Production of (5R,6S)-6-acetoxy-5-hexadecanolide, the mosquito oviposition pheromone, from the seed oil of the summer cypress plant, Kochia scoparia (Chenopodiaceae).

The oviposition pheromone for the pathogen-vectoring mosquitoes in the genus Culex (Diptera: Culicidae), that is, (5R, 6S)-6-acetoxy-5-hexadecanolide, is efficiently synthesized, in admixture with the inactive (5S,6R) enantiomer ( approximately 33% w/w), from the fixed oil extracted from the seeds of the summer cypress plant, Kochia scoparia (Chenopodiaceae), cultivated on an industrial scale. Oviposition bioassays using gravid females of Culex quinquefasciatus, a vector of filariasis in human beings, showed that the product was attractive, with activity comparable to that of a pure synthetic sample containing the same amount of the active enantiomer. Production of the pheromone in the form of a biologically active crude material via a cheap and renewable plant suitable for development as a new industrial crop provides the basis for control of Cx. quinquefasciatus and other congeneric vectors of pathogens in resource-poor areas of the world.     

Agronomic evaluation of phosphorus fertilizers developed from sokoto rock phosphate in Nigeria

Abstract

Sokoto rock phosphate (SRP) obtained from Sokoto in the Northern Nigeria was evaluated with some other phosphorus (P) sources viz: Partially acidulated rock phosphate (PARP) and single superphosphate (SSP) in the greenhouse and field studies. These fertilizers were also compared with nitrogen‐phosphorus‐potassium (NPK) 11–12–11–9.7S‐1.4Zn and NPK 10–20–5–6.5S which have 80% of their P as rock phosphate and were formulated through compaction. The fertilizers were applied in the greenhouse at 0–400 mg kg^‐1soil on the Oyo Arenic Haplustalf and Alagba Kandiudult soil. Field trials were carried out at four locations—at Ikenne in the humid, Samara in the subhumid, Gumi and Gusau in the semi‐arid zones of Nigeria. The fertilizers were applied at 0–150 kg P₂O₅ ha^‐1 in the humid zone and 0–100 kg P₂O₅ ha^‐1in the subhumid and semi‐arid zones. Maize was used as test crop in most sites except at Samaru where sorghum was planted. The results of the greenhouse study showed that on the Haplustalf, PARP, and NPK 10–20–5–6.5S gave almost a similar relative agronomic effectiveness (RAE about 70%) as SSP, which was followed by SRP and NPK 11–12–11–9.7S‐1.4Zn (RAE between 50 and 60%). On the Kandiudult, the RAE of the fertilizers increased significantly. The PARP and NPK 10–20–5–6.55S gave high effectiveness (RAE about 90%) relative to SSP. The field trials results indicated that ground SRP was suitable for direct application on slightly acid soil in the humid zone (annual rainfall > 1,200 mm). Its efficiency was fairly moderate in the subhumid and quite low in the semi‐arid zones (annual rainfall <900 mm). The PARP gave higher RAE than SRP and had almost similar efficiency as for NPK 10–20–5–6.5S. The PARP was well comparable to SSP in the humid and subhumid zones and was fairly comparable to the later in the semi‐arid. This suggests that PARP may be suitable for humid and subhumid zones and the physical quality was also superior to SRP and SSP. Application of SRP on soils in the semi‐arid zones of low rainfall gave relatively low yields which could be due to inadequate moisture availability required to enhance P solubilization.     

Evaluation of phosphorus availability from three phosphorus sources in Nigerian soils

Abstract

In an attempt to search for a cheaper source of phosphorus (P), both for direct application and industrial use, three P fertilizers were evaluated in incubation and greenhouse studies. Indigenous Sokoto rock phosphate (SRP) imported, Togo rock phosphate (TRP), and conventional single superphosphate (SSP) were applied on three soil types namely Oxisol, Ultisol, and Alfisol at rates ranging from 0–800 mg P kg^‐1 soil. Evaluation of the P sources was conducted for 12 weeks in incubation study, and five weeks in the greenhouse using maize as test crop. Evaluation of direct application of SSP and SRP on an oxic paleudult was carried out in the field for three years. The results of incubation studies revealed in general, that P availability increased as fertilizer rates increased. The P availability was, however, greater when SSP was applied on the Alfisol than on the Oxisol and Ultisol. The rock phosphates on the other hand were more efficient on acid soils than on soils neutral in pH. Optimum P availability from the fertilizers was observed to occur predominantly between four and eight weeks of incubation. In the greenhouse study, SSP gave the highest cumulative P uptake and optimum rate of application was 200 mg P kg^‐1 soil, while optimum rate for rock phosphate was 400 mg P kg^‐1 soil. The agronomic effectiveness (EA) of the rock phosphates was about 40% relative to SSP on the Alfisol. The EA, however, for TRP and SRP was 120% and 160%, respectively, on the Oxisol, while on the Ultisol, SRP was equally effective as SSP and TRP had 65% effectiveness. The results of the field trial indicated that the SRP had 54%, 83%, and 107% agronomic effectiveness of SSP, respectively, in the first, second, and third year of cropping. Optimum rate for SSP and SRP application was considered to be 50 and 75 kg P₂O₅ ha^‐1, respectively.     

Synthesis of haptens and development of an immunoassay for the olive fruit fly pheromone

An enzyme-linked immunosorbent assay (ELISA) for the olive fruit fly pheromone, Bactrocera oleae Gmelin, was developed. The assay uses polyclonal antibodies, raised in rabbits, against (+/-)-beta-[3-(1,7-dioxaspiro[5.5]undecane)]propionic acid, 2 (hapten I), conjugated to the KLH (keyhole limpet hemocyanin) by the carbodiimide method. A second hapten, (+/-)-delta-[3-(1,7-dioxaspiro[5.5]undecane)]butylamine, 3 (hapten II), after conjugation to a biotin moiety, was used for indirect immobilization onto ELISA microwells precoated with the glycoprotein avidin. The developed ELISA method measures the synthetic olive fruit fly pheromone in concentrations ranging between 0.08 and 10 microg/mL and shows great promise for practical applications for pheromone detection in environmental and biological samples. The results obtained strongly indicate that this technique, to our knowledge the first insect pheromone enzyme-linked immunosorbent assay so far reported, is a fast, sensitive, inexpensive, and highly convenient method for the analysis of a volatile and low molecular weight compound such as 1,7-dioxaspiro[5.5]undecane, 1.     

Ovipositional responses of the pulse beetle, Bruchus chinensis (Coleoptera: Bruchidae) to extracts and compounds of Capparis decidua

Extracts of Capparis decidua stems and flowers showed insecticidal and oviposition inhibitory activities against Bruchus chinensis. The LC50 values of these extracts were found to increase with the increase in the polarity of the extract at different exposure periods. For instance, after 96 h, the LC50 values were found to be 3.619, 7.319, and 10.151 microg for CD1, CD2, and CD3, respectively. Extract CD7 was effective only at higher doses. The toxicity was found to be dose- and time-dependent. The females laid lesser number of eggs, when exposed to sublethal doses of different extracts and pure compounds, as compared to control. The maximum oviposition deterrence index was found for extract CD1 followed in decreasing order by CD2, CD3, and CD7. From extract CD1, two compounds were isolated and characterized as triacontanol (C1) and 2-carboxy-1,1-dimethylpyrrolidine (C2). When the females were exposed to sublethal doses of these compounds, they laid lesser number of eggs as compared to the control. C2 was found to have a slightly greater oviposition inhibition effect than C1. From fraction CD7, one novel compound labeled as CDF1 has been isolated and identified as 6-(1-hydroxy-non-3-enyl)tetrahydropyran-2-one. CDF1 has also shown insecticidal and oviposition inhibitory activities against B. chinensis at low concentrations.     

Variations of Phosphorus Release from Sediments in Stratified Lakes

The aim of this investigation was to study the temporal variation in phosphorus release from the sediments and its influence on water quality of stratified lakes. The concentrations of soluble reactive phosphorus (SRP), calcium and sulfate in the interstitial water and the pH in the wet sediments of dimictic lakes were investigated during the spring circulation and at the end of summer stratification. Multiple regression analysis using the calculated diffusive fluxes of SRP out of the sediments and the morphometric characteristics of the lakes (reduced water depth), explained 73 % of the variance of the SRP-accumulation in the hypolimnia during summer stagnation. At the end of surnmer stratification diffusive fluxes of SRP out of the sediments increased and pH-values and sulfate-concentrations decreased at the sediment surface (0–2 em) and in the hypolimnia. The maximum diffusive flux of SRP was calculated to be 5.8 mg/m²/d at the end of summer stagnation. Prob able reasons for these higher diffusive fluxes of SRP at the end of summer stagnation are higher supply of labile organic matter and thereby higher mineralization rates. lower redox potential and thus higher dissolution of redox sensitive P-binding forms and/or dissolution of phosphorus being bound to Ca-phases at lower pH.     

Increased predicted losses of phosphorus to surface waters from soils with high Olsen-P concentrations

Abstract. Diffuse soluble reactive P (SRP) & total P (TP) loads from over 50 major river catchments in Northern Ireland were predicted using an export coefficient modelling approach. Phosphorus export coefficients for each CORINE land cover class, derived from satellite imagery, allowed the prediction of P loads from a breakdown of the CORINE land cover classes by catchment using a GIS. This approach was validated using observed P loads calculated from flow and concentration data. Mean measured Olsen-P concentrations in the soil A-horizon were also determined on a catchment basis. Plots of P loads to the watercourse versus Olsen-P concentrations in the soil showed a breakpoint around 22 mg Olsen- P l⁻¹ for both SRP & TP data. Below Olsen-P concentrations of 22 mg l⁻¹, SRP & TP losses were essentially independent of Olsen-P at 0.28 and 0.63 kg P ha⁻¹ yr⁻¹, respectively. Above Olsen-P concentrations of 22 mg l⁻¹, there was considerable spread in the P loss data. Nevertheless, significant upward trends in SRP and TP losses to watercourses were detected with increasing Olsen-P at a rate of approximately 0.5 and 1.0 kg P ha⁻¹ yr⁻¹, for SRP and TP respectively, for each 10 mg l⁻¹ increase in Olsen-P.     

辐照亚洲玉米螟F-1雄虫在田间的扩散能力和对性诱剂的反应能力

用亚洲玉米螟性诱剂田间诱捕释放的１００Ｇｙ、１５０Ｇｙ和２００Ｇｙ辐照的Ｆ１雄虫和正常雄虫。试验表明,部分辐照的Ｆ１雄虫丧失了飞翔扩散能力或对性诱剂的反应能力,但在距释放点５５０ｍ处诱捕到的Ｆ１雄蛾数与诱捕总数之比与正常雄蛾无显著差异。     

Comparative Effect of Phosphorus Sources for Grain Amaranth Production

Abstract

Phosphorus (P) is expensive to the sub‐Saharan African resource‐poor farmers; therefore, there is a need for investigation of locally available alternative P sources to enhance farmers' productivity. Optimum P rate was determined during the early and late rains of 1999. Using the optimum P rate, influences of three P sources ogun rock phosphate (ORP), sokoto rock phosphate (SRP), single super phosphate (SSP) and a control were evaluated on amaranth varieties in 2000 at the vegetable research plots of the National Horticultural Research Institute (NIHORT), Ibadan, Nigeria. In 1999, three grain amaranth varieties (NH84/452, NH84/445, and NH84/493) were combined factorially with four P rates: 0, 30, 60, and 90 kgP/ha. Application of P significantly increased plant height, number of branches, leaf dry weight, and grain yield (GY) per plant. Significant increase in GY was in the order NH/493>NH/445>NH/452. Optimum P rates across varieties for leaf dry‐matter yield was established at 51.8 kgP/ha and for grain yield production was 48.4 kgP/ha. The experiment in the following year, 2000, was a RCB design using the optimum P determined in 1999. Three P sources (ORP, SRP, SSP) and a control were factorially combined with the three amaranth varieties. In the 2000 experiment, grain yield was 21.3, 16.9, 16.0, and 7.8 g/plant, respectively, for SSP, SRP, ORP, and the control. Growth was ranked in the order SSP>ORP>SRP>control. It was concluded for fertilizer recommendation purposes that 50 kgP/ha is optimum for grain amaranth production and that amaranth productivity indices could be alternatively improved with indigenous P sources.     

Factors Regulating the Flux of Phosphate at the Sediment - Water Interface of a Subtropical Calcareous Lake: a Simulation Study with Intact Sediment Cores

Different factors which interactively control the flux of soluble reactive phosphorus (SRP) at the sediment water irterface (SWI) of Lake Kinneret were studied seasonally. The influence of pH, Eh and microbial activity on SRP flux at the SWI was investigated by manipulating the conditions in the overlying water of intact sediment cores. The calculated diffusive SRP flux out of the sediment was lower in cores sampled during winter and spring than during the period of amixis. Potential SRP release, as measured in the absence of microbial activity, was strongly enhanced upon the transition from oxic to anoxic conditions indicating P release from iron(III)-bound phosphorus. In spring and summer cores, an enhanced SRP flux from sediments at pH 7 in comparison to pH 8 indicated P release from carbonate-bound P which sedimented previously as result of high pH values during the algal spring bloom. Microbial uptake at the SWI was the most important sink for SRP and no net-flux occured under oxic conditions. The higher net-flux of P under anoxic conditions was linked to carbon limitation ofthe bacteria at the SWI.     

Fe(III)-EDDHA and -EDDHMA sorption on Ca-montmorillonite, ferrihydrite, and peat.

The effectiveness of Fe chelates as Fe sources and carriers in soil can be severely limited by the adsorption of Fe chelates or chelating agents in the solid phase. To study this phenomenon, well-characterized peat, Ca-montmorillonite, and ferrihydrite were used as model compounds, and the adsorption of Fe-EDDHA and Fe-EDDHMA chelates were studied. Sorption isotherms for the meso and racemic isomers of these chelates on the soil materials are described. The variability of sorption with pH in peat and ferrihydrite was also determined because both have variable surface charge at different pH values. In montmorillonite, at low concentrations, the retention of Fe from the Fe-EDDHMA chelate is greater than the one of the Fe-EDDHA chelate. As well as the concentration increased, the inverse situation occurs. The behavior of both meso and racemic isomers of chelates in contact with Ca-montmorillonite is similar. The Fe-meso-EDDHA isomer was highly adsorbed on ferrihydrite, but the racemic isomer is not significantly retained by this oxide. For Fe-EDDHMA isomers, the racemic isomer was more retained by the oxide, but a small sorption of the racemic isomer was also observed. Results suggest that Fe-EDDHA chelates were more retained in peat than Fe-EDDHMA chelates. The most retained isomer of Fe-EDDHA was the meso isomer. For Fe-EDDHMA, the adsorption was very low for both racemic and meso isomers.     

直播方式对水稻生理性状和产量的影响及其成本分析

为探讨水稻不同直播方式对产量和生理特性以及成本的影响,该文设置了旱直播、水直播和机条播3种直播方式,研究了水稻的产量表现、群体发育、生理特征以及经济效益。结果表明,与旱直播相比,机条播和水直播的产量分别增加了11.9%和6.3%,氮肥农学利用率分别增加了10.1%和4.9%。从产量构成因素分析,产量的提高主要得益于单位面积穗数的增多。机条播显著提高了茎蘖成穗率、花后与成熟期干物质积累量、生长中后期的茎蘖数、叶面积指数与持续期、群体生长速率、叶片光合速率和根系氧化力。机条播因其机械作业效率高、费用低以及除草成本低使得总成本降低和经济效益提高,说明机条播方式提高了直播水稻叶片光合性能,并促进了地上部群体合理生长和地下部根系活力,从而获得了较高的产量和经济效益。     

Reduction of Carpophilus freemani dobson (Coleoptera: nitidulidae) aggregation pheromone response by synthetic analogues.

Analogues of (2E,4E,6E)-5-ethyl-3-methyl-2,4,6-nonatriene, the major component of the aggregation pheromone of Carpophilus freemani Dobson (Coleoptera: Nitidulidae), were synthesized and the potency of these compounds in suppressing the response of C. freemani to its pheromone in a wind tunnel bioassay was determined. The most potent compounds reduced behavioral response to pheromone 83-96% when the inhibitors were present in 10-fold excess. These compounds are (1Z, 3E,5E)-1-methoxy-3-ethyl-5-methyl-1,3,5-heptatriene, (1E,3E, 5E)-1-cyclopropyl-3-ethyl-5-methyl-1,3,5-heptatriene, and (1Z,3E, 5E)-1-cyclopropyl-3-ethyl-5-methyl-1,3,5-heptatriene. In the presence of fermenting bread dough (a pheromone synergist), the most potent inhibitory compound, (1Z,3E, 5E)-1-cyclopropyl-3-ethyl-5-methyl-1,3,5-heptatriene, was less effective in reducing mean landings (69% vs 99%) than when dough was absent. This inhibitory compound causes a reduction of response to pheromone but does not cause a reduction of response to fermenting food-type volatiles such as fermenting bread dough. Analogues of pheromones that strongly reduce response to pheromones by insects might be useful as biochemical probes to study the pharmacophoric (three-dimensional structure) requirements for pheromone perception.     

Antagonism of pheromone response of Ostrinia nubilalis males and implications on behavior in the laboratory and in the field

The antagonistic effect on the pheromone response and catabolism of male European corn borers, Ostrinia nubilalis, by several trifluoromethyl ketones is reported. (Z)-11-Tetradecenyl trifluoromethyl ketone (Z11-14:TFMK), the most closely related analogue of the main component of the pheromone, elicits a remarkable disruptive effect on close approach and source contact of males flying to a source baited with mixtures of the pheromone and the antagonist in 5:1 and 10:1 ratios. In this experiment, the male displayed an erratic flight track with frequent counter turns and intersections with the plume. In the field, the TFMK significantly lowered the number of males caught when mixed with the pheromone in a 10:1 ratio in comparison with the natural attractant. The compound was also a good inhibitor of the antennal esterase of the insect with a IC(50) value of 0.28 muM. The homologous (Z)-10-tridecenyl trifluoromethyl ketone, with one carbon less in the chain, also elicited an antagonistic effect in the wind tunnel, but in the field, the results were not conclusive. The effect induced was lower than the one displayed by Z11-14:TFMK including the activity as the esterase inhibitor (IC(50) value of 7.55 muM). The saturated tetradecyl trifluoromethyl ketone, tetradecyltrifluoropyruvamide, and (Z)-11-2-thiatetradecenyl trifluoromethyl ketone resulted completely inactive. The results obtained in conjunction to the previously shown low toxicity to mice by related trifluoromethyl ketones provide new important data for the putative utilization of these chemicals as new pest control agents.     

Response of benthic soluble reactive phosphorus transfer rates to step changes in flow velocity

Purpose

The purpose of this study was to investigate the responses of the benthic soluble reactive phosphorus (SRP) transfer rate to step changes in the flow velocity of the overlying water using laboratory experiments and a non-steady-state numerical model.

Materials and methods

Laboratory experiments were conducted using a rectangular recirculating flume. After pre-incubation of sediments in a cavity of the experimental flume for 2?days, the step responses of the SRP transfer rate to sudden increases in the flow velocity were examined under anaerobic conditions. The benthic SRP transfer rates were obtained from the rate of increase in the SRP concentration of the overlying water. We also analysed the response using a newly constructed numerical model that consists of a one-dimensional diffusion model of the diffusive boundary layer (DBL) and a biochemical model of the sediment, in which oxygen, SRP, ferrous iron and nitrate were model variables. The non-steady-state calculation was performed to reproduce the experiments after the step change in the flow velocity.

Results and discussion

The experiments revealed a rapid increase in the SRP concentration in the overlying water that continued for approximately 5?min after the step change in flow velocity and was followed by a lower, steady increase in the SRP concentration. The model analyses also demonstrated that a step increase in flow velocity leads to a drastic enhancement of the SRP transfer rate within a few minutes. The abrupt increase in the transfer rate was due to the rapid transport of SRP that had accumulated in the DBL and to enhanced diffusion caused by a temporal increase in the SRP concentration gradient in the DBL. The modelled results for the SRP transfer rate were in agreement with the experimental results.

Conclusions

The temporal increase in SRP transfer was due to rapid SRP transport caused by intensified diffusion following a decrease in DBL thickness. The model-based results for the response of the SRP transfer rate were in agreement with the experimental results. Therefore, our model can simulate the response of the SRP concentration profile near the sediment?Cwater interface to temporal variations in flow velocity.     

不同类型海水养殖水体温度日变化谐波分析

利用谐波方法对宁波地区2010-2013年代表性海水养殖水体(池塘和养殖海湾)在不同天气情况下(晴、少云、多云、阴)水温的日变化特征进行模拟,探究养殖水体温度的日变化规律。结果显示:(1)池塘和养殖海湾水温日变化的最佳谐波模拟阶数分别为2阶和3阶,2阶(3阶)谐波对池塘(养殖海湾)水温逐小时、日最高和日最低值模拟的绝对误差分别为0.24~0.31℃(0.1~0.15℃)、0.2~0.24℃(0.06~0.1℃)和0.11~0.15℃(0.06~0.08℃);(2)谐波模拟误差整体呈白天大夜间小,对阴天水温变化趋势的模拟效果较其它天气条件差;(3)池塘水温遵循以24h和12h为周期的日变化规律,其中24h周期比重最高,养殖海湾遵循以12h、24h和6h为周期的日变化规律,其中12h和24h比重较6h高,晴到多云天气条件下12h和24h周期比重相当,阴天24h周期比重明显下降。本研究论证了谐波方法对不同天气条件下池塘和养殖海湾水温日变化特征模拟的可行性,并定量评估了养殖水体日变化的周期特征,可为海水养殖水体温度精细化预报提供参考依据。     

十溴联苯醚对秀丽隐杆线虫毒性研究

十溴联苯醚(BDE-209)是一类新型持久性有机污染物,可导致神经系统和生殖发育等多种生理毒性。本文以秀丽隐杆线虫(Caenorhabditis elegans)为模式生物,通过分析十溴联苯醚(BDE-209)对其繁殖、寿命、细胞凋亡以及体内超氧化物歧化酶基因sod-3、类p-53蛋白基因cep-1、细胞色素P450基因cyp35a2以及谷胱甘肽转移酶基因gst-1的影响,来评价BDE-209的生理、细胞及分子水平毒性。试验结果表明,与空白对照相比,BDE-209低剂量(5 mg kg-1)短时间暴露,对秀丽线虫细胞凋亡及产卵影响不显著;高浓度长时间暴露(30 mg kg-1)会导致秀丽隐杆线虫产卵数目下降,寿命缩短,细胞凋亡。Real-time PCR试验表明,低剂量(5 mg kg-1)暴露使得sod-3、cep-1、cyp35a2基因表达显著增加;高剂量暴露(30 mg kg-1),虽然sod-3表达显著增加,但增加幅度低于低浓度暴露组,cep-1、cyp35a2基因表达显著受到抑制。说明长期暴露在高浓度(30 mg kg-1)十溴联苯醚环境中,会促使秀丽隐杆线虫产生氧化应激反应,秀丽隐杆线虫通过调控相关抗氧化基因的表达来修复这种损伤,而高浓度的BDE-209会造成其机体氧化损伤、细胞凋亡及产卵量下降。     

Phosphorus export from a paddy rice field during flood events

Abstract. A field plot experiment was conducted to investigate P mobilization from fertilized rice fields during rainfall-flooding events. The experiment tested the effects of inorganic fertilizer P, at two rates, and P fertilizer plus manure, at one rate, on the amounts of P lost in drainage water when the plots were subjected to four artificially simulated storm-flooding/drainage events over an eight day period. During the first drainage event, two days after P application, the concentrations and loads of soluble reactive P (SRP) and particulate P (PP) in the drainage water were some three to five times lower than they had been just 24 hours earlier due to rapid sorption and sedimentation. At subsequent events, the concentrations and loads of SRP in drainage water were almost two orders of magnitude lower than at the first event, i.e. the equilibrium between P release from fertilizer and manure and P sorption/fixation by the soil mineral fraction had shifted strongly in favour of the latter processes. During the first drainage event, the concentrations and loads of SRP in drainage water from the low P fertilizer treatment were similar to those on the low P fertilizer plus manure treatment, whereas, 24 hours earlier they had been significantly greater. At subsequent events, though, the highest concentrations and loads of SRP occurred in drainage water from plots treated with equal amounts of P fertilizer and manure. It is suggested that extending the time period between P application and flooding events by applying fertilizer and manure outside the main rainy season should significantly reduce the risk of P loss from paddy rice fields.     

虾夷扇贝海上转运系统改进设计与试验

针对目前虾夷扇贝(Patinopecten yessoensis)海上转运系统作业装备落后及作业方式不合理,致使作业效率低、用工人数多、以及扇贝缩边死亡与碎贝现象严重等问题,通过对獐子岛虾夷扇贝海上转运系统的调研,提出了一种转运方案,并对转运装备进行优化设计。通过海上生产对比试验,得出以下结论:为虾夷扇贝采捕船配备甲板拣贝作业系统与可折叠式装贝笼箱,优化了采捕船拣贝、装箱、装卸舱等作业模式,使劳动强度大幅降低,且用工人数减少2人/艘,作业时间缩短了约0.6 h;运输船采用可折叠式装贝笼箱代替原转运笼箱,使笼箱装卸流程更加合理高效,且作业时间缩短了约0.52 h;采用改造后虾夷扇贝转运系统运输,扇贝缩边死亡率与碎贝率显著降低,其中扇贝平均缩边死亡率约为1.92%,且5个月试验扇贝缩边死亡率无显著差异(P0.05),与原转运系统相比显著降低(P0.05),降低了约1.43%;改造后平均碎贝率约为0.84%,且5个月试验碎贝率无显著差异(P0.05),较原转运系统显著降低(P0.05),降低了约1.99%;改造后的虾夷扇贝海上转运系统经济效果显著,每年可节省费用约2 853.6万元。由此说明,改造后的虾夷扇贝海上转运系统具有高效、高收益等特点,推广应用前景广阔。     

基于模块化设计的水利水保工程桩基钢筋笼加工平台研究

[目的]针对在水利、水保及民用建筑工程领域的基础工程施工中所用到的钢筋笼加工制作平台存在的造价高,使用不便,制作材料浪费大,标准不统一和加工质量差等问题,基于"系统化、模块化"的设计思想,设计一种钢筋笼加工制作平台。[方法]该设计主要包括固定支架模块和固定轴模块。固定架模块由一对固定支架组成;固定轴模块由高笼模块、中笼模块和低笼模块组成。内固定轴模块通过内滚动轴承连接外固定轴模块,外固定轴模块表面沿外圆周安装有数个主筋镶片,主筋镶片上有横向的主筋卡槽和纵向的加强箍或支撑箍卡槽。[结果]该设计解决了不同桩基设计要求的钢筋笼尺寸制作不通用问题,也解决了钢筋笼加工不统一、不标准,且一个工程一台机械,用完即丢弃的问题。不仅能使成品钢筋笼加工质量容易符合规范要求,而且能防止在制作过程由于就地制作造成的泥土和油污对笼身的污染,大大提高了制作和施工效率,节约成本,保护了环境。[结论]桩基钢筋笼加工平台的改进设计对不同类型基础工程中设备器材的可持续利用有重要意义,它可以促进建筑材料的循环应用。