Method for Lumped Parameter simulation of Digital Displacement pumps/motors based on CFD

DEFF Research Database (Denmark)

Rømer, Daniel; Johansen, Per; Pedersen, Henrik C.

2013-01-01

Digital displacement fluid power pumps/motors offers improved efficiency and performance compared to traditional variable displacement pump/motors. These improvements are made possible by using efficient electronically controlled seat valves and careful design of the flow geometry. To optimize...... the design and control of digital displacement machines, there is a need for simulation models, preferably models with low computational cost. Therefore, a low computational cost generic lumped parameter model of digital displacement machine is presented, including a method for determining the needed model...... parameters based on steady CFD results, in order to take detailed geometry information into account. The response of the lumped parameter model is compared to a computational expensive transient CFD model for an example geometry....

Improved lumped parameter for annular fuel element thermohydraulic analysis

International Nuclear Information System (INIS)

Duarte, Juliana Pacheco; Su, Jian; Alvim, Antonio Carlos Marques

2011-01-01

Annular fuel elements have been intensively studied for the purpose of increasing power density in light water reactors (LWR). This paper presents an improved lumped parameter model for the dynamics of a LWR core with annular fuel elements, composed of three sub-models: the fuel dynamics model, the neutronics model, and the coolant energy balance model. The transient heat conduction in radial direction is analyzed through an improved lumped parameter formulation. The Hermite approximation for integration is used to obtain the average temperature of the fuel and cladding and also to obtain the average heat flux. The volumetric heat generation in fuel rods was obtained with the point kinetics equations with six delayed neutron groups. The equations for average temperature of fuel and cladding are solved along with the point kinetic equations, assuming linear reactivity and coolant temperature in cases of reactivity insertion. The analytical development of the model and the numeric solution of the ordinary differential equation system were obtained by using Mathematica 7.0. The dynamic behaviors for average temperatures of fuel, cladding and coolant in transient events as well as the reactor power were analyzed. (author)

Numerical analysis of the resonance mechanism of the lumped parameter system model for acoustic mine detection

International Nuclear Information System (INIS)

Wang Chi; Zhou Yu-Qiu; Shen Gao-Wei; Wu Wen-Wen; Ding Wei

2013-01-01

The method of numerical analysis is employed to study the resonance mechanism of the lumped parameter system model for acoustic mine detection. Based on the basic principle of the acoustic resonance technique for mine detection and the characteristics of low-frequency acoustics, the ''soil-mine'' system could be equivalent to a damping ''mass-spring'' resonance model with a lumped parameter analysis method. The dynamic simulation software, Adams, is adopted to analyze the lumped parameter system model numerically. The simulated resonance frequency and anti-resonance frequency are 151 Hz and 512 Hz respectively, basically in agreement with the published resonance frequency of 155 Hz and anti-resonance frequency of 513 Hz, which were measured in the experiment. Therefore, the technique of numerical simulation is validated to have the potential for analyzing the acoustic mine detection model quantitatively. The influences of the soil and mine parameters on the resonance characteristics of the soil—mine system could be investigated by changing the parameter setup in a flexible manner. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Dynamic analysis of the 7-GeV APS experiment hall foundation based on equivalent lumped parameter modeling

International Nuclear Information System (INIS)

Wambsganss, M.W.

1989-01-01

In this technical note, mass-spring-dashpot, also referred to as equivalent lumped parameter, models are employed to model the soil-foundation interaction of two typical floor segments from the 7-GeV APS experiment hall. Equivalent lumped parameter models have the advantage of being easy to apply and of readily allowing for parameter studies. Analysis requires knowledge of certain properties of the soil including density, shear wave velocity, and Poisson's ratio, as well as knowledge of the degree of homogeneity of the underlying soil stratum. These data for the APS site were determined by a geotechnical investigation. A soil profile and pertinent data, obtained from crosshole seismic testing, are given. Natural frequencies and damping are calculated for the vertical, sliding, rocking, and coupled rocking/sliding modes of vibration. Subsequently, various corrections to account for modeling ''deficiencies'' are considered and their influences evaluated. The equivalent lumped parameter models were developed for machine foundations which, compared with the APS foundation, are smaller in plan dimension. Therefore, the applicability of these models in the analysis of the dynamic characteristics of the APS foundation must be established. The modeling is evaluated by applying the equivalent lumped parameter models in the analysis of large foundations for which test data exists. A comparison of theoretical and test results establishes the basis for an assessment of the applicability and accuracy of the modeling

Characterization of the pharmacokinetics of gasoline using PBPK modeling with a complex mixtures chemical lumping approach.

Science.gov (United States)

Dennison, James E; Andersen, Melvin E; Yang, Raymond S H

2003-09-01

Gasoline consists of a few toxicologically significant components and a large number of other hydrocarbons in a complex mixture. By using an integrated, physiologically based pharmacokinetic (PBPK) modeling and lumping approach, we have developed a method for characterizing the pharmacokinetics (PKs) of gasoline in rats. The PBPK model tracks selected target components (benzene, toluene, ethylbenzene, o-xylene [BTEX], and n-hexane) and a lumped chemical group representing all nontarget components, with competitive metabolic inhibition between all target compounds and the lumped chemical. PK data was acquired by performing gas uptake PK studies with male F344 rats in a closed chamber. Chamber air samples were analyzed every 10-20 min by gas chromatography/flame ionization detection and all nontarget chemicals were co-integrated. A four-compartment PBPK model with metabolic interactions was constructed using the BTEX, n-hexane, and lumped chemical data. Target chemical kinetic parameters were refined by studies with either the single chemical alone or with all five chemicals together. o-Xylene, at high concentrations, decreased alveolar ventilation, consistent with respiratory irritation. A six-chemical interaction model with the lumped chemical group was used to estimate lumped chemical partitioning and metabolic parameters for a winter blend of gasoline with methyl t-butyl ether and a summer blend without any oxygenate. Computer simulation results from this model matched well with experimental data from single chemical, five-chemical mixture, and the two blends of gasoline. The PBPK model analysis indicated that metabolism of individual components was inhibited up to 27% during the 6-h gas uptake experiments of gasoline exposures.

Reservoir theory, groundwater transit time distributions, and lumped parameter models

International Nuclear Information System (INIS)

Etcheverry, D.; Perrochet, P.

1999-01-01

The relation between groundwater residence times and transit times is given by the reservoir theory. It allows to calculate theoretical transit time distributions in a deterministic way, analytically, or on numerical models. Two analytical solutions validates the piston flow and the exponential model for simple conceptual flow systems. A numerical solution of a hypothetical regional groundwater flow shows that lumped parameter models could be applied in some cases to large-scale, heterogeneous aquifers. (author)

Patient-specific parameter estimation in single-ventricle lumped circulation models under uncertainty

Science.gov (United States)

Schiavazzi, Daniele E.; Baretta, Alessia; Pennati, Giancarlo; Hsia, Tain-Yen; Marsden, Alison L.

2017-01-01

Summary Computational models of cardiovascular physiology can inform clinical decision-making, providing a physically consistent framework to assess vascular pressures and flow distributions, and aiding in treatment planning. In particular, lumped parameter network (LPN) models that make an analogy to electrical circuits offer a fast and surprisingly realistic method to reproduce the circulatory physiology. The complexity of LPN models can vary significantly to account, for example, for cardiac and valve function, respiration, autoregulation, and time-dependent hemodynamics. More complex models provide insight into detailed physiological mechanisms, but their utility is maximized if one can quickly identify patient specific parameters. The clinical utility of LPN models with many parameters will be greatly enhanced by automated parameter identification, particularly if parameter tuning can match non-invasively obtained clinical data. We present a framework for automated tuning of 0D lumped model parameters to match clinical data. We demonstrate the utility of this framework through application to single ventricle pediatric patients with Norwood physiology. Through a combination of local identifiability, Bayesian estimation and maximum a posteriori simplex optimization, we show the ability to automatically determine physiologically consistent point estimates of the parameters and to quantify uncertainty induced by errors and assumptions in the collected clinical data. We show that multi-level estimation, that is, updating the parameter prior information through sub-model analysis, can lead to a significant reduction in the parameter marginal posterior variance. We first consider virtual patient conditions, with clinical targets generated through model solutions, and second application to a cohort of four single-ventricle patients with Norwood physiology. PMID:27155892

Lumped-parameter fuel rod model for rapid thermal transients

International Nuclear Information System (INIS)

Perkins, K.R.; Ramshaw, J.D.

1975-07-01

The thermal behavior of fuel rods during simulated accident conditions is extremely sensitive to the heat transfer coefficient which is, in turn, very sensitive to the cladding surface temperature and the fluid conditions. The development of a semianalytical, lumped-parameter fuel rod model which is intended to provide accurate calculations, in a minimum amount of computer time, of the thermal response of fuel rods during a simulated loss-of-coolant accident is described. The results show good agreement with calculations from a comprehensive fuel-rod code (FRAP-T) currently in use at Aerojet Nuclear Company

Steady And Unsteady Lumped-Parameter Models For Determination of Groundwater Residence Time Distribution

International Nuclear Information System (INIS)

Oezyurt, N.N.

2002-01-01

Groundwater's residence time distribution is an important information to identify the transport mechanism in aquifer systems. In the absence or scarcity of geometric, hydraulic and geohydrologic data needed to describe a flow system, lumped parameter models, that handle the flow system as a whole, exist as an alternative to determine the residence time distribution. Lumped parametre models comprise of idealized models of piston and well-mixed flow and their combinations. Aquifer properties such as, dead volume and by-pass flow can also be included in these models. With the aid of these models, conceptual aquifer models can be tested and residence time distribution of groundwater can be determined

Lumped Parameter Modeling for Rapid Vibration Response Prototyping and Test Correlation for Electronic Units

Science.gov (United States)

Van Dyke, Michael B.

2013-01-01

Present preliminary work using lumped parameter models to approximate dynamic response of electronic units to random vibration; Derive a general N-DOF model for application to electronic units; Illustrate parametric influence of model parameters; Implication of coupled dynamics for unit/board design; Demonstrate use of model to infer printed wiring board (PWB) dynamics from external chassis test measurement.

Analysis of transient heat conduction in a PWR fuel rod by an improved lumped parameter approach

Energy Technology Data Exchange (ETDEWEB)

Dourado, Eneida Regina G. [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil); Cotta, Renato M. [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Mecanica; Jian, Su, E-mail: eneidadourado@gmail.com, E-mail: sujian@nuclear.ufrj.br, E-mail: cotta@mecanica.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

2017-07-01

This paper aims to analyze transient heat conduction in a nuclear fuel rod by an improved lumped parameter approach. One-dimensional transient heat conduction is considered, with the circumferential symmetry assumed and the axial conduction neglected. The thermal conductivity and specific heat in the fuel pellet are considered temperature dependent, while the thermophysical properties of the cladding are considered constant. Hermite approximation for integration is used to obtain the average temperature and heat flux in the radial direction. Significant improvement over the classical lumped parameter formulation has been achieved. The proposed model can be also used in dynamic analysis of PWR and nuclear power plant simulators. (author)

Analysis of transient heat conduction in a PWR fuel rod by an improved lumped parameter approach

International Nuclear Information System (INIS)

Dourado, Eneida Regina G.; Cotta, Renato M.; Jian, Su

2017-01-01

This paper aims to analyze transient heat conduction in a nuclear fuel rod by an improved lumped parameter approach. One-dimensional transient heat conduction is considered, with the circumferential symmetry assumed and the axial conduction neglected. The thermal conductivity and specific heat in the fuel pellet are considered temperature dependent, while the thermophysical properties of the cladding are considered constant. Hermite approximation for integration is used to obtain the average temperature and heat flux in the radial direction. Significant improvement over the classical lumped parameter formulation has been achieved. The proposed model can be also used in dynamic analysis of PWR and nuclear power plant simulators. (author)

Lumped-parameter modeling of PWR downcomer and pressurizer for LOCA conditions

International Nuclear Information System (INIS)

Rohatgi, U.S.; Saha, P.; Dubow, A.A.

1978-01-01

Two lumped-parameter models, one for a PWR downcomer and the other for a pressurizer, are presented. The models are based on the transient, nonhomogeneous, drift-flux description of two-phase flow, and are suitable for simulating a hypothetical LOCA condition. Effects of thermal nonequilibrium are incorporated in the downcomer model, whereas the pressurizer model can track the interfaces among various flow regimes. Semiimplicit numerical schemes are used for solution. Encouraging results have been obtained for both the models. (author)

Lumped Parameter Models of the Central Nervous System for VIIP Research

Science.gov (United States)

Vera, J.; Mulugeta, L.; Nelson, E. S.; Raykin, J.; Feola, A.; Gleason, R.; Samuels, B.; Myers, J. G.

2015-01-01

INTRODUCTION: Current long-duration missions to the International Space Station and future exploration-class missions beyond low-Earth orbit, such as to Mars and asteroids, expose astronauts to increased risk of Visual Impairment and Intracranial Pressure (VIIP) syndrome [1]. It has been hypothesized that the headward shift of cerebral spinal fluid (CSF) and blood in microgravity may cause significant elevation of intracranial pressure (ICP), which in turn induces VIIP syndrome through biomechanical pathways [1, 2]. However, there is insufficient evidence to confirm this hypothesis. In this light, we are developing lumped-parameter models of fluid transport in the central nervous system (CNS) as a means to simulate the influence of microgravity on ICP. The CNS models will also be used in concert with the lumped parameter and finite element models of the eye described in the realted IWS abstracts submitted by Nelson et al., Feola et al. and Ethier et al. METHODS: We have developed a nine compartment CNS model (Figure 1) capable of both time-dependent and steady state fluid transport simulations, based on the works of Stevens et al. [3]. The breakdown of compartments within the model includes: vascular (3), CSF (2), brain (1) and extracranial (3). The boundary pressure in the Central Arteries [A] node is prescribed using an oscillating pressure function PA(t) simulating the carotid pulsatile pressure wave as developed by Linninger et al. [4]. For each time step, pressures are integrated through time using an adaptive-timestep 4th and 5th order Runga-Kutta solver. Once pressures are found, constitutive equations are used to solve for flowrates (Q) between each compartment. In addition to fluid flow between the different compartments, compliance (C) interactions between neighboring compartments are represented. We are also developing a second CNS model based on the works of Linninger et al. [4] which takes a more granular approach to represent the interactions of the

A lumped parameter, low dimension model of heat exchanger

International Nuclear Information System (INIS)

Kanoh, Hideaki; Furushoo, Junji; Masubuchi, Masami

1980-01-01

This paper reports on the results of investigation of the distributed parameter model, the difference model, and the model of the method of weighted residuals for heat exchangers. By the method of weighted residuals (MWR), the opposite flow heat exchanger system is approximated by low dimension, lumped parameter model. By assuming constant specific heat, constant density, the same form of tube cross-section, the same form of the surface of heat exchange, uniform flow velocity, the linear relation of heat transfer to flow velocity, liquid heat carrier, and the thermal insulation of liquid from outside, fundamental equations are obtained. The experimental apparatus was made of acrylic resin. The response of the temperature at the exit of first liquid to the variation of the flow rate of second liquid was measured and compared with the models. The MWR model shows good approximation for the low frequency region, and as the number of division increases, good approximation spreads to higher frequency region. (Kato, T.)

Lumped parameter modeling of a two-phase thermal-hydraulic channel with interface tracking

International Nuclear Information System (INIS)

Jo, J.H.; Kaufman, J.M.; Ruger, C.J.; Stein, S.

1978-01-01

A nonhomogenous, thermal nonequilibrium model for one-dimensional two-phase flow in a heated channel has been formulated in lumped parameter form. The channel is divided into a variable number of flow regimes separated by moving interfaces. The model can be used to predict the behavior of a LWR core and both primary and secondary sides of a steam generator under transient conditions. (author)

Lump solutions to the Kadomtsev–Petviashvili equation

Energy Technology Data Exchange (ETDEWEB)

Ma, Wen-Xiu, E-mail: mawx@cas.usf.edu

2015-09-25

Through symbolic computation with Maple, a class of lump solutions, rationally localized in all directions in the space, to the (2 + 1)-dimensional Kadomtsev–Petviashvili (KP) equation is presented, making use of its Hirota bilinear form. The resulting lump solutions contain six free parameters, two of which are due to the translation invariance of the KP equation and the other four of which satisfy a non-zero determinant condition guaranteeing analyticity and rational localization of the solutions. Three contour plots with different determinant values are sequentially made to show that the corresponding lump solution tends to zero when the determinant approaches zero. Two particular lump solutions with specific values of the involved parameters are plotted, as illustrative examples. - Highlights: • Positive quadratic function solutions. • Solitons rationally-localized in all directions in the space. • Solving systems of nonlinear algebraic equations by symbolic computation with Maple.

Measurement of Hydrologic Streamflow Metrics and Estimation of Streamflow with Lumped Parameter Models in a Managed Lake System, Sebago Lake, Maine

Science.gov (United States)

Reeve, A. S.; Martin, D.; Smith, S. M.

2013-12-01

Surface waters within the Sebago Lake watershed (southern Maine, USA) provide a variety of economically and intrinsically valuable recreational, commercial and environmental services. Different stakeholder groups for the 118 km2 Sebago Lake and surrounding watershed advocate for different lake and watershed management strategies, focusing on the operation of a dam at the outflow from Sebago Lake. While lake level in Sebago Lake has been monitored for over a century, limited data is available on the hydrologic processes that drive lake level and therefore impact how dam operation (and other changes to the region) will influence the hydroperiod of the lake. To fill this information gap several tasks were undertaken including: 1) deploying data logging pressure transducers to continuously monitor stream stage in nine tributaries, 2) measuring stream discharge at these sites to create rating curves for the nine tributaries, and using the resulting continuous discharge records to 3) calibrate lumped parameter computer models based on the GR4J model, modified to include a degree-day snowmelt routine. These lumped parameter models have been integrated with a simple lake water-balance model to estimate lake level and its response to different scenarios including dam management strategies. To date, about three years of stream stage data have been used to estimate stream discharge in all monitored tributaries (data collection is ongoing). Baseflow separation indices (BFI) for 2010 and 2011 using the USGS software PART and the Eckhart digital filter in WHAT range from 0.80-0.86 in the Crooked River and Richmill Outlet,followed by Northwest (0.75) and Muddy (0.53-0.56) Rivers, with the lowest BFI measured in Sticky River (0.41-0.56). The BFI values indicate most streams have significant groundwater (or other storage) inputs. The lumped parameter watershed model has been calibrated for four streams (Nash-Sutcliffe = 0.4 to 0.9), with the other major tributaries containing

The application of model with lumped parameters for transient condition analyses of NPP

International Nuclear Information System (INIS)

Stankovic, B.; Stevanovic, V.

1985-01-01

The transient behaviour of NPP Krsko during the accident of pressurizer spray valve stuck open has been simulated y lumped parameters model of the PWR coolant system components, developed at the faculty of Mechanical Engineering, University of Belgrade. The elementary volumes which are characterised by the process and state parameters, and by junctions which are characterised by the geometrical and flow parameters are basic structure of physical model. The process parameters obtained by the model RESI, show qualitative agreement with the measured valves, in a degree in which the actions of reactor safety engineered system and emergency core cooling system are adequately modelled; in spite of the elementary physical model structure and only the modelling of thermal process in reactor core and equilibrium conditions of pressurizer and steam generator. The pressurizer pressure and liquid level predicted by the non-equilibrium pressurizer model SOP show good agreement until the HIPS (high pressure pumps) is activated. (author)

MEMS 3-DoF gyroscope design, modeling and simulation through equivalent circuit lumped parameter model

International Nuclear Information System (INIS)

Mian, Muhammad Umer; Khir, M. H. Md.; Tang, T. B.; Dennis, John Ojur; Riaz, Kashif; Iqbal, Abid; Bazaz, Shafaat A.

2015-01-01

Pre-fabrication, behavioural and performance analysis with computer aided design (CAD) tools is a common and fabrication cost effective practice. In light of this we present a simulation methodology for a dual-mass oscillator based 3 Degree of Freedom (3-DoF) MEMS gyroscope. 3-DoF Gyroscope is modeled through lumped parameter models using equivalent circuit elements. These equivalent circuits consist of elementary components which are counterpart of their respective mechanical components, used to design and fabricate 3-DoF MEMS gyroscope. Complete designing of equivalent circuit model, mathematical modeling and simulation are being presented in this paper. Behaviors of the equivalent lumped models derived for the proposed device design are simulated in MEMSPRO T-SPICE software. Simulations are carried out with the design specifications following design rules of the MetalMUMPS fabrication process. Drive mass resonant frequencies simulated by this technique are 1.59 kHz and 2.05 kHz respectively, which are close to the resonant frequencies found by the analytical formulation of the gyroscope. The lumped equivalent circuit modeling technique proved to be a time efficient modeling technique for the analysis of complex MEMS devices like 3-DoF gyroscopes. The technique proves to be an alternative approach to the complex and time consuming couple field analysis Finite Element Analysis (FEA) previously used

MEMS 3-DoF gyroscope design, modeling and simulation through equivalent circuit lumped parameter model

Energy Technology Data Exchange (ETDEWEB)

Mian, Muhammad Umer, E-mail: umermian@gmail.com; Khir, M. H. Md.; Tang, T. B. [Department of Electrical and Electronic Engineering, Universiti Teknologi PETRONAS, Tronoh, Perak (Malaysia); Dennis, John Ojur [Department of Fundamental & Applied Sciences, Universiti Teknologi PETRONAS, Tronoh, Perak (Malaysia); Riaz, Kashif; Iqbal, Abid [Faculty of Electronics Engineering, GIK Institute of Engineering Sciences and Technology, Topi, Khyber Pakhtunkhaw (Pakistan); Bazaz, Shafaat A. [Department of Computer Science, Center for Advance Studies in Engineering, Islamabad (Pakistan)

2015-07-22

Pre-fabrication, behavioural and performance analysis with computer aided design (CAD) tools is a common and fabrication cost effective practice. In light of this we present a simulation methodology for a dual-mass oscillator based 3 Degree of Freedom (3-DoF) MEMS gyroscope. 3-DoF Gyroscope is modeled through lumped parameter models using equivalent circuit elements. These equivalent circuits consist of elementary components which are counterpart of their respective mechanical components, used to design and fabricate 3-DoF MEMS gyroscope. Complete designing of equivalent circuit model, mathematical modeling and simulation are being presented in this paper. Behaviors of the equivalent lumped models derived for the proposed device design are simulated in MEMSPRO T-SPICE software. Simulations are carried out with the design specifications following design rules of the MetalMUMPS fabrication process. Drive mass resonant frequencies simulated by this technique are 1.59 kHz and 2.05 kHz respectively, which are close to the resonant frequencies found by the analytical formulation of the gyroscope. The lumped equivalent circuit modeling technique proved to be a time efficient modeling technique for the analysis of complex MEMS devices like 3-DoF gyroscopes. The technique proves to be an alternative approach to the complex and time consuming couple field analysis Finite Element Analysis (FEA) previously used.

MISTRA facility for containment lumped parameter and CFD codes validation. Example of the International Standard Problem ISP47

International Nuclear Information System (INIS)

Tkatschenko, I.; Studer, E.; Paillere, H.

2005-01-01

During a severe accident in a Pressurized Water Reactor (PWR), the formation of a combustible gas mixture in the complex geometry of the reactor depends on the understanding of hydrogen production, the complex 3D thermal-hydraulics flow due to gas/steam injection, natural convection, heat transfer by condensation on walls and effect of mitigation devices. Numerical simulation of such flows may be performed either by Lumped Parameter (LP) or by Computational Fluid Dynamics (CFD) codes. Advantages and drawbacks of LP and CFD codes are well-known. LP codes are mainly developed for full size containment analysis but they need improvements, especially since they are not able to accurately predict the local gas mixing within the containment. CFD codes require a process of validation on well-instrumented experimental data before they can be used with a high degree of confidence. The MISTRA coupled effect test facility has been built at CEA to fulfil this validation objective: with numerous measurement points in the gaseous volume - temperature, gas concentration, velocity and turbulence - and with well controlled boundary conditions. As illustration of both experimental and simulation areas of this topic, a recent example in the use of MISTRA test data is presented for the case of the International Standard Problem ISP47. The proposed experimental work in the MISTRA facility provides essential data to fill the gaps in the modelling/validation of computational tools. (author)

Revisiting Appendicular Lump

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R S Bhandari

2010-06-01

Full Text Available INTRODUCTION: Appendicular lump is a well known sequalae of acute appendicitis encountered in 2-6% of patients. Successful management of appendicular lump is controversial with different approaches. As many controversies are arising regarding management of appendicular lump. The aim of this study was to find out the outcome and evaluate possible need of changing our management strategy of appendicular lump. METHODS: A retrospective analysis of the patients managed with appendicular lump were done. All the patients admitted with diagnosis of appendicular lump and managed between, over two and half years, were included in the study. All age groups and both sex were included. Any patients whose diagnosis was changed after initial diagnosis of appendicular lump were excluded from the study. RESULTS: Total 75 patients had appendicular lump suggesting 10% incidence. Age varied between 11-83 years with nearly equal incidence in both sexes. Majority had onset of symptoms between 2 to 14 days with an average of 4 days. Average stay was 3 to 4 days. During study period, 12 (16% came with recurrence and 13 (17% cases came for elective appendectomy. CONCLUSIONS: Based on our finding, it is not sufficient to change our classical management strategy of appendicular lump and suggests a need for long term prospective study in this very common clinical condition. KEYWORDS: appendicular lump, conservative management.

Revisiting appendicular lump.

Science.gov (United States)

Bhandari, R S; Thakur, D K; Lakhey, P J; Singh, K P

2010-01-01

Appendicular lump is a well known sequalae of acute appendicitis encountered in 2-6% of patients. Successful management of appendicular lump is controversial with different approaches. As many controversies are arising regarding management of appendicular lump. The aim of this study was to find out the outcome and evaluate possible need of changing our management strategy of appendicular lump. A retrospective analysis of the patients managed with appendicular lump were done. All the patients admitted with diagnosis of appendicular lump and managed between, over two and half years, were included in the study. All age groups and both sex were included. Any patients whose diagnosis was changed after initial diagnosis of appendicular lump were excluded from the study. Total 75 patients had appendicular lump suggesting 10% incidence. Age varied between 11-83 years with nearly equal incidence in both sexes. Majority had onset of symptoms between 2 to 14 days with an average of 4 days. Average stay was 3 to 4 days. During study period, 12 (16%) came with recurrence and 13 (17%) cases came for elective appendectomy. Based on our finding, it is not sufficient to change our classical management strategy of appendicular lump and suggests a need for long term prospective study in this very common clinical condition.

Lump wood combustion process

Science.gov (United States)

Kubesa, Petr; Horák, Jiří; Branc, Michal; Krpec, Kamil; Hopan, František; Koloničný, Jan; Ochodek, Tadeáš; Drastichová, Vendula; Martiník, Lubomír; Malcho, Milan

2014-08-01

The article deals with the combustion process for lump wood in low-power fireplaces (units to dozens of kW). Such a combustion process is cyclical in its nature, and what combustion facility users are most interested in is the frequency, at which fuel needs to be stoked to the fireplace. The paper defines the basic terms such as burnout curve and burning rate curve, which are closely related to the stocking frequency. The fuel burning rate is directly dependent on the immediate thermal power of the fireplace. This is also related to the temperature achieved in the fireplace, magnitude of flue gas losses and the ability to generate conditions favouring the full burnout of the fuel's combustible component, which, at once ensures the minimum production of combustible pollutants. Another part of the paper describes experiments conducted in traditional fireplaces with a grate, at which well-dried lump wood was combusted.

Lumped parametric model of the human ear for sound transmission.

Science.gov (United States)

Feng, Bin; Gan, Rong Z

2004-09-01

A lumped parametric model of the human auditoria peripherals consisting of six masses suspended with six springs and ten dashpots was proposed. This model will provide the quantitative basis for the construction of a physical model of the human middle ear. The lumped model parameters were first identified using published anatomical data, and then determined through a parameter optimization process. The transfer function of the middle ear obtained from human temporal bone experiments with laser Doppler interferometers was used for creating the target function during the optimization process. It was found that, among 14 spring and dashpot parameters, there were five parameters which had pronounced effects on the dynamic behaviors of the model. The detailed discussion on the sensitivity of those parameters was provided with appropriate applications for sound transmission in the ear. We expect that the methods for characterizing the lumped model of the human ear and the model parameters will be useful for theoretical modeling of the ear function and construction of the ear physical model.

Improved lumped models for transient combined convective and radiative cooling of a two-layer spherical fuel element

International Nuclear Information System (INIS)

Silva, Alice Cunha da; Su, Jian

2013-01-01

The High Temperature Gas cooled Reactor (HTGR) is a fourth generation thermal nuclear reactor, graphite-moderated and helium cooled. The HTGRs have important characteristics making essential the study of these reactors, as well as its fuel element. Examples of these are: high thermal efficiency,low operating costs and construction, passive safety attributes that allow implication of the respective plants. The Pebble Bed Modular Reactor (PBMR) is a HTGR with spherical fuel elements that named the reactor. This fuel element is composed by a particulate region with spherical inclusions, the fuel UO2 particles, dispersed in a graphite matrix and a convective heat transfer by Helium happens on the outer surface of the fuel element. In this work, the transient heat conduction in a spherical fuel element of a pebble-bed high temperature reactor was studied in a transient situation of combined convective and radiative cooling. Improved lumped parameter model was developed for the transient heat conduction in the two-layer composite sphere subjected to combined convective and radiative cooling. The improved lumped model was obtained through two-point Hermite approximations for integrals. Transient combined convective and radiative cooling of the two-layer spherical fuel element was analyzed to illustrate the applicability of the proposed lumped model, with respect to die rent values of the Biot number, the radiation-conduction parameter, the dimensionless thermal contact resistance, the dimensionless inner diameter and coating thickness, and the dimensionless thermal conductivity. It was shown by comparison with numerical solution of the original distributed parameter model that the improved lumped model, with H2,1/H1,1/H0,0 approximation yielded significant improvement of average temperature prediction over the classical lumped model. (author)

Rigorous theoretical derivation of lumped models to transmission line systems

International Nuclear Information System (INIS)

Zhao Jixiang

2012-01-01

By virtue of the negative electric parameter concept, i.e. negative lumped resistance, inductance, conductance and capacitance (N-RLGC), the lumped equivalent models of transmission line systems, including the circuit model, two-port π-network and T-network, are given. We start from the N-segment-ladder-like equivalent networks composed distributed parameters, and achieve the input impedance in the form of a continued fraction. Utilizing the continued fraction theory, the expressions of input impedance are obtained under three kinds of extreme cases, i.e. the load impedances are equal to zero, infinity and characteristic impedance, respectively. When the number of segment N is limited to infinity, they are transformed to lumped elements. Comparison between the distributed model and lumped model of transmission lines, the expression of tanh γd, which is the key term in the transmission line equations, are obtained by RLGC, furthermore, according to input admittance, admittance matrix and ABCD matrix of transmission lines, the lumped equivalent circuit models, π-networks and T-networks have been given. The models are verified in the frequency and time domain, respectively, showing that the models are accurate and efficient. (semiconductor integrated circuits)

Improved lumped models for transient combined convective and radiative cooling of multi-layer composite slabs

International Nuclear Information System (INIS)

An Chen; Su Jian

2011-01-01

Improved lumped parameter models were developed for the transient heat conduction in multi-layer composite slabs subjected to combined convective and radiative cooling. The improved lumped models were obtained through two-point Hermite approximations for integrals. Transient combined convective and radiative cooling of three-layer composite slabs was analyzed to illustrate the applicability of the proposed lumped models, with respect to different values of the Biot numbers, the radiation-conduction parameter, the dimensionless thermal contact resistances, the dimensionless thickness, and the dimensionless thermal conductivity. It was shown by comparison with numerical solution of the original distributed parameter model that the higher order lumped model (H 1,1 /H 0,0 approximation) yielded significant improvement of average temperature prediction over the classical lumped model. In addition, the higher order (H 1,1 /H 0,0 ) model was applied to analyze the transient heat conduction problem of steel-concrete-steel sandwich plates. - Highlights: → Improved lumped models for convective-radiative cooling of multi-layer slabs were developed. → Two-point Hermite approximations for integrals were employed. → Significant improvement over classical lumped model was achieved. → The model can be applied to high Biot number and high radiation-conduction parameter. → Transient heat conduction in steel-concrete-steel sandwich pipes was analyzed as an example.

Genetic Algorithms for Estimating Effective Parameters in a Lumped Reactor Model for Reactivity Predictions

International Nuclear Information System (INIS)

Marseguerra, Marzio; Zio, Enrico

2001-01-01

The control system of a reactor should be able to predict, in real time, the amount of reactivity to be inserted (e.g., by control rod movements and boron injection and dilution) to respond to a given electrical load demand or to undesired, accidental transients. The real-time constraint renders impractical the use of a large, detailed dynamic reactor code. One has, then, to resort to simplified analytical models with lumped effective parameters suitably estimated from the reactor data.The simple and well-known Chernick model for describing the reactor power evolution in the presence of xenon is considered and the feasibility of using genetic algorithms for estimating the effective nuclear parameters involved and the initial nonmeasurable xenon and iodine conditions is investigated. This approach has the advantage of counterbalancing the inherent model simplicity with the periodic reestimation of the effective parameter values pertaining to each reactor on the basis of its recent history. By so doing, other effects, such as burnup, are automatically taken into account

Lumping procedure for a kinetic model of catalytic naphtha reforming

Directory of Open Access Journals (Sweden)

H. M. Arani

2009-12-01

Full Text Available A lumping procedure is developed for obtaining kinetic and thermodynamic parameters of catalytic naphtha reforming. All kinetic and deactivation parameters are estimated from industrial data and thermodynamic parameters are calculated from derived mathematical expressions. The proposed model contains 17 lumps that include the C6 to C8+ hydrocarbon range and 15 reaction pathways. Hougen-Watson Langmuir-Hinshelwood type reaction rate expressions are used for kinetic simulation of catalytic reactions. The kinetic parameters are benchmarked with several sets of plant data and estimated by the SQP optimization method. After calculation of deactivation and kinetic parameters, plant data are compared with model predictions and only minor deviations between experimental and calculated data are generally observed.

GEYSER/TONUS: a coupled multi-D lumped parameter code for reactor thermal hydraulics analysis in case of severe accidents

Energy Technology Data Exchange (ETDEWEB)

Petit, M.; Durin, M.; Gauvain, J.

1995-12-31

The safety requirements for future light water reactors include accounting for severe accidents in the design process. The design must now include mitigation features to limit pressure and temperature inside the building. Hydrogen concentration is also a major issue for severe accidents. Modelling the thermal hydraulics inside the containment requires the description of complex phenomena such as condensation, stratification, transport of gases and aerosols, heat transfers. The effect of mitigation systems will increase the heterogeneities in the building, and most of those phenomena can be coupled. The GEYSER/TONUS multi-dimensional computer code is under development at CEA Saclay to model this complex situation. It allow the coupling of parts of the containment described in a lumped parameter manner, together with meshed parts. Emphasis is put on the numerical methods used to solve the transient problem, and physical models of classical lumped parameters codes will be adapted for the spatially described zones. The code is developed in the environment of the CASTEM 2000/TRIO EF system which allows to construct sophisticated applications based upon it. (J.S.). 22 refs., 1 fig.

GEYSER/TONUS: a coupled multi-D lumped parameter code for reactor thermal hydraulics analysis in case of severe accidents

International Nuclear Information System (INIS)

Petit, M.; Durin, M.; Gauvain, J.

1995-01-01

The safety requirements for future light water reactors include accounting for severe accidents in the design process. The design must now include mitigation features to limit pressure and temperature inside the building. Hydrogen concentration is also a major issue for severe accidents. Modelling the thermal hydraulics inside the containment requires the description of complex phenomena such as condensation, stratification, transport of gases and aerosols, heat transfers. The effect of mitigation systems will increase the heterogeneities in the building, and most of those phenomena can be coupled. The GEYSER/TONUS multi-dimensional computer code is under development at CEA Saclay to model this complex situation. It allow the coupling of parts of the containment described in a lumped parameter manner, together with meshed parts. Emphasis is put on the numerical methods used to solve the transient problem, and physical models of classical lumped parameters codes will be adapted for the spatially described zones. The code is developed in the environment of the CASTEM 2000/TRIO EF system which allows to construct sophisticated applications based upon it. (J.S.). 22 refs., 1 fig

Lump solutions with interaction phenomena in the (2+1)-dimensional Ito equation

Science.gov (United States)

Zou, Li; Yu, Zong-Bing; Tian, Shou-Fu; Feng, Lian-Li; Li, Jin

2018-03-01

In this paper, we consider the (2+1)-dimensional Ito equation, which was introduced by Ito. By considering the Hirota’s bilinear method, and using the positive quadratic function, we obtain some lump solutions of the Ito equation. In order to ensure rational localization and analyticity of these lump solutions, some sufficient and necessary conditions are provided on the parameters that appeared in the solutions. Furthermore, the interaction solutions between lump solutions and the stripe solitons are discussed by combining positive quadratic function with exponential function. Finally, the dynamic properties of these solutions are shown via the way of graphical analysis by selecting appropriate values of the parameters.

Parameter sensitivity analysis of a lumped-parameter model of a chain of lymphangions in series.

Science.gov (United States)

Jamalian, Samira; Bertram, Christopher D; Richardson, William J; Moore, James E

2013-12-01

Any disruption of the lymphatic system due to trauma or injury can lead to edema. There is no effective cure for lymphedema, partly because predictive knowledge of lymphatic system reactions to interventions is lacking. A well-developed model of the system could greatly improve our understanding of its function. Lymphangions, defined as the vessel segment between two valves, are the individual pumping units. Based on our previous lumped-parameter model of a chain of lymphangions, this study aimed to identify the parameters that affect the system output the most using a sensitivity analysis. The system was highly sensitive to minimum valve resistance, such that variations in this parameter caused an order-of-magnitude change in time-average flow rate for certain values of imposed pressure difference. Average flow rate doubled when contraction frequency was increased within its physiological range. Optimum lymphangion length was found to be some 13-14.5 diameters. A peak of time-average flow rate occurred when transmural pressure was such that the pressure-diameter loop for active contractions was centered near maximum passive vessel compliance. Increasing the number of lymphangions in the chain improved the pumping in the presence of larger adverse pressure differences. For a given pressure difference, the optimal number of lymphangions increased with the total vessel length. These results indicate that further experiments to estimate valve resistance more accurately are necessary. The existence of an optimal value of transmural pressure may provide additional guidelines for increasing pumping in areas affected by edema.

Development of a transient, lumped hydrologic model for geomorphologic units in a geomorphology based rainfall-runoff modelling framework

Science.gov (United States)

Vannametee, E.; Karssenberg, D.; Hendriks, M. R.; de Jong, S. M.; Bierkens, M. F. P.

2010-05-01

We propose a modelling framework for distributed hydrological modelling of 103-105 km2 catchments by discretizing the catchment in geomorphologic units. Each of these units is modelled using a lumped model representative for the processes in the unit. Here, we focus on the development and parameterization of this lumped model as a component of our framework. The development of the lumped model requires rainfall-runoff data for an extensive set of geomorphological units. Because such large observational data sets do not exist, we create artificial data. With a high-resolution, physically-based, rainfall-runoff model, we create artificial rainfall events and resulting hydrographs for an extensive set of different geomorphological units. This data set is used to identify the lumped model of geomorphologic units. The advantage of this approach is that it results in a lumped model with a physical basis, with representative parameters that can be derived from point-scale measurable physical parameters. The approach starts with the development of the high-resolution rainfall-runoff model that generates an artificial discharge dataset from rainfall inputs as a surrogate of a real-world dataset. The model is run for approximately 105 scenarios that describe different characteristics of rainfall, properties of the geomorphologic units (i.e. slope gradient, unit length and regolith properties), antecedent moisture conditions and flow patterns. For each scenario-run, the results of the high-resolution model (i.e. runoff and state variables) at selected simulation time steps are stored in a database. The second step is to develop the lumped model of a geomorphological unit. This forward model consists of a set of simple equations that calculate Hortonian runoff and state variables of the geomorphologic unit over time. The lumped model contains only three parameters: a ponding factor, a linear reservoir parameter, and a lag time. The model is capable of giving an appropriate

Deducing Electronic Unit Internal Response During a Vibration Test Using a Lumped Parameter Modeling Approach

Science.gov (United States)

Van Dyke, Michael B.

2014-01-01

During random vibration testing of electronic boxes there is often a desire to know the dynamic response of certain internal printed wiring boards (PWBs) for the purpose of monitoring the response of sensitive hardware or for post-test forensic analysis in support of anomaly investigation. Due to restrictions on internally mounted accelerometers for most flight hardware there is usually no means to empirically observe the internal dynamics of the unit, so one must resort to crude and highly uncertain approximations. One common practice is to apply Miles Equation, which does not account for the coupled response of the board in the chassis, resulting in significant over- or under-prediction. This paper explores the application of simple multiple-degree-of-freedom lumped parameter modeling to predict the coupled random vibration response of the PWBs in their fundamental modes of vibration. A simple tool using this approach could be used during or following a random vibration test to interpret vibration test data from a single external chassis measurement to deduce internal board dynamics by means of a rapid correlation analysis. Such a tool might also be useful in early design stages as a supplemental analysis to a more detailed finite element analysis to quickly prototype and analyze the dynamics of various design iterations. After developing the theoretical basis, a lumped parameter modeling approach is applied to an electronic unit for which both external and internal test vibration response measurements are available for direct comparison. Reasonable correlation of the results demonstrates the potential viability of such an approach. Further development of the preliminary approach presented in this paper will involve correlation with detailed finite element models and additional relevant test data.

Causes of breast lumps (image)

Science.gov (United States)

... breast lumps are benign (non-cancerous), as in fibroadenoma, a condition that mostly affects women under age ... with the menstrual cycle, whereas a lump from fibroadenoma does not. While most breast lumps are benign, ...

Dark lump excitations in superfluid Fermi gases

Science.gov (United States)

Xu, Yan-Xia; Duan, Wen-Shan

2012-11-01

We study the linear and nonlinear properties of two-dimensional matter-wave pulses in disk-shaped superfluid Fermi gases. A Kadomtsev—Petviashvili I (KPI) solitary wave has been realized for superfluid Fermi gases in the limited cases of Bardeen—Cooper—Schrieffer (BCS) regime, Bose—Einstein condensate (BEC) regime, and unitarity regime. One-lump solution as well as one-line soliton solutions for the KPI equation are obtained, and two-line soliton solutions with the same amplitude are also studied in the limited cases. The dependence of the lump propagating velocity and the sound speed of two-dimensional superfluid Fermi gases on the interaction parameter are investigated for the limited cases of BEC and unitarity.

Dark lump excitations in superfluid Fermi gases

International Nuclear Information System (INIS)

Xu Yan-Xia; Duan Wen-Shan

2012-01-01

We study the linear and nonlinear properties of two-dimensional matter-wave pulses in disk-shaped superfluid Fermi gases. A Kadomtsev—Petviashvili I (KPI) solitary wave has been realized for superfluid Fermi gases in the limited cases of Bardeen—Cooper—Schrieffer (BCS) regime, Bose—Einstein condensate (BEC) regime, and unitarity regime. One-lump solution as well as one-line soliton solutions for the KPI equation are obtained, and two-line soliton solutions with the same amplitude are also studied in the limited cases. The dependence of the lump propagating velocity and the sound speed of two-dimensional superfluid Fermi gases on the interaction parameter are investigated for the limited cases of BEC and unitarity

A new lumped-parameter approach to simulating flow processes in unsaturated dual-porosity media

Energy Technology Data Exchange (ETDEWEB)

Zimmerman, R.W.; Hadgu, T.; Bodvarsson, G.S. [Lawrence Berkeley Laboratory, CA (United States)

1995-03-01

We have developed a new lumped-parameter dual-porosity approach to simulating unsaturated flow processes in fractured rocks. Fluid flow between the fracture network and the matrix blocks is described by a nonlinear equation that relates the imbibition rate to the local difference in liquid-phase pressure between the fractures and the matrix blocks. This equation is a generalization of the Warren-Root equation, but unlike the Warren-Root equation, is accurate in both the early and late time regimes. The fracture/matrix interflow equation has been incorporated into a computational module, compatible with the TOUGH simulator, to serve as a source/sink term for fracture elements. The new approach achieves accuracy comparable to simulations in which the matrix blocks are discretized, but typically requires an order of magnitude less computational time.

BWR MARK I pressure suppression pool mixing and stratification analysis using GOTHIC lumped parameter modeling methodology

International Nuclear Information System (INIS)

Ozdemir, Ozkan Emre; George, Thomas L.

2015-01-01

As a part of the GOTHIC (GOTHIC incorporates technology developed for the electric power industry under the sponsorship of EPRI.) Fukushima Technical Evaluation project (EPRI, 2014a, b, 2015), GOTHIC (EPRI, 2014c) has been benchmarked against test data for pool stratification (EPRI, 2014a, b, Ozdemir and George, 2013). These tests confirmed GOTHIC’s ability to simulate pool mixing and stratification under a variety of anticipated suppression pool operating conditions. The multidimensional modeling requires long simulation times for events that may occur over a period of hours or days. For these scenarios a lumped model of the pressure suppression chamber is desirable to maintain reasonable simulation times. However, a lumped model for the pool is not able to predict the effects of pool stratification that can influence the overall containment response. The main objective of this work is on the development of a correlation that can be used to estimate pool mixing and stratification effects in a lumped modeling approach. A simplified lumped GOTHIC model that includes a two zone model for the suppression pool with controlled circulation between the upper and lower zones was constructed. A pump and associated flow connections are included to provide mixing between the upper and lower pool volumes. Using numerically generated data from a multidimensional GOTHIC model for the suppression pool, a correlation was developed for the mixing rate between the upper and lower pool volumes in a two-zone, lumped model. The mixing rate depends on the pool subcooling, the steam injection rate and the injection depth

Application of Biologically-Based Lumping To Investigate the ...

Science.gov (United States)

People are often exposed to complex mixtures of environmental chemicals such as gasoline, tobacco smoke, water contaminants, or food additives. However, investigators have often considered complex mixtures as one lumped entity. Valuable information can be obtained from these experiments, though this simplification provides little insight into the impact of a mixture's chemical composition on toxicologically-relevant metabolic interactions that may occur among its constituents. We developed an approach that applies chemical lumping methods to complex mixtures, in this case gasoline, based on biologically relevant parameters used in physiologically-based pharmacokinetic (PBPK) modeling. Inhalation exposures were performed with rats to evaluate performance of our PBPK model. There were 109 chemicals identified and quantified in the vapor in the chamber. The time-course kinetic profiles of 10 target chemicals were also determined from blood samples collected during and following the in vivo experiments. A general PBPK model was used to compare the experimental data to the simulated values of blood concentration for the 10 target chemicals with various numbers of lumps, iteratively increasing from 0 to 99. Large reductions in simulation error were gained by incorporating enzymatic chemical interactions, in comparison to simulating the individual chemicals separately. The error was further reduced by lumping the 99 non-target chemicals. Application of this biologic

A lumped parameter method of characteristics approach and multigroup kernels applied to the subgroup self-shielding calculation in MPACT

International Nuclear Information System (INIS)

Stimpson, Shane G.; Liu, Yuxuan; Collins, Benjamin S.; Clarno, Kevin T.

2017-01-01

An essential component of the neutron transport solver is the resonance self-shielding calculation used to determine equivalence cross sections. The neutron transport code, MPACT, is currently using the subgroup self-shielding method, in which the method of characteristics (MOC) is used to solve purely absorbing fixed-source problems. Recent efforts incorporating multigroup kernels to the MOC solvers in MPACT have reduced runtime by roughly 2×. Applying the same concepts for self-shielding and developing a novel lumped parameter approach to MOC, substantial improvements have also been made to the self-shielding computational efficiency without sacrificing any accuracy. These new multigroup and lumped parameter capabilities have been demonstrated on two test cases: (1) a single lattice with quarter symmetry known as VERA (Virtual Environment for Reactor Applications) Progression Problem 2a and (2) a two-dimensional quarter-core slice known as Problem 5a-2D. From these cases, self-shielding computational time was reduced by roughly 3–4×, with a corresponding 15–20% increase in overall memory burden. An azimuthal angle sensitivity study also shows that only half as many angles are needed, yielding an additional speedup of 2×. In total, the improvements yield roughly a 7–8× speedup. Furthermore given these performance benefits, these approaches have been adopted as the default in MPACT.

A lumped parameter method of characteristics approach and multigroup kernels applied to the subgroup self-shielding calculation in MPACT

Directory of Open Access Journals (Sweden)

Shane Stimpson

2017-09-01

Full Text Available An essential component of the neutron transport solver is the resonance self-shielding calculation used to determine equivalence cross sections. The neutron transport code, MPACT, is currently using the subgroup self-shielding method, in which the method of characteristics (MOC is used to solve purely absorbing fixed-source problems. Recent efforts incorporating multigroup kernels to the MOC solvers in MPACT have reduced runtime by roughly 2×. Applying the same concepts for self-shielding and developing a novel lumped parameter approach to MOC, substantial improvements have also been made to the self-shielding computational efficiency without sacrificing any accuracy. These new multigroup and lumped parameter capabilities have been demonstrated on two test cases: (1 a single lattice with quarter symmetry known as VERA (Virtual Environment for Reactor Applications Progression Problem 2a and (2 a two-dimensional quarter-core slice known as Problem 5a-2D. From these cases, self-shielding computational time was reduced by roughly 3–4×, with a corresponding 15–20% increase in overall memory burden. An azimuthal angle sensitivity study also shows that only half as many angles are needed, yielding an additional speedup of 2×. In total, the improvements yield roughly a 7–8× speedup. Given these performance benefits, these approaches have been adopted as the default in MPACT.

A new analytical method for estimating lumped parameter constants of linear viscoelastic models from strain rate tests

Science.gov (United States)

Mattei, G.; Ahluwalia, A.

2018-04-01

We introduce a new function, the apparent elastic modulus strain-rate spectrum, E_{app} ( \\dot{ɛ} ), for the derivation of lumped parameter constants for Generalized Maxwell (GM) linear viscoelastic models from stress-strain data obtained at various compressive strain rates ( \\dot{ɛ}). The E_{app} ( \\dot{ɛ} ) function was derived using the tangent modulus function obtained from the GM model stress-strain response to a constant \\dot{ɛ} input. Material viscoelastic parameters can be rapidly derived by fitting experimental E_{app} data obtained at different strain rates to the E_{app} ( \\dot{ɛ} ) function. This single-curve fitting returns similar viscoelastic constants as the original epsilon dot method based on a multi-curve global fitting procedure with shared parameters. Its low computational cost permits quick and robust identification of viscoelastic constants even when a large number of strain rates or replicates per strain rate are considered. This method is particularly suited for the analysis of bulk compression and nano-indentation data of soft (bio)materials.

Impact of atrial fibrillation on the cardiovascular system through a lumped-parameter approach.

Science.gov (United States)

Scarsoglio, Stefania; Guala, Andrea; Camporeale, Carlo; Ridolfi, Luca

2014-11-01

Atrial fibrillation (AF) is the most common arrhythmia affecting millions of people in the Western countries and, due to the widespread impact on the population and its medical relevance, is largely investigated in both clinical and bioengineering sciences. However, some important feedback mechanisms are still not clearly established. The present study aims at understanding the global response of the cardiovascular system during paroxysmal AF through a lumped-parameter approach, which is here performed paying particular attention to the stochastic modeling of the irregular heartbeats and the reduced contractility of the heart. AF can be here analyzed by means of a wide number of hemodynamic parameters and avoiding the presence of other pathologies, which usually accompany AF. Reduced cardiac output with correlated drop of ejection fraction and decreased amount of energy converted to work by the heart during blood pumping, as well as higher left atrial volumes and pressures are some of the most representative results aligned with the existing clinical literature and here emerging during acute AF. The present modeling, providing new insights on cardiovascular variables which are difficult to measure and rarely reported in literature, turns out to be an efficient and powerful tool for a deeper comprehension and prediction of the arrythmia impact on the whole cardiovascular system.

Flexible hydrological modeling - Disaggregation from lumped catchment scale to higher spatial resolutions

Science.gov (United States)

Tran, Quoc Quan; Willems, Patrick; Pannemans, Bart; Blanckaert, Joris; Pereira, Fernando; Nossent, Jiri; Cauwenberghs, Kris; Vansteenkiste, Thomas

2015-04-01

Based on an international literature review on model structures of existing rainfall-runoff and hydrological models, a generalized model structure is proposed. It consists of different types of meteorological components, storage components, splitting components and routing components. They can be spatially organized in a lumped way, or on a grid, spatially interlinked by source-to-sink or grid-to-grid (cell-to-cell) routing. The grid size of the model can be chosen depending on the application. The user can select/change the spatial resolution depending on the needs and/or the evaluation of the accuracy of the model results, or use different spatial resolutions in parallel for different applications. Major research questions addressed during the study are: How can we assure consistent results of the model at any spatial detail? How can we avoid strong or sudden changes in model parameters and corresponding simulation results, when one moves from one level of spatial detail to another? How can we limit the problem of overparameterization/equifinality when we move from the lumped model to the spatially distributed model? The proposed approach is a step-wise one, where first the lumped conceptual model is calibrated using a systematic, data-based approach, followed by a disaggregation step where the lumped parameters are disaggregated based on spatial catchment characteristics (topography, land use, soil characteristics). In this way, disaggregation can be done down to any spatial scale, and consistently among scales. Only few additional calibration parameters are introduced to scale the absolute spatial differences in model parameters, but keeping the relative differences as obtained from the spatial catchment characteristics. After calibration of the spatial model, the accuracies of the lumped and spatial models were compared for peak, low and cumulative runoff total and sub-flows (at downstream and internal gauging stations). For the distributed models, additional

Characterization of an air jet haptic lump display.

Science.gov (United States)

Bianchi, Matteo; Gwilliam, James C; Degirmenci, Alperen; Okamura, Allison M

2011-01-01

During manual palpation, clinicians rely on distributed tactile information to identify and localize hard lumps embedded in soft tissue. The development of tactile feedback systems to enhance palpation using robot-assisted minimally invasive surgery (RMIS) systems is challenging due to size and weight constraints, motivating a pneumatic actuation strategy. Recently, an air jet approach has been proposed for generating a lump percept. We use this technique to direct a thin stream of air through an aperture directly on the finger pad, which indents the skin in a hemispherical manner, producing a compelling lump percept. We hypothesize that the perceived parameters of the lump (e.g. size and stiffness) can be controlled by jointly adjusting air pressure and the aperture size through which air escapes. In this work, we investigate how these control variables interact to affect perceived pressure on the finger pad. First, we used a capacitive tactile sensor array to measure the effect of aperture size on output pressure, and found that peak output pressure increases with aperture size. Second, we performed a psychophysical experiment for each aperture size to determine the just noticeable difference (JND) of air pressure on the finger pad. Subject-averaged pressure JND values ranged from 19.4-24.7 kPa, with no statistical differences observed between aperture sizes. The aperture-pressure relationship and the pressure JND values will be fundamental for future display control.

A partial exponential lumped parameter model to evaluate groundwater age distributions and nitrate trends in long-screened wells

Science.gov (United States)

Jurgens, Bryant; Böhlke, John Karl; Kauffman, Leon J.; Belitz, Kenneth; Esser, Bradley K.

2016-01-01

A partial exponential lumped parameter model (PEM) was derived to determine age distributions and nitrate trends in long-screened production wells. The PEM can simulate age distributions for wells screened over any finite interval of an aquifer that has an exponential distribution of age with depth. The PEM has 3 parameters – the ratio of saturated thickness to the top and bottom of the screen and mean age, but these can be reduced to 1 parameter (mean age) by using well construction information and estimates of the saturated thickness. The PEM was tested with data from 30 production wells in a heterogeneous alluvial fan aquifer in California, USA. Well construction data were used to guide parameterization of a PEM for each well and mean age was calibrated to measured environmental tracer data (3H, 3He, CFC-113, and 14C). Results were compared to age distributions generated for individual wells using advective particle tracking models (PTMs). Age distributions from PTMs were more complex than PEM distributions, but PEMs provided better fits to tracer data, partly because the PTMs did not simulate 14C accurately in wells that captured varying amounts of old groundwater recharged at lower rates prior to groundwater development and irrigation. Nitrate trends were simulated independently of the calibration process and the PEM provided good fits for at least 11 of 24 wells. This work shows that the PEM, and lumped parameter models (LPMs) in general, can often identify critical features of the age distributions in wells that are needed to explain observed tracer data and nonpoint source contaminant trends, even in systems where aquifer heterogeneity and water-use complicate distributions of age. While accurate PTMs are preferable for understanding and predicting aquifer-scale responses to water use and contaminant transport, LPMs can be sensitive to local conditions near individual wells that may be inaccurately represented or missing in an aquifer-scale flow model.

GEYSER/TONUS: A coupled multi-D lumped parameter code for reactor thermal hydraulics analysis in case of severe accidents

Energy Technology Data Exchange (ETDEWEB)

Petit, M.; Durin, M.; Gauvain, J. [Commissariat a l`Energie Atomique, Gif sur Yvette (France)

1995-09-01

In many countries, the safety requirements for future light water reactors include accounting for severe accidents in the design process. As far as the containment is concerned, the design must now include mitigation features to limit the pressure and temperature inside the building. Hydrogen concentration is also a major issue for severe accidents. In this context, new needs appear for the modeling of the thermal hydraulics inside the containment. It requires the description of complex phenomena such as condensation, stratification, transport of gases and aerosols, heat transfers. Moreover, the effect of mitigation systems will increase the heterogeneities in the building, and most of those phenomena can be coupled, as for example hydrogen stratification and condensation. To model such a complex situation, the use of multi-dimensional computer codes seems to be necessary in case of large volumes. The aim of the GEYSER/TONUS computer code is to fulfill this need. This code is currently under development at CEA in Saclay. It will allow the coupling of parts of the containment described in a lumped parameter manner, together with meshed parts. Emphasis is put on the numerical methods used to solve the transient problem, as the objective is to be able to treat complete scenarios. Physical models of classical lumped parameters codes will adapted for the spatially described zones. The code is developed in the environment of the CASTEM 2000/TRIO EF system which allows, thanks to its modular conception, to construct sophisticated applications based upon it.

lumpGEM: Systematic generation of subnetworks and elementally balanced lumped reactions for the biosynthesis of target metabolites.

Directory of Open Access Journals (Sweden)

Meric Ataman

2017-07-01

Full Text Available In the post-genomic era, Genome-scale metabolic networks (GEMs have emerged as invaluable tools to understand metabolic capabilities of organisms. Different parts of these metabolic networks are defined as subsystems/pathways, which are sets of functional roles to implement a specific biological process or structural complex, such as glycolysis and TCA cycle. Subsystem/pathway definition is also employed to delineate the biosynthetic routes that produce biomass building blocks. In databases, such as MetaCyc and SEED, these representations are composed of linear routes from precursors to target biomass building blocks. However, this approach cannot capture the nested, complex nature of GEMs. Here we implemented an algorithm, lumpGEM, which generates biosynthetic subnetworks composed of reactions that can synthesize a target metabolite from a set of defined core precursor metabolites. lumpGEM captures balanced subnetworks, which account for the fate of all metabolites along the synthesis routes, thus encapsulating reactions from various subsystems/pathways to balance these metabolites in the metabolic network. Moreover, lumpGEM collapses these subnetworks into elementally balanced lumped reactions that specify the cost of all precursor metabolites and cofactors. It also generates alternative subnetworks and lumped reactions for the same metabolite, accounting for the flexibility of organisms. lumpGEM is applicable to any GEM and any target metabolite defined in the network. Lumped reactions generated by lumpGEM can be also used to generate properly balanced reduced core metabolic models.

Cytomorphological study of palpable breast lumps

Directory of Open Access Journals (Sweden)

PK Choudhary

2015-09-01

Full Text Available Background: Breast lump is a very common clinical presentation for which fine needle aspiration cytology is often sought for. Because of it’s significant diagnositic value, FNAC has become a routine tool in the evaluation of the nature of the lesion. The objective of this study was to determine the cytomorphological patterns of breast lump in eastern part of Nepal among individuals attending Nobel Medical College. Materials and Methods: This was a retrospective descriptive study done in department of pathology from December 2012 to June 2015. All individuals presenting with breast lumps was included in this study. FNAC was done as per standard procedure and categorized as per United Kingdom National Health Survey Breast Screening Programme (UK-NHS-BSP categories and further also categorized in to neoplastic and non-neolastic categories. Results: We studied 771 cases of breast lumps. Occurrence of breast lump was more common in female (97.4%. Neoplastic lesions accounted for 84.1% of cases out of which benign comprised of 94.6% and malignant comprised of 5.6%. Common benign lesions observed were that of fibroadenona (264 and fibrocystic changes (204. Ductal carcinoma was the most common malignant lesions. All malignant lesions were observed in older age and female sex population.Conclusion: Most of the cases of breast lumps are benign in nature and very few accounted for malignant cases. There is predominance of benign lesions in young age and increased malignancy in older age and female population. 

Rational Solutions and Lump Solutions of the Potential YTSF Equation

Science.gov (United States)

Sun, Hong-Qian; Chen, Ai-Hua

2017-07-01

By using of the bilinear form, rational solutions and lump solutions of the potential Yu-Toda-Sasa-Fukuyama (YTSF) equation are derived. Dynamics of the fundamental lump solution, n1-order lump solutions, and N-lump solutions are studied for some special cases. We also find some interaction behaviours of solitary waves and one lump of rational solutions.

Recomputing Causality Assignments on Lumped Process Models When Adding New Simplification Assumptions

Directory of Open Access Journals (Sweden)

Antonio Belmonte

2018-04-01

Full Text Available This paper presents a new algorithm for the resolution of over-constrained lumped process systems, where partial differential equations of a continuous time and space model of the system are reduced into ordinary differential equations with a finite number of parameters and where the model equations outnumber the unknown model variables. Our proposal is aimed at the study and improvement of the algorithm proposed by Hangos-Szerkenyi-Tuza. This new algorithm improves the computational cost and solves some of the internal problems of the aforementioned algorithm in its original formulation. The proposed algorithm is based on parameter relaxation that can be modified easily. It retains the necessary information of the lumped process system to reduce the time cost after introducing changes during the system formulation. It also allows adjustment of the system formulations that change its differential index between simulations.

7 CFR 1726.205 - Multiparty lump sum quotations.

Science.gov (United States)

2010-01-01

... 7 Agriculture 11 2010-01-01 2010-01-01 false Multiparty lump sum quotations. 1726.205 Section 1726....205 Multiparty lump sum quotations. The borrower or its engineer must contact a sufficient number of... basis of written lump sum quotations, the borrower will select the supplier or contractor based on the...

Intense deuterium nuclear fusion of pycnodeuterium-lumps coagulated locally within highly deuterated atom clusters

CERN Document Server

Yoshiaki, A; Zhang, Y C

2002-01-01

Embedded nano-Pd particles of 5 nm in size instantly abundant D-atoms more than 250% in the atomic ratio against Pd-atoms at room temperature when they are kept in D sub 2 gas pressurized to less than 10 atm. In such ultrahigh densities, 2-4 D-atoms can be coagulated inside each octahedral space of Pd lattice (pycnodeuterium-lump). When a stimulation energy such as latticequake causing by ultrasonic wave was supplied to those highly deuterated Pd particles, intense deuterium nuclear fusion (''solid fusion'') was generated there and both excess heat and sup 4 He gas were abundantly produced. Naturally, these facts can not be realized at all in bulk Pd. The results show that the nuclear fusion occurs without any hazardous rays in pycnodeuterium-lumps coagulated locally inside the each cell of the host metal lattice. These unit cells correspond to minimum unit of the solid fusion reactor as a ''Lattice Reactor''. (author)

Application of Biologically Based Lumping To Investigate the Toxicokinetic Interactions of a Complex Gasoline Mixture.

Science.gov (United States)

Jasper, Micah N; Martin, Sheppard A; Oshiro, Wendy M; Ford, Jermaine; Bushnell, Philip J; El-Masri, Hisham

2016-03-15

People are often exposed to complex mixtures of environmental chemicals such as gasoline, tobacco smoke, water contaminants, or food additives. We developed an approach that applies chemical lumping methods to complex mixtures, in this case gasoline, based on biologically relevant parameters used in physiologically based pharmacokinetic (PBPK) modeling. Inhalation exposures were performed with rats to evaluate the performance of our PBPK model and chemical lumping method. There were 109 chemicals identified and quantified in the vapor in the chamber. The time-course toxicokinetic profiles of 10 target chemicals were also determined from blood samples collected during and following the in vivo experiments. A general PBPK model was used to compare the experimental data to the simulated values of blood concentration for 10 target chemicals with various numbers of lumps, iteratively increasing from 0 to 99. Large reductions in simulation error were gained by incorporating enzymatic chemical interactions, in comparison to simulating the individual chemicals separately. The error was further reduced by lumping the 99 nontarget chemicals. The same biologically based lumping approach can be used to simplify any complex mixture with tens, hundreds, or thousands of constituents.

Valuing Ecosystem Services with Fishery Rents: A Lumped-Parameter Approach to Hypoxia in the Neuse River Estuary

Directory of Open Access Journals (Sweden)

Larry B. Crowder

2011-11-01

Full Text Available Valuing ecosystem services with microeconomic underpinnings presents challenges because these services typically constitute nonmarket values and contribute to human welfare indirectly through a series of ecological pathways that are dynamic, nonlinear, and difficult to quantify and link to appropriate economic spatial and temporal scales. This paper develops and demonstrates a method to value a portion of ecosystem services when a commercial fishery is dependent on the quality of estuarine habitat. Using a lumped-parameter, dynamic open access bioeconomic model that is spatially explicit and includes predator-prey interactions, this paper quantifies part of the value of improved ecosystem function in the Neuse River Estuary when nutrient pollution is reduced. Specifically, it traces the effects of nitrogen loading on the North Carolina commercial blue crab fishery by modeling the response of primary production and the subsequent impact on hypoxia (low dissolved oxygen. Hypoxia, in turn, affects blue crabs and their preferred prey. The discounted present value fishery rent increase from a 30% reduction in nitrogen loadings in the Neuse is $2.56 million, though this welfare estimate is fairly sensitive to some parameter values. Surprisingly, this number is not sensitive to initial conditions.

Rogue waves and lump solutions for a (3+1)-dimensional generalized B-type Kadomtsev-Petviashvili equation in fluid mechanics

Science.gov (United States)

Wu, Xiao-Yu; Tian, Bo; Chai, Han-Peng; Sun, Yan

2017-08-01

Under investigation in this letter is a (3+1)-dimensional generalized B-type Kadomtsev-Petviashvili equation, which describes the weakly dispersive waves propagating in a fluid. Employing the Hirota method and symbolic computation, we obtain the lump, breather-wave and rogue-wave solutions under certain constraints. We graphically study the lump waves with the influence of the parameters h1, h3 and h5 which are all the real constants: When h1 increases, amplitude of the lump wave increases, and location of the peak moves; when h3 increases, lump wave’s amplitude decreases, but location of the peak keeps unchanged; when h5 changes, lump wave’s peak location moves, but amplitude keeps unchanged. Breather waves and rogue waves are displayed: Rogue waves emerge when the periods of the breather waves go to the infinity.

On the treatment of plane fusion front in lumped parameter thermal models with convection

International Nuclear Information System (INIS)

Le Tellier, R.; Skrzypek, E.; Saas, L.

2017-01-01

Highlights: • Solid phase approximations for a two-phase Stefan fusion problem with convection are analyzed. • A reference solution combines integral conservation eqs and a FE solution of the 1D heat equation. • Numerical results are presented for a transient in light water reactor severe accident analysis. • The models performances are highlighted on fusion transients in terms of Biot and Stefan numbers. - Abstract: Within the framework of lumped parameter models for integral codes, this paper focuses on the modeling of a two-phase Stefan fusion problem with natural convection in the liquid phase. In particular, this specific Stefan problem is of interest when studying corium pool behavior in the framework of light water reactor severe accident analysis. The objective of this research is to analyze the applicability of different approximations related to the modeling of the solid phase in terms of boundary heat flux closure relations. Three different approximations are considered: a quadratic profile based model, a model where a parameter controls the power partitioning at the interface and the steady state conduction assumption. These models are compared with an accurate front-tracking solution of this plane fusion front problem. This “reference” is obtained by combining the same integral conservation equations as the approximate models with a mesh-based solution of the 1D heat equation. Numerical results are discussed for a typical configuration of interest for corium pool analysis. Different fusion transients (constructed from nondimensionalization considerations in terms of Biot and Stefan numbers) are used in order to highlight the potential and limitations of the different approximations.

Definition of datum of materials lump size on conveyors by means of reflected gamma-radiation method

International Nuclear Information System (INIS)

Gal'yanov, A.V.; Antonov, V.A.; Laptev, Yu.V.

2001-01-01

A method of technological control of large-size lumps in conveyor-transported crushed material based on intensity measurement of X-ray and gamma radiation reflected from the material surface was suggested. The method was substantiated theoretically and as a result it was shown that dispersion of radiation intensity, multiply measured for short periods of time, can be analytic parameter of large-size lumps yield. Principled methodical and design recommendations on the method practical applications are given [ru

Layered storage of biogenic methane-enriched gas bubbles in peat: A lumped capacitance model controlled by soil structure

Science.gov (United States)

Chen, X.; Comas, X.; Binley, A. M.; Slater, L. D.

2017-12-01

Methane can accumulate in the gaseous phase in peats, and enter the atmosphere as gas bubbles with a mass flux higher than that via diffusion and plant-mediated pathways. A complete understanding of the mechanisms regulating bubble storage in peats remains incomplete. We developed a layered model to quantify the storage of gas bubbles over a peat column based on a general lumped capacitance model. This conceptual model was applied to explain the effects of peat structure on bubble storage at different depths observed in a laboratory experiment. A peat monolith was collected from the Everglades, a subtropical wetland located in Florida (USA), and kept submerged in a cuboid chamber over 102 days until gas bubble saturation was achieved. Time-lapse ground-penetrating radar (GPR) was used to estimate changes in gas content of each layer and the corresponding average dimensions of stored gas bubbles. The results highlight a hotspot layer of bubble accumulation at depths between 5 and 10 cm below the monolith surface. Bubbles in this shallow hotspot layer were larger relative to those in deeper layers, whilst the degree of decomposition of the upper layers was generally smaller than that of the lower layers based on von Post humification tests. X-ray Computer tomography (CT) was applied to resin-impregnated peat sections from different depths and the results showed that a higher porosity promotes bubbles storage. The stored gas bubbles were released by changing water levels and the air CH4 concentrations above the peat monolith were measured using a flow-through chamber system to confirm the high CH4 concentration in the stored bubbles. Our findings suggest that bubble capacitance is related to the difference in size between gas bubbles and peat pores. This work has implications for better understanding how changes in water table elevation associated with climate change and sea level rise (particularly for freshwater wetlands near coastal areas like the Everglades) may

Analysis of direct contact membrane distillation based on a lumped-parameter dynamic predictive model

KAUST Repository

Karam, Ayman M.; Alsaadi, Ahmad Salem; Ghaffour, NorEddine; Laleg-Kirati, Taous-Meriem

2016-01-01

Membrane distillation (MD) is an emerging technology that has a great potential for sustainable water desalination. In order to pave the way for successful commercialization of MD-based water desalination techniques, adequate and accurate dynamical models of the process are essential. This paper presents the predictive capabilities of a lumped-parameter dynamic model for direct contact membrane distillation (DCMD) and discusses the results under wide range of steady-state and dynamic conditions. Unlike previous studies, the proposed model captures the time response of the spacial temperature distribution along the flow direction. It also directly solves for the local temperatures at the membrane interfaces, which allows to accurately model and calculate local flux values along with other intrinsic variables of great influence on the process, like the temperature polarization coefficient (TPC). The proposed model is based on energy and mass conservation principles and analogy between thermal and electrical systems. Experimental data was collected to validated the steady-state and dynamic responses of the model. The obtained results shows great agreement with the experimental data. The paper discusses the results of several simulations under various conditions to optimize the DCMD process efficiency and analyze its response. This demonstrates some potential applications of the proposed model to carry out scale up and design studies. © 2016

Analysis of direct contact membrane distillation based on a lumped-parameter dynamic predictive model

KAUST Repository

Karam, Ayman M.

2016-10-03

Membrane distillation (MD) is an emerging technology that has a great potential for sustainable water desalination. In order to pave the way for successful commercialization of MD-based water desalination techniques, adequate and accurate dynamical models of the process are essential. This paper presents the predictive capabilities of a lumped-parameter dynamic model for direct contact membrane distillation (DCMD) and discusses the results under wide range of steady-state and dynamic conditions. Unlike previous studies, the proposed model captures the time response of the spacial temperature distribution along the flow direction. It also directly solves for the local temperatures at the membrane interfaces, which allows to accurately model and calculate local flux values along with other intrinsic variables of great influence on the process, like the temperature polarization coefficient (TPC). The proposed model is based on energy and mass conservation principles and analogy between thermal and electrical systems. Experimental data was collected to validated the steady-state and dynamic responses of the model. The obtained results shows great agreement with the experimental data. The paper discusses the results of several simulations under various conditions to optimize the DCMD process efficiency and analyze its response. This demonstrates some potential applications of the proposed model to carry out scale up and design studies. © 2016

A lumped parameter core dynamics model for MTR type research reactors under natural convection regime

International Nuclear Information System (INIS)

Ardaneh, Kazem; Zaferanlouei, Salman

2013-01-01

Highlights: ► A model is presented to simulate the reactivity insertion transient in MTR reactors. ► Transient dynamics of IAEA 10 MW MTR type research reactor are evaluated. ► Maximum unprotected reactivity insertion for safe condition is calculated. ► The model predictions are validated with corresponding results in the literature. - Abstract: On the basis of lumped parameter modeling of both the kinetic and thermal–hydraulic effects, a reasonably accurate simplified model has been developed to predict the dynamic response of MTR reactors following to an unprotected reactivity insertion under natural convection regime. By this model the reactor transient behavior at a given initial steady-state can be solved by a set of ordinary differential equations. The model predictions have an acceptable consent with corresponding results of reactivity insertion transients analyzed in the literature. The inherent safety characteristics of MTR research reactors utilizing natural convection is clearly demonstrated by the expanded model. The safety margin of reactor operating is selected ONB condition and thereby the proposed model determines that any slight increase in the value of $0.73 for inserted reactivity will cause the maximum cladding surface temperature to exceed the ONB condition

A 3D Dynamic Lumped Parameter Thermal Network of Air-Cooled YASA Axial Flux Permanent Magnet Synchronous Machine

Directory of Open Access Journals (Sweden)

Abdalla Hussein Mohamed

2018-03-01

Full Text Available To find the temperature rise for high power density yokeless and segmented armature (YASA axial flux permanent magnet synchronous (AFPMSM machines quickly and accurately, a 3D lumped parameter thermal model is developed and validated experimentally and by finite element (FE simulations on a 4 kW YASA machine. Additionally, to get insight in the thermal transient response of the machine, the model accounts for the thermal capacitance of different machine components. The model considers the stator, bearing, and windage losses, as well as eddy current losses in the magnets on the rotors. The new contribution of this work is that the thermal model takes cooling via air channels between the magnets on the rotor discs into account. The model is parametrized with respect to the permanent magnet (PM angle ratio, the PM thickness ratio, the air gap length, and the rotor speed. The effect of the channels is incorporated via convection equations based on many computational fluid dynamics (CFD computations. The model accuracy is validated at different values of parameters by FE simulations in both transient and steady state. The model takes less than 1 s to solve for the temperature distribution.

Lumped Parameter experiments for Single Mode Fiber Laser Cutting of Thin Stainless Steel Plate

Science.gov (United States)

Lai, Shengying; Jia, Ye; Han, Bing; Wang, Jun; Liu, Zongkai; Ni, Xiaowu; Shen, Zhonghua; Lu, Jian

2017-06-01

The present work reports the parameters on laser cutting stainless steel including workpiece thickness, cutting speed, defocus length and assisting gas pressure. The cutting kerf width, dross attachment and cut edge squareness deviation are examined to provide information on cutting quality. The results show that with the increasing thickness, the cutting speed decrease rate is about 27%. The optimal ranges of cutting speed, defocus length and gas pressure are obtained with maximum quality. The first section in your paper

Single lump breast surface stress assessment study

Science.gov (United States)

Vairavan, R.; Ong, N. R.; Sauli, Z.; Kirtsaeng, S.; Sakuntasathien, S.; Paitong, P.; Alcain, J. B.; Lai, S. L.; Retnasamy, V.

2017-09-01

Breast cancer is one of the commonest cancers diagnosed among women around the world. Simulation approach has been utilized to study, characterize and improvise detection methods for breast cancer. However, minimal simulation work has been done to evaluate the surface stress of the breast with lumps. Thus, in this work, simulation analysis was utilized to evaluate and assess the breast surface stress due to the presence of a lump within the internal structure of the breast. The simulation was conducted using the Elmer software. Simulation results have confirmed that the presence of a lump within the breast causes stress on the skin surface of the breast.

28 CFR 523.16 - Lump sum awards.

Science.gov (United States)

2010-07-01

... satisfactory performance of an unusually hazardous assignment; (c) An act which protects the lives of staff or... TRANSFER COMPUTATION OF SENTENCE Extra Good Time § 523.16 Lump sum awards. Any staff member may recommend... award is calculated. No seniority is accrued for such awards. Staff may recommend lump sum awards of...

The application of model with lumped parameters for transient condition analyses of NPP; Primena modela sa koncentrisanim parametrima za analize pelaznih stanja nukleane elektrane

Energy Technology Data Exchange (ETDEWEB)

Stankovic, B [Institut GOSA, Beograd (Yugoslavia); Stevanovic, V [Masinski fakultet, Beograd (Yugoslavia)

1985-07-01

The transient behaviour of NPP Krsko during the accident of pressurizer spray valve stuck open has been simulated y lumped parameters model of the PWR coolant system components, developed at the faculty of Mechanical Engineering, University of Belgrade. The elementary volumes which are characterised by the process and state parameters, and by junctions which are characterised by the geometrical and flow parameters are basic structure of physical model. The process parameters obtained by the model RESI, show qualitative agreement with the measured valves, in a degree in which the actions of reactor safety engineered system and emergency core cooling system are adequately modelled; in spite of the elementary physical model structure and only the modelling of thermal process in reactor core and equilibrium conditions of pressurizer and steam generator. The pressurizer pressure and liquid level predicted by the non-equilibrium pressurizer model SOP show good agreement until the HIPS (high pressure pumps) is activated. (author)

Statistical parameter characteristics of gas-phase fluctuations for gas-liquid intermittent flow

Energy Technology Data Exchange (ETDEWEB)

Matsui, G.; Monji, H.; Takaguchi, M. [Univ. of Tsukuba (Japan)

1995-09-01

This study deals with theoretical analysis on the general behaviour of statistical parameters of gas-phase fluctuations and comparison of statistical parameter characteristics for the real void fraction fluctuations measured with those for the wave form modified the real fluctuations. In order to investigate the details of the relation between the behavior of the statistical parameters in real intermittent flow and analytical results obtained from information on the real flow, the distributions of statistical parameters for general fundamental wave form of gas-phase fluctuations are discussed in detail. By modifying the real gas-phase fluctuations to a trapezoidaly wave, the experimental results can be directly compared with the analytical results. The analytical results for intermittent flow show that the wave form parameter, and the total amplitude of void fraction fluctuations, affects strongly on the statistical parameter characteristics. The comparison with experiment using nitrogen gas-water intermittent flow suggests that the parameters of skewness and excess may be better as indicators of flow pattern. That is, the macroscopic nature of intermittent flow can be grasped by the skewness and the excess, and the detailed flow structure may be described by the mean and the standard deviation.

Statistical parameter characteristics of gas-phase fluctuations for gas-liquid intermittent flow

International Nuclear Information System (INIS)

Matsui, G.; Monji, H.; Takaguchi, M.

1995-01-01

This study deals with theoretical analysis on the general behaviour of statistical parameters of gas-phase fluctuations and comparison of statistical parameter characteristics for the real void fraction fluctuations measured with those for the wave form modified the real fluctuations. In order to investigate the details of the relation between the behavior of the statistical parameters in real intermittent flow and analytical results obtained from information on the real flow, the distributions of statistical parameters for general fundamental wave form of gas-phase fluctuations are discussed in detail. By modifying the real gas-phase fluctuations to a trapezoidaly wave, the experimental results can be directly compared with the analytical results. The analytical results for intermittent flow show that the wave form parameter, and the total amplitude of void fraction fluctuations, affects strongly on the statistical parameter characteristics. The comparison with experiment using nitrogen gas-water intermittent flow suggests that the parameters of skewness and excess may be better as indicators of flow pattern. That is, the macroscopic nature of intermittent flow can be grasped by the skewness and the excess, and the detailed flow structure may be described by the mean and the standard deviation

Representing Lumped Markov Chains by Minimal Polynomials over Field GF(q)

Science.gov (United States)

Zakharov, V. M.; Shalagin, S. V.; Eminov, B. F.

2018-05-01

A method has been proposed to represent lumped Markov chains by minimal polynomials over a finite field. The accuracy of representing lumped stochastic matrices, the law of lumped Markov chains depends linearly on the minimum degree of polynomials over field GF(q). The method allows constructing the realizations of lumped Markov chains on linear shift registers with a pre-defined “linear complexity”.

Control oriented modeling of ejector in anode gas recirculation solid oxygen fuel cell systems

International Nuclear Information System (INIS)

Zhu Yinhai; Li Yanzhong; Cai Wenjian

2011-01-01

A one-equation model is proposed for fuel ejector in anode gas recirculation solid oxide fuel cell (SOFC) system. Firstly, the fundamental governing equations are established by employing the thermodynamic, fluid dynamic principles and chemical constraints inside the ejector; secondly, the one-equation model is derived by using the parameter analysis and lumped-parameter method. Finally, the computational fluid dynamics (CFD) technique is employed to obtain the source data for determining the model parameters. The effectiveness of the model is studied under a wide range of operation conditions. The effect of ejector performance on the anode gas recirculation SOFC system is also discussed. The presented model, which only contains four constant parameters, is useful in real-time control and optimization of fuel ejector in the anode gas recirculation SOFC system.

Real-time simulation of response to load variation for a ship reactor based on point-reactor double regions and lumped parameter model

Energy Technology Data Exchange (ETDEWEB)

Wang Qiao; Zhang De [Department of Nuclear Energy Science and Engineering, Naval University of Engineering, Wuhan 430033 (China); Chen Wenzhen, E-mail: Cwz2@21cn.com [Department of Nuclear Energy Science and Engineering, Naval University of Engineering, Wuhan 430033 (China); Chen Zhiyun [Department of Nuclear Energy Science and Engineering, Naval University of Engineering, Wuhan 430033 (China)

2011-05-15

Research highlights: > We calculate the variation of main parameters of the reactor core by the Simulink. > The Simulink calculation software (SCS) can deal well with the stiff problem. > The high calculation precision is reached with less time, and the results can be easily displayed. > The quick calculation of ship reactor transient can be achieved by this method. - Abstract: Based on the point-reactor double regions and lumped parameter model, while the nuclear power plant second loop load is increased or decreased quickly, the Simulink calculation software (SCS) is adopted to calculate the variation of main physical and thermal-hydraulic parameters of the reactor core. The calculation results are compared with those of three-dimensional simulation program. It is indicated that the SCS can deal well with the stiff problem of the point-reactor kinetics equations and the coupled problem of neutronics and thermal-hydraulics. The high calculation precision can be reached with less time, and the quick calculation of parameters of response to load disturbance for the ship reactor can be achieved. The clear image of the calculation results can also be displayed quickly by the SCS, which is very significant and important to guarantee the reactor safety operation.

Analysis and design of lumped element Marchand baluns

DEFF Research Database (Denmark)

Johansen, Tom Keinicke; Krozer, Viktor

2008-01-01

In this paper a novel design procedure for lumped element Marchand baluns is proposed. An analysis is performed on the balun structure in order to determine the conditions for ideal balun performance in terms of the lumped element values. The analysis is verified by two broadband designs centered...... around 22.75 GHz and differing only in terms of their impedance transformation ratio. EM simulation results on our proposed lumped element Marchand balun structure predicts an insertion loss of 4 dB and return loss of 40 dB at the design frequency of 22.75 GHz. The amplitude and phase imbalance...

Pembelajaran Seni Tari Kuda Lumping Di Desa Dukuhwaluh Kecamatan Kembaran Kab. Banyumas

OpenAIRE

Daryanto, Daryanto

2011-01-01

The goals this research were to determine: 1). What are the requirements given to prospective players of Kuda Lumping; 2). What material provided and what methods are used in training Kuda Lumping; 3). What is the cost required to conduct training of Kuda Lumping, and from which source. 4). How long does it take to produce players who are ready to perform Kuda Lumping showcased in front of an audience. From the research result shows that: 1. Requirements given to players of Kuda Lumping...

PEMBELAJARAN SENI TARI KUDA LUMPING DI DESA DUKUHWALUH KECAMATAN KEMBARAN KAB. BANYUMAS

OpenAIRE

Daryanto Daryanto

2011-01-01

The goals this research were to determine: 1). What are the requirements given to prospective players of Kuda Lumping; 2). What material provided and what methods are used in training Kuda Lumping; 3). What is the cost required to conduct training of Kuda Lumping, and from which source. 4). How long does it take to produce players who are ready to perform Kuda Lumping showcased in front of an audience. From the research result shows that: 1. Requirements given to players of Kuda Lumping...

Decay of Kadomtsev-Petviashvili lumps in dissipative media

Science.gov (United States)

Clarke, S.; Gorshkov, K.; Grimshaw, R.; Stepanyants, Y.

2018-03-01

The decay of Kadomtsev-Petviashvili lumps is considered for a few typical dissipations-Rayleigh dissipation, Reynolds dissipation, Landau damping, Chezy bottom friction, viscous dissipation in the laminar boundary layer, and radiative losses caused by large-scale dispersion. It is shown that the straight-line motion of lumps is unstable under the influence of dissipation. The lump trajectories are calculated for two most typical models of dissipation-the Rayleigh and Reynolds dissipations. A comparison of analytical results obtained within the framework of asymptotic theory with the direct numerical calculations of the Kadomtsev-Petviashvili equation is presented. Good agreement between the theoretical and numerical results is obtained.

Inhalation Exposure to PM-Bound Polycyclic Aromatic Hydrocarbons Released from Barbecue Grills Powered by Gas, Lump Charcoal, and Charcoal Briquettes.

Science.gov (United States)

Badyda, Artur J; Widziewicz, Kamila; Rogula-Kozłowska, Wioletta; Majewski, Grzegorz; Jureczko, Izabela

2018-01-01

The present study seeks to define the possible cancer risk arising from the inhalation exposure to particle (PM)-bound polycyclic aromatic hydrocarbons (PAHs) present in barbecue emission gases and to compare the risk depending on the type of fuel used for grill powering. Three types of fuel were compared: liquid propane gas, lump charcoal, and charcoal briquettes. PM 2.5 and PM 2.5-100 were collected during grilling. Subsequently, 16 PAHs congeners were extracted from the PM samples and measured quantitatively using gas chromatography. The content of PM-bound PAHs was used to calculate PAHs deposition in the respiratory tract using the multiple path particle dosimetry model. Finally, a probabilistic risk model was developed to assess the incremental lifetime cancer risk (ILCR) faced by people exposed to PAHs. We found a distinctly greater PAHs formation in case of grills powered by charcoal briquettes. The summary concentration of PAHs (Σ16PAH) ranged from inhale barbecue particles for 5 h a day, 40 days a year exceeds the acceptable level set by the U.S. Environmental Protection Agency. We conclude that the type of heat source used for grilling influences the PM-bound PAHs formation. The greatest concentration of PAHs is generated when grilling over charcoal briquettes. Loading grills with food generates conspicuously more PAHs emissions. Traditional grilling poses cancer risk much above the acceptable limit, as opposed to much less risk involving gas powered grills.

A Calibrated Lumped Element Model for the Prediction of PSJ Actuator Efficiency Performance

Directory of Open Access Journals (Sweden)

Matteo Chiatto

2018-03-01

Full Text Available Among the various active flow control techniques, Plasma Synthetic Jet (PSJ actuators, or Sparkjets, represent a very promising technology, especially because of their high velocities and short response times. A practical tool, employed for design and manufacturing purposes, consists of the definition of a low-order model, lumped element model (LEM, which is able to predict the dynamic response of the actuator in a relatively quick way and with reasonable fidelity and accuracy. After a brief description of an innovative lumped model, this work faces the experimental investigation of a home-designed and manufactured PSJ actuator, for different frequencies and energy discharges. Particular attention has been taken in the power supply system design. A specific home-made Pitot tube has allowed the detection of velocity profiles along the jet radial direction, for various energy discharges, as well as the tuning of the lumped model with experimental data, where the total device efficiency has been assumed as a fitting parameter. The best fitting value not only contains information on the actual device efficiency, but includes some modeling and experimental uncertainties, related also to the used measurement technique.

PEMBELAJARAN SENI TARI KUDA LUMPING DI DESA DUKUHWALUH KECAMATAN KEMBARAN KAB. BANYUMAS

Directory of Open Access Journals (Sweden)

Daryanto Daryanto

2011-03-01

Full Text Available The goals this research were to determine: 1. What are the requirements given to prospective players of Kuda Lumping; 2. What material provided and what methods are used in training Kuda Lumping; 3. What is the cost required to conduct training of Kuda Lumping, and from which source. 4. How long does it take to produce players who are ready to perform Kuda Lumping showcased in front of an audience. From the research result shows that: 1. Requirements given to players of Kuda Lumping (Ebeg, are namely: (1 has Kuda Lumping, (2 can dance in group / compact dance, (3 perform the ritual bathing and diving in rivers and (4 conduct ”Ngasrep” or fasting for 3 (three days without stopping. 2. The practice material was first given to prospective players Kuda Lumping is dance. In practing the dance material, the new dancers were directly guided by the seniors. The method used is by giving examples of dancing by the senior players to prospective players. When giving examples accompanied by gamelan / music, while dancer candidates of Kuda Lumping followed. 3. Fee required for training activities at least IDR 400,000,- (four hundred thousand rupiah. This cost does not include the cost to buy a kuda lumping. Sources of cost comes from the self-help group members of kuda lumping, like dalang ( director of the dance and local people. It means the training and activities of Kuda Lumping, did not receive funding / donations from the government, both the village and district governments. The cost for training activities was used to rent the gamelan, to purchase clothing / costume players, “sesaji”, consumption and honorariums. 4. To train / produce, it take a player at least 3.5 (three and a half months and a maximum of 7 (seven months. This calculation is based on the starting time of dance exercise, until doing the bath in the river as the last stage. Key Wordsi: Kuda lumping, learning ,ngasrep, ritual of bathe, ritual offerings, wayang,

Analysis of groundwater discharge with a lumped-parameter model, using a case study from Tajikistan

Science.gov (United States)

Pozdniakov, S. P.; Shestakov, V. M.

A lumped-parameter model of groundwater balance is proposed that permits an estimate of discharge variability in comparison with the variability of recharge, by taking into account the influence of aquifer parameters. Recharge-discharge relationships are analysed with the model for cases of deterministic and stochastic recharge time-series variations. The model is applied to study the temporal variability of groundwater discharge in a river valley in the territory of Tajikistan, an independent republic in Central Asia. Résumé Un modèle global de bilan d'eau souterraine a été développé pour estimer la variabilité de l'écoulement par rapport à celle de la recharge, en prenant en compte l'influence des paramètres de l'aquifère. Les relations entre recharge et écoulement sont analysées à l'aide du modèle pour des variations des chroniques de recharge soit déterministes, soit stochastiques. Le modèle est appliquéà l'étude de la variabilité temporelle de l'écoulement souterrain vers une rivière, dans le Tadjikistan, une république indépendante d'Asie centrale. Resumen Se propone un modelo de parámetros concentrados para realizar el balance de aguas subterráneas, el cual permite estimar la variabilidad en la descarga con respecto a la variabilidad en la recarga, en función de los parámetros que caracterizan el acuífero. Las relaciones entre recarga y descarga se analizan con el modelo para distintos casos de series temporales de recarga, tanto deterministas como estocásticas. El modelo se aplica al estudio de la variabilidad temporal de la descarga en un valle aluvial de Tadyikistán, una república independiente del Asia Central.

Comments on lump solutions in SFT

International Nuclear Information System (INIS)

Bonora, Loriano; Tolla, Driba D.

2016-01-01

We analyze a recently proposed scheme to construct analytic lump solutions in open SFT. We argue that in order for the scheme to be operative and to guarantee background independence it must be implemented in the same 2D conformal field theory in which SFT is formulated. We outline and discuss two different possible approaches. Next we reconsider an older proposal for analytic lump solutions and implement a few improvements. In the course of the analysis we formulate a distinction between regular and singular gauge transformations and advocate the necessity of defining a topology in the space of string fields. (orig.)

Comments on lump solutions in SFT

Energy Technology Data Exchange (ETDEWEB)

Bonora, Loriano; Tolla, Driba D. [International School for Advanced Studies (SISSA), Trieste (Italy); INFN, Sezione di Trieste, Trieste (Italy)

2016-04-15

We analyze a recently proposed scheme to construct analytic lump solutions in open SFT. We argue that in order for the scheme to be operative and to guarantee background independence it must be implemented in the same 2D conformal field theory in which SFT is formulated. We outline and discuss two different possible approaches. Next we reconsider an older proposal for analytic lump solutions and implement a few improvements. In the course of the analysis we formulate a distinction between regular and singular gauge transformations and advocate the necessity of defining a topology in the space of string fields. (orig.)

Application of Mass Lumped Higher Order Finite Elements

International Nuclear Information System (INIS)

J. Chen, H.R. Strauss, S.C. Jardin, W. Park, L.E. Sugiyama, G. Fu, J. Breslau

2005-01-01

There are many interesting phenomena in extended-MHD such as anisotropic transport, mhd, 2-fluid effects stellarator and hot particles. Any one of them challenges numerical analysts, and researchers are seeking for higher order methods, such as higher order finite difference, higher order finite elements and hp/spectral elements. It is true that these methods give more accurate solution than their linear counterparts. However, numerically they are prohibitively expensive. Here we give a successful solution of this conflict by applying mass lumped higher order finite elements. This type of elements not only keep second/third order accuracy but also scale closely to linear elements by doing mass lumping. This is especially true for second order lump elements. Full M3D and anisotropic transport models are studied

lumpR 2.0.0: an R package facilitating landscape discretisation for hillslope-based hydrological models

Science.gov (United States)

Pilz, Tobias; Francke, Till; Bronstert, Axel

2017-08-01

The characteristics of a landscape pose essential factors for hydrological processes. Therefore, an adequate representation of the landscape of a catchment in hydrological models is vital. However, many of such models exist differing, amongst others, in spatial concept and discretisation. The latter constitutes an essential pre-processing step, for which many different algorithms along with numerous software implementations exist. In that context, existing solutions are often model specific, commercial, or depend on commercial back-end software, and allow only a limited or no workflow automation at all. Consequently, a new package for the scientific software and scripting environment R, called lumpR, was developed. lumpR employs an algorithm for hillslope-based landscape discretisation directed to large-scale application via a hierarchical multi-scale approach. The package addresses existing limitations as it is free and open source, easily extendible to other hydrological models, and the workflow can be fully automated. Moreover, it is user-friendly as the direct coupling to a GIS allows for immediate visual inspection and manual adjustment. Sufficient control is furthermore retained via parameter specification and the option to include expert knowledge. Conversely, completely automatic operation also allows for extensive analysis of aspects related to landscape discretisation. In a case study, the application of the package is presented. A sensitivity analysis of the most important discretisation parameters demonstrates its efficient workflow automation. Considering multiple streamflow metrics, the employed model proved reasonably robust to the discretisation parameters. However, parameters determining the sizes of subbasins and hillslopes proved to be more important than the others, including the number of representative hillslopes, the number of attributes employed for the lumping algorithm, and the number of sub-discretisations of the representative hillslopes.

A Temperature Dependent Lumped-charge Model for Trench FS-IGBT

DEFF Research Database (Denmark)

Duan, Yaoqiang; Kang, Yong; Iannuzzo, Francesco

2018-01-01

Abstract: This paper proposes a temperature dependent lumped-charge model for FS-IGBT. Due to the evolution of the IGBT structure, the existing lumped-charge IGBT model established for NPT-IGBT is not suitable for the simulation of FS-IGBT. This paper extends the lumped-charge IGBT model including...... the field-stop (FS) structure and temperature characteristics. The temperature characteristics of the model are considered for both the bipolar part and unipolar part. In addition, a new PN junction model which can distinguish the collector structure is presented and validated by TCAD simulation. Finally...

Experimental realization of optical lumped nanocircuits at infrared wavelengths.

Science.gov (United States)

Sun, Yong; Edwards, Brian; Alù, Andrea; Engheta, Nader

2012-01-29

The integration of radiofrequency electronic methodologies on micro- as well as nanoscale platforms is crucial for information processing and data-storage technologies. In electronics, radiofrequency signals are controlled and manipulated by 'lumped' circuit elements, such as resistors, inductors and capacitors. In earlier work, we theoretically proposed that optical nanostructures, when properly designed and judiciously arranged, could behave as nanoscale lumped circuit elements--but at optical frequencies. Here, for the first time we experimentally demonstrate a two-dimensional optical nanocircuit at mid-infrared wavelengths. With the guidance of circuit theory, we design and fabricate arrays of Si3N4 nanorods with specific deep subwavelength cross-sections, quantitatively evaluate their equivalent impedance as lumped circuit elements in the mid-infrared regime, and by Fourier transform infrared spectroscopy show that these nanostructures can indeed function as two-dimensional optical lumped circuit elements. We further show that the connections among nanocircuit elements, in particular whether they are in series or in parallel combination, can be controlled by the polarization of impinging optical signals, realizing the notion of 'stereo-circuitry' in metatronics-metamaterials-inspired optical circuitry.

The role of men in early detection of their spouses' breast lump(s ...

African Journals Online (AJOL)

We aim to determine whether men can be of help in the early detection of lumps in their spouses' breast. 230 questionnaires were administered to married men. The responses were accepted as “yes” or “no. 217 men (94.35%) responded. 195 (89.86%) were aware of breast cancer. 212 ( 97.7%) were either Christians or ...

Rutting resistance of asphalt mixture with cup lumps modified binder

Science.gov (United States)

Shaffie, E.; Hanif, W. M. M. Wan; Arshad, A. K.; Hashim, W.

2017-11-01

Rutting is the most common pavement distress in pavement structures which occurs mainly due to several factors such as increasing of traffic volume, climatic conditions and also due to construction design errors. This failure reduced the service life of the pavement, reduced driver safety and increase cost of maintenance. Polymer Modified Binder has been observed for a long time in improving asphalt pavement performance. Research shows that the use of polymer in bituminous mix not only improve the resistance to rutting but also increase the life span of the pavement. This research evaluates the physical properties and rutting performance of dense graded Superpave-designed HMA mix. Two different types of dense graded Superpave HMA mix were developed consists of unmodified binder mix (UMB) and cup lumps rubber (liquid form) modified binder mix (CLMB). Natural rubber polymer modified binder was prepared from addition of 8 percent of cup lumps into binder. Results showed that all the mixes passed the Superpave volumetric properties criteria which indicate that these mixtures were good with respect to durability and flexibility. Furthermore, rutting results from APA rutting test was determined to evaluate the performance of these mixtures. The rutting result of CLMB demonstrates better resistance to rutting than those prepared using UMB mix. Addition of cup lumps rubber in asphalt mixture was found to be significant, where the cup lumps rubber has certainly improves the binder properties and enhanced its rutting resistance due to greater elasticity offered by the cup lumps rubber particles. It shows that the use of cup lumps rubber can significantly reduce the rut depth of asphalt mixture by 41% compared to the minimum rut depth obtained for the UMB mix. Therefore, it can be concluded that the cup lumps rubber is suitable to be used as a modifier to modified binder in order to enhance the properties of the binder and thus improves the performance of asphalt mixes.

A lumped model for rotational modes in periodic solid composites

KAUST Repository

Peng, Pai; Asiri, Sharefa M.; Zhang, Xiujuan; Li, Yan; Wu, Ying

2013-01-01

We present a lumped model to study the rotational modes in a type of two-dimensional periodic solid composites comprised of a square array of rubber-coated steel cylinders embedded in an epoxy matrix. The model captures the physical essence of rotational modes in such systems for various combinations of material parameters, and, therefore it is able to describe the transition behaviour when the system is gradually adjusted from an elastic metamaterial to an elastic phononic crystal. From the model, we can define a transition zone which separates the typical elastic metamaterials and the phononic crystals.

A lumped model for rotational modes in periodic solid composites

KAUST Repository

Peng, Pai

2013-10-01

We present a lumped model to study the rotational modes in a type of two-dimensional periodic solid composites comprised of a square array of rubber-coated steel cylinders embedded in an epoxy matrix. The model captures the physical essence of rotational modes in such systems for various combinations of material parameters, and, therefore it is able to describe the transition behaviour when the system is gradually adjusted from an elastic metamaterial to an elastic phononic crystal. From the model, we can define a transition zone which separates the typical elastic metamaterials and the phononic crystals.

Application of Factorial Design for Gas Parameter Optimization in CO2 Laser Welding

DEFF Research Database (Denmark)

Gong, Hui; Dragsted, Birgitte; Olsen, Flemming Ove

1997-01-01

The effect of different gas process parameters involved in CO2 laser welding has been studied by applying two-set of three-level complete factorial designs. In this work 5 gas parameters, gas type, gas flow rate, gas blowing angle, gas nozzle diameter, gas blowing point-offset, are optimized...... to be a very useful tool for parameter optimi-zation in laser welding process. Keywords: CO2 laser welding, gas parameters, factorial design, Analysis of Variance........ The bead-on-plate welding specimens are evaluated by a number of quality char-acteristics, such as the penetration depth and the seam width. The significance of the gas pa-rameters and their interactions are based on the data found by the Analysis of Variance-ANOVA. This statistic methodology is proven...

Use of Ventricular Assist Device in Univentricular Physiology: The Role of Lumped Parameter Models.

Science.gov (United States)

Di Molfetta, Arianna; Ferrari, Gianfranco; Filippelli, Sergio; Fresiello, Libera; Iacobelli, Roberta; Gagliardi, Maria G; Amodeo, Antonio

2016-05-01

Failing single-ventricle (SV) patients might benefit from ventricular assist devices (VADs) as a bridge to heart transplantation. Considering the complex physiopathology of SV patients and the lack of established experience, the aim of this work was to realize and test a lumped parameter model of the cardiovascular system, able to simulate SV hemodynamics and VAD implantation effects. Data of 30 SV patients (10 Norwood, 10 Glenn, and 10 Fontan) were retrospectively collected and used to simulate patients' baseline. Then, the effects of VAD implantation were simulated. Additionally, both the effects of ventricular assistance and cavopulmonary assistance were simulated in different pathologic conditions on Fontan patients, including systolic dysfunction, diastolic dysfunction, and pulmonary vascular resistance increment. The model can reproduce patients' baseline well. Simulation results suggest that the implantation of VAD: (i) increases the cardiac output (CO) in all the three palliation conditions (Norwood 77.2%, Glenn 38.6%, and Fontan 17.2%); (ii) decreases the SV external work (SVEW) (Norwood 55%, Glenn 35.6%, and Fontan 41%); (iii) increases the mean pulmonary arterial pressure (Pap) (Norwood 39.7%, Glenn 12.1%, and Fontan 3%). In Fontan circulation, with systolic dysfunction, the left VAD (LVAD) increases CO (35%), while the right VAD (RVAD) determines a decrement of inferior vena cava pressure (Pvci) (39%) with 34% increment of CO. With diastolic dysfunction, the LVAD increases CO (42%) and the RVAD decreases the Pvci. With pulmonary vascular resistance increment, the RVAD allows the highest CO (50%) increment with the highest decrement of Pvci (53%). The single ventricular external work (SVEW) increases (decreases) increasing the VAD speed in cavopulmonary (ventricular) assistance. Numeric models could be helpful in this challenging and innovative field to support patients and VAD selection to optimize the clinical outcome and personalize the therapy

Lumped versus distributed thermoregulatory control: results from a three-dimensional dynamic model.

Science.gov (United States)

Werner, J; Buse, M; Foegen, A

1989-01-01

In this study we use a three-dimensional model of the human thermal system, the spatial grid of which is 0.5 ... 1.0 cm. The model is based on well-known physical heat-transfer equations, and all parameters of the passive system have definite physical values. According to the number of substantially different areas and organs, 54 spatially different values are attributed to each physical parameter. Compatibility of simulation and experiment was achieved solely on the basis of physical considerations and physiological basic data. The equations were solved using a modification of the alternating direction implicit method. On the basis of this complex description of the passive system close to reality, various lumped and distributed parameter control equations were tested for control of metabolic heat production, blood flow and sweat production. The simplest control equations delivering results on closed-loop control compatible with experimental evidence were determined. It was concluded that it is essential to take into account the spatial distribution of heat production, blood flow and sweat production, and that at least for control of shivering, distributed controller gains different from the pattern of distribution of muscle tissue are required. For sweat production this is not so obvious, so that for simulation of sweating control after homogeneous heat load a lumped parameter control may be justified. Based on these conclusions three-dimensional temperature profiles for cold and heat load and the dynamics for changes of the environmental conditions were computed. In view of the exact simulation of the passive system and the compatibility with experimentally attainable variables there is good evidence that those values extrapolated by the simulation are adequately determined. The model may be used both for further analysis of the real thermoregulatory mechanisms and for special applications in environmental and clinical health care.

Estimation of time to rupture in a fire using 6FIRE, a lumped parameter UF6 cylinder transient heat transfer/stress analysis model

International Nuclear Information System (INIS)

Williams, W.R.; Anderson, J.C.

1995-01-01

The transportation of UF 6 is subject to regulations requiring the evaluation of packaging under a sequence of hypothetical accident conditions including exposure to a 30-min 800 degree C (1475 degree F) fire [10 CFR 71.73(c)(3)]. An issue of continuing interest is whether bare cylinders can withstand such a fire without rupturing. To address this issue, a lumped parameter heat transfer/stress analysis model (6FIRE) has been developed to simulate heating to the point of rupture of a cylinder containing UF 6 when it is exposed to a fire. The model is described, then estimates of time to rupture are presented for various cylinder types, fire temperatures, and fill conditions. An assessment of the quantity of UF 6 released from containment after rupture is also presented. Further documentation of the model is referenced

Lumped transmission line avalanche pulser

Science.gov (United States)

Booth, Rex

1995-01-01

A lumped linear avalanche transistor pulse generator utilizes stacked transistors in parallel within a stage and couples a plurality of said stages, in series with increasing zener diode limited voltages per stage and decreasing balanced capacitance load per stage to yield a high voltage, high and constant current, very short pulse.

20 CFR 222.44 - Other relationship determinations for lump-sum payments.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Other relationship determinations for lump... THE RAILROAD RETIREMENT ACT FAMILY RELATIONSHIPS Relationship as Parent, Grandchild, Brother or Sister... have the relationships to the employee shown below for lump-sum payment purposes: (a) Grandchildren. A...

Effect of nonlinear void reactivity on bifurcation characteristics of a lumped-parameter model of a BWR: A study relevant to RBMK

Energy Technology Data Exchange (ETDEWEB)

Verma, Dinkar, E-mail: dinkar@iitk.ac.in [Nuclear Engineering and Technology Program, Indian Institute of Technology Kanpur, Kanpur 208 016 (India); Kalra, Manjeet Singh, E-mail: drmanjeet.singh@dituniversity.edu.in [DIT University, Dehradun 248 009 (India); Wahi, Pankaj, E-mail: wahi@iitk.ac.in [Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

2017-04-15

Highlights: • A simplified model with nonlinear void reactivity feedback is studied. • Method of multiple scales for nonlinear analysis and oscillation characteristics. • Second order void reactivity dominates in determining system dynamics. • Opposing signs of linear and quadratic void reactivity enhances global safety. - Abstract: In the present work, the effect of nonlinear void reactivity on the dynamics of a simplified lumped-parameter model for a boiling water reactor (BWR) is investigated. A mathematical model of five differential equations comprising of neutronics and thermal-hydraulics encompassing the nonlinearities associated with both the reactivity feedbacks and the heat transfer process has been used. To this end, we have considered parameters relevant to RBMK for which the void reactivity is known to be nonlinear. A nonlinear analysis of the model exploiting the method of multiple time scales (MMTS) predicts the occurrence of the two types of Hopf bifurcation, namely subcritical and supercritical, leading to the evolution of limit cycles for a range of parameters. Numerical simulations have been performed to verify the analytical results obtained by MMTS. The study shows that the nonlinear reactivity has a significant influence on the system dynamics. A parametric study with varying nominal reactor power and operating conditions in coolant channel has also been performed which shows the effect of change in concerned parameter on the boundary between regions of sub- and super-critical Hopf bifurcations in the space constituted by the two coefficients of reactivities viz. the void and the Doppler coefficient of reactivities. In particular, we find that introduction of a negative quadratic term in the void reactivity feedback significantly increases the supercritical region and dominates in determining the system dynamics.

Real-Gas Correction Factors for Hypersonic Flow Parameters in Helium

Science.gov (United States)

Erickson, Wayne D.

1960-01-01

The real-gas hypersonic flow parameters for helium have been calculated for stagnation temperatures from 0 F to 600 F and stagnation pressures up to 6,000 pounds per square inch absolute. The results of these calculations are presented in the form of simple correction factors which must be applied to the tabulated ideal-gas parameters. It has been shown that the deviations from the ideal-gas law which exist at high pressures may cause a corresponding significant error in the hypersonic flow parameters when calculated as an ideal gas. For example the ratio of the free-stream static to stagnation pressure as calculated from the thermodynamic properties of helium for a stagnation temperature of 80 F and pressure of 4,000 pounds per square inch absolute was found to be approximately 13 percent greater than that determined from the ideal-gas tabulation with a specific heat ratio of 5/3.

Incidence of malignancy in females presenting with breast lumps in OPD: a study of 277 cases

International Nuclear Information System (INIS)

Chaudhary, I.A.; Qureshi, S.K.; Rasul, S.

2003-01-01

Objective: To find the incidence of malignancy in females presenting with breast lumps in surgical out patient and to find out the age related incidence of benign and malignant diseases in these patients. Patients and Methods: All cases reporting to surgical outdoor with breast lumps were included and underwent investigation for the breast lumps to determine the histopathological diagnosis. Results: A total of 277 cases were studied. 24.2% breast lumps were malignant and 75.8% were benign. The incidence of malignancy increases from 0% in 2nd decade to 38.9% in 5th and 100% in 9th decade of life. The probability of diagnosing a breast lump as a malignant is one in three in 4th decade, two in five in 5th decade and more than one in two there after. Fibrocystic disease (33.8%) and Fibro adenoma (27.1%) was the commonest finding among the benign lumps. Among malignant lumps infiltrating duct carcinoma (68.7%) is the commonest finding. Conclusion: There is a significantly high incidence of malignant breast lumps after the 3rd decade of life and it increases subsequently. It is recommended that the surgeon managing a case of breast lump in a patient above 30 years should be highly suspicious and cautious so that early detection and management of malignant lumps be carried out. (author)

Preparation of lumped fission product (FP) cross sections for a multigroup library

International Nuclear Information System (INIS)

Ono, S.; Corcuera, R.P.

1984-01-01

A method for the calculation of lumped Fission Product (FP) cross sections has been developed. The group constants fo each nuclide are generated by NJOY code, based on ENDF/B-V data. In this first version, cross section of 28 nuclides are lumped for typical characteristics of Binary Breeder Reactor (BBR). One energy group calculations are made for a 1000 MWe fast reactor to verify the influence of burnup, number of FP and fuel composition on the lumped fission product cross sections. (Author) [pt

Reduction in thermal conductivity of BiSbTe lump

Energy Technology Data Exchange (ETDEWEB)

Ahmad, Kaleem [King Saud University, Sustainable Energy Technologies Center, College of Engineering, PO Box 800, Riyadh (Saudi Arabia); Wan, C. [Tsinghua University, State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Beijing (China); Al-Eshaikh, M.A.; Kadachi, A.N. [King Saud University, Research Center, College of Engineering, PO Box 800, Riyadh (Saudi Arabia)

2017-03-15

In this work, systematic investigations on the thermal conductivities of BiSbTe lump, microstructured pristine BiSbTe bulk and single wall carbon nanotubes (SWCNTs)/BiSbTe bulk nanocomposites were performed. BiSbTe lumps were crushed to form a coarse powder (200 μm) and effect of particle size reduction on the effective thermal conductivity of BiSbTe (200 μm) bulk were analyzed. For further reduction in the conductivity, a two pronged strategy has been employed. First, additional refinement of BiSbTe (200 μm) were performed through ball milling in an inert environment. Second, SWCNTs in 0.75, and 1.0 vol% were distributed uniformly in the fine BiSbTe ball milled powder. The results showed that the effective thermal conductivities decrease with the reduction in the particle size from lump to BiSbTe (200 μm) bulk as well as with the addition of SWCNTs accompanied by further refinement of BiSbTe particles. The significant reduction in thermal conductivities of the lump was achieved for pure BiSbTe (200 μm) bulk and 0.75 vol% of SWCNTs/BiSbTe composite. This can be ascribed to the enhanced phonon scattering by the grain boundaries between the nanostructured BiSbTe particles as well as the interfaces between BiSbTe and the low dimensional carbon nanotubes. (orig.)

Comparing sensitivity analysis methods to advance lumped watershed model identification and evaluation

Directory of Open Access Journals (Sweden)

Y. Tang

2007-01-01

Full Text Available This study seeks to identify sensitivity tools that will advance our understanding of lumped hydrologic models for the purposes of model improvement, calibration efficiency and improved measurement schemes. Four sensitivity analysis methods were tested: (1 local analysis using parameter estimation software (PEST, (2 regional sensitivity analysis (RSA, (3 analysis of variance (ANOVA, and (4 Sobol's method. The methods' relative efficiencies and effectiveness have been analyzed and compared. These four sensitivity methods were applied to the lumped Sacramento soil moisture accounting model (SAC-SMA coupled with SNOW-17. Results from this study characterize model sensitivities for two medium sized watersheds within the Juniata River Basin in Pennsylvania, USA. Comparative results for the 4 sensitivity methods are presented for a 3-year time series with 1 h, 6 h, and 24 h time intervals. The results of this study show that model parameter sensitivities are heavily impacted by the choice of analysis method as well as the model time interval. Differences between the two adjacent watersheds also suggest strong influences of local physical characteristics on the sensitivity methods' results. This study also contributes a comprehensive assessment of the repeatability, robustness, efficiency, and ease-of-implementation of the four sensitivity methods. Overall ANOVA and Sobol's method were shown to be superior to RSA and PEST. Relative to one another, ANOVA has reduced computational requirements and Sobol's method yielded more robust sensitivity rankings.

29 CFR Appendix A to Part 4022 - Lump Sum Mortality Rates

Science.gov (United States)

2010-07-01

... 29 Labor 9 2010-07-01 2010-07-01 false Lump Sum Mortality Rates A Appendix A to Part 4022 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION COVERAGE AND BENEFITS BENEFITS PAYABLE IN TERMINATED SINGLE-EMPLOYER PLANS Pt. 4022, App. A Appendix A to Part 4022—Lump Sum Mortality...

Simulation of nonlinear dynamics of a PWR core by an improved lumped formulation for fuel heat transfer

International Nuclear Information System (INIS)

Su, Jian; Cotta, Renato M.

2000-01-01

In this work, thermohydraulic behaviour of PWR, during reactivity insertion and partial loss-of-flow, is simulated by using a simplified mathematical model of reactor core and primary coolant. An improved lumped parameter formulation for transient heat conduction in fuel rod is used for core heat transfer modelling. Transient temperature response of fuel, cladding and coolant is analysed. (author)

Fundamentals of electromagnetics 1 internal behavior of lumped elements

CERN Document Server

Voltmer, David

2007-01-01

This book is the first of two volumes which have been created to provide an understanding of the basic principles and applications of electromagnetic fields for electrical engineering students. Fundamentals of Electromagnetics Vol 1: Internal Behavior of Lumped Elements focuses upon the DC and low-frequency behavior of electromagnetic fields within lumped elements. The properties of electromagnetic fields provide the basis for predicting the terminal characteristics of resistors, capacitors, and inductors. The properties of magnetic circuits are included as well. For slightly higher frequencie

The nonextensive parameter for nonequilibrium electron gas in an electromagnetic field

International Nuclear Information System (INIS)

Yu, Haining; Du, Jiulin

2014-01-01

The nonextensive parameter for nonequilibrium electron gas of the plasma in an electromagnetic field is studied. We exactly obtained an expression of the q-parameter based on Boltzmann kinetic theories for plasmas, where Coulombian interactions and Lorentz forces play dominant roles. We show that the q-parameter different from unity is related by an equation to temperature gradient, electric field strength, magnetic induction as well as overall bulk velocity of the gas. The effect of the magnetic field on the q-parameter depends on the overall bulk velocity. Thus the q-parameter for the electron gas in an electromagnetic field represents the nonequilibrium nature or nonisothermal configurations of the plasma with electromagnetic interactions. - Highlights: • An expression of the q-parameter is obtained for nonequilibrium plasma with electromagnetic interactions. • The q-parameter is related to temperature gradient, electric field strength, magnetic induction as well as overall bulk velocity of the plasma. • The q-parameter represents the nonequilibrium nature of the complex plasma with electromagnetic interactions

The nonextensive parameter for nonequilibrium electron gas in an electromagnetic field

Energy Technology Data Exchange (ETDEWEB)

Yu, Haining; Du, Jiulin, E-mail: jldu@tju.edu.cn

2014-11-15

The nonextensive parameter for nonequilibrium electron gas of the plasma in an electromagnetic field is studied. We exactly obtained an expression of the q-parameter based on Boltzmann kinetic theories for plasmas, where Coulombian interactions and Lorentz forces play dominant roles. We show that the q-parameter different from unity is related by an equation to temperature gradient, electric field strength, magnetic induction as well as overall bulk velocity of the gas. The effect of the magnetic field on the q-parameter depends on the overall bulk velocity. Thus the q-parameter for the electron gas in an electromagnetic field represents the nonequilibrium nature or nonisothermal configurations of the plasma with electromagnetic interactions. - Highlights: • An expression of the q-parameter is obtained for nonequilibrium plasma with electromagnetic interactions. • The q-parameter is related to temperature gradient, electric field strength, magnetic induction as well as overall bulk velocity of the plasma. • The q-parameter represents the nonequilibrium nature of the complex plasma with electromagnetic interactions.

A correction technique for the dispersive effects of mass lumping for transport problems

KAUST Repository

Guermond, Jean-Luc

2013-01-01

This paper addresses the well-known dispersion effect that mass lumping induces when solving transport-like equations. A simple anti-dispersion technique based on the lumped mass matrix is proposed. The method does not require any non-trivial matrix inversion and has the same anti-dispersive effects as the consistent mass matrix. A novel quasi-lumping technique for P2 finite elements is introduced. Higher-order extensions of the method are also discussed. © 2012 Elsevier B.V.

A Hybrid Lumped Parameters/Finite Element/Boundary Element Model to Predict the Vibroacoustic Characteristics of an Axial Piston Pump

Directory of Open Access Journals (Sweden)

Shaogan Ye

2017-01-01

Full Text Available Low noise axial piston pumps become the rapid increasing demand in modern hydraulic fluid power systems. This paper proposes a systematic approach to simulate the vibroacoustic characteristics of an axial piston pump using a hybrid lumped parameters/finite element/boundary element (LP/FE/BE model, and large amount of experimental work was performed to validate the model. The LP model was developed to calculate the excitation forces and was validated by a comparison of outlet flow ripples. The FE model was developed to calculate the vibration of the pump, in which the modeling of main friction pairs using different spring elements was presented in detail, and the FE model was validated using experimental modal analysis and measured vibrations. The BE model was used to calculate the noise emitted from the pump, and a measurement of sound pressure level at representative field points in a hemianechoic chamber was conducted to validate the BE model. Comparisons between the simulated and measured results show that the developed LP/FE/BE model is effective in capturing the vibroacoustic characteristics of the pump. The presented approach can be extended to other types of fluid power components and contributes to the development of quieter fluid power systems.

Lumped hydrological models is an Occam' razor for runoff modeling in large Russian Arctic basins

OpenAIRE

Ayzel Georgy

2018-01-01

This study is aimed to investigate the possibility of three lumped hydrological models to predict daily runoff of large-scale Arctic basins for the modern period (1979-2014) in the case of substantial data scarcity. All models were driven only by meteorological forcing reanalysis dataset without any additional information about landscape, soil or vegetation cover properties of studied basins. We found limitations of model parameters calibration in ungauged basins using global optimization alg...

A correction technique for the dispersive effects of mass lumping for transport problems

KAUST Repository

Guermond, Jean-Luc; Pasquetti, Richard

2013-01-01

This paper addresses the well-known dispersion effect that mass lumping induces when solving transport-like equations. A simple anti-dispersion technique based on the lumped mass matrix is proposed. The method does not require any non-trivial matrix

Cross sections of the lumped fission products for the AMZ library

International Nuclear Information System (INIS)

Ono, S.; Corcueca, R.P.; Nascimento, J.A.

1985-01-01

The preparation of the lumped fission product cross section for the AMZ library is described. For this purpose 100 nuclides were selected. The cross sections for each nuclide were generated by the NJOY code with evaluated nuclear data from ENDF/B-V, complemented with ENDF/B-IV data. A comparison is performed between the data obtained and the lumped fission product cross section of JFS-II [pt

Optimization of basic parameters of cyclic operation of underground gas storages

Directory of Open Access Journals (Sweden)

Віктор Олександрович Заєць

2015-04-01

Full Text Available The problem of optimization of process parameters of cyclic operation of underground gas storages in gas mode is determined in the article. The target function is defined, expressing necessary capacity of compressor station for gas injection in the storage. Its minimization will find the necessary technological parameters, such as flow and reservoir pressure change over time. Limitations and target function are reduced to a linear form. Solution of problems is made by the simplex method

Study of Pellets and Lumps as Raw Materials in Silicon Production from Quartz and Silicon Carbide

Science.gov (United States)

Dal Martello, E.; Tranell, G.; Gaal, S.; Raaness, O. S.; Tang, K.; Arnberg, L.

2011-10-01

The use of high-purity carbon and quartz raw materials reduces the need for comprehensive refining steps after the silicon has been produced carbothermically in the electric reduction furnace. The current work aims at comparing the reaction mechanisms and kinetics occurring in the inner part of the reduction furnace when pellets or lumpy charge is used, as well as the effect of the raw material mix. Laboratory-scale carbothermic reduction experiments have been carried out in an induction furnace. High-purity silicon carbide and two different high-purity hydrothermal quartzes were charged as raw materials at different molar ratios. The charge was in the form of lumps (size, 2-5 mm) or as powder (size, 10-20 μm), mixed and agglomerated as pellets (size, 1-3 mm) and reacted at 2273 K (2000 °C). The thermal properties of the quartzes were measured also by heating a small piece of quartz in CO atmosphere. The investigated quartzes have different reactivity in reducing atmosphere. The carbothermal reduction experiments show differences in the reacted charge between pellets and lumps as charge material. Solid-gas reactions take place from the inside of the pellets porosity, whereas reactions in lumps occur topochemically. Silicon in pellets is produced mainly in the rim zone. Larger volumes of silicon have been found when using lumpy charge. More SiO is produced when using pellets than for lumpy SiO2 for the same molar ratio and heating conditions. The two SiC polytypes used in the carbothermal reduction experiments as carbon reductants presented different reactivity.

Experimental Verification of Guided-Wave Lumped Circuits Using Waveguide Metamaterials

Science.gov (United States)

Li, Yue; Zhang, Zhijun

2018-04-01

Through the construction and characterization in microwave frequencies, we experimentally demonstrate our recently developed theory of waveguide lumped circuits, i.e., waveguide metatronics [Sci. Adv. 2, e1501790 (2016), 10.1126/sciadv.1501790], as a method to design subwavelength-scaled analog circuits. In the paradigm of waveguide metatronics, numbers of lumped inductors and capacitors are easily integrated functionally inside the waveguide, which is an irreplaceable transmission line in millimeter-wave and terahertz systems with the advantages of low radiation loss and low crosstalk. An example of multiple-ordered metatronic filters with layered structures is fabricated utilizing the technique of substrate integrated waveguides, which can be easily constructed by the printed-circuit-board process. The materials used in the construction are also typical microwave materials with positive permittivity, low loss, and negligible dispersion, imitating the plasmonic materials with negative permittivity in the optical domain. The results verify the theory of waveguide metatronics, which provides an efficient platform of functional lumped circuit design for guided-wave processing.

Uncertainty quantification in flux balance analysis of spatially lumped and distributed models of neuron-astrocyte metabolism.

Science.gov (United States)

Calvetti, Daniela; Cheng, Yougan; Somersalo, Erkki

2016-12-01

Identifying feasible steady state solutions of a brain energy metabolism model is an inverse problem that allows infinitely many solutions. The characterization of the non-uniqueness, or the uncertainty quantification of the flux balance analysis, is tantamount to identifying the degrees of freedom of the solution. The degrees of freedom of multi-compartment mathematical models for energy metabolism of a neuron-astrocyte complex may offer a key to understand the different ways in which the energetic needs of the brain are met. In this paper we study the uncertainty in the solution, using techniques of linear algebra to identify the degrees of freedom in a lumped model, and Markov chain Monte Carlo methods in its extension to a spatially distributed case. The interpretation of the degrees of freedom in metabolic terms, more specifically, glucose and oxygen partitioning, is then leveraged to derive constraints on the free parameters to guarantee that the model is energetically feasible. We demonstrate how the model can be used to estimate the stoichiometric energy needs of the cells as well as the household energy based on the measured oxidative cerebral metabolic rate of glucose and glutamate cycling. Moreover, our analysis shows that in the lumped model the net direction of lactate dehydrogenase (LDH) in the cells can be deduced from the glucose partitioning between the compartments. The extension of the lumped model to a spatially distributed multi-compartment setting that includes diffusion fluxes from capillary to tissue increases the number of degrees of freedom, requiring the use of statistical sampling techniques. The analysis of the distributed model reveals that some of the conclusions valid for the spatially lumped model, e.g., concerning the LDH activity and glucose partitioning, may no longer hold.

Simulation Model of Membrane Gas Separator Using Aspen Custom Modeler

Energy Technology Data Exchange (ETDEWEB)

Song, Dong-keun [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); Shin, Gahui; Yun, Jinwon; Yu, Sangseok [Chungnam Nat’l Univ., Daejeon (Korea, Republic of)

2016-12-15

Membranes are used to separate pure gas from gas mixtures. In this study, three different types of mass transport through a membrane were developed in order to investigate the gas separation capabilities of a membrane. The three different models typically used are a lumped model, a multi-cell model, and a discretization model. Despite the multi-cell model producing similar results to a discretization model, the discretization model was selected for this investigation, due to the cell number dependence of a multi-cell model. The mass transport model was then used to investigate the effects of pressure difference, flow rate, total exposed area, and permeability. The results showed that the pressure difference increased with the stage cut, but the selectivity was a trade-off for the increasing pressure difference. Additionally, even though permeability is an important parameter, the selectivity and stage cut of the membrane converged as permeability increased.

24 CFR 570.513 - Lump sum drawdown for financing of property rehabilitation activities.

Science.gov (United States)

2010-04-01

... DEVELOPMENT BLOCK GRANTS Grant Administration § 570.513 Lump sum drawdown for financing of property... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Lump sum drawdown for financing of property rehabilitation activities. 570.513 Section 570.513 Housing and Urban Development Regulations...

Modelling of FCC (Fluid Catalytic Cracking) risers with six lumps; Modelo de elevadores de Unidades de Craqueamento Catalitico com cinetica de seis classes

Energy Technology Data Exchange (ETDEWEB)

Baldessar, Fabio; Negrao, Cezar O. Ribeiro; Palu, Claudia [Centro Federal de Educacao Tecnologica do Parana (CEFET-PR), Curitiba, PR (Brazil)

2004-07-01

The current work presents a mathematical model of an ascendant flow vertical reactor (riser) of a Fluid Catalytic Cracking Unit. The two-phase flow (gas-solid) and the cracking reactions are admitted one-dimensional and steady state. Mass, momentum and energy conservation equations are considered for each phase (solid and gas). A six-lump kinetic model is employed to evaluate gasoil, gasoline, GLP, fuel gas, light cycle oil and coke fractions. The model results are compared to experimental values from a pilot plant and to another model found in the literature. The results are in good agreement, showing the model has great potential. (author)

A distributed lumped active all-pass network configuration.

Science.gov (United States)

Huelsman, L. P.; Raghunath, S.

1972-01-01

In this correspondence a new and interesting distributed lumped active network configuration that realizes an all-pass network function is described. A design chart for determining the values of the network elements is included.

The frequency of malignancy in breast lumps on fnac in females under 35 years of age

International Nuclear Information System (INIS)

Iqbal, M.; Iqbal, M.

2014-01-01

Breast carcinoma is one of the common malignancies in females and its incidence is increasing in younger age. Diagnosis of carcinoma breast includes clinical evaluation, imaging and pathology. Fine Needle Aspiration Cytology is the first line pathological investigation in the diagnosis with excellent results. Objective: To determine the frequency of malignancy in breast lumps on FNAC in females under 35 years of age. Descriptive cross sectional study. Setting:Department of pathology Fatima Jinnah Medical College (FJMC), Lahore. Duration: Six months from 20th July, 2011 till 20th January, 2012.Methods: 150 female patients 35 years of age or less, presenting to the OPD and Indoor of Sir Ganga Ram Hospital Lahore, an affiliated hospital of FJMC Lahore, with breast lumps were included in the study. Demographic features and consent of the patients were noted. FNAC of the patients was performed as per advice of the consultant. Diagnosis of malignant cases was further confirmed on histology.Results: Out of all, 124 lumps (82.7%) were benign and 26 lumps (17.3%) were malignant. Amongst the benign lumps, 77(62.1%) were fibroadenomas, 28(22.6%) were fibrocystic changes, 08(06.5%) were inflammatory lesions, 07(05.6%) showed pyogenic abscess and 04 lumps (03.2%) were galactoceles. Amongst the malignant lumps, 22(84.6%) were ductal carcinoma, 02(07.7%) colloid carcinoma and 02(07.7%) were malignant phylloides. Conclusions: The frequency of malignancy in breast lumps in Pakistan is significantly high in females under 35 years of age. Appropriate measures are needed for prevention and early diagnosis and treatment in young females. (author)

CLINICO PATHOLOGICAL STUDY OF BENIGN BREAST LUMP – A HOSPITAL BASED STUDY

Directory of Open Access Journals (Sweden)

Anindita

2016-03-01

Full Text Available BACKGROUND Despite the fact that in majority of cases the initial symptom of benign breast disease is a lump, which can be easily detected by the patient herself by self-examination they generally present at a very late stage and this poses a great difficulty in their management. Early and appropriate diagnosis of breast disease is of utmost importance. AIM The aim of the study was to find out the relative frequency and commonest site of occurrence of benign breast disorder and their relationship with age, parity, menstrual cycle, and socio-economic status and also to find out the accuracy of investigative procedures in their diagnosis. DESIGN This is a cross sectional, interventional. Hospital based study. MATERIALS AND METHOD This study was done in 58 female patients in the age group 10 yrs. to 55 yrs. presenting with clinically benign breast lumps randomly chosen from outpatient department and indoor wards of The Calcutta Medical Research Institute, Kolkata. After taking an accurate history and proper clinical examination these patients were sequentially studied by radiological methods (Ultrasonography and mammography, fine needle aspiration cytology (FNAC and histopathology of removed specimen. Patients were enquired about their age, chief complaints, menstrual history, and use of oral pill, marital status, parity, lactation and socioeconomic status. RESULTS 79% of the benign breast lumps were found to be between 10–35 years, Fibro adenoma being the commonest one (41.38% and fibrocystic disease the second most common (29.31%. Breast lump were more common among unmarried and nulliparous females (48.27%, commonest site being upper and outer quadrant (38.8%. 69% patients were associated with an abnormal menstrual status. 76% of the cases were accurately diagnosed by clinical examination, 70% by mammography, 88% by FNAC and 84% by ultrasonography. CONCLUSION This clinicopathological study of benign breast lump is a small endeavour on our part

Investigation on gas medium parameters for an ArF excimer laser through orthogonal experimental design

Science.gov (United States)

Song, Xingliang; Sha, Pengfei; Fan, Yuanyuan; Jiang, R.; Zhao, Jiangshan; Zhou, Yi; Yang, Junhong; Xiong, Guangliang; Wang, Yu

2018-02-01

Due to complex kinetics of formation and loss mechanisms, such as ion-ion recombination reaction, neutral species harpoon reaction, excited state quenching and photon absorption, as well as their interactions, the performance behavior of different laser gas medium parameters for excimer laser varies greatly. Therefore, the effects of gas composition and total gas pressure on excimer laser performance attract continual research studies. In this work, orthogonal experimental design (OED) is used to investigate quantitative and qualitative correlations between output laser energy characteristics and gas medium parameters for an ArF excimer laser with plano-plano optical resonator operation. Optimized output laser energy with good pulse to pulse stability can be obtained effectively by proper selection of the gas medium parameters, which makes the most of the ArF excimer laser device. Simple and efficient method for gas medium optimization is proposed and demonstrated experimentally, which provides a global and systematic solution. By detailed statistical analysis, the significance sequence of relevant parameter factors and the optimized composition for gas medium parameters are obtained. Compared with conventional route of varying single gas parameter factor sequentially, this paper presents a more comprehensive way of considering multivariables simultaneously, which seems promising in striking an appropriate balance among various complicated parameters for power scaling study of an excimer laser.

Using a lumped conceptual hydrological model for five different catchments in Sweden

OpenAIRE

Ekenberg, Madeleine

2016-01-01

Hydrological models offer powerful tools for understanding and predicting. In this thesis we havereviewed the advantages and disadvantages of physically based distributed hydrological models andconceptually lumped hydrological models. Based on that review, we went into depth and developed aMATLAB code to test if a simple conceptual lumped hydrological model, namely GR2M, wouldperform satisfactory for five different catchments in different parts of Sweden. The model had ratherunsatisfactory re...

APPROACH TO THE DIAGNOSIS OF A BREAST LUMP

African Journals Online (AJOL)

breast cancer in any woman, irrespective of age.1,2 Fortunately, the vast majority of breast lumps are ... malignant breast lesions can be diagnosed in this way. When all aspects ... ultrasonography is the preferred modality for women under 35 ...

Uncovering and testing the fuzzy clusters based on lumped Markov chain in complex network.

Science.gov (United States)

Jing, Fan; Jianbin, Xie; Jinlong, Wang; Jinshuai, Qu

2013-01-01

Identifying clusters, namely groups of nodes with comparatively strong internal connectivity, is a fundamental task for deeply understanding the structure and function of a network. By means of a lumped Markov chain model of a random walker, we propose two novel ways of inferring the lumped markov transition matrix. Furthermore, some useful results are proposed based on the analysis of the properties of the lumped Markov process. To find the best partition of complex networks, a novel framework including two algorithms for network partition based on the optimal lumped Markovian dynamics is derived to solve this problem. The algorithms are constructed to minimize the objective function under this framework. It is demonstrated by the simulation experiments that our algorithms can efficiently determine the probabilities with which a node belongs to different clusters during the learning process and naturally supports the fuzzy partition. Moreover, they are successfully applied to real-world network, including the social interactions between members of a karate club.

Mixed lump-kink and rogue wave-kink solutions for a (3 + 1) -dimensional B-type Kadomtsev-Petviashvili equation in fluid mechanics

Science.gov (United States)

Hu, Cong-Cong; Tian, Bo; Wu, Xiao-Yu; Yuan, Yu-Qiang; Du, Zhong

2018-02-01

Under investigation is a (3 + 1) -dimensional B-type Kadomtsev-Petviashvili equation, which describes the weakly dispersive waves in a fluid. Via the Hirota method and symbolic computation, we obtain the mixed lump-kink and mixed rogue wave-kink solutions. Through the mixed lump-kink solutions, we observe three different phenomena between a lump and one kink. For the fusion phenomenon, a lump and a kink are merged with the lump's energy transferring into the kink gradually, until the lump merges into the kink completely. Fission phenomenon displays that a lump separates from a kink. The last phenomenon shows that a lump travels together with a kink with their amplitudes unchanged. In addition, we graphically study the interaction between a rogue wave and a pair of the kinks. It can be observed that the rogue wave arises from one kink and disappears into the other kink. At certain time, the amplitude of the rogue wave reaches the maximum.

Optimal Component Lumping: problem formulation and solution techniques

DEFF Research Database (Denmark)

Lin, Bao; Leibovici, Claude F.; Jørgensen, Sten Bay

2008-01-01

This paper presents a systematic method for optimal lumping of a large number of components in order to minimize the loss of information. In principle, a rigorous composition-based model is preferable to describe a system accurately. However, computational intensity and numerical issues restrict ...

Fission and fusion interaction phenomena of mixed lump kink solutions for a generalized (3+1)-dimensional B-type Kadomtsev-Petviashvili equation

Science.gov (United States)

Liu, Yaqing; Wen, Xiaoyong

2018-05-01

In this paper, a generalized (3+1)-dimensional B-type Kadomtsev-Petviashvili (gBKP) equation is investigated by using the Hirota’s bilinear method. With the aid of symbolic computation, some new lump, mixed lump kink and periodic lump solutions are derived. Based on the derived solutions, some novel interaction phenomena like the fission and fusion interactions between one lump soliton and one kink soliton, the fission and fusion interactions between one lump soliton and a pair of kink solitons and the interactions between two periodic lump solitons are discussed graphically. Results might be helpful for understanding the propagation of the shallow water wave.

Impact of Reservoir Fluid Saturation on Seismic Parameters: Endrod Gas Field, Hungary

Science.gov (United States)

El Sayed, Abdel Moktader A.; El Sayed, Nahla A.

2017-12-01

Outlining the reservoir fluid types and saturation is the main object of the present research work. 37 core samples were collected from three different gas bearing zones in the Endrod gas field in Hungary. These samples are belonging to the Miocene and the Upper - Lower Pliocene. These samples were prepared and laboratory measurements were conducted. Compression and shear wave velocity were measured using the Sonic Viewer-170-OYO. The sonic velocities were measured at the frequencies of 63 and 33 kHz for compressional and shear wave respectively. All samples were subjected to complete petrophysical investigations. Sonic velocities and mechanical parameters such as young’s modulus, rigidity, and bulk modulus were measured when samples were saturated by 100%-75%-0% brine water. Several plots have been performed to show the relationship between seismic parameters and saturation percentages. Robust relationships were obtained, showing the impact of fluid saturation on seismic parameters. Seismic velocity, Poisson’s ratio, bulk modulus and rigidity prove to be applicable during hydrocarbon exploration or production stages. Relationships among the measured seismic parameters in gas/water fully and partially saturated samples are useful to outline the fluid type and saturation percentage especially in gas/water transitional zones.

Intermittent reservoir daily-inflow prediction using lumped and ...

Indian Academy of Sciences (India)

For the present case study considered, both MLR and ARIMA models performed ... is to be remembered that the transformation of ... Multi-linear regression; lumped and distributed data; time-series models; cause-effect ... flow data are short for adequate system study. ..... that the standard deviation, skewness, kurtosis.

Lumped thermal capacitance analysis of transient heat conduction ...

African Journals Online (AJOL)

Lumped thermal capacitance analysis has been undertaken to investigate the transient temperature variations, associated induced thermal stress distributions, and the structural integrity of Ghana Research Reactor-1 (GHAR R-1) vessel after 15 years of operation. The beltline configuration of the cylindrical vessel of the ...

14C chronology of the oldest Scandinavian church in use. An AMS/PIXE study of lime lump carbonate in the mortar

International Nuclear Information System (INIS)

Lindroos, Alf; Ranta, Heikki; 14C Dating Laboratory, Department of Physics and Astronomy, University of Aarhus (Denmark))" data-affiliation=" (AMS 14C Dating Laboratory, Department of Physics and Astronomy, University of Aarhus (Denmark))" >Heinemeier, Jan; Lill, Jan-Olof

2014-01-01

Mortar dating was applied to newly revealed, original mortar in the church of Dalby in Scania, southern Sweden which is considered to be the oldest still standing church in Scandinavia. Small white lime lumps were sampled by chipping from the supporting pillars in the interior of the church. Special emphasis was in sampling lime lumps because the church is situated in the Scania limestone area and aggregate limestone contamination was anticipated in the bulk mortars. Earlier studies have, however, shown that lime lumps do not contain aggregate material but only possible limestone rests from incomplete calcination. The sampled material was prepared for radiocarbon AMS dating. The carbonate in the lime lumps was hydrolyzed according to the sequential leaching technique developed for the Århus 14 C laboratory in Denmark. Prior to the hydrolysis the lime lumps were examined for dead-carbon contamination using a stereo microscope and cathodoluminescence. The lime lumps displayed heterogeneous carbonate luminescence. This is, however, common and it was not considered a problem because carbonate growth in changing pH/Eh conditions often leads to changing luminescence colors. Two lumps had little dead carbon contamination and an early second millennium 14 C signature. One lump, however, seemed to be heavily contaminated with dead carbon. Since the sample passed the microscopic screening, the leftovers of the lump was subjected to PIXE analysis and compared with the other two lumps. The well-defined, early 2nd millennium 14 C age of the lime lumps of this particular church is an important contribution to the discussion on stone church chronology in Scandinavia

Network optimization including gas lift and network parameters under subsurface uncertainty

Energy Technology Data Exchange (ETDEWEB)

Schulze-Riegert, R.; Baffoe, J.; Pajonk, O. [SPT Group GmbH, Hamburg (Germany); Badalov, H.; Huseynov, S. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). ITE; Trick, M. [SPT Group, Calgary, AB (Canada)

2013-08-01

Optimization of oil and gas field production systems poses a great challenge to field development due to complex and multiple interactions between various operational design parameters and subsurface uncertainties. Conventional analytical methods are capable of finding local optima based on single deterministic models. They are less applicable for efficiently generating alternative design scenarios in a multi-objective context. Practical implementations of robust optimization workflows integrate the evaluation of alternative design scenarios and multiple realizations of subsurface uncertainty descriptions. Production or economic performance indicators such as NPV (Net Present Value) are linked to a risk-weighted objective function definition to guide the optimization processes. This work focuses on an integrated workflow using a reservoir-network simulator coupled to an optimization framework. The work will investigate the impact of design parameters while considering the physics of the reservoir, wells, and surface facilities. Subsurface uncertainties are described by well parameters such as inflow performance. Experimental design methods are used to investigate parameter sensitivities and interactions. Optimization methods are used to find optimal design parameter combinations which improve key performance indicators of the production network system. The proposed workflow will be applied to a representative oil reservoir coupled to a network which is modelled by an integrated reservoir-network simulator. Gas-lift will be included as an explicit measure to improve production. An objective function will be formulated for the net present value of the integrated system including production revenue and facility costs. Facility and gas lift design parameters are tuned to maximize NPV. Well inflow performance uncertainties are introduced with an impact on gas lift performance. Resulting variances on NPV are identified as a risk measure for the optimized system design. A

Role of cytological grading in the management of breast lump

International Nuclear Information System (INIS)

Mehmood, A.; Ahmed, M.; Jamal, S.

2003-01-01

Objective: To evaluate the fine needle aspiration (FNA) smears of the breast lumps using the cytological evaluation system (C1 to C5) as practiced in the National Breast Screening Programme in the UK. Results: A total of 75 patients of lump breast were included in the project. The age range was 13-75 years with a peak incidence in the 3rd decade. There were 70 (93.3%) females and 5 (6.6%) male cases. Of the total 75 cases, 7 were designated C1, 45 C2, 5 C3, 7 C4 and 11 C5. In surgical biopsies, all the 45 cases designated as C2 proved to be benign with fibroadenoma and fibrocystic change as predominant lesions. All 11 designated C5 proved to be malignant; whereas, of the 5 cases labeled as C3, 4 were benign and one was malignant and out of seven C4 cases, 5 came out as malignant and 2 proved benign. Conclusion: the fine needle aspiration of lump breast has a sensitivity of 94.1%, specificity of 96.0% and accuracy of 95.5%. The C1-C5 grading system is practical, flexible, and gives room for expression of opinion by cytopathologist and easily interpreted by clincians. (author)

Correlating Gas Transport Parameters and X-ray Computed Tomography Measurements in Porous Media

DEFF Research Database (Denmark)

Naveed, Muhammad; Hamamoto, Shoichiro; Kawamoto, Ken

2013-01-01

physical processes. The objective of this study was to characterize the relationships between gas transport parameters and soil-pore geometry revealed by X-ray CT. Sands of different shapes with a mean particle diameter (d50) ranging from 0.19 to 1.51 mm were used as porous media under both air...... was found between α and tortuosity calculated from gas transport parameters (Equation (Uncited) Image Tools), indicating that gas dispersivity has a linear and inverse relationship with gas diffusivity. A linear relationship was also found between ka and d50/TUMS2, indicating a strong dependency of ka...

Dynamics of lumps and dark-dark solitons in the multi-component long-wave-short-wave resonance interaction system

Science.gov (United States)

Rao, Jiguang; Porsezian, Kuppuswamy; He, Jingsong; Kanna, Thambithurai

2018-01-01

General semi-rational solutions of an integrable multi-component (2+1)-dimensional long-wave-short-wave resonance interaction system comprising multiple short waves and a single long wave are obtained by employing the bilinear method. These solutions describe the interactions between various types of solutions, including line rogue waves, lumps, breathers and dark solitons. We only focus on the dynamical behaviours of the interactions between lumps and dark solitons in this paper. Our detailed study reveals two different types of excitation phenomena: fusion and fission. It is shown that the fundamental (simplest) semi-rational solutions can exhibit fission of a dark soliton into a lump and a dark soliton or fusion of one lump and one dark soliton into a dark soliton. The non-fundamental semi-rational solutions are further classified into three subclasses: higher-order, multi- and mixed-type semi-rational solutions. The higher-order semi-rational solutions show the process of annihilation (production) of two or more lumps into (from) one dark soliton. The multi-semi-rational solutions describe N(N≥2) lumps annihilating into or producing from N-dark solitons. The mixed-type semi-rational solutions are a hybrid of higher-order semi-rational solutions and multi-semi-rational solutions. For the mixed-type semi-rational solutions, we demonstrate an interesting dynamical behaviour that is characterized by partial suppression or creation of lumps from the dark solitons.

Dynamics of lumps and dark-dark solitons in the multi-component long-wave-short-wave resonance interaction system.

Science.gov (United States)

Rao, Jiguang; Porsezian, Kuppuswamy; He, Jingsong; Kanna, Thambithurai

2018-01-01

General semi-rational solutions of an integrable multi-component (2+1)-dimensional long-wave-short-wave resonance interaction system comprising multiple short waves and a single long wave are obtained by employing the bilinear method. These solutions describe the interactions between various types of solutions, including line rogue waves, lumps, breathers and dark solitons. We only focus on the dynamical behaviours of the interactions between lumps and dark solitons in this paper. Our detailed study reveals two different types of excitation phenomena: fusion and fission. It is shown that the fundamental (simplest) semi-rational solutions can exhibit fission of a dark soliton into a lump and a dark soliton or fusion of one lump and one dark soliton into a dark soliton. The non-fundamental semi-rational solutions are further classified into three subclasses: higher-order, multi- and mixed-type semi-rational solutions. The higher-order semi-rational solutions show the process of annihilation (production) of two or more lumps into (from) one dark soliton. The multi-semi-rational solutions describe N ( N ≥2) lumps annihilating into or producing from N -dark solitons. The mixed-type semi-rational solutions are a hybrid of higher-order semi-rational solutions and multi-semi-rational solutions. For the mixed-type semi-rational solutions, we demonstrate an interesting dynamical behaviour that is characterized by partial suppression or creation of lumps from the dark solitons.

Lumped Mass Modeling for Local-Mode-Suppressed Element Connectivity

DEFF Research Database (Denmark)

Joung, Young Soo; Yoon, Gil Ho; Kim, Yoon Young

2005-01-01

connectivity parameterization (ECP) is employed. On the way to the ultimate crashworthy structure optimization, we are now developing a local mode-free topology optimization formulation that can be implemented in the ECP method. In fact, the local mode-freeing strategy developed here can be also used directly...... experiencing large structural changes, appears to be still poor. In ECP, the nodes of the domain-discretizing elements are connected by zero-length one-dimensional elastic links having varying stiffness. For computational efficiency, every elastic link is now assumed to have two lumped masses at its ends....... Choosing appropriate penalization functions for lumped mass and link stiffness is important for local mode-free results. However, unless the objective and constraint functions are carefully selected, it is difficult to obtain clear black-and-white results. It is shown that the present formulation is also...

Management of breast lumps in Maiduguri, Nigeria

Directory of Open Access Journals (Sweden)

Ali Nuhu

2014-01-01

Full Text Available Background: Reported changes in the demography, modes of presentation and histological variants of tumors of the breast have been published in developed and some developing countries. Although benign lesions have persistently accounted for most breast tumors, the incidence of malignant breast lesion in young women in sub-Saharan Africa has been disturbingly high. We reviewed the demographics, pattern and management of breast lumps excised at University of Maiduguri Teaching Hospital (UMTH over a 6 year period. Patients and Methods: A retrospective study of patients with breast lumps at UMTH was carried out between January 2005 and December 2010. Details of their bio-data, clinical, and histopathology details were analyzed using descriptive statistics. Results: A total of 913 patients, comprising 887 females (97.2% and 26 males (2.8% were reviewed. The mean age was 33.1 ± 14.6 years (range: 12-80 years and the mean duration of symptoms was 8 ± 2.14 months (range: 2-23 months. 359 (39.3% were malignant and 577 (63.2% were benign. The mean ages of women and men with invasive carcinomas of the breast were 45.58 ± 13.22 and 49.75 ± 18.28 years, respectively. The mean age of women with benign breast disease was 28.4 ± 10.0 for fibrocystic disease and 21.8 ± 5.31 years for fibroadenoma. Mode of presentations included ulcers (8.7%, axillary lymph node enlargement (30.0%, nipple discharge (13.0% and breast pain (21.7%. The most common histological diagnoses were carcinoma of the breast, N = 340 (37.2%, fibroadenoma, N = 276 (30.2% and fibrocystic disease, N = 199 (21.8%. The least common pathology was tuberculosis of the breast, N = 6; (0.7%. Conclusion: Though benign diseases are still more common, a high percentage of breast lumps in Maiduguri are due to malignant disease and this is frequent in younger women.

Towards a lumped reaction model for future designer fuels

Energy Technology Data Exchange (ETDEWEB)

Vandersickel, A.; Wright, Y.M.; Boulouchos, K. [ETH Zurich, Aerothermochemistry and Combustion Systems Laboratory, Zurich (Switzerland). Inst. of Energy Technology

2009-07-01

The homogeneous charge compression ignition (HCCI) is one of the most promising engine processes to simultaneously reduce nitrogen oxide and soot emissions. However, its applicability is hindered by its relatively limited operating range. Designer fuels offer unique possibilities for tailoring evaporation and auto-ignition properties, offering a means to control and expand the HCCI operation range. The identification of HCCI relevant fuel properties as well as the definition of a new fuel index able to describe a fuels suitability for HCCI was required in order to develop such designer fuels. This paper discussed a numerical and experimental investigation of a large set of technical fuels covering a wide range of properties. The paper discussed mechanism development approaches, optimization of the lumped mechanism, and and results. Zheng's 7-step reaction mechanism was successfully coupled with a genetic optimization algorithm and fitted to n-heptane ignition delay data. It was concluded that the presented coupled approach could improve the predictive quality of the model and demonstrate that the Zheng model was sufficiently elaborate to emulate the influence of temperature, pressure, exhaust gas recirculation and lambda on ignition. 8 refs., 1 tab., 3 figs.

Towards a lumped reaction model for future designer fuels

International Nuclear Information System (INIS)

Vandersickel, A.; Wright, Y.M.; Boulouchos, K.

2009-01-01

The homogeneous charge compression ignition (HCCI) is one of the most promising engine processes to simultaneously reduce nitrogen oxide and soot emissions. However, its applicability is hindered by its relatively limited operating range. Designer fuels offer unique possibilities for tailoring evaporation and auto-ignition properties, offering a means to control and expand the HCCI operation range. The identification of HCCI relevant fuel properties as well as the definition of a new fuel index able to describe a fuels suitability for HCCI was required in order to develop such designer fuels. This paper discussed a numerical and experimental investigation of a large set of technical fuels covering a wide range of properties. The paper discussed mechanism development approaches, optimization of the lumped mechanism, and and results. Zheng's 7-step reaction mechanism was successfully coupled with a genetic optimization algorithm and fitted to n-heptane ignition delay data. It was concluded that the presented coupled approach could improve the predictive quality of the model and demonstrate that the Zheng model was sufficiently elaborate to emulate the influence of temperature, pressure, exhaust gas recirculation and lambda on ignition. 8 refs., 1 tab., 3 figs.

29 CFR Appendix C to Part 4022 - Lump Sum Interest Rates for Private-Sector Payments

Science.gov (United States)

2010-07-01

... 29 Labor 9 2010-07-01 2010-07-01 false Lump Sum Interest Rates for Private-Sector Payments C Appendix C to Part 4022 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY... Appendix C to Part 4022—Lump Sum Interest Rates for Private-Sector Payments [In using this table: (1) For...

Comparison the Results of Numerical Simulation And Experimental Results for Amirkabir Plasma Focus Facility

Science.gov (United States)

Goudarzi, Shervin; Amrollahi, R.; Niknam Sharak, M.

2014-06-01

In this paper the results of the numerical simulation for Amirkabir Mather-type Plasma Focus Facility (16 kV, 36μF and 115 nH) in several experiments with Argon as working gas at different working conditions (different discharge voltages and gas pressures) have been presented and compared with the experimental results. Two different models have been used for simulation: five-phase model of Lee and lumped parameter model of Gonzalez. It is seen that the results (optimum pressures and current signals) of the Lee model at different working conditions show better agreement than lumped parameter model with experimental values.

Comparison the results of numerical simulation and experimental results for Amirkabir plasma focus facility

International Nuclear Information System (INIS)

Goudarzi, Shervin; Amrollahi, R; Sharak, M Niknam

2014-01-01

In this paper the results of the numerical simulation for Amirkabir Mather-type Plasma Focus Facility (16 kV, 36μF and 115 nH) in several experiments with Argon as working gas at different working conditions (different discharge voltages and gas pressures) have been presented and compared with the experimental results. Two different models have been used for simulation: five-phase model of Lee and lumped parameter model of Gonzalez. It is seen that the results (optimum pressures and current signals) of the Lee model at different working conditions show better agreement than lumped parameter model with experimental values.

Approach to the diagnosis of a breast lump

African Journals Online (AJOL)

Generally, the older the woman, the greater the degree of suspicion and the more aggressive the ... When patients present with a history of a breast lump, the first crucial step is to ... A past history of a breast biopsy showing atypical hyperplasia, a family history of ... ultrasonography is the preferred modality for women under ...

Axillary silicone lymphadenopathy presenting with a lump and altered sensation in the breast: a case report

Directory of Open Access Journals (Sweden)

Adams Simon T

2009-03-01

Full Text Available Abstract Introduction Silicone lymphadenopathy is a rare but recognised complication of procedures involving the use of silicone. It has a poorly understood mechanism but is thought to occur following the transportation of silicone particles from silicone-containing prostheses to lymph nodes by macrophages. Case presentation We report of a case involving a 35-year-old woman who presented to the breast clinic with a breast lump and altered sensation below her left nipple 5 years after bilateral cosmetic breast augmentations. A small lump was detected inferior to the nipple but clinical examination and initial ultrasound investigation showed both implants to be intact. However, mammography and magnetic resonance imaging of both breasts revealed both intracapsular and extracapsular rupture of the left breast prosthesis. The patient went on to develop a flu-like illness and tender lumps in the left axilla and right mastoid regions. An excision biopsy of the left axillary lesion and replacement of the ruptured implant was performed. Subsequent histological analysis showed that the axillary lump was a lymph node containing large amounts of silicone. Conclusion The exclusion of malignancy remains the priority when dealing with lumps in the breast or axilla. Silicone lymphadenopathy should however be considered as a differential diagnosis in patients in whom silicone prostheses are present.

{sup 14}C chronology of the oldest Scandinavian church in use. An AMS/PIXE study of lime lump carbonate in the mortar

Energy Technology Data Exchange (ETDEWEB)

Lindroos, Alf, E-mail: alf.lindroos@abo.fi [Geology and Mineralogy, Department of Natural Sciences, Åbo Akademi University (Finland); Art History, Faculty of Art, Åbo Akademi University (Finland); Ranta, Heikki [Diocese of Lund, Church of Sweden (Sweden); Heinemeier, Jan [AMS " 1" 4C Dating Laboratory, Department of Physics and Astronomy, University of Aarhus (Denmark); Lill, Jan-Olof [Accelerator Laboratory, Turku PET Centre, Åbo Akademi University (Finland)

2014-07-15

Mortar dating was applied to newly revealed, original mortar in the church of Dalby in Scania, southern Sweden which is considered to be the oldest still standing church in Scandinavia. Small white lime lumps were sampled by chipping from the supporting pillars in the interior of the church. Special emphasis was in sampling lime lumps because the church is situated in the Scania limestone area and aggregate limestone contamination was anticipated in the bulk mortars. Earlier studies have, however, shown that lime lumps do not contain aggregate material but only possible limestone rests from incomplete calcination. The sampled material was prepared for radiocarbon AMS dating. The carbonate in the lime lumps was hydrolyzed according to the sequential leaching technique developed for the Århus {sup 14}C laboratory in Denmark. Prior to the hydrolysis the lime lumps were examined for dead-carbon contamination using a stereo microscope and cathodoluminescence. The lime lumps displayed heterogeneous carbonate luminescence. This is, however, common and it was not considered a problem because carbonate growth in changing pH/Eh conditions often leads to changing luminescence colors. Two lumps had little dead carbon contamination and an early second millennium {sup 14}C signature. One lump, however, seemed to be heavily contaminated with dead carbon. Since the sample passed the microscopic screening, the leftovers of the lump was subjected to PIXE analysis and compared with the other two lumps. The well-defined, early 2nd millennium {sup 14}C age of the lime lumps of this particular church is an important contribution to the discussion on stone church chronology in Scandinavia.

Drift-flux parameters for upward gas flow in stagnant liquid

International Nuclear Information System (INIS)

Kataoka, Yoshiyuki; Suzuki, Hiroaki; Murase, Michio

1987-01-01

The drift-flux model is widely used for gas-liquid two phase flow analysis, because it is applicable to various flow patterns and a wide range of void fractions. The drift-flux parameters for upward gas flow in stagnant liquid, however, have not been well examined. In this study, the distribution parameter C o and the drift velocity V gj for stagnant liquid were derived from the void fraction correlation and boundary conditions of drift-flux parameters, and then compared with C o and V gj for high liquid velocities. Also using the two region model where a circular flow area was divided into an inner region of cocurrent up-flow and an outer annulus region of liquid down flow, C o and V gj for stagnant liquid and for high liquid velocity were compared. The results showed that C o values for stagnant liquid were larger than values for high liquid velocity, while V gj values were almost the same for both cases. (author)

Lumped impulses, discrete displacements and a moving load analysis

NARCIS (Netherlands)

Kok, A.W.M.

1997-01-01

Finite element models are usually presented as relations between lumped forces and discrete displacements. Mostly finite element models are found by the elaboration of the method of the virtual work - which is a special case of the Galerkin's variational principle -. By application of Galerkin's

29 CFR 4044.75 - Other lump sum benefits.

Science.gov (United States)

2010-07-01

... sum benefits. The value of a lump sum benefit which is not covered under § 4044.73 or § 4044.74 is equal to— (a) The value under the qualifying bid, if an insurer provides the benefit; or (b) The present value of the benefit as of the date of distribution, determined using reasonable actuarial assumptions...

Leaks, Lumps, and Lines: Stigma and Women's Bodies

Science.gov (United States)

Chrisler, Joan C.

2011-01-01

Women's bodies have often been positioned in art and popular culture as monstrous or defiled and women's bodily products (e.g., menstrual fluid, breast milk) as disgusting. This framing has led to the stigmatization of aspects of women's bodies (e.g., leaking fluids, lumps of fat, and lines in the skin that indicate aging), especially those…

Comparison of the AWA lumped-circuit model of electrical discharges with empirical data

International Nuclear Information System (INIS)

Maier, W.B. II; Kadish, A.; Robiscoe, R.T.

1990-01-01

The authors compare experimental data for three 1.7-m-long transient discharges with an AWA lumped- circuit discharge model in which the arc resistance is taken from the Arc Welder's Ansatz, R a = V*/|I |, where V* is a positive constant and I is the discharge current. In addition to the arc resistance, there is a small series resistance R present in the external circuit. A single value for each of R and V* is deduced from the data, and these values are used to characterize all three discharges. Adequate agreement with the experimental data is obtained; for example, the authors predict the proper number of current reversals for each discharge and abrupt termination of current flow after a finite time. The authors suggest that the AWA lumped circuit provides a better representation of the data than a standard lumped-circuit RLC model and hence is more useful as a tool for prediction and interpretation of discharges

From conservation laws to port-Hamiltonian representations of distributed-parameter systems

NARCIS (Netherlands)

Maschke, B.M.; van der Schaft, Arjan; Piztek, P.

Abstract: In this paper it is shown how the port-Hamiltonian formulation of distributed-parameter systems is closely related to the general thermodynamic framework of systems of conservation laws and closure equations. The situation turns out to be similar to the lumped-parameter case where the

Some error estimates for the lumped mass finite element method for a parabolic problem

KAUST Repository

Chatzipantelidis, P.

2012-01-01

We study the spatially semidiscrete lumped mass method for the model homogeneous heat equation with homogeneous Dirichlet boundary conditions. Improving earlier results we show that known optimal order smooth initial data error estimates for the standard Galerkin method carry over to the lumped mass method whereas nonsmooth initial data estimates require special assumptions on the triangulation. We also discuss the application to time discretization by the backward Euler and Crank-Nicolson methods. © 2011 American Mathematical Society.

Aggressive angiomyxoma presenting with huge abdominal lump: A case report

Science.gov (United States)

Kumar, Sanjeev; Agrawal, Nikhil; Khanna, Rahul; Khanna, AK

2008-01-01

Agressive angiomyxoma is a rare mesenchymal neoplasm. It mainly presents in females. We here present a case of angiomyxoma presenting as huge abdominal lump along with gluteal swelling. Case note is described along with brief review of literature. PMID:18755035

Extraction of diagnostic parameters from the transient response of a porous electro ceramic gas sensor

International Nuclear Information System (INIS)

Hossein-Babaei, F.; Orvatinia, M.

2004-01-01

A novel concept for the diagnosis of a pure target gas in air is presented. The method employs a resistive gas sensor with a mm-thick highly porous electro ceramic gas sensitive body. The diagnosis is based on the fact that the diffusion time of the target gas through the porous body would depend on its molecular properties. The transient response of the device was analyzed based on a diffusion reaction equation. The solutions of the equation were shown to be of diagnostic merits. Such a device was fabricated by partial sintering of a Zn O body formed by low pressure pressing. The transient responses of the device to methanol, ethanol, poropanol and butanol were recorded. The analytical data, and the diagnostic parameters were resulted as the fitting parameters. Comparison of the parameters obtained with those available from the calibration experiments afforded target gas identification

Incidence data for breast cancer among Yemeni female patients with palpable breast lumps.

Science.gov (United States)

Alsanabani, Jamila Ali; Gilan, Waleed; Saadi, Azzan Al

2015-01-01

To estimate the incidence of breast cancer in Yemeni female patients presenting with a breast mass. This retrospective study was carried out with 595 female patients with palpable breast lumps, attending to Alkuwait university hospital, Sana'a, Yemen. Triple assessment, including breast examination, mammography and biopsy (FNAC, core needle, or excision), for all patients were performed. The incidences of benign and malignant lesions was calculated. Some 160 (26.9%) of 595 patients had malignancies; 213 (35.8%) were fibroadenomas; 12 (2.0%) were fibrocystic change; 143 (24.03%) were inflammatory lesions (including mastitis and ductectasia); 62 (10.4%) were simple cysts, while 5 (0.8%) were phyllodes tumors. The mean age of patients with malignant lumps was 44.3 years. Among Yemeni female patients with palpable breast lumps, the rate of breast cancer is high, with occurrence at an earlier age than in Western countries. Improving breast cancer awareness programs and increasing breast cancer screening centers inb different areas of Yemen are needed to establish early diagnosis and offer early and optimal treatment.

Influences of lumped passes on welding residual stress of a thick-walled nuclear rotor steel pipe by multipass narrow gap welding

Energy Technology Data Exchange (ETDEWEB)

Tan, Long, E-mail: mse.longtan@gmail.com [State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Zhang, Jianxun; Zhuang, Dong [State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Liu, Chuan [Provincial Key Lab of Advanced Welding Technology, Jiangsu University of Science and Technology, Zhenjiang 212003 (China)

2014-07-01

Highlights: • The internal residual stress of the thick-walled pipe is measured by using the local removal blind hole method. • Two lumped-pass models are developed to reduce computational cost. • The effect of lumped passes on the welding residual stress is discussed. • Reasonable lumped-pass model can guarantee the accuracy and improve the computational efficiency. - Abstract: The purpose of this study is to investigate the effect of the lumped passes simulation on the distribution of residual stresses before and after heat treatment in a thick-walled nuclear power rotor pipe with a 89-pass narrow gap welding process. The local removal blind hole method was used to measure internal residual stress of the thick-walled pipe after post weld heat treatment (PWHT). Based on the ANSYS software, a two-dimensional axisymmetric finite element model is employed. Two lumped-pass models of M-5th model (five weld beads as one lumped pass) and M-10th model (ten weld beads as one lumped pass) were developed to reduce computational cost. Based on the results in this study, the distributions of residual stresses of a thick-walled welded pipe before and after PWHT are developed. Meanwhile, the distribution of the through-wall axial residual stress along the weld center line is demonstrated to be a self-equilibrating type. In addition, the investigation results show that reasonable and reliable lumped-pass model can not only guarantee the accuracy of the simulated results, but also improve the computational efficiency in the thermo-elastic–plastic FE analysis procedure. Therefore, from the viewpoint of engineering application the developed lumped-pass computational procedure is a promising and useful method to predict residual stress of large and complex welded structures.

Influences of lumped passes on welding residual stress of a thick-walled nuclear rotor steel pipe by multipass narrow gap welding

International Nuclear Information System (INIS)

Tan, Long; Zhang, Jianxun; Zhuang, Dong; Liu, Chuan

2014-01-01

Highlights: • The internal residual stress of the thick-walled pipe is measured by using the local removal blind hole method. • Two lumped-pass models are developed to reduce computational cost. • The effect of lumped passes on the welding residual stress is discussed. • Reasonable lumped-pass model can guarantee the accuracy and improve the computational efficiency. - Abstract: The purpose of this study is to investigate the effect of the lumped passes simulation on the distribution of residual stresses before and after heat treatment in a thick-walled nuclear power rotor pipe with a 89-pass narrow gap welding process. The local removal blind hole method was used to measure internal residual stress of the thick-walled pipe after post weld heat treatment (PWHT). Based on the ANSYS software, a two-dimensional axisymmetric finite element model is employed. Two lumped-pass models of M-5th model (five weld beads as one lumped pass) and M-10th model (ten weld beads as one lumped pass) were developed to reduce computational cost. Based on the results in this study, the distributions of residual stresses of a thick-walled welded pipe before and after PWHT are developed. Meanwhile, the distribution of the through-wall axial residual stress along the weld center line is demonstrated to be a self-equilibrating type. In addition, the investigation results show that reasonable and reliable lumped-pass model can not only guarantee the accuracy of the simulated results, but also improve the computational efficiency in the thermo-elastic–plastic FE analysis procedure. Therefore, from the viewpoint of engineering application the developed lumped-pass computational procedure is a promising and useful method to predict residual stress of large and complex welded structures

Lump Sum Moving Cost and Aggregate Office Space Use

NARCIS (Netherlands)

G. Romijn

1997-01-01

textabstractWhen firms decide to change office space use, in many instances this involves relocation. Relocation involves sizable costs to the firm that can to a large extent be characterized as lump sum, i.e. independent of the change in demand. In this paper we propose and solve a model of the

Primary Breast Tuberculosis Presenting as a Lump: A Rare Modern ...

African Journals Online (AJOL)

mammary area. A 25. year.old female, presented with a lump in the breast and infra.mammary area. She was having off and on fever without any other complaints. There was no positive family history. Primary breast tuberculosis was diagnosed on fine ...

Control of temperature distribution in a supercritical gas extraction tower

International Nuclear Information System (INIS)

Yoshida, M.; Matsumoto, S.; Honda, G.; Iwama, T.; Suzuki, Y.; Odagiri, S.

1989-01-01

A control scheme recently proposed by the authors is applied to the control of axial temperature distribution in a bench-scale supercritical-gas extractor. The extraction unit is constructed from a packed column 3 m long covered by a coaxial cylindrical casing. Although the actual structure of the extractor is very complicated, it is modeled by a simple double-pipe and therefore its mathematical model can be described by a pair of partial differential equations. The models are reduced to a lumped parameter system with a finite dimension by use of the finite Fourier transform technique. The controller is designed on the basis of the reduced model. An extended Kalman filter is used to estimate simultaneously the state variables and the unknown parameters. The results demonstrate that both the state estimation and the controller performance are satisfactory. This implies that the control scheme is very robust in spite of the incompleteness of the model used

effects of metal inert gas welding parameters on some mechanical ...

African Journals Online (AJOL)

EFFECTS OF METAL INERT GAS WELDING PARAMETERS ON SOME MECHANICAL PROPERTIES OF AUSTENITIC STAINLESS STEEL IN ACIDIC ... Design Expert Software, Scanning Electron Microscopy (SEM), Rockwell Hardness Test, Monsanto Tensometer and Izod Impact Test were used to determine the ...

Start-up of belt conveyors used for haulage of large lumps under difficult climatic conditions

Energy Technology Data Exchange (ETDEWEB)

Drobny, J

1979-01-01

Investigations are discussed carried out by the Research and Development Center for Brown Coal in Most, Czechoslovakia into effects of climate, weather and mass of coal lumps on reliability of belt conveyors in surface mines. Dirt buildup on the driving drums reduces friction and increases belt sliding hazards. Belt wear increases. Driving drum diameter, increased by the buildup, negatively influences load distribution among the electric motors of the drive system. In extreme cases belt wear and irregular load distribution cause belt failures. Methods for buildup removal used in Czechoslovakia and methods for protection of the return side of a conveyor are described. Effects of large mass of coal lumps and ice buildup on large lumps on the risk of belt damage (cuts, punctures etc,) are discussed. Recommendations for design of coal transfer points are made. 2 refs.

Galaxies and gas in a cold dark matter universe

Science.gov (United States)

Katz, Neal; Hernquist, Lars; Weinberg, David H.

1992-01-01

We use a combined gravity/hydrodynamics code to simulate the formation of structure in a random 22 Mpc cube of a cold dark matter universe. Adiabatic compression and shocks heat much of the gas to temperatures of 10 exp 6 - 10 exp 7 K, but a fraction of the gas cools radiatively to about 10 exp 4 K and condenses into discrete, highly overdense lumps. We identify these lumps with galaxies. The high-mass end of their baryonic mass function fits the form of the observed galaxy luminosity function. They retain independent identities after their dark halos merge, so gravitational clustering produces groups of galaxies embedded in relatively smooth envelopes of hot gas and dark matter. The galaxy correlation function is approximately an r exp -2.1 power law from separations of 35 kpc to 7 Mpc. Galaxy fluctuations are biased relative to dark matter fluctuations by a factor b about 1.5. We find no significant 'velocity bias' between galaxies and dark matter particles. However, virial analysis of the simulation's richest group leads to an estimated Omega of about 0.3, even though the simulation adopts Omega = 1.

Enhancing damping of gas bearings using linear parameter-varying control

DEFF Research Database (Denmark)

Theisen, Lukas Roy Svane; Niemann, Hans Henrik; Galeazzi, Roberto

2017-01-01

systems to regulate the injection pressure of the fluid. Due to the strong dependencies of system performance on system parameters, the sought controller should be robust over a large range of operational conditions. This paper addresses the damping enhancement of controllable gas bearings through robust...... control approaches. Through an extensive experimental campaign the paper evaluates two robust controllers, a linear parametervarying (LPV) controller and ∞ controller, on their capability to guarantee stability and performance of a gas bearing across the large operational envelopes in rotational speed...

20 CFR 725.521 - Commutation of payments; lump sum awards.

Science.gov (United States)

2010-04-01

... present value of future benefit payments commuted, computed at 4 percent true discount compounded annually... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Commutation of payments; lump sum awards. 725.521 Section 725.521 Employees' Benefits EMPLOYMENT STANDARDS ADMINISTRATION, DEPARTMENT OF LABOR...

An Analysis of the Effect of the U. S. Marine Corps' Lump Sum Selective Reenlistment Bonus Program on Reenlistment Decisions

National Research Council Canada - National Science Library

Barry, Robert

2001-01-01

... the impact of personal characteristics, civilian pay, unemployment, and the lump sum bonus on reenlistment decisions, Marine retention probabilities under the lump sum payment program are compared...

The constitutive distributed parameter model of multicomponent chemical processes in gas, fluid and solid phase

International Nuclear Information System (INIS)

Niemiec, W.

1985-01-01

In the literature of distributed parameter modelling of real processes is not considered the class of multicomponent chemical processes in gas, fluid and solid phase. The aim of paper is constitutive distributed parameter physicochemical model, constructed on kinetics and phenomenal analysis of multicomponent chemical processes in gas, fluid and solid phase. The mass, energy and momentum aspects of these multicomponent chemical reactions and adequate phenomena are utilized in balance operations, by conditions of: constitutive invariance for continuous media with space and time memories, reciprocity principle for isotropic and anisotropic nonhomogeneous media with space and time memories, application of definitions of following derivative and equation of continuity, to the construction of systems of partial differential constitutive state equations, in the following derivative forms for gas, fluid and solid phase. Couched in this way all physicochemical conditions of multicomponent chemical processes in gas, fluid and solid phase are new form of constitutive distributed parameter model for automatics and its systems of equations are new form of systems of partial differential constitutive state equations in sense of phenomenal distributed parameter control

Scattering of massless lumps and non-local charges in the two-dimensional classical non-linear sigma-model

International Nuclear Information System (INIS)

Luescher, M.; Pohlmeyer, K.

1977-09-01

Finite energy solutions of the field equations of the non-linear sigma-model are shown to decay asymptotically into massless lumps. By means of a linear eigenvalue problem connected with the field equations we then find an infinite set of dynamical conserved charges. They, however, do not provide sufficient information to decode the complicated scattering of lumps. (orig.) [de

The liquid lift: Looking natural without lumps

Directory of Open Access Journals (Sweden)

Iñigo de Felipe

2015-01-01

Full Text Available Context: Hyaluronic acid (HA is the most common filler used to rejuvenate. Today, a three-dimensional approach prevails over previous techniques in which this material was used in specific areas of the face such as the nasolabial fold, the marionette line, and the eye trough giving a strange appearance that does not look natural. Even with a volumizing purpose, the injection of HA can sometimes produce clinically detectable nodules or lumps where the filler is deposited. Aims: To develop a new technique of injecting HA that can provide more natural results and avoid the lumpiness and nodular appearance that sometimes occurs with the injection of HA. To detect whether mixing HA with diluted anesthetic agent modifies its behavior. Settings and Design: Prospective, case control, single-center study on a private clinic setting. Materials and Methods: Eighty six patients were enrolled in this study. All of them had a previous treatment with nondiluted HA using a needle at least a year before. Patients were injected with 8 mL of reticulated HA (RHA mixed with 6 mL of saline and 2 mL of anesthetic agent. The mixture was administered through a cannula inserted in the face, one at mid-cheek and another at frontal-temporal point of entry. Owing to the lifting effect of this mixture we called this procedure liquid lift (LL. Patients were evaluated 1 month, 6 months, and a year later and asked to compare the LL with previous experiences in terms of natural look, pain, and appearance of nodules. Statistical Analysis Used: Student′s t-test. Results: One month after the treatment, 83 out of 86 patients (96.5% thought LL produced a more natural look than the previous treatment with the needle. Sixty two (72% considered LL less painful than the previous treatment and only eight (9.3% could detect lumps or nodules 1 month after LL was performed compared with 46 (53.5% that described this problem with previous needle injections. The incidence of bruising was

Frequency Combs in a Lumped-Element Josephson-Junction Circuit

Science.gov (United States)

Khan, Saeed; Türeci, Hakan E.

2018-04-01

We investigate the dynamics of a microwave-driven Josephson junction capacitively coupled to a lumped-element L C oscillator. In the regime of driving where the Josephson junction can be approximated as a Kerr oscillator, this minimal nonlinear system has been previously shown to exhibit a bistability in phase and amplitude. In the present study, we characterize the full phase diagram and show that besides a parameter regime exhibiting bistability, there is also a regime of self-oscillations characterized by a frequency comb in its spectrum. We discuss the mechanism of comb generation which appears to be different from those studied in microcavity frequency combs and mode-locked lasers. We then address the fate of the comblike spectrum in the regime of strong quantum fluctuations, reached when nonlinearity becomes the dominant scale with respect to dissipation. We find that the nonlinearity responsible for the emergence of the frequency combs also leads to its dephasing, leading to broadening and ultimate disappearance of sharp spectral peaks. Our study explores the fundamental question of the impact of quantum fluctuations for quantum systems which do not possess a stable fixed point in the classical limit.

Lumped elements for RF and microwave circuits

CERN Document Server

Bahl, Inder

2003-01-01

Due to the unprecedented growth in wireless applications over the past decade, development of low-cost solutions for RF and microwave communication systems has become of great importance. This practical new book is the first comprehensive treatment of lumped elements, which are playing a critical role in the development of the circuits that make these cost-effective systems possible. The books offers you an in-depth understanding of the different types of RF and microwave circuit elements, including inductors, capacitors, resistors, transformers, via holes, airbridges, and crossovers. Support

distributed parameter model of spiral-wound sepralator for treatment of uranyl nitrate effluents

International Nuclear Information System (INIS)

El-Bialy, S.H; Elsherbiny, A.E.

2004-01-01

in this paper, mathematical formulation of spiral-wound sepralator was derived and applied for the treatment of effluent stream which is produced during nuclear fuel processing stage. the concentration of the stream has a value up to 200 ppm . cross-flow characteristic of both feed and permeate streams was taken into account and their mutual effects on the values of system variables were investigated. of course, such a flow pattern leads to a heterogeneous system which leads-in turn-to six partial differential equations, beside a set of algebraic equations. those were solved numerically and the results were used to estimate the average values of both permeate flux and percent solute rejection. then, these were compared with both experimental data in addition to the results of lumped parameter model. the study showed that distributed parameter model gives better results than lumped parameter one compared with experimental data

A Novel T-Fed 4-Element Quasi-Lumped Resonator Antenna Array

Directory of Open Access Journals (Sweden)

S.S. Olokede

2014-06-01

Full Text Available In this paper, electrically small corporately T-fed quasi-lumped element resonator antenna array is investigated. The radiating element, a quasi-lumped element resonator is excited by a novel semi hybrid ring-like T-shaped corporate feed network. The characteristics losses due to Ohmic and discontinuities along the feed line which invariably constitutes complex feed structures are mitigated at the instance of the proposed antenna. Technique to implement the compact array with the intent to enhance the gain is presented. The operation dynamics of the feed along with its theoretical explanation is also reported. Findings indicates that the measured gain is 10.97 dBi for antenna of an estate area of about 0.677λ_0 × 1.257λ_0 sq. mm. Valuable insight to the optimum design in terms of compactness, good gain, and ease of fabrication is documented.

The welfare gain from replacing the health insurance tax exclusion with lump-sum tax credits.

Science.gov (United States)

Liu, Liqun; Rettenmaier, Andrew J; Saving, Thomas R

2011-06-01

This paper analyzes the welfare gain from replacing the tax exclusion of employer-provided health insurance with a lump-sum tax credit. It differs from earlier studies in that we look at the welfare cost of health insurance tax exclusion as coming directly from excessive health insurance rather than from overconsumption of medical care and that we account for the labor market effect of the tax exclusion on welfare. Both differences work to produce a smaller tax reform welfare gain. For a set of mid-range parameter values, the welfare gain is about 21% of current health insurance tax expenditures. In addition, government tax expenditures would fall by 38%, and health insurance spending would fall by 77% after the reform.

Observational constraints on Hubble parameter in viscous generalized Chaplygin gas

Science.gov (United States)

Thakur, P.

2018-04-01

Cosmological model with viscous generalized Chaplygin gas (in short, VGCG) is considered here to determine observational constraints on its equation of state parameters (in short, EoS) from background data. These data consists of H(z)-z (OHD) data, Baryonic Acoustic Oscillations peak parameter, CMB shift parameter and SN Ia data (Union 2.1). Best-fit values of the EoS parameters including present Hubble parameter (H0) and their acceptable range at different confidence limits are determined. In this model the permitted range for the present Hubble parameter and the transition redshift (zt) at 1σ confidence limits are H0= 70.24^{+0.34}_{-0.36} and zt=0.76^{+0.07}_{-0.07} respectively. These EoS parameters are then compared with those of other models. Present age of the Universe (t0) have also been determined here. Akaike information criterion and Bayesian information criterion for the model selection have been adopted for comparison with other models. It is noted that VGCG model satisfactorily accommodates the present accelerating phase of the Universe.

Spatio-temporal modeling of nonlinear distributed parameter systems

CERN Document Server

Li, Han-Xiong

2011-01-01

The purpose of this volume is to provide a brief review of the previous work on model reduction and identifi cation of distributed parameter systems (DPS), and develop new spatio-temporal models and their relevant identifi cation approaches. In this book, a systematic overview and classifi cation on the modeling of DPS is presented fi rst, which includes model reduction, parameter estimation and system identifi cation. Next, a class of block-oriented nonlinear systems in traditional lumped parameter systems (LPS) is extended to DPS, which results in the spatio-temporal Wiener and Hammerstein s

Advantages and disadvantages of lumping together gastroesophageal reflux disease and dyspepsia

NARCIS (Netherlands)

Smout, André J. P. M.

2006-01-01

PURPOSE OF REVIEW: The aim of this article is to identify and to balance the arguments in favor of and against lumping together gastroesophageal reflux disease and functional dyspepsia. RECENT FINDINGS: In at least half of the patients diagnosed with gastroesophageal reflux disease no organic

Prediction of gasoline yield in a fluid catalytic cracking (FCC riser using k-epsilon turbulence and 4-lump kinetic models: A computational fluid dynamics (CFD approach

Directory of Open Access Journals (Sweden)

Muhammad Ahsan

2015-07-01

Full Text Available Fluid catalytic cracking (FCC is an essential process for the conversion of gas oil to gasoline. This study is an effort to model the phenomenon numerically using commercial computational fluid dynamics (CFD software, heavy density catalyst and 4-lump kinetic model. Geometry, boundary conditions and dimensions of industrial riser for catalytic cracking unit are conferred for 2D simulation using commercial CFD code FLUENT 6.3. Continuity, momentum, energy and species transport equations, applicable to two phase solid and gas flow, are used to simulate the physical phenomenon as efficient as possible. This study implements and predicts the use of the granular Eulerian multiphase model with species transport. Time accurate transient problem is solved with the prediction of mass fraction profiles of gas oil, gasoline, light gas and coke. The output curves demonstrate the breaking of heavy hydrocarbon in the presence of catalyst. An approach proposed in this study shows good agreement with the experimental and numerical data available in the literature.

Comparative study of aspiration and non-aspiration cytology of palpable breast lumps and correlation with histopathology

Directory of Open Access Journals (Sweden)

S Koirala

2014-09-01

Full Text Available Background: Breast lump is one of the most common presentations in surgical outpatient departments with anxiety regarding a possible malignancy. Hence a quick diagnosis of a lump in the breast is essential. Fine needle aspiration cytology is an ideal initial diagnostic modality in breast lumps. There is an alternative method of performing needle aspiration, known as fine needle capillary cytology where the specimen is obtained using just a needle without aspiration.Materials and Methods: This hospital-based cross sectional analytical study was carried out in Department of Pathology in National Academy of Medical Sciences, Bir Hospital for one year. The objective of this study was to compare aspiration and non-aspiration cytology of palpable breast lumps and correlation with histopathology.Results: The five criteria scored for each technique were background blood, amount of cellular material, cellular degeneration, cellular trauma and architectural preservation. Compared to fine needle aspiration cytology, fine needle capillary cytology yields less bloody smears with minimal degenerative changes and offers more diagnostically superior specimens. Fine needle aspiration cytology, on the other hand, gives a good yield of diagnostic material.Conclusion: Fine needle aspiration cytology and fine needle capillary cytology are quick, easy, safe and cost-effective techniques. . A high sensitivity and specificity of cytological diagnosis in this study proves that it is comparable to final histology report in its diagnostic efficiency. Thus, fine needle aspiration cytology is a very important preliminary diagnostic test in palpable breast lumps and the results show a high degree of correlation with the final histopathology report.DOI: http://dx.doi.org/10.3126/jpn.v4i8.11501 Journal of Pathology of Nepal; Vol.4,No. 8 (2014 639-643

New Procedure to Develop Lumped Kinetic Models for Heavy Fuel Oil Combustion

KAUST Repository

Han, Yunqing; Elbaz, Ayman M.; Roberts, William L.; Im, Hong G.

2016-01-01

A new procedure to develop accurate lumped kinetic models for complex fuels is proposed, and applied to the experimental data of the heavy fuel oil measured by thermogravimetry. The new procedure is based on the pseudocomponents representing

Methods of calculating engineering parameters for gas separations

Science.gov (United States)

Lawson, D. D.

1980-01-01

A group additivity method has been generated which makes it possible to estimate, from the structural formulas alone, the energy of vaporization and the molar volume at 25 C of many nonpolar organic liquids. From these two parameters and appropriate thermodynamic relationships it is then possible to predict the vapor pressure of the liquid phase and the solubility of various gases in nonpolar organic liquids. The data are then used to evaluate organic and some inorganic liquids for use in gas separation stages or as heat exchange fluids in prospective thermochemical cycles for hydrogen production.

Sequential Gaussian co-simulation of rate decline parameters of longwall gob gas ventholes

Science.gov (United States)

Karacan, C. Özgen; Olea, Ricardo A.

2013-01-01

Gob gas ventholes (GGVs) are used to control methane inflows into a longwall mining operation by capturing the gas within the overlying fractured strata before it enters the work environment. Using geostatistical co-simulation techniques, this paper maps the parameters of their rate decline behaviors across the study area, a longwall mine in the Northern Appalachian basin. Geostatistical gas-in-place (GIP) simulations were performed, using data from 64 exploration boreholes, and GIP data were mapped within the fractured zone of the study area. In addition, methane flowrates monitored from 10 GGVs were analyzed using decline curve analyses (DCA) techniques to determine parameters of decline rates. Surface elevation showed the most influence on methane production from GGVs and thus was used to investigate its relation with DCA parameters using correlation techniques on normal-scored data. Geostatistical analysis was pursued using sequential Gaussian co-simulation with surface elevation as the secondary variable and with DCA parameters as the primary variables. The primary DCA variables were effective percentage decline rate, rate at production start, rate at the beginning of forecast period, and production end duration. Co-simulation results were presented to visualize decline parameters at an area-wide scale. Wells located at lower elevations, i.e., at the bottom of valleys, tend to perform better in terms of their rate declines compared to those at higher elevations. These results were used to calculate drainage radii of GGVs using GIP realizations. The calculated drainage radii are close to ones predicted by pressure transient tests.

Regionalising Parameters of a Conceptual Rainfall-Runoff Model for ...

African Journals Online (AJOL)

IHACRES, a lumped conceptual rainfall-runoff model, was calibrated to six catchments ranging in size from 49km2 to 600 km2 within the upper Tana River basin to obtain a set of model parameters that characterise the hydrological behaviour within the region. Physical catchment attributes indexing topography, soil and ...

Kinetics parameter measurements on RSG-GAS, a low-enriched fuel reactor

International Nuclear Information System (INIS)

Jujuratisbela, U; Arbie, B; Pinem, S.; Tukiran; Suparlina, L.; Singh, O.P.

1995-01-01

Kinetics parameter measurements, such as reactivity worths of control rods and fuel elements, beam tube void reactivity, power reactivity coefficient and xenon poisoning reactivity have been performed on different cores of Reaktor Serba Guna G.A. Siwabessy (RSG-GAS). In parallel, a programme was also initiated to measure the other kinetics parameters like effective delayed neutron life time, prompt neutron decay constant, validation of period reactivity relationship and zero power frequency response function. The paper provides the results of these measurements. (author)

Primary Breast Tuberculosis Presenting as a Lump: A Rare Modern ...

African Journals Online (AJOL)

A 25‑year‑old female presented with a painless lump in her right breast for 1 month duration. She gave history of low grade fever off and on for the last 2 weeks. There were no other complaints like weight loss, loss of appetite, and any cough. She was unmarried and there was no positive family history of breast tuberculosis.

Impact of meteorological parameters on extracted landfill gas composition and flow

DEFF Research Database (Denmark)

Fathi Aghdam, Ehsan; Scheutz, Charlotte; Kjeldsen, Peter

2018-01-01

The objective of this study was to investigate the impact of four pre-selected meteorological parameters (barometric pressure, wind speed, ambient temperature and solar radiation) on recovered landfill gas (LFG) flow, methane (CH4) content of the LFG and the recovered CH4 flow by performing...

Optimum Design and Operation of Cyclic Storage Systems; Lumped Approach

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Leila Ostadrahimi

2007-01-01

Full Text Available Conjunctive use of surface and groundwater resources is a preferred approach in water resources management. Compared to dam construction, groundwater has certain advantages, among which are less costs, less sedimentation and evaporation, fewer water quality problems, and less social and cultural problems. To reduce the major problems associated with the development of large-scale surface impoundment systems, cyclic storage systems can be used as an alternative. A cyclic storage system (CYCS is an integrated interactive system consisting of two subsystems of surface water storage (reservoir and groundwater; this system together with artificial recharge is able to satisfy the predefined demands with rather high reliability. In order to optimize these systems, one must consider the hydraulic interactions between all the components, but unfortunately it has been neglected in many studies. In this article, a nonlinear optimization model for design and operation of cyclic storage systems has been developed using the lumped approach. In order to evaluate the model, its results have been compared with the results of a model in which distributed approach had been deployed, and so the efficiency of lumped models to solve the problems of cyclic storage systems has been investigated.

Breast Lumps: A 21‑Year Single‑Center Clinical and Histological ...

African Journals Online (AJOL)

Results: Only 38% of the patients came within 3 months of finding lumps in their breast. Onehundred and thirty‑seven patients (83%) had benign disease, i.e., fibroadenoma, mammary dysplasia, cysts, adenomas, tuberculosis, phyllodes tumor, mastitis, and lipoma. Only 16.9% i.e., 28 patients had breast cancer, out of which ...

A weighted least-squares lump correction algorithm for transmission-corrected gamma-ray nondestructive assay

International Nuclear Information System (INIS)

Prettyman, T.H.; Sprinkle, J.K. Jr.; Sheppard, G.A.

1993-01-01

With transmission-corrected gamma-ray nondestructive assay instruments such as the Segmented Gamma Scanner (SGS) and the Tomographic Gamma Scanner (TGS) that is currently under development at Los Alamos National Laboratory, the amount of gamma-ray emitting material can be underestimated for samples in which the emitting material consists of particles or lumps of highly attenuating material. This problem is encountered in the assay of uranium and plutonium-bearing samples. To correct for this source of bias, we have developed a least-squares algorithm that uses transmission-corrected assay results for several emitted energies and a weighting function to account for statistical uncertainties in the assay results. The variation of effective lump size in the fitted model is parameterized; this allows the correction to be performed for a wide range of lump-size distributions. It may be possible to use the reduced chi-squared value obtained in the fit to identify samples in which assay assumptions have been violated. We found that the algorithm significantly reduced bias in simulated assays and improved SGS assay results for plutonium-bearing samples. Further testing will be conducted with the TGS, which is expected to be less susceptible than the SGS to systematic source of bias

A simplified lumped model for the optimization of post-buckled beam architecture wideband generator

Science.gov (United States)

Liu, Weiqun; Formosa, Fabien; Badel, Adrien; Hu, Guangdi

2017-11-01

Buckled beams structures are a classical kind of bistable energy harvesters which attract more and more interests because of their capability to scavenge energy over a large frequency band in comparison with linear generator. The usual modeling approach uses the Galerkin mode discretization method with relatively high complexity, while the simplification with a single-mode solution lacks accuracy. It stems on the optimization of the energy potential features to finally define the physical and geometrical parameters. Therefore, in this paper, a simple lumped model is proposed with explicit relationship between the potential shape and parameters to allow efficient design of bistable beams based generator. The accuracy of the approximation model is studied with the effectiveness of application analyzed. Moreover, an important fact, that the bending stiffness has little influence on the potential shape with low buckling level and the sectional area determined, is found. This feature extends the applicable range of the model by utilizing the design of high moment of inertia. Numerical investigations demonstrate that the proposed model is a simple and reliable tool for design. An optimization example of using the proposed model is demonstrated with satisfactory performance.

Study on Gas Field Optimization Distribution with Parameters Adjustment of the Air Duct Outlet for Mechanized Heading Face in Coal Mine

Science.gov (United States)

Gong, Xiao-Yan; Zhang, Xin-Yi; Wu, Yue; Xia, Zhi-Xin; Li, Ying

2017-12-01

At present, as the increasingly drilling dimensions with cross-section expansion and distance prolong in coal mine, the situation of gas accumulation in mechanized heading face becomes severe. In this paper, optimization research of gas distribution was carried out by adjusting parameters of the air duct outlet, including angle, caliber and the front and rear distance of air duct outlet. Mechanized heading face of Ningtiaota coal mine was taken as the research object, simulated and analyzed the problems of original gas field, the reasonable parameters range of the air duct outlet was determined according to the allowable range of wind speed and the effect of gas dilution, the adjustment range of each parameter of the air duct outlet is preliminarily determined. Base on this, the distribution of gas field under different parameters adjustment of air duct outlet was simulated. The specific parameters under the different distance between the air duct outlet and the mechanized heading face were obtained, and a new method of optimizing the gas distribution by adjusting parameters of the air duct outlet was provided.

Measurements of gas parameters in plasma-assisted supersonic combustion processes using diode laser spectroscopy

International Nuclear Information System (INIS)

Bolshov, Mikhail A; Kuritsyn, Yu A; Liger, V V; Mironenko, V R; Leonov, S B; Yarantsev, D A

2009-01-01

We report a procedure for temperature and water vapour concentration measurements in an unsteady-state combustion zone using diode laser absorption spectroscopy. The procedure involves measurements of the absorption spectrum of water molecules around 1.39 μm. It has been used to determine hydrogen combustion parameters in M = 2 gas flows in the test section of a supersonic wind tunnel. The relatively high intensities of the absorption lines used have enabled direct absorption measurements. We describe a differential technique for measurements of transient absorption spectra, the procedure we used for primary data processing and approaches for determining the gas temperature and H 2 O concentration in the probed zone. The measured absorption spectra are fitted with spectra simulated using parameters from spectroscopic databases. The combustion-time-averaged (∼50 ms) gas temperature and water vapour partial pressure in the hot wake region are determined to be 1050 K and 21 Torr, respectively. The large signal-to-noise ratio in our measurements allowed us to assess the temporal behaviour of these parameters. The accuracy in our temperature measurements in the probed zone is ∼40 K. (laser applications and other topics in quantum electronics)

Effects of non-LTE multiplet dynamics on lumped-state modelling in moderate to high atomic number plasmas

International Nuclear Information System (INIS)

Whitney, K G; Dasgupta, A; Davis, J; Coverdale, C A

2007-01-01

Two atomic models of the population dynamics of substates within the n 4 and n = 3 multiplets of nickel-like tungsten and beryllium-like iron, respectively, are described in this paper. The flexible atomic code (FAC) is used to calculate the collisional and radiative couplings and energy levels of the excited states within these ionization stages. These atomic models are then placed within larger principal-quantum-number-based ionization dynamic models of both tungsten and iron plasmas. Collisional-radiative equilibrium calculations are then carried out using these models that demonstrate how the multiplet substates depart from local thermodynamic equilibrium (LTE) as a function of ion density. The effect of these deviations from LTE on the radiative and collisional deexcitation rates of lumped 3s, 3p, 3d, 4s, 4p, 4d and 4f states is then calculated and least-squares fits to the density dependence of these lumped-state rate coefficients are obtained. The calculations show that, with the use of lumped-state models (which are in common use), one can accurately model the L- and M-shell ionization dynamics occurring in present-day Z-pinch experiments only through the addition of these extra, non-LTE-induced, rate coefficient density dependences. However, the derivation and use of low-order polynomial fits to these density dependences makes lumped-state modelling both viable and of value for post-processing analyses

Long-term gas migration modelling in compacted bentonite using swelling/shrinkage-dependent two phase flow parameters

International Nuclear Information System (INIS)

Tawara, Y.; Mori, K.; Tada, K.; Shimura, T.; Sato, S.; Yamamoto, S.; Asano, H.; Namiki, K.

2012-01-01

Document available in extended abstract form only. After the completion of field-scaled Gas Migration Test (GMT) at the Grimsel Test Site (GTS Phase V Project, 1996-2004), an advanced gas migration modelling study has been implemented to increase the accuracy and reliability as a part of the R and D programs by the Radioactive Waste Management funding and research Center (RWMC) in Japan. The multiple gas migration modes which consist of diffusive transport of dissolved gas, conventional two phase flow, pore failure induced microscopic fissuring and macroscopic fracturing flow, were identified in GMT bentonite. However the required parameters and constitutive models governing those modes are still uncertain. To tackle this issue, an extended validation and scoping study aiming to generalize such gas migration behavior has been performed in the advanced gas migration modelling study. One of the main objectives of the validation study is to identify gas migration modes using laboratory test data and to qualify the alternative models and parameters. In the scoping study, we have extracted the specific THMC (Thermal, Hydrological, Mechanical and Chemical) coupled processes which have impacts on the performance measures such as the pressure built-up in EBS (Engineered Barrier System) and expelled water to the geosphere by gas generation and transport. The measured data of hydration tests and gas injection tests using bentonite specimens with different water contents were reproduced. Two phase flow parameters were estimated using the observed data of both types of tests, independently. The simulated results of the conventional two phase flow model were well-matched with the hydration test data. In the gas injection test, the extended two phase flow model which simulates the pressure-induced pore failure (pathway dilation), was able to reproduce observed data reasonably. However, we found that the identified parameters obtained from the hydration test data were

Gas ultracentrifuge separative parameters modeling using hybrid neural networks

International Nuclear Information System (INIS)

Crus, Maria Ursulina de Lima

2005-01-01

A hybrid neural network is developed for the calculation of the separative performance of an ultracentrifuge. A feed forward neural network is trained to estimate the internal flow parameters of a gas ultracentrifuge, and then these parameters are applied in the diffusion equation. For this study, a 573 experimental data set is used to establish the relation between the separative performance and the controlled variables. The process control variables considered are: the feed flow rate F, the cut θ and the product pressure Pp. The mechanical arrangements consider the radial waste scoop dimension, the rotating baffle size D s and the axial feed location Z E . The methodology was validated through the comparison of the calculated separative performance with experimental values. This methodology may be applied to other processes, just by adapting the phenomenological procedures. (author)

Painless lump over the forehead which turned painful: an unusual presentation of hepatocellular carcinoma

Directory of Open Access Journals (Sweden)

S P Susheela

2015-05-01

Full Text Available Hepatocellular carcinoma (HCC is one of the most common malignancies and is known to most often present with symptomatology pertaining to local hepatic disease. Although HCC is known to metastasize to lungs, abdominal lymph nodes, adrenal glands and the vertebral column, it is rather rare to come across patients with skull metastasis. The manifestation of a solitary frontal bone metastasis leading to a painless lump over the forehead as the initial presenting feature of HCC is highly unusual. This case report pertains to a 40-year-old male patient who had initially observed a painless lump over his forehead that was gradually increasing in size over a span of 3 months. He sought medical attention when, after several months, the "painless lump" suddenly became painful. Investigations revealed the involvement of both the outer and the inner table of the frontal bone, and a biopsy revealed the histopathology to be that of HCC. On further investigation, he was found to have systemic disseminated disease involving both the left and right lungs and vertebrae and treatment was initiated with sorafenib. Despite an initial partial response, the patient subsequently succumbed to hepatic failure. This case report illustrates the fact that HCC can silently progress, and even lead to dissemination and distant metastases before becoming clinically evident.

ANALISIS PENGARUH DENSITAS BAHAN BAKAR SILISIDA TERHADAP PARAMETER KINETIK TERAS REAKTOR RSG-GAS

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Tukiran s

2016-11-01

Full Text Available Saat ini RSG-GAS menggunakan elemen bakar silisida 2,96 g U/cc. Untuk meningkatkan waktu operasi reaktor maka akan direncanakan untuk mengganti elemen bakar silisida dengan kerapatan yang lebih tinggi. Keuntungan reaktor dengan bahan bakar kerapatan tinggi adalah dapat lebih efektif dan efisien. Maka perlu dilakukan perhitungan parameter kinetik teras silisida kerapatan tinggi mengingat pengaruhnya sangat penting untuk keselamatan operasi reaktor. Parameter kinetik yang dihitung yaitu fraksi neutron kasip efektif, konstanta peluruhan neutron kasip, umur neutron serempak yang merupakan faktor utama dalam kontrol dan keselamatan. Bahan bakar silisida tipe pelat dengan densitas 2,96 - 4,8 gU/cm3 digunakan pada teras RSG-GAS untuk menganalisis perhitungan parameter kinetik. Perhitungan sel dilakukan dengan paket program WIMSD-5B dan paket program Batan-2DIFF digunakan untuk perhitungan teras. Hasil perhitungan menunjukkan bahwa harga fraksi neutron kasip turun dengan naiknya densitas bahan bakar. Turunnya nilai parameter kinetik ini tidak mengganggu pergantian bahan bakar ke densitas yang lebih tinggi. Turunnya nilai parameter kinetik rata-rata dari densitas 2,96 gU/cm3 ke 3,55 gU/cm3 adalah 1,3 % sedangkan dari densitas 2,96 gU/cm3 ke 4,8 gU/cm3 adalah 2,2 % . Sehingga jika dilakukan pergantian bahan bakar maka ditinjau dari segi neutronik dan parameter kinetiknya tidak akan mengalami perubahan dalam pola operasi reaktor atau manajemen bahan bakar dan tidak akan berpengaruh terhadap keselamatan operasi reaktor.

Assessing aquifer vulnerability from lumped parameter modeling of modern water proportions in groundwater mixtures - Application to nitrate pollution in California's South Coast Range

Science.gov (United States)

Hagedorn, B.; Ruane, M.; Clark, N.

2017-12-01

In California, the overuse of synthetic fertilizers and manure in agriculture have caused nitrate (NO3) to be one of the state's most widespread groundwater pollutants. Given that nitrogen fertilizer applications have steadily increased since the 1950s and given that soil percolation and recharge transit times in California can exceed timescales of decades, the nitrate impact on groundwater resources is likely a legacy for years and even decades to come. This study presents a methodology for groundwater vulnerability assessment that operates independently of difficult-to-constrain soil and aquifer property data (i.e., saturated thickness, texture, porosity, conductivity, etc.), but rather utilizes groundwater age and, more importantly, groundwater mixing information to illustrate actual vulnerability at the water table. To accomplish this, the modern (i.e., less than 60-year old) water proportion (MWP) in groundwater mixtures is computed via lumped parameter modeling of chemical tracer (i.e., 3H, 14C and 3Hetrit) data. These MWPs are then linked to groundwater dissolved oxygen (DO) values to describe the risk for soil zone-derived nitrate to accumulate in the saturated zone. Preliminary studies carried out for 71 wells in California's South Coast Range-Coastal (SCRC) study unit reveal MWP values derived from binary dispersion models of 3.24% to 21.8%. The fact that high MWPs generally coincide with oxic (DO ≥1.5 mg/L) groundwater conditions underscores the risk towards increased groundwater NO3 pollution for many of the tested wells. These results support the conclusion that best agricultural management and policy objectives should incorporate groundwater vulnerability models that are developed at the same spatial scale as the decision making.

Systematic reduction of complex tropospheric chemical mechanisms, Part II: Lumping using a time-scale based approach

Directory of Open Access Journals (Sweden)

L. E. Whitehouse

2004-01-01

Full Text Available This paper presents a formal method of species lumping that can be applied automatically to intermediate compounds within detailed and complex tropospheric chemical reaction schemes. The method is based on grouping species with reference to their chemical lifetimes and reactivity structures. A method for determining the forward and reverse transformations between individual and lumped compounds is developed. Preliminary application to the Leeds Master Chemical Mechanism (MCMv2.0 has led to the removal of 734 species and 1777 reactions from the scheme, with minimal degradation of accuracy across a wide range of test trajectories relevant to polluted tropospheric conditions. The lumped groups are seen to relate to groups of peroxy acyl nitrates, nitrates, carbonates, oxepins, substituted phenols, oxeacids and peracids with similar lifetimes and reaction rates with OH. In combination with other reduction techniques, such as sensitivity analysis and the application of the quasi-steady state approximation (QSSA, a reduced mechanism has been developed that contains 35% of the number of species and 40% of the number of reactions compared to the full mechanism. This has led to a speed up of a factor of 8 in terms of computer calculation time within box model simulations.

Numerical analysis of macro-crack formation behavior within the lump coke; Cokes sonai kiretsu shinten kiko no kaiseki

Energy Technology Data Exchange (ETDEWEB)

Aoki, H; Sato, H; Miura, T [Tohoku University, Sendai (Japan). Faculty of Engineering

1995-03-15

The thermal stress analysis within lump coke was studied in order to investigate macro-crack formation and deformation behavior which strongly influence heat and mass transfer in a coke oven chamber. The dilatation of plastic layer, heating rate dependence of thermophysical and mechanical properties of coal/coke, creep in the plastic and semi-coke layers, macro-crack propagation and radiative heat transfer within the macro-crack were considered in an analytical model. The macro-crack propagation was determined from the estimated crack tip stress intensity factor, K{sub I}, at the macro-crack tip compared with the plane strain fracture toughness, K{sub IC}, through the unsteady-state calculation. Calculated results on crack formation and deformation behavior of lump coke were in good agreement with experimental observations in a laboratory-scale oven chamber. The analytical model could predict micro-crack formation within the lump coke normal to the heated wall and the coke surface close to the heated wall. 12 refs., 13 figs.

The lumped heat capacity method applied to target heating

OpenAIRE

Rickards, J.

2013-01-01

The temperature of metal samples was measured while they were bombarded by the beam from the a particle accelerator. The evolution of the temperature with time can be explained using the lumped heat capacity method of heat transfer. A strong dependence on the type of mounting was found. Se midió la temperatura de muestras metálicas al ser bombardeadas por el haz de iones del Acelerador Pelletron del Instituto de Física. La evolución de la temperatura con el tiempo se puede explicar usando ...

Probing lumps of wee partons in deep inelastic scattering

International Nuclear Information System (INIS)

Buchmueller, W.

1994-06-01

Recently, the ZEUS collaboration has reported on several remarkable properties of events with a large rapidity gap in deep inelastic scattering. We suggest that the mechanism underlying these events is the scattering of electrons off lumps of wee partons inside the proton. Based on an effective lagrangian approach the Q 2 -, x- and W-distributions are evaluated. For sufficiently small invariant mass of the detected hadronic system, the mechanism implies leading twist behaviour. The x- and W-distributions are determined by the Lipatov exponent which governs the behaviour of parton densities at small x. (orig.)

New equivalent lumped electrical circuit for piezoelectric transformers.

Science.gov (United States)

Gonnard, Paul; Schmitt, P M; Brissaud, Michel

2006-04-01

A new equivalent circuit is proposed for a contour-vibration-mode piezoelectric transformer (PT). It is shown that the usual lumped equivalent circuit derived from the conventional Mason approach is not accurate. The proposed circuit, built on experimental measurements, makes an explicit difference between the elastic energies stored respectively on the primary and secondary parts. The experimental and theoretical resonance frequencies with the secondary in open or short circuit are in good agreement as well as the output "voltage-current" characteristic and the optimum efficiency working point. This circuit can be extended to various PT configurations and appears to be a useful tool for modeling electronic devices that integrate piezoelectric transformers.

Acute lymphoblastic leukemia presenting as a breast lump: A report of two cases

Directory of Open Access Journals (Sweden)

Syed Besina

2013-01-01

Full Text Available Extra-medullary leukemic infiltration of the breast by acute lymphoblastic leukemia (ALL is very rare. We report two cases of ALL presenting as breast masses and diagnosed on fine-needle aspiration (FNA. Our first patient, a post-partum 30-year-old female, developed bilateral breast lumps in her last trimester of pregnancy and complained of easy fatigability. Our second patient, a 14-year-old girl, presented with a right-breast lump of 1-week duration. She had received treatment for ALL 1 year back and had been in complete remission for the last 1 year. FNA of the breast nodules done in both the cases revealed diffuse infiltration by lymphoblasts. Subsequent hematological investigations confirmed bone marrow involvement by ALL in the first case and extra-medullary relapse in the second case. Fine-needle aspiration cytology (FNAC is an easy and cost effective method for the early diagnosis of metastatic leukemic infiltration, avoiding unnecessary excisional biopsies in such cases.

Some error estimates for the lumped mass finite element method for a parabolic problem

KAUST Repository

Chatzipantelidis, P.; Lazarov, R. D.; Thomé e, V.

2012-01-01

for the standard Galerkin method carry over to the lumped mass method whereas nonsmooth initial data estimates require special assumptions on the triangulation. We also discuss the application to time discretization by the backward Euler and Crank-Nicolson methods

Simulations of hydrogen distribution experiments using the PRESCON2 and GOTHIC codes

International Nuclear Information System (INIS)

Nguyen, T.H.; Collins, W.M.

1994-01-01

The main objective of this work is to develop modelling guidelines in the use of containment models to more accurately predict hydrogen distribution in the HDR facility and to assess the ability of both lumped and distributed parameter models in predicting natural convective flows within containment. Experiences learned from this exercise will be applied to present methodologies used in licensing analyses for CANDU containments. PRESCON2 simulations of hydrogen distribution experiments performed in the HDR facility show hydrogen and helium concentrations are under-predicted at high elevations and over predicted at low elevations. Acceptable predictions of the gas concentration are obtained in the vicinity of the release. Results obtained from GOTHIC simulations using lumped parameter models are very comparable to those predicted by PRESCON2. This indicates that lumped parameter codes tend to over-estimate the degree of mixing of fluids due to the inherent nodal atmospheric homogeneity assumption in their numerical formulation. Results obtained from the GOTHIC simulation using a simple distributed parameter model show little improvement compared to those predicted using the lumped parameter model. This indicates that a simple 3-D model will not be sufficient to make significant improvements in the results. More detailed modelling of the junction flows and finer grids should lead to more accurate results. More detailed investigations employing finer 3-D meshes is under investigation. (author)

Seismo-Geochemical Variations in SW Taiwan: Multi-Parameter Automatic Gas Monitoring Results

Science.gov (United States)

Yang, T. F.; Fu, C.-C.; Walia, V.; Chen, C.-H.; Chyi, L. L.; Liu, T.-K.; Song, S.-R.; Lee, M.; Lin, C.-W.; Lin, C.-C.

2006-04-01

Gas variations of many mud volcanoes and hot springs distributed along the tectonic sutures in southwestern Taiwan are considered to be sensitive to the earthquake activity. Therefore, a multi-parameter automatic gas station was built on the bank of one of the largest mud-pools at an active fault zone of southwestern Taiwan, for continuous monitoring of CO2, CH4, N2 and H2O, the major constituents of its bubbling gases. During the year round monitoring from October 2001 to October 2002, the gas composition, especially, CH4 and CO2, of the mud pool showed significant variations. Taking the CO2/CH4 ratio as the main indicator, anomalous variations can be recognized from a few days to a few weeks before earthquakes and correlated well with those with a local magnitude >4.0 and local intensities >2. It is concluded that the gas composition in the area is sensitive to the local crustal stress/strain and is worthy to conduct real-time monitoring for the seismo-geochemical precursors.

Sensitivity studies on parameters affecting gas release from an underground rock cavern

International Nuclear Information System (INIS)

Schlueter, E.; Pruess, K.

1990-01-01

A series of numerical simulation experiments is performed to quantify the effects of the release and migration of non-condensible gas in water-saturated fractured rock formations. The relative importance of multiphase parameters such as relative permeability, capillary pressure, intrinsic permeability, and porosity on system behavior is studied. 10 refs., 28 figs., 5 tabs

Gas exchange and chlorophyll a fluorescence parameters of ornamental bromeliads

Directory of Open Access Journals (Sweden)

Karina Gonçalves da Silva

2017-10-01

Full Text Available Gas exchange and chlorophyll a fluorescence are widely used in physiological and ecological studies; however, few studies have used these techniques with ornamental plants. This study tested the potential contribution of gas exchange and chlorophyll a fluorescence to evaluate the water and nutrients uptake by the tank and root system of epiphyte bromeliad Guzmania lingulata. For this purpose, we conducted an experiment with different water regime and another with different concentrations of nitrogen. The experiments were: 1 - Watering: Control (application of water into Tank and Root, Tank (watering into Tank, Root (watering Root and Drought (water suspension during the 90 days of experimentation and 2 - Nitrogen: Plants fertilized with Hoagland and Arnon nutrient solution exclusively into Tank or Root with nitrogen concentrations of control and 2.62 or 5.34 mM N applied as urea. The Fv /Fm ratio allowed comparing the treatments between experiments, demonstrating that Root and Tank both have the capacity to maintain G. lingulata photosynthetic activity and growth, while Drought treatment (water suspension was the limiting factor for energy conversion efficiency of PSII. However, gas exchange was more permissive as a parameter for comparing treatments in the nitrogen experiment, providing important information about the general aspects of the photosynthetic process in the watering experiment. Both gas exchange and chlorophyll a fluorescence can support the evaluation of G. lingulata physiological status and can be useful tools in ornamental horticultural studies.

Path lumping: An efficient algorithm to identify metastable path channels for conformational dynamics of multi-body systems

Science.gov (United States)

Meng, Luming; Sheong, Fu Kit; Zeng, Xiangze; Zhu, Lizhe; Huang, Xuhui

2017-07-01

Constructing Markov state models from large-scale molecular dynamics simulation trajectories is a promising approach to dissect the kinetic mechanisms of complex chemical and biological processes. Combined with transition path theory, Markov state models can be applied to identify all pathways connecting any conformational states of interest. However, the identified pathways can be too complex to comprehend, especially for multi-body processes where numerous parallel pathways with comparable flux probability often coexist. Here, we have developed a path lumping method to group these parallel pathways into metastable path channels for analysis. We define the similarity between two pathways as the intercrossing flux between them and then apply the spectral clustering algorithm to lump these pathways into groups. We demonstrate the power of our method by applying it to two systems: a 2D-potential consisting of four metastable energy channels and the hydrophobic collapse process of two hydrophobic molecules. In both cases, our algorithm successfully reveals the metastable path channels. We expect this path lumping algorithm to be a promising tool for revealing unprecedented insights into the kinetic mechanisms of complex multi-body processes.

Energy-state formulation of lumped volume dynamic equations with application to a simplified free piston Stirling engine

Science.gov (United States)

Daniele, C. J.; Lorenzo, C. F.

1979-01-01

Lumped volume dynamic equations are derived using an energy-state formulation. This technique requires that kinetic and potential energy state functions be written for the physical system being investigated. To account for losses in the system, a Rayleigh dissipation function is also formed. Using these functions, a Lagrangian is formed and using Lagrange's equation, the equations of motion for the system are derived. The results of the application of this technique to a lumped volume are used to derive a model for the free-piston Stirling engine. The model was simplified and programmed on an analog computer. Results are given comparing the model response with experimental data.

A Size Reduction Technique for Mobile Phone PIFA Antennas Using Lumped Inductors

DEFF Research Database (Denmark)

Thaysen, Jesper; Jakobsen, Kaj Bjarne

2005-01-01

A size reduction technique for the planar inverted-F antenna (PIFA) is presented. An 18 nH lumped inductor is used in addition to a small 0.3 cm3 PIFA. The PIFA is located on dielectric foam, 5 mm above a 40 mm × 100 mm ground plane. It is possible to reduce the center frequency (|S11|min) by 33 ...

Parameter identification in a nonlinear nuclear reactor model using quasilinearization

International Nuclear Information System (INIS)

Barreto, J.M.; Martins Neto, A.F.; Tanomaru, N.

1980-09-01

Parameter identification in a nonlinear, lumped parameter, nuclear reactor model is carried out using discrete output power measurements during the transient caused by an external reactivity change. In order to minimize the difference between the model and the reactor power responses, the parameter promt neutron generation time and a parameter in fuel temperature reactivity coefficient equation are adjusted using quasilinearization. The influences of the external reactivity disturbance, the number and frequency of measurements and the measurement noise level on the method accuracy and rate of convergence are analysed through simulation. Procedures for the design of the identification experiments are suggested. The method proved to be very effective for low level noise measurements. (Author) [pt

Influence of source parameters on the growth of metal nanoparticles by sputter-gas-aggregation

Science.gov (United States)

Khojasteh, Malak; Kresin, Vitaly V.

2017-11-01

We describe the production of size-selected manganese nanoclusters using a magnetron sputtering/aggregation source. Since nanoparticle production is sensitive to a range of overlapping operating parameters (in particular, the sputtering discharge power, the inert gas flow rates, and the aggregation length), we focus on a detailed map of the influence of each parameter on the average nanocluster size. In this way, it is possible to identify the main contribution of each parameter to the physical processes taking place within the source. The discharge power and argon flow supply the metal vapor, and argon also plays a crucial role in the formation of condensation nuclei via three-body collisions. However, the argon flow and the discharge power have a relatively weak effect on the average nanocluster size in the exiting beam. Here the defining role is played by the source residence time, governed by the helium supply (which raises the pressure and density of the gas column inside the source, resulting in more efficient transport of nanoparticles to the exit) and by the aggregation path length.

The complete information for phenomenal distributed parameter control of multicomponent chemical processes in gas, fluid and solid phase

International Nuclear Information System (INIS)

Niemiec, W.

1985-01-01

A constitutive mathematical model of distributed parameters of multicomponent chemical processes in gas, fluid and solid phase is utilized to the realization of phenomenal distributed parameter control of these processes. Original systems of partial differential constitutive state equations, in the following derivative forms /I/, /II/ and /III/ are solved in this paper from the point of view of information for phenomenal distributed parameter control of considered processes. Obtained in this way for multicomponent chemical processes in gas, fluid and solid phase: -dynamical working space-time characteristics/analytical solutions in working space-time of chemical reactors/, -dynamical phenomenal Green functions as working space-time transfer functions, -statical working space characteristics /analytical solutions in working space of chemical reactors/, -statical phenomenal Green functions as working space transfer functions, are applied, as information for realization of constitutive distributed parameter control of mass, energy and momentum aspects of above processes. Two cases are considered by existence of: A/sup o/ - initial conditions, B/sup o/ - initial and boundary conditions, for multicomponent chemical processes in gas, fluid and solid phase

Novo modelo de parâmetros concentrados aplicado à hidratação de grãos New model of lumped parameters applied to grain hydration

Directory of Open Access Journals (Sweden)

Mônica Ronobo Coutinho

2007-09-01

Full Text Available Este trabalho apresenta um novo modelo fenomenológico de parâmetros concentrados para a hidratação de grãos de soja, obtido a partir de um balanço de massa em regime transiente nos grãos, admitindo duas hipóteses básicas: 1º variação do volume do grão diretamente proporcional à variação da sua massa ao longo da hidratação; e 2º variação exponencial do coeficiente de transferência de massa aparente em função da concentração de água na soja. Este modelo possui apenas dois parâmetros, os quais foram estimados a partir do ajuste deste às medidas da umidade do grão ao longo do tempo, avaliadas em várias temperaturas. Os resultados revelam que o modelo proposto é adequado, enquanto o coeficiente de transferência de massa aparente depende da temperatura e apresenta variações significativas ao longo da hidratação.A new first principle model with lumped parameters was developed for the hydration of soya beans. A transient mass balance was applied to the soya beans taking into consideration two basic hypotheses:1º variation of the volume directly proportional to the variation of the mass of the grain during the process, 2º Exponential variation of the apparent coefficient of mass transfer in function of water concentration in the soy. This model has got just two parameters, which were evaluated from adjustment of model to the measures of grain moisture along the time, at several temperatures. The results indicate that the proposed model was able to represent the hydration process, while the mass transfer coefficient depends on the temperature and it presents significant variations along the hydration.

Generalized Kutta–Joukowski theorem for multi-vortex and multi-airfoil flow (a lumped vortex model

Directory of Open Access Journals (Sweden)

Bai Chenyuan

2014-02-01

Full Text Available For purpose of easy identification of the role of free vortices on the lift and drag and for purpose of fast or engineering evaluation of forces for each individual body, we will extend in this paper the Kutta–Joukowski (KJ theorem to the case of inviscid flow with multiple free vortices and multiple airfoils. The major simplification used in this paper is that each airfoil is represented by a lumped vortex, which may hold true when the distances between vortices and bodies are large enough. It is found that the Kutta–Joukowski theorem still holds provided that the local freestream velocity and the circulation of the bound vortex are modified by the induced velocity due to the outside vortices and airfoils. We will demonstrate how to use the present result to identify the role of vortices on the forces according to their position, strength and rotation direction. Moreover, we will apply the present results to a two-cylinder example of Crowdy and the Wagner example to demonstrate how to perform fast force approximation for multi-body and multi-vortex problems. The lumped vortex assumption has the advantage of giving such kinds of approximate results which are very easy to use. The lack of accuracy for such a fast evaluation will be compensated by a rigorous extension, with the lumped vortex assumption removed and with vortex production included, in a forthcoming paper.

Improving the temporal transposability of lumped hydrological models on twenty diversified U.S. watersheds

Directory of Open Access Journals (Sweden)

G. Seiller

2015-03-01

Full Text Available Study region: Twenty diversified U.S. watersheds. Study focus: Identifying optimal parameter sets for hydrological modeling on a specific catchment remains an important challenge for numerous applied and research projects. This is particularly the case when working under contrasted climate conditions that question the temporal transposability of the parameters. Methodologies exist, mainly based on Differential Split Sample Tests, to examine this concern. This work assesses the improved temporal transposability of a multimodel implementation, based on twenty dissimilar lumped conceptual structures and on twenty U.S. watersheds, over the performance of the individual models. New hydrological insights for the region: Individual and collective temporal transposabilities are analyzed and compared on the twenty studied watersheds. Results show that individual models performances on contrasted climate conditions are very dissimilar depending on test period and watershed, without the possibility to identify a best solution in all circumstances. They also confirm that performance and robustness are clearly enhanced using an ensemble of rainfall-runoff models instead of individual ones. The use of (calibrated weight averaged multimodels further improves temporal transposability over simple averaged ensemble, in most instances, confirming added-value of this approach but also the need to evaluate how individual models compensate each other errors. Keywords: Rainfall-runoff modeling, Multimodel approach, Differential Split Sample Test, Deterministic combination, Outputs averaging

Application of Biologically-Based Lumping To Investigate the Toxicological Interactions of a Complex Gasoline Mixture

Science.gov (United States)

People are often exposed to complex mixtures of environmental chemicals such as gasoline, tobacco smoke, water contaminants, or food additives. However, investigators have often considered complex mixtures as one lumped entity. Valuable information can be obtained from these exp...

A fatigue initiation parameter for gas pipe steel submitted to hydrogen absorption

Energy Technology Data Exchange (ETDEWEB)

Capelle, J; Gilgert, J; Pluvinage, G [LaBPS - Ecole Nationale d' Ingenieurs de Metz et Universite Paul Verlaine Metz, Ile du Saulcy, 57045 Metz (France)

2010-01-15

Fatigue initiation resistance has been determined on API 5L X52 gas pipe steel. Tests have been performed on Roman Tile (RT) specimen and fatigue initiation was detected by acoustic emission. A comparison between specimens electrolytically charged with hydrogen and specimens without hydrogen absorption were made and it has been noted that fatigue initiation time is reduced of about 3 times when hydrogen embrittlement occurs. It has been proposed to use the concept of Notch Stress Intensity Factor as parameter to describe the fatigue initiation process. Due to the fact that hydrogen is localised in area with high hydrostatic pressure, definitions of local effective stress and distance have been modified when hydrogen is absorbed. This modification can be explained by existence of a ductile-brittle transition with hydrogen concentration. The fatigue initiation resistance curve allows that to determine a threshold for large number of cycles of fatigue non initiation. This parameter introduced in a Failure Assessment Diagram (FAD) provides supplementary information about defect nocivity in gas pipes: a non-critical defect can be detected as dormant or not dormant defect i.e., as non propagating defect. (author)

[Effects of different water potentials on leaf gas exchange and chlorophyll fluorescence parameters of cucumber during post-flowering growth stage].

Science.gov (United States)

Lin, Lu; Tang, Yun; Zhang, Ji-tao; Yan, Wan-li; Xiao, Jian-hong; Ding, Chao; Dong, Chuan; Ji, Zeng-shun

2015-07-01

Impacts of different substrate water potentials (SWP) on leaf gas exchange and chlorophyll fluorescence parameters of greenhouse cucumber during its post-flowering growth stage were analyzed in this study. The results demonstrated that -10 and -30 kPa were the critical values for initiating stomatal and non-stomatal limitation of drought stress, respectively. During the stage of no drought stress (-10 kPa gas exchange parameters and chlorophyll fluorescence parameters were not different significantly among treatments. During the stage of stomatal limitation of drought stress (-30 kPawater use efficiency (WUEi) and non-photochemical quenching (qN) increased. In this stage, gas exchange parameters changed faster than chlorophyll fluorescence parameters and differed significantly among treatments. During the stage of non-stomatal limitation of drought stress (-45 kPa≤SWP ≤ -30 kPa), with the decrease of SWP, light saturation point (LSP), Rd, CE, Vcmax, VTPU, LS, WUEi, ΦpPSII, Fv/Fm and qp decreased, while CCP, Ci and qN increased. In this stage, chlorophyll fluorescence parameters changed faster than gas exchange parameters and differed significantly among treatments. In production of greenhouse cucumber, -10 and -5 kPa should be the lower and upper limit value of irrigation, respectively. The stomatal limitation of drought stress could be relieved by irrigation before SWP decreased to -30 kPa. While, the non-stomatal injury of drought stress would be unrecoverable once SWP decreased to lower than -30 kPa.

Lumped model for rotational modes in phononic crystals

KAUST Repository

Peng, Pai

2012-10-16

We present a lumped model for the rotational modes induced by the rotational motion of individual scatterers in two-dimensional phononic crystals comprised of square arrays of solid cylindrical scatterers in solid hosts. The model provides a physical interpretation of the origin of the rotational modes, reveals the important role played by the rotational motion in determining the band structure, and reproduces the dispersion relations in a certain range. The model increases the possibilities of manipulating wave propagation in phononic crystals. In particular, expressions derived from the model for eigenfrequencies at high symmetry points unambiguously predict the presence of a new type of Dirac-like cone at the Brillouin center, which is found to be the result of accidental degeneracy of the rotational and dipolar modes.

Lumped model for rotational modes in phononic crystals

KAUST Repository

Peng, Pai; Mei, Jun; Wu, Ying

2012-01-01

We present a lumped model for the rotational modes induced by the rotational motion of individual scatterers in two-dimensional phononic crystals comprised of square arrays of solid cylindrical scatterers in solid hosts. The model provides a physical interpretation of the origin of the rotational modes, reveals the important role played by the rotational motion in determining the band structure, and reproduces the dispersion relations in a certain range. The model increases the possibilities of manipulating wave propagation in phononic crystals. In particular, expressions derived from the model for eigenfrequencies at high symmetry points unambiguously predict the presence of a new type of Dirac-like cone at the Brillouin center, which is found to be the result of accidental degeneracy of the rotational and dipolar modes.

The influence of lumping on the behavior of reservoir with light oil and CO2

Energy Technology Data Exchange (ETDEWEB)

Scanavini, Helena Finardi Alvares [Universidade Estadual de Campinas (UNISIM/UNICAMP), SP (Brazil). Dept. de Engenharia de Petroleo. Pesquisa em Simulacao e Gerenciamento de Reservatorios; Schiozer, Denis Jose [Universidade Estadual de Campinas (DEP/FEM/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Engenharia de Petroleo

2012-07-01

Compositional simulation demands a large number of equations and functions to be solved, once fluid properties depend on reservoir pressure and temperature and also on fluid composition. As a consequence, the number of components used influences considerably in the simulation run time and accuracy: more components yield more equations to be solved with expected higher run time. Giant petroleum fields discovered recently in Brazil (pre-salt reservoirs) demand compositional simulation due to the fluid characteristics (light oil with the presence of CO2). However, the computational time can be a limitation because of the number of grid blocks that are necessary to represent the reservoir. So, reducing the number of components is an important step for the simulation models. Under this context, this paper presents a study on the influence of different lumping clusters, used to reduce the number of components in a volatile oil, on reservoir simulation. Phase diagram, saturation pressure and simulation results were used for comparison purposes. The best results were obtained for the cases with 14, 9 and 7 pseudo components, which represented correctly the original fluid, reducing till three times the simulation run time, for the same production volumes of oil and gas. (author)

20 CFR 222.31 - Relationship as child for annuity and lump-sum payment purposes.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Relationship as child for annuity and lump... UNDER THE RAILROAD RETIREMENT ACT FAMILY RELATIONSHIPS Relationship as Child § 222.31 Relationship as... the employee. For procedures on how a determination of the person's relationship to the employee is...

Experimental Analyses of the Major Parameters Affecting the Intensity of Outbursts of Coal and Gas

Science.gov (United States)

Nie, W.; Peng, S. J.; Xu, J.; Liu, L. R.; Wang, G.; Geng, J. B.

2014-01-01

With an increase in mining depth and production, the intensity and frequency of outburst of coal and gas have a tendency to increase. Estimating the intensity of outbursts of coal and gas plays an important role because of its relation with the risk value. In this paper, we described the semiquantitative relations between major parameters and intensity of outburst based on physical experiments. The results showed increment of geostress simulated by horizontal load (from 1.4, 2.4, 3.2, to 3.4 MPa) or vertical load (from 2, 3, 3.6, to 4 MPa) improved the relative intensity rate (3.763–7.403% and 1.273–7.99%); the increment of porosity (from 1.57, 2.51, 3, to 3.6%) improved the relative intensity rate from 3.8 to 13.8%; the increment of gas pressure (from 0, 0.5, 0.65, 0.72, 1, to 1.5 Mpa) induced the relative intensity rate to decrease from 38.22 to 0%; the increment of water content (from 0, 2, 4, to 8%) caused the relative intensity rate to drop from 5.425 to 0.5%. Furthermore, sensitivity and range analysis evaluates coupled factors affecting the relative intensity. In addition, the distinction with initiation of outburst of coal and gas affected by these parameters is discussed by the relative threshold of gas content rate. PMID:25162042

Drop-on-Demand Inkjet Printhead Performance Enhancement by Dynamic Lumped Element Modeling for Printable Electronics Fabrication

Directory of Open Access Journals (Sweden)

Maowei He

2014-01-01

Full Text Available The major challenge in printable electronics fabrication is the print resolution and accuracy. In this paper, the dynamic lumped element model (DLEM is proposed to directly simulate an inkjet-printed nanosilver droplet formation process and used for predictively controlling jetting characteristics. The static lumped element model (LEM previously developed by the authors is extended to dynamic model with time-varying equivalent circuits to characterize nonlinear behaviors of piezoelectric printhead. The model is then used to investigate how performance of the piezoelectric ceramic actuator influences jetting characteristics of nanosilver ink. Finally, the proposed DLEM is applied to predict the printing quality using nanosilver ink. Experimental results show that, compared to other analytic models, the proposed DLEM has a simpler structure with the sufficient simulation and prediction accuracy.

Parallelized FDTD simulation for flat-plate bounded wave EMP simulator with lumped terminator

International Nuclear Information System (INIS)

Zhu Xiangqin; Chen Weiqing; Chen Zaigao; Cai Libing; Wang Jianguo

2013-01-01

A parallelized finite-difference time-domain(FDTD) method for simulating the bounded wave electromagnetic pulse (EMP) simulator with lumped terminator and parallel plate is presented. The effects of several model-parameters on the simulator to the fields in the working volume are simulated and analyzed. The results show that if the width of the lower PEC plate is(or is bigger than)1.5 times that of the upper plate of working volume, the projection length of front transitional section does not have a significant effect on the rise-times of electric fields at the points near the front transitional section, and the rise-times of electric fields at the points near the working volume center decrease as the projection length increases, but the decrement of rise-time decreases. The rise-times of E z at all points also decrease as the lower PEC plate's width increases, but the decrements of rise-time decreases. If the projection length of the front transitional section is fixed, the good results can not be obtained by increasing or decreasing the height of the simulator only, however, which has an optimal value. (authors)

Black holes as lumps of fluid

International Nuclear Information System (INIS)

Caldarelli, Marco M.; Dias, Oscar J.C.; Emparan, Roberto; Klemm, Dietmar

2009-01-01

The old suggestive observation that black holes often resemble lumps of fluid has recently been taken beyond the level of an analogy to a precise duality. We investigate aspects of this duality, and in particular clarify the relation between area minimization of the fluid vs. area maximization of the black hole horizon, and the connection between surface tension and curvature of the fluid, and surface gravity of the black hole. We also argue that the Rayleigh-Plateau instability in a fluid tube is the holographic dual of the Gregory-Laflamme instability of a black string. Associated with this fluid instability there is a rich variety of phases of fluid solutions that we study in detail, including in particular the effects of rotation. We compare them against the known results for asymptotically flat black holes finding remarkable agreement. Furthermore, we use our fluid results to discuss the unknown features of the gravitational system. Finally, we make some observations that suggest that asymptotically flat black holes may admit a fluid description in the limit of large number of dimensions.

Sensitivity Analysis of Methane Hydrate Reservoirs: Effects of Reservoir Parameters on Gas Productivity and Economics

Science.gov (United States)

Anderson, B. J.; Gaddipati, M.; Nyayapathi, L.

2008-12-01

This paper presents a parametric study on production rates of natural gas from gas hydrates by the method of depressurization, using CMG STARS. Seven factors/parameters were considered as perturbations from a base-case hydrate reservoir description based on Problem 7 of the International Methane Hydrate Reservoir Simulator Code Comparison Study led by the Department of Energy and the USGS. This reservoir is modeled after the inferred properties of the hydrate deposit at the Prudhoe Bay L-106 site. The included sensitivity variables were hydrate saturation, pressure (depth), temperature, bottom-hole pressure of the production well, free water saturation, intrinsic rock permeability, and porosity. A two-level (L=2) Plackett-Burman experimental design was used to study the relative effects of these factors. The measured variable was the discounted cumulative gas production. The discount rate chosen was 15%, resulting in the gas contribution to the net present value of a reservoir. Eight different designs were developed for conducting sensitivity analysis and the effects of the parameters on the real and discounted production rates will be discussed. The breakeven price in various cases and the dependence of the breakeven price on the production parameters is given in the paper. As expected, initial reservoir temperature has the strongest positive effect on the productivity of a hydrate deposit and the bottom-hole pressure in the production well has the strongest negative dependence. Also resulting in a positive correlation is the intrinsic permeability and the initial free water of the formation. Negative effects were found for initial hydrate saturation (at saturations greater than 50% of the pore space) and the reservoir porosity. These negative effects are related to the available sensible heat of the reservoir, with decreasing productivity due to decreasing available sensible heat. Finally, we conclude that for the base case reservoir, the break-even price (BEP

Bubble parameters analysis of gas-liquid two-phase sparse bubbly flow based on image method

International Nuclear Information System (INIS)

Zhou Yunlong; Zhou Hongjuan; Song Lianzhuang; Liu Qian

2012-01-01

The sparse rising bubbles of gas-liquid two-phase flow in vertical pipe were measured and studied based on image method. The bubble images were acquired by high-speed video camera systems, the characteristic parameters of bubbles were extracted by using image processing techniques. Then velocity variation of rising bubbles were drawn. Area and centroid variation of single bubble were also drawn. And then parameters and movement law of bubbles were analyzed and studied. The test results showed that parameters of bubbles had been analyzed well by using image method. (authors)

Frequency method for determining the parameters of the electromagnetic brakes and slip-type couplings with solid magnetic circuits

Science.gov (United States)

Guseynov, F. G.; Abbasova, E. M.

1977-01-01

The equivalent representation of brakes and coupling by lumped circuits is investigated. Analytical equations are derived for relating the indices of the transients to the parameters of the equivalent circuits for arbitrary rotor speed. A computer algorithm is given for the calculations.

Lumped-Element Dynamic Electro-Thermal model of a superconducting magnet

Science.gov (United States)

Ravaioli, E.; Auchmann, B.; Maciejewski, M.; ten Kate, H. H. J.; Verweij, A. P.

2016-12-01

Modeling accurately electro-thermal transients occurring in a superconducting magnet is challenging. The behavior of the magnet is the result of complex phenomena occurring in distinct physical domains (electrical, magnetic and thermal) at very different spatial and time scales. Combined multi-domain effects significantly affect the dynamic behavior of the system and are to be taken into account in a coherent and consistent model. A new methodology for developing a Lumped-Element Dynamic Electro-Thermal (LEDET) model of a superconducting magnet is presented. This model includes non-linear dynamic effects such as the dependence of the magnet's differential self-inductance on the presence of inter-filament and inter-strand coupling currents in the conductor. These effects are usually not taken into account because superconducting magnets are primarily operated in stationary conditions. However, they often have significant impact on magnet performance, particularly when the magnet is subject to high ramp rates. Following the LEDET method, the complex interdependence between the electro-magnetic and thermal domains can be modeled with three sub-networks of lumped-elements, reproducing the electrical transient in the main magnet circuit, the thermal transient in the coil cross-section, and the electro-magnetic transient of the inter-filament and inter-strand coupling currents in the superconductor. The same simulation environment can simultaneously model macroscopic electrical transients and phenomena at the level of superconducting strands. The model developed is a very useful tool for reproducing and predicting the performance of conventional quench protection systems based on energy extraction and quench heaters, and of the innovative CLIQ protection system as well.

A Lumped Thermal Model Including Thermal Coupling and Thermal Boundary Conditions for High Power IGBT Modules

DEFF Research Database (Denmark)

Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede

2018-01-01

Detailed thermal dynamics of high power IGBT modules are important information for the reliability analysis and thermal design of power electronic systems. However, the existing thermal models have their limits to correctly predict these complicated thermal behavior in the IGBTs: The typically used...... thermal model based on one-dimensional RC lumps have limits to provide temperature distributions inside the device, moreover some variable factors in the real-field applications like the cooling and heating conditions of the converter cannot be adapted. On the other hand, the more advanced three......-dimensional thermal models based on Finite Element Method (FEM) need massive computations, which make the long-term thermal dynamics difficult to calculate. In this paper, a new lumped three-dimensional thermal model is proposed, which can be easily characterized from FEM simulations and can acquire the critical...

The influence of model parameters on catchment-response

International Nuclear Information System (INIS)

Shah, S.M.S.; Gabriel, H.F.; Khan, A.A.

2002-01-01

This paper deals with the study of influence of influence of conceptual rainfall-runoff model parameters on catchment response (runoff). A conceptual modified watershed yield model is employed to study the effects of model-parameters on catchment-response, i.e. runoff. The model is calibrated, using manual parameter-fitting approach, also known as trial and error parameter-fitting. In all, there are twenty one (21) parameters that control the functioning of the model. A lumped parametric approach is used. The detailed analysis was performed on Ling River near Kahuta, having catchment area of 56 sq. miles. The model includes physical parameters like GWSM, PETS, PGWRO, etc. fitting coefficients like CINF, CGWS, etc. and initial estimates of the surface-water and groundwater storages i.e. srosp and gwsp. Sensitivity analysis offers a good way, without repetititious computations, the proper weight and consideration that must be taken when each of the influencing factor is evaluated. Sensitivity-analysis was performed to evaluate the influence of model-parameters on runoff. The sensitivity and relative contributions of model parameters influencing catchment-response are studied. (author)

Separation parameters of gas centrifuges

International Nuclear Information System (INIS)

May, W.G.

1977-01-01

Early work on development of the gas centrifuge for separation of uranium isotopes has recently been reviewed. Several configurations were investigated. The preferred configuration eventually turned out to be a countercurrent centrifuge. In this form, an internal circulation is set up, and as a consequence, light isotope concentrates at one end of the centrifuge, heavy isotope at the other. In many ways the effect resembles the separation obtained in packed columns in the chemical and petroleum industries. It is the purpose of this paper to develop this analogy between countercurrent gas centrifuges and packed towers and to illustrate its usefulness in understanding the separation process in the centrifuge. 8 figures

The effect of environmental factors on breast lumps of Egyptian women in different socioeconomic levels

International Nuclear Information System (INIS)

Salama, D.H.

2008-01-01

The environmental risk factors related to the breast tumors (lumps) are essential in order to build strategies to decrease cancer incidence and mortality among different socioeconomic and cultural backgrounds. A case control study of 70 cases and 52 controls were classified into high, middle and low socioeconomic classes. The results revealed significant increased risk of breast tumors among working females, having positive family history, married with lower mean parity, with higher consumption of fatty meals, lesser meat intake. Non significant risk factors were the social class, exposure to ionizing radiation, non lactating. wearing tight bra, consumption of vegetables and fruits, oral contraceptive pill users and exposure to outdoor air pollution or indoor pollution as floors and wall paintings. In conclusion, this study highlights the positive life style for egyptian women so they can prevent some of the environmental risks of breast tumors. Increasing the awareness of breast diseases and regular examination remains the corner stone for early detection management of breast lumps.

airGRteaching: an R-package designed for teaching hydrology with lumped hydrological models

Science.gov (United States)

Thirel, Guillaume; Delaigue, Olivier; Coron, Laurent; Andréassian, Vazken; Brigode, Pierre

2017-04-01

Lumped hydrological models are useful and convenient tools for research, engineering and educational purposes. They propose catchment-scale representations of the precipitation-discharge relationship. Thanks to their limited data requirements, they can be easily implemented and run. With such models, it is possible to simulate a number of hydrological key processes over the catchment with limited structural and parametric complexity, typically evapotranspiration, runoff, underground losses, etc. The Hydrology Group at Irstea (Antony) has been developing a suite of rainfall-runoff models over the past 30 years. This resulted in a suite of models running at different time steps (from hourly to annual) applicable for various issues including water balance estimation, forecasting, simulation of impacts and scenario testing. Recently, Irstea has developed an easy-to-use R-package (R Core Team, 2016), called airGR (Coron et al., 2016, 2017), to make these models widely available. Although its initial target public was hydrological modellers, the package is already used for educational purposes. Indeed, simple models allow for rapidly visualising the effects of parameterizations and model components on flows hydrographs. In order to avoid the difficulties that students may have when manipulating R and datasets, we developed (Delaigue and Coron, 2016): - Three simplified functions to prepare data, calibrate a model and run a simulation - Simplified and dynamic plot functions - A shiny (Chang et al., 2016) interface that connects this R-package to a browser-based visualisation tool. On this interface, the students can use different hydrological models (including the possibility to use a snow-accounting model), manually modify their parameters and automatically calibrate their parameters with diverse objective functions. One of the visualisation tabs of the interface includes observed precipitation and temperature, simulated snowpack (if any), observed and simulated

Fire Detection Tradeoffs as a Function of Vehicle Parameters

Science.gov (United States)

Urban, David L.; Dietrich, Daniel L.; Brooker, John E.; Meyer, Marit E.; Ruff, Gary A.

2016-01-01

Fire survivability depends on the detection of and response to a fire before it has produced an unacceptable environment in the vehicle. This detection time is the result of interplay between the fire burning and growth rates; the vehicle size; the detection system design; the transport time to the detector (controlled by the level of mixing in the vehicle); and the rate at which the life support system filters the atmosphere, potentially removing the detected species or particles. Given the large differences in critical vehicle parameters (volume, mixing rate and filtration rate) the detection approach that works for a large vehicle (e.g. the ISS) may not be the best choice for a smaller crew capsule. This paper examines the impact of vehicle size and environmental control and life support system parameters on the detectability of fires in comparison to the hazard they present. A lumped element model was developed that considers smoke, heat, and toxic product release rates in comparison to mixing and filtration rates in the vehicle. Recent work has quantified the production rate of smoke and several hazardous species from overheated spacecraft polymers. These results are used as the input data set in the lumped element model in combination with the transport behavior of major toxic products released by overheating spacecraft materials to evaluate the necessary alarm thresholds to enable appropriate response to the fire hazard.

The Numerical Welding Simulation - Developments and Validation of Simplified and Bead Lumping Methods

International Nuclear Information System (INIS)

Baup, Olivier

2001-01-01

The aim of this work was to study the TIG multipass welding process on stainless steel, by means of numerical methods and then to work out simplified and bead lumping methods in order to reduce adjusting and realisation times of these calculations. A simulation was used as reference for the validation of these methods; after the presentation of the test series having led to the option choices of this calculation (2D generalised plane strains, elastoplastic model with an isotropic hardening, hardening restoration due to high temperatures), various simplifications were tried on a plate geometry. These simplifications related various modelling points with a correct plastic flow representation in the plate. The use of a reduced number of thermal fields characterising the bead deposit and a low number of tensile curves allow to obtain interesting results, decreasing significantly the Computing times. In addition various lumping bead methods have been studied and concerning both the shape and the thermic of the macro-deposits. The macro-deposit shapes studied are in 'L', or in layer or they represent two beads one on top of the other. Among these three methods, only those using a few number of lumping beads gave bad results since thermo-mechanical history was deeply modified near and inside the weld. Thereafter, simplified methods have been applied to a tubular geometry. On this new geometry, experimental measurements were made during welding, which allow a validation of the reference calculation. Simplified and reference calculations gave approximately the same stress fields as found on plate geometry. Finally, in the last part of this document a procedure for automatic data setting permitting to reduce significantly the calculation phase preparation is presented. It has been applied to the calculation of thick pipe welding in 90 beads; the results are compared with a simplified simulation realised by Framatome and with experimental measurements. A bead by

Distribution characteristics of interfacial parameter in downward gas-liquid two-phase flow in vertical circular tube

International Nuclear Information System (INIS)

Liu Guoqiang; Yan Changqi; Tian Daogui; Sun Licheng

2014-01-01

Experimental study was performed on distribution characteristics of interfacial parameters of downward gas-liquid flow in a vertical circular tube with the measurement by a two-sensor optical fiber probe. The test section is a circular pipe with the inner diameter of 50 mm and the length of 2000 mm. The superficial velocities of the gas and the liquid phases cover the ranges of 0.004-0.077 m/s and 0.43-0.71 m/s, respectively. The results show that the distributions of the interfacial parameters in downward bubbly flows are quite different from those in upward bubbly flows. For the case of upward flow, the parameters present the 'wall-peak' or 'core-peak' distributions, but for the case of downward flow, they show 'wall-peak' or 'wide-peak' distributions. The average value of void fraction in vertical downward flow is about 119.6%-145.0% larger than that in upward flow, and the interfacial area concentration is about 18.8%-82.5% larger than that in upward flow. The distribution of interfacial parameters shows an obvious tendency of uniformity. (authors)

Kinetic modelling of hydrocracking catalytic reactions by the single events theory; Modelisation cinetique des reactions catalytiques d`hydrocraquage par la theorie des evenements constitutifs

Energy Technology Data Exchange (ETDEWEB)

Schweitzer, J.M.

1998-11-23

Kinetic modelling of petroleum hydrocracking is particularly difficult given the complexity of the feedstocks. There are two distinct classes of kinetics models: lumped empirical models and detailed molecular models. The productivity of lumped empirical models is generally not very accurate, and the number of kinetic parameters increases rapidly with the number of lumps. A promising new methodology is the use of kinetic modelling based on the single events theory. Due to the molecular approach, a finite and limited number of kinetic parameters can describe the kinetic behaviour of the hydrocracking of heavy feedstock. The parameters are independent of the feedstock. However, the available analytical methods are not able to identify the products on the molecular level. This can be accounted for by means of an posteriori lamping technique, which incorporates the detailed knowledge of the elementary step network. Thus, the lumped kinetic parameters are directly calculated from the fundamental kinetic coefficients and the single event model is reduced to a re-lumped molecular model. Until now, the ability of the method to extrapolate to higher carbon numbers had not been demonstrated. In addition, no study had been published for three phase (gas-liquid-solid) systems and a complex feedstock. The objective of this work is to validate the `single events` method using a paraffinic feedstock. First of all, a series of experiments was conducted on a model compound (hexadecane) in order to estimate the fundamental kinetic parameters for acyclic molecules. To validate the single event approach, these estimated kinetic coefficients were used to simulate hydrocracking of a paraffinic mixture ranging from C11 to C18. The simulation results were then compared to the results obtained from the hydrocracking experiments. The comparison allowed to validate the model for acyclic molecules and to demonstrate that the model is applicable to compounds with higher carbon numbers. (author

Investigation of parameters affecting the online combination of supercritical fluid extraction with capillary gas chromatography

NARCIS (Netherlands)

Lou, X.W.; Janssen, J.G.M.; Cramers, C.A.M.G.

1996-01-01

Two different injectors, a split/splitless injector and a programmed temperature vaporizer (PTV) injector were investigated as the interface in on-line supercritical fluid extraction (SFE)-capillary gas chromatography (cGC). The parameters affecting the chromatographic peak shapes as well as the

Model parameters estimation and sensitivity by genetic algorithms

International Nuclear Information System (INIS)

Marseguerra, Marzio; Zio, Enrico; Podofillini, Luca

2003-01-01

In this paper we illustrate the possibility of extracting qualitative information on the importance of the parameters of a model in the course of a Genetic Algorithms (GAs) optimization procedure for the estimation of such parameters. The Genetic Algorithms' search of the optimal solution is performed according to procedures that resemble those of natural selection and genetics: an initial population of alternative solutions evolves within the search space through the four fundamental operations of parent selection, crossover, replacement, and mutation. During the search, the algorithm examines a large amount of solution points which possibly carries relevant information on the underlying model characteristics. A possible utilization of this information amounts to create and update an archive with the set of best solutions found at each generation and then to analyze the evolution of the statistics of the archive along the successive generations. From this analysis one can retrieve information regarding the speed of convergence and stabilization of the different control (decision) variables of the optimization problem. In this work we analyze the evolution strategy followed by a GA in its search for the optimal solution with the aim of extracting information on the importance of the control (decision) variables of the optimization with respect to the sensitivity of the objective function. The study refers to a GA search for optimal estimates of the effective parameters in a lumped nuclear reactor model of literature. The supporting observation is that, as most optimization procedures do, the GA search evolves towards convergence in such a way to stabilize first the most important parameters of the model and later those which influence little the model outputs. In this sense, besides estimating efficiently the parameters values, the optimization approach also allows us to provide a qualitative ranking of their importance in contributing to the model output. The

Metastatic uterine leiomyosarcoma presenting as a breast lump.

LENUS (Irish Health Repository)

Sibartie, S

2009-01-31

BACKGROUND: It is uncommon to encounter a breast metastasis from an extramammary malignancy and even rarer from a uterine leiomyosarcoma. AIMS: We describe the third case report in the medical literature of a breast metastasis from a uterine leiomyosarcoma. METHODS: We report the management of a 56-year-old patient who presented with a breast lump 3 years after hysterectomy for a fibroid uterus. We conducted a literature review of breast leiomyosarcomas. RESULTS: The excision of the breast mass revealed a low-grade leiomyosarcoma. Radiographic examinations demonstrated metastases to the lung, liver, pelvis and bone. Retrospective pathology review of her uterus identified a small focus of leiomyosarcoma. She received chemotherapy and palliative radiotherapy but passed away within few months. CONCLUSION: Metastasis to the breast from a non-breast primary is generally a sign of disseminated disease and; thus, a poor prognostic indicator.

Economy calculation to determine the optimum plant parameters for peak coverage with stored liquefied natural gas. [In German

Energy Technology Data Exchange (ETDEWEB)

Backhaus, H

1979-02-08

The economical supply of natural gas is faced with particular problems due to the considerably fluctuating demand as a result of the greatly varying course of temperature; the infrastructure of the gas distribution of largely fluctuating loads is particularly effected. As the utilization structure deteriorates however, the higher specific gas costs rise. It is hence necessary for gas supply optimization, to extensively adapt the gas bought to the gas sold especially when trying to compare with the import. Storage plays a key role in this. Starting with the annual normal line, mathematical relationships are developed for peak coverage wth liquefied natural gas which however, are set up in such a way that every other peak coverage process can be analyzed according to costs and the parameters optimized. A few selected model cases are treated (gas supply undertakings of various sizes, different gas drawing and supply conditions).

Advertising Pricing Models in Media Markets: Lump-Sum versus Per-Consumer Charges

OpenAIRE

Helmut Dietl; Markus Lang; Panlang Lin

2012-01-01

This paper develops a model of asymmetric competition between a pay and a free media platform. The pay media platform generates revenues from media consumers through subscription fees, while the free media platform generates revenues from charging advertisers either on a lump-sum basis (regime A) or on a per-consumer basis (regime B). We show that the free platform produces a higher advertising level and attracts more consumers in regime A than B although advertisers must pay more for ads and...

Development and optimization of operational parameters of a gas-fired baking oven

OpenAIRE

Afolabi Tunde MORAKINYO; Babatunde OMIDIJI; Hakeem OWOLABI

2017-01-01

This study presented the development and optimization of operational parameters of an indigenous gas-fired bread-baking oven for small-scale entrepreneur. It is an insulated rectangular box-like chamber, made of galvanized-steel sheets and having a total dimension of 920mm×650mm×600mm. This oven consists of two baking compartments and three combustion chambers. The oven characteristics were evaluated in terms of the baking capacity, baking efficiency and weight loss of the baked bread. The ph...

Vortices in atomic Bose-Einstein condensates in the large-gas-parameter region

International Nuclear Information System (INIS)

Nilsen, J.K.; Mur-Petit, J.; Guilleumas, M.; Polls, A.; Hjorth-Jensen, M.

2005-01-01

In this work we compare the results of the Gross-Pitaevskii and modified Gross-Pitaevskii equations with ab initio variational Monte Carlo calculations for Bose-Einstein condensates of atoms in axially symmetric traps. We examine both the ground state and excited states having a vortex line along the z axis at high values of the gas parameter and demonstrate an excellent agreement between the modified Gross-Pitaevskii and ab initio Monte Carlo methods, both for the ground and vortex states

On 4-degree-of-freedom biodynamic models of seated occupants: Lumped-parameter modeling

Science.gov (United States)

Bai, Xian-Xu; Xu, Shi-Xu; Cheng, Wei; Qian, Li-Jun

2017-08-01

It is useful to develop an effective biodynamic model of seated human occupants to help understand the human vibration exposure to transportation vehicle vibrations and to help design and improve the anti-vibration devices and/or test dummies. This study proposed and demonstrated a methodology for systematically identifying the best configuration or structure of a 4-degree-of-freedom (4DOF) human vibration model and for its parameter identification. First, an equivalent simplification expression for the models was made. Second, all of the possible 23 structural configurations of the models were identified. Third, each of them was calibrated using the frequency response functions recommended in a biodynamic standard. An improved version of non-dominated sorting genetic algorithm (NSGA-II) based on Pareto optimization principle was used to determine the model parameters. Finally, a model evaluation criterion proposed in this study was used to assess the models and to identify the best one, which was based on both the goodness of curve fits and comprehensive goodness of the fits. The identified top configurations were better than those reported in the literature. This methodology may also be extended and used to develop the models with other DOFs.

Cultural factors associated with the management of breast lumps amongst Xhosa women

Directory of Open Access Journals (Sweden)

Nosipho Mdondolo

2003-11-01

Full Text Available A qualitative research design and an ethno-nursing research method were used to identify cultural factors influencing Xhosa women’s health seeking behaviours associated with breast lumps. Opsomming ’n Kwalitatiewe navorsingsontwerp en ’n etnoverpleegkundige navorsingsmetode is gebruik. Die doel was om te bepaal watter kulturele faktore Xhosa vroue se strewe na welstand, wat in verband staan met ’n borsvergroeisel, beïnvloed. *Please note: This is a reduced version of the abstract. Please refer to PDF for full text.

Techno-economic sensitivity study of heliostat field parameters for micro-gas turbine CSP

Science.gov (United States)

Landman, Willem A.; Gauché, Paul; Dinter, Frank; Myburgh, J. T.

2017-06-01

Concentrating solar power systems based on micro-gas turbines potentially offer numerous benefits should they become commercially viable. Heliostat fields for such systems have unique requirements in that the number of heliostats and the focal ratios are typically much lower than conventional central receiver systems. This paper presents a techno-economic sensitivity study of heliostat field parameters for a micro-gas turbine central receiver system. A 100 kWe minitower system is considered for the base case and a one-at-a-time strategy is used to investigate parameter sensitivities. Increasing heliostat focal ratios are found to have significant optical performance benefits due to both a reduction in astigmatic aberrations and a reduction in the number of facet focal lengths required; confirming the hypothesis that smaller heliostats offer a techno-economic advantage. Fixed Horizontal Axis tracking mechanism is shown to outperform the conventional Azimuth Zenith tracking mechanism in high density heliostat fields. Although several improvements to heliostat field performance are discussed, the capex fraction of the heliostat field for such system is shown to be almost half that of a conventional central receiver system and optimum utilization of the higher capex components, namely; the receiver and turbine subsystems, are more rewarding than that of the heliostat field.

Influence of the solid-gas interface on the effective thermal parameters of a two-layer structure in photoacoustic experiments

International Nuclear Information System (INIS)

Aguirre, N Munoz; Perez, L MartInez; Garibay-Febles, V; Lozada-Cassou, M

2004-01-01

From the theoretical point of view, the influence of the solid-gas interface on the effective thermal parameters in a two-layer structure of the photoacoustic technique is discussed. It is shown that the effective thermal parameters depend strongly upon the thermal resistance value associated with the solid-gas interface. New expressions for the effective thermal conductivity and thermal diffusivity in the low frequency limit are obtained. In the high frequency limit, the 'resonant' behaviour of the effective thermal diffusivity is maintained and a new complex dependence on frequency of the effective thermal conductivity is shown

Thermodynamic parameters and transport coefficients of the U-C-F gas mixture in the steady flow gaseous core fission reactor

International Nuclear Information System (INIS)

Berg, M.S. van den.

1995-01-01

Thermodynamic parameters and transport coefficients have been calculated for a multicomponent reacting U-C-F gas mixture in the steady flow gaseous core fission reactor. Element abundances are consistent with thermodynamic equilibrium between the gas mixture and a cooled solid graphite wall at 2500 K. Results are presented for various pressures, a fluorine potential of 5.6 and temperatures between 2500 and 7000 K. As a result of dissociation processes of uranium and carbon fluoride compounds, ''effective'' values of thermodynamic parameters and transport coefficients show anomalous behaviour with respect to so-called ''frozen'' values. The chemical reaction energy of the U-C-F gas mixture has been calculated as the driving-force behind the process of fuel redistribution to attain criticality conditions inside a functioning reactor. (author)

New Procedure to Develop Lumped Kinetic Models for Heavy Fuel Oil Combustion

KAUST Repository

Han, Yunqing

2016-09-20

A new procedure to develop accurate lumped kinetic models for complex fuels is proposed, and applied to the experimental data of the heavy fuel oil measured by thermogravimetry. The new procedure is based on the pseudocomponents representing different reaction stages, which are determined by a systematic optimization process to ensure that the separation of different reaction stages with highest accuracy. The procedure is implemented and the model prediction was compared against that from a conventional method, yielding a significantly improved agreement with the experimental data. © 2016 American Chemical Society.

SURVIVING OF COMMERCIAL PROBIOTIC STRAIN Lactobacillus rhamnosus GG IN SLOVAK COW LUMP CHEESE EXPERIMENTALLY INOCULATED WITH Listeria innocua

Directory of Open Access Journals (Sweden)

Andrea Lauková

2014-08-01

Full Text Available Cow lump cheese represents a traditional Slovak cheese. It belongs to fresh types of cheeses. The aim of this study was to test surviving of commercial probiotic strain Lactobacillus rhamnosus GG in cow lump cheese experimentally infected with L. innocua; (listeriae are contaminants and to check the suitability of GG strain as additive for this product. The counts of GG strain in cow lump cheeses were well balanced during whole experiment. It was found in the counts from 5.48 ± 0.15 to 7.77 ±1.50 log10 cfu/g. Its maximum in cheese was 7.77 ± 1.30 log10 cfu/g on day 7 with stability up to day 14. The identity of GG strain isolated from cheeses was confirmed by PCR. The counts of other lactic acid bacteria were also well balanced during the whole experiment in the experimental cheeses with stability up to day 14. Only in E1/GG cheese, the highest number of LAB was detected (10.60 ±1.26 log10 cfu/g. The count of L. innocua LMG 13568 was not influenced. The pH and lactic acid values were not negatively influenced. Visually, the GG cheese provided a good structure (consistency.It can be disputed that shelf-life of the product could be maintained by this way and/or the product itself with GG strain can be consumed as afunctional food or to serve as a probiotic strain carrier.

Gas migration in KBS-3 buffer bentonite. Sensitivity of test parameters to experimental boundary conditions

Energy Technology Data Exchange (ETDEWEB)

Harrington, J.F.; Horseman, S.T. [British Geological Survey, Nottingham (United Kingdom)

2003-01-01

In the current Swedish repository design concept, hydrogen gas can be generated inside a waste canister by anaerobic corrosion of the ferrous metal liner. If the gas generation rate exceeds the diffusion rate of gas molecules in the buffer porewater, gas will accumulate in the void-space of a canister until its pressure becomes large enough for it to enter the bentonite as a discrete gaseous phase. Three long tenn gas injection tests have been performed on cylinders of pre-compacted MX80 bentonite. Two of these tests were undertaken using a custom-designed constant volume and radial flow (CVRF) apparatus. Gas was injected at a centrally located porous filter installed in the clay before hydration. Arrangements were made for gas to flow to three independently monitored sink-filter arrays mounted around the specimen. Axial and radial total stresses and internal porewater pressures were continuously monitored. Breakthrough and peak gas pressures were substantially larger than the sum of the swelling pressure and the external porewater. The third test was performed. using an apparatus which radially constrains the specimen during gas flow. Observed sensitivity of the breakthrough and peak gas pressures to the test boundary conditions suggests that gas entry must be accompanied by dilation of the bentonite fabric. In other words, there is a tendency for the volume of the specimen to increase during this process. The experimental evidence is consistent with the flow of gas along a relatively small number of crack-like pathways which propagate through the clay as gas pressure increases. Gas entry and breakthrough under constant volume boundary conditions causes a substantial increase in the total stress and the internal porewater pressure. It is possible to determine the point at which gas enters the clay by monitoring changes in these parameters. Localisation of gas flow within multiple pathways results, in nonuniform discharge rates at the sinks. When gas injection

Gas migration in KBS-3 buffer bentonite. Sensitivity of test parameters to experimental boundary conditions

International Nuclear Information System (INIS)

Harrington, J.F.; Horseman, S.T.

2003-01-01

In the current Swedish repository design concept, hydrogen gas can be generated inside a waste canister by anaerobic corrosion of the ferrous metal liner. If the gas generation rate exceeds the diffusion rate of gas molecules in the buffer porewater, gas will accumulate in the void-space of a canister until its pressure becomes large enough for it to enter the bentonite as a discrete gaseous phase. Three long tenn gas injection tests have been performed on cylinders of pre-compacted MX80 bentonite. Two of these tests were undertaken using a custom-designed constant volume and radial flow (CVRF) apparatus. Gas was injected at a centrally located porous filter installed in the clay before hydration. Arrangements were made for gas to flow to three independently monitored sink-filter arrays mounted around the specimen. Axial and radial total stresses and internal porewater pressures were continuously monitored. Breakthrough and peak gas pressures were substantially larger than the sum of the swelling pressure and the external porewater. The third test was performed. using an apparatus which radially constrains the specimen during gas flow. Observed sensitivity of the breakthrough and peak gas pressures to the test boundary conditions suggests that gas entry must be accompanied by dilation of the bentonite fabric. In other words, there is a tendency for the volume of the specimen to increase during this process. The experimental evidence is consistent with the flow of gas along a relatively small number of crack-like pathways which propagate through the clay as gas pressure increases. Gas entry and breakthrough under constant volume boundary conditions causes a substantial increase in the total stress and the internal porewater pressure. It is possible to determine the point at which gas enters the clay by monitoring changes in these parameters. Localisation of gas flow within multiple pathways results, in nonuniform discharge rates at the sinks. When gas injection

The value of arterial blood gas parameters for prediction of mortality in survivors of out-of-hospital cardiac arrest

Directory of Open Access Journals (Sweden)

Katharina Isabel von Auenmueller

2017-01-01

Full Text Available Context: Sudden cardiac death is one of the leading causes of death in Europe, and early prognostication remains challenging. There is a lack of valid parameters for the prediction of survival after cardiac arrest. Aims: This study aims to investigate if arterial blood gas parameters correlate with mortality of patients after out-of-hospital cardiac arrest. Materials and Methods: All patients who were admitted to our hospital after resuscitation following out-of-hospital cardiac arrest between January 1, 2008, and December 31, 2013, were included in this retrospective study. The patient's survival 5 days after resuscitation defined the study end-point. For the statistical analysis, the mean, standard deviation, Student's t-test, Chi-square test, and logistic regression analyses were used (level of significance P< 0.05. Results: Arterial blood gas samples were taken from 170 patients. In particular, pH < 7.0 (odds ratio [OR]: 7.20; 95% confidence interval [CI]: 3.11–16.69; P< 0.001 and lactate ≥ 5.0 mmol/L (OR: 6.79; 95% CI: 2.77–16.66; P< 0.001 showed strong and independent correlations with mortality within the first 5 days after hospital admission. Conclusion: Our study results indicate that several arterial blood gas parameters correlate with mortality of patients after out-of-hospital resuscitation. The most relevant parameters are pH and lactate because they are strongly and independently associated with mortality within the first 5 days after resuscitation. Despite this correlation, none of these parameters by oneself is strong enough to allow an early prognostication. Still, these parameters can contribute as part of a multimodal approach to assessing the patients' prognosis.

Shale Gas in Poland: an Analysis of Tax Mechanisms and Dynamic Interactions

Directory of Open Access Journals (Sweden)

Dawid Walentek

2016-12-01

Full Text Available This is a preliminary research into possible taxation mechanisms for firms that will be operating in the shale gas industry in Poland and potential market interactions between the incumbents and the entrants. The study places focus on the level of welfare and it includes a static and a dynamic analysis. The result of the former is that the lump sum tax is the first best of all considered tax mechanisms for the Polish shale gas from the welfare perspective. The second best option for taxation is a combination of the current CIT rate and a windfall profit tax. In respect to the dynamic analysis, the results suggest that Gazprom can remain the market leader in Poland even if the shale gas producers start to operate, due to the sequential character of the competition in the Polish natural gas market. Counterintuitively, it will not come at the expenses of the consumers in Poland and it can bring potential welfare gains

Comparison of Lumped and Distributed Hydrologic Models Used for Planning and Water Resources Management at the Combeima River Basin, Colombia.

Science.gov (United States)

Salgado, F., II; Vélez, J.

2014-12-01

The catchment area is considered as the planning unit of natural resources where multiple factors as biotic, abiotic and human interact in a web of relationships making this unit a complex system. It is also considered by several authors as the most suitable unit for studying the water movement in nature and a tool for the understanding of natural processes. This research implements several hydrological models commonly used in water resources management and planning. It is the case of Témez, abcd, T, P, ARMA (1,1), and the lumped conceptual model TETIS. This latest model has been implemented in its distributed version for comparison purposes and it has been the basis for obtaining information, either through the reconstruction of natural flow series, filling missing data, forecasting or simulation. Hydrological models make use of lumped data of precipitation and potential evapotranspiration, as well as the following parameters for each one of the models which are related to soil properties as capillary storage capacity; the hydraulic saturated conductivity of the upper and lower layers of the soil, and residence times in the flow surface, subsurface layers and base flow. The calibration and the validation process of the models were performed making adjustments to the parameters listed above, taking into account the consistency in the efficiency indexes and the adjustment between the observed and simulated flows using the flow duration curve. The Nash index gave good results for the TETIS model and acceptable values were obtained to the other models. The calibration of the distributed model was complex and its results were similar to those obtained with the aggregated model. This comparison allows planners to use the hydrological multimodel techniques to reduce the uncertainty associated with planning processes in developing countries. Moreover, taking into account the information limitations required to implement a hydrological models, this application can be a

Comparison of Genetic Parameters Estimation of Fatty Acids from Gas Chromatography and FT-IR in Holsteins

DEFF Research Database (Denmark)

Poulsen, Nina Aagaard; Eskildsen, Carl Emil; Skov, T.

or on fatty acids data measured from gas chromatography in 371 Danish Holstein cows. Results showed similar heritability estimates and strong genomic correlations for most of the fatty acids. However, for some fatty acids, the choice of data affected the genetic parameter estimation, which may be due...

Unusual Presentation of Hydatidosis - Neck Lump Causing Costo-Vertebral Erosion.

Science.gov (United States)

Alam, Mehtab; Hasan, Syed-Abrar; Hashmi, Shahab-Farkhund

2016-09-01

Hydatid disease caused by larval stage of Echinococcus has been recognized endemically in many countries. Liver and lungs are the most commonly affected organs. Involvement of the head and neck region is rare and bony erosion due to hydatidosis is even rarer. We report a case of a 17-year-old girl from a poor socio-economic background who presented with a right sided supraclavicular lump, which after surgical excision and histopathological examination was diagnosed as hydatid cyst of neck. Because of its rarity in the neck region, primary diagnosis of hydatid cyst is overlooked and usually not included in the differential diagnosis of cystic neck swellings. A high index of suspicion is necessary to diagnose hydatid disease in an unusual location even in endemic areas.

An approach for characterization and lumping of plus fractions of heavy oil

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, I.; Hamouda, A.A. [Stavanger Univ., Stavanger (Norway)

2008-10-15

The constituents of hydrocarbons can be classified as either well-defined components or undefined petroleum fractions. This paper presented a newly developed method for characterizing plus fractions of heavy oil, which is particularly important for fluids with high molecular weight and high density. Characterization of plus fractions typically consists of 3 parts, notably splitting the fraction into a certain number of components groups called single carbon number (SCN); estimating the physico-chemical properties of the SCN; and lumping the generated SCN. SCN groups contain hundreds of isomers/components with the same number of carbon atoms. A unique molecular weight cannot be assigned for each SCN group because of the uncertainty of the isomers/components present. Therefore, this work focused on finding a new approach to characterize the undetermined fraction by first splitting the carbon number fraction into a representative number of SCN and then calculating their mole fraction and molecular weight. The method was based on the relationships between three parameter gamma distribution (TPG), experimental mole fraction, molecular weight and SCN data obtained from literature and industry. The method was applied to 5 different heavy oil sample fluids which all showed a left skewed distribution of the mole fraction as a function of carbon number. The predicted molecular weight was found to be close to the generalized molecular weight associated with carbon number, but it differed from one sample to another. 19 refs., 11 tabs., 15 figs.

Foreign body granuloma in the anterior abdominal wall mimicking an acute appendicular lump and induced by a translocated copper-T intrauterine contraceptive device: a case report

Directory of Open Access Journals (Sweden)

Ansari Maulana Mohammed

2009-04-01

Full Text Available Abstract Introduction Intrauterine contraceptive devices may at times perforate and migrate to adjacent organs. Such uterine perforation usually passes unnoticed with development of potentially serious complications. Case presentation A 25-year-old woman of North Indian origin presented with an acute tender lump in the right iliac fossa. The lump was initially thought to be an appendicular lump and treated conservatively. Resolution of the lump was incomplete. On exploratory laparotomy, a hard suspicious mass was found in the anterior abdominal wall of the right iliac fossa. Wide excision and bisection of the mass revealed a copper-T embedded inside. Examination of the uterus did not show any evidence of perforation. The next day, the patient gave a history of past copper-T Intrauterine contraceptive device insertion. Conclusions Copper-T insertion is one of the simplest contraceptive methods but its neglect with inadequate follow-up may lead to uterine perforation and extra-uterine migration. Regular self-examination for the "threads" supplemented with abdominal X-ray and/or ultrasound in the follow-up may detect copper-T migration early. To the best of our knowledge, this is the first report of intrauterine contraceptive device migration to the anterior abdominal wall of the right iliac fossa.

A distributed parameter model of transmission line transformer for high voltage nanosecond pulse generation.

Science.gov (United States)

Li, Jiangtao; Zhao, Zheng; Li, Longjie; He, Jiaxin; Li, Chenjie; Wang, Yifeng; Su, Can

2017-09-01

A transmission line transformer has potential advantages for nanosecond pulse generation including excellent frequency response and no leakage inductance. The wave propagation process in a secondary mode line is indispensable due to an obvious inside transient electromagnetic transition in this scenario. The equivalent model of the transmission line transformer is crucial for predicting the output waveform and evaluating the effects of magnetic cores on output performance. However, traditional lumped parameter models are not sufficient for nanosecond pulse generation due to the natural neglect of wave propagations in secondary mode lines based on a lumped parameter assumption. In this paper, a distributed parameter model of transmission line transformer was established to investigate wave propagation in the secondary mode line and its influential factors through theoretical analysis and experimental verification. The wave propagation discontinuity in the secondary mode line induced by magnetic cores is emphasized. Characteristics of the magnetic core under a nanosecond pulse were obtained by experiments. Distribution and formation of the secondary mode current were determined for revealing essential wave propagation processes in secondary mode lines. The output waveform and efficiency were found to be affected dramatically by wave propagation discontinuity in secondary mode lines induced by magnetic cores. The proposed distributed parameter model was proved more suitable for nanosecond pulse generation in aspects of secondary mode current, output efficiency, and output waveform. In depth, comprehension of underlying mechanisms and a broader view of the working principle of the transmission line transformer for nanosecond pulse generation can be obtained through this research.

Optimization of PAM-4 transmitters based on lumped silicon photonic MZMs for high-speed short-reach optical links.

Science.gov (United States)

Zhou, Shiyu; Wu, Hsin-Ta; Sadeghipour, Khosrov; Scarcella, Carmelo; Eason, Cormac; Rensing, Marc; Power, Mark J; Antony, Cleitus; O'Brien, Peter; Townsend, Paul D; Ossieur, Peter

2017-02-20

We demonstrate how to optimize the performance of PAM-4 transmitters based on lumped Silicon Photonic Mach-Zehnder Modulators (MZMs) for short-reach optical links. Firstly, we analyze the trade-off that occurs between extinction ratio and modulation loss when driving an MZM with a voltage swing less than the MZM's Vπ. This is important when driver circuits are realized in deep submicron CMOS process nodes. Next, a driving scheme based upon a switched capacitor approach is proposed to maximize the achievable bandwidth of the combined lumped MZM and CMOS driver chip. This scheme allows the use of lumped MZM for high speed optical links with reduced RF driver power consumption compared to the conventional approach of driving MZMs (with transmission line based electrodes) with a power amplifier. This is critical for upcoming short-reach link standards such as 400Gb/s 802.3 Ethernet. The driver chip was fabricated using a 65nm CMOS technology and flip-chipped on top of the Silicon Photonic chip (fabricated using IMEC's ISIPP25G technology) that contains the MZM. Open eyes with 4dB extinction ratio for a 36Gb/s (18Gbaud) PAM-4 signal are experimentally demonstrated. The electronic driver chip has a core area of only 0.11mm2 and consumes 236mW from 1.2V and 2.4V supply voltages. This corresponds to an energy efficiency of 6.55pJ/bit including Gray encoder and retiming, or 5.37pJ/bit for the driver circuit only.

Multi-time-step ahead daily and hourly intermittent reservoir inflow prediction by artificial intelligent techniques using lumped and distributed data

Science.gov (United States)

Jothiprakash, V.; Magar, R. B.

2012-07-01

SummaryIn this study, artificial intelligent (AI) techniques such as artificial neural network (ANN), Adaptive neuro-fuzzy inference system (ANFIS) and Linear genetic programming (LGP) are used to predict daily and hourly multi-time-step ahead intermittent reservoir inflow. To illustrate the applicability of AI techniques, intermittent Koyna river watershed in Maharashtra, India is chosen as a case study. Based on the observed daily and hourly rainfall and reservoir inflow various types of time-series, cause-effect and combined models are developed with lumped and distributed input data. Further, the model performance was evaluated using various performance criteria. From the results, it is found that the performances of LGP models are found to be superior to ANN and ANFIS models especially in predicting the peak inflows for both daily and hourly time-step. A detailed comparison of the overall performance indicated that the combined input model (combination of rainfall and inflow) performed better in both lumped and distributed input data modelling. It was observed that the lumped input data models performed slightly better because; apart from reducing the noise in the data, the better techniques and their training approach, appropriate selection of network architecture, required inputs, and also training-testing ratios of the data set. The slight poor performance of distributed data is due to large variations and lesser number of observed values.

New lumped-mass-stick model based on modal characteristics of structures: development and application to a nuclear containment building

Science.gov (United States)

Roh, Hwasung; Lee, Huseok; Lee, Jong Seh

2013-06-01

In this study, a new lumped-mass-stick model (LMSM) is developed based on the modal characteristics of a structure such as eigenvalues and eigenvectors. The simplified model, named the "frequency adaptive lumped-massstick model," hasonly a small number of stick elements and nodes to provide the same natural frequencies of the structure and is applied to a nuclear containment building. To investigate the numerical performance of the LMSM, a time history analysis is carried out on both the LMSM and the finite element model (FEM) for a nuclear containment building. A comparison of the results shows that the dynamic responses of the LMSM in terms of displacement and acceleration are almost identical to those of the FEM. In addition, the results in terms of fl oor response spectra at certain elevations are also in good agreement.

Determination of heat flows inside turbochargers by means of a one dimensional lumped model

OpenAIRE

Olmeda González, Pablo Cesar; Dolz Ruiz, Vicente; Arnau Martínez, Francisco José; Reyes Belmonte, Miguel Angel

2013-01-01

In the present paper, a methodology to calculate the heat fluxes inside a turbocharger from diesel passenger car is presented. The heat transfer phenomenon is solved by using a one dimensional lumped model that takes into account both the heat fluxes between the different turbocharger elements, as well as the heat fluxes between the working fluids and the turbocharger elements. This heat transfer study is supported by the high temperature differences between the working fluids passing thr...

Isolated tear of the tendon to the medial head of gastrocnemius presenting as a painless lump in the calf.

Science.gov (United States)

Watura, Christopher; Harries, William

2009-01-01

We report on a case of isolated tear of the medial head of gastrocnemius tendon. The patient presented with a painless lump in the right calf and denied any prior history of trauma or strain to the leg. A longitudinal split of the tendon was demonstrated at ultrasound and magnetic resonance imaging (MRI). There were no other abnormalities and the gastrocnemius muscle was normal. There are no reports in the literature of isolated gastrocnemius tendon tear. To date the calf muscle complex injury described in this area is tearing of the medial head of gastrocnemius muscle, sometimes referred to as "tennis leg". We conclude that an isolated tear of the tendon to the medial head of gastrocnemius should be considered in the differential diagnosis of a lump or swelling in the upper medial area of the calf and we recommend ultrasound or MRI as the investigations of choice.

Dynamic simulation of a pilot scale vacuum gas oil hydrocracking unit by the space-time CE/SE method

Energy Technology Data Exchange (ETDEWEB)

Sadighi, S.; Ahmad, A. [Institute of Hydrogen Economy, Universiti Teknologi Malaysia, Johor Bahru (Malaysia); Shirvani, M. [Faculty of Chemical Engineering, University of Science and Technology, Tehran (Iran, Islamic Republic of)

2012-05-15

This work introduces a modified space-time conservation element/solution element (CE/SE) method for the simulation of the dynamic behavior of a pilot-scale hydrocracking reactor. With this approach, a four-lump dynamic model including vacuum gas oil (VGO), middle distillate, naphtha and gas is solved. The proposed method is capable of handling the stiffness of the partial differential equations resulting from the hydrocracking reactions. To have a better judgment, the model is also solved by the finite difference method (FDM), and the results from both approaches are compared. Initially, the absolute average deviation of the cold dynamic simulation using the CE/SE approach is 8.98 %, which is better than that obtained using the FDM. Then, the stability analysis proves that for achieving an appropriate response from the dynamic model, the Courant number, which is a function of the time step size, mesh size and volume flow rate through the catalytic bed, should be less than 1. Finally, it is found that, following a careful selection of these parameters, the CE/SE solutions to the hydrocracking model can produce higher accuracy than the FDM results. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Cytological and Pathological Correlation of FNAC in Assessing Breast Lumps and Axillary Lymph Node Swellings in a Public Sector Hospital in India

Directory of Open Access Journals (Sweden)

Vasu Reddy Challa

2013-01-01

Full Text Available Background. Breast lumps have varied pathology, and there are different techniques to prove the diagnosis. The aim of the present study is to analyze the role of fine needle aspiration cytology (FNAC of the breast lesions at our center. Methods. We had retrospectively analysed 854 patients who underwent FNAC for primary breast lumps and 190 patients who underwent FNAC for an axillary lymph node in the year 2010. Results. Of 854 patients, histological correlation was available in 723 patients. The analysis was done for 812 patients as medical records were not available for 42 patients. FNAC was false negative in seven cases; 2 cases of phyllodes were reported as fibroadenoma, and 5 cases of carcinoma were diagnosed as atypical hyperplasia. The sensitivity, specificity, and false negative value of FNAC in diagnosing breast lumps were 99% (715/723, 100%, and 1%, respectively. Of 190 patients for whom FNAC was performed for axilla, 170 had proven to have axillary lymph node metastases, and the rest had reactive hyperplasia or inflammatory cells. Conclusions. FNAC is rapid, accurate, outpatient based, and less complicated procedure and helps in diagnosis of breast cancer, benign diseases, and axillary involvement in experienced hands with less chance of false results.

Wellhead to wire utilization of remote gas resources

International Nuclear Information System (INIS)

Harris, R.A.; Hines, T.L.

1998-01-01

Utilization of remote gas resources in developing countries continues to offer challenges and opportunities to producers and contractors. The Aguaytia Gas and Power Project is an example where perseverance and creativity resulted in successful utilization of natural gas resources in the Ucayali Region of Central Peru, a country which previously had no natural gas infrastructure. The resource for the project was first discovered by Mobil in 1961, and remained undeveloped for over thirty years due to lack of infrastructure and markets. Maple Gas won a competitively bid contract to develop the Aguaytia gas reserves in March of 1993. The challenges facing Maple Gas were to develop downstream markets for the gas, execute contracts with Perupetro S.A. and other Peruvian government entities, raise financing for the project, and solicit and execute engineering procurement and construction (EPC) contracts for the execution of the project. The key to development of the downstream markets was the decision to generate electric power and transmit the power over the Andes to the main electrical grid along the coast of Peru. Supplemental revenue could be generated by gas sales to a small regional power plant and extraction of LPG and natural gasoline for consumption in the Peruvian market. Three separate lump sum contracts were awarded to Asea Brown Boveri (ABB) companies for the gas project, power project and transmission project. Each project presented its unique challenges, but the commonalities were the accelerated schedule, high rainfall in a prolonged wet season and severe logistics due to lack of infrastructure in the remote region. This presentation focuses on how the gas plant contractor, ABB Randall, working in harmony with the developer, Maple Gas, tackled the challenges to monetize a remote gas resource

Optimization of Cutting Parameters of the Haynes 718 Nickel Alloy With Gas CO2 Laser

Directory of Open Access Journals (Sweden)

Jana PETRŮ

2011-06-01

Full Text Available This article deals with the application of laser technology and the optimization of parameters in the area of nickel alloy laser cutting intended for application in the aircraft industry. The main goal is to outline possibilities of use of the laser technology, primarily its application in the area of 3D material cutting. This experiment is focused on the optimization of cutting parameters of the Haynes 718 alloy with a gas CO2 laser. Originating cuts are evaluated primarily from the point of view of cut quality and accompanying undesirable phenomena occurring in the process of cutting. In conclusion the results achieved in the metallographic laboratory are described and analyzed.

Development and optimization of operational parameters of a gas-fired baking oven

Directory of Open Access Journals (Sweden)

Afolabi Tunde MORAKINYO

2017-12-01

Full Text Available This study presented the development and optimization of operational parameters of an indigenous gas-fired bread-baking oven for small-scale entrepreneur. It is an insulated rectangular box-like chamber, made of galvanized-steel sheets and having a total dimension of 920mm×650mm×600mm. This oven consists of two baking compartments and three combustion chambers. The oven characteristics were evaluated in terms of the baking capacity, baking efficiency and weight loss of the baked bread. The physical properties of the baked breads were measured and analyzed using Duncan multiple range test of one way ANOVA at significant level of p<0.05. These properties were optimized to determine the optimum baking temperature using 3D surface response plot of Statistical Release 7. The baking capacity, baking efficiency, weight loss and optimum baking temperature were: 12.5 kg/hr, 87.8%, 12.5 g, 200-220oC, respectively. The physical properties of baked bread dough were found to correspond with the imported product (control sample. These results showed that, the developed gas-fired baking oven can be adopted for baking of bread at domestic and commercial levels.

Mammographic and sonographic findings of steatocystoma multiplex presenting as breast lumps.

Science.gov (United States)

Wan, John Mun Chin; Wong, Jill Su Lin; Tee, Shang-Ian

2012-12-01

Steatocystoma multiplex (SM) is an uncommon cutaneous disorder characterised by multiple intradermal cysts distributed over the trunk and proximal extremities. This condition affects both genders and is often inherited as an autosomal dominant trait, although sporadic cases have been described. This report describes the mammographic and sonographic features of the cysts, which presented as breast lumps, for evaluation. The cysts appeared as numerous well-circumscribed, radiolucent nodules with thin radiodense rims on mammography. On sonography, the cysts could be hypoechoic, isoechoic or demonstrate mixed echoes containing debris-fluid levels, depending on the amount of clear oily liquid and keratinous material. SM can be diagnosed based on a clinical setting of multiple asymptomatic small intradermal nodules over the trunk and proximal extremities, positive family history and imaging findings.

Kinetic model framework for aerosol and cloud surface chemistry and gas-particle interactions - Part 1: General equations, parameters, and terminology

Science.gov (United States)

Pöschl, U.; Rudich, Y.; Ammann, M.

2007-12-01

Aerosols and clouds play central roles in atmospheric chemistry and physics, climate, air pollution, and public health. The mechanistic understanding and predictability of aerosol and cloud properties, interactions, transformations, and effects are, however, still very limited. This is due not only to the limited availability of measurement data, but also to the limited applicability and compatibility of model formalisms used for the analysis, interpretation, and description of heterogeneous and multiphase processes. To support the investigation and elucidation of atmospheric aerosol and cloud surface chemistry and gas-particle interactions, we present a comprehensive kinetic model framework with consistent and unambiguous terminology and universally applicable rate equations and parameters. It enables a detailed description of mass transport and chemical reactions at the gas-particle interface, and it allows linking aerosol and cloud surface processes with gas phase and particle bulk processes in systems with multiple chemical components and competing physicochemical processes. The key elements and essential aspects of the presented framework are: a simple and descriptive double-layer surface model (sorption layer and quasi-static layer); straightforward flux-based mass balance and rate equations; clear separation of mass transport and chemical reactions; well-defined and consistent rate parameters (uptake and accommodation coefficients, reaction and transport rate coefficients); clear distinction between gas phase, gas-surface, and surface-bulk transport (gas phase diffusion, surface and bulk accommodation); clear distinction between gas-surface, surface layer, and surface-bulk reactions (Langmuir-Hinshelwood and Eley-Rideal mechanisms); mechanistic description of concentration and time dependences (transient and steady-state conditions); flexible addition of unlimited numbers of chemical species and physicochemical processes; optional aggregation or resolution

Effect of wind waves on air-sea gas exchange: proposal of an overall CO2 transfer velocity formula as a function of breaking-wave parameter

International Nuclear Information System (INIS)

Zhao, D.; Suzuki, Y.; Komori, S.

2003-01-01

A new formula for gas transfer velocity as a function of the breaking-wave parameter is proposed based on correlating gas transfer with whitecap coverage. The new formula for gas transfer across an air-sea interface depends not only on wind speed but also on wind-wave state. At the same wind speed, a higher gas transfer velocity will be obtained for a more developed wind-sea, which is represented by a smaller spectral peak frequency of wind waves. We suggest that the large uncertainties in the traditional relationship of gas transfer velocity with wind speed be ascribed to the neglect of the effect of wind waves. The breaking-wave parameter can be regarded as a Reynolds number that characterizes the intensity of turbulence associated with wind waves in the downward-bursting boundary layer (DBBL). DBBL provides an effective way to exchange gas across the air-sea interface, which might be related to the surface renewal

Using lumped modelling for providing simple metrics and associated uncertainties of catchment response to agricultural-derived nitrates pollutions

Science.gov (United States)

RUIZ, L.; Fovet, O.; Faucheux, M.; Molenat, J.; Sekhar, M.; Aquilina, L.; Gascuel-odoux, C.

2013-12-01

The development of simple and easily accessible metrics is required for characterizing and comparing catchment response to external forcings (climate or anthropogenic) and for managing water resources. The hydrological and geochemical signatures in the stream represent the integration of the various processes controlling this response. The complexity of these signatures over several time scales from sub-daily to several decades [Kirchner et al., 2001] makes their deconvolution very difficult. A large range of modeling approaches intent to represent this complexity by accounting for the spatial and/or temporal variability of the processes involved. However, simple metrics are not easily retrieved from these approaches, mostly because of over-parametrization issues. We hypothesize that to obtain relevant metrics, we need to use models that are able to simulate the observed variability of river signatures at different time scales, while being as parsimonious as possible. The lumped model ETNA (modified from[Ruiz et al., 2002]) is able to simulate adequately the seasonal and inter-annual patterns of stream NO3 concentration. Shallow groundwater is represented by two linear stores with double porosity and riparian processes are represented by a constant nitrogen removal function. Our objective was to identify simple metrics of catchment response by calibrating this lumped model on two paired agricultural catchments where both N inputs and outputs were monitored for a period of 20 years. These catchments, belonging to ORE AgrHys, although underlain by the same granitic bedrock are displaying contrasted chemical signatures. The model was able to simulate the two contrasted observed patterns in stream and groundwater, both on hydrology and chemistry, and at the seasonal and pluri-annual scales. It was also compatible with the expected trends of nitrate concentration since 1960. The output variables of the model were used to compute the nitrate residence time in both the

Analysis of transient thermal response in the outlet plenum of an LMFBR

International Nuclear Information System (INIS)

Yang, J.W.

1976-05-01

A two-zone mixing model based on the lumped-parameter approach was developed for the analysis of transient thermal response in the upper outlet plenum of an LMFBR. The one-dimensional turbulent jet flow equations were solved to determine the maximum penetration of the core flow. The maximum penetration is used as the criterion for dividing the sodium region into two mixing zones. The lumped-parameter model considers the transient sodium temperature affected by the thermal expansion of sodium, heat transfer with cover gas, heat capacity of different sections of metal and the addition of bypass flow into the plenum. Numerical calculations were performed for two cases. The first case corresponds to a normal scram followed by flow coast-down. The second case represents the double-ended pipe rupture at the inlet of cold leg followed by reactor scram. The results indicate that effects of flow stratification, chimney height, metal heat capacity and bypass flow are important for transient sodium temperature calculation. Thermal expansion of sodium and heat transfer with the cover gas does not play any significant role on sodium temperature. This two-zone mixing model will be a part of the thermohydraulic transient code SSC

Generalized model development for a cryo-adsorber and 1-D results for the isobaric refueling period

Energy Technology Data Exchange (ETDEWEB)

Kumar, V. Senthil [India Science Lab, General Motors Global R and D, Creator Building, International Technology Park, Bangalore 560066 (India); Kumar, Sudarshan [Chemical Sciences and Material Systems Lab, General Motors Global R and D, Warren Technical Center Campus, 30500 Mound Road, Warren, MI 48090 (United States)

2010-04-15

We have developed 3-D model equations for a cryo-adsorption hydrogen storage tank, where the energy balance accommodates the temperature and pressure variation of all the thermodynamic properties. We then reduce the 3-D model to the 1-D isobaric system and study the isobaric refueling period, for simplified geometry and charging conditions. The hydrogen capacity evolution predicted by the 1-D axial bed model is significantly different than that predicted by the lumped-parameter model because of the presence of sharp temperature gradients during refueling. The 1-D model predicts a higher hydrogen capacity than the lumped-parameter model. This observation can be rationalized by the fact that a bed with temperature gradients on equilibration should desorb gas, whenever the adsorbed phase entropy is lower than the gas phase entropy. The 1-D analysis of the isobaric refueling period does not show any significant difference in hydrogen capacity evolution among the axial, single and multicartridge annular bed designs. Hence, a multicartridge annular design, though giving a slightly lower pressure drop, does not offer any heat and mass transfer enhancement over the single cartridge design. And, the single cartridge annular design appears to be optimal. (author)

A passive terahertz video camera based on lumped element kinetic inductance detectors

Energy Technology Data Exchange (ETDEWEB)

Rowe, Sam, E-mail: sam.rowe@astro.cf.ac.uk; Pascale, Enzo; Doyle, Simon; Dunscombe, Chris; Hargrave, Peter; Papageorgio, Andreas; Ade, Peter A. R.; Barry, Peter; Bideaud, Aurélien; Brien, Tom; Dodd, Chris; House, Julian; Moseley, Paul; Sudiwala, Rashmi; Tucker, Carole; Walker, Ian [Astronomy Instrumentation Group, School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Wood, Ken [QMC Instruments Ltd., School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Grainger, William [Rutherford Appleton Laboratory, STFC, Swindon SN2 1SZ (United Kingdom); Mauskopf, Philip [Astronomy Instrumentation Group, School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); School of Earth Science and Space Exploration, Arizona State University, Tempe, Arizona 85281 (United States); Spencer, Locke [Department of Physics and Astronomy, University of Lethbridge, Lethbridge, Alberta T1K 3M4 (Canada)

2016-03-15

We have developed a passive 350 GHz (850 μm) video-camera to demonstrate lumped element kinetic inductance detectors (LEKIDs)—designed originally for far-infrared astronomy—as an option for general purpose terrestrial terahertz imaging applications. The camera currently operates at a quasi-video frame rate of 2 Hz with a noise equivalent temperature difference per frame of ∼0.1 K, which is close to the background limit. The 152 element superconducting LEKID array is fabricated from a simple 40 nm aluminum film on a silicon dielectric substrate and is read out through a single microwave feedline with a cryogenic low noise amplifier and room temperature frequency domain multiplexing electronics.

A passive terahertz video camera based on lumped element kinetic inductance detectors

International Nuclear Information System (INIS)

Rowe, Sam; Pascale, Enzo; Doyle, Simon; Dunscombe, Chris; Hargrave, Peter; Papageorgio, Andreas; Ade, Peter A. R.; Barry, Peter; Bideaud, Aurélien; Brien, Tom; Dodd, Chris; House, Julian; Moseley, Paul; Sudiwala, Rashmi; Tucker, Carole; Walker, Ian; Wood, Ken; Grainger, William; Mauskopf, Philip; Spencer, Locke

2016-01-01

We have developed a passive 350 GHz (850 μm) video-camera to demonstrate lumped element kinetic inductance detectors (LEKIDs)—designed originally for far-infrared astronomy—as an option for general purpose terrestrial terahertz imaging applications. The camera currently operates at a quasi-video frame rate of 2 Hz with a noise equivalent temperature difference per frame of ∼0.1 K, which is close to the background limit. The 152 element superconducting LEKID array is fabricated from a simple 40 nm aluminum film on a silicon dielectric substrate and is read out through a single microwave feedline with a cryogenic low noise amplifier and room temperature frequency domain multiplexing electronics.

Analysis of stability and bifurcations of fixed points and periodic solutions of a lumped model of neocortex with two delays

NARCIS (Netherlands)

Visser, Sid; Meijer, Hil G.E.; van Putten, Michel J.A.M.; van Gils, Stephan A.

2012-01-01

A lumped model of neural activity in neocortex is studied to identify regions of multi-stability of both steady states and periodic solutions. Presence of both steady states and periodic solutions is considered to correspond with epileptogenesis. The model, which consists of two delay differential

Optimization of the key geological target parameters of shale-gas horizontal wells in the Changning Block, Sichuan Basin

Directory of Open Access Journals (Sweden)

Hongzhi Yang

2016-12-01

Full Text Available In recent years, great progress has been made in geologic evaluation, engineering test and development optimization of the Lower Cambrian Wufeng Fm–Lower Silurian Longmaxi Fm shale gas in the Sichuan Basin, and the main shale gas exploitation technologies have been understood preliminarily. In addition, scale productivity construction has been completed in Jiaoshiba, Changning and Weiyuan blocks. In this paper, the Wufeng Fm–Longmaxi Fm shale gas wells in Changning Block were taken as the study object to provide technical reference for the development design of similar shale-gas horizontal wells. The technology combining geology with engineering, dynamic with static, and statistical analysis with simulation prediction was applied to quantify the main factors controlling shale-gas well productivity, develop the shale-gas well production prediction model, and optimize the key technical parameters of geologic target of shale-gas horizontal wells in the block (e.g. roadway orientation, location and spacing, horizontal section length and gas well production index. In order to realize high productivity of shale gas wells, it is necessary to maximize the included angle between the horizontal section orientation and the maximum major stress and fracture development direction, deploy horizontal-well roadway in top-quality shale layers, and drill the horizontal section in type I reservoirs over 1000 m long. It is concluded that high productivity of shale gas wells is guaranteed by the horizontal-well wellbore integrity and the optimized low-viscosity slickwater and ceramsite fracturing technology for complex fracture creation. Based on the research results, the technical policies for shale gas development of Changning Block are prepared and a guidance and reference are provided for the shale gas development and productivity construction in the block and the development design of similar shale-gas horizontal wells.

On the time-stepping stability of continuous mass-lumped and discontinuous Galerkin finite elements for the 3D acoustic wave equation

NARCIS (Netherlands)

Zhebel, E.; Minisini, S.; Mulder, W.A.

2012-01-01

We solve the three-dimensional acoustic wave equation, discretized on tetrahedral meshes. Two methods are considered: mass-lumped continuous finite elements and the symmetric interior-penalty discontinuous Galerkin method (SIP-DG). Combining the spatial discretization with the leap-frog

A comparative study of gas-gas miscibility processes in underground gas storage reservoirs

Energy Technology Data Exchange (ETDEWEB)

Rafiee, M.M.; Schmitz, S. [DBI - Gastechnologisches Institut gGmbH, Freiberg (Germany)

2013-08-01

Intermixture of gases in underground gas reservoirs have had great weight for natural gas storage in UGS projects with substitution of cushion gas by inert gases or changing the stored gas quality or origin, as for the replacement of town gas by natural gas. It was also investigated during the last years for Enhanced Gas Recovery (EGR) and Carbon Capture and Storage (CCS) projects. The actual importance of its mechanisms is discussed for the H{sub 2} storage in Power to Gas to Power projects (PGP). In these approaches miscibility of the injected gas with the gas in place in the reservoir plays an important role in the displacement process. The conditions and parameters for the gas-gas displacement and mixing have been investigated in previous projects, as e.g. the miscibility of CO{sub 2} with natural gas (CLEAN). Furthermore the miscibility process of town gas with natural gas and sauer gas with sweet gas were also previously measured and compared in laboratory. The objective of this work is to investigate the miscibility of H{sub 2} injection into natural gas reservoirs using a compositional and a black oil reservoir simulator. Three processes of convection, dispersion and diffusion are considered precisely. The effect of gas miscibility is studied for both simulators and the results are compared to find optimum miscibility parameters. The findings of this work could be helpful for further pilot and field case studies to predict and monitor the changes in gas composition and quality. In future this monitoring might become more important when PGP together with H{sub 2}-UGS, as storage technology, will help to successfully implement the change to an energy supply from more renewable sources. Similarly the method confirms the use of the black oil simulator as an alternative for gas-gas displacement and sequestration reservoir simulation in comparison to the compositional simulator. (orig.)

Gas Composition Sensor for Natural Gas and Biogas

NARCIS (Netherlands)

Boersma, A.; Sweelsen, J.; Blokland, H.

2016-01-01

The calorific value of energetic gasses is an important parameter in the quality assessment of gas steams, and can be calculated from the chemical composition of the gas. An array of capacitive sensor electrodes was developed, each functionalized with a gas responsive coating to measure the

TURTLE with MAD input (Trace Unlimited Rays Through Lumped Elements) -- A computer program for simulating charged particle beam transport systems and DECAY TURTLE including decay calculations

Energy Technology Data Exchange (ETDEWEB)

Carey, D.C.

1999-12-09

TURTLE is a computer program useful for determining many characteristics of a particle beam once an initial design has been achieved, Charged particle beams are usually designed by adjusting various beam line parameters to obtain desired values of certain elements of a transfer or beam matrix. Such beam line parameters may describe certain magnetic fields and their gradients, lengths and shapes of magnets, spacings between magnetic elements, or the initial beam accepted into the system. For such purposes one typically employs a matrix multiplication and fitting program such as TRANSPORT. TURTLE is designed to be used after TRANSPORT. For convenience of the user, the input formats of the two programs have been made compatible. The use of TURTLE should be restricted to beams with small phase space. The lumped element approximation, described below, precludes the inclusion of the effect of conventional local geometric aberrations (due to large phase space) or fourth and higher order. A reading of the discussion below will indicate clearly the exact uses and limitations of the approach taken in TURTLE.

TURTLE with MAD input (Trace Unlimited Rays Through Lumped Elements) -- A computer program for simulating charged particle beam transport systems and DECAY TURTLE including decay calculations

International Nuclear Information System (INIS)

Carey, D.C.

1999-01-01

TURTLE is a computer program useful for determining many characteristics of a particle beam once an initial design has been achieved, Charged particle beams are usually designed by adjusting various beam line parameters to obtain desired values of certain elements of a transfer or beam matrix. Such beam line parameters may describe certain magnetic fields and their gradients, lengths and shapes of magnets, spacings between magnetic elements, or the initial beam accepted into the system. For such purposes one typically employs a matrix multiplication and fitting program such as TRANSPORT. TURTLE is designed to be used after TRANSPORT. For convenience of the user, the input formats of the two programs have been made compatible. The use of TURTLE should be restricted to beams with small phase space. The lumped element approximation, described below, precludes the inclusion of the effect of conventional local geometric aberrations (due to large phase space) or fourth and higher order. A reading of the discussion below will indicate clearly the exact uses and limitations of the approach taken in TURTLE

Beyond the SCS-CN method: A theoretical framework for spatially lumped rainfall-runoff response

Science.gov (United States)

Bartlett, M. S.; Parolari, A. J.; McDonnell, J. J.; Porporato, A.

2016-06-01

Since its introduction in 1954, the Soil Conservation Service curve number (SCS-CN) method has become the standard tool, in practice, for estimating an event-based rainfall-runoff response. However, because of its empirical origins, the SCS-CN method is restricted to certain geographic regions and land use types. Moreover, it does not describe the spatial variability of runoff. To move beyond these limitations, we present a new theoretical framework for spatially lumped, event-based rainfall-runoff modeling. In this framework, we describe the spatially lumped runoff model as a point description of runoff that is upscaled to a watershed area based on probability distributions that are representative of watershed heterogeneities. The framework accommodates different runoff concepts and distributions of heterogeneities, and in doing so, it provides an implicit spatial description of runoff variability. Heterogeneity in storage capacity and soil moisture are the basis for upscaling a point runoff response and linking ecohydrological processes to runoff modeling. For the framework, we consider two different runoff responses for fractions of the watershed area: "prethreshold" and "threshold-excess" runoff. These occur before and after infiltration exceeds a storage capacity threshold. Our application of the framework results in a new model (called SCS-CNx) that extends the SCS-CN method with the prethreshold and threshold-excess runoff mechanisms and an implicit spatial description of runoff. We show proof of concept in four forested watersheds and further that the resulting model may better represent geographic regions and site types that previously have been beyond the scope of the traditional SCS-CN method.

Soil-gas phase transport and structure parameters for soils under different management regimes and at two moisture levels

DEFF Research Database (Denmark)

Eden, Marie; Møldrup, Per; Schjønning, Per

2012-01-01

Measurements of diffusive and convective gas transport parameters can be used to describe soil functional architecture and reveal key factors for soil structure development. Undisturbed 100-cm(3) soil samples were sampled at the Long-term Research on Agricultural Systems experiment located...... displayed markedly lower D-P/D-0 values at similar air-filled porosity, illustrating soil structure effects on D-P/D-0. The Currie tortuosity-connectivity parameter, X=Log(D-P/D-0)/Log(epsilon), decreased with increasing bulk density in the intact samples at both moisture conditions, suggesting less...

Analysis of Kinetic Parameter Effect on Reactor Operation Stability of the RSG-GAS Reactor

International Nuclear Information System (INIS)

Rokhmadi

2007-01-01

Kinetic parameter has influence to behaviour on RSG-GAS reactor operation. In this paper done is the calculation of reactivity curve, period-reactivity relation and low power transfer function in silicide fuel. This parameters is necessary and useful for reactivity characteristic analysis and reactor stability. To know the reactivity response, it was done reactivity insertion at power 1 watt using POKDYN code because at this level of power no feedback reactivity so important for reactor operation safety. The result of calculation showed that there is no change of significant a period-reactivity relation and transfer function at low power for 2.96 gU/cc, 3.55 gU/cc and 4.8 gU/cc density of silicide fuels. The result of the transfer function at low power showed that the reactor is critical stability with no feedback. The result of calculation also showed that reactivity response no change among three kinds of fuel densities. It can be concluded that from kinetic parameter point of view period-reactivity relation, transfer function at low power, and reactivity response are no change reactor operation from reactivity effect when fuel exchanged. (author)

The Effect of Monensin or Protexin on Gas Production Parameters of Alfalfa and Barley in the Ruminal Fungi Culture

Directory of Open Access Journals (Sweden)

saeid sobhanirad

2016-11-01

Full Text Available Introduction Since the legislation of European Union has prohibited the use of growth-promoting antibiotics such as: monensin, there is an interest in alternatives to manipulate the rumen fermentation. The use of growth-promoting antibiotics in animal feeds is banned in Europe due to having potential risks such as the spread of antibiotic resistance genes or the contamination of milk or meat with antibiotic residues. Recently, probiotics have been increasingly evaluated to replace or facilitate reductions in the use of antibiotics. Thus, the aim of this study was investigating the comparison of antibiotic (sodium monensin and probiotic (protexin on the gas production parameters and organic matter digestibility of feedstuffs (alfalfa hay, barley grain, and alfalfa+ barley mixture Materials and Methods Experimental treatments were included control (basal feeds without additive, basal feeds supplemented with sodium monensin or protexin probiotic at levels of 500 or 1000 mg per kg of DM in a rumen fungi culture. Ruminal fluid was collected from two fistulated sheep (49.5±2.5 kg and all samples were withdrawn 2 h after the morning ration had been consumed. Collected ruminal contents were strained through four layers of cheesecloth and brought immediately to the laboratory. To have a pure ruminal fungi culture, whole ruminal fluid was centrifuged at 1000 g for 10 min and added 0.100 mg/ml antibacterial agent (streptomycin sulfate, penicillin G, and chloramphenicol (14, 35. Gas production technique was used to detect the fermentation parameters of the treatments (16.Three parallel syringes of each treatment were prepared in this experiment. To measure the total gas production (A and the rate of gas production (c, cumulative gas production, organic digestibility and metabolizable energy of treatments until 120 h. Gas production was measured directly from the volume of the syringes at 0, 3, 6, 16, 24, 48, 72, 96, and 120 h. Statistical analysis of data

The Effect of Water Stress on the Gas Exchange Parameters, Productivity and Seed Health of Buckwheat (Fagopyrum esculentum Moench

Directory of Open Access Journals (Sweden)

Agnieszka Pszczółkowska

2012-12-01

Full Text Available The present pot experiment studied the effect of different soil moisture contents (60 - 70% CWC (capillary water capacity - control; 30 - 35% CWC - water stress on buckwheat productivity, the gas exchange parameters and health of buckwheat nuts. It was found that water deficit affected adversely certain biometric features investigated (plant height, number of nuts per cluster and caused a decrease in seed weight per plant. It was also shown that water stress reduced the values of the investigated gas exchange parameters (photosynthesis rate, transpiration rate, intercellular-space CO2 concentration, and stomatal conductance relative to the control treatment. Different soil moisture contents did not have a clear effect on fungal colonization of seeds. The multiplex PCR assays did not enable the detection of the genes responsible for mycotoxin synthesis. Under water deficit conditions, an increase was found in the content of albumin and globulin fractions as well as of glutelin fractions.

Changes in the basic experimental parameters of capillary gas chromatography in the 20th century.

Science.gov (United States)

Berezkin, V G; Viktorova, E N

2003-01-24

Studies of qualitative changes in capillary gas chromatography are of significant practical and scientific interest. This paper analyzes the evolution of the most important experimental chromatographic parameters over the last three decades and is based on the use of a new approach to scientometrical research that is referred to as applied scientometry. One essential feature of this approach is that it looks at the entire contents of each paper rather than only taking account its title, abstract. and references (as is typical for conventional scientometry). In this paper, we monitor how the most important chromatographic parameters, such as column length and diameter, layer thickness, stationary liquid phases, separation temperature mode. etc., have been evolving over the period 1970-2000. We used data from the following journals: Chromatographia, Journal of Chromatography, and Journal of High Resolution Chromatography and Chromatography Communications.

Quantum Monte Carlo calculation of the Fermi-liquid parameters in the two-dimensional electron gas

International Nuclear Information System (INIS)

Kwon, Y.; Ceperley, D.M.; Martin, R.M.

1994-01-01

Excitations of the two-dimensional electron gas, including many-body effects, are calculated with a variational Monte Carlo method. Correlated sampling is introduced to calculate small energy differences between different excitations. The usual pair-product (Slater-Jastrow) trial wave function is found to lack certain correlations entirely so that backflow correlation is crucial. From the excitation energies calculated here, we determine Fermi-liquid parameters and related physical quantities such as the effective mass and the Lande g factor of the system. Our results for the effective mass are compared with previous analytic calculations

Effect of process parameters on power requirements of vacuum swing adsorption technology for CO2 capture from flue gas

International Nuclear Information System (INIS)

Zhang, Jun; Webley, Paul A.; Xiao, Penny

2008-01-01

This study focuses on the effects of process and operating parameters - feed gas temperature, evacuation pressure and feed concentration - on the performance of carbon dioxide vacuum swing adsorption (CO 2 VSA) processes for CO 2 capture from gas, especially as it affects power consumption. To obtain reliable data on the VSA process, experimental work was conducted on a purposely built three bed CO 2 VSA pilot plant using commercial 13X zeolite. Both 6 step and 9 step cycles were used to determine the influences of temperature, evacuation pressure and feed concentration on process performance (recovery, purity, power and corresponding capture cost). A simple economic model for CO 2 capture was developed and employed herein. Through experiments and analysis, it is found that the feed gas temperature, evacuation pressure and feed concentration have significant effects on power consumption and CO 2 capture cost. Our data demonstrate that the CO 2 VSA process has good recovery (>70%), purity (>90%) and low power cost (4-10 kW/TPDc) when operating with 40 C feed gas provided relatively deep vacuum is used. Enhanced performance is obtained when higher feed gas concentration is fed to the plant, as expected. Our data indicates large potential for application of CO 2 VSA to CO 2 capture from flue gas. (author)

New gas turbine technology 2012-2014 - Gas Turbine Developments

Energy Technology Data Exchange (ETDEWEB)

Genrup, Magnus; Thern, Marcus [LTH, Lund (Sweden)

2013-03-15

an important verification that the plant fulfills the expectations. One important thing, however, is not to accept the test uncertainty as a test tolerance since it will provide the manufacturer overwhelming and unfair odds. Nowadays, it is common to have a maintenance agreement at some level for risk mitigation. There are different levels of contractual services ranging from parts agreement to full coverage 'bumper-to-bumper' LTSA services. One can chose to use either the OEM or another (third party) service provider. In many cases, the financing organs or insurer requires an LTSA (or better) for risk mitigation to level the insurance cost at a reasonable level. There are ways of potentially reducing the maintenance spending and one should always avoid lumped methods with equivalent hours. The word 'lumped' is used in a sense that the two different ageing mechanisms (creep, oxidation, regular wear and tear and stresses related to thermal gradients during start and stop) are evaluated as equivalent time by e.g. assuming that a start consumes time rather being a low cycle. A competent monitoring system can be a good investment - even if only a single failure can be avoided. The total world-wide gas turbine fleet is in the order of 47 000 units and the total value of the gas turbine after market was 2009 13.8 BEuro (13.8x10{sup 9} Euro). The after-market is, indeed, valuable to the manufacturers since all 47 000 units requires maintenance on a regular basis. Certain in-house produced parts may be offered with several hundred percent's margin - in contrast to about ten percent for a complete new turn-key power plant. The reward for the user, by having a LTSA, is discounted parts and prioritized treatment by the supplier. The combined cycle has about half the carbon dioxide emission compared to a coal fired plant. The large difference is driven by the higher efficiency and the higher hydrogen content in natural gas. This in combination with the

Natural gas pricing

International Nuclear Information System (INIS)

Freedenthal, C.

1993-01-01

Natural gas pricing is the heart and soul of the gas business. Price specifically affects every phase of the industry. Too low a price will result in short supplies as seen in the mid-1970s when natural gas was scarce and in tight supply. To fully understand the pricing of this energy commodity, it is important to understand the total energy picture. In addition, the effect and impact of world and US economies, and economics in general are crucial to understanding natural gas pricing. The purpose of this presentation will be to show the parameters going into US natural gas pricing including the influence of the many outside industry factors like crude oil and coal pricing, market drivers pushing the gas industry, supply/demand parameters, risk management for buyers and sellers, and other elements involved in pricing analysis

Finding and testing network communities by lumped Markov chains.

Science.gov (United States)

Piccardi, Carlo

2011-01-01

Identifying communities (or clusters), namely groups of nodes with comparatively strong internal connectivity, is a fundamental task for deeply understanding the structure and function of a network. Yet, there is a lack of formal criteria for defining communities and for testing their significance. We propose a sharp definition that is based on a quality threshold. By means of a lumped Markov chain model of a random walker, a quality measure called "persistence probability" is associated to a cluster, which is then defined as an "α-community" if such a probability is not smaller than α. Consistently, a partition composed of α-communities is an "α-partition." These definitions turn out to be very effective for finding and testing communities. If a set of candidate partitions is available, setting the desired α-level allows one to immediately select the α-partition with the finest decomposition. Simultaneously, the persistence probabilities quantify the quality of each single community. Given its ability in individually assessing each single cluster, this approach can also disclose single well-defined communities even in networks that overall do not possess a definite clusterized structure.

Finding and testing network communities by lumped Markov chains.

Directory of Open Access Journals (Sweden)

Carlo Piccardi

Full Text Available Identifying communities (or clusters, namely groups of nodes with comparatively strong internal connectivity, is a fundamental task for deeply understanding the structure and function of a network. Yet, there is a lack of formal criteria for defining communities and for testing their significance. We propose a sharp definition that is based on a quality threshold. By means of a lumped Markov chain model of a random walker, a quality measure called "persistence probability" is associated to a cluster, which is then defined as an "α-community" if such a probability is not smaller than α. Consistently, a partition composed of α-communities is an "α-partition." These definitions turn out to be very effective for finding and testing communities. If a set of candidate partitions is available, setting the desired α-level allows one to immediately select the α-partition with the finest decomposition. Simultaneously, the persistence probabilities quantify the quality of each single community. Given its ability in individually assessing each single cluster, this approach can also disclose single well-defined communities even in networks that overall do not possess a definite clusterized structure.

Impact of gas puffing location on density control and plasma parameters in TJ-II

International Nuclear Information System (INIS)

Tabares, F.L.; Garcia-Cortes, I.; Estrada, T.; Tafalla, D.; Hidalgo, A.; Ferreira, J.A.; Pastor, I.; Herranz, J.; Ascasibar, E.

2005-01-01

Under pure Electron Cyclotron Resonance Heating (ECRH) conditions in TJ-II plasmas (P<300 kW, 53.2 GHz, 2nd harmonic X-mode, power density < 25 W/m''3), plasma start-up and good density control are obtained only by the proper combination of wall conditions and gas puffing characteristics. Such a control is particularly critical for the optimisation of the NBI power transfer to the target plasmas. The relatively low cut-off limit is easily reached due not only to the unfavourable wall/puffing-fuelling ratio but also due to the steep density profiles developed during the Enhanced Particle Confinement (EPC) modes. These modes are triggered by the gas puffing waveform, and they cannot be achieved for high iota magnetic configurations in TJ-II. Comparative experiments under metallic and boronised wall conditions have shown that the sensitivity of the EPC modes to the puffing rate is at least partially related to the energy balance at the plasma periphery under central heating scenarios. In this work, the impact of gas-fuelling location on the plasma parameters and density control is described. For that purpose, three different fuelling locations have been investigated; broad distribution from a side ports, localized injection from long tubes at different poloidal positions and highly localized injection through a movable limiter. Edge density and temperature profiles from a broad set of diagnostics (atomic beams, reflectometry, Thompson Scattering ECE, etc...) are analysed and compared. It has been found that preventing from transition to the EPC mode is achieved by using slow puffing rates, while neutral penetration into the plasma core can be enhanced for highly localized gas sources. Wall inventory, however, has been found to pl ay a dominant role in the fuelling of the plasma under most conditions. (author)

Importance of physical examination in early detection of lump in breast in women of different age groups

International Nuclear Information System (INIS)

Abbas, H.; Imran, S.; Waris, Noorul-ain-Hafeez; Khanam, A.; Khurshid, R.

2010-01-01

Background: The spectrum of breast lesions in adolescents varies markedly from that for adults, with the former lesions being overwhelmingly benign. Fine needle biopsy can be used to distinguish benign and malignant tumour. Study Design: This study examined the characteristics and outcome of women with different age groups in whom physical examination was their sole method of lump in breast detection. Patients and Methods: A total of 200 patients were included in the study. These were divided into 3 groups. Group A was consisting of 75 girls with age of pubescent. Group B included 69 suspected breast cancer women with age range 26-38 years. Fifty-six suspected breast cancer women with age range 41-60 year were included as group C. Study was carried out in patients admitted in the Department/Out-door of Surgery, Sir Ganga Ram Hospital, Lahore, Pakistan. Study period was 6 months. All women received a physical examination by a breast surgeon. Proforma including demographic and clinical characteristics were filled. The diagnosis for patients in this study was achieved by core needle biopsy using a 14-gauge cutting needle. Results: It was observed that early age at menarche ( 25 may be a risk factor in peri/post menopausal women. Active life style is more important with increasing age as it decreases the risk of developing tumour state. Family history was more common in women with peri/post menopausal status as compared to other age groups. Clinical characteristics showed that lump size <2.5 cm was more common in both pubescent and reproductive age. While lump size with a range of 2.5-5.0 cm, was observed in all groups of patients. Fibroadenoma is observed in almost all women with pubescent age while both benign and malignant tumour observed in women with reproductive age. Malignant tumour was observed mostly in women with peri/post menopausal status. Conclusion: Study concluded that early detection or clinical examination with FNA cut out the patients from harassment

Compensation of the magnetization current induced sextupole error at LHC injection field by short lumped permanent sextupole magnets, incorporated into the end configuration of superconducting dipoles

CERN Document Server

Asner, A

1985-01-01

Compensation of the magnetization current induced sextupole error at LHC injection field by short lumped permanent sextupole magnets, incorporated into the end configuration of superconducting dipoles

Parameters control in GAs for dynamic optimization

Directory of Open Access Journals (Sweden)

Khalid Jebari

2013-02-01

Full Text Available The Control of Genetic Algorithms parameters allows to optimize the search process and improves the performance of the algorithm. Moreover it releases the user to dive into a game process of trial and failure to find the optimal parameters.

Distributed ESO based cooperative tracking control for high-order nonlinear multiagent systems with lumped disturbance and application in multi flight simulators systems.

Science.gov (United States)

Cong, Zhang

2018-03-01

Based on extended state observer, a novel and practical design method is developed to solve the distributed cooperative tracking problem of higher-order nonlinear multiagent systems with lumped disturbance in a fixed communication topology directed graph. The proposed method is designed to guarantee all the follower nodes ultimately and uniformly converge to the leader node with bounded residual errors. The leader node, modeled as a higher-order non-autonomous nonlinear system, acts as a command generator giving commands only to a small portion of the networked follower nodes. Extended state observer is used to estimate the local states and lumped disturbance of each follower node. Moreover, each distributed controller can work independently only requiring the relative states and/or the estimated relative states information between itself and its neighbors. Finally an engineering application of multi flight simulators systems is demonstrated to test and verify the effectiveness of the proposed algorithm. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Lithium-ion Battery Electrothermal Model, Parameter Estimation, and Simulation Environment

Directory of Open Access Journals (Sweden)

Simone Orcioni

2017-03-01

Full Text Available The market for lithium-ion batteries is growing exponentially. The performance of battery cells is growing due to improving production technology, but market request is growing even more rapidly. Modeling and characterization of single cells and an efficient simulation environment is fundamental for the development of an efficient battery management system. The present work is devoted to defining a novel lumped electrothermal circuit of a single battery cell, the extraction procedure of the parameters of the single cell from experiments, and a simulation environment in SystemC-WMS for the simulation of a battery pack. The electrothermal model of the cell was validated against experimental measurements obtained in a climatic chamber. The model is then used to simulate a 48-cell battery, allowing statistical variations among parameters. The different behaviors of the cells in terms of state of charge, current, voltage, or heat flow rate can be observed in the results of the simulation environment.

Experimental evaluation of a modal parameter based system identification procedure

Science.gov (United States)

Yu, Minli; Feng, Ningsheng; Hahn, Eric J.

2016-02-01

Correct modelling of the foundation of a rotor bearing foundation system (RBFS) is an invaluable asset for the balancing and efficient running of turbomachinery. Numerical experiments have shown that a modal parameter based identification approach could be feasible for this purpose but there is a lack of experimental verification of the suitability of such a modal approach for even the simplest systems. In this paper the approach is tested on a simple experimental rig comprising a clamped horizontal bar with lumped masses. It is shown that apart from damping, the proposed approach can identify reasonably accurately the relevant modal parameters of the rig; and that the resulting equivalent system can predict reasonably well the frequency response of the rig. Hence, the proposed approach shows promise but further testing is required, since application to identifying the foundation of an RBFS involves the additional problem of accurately obtaining the force excitation from motion measurements.

Noncommutative field gas driven inflation

Energy Technology Data Exchange (ETDEWEB)

Barosi, Luciano; Brito, Francisco A [Departamento de Fisica, Universidade Federal de Campina Grande, Caixa Postal 10071, 58109-970 Campina Grande, Paraiba (Brazil); Queiroz, Amilcar R, E-mail: lbarosi@ufcg.edu.br, E-mail: fabrito@df.ufcg.edu.br, E-mail: amilcarq@gmail.com [Centro Internacional de Fisica da Materia Condensada, Universidade de Brasilia, Caixa Postal 04667, Brasilia, DF (Brazil)

2008-04-15

We investigate early time inflationary scenarios in a Universe filled with a dilute noncommutative bosonic gas at high temperature. A noncommutative bosonic gas is a gas composed of a bosonic scalar field with noncommutative field space on a commutative spacetime. Such noncommutative field theories were recently introduced as a generalization of quantum mechanics on a noncommutative spacetime. Key features of these theories are Lorentz invariance violation and CPT violation. In the present study we use a noncommutative bosonic field theory that, besides the noncommutative parameter {theta}, shows up a further parameter {sigma}. This parameter {sigma} controls the range of the noncommutativity and acts as a regulator for the theory. Both parameters play a key role in the modified dispersion relations of the noncommutative bosonic field, leading to possible striking consequences for phenomenology. In this work we obtain an equation of state p = {omega}({sigma},{theta};{beta}){rho} for the noncommutative bosonic gas relating pressure p and energy density {rho}, in the limit of high temperature. We analyse possible behaviours for these gas parameters {sigma}, {theta} and {beta}, so that -1{<=}{omega}<-1/3, which is the region where the Universe enters an accelerated phase.

Assessment of Lumped-Parameter Models for Rigid Footings

DEFF Research Database (Denmark)

Andersen, Lars

2010-01-01

and vertical translations as well as torsion and rocking, and the necessity of coupling between horizontal sliding and rocking is discussed. Most of the analyses are carried out for hexagonal footings; but in order to generalise the conclusions to a broader variety of footings, comparisons are made...

Effect of engine parameters and type of gaseous fuel on the performance of dual-fuel gas diesel engines. A critical review

Energy Technology Data Exchange (ETDEWEB)

Sahoo, B.B. [Centre for Energy, Indian Institute of Technology, Guwahati 781039 (India); Sahoo, N.; Saha, U.K. [Department of Mechanical Engineering, Indian Institute of Technology, Guwahati 781039 (India)

2009-08-15

Petroleum resources are finite and, therefore, search for their alternative non-petroleum fuels for internal combustion engines is continuing all over the world. Moreover gases emitted by petroleum fuel driven vehicles have an adverse effect on the environment and human health. There is universal acceptance of the need to reduce such emissions. Towards this, scientists have proposed various solutions for diesel engines, one of which is the use of gaseous fuels as a supplement for liquid diesel fuel. These engines, which use conventional diesel fuel and gaseous fuel, are referred to as 'dual-fuel engines'. Natural gas and bio-derived gas appear more attractive alternative fuels for dual-fuel engines in view of their friendly environmental nature. In the gas-fumigated dual-fuel engine, the primary fuel is mixed outside the cylinder before it is inducted into the cylinder. A pilot quantity of liquid fuel is injected towards the end of the compression stroke to initiate combustion. When considering a gaseous fuel for use in existing diesel engines, a number of issues which include, the effects of engine operating and design parameters, and type of gaseous fuel, on the performance of the dual-fuel engines, are important. This paper reviews the research on above issues carried out by various scientists in different diesel engines. This paper touches upon performance, combustion and emission characteristics of dual-fuel engines which use natural gas, biogas, producer gas, methane, liquefied petroleum gas, propane, etc. as gaseous fuel. It reveals that 'dual-fuel concept' is a promising technique for controlling both NO{sub x} and soot emissions even on existing diesel engine. But, HC, CO emissions and 'bsfc' are higher for part load gas diesel engine operations. Thermal efficiency of dual-fuel engines improve either with increased engine speed, or with advanced injection timings, or with increased amount of pilot fuel. The ignition

Variations of the blood gas levels and thermodilutional parameters during ICP monitoring after severe head trauma in children.

Science.gov (United States)

Lubrano, Riccardo; Elli, Marco; Stoppa, Francesca; Di Traglia, Mario; Di Nardo, Matteo; Perrotta, Daniela; David, Piero; Paoli, Sara; Cecchetti, Corrado

2015-08-01

The purpose of this study was to define, in children following head trauma and GSC ≤ 8, at which level of intracranial pressure (ICP), the thermodilutional, and gas analytic parameters implicated in secondary cerebral insults shows initial changes. We enrolled in the study 56 patients: 30 males and 26 females, mean age 71 ± 52 months. In all children, volumetric hemodynamic and blood gas parameters were monitored following initial resuscitation and every 4 h thereafter or whenever a hemodynamic deterioration was suspected. During the cumulative hospital stay, a total of 1050 sets of measurements were done. All parameters were stratified in seven groups according to ICP (group A1 = 0-5 mmHg, group A2 = 6-10 mmHg, group A3 = 11-15 mmHg, group A4 16-20 mmHg, group A5 21-25 mmHg, group A6 26-30 mmHg, group A7 >31 mmHg). Mean values of jugular oxygen saturation (SJO2), jugular oxygen partial pressure (PJO2), extravascular lung water (EVLWi), pulmonary vascular permeability (PVPi), fluid overload (FO), and cerebral extraction of oxygen (CEO2) vary significantly from A3 (11-15 mmHg) to A4 (16-20 mmHg). They relate to ICP in a four-parameter sigmoidal function (4PS function with: r(2) = 0.90), inflection point of 15 mmHg of ICP, and a maximum curvature point on the left horizontal asymptote at 13 mmHg of ICP. Mean values of SJO2, PJO2, EVLWi, PVPi, FO, and CEO2 become pathologic at 15 mmHg of ICP; however, the curve turns steeper at 13 mmHg, possibly a warning level in children for the development of post head trauma secondary insult.

Theoretical study of inspiratory flow waveforms during mechanical ventilation on pulmonary blood flow and gas exchange.

Science.gov (United States)

Niranjan, S C; Bidani, A; Ghorbel, F; Zwischenberger, J B; Clark, J W

1999-08-01

A lumped two-compartment mathematical model of respiratory mechanics incorporating gas exchange and pulmonary circulation is utilized to analyze the effects of square, descending and ascending inspiratory flow waveforms during mechanical ventilation. The effects on alveolar volume variation, alveolar pressure, airway pressure, gas exchange rate, and expired gas species concentration are evaluated. Advantages in ventilation employing a certain inspiratory flow profile are offset by corresponding reduction in perfusion rates, leading to marginal effects on net gas exchange rates. The descending profile provides better CO2 exchange, whereas the ascending profile is more advantageous for O2 exchange. Regional disparities in airway/lung properties create maldistribution of ventilation and a concomitant inequality in regional alveolar gas composition and gas exchange rates. When minute ventilation is maintained constant, for identical time constant disparities, inequalities in compliance yield pronounced effects on net gas exchange rates at low frequencies, whereas the adverse effects of inequalities in resistance are more pronounced at higher frequencies. Reduction in expiratory air flow (via increased airway resistance) reduces the magnitude of upstroke slope of capnogram and oxigram time courses without significantly affecting end-tidal expired gas compositions, whereas alterations in mechanical factors that result in increased gas exchanges rates yield increases in CO2 and decreases in O2 end-tidal composition values. The model provides a template for assessing the dynamics of cardiopulmonary interactions during mechanical ventilation by combining concurrent descriptions of ventilation, capillary perfusion, and gas exchange. Copyright 1999 Academic Press.

41 CFR 301-11.638 - May we offer a lump sum payment to cover the income tax liability on the covered ITRA?

Science.gov (United States)

2010-07-01

... payment to cover the income tax liability on the covered ITRA? 301-11.638 Section 301-11.638 Public... Thereafter Agency Responsibilities § 301-11.638 May we offer a lump sum payment to cover the income tax... understands that he/she is responsible for any income taxes without further reimbursement. See the...

41 CFR 301-11.538 - May we offer a lump sum payment to cover the income tax liability on the covered ITRA?

Science.gov (United States)

2010-07-01

... payment to cover the income tax liability on the covered ITRA? 301-11.538 Section 301-11.538 Public... 1994 Agency Responsibilities § 301-11.538 May we offer a lump sum payment to cover the income tax... understands that he/she is responsible for any income taxes without further reimbursement. (See the...

Mass and Heat Transfer Analysis of Membrane Humidifier with a Simple Lumped Mass Model

International Nuclear Information System (INIS)

Lee, Young Duk; Bae, Ho June; Ahn, Kook Young; Yu, Sang Seok; Hwang, Joon Young

2009-01-01

The performance of proton exchange membrane fuel cell (PEMFC) is seriously changed by the humidification condition which is intrinsic characteristics of the PEMFC. Typically, the humidification of fuel cell is carried out with internal or external humidifier. A membrane humidifier is applied to the external humidification of residential power generation fuel cell due to its convenience and high performance. In this study, a simple static model is constructed to understand the physical phenomena of the membrane humidifier in terms of geometric parameters and operating parameters. The model utilizes the concept of shell and tube heat exchanger but the model is also able to estimate the mass transport through the membrane. Model is constructed with FORTRAN under Matlab/Simulink □ environment to keep consistency with other components model which we already developed. Results shows that the humidity of wet gas and membrane thickness are critical parameters to improve the performance of the humidifier

Union Gas and Ontario gas production

International Nuclear Information System (INIS)

Cameron, C.

2001-01-01

A step-by-step review of the tie-in process of new production wells into the Union Gas System is described. Requirements of the producer and those of Union Gas are explained. Also described are the choices available to the producer to sell his gas. He can sell either to Union Gas directly at an agreed upon price, or the producer has the option to have what is called an M13 contract which allows him to sell his gas at Dawn, where it can be stored within parameters of the contract, and sold to any buyer at Dawn at a negotiated rate. This arrangement, while entailing a much greater administrative load than direct sale to Union Gas, nevertheless, allows the producer to take advantage of market fluctuations. A third option provided by Union Gas is to make available to the producer storage space greater than the provisions of the M13 contract at current market rate, thereby opening up the opportunity to the producer to capture additional value in later winter months (when gas is in greater demand)

Polymeric membrane materials: new aspects of empirical approaches to prediction of gas permeability parameters in relation to permanent gases, linear lower hydrocarbons and some toxic gases.

Science.gov (United States)

Malykh, O V; Golub, A Yu; Teplyakov, V V

2011-05-11

Membrane gas separation technologies (air separation, hydrogen recovery from dehydrogenation processes, etc.) use traditionally the glassy polymer membranes with dominating permeability of "small" gas molecules. For this purposes the membranes based on the low free volume glassy polymers (e.g., polysulfone, tetrabromopolycarbonate and polyimides) are used. On the other hand, an application of membrane methods for VOCs and some toxic gas recovery from air, separation of the lower hydrocarbons containing mixtures (in petrochemistry and oil refining) needs the membranes with preferable penetration of components with relatively larger molecular sizes. In general, this kind of permeability is characterized for rubbers and for the high free volume glassy polymers. Data files accumulated (more than 1500 polymeric materials) represent the region of parameters "inside" of these "boundaries." Two main approaches to the prediction of gas permeability of polymers are considered in this paper: (1) the statistical treatment of published transport parameters of polymers and (2) the prediction using model of ≪diffusion jump≫ with consideration of the key properties of the diffusing molecule and polymeric matrix. In the frames of (1) the paper presents N-dimensional methods of the gas permeability estimation of polymers using the correlations "selectivity/permeability." It is found that the optimal accuracy of prediction is provided at n=4. In the frames of the solution-diffusion mechanism (2) the key properties include the effective molecular cross-section of penetrating species to be responsible for molecular transportation in polymeric matrix and the well known force constant (ε/k)(eff i) of {6-12} potential for gas-gas interaction. Set of corrected effective molecular cross-section of penetrant including noble gases (He, Ne, Ar, Kr, Xe), permanent gases (H(2), O(2), N(2), CO), ballast and toxic gases (CO(2), NO(,) NO(2), SO(2), H(2)S) and linear lower hydrocarbons (CH(4

Ideal-gas thermodynamic properties for natural-gas applications

International Nuclear Information System (INIS)

Jaeschke, M.; Schley, P.

1995-01-01

Calculating caloric properties from a thermal equation of state requires information such as isobaric heat capacities in the ideal-gas state as a function of temperature. In this work, values for the parameters of the c p o correlation proposed by Aly and Lee were newly determined for 21 pure gases which are compounds of natural gas mixtures. The values of the parameters were adjusted to selected c p o data calculated form spectroscopic data for temperatures ranging from 10 to 1000 K. The data sources used are discussed and compared with literature data deduced from theoretic models and caloric measurements. The parameters presented will be applied in a current GERG project for evaluating equations of state (e.g., the AGA 8 equation) for their suitability for calculating caloric properties

Effect of adjuvant noninvasive positive pressure ventilation on blood gas parameters, cardiac function and inflammatory state in patients with COPD and type II respiratory failure

Directory of Open Access Journals (Sweden)

You-Ming Zhu1

2017-03-01

Full Text Available Objective: T o analyze the effect of adjuvant noninvasive positive pressure ventilation on blood gas parameters, cardiac function and inflammatory state in patients with chronic obstructive pulmonary disease (COPD and type II respiratory failure. Methods: 90 patients with COPD and type II respiratory failure were randomly divided into observation group and control group (n=45. Control group received conventional therapy, observation group received conventional therapy + adjuvant noninvasive positive pressure ventilation, and differences in blood gas parameters, cardiac function, inflammatory state, etc., were compared between two groups of patients 2 weeks after treatment. Results: Arterial blood gas parameters pH and alveolar-arterial partial pressure of oxygen [P(A-aO2] levels of observation group were higher than those of control group while, potassium ion (K+, chloride ion (Cl﹣ and carbon dioxide combining power (CO2CP levels were lower than those of control group 2 weeks after treatment; echocardiography parameters Doppler-derived tricuspid lateral annular systolic velocity (DTIS and pulmonary arterial velocity (PAV levels were lower than those of control group (P＜0.05 while pulmonary artery accelerating time (PAACT, left ventricular enddiastolic dimension (LVDd and right atrioventricular tricuspid annular plane systolic excursion (TAPSE levels were higher than those of control group (P＜0.05; serum cardiac function indexes adiponectin (APN, Copeptin, N-terminal pro-B-type natriuretic peptide (NT-proBNP, cystatin C (CysC, growth differentiation factor-15 (GDF-15 and heart type fatty acid binding protein (H-FABP content were lower than those of control group (P＜0.05; serum inflammatory factors hypersensitive C-reactive protein (hs-CRP, tumor necrosis factor-α (TNF-α, interleukin-1β (IL-1β, IL-8, IL-10, and transforming growth factor-β1 (TGF-β1 content were lower than those of control group (P＜0.05. Conclusions: Adjuvant

Determination of the solubility parameter of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate by inverse gas chromatography.

Science.gov (United States)

Ma, Xiaohong; Wang, Qiang; Li, Xiaoping; Tang, Jun; Zhang, Zhengfang

2015-11-01

Thermodynamic properties of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM] BF4) were determined via inverse gas chromatography (IGC). Two groups of solvents with different chemical natures and polarities were used to obtain information about [BMIM] BF4-solvent interactions. The specific retention volume, molar heat of sorption, weight fraction activity coefficient, Flory-Huggins interaction parameter as well as solubility parameter were also determined in a temperature range of 333 - 373 K. The results showed that the selected solvents n-C10 to n-C12, carbon tetrachloride, cyclohexane and toluene were poor solvents for [BMIM] BF4, while dichloromethane, acetone, chloroform, methyl acetate, ethanol and methanol were favorite solvents for [BMIM] BF4. In addition, the solubility parameter of [ BMIM] BF4 was determined as 23.39 (J/cm3)0.5 by the extrapolation at 298 K. The experiment proved that IGC was a simple and accurate method to obtain the thermodynamic properties of ionic liquids. This study could be used as a reference to the application and research of the ionic liquids.

Correlation of 210Po implanted in glass with radon gas exposure: sensitivity analysis of critical parameters using a Monte-Carlo approach.

Science.gov (United States)

Walsh, C; McLaughlin, J P

2001-05-14

In recent years, 210Po implanted in glass artefacts has been used as an indicator of the mean radon gas concentration in dwellings in the past. Glass artefacts have been selected in many dwellings and the alpha-recoil implanted 210Po concentration has been measured using various techniques. Some of these retrospective techniques use a model to estimate the retrospective radon gas on the basis of this surface 210Po activity. The accumulation of 210Po on glass surfaces is determined by the deposition regime over the exposure period. The 210Po activity is determined not only by the radon progeny deposition velocities, but by other room parameters such as ventilation rate, aerosol conditions and the surface to volume ratio of the room. Up to now in using room models, a nominal or 'base-case' scenario is used, i.e. a single value is chosen for each input parameter. In this paper a Monte-Carlo analysis is presented in which a probability distribution for each parameter is chosen, based on measurements quoted in the literature. A 210Po surface activity is calculated using a single value drawn from each of the parameter distributions using a pseudo-random number generator. This process is repeated n times (up to 20,000), producing n independent scenarios with corresponding 210Po values. This process permits a sensitivity analysis to be carried out to see the effect of changes in inputs on the model output.

Life-cycle greenhouse gas emissions of shale gas, natural gas, coal, and petroleum.

Science.gov (United States)

Burnham, Andrew; Han, Jeongwoo; Clark, Corrie E; Wang, Michael; Dunn, Jennifer B; Palou-Rivera, Ignasi

2012-01-17

The technologies and practices that have enabled the recent boom in shale gas production have also brought attention to the environmental impacts of its use. It has been debated whether the fugitive methane emissions during natural gas production and transmission outweigh the lower carbon dioxide emissions during combustion when compared to coal and petroleum. Using the current state of knowledge of methane emissions from shale gas, conventional natural gas, coal, and petroleum, we estimated up-to-date life-cycle greenhouse gas emissions. In addition, we developed distribution functions for key parameters in each pathway to examine uncertainty and identify data gaps such as methane emissions from shale gas well completions and conventional natural gas liquid unloadings that need to be further addressed. Our base case results show that shale gas life-cycle emissions are 6% lower than conventional natural gas, 23% lower than gasoline, and 33% lower than coal. However, the range in values for shale and conventional gas overlap, so there is a statistical uncertainty whether shale gas emissions are indeed lower than conventional gas. Moreover, this life-cycle analysis, among other work in this area, provides insight on critical stages that the natural gas industry and government agencies can work together on to reduce the greenhouse gas footprint of natural gas.

Assessing the Effects of Water Deficit on Photosynthesis Using Parameters Derived from Measurements of Leaf Gas Exchange and of Chlorophyll a Fluorescence.

Science.gov (United States)

Urban, Laurent; Aarrouf, Jawad; Bidel, Luc P R

2017-01-01

Water deficit (WD) is expected to increase in intensity, frequency and duration in many parts of the world as a consequence of global change, with potential negative effects on plant gas exchange and growth. We review here the parameters that can be derived from measurements made on leaves, in the field, and that can be used to assess the effects of WD on the components of plant photosynthetic rate, including stomatal conductance, mesophyll conductance, photosynthetic capacity, light absorbance, and efficiency of absorbed light conversion into photosynthetic electron transport. We also review some of the parameters related to dissipation of excess energy and to rerouting of electron fluxes. Our focus is mainly on the techniques of gas exchange measurements and of measurements of chlorophyll a fluorescence (ChlF), either alone or combined. But we put also emphasis on some of the parameters derived from analysis of the induction phase of maximal ChlF, notably because they could be used to assess damage to photosystem II. Eventually we briefly present the non-destructive methods based on the ChlF excitation ratio method which can be used to evaluate non-destructively leaf contents in anthocyanins and flavonols.

Assessing the Effects of Water Deficit on Photosynthesis Using Parameters Derived from Measurements of Leaf Gas Exchange and of Chlorophyll a Fluorescence

Directory of Open Access Journals (Sweden)

Laurent Urban

2017-12-01

Full Text Available Water deficit (WD is expected to increase in intensity, frequency and duration in many parts of the world as a consequence of global change, with potential negative effects on plant gas exchange and growth. We review here the parameters that can be derived from measurements made on leaves, in the field, and that can be used to assess the effects of WD on the components of plant photosynthetic rate, including stomatal conductance, mesophyll conductance, photosynthetic capacity, light absorbance, and efficiency of absorbed light conversion into photosynthetic electron transport. We also review some of the parameters related to dissipation of excess energy and to rerouting of electron fluxes. Our focus is mainly on the techniques of gas exchange measurements and of measurements of chlorophyll a fluorescence (ChlF, either alone or combined. But we put also emphasis on some of the parameters derived from analysis of the induction phase of maximal ChlF, notably because they could be used to assess damage to photosystem II. Eventually we briefly present the non-destructive methods based on the ChlF excitation ratio method which can be used to evaluate non-destructively leaf contents in anthocyanins and flavonols.

Mathematical modeling of non-stationary gas flow in gas pipeline

Science.gov (United States)

Fetisov, V. G.; Nikolaev, A. K.; Lykov, Y. V.; Duchnevich, L. N.

2018-03-01

An analysis of the operation of the gas transportation system shows that for a considerable part of time pipelines operate in an unsettled regime of gas movement. Its pressure and flow rate vary along the length of pipeline and over time as a result of uneven consumption and selection, switching on and off compressor units, shutting off stop valves, emergence of emergency leaks. The operational management of such regimes is associated with difficulty of reconciling the operating modes of individual sections of gas pipeline with each other, as well as with compressor stations. Determining the grounds that cause change in the operating mode of the pipeline system and revealing patterns of these changes determine the choice of its parameters. Therefore, knowledge of the laws of changing the main technological parameters of gas pumping through pipelines in conditions of non-stationary motion is of great importance for practice.

Synergistic improvement of gas sensing performance by micro-gravimetrically extracted kinetic/thermodynamic parameters

International Nuclear Information System (INIS)

Guo, Shuanbao; Xu, Pengcheng; Yu, Haitao; Cheng, Zhenxing; Li, Xinxin

2015-01-01

Highlights: • Sensing material can be comprehensively optimized by using gravimetric cantilever. • Kinetic-thermodynamic model parameters are quantitatively extracted by experiment • Sensing-material performance is synergistically optimized by extracted parameters. - Abstract: A novel method is explored for comprehensive design/optimization of organophosphorus sensing material, which is loaded on mass-type microcantilever sensor. Conventionally, by directly observing the gas sensing response, it is difficult to build quantitative relationship with the intrinsic structure of the material. To break through this difficulty, resonant cantilever is employed as gravimetric tool to implement molecule adsorption experiment. Based on the sensing data, key kinetic/thermodynamic parameters of the material to the molecule, including adsorption heat −ΔH°, adsorption/desorption rate constants K a and K d , active-site number per unit mass N′ and surface coverage θ, can be quantitatively extracted according to physical–chemistry theories. With gaseous DMMP (simulant of organophosphorus agents) as sensing target, the optimization route for three sensing materials is successfully demonstrated. Firstly, a hyper-branched polymer is evaluated. Though suffering low sensitivity due to insufficient N′, the bis(4-hydroxyphenyl)-hexafluoropropane (BHPF) sensing-group exhibits satisfactory reproducibility due to appropriate −ΔH°. To achieve more sensing-sites, KIT-5 mesoporous-silica with higher surface-area is assessed, resulting in good sensitivity but too high −ΔH° that brings poor repeatability. After comprehensive consideration, the confirmed BHPF sensing-group is grafted on the KIT-5 carrier to form an optimized DMMP sensing nanomaterial. Experimental results indicate that, featuring appropriate kinetic/thermodynamic parameters of −ΔH°, K a , K d , N′ and θ, the BHPF-functionalized KIT-5 mesoporous silica exhibits synergistic improvement among

The level density parameters for fermi gas model

International Nuclear Information System (INIS)

Zuang Youxiang; Wang Cuilan; Zhou Chunmei; Su Zongdi

1986-01-01

Nuclear level densities are crucial ingredient in the statistical models, for instance, in the calculations of the widths, cross sections, emitted particle spectra, etc. for various reaction channels. In this work 667 sets of more reliable and new experimental data are adopted, which include average level spacing D D , radiative capture width Γ γ 0 at neutron binding energy and cumulative level number N 0 at the low excitation energy. They are published during 1973 to 1983. Based on the parameters given by Gilbert-Cameon and Cook the physical quantities mentioned above are calculated. The calculated results have the deviation obviously from experimental values. In order to improve the fitting, the parameters in the G-C formula are adjusted and new set of level density parameters is obsained. The parameters is this work are more suitable to fit new measurements

Computing Fault-Containment Times of Self-Stabilizing Algorithms Using Lumped Markov Chains

Directory of Open Access Journals (Sweden)

Volker Turau

2018-05-01

Full Text Available The analysis of self-stabilizing algorithms is often limited to the worst case stabilization time starting from an arbitrary state, i.e., a state resulting from a sequence of faults. Considering the fact that these algorithms are intended to provide fault tolerance in the long run, this is not the most relevant metric. A common situation is that a running system is an a legitimate state when hit by a single fault. This event has a much higher probability than multiple concurrent faults. Therefore, the worst case time to recover from a single fault is more relevant than the recovery time from a large number of faults. This paper presents techniques to derive upper bounds for the mean time to recover from a single fault for self-stabilizing algorithms based on Markov chains in combination with lumping. To illustrate the applicability of the techniques they are applied to a new self-stabilizing coloring algorithm.

Effect of Gas Tungsten Arc Welding Parameters on Hydrogen-Assisted Cracking of Type 321 Stainless Steel

Science.gov (United States)

Rozenak, Paul; Unigovski, Yaakov; Shneck, Roni

2016-05-01

The susceptibility of AISI type 321 stainless steel welded by the gas tungsten arc welding (GTAW) process to hydrogen-assisted cracking (HAC) was studied in a tensile test combined with in situ cathodic charging. Specimen charging causes a decrease in ductility of both the as-received and welded specimens. The mechanical properties of welds depend on welding parameters. For example, the ultimate tensile strength and ductility increase with growing shielding gas (argon) rate. More severe decrease in the ductility was obtained after post-weld heat treatment (PWHT). In welded steels, in addition to discontinuous grain boundary carbides (M23C6) and dense distribution of metal carbides MC ((Ti, Nb)C) precipitated in the matrix, the appearance of delta-ferrite phase was observed. The fracture of sensitized specimens was predominantly intergranular, whereas the as-welded specimens exhibited mainly transgranular regions. High-dislocation density regions and stacking faults were found in delta-ferrite formed after welding. Besides, thin stacking fault plates and epsilon-martensite were found in the austenitic matrix after the cathodic charging.

The Role of Spraying Parameters and Inert Gas Shrouding in Hybrid Water-Argon Plasma Spraying of Tungsten and Copper for Nuclear Fusion Applications

Czech Academy of Sciences Publication Activity Database

Matějíček, Jiří; Kavka, Tetyana; Bertolissi, Gabriele; Ctibor, Pavel; Vilémová, Monika; Mušálek, Radek; Nevrlá, Barbara

2013-01-01

Roč. 22, č. 5 (2013), s. 744-755 ISSN 1059-9630 R&D Projects: GA MPO FR-TI2/702; GA TA ČR TA01010300 Institutional support: RVO:61389021 Keywords : plasma spraying * tungsten * copper * inert gas shrouding * water-argon plasma torch * gas shroud * hybrid plasma torch * influence of spray parameters * nuclear fusion * oxidation Subject RIV: JG - Metallurgy Impact factor: 1.491, year: 2013 http://link.springer.com/content/pdf/10.1007%2Fs11666-013-9895-x.pdf

Assessment of blood gas parameters and the degree of inflammation in noninvasive positive pressure ventilation combined with aminophylline treatment of COPD complicated with type II respiratory failure

Directory of Open Access Journals (Sweden)

Jin-Ru Zhang

2016-10-01

Full Text Available Objective: To analyze the effect of noninvasive positive pressure ventilation combined with aminophylline therapy on blood gas parameters and the degree of inflammation in patients with COPD and type II respiratory failure. Methods: A total of 80 patients with COPD and type Ⅱ respiratory failure were randomly divided into observation group and control group (n=40, control group received symptomatic treatment + aminophylline treatment, observation group received symptomatic treatment + aminophylline + noninvasive positive pressure ventilation treatment, and then differences in blood gas parameters, pulmonary function parameters, hemorheology parameters and inflammatory factor levels were compared between two groups of patients after treatment. Results: Radial artery pH and PO2 values of observation group after treatment were higher than those of control group while PCO2, Cl- and CO2CP values were lower than those of control group; pulmonary function parameters FVC, FEV1, FEF25-75, MMF, PEF and FRC values of observation group after treatment were higher than those of control group; whole blood viscosity (150 s- and 10 s-, plasma viscosity, fibrinogen, erythrocyte aggregation index and erythrocyte rigidity index values in peripheral venous blood of observation group after treatment were lower than those of control group; serum IL-17, IL-33, TREM-1, sICAM-1 and PGE2 levels of observation group after treatment were lower than those of control group. Conclusion: Noninvasive positive pressure ventilation combined with aminophylline can optimize the respiratory function of patients with COPD and type II respiratory failure and improve blood gas parameters and the degree of inflammation.

Lump Kinetic Analysis of Syngas Composition Effect on Fischer-Tropsch Synthesis over Cobalt and Cobalt-Rhenium Alumina Supported Catalyst

Directory of Open Access Journals (Sweden)

Dewi Tristantini

2016-03-01

Received: 10th November 2015; Revised: 10th February 2016; Accepted: 16th February 2016 How to Cite: Tristantini, D., Suwignjo, R.K. (2016. Lump Kinetic Analysis of Syngas Composition Effect on Fischer-Tropsch Synthesis over Cobalt and Cobalt-Rhenium Alumina Supported Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 84-92. (doi:10.9767/bcrec.11.1.424.84-92 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.424.84-92

Experimental validation for combustion analysis of GOTHIC code in 2-dimensional combustion chamber

International Nuclear Information System (INIS)

Lee, J. W.; Yang, S. Y.; Park, K. C.; Jung, S. H.

2002-01-01

In this study, the prediction capability of GOTHIC code for hydrogen combustion phenomena was validated with the results of two-dimensional premixed hydrogen combustion experiment executed by Seoul National University. The experimental chamber has about 24 liter free volume (1x0.024x1 m 3 ) and 2-dimensional rectangular shape. The test were preformed with 10% hydrogen/air gas mixture and conducted with combination of two igniter positions (top center, top corner) and two boundary conditions (bottom full open, bottom right half open). Using the lumped parameter and mechanistic combustion model in GOTHIC code, the SNU experiments were simulated under the same conditions. The GOTHIC code prediction of the hydrogen combustion phenomena did not compare well with the experimental results. In case of lumped parameter simulation, the combustion time was predicted appropriately. But any other local information related combustion phenomena could not be obtained. In case of mechanistic combustion analysis, the physical combustion phenomena of gas mixture were not matched experimental ones. In boundary open cases, the GOTHIC predicted very long combustion time and the flame front propagation could not simulate appropriately. Though GOTHIC showed flame propagation phenomenon in adiabatic calculation, the induction time of combustion was still very long compare with experimental results. Also, it was found that the combustion model of GOTHIC code had some weak points in low concentration of hydrogen combustion simulation

Effects of different SSI parameters on the floor response spectra of a nuclear reactor building

International Nuclear Information System (INIS)

Kabir, A.F.; Bolourchi, S.; Maryak, M.E.

1991-01-01

The effects of several critical soil-structure interaction (SSI) parameters on the floor response spectra (FRS) of a typical nuclear reactor building have been examined. These parameters are computation of soil impedance functions using different approaches, scattering effects (reductions in ground motion due to embedment and rigidity of building foundation) and strain dependency of soil dynamic properties. This paper reports that the significant conclusions of the study, which are applicable to a deeply embedded very rigid nuclear reactor building, are as follows: FRS generated without considering scattering effects are highly conservative; differences between FRS, generated considering strain-dependency of soil dynamic properties, and those generated suing low-strain values, are not significant; and the lumped-parameter approach of SSI calculations, which only uses a single value of soil shear modulus in impedance calculations, may not be able to properly compute the soil impedances for a soil deposit with irregularly varying properties with depth

Removal in a lump of JRR-3 nuclear reactor

International Nuclear Information System (INIS)

Ohnishi, Nobuaki; Suzuki, Masanori; Nagase, Tetsuo; Watanabe, Morinari.

1989-01-01

The research reactor JRR-3 in Japan Atomic Energy Research Institute is called 'Home made No.1 reactor' as all except fuel and heavy water as the moderator and coolant were manufactured in Japan. The JRR-3 attained the criticality in 1962, and the cumulative time of operation reached 47135.5 hours, and the cumulative power output reached 419073.5 MWh. It was stopped in 1983. During the period, it was utilized for beam experiment, irradiation of fuel and materials, RI production and others. In order to cope with the expansion of utilization and the advance of utilizing technology of the research reactor, the reconstruction works are in progress, and the criticality of the reconstructed reactor is expected in 1990. On the site where the old reactor is removed, the reactor of different type is installed, and the first large cold neutron source is equipped. In this report, as to the removal of the old reactor proper, the method of working and the results are described. Considering the period of working, the cost and the management of the removed reactor, in the case of the JRR-3, the method of carrying it out in a lump was adopted as the optimum removal method. The plan, procedure and results of the removal working are reported. (K.I.)

Simplified distributed parameters BWR dynamic model for transient and stability analysis

International Nuclear Information System (INIS)

Espinosa-Paredes, Gilberto; Nunez-Carrera, Alejandro; Vazquez-Rodriguez, Alejandro

2006-01-01

This paper describes a simplified model to perform transient and linear stability analysis for a typical boiling water reactor (BWR). The simplified transient model was based in lumped and distributed parameters approximations, which includes vessel dome and the downcomer, recirculation loops, neutron process, fuel pin temperature distribution, lower and upper plenums reactor core and pressure and level controls. The stability was determined by studying the linearized versions of the equations representing the BWR system in the frequency domain. Numerical examples are used to illustrate the wide application of the simplified BWR model. We concluded that this simplified model describes properly the dynamic of a BWR and can be used for safety analysis or as a first approach in the design of an advanced BWR

Life-cycle analysis of shale gas and natural gas.

Energy Technology Data Exchange (ETDEWEB)

Clark, C.E.; Han, J.; Burnham, A.; Dunn, J.B.; Wang, M. (Energy Systems); ( EVS)

2012-01-27

The technologies and practices that have enabled the recent boom in shale gas production have also brought attention to the environmental impacts of its use. Using the current state of knowledge of the recovery, processing, and distribution of shale gas and conventional natural gas, we have estimated up-to-date, life-cycle greenhouse gas emissions. In addition, we have developed distribution functions for key parameters in each pathway to examine uncertainty and identify data gaps - such as methane emissions from shale gas well completions and conventional natural gas liquid unloadings - that need to be addressed further. Our base case results show that shale gas life-cycle emissions are 6% lower than those of conventional natural gas. However, the range in values for shale and conventional gas overlap, so there is a statistical uncertainty regarding whether shale gas emissions are indeed lower than conventional gas emissions. This life-cycle analysis provides insight into the critical stages in the natural gas industry where emissions occur and where opportunities exist to reduce the greenhouse gas footprint of natural gas.

Gas Permeation Characteristics across Nano-Porous Inorganic Membranes

Directory of Open Access Journals (Sweden)

M.R Othman, H. Mukhtar

2012-10-01

Full Text Available An overview of parameters affecting gas permeation in inorganic membranes is presented. These factors include membrane physical characteristics, operational parameters and gas molecular characteristics. The membrane physical characteristics include membrane materials and surface area, porosity, pore size and pore size distribution and membrane morphology. The operational parameters include feed flow rate and concentration, stage cut, temperature and pressure. The gas molecular characteristics include gas molecular weight, diameter, critical temperature, critical pressure, Lennard-Jones parameters and diffusion volumes. The current techniques of material characterization may require complementary method in describing microscopic heterogeneity of the porous ceramic media. The method to be incorporated in the future will be to apply a stochastic model and/or fractal dimension. Keywords: Inorganic membrane, surface adsorption, Knudsen diffusion, Micro-porous membrane, permeation, gas separation.

Impact of model structure on flow simulation and hydrological realism: from a lumped to a semi-distributed approach

Science.gov (United States)

Garavaglia, Federico; Le Lay, Matthieu; Gottardi, Fréderic; Garçon, Rémy; Gailhard, Joël; Paquet, Emmanuel; Mathevet, Thibault

2017-08-01

Model intercomparison experiments are widely used to investigate and improve hydrological model performance. However, a study based only on runoff simulation is not sufficient to discriminate between different model structures. Hence, there is a need to improve hydrological models for specific streamflow signatures (e.g., low and high flow) and multi-variable predictions (e.g., soil moisture, snow and groundwater). This study assesses the impact of model structure on flow simulation and hydrological realism using three versions of a hydrological model called MORDOR: the historical lumped structure and a revisited formulation available in both lumped and semi-distributed structures. In particular, the main goal of this paper is to investigate the relative impact of model equations and spatial discretization on flow simulation, snowpack representation and evapotranspiration estimation. Comparison of the models is based on an extensive dataset composed of 50 catchments located in French mountainous regions. The evaluation framework is founded on a multi-criterion split-sample strategy. All models were calibrated using an automatic optimization method based on an efficient genetic algorithm. The evaluation framework is enriched by the assessment of snow and evapotranspiration modeling against in situ and satellite data. The results showed that the new model formulations perform significantly better than the initial one in terms of the various streamflow signatures, snow and evapotranspiration predictions. The semi-distributed approach provides better calibration-validation performance for the snow cover area, snow water equivalent and runoff simulation, especially for nival catchments.

Effect of piping systems on surge in centrifugal compressors

International Nuclear Information System (INIS)

Tamaki, Hideaki

2008-01-01

There is a possibility that the exchange of the piping system may change the surge characteristic of a compressor. The piping system of a plant is not always the same as that of a test site. Then it is important to evaluate the effect of piping systems on surge characteristics in centrifugal compressors. Several turbochargers combined with different piping systems were tested. The lumped parameter model which was simplified to be solved easily was applied for the prediction of surge point. Surge lines were calculated with the linearlized lumped parameter model. The difference between the test and calculated results was within 10 %. Trajectory of surge cycle was also examined by solving the lumped parameter model. Mild surge and deep surge were successfully predicted. This study confirmed that the lumped parameter model was a very useful tool to predict the effect of piping systems on surge characteristics in centrifugal compressors, even though that was a simple model

Isolated tear of the tendon to the medial head of gastrocnemius presenting as a painless lump in the calf

OpenAIRE

Watura, Christopher; Harries, William

2009-01-01

We report on a case of isolated tear of the medial head of gastrocnemius tendon. The patient presented with a painless lump in the right calf and denied any prior history of trauma or strain to the leg. A longitudinal split of the tendon was demonstrated at ultrasound and magnetic resonance imaging (MRI). There were no other abnormalities and the gastrocnemius muscle was normal. There are no reports in the literature of isolated gastrocnemius tendon tear. To date the calf muscle complex injur...

Gas component parameters in the nucleus of galaxy NGC5879

International Nuclear Information System (INIS)

Petrov, G.T.; Mineva, V.A.; Kyazumov, G.A.

1984-01-01

Relative intensities of the emission lines from the nucleus of galaxy NGC 5879 are determined, using spectra obtained by the 125-cm ZTE telescope at the Crimea Station of State Astronomical Institute Shane. On the basis of these data, the luminosity in the line HSUB(α) is determined: LSUB(Hα)= 3.43.10 38 erg/sec; also the mass of gas: MSUB(gas)= 1.10 36 g, and other quantities, for H=75 km/s Mpc. The electron density of the gas, nSUB(e), is estimated to be 1550 cm -3 . Nitrogen and sulphur ion contents are correspondingly lgN + =7.09 and lgS + =6.53, assuming lgH=12.00. The NGC 5879 galaxy exibits a weak activity, expressed in relatively strong emission lines, and can be referred to galaxies of the M51 or M81 type, studied in detail by Peimbert

Risk Analysis using Corrosion Rate Parameter on Gas Transmission Pipeline

Science.gov (United States)

Sasikirono, B.; Kim, S. J.; Haryadi, G. D.; Huda, A.

2017-05-01

In the oil and gas industry, the pipeline is a major component in the transmission and distribution process of oil and gas. Oil and gas distribution process sometimes performed past the pipeline across the various types of environmental conditions. Therefore, in the transmission and distribution process of oil and gas, a pipeline should operate safely so that it does not harm the surrounding environment. Corrosion is still a major cause of failure in some components of the equipment in a production facility. In pipeline systems, corrosion can cause failures in the wall and damage to the pipeline. Therefore it takes care and periodic inspections or checks on the pipeline system. Every production facility in an industry has a level of risk for damage which is a result of the opportunities and consequences of damage caused. The purpose of this research is to analyze the level of risk of 20-inch Natural Gas Transmission Pipeline using Risk-based inspection semi-quantitative based on API 581 associated with the likelihood of failure and the consequences of the failure of a component of the equipment. Then the result is used to determine the next inspection plans. Nine pipeline components were observed, such as a straight pipes inlet, connection tee, and straight pipes outlet. The risk assessment level of the nine pipeline’s components is presented in a risk matrix. The risk level of components is examined at medium risk levels. The failure mechanism that is used in this research is the mechanism of thinning. Based on the results of corrosion rate calculation, remaining pipeline components age can be obtained, so the remaining lifetime of pipeline components are known. The calculation of remaining lifetime obtained and the results vary for each component. Next step is planning the inspection of pipeline components by NDT external methods.

Maternal Body Mass Index Does Not Affect Neonatal Umbilical Artery Blood Gas Parameters

Directory of Open Access Journals (Sweden)

Salam E. Chalouhi

2013-01-01

Full Text Available This study was undertaken to assess the impact of obesity on fetal well-being in glucose-tolerant and nonhypertensive women. Medical charts of all patients admitted to the labor and delivery department at our institution between January, 2011 and July, 2011 were retrospectively reviewed. Patients with diabetes/impaired glucose tolerance or hypertension were excluded. A total of 100 women, 50 lean and 50 obese, were included. Umbilical artery blood gas parameters (BGPs were compared in lean (<25 kg/m2 and obese (≥30 kg/m2 women. Obese and lean women were comparable with respect to all baseline characteristics. There was no difference in any of the BGP or Apgar scores between obese and lean patients. Pearson’s correlation coefficient found no significant correlation between BMI and BGP/Apgar scores. Maternal obesity does not seem to affect BGP and fetal well-being in glucose-tolerant and nonhypertensive women.

General 3D Lumped Thermal Model with Various Boundary Conditions for High Power IGBT Modules

DEFF Research Database (Denmark)

Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede

2016-01-01

Accurate thermal dynamics modeling of high power Insulated Gate Bipolar Transistor (IGBT) modules is important information for the reliability analysis and thermal design of power electronic systems. However, the existing thermal models have their limits to correctly predict these complicated...... thermal behaviors in the IGBTs. In this paper, a new three-dimensional (3D) lumped thermal model is proposed, which can easily be characterized from Finite Element Methods (FEM) based simulation and acquire the thermal distribution in critical points. Meanwhile the boundary conditions including...... the cooling system and power losses are modeled in the 3D thermal model, which can be adapted to different real field applications of power electronic converters. The accuracy of the proposed thermal model is verified by experimental results....

Computational Fluid Dynamics-Population Balance Model Simulation of Effects of Cell Design and Operating Parameters on Gas-Liquid Two-Phase Flows and Bubble Distribution Characteristics in Aluminum Electrolysis Cells

Science.gov (United States)

Zhan, Shuiqing; Wang, Junfeng; Wang, Zhentao; Yang, Jianhong

2018-02-01

The effects of different cell design and operating parameters on the gas-liquid two-phase flows and bubble distribution characteristics under the anode bottom regions in aluminum electrolysis cells were analyzed using a three-dimensional computational fluid dynamics-population balance model. These parameters include inter-anode channel width, anode-cathode distance (ACD), anode width and length, current density, and electrolyte depth. The simulations results show that the inter-anode channel width has no significant effect on the gas volume fraction, electrolyte velocity, and bubble size. With increasing ACD, the above values decrease and more uniform bubbles can be obtained. Different effects of the anode width and length can be concluded in different cell regions. With increasing current density, the gas volume fraction and electrolyte velocity increase, but the bubble size keeps nearly the same. Increasing electrolyte depth decreased the gas volume fraction and bubble size in particular areas and the electrolyte velocity increased.

A study of the consistent and the lumped source approximations in finite element neutron diffusion calculations

International Nuclear Information System (INIS)

Ozgener, B.; Azgener, H.A.

1991-01-01

In finite element formulations for the solution of the within-group neutron diffusion equation, two different treatments are possible for the group source term: the consistent source approximation (CSA) and the lumped source approximation (LSA). CSA results in intra-group scattering and fission matrices which have the same nondiagonal structure as the global coefficient matrix. This situation might be regarded as a disadvantage, compared to the conventional (i.e. finite difference) methods where the intra-group scattering and fission matrices are diagonal. To overcome this disadvantage, LSA could be used to diagonalize these matrices. LSA is akin to the lumped mass approximation of continuum mechanics. We concentrate on two different aspects of the source approximations. Although it has been reported that LSA does not modify the asymptotic h 2 convergence behaviour for linear elements, the effect of LSA on convergence of higher degree elements has not been investigated. Thus, we would be interested in determining, p, the asymptotic order of convergence, in: Δk |k eff (analytical) -k eff (finite element)| = Ch p (1) for finite element approximations of varying degree (N) with both of the source approximations. Since (1) is valid in the asymptotic limit, we must use ultra-fine meshes and quadruple precision arithmetic. For our order of convergence study, we used infinite cylindrical geometry with azimuthal symmetry. Hence, the effects of singularities remain uninvestigated. The second aspect we dwell on is the performance of LSA in bilinear 3-D finite element calculations, compared to CSA. LSA has been used quite extensively in 1- and 2-D even-parity transport and diffusion calculations. In this work, we will try to assess the relative merits of LSA and CSA in 3-D problems. (author)

Genetic algorithm based optimization of the process parameters for gas metal arc welding of AISI 904 L stainless steel

International Nuclear Information System (INIS)

Sathiya, P.; Ajith, P. M.; Soundararajan, R.

2013-01-01

The present study is focused on welding of super austenitic stainless steel sheet using gas metal arc welding process with AISI 904 L super austenitic stainless steel with solid wire of 1.2 mm diameter. Based on the Box - Behnken design technique, the experiments are carried out. The input parameters (gas flow rate, voltage, travel speed and wire feed rate) ranges are selected based on the filler wire thickness and base material thickness and the corresponding output variables such as bead width (BW), bead height (BH) and depth of penetration (DP) are measured using optical microscopy. Based on the experimental data, the mathematical models are developed as per regression analysis using Design Expert 7.1 software. An attempt is made to minimize the bead width and bead height and maximize the depth of penetration using genetic algorithm.

Genetic algorithm based optimization of the process parameters for gas metal arc welding of AISI 904 L stainless steel

Energy Technology Data Exchange (ETDEWEB)

Sathiya, P. [National Institute of Technology Tiruchirappalli (India); Ajith, P. M. [Department of Mechanical Engineering Rajiv Gandhi Institute of Technology, Kottayam (India); Soundararajan, R. [Sri Krishna College of Engineering and Technology, Coimbatore (India)

2013-08-15

The present study is focused on welding of super austenitic stainless steel sheet using gas metal arc welding process with AISI 904 L super austenitic stainless steel with solid wire of 1.2 mm diameter. Based on the Box - Behnken design technique, the experiments are carried out. The input parameters (gas flow rate, voltage, travel speed and wire feed rate) ranges are selected based on the filler wire thickness and base material thickness and the corresponding output variables such as bead width (BW), bead height (BH) and depth of penetration (DP) are measured using optical microscopy. Based on the experimental data, the mathematical models are developed as per regression analysis using Design Expert 7.1 software. An attempt is made to minimize the bead width and bead height and maximize the depth of penetration using genetic algorithm.

Development of CAP code for nuclear power plant containment: Lumped model

Energy Technology Data Exchange (ETDEWEB)

Hong, Soon Joon, E-mail: sjhong90@fnctech.com [FNC Tech. Co. Ltd., Heungdeok 1 ro 13, Giheung-gu, Yongin-si, Gyeonggi-do 446-908 (Korea, Republic of); Choo, Yeon Joon; Hwang, Su Hyun; Lee, Byung Chul [FNC Tech. Co. Ltd., Heungdeok 1 ro 13, Giheung-gu, Yongin-si, Gyeonggi-do 446-908 (Korea, Republic of); Ha, Sang Jun [Central Research Institute, Korea Hydro & Nuclear Power Company, Ltd., 70, 1312-gil, Yuseong-daero, Yuseong-gu, Daejeon 305-343 (Korea, Republic of)

2015-09-15

Highlights: • State-of-art containment analysis code, CAP, has been developed. • CAP uses 3-field equations, water level oriented upwind scheme, local head model. • CAP has a function of linked calculation with reactor coolant system code. • CAP code assessments showed appropriate prediction capabilities. - Abstract: CAP (nuclear Containment Analysis Package) code has been developed in Korean nuclear society for the analysis of nuclear containment thermal hydraulic behaviors including pressure and temperature trends and hydrogen concentration. Lumped model of CAP code uses 2-phase, 3-field equations for fluid behaviors, and has appropriate constitutive equations, 1-dimensional heat conductor model, component models, trip and control models, and special process models. CAP can run in a standalone mode or a linked mode with a reactor coolant system analysis code. The linked mode enables the more realistic calculation of a containment response and is expected to be applicable to a more complicated advanced plant design calculation. CAP code assessments were carried out by gradual approaches: conceptual problems, fundamental phenomena, component and principal phenomena, experimental validation, and finally comparison with other code calculations on the base of important phenomena identifications. The assessments showed appropriate prediction capabilities of CAP.

Development of CAP code for nuclear power plant containment: Lumped model

International Nuclear Information System (INIS)

Hong, Soon Joon; Choo, Yeon Joon; Hwang, Su Hyun; Lee, Byung Chul; Ha, Sang Jun

2015-01-01

Highlights: • State-of-art containment analysis code, CAP, has been developed. • CAP uses 3-field equations, water level oriented upwind scheme, local head model. • CAP has a function of linked calculation with reactor coolant system code. • CAP code assessments showed appropriate prediction capabilities. - Abstract: CAP (nuclear Containment Analysis Package) code has been developed in Korean nuclear society for the analysis of nuclear containment thermal hydraulic behaviors including pressure and temperature trends and hydrogen concentration. Lumped model of CAP code uses 2-phase, 3-field equations for fluid behaviors, and has appropriate constitutive equations, 1-dimensional heat conductor model, component models, trip and control models, and special process models. CAP can run in a standalone mode or a linked mode with a reactor coolant system analysis code. The linked mode enables the more realistic calculation of a containment response and is expected to be applicable to a more complicated advanced plant design calculation. CAP code assessments were carried out by gradual approaches: conceptual problems, fundamental phenomena, component and principal phenomena, experimental validation, and finally comparison with other code calculations on the base of important phenomena identifications. The assessments showed appropriate prediction capabilities of CAP

SALT [System Analysis Language Translater]: A steady state and dynamic systems code

International Nuclear Information System (INIS)

Berry, G.; Geyer, H.

1983-01-01

SALT (System Analysis Language Translater) is a lumped parameter approach to system analysis which is totally modular. The modules are all precompiled and only the main program, which is generated by SALT, needs to be compiled for each unique system configuration. This is a departure from other lumped parameter codes where all models are written by MACROS and then compiled for each unique configuration, usually after all of the models are lumped together and sorted to eliminate undetermined variables. The SALT code contains a robust and sophisticated steady-sate finder (non-linear equation solver), optimization capability and enhanced GEAR integration scheme which makes use of sparsity and algebraic constraints. The SALT systems code has been used for various technologies. The code was originally developed for open-cycle magnetohydrodynamic (MHD) systems. It was easily extended to liquid metal MHD systems by simply adding the appropriate models and property libraries. Similarly, the model and property libraries were expanded to handle fuel cell systems, flue gas desulfurization systems, combined cycle gasification systems, fluidized bed combustion systems, ocean thermal energy conversion systems, geothermal systems, nuclear systems, and conventional coal-fired power plants. Obviously, the SALT systems code is extremely flexible to be able to handle all of these diverse systems. At present, the dynamic option has only been used for LMFBR nuclear power plants and geothermal power plants. However, it can easily be extended to other systems and can be used for analyzing control problems. 12 refs

Parameter identification and model validation for the piezoelectric actuator in an inertia motor

International Nuclear Information System (INIS)

Hunstig, Matthias; Hemsel, Tobias

2010-01-01

Piezoelectric inertia motors make use of the inertia of a slider to drive the slider by friction contact in a series of small steps which are generally composed of a stick phase and a slip phase. If the best electrical drive signal for the piezoelectric actuator in an inertia motor is to be determined, its dynamical behaviour must be known. A classic dynamic lumped parameter model for piezoelectric actuators is valid only in resonance and, therefore, is not suitable for modelling the actuator in an inertia motor. A reduced dynamic model is used instead. Its parameters are identified using a step response measurement. This model is used to predict the movement of the actuator in response to a velocity-optimized signal introduced in a separate contribution. Results show that the model cannot represent the dynamical characteristics of the actuator completely. For determining voltage signals that let piezoelectric actuators follow a calculated movement pattern exactly, the model can, therefore, only be used with limitations.

EXPERIMENTAL INVESTIGATION OF EMISSION AND PERFORMANCE PARAMETERS OF PONGAMIA BIODIESEL AND HHO GAS ADDITION IN A COMPRESSION IGNITION ENGINE

OpenAIRE

Allen Jeffrey.J1, Divya Meena.S2, Balaji.P3, Bharathi.K4, Arvind Raj.R5

2018-01-01

Nowadays the environmental pollution has been increased incredibly by using conventional fuels. To control this increase in pollution alternate fuels has to be used as supplement for conventional fuels. While using conventional fuels such as petrol and diesel in IC engine there is a chance of increase in emissions. Alternate fuels can control emissions. This work is based on the investigation of emission parameters of pongamia biodiesel and HHO gas addition in a CI engine. Pongamia biodiesel ...

Vacuum system for the Argonne 6 GeV synchrotron light source

International Nuclear Information System (INIS)

Wehrle, R.; Moenich, J.

1985-01-01

The ANL vacuum system for the 6 GeV light source storage ring features non-evaporable strip getter pumps for uniform pumping around the ring within a gas desorption antechamber, and it also features lumped getter pumping directly under and above crotch radiation absorbers that are positioned after each bending magnet. Based on experiments at ANL in 1980 and by others, the technical and economical advantages have been established for the use of the distributed NeG pumps of non-magnetic strips coated with a non-evaporable Zr Al getter matrix. The NeG strip pump lifetime approaches ten years. The antechamber improves the isolation of the gas desorption process from the main beam chamber and beam. The combination of these vacuum techniques; the NeG strip getter pumps, the gas desorption antechambers, and the lumped ion and lumped getter pumping provide a unique and reliable system for maintaining long beam lifetime

Mass Spectrometry Parameters Optimization for the 46 Multiclass Pesticides Determination in Strawberries with Gas Chromatography Ion-Trap Tandem Mass Spectrometry

Science.gov (United States)

Fernandes, Virgínia C.; Vera, Jose L.; Domingues, Valentina F.; Silva, Luís M. S.; Mateus, Nuno; Delerue-Matos, Cristina

2012-12-01

Multiclass analysis method was optimized in order to analyze pesticides traces by gas chromatography with ion-trap and tandem mass spectrometry (GC-MS/MS). The influence of some analytical parameters on pesticide signal response was explored. Five ion trap mass spectrometry (IT-MS) operating parameters, including isolation time (IT), excitation voltage (EV), excitation time (ET), maximum excitation energy or " q" value (q), and isolation mass window (IMW) were numerically tested in order to maximize the instrument analytical signal response. For this, multiple linear regression was used in data analysis to evaluate the influence of the five parameters on the analytical response in the ion trap mass spectrometer and to predict its response. The assessment of the five parameters based on the regression equations substantially increased the sensitivity of IT-MS/MS in the MS/MS mode. The results obtained show that for most of the pesticides, these parameters have a strong influence on both signal response and detection limit. Using the optimized method, a multiclass pesticide analysis was performed for 46 pesticides in a strawberry matrix. Levels higher than the limit established for strawberries by the European Union were found in some samples.

A method to measure the thermal-physical parameter of gas hydrate in porous media

Energy Technology Data Exchange (ETDEWEB)

Diao, S.B.; Ye, Y.G.; Yue, Y.J.; Zhang, J.; Chen, Q.; Hu, G.W. [Qingdao Inst. of Marine Geology, Qingdao (China)

2008-07-01

It is important to explore and make good use of gas hydrates through the examination of the thermal-physical parameters of sediment. This paper presented a new type of simulation experiment using a device that was designed based on the theories of time domain reflection and transient hot wire method. A series of investigations were performed using this new device. The paper described the experiment, with reference to the experiment device and materials and method. It also presented the results of thermal physical properties; result of the thermal conductivity of water, dry sand and wet sand; and results of wet sand under various pressures. The time domain reflection (TDR) method was utilized to monitor the saturation of the hydrates. Both parallel hot-wire method and cross hot-wire method were utilized to measure the thermal conductivity of the gas hydrate in porous media. A TDR sensor which was equipped with both cross hot-wire probe and parallel hot-wire probe was developed in order to measure the cell temperature with these two methods at one time. It was concluded that the TDR probe could be taken as an online measurement skill in investigating the hydrate thermal physical property in porous media. The TDR sensor could monitor the hydrate formation process and the parallel hot-wire method and cross hot-wire method could effectively measure the thermal physical properties of the hydrates in porous media. 10 refs., 7 figs.

Health monitoring system for transmission shafts based on adaptive parameter identification

Science.gov (United States)

Souflas, I.; Pezouvanis, A.; Ebrahimi, K. M.

2018-05-01

A health monitoring system for a transmission shaft is proposed. The solution is based on the real-time identification of the physical characteristics of the transmission shaft i.e. stiffness and damping coefficients, by using a physical oriented model and linear recursive identification. The efficacy of the suggested condition monitoring system is demonstrated on a prototype transient engine testing facility equipped with a transmission shaft capable of varying its physical properties. Simulation studies reveal that coupling shaft faults can be detected and isolated using the proposed condition monitoring system. Besides, the performance of various recursive identification algorithms is addressed. The results of this work recommend that the health status of engine dynamometer shafts can be monitored using a simple lumped-parameter shaft model and a linear recursive identification algorithm which makes the concept practically viable.

Methods for calculation of engineering parameters for gas separation. [vapor pressure and solubility of gases in organic liquids

Science.gov (United States)

Lawson, D. D.

1979-01-01

A group additivity method is generated which allows estimation, from the structural formulas alone, of the energy of vaporization and the molar volume at 25 C of many nonpolar organic liquids. Using these two parameters and appropriate thermodynamic relations, the vapor pressure of the liquid phase and the solubility of various gases in nonpolar organic liquids are predicted. It is also possible to use the data to evaluate organic and some inorganic liquids for use in gas separation stages or liquids as heat exchange fluids in prospective thermochemical cycles for hydrogen production.

Development of a new simulation code for evaluation of criticality transients involving fissile solution boiling

International Nuclear Information System (INIS)

Basoglu, Benan; Yamamoto, Toshihiro; Okuno, Hiroshi; Nomura, Yasushi

1998-03-01

In this work, we report on the development of a new computer code named TRACE for predicting the excursion characteristics of criticality excursions involving fissile solutions. TRACE employs point neutronics coupled with simple thermal-hydraulics. The temperature, the radiolytic gas effects, and the boiling phenomena are estimated using the transient heat conduction equation, a lumped-parameter energy model, and a simple boiling model, respectively. To evaluate the model, we compared our results with the results of CRAC experiments. The agreement in these comparisons is quite satisfactory. (author)

INCIDENCE OF BENIGN BREAST LUMP ABOVE 40 YRS. OF AGE IN FEMALE ATTENDING MGMGH, TIRUCHIRAPPALLI

Directory of Open Access Journals (Sweden)

Ayyaswamy Thulasi

2016-10-01

Full Text Available BACKGROUND AND OBJECTIVES The breast is the essential symbol of womanhood to society and to the woman herself. Subjected every month to the onslaught of ovarian, adrenal, pituitary and thyroid hormones in tandem with the uterus, the very histological architecture of the breast changes sequentially. With the recent importance given to early diagnosis of cancer of the breast and its early detection by both the patient and her physician, more benign conditions are likely to be detected than earlier. The objective of our review is to find out the incidence of benign breast lump above 40 years of age in females attending our hospital. METHODS AND MATERIALS 130 patients presenting to the outpatient department of KAPV Medical College with breast lump were included in this comprehensive study. A detailed history regarding the duration and nature of the complaints, family history pertaining to breast or ovarian cancers, risk factors such as oral contraceptive use, parity, lactation, etc. was elicited. A thorough clinical examination was performed. RESULTS Of 24 cases of fibroadenoma, all were operated upon by excision. Of 38 patients with fibroadenosis, 30 patients managed conservatively and surgery for 8 patients where the diagnosis was doubtful. Abscesses were incised and drained under antibiotic cover for 3 patients. 8 cases of breast cyst were managed by aspiration. TB mastitis was confirmed by excisional biopsy and followed up by antituberculous therapy with regular follow up after 6 months. Healed lesions were found to be associated with improved general condition of the patients. Lipoma and sebaceous cyst were managed by excision biopsy. CONCLUSION Benign breast diseases were found to be common in woman above 40 years old in contrast to normal teaching, which says they are common in younger age groups. Fibroadenosis was the commonest benign disease closely followed by fibroadenoma. Fibroadenosis was mostly managed conservatively. Excision biopsy

Gas flow parameter determination by molecular beam method

International Nuclear Information System (INIS)

Zarvin, A.E.; Sharafutdinov, R.G.

1977-01-01

This paper describes a molecular-beam system intended for studying nonequilibrium processes in supersonic rarefied gas flows. The system represented is a small molecular beam source placed inside the low intensity wind tunnel of the Institute of Thermophysics, Siberian Branch of the USSR Academy of Sciences. The time-of-flight method is used for measuring molecular velocity distribution functions on molecular beam axis. (Auth.)

Effect of Gamma Irradiation and Chemical Process on Gas Production Parameters of some Agricultural By-products in in vitro

Directory of Open Access Journals (Sweden)

S. Sobhanirad

2013-03-01

Full Text Available The aim of this study was investigating the effect of gamma irradiation and NaOH treatment of some agricultural by products (tomato pulp, orange pulp, pistachio hull and wheat straw on fermentation parameters and gas production test. Treatments of gamma irradiation (50, 100 and 200 kGy and %5 NaOH was done on each source of by products. The results showed that gamma irradiation at the dose of 200 kGy numerically and %5 NaOH increased (P

Tables of nuclear level density parameters

International Nuclear Information System (INIS)

Chatterjee, A.; Ghosh, S.K.; Majumdar, H.

1976-03-01

The Renormalized Gas Model (RGM) has been used to calculate single particle level density parameters for more than 2000 nucleides over the range 9<=Z<=126 (15<=A<=338). Three separate tables present the elements on or near the valley of beta stability, neutron-rich fission fragment nucleides, and transitional nuclei, actinides and light-mass super heavy elements. Each table identifies the nucleus in terms of Z and N and presents the RGM deformation energy of binding, the total RGM structural energy correction over the free gas Fermi surface, and the level density parameter

Intelligent gas-mixture flow sensor

NARCIS (Netherlands)

Lammerink, Theodorus S.J.; Dijkstra, Fred; Houkes, Z.; van Kuijk, J.C.C.; van Kuijk, Joost

A simple way to realize a gas-mixture flow sensor is presented. The sensor is capable of measuring two parameters from a gas flow. Both the flow rate and the helium content of a helium-nitrogen gas mixture are measured. The sensor exploits two measurement principles in combination with (local)

Dross formation during laser cutting process

Energy Technology Data Exchange (ETDEWEB)

Yilbas, B S; Aleem, B J Abdul [Mechanical Engineering Department, King Fahd University of Petoleum and Minerals, Dhahran 32161 (Saudi Arabia)

2006-04-07

Melt formation during laser cutting of metallic substrates is considered and the melt thickness is formulated using a lump parameter analysis. The droplet diameter is also predicted and compared with the experimental results. A CO{sub 2} laser with variable pulse frequency is used in the experiment. Oxygen, as assisting gas, impinging coaxially with the laser beam, is used at different pressures. SEM and XRD are carried out to obtain micrographs and oxide compounds formed in the dross. It is found that the liquid layer thickness increases with increasing laser output power and reduces with increasing assisting gas velocity. The droplet formed is spherical and the droplet size predicted agrees well with the experimental results.

Raising lump coke formation capacity of semicoking briquets in the Deuben briquetting plant

Energy Technology Data Exchange (ETDEWEB)

Naundorf, W.; Trommer, D.; Schroeder, H.-W.; Dressler, H.

1988-01-01

Describes brown coal briquetting and coking experiments aimed at producing high quality lumpy coke suitable for heating, metallurgy and other industrial processes. The Deuben coking and gas plant produces low temperature carbonization briquets from coal with 13.2% ash content, 54.8% volatiles, 13.5% semicoking tar with the effect that coke produced from these briquets disintegrates completely into fines (0/15 mm grain size). The study centered on effects of briquetting and coking parameters including coal grain size, coal moisture, briquetting pressure, coking temperature, heating rate and application of sulfite liquor as binder. Graphs of briquetting and coking results are provided. The Deuben coal was shown to be suitable for producing lumpy coke (11.5 to over 20 MPa compression strength) from coal under the optimum briquetting parameters of 0/1 mm grain size, 11% coal moisture, briquetting temperature of 70 to 80 C and briquetting pressure over 120 MPa. Use of a binder was found to be advantageous but not necessary. The produced coke showed favorable combustion properties. 6 refs.

Effects of Geometry Design Parameters on the Static Strength and Dynamics for Spiral Bevel Gear

Directory of Open Access Journals (Sweden)

Zhiheng Feng

2017-01-01

Full Text Available Considering the geometry design parameters, a quasi-static mesh model of spiral bevel gears was established and the mesh characteristics were computed. Considering the time-varying effects of mesh points, mesh force, line-of-action vector, mesh stiffness, transmission error, friction force direction, and friction coefficient, a nonlinear lumped parameter dynamic model was developed for the spiral bevel gear pair. Based on the mesh model and the nonlinear dynamic model, the effects of main geometry parameters on the contact and bending strength were analyzed. Also, the effects on the dynamic mesh force and dynamic transmission error were investigated. Results show that higher value for the pressure angle, root fillet radius, and the ratio of tooth thickness tend to improve the contact and bending strength and to reduce the risk of tooth fracture. Improved gears have a better vibration performance in the targeted frequency range. Finally, bench tests for both types of spiral bevel gears were performed. Results show that the main failure mode is the tooth fracture and the life was increased a lot for the spiral bevel gears with improved geometry parameters compared to the original design.

Maximization of Egyptian Gas Oil Production Through the Optimal Use of the Operating Parameters

International Nuclear Information System (INIS)

Marawan, H.

2004-01-01

Gas oil is the major fossil fuel consumed around the world. Global gas oil consumption is rising at a steadily fast pace because of its higher combustion efficiency (versus gasoline). The annual increase rate of gas oil consumption in Egypt is 7 % whereas, the world increase rates range from 1.5 % to 2 % . The main sources for producing gas oil in Egypt refiners is the direct production from the atmospheric distillation process units or it may be produced as a side product from vacuum distillation units . Gas oil is produced through hydrocracking process of vacuum distillation side streams and heavy cocked gas oil. Gas oil production yield can be increased through the existing operation process units. Modifications of the current atmospheric and vacuum tower operations will increase gas oil yield rates to 20 % more than the existing production rates. The modification of the operating conditions and adoption of the optimum catalyst of the existing hydrocracking and mild hydro cracking process units improve gas oil production yield. Operating delayed cocker at high temperatures, low pressure and low cycle ratio also support achieving the maximization of gas oil yield

The challenge of multi-parameter hydrochemical, gas-physical, and isotopic analyses of in-situ clay pore water and samples from in-situ clay experiments

International Nuclear Information System (INIS)

Eichinger, L.; Lorenz, G.D.; Eichinger, F.; Wechner, S.; Voropaev, A.

2012-01-01

Document available in extended abstract form only. Within the research framework of natural clay rocks used as barriers for radioactive waste confinement comprehensive analyses are mandatory to determine the chemical and isotopic composition of natural pore water and therein dissolved gases as well as samples from distinct in-situ and lab experiments. Based on the natural conditions pore waters from low permeable argillaceous rocks can be sampled only in small amounts over long time periods. Often those samples are primarily influenced by processes of the exploration and exploitation such as the contamination by drilling fluid and disinfection fluid or cement-water interactions. Sophisticated equipment for circulation experiments allows the sampling of gas and water in the original state in steel and peek cells. The challenge though is to optimise the lab equipment and measurement techniques in a way that the physical-chemical conditions of the water can be analysed in the original state. The development of special micro measuring cells enables the analyses of physical parameters like redox potential under very slow through-flow conditions. Additional analyses can follow subsequently without wasting any drop of the precious pore water. The gas composition is measured in equilibrated gas phases above water phases after emptying a defined volume by inert gas or through manual pressure. The analytical challenge is to obtain an extensive set of parameters which is considered representative for the in-situ conditions using only a few millilitres of water. The parameter analysis includes the determination of the composition of the water, the isotopic compositions of the water and the dissolved constituents as well as their gas concentrations and isotopic signatures. So far the smallest sample volume needed for an analysis of a full set of parameters including the gas composition was 9 ml of water. Obviously, the analysis requires a highly sophisticated infrastructure and

Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

Science.gov (United States)

Shams, Bilal; Yao, Jun; Zhang, Kai; Zhang, Lei

2017-08-01

Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large amount of condensate in reservoir pores. Trapped condensate often is lost due to condensate accumulation-condensate blockage courtesy of high molecular weight, heavy condensate residue. Recovering lost condensate most economically and optimally has always been a challenging goal. Thus, gas cycling is applied to alleviate such a drastic loss in resources. In gas injection, the flooding pattern, injection timing and injection duration are key parameters to study an efficient EOR scenario in order to recover lost condensate. This work contains sensitivity analysis on different parameters to generate an accurate investigation about the effects on performance of different injection scenarios in homogeneous gas condensate system. In this paper, starting time of gas cycling and injection period are the parameters used to influence condensate recovery of a five-spot well pattern which has an injection pressure constraint of 3000 psi and production wells are constraint at 500 psi min. BHP. Starting injection times of 1 month, 4 months and 9 months after natural depletion areapplied in the first study. The second study is conducted by varying injection duration. Three durations are selected: 100 days, 400 days and 900 days. In miscible gas injection, miscibility and vaporization of condensate by injected gas is more efficient mechanism for condensate recovery. From this study, it is proven that the application of gas cycling on five-spot well pattern greatly enhances condensate recovery

The Huber’s Method-based Gas Concentration Reconstruction in Multicomponent Gas Mixtures from Multispectral Laser Measurements under Noise Overshoot Conditions

Directory of Open Access Journals (Sweden)

V. A. Gorodnichev

2016-01-01

Full Text Available Laser gas analysers are the most promising for the rapid quantitative analysis of gaseous air pollution. A laser gas analysis problem is that there are instable results in reconstruction of gas mixture components concentration under real noise in the recorded laser signal. This necessitates using the special processing algorithms. When reconstructing the quantitative composition of multi-component gas mixtures from the multispectral laser measurements are efficiently used methods such as Tikhonov regularization, quasi-solution search, and finding of Bayesian estimators. These methods enable using the single measurement results to determine the quantitative composition of gas mixtures under measurement noise. In remote sensing the stationary gas formations or in laboratory analysis of the previously selected (when the gas mixture is stationary air samples the reconstruction procedures under measurement noise of gas concentrations in multicomponent mixtures can be much simpler. The paper considers a problem of multispectral laser analysis of stationary gas mixtures for which it is possible to conduct a series of measurements. With noise overshoots in the recorded laser signal (and, consequently, overshoots of gas concentrations determined by a single measurement must be used stable (robust estimation techniques for substantial reducing an impact of the overshoots on the estimate of required parameters. The paper proposes the Huber method to determine gas concentrations in multicomponent mixtures under signal overshoot. To estimate the value of Huber parameter and the efficiency of Huber's method to find the stable estimates of gas concentrations in multicomponent stationary mixtures from the laser measurements the mathematical modelling was conducted. Science & Education of the Bauman MSTU 108 The mathematical modelling results show that despite the considerable difference among the errors of the mixture gas components themselves a character of

Analysis of the reactivity of sulphur compounds in petroleum cuts: kinetics and modelling of hydro-treating; Analyse de la reactivite des composes soufres dans les coupes petrolieres: cinetique et modelisation de l'hydrotraitement

Energy Technology Data Exchange (ETDEWEB)

Lopez Garcia, C.

2000-12-01

The study of the hydro-treating of middle distillates comprised the following steps: - Identification and reactivity study of the sulphur compounds present in these petroleum cuts; - Modelling of the process by a chemical kinetic approach. The hydro-treating of middle distillates is a refining process that allows elimination of organic compounds containing sulphur, nitrogen, oxygen and metals. The process also hydrogenates the aromatic compounds providing improved cetane index gas-oils while respecting the regulations that severely limit the content of sulphur compounds. The extension and the improvement of a kinetic model for the hydro-treating of LCO gas-oils (light cycle oil gas-oils) are presented in this work. In order to improve the hydro-desulfurization model predictions, a detailed identification of the sulphur compounds contained in LCO gas-oils was carried out using gas chromatography with a sulphur chemiluminescence detector (GC-SCD). The most refractory sulphur compounds (alkyl-di-benzothiophenes) were identified and lumped into different families. Based on a lumped reaction scheme with a Langmuir-Hinshelwood representation, the model takes into account the influence of temperature, total pressure and hydrogen sulphide partial pressure on the reaction rates for hydro-desulfurization, hydro-denitrogenation and hydro-de-aromatization. The model parameter estimation was based on experiments that were carried out on a micro-pilot unit using an industrial sulfided NiMo/Al{sub 2}O{sub 3} catalyst and LCO feedstocks. The analytical study of the sulphur compounds was also extended to the case of straight run gas-oils (SR). For these feedstocks, a method using high-resolution mass spectrometry coupled with gas chromatography (GC-HRMS) was developed. In this way, the kinetic model can now be extended for the SR gas-oil hydro-treating or for LCO-SR mixtures. (author)

Analysis of the reactivity of sulphur compounds in petroleum cuts: kinetics and modelling of hydro-treating; Analyse de la reactivite des composes soufres dans les coupes petrolieres: cinetique et modelisation de l'hydrotraitement

Energy Technology Data Exchange (ETDEWEB)

Lopez Garcia, C

2000-12-01

The study of the hydro-treating of middle distillates comprised the following steps: - Identification and reactivity study of the sulphur compounds present in these petroleum cuts; - Modelling of the process by a chemical kinetic approach. The hydro-treating of middle distillates is a refining process that allows elimination of organic compounds containing sulphur, nitrogen, oxygen and metals. The process also hydrogenates the aromatic compounds providing improved cetane index gas-oils while respecting the regulations that severely limit the content of sulphur compounds. The extension and the improvement of a kinetic model for the hydro-treating of LCO gas-oils (light cycle oil gas-oils) are presented in this work. In order to improve the hydro-desulfurization model predictions, a detailed identification of the sulphur compounds contained in LCO gas-oils was carried out using gas chromatography with a sulphur chemiluminescence detector (GC-SCD). The most refractory sulphur compounds (alkyl-di-benzothiophenes) were identified and lumped into different families. Based on a lumped reaction scheme with a Langmuir-Hinshelwood representation, the model takes into account the influence of temperature, total pressure and hydrogen sulphide partial pressure on the reaction rates for hydro-desulfurization, hydro-denitrogenation and hydro-de-aromatization. The model parameter estimation was based on experiments that were carried out on a micro-pilot unit using an industrial sulfided NiMo/Al{sub 2}O{sub 3} catalyst and LCO feedstocks. The analytical study of the sulphur compounds was also extended to the case of straight run gas-oils (SR). For these feedstocks, a method using high-resolution mass spectrometry coupled with gas chromatography (GC-HRMS) was developed. In this way, the kinetic model can now be extended for the SR gas-oil hydro-treating or for LCO-SR mixtures. (author)

An Excel tool for deriving key photosynthetic parameters from combined gas exchange and chlorophyll fluorescence: theory and practice.

Science.gov (United States)

Bellasio, Chandra; Beerling, David J; Griffiths, Howard

2016-06-01

Combined photosynthetic gas exchange and modulated fluorometres are widely used to evaluate physiological characteristics associated with phenotypic and genotypic variation, whether in response to genetic manipulation or resource limitation in natural vegetation or crops. After describing relatively simple experimental procedures, we present the theoretical background to the derivation of photosynthetic parameters, and provide a freely available Excel-based fitting tool (EFT) that will be of use to specialists and non-specialists alike. We use data acquired in concurrent variable fluorescence-gas exchange experiments, where A/Ci and light-response curves have been measured under ambient and low oxygen. From these data, the EFT derives light respiration, initial PSII (photosystem II) photochemical yield, initial quantum yield for CO2 fixation, fraction of incident light harvested by PSII, initial quantum yield for electron transport, electron transport rate, rate of photorespiration, stomatal limitation, Rubisco (ribulose 1·5-bisphosphate carboxylase/oxygenase) rate of carboxylation and oxygenation, Rubisco specificity factor, mesophyll conductance to CO2 diffusion, light and CO2 compensation point, Rubisco apparent Michaelis-Menten constant, and Rubisco CO2 -saturated carboxylation rate. As an example, a complete analysis of gas exchange data on tobacco plants is provided. We also discuss potential measurement problems and pitfalls, and suggest how such empirical data could subsequently be used to parameterize predictive photosynthetic models. © 2015 John Wiley & Sons Ltd.

Development of a macro-element by condensation, shown for the load categories of aircraft crash and seismic events, for soil-structure interaction in the case of flexible foundation

International Nuclear Information System (INIS)

Matthees, W.

1989-01-01

This report presents the results of a three-dimensional model developed for the analysis of soil-structure interaction problems. The realistic treatment of the stiffness for the foundation plate avoids the restriction of lumped parameter models for one-dimensional beam-models with a rigid plate or for multi-dimensional models with distributed lumped parameters. The soil-behaviour is defined by the condensation of a limited soil section, called macro-element. An improved matrix radiation damping comparable with lumped parameters is resultant from the condensation of viscous dampers, situated along the boundaries of the soil section. The finess of discretization is similar for the soil and for the structure. The method is presented in the time domain for a linear axisymmetric code with lumped mass having a consistent mass coupling of the macro-element. By application of the macro-element a realistic three-dimensional system may be analyzed with a reasonable numerical effort. (orig.) With 80 figs., 3 tabs [de

A local leaky-box model for the local stellar surface density-gas surface density-gas phase metallicity relation

Science.gov (United States)

Zhu, Guangtun Ben; Barrera-Ballesteros, Jorge K.; Heckman, Timothy M.; Zakamska, Nadia L.; Sánchez, Sebastian F.; Yan, Renbin; Brinkmann, Jonathan

2017-07-01

We revisit the relation between the stellar surface density, the gas surface density and the gas-phase metallicity of typical disc galaxies in the local Universe with the SDSS-IV/MaNGA survey, using the star formation rate surface density as an indicator for the gas surface density. We show that these three local parameters form a tight relationship, confirming previous works (e.g. by the PINGS and CALIFA surveys), but with a larger sample. We present a new local leaky-box model, assuming star-formation history and chemical evolution is localized except for outflowing materials. We derive closed-form solutions for the evolution of stellar surface density, gas surface density and gas-phase metallicity, and show that these parameters form a tight relation independent of initial gas density and time. We show that, with canonical values of model parameters, this predicted relation match the observed one well. In addition, we briefly describe a pathway to improving the current semi-analytic models of galaxy formation by incorporating the local leaky-box model in the cosmological context, which can potentially explain simultaneously multiple properties of Milky Way-type disc galaxies, such as the size growth and the global stellar mass-gas metallicity relation.

Thermodynamic modelling of acid gas removal from natural gas using the Extended UNIQUAC model

DEFF Research Database (Denmark)

Sadegh, Negar; Stenby, Erling Halfdan; Thomsen, Kaj

2017-01-01

Thermodynamics of natural gas sweetening process needs to be known for proper design of natural gas treating plants. Absorption with aqueous N-Methyldiethanolamine is currently the most commonly used process for removal of acid gas (CO2 and H2S) impurities from natural gas. Model parameters...... for the Extended UNIQUAC model have already been determined by the same authors to calculate single acid gas solubility in aqueous MDEA. In this study, the model is further extended to estimate solubility of CO2 and H2S and their mixture in aqueous MDEA at high pressures with methane as a makeup gas....

On plasma-neutral gas interaction

International Nuclear Information System (INIS)

Venkataramani, N.; Mattoo, S.K.

1980-01-01

The importance of plasma-neutral gas interaction layer has been emphasized by pointing out its application to a wide variety of physical phenomena. The interaction of a magnetised plasma stream penetrating a neutral gas cloud is discussed in the light of Alfven's critical velocity and Varma's threshold velocity on the ionising interaction. Interaction of a moving magnetised plasma with a stationary neutral gas has been studied and described. The device comprises of a plasma gun and an interaction region where neutral gas cloud is injected. The interaction region is provided with a transverse magnetic field of upto 1000 G. Several diagnostics deployed at the interaction region to make measurements on the macroscopic parameters of plasma and neutral gas are described. The parameters of discharge circuits are measured with high current and voltage probes. An interaction between a magnetised plasma stream and a neutral gas cloud is demonstrated. It is shown that this interaction does not have Varma's threshold on their relative velocity. The Alfven's critical velocity phenomenon is shown to depend on the integrated column neutral gas density that a plasma stream encounters while penetrating through it and not on the neutral gas density in the range of 10 17 -10 21 m -3 . (auth.)

Sensitivity analysis of respiratory parameter uncertainties: impact of criterion function form and constraints.

Science.gov (United States)

Lutchen, K R

1990-08-01

A sensitivity analysis based on weighted least-squares regression is presented to evaluate alternative methods for fitting lumped-parameter models to respiratory impedance data. The goal is to maintain parameter accuracy simultaneously with practical experiment design. The analysis focuses on predicting parameter uncertainties using a linearized approximation for joint confidence regions. Applications are with four-element parallel and viscoelastic models for 0.125- to 4-Hz data and a six-element model with separate tissue and airway properties for input and transfer impedance data from 2-64 Hz. The criterion function form was evaluated by comparing parameter uncertainties when data are fit as magnitude and phase, dynamic resistance and compliance, or real and imaginary parts of input impedance. The proper choice of weighting can make all three criterion variables comparable. For the six-element model, parameter uncertainties were predicted when both input impedance and transfer impedance are acquired and fit simultaneously. A fit to both data sets from 4 to 64 Hz could reduce parameter estimate uncertainties considerably from those achievable by fitting either alone. For the four-element models, use of an independent, but noisy, measure of static compliance was assessed as a constraint on model parameters. This may allow acceptable parameter uncertainties for a minimum frequency of 0.275-0.375 Hz rather than 0.125 Hz. This reduces data acquisition requirements from a 16- to a 5.33- to 8-s breath holding period. These results are approximations, and the impact of using the linearized approximation for the confidence regions is discussed.

Modelling of intermittent microwave convective drying: parameter sensitivity

Directory of Open Access Journals (Sweden)

Zhang Zhijun

2017-06-01

Full Text Available The reliability of the predictions of a mathematical model is a prerequisite to its utilization. A multiphase porous media model of intermittent microwave convective drying is developed based on the literature. The model considers the liquid water, gas and solid matrix inside of food. The model is simulated by COMSOL software. Its sensitivity parameter is analysed by changing the parameter values by ±20%, with the exception of several parameters. The sensitivity analysis of the process of the microwave power level shows that each parameter: ambient temperature, effective gas diffusivity, and evaporation rate constant, has significant effects on the process. However, the surface mass, heat transfer coefficient, relative and intrinsic permeability of the gas, and capillary diffusivity of water do not have a considerable effect. The evaporation rate constant has minimal parameter sensitivity with a ±20% value change, until it is changed 10-fold. In all results, the temperature and vapour pressure curves show the same trends as the moisture content curve. However, the water saturation at the medium surface and in the centre show different results. Vapour transfer is the major mass transfer phenomenon that affects the drying process.

Effectiveness of the Stewart Method in the Evaluation of Blood Gas Parameters.

Science.gov (United States)

Gezer, Mustafa; Bulucu, Fatih; Ozturk, Kadir; Kilic, Selim; Kaldirim, Umit; Eyi, Yusuf Emrah

2015-03-01

In 1981, Peter A. Stewart published a paper describing his concept for employing Strong Ion Difference. In this study we compared the HCO3 levels and Anion Gap (AG) calculated using the classic method and the Stewart method. Four hundred nine (409) arterial blood gases of 90 patients were collected retrospectively. Some were obtained from the same patients in different times and conditions. All blood samples were evaluated using the same device (ABL 800 Blood Gas Analyzer). HCO3 level and AG were calculated using the Stewart method via the website AcidBase.org. HCO3 levels, AG and strong ion difference (SID) were calculated using the Stewart method, incorporating the parameters of age, serum lactate, glucose, sodium, and pH, etc. According to classic method, the levels of HCO3 and AG were 22.4±7.2 mEq/L and 20.1±4.1 mEq/L respectively. According to Stewart method, the levels of HCO3 and AG were 22.6±7.4 and 19.9±4.5 mEq/L respectively. There was strong correlation between the classic method and the Stewart method for calculating HCO3 and AG. The Stewart method may be more effective in the evaluation of complex metabolic acidosis.

Monitoring gas quality green gas feeding in; Monitoring gaskwaliteit groengasinvoeding

Energy Technology Data Exchange (ETDEWEB)

Holstein, J. [DNV KEMA Energy and Sustainability, Arnhem (Netherlands); Polman, E. [Kiwa Technology, Apeldoorn (Netherlands)

2013-04-15

Due to the growing number of green gas facilities in the Netherlands more practical knowledge is collected about the production and injection of green gas. Also there was the need to gather data about more practical experiences and knowledge about the gas quality, the performance of gas cleaning and gas treatment systems, as well the integration of green gas in the gas infrastructure. In addition to this, there is a need to get insight in the safety aspects of green gas injection. In order to comply this demand, DNV KEMA en Kiwa Technology measured the quality parameters continuously between June 2012 en January 2013 (three weeks) and discontinuously (gas samples) of green gas at eight production facilities. The measurements have been performed at designated places and are independent from the measurements of the biomethane producer. In order to be sure that the results of DNV KEMA and Kiwa are comparable, a combined measurement program was executed. It results in uniformity for all the measured values: the differences are within the uncertainty level for each component. During the measurement period of three weeks, the gas quality parameters were compared to specifications, written down in the national regulations for the transport and the distribution grid respectively [Dutch] Door het groeiend aantal groengasinvoedingen in Nederland wordt steeds meer praktijkkennis verzameld. Er dient meer praktijkkennis te worden verzameld over de chemische gaskwaliteit, prestaties van de gasreiniging- en gasopwaardering en de wijze van inpassing in de bestaande infrastructuur. Daarnaast is het wenselijk om inzicht te verkrijgen in de veiligheid van groengasinvoeding. Daarop is de groengaskwaliteit op acht locaties over een periode van drie weken continu en discontinu gemeten tussen juni 2012 en januari 2013. De metingen zijn uitgevoerd op een aangewezen plaats door de netbeheerder en staan los van de metingen van de invoeders zelf. Voor het waarborgen van de uniformiteit van

Assisting Gas Optimization in CO2 Laser Welding

DEFF Research Database (Denmark)

Gong, Hui; Olsen, Flemming Ove

1996-01-01

High quality laser welding is achieved under the condition of optimizing all process parameters. Assisting gas plays an important role for sound welds. In the conventional welding process assisting gas is used as a shielding gas to prevent that the weld seam oxidates. In the laser welding process...... assisting gas is also needed to control the laser induced plasma.Assisting gas is one of the most important parameters in the laser welding process. It is responsible for obtaining a quality weld which is characterized by deep penetration, no interior imperfections, i.e. porosity, no crack, homogeneous seam...... surface, etc. In this work a specially designed flexible off-axis nozzle capable of adjusting the angle of the nozzle, the diameter of the nozzle, and the distance between the nozzle end and the welding zone is tested. In addition to the nozzle parameters three gases, Nitrogen, Argon, and Helium...

On-line analysis of hydrogen and other parameters in the mineral and energy industries

International Nuclear Information System (INIS)

Sowerby, B.D.

1998-01-01

The objective of the project is the development and industrial application of nuclear and microwave techniques for the on-line determination of hydrogen, moisture and other parameters. This document presents progress with respect to the stated objectives. A laboratory feasibility study has been carried out on new and advanced neutron and gamma ray analysis systems for the direct on-conveyor belt analysis of ash in coal. Neutron inelastic scattering and thermal neutron capture gamma ray technique were used in development of an on-belt elemental analyser for cement industry. Microwave based technology has been developed for on-conveyor belt determination of moisture in coal. A fast neutron and gamma-ray transmission technique has been applied for on-belt determination of moisture in lump coke

A CPW-Fed Quasi-PIFA Antenna Using Quasi-Lumped Resonators for Mobile Phones

Directory of Open Access Journals (Sweden)

Majid Rafiee

2015-01-01

Full Text Available A novel single CPW-fed Quasi-Planar Inverted-F Antenna (PIFA using quasi-lumped elements is developed for mobile communication handheld terminals operating at 2.6 GHz. The antenna is composed of an inductor covered by a set of interdigital and parasitic capacitors. The proposed antenna achieves a measured bandwidth of 11% for return loss with the antenna gain of about 4 dBi. The antenna is designed in single layer (zero height which is appropriate to be used in thin devices where a small room is considered for the antenna. The proposed antenna is suitable for use in Long Term Evolution band 7. The operating frequency of introduced antenna depends on the number of interdigital fingers and inductor length rather than the total resonator patch only, so that the operating frequency can be altered while the total patch size remains unchanged. The calculated operating frequency is confirmed by simulation and measurement. Also the dipole-like simulated radiation pattern is confirmed by measurement.

The Solubility Parameters of Ionic Liquids

Science.gov (United States)

Marciniak, Andrzej

2010-01-01

The Hildebrand’s solubility parameters have been calculated for 18 ionic liquids from the inverse gas chromatography measurements of the activity coefficients at infinite dilution. Retention data were used for the calculation. The solubility parameters are helpful for the prediction of the solubility in the binary solvent mixtures. From the solubility parameters, the standard enthalpies of vaporization of ionic liquids were estimated. PMID:20559495

The Solubility Parameters of Ionic Liquids

Directory of Open Access Journals (Sweden)

Andrzej Marciniak

2010-04-01

Full Text Available The Hildebrand’s solubility parameters have been calculated for 18 ionic liquids from the inverse gas chromatography measurements of the activity coefficients at infinite dilution. Retention data were used for the calculation. The solubility parameters are helpful for the prediction of the solubility in the binary solvent mixtures. From the solubility parameters, the standard enthalpies of vaporization of ionic liquids were estimated.

Depletion optimization of lumped burnable poisons in pressurized water reactors

International Nuclear Information System (INIS)

Kodah, Z.H.

1982-01-01

Techniques were developed to construct a set of basic poison depletion curves which deplete in a monotonical manner. These curves were combined to match a required optimized depletion profile by utilizing either linear or non-linear programming methods. Three computer codes, LEOPARD, XSDRN, and EXTERMINATOR-2 were used in the analyses. A depletion routine was developed and incorporated into the XSDRN code to allow the depletion of fuel, fission products, and burnable poisons. The Three Mile Island Unit-1 reactor core was used in this work as a typical PWR core. Two fundamental burnable poison rod designs were studied. They are a solid cylindrical poison rod and an annular cylindrical poison rod with water filling the central region.These two designs have either a uniform mixture of burnable poisons or lumped spheroids of burnable poisons in the poison region. Boron and gadolinium are the two burnable poisons which were investigated in this project. Thermal self-shielding factor calculations for solid and annular poison rods were conducted. Also expressions for overall thermal self-shielding factors for one or more than one size group of poison spheroids inside solid and annular poison rods were derived and studied. Poison spheroids deplete at a slower rate than the poison mixture because each spheroid exhibits some self-shielding effects of its own. The larger the spheroid, the higher the self-shielding effects due to the increase in poison concentration

Influences of pulsed current tungsten inert gas welding parameters on the tensile properties of AA 6061 aluminium alloy

International Nuclear Information System (INIS)

Senthil Kumar, T.; Balasubramanian, V.; Sanavullah, M.Y.

2007-01-01

Medium strength aluminium alloy (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. In any structural application of this alloy consideration its weldability is of utmost importance as welding is largely used for joining of structural components. The preferred welding process of aluminium alloy is frequently tungsten inert gas (TIG) welding due to its comparatively easier applicability and better economy. In the case of single pass TIG welding of thinner section of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current process. The use of pulsed current parameters has been found to improve the mechanical properties of the welds compared to those of continuous current welds of this alloy due to grain refinement occurring in the fusion zone. Many considerations come into the picture and one need to carefully balance various pulse current parameters to arrive at an optimum combination. Hence, in this investigation an attempt has been made to study the influence of pulsed current TIG welding parameters on tensile properties of AA 6061 aluminium alloy weldments

Dynamical vanishing of the order parameter in a confined Bardeen-Cooper-Schrieffer Fermi gas after an interaction quench

Science.gov (United States)

Hannibal, S.; Kettmann, P.; Croitoru, M. D.; Axt, V. M.; Kuhn, T.

2018-01-01

We present a numerical study of the Higgs mode in an ultracold confined Fermi gas after an interaction quench and find a dynamical vanishing of the superfluid order parameter. Our calculations are done within a microscopic density-matrix approach in the Bogoliubov-de Gennes framework which takes the three-dimensional cigar-shaped confinement explicitly into account. In this framework, we study the amplitude mode of the order parameter after interaction quenches starting on the BCS side of the BEC-BCS crossover close to the transition and ending in the BCS regime. We demonstrate the emergence of a dynamically vanishing superfluid order parameter in the spatiotemporal dynamics in a three-dimensional trap. Further, we show that the signal averaged over the whole trap mirrors the spatiotemporal behavior and allows us to systematically study the effects of the system size and aspect ratio on the observed dynamics. Our analysis enables us to connect the confinement-induced modifications of the dynamics to the pairing properties of the system. Finally, we demonstrate that the signature of the Higgs mode is contained in the dynamical signal of the condensate fraction, which, therefore, might provide a new experimental access to the nonadiabatic regime of the Higgs mode.

Impact of Endogenous and Exogenous Interferences on Clinical Chemistry Parameters Measured on Blood Gas Analyzers.

Science.gov (United States)

Grieme, Caleb V; Voss, Dena R; Davis, Scott R; Krasowski, Matthew D

2017-03-01

The prevalence of hemolysis, icterus, and lipemia (HIL) was determined for residual whole blood specimens analyzed for clinical chemistry parameters on blood gas analyzers. The frequency and potential impact of exogenous interference from iodide, salicylate, and thiocyanate (metabolite of sodium nitroprusside) on analysis of whole blood chloride was also assessed. Over an approximately two month period at an academic medical center, indices for HIL were determined on Roche cobas c502 analyzers for 1,986 residual whole blood specimens that had been previously analyzed for clinical chemistry parameters on Radiometer ABL90 FLEX blood gas analyzers. To examine exogenous interferences, retrospective analysis was performed over multiple years to ascertain whether patient samples analyzed for whole blood chloride were potentially affected by interference from iodide, salicylate, or thiocyanate. Some degree of hemolysis (defined as hemolysis index of greater than 60) was present in 9.7% of the whole blood specimens. Increasing rates of hemolysis were associated with higher whole blood potassium concentrations. Nearly 60% of specimens with potassium concentrations between 6.0 and 6.9 mEq/L had hemolysis indices of 100 or greater, and 75% of specimens with a potassium concentration of 7.0 mEq/L or greater were severely hemolyzed (hemolysis index of 300 or greater). In contrast to the hemolysis results, icterus and lipemia were determined to have minimal impact on patient results. For the exogenous interferences, we did not identify any patient samples where elevated salicylate levels or pharmaceutical iodide administration overlapped with whole blood chloride analysis (out of 75,887 and 169,229 total chloride measurements, respectively). We did, however, find that for patients receiving nitroprusside therapy in the inpatient setting, whole blood chloride concentrations were significantly higher during nitroprusside therapy [106.7 +/- 6.2 mEq/L (mean, SD)] compared to before

Selected parameters of maize straw briquettes combustion

Directory of Open Access Journals (Sweden)

Kraszkiewicz Artur

2018-01-01

Full Text Available An analysis of the process of burning briquettes made of maize straw was performed. A number of traits have been evaluated, including physical characteristics of the fuel through parameters describing combustion kinetics as well as products and combustion efficiency. The study was conducted in a grate boiler, during which the differentiating factor was the air velocity flowing to the boiler. It was observed that the obtained values of the considered parameters were different, particularly temperature of the flue gas and the amount of CO and SO2 in the flue gas.

Assessing the accuracy of subject-specific, muscle-model parameters determined by optimizing to match isometric strength.

Science.gov (United States)

DeSmitt, Holly J; Domire, Zachary J

2016-12-01

Biomechanical models are sensitive to the choice of model parameters. Therefore, determination of accurate subject specific model parameters is important. One approach to generate these parameters is to optimize the values such that the model output will match experimentally measured strength curves. This approach is attractive as it is inexpensive and should provide an excellent match to experimentally measured strength. However, given the problem of muscle redundancy, it is not clear that this approach generates accurate individual muscle forces. The purpose of this investigation is to evaluate this approach using simulated data to enable a direct comparison. It is hypothesized that the optimization approach will be able to recreate accurate muscle model parameters when information from measurable parameters is given. A model of isometric knee extension was developed to simulate a strength curve across a range of knee angles. In order to realistically recreate experimentally measured strength, random noise was added to the modeled strength. Parameters were solved for using a genetic search algorithm. When noise was added to the measurements the strength curve was reasonably recreated. However, the individual muscle model parameters and force curves were far less accurate. Based upon this examination, it is clear that very different sets of model parameters can recreate similar strength curves. Therefore, experimental variation in strength measurements has a significant influence on the results. Given the difficulty in accurately recreating individual muscle parameters, it may be more appropriate to perform simulations with lumped actuators representing similar muscles.

Distribution-centric 3-parameter thermodynamic models of partition gas chromatography.

Science.gov (United States)

Blumberg, Leonid M

2017-03-31

If both parameters (the entropy, ΔS, and the enthalpy, ΔH) of the classic van't Hoff model of dependence of distribution coefficients (K) of analytes on temperature (T) are treated as the temperature-independent constants then the accuracy of the model is known to be insufficient for the needed accuracy of retention time prediction. A more accurate 3-parameter Clarke-Glew model offers a way to treat ΔS and ΔH as functions, ΔS(T) and ΔH(T), of T. A known T-centric construction of these functions is based on relating them to the reference values (ΔS ref and ΔH ref ) corresponding to a predetermined reference temperature (T ref ). Choosing a single T ref for all analytes in a complex sample or in a large database might lead to practically irrelevant values of ΔS ref and ΔH ref for those analytes that have too small or too large retention factors at T ref . Breaking all analytes in several subsets each with its own T ref leads to discontinuities in the analyte parameters. These problems are avoided in the K-centric modeling where ΔS(T) and ΔS(T) and other analyte parameters are described in relation to their values corresponding to a predetermined reference distribution coefficient (K Ref ) - the same for all analytes. In this report, the mathematics of the K-centric modeling are described and the properties of several types of K-centric parameters are discussed. It has been shown that the earlier introduced characteristic parameters of the analyte-column interaction (the characteristic temperature, T char , and the characteristic thermal constant, θ char ) are a special chromatographically convenient case of the K-centric parameters. Transformations of T-centric parameters into K-centric ones and vice-versa as well as the transformations of one set of K-centric parameters into another set and vice-versa are described. Copyright © 2017 Elsevier B.V. All rights reserved.

Neutronic of heterogenous gas cooled reactors

International Nuclear Information System (INIS)

Maturana, Roberto Hernan

2008-01-01

At present, one of the main technical features of the advanced gas cooled reactor under development is its fuel element concept, which implies a neutronic homogeneous design, thus requiring higher enrichment compared with present commercial nuclear power plants.In this work a neutronic heterogeneous gas cooled reactor design is analyzed by studying the neutronic design of the Advanced Gas cooled Reactor (AGR), a low enrichment, gas cooled and graphite moderated nuclear power plant.A search of merit figures (some neutronic parameter, characteristic dimension, or a mixture of both) which are important and have been optimized during the reactor design stage is been done, to aim to comprise how a gas heterogeneous reactor is been design, given that semi-infinity arrangement criteria of rods in LWRs and clusters in HWRs can t be applied for a solid moderator and a gas refrigerator.The WIMS code for neutronic cell calculations is been utilized to model the AGR fuel cell and to calculate neutronic parameters such as the multiplication factor and the pick factor, as function of the fuel burnup.Also calculation is been done for various nucleus characteristic dimensions values (fuel pin radius, fuel channel pitch) and neutronic parameters (such as fuel enrichment), around the design established parameters values.A fuel cycle cost analysis is carried out according to the reactor in study, and the enrichment effect over it is been studied.Finally, a thermal stability analysis is been done, in subcritical condition and at power level, to study this reactor characteristic reactivity coefficients.Present results shows (considering the approximation used) a first set of neutronic design figures of merit consistent with the AGR design. [es

Deriving C4 photosynthetic parameters from combined gas exchange and chlorophyll fluorescence using an Excel tool: theory and practice.

Science.gov (United States)

Bellasio, Chandra; Beerling, David J; Griffiths, Howard

2016-06-01

The higher photosynthetic potential of C4 plants has led to extensive research over the past 50 years, including C4 -dominated natural biomes, crops such as maize, or for evaluating the transfer of C4 traits into C3 lineages. Photosynthetic gas exchange can be measured in air or in a 2% Oxygen mixture using readily available commercial gas exchange and modulated PSII fluorescence systems. Interpretation of these data, however, requires an understanding (or the development) of various modelling approaches, which limit the use by non-specialists. In this paper we present an accessible summary of the theory behind the analysis and derivation of C4 photosynthetic parameters, and provide a freely available Excel Fitting Tool (EFT), making rigorous C4 data analysis accessible to a broader audience. Outputs include those defining C4 photochemical and biochemical efficiency, the rate of photorespiration, bundle sheath conductance to CO2 diffusion and the in vivo biochemical constants for PEP carboxylase. The EFT compares several methodological variants proposed by different investigators, allowing users to choose the level of complexity required to interpret data. We provide a complete analysis of gas exchange data on maize (as a model C4 organism and key global crop) to illustrate the approaches, their analysis and interpretation. © 2015 John Wiley & Sons Ltd. © 2016 John Wiley & Sons Ltd.

Stochastic lumping analysis for linear kinetics and its application to the fluctuation relations between hierarchical kinetic networks

Energy Technology Data Exchange (ETDEWEB)

Deng, De-Ming; Chang, Cheng-Hung [Institute of Physics, National Chiao Tung University, Hsinchu 300, Taiwan (China)

2015-05-14

Conventional studies of biomolecular behaviors rely largely on the construction of kinetic schemes. Since the selection of these networks is not unique, a concern is raised whether and under which conditions hierarchical schemes can reveal the same experimentally measured fluctuating behaviors and unique fluctuation related physical properties. To clarify these questions, we introduce stochasticity into the traditional lumping analysis, generalize it from rate equations to chemical master equations and stochastic differential equations, and extract the fluctuation relations between kinetically and thermodynamically equivalent networks under intrinsic and extrinsic noises. The results provide a theoretical basis for the legitimate use of low-dimensional models in the studies of macromolecular fluctuations and, more generally, for exploring stochastic features in different levels of contracted networks in chemical and biological kinetic systems.

Stochastic lumping analysis for linear kinetics and its application to the fluctuation relations between hierarchical kinetic networks.

Science.gov (United States)

Deng, De-Ming; Chang, Cheng-Hung

2015-05-14

Conventional studies of biomolecular behaviors rely largely on the construction of kinetic schemes. Since the selection of these networks is not unique, a concern is raised whether and under which conditions hierarchical schemes can reveal the same experimentally measured fluctuating behaviors and unique fluctuation related physical properties. To clarify these questions, we introduce stochasticity into the traditional lumping analysis, generalize it from rate equations to chemical master equations and stochastic differential equations, and extract the fluctuation relations between kinetically and thermodynamically equivalent networks under intrinsic and extrinsic noises. The results provide a theoretical basis for the legitimate use of low-dimensional models in the studies of macromolecular fluctuations and, more generally, for exploring stochastic features in different levels of contracted networks in chemical and biological kinetic systems.

Applying probabilistic well-performance parameters to assessments of shale-gas resources

Science.gov (United States)

Charpentier, Ronald R.; Cook, Troy

2010-01-01

In assessing continuous oil and gas resources, such as shale gas, it is important to describe not only the ultimately producible volumes, but also the expected well performance. This description is critical to any cost analysis or production scheduling. A probabilistic approach facilitates (1) the inclusion of variability in well performance within a continuous accumulation, and (2) the use of data from developed accumulations as analogs for the assessment of undeveloped accumulations. In assessing continuous oil and gas resources of the United States, the U.S. Geological Survey analyzed production data from many shale-gas accumulations. Analyses of four of these accumulations (the Barnett, Woodford, Fayetteville, and Haynesville shales) are presented here as examples of the variability of well performance. For example, the distribution of initial monthly production rates for Barnett vertical wells shows a noticeable change with time, first increasing because of improved completion practices, then decreasing from a combination of decreased reservoir pressure (in infill wells) and drilling in less productive areas. Within a partially developed accumulation, historical production data from that accumulation can be used to estimate production characteristics of undrilled areas. An understanding of the probabilistic relations between variables, such as between initial production and decline rates, can improve estimates of ultimate production. Time trends or spatial trends in production data can be clarified by plots and maps. The data can also be divided into subsets depending on well-drilling or well-completion techniques, such as vertical in relation to horizontal wells. For hypothetical or lightly developed accumulations, one can either make comparisons to a specific well-developed accumulation or to the entire range of available developed accumulations. Comparison of the distributions of initial monthly production rates of the four shale-gas accumulations that were

Internal Combustion Engine Powered by Synthesis Gas from Pyrolysed Plastics

Directory of Open Access Journals (Sweden)

Chríbik Andrej

2016-07-01

Full Text Available The article discusses the application of synthesis gas from pyrolysis of plastics in petrol engine. The appropriate experimental measurements were performed on a combustion engine LGW 702 designated for micro-cogeneration unit. The power parameters, economic parameters in term of brake specific fuel consumption, and internal parameters of the engine were compared to the engine running on the reference fuel - natural gas and synthesis gas. Burning synthesis gas leads to decreased performance by about 5% and to increased mass hourly consumption by 120 %. In terms of burning, synthesis gas has similar properties as natural gas. Compared with [5] a more detailed study has been prepared on the effects of angle of spark advance on the engine torque, giving more detailed assessment of engine cycle variability and considering specification of start and end of combustion in the logarithm p-V diagram.

Assessment of thermodynamic parameters of plasma shock wave

International Nuclear Information System (INIS)

Vasileva, O V; Isaev, Yu N; Budko, A A; Filkov, A I

2014-01-01

The work is devoted to the solution of the one-dimensional equation of hydraulic gas dynamics for the coaxial magneto plasma accelerator by means of Lax-Wendroff modified algorithm with optimum choice of the regularization parameter artificial viscosity. Replacement of the differential equations containing private derivatives is made by finite difference method. Optimum parameter of regularization artificial viscosity is added using the exact known decision of Soda problem. The developed algorithm of thermodynamic parameter calculation in a braking point is proved. Thermodynamic parameters of a shock wave in front of the plasma piston of the coaxial magneto plasma accelerator are calculated on the basis of the offered algorithm. Unstable high-frequency fluctuations are smoothed using modeling and that allows narrowing the ambiguity area. Results of calculation of gas dynamic parameters in a point of braking coincide with literary data. The chart 3 shows the dynamics of change of speed and thermodynamic parameters of a shock wave such as pressure, density and temperature just before the plasma piston

Optimizing parameters of GTU cycle and design values of air-gas channel in a gas turbine with cooled nozzle and rotor blades

Science.gov (United States)

Kler, A. M.; Zakharov, Yu. B.

2012-09-01

The authors have formulated the problem of joint optimization of pressure and temperature of combustion products before gas turbine, profiles of nozzle and rotor blades of gas turbine, and cooling air flow rates through nozzle and rotor blades. The article offers an original approach to optimization of profiles of gas turbine blades where the optimized profiles are presented as linear combinations of preliminarily formed basic profiles. The given examples relate to optimization of the gas turbine unit on the criterion of power efficiency at preliminary heat removal from air flows supplied for the air-gas channel cooling and without such removal.

Determination of gold in lump by the gamma-activation analysis method

International Nuclear Information System (INIS)

Yantsen, V.A.; Ermakov, K.S.

2006-01-01

Full text: In the report the installation is described used in the Central gamma-activation analysis laboratory (CGAAL) for express quantitative determination of gold concentration in large powdered samples. The method of gold contents determination for non-crushed samples (pieces up to 100 mm). The given gamma-activation analysis method is widely used in mining industry, and at researches related with selection of optimal technological circuits designed for sorting the pieces of ore and rock materials. By developing this method it is now possible to create the technological collection of separated pieces by size, large by the amount of samples, imitating various sorts (by gold concentration in them) and types (by elemental composition) ores, and, based on these collection, to compare the efficiencies of various enrichment methods by knowing in advance the concentrations of gold in these lumps being the final sorting products. The Gamma-activation analysis method of large pieces is mainly used as foundation for the x-ray radiometric (XRR) method of pieces separation of gold-bearing ores from the deposits mined by the Navoi mining combine. It allows significant increase in the rate of research and development works on selection of the most reliable separation characteristics. Based on these one can develop optimal technological circuits for ore enrichment with portion sorting methods. (author)

The High Level Mathematical Models in Calculating Aircraft Gas Turbine Engine Parameters

Directory of Open Access Journals (Sweden)

Yu. A. Ezrokhi

2017-01-01

Full Text Available The article describes high-level mathematical models developed to solve special problems arising at later stages of design with regard to calculation of the aircraft gas turbine engine (GTE under real operating conditions. The use of blade row mathematics models, as well as mathematical models of a higher level, including 2D and 3D description of the working process in the engine units and components, makes it possible to determine parameters and characteristics of the aircraft engine under conditions significantly different from the calculated ones.The paper considers application of mathematical modelling methods (MMM for solving a wide range of practical problems, such as forcing the engine by injection of water into the flowing part, estimate of the thermal instability effect on the GTE characteristics, simulation of engine start-up and windmill starting condition, etc. It shows that the MMM use, when optimizing the laws of the compressor stator control, as well as supplying cooling air to the hot turbine components in the motor system, can significantly improve the integral traction and economic characteristics of the engine in terms of its gas-dynamic stability, reliability and resource.It ought to bear in mind that blade row mathematical models of the engine are designed to solve purely "motor" problems and do not replace the existing models of various complexity levels used in calculation and design of compressors and turbines, because in “quality” a description of the working processes in these units is inevitably inferior to such specialized models.It is shown that the choice of the mathematical modelling level of an aircraft engine for solving a particular problem arising in its designing and computational study is to a large extent a compromise problem. Despite the significantly higher "resolution" and information ability the motor mathematical models containing 2D and 3D approaches to the calculation of flow in blade machine

Switching a gas detector types misromegas

International Nuclear Information System (INIS)

Hafsi, Marwa; Gannouni, Sonia

2010-01-01

Micromegas is a gas enclosure made up of two stages separated by a micro grille: the first volume of gas, 2 cm is limited by cathode and the micro grille, is the space of conversion or of drift where are creating the primary electron-ion pairs. The second volume, 100 μ m limited by the micro grille and the plan of conduction (anode), is the space of amplification which with the function to amplify the electrons by phenomenon d' avalanche. The function of this type of detector rests on various physical parameters which come into play: speed of drift of the electrons in gas, space and temporal resolution, attachment The simulations allow studying these parameters to optimize the operation of the detector by choosing a good compromise, in particular with regard to the composition of gas. Two simulation programs used to understand certain physical phenomena (configuration of the field electric in the detector, properties of transport of the electrons in gas) are Garfield and Magboltz.

Gas target neutron generator studies

International Nuclear Information System (INIS)

Chatoorgoon, V.

1978-01-01

The need for an intense neutron source for the study of radiation damage on materials has resulted in the proposal of various solid, liquid, and gas targets. Among the gas targets proposed have been the transonic gas target, two types of hypersonic gas target, and the subsonic gas target (SGT). It has been suggested that heat deposition in a subsonic channel might create a gas density step which would constitute an attractive gas target type. The first part of the present study examines this aspect of the SGT and shows that gas density gradients are indeed formed by heat deposition in subsonic flow. The variation of beam voltage, gas density, gas pressure, and gas temperature within the channel have been calculated as functions of the system parameters: beam voltage, beam current, channel diameter, stagnation tank temperature and pressure. The analysis is applicable to any beam particle and target gas. For the case of T + on D 2 , which is relevant to the fusion application, the 14 MeV neutron profiles are presented as a function of system parameters. It is found that the SGT is compatible with concentrated intense source operation. The possibility of instability was investigated in detail using a non-linear analysis which made it possible to follow the complete time development of the SGT. It was found that the SGT is stable against all small perturbations and certain types of large perturbations. It appears that the SGT is the most advantageous type of gas target, operating at a lower mass flow and less severe stagnation tank conditions than the other types. The second part of the thesis examines a problem associated with the straight hypersonic target, the deuterium spill into the tritium port. The regime of practical operation for this target is established. (auth)

Inverse modeling for the determination of hydrogeological parameters of a two-phase system

International Nuclear Information System (INIS)

Finsterle, S.

1993-02-01

Investigations related to the disposal of radioactive wastes in Switzerland consider formations containing natural gas as potential rocks for a repository. Moreover, gas generation in the repository itself may lead to an unsaturated zone of significant extent and impact on the system's performance. The site characterization procedure requires the estimation of hydraulic properties being used as input parameters for a two-phase two-component numerical simulator. In this study, estimates of gas-related formation parameters are obtained by inverse modeling. Based on discrete observations of the system's state, model parameters can be estimated within the framework of a given conceptual model by means of optimization techniques. This study presents the theoretical background that related field data to the model parameters. A parameter estimation procedure is proposed and implemented in a computer code for automatic model calibration. This tool allows identification of key parameters affecting flow of water and gas in porous media. The inverse modeling approach is verified using data from a synthetic laboratory experiment. In addition, the Gas test performed at the Grimsel Test Site is analyzed in order to demonstrate the applicability of the proposed procedure when used with data from a real geologic environment. Estimation of hydrogeologic parameters by automatic model calibration improves the understanding of the two-phase flow processes and therefore increases the reliability of the subsequent simulation runs. (author) figs., tabs., refs

Automation of data processing and calculation of retention parameters and thermodynamic data for gas chromatography

Science.gov (United States)

Makarycheva, A. I.; Faerman, V. A.

2017-02-01

The analyses of automation patterns is performed and the programming solution for the automation of data processing of the chromatographic data and their further information storage with a help of a software package, Mathcad and MS Excel spreadsheets, is developed. The offered approach concedes the ability of data processing algorithm modification and does not require any programming experts participation. The approach provides making a measurement of the given time and retention volumes, specific retention volumes, a measurement of differential molar free adsorption energy, and a measurement of partial molar solution enthalpies and isosteric heats of adsorption. The developed solution is focused on the appliance in a small research group and is tested on the series of some new gas chromatography sorbents. More than 20 analytes were submitted to calculation of retention parameters and thermodynamic sorption quantities. The received data are provided in the form accessible to comparative analysis, and they are able to find sorbing agents with the most profitable properties to solve some concrete analytic issues.

Determination of parameters dissolution of yellow-cake. Production of uranyl nitrate - Gas precipitation of AUC

International Nuclear Information System (INIS)

Mellah, A.

1987-07-01

The different stages of the purification cycle of yellow-cakes have been studied thoroughly in order to obtain an ammonium uranyl carbonate (AUC) as an intermediate product of uranium dioxide (UO 2 ). The optimal parameters of yellow-cake dissolution, filtration, extraction by solvent, scrubbing and stripping were determined. An original program of thermodynamic calculation was developed for the determination of the free energies of yellow-cake dissolution reactions. Different numerical methods were used to determine the kinetic constant, the reaction order and correlation equations of uranyl nitrate density as a function of U and H + concentrations, before and after the extraction cycle. For the first time, Algerian filteraids were used for the filtration of uranyl nitrate solutions with satisfactory results. A laboratory designed installation enabled the precipitation of AUC by injection of ammonia and carbon dioxide gases. Interesting results have been obtained and further investigations should be carried out in order to optimize all the paremeters of the gas precipitation of AUC

Natural gas hydrates. Experimental techniques and their applications

Energy Technology Data Exchange (ETDEWEB)

Ye, Yuguang; Liu, Changling (eds.) [Qingdao Institute of Marine Geology (China). Gas Hydrate Laboratory

2013-07-01

Focuses on gas hydrate experiment in laboratory. Intends to provide practical significant parameters for gas hydrate exploration and exploitation in the oceanic and permafrost environments. Consists of different themes that present up-to-date information on hydrate experiments. ''Natural Gas Hydrates: Experimental Techniques and Their Applications'' attempts to broadly integrate the most recent knowledge in the fields of hydrate experimental techniques in the laboratory. The book examines various experimental techniques in order to provide useful parameters for gas hydrate exploration and exploitation. It provides experimental techniques for gas hydrates, including the detection techniques, the thermo-physical properties, permeability and mechanical properties, geochemical abnormalities, stability and dissociation kinetics, exploitation conditions, as well as modern measurement technologies etc.

Pressure oscillation delivery to the lung: Computer simulation of neonatal breathing parameters.

Science.gov (United States)

Al-Jumaily, Ahmed M; Reddy, Prasika I; Bold, Geoff T; Pillow, J Jane

2011-10-13

Preterm newborn infants may develop respiratory distress syndrome (RDS) due to functional and structural immaturity. A lack of surfactant promotes collapse of alveolar regions and airways such that newborns with RDS are subject to increased inspiratory effort and non-homogeneous ventilation. Pressure oscillation has been incorporated into one form of RDS treatment; however, how far it reaches various parts of the lung is still questionable. Since in-vivo measurement is very difficult if not impossible, mathematical modeling may be used as one way of assessment. Whereas many models of the respiratory system have been developed for adults, the neonatal lung remains essentially ill-described in mathematical models. A mathematical model is developed, which represents the first few generations of the tracheo-bronchial tree and the 5 lobes that make up the premature ovine lung. The elements of the model are derived using the lumped parameter approach and formulated in Simulink™ within the Matlab™ environment. The respiratory parameters at the airway opening compare well with those measured from experiments. The model demonstrates the ability to predict pressures, flows and volumes in the alveolar regions of a premature ovine lung. Copyright © 2011 Elsevier Ltd. All rights reserved.

Collective strong coupling with homogeneous Rabi frequencies using a 3D lumped element microwave resonator

International Nuclear Information System (INIS)

Angerer, Andreas; Astner, Thomas; Wirtitsch, Daniel; Majer, Johannes; Sumiya, Hitoshi; Onoda, Shinobu; Isoya, Junichi; Putz, Stefan

2016-01-01

We design and implement 3D-lumped element microwave cavities that spatially focus magnetic fields to a small mode volume. They allow coherent and uniform coupling to electron spins hosted by nitrogen vacancy centers in diamond. We achieve large homogeneous single spin coupling rates, with an enhancement of more than one order of magnitude compared to standard 3D cavities with a fundamental resonance at 3 GHz. Finite element simulations confirm that the magnetic field distribution is homogeneous throughout the entire sample volume, with a root mean square deviation of 1.54%. With a sample containing 10"1"7 nitrogen vacancy electron spins, we achieve a collective coupling strength of Ω = 12 MHz, a cooperativity factor C = 27, and clearly enter the strong coupling regime. This allows to interface a macroscopic spin ensemble with microwave circuits, and the homogeneous Rabi frequency paves the way to manipulate the full ensemble population in a coherent way.

New Pressure Gradient Equations for Lumped-Parameter Interior Ballistic Codes

Science.gov (United States)

1990-05-01

where k = p)M (L .18) and k2#, (L-19) P~V( td 6 and k12 0= C2 klP,,(.0 k gZbV(Zb) k,, P,, (L.2O) oil= .Ug - Up - V + L ( dt UP) 4.4 dlnp 2.U (s...mixture region, and (L.20) for u in the ullage region, we get 91K 1 -S E) pPBU2fbA d pAq U2 Z2Sb 2 (1-) pA - +,2 ," z2dz + -A V ~ + (z, _z) dtn p Td (L. 113...pp aupA -P at A = ihQ ) (R.9) or -uA ?~)-P A . (R.10) 5tz (I - C) p, Since the right side of (R.10) is a function of time only except for A, which is

Model-order reduction of lumped parameter systems via fractional calculus

Science.gov (United States)

Hollkamp, John P.; Sen, Mihir; Semperlotti, Fabio

2018-04-01

This study investigates the use of fractional order differential models to simulate the dynamic response of non-homogeneous discrete systems and to achieve efficient and accurate model order reduction. The traditional integer order approach to the simulation of non-homogeneous systems dictates the use of numerical solutions and often imposes stringent compromises between accuracy and computational performance. Fractional calculus provides an alternative approach where complex dynamical systems can be modeled with compact fractional equations that not only can still guarantee analytical solutions, but can also enable high levels of order reduction without compromising on accuracy. Different approaches are explored in order to transform the integer order model into a reduced order fractional model able to match the dynamic response of the initial system. Analytical and numerical results show that, under certain conditions, an exact match is possible and the resulting fractional differential models have both a complex and frequency-dependent order of the differential operator. The implications of this type of approach for both model order reduction and model synthesis are discussed.

Structure-soil-structure interaction of nuclear structures

International Nuclear Information System (INIS)

Snyder, M.D.; Shaw, D.E.; Hall, J.R. Jr.

1975-01-01

Structure-to-structure interaction resulting from coupling of the foundations through the soil has traditionally been neglected in the seismic analysis of nuclear power plants. This paper examines the phenomenon and available methods of analytical treatment, including finite element and lumped parameter methods. Finite element techniques have lead to the treatment of through soil coupling of structural foundations using two dimensional plane strain models owing to the difficulty of considering three dimensional finite element models. The coupling problem is treated by means of a lumped parameter model derived from elastic half-space considerations. Consequently, the method is applicable to the interaction of any number of foundations and allows the simultaneous application of tri-directional excitation. The method entails the idealization of interacting structures as lumped mass/shear beams with lumped soil springs and dampers beneath each foundation plus a coupling matrix between the interacting foundations. Utilizing classical elastic half-space methods, the individual foundation soil springs and dampers may be derived, accounting for the effects of embedment and soil layering, analogous to the methods used for single soil-structure, interaction problems. The coupling matrix is derived by generating influence coefficients based on the geometric relationship of the structures using classical half-space solutions. The influence coefficients form the coupling flexibility matrix which is inverted to yield the coupling matrix for the lumped parameter model

SCEPTIC, Pressure Drop, Flow Rate, Heat Transfer, Temperature in Reactor Heat Exchanger

International Nuclear Information System (INIS)

Kattchee, N.; Reynolds, W.C.

1975-01-01

1 - Nature of physical problem solved: SCEPTIC is a program for calculating pressure drop, flow rates, heat transfer rates, and temperature in heat exchangers such as fuel elements of typical gas or liquid cooled nuclear reactors. The effects of turbulent and heat interchange between flow passages are considered. 2 - Method of solution: The computation procedure amounts to a nodal of lumped parameter type of calculation. The axial mesh size is automatically selected to assure that a prescribed accuracy of results is obtained. 3 - Restrictions on the complexity of the problem: Maximum number of subchannels is 25, maximum number of heated surfaces is 46

Laser cutting of various materials: Kerf width size analysis and life cycle assessment of cutting process

Science.gov (United States)

Yilbas, Bekir Sami; Shaukat, Mian Mobeen; Ashraf, Farhan

2017-08-01

Laser cutting of various materials including Ti-6Al-4V alloy, steel 304, Inconel 625, and alumina is carried out to assess the kerf width size variation along the cut section. The life cycle assessment is carried out to determine the environmental impact of the laser cutting in terms of the material waste during the cutting process. The kerf width size is formulated and predicted using the lump parameter analysis and it is measured from the experiments. The influence of laser output power and laser cutting speed on the kerf width size variation is analyzed using the analytical tools including scanning electron and optical microscopes. In the experiments, high pressure nitrogen assisting gas is used to prevent oxidation reactions in the cutting section. It is found that the kerf width size predicted from the lump parameter analysis agrees well with the experimental data. The kerf width size variation increases with increasing laser output power. However, this behavior reverses with increasing laser cutting speed. The life cycle assessment reveals that material selection for laser cutting is critical for the environmental protection point of view. Inconel 625 contributes the most to the environmental damages; however, recycling of the waste of the laser cutting reduces this contribution.

Effects of gas chamber geometry and gas flow on the neutron production in a fast plasma focus neutron source

International Nuclear Information System (INIS)

Tarifeño-Saldivia, Ariel; Soto, Leopoldo

2014-01-01

This work reports that gas chamber geometry and gas flow management substantially affect the neutron production of a repetitive fast plasma focus. The gas flow rate is the most sensitive parameter. An appropriate design of the gas chamber combined with a suitable flow-rate management can lead to improvements in the neutron production of one order of magnitude working in a fast repetitive mode. (paper)

Comment on “Beyond the SCS-CN method: A theoretical framework for spatially lumped rainfall-runoff response” by M.S. Bartlett, A.J. Parolari, J.J. McDonnell and A. Porporato

Science.gov (United States)

Bartlett et al. [2016] performed a re-interpretation and modification of the space-time lumped USDA NRCS (formerly SCS) Curve Number (CN) method to extend its applicability to forested watersheds. We believe that the well documented limitations of the CN method severely constrains the applicability ...

Multi-objective genetic algorithm parameter estimation in a reduced nuclear reactor model

Energy Technology Data Exchange (ETDEWEB)

Marseguerra, M.; Zio, E.; Canetta, R. [Polytechnic of Milan, Dept. of Nuclear Engineering, Milano (Italy)

2005-07-01

The fast increase in computing power has rendered, and will continue to render, more and more feasible the incorporation of dynamics in the safety and reliability models of complex engineering systems. In particular, the Monte Carlo simulation framework offers a natural environment for estimating the reliability of systems with dynamic features. However, the time-integration of the dynamic processes may render the Monte Carlo simulation quite burdensome so that it becomes mandatory to resort to validated, simplified models of process evolution. Such models are typically based on lumped effective parameters whose values need to be suitably estimated so as to best fit to the available plant data. In this paper we propose a multi-objective genetic algorithm approach for the estimation of the effective parameters of a simplified model of nuclear reactor dynamics. The calibration of the effective parameters is achieved by best fitting the model responses of the quantities of interest to the actual evolution profiles. A case study is reported in which the real reactor is simulated by the QUAndry based Reactor Kinetics (Quark) code available from the Nuclear Energy Agency and the simplified model is based on the point kinetics approximation to describe the neutron balance in the core and on thermal equilibrium relations to describe the energy exchange between the different loops. (authors)

Multi-objective genetic algorithm parameter estimation in a reduced nuclear reactor model

International Nuclear Information System (INIS)

Marseguerra, M.; Zio, E.; Canetta, R.

2005-01-01

The fast increase in computing power has rendered, and will continue to render, more and more feasible the incorporation of dynamics in the safety and reliability models of complex engineering systems. In particular, the Monte Carlo simulation framework offers a natural environment for estimating the reliability of systems with dynamic features. However, the time-integration of the dynamic processes may render the Monte Carlo simulation quite burdensome so that it becomes mandatory to resort to validated, simplified models of process evolution. Such models are typically based on lumped effective parameters whose values need to be suitably estimated so as to best fit to the available plant data. In this paper we propose a multi-objective genetic algorithm approach for the estimation of the effective parameters of a simplified model of nuclear reactor dynamics. The calibration of the effective parameters is achieved by best fitting the model responses of the quantities of interest to the actual evolution profiles. A case study is reported in which the real reactor is simulated by the QUAndry based Reactor Kinetics (Quark) code available from the Nuclear Energy Agency and the simplified model is based on the point kinetics approximation to describe the neutron balance in the core and on thermal equilibrium relations to describe the energy exchange between the different loops. (authors)

The Effect of Process Parameters on the Synthesis of Ti and TiO2 Nanoparticles Producted by Electromagnetic Levitational Gas Condensation

Directory of Open Access Journals (Sweden)

Maryam Moazeni

2012-10-01

Full Text Available The nanoparticles of Ti and TiO2 have attracted extensive research interest because of their diverse applications in, for instance, catalysis, energy conversion, pigment and cosmetic manufacturing and biomedical engineering. Through this project, a one-step bulk synthesis method of electromagnetic levitational gas condensation (ELGC was utilized for the synthesis of monodispersed and crystalline Ti and TiO2 nanoparticles. Within the process, the Ti vapours ascending from the high temperature levitated droplet were condensed by an argon gas stream under atmospheric pressure. The TiO2 nanoparticles were produced by simultaneous injection of argon and oxygen into the reactor. The effects of flow rate of the condensing and oxidizing gases on the size and the size distribution of the nanoparticles were investigated. The particles were characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD and image analysis. The process parameters for the synthesis of the crystalline Ti and TiO2 nanoparticles were determined.

Catalytic hot gas cleaning of gasification gas

Energy Technology Data Exchange (ETDEWEB)

Simell, P. [VTT Energy, Espoo (Finland). Energy Production Technologies

1997-12-31

The aim of this work was to study the catalytic cleaning of gasification gas from tars and ammonia. In addition, factors influencing catalytic activity in industrial applications were studied, as well as the effects of different operation conditions and limits. Also the catalytic reactions of tar and ammonia with gasification gas components were studied. The activities of different catalyst materials were measured with laboratory-scale reactors fed by slip streams taken from updraft and fluid bed gasifiers. Carbonate rocks and nickel catalysts proved to be active tar decomposing catalysts. Ammonia decomposition was in turn facilitated by nickel catalysts and iron materials like iron sinter and iron dolomite. Temperatures over 850 deg C were required at 2000{sup -1} space velocity at ambient pressure to achieve almost complete conversions. During catalytic reactions H{sub 2} and CO were formed and H{sub 2}O was consumed in addition to decomposing hydrocarbons and ammonia. Equilibrium gas composition was almost achieved with nickel catalysts at 900 deg C. No deactivation by H{sub 2}S or carbon took place in these conditions. Catalyst blocking by particulates was avoided by using a monolith type of catalyst. The apparent first order kinetic parameters were determined for the most active materials. The activities of dolomite, nickel catalyst and reference materials were measured in different gas atmospheres using laboratory apparatus. This consisted of nitrogen carrier, toluene as tar model compound, ammonia and one of the components H{sub 2}, H{sub 2}O, CO, CO{sub 2}, CO{sub 2}+H{sub 2}O or CO+CO{sub 2}. Also synthetic gasification gas was used. With the dolomite and nickel catalyst the highest toluene decomposition rates were measured with CO{sub 2} and H{sub 2}O. In gasification gas, however, the rate was retarded due to inhibition by reaction products (CO, H{sub 2}, CO{sub 2}). Tar decomposition over dolomite was modelled by benzene reactions with CO{sub 2}, H

Determination of the main parameters of the cyclone separator of the flue gas produced during the smelting of secondary aluminum

Science.gov (United States)

Matusov, Jozef; Gavlas, Stanislav

2016-06-01

One way how is possible to separate the solid particulate pollutants from the flue gas is use the cyclone separators. The cyclone separators are very frequently used separators due to the simplicity of their design and their low operating costs. Separation of pollutants in the form of solids is carried out using three types of forces: inertia force, centrifugal force, gravity force. The main advantage is that cyclone consist of the parts which are resistant to wear and have long life time, e.g. various rotating and sliding parts. Mostly are used as pre-separators, because they have low efficiency in the separation of small particles. Their function is to separate larger particles from the flue gases which are subsequently cleaned in the other device which is capable of removing particles smaller than 1 µm, which is limiting size of particle separation. The article will deal with the issue of calculating the basic dimensions and main parameters of the cyclone separator from flue gas produced during the smelting of secondary aluminum.

Heat removal in gas-cooled fuel rod clusters

International Nuclear Information System (INIS)

Rehme, K.

1975-01-01

For a thermo- and fluid-dynamic analysis of fuel rod cluster subchannels for gas-cooled breeder reactors, the following values must be verified: a) friction coefficient as flow parameter; b) Stanton number as heat transfer parameter; c) influence of spacers on friction coefficient and Stanton number; d) heat and mass exchange between subchannels with different temperatures. These parameters are established by combining results of single experiments and of integral experiments. Mention is made of further studies to be performed in order to determine the heat removal from gas-cooled fast breeder fuel elements. (HR) [de

[Multicenter clinical study on umbilical cord arterial blood gas parameters for diagnosis of neonatal asphyxia].

Science.gov (United States)

2010-09-01

To obtain the normal range of statistics of umbilical artery blood gas parameters of the newborns for diagnosis of neonatal asphyxia. From March 2008 through September 2009, 17 978 singleton term appropriate for gestational age (AGA) or larger than gestational age (LGA) newborns in six hospitals of five provinces/autonomous regions were consecutively enrolled in this prospective study. The normal ranges of umbilical artery blood gas parameters were obtained from 17 645 newborns with 1 min Apgar score ≥ 8. The correlations between umbilical artery blood pH, BE and prenatal high-risk factors, Apgar scores, and organ damage were analyzed. The diagnostic criteria for asphyxia included the following: (1) Having high-risk factors that might cause asphyxia; (2) 1 min Apgar score ≤ 7 (the respiratory depression must be present); (3) At least one organ showed evidence of hypoxic damage; (4) Other causes of low Apgar score were excluded. The study focused on the distributive characteristics of umbilical artery blood pH (clinically corrected by Eisenberg formula) and BE values of the asphyxiated and non-asphyxiated cases in low Apgar score group, as well as the sensitivity and specificity of different selected pH and BE threshold spots within their distributing ranges. Among the 17 978 singleton term AGA or LGA newborns, the statistically normal range of umbilical artery blood pH, BE for the 17 645 cases with 1 min Apgar scores ≥ 8 were 7.20 ± 0.20 (x(-) ± 1.96 s) and -7.64 ± 10.02 (x(-) ± 1.96 s), respectively. The pH well correlated positively with BE (r = 0.734, P blood pH and BE values correlated positively with the Apgar scores. The umbilical artery blood pH and BE values correlated negatively with organ damage (r = 1, the P values = 0.000 for both). Among the 333 low Apgar score cases, the umbilical artery blood pH corrected values and BE values of the asphyxiated group (163 cases) were 7.011 ± 0.09 (x(-) ± s) and -14.98 ± 2.99 (x(-) ± s), being lower than

Correlation of Fukushima data with SSI models

International Nuclear Information System (INIS)

Miller, C.A.; Costantino, C.J.; Philippacopoulos, A.J.

1985-01-01

The seismic response of nuclear power plant structures is often calculated using lumped parameter methods. A finite element model of the structure is coupled to the soil with a spring-dashpot system used to represent the interaction process. The parameters of the interaction model are based on analytic solutions to simple problems which are idealizations of the actual problem. The objective of this work is to compare predicted response using the standard lumped parameter models with experimental data. These comparisons are shown to be good for fairly uniform soil systems. (orig.)

Simulation of Piezoelectric Transformers with COMSOL

DEFF Research Database (Denmark)

Andersen, Thomas; Andersen, Michael A. E.; Thomsen, Ole Cornelius

2012-01-01

In this work COMSOL is utilized to obtain the Mason lumped parameter model for a piezoelectric transformer (PT) design. The Mason lumped parameters are relevant in the design process of power converters. The magnitude of the impedance is simulated for a specific: interleaved multilayer thickness...... for simplifying the PT model are given in order to decrease the simulation time. This paper aims to aid electrical engineers with less knowledge within the field of mechanics, to be able to simulate a PT design with COMSOL and extract the key electrical parameters....

Experimental study of multi-component separation by gas centrifuge

International Nuclear Information System (INIS)

Zhou, M.S.; Liang, X.W.; Chen, W.N.; Yin, Y.T.

2006-01-01

Stable isotopes are applied in many areas and most stable isotopes are multi-component, This paper presents experimental results of several stable isotopes separation conducted in Tsinghua University by using ultra-speed gas centrifuges. Xe, WF 6 , TeF 6 , SiHCl 3 , SiF 4 were chosen as the process gases. By adjusting some of the centrifuge's parameters, the suitable centrifuge parameters for different process gas separations were found and the overall unit separation factors γ 0 were obtained by means of single gas centrifuge separation. The experimental results show that with appropriate process gases, stable isotope separation by gas centrifuge was effective. (authors)

Analytical model for transient fluid mixing in upper outlet plenum of an LMFBR

International Nuclear Information System (INIS)

Yang, J.W.; Agrawal, A.K.

1976-01-01

A two-zone mixing model based on the lumped-parameter approach was developed for the analysis of transient thermal response in the outlet plenum of an LMFBR. The maximum penetration of core flow is used as the criterion for dividing the sodium region into two mixing zones. The model considers the transient sodium temperature affected by the thermal expansion of sodium, heat transfer with cover gas, heat capacity of different sections of metal and the addition of by-pass flow into the plenum. The results of numerical calculations indicate that effects of flow stratification, chimney height, metal heat capacity and by-pass flow are important for transient sodium temperature calculation. Thermal expansion of sodium and heat transfer with the cover gas do not play any significant role on sodium temperature

Correlation between arterial and venous blood gas analysis parameters in patients with acute exacerbation of chronic obstructive pulmonary disease

Directory of Open Access Journals (Sweden)

Novović Miloš

2012-01-01

Full Text Available Introduction. Arterial blood gas (ABG analyses have an important role in the assessment and monitoring of the metabolic and oxygen status of patients with acute exacerbation of chronic obstructive pulmonary disease (COPD. Arterial puncture could have a lot of adverse effects, while sampling of venous blood is simpler and is not so invasive. Objective. The aim of this study was to evaluate whether venous blood gas (VBG values of pH, partial pressure of carbon dioxide (PCO2, partial oxygen pressure (PO2, bicarbonate (HCO3, and venous and arterial blood oxygen saturation (SO2 can reliably predict ABG levels in patients with acute exacerbation of COPD. Methods. Forty-seven patients with a prior diagnosis of COPD were included in this prospective study. The patients with acute exacerbation of this disease were examined at the General Hospital EMS Department in Prijepolje. ABG samples were taken immediately after venous sampling, and both were analyzed. Results. The Pearson correlation coefficients between arterial and venous parameters were 0.828, 0.877, 0.599, 0.896 and 0.312 for pH, PCO2, PO2, HCO3 and SO2, respectively. The statistically significant correlation between arterial and venous pH, PCO2 and HCO3, values was found in patients with acute exacerbation of COPD (p<0.001. Conclusion. When we cannot provide arterial blood for analysis, venous values of the pH, Pv,CO2 and HCO3 parameters can be an alternative to their arterial equivalents in the interpretation of the metabolic status in patients with acute exacerbation of COPD, while the values of venous Pv,O2 and Sv,O2 cannot be used as predictors in the assessment of oxygen status of such patients.

Generation and mid-IR measurement of a gas-phase to predict security parameters of aviation jet fuel.

Science.gov (United States)

Gómez-Carracedo, M P; Andrade, J M; Calviño, M A; Prada, D; Fernández, E; Muniategui, S

2003-07-27

The worldwide use of kerosene as aviation jet fuel makes its safety considerations of most importance not only for aircraft security but for the workers' health (chronic and/or acute exposure). As most kerosene risks come from its vapours, this work focuses on predicting seven characteristics (flash point, freezing point, % of aromatics and four distillation points) which assess its potential hazards. Two experimental devices were implemented in order to, first, generate a kerosene vapour phase and, then, to measure its mid-IR spectrum. All the working conditions required to generate the gas phase were optimised either in a univariate or a multivariate (SIMPLEX) approach. Next, multivariate prediction models were deployed using partial least squares regression and it was found that both the average prediction errors and precision parameters were satisfactory, almost always well below the reference figures.

Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with neon

Science.gov (United States)

Malinina, A. A.; Malinin, A. N.

2013-12-01

Results are presented from studies of the optical characteristics and parameters of plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with neon—the working medium of a non-coaxial exciplex gas-discharge emitter. The electron energy distribution function, the transport characteristics, the specific power losses for electron processes, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering by the working mixture components are determined as functions of the reduced electric field. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules is found to be 1.6 × 10-14 m3/s for a reduced electric field of E/ N = 15 Td, at which the maximum emission intensity in the blue-green spectral region (λmax = 502 nm) was observed in this experiment.

Thermodynamics of two-parameter quantum group Bose and Fermi gases

International Nuclear Information System (INIS)

Algin, A.

2005-01-01

The high and low temperature thermodynamic properties of the two-parameter deformed quantum group Bose and Fermi gases with SU p/q (2) symmetry are studied. Starting with a SU p/q (2)-invariant bosonic as well as fermionic Hamiltonian, several thermodynamic functions of the system such as the average number of particles, internal energy and equation of state are derived. The effects of two real independent deformation parameters p and q on the properties of the systems are discussed. Particular emphasis is given to a discussion of the Bose-Einstein condensation phenomenon for the two-parameter deformed quantum group Bose gas. The results are also compared with earlier undeformed and one-parameter deformed versions of Bose and Fermi gas models. (author)

Integrated PC-based system for detecting and parameter monitoring at the Dubna Gas Filled Recoil Separator

International Nuclear Information System (INIS)

Tsyganov, Yu.S.; Polyakov, A.N.; Sukhov, A.M.

2012-01-01

New detection system of the Dubna Gas Filled Recoil Separator (DGFRS) was put into operation in May 2012. It includes 32-strip position sensitive PIPS detector manufactured by CANBERRA NV, 24-strip back side PIPS detector, 8-strip V ETO P IPS detector, time-of-flight low pressure (∼1.7 Torr) pentane-filled gaseous detector, CAMAC fast ADC's with 5 μs dead time per three signals (energy, top position, bottom position), modified CC012 crate controller and PC-based C ++ Builder code for spectrometry data acquisition. New parameter monitoring system (project) is reported too together with the brief review of the present system. It is planned to put into operation with this system during 2013-2014. Examples of applications in the long-term experiments aimed at the synthesis of superheavy elements in 48 Ca induced complete fusion nuclear reactions are also presented. Namely with the DGFRS facility 45 new isotopes of superheavy nuclei were synthesized since 2001

Inverse modeling for the determination of hydrogeological parameters of a two-phase system

International Nuclear Information System (INIS)

Finsterle, S.

1993-01-01

Investigations related to the disposal of radioactive wastes in Switzerland are dealing with formations containing natural gas as potential host rock for a repository. Moreover, gas generation in the repository itself may lead to an unsaturated zone of significant extent and impact on the system's performance. The site characterization procedure requires the estimation of hydraulic properties being used as input parameters for a two-phase two-component numerical simulator. In this study, estimates of gas related formation parameters are obtained by inverse modeling. Based on discrete observations of the system's state, model parameters can be estimated within the framework of a given conceptual model by means of optimization techniques. This study presents the theoretical background that relates field data to the model parameters. A parameter estimation procedure is proposed and implemented in a computer code for automatic model calibration. This tool allows to identify key parameters affecting flow of water and gas in porous media. The inverse modeling approach is verified using data from a synthetic laboratory experiment. In addition, the Gastest performed at the Grimsel Test Site is analyzed in order to demonstrate the applicability of the proposed procedure when used with data from a real geologic environment. Estimation of hydrogeologic parameters by automatic model calibration improves the understanding of the two-phase flow processes and therefore increases the reliability of the subsequent simulation runs. (author) figs., tabs., 100 refs

The Hildebrand solubility parameters of ionic liquids-part 2.

Science.gov (United States)

Marciniak, Andrzej

2011-01-01

The Hildebrand solubility parameters have been calculated for eight ionic liquids. Retention data from the inverse gas chromatography measurements of the activity coefficients at infinite dilution were used for the calculation. From the solubility parameters, the enthalpies of vaporization of ionic liquids were estimated. Results are compared with solubility parameters estimated by different methods.

Gas breakdown in tokamaks

International Nuclear Information System (INIS)

Abramov, V.A.; Pogutse, O.P.; Yurchenko, Eh.I.

1975-01-01

The initial stage of the charge development in a tokomak is considered theoretically. It is supposed that all electrons produced in neutral gas ionisation process are in the regime of an almost continuous acceleration. The production time of a given electron density is calculated as a function of the neutral gas density and of parameters of the vortex electric field. The mechanism of plasma escape on walls is considered. It is shown that the escaping time is defined by a specific inertial flow of plasma and depends on whether chamber walls are metal or dielectric. The criterion of the gas breakdown in a toroidal system is formulated. The developed theory is shown to explain a strong dependence of the breakdown on the gas initial density [ru

Activation method for measurement of neutron spectrum parameters

International Nuclear Information System (INIS)

Efimov, B.V.; Demidov, A.M.; Ionov, V.S.; Konjaev, S.I.; Marin, S.V.; Bryzgalov, V.I.

2007-01-01

Experimental researches of spectrum parameters of neutrons at nuclear installations RRC KI are submitted. The installations have different designs of the cores, reflector, parameters and types of fuel elements. Measurements were carried out with use of the technique developed in RRC KI for irradiation resonance detectors UKD. The arrangement of detectors in the cores ensured possibility of measurement of neutron spectra with distinguished values of parameters. The spectrum parameters which are introduced by parametrical representation of a neutrons spectrum in the form corresponding to formalism Westcott. On experimental data were determinate absolute values of density neutron flux (DNF) in thermal and epithermal area of a spectrum (F t , f epi ), empirical dependence of temperature of neutron gas (Tn) on parameter of a rigidity of a spectrum (z), density neutron flux in transitional energy area of the spectrum. Dependences of spectral indexes of nuclides (UDy/UX), included in UKD, from a rigidity z and-or temperatures of neutron gas Tn are obtained.B Tools of mathematical processing of results are used for activation data and estimation of parameters of a spectrum (F t , f epi , z, Tn, UDy/UX). In the paper are presented some results of researches of neutron spectrum parameters of the nuclear installations (Authors)

Compact triple band-stop filter using novel epsilon-shaped metamaterial with lumped capacitor

Science.gov (United States)

Ali, W. A. E.; Hamdalla, M. Z. M.

2018-04-01

This paper presents the design of a novel epsilon-shaped metamaterial unit cell structure that is applicable for single-band and multi-band applications. A closed-form formulas to control the resonance frequencies of the proposed design are included. The proposed unit cell, which exhibits negative permeability at its frequency bands, is etched from the ground plane to form a band-stop filter. The filter design is constructed to validate the band-notched characteristics of the proposed unit cell. A lumped capacitor is inserted for size reduction purpose in addition to multi-resonance generation. The fundamental resonance frequency is translated from 3.62 GHz to 2.45 GHz, which means that the filter size will be more compact (more than 32% size reduction). The overall size of the proposed filter is 13 × 6 × 1.524 mm3, where the electrical size is 0.221λg × 0.102λg × 0.026λg at the lower frequency band (2.45 GHz). Two other resonance frequencies are generated at 5.3 GHz and 9.2 GHz, which confirm the multi-band behavior of the proposed filter. Good agreement between simulated and measured characteristics of the fabricated filter prototype is achieved.

Formation of hot intergalactic gas by gas ejection from a galaxy in an early explosive era

International Nuclear Information System (INIS)

Ikeuchi, Satoru

1977-01-01

Chemical evolution of a galaxy in an early explosive era is studied by means of one zone model. Calculating the thermal properties of interstellar gas and the overlapping factor of expanding supernova-remnant shells, the gas escape conditions from a galaxy are examined. From these, it is shown that the total mass of ejected gas from a galaxy amounts to 10 -- 40% of the initial mass of a galaxy. The ejected gas extends to the intergalactic space and the whole universe. The mass, the heavy-element abundance and other physical properties of thus formed intergalactic gas are investigated for various parameters of galactic evolution. Some other effects of gas release on the evolution of a galaxy and the evolution of the universe are discussed. (auth.)

Combined Yamamoto approach for simultaneous estimation of adsorption isotherm and kinetic parameters in ion-exchange chromatography.

Science.gov (United States)

Rüdt, Matthias; Gillet, Florian; Heege, Stefanie; Hitzler, Julian; Kalbfuss, Bernd; Guélat, Bertrand

2015-09-25

Application of model-based design is appealing to support the development of protein chromatography in the biopharmaceutical industry. However, the required efforts for parameter estimation are frequently perceived as time-consuming and expensive. In order to speed-up this work, a new parameter estimation approach for modelling ion-exchange chromatography in linear conditions was developed. It aims at reducing the time and protein demand for the model calibration. The method combines the estimation of kinetic and thermodynamic parameters based on the simultaneous variation of the gradient slope and the residence time in a set of five linear gradient elutions. The parameters are estimated from a Yamamoto plot and a gradient-adjusted Van Deemter plot. The combined approach increases the information extracted per experiment compared to the individual methods. As a proof of concept, the combined approach was successfully applied for a monoclonal antibody on a cation-exchanger and for a Fc-fusion protein on an anion-exchange resin. The individual parameter estimations for the mAb confirmed that the new approach maintained the accuracy of the usual Yamamoto and Van Deemter plots. In the second case, offline size-exclusion chromatography was performed in order to estimate the thermodynamic parameters of an impurity (high molecular weight species) simultaneously with the main product. Finally, the parameters obtained from the combined approach were used in a lumped kinetic model to simulate the chromatography runs. The simulated chromatograms obtained for a wide range of gradient lengths and residence times showed only small deviations compared to the experimental data. Copyright © 2015 Elsevier B.V. All rights reserved.

Time-varying parameter models for catchments with land use change: the importance of model structure

Science.gov (United States)

Pathiraja, Sahani; Anghileri, Daniela; Burlando, Paolo; Sharma, Ashish; Marshall, Lucy; Moradkhani, Hamid

2018-05-01

Rapid population and economic growth in Southeast Asia has been accompanied by extensive land use change with consequent impacts on catchment hydrology. Modeling methodologies capable of handling changing land use conditions are therefore becoming ever more important and are receiving increasing attention from hydrologists. A recently developed data-assimilation-based framework that allows model parameters to vary through time in response to signals of change in observations is considered for a medium-sized catchment (2880 km2) in northern Vietnam experiencing substantial but gradual land cover change. We investigate the efficacy of the method as well as the importance of the chosen model structure in ensuring the success of a time-varying parameter method. The method was used with two lumped daily conceptual models (HBV and HyMOD) that gave good-quality streamflow predictions during pre-change conditions. Although both time-varying parameter models gave improved streamflow predictions under changed conditions compared to the time-invariant parameter model, persistent biases for low flows were apparent in the HyMOD case. It was found that HyMOD was not suited to representing the modified baseflow conditions, resulting in extreme and unrealistic time-varying parameter estimates. This work shows that the chosen model can be critical for ensuring the time-varying parameter framework successfully models streamflow under changing land cover conditions. It can also be used to determine whether land cover changes (and not just meteorological factors) contribute to the observed hydrologic changes in retrospective studies where the lack of a paired control catchment precludes such an assessment.

Time-varying parameter models for catchments with land use change: the importance of model structure

Directory of Open Access Journals (Sweden)

S. Pathiraja

2018-05-01

Full Text Available Rapid population and economic growth in Southeast Asia has been accompanied by extensive land use change with consequent impacts on catchment hydrology. Modeling methodologies capable of handling changing land use conditions are therefore becoming ever more important and are receiving increasing attention from hydrologists. A recently developed data-assimilation-based framework that allows model parameters to vary through time in response to signals of change in observations is considered for a medium-sized catchment (2880 km2 in northern Vietnam experiencing substantial but gradual land cover change. We investigate the efficacy of the method as well as the importance of the chosen model structure in ensuring the success of a time-varying parameter method. The method was used with two lumped daily conceptual models (HBV and HyMOD that gave good-quality streamflow predictions during pre-change conditions. Although both time-varying parameter models gave improved streamflow predictions under changed conditions compared to the time-invariant parameter model, persistent biases for low flows were apparent in the HyMOD case. It was found that HyMOD was not suited to representing the modified baseflow conditions, resulting in extreme and unrealistic time-varying parameter estimates. This work shows that the chosen model can be critical for ensuring the time-varying parameter framework successfully models streamflow under changing land cover conditions. It can also be used to determine whether land cover changes (and not just meteorological factors contribute to the observed hydrologic changes in retrospective studies where the lack of a paired control catchment precludes such an assessment.

Determination of reference intervals and comparison of venous blood gas parameters using standard and non-standard collection methods in 24 cats.

Science.gov (United States)

Bachmann, Karin; Kutter, Annette Pn; Schefer, Rahel Jud; Marly-Voquer, Charlotte; Sigrist, Nadja

2017-08-01

Objectives The aim of this study was to determine in-house reference intervals (RIs) for venous blood analysis with the RAPIDPoint 500 blood gas analyser using blood gas syringes (BGSs) and to determine whether immediate analysis of venous blood collected into lithium heparin (LH) tubes can replace anaerobic blood sampling into BGSs. Methods Venous blood was collected from 24 healthy cats and directly transferred into a BGS and an LH tube. The BGS was immediately analysed on the RAPIDPoint 500 followed by the LH tube. The BGSs and LH tubes were compared using paired t-test or Wilcoxon matched-pairs signed-rank test, Bland-Altman and Passing-Bablok analysis. To assess clinical relevance, bias or percentage bias between BGSs and LH tubes was compared with the allowable total error (TEa) recommended for the respective parameter. Results Based on the values obtained from the BGSs, RIs were calculated for the evaluated parameters, including blood gases, electrolytes, glucose and lactate. Values derived from LH tubes showed no significant difference for standard bicarbonate, whole blood base excess, haematocrit, total haemoglobin, sodium, potassium, chloride, glucose and lactate, while pH, partial pressure of carbon dioxide and oxygen, actual bicarbonate, extracellular base excess, ionised calcium and anion gap were significantly different to the samples collected in BGSs ( P glucose and lactate can be made based on blood collected in LH tubes and analysed within 5 mins. For pH, partial pressure of carbon dioxide and oxygen, extracellular base excess, anion gap and ionised calcium the clinically relevant alterations have to be considered if analysed in LH tubes.

The Hildebrand Solubility Parameters of Ionic Liquids—Part 2

Science.gov (United States)

Marciniak, Andrzej

2011-01-01

The Hildebrand solubility parameters have been calculated for eight ionic liquids. Retention data from the inverse gas chromatography measurements of the activity coefficients at infinite dilution were used for the calculation. From the solubility parameters, the enthalpies of vaporization of ionic liquids were estimated. Results are compared with solubility parameters estimated by different methods. PMID:21747694

The Hildebrand Solubility Parameters of Ionic Liquids—Part 2

Directory of Open Access Journals (Sweden)

Andrzej Marciniak

2011-06-01

Full Text Available The Hildebrand solubility parameters have been calculated for eight ionic liquids. Retention data from the inverse gas chromatography measurements of the activity coefficients at infinite dilution were used for the calculation. From the solubility parameters, the enthalpies of vaporization of ionic liquids were estimated. Results are compared with solubility parameters estimated by different methods.

Laboratory Photoionization Fronts in Nitrogen Gas: A Numerical Feasibility and Parameter Study