Optical Model and Cross Section Uncertainties
Energy Technology Data Exchange (ETDEWEB)
Herman,M.W.; Pigni, M.T.; Dietrich, F.S.; Oblozinsky, P.
2009-10-05
Distinct minima and maxima in the neutron total cross section uncertainties were observed in model calculations using spherical optical potential. We found this oscillating structure to be a general feature of quantum mechanical wave scattering. Specifically, we analyzed neutron interaction with 56Fe from 1 keV up to 65 MeV, and investigated physical origin of the minima.We discuss their potential importance for practical applications as well as the implications for the uncertainties in total and absorption cross sections.
Active-beam cross-sectional modeling
Cesnik, Carlos E. S.; Ortega-Morales, Miguel
2000-06-01
A finite-element based analysis for modeling active composite beams with embedded anisotropic actuation is presented. It is derived from three-dimensional electroelasticity, where the original problem is reduced via the variational asymptotic method. The resulting cross-sectional analysis takes into consideration passive and active anisotropic and nonhomogeneous materials, and represents general (thin-walled, thick-walled, solid) cross-sectional geometries. The formulation requires neither the costly use of 3-D finite element discretization nor the loss of accuracy inherent to any simplified representation of the cross section. The developed formulation is numerically implemented in VABS-A, and several numerical and experimental tests cases are used to support validation of the proposed theory. Also, the effect of the presence of a core in originally hallow configurations is presented and counter-intuitive conclusions are discussed. The generality of the method and accuracy of the results increase confidence at the design stage that the active beam structure will perform as expected and, consequently, should lower costs from experimental tests and further adjustments.
Learning of Cross-Sectional Anatomy Using Clay Models
Oh, Chang-Seok; Kim, Ji-Young; Choe, Yeon Hyeon
2009-01-01
We incorporated clay modeling into gross anatomy and neuro-anatomy courses to help students understand cross-sectional anatomy. By making clay models, cutting them and comparing cut surfaces to CT and MR images, students learned how cross-sectional two-dimensional images were created from three-dimensional structure of human organs. Most students…
Modeling and analysis of ground target radiation cross section
Institute of Scientific and Technical Information of China (English)
SHI Xiang; LOU GuoWei; LI XingGuo
2008-01-01
Based on the analysis of the passive millimeter wave (MMW) radiometer detection, the ground target radiation cross section is modeled as the new token for the target MMW radiant characteristics. Its ap-plication and actual testing are discussed and analyzed. The essence of passive MMW stealth is target radiation cross section reduction.
Models for Pooled Time-Series Cross-Section Data
Directory of Open Access Journals (Sweden)
Lawrence E Raffalovich
2015-07-01
Full Text Available Several models are available for the analysis of pooled time-series cross-section (TSCS data, defined as “repeated observations on fixed units” (Beck and Katz 1995. In this paper, we run the following models: (1 a completely pooled model, (2 fixed effects models, and (3 multi-level/hierarchical linear models. To illustrate these models, we use a Generalized Least Squares (GLS estimator with cross-section weights and panel-corrected standard errors (with EViews 8 on the cross-national homicide trends data of forty countries from 1950 to 2005, which we source from published research (Messner et al. 2011. We describe and discuss the similarities and differences between the models, and what information each can contribute to help answer substantive research questions. We conclude with a discussion of how the models we present may help to mitigate validity threats inherent in pooled time-series cross-section data analysis.
Electron induced inelastic and ionization cross section for plasma modeling
Verma, Pankaj; Mahato, Dibyendu; Kaur, Jaspreet; Antony, Bobby
2016-09-01
The present paper reports electron impact total inelastic and ionization cross section for silicon, germanium, and tin tetrahalides at energies varying from ionization threshold of the target to 5000 eV. These cross section data over a wide energy domain are very essential to understand the physico-chemical processes involved in various environments such as plasma modeling, semiconductor etching, atmospheric sciences, biological sciences, and radiation physics. However, the cross section data on the above mentioned molecules are scarce. In the present article, we report the computation of total inelastic cross section using spherical complex optical potential formalism and the estimation of ionization cross section through a semi-empirical method. The present ionization cross section result obtained for SiCl4 shows excellent agreement with previous measurements, while other molecules have not yet been investigated experimentally. Present results show more consistent behaviour than previous theoretical estimates. Besides cross sections, we have also studied the correlation of maximum ionization cross section with the square root of the ratio of polarizability to ionization potential for the molecules with known polarizabilities. A linear relation is observed between these quantities. This correlation is used to obtain approximate polarizability volumes for SiBr4, SiI4, GeCl4, GeBr4, and GeI4 molecules.
Photoproduction models for total cross section and shower development
Cornet, Fernando; Garcia Canal, Carlos; Grau, Agnes; Pancheri, Giulia; Sciutto, Sergio
2015-08-01
A model for the total photoproduction cross section, based on the ansatz that resummation of infrared gluons limits the rise induced by QCD minijets in all the total cross-sections, is used to simulate extended air showers initiated by cosmic rays with the AIRES simulation program. The impact on common shower observables, especially those related with muon production, is analysed and compared with the corresponding results obtained with previous photoproduction models.
Photoproduction models for total cross section and shower development
Cornet, Fernando; Grau, Agnes; Pancheri, Giulia; Sciutto, Sergio
2014-01-01
A model for the total photoproduction cross section based on the ansatz that resummation of infrared gluons limits the rise induced by QCD minijets in all the total cross-sections, is used to simulate extended air showers initiated by cosmic rays with the AIRES simulation program. The impact on common shower observables, especially those related with muon production, is analysed and compared with the corresponding results obtained with previous photoproduction models.
Photoproduction models for total cross section and shower development
Directory of Open Access Journals (Sweden)
Cornet Fernando
2015-01-01
Full Text Available A model for the total photoproduction cross section, based on the ansatz that resummation of infrared gluons limits the rise induced by QCD minijets in all the total cross-sections, is used to simulate extended air showers initiated by cosmic rays with the AIRES simulation program. The impact on common shower observables, especially those related with muon production, is analysed and compared with the corresponding results obtained with previous photoproduction models.
Modelling interaction cross sections for intermediate and low energy ions
Energy Technology Data Exchange (ETDEWEB)
Toburen, L.H.; Shinpaugh, J.L.; Justiniano, E.L.B
2002-07-01
When charged particles slow in tissue they undergo electron capture and loss processes than can have profound effects on subsequent interaction cross sections. Although a large amount of data exists for the interaction of bare charged particles with atoms and molecules, few experiments have been reported for these 'dressed' particles. Projectile electrons contribute to an impact-parameter-dependent screening of the projectile charge that precludes straightforward scaling of energy loss cross sections from those of bare charged particles. The objective of this work is to develop an analytical model for the energy-loss-dependent effects of screening on differential ionisation cross sections that can be used in track structure calculations for high LET ions. As a first step a model of differential ionisation cross sections for bare ions has been combined with a simple screening model to explore cross sections for intermediate and low energy dressed ions in collisions with atomic and molecular gas targets. The model is described briefly and preliminary results compared to measured electron energy spectra. (author)
Modelling interaction cross sections for intermediate and low energy ions.
Toburen, L H; Shinpaugh, J L; Justiniano, E L B
2002-01-01
When charged particles slow in tissue they undergo electron capture and loss processes that can have profound effects on subsequent interaction cross sections. Although a large amount of data exists for the interaction of bare charged particles with atoms and molecules, few experiments have been reported for these 'dressed' particles. Projectile electrons contribute to an impact-parameter-dependent screening of the projectile charge that precludes straightforward scaling of energy loss cross sections from those of bare charged particles. The objective of this work is to develop an analytical model for the energy-loss-dependent effects of screening on differential ionisation cross sections that can be used in track structure calculations for high LET ions. As a first step a model of differential ionisation cross sections for bare ions has been combined with a simple screening model to explore cross sections for intermediate and low energy dressed ions in collisions with atomic and molecular gas targets. The model is described briefly and preliminary results compared to measured ejected electron energy spectra.
Estimating Dynamic Models from Repeated Cross-Sections
Verbeek, M.J.C.M.; Vella, F.
2000-01-01
A major attraction of panel data is the ability to estimate dynamic models on an individual level. Moffitt (1993) and Collado (1998) have argued that such models can also be identified from repeated cross-section data. In this paper we reconsider this issue. We review the identification conditions u
Estimation of the Human Absorption Cross Section Via Reverberation Models
DEFF Research Database (Denmark)
Steinböck, Gerhard; Pedersen, Troels; Fleury, Bernard Henri;
2016-01-01
Since the presence of persons affects the reverberation time observed for in-room channels, the absorption cross section of a person can be estimated from measurements via Sabine's and Eyring's models for the reverberation time. We propose an estimator relying on the more accurate model by Eyring...... and compare the obtained results to those of Sabine's model. We find that the absorption by persons is large enough to be measured with a wideband channel sounder and that estimates of the human absorption cross section differ for the two models. The obtained values are comparable to values reported...... in the literature. We also suggest the use of controlled environments with low average absorption coefficients to obtain more reliable estimates. The obtained values can be used to predict the change of reverberation time with persons in the propagation environment. This allows prediction of channel characteristics...
Validation of elastic cross section models for space radiation applications
Werneth, C. M.; Xu, X.; Norman, R. B.; Ford, W. P.; Maung, K. M.
2017-02-01
The space radiation field is composed of energetic particles that pose both acute and long-term risks for astronauts in low earth orbit and beyond. In order to estimate radiation risk to crew members, the fluence of particles and biological response to the radiation must be known at tissue sites. Given that the spectral fluence at the boundary of the shielding material is characterized, radiation transport algorithms may be used to find the fluence of particles inside the shield and body, and the radio-biological response is estimated from experiments and models. The fidelity of the radiation spectrum inside the shield and body depends on radiation transport algorithms and the accuracy of the nuclear cross sections. In a recent study, self-consistent nuclear models based on multiple scattering theory that include the option to study relativistic kinematics were developed for the prediction of nuclear cross sections for space radiation applications. The aim of the current work is to use uncertainty quantification to ascertain the validity of the models as compared to a nuclear reaction database and to identify components of the models that can be improved in future efforts.
Requirements engineering for cross-sectional information chain models.
Hübner, U; Cruel, E; Gök, M; Garthaus, M; Zimansky, M; Remmers, H; Rienhoff, O
2012-01-01
Despite the wealth of literature on requirements engineering, little is known about engineering very generic, innovative and emerging requirements, such as those for cross-sectional information chains. The IKM health project aims at building information chain reference models for the care of patients with chronic wounds, cancer-related pain and back pain. Our question therefore was how to appropriately capture information and process requirements that are both generally applicable and practically useful. To this end, we started with recommendations from clinical guidelines and put them up for discussion in Delphi surveys and expert interviews. Despite the heterogeneity we encountered in all three methods, it was possible to obtain requirements suitable for building reference models. We evaluated three modelling languages and then chose to write the models in UML (class and activity diagrams). On the basis of the current project results, the pros and cons of our approach are discussed.
Modelling of reaction cross sections and prompt neutron emission
Hambsch, F.-J.; Tudora, A.; Oberstedt, S.
2010-10-01
Accurate nuclear data concerning reaction cross sections and the emission of prompt fission neutrons (i.e. multiplicity and spectra) as well as other fission fragment data are of great importance for reactor physics design, especially for the new Generation IV nuclear energy systems. During the past years for several actinides (238U(n, f) and 237Np(n, f)) both the reaction cross sections and prompt neutron multiplicities and spectra have been calculated within the frame of the EFNUDAT project.
Modelling of reaction cross sections and prompt neutron emission
Directory of Open Access Journals (Sweden)
Oberstedt S.
2010-10-01
Full Text Available Accurate nuclear data concerning reaction cross sections and the emission of prompt fission neutrons (i.e. multiplicity and spectra as well as other fission fragment data are of great importance for reactor physics design, especially for the new Generation IV nuclear energy systems. During the past years for several actinides (238U(n, f and 237Np(n, f both the reaction cross sections and prompt neutron multiplicities and spectra have been calculated within the frame of the EFNUDAT project.
Minnesota Department of Natural Resources — FEMA Cross Sections are required for any Digital Flood Insurance Rate Map database where cross sections are shown on the Flood Insurance Rate Map (FIRM). Normally...
GIS-based data model and tools for creating and managing two-dimensional cross sections
Whiteaker, Timothy L.; Jones, Norm; Strassberg, Gil; Lemon, Alan; Gallup, Doug
2012-02-01
While modern Geographic Information Systems (GIS) software is robust in handling maps and data in plan view, the software generally falls short when representing features in section view. Further complicating the issue is the fact that geologic cross sections are often drawn by connecting a series of wells together that do not fall along a single straight line. In this case, the x-axis of the cross section represents the distance along the set of individual lines connecting the series of wells, effectively "flattening out" the cross section along this path to create a view of the subsurface with which geologists often work in printed folios. Even 3D-enabled GIS cannot handle this type of cross section. A GIS data model and tools for creating and working with two-dimensional cross sections are presented. The data model and tools create a framework that can be applied using ESRI's ArcGIS software, enabling users to create, edit, manage, and print two-dimensional cross sections from within one of the most well-known GIS software packages. The data model is a component of the arc hydro groundwater data model, which means all two-dimensional cross sections are inherently linked to other features in the hydrogeologic domain, including those represented by xyz coordinates in real world space. Thus, the creation of two-dimensional cross sections can be guided by or completely driven from standard GIS data, and geologic interpretations established on two-dimensional cross sections can be translated back to real world coordinates to create three-dimensional features such as fence diagrams, giving GIS users the capacity to characterize the subsurface environment in a variety of integrated views that was not possible before. A case study for the Sacramento Regional Model in California demonstrates the application of the methodology in support of a regional groundwater management plan.
On two-parameter models of photon cross sections: application to dual-energy CT imaging.
Williamson, Jeffrey F; Li, Sicong; Devic, Slobodan; Whiting, Bruce R; Lerma, Fritz A
2006-11-01
The goal of this study is to evaluate the theoretically achievable accuracy in estimating photon cross sections at low energies (20-1000 keV) from idealized dual-energy x-ray computed tomography (CT) images. Cross-section estimation from dual-energy measurements requires a model that can accurately represent photon cross sections of any biological material as a function of energy by specifying only two characteristic parameters of the underlying material, e.g., effective atomic number and density. This paper evaluates the accuracy of two commonly used two-parameter cross-section models for postprocessing idealized measurements derived from dual-energy CT images. The parametric fit model (PFM) accounts for electron-binding effects and photoelectric absorption by power functions in atomic number and energy and scattering by the Klein-Nishina cross section. The basis-vector model (BVM) assumes that attenuation coefficients of any biological substance can be approximated by a linear combination of mass attenuation coefficients of two dissimilar basis substances. Both PFM and BVM were fit to a modern cross-section library for a range of elements and mixtures representative of naturally occurring biological materials (Z = 2-20). The PFM model, in conjunction with the effective atomic number approximation, yields estimated the total linear cross-section estimates with mean absolute and maximum error ranges of 0.6%-2.2% and 1%-6%, respectively. The corresponding error ranges for BVM estimates were 0.02%-0.15% and 0.1%-0.5%. However, for photoelectric absorption frequency, the PFM absolute mean and maximum errors were 10.8%-22.4% and 29%-50%, compared with corresponding BVM errors of 0.4%-11.3% and 0.5%-17.0%, respectively. Both models were found to exhibit similar sensitivities to image-intensity measurement uncertainties. Of the two models, BVM is the most promising approach for realizing dual-energy CT cross-section measurement.
Modelling of N21P emission rates in aurora using various cross sections for excitation
Directory of Open Access Journals (Sweden)
O. Jokiaho
2009-06-01
Full Text Available Measurements of N21P auroral emissions from the (4,1 and (5,2 bands have been made at high temporal and spatial resolution in the region of the magnetic zenith. The instrument used was the auroral imager ASK, situated at Ramfjordmoen, Norway (69.6 N, 19.2 E on 22 October 2006. Measurements from the European Incoherent Scatter Radar (EISCAT have been combined with the optical measurements, and incorporated into an ionospheric model to obtain height profiles of electron density and emission rates of the N21P bands. The radar data provide essential verification that the energy flux used in the model is correct. One of the most important inputs to the model is the cross section for excitation to the B3Πg electronic state, as well as the cross sections to higher states from which cascading into the B state occurs. The balance equations for production and loss of the populations of all levels in each state are solved in order to find the cascade contributions. Several sets of cross sections have been considered, and selected cross sections have been used to construct "emission" cross sections for the observed bands. The resulting brightnesses are compared with those measured by ASK. The importance of specific contributions from cascading is found, with more than 50% of the total brightness resulting from cascading. The cross sections used are found to produce a range of brightnesses well within the uncertainty of both the modelled and measured values.
Modeling plasma-based CO2 conversion: crucial role of the dissociation cross section
Bogaerts, Annemie; Wang, Weizong; Berthelot, Antonin; Guerra, Vasco
2016-10-01
Plasma-based CO2 conversion is gaining increasing interest worldwide. A large research effort is devoted to improving the energy efficiency. For this purpose, it is very important to understand the underlying mechanisms of the CO2 conversion. The latter can be obtained by computer modeling, describing in detail the behavior of the various plasma species and all relevant chemical processes. However, the accuracy of the modeling results critically depends on the accuracy of the assumed input data, like cross sections. This is especially true for the cross section of electron impact dissociation, as the latter process is believed to proceed through electron impact excitation, but it is not clear from the literature which excitation channels effectively lead to dissociation. Therefore, the present paper discusses the effect of different electron impact dissociation cross sections reported in the literature on the calculated CO2 conversion, for a dielectric barrier discharge (DBD) and a microwave (MW) plasma. Comparison is made to experimental data for the DBD case, to elucidate which cross section might be the most realistic. This comparison reveals that the cross sections proposed by Itikawa and by Polak and Slovetsky both seem to underestimate the CO2 conversion. The cross sections recommended by Phelps with thresholds of 7 eV and 10.5 eV yield a CO2 conversion only slightly lower than the experimental data, but the sum of both cross sections overestimates the values, indicating that these cross sections represent dissociation, but most probably also include other (pure excitation) channels. Our calculations indicate that the choice of the electron impact dissociation cross section is crucial for the DBD, where this process is the dominant mechanism for CO2 conversion. In the MW plasma, it is only significant at pressures up to 100 mbar, while it is of minor importance for higher pressures, when dissociation proceeds mainly through collisions of CO2 with heavy
Towards a construction of inclusive collision cross-sections in the massless Nelson model
2011-01-01
The conventional approach to the infrared problem in perturbative quantum electrodynamics relies on the concept of inclusive collision cross-sections. A non-perturbative variant of this notion was introduced in algebraic quantum field theory. Relying on these insights, we take first steps towards a non-perturbative construction of inclusive collision cross-sections in the massless Nelson model. We show that our proposal is consistent with the standard scattering theory in the absence of the i...
Total hadronic cross section and the elastic slope: An almost model-independent connection
Energy Technology Data Exchange (ETDEWEB)
Fagundes, D.A., E-mail: fagundes@ifi.unicamp.br [Universidade Estadual de Campinas - UNICAMP, Instituto de Fisica Gleb Wataghin, 13083-859 Campinas, SP (Brazil); Menon, M.J., E-mail: menon@ifi.unicamp.br [Universidade Estadual de Campinas - UNICAMP, Instituto de Fisica Gleb Wataghin, 13083-859 Campinas, SP (Brazil)
2012-04-15
An almost model-independent parametrization for the ratio of the total cross section to the elastic slope, as function of the center of mass energy, is introduced. The analytical result is based on the approximate relation of this quantity with the ratio R of the elastic to total cross section and empirical fits to the R data from proton-proton scattering above 10 GeV, under the conditions of asymptotic unitarity and the black-disk limit. This parametrization may be useful in studies of extensive air showers and the determination of the proton-proton total cross section from proton-air production cross section in cosmic-ray experiments.
Ridolfi, E.; Alfonso, L.; Di Baldassarre, G.; Napolitano, F.
2016-06-01
The description of river topography has a crucial role in accurate one-dimensional (1D) hydraulic modelling. Specifically, cross-sectional data define the riverbed elevation, the flood-prone area, and thus, the hydraulic behavior of the river. Here, the problem of the optimal cross-sectional spacing is solved through an information theory-based concept. The optimal subset of locations is the one with the maximum information content and the minimum amount of redundancy. The original contribution is the introduction of a methodology to sample river cross sections in the presence of bridges. The approach is tested on the Grosseto River (IT) and is compared to existing guidelines. The results show that the information theory-based approach can support traditional methods to estimate rivers' cross-sectional spacing.
Extension of non-linear beam models with deformable cross sections
Sokolov, I.; Krylov, S.; Harari, I.
2015-12-01
Geometrically exact beam theory is extended to allow distortion of the cross section. We present an appropriate set of cross-section basis functions and provide physical insight to the cross-sectional distortion from linear elastostatics. The beam formulation in terms of material (back-rotated) beam internal force resultants and work-conjugate kinematic quantities emerges naturally from the material description of virtual work of constrained finite elasticity. The inclusion of cross-sectional deformation allows straightforward application of three-dimensional constitutive laws in the beam formulation. Beam counterparts of applied loads are expressed in terms of the original three-dimensional data. Special attention is paid to the treatment of the applied stress, keeping in mind applications such as hydrogel actuators under environmental stimuli or devices made of electroactive polymers. Numerical comparisons show the ability of the beam model to reproduce finite elasticity results with good efficiency.
A quasi-analytical model for nanowire FETs with arbitrary polygonal cross section
De Michielis, L.; Selmi, L.; Ionescu, A. M.
2010-09-01
In this work a quasi-analytical physical model has been developed for the prediction of the potential in SiNW devices with arbitrary polygonal cross section. The model is then extended to the transport direction; a method for the calculation of the natural channel length has been proposed and validated by means of 2D and 3D numerical device simulations. With the results based on the proposed model it is possible to compare nanowires with cross sections of different shape and predict the minimum technological gate length able to assure immunity to the SCEs.
Assessment of some optical model potentials in predicting neutron cross sections
Energy Technology Data Exchange (ETDEWEB)
Kumar, A.; Young, P.G.; Chadwick, M.B.
1998-03-01
Optical model potential parameters play an important role in the evaluation of nuclear data for applied purposes. The IAEA Coordinated Research Program on {open_quotes}Reference Input Parameter Library for Evaluation of Nuclear Data for Application in Nuclear Technology{close_quotes} aims to release a reference input file of various types of parameters for the evaluation of nuclear cross sections using nuclear model codes. Included in the parameter files are a collection of optical model potentials that are available in the literature to evaluate these cross sections. As part of this research program we assess the applicability of these potentials over a range of target mass and projectile energy.
Empirical model for electron impact ionization cross sections of neutral atoms
Energy Technology Data Exchange (ETDEWEB)
Talukder, M.R.; Bose, S. [Rajshahi Univ., Dept. of Applied Physics and Electronic Engineering (Bangladesh); Patoary, M.A.R.; Haque, A.K.F.; Uddin, M.A.; Basak, A.K. [Rajshahi Univ., Dept. of Physics (Bangladesh); Kando, M. [Shizuoka Univ., Graduate School of Electronic Science and Technology (Japan)
2008-02-15
A simple empirical formula is proposed for the rapid calculation of electron impact total ionization cross sections both for the open- and closed-shell neutral atoms considered in the range 1 {<=} Z {<=} 92 and the incident electron energies from threshold to about 10{sup 4} eV. The results of the present analysis are compared with the available experimental and theoretical data. The proposed model provides a fast method for calculating fairly accurate electron impact total ionization cross sections of atoms. This model may be a prudent choice, for the practitioners in the field of applied sciences e.g. in plasma modeling, due to its simple inherent structure. (authors)
Floodplain Cross Section Lines
Department of Homeland Security — This table is required for any Digital Flood Insurance Rate Map database where cross sections are shown on the Flood Insurance Rate Map (FIRM). Normally any FIRM...
High-energy suppression of the Higgsstrahlung cross-section in the Minimal Composite Higgs Model
Hartling, Katy
2012-01-01
If the Higgs boson is composite, signs of this compositeness should appear via a formfactor-like suppression of Higgs scattering cross sections at momentum transfers above the compositeness scale. We explore this by computing the cross section for e+e- ---> ZH (Higgsstrahlung) in a warped five-dimensional gauge-Higgs unification model known as the Minimal Composite Higgs Model (MCHM). We observe that the Higgsstrahlung cross section in the MCHM is strongly suppressed compared to that in the Standard Model at center-of-mass energies above the scale of the first Kaluza-Klein excitations, due to cancellations among the contributions of successive Z boson Kaluza-Klein modes. We also show that the magnitude and sign of the coupling of the first Kaluza-Klein mode can be measured at a future electron-positron collider such as the proposed International Linear Collider or Compact Linear Collider.
Effect of cross-section models on the validity of sterile neutrino mixing limits
Stowell, Patrick; Cartwright, Susan
2015-01-01
Charged-Current Quasi-Elastic (CCQE) neutrino scattering is the signal channel for sterile neutrino oscillation experiments. Recent cross-section measurements have made it clear that the current understanding of this channel in the few-GeV region is incomplete, and several sophisticated theoretical models have been proposed to tackle this issue, although it is not clear which model best describes the global dataset. In this paper we argue that the current uncertainty surrounding CCQE cross-sections is a serious problem for experiments seeking to produce sterile neutrino limits. We perform a sterile neutrino analysis with published MINERvA data as an illustrative example. We highlight the need for caution in interpreting sterile neutrino limits given the context of incomplete cross-section model information.
Analytic model of acoustic streaming in thermoacoustic waveguides with slowly varying cross-section
Institute of Scientific and Technical Information of China (English)
FAN Yuxian; LIU Ke; YANG Jun
2012-01-01
An analytic model of acoustic streaming generated in two-dimensional thermoa- coustic waveguides with slowly varying cross-section was developed for more general applica- tions. The analytical solutions of acoustic streaming characteristics in the closed straight tube and the annular tube are given based on the model. The solution for the closed straight tube can be applied to the case with any transverse scale. The solution for the annular tube is obtained under the assumption that the width of the varying cross-section part is much larger than the viscous and thermal penetration depths. The effects of cross-section variation, time-averaged temperature distribution and components of sound field are reflected in the analytic solutions. The magnitude and distribution of acoustic streaming velocity vary with the characteristic scale of the waveguides. The analytic model of acoustic streaming can be applied in research under thermoacoustic and other physical backgrounds.
Charged-current inclusive neutrino cross sections in the SuperScaling model
Energy Technology Data Exchange (ETDEWEB)
Ivanov, M. V., E-mail: martin.inrne@gmail.com [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Grupo de Física Nuclear, Departamento de Física Atómica, Molecular y Nuclear, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid E-28040 (Spain); Megias, G. D.; Caballero, J. A. [Departamento de Física Atómica, Molecular y Nuclear, Universidad de Sevilla, 41080 Sevilla (Spain); González-Jiménez, R. [Department of Physics and Astronomy, Ghent University, Proeftuinstraat 86, B-9000 Gent (Belgium); Moreno, O.; Donnelly, T. W. [Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Barbaro, M. B. [Dipartimento di Fisica, Università di Torino and INFN, Sezione di Torino, Via P. Giuria 1, 10125 Torino (Italy); Antonov, A. N. [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Moya de Guerra, E.; Udías, J. M. [Grupo de Física Nuclear, Departamento de Física Atómica, Molecular y Nuclear, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid E-28040 (Spain)
2016-03-25
SuperScaling model (SuSA) predictions to neutrino-induced charged-current π{sup +} production in the Δ-resonance region are explored under MiniBooNE experimental conditions. The SuSA charged-current π{sup +} results are in good agreement with data on neutrino flux-averaged double-differential cross sections. The SuSA model for quasielastic scattering and its extension to the pion production region are used for predictions of charged-current inclusive neutrino-nucleus cross sections. Results are also compared with the T2K experimental data for inclusive scattering.
Fragmentation cross-sections and model uncertainties in Cosmic Ray propagation physics
Tomassetti, Nicola
2015-01-01
Abundances and energy spectra of cosmic ray nuclei are being measured with high accuracy by the AMS experiment. These observations can provide tight constraints to the propagation models of galactic cosmic rays. In the view of the release of these data, I present an evaluation of the model uncertainties associated to the cross-sections for secondary production of Li-Be-B nuclei in cosmic rays. I discuss the role of cross section uncertainties in the calculation of the boron-to-carbon and beryllium-to-boron ratios, as well as their impact in the determination of the cosmic-ray transport parameters.
Fast-neutron total and scattering cross sections of sup 58 Ni and nuclear models
Energy Technology Data Exchange (ETDEWEB)
Smith, A.B.; Guenther, P.T.; Whalen, J.F. (Argonne National Lab., IL (United States)); Chiba, S. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment)
1991-07-01
The neutron total cross sections of {sup 58}Ni were measured from {approx} 1 to > 10 MeV using white-source techniques. Differential neutron elastic-scattering cross sections were measured from {approx} 4.5 to 10 MeV at {approx} 0.5 MeV intervals with {ge} 75 differential values per distribution. Differential neutron inelastic-scattering cross sections were measured, corresponding to fourteen levels with excitations up to 4.8 MeV. The measured results, combined with relevant values available in the literature, were interpreted in terms of optical-statistical and coupled-channels model using both vibrational and rotational coupling schemes. The physical implications of the experimental results nd their interpretation are discussed in the contexts of optical-statistical, dispersive-optical, and coupled-channels models. 61 refs.
Stark, Glenn; Smith, P. L.
2008-09-01
Our research program is dedicated to the measurement and modeling of vacuum ultraviolet and UV molecular photoabsorption cross sections with the highest practical resolution. It supports efforts to interpret and model observations of planetary atmospheres. Measurement and modeling efforts on molecular nitrogen, carbon dioxide, sulfur dioxide, and diatomic sulfur are in progress. N2: We focus on the measurement of line f-values and line widths within the complex spectrum between 80 and 100 nm. Our measurements are incorporated into a theoretical model of the absorption spectrum of N2 which has established the mechanisms responsible for predissociation and reproduces all observed features in 14N2 and its isotopomers as a function of temperature. CO2: The photodissociation of CO2 is a fundamental photochemical process in the atmospheres of Mars and Venus. Our research centers on the measurement of high resolution cross sections from 91 to 120 nm. We have completed measurements at 295 K and 195 K over the 106 to 120 nm region, and we are analyzing recent measurements of cross sections between 91 and 106 nm. SO2: We provide astronomers with high-resolution cross section data for the complex ultraviolet absorption spectrum between 198 and 325 nm. Using the Imperial College VUV Fourier transform spectrometer, we have completed and published room temperature cross sections, and we are completing work on low-temperature measurements over the same spectral region. S2: Interpretations of atmospheric (Io, Jupiter, cometary comae) S2 absorption features are hindered by a complete lack of laboratory cross section data in the ultraviolet. We are beginning an effort to quantify the photoabsorption spectrum of S2 from 200 to 300 nm based on theoretical calculations and laboratory measurements. Coupled-channel calculations will be complemented by measurements of the absorption spectrum of S2 at high resolution.
Stark, G.; Smith, P. L.; Lewis, B. R.; Heays, A.; Blackie, D.; Pickering, J.
2010-12-01
Our research program comprises the measurement and modeling of ultraviolet molecular photoabsorption cross sections with the highest practical resolution. It supports efforts to interpret and model observations of planetary atmospheres. Measurement and modeling efforts on molecular nitrogen, sulfur dioxide, diatomic sulfur, and carbon dioxide are in progress. Molecular Nitrogen: We focus on the measurement of line f-values and line widths within the complex spectrum between 80 and 100 nm. Our measurements are incorporated into a theoretical model of the absorption spectrum of N2 which has established the mechanisms responsible for predissociation and reproduces all observed features in 14N2 and its isotopomers as a function of temperature. Sulfur Dioxide: We provide astronomers with high-resolution cross section data for the complex ultraviolet SO2 absorption spectrum. Using the Imperial College VUV Fourier transform spectrometer, we have completed and published room temperature cross sections from 198 to 325 nm and 160 K cross sections from 199 to 220 nm. We have completed work on further low-temperature measurements from 220 to 325 nm. Diatomic Sulfur: Interpretations of atmospheric (Io, Jupiter, cometary comae) S2 absorption features are hindered by a complete lack of laboratory cross section data in the ultraviolet. We are working to quantify the photoabsorption spectrum of S2 from 200 to 300 nm based on laboratory measurements and theoretical calculations. We have designed an experimental apparatus to produce a stable column of S2 vapor. Measurements of the absorption spectrum of S2 at high resolution will be complemented by coupled-channel calculations. Carbon Dioxide: The photodissociation of CO2 is a fundamental photochemical process in the atmospheres of Mars and Venus. Our research centers on the measurement of high resolution cross sections from 87 to 120 nm. We have completed measurements at 295 K and 195 K over the 106 to 120 nm region, and we have
Stark, Glenn; Smith, P. L.; Lewis, B. R.; Heays, A. N.; Pickering, J.; Blackwell-Whitehead, R.; Blackie, D.
2008-09-01
Our research program is dedicated to the measurement and modeling of vacuum ultraviolet and UV molecular photoabsorption cross sections with the highest practical resolution. It supports efforts to interpret and model observations of planetary atmospheres. Measurement and modeling efforts on molecular nitrogen, carbon dioxide, sulfur dioxide, and diatomic sulfur are in progress. N2: We focus on the measurement of line f-values and line widths within the complex spectrum between 80 and 100 nm. Our measurements are incorporated into a theoretical model of the absorption spectrum of N2 which has established the mechanisms responsible for predissociation and reproduces all observed features in 14N2 and its isotopomers as a function of temperature. CO2: The photodissociation of CO2 is a fundamental photochemical process in the atmospheres of Mars and Venus. Our research centers on the measurement of high resolution cross sections from 91 to 120 nm. We have completed measurements at 295 K and 195 K over the 106 to 120 nm region, and we are analyzing recent measurements of cross sections between 91 and 106 nm. SO2: We provide astronomers with high-resolution cross section data for the complex ultraviolet absorption spectrum between 198 and 325 nm. Using the Imperial College VUV Fourier transform spectrometer, we have completed and published room temperature cross sections, and we are completing work on low-temperature measurements over the same spectral region. S2: Interpretations of atmospheric (Io, Jupiter, cometary comae) S2 absorption features are hindered by a complete lack of laboratory cross section data in the ultraviolet. We are beginning an effort to quantify the photoabsorption spectrum of S2 from 200 to 300 nm based on theoretical calculations and laboratory measurements. Coupled-channel calculations will be complemented by measurements of the absorption spectrum of S2 at high resolution.
Mathematical Model of Thermo Hydraulic Processes in Venturi Apparatus with Rectangular Cross Section
Directory of Open Access Journals (Sweden)
Cvete B. Dimitrieska
2016-05-01
Full Text Available The cleaning processes of polluted gases in high velocity gas streams based on water flushing, as well as the heat and mass transfer mechanisms in Venturi apparatus, are well known in engineering investigations. Flowing processes in Venturi apparatus with rectangular cross section are also not unknown process in scientific literature. The modeling of flow process in Venturi apparatus with rectangular cross section with real shape and dimensions are related in this paper. Thereby, special attention is paid to the reviewing of the flowing processes in gas-flow path, particularly in the confusor, the throat and the diffuser of the Venturi apparatus.
Accuracy of Reaction Cross Section for Exotic Nuclei in Glauber Model Based on MCMC Diagnostics
Rueter, Keiti; Novikov, Ivan
2017-01-01
Parameters of a nuclear density distribution for an exotic nuclei with halo or skin structures can be determined from the experimentally measured reaction cross-section. In the presented work, to extract parameters such as nuclear size information for a halo and core, we compare experimental data on reaction cross-sections with values obtained using expressions of the Glauber Model. These calculations are performed using a Markov Chain Monte Carlo algorithm. We discuss the accuracy of the Monte Carlo approach and its dependence on k*, the power law turnover point in the discreet power spectrum of the random number sequence and on the lag-1 autocorrelation time of the random number sequence.
Towards a construction of inclusive collision cross-sections in massless Nelson's model
Dybalski, Wojciech
2011-01-01
The conventional approach to the infrared problem in perturbative quantum electrodynamics relies on the concept of inclusive collision cross-sections. A non-perturbative variant of this notion was introduced in algebraic quantum field theory. Relying on these insights, we take first steps towards a non-perturbative construction of inclusive collision cross-sections in massless Nelson's model. We show that our proposal is consistent with the standard scattering theory in the absence of the infrared problem and discuss its status in the infrared-singular case.
How to Use Benchmark and Cross-section Studies to Improve Data Libraries and Models
Wagner, V.; Suchopár, M.; Vrzalová, J.; Chudoba, P.; Svoboda, O.; Tichý, P.; Krása, A.; Majerle, M.; Kugler, A.; Adam, J.; Baldin, A.; Furman, W.; Kadykov, M.; Solnyshkin, A.; Tsoupko-Sitnikov, S.; Tyutyunikov, S.; Vladimirovna, N.; Závorka, L.
2016-06-01
Improvements of the Monte Carlo transport codes and cross-section libraries are very important steps towards usage of the accelerator-driven transmutation systems. We have conducted a lot of benchmark experiments with different set-ups consisting of lead, natural uranium and moderator irradiated by relativistic protons and deuterons within framework of the collaboration “Energy and Transmutation of Radioactive Waste”. Unfortunately, the knowledge of the total or partial cross-sections of important reactions is insufficient. Due to this reason we have started extensive studies of different reaction cross-sections. We measure cross-sections of important neutron reactions by means of the quasi-monoenergetic neutron sources based on the cyclotrons at Nuclear Physics Institute in Řež and at The Svedberg Laboratory in Uppsala. Measurements of partial cross-sections of relativistic deuteron reactions were the second direction of our studies. The new results obtained during last years will be shown. Possible use of these data for improvement of libraries, models and benchmark studies will be discussed.
Earnings Profiles of Department Heads: Comparing Cross-Sectional and Panel Models.
Ragan, James F., Jr.; Rehman, Qazi Najeeb
1996-01-01
A cross-sectional study of 842 faculty who served as department heads between 1965-92 was compared with 170 in a panel study for whom earnings were estimated using a personal effects model. The average chair received a 12% wage premium for administrative service. Skill depreciation was most severe and wage growth most adversely affected in the…
Testing Cross-Sectional Correlation in Large Panel Data Models with Serial Correlation
Directory of Open Access Journals (Sweden)
Badi H. Baltagi
2016-11-01
Full Text Available This paper considers the problem of testing cross-sectional correlation in large panel data models with serially-correlated errors. It finds that existing tests for cross-sectional correlation encounter size distortions with serial correlation in the errors. To control the size, this paper proposes a modification of Pesaran’s Cross-sectional Dependence (CD test to account for serial correlation of an unknown form in the error term. We derive the limiting distribution of this test as N , T → ∞ . The test is distribution free and allows for unknown forms of serial correlation in the errors. Monte Carlo simulations show that the test has good size and power for large panels when serial correlation in the errors is present.
Rovibrationally Inelastic Atom-Molecule Collision Cross Sections from a Hard Sphere Model
Lashner, Jacob; Stewart, Brian
2016-05-01
Hard-shell models have long been used to elucidate the principal features of molecular energy transfer and exchange reaction in the A + BC system. Nevertheless, no three-dimensional hard-shell calculation of inelastic collision cross sections has been reported. This work aims to fill that void. A particular motivation comes from our experimental results, which show the importance of equatorial impacts in the vibrational excitation process. Working with the simple hard-sphere model, we incorporated secondary impacts, defined as those in which A strikes C after striking B. Such collisions are important in systems such as Li2 - X, in which vibrational energy transfer occurs principally through side impacts. We discuss the complexity this adds to the model and present fully three-dimensional cross sections for rovibrational excitation of an initially stationary molecule in the homonuclear A + B2 system, examining the cross section as a function of the masses and radii of the atoms. We show how the features in the cross section evolve as these parameters are varied and calculate the contribution of secondary (near-equatorial) impacts to the dynamics. We compare with recent measurements in our laboratory and with the results of quasiclassical trajectories.
Spatial profiles of positrons injected at low energies into water: influence of cross section models
Tattersall, Wade J.; Cocks, Daniel G.; Boyle, Gregory J.; Brunger, Michael J.; Buckman, Stephen J.; García, Gustavo; Petrović, Zoran Lj; Sullivan, James P.; White, Ronald D.
2017-04-01
We present a collated set of interaction cross sections for positrons in water, and study how the choice of ionisation energy sharing and of anisotropy in elastic cross sections influences low-energy spatial transport. A Monte Carlo code has been developed to model the transport of a beam of positrons injected at 60 eV into water, in which we compare several ionisation energy sharing models, and also vary the anisotropic scattering behaviour for elastic collisions. While the cross sections are primarily applicable to water vapour, we have investigated the inclusion of coherent elastic scattering which is present in liquid water. We present comparative profiles of positron number density, energy deposition, positronium formation, and secondary electron generation. Anisotropic scattering can increase radial diffusion by a factor of two, and a similar effect occurs as a result of coherent elastic scattering, though only at energies below the positronium formation threshold. The results emphasise the need for detailed knowledge of scattering cross sections that are differential in both scattering angles and energy transfer.
Theory of inclusive breakup cross section for Borromean nuclei within a four-body spectator model
Carlson, Brett V; Hussein, Mahir S
2016-01-01
We develop a model to treat the inclusive non-elastic break up reactions involving weakly bound three-cluster nuclei. Borromean, two-nucleon, halo nuclei are candidates of unstable three-fragments projectiles. The model is based on the theory of inclusive breakup reactions commonly employed in the treatment of incomplete fusion and surrogate method. The theory was developed in the 80's by Ichimura, Autern and Vincent (IAV) [Phys. Rev. C 32, 431 (1985)] \\cite{IAV1985}, Udagawa and Tamura (UT)[Phys. Rev. C 24, 1348 (1981)], \\cite{UT1981} and Hussein and McVoy (HM)[Nucl. Phys. A 445, 124 (1985)], \\cite{HM1985}. We extend these three-body theories to derive an expression for the fragment yield in the reaction $A\\,(a,b)\\,X$, where the projectile is $a = x_1 + x_2 + b$. The inclusive breakup cross section is found to be the sum of a generalized four-body form of the elastic breakup cross section plus the inclusive non-elastic breakup cross section which involves the "reaction" cross section of the participant fragm...
Unobserved Heterogeneity in the Binary Logit Model with Cross-Sectional Data and Short Panels
DEFF Research Database (Denmark)
Holm, Anders; Jæger, Mads Meier; Pedersen, Morten
This paper proposes a new approach to dealing with unobserved heterogeneity in applied research using the binary logit model with cross-sectional data and short panels. Unobserved heterogeneity is particularly important in non-linear regression models such as the binary logit model because, unlike...... in linear regression models, estimates of the effects of observed independent variables are biased even when omitted independent variables are uncorrelated with the observed independent variables. We propose an extension of the binary logit model based on a finite mixture approach in which we conceptualize...
Modeling and Analysis of a Piezoelectric Energy Harvester with Varying Cross-Sectional Area
Directory of Open Access Journals (Sweden)
Maiara Rosa
2014-01-01
Full Text Available This paper reports on the modeling and on the experimental verification of electromechanically coupled beams with varying cross-sectional area for piezoelectric energy harvesting. The governing equations are formulated using the Rayleigh-Ritz method and Euler-Bernoulli assumptions. A load resistance is considered in the electrical domain for the estimate of the electric power output of each geometric configuration. The model is first verified against the analytical results for a rectangular bimorph with tip mass reported in the literature. The experimental verification of the model is also reported for a tapered bimorph cantilever with tip mass. The effects of varying cross-sectional area and tip mass on the electromechanical behavior of piezoelectric energy harvesters are also discussed. An issue related to the estimation of the optimal load resistance (that gives the maximum power output on beam shape optimization problems is also discussed.
Electron scattering cross sections for the modelling of oxygen-containing plasmas
Lemos Alves, Luís; Coche, Philippe; Ridenti, Marco Antonio; Guerra, Vasco
2016-05-01
This work proposes a set of electron scattering cross sections for molecular and atomic oxygen, with interest for the modelling of oxygen-containing plasmas. These cross sections, compiled for kinetic energies up to 1 keV, are part of the IST-LISBON database with LXCat, being used as input data to the LoKI (LisbOn KInetics) numerical code. The cross sections for ground-state molecular oxygen describe elastic and inelastic collision mechanisms, the latter including rotational excitations/de-excitations (treated using either a discrete or a continuous approach), vibrational and electronic excitations (including dissociation), dissociative attachment and ionisation. This set yields calculated swarm parameters that reproduce measurements within 5-20% (transport parameters) and within a factor of 2 difference (Townsend coefficients), for reduced electric fields in the range 10-3-103 Td. The cross sections describing the kinetics of atomic oxygen by electron-impact comprise elastic mechanisms, electronic excitation and ionisation from O(3P) ground-state, dissociation of O2(X,a,b) (including dissociative ionisation and attachment) and of O3, and detachment. These cross sections are indirectly validated, together with other elementary data for oxygen, by comparing the densities of O((4S0)3p 5P) obtained from the self-consistent modelling and from calibrated optical emission spectroscopy diagnostics of microwave-sustained micro-plasmas in dry air (80% N2: 20% O2), produced using a surface-wave excitation (2.45 GHz frequency) within a small radius capillary (R = 345 μm) at low pressure (p = 300 Pa). The calculated densities are in good qualitative agreement with measurements, overestimating them by a factor ˜1.5. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.
Electron scattering cross sections for the modelling of oxygen-containing plasmas*
Alves, Luís Lemos; Coche, Philippe; Ridenti, Marco Antonio; Guerra, Vasco
2016-06-01
This work proposes a set of electron scattering cross sections for molecular and atomic oxygen, with interest for the modelling of oxygen-containing plasmas. These cross sections, compiled for kinetic energies up to 1 keV, are part of the IST-LISBON database with LXCat, being used as input data to the LoKI (LisbOn KInetics) numerical code. The cross sections for ground-state molecular oxygen describe elastic and inelastic collision mechanisms, the latter including rotational excitations/de-excitations (treated using either a discrete or a continuous approach), vibrational and electronic excitations (including dissociation), dissociative attachment and ionisation. This set yields calculated swarm parameters that reproduce measurements within 5-20% (transport parameters) and within a factor of 2 difference (Townsend coefficients), for reduced electric fields in the range 10-3-103 Td. The cross sections describing the kinetics of atomic oxygen by electron-impact comprise elastic mechanisms, electronic excitation and ionisation from O(3P) ground-state, dissociation of O2(X,a,b) (including dissociative ionisation and attachment) and of O3, and detachment. These cross sections are indirectly validated, together with other elementary data for oxygen, by comparing the densities of O((4S0)3 p 5P) obtained from the self-consistent modelling and from calibrated optical emission spectroscopy diagnostics of microwave-sustained micro-plasmas in dry air (80% N2: 20% O2), produced using a surface-wave excitation (2.45 GHz frequency) within a small radius capillary ( R = 345 μm) at low pressure ( p = 300 Pa). The calculated densities are in good qualitative agreement with measurements, overestimating them by a factor ˜1.5.
Cross-section model for cold neutron scattering in solid and liquid methane
Morishima, N
2002-01-01
Incoherent neutron scattering cross-sections for solid CH sub 4 in the temperature range of 20.4-90.7 K and liquid CH sub 4 at temperatures between 90.7 and 111.7 K are evaluated. A space-time correlation approach is used to describe a double-differential scattering cross-section which is basically expressed by a generalized frequency distribution. The cross-section model includes molecular translations and rotations as well as intramolecular vibrations. The former are concerned with very short-time free-gas like translation, short-lived vibration and long-time diffusion (only in liquid state). The latter consists of short-time free rotation and long-time isotropic rotational diffusion. Numerical calculations on double-differential and total cross-sections are carried out for incident neutron energies covered 0.1 mu eV to 10 eV. Good agreement with experimental results at many different temperatures is found.
Kendl, Alexander
2014-01-01
Turbulent transport of trace impurities impurities in the edge and scrape-off-layer of tokamak fusion plasmas is modelled by three dimensional electromagnetic gyrofluid computations including evolution of plasma profile gradients. The source function of impurity ions is dynamically computed from pre-determined measured and calculated electron impact ionization cross section data. The simulations describe the generation and further passive turbulent E-cross-B advection of the impurities by intermittent fluctuations and coherent filamentary structures (blobs) across the scrape-off-layer.
Magnetic cloud models with bent and oblate cross-section boundaries
Démoulin, P.; Dasso, S.
2009-11-01
Context: Magnetic clouds (MCs) are formed by magnetic flux ropes that are ejected from the Sun as coronal mass ejections. These structures generally have low plasma beta and travel through the interplanetary medium interacting with the surrounding solar wind. Thus, the dynamical evolution of the internal magnetic structure of a MC is a consequence of both the conditions of its environment and of its own dynamical laws, which are mainly dominated by magnetic forces. Aims: With in-situ observations the magnetic field is only measured along the trajectory of the spacecraft across the MC. Therefore, a magnetic model is needed to reconstruct the magnetic configuration of the encountered MC. The main aim of the present work is to extend the widely used cylindrical model to arbitrary cross-section shapes. Methods: The flux rope boundary is parametrized to account for a broad range of shapes. Then, the internal structure of the flux rope is computed by expressing the magnetic field as a series of modes of a linear force-free field. Results: We analyze the magnetic field profile along straight cuts through the flux rope, in order to simulate the spacecraft crossing through a MC. We find that the magnetic field orientation is only weakly affected by the shape of the MC boundary. Therefore, the MC axis can approximately be found by the typical methods previously used (e.g., minimum variance). The boundary shape affects the magnetic field strength most. The measurement of how much the field strength peaks along the crossing provides an estimation of the aspect ratio of the flux-rope cross-section. The asymmetry of the field strength between the front and the back of the MC, after correcting for the time evolution (i.e., its aging during the observation of the MC), provides an estimation of the cross-section global bending. A flat or/and bent cross-section requires a large anisotropy of the total pressure imposed at the MC boundary by the surrounding medium. Conclusions: The
DEFF Research Database (Denmark)
Cai, Xiao-Xiao; Llamas-Jansa, Isabel; Mullet, Steven
2013-01-01
to reactor modelling. Before version 9.5, Geant4 HP thermal scattering model (i.e. the S(α; β) model ) supports only three bounded isotopes, namely, H in water and polyethylene, and C in graphite. Newly supported materials include D in heavy water, O and Be in beryllium oxide, H and Zr in zirconium hydride......, U and O in uranium dioxide, Al metal, Be metal, and Fe metal. The native HP cross section library G4NDL does not include data for elements with atomic number larger than 92. Therefore, transuranic elements, which have impacts for a realistic reactor, can not be simulated by the combination of the HP...
Energy deposition model based on electron scattering cross section data from water molecules
Energy Technology Data Exchange (ETDEWEB)
Munoz, A; Oiler, J C [Centra de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avenida Complutense 22, 28040 Madrid (Spain); Blanco, F [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, Avenida Complutense s.n., 28040 Madrid (Spain); Gorfinkiel, J D [Department of Physiscs and Astronomy, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Limao-Vieira, P [Departamento de Fisica, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Maira-Vidal, A; Borge, M J G; Tengblad, O [Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas (CSIC), Serrano 113-bis, 28006 Madrid, Spam (Spain); Huerga, C; Tellez, M [Hospital Universitario La Paz, paseo de la Castellana 261, 28046 Madrid (Spain); Garcia, G [Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones CientifIcas (CSIC), Serrano 113-bis, 28006 Madrid (Spain)], E-mail: g.garcia@imaff.cfmac.csic.es
2008-10-01
A complete set of electrons scattering cross sections by water molecules over a broad energy range, from the me V to the Me V ranges, is presented in this study. These data have been obtained by combining experiments and calculations and cover most relevant processes, both elastic and inelastic, which can take place in the considered energy range. A new Monte Carlo simulation programme has been developed using as input parameter these cross sectional data as well as experimental energy loss spectra. The simulation procedure has been applied to obtain electron tracks and energy deposition plots in water when irradiated by a Ru-106 plaque as those used for brachytherapy of ocular tumours. Finally, the low energy electron tracks provided by the present model have been compared with those obtained with other codes available in the literature.
Choi, S Y; Jang, J H; Song, H S; Park, Seong Chan
2001-01-01
We study the elastic scattering of the lightest neutralino with a nucleus in the framework of the minimal supersymmetric standard model (MSSM) with explicit flavor preserving CP violation, including the one-loop CP-violating neutral Higgs-boson mixing effects induced dominantly by the CP phases in the top and bottom (s)quark sectors. We construct the most general form of the effective Lagrangian for the neutralino-nucleus scattering in the limit of vanishing momentum transfers and then we perform a comprehensive analysis of the effects of the complex CP phases on the mass spectra of the lightest neutralino, neutral Higgs bosons and top squarks, and on the the spin-dependent and spin-independent neutralino-nucleus scattering cross section for three neucleus targets F, Si and Ge. The CP phases can reduce or enhance the neutralino-nucleus cross sections significantly, depending on the values of the real parameters in the MSSM.
Knott, Gene; Tuley, Michael
2004-01-01
This is the second edition of the first and foremost book on this subject for self-study, training, and course work. Radar cross section (RCS) is a comparison of two radar signal strengths. One is the strength of the radar beam sweeping over a target, the other is the strength of the reflected echo sensed by the receiver. This book shows how the RCS ?gauge? can be predicted for theoretical objects and how it can be measured for real targets. Predicting RCS is not easy, even for simple objects like spheres or cylinders, but this book explains the two ?exact? forms of theory so well that even a
Directory of Open Access Journals (Sweden)
Jian Lu
2011-08-01
Full Text Available Multilayered microresonators commonly use sensitive coating or piezoelectric layers for detection of mass and gas. Most of these microresonators have a variable cross-section that complicates the prediction of their fundamental resonant frequency (generally of the bending mode through conventional analytical models. In this paper, we present an analytical model to estimate the first resonant frequency and deflection curve of single-clamped multilayered microresonators with variable cross-section. The analytical model is obtained using the Rayleigh and Macaulay methods, as well as the Euler-Bernoulli beam theory. Our model is applied to two multilayered microresonators with piezoelectric excitation reported in the literature. Both microresonators are composed by layers of seven different materials. The results of our analytical model agree very well with those obtained from finite element models (FEMs and experimental data. Our analytical model can be used to determine the suitable dimensions of the microresonator’s layers in order to obtain a microresonator that operates at a resonant frequency necessary for a particular application.
Propagation Mechanism Modeling in the Near-Region of Arbitrary Cross-Sectional Tunnels
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Ke Guan
2012-01-01
Full Text Available Along with the increase of the use of working frequencies in advanced radio communication systems, the near-region inside tunnels lengthens considerably and even occupies the whole propagation cell or the entire length of some short tunnels. This paper analytically models the propagation mechanisms and their dividing point in the near-region of arbitrary cross-sectional tunnels for the first time. To begin with, the propagation losses owing to the free space mechanism and the multimode waveguide mechanism are modeled, respectively. Then, by conjunctively employing the propagation theory and the three-dimensional solid geometry, the paper presents a general model for the dividing point between two propagation mechanisms. It is worthy to mention that this model can be applied in arbitrary cross-sectional tunnels. Furthermore, the general dividing point model is specified in rectangular, circular, and arched tunnels, respectively. Five groups of measurements are used to justify the model in different tunnels at different frequencies. Finally, in order to facilitate the use of the model, simplified analytical solutions for the dividing point in five specific application situations are derived. The results in this paper could help deepen the insight into the propagation mechanisms in tunnels.
Statistical model analysis of α -induced reaction cross sections of 64Zn at low energies
Mohr, P.; Gyürky, Gy.; Fülöp, Zs.
2017-01-01
Background: α -nucleus potentials play an essential role in the calculation of α -induced reaction cross sections at low energies in the statistical model. Uncertainties of these calculations are related to ambiguities in the adjustment of the potential parameters to experimental elastic scattering angular distributions (typically at higher energies) and to the energy dependence of the effective α -nucleus potentials. Purpose: The present work studies cross sections of α -induced reactions for 64Zn at low energies and their dependence on the chosen input parameters of the statistical model calculations. The new experimental data from the recent Atomki experiments allow for a χ2-based estimate of the uncertainties of calculated cross sections at very low energies. Method: Recently measured data for the (α ,γ ), (α ,n ), and (α ,p ) reactions on 64Zn are compared to calculations in the statistical model. A survey of the parameter space of the widely used computer code talys is given, and the properties of the obtained χ2 landscape are discussed. Results: The best fit to the experimental data at low energies shows χ2/F ≈7.7 per data point, which corresponds to an average deviation of about 30% between the best fit and the experimental data. Several combinations of the various ingredients of the statistical model are able to reach a reasonably small χ2/F , not exceeding the best-fit result by more than a factor of 2. Conclusions: The present experimental data for 64Zn in combination with the statistical model calculations allow us to constrain the astrophysical reaction rate within about a factor of 2. However, the significant excess of χ2/F of the best fit from unity demands further improvement of the statistical model calculations and, in particular, the α -nucleus potential.
A Method for Creating a Three Dimensional Model from Published Geologic Maps and Cross Sections
Walsh, Gregory J.
2009-01-01
This brief report presents a relatively inexpensive and rapid method for creating a 3D model of geology from published quadrangle-scale maps and cross sections using Google Earth and Google SketchUp software. An example from the Green Mountains of Vermont, USA, is used to illustrate the step by step methods used to create such a model. A second example is provided from the Jebel Saghro region of the Anti-Atlas Mountains of Morocco. The report was published to help enhance the public?s ability to use and visualize geologic map data.
Frequency Extrapolation by Floating Genetic Algorithm Based on GTD Model for Radar Cross Section
Institute of Scientific and Technical Information of China (English)
YANG Zhenglong; FANG Dagang; SHENG Weixing; LIU Tiejun; ZHUANG Jing
2001-01-01
A frequency extrapolation scheme isdeveloped to effectively predict radar cross section us-ing floating genetic algorithm based on the GTD (ge-ometry theory of diffraction) model. The parameter-ized model to extrapolate the frequency response tohigher (or lower) frequency band is used and somepractical targets are calculated to test the effective-ness of the method. The influence of extrapolationon the range profile is studied. Furthermore, the re-lationship between the fitting precision and extrap-olation ability is considered. Different extrapolationprocedures are discussed.
NN S-Wave Elastic Cross Section and Possible Bound States in a Constituent Quark Model
Institute of Scientific and Technical Information of China (English)
PANG Hou-Rong; PING Jia-Lun; WANG Fan
2008-01-01
In the framework of a chiral constituent quark model, considering the contributions of π annihilation and one-gluon annihilation, the proton-antiproton s-wave elastic scattering cross section experimental data can be reproduced by adjusting properly one-gluon annihilation coupling constant. After fixing the model parameters, we perform a dynamical calculation for all possible s-wave nucleon-antinucleon states. The results show that there is no s-wave bound state as indicated by a strong enhancement at threshold of pp in J/ψ and B decay.
Terahertz radar cross section measurements
DEFF Research Database (Denmark)
Iwaszczuk, Krzysztof; Heiselberg, Henning; Jepsen, Peter Uhd
2010-01-01
We perform angle- and frequency-resolved radar cross section (RCS) measurements on objects at terahertz frequencies. Our RCS measurements are performed on a scale model aircraft of size 5-10 cm in polar and azimuthal configurations, and correspond closely to RCS measurements with conventional radar...
Energy Technology Data Exchange (ETDEWEB)
Ivascu, M.; Avrigeanu, M.; Avrigeanu, V.
1986-01-01
Calculated data are presented on (n,p), (n,n'p) and (n,2n) reaction cross sections for stable titanium isotopes in the energy range from threshold up to 20 MeV. An improved preequilibrium approach, allowing a unitary use of preequilibrium and equilibrium emission parameters, has increased the agreement between calculated and experimental cross sections.
Production cross sections of the superheavy nucleus 117 based on the dinuclear system model
Institute of Scientific and Technical Information of China (English)
ZHAO Wei-Juan; ZHANG Yong-Qi; WANG Hua-Lei; SONG Li-Tao; LI Lu-Lu
2010-01-01
Within the framework of the dinuclear system model,the capture of two colliding nuclei,and the formation and de-excitation process of a compound nucleus are described by using an empirical coupled channel model,solving the master equation numerically and the statistical evaporation model,respectively.In the process of heavy-ion capture and fusion to synthesize superheavy nuclei,the barrier distribution func-tion is introduced and averaging collision orientations are considered.Based on this model,the production cross sections of the cold fusion system 76-82Se+209Bi and the hot fusion systems 55Mn+238U,51V-+244Pu,59 Co+232 Th,48 Ca+247-249 Bk and 45 Sc+246-248 Cm are calculated.The isotopic dependence of the largest production cross sections is analyzed briefly,and the optimal projectile-target combination and excitation energy of the ln-4n evaporation channels are proposed.It is shown that the hot fusion systems 48Ca+247 249Bk in the3n evaporation channels and 45Sc+248Cm in the 2n-4n channels are optimal for synthesizing the superheavy element 117.
Cross sections of proton- and neutron-induced reactions by the Liège intranuclear cascade model
Chen, Jian; Dong, Tiekuang; Ren, Zhongzhou
2016-06-01
The purpose of the paper is mainly to test the validity of the Liège intranuclear cascade (INCL) model in calculating the cross sections of proton-induced reactions for cosmogenic nuclei using the newly compiled database of proton cross sections. The model calculations of 3He display the rising tendency of cross sections with the increase of energy, in accordance with the experimental data. Meanwhile, the differences between the theoretical results and experimental data of production cross sections (10Be and 26Al) are generally within a factor of 3, meaning that the INCL model works quite well for the proton-induced reactions. Based on the good agreement, we predict the production cross sections of 26Al from reactions n + 27Al, n + 28Si, and n + 40Ca and those of 10Be from reactions n + 16O and n + 28Si. The results also show a good agreement with a posteriori excitation functions.
DEFF Research Database (Denmark)
Christensen, René
2011-01-01
cylindrical tube the characteristic length is the radius. A triangular cross-section does not have a characteristic length, but as will be shown in this paper the model can in fact be used as long as 1) the cross-sectional pressure is constant and 2) a characteristic impedance and propagation wavenumber can...
Model-independent determination of doublet and quartet cross sections in Nd fusion
Ramachandran, G
2001-01-01
A model-independent theoretical formalism is outlined to describe Nd fusion in terms of irreducible tensor amplitudes labelled by the initial channel spins s=((1)/(2)),((3)/(2)). A comprehensive form for the initial spin density matrix rho is given in the channel spin representation, when both the beam and target are polarized. It is then suggested that an incisive study of Nd fusion may be carried out employing a polarized beam on a polarized target, leading to the determination of the differential cross sections for the doublet and quartet states individually.
Kozlov, Alex; Quiney, Harry
2016-01-01
We describe a method for the calculation of photoionization cross-sections using square-integrable amplitudes obtained from the diagonalization of finite-basis set representations of the electronic Hamiltonian. Three examples are considered: a model example in which the final state is a free particle, the hydrogen atom and neutral atomic sodium. The method exploits the Whittaker-Shannon-Kotel'nikov sampling theorem, which is widely used in digital signal sampling and reconstruction. The approach reproduces known data with very good accuracy and converges to the exact solution with increase of the basis set size.
Kozlov, A.; Saha, S.; Quiney, H. M.
2017-01-01
We describe a method for the calculation of photoionization cross-sections using square-integrable amplitudes obtained from the diagonalization of finite-basis set representations of the electronic Hamiltonian. Three examples are considered: a model example in which the final state is a free particle, the hydrogen atom and neutral atomic sodium. The method exploits the Whittaker-Shannon-Kotel’nikov sampling theorem, which is widely used in digital signal sampling and reconstruction. The approach reproduces known data with very good accuracy and converges to the exact solution with increase of the basis set size.
Global Study of Magnetic Clouds Using An Elliptical Cross Section Model
Hidalgo, M. A.; Nieves-Chinchilla, T.; Cid, C.; Sequeiros, J.
We present preliminary results on the analisis of plasma and magnetic field in mag- netic clouds. This work extends to plasma behaviour an already published model for the magnetic field of a magnetic cloud with an elliptical cross section. The elliptical shape assumed for the magnetic cloud has been introduced to have into account its interaccion with the solar wind as it travels through the interplanetary medium. We present the fitting of theoretical expressions to the three GSE components of the mag- netic field vector and to the solar wind electron pressure tensor for several encounters of the WIND spacecraft with magnetic clouds events.
New Arsenic Cross Section Calculations
Energy Technology Data Exchange (ETDEWEB)
Kawano, Toshihiko [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-03-04
This report presents calculations for the new arsenic cross section. Cross sections for ^{73,74,75} As above the resonance range were calculated with a newly developed Hauser-Feshbach code, CoH3.
Photoproduction total cross section and shower development
Cornet, F; Grau, A; Pancheri, G; Sciutto, S J
2015-01-01
The total photoproduction cross section at ultra-high energies is obtained using a model based on QCD minijets and soft-gluon resummation and the ansatz that infrared gluons limit the rise of total cross sections. This cross section is introduced into the Monte Carlo system AIRES to simulate extended air-showers initiated by cosmic ray photons. The impact of the new photoproduction cross section on common shower observables, especially those related to muon production, is compared with previous results.
Improvement of Axial Reflector Cross Section Generation Model for PWR Core Analysis
Energy Technology Data Exchange (ETDEWEB)
Shim, Cheon Bo; Lee, Kyung Hoon; Cho, Jin Young [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2016-10-15
This paper covers the study for improvement of axial reflector XS generation model. In the next section, the improved 1D core model is represented in detail. Reflector XS generated by the improved model is compared to that of the conventional model in the third section. Nuclear design parameters generated by these two XS sets are also covered in that section. Significant of this study is discussed in the last section. Two-step procedure has been regarded as the most practical approach for reactor core designs because it offers core design parameters quite rapidly within acceptable range. Thus this approach is adopted for SMART (System-integrated Modular Advanced Reac- Tor) core design in KAERI with the DeCART2D1.1/ MASTER4.0 (hereafter noted as DeCART2D/ MASTER) code system. Within the framework of the two-step procedure based SMART core design, various researches have been studied to improve the core design reliability and efficiency. One of them is improvement of reflector cross section (XS) generation models. While the conventional FA/reflector two-node model used for most core designs to generate reflector XS cannot consider the actual configuration of fuel rods that intersect at right angles to axial reflectors, the revised model reflects the axial fuel configuration by introducing the radially simplified core model. The significance of the model revision is evaluated by observing HGC generated by DeCART2D, reflector XS, and core design parameters generated by adopting the two models. And it is verified that about 30 ppm CBC error can be reduced and maximum Fq error decreases from about 6 % to 2.5 % by applying the revised model. Error of AO and axial power shapes are also reduced significantly. Therefore it can be concluded that the simplified 1D core model improves the accuracy of the axial reflector XS and leads to the two-step procedure reliability enhancement. Since it is hard for core designs to be free from the two-step approach, it is necessary to find
Optical model predictions for total cross sections for scattering of neutrons from {sup 40}Ca
Energy Technology Data Exchange (ETDEWEB)
Chinn C.R.; Elster, C.; Thaler, R.M.
1993-10-01
Measurements of neutron total cross sections are both extensive and extremely accurate. Although they should place a strong constraint on theoretically constructed optical models, there are relatively few comparisons of optical model predictions with those experiments. We have calculated total cross sections for neutron scattering from {sup 40}Ca as a function of energy from 100 - 600 MeV laboratory energy with a microscopic first order optical potential derived within the framework of the Watson expansion. Although the results are already in qualitative agreement with the data, the inclusion of medium corrections to the propagator using a recently derived microscopic mean field approach, is essential for correctly predicting the energy dependence given by the experiment. In the region below 200 MeV, where our off-shell tp calculations over predict the experiment, the modification due to the nuclear medium reduces the calculated values, whereas above 200 MeV, these corrections tend to compensate for the under prediction of the off-shell t{rho} results.
Model for neutron total cross-section at low energies for nuclear grade graphite
Energy Technology Data Exchange (ETDEWEB)
Galván Josa, V.M. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), FaMAF, Universidad Nacional de Córdoba (Argentina); Dawidowski, J., E-mail: javier@cab.cnea.gov.ar [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Comisión Nacional de Enegía Atómica-Universidad Nacional de Cuyo (Argentina); Santisteban, J.R.; Malamud, F. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Comisión Nacional de Enegía Atómica-Universidad Nacional de Cuyo (Argentina); Oliveira, R.G. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), CIQUIBIC, Fac. Cs. Químicas, Universidad Nacional de Córdoba (Argentina)
2015-04-21
At subthermal neutron energies, polycrystalline graphite shows a large total cross-section due to small angle scattering processes. In this work, a new methodology to determine pore size distributions through the neutron transmission technique at subthermal energies is proposed and its sensitivity is compared with standard techniques. A simple model based on the form factor for spherical particles, normally used in the Small Angle Neutron Scattering technique, is employed to calculate the contribution of small angle effect to the total scattering cross-section, with the width and center of the radii distributions as free parameters in the model. Small Angle X-ray Scattering experiments were performed to compare results as a means to validate the method. The good agreement reached reveals that the neutron transmission technique is a useful tool to explore small angle scattering effects. This fact can be exploited in situations where large samples must be scanned and it is difficult to investigate them with conventional methods. It also opens the possibility to apply this method in energy-resolved neutron imaging. Also, since subthermal neutron transmission experiments are perfectly feasible in small neutron sources, the present findings open new possibilities to the work done in such kind of facilities.
Pomeron pole plus grey disk model: Real parts, inelastic cross sections and LHC data
Roy, S. M.
2017-01-01
I propose a two component analytic formula F (s , t) =F (1) (s , t) +F (2) (s , t) for (ab → ab) + (a b bar → a b bar) scattering at energies ≥ 100 GeV, where s , t denote squares of c.m. energy and momentum transfer. It saturates the Froissart-Martin bound and obeys Auberson-Kinoshita-Martin (AKM) [1,2] scaling. I choose ImF (1) (s , 0) + ImF (2) (s , 0) as given by Particle Data Group (PDG) fits [3,4] to total cross sections, corresponding to simple and triple poles in angular momentum plane. The PDG formula is extended to non-zero momentum transfers using partial waves of ImF (1) and ImF (2) motivated by Pomeron pole and 'grey disk' amplitudes and constrained by inelastic unitarity. ReF (s , t) is deduced from real analyticity: I prove that ReF (s , t) / ImF (s , 0) → (π / ln s) d / dτ (τImF (s , t) / ImF (s , 0)) for s → ∞ with τ = t(lns) 2 fixed, and apply it to F (2). Using also the forward slope fit by Schegelsky-Ryskin [5], the model gives real parts, differential cross sections for (- t) 0.5 TeV, with PDG2013 [4] total cross sections, and Schegelsky-Ryskin slopes [5] as input, σinel (s) = 22.6 + . 034 lns + . 158(lns) 2 mb, and σinel /σtot → 0.56, s → ∞, where s is in GeV2 units. Continuation to positive t indicates an 'effective' t-channel singularity at ∼(1.5 GeV) 2, and suggests that usual Froissart-Martin bounds are quantitatively weak as they only assume absence of singularities upto 4 mπ2.
Introduction to the physics of the total cross section at LHC. A review of data and models
Pancheri, Giulia; Srivastava, Yogendra N.
2017-03-01
This review describes the development of the physics of hadronic cross sections up to recent LHC results and cosmic ray experiments. We present here a comprehensive review - written with a historical perspective - about total cross sections from medium to the highest energies explored experimentally and studied through a variety of methods and theoretical models for over 60 years. We begin by recalling the analytic properties of the elastic amplitude and the theorems about the asymptotic behavior of the total cross section. A discussion of how proton-proton cross sections are extracted from cosmic rays at higher than accelerator energies and help the study of these asymptotic limits, is presented. This is followed by a description of the advent of particle colliders, through which high energies and unmatched experimental precisions have been attained. Thus the measured hadronic elastic and total cross sections have become crucial instruments to probe the so called soft part of QCD physics, where quarks and gluons are confined, and have led to test and refine Regge behavior and a number of diffractive models. As the c.m. energy increases, the total cross section also probes the transition into hard scattering describable with perturbative QCD, the so-called mini-jet region. Further tests are provided by cross section measurements of γ p, γ ^* p and γ ^* γ ^* for models based on vector meson dominance, scaling limits of virtual photons at high Q^2 and the BFKL formalism. Models interpolating from virtual to real photons are also tested.
Modelling study on production cross sections of {sup 111}In radioisotopes used in nuclear medicine
Energy Technology Data Exchange (ETDEWEB)
Kara, Ayhan; Korkut, Turgay [Sinop Univ. (Turkey). Faculty of Engineering; Yigit, Mustafa [Aksaray Univ. (Turkey). Faculty of Science and Arts; Tel, Eyyup [Osmaniye Korkut Ata Univ. (Turkey). Faculty of Science and Arts
2015-07-15
Radiopharmaceuticals are radioactive drugs used for diagnosis or treatment in a tracer quantity with no pharmacological action. The production of radiopharmaceuticals is carried out in the special research centers generally using by the cyclotron systems. Indium-111 is one of the most useful radioisotopes used in nuclear medicine. In this paper, we calculated the production cross sections of {sup 111}In radioisotope via {sup 111-114}Cd(p,xn) nuclear reactions up to 60 MeV energy. In the model calculations, ALICE/ASH, TALYS 1.6 and EMPIRE 3.2 Malta nuclear reaction code systems were used. The model calculation results were compared to the experimental literature data and TENDL-2014 (TALYS-based) data.
Statistical Model Analysis of (n, α Cross Sections for 4.0-6.5 MeV Neutrons
Directory of Open Access Journals (Sweden)
Khuukhenkhuu G.
2016-01-01
Full Text Available The statistical model based on the Weisskopf-Ewing theory and constant nuclear temperature approximation is used for systematical analysis of the 4.0-6.5 MeV neutron induced (n, α reaction cross sections. The α-clusterization effect was considered in the (n, α cross sections. A certain dependence of the (n, α cross sections on the relative neutron excess parameter of the target nuclei was observed. The systematic regularity of the (n, α cross sections behaviour is useful to estimate the same reaction cross sections for unstable isotopes. The results of our analysis can be used for nuclear astrophysical calculations such as helium burning and possible branching in the s-process.
Introduction to the physics of the total cross-section at LHC: A Review of Data and Models
Pancheri, Giulia
2016-01-01
This review describes the development of the physics of hadronic cross sections up to recent LHC results and cosmic ray experiments. We present here a comprehensive review - written with a historical perspective - about total cross-sections from medium to the highest energies explored experimentally and studied through a variety of methods and theoretical models for over sixty years. We begin by recalling the analytic properties of the elastic amplitude and the theorems about the asymptotic behavior of the total cross-section. A discussion of how proton-proton cross-sections are extracted from cosmic rays at higher than accelerator energies and help the study of these asymptotic limits, is presented. This is followed by a description of the advent of particle colliders, through which high energies and unmatched experimental precisions have been attained. Thus the measured hadronic elastic and total cross-sections have become crucial instruments to probe the so called soft part of QCD physics, where quarks and...
Accurate estimation of energy expenditure (EE) in children and adolescents is required for a better understanding of physiological, behavioral, and environmental factors affecting energy balance. Cross-sectional time series (CSTS) models, which account for correlation structure of repeated observati...
Total Cross Sections at current/Future Colliders, conventional models and QCD
Fazal-e-Aleem, M
1999-01-01
Rise in total cross sections for elastic scattering generated immense interest both for experimental measurements and theoretical investigations. How will total cross section behave at LHC and Cosmic Ray energies is therefore in the limelight of our future measurements. Theoretical studies become even more interesting when we take into consideration the ratio of real and imaginary parts of the scattering amplitudes. We will briefly undertake the current results and future prospects in the light of conventional as well as QCD-based phenomenology.
Study of the neon interaction cross section using the Glauber model
Energy Technology Data Exchange (ETDEWEB)
Ahmad, Suhel; Usmani, A.A.; Khan, Z.A. [Aligarh Muslim University, Department of Physics, Aligarh (India); Chauhan, Deeksha [United College of Engineering and Research, Naini, Allahabad (India)
2016-05-15
Working within the framework of the Coulomb-modified correlation expansion for the Glauber model S-matrix, we calculate the interaction cross section (σ{sub I}) of neon isotopes, {sup 17-32}Ne, on {sup 12}C at 240 MeV/nucleon. The calculations involve i) up to the two-body density term in the correlation expansion, and ii) the single Gaussian approximation for the nucleon-nucleon amplitude. The colliding nuclei are described with Slater determinants consisting of the harmonic oscillator single-particle wave functions. The sole input of the density of each colliding nucleus, the oscillator constant, is fixed from the respective root-mean-square (rms) radius calculated using the relativistic mean-field approach. It is found that the calculated results for σ{sub I} generally provide fairly good agreement with the experimental data except for {sup 31}Ne, for which the required rms neutron radius comes closer to the one obtained earlier using the extended (halo-like) neutron density distribution. This finding is also supported by our predicted differential cross section of {sup 31}Ne on {sup 12}C at 240 MeV/nucleon. However, as expected, the results of the present analysis are unable to discriminate between the halo and non-halo structure of {sup 31}Ne. In conclusion, our results suggest that the present calculations can be considered as a good starting point to predict the rms matter radii of exotic neutron-rich nuclei. (orig.)
DeMaris, Alfred
2014-09-01
Unmeasured confounding is the principal threat to unbiased estimation of treatment "effects" (i.e., regression parameters for binary regressors) in nonexperimental research. It refers to unmeasured characteristics of individuals that lead them both to be in a particular "treatment" category and to register higher or lower values than others on a response variable. In this article, I introduce readers to 2 econometric techniques designed to control the problem, with a particular emphasis on the Heckman selection model (HSM). Both techniques can be used with only cross-sectional data. Using a Monte Carlo experiment, I compare the performance of instrumental-variable regression (IVR) and HSM to that of ordinary least squares (OLS) under conditions with treatment and unmeasured confounding both present and absent. I find HSM generally to outperform IVR with respect to mean-square-error of treatment estimates, as well as power for detecting either a treatment effect or unobserved confounding. However, both HSM and IVR require a large sample to be fully effective. The use of HSM and IVR in tandem with OLS to untangle unobserved confounding bias in cross-sectional data is further demonstrated with an empirical application. Using data from the 2006-2010 General Social Survey (National Opinion Research Center, 2014), I examine the association between being married and subjective well-being.
Microscopic cross sections: An utopia?
Energy Technology Data Exchange (ETDEWEB)
Hilaire, S. [CEA Bruyeres-le-Chatel, DIF 91 (France); Koning, A.J. [Nuclear Research and Consultancy Group, PO Box 25, 1755 ZG Petten (Netherlands); Goriely, S. [Institut d' Astronomie et d' Astrophysique, Universite Libre de Bruxelles, Campus de la Plaine, CP 226, 1050 Brussels (Belgium)
2010-07-01
The increasing need for cross sections far from the valley of stability poses a challenge for nuclear reaction models. So far, predictions of cross sections have relied on more or less phenomenological approaches, depending on parameters adjusted to available experimental data or deduced from systematical relations. While such predictions are expected to be reliable for nuclei not too far from the experimentally known regions, it is clearly preferable to use more fundamental approaches, based on sound physical bases, when dealing with very exotic nuclei. Thanks to the high computer power available today, all major ingredients required to model a nuclear reaction can now be (and have been) microscopically (or semi-microscopically) determined starting from the information provided by a nucleon-nucleon effective interaction. We have implemented all these microscopic ingredients in the TALYS nuclear reaction code, and we are now almost able to perform fully microscopic cross section calculations. The quality of these ingredients and the impact of using them instead of the usually adopted phenomenological parameters will be discussed. (authors)
Total Reaction Cross Section in an Isospin-Dependent Quantum Molecular Dynamics Model
Institute of Scientific and Technical Information of China (English)
魏义彬; 蔡翔舟; 沈文庆; 马余刚; 张虎勇; 钟晨; 郭威; 陈金根; 马国亮; 王鲲
2003-01-01
The isospin-dependent quantum molecular dynamics (IDQMD) model is used to study the total reaction cross section σR. The energy-dependent Pauli volumes of neutrons and protons have been discussed and introduced into the IDQMD calculation to replace the widely used energy-independent Pauli volumes. The modified IDQMD calculation can reproduce the experimental cr R well for both stable and exotic nuclei induced reactions. Comparisons of the calculated σn induced by 11Li with different initial density distributions have been performed. It is shown that the calculation by using the experimentally deduced density distribution with a long tail can fit the experimental excitation function better than that by using the Skyrme-Hartree-Fock calculated density without long tails. It is also found that σR at high energy is sensitive to the long tail of density distribution.
Directory of Open Access Journals (Sweden)
R. Wagner
2011-09-01
Full Text Available We present computational results on the shape dependency of the extinction and absorption cross sections of dustlike aerosol particles that were modeled as randomly oriented spheroids. Shape dependent variations in the extinction cross sections are largest in the size regime that is governed by the interference structure. Elongated spheroids best fitted measured extinction spectra of re-dispersed Saharan dust samples. For dust particles smaller than 1.5 μm in diameter and low absorption potential, shape effects on the absorption cross sections are very small.
Köhn, C.; Ebert, U.
2012-01-01
We model the energy resolved angular distribution of TGFs and of positrons produced by a negative lightning leader stepping upwards in a thundercloud. First we present our new results for doubly differential cross sections for Bremsstrahlung and pair production based on the triply differential cross
Yalcin, C; Rauscher, T; Kiss, G G; Özkan, N; Güray, R T; Halász, Z; Szücs, T; Fülöp, Zs; Korkulu, Z; Somorjai, E
2015-01-01
Astrophysical reaction rates, which are mostly derived from theoretical cross sections, are necessary input to nuclear reaction network simulations for studying the origin of $p$ nuclei. Past experiments have found a considerable difference between theoretical and experimental cross sections in some cases, especially for ($\\alpha$,$\\gamma$) reactions at low energy. Therefore, it is important to experimentally test theoretical cross section predictions at low, astrophysically relevant energies. The aim is to measure reaction cross sections of $^{107}$Ag($\\alpha$,$\\gamma$)$^{111}$In and $^{107}$Ag($\\alpha$,n)$^{110}$In at low energies in order to extend the experimental database for astrophysical reactions involving $\\alpha$ particles towards lower mass numbers. Reaction rate predictions are very sensitive to the optical model parameters and this introduces a large uncertainty into theoretical rates involving $\\alpha$ particles at low energy. We have also used Hauser-Feshbach statistical model calculations to s...
Feirstine, K.; Bush, K.; Crosher, C.; Klein, M.; Bowers, D.; Wellems, D.; Duggin, M.; Vaughn, L.
2012-09-01
The Air Force Research Laboratory (AFRL) Time-domain Analysis Simulation for Advanced Tracking (TASAT) was used to explore the variation of Optical Cross Section (OCS) with glint angle for a solar panel with different solar cell attitude distribution statistics. Simulations were conducted using a 3D model of a solar panel with various solar cell tip and tilt distribution statistics. Modeling a solar panel as a single sheet of "solar cell" material is not appropriate for OCS glint studies. However, modeling each individual solar cell on the panel, the tips and tilts of which come from a distribution of specified statistics (distribution type, mean, and standard deviation), accurately captures the solar panel OCS with glint angle. The objective of the simulations was to vary the glint measurement angle about the maximum glint position of the solar panel and observe the variations in OCS with angle for a bi-static illumination condition. OCS was calculated relative to the simulated scattering of a Spectralon material in the glint orientation. Results show the importance of solar cell attitude distribution statistics in modeling the OCS observed for a solar panel.
Energy Technology Data Exchange (ETDEWEB)
Georgieva, Emiliya Lyudmilova
2016-06-06
The novel academic contributions are summarized as follows. A) A cross-section modelling methodology and a cycle-specific cross-section update procedure are developed to meet fidelity requirements applicable to a cycle-specific reactor core simulation, as well as particular customer needs and practices supporting VVER-1000 operation and safety. B) A real-time version of the Nodal Expansion Method code is developed and implemented into Kozloduy 6 full-scope replica control room simulator.
Model inverse calculation of current distributions in the cross-section of a superconducting cable
Energy Technology Data Exchange (ETDEWEB)
Usak, P. [Institute of Electrical Engineering, Department of Electrodynamics of Superconductors, Slovak Academy of Sciences, Bratislava (Slovakia)]. E-mail: elekusak@savba.sk; Sastry, P.V.P.S.S. [Center for Advanced Power Systems, Florida State University, Tallahassee, FL 32310 (United States); Schwartz, J. [Center for Advanced Power Systems, Florida State University, Tallahassee, FL 32310 (United States); National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Department of Mechanical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL 32310 (United States)
2006-02-01
The solution of an inverse problem for magnetic field mapping, and the related current distribution in the cross-section of a superconducting cable are generally not unique. Nevertheless, for many natural configurations of a transport current distribution in the cross-section of a superconducting cable, the resulting magnetic field can be used for the reconstruction of a current distribution even in the presence of noise to a degree. We show it using several examples. To perform the inverse calculation, the Tichonov method of regularization was successfully applied. The approach was applied for superconducting cables, but its application is general.
Ground truth methods for optical cross-section modeling of biological aerosols
Kalter, J.; Thrush, E.; Santarpia, J.; Chaudhry, Z.; Gilberry, J.; Brown, D. M.; Brown, A.; Carter, C. C.
2011-05-01
Light detection and ranging (LIDAR) systems have demonstrated some capability to meet the needs of a fastresponse standoff biological detection method for simulants in open air conditions. These systems are designed to exploit various cloud signatures, such as differential elastic backscatter, fluorescence, and depolarization in order to detect biological warfare agents (BWAs). However, because the release of BWAs in open air is forbidden, methods must be developed to predict candidate system performance against real agents. In support of such efforts, the Johns Hopkins University Applied Physics Lab (JHU/APL) has developed a modeling approach to predict the optical properties of agent materials from relatively simple, Biosafety Level 3-compatible bench top measurements. JHU/APL has fielded new ground truth instruments (in addition to standard particle sizers, such as the Aerodynamic particle sizer (APS) or GRIMM aerosol monitor (GRIMM)) to more thoroughly characterize the simulant aerosols released in recent field tests at Dugway Proving Ground (DPG). These instruments include the Scanning Mobility Particle Sizer (SMPS), the Ultraviolet Aerodynamic Particle Sizer (UVAPS), and the Aspect Aerosol Size and Shape Analyser (Aspect). The SMPS was employed as a means of measuring smallparticle concentrations for more accurate Mie scattering simulations; the UVAPS, which measures size-resolved fluorescence intensity, was employed as a path toward fluorescence cross section modeling; and the Aspect, which measures particle shape, was employed as a path towards depolarization modeling.
Energy Technology Data Exchange (ETDEWEB)
Matsuoka, T.; Tamagawa, T. [Japan Petroleum Exploration Corp., Tokyo (Japan); Tsukui, R. [Japan National Oil Corp., Tokyo (Japan). Technology Research Center
1997-05-27
Pre-stacking depth migration treatment is studied for the estimation of the fold configuration from seismic survey cross sections. The estimation of a velocity structure is necessary for the execution of such treatment, and the utilization of structural-geological knowledge is required for its interpretation. The concept of balanced cross section in relation to the fault-bend fold constructs a stratum structure model under conditions that the deformation during fold and fault formation is a planar strain, that there is no change in volume due to deformation, and that a fold is a parallel fold. In addition to the above geometric and kinetic approach, there is another fold formation process simulation model using a Newtonian fluid for study from the viewpoint of dynamics. This simulation stands on the presumption that the boundary contains a ramp that had been in presence before fold formation and that an incompressible viscous matter is mounted on the top surface. The viscous matter flows and deforms for the formation of an anticline on the ramp. Such enables the reproduction of a fault-bend fold formation process, and helpful discussion may be furthered on the dynamic aspect of this simulation. 5 refs., 4 figs.
The effect of scaling physiological cross-sectional area on musculoskeletal model predictions.
Bolsterlee, Bart; Vardy, Alistair N; van der Helm, Frans C T; Veeger, H E J DirkJan
2015-07-16
Personalisation of model parameters is likely to improve biomechanical model predictions and could allow models to be used for subject- or patient-specific applications. This study evaluates the effect of personalising physiological cross-sectional areas (PCSA) in a large-scale musculoskeletal model of the upper extremity. Muscle volumes obtained from MRI were used to scale PCSAs of five subjects, for whom the maximum forces they could exert in six different directions on a handle held by the hand were also recorded. The effect of PCSA scaling was evaluated by calculating the lowest maximum muscle stress (σmax, a constant for human skeletal muscle) required by the model to reproduce these forces. When the original cadaver-based PCSA-values were used, strongly different between-subject σmax-values were found (σmax=106.1±39.9 N cm(-2)). A relatively simple, uniform scaling routine reduced this variation substantially (σmax=69.4±9.4 N cm(-2)) and led to similar results to when a more detailed, muscle-specific scaling routine was used (σmax=71.2±10.8 N cm(-2)). Using subject-specific PCSA values to simulate an shoulder abduction task changed muscle force predictions for the subscapularis and the pectoralis major on average by 33% and 21%, respectively, but was force changed less than 1.5% as a result of scaling. We conclude that individualisation of the model's strength can most easily be done by scaling PCSA with a single factor that can be derived from muscle volume data or, alternatively, from maximum force measurements. However, since PCSA scaling only marginally changed muscle and joint contact force predictions for submaximal tasks, the need for PCSA scaling remains debatable. Copyright © 2015 Elsevier Ltd. All rights reserved.
XCOM: Photon Cross Sections Database
SRD 8 XCOM: Photon Cross Sections Database (Web, free access) A web database is provided which can be used to calculate photon cross sections for scattering, photoelectric absorption and pair production, as well as total attenuation coefficients, for any element, compound or mixture (Z <= 100) at energies from 1 keV to 100 GeV.
Energy Technology Data Exchange (ETDEWEB)
Vogt, R
2007-09-14
We assess the theoretical uncertainties on the total charm cross section. We discuss the importance of the quark mass, the scale choice and the parton densities on the estimate of the uncertainty. We conclude that the uncertainty on the total charm cross section is difficult to quantify.
Coupling cavity model for circular cylindrical waveguide with uniform cross section
Ayzatsky, M I
2016-01-01
We developed the general approach that gives possibility to calculate the coupling coefficients for arbitrary chain of resonators without using the great number of eigen functions. For understanding this method and having possibility to control the accuracy of obtained results, we applied this procedure for simplest structure that has the analytical solutions - a circular cylindrical waveguide with uniform cross section.
1973-12-01
cm2) (Refs. 7 and 9) (9Cross-Section, a(10- 16 cm 2) First Second At ~ Atom or Fuchtbauer., Molecule Joos and Zemansky Kunze Din kelac ke r Hg He 15.0...G. and M. W. Zemansky , Resonance Radiation and ExcitedI4 Atoms, Cambridge, 1934. 10. Herzberg, G., Infrared and Raman Spectra, Van Nostrand, 1945. 11
Top pair cross section measurements (incl./diff.) and event modelling with the CMS detector
Keaveney, James Michael
2016-01-01
Precision measurements are presented of the top-quark pair inclusive production cross section in proton-proton collisions at the LHC at centre-of-mass energies of 7, 8 and 13 TeV. The data are collected with the CMS experiment during the years 2011, 2012, and 2015. The analyses profit from different top quark final states and make use of events with two, one or no reconstructed charged leptons. In most analyses b-jet identification is used to increase the purity of the selection. The backgrounds are determined using data-driven techniques. The results are combined with each other and compared with theory predictions. Indirect constraints on both the top quark mass and alpha_s are obtained through their relation to the inclusive cross section.Differential top quark pair production cross sections are measured in proton-proton collisions at the LHC at centre-of-mass energies of 7, 8, and 13 TeV, using data collected by the CMS experiment in the years 2011, 2012, and 2015. The differential cross sections are meas...
Energy Technology Data Exchange (ETDEWEB)
Tamagawa, T.; Matsuoka, T. [Japan Petroleum Exploration Corp., Tokyo (Japan); Tsukui, R. [Japan National Oil Corp., Tokyo (Japan). Technology Research Center
1997-05-27
It occasionally happens that there exists a part where reflection near the thrust is not clearly observed in a thrust zone seismic survey cross section. For the effective interpretation of such an occurrence, the use of geological structures as well as the reflected pattern is effective. When the velocity structures for a fold structure having a listric fault caused anticline (unidirectionally inclined with a backlimb, without a forelimb) and for a fault propagation fold are involved, a wrong interpretation may be made since they look alike in reflection wave pattern despite their difference in geological structure. In the concept of balanced cross section, a check is performed, when the stratum after deformation is recovered to the time of deposition, as to whether the geologic stratum area is conserved without excess or shortage. An excess or shortage occurs if there is an error in the model, and this shows that the fault surface or fold structure is not correctly reflected. Positive application of geological knowledge is required in the processing and interpreting of data from a seismic survey. 6 refs., 6 figs.
Titan's Modeled Thermospheric Composition Sensitivity to Solar Cycle and Cross Section Resolution
Luspay-Kuti, A.; Mandt, K.; Greathouse, T. K.; Plessis, S.
2015-12-01
Saturn's largest moon, Titan has been in the spotlight of planetary research for seven decades now. This unique satellite is the only other planetary body besides the Earth to possess a substantial N2 dominated atmosphere, and stable bodies of liquids on its surface. The atmosphere and the surface are strongly coupled, and the liquids on the surface are a consequence of chemistry in the atmosphere. Titan's dense atmosphere is the site of rich organic chemistry, which begins with the photolytic destruction of the two most abundant atmospheric constituents: N2 and CH4. Photochemical modeling is an important tool in understanding the details of higher-order hydrocarbon and nitrile formation and loss at various altitudes in Titan's atmosphere, which also affect the rate of deposition onto Titan's surface. However, significant discrepancies exist among modeled (and measured) atmospheric densities of minor species, which warrant the evaluation of influencing factors in photochemical modeling. Here, we address the role of the choice of N2 photoabsorption cross-section resolution and variations in solar flux with solar cycle on the vertical profiles of various minor species in Titan's thermosphere. Special attention is placed on the changes in production and loss rates of C2H6 and HCN in response to the varying model parameters. C2H6 is the most important sink for CH4, and is a major component of the surface hydrocarbon lakes. HCN production is the first step in the incorporation of nitrogen into tholins, and is relevant to potential amino acid formation. Furthermore, HCN is the main coolant in Titan's upper atmosphere. Thus, these two minor species are particularly important in the grand scheme of Titan's coupled surface-atmosphere system.
Fukuya, K
2003-01-01
The displacement cross-section of iron was calculated for gamma-ray irradiation with the energy range of 1 to 15 MeV, which corresponds to radiation fields in fission reactors. Three gamma-material interactions, Compton scattering, pair production and photoelectric effect were considered. The displacements induced by both electrons and positrons were included. For damage function the modified Kinchin-Pease model with the displacement energy of 40 eV was applied, which are used as the standard damage model in neutron-induced displacement calculations. The standard damage model gave a lower cross-section by a factor of 1.3 compared to Kinchin-Pease model, and the exact treatment of positron contribution gave a lower cross-section by a factor 1.1 compared to an approximation treating positrons as electrons. The present cross-section was lower by a factor of 1.1-2.0 than the cross-sections previously proposed in the literatures. (author)
Energy Technology Data Exchange (ETDEWEB)
1984-05-01
The term modeling in the Workship title refers to the mathematical analysis of the consequences of many collision processes for characterizing the physical stage of radiation actions. It requires as input some knowledge of collision cross sections. Traditionally, work on cross sections and work on the modeling are conducted by separate groups of scientists. It was the purpose of the Workshop to bring these two groups together in a forum that would promote effective communication. Cross-section workers described the status of their work and told what data were available or trustworthy. Modeling workers told what kind of data were needed or were most important. Twenty-two items from the workshop were prepared separately for the data base.
Energy Technology Data Exchange (ETDEWEB)
Xiao, Ye; Huang, Zaixing, E-mail: huangzx@nuaa.edu.cn [State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing (China)
2015-11-15
The equilibrium configuration equations of DNA chain with elastic rod model are derived in detail by the variation of the free energy functional, which depends on the curvature, torsion, twisting angle and its derivative with respect to the arc-length of central axis curve of rod. With the different shapes of rod, we obtain the equilibrium equations of DNA with circular and noncircular cross sections, which provide an approach to describe the physical behaviors of A-, B-, Z-DNA. The results show that the elastic rod model with circular cross section can accurately characterize the equilibrium configurations of A-, B-DNA, while the model with elliptical cross sections is more suitable for Z-DNA.
An evolutionary attractor model for sapwood cross section in relation to leaf area.
Westoby, Mark; Cornwell, William K; Falster, Daniel S
2012-06-21
Sapwood cross-sectional area per unit leaf area (SA:LA) is an influential trait that plants coordinate with physical environment and with other traits. We develop theory for SA:LA and also for root surface area per leaf area (RA:LA) on the premise that plants maximizing the surplus of revenue over costs should have competitive advantage. SA:LA is predicted to increase in water-relations environments that reduce photosynthetic revenue, including low soil water potential, high water vapor pressure deficit (VPD), and low atmospheric CO(2). Because sapwood has costs, SA:LA adjustment does not completely offset difficult water relations. Where sapwood costs are large, as in tall plants, optimal SA:LA may actually decline with (say) high VPD. Large soil-to-root resistance caps the benefits that can be obtained from increasing SA:LA. Where a plant can adjust water-absorbing surface area of root per leaf area (RA:LA) as well as SA:LA, optimal RA:SA is not affected by VPD, CO(2) or plant height. If selection favours increased height more so than increased revenue-minus-cost, then height is predicted to rise substantially under improved water-relations environments such as high-CO(2) atmospheres. Evolutionary-attractor theory for SA:LA and RA:LA complements models that take whole-plant conductivity per leaf area as a parameter. Copyright © 2012 Elsevier Ltd. All rights reserved.
Chumachenko, E. N.
2008-08-01
The necessity to develop and optimize new technological processes of gas moulding of shells under the superplasticity conditions, which ensure large elongation and complexity of the shape of end items, makes the specialists in the field of mathematical simulation to pose and solve problems of constant improvement of the imitation models. Because of a large number of "embedded" nonlinearities (the physical properties of the material, friction, and unknown boundaries), the solution of such problems requires large computer resources, high qualification of designers, and large amount of labor. In the present paper, we consider the problems of express analysis of pattern change of spatial shells on the basis of estimation of the behavior of their critical cross-sections. We solve problems of moulding of titan shells (made of VT6 alloy) in a matrix of complicated shape. We theoretically and experimentally justify the methods for predicting and constructing the optimal technological processes of shell deformation under conditions close to superplasticity by using the 2.5D designing procedures.
Nucleon-XcJ Dissociation Cross Sections
Institute of Scientific and Technical Information of China (English)
冯又层; 许晓明; 周代翠
2002-01-01
Nucleon-XcJ dissociation cross sections are calculated in a constituent interexchange model in which quark-quark potential is derived from the Buchmüller-Tye quark-anti-quark potential. These new cross sections for dominant reaction channels depend on the centre-of-mass energy of the nucleon and the charmonium.
Comparison of GEANT4 very low energy cross section models with experimental data in water
Energy Technology Data Exchange (ETDEWEB)
Incerti, S.; Ivanchenko, A.; Karamitros, M.; Mantero, A.; Moretto, P.; Tran, H. N.; Mascialino, B.; Champion, C.; Ivanchenko, V. N.; Bernal, M. A.; Francis, Z.; Villagrasa, C.; Baldacchino, G.; Gueye, P.; Capra, R.; Nieminen, P.; Zacharatou, C. [Universite Bordeaux 1, CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux-Gradignan, CENBG, Chemin du Solarium, BP 120, 33175 Gradignan (France); Karolinska Institutet, P.O. Box 260, S-171-76 Stockholm (Sweden); Laboratoire de Physique Moleculaire et des Collisions, Universite Paul Verlaine-Metz, 1 Boulevard Arago, Technopo circumflex le 2000, 57078 Metz (France); Departamento de Fisica, Universidad Simon Bolivar, P.O. Box 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); IRSN, Institut de Radioprotection et de Surete Nucleaire, BP17, 92262 Fontenay-aux-Roses (France); CEA Saclay, IRAMIS, UMR 3299 CEA-CNRS SIS2M, Laboratoire de Radiolyse, F-91191 Gif-sur-Yvette Cedex (France); Department of Physics, Hampton University, Hampton, Virginia 23668 (United States); Via Niella 12, 17100 Savona (Italy); ESA-ESTEC, 2200 AG Noordwijk (Netherlands); Niels Bohr Institute, Blegdamsvej 17, 2100 Copenhagen (Denmark)
2010-09-15
Purpose: The GEANT4 general-purpose Monte Carlo simulation toolkit is able to simulate physical interaction processes of electrons, hydrogen and helium atoms with charge states (H{sup 0}, H{sup +}) and (He{sup 0}, He{sup +}, He{sup 2+}), respectively, in liquid water, the main component of biological systems, down to the electron volt regime and the submicrometer scale, providing GEANT4 users with the so-called ''GEANT4-DNA'' physics models suitable for microdosimetry simulation applications. The corresponding software has been recently re-engineered in order to provide GEANT4 users with a coherent and unique approach to the simulation of electromagnetic interactions within the GEANT4 toolkit framework (since GEANT4 version 9.3 beta). This work presents a quantitative comparison of these physics models with a collection of experimental data in water collected from the literature. Methods: An evaluation of the closeness between the total and differential cross section models available in the GEANT4 toolkit for microdosimetry and experimental reference data is performed using a dedicated statistical toolkit that includes the Kolmogorov-Smirnov statistical test. The authors used experimental data acquired in water vapor as direct measurements in the liquid phase are not yet available in the literature. Comparisons with several recommendations are also presented. Results: The authors have assessed the compatibility of experimental data with GEANT4 microdosimetry models by means of quantitative methods. The results show that microdosimetric measurements in liquid water are necessary to assess quantitatively the validity of the software implementation for the liquid water phase. Nevertheless, a comparison with existing experimental data in water vapor provides a qualitative appreciation of the plausibility of the simulation models. The existing reference data themselves should undergo a critical interpretation and selection, as some of the series
Directory of Open Access Journals (Sweden)
Hogg William
2011-10-01
Full Text Available Abstract Background Primary care providers play an important role in preventing and managing cardiovascular disease. This study compared the quality of preventive cardiovascular care delivery amongst different primary care models. Methods This is a secondary analysis of a larger randomized control trial, known as the Improved Delivery of Cardiovascular Care (IDOCC through Outreach Facilitation. Using baseline data collected through IDOCC, we conducted a cross-sectional study of 82 primary care practices from three delivery models in Eastern Ontario, Canada: 43 fee-for-service, 27 blended-capitation and 12 community health centres with salary-based physicians. Medical chart audits from 4,808 patients with or at high risk of developing cardiovascular disease were used to examine each practice's adherence to ten evidence-based processes of care for diabetes, chronic kidney disease, dyslipidemia, hypertension, weight management, and smoking cessation care. Generalized estimating equation models adjusting for age, sex, rurality, number of cardiovascular-related comorbidities, and year of data collection were used to compare guideline adherence amongst the three models. Results The percentage of patients with diabetes that received two hemoglobin A1c tests during the study year was significantly higher in community health centres (69% than in fee-for-service (45% practices (Adjusted Odds Ratio (AOR = 2.4 [95% CI 1.4-4.2], p = 0.001. Blended capitation practices had a significantly higher percentage of patients who had their waistlines monitored than in fee-for-service practices (19% vs. 5%, AOR = 3.7 [1.8-7.8], p = 0.0006, and who were recommended a smoking cessation drug when compared to community health centres (33% vs. 16%, AOR = 2.4 [1.3-4.6], p = 0.007. Overall, quality of diabetes care was higher in community health centres, while smoking cessation care and weight management was higher in the blended-capitation models. Fee-for-service practices
Nobre, G P A; Escher, J E; Thompson, I J; Dupuis, M; Terasaki, J; Engel, J
2010-01-01
A microscopic calculation of the reaction cross-section for nucleon-nucleus scattering has been performed by explicitly coupling the elastic channel to all particle-hole (p-h) excitation states in the target and to all one-nucleon pickup channels. The p-h states may be regarded as doorway states through which the flux flows to more complicated configurations, and subsequently to long-lived compound nucleus resonances. Target excitations for 40,48Ca, 58Ni, 90Zr and 144Sm were described in a QRPA framework using a Skyrme functional. Reaction cross sections calculated in this approach were compared to predictions of a fitted optical potential and to experimental data, reaching very good agreement. Couplings between inelastic states were found to be negligible, while the couplings to pickup channels contribute significantly. For the first time observed reaction cross-sections are completely accounted for by explicit channel coupling, for incident energies between 10 and 40 MeV.
A simple method to approximate liver size on cross-sectional images using living liver models
Energy Technology Data Exchange (ETDEWEB)
Muggli, D.; Mueller, M.A.; Karlo, C.; Fornaro, J.; Marincek, B. [Institute of Diagnostic Radiology, University Hospital of Zurich, Zurich (Switzerland); Frauenfelder, T. [Institute of Diagnostic Radiology, University Hospital of Zurich, Zurich (Switzerland)], E-mail: thomas.frauenfelder@usz.ch
2009-07-15
Aim: To assess whether a simple. diameter-based formula applicable to cross-sectional images can be used to calculate the total liver volume. Materials and methods: On 119 cross-sectional examinations (62 computed tomography and 57 magnetic resonance imaging) a simple, formula-based method to approximate the liver volume was evaluated. The total liver volume was approximated measuring the largest craniocaudal (cc), ventrodorsal (vd), and coronal (cor) diameters by two readers and implementing the equation: Vol{sub estimated}=ccxvdxcorx0.31. Inter-rater reliability, agreement, and correlation between liver volume calculation and virtual liver volumetry were analysed. Results: No significant disagreement between the two readers was found. The formula correlated significantly with the volumetric data (r > 0.85, p < 0.0001). In 81% of cases the error of the approximated volume was <10% and in 92% of cases <15% compared to the volumetric data. Conclusion: Total liver volume can be accurately estimated on cross-sectional images using a simple, diameter-based equation.
Neutrino nucleus cross sections
Athar, M Sajjad; Singh, S K; Vacas, M J Vicente
2008-01-01
We present the results of our calculation which has been performed to study the nuclear effects in the quasielastic, inelastic and deep inelastic scattering of neutrinos(antineutrinos) from nuclear targets. These calculations are done in the local density approximation. We take into account the effect of Pauli blocking, Fermi motion, Coulomb effect, renormalization of weak transition strengths in the nuclear medium in the case of the quasielastic reaction. The inelastic reaction leading to production of pions is calculated in a $\\Delta $- dominance model taking into account the renormalization of $\\Delta$ properties in the nuclear medium and the final state interaction effects of the outgoing pions with the residual nucleus. We discuss the nuclear effects in the $F_{3}^{A}(x)$ structure function in the deep inelastic neutrino(antineutrino) reaction using a relativistic framework to describe the nucleon spectral function in the nucleus.
Sharf, I V; Sokhrannyi, G O; Yatkin, K V; Rusov, V D
2009-01-01
The method for taking into account the interference contributions to hadron inelastic scattering cross-section is developed within the framework of the simplest multiperipheral model. This method is based on the self-acting scalar fi^3 field theory and the Laplace method using. It was shown that the considered in [1] mechanism of virtuality diminishing at the energy sqrt(s) growth with consideration of all considerable interference contributions into account can be responsible for the total hadron scattering cross-section growth which is experimentally observed. The offered model reproduces well at qualitative level the experimental dependence of total scattering cross-section on energy sqrt(s) with a characteristic minimum in the range sqrt(s) around 10 GeV.
Energy Technology Data Exchange (ETDEWEB)
Chiba, Satoshi; Iwamoto, Osamu; Fukahori, Tokio; Niita, Koji; Maruyama, Toshiki; Maruyama, Tomoyuki; Iwamoto, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1997-03-01
The production cross sections of various fragments from proton-induced reactions on {sup 56}Fe and {sup 27}Al have been analyzed by the Quantum Molecular Dynamics (QMD) plus Statistical Decay Model (SDM). It was found that the mass and charge distributions calculated with and without the statistical decay have very different shapes. These results also depend strongly on the impact parameter, showing an importance of the dynamical treatment as realized by the QMD approach. The calculated results were compared with experimental data in the energy region from 50 MeV to 5 GeV. The QMD+SDM calculation could reproduce the production cross sections of the light clusters and intermediate-mass to heavy fragments in a good accuracy. The production cross section of {sup 7}Be was, however, underpredicted by approximately 2 orders of magnitude, showing the necessity of another reaction mechanism not taken into account in the present model. (author)
Modeling of cognitive impairment by disease duration in multiple sclerosis: a cross-sectional study.
Directory of Open Access Journals (Sweden)
Anat Achiron
Full Text Available BACKGROUND/AIMS: Large-scale population studies measuring rates and dynamics of cognitive decline in multiple sclerosis (MS are lacking. In the current cross-sectional study we evaluated the patterns of cognitive impairment in MS patients with disease duration of up to 30 years. METHODS: 1,500 patients with MS were assessed by a computerized cognitive battery measuring verbal and non-verbal memory, executive function, visual spatial perception, verbal function, attention, information processing speed and motor skills. Cognitive impairment was defined as below one standard deviation (SD and severe cognitive impairment as below 2SD for age and education matched healthy population norms. RESULTS: Cognitive performance in our cohort was poorer than healthy population norms. The most frequently impaired domains were information processing speed and executive function. MS patients with secondary-progressive disease course performed poorly compared with clinically isolated syndrome, relapsing-remitting and primary progressive MS patients. By the fifth year from disease onset, 20.9% of patients performed below the 1SD cutoff for impairment, p=0.005, and 6.0% performed below the 2SD cutoff for severe cognitive impairment, p=0.002. By 10 years from onset 29.3% and 9.0% of patients performed below the 1SD and 2SD cutoffs, respectively, p=0.0001. Regression modeling suggested that cognitive impairment may precede MS onset by 1.2 years. CONCLUSIONS: The rates of cognitive impairment in this large sample of MS patients were lower than previously reported and severe cognitive impairment was evident only in a relatively small group of patients. Cognitive impairment differed significantly from expected normal distribution only at five years from onset, suggesting the existence of a therapeutic window during which patients may benefit from interventions to maintain cognitive health.
Fong, Duncan K. H.; Ebbes, Peter; DeSarbo, Wayne S.
2012-01-01
Multiple regression is frequently used across the various social sciences to analyze cross-sectional data. However, it can often times be challenging to justify the assumption of common regression coefficients across all respondents. This manuscript presents a heterogeneous Bayesian regression model that enables the estimation of…
Neal, J. C.; Odini, Nicolas; trigg, mark; Freer, Jim; garcia-pintado, javier; mason, david; Wood, Melissa; Bates, P. D.
2015-01-01
This paper investigates the challenge of representing structural differences in river channel cross-section geometry for regional to global scale river hydraulic models and the effect this can have on simulations of wave dynamics. Classically, channel geometry is defined using data, yet at larger
Directory of Open Access Journals (Sweden)
Yongzhao Wang
2015-01-01
Full Text Available The mechanical deformation of DNA is very important in many biological processes. In this paper, we consider the reduced Kirchhoff equations of the noncircular cross-section elastic rod characterized by the inequality of the bending rigidities. One family of exact solutions is obtained in terms of rational expressions for classical Jacobi elliptic functions. The present solutions allow the investigation of the dynamical behavior of the system in response to changes in physical parameters that concern asymmetry. The effects of the factor on the DNA conformation are discussed. A qualitative analysis is also conducted to provide valuable insight into the topological configuration of DNA segments.
Using MiniBooNE NCEL and CCQE cross section results to constrain 3+1 sterile neutrino models
Wilkinson, Callum; Thompson, Lee
2014-01-01
The MiniBooNE NCEL and CCQE cross-section measurements (neutrino running) are used to set limits in the $\\Delta m^{2}-\\sin^{2}\\vartheta_{\\mu s}$ plane for a 3+1 sterile neutrino model with a mass splitting $0.1 \\leq \\Delta m^{2} \\leq 10.0$ eV$^{2}$. GENIE is used, with a relativistic Fermi gas model, to relate $E_{\
Barghouty, A. F.
2013-01-01
Accurate estimates of electron-capture cross sections at energies relevant to ENA modeling (approx. few MeV per nucleon) and for multi-electron ions must rely on detailed, but computationally expensive, quantummechanical description of the collision process. Kuang's semi-classical approach is an elegant and efficient way to arrive at these estimates. Motivated by ENA modeling efforts, we shall briefly present this approach along with sample applications and report on current progress.
Watkins, Hannah; Butler, Robert W. H.; Bond, Clare E.
2017-03-01
We investigate changes in shortening, displacement and fold geometry to understand the detailed along-strike structural variation within fold-thrust belts, and infer thrust growth and linkage mechanisms. Field observations from the Vercors in SE France are used to characterise deformation style in the region. Parallel cross sections are constructed, analysed and used to create shortening and thrust displacement profiles from the northern to southern Vercors. Sections show changes in structural style and shortening accommodation from thrust-dominated in the north to fold-dominated in the south. The total shortening distance in the Vercors does not change significantly along strike (3400-4650 m), however displacements along individual thrust zones do vary significantly and displacement profiles show a range in displacement gradients (16-107 m/km). Despite relatively simple shortening patterns in the Vercors, sections show a more complex 3D internal structure of the fold-thrust belt. Thrust displacements and geometries suggest both large-scale thrust zones and small-scale thrusts are soft linked, transferring displacement along strike through transfer zones. Short, soft-linked thrust segments indicate an intermediate stage of thrust growth and linkage, well documented for normal fault systems, which form prior to the formation of thrust branches and hard-linked displacement transfer.
Stark, Glenn; Smith, P. L.; Lewis, B. R.; Heays, A. N.; Blackie, D.; Pickering, J.
2010-10-01
Our research program comprises the measurement and modeling of ultraviolet molecular photoabsorption cross sections with the highest practical resolution. Measurement and modeling efforts on molecular nitrogen, sulfur dioxide, diatomic sulfur, and carbon dioxide are in progress. N2: We measure line f-values and widths within the complex spectrum between 80 and 100 nm. Our measurements are incorporated into a theoretical model of the absorption spectrum of N2 which has established the mechanisms responsible for predissociation and reproduces the observed features in all N2 isotopomers as a function of temperature. SO2: We provide astronomers with high-resolution cross section data for the complex ultraviolet SO2 absorption spectrum. Using the Imperial College VUV Fourier transform spectrometer, we have completed and published cross sections from 198 to 325 nm (295 K) and from 199 to 220 nm (160 K). We have completed work on further low-temperature measurements from 220 to 325 nm. S2: Interpretations of atmospheric (Io, Jupiter) S2 absorption features are hindered by a complete lack of laboratory cross sections in the ultraviolet. We have begun to quantify the photoabsorption spectrum of S2 from 200 to 300 nm. We have designed an experimental apparatus to produce a stable column of S2 vapor. Measurements of S2 absorption features at high resolution will be complemented by coupled-channel calculations of the relevant transitions. CO2: The photodissociation of CO2 is a fundamental photochemical process in the atmospheres of Mars and Venus. Our research centers on the measurement of high resolution cross sections from 87 to 120 nm. We have completed measurements at 295 K and 195 K over the 106 to 120 nm region. We have recently completed preliminary room temperature measurements in the 87 to 106 nm region. We acknowledge grant support from NASA (NNX08AE78G), STFC-PPARC, and ARC (DP0558962).
Energy Technology Data Exchange (ETDEWEB)
Marcinkowski, A. (Ohio Univ., Athens, OH (United States) and Soltan Inst. for Nuclear Study, Warsaw (Poland)); Rapaport, J. (Ohio Univ., Athens, OH (United States)); Finlay, R.W. (Ohio Univ., Athens, OH (United States)); Brient, C. (Ohio Univ., Athens, OH (United States)); Herman, M. (ENEA-C.R.E. ' Clementel' , Bologna (Italy)); Chadwick, M.B. (Lawrence Livermore National Lab., Livermore, CA (United States))
1993-08-30
Inelastic neutron emission at 6.7 and 20 MeV incident energies has been measured for monoisotopic samples of [sup 165]Ho and [sup 181]Ta. Time-of-flight spectra were taken at several angles between 15 and 145 using a beam-swinger spectrometer. The cross sections are averaged over 1 MeV energy bins. The 20 MeV data, when compared with the quantum-mechanical statistical multistep calculations have revealed a magnitude problem in the existing theories. A gradual or 'multistep' absorption in the entrance channels is proposed as a way out of the difficulty. This modification turns out to be sufficient for an adequate description of the experimental data. (orig.)
Numerical model for surge and swab pressures on wells with cross-section variation
Energy Technology Data Exchange (ETDEWEB)
Fedevjcyk, Joao Victor; Junqueira, Silvio Luiz de Mello; Negrao, Cezar Otaviano Ribeiro [UTFPR - Federal University of Technology - Parana - Curitiba, PR (Brazil)], e-mails: silvio@utfpr.edu.br, negrao@utfpr.edu.br
2010-07-01
Drilling is one of the most complex steps in petroleum exploration. The process is accomplished by rotating a drill bit to compress the rock formation. During drilling, a fluid is pumped into the well to lubricate and cool down the drill bit, to clean up the well, to avoid the formation fluid influx to the well and also to stabilize the borehole walls. Fluid circulation, however, can be interrupted for maintenance reasons and the drill pipe can be moved to remove the drill bit. The downward or upward movement of the drill pipe displaces the fluid within the well causing either under pressure (swab) or over pressure (surge), respectively. If the pressure at the well bore overcomes the formation fracture pressure, a loss of circulation can take place. On the other way round, the upward movement may reduce the pressure below the pore pressure and an inflow of fluid to the well (kick) can occur. An uncontrolled kick may cause a blowout with serious damages. The transient flow induced by the axial movement of the drill pipe is responsible for the pressure changes at the well bore. Nevertheless, the well bore cross section variation may modify the pressure change within the pipe. In this paper, the effects of diameter variation of the drilling well on the surge and swab pressures are investigated. The equations that represent the phenomenon (mass and momentum conservation) are discretized by the finite volume method. Despite its non-Newtonian properties, the fluid is considered Newtonian in this first work. The drill pipe is considered closed and the flow is assumed as single-phased, one-dimensional, isothermal, laminar, compressible and transient. A sensitivity analysis of the flow parameters is carried out. The cross-section changes cause the reflection of the pressure wave, and consequently pressure oscillations. (author)
Revolutionizing Cross-sectional Imaging
Fan, Yifang; Luo, Liangping; Lin, Wentao; Li, Zhiyu; Zhong, Xin; Shi, Changzheng; Newman, Tony; Zhou, Yi; Lv, Changsheng; Fan, Yuzhou
2014-01-01
Cross-sectional imaging is so important that, six Nobel Prizes have been awarded to the field of nuclear magnetic resonance alone because it revolutionized clinical diagnosis. The BigBrain project supported by up to 1 billion euro each over a time period of 10 years predicts to "revolutionize our ability to understand internal brain organization" (Evan 2013). If we claim that cross-sectional imaging diagnosis is only semi-quantitative, some may believe because no doctor would ever tell their patient that we can observe the changes of this cross-sectional image next time. If we claim that BigBrain will make no difference in clinical medicine, then few would believe because no doctor would ever tell their patient to scan this part of the image and compare it with that from the BigBrain. If we claim that the BigBrain Project and the Human Brain Project have defects in their key method, one might believe it. But this is true. The key lies in the reconstruction of any cross-sectional image along any axis. Using Ga...
Total Cross Sections for Neutron Scattering
Chinn, C. R.; Elster, Ch.; Thaler, R. M.; Weppner, S. P.
1994-01-01
Measurements of neutron total cross-sections are both extensive and extremely accurate. Although they place a strong constraint on theoretically constructed models, there are relatively few comparisons of predictions with experiment. The total cross-sections for neutron scattering from $^{16}$O and $^{40}$Ca are calculated as a function of energy from $50-700$~MeV laboratory energy with a microscopic first order optical potential derived within the framework of the Watson expansion. Although ...
Improved concept models for straight thin-walled columns with box cross section
Institute of Scientific and Technical Information of China (English)
Yu-cheng LIU
2008-01-01
This paper focuses on developing improved concept models for straight thin-walled box sectional columns which can better predict the peak crushing force that occurs during crashworthiness analyses.We develop a nonlinear translational spring based on previous research and apply such a spring element to build the enhanced concept models.The work presented in this article is developed on the basis of the publication of the author(Liu and Day,2006b)and has been applied in a crashworthiness design issue,which is presented by the author in another paper(Liu,2008).
Energy Technology Data Exchange (ETDEWEB)
Hoffman, R. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2013-09-06
We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron induced nuclear reaction cross sections for targets ranging from Terbium (Z = 65) to Rhenium (Z = 75). Of particular interest are the cross sections on Tm, Lu, and Ta including reactions on isomeric targets.
Viggiano, Albert A; Friedman, Jeffrey F; Shuman, Nicholas S; Miller, Thomas M; Schaffer, Linda C; Troe, Jürgen
2010-05-21
Thermal electron attachment to C(60) has been studied by relative rate measurements in a flowing afterglow Langmuir probe apparatus. The rate coefficients of the attachment k(1) are shown to be close to 10(-6) cm(3) s(-1) with a small negative temperature coefficient. These results supersede measurements from the 1990s which led to much smaller values of k(1) with a large positive temperature coefficient suggesting an activation barrier. Theoretical modeling of k(1) in terms of generalized Vogt-Wannier capture theory shows that k(1) now looks more consistent with measurements of absolute attachment cross sections sigma(at) than before. The comparison of capture theory and experimental rate or cross section data leads to empirical correction factors, accounting for "intramolecular vibrational relaxation" or "electron-phonon coupling," which reduce k(1) below the capture results and which, on a partial wave-selected level, decrease with increasing electron energy.
Energy Technology Data Exchange (ETDEWEB)
Divadeenam, M.; Ward, T.E. (Brookhaven National Lab., Upton, NY (United States)); Spergel, M.S.; Lakatos, S.; Manche, E.P. (York Coll., Jamaica, NY (United States))
1991-01-01
For the purposes of interpreting the abundances of various isotopes in meteorites or on lunar and planetary surfaces exposed to fragmentation by cosmic rays, Webber et al. recently reported the measured total elemental and isotopic cross sections with heavy ions as projectiles on H, He, and C targets with beam energies of 0.33 - 1.7 GeV/nucleon. We employ the INC model to predict the fragmentation of the heavy ions in a hydrogen target with the inverse reaction process: proton bombardment of a heavy-ion nucleus leading to spallation products. Charge-changing and mass-changing cross sections are calculated for proton bombardment of an {sup 56}Fe target with beam energies ranging from 0.33 to 1.88 GeV. Total Z-changing and A-changing cross sections in the energy range 0.6 to 1.88 GeV are in excellent agreement with the corresponding experimental data of Webber et al. and Westfall at al., while the agreement below 0.6 GeV proton energy is not as good. The general trend of the Z-changing cross sections are reproduced by the model calculations at each proton incident energy. The interaction of 200-MeV protons with synthetic Stony Meteorite samples was undertaken to explain radionuclide production in a cosmic-ray environment. The BNL Linac 200-MeV-proton beam was used to irradiate synthetic Stony Meteorites to simulate cosmic-ray exposures corresponding to 6.4 and 16.4 million years. Each irradiated sample was analyzed with the help of a high-resolution gamma-ray spectrometer for long-lived radioisotopes. The intranuclear cascade code HETC was employed to simulate the 200-MeV proton bombardment on the meteorite samples to predict the radionuclides {sup 7}Be, {sup 22}Na, {sup 46}Mn, and {sup 56}Co produced in the experimental investigation.
Energy Technology Data Exchange (ETDEWEB)
Divadeenam, M.; Ward, T.E. [Brookhaven National Lab., Upton, NY (United States); Spergel, M.S.; Lakatos, S.; Manche, E.P. [York Coll., Jamaica, NY (United States)
1991-12-31
For the purposes of interpreting the abundances of various isotopes in meteorites or on lunar and planetary surfaces exposed to fragmentation by cosmic rays, Webber et al. recently reported the measured total elemental and isotopic cross sections with heavy ions as projectiles on H, He, and C targets with beam energies of 0.33 - 1.7 GeV/nucleon. We employ the INC model to predict the fragmentation of the heavy ions in a hydrogen target with the inverse reaction process: proton bombardment of a heavy-ion nucleus leading to spallation products. Charge-changing and mass-changing cross sections are calculated for proton bombardment of an {sup 56}Fe target with beam energies ranging from 0.33 to 1.88 GeV. Total Z-changing and A-changing cross sections in the energy range 0.6 to 1.88 GeV are in excellent agreement with the corresponding experimental data of Webber et al. and Westfall at al., while the agreement below 0.6 GeV proton energy is not as good. The general trend of the Z-changing cross sections are reproduced by the model calculations at each proton incident energy. The interaction of 200-MeV protons with synthetic Stony Meteorite samples was undertaken to explain radionuclide production in a cosmic-ray environment. The BNL Linac 200-MeV-proton beam was used to irradiate synthetic Stony Meteorites to simulate cosmic-ray exposures corresponding to 6.4 and 16.4 million years. Each irradiated sample was analyzed with the help of a high-resolution gamma-ray spectrometer for long-lived radioisotopes. The intranuclear cascade code HETC was employed to simulate the 200-MeV proton bombardment on the meteorite samples to predict the radionuclides {sup 7}Be, {sup 22}Na, {sup 46}Mn, and {sup 56}Co produced in the experimental investigation.
Path forward for dosimetry cross sections
Energy Technology Data Exchange (ETDEWEB)
Griffin, P.J. [Sandia National Laboratories, Albuquerque, NM 87185-1146 (United States); Peters, C.D. [Sandia Staffing Alliance, Albuquerque, NM 87110 (United States)
2011-07-01
In the 1980's the dosimetry community embraced the need for a high fidelity quantification of uncertainty in nuclear data used for dosimetry applications. This led to the adoption of energy-dependent covariance matrices as the accepted manner of quantifying the uncertainty data. The trend for the dosimetry community to require high fidelity treatment of uncertainty estimates has continued to the current time where requirements on nuclear data are codified in standards such as ASTM E 1018. This paper surveys the current state of the dosimetry cross sections and investigates the quality of the current dosimetry cross section evaluations by examining calculated-to-experimental ratios in neutron benchmark fields. In recent years more nuclear-related technical areas are placing an emphasis on uncertainty quantification. With the availability of model-based cross sections and covariance matrices produced by nuclear data codes, some nuclear-related communities are considering the role these covariance matrices should play. While funding within the dosimetry community for cross section evaluations has been very meager, other areas, such as the solar-related astrophysics community and the US Nuclear Criticality Safety Program, have been supporting research in the area of neutron cross sections. The Cross Section Evaluation Working Group (CSEWG) is responsible for the creation and maintenance of the ENDF/B library which has been the mainstay for the reactor dosimetry community. Given the new trends in cross section evaluations, this paper explores the path forward for the US nuclear reactor dosimetry community and its use of the ENDF/B cross-sections. The major concern is maintenance of the sufficiency and accuracy of the uncertainty estimate when used for dosimetry applications. The two major areas of deficiency in the proposed ENDF/B approach are: 1) the use of unrelated covariance matrices in ENDF/B evaluations and 2) the lack of 'due consideration' of
Muchlisoh, Siti; Kurnia, Anang; Notodiputro, Khairil Anwar; Mangku, I. Wayan
2016-02-01
Labor force surveys conducted over time by the rotating panel design have been carried out in many countries, including Indonesia. Labor force survey in Indonesia is regularly conducted by Statistics Indonesia (Badan Pusat Statistik-BPS) and has been known as the National Labor Force Survey (Sakernas). The main purpose of Sakernas is to obtain information about unemployment rates and its changes over time. Sakernas is a quarterly survey. The quarterly survey is designed only for estimating the parameters at the provincial level. The quarterly unemployment rate published by BPS (official statistics) is calculated based on only cross-sectional methods, despite the fact that the data is collected under rotating panel design. The study purpose to estimate a quarterly unemployment rate at the district level used small area estimation (SAE) model by combining time series and cross-sectional data. The study focused on the application and comparison between the Rao-Yu model and dynamic model in context estimating the unemployment rate based on a rotating panel survey. The goodness of fit of both models was almost similar. Both models produced an almost similar estimation and better than direct estimation, but the dynamic model was more capable than the Rao-Yu model to capture a heterogeneity across area, although it was reduced over time.
Prospects for Precision Neutrino Cross Section Measurements
Energy Technology Data Exchange (ETDEWEB)
Harris, Deborah A. [Fermilab
2016-01-28
The need for precision cross section measurements is more urgent now than ever before, given the central role neutrino oscillation measurements play in the field of particle physics. The definition of precision is something worth considering, however. In order to build the best model for an oscillation experiment, cross section measurements should span a broad range of energies, neutrino interaction channels, and target nuclei. Precision might better be defined not in the final uncertainty associated with any one measurement but rather with the breadth of measurements that are available to constrain models. Current experience shows that models are better constrained by 10 measurements across different processes and energies with 10% uncertainties than by one measurement of one process on one nucleus with a 1% uncertainty. This article describes the current status of and future prospects for the field of precision cross section measurements considering the metric of how many processes, energies, and nuclei have been studied.
C. Yalcin; Gyürky, Gy.; Rauscher, T.; Kiss, G G; Özkan, N.; Güray, R T; Z. Halász; Szücs, T.; Fülöp, Zs.; Z. Korkulu; Somorjai, E.
2015-01-01
Astrophysical reaction rates, which are mostly derived from theoretical cross sections, are necessary input to nuclear reaction network simulations for studying the origin of $p$ nuclei. Past experiments have found a considerable difference between theoretical and experimental cross sections in some cases, especially for ($\\alpha$,$\\gamma$) reactions at low energy. Therefore, it is important to experimentally test theoretical cross section predictions at low, astrophysically relevant energies...
Calculating Cross Sections of Composite Interstellar Grains
Voshchinnikov, N V; Voshchinnikov, Nikolai V.; Mathis, John S.
1999-01-01
Interstellar grains may be composite collections of particles of distinct materials, including voids, agglomerated together. We determine the various optical cross sections of such composite grains, given the optical properties of each constituent, using an approximate model of the composite grain. We assume it consists of many concentric spherical layers of the various materials, each with a specified volume fraction. In such a case the usual Mie theory can be generalized and the extinction, scattering, and other cross sections determined exactly. We find that the ordering of the materials in the layering makes some difference to the derived cross sections, but averaging over the various permutations of the order of the materials provides rapid convergence as the number of shells (each of which is filled by all of the materials proportionately to their volume fractions) is increased. Three shells, each with one layer of a particular constituent material, give a very satisfactory estimate of the average cross...
Dashti-Naserabadi, H.; Najafi, M. N.
2015-05-01
We consider the three-dimensional (3D) Bak-Tang-Wiesenfeld model in a cubic lattice. Along with analyzing the 3D problem, the geometrical structure of the two-dimensional (2D) cross section of waves is investigated. By analyzing the statistical observables defined in the cross sections, it is shown that the model in that plane (named as 2D-induced model) is in the critical state and fulfills the finite-size scaling hypothesis. The analysis of the critical loops that are interfaces of the 2D-induced model is of special importance in this paper. Most importantly, we see that their fractal dimension is Df=1.387 ±0.005 , which is compatible with the fractal dimension of the external perimeter of geometrical spin clusters of 2D critical Ising model. Some hyperscaling relations between the exponents of the model are proposed and numerically confirmed. We then address the problem of conformal invariance of the mentioned domain walls using Schramm-Lowener evolution (SLE). We found that they are described by SLE with the diffusivity parameter κ =2.8 ±0.2 , nearly consistent with observed fractal dimension.
Spatio-temporal Rich Model Based Video Steganalysis on Cross Sections of Motion Vector Planes.
Tasdemir, Kasim; Kurugollu, Fatih; Sezer, Sakir
2016-05-11
A rich model based motion vector steganalysis benefiting from both temporal and spatial correlations of motion vectors is proposed in this work. The proposed steganalysis method has a substantially superior detection accuracy than the previous methods, even the targeted ones. The improvement in detection accuracy lies in several novel approaches introduced in this work. Firstly, it is shown that there is a strong correlation, not only spatially but also temporally, among neighbouring motion vectors for longer distances. Therefore, temporal motion vector dependency along side the spatial dependency is utilized for rigorous motion vector steganalysis. Secondly, unlike the filters previously used, which were heuristically designed against a specific motion vector steganography, a diverse set of many filters which can capture aberrations introduced by various motion vector steganography methods is used. The variety and also the number of the filter kernels are substantially more than that of used in previous ones. Besides that, filters up to fifth order are employed whereas the previous methods use at most second order filters. As a result of these, the proposed system captures various decorrelations in a wide spatio-temporal range and provides a better cover model. The proposed method is tested against the most prominent motion vector steganalysis and steganography methods. To the best knowledge of the authors, the experiments section has the most comprehensive tests in motion vector steganalysis field including five stego and seven steganalysis methods. Test results show that the proposed method yields around 20% detection accuracy increase in low payloads and 5% in higher payloads.
Wind Turbine Radar Cross Section
Directory of Open Access Journals (Sweden)
David Jenn
2012-01-01
Full Text Available The radar cross section (RCS of a wind turbine is a figure of merit for assessing its effect on the performance of electronic systems. In this paper, the fundamental equations for estimating the wind turbine clutter signal in radar and communication systems are presented. Methods of RCS prediction are summarized, citing their advantages and disadvantages. Bistatic and monostatic RCS patterns for two wind turbine configurations, a horizontal axis three-blade design and a vertical axis helical design, are shown. The unique electromagnetic scattering features, the effect of materials, and methods of mitigating wind turbine clutter are also discussed.
Mental Visualization of Objects from Cross-Sectional Images
Wu, Bing; Klatzky, Roberta L.; Stetten, George D.
2012-01-01
We extended the classic anorthoscopic viewing procedure to test a model of visualization of 3D structures from 2D cross-sections. Four experiments were conducted to examine key processes described in the model, localizing cross-sections within a common frame of reference and spatiotemporal integration of cross sections into a hierarchical object…
Francis, Z.; El Bitar, Z.; Incerti, S.; Bernal, M. A.; Karamitros, M.; Tran, H. N.
2017-07-01
This study presents new parameters for proton ionisation cross sections in guanine, adenine, thymine, and cytosine based upon the semi-empirical Rudd model. The same model was used to find differential electron cross sections considering a speed scaling procedure. To accelerate computation, the total electron cross sections were obtained using the binary-encounter-Bethe approximation instead of the integrated Rudd formula. The cross sections were implemented in the Geant4 simulation toolkit as Geant4-DNA processes, and simulations were carried out measuring protons lineal energies in spherical micrometric volumes filled with water, adenine, thymine, guanine, and cytosine. Large differences were seen in the lineal energies evaluated for the different materials, with the lineal energy measured in guanine being sometimes twice that of water. This suggests that the cross sections developed here should be considered in biological simulations where cellular substructures are modelled, in contrast to the current approach which approximates these volumes as consisting of liquid water.
Institute of Scientific and Technical Information of China (English)
钟晨; 蔡翔舟; 沈文庆; 张虎勇; 魏义彬; 陈金根; 马余刚; 郭威; 方德清
2003-01-01
The Boltzmann-Uehling-Uhlenbeck (BUU) model, which includes the Fermi motion, the mean field, individual nucleon-nucleon (N-N) interactions and the Pauli blocking effect, etc., is used to calculate the total reaction cross section σR induced by α-particles on different targets in the incident energy range from 17.4 to 48.1 MeV/u. The calculation result can well reproduce the experimental data. The nucleus-nucleus interaction radius parameterγ0 was extracted from experimental σR. It is found that γ0 becomes constant with the increasing mass number of target.
2010-10-01
... 46 Shipping 2 2010-10-01 2010-10-01 false Cross section. 64.25 Section 64.25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Standards for an MPT § 64.25 Cross section. A tank must have a cross section design that is— (a...
Directory of Open Access Journals (Sweden)
Erida Gjini
2016-03-01
Full Text Available The efficacy of vaccines is typically estimated prior to implementation, on the basis of randomized controlled trials. This does not preclude, however, subsequent assessment post-licensure, while mass-immunization and nonlinear transmission feedbacks are in place. In this paper we show how cross-sectional prevalence data post-vaccination can be interpreted in terms of pathogen transmission processes and vaccine parameters, using a dynamic epidemiological model. We advocate the use of such frameworks for model-based vaccine evaluation in the field, fitting trajectories of cross-sectional prevalence of pathogen strains before and after intervention. Using SI and SIS models, we illustrate how prevalence ratios in vaccinated and non-vaccinated hosts depend on true vaccine efficacy, the absolute and relative strength of competition between target and non-target strains, the time post follow-up, and transmission intensity. We argue that a mechanistic approach should be added to vaccine efficacy estimation against multi-type pathogens, because it naturally accounts for inter-strain competition and indirect effects, leading to a robust measure of individual protection per contact. Our study calls for systematic attention to epidemiological feedbacks when interpreting population level impact. At a broader level, our parameter estimation procedure provides a promising proof of principle for a generalizable framework to infer vaccine efficacy post-licensure.
Directory of Open Access Journals (Sweden)
Kaplan Abdullah
2015-01-01
Full Text Available Implementation of projects of new generation nuclear power plants requires the solving of material science and technological issues in developing of reactor materials. Melts of heavy metals (Pb, Bi and Pb-Bi due to their nuclear and thermophysical properties, are the candidate coolants for fast reactors and accelerator-driven systems (ADS. In this study, α, γ, p, n and 3He induced fission cross section calculations for 209Bi target nucleus at high-energy regions for (α,f, (γ,f, (p,f, (n,f and (3He,f reactions have been investigated using different fission reaction models. Mamdouh Table, Sierk, Rotating Liquid Drop and Fission Path models of theoretical fission barriers of TALYS 1.6 code have been used for the fission cross section calculations. The calculated results have been compared with the experimental data taken from the EXFOR database. TALYS 1.6 Sierk model calculations exhibit generally good agreement with the experimental measurements for all reactions used in this study.
Photodisintegration Cross Section of 241Am
Tonchev, A. P.; Hammond, S.; Howell, C. R.; Huibregtse, C.; Hutcheson, A.; Karwowski, H. J.; Kelley, J. H.; Kwan, E.; Rusev, G.; Tornow, W.; Vieira, D. J.; Wilhelmy, J. B.
2009-03-01
The photodisintegration cross section of radioactive 241Am has been obtained for the first time using monoenergetic γ-ray beams from the HIγS facility. The induced activity of 240Am produced via the 241Am(γ,n) reaction in the γ-ray energy range from 9.5 to 16 MeV was measured by the activation technique utilizing high resolution HPGe detectors. The 241Am(γ,n) cross section was determined both by measuring the absolute γ-ray flux and by comparison to the 197Au(γ,n) and 58Ni(γ,n) cross section standards. The experimental data for the 241Am(γ,n) reaction in the giant dipole resonance energy region is compared with statistical nuclear-model calculations.
NNLO QCD Corrections to the Drell-Yan Cross Section in Models of TeV-Scale Gravity
Ahmed, Taushif; Dhani, Prasanna K; Kumar, M C; Mathews, Prakash; Rana, Narayan; Ravindran, V
2016-01-01
The first results on the complete next-to-next-to-leading order (NNLO) Quantum Chromodynamic (QCD) corrections to the production of di-leptons at hadron colliders in large extra dimension models with spin-2 particles are reported in this article. In particular, we have computed these corrections to the invariant mass distribution of the di-leptons taking into account all the partonic subprocesses that contribute at NNLO. In these models, spin-2 particles couple through the energy-momentum tensor of the Standard Model (SM) with the universal coupling strength. The tensorial nature of the interaction and the presence of both quark annihilation and gluon fusion channels at the Born level make it challenging computationally and interesting phenomenologically. We have demonstrated numerically the importance of our results at the Large Hadron Collider (LHC) energies. The two loop corrections contribute an additional 10\\% to the total cross section. We find that the QCD corrections are not only large but also import...
Bilbao, Stefan; Harrison, Reginald
2016-07-01
Numerical modeling of wave propagation in acoustic tubes is a subject of longstanding interest, particularly for enclosures of varying cross section, and especially when viscothermal losses due to boundary layer effects are taken into consideration. Though steady-state, or frequency domain methods, are a common avenue of approach, recursive time domain methods are an alternative, allowing for the generation of wideband responses, and offer a point of departure for more general modeling of nonlinear wave propagation. The design of time-domain methods is complicated by numerical stability considerations, and to this end, a passive representation is a useful design principle leading to simple stable and explicit numerical schemes, particularly in the case of viscothermal loss modeling. Such schemes and the accompanying energy and stability analysis are presented here. Numerical examples are presented for a variety of duct profiles, illustrating strict energy dissipation, and for comparison of computed input impedances against frequency-domain results.
Boyarinov, V. F.; Grol, A. V.; Fomichenko, P. A.; Ternovykh, M. Yu
2017-01-01
This work is aimed at improvement of HTGR neutron physics design calculations by application of uncertainty analysis with the use of cross-section covariance information. Methodology and codes for preparation of multigroup libraries of covariance information for individual isotopes from the basic 44-group library of SCALE-6 code system were developed. A 69-group library of covariance information in a special format for main isotopes and elements typical for high temperature gas cooled reactors (HTGR) was generated. This library can be used for estimation of uncertainties, associated with nuclear data, in analysis of HTGR neutron physics with design codes. As an example, calculations of one-group cross-section uncertainties for fission and capture reactions for main isotopes of the MHTGR-350 benchmark, as well as uncertainties of the multiplication factor (k∞) for the MHTGR-350 fuel compact cell model and fuel block model were performed. These uncertainties were estimated by the developed technology with the use of WIMS-D code and modules of SCALE-6 code system, namely, by TSUNAMI, KENO-VI and SAMS. Eight most important reactions on isotopes for MHTGR-350 benchmark were identified, namely: 10B(capt), 238U(n,γ), ν5, 235U(n,γ), 238U(el), natC(el), 235U(fiss)-235U(n,γ), 235U(fiss).
Hu, Xingdi; Chen, Xinguang; Cook, Robert L.; Chen, Ding-Geng; Okafor, Chukwuemeka
2016-01-01
Background The probabilistic discrete event systems (PDES) method provides a promising approach to study dynamics of underage drinking using cross-sectional data. However, the utility of this approach is often limited because the constructed PDES model is often non-identifiable. The purpose of the current study is to attempt a new method to solve the model. Methods A PDES-based model of alcohol use behavior was developed with four progression stages (never-drinkers [ND], light/moderate-drinker [LMD], heavy-drinker [HD], and ex-drinker [XD]) linked with 13 possible transition paths. We tested the proposed model with data for participants aged 12–21 from the 2012 National Survey on Drug Use and Health (NSDUH). The Moore-Penrose (M-P) generalized inverse matrix method was applied to solve the proposed model. Results Annual transitional probabilities by age groups for the 13 drinking progression pathways were successfully estimated with the M-P generalized inverse matrix approach. Result from our analysis indicates an inverse “J” shape curve characterizing pattern of experimental use of alcohol from adolescence to young adulthood. We also observed a dramatic increase for the initiation of LMD and HD after age 18 and a sharp decline in quitting light and heavy drinking. Conclusion Our findings are consistent with the developmental perspective regarding the dynamics of underage drinking, demonstrating the utility of the M-P method in obtaining a unique solution for the partially-observed PDES drinking behavior model. The M-P approach we tested in this study will facilitate the use of the PDES approach to examine many health behaviors with the widely available cross-sectional data. PMID:26511344
2013-01-01
Background Understanding children’s physical activity motivation, its antecedents and associations with behavior is important and can be advanced by using self-determination theory. However, research among youth is largely restricted to adolescents and studies of motivation within certain contexts (e.g., physical education). There are no measures of self-determination theory constructs (physical activity motivation or psychological need satisfaction) for use among children and no previous studies have tested a self-determination theory-based model of children’s physical activity motivation. The purpose of this study was to test the reliability and validity of scores derived from scales adapted to measure self-determination theory constructs among children and test a motivational model predicting accelerometer-derived physical activity. Methods Cross-sectional data from 462 children aged 7 to 11 years from 20 primary schools in Bristol, UK were analysed. Confirmatory factor analysis was used to examine the construct validity of adapted behavioral regulation and psychological need satisfaction scales. Structural equation modelling was used to test cross-sectional associations between psychological need satisfaction, motivation types and physical activity assessed by accelerometer. Results The construct validity and reliability of the motivation and psychological need satisfaction measures were supported. Structural equation modelling provided evidence for a motivational model in which psychological need satisfaction was positively associated with intrinsic and identified motivation types and intrinsic motivation was positively associated with children’s minutes in moderate-to-vigorous physical activity. Conclusions The study provides evidence for the psychometric properties of measures of motivation aligned with self-determination theory among children. Children’s motivation that is based on enjoyment and inherent satisfaction of physical activity is
Sebire, Simon J; Jago, Russell; Fox, Kenneth R; Edwards, Mark J; Thompson, Janice L
2013-09-26
Understanding children's physical activity motivation, its antecedents and associations with behavior is important and can be advanced by using self-determination theory. However, research among youth is largely restricted to adolescents and studies of motivation within certain contexts (e.g., physical education). There are no measures of self-determination theory constructs (physical activity motivation or psychological need satisfaction) for use among children and no previous studies have tested a self-determination theory-based model of children's physical activity motivation. The purpose of this study was to test the reliability and validity of scores derived from scales adapted to measure self-determination theory constructs among children and test a motivational model predicting accelerometer-derived physical activity. Cross-sectional data from 462 children aged 7 to 11 years from 20 primary schools in Bristol, UK were analysed. Confirmatory factor analysis was used to examine the construct validity of adapted behavioral regulation and psychological need satisfaction scales. Structural equation modelling was used to test cross-sectional associations between psychological need satisfaction, motivation types and physical activity assessed by accelerometer. The construct validity and reliability of the motivation and psychological need satisfaction measures were supported. Structural equation modelling provided evidence for a motivational model in which psychological need satisfaction was positively associated with intrinsic and identified motivation types and intrinsic motivation was positively associated with children's minutes in moderate-to-vigorous physical activity. The study provides evidence for the psychometric properties of measures of motivation aligned with self-determination theory among children. Children's motivation that is based on enjoyment and inherent satisfaction of physical activity is associated with their objectively-assessed physical
Analytical Model of Inlet Growth and Equilibrium Cross-Sectional Area
2016-04-01
Sectional Area by Richard Styles PURPOSE: This Coastal and Hydraulics Engineering Technical Note (CHETN) focuses on inlet stability theory in...earlier treatments, Escoffier used the hydraulic radius instead of water depth in the friction term (Walton and Escoffier 1981). However, the ratio of...a0) tidal amplitude ratio. The details can be found in his original work and are not presented here except to note that Escoffier introduced two
Directory of Open Access Journals (Sweden)
U. Schneider
2009-01-01
Full Text Available The paper presents the structural application of a new thermal induced strain model for concrete – the TIS-Model. An advanced transient concrete model (ATCM is applied with the material model of the TIS-Model. The non-linear model comprises thermal strain, elastic strain, plastic strain and transient temperature strains, and load history modelling of restraint concrete structures subjected to fire.The calculations by finite element analysis (FEA were done using the SAFIR structural code. The FEA software was basically new with respect to the material modelling derived to use the new TIS-Model (as a transient model considers thermal induced strain. The equations of the ATCM consider a lot of capabilities, especially for considering irreversible effects of temperature on some material properties. By considering the load history during heating up, increasing load bearing capacity may be obtained due to higher stiffness of the concrete. With this model, it is possible to apply the thermal-physical behaviour of material laws for calculation of structures under extreme temperature conditions.A tunnel cross section designed and built by the cut and cover method is calculated with a tunnel fire curve. The results are compared with the results of a calculation with the model of the Eurocode 2 (EC2-Model. The effect of load history in highly loaded structures under fire load will be investigated.A comparison of this model with the ordinary calculation system of Eurocode 2 (EC2 shows that a better evaluation of the safety level was achieved with the new model. This opens a space for optimizing concrete structure design with transient temperature conditions up to 1000 °C.
On cross-section computation in the brane-world models
Dmitry, Kirpichnikov
2014-06-01
We present Mathematica7 numerical simulation of the process pp → jet + E/Tin the framework of modified Randall-Sundrum brane-world model with one infinite and n compact extra dimension. We compare the energy missing signature with the standard model background pp → jet + vbar v, which was simulated at CompHep. We show that the models with numbers of compact extra dimensions greater than 4 can be probed at the protons center-of-mass energy equal 14 TeV. We also find that testing the brane-world models at 7 TeV on the LHC appears to hopeless.
Hot DA white dwarf model atmosphere calculations: Including improved Ni PI cross sections
Preval, S P; Badnell, N R; Hubeny, I; Holberg, J B
2016-01-01
To calculate realistic models of objects with Ni in their atmospheres, accurate atomic data for the relevant ionization stages needs to be included in model atmosphere calculations. In the context of white dwarf stars, we investigate the effect of changing the Ni {\\sc iv}-{\\sc vi} bound-bound and bound-free atomic data has on model atmosphere calculations. Models including PICS calculated with {\\sc autostructure} show significant flux attenuation of up to $\\sim 80$\\% shortward of 180\\AA\\, in the EUV region compared to a model using hydrogenic PICS. Comparatively, models including a larger set of Ni transitions left the EUV, UV, and optical continua unaffected. We use models calculated with permutations of this atomic data to test for potential changes to measured metal abundances of the hot DA white dwarf G191-B2B. Models including {\\sc autostructure} PICS were found to change the abundances of N and O by as much as $\\sim 22$\\% compared to models using hydrogenic PICS, but heavier species were relatively unaf...
Schultz, D. R.; Ovchinnikov, S. Yu; Stancil, P. C.; Zaman, T.
2016-04-01
Updating and extending previous work (Krstić and Schultz 1999 J. Phys. B: At. Mol. Opt. Phys. 32 3458 and other references) comprehensive calculations were performed for elastic scattering and charge transfer in proton—atomic hydrogen collisions. The results, obtained for 1301 collision energies in the center-of-mass energy range of 10-4-104 eV, are provided for integral and differential cross sections relevant to transport modeling in astrophysical and other plasma environments, and are made available through a website. Use of the data is demonstrated through a Monte Carlo transport simulation of solar wind proton propagation through atomic hydrogen gas representing a simple model of the solar wind interaction with heliospheric neutrals.
Sheikin, E. G.
2017-08-01
The analytical differential cross section (DCS) of elastic scattering of atoms that reproduces the stopping power and the straggling of energy loss is proposed. Analytical expressions derived from the DCS for diffusion σd and viscosity σv cross sections of elastic collisions of atoms are in good agreement with known cross sections of 38Ar-40Ar and H-Li collisions obtained from quantum mechanical simulations. The Monte Carlo modeling of the transport of sputtered Cu atoms in Ar and implantation of Bi ions in B and C materials made using the proposed DCS demonstrates its accuracy in the modeling of elastic collisions.
Institute of Scientific and Technical Information of China (English)
Zafar Yasin; Warda Iram; Muhammad Asghar; M. Ikram Shahzad
2011-01-01
Fission cross sections strongly depend on the ratio of the level density parameter in fission to neutron emission,af/an.In this work,a cascade-exciton model implemented in the code CEM95 has been used to observe this effect for proton induced fission cross sections of tungsten,lead and bismuth.The method was employed using different level density parameter ratios for each fission cross section calculation.The calculated fission cross sections are compared with the available experimental data in the literature.It has been observed that a change of the ratio of the level density parameter,af/an,is necessary with the incident energy of the proton,to best estimate the fission cross sections in CEM95.
On cross-section computation in the brane-world models
Kirpichnikov, D V
2013-01-01
We present Mathematica7 numerical simulation of the process $pp\\rightarrow\\mbox{jet}+E_{T}^{miss}$ in the framework of modified Randall-Sundrum brane-world model with one infinite and $n$ compact extra dimension. We compare the energy missing signature with the standard model background $pp\\rightarrow \\mbox{jet}+\
Elementary School Students' Mental Models about Formation of Seasons: A Cross Sectional Study
Türk, Cumhur; Kalkan, Hüseyin; Kiroglu, Kasim; Ocak Iskeleli, Nazan
2016-01-01
The purpose of this study is to determine the mental models of elementary school students on seasons and to analyze how these models change in terms of grade levels. The study was conducted with 294 students (5th, 6th, 7th and 8th graders) studying in an elementary school of Turkey's Black Sea Region. Qualitative and quantitative data collection…
Energy Technology Data Exchange (ETDEWEB)
Murata, Toru [AITEL Corporation, Tokyo (Japan)
2000-03-01
Simple formulae to reproduce the optical model compound nucleus formation cross sections for neutron, proton, deuteron, triton, {sup 3}He and alpha particles are presented for target nuclei of light to medium weight mass region. (author)
Measurement of the Standard Model $ZZ$ Cross-Section in the $ZZ \\to \\ell\\ell\\ell\\ell$ Channel
Energy Technology Data Exchange (ETDEWEB)
Rodriguez, Tatiana Isabel [Univ. of Pennsylvania, Philadelphia, PA (United States)
2011-01-01
In this thesis we study one of the last corners of the Standard Model to be thoroughly investigated in a hadron collider, the production of two simultaneous Z bosons. We analyze 6.1 fb^{-1} of data produced at Fermilab at a center-of-mass energy √s = 1.96 TeV and recorded by the CDF experiment. The predicted cross-section is 1.4 pb and we measured 2.18^{+0.64 }_{-0.63} pb (stat) 0:30 (syst) using 14 observed events. This is the largest set of candidate events in this channel yet found and with our estimated signal in the sample of 9.54 events provides the smallest percentage uncertainty on the ZZ cross-section to date. We also use this large set of events to yield kinematic plots and measure ZZ properties that will be of use in probing for new physics in the future.
Determinants of orthodontic treatment need and demand: a cross-sectional path model study.
Taghavi Bayat, Jari; Huggare, Jan; Mohlin, Bengt; Akrami, Nazar
2017-02-01
To put forward a model predicting orthodontic treatment need and demand. Furthermore, to explore how much of the variance in treatment demand could be explained by a set of self-assessed measures, and how these measures relate to professionally assessed treatment need. One hundred and fifty adolescents, aged 13 years, completed a questionnaire which included a set of self-assessed measures dealing with self-esteem, such as dental and global self-esteem, various aspects of malocclusion, such as perceived malocclusion and perceived functional limitation, and treatment demand. Treatment need was assessed by Dental Health Component of the Index of Orthodontic Treatment Need grading. Path analysis was used to examine the relations between the measures and if they could predict treatment need and demand. The measures proved to be reliable and inter-correlated. Path analysis revealed that the proposed model had good fit to the data, providing a test of the unique effect of all included measures on treatment need and demand. The model explained 33% of the variance in treatment demand and 22% of the variance in treatment need. The specific age group could affect the generalizability of the findings. Moreover, although showing good fit to data, the final model is based on a combination of theoretical reasoning and semi-explorative approach. The proposed model displays the unique effect of each included measure on treatment need and demand, explaining a large proportion of the variance in perceived treatment demand and professionally assessed treatment need. The model would hopefully lead to improved and more cost-efficient predictions of treatment need and demand. © The Author 2016. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.
Wilmouth, D. M.; Klobas, J. E.; Anderson, J. G.
2015-12-01
Thirty years have now passed since the discovery of the Antarctic ozone hole, and despite comprehensive international agreements being in place to phase out CFCs and halons, polar ozone losses generally remain severe. The relevant halogen compounds have very long atmospheric lifetimes, which ensures that seasonal polar ozone depletion will likely continue for decades to come. Changes in the climate system can further impact stratospheric ozone abundance through changes in the temperature and water vapor structure of the atmosphere and through the potential initiation of solar radiation management efforts. In many ways, the rate at which climate is changing must now be considered fast relative to the slow removal of halogens from the atmosphere. Photochemical models of Earth's atmosphere play a critical role in understanding and projecting ozone levels, but in order for these models to be accurate, they must be built on a foundation of accurate laboratory data. ClOOCl is the centerpiece of the catalytic cycle that accounts for more than 50% of the chlorine-catalyzed ozone loss in the Arctic and Antarctic stratosphere every spring, and so uncertainties in the ultraviolet cross sections of ClOOCl are particularly important. Additionally, the equilibrium constant of the dimerization reaction of ClO merits further study, as there are important discrepancies between in situ measurements and lab-based models, and the JPL-11 recommended equilibrium constant includes high error bars at atmospherically relevant temperatures (~75% at 200 K). Here we analyze available data for the ClOOCl ultraviolet cross sections and equilibrium constant and present new laboratory spectroscopic results.
SNL RML recommended dosimetry cross section compendium
Energy Technology Data Exchange (ETDEWEB)
Griffin, P.J.; Kelly, J.G.; Luera, T.F. [Sandia National Labs., Albuquerque, NM (United States); VanDenburg, J. [Science and Engineering Associates, Inc., Albuquerque, NM (United States)
1993-11-01
A compendium of dosimetry cross sections is presented for use in the characterization of fission reactor spectrum and fluence. The contents of this cross section library are based upon the ENDF/B-VI and IRDF-90 cross section libraries and are recommended as a replacement for the DOSCROS84 multigroup library that is widely used by the dosimetry community. Documentation is provided on the rationale for the choice of the cross sections selected for inclusion in this library and on the uncertainty and variation in cross sections presented by state-of-the-art evaluations.
[Fast neutron cross section measurements
Energy Technology Data Exchange (ETDEWEB)
Knoll, G.F.
1992-10-26
From its inception, the Nuclear Data Project at the University of Michigan has concentrated on two major objectives: (1) to carry out carefully controlled nuclear measurements of the highest possible reliability in support of the national nuclear data program, and (2) to provide an educational opportunity for students with interests in experimental nuclear science. The project has undergone a successful transition from a primary dependence on our photoneutron laboratory to one in which our current research is entirely based on a unique pulsed 14 MeV fast neutron facility. The new experimental facility is unique in its ability to provide nanosecond bursts of 14 MeV neutrons under conditions that are clean'' and as scatter-free as possible, and is the only one of its type currently in operation in the United States. It has been designed and put into operation primarily by graduate students, and has met or exceeded all of its important initial performance goals. We have reached the point of its routine operation, and most of the data are now in hand that will serve as the basis for the first two doctoral dissertations to be written by participating graduate students. Our initial results on double differential neutron cross sections will be presented at the May 1993 Fusion Reactor Technology Workshop. We are pleased to report that, after investing several years in equipment assembly and optimization, the project has now entered its data production'' phase.
A cross-sectional model of eating disorders in Argentinean overweight and obese children.
Elizathe, Luciana Soledad; Arana, Fernán Guido; Rutsztein, Guillermina
2016-09-27
Despite the fact that past research identified childhood obesity as an antecedent of eating disorders, not all obese children further develop this pathology. With this regard, our first purpose was to isolate which characteristics differentiate overweight children who have an eating disorder from those who have not. Second, considering that there is little evidence collected in Latin American countries, we provided overweight children data from an Argentinean sample. Specifically, we investigated if weight-teasing, perfectionism, disturbed eating attitudes and behaviors, and body image dissatisfaction are related to the occurrence of an eating disorder in 100 school-aged overweight/obese children (37 girls and 63 boys; mean age 10.85, SD 0.88). Participants completed self-report instruments and were interviewed between 1 and 2 months later to confirm the presence of eating disorders. Seventeen percent participants confirmed to have an eating disorder. Further, the multivariate logistic analysis revealed that perfectionism (Exp β = 1.19) and disturbed eating attitudes and behaviors (Exp β = 4.78) were jointly associated with the presence of an eating disorder. These results were maintained even when the overall model was adjusted for covariates such as age, gender, body mass index, and school type. Weight-teasing and body image dissatisfaction did not contribute to the multivariate model. Prevalence rates of ED and model findings were discussed.
Chinese Nurses' Acceptance of PDA: A Cross-Sectional Survey Using a Technology Acceptance Model.
Wang, Yanling; Xiao, Qian; Sun, Liu; Wu, Ying
2016-01-01
This study explores Chinese nurses' acceptance of PDA, using a questionnaire based on the framework of Technology Acceptance Model (TAM). 357 nurses were involved in the study. The results reveal the scores of the nurses' acceptance of PDA were means 3.18~3.36 in four dimensions. The younger of nurses, the higher nurses' title, the longer previous usage time, the more experienced using PDA, and the more acceptance of PDA. Therefore, the hospital administrators may change strategies to enhance nurses' acceptance of PDA, and promote the wide application of PDA.
Double parton scattering: A study of the effective cross section within a Light-Front quark model
Directory of Open Access Journals (Sweden)
Matteo Rinaldi
2016-01-01
Full Text Available We present a calculation of the effective cross section σeff, an important ingredient in the description of double parton scattering in proton–proton collisions. Our theoretical approach makes use of a Light-Front quark model as a framework to calculate the double parton distribution functions at low-resolution scale. QCD evolution is implemented to reach the experimental scale. The obtained values of σeff in the valence region are consistent with the present experimental scenario, in particular with the sets of data which include the same kinematical range. However the result of the complete calculation shows a dependence of σeff on xi, a feature not easily seen in the available data, probably because of their low accuracy. Measurements of σeff in restricted xi regions are addressed to obtain indications on double parton correlations, a novel and interesting aspect of the three dimensional structure of the nucleon.
Radar cross section measurements using terahertz waves
DEFF Research Database (Denmark)
Iwaszczuk, Krzysztof; Heiselberg, Henning; Jepsen, Peter Uhd
2010-01-01
Radar cross sections at terahertz frequencies are measured on scale models of aircrafts. A time domain broadband THz system generates freely propagating THz pulses measured with sub-picosecond time resolution. The THz radiation is generated using fs laser pulses by optical rectification in a lith......Radar cross sections at terahertz frequencies are measured on scale models of aircrafts. A time domain broadband THz system generates freely propagating THz pulses measured with sub-picosecond time resolution. The THz radiation is generated using fs laser pulses by optical rectification...... in a lithium niobate crystal with application of the tilted wave front method, resulting in high electric field THz pulses with a broad band spectrum from 100 GHz up to 4 THz. The corresponding wave lengths are two orders of magnitude smaller than normal radars and we therefore use scale models of size 5-10 cm...... in order to measure realistic radar cross sections. RCS polar and azimuthal angle plots of F-16 and F-35 are presented....
NNLO QCD corrections to the Drell-Yan cross section in models of TeV-scale gravity
Ahmed, Taushif; Banerjee, Pulak; Dhani, Prasanna K.; Kumar, M. C.; Mathews, Prakash; Rana, Narayan; Ravindran, V.
2017-01-01
The first results on the complete next-to-next-to-leading order (NNLO) Quantum Chromodynamic (QCD) corrections to the production of di-leptons at hadron colliders in large extra dimension models with spin-2 particles are reported in this article. In particular, we have computed these corrections to the invariant mass distribution of the di-leptons taking into account all the partonic sub-processes that contribute at NNLO. In these models, spin-2 particles couple through the energy-momentum tensor of the Standard Model with the universal coupling strength. The tensorial nature of the interaction and the presence of both quark annihilation and gluon fusion channels at the Born level make it challenging computationally and interesting phenomenologically. We have demonstrated numerically the importance of our results at Large Hadron Collider energies. The two-loop corrections contribute an additional 10% to the total cross section. We find that the QCD corrections are not only large but also important to make the predictions stable under renormalisation and factorisation scale variations, providing an opportunity to stringently constrain the parameters of the models with a spin-2 particle.
NNLO QCD corrections to the Drell-Yan cross section in models of TeV-scale gravity
Energy Technology Data Exchange (ETDEWEB)
Ahmed, Taushif; Banerjee, Pulak; Dhani, Prasanna K.; Rana, Narayan [The Institute of Mathematical Sciences, Chennai, Tamil Nadu (India); Homi Bhabha National Institute, Mumbai (India); Kumar, M.C. [Indian Institute of Technology Guwahati, Department of Physics, Guwahati (India); Mathews, Prakash [Saha Institute of Nuclear Physics, Kolkata, West Bengal (India); Ravindran, V. [The Institute of Mathematical Sciences, Chennai, Tamil Nadu (India)
2017-01-15
The first results on the complete next-to-next-to-leading order (NNLO) Quantum Chromodynamic (QCD) corrections to the production of di-leptons at hadron colliders in large extra dimension models with spin-2 particles are reported in this article. In particular, we have computed these corrections to the invariant mass distribution of the di-leptons taking into account all the partonic sub-processes that contribute at NNLO. In these models, spin-2 particles couple through the energy-momentum tensor of the Standard Model with the universal coupling strength. The tensorial nature of the interaction and the presence of both quark annihilation and gluon fusion channels at the Born level make it challenging computationally and interesting phenomenologically. We have demonstrated numerically the importance of our results at Large Hadron Collider energies. The two-loop corrections contribute an additional 10% to the total cross section. We find that the QCD corrections are not only large but also important to make the predictions stable under renormalisation and factorisation scale variations, providing an opportunity to stringently constrain the parameters of the models with a spin-2 particle. (orig.)
Pola, Marco; Zampieri, Dario; Fabbri, Paolo
2010-05-01
The Euganean geothermal field (EGF) is the most important thermal field in the northern Italy. It is located in the Veneto alluvial plain, southwest of Padova (NE Italy). The EGF extends on a plain band of 36 km² located immediately northeast of the Euganei Hills. In this area about 100 mining claims and more than 400 wells have been drilled. Thermal waters are mainly used for cure and wellness, with a subsidiary use as energy to heat hotels and greenhouses. At present about 250 wells are active and the total average flow rate of thermal fluids is about 17 Mm³/year. The present hydrogeological conceptual model of the Euganean thermal circuit proposes that the thermal groundwaters are of meteoric origin and infiltrate at about 1500 m a.s.l. in the Pre - Alps, 70 Km to the north of the Euganei Hills. The waters reach a depth of about 3000 m, warm up by a normal geothermal gradient and flow into a fractured carbonate reservoir. Near the Euganei Hills, the groundwaters intercept a regional fault system (Schio - Vicenza fault system) that acts as a barrier for the groundwater flow. The high fracturing of the rocks in this area allows the hydrothermal fluid to rise quickly. It is increasingly found that hot waters outflow is related to local bends or stepovers of regional strike-slip faults. Also the active Schio - Vicenza fault system, which presently has a strike-slip kinematics, shows a geometric complexity that could produce a local extensional regime enhancing the outflow of the thermal fluid. The aim of this work is to construct a standard cross section of the hydrothermal circuit linked to EGF by using different type of geological and geophysical information (seismic sections, deep wells, geological maps of the subsurface). The standard section will be used to improve the conceptual model of thermal circuit and will be the base of the 2D mathematical hydrothermal model of Euganean thermal circuit, which will be performed using the software Hydrotherm. This
Electron capture cross sections for stellar nucleosynthesis
Giannaka, P G
2015-01-01
In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasi-particle random-phase approximation (pn-QRPA) and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the above mentioned $e^-$-capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the $^{66}Zn$ isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.
Cucinotta, Francis A.; Kim, Myung-Hee; Schneider, Irene; Hassler, Donald M.
2006-01-01
The atmosphere of Mars significantly attenuates the heavy ion component of the primary galactic cosmic rays (GCR), however increases the fluence of secondary light ions (neutrons, and hydrogen and helium isotopes) because of particle production processes. We describe results of the quantum multiple scattering fragmentation (QMSFRG) model for the production of light nuclei through the distinct mechanisms of nuclear abrasion and ablation, coalescence, and cluster knockout. The QMSFRG model is shown to be in excellent agreement with available experimental data for nuclear fragmentation cross sections. We use the QMSFRG model and the space radiation transport code, HZETRN to make predictions of the light particle environment on the Martian surface at solar minimum and maximum. The radiation assessment detector (RAD) experiment will be launched in 2009 as part of the Mars Science Laboratory (MSL). We make predictions of the expected results for time dependent count-rates to be observed by RAD experiment. Finally, we consider sensitivity assessments of the impact of the Martian atmospheric composition on particle fluxes at the surface.
Mascherek, Anna C; Gehring, Katrin; Bezzola, Paula; Schwappach, David L B
2015-10-07
Compliance with surgical checklist use remains an obstacle in the context of checklist implementation programs. The theory of planned behaviour was applied to analyse attitudes, perceived behaviour control, and norms as psychological antecedents of individuals' intentions to use the checklist. A cross-sectional survey study with staff (N = 866) of 10 Swiss hospitals was conducted in German and French. Group mean differences between individuals with and without managerial function were computed. Structural equation modelling and confirmatory factor analysis was applied to investigate the structural relation between attitudes, perceived behaviour control, norms, and intentions. Significant mean differences in favour of individuals with managerial function emerged for norms, perceived behavioural control, and intentions, but not for attitudes. Attitudes and perceived behavioural control had a significant direct effect on intentions whereas norms had not. Individuals with managerial function exhibit stronger perceived behavioural control, stronger norms, and stronger intentions. This could be applied in facilitating checklist implementation. The structural model of the theory of planned behaviour remains stable across groups, indicating a valid model to describe antecedents of intentions in the context of surgical checklist implementation.
Vertically stabilized elongated cross-section tokamak
Sheffield, George V.
1977-01-01
This invention provides a vertically stabilized, non-circular (minor) cross-section, toroidal plasma column characterized by an external separatrix. To this end, a specific poloidal coil means is added outside a toroidal plasma column containing an endless plasma current in a tokamak to produce a rectangular cross-section plasma column along the equilibrium axis of the plasma column. By elongating the spacing between the poloidal coil means the plasma cross-section is vertically elongated, while maintaining vertical stability, efficiently to increase the poloidal flux in linear proportion to the plasma cross-section height to achieve a much greater plasma volume than could be achieved with the heretofore known round cross-section plasma columns. Also, vertical stability is enhanced over an elliptical cross-section plasma column, and poloidal magnetic divertors are achieved.
Cross Sections for Electron Collisions with Methane
Energy Technology Data Exchange (ETDEWEB)
Song, Mi-Young, E-mail: mysong@nfri.re.kr; Yoon, Jung-Sik [Plasma Technology Research Center, National Fusion Research Institute, 814-2 Osikdo-dong, Gunsan, Jeollabuk-do 573-540 (Korea, Republic of); Cho, Hyuck [Department of Physics, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Itikawa, Yukikazu [Institute of Space and Astronautical Science, Sagamihara 252-5210 (Japan); Karwasz, Grzegorz P. [Faculty of Physics, Astronomy and Applied Informatics, University Nicolaus Copernicus, Grudziadzka 5, 87100 Toruń (Poland); Kokoouline, Viatcheslav [Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States); Nakamura, Yoshiharu [6-1-5-201 Miyazaki, Miyamae, Kawasaki 216-0033 (Japan); Tennyson, Jonathan [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)
2015-06-15
Cross section data are compiled from the literature for electron collisions with methane (CH{sub 4}) molecules. Cross sections are collected and reviewed for total scattering, elastic scattering, momentum transfer, excitations of rotational and vibrational states, dissociation, ionization, and dissociative attachment. The data derived from swarm experiments are also considered. For each of these processes, the recommended values of the cross sections are presented. The literature has been surveyed through early 2014.
Annular-Cross-Section CFE Chamber
Sharnez, Rizwan; Sammons, David W.
1994-01-01
Proposed continuous-flow-electrophoresis (CFE) chamber of annular cross section offers advantages over conventional CFE chamber, and wedge-cross-section chamber described in "Increasing Sensitivity in Continuous-Flow Electrophoresis" (MFS-26176). In comparison with wedge-shaped chamber, chamber of annular cross section virtually eliminates such wall effects as electro-osmosis and transverse gradients of velocity. Sensitivity enhanced by incorporating gradient maker and radial (collateral) flow.
Improved Empirical Parametrization of Fragmentation Cross Sections
Sümmerer, Klaus
2012-01-01
A new version is proposed for the universal empirical formula, EPAX, which describes fragmentation cross sections in high-energy heavy-ion reactions. The new version, EPAX 3, can be shown to yield cross sections that are in better agreement with experimental data for the most neutron-rich fragments than the previous version. At the same time, the very good agreement of EPAX 2 with data on the neutron-deficient side has been largely maintained. Comparison with measured cross sections show that the bulk of the data is reproduced within a factor of about 2, for cross sections down to the pico-barn range.
Maxwell, Scott E.; Cole, David A.; Mitchell, Melissa A.
2011-01-01
Maxwell and Cole (2007) showed that cross-sectional approaches to mediation typically generate substantially biased estimates of longitudinal parameters in the special case of complete mediation. However, their results did not apply to the more typical case of partial mediation. We extend their previous work by showing that substantial bias can…
Directory of Open Access Journals (Sweden)
Abdurrahman Charkazi
2016-07-01
Full Text Available teeth and T=permanent teeth has been increasing from 1957 to 2015 years in Iran. The current survey aimed to test the power of health promotion model for predicting the oral health behavior among high-school students. Materials and Methods: A cross-sectional study was conducted on 482 high school students in Gorgan city, Iran. Multi-cluster sampling was used to recruit the samples. A researcher-made questionnaire based on HPM was implemented to collect data. To analyze, SPSS-18 and statistical tests, including t-test, Pearson correlation coefficient and univariate and multivariate regression models were used. Results: A total of 482 high-school students including 255 (52.9% male and 227 (47.1% with mean age of 16.02 ± 0.5 were investigated. The highest and lowest prevalent positive oral health behavior were tooth brushing (73% and using fluidized oral irrigator (3.6%, respectively. Except for perceived barriers (with negative correlation, all constructs of HBM were positively related to oral health behaviors. Self-efficacy was the strongest predictor of oral health behavior (β=0.653 (r=0.541, P
White, Nicholas A; Moreno, Daniel P; Gayzik, F Scott; Stitzel, Joel D
2015-01-01
Human body finite element (FE) models are beginning to play a more prevalent role in the advancement of automotive safety. A methodology has been developed to evaluate neck response at multiple levels in a human body FE model during simulated automotive impacts. Three different impact scenarios were simulated: a frontal impact of a belted driver with airbag deployment, a frontal impact of a belted passenger without airbag deployment and an unbelted side impact sled test. Cross sections were created at each vertebral level of the cervical spine to calculate the force and moment contributions of different anatomical components of the neck. Adjacent level axial force ratios varied between 0.74 and 1.11 and adjacent level bending moment ratios between 0.55 and 1.15. The present technique is ideal for comparing neck forces and moments to existing injury threshold values, calculating injury criteria and for better understanding the biomechanical mechanisms of neck injury and load sharing during sub-injurious and injurious loading.
Neutrino Cross Sections at Solar Energies
Strigari, Louis
2017-01-01
I will review neutrino nucleus cross section measurements and uncertainties for energies applicable to solar neutrinos. I will discuss how these cross sections are important for interpreting solar neutrino experimental data, and highlight the most important neutrino-nucleus interactions that will be relevant for forthcoming dark matter direct detection experiments. NSF PHY-1522717.
Rostami, R
2016-01-01
To investigate the high mass dilepton production cross section produced due to the Drell-Yan process in hadronic collisions such as nucleon- nucleus, the valence and sea quarks distribution functions inside nucleus is used. In this study, in the framework of the shell and Fermi gas models, by adding quarks distribution functions of pions inside nucleus besides the quarks distribution functions of bound nucleons, the changes in the dilepton production cross section were investigated. For this reason, pionic contribution in the structure function of 63Cunucleus and its EMC ratio was first studied using the aforementioned models. Then, in the framework of the Drell-Yan process using GRV's nucleons and pions quarks distribution functions, the high mass dilepton production cross section in p-cu collision was calculated and compared with the available experimental data. The extracted results, based on the two mentioned models, were greatly the same and by considering the pionic contribution, the theoretical results...
Saha, P. K.; Zhang, H.; Sonka, M.; Christensen, G. E.; Rajapakse, C. S.
2007-03-01
Recent advancements in digital medical imaging have opened avenues for quantitative analyses of different volumetric and morphometric indices in response to a disease or a treatment. However, a major challenge in performing such an analysis is the lack of a technology of building a mean anatomic space (MAS) that allows mapping data of a given subject onto MAS. This approach leads to a tool for point-by-point regional analysis and comparison of quantitative indices for data coming from a longitudinal or transverse study. Toward this goal, we develop a new computation technique, called Active Index Model (AIM), which is a unique tool to solve the stated problem. AIM consists of three building blocks - (1) development of MAS for a particular anatomic site, (2) mapping a specific data onto MAS, (3) regional statistical analysis of data from different populations assessing regional response to a disease or treatment progression. The AIM presented here is built at the training phase from two known populations (e.g., normal and diseased) which will be immediately ready for diagnostic purpose in a subject whose clinical status is unknown. AIM will be useful for both cross sectional and longitudinal studies and for early diagnostic. This technique will be a vital tool for understanding regional response of a disease or treatment at various stages of its progression. This method has been applied for analyzing regional trabecular bone structural distribution in rabbit femur via micro-CT imaging and to localize the affected myocardial regions from cardiac MR data.
Directory of Open Access Journals (Sweden)
Krzysztof Buczkowski
2017-01-01
Full Text Available Tobacco smoking is the single most important modifiable factor in increased morbidity and premature mortality. Numerous factors—including genetics, personality, and environment—affect the development and persistence of tobacco addiction, and knowledge regarding these factors could improve smoking cessation rates. This study compared personality traits between never, former, and current smokers, using the Five-Factor Model of Personality in a country with a turbulent smoking reduction process.: In this cross-sectional study, 909 Polish adults completed the Revised Neuroticism-Extraversion-Openness Personality Inventory. Our results showed that current smokers’ scores for extraversion, one of the five global dimensions of personality, were higher relative to never smokers. Neuroticism, openness to experience, agreeableness, and conscientiousness did not differ significantly according to smoking status. Facet analysis, which described each dimension in detail, showed that current smokers’ activity and excitement seeking (facets of extraversion scores were higher relative to those of never and former smokers. In turn, current smokers’ dutifulness and deliberation (facets of conscientiousness scores were lower than those found in former and never smokers. Never smokers scored the highest in self-consciousness (a facet of neuroticism and compliance (a component of agreeableness. The study conducted among Polish individuals showed variation in personality traits according to their smoking status; however, this variation differed from that reported in countries in which efforts to reduce smoking had begun earlier relative to Poland. Knowledge regarding personality traits could be useful in designing smoking prevention and cessation programs tailored to individuals’ needs.
Buczkowski, Krzysztof; Basinska, Małgorzata A.; Ratajska, Anna; Lewandowska, Katarzyna; Luszkiewicz, Dorota; Sieminska, Alicja
2017-01-01
Tobacco smoking is the single most important modifiable factor in increased morbidity and premature mortality. Numerous factors—including genetics, personality, and environment—affect the development and persistence of tobacco addiction, and knowledge regarding these factors could improve smoking cessation rates. This study compared personality traits between never, former, and current smokers, using the Five-Factor Model of Personality in a country with a turbulent smoking reduction process.: In this cross-sectional study, 909 Polish adults completed the Revised Neuroticism-Extraversion-Openness Personality Inventory. Our results showed that current smokers’ scores for extraversion, one of the five global dimensions of personality, were higher relative to never smokers. Neuroticism, openness to experience, agreeableness, and conscientiousness did not differ significantly according to smoking status. Facet analysis, which described each dimension in detail, showed that current smokers’ activity and excitement seeking (facets of extraversion) scores were higher relative to those of never and former smokers. In turn, current smokers’ dutifulness and deliberation (facets of conscientiousness) scores were lower than those found in former and never smokers. Never smokers scored the highest in self-consciousness (a facet of neuroticism) and compliance (a component of agreeableness). The study conducted among Polish individuals showed variation in personality traits according to their smoking status; however, this variation differed from that reported in countries in which efforts to reduce smoking had begun earlier relative to Poland. Knowledge regarding personality traits could be useful in designing smoking prevention and cessation programs tailored to individuals’ needs. PMID:28134805
Buczkowski, Krzysztof; Basinska, Małgorzata A; Ratajska, Anna; Lewandowska, Katarzyna; Luszkiewicz, Dorota; Sieminska, Alicja
2017-01-27
Tobacco smoking is the single most important modifiable factor in increased morbidity and premature mortality. Numerous factors-including genetics, personality, and environment-affect the development and persistence of tobacco addiction, and knowledge regarding these factors could improve smoking cessation rates. This study compared personality traits between never, former, and current smokers, using the Five-Factor Model of Personality in a country with a turbulent smoking reduction process.: In this cross-sectional study, 909 Polish adults completed the Revised Neuroticism-Extraversion-Openness Personality Inventory. Our results showed that current smokers' scores for extraversion, one of the five global dimensions of personality, were higher relative to never smokers. Neuroticism, openness to experience, agreeableness, and conscientiousness did not differ significantly according to smoking status. Facet analysis, which described each dimension in detail, showed that current smokers' activity and excitement seeking (facets of extraversion) scores were higher relative to those of never and former smokers. In turn, current smokers' dutifulness and deliberation (facets of conscientiousness) scores were lower than those found in former and never smokers. Never smokers scored the highest in self-consciousness (a facet of neuroticism) and compliance (a component of agreeableness). The study conducted among Polish individuals showed variation in personality traits according to their smoking status; however, this variation differed from that reported in countries in which efforts to reduce smoking had begun earlier relative to Poland. Knowledge regarding personality traits could be useful in designing smoking prevention and cessation programs tailored to individuals' needs.
Energy Technology Data Exchange (ETDEWEB)
Kaplan, A., E-mail: abdullahkaplan@sdu.edu.tr [Süleyman Demirel Univesity, Faculty of Arts and Sciences, Department of Physics (Turkey); Sarpün, İ. H. [Afyon Kocatepe University, Faculty of Arts and Sciences, Department of Physics (Turkey); Aydın, A. [Kırıkkale University, Faculty of Arts and Sciences, Department of Physics (Turkey); Tel, E. [Osmaniye Korkut Ata University, Faculty of Arts and Sciences, Department of Physics (Turkey); Çapalı, V.; Özdoǧan, H. [Süleyman Demirel Univesity, Faculty of Arts and Sciences, Department of Physics (Turkey)
2015-01-15
There are several level density models that can be used to predict photo-neutron cross sections. Some of them are Constant Temperature + Fermi Gas Model (CTFGM), Back-Shifted Fermi Gas Model (BSFM), Generalized Superfluid Model (GSM), Hartree-Fock-Bogoliubov microscopic Model (HFBM). In this study, the theoretical photo-neutron cross sections produced by (γ, 2n) reactions for several eveneven lanthanide nuclei such as {sup 140,142}Ce, {sup 142,144,146,148,150}Nd, {sup 144,148,150,152,154}Sm, and {sup 160}Gd have been calculated on the different level density models as mentioned above by using TALYS 1.6 and EMPIRE 3.1 computer codes for incident photon energies up to 30 MeV. The obtained results have been compared with each other and available experimental data existing in the EXFOR database. Generally, at least one level density model cross-section calculations are in agreement with the experimental results for all reactions except {sup 144}Sm(γ, 2n){sup 142}Sm along the incident photon energy, TALYS 1.6 BSFM option for the level density model cross-section calculations can be chosen if the experimental data are not available or are improbable to be produced due to the experimental difficulty.
Recommended evaluation procedure for photonuclear cross section
Energy Technology Data Exchange (ETDEWEB)
Lee, Young-Ouk; Chang, Jonghwa; Fukahori, Tokio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1998-03-01
In order to generate photonuclear cross section library for the necessary applications, data evaluation is combined with theoretical evaluation, since photonuclear cross sections measured cannot provide all necessary data. This report recommends a procedure consisting of four steps: (1) analysis of experimental data, (2) data evaluation, (3) theoretical evaluation and, if necessary, (4) modification of results. In the stage of analysis, data obtained by different measurements are reprocessed through the analysis of their discrepancies to a representative data set. In the data evaluation, photonuclear absorption cross sections are evaluated via giant dipole resonance and quasi-deutron mechanism. With photoabsorption cross sections from the data evaluation, theoretical evaluation is applied to determine various decay channel cross sections and emission spectra using equilibrium and preequilibrium mechanism. After this, the calculated results are compared with measured data, and in some cases the results are modified to better describe measurements. (author)
Nuclear interaction cross sections for proton radiotherapy
Chadwick, M B; Arendse, G J; Cowley, A A; Richter, W A; Lawrie, J J; Newman, R T; Pilcher, J V; Smit, F D; Steyn, G F; Koen, J W; Stander, J A
1999-01-01
Model calculations of proton-induced nuclear reaction cross sections are described for biologically-important targets. Measurements made at the National Accelerator Centre are presented for double-differential proton, deuteron, triton, helium-3 and alpha particle spectra, for 150 and 200 MeV protons incident on C, N, and O. These data are needed for Monte Carlo simulations of radiation transport and absorbed dose in proton therapy. Data relevant to the use of positron emission tomography to locate the Bragg peak are also described.
Energy Technology Data Exchange (ETDEWEB)
Brassart, M. [Ecole Nationale Superieure Ingenieurs de Bourges, 18 - Bourges (France); Mounier, C. [CEA Saclay, Dir. de l' Energie Nucleaire DEN, Service d' Etudes des Reacteurs et de Modelisation Avancee, 91 - Gif sur Yvette (France); Dossantos-Uzarralde, P. [CEA Bruyeres le Chatel, 91 (France). Dept. de Physique Theorique et Appliquee
2004-07-01
Nuclear reaction models play an important role in today's nuclear data evaluations. There are, however, difficulties associated with evaluating data uncertainties, both while performing the experimental measurements as well as constructing them by nuclear models. In this general context, our interest is particularly targeted towards the study of the propagation uncertainties within nuclear models. In this report we discuss two distinct ways of calculating the nuclear cross section variance-covariance matrices and then show these can be applied to the nuclear spherical optical model. (authors)
Mascherek, Anna C; Gehring, Katrin; Bezzola, Paula; David L.B. Schwappach
2015-01-01
Background Compliance with surgical checklist use remains an obstacle in the context of checklist implementation programs. The theory of planned behaviour was applied to analyse attitudes, perceived behaviour control, and norms as psychological antecedents of individuals’ intentions to use the checklist. Methods A cross-sectional survey study with staff (N = 866) of 10 Swiss hospitals was conducted in German and French. Group mean differences between individuals with and without managerial fu...
Mascherek, Anna C; Gehring, Katrin; Bezzola, Paula; David L.B. Schwappach
2015-01-01
BACKGROUND Compliance with surgical checklist use remains an obstacle in the context of checklist implementation programs. The theory of planned behaviour was applied to analyse attitudes, perceived behaviour control, and norms as psychological antecedents of individuals' intentions to use the checklist. METHODS A cross-sectional survey study with staff (N = 866) of 10 Swiss hospitals was conducted in German and French. Group mean differences between individuals with and without m...
Neutron-capture cross sections from indirect measurements
Directory of Open Access Journals (Sweden)
Scielzo N.D.
2012-02-01
Full Text Available Cross sections for compound-nuclear reactions reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f reactions, but need to be improved upon for applications to capture reactions.
Neutron-capture Cross Sections from Indirect Measurements
Energy Technology Data Exchange (ETDEWEB)
Escher, J E; Burke, J T; Dietrich, F S; Ressler, J J; Scielzo, N D; Thompson, I J
2011-10-18
Cross sections for compound-nuclear reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f) reactions, but need to be improved upon for applications to capture reactions.
Nucleon-x sub c sub J dissociation cross sections
Feng You Ceng; Xu Xiao Ming
2002-01-01
Nucleon-x sub c sub J dissociation cross sections are calculated in a constituent inter-exchange model in which quark-quark potential is derived from the Buchmueller-Type quark-anti-quark potential. These new cross sections for dominant reaction channels depend on the centre-of-mass energy of the nucleon and the charmonium
Total Cross Sections at High Energies An update
Fazal-e-Aleem, M; Alam, Saeed; Qadee-Afzal, M
2002-01-01
Current and Future measurements for the total cross sections at E-811, PP2PP, CSM, FELIX and TOTEM have been analyzed using various models. In the light of this study an attempt has been made to focus on the behavior of total cross section at very high energies.
Heisenberg's Universal (lns)**2 Increase of Total Cross Sections
Dosch, H G; Nicolescu, Basarab
2003-01-01
The (lns)**2 behaviour of total cross-sections, first obtained by Heisenberg 50 years ago, receives now increased interest both on phenomenological and theoretical levels. In this paper we present a modification of the Heisenberg's model in connection with the presence of glueballs and we show that it leads to a realistic description of all existing hadron total cross-section data.
Cross-section measurements in the NOMAD experiment
Petti, R
2006-01-01
The NOMAD experiment collected valuable neutrino data samples, matching both the large statistics of massive calorimeters and the reconstruction quality of bubble chambers. This paper describes the recent measurements of neutrino cross-sections on carbon target. The approach followed for cross-section modeling is also explained.
Schramkowski, G.P.; De Swart, H.E.; Schuttelaars, H.M.
2009-01-01
A three-dimensional numerical model with a prognostic salinity field is used to investigate the effect of a partial slip bottom boundary condition on lateral flow and sediment distribution in a transect of a tidally dominated channel. The transect has a symmetrical Gaussian cross-channel bottom prof
Chehade, Wissam; Weber, Mark; Gorshelev, Victor; Serdyuchenko, Anna; Burrows, John P.
For a long term coverage of global O3 measurements from SCIAMACHY (SCanning Imag-ing Absorption spectroMeter for Atmospheric CHartographY), GOME1, and GOME2 (Global Ozone Monitoring Experiment), high quality absorption cross section spectra is a pre-requisite. Laboratory measurements of cross section spectra of O3 (at 203K, 223K, 243K, 273K and 293K) were performed using CATGAS (Calibration Apparatus for Trace Gas Absorption Spec-troscopy) under representative in-flight conditions with SCIAMACHY and GOME-2 spectrom-eters to obviate the need of an instrumental slit function correction. For the data acquired from the CATGAS campaigns, a re-analysis is carried out to improve the overestimation in the total O3 retrieval by SCIAMACHY and GOME2 using the flight model (FM) reference data from SCIAMACHY and GOME2, respectively, with respect to GOME1. The reanalysis attempts to re-evaluate the concatenation of ozone optical density measurements obtained from CATGAS measurements and applying new ways to absolutely calibrate the cross-.sections using absolute reference cross-section data at reference wavelengths, Finally, a satellite retrieval error analy-sis will be performed to validate the updated satellite reference cross-sections. The updated reference data can be used for combining the data from the three instruments (plus the two upcoming GOME-2) generating a consisting long-term dataset of total ozone.
Accurate, nonintrusive, and inexpensive techniques are needed to measure energy expenditure (EE) in free-living populations. Our primary aim in this study was to validate cross-sectional time series (CSTS) and multivariate adaptive regression splines (MARS) models based on observable participant cha...
DEFF Research Database (Denmark)
Pardo, D.; Branner, K.
2005-01-01
A very detailed 2D-solid finite element model is developed representing the load carrying box girder of a wind turbine blade. Using typical geometrical values for the girder dimensions and public available material data, the overall cross-sectional behaviour is analysed for a simple compressive...
Energy Technology Data Exchange (ETDEWEB)
Guasp, J.; Navarro, C.
1973-07-01
A FORTRAN V computer code for UNIVAC 1108/6 using a local Optical Model with spin-orbit interaction is described. The code calculates fast neutron cross sections, angular distribution, and Legendre moments for heavy and intermediate spherical nuclei. It allows for the possibility of automatic variation of potential parameters for experimental data fitting. (Author) 55 refs.
Dutta, Saumi; Bhattacharyya, Abhijit
2016-01-01
The neutron capture cross sections have been studied near the $Z=50$ closed shell for a number of nuclei those take part in heavy element nucleosynthesis, the slow and the rapid neutron capture processes and the proton capture process. An optical model potential is constructed in theoretical approach by folding the density dependent M3y purely real nucleon-nucleon interaction with the target radial matter density in relativistic mean field (RMF) approach. The standard code TALYS1.8 is used for cross-section calculation. We have presented the Maxwellian-averaged capture cross-section (MACS) values and stellar neutron capture reaction rates at astrophysically relevant thermal energies and temperatures.
Indian Academy of Sciences (India)
Sandhya Jain
2012-10-01
The measurement of the inclusive cross-section for $Z$ production at LHC with 7 TeV proton–proton collision is presented. The electron and muon decay modes are used to reconstruct the boson. The total cross-section is measured for photon transverse energy greater than 10 GeV and with photon and charged lepton separation in the pseudorapidity-azimuthal angle plane greater than 0.7. This study is extended by a measurement of $Z( \\bar{})$ cross-section. A search is performed for extra dimensions in the Arkani-Hamed, Dimopoulos, Dvali framework using the final state of a graviton and photon. The limits are extended with MD > 1.25–1.31 TeV for = 2-6. The measurement is found to be in agreement with the Standard Model prediction.
Differential cross sections of positron hydrogen collisions
Institute of Scientific and Technical Information of China (English)
于荣梅; 濮春英; 黄晓玉; 殷复荣; 刘旭焱; 焦利光; 周雅君
2016-01-01
We make a detailed study on the angular differential cross sections of positron–hydrogen collisions by using the momentum-space coupled-channels optical (CCO) method for incident energies below the H ionization threshold. The target continuum and the positronium (Ps) formation channels are included in the coupled-channels calculations via a complex equivalent-local optical potential. The critical points, which show minima in the differential cross sections, as a function of the scattering angle and the incident energy are investigated. The resonances in the angular differential cross sections are reported for the first time in this energy range. The effects of the target continuum and the Ps formation channels on the different cross sections are discussed.
A nuclear cross section data handbook
Energy Technology Data Exchange (ETDEWEB)
Fisher, H.O.M.
1989-12-01
Isotopic information, reaction data, data availability, heating numbers, and evaluation information are given for 129 neutron cross-section evaluations, which are the source of the default cross sections for the Monte Carlo code MCNP. Additionally, pie diagrams for each nuclide displaying the percent contribution of a given reaction to the total cross section are given at 14 MeV, 1 MeV, and thermal energy. Other information about the evaluations and their availability in continuous-energy, discrete-reaction, and multigroup forms is provided. The evaluations come from ENDF/B-V, ENDL85, and the Los Alamos Applied Nuclear Science Group T-2. Graphs of all neutron and photon production cross-section reactions for these nuclides have been categorized and plotted. 21 refs., 5 tabs.
Systematics of (n,2n) Cross Sections
Institute of Scientific and Technical Information of China (English)
2008-01-01
<正>The experimental data of (n, 2n) cross sections were collected and evaluated as complete as possible. There are 640 sets of experimental data for 130 nuclei. The data were fitted to the expressions that describe the
Neutron capture cross sections from Surrogate measurements
Directory of Open Access Journals (Sweden)
Scielzo N.D.
2010-03-01
Full Text Available The prospects for determining cross sections for compound-nuclear neutron-capture reactions from Surrogate measurements are investigated. Calculations as well as experimental results are presented that test the Weisskopf-Ewing approximation, which is employed in most analyses of Surrogate data. It is concluded that, in general, one has to go beyond this approximation in order to obtain (n,γ cross sections of sufficient accuracy for most astrophysical and nuclear-energy applications.
Modified Empirical Parametrization of Fragmentation Cross Sections
Sümmerer, K
2000-01-01
New experimental data obtained mainly at the GSI/FRS facility allow to modify the empirical parametrization of fragmentation cross sections, EPAX. It will be shown that minor modifications of the parameters lead to a much better reproduction of measured cross sections. The most significant changes refer to the description of fragmentation yields close to the projectile and of the memory effect of neutron-deficient projectiles.
Total cross sections for neutron scattering
Chinn, C. R.; Elster, Ch.; Thaler, R. M.; Weppner, S. P.
1995-02-01
Measurements of neutron total cross sections are both extensive and extremely accurate. Although they place a strong constraint on theoretically constructed models, there are relatively few comparisons of predictions with experiment. The total cross sections for neutron scattering from 16O and 40Ca are calculated as a function of energy from 50 to 700 MeV laboratory energy with a microscopic first-order optical potential derived within the framework of the Watson expansion. Although these results are aleady in qualitative agreement with the data, the inclusion of medium corrections to the propagator is essential to correctly predict the energy dependence given by the experiment. In the region between 100 and 200 MeV, where off-shell tρ calculations for both 16O and 40Ca overpredict the experiment, the modification due to the nuclear medium reduces the calculated values. Above 300 MeV these corrections are very small and depending on the employed nuclear mean field tend to compensate for the underprediction of the off-shell tρ results.
Total cross sections for neutron scattering
Energy Technology Data Exchange (ETDEWEB)
Chinn, C.R.; Elster, C.; Thaler, R.M.; Weppner, S.P. (Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States) Center for Computationally Intensive Physics, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States) Institute of Nuclear Particle Physics and Department of Physics, Ohio University, Athens, Ohio 45701 (United States) Physics Department, Case Western Reserve University, Cleveland, Ohio 44106 (United States))
1995-02-01
Measurements of neutron total cross sections are both extensive and extremely accurate. Although they place a strong constraint on theoretically constructed models, there are relatively few comparisons of predictions with experiment. The total cross sections for neutron scattering from [sup 16]O and [sup 40]Ca are calculated as a function of energy from 50 to 700 MeV laboratory energy with a microscopic first-order optical potential derived within the framework of the Watson expansion. Although these results are aleady in qualitative agreement with the data, the inclusion of medium corrections to the propagator is essential to correctly predict the energy dependence given by the experiment. In the region between 100 and 200 MeV, where off-shell [ital t][rho] calculations for both [sup 16]O and [sup 40]Ca overpredict the experiment, the modification due to the nuclear medium reduces the calculated values. Above 300 MeV these corrections are very small and depending on the employed nuclear mean field tend to compensate for the underprediction of the off-shell [ital t][rho] results.
Applications of the BEam Cross section Analysis Software (BECAS)
DEFF Research Database (Denmark)
Blasques, José Pedro Albergaria Amaral; Bitsche, Robert; Fedorov, Vladimir;
2013-01-01
A newly developed framework is presented for structural design and analysis of long slender beam-like structures, e.g., wind turbine blades. The framework is based on the BEam Cross section Analysis Software – BECAS – a finite element based cross section analysis tool. BECAS is used for the gener......A newly developed framework is presented for structural design and analysis of long slender beam-like structures, e.g., wind turbine blades. The framework is based on the BEam Cross section Analysis Software – BECAS – a finite element based cross section analysis tool. BECAS is used...... for the generation of beam finite element models which correctly account for effects stemming from material anisotropy and inhomogeneity in cross sections of arbitrary geometry. These type of modelling approach allows for an accurate yet computationally inexpensive representation of a general class of three...
2014-09-26
ensures the vanishing of 8coh’ unless the Snell angle (aox = aoy = 0) is chosen.] Note that this coherent-scatter cross section depends on the area...Bistatic at the Snell Angle (R T): L 0 6ioR)x = (1oT)x when oT = ’/2 = ( oR - i/2); ) when =(R +R )sin Snell (A.2-14a) R)y = oT)y whe oT + oR) s oT
Guarini, E
2003-01-01
A review of the available tools for the calculation of the neutron double-differential cross-section of fundamental molecules, such as hydrogen and methane, is reported here. The most common cases occurring in neutron data analysis are treated in detail with the aim of providing the reader with intelligible and efficient procedures. The utility nowadays of these kinds of computation are widely described, and applications discussed, with examples based on the comparison with experimental data. New advances and refinement/corrections of earlier work are given throughout the paper, as well as suggestions for practical implementation. (topical review)
Arnold, C W; Karwowski, H J; Rich, G C; Tompkins, J R; Howell, C R
2010-01-01
A neutron counter designed for assay of radioactive materials has been adapted for beam experiments at TUNL. The cylindrical geometry and 64% maximum efficiency make it well suited for ($\\gamma,n$) cross-section measurements near the neutron emission threshold. A high precision characterization of the counter has been made using neutrons from several sources. Using a combination of measurements and simulations, the absolute detection efficiency of the neutron counter was determined to an accuracy of $\\pm$ 3% in the neutron energy range between 0.1 and 1 MeV. It is shown that this efficiency characterization is generally valid for a wide range of targets.
Energy Technology Data Exchange (ETDEWEB)
Huo, Winifred M. [NASA Ames Research Center, Mail Stop T27B-1, Moffett Field, CA 94035-1000 (United States)]. E-mail: whuo@mail.arc.nasa.gov; Dateo, Christopher E. [ELORET Corporation, Sunnyvale, CA (United States); Fletcher, Graham D. [ELORET Corporation, Sunnyvale, CA (United States)
2006-10-15
As part of the database for building up a biochemical model of DNA radiation damage, electron impact ionization cross sections of sugar-phosphate backbone and DNA bases have been calculated using the improved binary-encounter dipole (iBED) model. It is found that the total ionization cross sections of C{sub 3}{sup '}- and C{sub 5}{sup '}-deoxyribose-phosphate, two conformers of the sugar-phosphate backbone, are close to each other. Furthermore, the sum of the ionization cross sections of the separate deoxyribose and phosphate fragments is in close agreement with the C{sub 3}{sup '}- and C{sub 5}{sup '}-deoxyribose-phosphate cross sections, differing by less than 10%, an indication that a building-up principle may be applicable. Of the four DNA bases, the ionization cross section of guanine is the largest, then in decreasing order, adenine, thymine, and cytosine. The order is in accordance with the known propensity of oxidation of the bases by ionizing radiation. Dissociative ionization (DI), a process that both ionizes and dissociates a molecule, is investigated for cytosine. The DI cross section for the formation of H and (cytosine-H1){sup +}, with the cytosine ion losing H at the 1 position, is also reported. The threshold of this process is calculated to be 16.9eV. Detailed analysis of ionization products such as in DI is important to trace the sequential steps in the biochemical process of DNA damage.
Tel, E.; Durgu, C.; Aydın, A.; Bölükdemir, M. H.; Kaplan, A.; Okuducu, Ş.
2009-12-01
In the next century the world will face the need for new energy sources. Nuclear fusion can be one of the most attractive sources of energy from the viewpoint of safety and minimal environmental impact. Fusion will not produce CO2 or SO2 and thus will not contribute to global warming or acid rain. Achieving acceptable performance for a fusion power system in the areas of economics, safety and environmental acceptability, is critically dependent on performance of the blanket and diverter systems which are the primary heat recovery, plasma purification, and tritium breeding systems. Tritium self-sufficiency must be maintained for a commercial power plant. The hybrid reactor is a combination of the fusion and fission processes. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So working out the systematics of ( n, t) reaction cross-sections are of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at energies up to 20 MeV. In this study, we have calculated non-elastic cross-sections by using optical model for ( n, t) reactions at 14-15 MeV energy. We have investigated the excitation function character and reaction Q-values depending on the asymmetry term effect for the ( n, t) reaction cross-sections. We have obtained new coefficients for the ( n, t) reaction cross-sections. We have suggested semi-empirical formulas including optical model nonelastic effects by fitting two parameters for the ( n, t) reaction cross-sections at 14-15 MeV. We have discussed the odd-even effect and the pairing effect considering binding energy systematic of the nuclear shell model for the new experimental data and new cross-sections formulas ( n, t) reactions developed by Tel et al. We have determined a different parameter groups by the classification of nuclei into even-even, even-odd and odd-even for ( n, t) reactions cross-sections. The obtained cross-section formulas
Evaluation of neutron cross sections for Er isotopes
Energy Technology Data Exchange (ETDEWEB)
Harun-ar-Rashid, A.K.M. [Univ. of Chittagong, Department of Physics, Chittagong (Bangladesh); Shibata, K. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Igashira, M. [Tokyo Inst. of Technology, Research Laboratory for Nuclear Reactors, Tokyo (Japan)
2001-03-01
The neutron reaction cross sections of {sup 166,167,168,170}Er from 10{sup -5} eV to 20 MeV were studied. The cross sections were calculated with a variety of nuclear-reaction models by different codes. The calculations were mainly based on the statistical and optical modes. In the calculation, the Optical Model Parameters (OMP) for {sup nat}Er were determined. The calculated capture cross sections are in good agreement with the very recent measurements. The calculated total cross sections of {sup 166,168,170}Er are also in good agreement with the experimental results at 14 MeV. The direct inelastic scattering cross sections for the first excited state of the above nuclei were calculated by Distorted-Wave Born-Approximation (DWBA). The direct and semi-direct (DSD) capture cross sections were also calculated. The pre-equilibrium correction was done. The parameters for the electric-dipole pygmy resonance and the depression factor were extracted from a comparison between the calculated and very recent observed capture gamma-ray spectra. The other cross sections, such as (n,n'), (n,2n) and (n,p) reactions and, the emitted-particle (n,p,d,etc.) spectra from these reactions were also calculated. In the thermal and resonance region, the total, elastic scattering and capture cross sections were derived from the resonance parameters. (author)
Chopra, Sahila; Kaur, Arshdeep; Hemdeep, Gupta, Raj K.
2016-04-01
The product PCNPsurv of compound nucleus (CN) fusion probability PCN and survival probability Psurv is calculated to determine the reduced evaporation residue cross section σER/σfusion , denoted σERreduced, with (total) fusion cross section σfusion given as a sum of CN-formation cross section σCN and non-CN cross section σnCN for each reaction, where σCN is the sum of evaporation residue cross section σER and fusion-fission cross section σff and σnCN, if not measured, is estimated empirically as the difference between measured and calculated σfusion. Our calculations of PCN and Psurv, based on the dynamical cluster-decay model, were successfully made for some 17 "hot" fusion reactions, forming different CN of mass numbers ACN˜100 -300 , with deformations of nuclei up to hexadecapole deformations and "compact" orientations for both coplanar (Φc=0∘ ) and noncoplanar (Φc≠0∘ ) configurations, using various different nuclear interaction potentials. Interesting variations of σERreduced with CN excitation energy E*, fissility parameter χ , CN mass ACN, and Coulomb parameter Z1Z2 show that, independent of entrance channel, different isotopes of CN, and nuclear interaction potentials used, the dominant quantity in the product is Psurv, which classifies all the studied CN into three groups of weakly fissioning, radioactive, and strongly fissioning superheavy nuclei, with relative magnitudes of σERreduced˜1 , ˜10-6 , and ˜10-11 , which, like for PCN, get further grouped in two dependencies of (i) weakly fissioning and strongly fissioning superheavy nuclei decreasing with increasing E* and (ii) radioactive nuclei increasing with increasing E*.
Anderson, Daniel
2012-01-01
This manuscript provides an overview of hierarchical linear modeling (HLM), as part of a series of papers covering topics relevant to consumers of educational research. HLM is tremendously flexible, allowing researchers to specify relations across multiple "levels" of the educational system (e.g., students, classrooms, schools, etc.).…
Directory of Open Access Journals (Sweden)
Arnulfo Luévanos Rojas
2014-07-01
Full Text Available This paper develops a mathematical model for fixed-end moments for two different types of loads on beams with a parabolic shaped variable rectangular cross section. The loads applied on beam are: 1 a uniformly distributed load and 2 a concentrated load located anywhere along the beam length. The properties of the rectangular cross section of the beam varies along its axis, i.e., the width “b” is constant and the height “h” varies along the beam, this variation follows a parabolic form. The consistent deformation method based on the superposition of the effects is used to solve these problems. The deformation anywhere along the beam is obtained by using the Bernoulli-Euler theory. Traditional methods used to obtain deflections of variable cross section members are any techniques that perform numerical integration, such as Simpson's rule. Tables presented by other authors are restricted to certain relationships. Beyond the effectiveness and accuracy of the developed model, a significant advantage of it is the moments are calculated at any cross section of the beam using the respective integral representations as mathematical formulas.
Hallquist, Michael N; Wright, Aidan G C
2014-01-01
Over the past 75 years, the study of personality and personality disorders has been informed considerably by an impressive array of psychometric instruments. Many of these tests draw on the perspective that personality features can be conceptualized in terms of latent traits that vary dimensionally across the population. A purely trait-oriented approach to personality, however, might overlook heterogeneity that is related to similarities among subgroups of people. This article describes how factor mixture modeling (FMM), which incorporates both categories and dimensions, can be used to represent person-oriented and trait-oriented variability in the latent structure of personality. We provide an overview of different forms of FMM that vary in the degree to which they emphasize trait- versus person-oriented variability. We also provide practical guidelines for applying FMM to personality data, and we illustrate model fitting and interpretation using an empirical analysis of general personality dysfunction.
Temperature-dependent absorption cross sections for hydrogen peroxide vapor
Nicovich, J. M.; Wine, P. H.
1988-03-01
Relative absorption cross sections for hydrogen peroxide vapor were measured over the temperature ranges 285-381 K for lambda = 230 nm-295 nm and 300-381 K for lambda = 193 nm-350 nm. The well established 298 K cross sections at 202.6 and 228.8 nm were used as an absolute calibration. A significant temperature dependence was observed at the important tropospheric photolysis wavelengths lambda over 300 nm. Measured cross sections were extrapolated to lower temperatures, using a simple model which attributes the observed temperature dependence to enhanced absorption by molecules possessing one quantum of O-O stretch vibrational excitation. Upper tropospheric photodissociation rates calculated using the extrapolated cross sections are about 25 percent lower than those calculated using currently recommended 298 K cross sections.
Hadronic cross sections, elastic slope and physical bounds
Energy Technology Data Exchange (ETDEWEB)
Fagundes, D. A.; Menon, M. J. [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP, 13083-859 Campinas SP (Brazil)
2013-03-25
An almost model-independent parametrization for the ratio of the total hadronic cross section to elastic slope is discussed. Its applicability in studies of asymptotia and analyses of extensive air shower in cosmic-ray physics is also outlined.
Hadronic Cross Sections, Elastic Slope and Physical Bounds
Fagundes, D A
2012-01-01
An almost model-independent parametrization for the ratio of the total hadronic cross section to elastic slope is discussed. Its applicability in studies of asymptotia and analyses of extensive air shower in cosmic-ray physics is also outlined.
Top quark production cross-section measurements
Suzuki, Shota; The ATLAS collaboration
2017-01-01
Measurements of the inclusive and differential cross-sections for top-quark pair and single top production cross sections in proton-proton collisions with the ATLAS detector at the Large Hadron Collider are presented at center-of-mass energies of 8 TeV and 13 TeV. The inclusive measurements reach high precision and are compared to the best available theoretical calculations. These measurements, including results using boosted tops, probe our understanding of top-pair production in the TeV regime. The results are compared to Monte Carlo generators implementing LO and NLO matrix elements matched with parton showers and NLO QCD calculations. For the t-channel single top measurement, the single top-quark and anti-top-quark total production cross-sections, their ratio, as well as differential cross sections are also presented. A measurement of the production cross-section of a single top quark in association with a W boson, the second largest single-top production mode, is also presented. Finally, measurements of ...
Reduction Methods for Total Reaction Cross Sections
Gomes, P. R. S.; Mendes Junior, D. R.; Canto, L. F.; Lubian, J.; de Faria, P. N.
2016-03-01
The most frequently used methods to reduce fusion and total reaction excitation functions were investigated in a very recent paper Canto et al. (Phys Rev C 92:014626, 2015). These methods are widely used to eliminate the influence of masses and charges in comparisons of cross sections for weakly bound and tightly bound systems. This study reached two main conclusions. The first is that the fusion function method is the most successful procedure to reduce fusion cross sections. Applying this method to theoretical cross sections of single channel calculations, one obtains a system independent curve (the fusion function), that can be used as a benchmark to fusion data. The second conclusion was that none of the reduction methods available in the literature is able to provide a universal curve for total reaction cross sections. The reduced single channel cross sections keep a strong dependence of the atomic and mass numbers of the collision partners, except for systems in the same mass range. In the present work we pursue this problem further, applying the reduction methods to systems within a limited mass range. We show that, under these circumstances, the reduction of reaction data may be very useful.
Togano, Yasuhiro; Samurai Collaboration
2014-09-01
Reaction cross section of 22C on a carbon target at an energy of 240 MeV/nucleon have been measured by using the transmission method. The most neutron-rich carbon isotopes 22C is a candidate of a two-neutron halo nucleus. Tanaka et al. [1] measured the reaction cross section of 22C on a hydrogen target at 40 MeV/nucleon. It is showed 22C to have a large matter radius of 5 . 9 +/- 0 . 9 fm, which is much larger than the ones of carbon isotopes with N SAMURAI spectrometer at RIBF. The 22C beam at 240 MeV/nucleon was impinged on a carbon target, and the reaction product was identified by using SAMURAI spectrometer. In the present talk, the extracted reaction cross section and derived matter density distribution of 22C will be presented.
Dijet cross sections in photoproduction at HERA
Derrick, Malcolm; Magill, S; Mikunas, D; Musgrave, B; Repond, J; Stanek, R; Talaga, R L; Zhang, H; Ayad, R; Bari, G; Basile, M; Bellagamba, L; Boscherini, D; Bruni, A; Bruni, G; Bruni, P; Cara Romeo, G; Castellini, G; Chiarini, M; Cifarelli, Luisa; Cindolo, F; Contin, A; Corradi, M; Gialas, I; Giusti, P; Iacobucci, G; Laurenti, G; Levi, G; Margotti, A; Massam, Thomas; Nania, R; Nemoz, C; Palmonari, F; Polini, A; Sartorelli, G; Timellini, R; Zamora-Garcia, Yu E; Zichichi, Antonino; Bargende, A; Crittenden, James Arthur; Desch, Klaus; Diekmann, B; Doeker, T; Eckert, M; Feld, L; Frey, A; Geerts, M; Geitz, G; Grothe, M; Haas, T; Hartmann, H; Haun, D; Heinloth, K; Hilger, E; Jakob, H P; Katz, U F; Mari, S M; Mass, A; Mengel, S; Mollen, J; Paul, E; Rembser, C; Schattevoy, R; Schramm, D; Stamm, J; Wedemeyer, R; Campbell-Robson, S; Cassidy, A; Dyce, N; Foster, B; George, S; Gilmore, R; Heath, G P; Heath, H F; Llewellyn, T J; Morgado, C J S; Norman, D J P; O'Mara, J A; Tapper, R J; Wilson, S S; Yoshida, R; Rau, R R; Arneodo, M; Iannotti, L; Schioppa, M; Susinno, G; Bernstein, A M; Caldwell, A; Cartiglia, N; Parsons, J A; Ritz, S; Sciulli, F; Straub, P B; Wai, L; Yang, S; Zhu, Q; Borzemski, P; Chwastowski, J; Eskreys, Andrzej; Piotrzkowski, K; Zachara, M; Zawiejski, L; Adamczyk, L; Bednarek, B; Jelen, K; Kisielewska, D; Kowalski, T; Rulikowska-Zarebska, E; Suszycki, L; Zajac, J; Kotanski, Andrzej; Przybycien, M B; Bauerdick, L A T; Behrens, U; Beier, H; Bienlein, J K; Coldewey, C; Deppe, O; Desler, K; Drews, G; Flasinski, M; Gilkinson, D J; Glasman, C; Göttlicher, P; Grosse-Knetter, J; Gutjahr, B; Hain, W; Hasell, D; Hessling, H; Hultschig, H; Iga, Y; Joos, P; Kasemann, M; Klanner, Robert; Koch, W; Köpke, L; Kötz, U; Kowalski, H; Labs, J; Ladage, A; Löhr, B; Loewe, M; Lüke, D; Manczak, O; Ng, J S T; Nickel, S; Notz, D; Ohrenberg, K; Roco, M T; Rohde, M; Roldán, J; Schneekloth, U; Schulz, W; Selonke, F; Stiliaris, E; Surrow, B; Voss, T; Westphal, D; Wolf, G; Youngman, C; Zhou, J F; Grabosch, H J; Kharchilava, A I; Leich, A; Mattingly, M C K; Meyer, A; Schlenstedt, S; Wulff, N; Barbagli, G; Pelfer, P G; Anzivino, Giuseppina; Maccarrone, G D; De Pasquale, S; Votano, L; Bamberger, Andreas; Eisenhardt, S; Freidhof, A; Söldner-Rembold, S; Schröder, J; Trefzger, T M; Brook, N H; Bussey, Peter J; Doyle, A T; Fleck, I; Saxon, D H; Utley, M L; Wilson, A S; Dannemann, A; Holm, U; Horstmann, D; Neumann, T; Sinkus, R; Wick, K; Badura, E; Burow, B D; Hagge, L; Lohrmann, E; Mainusch, J; Milewski, J; Nakahata, M; Pavel, N; Poelz, G; Schott, W; Zetsche, F; Bacon, Trevor C; Butterworth, Ian; Gallo, E; Harris, V L; Hung, B Y H; Long, K R; Miller, D B; Morawitz, P P O; Prinias, A; Sedgbeer, J K; Whitfield, A F; Mallik, U; McCliment, E; Wang, M Z; Wang, S M; Wu, J T; Zhang, Y; Cloth, P; Filges, D; An Shiz Hong; Hong, S M; Nam, S W; Park, S K; Suh, M H; Yon, S H; Imlay, R; Kartik, S; Kim, H J; McNeil, R R; Metcalf, W; Nadendla, V K; Barreiro, F; Cases, G; Graciani, R; Hernández, J M; Hervás, L; Labarga, L; Del Peso, J; Puga, J; Terrón, J; De Trocóniz, J F; Smith, G R; Corriveau, F; Hanna, D S; Hartmann, J; Hung, L W; Lim, J N; Matthews, C G; Patel, P M; Sinclair, L E; Stairs, D G; Saint-Laurent, M G; Ullmann, R T; Zacek, G; Bashkirov, V; Dolgoshein, B A; Stifutkin, A; Bashindzhagian, G L; Ermolov, P F; Gladilin, L K; Golubkov, Yu A; Kobrin, V D; Kuzmin, V A; Proskuryakov, A S; Savin, A A; Shcheglova, L M; Solomin, A N; Zotov, N P; Botje, M; Chlebana, F S; Dake, A P; Engelen, J; De Kamps, M; Kooijman, P M; Kruse, A; Tiecke, H G; Verkerke, W; Vreeswijk, M; Wiggers, L; De Wolf, E; Van Woudenberg, R; Acosta, D; Bylsma, B G; Durkin, L S; Honscheid, K; Li Chuan; Ling, T Y; McLean, K W; Murray, W N; Park, I H; Romanowsky, T A; Seidlein, R; Bailey, D S; Blair, G A; Byrne, A; Cashmore, Roger J; Cooper-Sarkar, A M; Daniels, D C; Devenish, R C E; Harnew, N; Lancaster, M; Luffman, P; Lindemann, L; McFall, J D; Nath, C; Noyes, V A; Quadt, A; Uijterwaal, H; Walczak, R; Wilson, F F; Yip, T; Abbiendi, G; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; De Giorgi, M; Dosselli, U; Limentani, S; Morandin, M; Posocco, M; Stanco, L; Stroili, R; Voci, C; Bulmahn, J; Butterworth, J M; Feild, R G; Oh, B Y; Whitmore, J; D'Agostini, Giulio; Marini, G; Nigro, A; Tassi, E; Hart, J C; McCubbin, N A; Prytz, K; Shah, T P; Short, T L; Barberis, E; Dubbs, T; Heusch, C A; Van Hook, M; Hubbard, B; Lockman, W; Rahn, J T; Sadrozinski, H F W; Seiden, A; Biltzinger, J; Seifert, R J; Walenta, Albert H; Zech, G; Abramowicz, H; Briskin, G M; Dagan, S; Levy, A; Hasegawa, T; Hazumi, M; Ishii, T; Kuze, M; Mine, S; Nagasawa, Y; Nakao, M; Susuki, I; Tokushuku, K; Yamada, S; Yamazaki, Y; Chiba, M; Hamatsu, R; Hirose, T; Homma, K; Kitamura, S; Nakamitsu, Y; Yamauchi, K; Cirio, R; Costa, M; Ferrero, M I; Lamberti, L; Maselli, S; Peroni, C; Sacchi, R; Solano, A; Staiano, A; Dardo, M; Bailey, D C; Bandyopadhyay, D; Bénard, F; Brkic, M; Crombie, M B; Gingrich, D M; Hartner, G F; Joo, K K; Levman, G M; Martin, J F; Orr, R S; Sampson, C R; Teuscher, R; Catterall, C D; Jones, T W; Kaziewicz, P B; Lane, J B; Saunders, R L; Shulman, J; Blankenship, K; Kochocki, J A; Lu, B; Mo, L W; Bogusz, W; Charchula, K; Ciborowski, J; Gajewski, J; Grzelak, G; Kasprzak, M; Krzyzanowski, M; Muchorowski, K; Nowak, R J; Pawlak, J M; Tymieniecka, T; Wróblewski, A K; Zakrzewski, J A; Zarnecki, A F; Adamus, M; Eisenberg, Y; Karshon, U; Revel, D; Zer-Zion, D; Ali, I; Badgett, W F; Behrens, B H; Dasu, S; Fordham, C; Foudas, C; Goussiou, A; Loveless, R J; Reeder, D D; Silverstein, S; Smith, W H; Vaiciulis, A W; Wodarczyk, M; Tsurugai, T; Bhadra, S; Cardy, M L; Fagerstroem, C P; Frisken, W R; Furutani, K M; Khakzad, M; Schmidke, W B; Levy, A
1995-01-01
Dijet production by almost real photons has been studied at HERA with the ZEUS detector. Jets have been identified using the cone algorithm. A cut on xg, the fraction of the photon energy participating in the production of the two jets of highest transverse energy, is used to define cross sections sensitive to the parton distributions in the proton and in the photon. The dependence of the dijet cross sections on pseudorapidity has been measured for xg \\ge 0.75 and xg < 0.75. The former is sensitive to the gluon momentum density in the proton. The latter is sensitive to the gluon in the photon. The cross sections are corrected for detector acceptance and compared to leading order QCD calculations.
First measurement of unpolarized SIDIS cross section and cross section ratios from a $^3$He target
Yan, X; Aniol, K; Annand, J R M; Averett, T; Benmokhtar, F; Bertozzi, W; Bradshaw, P C; Bosted, P; Camsonne, A; Canan, M; Cates, G D; Chen, C; Chen, J -P; Chen, W; Chirapatpimol, K; Chudakov, E; Cisbani, E; Cornejo, J C; Cusanno, F; Dalton, M M; Deconinck, W; de Jager, C W; De Leo, R; Deng, X; Deur, A; Ding, H; Dolph, P A M; Dutta, C; Dutta, D; Fassi, L El; Frullani, S; Gao, H; Garibaldi, F; Gaskell, D; Gilad, S; Gilman, R; Glamazdin, O; Golge, S; Guo, L; Hamilton, D; Hansen, O; Higinbotham, D W; Holmstrom, T; Huang, J; Huang, M; Ibrahim, H F; Iodice, M; Jiang, X; Jin, G; Jones, M K; Katich, J; Kelleher, A; Kim, W; Kolarkar, A; Korsch, W; LeRose, J J; Li, X; Li, Y; Lindgren, R; Liu, T; Liyanage, N; Long, E; Lu, H -J; Margaziotis, D J; Markowitz, P; Marrone, S; McNulty, D; Meziani, Z -E; Michaels, R; Moffit, B; Camacho, C Munoz; Nanda, S; Narayan, A; Nelyubin, V; Norum, B; Oh, Y; Osipenko, M; Parno, D; Peng, J -C; Phillips, S K; Posik, M; Puckett, A J R; Qian, X; Qiang, Y; Rakhman, A; Ransome, R; Riordan, S; Saha, A; Sawatzky, B; Schulte, E; Shahinyan, A; Shabestari, M H; Sirca, S; Stepanyan, S; Subedi, R; Sulkosky, V; Tang, L -G; Tobias, W A; Urciuoli, G M; Vilardi, I; Wang, K; Wojtsekhowski, B; Wang, Y; Yan, X; Yao, H; Ye, Y; Ye, Z; Yuan, L; Zhan, X; Zhang, Y; Zhang, Y -W; Zhao, B; Zhao, Y X; Zheng, X; Zhu, L; Zhu, X; Zong, X
2016-01-01
The unpolarized semi-inclusive deep-inelastic scattering (SIDIS) differential cross sections in $^3$He($e,e^{\\prime}\\pi^{\\pm}$)$X$ have been measured for the first time in Jefferson Lab experiment E06-010 performed with a $5.9\\,$GeV $e^-$ beam on a $^3$He target. The experiment focuses on the valence quark region, covering a kinematic range $0.12 < x_{bj} < 0.45$, $1 < Q^2 < 4 \\, \\textrm{(GeV/c)}^2$, $0.45 < z_{h} < 0.65$, and $0.05 < P_t < 0.55 \\, \\textrm{GeV/c}$. The extracted SIDIS differential cross sections of $\\pi^{\\pm}$ production are compared with existing phenomenological models while the $^3$He nucleus approximated as two protons and one neutron in a plane wave picture, in multi-dimensional bins. Within the experimental uncertainties, the azimuthal modulations of the cross sections are found to be consistent with zero.
Top Quark Production Cross Section Measurements
Massa, Lorenzo; The ATLAS collaboration
2017-01-01
Measurements of the inclusive and diﬀerential cross-sections for top-quark pair and single top production cross sectionsinproton-proton collisions with the ATLAS detector at the Large Hadron Collider are presented at centre of mass energies of 8 TeV and 13 TeV. The inclusive measurements reach high precision and are compared to the best available theoretical calculations. These measurements, including results using boosted tops, probe our understanding of top-pair production in the TeV regime. The results are compared to Monte Carlo generators implementing LO and NLO matrix elements matched with parton showers and NLO QCD calculations. For the t-channel single top measurement, the single top-quark and anti-top-quark total production cross-sections, their ratio, as well as diﬀerential cross sections are also presented. A measurement of the production cross section of a single top quark in association witha W boson, the second largest single-top production mode, is also presented. Finally, measurements of t...
Electron impact rotationally elastic total cross section for formamide
Energy Technology Data Exchange (ETDEWEB)
Vinodkumar, Minaxi, E-mail: minaxivinod@yahoo.co.in [V P and R P T P Science College, Vallabh Vidyanagar 388120 (India); Limbachiya, Chetan, E-mail: chetanlimbachiya2@yahoo.com [Department of Applied Physics, The M.S. University of Baroda, Vadodara 390001 (India); Desai, Hardik, E-mail: hardikdesai.phy@gmail.com; Vinodkumar, P. C., E-mail: p.c.vinodkumar@gmail.com [Department of Physics, Sardar Patel University, Vallabh Vidyanagar 388120 (India)
2014-09-28
This paper reports computational results of the total cross sections for electron impact on formamide (HCONH₂) over a wide range of energies from 0.01 eV to 5 keV. Total cross sections over such a wide range are reported for the first time as the earlier reported data is up to maximum of 12 eV. Below ionization threshold of the target, we performed ab initio calculations using UK molecular R-Matrix code within static, exchange plus polarization (SEP), and close coupling approximations. Twenty eight target states are included in close coupling formalism. Total 350 channels and 2410 configuration state functions are included in the calculations. We observe a π* shape resonance at 3.41 eV and a σ* resonance at 15.3 eV as against similar resonances reported at 3.77 eV and 14.9 eV, respectively, by Goumans et al. [J. Chem. Theory Comput. 5, 217 (2009)] using SEP model. The cross sections at higher energies are evaluated using the spherical complex optical potential formalism. The two methods are found to be consistent with a smooth cross over at 18 eV. The vertical excitation energies, electronic excitation cross sections, differential cross sections, momentum transfer, and total cross sections are computed. In absence of experimental data, we compared our computed total cross sections with available other theoretical results.
The hadronic cross section measurement at KLOE
Energy Technology Data Exchange (ETDEWEB)
Aloisio, A.; Ambrosino, F.; Antonelli, A.; Antonelli, M.; Bacci, C.; Barva, M.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocci, V.; Bossi, F.; Branchini, P.; Bulychjov, S.A.; Caloi, R.; Campana, P.; Capon, G.; Capussela, T.; Carboni, G.; Ceradini, F.; Cervelli, F.; Cevenini, F.; Chiefari, G.; Ciambrone, P.; Conetti, S.; De Lucia, E.; De Santis, A.; De Simone, P.; De Zorzi, G.; Dell' Agnello, S.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Falco, S.; Di Micco, B.; Doria, A.; Dreucci, M.; Erriquez, O.; Farilla, A.; Felici, G.; Ferrari, A.; Ferrer, M.L.; Finocchiaro, G.; Forti, C.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Gorini, E.; Graziani, E.; Incagli, M.; Kluge, W.; Kulikov, V.; Lacava, F.; Lanfranchi, G.; Lee-Franzini, J.; Leone, D. [Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe Postfach 3640, D-76021 Karlsruhe (Germany); Lu, F.; Martemianov, M.; Martini, M.; Matsyuk, M.; Mei, W.; Merola, L.; Messi, R.; Miscetti, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nguyen, F.; Palutan, M.; Pasqualucci, E.; Passalacqua, L.; Passeri, A.; Patera, V.; Perfetto, F.; Petrolo, E.; Pontecorvo, L.; Primavera, M.; Santangelo, P.; Santovetti, E.; Saracino, G.; Schamberger, R.D.; Sciascia, B.; Sciubba, A.; Scuri, F.; Sfiligoi, I.; Sibidanov, A.; Spadaro, T.; Spiriti, E.; Tabidze, M.; Testa, M.; Tortora, L.; Valente, P.; Valeriani, B.; Venanzoni, G.; Veneziano, S.; Ventura, A.; Versaci, R.; Villella, I.; Xu, G
2005-07-15
KLOE uses the radiative return to measure cross section {sigma}(e{sup +}e{sup -}->{pi}{sup +}{pi}{sup -}{gamma}) at the electron-positron collider DA{phi}NE. Divinding by a theoretical radiator function, we obtain the cross section {sigma}(e{sup +}e{sup -}->{pi}{sup +}{pi}{sup -}{gamma}) for the mass range 0.35
Covariance Evaluation Methodology for Neutron Cross Sections
Energy Technology Data Exchange (ETDEWEB)
Herman,M.; Arcilla, R.; Mattoon, C.M.; Mughabghab, S.F.; Oblozinsky, P.; Pigni, M.; Pritychenko, b.; Songzoni, A.A.
2008-09-01
We present the NNDC-BNL methodology for estimating neutron cross section covariances in thermal, resolved resonance, unresolved resonance and fast neutron regions. The three key elements of the methodology are Atlas of Neutron Resonances, nuclear reaction code EMPIRE, and the Bayesian code implementing Kalman filter concept. The covariance data processing, visualization and distribution capabilities are integral components of the NNDC methodology. We illustrate its application on examples including relatively detailed evaluation of covariances for two individual nuclei and massive production of simple covariance estimates for 307 materials. Certain peculiarities regarding evaluation of covariances for resolved resonances and the consistency between resonance parameter uncertainties and thermal cross section uncertainties are also discussed.
Neutron capture cross section of Am241
Jandel, M.; Bredeweg, T. A.; Bond, E. M.; Chadwick, M. B.; Clement, R. R.; Couture, A.; O'Donnell, J. M.; Haight, R. C.; Kawano, T.; Reifarth, R.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.; Agvaanluvsan, U.; Parker, W. E.; Wu, C. Y.; Becker, J. A.
2008-09-01
The neutron capture cross section of Am241 for incident neutrons from 0.02 eV to 320 keV has been measured with the detector for advanced neutron capture experiments (DANCE) at the Los Alamos Neutron Science Center. The thermal neutron capture cross section was determined to be 665±33 b. Our result is in good agreement with other recent measurements. Resonance parameters for Enwell with the measured data, and the extracted averaged resonance parameters in the unresolved resonance region are consistent with those for the resolved resonances.
Neutron Capture Cross Section of 239Pu
Mosby, S.; Arnold, C.; Bredeweg, T. A.; Couture, A.; Jandel, M.; O'Donnell, J. M.; Rusev, G.; Ullmann, J. L.; Chyzh, A.; Henderson, R.; Kwan, E.; Wu, C. Y.
2014-09-01
The 239Pu(n,γ) cross section has been measured over the energy range 10 eV - 10 keV using the Detector for Advanced Neutron Capture Experiments (DANCE) as part of a campaign to produce precision (n,γ) measurements on 239Pu in the keV region. Fission coincidences were measured with a PPAC and used to characterize the prompt fission γ-ray spectrum in this region. The resulting spectra will be used to better characterize the fission component of another experiment with a thicker target to extend the (n,γ) cross section measurement well into the keV region.
Cross section data for ionization of important cyanides
Energy Technology Data Exchange (ETDEWEB)
Kaur, Jaspreet; Antony, Bobby, E-mail: bka.ism@gmail.com
2015-11-15
Highlights: • Multi centre spherical complex optical potential formalism used to find the CS. • Effective method (CSP-ic) to derive ionization contribution from inelastic CS. • Result shows excellent accord with previous results and consistent behaviour. • Maiden attempt to find CS for many cyanide molecules. • Strong correlation observed between peak of ionization with target properties. - Abstract: This article presents cross section calculations for interactions of important cyanides with electrons possessing energies beginning from ionization threshold of the target molecule to 5 keV. These data are pursued to meet the ever increasing demand for cross sections by the relevant atomic and molecular community for modelling astrophysical, atmospheric and technological domains. The calculations have been executed using an amalgam of multi centre spherical complex optical potential (MSCOP) formalism and complex scattering potential-ionization contribution (CSP-ic) method. Cross sections are compared with experimental and theoretical data wherever available. Strong correlations are observed for the cross sections which affirms consistent and reliable cross sections. Isomeric effect has been interpreted using variation of cross section with structure and target properties. Our cross sections will be tabulated in atomic collision database for use in modelling various statistical and dynamical quantities.
Asfahani, Jamal
2017-05-01
Fractal theory modeling technique is newly proposed in this research for interpreting the combination of nuclear well logging, including natural gamma ray, density and neutron-porosity, and the electrical well logging of long and short normal, for establishing the lithological cross section in basaltic environments. The logging data of Kodana well, localized in Southern Syria are used for testing and applying the proposed technique. The established cross section clearly shows the distribution and the identification of four kinds of basalt which are hard massive basalt, hard basalt, pyroclastic basalt and the alteration basalt products, clay. The concentration- Number (C-N) fractal modeling technique is successfully applied on the Kodana well logging data in southern Syria, and can be used efficiently when several wells with much well logging data with a high number of variables are required to be interpreted.
Barghouty, A. F.
2012-01-01
Recent discovery by STEREO A/B of energetic neutral hydrogen is spurring an interest and need for reliable estimates of electron capture cross sections at few MeVs per nucleon as well as for multi-electron ions. Required accuracy in such estimates necessitates detailed and involved quantum-mechanical calculations or expensive numerical simulations. For ENA modeling and similar purposes, a semi-classical approach offers a middle-ground approach. Kuang's semiclassical formalism to calculate electron-capture cross sections for single and multi-electron ions is an elegant and efficient method, but has so far been applied to limited and specific laboratory measurements and at somewhat lower energies. Our goals are to test and extend Kuang s method to all ion-atom and ion-ion collisions relevant to ENA modeling, including multi-electron ions and for K-shell to K-shell transitions.
LHCb cross-section measurements with heavy flavour jets
Michielin, Emanuele
2017-01-01
Cross-section measurements of jets originating from the hadronization of beauty ($b$) and charm ($c$) quarks at LHCb give the unique opportunity to probe Parton Distribution Functions (PDFs) at low and large momentum fraction and to test the Standard Model in the forward region. In this poster the production of $t\\bar{t}$ pairs in the forward region, the measurement of the $W+b\\bar{b}$ and $W+c\\bar{c}$ cross-section and the measurement of the $Z\\rightarrow b\\bar{b}$ cross-section are presented.
Density-dependent photoabsorption cross sections of atomic Xe
Institute of Scientific and Technical Information of China (English)
Ma Xiao-Guang
2009-01-01
The evolution of the photoabsorption cross sections of atomic xenon with number densities varying from ideal gas to condensed matter has been studied by an alternative view in the present work. The alternative expressions of the photoabsorption cross sections presented by Sun et al recently were used with the local field models that has proven to be generalized easily to multiatomic systems including molecules and condensed phase systems. The present results show that the variation of the photoabsorption cross sections of atomic xenon in the giant resonance region from the isolated to the condensed conditions is very small, which agrees well with the variation law of the solid and gas experiments.
Ionization cross section of partially ionized hydrogen plasma
Energy Technology Data Exchange (ETDEWEB)
Baimbetov, F B; Kudyshev, Z A [Department of Physics, al - Farabi Kazakh National University, Almaty (Kazakhstan)], E-mail: Bfb77@kazsu.kz, E-mail: Z.Kudyshev@mail.ru
2008-05-01
In present work the electron impact ionization cross section is considered. The electron impact ionization cross section is calculated, based on pseudopotential model of interaction between plasma particles which accounts correlation effects. It is calculated with help of two methods: classical and quantum - mechanical (Born approximation). The ionization cross section is compared with corresponding results of other authors and experimental data. It has been shown that it is very important to take into account an influence of the surrounding during consideration of ionization processes.
Top quark production cross-section measurements
Massa, Lorenzo; The ATLAS collaboration
2017-01-01
Measurements of the inclusive and differential cross-sections for top-quark pair and single top production cross sections in proton-proton collisions with the ATLAS detector at the Large Hadron Collider are presented at centre-of-mass energies of 8 TeV and 13 TeV. The inclusive measurements reach high precision and are compared to the best available theoretical calculations. These measurements, including results using boosted tops, probe our understanding of top-pair production in the TeV regime. The results are compared to Monte Carlo generators implementing LO and NLO matrix elements matched with parton showers and NLO QCD calculations. For the t-channel single top measurement, the single top-quark and anti-top-quark total production cross-sections, their ratio, as well as differential cross sections are also presented. A measurement of the production crosssection of a single top quark in association with a W boson, the second largest single-top production mode, is also presented. Finally, measurements of t...
Cotton fibre cross-section properties
From a structural perspective the cotton fibre is a singularly discrete, elongated plant cell with no junctions or inter-cellular boundaries. Its form in nature is essentially unadulterated from the field to the spinning mill where its cross-section properties, as for any textile fibre, are central ...
Power corrections in eikonal cross sections
2000-01-01
We discuss power corrections associated with the infrared behavior of the perturbative running coupling in the eikonal approximation to Drell-Yan and other annihilation cross sections in hadron-hadron scattering. General properties of the eikonal approximation imply that only even powers of the energy scale are necessary.
Sarma, Manabendra; Adhikari, S; Mishra, Manoj K
2007-01-28
Vibrational excitation (nu(f), where psi(nu(i))(R,t) approximately =e(-iH(A(2))-(R)t/h phi(nu(i))(R) with time evolution under the influence of the resonance anionic Hamiltonian H(A(2) (-))(A(2) (-)=N(2)(-)/H(2) (-)) implemented using Lanczos and fast Fourier transforms. The target (A(2)) vibrational eigenfunctions phi(nu(i))(R) and phi(nu(f))(R) are calculated using Fourier grid Hamiltonian method applied to potential energy (PE) curves of the neutral target. Application of this simple systematization to calculate vibrational structure in e-N(2) and e-H(2) scattering cross-sections provides mechanistic insights into features underlying presence/absence of structure in e-N(2) and e-H(2) scattering cross-sections. The results obtained with approximate PE curves are in reasonable agreement with experimental/calculated cross-section profiles, and cross correlation functions provide a simple demarcation between the boomerang and impulse models.
Nucleon-nucleon collision profile and cross section fluctuations
Rybczynski, Maciej
2013-01-01
The nucleon-nucleon collision profile, being the basic entity of the wounded nucleon model, is usually adopted in the form of hard sphere or the Gaussian shape. We suggest that the cross section fluctuations given by the gamma distribution leads to the profile function which smoothly ranges between the both limiting forms. Examples demonstrating sensitivity of profile function on cross section fluctuations are discussed.
Regional cross section program for Illinois basin
Energy Technology Data Exchange (ETDEWEB)
Treworgy, J.D.; Whitaker, S.T. (Illinois State Geological Survey, Champaign (USA))
1989-08-01
For the first time, the Illinois State Geological Survey will publish a network of regional cross sections portraying the structural and stratigraphic framework of the entire Illinois basin. The network of 16 structural cross sections radiating outward from the Union Oil 1 Cisne Community well (Sec. 3, T1N, 7E, Wayne County, Illinois) will consist of wireline logs showing formation boundaries and gross lithofacies of the entire stratigraphic column for over 140 wells. Indiana and Kentucky portions of the network will be prepared in conjunction with their respective state geological surveys. Wireline logs are being digitized and stored to allow reproduction of log curves at different scales and in various combinations. Initial cross sections will be published at a vertical scale of 1 in. = 400 ft and a horizontal scale of 1 in. = 8 mi (1:500,000). To assure the most accurate structural and lithologic portrayals possible, numerous wireline logs are being examined in addition to the 140 illustrated on the sections. Available seismic data, sample and core descriptions, and existing structure, isopach, and facies maps are also being used. Text describing the sections will be included on each sheet. Topics will cover a brief history of deposition and structural evolution, distribution of source rocks, reservoir rocks and seals, and significant fields and plays.
Studies of 54,56Fe Neutron Scattering Cross Sections
Directory of Open Access Journals (Sweden)
Hicks S. F.
2015-01-01
Full Text Available Elastic and inelastic neutron scattering differential cross sections and γ-ray production cross sections have been measured on 54,56Fe at several incident energies in the fast neutron region between 1.5 and 4.7 MeV. All measurements were completed at the University of Kentucky Accelerator Laboratory (UKAL using a 7-MV Model CN Van de Graaff accelerator, along with the neutron production and neutron and γ-ray detection systems located there. The facilities at UKAL allow the investigation of both elastic and inelastic scattering with nearly mono-energetic incident neutrons. Time-of-flight techniques were used to detect the scattered neutrons for the differential cross section measurements. The measured cross sections are important for fission reactor applications and also for testing global model calculations such as those found at ENDF, since describing both the elastic and inelastic scattering is important for determining the direct and compound components of the scattering mechanism. The γ-ray production cross sections are used to determine cross sections to unresolved levels in the neutron scattering experiments. Results from our measurements and comparisons to model calculations are presented.
Directory of Open Access Journals (Sweden)
Elise Vaumourin
Full Text Available BACKGROUND: In natural populations, individuals are infected more often by several pathogens than by just one. In such a context, pathogens can interact. This interaction could modify the probability of infection by subsequent pathogens. Identifying when pathogen associations correspond to biological interactions is a challenge in cross-sectional studies where the sequence of infection cannot be demonstrated. METHODOLOGY/PRINCIPAL FINDINGS: Here we modelled the probability of an individual being infected by one and then another pathogen, using a probabilistic model and maximum likelihood statistics. Our model was developed to apply to cross-sectional data, vector-borne and persistent pathogens, and to take into account confounding factors. Our modelling approach was more powerful than the commonly used Chi-square test of independence. Our model was applied to detect potential interaction between Borrelia afzelii and Bartonella spp. that infected a bank vole population at 11% and 57% respectively. No interaction was identified. CONCLUSIONS/SIGNIFICANCE: The modelling approach we proposed is powerful and can identify the direction of potential interaction. Such an approach can be adapted to other types of pathogens, such as non-persistents. The model can be used to identify when co-occurrence patterns correspond to pathogen interactions, which will contribute to understanding how organism communities are assembled and structured. In the long term, the model's capacity to better identify pathogen interactions will improve understanding of infectious risk.
Dogan, Eyup; Seker, Fahri
2016-07-01
This empirical study analyzes the impacts of real income, energy consumption, financial development and trade openness on CO2 emissions for the OECD countries in the Environmental Kuznets Curve (EKC) model by using panel econometric approaches that consider issues of heterogeneity and cross-sectional dependence. Results from the Pesaran CD test, the Pesaran-Yamagata's homogeneity test, the CADF and the CIPS unit root tests, the LM bootstrap cointegration test, the DSUR estimator, and the Emirmahmutoglu-Kose Granger causality test indicate that (i) the panel time-series data are heterogeneous and cross-sectionally dependent; (ii) CO2 emissions, real income, the quadratic income, energy consumption, financial development and openness are integrated of order one; (iii) the analyzed data are cointegrated; (iv) the EKC hypothesis is validated for the OECD countries; (v) increases in openness and financial development mitigate the level of emissions whereas energy consumption contributes to carbon emissions; (vi) a variety of Granger causal relationship is detected among the analyzed variables; and (vii) empirical results and policy recommendations are accurate and efficient since panel econometric models used in this study account for heterogeneity and cross-sectional dependence in their estimation procedures.
Lizzit, D.; Badami, O.; Specogna, R.; Esseni, D.
2017-06-01
We present a new model for surface roughness (SR) scattering in n-type multi-gate FETs (MuGFETs) and gate-all-around nanowire FETs with fairly arbitrary cross-sections, its implementation in a complete device simulator, and the validation against experimental electron mobility data. The model describes the SR scattering matrix elements as non-linear transformations of interface fluctuations, which strongly influences the root mean square value of the roughness required to reproduce experimental mobility data. Mobility simulations are performed via the deterministic solution of the Boltzmann transport equation for a 1D-electron gas and including the most relevant scattering mechanisms for electronic transport, such as acoustic, polar, and non-polar optical phonon scattering, Coulomb scattering, and SR scattering. Simulation results show the importance of accounting for arbitrary cross-sections and biasing conditions when compared to experimental data. We also discuss how mobility is affected by the shape of the cross-section as well as by its area in gate-all-around and tri-gate MuGFETs.
Lukyanov, K V; Lukyanov, V K; Penionzhkevich, Yu E; Sobolev, Y G; Zemlyanaya, E V; Penionzhkevich, Yu.E.; Sobolev, Yu.G.
2007-01-01
The existing and some preliminary experimental data on the total cross sections of the $^{4,6}$He, $^{6,7}$Li +$^{28}$Si reactions at energies E=5-50 A MeV are demonstrated. The data on $^{6}$Li,$^{6}$He+$^{28}$Si are analyzed in the framework of the microscopic optical potential with real and imaginary parts obtained with a help of the double-folding procedure and by using the current models of densities of the projectile nuclei. Besides, the microscopic double-folding Coulomb potential is calculated and its effect on cross sections is compared with that when one applies the traditional Coulomb potential of the uniform charge distribution. The semi-microscopic potentials are constructed from both the renormalized microscopic potentials and their derivatives to take into account collective motion effect and to improve an agreement with experimental data.
Lombardi, Andrea; Faginas-Lago, Noelia; Pacifici, Leonardo; Costantini, Alessandro
2013-11-14
We present extended applications of an established theoretical and computational machinery suitable for the study of the dynamics of CO2+CO2 collisions, focusing on vibrational energy exchange, considered over a wide range of energies and rotational temperatures. Calculations are based on quasi-classical trajectories on a potential energy function (a critical component of dynamics simulations), tailored to accurately describe the intermolecular interactions, modeled by the recently proposed bond-bond semiempirical formulation that allows the colliding molecules to be stretchable, rather than frozen at their equilibrium geometry. In a previous work, the same potential energy surface has been used to show that modifications in the geometry (and in physical properties such as polarizability and charge distribution) of the colliding partners affect the intermolecular interaction and determine the features of the energy exchange, to a large extent driven by long-range forces. As initial partitioning of the energy among the molecular degrees of freedom, we consider the excitation of the vibrational bending mode, assuming an initial rotational distribution and a rotational temperature. The role of the vibrational angular momentum is also carefully assessed. Results are obtained by portable implementations of this approach in a Grid-computing framework and on high performance platforms. Cross sections are basic ingredients to obtain rate constants of use in advanced state-to-state kinetic models, under equilibrium or nonequilibrium conditions, and this approach is suitable for gas dynamics applications to plasmas and modeling of hypersonic flows.
Differential Cross Sections for Proton-Proton Elastic Scattering
Norman, Ryan B.; Dick, Frank; Norbury, John W.; Blattnig, Steve R.
2009-01-01
Proton-proton elastic scattering is investigated within the framework of the one pion exchange model in an attempt to model nucleon-nucleon interactions spanning the large range of energies important to cosmic ray shielding. A quantum field theoretic calculation is used to compute both differential and total cross sections. A scalar theory is then presented and compared to the one pion exchange model. The theoretical cross sections are compared to proton-proton scattering data to determine the validity of the models.
Radar Cross-section Measurement Techniques
Directory of Open Access Journals (Sweden)
V.G. Borkar
2010-03-01
Full Text Available Radar cross-section (RCS is an important study parameter for defence applications specially dealing with airborne weapon system. The RCS parameter guides the detection range for a target and is therefore studied to understand the effectiveness of a weapon system. It is not only important to understand the RCS characteristics of a target but also to look into the diagnostic mode of study where factors contributing to a particular RCS values are studied. This further opens up subject like RCS suppression and stealth. The paper discusses the RCS principle, control, and need of measurements. Classification of RCS in terms of popular usage is explained with detailed theory of RF imaging and inverse synthetic aperture radar (ISAR. The various types of RCS measurement ranges are explained with brief discussion on outdoor RCS measurement range. The RCS calibration plays a critical role in referencing the measurement to absolute values and has been described.The RCS facility at Reseach Centre Imarat, Hyderabad, is explained with some details of different activities that are carried out including RAM evaluation, scale model testing, and diagnostic imaging.Defence Science Journal, 2010, 60(2, pp.204-212, DOI:http://dx.doi.org/10.14429/dsj.60.341
Inclusive and pion production neutrino-nucleus cross sections
Martini, M
2014-01-01
We analyze the experimental data on the inclusive double differential cross section by neutrinos charged current, measured by T2K, with the same model which was successful for the MiniBooNE quasielastic cross sections. As in our previous analysis the multinucleon component is needed in order to reproduce the data. For the total cross section our evaluation is smaller than the SciBooNE data above 1 GeV. This indicates the opening of a new channel not included in our evaluation, presumably the two pion emission channel. We also check that our description holds for the exclusive single pion production channel by confronting our evaluation with the MiniBooNE double differential cross section for a single charged pion and the Q^2 distribution. Both are compatible with data.
A new technique for dosimetry reaction cross-section evaluation
Energy Technology Data Exchange (ETDEWEB)
Badikov, S.A. [JSC Energy and Industry Analytica, 127287, Moscow (Russian Federation)
2011-07-01
Document available in abstract form only, full text of document follows: An objective of this paper is a unification of the procedure for dosimetry reaction cross-section evaluation. A set of requirements for the unified evaluation procedure is presented. A new code (ORTHO) was developed in order to meet these requirements. A statistical model, an algorithm, and the basic formulae employed in the code are described. The code was used for Ti48(n,p) reaction cross-section evaluation. The results of the evaluation are compared to International Reactor Dosimetry File (IRDF)-2002 data. The evaluated cross-sections and their correlations from this work are in good agreement with the IRDF-2002 evaluated data, whereas the uncertainties of the evaluated cross-sections are inconsistent. (authors)
Calculation of the intermediate energy activation cross section
Energy Technology Data Exchange (ETDEWEB)
Furihata, Shiori; Yoshizawa, Nobuaki [Mitsubishi Research Inst., Inc., Tokyo (Japan)
1997-03-01
We discussed the activation cross section in order to predict accurately the activation of soil around an accelerator with high energy and strong intensity beam. For the assessment of the accuracy of activation cross sections estimated by a numerical model, we compared the calculated cross section with various experimental data, for Si(p,x){sup 22}Na, Al(p,x){sup 22}Na, Fe(p,x){sup 22}Na, Si(p,x){sup 7}Be, O(p,x){sup 3}H, Al(p,x){sup 3}H and Si(p,x){sup 3}H reactions. We used three computational codes, i.e., quantum molecular dynamics (QMD) plus statistical decay model (SDM), HETC-3STEP and the semiempirical method developed by Silberberg et.al. It is observed that the codes are accurate above 1GeV, except for {sup 7}Be production. We also discussed the difference between the activation cross sections of proton- and neutron-induced reaction. For the incident energy at 40MeV, it is found that {sup 3}H production cross sections of neutron-induced reaction are ten times as large as those of proton-induced reaction. It is also observed that the choice of the activation cross sections seriously affects to the estimate of saturated radioactivity, if the maximum energy of neutron flux is below 100MeV. (author)
Fagundes, D A; Pancheri, G; Srivastava, Y N; Shekhovtsova, O
2015-01-01
We show that the onset and rise of QCD mini-jets provide the dynamical mechanism behind the appearance of a soft edge in pp collisions around ISR energies and thus such a soft edge is built in our mini-jet model with soft gluon re-summation. Here the model is optimized for LHC at $\\sqrt{s} = 7, 8 TeV$ and predictions are made for higher LHC and cosmic ray energies. Further, we provide a phenomenological picture to discuss the breakup of the total cross-section into its elastic, uncorrelated and correlated inelastic pieces in the framework of a one-channel eikonal function.
Barghouty, A. F.
2012-01-01
Accurate estimates of electron-capture cross sections at energies relevant to energetic neutral atom (ENA) modeling (approx few MeV per nucleon) and for multi-electron ions must rely on first-principles approaches and/or detailed quantum-mechanical simulation of the collision process. Kuang's semi-classical approach offers a middle-ground, elegant and efficient way to arrive at these estimates. We shall present a sample application and current progress in applying and extending Kuang's formalism to ENA modeling.
A genetic algorithm to reduce stream channel cross section data
Berenbrock, C.
2006-01-01
A genetic algorithm (GA) was used to reduce cross section data for a hypothetical example consisting of 41 data points and for 10 cross sections on the Kootenai River. The number of data points for the Kootenai River cross sections ranged from about 500 to more than 2,500. The GA was applied to reduce the number of data points to a manageable dataset because most models and other software require fewer than 100 data points for management, manipulation, and analysis. Results indicated that the program successfully reduced the data. Fitness values from the genetic algorithm were lower (better) than those in a previous study that used standard procedures of reducing the cross section data. On average, fitnesses were 29 percent lower, and several were about 50 percent lower. Results also showed that cross sections produced by the genetic algorithm were representative of the original section and that near-optimal results could be obtained in a single run, even for large problems. Other data also can be reduced in a method similar to that for cross section data.
Energy Technology Data Exchange (ETDEWEB)
Sanami, Toshiya; Baba, Mamoru; Saito, Keiichiro; Ibara, Yasutaka; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering
1997-03-01
We are developing a method of (n,{alpha}) cross section measurement using gaseous samples in a gridded ionization chamber (GIC). This method enables cross section measurements in large solid angle without the distortion by the energy loss in a sample, but requires a method to estimate the detection efficiency. We solve this problem by using GIC signals and a tight neutron collimation. The validity of this method was confirmed through the {sup 12}C(n,{alpha}{sub 0}){sup 9}Be measurement. We applied this method to the {sup 16}O(n,{alpha}){sup 13}C cross section around 14.1 MeV. (author)
Electron impact double ionization cross sections of light elements
Energy Technology Data Exchange (ETDEWEB)
Talukder, M.R. [Rajshahi Univ., Dept. of Applied Physics and Electronic Engineering (Bangladesh); Haque, A.K.F.; Uddin, M.A. [Rajshahi Univ., Dept. of Physics (Bangladesh)
2009-06-15
A simple user-friendly semiempirical model is proposed to calculate electron impact double ionization cross sections of He, Li, Li{sup +}, B{sup +}, C{sup +}, C{sup 3+}, O, O{sup 2+}, O{sup 3+}, Ne, Ne{sup +}, Ne{sup 2+}, Na, Mg, Al{sup 3+}, S, and Ar{sup q+} (q equals 0 - 7) targets for the incident electron energies from threshold to 10{sup 6} eV. The contributions in the total double ionization cross sections from the direct double ionization and inner-shell ionization processes are taken into account on the basis of experimental data considered. The results of the present analysis are compared with the available experimental data and theoretical calculations. The model is found successful for the description of experimental cross sections. Since, this model may be a prudent selection to meet the demand level in plasma modeling due to its simple inherent structure. (authors)
Light stops emerging in WW cross section measurements?
Energy Technology Data Exchange (ETDEWEB)
Rolbiecki, Krzysztof [IFT-UAM/CSIC, Madrid (Spain). Inst. de Fisica Teorica; Sakurai, Kazuki [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2013-03-15
Recent ATLAS and CMS measurements show a slight excess in the WW cross section measurement. While still consistent with the Standard Model within 1-2{sigma}, the excess could be also a first hint of physics beyond the Standard Model. We argue that this effect could be attributed to the production of scalar top quarks within supersymmetric models. The stops of m{sub t{sub 1}}{proportional_to}200 GeV has the right cross section and under some assumptions can significantly contribute to the final state of two leptons and missing energy. We scan this region of parameter space to find particle masses preferred by the WW cross section measurements. Taking one sample benchmark point we show that it can be consistent with low energy observables and Higgs sector measurements and propose a method to distinguish supersymmetric signal from the Standard Model contribution.
Rotational averaging of multiphoton absorption cross sections
Energy Technology Data Exchange (ETDEWEB)
Friese, Daniel H., E-mail: daniel.h.friese@uit.no; Beerepoot, Maarten T. P.; Ruud, Kenneth [Centre for Theoretical and Computational Chemistry, University of Tromsø — The Arctic University of Norway, N-9037 Tromsø (Norway)
2014-11-28
Rotational averaging of tensors is a crucial step in the calculation of molecular properties in isotropic media. We present a scheme for the rotational averaging of multiphoton absorption cross sections. We extend existing literature on rotational averaging to even-rank tensors of arbitrary order and derive equations that require only the number of photons as input. In particular, we derive the first explicit expressions for the rotational average of five-, six-, and seven-photon absorption cross sections. This work is one of the required steps in making the calculation of these higher-order absorption properties possible. The results can be applied to any even-rank tensor provided linearly polarized light is used.
Rotational averaging of multiphoton absorption cross sections
Friese, Daniel H.; Beerepoot, Maarten T. P.; Ruud, Kenneth
2014-11-01
Rotational averaging of tensors is a crucial step in the calculation of molecular properties in isotropic media. We present a scheme for the rotational averaging of multiphoton absorption cross sections. We extend existing literature on rotational averaging to even-rank tensors of arbitrary order and derive equations that require only the number of photons as input. In particular, we derive the first explicit expressions for the rotational average of five-, six-, and seven-photon absorption cross sections. This work is one of the required steps in making the calculation of these higher-order absorption properties possible. The results can be applied to any even-rank tensor provided linearly polarized light is used.
Measurements of neutron spallation cross section. 2
Energy Technology Data Exchange (ETDEWEB)
Kim, E.; Nakamura, T. [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center; Imamura, M.; Nakao, N.; Shibata, S.; Uwamino, Y.; Nakanishi, N.; Tanaka, Su.
1997-03-01
Neutron spallation cross section of {sup 59}Co(n,xn){sup 60-x}Co, {sup nat}Cu(n,sp){sup 56}Mn, {sup nat}Cu(n,sp){sup 58}Co, {sup nat}Cu(n,xn){sup 60}Cu, {sup nat}Cu(n,xn){sup 61}Cu and {sup nat}Cu(n,sp){sup 65}Ni was measured in the quasi-monoenergetic p-Li neutron fields in the energy range above 40 MeV which have been established at three AVF cyclotron facilities of (1) INS of Univ. of Tokyo, (2) TIARA of JAERI and (3) RIKEN. Our experimental data were compared with the ENDF/B-VI high energy file data by Fukahori and the calculated cross section data by Odano. (author)
Lugaro, Maria; Karakas, Amanda I; Milazzo, Paolo M; Kaeppeler, Franz; Davis, Andrew M; Savina, Michael R
2013-01-01
We present model predictions for the Zr isotopic ratios produced by slow neutron captures in C-rich asymptotic giant branch (AGB) stars of masses 1.25 to 4 Msun and metallicities Z=0.01 to 0.03, and compare them to data from single meteoritic stardust silicon carbide (SiC) and high-density graphite grains that condensed in the outflows of these stars. We compare predictions produced using the Zr neutron-capture cross section from Bao et al. (2000) and from n_TOF experiments at CERN, and present a new evaluation for the neutron-capture cross section of the unstable isotope 95Zr, the branching point leading to the production of 96Zr. The new cross sections generally presents an improved match with the observational data, except for the 92Zr/94Zr ratios, which are on average still substantially higher than predicted. The 96Zr/94Zr ratios can be explained using our range of initial stellar masses, with the most 96Zr-depleted grains originating from AGB stars of masses 1.8 - 3 Msun, and the others from either lowe...
Inclusive jet cross section at D0
Energy Technology Data Exchange (ETDEWEB)
Bhattacharjee, M. [Delhi Univ. (India). Dept. of Physics and Astrophysics
1996-09-01
Preliminary measurement of the central ({vert_bar}{eta}{vert_bar} {<=} 0.5) inclusive jet cross sections for jet cone sizes of 1.0, 0.7, and 0.5 at D{null} based on the 1992-1993 (13.7 {ital pb}{sup -1}) and 1994-1995 (90 {ital pb}{sup -1}) data samples are presented. Comparisons to Next-to-Leading Order (NLO) Quantum Chromodynamics (QCD) calculations are made.
Inclusive jet cross section measurement at CDF
Energy Technology Data Exchange (ETDEWEB)
Pagliarone, C. [Universita di Torino and INFN, Trieste (Italy)
1996-08-01
The CDF Collaboration has measured the inclusive jet cross section using 1992-93 collider data at 1.8 TeV. The CDF measurement is in very good agreement with NLO QCD predictions for transverse energies (E{sub T}) below 200 GeV. However, it is systematically higher than NLO QCD predictions for E{sub T} above 200 GeV.
Measurements of Fission Cross Sections of Actinides
Wiescher, M; Cox, J; Dahlfors, M
2002-01-01
A measurement of the neutron induced fission cross sections of $^{237}$Np, $^{241},{243}$Am and of $^{245}$Cm is proposed for the n_TOF neutron beam. Two sets of fission detectors will be used: one based on PPAC counters and another based on a fast ionization chamber (FIC). A total of 5x10$^{18}$ protons are requested for the entire fission measurement campaign.
Cross section of the CMS solenoid
Tejinder S. Virdee, CERN
2005-01-01
The pictures show a cross section of the CMS solenoid. One can see four layers of the superconducting coil, each of which contains the superconductor (central part, copper coloured - niobium-titanium strands in a copper coating, made into a "Rutherford cable"), surrounded by an ultra-pure aluminium as a magnetic stabilizer, then an aluminium alloy as a mechanical stabilizer. Besides the four layers there is an aluminium mechanical piece that includes pipes that transport the liquid helium.
Fully double-logarithm-resummed cross sections
Energy Technology Data Exchange (ETDEWEB)
Albino, S.; Bolzoni, P.; Kniehl, B.A. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Kotikov, A. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Joint Inst. of Nuclear Research, Moscow (Russian Federation). Bogoliubov Lab. of Theoretical Physics
2011-04-15
We calculate the complete double logarithmic contribution to cross sections for semi-inclusive hadron production in the modified minimal-subtraction (MS) scheme by applying dimensional regularization to the double logarithm approximation. The full double logarithmic contribution to the coefficient functions for inclusive hadron production in electron-positron annihilation is obtained in this scheme for the first time. Our result agrees with all fixed order results in the literature, which extend to next-next-to-leading order. (orig.)
Dijet cross sections in photoproduction at HERA
Energy Technology Data Exchange (ETDEWEB)
Makarenko, Inna [DESY, Hamburg (Germany)
2012-07-01
At high collision energies accessible at ep collider HERA hard hadronic jets can be produced. At leading order, at low virtualities of the exchanged photon, two processes contribute to the jet production. In the direct photon process an almost real photon interacts as a point-like particle with a parton of the proton. In contrast in resolved processes the photon fluctuates to an hadronic state. The measurements of the jet production give an important information about the structure of the photon and the proton. Dijet cross sections have been measured in the reaction ep{yields} e+jet+jet+X with the ZEUS detector using an integrated luminosity of 189 pb{sup -1}. Differential cross sections are presented as functions of average jet transverse energy and presudorapidity for dijet events with E{sub T}{sup jet1} > 21 GeV, E{sub T}{sup jet2} > 17 GeV, -1 < {eta}{sup jet1(2)} < 3 for {gamma}p centre-of-mass energies in range 142 < W{sub {gamma}p} < 293 GeV and photon virtuality Q{sup 2} < 1 GeV{sup 2}. In addition, the dijet cross section was measured as a function of the fraction of the incoming photon momentum taken by the dijet system. The dijet cross sections were also measured as functions of the dijet invariant mass, M{sub jj} and scattering angle in the dijet centre-of-mass system for E{sub T}{sup jet1(2)} > 17 GeV, -1 < {eta}{sup jet1(2)} < 3 and M{sub jj} > 60 GeV. Next-to-leading order calculations give a good description of the measurements. These measurements can be used to further constraint the gluon component of the proton parton density function at medium to high x.
Fusion cross sections measurements with MUSIC
Carnelli, P. F. F.; Fernández Niello, J. O.; Almaraz-Calderon, S.; Rehm, K. E.; Albers, M.; Digiovine, B.; Esbensen, H.; Henderson, D.; Jiang, C. L.; Nusair, O.; Palchan-Hazan, T.; Pardo, R. C.; Ugalde, C.; Paul, M.; Alcorta, M.; Bertone, P. F.; Lai, J.; Marley, S. T.
2014-09-01
The interaction between exotic nuclei plays an important role for understanding the reaction mechanism of the fusion processes as well as for the energy production in stars. With the advent of radioactive beams new frontiers for fusion reaction studies have become accessible. We have performed the first measurements of the total fusion cross sections in the systems 10 , 14 , 15C + 12C using a newly developed active target-detector system (MUSIC). Comparison of the obtained cross sections with theoretical predictions show a good agreement in the energy region accessible with existing radioactive beams. This type of comparison allows us to calibrate the calculations for cases that cannot be studied in the laboratory with the current experimental capabilities. The high efficiency of this active detector system will allow future measurements with even more neutron-rich isotopes. The interaction between exotic nuclei plays an important role for understanding the reaction mechanism of the fusion processes as well as for the energy production in stars. With the advent of radioactive beams new frontiers for fusion reaction studies have become accessible. We have performed the first measurements of the total fusion cross sections in the systems 10 , 14 , 15C + 12C using a newly developed active target-detector system (MUSIC). Comparison of the obtained cross sections with theoretical predictions show a good agreement in the energy region accessible with existing radioactive beams. This type of comparison allows us to calibrate the calculations for cases that cannot be studied in the laboratory with the current experimental capabilities. The high efficiency of this active detector system will allow future measurements with even more neutron-rich isotopes. This work is supported by the U.S. DOE Office of Nuclear Physics under Contract No. DE-AC02-06CH11357 and the Universidad Nacional de San Martin, Argentina, Grant SJ10/39.
MCNPX Simulations for Neutron Cross Section Measurements
Tesinsky, Milan
2010-01-01
This thesis presents MCNPX simulations of the SCANDAL set-up used at the Theodor Svedberg Laboratory for neutron scattering cross-section measurements. The thesis describes processes and data important for the upcoming off-line data analysis. In the experiment, neutrons scattered off the target are converted to protons which are stopped in scintillator crystals. The results of presented simulations include a description of the proton spectra in dependence of the neutron-to-proton conversion a...
Inelastic cross section measurements at LHC
Bindi, M; The ATLAS collaboration
2012-01-01
The dependence of the rate of proton–proton interactions on the centre-of-mass collision energy, √s, is of fundamental importance for both hadron collider physics and particle astrophysics. The dependence cannot yet be calculated from first principles; therefore, experimental measurements are needed. Here we present the first measurements of the inelastic proton–proton interaction cross-section at a centre-of-mass energy, √s, of 7 TeV using the ATLAS and CMS detectors at the Large Hadron Collider. For ATLAS the events are selected by requiring hits on scintillation counters mounted in the forward region of the detector. An inelastic cross-section of 60.3 ± 2.1 mb is measured for ξ > 5×10−6, where ξ is calculated from the invariant mass, MX, of hadrons selected using the largest rapidity gap in the event. For diffractive events, this corresponds to requiring at least one of the dissociation masses to be larger than 15.7 GeV. For CMS a new method to measure the inelastic pp cross section ha...
Energy Technology Data Exchange (ETDEWEB)
Merle, Elsa [Laboratoire d' Annecy-le-vieux de physique des particules, Grenoble-1 Univ., 74 Annecy (France)
1999-04-22
The present work is based on the selection of e{sup -}e{sup +} {yields} f f-bar events taken with the ALEPH detector from 1995 to 1998, for an integrated luminosity of 500 pb{sup -}. We first present the selection of dimuon, di-tau and di-electron events that we have been developed for this study. The hadronic selection used in ALEPH is also detailed in a devoted part. In each case, the estimation of systematic uncertainties is described. They are of the same order of magnitude as the statistical errors, ranging between 0.6% (di-electron) and 3.5% (dimuon). From these selections we derive the di-fermionic cross-sections as well as the asymmetries computed for the di-lepton channels. Measurements are found to be in reasonable agreement with the Standard Model expectations. Cross-sections and asymmetries are sensitive to the presence of possible new physics. In this document we use the context of the 4-fermion contact interactions to set limits on the energy scale of new physics. Such limits are found to range between 7 and 15 GeV depending on the modelling used. We also put lower limits on the mass of leptoquarks, 590 GeV/c{sup 2} for vector leptoquarks and 71 GeV/c{sup 2} for scalar leptoquarks. Eventually we also present the limits derived in the context of R-parity violated supersymmetry, putting constraint on the s-neutrino mass. Our study excludes such particles below a few hundred GeV/c{sup 2} mass for high values of their Yukawa coupling assumptions.
McQuarrie, N.; Ehlers, T. A.; Rak, A. J.
2015-12-01
A critical component in assessing the viability of proposed plate tectonic or geodynamic processes in regions of convergence is the expected or predicted age and rate of deformation in the overriding plate. Commonly, age of deformation is inferred through geochronology of foreland basin and wedge-top sedimentary rocks and bedrock thermochronometer cooling signals. In Bolivia the original pulse of deformation of the fold-thrust belt is argue to be as young as 38-25 Ma based on the age of synorogenic strata or as old as 65-45 Ma due to proposed foreland basin rocks deposited in the Bolivian Altiplano. The large discrepancies in proposed age, rate and magnitude of deformation through the Bolivian Andes limit our ability to relate age and rate of shortening to internal geodynamic or external plate tectonic processes. We evaluate permissible ranges in age of initiation and rate of deformation through a forward kinematic model of the northern Bolivian fold-thrust belt. Each step of deformation accounts for isostatic loading from thrust faults and subsequent erosional of structural highs. The kinematic model predicts an evolution of flexural basins into which synorogenic sediments are deposited allowing us to fully integrate age of exhumation and deposition to age and magnitude of deformation. By assigning an age to each deformation step, we create a range of velocity vectors that are input into the thermokinematic model Pecube, which predicts thermochronometer cooling histories based on kinematics, topography, thermal parameters and shortening rates. We match the pattern of predicted ages with the across strike pattern of measured zircon fission track, apatite fission track and apatite (U-Th)/ He cooling ages. The sensitivity of modeled thermochronologic data to the age at which deformation initiates indicate that northern Bolivian EC started deforming at 50 Ma and may have begun as early as 55 Ma. The acceptable velocity envelope for the modeled section permits either a
Electron cross-sections and transport in liquids and biomolecules
White, Ronald; Casey, M.; Cocks, D.; Konvalov, D.; Brunger, M. J.; Garcia, G.; Petrovic, Z.; McEachran, R.; Buckman, S. J.; de Urquijo, J.
2016-09-01
Modelling of electron induced processes in plasma medicine and radiation damage is reliant on accurate self-consistent sets of cross-sections for electrons in tissue. These cross-sections (and associated transport theory) must accurately account not only the electron-biomolecule interactions but also for the soft-condensed nature of tissue. In this presentation, we report on recent swarm experiments for electrons in gaseous water and tetrahydrofuran using the pulsed-Townsend experiment, and the associated development of self-consistent cross-section sets that arise from them. We also report on the necessary modifications to gas-phase cross-sections required to accurately treat electron transport in liquids. These modifications involve the treatment of coherent scattering and screening of the electron interaction potential as well as the development of a new transport theory to accommodate these cross-sections. The accuracy of the ab-initio cross-sections is highlighted through comparison of theory and experiment for electrons in liquid argon and xenon.
Coulomb and nuclear effects in breakup and reaction cross sections
Descouvemont, P.; Canto, L. F.; Hussein, M. S.
2017-01-01
We use a three-body continuum discretized coupled channel (CDCC) model to investigate Coulomb and nuclear effects in breakup and reaction cross sections. The breakup of the projectile is simulated by a finite number of square integrable wave functions. First we show that the scattering matrices can be split in a nuclear term and in a Coulomb term. This decomposition is based on the Lippmann-Schwinger equation and requires the scattering wave functions. We present two different methods to separate both effects. Then, we apply this separation to breakup and reaction cross sections of 7Li+208Pb . For breakup, we investigate various aspects, such as the role of the α +t continuum, the angular-momentum distribution, and the balance between Coulomb and nuclear effects. We show that there is a large ambiguity in defining the Coulomb and nuclear breakup cross sections, since both techniques, although providing the same total breakup cross sections, strongly differ for the individual components. We suggest a third method which could be efficiently used to address convergence problems at large angular momentum. For reaction cross sections, interference effects are smaller, and the nuclear contribution is dominant above the Coulomb barrier. We also draw attention to different definitions of the reaction cross section which exist in the literature and which may induce small, but significant, differences in the numerical values.
Wiegand, Ryan E; Rose, Charles E; Karon, John M
2016-12-01
A potential difficulty in the analysis of biomarker data occurs when data are subject to a detection limit. This detection limit is often defined as the point at which the true values cannot be measured reliably. Multiple, regression-type models designed to analyze such data exist. Studies have compared the bias among such models, but few have compared their statistical power. This simulation study provides a comparison of approaches for analyzing two-group, cross-sectional data with a Gaussian-distributed outcome by exploring statistical power and effect size confidence interval coverage of four models able to be implemented in standard software. We found using a Tobit model fit by maximum likelihood provides the best power and coverage. An example using human immunodeficiency virus type 1 ribonucleic acid data is used to illustrate the inferential differences in these models.
Reaction cross sections of the deformed halo nucleus 31Ne
Urata, Y; Sagawa, H
2012-01-01
Using the Glauber theory, we calculate reaction cross sections for the deformed halo nucleus $^{31}$Ne. To this end, we assume that the $^{31}$Ne nucleus takes the $^{30}$Ne + $n$ structure. In order to take into account the rotational excitation of the core nucleus $^{30}$Ne, we employ the particle-rotor model (PRM). We compare the results to those in the adiabatic limit of PRM, that is, the Nilsson model, and show that the Nilsson model works reasonably well for the reaction cross sections of $^{31}$Ne. We also investigate the dependence of the reaction cross sections on the ground state properties of $^{31}$Ne, such as the deformation parameter and the p-wave component in the ground state wave function.
Energy Technology Data Exchange (ETDEWEB)
Becker, C.H.
1978-12-01
Differential cross sections I (THETA) at several collision energies measured in crossed molecular beam experiments are reported for several combinations of halogen atoms (/sup 2/P) scattered off rare gas-rare gas atoms (/sup 1/S/sub 0/), namely, F + Ne, F + Ar, F + Kr, F + Xe, C1 + Xe. The scattering is described by an elastic model appropriate to Hund's case c coupling. With the use of this model, the X 1/2, I 3/2, and II 1/2 interaction potential energy curves are derived by fitting calculated differential cross sections, based on analytic representations of the potentials, to the data. The F - Xe X 1/2 potential shows a significant bonding qualitatively different than for the other F-rare gases. The I 3/2 and II 1/2 potentials closely resemble the van der Waals interactions of the one electron richer ground state rare gas-rare gas systems. Coupled-channel scattering calculations are carried out for F + Ar, F + Xe, and C1 + Xe using the realistic potential curves derived earlier. The results justify the use of the elastic model, and give additional information on intramultiplet and intermultiplet transitions. The transitions are found to be governed by the crossing of the two ..cap omega.. = 1/2 potentials in the complex plane. The measured I (theta) and I (THETA) derived from the coupled-channel computations show small oscillations or perturbations (Stueckelberg oscillations) though quantitative agreement is not obtained.The nature of the anomalous F - Xe X 1/2 potential is discussed as is the approximation of a constant spin orbit coupling over the experimentally accessible range of internuclear distances for these open shell molecules. 55 references.
Energy Technology Data Exchange (ETDEWEB)
Heltsley, B.K.
1976-04-01
In hadron-proton collisions at high energies, the impact profile function measures the range and strength of the strong interaction. It determines the effective size and shape of the hadrons involved, for purposes of both elastic scattering and particle production, but depends solely upon the behavior in t of the elastic differential cross-section. Such an analysis of the reactions ..pi.. +- p, K +- p, and p +- p at incident momenta from 50 to 175 GeV/c is presented using the elastic scattering data recently taken. Two derivations of the profile function are given: the classic optical model and the partial wave treatment. The first stresses the ''grey disc'' interpretations of hadrons; both allow the decomposition of the profile into the elastic and inelastic overlap functions, which represent the probabilities of each of the two processes. A more rigorous procedure yielding essentially the same result involves the imposition of unitarity on the relativistic S-matrix and then requiring angular momentum conservation. Cross section measurements extend to t = -0.8 (GeV/c)/sup 2/; this calculation assumes pure exponential behavior thereafter, and accounts for the possibility of a sharp decrease in its slope at larger t. The real part of the scattering amplitude is neglected. The results display good qualitative agreement with the shadow-diffraction scattering model, and with previous analyses. They indicate distinct differences between meson-baryon and baryon-baryon interactions, and imply that dependence of the cross section on energy derives primarily from a net change in peripheral processes. A test of the quark model and the Lipkin sum rules shows substantial deviation from theoretical expectations.
Ulmer, W
2010-01-01
A recapitulatory analysis of total nuclear cross sections of various nuclei is presented, which yields detailed knowledge on the different physical processes such as potential/resonance scatter and nuclear reactions. The physical base for potential/resonance scatter and the threshold energy resulting from Coulomb repulsion of nuclei are collective/oscillator models. The part pertaining to the nuclear reactions can only be determined by the microscopic theory (Schr\\"odinger equation and strong interactions). The physical impact is the fluence decrease of proton beams in different media and the scatter behavior of secondary particles.
Electron transport in silicon nanowires having different cross-sections
Directory of Open Access Journals (Sweden)
Muscato Orazio
2016-06-01
Full Text Available Transport phenomena in silicon nanowires with different cross-section are investigated using an Extended Hydrodynamic model, coupled to the Schrödinger-Poisson system. The model has been formulated by closing the moment system derived from the Boltzmann equation on the basis of the maximum entropy principle of Extended Thermodynamics, obtaining explicit closure relations for the high-order fluxes and the production terms. Scattering of electrons with acoustic and non polar optical phonons have been taken into account. The bulk mobility is evaluated for square and equilateral triangle cross-sections of the wire.
New cross sections for H on H2 collisional transitions
Zou, Qianxia
The cross section for H on H2 collisions is important for astrophysics as well as our understanding of the simple chemical systems. This is the simplest atom-molecule cross section. With a new H3 potential surface by Mielke et al., we have modified the ABC code by Skouteris, Castillo and Manolopoulos to calculate new cross sections. These cross sections are compared to previous cross section calculations.
Averaging cross section data so we can fit it
Energy Technology Data Exchange (ETDEWEB)
Brown, D. [Brookhaven National Lab. (BNL), Upton, NY (United States). NNDC
2014-10-23
The ^{56}Fe cross section we are interested in have a lot of fluctuations. We would like to fit the average of the cross section with cross sections calculated within EMPIRE. EMPIRE is a Hauser-Feshbach theory based nuclear reaction code, requires cross sections to be smoothed using a Lorentzian profile. The plan is to fit EMPIRE to these cross sections in the fast region (say above 500 keV).
Klevansky, S P
2016-01-01
Recently Dai and Pennington have performed a comprehensive analysis of essentially all pion and kaon pair production data from two-photon collisions below 1.5 GeV, including all high statistics results from Belle, as well as the older data from Mark II at SLAC, CELLO at DESY, and Crystal Ball at SLAC. Imposing the basic constraints required by analyticity, unitarity, and crossing symmetry and making use of Low's low energy theorem for QED, they are able to extract the final-state strong-interaction scattering amplitudes for the intermediate pi pi->pi pi and pi pi-> K\\bar K reactions in a model-independent fashion. In addition, they provide good fits to the respective gamma gamma-> pi pi cross-sections that are known in the low-energy sector in the restricted angular range, | cos theta|pi pi cross-sections integrated over the full angular range. In this work, we use a version of chiral perturbation theory developed by Oller and Oset to evaluate the final-state strong-interaction amplitudes directly theoretical...
Cross-section fluctuations in chaotic scattering systems
Ericson, Torleif E. O.; Dietz, Barbara; Richter, Achim
2016-10-01
Exact analytical expressions for the cross-section correlation functions of chaotic scattering systems have hitherto been derived only under special conditions. The objective of the present article is to provide expressions that are applicable beyond these restrictions. The derivation is based on a statistical model of Breit-Wigner type for chaotic scattering amplitudes which has been shown to describe the exact analytical results for the scattering (S )-matrix correlation functions accurately. Our results are given in the energy and in the time representations and apply in the whole range from isolated to overlapping resonances. The S -matrix contributions to the cross-section correlations are obtained in terms of explicit irreducible and reducible correlation functions. Consequently, the model can be used for a detailed exploration of the key features of the cross-section correlations and the underlying physical mechanisms. In the region of isolated resonances, the cross-section correlations contain a dominant contribution from the self-correlation term. For narrow states the self-correlations originate predominantly from widely spaced states with exceptionally large partial width. In the asymptotic region of well-overlapping resonances, the cross-section autocorrelation functions are given in terms of the S -matrix autocorrelation functions. For inelastic correlations, in particular, the Ericson fluctuations rapidly dominate in that region. Agreement with known analytical and experimental results is excellent.
Fission cross section measurements for minor actinides
Energy Technology Data Exchange (ETDEWEB)
Fursov, B. [IPPE, Obninsk (Russian Federation)
1997-03-01
The main task of this work is the measurement of fast neutron induced fission cross section for minor actinides of {sup 238}Pu, {sup 242m}Am, {sup 243,244,245,246,247,248}Cm. The task of the work is to increase the accuracy of data in MeV energy region. Basic experimental method, fissile samples, fission detectors and electronics, track detectors, alpha counting, neutron generation, fission rate measurement, corrections to the data and error analysis are presented in this paper. (author)
Neutron capture cross section of $^{93}$Zr
We propose to measure the neutron capture cross section of the radioactive isotope $^{93}$Zr. This project aims at the substantial improvement of existing results for applications in nuclear astrophysics and emerging nuclear technologies. In particular, the superior quality of the data that can be obtained at n_TOF will allow on one side a better characterization of s-process nucleosynthesis and on the other side a more accurate material balance in systems for transmutation of nuclear waste, given that this radioactive isotope is widely present in fission products.
Automatic Computation of Cross Sections in HEP
Yuasa, F; Ishikawa, T; Jimbo, M; Kaneko, T; Kato, K; Kawabata, S; Kon, T; Kurihara, Y; Kuroda, M; Nakazawa, N; Shimizu, Y; Tanaka, H
2000-01-01
For the study of reactions in High Energy Physics (HEP) automatic computation systems have been developed and are widely used nowadays. GRACE is one of such systems and it has achieved much success in analyzing experimental data. Since we deal with the cross section whose value can be given by calculating hundreds of Feynman diagrams, we manage the large scale calculation, so that effective symbolic manipulation, the treat of singularity in the numerical integration are required. The talk will describe the software design of GRACE system and computational techniques in the GRACE.
Critical behavior of cross sections at LHC
Dremin, I. M.
2016-07-01
Recent experimental data on elastic scattering of high energy protons show that the critical regime has been reached at LHC energies. The approach to criticality is demonstrated by increase of the ratio of elastic to total cross sections from ISR to LHC energies. At LHC it reaches the value which can result in principal change of the character of proton interactions. The treatment of new physics of hollowed toroid-like hadrons requires usage of another branch of the unitarity condition. Its further fate is speculated and interpreted with the help of the unitarity condition in combination with present experimental data. The gedanken experiments to distinguish between different possibilities are proposed.
LEP vacuum chamber, cross-section
CERN PhotoLab
1983-01-01
Cross-section of the final prototype for the LEP vacuum chamber. The elliptic main-opening is for the beam. The small channel to the left is for the cooling water, to carry away the heat deposited by the synchrotron radiation. The square channel to the right houses the Non-Evaporable Getter (NEG) pump. The chamber is made from extruded aluminium. Its outside is clad with lead, to stop the synchrotron radiation emitted by the beam. For good adherence between Pb and Al, the Al chamber was coated with a thin layer of Ni. Ni being slightly magnetic, some resulting problems had to be overcome. See also 8301153.
Critical behavior of cross sections at LHC
Dremin, I M
2016-01-01
Recent experimental data on elastic scattering of high energy protons show that the critical regime has been reached at LHC energies. The approach to criticality is demonstrated by increase of the ratio of elastic to total cross sections from ISR to LHC energies. At LHC it reaches the value which can result in principal change of the character of proton interactions. The treatment of new physics of hollowed toroid-like hadrons requires usage of another branch of the unitarity condition. Its further fate is speculated and interpreted with the help of the unitarity condition in combination with present experimental data. The gedanken experiments to distinguish between different possibilities are proposed.
Multicollinearity in cross-sectional regressions
Lauridsen, Jørgen; Mur, Jesùs
2006-10-01
The paper examines robustness of results from cross-sectional regression paying attention to the impact of multicollinearity. It is well known that the reliability of estimators (least-squares or maximum-likelihood) gets worse as the linear relationships between the regressors become more acute. We resolve the discussion in a spatial context, looking closely into the behaviour shown, under several unfavourable conditions, by the most outstanding misspecification tests when collinear variables are added to the regression. A Monte Carlo simulation is performed. The conclusions point to the fact that these statistics react in different ways to the problems posed.
Fission cross section measurements for minor actinides
Energy Technology Data Exchange (ETDEWEB)
Fursov, B. [IPPE, Obninsk (Russian Federation)
1997-03-01
The main task of this work is the measurement of fast neutron induced fission cross section for minor actinides of {sup 238}Pu, {sup 242m}Am, {sup 243,244,245,246,247,248}Cm. The task of the work is to increase the accuracy of data in MeV energy region. Basic experimental method, fissile samples, fission detectors and electronics, track detectors, alpha counting, neutron generation, fission rate measurement, corrections to the data and error analysis are presented in this paper. (author)
Top cross section measurements at ATLAS
Okumura, Y; The ATLAS collaboration
2011-01-01
We present a measurement of the top-quark pair-production in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector at the Large Hadron Collider using the full 2010 data sample. The cross sections are measured in the lepton+jets and dilepton channels. This is a 15 minute talk (+ 6min discussion) to be given at "DIS2011" Workshop , Newport News, VA USA. The conference starts on April 11, 2011. The talk is scheduled for April 13, 2011.
Poškus, A.
2016-09-01
This paper evaluates the accuracy of the single-event (SE) and condensed-history (CH) models of electron transport in MCNP6.1 when simulating characteristic Kα, total K (=Kα + Kβ) and Lα X-ray emission from thick targets bombarded by electrons with energies from 5 keV to 30 keV. It is shown that the MCNP6.1 implementation of the CH model for the K-shell impact ionization leads to underestimation of the K yield by 40% or more for the elements with atomic numbers Z 25. The Lα yields are underestimated by more than an order of magnitude in CH mode, because MCNP6.1 neglects X-ray emission caused by electron-impact ionization of L, M and higher shells in CH mode (the Lα yields calculated in CH mode reflect only X-ray fluorescence, which is mainly caused by photoelectric absorption of bremsstrahlung photons). The X-ray yields calculated by MCNP6.1 in SE mode (using ENDF/B-VII.1 library data) are more accurate: the differences of the calculated and experimental K yields are within the experimental uncertainties for the elements C, Al and Si, and the calculated Kα yields are typically underestimated by (20-30)% for the elements with Z > 25, whereas the Lα yields are underestimated by (60-70)% for the elements with Z > 49. It is also shown that agreement of the experimental X-ray yields with those calculated in SE mode is additionally improved by replacing the ENDF/B inner-shell electron-impact ionization cross sections with the set of cross sections obtained from the distorted-wave Born approximation (DWBA), which are also used in the PENELOPE code system. The latter replacement causes a decrease of the average relative difference of the experimental X-ray yields and the simulation results obtained in SE mode to approximately 10%, which is similar to accuracy achieved with PENELOPE. This confirms that the DWBA inner-shell impact ionization cross sections are significantly more accurate than the corresponding ENDF/B cross sections when energy of incident electrons
Weissman, David E.; Davidson, Kenneth L.; Brown, Robert A.; Friehe, Carl A.; Li, Fuk
1994-01-01
The Frontal Air-Sea Interaction Experiment (FASINEX) provided a unique data set with coincident airborne scatterometer measurements of the ocean surface radar cross section (RCS)(at Ku band) and near-surface wind and wind stress. These data have been analyzed to study new model functions which relate wind speed and surface friction velocity (square root of the kinematic wind stress) to the radar cross section and to better understand the processes in the boundary layer that have a strong influence on the radar backscatter. Studies of data from FASINEX indicate that the RCS has a different relation to the friction velocity than to the wind speed. The difference between the RCS models using these two variables depends on the polarization and the incidence angle. The radar data have been acquired from the Jet Propulsion Laboratory airborne scatterometer. These data span 10 different flight days. Stress measurements were inferred from shipboard instruments and from aircraft flying at low altitudes, closely following the scatterometer. Wide ranges of radar incidence angles and environmental conditions needed to fully develop algorithms are available from this experiment.
Improved Actinide Neutron Capture Cross Sections Using Accelerator Mass Spectrometry
Bauder, W.; Pardo, R. C.; Kondev, F. G.; Kondrashev, S.; Nair, C.; Nusair, O.; Palchan, T.; Scott, R.; Seweryniak, D.; Vondrasek, R.; Collon, P.; Paul, M.; Youinou, G.; Salvatores, M.; Palmotti, G.; Berg, J.; Maddock, T.; Imel, G.
2014-09-01
The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are developing a technique to inject solid material into the ECR with laser ablation. With laser ablation, we can better control material injection and potentially increase efficiency in the ECR, thus creating less contamination in the source and reducing cross talk. I will present work on the laser ablation system and preliminary results from our AMS measurements. The MANTRA (Measurement of Actinide Neutron TRAnsmutations) project will improve energy-integrated neutron capture cross section data across the actinide region. These data are incorporated into nuclear reactor models and are an important piece in understanding Generation IV reactor designs. We will infer the capture cross sections by measuring isotopic ratios from actinide samples, irradiated in the Advanced Test Reactor at INL, with Accelerator Mass Spectrometry (AMS) at ATLAS (ANL). The superior sensitivity of AMS allows us to extract multiple cross sections from a single sample. In order to analyze the large number of samples needed for MANTRA and to meet the goal of extracting multiple cross sections per sample, we have made a number of modifications to the AMS setup at ATLAS. In particular, we are
Top quark cross section measurements with ATLAS
Skubic, P; The ATLAS collaboration
2014-01-01
Measurements of the inclusive top quark pair production cross sections in proton-proton collisions with the ATLAS detector at the Large Hadron Collider are presented. The measurements are performed requiring one or two electrons or muons in the final state. Various experimental techniques are compared. The most precise result requires events with an electron and a muon of opposite sign and uses the full data-set at a centre-of-mass energy of 8 TeV. The data are in good agreement with a recent NNLO+NNLL QCD calculation. Measurements of the differential top quark pair production cross sections in proton-proton collisions with the ATLAS detector at the Large Hadron Collider are also presented. The measurements are performed requiring one electron or muon in the final state and are carried out differentially in the reconstructed top transverse momentum, and the invariant mass, rapidity and transverse momentum of the top pair system. These measurements probe our understanding of top pair production in the TeV regi...
Energy Technology Data Exchange (ETDEWEB)
Lugaro, Maria [Monash Centre for Astrophysics (MoCA), Monash University, Clayton, VIC 3800 (Australia); Tagliente, Giuseppe [Istituto Nazionale di Fisica Nucleare (INFN), Bari (Italy); Karakas, Amanda I. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Milazzo, Paolo M. [Istituto Nazionale di Fisica Nucleare (INFN), Trieste (Italy); Käppeler, Franz [Karlsruhe Institute of Technology, Campus North, D-76021 Karlsruhe (Germany); Davis, Andrew M. [The Department of the Geophysical Sciences, The University of Chicago, Chicago, IL 60637 (United States); Savina, Michael R., E-mail: maria.lugaro@monash.edu, E-mail: giuseppe.tagliente@ba.infn.it, E-mail: amanda.karakas@anu.edu.au, E-mail: paolo.milazzo@ts.infn.it, E-mail: franz.kaeppeler@kit.edu, E-mail: a-davis@uchicago.edu, E-mail: msavina@anl.gov [Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States)
2014-01-01
We present model predictions for the Zr isotopic ratios produced by slow neutron captures in C-rich asymptotic giant branch (AGB) stars of masses 1.25-4 M {sub ☉} and metallicities Z = 0.01-0.03, and compare them to data from single meteoritic stardust silicon carbide (SiC) and high-density graphite grains that condensed in the outflows of these stars. We compare predictions produced using the Zr neutron-capture cross sections from Bao et al. and from n{sub T}OF experiments at CERN, and present a new evaluation for the neutron-capture cross section of the unstable isotope {sup 95}Zr, the branching point leading to the production of {sup 96}Zr. The new cross sections generally present an improved match with the observational data, except for the {sup 92}Zr/{sup 94}Zr ratios, which are on average still substantially higher than predicted. The {sup 96}Zr/{sup 94}Zr ratios can be explained using our range of initial stellar masses, with the most {sup 96}Zr-depleted grains originating from AGB stars of masses 1.8-3 M {sub ☉} and the others from either lower or higher masses. The {sup 90,} {sup 91}Zr/{sup 94}Zr variations measured in the grains are well reproduced by the range of stellar metallicities considered here, which is the same needed to cover the Si composition of the grains produced by the chemical evolution of the Galaxy. The {sup 92}Zr/{sup 94}Zr versus {sup 29}Si/{sup 28}Si positive correlation observed in the available data suggests that stellar metallicity rather than rotation plays the major role in covering the {sup 90,} {sup 91,} {sup 92}Zr/{sup 94}Zr spread.
GENIE implementation of IFIC Valencia model for QE-like 2p2h neutrino-nucleus cross section
Schwehr, J; Gran, R
2016-01-01
The model by Nieves, Ruiz-Simo, and Vicente-Vacas and their group (IFIC, Valencia, Spain) for 2p2h reactions that produce QE-like (no pion) final states has been implemented in GENIE. Since the model currently does not predict the kinematics of the outgoing hadrons, a simple two-nucleon system is grafted onto the model's prediction of isospin, energy transfer, and momentum transfer. These two nucleons are then given to the GENIE FSI models. This whitepaper is a guide to the kind of information available from this model and some limitations. There are several figures that illustrate the output of the model, and detailed discussion of the physics context for this model. Finally, any other authors' model (or variations of this one) that can be expressed as hadronic tensors for total and pn initial state will be easy to incorporate into this framework.
Heat Transfer in a Concrete Composite Cross-Section
Directory of Open Access Journals (Sweden)
Klabník Maroš
2016-12-01
Full Text Available The work is concerned with the spread of heat in 2D coupled cross section with respect to the material characteristics and boundary conditions of calculation. Heat transfer was simulated in the program ANSYS in time interval up to 180 minutes. Nine various models were created to investigate the rate of influence of the changes in thermal material characteristics such as the specific heat capacity coefficient and thermal conductivity, upon the course and difference of temperature in the concrete cross-section. The comparison of results obtained using non-linear and constant values of the variables in simulation was made, too.
Timoshenko beam element with anisotropic cross-sectional properties
DEFF Research Database (Denmark)
Stäblein, Alexander; Hansen, Morten Hartvig
2016-01-01
Beam models are used for the aeroelastic time and frequency domain analysis of wind turbines due to their computational efficiency. Many current aeroelastic tools for the analysis of wind turbines rely on Timoshenko beam elements with classical crosssectional properties (EA, EI, etc.). Those cross......-sectional properties do not reflect the various couplings arising from the anisotropic behaviour of the blade material. A twonoded, three-dimensional Timoshenko beam element was therefore extended to allow for anisotropic cross-sectional properties. For an uncoupled beam, the resulting shape functions are identical...
Electromagnetic Dissociation Cross Sections using Weisskopf-Ewing Theory
Adamczyk, Anne M.; Norbury, John W.
2011-01-01
It is important that accurate estimates of crew exposure to radiation are obtained for future long-term space missions. Presently, several space radiation transport codes exist to predict the radiation environment, all of which take as input particle interaction cross sections that describe the nuclear interactions between the particles and the shielding material. The space radiation transport code HZETRN uses the nuclear fragmentation model NUCFRG2 to calculate Electromagnetic Dissociation (EMD) cross sections. Currently, NUCFRG2 employs energy independent branching ratios to calculate these cross sections. Using Weisskopf-Ewing (WE) theory to calculate branching ratios, however, is more advantageous than the method currently employed in NUCFRG2. The WE theory can calculate not only neutron and proton emission, as in the energy independent branching ratio formalism used in NUCFRG2, but also deuteron, triton, helion, and alpha particle emission. These particles can contribute significantly to total exposure estimates. In this work, photonuclear cross sections are calculated using WE theory and the energy independent branching ratios used in NUCFRG2 and then compared to experimental data. It is found that the WE theory gives comparable, but mainly better agreement with data than the energy independent branching ratio. Furthermore, EMD cross sections for single neutron, proton, and alpha particle removal are calculated using WE theory and an energy independent branching ratio used in NUCFRG2 and compared to experimental data.
Theoretical Formalism To Estimate the Positron Scattering Cross Section.
Singh, Suvam; Dutta, Sangita; Naghma, Rahla; Antony, Bobby
2016-07-21
A theoretical formalism is introduced in this article to calculate the total cross sections for positron scattering. This method incorporates positron-target interaction in the spherical complex optical potential formalism. The study of positron collision has been quite subtle until now. However, recently, it has emerged as an interesting area due to its role in atomic and molecular structure physics, astrophysics, and medicine. With the present method, the total cross sections for simple atoms C, N, and O and their diatomic molecules C2, N2, and O2 are obtained and compared with existing data. The total cross section obtained in the present work gives a more consistent shape and magnitude than existing theories. The characteristic dip below 10 eV is identified due to the positronium formation. The deviation of the present cross section with measurements at energies below 10 eV is attributed to the neglect of forward angle-discrimination effects in experiments, the inefficiency of additivity rule for molecules, empirical treatment of positronium formation, and the neglect of annihilation reactions. In spite of these deficiencies, the present results show consistent behavior and reasonable agreement with previous data, wherever available. Besides, this is the first computational model to report positron scattering cross sections over the energy range from 1 to 5000 eV.
Total cross sections for (e sup - -He) ionization
Energy Technology Data Exchange (ETDEWEB)
Mukherjee, K.K. (Novodaya Vidyalaya, Manipur, (IN)); Keka Basu Choudhury, (Jadavpur Univ. Calcutta, (IN). Dept. of Physics); Mazumdar, P.S.; Brajamani, S. (Manipur Univ. (IN). Dept. of Physics)
1991-01-01
Total cross sections for electron impact ionization have been calculated in the energy range 40-150 eV in a distorted wave model which employs distorted waves for the incident, scattered and ejected electrons. The present results are compared with experimental results and other theoretical predictions.
NNLO corrections to the Higgs production cross section
Energy Technology Data Exchange (ETDEWEB)
Ravindran, V. [Harish-Chandra Research Institute, Chhatnag Road, Jhusii, Allahabad, 211019 (India); Smith, J. [C.N. Yang Institute for Theoretical Physics, State University of New York at Stony Brook, New York 11794-3840 (United States); Neerven, W.L. van [Instituut-Lorentz, Universiteit Leiden, PO Box 9506, 2300 RA Leiden (Netherlands)
2004-10-01
We discuss the next-to-next-to-leading order (NNLO) corrections to the total cross section for (pseudo-) scalar Higgs boson production. The computation is carried out in the e.ective Lagrangian approach which emerges from the standard model by taking the limit mt->{approx} where mt denotes the mass of the top quark.
Electron Impact Ionization Cross Section of Nitrogen Atoms
Institute of Scientific and Technical Information of China (English)
YU Rong-Mei; ZHOU Ya-Jun; WANG Yang; JIAO Li-Guang
2006-01-01
The direct ionization cross sections for electron scattering by nitrogen are calculated by applying an equivalentlocal optical model from 15eV to 1100eV. The present results are compared with the experimental data and other theoretical calculation results.
Cross sections and kinematics of proton induced fragmentation of carbon
Energy Technology Data Exchange (ETDEWEB)
Streibel, T.; Roecher, H.; Huentrup, G.; Heinrich, W. [Siegen Univ. (Germany). Dept. of Physics
1997-09-01
Charge changing fragmentation cross sections for C at a proton energy of about 70 MeV were measured. The discrepancies between measurement and model predictions indicate the necessity of further investigations. We have also measured distributions of fragment emission angles which can be described using a model with a momentum transfer to the fragmenting nucleus. The developed model leads to predictions for momentum distributions of proton induced target fragments of C at small energies. (orig.)
Proton-air and proton-proton cross sections
Directory of Open Access Journals (Sweden)
Ulrich Ralf
2013-06-01
Full Text Available Different attempts to measure hadronic cross sections with cosmic ray data are reviewed. The major results are compared to each other and the differences in the corresponding analyses are discussed. Besides some important differences, it is crucial to see that all analyses are based on the same fundamental relation of longitudinal air shower development to the observed fluctuation of experimental observables. Furthermore, the relation of the measured proton-air to the more fundamental proton-proton cross section is discussed. The current global picture combines hadronic proton-proton cross section data from accelerator and cosmic ray measurements and indicates a good consistency with predictions of models up to the highest energies.
Total Cross Section in $\\gamma\\gamma$ Collisions at LEP
Acciarri, M; Adriani, O; Aguilar-Benítez, M; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Ambrosi, G; Anderhub, H; Andreev, V P; Angelescu, T; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Bajo, A; Baksay, L; Balandras, A; Baldew, S V; Todorova-Nová, S; Banerjee, Sw; Barczyk, A; Barillère, R; Bartalini, P; Basile, M; Batalova, N; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Bellucci, L; Berbeco, R; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Bhattacharya, S; Biasini, M; Biland, A; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böhm, A; Boldizsar, L; Borgia, B; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brochu, F; Buffini, A; Buijs, A; Burger, J D; Burger, W J; Cai, X D; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Castellini, G; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada, M; Cesaroni, F; Chamizo-Llatas, M; Chang, Y H; Chaturvedi, U K; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chiefari, G; Cifarelli, Luisa; Cindolo, F; Civinini, C; Clare, I; Clare, R; Coignet, G; Colino, N; Costantini, S; Cotorobai, F; de la Cruz, B; Csilling, Akos; Cucciarelli, S; Dai, T S; van Dalen, J A; D'Alessandro, R; De Asmundis, R; Déglon, P L; Degré, A; Deiters, K; Della Volpe, D; Delmeire, E; Denes, P; De Notaristefani, F; De Salvo, A; Diemoz, M; Dierckxsens, M; Van Dierendonck, D N; Dionisi, C; Dittmar, Michael; Dominguez, A; Doria, A; Dova, M T; Duchesneau, D; Dufournaud, D; Duinker, P; El-Mamouni, H; Engler, A; Eppling, F J; Erné, F C; Ewers, A; Extermann, Pierre; Fabre, M; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, Marta; Ferguson, T; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisk, I; Forconi, G; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gau, S S; Gentile, S; Gheordanescu, N; Giagu, S; Gong, Z F; Grenier, G; Grimm, O; Grünewald, M W; Guida, M; van Gulik, R; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hasan, A; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hidas, P; Hirschfelder, J; Hofer, H; Holzner, G; Hoorani, H; Hou, S R; Hu, Y; Iashvili, I; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Khan, R A; Käfer, D; Kaur, M; Kienzle-Focacci, M N; Kim, D; Kim, J K; Kirkby, Jasper; Kiss, D; Kittel, E W; Klimentov, A; König, A C; Kopal, M; Kopp, A; Koutsenko, V F; Kräber, M H; Krämer, R W; Krenz, W; Krüger, A; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Lee, H J; Le Goff, J M; Leiste, R; Levchenko, P M; Li Chuan; Likhoded, S A; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lü, Y S; Lübelsmeyer, K; Luci, C; Luckey, D; Lugnier, L; Luminari, L; Lustermann, W; Ma Wen Gan; Maity, M; Malgeri, L; Malinin, A; Maña, C; Mangeol, D J J; Mans, J; Marian, G; Martin, J P; Marzano, F; Mazumdar, K; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Von der Mey, M; Mihul, A; Milcent, H; Mirabelli, G; Mnich, J; Mohanty, G B; Moulik, T; Muanza, G S; Muijs, A J M; Musicar, B; Musy, M; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Niessen, T; Nisati, A; Nowak, H; Ofierzynski, R A; Organtini, G; Oulianov, A; Palomares, C; Pandoulas, D; Paoletti, S; Paolucci, P; Paramatti, R; Park, H K; Park, I H; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Pedace, M; Pensotti, S; Perret-Gallix, D; Petersen, B; Piccolo, D; Pierella, F; Pieri, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Postema, H; Pothier, J; Prokofiev, D O; Prokofev, D; Quartieri, J; Rahal-Callot, G; Rahaman, M A; Raics, P; Raja, N; Ramelli, R; Rancoita, P G; Ranieri, R; Raspereza, A V; Raven, G; Razis, P A; Ren, D; Rescigno, M; Reucroft, S; Riemann, S; Riles, K; Rodin, J; Roe, B P; Romero, L; Rosca, A; Rosier-Lees, S; Roth, S; Rosenbleck, C; Roux, B; Rubio, Juan Antonio; Ruggiero, G; Rykaczewski, H; Saremi, S; Sarkar, S; Salicio, J; Sánchez, E; Sanders, M P; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Schopper, Herwig Franz; Schotanus, D J; Schwering, G; Sciacca, C; Seganti, A; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shumilov, E; Shvorob, A V; Siedenburg, T; Son, D; Smith, B; Spillantini, P; Steuer, M; Stickland, D P; Stone, A; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Sushkov, S V; Suter, H; Swain, J D; Szillási, Z; Sztaricskai, T; Tang, X W; Tauscher, Ludwig; Taylor, L; Tellili, B; Teyssier, D; Timmermans, C; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Uchida, Y; Ulbricht, J; Valente, E; Vesztergombi, G; Vetlitskii, I; Vicinanza, D; Viertel, Gert M; Villa, S; Vivargent, M; Vlachos, S; Vodopyanov, I; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Vorvolakos, A; Wadhwa, M
2001-01-01
The reaction e+e- -> e+e- gamma* gamma* -> e+e- hadrons for quasi-real photons is studied using data from root(s) = 183 GeV up to 202 GeV. Results on the total cross sections sigma(e+e- -> e+e- hadrons) and sigma(+e- gamma* gamma* -> e+e- hadrons) are given for the two-photon centre-of-mass energies 5 GeV < Wgammagamma < 185 GeV. The total cross section of two real photons is described by a Regge parametrisation. We observe a steeper rise with the two-photon centre-of-mass energy as compared to the hadron-hadron and the photon-proton cross sections. The data are also compared to the expectations of different theoretical models.
Pion photoproduction cross section at large momentum transfer
Energy Technology Data Exchange (ETDEWEB)
Sjoegren, Johan [Univ. of Glasgow, Scotland, United Kingdom
2015-02-27
The Real Compton Scattering experiment was performed in Hall A at the Thomas Jefferson National Accelerator Facility. It was designed to measure, for Compton scattering and π^{0}-photoproduction, the differential cross section over a range of kinematic points and the polarisation transfer to the proton at a single kinematic point. The full range of the experiment in Mandelstam variables t and s was 1.6-6.46 GeV^{2} and 4.82-10.92 GeV^{2} respectively with beam energies of 2-6 GeV. The motivation for the experiment is to test the cross section and polarisation transfer predictions of perturbative QCD versus that of predictions from Generalised Parton Distribution models. This thesis will give an overview of the pertinent theory, experimental setup in Hall A and the extracting of the π^{0}-photoproduction cross section.
U.S. Geological Survey, Department of the Interior — This digital dataset defines the traces of geologic and hydrogeologic cross sections that were used in the construction of a digital three-dimensional (3D)...
U.S. Geological Survey, Department of the Interior — This digital dataset defines the traces of geologic and hydrogeologic cross sections that were used in the construction of a digital three-dimensional (3D)...
Energy Technology Data Exchange (ETDEWEB)
Kaufmann, O.; Martin, T. [Service de Geologie Fondamentale et Appliquee, Mons (Belgium). Faculte Polytechnique de Mons
2008-03-15
In a wide range of applications involving geological modelling, geological data available at low cost usually consist of documents such as cross-sections or geological maps and punctual data like borehole logs or outcrop descriptions. In order to build accurate 3D geological models based on this information, it is necessary to develop a methodology that takes into account the variety of available data. Such models, of the geometry of geological bodies, should also be easy to edit and update to integrate new data. This kind of model should produce a consistent representation of subsurface geology that may be a support for modelling other subsoil characteristics such as hydrogeologic or geothermic properties of the geological bodies. This paper presents a methodology developed to process geological information in this context. The aims of this methodology are comprehensive data description, effective data validation and easier model updates. Thus, special attention has been given to data structures and processing flows. The adopted methodology is implemented on a system architecture formed by a geographic information system, a geomodeler and a database communicating by file transfers. An application of this methodology, to build a 3D geological model of the subsoil over former coalmines used to store natural gas, is then presented. This model integrates the geological information available and is representative of the geoloigical context. It is a support to the environmental follow-up needed after the end of gas-storage operations.
Propagation of sound waves in tubes of noncircular cross section
Richards, W. B.
1986-01-01
Plane-acoustic-wave propagation in small tubes with a cross section in the shape of a flattened oval is described. Theoretical descriptions of a plane wave propagating in a tube with circular cross section and between a pair of infinite parallel plates, including viscous and thermal damping, are expressed in similar form. For a wide range of useful duct sizes, the propagation constant (whose real and imaginary parts are the amplitude attenuation rate and the wave number, respectively) is very nearly the same function of frequency for both cases if the radius of the circular tube is the same as the distance between the parallel plates. This suggests that either a circular-cross-section model or a flat-plate model can be used to calculate wave propagation in flat-oval tubing, or any other shape tubing, if its size is expressed in terms of an equivalent radius, given by g = 2 x (cross-sectional area)/(length of perimeter). Measurements of the frequency response of two sections of flat-oval tubing agree with calculations based on this idea. Flat-plate formulas are derived, the use of transmission-line matrices for calculations of plane waves in compound systems of ducts is described, and examples of computer programs written to carry out the calculations are shown.
Determination of Ultimate Torque for Multiply Connected Cross Section Rod
Directory of Open Access Journals (Sweden)
V. L. Danilov
2015-01-01
Full Text Available The aim of this work is to determine load-carrying capability of the multiply cross-section rod. This calculation is based on the model of the ideal plasticity of the material, so that the desired ultimate torque is a torque at which the entire cross section goes into a plastic state.The article discusses the cylindrical multiply cross-section rod. To satisfy the equilibrium equation and the condition of plasticity simultaneously, two stress function Ф and φ are introduced. By mathematical transformations it has been proved that Ф is constant along the path, and a formula to find its values on the contours has been obtained. The paper also presents the rationale of the line of stress discontinuity and obtained relationships, which allow us to derive the equations break lines for simple interaction of neighboring circuits, such as two lines, straight lines and circles, circles and a different sign of the curvature.After substitution into the boundary condition at the end of the stress function Ф and mathematical transformations a formula is obtained to determine the ultimate torque for the multiply cross-section rod.Using the doubly connected cross-section and three-connected cross-section rods as an example the application of the formula of ultimate torque is studied.For doubly connected cross-section rod, the paper offers a formula of the torque versus the radius of the rod, the aperture radius and the distance between their centers. It also clearly demonstrates the torque dependence both on the ratio of the radii and on the displacement of hole. It is shown that the value of the torque is more influenced by the displacement of hole, rather than by the ratio of the radii.For the three-connected cross-section rod the paper shows the integration feature that consists in selection of a coordinate system. As an example, the ultimate torque is found by two methods: analytical one and 3D modeling. The method of 3D modeling is based on the Nadai
Directory of Open Access Journals (Sweden)
E. Gerasopoulos
2009-07-01
Full Text Available In this study, aerosol optical depth (AOD measurements, from a MFR sun photometer operating in Athens, were compared with columnar dust loading estimations, from the BSC-DREAM model, during identified dust events, in order to extract the typical specific extinction cross-section for dust over the area. The selected urban environment of Athens provided us with the opportunity to investigate the mixing of dust and urban pollution and to estimate the contribution of the latter. The specific extinction cross-section for dust at 500 nm was found to be equal to σ_{500}^{*}=0.64±0.04 m^{2} g, typical for medium to large distances from dust sources, with weak wavelength dependence in the visible and near infrared band (0.4–0.9 μm. The model showed a tendency to underpredict AOD levels for increasing values of the Ångström exponent, indicative of fine particles of anthropogenic origin inside the boundary layer. On average we found an AOD under-prediction of 10–15% for Ångström exponents in the range of 0 to 1 and 30–40% in the range of 1 to 2. Additionally, modelled surface concentrations were evaluated against surface PM_{10} measurements. Model values were lower than measured surface concentrations by 30% which, in conjunction with large scatter, indicated that the effect of the boundary layer anthropogenic contribution to columnar dust loadings is amplified near the ground.
Cohen, Laurent D.; Cohen, Isaac
1990-01-01
The use of energy-minimizing curves, known as "snakes" to extract features of interest in images has been introduced by Kass, Witkin & Terzopoulos. We present a model of deformation which solves some of the problems encountered with the original method such as instability and initial data while reducing the computational complexity. This model makes the curve behave like a balloon which is inflated by an additional force. The initial curve need no longer be close to the solution to converge. ...
ISSUES IN NEUTRON CROSS SECTION COVARIANCES
Energy Technology Data Exchange (ETDEWEB)
Mattoon, C.M.; Oblozinsky,P.
2010-04-30
We review neutron cross section covariances in both the resonance and fast neutron regions with the goal to identify existing issues in evaluation methods and their impact on covariances. We also outline ideas for suitable covariance quality assurance procedures.We show that the topic of covariance data remains controversial, the evaluation methodologies are not fully established and covariances produced by different approaches have unacceptable spread. The main controversy is in very low uncertainties generated by rigorous evaluation methods and much larger uncertainties based on simple estimates from experimental data. Since the evaluators tend to trust the former, while the users tend to trust the latter, this controversy has considerable practical implications. Dedicated effort is needed to arrive at covariance evaluation methods that would resolve this issue and produce results accepted internationally both by evaluators and users.
Surface Reconstruction for Cross Sectional Data
Institute of Scientific and Technical Information of China (English)
徐美和; 唐泽圣
1996-01-01
In this paper,a new solution to the problem of reconstructing the surface of 3D objects over a set of cross-sectional contours is proposed.An algorithm for single branch contours connection,which is based on the closest local polar angle method,is first presented.Then the branching problems(including non-singular branchin and singular branching)are completely solved by decomposing them into several single-branching problems.Finally,these methods are applied to the reconstruction of the external surface of a complexly shaped object such as the cellular region of human brain.The results show that the presented methods are practical and satisfactory.
Absolute photoneutron cross sections of Sm isotopes
Energy Technology Data Exchange (ETDEWEB)
Gheorghe, I.; Glodariu, T. [National Institute for Physics and Nuclear Engineering Horia Hulubei, str. Atomistilor nr. 407 (Romania); Utsunomiya, H. [Department of Physics, Konan University, Okamoto 8-9-1, Higashinada, Kobe 658-8501 (Japan); Filipescu, D. [Extreme Light Infrastructure - Nuclear Physics, str. Atomistilor nr. 407, Bucharest-Magurele, P.O.BOX MG6 and National Institute for Physics and Nuclear Engineering Horia Hulubei, str. Atomistilor nr. 407 (Romania); Nyhus, H.-T.; Renstrom, T. [Department of Physics, University of Oslo, N-0316 Oslo (Norway); Tesileanu, O. [Extreme Light Infrastructure - Nuclear Physics, str. Atomistilor nr. 407, Bucharest-Magurele, P.O.BOX MG6 (Romania); Shima, T.; Takahisa, K. [Research Center for Nuclear Physics, Osaka University, Suita, Osaka 567-0047 (Japan); Miyamoto, S. [Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 3-1-2 Kouto, Kamigori, Hyogo 678-1205 (Japan)
2015-02-24
Photoneutron cross sections for seven samarium isotopes, {sup 144}Sm, {sup 147}Sm, {sup 148}Sm, {sup 149}Sm, {sup 150}Sm, {sup 152}Sm and {sup 154}Sm, have been investigated near neutron emission threshold using quasimonochromatic laser-Compton scattering γ-rays produced at the synchrotron radiation facility NewSUBARU. The results are important for nuclear astrophysics calculations and also for probing γ-ray strength functions in the vicinity of neutron threshold. Here we describe the neutron detection system and we discuss the related data analysis and the necessary method improvements for adapting the current experimental method to the working parameters of the future Gamma Beam System of Extreme Light Infrastructure - Nuclear Physics facility.
Measurement of thermal neutron capture cross section
Huang Xiao Long; LuHanLin; Yu Wei Xiang; Zhao Wen Rong
2001-01-01
The thermal neutron capture cross sections of sup 7 sup 1 Ga(n, gamma) sup 7 sup 2 Ga, sup 9 sup 4 Zr(n, gamma) sup 9 sup 5 Zr and sup 1 sup 9 sup 1 Ir(n, gamma) sup 1 sup 9 sup 2 Ir sup m sup 1 sup + sup g sup , sup m sup 2 reactions were measured by using activation method and compared with other measured data. Meanwhile the half-life of sup 7 sup 2 Ga was also measured. The samples were irradiated with the neutron in the thermal column of heavy water reactor of China Institute of Atomic Energy. The activities of the reaction products were measured by well-calibrated Ge(Li) detector
Lunar Radar Cross Section at Low Frequency
Rodriguez, P.; Kennedy, E. J.; Kossey, P.; McCarrick, M.; Kaiser, M. L.; Bougeret, J.-L.; Tokarev, Y. V.
2002-01-01
Recent bistatic measurements of the lunar radar cross-section have extended the spectrum to long radio wavelength. We have utilized the HF Active Auroral Research Program (HAARP) radar facility near Gakona, Alaska to transmit high power pulses at 8.075 MHz to the Moon; the echo pulses were received onboard the NASA/WIND spacecraft by the WAVES HF receiver. This lunar radar experiment follows our previous use of earth-based HF radar with satellites to conduct space experiments. The spacecraft was approaching the Moon for a scheduled orbit perturbation when our experiment of 13 September 2001 was conducted. During the two-hour experiment, the radial distance of the satellite from the Moon varied from 28 to 24 Rm, where Rm is in lunar radii.
ISSUES IN NEUTRON CROSS SECTION COVARIANCES
Energy Technology Data Exchange (ETDEWEB)
Mattoon, C.M.; Oblozinsky,P.
2010-04-30
We review neutron cross section covariances in both the resonance and fast neutron regions with the goal to identify existing issues in evaluation methods and their impact on covariances. We also outline ideas for suitable covariance quality assurance procedures.We show that the topic of covariance data remains controversial, the evaluation methodologies are not fully established and covariances produced by different approaches have unacceptable spread. The main controversy is in very low uncertainties generated by rigorous evaluation methods and much larger uncertainties based on simple estimates from experimental data. Since the evaluators tend to trust the former, while the users tend to trust the latter, this controversy has considerable practical implications. Dedicated effort is needed to arrive at covariance evaluation methods that would resolve this issue and produce results accepted internationally both by evaluators and users.
Electroweak Boson Cross-Section Measurements
The ATLAS collaboration
2009-01-01
This report summarises the ATLAS prospects for the measurement of W and Z pro- duction cross-section at the LHC. The electron and muon decay channels are considered. Focusing on the early data taking phase, strategies are presented that allow a fast and robust extraction of the signals. An overall uncertainty of about 5% can be achieved with 50 pb−1 in the W channels, where the background uncertainty dominates (the luminosity measurement uncertainty is not discussed here). In the Z channels, the expected preci- sion is 3%, the main contribution coming from the lepton selection efﬁciency uncertainty. Extrapolating to 1 fb−1 , the uncertainties shrink to incompressible values of 1-2%, de- pending on the ﬁnal state. This irreducible uncertainty is essentially driven by strong interaction effects, notably parton distribution uncertainties and non-perturbative effects, affecting the W and Z rapidity and transverse momentum distributions. These effects can be constrained by measuring these distributions. Al...
Radar Cross Section of Moving Objects
Gholizade, H
2013-01-01
I investigate the effects of movement on radar cross section calculations. The results show that relativistic effects (the constant velocity case) can change the RCS of moving targets by changing the incident plane wave field vectors. As in the Doppler effect, the changes in the fields are proportional to $\\frac{v}{c}$. For accelerated objects, using the Newtonian equations of motion yields an effective electric field (or effective current density) on the object due to the finite mass of the conducting electrons. The results indicate that the magnetic moment of an accelerated object is different from that of an un-accelerated object, and this difference can change the RCS of the object. Results for moving sphere and non-uniformly rotating sphere are given and compared with static (\\textbf{v}=0) case.
Plasma-based radar cross section reduction
Singh, Hema; Jha, Rakesh Mohan
2016-01-01
This book presents a comprehensive review of plasma-based stealth, covering the basics, methods, parametric analysis, and challenges towards the realization of the idea. The concealment of aircraft from radar sources, or stealth, is achieved through shaping, radar absorbing coatings, engineered materials, or plasma, etc. Plasma-based stealth is a radar cross section (RCS) reduction technique associated with the reflection and absorption of incident electromagnetic (EM) waves by the plasma layer surrounding the structure. A plasma cloud covering the aircraft may give rise to other signatures such as thermal, acoustic, infrared, or visual. Thus it is a matter of concern that the RCS reduction by plasma enhances its detectability due to other signatures. This needs a careful approach towards the plasma generation and its EM wave interaction. The book starts with the basics of EM wave interactions with plasma, briefly discuss the methods used to analyze the propagation characteristics of plasma, and its generatio...
Experimental Investigation Of Polymeric Compound Cross Section Springs
Directory of Open Access Journals (Sweden)
Mayas Al-Mahasne
2007-01-01
Full Text Available This paper presents an experimental investigation of the characteristic of the compound cross section springs on models made from polymeric materials (organic glass. Two constructive variants of the compound spring sections were specified with the help of criteria of similarity. The criterion of similarity of natural and model springs was determined by the simulation method at particular spring deflection. The problem of simulation was brought to accurate determination of the magnitudes that characterize the physical and mechanical properties of materials for natural and model springs. It was experimentally proved that the use of the proposed new type of springs significantly increases the spring stiffness.
Directory of Open Access Journals (Sweden)
Katz Patricia P
2010-05-01
Full Text Available Abstract Background Diverse environmental exposures, studied separately, have been linked to health outcomes in adult asthma, but integrated multi-factorial effects have not been modeled. We sought to evaluate the contribution of combined social and physical environmental exposures to adult asthma lung function and disease severity. Methods Data on 176 subjects with asthma and/or rhinitis were collected via telephone interviews for sociodemographic factors and asthma severity (scored on a 0-28 point range. Dust, indoor air quality, antigen-specific IgE antibodies, and lung function (percent predicted FEV1 were assessed through home visits. Neighborhood socioeconomic status, proximity to traffic, land use, and ambient air quality data were linked to the individual-level data via residential geocoding. Multiple linear regression separately tested the explanatory power of five groups of environmental factors for the outcomes, percent predicted FEV1 and asthma severity. Final models retained all variables statistically associated (p Results Mean FEV1 was 85.0 ± 18.6%; mean asthma severity score was 6.9 ± 5.6. Of 29 variables screened, 13 were retained in the final model of FEV1 (R2 = 0.30; p 2 = 0.16; p 1 as an independent variable to the severity model further increased its explanatory power (R2 = 0.25. Conclusions Multivariate models covering a range of individual and environmental factors explained nearly a third of FEV1 variability and, taking into account lung function, one quarter of variability in asthma severity. These data support an integrated approach to modeling adult asthma outcomes, including both the physical and the social environment.
Biancamaria, S.; Garambois, P. A.; Calmant, S.; Roux, H.; Paris, A.; Monnier, J.; Santos da Silva, J.
2015-12-01
Hydrodynamic laws predict that irregularities in a river bed geometry produce spatial and temporal variations in the water level, hence in its slope. Conversely, observation of these changes is a goal of the SWOT mission with the determination of the discharge as a final objective. In this study, we analyse the relationship between river bed undulations and water surface for an ungauged reach of the Xingu river, a first order tributary of the Amazon river. It is crosscut more than 10 times by a single ENVISAT track over a hundred of km. We have determined time series of water levelsat each of these crossings, called virtual stations (VS), hence slopes of the flow line. Using the discharge series computed by Paiva et al. (2013) between 1998 and 2009, Paris et al. (submitted) determined at each VS a rating curve relating these simulated discharge with the ENVISAT height series. One parameter of these rating curves is the zero-flow depth Z 0 . We show that it is possible to explain the spatial and temporal variations of the water surface slope in terms of hydrodynamical response of the longitudinal changes of the river bed geometry given by the successive values of Z 0 . Our experiment is based on an effective, single thread representation of a braided river, realistic values for the Manning coefficient and river widths picked up on JERS images. This study confirms that simulated flow lines are consistent with water surface elevations (WSE) and slopes gained by satellite altimetry. Hydrodynamical signatures are more visible where the river bed geometry varies significantly, and for reaches with a strong downstream control. Therefore, this study suggests that the longitudinal variations of the slope might be an interesting criteria for the question of river segmentation into elementary reaches for the SWOT mission which will provide continuous measurements of the water surface elevation, the slope and the reach width.
SU-E-I-43: Photoelectric Cross Section Revisited
Energy Technology Data Exchange (ETDEWEB)
Haga, A; Nakagawa, K [The University of Tokyo Hospital, Tokyo (Japan); Kotoku, J [Teikyo University, Tokyo (Japan); Horikawa, Y [Juntendo University, Tokyo, Tokyo (Japan)
2015-06-15
Purpose: The importance of the precision in photoelectric cross-section value increases for recent developed technology such as dual energy computed tomography, in which some reconstruction algorithms require the energy dependence of the photo-absorption in each material composition of human being. In this study, we revisited the photoelectric cross-section calculation by self-consistent relativistic Hartree-Fock (HF) atomic model and compared with that widely distributed as “XCOM database” in National Institute of Standards and Technology, which was evaluated with localdensity approximation for electron-exchange (Fock)z potential. Methods: The photoelectric cross section can be calculated with the electron wave functions in initial atomic state (bound electron) and final continuum state (photoelectron). These electron states were constructed based on the selfconsistent HF calculation, where the repulsive Coulomb potential from the electron charge distribution (Hartree term) and the electron exchange potential with full electromagnetic interaction (Fock term) were included for the electron-electron interaction. The photoelectric cross sections were evaluated for He (Z=2), Be (Z=4), C (Z=6), O (Z=8), and Ne (Z=10) in energy range of 10keV to 1MeV. The Result was compared with XCOM database. Results: The difference of the photoelectric cross section between the present calculation and XCOM database was 8% at a maximum (in 10keV for Be). The agreement tends to be better as the atomic number increases. The contribution from each atomic shell has a considerable discrepancy with XCOM database except for K-shell. However, because the photoelectric cross section arising from K-shell is dominant, the net photoelectric cross section was almost insensitive to the different handling in Fock potential. Conclusion: The photoelectric cross-section program has been developed based on the fully self-consistent relativistic HF atomic model. Due to small effect on the Fock
Energy Technology Data Exchange (ETDEWEB)
Manley, D.M.
1981-11-01
The doubly differential cross section d/sup 2/sigma/d..cap omega..dT for ..pi../sup +/ mesons produced in the reaction ..pi../sup -/p ..-->.. ..pi../sup +/..pi../sup -/n was measured at 203, 230, 256, and 358 MeV with a single-arm magnetic spectrometer. A set of five previous measurements at 254, 280, 292, 331, and 356 MeV was reanalyzed with the new measurements. Integrated cross sections were calculated for the combined data set with unprecedented accuracy for this energy range. The chiral-symmetry-breaking parameter was determined to be epsilon = -0.03 +- 0.26 by extrapolating the mean square modulus of the matrix element to threshold and comparing the threshold matrix element with the prediction of soft-pion theory. This value of epsilon is consistent with zero as required by the Weinberg Lagrangian. Measurements at the three highest energies were compared with the results of an isobar-model analysis of bubble-chamber events by an LBL-SLAC collaboration. After allowing for an overall normalization difference, the measurements at 331 and 358 MeV were in excellent agreement with the results of their analysis. The measurement at 292 MeV required variation of the PS11(epsilonN) amplitude, as well as the overall normalization, which could be due to the limited number of bubble-chamber events available for the LBL-SLAC analysis at this energy. A partial-wave analysis of the measurements was also carried out with the VPI isobar model. Within this model, the matrix element contains a background term calculated from a phenomenological ..pi..N Lagrangian that is consistent with the hypotheses of current algebra and PCAC. The reaction was found to be dominated by the initial P11 wave. Production of the ..delta.. isobar from initial D waves was found to be significant at the two highest energies.
Total cross-section at LHC from minijets and soft gluon resummation in the infrared region
Pancheri, G; Grau, A; Srivastava, Y N
2007-01-01
A model for total cross-sections incorporating QCD jet cross-sections and soft gluon resummation is described and compared with present data on $pp$ and ${\\bar p}p$ cross-sections. Predictions for LHC are presented for different parameter sets. It is shown that they differ according to the small x-behaviour of available parton density functions.
Xanthakis, Vanessa; Sullivan, Lisa M; Vasan, Ramachandran S
2013-12-10
Correlated data are obtained in longitudinal epidemiological studies, where repeated measurements are taken on individuals or groups over time. Such longitudinal data are ideally analyzed using multilevel modeling approaches, which appropriately account for the correlations in repeated responses in the same individual. Commonly used regression models are inappropriate as they assume that measurements are independent. In this tutorial, we use multilevel modeling to demonstrate its use for analysis of correlated data obtained from serial examinations on individuals. We focus on cardiovascular epidemiological research where investigators are often interested in quantifying the relations between clinical risk factors and outcome measures (X and Y, respectively), where X and Y are measured repeatedly over time, for example, using serial observations on participants attending multiple examinations in a longitudinal cohort study. For instance, it may be of interest to evaluate the relations between serial measures of left ventricular mass (outcome) and of its potential determinants (i.e., body mass index and blood pressure), both of which are measured over time. In this tutorial, we describe the application of multilevel modeling to cardiovascular risk factors and outcome data (using serial echocardiographic data as an example of an outcome). We suggest an analytical approach that can be implemented to evaluate relations between any potential outcome of interest and risk factors, including assessment of random effects and nonlinear relations. We illustrate these steps using echocardiographic data from the Framingham Heart Study with SAS PROC MIXED.
Sakumura, Joseph S.
Surveys of dental student values are described that were designed to assess value ratings by four dental classes in 1976, annual value ratings of a freshman class as they progressed through their four year program, and the usefulness of the cross-sectional design versus the longitudinal design. Each of the two surveys, which were conducted by the…
Total and ionization cross sections of electron scattering by fluorocarbons
Energy Technology Data Exchange (ETDEWEB)
Antony, B K [Department of Physics, Sardar Patel University, Vallabh Vidyanagar-388 120, Gujarat (India); Joshipura, K N [Department of Physics, Sardar Patel University, Vallabh Vidyanagar-388 120, Gujarat (India); Mason, N J [Department of Physics and Astronomy, Open University, Milton Keynes-MK7 6AA (United Kingdom)
2005-02-14
Electron impact total cross sections (50-2000 eV) and total ionization cross sections (threshold to 2000 eV) are calculated for typical plasma etching molecules CF{sub 4}, C{sub 2}F{sub 4}, C{sub 2}F{sub 6}, C{sub 3}F{sub 8} and CF{sub 3}I and the CF{sub x} (x 1-3) radicals. The total elastic and inelastic cross sections are determined in the spherical complex potential formalism. The sum of the two gives the total cross section and the total inelastic cross section is used to calculate the total ionization cross sections. The present total and ionization cross sections are found to be consistent with other theories and experimental measurements, where they exist. Our total cross section results for CF{sub x} (x = 1-3) radicals presented here are first estimates on these species.
Experiments on Antiprotons: Antiproton-Nucleon Cross Sections
Chamberlain, Owen; Keller, Donald V.; Mermond, Ronald; Segre, Emilio; Steiner, Herbert M.; Ypsilantis, Tom
1957-07-22
In this paper experiments are reported on annihilation and scattering of antiprotons in H{sub 2}O , D{sub 2}O, and O{sub 2}. From the data measured it is possible to obtain an antiproton-proton and an antiproton-deuteron cross section at 457 Mev (lab). Further analysis gives the p-p and p-n cross sections as 104 mb for the p-p reaction cross section and 113 mb for the p-n reaction cross section. The respective annihilation cross sections are 89 and 74 mb. The Glauber correction necessary in order to pass from the p-d to the p-n cross section by subtraction of the p-p cross section is unfortunately large and somewhat uncertain. The data are compared with the p-p and p-n cross sections and with other results on p-p collisions.
Simultaneous Evaluation of Fission Cross Sections for Cm Isotopes
Directory of Open Access Journals (Sweden)
Lee Y.-O.
2010-03-01
Full Text Available Fission Cross Sections for a complete set of Cm-isotopes, 240-250Cm, have been calculated in the incident energy range from above resonance region to 20 MeV. This work aims at providing the fission cross sections with consistent set of model parameters for Cm isotopes, as a part of a complete evaluation including covariance files for several minor actinides which play a great role in the Advanced Fuel Cycle (AFC design and applications as well as the design of new generation of nuclear reactors (GEN-IV. This was accomplished by means of computational analyses carried out with the nuclear model code EMPIRE-2.19 which is the modular system of nuclear reaction codes. A Fission model of this work took into account transmission derived in the WKB approximation within an optical model through a double-humped fission barrier.
Simultaneous Evaluation of Fission Cross Sections for Cm Isotopes
Kim, H. I.; Gil, C.-S.; Lee, Y.-O.
2010-03-01
Fission Cross Sections for a complete set of Cm-isotopes, 240-250Cm, have been calculated in the incident energy range from above resonance region to 20 MeV. This work aims at providing the fission cross sections with consistent set of model parameters for Cm isotopes, as a part of a complete evaluation including covariance files for several minor actinides which play a great role in the Advanced Fuel Cycle (AFC) design and applications as well as the design of new generation of nuclear reactors (GEN-IV). This was accomplished by means of computational analyses carried out with the nuclear model code EMPIRE-2.19 which is the modular system of nuclear reaction codes. A Fission model of this work took into account transmission derived in the WKB approximation within an optical model through a double-humped fission barrier.
Electron Elastic-Scattering Cross-Section Database
SRD 64 NIST Electron Elastic-Scattering Cross-Section Database (PC database, no charge) This database provides values of differential elastic-scattering cross sections, corresponding total elastic-scattering cross sections, phase shifts, and transport cross sections for elements with atomic numbers from 1 to 96 and for electron energies between 50 eV and 20,000 eV (in steps of 1 eV).
Top quark pair production cross section at the Tevatron
Energy Technology Data Exchange (ETDEWEB)
Cortiana, Giorgio; /INFN, Padua /Padua U.
2008-04-01
Top quark pair production cross section has been measured at the Tevatron by CDF and D0 collaborations using different channels and methods, in order to test standard model predictions, and to search for new physics hints affecting the t{bar t} production mechanism or decay. Measurements are carried out with an integrated luminosity of 1.0 to 2.0 fb{sup -1}, and are found to be consistent with standard model expectations.
Embleton, Lonnie; Ayuku, David; Kamanda, Allan; Atwoli, Lukoye; Ayaya, Samuel; Vreeman, Rachel; Nyandiko, Winstone; Gisore, Peter; Koech, Julius; Braitstein, Paula
2014-04-01
Sub-Saharan Africa is home to approximately 55 million orphaned children. The growing orphan crisis has overwhelmed many communities and has weakened the ability of extended families to meet traditional care-taking expectations. Other models of care and support have emerged in sub-Saharan Africa to address the growing orphan crisis, yet there is a lack of information on these models available in the literature. We applied a human rights framework using the United Nations Convention on the Rights of the Child to understand what extent children's basic human rights were being upheld in institutional vs. community- or family-based care settings in Uasin Gishu County, Kenya. The Orphaned and Separated Children's Assessments Related to their Health and Well-Being Project is a 5-year cohort of orphaned children and adolescents aged ≤18 year. This descriptive analysis was restricted to baseline data. Chi-Square test was used to test for associations between categorical /dichotomous variables. Fisher's exact test was also used if some cells had expected value of less than 5. Included in this analysis are data from 300 households, 19 Charitable Children's Institutions (CCIs) and 7 community-based organizations. In total, 2871 children were enrolled and had baseline assessments done: 1390 in CCI's and 1481 living in households in the community. We identified and described four broad models of care for orphaned and separated children, including: institutional care (sub-classified as 'Pure CCI' for those only providing residential care, 'CCI-Plus' for those providing both residential care and community-based supports to orphaned children , and 'CCI-Shelter' which are rescue, detention, or other short-term residential support), family-based care, community-based care and self-care. Children in institutional care (95%) were significantly (p children and uphold their rights. Family-based care plays an essential role; however, households require increased support to adequately
Cross-sectional test of the Fama-French three-factor model: Evidence from Bangladesh stock market
Hasan, Md. Zobaer; Kamil, Anton Abdulbasah
2014-09-01
Stock market is an important part of a country's economy. It supports the country's economic development and progress by encouraging the efficiency and profitability of firms. This research was designed to examine the risk-return association of companies in the Dhaka Stock Exchange (DSE) market of Bangladesh by using the Fama-French three-factor model structure. The model is based on three factors, which are stock beta, SMB (difference in returns of the portfolio with small market capitalisation minus that with big market capitalisation) and HML (difference in returns of the portfolio with high book-to-market ratio minus that with low book-to-market ratio). This study focused on the DSE market as it is one of the frontier emerging stock markets of South Asia. For this study, monthly stock returns from 71 non-financial companies were used for the period of January 2002 to December 2011. DSI Index was used as a proxy for the market portfolio and Bangladesh government 3-Month T-bill rate was used as the proxy for the risk-free asset. It was found that large capital stocks outperform small capital stocks and stocks with lower book-to-market ratios outperform stocks with higher book-to-market ratios in the context of Bangladesh stock market.
Finite sum expressions for elastic and reaction cross sections
Energy Technology Data Exchange (ETDEWEB)
Werneth, Charles M., E-mail: charles.m.werneth@nasa.gov [NASA Langley Research Center, 2 West Reid Street, Hampton, VA 23681 (United States); Maung, Khin Maung, E-mail: khin.maung@usm.edu [University of Southern Mississippi, Department of Physics and Astronomy, 118 College Drive, Box 5046, Hattiesburg, MS (United States); Mead, Lawrence R., E-mail: lawrence.mead@usm.edu [University of Southern Mississippi, Department of Physics and Astronomy, 118 College Drive, Box 5046, Hattiesburg, MS (United States); Blattnig, Steve R., E-mail: steve.r.blattnig@nasa.gov [NASA Langley Research Center, 2 West Reid Street, Hampton, VA 23681 (United States)
2013-08-01
Nuclear cross section calculations are often performed by using the partial wave method or the Eikonal method through Glauber theory. The expressions for the total cross section, total elastic cross section, and total reaction cross section in the partial wave method involve infinite sums and do not utilize simplifying approximations. Conversely, the Eikonal method gives these expressions in terms of integrals but utilizes the high energy and small angle approximations. In this paper, by using the fact that the lth partial wave component of the T-matrix can be very accurately approximated by its Born term, the infinite sums in each of the expressions for the differential cross section, total elastic cross section, total cross section, and total reaction cross section are re-written in terms of finite sums plus closed form expressions. The differential cross sections are compared to the Eikonal results for {sup 16}O+{sup 16}O,{sup 12}C+{sup 12}C, and p+{sup 12}C elastic scattering. Total cross sections, total reaction cross sections, and total elastic cross sections are compared to the Eikonal results for {sup 12}C+{sup 12}C scattering.
Directory of Open Access Journals (Sweden)
Chushnyakova Maria
2013-12-01
Full Text Available We performed quantitative theoretical analysis of the high precision data on the fusion excitation function in the reaction 16O + 144Sm involving spherical nuclei. For this purpose the model is developed in which the collision process is described by the stochastic dynamical equations with the retarding friction and colored noise. The friction force is supposed to be proportional to the squared derivative of nucleus-nucleus interaction potential. The latter is calculated within the framework of the double folding approach with the density-dependent M3Y NN-forces. Varying the radial dissipation strength KR and the matter diffuseness of 144Sm we reach χ2 per point equal to 5.4. However the values of KR and the friction retardation time τC appear to be strongly correlated. More high precision data are needed to make more definite conclusions about the values of KR and τC.
Chushnyakova, Maria; Gontchar, Igor
2013-12-01
We performed quantitative theoretical analysis of the high precision data on the fusion excitation function in the reaction 16O + 144Sm involving spherical nuclei. For this purpose the model is developed in which the collision process is described by the stochastic dynamical equations with the retarding friction and colored noise. The friction force is supposed to be proportional to the squared derivative of nucleus-nucleus interaction potential. The latter is calculated within the framework of the double folding approach with the density-dependent M3Y NN-forces. Varying the radial dissipation strength KR and the matter diffuseness of 144Sm we reach χ2 per point equal to 5.4. However the values of KR and the friction retardation time τC appear to be strongly correlated. More high precision data are needed to make more definite conclusions about the values of KR and τC.
Smith, Brandon D.; Boyd, Iain D.; Kamhawi, Hani
2014-01-01
The sensitivity of xenon ionization rates to collision cross-sections is studied within the framework of a hybrid-PIC model of a Hall thruster discharge. A revised curve fit based on the Drawin form is proposed and is shown to better reproduce the measured crosssections at high electron energies, with differences in the integrated rate coefficients being on the order of 10% for electron temperatures between 20 eV and 30 eV. The revised fit is implemented into HPHall and the updated model is used to simulate NASA's HiVHAc EDU2 Hall thruster at discharge voltages of 300, 400, and 500 V. For all three operating points, the revised cross-sections result in an increase in the predicted thrust and anode efficiency, reducing the error relative to experimental performance measurements. Electron temperature and ionization reaction rates are shown to follow the trends expected based on the integrated rate coefficients. The effects of triply-charged xenon are also assessed. The predicted thruster performance is found to have little or no dependence on the presence of triply-charged ions. The fraction of ion current carried by triply-charged ions is found to be on the order of 1% and increases slightly with increasing discharge voltage. The reaction rates for the 0?III, I?III, and II?III ionization reactions are found to be of similar order of magnitude and are about one order of magnitude smaller than the rate of 0?II ionization in the discharge channel.
Gangwar, Reetesh K.; Dipti; Srivastava, Rajesh; Stafford, Luc
2016-06-01
A collisional-radiative (C-R) model for krypton plasma using fully relativistic distorted-wave cross sections for electron excitations was developed. The model was applied to the characterization of inductively coupled Kr plasma with cylindrical geometry over the pressure regime 1-50 mTorr. Radially averaged emission intensities from transitions of Kr (4p55p → 4p55s) in the range 500-900 nm were recorded at 17 cm from the planar RF-driven coil, with the plasma operated in the inductive regime (H mode). The measured emission intensities were then fitted by varying the electron density, n e, and electron temperature, T e, in the C-R model. At both low and high pressures, variations of the electron density by over two orders of magnitude had only a minor role on the relative emission intensities. On the other hand, T e values deduced from the comparison between experiment and model decreased from 6.7 to 2.6 eV as pressure increased from 1 to 50 mTorr. These results are found to be in good agreement with the effective electron temperature determined from Langmuir probe measurements and the predictions of a model based on the particle balance equation of charged particles.
Flores-Bustamante, Mario C.; Rosete-Aguilar, Martha; Calixto, Sergio
2016-03-01
A lens containing a liquid medium and having at least one elastic membrane as one of its components is known as an elastic membrane lens (EML). The elastic membrane may have a constant or variable thickness. The optical properties of the EML change by modifying the profile of its elastic membrane(s). The EML formed of elastic constant thickness membrane(s) have been studied extensively. However, EML information using elastic membrane of variable thickness is limited. In this work, we present simulation results of the mechanical and optical behavior of two EML with variable thickness membranes (convex-plane membranes). The profile of its surfaces were modified by liquid medium volume increases. The model of the convex-plane membranes, as well as the simulation of its mechanical behavior, were performed using Solidworks® software; and surface's points of the deformed elastic lens were obtained. Experimental stress-strain data, obtained from a silicone rubber simple tensile test, according to ASTM D638 norm, were used in the simulation. Algebraic expressions, (Schwarzschild formula, up to four deformation coefficients, in a cylindrical coordinate system (r, z)), of the meridional profiles of the first and second surfaces of the deformed convex-plane membranes, were obtained using the results from Solidworks® and a program in the software Mathematica®. The optical performance of the EML was obtained by simulation using the software OSLO® and the algebraic expressions obtained in Mathematica®.
Influence of the target excitations on neutron cross section calculations
Energy Technology Data Exchange (ETDEWEB)
Cabezas, R.; Lubian, J. [Center for Applied Studies to Nuclear Development, Havana (Cuba)
1994-12-31
Considerable progress has been made in the use of the nuclear models and methods to derive physically meaningful parameters for model calculations. In this sense, we analyze the influence of the collective modes of excitation of the target nucleus on the cross section calculations in some medium atomic-weight nuclei, where spectroscopic studies show evidence of anharmonic vibrations, nonaxial deformations and so on. Coupled channel calculations for low-energy neutron inelastic scattering to collective states in {sup 48}Ti, {sup 54}Cr and {sup 62}Ni isotopes are made using the Davydov-Chaban model (DCM). It is shown, that the consideration of the structural features of the target nucleus excitation in the cross section calculations guarantees the agreement with the experimental measurements.
Developing Scientific Reasoning Through Drawing Cross-Sections
Hannula, K. A.
2012-12-01
Cross-sections and 3D models of subsurface geology are typically based on incomplete information (whether surface geologic mapping, well logs, or geophysical data). Creating and evaluating those models requires spatial and quantitative thinking skills (including penetrative thinking, understanding of horizontality, mental rotation and animation, and scaling). However, evaluating the reasonableness of a cross-section or 3D structural model also requires consideration of multiple possible geometries and geologic histories. Teaching students to create good models requires application of the scientific methods of the geosciences (such as evaluation of multiple hypotheses and combining evidence from multiple techniques). Teaching these critical thinking skills, especially combined with teaching spatial thinking skills, is challenging. My Structural Geology and Advanced Structural Geology courses have taken two different approaches to developing both the abilities to visualize and to test multiple models. In the final project in Structural Geology (a 3rd year course with a pre-requisite sophomore mapping course), students create a viable cross-section across part of the Wyoming thrust belt by hand, based on a published 1:62,500 geologic map. The cross-section must meet a number of geometric criteria (such as the template constraint), but is not required to balance. Each student tries many potential geometries while trying to find a viable solution. In most cases, the students don't visualize the implications of the geometries that they try, but have to draw them and then erase their work if it does not meet the criteria for validity. The Advanced Structural Geology course used Midland Valley's Move suite to test the cross-sections that they made in Structural Geology, mostly using the flexural slip unfolding algorithm and testing whether the resulting line lengths balanced. In both exercises, students seemed more confident in the quality of their cross-sections when the
KAERI charged particle cross section library for radioisotope production
Chang, J H; Kim, D H; Lee, Y O; Zhuang, Y X
2001-01-01
This report summarized information and figures describing the 'KAERI Charged Particle Cross Section Library for Radioisotope production' The library contains proton-, deutron-, He-3-, and alpha-induced monitor cross sections, and gamma- and positron-emitter production cross sections. Experimental data and evaluation methods are described, and the evaluated cross sections are compared with those of the IAEA, MENDL, and LA150. The library has cross sections and emission spectra suitable for the transport analysis in the design of radioisotope production system, and are available at http://atom.kaeri.re.kr/ in ENDF-6 format.
Coulomb and nuclear effects in breakup and reaction cross sections
Descouvemont, Pierre; Hussein, Mahir S
2016-01-01
We use a three-body Continuum Discretized Coupled Channel (CDCC) model to investigate Coulomb and nuclear effects in breakup and reaction cross sections. The breakup of the projectile is simulated by a finite number of square integrable wave functions. First we show that the scattering matrices can be split in a nuclear term, and in a Coulomb term. This decomposition is based on the Lippmann-Schwinger equation, and requires the scattering wave functions. We present two different methods to separate both effects. Then, we apply this separation to breakup and reaction cross sections of 7Li + 208Pb. For breakup, we investigate various aspects, such as the role of the alpha + t continuum, the angular-momentum distribution, and the balance between Coulomb and nuclear effects. We show that there is a large ambiguity in defining the 'Coulomb' and 'nuclear' breakup cross sections, since both techniques, although providing the same total breakup cross sections, strongly differ for the individual components. We suggest...
Electron-silane scattering cross section for plasma assisted processes
Verma, Pankaj; Kaur, Jaspreet; Antony, Bobby
2017-03-01
Silane is an important molecule with numerous applications to natural and technological plasmas. In such environments, where plasma assisted processes are vital, electron induced reactions play a major role in its chemistry. In view of this, electron induced scattering of molecules such as silane finds significance. This article reports a comprehensive study of electron impact cross sections for silane over a wide energy range. In particular, the emphasis is given in providing a complete dataset for various electron scattering events possible with silane. Such dataset is the need for the plasma modeling community. Moreover, literature survey shows that the cross section database for silane is fragmentary. To fill this void, we have computed the differential elastic, total, rotational excitation, and momentum transfer cross sections. Two formalisms that are reliable in their energy domain are employed to accomplish the task: the R-matrix method through QUANTEMOL-N at low incident energies and the spherical complex optical potential formalism at intermediate to high energies. Interestingly, the comparison of the present cross section exhibits a good concurrence with the previous data, wherever available.
[Fast neutron cross section measurements]. Progress report
Energy Technology Data Exchange (ETDEWEB)
Knoll, G.F.
1992-10-26
From its inception, the Nuclear Data Project at the University of Michigan has concentrated on two major objectives: (1) to carry out carefully controlled nuclear measurements of the highest possible reliability in support of the national nuclear data program, and (2) to provide an educational opportunity for students with interests in experimental nuclear science. The project has undergone a successful transition from a primary dependence on our photoneutron laboratory to one in which our current research is entirely based on a unique pulsed 14 MeV fast neutron facility. The new experimental facility is unique in its ability to provide nanosecond bursts of 14 MeV neutrons under conditions that are ``clean`` and as scatter-free as possible, and is the only one of its type currently in operation in the United States. It has been designed and put into operation primarily by graduate students, and has met or exceeded all of its important initial performance goals. We have reached the point of its routine operation, and most of the data are now in hand that will serve as the basis for the first two doctoral dissertations to be written by participating graduate students. Our initial results on double differential neutron cross sections will be presented at the May 1993 Fusion Reactor Technology Workshop. We are pleased to report that, after investing several years in equipment assembly and optimization, the project has now entered its ``data production`` phase.
Resonance capture cross section of 207Pb
Domingo-Pardo, C; Aerts, G; Alvarez-Pol, H; Alvarez-Velarde, F; Andrzejewski, J; Andriamonje, Samuel A; Assimakopoulos, P A; Audouin, L; Badurek, G; Baumann, P; Becvar, F; Berthoumieux, E; Bisterzo, S; Calviño, F; Cano-Ott, D; Capote, R; Carrapico, C; Chepel, V; Cennini, P; Chiaveri, Enrico; Colonna, N; Cortés, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillman, I; Dolfini, R; Dridi, W; Durán, I; Eleftheriadis, C; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Fitzpatrick, L; Frais-Kölbl, H; Fujii, K; Furman, W; Gallino, R; Gonçalves, I; González-Romero, E M; Goverdovski, A; Gramegna, F; Griesmayer, E; Guerrero, C; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martínez, A; Igashira, M; Isaev, S; Jericha, E; Kadi, Y; Käppeler, F K; Karamanis, D; Karadimos, D; Kerveno, M; Ketlerov, V; Köhler, P; Konovalov, V; Kossionides, E; Krticka, M; Lamboudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Mastinu, P; Mengoni, A; Milazzo, P M; Moreau, C; Mosconi, M; Neves, F; Oberhummer, Heinz; Oshima, M; O'Brien, S; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Plag, R; Plompen, A; Plukis, A; Poch, A; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rosetti, M; Rubbia, Carlo; Rudolf, G; Rullhusen, P; Salgado, J; Sarchiapone, L; Savvidis, I; Stéphan, C; Tagliente, G; Taín, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A; Villamarín, D; Vincente6, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wendler, H; Wiescher, M; Wisshak, K
2006-01-01
The radiative neutron capture cross section of 207Pb has been measured at the CERN neutron time of flight installation n_TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters and radiative kernels have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77(8)% to the solar abundance of 207Pb. This corresponds to an r-process component of 23(8)%, which is important for deriving the U/Th ages of metal poor halo stars.
Energy Technology Data Exchange (ETDEWEB)
Kaufmann, O.; Martin, T. [Service de Geologie Fondamentale et Appliquee, Mons (Belgium)
2009-01-15
In a wide range of applications involving geological modelling, geological data available at low cost usually consist of documents such as cross-sections or geological maps and punctual data like borehole logs or outcrop descriptions. In order to build accurate 3D geological models based on this information, it is necessary to develop a methodology that takes into account the variety of available data. Such models, of the geometry of geological bodies, should also be easy to edit and update to integrate new data. This kind of model should produce a consistent representation of subsurface geology that may be a support for modelling other subsoil characteristics such as hydrogeologic or geothermic properties of the geological bodies. This paper presents a methodology developed to process geological information in this context. The aims of this methodology are comprehensive data description, effective data validation and easier model updates. Thus, special attention has been given to data structures and processing flows. The adopted methodology is implemented on a system architecture formed by a geographic information system, a geomodeler and a database communicating by file transfers. An application of this methodology, to build a 3D geological model of the subsoil over former coalmines used to store natural gas, is then presented. This model integrates the geological information available and is representative of the geological context. It is a support to the environmental follow-up needed after the end of gas-storage operations. This is a correction from the paper in the March 2008 issue (volume 34, part 3, pages 278-290).
Institute of Scientific and Technical Information of China (English)
Zafar Yasin
2009-01-01
A new method is used to compute the fission cross sections in which a change of the ratio of the level density parameter in fission to neutron emission channels is taken into account with the change of the incident energy of the projectile.It is shown that fission cross sections induced by nucleons and pions depend on the ratio of the level density parameter in the fission and evaporation modes,i.e.αf/αn,respectively.We are unable to describe well the cross sections for fission without using this new method.The computed values exhibit reasonable agreement with the experimental data found in the literature across a wide range of beam energies.
Directory of Open Access Journals (Sweden)
Brambs Hans
2011-04-01
Full Text Available Abstract Background Systematic aerobe training has positive effects on the compliance of dedicated arterial walls. The adaptations of the arterial structure and function are associated with the blood flow-induced changes of the wall shear stress which induced vascular remodelling via nitric oxide delivered from the endothelial cell. In order to assess functional changes of the common carotid artery over time in these processes, a precise measurement technique is necessary. Before this study, a reliable, precise, and quick method to perform this work is not present. Methods We propose a fully automated algorithm to analyze the cross-sectional area of the carotid artery in MR image sequences. It contains two phases: (1 position detection of the carotid artery, (2 accurate boundary identification of the carotid artery. In the first phase, we use intensity, area size and shape as features to discriminate the carotid artery from other tissues and vessels. In the second phase, the directional gradient, Hough transform, and circle model guided dynamic programming are used to identify the boundary accurately. Results We test the system stability using contrast degraded images (contrast resolutions range from 50% to 90%. The unsigned error ranges from 2.86% ± 2.24% to 3.03% ± 2.40%. The test of noise degraded images (SNRs range from 16 to 20 dB shows the unsigned error ranging from 2.63% ± 2.06% to 3.12% ± 2.11%. The test of raw images has an unsigned error 2.56% ± 2.10% compared to the manual tracings. Conclusions We have proposed an automated system which is able to detect carotid artery cross sectional boundary in MRI sequences during heart cycles. The accuracy reaches 2.56% ± 2.10% compared to the manual tracings. The system is stable, reliable and results are reproducible.
Infrared Gluon Resummation and pp total cross-sections
Pancheri, Giulia; Grau, A; Shekhovtsova, O; Srivastava, Yogendra N
2014-01-01
We address here the problem of describing both the total and the elastic proton-proton cross-section, through the four outstanding features of hadron scattering: (i) the optical point; (ii) the forward peak, (iii) the dip and (iv) the subsequent descent at larger momentum transfers. These issues are discussed through an eikonal model for the elastic amplitude where the matter distribution in impact parameter space is given by resummed soft gluons down into the infrared (IR) region. The asymptotic growth of the total cross-section is obtained in a mini-jet model and the taming (saturation) at high energies is related to confinement realized here through an IR singular strong coupling constant alpha_s(Q^2). We present an ansatz that links the IR singularity of alpha_s(Q^2) to that of asymptotic freedom (AF) (at lowest order). Through this model, we illustrate the problems that arise in a generic one-channel eikonal model employed for a description of the measured differential elastic cross-section at LHC7.
Kamionkowski, Marc; Profumo, Stefano
2008-12-31
Recent studies have considered modifications to the standard weakly interacting massive particle scenario in which the pair annihilation cross section (times relative velocity v) is enhanced by a factor 1/upsilon to approximately 10(-3) in the Galaxy, enough to explain several puzzling Galactic radiation signals. We show that in these scenarios a burst of weakly interacting massive particle annihilation occurs in the first collapsed dark-matter halos. We show that severe constraints to the annihilation cross section derive from measurements of the diffuse extragalactic radiation and from ionization and heating of the intergalactic medium.
NURSE STAFFING AND MEDICATION ERRORS: CROSS SECTIONAL OR LONGITUDINAL RELATIONSHIPS?
2009-01-01
We used autoregressive latent trajectory (ALT) modeling to examine the relationship between change in nurse staffing and change in medication errors over 6 months in 284 general medical-surgical nursing units. We also investigated the impact of select hospital and nursing unit characteristics on the baseline level and rate of change in medication errors. We found essentially no support for a nurse staffing – medication error relationship either cross-sectionally or longitudinally. Few hospita...
Jawad, Mohammed; Roderick, Paul
2017-05-01
Waterpipe smoking is more prevalent than cigarette smoking among adolescents in the Eastern Mediterranean Region (EMR); however, simple prevalence masks complex waterpipe smoking patterns and makes uncertain its contribution to risk of tobacco-related harm. This study aimed to integrate the impact of cigarette and waterpipe tobacco use on toxicant exposure among EMR adolescents. A cross-sectional model made equivalent individual-level toxicant exposure data for cigarettes and waterpipes, and aggregated it to 23 countries in the EMR using the Global Youth Tobacco Survey. The waterpipe model adjusted for estimated frequency of use, session duration and sharing behaviours. The final model included 60 306 12-17-year olds, and modelled as outcomes nicotine, carbon monoxide (CO) and 14 carcinogens. Sensitivity analyses substantially reduced session duration and proportion of solo use. Our model suggests waterpipe use may contribute a median of 36.4% (IQR 26.7-46.8%, n=16) of the total toxicant exposure from tobacco, and may reach up to 73.5% and 71.9% of total CO and benzene exposure, respectively. Sensitivity analyses reduced all values by 4.3-21.0%, but even the most conservative scenarios suggested over 50% of benzene and CO exposure was from waterpipe use. Between 69.2% and 73.5% of total toxicant exposure derived from dual cigarette and waterpipe users, who smoked cigarettes and waterpipe more frequently and intensely than single users. More research is warranted to refine our model's parameters. Tobacco control researchers should consider a move towards a single unit of measure for cigarette and waterpipe tobacco exposure in order to better inform health policy. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
Absolute cross sections for charge capture from Rydberg targets by slow highly charged ions
Energy Technology Data Exchange (ETDEWEB)
DePaola, B.D.; Huang, M.; Winecki, S.; Stoeckli, M.P.; Kanai, Y. [J. R. Macdonald Laboratory, Kansas State University, Manhattan, Kansas 66506 (United States); Lundeen, S.R.; Fehrenbach, C.W.; Arko, S.A. [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)
1995-09-01
A crossed beam experiment has been used to measure absolute charge capture cross sections in collisions of slow highly charged xenon ions with laser excited Rydberg atoms. The cross sections were measured for scaled projectile velocities {ital nv}{sub {ital p}} from 1.0 to 6.0, for projectile charges of 8, 16, 32, and 40, where {ital n} is the principal quantum number of the target electron. Experimental cross sections are compared with predictions of classical models.
Handbook of LHC Higgs Cross Sections: 3. Higgs Properties
Energy Technology Data Exchange (ETDEWEB)
Heinemeyer, S; et al.
2013-01-01
This Report summarizes the results of the activities in 2012 and the first half of 2013 of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. This report follows the first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) and the second working group report Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002). After the discovery of a Higgs boson at the LHC in mid-2012 this report focuses on refined prediction of Standard Model (SM) Higgs phenomenology around the experimentally observed value of 125-126 GeV, refined predictions for heavy SM-like Higgs bosons as well as predictions in the Minimal Supersymmetric Standard Model and first steps to go beyond these models. The other main focus is on the extraction of the characteristics and properties of the newly discovered particle such as couplings to SM particles, spin and CP-quantum numbers etc.
Institute of Scientific and Technical Information of China (English)
彭斌; 张俊辉; 谢小正; 龚海峰
2016-01-01
为了详细研究变截面涡旋压缩机的性能特点，考虑到腔体工作过程中的压缩与排气，对涡旋压缩机传热的数学模型的设计及仿真计算与性能进行分析，建立基于质量守恒，能量守恒和实际气体状态方程的涡旋压缩机模型，得到了每个工作腔的传热量随曲轴转角的变化特性，分析了内传热特性和泄露对各个工作腔中温度、压力和质量的影响，进而揭示了传热、泄露特性与工作腔压力和温度变化的复杂关系。采用研制开发的变截面空气涡旋压缩机建立测试平台，并将模拟计算得到的排气温度、质量流量和轴功率与试验数据进行对比，证明该数学模型可以全面反映变截面涡旋压缩机从吸气到排气等完整过程，为制冷涡旋压缩机的性能分析和优化设计提供了理论依据。%In order to study the performance characteristics of variable cross-section scrol compressor in detail, considering the compression and exhaust in the process of the cavity operation, the design and simulation of its mathematical model and its heat transfer performance are analyzed, based on the conservation of mass,conservation of energy and the real gas state equation the model of the scrol compressor is established to get the heat transfer variable, characteristics with the crank angle of each working chamber,and the internal heat transfer characteristics and the influence of the leakage on its temperature, pressure and mass are analyzed to reveal the complex relationship between the heat transfer, leakage characteristics and working chamber pressure and temperature change. The developed variable cross-section air scrol compressor is taken as a working test platform to simutate and calculate the exhaust temperature,mass flow shaft power which are compared with the experimental data. The model can reflect the complete process of the scrol compressor with variable cross-sections from the suction to
Asaturyan, R; Mkrtchyan, H; Navasardyan, T; Tadevosyan, V; Adams, G S; Ahmidouch, A; Angelescu, T; Arrington, J; Asaturyan, A; Baker, O K; Benmouna, N; Bertoncini, C; Blok, H P; Boeglin, W U; Bosted, P E; Breuer, H; Christy, M E; Connell, S H; Cui, Y; Dalton, M M; Danagoulian, S; Day, D; Dunne, J A; Dutta, D; Khayari, N El; Fenker, H C; Frolov, V V; Gan, L; Gaskell, D; Hafidi, K; Hinton, W; Holt, R J; Horn, T; Huber, G M; Hungerford, E; Jiang, X; Jones, M; Joo, K; Kalantarians, N; Kelly, J J; Keppel, C E; Kubarovsky, V; Li, Y; Liang, Y; Mack, D; Malace, S P; Markowitz, P; McGrath, E; McKee, P; Meekins, D G; Mkrtchyan, A; Moziak, B; Niculescu, G; Niculescu, I; Opper, A K; Ostapenko, T; Reimer, P E; Reinhold, J; Roche, J; Rock, S E; Schulte, E; Segbefia, E; Smith, C; Smith, G R; Stoler, P; Tang, L; Ungaro, M; Uzzle, A; Vidakovic, S; Villano, A; Vulcan, W F; Wang, M; Warren, G; Wesselmann, F R; Wojtsekhowski, B; Wood, S A; Xu, C; Yuan, L; Zheng, X
2011-01-01
A large set of cross sections for semi-inclusive electroproduction of charged pions (pi+-) from both proton and deuteron targets was measured. The data are in the deep-inelastic scattering region with invariant mass squared W2 > 4 GeV2 and range in four-momentum transfer squared 2 pion production mechanisms. The x, z and Pt2 dependences of several ratios (the ratios of favored-unfavored fragmentation functions, charged pion ratios, deuteron-hydrogen and aluminum-deuteron ratios for pi+ and pi-) have been studied. The ratios are found to be in good agreement with expectations based upon a high-energy quark-parton model description. We find the azimuthal dependences to be small, as compared to exclusive pion electroproduction, and consistent with theoretical expectations based on tree-level factorization in terms of transverse-momentum-dependent parton distribution and fragmentation functions. In the con text of a simple model, the initial transverse momenta of d quarks are found to be slightly smaller than for...
Directory of Open Access Journals (Sweden)
Jinzhu Zhao
Full Text Available BACKGROUND: HIV infection related to commercial sexual contact is a serious public health issue in China. The objectives of the present study are to explore the predictors of condom use among female sex workers (FSWs in China and examine the relationship between Health Belief Model (HBM constructs. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional study was conducted in two cities (Wuhan and Suizhou in Hubei Province, China, between July 2009 and June 2010. A total of 427 FSWs were recruited through mediators from the 'low-tier' entertainment establishments. Data were obtained by self-administered questionnaires. Structural equation models were constructed to examine the association. We collected 363 valid questionnaires. Within the context of HBM, perceived severity of HIV mediated through perceived benefits of condom use had a weak effect on condom use (r=0.07. Perceived benefits and perceived barriers were proximate determinants of condom use (r=0.23 and r=-0.62, respectively. Self-efficacy had a direct effect on perceived severity, perceived benefits, and perceived barriers, which was indirectly associated with condom use behaviors (r=0.36. CONCLUSIONS/SIGNIFICANCE: The HBM provides a useful framework for investigating predictors of condom use behaviors among FSWs. Future HIV prevention interventions should focus on increasing perceived benefits of condom use, reducing barriers to condoms use, and improving self-efficacy among FSWs.
Effects of cross-section on mechanical properties of Au nanowire
Energy Technology Data Exchange (ETDEWEB)
Vazinishayan, Ali; Yang, Shuming, E-mail: shuming.yang@mail.xjtu.edu.cn; Duongthipthewa, Anchalee; Wang, Yiming [State Key Laboratory for manufacturing system engineering, Xi’an Jiaotong University, Xi’an, 710049 (China)
2016-02-15
The aim of this paper is study of the effects of multiple cross-section of Au nanowire on mechanical properties. Different cross-section models of Au nanowires including circular, hexagonal, pentagonal and rectangular were simulated by finite element modeling using ABAQUS. In this study, the bending technique was applied so that both ends of the model were clamped with mid-span under loading condition. The cross-sections had the length of 400 nm and the diameter of 40 nm, except the circular cross-section while the rest of the cross-sections had an equivalent diameter. Von Misses stresses distribution were used to define the stress distribution in the cross-section under loading condition, and elastic deformation was analyzed by the beam theory. The results disclosed that the circular and the rectangular models had highest and lowest strengths against plastic deformation, respectively.
Asymptotic Behaviour of Pion--Pion Total Cross--Sections
Greynat, David; Vulvert, Grégory
2014-01-01
We derive a sum rule which shows an inconsistency between the Lukaszuk-Martin coefficient of the Froissart-Martin bound and well known properties of $\\pi\\pi$ amplitudes in QCD. We next compute the total cross sections for $\\pi^+ \\pi^-$, $\\pi^{\\pm} \\pi^0$ and $\\pi^0 \\pi^0$ scattering within the framework of the constituent chiral quark model (C$\\chi$QM) in the limit of a large number of colours $\\mathrm{N_c}$ and discuss their asymptotic behaviours. The same $\\pi\\pi$ cross sections are also discussed within the general framework of Large-$\\mathrm{N_c}$ QCD and we show that it is possible to make an Ansatz for the isospin $I=1$ and $I=0$ spectrum which satisfy the Froissart-Martin bound with coefficients which, contrary to the Lukaszuk-Martin coefficient, are not singular in the chiral limit and have the correct Large-$\\mathrm{N_c}$ counting. We finally propose a simple phenomenological model which matches the low energy behaviours of the $\\sigma_{\\pi^{\\pm}\\pi^0}^{\\rm total}(s)$ cross section predicted by the C...
Reconciling cross-sectional with longitudinal observations on annual decline.
Vollmer, W M
1993-01-01
In summary, numerous factors may contribute to observed differences between longitudinally and cross-sectionally derived measures of annual decline in lung function. The direction and magnitude of these differences appear hard to predict. Furthermore, although these differences can be minimized by careful modeling of the data, they cannot, in general, be completely avoided. It seems plausible, however, that both types of studies should give similar qualitative comparisons of risk factor effects if appropriately modeled. Longitudinal studies are likely to provide the most accurate and reliable estimates of lung function decline for both individuals and populations. Such data may be especially useful in identifying individuals with accelerated declines in lung function but who still have "normal" lung function as measured cross-sectionally. However, such studies require careful attention to quality control and typically require at least 4 years of follow-up before the noise in the data settles down. Multiple measurements, preferably four or more, are also necessary to reliably detect and adjust for survey effects. Cross-sectional studies, on the other hand, are simpler, cheaper, and quicker to conduct than are longitudinal studies. They may be particularly useful as a screening tool for identifying potentially affected or high-risk subjects (e.g., those with low levels of lung function) who may require further medical follow-up and/or ongoing monitoring. Both types of studies have a role in population-based occupational health hazard assessments.
Directory of Open Access Journals (Sweden)
Stefan Markun
Full Text Available AIMS: The aim of the study was to assess the concordance of care for age related macular degeneration with the evidence-based framework for care for chronic medical conditions known as the chronic care model. Furthermore we aimed to identify factors associated with the concordance of care with the chronic care model. METHODS: Multi-centered cross-sectional study. 169 patients beginning medical treatment for age related macular degeneration were recruited and analyzed. Patients completed the Patient Assessment of Chronic Illness Care (PACIC questionnaire, reflecting accordance to the chronic care model from a patient's perspective, the National Eye Institute Visual Functioning Questionnaire-25 (NEI-VFQ-25 and Patient Health Questionnaire (PHQ-9. Visual acuity and chronic medical conditions were assessed. Nonparametric tests and correlation analyses were performed, also multivariable regression analysis. RESULTS: The median PACIC summary score was 2.4 (interquartile range 1.75 to 3.25, the lowest PACIC subscale score was "follow-up/coordination" with a median of 1.8 (interquartile range 1.00 to 2.60. In multivariable regression analysis the presence of diabetes type 2 was strongly associated with low PACIC scores (coefficient = -0.85, p = 0.007. CONCLUSION: Generally, care for patients with age related macular degeneration by ophthalmologists is in moderate concordance with the chronic care model. Concerning follow-up and coordination of health service, large improvements are possible. Future research should answer the question how healthcare delivery can be improved effecting relevant benefits to patients with AMD.
Deuterium target data and precision neutrino-nucleus cross sections
Meyer, Aaron S; Gran, Richard; Hill, Richard J
2016-01-01
Amplitudes derived from scattering data on elementary targets are basic inputs to neutrino-nucleus cross section predictions. A prominent example is the isovector axial nucleon form factor, $F_A(q^2)$, which controls charged current signal processes at accelerator-based neutrino oscillation experiments. Previous extractions of $F_A$ from neutrino-deuteron scattering data rely on a dipole shape assumption that introduces an unquantified error. A new analysis of world data for neutrino-deuteron scattering is performed using a model-independent, and systematically improvable, representation of $F_A$. A complete error budget for the nucleon isovector axial radius leads to $r_A^2=0.46(22) \\,{\\rm fm}^2$, with a much larger uncertainty than determined in the original analyses. The quasielastic neutrino-neutron cross section is determined as $\\sigma(\
Cross-Section Measurements with the Radioactive Isotope Accelerator (RIA)
Energy Technology Data Exchange (ETDEWEB)
Stoyer, M A; Moody, K J; Wild, J F; Patin, J B; Shaughnessy, D A; Stoyer, N J; Harris, L J
2002-11-19
RIA will produce beams of exotic nuclei of unprecedented luminosity. Preliminary studies of the feasibility of measuring cross-sections of interest to the science based stockpile stewardship (SBSS) program will be presented, and several experimental techniques will be discussed. Cross-section modeling attempts for the A = 95 mass region will be shown. In addition, several radioactive isotopes could be collected for target production or medical isotope purposes while the main in-beam experiments are running. The inclusion of a broad range mass analyzer (BRAMA) capability at RIA will enable more effective utilization of the facility, enabling the performance of multiple experiments at the same time. This option will be briefly discussed.
Carbon Fragmentation Cross Sections for Hadrontherapy and Space Radiation Protection
De Napoli, M.; Agodi, C.; Cirrone, G. A. P.; Cuttone, G.; Nicolosi, D.; Pandola, L.; Raciti, G.; Romano, F.; Sardina, D.; Scuderi, V.; Tropea, S.; Bondì, M.; Cappuzzello, F.; Carbone, D.; Cavallaro, M.
2014-05-01
Fragmentation reactions represent a serious complication in hadrontherapy and space radiation protection. In order to predict their effects, both reliable Monte Carlo codes and experimental data are needed. The shortage of precise measurements, especially of double differential cross sections, has triggered many dedicated experiments at relativistic energies. Aiming to explore the Fermi energy regime, as well, where different reaction mechanisms are involved, we measured the 12C fragmentation at 62 AMeV on a 12C and a 197Au target. A high granularity Si-CsI hodoscope allowed to identify the charge and the mass of detected fragments and measure their energy and emission angle. In this work we report the double differential cross sections for the production of different fragments as a function of the emission angle. Experimental results are compared with the GEANT-4 Monte Carlo predictions performed using two reaction models, the Quantum Molecular Dynamic and the Binary Light Ion Cascade.
Elastic breakup cross sections of well-bound nucleons
Wimmer, K; Gade, A; Tostevin, J A; Baugher, T; Chajecki, Z; Coupland, D; Famiano, M A; Ghosh, T K; Howard, G F Grinyer M E; Kilburn, M; Lynch, W G; Manning, B; Meierbachtol, K; Quarterman, P; Ratkiewicz, A; Sanetullaev, A; Showalter, R H; Stroberg, S R; Tsang, M B; Weisshaar, D; Winkelbauer, J; Winkler, R; Youngs, M
2014-01-01
The 9Be(28Mg,27Na) one-proton removal reaction with a large proton separation energy of Sp(28Mg)=16.79 MeV is studied at intermediate beam energy. Coincidences of the bound 27Na residues with protons and other light charged particles are measured. These data are analyzed to determine the percentage contributions to the proton removal cross section from the elastic and inelastic nucleon removal mechanisms. These deduced contributions are compared with the eikonal reaction model predictions and with the previously measured data for reactions involving the re- moval of more weakly-bound protons from lighter nuclei. The role of transitions of the proton between different bound single-particle configurations upon the elastic breakup cross section is also quantified in this well-bound case. The measured and calculated elastic breakup fractions are found to be in good agreement.
Heinemeyer, S; Passarino, G; Tanaka, R; Andersen, J R; Artoisenet, P; Bagnaschi, E A; Banfi, A; Becher, T; Bernlochner, F U; Bolognesi, S; Bolzoni, P; Boughezal, R; Buarque, D; Campbell, J; Caola, F; Carena, M; Cascioli, F; Chanon, N; Cheng, T; Choi, S Y; David, A; de Aquino, P; Degrassi, G; Del Re, D; Denner, A; van Deurzen, H; Diglio, S; Di Micco, B; Di Nardo, R; Dittmaier, S; Dührssen, M; Ellis, R K; Ferrera, G; Fidanza, N; Flechl, M; de Florian, D; Forte, S; Frederix, R; Frixione, S; Gangal, S; Gao, Y; Garzelli, M V; Gillberg, D; Govoni, P; Grazzini, M; Greiner, N; Griffiths, J; Gritsan, A V; Grojean, C; Hall, D C; Hays, C; Harlander, R; Hernandez-Pinto, R; Höche, S; Huston, J; Jubb, T; Kadastik, M; Kallweit, S; Kardos, A; Kashif, L; Kauer, N; Kim, H; Klees, R; Krämer, M; Krauss, F; Laureys, A; Laurila, S; Lehti, S; Li, Q; Liebler, S; Liu, X; Logan, E; Luisoni, G; Malberti, M; Maltoni, F; Mawatari, K; Maierhoefer, F; Mantler, H; Martin, S; Mastrolia, P; Mattelaer, O; Mazzitelli, J; Mellado, B; Melnikov, K; Meridiani, P; Miller, D J; Mirabella, E; Moch, S O; Monni, P; Moretti, N; Mück, A; Mühlleitner, M; Musella, P; Nason, P; Neu, C; Neubert, M; Oleari, C; Olsen, J; Ossola, G; Peraro, T; Peters, K; Petriello, F; Piacquadio, G; Potter, C T; Pozzorini, S; Prokofiev, K; Puljak, I; Rauch, M; Rebuzzi, D; Reina, L; Rietkerk, R; Rizzi, A; Rotstein-Habarnau, Y; Salam, G P; Sborlini, G; Schissler, F; Schönherr, M; Schulze, M; Schumacher, M; Siegert, F; Slavich, P; Smillie, J M; Stål, O; von Soden-Fraunhofen, J F; Spira, M; Stewart, I W; Tackmann, F J; Taylor, P T E; Tommasini, D; Thompson, J; Thorne, R S; Torrielli, P; Tramontano, F; Tran, N V; Trócsányi, Z; Ubiali, M; Vazquez Acosta, M; Vickey, T; Vicini, A; Waalewijn, W J; Wackeroth, D; Wagner, C; Walsh, J R; Wang, J; Weiglein, G; Whitbeck, A; Williams, C; Yu, J; Zanderighi, G; Zanetti, M; Zaro, M; Zerwas, P M; Zhang, C; Zirke, T J E; Zuberi, S
2013-01-01
This Report summarizes the results of the activities in 2012 and the first half of 2013 of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. This report follows the first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) and the second working group report Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002). After the discovery of a Higgs boson at the LHC in mid-2012 this report focuses on refined prediction of Standard Model (SM) Higgs phenomenology around the experimentally observed value of 125-126 GeV, refined predictions for heavy SM-like Higgs bosons as well as predictions in the Minimal Supersymmetric Standard Model and first steps to go beyond these models. The other main focus is on the extraction of the characteristics and properties of the newly discovered p...
Heinemeyer, S; Passarino, G; Tanaka, R; Andersen, J R; Artoisenet, P; Bagnaschi, E A; Banfi, A; Becher, T; Bernlochner, F U; Bolognesi, S; Bolzoni, P; Boughezal, R; Buarque, D; Campbell, J; Caola, F; Carena, M; Cascioli, F; Chanon, N; Cheng, T; Choi, S Y; David, A; de Aquino, P; Degrassi, G; Del Re, D; Denner, A; van Deurzen, H; Diglio, S; Di Micco, B; Di Nardo, R; Dittmaier, S; Dührssen, M; Ellis, R K; Ferrera, G; Fidanza, N; Flechl, M; de Florian, D; Forte, S; Frederix, R; Frixione, S; Gangal, S; Gao, Y; Garzelli, M V; Gillberg, D; Govoni, P; Grazzini, M; Greiner, N; Griffiths, J; Gritsan, A V; Grojean, C; Hall, D C; Hays, C; Harlander, R; Hernandez-Pinto, R; Höche, S; Huston, J; Jubb, T; Kadastik, M; Kallweit, S; Kardos, A; Kashif, L; Kauer, N; Kim, H; Klees, R; Krämer, M; Krauss, F; Laureys, A; Laurila, S; Lehti, S; Li, Q; Liebler, S; Liu, X; Logan, E; Luisoni, G; Malberti, M; Maltoni, F; Mawatari, K; Maierhoefer, F; Mantler, H; Martin, S; Mastrolia, P; Mattelaer, O; Mazzitelli, J; Mellado, B; Melnikov, K; Meridiani, P; Miller, D J; Mirabella, E; Moch, S O; Monni, P; Moretti, N; Mück, A; Mühlleitner, M; Musella, P; Nason, P; Neu, C; Neubert, M; Oleari, C; Olsen, J; Ossola, G; Peraro, T; Peters, K; Petriello, F; Piacquadio, G; Potter, C T; Pozzorini, S; Prokofiev, K; Puljak, I; Rauch, M; Rebuzzi, D; Reina, L; Rietkerk, R; Rizzi, A; Rotstein-Habarnau, Y; Salam, G P; Sborlini, G; Schissler, F; Schönherr, M; Schulze, M; Schumacher, M; Siegert, F; Slavich, P; Smillie, J M; Stål, O; von Soden-Fraunhofen, J F; Spira, M; Stewart, I W; Tackmann, F J; Taylor, P T E; Tommasini, D; Thompson, J; Thorne, R S; Torrielli, P; Tramontano, F; Tran, N V; Trócsányi, Z; Ubiali, M; Vazquez Acosta, M; Vickey, T; Vicini, A; Waalewijn, W J; Wackeroth, D; Wagner, C; Walsh, J R; Wang, J; Weiglein, G; Whitbeck, A; Williams, C; Yu, J; Zanderighi, G; Zanetti, M; Zaro, M; Zerwas, P M; Zhang, C; Zirke, T J E; Zuberi, S
2013-01-01
This Report summarizes the results of the activities in 2012 and the first half of 2013 of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. This report follows the first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) and the second working group report Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002). After the discovery of a Higgs boson at the LHC in mid-2012 this report focuses on refined prediction of Standard Model (SM) Higgs phenomenology around the experimentally observed value of 125-126 GeV, refined predictions for heavy SM-like Higgs bosons as well as predictions in the Minimal Supersymmetric Standard Model and first steps to go beyond these models. The other main focus is on the extraction of the characteristics and properties of the newly discovered p...
Total and partial photoneutron cross sections for Pb isotopes
Kondo, T.; Utsunomiya, H.; Goriely, S.; Daoutidis, I.; Iwamoto, C.; Akimune, H.; Okamoto, A.; Yamagata, T.; Kamata, M.; Itoh, O.; Toyokawa, H.; Lui, Y.-W.; Harada, H.; Kitatani, F.; Hilaire, S.; Koning, A. J.
2012-07-01
Using quasimonochromatic laser-Compton scattering γ rays, total photoneutron cross sections were measured for 206,207,208Pb near neutron threshold with a high-efficiency 4π neutron detector. Partial E1 and M1 photoneutron cross sections along with total cross sections were determined for 207,208Pb at four energies near threshold by measuring anisotropies in photoneutron emission with linearly polarized γ rays. The E1 strength dominates over the M1 strength in the neutron channel where E1 photoneutron cross sections show extra strength of the pygmy dipole resonance in 207,208Pb near the neutron threshold corresponding to 0.32%-0.42% of the Thomas-Reiche-Kuhn sum rule. Several μN2 units of B(M1)↑ strength were observed in 207,208Pb just above neutron threshold, which correspond to an M1 cross section less than 10% of the total photoneutron cross section.
Partial Photoneutron Cross Sections for 207,208Pb
Kondo, T.; Utsunomiya, H.; Goriely, S.; Iwamoto, C.; Akimune, H.; Yamagata, T.; Toyokawa, H.; Harada, H.; Kitatani, F.; Lui, Y.-W.; Hilaire, S.; Koning, A. J.
2014-05-01
Using linearly-polarized laser-Compton scattering γ-rays, partial E1 and M1 photoneutron cross sections along with total cross sections were determined for 207,208Pb at four energies near neutron threshold by measuring anisotropies in photoneutron emission. Separately, total photoneutron cross sections were measured for 207,208Pb with a high-efficiency 4π neutron detector. The partial cross section measurement provides direct evidence for the presence of pygmy dipole resonance (PDR) in 207,208Pb in the vicinity of neutron threshold. The strength of PDR amounts to 0.32%-0.42% of the Thomas-Reiche-Kuhn sum rule. Several μN2 units of B(M1)↑ strength were observed in 207,208Pb just above neutron threshold, which correspond to M1 cross sections less than 10% of the total photoneutron cross sections.
Measurements of the total, elastic and inelastic pp cross section with ATLAS
Heinz, Christian; The ATLAS collaboration
2016-01-01
The total pp cross section is a fundamental property of the strong interaction which can not be calculated in perturbative QCD but only described based on phenomenological models. The ATLAS collaboration has recently measured the total inelastic protonproton cross section and the diffractive part of the inelastic cross section at 13 TeV in special data sets taken with low beam currents and using forward scintillators. A more precise measurement of the total pp cross section as well as elastic and inelastic contributions has been extracted from a measurement of the differential elastic cross section using the optical theorem. The ATLAS Collaboration has performed this measurement in elastic data collected with high beta* optics at 8 TeV centreofmass energy with the ALFA Roman Pot detector. From the extrapolation of the differential elastic cross section to t=0, using the optical theorem, the total cross section is extracted in a luminositydependent method with unprecedented precision. In addition the nuclear s...
Projectile and Lab Frame Differential Cross Sections for Electromagnetic Dissociation
Norbury, John W.; Adamczyk, Anne; Dick, Frank
2008-01-01
Differential cross sections for electromagnetic dissociation in nuclear collisions are calculated for the first time. In order to be useful for three - dimensional transport codes, these cross sections have been calculated in both the projectile and lab frames. The formulas for these cross sections are such that they can be immediately used in space radiation transport codes. Only a limited amount of data exists, but the comparison between theory and experiment is good.
A Theoretical Study of Photoabsorption Cross Sections of Na2+
Institute of Scientific and Technical Information of China (English)
ZHANG Wei-Hua; GAO Xiang; HAN Xiao-Ying; LI Jia-Ming
2007-01-01
@@ In the framework of quantum defect theory, we calculate photoabsorption cross sections of Na2+. Based on our calculations, there is an absorption window in the photoabsorption cross sections of Na2+, and more than one bump above the absorption window. The calculated photoabsorption cross sections provide an explanation for the abnormal bump in the experimental measurements of Hudson, which is a long-standing experimental puzzle.
Microscopic description of production cross sections including deexcitation effects
Sekizawa, Kazuyuki
2017-07-01
Background: At the forefront of the nuclear science, production of new neutron-rich isotopes is continuously pursued at accelerator laboratories all over the world. To explore the currently unknown territories in the nuclear chart far away from the stability, reliable theoretical predictions are inevitable. Purpose: To provide a reliable prediction of production cross sections taking into account secondary deexcitation processes, both particle evaporation and fission, a new method called TDHF+GEMINI is proposed, which combines the microscopic time-dependent Hartree-Fock (TDHF) theory with a sophisticated statistical compound-nucleus deexcitation model, GEMINI++. Methods: Low-energy heavy ion reactions are described based on three-dimensional Skyrme-TDHF calculations. Using the particle-number projection method, production probabilities, total angular momenta, and excitation energies of primary reaction products are extracted from the TDHF wave function after collision. Production cross sections for secondary reaction products are evaluated employing GEMINI++. Results are compared with available experimental data and widely used grazing calculations. Results: The method is applied to describe cross sections for multinucleon transfer processes in 40Ca+124Sn (Ec .m .≃128.54 MeV ), 48Ca+124Sn (Ec .m .≃125.44 MeV ), 40Ca+208Pb (Ec .m .≃208.84 MeV ), 58Ni+208Pb (Ec .m .≃256.79 MeV ), 64Ni+238U (Ec .m .≃307.35 MeV ), and 136Xe+198Pt (Ec .m .≃644.98 MeV ) reactions at energies close to the Coulomb barrier. It is shown that the inclusion of secondary deexcitation processes, which are dominated by neutron evaporation in the present systems, substantially improves agreement with the experimental data. The magnitude of the evaporation effects is very similar to the one observed in grazing calculations. TDHF+GEMINI provides better description of the absolute value of the cross sections for channels involving transfer of more than one proton, compared to the grazing
Positive Scattering Cross Sections using Constrained Least Squares
Energy Technology Data Exchange (ETDEWEB)
Dahl, J.A.; Ganapol, B.D.; Morel, J.E.
1999-09-27
A method which creates a positive Legendre expansion from truncated Legendre cross section libraries is presented. The cross section moments of order two and greater are modified by a constrained least squares algorithm, subject to the constraints that the zeroth and first moments remain constant, and that the standard discrete ordinate scattering matrix is positive. A method using the maximum entropy representation of the cross section which reduces the error of these modified moments is also presented. These methods are implemented in PARTISN, and numerical results from a transport calculation using highly anisotropic scattering cross sections with the exponential discontinuous spatial scheme is presented.
Systematics of fission cross sections at the intermediate energy region
Energy Technology Data Exchange (ETDEWEB)
Fukahori, Tokio; Chiba, Satoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1997-03-01
The systematics was obtained with fitting experimental data for proton induced fission cross sections of Ag, {sup 181}Ta, {sup 197}Au, {sup 206,207,208}Pb, {sup 209}Bi, {sup 232}Th, {sup 233,235,238}U, {sup 237}Np and {sup 239}Pu above 20 MeV. The low energy cross section of actinoid nuclei is omitted from systematics study, since the cross section has a complicated shape and strongly depends on characteristic of nucleus. The fission cross sections calculated by the systematics are in good agreement with experimental data. (author)
Capture cross sections from (p,d) reactions
Escher, J. E.; Burke, J. T.; Casperson, R. J.; Hughes, R. O.; Ota, S.; Scielzo, N. D.
2017-09-01
Cross sections for compound-nuclear reactions involving unstable targets are important for many applications, but can often not be measured directly. Several indirect methods have been proposed to determine neutron capture cross sections for unstable isotopes. We consider an approach that aims at constraining statistical calculations of capture cross sections with data obtained from light-ion transfer reactions such as (p,d). We discuss the theoretical descriptions that have to be developed in order to extract meaningful cross section constraints from such data and show some benchmark results.
Flow in Tubes of Non-Circular Cross-Sections
Quadir, Raushan Ara
In this thesis steady, laminar, viscous, incompressible flow in tubes of non-circular cross sections is investigated. The specific aims of the investigation are (a) to look at the problems of both developing flow and fully developed flow, (b) to consider non-circular cross sections in a more systematic manner than has been done in the past, and (c) to develop a relatively simple finite element technique for producing accurate numerical solutions of flow in tubes of fairly arbitrary cross sections. Fully developed flow in tubes is governed by a Poisson type equation for the mainstream velocity. Both analytical and numerical solutions are considered. The cross sections studied include elliptic and rectangular cross sections of different aspect ratios, some triangular cross sections, and a series of crescent-shaped cross sections. The physical characteristics of the flow are examined in a systematic manner in order to determine how these characteristics are affected by certain geometrical features of the cross section. Solutions fall into three basic categories depending on the shape of the cross section. In the first category, which includes circular and elliptic cross sections, solutions are possible in closed form. In the second, including rectangular and some triangular cross sections, solutions are in the form of infinite series. In the third, including cross sections of more complicated or irregular shapes, only numerical solutions are possible. Results of calculations of velocity profiles, flow rate, pumping power, and friction factor are presented in a way which can be useful for engineering applications. In numerical studies of both developing and fully developed flow finite element techniques are used. Results are obtained for tubes of rectangular and elliptic cross sections of different aspect ratios, for tubes of crescent -shaped cross sections and a tube whose cross section is an oval of Cassini. For fully developed flow, results are compared with the
Single boson production and differential cross section measurements in ATLAS
Debenedetti, Chiara; The ATLAS collaboration
2017-01-01
High-precision measurements of the Drell-Yan production allow to extract information on different aspects contributing to the process, such as parton distribution functions (PDFs), and to compare with the current precision reached theoretically on the calculations of the cross sections of such process. This document describes ATLAS measurements, performed at different centre of mass energies of vector boson (W and Z) cross sections and cross-section ratios, and ratios of Z-boson and top-quark pair production cross sections, obtaining important information on the proton PDFs.
Phenomenological dirac optical potential for neutron cross sections
Energy Technology Data Exchange (ETDEWEB)
Maruyama, Shin-ichi; Kitsuki, Hirohiko; Shigyo, Nobuhiro; Ishibashi, Kenji [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering
1997-03-01
Because of limitation on neutron-incident data, it is difficult to obtain global optical model potential for neutrons. In contrast, there are some global optical model potentials for proton in detail. It is interesting to convert the proton-incident global optical potentials into neutron-incident ones. In this study we introduce (N-Z)/A dependent symmetry potential terms into the global proton-incident optical potentials, and then obtain neutron-incident ones. The neutron potentials reproduce total cross sections in an acceptable degree. However, a comparison with potentials proposed by other authors brings about a confused situation in the sign of the symmetry terms. (author)
Proton radiography, nuclear cross sections and multiple Coulomb scattering
Energy Technology Data Exchange (ETDEWEB)
Sjue, Sky K. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-11-04
The principles behind proton radiography including multiple Coulomb scattering are discussed for a purely imaginary square well nucleus in the eikonal approximation. It is found that a very crude model can reproduce the angular dependence of the cross sections measured at 24 GeV/c. The largest differences are ~3% for the 4.56 mrad data, and ~4% for the 6.68 mrad data. The prospect of understanding how to model deterministically high-energy proton radiography over a very large range of energies is promising, but it should be tested more thoroughly.
Proton-deuteron radiative capture cross sections at intermediate energies
Mehmandoost-Khajeh-Dad, A A; Amir-Ahmadi, H R; Bacelar, J C S; Berg, A M van den; Castelijns, R; van Garderen, E D; Kalantar-Nayestanaki, N; Kiš, M; Löhner, H; Messchendorp, J G; Wörtche, H J
2011-01-01
Differential cross sections of the reaction $p(d,^3{\\rm He})\\gamma$ have been measured at deuteron laboratory energies of 110, 133 and 180 MeV. The data were obtained with a coincidence setup measuring both the outgoing $^3$He and the photon. The data are compared with modern calculations including all possible meson-exchange currents and two- and three- nucleon forces in the potential. The data clearly show a preference for one of the models, although the shape of the angular distribution cannot be reproduced by any of the presented models.
Neutrino-Nucleus Cross Sections for Oscillation Experiments
Katori, Teppei
2016-01-01
Neutrino oscillations physics is entered in the precision era. In this context accelerator-based neutrino experiments need a reduction of systematic errors to the level of a few percent. Today one of the most important sources of systematic errors are neutrino-nucleus cross sections which in the hundreds-MeV to few-GeV energy region are known with a precision not exceeding 20%. In this article we review the present experimental and theoretical knowledge of the neutrino-nucleus interaction physics. After introducing neutrino oscillation physics and accelerator-based neutrino experiments, we overview general aspects of the neutrino-nucleus cross sections, both theoretical and experimental views. Then we focus on these quantities in different reaction channels. We start with the quasielastic and quasielastic-like cross section, putting a special emphasis on multinucleon emission channel which attracted a lot of attention in the last few years. We review the main aspects of the different microscopic models for th...
Measurements of four fermion cross-sections at LEP
Kopal, Miroslav
2002-01-01
The production of four fermions in e+e− collisions at LEP allows the verification of the Standard Model of the Electroweak Interactions in the Charged and Neutral Current Sectors. Among the four-fermion final states, the highest purity and the clearest four-fermion events are characterized by the presence of leptons in the final state. The identification of such final states in the full data sample collected by the L3 experiment at LEP in the years from 1997 through 2000 is described. The total amount of data analyzed in this thesis corresponds to the total integrated luminosity 675.5 pb−1. ^ This thesis presents the results of the selection of the Z boson pair production together with the measurement of the cross-section for leptonic four-fermion final states, and the first measurement of cross-sections in the four-lepton and two-lepton and missing energy channels of the Zg* production with the L3 detector. The cross-section average over the whole data sample was found to be: s&parl0;e+e-→Zg *→l+...
Detecting Neutrinos from AGN New Fluxes and Cross Sections
Hill, G C
1996-01-01
New information on the structure of the nucleon from the HERA ep collider leads to higher neutrino cross sections for the processes nu_mu + N --> mu + X needed to calculate the expected rates of astrophysical neutrino induced muons in large detectors either under construction, or in the design stage. These higher cross sections lead to higher muon rates for arrival angles where neutrino attenuation in the earth is less important. On the other hand, new estimates of AGN neutrino fluxes suggest that the expected muon rates in these detectors may be much lower than previously calculated. I use the new cross sections to calculate the expected muon rates and angular distributions in large detectors for a variety of AGN models and compare these rates with the atmospheric neutrino backrounds (from both conventional decay channels and the "prompt" charmed meson decay channels). If the lowest flux estimates are correct, there may be diffculties in determining the origin of a small excess of muons, due to the large unc...
Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables
Dittmaier, S; Passarino, G; Tanaka, R; Baglio, J; Bolzoni, P; Boughezal, R; Brein, O; Collins-Tooth, C; Dawson, S; Dean, S; Denner, A; Farrington, S; Felcini, M; Flechl, M; de Florian, D; Forte, S; Grazzini, M; Hackstein, C; Hahn, T; Harlander, R; Hartonen, T; Heinemeyer, S; Huston, J; Kalinowski, A; Krämer, M; Krauss, F; Lee, J S; Lehti, S; Maltoni, F; Mazumdar, K; Moch, S -O; Mück, A; Mühlleitner, M; Nason, P; Neu, C; Oleari, C; Olsen, J; Palmer, S; Petriello, F; Piacquadio, G; Pilaftsis, A; Potter, C T; Puljak, I; Qian, J; Rebuzzi, D; Reina, L; Rzehak, H; Schumacher, M; Slavich, P; Spira, M; Stöckli, F; Thorne, R S; Acosta, M Vazquez; Vickey, T; Vicini, A; Wackeroth, D; Warsinsky, M; Weber, M; Weiglein, G; Weydert, C; Yu, J; Zaro, M; Zirke, T
2011-01-01
This Report summarizes the results of the first 10 months' activities of the LHC Higgs Cross Sections Working Group. The main goal of the working group was to present the status-of-art on Higgs Physics at the LHC integrating all new results that have appeared in the last few years. The Report is more than a mere collection of the proceedings of the general meetings. The subgroups have been working in different directions. An attempt has been made to present the first Report from these subgroups in a complete and homogeneous form. The subgroups' contributions correspondingly comprise the main parts of the Report. A significant amount of work has been performed in providing higher-order corrections to the Higgs-boson cross sections and pinning down the theoretical uncertainty of the Standard Model predictions. This Report comprises explicit numerical results on total cross sections, leaving the issues of event selection cuts and differential distributions to future publications. The subjects for further study a...
Fully hadronic ttbar cross section measurement with ATLAS detector
Bertella, Claudia
2011-01-01
The top quark pair production cross section in the fully hadronic final state is characterized by a six jet topology, two of which could be identified as originating from a b-quark using ATLAS b-tagging algorithms. Compared to other decay channels, this final state presents an advantageous larger branching ratio; on the other hand it suffers from a very large QCD multi-jet background, generally difficult to estimate from Monte Carlo simulation and therefore evaluated using data-driven techniques. The analysis is performed using 36pb-1 of pp collisions produced at the LHC with a center-of-mass energy of 7 TeV. The observed upper limit is set at 261 pb at 95% confidence level, where the expected Standard Model cross-section for the ttbar process is 165+11-16 pb. In the future, when the LHC luminosity increases, it is essential, to efficiently trigger on these fully hadronic ttbar events, to use dedicated triggers. An overview of the analysis for ttbar production cross section measurement in the fully hadronic f...
Measuring the FSR-inclusive $\\pi^{+}\\pi^{-}$ cross section
Gluza, J; Jadach, Stanislaw; Jegerlehner, F
2003-01-01
Final state radiation (FSR) in pion--pair production cannot be calculated reliably because of the composite structure of the pions. However, FSR corrections have to be taken into account for a precise evaluation of the hadronic contribution to g-2 of the muon. The role of FSR in both energy scan and radiative return experiments is discussed. It is shown how FSR influences the pion form factor extraction from experimental data and, as a consequence, the evaluation of a_mu^had. In fact the O(alpha) FSR corrections should be included to reach the precision we are aiming at. We argue that for an extraction of the desired FSR--inclusive cross section sigma^(gamma)_had a photon--inclusive scan measurement of the ``e+e- to pi+pi- + photons'' cross section is needed. For exclusive scan and radiative return measurements in contrast we have to rely on ad hoc FSR models if we want to obtain either sigma^(gamma)_had or the FSR--exclusive cross section sigma^(0)_had. We thus advocate to consider seriously precise photon--...
Extension of the Bgl Broad Group Cross Section Library
Kirilova, Desislava; Belousov, Sergey; Ilieva, Krassimira
2009-08-01
The broad group cross-section libraries BUGLE and BGL are applied for reactor shielding calculation using the DOORS package based on discrete ordinates method and multigroup approximation of the neutron cross-sections. BUGLE and BGL libraries are problem oriented for PWR or VVER type of reactors respectively. They had been generated by collapsing the problem independent fine group library VITAMIN-B6 applying PWR and VVER one-dimensional radial model of the reactor middle plane using the SCALE software package. The surveillance assemblies (SA) of VVER-1000/320 are located on the baffle above the reactor core upper edge in a region where geometry and materials differ from those of the middle plane and the neutron field gradient is very high which would result in a different neutron spectrum. That is why the application of the fore-mentioned libraries for the neutron fluence calculation in the region of SA could lead to an additional inaccuracy. This was the main reason to study the necessity for an extension of the BGL library with cross-sections appropriate for the SA region. Comparative analysis of the neutron spectra of the SA region calculated by the VITAMIN-B6 and BGL libraries using the two-dimensional code DORT have been done with purpose to evaluate the BGL applicability for SA calculation.
Measuring Neutron-Induced Reaction Cross Sections without Neutrons
Bernstein, L. A.; Schiller, A.; Cooper, J. R.; Hoffman, R. D.; McMahan, M. A.; Fallon, P.; Macchiavelli, A. O.; Mitchell, G.; Tavukcu, E.; Guttormsen, M.
2003-04-01
Neutron-induced reactions on radioactive nuclei play a significant role in nuclear astrophysics and many other applied nuclear physics topics. However, the majority of these cross sections are impossible to measure due to the high-background of the targets and the low-intensity of neutron beams. We have explored the possibility of using charged-particle transfer reactions to form the same "pre-compound" nucleus as one formed in a neutron-induced reaction in order to measure the relative decay probabilities of the nucleus as a function of energy. Multiplying these decay probabilities by the neutron absorption cross section will then produce the equivalent neutron-induced reaction cross section. In this presentation I will explore the validity of this "surrogate reaction" technique by comparing results from the recent 157Gd(3He,axng)156-xGd experiment using STARS (Silicon Telescope Array for Reaction Studies) at GAMMASPHERE with reaction model calculations for the 155Gd(n,xng)156-xGd. This work was funded by the US Department of Energy under contracts number W-7405-ENG-48 (LLNL), AC03-76SF00098 (LBNL) and the Norwegian Research Council (Oslo).
Determination of Optimum Cross-section for Oran Highway Revetment
Velioglu, Deniz; Sogut, Erdinc; Guler, Isikhan
2017-04-01
Revetments are shore parallel, sloping coastal structures which are built to provide protection from the negative effects of the sea. The revetment mentioned in this study is located in the City of Oran, Algeria and is currently under construction. This study investigates the determination of the optimum revetment cross section for Oran highway, considering both the hydraulic stability of the revetment and economy. The existence of cliffs in the region and the settlement of the City of Oran created a necessity to re-align Oran highway; therefore, it was shifted towards the Gulf of Oran. Approximately 1 km of the highway is to be constructed on the Mediterranean Sea due to the new alignment. In order to protect the sea side of the road from the adverse effects of the sea, a revetment was designed. The proposed cross section had an armour layer composed of 23 tons of antifer units and regular placement of armour units was recommended. In order to check the hydraulic stability of the proposed section, physical model tests were performed in the laboratory of LEM (Laboratoire d'Etudes Maritimes) in Algeria, using the pre-determined design wave conditions. The physical model tests revealed that the trunk of the revetment was totaly damaged. Accordingly, the proposed section was found insufficient and certain modifications were required. The first modification was made in the arrangement of armour units, changing them from regular to irregular. After testing the new cross section, it was observed that the revetment was vulnerable to breaking wave attack due to the toe geometry and thus the toe of the revetment had to be re-shaped. Therefore, the second option was to reduce the toe elevation. It was observed that even though the revetment trunk was safe, the damage in the toe was not in acceptable limits. The new cross section was found insufficient and as the final option, the weight of the antifer units used in the armour layer was increased, the toe length of the
Institute of Scientific and Technical Information of China (English)
Yun-Wu Zhao; Jing-Ya Wu; Heng Wang; Nian-Nian Li; Cheng Bian; Shu-Man Xu; Peng Li
2015-01-01
Background:The self-consciousness and practicality of preferentially prescribed essential medicines (EMs) are not high enough in county hospitals.The purposes of this study were to use the information-motivation-behavioral skills (IMB) model to identify the predictors of essential medicines prescribing behavior (EMPB) among doctors and to examine the association between demographic variables,IMB,and EMPB.Methods:A cross-sectional study was carried out to assess predictive relationships among demographic variables and IMB model variables using an anonymous questionnaire administered in nine county hospitals of Anhui province.A structural equation model was constructed for the IMB model to test the instruments using analysis of moment structures 17.0.Results:A total of 732 participants completed the survey.The average age of the participants was 37.7 ± 8.9 years old (range:22-67 years old).The correct rate of information was 90.64％.The average scores of the motivation and behavioral skills were 45.46 ± 7.34 (hundred mark system:75.77) and 19.92 ± 3.44 (hundred mark system:79.68),respectively.Approximately half(50.8％) of respondents reported that the proportion of EM prescription was below 60％.The final revised model indicated a good fit to the data (x2/df=4.146,goodness of fit index =0.948,comparative fit index =0.938,root mean square error of approximation =0.066).More work experience (β =0.153,P ＜ 0.001) and behavioral skills (β =0.449,P ＜ 0.001) predicted more EMPB.Higher income predicted less information (β =-0.197,P ＜ 0.001) and motivation (β =-0.204,P ＜ 0.001).Behavioral skills were positively predicted by information (β =0.135,P ＜ 0.001) and motivation (β =0.742,P ＜ 0.001).Conclusion:The present study predicted some factors of EMPB,and specified the relationships among the model variables.The utilization rate of EM was not high enough.Motivation and behavior skills were crucial factors affecting EMPB.The influence of demographic
Ni elemental neutron induced reaction cross-section evaluation
Energy Technology Data Exchange (ETDEWEB)
Divadeenam, M.
1979-03-01
A completely new evaluation of the nickel neutron induced reaction cross sections was undertaken as a part of the ENDF/B-V effort. (n,xy) reactions and capture reaction time from threshold to 20 MeV were considered for /sup 58/ /sup 60/ /sup 61/ /sup 62/ /sup 64/Ni isotopes to construct the corresponding reaction cross section for natural nickel. Both experimental and theoretical calculated results were used in evaluating different partial cross sections. Precompound effects were included in calculating (n,xy) reaction cross sections. Experimentally measured total section data extending from 0.7 MeV to 20 MeV were used to generate smooth cross section. Below 0.7 to MeV elastic and capture cross sections are represented by resonance parameters. Inelastic angular distributions to the discrete isotopic levels and elemental elastic angular distributions are included in the evaluated data file. Gamma production cross sections and energy distribution due to capture and the (n,xy) reactions were evaluated from experimental data. Finally, error files are constructed for all partial cross sections.
Cross sectional moments and portfolio returns: Evidence for select emerging markets
Directory of Open Access Journals (Sweden)
Sanjay Sehgal
2016-09-01
Full Text Available Research does not indicate a consensus on the relationship between idiosyncratic volatility and asset returns. Moreover, the role of cross sectional higher order moments in predicting market returns is relatively unexplored. We show that the cross sectional volatility measure suggested by Garcia et al. is highly correlated with alternative measures of idiosyncratic volatility constructed as variance of errors from the capital asset pricing model and the Fama French model. We find that cross sectional moments help in predicting aggregate market returns in some sample countries and also provide information for portfolio formation, which is more consistent for portfolios sorted on sensitivity to cross sectional skewness.
Directory of Open Access Journals (Sweden)
Jarman Ian
2010-04-01
Full Text Available Abstract Background Management of nightlife in UK cities focuses on creating safe places for individuals to drink. Little is known about intoxication levels as measuring total alcohol consumption on nights out is complicated by early evening interviews missing subsequent consumption and later interviews risking individuals being too drunk to recall consumption or participate at all. Here we assess mixed survey and modelling techniques as a methodological approach to examining these issues. Methods Interviews with a cross sectional sample of nightlife patrons (n = 214 recruited at different locations in three cities established alcohol consumption patterns up to the point of interview, self-assessed drunkenness and intended drinking patterns throughout the remaining night out. Researchers observed individuals' behaviours to independently assess drunkenness. Breath alcohol tests and general linear modelling were used to model blood alcohol levels at participants' expected time of leaving nightlife settings. Results At interview 49.53% of individuals regarded themselves as drunk and 79.43% intended to consume more alcohol before returning home, with around one in ten individuals (15.38% males; 4.35% females intending to consume >40 units (equal to 400 mls of pure alcohol. Self-assessed drunkenness, researcher observed measures of sobriety and blood alcohol levels all correlated well. Modelled estimates for blood alcohol at time of going home suggested that 71.68% of males would be over 0.15%BAC (gms alcohol/100 mls blood. Higher blood alcohol levels were related to drinking later into the night. Conclusions UK nightlife has used substantive health and judicial resources with the aim of creating safer and later drinking environments. Survey and modelling techniques together can help characterise the condition of drinkers when using and leaving these settings. Here such methods identified patrons as routinely getting drunk, with risks of drunkenness
New physics, the cosmic ray spectrum knee, and $pp$ cross section measurements
Dixit, Aparna; McKay, Douglas W; Mukherjee, Parama
2009-01-01
We model new physics modifications to the total proton-proton cross section with an incoherent term that allows for missing energy above the scale of new physics. We explore the possibility that the new physics interaction alone can provide an explanation for the knee just above $10^6$ GeV in the cosmic ray spectrum. We add the constraint that the new physics must also be consistent with published $pp$ cross section measurements an order of magnitude and more above the knee. Allowing for the necessary rescaling of the cross section data in the light of the new physics, we find parameter ranges in several generic models that readily give good quality fits to recently published Tibet III spectrum analysis and to the rescaled direct cross section measurements. The rise in cross section required at energies above the knee is radical. Even before reaching design energy, the Large Hadron Collider can test this picture with total cross section measurements.
Sectioning Clay Models Makes Anatomy & Development Tangible
Howell, Carina Endres; Howell, James Endres
2010-01-01
Clay models have proved to be useful teaching aids for many topics in biology that depend on three-dimensional reasoning. Students studying embryonic development struggle to mentally reconstruct the three-dimensional structure of embryos and larvae by observing prepared slides of cross-sectional slices. Students who build clay models of embryos…
Re/Os cosmochronometer: measurement of neutron cross sections
Energy Technology Data Exchange (ETDEWEB)
Mosconi, M.
2007-12-21
This experimental work is devoted to the improved assessment of the Re/Os cosmochronometer. The dating technique is based on the decay of {sup 187}Re (t{sub 1/2}=41.2 Gyr) into {sup 187}Os and determines the age of the universe by the time of onset of nucleosynthesis. The nucleosynthesis mechanisms, which are responsible for the {sup 187}Re/{sup 187}Os pair, provide the possibility to identify the radiogenic fraction of {sup 187}Os exclusively by nuclear physics considerations. Apart from its radiogenic component, {sup 187}Os can be synthesized otherwise only by the s process, which means that this missing fraction can be reliably determined and subtracted by proper s-process modeling. On the other hand, {sup 187}Re is almost completely produced by the r process. The only information needed for the interpretation as a cosmic clock is the production rate of {sup 187}Re as a function of time. The accuracy of the s-process calculations that are needed to determine the nucleosynthetic abundance of {sup 187}Os depends on the quality of the neutron capture cross sections averaged over the thermal neutron spectrum at the s-process sites. Laboratory measurements of these cross sections have to be corrected for the effect of nuclear levels, which can be significantly populated at the high stellar temperatures during the s process. The neutron capture cross sections of {sup 186}Os, {sup 187}Os and {sup 188}Os have been measured at the CERN n TOF facility in the range between 0.7 eV and 1 MeV. From these data, Maxwellian averaged cross sections have been determined for thermal energies from 5 to 100 keV with an accuracy around 4%, 3%, and 5% for {sup 186}Os, {sup 187}Os, and {sup 188}Os, respectively. Since, the first excited state in {sup 187}Os occurs at 9.75 keV, the cross section of this isotope requires a substantial correction for thermal population of low lying nuclear levels. This effect has been evaluated on the basis of resonance data derived in the (n, {gamma
Re/Os cosmochronometer: measurement of neutron cross sections
Energy Technology Data Exchange (ETDEWEB)
Mosconi, M.
2007-12-21
This experimental work is devoted to the improved assessment of the Re/Os cosmochronometer. The dating technique is based on the decay of {sup 187}Re (t{sub 1/2}=41.2 Gyr) into {sup 187}Os and determines the age of the universe by the time of onset of nucleosynthesis. The nucleosynthesis mechanisms, which are responsible for the {sup 187}Re/{sup 187}Os pair, provide the possibility to identify the radiogenic fraction of {sup 187}Os exclusively by nuclear physics considerations. Apart from its radiogenic component, {sup 187}Os can be synthesized otherwise only by the s process, which means that this missing fraction can be reliably determined and subtracted by proper s-process modeling. On the other hand, {sup 187}Re is almost completely produced by the r process. The only information needed for the interpretation as a cosmic clock is the production rate of {sup 187}Re as a function of time. The accuracy of the s-process calculations that are needed to determine the nucleosynthetic abundance of {sup 187}Os depends on the quality of the neutron capture cross sections averaged over the thermal neutron spectrum at the s-process sites. Laboratory measurements of these cross sections have to be corrected for the effect of nuclear levels, which can be significantly populated at the high stellar temperatures during the s process. The neutron capture cross sections of {sup 186}Os, {sup 187}Os and {sup 188}Os have been measured at the CERN n TOF facility in the range between 0.7 eV and 1 MeV. From these data, Maxwellian averaged cross sections have been determined for thermal energies from 5 to 100 keV with an accuracy around 4%, 3%, and 5% for {sup 186}Os, {sup 187}Os, and {sup 188}Os, respectively. Since, the first excited state in {sup 187}Os occurs at 9.75 keV, the cross section of this isotope requires a substantial correction for thermal population of low lying nuclear levels. This effect has been evaluated on the basis of resonance data derived in the (n, {gamma
From ZZ to ZH : How Low Can These Cross Sections Go or Everybody, Let's Cross Section Limbo!
Energy Technology Data Exchange (ETDEWEB)
Strauss, Emanuel Alexandre [Stony Brook Univ., NY (United States)
2009-08-01
We report on two searches performed at the D0 detector at the Fermi National Laboratory. The first is a search for Z di-boson production with a theoretical cross section of 1.4 pb. The search was performed on 2.6 fb^{-1} of data and contributed to the first observation of ZZ production at a hadron collider. The second is a search for a low mass Standard Model Higgs in 4.2 fb^{-1} of data. The Higgs boson is produced in association with a Z boson where the Higgs decays hadronically and the Z decays to two leptons. The ZZ search was performed in both the di-electron and di-muon channels. For the ZH search, we will focus on the muonic decays where we expanded the traditional coverage by considering events in which one of the two muons fails the selection requirement, and is instead reconstructed as an isolated track. We consider Higgs masses between 100 and 150 GeV, with theoretical cross sections ranging from 0.17 to 0.042 pb, and set upper limits on the ZH production cross-section at 95% confidence level.
Nuclear characteristics of Pu fueled LWR and cross section sensitivities
Energy Technology Data Exchange (ETDEWEB)
Takeda, Toshikazu [Osaka Univ., Suita (Japan). Faculty of Engineering
1998-03-01
The present status of Pu utilization to thermal reactors in Japan, nuclear characteristics and topics and cross section sensitivities for analysis of Pu fueled thermal reactors are described. As topics we will discuss the spatial self-shielding effect on the Doppler reactivity effect and the cross section sensitivities with the JENDL-3.1 and 3.2 libraries. (author)
On the scattering cross section of passive linear arrays
DEFF Research Database (Denmark)
Solymar, L.
1973-01-01
A general formula is derived for the scattering cross section of a passiven-element linear array consisting of isotropic radiators. When all the reactances are tuned out and scattering in the mirror direction is investigated, it is found thatA_{sr}, the relative scattering cross section is equal ...
Determination of Electron Collision Cross Sections Set for Tetramethysilane
Institute of Scientific and Technical Information of China (English)
Marie-Claude BORDAGE
2007-01-01
A swarm analysis technique based on the solution of the Boltzmann equation is used to derive low energy electron collision cross sections for tetramethylsilane (TMS).The calculated swarm parameters with this first available cross sections set is consistent with measured values of the swarm parameters.Calculations of transport parameters in mixtures of TMS with argon are also presented.
Parametric equations for calculation of macroscopic cross sections
Energy Technology Data Exchange (ETDEWEB)
Botelho, Mario Hugo; Carvalho, Fernando, E-mail: mariobotelho@poli.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear
2015-07-01
Neutronic calculations of the core of a nuclear reactor is one thing necessary and important for the design and management of a nuclear reactor in order to prevent accidents and control the reactor efficiently as possible. To perform these calculations a library of nuclear data, including cross sections is required. Currently, to obtain a cross section computer codes are used, which require a large amount of processing time and computer memory. This paper proposes the calculation of macroscopic cross section through the development of parametric equations. The paper illustrates the proposal for the case of macroscopic cross sections of absorption (Σa), which was chosen due to its greater complexity among other cross sections. Parametric equations created enable, quick and dynamic way, the determination of absorption cross sections, enabling the use of them in calculations of reactors. The results show efficient when compared with the absorption cross sections obtained by the ALPHA 8.8.1 code. The differences between the cross sections are less than 2% for group 2 and less than 0.60% for group 1. (author)
Cross sections for electron collisions with nitric oxide
Itikawa, Yukikazu
2016-09-01
Cross section data are reviewed for electron collisions with nitric oxide. Collision processes considered are total scattering, elastic scattering, momentum transfer, excitations of rotational, vibrational, and electronic states, ionization, and dissociative electron attachment. After a survey of the literature (up to the end of 2015), recommended values of the cross section are determined, as far as possible.
Energy Technology Data Exchange (ETDEWEB)
Lucotte, A. [Grenoble-1 Univ., 74 - Annecy (France). Lab. de Physique des Particules Elementaires; Universite Claude Bernard, 69 - Lyon (France)
1996-05-14
This work is devoted to the precision tests of the electro-week sector of the standard model via the determination of the Z-lineshape parameters M{sub Z}, {gamma}{sub Z}, {sigma}{sub had}{sup 0} and R{sub had} extracted from the fermionic cross-sections measured on 89 to 94 data in Aleph. The first section reminds the formalism and the observables used to describe the Z-resonance physics. In a second step, the LEP collider is presented with the procedures used to determine the beam energy, this parameter being the main source of uncertainty in M{sub Z} and {gamma}{sub Z} determination. In the following part, the Aleph experimental context is described, together with the measurement of the luminosity from Bhabha counting. Then the hadronic cross section measurements are presented, emphasizing on the improvement performed on the systematic bias evaluation to the hadrons selection. This leads to a precision at the per mille level in cross-sections. Leptonic cross-sections measured in Aleph are also reported. The Z-resonance parameters are then derived. A great agreement is observed with the prediction of the standard model of the EW interactions. The interpretation of such measurements within this model leads to the determination of the number of light neutrinos species and to the constraints on the top quark mass, compatible with direct measurements from Fermilab. (author)
Hirose, Atsumi; Borchert, Matthias; Cox, Jonathan; Alkozai, Ahmad Shah; Filippi, Veronique
2015-02-05
Women's delays in reaching emergency obstetric care (EmOC) facilities contribute to high maternal and perinatal mortality and morbidity in low-income countries, yet few studies have quantified travel times to EmOC and examined delays systematically. We defined a delay as the difference between a woman's travel time to EmOC and the optimal travel time under the best case scenario. The objectives were to model travel times to EmOC and identify factors explaining delays. i.e., the difference between empirical and modelled travel times. A cost-distance approach in a raster-based geographic information system (GIS) was used for modelling travel times. Empirical data were obtained during a cross-sectional survey among women admitted in a life-threatening condition to the maternity ward of Herat Regional Hospital in Afghanistan from 2007 to 2008. Multivariable linear regression was used to identify the determinants of the log of delay. Amongst 402 women, 82 (20%) had no delay. The median modelled travel time, reported travel time, and delay were 1.0 hour [Q1-Q3: 0.6, 2.2], 3.6 hours [Q1-Q3: 1.0, 12.0], and 2.0 hours [Q1-Q3: 0.1, 9.2], respectively. The adjusted ratio (AR) of a delay of the "one-referral" group to the "self-referral" group was 4.9 [95% confidence interval (CI): 3.8-6.3]. Difficulties obtaining transportation explained some delay [AR 2.1 compared to "no difficulty"; 95% CI: 1.5-3.1]. A husband's very large social network (> = 5 people) doubled a delay [95% CI: 1.1-3.7] compared to a moderate (3-4 people) network. Women with severe infections had a delay 2.6 times longer than those with postpartum haemorrhage (PPH) [95% CI: 1.4-4.9]. Delays were mostly explained by the number of health facilities visited. A husband's large social network contributed to a delay. A complication with dramatic symptoms (e.g. PPH) shortened a delay while complications with less-alarming symptoms (e.g. severe infection) prolonged it. In-depth investigations are needed to
Energy Technology Data Exchange (ETDEWEB)
Baimbetov, F B; Kudyshev, Z A [Department of Physics, Al-Farabi Kazakh National University, 050012 Almaty (Kazakhstan)], E-mail: Fazylhan.Baimbetov@kaznu.kz, E-mail: Z.Kudyshev@mail.ru
2009-05-29
In the present work an electron impact ionization cross section is considered. The electron impact ionization cross section is calculated with the help of a variable phase approach to potential scattering. The Calogero equation is numerically solved, based on a pseudopotential model of interaction between partially ionized plasma particles, which accounts for correlation effects. As a result, scattering phase shifts are obtained. On the basis of the scattering phase shifts, the ionization cross section is calculated.
New neutrino-nucleus reaction cross sections at solar, reactor and supernova neutrino energies
Directory of Open Access Journals (Sweden)
Suzuki Toshio
2014-03-01
Full Text Available Remarkable improvements in the evaluation of neutrino-nucleus reaction cross sections are obtained based on new shell-model Hamiltonians with proper tensor components. New ν-induced reaction cross sections on 12C, 13C, 56Fe, 56Ni and 40Ar are presented, and predictions for nucleosynthesis in supernova explosions, ν-oscillation effects and low-energy reactor and solar neutrino detection are discussed based on these new cross sections.
On river cross-sectional change in the Niger Delta
Abam, T. K. S.; Omuso, W. O.
2000-08-01
A network of dominantly distributary river systems dissects the superficial deposits of the Niger Delta comprising alluvial sediments. Changes in river cross-sections are instigated mainly by bank failures, fluctuations in discharge, and bed degradation by fluvial processes. The relative importance of factors causing river cross-sectional change was ranked, based on a deterministic sensitivity technique involving partial differentiation of soil properties, flow characteristics, and geometrical parameters of the river channels. Analysis suggests that steep bank inclination and high flow velocity/discharge are the major causes of cross-sectional change, while interlocking of soil grains is the major erosion-restraining factor. Sensitivity coefficients were used further to generate susceptibility indices, indicating the vulnerability of channel cross-sections to change. Based on this, the risks of channel cross-sectional change were compared at different sites.
Temperature-dependent high resolution absorption cross sections of propane
Beale, Christopher A.; Hargreaves, Robert J.; Bernath, Peter F.
2016-10-01
High resolution (0.005 cm-1) absorption cross sections have been measured for pure propane (C3H8). These cross sections cover the 2550-3500 cm-1 region at five temperatures (from 296 to 700 K) and were measured using a Fourier transform spectrometer and a quartz cell heated by a tube furnace. Calibrations were made by comparison to the integrated cross sections of propane from the Pacific Northwest National Laboratory. These are the first high resolution absorption cross sections of propane for the 3 μm region at elevated temperatures. The cross sections provided may be used to monitor propane in combustion environments and in astronomical sources such as the auroral regions of Jupiter, brown dwarfs and exoplanets.
Relations between photoionization cross sections and photon radius
Liu, Shan-Liang
2016-01-01
The relations between photoionization cross sections and photon radius are obtained on basis of quantum mechanics and the particle-like properties of a photon. The photoionization cross sections of H atom and H-like ions, He atom and He like ions, alkali metal atoms, and Rydberg atoms are calculated using the relations. The calculation results are found to be good agreement with the known experimental data. The results show that the photoionization cross section is always smaller than the cross section of the photon to ionize the atom or ion and can be expressed as the product of the cross section of the photon and the probability that electron meets with the photon. These provide the intuitive understanding for the photoionization phenomena and open a new avenue of research on interaction between a photon and an atom or ion.
Cross sections for electron collisions with dimethyl ether
Sugohara, RT; Homem, MGP; Iga, I; de Souza, GLC; MACHADO, LE; Ferraz, JR; dos Santos, AS; Brescansin, LM; Lucchese, RR; Lee, MT
2013-01-01
We report a joint theoretical-experimental investigation of electron collision with dimethyl ether (DME) in the low- and intermediate-energy ranges. Experimental absolute differential, integral, and momentum-transfer cross sections for elastic e(-)-DME scattering are reported in the 100-1000 eV energy range. Our measurements were performed using a crossed electron-beam-molecular-beam geometry. The angular distribution of the scattered electrons was converted to absolute cross section using th...
Leineweber, C; Chungkham, H S; Westerlund, H; Tishelman, C; Lindqvist, R
2014-05-01
The present shortage of registered nurses (RNs) in many European countries is expected to continue and worsen, which poses a substantial threat to the maintenance of healthcare in this region. Work-family conflict is a known risk factor for turnover and sickness absence. This paper empirically examines whether the nurse practice environment is associated with experienced work-family conflict. A multilevel model was fit with the individual RN at the 1st, and the hospital department at the 2nd level using cross-sectional RN survey data from the Swedish part of RN4CAST, an EU 7th framework project. The data analyzed here is based on a national sample of 8356 female and 592 male RNs from 369 hospital departments. We found that 6% of the variability in work-family conflict experienced by RNs was at the department level. Organizational level factors significantly accounted for most of the variability at this level with two of the work practice environment factors examined, staffing adequacy and nurse involvement in hospital affairs, significantly related to work-family conflict. Due to the design of the study, factors on ward and work group levels could not be analyzed, but are likely to account for additional variance which in the present analysis appears to be on the individual level, with private life factors likely explaining another major part. These results suggest that higher level organizational factors in health care have a significant impact on the risk of work-family conflict among RNs through their impact on the nurse practice environment. Lower level organizational factors should be investigated in future studies using hierarchical multilevel sampling. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.
Shoham, David A; Harris, Jenine K; Mundt, Marlon; McGaghie, William
2016-09-01
Healthcare teams consist of individuals communicating with one another during patient care delivery. Coordination of multiple specialties is critical for patients with complex health conditions, and requires interprofessional and intraprofessional communication. We examined a communication network of 71 health professionals in four professional roles: physician, nurse, health management, and support personnel (dietitian, pharmacist, or social worker), or other health professionals (including physical, respiratory, and occupational therapists, and medical students) working in a burn unit. Data for this cross-sectional study were collected by surveying members of a healthcare team. Ties were defined by asking team members whom they discussed patient care matters with on the shift. We built an exponential random graph model to determine: (1) does professional role influence the likelihood of a tie; (2) are ties more likely between team members from different professions compared to between team members from the same profession; and (3) which professions are more likely to form interprofessional ties. Health management and support personnel ties were 94% interprofessional while ties among nurses were 60% interprofessional. Nurses and other health professionals were significantly less likely than physicians to form ties. Nurses were 1.64 times more likely to communicate with nurses than non-nurses (OR = 1.64, 95% CI: 1.01-2.66); there was no significant role homophily for physicians, other health professionals, or health management and support personnel. Understanding communication networks in healthcare teams is an early step in understanding how teams work together to provide care; future work should evaluate the types and quality of interactions between members of interprofessional healthcare teams.
Fission cross section calculations of actinides with EMPIRE code
Energy Technology Data Exchange (ETDEWEB)
Sin, M.; Oblozinsky, P.; Herman,M.; Capote,R.
2010-04-30
The cross sections of the neutron induced reactions on {sup 233,234,236}U, {sup 237}Np, {sup 238,242}Pu, {sup 241,243}Am, {sup 242,246}Cm carried out in the energy range 1 keV-20 MeV with EMPIRE code are presented, emphasizing the fission channel. Beside a consistent, accurate set of evaluations, the paper contains arguments supporting the choice of the reaction models and input parameters. A special attention is paid to the fission parameters and their uncertainties.
WW production cross section at 13 TeV
Dutta, Baishali; The ATLAS collaboration
2017-01-01
Precise measurement of $W^{+}W^{-}$ production process empowers our understanding of Standard Model and also probes new physics phenomena at higher energies. This talk presents the total and fiducial cross section measurement of $W^{+}W^{-}$ process at a centre-of-energy $\\sqrt{s}$ = 13 TeV with the data collected by the ATLAS detector in 2015. The events are selected in the leptonic decay channel i.e both W decaying into two leptons (electrons, muons) and associated missing transverse momentum.
α scattering and α -induced reaction cross sections of 64Zn at low energies
Ornelas, A.; Mohr, P.; Gyürky, Gy.; Elekes, Z.; Fülöp, Zs.; Halász, Z.; Kiss, G. G.; Somorjai, E.; Szücs, T.; Takács, M. P.; Galaviz, D.; Güray, R. T.; Korkulu, Z.; Özkan, N.; Yalçın, C.
2016-11-01
Background: α -nucleus potentials play an essential role for the calculation of α -induced reaction cross sections at low energies in the statistical model. Uncertainties of these calculations are related to ambiguities in the adjustment of the potential parameters to experimental elastic scattering angular distributions and to the energy dependence of the effective α -nucleus potentials. Purpose: The present work studies the total reaction cross section σreac of α -induced reactions at low energies which can be determined from the elastic scattering angular distribution or from the sum over the cross sections of all open nonelastic channels. Method: Elastic and inelastic 64Zn(α ,α )64Zn angular distributions were measured at two energies around the Coulomb barrier, at 12.1 and 16.1 MeV. Reaction cross sections of the (α ,γ ) , (α ,n ) , and (α ,p ) reactions were measured at the same energies using the activation technique. The contributions of missing nonelastic channels were estimated from statistical model calculations. Results: The total reaction cross sections from elastic scattering and from the sum of the cross sections over all open nonelastic channels agree well within the uncertainties. This finding confirms the consistency of the experimental data. At the higher energy of 16.1 MeV, the predicted significant contribution of compound-inelastic scattering to the total reaction cross section is confirmed experimentally. As a by-product it is found that most recent global α -nucleus potentials are able to describe the reaction cross sections for 64Zn around the Coulomb barrier. Conclusions: Total reaction cross sections of α -induced reactions can be well determined from elastic scattering angular distributions. The present study proves experimentally that the total cross section from elastic scattering is identical to the sum of nonelastic reaction cross sections. Thus, the statistical model can reliably be used to distribute the total reaction
Tran, D T; Nguyen, T T; Tanihata, I; Aoi, N; Ayyad, Y; Chan, P Y; Fukuda, M; Hashimoto, T; Hoang, T H; Ideguchi, E; Inoue, A; Kawabata, T; Khiem, L H; Lin, W P; Matsuta, K; Mihara, M; Momota, S; Nagae, D; Nguyen, N D; Nishimura, D; Ozawa, A; Ren, P P; Sakaguchi, H; Tanaka, J; Takechi, M; Terashima, S; Wada, R; Yamamoto, T
2016-01-01
We have measured for the first time the charge-changing cross sections ($\\sigma_{\\text{CC}}$) of $^{12-16}$C on a $^{12}$C target at energies below $100A$ MeV. To analyze these low-energy data, we have developed a finite-range Glauber model with a global parameter set within the optical-limit approximation which is applicable to reaction cross section ($\\sigma_{\\text{R}}$) and $\\sigma_{\\text{CC}}$ measurements at incident energies from 10$A$ to $2100A$ MeV. Adopting the proton-density distribution of $^{12}$C known from the electron-scattering data, as well as the bare total nucleon-nucleon cross sections, and the real-to-imaginary-part ratios of the forward proton-proton elastic scattering amplitude available in the literatures, we determine the energy-dependent slope parameter $\\beta_{\\rm pn}$ of the proton-neutron elastic differential cross section so as to reproduce the existing $\\sigma_{\\text{R}}$ and interaction-cross-section data for $^{12}$C+$^{12}$C over a wide range of incident energies. The Glauber...
Neutron Cross Section Covariances for Structural Materials and Fission Products
Hoblit, S.; Cho, Y.-S.; Herman, M.; Mattoon, C. M.; Mughabghab, S. F.; Obložinský, P.; Pigni, M. T.; Sonzogni, A. A.
2011-12-01
We describe neutron cross section covariances for 78 structural materials and fission products produced for the new US evaluated nuclear reaction library ENDF/B-VII.1. Neutron incident energies cover full range from 10 eV to 20 MeV and covariances are primarily provided for capture, elastic and inelastic scattering as well as (n,2n). The list of materials follows priorities defined by the Advanced Fuel Cycle Initiative, the major application being data adjustment for advanced fast reactor systems. Thus, in addition to 28 structural materials and 49 fission products, the list includes also 23Na which is important fast reactor coolant. Due to extensive amount of materials, we adopted a variety of methodologies depending on the priority of a specific material. In the resolved resonance region we primarily used resonance parameter uncertainties given in Atlas of Neutron Resonances and either applied the kernel approximation to propagate these uncertainties into cross section uncertainties or resorted to simplified estimates based on integral quantities. For several priority materials we adopted MF32 covariances produced by SAMMY at ORNL, modified by us by adding MF33 covariances to account for systematic uncertainties. In the fast neutron region we resorted to three methods. The most sophisticated was EMPIRE-KALMAN method which combines experimental data from EXFOR library with nuclear reaction modeling and least-squares fitting. The two other methods used simplified estimates, either based on the propagation of nuclear reaction model parameter uncertainties or on a dispersion analysis of central cross section values in recent evaluated data files. All covariances were subject to quality assurance procedures adopted recently by CSEWG. In addition, tools were developed to allow inspection of processed covariances and computed integral quantities, and for comparing these values to data from the Atlas and the astrophysics database KADoNiS.
Neutron Cross Section Covariances for Structural Materials and Fission Products
Energy Technology Data Exchange (ETDEWEB)
Hoblit, S.; Hoblit,S.; Cho,Y.-S.; Herman,M.; Mattoon,C.M.; Mughabghab,S.F.; Oblozinsky,P.; Pigni,M.T.; Sonzogni,A.A.
2011-12-01
We describe neutron cross section covariances for 78 structural materials and fission products produced for the new US evaluated nuclear reaction library ENDF/B-VII.1. Neutron incident energies cover full range from 10{sup -5} eV to 20 MeV and covariances are primarily provided for capture, elastic and inelastic scattering as well as (n,2n). The list of materials follows priorities defined by the Advanced Fuel Cycle Initiative, the major application being data adjustment for advanced fast reactor systems. Thus, in addition to 28 structural materials and 49 fission products, the list includes also {sup 23}Na which is important fast reactor coolant. Due to extensive amount of materials, we adopted a variety of methodologies depending on the priority of a specific material. In the resolved resonance region we primarily used resonance parameter uncertainties given in Atlas of Neutron Resonances and either applied the kernel approximation to propagate these uncertainties into cross section uncertainties or resorted to simplified estimates based on integral quantities. For several priority materials we adopted MF32 covariances produced by SAMMY at ORNL, modified by us by adding MF33 covariances to account for systematic uncertainties. In the fast neutron region we resorted to three methods. The most sophisticated was EMPIRE-KALMAN method which combines experimental data from EXFOR library with nuclear reaction modeling and least-squares fitting. The two other methods used simplified estimates, either based on the propagation of nuclear reaction model parameter uncertainties or on a dispersion analysis of central cross section values in recent evaluated data files. All covariances were subject to quality assurance procedures adopted recently by CSEWG. In addition, tools were developed to allow inspection of processed covariances and computed integral quantities, and for comparing these values to data from the Atlas and the astrophysics database KADoNiS.
Monte Carlo simulation of phonon transport in variable cross-section nanowires
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
A dedicated Monte Carlo (MC) model is proposed to investigate the mechanism of phonon transport in variable cross-section silicon nanowires (NWs). Emphasis is placed on understanding the thermal rectification effect and thermal conduction in tapered cross-section and incremental cross-section NWs. In the simulations, both equal and unequal heat input conditions are discussed. Under the latter condition, the tapered cross-section NW has a more prominent thermal rectification effect. Additionally, the capacity of heat conduction in the tapered cross-section NW is always higher than that of the incremental one. Two reasons may be attributed to these behaviors: one is their different boundary conditions and the other is their different volume distribution. Although boundary scattering plays an important role in nanoscale structures, the results suggest the influence of boundary scattering on heat conduction is less obvious than that of volume distribution in NWs with variable cross-sections.
Ahmed, Syed Masud; Naher, Nahitun; Hossain, Tarek; Rawal, Lal Bahadur
2017-01-01
The private retail drug shops market in Bangladesh is largely unregulated and unaccountable, giving rise to irrational use of drugs and high Out-of-pocket expenditure on health. These shops are served by salespersons with meagre or no formal training in dispensing. This facility-based cross-sectional study was undertaken to investigate how the drug shops currently operate vis-a-vis the regulatory regime including dispensing practices of the salespersons, for identifying key action points to develop an accredited model for Bangladesh. About 90 rural and 21 urban retail drug shops from seven divisions were included in the survey. The salespersons were interviewed for relevant information, supplemented by qualitative data on perceptions of the catchment community as well as structured observation of client-provider interactions from a sub-sample. In 76% of the shops, the owner and the salesperson was the same person, and >90% of these were located within 30 min walking distance from a public sector health facility. The licensing process was perceived to be a cumbersome, lengthy, and costly process. Shop visit by drug inspectors were brief, wasn't structured, and not problem solving. Only 9% shops maintained a stock register and 10% a drug sales record. Overall, 65% clients visited drug shops without a prescription. Forty-nine percent of the salespersons had no formal training in dispensing and learned the trade through apprenticeship with fellow drug retailers (42%), relatives (18%), and village doctors (16%) etc. The catchment population of the drug shops mostly did not bother about dispensing training, drug shop licensing and buying drugs without prescription. Observed client-dispenser interactions were found to concentrate mainly on financial transaction, unless, the client pro-actively sought advice regarding the use of the drug. Majority of the drug shops studied are run by salespersons who have informal 'training' through apprenticeship. Visiting drug shops
Institute of Scientific and Technical Information of China (English)
ZHANG Jun-Jie; HU Bi-Tao
2011-01-01
In this work,the program Cindy was modified to calculate the formation cross section of each energy level of residual nucleus 181W resulting from the reaction 181Ta(p,nγ)181 W.The concerned cross sections calculated at proton energy Ep=4.5-8.5 MeV agreed well with experimental results.The influence of the spin cut-off parameter in the energy level density model on the cross section was studied.The obtained results show that the influence of spin cut-off is obvious for lower energy levels.
Cross-Sectional Drawing Techniques And The Artist
Berry, William A.
1980-07-01
Although Democritus, a Greek pholosopher of the fifth century B.C. described the use of cross-sections in analyzing a solid form, this method was not extensively developed in art until the Renaissance. The earliest treatise documenting the integration of the cross-section and linear perspective is Piero della Francesca's De prospective pingendi (c. 1480), in which a drawing of the human head is mathematically conceived and plotted by means of cross-section contours. Piero's method anticipates contemporary biostereometric techniques and current theories of visual perception. Outside of theoretical treatises the complete cross-section rarely occurs in art, though certain pictorial elements such as the religious halo can be interpreted as cross-sections. The chan-ging representation of the halo in art of the Medieval, Renaissance and Baroque periods parallels the development of the artist's concepts and techniques for representing form and space. During the Renaissance and Baroque periods the widespread use of contour hatching, a drawing technique based on the cross-section, indicates that the cross-section concept has played a greater role in pictorial representation than has generally been recognized.
Rosenbluth separation of the $\\pi^0$ electroproduction cross section
Defurne, M; Albataineh, H; Allada, K; Aniol, K A; Bellini, V; Benali, M; Boeglin, W; Bertin, P; Brossard, M; Camsonne, A; Canan, M; Chandavar, S; Chen, C; Chen, J -P; de Jager, C W; de Leo, R; Desnault, C; Deur, A; Fassi, L El; Ent, R; Flay, D; Friend, M; Fuchey, E; Frullani, S; Garibaldi, F; Gaskell, D; Giusa, A; Glamazdin, O; Golge, S; Gomez, J; Hansen, O; Higinbotham, D; Holmstrom, T; Horn, T; Huang, J; Huang, M; Hyde, C E; Iqbal, S; Itard, F; Kang, H; Kelleher, A; Keppel, C; Koirala, S; Korover, I; LeRose, J J; Lindgren, R; Long, E; Magne, M; Mammei, J; Margaziotis, D J; Markowitz, P; Jimenez-Arguello, A Marti; Meddi, F; Meekins, D; Michaels, R; Mihovilovic, M; Camacho, C Munoz; Nadel-Turonski, P; Nuruzzaman, N; Paremuzyan, R; Puckett, A; Punjabi, V; Qiang, Y; Rakhman, A; Rashad, M N H; Riordan, S; Roche, J; Russo, G; Sabati, F; Saenboonruang, K; Saha, A; Sawatzky, B; Selvy, L; Shahinyan, A; Sirca, S; Solvignon, P; Sperduto, M L; Subedi, R; Sulkosky, V; Sutera, C; Tobias, W A; Urciuoli, G M; Wang, D; Wojtsekhowski, B; Yao, H; Ye, Z; Zafar, A; Zhan, X; Zhang, J; Zhao, B; Zhao, Z; Zheng, X; Zhu, P
2016-01-01
We present deeply virtual $\\pi^0$ electroproduction cross-section measurements at $x_B$=0.36 and three different $Q^2$--values ranging from 1.5 to 2 GeV$^2$, obtained from experiment E07-007 that ran in the Hall A at Jefferson Lab. The Rosenbluth technique was used to separate the longitudinal and transverse responses. Results demonstrate that the cross section is dominated by its transverse component, and thus is far from the asymptotic limit predicted by perturbative Quantum Chromodynamics. An indication of a non-zero longitudinal contribution is provided by the interference term $\\sigma_{LT}$ also measured. Results are compared with several models based on the leading twist approach of Generalized Parton Distributions (GPDs). In particular, a fair agreement is obtained with models where the scattering amplitude is described by a convolution of chiral-odd (transversity) GPDs of the nucleon with the twist-3 pion distribution amplitude. Therefore, neutral pion electroproduction may offer the exciting possibil...
Measuring astrophysically relevant 36Cl production cross sections
Anderson, Tyler; Skulski, Michael; Ostdiek, Karen; Lu, Wenting; Clark, Adam; Nelson, Austin; Beard, Mary; Collon, Philippe
2016-09-01
The short-lived radionuclide 36Cl (t1 / 2 = 0 . 301 Ma) is known to have existed in the Early Solar System (ESS), and evaluating its production sources can lead to better understanding of the processes taking place in ESS formation and their timescales. The X-wind model is used to explain 36Cl production via solar energetic particles from the young Sun, but is lacking empirical data for many relevant reactions. Bowers et al. (2013) measured the 33S(α,p)36Cl cross section at various energies in the range of 0.70-2.42 MeV/A, and found them to be systematically under predicted by Hauser-Feshbach statistical model codes TALYS and NON-SMOKER, highlighting the need for more empirical data for these cross sections. Recent results of the re-measurement of the 33S(α,p)36Cl reaction, providing greater coverage of the same energy range as Bowers et al., will be presented. Future plans for measurement of other 36Cl producing reactions will also be discussed.
Rosenbluth Separation of the π0 Electroproduction Cross Section
Defurne, M.; Mazouz, M.; Ahmed, Z.; Albataineh, H.; Allada, K.; Aniol, K. A.; Bellini, V.; Benali, M.; Boeglin, W.; Bertin, P.; Brossard, M.; Camsonne, A.; Canan, M.; Chandavar, S.; Chen, C.; Chen, J.-P.; de Jager, C. W.; de Leo, R.; Desnault, C.; Deur, A.; El Fassi, L.; Ent, R.; Flay, D.; Friend, M.; Fuchey, E.; Frullani, S.; Garibaldi, F.; Gaskell, D.; Giusa, A.; Glamazdin, O.; Golge, S.; Gomez, J.; Hansen, O.; Higinbotham, D.; Holmstrom, T.; Horn, T.; Huang, J.; Huang, M.; Huber, G. M.; Hyde, C. E.; Iqbal, S.; Itard, F.; Kang, Ho.; Kang, Hy.; Kelleher, A.; Keppel, C.; Koirala, S.; Korover, I.; LeRose, J. J.; Lindgren, R.; Long, E.; Magne, M.; Mammei, J.; Margaziotis, D. J.; Markowitz, P.; Martí Jiménez-Argüello, A.; Meddi, F.; Meekins, D.; Michaels, R.; Mihovilovic, M.; Muangma, N.; Muñoz Camacho, C.; Nadel-Turonski, P.; Nuruzzaman, N.; Paremuzyan, R.; Puckett, A.; Punjabi, V.; Qiang, Y.; Rakhman, A.; Rashad, M. N. H.; Riordan, S.; Roche, J.; Russo, G.; Sabatié, F.; Saenboonruang, K.; Saha, A.; Sawatzky, B.; Selvy, L.; Shahinyan, A.; Sirca, S.; Solvignon, P.; Sperduto, M. L.; Subedi, R.; Sulkosky, V.; Sutera, C.; Tobias, W. A.; Urciuoli, G. M.; Wang, D.; Wojtsekhowski, B.; Yao, H.; Ye, Z.; Zana, L.; Zhan, X.; Zhang, J.; Zhao, B.; Zhao, Z.; Zheng, X.; Zhu, P.; Jefferson Lab Hall A Collaboration
2016-12-01
We present deeply virtual π0 electroproduction cross-section measurements at xB=0.36 and three different Q2 values ranging from 1.5 to 2 GeV 2 , obtained from Jefferson Lab Hall A experiment E07-007. The Rosenbluth technique is used to separate the longitudinal and transverse responses. Results demonstrate that the cross section is dominated by its transverse component and, thus, is far from the asymptotic limit predicted by perturbative quantum chromodynamics. Nonetheless, an indication of a nonzero longitudinal contribution is provided by the measured interference term σL T. Results are compared with several models based on the leading-twist approach of generalized parton distributions (GPDs). In particular, a fair agreement is obtained with models in which the scattering amplitude includes convolution terms of chiral-odd (transversity) GPDs of the nucleon with the twist-3 pion distribution amplitude. This experiment, together with previous extensive unseparated measurements, provides strong support to the exciting idea that transversity GPDs can be accessed via neutral pion electroproduction in the high-Q2 regime.
Ionization and capture in water: a multi-differential cross sections study
Champion, Christophe; Galassi, Mariel E.; Weck, Philippe F.; Fojón, Omar; Hanssen, Jocelyn; Rivarola, Roberto D.
2012-11-01
Two quantum mechanical models (CB1 and CDW-EIS) are here presented to provide accurate multiple differential and total cross sections for describing the two most important ionizing processes, namely, ionization and capture induced by heavy charged particles in water. A detailed study of the influence of the target description on the cross section calculations is also provided.
Nonlinear Collapse of General Thin-Walled Cross-Sections Under Pure Bending
DEFF Research Database (Denmark)
Couturier, Philippe; Krenk, Steen
2016-01-01
Thin-walled beams exhibit a nonlinear response to bending moments due to the progressive flattening of the crosssection, a behavior commonly referred to as the Brazier effect. Most approaches to model this effect are limited to either circular cross-sections or to cross-sections made of isotropic...
Cross section to multiplicity ratios at very high energy
Energy Technology Data Exchange (ETDEWEB)
Block, M.M. [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Stodolsky, L. [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, 80805 München (Germany)
2014-06-27
Recent data from the LHC makes it possible to examine an old speculation that at very high energy the total multiplicity and the cross section in elementary particle interactions vary in parallel with energy. Using fits incorporating the new data, it appears that the ratios of the total, elastic, and inelastic cross sections to the average multiplicity N can in fact approach constants at very high energy. The approach to the limit is however quite slow for the total and inelastic cross sections and is not yet reached at LHC energies. The elastic ratio σ{sup el}/N at 7 TeV, however, is not far from its asymptotic value.
An evaluation of wind turbine blade cross section analysis techniques.
Energy Technology Data Exchange (ETDEWEB)
Paquette, Joshua A.; Griffith, Daniel Todd; Laird, Daniel L.; Resor, Brian Ray
2010-03-01
The blades of a modern wind turbine are critical components central to capturing and transmitting most of the load experienced by the system. They are complex structural items composed of many layers of fiber and resin composite material and typically, one or more shear webs. Large turbine blades being developed today are beyond the point of effective trial-and-error design of the past and design for reliability is always extremely important. Section analysis tools are used to reduce the three-dimensional continuum blade structure to a simpler beam representation for use in system response calculations to support full system design and certification. One model simplification approach is to analyze the two-dimensional blade cross sections to determine the properties for the beam. Another technique is to determine beam properties using static deflections of a full three-dimensional finite element model of a blade. This paper provides insight into discrepancies observed in outputs from each approach. Simple two-dimensional geometries and three-dimensional blade models are analyzed in this investigation. Finally, a subset of computational and experimental section properties for a full turbine blade are compared.
Radar cross section measurements using terahertz waves
DEFF Research Database (Denmark)
Iwaszczuk, Krzysztof; Heiselberg, Henning; Jepsen, Peter Uhd
2010-01-01
in a lithium niobate crystal with application of the tilted wave front method, resulting in high electric field THz pulses with a broad band spectrum from 100 GHz up to 4 THz. The corresponding wave lengths are two orders of magnitude smaller than normal radars and we therefore use scale models of size 5-10 cm...
Propionaldehyde infrared cross-sections and band strengths
Köroğlu, Batikan; Loparo, Zachary; Nath, Janardan; Peale, Robert E.; Vasu, Subith S.
2015-02-01
The use of oxygenated biofuels reduces the greenhouse gas emissions; however, they also result in increased toxic aldehyde by-products, mainly formaldehyde, acetaldehyde, acrolein, and propionaldehyde. These aldehydes are carcinogenic and/or toxic and therefore it is important to understand their formation and destruction pathways in combustion and atmospheric systems. Accurate information about their infrared cross-sections and integrated strengths are crucially needed for development of quantitative detection schemes and modeling tools. Critical to the development of such diagnostics are accurate characterization of the absorption features of these species. In this study, the gas phase infrared spectra of propionaldehyde (also called propanal, CH3-CH2-CHO), a saturated three carbon aldehyde found in the exhaust emissions of biodiesel or diesel fuels, was studied using high resolution Fourier Transform Infrared (FTIR) spectroscopy over the wavenumber range of 750-3300 cm-1 and at room temperature 295 K. The absorption cross sections of propionaldehyde were recorded at resolutions of 0.08 and 0.096 cm-1 and at seven different pressures (4-33 Torr). The calculated band-strengths were reported and the integrated band intensity results were compared with values taken from the Pacific Northwest National Laboratory (PNNL) database (showing less than 2% discrepancy). The peak positions of the 19 different vibrational bands of propionaldehyde were also compared with previous studies taken at a lower resolution of 1 cm-1. To the best of our knowledge, the current FTIR measurements provide the first highest resolution infrared cross section data for propionaldehyde.
Hadronic Production of Ψ(2S) Cross section and Polarization
Energy Technology Data Exchange (ETDEWEB)
Chung, Kwangzoo [Carnegie Mellon Univ., Pittsburgh, PA (United States)
2008-05-01
The hadronic production cross section and the polarization of Ψ(2S) meson are measured by using the data from p$\\bar{p}$ collisions at √s = 1.96 TeV collected by the Collider Detector at Fermilab. The datasets used correspond to integrated luminosity of 1.1 fb^{-1} and 800 pb^{-1}, respectively. The decay Ψ(2S) → μ^{+}μ^{-} is used to reconstruct Ψ(2S) mesons in the rapidity range |y(Ψ(2S))| < 0.6. The coverage of the p_{T} range is 2.0 GeV/c ≤ p_{T} (Ψ(2S)) < 30 GeV/c for the cross section analysis and pT ≥ 5 GeV/c for the polarization analysis. For events with p_{T} (Ψ(2S)) > 2 GeV/c the integrated inclusive cross section multiplied by the branching ratio for dimuon decay is 3.17 ± 0.04 ± 0.28 nb . This result agrees with the CDF Run I measurement considering the increased center-of-mass energy from 1.8 TeV to 1.96 TeV. The polarization of the promptly produced Ψ(2S) mesons is found to be increasingly longitudinal as p_{T} increases from 5 GeV/c to 30 GeV/c. The result is compared to contemporary theory models.
Energy Technology Data Exchange (ETDEWEB)
Pater, P; Seuntjens, J; El Naqa, I [McGill University, Montreal, Quebec (Canada)
2014-06-15
Purpose: To obtain probability distributions of various DNA damage types as a function of the incident electron kinetic energy. Methods: Using Geant4-DNA electron ionization cross-sections, we calculated path length distributions for electrons of energies between 10 eV and 1 MeV, defined as the length between two subsequent interactions. These path lengths were then convolved with probability distributions for the creation of same-strand damage, opposite-strand damage, clustered damage, isolated damage, and same DNA strand target damage. These probability distributions of DNA damage were obtained by a Monte Carlo routine calculating probabilities of interaction in DNA targets inside a nucleosome geometrical model. Results represent the probability of a secondary electron, initially created inside a DNA strand target, of undergoing its next interaction: (1) in the opposite strand (DSB), (2) in the same strand (SSB+), (3) in either the opposite or same-strand (clustered), (4) in the same DNA target (multiple-hit) or (5) more than 10 base pairs away (isolated). Results: Electrons with kinetic energy between 50 and 250 eV have a maximal probability of creating DSB, SSB+, clustered damage and multiple-hits in the same target The probabilities for these damage patterns have values of 2.5%, 4.3%, 6.7% and 5.4%, respectively. Isolated damage is most probable between 700 eV to 900 eV with a probability of 0.2%. Conclusion: We obtained DNA damage probability distributions as a function of electron incident energy. We showed that electrons with kinetic energies between 50 and 250 eV have the highest probability of producing complex forms of DNA damage (DSB, SSB+). We also showed that a double ionization within the same DNA target is the most frequent outcome occurring 5% of the time. It is expected that electron slowing down spectra can be convolved with our formalism to calculate source specific DNA damage patterns. Research grants from governments of Canada and Quebec. PP
Directory of Open Access Journals (Sweden)
Dupe Hambolu
Full Text Available BACKGROUND: Bovine Tuberculosis (bTB is still a serious public health threat in developing countries. The aim of this study is to determine the social and cognitive factors predicting one of the risk behaviours amongst meat handlers in Nigeria, namely, eating Fuku Elegusi. This is the practice of eating the visibly infected parts of the lung in-order to convince customers to buy meat. The study is guided by the health belief model (HBM. METHODS: This is a cross-sectional study of 349 randomly selected meat handlers in Oko-Oba Abattoir, in Lagos State. Descriptive statistics and multiple logistic regression analysis were employed to determine perceptions and prevalence of risk behaviours and to identify predictors of eating Fuku Elegusi. RESULTS: Just over a quarter (28.1% of the study participants knew that eating Fuku Elegusi could be a source of bTB in humans. The prevalence of eating Fuku Elegusi was found to be 22%. Across all knowledge indicators related to bTB, those who don't eat Fuku Elegusi exhibited better knowledge. Strong predictors of eating Fuku Elegusi were: being male (OR: 2.39, 95% CI: 1.10 to 5.19; p = 0.03, not knowing that eating Fuku Elegusi exposes to bTB (OR: 3.72, 95% CI: 1.69 to 8.22; p = 0.001, and the perception that one cannot sell meat without tasting it (perceived barrier (OR: 1.35, 95% CI: 1.13 to 1.60; p = 0.001. Lower risk of eating Fuku Elegusi was predicted by perceived susceptibility to bTB due to another risk behaviour, namely, not washing hands after handling meat (OR: 0.78, 95% CI: 0.64 to 0.96; p-value = 0.021. Television and radio were the most acceptable media for TB prevention messages (78.5% and 75.6% respectively. CONCLUSION: Meat handlers in developing countries bear high risk to bTB owing to prevailing social and cognition determinants. Findings were largely consistent with the propositions of HBM.
Plasma Polarization Spectroscopy and collision cross sections
Energy Technology Data Exchange (ETDEWEB)
Fujimoto, Takashi; Nakai, Manabu [Dept. of Engineering Physics and Mechanics, Graduate School of Engineering, Kyoto Univ. (Japan)
2000-01-01
In Plasma Polarization Spectroscopy (PPS), we observe the polarized spectral lines emitted from a plasma. For berylliumlike oxygen lines from a tokamak plasma the polarization feature is interpreted as due to the anisotropic velocity distribution of electrons which excite the ions. In this interpretation in terms of the population-alignment collisional-radiative (PACR) model various collision processes are involved concerning the population and the alignment, e.g., transfer of the alignment, and the coherence by collisional excitation and production of an alignment from a population by elastic collisions. These latter processes are little known so far. (author)
Total cross-section measurements progress in nuclear physics
Giacomelli, G; Mulvey, J H
2013-01-01
Total Cross-Section Measurements discusses the cross-sectional dimensions of elementary hadron collisions. The main coverage of the book is the resonance and high energy area of the given collision. A section of the book explains in detail the characteristic of a resonance region. Another section is focused on the location of the high energy region of collision. Parts of the book define the meaning of resonance in nuclear physics. Also explained are the measurement of resonance and the identification of the area where the resonance originates. Different experimental methods to measure the tota
Energy Technology Data Exchange (ETDEWEB)
Walsh, Jonathan A., E-mail: walshjon@mit.edu [Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 24-107, Cambridge, MA 02139 (United States); Palmer, Todd S. [Department of Nuclear Engineering and Radiation Health Physics, Oregon State University, 116 Radiation Center, Corvallis, OR 97331 (United States); Urbatsch, Todd J. [XTD-IDA: Theoretical Design, Integrated Design and Assessment, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
2015-12-15
Highlights: • Generation of discrete differential scattering angle and energy loss cross sections. • Gauss–Radau quadrature utilizing numerically computed cross section moments. • Development of a charged particle transport capability in the Milagro IMC code. • Integration of cross section generation and charged particle transport capabilities. - Abstract: We investigate a method for numerically generating discrete scattering cross sections for use in charged particle transport simulations. We describe the cross section generation procedure and compare it to existing methods used to obtain discrete cross sections. The numerical approach presented here is generalized to allow greater flexibility in choosing a cross section model from which to derive discrete values. Cross section data computed with this method compare favorably with discrete data generated with an existing method. Additionally, a charged particle transport capability is demonstrated in the time-dependent Implicit Monte Carlo radiative transfer code, Milagro. We verify the implementation of charged particle transport in Milagro with analytic test problems and we compare calculated electron depth–dose profiles with another particle transport code that has a validated electron transport capability. Finally, we investigate the integration of the new discrete cross section generation method with the charged particle transport capability in Milagro.
Measurement of Heavy Quark cross-sections at CDF
Energy Technology Data Exchange (ETDEWEB)
Annovi, Alberto; /Frascati
2007-09-01
Abstract: The measurement of heavy quark cross-sections provides important tests of the QCD theory. This paper reviews recent measurements of single b-quark and correlated b-quark cross-sections at CDF. Two new measurements of the single b-quark production at CDF agree with the first result from CDF Run II. This clarifies the experimental situation and confirms the recent agreement of theoretical prediction with data. A new measurement of the correlated b{bar b} cross-section with dimuon events at CDF is presented. It agrees with theory and it does not confirm the anomalously large b{bar b} cross-section seen in Run I by CDF and D0 in dimuon events.
Theoretical Studies on Photoionization Cross Sections of Solid Gold
Institute of Scientific and Technical Information of China (English)
MA Xiao-Guang; SUN Wei-Guo; CHENG Yah-Song
2005-01-01
Accurate expression for photoabsorption (photoionization) cross sections of high density system proposed recently is used to study the photoionization of solid gold. The results show that the present theoretical photoionization cross sections have good agreement both in structure and in magnitude with the experimental results of gold crystal.The studies also indicate that both the real part ε'and the imaginary part ε" of the complex dielectric constant ε,and the dielectric influence function of a nonideal system have rich structures in low energy side with a range about 50 eV, and suggest that the influence of particle interactions of surrounding particles with the photoionized particle on the photoionization cross sections can be easily investigated using the dielectric influence function. The electron overlap effects are suggested to be implemented in the future studies to improve the accuracy of theoretical photoionization cross sections of a solid system.
Fully differential cross sections for heavy particle impact ionization
Energy Technology Data Exchange (ETDEWEB)
McGovern, M; Walters, H R J [Department of Applied Mathematics and Theoretical Physics, Queen' s University, Belfast BT7 1NN (United Kingdom); Assafrao, D; Mohallem, J R [Laboratorio de Atomos e Moleculas Especiais, Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, P.O Box 702, 30123-970 Belo Horizonte, MG (Brazil); Whelan, Colm T, E-mail: mmcgovern06@qub.ac.u [Department of Physics, Old Dominion University, Norfolk, VA 23529-0116 (United States)
2009-11-15
We describe a procedure for extracting fully differential ionization cross sections from an impact parameter coupled pseudostate treatment of the collision. Some examples from antiproton impact ionization of atomic Hydrogen are given.
differential cross sections of electron silver scattering at varying ...
African Journals Online (AJOL)
occur in quantum mechanics, quantum electrodynamics and partial wave expansion. The main ... The differential cross section is the main observable in quantum scattering experiments. .... program at run-time and have the exertion. DAT.
Trilogy of LHC Higgs Cross Section Working Group
Tanaka, R; The ATLAS collaboration
2013-01-01
Slide shown at Aspen 2013 - Higgs Quo Vadis, March 10-15, 2013, Aspen, CO, USA. The activity of LHC Higgs Cross Section Woking Group was reported putting emphasis on current theoretical issues in Higgs physics towards precision Higgs measurements.
Total cross sections for ultracold neutrons scattered from gases
Seestrom, S. J.; Adamek, E. R.; Barlow, D.; Blatnik, M.; Broussard, L. J.; Callahan, N. B.; Clayton, S. M.; Cude-Woods, C.; Currie, S.; Dees, E. B.; Fox, W.; Hoffbauer, M.; Hickerson, K. P.; Holley, A. T.; Liu, C.-Y.; Makela, M.; Medina, J.; Morley, D. J.; Morris, C. L.; Pattie, R. W.; Ramsey, J.; Roberts, A.; Salvat, D. J.; Saunders, A.; Sharapov, E. I.; Sjue, S. K. L.; Slaughter, B. A.; Walstrom, P. L.; Wang, Z.; Wexler, J.; Womack, T. L.; Young, A. R.; Vanderwerp, J.; Zeck, B. A.
2017-01-01
We have followed up on our previous measurements of upscattering of ultracold neutrons (UCNs) from a series of gases by making measurements of total cross sections on the following gases hydrogen, ethane, methane, isobutene, n -butane, ethylene, water vapor, propane, neopentane, isopropyl alcohol, and 3He . The values of these cross sections are important for estimating the loss rate of trapped neutrons due to residual gas and are relevant to neutron lifetime measurements using UCNs. The effects of the UCN velocity and path-length distributions were accounted for in the analysis using a Monte Carlo transport code. Results are compared to our previous measurements and with the known absorption cross section for 3He scaled to our UCN energy. We find that the total cross sections for the hydrocarbon gases are reasonably described by a function linear in the number of hydrogen atoms in the molecule.
Highlights of top quark cross-section measurements at ATLAS
Berta, Peter; The ATLAS collaboration
2017-01-01
The highlights of the measurements of top quark production in proton-proton collisions at the Large Hadron Collider with the ATLAS detector are presented. The inclusive measurements of the top-pair production cross section have reached high precision and are compared to the best available theoretical calculations. The differential cross section measurements, including results using boosted top quarks, probe our understanding of top-pair production in the TeV regime. The results are compared to Monte Carlo generators implementing LO and NLO matrix elements matched with parton showers. Measurements of the single top quark production cross section are presented in the t-channel and s-channel, and with associated production with a W boson. For the t-channel production, results on the ratio between top quark and antitop quark production cross sections and differential measurements are also included.
Top quark pair cross section prospects in ATLAS
Gaponenko, Andrei
2009-01-01
The observation of the top quark will be an important milestone in ATLAS. This talk reviews methods that ATLAS plans to use to observe the top quark pair production process and measure its cross section.
Evaluation of nuclear reaction cross section of some isotopes of ...
African Journals Online (AJOL)
Evaluation of nuclear reaction cross section of some isotopes of plutonium at energy range ... Nigerian Journal of Chemical Research ... Their choice is as a result of their importance in the modern day nuclear reactor and the energy range 10 ...
Longitudinal Vibrations of Rheological Rod With Variable Cross Section
Institute of Scientific and Technical Information of China (English)
Katica（Stevanovic）HEDRIH; AleksandarFILIPOVSKI
1999-01-01
Longitudinal vibrations of rheological rod with variable cross section are examined.Particular solutions and eigenfunction are accomplished for natural vibrations of the rod with hereditary material of standard hereditary body.Some examples are given.
Charm meson scattering cross sections by pion and rho meson
Lin Zi Wei; Ko, C M
2001-01-01
Using the local flavor SU(4) gauge invariance in the limit of vanishing vector-meson masses, we extend our previous study of charm-meson scattering cross sections by pion and rho meson, which is based only on the pseudoscalar-pseudoscalar-vector meson couplings, to include also contributions from the couplings among three vector mesons and among four particles. We find that diagrams with light-meson exchanges usually dominate the cross sections. For the processes considered previously, the additional interactions lead only to diagrams involving charm-meson exchanges and contact interactions, and the cross sections for these processes are thus not much affected. Nevertheless, these additional interactions introduce new processes with light-meson exchanges and increase significantly the total scattering cross sections of charm mesons by pion and rho meson.
Fast calculation method of complex space targets' optical cross section.
Han, Yi; Sun, Huayan; Li, Yingchun; Guo, Huichao
2013-06-10
This paper utilizes the optical cross section (OCS) to characterize the optical scattering characteristics of a space target under the conditions of Sun lighting. We derive the mathematical expression of OCS according to the radiometric theory, and put forward a fast visualization calculation method of complex space targets' OCS based on an OpenGL and 3D model. Through the OCS simulation of Lambert bodies (cylinder and sphere), the computational accuracy and speed of the algorithm were verified. By using this method, the relative error for OCS will not exceed 0.1%, and it only takes 0.05 s to complete a complex calculation. Additionally, we calculated the OCS of three actual satellites with bidirectional reflectance distribution function model parameters in visible bands, and results indicate that it is easy to distinguish the three targets by comparing their OCS curves. This work is helpful for the identification and classification of unresolved space target based on photometric characteristics.
Total reaction cross sections in CEM and MCNP6 at intermediate energies
Kerby, Leslie M.; Mashnik, Stepan G.
2015-08-01
Accurate total reaction cross section models are important to achieving reliable predictions from spallation and transport codes. The latest version of the Cascade Exciton Model (CEM) as incorporated in the code CEM03.03, and the Monte Carlo N-Particle transport code (MCNP6), both developed at Los Alamos National Laboratory (LANL), each use such cross sections. Having accurate total reaction cross section models in the intermediate energy region (∼ 50 MeV to ∼ 5 GeV) is very important for different applications, including analysis of space environments, use in medical physics, and accelerator design, to name just a few. The current inverse cross sections used in the preequilibrium and evaporation stages of CEM are based on the Dostrovsky et al. model, published in 1959. Better cross section models are available now. Implementing better cross section models in CEM and MCNP6 should yield improved predictions for particle spectra and total production cross sections, among other results. Our current results indicate this is, in fact, the case.
Total Reaction Cross Sections in CEM and MCNP6 at Intermediate Energies
Kerby, Leslie M
2015-01-01
Accurate total reaction cross section models are important to achieving reliable predictions from spallation and transport codes. The latest version of the Cascade Exciton Model (CEM) as incorporated in the code CEM03.03, and the Monte Carlo N-Particle transport code (MCNP6), both developed at Los Alamos National Laboratory (LANL), each use such cross sections. Having accurate total reaction cross section models in the intermediate energy region ($\\sim$50 MeV to $\\sim$5 GeV) is very important for different applications, including analysis of space environments, use in medical physics, and accelerator design, to name just a few. The current inverse cross sections used in the preequilibrium and evaporation stages of CEM are based on the Dostrovsky {\\it et al.} model, published in 1959. Better cross section models are available now. Implementing better cross section models in CEM and MCNP6 should yield improved predictions for particle spectra and total production cross sections, among other results. Our current...
Institute of Scientific and Technical Information of China (English)
SHI De-Heng; LIU Yu-Fang; SUN Jin-Feng; YANG Xiang-Dong; ZHU Zun-Lue
2005-01-01
@@ The additivity rule model together with the complex optical model potential correlated by the concept of bonded atoms, which considers the overlapping effect of electron clouds between two atoms in a molecule, is firstly employed to calculate the absolute differential cross sections for electrons scattered by carbon monoxide at intermediate and high energies at the Hartree-Fock level. A comparison of elastic differential cross section results, obtained by using the correlated complex optical model potential, with the available experimental data,shows a significant improvement over the uncorrelated ones. The differential cross sections obtained by using the correlated complex optical model potential are in very good agreement with the experimental data. It is shown that the additivity rule model together with the correlated complex optical model potential is suitable for the calculations of the absolute differential cross sections of e-CO scattering.
The thermal neutron scattering cross section of {sup 86}Kr
Energy Technology Data Exchange (ETDEWEB)
Terburg, B.P.
1992-05-01
The availability of 27 1 STP krypton-86 gas, an isotope with unknown thermal neutron scattering cross section, was an excellent occasion to determine the (bound atom) scattering cross section and its coherent part by application of the neutron transmission method and neutron interferometry. The transmission method was applied in a diffractometer, a Larmor spectrometer and a TOF-spectrometer. In addition to {sup 86}Kr also natural krypton ({sup n}Kr) was used for sample in the diffractometer. The diffractometer measurements result in bound atom scattering cross sections {sigma}{sub s}=8.92(46) b for {sup 86}Kr and {sigma}{sub s}=7.08(95) b for {sup n}Kr. The Larmor transmission measurements lead to a final result {sigma}{sub s}=8.44(9) b for {sup 86}Kr. In the TOF-spectrometer the wavelength-dependent total cross section of water was determined. Coherent neutron scattering lengths were determined using the neutron interferometry method with a skew symmetric neutron interferometer. Scans with {sup 86}Kr and {sup n}Kr led to b{sub c}=8.07(26) fm for {sup 86}Kr and 7.72(33) fm for {sup n}Kr, corresponding to coherent scattering cross sections {sigma}{sub c}=8.18(53) b and 7.49(64) b respectively. Due to the large errors in the bound atom scattering cross section and coherent scattering cross section of {sup 86}Kr and {sup n}Kr, the incoherent cross section of both gases, {sigma}{sub i} = 0 within its inaccuracy, {sigma}{sub i}=0.26(54) b for {sup 86}Kr and {sigma}{sub i}=0.41(1.15) b for {sup n}Kr. (orig.).
Single Boson Production Cross Section Measurements in CMS
Lee, Kyeongpil
2017-01-01
Measurements of single boson production cross sections are presented. They are based on proton-proton collision data at 8 and 13 TeV recorded with the CMS detector at the LHC. Inclusive and differential cross sections with respect to various observables are measured in various phase spaces.These measurements are compared to perturbative QCD predictions and generally show good agreement with the prediction.
Partial wave scattering cross sections for He-HBr collision
Institute of Scientific and Technical Information of China (English)
Yu Chun-Ri; Feng Er-Yin; Wang Rong-Kai; Yang Xiang-Dong
2006-01-01
A new anisotropic potential is fitted to ab initio data. The close-coupling approach is utilized to calculate state-to-state rotational excitation partial wave cross sections for elastic and inelastic collisions of He atom with HBr molecule based on the fitted potential. The calculation is performed separately at the incident energies: 75, 100 and 200 meV. The tendency of the elastic and inelastic rotational excitation partial wave cross sections varying with total angular quantum number J is obtained.
Thermal neutron capture cross sections of tellurium isotopes
Tomandl, I.; Honzátko, J.; von Egidy, T.; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklósi, L.; Révay, Zs.; Molnár, G. L.; Firestone, R. B.; Bondarenko, V.
2003-12-01
New values for thermal neutron capture cross sections of the tellurium isotopes 122 Te , 124 Te , 125 Te , 126 Te , 128 Te , and 130 Te are reported. These values are based on a combination of newly determined partial γ -ray cross sections obtained from experiments on targets contained natural Te and γ intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given.
Top Quark Pair Production Cross Section at the Tevatron
Energy Technology Data Exchange (ETDEWEB)
Peters, Reinhild Yvonne [Manchester U.
2015-09-25
The top quark, discovered in 1995 by the CDF and D0 collaborations at the Tevatron proton antiproton collider at Fermilab, has undergone intense studies in the last 20 years. Currently, CDF and D0 converge on their measurements of top-antitop quark production cross sections using the full Tevatron data sample. In these proceedings, the latest results on inclusive and differential measurements of top-antitop quark production cross sections at the Tevatron are reported.
MINERvA - neutrino nucleus cross section experiment
CERN. Geneva
2014-01-01
Recent results from MINERvA, a neutrino cross section experiment at Fermilab, are presented. MINERVA has the goal of providing precision results which will have important impact on oscillation experiments. Initial data runs for muon neutrino and antineutrino beams of ~3.5 GeV have produced a large number of new results. This seminar will introduce the experiment and describe results for quasielastic, pion production, and inclusive cross sections.
Elastic cross sections for electron-carbon scattering
Institute of Scientific and Technical Information of China (English)
Liu Jun-Bo; Wang Yang; Zhou Ya-Jun
2007-01-01
We used the close-coupling optical (CCO) approach to investigate the open-shell carbon atom. The elastic cross sections have been presented at the energies below 90eV, and the present CCO results have been compared with other theoretical results. We found that polarization and the continuum states have significant contributions to the elastic cross sections. The present calculations show that the CCO method is capable of calculating electron scattering from open-shell atoms.
Thermal neutron capture cross sections of tellurium isotopes
Energy Technology Data Exchange (ETDEWEB)
Tomandl, I.; Honzatko, J.; von Egidy, T.; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Zs.; Molnar, G.L.; Firestone, R.B.; Bondarenko, V.
2004-03-01
New values for thermal neutron capture cross sections of the tellurium isotopes 122Te, 124Te, 125Te, 126Te, 128Te, and 130Te are reported. These values are based on a combination of newly determined partial g-ray cross sections obtained from experiments on targets contained natural Te and gamma intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given.
CROSS SECTION EVALUATIONS FOR ENDF/B-VII.
Energy Technology Data Exchange (ETDEWEB)
HERMAN, M.; ROCHMAN, D.; OBLOZINSKY, P.
2006-06-05
This is the final report of the work performed under the LANL contract on neutron cross section evaluations for ENDF/B-VII (April 2005-May 2006). The purpose of the contract was to ensure seamless integration of the LANL neutron cross section evaluations in the new ENDF/B-VII library. The following work was performed: (1) LANL evaluated data files submitted for inclusion in ENDF/B-VII were checked and, when necessary, formal formatting errors were corrected. As a consequence, ENDF checking codes, run on all LANL files, do not report any errors that would rise concern. (2) LANL dosimetry evaluations for {sup 191}Ir and {sup 193}Ir were completed to match ENDF requirements for the general purpose library suitable for transport calculations. A set of covariances for both isotopes is included in the ENDF files. (3) Library of fission products was assembled and successfully tested with ENDF checking codes, processed with NJOY-99.125 and simple MCNP calculations. (4) KALMAN code has been integrated with the EMPIRE system to allow estimation of covariances based on the combination of measurements and model calculations. Covariances were produced for 155,157-Gd and also for 6 remaining isotopes of Gd.
WW cross section and branching fraction measurements at LEP
Malgeri, L
1999-01-01
In two years of running at energies above WW production threshold, LEP-II provided each experiment an integrated luminosity of ~80 pb /sup -1/ until the end of 1997. The amount of collected events, ~1000 /experiment, allows to measure with high precision the total e/sup + /e/sup -/ to WW cross section: sigma /sub WW/( square root s=182.7 Ge V)=15.89+or-0.40 pb and the W-boson decay branching fractions: BR(W to qq)=68.79+or-0.77% and BR(W to l nu /sub l/)=10.40+or-0.26%, both in good agreement with Standard Model expectations. The W decay branching fractions and the total WW cross section are also used to extract a value for the Cabibbo-Kobayashi-Mas kawa matrix element V /sub cs/ and to put stringent limits on the invisible W width, Gamma /sub W//sup in upsilon /. A preliminary and incomplete look at the first data of this year, which is foreseen to increase the available statistics by four times, is also herein presented. (14 refs).
Variation of photoabsorption cross section of atomic silver from isolated to condensed conditions*
Institute of Scientific and Technical Information of China (English)
Ma Xiao-Guang; Gong Yu-Bing; Qu Zhao-Jun
2009-01-01
The influence of the local-field on the photoabsorption cross section of the atomic silver is studied in detail by using the Clausius-Mossotti(CM)model and the Onsager model separately.The variations of the photoabsorption cross section of atomic silver with number density and radius of the environmental interaction cavity are studied systematically by using more general expressions for the photoabsorption cross sections,proposed by Sun et al recently.It has proved to be reasonable to model the optical response properties of bulky material by coupling the property of isolated atom with the environmental effccts in the present work.
Total Cross Sections and Event Properties from Real to Virtual Photons
Friberg, C; Friberg, Christer; Sjöstrand, Torbjörn
2000-01-01
A model for total cross sections with virtual photons is presented. In particular gamma*-p and gamma*-gamma* cross sections are considered. Our approach extends on a model for photoproduction, where the total cross section is subdivided into three distinct event classes: direct, VMD and anomalous. With increasing photon virtuality, the latter two decrease in importance. Instead Deep Inelastic Scattering dominates, with the direct class being the O(alpha_s) correction thereof. Hence, the model provides a smooth transition between the two regions. By the breakdown into different event classes, one may aim for a complete picture of all event properties.
Total Cross Sections and Event Properties from Real to Virtual Photons
Friberg, Christer; 10.1088/1126-6708/2000/09/010
2009-01-01
A model for total cross sections with virtual photons is presented. In particular gamma*-p and gamma*-gamma* cross sections are considered. Our approach extends on a model for photoproduction, where the total cross section is subdivided into three distinct event classes: direct, VMD and anomalous. With increasing photon virtuality, the latter two decrease in importance. Instead Deep Inelastic Scattering dominates, with the direct class being the O(alpha_s) correction thereof. Hence, the model provides a smooth transition between the two regions. By the breakdown into different event classes, one may aim for a complete picture of all event properties.
Modeling golden section in plants
Institute of Scientific and Technical Information of China (English)
Lanling Zeng; Guozhao Wang
2009-01-01
Plants are complex structures, changing their shapes in response to environmental factors such as sunlight, water and neighboring plants. However, some mathematical rules can be found in their growth patterns, one of which is the golden section. The golden section can be observed in branching systems, phyllotaxis, flowers and seeds, and often the spiral arrangement of plant organs. In this study, tree, flower and fruit models have been generated by using the corresponding golden section characteristics, resulting in more natural patterns. Furthermore, the golden section can be found in the bifurcate angles of trees and lobed leaves, extending the golden section theory.
Photodissociation cross section of ClOOCl at 330 nm.
Jin, Bing; Chen, I-Cheng; Huang, Wen-Tsung; Lien, Chien-Yu; Guchhait, Nikhil; Lin, Jim J
2010-04-15
The photolysis rate of ClOOCl is crucial in the catalytic destruction of polar stratospheric ozone. In this work, we determined the photodissociation cross section of ClOOCl at 330 nm with a molecular beam and with mass-resolved detection. The photodissociation cross section is the product of the absorption cross section and the dissociation quantum yield. We formed an effusive molecular beam of ClOOCl at a nozzle temperature of 200 or 250 K and determined its photodissociation probability by measuring the decrease of the ClOOCl intensity upon laser irradiation. By comparing with a reference molecule (Cl(2)), of which the absorption cross section and dissociation quantum yield are well-known, we determined the absolute photodissociation cross section of ClOOCl at 330 nm to be (2.31 +/- 0.11) x 10(-19) cm(2) at 200 K and (2.47 +/- 0.12) x 10(-19) cm(2) at 250 K. Impurity interference has been a well-recognized problem in conventional spectroscopic studies of ClOOCl; our mass-resolved measurement directly overcomes such a problem. This measurement of the ClOOCl photolysis cross section at 330 nm is particularly useful in constraining its atmospheric photolysis rate, which in the polar stratosphere peaks near this wavelength.
Status of the Neutron Cross-Section Standards Database
Hambsch, Franz-Josef; Carlson, Allan D.; Vonach, Herbert
2005-05-01
A new evaluation of the neutron cross-section standards is now underway. This evaluation has been supported by the Working Party on International Evaluation Cooperation (WPEC), the Cross Section Evaluation Working Group (CSEWG), and an International Atomic Energy Agency Coordinated Research Program (CRP). The CRP has had the dominant role in producing these evaluations. An important goal is to produce the standards needed for the upcoming new ENDF/B-VII library. Since most neutron cross-section measurements are made relative to neutron cross-section standards, the standards evaluation is of crucial importance. The standard reactions to be evaluated are: H(n,n), 3He(n,p), 6Li(n,t), 10B(n,α), 10B(n,α1γ), C(n,n), Au(n,γ), 235U(n,f), and 238U(n,f). These standards should receive international acceptance to ensure that all evaluation projects use the same set of standards. The last complete evaluation of the standards dates back almost 20 years. In the meantime quite a number of new and improved measurements have occurred for the cross-section standards. International efforts are presently underway to update the experimental database and to improve the evaluation process. Due to the need for high-energy standards, the energy range is being extended to 200 MeV for some of the cross-section standards.
Methodology Series Module 3: Cross-sectional Studies.
Setia, Maninder Singh
2016-01-01
Cross-sectional study design is a type of observational study design. In a cross-sectional study, the investigator measures the outcome and the exposures in the study participants at the same time. Unlike in case-control studies (participants selected based on the outcome status) or cohort studies (participants selected based on the exposure status), the participants in a cross-sectional study are just selected based on the inclusion and exclusion criteria set for the study. Once the participants have been selected for the study, the investigator follows the study to assess the exposure and the outcomes. Cross-sectional designs are used for population-based surveys and to assess the prevalence of diseases in clinic-based samples. These studies can usually be conducted relatively faster and are inexpensive. They may be conducted either before planning a cohort study or a baseline in a cohort study. These types of designs will give us information about the prevalence of outcomes or exposures; this information will be useful for designing the cohort study. However, since this is a 1-time measurement of exposure and outcome, it is difficult to derive causal relationships from cross-sectional analysis. We can estimate the prevalence of disease in cross-sectional studies. Furthermore, we will also be able to estimate the odds ratios to study the association between exposure and the outcomes in this design.
Borisov, A. V.; Kuznetsov, S. P.; Mamaev, I. S.; Tenenev, V. A.
2016-09-01
From analysis of time series obtained on the numerical solution of a plane problem on the motion of a body with an elliptic cross section under the action of gravity force in an incompressible viscous fluid, a system of ordinary differential equations approximately describing the dynamics of the body is reconstructed. To this end, coefficients responsible for the added mass, the force caused by the circulation of the velocity field, and the resisting force are found by the least square adjustment. The agreement between the finitedimensional description and the simulation on the basis of the Navier-Stokes equations is illustrated by images of attractors in regular and chaotic modes. The coefficients found make it possible to estimate the actual contribution of different effects to the dynamics of the body.