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Mesh regulations of bottom trawl for the protection of economic immature fishes off southwestern TaiwanHuang, Meng-Hsun 09 September 2008 (has links)
The present research adopts with the application of the sequential mesh regulations on bottom trawl to study how to protect economic immature fishes. The experimental design includes first the determination of the relationships of fish size and the price per weight (PPW) of the economic demersal fishes sold as the one-hundred Dollars-a-plate manner in Tunkang and Zihguan fish markets in the southwestern coast of Taiwan. The obtained results were used to yield the catch of smaller size fishes and the lower PPW for regulating the economic immature fishes. The three kinds of regulated fish size were defined as the smallest surveyed size, smallest economic size, and smallest matured size. These regulated fish size were used as the body lengths of 50% selection (L50) to calculate the regulating mesh size.
This study presents that four steps are needed for the sequential mesh regulations of bottom trawl in the southwestern Taiwan. The first step is to regulate the mesh size between 35 and 45 mm for banning bottom trawler to catch fishes smaller than the smallest surveyed fish size. The objective of first step is to reduce the bycatch without affecting the landings of economic immature fishes sold in the fish market. The second step is to regulate the mesh size between 50 and 60 mm for banning bottom trawler catch fishes smaller than the smallest economic fish size, and to reduce the catch of smaller size fishes and the lower PPW of economic immature fishes. The third step is to regulate the mesh size between 65 and 70 mm for banning bottom trawler to catch fishes smaller than the smallest matured fish size. This is also to reduce the catch of economic immature fishes, and to increase the recruitment. The fourth step is to regulate the mesh size between 70 and 82 mm for banning bottom trawler catching the lower PPW of economic fishes that is not large enough to reach their optimal PPW.
The present research provides important data results for regulating the mesh size of bottom trawler operation for the achievement of sustainable coastal fishery in Taiwan.
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Investigation of Soldier Crabs, Mictyris brevidactylus, as a Biomonitor for Heavy Metal ContaminationYeh, Hiao-Chien 12 February 2009 (has links)
This study is the first attempt to investigate heavy metal concentrations in the soldier crab
with a view to it being a potential candidate for the monitoring of copper(Cu), zinc(Zn),
nickel(Ni), lead(Pb) and cadmium(Cd) levels on the western coast of Taiwan. The objectives
of this investigation included the following: (1) to assess the pollution status at different sites
by determining the metal concentrations of ambient water and Pacific oysters; (2) to monitor
the concentrations of heavy metals, including Cu, Zn, Ni, Pb and Cd, in the soldier crab; (3) to
assess the effect of sex, wet weight and reproductive season at different sites¡F(4) to
investigate the distribution of metal concentration among carapace, gonads, midgut gland,
muscle; and (5). to assess the pollution status at different sites and years by monitoring the
concentration of heavy metals, including Cu, Zn, Pb and Cd in male soldier crabs
The Pacific oyster and stream results proved that site B is contaminated by Cu, Zn and Pb
from streams B-1 and B-2. The highest Cu, Zn, Ni and Pb concentrations in soldier crabs
appeared at site B, and significant differences in the accumulated concentrations of Cu, Pb, Zn
and Ni in soldier crabs were found between the sites tested. The highest bioconcentration
factors of Cu, Zn, Ni and Pb in soldier crabs appeared at site B, indicating that the soldier crab
can accumulate Cu, Zn and Pb to the same degree as the Pacific oyster. In fact, soldier crabs
can accumulate more Ni than Pacific oysters, better reflecting the conditions of the ambient
environment. These phenomena, as well as the fact that the soldier crab is able to accumulate
relatively high levels of Cu, Zn, Pb and Ni, suggest that this crab is a potential biomonitor of
Pb and Ni pollution in aquatic ecosystems.
Only in the case at site A of Pb sex related difference could be detected. In general mean Pb
level in male soldier crabs were higher than in female. There are no significant sex related
differences of Cu, Zn, Cd and Ni in soldier crab among three sites. The lead mean
concentration in reproduction season and pre- reproduction season were higher than
non-reproduction seasons. The highest concentrations of lead were found in carapace and the
gonad in reproduction season.
The results presented that the metal concentration in soldier crabs vary significantly not
only because of season change in polluted sites, but also it may be influenced by the
sex-related and size-related difference of organisms. After eliminating size effect, sex effect
by analyzing 0.7 g~ 1.0 g and male soldier crabs to monitor the pollution status, the Cu and
Zn concentrations in soldier crabs along the Changhua coastline(site A and site B) is stable¡F
The higher concentrations of Pb and Cd in soldier crabs existed in 2002 and 2003. We suggested that the polluted sources of Pb and Cd along the Changhua coastline in 2002 is abundant, and of Pb contents from 2003 to 2006 and Cd content from 2003 to 2007 are decreasing. Therefore, it is essential to take size effect, sex, season, and polluted status into
account in comparative biomonitoring studies using soldier crabs as metals biomonitor. The
baseline concentration of soldier crabs were 21.4 £gg g-1 wet wt. Cu, 20.1 £gg g-1 wet wt. Zn, 0.13 £gg g-1 wet wt. Pb, 0.12 £gg g-1 wet wt. and 0.91 £gg g-1 wet wt..
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Manufacturihng of heavy rings and large copper canisters by plastic deformationSsemakula, Hamzah January 2003 (has links)
<p>Plastic deformation processes transform material fromas-received state to products meeting certain requirements inproperties, microstructure and shape. To achieve thistransformation, the relationship between material response andprocess conditions should be understood. This is usuallycomplicated by the complex conditions describing the actualprocess. Numerous techniques including empirical, physical,analytical and numerical can be employed.</p><p>In this thesis, numerical technique supported by lab- andfull-scale experiments has been employed to analyse the formingparameters. The first part of the thesis is focused on the useof such parameters to predict occurrence of material poresduring manufacturing of bearing rings. The second part dealswith the influence of forming parameters on the grain sizeduring fabrication of large copper canisters for encapsulationof nuclear waste. The primary task has been to study with thehelp of commercial FE-codes the magnitude and distribution offorming parameters such as accumulated effective strain,temperature, instantaneous hydrostatic pressure and materialflow at different stages of the forming process. In the firstpart, two types of ring manufacturing routes, which result inpore free and pore loaded rings are studied and compared.Material elements located in different areas of the workpiecehave been traced throughout the process. Results of theaccumulated strain and instant hydrostatic pressure have beenanalysed and presented in pressure-strain space. Itsassumed that high hydrostatic pressures together with higheffective strains are favourable for pore closure. Area of theworkpiece with unfavourable parameters have been identified andcompared with ultrasonic test results. Good agreement has beenobtained. Based on the results of this analysis, a new conceptfor avoiding pores in manufacturing of yet heavier rings hasbeen presented. The concept proposes a lighter upsetting in theinitial stage of the process and a more efficient piercingwhich results in higher hydrostatic pressure and bigger andbetter distributed effective strain.</p><p>In the second part of the thesis, the influence of formingparameters such as effective strain and temperature on thefinal grain size of the product has been studied in laboratoryscale. As-cast billets of cylindrical shape were extruded atdifferent temperatures and reductions. It has been shown thatthe grain size in the final product should be small in order toenable ultrasonic tests and to guarantee resistance towardscreep and corrosion. Simulations for different materialelements located at different distances from the axis ofsymmetry of the initial cylindrical workpiece have been carriedout. In this way, the parameters describing the deformationhistory of the elements have been determined as functions oftime. Experimentally obtained pre- and post deformation grainsize in the corresponding locations of the material weredetermined. Its concluded that low temperature coupledwith high effective strain are conducive for obtaining a smallgrain size. Based on the beneficial conditions for extrusion ofcopper, a more detailed FE-analysis of a full-scale industrialprocess is carried out. A coarse-grained cast ingot of purecopper is heated and by upset forging formed into a cylinder,which is then punched into a hollow blank for subsequentextrusion. The blank is extruded over a mandrel through a45-degree semi-angle die. Accumulated effective strain andtemperatureas functions of the tubular wall thickness havebeen studied at five different locations along the tubularaxis. Forming load requirement as function of tool displacementfor each stage of the process has been determined. Strain andtemperature levels obtained have been related to the grain sizeinterval obtained in the earlier work. It has been concludedthat the levels reached are within the interval that ensures asmall grain size. A similar analysis has been carried out forforging of large copper lids and bottoms. Die designmodifications to improve the grain size in the lid and tooptimise the forging process with respect to forging load andmaterial yield have been proposed. A method requiring a smallforging load for fabrication of the lids has been analysed</p><p><b>Keywords:</b><i>Pores; grain size; low forging load; effective strain;temperature; hydrostatic pressure; extrusion; forging;canister; lid; rings</i></p>
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Thermophoretic force measurements of spherical and non-spherical particles /Zheng, Feng, January 2000 (has links)
Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 111-116).
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Project SHAPE : an experimental evaluation of a group versus computer-based intervention to improve food portion size estimation skills /Ayala, Guadalupe Xochitl. January 2002 (has links)
Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2002. / Vita. Includes bibliographical references (leaves 242-255).
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Preemptive power analysis for the consulting statistician novel applications of internal pilot design and information based monitoring systems /Sawrie, David Franklin. January 2007 (has links) (PDF)
Thesis (Ph.D.)--University of Alabama at Birmingham, 2007. / Title from PDF title page (viewed on Feb. 19, 2010). Includes bibliographical references.
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A microfluidic Coulter counting device for metal wear detection in lubrication oilVeeravalli Murali, Srinidhi. January 2008 (has links)
Thesis (M.S.)--University of Akron, Dept. of Mechanical Engineering, 2008. / "December, 2008." Title from electronic thesis title page (viewed 12/9/2009) Advisor, Jiang John Zhe; Faculty Readers, Joan Carletta, Dane Quinn; Department Chair, Celal Batur; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
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Self-designing optimal group sequential clinical trials /Thach, Chau Thuy. January 2000 (has links)
Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 107-111).
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Utvärdering av regnmätning och droppstorleksfördelning från en distrometer / Evaluation of Rain Measurement and Drop Size Distribution from a DisdrometerWennerdahl, Emelie January 2015 (has links)
Nederbördsmätning är viktigt inom många områden och en relativt ny teknik är enoptisk distrometer som med hjälp av laserteknik mäter nederbördspartiklarnasdroppstorlek och fallhastighet. Syftet med detta arbete var att undersöka hur välThies distrometer stämmer överens med nederbördsmätning från ett vippkärl ochmanuella mätningar från institutionen för geovetenskaper vid Uppsala universitet.Institutionen för geovetenskaper överväger att gå över till denna teknik och därmedbehövdes distrometern utvärderas för olika faktorer som kan påverka instrumentet.Vid jämförelse mellan instrumenten visade det sig att distrometern totalt sett samladein mer nederbörd än de andra mätarna. Det är svårt att avgöra vad skillnaden mellaninstrumenten kan bero på men felkällor så som avdunstning och vätning hos vippkärletoch manuella mätningar kan ge mindre nederbörd. En annan orsak kan varafelkalibrering av datan från distrometern. Inga samband hittades för vindhastighet,vindriktning och typ av nederbörd mellan de tre instrumenten. En vidare undersökning gjordes för droppstorleksfördelningen för att ge exempelpå fördelar med en distrometer. Droppstorleksfördelningen från distrometernjämfördes med exponentialfördelningen framtagen av Marshall & Palmer (1948).Resultatet visade sig stämma överens med tidigare studier, fördelningen stämmerbra överens för stratiforma väder, men sämre för konvektiva och snö. / Measuring precipitation is important in many areas of research. A relatively newtechnology for measuring precipitation is the optical disdrometer, which measures thefalling velocity and drop size of particles by using lasers. The purpose of this workwas to compare data from a disdrometer with data from a tipping bucket and amanual measurement series from the Department of Earth Sciences at UppsalaUniversity. The comparison between the instruments showed that the disdrometermeasured more precipitation than the tipping bucket and the manual measurements.A reason for this can be due to evaporation and wetting from the tipping bucket andmanual measurement. Errors in calibration of data from the disdrometer may alsohave influence. Furthermore, an analysis of the drop size distribution was done in order todetermine areas of special use for the device. The drop size distribution calculatedfrom the distrometer was compared with the Marshall and Palmer (1948) distribution.The results showed that the MP-distribution was a good fit for stratiform weather;however, for convective clouds and snow the fit was not satisfactory and some otherrelationship should be used instead.
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Effects of sediment supply and slope on channel topographic roughness and sediment transportAronovitz, Alexander Craig 20 July 2012 (has links)
We investigate evolution of mountain channel morphology and riverbed surface roughness by conducting laboratory experiments. The experimental flume is 4m long by 0.1m wide with a working length of 2.5m. We control initial sediment size distribution, flume slope, water discharge, and sediment feed rate. Measurements include topographic profiles, flow depth, surficial grain-size distribution, sediment transport rate, and sediment size distribution. Experiments begin with a gravel bed of a broad sediment size distribution, at two initial flume slopes: 8.2% and 12.4%. Discharge is held constant until transport rates and topographic changes indicate the system is at near steady state. Coarse sand is then fed into the channel at 1,000 g/min as a means to perturb the system. Sediment feed is held constant until the perturbed bed reach steady-state conditions. The feed is subsequently ceased and measurements continue until sediment transport rates and topography stabilize.
These laboratory experiments provide first-hand observations of channel systems evolving after perturbations. Transport rates decay exponentially following perturbations and remain very low when the channel bed is stabilized. The introduction of coarse sand acts to smooth the channel bed by filling in topographic lows in the 8.2% sloped channel. At a 12.4% slope, increased mobility of sand allows steady state conditions to be met with little smoothing of the bed. The sand also increases the mobility of coarser sediment that was previously stable, likely due to local surface smoothing at grain scale. The increased fraction of surface sand cover maintains increased scouring and mobilization of coarser grains. These post-perturbation mechanisms are interpreted to be responsible for topographic adjustments as the system readjusts towards new steady-state conditions. Surface sorting and transporting distributions reflect high sand fractions well after perturbations have ceased. This suggests that brief pulses of fine sediment can increase coarse sediment mobility for prolonged periods. / text
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