Hydraulics for small fishing trawlers

Fishing vessels where electric power supply from alternator is available to operate various auxiliaries located anywhere in the vessel, the small crafts, which constitute over 95% of the total fishing crafts operating in India, are entirely dependent on one source of power, i. e. the main diesel engine. To utilize this source of motive power to operate the winches and other auxiliaries, mechanical drive involving shafts, bearings and pulleys, is inconvenient. This paper presents basic advantages of hydraulic system over mechanical drive.

Development of a fishing log for use in trawlers

The paper describes the technical and operational features of a composite equipment for simultaneous measurement of five important parameters, warp load, boat speed, water temperature, water salinity and air temperature pertaining to the craft, gear and the environment. The equipment is designed for continuous measurement in small and medium crafts easily without disturbance to routine fishing operations. The system operated on 9V supply, is suitable for portable operations from one vessel to another. The compact electronic meter kept in the wheel-house displays the data one by one in engineering units.

Impacts of fishing gears, fishing methods and fishing effort in the fisheries of Lake Victoria and proposals for management

The initial subsistence fisheries of Lake Victoria were dominated by two indigenous tilapiines, Oreochromis esculentus (Graham 1929) and Oreochromis variabilis Boulenger 1906, exploited with simple fishing crafts and gears that had little impact on the fish stocks (Jackson 1971). Commercial fisheries, targeting the tilapia fishery, started at the beginning of the 20th Centurywhen cotton flax gillnets were first introduced in 1905 into the Nyanza Gulf in Kenya. Gillnets were quickly adopted around the whole lake and consequently, the native methods of fishing soon died out (Jackson 1971). Following the introduction of gillnets, fishing boats and their propulsion methods were also improved. These improvements in fishing capacity coincided with development of urban centres and increasing human population around the lake, which increased the demand for fishery products. To satisfy the increasing demand, fishing effort increased greatly during the 20th century, despite the decline of catch per unit of effort (CPUE) (Jackson 1971; Ogutu-Ohwayo 1990). The initial catch rates of 127mm (5 inch) mesh size gill nets in the tilapia-based fishery, in 1905, was in the range of 50 to 100 fish per gillnet of approximately 50 m in length. However, twenty years later, the catch rates of gillnets of the same mesh size had declined to about six fish per net and gillnets of smaller mesh sizes, which had better catch rates, had been introduced suggesting overfishing (Worthington and Worthington, 1933).

National report of the frame survey 2012 on the Uganda side of Lake Victoria

This is a report on the results of the Frame Survey conducted in the Uganda side of Lake Victoria during August 2012 by the LVFO Institutions, namely: the Department of Fisheries Resources (DFR) Uganda and the National Fisheries Resources Research Institute (NaFIRRI) in close collaboration with the District Fisheries offices of Busia, Bugiri, Namayingo, Mayuge, Jinja, Buvuma, Buikwe, Mukono, Kampala, Wakiso, Mpigi, Kalungu, Masaka, Kalangala and Rakai. In the 2012 Frame survey some indicators of fishing effort including e.g. number of fishers, fishing crafts and long line hooks increased; whereas others like the number of gillnets less than 5 inches decreased by 10.4% from that recorded in 2010. The other indicators of fishing effort, which showed decrease in 2012 included illegal beach seines and undersized gillnets (<5 inch mesh size). However, a large proportion (66%) of long line hooks recorded in the 2012 survey were in the smallest size range (hook size >10), which target small Nile perch. The number of other illegal gears, i.e. cast nets and monofilament gillnets showed modest increases (25%) between 2010 and 2012 while beach seines decrease by 15%. Recent crackdown on illegal fishing activities as part of measures for recovery of the Nile perch stocks which are faced with depletion appear to have had an impact but much more needs to be done to eradicate illegal fishing. The fisheries in the Ugandan waters have remained predominantly near shore with 61% of all fishing crafts using paddles out of which 17% were tiny three plank, flat bottomed boats locally known as parachutes. The 2012 survey shows an increase in the number of fishing crafts using sails by 65% from 682 in 2010 to 1125 in 2012. This is an encouraging trend as more fishers are able to access distant fishing grounds using free wind power. The Mukene fishery in the Ugandan waters of Lake Victoria remained underdeveloped comprising only 15.2% of all fishing crafts, of which 31% were motorised which is a great improvement from the situation recorded in 2010. The Catamarans increased to 18 with a majority in Buikwe district where there is a private investor fishing specifically for Mukene. The Catamarans in Kalangala were reported not to be working because of the high operating cost compared to ordinary Mukene fishing boats.

Lewis酸引发的LLDPE/PS共混体系的原位反应增容及其结构与性能研究

本文以单组分和双组分Lewis酸为催化剂，采用反应加工的方法，制备了原位反应增容的线性低密度聚乙烯/聚苯乙烯共混物（LLDPE/PS），并对原位反应增容的机理、增容体系的结构性能以及Lewis酸对共混组分的降解作用进行了系统研究。 以FTIR和NMR为手段、二甲苯为模拟化合物，确认LLDPE/PS共混体系在Lewis酸为催化剂作用下发生了LLDPE与PS的接枝反应，LLDPE接枝在PS苯环的对位上。形成的原位接枝共聚物对体系起增容作用。 使用溶剂抽提、SEM、DMA、流变和DSC等手段对以单组分Lewis酸AlCl3 为催化剂的LLDPE/PS共混物的结构性能进行了研究。从溶剂抽提前后的重量比计算了接枝物的含量。催化剂用量较低时体系中的接枝物含量随AlCl3的增加而提高，随着AlCl3进一步增加，接枝物含量不会增加反而下降，发现AlCl3导致均聚物的降解。研究结果表明，共混体系中加入适量的AlCl3催化剂后，分散相尺寸减小，分布均匀，储能模量增加，低频区的复数黏度升高。但AlCl3用量过高时使共混物的分散相尺寸增加，分布均匀度下降，储能模量和复数黏度降低。以GPC为手段研究了单组分 Lewis酸AlCl3对共混组分的降解作用，发现对PS的降解作用显著。 由于单组分Lewis酸催化剂会导致共混组分降解，使共混体系的物理机械性能变劣，为此，我们在LLDPE/PS共混物中引入了双组分Lewis酸催化剂（Me3SiCl、InCl3•4H2O）。结果表明双组分Lewis酸催化剂不但能够催化LLDPE和PS的原位接枝反应，获得高性能的LLDPE/PS合金材料，而且不会引发共混组分PS的降解。在催化剂用量固定时，采用双组分催化剂时共混物的拉伸强度随着LLDPE含量的增加几乎保持不变，但冲击强度有十分明显的提高。对比了加入催化剂前后共混物形貌的变化，增容后的共混物中分散相粒子尺寸显著降低，证明了双Lewis酸良好的催化性能。 对以双Lewis酸为催化剂的共混物的流变行为和结晶行为进行了研究。随着催化剂的加入，两相之间的相互作用增强，因此共混物的复数黏度，储能模量和损耗模量都有不同程度的提高。增容后的LLDPE相区变小，因而在冷却过程中出现不同程度的分步结晶现象。 对单组分和双组分Lewis酸催化剂原位反应增容LLDPE/PS共混体系的机理进行了探讨。机理为Friedel-Crafts烷基化反应。在采用单组分Lewis酸催化剂时， AlCl3与体系中含有的微量水等杂质发生反应，形成一个复合物，然后进一步与聚乙烯中的不饱和的双键发生反应形成碳正离子，并攻击LLDPE分子链从而形成大分子的碳正离子LLDPE+，而这些LLDPE+则通过电子的重排而发生剪切断裂。在催化剂的存在下，这些断裂的LLDPE片断取代PS中的苯环上的质子而发生接枝反应，从而形成LLDPE-g-PS共聚物。采用双组分Lewis酸催化剂时，首先发生双Lewis酸的耦合；耦合后的Lewis酸与水等杂质反应生成复合物，然后与非饱和的LLDPE分子反应生成初级碳正离子；初级碳正离子进攻LLDPE主链，生成较大的碳正离子；LLDPE+碳正离子取代PS苯环对位的质子而生成接枝共聚物。

官能化LLDPE及其合金材料(LLDPE/HIPS)的制备及结构性能研究

本文采用核磁共振碳谱、电喷雾质谱研究LLDPE-g-AA接枝产物的链结构。电喷雾质谱显示所有的丙烯酸单体都发生自聚形成低聚物，核磁共振碳谱进一步证明了丙烯酸在聚乙烯链上形成支链，并且由于反应挤出过程中的高温作用，丙烯酸支链脱水形成酸酐。丙烯酸支链在聚乙烯的结晶过程中影响链段的规整性排列，并有可能充当成核剂，使得聚乙烯晶体随着接枝率的升高变得小而不规整。接枝产物的流变行为表明丙烯酸支链起到内增塑剂作用，降低接枝产物的表观粘度，有利于产物的后加工处理。由于接枝率低的缘故，我们采用角鲨烷模拟乙丙共聚物与马来酸酐进行接枝反应。在170℃，单体浓度为2%W/V，引发剂浓度为0.2%W/V下，体系中存在马来酸酐自聚和接枝一对竞争反应。但由于存在链转移，马来酸酐大部分以单个分子形式接在角鲨烷上。对于LLDPE/HIPS共混体系，我们采用不同于以外加增容剂的办法，直接在共混过程中加入路易斯酸，利用聚乙烯本身带有或降解过程中生成的少量双键与苯发生Friedel-Crafts烷基化反应。为了找到最佳反应条件，我们研究了不同AlCl_3含量、反应时间、反应温度对增容效果的影响。增容共混物的力学性能，特别是冲击强度和微观形态照片表明加入AlCl_3后，在PE/HIPS两相界面处生成接枝共聚物PE-g-HIPS，降低界面张力，改善共混性。由于增容剂只在两相界面处生成，因此加入AlCl_3对共混物中聚乙烯组分的热学性能和结晶性并没有太大影响。

线性低密度聚乙烯和聚苯乙烯共混物的原位增容

采用反应挤出的方法，通过使用Friedel-Crofts反应，以AICl3为催化剂对原位增容线性低密度聚乙烯（LLDPE）和聚苯乙烯（PS）共混体系的反应机理、接枝物结构、材料的结构一性能关系、共混物的相分布形态以及多重结晶行为进行了深入研究。使用激光拉曼光谱研究了以AICl3作为LLDPE/PS共混体系的Friedel-Crafts反应的催化剂生成的接枝物的结构，通过对一系列模型化合物结构的分析，确定了发生接枝反应的点应为聚苯乙烯苯环上次甲基的对位。对于增容后共混物的力学性能进行了分析，并找出有效提高力学性能的工艺。根据测定，增容后的LLDPE/PS（80／20）共混物的Izod冲击性能从80J／m提高到了400）／m以上。断裂伸长率从350％提高到了800％以上。相对应的共混物的相分布形态也得到了极大的改善。这种力学性能上的提高，使得LLDPE／PS共混物真正具有了使用价值及商业前景。这也是研究LLDPE/PS共混物主要目的之一。随着含量AICl3的增加，共混物中PS分散相粒子的尺寸逐渐减小，直至共混物的相分布形态由原来的分散相一连续相结构变为双连续结构。这种形态上的改变，正是力学性能提高的基础。添加过量的AlCl3会对共混物产生一定的降解作用。通过GPC和MER等手段的分析，发现这种降解作用对于共混物中的 PS组分更加明显，而且这种降解只发生在接枝反应之后，与接枝反应是一对竞争的反应。研究了增容后的LLDP／PS（20／80）共混物的熔融结晶行为，发现了这个共混物具有复杂的多重结晶行为。通过对共混物界面层的SEM和TEM观察分析发现：在共混物的LLDPE和PS两相的中间，具有一层由LLDPE-g-PS接枝共聚物形成的界面层。这个界面层中的LLDPE链段与LLDPE均聚物在熔体中紧密的缠结着。当共混体系从较高的熔融温度逐渐下降的时候，接枝共聚物会因为链段之间的相互作用而在熔体下就形成相分离。在接枝共聚物的有序化过程中，与之紧密缠结的LLDPE均聚物分子也会随着有序化的过程而进入相分离所形成的微域结构中。研究了共棍物的这种多重结晶行为。根据共聚物的特性，首次采用了对共混物进行熔点温度之上的高温退火来研究有序一无序转变对共混物多重结晶行为的影响。由于在两相界面层的LLDPE-g-PS接枝共聚物有序化所形成的大量的微域结构限制了处于其中的LLDPE分子的结晶，导致这部分LLDPE分子结晶所需的过冷程度增加，最终只能采用均相成核的方式结晶所致。研究发现，在不同的熔融温度、退火温度以及退火时间都会对共混物的这种受限结晶行为产生很大的影响。在低于接枝共聚物的有序一无序转化温度下退火时，受限于接枝物形成的微域结构中的LLDPE均聚物分子会在这个过程中从微域结构中脱离，重新进入更大的LLDPE分散相粒子中。如果退火的温度高于接枝共聚物的有序一无序转化温度，那么这些LLDPE均聚物分子仍然会在降温的时候被“吞入”有序化所形成的微域结构中而无法脱离这种受限环境。

具有环氧化酶-2选择性抑制活性的多取代蒽醌的合成

1-甲基-2-甲氧羰基-3, 6, 8-三羟基-7-甲氧基蒽醌是从唐菖蒲干球茎中分离到的具有环氧化酶-2选择性抑制活性的多取代蒽醌类化合物。本文试图合成该化合物，实现了其类似物的合成，同时发现了几个未见报道的反应。 1．通过Diels-Alder 反应合成了关键中间体——3-甲基-5-羟基-1, 2, 4-苯三甲酸三甲酯，1-COOMe选择性水解产物与1, 2, 3-三甲氧基苯进行分子间Friedel-Crafts反应的产物再进行分子内Friedel-Crafts反应得到了目标产物的类似物1-甲基-2-甲氧羰基-3-羟基-6，7，8-三甲氧基蒽醌（路线1）。目标产物及其它类似物的合成正在进行中。 2．以乙酰乙酸甲酯和巴豆醛为原料，经过Michael加成、分子内的Aldol反应、芳香化、选择性甲酰化和还原反应，得到关键中间体2-甲基-3-羟甲基-6-甲氧基苯甲酸甲酯及其衍生物。通过该化合物与3，4，5-三甲氧基苯甲酸甲酯进行Friedel-Crafts烷基化反应得到了多取代的二苯基甲烷衍生物，拟进一步关环合成目标化合物（路线2）。 3．发现邻甲氧基苯甲酸甲酯中酯甲基可以被正丁基锂和仲丁基锂中烷基交换生成相应的酯，反应的机理不明确。当使用叔丁基锂时，得到的是邻甲氧基苯基叔丁酮，这个方法可以用来合成芳基叔丁酮类化合物。 4．以2-苄氧基-6-甲基苯甲酸甲酯为原料进行氯甲基化反应时，以苯和二氯乙烷作溶剂，发生了苄基的迁移和芳环的偶联，分别得到2，2'-二甲基-3，3'-二甲氧羰基-4，4'-二羟基联苯和2，2'-二甲基-3，3'-二甲氧羰基-4，4'-二羟基-5，5'-二苄基联苯。这是对称联苯合成的新方法。 5．水杨酸羟基邻对位的选择性甲酰化可以分别通过水杨酸和水杨酸甲酯用HMTA/CF3COOH来实现。 6．Lewis酸催化3，4，5-三甲氧基苄醇环化成1, 2, 3, 6, 7, 8, 11, 12, 13-nonamethoxyl-10,15-dihydro-5H-trbibenzo [a, d, g] cyclononene (NDTC)，产率(54%)高于已有方法（12%）。 Methyl 3,6,8-trihydroxy-7-methoxy-1-methylanthraquinone-2-carboxylate is a new COX-2 selective inhibitor isolated from Gladiolus gandavensis. Two strategies were investigated to synthesis this compound, in which some important reactions were discovered. 1. The key intermediate 5-hydroxy-3-methylbenzene-1,2,4-tricarboxylic acid 2,4-dimethyl ester was prepared via Diels-Alder reaction followed by selective hydrolysis of 1-COOMe. This compound was coupled with 1,2,3-trimethoxybenzene and the product undergo intramolecular Friedel-Crafts reaction to give methyl 3-hydroxy-5,6,7-trimethoxy-1-methylanthraquinone-2-carboxylate (1st route). The target compound and other analogues are being prepared with the same procedure. 2. The key intermediates methyl 3-hydroxymethyl-6-methoxy-2-methylbenzoate and its derivatives were prepared starting from crotonaldehyde and methyl acetoacetate via Michael addition, intramolecular aldol reaction, aromatization, formylation and reduction. The intermediates were coupled respectively with derivatives of gallic acid to give polysubstituted diphenylmethane. However, attempts to cyclize these compounds to the target compounds and analogues were not successful (2nd route). 3. In the process for ortho-lithiation of methyl 2-methoxybenzoate, the substrate converted respectively to n-butyl 2-methoxybenzoate and sec-butyl 2-methoxybenzoate when n-BuLi and sec-BuLi were used. However, tert-BuLi reacted with methyl 2-methoxybenzoate afford 2-methoxyphenyl tert-butyl ketone, which could be used to synthesize aryl tert-butyl ketones. 4. The transformtion of methyl 2-benzoxy-6-methylbenzoate to dimethyl 4,4'-dihydroxy-2,2'-dimethylbiphenyl-3,3'-dicarboxylate in benzene, and dimethyl 5,5'-dibenzyl-4,4'-dihydroxy-2,2'-dimethylbiphenyl-3,3'-dicarboxylate in 1,2-dichloroethane in the presence of ZnCl2 provides a new method for the synthesis of symmetric biphenyl. 5. The formylation of salicylic acid at C-5 and methyl 2-hydroxybenzoate at C-3 could be regioselectively realized by using HMTA/CF3COOH. 6. Racemic 1, 2, 3, 6, 7, 8, 11, 12, 13-nonamethoxyl-10, 15-dihydro-5H-trbibenzo [a, d, g] cyclononene was prepared via Lewis acids catalyzed trimerization of 3, 4, 5-trimethoxylbenzyl alcohol with yield (54%) higher than the reported procesure (12%).

天然产物Standishinal 的首次全合成研究

具有1，1，4α-三甲基氢化芴骨架结构的天然三环二萜化合物自然界中不常见。在该类化合物中，Standishinal 具有良好的芳香化酶抑制活性和细胞毒活性。迄今未发现有Standishinal 的全合成报道，因此，我们对Standishinal 的全合成进行了探索，在该过程中得到以下实验结果： 1. 发现MSA/P2O5、MSA 在无溶剂条件下，25 °C 时烷氧基苯即可实现向苯酚的转化，但在CH3NO2 中，温度升高至80 °C 并未发生反应。 2. 烷氧基苯或对溴苯酚与α-环香叶酸在不同温度下以MSA/P2O5、MSA、PPA为催化剂以CH3NO2 为溶剂或以BF3·Et2O为催化剂时均不发生Friedel-Crafts酰化反应。 3. 对溴苯酚与香叶酸在p-TsOH 催化作用下发生了香叶酸向α-环香叶酸环化、α-环香叶酸环与对溴苯酚的酯化，得到了唯一产物α-环香叶酸对溴苯酯，产率68%。 Standishinal is one of tricyclic-diterpenes possessing the uncommon 1, 1,4a-trimethylhydrofluorene skeleton. Standishinal possesses cytotoxic and aromataseinhibitory activities. Till now, no synthesis of standishinal has been reported. Inattempt to synthesize standishinal, the following phenomenon were observed: 1. Alkyloxybenzenes could be transformed into corresponding phenol at 25 °C inthe presence of MSA/P2O5 or MSA under solvent free condition. ButAlkyloxybenzenes are stable in presence of MSA/P2O5 or MSA in CH3NO2 even at 80 °C. 2. Friedel-Crafts acylation of alkyloxybenzenes and p-bromophenol withα-cyclogeranic acid could not be realized under catalysis of MSA/P2O5, MSA or PPAin CH3NO2, or under catalysis of BF3·Et2O without CH3NO2. 3. The reaction of 4-bromaophenol and geranic acid in the presecnce of p-TsOHafforded 4-bromophenol α-cyclogeranoate in which cyclization of geranic acid toα-cyclogeranic acid was followed by esterification of α-cyclogeranic acid with p-bromophenol.

Reactive compatibilization of LLDPE/PS blends with a new type of Lewis acid as catalyst

The reactive compatibilization of LLDPE/PS (50/50 wt%) was achieved by Friedel-Crafts alkylation reaction with a combined Lewis acids (Me3SiCl and InCl3 center dot 4H(2)O) as catalyst. The graft copolymer at the interface was characterized by Fourier transform infrared spectroscopy and the morphology of the blends was analysized by scanning electron microscopy. It was found that the combined Lewis acids had catalytic effect on Friedel-Crafts alkylation reaction between LLDPE and PS, and the catalytic effect was maximal when the molar ratio of InCl3 center dot 4H(2)O to Me3SiCl was 1:5. The graft copolymer LLDPE-g-PS was formed via the F-C reaction and worked as a tailor-made compatibilizer to reduce the interfacial tension. The mechanical properties of reactive blend with combined Lewis acids as catalyst was notably improved compared to that of physical LLDPE/PS blend and serious degradation had been decreased compared to the reactive blend system with AlCl3 as catalyst; we interpreted the above results in term of acidity of combined Lewis acids.

Rheology, morphology and mechanical properties of LLDPE/PS blends catalyzed by combined Lewis acids

The rheological, morphological and mechanical properties of LLDPE/PS blends with a combined catalyst, Me3SiCl and InCl3 center dot 4H(2)O, were studied in this work. The higher complex viscosity and storage modulus at low frequency were ascribed to the presence of graft copolymers, which were in situ formed during the mixing process. From the rheological experiments, the complex viscosity and storage modulus of reactive blends were higher than the physical blends. The dispersion of LLDPE particles of reactive blending becomes finer than that of physical blends, consistent with the rheological results. As a result of increased compatibility between LLDPE/PS, the mechanical properties of reactive blends show much higher tensile and Izod impact strength than those of physical blends.

A Facile and Practical One-Pot Synthesis of beta-Oxo Thioamides from beta-Oxo Amides and Isothiocyanates

A facile and practical one-pot synthesis of beta-oxo thioamides from beta-oxo amides has been developed. By treatment with isothiocyanates in ethanol in the presence of potassium carbonate, a series of beta-oxo amides was converted, under reflux, in high yields into the corresponding beta-oxo thioamides.

PEG-supported dipyridyl ligand for palladium-catalyzed Suzuki and Suzuki-type reactions in PEG and aqueous media

An air- and water-stable PEG-supported bidentate nitrogen ligand is prepared and its applications in the palladium-catalyzed Suzuki reaction of aryl halides with arylboronic acids in PEG and Suzuki-type reaction of aryl halides with sodium tetraphenylborate in aqueous media are reported. The homogeneous catalyst system is environmentally friendly and offers the advantages of high activity, reusability and easy separation.