968 resultados para Fourier modal method


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An in-depth knowledge about the characteristics of lightning generated currents will facilitate evaluation of the interception efficacy of lightning protection systems. In addition, it would aid in extraction of valuable statistics (from measured current data) on local lightning parameters. Incidentally, present day knowledge on characteristics of lightning induced current in typical lightning protection systems is rather limited. This is particularly true with closely interconnected protection systems, like the one employed in Indian Satellite Launch Pad-II. This system is taken as a specific example in the present study. Various aspects suggest that theoretical modelling would be the best possible approach for the intended work. From the survey of pertinent literature, it is concluded that electromagnetic modelling of lightning return-stroke with current source at the channel base is best suited for this study. Numerical electromagnetic code was used for the required electromagnetic field solution and Fourier transform techniques were employed for computing time-domain results. A validation for the numerical modelling is provided by laborator experiments on a reduced scale model of the system. Apart from ascertaining the influence of various parameters, salient characteristics of tower base currents for different kinds of events are deduced. This knowledge can be used in identifying the type of event, as well as its approximate location. A method for estimation of injected stroke current has also been proposed.

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Increased mass migration, as a result of economic hardship, natural disasters and wars, forces many people to arrive on the shores of cultures very different from those they left. How do they manage the legacy of the past and the challenges of their new everyday life? This is a study of immigrant women living in transnational families that act and communicate across national borders on a near-daily basis. The research was carried out amongst immigrant women who were currently living in Finland. The research asks how transnational everyday life is constructed. As everyday life, due to its mundane nature, is difficult to operationalise for research purposes, mixed data collection methods were needed to capture the passing moments that easily become invisible. Thus, the data were obtained from photographic diaries (459 photographs) taken by the research participants themselves. Additionally, stimulated recall discussions, structured questionnaires and participant observation notes were used to complement the photographic data. A tool for analysing the activities devealed in the data was created on the assumption that a family is an active unit that accommodates the current situation in which it is embedded. Everyday life activities were analysed emphasizing social, modal and spatial dimensions. Important daily moments were placed on a continuum: for me , for immediate others and with immediate others . They portrayed everyday routines and exceptions to it. The data matrix was developed as part of this study. The spatial dimensions formed seven units of activity settings: space for friendship, food, resting, childhood, caring, space to learn and an orderly space. Attention was also paid to the accommodative nature of activities; how women maintain traditions and adapt to Finnish life or re-create new activity patterns. Women s narrations revealed the importance of everyday life. The transnational chain of women across generations and countries, comprised of the daughters, mothers and grandmothers was important. The women showed the need for information technology in their transnational lives. They had an active relationship to religion; the denial or importance of it was obvious. Also arranging one s life in Finnish society was central to their narrations. The analysis exposed everyday activities, showed the importance of social networks and the uniqueness of each woman and family. It revealed everyday life in a structured way. The method of analysis that evolved in this study together with the research findings are of potential use to professionals, allowing the targeting of interventions to improve the everyday lives of immigrants.

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A rapid and sensitive method is described to quantitatively compare tRNA pools for individual aminoacids in a single experiment. The procedure comprises of: (i) charging of total tRNA with a mixture of radiolabeled aminoacids, (ii) deacylation of the esterified tRNA with a volatile base and the recovery of the labeled aminoacid, (iii) derivatisation of the aminoacid with phenylisothiocyanate after mixing with excess of nonradioactive aminoacids, (iv) baseline separation of the phenylthiocarbamyl aminoacids by reverse phase high performance liquid chromatography monitored by A254nm and (v) quantitation of the radioactivity in individual aminoacid peaks. The radioactivity in the aminoacid peak corresponds to the quantity of the aminoacylated tRNA. The method has been successfully applied to quantitate the individual tRNA pools in the developing silk glands of Bombyx mori, a functionally adapted tissue which undergoes considerable variations in tRNA content. PSG, posterior silk gland; PITC, phenylisothiocyanate; DMAA, N,N-dimethyl-N-allylamine; APH, algal protein hydrolysate; ptc-, phenylthiocarbamyl; HPLC, high performance liquid chromatography.

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To evaluate the underreporting rate of death -cause data in Shandong province during 2012 to 2013 by capture -mark -recapture method and to provide the base for health strategy. Methods All counties were divided into 5 stratifications according the death rates of 2012, and 14 counties were selected, then 3 towns or streets were selected in each country, 10 villages or neighborhood committees were selected in each town (street). The death data collected from security bureau and civil affairs bureau were compared with the reporting death data from the National Cause of Death Surveillance, and the underreporting rate was calculated. Results In present study, 6 929 death cases were collected, it was found that 1 556 cases were underreported. The death cases estimated by CMR method were 6 227 cases (95%CI: 7 593-7 651), and the average underreporting rate was 23.15%. There were significantly differences between different stratifications (P<0.01). The underreporting rate in 0-4 years old group was 56.93%, the male underreporting rate was 22.31% and the female underreporting rate was 24.09%. There was no significant difference between male and female groups (P>0.05). Conclusion There is an obvious underreport in the cause of death surveillance of Shandong province, and the underreporting rates are different among the 5 stratifications. The underreporting rate is higher in 0-4 years old group, and the investigation of the death cause surveillance for young residents is not perfect in some countries. The investigation quality of the death cause surveillance should be improved, increasing the integrity of the report data and adjusting the mortalities in different stratifications for obtaining a accurate mortality in Shandong province.

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For any construction activity in expansive soils, determination of swelling pressure/heave is an essential step. Though many attempts have been made to develop laboratory procedures by using the laboratory one-dimensional oedometer to determine swelling pressure of expansive soils, they are reported to yield varying results. The main reason for these variations could be heterogeneous moisture distribution of the sample over its thickness. To overcome this variation the experimental procedure should be such that the soil gets fully saturated. Attempts were made to introduce vertical sand drains in addition to the top and bottom drains. In this study five and nine vertical sand drains were introduced to experimentally find out the variations in the swell and swelling pressure. The variations in the moisture content at middle, top, and bottom of the sample in the oedometer test are also reported. It is found that swell-load method is better as compared to zero-swell method. Further, five number of vertical sand drains are found to be sufficient to obtain uniform moisture content distribution.

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Industry acceptance of alternative sulphite treatments for preventing blackspot in prawns is limited. This study demonstrated that dipping prawns (Penaeus monodon and Fenneropenaeus merguiensis) in a less concentrated solution for longer times provides better control of blackspot formation than the recommended 2 minute dip in 50 mg/L 4-hexylresorcinol. Protection improved as modified dipping times and solution concentrations increased. Blackspot protection provided by most of the modified dip methods was more effective than a 1 minute dip in 1% sodium metabisulphite. The recommended 2 minute dip method should be limited to 125 kg when used on consecutive 25-kg batches of prawns. Yields increased by less than 10% even after 72-hour exposure in the modified dip. The new dipping method meets most international residue standards when applying the modified treatments evaluated.

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The hydrodynamical problem of flow in proximal renal tubule is investigated by considering axisymmetric flow of a viscous, incompressible fluid through a long narrow tube of varying cross-section with reabsorption at the wall. Two cases for reabsorption have been studied (i) when the bulk flow,Q, decays exponentially with the axial distancex, and (ii) whenQ is an arbitrary function ofx such thatQ-Q 0 can be expressed as a Fourier integral (whereQ 0 is the flux atx=0). The analytic expressions for flow variables have been obtained by applying perturbation method in terms of wall parameter ε. The effects of ε on pressure drop across the tube, radial velocity and wall shear have been studied in the case of exponentially decaying bulk flow and it has been found that the results are in agreement with the existing ones for the renal tubules.

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This thesis developed an advanced computational model to investigate the motion and deformation properties of red blood cells in capillaries. The novel model is based on the meshfree particle methods and is capable of modelling the large deformation of red blood cells moving through blood vessels. The developed model was employed to simulate the deformation behaviour of healthy and malaria infected red blood cells as well as the motion of red blood cells in stenosed capillaries.

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In this paper, a refined classic noise prediction method based on the VISSIM and FHWA noise prediction model is formulated to analyze the sound level contributed by traffic on the Nanjing Lukou airport connecting freeway before and after widening. The aim of this research is to (i) assess the traffic noise impact on the Nanjing University of Aeronautics and Astronautics (NUAA) campus before and after freeway widening, (ii) compare the prediction results with field data to test the accuracy of this method, (iii) analyze the relationship between traffic characteristics and sound level. The results indicate that the mean difference between model predictions and field measurements is acceptable. The traffic composition impact study indicates that buses (including mid-sized trucks) and heavy goods vehicles contribute a significant proportion of total noise power despite their low traffic volume. In addition, speed analysis offers an explanation for the minor differences in noise level across time periods. Future work will aim at reducing model error, by focusing on noise barrier analysis using the FEM/BEM method and modifying the vehicle noise emission equation by conducting field experimentation.

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Fine powders of TiO2 (rutile) with high degree of crystallinity are formed from aqueous titanium oxychloride solution under hydrothermal conditions at 160–230°C and 15–100 kg/cm2 for 1–2 hours. The anatase phase is produced from the same medium when sulfate ion impurity is present, with Image . Both these fine powders are converted to BaTiO3, SrTiO3 or CaTiO3 when suspended in Ba(OH)2 or Sr(OH)2 solution or in an aqueous slurry of carbonate-free CaO with Image , at 180–280°C and 12–65 kg/cm2 for 4–8 hours. The resulting fine powders contain monocrystallites of the perovskite phase with 0.1–1.5 μm particle size.

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The often discussed role of surface hydroxylation of TiO2 particles as an essential characterestics for their photocatalytic activity can be verified by preparing TiO2 powders by hydrothermal method since hydroxylated surface layers will be better retained on these particles formed in superheated water. Thus, fine powders of TiO2 (rutile) with high degree of crystallinity are formed from titanium oxychloride in the mixed solvent of water and 2-propanol at 160–230°C and 20–120 atm. The anatase phase is produced from the same medium when sulfate ion impurity is present, with Image . TiO2 powders are washed free of anions and 2-propanol by ultrafiltration and are Pt mounted by a photochemical method. Aqueous suspensions of both forms of TiO2 neither as such nor after Pt-loading, do not produce H2 on band gap illumination whereas, H2 is generated in presence of hole scavengers such as EDTA, TEOA, sulfite or hypophosphite. The effects of hole scavenger concentration, Pt : TiO2 ratio, particulate suspension density and the nature of hole scavengers on H2 production are presented. Platinised rutile powders are equally active as anatase in sacrificial systems.

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This paper focuses on the methodological effectiveness of intergenerational collaborative drawing (ICD). A group of eight researchers trialled this particular approach to drawing, most of them for the first time. Each researcher drew with young children, peers and tertiary students, with drawings created over a period of six months. The eight researchers came together in a 'community of scholars' approach to this project because of two shared interests: (i) issues of social justice, access and equity; and (ii) arts-based education research methods. The researchers were curious how ICD might methodologically support their respective research processes. As knowledge and theory about young children becomes more complex, researchers need responsive methodological tools to ask new questions and conduct rigorous, ethical research. This partial account describes how drawing together might perform methodologically. The data reported here draws from the detailed field notes, drawings and reflections of the researchers. Conclusions arise from the analysis of these reflections, with the authors suggesting ways in which ICD might benefit research with young children.

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Abstaract is not available.

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The method of initial functions has been applied for deriving higher order theories for cross-ply laminated composite thick rectangular plates. The equations of three-dimensional elasticity have been used. No a priori assumptions regarding the distribution of stresses or displacements are needed. Numerical solutions of the governing equations have been presented for simply supported edges and the results are compared with available ones.

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Simultaneous recordings of spike trains from multiple single neurons are becoming commonplace. Understanding the interaction patterns among these spike trains remains a key research area. A question of interest is the evaluation of information flow between neurons through the analysis of whether one spike train exerts causal influence on another. For continuous-valued time series data, Granger causality has proven an effective method for this purpose. However, the basis for Granger causality estimation is autoregressive data modeling, which is not directly applicable to spike trains. Various filtering options distort the properties of spike trains as point processes. Here we propose a new nonparametric approach to estimate Granger causality directly from the Fourier transforms of spike train data. We validate the method on synthetic spike trains generated by model networks of neurons with known connectivity patterns and then apply it to neurons limultaneously recorded from the thalamus and the primary somatosensory cortex of a squirrel monkey undergoing tactile stimulation.