Academic literature on the topic 'Catch-rate'
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Journal articles on the topic "Catch-rate"
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Hjerne, Olle, and Sture Hansson. "Constant catch or constant harvest rate?" Fisheries Research 53, no. 1 (September 2001): 57–70. http://dx.doi.org/10.1016/s0165-7836(00)00266-6.
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Hoenig, John M., Cynthia M. Jones, Kenneth H. Pollock, Douglas S. Robson, and David L. Wade. "Calculation of Catch Rate and Total Catch in Roving Surveys of Anglers." Biometrics 53, no. 1 (March 1997): 306. http://dx.doi.org/10.2307/2533116.
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Widodo, Agustinus Anung, and Mahiswara Mahiswara. "CATCH RATE AND CATCH COMPOSITION OF FISH TRAWL BASED IN SIBOLGA, NORTH SUMATERA." Indonesian Fisheries Research Journal 17, no. 2 (February 9, 2017): 63. http://dx.doi.org/10.15578/ifrj.17.2.2011.63-73.
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To obtain data and information of fish trawl fishery performance operated in the Indian Ocean, a research was carried out through observation on board by observers as well as port sampling inSibolga Fishing Port by enumerators in September 2007, with the aimed to study the performance fish trawl fishery. These include fleet structure, trawl net design and construction, catch, fishing trip, fishing ground, and fishing operation. Results of research showed that there were 71 registered fish trawlers in Sibolga Fishing Port and only 25 boats active due to increasing of fuel price. The fleet structure of fish trawler consist of boat with size 31-114 GT which can be classified into 3 categories i.e. small(<60 GT), medium (60-150 GT), and large fish trawler (>150 GT). Design and construction of fish trawl net indicated that fish trawl net operates in the Indian Ocean was high opening trawl with head and ground rope of 27.8-41.5 m and 29,7-45.8 m, respectively. Fishing trip generally 10-12 days with effective days 7-9 days per trip and the number of net setting was 5-6 times each day. The fishing grounds of fish trawl based in Sibolga were the coastal waters area with maximum depth of 91 m. At least 40 species of fishes and shrimps identified during research and dominant fish species was ponyfish (Leiognathus spp.) threadfin bream (Nemipterus spp.), tall fin goatfish (Upeneus spp.), seacatfish (Arius sp.) as well as yellow striped goatfish (Upeneus vitattus). The average of catch of fish trawler fleet in the year of 2007 was 249.3 kg/haul and that number seems smaller than average of catch/haul previous years. This situation indicates that decreasing of catch per haul of fish trawlers based in Sibolga continues occurring and in other hand price of fuel raises significantly so that big fish trawlers size 150 GT with engine power more than 600 HP are not able to continue their fishing operation.
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Anggawangsa, Regi Fiji, Suwarso Suwarso, and Wudianto Wudianto. "CATCH RATE AND CATCH COMPOSITION OF MINI PURSE SEINE IN BUALEMO, BANGGAI DISTRICT." Indonesian Fisheries Research Journal 20, no. 1 (June 1, 2014): 23. http://dx.doi.org/10.15578/ifrj.20.1.2014.23-28.
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Small pelagic fishery is the largest potential commodity in the waters of Tomini Bay which reached 64% of the total fish resources. Mini purse seine (soma pajeko) is the major fishing gear that used to utilize small pelagic resources in Tomini Bay. One of the main fishing grounds of mini purse seine vessels in Tomini Bay is in Bualemo and the surrounding waters. The aim of this research was to describe mini purse seine fishery in Bualemo especially about the aspects of the catch rate and catch composition. From the analysis of the daily catch data, there was a fluctuation of the average of catch rate each month. The catch of mini purse seine in Bualemo was dominated by two main species that is malalugis/mackerel scad (Decapterus macarellus) and bigeye scad (Selar crumenophthalmus). The large amount of the young fish (juvenile) caught by mini purse seine caused by the vessels operated around FADs and the mesh size that was less selective.
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Dauk, Philip C., and Carl J. Schwarz. "Catch Estimation in the Presence of Declining Catch Rate Due to Gear Saturation." Biometrics 57, no. 1 (March 2001): 287–93. http://dx.doi.org/10.1111/j.0006-341x.2001.00287.x.
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Xiao, Yongshun. "Catch equations: calculating the instantaneous rate of fishing mortality from catch and back." Ecological Modelling 193, no. 3-4 (March 2006): 225–52. http://dx.doi.org/10.1016/j.ecolmodel.2005.08.034.
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Monnahan, Cole C., and Ian J. Stewart. "The effect of hook spacing on longline catch rates: Implications for catch rate standardization." Fisheries Research 198 (February 2018): 150–58. http://dx.doi.org/10.1016/j.fishres.2017.10.004.
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Shelton, Peter A. "Did over-reliance on commercial catch rate data precipitate the collapse of northern cod?" ICES Journal of Marine Science 62, no. 6 (January 1, 2005): 1139–49. http://dx.doi.org/10.1016/j.icesjms.2005.04.009.
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Abstract It has been suggested that a number of “lessons” can be learned from the collapse of the northern cod stock off Newfoundland and Labrador. However, not all purported lessons have been validated with available data. One lesson is thought to be that over-reliance on commercial catch rate data and an incorrect assumption regarding the functional relationship between catch rate and population size were major contributors to overestimating stock size, precipitating the collapse. The current study describes calibration approaches used in assessments, and evaluates alternative functional relationships between commercial catch rates and stock size. In addition, historical population size is re-estimated using only research vessel data and compared with estimates obtained based on both commercial catch rate and research vessel data. Calibration with commercial catch rate contributed to overestimating stock size in some years, but there is no evidence that the assumed functional relationship between commercial catch rate and population size was a significant factor in the collapse.
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Rijnsdorp, Adriaan D., Jan Jaap Poos, and Floor J. Quirijns. "Spatial dimension and exploitation dynamics of local fishing grounds by fishers targeting several flatfish species." Canadian Journal of Fisheries and Aquatic Sciences 68, no. 6 (June 2011): 1064–76. http://dx.doi.org/10.1139/f2011-032.
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Patch exploitation dynamics, based on individual tow data, provided new insights into the fishing behavior of mixed fisheries. Fishing grounds were determined and their geometry quantified based on the proximity of tow positions. Tows were classified as being part of either searching, sampling, or exploitation behavior based on the intertow distance. Fishers can detect patches of flatfish on a scale of ∼25 nautical miles2. Catch rate during exploitation was 24%–36% above the catch rate while searching, and decreased at a rate of 20%·day–1. Once a patch was found, exploitation occurred until the catch rate dropped below a threshold level. The optimal giving-up catch rate was estimated based on the observed search time, catch rate decline, and range of fishing ground quality. The observed giving-up catch rate was 6%–11% higher than predicted by the marginal value theorem. The discrepancy between the observed and predicted patch leaving decision was consistent with the bias expected in an individual transferable quota (ITQ) management system. Our results provide a basis for interpreting vessel monitoring system (VMS) data and studying the interaction among fishers and between fishers and their resources at the appropriate time and spatial scale.
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Jatmiko, Irwan, Bram Setyadji, and Rani Ekawaty. "The Effect of Moon Phase on The Catch of Bigeye Tuna (Thunnus obesus) in Eastern Indian Ocean." ILMU KELAUTAN: Indonesian Journal of Marine Sciences 21, no. 3 (August 30, 2016): 101. http://dx.doi.org/10.14710/ik.ijms.21.3.101-106.
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Tuna is one of the important export commodities to increase government income. One of economically important tuna species is bigeye tuna (Thunnus obesus) which has a proportion of 21% of the total production of large tuna group. The objective of this study was to investigate the effects of different moon phase on the catch of bigeye tuna (T. obesus) in Eastern Indian Ocean. Data collection was conducted by the scientific observers from August 2005 to June 2014 in the tuna longline vessels were based in the port of Benoa, Bali. Moon phase data were collected from August 2005 to June 2014 from National Aeronautics and Space Administration (NASA). Catch data were calculated using the catch rate formula which defined as the number of catches per 100 hooks. The number of catch rate then was sorted into each moon phases and were analyzed using one-way Anova. This study covered 62 trips and 1,480 numbers of operations or sets was conducted from sampled vessels. The result showed that the average catch rate of bigeye tuna differed significantly among the moon phases. Tukey post-hoc tests showed that the average catch rate at full moon was the highest among the groups with around 0.3/100 hooks. This study showed that moon phase had significant effect on the catch of bigeye tuna (T. obesus) that increased the catch during full moon. Keywords: moon phase, catch rate, Eastern Indian Ocea, tuna, Thunnus obesus
Dissertations / Theses on the topic "Catch-rate"
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Zhang, Yafei. "Exploring spatial heterogeneity of CPUE year trend and nonstationarity in fisheries stock assessment, an example based on Atlantic Weakfish (Cynoscion regalis)." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/78094.
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Quantitative population dynamics modeling is needed to evaluate the stock status and fisheries management plans to provide robust model and management strategies. Atlantic Weakfish (Cynoscion regalis), one important commercial and recreational fish species along the west coast of Atlantic Ocean that was found to be declining in recent years, was selected as an example species. My study aimed to explore the possible spatial heterogeneity of CPUE (catch per unit effort) year trend based on three fishery independent surveys and explore the influence of nonstationary natural mortality on the fisheries management through a MSE (Management Strategy Evaluation) algorithm based on the Weakfish stock assessment results. Five models for catch rate standardization were constructed based on the NEAMAP (NorthEast Area Monitoring and Assessment Program) survey data and the ‘best' two models were selected based on the ability to capture nonlinearity and spatial autocorrelation. The selected models were then used to fit the other two survey data to compare the CPUE year trend of Weakfish. Obvious differences in distribution pattern of Weakfish along latitude and longitude were detected from these three surveys as well as the CPUE year trend. To test the influence of the model selection on the MSE, five stock-recruitment models and two forms of statistical catch-at-age models were used to evaluate the fishery management strategies. The current biomass-based reference point tends to be high if the true population dynamics have nonstationary natural mortality. A flexible biomass based reference point to match the nonstationary process is recommended for future fisheries management.Master of Science
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Srisurichan, Sukanlaya. "Time series modelling of the environmental factors affecting the daily catch rate of western rock lobster." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2001. https://ro.ecu.edu.au/theses/1511.
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The western rock lobster fishery is one of the most significant and valuable single species fisheries in Australia and in the world. It generates a gross commercial value of $200-300 million dollars per year for the economy of Western Australia. The impact of environmental factors on the daily catch rate of the western rock lobster is of particular interest to the W.A. Marine Research Laboratories, at the Ministry of Fisheries, Western Australia. Considerable time and effort has been invested into building and developing suitable models to measure such impact on this fishery. While past research has focussed on monthly or seasonal data, this study investigated appropriate time series analyses to model the effect of major environmental factors such as lunar cycle, swell, and sea water temperature on the daily catch rate data of the western rock lobster at different depths. The variation in western rock lobster daily catch rate data for two periods ("whites" and "reds") and four categories (undersize, legal size, spawner, and setose ), was examined for three management zones, A, B, and C. Regression and transfer function models for relationships between catch rates and environmental data were considered and compared. Results show that the lunar cycle especially the presence of the full moon and the swell has a significant impact on the daily catch rates of the Western rock lobster. The results of this research assist in the development of improved models to support the management of this very valuable resource.
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Haag, Lucas A. "Effects of spatially variable plant available water on optimal corn seeding rate -- field scale and site-specific approaches." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/818.
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Murray, David Vernon. "The effect of maximal isometric training on doublet-induced force enhancement and its relationship with changes in voluntary rate of force development." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2018. https://ro.ecu.edu.au/theses/2074.
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Motor unit double discharges (i.e. doublets), which are excitatory potentials that occur at shorter-than-normal intervals (e.g. 5-10 ms) during normal muscle activation, are known to cause muscle force to exceed that predicted from a standard, linear summation of twitch forces. However, although a marked increase in the occurrence of motor unit doublets at the onset of a contraction has been observed after explosive-type exercise training, and has been correlated with changes in RFD (Van Cutsem et al., 1998), little is known about the influence of strength training on the physiological and biomechanical benefits derived from the phenomenon. The present research examined the effects of 4 weeks of ‘explosive’ isometric knee extensor strength training on voluntary and electrically-evoked contractile RFD (calculated as the time derivative of the moment-time curve) in 8 untrained male participants. Electrical stimulation (NMES) trains were delivered to the muscle at 20 Hz and 40 Hz and incorporated short (5 and 10 ms) inter-pulse intervals (IPIs) at the onset of stimulation (i.e. variable-frequency trains; VFT). The influence of the short inter-pulse interval was assessed by comparison to a constant frequency train (i.e. the VFT:CFT ratio). Following the training, substantial improvements in maximum isometric knee extensor strength (MVC) (24.3 ± 13.3%, p = 0.002) and RFD measured to time intervals of 50 (55.5 ± 50.3%, p = 0.011), 100 (34.0 ± 47.2%, p = 0.01) and 150 ms (31.9 ± 38.2%, p = 0.02) were observed. RFD normalised to MVC (RFDnorm), measured to time intervals of 50 and 100 ms from the onset of contraction, improved by 44.9 ± 38.8% (p = 0.04) and 13.8 ± 12.2% (p = 0.01), respectively. There was a significant reduction in the VFT:CFT ratio after training when a 10-ms IPI preceded a 20-Hz train when measured to 30 (-13.7 ± 11.3%, p = 0.03), 50 (-13.9 ± 8.4%, p = 0.007), 100 (-8.6 ± 10.2%, p = 0.04), and 200 ms (-8.1 ± 5.3%, p = 0.009) as well as in the interval 100-200 ms (-7.4 ± 6.6%, p = 0.02). However, no significant changes were observed for other stimulation frequency-IPI combinations. Moderate-to-very strong positive correlations were observed between changes in RFDnorm and changes in VFT:CFT when measured within some time periods, particularly in the early phase of the contraction (r = 0.02 – 0.91). In conclusion, the effect of a high-frequency double discharge at stimulation onset remained unchanged or, under some conditions, was reduced after 4 weeks of explosive-type knee extensor training. Additionally, training-dependent improvements in the ability to rapidly reach a specified torque level relative to peak MVC torque (i.e. RFDnorm) were greater for those participants whose VFT:CFT ratio either did not decline or declined the least. These data provide evidence that explosive training may reduce the effect of a high frequency discharge at the onset of a contraction, and that greater increases in RFD may occur in those who most retain this ability.
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Ungewiß, Judith [Verfasser]. "Assessment of vigilance and response quality during static automated perimetry. A study using the method of constant stimuli (MoCS) and an enhanced presentation rate of catch trials / Judith Ungewiß." Tübingen : Universitätsbibliothek Tübingen, 2020. http://d-nb.info/1214639836/34.
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Aidoo, Eric. "Geostatistical modelling of recreational fishing data: A fine-scale spatial analysis." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2016. https://ro.ecu.edu.au/theses/1813.
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The sustainability of recreational fisheries resources rely on effective management of the fishery which includes monitoring of any changes in the fishery. In order to facilitate the ongoing management of the recreational fishery, an understanding of the spatial dynamics of catch per unit effort (catch rate), fishing effort and species diversity is important for fishery managers to make area-specific decisions and to develop strategies for ecosystem based fisheries management. These indices are critical components of information used to inform on recreational fishing activities and evaluate the changes in the fishery resources.
Geostatistical techniques such as kriging can provide useful tools for characterising the spatial distributions of these indices. However, most recreational fishing data are highly skewed, zero-inflated and when expressed as ratios are impacted by the small number problem, which can influence estimates obtained from the traditional kriging. In addition, the use of recreational fishing data obtained through surveys may influence mapping and area-specific decisions as such data are associated with uncertainty.
In Western Australia, recreational fishing has a participation rate of approximately 30%. Data for this thesis were collected from boat-based recreational fishers through phone-diary surveys at spatial resolution that supports spatial analysis and mapping through geostatistical techniques. In this thesis, geostatistical modelling techniques were used to analyse those recreational fishing data in the West Coast Bioregion of Australia, with the development and evaluation of a data transformation approach that takes into account data characteristics and uncertainty. As a first step in the analysis, a suitable kriging estimator for recreational fishing data was determined. This was based on the application of ordinary, ordinary indicator and Poisson kriging estimators for seven aquatic species with different behaviours and distribution patterns. Some of these estimators can handle different distribution properties including high skewness, zero-inflation and small number problems. In general, the indicator kriging performed similarly across species with different life history characteristics and distribution patterns and provided accurate estimates of catch rates for most of those species. To evaluate the incorporation of measurement uncertainty, the study presents a soft indicator kriging approach that uses a logistic function transformation, which is combined with probability field simulation to determine the effect of measurement uncertainty on mapping and fishing area delineation. The results suggest that the incorporation of the measurement uncertainty improves the ability to draw valid conclusions about the estimation results, which may influence any decision regarding the delineation of areas with high catch rates for spatial management. The recreational fishing data used also provided the basis for studying the spatial patterns in species diversity in the entire fishery. The analysis revealed that species diversity, dominance and evenness display similar spatial patterns on a global scale.
The study highlighted the inherent spatial variability in catch rate, fishing effort and species diversity, illustrating areas with high values, or hotspots of these indices. This statistical-based modelling approach is important as it allows prediction of these indices in specific locations taking into account data characteristics and uncertainty. The estimated maps are important for supporting fishery resources management.
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Yu, Hao. "Spatial and temporal population dynamics of yellow perch (Perca flavescens) in Lake Erie." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/28586.
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Yellow perch (Perca flavescens) in Lake Erie support valuable commercial and recreational fisheries critical to the local economy and society. The study of yellow perch's temporal and spatial population dynamics is important for both stock assessment and fisheries management. I explore the spatial and temporal variation of the yellow perch population by analyzing the fishery-independent surveys in Lake Erie. Model-based approaches were developed to estimate the relative abundance index, which reflected the temporal variation of the population. I also used design-based approaches to deal with the situation in which population density varied both spatially and temporally.
I first used model-based approaches to explore the spatial and temporal variation of the yellow perch population and to develop the relative abundance index needed. Generalized linear models (GLM), spatial generalized linear models (s-GLM), and generalized additive models (GAM) were compared by examining the goodness-of-fit, reduction of spatial autocorrelation, and prediction errors from cross-validation. The relationship between yellow perch density distribution and spatial and environmental factors was also studied. I found that GAM showed the best goodness-of-fit shown as AIC and lowest prediction errors but s-GLM resulted in the best reduction of spatial autocorrelation. Both performed better than GLM for yellow perch relative abundance index estimation. I then applied design-based approaches to study the spatial and temporal population dynamics of yellow perch through both practical data analysis and simulation. The currently used approach in Lake Erie is stratified random sampling (StRS). Traditional sampling designs (simple random sampling (SRS) and StRS) and adaptive sampling designs (adaptive two-phase sampling (ATS), adaptive cluster sampling (ACS), and adaptive two-stage sequential sampling (ATSS)) for fishery-independent surveys were compared. From accuracy and precision aspect, ATS performed better than the SRS, StRS, ACS and ATSS for yellow perch fishery-independent survey data in Lake Erie. Model-based approaches were further studied by including geostatistical models. The performance of the GLM and GAM models and geostatistical models (spatial interpolation) were compared when they are used to analyze the temporal and spatial variation of the yellow perch population through a simulation study. This is the first time that these two types of model- based approaches have been compared in fisheries. I found that arithmetic mean (AM) method was only preferred when neither environment factors nor spatial information of sampling locations were available. If the survey can not cover the distribution area of the population due to biased design or lack of sampling locations, GLMs and GAMs are preferable to spatial interpolation (SI). Otherwise, SI is a good alternative model to estimate relative abundance index. SI has rarely been realized in fisheries.
Different models may be recommended for different species/fisheries when we estimate their spatial-temporal dynamics, and also the most appropriate survey designs may be different for different species. However, the criteria and approaches for the comparison of both model-based and design-based approaches will be applied for different species or fisheries.Ph. D.
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Klaer, Neil L., and n/a. "Changes in the structure of demersal fish communities of the South Eastern Australian Ccontinental Shelf from 1915 to 1961." University of Canberra. Resource, Environmental & Heritage Sciences, 2006. http://erl.canberra.edu.au./public/adt-AUC20060804.154133.
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Haul-by-haul steam trawler catch and effort data for 1918�23, 1937�43 and 1952�57,
which covers a large portion of the history of steam trawling in the Australian South
East Fishery, were examined in detail for the first time. There were 64,371 haul records
in total. The catch-rate for all retained catch combined shows a strong decline overall,
with a brief recovery during World War II, probably due to increased retention of
previously discarded species. The fishing fleet moved to more distant fishing grounds
and deeper waters as the catch-rate declined. The catch-rates of the main commercial
species followed a similar pattern in a number of regions within the fishery. The catchrate
of the primary target species � tiger flathead (Neoplatycephalus richardsoni) �
dropped considerably from the early, very high, catch-rates. Chinaman leatherjacket
(Nelusetta ayraudi) and latchet (Pterygotrigla polyommata) � species that were
apparently abundant in the early years of the fishery � virtually disappeared from
catches in later years. The appearance of greater catches of jackass morwong
(Nemadactylus macropterus), redfish (Centroberyx affinis), and shark/skate during the
war and afterwards was probably due to increased retention of catches of these species.
The disappearance of certain species from the catch may be due to high fishing pressure
alone, or to a combination of fishing pressure, changes in the shelf habitat possibly
caused by the trawl gear, and environmental fluctuations.
Catch-rates in weight per haul per species were standardised to annual indices of
abundance using a log-linear model. Standardised annual index trends for flathead,
latchet and leatherjacket indicate a strong to severe decline over the period covered by
the data. All species showed seasonal patterns, but the peak season varied depending on
the species. The distribution of standardised catch-rate by area also differed greatly by
species, and no single area showed consistent differences across all species. Day trawls
caught more flathead, redfish and latchet, while night trawls caught more morwong and
leatherjacket. Moon phase had less influence on catch-rates than the other factors
examined. Correlation of annual index trends with a number of annual mean
environmental factors was examined and no strong correlations were found.
Annual catches of the major commercial trawl species on the SE Australian shelf were
estimated from recorded total trawl catches, catch species composition from subsamples
and estimates of the rate of discarding. These annual catches, standardised
indices of abundance and biological population parameters were used in single-species
stock reduction models to estimate absolute biomass trends. Biological population
parameters and the biomass estimates were used to calculate management reference
point fishing mortality rates F0.1, Fspr30 and Fmsy. Results showed that simple plausible
population models can be constructed that account for catches over the long period of
time from 1915 to 1961.
Simple mass-balance ecosystem models were built for the demersal community of the
SE Australian shelf for 1915 and 1961 using the Ecopath software. Model inputs were
consistent with a more comprehensive SE marine ecosystem model in development by
CSIRO. The models demonstrate that biomass estimates produced by the single species
stock reduction models can be consistently integrated into simple plausible massbalance
ecosystem models.
Modern stock assessments for the main commercial species in this fishery today mostly
used data collected since about 1985. Abundance indices and total catch estimates from
this study have been used in the most recent assessments for tiger flathead and
morwong, allowing construction of the exploitation history for these species spanning
almost 100 years. Use of the historical information has increased confidence in the
estimates of the modern stock assessments � particularly management reference points,
and has allowed us to quantify changes in fish abundance that have simply been
documented anecdotally in the past.
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Lewis, S. J. "Studies in catch-up growth in the rat skeleton." Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382473.
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Vallaud, Thierry. "La rentabilité de la fidélisation du consommateur : 3 essais complémentaires." Thesis, Paris, CNAM, 2013. http://www.theses.fr/2013CNAM0873/document.
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Dans cette thèse sur travaux, l’auteur part de deux travaux précédents sur la rentabilité de la fidélisation et la détermination du potentiel client pour faire un constat : une partie de la rentabilité de la fidélisation et du potentiel pour une marque est basée sur la part captable du chiffre d’affaire fait à la concurrence ; le taux de captation.Dans ce nouveau travail il s’agit de montrer que le taux de captation est basé sur l’élasticité du taux de nourriture. A partir d’une analyse de la littérature et de plusieurs modélisations sur des données de panel scannérisées, l’auteur démontre, sur plusieurs marchés, que l’élasticité du taux de nourriture est contrainte et prévisible.C’est donc en tenant compte de cet écart limité qu’une marque peut estimer le taux de captation et donc la rentabilité de la fidélisation ainsi que le potentiel clientIn this thesis based on works the author goes from two previous studies on the profitability of loyalty and customer potential determination to make a statement : part of the profitability of loyalty and of the potential for a brand is based on the reachable share of turnover done by the competition ; the catch rate.In this new work it is shown that the catch rate is based on the elasticity of the share of category requirement. From a review of the literature and several modeling on scanning panel data the author demonstrates on several markets that elasticity of the share of category requirement is limited and predictable.Then it’s in taking into account this small difference that a brand can estimate the “catchable” rate and therefore the profitability of loyalty and potential of a customer
Books on the topic "Catch-rate"
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Schubert, N. D. A comparison of the catch distribution, harvest rate and survival of wild and cultured Salwein Creek coho salmon. New Westminster, B.C: Dept. of Fisheries and Oceans, Field Services Branch, 1986.
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Schmidt-Hebbel, Klaus, Linda Kaltani, and Ibrahim A. Elbadawi. Post-Conflict Aid, Real Exchange Rate Adjustment, And Catch-Up Growth. The World Bank, 2007. http://dx.doi.org/10.1596/1813-9450-4187.
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Escolano, Julio, Anna Shabunina, and Jaejoon Woo. Puzzle of Persistently Negative Interest Rate-Growth Differentials: Financial Repression or Income Catch-Up? International Monetary Fund, 2011.
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Escolano, Julio, Anna Shabunina, and Jaejoon Woo. Puzzle of Persistently Negative Interest Rate-Growth Differentials: Financial Repression or Income Catch-Up? International Monetary Fund, 2011.
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Escolano, Julio, Anna Shabunina, and Jaejoon Woo. Puzzle of Persistently Negative Interest Rate-Growth Differentials: Financial Repression or Income Catch-Up? International Monetary Fund, 2011.
Find full textBook chapters on the topic "Catch-rate"
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Denham, Ainslie, and Ute Mueller. "Incorporating Survey Data to Improve Space–Time Geostatistical Analysis of King Prawn Catch Rate." In Quantitative Geology and Geostatistics, 13–25. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-2322-3_2.
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"Eels at the Edge: Science, Status, and Conservation Concerns." In Eels at the Edge: Science, Status, and Conservation Concerns, edited by Yves de Lafontaine, Michel Lagacé, Fernand Gingras, Denis Labonté, François Marchand, and Edith Lacroix. American Fisheries Society, 2009. http://dx.doi.org/10.47886/9781888569964.ch15.
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<em>Abstract.—</em>Changes in abundance, seasonal occurrence, and mean size of American eels <em>Anguilla rostrata </em>in the lower St. Lawrence River during the past 50 years were examined. Catch per unit effort indices were calculated from daily catch records of eels captured in an experimental trap fishery and from the personal logbooks of a knowledgeable fisher. These two indices indicated a significant declining trend in eel catch rate by more than 50% since the early 1970s. Interannual fluctuations in catch rate were not related to variability in water level or water temperature. The timing of eel occurrence varied significantly between years and was inversely correlated to water level in August and September. It is hypothesized that eel movement is strongly determined by climatic/hydrological conditions in the previous summer. The average weight of eels has increased by 30% over the past eight years. The decline in catch rate and the increase in mean size of migratory silver eels in recent years are interpreted as the most significant symptoms of low recruitment levels and the precursory signal that the eel fishery in the lower St. Lawrence River may not be sustainable in the near future.
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"Propagated Fish in Resource Management." In Propagated Fish in Resource Management, edited by DANA L. WINKELMAN and CLIFTON SAGER. American Fisheries Society, 2004. http://dx.doi.org/10.47886/9781888569698.ch18.
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<em>Abstract.</em>—Hybrid bluegill are becoming increasingly popular for stocking at youth fishing clinics and urban recreational fisheries. However, no studies have evaluated potential impacts of young anglers (ages 12 and under) on hybrid bluegill. Our objective was to quantify catch rate and short-term angling mortality associated with young anglers on hybrid bluegill. We held two fishing clinics to estimate catch rates of stocked hybrid bluegill and observed anglers for 10-min intervals throughout the clinic. Mean catch rates for hybrid bluegill at two youth fishing clinics were 6.6 and 4.4 fish/ h. We estimated that 65% of stocked hybrid bluegill (<em>n </em>= 400) were captured during a 2-h fishing period. We estimated the influence of stocking density on catch rate to predict appropriate stocking densities. Catch rates in experimental ponds ranged from 1.0 to 35.6 fish/angler-hour at stocking densities ranging from 120 to 2,000 fish/ha, respectively. We also conducted catch and release mortality trials to estimate short-term mortality of fish captured by young anglers. Fish were held in net pens and observed for 36 h following capture. We observed only one death from a total of 80 captured fish during our mortality trials. We developed a simulation model to assess management options. Model results suggest that relatively high catch rates (8–10 fish/h) can be maintained with a modest stocking effort (100 fish/month) for a catch-and-release fishery. Even modest harvest would result in a short-term put-and-take fishery. Empirical and modeling results indicate that hybrid bluegill are suitable candidates for youth fishing clinics and can be managed with catch-and-release regulations.
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Myers, Ransom A. "Testing Ecological Models: The Influence of Catch Rates on Settlement of Fishermen in Newfoundland, 1710-1833." In The Exploited Seas, 13–30. Liverpool University Press, 2001. http://dx.doi.org/10.5949/liverpool/9780973007312.003.0002.
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Ransom A. Myers studies three Newfoundland bays in order to test Scott Gordon’s maxim that renewable resource exploitation becomes unprofitable over time as new exploiters enter the system until profit margins reach zero. He uses a thorough collection of data for each bay, and determines that fishermen in Newfoundland settled if catch rates were greater than forty quintals of dried salt cod per annum, and emigrate if less. He presumes this population movement is reflected in the consistent catch rate in Newfoundland from the 1700s up until the 1990s collapse of the fishery.
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"Biology and Management of Dogfish Sharks." In Biology and Management of Dogfish Sharks, edited by Jackie R. King and Gordon A. McFarlane. American Fisheries Society, 2009. http://dx.doi.org/10.47886/9781934874073.ch8.
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Abstract.—Spiny dogfish <em>Squalus acanthias </em>have been an important component of the Strait of Georgia fisheries from the late 1800s to the late 1940s, when the fishery collapsed owing to overfishing and changes in market demand. The stock population levels have sustained a commercial fishery of approximately 2,000 metric tons since 1978. Recent concerns regarding the status of dogfish stocks worldwide have reprioritized the status assessment of dogfish in British Columbia. Longline research surveys were conducted for dogfish in the Strait of Georgia in 1986, 1989, and 2005. Additional sources of information are catch and effort data collected through logbook records from the commercial longline fishery. Recent improvements in gear configuration resulted in a switch in the mid-1990s from traditional J hooks to circle hooks, which makes direct comparison of catch rates difficult. In November 2004 a calibration experiment using J hooks and circle hooks demonstrated that, overall, spiny dogfish catch per unit effort (CPUE) for circle-hook gear was 1.6–1.7 times higher than that for J-hook gear. After applying this conversion to the commercial longline CPUE data available for 1980–1984 and 2000–2004, no significant trend in catch rate over time was detected. The catch rate observed in the longline research survey actually increased in 2005 compared to 1986 and 1989. In both fisheries and research data, the proportion of smaller spiny dogfish in the size distribution has increased, reducing the overall mean size. The decline in mean size is probably due to an increase in recruitment of juvenile fish. However, caution in management of this stock is warranted given that the current commercial fishery is now landing a large proportion (estimated 80%) of immature fish. Increased fishing pressure on juveniles could have implications for the abundance of mature fish in upcoming decades.
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"Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists." In Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists, edited by John M. Casselman, Jonah L. Withers, and Thomas J. Howson. American Fisheries Society, 2017. http://dx.doi.org/10.47886/9781934874462.ch1.
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<em>Abstract</em>.—Sustainability of trophy Muskellunge <em>Esox masquinongy </em>populations and fisheries was examined from Muskies, Inc. catch data (335,954) from 43 years (1971–2013), along with more than 35 years (late 1970s–2013) of trophy Muskellunge data and cleithra (2,633) submitted to the Cleithrum Project. Catch has increased substantially over the past five decades, but harvest has been greatly reduced because of increased size limits (e.g., in Ontario, set by using growth potential) and voluntary catch and release of legal-sized fish promoted by organized Muskellunge anglers. The Cleithrum Project exemplifies cooperative interaction; although fewer samples have been submitted in recent years, length, weight, and age have increased significantly. Pivotal change occurred in the mid-1990s (means for late 1970s–1994, total length 108.7 cm, total weight 9.7 kg, age 11.6 years; 1995–2013, 121.0 cm, 13.4 kg, 15.1 years). A predictive mortality rate–longevity relationship was used on the Cleithrum Project age data to estimate mortality rate of trophy Muskellunge. Annual mortality rate (<EM>A</EM>) of trophy Muskellunge usually ranged from 16% to 26% and corresponded to maximum ages of 24 to 14 years. Estimated annual mortality of the oldest Muskellunge increased slightly over the past 35 years—13.0% to 14.3%, with a decrease in maximum age from 30 to 27 years. Mortality was high to the mid-1990s but has decreased subsequently, even though angling pressure has increased. Size and mean age of trophy Muskellunge have increased substantially (10.2 to 15.8 years) with associated decreases in annual mortality (<EM>A</EM>, 31.0% to 21.9%), indicating an increase in the mature population and reproductive potential. To ensure sustainable trophy Muskellunge populations, fish younger than 15 years should not be exposed to fishing mortality and older fish should not have a fishing mortality rate that exceeds the rate of natural mortality (<EM>F ≯</EM> <EM>M</EM>). Management for large size (older age) by using excessive size limits, in combination with catch and release, can have unexpected outcomes because older fish are increasingly sensitive to stress (e.g., viral hemorrhagic septicemia [VHS] mortalities). If Muskellunge populations are managed for high reproductive capacity (protecting fish to larger size and older age), they will be more reproductively resilient, producing larger year-classes, better sustaining trophy populations and fisheries.
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"Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists." In Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists, edited by Jason B. Smith, Mary Tate Bremigan, Daniel B. Hayes, and Michael V. Thomas. American Fisheries Society, 2017. http://dx.doi.org/10.47886/9781934874462.ch30.
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<em>Abstract</em>.—The current Lake St. Clair Great Lakes Muskellunge <em>Esox masquinongy </em>fishery is entirely self-sustaining and dominated by a catch-and-release ethic. Catch rates of Lake St. Clair Muskellunge are among the highest documented for this species, and angler catches of trophy Muskellunge are considered relatively commonplace. The proximity of Lake St. Clair to many potential new Muskellunge anglers, interest among some anglers in restoring a long-prohibited winter spear fishery, and warming temperatures associated with climate change pose potential threats to the quality of this fishery. We developed an age-structured equilibrium yield model to project the likely effects of altered size and harvest limits, increased angling effort, establishment of a winter spearing season, or warming temperatures on open-water angling catch rates of three size-classes of Lake St. Clair Muskellunge (all fish ≥ age 1, legal-sized fish > 107 cm, and trophy-sized fish > 127 cm). Our modeling indicated that changes in regulations in the Lake St. Clair Muskellunge fishery were unlikely to result in substantial changes to catch rates of Muskellunge of any size-class. Similarly, the current high rate of voluntary release would largely buffer catch rates of all size-classes of Lake St. Clair Muskellunge from increases in fishing effort. Our simulation of a winter spearing fishery indicated that only high levels of spearing effort and harvest would reduce open-water catch rates to a degree that would likely be objectionable to anglers. In contrast, the predicted catch rates of legal-and trophy-sized fish were highly sensitive to modeled reductions in growth. As such, the major threat to this trophy Muskellunge fishery appears largely outside the traditional toolbox of fisheries managers, hastening the need for development of resilient management and monitoring plans for this valuable fishery.
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Durá-Travé, Teodoro, Isabel San Martín-García, Fidel Gallinas-Victoriano, María Malumbres-Chacón, Paula Moreno-González, and María Urretavizcaya-Martinez. "Characteristics of Catch-Up Growth in Very Low Birth Weight Infants (<1500 g)." In Caesarean Section [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96933.
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Features of catch-up growth are not well established in very low birth weight infants (VLBW). The aim of this study is to analyze the catch-up growth in height and some factors associated in a cohort of VLBW (<1500 g) from birth to age 14 years. Retrospective registration of weight and height at birth and ages 0.5, 1, 2, 3, 4, 6, 8, 10, 12 and 14 years in a cohort of 170 VLBW have been recorded Anthropometric variables were compared with those from a control group. Sixty-nine (40.6%) were small for gestational age (SGA subgroup) and 101 (59.4%) were appropriate for gestational age (AGA subgroup). Thirty-seven (21.8%) were extremely low birth weight (ELBW), and 32 (18.8%) extremely preterm (EPT). At age 2, 4 and 10 years, 49.4%, 78.9% and 87.1% VLBW, respectively, did reach normal height. Between 4 and 10 years of age, only 8.2% of VLBW reached normal height. At 10 years of age, 7% of VLBW (1000–1500 g) and 35% of ELBW (<1500 g) showed short stature (p = 0.001). Almost the entire sample of VLBW with normal height at age 2, 4 and 10 have reached an adequate catch-up growth in weight in the previous evaluations. ELBW, SGA and EPT were found to be independent predictors for inadequate catch-up growth in height at 2, 4, and 10 years of age. The growth pattern of children born preterm has particular features: they have a lower rate and/or slowness in the catch-up growth in height with respect to that described in full-term small-for-gestational-age infants. Catch-up in weight appears to be a decisive factor for catch-up in height, and, on this basis, we recommend a rigorous nutritional follow-up in these individuals. If these measures do not help improve catch-up in height, they may be eligible for the establishment of rhGH therapy.
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"Balancing Fisheries Management and Water Uses for Impounded River Systems." In Balancing Fisheries Management and Water Uses for Impounded River Systems, edited by Dan Garren, Jim Fredericks, Rob Van Kirk, and Damon Keen. American Fisheries Society, 2008. http://dx.doi.org/10.47886/9781934874066.ch27.
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<em>Abstract</em>.—The Idaho Department of Fish and Game has stocked fingerling Yellowstone cutthroat trout <em>Oncorhynchus clarkii bouvieri</em>, hybrid trout (rainbow trout <em>O. mykiss</em> × Yellowstone cutthroat trout), and brook trout <em>Salvelinus fontinalis </em>(hereafter referred to collectively as trout) in Henrys Lake since the early 1900s to supplement natural recruitment and increase angler catch rates. Annual stocking rates have varied from 317 to 1,027 fingerling (approximately 75 mm) trout per hectare from 1971 to present. Stocking densities can influence angler catch rates but are limited by production constraints and costs associated with raising and transporting fish. By refining fingerling trout stocking densities, managers can optimize the fishery and minimize hatchery expenditures. To fully understand the effects of stocking density on angler catch rates in a lake with natural reproduction, we estimated the contribution of hatchery fish to the fishery by analyzing 6 years of marked fingerling stockings and found that natural recruitment added little to the adult population. We then explored the relationships among stocking densities, angler catch rates, and size of fish harvested by anglers to determine the optimal stocking density needed to achieve our management objectives of catch rates 0.7 fish per hour and 10% of harvested Yellowstone cutthroat trout exceeding 500 mm. We found increased catch rates following years when stocking densities were high. However, mean size of Yellowstone cutthroat trout harvested decreased following years of higher stocking densities. We estimate that approximately 737 fingerling trout per hectare are needed annually to achieve angler catch rates of 0.7 fish per hour. At this stocking density, we estimated that approximately 3% of harvested Yellowstone cutthroat trout would exceed 500 mm. This fell below our management objective of 10% of harvested Yellowstone cutthroat trout exceeding 500 mm and suggested that our current catch rate objective and size objective may be incompatible. This information should be combined with angler opinion data to formulate attainable goals for the fishery.
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"The Angler in the Environment: Social, Economic, Biological, and Ethical Dimensions." In The Angler in the Environment: Social, Economic, Biological, and Ethical Dimensions, edited by William Sawynok and John R. Platten. American Fisheries Society, 2011. http://dx.doi.org/10.47886/9781934874240.ch12.
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<i>Abstract</i> .—Central Queensland in Australia already has a highly variable rainfall and streamflow pattern. River flows of the largest local river, the Fitzroy, are seasonal and ephemeral and, between 1976 and 2008, varied in magnitude from around 349,677 to 22,903,390 ML per annum. Predictions of local climate change effects suggest that rainfall and streamflows will become more variable with less frequent but larger flood events and extended, more severe drought periods. SUNTAG is a program that has recorded details of tagged and recaptured fish in Queensland since 1986. CAPREEF is a community-based program that has collected catch-and-effort data from recreational fishers across Central Queensland since 2005. The SUNTAG and CAPREEF programs act as a long-term central repository to collect recreational fish tagging and catch information. The goal of this paper was to examine two models predicting changes associated with rainfall and streamflow, the first examining changes in barramundi <i>Lates calcarifer </i> recruitment in a wetland system and the second predicting changes in recreational catch rate of sand whiting <i>Sillago ciliata </i> and red throat emperor <i>Lethrinus miniatus</i> . Catch rates of young barramundi recruiting to a wetland in the Fitzroy River delta between 1985 and 2008 varied between 0 and 37 fish/d. The median catch rates of fishing clubs also varied widely, being highest in years following wet season flooding.
Conference papers on the topic "Catch-rate"
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Aoyagi, Mitsuhiro, Akihiro Uchibori, Takahi Takata, David L. Y. Louie, and Andrew J. Clark. "Sodium Fire Analysis Using a Sodium Chemistry Package in MELCOR." In 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16751.
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Abstract The Sodium Chemistry (NAC) package in MELCOR has been developed to enhance application to sodium cooled fast reactors. The models in the NAC package have been assessed through benchmark analyses. The F7-1 pool fire experimental analysis is conducted within the framework of the U.S.–Japan collaboration; Civil Nuclear Energy Research and Development Working Group. This study assesses the capability of the pool fire model in MELCOR and provides recommendations for future model improvements because the physics of sodium pool fire are complex. Based on the preliminary results, analytical conditions, such as heat transfer on the floor catch pan are modified. The current MELCOR analysis yields lower values than the experimental data in pool combustion rate and pool, catch pan, and gas temperature during early time. The current treatment of heat transfer for the catch pan is the primary cause of the difference in the results from the experimental data. After sodium discharge stopping, the pool combustion rate and temperature become higher than experimental data. This is caused by absence of a model for pool fire suppression due to the oxide layer buildup on the pool surface. Based on these results, recommendations for future works are needed, such as heat transfer modification in terms of the catch pan and consideration of the effects of the oxide layer for both the MELCOR input model and pool physic.
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Charles C Hillyer, Chad Higgins, and Jason Kelly. "Catch Can Testing of a Variable Rate Irrigation System and Evaluation Using a Time Varying Densogram." In 2013 Kansas City, Missouri, July 21 - July 24, 2013. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2013. http://dx.doi.org/10.13031/aim.20131620517.
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Gando, Ryunosuke, Shunta Maeda, Kei Masunishi, Yasushi Tomizawa, Etsuji Ogawa, Yohei Hatakeyama, Tetsuro Itakura, and Tamio Ikehashi. "A MEMS rate integrating gyroscope based on catch-and-release mechanism for low-noise continuous angle measurement." In 2018 IEEE Micro Electro Mechanical Systems (MEMS). IEEE, 2018. http://dx.doi.org/10.1109/memsys.2018.8346713.
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Krug, Matthias B., Davide Peduto, Wolfram Kurz, and Hans-Jörg Bauer. "Experimental Investigation Into the Efficiency of an Aero Engine Oil Jet Supply System." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-26208.
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This paper presents results of investigations on the interaction between a targeted oil jet and a rotating shaft in an aero engine typical bearing chamber. Measurements were performed at atmospheric temperature and pressure in order to study the influence of the operating conditions, nozzle diameters and impingement angles on the efficiency of such an oil supply system. The flow phenomena of the jet-shaft interaction were visualised. A qualitative analysis of the jet-shaft interaction revealed massive droplet generation due to the jet break-up in the air crossflow and its impact on the shaft. The latter could be reduced with shallower impingement angles. Measurements showed that the oil inflow rate, the shaft speed and the nozzle diameter have a strong influence on the collected oil quantity, which is expressed as catch efficiency, i.e. the ratio of collected and supplied oil. The impingement angle was also identified to have a strong influence on the catch efficiency. The ratio of the momentum fluxes of supplied oil and chamber air flow is proposed as a parameter to correlate the catch efficiency to the operating conditions.
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Nakamura, Kenta, Shota Suzuki, and Shigeru Tabeta. "A Study on the Operation Strategies for Bottom Otter Trawling in Ise Bay." In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-61142.
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In order to simulate the bottom trawl fishery in Ise Bay, a typical semi-enclosed bay in Japan, a fishery simulator has been developed that consists of a fish behavioral model and a fishing operations model. The fish behavioral models are developed for two major target species, conger eel and mantis shrimp, which consider the fish migration as well as the growth and the population change. The fish behavioral models are combined with a fishing operation model, which predicts the behavior of trawling boats based on economic conditions and resource distribution as well as the fish catch amount by each boat. The model is applied to evaluate the effects of fishery management, and it is investigated that how the control of fishing efforts or number of owned fishing boats affects the profit of the target fishery. The mesh size of the trawling net which maximizes the total catch is estimated considering both conger eel and mantis shrimp. At the target ports, reduction of boats number will increase the profit because the effect of fixed cost change exceeds the impact of fish catch decrease. However, the optimum reduction rate is different in each port and interactive effect should be also considered.
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Kikukawa, Koki, and Shigeru Tabeta. "A Preliminary Study on Site Selection for Tidal Current Power Plants in Seto Inland Sea." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-77339.
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Tidal current power generation is one of marine renewable energies whose merit is stable and predictable power generation. In the present study, a potential map of tidal current energy in Seto Inland Sea is developed on GIS from the datasets of hydraulic model experiments. Fisheries value maps are also developed from the database of fish catch for typical species in the target area. The developed maps are integrated through GIS, to investigate suitable locations for tidal current power plants in Seto Inland Sea. From the combined map considering both the economic value of tidal current power generation and the fishery, it is found that the areas with positive total value significantly decrease as damage rate on fishery becomes larger, though the areas with high energy potential of tidal current have larger total economic values even when the damage rate increases. On the other hand, some areas where the fishery value is small will become candidate site when the damage rate on fishery gets larger.
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Murthy, M. S. N., Subhash Kumar, and Sheshadri Sreedhara. "Experimental Analysis of Combustion in Gas Turbine." In ASME 2019 Gas Turbine India Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gtindia2019-2496.
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Abstract This paper presents the methodology and results of an experimental analysis of combustion in a gas turbine combustor. The experimental setup is designed to imitate the conditions of a working gas turbine engine (GT), using an actual gas turbine combustor. Air is supplied by a heavy-duty air compressor at a maximum pressure of 7 bar to the combustor through an air pipe catering to the developing length. The air flow rate is measured using an ASME standard Venturimeter along with a manometer. The air flow rate and pressure are controlled by a combination of air outlet valve placed before developing length and by a throttle orifice in the exhaust duct at combustor outlet. Diesel fuel used in the experiments is provided at required atomizing pressure by a gear pump. Mass flow rate and pressure of fuel is controlled by combination of valves and varying the speed of gear pump using a variable speed electric motor. Combustion is initiated in a conventional pilot ignition unit using a spark plug and fuel burner. Fuel flow rate is measured accurately using a unique catch and time measuring system at the inlet of the gear pump.
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Flynn, Eric, and Michael Todd. "Optimal Sensor Placement for Active Sensing." In ASME 2008 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2008. http://dx.doi.org/10.1115/smasis2008-439.
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We present a novel approach for optimal actuator and sensor placement for active sensing-based structural health monitoring (SHM). Of particular interest is the optimization of actuator-sensor arrays making use of Lamb wave propagation for detecting damage in thin plate-like structures. Using a detection theory framework, we establish the optimum configuration as the minimization of the expected percentage of the structure to show type I or type II error during the damage detection process. The detector incorporates a statistical model of the active sensing process which implements both pulse-echo and pitch-catch actuation schemes and takes into account line of site and non-uniform damage probabilities. The optimization space was searched using a genetic algorithm with a time varying mutation rate. We provide four example actuator/sensor placement scenarios and the optimal solutions as generated by the algorithm.
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Takeyama, Daiki, Chikako Iwaki, Yoichi Onitsuka, and Mika Tahara. "Study on Thermal-Hydraulics Characteristics of the Flat and High-Thermal-Conductivity Core-Catcher." In 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-82046.
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For mitigation of severe accident with core melting, core-catcher has been developed to catch and cool molten core. The core-catcher developed by Toshiba for Advanced Boiling Water Reactor was designed to be installed under Reactor Pressure Vessel (RPV) and catch molten core in basin with thermal-resistant material. It also has structure including risers and downcomers to generate natural circulation flow of cooling water. On the other hand, there is not enough space to install it in the existing plants due to the height of the inclined cooling channels. Then, we have been developing flat core-catcher with flat cooling channels for the existing plants to reduce total height of the structure. Finned channels will be adopted to increase heat transfer rate by increasing heat transfer area. However, the thermal-hydraulics characteristics of such core-catcher has not been clarified due to the specific configuration, that is, the horizontal rectangular finned channel with the heated surface from upper side. This present study investigated the natural circulation characteristics and heat transfer behavior in the horizontal rectangular finned channel by experiment. Pressure drop, natural circulation flow and temperature were measured by changing heat fluxes. The flow was visualized to obtain flow pattern in the finned channel by a high-speed camera. The maximum value of test range of heat flux was 250 kW/m2, which is the value when the total amount of the molten core would be dropped to the core-catcher. The partial simulated test section of finned channel with 3.5 m length was heated from upper side by heaters to simulate the heat flux from the molten core. This length is the same as the inner diameter of RPV pedestal of the existing plants. The natural circulation mass flux increased as the heat flux increased and then two-phase flow pressure loss also increased. Consequently, circulation flow turned to decrease. As a result of the test, when the heat flux was 50 kW/m2, the circulation mass flux got to the maximum value, 230 kg/m2s. Under all the conditions except for the maximum heat flux of 250 kW/m2, the fin surface temperature was around the saturated temperature. At maximum heat flux 250 kW/m2, the temperature got 540 K. However, the structural soundness was maintained because it is lower than melting temperature of the fin. It can be concluded that the flat and high-thermal-conductivity core-catcher has enough cooling performance to catch and stabilize the molten core.
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Qian, Zhengyu, and Di Yun. "Investigation of Swelling Behaviors of U-10Zr Metallic Fuel in the Low Temperature Regime via a Combined Thermo-Mechanical and Rate Theory Analysis." In 2022 29th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/icone29-92285.
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Abstract Uranium zirconium (U-Zr) metallic nuclear fuel has long been considered as a promising candidate for fast reactor fuel in the past few decades duo to its excellent performance. One of the key performance problems of U-10Zr metallic fuel is its strong swelling which would lead to significant fuel cladding mechanical interaction (FCMI) at high burn-ups. Therefore, the mechanism of fuel swelling has long been a concern of great interest in a wide range of this fields. Recently published research conducted by the Institute of Nuclear Physics and Chemistry in China got the experimental results of U-10Zr fuel swelling in a low temperature regime (400–600K) which showed perceivable swelling of the in-pile irradiated fuel. The previous exploration on the swelling mechanism of uranium zirconium metal fuel at low temperature can’t be carried out due to the lack of data and this research filled the gap for the swelling data of uranium zirconium metallic fuel at low temperature. In our work, combined with the input parameters given by finite element analysis, we utilized a rate theory code based on the cavitational void swelling model to catch the fuel swelling behaviors of the U-10Zr fuel in the low temperature regime building upon these data. And a new set of key parameters for the rate theory model were also determined.
Reports on the topic "Catch-rate"
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Bryant, C. A., S. A. Wilks, and C. W. Keevil. Survival of SARS-CoV-2 on the surfaces of food and food packaging materials. Food Standards Agency, November 2022. http://dx.doi.org/10.46756/sci.fsa.kww583.
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COVID-19, caused by the SARS-CoV-2 virus, was first reported in China in December 2019. The virus has spread rapidly around the world and is currently responsible for 500 million reported cases and over 6.4 million deaths. A risk assessment published by the Foods Standards Agency (FSA) in 2020 (Opens in a new window) concluded that it was very unlikely that you could catch coronavirus via food. This assessment included the worst-case assumption that, if food became contaminated during production, no significant inactivation of virus would occur before consumption. However, the rate of inactivation of virus on products sold at various temperatures was identified as a key uncertainty, because if inactivation does occur more rapidly in some situations, then a lower risk may be more appropriate. This project was commissioned to measure the rate of inactivation of virus on the surface of various types of food and food packaging, reducing that uncertainty. The results will be used to consider whether the assumption currently made in the risk assessment remains appropriate for food kept at a range of temperatures, or whether a lower risk is more appropriate for some. We conducted a laboratory-based study, artificially contaminating infectious SARS-CoV-2 virus onto the surfaces of foods and food packaging. We measured how the amount of infectious virus present on those surfaces declined over time, at a range of temperatures and relative humidity levels, reflecting typical storage conditions. We tested broccoli, peppers, apple, raspberry, cheddar cheese, sliced ham, olives, brine from the olives, white and brown bread crusts, croissants and pain au chocolat. The foods tested were selected as they are commonly sold loose on supermarket shelves or uncovered at deli counters or market stalls, they may be difficult to wash, and they are often consumed without any further processing i.e. cooking. The food packaging materials tested were polyethylene terephthalate (PET1) trays and bottles; aluminium cans and composite drinks cartons. These were selected as they are the most commonly used food packaging materials or consumption of the product may involve direct mouth contact with the packaging. Results showed that virus survival varied depending on the foods and food packaging examined. In several cases, infectious virus was detected for several hours and in some cases for several days, under some conditions tested. For a highly infectious agent such as SARS-CoV-2, which is thought to be transmissible by touching contaminated surfaces and then the face, this confirmation is significant. For most foods tested there was a significant drop in levels of virus contamination over the first 24 hours. However, for cheddar cheese and sliced ham, stored in refrigerated conditions and a range of relative humidity, the virus levels remained high up to a week later, when the testing period was stopped. Both cheddar cheese and sliced ham have high moisture, protein and saturated fat content, possibly offering protection to the virus. When apples and olives were tested, the virus was inactivated to the limit of detection very quickly, within an hour, when the first time point was measured. We suggest that chemicals, such as flavonoids, present in the skin of apples and olives inactivate the virus. The rate of viral decrease was rapid, within a few hours, for croissants and pain au chocolat. These pastries are both coated with a liquid egg wash, which may have an inhibitory effect on the virus. Food packaging materials tested had variable virus survival. For all food packaging, there was a significant drop in levels of virus contamination over the first 24 hours, in all relative humidity conditions and at both 6°C and 21°C; these included PET1 bottles and trays, aluminium cans and composite drinks cartons.