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Optimising mesh size with escape gaps in a dual-species portunid-trap fishery

Aquaculture and Fisheries 2020年第6期5卷 308-316页

作者： Matt K.Broadhurst Daniel J.Tolhurst Brian Hughes Vincent Raoult Timothy M.Smith Troy F.Gaston NSW Department of Primary Industries Fisheries Conservation Technology UnitNational Marine Science CentrePO Box 4321Coffs HarbourNSW2450Australia Marine and Estuarine Ecology Unit School of Biological SciencesUniversity of QueenslandBrisbaneQLD4072Australia The Roslin Institute and Royal(Dick)School of Veterinary Studies University of EdinburghEaster BushMidlothianEH259RGUnited Kingdom Hunter Local Land Services PO Box 440TareeNSW2430Australia School of Environmental and Life Sciences University of NewcastleOurimbahNSW2258Australia

In south-eastern Australia,the same baited,round traps(comprising 50–57-mm mesh netting)are used to target giant mud,Scylla serrata and blue swimmer crabs,Portunus armatus in spatially separated *** fisheries are characterised by the common,problematic discarding of undersized portunids(mesh(91 mm to match the minimum legal size of the smaller ***),and then(2)any cumulative benefits of fitting species-specific escape *** experiment 1,there were no differences among catches of legal-sized portunids associated with either partial,or complete trap coverage with larger *** of mesh coverage,both designs of 91-mm traps also retained significantly fewer(by up to 42%)undersized *** and *** experiment 2,replicate traps completely covered in 91-mm mesh were tested against conventional traps comprising 56-mm mesh,and traps with the same mesh sizes,but also three escape gaps configured for either ***(46×120 mm)or ***(36×120 mm)(*** treatments in total).All modified traps maintained catches of legal-sized ***,and only the 91-mm traps with escape gaps caught fewer legal-sized *** undersized ***,*** and ***(mean catches reduced by up to 49%)were retained in all larger-meshed than small-meshed traps,and in all of those traps with escape gaps(by up to 95%)than *** there were no significant cumulative benefits of escape gaps in largermeshed traps(measured by a statistical interaction),there was a trend of fewer unwanted catches *** data support configuring portunid traps with mesh sizes matching the morphology of the smallest legal-sized target ***,simply retroactively fitting escape gaps in existing,smaller-m

关键词： Bycatch Escape gap mesh size Portunid

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Target Dimension and mesh size Dependency for Numerical Simulation on Jet Penetration into Semi-infinite Target

Target Dimension and Mesh Size Dependency for Numerical Simu...

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2005国际机械工程与力学会议

作者： Yu ZHENG Xiaoming WANG Wenbin LI COSTIND Key Subject Laboratory School of Mechanial Engineering Nanjing University of Science and Technology

When simulating the phenomenon of jet penetrating into semi-infinite target, we face two problems. The first one is how to choose a proper dimension of the target model which can stand for the real semi-infinite target, and the second one is how to decide the mesh size. By using the non-linear dynamics analysis software AUTODYN-2D, an example of jet vertically penetrating into semi-infinite target was simulated to study the influence of mesh size and target dimension to the penetration results. The relationship between the jet parameters and the critical dimension of the finite element model of target was gained. The effects of different mesh sizes on the penetration depth, aperture and calculation time were investigated After analyzing the simulation results a proper range of mesh size was obtained. The simulation results could provide design reference for setting up models of jet penetrating into semi-infinite target.

关键词： Penetration Semi-infinite target Jet Numerical simulation Target dimension mesh size

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Simulation methodology development for rotating blade containment analysis

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第4期13卷 239-259页

作者： Qing HE Hai-jun XUAN Lian-fang LIAO Wei-rong HONG Rong-ren WU High-Speed Rotating Machinery Laboratory Institute of Chemical MachineryZhejiang UniversityHangzhou 310027China Department of Automation Zhejiang UniversityHangzhou 310027China

An experimental and numerical investigation on the aeroengine blade/case containment analysis is presented. Blade out containment capability analysis is an essential step in the new aeroengine design, but containment tests are time-consuming and incur significant costs; thus, developing a short-period and low-cost numerical method is warranted. Using explicit nonlinear dynamic finite element analysis software, the present study numerically investigated the high-speed impact process for simulated blade containment tests which were carried out on high-speed spin testing facility. A number of simulations were conducted using finite element models with different mesh sizes and different values of both the contact penalty factor and the friction coefficient. Detailed comparisons between the experimental and numerical results reveal that the mesh size and the friction coefficient have a considerable impact on the results produced. It is shown that a finer mesh will predict lower containment capability of the case, which is closer to the test data. A larger value of the friction coefficient also predicts lower containment capability. However, the contact penalty factor has little effect on the simulation results if it is large enough to avoid false penetration.

关键词： Aeroengine Blade containment Simulation methodology mesh size Contact penalty factor Friction coefficient

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Advanced biomedical hydrogels:molecular architecture and its impact on medical applications

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Regenerative Biomaterials 2021年第6期8卷 297-317页

作者： Jonathan T.Peters Marissa E.Wechsler Nicholas A.Peppas McKetta Department of Chemical Engineering The University of Texas at AustinAustin200 E.Dean KeetonAustinTX 78712USA Institute for Biomaterials Drug Deliveryand Regenerative MedicineThe University of Texas at Austin107 W.Dean KeetonAustinTX 78712USA Department of Biomedical Engineering and Chemical Engineering The University of Texas at San AntonioOne UTSA CircleSan AntonioTX78249USA Department of Biomedical Engineering The University of Texas at Austin107 W.Dean KeetonAustinTX 78712USA Division of Molecular Pharmaceutics and Drug Delivery College of PharmacyThe University of Texas at Austin107 W.Dean KeetonAustinTX 78712USA Department of Surgery and Perioperative Care and Department of PediatricsDell Medical SchoolThe University of Texas at Austin1601 Trinity St.Bldg.BAustinTX 78712USA

Hydrogels are cross-linked polymeric networks swollen in water,physiological aqueous solutions or biological *** are synthesized by a wide range of polymerization methods that allow for the introduction of linear and branched units with specific molecular *** addition,they can be tuned to exhibit desirable chemical characteristics including hydrophilicity or *** synthesized hydrogels can be anionic,cationic,or amphiphilic and can contain multifunctional crosslinks,junctions or tie *** these characteristics,hydrogels exhibit compatibility with biological systems,and can be synthesized to render systems that swell or collapse in response to external *** versatility and compatibility have led to better understanding of how the hydrogel’s molecular architecture will affect their physicochemical,mechanical and biological *** present a critical summary of the main methods to synthesize hydrogels,which define their architecture,and advanced structural characteristics for macromolecular/biological applications.

关键词： hydrogels networks mesh size hydrogel reactions biological applications biomedical applications

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Litter decomposition in pure and mixed Quercus and Fagus stands as influenced by arthropods in Belgrad Forest,Turkey

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Journal of Forestry Research 2020年第4期31卷 1123-1137页

作者： Meric Caklr Ender Makineci Department of Soil Science and Ecology Faculty of ForestryCanklrl Karatekin University18100 CanklrlTurkey Department of Soil Science and Ecology Faculty of ForestryIstanbul University-Cerrahpasa34473 Sariyer/IstanbulTurkey

Arthropod assemblages and decomposition rates were compared in the litter of pure and mixed Quercus(Quercus petraea L.)and Fagus(Fagus orientalis L.)*** was sampled on a monthly basis for 1 year and stored in litterbags of different mesh *** experimental objective was to test the effect of mesh size on litter decomposition,decomposition rates of litter,and diversity of the invertebrate fauna between the two types of *** rates were measured by filling three fiber litterbags of different mesh sizes with pure Quercus litter(3 g)left in the pure Quercus stand,and litterbags with Fagus litter(3 g)were left in the pure Fagus *** litter samples were prepared by mixing of equal amounts of each litter in the same litterbag and leaving them in the mixed *** residual mass of litter from the pure Quercus stand was significantly lower in fine-and coarse-mesh bags than in the medium-mesh bags in pure the Fagus *** and nitrogen levels in the pure Quercus litter were significantly different among the mesh sizes at the end of the incubation *** from 27 taxa were collected from pitfall traps every *** relative numbers differed significantly between the pure and mixed-stand litter ***-dwelling Isotomidae(Collembola)and Mesostigmata(Acarina),and soil-dwelling Mesostigmata were the most numerous in the mixed *** is significant that the abundance of macroarthropods contributed to the mass loss of litter in both the medium and coarse mesh sizes in the mixed stand,but did not significantly affect the mass of litter in the pure *** the mixed stand,there was a negative correlation between litter mass loss and total number of microarthropods in all mesh ***-stand litter decomposed more slowly than pure-stand litter.

关键词： Collembola(springtails) mesh size Pitfall trap RDA Quercus Fagus litter decay

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A review on fishing gear in China: Selectivity and application

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Aquaculture and Fisheries 2022年第4期7卷 345-358页

作者： Zhongqiu Wang Hao Tang Liuxiong Xu Jian Zhang East China Sea Fisheries Research Institute Chinese Academy of Fishery AcademyShanghai200090China College of Marine Sciences Shanghai Ocean UniversityShanghai201306China National Engineering Research Center for Oceanic Fisheries Shanghai201306China Key Laboratory of Oceanic Fisheries Exploration Ministry of Agriculture and Rural AffairsShanghai201306China The Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources Shanghai Ocean UniversityMinistry of EducationShanghai201306China Center for Polar Research Shanghai Ocean UniversityShanghai201306China

In the 1980s,China’s offshore marine fishery resources declined,thus fishing gear selectivity gradually became a focus of scientific fishery *** of fishing gear selectivity mainly focus on five kinds of fishing gear:trawls,shrimp beam trawls,stow nets,gillnets,and *** net method is the main method used in the comparative study of codend selectivity of both trawls and stow *** results showed that(1)Bottom trawls,targeting Larimichthys polyactis(the Little yellow croaker)and Trichiurus haumela(the Hairtail),should have a minimum mesh size of the codend no less than 60 mm in the Yellow and East China *** the codend should use a square mesh with a minimum mesh size of 40 mm due to the variety of targeted species in the South China Sea.(2)Pair pelagic trawls,targeting pelagic species such as Engraulis japonicus(the Japanese anchovy),Pampus argenteus(the Silvery pomfret),Scomberomorus niphonius(the Spanish mackerel),as well as bottom species such as *** and ***,should have a minimum mesh size of the codend no less than 56 mm in the Yellow Sea.(3)Shrimp beam trawls should use shrimp/fish separator devices(e.g.,separator panels,vertical separator panels,and sorting grids)to improve intra-species selectivity and reduce by-catch of non-target fish.(4)Canvas stow nets,targeting *** and ***,should have a minimum mesh size of the codend no less than 55 mm.(5)Gillnets,the minimum mesh size should be determined for catching traditional economic species,but also the optimal mesh size for newly developed *** as,gillnets with mesh size of 35-38.71 mm targeting Harpodon nehereus(the Bombay duck),55 mm targeting *** and Nemipterus virgatus(the Golden threadfin bream),72 mm targeting Dentex tumifrons(the yellow sea breams)or Scomberomorus commersoni with body length of 280 mm,100 mm targeting ***,104 mm or 146 mm targeting 2-3 year or 6-7 year ***,120 mm targeting *** with body length

关键词： Trawl mesh size Shrimp/fish separator Stow net Gillnet

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