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Sampling Volume (sampling + volume)
Selected AbstractsOmnidirectional multibeam sonar monitoring: applications in fisheries scienceFISH AND FISHERIES, Issue 3 2006Patrice Brehmer Abstract Data exploitation, acquired by medium-frequency omnidirectional multibeam sonar, enables original studies in fisheries research but is seldom used despite the fact that such equipment is found on most fishing vessels and a number of research vessels. This is the only system for real-time monitoring of fish schools within a horizontal omnidirectional plane about a vessel or a buoy. Between 1996 and 2001, we used two standard omnidirectional sonars and developed new methodologies for exploiting their specific acoustic data according to two main sampling schemes: ,prospecting', including fishing and searching operations, and ,drifting', as with an instrumental buoy system or aboard a stationary vessel. We present a complete method for continuous data acquisition from aboard a research vessel or commercial boat, with automated data extraction by picture analysis and a data processing method. Two cases of data analysis are considered: the first on a school-by-school basis, the ,single school' mode; the second taking into account all fish schools detected within the sonar sampling volume, the ,cluster' mode. Elementary sonar information is divided into five categories that comprise 24 survey and sonar parameters and 55 school, cluster and fisher behaviour descriptors. We review the applications of these categories and discuss perspectives for their use in fisheries science. If the sonar system enables the evaluation of the effects of vessel avoidance on fish school biomass assessment, no accurate abundance estimate can be provided by a simple sonar echo-integration process. Omnidirectional sonar data can be used to analyse collectively the fish schools' swimming speed, kinematics in terms of diffusion and migration, aggregative dynamics as school splitting and merging indexes, spatial characteristics of clusters such as school density, 2D structure and fisher behaviour. The prospect of integrating such data into a fish school database, including multifrequency echo-sounder and lateral multibeam (3D) sonar data combined with a species recognition method, will enable a complete view of fish school behaviour and consequently the adoption of accurate fisheries management methods. [source] Application of functional group modified substrate in room-temperature phosphorescence, I,, -cyclodextrin modified paper substrate for enrichment and determination of fluorene and acenaphtheneLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 4-5 2005Ruohua Zhu Abstract A novel method for the determination of fluorene and acenaphthene on solid phase extraction,room-temperature phosphorescence (SPE,RTP) was studied. , -cyclodextrin (, -CD) was chemically bonded onto chromatography paper by reaction with epichorohydrin in an ultrasonic bath. The RTP signal of fluorene and acenaphthene included on the , -CD-modified paper was increased more than 10 times compared with non-modified filter paper, indicating the formation of the inclusion complex. The conditions for the of RTP of compounds were studied in detail. The linear ranges of fluorene and acenaphthene concentrations to the RTP intensity were over two orders of magnitude (8.0 × 10,7,4.0 × 10,5 mol/L for fluorene) with a correlation coefficient of 0.999. The concentration limits of detection for fluorene and acenaphthene were 1.11 × 10,8 mol/L and 3.8 × 10,7 mo/L, respectively. When the sampling volume was 10 µL, the absolute LODs for fluorene and acenaphthene were 18.4 pg/spot and 0.58 ng/spot, respectively. The modified filter paper was used for solid phase extraction (SPE) and the retention behaviour of fluorene and acenaphthene was examined. The enrichment efficiency of the analytes was higher than 100-fold. The SPE,RTP coupling technique was applied directly to the determination of fluorene and acenaphthnene in environmental water samples. Copyright © 2005 John Wiley & Sons, Ltd. [source] Sensitive determination of bromine and iodine in aqueous and biological samples by electrothermal vaporization inductively coupled plasma mass spectrometry using tetramethylammonium hydroxide as a chemical modifierRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2008Hiroko Kataoka A procedure for the simultaneous determination of bromine and iodine by inductively coupled plasma (ICP) mass spectrometry was investigated. In order to prevent the decrease in the ionization efficiencies of bromine and iodine atoms caused by the introduction of water mist, electrothermal vaporization was used for sample introduction into the ICP mass spectrometer. To prevent loss of analytes during the drying process, a small amount of tetramethylammonium hydroxide solution was placed as a chemical modifier into the tungsten boat furnace. After evaporation of the solvent, the analytes instantly vaporized and were then introduced into the ICP ion source to detect the 79Br+, 81Br+, and 127I+ ions. By using this system, detection limits of 0.77,pg and 0.086,pg were achieved for bromine and iodine, respectively. These values correspond to 8.1,pg,mL,1 and 0.91,pg,mL,1 of the aqueous bromide and iodide ion concentrations, respectively, for a sampling volume of 95,µL. The relative standard deviations for eight replicate measurements were 2.2% and 2.8% for 20,pg of bromine and 2,pg of iodine, respectively. Approximately 25 batches were vaporizable per hour. The method was successfully applied to the analysis of various certified reference materials and practical situations as biological and aqueous samples. There is further potential for the simultaneous determination of fluorine and chlorine. Copyright © 2008 John Wiley & Sons, Ltd. [source] A deconvolution method for the reconstruction of underlying profiles measured using large sampling volumesJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3 2006Y.-S. Xiong A deconvolution method for diffraction measurements based on a statistical learning technique is presented. The radial-basis function network is used to model the underlying function. A full probabilistic description of the measurement is introduced, incorporating a Bayesian algorithm based on an evidence framework. This method allows predictions of both the convolution and the underlying function from noisy measurements. In addition, the method can provide an estimation of the prediction uncertainty, i.e. error-bars. In order to assess the capability of the method, the model was tested first on synthetic data of controllable quality and sparsity; it is shown that the method works very well, even for inaccurately measured (noisy) data. Subsequently, the deconvolution method was applied to real data sets typical of neutron and synchrotron residual stress (strain) data, recovering features not immediately evident in the large-gauge-volume measurements themselves. Finally, the extent to which short-period components are lost as a function of the measurement gauge dimensions is discussed. The results seem to indicate that for a triangular sensor-sensitivity function, measurements are best made with a gauge of a width approximately equal to the wavelength of the expected strain variation, but with a significant level of overlap (,80%) between successive points; this is contrary to current practice for neutron strain measurements. [source] | ||||||||||