from Ah-receptor-related toxic effects, some of which have been related to altered bird reproduction. Finally, a significant negative correlation between p,p′-DDE levels and eggshell thickness (r = −0.469, p < 0.001) was observed, with about 17% of eggshell thinning for eggs with p,p′-DDE levels above 100 μg g ⁻¹ lw. The persistence of this degree of thinning over a period of time has been related to population declines in other raptor species.     

麻黄愈伤组织细胞的悬浮培养

用中麻黄幼苗的３种外植体进行了离体培养。不同外植体诱导愈伤组织的结果表明：最佳培养基为ＭＳ＋２ｍｇ／Ｌ２,４－Ｄ＋１ｍｇ／Ｌ６－ＢＡ;最佳外植体为下胚轴;用源于下胚轴的愈伤组织进行悬浮培养,从第３代开始建立起稳定的悬浮系。愈伤组织、悬浮培养细胞及培养液中都含有麻黄碱,悬浮培养液中的麻黄碱含量高于愈伤组织和悬浮培养细胞。表２参１２     

星肋小环藻、滇池铜绿微囊藻的春化作用

为认知星肋小环藻（硅藻）春季活动、滇池铜绿微囊藻（蓝藻）春夏大规模暴发的活动规律,通过确定生长温区后进行变温实验,分析低温对2种实验藻的生长影响,其结果为：小环藻的生长温度为9.5～15.0℃,微囊藻生长温度为15.0～31.0℃,生长高温将抑制2种藻的生长;15.5℃以上、9.0℃以下时小环藻停止生长,31.0℃以上、15.0℃以下时微囊藻停止生长;在15.5～17.5℃停止生长后用7.0～9.0℃处理一天后放回生长温度培养,小环藻恢复生长,在31.0～33.0℃停止生长后用7.0～14.0℃处理一天后放回生长温度培养,微囊藻恢复生长,表明特定低温可使处于高温休眠的藻恢复生长,即低温具有解除高温休眠的作用;诱导低温7.5～9.5℃、10.0～14.0℃时,星肋小环藻、铜绿微囊藻的生长与低温诱导强度反相关,与诱导时间正相关;低温可解除高温休眠作用诱导藻生长,同样,高温也可解除藻的低温诱导作用。分析认为：星肋小环藻、铜绿微囊藻的低温诱导作用与植物春化作用一致,因此实验藻具有春化作用,其年活动规律为：经冬季低温诱导,处于休眠的实验藻春季恢复生长,夏季生长高温抑制铜绿微囊藻生长,秋季无诱导低温过程,铜绿微囊藻华可发生但不如春夏。     

不同矿井煤样变形破裂过程中的电荷感应实验研究

采用单轴压缩煤电荷感应信号测试系统,研究了不同矿井煤在不同加载速度下变形破裂过程中的电荷感应规律。研究结果表明,煤样在加载初期即有电荷感应信号,随着应力水平的增加,不断有电荷感应信号产生,且信号幅值不断增加,在应力峰值前后电荷感应信号最强,信号也最为丰富,煤样主破裂发生后仍有明显的电荷信号,但信号幅值较小;在煤样应力发生突变时有较强的电荷感应信号产生;抗压强度越高、冲击倾向性越强的煤样,电荷感应信号也越强,信号越丰富,持续时间越长;加载速度越大,所产生的电荷感应信号越强。电荷感应信号与煤的变形破裂和煤样类型有一定关系,可以用电荷感应信号反映煤的破坏程度。     

Systemically-induced response of cabbage plants against a specialist herbivore, Pieris brassicae

Summary. Plant responses to herbivory might directly affect the herbivore (“direct” defences) or might benefit the plant by promoting the effectiveness of natural antagonists of the herbivores (“indirect” defences). Brussels sprouts attacked by Pieris brassicae larvae release volatiles that attract a natural antagonist of the herbivores, the parasitoid Cotesia glomerata, to the damaged plant. In a previous study, we observed that feeding by caterpillars on the lower leaves of the plant triggers the systemic release of volatiles detectable by the parasitoids from upper leaves of the same plant.?The role of these systemically induced volatiles as indirect defence and the dynamics of their emission were investigated in wind-tunnel dual choice tests with C. glomerata. The systemically induced emission of volatiles varied depending on leaf age and on plant age. Systemic induction affected parasitoid effectiveness, as induced plants could be more easily located by parasitoids than non-induced ones.?The role of the systemic induction as a direct defence was investigated through behavioural and feeding tests with P. brassicae. In dual choice assays, 1st instar larvae preferred to feed and fed more on systemically induced than on non-induced leaves. In single choice assays, the leaf area consumed by caterpillars was larger on systemically induced leaves than on non-induced control leaves. However, caterpillars fed on systemically induced leaves attained the same weight as those feeding on non-induced controls. In addition, P. brassicae pupae whose larvae were fed on systemically induced leaves had longer developmental times than those of larvae fed on non-induced leaves. Adult oviposition behavior was not influenced by systemic induction.?We conclude that systemically induced responses in cabbage might reduce P. brassicae fitness both directly, by affecting their development and feeding behavior and indirectly by making caterpillars and pupae more vulnerable to attack by carnivores. The occurrence of a possible relationship between direct and indirect defence is discussed. Received 24 January 2001; accepted 3 May 2001.     

鲫鱼肝脏中CYP1A1的诱导作为沉积物中二的毒理学指标的研究

在实验室内用鲫鱼分别暴露于含有PCDD/Fs和PCBs严重污染的沉积物和未受污染的沉积物中,测定鱼肝脏中细胞色素P4501A1（CYP1A1）依赖的7－乙氧基－3－异吩唑酮－脱乙基酶（EROD）的活性。结果表明,鲫鱼暴露于受二类化合物污染沉积物中1周后,肝脏中EROD的活性是对照组的83倍,而未被污染的沉积物暴露试验中EROD的活性和对照组没有明显差别。在此沉积物－水实验系统中二类污染物的TCDD等当量浓度（TEQ/L）与肝脏EROD的活性有较好的相关性。较长时间暴露,得到肝脏EROD的活性随时间的变化关系。还获得了试验温度对EROD活性诱导的影响。此实验表明,用实验室鲫鱼暴露于沉积物－水系统中,鱼肝脏EROD活性诱导可作为沉积物毒性评价指标,用于受二类化合物污染的沉积物样品的筛选,并有希望成为此类污染物的半定量检测方法。     

几种胁迫因素对绞股蓝愈伤组织中皂甙积累的影响

将ＭＳ＋ρ（２,４Ｄ）０．５ｍｇ·Ｌ－１＋ρ（ＢＡ）１０ｍｇ·Ｌ－１培养基的Ｍｎ２＋浓度提高２０倍时可使绞胶蓝愈伤组织培养物的皂甙产率增加９１％,而提高Ｃｕ２＋浓度对皂甙积累的影响不显著;培养基中加入６８０ｍｍｏｌ·Ｌ－１的甘露醇可使皂甙产率提高８３％,但加入ＮａＣｌ则会降低皂甙产量;适当浓度的米曲霉和根霉提取物可使皂甙产率分别提高９７％和４２％．由ＴＬＣ图谱可见,绞股蓝愈伤组织中的皂甙组成与原植物相似,但出现一个新组分;原个别组分在不同的胁迫条件下有差别地消失．