The multistate impact parameter method for molecular charge exchange in nitrogen

NASA Technical Reports Server (NTRS)

Ioup, J. W.

1980-01-01

The multistate impact parameter method is applied to the calculation of total cross sections for low energy change transfer between nitrogen ions and nitrogen molecules. Experimental data showing the relationships between total cross section and ion energy for various pressures and electron ionization energies were obtained. Calculated and experimental cross section values from the work are compared with the experimental and theoretical results of other investigators.

Electron impact ionization in plasma technologies; studies on atomic boron and BN molecule

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, Foram M., E-mail: foram29@gmail.com; Joshipura, K. N., E-mail: knjoshipura22@gmail.com; Chaudhari, Asha S., E-mail: ashaschaudhari@gmail.com

2016-05-06

Electron impact ionization plays important role in plasma technologies. Relevant cross sections on atomic boron are required to understand the erosion processes in fusion experiments. Boronization of plasma exposed surfaces of tokomaks has proved to be an effective way to produce very pure fusion plasmas. This paper reports comprehensive theoretical investigations on electron scattering with atomic Boron and Boron Nitride in solid phases. Presently we determine total ionization cross-section Q{sub ion} and the summed-electronic excitation cross section ΣQ{sub exc} in a standard quantum mechanical formalism called SCOP and CSP-ic methods. Our calculated cross sections are examined as functions of incidentmore » electron energy along with available comparisons.« less

Application of relativistic coupled-cluster theory to electron impact excitation of Mg+ in the plasma environment

NASA Astrophysics Data System (ADS)

Sharma, Lalita; Sahoo, Bijaya Kumar; Malkar, Pooja; Srivastava, Rajesh

2018-01-01

A relativistic coupled-cluster theory is implemented to study electron impact excitations of atomic species. As a test case, the electron impact excitations of the 3 s 2 S 1/2-3 p 2 P 1/2;3/2 resonance transitions are investigated in the singly charged magnesium (Mg+) ion using this theory. Accuracies of wave functions of Mg+ are justified by evaluating its attachment energies of the relevant states and compared with the experimental values. The continuum wave function of the projectile electron are obtained by solving Dirac equations assuming distortion potential as static potential of the ground state of Mg+. Comparison of the calculated electron impact excitation differential and total cross-sections with the available measurements are found to be in very good agreements at various incident electron energies. Further, calculations are carried out in the plasma environment in the Debye-Hückel model framework, which could be useful in the astrophysics. Influence of plasma strength on the cross-sections as well as linear polarization of the photon emission in the 3 p 2 P 3/2-3 s 2 S 1/2 transition is investigated for different incident electron energies.

Electron impact scattering study of hypohalous acids HOX (X = F, Cl, Br, I)

NASA Astrophysics Data System (ADS)

Yadav, Hitesh; Bhutadia, Harshad; Prajapati, Dinesh; Desai, Hardik; Vinodkumar, Minaxi; Vinodkumar, P. C.

2018-05-01

In this article we aim to report total cross sections (TCS) QT, total elastic cross sections (Qel), total inelastic cross sections (Qinel) i.e. (total ionizations cross sections (Qion)+total electronic excitation cross sections (Qexc)) from threshold of the target to 5000 eV energy range. We have used a well-defined theoretical methodology Spherical Complex Optical Potential (SCOP) to compute QT, Qel and Qinel and Complex Scattering Potential - ionization contribution (CSP - ic) method to report the (Qion). The cross-sectional data reported here for the Hypohalous Acids is for the first time and the present data can become a guideline for the experimentalist to study these targets.

Comparison of local exchange potentials of electron-N2 scattering

NASA Astrophysics Data System (ADS)

Rumble, J. R., Jr.; Truhlar, D. G.

1980-05-01

Vibrationally and electronically elastic electron scattering by N2 at 2-30 eV impact energy is considered. Static, static-exchange, and static-exchange-plus-polarization potentials, Cade-Sales-Wahl and INDO/1s wave functions, and semiclassical exchange and Hara free-electron-gas exchange potentials are examined. It is shown that the semiclassical exchange approximation is too attractive at low energy for N2. It is also shown quantitatively by consideration of partial and total integral cross sections how the effects of approximations to exchange become smaller as the incident energy is increased until the differences are about 8% for the total integral cross section at 30 eV.

Electron-impact total ionization cross sections of DNA sugar-phosphate backbone and an additivity principle

NASA Technical Reports Server (NTRS)

Huo, Winifred M.; Dateo, Christopher E.

2005-01-01

The improved binary-encounter dipole (iBED) model [W.M. Huo, Phys. Rev. A64, 042719-1 (2001)l is used to study the total ionization cross sections of the DNA sugar-phosphate backbone by electron impact. Calculations using neutral fragments found that the total ionization cross sections of C3' - and C5', -deoxyribose-phospate, 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 C3' - and C5" -deoxyribose-phospate cross sections, differing by less than 10%. The result implies that certain properties of the-DNA, like the total singly ionization cross section, are localized properties and a building-up or additivity principle may apply. This allows us to obtain accurate properties of larger molecular systems built up from the results of smaller subsystem fragments. Calculations are underway using a negatively charged sugar-phosphate backbone with a metal counter-ion.

Absolute total and partial dissociative cross sections of pyrimidine at electron and proton intermediate impact velocities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolff, Wania, E-mail: wania@if.ufrj.br; Luna, Hugo; Sigaud, Lucas

Absolute total non-dissociative and partial dissociative cross sections of pyrimidine were measured for electron impact energies ranging from 70 to 400 eV and for proton impact energies from 125 up to 2500 keV. MOs ionization induced by coulomb interaction were studied by measuring both ionization and partial dissociative cross sections through time of flight mass spectrometry and by obtaining the branching ratios for fragment formation via a model calculation based on the Born approximation. The partial yields and the absolute cross sections measured as a function of the energy combined with the model calculation proved to be a useful toolmore » to determine the vacancy population of the valence MOs from which several sets of fragment ions are produced. It was also a key point to distinguish the dissociation regimes induced by both particles. A comparison with previous experimental results is also presented.« less

Quantifying Energetic Electron Precipitation And Its Effect on Atmospheric Chemistry

NASA Astrophysics Data System (ADS)

Huang, C. L.; Spence, H. E.; Smith, S. S.; Duderstadt, K. A.; Boyd, A. J.; Geoffrey, R.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.; Turner, D. L.; Crew, A. B.; Klumpar, D. M.; Shumko, M.; Johnson, A.; Sample, J. G.

2017-12-01

In this study we quantify the total radiation belt electron loss through precipitation into the atmosphere, and simulate the electrons' contribution to changing the atmospheric composition. We use total radiation belt electron content (TRBEC) calculated from Van Allen Probes ECT/MagEIS data to estimate the precipitation during electron loss events. The new TRBEC index is a high-level quantity for monitoring the entire radiation belt and has the benefit of removing both internal transport and the adiabatic effect. To assess the electron precipitation rate, we select TRBEC loss events that show no outward transport in the phase space density data in order to exclude drift magnetopause loss. Then we use FIREBIRD data to estimate and constrain the precipitation loss when it samples near the loss cone. Finally, we estimate the impact of electron precipitation on the composition of the upper and middle atmosphere using global climate simulations.

A Numerical Model of Laser-Induced Fluorescence in a Hydrogen Plasma

DTIC Science & Technology

1991-03-10

cross-sections. Lee, et al., cited screened Coulomb potential calculations by several groups to place an up- per limit of 30 A on the Debye length...intensity: RL(t)(1/sec) = B,,(cir 2/erg . sec) . (J,)(erg/sec .cm -. liz) (3.5) 35 The Einstein coefficients are related by the statistical weights of the...impact processes.) These rate matrices were then added together to obtain the total rate matrix for both groups of electrons. The total electron density

Simple and universal model for electron-impact ionization of complex biomolecules

NASA Astrophysics Data System (ADS)

Tan, Hong Qi; Mi, Zhaohong; Bettiol, Andrew A.

2018-03-01

We present a simple and universal approach to calculate the total ionization cross section (TICS) for electron impact ionization in DNA bases and other biomaterials in the condensed phase. Evaluating the electron impact TICS plays a vital role in ion-beam radiobiology simulation at the cellular level, as secondary electrons are the main cause of DNA damage in particle cancer therapy. Our method is based on extending the dielectric formalism. The calculated results agree well with experimental data and show a good comparison with other theoretical calculations. This method only requires information of the chemical composition and density and an estimate of the mean binding energy to produce reasonably accurate TICS of complex biomolecules. Because of its simplicity and great predictive effectiveness, this method could be helpful in situations where the experimental TICS data are absent or scarce, such as in particle cancer therapy.

Dissociation of CH4 by electron impact: Production of metastable hydrogen and carbon fragments

NASA Technical Reports Server (NTRS)

Finn, T. G.; Carnahan, B. L.; Zipf, E. C.

1974-01-01

Metastable fragments produced by electron impact excitation of CH4 have been investigated for incident electron energies from threshold to 300 eV. Only metastable hydrogen and carbon atoms were observed. Onset energies for the production of metastable hydrogen atoms were observed at electron impact energies of 22.0 + or - .5 eV, 25.5 + or - .6 eV, 36.7 + or - .6 eV and 66 + or - 3 eV, and at 26.6 + or - .6 eV for the production of metastable carbon atoms. Most of the fragments appear to have been formed in high-lying Rydberg states. The total metastable hydrogen cross section reaches a maximum value of approximately 1 X 10 to the minus 18th power sq cm at 100 eV. At the same energy, the metastable carbon cross section is 2 x 10 to the minus 19th power sq cm.

Measurement of inelastic cross sections for low-energy electron scattering from DNA bases.

PubMed

Michaud, Marc; Bazin, Marc; Sanche, Léon

2012-01-01

To determine experimentally the absolute cross sections (CS) to deposit various amount of energies into DNA bases by low-energy electron (LEE) impact. Electron energy loss (EEL) spectra of DNA bases were recorded for different LEE impact energies on the molecules deposited at very low coverage on an inert argon (Ar) substrate. Following their normalisation to the effective incident electron current and molecular surface number density, the EEL spectra were then fitted with multiple Gaussian functions in order to delimit the various excitation energy regions. The CS to excite a molecule into its various excitation modes were finally obtained from computing the area under the corresponding Gaussians. The EEL spectra and absolute CS for the electronic excitations of pyrimidine and the DNA bases thymine, adenine, and cytosine by electron impacts below 18 eV were reported for the molecules deposited at about monolayer coverage on a solid Ar substrate. The CS for electronic excitations of DNA bases by LEE impact were found to lie within the 10(216) to 10(218) cm(2) range. The large value of the total ionisation CS indicated that ionisation of DNA bases by LEE is an important dissipative process via which ionising radiation degrades and is absorbed in DNA.

Measurement of inelastic cross sections for low-energy electron scattering from DNA bases

PubMed Central

Michaud, Marc; Bazin, Marc.; Sanche, Léon

2013-01-01

Purpose Determine experimentally the absolute cross sections (CS) to deposit various amount of energies into DNA bases by low-energy electron (LEE) impact. Materials and methods Electron energy loss (EEL) spectra of DNA bases are recorded for different LEE impact energies on the molecules deposited at very low coverage on an inert argon (Ar) substrate. Following their normalisation to the effective incident electron current and molecular surface number density, the EEL spectra are then fitted with multiple Gaussian functions in order to delimit the various excitation energy regions. The CS to excite a molecule into its various excitation modes are finally obtained from computing the area under the corresponding Gaussians. Results The EEL spectra and absolute CS for the electronic excitations of pyrimidine and the DNA bases thymine, adenine, and cytosine by electron impacts below 18 eV are reported for the molecules deposited at about monolayer coverage on a solid Ar substrate. Conclusions The CS for electronic excitations of DNA bases by LEE impact are found to lie within the 10−16 – 10−18 cm2 range. The large value of the total ionisation CS indicates that ionisation of DNA bases by LEE is an important dissipative process via which ionising radiation degrades and is absorbed in DNA. PMID:21615242

Image charge effects on electron capture by dust grains in dusty plasmas.

PubMed

Jung, Y D; Tawara, H

2001-07-01

Electron-capture processes by negatively charged dust grains from hydrogenic ions in dusty plasmas are investigated in accordance with the classical Bohr-Lindhard model. The attractive interaction between the electron in a hydrogenic ion and its own image charge inside the dust grain is included to obtain the total interaction energy between the electron and the dust grain. The electron-capture radius is determined by the total interaction energy and the kinetic energy of the released electron in the frame of the projectile dust grain. The classical straight-line trajectory approximation is applied to the motion of the ion in order to visualize the electron-capture cross section as a function of the impact parameter, kinetic energy of the projectile ion, and dust charge. It is found that the image charge inside the dust grain plays a significant role in the electron-capture process near the surface of the dust grain. The electron-capture cross section is found to be quite sensitive to the collision energy and dust charge.

Electron-impact vibrational relaxation in high-temperature nitrogen

NASA Technical Reports Server (NTRS)

Lee, Jong-Hun

1992-01-01

Vibrational relaxation process of N2 molecules by electron-impact is examined for the future planetary entry environments. Multiple-quantum transitions from excited states to higher/lower states are considered for the electronic ground state of the nitrogen molecule N2 (X 1Sigma-g(+)). Vibrational excitation and deexcitation rate coefficients obtained by computational quantum chemistry are incorporated into the 'diffusion model' to evaluate the time variations of vibrational number densities of each energy state and total vibrational energy. Results show a non-Boltzmann distribution of number densities at the earlier stage of relaxation, which in turn suppresses the equilibrium process but affects little the time variation of total vibrational energy. An approximate rate equation and a corresponding relaxation time from the excited states, compatible with the system of flow conservation equations, are derived. The relaxation time from the excited states indicates the weak dependency of the initial vibrational temperature. The empirical curve-fit formula for the improved e-V relaxation time is obtained.

Suppression of the Polar Tongue of Ionization During the 21 August 2017 Solar Eclipse

NASA Astrophysics Data System (ADS)

Dang, Tong; Lei, Jiuhou; Wang, Wenbin; Burns, Alan; Zhang, Binzheng; Zhang, Shun-Rong

2018-04-01

It has long been recognized that during solar eclipses, the ionosphere-thermosphere system changes greatly within the eclipse shadow, due to the rapid reduction of solar irradiation. However, the concept that a solar eclipse impacts polar ionosphere behavior and dynamics as well as magnetosphere-ionosphere coupling has not been appreciated. In this study, we investigate the potential impact of the 21 August 2017 solar eclipse on the polar tongue of ionization (TOI) using a high-resolution, coupled ionosphere-thermosphere-electrodynamics model. The reduction of electron densities by the eclipse in the middle latitude TOI source region leads to a suppressed TOI in the polar region. The TOI suppression occurred when the solar eclipse moved into the afternoon sector. The Global Positioning System total electron content observations show similar tendency of polar region total electron content suppression. This study reveals that a solar eclipse occurring at middle latitudes may have significant influences on the polar ionosphere and magnetosphere-ionosphere coupling.

Brightness measurement of an electron impact gas ion source for proton beam writing applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, N.; Santhana Raman, P.; Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583

We are developing a high brightness nano-aperture electron impact gas ion source, which can create ion beams from a miniature ionization chamber with relatively small virtual source sizes, typically around 100 nm. A prototype source of this kind was designed and successively micro-fabricated using integrated circuit technology. Experiments to measure source brightness were performed inside a field emission scanning electron microscope. The total output current was measured to be between 200 and 300 pA. The highest estimated reduced brightness was found to be comparable to the injecting focused electron beam reduced brightness. This translates into an ion reduced brightness thatmore » is significantly better than that of conventional radio frequency ion sources, currently used in single-ended MeV accelerators.« less

Brightness measurement of an electron impact gas ion source for proton beam writing applications.

PubMed

Liu, N; Xu, X; Pang, R; Raman, P Santhana; Khursheed, A; van Kan, J A

2016-02-01

We are developing a high brightness nano-aperture electron impact gas ion source, which can create ion beams from a miniature ionization chamber with relatively small virtual source sizes, typically around 100 nm. A prototype source of this kind was designed and successively micro-fabricated using integrated circuit technology. Experiments to measure source brightness were performed inside a field emission scanning electron microscope. The total output current was measured to be between 200 and 300 pA. The highest estimated reduced brightness was found to be comparable to the injecting focused electron beam reduced brightness. This translates into an ion reduced brightness that is significantly better than that of conventional radio frequency ion sources, currently used in single-ended MeV accelerators.

Electron impact ionization of cycloalkanes, aldehydes, and ketones

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Dhanoj; Antony, Bobby, E-mail: bka.ism@gmail.com

The theoretical calculations of electron impact total ionization cross section for cycloalkane, aldehyde, and ketone group molecules are undertaken from ionization threshold to 2 keV. The present calculations are based on the spherical complex optical potential formalism and complex scattering potential ionization contribution method. The results of most of the targets studied compare fairly well with the recent measurements, wherever available and the cross sections for many targets are predicted for the first time. The correlation between the peak of ionization cross sections with number of target electrons and target parameters is also reported. It was found that the crossmore » sections at their maximum depend linearly with the number of target electrons and with other target parameters, confirming the consistency of the values reported here.« less

Electron impact ionisation cross section for organoplatinum compounds

NASA Astrophysics Data System (ADS)

Mahato, Dibyendu; Naghma, Rahla; Alam, Mohammad Jane; Ahmad, Shabbir; Antony, Bobby

2016-11-01

This article reports electron impact ionisation cross sections for platinum-based drugs viz., cisplatin (H6N2Cl2Pt), carboplatin (C6H12N2O4Pt), oxaliplatin (C8H14N2O4Pt), nedaplatin (C2H8N2O3Pt) and satraplatin (C10H22ClN2O4Pt) complexes used in the cancer chemotherapy. The multi-scattering centre spherical complex optical potential formalism is used to obtain the inelastic cross section for these large molecules upon electron impact. The ionisation cross section is derived from the inelastic cross section employing complex scattering potential-ionisation contribution method. Comparison is made with previous results, where ever available and overall a reasonable agreement is observed. This is the first attempt to report total ionisation cross sections for nedaplatin and satraplatin complexes.

Total electron scattering cross section from pyridine molecules in the energy range 10-1000 eV

NASA Astrophysics Data System (ADS)

Dubuis, A. Traoré; Costa, F.; da Silva, F. Ferreira; Limão-Vieira, P.; Oller, J. C.; Blanco, F.; García, G.

2018-05-01

We report on experimental total electron scattering cross-section (TCS) from pyridine (C5H5N) for incident electron energies between 10 and 1000 eV, with experimental uncertainties within 5-10%, as measured with a double electrostatic analyser apparatus. The experimental results are compared with our theoretical calculations performed within the independent atom model complemented with a screening corrected additivity rule (IAM-SCAR) procedure which has been updated by including interference effects. A good level of agreement is found between both data sources within the experimental uncertainties. The present TCS results for electron impact energy under study contribute, together with other scattering data available in the literature, to achieve a consistent set of cross section data for modelling purposes.

Tutorial: Radiation Effects in Electronic Systems

NASA Technical Reports Server (NTRS)

Pellish, Jonathan A.

2017-01-01

This tutorial presentation will give an overview of radiation effects in electrical, electronic, and electromechanical (EEE) components as it applies to civilian space systems of varying size and complexity. The natural space environment presents many unique threats to electronic systems regardless of where the systems operate from low-Earth orbit to interplanetary space. The presentation will cover several topics, including: an overview and introduction to the applicable space radiation environments common to a broad range of mission designs; definitions and impacts of effects due to impinging particles in the space environment e.g., total ionizing dose (TID), total non-ionizing dose (TNID), and single-event effects (SEE); and, testing for and evaluation of TID, TNID, and SEE in EEE components.

Modeling of the Ionospheric Scintillation and Total Electron Content Observations during the 21 August 2017 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Datta-Barua, S.; Gachancipa, J. N.; Deshpande, K.; Herrera, J. A.; Lehmacher, G. A.; Su, Y.; Gyuk, G.; Bust, G. S.; Hampton, D. L.

2017-12-01

High concentration of free electrons in the ionosphere can cause fluctuations in incoming electromagnetic waves, such as those from the different Global Navigation Satellite Systems (GNSS). The behavior of the ionosphere depends on time and location, and it is highly influenced by solar activity. The purpose of this study is to determine the impact of a total solar eclipse on the local ionosphere in terms of ionospheric scintillations, and on the global ionosphere in terms of TEC (Total Electron Content). The studied eclipse occurred on 21 August 2017 across the continental United States. During the eclipse, we expected to see a decrease in the scintillation strength, as well as in the TEC values. As a broader impact part of our recently funded NSF proposal, we temporarily deployed two GNSS receivers on the eclipse's totality path. One GNSS receiver was placed in Clemson, SC. This is a multi-frequency GNSS receiver (NovAtel GPStation-6) capable of measuring high and low rate scintillation data as well as TEC values from four different GNSS systems. We had the receiver operating before, during, and after the solar eclipse to enable the comparison between eclipse and non-eclipse periods. A twin receiver collected data at Daytona Beach, FL during the same time, where an 85% partial solar eclipse was observed. Additionally, we set up a ground receiver onsite in the path of totality in Perryville, Missouri, from which the Adler Planetarium of Chicago launched a high-altitude balloon to capture a 360-degree video of the eclipse from the stratosphere. By analyzing the collected data, this study looks at the effects of partial and total solar eclipse periods on high rate GNSS scintillation data at mid-latitudes, which had not been explored in detail. This study also explores the impact of solar eclipses on signals from different satellite constellations (GPS, GLONASS, and Galileo). Throughout the eclipse, the scintillation values did not appear to have dramatic changes. However, we observed lower scintillation activity on several satellites from different constellations. For example, between 16 UTC and 22 UTC, there was a slight drop in the S4 scintillation Index (amplitude) values, reaching a local minimum during the time of eclipse totality ( 18:30 UTC). Regarding the Total Electron Content (TEC), which measures the quantity of electrons in the ionosphere, there was a more drastic decrease in the values throughout the partial and total solar eclipse. Additionally, σφ (sigma-phi) values for phase scintillation showed the similar behavior compared to previous few days. This reveals that the solar eclipse did not have a major effect on the phase scintillation. In any case, the totality path was entirely in mid-latitude regions, where phase scintillations are expected to be lower compared to high latitudes.

77 FR 54610 - Agency Information Collection Activities: Proposed Collection; Comments Requested: Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-05

... of appropriate automated, electronic, mechanical, or other technological collection techniques or... adverse impact on the environment. (5) An estimate of the total number of respondents and the amount of...

Utilisation and Impact of the Essential Electronic Agricultural Database (TEEAL) on Library Services in a Nigerian University of Agriculture

ERIC Educational Resources Information Center

Oduwole, A. A.; Sowole, A. O.

2006-01-01

Purpose: This study examined the utilisation of the Essential Electronic Agricultural Library database (TEEAL) at the University of Agriculture Library, Abeokuta, Nigeria. Design/methodology/approach: Data collection was by questionnaire following a purposive sampling technique. A total of 104 out 150 (69.3 per cent) responses were received and…

Energy and angular distribution of electrons ejected from water by the impact of fast O8+ ion beams

NASA Astrophysics Data System (ADS)

Bhattacharjee, Shamik; Bagdia, Chandan; Chowdhury, Madhusree Roy; Monti, Juan M.; Rivarola, Roberto D.; Tribedi, Lokesh C.

2018-01-01

Double differential cross sections (DDCS) of electrons emitted from vapor water molecules (in vapor phase) by 2.0 MeV/u and 3.75 MeV/u bare oxygen ion impact have been measured by continuum electron spectroscopy technique. The ejected electrons were detected by an electrostatic hemispherical deflection analyzer over an energy range of 1-600 eV and emission angles from 20∘ to 160∘. The DDCS data has been compared with the continuum-distorted-wave-eikonal-initial state (CDW-EIS) approximation and a reasonable agreement was found with both version of the models i.e. post and prior version. By numerical integration of the DDCS data, the single differential cross section (SDCS) and total ionization cross section (TCS) were obtained. The obtained TCS results were compared with other available TCS results for water target within the same energy range. The total ionization cross sections values are seen to saturate as the projectile charge state ( q p ) increases, which is in contrast to the first-Born predicted q p 2 dependence. This is also in contrast to the prediction of the CDW-EIS models.

Indirect contributions to electron-impact ionization of Li+ (1 s 2 s S31 ) ions: Role of intermediate double-K -vacancy states

NASA Astrophysics Data System (ADS)

Müller, A.; Borovik, A.; Huber, K.; Schippers, S.; Fursa, D. V.; Bray, I.

2018-02-01

Fine details of the cross section for electron-impact ionization of metastable two-electron Li+(1 s 2 s S31) ions are scrutinized by both experiment and theory. Beyond direct knockoff ionization, indirect ionization mechanisms proceeding via formation of intermediate double-K-vacancy (hollow) states either in a Li+ ion or in a neutral lithium atom and subsequent emission of one or two electrons, respectively, can contribute to the net production of Li2 + ions. The partial cross sections for such contributions are less than 4% of the total single-ionization cross section. The characteristic steps, resonances, and interference phenomena in the indirect ionization contribution are measured with an experimental energy spread of less than 0.9 eV and with a statistical relative uncertainty of the order of 1.7%, requiring a level of statistical uncertainty in the total single-ionization cross section of better than 0.05%. The measurements are accompanied by convergent-close-coupling calculations performed on a fine energy grid. Theory and experiment are in remarkable agreement concerning the fine details of the ionization cross section. Comparison with previous R-matrix results is less favorable.

Intermediate energy cross sections for electron-impact vibrational-excitation of pyrimidine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, D. B.; Ellis-Gibbings, L.; García, G.

2015-09-07

We report differential cross sections (DCSs) and integral cross sections (ICSs) for electron-impact vibrational-excitation of pyrimidine, at incident electron energies in the range 15–50 eV. The scattered electron angular range for the DCS measurements was 15°–90°. The measurements at the DCS-level are the first to be reported for vibrational-excitation in pyrimidine via electron impact, while for the ICS we extend the results from the only previous condensed-phase study [P. L. Levesque, M. Michaud, and L. Sanche, J. Chem. Phys. 122, 094701 (2005)], for electron energies ⩽12 eV, to higher energies. Interestingly, the trend in the magnitude of the lower energymore » condensed-phase ICSs is much smaller when compared to the corresponding gas phase results. As there is no evidence for the existence of any shape-resonances, in the available pyrimidine total cross sections [Baek et al., Phys. Rev. A 88, 032702 (2013); Fuss et al., ibid. 88, 042702 (2013)], between 10 and 20 eV, this mismatch in absolute magnitude between the condensed-phase and gas-phase ICSs might be indicative for collective-behaviour effects in the condensed-phase results.« less

Comparison of the secondary electrons produced by proton and electron beams in water

NASA Astrophysics Data System (ADS)

Kia, Mohammad Reza; Noshad, Houshyar

2016-05-01

The secondary electrons produced in water by electron and proton beams are compared with each other. The total ionization cross section (TICS) for an electron impact in water is obtained by using the binary-encounter-Bethe model. Hence, an empirical equation based on two adjustable fitting parameters is presented to determine the TICS for proton impact in media. In order to calculate the projectile trajectory, a set of stochastic differential equations based on the inelastic collision, elastic scattering, and bremsstrahlung emission are used. In accordance with the projectile trajectory, the depth dose deposition, electron energy loss distribution in a certain depth, and secondary electrons produced in water are calculated. The obtained results for the depth dose deposition and energy loss distribution in certain depth for electron and proton beams with various incident energies in media are in excellent agreement with the reported experimental data. The difference between the profiles for the depth dose deposition and production of secondary electrons for a proton beam can be ignored approximately. But, these profiles for an electron beam are completely different due to the effect of elastic scattering on electron trajectory.

Comparison of the secondary electrons produced by proton and electron beams in water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kia, Mohammad Reza, E-mail: m-r-kia@aut.ac.ir; Noshad, Houshyar

The secondary electrons produced in water by electron and proton beams are compared with each other. The total ionization cross section (TICS) for an electron impact in water is obtained by using the binary-encounter-Bethe model. Hence, an empirical equation based on two adjustable fitting parameters is presented to determine the TICS for proton impact in media. In order to calculate the projectile trajectory, a set of stochastic differential equations based on the inelastic collision, elastic scattering, and bremsstrahlung emission are used. In accordance with the projectile trajectory, the depth dose deposition, electron energy loss distribution in a certain depth, andmore » secondary electrons produced in water are calculated. The obtained results for the depth dose deposition and energy loss distribution in certain depth for electron and proton beams with various incident energies in media are in excellent agreement with the reported experimental data. The difference between the profiles for the depth dose deposition and production of secondary electrons for a proton beam can be ignored approximately. But, these profiles for an electron beam are completely different due to the effect of elastic scattering on electron trajectory.« less

Relativistic inverse Compton scattering of photons from the early universe.

PubMed

Malu, Siddharth; Datta, Abhirup; Colafrancesco, Sergio; Marchegiani, Paolo; Subrahmanyan, Ravi; Narasimha, D; Wieringa, Mark H

2017-12-05

Electrons at relativistic speeds, diffusing in magnetic fields, cause copious emission at radio frequencies in both clusters of galaxies and radio galaxies through non-thermal radiation emission called synchrotron. However, the total power radiated through this mechanism is ill constrained, as the lower limit of the electron energy distribution, or low-energy cutoffs, for radio emission in galaxy clusters and radio galaxies, have not yet been determined. This lower limit, parametrized by the lower limit of the electron momentum - p min - is critical for estimating the total energetics of non-thermal electrons produced by cluster mergers or injected by radio galaxy jets, which impacts the formation of large-scale structure in the universe, as well as the evolution of local structures inside galaxy clusters. The total pressure due to the relativistic, non-thermal population of electrons can be measured using the Sunyaev-Zel'dovich Effect, and is critically dependent on p min , making the measurement of this non-thermal pressure a promising technique to estimate the electron low-energy cutoff. We present here the first unambiguous detection of this Sunyaev-Zel'dovich Effect for a non-thermal population of electrons in a radio galaxy jet/lobe, located at a significant distance away from the center of the Bullet cluster of galaxies.

Electron collisions with phenol: Total, integral, differential, and momentum transfer cross sections and the role of multichannel coupling effects on the elastic channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Costa, Romarly F. da; Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, São Paulo; Oliveira, Eliane M. de

2015-03-14

We report theoretical and experimental total cross sections for electron scattering by phenol (C{sub 6}H{sub 5}OH). The experimental data were obtained with an apparatus based in Madrid and the calculated cross sections with two different methodologies, the independent atom method with screening corrected additivity rule (IAM-SCAR), and the Schwinger multichannel method with pseudopotentials (SMCPP). The SMCPP method in the N{sub open}-channel coupling scheme, at the static-exchange-plus-polarization approximation, is employed to calculate the scattering amplitudes at impact energies ranging from 5.0 eV to 50 eV. We discuss the multichannel coupling effects in the calculated cross sections, in particular how the numbermore » of excited states included in the open-channel space impacts upon the convergence of the elastic cross sections at higher collision energies. The IAM-SCAR approach was also used to obtain the elastic differential cross sections (DCSs) and for correcting the experimental total cross sections for the so-called forward angle scattering effect. We found a very good agreement between our SMCPP theoretical differential, integral, and momentum transfer cross sections and experimental data for benzene (a molecule differing from phenol by replacing a hydrogen atom in benzene with a hydroxyl group). Although some discrepancies were found for lower energies, the agreement between the SMCPP data and the DCSs obtained with the IAM-SCAR method improves, as expected, as the impact energy increases. We also have a good agreement among the present SMCPP calculated total cross section (which includes elastic, 32 inelastic electronic excitation processes and ionization contributions, the latter estimated with the binary-encounter-Bethe model), the IAM-SCAR total cross section, and the experimental data when the latter is corrected for the forward angle scattering effect [Fuss et al., Phys. Rev. A 88, 042702 (2013)].« less

An investigation of solar flares and associated solar radio bursts impact on ionospheric total electron content

NASA Astrophysics Data System (ADS)

Tuyizere, Sarathiel

2016-07-01

Solar transients events such as Coronal Mass Ejections (CMEs) and solar flares represent the cause of various aspects of space weather and can impact the modern man made technological system. Such solar transients are often associated with solar radio bursts (SRBs), particularly of type II and III that , at ground level can be detected by the CALLISTO (Compact Astronomical Low-frequency Low-cost Instrument for Spectroscopy and Transportable Observatories) solar spectrometer. The present study aims at investigating solar flares and associated SRBs impact on the ionospheric total electron content (TEC). SRBs data used are dynamic spectra covering the 2014-2015 period and detected by the CALLISTO instrument that is installed at the university of Rwanda, Kigali. To investigate ionospheric impact, we use TEC data from IGS stations located at almost the same universal time zone, and correlate the observed TEC changes to the corresponding observed solar bursts events. Preliminary observations resulting from this study indicate a slight enhancement in TEC during the burst event days. The observed TEC enhancement on the burst day can be associated to increased UV and X-rays radiations and particle acceleration that are associated with SRBs events. This work is a contribution to more understanding of the geo-space impact of solar transients phenomena for modeling and prediction.

Magnetically confined electron beam system for high resolution electron transmission-beam experiments

NASA Astrophysics Data System (ADS)

Lozano, A. I.; Oller, J. C.; Krupa, K.; Ferreira da Silva, F.; Limão-Vieira, P.; Blanco, F.; Muñoz, A.; Colmenares, R.; García, G.

2018-06-01

A novel experimental setup has been implemented to provide accurate electron scattering cross sections from molecules at low and intermediate impact energies (1-300 eV) by measuring the attenuation of a magnetically confined linear electron beam from a molecular target. High-resolution electron energy is achieved through confinement in a magnetic gas trap where electrons are cooled by successive collisions with N2. Additionally, we developed and present a method to correct systematic errors arising from energy and angular resolution limitations. The accuracy of the entire measurement procedure is validated by comparing the N2 total scattering cross section in the considered energy range with benchmark values available in the literature.

Ontological modeling of electronic health information exchange.

PubMed

McMurray, J; Zhu, L; McKillop, I; Chen, H

2015-08-01

Investments of resources to purposively improve the movement of information between health system providers are currently made with imperfect information. No inventories of system-level electronic health information flows currently exist, nor do measures of inter-organizational electronic information exchange. Using Protégé 4, an open-source OWL Web ontology language editor and knowledge-based framework, we formalized a model that decomposes inter-organizational electronic health information flow into derivative concepts such as diversity, breadth, volume, structure, standardization and connectivity. The ontology was populated with data from a regional health system and the flows were measured. Individual instance's properties were inferred from their class associations as determined by their data and object property rules. It was also possible to visualize interoperability activity for regional analysis and planning purposes. A property called Impact was created from the total number of patients or clients that a health entity in the region served in a year, and the total number of health service providers or organizations with whom it exchanged information in support of clinical decision-making, diagnosis or treatment. Identifying providers with a high Impact but low Interoperability score could assist planners and policy-makers to optimize technology investments intended to electronically share patient information across the continuum of care. Finally, we demonstrated how linked ontologies were used to identify logical inconsistencies in self-reported data for the study. Copyright © 2015 Elsevier Inc. All rights reserved.

Polarization correlation study of the electron-impact excitation of neon and argon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khakoo, M.A.; McConkey, J.W.

1986-08-11

The recent development of a circular polarization analyzer for the vacuum ultraviolet spectral region has enabled a Stokes parameter analysis to be carried out for the excitation of neon and argon by 80-eV incident electrons. The results show that the transfer of angular momentum to the atom is positive and is in fact surprisingly ''heliumlike.'' Small deviations from total coherence were observed and are discussed.

Chapter 6 Quantum Mechanical Methods for Loss-Excitation and Loss-Ionization in Fast Ion-Atom Collisions

NASA Astrophysics Data System (ADS)

Belkic, Dzevad

Inelastic collisions between bare nuclei and hydrogen-like atomic systems are characterized by three main channels: electron capture, excitation, and ionization. Capture dominates at lower energies, whereas excitation and ionization prevail at higher impact energies. At intermediate energies and in the region of resonant scattering near the Massey peak, all three channels become competitive. For dressed or clothed nuclei possessing electrons, such as hydrogen-like ions, several additional channels open up, including electron loss (projectile ionization or stripping). The most important aspect of electron loss is the competition between one- and two-electron processes. Here, in a typical one-electron process, the projectile emits an electron, whereas the target final and initial states are the same. A prototype of double-electron transitions in loss processes is projectile ionization accompanied with an alteration of the target state. In such a two-electron process, the target could be excited or ionized. The relative importance of these loss channels with single- and double-electron transitions involving collisions of dressed projectiles with atomic systems is also strongly dependent on the value of the impact energy. Moreover, impact energies determine which theoretical method is likely to be more appropriate to use for predictions of cross sections. At low energies, an expansion of total scattering wave functions in terms of molecular orbitals is adequate. This is because the projectile spends considerable time in the vicinity of the target, and as a result, a compound system comprised of the projectile and the target can be formed in a metastable molecular state which is prone to decay. At high energies, a perturbation series expansion is more appropriate in terms of powers of interaction potentials. In the intermediate energy region, atomic orbitals are often used with success while expanding the total scattering wave functions. The present work is focused on quantum mechanical perturbation theories applied to electron loss collisions involving two hydrogen-like atoms. Both the one- and two-electron transitions (target unaffected by collision, as well as loss-ionization) are thoroughly examined in various intervals of impact energies varying from the threshold via the Massey peak to the Bethe asymptotic region. Systematics are established for the fast, simple, and accurate computations of cross sections for loss-excitation and loss-ionization accounting for the entire spectra of all four particles, including two free electrons and two free protons. The expounded algorithmic strategy of quantum mechanical methodologies is of great importance for wide applications to particle transport physics, especially in fusion research and hadron radiotherapy. This should advantageously replace the current overwhelming tendency in these fields for using phenomenological modeling with artificial functions extracted from fitting the existing experimental/theoretical data bases for cross sections.

Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural

NASA Astrophysics Data System (ADS)

Jones, D. B.; da Costa, R. F.; Varella, M. T. do N.; Bettega, M. H. F.; Lima, M. A. P.; Blanco, F.; García, G.; Brunger, M. J.

2016-04-01

We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20-250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arise due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron-furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.

SUPRATHERMAL ELECTRONS IN TITAN’S SUNLIT IONOSPHERE: MODEL–OBSERVATION COMPARISONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vigren, E.; Edberg, N. J. T.; Wahlund, J.-E.

2016-08-01

The dayside ionosphere of the Saturnian satellite Titan is generated mainly from photoionization of N{sub 2} and CH{sub 4}. We compare model-derived suprathermal electron intensities with spectra measured by the Cassini Plasma Spectrometer/Electron Spectrometer (CAPS/ELS) in Titan's sunlit ionosphere (altitudes of 970–1250 km) focusing on the T40, T41, T42, and T48 Titan flybys by the Cassini spacecraft. The model accounts only for photoelectrons and associated secondary electrons, with a main input being the impinging solar EUV spectra as measured by the Thermosphere Ionosphere Mesosphere Energy and Dynamics/Solar EUV Experiment and extrapolated to Saturn. Associated electron-impact electron production rates have beenmore » derived from ambient number densities of N{sub 2} and CH{sub 4} (measured by the Ion Neutral Mass Spectrometer/Closed Source Neutral mode) and related energy-dependent electron-impact ionization cross sections. When integrating up to electron energies of 60 eV, covering the bulk of the photoelectrons, the model-based values exceed the observationally based values typically by factors of ∼3 ± 1. This finding is possibly related to current difficulties in accurately reproducing the observed electron number densities in Titan's dayside ionosphere. We compare the utilized dayside CAPS/ELS spectra with ones measured in Titan's nightside ionosphere during the T55–T59 flybys. The investigated nightside locations were associated with higher fluxes of high-energy (>100 eV) electrons than the dayside locations. As expected, for similar neutral number densities, electrons with energies <60 eV give a higher relative contribution to the total electron-impact ionization rates on the dayside (due to the contribution from photoelectrons) than on the nightside.« less

Simple method for determining fullerene negative ion formation★

NASA Astrophysics Data System (ADS)

Felfli, Zineb; Msezane, Alfred Z.

2018-04-01

A robust potential wherein is embedded the crucial core-polarization interaction is used in the Regge-pole methodology to calculate low-energy electron elastic scattering total cross section for the C60 fullerene in the electron impact energy range 0.02 ≤ E ≤ 10.0 eV. The energy position of the characteristic dramatically sharp resonance appearing at the second Ramsauer-Townsend minimum of the total cross section representing stable C60 - fullerene negative ion formation agrees excellently with the measured electron affinity of C60 [Huang et al., J. Chem. Phys. 140, 224315 (2014)]. The benchmarked potential and the Regge-pole methodology are then used to calculate electron elastic scattering total cross sections for selected fullerenes, from C54 through C240. The total cross sections are found to be characterized generally by Ramsauer-Townsend minima, shape resonances and dramatically sharp resonances representing long-lived states of fullerene negative ion formation. For the total cross sections of C70, C76, C78, and C84 the agreement between the energy positions of the very sharp resonances and the measured electron affinities is outstanding. Additionally, we compare our extracted energy positions of the resultant fullerene anions from our calculated total cross sections of the C86, C90 and C92 fullerenes with the estimated electron affinities ≥3.0 eV by the experiment [Boltalina et al., Rapid Commun. Mass Spectrom. 7, 1009 (1993)]. Resonance energy positions of other fullerenes, including C180 and C240 are also obtained. Most of the total cross sections presented in this paper are the first and only; our novel approach is general and should be applicable to other fullerenes as well and complex heavy atoms, such as the lanthanide atoms. We conclude with a remark on the catalytic properties of the fullerenes through their negative ions.

Critical Assessment of Theoretical Methods for Li3+ Collisions with He at Intermediate and High Impact Energies

NASA Astrophysics Data System (ADS)

Belkić, Dževad; Mančev, Ivan; Milojevićb, Nenad

2013-09-01

The total cross sections for the various processes for Li3+-He collisions at intermediate-to-high impact energies are compared with the corresponding theories. The possible reasons for the discrepancies among various theoretical predictions are thoroughly discussed. Special attention has been paid to single and double electron capture, simultaneous transfer and ionization, as well as to single and double ionization.

Radiative-emission analysis in charge-exchange collisions of O6 + with argon, water, and methane

NASA Astrophysics Data System (ADS)

Leung, Anthony C. K.; Kirchner, Tom

2017-04-01

Processes of electron capture followed by Auger and radiative decay were investigated in slow ion-atom and -molecule collisions. A quantum-mechanical analysis which utilizes the basis generator method within an independent electron model was carried out for collisions of O 6 + with Ar, H2O , and CH4 at impact energies of 1.17 and 2.33 keV/amu. At these impact energies, a closure approximation in the spectral representation of the Hamiltonian for molecules was found to be necessary to yield reliable results. Total single-, double-, and triple-electron-capture cross sections obtained show good agreement with previous measurements and calculations using the classical trajectory Monte Carlo method. The corresponding emission spectra from single capture for each collision system are in satisfactory agreement with previous calculations.

An investigation of solar flares and associated solar radio bursts on ionospheric total electron content

NASA Astrophysics Data System (ADS)

Uwamahoro, Jean

2016-07-01

Solar transients events such as Coronal Mass Ejections (CMEs) and solar flares represent are the cause of various aspects of space weather and can impact the modern man made technological system. Such solar transients are often associated with solar radio bursts (SRBs), particularly of type II and III that , at ground level can be detected by the CALLISTO (Compact Astronomical Low-frequency Low-cost Instrument for Spectroscopy and Transportable Observatories) solar spectrometer. The present study aims at investigating solar flares and associated SRBs impact on the ionospheric total electron content (TEC). SRBs data used are dynamic spectra covering the 2014-2015 period and detected by the CALLISTO instrument that is installed at the university of Rwanda, Kigali. To investigate ionospheric impact, we use TEC data from IGS stations located at almost the same universal time zone, and correlate the observed TEC changes to the corresponding observed solar bursts events. Preliminary observations resulting from this study indicate a slight enhancement in TEC during the burst event days. The observed TEC enhancement on the burst day can be associated to increased UV and X-rays radiations and particle acceleration that are associated with SRBs events. This work is a contribution to more understanding of the geo-space impact of solar transients phenomena for modeling and prediction.

Ionizing Collisions of Electrons with Radical Species OH, H2 O2 and HO2; Theoretical Calculations

NASA Astrophysics Data System (ADS)

Joshipura, K. N.; Pandya, S. H.; Vaishnav, B. G.; Patel, U. R.

2016-05-01

In this paper we present our calculated total ionization cross sections (TICS) of electron impact on radical targets OH, H2 O2 and HO2 at energies from threshold to 2000 eV. Reactive species such as these pose difficulties in measurements of electron scattering cross sections. No measured data have been reported in this regard except an isolated TICS measurement on OH radical, and hence the present work on the title radicals hold significance. These radical species are present in an environment in which water molecules undergo dissociation (neutral or ionic) in interactions with photons or electrons. The embedding environments could be quite diverse, ranging from our atmosphere to membranes of living cells. Ionization of OH, H2 O2 or HO2 can give rise to further chemistry in the relevant bulk medium. Therefore, it is appropriate and meaningful to examine electron impact ionization of these radicals in comparison with that of water molecules, for which accurate da are available. For the OH target single-centre scattering calculations are performed by starting with a 4-term complex potential, that describes simultaneous elastic plus inelastic scattering. TICS are obtained from the total inelastic cross sections in the complex scattering potential - ionization contribution formalism , a well established method. For H2 O2 and HO2 targets, we employ the additivity rule with overlap or screening corrections. Detailed results will be presented in the Conference.

Following electron impact excitations of Rn, Ra, Th, U and Pu single atom L sub-shells ionization cross section calculations by using Lotz’s equation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ayinol, M., E-mail: aydinolm@dicle.edu.tr; Aydeniz, D., E-mail: daydeniz@hotmail.com

L shell ionization cross section and L{sub i} subshells ionization cross sections of Rn, Ra, Th, U, Pu atoms calculated. For each of atoms, ten different electron impact energy values (E{sub o}) are used. Calculations carried out by using Lotz equation in Matlab. First, calculations done for non-relativistic case by using non-relativistic Lotz equation then repeated with relativistic Lotz equation. σ{sub L} total and σ{sub Li}(i = 1,2,3) subshells ionisation cross section values obtained for E{sub o} values in the energy range of E{sub Li}

Electron impact excitation of molecular hydrogen

DOE PAGES

Zammit, Mark Christian; Savage, Jeremy S.; Fursa, Dmitry V.; ...

2017-02-06

Here, we report the electron impact integrated and differential cross sections for excitation to the b 3Σmore » $$+\\atop{u}$$, a 3Σ$$+\\atop{g}$$, c 3Π u, B 1Σ$$+\\atop{u}$$, E, F 1Σ$$+\\atop{g}$$, C 1Π u, e 3Σ$$+\\atop{u}$$, h 3Σ $$+\\atop{g}$$, d 3Π u, B'' 1Σ$$+\\atop{u}$$ , D 1Π u, B'' 1Σ$$+\\atop{u}$$, and D' 1Π u states of molecular hydrogen in the energy range from 10 to 300 eV. Total scattering and total ionization cross sections are also presented. The calculations have been performed by using the convergent close-coupling method within the fixed-nuclei approximation. Detailed convergence studies have been performed with respect to the size of the close-coupling expansion and a set of recommended cross sections has been produced. Significant differences with previous calculations are found. Agreement with experiment is mixed, ranging from excellent to poor depending on the transition and incident energies.« less

Fundamental mechanisms of laser damage of dielectric crystals by ultrashort pulse: ionization dynamics for the Keldysh model

NASA Astrophysics Data System (ADS)

Gruzdev, Vitaly

2014-12-01

Laser-induced ionization is a major process that initiates and drives the initial stages of laser-induced damage (LID) of high-quality transparent solids. The ionization and its contribution to LID are characterized in terms of the time-dependent ionization rate and conduction-band electron density. Considering femtosecond pulses of various durations (from 35 to 706 fs) and variable peak irradiances (from 0.01 to 60 TW/cm2), we use a single-rate equation to simulate time variations of conduction-band electron density and rates of the photoionization and impact ionization. The photoionization rate is evaluated with the Keldysh equation. At low irradiance, the electron density and total ionization rate demonstrate power scaling characteristic of multiphoton ionization. With the increase of irradiance, there is observed a saturation of the photoionization rate due to photoionization suppression by the Keldysh-type singularity during the increase in the number of simultaneously absorbed photons by 1. A striking result is that the saturation is followed by a stepwise transition from the ionization regime which is completely dominated by the photoionization to a regime totally dominated by the impact ionization. The transition results in the increase of the electron density by a few orders of magnitude induced by a variation of peak laser irradiance by about 15% to 20%. The physical effects that are involved are discussed.

Adaptation of a hospital electronic referral system for antimicrobial stewardship prospective audit and feedback rounds.

PubMed

Rawlins, Matthew D M; Raby, Edward; Sanfilippo, Frank M; Douglass, Rae; Chambers, Jonathan; McLellan, Duncan; Dyer, John R

2018-05-04

To evaluate the impact of the adaptation of an existing electronic referral application for use in antimicrobial stewardship prospective audit and feedback rounds (antimicrobial rounds). Retrospective, single-centre observational study between March 2015 and February 2016. A new quaternary referral centre. Adults referred for antimicrobial rounds outside of the intensive care and haematology units. Adaptation of an electronic referral application used by medical and allied health staff. A questionnaire-style referral form was designed to capture patient clinical details using a combination of free text and dropdown menus. Clinical pharmacists were educated and granted access to the system. The proportion of completed electronic referrals of total round reviews by month for the 12 months after implementation. The time from request to completion of reviews. The impact on adherence to advice provided on rounds. The impact on the institutional usage of broad-spectrum antibiotics: glycopeptides, carbapenems, third and fourth generation cephalosporins, fluoroquinolones and piperacillin/tazobactam. Over the study period, the proportion of electronic referrals of completed antimicrobial round reviews increased from 59% to 88% (P < 0.001); 75.7% of accepted electronic referrals were seen within 48 h of request. The proportion of advice ignored fell from 18% to 8.5% (P < 0.001). Piperacillin/tazobactam, fluoroquinolone and glycopeptide usage decreased. The adaptation of an electronic referral application for antimicrobial rounds was associated with increased adherence to advice and reduction in use in target antibiotics. Our model is now used at other institutions.

The impact of automating laboratory request forms on the quality of healthcare services.

PubMed

Dogether, Majed Al; Muallem, Yahya Al; Househ, Mowafa; Saddik, Basema; Khalifa, Mohamed

In recent decades, healthcare organizations have undergone a significant transformation with the integration of Information and Communication Technologies within healthcare operations to improve healthcare services. Various technologies such as Hospital Information Systems (HIS), Electronic Health Records (EHR) and Laboratory Information Systems (LIS) have been incorporated into healthcare services. The aim of this study is to evaluate the completeness of outpatients' laboratory paper based request forms in comparison with a electronic laboratory request system. This study was carried out in the laboratory department at King Abdulaziz Medical City (KAMC), National Guard Health Affairs, Riyadh, Saudi Arabia. We used a sample size calculator for comparing two proportions. We estimated the sample size to be 228 for each group. Any laboratory requests including paper and electronic forms were included. We categorized the clarity of the forms into understandable, readable, and unclear. A total of 57 incomplete paper forms or 25% were identified as being incomplete. For electronic forms, there were no incomplete fields, as all fields were mandatory, therefore, rendering them complete. The total of understandable paper-based laboratory forms was 11.4%. Additionally, it was found that the total of readable was 33.8% and the total for unclear was 54.8%, while for electronic-based forms, there were no unclear forms. Electronic based laboratory forms provide a more complete, accurate, clear, and understandable format than paper-based laboratory records. Based on these findings, KAMC should move toward the implementation of electronic-based laboratory request forms for the outpatient laboratory department. Copyright © 2016 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

Low-energy electron-impact ionization of helium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schow, E.; Hazlett, K.; Childers, J. G.

2005-12-15

Normalized doubly differential cross sections for the electron-impact ionization of helium at low energies are presented. The data are taken at the incident electron energies of 26.3, 28.3, 30.3, 32.5, 34.3, 36.5, and 40.7 eV and for scattering angles of 10 deg. -130 deg. The measurements involve the use of the moveable target method developed at California State University Fullerton to accurately determine the continuum background in the energy-loss spectra. Normalization of experimental data is made on a relative scale to well-established experimental differential cross sections for excitation of the n=2 manifold of helium and then on an absolute scalemore » to the well-established total ionization cross sections of Shah et al. [J. Phys. B 21, 2751 (1988)]. Comparisons are made with available experimental data and the results of the convergent close-coupling theory.« less

Electron impact ionization of plasma important SiClX (X = 1-4) molecules: theoretical cross sections

NASA Astrophysics Data System (ADS)

Kothari, Harshit N.; Pandya, Siddharth H.; Joshipura, K. N.

2011-06-01

Electron impact ionization of SiClX (X = 1-4) molecules is less studied but an important process for understanding and modelling the interactions of silicon-chlorine plasmas with different materials. The SiCl3 radical is a major chloro-silicon species involved in the CVD (chemical vapour deposition) of silicon films from SiCl4/Ar microwave plasmas. We report in this paper the total ionization cross sections for electron collisions on these silicon compounds at incident energies from the ionization threshold to 2000 eV. We employ the 'complex scattering potential-ionization contribution' method and identify the relative importance of various channels, with ionization included in the cumulative inelastic scattering. New results are also presented on these exotic molecular targets. This work is significant in view of the paucity of theoretical studies on the radicals SiClX (X = 1-3) and on SiCl4.

Cross-section and rate formulas for electron-impact ionization, excitation, deexcitation, and total depopulation of excited atoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vriens, L.; Smeets, A.H.M.

1980-09-01

For electron-induced ionization, excitation, and de-excitation, mainly from excited atomic states, a detailed analysis is presented of the dependence of the cross sections and rate coefficients on electron energy and temperature, and on atomic parameters. A wide energy range is covered, including sudden as well as adiabatic collisions. By combining the available experimental and theoretical information, a set of simple analytical formulas is constructed for the cross sections and rate coefficients of the processes mentioned, for the total depopulation, and for three-body recombination. The formulas account for large deviations from classical and semiclassical scaling, as found for excitation. They agreemore » with experimental data and with the theories in their respective ranges of validity, but have a wider range of validity than the separate theories. The simple analytical form further facilitates the application in plasma modeling.« less

Born distorted-wave approximation applied to the H+ + He collisions at intermediate and high energies

NASA Astrophysics Data System (ADS)

Rahmanian, M.; Fathi, R.; Shojaei, F.

2017-11-01

The single-charge transfer process in collision of protons with helium atoms in their ground states is investigated. The model utilizes the second-order three-body Born distorted-wave approximation (BDW-3B) with correct Coulomb boundary conditions to calculate the differential and total cross sections at intermediate and high energies. The role of the passive electrons and electron-electron correlations are studied by comparing our results and the BDW-4B calculations with the complete perturbation potential. The present results are also compared with other theories, and the Thomas scattering mechanism is investigated. The obtained results are also compared with the recent experimental measurements. For the prior differential cross sections, the comparisons show better agreement with the experiments at smaller scattering angles. The agreement between the total cross sections and the BDW-4B results as well as the experimental data is good at higher impact energies.

Academic impact of a public electronic health database: bibliometric analysis of studies using the general practice research database.

PubMed

Chen, Yu-Chun; Wu, Jau-Ching; Haschler, Ingo; Majeed, Azeem; Chen, Tzeng-Ji; Wetter, Thomas

2011-01-01

Studies that use electronic health databases as research material are getting popular but the influence of a single electronic health database had not been well investigated yet. The United Kingdom's General Practice Research Database (GPRD) is one of the few electronic health databases publicly available to academic researchers. This study analyzed studies that used GPRD to demonstrate the scientific production and academic impact by a single public health database. A total of 749 studies published between 1995 and 2009 with 'General Practice Research Database' as their topics, defined as GPRD studies, were extracted from Web of Science. By the end of 2009, the GPRD had attracted 1251 authors from 22 countries and been used extensively in 749 studies published in 193 journals across 58 study fields. Each GPRD study was cited 2.7 times by successive studies. Moreover, the total number of GPRD studies increased rapidly, and it is expected to reach 1500 by 2015, twice the number accumulated till the end of 2009. Since 17 of the most prolific authors (1.4% of all authors) contributed nearly half (47.9%) of GPRD studies, success in conducting GPRD studies may accumulate. The GPRD was used mainly in, but not limited to, the three study fields of "Pharmacology and Pharmacy", "General and Internal Medicine", and "Public, Environmental and Occupational Health". The UK and United States were the two most active regions of GPRD studies. One-third of GRPD studies were internationally co-authored. A public electronic health database such as the GPRD will promote scientific production in many ways. Data owners of electronic health databases at a national level should consider how to reduce access barriers and to make data more available for research.

Quantum Shielding Effects on the Eikonal Collision Cross Section in Strongly Coupled Two-temperature Plasmas

NASA Astrophysics Data System (ADS)

Lee, Myoung-Jae; Jung, Young-Dae

2017-05-01

The influence of nonisothermal and quantum shielding on the electron-ion collision process is investigated in strongly coupled two-temperature plasmas. The eikonal method is employed to obtain the eikonal scattering phase shift and eikonal cross section as functions of the impact parameter, collision energy, electron temperature, ion temperature, Debye length, and de Broglie wavelength. The results show that the quantum effect suppresses the eikonal scattering phase shift for the electron-ion collision in two-temperature dense plasmas. It is also found that the differential eikonal cross section decreases for small impact parameters. However, it increases for large impact parameters with increasing de Broglie wavelength. It is also found that the maximum position of the differential eikonal cross section is receded from the collision center with an increase in the nonisothermal character of the plasma. In addition, it is found that the total eikonal cross sections in isothermal plasmas are always greater than those in two-temperature plasmas. The variations of the eikonal cross section due to the two-temperature and quantum shielding effects are also discussed.

Theory of electron-impact ionization of atoms

NASA Astrophysics Data System (ADS)

Kadyrov, A. S.; Mukhamedzhanov, A. M.; Stelbovics, A. T.; Bray, I.

2004-12-01

The existing formulations of electron-impact ionization of a hydrogenic target suffer from a number of formal problems including an ambiguous and phase-divergent definition of the ionization amplitude. An alternative formulation of the theory is given. An integral representation for the ionization amplitude which is free of ambiguity and divergence problems is derived and is shown to have four alternative, but equivalent, forms well suited for practical calculations. The extension to amplitudes of all possible scattering processes taking place in an arbitrary three-body system follows. A well-defined conventional post form of the breakup amplitude valid for arbitrary potentials including the long-range Coulomb interaction is given. Practical approaches are based on partial-wave expansions, so the formulation is also recast in terms of partial waves and partial-wave expansions of the asymptotic wave functions are presented. In particular, expansions of the asymptotic forms of the total scattering wave function, developed from both the initial and the final state, for electron-impact ionization of hydrogen are given. Finally, the utility of the present formulation is demonstrated on some well-known model problems.

Effect of static electronic advertising signs on road safety: an experimental case study.

PubMed

Izadpanah, Pedram; Omrani, Reza; Koo, Sheldon; Hadayeghi, Ali

2014-01-01

As technology continues to advance, the outdoor advertising industry is taking advantage of electronic signs, some of which are static electronic signs (SES), with the ability to automatically change the message shown on the sign at regular intervals. Studies indicate that SES has a negative impact on the drivers' visual attention and on vehicle control. However, the actual effects of the SES on the number of collisions have been difficult to prove conclusively. The objective of this article is to generate a clear understanding of the safety impacts of SES on the number collisions by conducting a before-and-after analysis with comparison groups. The analysis was based on a total of 10 SES along the Highway 27 and the Gardiner Expressway of the city of Toronto. The results of the before-and-after study revealed that there was not enough evidence to suggest that these signs have any impact on road safety along the adjacent roadway sections at a 95% confidence interval. The same results were obtained by comparing collisions that occurred during daylight and artificial light.

The role of physics in shaping music

NASA Astrophysics Data System (ADS)

Townsend, Peter

2015-07-01

Physics and technology have played a major role in shaping the development, performance, interpretation and composition of music for many centuries. From the twentieth century, electronics and communications have provided recording and broadcasting that gives access to worldwide music and performers of many musical genres. Early scientific influence came via improved or totally new instruments, plus larger and better concert halls. Instrument examples range from developments of violins or pianos to keyed and valved wood wind and brass that offer chromatic performance. New sounds appeared by inventions of totally new instruments, such as the saxophone or the Theremin, to all the modern electronic influence on keyboards and synthesisers. Electronic variants of guitars are effectively new instruments that have spawned totally original musical styles. All such advances have encouraged more virtuosic performance, larger halls, a wider range of audiences and a consequent demand and ability of composers to meet the new challenges. Despite this immense impact, the role of physics and technology over the last few centuries has mostly been ignored, although it was often greater than any links to arts or culture. Recorded and broadcast music has enhanced our expectations on performance and opened gateways to purely electronically generated sounds, of the now familiar electronic keyboards and synthesisers. This brief review traces some of the highlights in musical evolution that were enabled by physics and technology and their impact on the musical scene. The pattern from the past is clear, and so some of the probable advances in the very near future are also predicted. Many are significant as they will impinge on our appreciation of both current and past music, as well as compositional styles. Mention is made of the difference in sound between live and recorded music and the reasons why none of us ever have precisely the same musical experience twice, even from the same recording. Similarly, it is impossible to appreciate earlier music from the same perspective as occurred when it was first composed and performed, or indeed from later interpretations.

Impact of an electronic medication administration record on medication administration efficiency and errors.

PubMed

McComas, Jeffery; Riingen, Michelle; Chae Kim, Son

2014-12-01

The study aims were to evaluate the impact of electronic medication administration record implementation on medication administration efficiency and occurrence of medication errors as well as to identify the predictors of medication administration efficiency in an acute care setting. A prospective, observational study utilizing time-and-motion technique was conducted before and after electronic medication administration record implementation in November 2011. A total of 156 cases of medication administration activities (78 pre- and 78 post-electronic medication administration record) involving 38 nurses were observed at the point of care. A separate retrospective review of the hospital Midas+ medication error database was also performed to collect the rates and origin of medication errors for 6 months before and after electronic medication administration record implementation. The mean medication administration time actually increased from 11.3 to 14.4 minutes post-electronic medication administration record (P = .039). In a multivariate analysis, electronic medication administration record was not a predictor of medication administration time, but the distractions/interruptions during medication administration process were significant predictors. The mean hospital-wide medication errors significantly decreased from 11.0 to 5.3 events per month post-electronic medication administration record (P = .034). Although no improvement in medication administration efficiency was observed, electronic medication administration record improved the quality of care with a significant decrease in medication errors.

Addressing the Influence of Space Weather on Airline Navigation

NASA Technical Reports Server (NTRS)

Sparks, Lawrence

2012-01-01

The advent of satellite-based augmentation systems has made it possible to navigate aircraft safely using radio signals emitted by global navigation satellite systems (GNSS) such as the Global Positioning System. As a signal propagates through the earth's ionosphere, it suffers delay that is proportional to the total electron content encountered along the raypath. Since the magnitude of this total electron content is strongly influenced by space weather, the safety and reliability of GNSS for airline navigation requires continual monitoring of the state of the ionosphere and calibration of ionospheric delay. This paper examines the impact of space weather on GNSS-based navigation and provides an overview of how the Wide Area Augmentation System protects its users from positioning error due to ionospheric disturbances

Ratios of double to single ionization of He and Ne by strong 400-nm laser pulses using the quantitative rescattering theory

NASA Astrophysics Data System (ADS)

Chen, Zhangjin; Li, Xiaojin; Zatsarinny, Oleg; Bartschat, Klaus; Lin, C. D.

2018-01-01

We present numerical simulations of the ratio between double and single ionization of He and Ne by intense laser pulses at wavelengths of 390 and 400 nm, respectively. The yields of doubly charged ions due to nonsequential double ionization (NSDI) are obtained by employing the quantitative rescattering (QRS) model. In this model, the NSDI ionization probability is expressed as a product of the returning electron wave packet (RWP) and the total scattering cross sections for laser-free electron impact excitation and electron impact ionization of the parent ion. According to the QRS theory, the same RWP is also responsible for the emission of high-energy above-threshold ionization photoelectrons. To obtain absolute double-ionization yields, the RWP is generated by solving the time-dependent Schrödinger equation (TDSE) within a one-electron model. The same TDSE results can also be taken to obtain single-ionization yields. By using the TDSE results to calibrate single ionization and the RWP obtained from the strong-field approximation, we further simplify the calculation such that the nonuniform laser intensity distribution in the focused laser beam can be accounted for. In addition, laser-free electron impact excitation and ionization cross sections are calculated using the state-of-the-art many-electron R -matrix theory. The simulation results for double-to-single-ionization ratios are found to compare well with experimental data and support the validity of the nonsequential double-ionization mechanism for the covered intensity region.

An (e, 2e+ ion) study of electron-impact ionization and fragmentation of tetrafluoromethane at low energies

NASA Astrophysics Data System (ADS)

Hossen, Khokon; Ren, Xueguang; Wang, Enliang; Kumar, S. V. K.; Dorn, Alexander

2018-03-01

We study ionization and fragmentation of tetrafluoromethane (CF4) molecule induced by electron impact at low energies ( E 0 = 38 and 67 eV). We use a reaction microscope combined with a pulsed photoemission electron beam for our experimental investigation. The momentum vectors of the two outgoing electrons (energies E 1, E 2) and one fragment ion are detected in triple coincidence (e, 2e+ ion). After dissociation, the fragment products observed are CF3 +, CF2 +, CF+, F+ and C+. For CF3 + and CF2 + channels, we measure the ionized orbitals binding energies, the kinetic energy (KE) of the charged fragments and the two-dimensional (2D) correlation map between binding energy (BE) and KE of the fragments. From the BE and KE spectra, we conclude which molecular orbitals contribute to particular fragmentation channels of CF4. We also measure the total ionization cross section for the formation of CF3 + and CF2 + ions as function of projectile energy. We compare our results with earlier experiments and calculations for electron-impact and photoionization. The major contribution to CF3 + formation originates from ionization of the 4t2 orbital while CF2 + is mainly formed after 3t2 orbital ionization. We also observe a weak contribution of the (4a1)-1 state for the channel CF3 +.

Fluid simulation of species concentrations in capacitively coupled N2/Ar plasmas: Effect of gas proportion

NASA Astrophysics Data System (ADS)

Liang, Ying-Shuang; Liu, Gang-Hu; Xue, Chan; Liu, Yong-Xin; Wang, You-Nian

2017-05-01

A two-dimensional self-consistent fluid model and the experimental diagnostic are employed to investigate the dependencies of species concentrations on the gas proportion in the capacitive N2/Ar discharges operated at 60 MHz, 50 Pa, and 140 W. The results indicate that the N2/Ar proportion has a considerable impact on the species densities. As the N2 fraction increases, the electron density, as well as the Ar+ and Arm densities, decreases remarkably. On the contrary, the N2 + density is demonstrated to increase monotonically with the N2 fraction. Moreover, the N density is observed to increase significantly with the N2 fraction at the N2 fractions below 40%, beyond which it decreases slightly. The electrons are primarily generated via the electron impact ionization of the feed gases. The electron impact ionization of Ar essentially determines the Ar+ density. For the N2 + production, the charge transition process between the Ar+ ions and the feed gas N2 dominates at low N2 fraction, while the electron impact ionization of N2 plays the more important role at high N2 fraction. At any gas mixtures, more than 60% Arm atoms are generated through the radiative decay process from Ar(4p). The dissociation of the feed gas N2 by the excited Ar atoms and by the electrons is responsible for the N formation at low N2 fraction and high N2 fraction, respectively. To validate the simulation results, the floating double probe and the optical emission spectroscopy are employed to measure the total positive ion density and the emission intensity originating from Ar(4p) transitions, respectively. The results from the simulation show a qualitative agreement with that from the experiment, which indicates the reliable model.

Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, D. B.; Costa, R. F. da; Departamento de Física, Universidade Federal do Espírito Santo, 29075-910, Vitória, Espírito Santo

We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20–250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arisemore » due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron–furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.« less

Electron-helium S-wave model benchmark calculations. II. Double ionization, single ionization with excitation, and double excitation

NASA Astrophysics Data System (ADS)

Bartlett, Philip L.; Stelbovics, Andris T.

2010-02-01

The propagating exterior complex scaling (PECS) method is extended to all four-body processes in electron impact on helium in an S-wave model. Total and energy-differential cross sections are presented with benchmark accuracy for double ionization, single ionization with excitation, and double excitation (to autoionizing states) for incident-electron energies from threshold to 500 eV. While the PECS three-body cross sections for this model given in the preceding article [Phys. Rev. A 81, 022715 (2010)] are in good agreement with other methods, there are considerable discrepancies for these four-body processes. With this model we demonstrate the suitability of the PECS method for the complete solution of the electron-helium system.

Impact of ASTM Standard E722 update on radiation damage metrics

DOE Office of Scientific and Technical Information (OSTI.GOV)

DePriest, Kendall Russell

2014-06-01

The impact of recent changes to the ASTM Standard E722 is investigated. The methodological changes in the production of the displacement kerma factors for silicon has significant impact for some energy regions of the 1-MeV(Si) equivalent fluence response function. When evaluating the integral over all neutrons energies in various spectra important to the SNL electronics testing community, the change in the response results in an increase in the total 1-MeV(Si) equivalent fluence of 2 7%. Response functions have been produced and are available for users of both the NuGET and MCNP codes.

Nitric Oxide Produced by Energetic Electron Precipitation During a Geomagnetic Storm in April 2010

NASA Astrophysics Data System (ADS)

Smith-Johnsen, C.; Nesse, T. H.; Glesnes Ødegaard, L. K.; Orsolini, Y.; Stordal, F.; Hendrickx, K.; Megner, L. S.

2015-12-01

In April 2010 a relativistic electron precipitation (REP) event occurred. A coronal mass ejection (CME) caused the Dst-index to reach -80nT, followed by solar wind speeds of over 600 km/s lasting for three days. Electron fluxes measured by the NOAA POES satellites were increased by an order of magnitude and stayed elevated for three days. We investigate the atmospheric nitric oxide (NO) response to these incoming energetic electrons. By combining the low and medium energy electron fluxes from the Total Energy Detector (TED) and Medium Energy Proton and Electron Detector (MEPED) on the NOAA POES satellites we get a continuous energy spectrum ranging from 1-1100 keV, which corresponds to atmospheric altitudes of 50-150km. The multiple NOAA satellites enables us to construct global maps of the precipitating electrons. The energy spectra of the incoming electron fluxes are compared to NO measurements from The Solar Occultation for Ice Experiment (SOFIE) on board the Aeronomy of Ice in the Mesosphere (AIM) satellite and NO from Sub-Millimeter Radiometer (SMR) on the Odin satellite. The correlation between the incoming electrons and the increase of NO is strongly affected by NO's long lifetime when not exposed to sunlight. Winds from Whole Atmosphere Community Climate Model (WACCM) and the empirical wind model HWM07 are used to take into account the transport of NO in order to understand the total impact of the incoming electrons.

Use of Relativistic Effective Core Potentials in the Calculation of Electron-Impact Ionization Cross Sections

NASA Technical Reports Server (NTRS)

Huo, Winifred M.; Kim, Yong-Ki

1999-01-01

Based on the Binary-Encounter-Bethe (BEB) model, the advantage of using relativistic effective core potentials (RECP) in the calculation of total ionization cross sections of heavy atoms or molecules containing heavy atoms is discussed. Numerical examples for Ar, Kr, Xe, and WF6 are presented.

Electron-helium S-wave model benchmark calculations. I. Single ionization and single excitation

NASA Astrophysics Data System (ADS)

Bartlett, Philip L.; Stelbovics, Andris T.

2010-02-01

A full four-body implementation of the propagating exterior complex scaling (PECS) method [J. Phys. B 37, L69 (2004)] is developed and applied to the electron-impact of helium in an S-wave model. Time-independent solutions to the Schrödinger equation are found numerically in coordinate space over a wide range of energies and used to evaluate total and differential cross sections for a complete set of three- and four-body processes with benchmark precision. With this model we demonstrate the suitability of the PECS method for the complete solution of the full electron-helium system. Here we detail the theoretical and computational development of the four-body PECS method and present results for three-body channels: single excitation and single ionization. Four-body cross sections are presented in the sequel to this article [Phys. Rev. A 81, 022716 (2010)]. The calculations reveal structure in the total and energy-differential single-ionization cross sections for excited-state targets that is due to interference from autoionization channels and is evident over a wide range of incident electron energies.

Study of electron impact inelastic scattering of chlorine molecule (Cl2)

NASA Astrophysics Data System (ADS)

Yadav, Hitesh; Vinodkumar, Minaxi; Limbachiya, Chetan; Vinodkumar, P. C.

2018-02-01

A theoretical study is carried out for electron interactions with the chlorine molecule (Cl2) for incident energies ranging from 0.01 to 5000 eV. This wide range of energy has allowed us to investigate a variety of processes and report data on symmetric excitation energies, dissociative electron attachment (DEA), total excitation cross sections, and ionization cross section (Q ion) along with total inelastic cross sections (Q inel). The present study is important since Cl2 is a prominent gas for plasma etching and its anionic atoms are important in the etching of semiconductor wafers. In order to compute the total inelastic cross sections, we have employed the ab initio R-matrix method (0.01 to 15 eV) together with the spherical complex optical potential method (∼15 to 5000 eV). The R-matrix calculations are performed using a close coupling method, and we have used DEA estimator via Quantemol-N to calculate the DEA fragmentation and cross sections. The present study finds overall good agreement with the available experimental data. Total excitation and inelastic cross sections of e-{{{Cl}}}2 scattering for a wide energy range (0.01 to 5 keV) are reported for the first time, to the best of our knowledge.

Paediatric electronic infusion calculator: An intervention to eliminate infusion errors in paediatric critical care.

PubMed

Venkataraman, Aishwarya; Siu, Emily; Sadasivam, Kalaimaran

2016-11-01

Medication errors, including infusion prescription errors are a major public health concern, especially in paediatric patients. There is some evidence that electronic or web-based calculators could minimise these errors. To evaluate the impact of an electronic infusion calculator on the frequency of infusion errors in the Paediatric Critical Care Unit of The Royal London Hospital, London, United Kingdom. We devised an electronic infusion calculator that calculates the appropriate concentration, rate and dose for the selected medication based on the recorded weight and age of the child and then prints into a valid prescription chart. Electronic infusion calculator was implemented from April 2015 in Paediatric Critical Care Unit. A prospective study, five months before and five months after implementation of electronic infusion calculator, was conducted. Data on the following variables were collected onto a proforma: medication dose, infusion rate, volume, concentration, diluent, legibility, and missing or incorrect patient details. A total of 132 handwritten prescriptions were reviewed prior to electronic infusion calculator implementation and 119 electronic infusion calculator prescriptions were reviewed after electronic infusion calculator implementation. Handwritten prescriptions had higher error rate (32.6%) as compared to electronic infusion calculator prescriptions (<1%) with a p  < 0.001. Electronic infusion calculator prescriptions had no errors on dose, volume and rate calculation as compared to handwritten prescriptions, hence warranting very few pharmacy interventions. Use of electronic infusion calculator for infusion prescription significantly reduced the total number of infusion prescribing errors in Paediatric Critical Care Unit and has enabled more efficient use of medical and pharmacy time resources.

Influence of nuclear exchange on nonadiabatic electron processes in H(+)+H2 collisions.

PubMed

Errea, L F; Illescas, Clara; Macías, A; Méndez, L; Pons, B; Rabadán, I; Riera, A

2010-12-28

H(+)+H(2) collisions are studied by means of a semiclassical approach that explicitly accounts for nuclear rearrangement channels in nonadiabatic electron processes. A set of classical trajectories is used to describe the nuclear motion, while the electronic degrees of freedom are treated quantum mechanically in terms of a three-state expansion of the collision wavefunction. We describe electron capture and vibrational excitation, which can also involve nuclear exchange and dissociation, in the E = 2-1000 eV impact energy range. We compare dynamical results obtained with two parametrizations of the potential energy surface of H(3)(+) ground electronic state. Total cross sections for E > 10 eV agree with previous results using a vibronic close-coupling expansion, and with experimental data for E < 10 eV. Additionally, some prototypical features of both nuclear and electron dynamics at low E are discussed.

Positron total scattering cross-sections for alkali atoms

NASA Astrophysics Data System (ADS)

Sinha, Nidhi; Singh, Suvam; Antony, Bobby

2018-01-01

Positron-impact total scattering cross-sections for Li, Na, K, Rb, Cs and Fr atoms are calculated in the energy range from 5-5000 eV employing modified spherical complex optical potential formalism. The main aim of this work is to apply this formalism to the less studied positron-target collision systems. The results are compared with previous theoretical and experimental data, wherever available. In general, the present data show overall agreement and consistency with other results. Furthermore, we have done a comparative study of the results to investigate the effect of atomic size on the cross-sections as we descend through the group in the periodic table. We have also plotted a correlation graph of the present total cross-sections with polarizability and number of target electrons. The two correlation plots confirm the credibility and consistency of the present results. Besides, this is the first theoretical attempt to report positron-impact total cross-sections of alkali atoms over such a wide energy range.

Ionising sources in the coma of 67P probed by Rosetta

NASA Astrophysics Data System (ADS)

Heritier, Kevin; Galand, Marina; Henri, Pierre; Eriksson, Anders; Odelstad, Elias; Altwegg, Kathrin; Beth, Arnaud; Broiles, Thomas; Burch, Jim; Carr, Christopher; Cupido, Emanuele; Glassmeier, Karl-Heinz; Nilsson, Hans; Richter, Ingo; Rubin, Martin; Vallieres, Xavier; Vigren, Erik

2017-04-01

An ionospheric model has been developed in order to quantify the ion number density in the coma of 67P/Churyumov-Gerasimenko. The model is driven by Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA)/Cometary Pressure Sensor (COPS) neutral density and assumes isentropic expansion for the neutral density profile. The two ionisation sources considered are photo-ionisation by solar extreme ultraviolet (EUV) radiation and electron-impact ionisation. The EUV radiation is estimated from fluxes measured by the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED)/ Solar EUV Experiment (SEE), taking into account the phase shift and the heliocentric distance ratio; between Earth and comet 67P. The electron-impact ionisation production rates are derived from Rosetta Plasma Consortium (RPC)-Ion and Electron Sensor (IES) integrated electron fluxes and corrected for the S/C potential from RPC/LAngmuir Probe (LAP) measurements. Our results are compared with in situ measurements of the plasma density from RPC-Mutual Impedance Probe (MIP) and RPC-LAP. There is a good agreement between the modelled and RPC observed electron densities. The ionospheric model enables to distinguish the relative contributions of the different sources to the total cometary plasma. At high heliocentric distances, electron-impact ionisation becomes the dominant ionisation source and is enhanced over the winter hemisphere. As the solar activity has decreased since the beginning of the mission in 2014, the relative importance of photo-ionisation has decreased as well. However, at low heliocentric distances, photo-ionisation seems to be the most dominant ionising source, in particular through the perihelion period in summer 2015.

Electron-impact excitation of Rydberg and valence electronic states of nitric oxide: II. Integral cross sections

NASA Astrophysics Data System (ADS)

Brunger, M. J.; Campbell, L.; Cartwright, D. C.; Middleton, A. G.; Mojarrabi, B.; Teubner, P. J. O.

2000-02-01

Integral cross sections (ICSs) for the excitation of 18 excited electronic states, and four composite excited electronic states, in nitric oxide (NO) have been determined for incident electron energies of 15, 20, 30, 40 and 50 eV. These ICSs were derived by extrapolating the respective measured differential cross sections (M J Brunger et al 2000 J. Phys. B: At. Mol. Opt. Phys. 33 783) to 0° and 180° and by performing the appropriate integration. Comparison of the present ICSs with the results of those determined in earlier optical emission measurements, and from theoretical calculations is made. At each incident energy considered, the current ICSs are also summed along with the corresponding elastic and rovibrational excitation ICSs from B Mojarrabi et al (1995 J. Phys. B: At. Mol. Opt. Phys. 28 487) and the ionization cross sections from Rapp and Englander-Golden (1965 J. Chem. Phys. 43 1464), to derive an estimate of the grand total cross sections (GTSs) for e- + NO scattering. The GTSs derived in this manner are compared with the results from independent linear transmission experiments and are found to be entirely consistent with them. The present excited electronic state ICS, and those for elastic and rovibrational excitation from Mojarrabi et al , appear to represent the first set of self-consistent cross sections for electron impact scattering from NO.

Electron impact fragmentation of thymine: partial ionization cross sections for positive fragments

NASA Astrophysics Data System (ADS)

van der Burgt, Peter J. M.; Mahon, Francis; Barrett, Gerard; Gradziel, Marcin L.

2014-06-01

We have measured mass spectra for positive ions for low-energy electron impact on thymine using a reflectron time-of-flight mass spectrometer. Using computer controlled data acquisition, mass spectra have been acquired for electron impact energies up to 100 eV in steps of 0.5 eV. Ion yield curves for most of the fragment ions have been determined by fitting groups of adjacent peaks in the mass spectra with sequences of normalized Gaussians. The ion yield curves have been normalized by comparing the sum of the ion yields to the average of calculated total ionization cross sections. Appearance energies have been determined. The nearly equal appearance energies of 83 u and 55 u observed in the present work strongly indicate that near threshold the 55 u ion is formed directly by the breakage of two bonds in the ring, rather than from a successive loss of HNCO and CO from the parent ion. Likewise 54 u is not formed by CO loss from 82 u. The appearance energies are in a number of cases consistent with the loss of one or more hydrogen atoms from a heavier fragment, but 70 u is not formed by hydrogen loss from 71 u.

Piezoelectrically-induced trap-depth reduction model of elastico-mechanoluminescent materials

NASA Astrophysics Data System (ADS)

Chandra, B. P.; Chandra, V. K.; Jha, Piyush

2015-03-01

Considering the detrapping of charge carriers due to reduction in trap-depth caused by piezoelectric field produced by applied pressure, an expression is derived for the detrapping rate of electrons. Then, an expression is obtained for the rate of generation of excited ions produced during capture of detrapped electrons by Eu3+ ions in persistent luminescent materials or by the energy released during electron-hole recombination in ZnS:Mn crystals. Finally, an expression is explored for the elastico-mechanoluminescence (EML) intensity, which is able to explain satisfactorily the characteristics of EML for the application of static pressure as well as for impact pressure. The total number of detrapped electrons and the total EML intensity are found to increase linearly with the electrostatic energy of the crystals in piezoelectric field. It is shown that the EML intensity should increase with the EML efficiency, number of crystallites (volume of sample), concentration of local piezoelectric regions in crystallites, piezoelectric constant of local piezoelectric regions, average length of the local piezoelectric regions, total number of electron traps, pressing rate, and applied pressure, and it should be higher for the materials having low value of threshold pressure and low value of trap-depth in unstressed condition. On the basis of the piezoelectrically-induced trap-depth reduction model of EML reported in the present investigation novel intense elastico mechanoluminescent materials having repetitive EML with undiminished intensity for successive loadings can be tailored which may find applications in sensing, imaging, lighting, colored displays, and other mechano-optical devices.

Electron- and proton-induced ionization of pyrimidine

DOE PAGES

Champion, Christophe; Quinto, Michele; Weck, Philippe F

2015-03-27

This present work describes a quantum-mechanically based model of the electron- and proton-induced ionization of isolated pyrimidine molecules. The impact energies range from the target ionization threshold up to ~1 keV for electrons and from 10 keV up to 10 MeV for protons. The cross-section calculations are performed within the 1st Born approximation in which the ejected electron is described by a Coulomb wave whereas the incident and the scattered projectiles are both described by plane waves. The pyrimidine target is described using the Gaussian 09 software package. Furthermore, our theoretical predictions obtained are in good agreement with experimental absolutemore » total cross sections, while large discrepancies are observed between existing semi-empirical models and the present calculations.« less

Electronic media use and sleep in school-aged children and adolescents: A review.

PubMed

Cain, Neralie; Gradisar, Michael

2010-09-01

Electronic media have often been considered to have a negative impact on the sleep of children and adolescents, but there are no comprehensive reviews of research in this area. The present study identified 36 papers that have investigated the relationship between sleep and electronic media in school-aged children and adolescents, including television viewing, use of computers, electronic gaming, and/or the internet, mobile telephones, and music. Many variables have been investigated across these studies, although delayed bedtime and shorter total sleep time have been found to be most consistently related to media use. A model of the mechanisms by which media use may affect sleep is presented and discussed as a vehicle for future research. Copyright 2010 Elsevier B.V. All rights reserved.

College of Business Faculty Views on Gift Authorships in Business Journals

ERIC Educational Resources Information Center

Manton, Edgar J.; English, Donald E.; Brodnax, Thomas

2012-01-01

The views of college of business faculty were sought to determine their perception on the extent of undeserved authorship in business journals and their impact on the faculty reward system. Six hundred ninety-eight faculty members responded to an electronic survey conducted through Zoomerang. A total of 80% of the respondents indicated that they…

Microscopic analysis of homogeneous electron gas by considering dipole-dipole interaction

NASA Astrophysics Data System (ADS)

Bordbar, G. H.; Pouresmaeeli, F.

2017-12-01

Implying perturbation theory, the impact of the dipole-dipole interaction (DDI) on the thermodynamic properties of a homogeneous electron gas at zero temperature is investigated. Through the second quantization formalism, the analytic expressions for the ground state energy and the DDI energy are obtained. In this paper, the DDI energy has similarities with the previous works done by others. We show that its general behavior depends on density and the total angular momentum. Especially, it is found that the DDI energy has a highly state-dependent behavior. With the growth of density, the magnitude of DDI energy, which is found to be the summation of all energy contributions of the states with even and odd total angular momenta, grows linearly. It is also found that for the states with even and odd total angular momenta, the DDI energy contributions are corresponding to the positive and negative values, respectively. In particular, an increase of total angular momentum leads to decline in the magnitude of energy contribution. Therefore, the dipole-dipole interaction reveals distinct characteristics in comparison with central-like interactions.

Pseudostate methods and differential cross sections for antiproton ionization of atomic hydrogen and helium

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGovern, M.; Walters, H. R. J.; Assafrao, D.

2010-03-15

A relaxed form of a recent impact parameter coupled pseudostate approximation of McGovern et al. [Phys. Rev. A 79, 042707 (2009)] for calculating differential ionization cross sections is proposed. This greatly eases the computational burden in cases where a range of ejected electron energies has to be considered. The relaxed approximation is tested against exact first Born calculations for antiproton impact on H and nonperturbatively for the highly nonperturbative system of Au{sup 53+} incident upon He. The approximation performs well in these tests. It is shown how, with a little further approximation, the relaxed theory leads to a widely usedmore » prescription for the total ionization cross section. Results for differential ionization of H and He by antiprotons are presented. These reveal the growing dominance of the interaction between the antiproton and the target nucleus at low impact energies and show the changing importance of the role of the postcollisional interaction between the antiproton and the ejected electron.« less

On the Utilization of In-flight Radiation-induced Performance Data and Anomaly Resolution of Commercial Off the Shelf (COTS) Electronics

NASA Technical Reports Server (NTRS)

LeBel, Kenneth A.; Poivey, Christian; Barth, Janet L.

2003-01-01

This viewgraph presentation presents an overview of the use of in-flight science data to review the radiation effects on commercial off the shelf (COTS) electronics used in recent spacecraft missions. The authors review the hazards that the space radiation environment pose for spacecraft electronics. They specifically discuss long term effects such as total ionizing dose (TID) and short term effects like single particle events (SEE). The advantages of using COTS electronics despite not being radiation hardened are mentioned. The reasons cite for tracking in-flight performance of COTS electronics include: anomaly resolution, validate ground tests and environmental predictions and provide lessons for future designers. Sample radiation impacts of science data from the following missions are analyzed: SOHO/LASCO 3 Coronograph, Microwave Anisotrophy Probe, Hubble Space Telescope and Chandra X-Ray Observatory.

Academic Impact of a Public Electronic Health Database: Bibliometric Analysis of Studies Using the General Practice Research Database

PubMed Central

Chen, Yu-Chun; Wu, Jau-Ching; Haschler, Ingo; Majeed, Azeem; Chen, Tzeng-Ji; Wetter, Thomas

2011-01-01

Background Studies that use electronic health databases as research material are getting popular but the influence of a single electronic health database had not been well investigated yet. The United Kingdom's General Practice Research Database (GPRD) is one of the few electronic health databases publicly available to academic researchers. This study analyzed studies that used GPRD to demonstrate the scientific production and academic impact by a single public health database. Methodology and Findings A total of 749 studies published between 1995 and 2009 with ‘General Practice Research Database’ as their topics, defined as GPRD studies, were extracted from Web of Science. By the end of 2009, the GPRD had attracted 1251 authors from 22 countries and been used extensively in 749 studies published in 193 journals across 58 study fields. Each GPRD study was cited 2.7 times by successive studies. Moreover, the total number of GPRD studies increased rapidly, and it is expected to reach 1500 by 2015, twice the number accumulated till the end of 2009. Since 17 of the most prolific authors (1.4% of all authors) contributed nearly half (47.9%) of GPRD studies, success in conducting GPRD studies may accumulate. The GPRD was used mainly in, but not limited to, the three study fields of “Pharmacology and Pharmacy”, “General and Internal Medicine”, and “Public, Environmental and Occupational Health”. The UK and United States were the two most active regions of GPRD studies. One-third of GRPD studies were internationally co-authored. Conclusions A public electronic health database such as the GPRD will promote scientific production in many ways. Data owners of electronic health databases at a national level should consider how to reduce access barriers and to make data more available for research. PMID:21731733

Single ionization and capture cross sections from biological molecules by bare projectile impact*

NASA Astrophysics Data System (ADS)

Quinto, Michele A.; Monti, Juan M.; Montenegro, Pablo D.; Fojón, Omar A.; Champion, Christophe; Rivarola, Roberto D.

2017-02-01

We report calculations on single differential and total cross sections for single ionization and single electron capture from biological targets, namely, vapor water and DNA nucleobasese molecules, by bare projectile impact: H+, He2+, and C6+. They are performed within the Continuum Distorted Wave - Eikonal Initial State approximation and compared to several existing experimental data. This study is oriented to the obtention of a reliable set of theoretical data to be used as input in a Monte Carlo code destined to micro- and nano- dosimetry.

Differential electron emission from polycyclic aromatic hydrocarbon molecules under fast ion impact

DOE PAGES

Biswas, Shubhadeep; Champion, Christophe; Weck, P. F.; ...

2017-07-17

Interaction between polycyclic aromatic hydrocarbon (PAH) molecule and energetic ion is a subject of interest in different areas of modern physics. Here, we present measurements of energy and angular distributions of absolute double differential electron emission cross section for coronene (C 24H 12) and fluorene (C 13H 10) molecules under fast bare oxygen ion impact. For coronene, the angular distributions of the low energy electrons are quite different from that of simpler targets like Ne or CH 4, which is not the case for fluorene. The behaviour of the higher electron energy distributions for both the targets are similar tomore » that for simple targets. In case of coronene, a clear signature of plasmon resonance is observed in the analysis of forward-backward angular asymmetry of low energy electron emission. For fluorene, such signature is not identified probably due to lower oscillator strength of plasmon compared to the coronene. The theoretical calculation based on the first-order Born approximation with correct boundary conditions (CB1), in general, reproduced the experimental observations qualitatively, for both the molecules, except in the low energy region for coronene, which again indicates the role of collective excitation. Single differential and total cross sections are also deduced. An overall comparative study is presented.« less

Copper fine-structure K-shell electron impact ionization cross sections for fast-electron diagnostic in laser-solid experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmeri, P., E-mail: patrick.palmeri@umons.ac.be; Quinet, P., E-mail: pascal.quinet@umons.ac.be; IPNAS, Université de Liège, B-4000 Liège

2015-03-15

The K-shell electron impact ionization (EII) cross section, along with the K-shell fluorescence yield, is one of the key atomic parameters for fast-electron diagnostic in laser-solid experiments through the K-shell emission cross section. In addition, copper is a material that has been often used in those experiments because it has a maximum total K-shell emission yield. Furthermore, in a campaign dedicated to the modeling of the K lines of astrophysical interest (Palmeri et al., 2012), the K-shell fluorescence yields for the K-vacancy fine-structure atomic levels of all the copper isonuclear ions have been calculated. In this study, the K-shell EII crossmore » sections connecting the ground and the metastable levels of the parent copper ions to the daughter ions K-vacancy levels considered in Palmeri et al. (2012) have been determined. The relativistic distorted-wave (DW) approximation implemented in the FAC atomic code has been used for the incident electron kinetic energies up to 10 times the K-shell threshold energies. Moreover, the resulting DW cross sections have been extrapolated at higher energies using the asymptotic form proposed by Davies et al. (2013)« less

Enhanced laser-energy coupling to dense plasmas driven by recirculating electron currents

NASA Astrophysics Data System (ADS)

Gray, R. J.; Wilson, R.; King, M.; Williamson, S. D. R.; Dance, R. J.; Armstrong, C.; Brabetz, C.; Wagner, F.; Zielbauer, B.; Bagnoud, V.; Neely, D.; McKenna, P.

2018-03-01

The absorption of laser energy and dynamics of energetic electrons in dense plasma is fundamental to a range of intense laser-driven particle and radiation generation mechanisms. We measure the total reflected and scattered laser energy as a function of intensity, distinguishing between the influence of pulse energy and focal spot size on total energy absorption, in the interaction with thin foils. We confirm a previously published scaling of absorption with intensity by variation of laser pulse energy, but find a slower scaling when changing the focal spot size. 2D particle-in-cell simulations show that the measured differences arise due to energetic electrons recirculating within the target and undergoing multiple interactions with the laser pulse, which enhances absorption in the case of large focal spots. This effect is also shown to be dependent on the laser pulse duration, the target thickness and the electron beam divergence. The parameter space over which this absorption enhancement occurs is explored via an analytical model. The results impact our understanding of the fundamental physics of laser energy absorption in solids and thus the development of particle and radiation sources driven by intense laser–solid interactions.

Advanced risk assessment of the effects of graphite fibers on electronic and electric equipment

NASA Technical Reports Server (NTRS)

Pocinki, L.; Cornell, M.; Kaplan, L.

1980-01-01

An assessment of the risk associated with accidents involving aircraft with carbon fiber composite structural components is examined. The individual fiber segments cause electrical and electronic equipment to fail under certain operating conditions. A Monte Carlo simulation model was used to computer the risk. Aircraft accidents with fire, release of carbon fiber material, entrainment of carbon fibers in a smoke plume transport of fibers downwind, transfer of some fibers/into the the interior of buildings, failures of electrical and electronic equipment, and economic impact of failures are discussed. Risk profiles were prepared for individual airports and the Nation. The vulnerability of electrical transmission equipment to carbon fiber incursion and aircraft accident total costs is investigated.

Electron-Impact Excitation of Ions Effects of Presence of Another Ion

NASA Astrophysics Data System (ADS)

Ohsaki, Akihiko; Nagasaki, Satoshi; Uramoto, Sei-iti; Takayanagi, Kazuo

2000-02-01

Present work gives for the first time the formulation of the two-center Coulomb-Born approximation (TCCBA) and presents some calculations for the electron-impact excitations in electron-ion-ion systems.The effect of the third body was relatively small in the cases studied so far. However, if the third body is a bare ion with a charge larger than the target ion, there will be a marked influence of the three-body collisions.Utilizing TCCBA we present the total and partial cross sections of hydrogen-like ions He+(Z=2), and C5+(Z=6) in the hydrogen plasma from the ground states 1s to the excited states 2s and 2p0, 2p± for the collision energies from 0.4Z2 to 2Z2 a.u.; for the excited states of the target ions, Stark effect is also studied.It is found that the presence of another ion have little effect on the 1s-2s transition and the 2s-2p Stark mixing has a prominent effect.

Calculations of total electron-impact ionization cross sections for Fluoroketone C5F10O and Fluoronitrile C4F7N using modified Deutsch-Märk formula

NASA Astrophysics Data System (ADS)

Xiong, Jiayu; Li, Xingwen; Wu, Jian; Guo, Xiaoxue; Zhao, Hu

2017-11-01

Both fluoroketone C5F10O and fluoronitrile C4F7N are promising substitute gases for SF6. The electron-impact ionization cross sections for these two gases are calculated using the Deutsch-Märk (DM) formula and its modified method. The necessary molecular geometry optimization and electron population were determined by ab initio calculation, which was performed with quantum chemistry code. The level of calculation, including the theoretical method and basis-set, are carefully determined. To eliminate the drawbacks of the DM formula, a modified DM formula is set in this paper. The modified DM formula, of which the weighting factors are changed, has a better agreement with the experimental data on both the peak and shape of the cross-section curves. The results calculated by DM formula and modified DM formula are given as references to fill in gaps in further research into C5F10O and C4F7N.

Near-threshold electron-impact doubly differential cross sections for the ionization of argon and krypton

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yates, Brent R.; Khakoo, Murtadha A.

2011-04-15

We present normalized doubly differential cross sections (DDCS's) for the near-threshold, electron-impact single ionization of argon and krypton, similar to those taken earlier for Ne and Xe [Yates et al., J. Phys. B 42, 095206 (2009)]. The Ar measurements were taken at incident energies of 17, 18, 20, and 30 eV while the Kr measurements were taken at 15, 16, 17.5, and 20 eV. The DDCS scattering angles range from 15 deg. to 120 deg. The differential data are initially normalized to available experimental cross sections for excitation of the ground np{sup 6} to the np{sup 5}(n+1)s excited states ofmore » the noble gas and, after integration, to well-established experimental total ionization cross sections of Rapp and Englander-Golden [J. Chem. Phys. 43, 1464 (1965)].« less

Electron-impact ionization cross sections out of the ground and 6P2 excited states of cesium

NASA Astrophysics Data System (ADS)

Łukomski, M.; Sutton, S.; Kedzierski, W.; Reddish, T. J.; Bartschat, K.; Bartlett, P. L.; Bray, I.; Stelbovics, A. T.; McConkey, J. W.

2006-09-01

An atom trapping technique for determining absolute, total ionization cross sections (TICS) out of an excited atom is presented. The unique feature of our method is in utilizing Doppler cooling of neutral atoms to determine ionization cross sections. This fluorescence-monitoring experiment, which is a variant of the “trap loss” technique, has enabled us to obtain the experimental electron impact ionization cross sections out of the Cs 6P3/22 state between 7eV and 400eV . CCC, RMPS, and Born theoretical results are also presented for both the ground and excited states of cesium and rubidium. In the low energy region (<11eV) where best agreement between these excited state measurements and theory might be expected, a discrepancy of approximately a factor of five is observed. Above this energy there are significant contributions to the TICS from both autoionization and multiple ionization.

Measurements of Excitation Functions and Line Polarizations for Electron Impact Excitation of the n = 2, 3 States of Atomic Hydrogen in the Energy Range 11 - 2000 eV

NASA Technical Reports Server (NTRS)

James, G. K.; Ajello, J. M.; Kanik, I.; Slevin, J.; Franklin, B.; Shemansky, D.

1993-01-01

The electron-atomic hydrogen scattering system is an important testing ground for theoretical models and has received a great deal of attention from experimentalists and theoreticians alike over the years. A complete description of the excitation process requires a knowledge of many different parameters, and experimental measurements of these parameters have been performed in various laboratories around the world. As far as total cross section data are concerned it has been noted that the discrepancy between the data of Long et al. and Williams for n = 2 excitations needs to be resolved in the interests of any further refinement of theory. We report new measurements of total cross sections and atomic line polarizations for both n=2 and n=3 excitations at energies from threshold to 2000 eV...

The Role of Information Provision in Economic Evaluations of Newborn Bloodspot Screening: A Systematic Review.

PubMed

Wright, Stuart J; Jones, Cheryl; Payne, Katherine; Dharni, Nimarta; Ulph, Fiona

2015-12-01

The extent to which economic evaluations have included the healthcare resource and outcome-related implications of information provision in national newborn bloodspot screening programmes (NBSPs) is not currently known. To identify if, and how, information provision has been incorporated into published economic evaluations of NBSPs. A systematic review of economic evaluations of NBSPs (up to November 2014) was conducted. Three electronic databases were searched (Ovid: Medline, Embase, CINAHL) using an electronic search strategy combining a published economic search filter with terms related to national NBSPs and screening-related technologies. These electronic searches were supplemented by searching the NHS Economic Evaluations Database (NHS EED) and hand-searching identified study reference lists. The results were tabulated and summarised as part of a narrative synthesis. A total of 27 economic evaluations [screening-related technologies (n = 11) and NBSPs (n = 16)] were identified. The majority of economic evaluations did not quantify the impact of information provision in terms of healthcare costs or outcomes. Five studies did include an estimate of the time cost associated with information provision. Four studies included a value to reflect the disutility associated with parental anxiety caused by false-positive results, which was used as a proxy for the impact of imperfect information. A limited evidence base currently quantifies the impact of information provision on the healthcare costs and impact on the users of NBSPs; the parents of newborns. We suggest that economic evaluations of expanded NBSPs need to take account of information provision otherwise the impact on healthcare costs and the outcomes for newborns and their parents may be underestimated.

A preliminary report on the study of the impact sites and particles of the solar maximum satellite thermal blanket

NASA Technical Reports Server (NTRS)

Zook, H. A.

1985-01-01

A preliminary study of the work on examination of the impact pits in, or penetrations through, the thermal blankets of the Solar Maximum Satellite is presented. The three largest pieces of the thermal blanket were optically scanned with a total surface area of about one half square meter. Over 1500 impact sites of all sizes, including 432 impacts larger than 40 microns in diameter, have been documented. Craters larger in diameter than about 100 microns found on the 75 micron thick Kapton first sheet of the main electronics box blanket are actually holes and constitute perforations through the blanket. A summary of the impact pit population that were found is given. The chemical study of these craters is only in the initial stages, with only about 250 chemical spectra of particles observed in or around impact pits or in the debris pattern being recorded.

A search for shocked quartz grains in the Allerød-Younger Dryas boundary layer

NASA Astrophysics Data System (ADS)

Hoesel, Annelies; Hoek, Wim Z.; Pennock, Gillian M.; Kaiser, Knut; Plümper, Oliver; Jankowski, Michal; Hamers, Maartje F.; Schlaak, Norbert; Küster, Mathias; Andronikov, Alexander V.; Drury, Martyn R.

2015-03-01

The Younger Dryas impact hypothesis suggests that multiple airbursts or extraterrestrial impacts occurring at the end of the Allerød interstadial resulted in the Younger Dryas cold period. So far, no reproducible, diagnostic evidence has, however, been reported. Quartz grains containing planar deformation features (known as shocked quartz grains), are considered a reliable indicator for the occurrence of an extraterrestrial impact when found in a geological setting. Although alleged shocked quartz grains have been reported at a possible Allerød-Younger Dryas boundary layer in Venezuela, the identification of shocked quartz in this layer is ambiguous. To test whether shocked quartz is indeed present in the proposed impact layer, we investigated the quartz fraction of multiple Allerød-Younger Dryas boundary layers from Europe and North America, where proposed impact markers have been reported. Grains were analyzed using a combination of light and electron microscopy techniques. All samples contained a variable amount of quartz grains with (sub)planar microstructures, often tectonic deformation lamellae. A total of one quartz grain containing planar deformation features was found in our samples. This shocked quartz grain comes from the Usselo palaeosol at Geldrop Aalsterhut, the Netherlands. Scanning electron microscopy cathodoluminescence imaging and transmission electron microscopy imaging, however, show that the planar deformation features in this grain are healed and thus likely to be older than the Allerød-Younger Dryas boundary. We suggest that this grain was possibly eroded from an older crater or distal ejecta layer and later redeposited in the European sandbelt. The single shocked quartz grain at this moment thus cannot be used to support the Younger Dryas impact hypothesis.

Using electronic technology to improve clinical care - results from a before-after cluster trial to evaluate assessment and classification of sick children according to Integrated Management of Childhood Illness (IMCI) protocol in Tanzania.

PubMed

Mitchell, Marc; Hedt-Gauthier, Bethany L; Msellemu, Daniel; Nkaka, Melania; Lesh, Neal

2013-08-27

Poor adherence to the Integrated Management of Childhood Illness (IMCI) protocol reduces the potential impact on under-five morbidity and mortality. Electronic technology could improve adherence; however there are few studies demonstrating the benefits of such technology in a resource-poor settings. This study estimates the impact of electronic technology on adherence to the IMCI protocols as compared to the current paper-based protocols in Tanzania. In four districts in Tanzania, 18 clinics were randomly selected for inclusion. At each site, observers documented critical parts of the clinical assessment of children aged 2 months to 5 years. The first set of observations occurred during examination of children using paper-based IMCI (pIMCI) and the next set of observations occurred during examination using the electronic IMCI (eIMCI). Children were re-examined by an IMCI expert and the diagnoses were compared. A total of 1221 children (671 paper, 550 electronic) were observed. For all ten critical IMCI items included in both systems, adherence to the protocol was greater for eIMCI than for pIMCI. The proportion assessed under pIMCI ranged from 61% to 98% compared to 92% to 100% under eIMCI (p < 0.05 for each of the ten assessment items). Use of electronic systems improved the completeness of assessment of children with acute illness in Tanzania. With the before-after nature of the design, potential for temporal confounding is the primary limitation. However, the data collection for both phases occurred over a short period (one month) and so temporal confounding was expected to be minimal. The results suggest that the use of electronic IMCI protocols can improve the completeness and consistency of clinical assessments and future studies will examine the long-term health and health systems impact of eIMCI.

Inductively coupled Cl2/Ar plasma: Experimental investigation and modeling

NASA Astrophysics Data System (ADS)

Efremov, A. M.; Kim, Dong-Pyo; Kim, Chang-Il

2003-07-01

Electrophysical and kinetic characteristics of Cl2/Ar plasma were investigated to understand the influence of the addition of Ar on the volume densities and fluxes of active particles, both neutral and charged. Our analysis combined both experimental methods and plasma modeling. It was found that addition of Ar to Cl2 leads to deformation of the electron energy distribution function and an increase of the electron mean energy due to the ``transparency'' effect. Direct electron impact dissociation of Cl2 molecules represents the main source of chlorine atoms in the plasma volume. The contributions of stepwise dissociation and ionization involving Ar metastable atoms were found to be negligible. Addition of Ar to Cl2 causes the decrease of both electron and ion densities due to a decrease in the total ionization rate and the acceleration of heterogeneous decay of charged particles.

Cross sections for ionization of tetrahydrofuran by protons at energies between 300 and 3000 keV

NASA Astrophysics Data System (ADS)

Wang, Mingjie; Rudek, Benedikt; Bennett, Daniel; de Vera, Pablo; Bug, Marion; Buhr, Ticia; Baek, Woon Yong; Hilgers, Gerhard; Rabus, Hans

2016-05-01

Double-differential cross sections for ionization of tetrahydrofuran by protons with energies from 300 to 3000 keV were measured at the Physikalisch-Technische Bundesanstalt ion accelerator facility. The electrons emitted at angles between 15∘ and 150∘ relative to the ion-beam direction were detected with an electrostatic hemispherical electron spectrometer. Single-differential and total ionization cross sections have been derived by integration. The experimental results are compared to the semiempirical Hansen-Kocbach-Stolterfoht model as well as to the recently reported method based on the dielectric formalism. The comparison to the latter showed good agreement with experimental data in a broad range of emission angles and energies of secondary electrons. The scaling property of ionization cross sections for tetrahydrofuran was also investigated. Compared to molecules of different size, the ionization cross sections of tetrahydrofuran were found to scale with the number of valence electrons at large impact parameters.

Electron- and proton-induced ionization of pyrimidine

NASA Astrophysics Data System (ADS)

Champion, Christophe; Quinto, Michele A.; Weck, Philippe F.

2015-05-01

The present work describes a quantum-mechanically based model of the electron- and proton-induced ionization of isolated pyrimidine molecules. The impact energies range from the target ionization threshold up to ~1 keV for electrons and from 10 keV up to 10 MeV for protons. The cross-section calculations are performed within the 1st Born approximation in which the ejected electron is described by a Coulomb wave whereas the incident and the scattered projectiles are both described by plane waves. The pyrimidine target is described using the Gaussian 09 software package. The theoretical predictions obtained are in good agreement with experimental absolute total cross sections, while large discrepancies are observed between existing semi-empirical models and the present calculations. Contribution to the Topical Issue "COST Action Nano-IBCT: Nano-scale Processes Behind Ion-Beam Cancer Therapy", edited by Andrey Solov'yov, Nigel Mason, Gustavo García, Eugene Surdutovich.

Electron and positron interaction with pyrimidine: A theoretical investigation

NASA Astrophysics Data System (ADS)

Sinha, Nidhi; Antony, Bobby

2018-03-01

Pyrimidine (C4H4N2) is considered as the building block of nucleobases, viz., cytosine, thymine and uracil. They provide a blueprint for probing the scattering of radiation by DNA and RNA bases. In this article, we report the elastic and total scattering cross-sections for electron and positron scattering from the pyrimidine molecule, employing a spherical complex optical potential (SCOP) formalism for an extensive energy range of 10 eV to 5 keV. In the case of positron scattering, the original SCOP formalism is modified to adequately solve the positron-target dynamics. Moreover, a reasonable agreement is observed between the present results and other available datasets, for both electron and positron scattering. The cross-sections for electron and positron impact scattering by pyrimidine are necessary input data for codes that seek to simulate radiation damage, and hence are useful to model biomolecular systems.

Does long time spending on the electronic devices affect the reading abilities? A cross-sectional study among Chinese school-aged children.

PubMed

He, Zhen; Shao, Shanshan; Zhou, Jie; Ke, Juntao; Kong, Rui; Guo, Shengnan; Zhang, Jiajia; Song, Ranran

2014-12-01

Home literacy environment (HLE) is one of most important modifiable risk factors to dyslexia. With the development in technology, we include the electronic devices usage at home, such as computers and televisions, to the definition of HLE and investigate its impact on dyslexia based on the on-going project of Tongji's Reading Environment and Dyslexia Study. The data include 5063 children, primary school students (grade 3-grade 6), from a middle-sized city in China. We apply the principal component analysis (PCA) to reduce the large dimension of variables in HLE, and find the first three components, denoted as PC1, PC2 and PC3, can explain 95.45% of HLE information. PC1 and PC2 demonstrate strong positive association with 'total time spending on electronic devices' and 'literacy-related activity', respectively. PC3 demonstrates strong negative association with 'restrictions on using electronic devices'. From the generalized linear model, we find that PC1 significantly increases the risk of dyslexia (OR = 1.043, 95% CI: 1.018-1.070), while PC2 significantly decreases the risk of dyslexia (OR = 0.839, 95% CI: 0.795-0.886). Therefore, reducing the total time spending on electronic devices and increasing the literacy-related activity would be the potential protective factors for dyslexic children in China. Copyright © 2014 Elsevier Ltd. All rights reserved.

Time-dependent spin-density-functional-theory description of He+-He collisions

NASA Astrophysics Data System (ADS)

Baxter, Matthew; Kirchner, Tom; Engel, Eberhard

2017-09-01

Theoretical total cross-section results for all ionization and capture processes in the He+-He collision system are presented in the approximate impact energy range of 10-1000 keV/amu. Calculations were performed within the framework of time-dependent spin-density functional theory. The Krieger-Li-Iafrate approximation was used to determine an accurate exchange-correlation potential in the exchange-only limit. The results of two models, one where electron translation factors in the orbitals used to calculate the potential are ignored and another where partial electron translation factors are included, are compared with available experimental data as well as a selection of previous theoretical calculations.

Use of household supermarket sales data to estimate nutrient intakes: a comparison with repeat 24-hour dietary recalls.

PubMed

Eyles, Helen; Jiang, Yannan; Ni Mhurchu, Cliona

2010-01-01

Electronic supermarket sales data provide a promising, novel way of estimating nutrient intakes. However, little is known about how these data reflect the nutrients consumed by an individual household member. A cross-sectional survey of 49 primary household shoppers (age [mean+/-standard deviation age]=48+/-14 years; 84% female) from Wellington, New Zealand, was undertaken. Three months of baseline electronic supermarket sales data were compared with individual dietary intakes estimated from four random 24-hour dietary recalls collected during the same 3-month period. Spearman rank correlations between household purchases and individual intakes ranged from 0.54 for percentage of energy from saturated fat (P<0.001) to 0.06 for sodium (P=0.68). Other correlation coefficients were: percentage of energy from carbohydrate, 0.48; and protein, 0.44; energy density of nonbeverages, 0.37 (kcal/oz); percentage of energy from total fat, 0.34; sugar, 0.33 (oz/kcal); and energy density of beverages, 0.09 (oz/kcal; all P values <0.05). This research suggests that household electronic supermarket sales data may be a useful surrogate measure of some nutrient intakes of individuals, particularly percentage of energy from saturated and total fat. In the case of a supermarket intervention, an effect on household sales of percentage energy from saturated and total fat is also likely to impact the saturated and total fat intake of individual household members. Copyright 2010 American Dietetic Association. Published by Elsevier Inc. All rights reserved.

The Impact of an Integrated Electronic Health Record Adoption on Nursing Care Quality.

PubMed

Walker-Czyz, AnneMarie

2016-01-01

The purpose of this study was to measure the impact of an integrated electronic health record (EHR) innovation adoption on the quality of nursing care delivered, including hospital-acquired falls, hospital-acquired pressure ulcers, ventilator-associated pneumonia (VAP), central line-associated bloodstream infections (CLABSIs), catheter-associated urinary tract infections (CAUTIs), and costs measured in nursing hours. The impact on quality, cost, and nurse satisfaction measured in turnover rates before, during, and after implementation of EHR tools was also investigated. Little is known about the adoption patterns of computerized documentation by nursing and the effects on the practice environment. A quantitative, retrospective analysis using interrupted time series model of a large data set was conducted in a 431-bed urban hospital, with 10 medical surgical units and 2 critical care units. The research was constructed using the Diffusion of Innovations (DOI) theory. Incorporating electronic, evidenced-based practice (EBP) tools into bedside nurse's workflow promotes decision making at the point of care that may improve quality with no negative impact on direct cost. The data revealed that total falls, CAUTI, and CLABSI rates were positively impacted after the implementation of an integrated EHR. Hospital-acquired pressure ulcer and VAP rates were negatively impacted at the implementation period followed by a significant positive rate reduction that surpassed the preimplementation period. Cost indicators, measured in hours per patient day and overtime, were negatively impacted during the implementation period followed by a return to baseline. Nurse turnover had a significant increase from the preimplementation to postimplementation period and failed to return to baseline. This study confirms that nurses have the ability to positively impact the quality of patient care through successful innovation adoption related to the use of EBP computerized documentation tools at the bedside. This study further clarified the practice environment of nurses during DOI.

Effect of the sample annealing temperature and sample crystallographic orientation on the charge kinetics of MgO single crystals subjected to keV electron irradiation.

PubMed

Boughariou, A; Damamme, G; Kallel, A

2015-04-01

This paper focuses on the effect of sample annealing temperature and crystallographic orientation on the secondary electron yield of MgO during charging by a defocused electron beam irradiation. The experimental results show that there are two regimes during the charging process that are better identified by plotting the logarithm of the secondary electron emission yield, lnσ, as function of the total trapped charge in the material QT. The impact of the annealing temperature and crystallographic orientation on the evolution of lnσ is presented here. The slope of the asymptotic regime of the curve lnσ as function of QT, expressed in cm(2) per trapped charge, is probably linked to the elementary cross section of electron-hole recombination, σhole, which controls the trapping evolution in the reach of the stationary flow regime. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

Electron scattering at interfaces in nano-scale vertical interconnects: A combined experimental and ab initio study

NASA Astrophysics Data System (ADS)

Lanzillo, Nicholas A.; Restrepo, Oscar D.; Bhosale, Prasad S.; Cruz-Silva, Eduardo; Yang, Chih-Chao; Youp Kim, Byoung; Spooner, Terry; Standaert, Theodorus; Child, Craig; Bonilla, Griselda; Murali, Kota V. R. M.

2018-04-01

We present a combined theoretical and experimental study on the electron transport characteristics across several representative interface structures found in back-end-of-line interconnect stacks for advanced semiconductor manufacturing: Cu/Ta(N)/Co/Cu and Cu/Ta(N)/Ru/Cu. In particular, we evaluate the impact of replacing a thin TaN barrier with Ta while considering both Co and Ru as wetting layers. Both theory and experiment indicate a pronounced reduction in vertical resistance when replacing TaN with Ta, regardless of whether a Co or Ru wetting layer is used. This indicates that a significant portion of the total vertical resistance is determined by electron scattering at the Cu/Ta(N) interface. The electronic structure of these nano-sized interconnects is analyzed in terms of the atom-resolved projected density of states and k-resolved transmission spectra at the Fermi level. This work further develops a fundamental understanding of electron transport and material characteristics in nano-sized interconnects.

Experimental and theoretical electron-scattering cross-section data for dichloromethane

NASA Astrophysics Data System (ADS)

Krupa, K.; Lange, E.; Blanco, F.; Barbosa, A. S.; Pastega, D. F.; Sanchez, S. d'A.; Bettega, M. H. F.; García, G.; Limão-Vieira, P.; Ferreira da Silva, F.

2018-04-01

We report on a combination of experimental and theoretical investigations into the elastic differential cross sections (DCSs) and integral cross sections for electron interactions with dichloromethane, C H2C l2 , in the incident electron energy over the 7.0-30 eV range. Elastic electron-scattering cross-section calculations have been performed within the framework of the Schwinger multichannel method implemented with pseudopotentials (SMCPP), and the independent-atom model with screening-corrected additivity rule including interference-effects correction (IAM-SCAR+I). The present elastic DCSs have been found to agree reasonably well with the results of IAM-SCAR+I calculations above 20 eV and also with the SMC calculations below 30 eV. Although some discrepancies were found for 7 eV, the agreement between the two theoretical methodologies is remarkable as the electron-impact energy increases. Calculated elastic DCSs are also reported up to 10000 eV for scattering angles from 0° to 180° together with total cross section within the IAM-SCAR+I framework.

Design of an electron projection system with slider lenses and multiple beams

NASA Astrophysics Data System (ADS)

Moonen, Daniel; Leunissen, Peter L. H. A.; de Jager, Patrick W.; Kruit, Pieter; Bleeker, Arno J.; Van der Mast, Karel D.

2002-07-01

The commercial applicability of electron beam projection lithography systems may be limited at high resolution because of low throughput. The main limitations to the throughput are: (i) Beam current. The Coulomb interaction between electrons result in an image blue. Therefore less beam current can be allowed at higher resolution, impacting the illuminate time of the wafer. (ii) Exposure field size. Early attempts to improve throughput with 'full chip' electron beam projection systems failed, because the system suffered from large off-axis aberrations of the electron optics, which severely restricted the useful field size. This has impact on the overhead time. A new type of projection optics will be proposed in this paper to overcome both limits. A slider lens is proposed that allows an effective field that is much larger than schemes proposed by SCALPEL and PREVAIL. The full width of the die can be exposed without mechanical scanning by sliding the beam through the slit-like bore of the lens. Locally, at the beam position, a 'round'-lens field is created with a combination of a rectangular magnetic field and quadruples that are positioned inside the lens. A die can now be exposed during a single mechanical scan as in state-of-the-art light optical tools. The total beam current can be improved without impact on the Coulomb interaction blur by combining several beams in a single lithography system if these beams do not interfere with each other. Several optical layouts have been proposed that combined up to 5 beams in a projection system consisting of a doublet of slider lenses. This type of projection optics has a potential throughput of 50 WPH at 45 nm with a resist sensitivity of 6 (mu) C/cm2.

One-dimensional multispecies hydrodynamic models of the wakeside ionosphere of Titan

NASA Technical Reports Server (NTRS)

Keller, C. N.; Cravens, T. E.

1994-01-01

The passage of Voyager 1 through the wakeside region of Titan's ionosphere provided an interesting probe of this plasma environment. A one-dimensional multispecies hydrodynamic model was developed to study the wakeside ionosphere for radial distances ranging from 1.3 to 4.5 R(sub T) and included the ion species H2CN(+), C(sub n) H(sub m)(+), C2H5(+), CH5(+), H(+), H2(+), and H3(+). Plasma transport only along magnetic field lines was included. The only source of ion production was from electron impact ionization of Titan's atmosphere by radially streaming Saturnian magnetospheric electrons (i.e., the nightside wakeside ionosphere). We found that ion production rates due to hot (200 eV) magnetospheric electrons impacting Titan's neutral atmosphere along radial field lines were comparable to the dayside ion production rates due to solar EUV flux. The magnetic flux tube area was varied along with electron temperature, and the results were compared to the ion densities and velocities measured during the Voyager 1 encounter. We found outward ion flows of about (2 to 7 x 10(exp 6)/sq cm/s, resulting in a total ion loss from Titan into Saturn's magnetosphere of about (6 to 20) x 10(exp 24)/s.

0.2 to 10 keV electrons interacting with water ice: Radiolysis, sputtering, and sublimation

NASA Astrophysics Data System (ADS)

Galli, A.; Vorburger, A.; Wurz, P.; Pommerol, A.; Cerubini, R.; Jost, B.; Poch, O.; Tulej, M.; Thomas, N.

2018-06-01

We present new laboratory experiments investigating various water ice samples, ranging from thin ice films to porous thick ice layers, that are irradiated with electrons. The molecules leaving the ice are monitored with a pressure gauge and a mass spectrometer. Most particles released from the ice are H2 and O2, the observed ratio of 2:1 is consistent with H2O being radiolysed into H2 + 1/2 O2 upon irradiation. H2O2 is likely a minor contribution of radiolysis, amounting to 0.001 ± 0.001 of the total gas release from the ice sample. Neither the physical properties of the ice, nor the energy, nor the electron impact angle have any obvious effect on the relative abundances of the radiolysis products. The absolute sputtering yield (i.e., the ratio of produced O2 or destroyed H2O per impacting electron) increases with energy until a few 100 eV. For higher energies up to 10 keV the yield remains roughly constant, once the saturation dose of the ice is reached. This indicates that ongoing irradiation eventually releases the radiolysis products from the water ice even for penetration depths of several micrometers.

Evaluation of electronic prescription implementation in polymedicated users of Catalonia, Spain: a population-based longitudinal study

PubMed Central

Lizano-Díez, Irene; Modamio, Pilar; López-Calahorra, Pilar; Lastra, Cecilia F; Segú, Jose L; Gilabert-Perramon, Antoni; Mariño, Eduardo L

2014-01-01

Objectives To assess whether electronic prescribing is a comprehensive health management tool that may contribute to rational drug use, particularly in polymedicated patients receiving 16 or more medications in the public healthcare system in the Barcelona Health Region (BHR). Design 16 months of retrospective study followed by 12 months of prospective monitoring. Setting Primary healthcare in BHR, Catalonia, Spain. Participants All insured patients, especially those who are polymedicated in six basic health areas (BHA). Polymedicated patients were those with a consumption of ≥16 drugs/month. Interventions Monitoring demographic and consumption variables obtained from the records of prescriptions dispensed in pharmacies and charged to the public health system, as well as the resulting drug use indicators. Territorial variables related to implementation of electronic prescribing were also described and were obtained from the institutional data related to the deployment of the project. Main outcome measures Trend in drug use indicators (number of prescriptions per polymedicated user, total cost per polymedicated user and total cost per prescription) according to e-prescription implementation. Results There was a significant upward trend in the number of polymedicated users, number of prescriptions and total cost (p<0.05), which seemed independent from the implementation of electronic prescribing when comparing the preimplementation and postimplementation period. Prescriptions per user and cost per user showed a decrease between the preimplementation and postimplementation period, being significant in two BHAs (p<0.05). Conclusions Results suggest that after the implementation of electronic prescribing, the rationality of prescribing in polymedicated patients improved. In addition, this study provides a very valuable approach for future impact assessment. PMID:25377013

Circular polarization of X-ray radiation emitted by longitudinally polarized electron impact excitation: Under a screened Coulomb interaction

NASA Astrophysics Data System (ADS)

Chen, Zhan-Bin

2017-12-01

Longitudinally polarized electron impact excitation from the ground state 1s2 to the excited state 1s2l (l =s,p) levels of highly charged He-like Fe24+ ions in weakly coupled hot-dense plasmas is investigated using a fully relativistic distorted-wave method. The Debye-Hückel potential is used to describe the plasma screening. Benchmark results such as the total cross sections, the magnetic sublevels cross sections, and the circular polarizations of corresponding X-ray radiations are presented. For the excitation process, results show that the plasma screening has an effect in reducing both the total and magnetic sublevels cross sections. For the de-excitation process, it is found that while the plasma screening as a slightly effect on the circular polarizations of radiations for the 1 s 2 s 3S1 → 1 s21S0,1 s 2 p 3P2 → 1 s21S0 , and 1 s 2 p 1P1 → 1 s21S0 transition lines, it gives a substantial contribution for the same properties of the 1 s 2 p 3P1 → 1 s21S0 line.

Differential cross sections for ionizations of H and H2 by 75 keV proton impact

NASA Astrophysics Data System (ADS)

Igarashi, A.; Gulyás, L.

2018-02-01

We have calculated total, partial and fully differential cross sections (FDCSs) for ionizations of H and H2 by 75 keV proton impact within the framework of the continuum-distorted-wave-eikonal-initial-state (CDW-EIS) approximation. Applying the single active electron model, the interaction between the projectile and the target ion is taken into account in the impact parameter picture. Extension of the CDW-EIS model to the molecular target is performed using the two-effective center approximation. The obtained results are compared with those of experimental and other theoretical data when available. The agreements between the theories and the experimental data are generally reasonable except for some cases of the FDCSs.

Production and mechanical properties of Al-SiC metal matrix composites

NASA Astrophysics Data System (ADS)

Karvanis, K.; Fasnakis, D.; Maropoulos, A.; Papanikolaou, S.

2016-11-01

The usage of Al-SiC Metal Matrix Composites is constantly increasing in the last years due to their unique properties such as light weight, high strength, high specific modulus, high fatigue strength, high hardness and low density. Al-SiC composites of various carbide compositions were produced using a centrifugal casting machine. The mechanical properties, tensile and compression strength, hardness and drop-weight impact strength were studied in order to determine the optimum carbide % in the metal matrix composites. Scanning electron microscopy was used to study the microstructure-property correlation. It was observed that the tensile and the compressive strength of the composites increased as the proportion of silicon carbide became higher in the composites. Also with increasing proportion of silicon carbide in the composite, the material became harder and appeared to have smaller values for total displacement and total energy during impact testing.

Waveguide detuning caused by transverse magnetic fields on a simulated in-line 6 MV linac.

PubMed

St Aubin, J; Steciw, S; Fallone, B G

2010-09-01

Due to the close proximity of the linear accelerator (linac) to the magnetic resonance (MR) imager in linac-MR systems, it will be subjected to magnet fringe fields larger than the Earth's magnetic field of 5 x 10(-5) T. Even with passive or active shielding designed to reduce these fields, some magnitude of the magnetic field is still expected to intersect the linac, causing electron deflection and beam loss. This beam loss, resulting from magnetic fields that cannot be eliminated with shielding, can cause a detuning of the waveguide due to excessive heating. The detuning, if significant, could lead to an even further decrease in output above what would be expected strictly from electron deflections caused by an external magnetic field. Thus an investigation of detuning was performed through various simulations. According to the Lorentz force, the electrons will be deflected away from their straight course to the target, depositing energy as they impact the linac copper waveguide. The deposited energy would lead to a heating and deformation of the copper structure resulting in resonant frequency changes. PARMELA was used to determine the mean energy and fraction of total beam lost in each linac cavity. The energy deposited into the copper waveguide from the beam losses caused by transverse magnetic fields was calculated using the Monte Carlo program DOSRZnrc. From the total energy deposited, the rise in temperature and ultimately the deformation of the structure was estimated. The deformed structure was modeled using the finite element method program COMSOL MULTIPHYSICS to determine the change in cavity resonant frequency. The largest changes in resonant frequency were found in the first two accelerating cavities for each field strength investigated. This was caused by a high electron fluence impacting the waveguide inner structures coupled with their low kinetic energies. At each field strength investigated, the total change in accelerator frequency was less than a manufacturing tolerance of 10 kHz and is thus not expected to have a noticeable effect on accelerator performance. The amount of beam loss caused by magnetic fringe fields for a linac in a linac-MR system depends on the effectiveness of its magnetic shielding. Despite the best efforts to shield the linac from the magnetic fringe fields, some persistent magnetic field is expected which would result in electron beam loss. This investigation showed that the detuning of the waveguide caused by additional electron beam loss in persistent magnetic fields is not a concern.

Failure to review STAT clinical laboratory requests and its economical impact.

PubMed

Rodriguez-Borja, Enrique; Villalba-Martinez, Celia; Barba-Serrano, Esther; Carratala-Calvo, Arturo

2016-01-01

Failure to follow-up laboratory test results has been described as one of the major processes contributing to unsafe patient care. Currently, most of the laboratories do not know with certainty not only their rate of missed (or unreviewed) requests but the economical cost and impact that this issue implies. The aim of our study was to measure that rate and calculate the resulting costs. In January 2015, we checked in our Laboratory Information Management System (LIMS) for every emergency request from 1(st) July 2011 to 30(th) June 2014, if they had been reviewed by any allowed user or not. 319,064 requests were ordered during that period of time. Results were expressed as "ordered requests", "missed requests" and its percentage. Additionally, total cost of missed requests was calculated in euros (€). "Non-productive days" were theorised (as the days producing requests that were not reviewed) based on these results. 7924 requests (2.5%) were never reviewed by clinicians. This represented a total cost of 203,039 € and 27 "non-productive" days in three years. Significant differences between inpatients, outpatients and emergency department as well as different emergencies units were found after application of statistical analysis. In terms of resources, never reviewed or missed requests appear to be a not negligible problem for the clinical laboratory management. Electronic result delivery, with electronic endorsement to indicate follow-up of requests along with better systems of electronic requesting should be investigated as a way of improving patient outcomes and save unnecessary expenses.

Changes of the Electrical and Optical Character of Polyimide Films Due to Exposure to High Energy GEO-like Electrons and the Chemistry that Drives it

NASA Astrophysics Data System (ADS)

Hoffmann, R.; Cooper, R.; Ferguson, D.

As a result of the interaction between the spacecraft and its operational environment, the constituent materials begin to change. These changes are determined by a combination of: chemical reactions, contamination, and energy deposition. They can range in severity from negligible to total loss of the material. Virtually all properties of the material, the mechanical, optical/thermal, and electrical are altered in largely unknown ways from the pristine materials. This negatively impacts the ability of spacecraft operators to predict the behavior of a spacecraft as it ages its environment. For example, in the case of electrical conduction in polyimide, there is a three orders of magnitude decrease in the resistivity after only eight months of simulated GEO electron exposure. Optical changes in the material also dramatically impact the ability of ground based optical observations to identify and track both known and unknown spacecraft. We will be presenting work done within the Spacecraft Charging and Instrument Calibration Lab at AFRL/RVB to quantify the changes in total reflection, BRDF, and electrical conduction of aluminized polyimide film after simulated aging in a GEO-like electron environment. We correlate these data with the chemical structure of the film as determined by XPS and NMR. A deeper, predictive understanding of how materials change will not only increase the operational lifetime of space assets by providing more accurate data to operators, it will improve SSA by allowing ground based observers to more accurately deduce component materials and determine how long a spacecraft has been in orbit.

Solar-powered unmanned aerial vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reinhardt, K.C.; Lamp, T.R.; Geis, J.W.

1996-12-31

An analysis was performed to determine the impact of various power system components and mission requirements on the size of solar-powered high altitude long endurance (HALE)-type aircraft. The HALE unmanned aerial vehicle (UAV) has good potential for use in many military and civil applications. The primary power system components considered in this study were photovoltaic (PV) modules for power generation and regenerative fuel cells for energy storage. The impact of relevant component performance on UAV size and capability were considered; including PV module efficiency and mass, power electronics efficiency, and fuel cell specific energy. Mission parameters such as time ofmore » year, flight altitude, flight latitude, and payload mass and power were also varied to determine impact on UAV size. The aircraft analysis method used determines the required aircraft wing aspect ratio, wing area, and total mass based on maximum endurance or minimum required power calculations. The results indicate that the capacity of the energy storage system employed, fuel cells in this analysis, greatly impacts aircraft size, whereas the impact of PV module efficiency and mass is much less important. It was concluded that an energy storage specific energy (total system) of 250--500 Whr/kg is required to enable most useful missions, and that PV cells with efficiencies greater than {approximately} 12% are suitable for use.« less

Absorbed dose evaluation of Auger electron-emitting radionuclides: impact of input decay spectra on dose point kernels and S-values

NASA Astrophysics Data System (ADS)

Falzone, Nadia; Lee, Boon Q.; Fernández-Varea, José M.; Kartsonaki, Christiana; Stuchbery, Andrew E.; Kibédi, Tibor; Vallis, Katherine A.

2017-03-01

The aim of this study was to investigate the impact of decay data provided by the newly developed stochastic atomic relaxation model BrIccEmis on dose point kernels (DPKs - radial dose distribution around a unit point source) and S-values (absorbed dose per unit cumulated activity) of 14 Auger electron (AE) emitting radionuclides, namely 67Ga, 80mBr, 89Zr, 90Nb, 99mTc, 111In, 117mSn, 119Sb, 123I, 124I, 125I, 135La, 195mPt and 201Tl. Radiation spectra were based on the nuclear decay data from the medical internal radiation dose (MIRD) RADTABS program and the BrIccEmis code, assuming both an isolated-atom and condensed-phase approach. DPKs were simulated with the PENELOPE Monte Carlo (MC) code using event-by-event electron and photon transport. S-values for concentric spherical cells of various sizes were derived from these DPKs using appropriate geometric reduction factors. The number of Auger and Coster-Kronig (CK) electrons and x-ray photons released per nuclear decay (yield) from MIRD-RADTABS were consistently higher than those calculated using BrIccEmis. DPKs for the electron spectra from BrIccEmis were considerably different from MIRD-RADTABS in the first few hundred nanometres from a point source where most of the Auger electrons are stopped. S-values were, however, not significantly impacted as the differences in DPKs in the sub-micrometre dimension were quickly diminished in larger dimensions. Overestimation in the total AE energy output by MIRD-RADTABS leads to higher predicted energy deposition by AE emitting radionuclides, especially in the immediate vicinity of the decaying radionuclides. This should be taken into account when MIRD-RADTABS data are used to simulate biological damage at nanoscale dimensions.

Electron Impact Ionization Cross Sections in Rb and Cs.

NASA Astrophysics Data System (ADS)

Reddish, T. J.; Lukomski, M.; Sutton, S.; Kedzierski, W.; McConkey, J. W.; Bartschat, K.; Bartlett, P. L.; Stelbovics, A. T.; Bray, I.

2006-05-01

We present a new atom trapping technique for determining absolute, total ionisation cross sections (TICS) out of an excited atom. The novel feature of this method is in utilizing Doppler cooling of neutral atoms to determine ionisation cross sections. This fluorescence-monitoring experiment, which is a variant of the `trap loss' technique, has enabled us to obtain the experimental electron impact ionisation cross sections out of the Cs 6^2P3/2 excited state between 7 - 400 eV. New CCC, R-Matrix with Pseudo-States (RMPS), and Born approximation single ionisation cross sections (SICS) are also presented for both the ground and excited states of Cs and Rb, and compared with the available experimental data. The comparison of the results reveals the importance of the autoionisation and multiple ionisation contributions to the TICS. The autoionisation contribution appears to be substantial for ionisation out of the Cs 6^2P and Rb 5^2P excited states; ˜ 3-4 larger than the direct ionisation contribution predicted by CCC at ˜ 30-50 eV. This surprising result shows the importance of multi-electron processes in determining the ionisation cross sections of heavy alkali atoms.

Electron loss from hydrogen-like highly charged ions in collisions with electrons, protons and light atoms

NASA Astrophysics Data System (ADS)

Lyashchenko, K. N.; Andreev, O. Yu; Voitkiv, A. B.

2018-03-01

We consider electron loss from a hydrogen-like highly charged ion (HCI) in relativistic collisions with hydrogen and helium in the range of impact velocities v min ≤ v ≤ v max (v min and v max correspond to the threshold energy ε th for electron loss in collisions with a free electron and to ≈5 ε th, respectively) where any reliable data for loss cross sections are absent. In this range, where the loss process is characterized by large momentum transfers, we express it in terms of electron loss in collisions with equivelocity protons and electrons and explore by performing a detailed comparative study of these subprocesses. Our results, in particular, show that: (i) compared to equivelocity electrons protons are more effective in inducing electron loss, (ii) the relative effectiveness of electron projectiles grows with increase in the atomic number of a HCI, (iii) collisions with protons and electrons lead to a qualitatively different population of the final-state-electron momentum space and even when the total loss cross sections in these collisions become already equal the spectra of the outgoing electrons still remain quite different in almost the entire volume of the final-state-electron momentum space, (iv) in collisions with hydrogen and helium the contributions to the loss process from the interactions with the nucleus and the electron(s) of the atom could be rather well separated in a substantial part of the final-state-electron momentum space.

Ab initio simulations of the dynamic ion structure factor of warm dense lithium

DOE PAGES

Witte, B. B. L.; Shihab, M.; Glenzer, S. H.; ...

2017-04-06

Here, we present molecular dynamics simulations based on finite-temperature density functional theory that determine self-consistently the dynamic ion structure factor and the electronic form factor in lithium. Our comprehensive data set allows for the calculation of the dispersion relation for collective excitations, the calculation of the sound velocity, and the determination of the ion feature from the total electronic form factor and the ion structure factor. The results are compared with available experimental x-ray and neutron scattering data. Good agreement is found for both the liquid metal and warm dense matter domain. Finally, we study the impact of possible targetmore » inhomogeneities on x-ray scattering spectra.« less

Ab initio simulations of the dynamic ion structure factor of warm dense lithium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Witte, B. B. L.; Shihab, M.; Glenzer, S. H.

Here, we present molecular dynamics simulations based on finite-temperature density functional theory that determine self-consistently the dynamic ion structure factor and the electronic form factor in lithium. Our comprehensive data set allows for the calculation of the dispersion relation for collective excitations, the calculation of the sound velocity, and the determination of the ion feature from the total electronic form factor and the ion structure factor. The results are compared with available experimental x-ray and neutron scattering data. Good agreement is found for both the liquid metal and warm dense matter domain. Finally, we study the impact of possible targetmore » inhomogeneities on x-ray scattering spectra.« less

The impact of spherical symmetry assumption on radio occultation data inversion in the ionosphere: An assessment study

NASA Astrophysics Data System (ADS)

Shaikh, M. M.; Notarpietro, R.; Nava, B.

2014-02-01

'Onion-peeling' is a very common technique used to invert Radio Occultation (RO) data in the ionosphere. Because of the implicit assumption of spherical symmetry for the electron density (N(e)) distribution in the ionosphere, the standard Onion-peeling algorithm could give erroneous concentration values in the retrieved electron density profile. In particular, this happens when strong horizontal ionospheric electron density gradients are present, like for example in the Equatorial Ionization Anomaly (EIA) region during high solar activity periods. In this work, using simulated RO Total Electron Content (TEC) data computed by means of the NeQuick2 ionospheric electron density model and ideal RO geometries, we tried to formulate and evaluate an asymmetry level index for quasi-horizontal TEC observations. The asymmetry index is based on the electron density variation that a signal may experience along its path (satellite to satellite link) in a RO event and is strictly dependent on the occultation geometry (e.g. azimuth of the occultation plane). A very good correlation has been found between the asymmetry index and errors related to the inversion products, in particular those concerning the peak electron density NmF2 estimate and the Vertical TEC (VTEC) evaluation.

Variations of E-region total electron content and electron density profiles over high latitudes during winter solstice 2007 using radio occultation measurements

NASA Astrophysics Data System (ADS)

Agrawal, Kajli

The space weather phenomenon involves the Sun, interplanetary space and the Earth. Different space weather conditions have diverse effects on the various layers of the Earth's atmosphere Technological advancements have created a situation in which human civilization is not only dependent on resources from deep inside the Earth, but also on the upper atmosphere and outer space region. Therefore, it is essential to improve the understanding of the impacts of space weather conditions on the ionosphere. This research focuses on the variation of total electron content (TEC) and the electron density within the E-region of the ionosphere, which extends from 80-150 km above the surface of the Earth, using radio occultation measurements obtained by COSMIC satellites and using Ionospheric Data Assimilation Four-Dimensional algorithm (IDA4D) which is used to mitigate the effects of F-region in the E-region estimation (Bust, Garner, & Gaussiran, 2004). E-region TEC and the electron density estimation for geomagnetic latitude range of 45°--80°, geomagnetic longitude range of -180°--180° and 1800--0600 MLT (magnetic local time) are presented for two active and two quiet days during winter solstice 2007. Active and quiet days are identified based on the Kp index values. Some of the important findings are (1) E-region electron peak density is higher during active days than during quiet days, and (2) during both types of days, higher density values were found at the magnetic latitude of >60° early morning MLT. Prominent E-region features (TEC and electron density) were observed during most active days over the magnetic latitude range of 60°-70° at ~02:00 MLT.

Impact resistance and fractography in ultra high molecular weight polyethylenes.

PubMed

Puértolas, J A; Pascual, F J; Martínez-Morlanes, M J

2014-02-01

Highly crosslinked ultra high molecular weight polyethylenes (UHMWPE) stabilized by a remelting process or by the addition of an antioxidant are highly wear resistant and chemically stable. However, these polyethylenes currently used in total joint replacements suffer a loss of mechanical properties, especially in terms of fracture toughness. In this study we analyze the impact behavior of different polyethylenes using an instrumented double notch Izod test. The materials studied are three resins: GUR1050, GUR1020 with 0.1wt% of vitamin E, and MG003 with 0.1wt% of vitamin E. These resins were gamma irradiated at 90kGy, and pre and post-irradiation remelting processes were applied to GUR1050 for two different time periods. Microstructural data were determined by means of differential scanning calorimetry and transmission electron microscopy. Fractography carried out on the impact fracture surfaces and images obtained by scanning electron microscopy after etching indicated the existence of a fringe structure formed by consecutive ductile-brittle and brittle-ductile transitions, which is related to the appearance of discontinuities in the load-deflection curves. A correlation has been made of the macroscopic impact strength results and the molecular chain and microstructural characteristics of these aforementioned materials, with a view to designing future resins with improved impact resistance. The use of UHMWPE resins with low molecular weight or the application of a remelting treatment could contribute to obtain a better impact strength behavior. © 2013 Published by Elsevier Ltd.

Angular Distribution and Linear Polarization of X-ray Radiation Resulting from Electron Impact Excitation of Highly Charged Ions in Debye Plasmas

NASA Astrophysics Data System (ADS)

Chen, Zhanbin

2018-05-01

Plasma-screening effects on the 1s _{1/2} → 2l (l = s , p ) and 1s _{1/2} → 3d _{3/2} electron-impact excitation of highly charged ions are investigated, together with their subsequent radiative decay. The analysis is performed based on the multi-configuration Dirac-Fock method and the fully relativistic distorted-wave method incorporating the Debye-Hückel potential. To explore the nature of the effects, calculations are carried out based on detailed analyses of the integrated total and magnetic sublevel cross sections, the alignment parameters, the linear polarizations, and the angular distribution of the X-ray photoemission, as well as on corresponding data calculated in various Debye lengths/environments, taking the 2p _{3/2}→ 1s _{1/2} and 3d _{3/2}→ 1s _{1/2} characteristic lines of H-like Fe^{25+} ion as an example. The present results are compared with experimental data and other theoretical predictions where available.

Autoionizing resonances in electron-impact ionization of O5+ ions

NASA Astrophysics Data System (ADS)

Müller, A.; Teng, H.; Hofmann, G.; Phaneuf, R. A.; Salzborn, E.

2000-12-01

We report on a detailed experimental and theoretical study of electron-impact ionization of O5+ ions. A high-resolution scan measurement of the K-shell excitation threshold region has been performed with statistical uncertainties as low as 0.03%. At this level of precision a wealth of features in the cross section arising from indirect ionization processes becomes visible, and even interference of direct ionization with resonant-excitation/auto-double-ionization (READI) is clearly observed. The experimental results are compared with R-matrix calculations that include both direct and indirect processes in a unified way. Radiative damping of autoionizing Li-like states is found to be about 10-15 %. The calculations almost perfectly reproduce most of the experimental resonance features found in the present measurement including READI. They also agree with the direct-ionization converged close-coupling results of I. Bray [J. Phys. B 28, L247 (1995)] and the absolute total ionization cross section measurement of K. Rinn et al. [Phys. Rev. A 36, 595 (1987)].

Ping-pong modes and higher-periodicity multipactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kishek, R. A.

Multipactor is a vacuum discharge driven by secondary electron emission. Multiple period multipactors have long been known to exist but have been studied less extensively. In a period-n multipactor, electrons undergo multiple impacts in one rf period, with the synchronous phase alternating periodically between multiple values. A novel resonant form is proposed that combines one- and two-surface impacts within a single period, provided the total transit time is an odd number of rf half-periods and the product of secondary yields exceeds unity. For low fD products, the simplest such mode is shown to significantly increase the upper electric field boundarymore » of the multipacting region and lead to overlap of higher-order bands. The results agree nicely with 3-D particle-in-cell code simulations. An alternative, map-based method is introduced for analyzing higher-periodicity multipactor. Practical implications of the findings are discussed, including consequences for multipactor suppression strategies using a dc magnetic field.« less

The Giotto radio-science experiment

NASA Technical Reports Server (NTRS)

Edenhofer, P.; Bird, M. K.; Buschert, H.; Esposito, P. B.; Porsche, H.; Volland, H.

1986-01-01

The scientific objectives of the Giotto Radio Science Experiment (GRE) are to determine the columnar electron content of Comet Halley/s ionosphere and the cometary mass fluence from atmospheric drag by using the radio signals from Giotto during the Halley encounter. The radio science data (S and X-band Doppler and range measurements) will be collected at NASA/s deep-space 64 m tracking antenna at Tidbinbilla near Canberra, in Australia. In order to separate the effects of the terrestrial ionosphere and the interplanetary plasma, S-band Doppler measurements will also be taken at Tidbinbilla along the line-of-sight of Japan/s cometary probe Sakigake during the Giotto-Halley Encounter. The measurements of cometary electron content and mass fluence will be inverted to derive the spatial distribution of the electron and mass (dust and gas) density within Halley/s coma. The GRE is the only experiment on Giotto capable of measuring the low-energy (10 eV) electron bulk population of Halley/s ionosphere and the total cometary mass flow impacting upon the spacecraft.

Quantum-mechanical predictions of electron-induced ionization cross sections of DNA components

NASA Astrophysics Data System (ADS)

Champion, Christophe

2013-05-01

Ionization of biomolecules remains still today rarely investigated on both the experimental and the theoretical sides. In this context, the present work appears as one of the first quantum mechanical approaches providing a multi-differential description of the electron-induced ionization process of the main DNA components for impact energies ranging from the target ionization threshold up to about 10 keV. The cross section calculations are here performed within the 1st Born approximation framework in which the ejected electron is described by a Coulomb wave whereas the incident and the scattered electrons are both described by a plane wave. The biological targets of interest, namely, the DNA nucleobases and the sugar-phosphate backbone, are here described by means of the GAUSSIAN 09 system using the restricted Hartree-Fock method with geometry optimization. The theoretical predictions also obtained have shown a reasonable agreement with the experimental total ionization cross sections while huge discrepancies have been pointed out with existing theoretical models, mainly developed within a semi-classical framework.

Evaluating the impact of library user training programmes across Thames Valley Strategic Health Authority in the UK.

PubMed

Trinder, Valerie M; Fleet, Geoffrey E; Gray, Anne E

2007-03-01

This study was undertaken to provide evidence that library outreach projects in the NHS in the Thames Valley Strategic Health Authority area were effective and could justify continued funding. The object was to assess whether information literacy skills training taken up by health professionals impacts on their confidence and skills in using electronic sources of health information. A total of 487 health professionals taking up training on a voluntary basis were assessed by completing a self-assessment questionnaire prior to and after training to establish their information literacy skills and confidence levels. Of these, 223 trainees (46%) also returned 6-week follow-up questionnaires. Results showed that 464 trainees (95%) intended to apply what they had learnt in a variety of ways; use of specific resources greatly increased after training and confidence in using them increased substantially. Use of search techniques increased considerably overall, whereas use of Google decreased. The major findings of this research are that training health-care personnel in the use of electronic resources impacts positively on their information literacy skills and confidence, and that the information available to them is considered to have potential value across health-care practice.

Ionization balance in Titan's nightside ionosphere

NASA Astrophysics Data System (ADS)

Vigren, E.; Galand, M.; Yelle, R. V.; Wellbrock, A.; Coates, A. J.; Snowden, D.; Cui, J.; Lavvas, P.; Edberg, N. J. T.; Shebanits, O.; Wahlund, J.-E.; Vuitton, V.; Mandt, K.

2015-03-01

Based on a multi-instrumental Cassini dataset we make model versus observation comparisons of plasma number densities, nP = (nenI)1/2 (ne and nI being the electron number density and total positive ion number density, respectively) and short-lived ion number densities (N+, CH2+, CH3+, CH4+) in the southern hemisphere of Titan's nightside ionosphere over altitudes ranging from 1100 and 1200 km and from 1100 to 1350 km, respectively. The nP model assumes photochemical equilibrium, ion-electron pair production driven by magnetospheric electron precipitation and dissociative recombination as the principal plasma neutralization process. The model to derive short-lived-ion number densities assumes photochemical equilibrium for the short-lived ions, primary ion production by electron-impact ionization of N2 and CH4 and removal of the short-lived ions through reactions with CH4. It is shown that the models reasonably reproduce the observations, both with regards to nP and the number densities of the short-lived ions. This is contrasted by the difficulties in accurately reproducing ion and electron number densities in Titan's sunlit ionosphere.

Ion Densities in the Nightside Ionosphere of Mars: Effects of Electron Impact Ionization

NASA Astrophysics Data System (ADS)

Girazian, Z.; Mahaffy, P.; Lillis, R. J.; Benna, M.; Elrod, M.; Fowler, C. M.; Mitchell, D. L.

2017-11-01

We use observations from the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission to show how superthermal electron fluxes and crustal magnetic fields affect ion densities in the nightside ionosphere of Mars. We find that due to electron impact ionization, high electron fluxes significantly increase the CO2+, O+, and O2+ densities below 200 km but only modestly increase the NO+ density. High electron fluxes also produce distinct peaks in the CO2+, O+, and O2+ altitude profiles. We also find that superthermal electron fluxes are smaller near strong crustal magnetic fields. Consequently, nightside ion densities are also smaller near strong crustal fields because they decay without being replenished by electron impact ionization. Furthermore, the NO+/O2+ ratio is enhanced near strong crustal fields because, in the absence of electron impact ionization, O2+ is converted into NO+ and not replenished. Our results show that electron impact ionization is a significant source of CO2+, O+, and O2+ in the nightside ionosphere of Mars.

Electron-impact vibrational excitation of the hydroxyl radical in the nighttime upper atmosphere

NASA Astrophysics Data System (ADS)

Campbell, Laurence; Brunger, Michael J.

2018-02-01

Chemical processes produce vibrationally excited hydroxyl (OH) in a layer centred at an altitude of about 87 km in the Earth's atmosphere. Observations of this layer are used to deduce temperatures in the mesosphere and to observe the passage of atmospheric gravity waves. Due to the low densities and energies at night of electrons at the relevant altitude, it is not expected that electron-impact excitation of OH would be significant. However, there are unexplained characteristics of OH densities and radiative emissions that might be explained by electron impact. These are measurements of higher than expected densities of OH above 90 km and of emissions at higher energies that cannot be explained by the chemical production processes. This study simulates the role of electron impact in these processes, using theoretical cross sections for electron-impact excitation of OH. The simulations show that electron impact, even in a substantial aurora, cannot fully explain these phenomena. However, in the process of this investigation, apparent inconsistencies in the theoretical cross sections and reaction rates were found, indicating that measurements of electron-impact excitation of OH are needed to resolve these problems and scale the theoretical predictions to allow more accurate simulations.

Vital sign documentation in electronic records: The development of workarounds.

PubMed

Stevenson, Jean E; Israelsson, Johan; Nilsson, Gunilla; Petersson, Goran; Bath, Peter A

2018-06-01

Workarounds are commonplace in healthcare settings. An increase in the use of electronic health records has led to an escalation of workarounds as healthcare professionals cope with systems which are inadequate for their needs. Closely related to this, the documentation of vital signs in electronic health records has been problematic. The accuracy and completeness of vital sign documentation has a direct impact on the recognition of deterioration in a patient's condition. We examined workflow processes to identify workarounds related to vital signs in a 372-bed hospital in Sweden. In three clinical areas, a qualitative study was performed with data collected during observations and interviews and analysed through thematic content analysis. We identified paper workarounds in the form of handwritten notes and a total of eight pre-printed paper observation charts. Our results suggested that nurses created workarounds to allow a smooth workflow and ensure patients safety.

Metastable Oxygen Production by Electron-Impact of Oxygen

NASA Astrophysics Data System (ADS)

Hein, Jeffrey; Johnson, Paul; Kanik, Isik; Malone, Charles

2014-05-01

Electron-impact excitation processes involving atomic and molecular oxygen are important in atmospheric interactions. The production of long-lived metastable O(1S) and O(1D) through electron impact of atomic O and molecular O2 play a significant role in the dynamics of oxygen-containing atmospheres (Earth, Europa, Io). Emissions from metastable O (1S --> 1D) produce the well-recognized green light from terrestrial aurora. Electron-impact excitation to 1S and 1D are sensitive channels for determining energy partitioning and dynamics from space weather. Electron-impact excitation cross sections determined through fundamental experimental studies are necessary for modeling of natural phenomena and observation data. The detection of metastable states in laboratory experiments requires a novel approach, since typical detection techniques (e.g., fluorescence by radiative de-excitation) cannot be performed due to the long-lived nature of the excited species. In this work, metastable O is produced through electron impact, and is incident on a cryogenically cooled rare gas matrix. The excimer production and subsequent rapid radiative de-excitation provides measurable signal that is directly related to the originating electron-impact excitation process.

Demand management: an audit of chemical pathology test rejections by an electronic gate-keeping system at an academic hospital in Cape Town.

PubMed

Smit, Ida; Zemlin, Annalise E; Erasmus, Rajiv T

2015-07-01

Demand management is an area of laboratory activity, which is becoming increasingly important. Within the health-care system, demand management can be defined as the use of health resources to maximise its utility. Tygerberg Hospital has introduced an electronic gate-keeping system. Chemistry tests which generate the highest cost are subjected to this system and may be automatically rejected according to a set of rules. This study aimed: (1) to identify the number of chemistry tests rejected by the eGK; (2) to identify which of these rejected tests were subsequently restored and (3) to assess the impact of rejections on clinical outcome and cost-saving. A retrospective audit was conducted to determine the number of chemistry tests rejected and subsequently restored over a 6-month period. The case-notes of patients for whom requested tests previously rejected had been restored were randomly selected and investigated to assess clinical impact. Any cost-saving was calculated. A total of 68,480 tests were subjected to gate-keeping, and 4605 tests (6.7%) were rejected while 679 (14.7%) of these were restored by the requestor phoning the laboratory after obtaining authorisation. After examining a subset of clinical notes it was found that in most cases (80%), patient care was unaffected. The total cost saved was £ 25,387. The majority of the rejected tests were unnecessary and following rejection, real savings were made. Electronic gate-keeping is a simple, effective and sustainable method of demand management. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Comparison of Ion Chemistries in Octafluoro-2-butene (2-C4F8) and in Octfluorocyclobutane (c-C4F8)

NASA Astrophysics Data System (ADS)

Jiao, Charles; Dejoseph, Charles; Garscadden, Alan

2007-10-01

2-C4F8 is one of the promising candidates to replace c-C4F8 that has been widely used for dielectric etching but is not environmentally friendly. In this study we have investigated electron impact ionization and ion-molecule reactions of 2-C4F8 using Fourier transform mass spectrometry (FTMS), and compared the results with those of c-C4F8 we have studied previously. Electron impact ionization of 2-C4F8 produces 15 ionic species including C4F7,8^+, C3F3,5,6^+, C2F4^+ and CF1-3^+ as the major ions. The total ionization cross section of 2-C4F8 reaches a maximum of 1.8x10-15 cm^2 at 90 eV. The ionization is dominated by the channel forming the parent ion C4F8^+ from 12 to 18 eV, and by the channel forming C3F5^+ from 18 to 70 eV. After 70 eV, CF3^+ becomes the dominant product ion. Among the major ions generated from the electron impact ionization of 2-C4F8, only CF^+, CF2^+ and CF3^+ are found to react with 2-C4F8, via F^- abstraction or charge transfer mechanism. The charge transfer reaction of Ar^++2-C4F8 produces primarily C4F7^+.

Commercial printing and electronic color printing

NASA Astrophysics Data System (ADS)

Webb, Joseph W.

1995-04-01

Technologies such as Xeikon, Indigo, and the Heidelberg/Presstek GTO-DI can change both the way print buyers may purchase printed material and the way printers and trade services respond to changing demands. Our recent study surveys the graphic arts industry for their current views of these new products and provides forecasts of installations and usage with breakdowns by market segment and size of firm. The acceptance of desktop publishing and electronic prepress have not only paved the way for a totally electronic printing process, but it has broadened the base of people who develop color originals for reproduction. Electronic printing adds the ability to customize jobs on the fly. How print providers will respond to the impact of electronic color printing depends on how each firm perceives the 'threat.' Most printing companies are run by entrepreneurial individuals who have, as their highest priority, their own economic survival. Service bureaus are already looking at electronic color printing as yet another way to differentiate their businesses. The study was based on a mail survey with 682 responses from graphic arts firms, interviews with printers, suppliers, associations and industry executives, and detailed secondary research. Results of a new survey in progress in January 1995 is also presented.

Resolving the role of femtosecond heated electrons in ultrafast spin dynamics.

PubMed

Mendil, J; Nieves, P; Chubykalo-Fesenko, O; Walowski, J; Santos, T; Pisana, S; Münzenberg, M

2014-02-05

Magnetization manipulation is essential for basic research and applications. A fundamental question is, how fast can the magnetization be reversed in nanoscale magnetic storage media. When subject to an ultrafast laser pulse, the speed of the magnetization dynamics depends on the nature of the energy transfer pathway. The order of the spin system can be effectively influenced through spin-flip processes mediated by hot electrons. It has been predicted that as electrons drive spins into the regime close to almost total demagnetization, characterized by a loss of ferromagnetic correlations near criticality, a second slower demagnetization process takes place after the initial fast drop of magnetization. By studying FePt, we unravel the fundamental role of the electronic structure. As the ferromagnet Fe becomes more noble in the FePt compound, the electronic structure is changed and the density of states around the Fermi level is reduced, thereby driving the spin correlations into the limit of critical fluctuations. We demonstrate the impact of the electrons and the ferromagnetic interactions, which allows a general insight into the mechanisms of spin dynamics when the ferromagnetic state is highly excited, and identifies possible recording speed limits in heat-assisted magnetization reversal.

Total cross sections of electron scattering by molecules NF3, PF3, N(CH3)3, P(CH3)3, NH(CH3)2, PH(CH3)2, NH2CH3 and PH2CH3 at 30-5000 eV

NASA Astrophysics Data System (ADS)

Shi, D. H.; Sun, J. F.; Zhu, Z. L.; Liu, Y. F.

2010-04-01

Total cross sections of electron scattering by eight molecules NF3, PF3, N(CH3)3, P(CH3)3, NH(CH3)2, PH(CH3)2, NH2CH3 and PH2CH3, which have some structural similarities, are calculated at the Hartree-Fork level by the modified additivity rule approach [D.H. Shi, J.F. Sun, Z.L. Zhu, H. Ma, Y.F. Liu, Eur. Phys. J. D 45, 253 (2007); D.H. Shi, J.F. Sun, Y.F. Liu, Z.L. Zhu, X.D. Yang, Chin. Opt. Lett. 4, 192 (2006)]. The modified additivity rule approach takes into considerations that the contributions of the geometric shielding effect vary as the energy of incident electrons, the dimension of target molecule, the number of electrons in the molecule and the number of atoms constituting the molecule. The present investigations cover the impact energy range from 30 to 5000 eV. The quantitative total cross sections are compared with those obtained by experiments and other theories. Excellent agreement is observed even at energies of several tens of eV. It shows that the modified additivity rule approach is applicable to carry out the total cross section calculations of electron scattering by these molecules at intermediate and high energies, in particular over the energy range above 80 eV or so. It proves that the microscopic molecular properties, such as the geometrical size of the target and the number of atoms constituting the molecule, are of crucial importance in the TCS calculations. The new results for PH(CH3)2 and PH2CH3 are also presented at energies from 30 to 5000 eV, although no experimental and theoretical data are available for comparison. In the present calculations, the atoms are still represented by the spherical complex optical potential, which is composed of static, exchange, polarization and absorption terms.

Ionization of biomolecular targets by ion impact: input data for radiobiological applications

NASA Astrophysics Data System (ADS)

de Vera, Pablo; Abril, Isabel; Garcia-Molina, Rafael; Solov'yov, Andrey V.

2013-06-01

In this work we review and further develop a semiempirical model recently proposed for the ion impact ionization of complex biological media. The model is based on the dielectric formalism, and makes use of a semiempirical parametrization of the optical energy-loss function of bioorganic compounds, allowing the calculation of single and total ionization cross sections and related quantities for condensed biological targets, such as liquid water, DNA and its components, proteins, lipids, carbohydrates or cell constituents. The model shows a very good agreement with experimental data for water, adenine and uracil, and allows the comparison of the ionization efficiency of different biological targets, and also the average kinetic energy of the ejected secondary electrons.

Upper stages utilizing electric propulsion

NASA Technical Reports Server (NTRS)

Byers, D. C.

1980-01-01

The payload characteristics of geocentric missions which utilize electron bombardment ion thruster systems are discussed. A baseline LEO to GEO orbit transfer mission was selected to describe the payload capabilities. The impacts on payloads of both mission parameters and electric propulsion technology options were evaluated. The characteristics of the electric propulsion thrust system and the power requirements were specified in order to predict payload mass. This was completed by utilizing a previously developed methodology which provides a detailed thrust system description after the final mass on orbit, the thrusting time, and the specific impulse are specified. The impact on payloads of total mass in LEO, thrusting time, propellant type, specific impulse, and power source characteristics was evaluated.

Evaluation of computational models and cross sections used by MCNP6 for simulation of characteristic X-ray emission from thick targets bombarded by kiloelectronvolt electrons

NASA Astrophysics Data System (ADS)

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 < 15 and overestimation of the Kα yield by more than 40% for the elements with 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 is of the order of the binding energy.

The Impact of Electronic Patient Portals on Patient Care: A Systematic Review of Controlled Trials

PubMed Central

Ammenwerth, Elske; Schnell-Inderst, Petra

2012-01-01

Background Modern information technology is changing and provides new challenges to health care. The emergence of the Internet and the electronic health record (EHR) has brought new opportunities for patients to play a more active role in his/her care. Although in many countries patients have the right to access their clinical information, access to clinical records electronically is not common. Patient portals consist of provider-tethered applications that allow patients to electronically access health information that are documented and managed by a health care institution. Although patient portals are already being implemented, it is still unclear in which ways these technologies can influence patient care. Objective To systematically review the available evidence on the impact of electronic patient portals on patient care. Methods A systematic search was conducted using PubMed and other sources to identify controlled experimental or quasi-experimental studies on the impact of patient portals that were published between 1990 and 2011. A total of 1,306 references from all the publication hits were screened, and 13 papers were retrieved for full text analysis. Results We identified 5 papers presenting 4 distinct studies. There were no statistically significant changes between intervention and control group in the 2 randomized controlled trials investigating the effect of patient portals on health outcomes. Significant changes in the patient portal group, compared to a control group, could be observed for the following parameters: quicker decrease in office visit rates and slower increase in telephone contacts; increase in number of messages sent; changes of the medication regimen; and better adherence to treatment. Conclusions The number of available controlled studies with regard to patient portals is low. Even when patient portals are often discussed as a way to empower patients and improve quality of care, there is insufficient evidence to support this assumption. PMID:23183044

Electron ionization of metastable nitrogen and oxygen atoms in relation to the auroral emissions

NASA Astrophysics Data System (ADS)

Pandya, Siddharth; Joshipura, K. N.

Atomic and molecular excited metastable states (EMS) are exotic systems due to their special properties like long radiative life-time, large size (average radius) and large polarizability along with relatively smaller first ionization energy compared to their respective ground states (GS). The present work includes our theoretical calculations on electron impact ionization of metastable atomic states N( (2) P), N( (2) D) of nitrogen and O( (1) S), O( (1) D) of oxygen. The targets of our present interest, are found to be present in our Earth's ionosphere and they play an important role in auroral emissions observed in Earth’s auroral regions [1] as also in the emissions observed from cometary coma [2, 3] and airglow emissions. In particular, atomic oxygen in EMS can radiate, the visible O( (1) D -> (3) P) doublet 6300 - 6364 Å red doublet, the O( (1) S -> (1) D) 5577 Å green line, and the ultraviolet O( (1) S -> (3) P) 2972 Å line. For metastable atomic nitrogen one observes the similar emissions, in different wavelengths, from (2) D and (2) P states. At the Earth's auroral altitudes, from where these emissions take place in the ionosphere, energetic electrons are also present. In particular, if the metastable N as well as O atoms are ionized by the impact of electrons then these species are no longer available for emissions. This is a possible loss mechanism, and hence it is necessary to analyze the importance of electron ionization of the EMS of atomic O and N, by calculating the relevant cross sections. In the present paper we investigate electron ionization of the said metastable species by calculating relevant total cross sections. Our quantum mechanical calculations are based on projected approximate ionization contribution in the total inelastic cross sections [4]. Detailed results and discussion along with the significance of these calculations will be presented during the COSPAR-2014. References [1] A.Bhardwaj, and G. R. Gladstone, Rev. Geophys., 38(3), 295-353 (2000) [2] A.Bhardwaj, and S. A. Haider, Adv. Space Res., 29(5), 745-750 (2002) [3] A. Bhardwaj and S. Raghuram, ApJ, 748:13 (2012) [4] S. H. Pandya et al.,Int. J. Mass Spectrom. 323-324, 28-33 (2012)

Musculoskeletal impact of the use of various types of electronic devices on university students in Hong Kong: An evaluation by means of self-reported questionnaire.

PubMed

Woo, Eugenia H C; White, Peter; Lai, Christopher W K

2016-12-01

Despite the increasingly widespread popularity of electronic devices, there are limited comprehensive studies on the effects of usage and exposure to multiple electronic devices over extended periods of time. Therefore, this study explored the cumulative musculoskeletal implications of exposure to various electronic devices among university students. A self-reported questionnaire was administered in the university in Hong Kong and students provided information about the frequency and duration of electronic devices use, including computers, mobile phones and game consoles, and reported on any musculoskeletal pain or discomfort that may relate to electronic devices usage in the immediate 12 months prior to the survey date. A total of 503 university students (59% males and 41% females) aged 18-25 years completed the questionnaire. The results showed that 251 (49.9%) respondents reported upper limb musculoskeletal symptoms, particularly in the neck and shoulder regions. Among these, 155 (61.8%) indicated that their discomfort was related to electronic device usage. Statistically significant differences in exposure to electronic devices and musculoskeletal outcomes between genders were found (p < 0.05). The use of electronic devices and habitual postures were associated with musculoskeletal problems among university students in Hong Kong. This phenomenon highlights the urgent need for ergonomics education and recommendations to increase students' awareness of musculoskeletal wellbeing. Copyright © 2016 Elsevier Ltd. All rights reserved.

Electron impact fragmentation of adenine: partial ionization cross sections for positive fragments

NASA Astrophysics Data System (ADS)

van der Burgt, Peter J. M.; Finnegan, Sinead; Eden, Samuel

2015-07-01

Using computer-controlled data acquisition we have measured mass spectra of positive ions for electron impact on adenine, with electron energies up to 100 eV. Ion yield curves for 50 ions have been obtained and normalized by comparing their sum to the average of calculated total ionization cross sections. Appearance energies have been determined for 37 ions; for 20 ions for the first time. All appearance energies are consistent with the fragmentation pathways identified in the literature. Second onset energies have been determined for 12 fragment ions (for 11 ions for the first time), indicating the occurrence of more than one fragmentation process e.g. for 39 u (C2HN+) and 70 u (C2H4N3+). Matching ion yield shapes (118-120 u, 107-108 u, 91-92 u, and 54-56 u) provide new evidence supporting closely related fragmentation pathways and are attributed to hydrogen rearrangement immediately preceding the fragmentation. We present the first measurement of the ion yield curve of the doubly charged parent ion (67.5 u), with an appearance energy of 23.5 ± 1.0 eV. Contribution to the Topical Issue "COST Action Nano-IBCT: Nano-scale Processes Behind Ion-Beam Cancer Therapy", edited by Andrey Solov'yov, Nigel Mason, Gustavo García, Eugene Surdutovich.

Investigations of the Nature and Behavior of Plasma-Density Disturbances That May Impact GPS and Other Transionospheric Systems

DTIC Science & Technology

2002-10-31

association with the High-frequency Active Auroral Research Program ( HAARP ). In addition to a classic riometer and a GPS Total Electron Content (TEC...sensor previously operating at the HAARP site, NWRA also operates a set of Transit receivers for measurements of TEC and scintillation at VHF and UHF...supplementing the receiver at HAARP with a receiver north of the site and an additional receiver installed south of the HAARP site.

Fever management in SAH.

PubMed

Scaravilli, V; Tinchero, G; Citerio, G

2011-09-01

An electronic literature search through August 2010 was performed to obtain articles describing fever incidence, impact, and treatment in patients with subarachnoid hemorrhage. A total of 24 original research studies evaluating fever in SAH were identified, with studies evaluating fever and outcome, temperature control strategies, and shivering. Fever during acute hospitalization for subarachnoid hemorrhage was consistently linked with worsened outcome and increased mortality. Antipyretic medications, surface cooling, and intravascular cooling may all reduce temperatures in patients with subarachnoid hemorrhage; however, benefits from cooling may be offset by negative consequences from shivering.

Does electronic health record use improve hospital financial performance? Evidence from panel data.

PubMed

Collum, Taleah H; Menachemi, Nir; Sen, Bisakha

2016-01-01

The aim of this study was to examine the impact of electronic health record (EHR) adoption on hospital financial performance. We constructed a longitudinal panel using data from the three secondary sources: (a) the 2007-2010 American Hospital Association (AHA) Annual Survey, (b) the 2007-2010 AHA Annual Survey Information Technology Supplement, and (c) the 2007-2011 Medicare Cost Reports from Centers for Medicare and Medicaid Services. Because potential financial benefits attributable to EHR adoption may take some time to accrue, we ran regressions with lags of 1 and 2 years that included hospital and year fixed effects to examine the relationship between the level of EHR adoption and three hospital financial performance measures. A change in the level of EHR adoption was not associated with changes in operating margin or return on assets within hospitals. However, total margin was significantly improved, after 2 years, in hospitals that moved from no EHR to having a comprehensive EHR in all areas of their hospital (β = 0.030, p < .034). On the other hand, hospitals that increased their level of EHR adoption but did not achieve hospital-wide comprehensive adoption did not experience changes in any financial performance measures examined. The improvements in total margin, as opposed to operating margin, are likely due to hospital incentive payments under the Health Information Technology for Economic and Clinical Health Act that are reflected in nonpatient revenues and therefore show up in total margin calculations. Thus, after 2 years of EHR adoption, hospital financial performance is observed to improve based only on meaningful use incentive payments. More research will be needed to determine whether EHR adoption impacts financial performance on a longer time horizon.

Electron impact excitation of coronene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khakoo, M.A.; Ratliff, J.M.; Trajmar, S.

1990-12-15

A preliminary study of the electron-impact excitation of thermally evaporated coronene at 550{degree} C was carried out using electron-energy-loss spectroscopy. Measurements of the energy-loss spectra of coronene at high (100 eV) and low (5--20 eV) impact energies are presented. One of the high-energy spectra was converted to an apparent generalized oscillator strength spectrum and compared to the photoabsorption spectrum of coronene. Observations concerning vibrational excitation of coronene by electron impact are also presented and discussed.

Design of Stretchable Electronics Against Impact.

PubMed

Yuan, J H; Pharr, M; Feng, X; Rogers, John A; Huang, Yonggang

2016-10-01

Stretchable electronics offer soft, biocompatible mechanical properties; these same properties make them susceptible to device failure associated with physical impact. This paper studies designs for stretchable electronics that resist failure from impacts due to incorporation of a viscoelastic encapsulation layer. Results indicate that the impact resistance depends on the thickness and viscoelastic properties of the encapsulation layer, as well as the duration of impact. An analytic model for the critical thickness of the encapsulation layer is established. It is shown that a commercially available, low modulus silicone material offers viscous properties that make it a good candidate as the encapsulation layer for stretchable electronics.

Estimate of the cost of multiple sclerosis in Spain by literature review.

PubMed

Fernández, Oscar; Calleja-Hernández, Miguel Angel; Meca-Lallana, José; Oreja-Guevara, Celia; Polanco, Ana; Pérez-Alcántara, Ferran

2017-08-01

Multiple Sclerosis (MS) is a progressive disease leading to increasing disability and costs. A literature review was carried out to identify MS costs and to estimate its economic burden in Spain. Areas Covered: The public electronic databases PubMed, ScienceDirect and IBECS were consulted and a manual review of communications presented at related congresses was carried out. A total of 225 references were obtained, of which 43 were finally included in the study. Expert Commentary: Three major cost groups were identified: direct healthcare costs, direct non-healthcare costs and indirect costs. There is a direct relationship between disease progression and increased costs, mainly direct non-healthcare costs (greater need for informal care) and indirect costs (greater loss of productivity). The total cost associated with MS in Spain is €1,395 million per year, and that the mean annual cost per patient is €30,050. Beyond costs, a large impact on the quality of life of patients, with an annual loss of up to 13,000 quality-adjusted life years was also estimated. MS has a large economic impact on Spanish society and a significant impact on the quality of life of patients.

Clinical implementation of total skin electron irradiation treatment with a 6 MeV electron beam in high-dose total skin electron mode

NASA Astrophysics Data System (ADS)

Lucero, J. F.; Rojas, J. I.

2016-07-01

Total skin electron irradiation (TSEI) is a special treatment technique offered by modern radiation oncology facilities, given for the treatment of mycosis fungoides, a rare skin disease, which is type of cutaneous T-cell lymphoma [1]. During treatment the patient's entire skin is irradiated with a uniform dose. The aim of this work is to present implementation of total skin electron irradiation treatment using IAEA TRS-398 code of practice for absolute dosimetry and taking advantage of the use of radiochromic films.

Clinical implementation of total skin electron irradiation treatment with a 6 MeV electron beam in high-dose total skin electron mode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lucero, J. F., E-mail: fernando.lucero@hoperadiotherapy.com.gt; Hope International, Guatemala; Rojas, J. I., E-mail: isaac.rojas@siglo21.cr

Total skin electron irradiation (TSEI) is a special treatment technique offered by modern radiation oncology facilities, given for the treatment of mycosis fungoides, a rare skin disease, which is type of cutaneous T-cell lymphoma [1]. During treatment the patient’s entire skin is irradiated with a uniform dose. The aim of this work is to present implementation of total skin electron irradiation treatment using IAEA TRS-398 code of practice for absolute dosimetry and taking advantage of the use of radiochromic films.

Design and performance of an instrument for electron impact tandem mass spectrometry and action spectroscopy of mass/charge selected macromolecular ions stored in RF ion trap*

NASA Astrophysics Data System (ADS)

Ranković, Milos Lj.; Giuliani, Alexandre; Milosavljević, Aleksandar R.

2016-06-01

A new apparatus was designed, coupling an electron gun with a linear quadrupole ion trap mass spectrometer, to perform m/ z (mass over charge) selected ion activation by electron impact for tandem mass spectrometry and action spectroscopy. We present in detail electron tracing simulations of a 300 eV electron beam inside the ion trap, design of the mechanical parts, electron optics and electronic circuits used in the experiment. We also report examples of electron impact activation tandem mass spectra for Ubiquitin protein, Substance P and Melittin peptides, at incident electron energies in the range from 280 eV to 300 eV.

Impact of Radiation Hardness and Operating Temperatures of Silicon Carbide Electronics on Space Power System Mass

NASA Technical Reports Server (NTRS)

Juhasz, Albert J.; Tew, Roy C.; Schwarze, Gene E.

1998-01-01

The effect of silicon carbide (SiC) electronics operating temperatures on Power Management and Distribution (PMAD), or Power Conditioning (PC), subsystem radiator size and mass requirements was evaluated for three power output levels (100 kW(e) , 1 MW(e), and 10 MW(e)) for near term technology ( i.e. 1500 K turbine inlet temperature) Closed Cycle Gas Turbine (CCGT) power systems with a High Temperature Gas Reactor (HTGR) heat source. The study was conducted for assumed PC radiator temperatures ranging from 370 to 845 K and for three scenarios of electrical energy to heat conversion levels which needed to be rejected to space by means of the PC radiator. In addition, during part of the study the radiation hardness of the PC electronics was varied at a fixed separation distance to estimate its effect on the mass of the instrument rated reactor shadow shield. With both the PC radiator and the conical shadow shield representing major components of the overall power system the influence of the above on total power system mass was also determined. As expected, results show that the greatest actual mass savings achieved by the use of SiC electronics occur with high capacity power systems. Moreover, raising the PC radiator temperature above 600 K yields only small additional system mass savings. The effect of increased radiation hardness on total system mass is to reduce system mass by virtue of lowering the shield mass.

Photon emission from massive projectile impacts on solids.

PubMed

Fernandez-Lima, F A; Pinnick, V T; Della-Negra, S; Schweikert, E A

2011-01-01

First evidence of photon emission from individual impacts of massive gold projectiles on solids for a number of projectile-target combinations is reported. Photon emission from individual impacts of massive Au(n) (+q) (1 ≤ n ≤ 400; q = 1-4) projectiles with impact energies in the range of 28-136 keV occurs in less than 10 ns after the projectile impact. Experimental observations show an increase in the photon yield from individual impacts with the projectile size and velocity. Concurrently with the photon emission, electron emission from the impact area has been observed below the kinetic emission threshold and under unlikely conditions for potential electron emission. We interpret the puzzling electron emission and correlated luminescence observation as evidence of the electronic excitation resulting from the high-energy density deposited by massive cluster projectiles during the impact.

Photon emission from massive projectile impacts on solids

PubMed Central

Fernandez-Lima, F. A.; Pinnick, V. T.; Della-Negra, S.; Schweikert, E. A.

2011-01-01

First evidence of photon emission from individual impacts of massive gold projectiles on solids for a number of projectile-target combinations is reported. Photon emission from individual impacts of massive Aun+q (1 ≤ n ≤ 400; q = 1–4) projectiles with impact energies in the range of 28–136 keV occurs in less than 10 ns after the projectile impact. Experimental observations show an increase in the photon yield from individual impacts with the projectile size and velocity. Concurrently with the photon emission, electron emission from the impact area has been observed below the kinetic emission threshold and under unlikely conditions for potential electron emission. We interpret the puzzling electron emission and correlated luminescence observation as evidence of the electronic excitation resulting from the high-energy density deposited by massive cluster projectiles during the impact. PMID:21603128

Electron-impact Ionization of P-like Ions Forming Si-like Ions

NASA Astrophysics Data System (ADS)

Kwon, D.-H.; Savin, D. W.

2014-03-01

We have calculated electron-impact ionization (EII) for P-like systems from P to Zn15 + forming Si-like ions. The work was performed using the flexible atomic code (FAC) which is based on a distorted-wave approximation. All 3l → nl' (n = 3-35) excitation-autoionization (EA) channels near the 3p direct ionization threshold and 2l → nl' (n = 3-10) EA channels at the higher energies are included. Close attention has been paid to the detailed branching ratios. Our calculated total EII cross sections are compared both with previous FAC calculations, which omitted many of these EA channels, and with the available experimental results. Moreover, for Fe11 +, we find that part of the remaining discrepancies between our calculations and recent measurements can be accounted for by the inclusion of the resonant excitation double autoionization process. Lastly, at the temperatures where each ion is predicted to peak in abundances in collisional ionization equilibrium, the Maxwellian rate coefficients derived from our calculations differ by 50%-7% from the previous FAC rate coefficients, with the difference decreasing with increasing charge.

Small-scale structure of O2(+) and proton hydrates in a Noctilucent Cloud and polar mesospheric summer echo of August 9/10 1991 above Kiruna

NASA Technical Reports Server (NTRS)

Balsiger, F.; Kopp, E.; Friedrich, M.; Torkar, K. M.; Walchli, U.

1993-01-01

A novel mass spectrometer designed to measure simultaneously positive ion composition in the mesosphere, was successfully launched during the NLC-91 project. Instruments supporting the mass spectrometer were a probed to measure both electrons and positive ions as well as a wave propagation experiment. The location of the Noctilucent Clouds (NLC) was determined by a particle impact sensor to detect secondary electrons and ions from the impact of NLC particle. The density of proton hydrates and of the related total ions is depleted in the NLC region at 83 km. An improved detection limit of 5 x 10(exp 4)/cu m for positive ions and improved height resolution revealed for the first time large gradients in the O2(+), H(+)(H2O)2 and H(+)(H2O)6 densities within a small height range of the order of 50 m. Such gradients at the altitude of NLC and Polar Mesospheric Summer Echoes (PMSE) are associated with strong variability of mesospheric water vapor, temperature and neutral air density.

How does feedback from patients impact upon healthcare student clinical skill development and learning? A systematic review.

PubMed

Finch, Emma; Lethlean, Jennifer; Rose, Tanya; Fleming, Jennifer; Theodoros, Deborah; Cameron, Ashley; Coleman, Adele; Copland, David; McPhail, Steven M

2018-03-01

A key feature of health professionals' training, irrespective of discipline, is the acquisition and application of clinical and communication skills. Despite this, little is known about the potential role of patient feedback on this process. This systematic review aimed to answer the question: How does feedback from patients impact upon healthcare student clinical skill development and learning? Systematic review of published literature. Electronic databases were searched for studies that explored the effects of patient feedback on student learning and were published before March 2016. Eligible articles underwent methodological evaluation using the McMaster University Critical Evaluation Forms and data extraction. A total of 237 articles were retrieved following searches of electronic databases and hand searches of reference lists. Twelve (7 quantitative, 2 qualitative, 3 mixed methods) studies met the inclusion criteria. Eleven studies reported that patient feedback improved students' clinical skills. Minimal research has explored the impact of patient feedback on student learning. The research to date suggests that direct feedback from patients may be beneficial for the development of students' communication and clinical skills; however, the wide variety of evaluation methods and the lack of validated tools for patients to provide feedback suggest that further exploration is warranted.

Development of Styrene-Grafted Polyurethane by Radiation-Based Techniques

PubMed Central

Jeong, Jin-Oh; Park, Jong-Seok; Lim, Youn-Mook

2016-01-01

Polyurethane (PU) is the fifth most common polymer in the general consumer market, following Polypropylene (PP), Polyethylene (PE), Polyvinyl chloride (PVC), and Polystyrene (PS), and the most common polymer for thermosetting resins. In particular, polyurethane has excellent hardness and heat resistance, is a widely used material for electronic products and automotive parts, and can be used to create products of various physical properties, including rigid and flexible foams, films, and fibers. However, the use of polar polymer polyurethane as an impact modifier of non-polar polymers is limited due to poor combustion resistance and impact resistance. In this study, we used gamma irradiation at 25 and 50 kGy to introduce the styrene of hydrophobic monomer on the polyurethane as an impact modifier of the non-polar polymer. To verify grafted styrene, we confirmed the phenyl group of styrene at 690 cm−1 by Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) and at 6.4–6.8 ppm by 1H-Nuclear Magnetic Resonance (1H-NMR). Scanning Electron Microscope (SEM), X-ray Photoelectron Spectroscopy (XPS), Thermogravimetric Analysis (TGA) and contact angle analysis were also used to confirm styrene introduction. This study has confirmed the possibility of applying high-functional composite through radiation-based techniques. PMID:28773561

Effects of electronic billboards on driver distraction.

PubMed

Dukic, Tania; Ahlstrom, Christer; Patten, Christopher; Kettwich, Carmen; Kircher, Katja

2013-01-01

There is an increase in electronic advertising billboards along major roads, which may cause driver distraction due to the highly conspicuous design of the electronic billboards. Yet limited research on the impact of electronic billboards on driving performance and driver behavior is available. The Swedish Transport Administration recently approved the installation of 12 electronic billboards for a trial period along a 3-lane motorway with heavy traffic running through central Stockholm, Sweden. The aim of this study was to evaluate the effect of these electronic billboards on visual behavior and driving performance. A total of 41 drivers were recruited to drive an instrumented vehicle passing 4 of the electronic billboards during day and night conditions. A driver was considered visually distracted when looking at a billboard continuously for more than 2 s or if the driver looked away from the road for a high percentage of time. Dependent variables were eye-tracking measures and driving performance measures. The visual behavior data showed that drivers had a significantly longer dwell time, a greater number of fixations, and longer maximum fixation duration when driving past an electronic billboard compared to other signs on the same road stretches. No differences were found for the factors day/night, and no effect was found for the driving behavior data. Electronic billboards have an effect on gaze behavior by attracting more and longer glances than regular traffic signs. Whether the electronic billboards attract too much attention and constitute a traffic safety hazard cannot be answered conclusively based on the present data.

Environmental impact and human exposure to PCBs in Guiyu, an electronic waste recycling site in China.

PubMed

Xing, Guan Hua; Chan, Janet Kit Yan; Leung, Anna Oi Wah; Wu, Sheng Chun; Wong, M H

2009-01-01

PCB levels in fish (collected from local rivers), atmosphere and human milk samples have been studied to determine the exposure levels of PCBs for local residents and e-waste workers in Guiyu, a major electronic waste scrapping center in China. The source appointment and correlation analyses showed that homologue composition of PCBs in 7 species of fish were consistent and similar to commercial PCBs Aroclor 1248. PCB levels in air surrounding the open burning site were significantly higher than those in residential area. Inhalation exposure contributed 27% and 93% to the total body loadings (the sum of dietary and inhalation exposure) of the local residents, and e-waste workers engaged in open burning respectively. Total PCB concentrations in human milk ranged from N.D. to 57.6 ng/g lipid, with an average of 9.50 ng/g lipid. The present results indicated that commercial PCBs derived from e-waste recycling are major sources of PCBs accumulating in different environmental media, leading to the accumulation of high chlorinated biphenyls in human beings.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Catoire, F.; Staicu-Casagrande, E. M.; Lahmam-Bennani, A.

We describe new developments aimed to extend the capabilities and the sensitivity of the (e,2e)/(e,3e) multicoincidence spectrometer at Orsay University [Duguet et al., Rev. Sci. Instrum. 69, 3524 (1998)]. The spectrometer has been improved by the addition of a third multiangle detection channel for the fast ''scattered'' electron. The present system is unique in that it is the only system which combines three toroidal analyzers all equipped with position sensitive detectors, thus allowing the triple coincidence detection of the three electrons present in the final state of an electron impact double ionization process. The setup allows measurement of the angularmore » and energy distributions of the ejected electrons over almost the totality of the collision plane as well as that of the scattered electron over a large range of scattering angles in the forward direction. The resulting gain in sensitivity ({approx}25) has rendered feasible a whole class of experiments which could not be otherwise envisaged. The setup is described with a special emphasis on the new toroidal analyzer, data acquisition hardware, and data analysis procedures. The performances are illustrated by selected results of (e,2e) and (e,3e) experiments on the rare gases.« less

Vibrational population of the A super 3 sigma sub u/+/ and B super 3 pi sub g states of N2 in normal auroras.

NASA Technical Reports Server (NTRS)

Cartwright, D. C.; Trajmar, S.; Williams, W.

1971-01-01

Use of new electron impact excitation cross sections for the six lowest triplet states (A, B, W, C, E, D) of N2, and solution of the coupled equations of statistical equilibrium to obtain the vibrational population of each electronic state. The results show that cascade from high levels of the A super 3 sigma sub u(+) state and from the W super 3 delta sub u state is significant in populating the lower vibrational levels of the B state and hence the character of its ?apparent' excitation cross sections. For the B state excited under auroral conditions, the fraction of the total population due to cascade processes exceeds 25% for all levels lower than 7 and is greater than 80% for B(v' = 0). For the A state under similar conditions, cascade from the B state contributes 50% or more of the total vibrational population for levels lower than 7, and 80% or more for levels below 4. For levels of the A state greater than 7, the A yields B transitions depopulate the levels rapidly and indicate that the Vegard-Kaplan emissions from these higher levels will be weak or totally absent in normal auroras.

Hiding the interior region of core-shell nanoparticles with quantum invisible cloaks

NASA Astrophysics Data System (ADS)

Lee, Jeng Yi; Lee, Ray-Kuang

2014-04-01

Based on the scattering cancellation, we provide a method not only making a nanoparticle nearly invisible, but also hiding its interior region from the outside probing matter wave. By applying the interplay among the nodal points of partial waves along with the concept of streamline in fluid dynamics for probability flux, a quantum invisible cloak to the electron transport in a host semiconductor is demonstrated by simultaneously guiding the probability flux outside a hidden region and keeping the total scattering cross section negligible. As the probability flux vanishes in the interior region, one can embed any materials inside a multiple core-shell nanoparticle without affecting physical observables from the outside. Our results reveal the possibility to design a protection shield layer for fragile interior parts from the impact of transport electrons.

Implementation of electronic locking devices for adolescents at German tobacco vending machines: intended and unintended changes of supply and demand.

PubMed

Schneider, S; Meyer, C; Yamamoto, S; Solle, D

2009-08-01

Starting from 1 January 2007, electronic locking devices based on proof-of-age (via electronic cash cards or a European driving licence) were installed in approximately 500,000 vending machines across Germany to restrict the purchase of cigarettes to those over the age of 16. To examine changes in the number of tobacco vending machines before and after the introduction of these new measures. The total number of commercial tobacco sources in 2 selected districts (70,000 inhabitants) in Cologne were recorded and mapped. This major German city was the ideal setting for this study as investigators were able to use existing sociogeographical data from the area. A complete inventory was compiled in autumn 2005 and 2007. A total of 780 students aged 12 to 15 were also interviewed in the study areas. The main outcome measures were quantities and locations of commercial tobacco sources. Between 2005 and 2007 the total number of tobacco sources decreased from 315 to 277 within the study area. Although the most obvious reduction was detected in the number of outdoor vending machines (-48%), the number of indoor vending machines also decreased by 8%. Adolescents changed from vending machines to other sources for cigarettes, particularly kiosks or friends (+31% points usage rate, p<0.001; +35% points usage rate, p<0.001, respectively). Although the number of tobacco vending machines decreased, this has not had a significant impact on cigarette acquisition by underage smokers as they were able to circumvent this new security measure in several different ways.

Mass Spectrometric and Langmuir Probe Measurements in Inductively Coupled Plasmas in Ar, CHF3/Ar and CHF3/Ar/O2 Mixtures

NASA Technical Reports Server (NTRS)

Kim, J. S.; Rao, M. V. V. S.; Cappelli, M. A.; Sharma, S. P.; Meyyappan, M.; Arnold, Jim (Technical Monitor)

2000-01-01

Absolute fluxes and energy distributions of ions in inductively coupled plasmas of Ar, CHF3/Ar, and CHF3/Ar/O2 have been measured. These plasmas were generated in a Gaseous Electronics Conference (GEC) cell modified for inductive coupling at pressures 10-50 mTorr and 100-300 W of 13.56 MHz radio frequency (RF) power in various feedgas mixtures. In pure Ar plasmas, the Ar(+) flux increases linearly with pressure as well as RF-power. Total ion flux in CHF3 mixtures decreases with increase in pressure and also CHF3 concentration. Relative ion fluxes observed in the present studies are analyzed with the help of available cross sections for electron impact ionization and charge-exchange ion-molecule reactions. Measurements of plasma potential, electron and ion number densities, electron energy distribution function, and mean electron energy have also been made in the center of the plasma with a RF compensated Langmuir probe. Plasma potential values are compared with the mean ion energies determined from the measured ion energy distributions and are consistent. Electron temperature, plasma potential, and mean ion energy vary inversely with pressure, but increase with CHF3 content in the mixture.

Metastable Oxygen Production by Electron-Impact of Oxygen

NASA Astrophysics Data System (ADS)

Hein, J. D.; Malone, C. P.; Kanik, I.; Johnson, P. V.

2013-12-01

Electron-impact excitation processes involving atomic and molecular oxygen are important in atmospheric interactions. The production of long-lived metastable O(1S) and O(1D) through electron impact of atomic O and molecular O2 play a significant role in the dynamics of oxygen-containing atmospheres (Earth, Europa, Io). Emissions from metastable O (1S → 1D) produce the well-recognized green light from terrestrial aurora. Electron-impact excitation to 1S and 1D are sensitive channels for determining energy partitioning and dynamics from space weather. Electron-impact excitation cross sections determined through fundamental experimental studies are necessary for modeling of natural phenomena and observation data. The detection of metastable states in laboratory experiments requires a novel approach, since typical detection techniques (e.g., fluorescence by radiative de-excitation) cannot be performed due to the long-lived nature of the excited species. In this work, metastable O is incident on a cryogenically cooled rare gas matrix, where excimer production and subsequent rapid radiative de-excitation provides measurable signal that is directly related to the originating electron-impact excitation process.

Unravelling the structural-electronic impact of arylamine electron-donating antennas on the performances of efficient ruthenium sensitizers for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Chen, Wang-Chao; Kong, Fan-Tai; Ghadari, Rahim; Li, Zhao-Qian; Guo, Fu-Ling; Liu, Xue-Peng; Huang, Yang; Yu, Ting; Hayat, Tasawar; Dai, Song-Yuan

2017-04-01

We report a systematic research to understand the structural-electronic impact of the arylamine electron-donating antennas on the performances of the ruthenium complexes for dye-sensitized solar cells. Three ruthenium complexes functionalized with different arylamine electron-donating antennas (N,N-diethyl-aniline in RC-31, julolidine in RC-32 and N,N-dibenzyl-aniline in RC-36) are designed and synthesized. The photoelectric properties of RC dyes exhibit apparent discrepancy, which are ascribed to different structural nature and electronic delocalization ability of these arylamine electron-donating system. In conjunction with TiO2 microspheres photoanode and a typical coadsorbent DPA, the devices sensitized by RC-36 achieve the best conversion efficiency of 10.23%. The UV-Vis absorption, electrochemical measurement, incident photon-to-current conversion efficiency and transient absorption spectra confirm that the excellent performance of RC-36 is induced by synergistically structural-electronic impacts from enhanced absorption capacity and well-tuned electronic characteristics. These observations provide valuable insights into the molecular engineering methodology based on fine tuning structural-electronic impact of electron-donating antenna in efficient ruthenium sensitizers.

Electron impact vibrational excitation of carbon monoxide in the upper atmospheres of Mars and Venus

NASA Astrophysics Data System (ADS)

Campbell, L.; Allan, M.; Brunger, M. J.

2011-09-01

Infrared emission from CO in the upper atmospheres of Mars, Venus and several other planets is a subject of current theoretical and experimental interest. Electron impact excitation makes a contribution that has not been included in previous studies. Given this, and recent new measurements of absolute cross sections for low-energy electron impact excitation of the vibrational levels of the ground state of CO, results from calculations are presented showing the contribution of electron impact relative to emissions by other mechanisms. It is demonstrated that emissions due to the impact of thermal, photo- and auroral electrons are generally small compared to sunlight-driven (fluorescence and photolysis) emissions, but with some exceptions. It is also shown that thermal-electron emissions may dominate over other processes at nighttime at Mars and that auroral emissions certainly do so. While measurements and other calculations do not appear to be available for Venus, the volume emission rates presented should be valuable in planning such measurements.

Effects of electron beam irradiation on chemical composition, antinutritional factors, ruminal degradation and in vitro protein digestibility of canola meal

NASA Astrophysics Data System (ADS)

Taghinejad-Roudbaneh, M.; Ebrahimi, S. R.; Azizi, S.; Shawrang, P.

2010-12-01

The aim of the present study was to determine the impact of electron beam (EB) irradiation at doses of 15, 30 and 45 kGy on the nutritional value of canola meal. The phytic acid and total glucosinolate content of EB-irradiated canola meal decreased as irradiation doses increased ( P<0.01). From in situ results, irradiation of canola meal at doses of 45 kGy decreased ( P<0.05) the effective degradibility of crude protein (CP) by 14%, compared with an untreated sample. In vitro CP digestibility of EB-irradiated canola meal at doses of 15 and 30 kGy was improved ( P<0.05). Electrophoresis results showed that napin and cruciferin sub-units of 30 and 45 kGy EB-irradiated canola meal were more resistant to degradation, compared with an untreated sample. Electron beam irradiation was effective in protecting CP from ruminal degradation and reducing antinutritional factors of irradiated canola meal.

Electronic structure and partial charge distribution of Doxorubicin in different molecular environments.

PubMed

Poudel, Lokendra; Wen, Amy M; French, Roger H; Parsegian, V Adrian; Podgornik, Rudolf; Steinmetz, Nicole F; Ching, Wai-Yim

2015-05-18

The electronic structure and partial charge of doxorubicin (DOX) in three different molecular environments-isolated, solvated, and intercalated in a DNA complex-are studied by first-principles density functional methods. It is shown that the addition of solvating water molecules to DOX, together with the proximity to and interaction with DNA, has a significant impact on the electronic structure as well as on the partial charge distribution. Significant improvement in estimating the DOX-DNA interaction energy is achieved. The results are further elucidated by resolving the total density of states and surface charge density into different functional groups. It is concluded that the presence of the solvent and the details of the interaction geometry matter greatly in determining the stability of DOX complexation. Ab initio calculations on realistic models are an important step toward a more accurate description of the long-range interactions in biomolecular systems. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electron emission from transfer ionization reaction in 30 keV amu‑1 He 2+ on Ar collision

NASA Astrophysics Data System (ADS)

Amaya-Tapia, A.; Antillón, A.; Estrada, C. D.

2018-06-01

A model is presented that describes the transfer ionization process in H{e}2++Ar collision at a projectile energy of 30 keV amu‑1. It is based on a semiclassical independent-particle close-coupling method that yields a reasonable agreement between calculated and experimental values of the total single-ionization and single-capture cross sections. It is found that the transfer ionization reaction is predominantly carried out through simultaneous capture and ionization, rather than by sequential processes. The transfer-ionization differential cross section in energy that is obtained satisfactorily reproduces the global behavior of the experimental data. Additionally, the probabilities of capture and ionization as function of the impact parameter for H{e}2++A{r}+ and H{e}++A{r}+ collisions are calculated, as far as we know, for the first time. The results suggest that the model captures essential elements that describe the two-electron transfer ionization process and could be applied to systems and processes of two electrons.

Atomic structures and electronic properties of 2H-NbSe2: The impact of Ti doping

NASA Astrophysics Data System (ADS)

Li, Hongping; Chen, Lin; Zhang, Kun; Liang, Jiaqing; Tang, Hua; Li, Changsheng; Liu, Xiaojuan; Meng, Jian; Wang, Zhongchang

2014-09-01

Layered transition metal dichalcogenides have aroused renewed interest as electronic materials, yet their electronic performances could be modified by chemical doping. Here, we perform a systematic first-principles calculation to investigate the effect of Ti doping on atomic structure and electronic properties of the 2H-NbSe2. We consider a total of three possible Ti-doping models and find that both the substitution and intercalated models are chemically preferred with the intercalation model being more favorable than the substitution one. Structural analyses reveal a slight lattice distortion triggered by Ti doping, but the original structure of 2H-NbSe2 is maintained. We also observe an expansion of c axis in the substituted model, which is attributed to the reduced van der Waals interaction arising from the increased Se-Se bond length. Our calculations also predict that the electron transport properties can be enhanced by the Ti doping, especially for the Ti-intercalated 2H-NbSe2, which should be beneficial for the realization of superconductivity. Furthermore, the covalence element is found in the Ti-Se bonds, which is ascribed to the hybridization of Ti 3d and Se 4p orbitals. The findings indicate that doping of transition metals can be regarded as a useful way to tailor electronic states so as to improve electron transport properties of 2H-NbSe2.

Impact evaluation of conducted UWB transients on loads in power-line networks

NASA Astrophysics Data System (ADS)

Li, Bing; Månsson, Daniel

2017-09-01

Nowadays, faced with the ever-increasing dependence on diverse electronic devices and systems, the proliferation of potential electromagnetic interference (EMI) becomes a critical threat for reliable operation. A typical issue is the electronics working reliably in power-line networks when exposed to electromagnetic environment. In this paper, we consider a conducted ultra-wideband (UWB) disturbance, as an example of intentional electromagnetic interference (IEMI) source, and perform the impact evaluation at the loads in a network. With the aid of fast Fourier transform (FFT), the UWB transient is characterized in the frequency domain. Based on a modified Baum-Liu-Tesche (BLT) method, the EMI received at the loads, with complex impedance, is computed. Through inverse FFT (IFFT), we obtain time-domain responses of the loads. To evaluate the impact on loads, we employ five common, but important quantifiers, i.e., time-domain peak, total signal energy, peak signal power, peak time rate of change and peak time integral of the pulse. Moreover, to perform a comprehensive analysis, we also investigate the effects of the attributes (capacitive, resistive, or inductive) of other loads connected to the network, the rise time and pulse width of the UWB transient, and the lengths of power lines. It is seen that, for the loads distributed in a network, the impact evaluation of IEMI should be based on the characteristics of the IEMI source, and the network features, such as load impedances, layout, and characteristics of cables.

Evidence for Neutrals-Foreshock Electrons Impact at Mars

NASA Astrophysics Data System (ADS)

Mazelle, C. X.; Meziane, K.; Mitchell, D. L.; Garnier, P.; Espley, J. R.; Hamza, A. M.; Halekas, J.; Jakosky, B. M.

2018-05-01

Backstreaming electrons emanating from the bow shock of Mars reported from the Mars Atmosphere and Volatile EvolutioN/Solar Wind Electron Analyzer observations show a flux fall off with the distance from the shock. This feature is not observed at the terrestrial foreshock. The flux decay is observed only for electron energy E ≥ 29 eV. A reported recent study indicates that Mars foreshock electrons are produced at the shock in a mirror reflection of a portion of the solar wind electrons. In this context, and given that the electrons are sufficiently energetic to not be affected by the interplanetary magnetic field fluctuations, the observed flux decrease appears problematic. We investigate the possibility that the flux fall off with distance results from the impact of backstreaming electrons with Mars exospheric neutral hydrogen. We demonstrate that the flux fall off is consistent with the electron-atomic hydrogen impact cross section for a large range of energy. A better agreement is obtained for energy where the impact cross section is the highest. One important consequence is that foreshock electrons can play an important role in the production of pickup ions at Mars far exosphere.

Charging of Individual Micron-Size Interstellar/Planetary Dust Grains by Secondary Electron Emissions

NASA Technical Reports Server (NTRS)

Tankosic, D.; Abbas, M. M.

2012-01-01

Dust grains in various astrophysical environments are generally charged electrostatically by photoelectric emissions with UV/X-ray radiation, as well as by electron/ion impact. Knowledge of physical and optical properties of individual dust grains is required for understanding of the physical and dynamical processes in space environments and the role of dust in formation of stellar and planetary systems. In this paper, we discuss experimental results on dust charging by electron impact, where low energy electrons are scattered or stick to the dust grains, thereby charging the dust grains negatively, and at sufficiently high energies the incident electrons penetrate the grain leading to excitation and emission of electrons referred to as secondary electron emission (SEE). Currently, very limited experimental data are available for charging of individual micron-size dust grains, particularly by low energy electron impact. Available theoretical models based on the Sternglass equation (Sternglass, 1954) are applicable for neutral, planar, and bulk surfaces only. However, charging properties of individual micron-size dust grains are expected to be different from the values measured on bulk materials. Our recent experimental results on individual, positively charged, micron-size lunar dust grains levitated in an electrodynamic balance facility (at NASA-MSFC) indicate that the SEE by electron impact is a complex process. The electron impact may lead to charging or discharging of dust grains depending upon the grain size, surface potential, electron energy, electron flux, grain composition, and configuration (e.g. Abbas et al, 2010). Here we discuss the complex nature of SEE charging properties of individual micron-size lunar dust grains and silica microspheres.

Control of secondary electrons from ion beam impact using a positive potential electrode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crowley, T. P., E-mail: tpcrowley@xanthotechnologies.com; Demers, D. R.; Fimognari, P. J.

2016-11-15

Secondary electrons emitted when an ion beam impacts a detector can amplify the ion beam signal, but also introduce errors if electrons from one detector propagate to another. A potassium ion beam and a detector comprised of ten impact wires, four split-plates, and a pair of biased electrodes were used to demonstrate that a low-voltage, positive electrode can be used to maintain the beneficial amplification effect while greatly reducing the error introduced from the electrons traveling between detector elements.

School Superintendents' Use of Electronic Communication Technology and Its Impact on Their Efficacy as a School District Leader

ERIC Educational Resources Information Center

Brock, Cecilia

2017-01-01

As apex leaders, school superintendents are impacted by the continuous demand to be effective while utilizing electronic communication technology. The purpose of this study is to investigate how the use of electronic communication technology impacts a school superintendent's efficacy. Public education, in the twenty-first century, finds itself in…

The Electronic-Vibrational Behaviour of O2 in the Upper Atmosphere under Night-time Auroral Conditions

NASA Astrophysics Data System (ADS)

Jones, D. B.; Cartwright, D. C.; Campbell, L.; Teubner, P. J. O.; Brunger, M. J.; Bottema, M. J.

2004-09-01

We report on the extension of our Statistical Equlibrium Code (SEC) to determine the electronic-vibrational behaviour of O2 in the thermosphere, under night-time auroral conditions. This work was necessitated by the inadequacies in previous studies where the electron-impact cross section data bases employed have been superceeded, and/or direct excitation of states via electron impact has been neglected. Here we use the latest electron-impact cross section data bases to present the first electron-impact excitation rates for the 8 lowest lying electronic states of O_2. We then use these rates in conjunction with the most accurately available Franck-Condon factors, transition probabilities and quenching rates to determine the excited state populations. Note that predissociation, which is important for O_2, is also included in our model. We present radiative rates for various transitions and compare these results with those from other models and experimental rocket measurements.

Electron-Impact Ionization and Dissociative Ionization of Biomolecules

NASA Technical Reports Server (NTRS)

Huo, Winifred M.; Chaban, Galina M.; Dateo, Christopher E.

2006-01-01

It is well recognized that secondary electrons play an important role in radiation damage to humans. Particularly important is the damage of DNA by electrons, potentially leading to mutagenesis. Molecular-level study of electron interaction with DNA provides information on the damage pathways and dominant mechanisms. Our study of electron-impact ionization of DNA fragments uses the improved binary-encounter dipole model and covers DNA bases, sugar phosphate backbone, and nucleotides. An additivity principle is observed. For example, the sum of the ionization cross sections of the separate deoxyribose and phosphate fragments is in close agreement with the C3(sup prime)- and C5 (sup prime)-deoxyribose-phospate cross sections, differing by less than 5%. Investigation of tandem double lesion initiated by electron-impact dissociative ionization of guanine, followed by proton reaction with the cytosine in the Watson-Crick pair, is currently being studied to see if tandem double lesion can be initiated by electron impact. Up to now only OH-induced tandem double lesion has been studied.

Dissociative attachment of electrons to N2O

NASA Technical Reports Server (NTRS)

Krishnakumar, E.; Srivastava, S. K.

1990-01-01

Cross sections for the production of O(-) from N2O by the process of dissociative electron attachment have been measured for electron-impact energies ranging from 0 to 50 eV. Three new O(-) peaks are observed. The present data above 5-eV electron-impact energy differ considerably from the previous measurements.

Impact of Information Technology-Based Interventions for Type 2 Diabetes Mellitus on Glycemic Control: A Systematic Review and Meta-Analysis.

PubMed

Alharbi, Nouf Sahal; Alsubki, Nada; Jones, Simon; Khunti, Kamlesh; Munro, Neil; de Lusignan, Simon

2016-11-25

Information technology-based interventions are increasingly being used to manage health care. However, there is conflicting evidence regarding whether these interventions improve outcomes in people with type 2 diabetes. The objective of this study was to conduct a systematic review and meta-analysis of clinical trials, assessing the impact of information technology on changes in the levels of hemoglobin A 1c (HbA 1c ) and mapping the interventions with chronic care model (CCM) elements. Electronic databases PubMed and EMBASE were searched to identify relevant studies that were published up until July 2016, a method that was supplemented by identifying articles from the references of the articles already selected using the electronic search tools. The study search and selection were performed by independent reviewers. Of the 1082 articles retrieved, 32 trials (focusing on a total of 40,454 patients) were included. A random-effects model was applied to estimate the pooled results. Information technology-based interventions were associated with a statistically significant reduction in HbA 1c levels (mean difference -0.33%, 95% CI -0.40 to -0.26, P<.001). Studies focusing on electronic self-management systems demonstrated the largest reduction in HbA 1c (0.50%), followed by those with electronic medical records (0.17%), an electronic decision support system (0.15%), and a diabetes registry (0.05%). In addition, the more CCM-incorporated the information technology-based interventions were, the more improvements there were in HbA 1c levels. Information technology strategies combined with the other elements of chronic care models are associated with improved glycemic control in people with diabetes. No clinically relevant impact was observed on low-density lipoprotein levels and blood pressure, but there was evidence that the cost of care was lower. ©Nouf Sahal Alharbi, Nada Alsubki, Simon Jones, Kamlesh Khunti, Neil Munro, Simon de Lusignan. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 25.11.2016.

Triply differential measurements of single ionization of argon by 1-keV positron and electron impact

NASA Astrophysics Data System (ADS)

Gavin, J.; de Lucio, O. G.; DuBois, R. D.

2017-06-01

By establishing coincidences between target ions and scattered projectiles, and coincidences between target ions, scattered projectiles, and ejected electrons, triply differential cross-section (TDCS) information was generated in terms of projectile energy loss and scattering angles for interactions between 1-keV positrons and electrons and Ar atoms. The conversion of the raw experimental information to the TDCS is discussed. The single-ionization TDCS exhibits two distinguishable regions (lobes) where binary and recoil interactions can be described by two peaks. A comparison of the positron and electron impact data shows that the relative intensity of both binary and recoil interactions decreases exponentially as a function of the momentum transfer and is larger when ionization is induced by positron impact, when compared with electron impact.

Study and Modeling of the Impact of TID on the ATREE Response in LM124 Operational Amplifier

NASA Astrophysics Data System (ADS)

Roig, Fabien; Dusseau, L.; Ribeiro, P.; Auriel, G.; Roche, N. J.-H.; Privat, A.; Vaillé, J.-R.; Boch, J.; Saigné, F.; Marec, R.; Calvel, P.; Bezerra, F.; Ecoffet, R.; Azais, B.

2014-08-01

Shapes of ATREEs (Analog Transient Radiation Effects on Electronics) in a bipolar integrated circuit change with exposure to Total Ionizing Dose (TID) radiation. The impact of TID on ATREEs is investigated in the LM124 operational amplifier (opamp) from three different manufacturers. Significant variations are observed on the ATREE responsesfrom different manufacturers. The ATREEs are produced by pulsed X-ray experiments. ASET laser mappings are performed to highlight the sensitive bipolar transistors, explaining the ATREE phenomena variations from one manufacturer to another one. ATREE modeling results are presented using a previously developed simulation tool. A good agreement is observed between experimental ATREE responses and model outputs whatever the TID level, the prompt dose level, the amplifier configuration and the device manufacturer.

Impact of Internally Developed Electronic Prescription on Prescribing Errors at Discharge from the Emergency Department

PubMed Central

Hitti, Eveline; Tamim, Hani; Bakhti, Rinad; Zebian, Dina; Mufarrij, Afif

2017-01-01

Introduction Medication errors are common, with studies reporting at least one error per patient encounter. At hospital discharge, medication errors vary from 15%–38%. However, studies assessing the effect of an internally developed electronic (E)-prescription system at discharge from an emergency department (ED) are comparatively minimal. Additionally, commercially available electronic solutions are cost-prohibitive in many resource-limited settings. We assessed the impact of introducing an internally developed, low-cost E-prescription system, with a list of commonly prescribed medications, on prescription error rates at discharge from the ED, compared to handwritten prescriptions. Methods We conducted a pre- and post-intervention study comparing error rates in a randomly selected sample of discharge prescriptions (handwritten versus electronic) five months pre and four months post the introduction of the E-prescription. The internally developed, E-prescription system included a list of 166 commonly prescribed medications with the generic name, strength, dose, frequency and duration. We included a total of 2,883 prescriptions in this study: 1,475 in the pre-intervention phase were handwritten (HW) and 1,408 in the post-intervention phase were electronic. We calculated rates of 14 different errors and compared them between the pre- and post-intervention period. Results Overall, E-prescriptions included fewer prescription errors as compared to HW-prescriptions. Specifically, E-prescriptions reduced missing dose (11.3% to 4.3%, p <0.0001), missing frequency (3.5% to 2.2%, p=0.04), missing strength errors (32.4% to 10.2%, p <0.0001) and legibility (0.7% to 0.2%, p=0.005). E-prescriptions, however, were associated with a significant increase in duplication errors, specifically with home medication (1.7% to 3%, p=0.02). Conclusion A basic, internally developed E-prescription system, featuring commonly used medications, effectively reduced medication errors in a low-resource setting where the costs of sophisticated commercial electronic solutions are prohibitive. PMID:28874948

Impact of Internally Developed Electronic Prescription on Prescribing Errors at Discharge from the Emergency Department.

PubMed

Hitti, Eveline; Tamim, Hani; Bakhti, Rinad; Zebian, Dina; Mufarrij, Afif

2017-08-01

Medication errors are common, with studies reporting at least one error per patient encounter. At hospital discharge, medication errors vary from 15%-38%. However, studies assessing the effect of an internally developed electronic (E)-prescription system at discharge from an emergency department (ED) are comparatively minimal. Additionally, commercially available electronic solutions are cost-prohibitive in many resource-limited settings. We assessed the impact of introducing an internally developed, low-cost E-prescription system, with a list of commonly prescribed medications, on prescription error rates at discharge from the ED, compared to handwritten prescriptions. We conducted a pre- and post-intervention study comparing error rates in a randomly selected sample of discharge prescriptions (handwritten versus electronic) five months pre and four months post the introduction of the E-prescription. The internally developed, E-prescription system included a list of 166 commonly prescribed medications with the generic name, strength, dose, frequency and duration. We included a total of 2,883 prescriptions in this study: 1,475 in the pre-intervention phase were handwritten (HW) and 1,408 in the post-intervention phase were electronic. We calculated rates of 14 different errors and compared them between the pre- and post-intervention period. Overall, E-prescriptions included fewer prescription errors as compared to HW-prescriptions. Specifically, E-prescriptions reduced missing dose (11.3% to 4.3%, p <0.0001), missing frequency (3.5% to 2.2%, p=0.04), missing strength errors (32.4% to 10.2%, p <0.0001) and legibility (0.7% to 0.2%, p=0.005). E-prescriptions, however, were associated with a significant increase in duplication errors, specifically with home medication (1.7% to 3%, p=0.02). A basic, internally developed E-prescription system, featuring commonly used medications, effectively reduced medication errors in a low-resource setting where the costs of sophisticated commercial electronic solutions are prohibitive.

Electron-Impact Total Ionization Cross Sections of Fluorine Compounds

NASA Astrophysics Data System (ADS)

Kim, Y.-K.; Ali, M. A.; Rudd, M. E.

1997-10-01

A theoretical method called the Binary-Encounter-Bethe (BEB) model(M. A. Ali, Y.-K. Kim, H. Hwang, N. M. Weinberger, and M. E. Rudd, J. Chem. Phys. 106), 9602 (1997), and references therein. that combines the Mott cross section at low incident energies T and the Bethe cross section at high T was applied to fluorine compounds of interest to plasma processing of semiconductors (CF_4, CHF_3, C_2F_6, C_4F_8, etc.). The theory provides total ioniztion cross sections in an analytic form from the threshold to a few keV in T, making it convenient to use the theory for modeling. The theory is particularly effective for closed-shell molecules. The theoretical cross sections are compared to available experimental data.

Influence of renormalization shielding on the electron-impact ionization process in dense partially ionized plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Mi-Young; Yoon, Jung-Sik; Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr

2015-04-15

The renormalization shielding effects on the electron-impact ionization of hydrogen atom are investigated in dense partially ionized plasmas. The effective projectile-target interaction Hamiltonian and the semiclassical trajectory method are employed to obtain the transition amplitude as well as the ionization probability as functions of the impact parameter, the collision energy, and the renormalization parameter. It is found that the renormalization shielding effect suppresses the transition amplitude for the electron-impact ionization process in dense partially ionized plasmas. It is also found that the renormalization effect suppresses the differential ionization cross section in the peak impact parameter region. In addition, it ismore » found that the influence of renormalization shielding on the ionization cross section decreases with an increase of the relative collision energy. The variations of the renormalization shielding effects on the electron-impact ionization cross section are also discussed.« less

Assessing the impact of a web-based comprehensive somatic and mental health screening tool in pediatric primary care.

PubMed

Fothergill, Kate E; Gadomski, Anne; Solomon, Barry S; Olson, Ardis L; Gaffney, Cecelia A; Dosreis, Susan; Wissow, Lawrence S

2013-01-01

To evaluate how parents and physicians perceive the utility of a comprehensive, electronic previsit screener, and to assess its impact on the visit. A mixed methods design was used. English-speaking parents were recruited from 3 primary care systems (urban MD and rural NY and VT) when they presented for a well-child visit with a child 4 to 10 years of age. Parents completed an electronic previsit screen, which included somatic concerns, health risks, and 4 mental health tools (SCARED5, PHQ-2, SDQ Impact, and PSC-17). Parents completed an exit survey, and a subset were interviewed. All primary care providers (PCPs) were interviewed. A total of 120 parents and 16 PCPs participated. The exit surveys showed that nearly 90% of parents agreed or strongly agreed that the screener was easy to use and maintained confidentiality. During interviews, parents noted that the screener helped with recall, validated concerns, reframed issues they thought might not be appropriate for primary care, and raised new questions. PCPs thought that the screener enabled them to normalize sensitive issues, and it permitted them to simultaneously focus and be comprehensive during the visit. Parents and PCPs agreed that the screener helped guide discussion, promoted in-depth exchange, and increased efficiency. Findings were consistent across quantitative and qualitative methods and between parents and PCPs. A comprehensive electronic previsit screening tool is an acceptable and practical strategy to facilitate well-child visits. It may help with problem identification as well as with setting agendas, engaging the family, and balancing attention between somatic and psychosocial concerns. Copyright © 2013 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

Single impacts of keV fullerene ions on free standing graphene: Emission of ions and electrons from confined volume

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verkhoturov, Stanislav V.; Geng, Sheng; Schweikert, Emile A., E-mail: schweikert@chem.tamu.edu

We present the first data from individual C{sub 60} impacting one to four layer graphene at 25 and 50 keV. Negative secondary ions and electrons emitted in transmission were recorded separately from each impact. The yields for C{sub n}{sup −} clusters are above 10% for n ≤ 4, they oscillate with electron affinities and decrease exponentially with n. The result can be explained with the aid of MD simulation as a post-collision process where sufficient vibrational energy is accumulated around the rim of the impact hole for sputtering of carbon clusters. The ionization probability can be estimated by comparing experimentalmore » yields of C{sub n}{sup −} with those of C{sub n}{sup 0} from MD simulation, where it increases exponentially with n. The ionization probability can be approximated with ejecta from a thermally excited (3700 K) rim damped by cluster fragmentation and electron detachment. The experimental electron probability distributions are Poisson-like. On average, three electrons of thermal energies are emitted per impact. The thermal excitation model invoked for C{sub n}{sup −} emission can also explain the emission of electrons. The interaction of C{sub 60} with graphene is fundamentally different from impacts on 3D targets. A key characteristic is the high degree of ionization of the ejecta.« less

Rate coefficients for dissociative attachment and resonant electron-impact dissociation involving vibrationally excited O{sub 2} molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laporta, V.; Celiberto, R.; Tennyson, J.

Rate coefficients for dissociative electron attachment and electron-impact dissociation processes, involving vibrationally excited molecular oxygen, are presented. Analytical fits of the calculated numerical data, useful in the applications, are also provided.

The impact of interoperability of electronic health records on ambulatory physician practices: a discrete-event simulation study.

PubMed

Zhou, Yuan; Ancker, Jessica S; Upadhye, Mandar; McGeorge, Nicolette M; Guarrera, Theresa K; Hegde, Sudeep; Crane, Peter W; Fairbanks, Rollin J; Bisantz, Ann M; Kaushal, Rainu; Lin, Li

2013-01-01

The effect of health information technology (HIT) on efficiency and workload among clinical and nonclinical staff has been debated, with conflicting evidence about whether electronic health records (EHRs) increase or decrease effort. None of this paper to date, however, examines the effect of interoperability quantitatively using discrete event simulation techniques. To estimate the impact of EHR systems with various levels of interoperability on day-to-day tasks and operations of ambulatory physician offices. Interviews and observations were used to collect workflow data from 12 adult primary and specialty practices. A discrete event simulation model was constructed to represent patient flows and clinical and administrative tasks of physicians and staff members. High levels of EHR interoperability were associated with reduced time spent by providers on four tasks: preparing lab reports, requesting lab orders, prescribing medications, and writing referrals. The implementation of an EHR was associated with less time spent by administrators but more time spent by physicians, compared with time spent at paper-based practices. In addition, the presence of EHRs and of interoperability did not significantly affect the time usage of registered nurses or the total visit time and waiting time of patients. This paper suggests that the impact of using HIT on clinical and nonclinical staff work efficiency varies, however, overall it appears to improve time efficiency more for administrators than for physicians and nurses.

Impact of electronic health records on the patient experience in a hospital setting.

PubMed

Migdal, Christopher W; Namavar, Aram A; Mosley, Virgie N; Afsar-manesh, Nasim

2014-10-01

The impact of electronic health records (EHRs) and their effects on optimizing the patient experience has been debated nationally. Currently, there is a paucity of data in this area, and existing research offers conflicting results. Since 2006, the Assessing Residents' CI-CARE (ARC) program has evaluated the physician-patient interaction of resident physicians at University of California, Los Angeles (UCLA) Health utilizing a 20-item questionnaire administered through facilitator-patient interviews. To evaluate the impact of EHR implementation on the patient experience. Retrospective cohort study. Two academic medical campuses: Ronald Reagan UCLA Medical Center and UCLA Medical Center, Santa Monica. A total of 3417 surveys, spanning December 1, 2012 to May 30, 2013, were assessed. This included patient representation from 9 departments within UCLA Health. Surveys were analyzed to assess physician-patient communication. Statistical comparisons were made using χ analysis. All 16 questions assessing physician-patient communication received better responses in the 3 months following EHR implementation, compared to the 3 months prior to implementation. Of these, 9 questions illustrated statistically significant improvement, whereas the improvement in the remaining 7 questions was not statistically significant. These results suggest that EHRs may improve physician-patient communication. The ARC infrastructure allowed for observation of this trend; however, future research should aim to further validate and understand the etiologies of this improvement. © 2014 Society of Hospital Medicine.

Electron impact action spectroscopy of mass/charge selected macromolecular ions: Inner-shell excitation of ubiquitin protein

NASA Astrophysics Data System (ADS)

Ranković, Miloš Lj.; Giuliani, Alexandre; Milosavljević, Aleksandar R.

2016-02-01

We have performed inner-shell electron impact action spectroscopy of mass and charge selected macromolecular ions. For this purpose, we have coupled a focusing electron gun with a linear quadrupole ion trap mass spectrometer. This experiment represents a proof of principle that an energy-tunable electron beam can be used in combination with radio frequency traps as an activation method in tandem mass spectrometry (MS2) and allows performing action spectroscopy. Electron impact MS2 spectra of multiply protonated ubiquitin protein ion have been recorded at incident electron energies around the carbon 1 s excitation. Both MS2 and single ionization energy dependence spectra are compared with literature data obtained using the soft X-ray activation conditions.

Experimental Investigation of Charging Properties of Interstellar Type Silica Dust Grains by Secondary Electron Emissions

NASA Technical Reports Server (NTRS)

Tankosic, D.; Abbas, M. M.

2013-01-01

The dust charging by electron impact is an important dust charging processes in astrophysical and planetary environments. Incident low energy electrons are reflected or stick to the grains charging the dust grains negatively. At sufficiently high energies electrons penetrate the grains, leading to excitation and emission of electrons referred to as secondary electron emission (SEE). Available classical theoretical models for calculations of SEE yields are generally applicable for neutral, planar, or bulk surfaces. These models, however, are not valid for calculations of the electron impact charging properties of electrostatically charged micron/submicron-size dust grains in astrophysical environments. Rigorous quantum mechanical models are not yet available, and the SEE yields have to be determined experimentally for development of more accurate models for charging of individual dust grains. At the present time, very limited experimental data are available for charging of individual micron-size dust grains, particularly for low energy electron impact. The experimental results on individual, positively charged, micron-size lunar dust grains levitated carried out by us in a unique facility at NASA-MSFC, based on an electrodynamic balance, indicate that the SEE by electron impact is a complex process. The electron impact may lead to charging or discharging of dust grains depending upon the grain size, surface potential, electron energy, electron flux, grain composition, and configuration (Abbas et al, 2010, 2012). In this paper, we discuss SEE charging properties of individual micron-size silica microspheres that are believed to be analogs of a class of interstellar dust grains. The measurements indicate charging of the 0.2m silica particles when exposed to 25 eV electron beams and discharging when exposed to higher energy electron beams. Relatively large size silica particles (5.2-6.82m) generally discharge to lower equilibrium potentials at both electron energies. These measurements conducted on silica microspheres are qualitatively similar in nature to our previous SEE measurements on lunar Apollo missions dust samples.

The impact of methionine source on poultry fecal matter odor volatiles.

PubMed

Chavez, C; Coufal, C D; Lacey, R E; Carey, J B

2004-03-01

To determine the impact of Met source on volatile compounds of broiler excreta, 2 trials were conducted using straight-run broiler chicks that were randomly distributed in battery cages with 3 replicate pens of 16 birds each. The treatment groups were 1) dry Met hydroxy analogue (52% Met activity), 2) sodium methioninate aqueous solution (45.9% Met activity), 3) liquid Met hydroxy analogue (88% Met activity), 4) DL-Met, (98% Met activity), and 5) no supplemental Met. All starter diets were formulated to contain 3,135 kcal of ME/kg, 23% crude protein, and 0.8% total Met activity and otherwise met NRC nutrient requirements. Diets were fed ad libitum from d 1 to termination of the study (5 to 6 wk). Feed consumption and feed conversion were measured daily, and all birds were weighed weekly. There were no significant differences in BW, feed consumption, or feed conversion among the treatments in either trial. All excreta were collected in litter pans daily lined with aluminum foil. Litter pans for each pen were individually transferred to a separate room for weekly odor volatile analysis. An electronic nose was used to capture 3 to 4 air samples from various locations for each pan of broiler excreta resulting in a total of 10 air samples from each treatment group. All data taken from the electronic nose were evaluated using analysis of variance. Results indicated that there were significant differences in volatiles in the broiler excreta for all treatment groups. These data indicate that different Met sources may result in the production of different odor-related compounds in broiler excreta.

Failure mode and effect analysis oriented to risk-reduction interventions in intraoperative electron radiation therapy: the specific impact of patient transportation, automation, and treatment planning availability.

PubMed

López-Tarjuelo, Juan; Bouché-Babiloni, Ana; Santos-Serra, Agustín; Morillo-Macías, Virginia; Calvo, Felipe A; Kubyshin, Yuri; Ferrer-Albiach, Carlos

2014-11-01

Industrial companies use failure mode and effect analysis (FMEA) to improve quality. Our objective was to describe an FMEA and subsequent interventions for an automated intraoperative electron radiotherapy (IOERT) procedure with computed tomography simulation, pre-planning, and a fixed conventional linear accelerator. A process map, an FMEA, and a fault tree analysis are reported. The equipment considered was the radiance treatment planning system (TPS), the Elekta Precise linac, and TN-502RDM-H metal-oxide-semiconductor-field-effect transistor in vivo dosimeters. Computerized order-entry and treatment-automation were also analyzed. Fifty-seven potential modes and effects were identified and classified into 'treatment cancellation' and 'delivering an unintended dose'. They were graded from 'inconvenience' or 'suboptimal treatment' to 'total cancellation' or 'potentially wrong' or 'very wrong administered dose', although these latter effects were never experienced. Risk priority numbers (RPNs) ranged from 3 to 324 and totaled 4804. After interventions such as double checking, interlocking, automation, and structural changes the final total RPN was reduced to 1320. FMEA is crucial for prioritizing risk-reduction interventions. In a semi-surgical procedure like IOERT double checking has the potential to reduce risk and improve quality. Interlocks and automation should also be implemented to increase the safety of the procedure. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Complete solution of electronic excitation and ionization in electron-hydrogen molecule scattering

DOE PAGES

Zammit, Mark C.; Savage, Jeremy S.; Fursa, Dmitry V.; ...

2016-06-08

The convergent close-coupling method has been used to solve the electron-hydrogen molecule scattering problem in the fixed-nuclei approximation. Excellent agreement with experiment is found for the grand total, elastic, electronic-excitation, and total ionization cross sections from the very low to the very high energies. This shows that for the electronic degrees of freedom the method provides a complete treatment of electron scattering on molecules as it does for atoms.

Electron impact cross-sections and cooling rates for methane. [in thermal balance of electrons in atmospheres and ionospheres of planets and satellites in outer solar system

NASA Technical Reports Server (NTRS)

Gan, L.; Cravens, T. E.

1992-01-01

Energy transfer between electrons and methane gas by collisional processes plays an important role in the thermal balance of electrons in the atmospheres and ionospheres of planets and satellites in the outer solar system. The literature is reviewed for electron impact cross-sections for methane in this paper. Energy transfer rates are calculated for elastic and inelastic processes using a Maxwellian electron distribution. Vibrational, rotational, and electronic excitation and ionization are included. Results are presented for a wide range of electron temperatures and neutral temperatures.

Impact of sodium lauryl sulfate in oral liquids on e-tongue measurements.

PubMed

Immohr, Laura Isabell; Turner, Roy; Pein-Hackelbusch, Miriam

2016-12-30

During development of oral liquid medicines taste assessment is often required to evaluate taste and taste masking. Electronic tongue analysis can provide taste assessment of medicinal products but should only be conducted with medicines that interact with the instrument without damaging the sensor membranes or interfering with their electrical output so that robust data is generated. To explore the impact of a substance deemed unsuitable for electronic tongue analysis the influence of the anionic surfactant sodium lauryl sulfate (SLS), on the performance of the electronic tongue was conducted using electronic tongues equipped with self-developed PVC based sensors. The results showed a significant impact of SLS on all applied sensor types and an alteration of the sensor's sensitivity. Nevertheless, concentration dependent sensor responses could still be obtained and the sensor performance was not impacted negatively. Assessment of unsuitable substances should therefore be evaluated prior to performing electronic tongue analysis so that their impact is understood fully. Copyright © 2016 Elsevier B.V. All rights reserved.

Electron impact contribution to infrared NO emissions in auroral conditions

NASA Astrophysics Data System (ADS)

Campbell, L.; Brunger, M. J.

2007-11-01

Infrared emissions from nitric oxide, other than nightglow, are observed in aurora, principally due to a chemiluminescent reaction between excited nitrogen atoms and oxygen molecules that produces vibrationally excited NO. The rates for this chemiluminescent reaction have recently been revised. Based on new measurements of electron impact vibrational excitation of NO, it has been suggested that electron impact may also be significant in producing auroral NO emissions. We show results of a detailed calculation which predicts the infrared spectrum observed in rocket measurements, using the revised chemiluminescent rates and including electron impact excitation. For emissions from the second vibrational level and above, the shape of the spectrum can be reproduced within the statistical errors of the analysis of the measurements, although there is an unexplained discrepancy in the absolute value of the emissions. The inclusion of electron impact improves the agreement of the shape of the predicted spectrum with the measurements by accounting for part of the previously unexplained peak in emissions from the first vibrational level.

Projectile-charge dependence of the differential cross section for the ionization of argon atoms at 1 keV

NASA Astrophysics Data System (ADS)

Purohit, G.; Kato, D.

2017-10-01

The single ionization triple differential cross sections (TDCS) of the Ar (3 p ) atoms are reported for the positron and electron impact at 1 keV. The calculated cross sections have been obtained using distorted wave Born approximation (DWBA) approach for the average ejected electron energies 13 and 26 eV at different momentum transfer conditions. The present attempt is helpful to probe the information on the TDCS trends for the particle-matter and antiparticle-matter interactions and to analyze the recent measurements [Phy. Rev. A 95, 062703 (2017), 10.1103/PhysRevA.95.062703]. The binary electron emission is enhanced while the recoil emission is decreased for the positron impact relative to the electron impact in the DWBA calculation results. Systematic shift of peaks, shifting away from the momentum transfer direction for positron impact and shifting towards each other for electron impact, is observed with increasing momentum transfer.

Effective collision strengths for fine-structure forbidden transitions among the 3s^23p^3 levels of AR IV

NASA Astrophysics Data System (ADS)

Ramsbottom, C. A.; Bell, K. L.; Keenan, F. P.

1997-01-01

The multichannel R-matrix method is used to compute electron impact excitation collision strengths in Ar iv for all fine-structure transitions among the ^4S^o, ^2D^o and ^2P^o levels in the 3s^23p^3 ground configuration. Included in the expansion of the total wavefunction are the lowest 13 LS target eigenstates of Ar iv formed from the 3s^23p^3, 3s3p^4 and 3s^23p^23d configurations. The effective collision strengths, obtained by averaging the electron collision strengths over a Maxwellian distribution of electron velocities, are presented for all 10 fine-structure transitions over a wide range of electron temperatures of astrophysical interest (T_e=2000-100 000K). Comparisons are made with an earlier 7-state close-coupling calculation by Zeippen, Butler & Le Bourlot, and significant differences are found to occur for many of the forbidden transitions considered, in particular those involving the ^4S^o ground state, where discrepancies of up to a factor of 3 are found in the low-temperature region.

Mitigation strategies against radiation-induced background for space astronomy missions

NASA Astrophysics Data System (ADS)

Davis, C. S. W.; Hall, D.; Keelan, J.; O'Farrell, J.; Leese, M.; Holland, A.

2018-01-01

The Advanced Telescope for High ENergy Astrophysics (ATHENA) mission is a major upcoming space-based X-ray observatory due to be launched in 2028 by ESA, with the purpose of mapping the early universe and observing black holes. Background radiation is expected to constitute a large fraction of the total system noise in the Wide Field Imager (WFI) instrument on ATHENA, and designing an effective system to reduce the background radiation impacting the WFI will be crucial for maximising its sensitivity. Significant background sources are expected to include high energy protons, X-ray fluorescence lines, 'knock-on' electrons and Compton electrons. Due to the variety of the different background sources, multiple shielding methods may be required to achieve maximum sensitivity in the WFI. These techniques may also be of great interest for use in future space-based X-ray experiments. Simulations have been developed to model the effect of a graded-Z shield on the X-ray fluorescence background. In addition the effect of a 90nm optical blocking filter on the secondary electron background has been investigated and shown to modify the requirements of any secondary electron shielding that is to be used.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biswas, Shubhadeep; Champion, Christophe; Weck, P. F.

Interaction between polycyclic aromatic hydrocarbon (PAH) molecule and energetic ion is a subject of interest in different areas of modern physics. Here, we present measurements of energy and angular distributions of absolute double differential electron emission cross section for coronene (C 24H 12) and fluorene (C 13H 10) molecules under fast bare oxygen ion impact. For coronene, the angular distributions of the low energy electrons are quite different from that of simpler targets like Ne or CH 4, which is not the case for fluorene. The behaviour of the higher electron energy distributions for both the targets are similar tomore » that for simple targets. In case of coronene, a clear signature of plasmon resonance is observed in the analysis of forward-backward angular asymmetry of low energy electron emission. For fluorene, such signature is not identified probably due to lower oscillator strength of plasmon compared to the coronene. The theoretical calculation based on the first-order Born approximation with correct boundary conditions (CB1), in general, reproduced the experimental observations qualitatively, for both the molecules, except in the low energy region for coronene, which again indicates the role of collective excitation. Single differential and total cross sections are also deduced. An overall comparative study is presented.« less

Nanominerals and potentially hazardous elements from coal cleaning rejects of abandoned mines: Environmental impact and risk assessment.

PubMed

Fdez-Ortiz de Vallejuelo, Silvia; Gredilla, Ainara; da Boit, Kátia; Teixeira, Elba C; Sampaio, Carlos H; Madariaga, Juan Manuel; Silva, Luis F O

2017-02-01

Soils around coal mining are important reservoir of hazardous elements (HEs), nanominerals, and ultrafine compounds. This research reports and discusses the soil concentrations of HEs (As, Cd, Cr, Cu, Ni, Pb, and Zn) in coal residues of abandoned mines. To assess differences regarding environmental impact and risk assessment between coal abandoned mines from the Santa Catarina state, eighteen coal cleaning rejects with different mineralogical and chemical composition, from eight abandoned mines were collected. Nanominerals and ultra-fine minerals from mining-contaminated areas were analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscope (HR-TEM), providing new information on the mineralogy and nano-mineralogy of these coal residues. The total contents of 57 elements (HEs, alkali metals, and rare earth elements) were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The calculation of NWACs (Normalized Average Weighted Concentration), together with the chemometric analysis by Principal component analysis (PCA) confirmed the variability of the samples regarding their city and their mine of origin. Moreover, the results confirmed the existence of hotspots in mines near urban areas. Copyright © 2016 Elsevier Ltd. All rights reserved.

A tutorial on activity-based costing of electronic health records.

PubMed

Federowicz, Marie H; Grossman, Mila N; Hayes, Bryant J; Riggs, Joseph

2010-01-01

As the American Recovery and Restoration Act of 2009 allocates $19 billion to health information technology, it will be useful for health care managers to project the true cost of implementing an electronic health record (EHR). This study presents a step-by-step guide for using activity-based costing (ABC) to estimate the cost of an EHR. ABC is a cost accounting method with a "top-down" approach for estimating the cost of a project or service within an organization. The total cost to implement an EHR includes obvious costs, such as licensing fees, and hidden costs, such as impact on productivity. Unlike other methods, ABC includes all of the organization's expenditures and is less likely to miss hidden costs. Although ABC is used considerably in manufacturing and other industries, it is a relatively new phenomenon in health care. ABC is a comprehensive approach that the health care field can use to analyze the cost-effectiveness of implementing EHRs. In this article, ABC is applied to a health clinic that recently implemented an EHR, and the clinic is found to be more productive after EHR implementation. This methodology can help health care administrators assess the impact of a stimulus investment on organizational performance.

Characterization of Multilayered Multipass Friction Stir Weld on ASTM A572 G50 Steel

DOE PAGES

Lim, Yong Chae; Sanderson, Samuel; Mahoney, Murray; ...

2014-01-01

A multilayered multipass friction stir weld (MM-FSW) on ASTM A572 Grade 50 steel was characterized to understand its potential application for thick-section structures. The 15-mm-thick section was fabricated by stacking up three steel plates and then friction stir welding the plates together in a total of 5 passes. The unique butt/lap joint configuration encountered in the multilayer weld was examined to understand the effect of tool rotation direction on the joint quality especially the formation of hooking defect. Charpy V-notch impact toughness tests showed generally higher impact toughness energy for the stir zone than the base metal with a ductilemore » fracture mode. The microhardness value was measured from 195 to 220 HV in the stir zone, while the base metal showed an average value of 170 HV. The microstructure in the stir zone and the adjacent heat affected zone was quantified using Optical and Scanning Electron Microscopy (SEM) including Electron Backscatter Diffraction (EBSD). The increased toughness and hardness were correlated with the refined microstructure in stir zone, resulting from severe plastic deformation and subsequent dynamic recrystallization during friction stir welding.« less

Summary of workshop 'Theory Meets Industry'—the impact of ab initio solid state calculations on industrial materials research

NASA Astrophysics Data System (ADS)

Wimmer, E.

2008-02-01

A workshop, 'Theory Meets Industry', was held on 12-14 June 2007 in Vienna, Austria, attended by a well balanced number of academic and industrial scientists from America, Europe, and Japan. The focus was on advances in ab initio solid state calculations and their practical use in industry. The theoretical papers addressed three dominant themes, namely (i) more accurate total energies and electronic excitations, (ii) more complex systems, and (iii) more diverse and accurate materials properties. Hybrid functionals give some improvements in energies, but encounter difficulties for metallic systems. Quantum Monte Carlo methods are progressing, but no clear breakthrough is on the horizon. Progress in order-N methods is steady, as is the case for efficient methods for exploring complex energy hypersurfaces and large numbers of structural configurations. The industrial applications were dominated by materials issues in energy conversion systems, the quest for hydrogen storage materials, improvements of electronic and optical properties of microelectronic and display materials, and the simulation of reactions on heterogeneous catalysts. The workshop is a clear testimony that ab initio computations have become an industrial practice with increasingly recognized impact.

Electron-impact ionization of P-like ions forming Si-like ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwon, D.-H.; Savin, D. W., E-mail: hkwon@kaeri.re.kr

2014-03-20

We have calculated electron-impact ionization (EII) for P-like systems from P to Zn{sup 15+} forming Si-like ions. The work was performed using the flexible atomic code (FAC) which is based on a distorted-wave approximation. All 3ℓ → nℓ' (n = 3-35) excitation-autoionization (EA) channels near the 3p direct ionization threshold and 2ℓ → nℓ' (n = 3-10) EA channels at the higher energies are included. Close attention has been paid to the detailed branching ratios. Our calculated total EII cross sections are compared both with previous FAC calculations, which omitted many of these EA channels, and with the available experimentalmore » results. Moreover, for Fe{sup 11+}, we find that part of the remaining discrepancies between our calculations and recent measurements can be accounted for by the inclusion of the resonant excitation double autoionization process. Lastly, at the temperatures where each ion is predicted to peak in abundances in collisional ionization equilibrium, the Maxwellian rate coefficients derived from our calculations differ by 50%-7% from the previous FAC rate coefficients, with the difference decreasing with increasing charge.« less

Electron-impact coherence parameters for 41 P 1 excitation of zinc

NASA Astrophysics Data System (ADS)

Piwiński, Mariusz; Kłosowski, Łukasz; Chwirot, Stanisław; Fursa, Dmitry V.; Bray, Igor; Das, Tapasi; Srivastava, Rajesh

2018-04-01

We present electron-impact coherence parameters (EICP) for electron-impact excitation of 41 P 1 state of zinc atoms for collision energies 40 eV and 60 eV. The experimental results are presented together with convergent close-coupling and relativistic distorted-wave approximation theoretical predictions. The results are compared and discussed with EICP data for collision energies 80 eV and 100 eV.

Threshold law for electron-atom impact ionization

NASA Technical Reports Server (NTRS)

Temkin, A.

1982-01-01

A derivation of the explicit form of the threshold law for electron impact ionization of atoms is presented, based on the Coulomb-dipole theory. The important generalization is made of using a dipole function whose moment is the dipole moment formed by an inner electron and the nucleus. The result is a modulated quasi-linear law for the yield of positive ions which applies to positron-atom impact ionization.

Electron Impact Excitation-Ionization of Molecules

NASA Astrophysics Data System (ADS)

Ali, Esam Abobakr A.

In the last few decades, the study of atomic collisions by electron-impact has made significant advances. The most difficult case to study is electron impact ionization of molecules for which many approximations have to be made and the validity of these approximations can only be checked by comparing with experiment. In this thesis, I have examined the Molecular three-body distorted wave (M3DW) or Molecular four-body distorted wave (M4DW) approximations for electron-impact ionization. These models use a fully quantum mechanical approach where all particles are treated quantum mechanically and the post collision interaction (PCI) is treated to all orders of perturbation. These electron impact ionization collisions play central roles in the physics and chemistry of upper atmosphere, biofuel, the operation of discharges and lasers, radiation induced damage in biological material like damage to DNA by secondary electrons, and plasma etching processes. For the M3DW model, I will present results for electron impact single ionization of small molecules such as Water, Ethane, and Carbon Dioxide and the much larger molecules Tetrahydrofuran, phenol, furfural, 1-4 Benzoquinone. I will also present results for the four-body problem in which there are two target electrons involved in the collision. M4DW results will be presented for dissociative excitation-ionization of orientated D2. I will show that M4DW calculations using a variational wave function for the ground state that included s- and p- orbital states give better agreement to the experimental measurements than a ground state approximated as a product of two 1s-type Dyson orbitals.

Symptoms and impact of COPD assessed by an electronic diary in patients with moderate-to-severe COPD: psychometric results from the SHINE study.

PubMed

Kulich, Károly; Keininger, Dorothy L; Tiplady, Brian; Banerji, Donald

2015-01-01

Symptoms, particularly dyspnea, and activity limitation, have an impact on the health status and the ability to function normally in patients with chronic obstructive pulmonary disease (COPD). To develop an electronic patient diary (eDiary), qualitative patient interviews were conducted from 2009 to 2010 to identify relevant symptoms and degree of bother due to symptoms. The eDiary was completed by a subset of 209 patients with moderate-to-severe COPD in the 26-week QVA149 SHINE study. Two morning assessments (since awakening and since the last assessment) and one evening assessment were made each day. Assessments covered five symptoms ("shortness of breath," "phlegm/mucus," "chest tightness," "wheezing," and "coughing") and two impact items ("bothered by COPD" and "difficulty with activities") and were scored on a 10-point numeric scale. Patient compliance with the eDiary was 90.4% at baseline and 81.3% at week 26. Correlations between shortness of breath and impact items were >0.95. Regression analysis showed that shortness of breath was a highly significant (P<0.0001) predictor of impact items. Exploratory factor analysis gave a single factor comprising all eDiary items, including both symptoms and impact items. Shortness of breath, the total score (including five symptoms and two impact items), and the five-item symptom score from the eDiary performed well, with good consistency and reliability. The eDiary showed good sensitivity to change, with a 0.6 points reduction in the symptoms scores (on a 0-10 point scale) representing a meaningful change. The eDiary was found to be valid, reliable, and responsive. The high correlations obtained between "shortness of breath" and the ratings of "bother" and "difficulty with activities" confirmed the relevance of this symptom in patients with COPD. Future studies will be required to explore further psychometric properties and their ability to differentiate between COPD treatments.

Electronic excitation of H{sub 2} by electron impact using soft norm-conserving pseudopotentials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Natalense, A.P.; Sartori, C.S.; Ferreira, L.G.

1996-12-01

We calculate electronic excitation cross sections for the {ital b}{sup 3}{Sigma}{sup +}{sub {ital u}} {ital a}{sup 3}{Sigma}{sup +}{sub {ital g}} {ital c}{sup 3}{Pi}{sub {ital u}}, and {ital d}{sup 3}{Pi}{sub {ital u}} states of H{sub 2} by electron impact. Our results were obtained with the Schwinger multichannel method with pseudopotentials and real potentials at the two-channel level of approximation. Pseudo-H atoms are used to generate H{sub 2} molecules with almost the same low-energy spectrum as the real molecules. We show that the dynamics of the electronic excitation process of the pseudomolecules by electron impact is very similar to the real case.more » Our results support the idea that pseudopotentials can be used to obtain reliable molecular electronic excitation cross sections by low-energy electron impact, confirming the expectations of previous studies with CH{sub 2}O [Bettega {ital et} {ital al}., Phys. Rev. A {bold 25}, 1111 (1993)] and HBr [Rescigno, J. Chem. Phys. {bold 104}, 125 (1996)]. {copyright} {ital 1996 The American Physical Society.}« less

Ionospheric variation observed in Oregon Real-time GNSS network during the total eclipse of 21 August 2017

NASA Astrophysics Data System (ADS)

Shahbazi, A.; Park, J.; Kim, S.; Oberg, R.

2017-12-01

As the ionospheric behavior is highly related to the solar activity, the total eclipse passing across the North America on 21 August 2017 is expected to significantly affect the electron density in the ionosphere along the path. Taking advantage of GNSS capability for observing total electron content (TEC), this study demonstrates the impact of the total eclipse not only on the TEC variation during the period of the event but also on GNSS positioning. Oregon Department of Transportation (ODOT) runs a dense real time GNSS network, referred to as Oregon Real-time GNSS network (ORGN). From the dual frequency GPS and GLONASS observations in ORGN, the TEC over the network area can be extracted. We observe the vertical TEC (VTEC) from the ORGN for analyzing the ionospheric condition in the local area affected by the eclipse. To observe the temporal variation, we also observe the slant TEC (STEC) in each ray path and analyze the short term variation in different geometry of each ray path. Although the STEC is dependent quantity upon the changing geometry of a satellite, this approach provides insight to the ionospheric behavior of the total eclipse because the STEC does not involve the projection error, which is generated by VTEC computation. During the period of eclipse, the abnormal variations on VTEC and STEC are expected. The experimental results will be presented in time series plots for selected stations as well as the regional TEC map in Oregon. In addition to the TEC monitoring, we also test the positioning result of ORGN stations through Precise Point Positioning (PPP) and relative positioning. The expected result is that the both positioning results are degraded during the solar eclipse due to the instable ionospheric condition over short time.

How are the kids holding up? A systematic review and meta-analysis on the psychosocial impact of maternal breast cancer on children.

PubMed

Purc-Stephenson, Rebecca; Lyseng, Annelise

2016-09-01

Having a mother diagnosed with breast cancer can be a distressing time for a child. This review examines the impact maternal breast cancer has on the psychosocial functioning of children and what factors possibly moderate this relationship. Using PRISMA guidelines, five electronic databases were systematically searched for published studies examining maternal breast cancer and the psychosocial functioning of children. A total of 15 studies contributed to the analysis. Results from a random effects meta-analysis show that children experience marginally elevated internalizing problems (standardized mean difference=.14, 95% CI .00, .28), significantly fewer total problem behaviors (standardized mean difference=-.13, 95% CI -.23, -.03), and no changes in externalizing problems (standardized mean difference=-.07, 95% CI -.19, .05) relative to comparison groups. Consistent with this, the narrative review suggests the children may experience elevated depression, anxiety and mental distress yet show more social competence and little aggressive or disruptive behavior. Significant moderating variables included informant type (i.e., self-ratings vs mother's ratings vs other's ratings) and comparison group used (i.e., controls vs normative data). There is also evidence that illness severity and maternal mental health may impact the results. The results suggest that children may be at risk for internalizing-type problems, especially when their mother experiences depression and has serious medical complications. Research using larger and more diverse samples is needed to fully understand how maternal breast cancer impacts children. Copyright © 2016 Elsevier Ltd. All rights reserved.

TURBULENCE AND PROTON–ELECTRON HEATING IN KINETIC PLASMA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matthaeus, William H; Parashar, Tulasi N; Wu, P.

2016-08-10

Analysis of particle-in-cell simulations of kinetic plasma turbulence reveals a connection between the strength of cascade, the total heating rate, and the partitioning of dissipated energy into proton heating and electron heating. A von Karman scaling of the cascade rate explains the total heating across several families of simulations. The proton to electron heating ratio increases in proportion to total heating. We argue that the ratio of gyroperiod to nonlinear turnover time at the ion kinetic scales controls the ratio of proton and electron heating. The proposed scaling is consistent with simulations.

Sediment matrix characterization as a tool for evaluating the environmental impact of heavy metals in metal mining, smelting, and ore processing areas.

PubMed

Ružičková, Silvia; Remeteiová, Dagmar; Mičková, Vladislava; Dirner, Vojtech

2018-02-21

In this work, the matrix characterization (mineralogy, total and local chemical composition, and total organic (TOC) and inorganic carbon (TIC) contents) of different types of sediments from mining- and metallurgy-influenced areas and the assessment of the impact of the matrix on the association of potentially hazardous metals with the mineral phases of these samples, which affect their mobility in the environment, are presented. For these purposes, sediment samples with different origins and from different locations in the environment were analyzed. Anthropogenic sediments from metal-rich post-flotation tailings (Lintich, Slovakia) represent waste from ore processing, natural river sediments from the Hornád River (Košice, Slovakia) represent areas influenced predominantly by the metallurgical industry, and lake sediments from a water reservoir Ružín (inflow from the Hornád and Hnilec Rivers, Slovakia) represent the impact of the metallurgical and/or mining industries. The total metal contents were determined by X-ray fluorescence (XRF) analysis, the local chemical and morphological microanalysis by scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), and the TOC and TIC contents by infrared (IR) spectrometry. The mobility/bioavailability of Cu, Pb, and Zn in/from sediments at the studied areas was assessed by ethylenediaminetetraacetic acid (EDTA) and acetic acid (AA) extraction and is discussed in the context of the matrix composition. The contents of selected potentially hazardous elements in the extracts were determined by the high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS).

Electron impact action spectroscopy of mass/charge selected macromolecular ions: Inner-shell excitation of ubiquitin protein

DOE PAGES

Rankovic, Milos Lj.; Giuliani, Alexandre; Milosavljevic, Aleksandar R.

2016-02-11

In this study, we have performed inner-shell electron impact action spectroscopy of mass and charge selected macromolecular ions. For this purpose, we have coupled a focusing electron gun with a linear quadrupole ion trap mass spectrometer. This experiment represents a proof of principle that an energy-tunable electron beam can be used in combination with radio frequency traps as an activation method in tandem mass spectrometry (MS 2) and allows performing action spectroscopy. Electron impact MS 2 spectra of multiply protonated ubiquitin protein ion have been recorded at incident electron energies around the carbon 1s excitation. Both MS 2 and singlemore » ionization energy dependence spectra are compared with literature data obtained using the soft X-ray activation conditions.« less

Electron impact action spectroscopy of mass/charge selected macromolecular ions: Inner-shell excitation of ubiquitin protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rankovic, Milos Lj.; Giuliani, Alexandre; Milosavljevic, Aleksandar R.

In this study, we have performed inner-shell electron impact action spectroscopy of mass and charge selected macromolecular ions. For this purpose, we have coupled a focusing electron gun with a linear quadrupole ion trap mass spectrometer. This experiment represents a proof of principle that an energy-tunable electron beam can be used in combination with radio frequency traps as an activation method in tandem mass spectrometry (MS 2) and allows performing action spectroscopy. Electron impact MS 2 spectra of multiply protonated ubiquitin protein ion have been recorded at incident electron energies around the carbon 1s excitation. Both MS 2 and singlemore » ionization energy dependence spectra are compared with literature data obtained using the soft X-ray activation conditions.« less

Differential cross sections for the electron impact ionization of Ar (3 p) atoms for equal energy final state electrons

NASA Astrophysics Data System (ADS)

Purohit, Ghanshyam; Singh, Prithvi

2017-06-01

The electron-impact ionization of inert gases for asymmetric final state energy sharing conditions has been studied in detail. However, there have been relatively few studies examining equal energy final state electrons. We report in this communication the results of triple differential cross sections (TDCSs) for electron impact ionization of Ar (3 p) for equal energy sharing of the outgoing electrons. We calculate TDCS in the modified distorted wave Born approximation (DWBA) formalism including post collision interaction (PCI) and polarization potential. We compare the results of our calculation with available measurements [Phys. Rev. A 87, 022712 (2013)]. We study the effect of PCI, target polarization on the trends of TDCS for the single ionization of Ar (3 p) targets.

Concerning sources of O/1D/ in Aurora - Electron impact and dissociative recombination

NASA Technical Reports Server (NTRS)

Sharp, W. E.; Ortland, D.; Cageao, R.

1983-01-01

The present investigation is concerned with two questions. One is related to the possibility that the O(1D) level is produced by an as yet unidentified process in aurora. The second question is concerned with the need for an additional source and the altitude over which it is required. The data base of the AE satellite (AE-D in particular) was examined for this study. It is found that dissociative recombination and electron impact are inadequate sources of O(1D) in aurora. Nearly 90% of the source function is unidentified below 200 km and about 55% is missing above 250 km. The possibility that thermal electron impact could provide the missing source above 250 km was examined. Calculations showed that the missing source above 250 km could be explained by thermal electron impact if the electron temperatures were approximately 2900 K.

Venus nightside ionosphere - A model with KeV electron impact ionization

NASA Technical Reports Server (NTRS)

Kumar, S.

1982-01-01

The impact of keV electrons is proposed as the strongest source of ionization in a full-up Venus nightside ionosphere model for the equatorial midnight region. The electron impacts lead to a peak ion density of 100,000/cu cm, which was observed by the PV-OIMS experiment on several occasions. In addition, the observed altitude profiles of CO2(+), O(+), O2(+), H(+), and H2(+) can be reproduced by the model on condition that the available keV electron flux is approximated by a reasonable extrapolation from fluxes observed at lower energies.

A coincidence study of electron and positron impact ionization of Ar (3p) at 1 keV

NASA Astrophysics Data System (ADS)

Campeanu, Radu I.; Walters, James H. R.; Whelan, Colm T.

2015-10-01

Distorted-wave calculations of the triple differential cross section (TDCS) are presented for electron and positron impact ionization of Ar(3p) in coplanar asymmetric geometry at an impact energy of 1 keV and are compared with a recent experiment. The experiment indicates that the positron TDCS is generally larger than the equivalent electron TDCS. It is shown that the magnitude of the TDCS is extremely sensitive to the energy of the ejected electron and that only when the cross section is averaged over energy do we get a reasonable agreement with experiment.

Treatment of Electronic Energy Level Transition and Ionization Following the Particle-Based Chemistry Model

NASA Technical Reports Server (NTRS)

Liechty, Derek S.; Lewis, Mark

2010-01-01

A new method of treating electronic energy level transitions as well as linking ionization to electronic energy levels is proposed following the particle-based chemistry model of Bird. Although the use of electronic energy levels and ionization reactions in DSMC are not new ideas, the current method of selecting what level to transition to, how to reproduce transition rates, and the linking of the electronic energy levels to ionization are, to the author s knowledge, novel concepts. The resulting equilibrium temperatures are shown to remain constant, and the electronic energy level distributions are shown to reproduce the Boltzmann distribution. The electronic energy level transition rates and ionization rates due to electron impacts are shown to reproduce theoretical and measured rates. The rates due to heavy particle impacts, while not as favorable as the electron impact rates, compare favorably to values from the literature. Thus, these new extensions to the particle-based chemistry model of Bird provide an accurate method for predicting electronic energy level transition and ionization rates in gases.

Photoionization and electron-impact ionization of Ar5+

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, J.C.; Lu, M.; Esteves, D.

2007-02-27

Absolute cross sections for photoionization andelectron-impact Photionization of Ar5+ have been measuredusing twodifferent interacting-beams setups. The spectra consist of measurementsof the yield of products dueto single ionization as a function ofelectron or photon energy. In addition, absolute photoionization andelectron-impact ionization cross sections were measured to normalize themeasured Ar6+ product-ion yield spectra. In the energy range from 90 to111 eV, both electron-impact ionization and photoionization of Ar5+aredominated by indirect 3s subshell excitation-autoionization. In theenergy range from 270 to 285 eV, resonances due to 2p-3dexcitation-autoionization are prominent in the photoionization spectrum.In the range from 225 to 335 eV, an enhancement due tomore » 2p-nl (n>2>excitations are evident in the electron-impactionization cross section.The electron and photon impact data show some features due to excitationof the same intermediate autoionizing states.« less

Impact of decision support in electronic medical records on lipid management in primary care.

PubMed

Gill, James M; Chen, Ying Xia; Glutting, Joseph J; Diamond, James J; Lieberman, Michael I

2009-10-01

Electronic decision-support tools may help to improve management of hyperlipidemia and other chronic diseases. This study examined the impact of lipid management tools integrated into an electronic medical record (EMR) in primary care practices. This randomized controlled trial was conducted in a national network of physicians who use an outpatient EMR. Adult primary care physicians were randomized by office to receive an electronic form that was embedded in the EMR. The form contained prompts regarding suboptimal care based on Adult Treatment Panel-III (ATP-III) guidelines, as well as reporting tools to identify patients outside of office visits whose lipid management was suboptimal. All active patients, ages 20-79 years, whose physicians participated in the study, were categorized as high, moderate, or low cardiovascular risk, and the proportion who were tested for hyperlipidemia, at lipid goal, and on lipid-lowering medications if not at goal were measured according to ATP-III guidelines. A total of 105 physicians from 25 offices and 64,150 patients were included in the study. Outcomes improved for most measures from before to 1 year after the intervention (November 1, 2005 to October 31, 2006). However, after controlling for confounding variables and for clustering in multilevel modeling, only up-to-date lipid testing for high-risk patients was statistically better in the intervention group as compared to the control group (adjusted odds ratio 15.0, P < 0.05). This study showed few differences in quality of lipid management after implementing an EMR-based disease management intervention in primary care settings. Future studies may need to examine more comprehensive interventions that include office staff in a team approach to care.

Non-inductive current generation in fusion plasmas with turbulence

NASA Astrophysics Data System (ADS)

Wang, Weixing; Ethier, S.; Startsev, E.; Chen, J.; Hahm, T. S.; Yoo, M. G.

2017-10-01

It is found that plasma turbulence may strongly influence non-inductive current generation. This may have radical impact on various aspects of tokamak physics. Our simulation study employs a global gyrokinetic model coupling self-consistent neoclassical and turbulent dynamics with focus on electron current. Distinct phases in electron current generation are illustrated in the initial value simulation. In the early phase before turbulence develops, the electron bootstrap current is established in a time scale of a few electron collision times, which closely agrees with the neoclassical prediction. The second phase follows when turbulence begins to saturate, during which turbulent fluctuations are found to strongly affect electron current. The profile structure, amplitude and phase space structure of electron current density are all significantly modified relative to the neoclassical bootstrap current by the presence of turbulence. Both electron parallel acceleration and parallel residual stress drive are shown to play important roles in turbulence-induced current generation. The current density profile is modified in a way that correlates with the fluctuation intensity gradient through its effect on k//-symmetry breaking in fluctuation spectrum. Turbulence is shown to deduct (enhance) plasma self-generated current in low (high) collisionality regime, and the reduction of total electron current relative to the neoclassical bootstrap current increases as collisionality decreases. The implication of this result to the fully non-inductive current operation in steady state burning plasma regime should be investigated. Finally, significant non-inductive current is observed in flat pressure region, which is a nonlocal effect and results from turbulence spreading induced current diffusion. Work supported by U.S. DOE Contract DE-AC02-09-CH11466.

Measurement of Nuclear Recoils in the CDMS II Dark Matter Search

NASA Astrophysics Data System (ADS)

Fallows, Scott M.

The Cryogenic Dark Matter Search (CDMS) experiment is designed to directly detect elastic scatters of weakly-interacting massive dark matter particles (WIMPs), on target nuclei in semiconductor crystals composed of Si and Ge. These scatters would occur very rarely, in an overwhelming background composed primarily of electron recoils from photons and electrons, as well as a smaller but non-negligible background of WIMP-like nuclear recoils from neutrons. The CDMS~II generation of detectors simultaneously measure ionization and athermal phonon signals from each scatter, allowing discrimination against virtually all electron recoils in the detector bulk. Pulse-shape timing analysis allows discrimination against nearly all remaining electron recoils taking place near detector surfaces. Along with carefully limited neutron backgrounds, this experimental program allowed for "background-free'' operation of CDMS~II at Soudan, with less than one background event expected in each WIMP-search analysis. As a result, exclusionary upper-limits on WIMP-nucleon interaction cross section were placed over a wide range of candidate WIMP masses, ruling out large new regions of parameter space. These results, like any others, are subject to a variety of systematic effects that may alter their final interpretations. A primary focus of this dissertation will be difficulties in precisely calibrating the energy scale for nuclear recoil events like those from WIMPs. Nuclear recoils have suppressed ionization signals relative to electron recoils of the same recoil energy, so the response of the detectors is calibrated differently for each recoil type. The overall normalization and linearity of the energy scale for electron recoils in CDMS~II detectors is clearly established by peaks of known gamma energy in the ionization spectrum of calibration data from a 133Ba source. This electron-equivalent keVee) energy scale enables calibration of the total phonon signal (keVt) by enforcing unity yield for electron recoils, in aggregate. Subtracting an event's Luke phonon contribution from its calibrated total phonon energy (keV t), as measured by the ionization signal, results in a valid measure of the true recoil energy (keVr) for both electron and nuclear recoils. I discuss systematic uncertainties affecting the reconstruction of this recoil energy, the primary analysis variable, and use several methods to constrain their magnitude. I present the resulting adjusted WIMP limits and discuss their impact in the context of current and projected constraints on the parameter space for WIMP interactions.

Radiation Testing and Evaluation Issues for Modern Integrated Circuits

NASA Technical Reports Server (NTRS)

LaBel, Kenneth A.; Cohn, Lew M.

2005-01-01

Abstract. Changes in modern integrated circuit (IC) technologies have modified the way we approach and conduct radiation tolerance and testing of electronics. These changes include scaling of geometries, new materials, new packaging technologies, and overall speed and device complexity challenges. In this short course section, we will identify and discuss these issues as they impact radiation testing, modeling, and effects mitigation of modern integrated circuits. The focus will be on CMOS-based technologies, however, other high performance technologies will be discussed where appropriate. The effects of concern will be: Single-Event Effects (SEE) and steady state total ionizing dose (TID) IC response. However, due to the growing use of opto-electronics in space systems issues concerning displacement damage testing will also be considered. This short course section is not intended to provide detailed "how-to-test" information, but simply provide a snapshot of current challenges and some of the approaches being considered.

Coordinate space translation technique for simulation of electronic process in the ion-atom collision.

PubMed

Wang, Feng; Hong, Xuhai; Wang, Jian; Kim, Kwang S

2011-04-21

Recently we developed a theoretical model of ion-atom collisions, which was made on the basis of a time-dependent density functional theory description of the electron dynamics and a classical treatment of the heavy particle motion. Taking advantage of the real-space grid method, we introduce a "coordinate space translation" technique to allow one to focus on a certain space of interest such as the region around the projectile or the target. Benchmark calculations are given for collisions between proton and oxygen over a wide range of impact energy. To extract the probability of charge transfer, the formulation of Lüdde and Dreizler [J. Phys. B 16, 3973 (1983)] has been generalized to ensemble-averaging application in the particular case of O((3)P). Charge transfer total cross sections are calculated, showing fairly good agreements between experimental data and present theoretical results.

Dissociative-ionization cross sections for 12-keV-electron impact on CO{sub 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhatt, Pragya; Singh, Raj; Yadav, Namita

The dissociative ionization of a CO{sub 2} molecule is studied at an electron energy of 12 keV using the multiple ion coincidence imaging technique. The absolute partial ionization cross sections and the precursor-specific absolute partial ionization cross sections of resulting fragment ions are obtained and reported. It is found that {approx}75% of single ionization, 22% of double ionization, and {approx}2% of triple ionization of the parent molecule contribute to the total fragment ion yield; quadruple ionization of CO{sub 2} is found to make a negligibly small contribution. Furthermore, the absolute partial ionization cross sections for ion-pair and ion-triple formation aremore » measured for nine dissociative ionization channels of up to a quadruply ionized CO{sub 2} molecule. In addition, the branching ratios for single-ion, ion-pair, and ion-triple formation are also determined.« less

Menstrual problems in university students: an electronic mail survey.

PubMed

Anastasakis, E; Kingman, C E; Lee, C A; Economides, D L; Kadir, R A

2008-01-01

To establish the prevalence of menstrual-related problems among university students. A questionnaire regarding gynecological, bleeding and family history was sent by electronic mail (e-mail) to all female students attending University College London (UCL). A total of 767 students aged 18-39 years replied; 71% had a regular menstrual cycle. One in three (n = 264) had received some treatment for their menstrual periods (such as the combined oral contraceptive pill or simple analgesia). Those with heavy or painful periods were more likely to feel that their menstrual problems had a substantial impact on their academic and social life; however, even among those with light periods, one in every four females felt that their life was considerably affected. A considerable prevalence of menstrual-related problems was demonstrated among this young healthy population. Additionally, the use of e-mail could present potential benefits as a research medium for this kind of study.

Many-electron aspects of molecular promotion in ion-atom collisions - Production of core-excited states of Li in Li/+/-He collisions

NASA Technical Reports Server (NTRS)

Elston, S. B.; Vane, C. R.; Schumann, S.

1979-01-01

Production of core-excited autoionizing states of neutral Li having configurations of the form 1snln(prime)l(prime) has been observed over the impact-energy range from 10-50 keV. Although the results for production of all such states is remarkably consistent with a quasi-molecular-excitation model proposed by Stolterfoht and Leithaeuser (1976), production of individual lines in the observed spectra exhibits collision-velocity dependencies indicative of considerably more complex processes, including processes which appear to be inherently two-electron in nature. Excitation functions are presented for (1s2s/2/)/2/S, 1s(2s2p/3/P)/2/P, 1s(2s2p/1/P)/2/P, and (1s2p/2/)/2/D core-excited state of Li and for total core excitation.

A novel membrane distillation-thermophilic bioreactor system: biological stability and trace organic compound removal.

PubMed

Wijekoon, Kaushalya C; Hai, Faisal I; Kang, Jinguo; Price, William E; Guo, Wenshan; Ngo, Hao H; Cath, Tzahi Y; Nghiem, Long D

2014-05-01

The removal of trace organic compounds (TrOCs) by a novel membrane distillation-thermophilic bioreactor (MDBR) system was examined. Salinity build-up and the thermophilic conditions to some extent adversely impacted the performance of the bioreactor, particularly the removal of total nitrogen and recalcitrant TrOCs. While most TrOCs were well removed by the thermophilic bioreactor, compounds containing electron withdrawing functional groups in their molecular structure were recalcitrant to biological treatment and their removal efficiency by the thermophilic bioreactor was low (0-53%). However, the overall performance of the novel MDBR system with respect to the removal of total organic carbon, total nitrogen, and TrOCs was high and was not significantly affected by the conditions of the bioreactor. All TrOCs investigated here were highly removed (>95%) by the MDBR system. Biodegradation, sludge adsorption, and rejection by MD contribute to the removal of TrOCs by MDBR treatment. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Assessing ionospheric response during some strong storms in solar cycle 24 using various data sources

NASA Astrophysics Data System (ADS)

Habarulema, John Bosco; Katamzi, Zama Thobeka; Sibanda, Patrick; Matamba, Tshimangadzo Merline

2017-01-01

We present an analysis of a regional ionospheric response during six strong storms (-200 nT ≤Dst≤-100 nT) that occurred in 2012 for the geographic latitudinal coverage of 10°S-40°S within a longitude sector of 10°E-40°E. Although these storms occurred during the same solar activity period and were all coronal mass ejection driven, their impacts and associated features on the ionosphere have been found different due to different contributing factors to their driving mechanisms. With the exception of one case, the rest of the storm periods were characterized by positive storm effects during the main and (or) recovery phases with varying physical mechanisms including low-latitude electrodynamics, neutral composition changes, and traveling ionospheric disturbances (TIDs). The common result to all the analyzed strong storms was the presence of large-scale TIDs during the storm main phases. Using total electron content data derived from the Global Navigational Satellite System (GNSS) observations and radio occultation (RO) electron density data on a regional scale, we have attempted to investigate meridional and vertical propagation of TIDs simultaneously during the strong storms. We have showed that it is possible to identify vertical motion of TIDs using RO data in cases when equatorward TIDs, as revealed by GNSS total electron content data, are present. RO results were compared to ionosonde data, and both data sources gave vertical velocities below 100 m/s of the associated TIDs.

Cost of Behavioral Interventions Utilizing Electronic Drug Monitoring for Antiretroviral Therapy Adherence

PubMed Central

Rasu, Rafia S.; Malewski, David F.; Banderas, Julie W.; Thomson, Domonique Malomo; Goggin, Kathy

2013-01-01

Objective To provide data on the actual costs associated with behavioral ART adherence interventions and electronic drug monitoring used in a clinical trial to inform their implementation in future studies and real-world practice. Methods Direct and time costs were calculated from a multi-site three-arm randomized controlled ART adherence trial. HIV positive participants (n = 204) were randomized to standard care (SC), enhanced counseling (EC), or EC and modified directly observed therapy (mDOT) interventions. Electronic drug monitoring (EDM) was used. Costs were calculated for various components of the 24-week adherence intervention. This economic evaluation was conducted from the perspective of an agency that may wish to implement these strategies. Sensitivity analyses were conducted to examine costs and savings associated with different scenarios. Results Total direct costs were $126,068 ($618/patient). Initial time costs were $53,590 ($262/patient). Base cost of labor was $0.36/minute. EC costs for 134 patients were $18,427 ($137/patient) and mDOT for 64 patients cost $18,638 ($291/patient). Total per patient costs were: SC=$880, EC=$1,018, EC/mDOT=$1,309. Removing driving costs evidenced the most variable impact on savings between the three study arms. The tornado diagram (sensitivity analysis) showed a graphical representation of how each sensitivity assumption reduced costs compared to each other and the resulting comparative costs for each group. Conclusion This novel economic analysis provides valuable cost information to guide treatment implementation and research design decisions. PMID:23337364

Jupiter's Auroral Energy Input Observed by Hisaki/EXCEED and its Modulations by Io's Volcanic Activity

NASA Astrophysics Data System (ADS)

Tao, C.; Kimura, T.; Tsuchiya, F.; Murakami, G.; Yoshioka, K.; Kita, H.; Yamazaki, A.; Kasaba, Y.; Yoshikawa, I.; Fujimoto, M.

2016-12-01

Aurora is an important indicator representing the momentum transfer from the fast-rotating outer planet to the magnetosphere and the energy input into the atmosphere through the magnetosphere-ionosphere coupling. Long-term monitoring of Jupiter's northern aurora was achieved by the Extreme Ultraviolet (EUV) spectrometer called EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics) onboard JAXA's Earth-orbiting planetary space telescope Hisaki until today after its launch in September 2013. We have proceeded the statistical survey of the Jupiter's auroral energy input into the upper atmosphere. The auroral electron energy is estimated using a hydrocarbon color ratio (CR) adopted for the wavelength range of EXCEED, and the emission power in the long wavelength range 138.5-144.8 nm is used as an indicator of total emitted power before hydrocarbon absorption and auroral electron energy flux. Temporal dynamic variation of the auroral intensity was detected when Io's volcanic activity and thus EUV emission from the Io plasma torus are enhanced in the early 2015. Average of the total input power over 80 days increases by 10% with sometimes sporadically more than a factor of 3 upto 7, while the CR indicates the auroral electron energy decrease by 20% during the volcanic event compared to the other period. This indicates much more increase in the current system and Joule heating which contributes heating of the upper atmosphere. We will discuss the impact of this event on the upper atmosphere and ionosphere.

A unitary convolution approximation for the impact-parameter dependent electronic energy loss

NASA Astrophysics Data System (ADS)

Schiwietz, G.; Grande, P. L.

1999-06-01

In this work, we propose a simple method to calculate the impact-parameter dependence of the electronic energy loss of bare ions for all impact parameters. This perturbative convolution approximation (PCA) is based on first-order perturbation theory, and thus, it is only valid for fast particles with low projectile charges. Using Bloch's stopping-power result and a simple scaling, we get rid of the restriction to low charge states and derive the unitary convolution approximation (UCA). Results of the UCA are then compared with full quantum-mechanical coupled-channel calculations for the impact-parameter dependent electronic energy loss.

PHD TUTORIAL: A complete numerical approach to electron hydrogen collisions

NASA Astrophysics Data System (ADS)

Bartlett, Philip L.

2006-11-01

This tutorial presents an extensive computational study of electron-impact scattering and ionization of atomic hydrogen and hydrogenic ions, through the solution of the non-relativistic Schrödinger equation in coordinate space using propagating exterior complex scaling (PECS). It details the complete numerical and computational development of the PECS method, which enables highly computationally-efficient solution of these collision systems. Benchmark results are presented for a complete range of electron-hydrogen collisions, including discrete elastic and inelastic scattering both below and above the ionization threshold energy, very low-energy ionizing collisions through to moderately high-energy ionizing collisions, ground-state and excited-state targets and charged hydrogenic targets with Z <= 4. Total ionization cross sections through to fully differential cross sections, both in-plane and out-of-plane, are given and are found to be in excellent accord with other state-of-the-art methods and measurements, where available. We also review our recent confirmation (Bartlett and Stelbovics 2004 Phys. Rev. Lett. 93 233201) of the Wannier and related threshold laws for e-H collisions.

First-principles study of intermediate-spin ferrous iron in the Earth's lower mantle

NASA Astrophysics Data System (ADS)

Hsu, Han; Wentzcovitch, Renata M.

2014-11-01

Spin crossover of iron is of central importance in solid Earth geophysics. It impacts all physical properties of minerals that altogether constitute ˜95 vol% of the Earth's lower mantle: ferropericlase [(Mg,Fe)O] and Fe-bearing magnesium silicate (MgSiO3) perovskite. Despite great strides made in the past decade, the existence of an intermediate-spin (IS) state in ferrous iron (Fe2 +) (with total electron spin S =1 ) and its possible role in the pressure-induced spin crossover in these lower-mantle minerals still remain controversial. Using density functional theory + self-consistent Hubbard U (DFT+Usc ) calculations, we investigate all possible types of IS states of Fe2 + in (Mg,Fe)O and (Mg,Fe)SiO3 perovskite. Among the possible IS states in these minerals, the most probable IS state has an electronic configuration that significantly reduces the electron overlap and the iron nuclear quadrupole splitting (QS). These most probable IS states, however, are still energetically disfavored, and their QSs are inconsistent with Mössbauer spectra. We therefore conclude that IS Fe2 + is highly unlikely in the Earth's lower mantle.

The spectrum of the Jovian dayglow observed at 3 A resolution with the Hopkins ultraviolet telescope

NASA Technical Reports Server (NTRS)

Feldman, P. D.; Mcgrath, M. A.; Moos, H. W.; Durrance, S. T.; Strobel, D. F.; Davidsen, A. F.

1993-01-01

Ultraviolet spectra of the Jovian equatorial dayglow in the spectral range 830-1850 A were obtained at about 3 A resolution. The observed spectrum is dominated by electron impact excitation of the H2 Lyman and Werner band systems. Solar Lyman-beta induced fluorescence in the (6, nu-double prime) Lyman band progression is clearly identified in five distinct P(1) lines, and the contribution of solar fluorescence to the total 2.3 kR slit-averaged H2 emission rate is estimated to be 17-22 percent. The electron excitation spectrum is characterized by a relative weakness of the Werner band system and the absence of cascade contributions to the Lyman system and is very similar to that of the south polar aurora. The integrated H2 emission rate in the 900-1100 A band is a factor of two lower than that measured by the Voyager UVS. Based on model calculations, photoelectron excitation does not appear able to account for the amount of observed electron-excited H2 emission.

Electron Driven Processes in Atmospheric Behaviour

NASA Astrophysics Data System (ADS)

Campbell, L.; Brunger, M. J.; Teubner, P. J. O.

2006-11-01

Electron impact plays an important role in many atmospheric processes. Calculation of these is important for basic understanding, atmospheric modeling and remote sensing. Accurate atomic and molecular data, including electron impact cross sections, are required for such calculations. Five electron-driven processes are considered: auroral and dayglow emissions, the reduction of atmospheric electron density by vibrationally excited N2, NO production and infrared emission from NO. In most cases the predictions are compared with measurements. The dependence on experimental atomic and molecular data is also investigated.

A distorted-wave methodology for electron-ion impact excitation - Calculation for two-electron ions

NASA Technical Reports Server (NTRS)

Bhatia, A. K.; Temkin, A.

1977-01-01

A distorted-wave program is being developed for calculating the excitation of few-electron ions by electron impact. It uses the exchange approximation to represent the exact initial-state wavefunction in the T-matrix expression for the excitation amplitude. The program has been implemented for excitation of the 2/1,3/(S,P) states of two-electron ions. Some of the astrophysical applications of these cross sections as well as the motivation and requirements of the calculational methodology are discussed.

Electron impact excitation of SO2 - Differential, integral, and momentum transfer cross sections

NASA Technical Reports Server (NTRS)

Vuskovic, L.; Trajmar, S.

1982-01-01

Electron impact excitation of the electronic states of SO2 was investigated. Differential, integral, and inelastic momentum transfer cross sections were obtained by normalizing the relative measurements to the elastic cross sections. The cross sections are given for seven spectral ranges of the energy-loss spectra extending from the lowest electronic state to near the first ionization limit. Most of the regions represent the overlap of several electronic transitions. No measurements for these cross sections have been reported previously.

Electronic whiteboards: review of the literature.

PubMed

Randell, Rebecca; Greenhalgh, Joanne; Wyatt, Jeremy; Gardner, Peter; Pearman, Alan; Honey, Stephanie; Dowding, Dawn

2015-01-01

Electronic whiteboards are being introduced into hospitals to communicate real-time patient information instantly to staff. This paper provides a preliminary review of the current state of evidence for the effect of electronic whiteboards on care processes and patient outcomes. A literature search was performed for the dates 1996 to 2014 on MEDLINE, EMBASE, IEEE Xplore, Science Direct, and the ACM Digital Library. Thirteen papers, describing 11 studies, meeting the inclusion criteria were identified. The majority of studies took place in the Emergency Department. While studies looked at the impact of electronic whiteboards on the process of care, there is an absence of evidence concerning impact on patient outcomes. There is a need for robust research measuring the impact of electronic whiteboards on inpatient care.

Impact of Electronic Portfolios on Prospective Teachers' Participation, Motivation, and Autonomous Learning

ERIC Educational Resources Information Center

Gámiz-Sánchez, Vanesa-María; Gallego-Arrufat, María-Jesús; Crisol-Moya, Emilio

2016-01-01

This study explores the impact of electronic portfolios on undergraduate learning in higher education. Based on a descriptive study, it analyses the prospective teacher's perception of use of these tools (electronic portfolio in Moodle-Mahara, in the institutional environment of a university in southern Europe), examining the variables…

The Pervasiveness and Impact of Electronic Communication Technologies in Organizations: A Survey of Major American Corporations.

ERIC Educational Resources Information Center

Hellweg, Susan A.; And Others

A survey of the Fortune 500 corporations was conducted to ascertain the pervasiveness and perceived impact of five electronic communication technologies (electronic mail, videotex, interactive computers, video teleconferencing, and word processing). Ninety-four corporations responded to a 53-item questionnaire and follow-up survey. Analysis of the…

Identification of biomedical journals in Spain and Latin America.

PubMed

Bonfill, Xavier; Osorio, Dimelza; Posso, Margarita; Solà, Ivan; Rada, Gabriel; Torres, Ania; García Dieguez, Marcelo; Piña-Pozas, Maricela; Díaz-García, Luisa; Tristán, Mario; Gandarilla, Omar; Rincón-Valenzuela, David A; Martí, Arturo; Hidalgo, Ricardo; Simancas-Racines, Daniel; López, Luis; Correa, Ricardo; Rojas-De-Arias, Antonieta; Loza, César; Gianneo, Óscar; Pardo, Hector

2015-12-01

Journals in languages other than English that publish original clinical research are often not well covered in the main biomedical databases and therefore often not included in systematic reviews. This study aimed to identify Spanish language biomedical journals from Spain and Latin America and to describe their main features. Journals were identified in electronic databases, publishers' catalogues and local registries. Eligibility was determined by assessing data from these sources or the journals' websites, when available. A total of 2457 journals were initially identified; 1498 met inclusion criteria. Spain (27.3%), Mexico (16.0%), Argentina (15.1%) and Chile (11.9%) had the highest number of journals. Most (85.8%) are currently active; 87.8% have an ISSN. The median and mean length of publication were 22 and 29 years, respectively. A total of 66.0% were indexed in at least one database; 3.0% had an impact factor in 2012. A total of 845 journals had websites (56.4%), of which 700 (82.8%) were searchable and 681 (80.6%) free of charge. Most of the identified journals have no impact factor or are not indexed in any of the major databases. The list of identified biomedical journals can be a useful resource when conducting hand searching activities and identifying clinical trials that otherwise would not be retrieved. © 2015 Health Libraries Group.

Mandibular Third Molar Impaction: Review of Literature and a Proposal of a Classification

PubMed Central

Daugela, Povilas

2013-01-01

ABSTRACT Objectives The purpose of present article was to review impacted mandibular third molar aetiology, clinical anatomy, radiologic examination, surgical treatment and possible complications, as well as to create new mandibular third molar impaction and extraction difficulty degree classification based on anatomical and radiologic findings and literature review results. Material and Methods Literature was selected through a search of PubMed, Embase and Cochrane electronic databases. The keywords used for search were mandibular third molar, impacted mandibular third molar, inferior alveolar nerve injury third molar, lingual nerve injury third molar. The search was restricted to English language articles, published from 1976 to April 2013. Additionally, a manual search in the major anatomy and oral surgery journals and books was performed. The publications there selected by including clinical and human anatomy studies. Results In total 75 literature sources were obtained and reviewed. Impacted mandibular third molar aetiology, clinical anatomy, radiographic examination, surgical extraction of and possible complications, classifications and risk factors were discussed. New mandibular third molar impaction and extraction difficulty degree classification based on anatomical and radiologic findings and literature review results was proposed. Conclusions The classification proposed here based on anatomical and radiological impacted mandibular third molar features is promising to be a helpful tool for impacted tooth assessment as well as for planning for surgical operation. Further clinical studies should be conducted for new classification validation and reliability evaluation. PMID:24422029

Investigation of the Electron Density Variation During the 21 August 2017 Solar Eclipse

NASA Astrophysics Data System (ADS)

Reinisch, B. W.; Dandenault, P. B.; Galkin, I. A.; Hamel, R.; Richards, P. G.

2018-02-01

This paper presents a comparison of modeled and measured electron densities for the 21 August 2017 solar eclipse across the USA. The location of the instrument was (43.81°N, 247.32°E) where the maximum obscuration of 99.6% occurred at 17.53 hr UT on 21 August. The solar apparent time was 9.96 hr, and the duration of the eclipse was 2.7 hr. It was found that if it is assumed that there are no chromosphere emissions at totality, 30% coronal emission remaining at totality gave the best fit to the electron density variation at 150 km. The 30% coronal emission estimate has uncertainties associated with respect to uncertainties in the solar spectrum, the measured electron density, and the amount of chromosphere emissions remaining at totality. The agreement between the modeled and measured electron densities is excellent at 150 km with the assumed 30% coronal emission at totality. At other altitudes, the agreement is very good, but the altitude profile would be improved if the model peak electron density (NmF2) decayed more slowly to better match the data. The minimum NmF2 in the model occurs 10 min after totality when it decreases to 0.55 from its noneclipse value. The minimum of the NmF2 data occurs between 6 and 10 min after totality but is 15% larger. The total electron content decreases to 0.65 of its preeclipse value. These relative changes agree well with those predicted by others prior to the eclipse.

Cross sections for the production of energetic cations by electron impact on N2 and CO2

NASA Technical Reports Server (NTRS)

Iga, I.; Srivastava, S. K.; Rao, M. V. V. S.; Katayama, D. H.

1995-01-01

Dissociative ionization cross sections for the production of singly charged energetic ions by electron impact on N2 and CO2 have been measured. The ions were divided into two groups: one with energies less than 1 eV and the other with energies greater than 1 eV. The ions detected were N+ from N2 and C+, O+, and CO+ from CO2. The electron impact energy range, and cross section data on ions is given.

A comparison of manual and electronic counting for total nucleated cell counts on synovial fluid from canine stifle joints.

PubMed

Atilola, M A; Lumsden, J H; Rooke, F

1986-04-01

Synovial fluids collected from the stifle joints of 20 physically normal adult dogs were subjected to cytological examination. A total nucleated cell count was performed on each sample using both an electronic cell counter and a hemocytometer. The mean of the total counts done with the electronic counter was significantly higher (1008 cells/microL) than that obtained manually with the hemocytometer (848 cells/microL).

Impact of an electronic health record operating room management system in ophthalmology on documentation time, surgical volume, and staffing.

PubMed

Sanders, David S; Read-Brown, Sarah; Tu, Daniel C; Lambert, William E; Choi, Dongseok; Almario, Bella M; Yackel, Thomas R; Brown, Anna S; Chiang, Michael F

2014-05-01

Although electronic health record (EHR) systems have potential benefits, such as improved safety and quality of care, most ophthalmology practices in the United States have not adopted these systems. Concerns persist regarding potential negative impacts on clinical workflow. In particular, the impact of EHR operating room (OR) management systems on clinical efficiency in the ophthalmic surgery setting is unknown. To determine the impact of an EHR OR management system on intraoperative nursing documentation time, surgical volume, and staffing requirements. For documentation time and circulating nurses per procedure, a prospective cohort design was used between January 10, 2012, and January 10, 2013. For surgical volume and overall staffing requirements, a case series design was used between January 29, 2011, and January 28, 2013. This study involved ophthalmic OR nurses (n = 13) and surgeons (n = 25) at an academic medical center. Electronic health record OR management system implementation. (1) Documentation time (percentage of operating time documenting [POTD], absolute documentation time in minutes), (2) surgical volume (procedures/time), and (3) staffing requirements (full-time equivalents, circulating nurses/procedure). Outcomes were measured during a baseline period when paper documentation was used and during the early (first 3 months) and late (4-12 months) periods after EHR implementation. There was a worsening in total POTD in the early EHR period (83%) vs paper baseline (41%) (P < .001). This improved to baseline levels by the late EHR period (46%, P = .28), although POTD in the cataract group remained worse than at baseline (64%, P < .001). There was a worsening in absolute mean documentation time in the early EHR period (16.7 minutes) vs paper baseline (7.5 minutes) (P < .001). This improved in the late EHR period (9.2 minutes) but remained worse than in the paper baseline (P < .001). While cataract procedures required more circulating nurses in the early EHR (mean, 1.9 nurses/procedure) and late EHR (mean, 1.5 nurses/procedure) periods than in the paper baseline (mean, 1.0 nurses/procedure) (P < .001), overall staffing requirements and surgical volume were not significantly different between the periods. Electronic health record OR management system implementation was associated with worsening of intraoperative nursing documentation time especially in shorter procedures. However, it is possible to implement an EHR OR management system without serious negative impacts on surgical volume and staffing requirements.

Impact-generated endolithic habitat within crystalline rocks of the Haughton impact structure, Devon Island, Canada.

PubMed

Pontefract, Alexandra; Osinski, Gordon R; Cockell, Charles S; Moore, Casey A; Moores, John E; Southam, Gordon

2014-06-01

The colonization of rocks by endolithic communities is an advantageous trait, especially in environments such as hot or cold deserts, where large temperature ranges, low water availability, and high-intensity ultraviolet radiation pose a significant challenge to survival and growth. On Mars, similar conditions (albeit more extreme) prevail. In these environments, meteorite impact structures could provide refuge for endolithic organisms. Though initially detrimental to biology, an impact event into a rocky body can favorably change the availability and habitability of a substrate for endolithic organisms, which are then able to (re)colonize microfractures and pore spaces created during the impact. Here, we show how shocked gneisses from the Haughton impact structure, Devon Island, Canada, offer significant refuge for endolithic communities. A total of 28 gneiss samples representing a range of shock states were analyzed, collected from in situ, stable field locations. For each sample, the top centimeter of rock was examined with confocal scanning laser microscopy, scanning electron microscopy, and bright-field microscopy to investigate the relationship of biomass with shock level, which was found to correlate generally with increased shock state and particularly with increased porosity. We found that gneisses, which experienced pressures between 35 and 60 GPa, provide the most ideal habitat for endolithic organisms.

Need for reaction coordinates to ensure a complete basis set in an adiabatic representation of ion-atom collisions

NASA Astrophysics Data System (ADS)

Rabli, Djamal; McCarroll, Ronald

2018-02-01

This review surveys the different theoretical approaches, used to describe inelastic and rearrangement processes in collisions involving atoms and ions. For a range of energies from a few meV up to about 1 keV, the adiabatic representation is expected to be valid and under these conditions, inelastic and rearrangement processes take place via a network of avoided crossings of the potential energy curves of the collision system. In general, such avoided crossings are finite in number. The non-adiabatic coupling, due to the breakdown of the Born-Oppenheimer separation of the electronic and nuclear variables, depends on the ratio of the electron mass to the nuclear mass terms in the total Hamiltonian. By limiting terms in the total Hamiltonian correct to first order in the electron to nuclear mass ratio, a system of reaction coordinates is found which allows for a correct description of both inelastic channels. The connection between the use of reaction coordinates in the quantum description and the electron translation factors of the impact parameter approach is established. A major result is that only when reaction coordinates are used, is it possible to introduce the notion of a minimal basis set. Such a set must include all avoided crossings including both radial coupling and long range Coriolis coupling. But, only when reactive coordinates are used, can such a basis set be considered as complete. In particular when the centre of nuclear mass is used as centre of coordinates, rather than the correct reaction coordinates, it is shown that erroneous results are obtained. A few results to illustrate this important point are presented: one concerning a simple two-state Landau-Zener type avoided crossing, the other concerning a network of multiple crossings in a typical electron capture process involving a highly charged ion with a neutral atom.

The knowledge and attitudes of orthodontic trainees towards orthodontic therapists: a national survey.

PubMed

Patel, Sameer; Mack, Gavin

2017-09-01

To assess the knowledge and attitudes of orthodontic trainees towards orthodontic therapists (OTs) in the UK. Cross-sectional survey. UK-based orthodontic trainees. An electronic survey was sent to all members of the Training Grades Group of the British Orthodontic Society assessing exposure to OTs and their knowledge regarding current supervision guidelines and scope of practice. Attitudes towards OTs were also explored. Seventy-six responses (response rate 57%) were returned. Nearly 90% of trainees had no formal training regarding OTs. A total of 15.5% were aware of the correct current supervision guidelines and there was large variation in the knowledge of OTs' scope of practice. The majority of trainees were happy to supervise OTs, but only 22.4% felt prepared for this during training. In total, 63% of trainees felt that OTs could impact their own future job prospects. Currently, there is minimal formal training provided to trainees regarding the role of OTs. This is reflected in the lack of knowledge regarding supervision guidelines and scope of practice. Overall, trainees felt OTs were positive for the workforce but were concerned regarding the impact of their own future employment.

Absolute Measurements of Field Enhanced Dielectronic Recombination and Electron Impact Excitation

NASA Astrophysics Data System (ADS)

Savin, Daniel Wolf

Absolute measurements have been made of the dielectronic recombination (DR) rate coefficient for C^ {3+}, via the 2s-2p core -excitation, in an external electric field of 11.4 +/- 0.9(1sigma) V cm ^{-1}; and of the electron impact excitation (EIE) rate coefficient for C ^{3+}(2s-2p) at energies near threshold. The ion-rest-frame FWHM of the electron energy spread was 1.74 +/- 0.22(1sigma) eV. The measured DR rate, at a mean electron energy of 8.26 +/- 0.07(1sigma ) eV, was (2.76+/- 0.75)times 10^{-10} cm^{3 } s^{-1}. The uncertainty quoted for the DR rate is the total experimental uncertainty at a 1sigma<=vel. The present DR result appears to agree with an intermediate coupling calculation which uses the isolated-resonance, single-configuration approximation. In comparing with theory, a semi-classical formula was used to determine which recombined ions were field-ionized by the 4.65 kV cm^{-1} fields in the final-charge-state analyzer and not detected. A more precise treatment of field-ionization, which includes the lifetime of the high Rydberg C^{2+} ions in the external field and the time evolution and rotation of the fields experienced by the recombined ions, is needed before a definitive comparison between experiment and theory can be made. For the EIE results, at an ion-rest-frame energy of 10.10 eV, the measured rate coefficient was (7.79+/- 2.10)times 10^{ -8} cm^3 s^ {-1}. The measured cross section was (4.15+/- 1.12)times 10^{ -16} cm^2. The uncertainties quoted here represent the total experimental uncertainty at a 90 percent confidence level. Good agreement is found with other measurements. Agreement is not good with Coulomb -Born with exchange and two-state close-coupling calculations which fall outside the 90-percent-confidence uncertainty limits. Agreement is better with a nine-state close-coupling calculation which lies at the extreme of the uncertainty limits. Taking into account previous measurements in C ^{3+} and also a measurement of EIE in Be^+ which lies 19 percent below close-coupling calculations, there is a suggestion that the C^{3+}(2s-2p) EIE rate coefficient may fall slightly below presently accepted values.

Investigation of mid-latitude electron density enhancement using total electron content measurements and FORMOSAT-3/COSMIC electron density profiles

NASA Astrophysics Data System (ADS)

Rajesh, P. K.; Nanan, Balan; Liu, Jann-Yenq; Lin, Charles C. H.; Chang, S. Y.; Chen, Chia-Hung

This study investigates the mid-latitude electron density enhancement (MEDE) using global ionospheric map (GIM) total electron content (TEC) measurements and FORMOSAT-3/COSMIC (F3/C) electron density profiles. Diurnal, seasonal, latitudinal, and solar activity variations in the occurrence and strength of MEDE are examined using global GIM TEC data in the years 2002 and 2009. The results show that MEDE occurrence is pronounced during 2200-0400 LT, the feature also appears during day. The strength of MEDE maximizes around 0400 LT, and is very weak during daytime. The occurrence and strength show significant longitude dependence, and vary with season and solar activity. Concurrent F3/C electron density profiles also reveal enhancement of the peak electron density and total electron content. Further studies are carried out by examining the role of neutral wind in re-organizing the plasma using SAMI2 and HWM93 models. The results indicate that meridional neutral wind could cause the plasma to converge over mid-latitudes, and thus support in maintaining the enhancement.

Electron-impact ionization of atomic hydrogen at incident electron energies of 15.6, 17.6, 25, and 40 eV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Childers, J. G.; James, K. E.; Hughes, M.

2003-09-01

Absolute doubly differential cross sections for the electron-impact ionization of atomic hydrogen have been measured from near threshold to intermediate energies. The measurements are calibrated to the well-established, accurate differential cross section for electron-impact excitation of the atomic hydrogen transition H(1{sup 2}S{yields}2{sup 2}S+2{sup 2}P). In these experiments background secondary electrons are suppressed by moving the atomic hydrogen target source to and from the collision region. Measurements cover the incident electron energy range of 14.6-40 eV, for scattering angles of 10 degree sign -120 degree sign and are found to be in very good agreement with the results of the mostmore » advanced theoretical models--the convergent close-coupling model and the exterior complex scaling model.« less

Comparative study of resist stabilization techniques for metal etch processing

NASA Astrophysics Data System (ADS)

Becker, Gerry; Ross, Matthew F.; Wong, Selmer S.; Minter, Jason P.; Marlowe, Trey; Livesay, William R.

1999-06-01

This study investigates resist stabilization techniques as they are applied to a metal etch application. The techniques that are compared are conventional deep-UV/thermal stabilization, or UV bake, and electron beam stabilization. The electron beam tool use din this study, an ElectronCure system from AlliedSignal Inc., ELectron Vision Group, utilizes a flood electron source and a non-thermal process. These stabilization techniques are compared with respect to a metal etch process. In this study, two types of resist are considered for stabilization and etch: a g/i-line resist, Shipley SPR-3012, and an advanced i-line, Shipley SPR 955- Cm. For each of these resist the effects of stabilization on resist features are evaluated by post-stabilization SEM analysis. Etch selectivity in all cases is evaluated by using a timed metal etch, and measuring resists remaining relative to total metal thickness etched. Etch selectivity is presented as a function of stabilization condition. Analyses of the effects of the type of stabilization on this method of selectivity measurement are also presented. SEM analysis was also performed on the features after a compete etch process, and is detailed as a function of stabilization condition. Post-etch cleaning is also an important factor impacted by pre-etch resist stabilization. Results of post- etch cleaning are presented for both stabilization methods. SEM inspection is also detailed for the metal features after resist removal processing.

Mapping the impact of patient and public involvement on health and social care research: a systematic review.

PubMed

Brett, Jo; Staniszewska, Sophie; Mockford, Carole; Herron-Marx, Sandra; Hughes, John; Tysall, Colin; Suleman, Rashida

2014-10-01

There is an increasing international interest in patient and public involvement (PPI) in research, yet relatively little robust evidence exists about its impact on health and social care research. To identify the impact of patient and public involvement on health and social care research. A systematic search of electronic databases and health libraries was undertaken from 1995 to 2009. Data were extracted and quality assessed utilizing the guidelines of the NHS Centre for Reviews and Dissemination 2009 and the Critical Appraisal Skills Programme (CASP). Grey literature was assessed using the Dixon-Woods et al. (2005) checklist. All study types that reported the impact PPI had on the health and/or social care research study. A total of 66 studies reporting the impact of PPI on health and social care research were included. The positive impacts identified enhanced the quality and appropriateness of research. Impacts were reported for all stages of research, including the development of user-focused research objectives, development of user-relevant research questions, development of user-friendly information, questionnaires and interview schedules, more appropriate recruitment strategies for studies, consumer-focused interpretation of data and enhanced implementation and dissemination of study results. Some challenging impacts were also identified. This study provides the first international evidence of PPI impact that has emerged at all key stages of the research process. However, much of the evidence base concerning impact remains weak and needs significant enhancement in the next decade. © 2012 John Wiley & Sons Ltd.

Cost, staffing and quality impact of bedside electronic medical record (EMR) in nursing homes.

PubMed

Rantz, Marilyn J; Hicks, Lanis; Petroski, Gregory F; Madsen, Richard W; Alexander, Greg; Galambos, Colleen; Conn, Vicki; Scott-Cawiezell, Jill; Zwygart-Stauffacher, Mary; Greenwald, Leslie

2010-09-01

There is growing political pressure for nursing homes to implement the electronic medical record (EMR) but there is little evidence of its impact on resident care. The purpose of this study was to test the unique and combined contributions of EMR at the bedside and on-site clinical consultation by gerontological expert nurses on cost, staffing, and quality of care in nursing homes. Eighteen nursing facilities in 3 states participated in a 4-group 24-month comparison: Group 1 implemented bedside EMR, used nurse consultation; Group 2 implemented bedside EMR only; Group 3 used nurse consultation only; Group 4 neither. Intervention sites (Groups 1 and 2) received substantial, partial financial support from CMS to implement EMR. Costs and staffing were measured from Medicaid cost reports, and staff retention from primary data collection; resident outcomes were measured by MDS-based quality indicators and quality measures. Total costs increased in both intervention groups that implemented technology; staffing and staff retention remained constant. Improvement trends were detected in resident outcomes of ADLs, range of motion, and high-risk pressure sores for both intervention groups but not in comparison groups. Implementation of bedside EMR is not cost neutral. There were increased total costs for all intervention facilities. These costs were not a result of increased direct care staffing or increased staff turnover. Nursing home leaders and policy makers need to be aware of on-going hardware and software costs as well as costs of continual technical support for the EMR and constant staff orientation to use the system. EMR can contribute to the quality of nursing home care and can be enhanced by on-site consultation by nurses with graduate education in nursing and expertise in gerontology. Copyright 2010 American Medical Directors Association. Published by Elsevier Inc. All rights reserved.

Use of statistical tools to evaluate the reductive dechlorination of high levels of TCE in microcosm studies.

PubMed

Harkness, Mark; Fisher, Angela; Lee, Michael D; Mack, E Erin; Payne, Jo Ann; Dworatzek, Sandra; Roberts, Jeff; Acheson, Carolyn; Herrmann, Ronald; Possolo, Antonio

2012-04-01

A large, multi-laboratory microcosm study was performed to select amendments for supporting reductive dechlorination of high levels of trichloroethylene (TCE) found at an industrial site in the United Kingdom (UK) containing dense non-aqueous phase liquid (DNAPL) TCE. The study was designed as a fractional factorial experiment involving 177 bottles distributed between four industrial laboratories and was used to assess the impact of six electron donors, bioaugmentation, addition of supplemental nutrients, and two TCE levels (0.57 and 1.90 mM or 75 and 250 mg/L in the aqueous phase) on TCE dechlorination. Performance was assessed based on the concentration changes of TCE and reductive dechlorination degradation products. The chemical data was evaluated using analysis of variance (ANOVA) and survival analysis techniques to determine both main effects and important interactions for all the experimental variables during the 203-day study. The statistically based design and analysis provided powerful tools that aided decision-making for field application of this technology. The analysis showed that emulsified vegetable oil (EVO), lactate, and methanol were the most effective electron donors, promoting rapid and complete dechlorination of TCE to ethene. Bioaugmentation and nutrient addition also had a statistically significant positive impact on TCE dechlorination. In addition, the microbial community was measured using phospholipid fatty acid analysis (PLFA) for quantification of total biomass and characterization of the community structure and quantitative polymerase chain reaction (qPCR) for enumeration of Dehalococcoides organisms (Dhc) and the vinyl chloride reductase (vcrA) gene. The highest increase in levels of total biomass and Dhc was observed in the EVO microcosms, which correlated well with the dechlorination results. Copyright © 2012 Elsevier B.V. All rights reserved.

Electron-impact excitation of diatomic hydride cations II: OH+ and SH+

NASA Astrophysics Data System (ADS)

Hamilton, James R.; Faure, Alexandre; Tennyson, Jonathan

2018-05-01

R-matrix calculations combined with the adiabatic-nuclei-rotation and Coulomb-Born approximations are used to compute electron-impact rotational rate coefficients for two open-shell diatomic cations of astrophysical interest: the hydoxyl and sulphanyl ions, OH+ and SH+. Hyperfine resolved rate coefficients are deduced using the infinite-order-sudden approximation. The propensity rule ΔF = Δj = ΔN = ±1 is observed, as is expected for cations with a large dipole moment. A model for OH+ excitation in the Orion Bar photon-dominated region is presented which nicely reproduces Herschel observations for an electron fraction xe = 10-4 and an OH+ column density of 3 × 1013 cm-2. Electron-impact electronic excitation cross-sections and rate coefficients for the ions are also presented.

Differential Cross Sections for Ionization of Argon by 1 keV Positron and Electron Impact

NASA Astrophysics Data System (ADS)

Gavin, J.; DuBois, R. D.; de Lucio, O. G.

2014-04-01

Differential information was generated by establishing coincidences and imposing conditions on data recorded for target ions, scattered projectiles, and ejected electrons, as a function of projectile energy loss and scattering angles; in order to describe the interaction between a positron (electron) 1 keV beam and a simple Ar jet. Single ionization triply differential cross section (TDCS) results exhibit two distinct regions (lobes) for which binary (events arising from 2-body interaction) and recoil (events which can only be produced by many-body interactions) interactions are associated. Results indicate that binary events are significantly larger for positron impact, in accordance with theoretical predictions. A similar feature is found for different energy losses and scattering angles. Intensity of the recoil lobe for both projectiles, positron and electron, is observed to depend on the energy loss and scattering angle. Also, it can be noticed that for positron impact the recoil interactions intensity is larger than that observed for electron impact.

Differential cross sections for electron impact excitation of the Herzberg pseudocontinuum of molecular oxygen

NASA Astrophysics Data System (ADS)

Green, M. A.; Maddern, T.; Brunger, M. J.; Campbell, L.; Cartwright, D. C.; Newell, W. R.; Teubner, P. J. O.

2002-09-01

We report differential cross sections (DCSs) for electron impact excitation of the sum (c1Σ u- + A'3 Δ u + A3 Σ u+) of the three states that constitute the Herzberg pseudocontinuum in O2. These DCSs were measured at seven incident electron energies in the range 9-20 eV and over the scattered electron angular range 10-90°. We note that this represents a far more detailed study than has hitherto previously been reported. In their review on electron-diatomic molecule scattering systems, Brunger and Buckman (Brunger M J and Buckman S J 2002 Phys. Rep. 357 215) clearly identified gaps in our knowledge for electron impact excitation of the Herzberg electronic states. The present study rectifies this situation and, additionally, seeks to stimulate theoreticians to extend their existing integral cross section calculations, for the c1 Σ u-, A'3 Δ u and A3 Σ u+ states, to the DCS-level.

Understanding the Role of Electron-driven Processes in Atmospheric Behaviour

NASA Astrophysics Data System (ADS)

Brunger, M. J.; Campbell, L.; Jones, D. B.; Cartwright, D. C.

2004-12-01

Electron-impact excitation plays a major role in emission from aurora and a less significant but nonetheless crucial role in the dayglow and nightglow. For some molecules, such as N2, O2 and NO, electron-impact excitation can be followed by radiative cascade through many different sets of energy levels, producing emission with a large number of lines. We review the application of our statistical equilibrium program to predict this rich spectrum of radiation, and we compare results we have obtained against available independent measurements. In addition, we also review the calculation of energy transfer rates from electrons to N2, O2 and NO in the thermosphere. Energy transfer from electrons to neutral gases and ions is one of the dominant electron cooling processes in the ionosphere, and the role of vibrationally excited N2 and O2 in this is particularly significant. The importance of the energy dependence and magnitude of the electron-impact vibrational cross sections in the calculation of these rates is assessed.

Experimental and theoretical triple differential cross sections for electron-impact ionization of Ar (3p) for equal energy final state electrons

NASA Astrophysics Data System (ADS)

Amami, Sadek; Ozer, Zehra N.; Dogan, Mevlut; Yavuz, Murat; Varol, Onur; Madison, Don

2016-09-01

There have been several studies of electron-impact ionization of inert gases for asymmetric final state energy sharing and normally one electron has an energy significantly higher than the other. However, there have been relatively few studies examining equal energy final state electrons. Here we report experimental and theoretical triple differential cross sections for electron impact ionization of Ar (3p) for equal energy sharing of the outgoing electrons. Previous experimental results combined with some new measurements are compared with distorted wave born approximation (DWBA) results, DWBA results using the Ward-Macek (WM) approximation for the post collision interaction (PCI), and three-body distorted wave (3DW) which includes PCI without approximation. The results show that it is crucially important to include PCI in the calculation particularly for lower energies and that the WM approximation is valid only for high energies. The 3DW, on the other hand, is in reasonably good agreement with data down to fairly low energies.

The Use of Electronic Book Theft Detection Systems in Libraries.

ERIC Educational Resources Information Center

Witt, Thomas B.

1996-01-01

Although electronic book theft detection systems can be a deterrent to library material theft, no electronic system is foolproof, and a total security program is necessary to ensure collection security. Describes how book theft detection systems work, their effectiveness, and the problems inherent in technology. A total security program considers…

Total Dose Survivability of Hubble Electronic Components

NASA Technical Reports Server (NTRS)

Xapsos, M. A.; Stauffer, C.; Jordan, T.; Poivey, C.; Haskins, D. N.; Lum, G.; Pergosky, A. M.; Smith, D. C.; LaBel, K. A.

2017-01-01

A total dose analysis for exposure of electronic parts at the box level is presented for the Hubble Space Telescope. This was done using solid angle sectoring/3-dimensional ray trace and Monte Carlo radiation transport simulations. Results are discussed in terms of parts that are potential total dose concerns.

Triple differential cross sections for the electron-impact ionization of H{sub 2} molecules for equal and unequal outgoing electron energies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colgan, J.; Al-Hagan, O.; Madison, D. H.

A comprehensive theoretical and experimental investigation of the triple differential cross sections arising from the electron-impact ionization of molecular hydrogen is made, at an incident electron energy of 35.4 eV, for cases where the outgoing electrons have equal and unequal energies, and for a range of experimental geometries. Generally, good agreement is found between two theoretical approaches and experiment, with the best agreement arising for intermediate geometries with large gun angles and for the perpendicular geometry.

Calculation of ground state rotational populations for kinetic gas homonuclear diatomic molecules including electron-impact excitation and wall collisions.

PubMed

Farley, David R

2010-09-07

A model has been developed to calculate the ground state rotational populations of homonuclear diatomic molecules in kinetic gases, including the effects of electron-impact excitation, wall collisions, and gas feed rate. The equations are exact within the accuracy of the cross sections used and of the assumed equilibrating effect of wall collisions. It is found that the inflow of feed gas and equilibrating wall collisions can significantly affect the rotational distribution in competition with nonequilibrating electron-impact effects. The resulting steady-state rotational distributions are generally Boltzmann for N≥3, with a rotational temperature between the wall and feed gas temperatures. The N=0,1,2 rotational level populations depend sensitively on the relative rates of electron-impact excitation versus wall collision and gas feed rates.

Perceptions of Undergraduate Students and Faculty Regarding the Impact of Electronic Communication on the Written-Communication Skills of Undergraduate Students

ERIC Educational Resources Information Center

Houser, Laura Ann Camlet

2012-01-01

This narrative-qualitative study investigated the perceived impact that electronic communication has on the written-communication skills of undergraduate students. Open-ended survey questions queried the experiences of undergraduate students who use electronic communication, as well as the perceptions of faculty who teach undergraduate students.…

The Impact of Electronic Health Records on Healthcare Professional's Beliefs and Attitudes toward Face to Face Communication

ERIC Educational Resources Information Center

Nickles, Kenneth Patrick

2012-01-01

The impact of electronic health records on healthcare professional's beliefs and attitudes toward face to face communication during patient and provider interactions was examined. Quantitative survey research assessed user attitudes towards an electronic health record system and revealed that healthcare professionals from a wide range of…

Is There Evidence of Cost Benefits of Electronic Medical Records, Standards, or Interoperability in Hospital Information Systems? Overview of Systematic Reviews

PubMed Central

2017-01-01

Background Electronic health (eHealth) interventions may improve the quality of care by providing timely, accessible information about one patient or an entire population. Electronic patient care information forms the nucleus of computerized health information systems. However, interoperability among systems depends on the adoption of information standards. Additionally, investing in technology systems requires cost-effectiveness studies to ensure the sustainability of processes for stakeholders. Objective The objective of this study was to assess cost-effectiveness of the use of electronically available inpatient data systems, health information exchange, or standards to support interoperability among systems. Methods An overview of systematic reviews was conducted, assessing the MEDLINE, Cochrane Library, LILACS, and IEEE Library databases to identify relevant studies published through February 2016. The search was supplemented by citations from the selected papers. The primary outcome sought the cost-effectiveness, and the secondary outcome was the impact on quality of care. Independent reviewers selected studies, and disagreement was resolved by consensus. The quality of the included studies was evaluated using a measurement tool to assess systematic reviews (AMSTAR). Results The primary search identified 286 papers, and two papers were manually included. A total of 211 were systematic reviews. From the 20 studies that were selected after screening the title and abstract, 14 were deemed ineligible, and six met the inclusion criteria. The interventions did not show a measurable effect on cost-effectiveness. Despite the limited number of studies, the heterogeneity of electronic systems reported, and the types of intervention in hospital routines, it was possible to identify some preliminary benefits in quality of care. Hospital information systems, along with information sharing, had the potential to improve clinical practice by reducing staff errors or incidents, improving automated harm detection, monitoring infections more effectively, and enhancing the continuity of care during physician handoffs. Conclusions This review identified some benefits in the quality of care but did not provide evidence that the implementation of eHealth interventions had a measurable impact on cost-effectiveness in hospital settings. However, further evidence is needed to infer the impact of standards adoption or interoperability in cost benefits of health care; this in turn requires further research. PMID:28851681

Is There Evidence of Cost Benefits of Electronic Medical Records, Standards, or Interoperability in Hospital Information Systems? Overview of Systematic Reviews.

PubMed

Reis, Zilma Silveira Nogueira; Maia, Thais Abreu; Marcolino, Milena Soriano; Becerra-Posada, Francisco; Novillo-Ortiz, David; Ribeiro, Antonio Luiz Pinho

2017-08-29

Electronic health (eHealth) interventions may improve the quality of care by providing timely, accessible information about one patient or an entire population. Electronic patient care information forms the nucleus of computerized health information systems. However, interoperability among systems depends on the adoption of information standards. Additionally, investing in technology systems requires cost-effectiveness studies to ensure the sustainability of processes for stakeholders. The objective of this study was to assess cost-effectiveness of the use of electronically available inpatient data systems, health information exchange, or standards to support interoperability among systems. An overview of systematic reviews was conducted, assessing the MEDLINE, Cochrane Library, LILACS, and IEEE Library databases to identify relevant studies published through February 2016. The search was supplemented by citations from the selected papers. The primary outcome sought the cost-effectiveness, and the secondary outcome was the impact on quality of care. Independent reviewers selected studies, and disagreement was resolved by consensus. The quality of the included studies was evaluated using a measurement tool to assess systematic reviews (AMSTAR). The primary search identified 286 papers, and two papers were manually included. A total of 211 were systematic reviews. From the 20 studies that were selected after screening the title and abstract, 14 were deemed ineligible, and six met the inclusion criteria. The interventions did not show a measurable effect on cost-effectiveness. Despite the limited number of studies, the heterogeneity of electronic systems reported, and the types of intervention in hospital routines, it was possible to identify some preliminary benefits in quality of care. Hospital information systems, along with information sharing, had the potential to improve clinical practice by reducing staff errors or incidents, improving automated harm detection, monitoring infections more effectively, and enhancing the continuity of care during physician handoffs. This review identified some benefits in the quality of care but did not provide evidence that the implementation of eHealth interventions had a measurable impact on cost-effectiveness in hospital settings. However, further evidence is needed to infer the impact of standards adoption or interoperability in cost benefits of health care; this in turn requires further research. ©Zilma Silveira Nogueira Reis, Thais Abreu Maia, Milena Soriano Marcolino, Francisco Becerra-Posada, David Novillo-Ortiz, Antonio Luiz Pinho Ribeiro. Originally published in JMIR Medical Informatics (http://medinform.jmir.org), 29.08.2017.

Substrate influence on the interlayer electron-phonon couplings in fullerene films probed with doubly-resonant SFG spectroscopy.

PubMed

Elsenbeck, Dennis; Das, Sushanta K; Velarde, Luis

2017-07-19

We present doubly-resonant sum frequency generation (DR-SFG) spectra of fullerene thin films on metallic and dielectric substrates as a way to investigate the interplay between nuclear and electronic coupling at buried interfaces. Modal and substrate selectivity in the electronic enhancement of the C 60 vibrational signatures is demonstrated for excitation wavelengths spanning the visible range. While the SFG response of the totally symmetric A g (2) mode of fullerene is distinctly coupled to the optically allowed electronic transition corresponding to the HOMO-LUMO+1 of C 60 (ca. 2.6 eV), the T 1u (4) vibrational mode appears to be coupled to a symmetry-forbidden HOMO-LUMO transition at lower energies (ca. 2.0 eV). For dielectric substrates, the DR-SFG intensity of the T 1u (4) mode shows lack of enhancement for upconversion wavelengths off-resonance with the optically-dark LUMO. However, the T 1u (4) mode shows a unique coupling to an intermediate state (∼2.4 eV) only for the fullerene films on the gold substrate. We attribute this coupling to unique interactions at the buried C 60 /gold interface. These results demonstrate the occurrence of clear electron-phonon couplings at the C 60 /substrate interfaces and shed light on the impact of these couplings on the optical response of electronically excited fullerene. This coupling may influence charge and energy transport in organic electronic devices mediated by vibrational motions. We also demonstrate a potential use of this added selectivity in chemical imaging.

Low-energy Electrons in Gamma-Ray Burst Afterglow Models

NASA Astrophysics Data System (ADS)

Jóhannesson, Guđlaugur; Björnsson, Gunnlaugur

2018-05-01

Observations of gamma-ray burst (GRB) afterglows have long provided the most detailed information about the origin of this spectacular phenomenon. The model that is most commonly used to extract physical properties of the event from the observations is the relativistic fireball model, where ejected material moving at relativistic speeds creates a shock wave when it interacts with the surrounding medium. Electrons are accelerated in the shock wave, generating the observed synchrotron emission through interactions with the magnetic field in the downstream medium. It is usually assumed that the accelerated electrons follow a simple power-law distribution in energy between specific energy boundaries, and that no electron exists outside these boundaries. This Letter explores the consequences of adding a low-energy power-law segment to the electron distribution with energy that contributes insignificantly to the total energy budget of the distribution. The low-energy electrons have a significant impact on the radio emission, providing synchrotron absorption and emission at these long wavelengths. Shorter wavelengths are affected through the normalization of the distribution. The new model is used to analyze the light curves of GRB 990510, and the resulting parameters are compared to a model without the extra electrons. The quality of the fit and the best-fit parameters are significantly affected by the additional model component. The new component is in one case found to strongly affect the X-ray light curves, showing how changes to the model at radio frequencies can affect light curves at other frequencies through changes in best-fit model parameters.

Carbon Footprint in Flexible Ureteroscopy: A Comparative Study on the Environmental Impact of Reusable and Single-Use Ureteroscopes.

PubMed

Davis, Niall F; McGrath, Shannon; Quinlan, Mark; Jack, Gregory; Lawrentschuk, Nathan; Bolton, Damien M

2018-03-01

There are no comparative assessments on the environmental impact of endourologic instruments. We evaluated and compared the environmental impact of single-use flexible ureteroscopes with reusable flexible ureteroscopes. An analysis of the typical life cycle of the LithoVue™ (Boston Scientific) single-use digital flexible ureteroscope and Olympus Flexible Video Ureteroscope (URV-F) was performed. To measure the carbon footprint, data were obtained on manufacturing of single-use and reusable flexible ureteroscopes and from typical uses obtained with a reusable scope, including repairs, replacement instruments, and ultimate disposal of both ureteroscopes. The solid waste generated (kg) and energy consumed (kWh) during each case were quantified and converted into their equivalent mass of carbon dioxide (kg of CO 2 ) released. Flexible ureteroscopic raw materials composed of plastic (90%), steel (4%), electronics (4%), and rubber (2%). The manufacturing cost of a flexible ureteroscope was 11.49 kg of CO 2 per 1 kg of ureteroscope. The weight of the single-use LithoVue and URV-F flexible ureteroscope was 0.3 and 1 kg, respectively. The total carbon footprint of the lifecycle assessment of the LithoVue was 4.43 kg of CO 2 per endourologic case. The total carbon footprint of the lifecycle of the reusable ureteroscope was 4.47 kg of CO 2 per case. The environmental impacts of the reusable flexible ureteroscope and the single-use flexible ureteroscope are comparable. Urologists should be aware that the typical life cycle of urologic instruments is a concerning source of environmental emissions.

Mixing of t2 g-eg orbitals in 4 d and 5 d transition metal oxides

NASA Astrophysics Data System (ADS)

Stamokostas, Georgios L.; Fiete, Gregory A.

2018-02-01

Using exact diagonalization, we study the spin-orbit coupling and interaction-induced mixing between t2 g and egd -orbital states in a cubic crystalline environment, as commonly occurs in transition metal oxides. We make a direct comparison with the widely used t2 g-only or eg-only models, depending on electronic filling. We consider all electron fillings of the d shell and compute the total magnetic moment, the spin, the occupancy of each orbital, and the effective spin-orbit coupling strength (renormalized through interaction effects) in terms of the bare interaction parameters, spin-orbit coupling, and crystal-field splitting, focusing on the parameter ranges relevant to 4 d and 5 d transition metal oxides. In various limits, we provide perturbative results consistent with our numerical calculations. We find that the t2 g-eg mixing can be large, with up to 20% occupation of orbitals that are nominally "empty," which has experimental implications for the interpretation of the branching ratio in experiments, and can impact the effective local moment Hamiltonian used to study magnetic phases and magnetic excitations in transition metal oxides. Our results can aid the theoretical interpretation of experiments on these materials, which often fall in a regime of intermediate coupling with respect to electron-electron interactions.

A study of the Ionospheric electron density profile with FORMOSAT-3/COSMIC observation data

NASA Astrophysics Data System (ADS)

Chou, Min-Yang; Tsai, Ho-Fang; Lin, Chi-Yen; Lee, I.-Te; Lin, Charles; Liu, Jann-Yenq

2015-04-01

The GPS Occultation Experiment payload onboard FORMOSAT-3/COSMIC microsatellite constellation is capable of scanning the ionospheric structure by the radio occultation (RO) technique to retrieve precise electron density profiles since 2006. Due to the success of FORMOSAT-3/COSMIC, the follow-on mission, FORMOSAT-7/COSMIC-2, is to launch 12 microsatellites in 2016 and 2018, respectively, with　the Global Navigation Satellite Systems (GNSS) RO instrument onboard for tracking GPS, Galileo and/or GLONASS satellite signals and to provide more than 8,000 RO soundings per day globally. An overview of the validation of the FORMOSAT-3/COSMIC ionospheric profiling is given by means of the traditional Abel transform through bending angle and total electron content (TEC), while the ionospheric data assimilation is also applied, based on the Gauss-Markov Kalman filter with the International Reference Ionosphere model (IRI-2007) and global ionosphere map (GIM) as background model, to assimilate TEC observations from FORMOSAT-3/COSMIC. The results shows comparison of electron density profiles from Abel inversion and data assimilation. Furthermore, an observing system simulation experiment is also applied to determine the impact of FORMOSAT-7/COSMIC-2 on ionospheric weather monitoring, which reveals an opportunity on advanced study of small spatial and temporal variations in the ionosphere.

Observation of two-center interference effects for electron impact ionization of N2

NASA Astrophysics Data System (ADS)

Chaluvadi, Hari; Nur Ozer, Zehra; Dogan, Mevlut; Ning, Chuangang; Colgan, James; Madison, Don

2015-08-01

In 1966, Cohen and Fano (1966 Phys. Rev. 150 30) suggested that one should be able to observe the equivalent of Young’s double slit interference if the double slits were replaced by a diatomic molecule. This suggestion inspired many experimental and theoretical studies searching for double slit interference effects both for photon and particle ionization of diatomic molecules. These effects turned out to be so small for particle ionization that this work proceeded slowly and evidence for interference effects were only found by looking at cross section ratios. Most of the early particle work concentrated on double differential cross sections for heavy particle scattering and the first evidence for two-center interference for electron-impact triple differential cross section (TDCS) did not appear until 2006 for ionization of H2. Subsequent work has now firmly established that two-center interference effects can be seen in the TDCS for electron-impact ionization of H2. However, in spite of several experimental and theoretical studies, similar effects have not been found for electron-impact ionization of N2. Here we report the first evidence for two-center interference for electron-impact ionization of N2.

Absolute cross-section measurements of inner-shell ionization

NASA Astrophysics Data System (ADS)

Schneider, Hans; Tobehn, Ingo; Ebel, Frank; Hippler, Rainer

1994-12-01

Cross section ratios for K- and L-shell ionization of thin silver and gold targets by positron and electron impact have been determined at projectile energies of 30 70 keV. The experimental results are confirmed by calculations in plane wave Born approximation (PWBA) which include an electron exchange term and account for the deceleration or acceleration of the incident projectile in the nuclear field of the target atom. We report first absolute cross sections for K- and L-shell ionization of silver and gold targets by lepton impact in the threshold region. We have measured the corresponding cross sections for electron (e-) impact with an electron gun and the same experimental set-up.

Electron-impact dissociation of molecular hydrogen into neutral fragments

NASA Astrophysics Data System (ADS)

Scarlett, Liam H.; Tapley, Jonathan K.; Fursa, Dmitry V.; Zammit, Mark C.; Savage, Jeremy S.; Bray, Igor

2018-02-01

We present convergent close-coupling calculations of electron-impact dissociation of the ground state of molecular hydrogen into neutral fragments over the range of impact energies from 6 to 300 eV. The calculations account for dissociative excitation, excitation radiative decay dissociation, and predissociation through all bound electronic triplet states, and singlet states up to the D' 1 Π u state. An estimate is given for the contribution from the remaining bound electronic singlet states. Our results are in agreement with the recommended data of Yoon et al. [J. Phys. Chem. Ref. Data 37, 913 (2008)] in the low (6-12 eV) and high (60-70 eV) energy regions, but somewhat lower at the intermediate energies.

Retrospective database study to assess the economic impact of hip fracture in the United Kingdom.

PubMed

Lambrelli, Dimitra; Burge, Russel; Raluy-Callado, Mireia; Chen, Shih-Yin; Wu, Ning; Schoenfeld, Michael J

2014-11-01

Publications containing recent, real-world data on the economic impact of hip fractures in the UK are lacking. This retrospective electronic medical records database analysis assessed medication and healthcare resource use, direct healthcare costs, and factors predicting increased resource use and costs in adult UK hip fracture patients. Data were obtained from the Clinical Practice Research Datalink linked to the Hospital Episode Statistics for adult patients hospitalized for their first hip fracture between January 1, 2006 and March 31, 2011 (index event); healthcare costs were calculated from the National Health Service perspective using 2011-2012 cost data. Data from 8028 patients were analyzed. Resource use and costs were statistically significantly higher in the year following fracture (mean total [standard deviation (SD)] cost £7359 [£14,937]) compared with the year before fracture (mean total [SD] cost £3122 [£9435]; p < 0.001), and were similar to the total amount of the index hospitalization (mean total [SD] cost £8330 [£2627]). Multivariate regression analysis (using an estimated generalized linear model) showed that older age, male gender, higher comorbidity, osteoporosis, discharge to another institution compared with home, and pre-index hospitalization and outpatient visits were associated with increased post-index hospitalization healthcare costs (all p < 0.05). Although we did not capture all pre- and post-index costs and healthcare utilization, this study provides important insights regarding the characteristics of patients with hip fracture, and information that will be useful in burden-of-illness and economic analyses.

A Budget Impact Analysis of Newly Available Hepatitis C Therapeutics and the Financial Burden on a State Correctional System.

PubMed

Nguyen, John T; Rich, Josiah D; Brockmann, Bradley W; Vohr, Fred; Spaulding, Anne; Montague, Brian T

2015-08-01

Hepatitis C virus (HCV) infection continues to disproportionately affect incarcerated populations. New HCV drugs present opportunities and challenges to address HCV in corrections. The goal of this study was to evaluate the impact of the treatment costs for HCV infection in a state correctional population through a budget impact analysis comparing differing treatment strategies. Electronic and paper medical records were reviewed to estimate the prevalence of hepatitis C within the Rhode Island Department of Corrections. Three treatment strategies were evaluated as follows: (1) treating all chronically infected persons, (2) treating only patients with demonstrated fibrosis, and (3) treating only patients with advanced fibrosis. Budget impact was computed as the percentage of pharmacy and overall healthcare expenditures accrued by total drug costs assuming entirely interferon-free therapy. Sensitivity analyses assessed potential variance in costs related to variability in HCV prevalence, genotype, estimated variation in market pricing, length of stay for the sentenced population, and uptake of newly available regimens. Chronic HCV prevalence was estimated at 17% of the total population. Treating all sentenced inmates with at least 6 months remaining of their sentence would cost about $34 million-13 times the pharmacy budget and almost twice the overall healthcare budget. Treating inmates with advanced fibrosis would cost about $15 million. A hypothetical 50% reduction in total drug costs for future therapies could cost $17 million to treat all eligible inmates. With immense costs projected with new treatment, it is unlikely that correctional facilities will have the capacity to treat all those afflicted with HCV. Alternative payment strategies in collaboration with outside programs may be necessary to curb this epidemic. In order to improve care and treatment delivery, drug costs also need to be seriously reevaluated to be more accessible and equitable now that HCV is more curable.

Electron-impact ionization and electron attachment cross sections of radicals important in transient gaseous discharges

NASA Technical Reports Server (NTRS)

Lee, Long C.; Srivastava, Santosh K.

1990-01-01

Electron-impact ionization and electron attachment cross sections of radicals and excited molecules were measured using an apparatus that consists of an electron beam, a molecular beam and a laser beam. The information obtained is needed for the pulse power applications in the areas of high power gaseous discharge switches, high energy lasers, particle beam experiments, and electromagnetic pulse systems. The basic data needed for the development of optically-controlled discharge switches were also investigated. Transient current pulses induced by laser irradiation of discharge media were observed and applied for the study of electron-molecule reaction kinetics in gaseous discharges.

Excited level populations and excitation kinetics of nonequilibrium ionizing argon discharge plasma of atmospheric pressure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akatsuka, Hiroshi

2009-04-15

Population densities of excited states of argon atoms are theoretically examined for ionizing argon plasma in a state of nonequilibrium under atmospheric pressure from the viewpoint of elementary processes with collisional radiative model. The dependence of excited state populations on the electron and gas temperatures is discussed. Two electron density regimes are found, which are distinguished by the population and depopulation mechanisms for the excited states in problem. When the electron impact excitation frequency for the population or depopulation is lower than the atomic impact one, the electron density of the plasma is considered as low to estimate the populationmore » and depopulation processes. Some remarkable characteristics of population and depopulation mechanisms are found for the low electron density atmospheric plasma, where thermal relaxation by atomic collisions becomes the predominant process within the group of close-energy states in the ionizing plasma of atmospheric pressure, and the excitation temperature is almost the same as the gas temperature. In addition to the collisional relaxation by argon atoms, electron impact excitation from the ground state is also an essential population mechanism. The ratios of population density of the levels pairs, between which exists a large energy gap, include information on the electron collisional kinetics. For high electron density, the effect of atomic collisional relaxation becomes weak. For this case, the excitation mechanism is explained as electron impact ladderlike excitation similar to low-pressure ionizing plasma, since the electron collision becomes the dominant process for the population and depopulation kinetics.« less

Health consequences of exposure to brominated flame retardants: a systematic review.

PubMed

Kim, Young Ran; Harden, Fiona A; Toms, Leisa-Maree L; Norman, Rosana E

2014-07-01

Brominated flame retardants (BFRs), are chemicals widely used in consumer products including electronics, vehicles, plastics and textiles to reduce flammability. Experimental animal studies have confirmed that these compounds may interfere with thyroid hormone homeostasis and neurodevelopment but to date health effects in humans have not been systematically examined. To conduct a systematic review of studies on the health impacts of exposure to BFRs in humans, with a particular focus on children. A systematic review was conducted using the MEDLINE and EMBASE electronic databases up to 1 February 2012. Published cohort, cross-sectional, and case-control studies exploring the relationship between BFR exposure and various health outcomes were included. In total, 36 epidemiological studies meeting the pre-determined inclusion criteria were included. Plausible outcomes associated with BFR exposure include diabetes, neurobehavioral and developmental disorders, cancer, reproductive health effects and alteration in thyroid function. Evidence for a causal relationship between exposure to BFRs and health outcomes was evaluated within the Bradford Hill framework. Although there is suggestive evidence that exposure to BFRs is harmful to health, further epidemiological investigations particularly among children, and long-term monitoring and surveillance of chemical impacts on humans are required to confirm these relationships. Copyright © 2014 Elsevier Ltd. All rights reserved.

The kinetic energy spectrum of protons produced by the dissociative ionization of H2 by electron impact

NASA Technical Reports Server (NTRS)

Khakoo, M. A.; Srivastava, S. K.

1985-01-01

The kinetic energy spectra of protons resulting from the dissociative ionization of H2 by electron impact have been measured for electron impact energies from threshold (approximately 17 eV) to 160 eV at 90 deg and 30 deg detection angles, using a crossed-beam experimental arrangement. To check reliability, two separate proton energy analysis methods have been employed, i.e., a time-of-flight proton energy analysis and an electrostatic hemispherical energy analyzer. The present results are compared with previous measurements.

Compendium of Total Ionizing Dose and Displacement Damage for Candidate Spacecraft Electronics for NASA

NASA Technical Reports Server (NTRS)

Cochran, Donna J.; Boutte, Alvin J.; Chen, Dakai; Pellish, Jonathan A.; Ladbury, Raymond L.; Casey, Megan C.; Campola, Michael J.; Wilcox, Edward P.; Obryan, Martha V.; LaBel, Kenneth A.;

Electronic structure and partial charge distribution of doxorubicin under different molecular environments

NASA Astrophysics Data System (ADS)

Poudel, Lokendra

Doxorubicin (trade name Adriamycin, abbreviated DOX) is a well-known an- thracyclic chemotherapeutic used in treating a variety of cancers including acute leukemia, lymphoma, multiple myeloma, and a range of stomach, lung, bladder, bone, breast, and ovarian cancers. The purpose of the present work is to study electronic structure, partial charge distribution and interaction energy of DOX under different environments. It provides a framework for better understanding of bioactivity of DOX with DNA. While in this work, we focus on DOX -- DNA interactions; the obtained knowledge could be translated to other drug -- target interactions or biomolecular interactions. The electronic structure and partial charge distribution of DOX in three dierent molecular environments: isolated, solvated, and intercalated into a DNA complex,were studied by rst principles density functional methods. It is shown that the addition of solvating water molecules to DOX and the proximity and interaction with DNA has a signicant impact on the electronic structure as well as the partial charge distribution. The calculated total partial charges for DOX in the three models are 0.0, +0.123 and -0.06 electrons for the isolated, solvated, and intercalated state, respectively. Furthermore, by using the more accurate ab initio partial charge values on every atom in the models, signicant improvement in estimating the DOX-DNA interaction energy is obtained in conjunction with the NAnoscale Molecular Dynamics (NAMD) code. The electronic structure of the DOX-DNA is further elucidated by resolving the total density of states (TDOS) into dierent functional groups of DOX, DNA, water, co-crystallized Spermine molecule, and Na ions. The surface partial charge distribution in the DOX-DNA is calculated and displayed graphically. We conclude that the presence of the solvent as well as the details of the interaction geometry matter greatly in the determination of the stability of the DOX complexion. Ab initio calculations on realistic models are an important step towards a more accurate description of biomolecular interaction and in the eventual understanding of long-range interactions in biomolecular systems.

Electron induced inelastic and ionization cross section for plasma modeling

NASA Astrophysics Data System (ADS)

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.

Empirical Orthogonal Function (EOF) Analysis of Storm-Time GPS Total Electron Content Variations

NASA Astrophysics Data System (ADS)

Thomas, E. G.; Coster, A. J.; Zhang, S.; McGranaghan, R. M.; Shepherd, S. G.; Baker, J. B.; Ruohoniemi, J. M.

2016-12-01

Large perturbations in ionospheric density are known to occur during geomagnetic storms triggered by dynamic structures in the solar wind. These ionospheric storm effects have long attracted interest due to their impact on the propagation characteristics of radio wave communications. Over the last two decades, maps of vertically-integrated total electron content (TEC) based on data collected by worldwide networks of Global Positioning System (GPS) receivers have dramatically improved our ability to monitor the spatiotemporal dynamics of prominent storm-time features such as polar cap patches and storm enhanced density (SED) plumes. In this study, we use an empirical orthogonal function (EOF) decomposition technique to identify the primary modes of spatial and temporal variability in the storm-time GPS TEC response at midlatitudes over North America during more than 100 moderate geomagnetic storms from 2001-2013. We next examine the resulting time-varying principal components and their correlation with various geophysical indices and parameters in order to derive an analytical representation. Finally, we use a truncated reconstruction of the EOF basis functions and parameterization of the principal components to produce an empirical representation of the geomagnetic storm-time response of GPS TEC for all magnetic local times local times and seasons at midlatitudes in the North American sector.

Theoretical Calculations for Electron Impact Ionization of Atoms and Molecules

NASA Astrophysics Data System (ADS)

Amami, Sadek Mohamed Fituri

In the last twenty years, significant progress has been made for the theoretical treatment of electron impact ionization (e,2e) of atoms and molecules and, for some cases, very nice agreement between experiment and theory has been achieved. In particular, excellent agreement between theory and experiment and theory has been achieved for ionization of hydrogen and helium. However, agreement between experiment and theory is not nearly as good for ionization of larger atoms and molecules. In the first part of this dissertation, different theoretical approaches will be employed to study the triply differential cross section (TDCS) for low and intermediate energy electron-impact ionization of Neon and Argon for different orbital states. There is a very recent interest in studying ionization of Laser aligned atoms in order to get a better understanding about electron impact ionization of molecules. In the next part of this dissertation, results will be presented for electron-impact ionization of three laser aligned atoms, Mg, Ca, and Na. The comparison between the theory and experiment showed that our three body distorted wave (3DW) model gave excellent agreement with experiment in the scattering plane but very poor agreement perpendicular to the scattering plane. An explanation for this poor agreement out of the scattering plane has been provided by comparing our theoretical results with those of the time depended close coupling (TDCC) model and this explanation is also provided in this dissertation. Recently, significant attention has been directed towards obtaining a better under-standing of electron-impact ionization of molecules which are significantly more challenging than atoms. In the last part of this dissertation, results will be presented for electron-impact ionization of three different molecules (N2 , H2O, and CH4) which have been studied comprehensively using different theoretical approximations for different types of geometries. The published papers in section two contain a detailed analysis and discussion for each of these topics.

TID Simulation of Advanced CMOS Devices for Space Applications

NASA Astrophysics Data System (ADS)

Sajid, Muhammad

2016-07-01

This paper focuses on Total Ionizing Dose (TID) effects caused by accumulation of charges at silicon dioxide, substrate/silicon dioxide interface, Shallow Trench Isolation (STI) for scaled CMOS bulk devices as well as at Buried Oxide (BOX) layer in devices based on Silicon-On-Insulator (SOI) technology to be operated in space radiation environment. The radiation induced leakage current and corresponding density/concentration electrons in leakage current path was presented/depicted for 180nm, 130nm and 65nm NMOS, PMOS transistors based on CMOS bulk as well as SOI process technologies on-board LEO and GEO satellites. On the basis of simulation results, the TID robustness analysis for advanced deep sub-micron technologies was accomplished up to 500 Krad. The correlation between the impact of technology scaling and magnitude of leakage current with corresponding total dose was established utilizing Visual TCAD Genius program.

Ionospheric effects over Europe during the solar eclipse on 20 March 2015

NASA Astrophysics Data System (ADS)

Hoque, Mainul; Jakowski, Norbert; Berdermann, Jens

2017-04-01

A total solar eclipse occurred on March 20, 2015 moving from the North-West Europe towards the North-East. Due to strong solar radiation changes dynamic processes were initiated in the atmosphere and ionosphere causing a measurable impact e.g. on the temperature and ionization during the eclipse. We analyzed the 20 March 2015 solar eclipse effects on the ionospheric structure over Europe using multi-sensor observations such as vertical sounding (VS) and Global Positioning System (GPS) measurements. Whereas the VS measurements are used to provide peak electron density information at the ionospheric F2, F1 and E layers over selected ionosonde stations, a dense network of GPS stations is used to provide high spatial resolution of the total electron content (TEC) estimates over Europe. We reconstructed the TEC maps with 5 minutes time resolution and thus investigated the original TEC maps and differential TEC maps obtained by subtracting 27 days medians from the actual TEC map values on 20 March 2015. By combining VS and GPS measurements the equivalent slab thickness has been estimated over several ionosonde stations to get information how the shape of the vertical electron density profile changes during the eclipse. The analysis of the solar eclipse on 20 March 2015 presented here will contribute to understand the ionospheric response on solar eclipses occurring at different latitudes. The observations indicate that a number of competitive processes initiated by an eclipse are often enhanced by dynamic forces associated with large scale geophysical conditions not directly impacted by the solar eclipse. Our TEC estimation shows that the total ionization reduces up to 60% (after bias correction 40%) as a function of obscuration. Since the 20 March 2015 eclipse occurred during the negative phase of a severe geomagnetic storm on 17 March 2015, the observed TEC depletion is higher than those reported earlier for 1999 and 2005 eclipses. Thus, a negative bias of up to 20% was observed over Northern Europe already before the eclipse occurred. Moreover, the eclipse path of the solar eclipse in 2015 is traced at higher latitudes compared with eclipses observed in the years 1999 and 2005. The ionospheric response to the obscuration function is delayed up to 40 minutes decreasing with growing distance from the totality zone and increasing with altitude. The increasing delay with altitude is in agreement with earlier findings for other eclipses. The equivalent slab thickness was found to increase by approximately 80 -100 km during the solar eclipse on 20 March 2015 showing evidence for a pronounced loss in the bottomside ionosphere causing a delayed depletion of the topside ionosphere.

Electron Processing at 50 eV of Terphenylthiol Self-Assembled Monolayers: Contributions of Primary and Secondary Electrons.

PubMed

Houplin, Justine; Dablemont, Céline; Sala, Leo; Lafosse, Anne; Amiaud, Lionel

2015-12-22

Aromatic self-assembled monolayers (SAMs) can serve as platforms for development of supramolecular assemblies driven by surface templates. For many applications, electron processing is used to locally reinforce the layer. To achieve better control of the irradiation step, chemical transformations induced by electron impact at 50 eV of terphenylthiol SAMs are studied, with these SAMs serving as model aromatic SAMs. High-resolution electron energy loss spectroscopy (HREELS) and electron-stimulated desorption (ESD) of neutral fragment measurements are combined to investigate electron-induced chemical transformation of the layer. The decrease of the CH stretching HREELS signature is mainly attributed to dehydrogenation, without a noticeable hybridization change of the hydrogenated carbon centers. Its evolution as a function of the irradiation dose gives an estimate of the effective hydrogen content loss cross-section, σ = 2.7-4.7 × 10(-17) cm(2). Electron impact ionization is the major primary mechanism involved, with the impact electronic excitation contributing only marginally. Therefore, special attention is given to the contribution of the low-energy secondary electrons to the induced chemistry. The effective cross-section related to dissociative secondary electron attachment at 6 eV is estimated to be 1 order of magnitude smaller. The 1 eV electrons do not induce significant chemical modification for a 2.5 mC cm(-2) dose, excluding their contribution.

Environmental Life Cycle Techniques for New Weapons Acquisition Systems

DTIC Science & Technology

2004-09-01

Amount) Total grenade War Caracterisation factors (MJ/nn) Unit (Impact indicator) Total grenade War Total of all compartments MJ 59200 82700... Caracterisation factors (Kg CFC11 eq/nn) Unit (Impact indicator) Total grenade War Total of all compartments kg CFC-11 0,000429 0,00046 Remaining...Substance Compartment Unit (Amount) Total grenade War Caracterisation factors (Kg C2H2/nn) Unit (Impact indicator) Total grenade War Total of all

Nonequilibrium calculations of the role of electron impact in the production of NO and its emissions

NASA Astrophysics Data System (ADS)

Campbell, L.; Brunger, M. J.

2009-04-01

We review our recent work on nonequilibrium modelling of the density of nitric oxide and its infrared emissions in the Earth's upper atmosphere. The aim of these studies was to investigate the contribution of electron impact excitation to the NO density and the sensitivity of this process to the electron impact cross sections. The results are compared with satellite measurements of NO densities in equatorial and auroral high-latitude conditions and with rocket measurements of infrared emissions in auroral conditions. Particular findings are that electron impact excitation of N2 makes a significant contribution to the NO density at altitudes around 105 km and to auroral infrared emissions for the (1 → 0) ground-state emission from NO. The sensitivity of the NO fundamental emissions to various measured and theoretical integral cross sections is investigated and found to be significant.

High Resolution Emission Spectroscopy of the Alpha Pi-1 - Chi Sigma-1(+) Fourth Positive Band System of CO from Electron Impact

NASA Technical Reports Server (NTRS)

Beegle, Luther W.; Ajello, Joseph M.; James, Geoffrey K.; Alvarez, Marcos; Dziczek, Dariusz

2000-01-01

We report electron-impact induced fluorescence spectra [300 mA full width at half maximum (FWHM)] of CO for 20 and 100 eV impact energies of the spectral region of 1300 to 2050 A and high resolution spectra (FWHM) of the v'=5 to v"=l and the v'=3 to v"=O bands showing that the rotational structure of the band system are modeled accurately. The excitation function of the (0,1) band (1597 A) was measured from electron impact in the energy range from threshold to 750 eV and placed on an absolute scale from modem calibration standards.

Application of the BEf-scaling approach to electron impact excitation of diople-allowed electronic states in molecules

NASA Astrophysics Data System (ADS)

Brunger, M. J.; Thorn, P. A.; Campbell, L.; Kato, H.; Kawahara, H.; Hoshino, M.; Tanaka, H.; Kim, Y.-K.

2008-05-01

We consider the efficacy of the BEf-scaling approach, in calculating reliable integral cross sections for electron impact excitation of dipole-allowed electronic states in molecules. We will demonstrate, using specific examples in H2, CO and H2O, that this relatively simple procedure can generate quite accurate integral cross sections which compare well with available experimental data. Finally, we will briefly consider the ramifications of this to atmospheric and other types of modelling studies.

Total Ionizing Dose and Displacement Damage Compendium of Candidate Spacecraft Electronics for NASA

NASA Technical Reports Server (NTRS)

Cochran, Donna J.; Chen, Dakai; Oldham, Timothy R.; Sanders, Anthony B.; Kim, Hak S.; Campola, Michael J.; Buchner, Stephen P.; LaBel, Kenneth A.; Marshall, Cheryl J.; Pellish, Jonathan A.;

Nitric oxide excited under auroral conditions: Excited state densities and band emissions

NASA Astrophysics Data System (ADS)

Cartwright, D. C.; Brunger, M. J.; Campbell, L.; Mojarrabi, B.; Teubner, P. J. O.

2000-09-01

Electron impact excitation of vibrational levels in the ground electronic state and nine excited electronic states in NO has been simulated for an IBC II aurora (i.e., ˜10 kR in 3914 Å radiation) in order to predict NO excited state number densities and band emission intensities. New integral electron impact excitation cross sections for NO were combined with a measured IBC II auroral secondary electron distribution, and the vibrational populations of 10 NO electronic states were determined under conditions of statistical equilibrium. This model predicts an extended vibrational distribution in the NO ground electronic state produced by radiative cascade from the seven higher-lying doublet excited electronic states populated by electron impact. In addition to significant energy storage in vibrational excitation of the ground electronic state, both the a 4Π and L2 Φ excited electronic states are predicted to have relatively high number densities because they are only weakly connected to lower electronic states by radiative decay. Fundamental mode radiative transitions involving the lowest nine excited vibrational levels in the ground electronic state are predicted to produce infrared (IR) radiation from 5.33 to 6.05 μm with greater intensity than any single NO electronic emission band. Fundamental mode radiative transitions within the a 4Π electronic state, in the 10.08-11.37 μm region, are predicted to have IR intensities comparable to individual electronic emission bands in the Heath and ɛ band systems. Results from this model quantitatively predict the vibrational quantum number dependence of the NO IR measurements of Espy et al. [1988].

A model providing long-term data sets of energetic electron precipitation during geomagnetic storms

NASA Astrophysics Data System (ADS)

van de Kamp, M.; Seppälä, A.; Clilverd, M. A.; Rodger, C. J.; Verronen, P. T.; Whittaker, I. C.

2016-10-01

The influence of solar variability on the polar atmosphere and climate due to energetic electron precipitation (EEP) has remained an open question largely due to lack of a long-term EEP forcing data set that could be used in chemistry-climate models. Motivated by this, we have developed a model for 30-1000 keV radiation belt driven EEP. The model is based on precipitation data from low Earth orbiting POES satellites in the period 2002-2012 and empirically described plasmasphere structure, which are both scaled to a geomagnetic index. This geomagnetic index is the only input of the model and can be either Dst or Ap. Because of this, the model can be used to calculate the energy-flux spectrum of precipitating electrons from 1957 (Dst) or 1932 (Ap) onward, with a time resolution of 1 day. Results from the model compare well with EEP observations over the period of 2002-2012. Using the model avoids the challenges found in measured data sets concerning proton contamination. As demonstrated, the model results can be used to produce the first ever >80 year long atmospheric ionization rate data set for radiation belt EEP. The impact of precipitation in this energy range is mainly seen at altitudes 70-110 km. The ionization rate data set, which is available for the scientific community, will enable simulations of EEP impacts on the atmosphere and climate with realistic EEP variability. Due to limitations in this first version of the model, the results most likely represent an underestimation of the total EEP effect.

Evaluation of Arabic Language Learning Program for Non-Native Speakers in Saudi Electronic University According to Total Quality Standards

ERIC Educational Resources Information Center

Alowaydhi, Wafa Hafez

2016-01-01

The current study aimed at standardizing the program of learning Arabic for non-native speakers in Saudi Electronic University according to certain standards of total quality. To achieve its purpose, the study adopted the descriptive analytical method. The author prepared a measurement tool for evaluating the electronic learning programs in light…

Total-dose radiation effects data for semiconductor devices (1989 supplement)

NASA Technical Reports Server (NTRS)

Martin, Keith E.; Coss, James R.; Goben, Charles A.; Shaw, David C.; Farmanesh, Sam; Davarpanah, Michael M.; Craft, Leroy H.; Price, William E.

1990-01-01

Steady state, total dose radiation test data are provided for electronic designers and other personnel using semiconductor devices in a radiation environment. The data are presented in graphic and narrative formats. Two primary radiation source types were used: Cobalt-60 gamma rays and a Dynamitron electron accelerator capable of delivering 2.5 MeV electrons at a steady rate.

Electron- and positron-impact ionization of inert gases

NASA Astrophysics Data System (ADS)

Campeanu, R. I.; Walters, H. R. J.; Whelan, Colm T.

2018-06-01

Triple-differential cross sections (TDCS) are presented for the electron and positron impact ionization of inert gas atoms in a range of geometries where a number of significant few body effects compete to define the shape of the TDCS. Using both positrons and electrons as projectiles has opened up the possibility of performing complementary studies which could effectively isolate competing interactions which cannot be separately detected in an experiment with a single projectile. A comparison is presented between theory and the recent experiments of [Gavin, deLucio, and DuBois, Phys. Rev. A 95, 062703 (2017), 10.1103/PhysRevA.95.062703] for e± and contrasted with the results from earlier electron experiments. For the special case of xenon(5 p ), cross sections are presented for both electron- and positron-impact ionization in kinematics where the electron case appears well understood. The kinematics are then varied in order to focus on the possible role of distortion, exchange, and target wave-function effects.

Multiple electron processes of He and Ne by proton impact

NASA Astrophysics Data System (ADS)

Terekhin, Pavel Nikolaevich; Montenegro, Pablo; Quinto, Michele; Monti, Juan; Fojon, Omar; Rivarola, Roberto

2016-05-01

A detailed investigation of multiple electron processes (single and multiple ionization, single capture, transfer-ionization) of He and Ne is presented for proton impact at intermediate and high collision energies. Exclusive absolute cross sections for these processes have been obtained by calculation of transition probabilities in the independent electron and independent event models as a function of impact parameter in the framework of the continuum distorted wave-eikonal initial state theory. A binomial analysis is employed to calculate exclusive probabilities. The comparison with available theoretical and experimental results shows that exclusive probabilities are needed for a reliable description of the experimental data. The developed approach can be used for obtaining the input database for modeling multiple electron processes of charged particles passing through the matter.

Impact of state-specific flowfield modeling on atomic nitrogen radiation

NASA Astrophysics Data System (ADS)

Johnston, Christopher O.; Panesi, Marco

2018-01-01

A hypersonic flowfield model that treats electronic levels of the dominant afterbody radiator N as individual species is presented. This model allows electron-ion recombination rate and two-temperature modeling improvements, the latter which are shown to decrease afterbody radiative heating by up to 30%. This decrease is primarily due to the addition of the electron-impact excitation energy-exchange term to the energy equation governing the vibrational-electronic electron temperature. This model also allows the validity of the often applied quasi-steady-state (QSS) approximation to be assessed. The QSS approximation is shown to fail throughout most of the afterbody region for lower electronic states, although this impacts the radiative intensity reaching the surface by less than 15%. By computing the electronic-state populations of N within the flowfield solver, instead of through the QSS approximation in the radiation solver, the coupling of nonlocal radiative transition rates to the species continuity equations becomes feasible. Implementation of this higher-fidelity level of coupling between the flowfield and radiation solvers is shown to increase the afterbody radiation by up to 50% relative to the conventional model.

Potential resource and toxicity impacts from metals in waste electronic devices.

PubMed

Woo, Seung H; Lee, Dae Sung; Lim, Seong-Rin

2016-04-01

As a result of the continuous release of new electronic devices, existing electronic devices are quickly made obsolete and rapidly become electronic waste (e-waste). Because e-waste contains a variety of metals, information about those metals with the potential for substantial environmental impact should be provided to manufacturers, recyclers, and disposers to proactively reduce this impact. This study assesses the resource and toxicity (i.e., cancer, noncancer, and ecotoxicity) potentials of various heavy metals commonly found in e-waste from laptop computers, liquid-crystal display (LCD) monitors, LCD TVs, plasma TVs, color cathode ray tube (CRT) TVs, and cell phones and then evaluates such potentials using life cycle impact-based methods. Resource potentials derive primarily from Cu, Sb, Ag, and Pb. Toxicity potentials derive primarily from Pb, Ni, and Hg for cancer toxicity; from Pb, Hg, Zn, and As for noncancer toxicity; and from Cu, Pb, Hg, and Zn for ecotoxicity. Therefore, managing these heavy metals should be a high priority in the design, recycling, and disposal stages of electronic devices. © 2015 SETAC.

Hazards by meteoroid Impacts onto operational spacecraft

NASA Astrophysics Data System (ADS)

Landgraf, M.; Jehn, R.; Flury, W.

Operational spacecraft in Earth orbit or on interplanetary trajectories are exposed to high-velocity particles that can cause damage to sensitive on-board instrumentation. In general there are two types of hazard: direct destruction of functional elements by impacts, and indirect disturbance of instruments by the generated impact plasma. The latter poses a threat especially for high-voltage instrumentation and electronics. While most meteoroids have sizes in the order of a few micrometre, and typical masses of 10-15 kg, the most dangerous population with sizes in the millimetre and masses in the milligramme range exhibits still substantial impact fluxes in the order of 2 × 10-11 m-2 s-1 . This level of activity can by significantly elevated during passages of the spacecraft through cometary trails, which on Earth cause events like the well-known Leonid and Perseid meteor streams. The total mass flux of micrometeoroids onto Earth is about 107 kg yr-1 , which is about one order of magnitude less than the estimated mass flux of large objects like comets and asteroids with individual masses above 105 kg. In order to protect spacecraft from the advert effects of meteoroid impacts, ESA performs safety operations on its spacecraft during meteor streams, supported by real-time measurements of the meteor activity. A summary of past and future activities is given.

The Pocketable Electronic Devices in Radiation Oncology (PEDRO) Project: How the Use of Tools in Medical Decision Making is Changing?

PubMed

De Bari, Berardino; Franco, Pierfrancesco; Niyazi, Maximilian; Cornetto, Andrea Peruzzo; Qvortrup, Camilla; Martin, Arturo Navarro; Cacicedo, Jon; Fernandez, Gonçalo; Louro, Luís Vasco; Lestrade, Laëtitia; Ciammella, Patrizia; Greto, Daniela; Checkrine, Tarik; Youssef, Elkholti; Filippi, Andrea Riccardo; Poulsen, Laurids Østergaard; Alongi, Filippo

2016-04-01

To analyze the impact of mobile electronic devices (MEDs) and apps in the daily clinical activity of young radiation or clinical oncologists in 5 Western European countries (Italy, Germany, Spain, Portugal, and Denmark). A web-based questionnaire was sent to 462 young (≤40 years) members of the national radiation or clinical oncology associations of the countries involved in the study. The 15 items investigated diffusion of MEDs (smartphones and/or tablets), their impact on daily clinical activity, and the differences perceived by participants along time. A total of 386 (83.5%) of the 462 correctly filled questionnaires were statistically evaluated. Up to 65% of respondents declared to use an electronic device during their clinical activity. Conversely, 72% considered low to moderate impact of smartphones/tables on their daily practice. The daily use significantly increased from 2009 to 2012: users reporting a use ≥6 times/d raised from 5% to 39.9%. Professional needs fulfillment was declared by less than 68% of respondents and compliance to apps indications by 66%. Significant differences were seen among the countries, in particular concerning the feeling of usefulness of MEDs in the daily clinical life. The perception of the need of a comprehensive Web site containing a variety of applications (apps) for clinical use significantly differed among countries in 2009, while it was comparable in 2012. This survey showed a large diffusion of MEDs in young professionals working in radiation oncology. Looking at these data, it is important to verify the consistency of information found within apps, in order to avoid potential errors eventually detrimental for patients. "Quality assurance" criteria should be specifically developed for medical apps and a comprehensive Web site gathering all reliable applications and tools might be useful for daily clinical practice. © The Author(s) 2015.

Benchmark study for total enery electrons in thick slabs

NASA Technical Reports Server (NTRS)

Jun, I.

2002-01-01

The total energy deposition profiles when highenergy electrons impinge on a thick slab of elemental aluminum, copper, and tungsten have been computed using representative Monte Carlo codes (NOVICE, TIGER, MCNP), and compared in this paper.

Recent Total Ionizing Dose and Displacement Damage Compendium of Candidate Electronics for NASA Space Systems

NASA Technical Reports Server (NTRS)

Cochran, Donna J.; Boutte, Alvin J.; Campola, Michael J.; Carts, Martin A.; Casey, Megan C.; Chen, Dakai; LaBel, Kenneth A.; Ladbury, Raymond L.; Lauenstein, Jean-Marie; Marshall, Cheryl J.;

Technology Trumping Sleep: Impact of Electronic Media and Sleep in Late Adolescent Students

ERIC Educational Resources Information Center

Moulin, Kerry L.; Chung, Chia-Jung

2017-01-01

The purpose of this research study was to explore with what impact evening media use interfered with either schoolwork and/or sufficient healthy sleep. In addition, the study examined with what impact there may be a compromise in students' ability or aptitude for positive academic success, related to either lack of sleep or electronic media use.…

Carbon contamination in scanning transmission electron microscopy and its impact on phase-plate applications.

PubMed

Hettler, Simon; Dries, Manuel; Hermann, Peter; Obermair, Martin; Gerthsen, Dagmar; Malac, Marek

2017-05-01

We analyze electron-beam induced carbon contamination in a transmission electron microscope. The study is performed on thin films potentially suitable as phase plates for phase-contrast transmission electron microscopy. Electron energy-loss spectroscopy and phase-plate imaging is utilized to analyze the contamination. The deposited contamination layer is identified as a graphitic carbon layer which is not prone to electrostatic charging whereas a non-conductive underlying substrate charges. Several methods that inhibit contamination are evaluated and the impact of carbon contamination on phase-plate imaging is discussed. The findings are in general interesting for scanning transmission electron microscopy applications. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Three-dimensional multi-fluid simulations of Titan's interaction with Saturn's magnetosphere: Comparisons with Cassini's T55 flyby

NASA Astrophysics Data System (ADS)

Snowden, D.; Winglee, R.

2013-08-01

We describe a new multi-fluid model of Titan's interaction with Saturn's magnetosphere that includes finer resolution in Titan's ionosphere, photoionization, electron-impact ionization, dissociative recombination, and ion-neutral coupling in the momentum and energy equations. We compare simulation results to data from Cassini's T55 flyby to show that including magnetospheric electron-impact ionization in Titan's nightside ionosphere is necessary to calculate electron densities, electron temperatures, and ion velocities that are consistent with Cassini observations. However, similar to other studies, we find that the electron-impact ionization rate calculated by the model needs to be significantly reduced to produce an electron density that is in agreement with the observations. We also find that an upstream plasma flow with significant components northward and radially outward from Saturn is needed to reproduce the gradual increase in electron density observed during the ingress portion of T55. This suggests that Titan was in a nonideal environment with a plasma flow oriented away from the direction of corotation during T55 and likely during the subsequent flybys T56, T57, T58, and T59 when similar electron density enhancements were seen on the inbound portion of Cassini's trajectory.

Electron-impact excitation of the BΣ1u+ and CΠ1u electronic states of H2

NASA Astrophysics Data System (ADS)

Kato, H.; Kawahara, H.; Hoshino, M.; Tanaka, H.; Campbell, L.; Brunger, M. J.

2008-06-01

Differential and integral cross sections for electron-impact excitation of the dipole-allowed BΣ1u+ and CΠ1u electronic states of molecular hydrogen have been measured. The differential cross sections were determined by analysis of normalized energy-loss spectra obtained using a crossed-beam apparatus at the electron-impact energies of 40, 100, and 200 eV. Integral cross sections were subsequently derived from these data. The present work was undertaken in order to investigate some ambiguities between earlier experimental data and recent BEf-scaled cross sections as defined and calculated by Kim [J. Chem. Phys. 126, 064305 (2007)] and also to extend the energy range of the available data. Optical oscillator strengths, also determined as a part of the present investigation, were found to be in fair accordance with previous measurements and some calculations.

A Survey of Electron Impact Cross-Sections for Halogens and Halogen Compounds of Interest to Plasma Processing

NASA Technical Reports Server (NTRS)

Sharma, S. P.; Rao, M. V. V. S.; Arnold, James O. (Technical Monitor)

1998-01-01

Published electron impact cross section data on halogens Cl2, F2, and halogen containing compounds such as Cx Fy, HCl, Cx Cly Fz are reviewed and critically evaluated based on the information provided by various researchers. The present work reports data on electron impact excitation, ionization, dissociation, electron attachment, electron detachment, and photo detachment. Elastic scattering cross sections and data on bulk properties such as diffusion coefficients in various background gases are also evaluated. Since some of the cross sectional data is derived from indirect measurements such as drift velocity, care has been taken to reconcile the differences among the reported data with due attention to the measurement technique. In conclusion, the processes with no or very limited amount of data and questionable set of data are identified and recommendation for further research direction is made.

Missed surgical intensive care unit billing: potential financial impact of 24/7 faculty presence.

PubMed

Hendershot, Kimberly M; Bollins, John P; Armen, Scott B; Thomas, Yalaunda M; Steinberg, Steven M; Cook, Charles H

2009-07-01

To efficiently capture evaluation and management (E&M) and procedural billing in our surgical intensive care unit (SICU), we have developed an electronic billing system that links to the electronic medical record (EMR). In this system, only notes electronically signed and coded by an attending generate billing charges. We hypothesized that capture of missed billing during nighttime and weekends might be sufficient to subsidize 24/7 in-house attending coverage. A retrospective chart EMR review was performed of the EMRs for all SICU patients during a 2-month period. Note type, date, time, attending signature, and coding were analyzed. Notes without attending signature, diagnosis, or current procedural terminology (CPT) code were considered incomplete and identified as "missed billing." Four hundred and forty-three patients had 465 admissions generating 2,896 notes. Overall, 76% of notes were signed and coded by an attending and billed. Incomplete (not billed) notes represented an overall missed billing opportunity of $159,138 for the 2-month time period (approximately $954,000 annually). Unbilled E&M encounters during weekdays totaled $54,758, whereas unbilled E&M and procedures from weeknights and weekends totaled $88,408 ($44,566 and $43,842, respectively). Missed billing after-hours thus represents approximately $530K annually, extrapolating to approximately $220K in collections from our payer mix. Surprisingly, missed E&M and procedural billing during weekdays totaled $70,730 (approximately $425K billing, approximately $170K collections annually), and typically represented patients seen, but transferred from the SICU before attending documentation was completed. Capture of nighttime and weekend ICU collections alone may be insufficient to add faculty or incentivize in-house coverage, but could certainly complement other in-house derived revenues to such ends. In addition, missed daytime billing in busy modern ICUs can be substantial, and use of an EMR to identify missed billing opportunities can help create solutions to recover these revenues.

Development of CPR security using impact analysis.

PubMed Central

Salazar-Kish, J.; Tate, D.; Hall, P. D.; Homa, K.

2000-01-01

The HIPAA regulations will require that institutions ensure the prevention of unauthorized access to electronically stored or transmitted patient records. This paper discusses a process for analyzing the impact of security mechanisms on users of computerized patient records through "behind the scenes" electronic access audits. In this way, those impacts can be assessed and refined to an acceptable standard prior to implementation. Through an iterative process of design and evaluation, we develop security algorithms that will protect electronic health information from improper access, alteration or loss, while minimally affecting the flow of work of the user population as a whole. PMID:11079984

Calculation of effective atomic number and electron density of essential biomolecules for electron, proton, alpha particle and multi-energetic photon interactions

NASA Astrophysics Data System (ADS)

Kurudirek, Murat; Onaran, Tayfur

2015-07-01

Effective atomic numbers (Zeff) and electron densities (Ne) of some essential biomolecules have been calculated for total electron interaction, total proton interaction and total alpha particle interaction using an interpolation method in the energy region 10 keV-1 GeV. Also, the spectrum weighted Zeff for multi-energetic photons has been calculated using Auto-Zeff program. Biomolecules consist of fatty acids, amino acids, carbohydrates and basic nucleotides of DNA and RNA. Variations of Zeff and Ne with kinetic energy of ionizing charged particles and effective photon energies of heterogeneous sources have been studied for the given materials. Significant variations in Zeff and Ne have been observed through the entire energy region for electron, proton and alpha particle interactions. Non-uniform variation has been observed for protons and alpha particles in low and intermediate energy regions, respectively. The maximum values of Zeff have found to be in higher energies for total electron interaction whereas maximum values have found to be in relatively low energies for total proton and total alpha particle interactions. When it comes to the multi-energetic photon sources, it has to be noted that the highest Zeff values were found at low energy region where photoelectric absorption is the pre-dominant interaction process. The lowest values of Zeff have been shown in biomolecules such as stearic acid, leucine, mannitol and thymine, which have highest H content in their groups. Variation in Ne seems to be more or less the same with the variation in Zeff for the given materials as expected.

Technology and medication errors: impact in nursing homes.

PubMed

Baril, Chantal; Gascon, Viviane; St-Pierre, Liette; Lagacé, Denis

2014-01-01

The purpose of this paper is to study a medication distribution technology's (MDT) impact on medication errors reported in public nursing homes in Québec Province. The work was carried out in six nursing homes (800 patients). Medication error data were collected from nursing staff through a voluntary reporting process before and after MDT was implemented. The errors were analysed using: totals errors; medication error type; severity and patient consequences. A statistical analysis verified whether there was a significant difference between the variables before and after introducing MDT. The results show that the MDT detected medication errors. The authors' analysis also indicates that errors are detected more rapidly resulting in less severe consequences for patients. MDT is a step towards safer and more efficient medication processes. Our findings should convince healthcare administrators to implement technology such as electronic prescriber or bar code medication administration systems to improve medication processes and to provide better healthcare to patients. Few studies have been carried out in long-term healthcare facilities such as nursing homes. The authors' study extends what is known about MDT's impact on medication errors in nursing homes.

The trend of quality of publications in endodontic surgery: a 10-year systematic survey of the literature.

PubMed

Del Fabbro, Massimo; Corbella, Stefano; Tsesis, Igor; Taschieri, Silvio

2015-03-01

The aims of the present systematic literature analysis were to evaluate, over a 10-year period, the trend of the proportion of RCT, SR, MA published on endodontic surgery, and to investigate if the impact factor (IF) of the main endodontic Journals correlates with the proportion of RCT, SR, MA they publish. An electronic search of the RCT, SR and MA published on the topic "endodontic surgery" from 2001 to 2010 was performed on Medline and Cochrane CENTRAL database using specific search terms combined with Boolean operators. Endodontic Journals impact factor was retrieved by the Thomson Scientific database. The proportion of each study type over the total number of articles on endodontic surgery published per year was estimated. The correlation between the number of high-evidence level studies published on the main endodontic Journals and the IF of such Journals per year was estimated. From a total of 900 articles published in 2001-2010 on endodontic surgery, there were 114 studies of high evidence level. A significant increase of the proportion of either RCT, SR and MA over the years was found. A modest to unclear correlation was found between the Journal IF and the number of high-evidence articles published. There is a positive trend over the years among researchers in performing studies of good quality in endodontic surgery. The impact factor of endodontic Journals is not consistently influenced by publication of high-evidence level articles. Copyright © 2015 Elsevier Inc. All rights reserved.

Compendium of Current Total Ionizing Dose Results and Displacement Damage Results for Candidate Spacecraft Electronics for NASA

NASA Technical Reports Server (NTRS)

Cochran, Donna J.; O'Bryan, Martha V.; Buchner, Stephen P.; Poivey, Christian; Ladbury, Ray L.; LaBel, Kenneth A.

2007-01-01

Sensitivity of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage is studied. Devices tested include optoelectronics, digital, analog, linear bipolar devices, and hybrid devices.

Satellite observations of energetic electron precipitation during the 1979 solar eclipse and comparisons with rocket measurements

NASA Astrophysics Data System (ADS)

Gaines, E. E.; Imhof, W. L.; Voss, H. D.; Reagan, J. B.

1983-07-01

During the solar eclipse of 26 February 1979, the P78-1 satellite passed near Red Lake, Ontario, at an altitude of about 600 km. On two consecutive orbits spanning the time of total eclipse, energetic electrons were measured with two silicon solid state detector spectrometers having excellent energy and angular resolution. Significant fluxes of precipitating electrons were observed near the path of totality. Comparisons of flux intensities and energy spectra with those measured from a Nike Orion and two Nike Tomahawk rockets launched near Red Lake before and during total eclipse give good agreement and indicate that the electron precipitation was relatively uniform for more than an hour and over a broad geographical area.

Electron-impact excitation of the low-lying electronic states of HCN

NASA Technical Reports Server (NTRS)

Chutjian, A.; Tanaka, H.; Srivastava, S. K.; Wicke, B. G.

1977-01-01

The first study of the low-energy electron-impact excitation of low-lying electronic transitions in the HCN molecule is reported. Measurements were made at incident electron energies of 11.6 and 21.6 eV in the energy-loss range of 3-10 eV, and at scattering angles of 20-130 deg. Inelastic scattering spectra were placed on the absolute cross-section scale by determining first the ratio of inelastic-to-elastic scattering cross sections, and then separately measuring the absolute elastic scattering cross section. Several new electronic transitions are observed which are intrinsically overlapped in the molecule itself. Assignments of these electronic transitions are suggested. These assignments are based on present spectroscopic and cross-sections measurements, high-energy electron scattering spectra, optical absorption spectra, and ab initio molecular orbital calculations.

Clinical impact of 8 prospective, randomized, multicenter glaucoma trials.

PubMed

Panarelli, Joseph F; Banitt, Michael R; Sidoti, Paul A; Budenz, Donald L; Singh, Kuldev

2015-01-01

To determine the impact of 8 multicenter randomized clinical trials (RCTs) on glaucoma practice. An electronic survey was distributed to the members of the American Glaucoma Society (AGS). Each participant was asked 2 study-specific questions and 1 standard question common to all 8 RCTs assessing the study's impact on clinical practice. RCTs included in the survey were the Advanced Glaucoma Intervention Study (AGIS), Collaborative Initial Glaucoma Treatment Study (CIGTS), Collaborative Normal Tension Glaucoma (CNTG) Study, European Glaucoma Prevention Study (EGPS), Early Manifest Glaucoma Trial (EMGT), Glaucoma Laser Trial (GLT), Ocular Hypertension Treatment Study (OHTS), and Tube Versus Trabeculectomy (TVT) Study. A 5-point Likert scale was used for rating all responses. The practice setting and duration of glaucoma practice was determined for all AGS members who responded. A total of 206 (23.0%) of 894 AGS members participated in the survey. Among those who responded, 46.4% were self classified as academic practitioners and 53.6% worked in a private practice setting. Mean Likert scores for the standard question evaluating the overall impact of the RCT were OHTS 4.47, CNTG Study 4.13, AGIS 3.78, TVT Study 3.53, EMGT 3.48, CIGTS 3.44, GLT 3.39, and 2.69 EGPS. Substantial differences were observed in the clinical impact of several RCTs in glaucoma. The reported impact of each study likely reflects several factors including study timing, design, conduct, and interpretation of results.

Dichrometer errors resulting from large signals or improper modulator phasing.

PubMed

Sutherland, John C

2012-09-01

A single-beam spectrometer equipped with a photoelastic modulator can be configured to measure a number of different parameters useful in characterizing chemical and biochemical materials including natural and magnetic circular dichroism, linear dichroism, natural and magnetic fluorescence-detected circular dichroism, and fluorescence polarization anisotropy as well as total absorption and fluorescence. The derivations of the mathematical expressions used to extract these parameters from ultraviolet, visible, and near-infrared light-induced electronic signals in a dichrometer assume that the dichroic signals are sufficiently small that certain mathematical approximations will not introduce significant errors. This article quantifies errors resulting from these assumptions as a function of the magnitude of the dichroic signals. In the case of linear dichroism, improper modulator programming can result in errors greater than those resulting from the assumption of small signal size, whereas for fluorescence polarization anisotropy, improper modulator phase alone gives incorrect results. Modulator phase can also impact the values of total absorbance recorded simultaneously with linear dichroism and total fluorescence. Copyright © 2012 Wiley Periodicals, Inc., A Wiley Company.

Controlling the excitation process of free electrons by a femtosecond elliptically polarized laser

NASA Astrophysics Data System (ADS)

Gao, Lili; Wang, Feng; Jiang, Lan; Qu, Liangti; Lu, Yongfeng

2015-11-01

This paper is focused on the excitation rates of free electrons of an aluminum (Al) bulk irradiated by an elliptically polarized laser in simulation, using time-dependent density functional theory (TDDFT). The polarized 400 nm, 10 fs laser pulse consisted of two elementary sinusoidal beams, and is adjusted by changing the phase difference φ and the intersection angle θ of the polarization directions between the two beams. The simulation includes cases of φ = π/2 with θ = 30°, θ = 45°, θ = 60°, θ = 90°, θ = 120°, θ = 135°, θ = 150°, and cases of θ = 90° with φ = π/4, φ = π/3, φ = π/2, φ = 2π/3, φ = 3π/4. The absorbed energy, the excitation rates and the density distributions of free electrons after laser termination are investigated. At the given power intensity (1×1014Wcm-2), pulse width (10 fs) and wavelength (400 nm) of each elementary laser beam, computational results indicate that the excitation rate of free electrons is impacted by three major factors: the long axis direction of the laser projected profile, the amplitude difference of the first main oscillation (1st AD), and the total amplitude difference of main oscillations (TAD) of the external electric field. Among the aforementioned three factors for the excitation rate of free electrons, the direction of long axis plays the most significant role. The screen effect is crucial to compare the importance of the remaining two factors. The analysis approach to investigate the electron dynamics under an elliptically polarized laser is both pioneering and effective.

Head-Impact-Measurement Devices: A Systematic Review.

PubMed

O'Connor, Kathryn L; Rowson, Steven; Duma, Stefan M; Broglio, Steven P

2017-03-01

With an estimated 3.8 million sport- and recreation-related concussions occurring annually, targeted prevention and diagnostic methods are needed. Biomechanical analysis of head impacts may provide quantitative information that can inform both prevention and diagnostic strategies. To assess available head-impact devices and their clinical utility. We performed a systematic search of the electronic database PubMed for peer-reviewed publications, using the following phrases: accelerometer and concussion, head impact telemetry, head impacts and concussion and sensor, head impacts and sensor, impact sensor and concussion, linear acceleration and concussion, rotational acceleration and concussion, and xpatch concussion. In addition to the literature review, a Google search for head impact monitor and concussion monitor yielded 15 more devices. Included studies were performed in vivo, used commercially available devices, and focused on sport-related concussion. One author reviewed the title and abstract of each study for inclusion and exclusion criteria and then reviewed each full-text article to confirm inclusion criteria. Controversial articles were reviewed by all authors to reach consensus. In total, 61 peer-reviewed articles involving 4 head-impact devices were included. Participants in boxing, football, ice hockey, soccer, or snow sports ranged in age from 6 to 24 years; 18% (n = 11) of the studies included female athletes. The Head Impact Telemetry System was the most widely used device (n = 53). Fourteen additional commercially available devices were presented. Measurements collected by impact monitors provided real-time data to estimate player exposure but did not have the requisite sensitivity to concussion. Proper interpretation of previously reported head-impact kinematics across age, sport, and position may inform future research and enable staff clinicians working on the sidelines to monitor athletes. However, head-impact-monitoring systems have limited clinical utility due to error rates, designs, and low specificity in predicting concussive injury.

Collisional, radiative and total electron interaction in compound semiconductor detectors and solid state nuclear track detectors: effective atomic number and electron density.

PubMed

Kurudirek, Murat; Kurudirek, Sinem V

2015-05-01

Effective atomic numbers, Zeff and electron densities, Ne are widely used for characterization of interaction processes in radiation related studies. A variety of detectors are employed to detect different types of radiations i.e. photons and charged particles. In the present work, some compound semiconductor detectors (CSCD) and solid state nuclear track detectors (SSNTD) were investigated with respect to the partial as well as total electron interactions. Zeff and Ne of the given detectors were calculated for collisional, radiative and total electron interactions in the kinetic energy region 10keV-1GeV. Maximum values of Zeff and Ne were observed at higher kinetic energies of electrons. Significant variations in Zeff and Ne up to ≈20-25% were noticed for the detectors, GaN, ZnO, Amber and CR-39 for total electron interaction. Moreover, the obtained Zeff and Ne for electrons were compared to those obtained for photons in the entire energy region. Significant variations in Zeff were also noted not only for photons (up to ≈40% for GaN) but also between photons and electrons (up to ≈60% for CR-39) especially at lower energies. Except for the lower energies, Zeff and Ne keep more or less constant values for the given materials. The energy regions where Zeff and Ne keep constant clearly show the availability of using these parameters for characterization of the materials with respect to the radiation interaction processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Compendium of Current Total Ionizing Dose and Displacement Damage Results from NASA Goddard Space Flight Center and NASA Electronic Parts and Packaging Program

NASA Technical Reports Server (NTRS)

Topper, Alyson D.; Campola, Michael J.; Chen, Dakai; Casey, Megan C.; Yau, Ka-Yen; Cochran, Donna J.; Label, Kenneth A.; Ladbury, Raymond L.; Mondy, Timothy K.; O'Bryan, Martha V.;

Measurements of Electron Impact Excitation Cross Sections at the Harvard-Smithsonian Center for Astrophysics

NASA Technical Reports Server (NTRS)

Gardner, L. D.; Kohl, J. L.

2006-01-01

The analysis of absolute spectral line intensities and intensity ratios with spectroscopic diagnostic techniques provides empirical determinations of chemical abundances, electron densities and temperatures in astrophysical objects. Since spectral line intensities and their ratios are controlled by the excitation rate coefficients for the electron temperature of the observed astrophysical structure, it is imperative that one have accurate values for the relevant rate coefficients. Here at the Harvard-Smithsonian Center for Astrophysics, we have been carrying out measurements of electron impact excitation (EIE) for more than 25 years.

LABCEDE Fluorescence Investigations

DTIC Science & Technology

1988-08-01

the B state is preferentially formed in lower energy spin states, either by direct electron impact or by radiative cascade. However, comparison with dir... impact excitation cross sections for these states at 4.5 kV are small and much of the excitation comes from lower energy secondary electrons created by... impact and energy pooling are significantly different. Experimentally, the C-state vibrational distribution is accurately determined from the spectrum

Understanding the Impact of Return-Current Losses on the X-Ray Emission from Solar Flares

NASA Technical Reports Server (NTRS)

Holman, Gordon D.

2012-01-01

I obtain and examine the implications of one-dimensional analytic solutions for return-current losses on an initially power-law distribution of energetic electrons with a sharp low-energy cutoff in flare plasma with classical (collisional) resistivity. These solutions show, for example, that return-current losses are not sensitive to plasma density, but are sensitive to plasma temperature and the low energy cutoff of the injected nonthermal electron distribution. A characteristic distance from the electron injection site, x(sub rc), is derived. At distances less than x(sub rc) the electron flux density is not reduced by return-current losses, but plasma heating can be substantial in this region, in the upper, coronal part of the flare loop. Before the electrons reach the collisional thick-target region of the flare loop, an injected power-law electron distribution with a low-energy cutoff maintains that structure, but with a flat energy distribution below the cutoff energy, which is now determined by the total potential drop experienced by the electrons. Modifications due to the presence of collisional losses are discussed. I compare these results with earlier analytical results and with more recent numerical simulations. Emslie's 1980 conjecture that there is a maximum integrated X-ray source brightness on the order of 10(exp -15) photons per square centimeter per second per square centimeter is examined. I find that this is not actually a maximum brightness and its value is parameter dependent, but it is nevertheless a valuable benchmark for identifying return-current losses in hard X-ray spectra. I discuss an observational approach to identifying return-current losses in flare data, including identification of a return-current "bump" in X-ray light curves at low photon energies.

Continuous monitoring of odours from a composting plant using electronic noses.

PubMed

Sironi, Selena; Capelli, Laura; Céntola, Paolo; Del Rosso, Renato; Il Grande, Massimiliano

2007-01-01

The odour impact of a composting plant situated in an urbanized area was evaluated by continuously monitoring the ambient air close to the plant during a period of about 4 days using two electronic noses. One electronic nose was installed in a nearby house, and the other one inside the perimeter of the composting plant in order to compare the response of both instruments. The results of the monitoring are represented by tables that report the olfactory class and the odour concentration value attributed to the analyzed air for each of the 370 measurements carried out during the monitoring period. The electronic nose installed at the house detected the presence of odours coming from the composting plant for about 7.8% of the monitoring total duration. Of the odour detections, 86% (25 of 29 measurements) were classified as belonging to the olfactory class corresponding to the open air storage of the waste screening overflows heaps, which was therefore identified to be the major odour source of the monitored composting plant. In correspondence of the measurements during which the electronic nose inside the house detected the presence of odours from the composting plant, the olfactory classes recognized by both instruments coincide. Moreover, the electronic nose at the house detected the presence of odours from the composting plant at issue in correspondence of each odour perception of the house occupants. The results of the study show the possibility of using an electronic nose for environmental odours monitoring, which enables the classification of the quality of the air and to quantify the olfactory nuisance from an industrial source in terms of duration and odour concentration.

Total electron scattering cross sections of some important biomolecules at 0.2-6.0 keV energies

NASA Astrophysics Data System (ADS)

Gurung, Meera Devi; Ariyasinghe, W. M.

2017-12-01

The total electron scattering cross sections (TCS) of five nucleic bases (adenine, cytosine, guanine, thymine and uracil), phosphoric acid, three amino acids (glycine, lysine, and L-histidine), D-glucose, alpha-D-glucose, tetrahydropyran (THP), 3-hydroxytetrahydrofuran and furan have been determined in the energy range 0.2-6.0 keV using a simple model based on the effective atomic total electron scattering cross sections (EATCS). The reliability of the model is confirmed by comparing the determined TCS with the predictions of those by existing theoretical models.

Theoretical and material studies of thin-film electroluminescent devices

NASA Technical Reports Server (NTRS)

Summers, C. J.

1989-01-01

Thin-film electroluminescent (TFEL) devices are studied for a possible means of achieving a high resolution, light weight, compact video display panel for computer terminals or television screens. The performance of TFEL devices depends upon the probability of an electron impact exciting a luminescent center which in turn depends upon the density of centers present in the semiconductor layer, the possibility of an electron achieving the impact excitation threshold energy, and the collision cross section itself. Efficiency of such a device is presently very poor. It can best be improved by increasing the number of hot electrons capable of impact exciting a center. Hot electron distributions and a method for increasing the efficiency and brightness of TFEL devices (with the additional advantage of low voltage direct current operation) are investigated.

Simulation of the 21 August 2017 Solar Eclipse Using the Whole Atmosphere Community Climate Model-eXtended

NASA Astrophysics Data System (ADS)

McInerney, Joseph M.; Marsh, Daniel R.; Liu, Han-Li; Solomon, Stanley C.; Conley, Andrew J.; Drob, Douglas P.

2018-05-01

We performed simulations of the atmosphere-ionosphere response to the solar eclipse of 21 August 2017 using the Whole Atmosphere Community Climate Model-eXtended (WACCM-X v. 2.0) with a fully interactive ionosphere and thermosphere. Eclipse simulations show temperature changes in the path of totality up to -3 K near the surface, -1 K at the stratopause, ±4 K in the mesosphere, and -40 K in the thermosphere. In the F region ionosphere, electron density is depleted by about 55%. Both the temperature and electron density exhibit global effects in the hours following the eclipse. There are also significant effects on stratosphere-mesosphere chemistry, including an increase in ozone by nearly a factor of 2 at 65 km. Dynamical impacts of the eclipse in the lower atmosphere appear to propagate to the upper atmosphere. This study provides insight into coupled eclipse effects through the entire atmosphere from the surface through the ionosphere.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darling, Christopher Lynn

By determining the production cross sections for heavy flavor hadrons, we test the theoretical predictions from perturhative quantum chroma-dynamics (QCD). In the case of pion induced beauty production, the few published results do not resolve the issue of the applicability of perturbative QCD. This analysis is undertaken in order to help resolve this situation. We determine the total beauty and charm production cross sections using an analysis of single electron decay products. We extract the cross sections per nucleon from the two-dimensional distribution of electron p versus impact parameter ( d) to the primary vertex. We place an upper limit on the beauty production cross section of σ bmore » $$\\bar{b}$$ < 105 nb at the 90% confidence level, where the limit includes both statistical and systematic errors. The charm production cross section is determined to be σ cc = 13.9$$+2.4/atop{-2.3}$$ (stat) ± 1.8 (syst) μ.b, which is in good agreement with next-to-leading order QCD predictions and other measurements.« less

The Global Statistical Response of the Outer Radiation Belt During Geomagnetic Storms

NASA Astrophysics Data System (ADS)

Murphy, K. R.; Watt, C. E. J.; Mann, I. R.; Jonathan Rae, I.; Sibeck, D. G.; Boyd, A. J.; Forsyth, C. F.; Turner, D. L.; Claudepierre, S. G.; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Blake, J. B.; Fennell, J.

2018-05-01

Using the total radiation belt electron content calculated from Van Allen Probe phase space density, the time-dependent and global response of the outer radiation belt during storms is statistically studied. Using phase space density reduces the impacts of adiabatic changes in the main phase, allowing a separation of adiabatic and nonadiabatic effects and revealing a clear modality and repeatable sequence of events in storm time radiation belt electron dynamics. This sequence exhibits an important first adiabatic invariant (μ)-dependent behavior in the seed (150 MeV/G), relativistic (1,000 MeV/G), and ultrarelativistic (4,000 MeV/G) populations. The outer radiation belt statistically shows an initial phase dominated by loss followed by a second phase of rapid acceleration, while the seed population shows little loss and immediate enhancement. The time sequence of the transition to the acceleration is also strongly μ dependent and occurs at low μ first, appearing to be repeatable from storm to storm.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raymund, T.D.

Recently, several tomographic techniques for ionospheric electron density imaging have been proposed. These techniques reconstruct a vertical slice image of electron density using total electron content data. The data are measured between a low orbit beacon satellite and fixed receivers located along the projected orbital path of the satellite. By using such tomographic techniques, it may be possible to inexpensively (relative to incoherent scatter techniques) image the ionospheric electron density in a vertical plane several times per day. The satellite and receiver geometry used to measure the total electron content data causes the data to be incomplete; that is, themore » measured data do not contain enough information to completely specify the ionospheric electron density distribution in the region between the satellite and the receivers. A new algorithm is proposed which allows the incorporation of other complementary measurements, such as those from ionosondes, and also includes ways to include a priori information about the unknown electron density distribution in the reconstruction process. The algorithm makes use of two-dimensional basis functions. Illustrative application of this algorithm is made to simulated cases with good results. The technique is also applied to real total electron content (TEC) records collected in Scandinavia in conjunction with the EISCAT incoherent scatter radar. The tomographic reconstructions are compared with the incoherent scatter electron density images of the same region of the ionosphere.« less

A Methodology to Assess the Impact of Optical and Electronic Crosstalk in a New Generation of Sensors Using Heritage Sensors

NASA Technical Reports Server (NTRS)

Oudrari, Hassan; Schwarting, Thomas; Chiang, Kwo-Fu; McIntire, Jeff; Pan, Chunhui; Xiong, Xiaoxiong; Butler, James

2010-01-01

Electronic and optical crosstalk are radiometric challenges that often exist in the focal plane design in many sensors Such as MODIS. A methodology is described to assess the impact due to optical and electronic crosstalk on the measured radiance, and thereafter, the retrieval of geophysical products using MODIS Level I data sets. Based on a postulated set of electronic and optical crosstalk coefficients, and a set of MODIS scenes, we have simulated a system signal contamination on any detector on a focal plane when another detector on that focal plane is stimulated with a geophysical signal. The original MODIS scenes and the crosstalk impacted scenes can be used with validated geophysical algorithms to derive the final data products. Products contaminated with crosstalk are then compared to those without contamination to assess the impact magnitude and location, and will allow us to separate Out-Of-Band (OOB) leaks from hand-to-hand optical crosstalk, and identify potential failures to meet climate research requirements.

A Web-based interactive diabetes registry for health care management and planning in Saudi Arabia.

PubMed

Al-Rubeaan, Khalid A; Youssef, Amira M; Subhani, Shazia N; Ahmad, Najlaa A; Al-Sharqawi, Ahmad H; Ibrahim, Heba M

2013-09-09

Worldwide, eHealth is a rapidly growing technology. It provides good quality health services at lower cost and increased availability. Diabetes has reached an epidemic stage in Saudi Arabia and has a medical and economic impact at a countrywide level. Data are greatly needed to better understand and plan to prevent and manage this medical problem. The Saudi National Diabetes Registry (SNDR) is an electronic medical file supported by clinical, investigational, and management data. It functions as a monitoring tool for medical, social, and cultural bases for primary and secondary prevention programs. Economic impact, in the form of direct or indirect cost, is part of the registry's scope. The registry's geographic information system (GIS) produces a variety of maps for diabetes and associated diseases. In addition to availability and distribution of health facilities in the Kingdom, GIS data provide health planners with the necessary information to make informed decisions. The electronic data bank serves as a research tool to help researchers for both prospective and retrospective studies. A Web-based interactive GIS system was designed to serve as an electronic medical file for diabetic patients retrieving data from medical files by trained registrars. Data was audited and cleaned before it was archived in the electronic filing system. It was then used to produce epidemiologic, economic, and geographic reports. A total of 84,942 patients were registered from 2000 to 2012, growing by 10% annually. The SNDR reporting system for epidemiology data gives better understanding of the disease pattern, types, and gender characteristics. Part of the reporting system is to assess quality of health care using different parameters, such as HbA1c, that gives an impression of good diabetes control for each institute. Economic reports give accurate cost estimation of different services given to diabetic patients, such as the annual insulin cost per patient for type 1, type 2, and gestational diabetes, which are 1155 SR (US $308), 1406 SR (US $375), and 1002 SR (US $267), respectively. Of this, 72.02% of the total insulin cost is spent on type 2 patients and 55.39% is in the form of premixed insulin. The SNDR can provide an accurate assessment of the services provided for research purposes. For example, only 27.00% of registered patients had an ophthalmic examination and only 71.10% of patients with proliferative retinopathy had laser therapy. The SNDR is an effective electronic medical file that can provide epidemiologic, economic, and geographic reports that can be used for disease management and health care planning. It is a useful tool for research and disease health care quality monitoring.

A Web-Based Interactive Diabetes Registry for Health Care Management and Planning in Saudi Arabia

PubMed Central

Youssef, Amira M; Subhani, Shazia N; Ahmad, Najlaa A; Al-Sharqawi, Ahmad H; Ibrahim, Heba M

2013-01-01

Background Worldwide, eHealth is a rapidly growing technology. It provides good quality health services at lower cost and increased availability. Diabetes has reached an epidemic stage in Saudi Arabia and has a medical and economic impact at a countrywide level. Data are greatly needed to better understand and plan to prevent and manage this medical problem. Objective The Saudi National Diabetes Registry (SNDR) is an electronic medical file supported by clinical, investigational, and management data. It functions as a monitoring tool for medical, social, and cultural bases for primary and secondary prevention programs. Economic impact, in the form of direct or indirect cost, is part of the registry’s scope. The registry’s geographic information system (GIS) produces a variety of maps for diabetes and associated diseases. In addition to availability and distribution of health facilities in the Kingdom, GIS data provide health planners with the necessary information to make informed decisions. The electronic data bank serves as a research tool to help researchers for both prospective and retrospective studies. Methods A Web-based interactive GIS system was designed to serve as an electronic medical file for diabetic patients retrieving data from medical files by trained registrars. Data was audited and cleaned before it was archived in the electronic filing system. It was then used to produce epidemiologic, economic, and geographic reports. A total of 84,942 patients were registered from 2000 to 2012, growing by 10% annually. Results The SNDR reporting system for epidemiology data gives better understanding of the disease pattern, types, and gender characteristics. Part of the reporting system is to assess quality of health care using different parameters, such as HbA1c, that gives an impression of good diabetes control for each institute. Economic reports give accurate cost estimation of different services given to diabetic patients, such as the annual insulin cost per patient for type 1, type 2, and gestational diabetes, which are 1155 SR (US $308), 1406 SR (US $375), and 1002 SR (US $267), respectively. Of this, 72.02% of the total insulin cost is spent on type 2 patients and 55.39% is in the form of premixed insulin. The SNDR can provide an accurate assessment of the services provided for research purposes. For example, only 27.00% of registered patients had an ophthalmic examination and only 71.10% of patients with proliferative retinopathy had laser therapy. Conclusions The SNDR is an effective electronic medical file that can provide epidemiologic, economic, and geographic reports that can be used for disease management and health care planning. It is a useful tool for research and disease health care quality monitoring. PMID:24025198

Total-dose radiation effects data for semiconductor devices, volume 2

NASA Technical Reports Server (NTRS)

Price, W. E.; Martin, K. E.; Nichols, D. K.; Gauthier, M. K.; Brown, S. F.

1981-01-01

Total ionizing dose radiation test data on integrated circuits are analyzed. Tests were performed with the electron accelerator (Dynamitron) that provides a steady state 2.5 MeV electron beam. Some radiation exposures were made with a Cobalt-60 gamma ray source. The results obtained with the Cobalt-60 source are considered an approximate measure of the radiation damage that would be incurred by an equivalent dose of electrons.

Compendium of Current Total Ionizing Dose and Displacement Damage Results from NASA GSFC and NEPP

NASA Technical Reports Server (NTRS)

Topper, Alyson D.; Campola, Michael J.; Chen, Dakai; Casey, Megan C.; Yau, Ka-Yen; Label, Kenneth A.; Cochran, Donna J.; O'Bryan, Martha V.

2017-01-01

Total ionizing dose and displacement damage testing was performed to characterize and determine the suitability of candidate electronics for NASA space utilization. Devices tested include opto-electronics, digital, analog, linear bipolar devices, and hybrid devices.

Ultraviolet Observations of Coronal Mass Ejection Impact on Comet 67P/Churyumov–Gerasimenko by Rosetta Alice

NASA Astrophysics Data System (ADS)

Noonan, John W.; Stern, S. Alan; Feldman, Paul D.; Broiles, Thomas; Wedlund, Cyril Simon; Edberg, Niklas J. T.; Schindhelm, Eric; Parker, Joel Wm.; Keeney, Brian A.; Vervack, Ronald J., Jr.; Steffl, Andrew J.; Knight, Matthew M.; Weaver, Harold A.; Feaga, Lori M.; A’Hearn, Michael; Bertaux, Jean-Loup

2018-07-01

The Alice ultraviolet spectrograph on the European Space Agency Rosetta spacecraft observed comet 67P/Churyumov–Gerasimenko in its orbit around the Sun for just over two years. Alice observations taken in 2015 October, two months after perihelion, show large increases in the comet’s Lyβ, O I 1304, O I 1356, and C I 1657 Å atomic emission that initially appeared to indicate gaseous outbursts. However, the Rosetta Plasma Consortium instruments showed a coronal mass ejection (CME) impact at the comet coincident with the emission increases, suggesting that the CME impact may have been the cause of the increased emission. The presence of the semi-forbidden O I 1356 Å emission multiplet is indicative of a substantial increase in dissociative electron impact emission from the coma, suggesting a change in the electron population during the CME impact. The increase in dissociative electron impact could be a result of the interaction between the CME and the coma of 67P or an outburst coincident with the arrival of the CME. The observed dissociative electron impact emission during this period is used to characterize the O2 content of the coma at two peaks during the CME arrival. The mechanism that could cause the relationship between the CME and UV emission brightness is not well constrained, but we present several hypotheses to explain the correlation.

Optical Measurements of Air Plasma

DTIC Science & Technology

2008-05-05

beam impact ionization of air was studied in the context of optical diagnostics . The electron beam originates in a pulsed 100 keV 20-mA source and...range of 636 Torr to 1 mTorr with pulse durations from 1 ms to 10 ms. Microwave diagnostics were used to quantify electron density and power; and an...optical diagnostic was used to quantify ozone production. An additional effort to quantify byproducts of electron impact ionization, that are

Modeling of Microplasmas with Nano-Engineered Electrodes

NASA Astrophysics Data System (ADS)

Macheret, Sergey; Tholeti, Siva Shashank; Alexeenko, Alina

2015-09-01

Microplasmas can potentially be used as unique tunable dielectrics for reconfigurable radio-frequency systems, if electron densities of 1010-1012 cm-3 can be sustained in cavities smaller than 100 micron. However, for low loss tangent, gas pressures below 10 mTorr would be required, whereas the physics of electron impact ionization dictates the pd scaling so that microplasmas must operate at high gas pressures, hundreds of Torr, and also high voltages. We analyze a new principle of plasma generation that goes well beyond the pd scaling by eliminating electron impact ionization. In the new concept, electrons are generated at the cathode by field emission from nanotubes, and ions are independently produced in field ionization at atomically-sharp tips on the anode. The electrons and ions then move in the opposite directions, mix, and create a plasma. The low pressure results in collisionless motion with no electron-impact ionization. One-dimensional PIC/MCC calculations show that emitters such as carbon nanotubes placed sparsely on the cathode, combined with field ionization nanorods at the anode, can indeed ensure steady-state electron densities of up to 1012 cm-3 at gas pressure lower than 10 mTorr with only 50-100 Volts applied cross a 40-50 μm gap.

Relativistic quantum mechanical calculations of electron-impact broadening for spectral lines in Be-like ions

NASA Astrophysics Data System (ADS)

Duan, B.; Bari, M. A.; Wu, Z. Q.; Jun, Y.; Li, Y. M.; Wang, J. G.

2012-11-01

Aims: We present relativistic quantum mechanical calculations of electron-impact broadening of the singlet and triplet transition 2s3s ← 2s3p in four Be-like ions from N IV to Ne VII. Methods: In our theoretical calculations, the K-matrix and related symmetry information determined by the colliding systems are generated by the DARC codes. Results: A careful comparison between our calculations and experimental results shows good agreement. Our calculated widths of spectral lines also agree with earlier theoretical results. Our investigations provide new methods of calculating electron-impact broadening parameters for plasma diagnostics.

Design of an ultra low power CMOS pixel sensor for a future neutron personal dosimeter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Y.; Hu-Guo, C.; Husson, D.

2011-07-01

Despite a continuously increasing demand, neutron electronic personal dosimeters (EPDs) are still far from being completely established because their development is a very difficult task. A low-noise, ultra low power consumption CMOS pixel sensor for a future neutron personal dosimeter has been implemented in a 0.35 {mu}m CMOS technology. The prototype is composed of a pixel array for detection of charged particles, and the readout electronics is integrated on the same substrate for signal processing. The excess electrons generated by an impinging particle are collected by the pixel array. The charge collection time and the efficiency are the crucial pointsmore » of a CMOS detector. The 3-D device simulations using the commercially available Synopsys-SENTAURUS package address the detailed charge collection process. Within a time of 1.9 {mu}s, about 59% electrons created by the impact particle are collected in a cluster of 4 x 4 pixels with the pixel pitch of 80 {mu}m. A charge sensitive preamplifier (CSA) and a shaper are employed in the frond-end readout. The tests with electrical signals indicate that our prototype with a total active area of 2.56 x 2.56 mm{sup 2} performs an equivalent noise charge (ENC) of less than 400 e - and 314 {mu}W power consumption, leading to a promising prototype. (authors)« less

Impact of distributed power electronics on the lifetime and reliability of PV systems: Impact of distributed power electronics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olalla, Carlos; Maksimovic, Dragan; Deline, Chris

Here, this paper quantifies the impact of distributed power electronics in photovoltaic (PV) systems in terms of end-of-life energy-capture performance and reliability. The analysis is based on simulations of PV installations over system lifetime at various degradation rates. It is shown how module-level or submodule-level power converters can mitigate variations in cell degradation over time, effectively increasing the system lifespan by 5-10 years compared with the nominal 25-year lifetime. An important aspect typically overlooked when characterizing such improvements is the reliability of distributed power electronics, as power converter failures may not only diminish energy yield improvements but also adversely affectmore » the overall system operation. Failure models are developed, and power electronics reliability is taken into account in this work, in order to provide a more comprehensive view of the opportunities and limitations offered by distributed power electronics in PV systems. Lastly, it is shown how a differential power-processing approach achieves the best mismatch mitigation performance and the least susceptibility to converter faults.« less

Impact of distributed power electronics on the lifetime and reliability of PV systems: Impact of distributed power electronics

DOE PAGES

Olalla, Carlos; Maksimovic, Dragan; Deline, Chris; ...

2017-04-26

Here, this paper quantifies the impact of distributed power electronics in photovoltaic (PV) systems in terms of end-of-life energy-capture performance and reliability. The analysis is based on simulations of PV installations over system lifetime at various degradation rates. It is shown how module-level or submodule-level power converters can mitigate variations in cell degradation over time, effectively increasing the system lifespan by 5-10 years compared with the nominal 25-year lifetime. An important aspect typically overlooked when characterizing such improvements is the reliability of distributed power electronics, as power converter failures may not only diminish energy yield improvements but also adversely affectmore » the overall system operation. Failure models are developed, and power electronics reliability is taken into account in this work, in order to provide a more comprehensive view of the opportunities and limitations offered by distributed power electronics in PV systems. Lastly, it is shown how a differential power-processing approach achieves the best mismatch mitigation performance and the least susceptibility to converter faults.« less

Determination of differential cross sections for electron-impact excitation of electronic states of molecular oxygen

NASA Astrophysics Data System (ADS)

Campbell, L.; Green, M. A.; Brunger, M. J.; Teubner, P. J.; Cartwright, D. C.

2000-02-01

The development and initial results of a method for the determination of differential cross sections for electron scattering by molecular oxygen are described. The method has been incorporated into an existing package of computer programs which, given spectroscopic factors, dissociation energies and an energy-loss spectrum for electron-impact excitation, determine the differential cross sections for each electronic state relative to that of the elastic peak. Enhancements of the original code were made to deal with particular aspects of electron scattering from O2, such as the overlap of vibrational levels of the ground state with transitions to excited states, and transitions to levels close to and above the dissocation energy in the Herzberg and Schumann-Runge continua. The utility of the code is specifically demonstrated for the ``6-eV states'' of O2, where we report absolute differential cross sections for their excitation by 15-eV electrons. In addition an integral cross section, derived from the differential cross section measurements, is also reported for this excitation process and compared against available theoretical results. The present differential and integral cross sections for excitation of the ``6-eV states'' of O2 are the first to be reported in the literature for electron-impact energies below 20 eV.

Search for weak M 1 transitions in 48Ca with inelastic proton scattering

NASA Astrophysics Data System (ADS)

Mathy, M.; Birkhan, J.; Matsubara, H.; von Neumann-Cosel, P.; Pietralla, N.; Ponomarev, V. Yu.; Richter, A.; Tamii, A.

2017-05-01

Background: The quenching of spin-isospin modes in nuclei is an important field of research in nuclear structure. It has an impact on astrophysical reaction rates and on fundamental processes like neutrinoless double-β decay. Gamow-Teller (GT) and spin-flip M 1 strengths are quenched. Concerning the latter, the Jπ=1+ resonance in the doubly magic nucleus 48Ca, dominated by a single transition, serves as a reference case. Purpose: The aim of the present work is to search for weak M 1 transitions in 48Ca with a high-resolution (p ,p') experiment at 295 MeV and forward angles including 0∘ and a comparison with results from a similar study using backward-angle electron scattering at low momentum transfers in order to estimate their contribution to the total B (M 1 ) strength in 48Ca. Methods: The spin-M 1 cross sections of individual peaks in the spectra are deduced with a multipole decomposition analysis (MDA) and converted to reduced spin-M 1 transition strengths by using the unit cross-section method. For a comparison with electron-scattering results, corresponding reduced B (M 1 ) transition strengths are extracted following the approach outlined in Birkhan et al. [Phys. Rev. C 93, 041302(R) (2016), 10.1103/PhysRevC.93.041302]. Results: In total, 30 peaks containing a M 1 contribution are found in the excitation energy region 7-13 MeV. The resulting B (M 1 ) strength distribution compares well to the electron-scattering results considering different factors limiting the sensitivity in both experiments and the enhanced importance of mechanisms breaking the proportionality of nuclear cross sections and electromagnetic matrix elements for weak transitions as studied here. The total strength of 1.14(7) μN2 deduced assuming a nonquenched isoscalar part of the (p ,p') cross sections agrees with the (e ,e') result of 1.21(13) μN2. A bin-wise analysis above 10 MeV provides an upper limit of 1.51(17) μN2. Conclusions: The present results confirm the previous electron-scattering work that weak transitions contribute about 25% to the total B (M 1 ) strength in 48Ca and the quenching factors of GT and spin-M 1 strength are then comparable in f p -shell nuclei. Thus, the role of meson-exchange currents seems to be negligible in 48Ca, in contrast to s d -shell nuclei.

Enhanced production of low energy electrons by alpha particle impact

PubMed Central

Kim, Hong-Keun; Titze, Jasmin; Schöffler, Markus; Trinter, Florian; Waitz, Markus; Voigtsberger, Jörg; Sann, Hendrik; Meckel, Moritz; Stuck, Christian; Lenz, Ute; Odenweller, Matthias; Neumann, Nadine; Schössler, Sven; Ullmann-Pfleger, Klaus; Ulrich, Birte; Fraga, Rui Costa; Petridis, Nikos; Metz, Daniel; Jung, Annika; Grisenti, Robert; Czasch, Achim; Jagutzki, Ottmar; Schmidt, Lothar; Jahnke, Till; Schmidt-Böcking, Horst; Dörner, Reinhard

2011-01-01

Radiation damage to living tissue stems not only from primary ionizing particles but to a substantial fraction from the dissociative attachment of secondary electrons with energies below the ionization threshold. We show that the emission yield of those low energy electrons increases dramatically in ion–atom collisions depending on whether or not the target atoms are isolated or embedded in an environment. Only when the atom that has been ionized and excited by the primary particle impact is in immediate proximity of another atom is a fragmentation route known as interatomic Coulombic decay (ICD) enabled. This leads to the emission of a low energy electron. Over the past decade ICD was explored in several experiments following photoionization. Most recent results show its observation even in water clusters. Here we show the quantitative role of ICD for the production of low energy electrons by ion impact, thus approaching a scenario closer to that of radiation damage by alpha particles: We choose ion energies on the maximum of the Bragg peak where energy is most efficiently deposited in tissue. We compare the electron production after colliding He+ ions on isolated Ne atoms and on Ne dimers (Ne2). In the latter case the Ne atom impacted is surrounded by a most simple environment already opening ICD as a deexcitation channel. As a consequence, we find a dramatically enhanced low energy electron yield. The results suggest that ICD may have a significant influence on cell survival after exposure to ionizing radiation. PMID:21730184

Atomic electron energies including relativistic effects and quantum electrodynamic corrections

NASA Technical Reports Server (NTRS)

Aoyagi, M.; Chen, M. H.; Crasemann, B.; Huang, K. N.; Mark, H.

1977-01-01

Atomic electron energies have been calculated relativistically. Hartree-Fock-Slater wave functions served as zeroth-order eigenfunctions to compute the expectation of the total Hamiltonian. A first order correction to the local approximation was thus included. Quantum-electrodynamic corrections were made. For all orbitals in all atoms with 2 less than or equal to Z less than or equal to 106, the following quantities are listed: total energies, electron kinetic energies, electron-nucleus potential energies, electron-electron potential energies consisting of electrostatic and Breit interaction (magnetic and retardation) terms, and vacuum polarization energies. These results will serve for detailed comparison of calculations based on other approaches. The magnitude of quantum electrodynamic corrections is exhibited quantitatively for each state.

Resistive anode image converter

NASA Technical Reports Server (NTRS)

Lampton, M. L.; Paresce, F. (Inventor)

1976-01-01

The invention of an apparatus for imaging soft X-ray and ultraviolet electromagnetic radiation and charged particles was described. The apparatus includes a pair of microchannel electron multiplier plates connected in a cascaded chevron configuration which intercepts an incident beam of radiation or charged particles. Incident photons or charged particles strike the front surface of the chevron configuration causing emission of electrons. The electrons are accelerated by a voltage gradient and strike the inner side walls of the individual channels, causing emission of secondary electrons. Accelerated and multiplied secondary electrons impinge upon a resistive anode after they transverse the chevron configuration. A pulse position circuit converts the magnitude or transit time of the currents flowing from the point of impact of the electrons on the resistive anode to four contact electrodes mounted on their periphery of the resistive anode into the spatial coordinates of electron impact.

Metastable Oxygen Production by Electron-Impact of Oxygen

NASA Astrophysics Data System (ADS)

Hein, J. D.; Malone, C. P.; Johnson, P. V.; Kanik, I.

2014-12-01

Electron-impact excitation processes involving atomic and molecular oxygen are important in atmospheric interactions. The production of long-lived metastable O(1S) and O(1D) through electron impact of oxygen-containing molecules plays a significant role in the dynamics of planetary atmospheres (Earth, Mars, Europa, Io, Enceladus) and cometary bodies (Hale-Bopp). The electron-impact excitation channels to O(1S) and O(1D) are important for determining energy partitioning and dynamics. To reliably model natural phenomena and interpret observational data, the accurate determination of underlying collision processes (cross sections, dissociation dynamics) through fundamental experimental studies is essential. The detection of metastable species in laboratory experiments requires a novel approach. Typical radiative de-excitation detection techniques cannot be performed due to the long-lived nature of excited species, and conventional particle detectors are insensitive to the low internal energies O(1S) and O(1D). We have recently constructed an apparatus to detect and characterize metastable oxygen production by electron impact using the "rare gas conversion technique." Recent results will be presented, including absolute excitation functions for target gases O2, CO, CO2, and N2O. This work was performed at the Jet Propulsion Laboratory (JPL), California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA). Financial support through NASA's OPR, PATM, and MFRP programs, as well as the NASA Postdoctoral Program (NPP) are gratefully acknowledged.

Electron Impact Studies Relevant to Rosetta Coma Measurements of 67P/Churyumov-Gerasimenko

NASA Astrophysics Data System (ADS)

Bodewits, D.; Feldman, P. D.; Matejčík, Š.; Országh, J.; Durian, M.

2017-12-01

Auroral emission from electron impact processes can provide a remote window on the physical properties of plasma and neutral gases surrounding small bodies (Galand & Chakrabarti, 2002; Roth et al. 2014). Surprisingly, Rosetta found that outside 2 AU pre-perihelion, atomic and molecular emission features in the inner coma were predominantly caused by dissociative electron impact excitation (Feldman et al. 2015). When the comet came within 2 au of the Sun, fluorescent emission became the dominant process, as water densities in the inner coma could effectively cool the electron population below the appearance energy of the relevant electron impact dissociative excitation processes (Bodewits et al. 2016). Further quantitative interpretation of the Alice and OSIRIS images of the coma is by limited excitation cross sections measured of electron impact reactions with the gases present in cometary comae, including H2O, CO2, CO, O2, and HCN. We will present the first results of a series of experiments dedicated to investigate the emission features seen by the instruments on board Rosetta. The experimental set up is located at the Comenius University in Bratislava, Slovakia, and consists of a crossed-beam configuration combining an electron monochromator and a gas beam (Danko et al. 2013). The electron induced emission spectra are measured using a Czerny-Turner optical monochromator provides a spectral resolution of 0.3 nm FWHM and is equipped with a photomultiplier sensitive between 185 and 710 nm. References: Bodewits, D. et al. The Astronomical Journal 152, 130 (2016). Danko, M. et al. J. Phys. B 46, 045203 (2013). Feldman, P. D. et al. Astron. Astroph. 583, A8 (2015). Galand, M. & Chakrabarti, S. Geophysical Monograph 130. Ed. Michael Mendillo 130, 55- (2002). Roth, L., Saur, J., Retherford, K. D., Strobel, D. F. & Feldman, P. D. Science (2014). doi:10.1126/science.1247051

The impact of electron beam irradiation on Low density polyethylene and Ethylene vinyl acetate

NASA Astrophysics Data System (ADS)

Sabet, Maziyar; Soleimani, Hassan

2017-05-01

Improvement of measured gel content, hardness, tensile strength and elongation at break of Ethylene vinyl acetate (EVA) have confirmed positive effect of electron beam irradiation on EVA. Results obtained from both gel content tests show that degree of cross-linking in amorphous regions is dependent on dose. A significant improvement in tensile strength of neat EVA samples is obtained upon electron-beam radiation up to 210 kGy. Similarly, hardness properties of Low-density polyethylene (LDPE) improvewith increasing electron beam irradiation. This article deals with the impacts of electron beam (EB) irradiation on the properties of LDPE and Ethylene-Vinyl Acetate (EVA) as the two common based formulations for wire and cable applications.

Influence of electron correlation on the cross section and linear polarization of radiation emitted by electron-impact excitation of Ca+ and Ba+ ions

NASA Astrophysics Data System (ADS)

Chen, Zhan-Bin

2018-04-01

Calculations of the electron-impact excitation (EIE) of singly charged Ca+ and Ba+ ions and subsequent de-excitation process are performed using a fully relativistic distorted wave (RDW) method. To resolve the discrepancy between previous theory and experiment, careful consideration is given to the generation of the target state wave-functions through the systematic inclusion of electron correlations. It is found that the electron correlation effects play a significant role on the cross section, while the effects on the linear polarization of the emitted radiation are relatively small. Good agreement between our result and experiment is obtained.

Automated Risk Assessment for Stroke in Atrial Fibrillation (AURAS-AF)--an automated software system to promote anticoagulation and reduce stroke risk: study protocol for a cluster randomised controlled trial.

PubMed

Holt, Tim A; Fitzmaurice, David A; Marshall, Tom; Fay, Matthew; Qureshi, Nadeem; Dalton, Andrew R H; Hobbs, F D Richard; Lasserson, Daniel S; Kearley, Karen; Hislop, Jenny; Jin, Jing

2013-11-13

Patients with atrial fibrillation (AF) are at significantly increased risk of stroke. Oral anticoagulants (OACs) substantially reduce this risk, with gains seen across the spectrum of baseline risk. Despite the benefit to patients, OAC prescribing remains suboptimal in the United Kingdom (UK). We will investigate whether an automated software system, operating within primary care electronic medical records, can improve the management of AF by identifying patients eligible for OAC therapy and increasing uptake of this treatment. We will conduct a cluster randomised controlled trial, involving general practices using the Egton Medical Information Systems (EMIS) Web clinical system. We will randomise practices to use an electronic software tool or to continue with usual care. The tool will a) produce (and continually refresh) a list of patients with AF who are eligible for OAC therapy--practices will invite these patients to discuss therapy at the start of the trial--and b) generate electronic screen reminders in the medical records of those eligible, appearing throughout the trial. The software will run for 6 months in 23 intervention practices. A total of 23 control practices will manage their AF register in line with the usual care offered. The primary outcome is change in proportion of eligible patients with AF who have been prescribed OAC therapy after six months. Secondary outcomes are incidence of stroke, transient ischaemic attack, other major thromboembolism, major haemorrhage and reports of inappropriate OAC prescribing in the data collection sample--those deemed eligible for OACs. We will conduct a process evaluation in parallel with the randomised trial. We will use qualitative methods to examine patient and practitioner views of the intervention and its impact on primary care practice, including its time implications. AURAS-AF will investigate whether a simple intervention, using electronic primary care records, can improve OAC uptake in a high risk group for stroke. Given previous concerns about safety, especially surrounding inappropriate prescribing, we will also examine whether electronic reminders safely impact care in this clinical area. http://ISRCTN 55722437.

Electron impact study of potassium hydroxide

NASA Technical Reports Server (NTRS)

Vuskovic, L.; Trajmar, S.

1979-01-01

An attempt is made to measure the sum of the elastic, rotational and vibrational scattering of electrons by KOH at low impact energies (5 to 20 eV) at angles from 10 to 120 deg. Energy loss spectra taken in the 0 to 18 eV range using an electron impact spectrometer are used to identify the species contributing to electric scattering. At temperatures between 300 and 500 C, only inelastic spectral features belonging to water are detected, while at temperatures from 500 to 800 C strong atomic K lines, indicative of molecular dissociation, and H2 energy loss features become prominent. No features attributable to KOH, the KOH dimer, O2 or potassium oxides were observed, due to the effects of the dissociation products, and it is concluded that another technique will have to be developed in order to measure electron scattering by KOH.

Dissociative excitation of vacuum ultraviolet emission features by electron impact on molecular gases. 3: CO2

NASA Technical Reports Server (NTRS)

Mumma, M. J.; Borst, W. L.; Zipf, E. C.

1972-01-01

Vacuum ultraviolet multiplets of C I, C II, and O I were produced by electron impact of CO2. Absolute emission cross sections for these multiplets were measured from threshold to 350 eV. The electrostatically focussed electron gun used in this series of experiments is described in detail. The atomic multiplets which were produced by dissociative excitation of CO2 and the cross sections at 100 eV are given. The dependence of the excitation functions on electron energy shows that these multiplets are produced by electric-dipole-allowed transitions in CO2.

Single charge exchange between hydrogen-like projectiles and hydrogen atom: the post version of the BDW-4B approximation

NASA Astrophysics Data System (ADS)

Azizan, Sh; Shojaei, F.; Fathi, R.

2016-04-01

The post version of the four-body Born distorted wave method (BDW-4B) is applied to calculate the total cross section for single electron exchange in the collision of hydrogen-like projectiles with hydrogen atom. The post form of transition amplitude is obtained in terms of two-dimensional real integrals which can be computed numerically. This second-order theory which satisfies the correct boundary conditions is used for the collision of {{H}}, {{H}}{{{e}}}+, {{L}}{{{i}}}2+, {{{B}}}4+, {{{C}}}5+ with hydrogen atoms at intermediate and high impact energies. The validity of our results is assessed in comparison with available experimental data and other theories.

Study of ionospheric anomalies due to impact of typhoon using Principal Component Analysis and image processing

NASA Astrophysics Data System (ADS)

LIN, JYH-WOEI

2012-08-01

Principal Component Analysis (PCA) and image processing are used to determine Total Electron Content (TEC) anomalies in the F-layer of the ionosphere relating to Typhoon Nakri for 29 May, 2008 (UTC). PCA and image processing are applied to the global ionospheric map (GIM) with transforms conducted for the time period 12:00-14:00 UT on 29 May, 2008 when the wind was most intense. Results show that at a height of approximately 150-200 km the TEC anomaly is highly localized; however, it becomes more intense and widespread with height. Potential causes of these results are discussed with emphasis given to acoustic gravity waves caused by wind force.

Development of SiC Large Tapered Crystal Growth

NASA Technical Reports Server (NTRS)

Neudeck, Phil

2011-01-01

Research Focus Area: Power Electronics, Temperature Tolerant Devices. Demonstrate initial feasibility of totally new "Large Tapered Crystal" (LTC) process for growing vastly improved large-diameter wide-band gap wafers. Addresses Targets: The goal of this research is to experimentally investigate and demonstrate feasibility of the key unproven LTC growth processes in SiC. Laser-assisted growth of long SiC fiber seeds. Radial epitaxial growth enlargement of seeds into large SiC boules. Uniqueness and Impacts open a new technology path to large-diameter SiC and GaN wafers with 1000-fold defect density improvement at 2-4 fold lower cost. Leapfrog improvement in wide band gap power device capability and cost.

Towards autonomous environmental monitoring systems.

PubMed

Sequeira, Margaret; Bowden, Michaela; Minogue, Edel; Diamond, Dermot

2002-02-11

The concept of micro total analysis systems (muTAS) or Lab-on-a-chip is based on the twin strategies of integration and miniaturisation that have been so successful in the electronics industry. This paper will look at the materials issues, particularly with respect to the new polymeric materials that are becoming available, and strategies for integrating optical (colorimetric) detection. The influence of breakthroughs in apparently unrelated areas on the range of chemistries that can be applied will be illustrated. For environmental monitoring, the further integration of wireless communications with micro-dimensioned analytical instruments and sensors will become the ultimate driving force. The emergence of these compact, self-sustaining, networked instruments will have enormous impact on all field-based environmental measurements.

Double differential cross sections for proton induced electron emission from molecular analogues of DNA constituents for energies in the Bragg peak region

NASA Astrophysics Data System (ADS)

Rudek, Benedikt; Bennett, Daniel; Bug, Marion U.; Wang, Mingjie; Baek, Woon Yong; Buhr, Ticia; Hilgers, Gerhard; Champion, Christophe; Rabus, Hans

2016-09-01

For track structure simulations in the Bragg peak region, measured electron emission cross sections of DNA constituents are required as input for developing parameterized model functions representing the scattering probabilities. In the present work, double differential cross sections were measured for the electron emission from vapor-phase pyrimidine, tetrahydrofuran, and trimethyl phosphate that are structural analogues to the base, the sugar, and the phosphate residue of the DNA, respectively. The range of proton energies was from 75 keV to 135 keV, the angles ranged from 15° to 135°, and the electron energies were measured from 10 eV to 200 eV. Single differential and total electron emission cross sections are derived by integration over angle and electron energy and compared to the semi-empirical Hansen-Kocbach-Stolterfoht (HKS) model and a quantum mechanical calculation employing the first Born approximation with corrected boundary conditions (CB1). The CB1 provides the best prediction of double and single differential cross section, while total cross sections can be fitted with semi-empirical models. The cross sections of the three samples are proportional to their total number of valence electrons.

Strong interference effects in the resonant Auger decay of atoms induced by intense x-ray fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demekhin, Philipp V.; Cederbaum, Lorenz S.

2011-02-15

The theory of resonant Auger decay of atoms in a high-intensity coherent x-ray pulse is presented. The theory includes the coupling between the ground state and the resonance due to an intense x-ray pulse, taking into account the decay of the resonance and the direct photoionization of the ground state, both populating the final ionic states coherently. The theory also considers the impact of the direct photoionization of the resonance state itself which typically populates highly excited ionic states. The combined action of the resonant decay and of the direct ionization of the ground state in the field induces amore » non-Hermitian time-dependent coupling between the ground and the ''dressed'' resonance stats. The impact of these competing processes on the total electron yield and on the 2s{sup 2}2p{sup 4}({sup 1}D)3p {sup 2}P spectator and 2s{sup 1}2p{sup 6} {sup 2}S participator Auger decay spectra of the Ne 1s{yields}3p resonance is investigated. The role of the direct photoionization of the ground state and of the resonance increases dramatically with the field intensity. This results in strong interference effects with distinct patterns in the electron spectra, which differ for the participator and spectator final states.« less

Molecular Data for a Biochemical Model of DNA Radiation Damage: Electron Impact Ionization and Dissociative Ionization of DNA Bases and Sugar-Phosphate Backbone

NASA Technical Reports Server (NTRS)

Dateo, Christopher E.; Fletcher, Graham D.

2004-01-01

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 C3'- and C5'-deoxyribose-phospate, 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 C3'- and C5'-deoxyribose-phospate cross sections, differing by less than 10%. 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-Hl)(+), with the cytosine ion losing H at the 1 position, is also reported. The threshold of this process is calculated to be 17.1 eV. Detailed analysis of ionization products such as in DI is important to trace the sequential steps in the biochemical process of DNA damage.

The New Publishing: Technology's Impact on the Publishing Industry over the Next Decade.

ERIC Educational Resources Information Center

Rawlins, Gregory J. E.

1992-01-01

Discusses technology's impact on the products, revenue sources, and distribution channels of the publishing industry over the next decade. Highlights include electronic books and copy protection; copyright; advantages of electronic books to users, libraries, and publishers; retailing schemes; changes in education; subscription publishing;…

Methods and apparatus for cooling electronics

DOEpatents

Hall, Shawn Anthony; Kopcsay, Gerard Vincent

2014-12-02

Methods and apparatus are provided for choosing an energy-efficient coolant temperature for electronics by considering the temperature dependence of the electronics' power dissipation. This dependence is explicitly considered in selecting the coolant temperature T.sub.0 that is sent to the equipment. To minimize power consumption P.sub.Total for the entire system, where P.sub.Total=P.sub.0+P.sub.Cool is the sum of the electronic equipment's power consumption P.sub.0 plus the cooling equipment's power consumption P.sub.Cool, P.sub.Total is obtained experimentally, by measuring P.sub.0 and P.sub.Cool, as a function of three parameters: coolant temperature T.sub.0; weather-related temperature T.sub.3 that affects the performance of free-cooling equipment; and computational state C of the electronic equipment, which affects the temperature dependence of its power consumption. This experiment provides, for each possible combination of T.sub.3 and C, the value T.sub.0* of T.sub.0 that minimizes P.sub.Total. During operation, for any combination of T.sub.3 and C that occurs, the corresponding optimal coolant temperature T.sub.0* is selected, and the cooling equipment is commanded to produce it.

Wearable glass beads for in vivo dosimetry of total skin electron irradiation treatments

NASA Astrophysics Data System (ADS)

Nabankema, S. K.; Jafari, S. M.; Peet, S. C.; Binny, D.; Sylvander, S. R.; Crowe, S. B.

2017-11-01

Glass beads have recently been proposed for use as radiation therapy dosimeters. Glass beads have a number of characteristics that make them suitable for in vivo skin dose measurements, including an ability to be worn on a string, and therefore avoid possible patient discomfort that may result from the use of adhesives. In this study, their use for in vivo dose measurements in total skin electron irradiation treatments has been tested. First, the dosimetric properties of cylindrical beads with a 3 mm diameter were characterised using electron fields produced by a linear accelerator. The mean individual bead reproducibility was demonstrated to be within 3%; and a batch variation of 7% was observed. The beads were shown to have a linear dose response, and both dose rate and beam energy independence, within the measurement uncertainty. Phantom measurements were then performed for a total skin electron irradiation beam arrangement, and results compared against optically stimulated luminescent dosimeters at five anatomical sites. For a majority of measurement locations, agreement within 3% was observed between the two dosimetry techniques, demonstrating the feasibility of glass beads as in vivo dosimeters for total skin electron irradiation; though further investigation may be needed to minimise uncertainty in results.

Patching the Exchange-Correlation Potential in Density Functional Theory.

PubMed

Huang, Chen

2016-05-10

A method for directly patching exchange-correlation (XC) potentials in materials is derived. The electron density of a system is partitioned into subsystem densities by dividing its Kohn-Sham (KS) potential among the subsystems. Inside each subsystem, its projected KS potential is required to become the total system's KS potential. This requirement, together with the nearsightedness principle of electronic matters, ensures that the electronic structures inside subsystems can be good approximations to the total system's electronic structure. The nearsightedness principle also ensures that subsystem densities could be well localized in their regions, making it possible to use high-level methods to invert the XC potentials for subsystem densities. Two XC patching methods are developed. In the local XC patching method, the total system's XC potential is improved in the cluster region. We show that the coupling between a cluster and its environment is important for achieving a fast convergence of the electronic structure in the cluster region. In the global XC patching method, we discuss how to patch the subsystem XC potentials to construct the XC potential in the total system, aiming to scale up high-level quantum mechanics simulations of materials. Proof-of-principle examples are given.

Fast method for in-flight estimation of total dose from protons and electrons using RADE Minstrument on JUICE

NASA Astrophysics Data System (ADS)

Hajdas, Wojtek; Mrigakshi, Alankrita; Xiao, Hualin

2017-04-01

The primary concern of the ESA JUICE mission to Jupiter is the harsh particle radiation environment. Ionizing particles introduce radiation damage by total dose effects, displacement damages or single events effects. Therefore, both the total ionizing dose and the displacement damage equivalent fluence must be assessed to alert spacecraft and its payload as well as to quantify radiation levels for the entire mission lifetime. We present a concept and implementations steps for simplified method used to compute in flight a dose rate and total dose caused by protons. We also provide refinement of the method previously developed for electrons. The dose rates values are given for predefined active volumes located behind layers of materials with known thickness. Both methods are based on the electron and proton flux measurements provided by the Electron and Proton Detectors inside the Radiation Hard Electron Monitor (RADEM) located on-board of JUICE. The trade-off between method accuracy and programming limitations for in-flight computations are discussed. More comprehensive and precise dose rate computations based on detailed analysis of all stack detectors will be made during off-line data processing. It will utilize full spectral unfolding from all RADEM detector subsystems.

On the role of electron-driven processes in planetary atmospheres and comets

NASA Astrophysics Data System (ADS)

Campbell, L.; Brunger, M. J.

2009-11-01

After the presence of ionized layers in the Earth's atmosphere was inferred, it took 50 years to quantitatively understand them. The electron density could not be accounted for until Sir David Bates first suggested (along with Sir Harrie Massey) that the main electron-loss process was dissociative recombination with molecular ions, and he and colleagues then developed a theory to predict those rates of dissociative recombination. However, electron impact processes, particularly excitation, have been considered insignificant in most situations, in both planetary and cometary atmospheres. Here we describe cases where recent calculations have shown that electron impact excitation of molecules is important, suggesting that, just as in the time of Sir David Bates, electron-driven processes remain fundamental to our quantitative understanding of atmospheric and cometary phenomena.

Modeling electron beam parameters and plasma interface position in an anode plasma electron gun with hydrogen atmosphere

NASA Astrophysics Data System (ADS)

Krauze, A.; Virbulis, J.; Kravtsov, A.

2018-05-01

A beam glow discharge based electron gun can be applied as heater for silicon crystal growth systems in which silicon rods are pulled from melt. Impacts of high-energy charged particles cause wear and tear of the gun and generate an additional source of silicon contamination. A steady-state model for electron beam formation has been developed to model the electron gun and optimize its design. Description of the model and first simulation results are presented. It has been shown that the model can simulate dimensions of particle impact areas on the cathode and anode, but further improvements of the model are needed to correctly simulate electron trajectory distribution in the beam and the beam current dependence on the applied gas pressure.

Thermoluminescent dosimetry in electron beams: energy dependence.

PubMed

Robar, V; Zankowski, C; Olivares Pla, M; Podgorsak, E B

1996-05-01

The response of thermoluminescent dosimeters to electron irradiations depends on the radiation dose, mean electron energy at the position of the dosimeter in phantom, and the size of the dosimeter. In this paper the semi-empirical expression proposed by Holt et al. [Phys. Med. Biol. 20, 559-570 (1975)] is combined with the calculated electron dose fraction to determine the thermoluminescent dosimetry (TLD) response as a function of the mean electron energy and the dosimeter size. The electron and photon dose fractions, defined as the relative contributions of electrons and bremsstrahlung photons to the total dose for a clinical electron beam, are calculated with Monte Carlo techniques using EGS4. Agreement between the calculated and measured TLD response is very good. We show that the considerable reduction in TLD response per unit dose at low electron energies, i.e., at large depths in phantom, is offset by an ever-increasing relative contribution of bremsstrahlung photons to the total dose of clinical electron beams. This renders the TLD sufficiently reliable for dose measurements over the entire electron depth dose distribution despite the dependence of the TLD response on electron beam energy.

NASA STI Program Seminar: Electronic documents

NASA Technical Reports Server (NTRS)

1994-01-01

The theme of this NASA Scientific and Technical Information Program Seminar was electronic documents. Topics covered included Electronic Documents Management at the CASI, the Impact of Electronic Publishing on User Expectations and Searching Image Record Management, Secondary Publisher Considerations for Electronic Journal Literature, and the Technical Manual Publishing On Demand System (TMPODS).

Scanning electron microscope/energy dispersive x ray analysis of impact residues in LDEF tray clamps

NASA Technical Reports Server (NTRS)

Bernhard, Ronald P.; Durin, Christian; Zolensky, Michael E.

1993-01-01

Detailed optical scanning of tray clamps is being conducted in the Facility for the Optical Inspection of Large Surfaces at JSC to locate and document impacts as small as 40 microns in diameter. Residues from selected impacts are then being characterized by Scanning Electron Microscopy/Energy Dispersive X-ray Analysis at CNES. Results from this analysis will be the initial step to classifying projectile residues into specific sources.

The Electronic Thermal Conductivity of Graphene.

PubMed

Kim, Tae Yun; Park, Cheol-Hwan; Marzari, Nicola

2016-04-13

Graphene, as a semimetal with the largest known thermal conductivity, is an ideal system to study the interplay between electronic and lattice contributions to thermal transport. While the total electrical and thermal conductivity have been extensively investigated, a detailed first-principles study of its electronic thermal conductivity is still missing. Here, we first characterize the electron-phonon intrinsic contribution to the electronic thermal resistivity of graphene as a function of doping using electronic and phonon dispersions and electron-phonon couplings calculated from first-principles at the level of density-functional theory and many-body perturbation theory (GW). Then, we include extrinsic electron-impurity scattering using low-temperature experimental estimates. Under these conditions, we find that the in-plane electronic thermal conductivity κe of doped graphene is ∼300 W/mK at room temperature, independently of doping. This result is much larger than expected and comparable to the total thermal conductivity of typical metals, contributing ∼10% to the total thermal conductivity of bulk graphene. Notably, in samples whose physical or domain sizes are of the order of few micrometers or smaller, the relative contribution coming from the electronic thermal conductivity is more important than in the bulk limit, because lattice thermal conductivity is much more sensitive to sample or grain size at these scales. Last, when electron-impurity scattering effects are included we find that the electronic thermal conductivity is reduced by 30 to 70%. We also find that the Wiedemann-Franz law is broadly satisfied at low and high temperatures but with the largest deviations of 20-50% around room temperature.

Electronic Ordering System Improves Postoperative Pain Management After Total Knee or Hip Arthroplasty

PubMed Central

Chiu, T.; Wolfe, S.; Magid, S.

2015-01-01

Summary Objectives The authors investigated the impact of computerized provider order entry (CPOE) on the delivery times of analgesia and subsequent patient outcomes. We hypothesized that patients would report less pain and use less pain medications compared with the previous paper-based system. Methods Two groups of patients after a total hip (THA) or knee arthroplasty (TKA) were retrospectively compared: one comprising 106 patients when the paper-based ordering system was in effect (conventional group), and one comprising 96 patients after CPOE was installed (electronic group). All patients received a regional anaesthetic at surgery (combined spinal-epidural). TKA patients also received a single-injection femoral nerve block. After transfer to the postoperative anaesthesia care unit (PACU), a patient-controlled epidural analgesia (PCEA) infusion was initiated. The following data was collected from the PACU record: time to initiation of analgesia, visual analog scale (VAS) pain scores at initiation of analgesia and hourly for the first postoperative day (POD), volume of pain medication used, length of stay (LOS) in the PACU and the hospital. Results The time to initiation of analgesia from arrival in the PACU was significantly lower in the electronic group compared to the conventional group (24.5 ± 28.3 minutes vs. 51.1 ± 26.2 minutes; mean ± SD, p < 0.001), as were VAS pain scores (0.82 ± 1.08 vs. 1.5 ± 1.52, p < 0.001) and the volume of PCEA needed to control pain (27.9 ± 20.2 ml vs. 34.8 ± 20.3 ml, p = 0.001) at 4 hours postoperatively. PACU LOS and hospital LOS did not significantly differ in the two groups. Conclusions After implementation of CPOE, patients received their postoperative analgesia faster, had less pain, and required less medication. PMID:26448800

[Card-based age control mechanisms at tobacco vending machines. Effect and consequences].

PubMed

Schneider, S; Meyer, C; Löber, S; Röhrig, S; Solle, D

2010-02-01

Until recently, 700,000 tobacco vending machines provided uncontrolled access to cigarettes for children and adolescents in Germany. On January 1, 2007, a card-based electronic locking device was attached to all tobacco vending machines to prevent the purchase of cigarettes by children and adolescents under 16. Starting in 2009, only persons older than 18 are able to buy cigarettes from tobacco vending machines. The aim of the present investigation (SToP Study: "Sources of Tobacco for Pupils" Study) was to assess changes in the number of tobacco vending machines after the introduction of these new technical devices (supplier's reaction). In addition, the ways smoking adolescents make purchases were assessed (consumer's reaction). We registered and mapped the total number of tobacco points of sale (tobacco POS) before and after the introduction of the card-based electronic locking device in two selected districts of the city of Cologne. Furthermore, pupils from local schools (response rate: 83%) were asked about their tobacco consumption and ways of purchase using a questionnaire. Results indicated that in the area investigated the total number of tobacco POSs decreased from 315 in 2005 to 277 in 2007. The rates of decrease were 48% for outdoor vending machines and 8% for indoor vending machines. Adolescents reported circumventing the card-based electronic locking devices (e.g., by using cards from older friends) and using other tobacco POSs (especially newspaper kiosks) or relying on their social network (mainly friends). The decreasing number of tobacco vending machines has not had a significant impact on cigarette acquisition by adolescent smokers as they tend to circumvent the newly introduced security measures.

A practical theoretical formalism for atomic multielectron processes: direct multiple ionization by a single auger decay or by impact of a single electron or photon

NASA Astrophysics Data System (ADS)

Liu, Pengfei; Zeng, Jiaolong; Yuan, Jianmin

2018-04-01

Multiple electron processes occur widely in atoms, molecules, clusters, and condensed matters when they are interacting with energetic particles or intense laser fields. Direct multielectron processes (DMEP) are the most complicated among the general multiple electron processes and are the most difficult to describe theoretically. In this work, a unified and accurate theoretical formalism is proposed on the DMEP of atoms including the multiple auger decay and multiple ionization by an impact of a single electron or a single photon based on the atomic collision theory described by a correlated many-body Green's function. Such a practical treatment is made possible by taking consideration of the different coherence features of the atoms (matter waves) in the initial and final states. We first explain how the coherence characteristics of the ejected continuum electrons is largely destructed, by taking the electron impact direct double ionization process as an example. The direct double ionization process is completely different from the single ionization where the complete interference can be maintained. The detailed expressions are obtained for the energy correlations among the continuum electrons and energy resolved differential and integral cross sections according to the separation of knock-out (KO) and shake-off (SO) mechanisms for the electron impact direct double ionization, direct double and triple auger decay, and double and triple photoionization (TPI) processes. Extension to higher order DMEP than triple ionization is straight forward by adding contributions of the following KO and SO processes. The approach is applied to investigate the electron impact double ionization processes of C+, N+, and O+, the direct double and triple auger decay of the K-shell excited states of C+ 1s2{s}22{p}2{}2D and {}2P, and the double and TPI of lithium. Comparisons with the experimental and other theoretical investigations wherever available in the literature show that our theoretical formalism is accurate and effective in treating the atomic multielectron processes.

Rocket measurements of conjugate photoelectrons during the total solar eclipse of 7 March 1970 over Wallops Island.

NASA Technical Reports Server (NTRS)

Maier, E. J.; Narasinga Rao, B. C.

1972-01-01

Results of measurements made with a retarding potential analyzer on a Nike-Tomahawk rocket during the totality of the solar eclipse, showing definite evidence for the existence of photoelectrons from the conjugate hemisphere. Photoelectrons are observed in the altitude range from 120 to 260 km. The observed flux in the energy range from 2 to 30 eV is relatively constant above about 200 km, but decreased below that altitude. The flux of 5-eV energy electrons above 200 km altitude is about 10 to the 7th power electrons/cm/sec/eV. Higher-energy electrons were also observed, and it is possible that the energy content of these observed fluxes of conjugate-point photoelectrons is sufficient to maintain the observed electron densities and temperatures during the total eclipse.

On the role of electronic friction for dissociative adsorption and scattering of hydrogen molecules at a Ru(0001) surface.

PubMed

Füchsel, Gernot; Schimka, Selina; Saalfrank, Peter

2013-09-12

The role of electronic friction and, more generally, of nonadiabatic effects during dynamical processes at the gas/metal surface interface is still a matter of discussion. In particular, it is not clear if electronic nonadiabaticity has an effect under "mild" conditions, when molecules in low rovibrational states interact with a metal surface. In this paper, we investigate the role of electronic friction on the dissociative sticking and (inelastic) scattering of vibrationally and rotationally cold H2 molecules at a Ru(0001) surface theoretically. For this purpose, classical molecular dynamics with electronic friction (MDEF) calculations are performed and compared to MD simulations without friction. The two H atoms move on a six-dimensional potential energy surface generated from gradient-corrected density functional theory (DFT), that is, all molecular degrees of freedom are accounted for. Electronic friction is included via atomic friction coefficients obtained from an embedded atom, free electron gas (FEG) model, with embedding densities taken from gradient-corrected DFT. We find that within this model, dissociative sticking probabilities as a function of impact kinetic energies and impact angles are hardly affected by nonadiabatic effects. If one accounts for a possibly enhanced electronic friction near the dissociation barrier, on the other hand, reduced sticking probabilities are observed, in particular, at high impact energies. Further, there is always an influence on inelastic scattering, in particular, as far as the translational and internal energy distribution of the reflected molecules is concerned. Additionally, our results shed light on the role played by the velocity distribution of the incident molecular beam for adsorption probabilities, where, in particular, at higher impact energies, large effects are found.

Confidence Level Based Approach to Total Dose Specification for Spacecraft Electronics

NASA Technical Reports Server (NTRS)

Xapsos, M. A.; Stauffer, C.; Phan, A.; McClure, S. S.; Ladbury, R. L.; Pellish, J. A.; Campola, M. J.; Label, K. A.

2017-01-01

A confidence level based approach to total dose radiation hardness assurance is presented for spacecraft electronics. It is applicable to both ionizing and displacement damage dose. Results are compared to the traditional approach that uses radiation design margin and advantages of the new approach are discussed.

Compendium of Current Total Ionizing Dose and Displacement Damage Results from NASA Goddard Space Flight Center and Selected NASA Electronic Parts and Packaging Program

NASA Technical Reports Server (NTRS)

Topper, Alyson D.; Campola, Michael J.; Chen, Dakai; Casey, Megan C.; Yau, Ka-Yen; Cochran, Donna J.; LaBel, Kenneth A.; Ladbury, Raymond L.; Lauenstein, Jean-Marie; Mondy, Timothy K.;

Current Total Ionizing Dose Results and Displacement Damage Results for Candidate Spacecraft Electronics for NASA

NASA Technical Reports Server (NTRS)

Cochran, Donna J.; Kniffin, Scott D.; LaBel, Kenneth A.; OBryan, Martha V.; Reed, Robert A.; Ladbury, Ray L.; Howard, James W., Jr.; Poivey, Christian; Buchner, Stephen P.; Marshall, Cheryl J.

2004-01-01

We present data on the vulnerability of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage. Devices tested include optoelectronics, digital, analog, linear bipolar devices, hybrid devices, Analog-to-Digital Converters (ADCs), and Digital-to-Analog Converters (DACS), among others.

Total Ionizing Dose Results and Displacement Damage Results for Candidate Spacecraft Electronics for NASA

NASA Technical Reports Server (NTRS)

Cochran, Donna J.; Kniffin, Scott D.; LaBel, Kenneth A.; OBryan, Martha V.; Reed, Robert A.; Ladbury, Ray L.; Howard, James W., Jr.; Poivey, Christian; Buchner, Stephen P.; Marshall, Cheryl J.

2003-01-01

We present data on the vulnerability of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage. Devices tested include optoelectronics, digital, analog, linear bipolar devices, hybrid devices, Analog-to-Digital Converters (ADCs), and Digital-to-Analog Converters (DACs), among others.

Variations of total electron content during geomagnetic disturbances: A model/observation comparison

NASA Technical Reports Server (NTRS)

Roble, G. Lu X. Pi A. D. Richmond R. G.

1997-01-01

This paper studies the ionospheric response to major geomagnetic storm of October 18-19, 1995, using the thermosphere-ionosphere electrodynamic general circulation model (TIE-GCM) simulations and the global ionospheric maps (GIM) of total electron content (TEC) observations from the Global Positioning System (GPS) worldwide network.

Validation of the electronic version of the BREAST-Q in the army of women study.

PubMed

Fuzesi, Sarah; Cano, Stefan J; Klassen, Anne F; Atisha, Dunya; Pusic, Andrea L

2017-06-01

Women undergoing surgery for primary breast cancer can choose between breast conserving therapy and mastectomy (with or without breast reconstruction). Patients often turn to outcomes data to help guide the decision-making process. The BREAST-Q is a validated breast surgery-specific patient-reported outcome measure that evaluates satisfaction, quality of life, and patient experience. It was originally developed for paper-and-pencil administration. However, the BREAST-Q has increasingly been administered electronically. Therefore, the aim of this study was to evaluate the psychometric properties of an electronic version of the BREAST-Q in a large online survey. Women with a history of breast cancer surgery recruited from the Love/AVON Army of Women program completed an electronic version of the BREAST-Q in addition to the Impact of Cancer Survey and PTSD Checklist. Traditional psychometric analyses were performed on the collected data. BREAST-Q data were collected from 6748 women (3497 Breast Conserving Therapy module, 1295 Mastectomy module, 1956 Breast Reconstruction module). Acceptability was supported by a high response rate (82%), low frequency of missing data (<5%), and maximum endorsement frequencies (<80%) in all but 17 items. Scale reliability was supported by high Cronbach's α coefficients (≥0.78) and item-total correlations (range of means, 0.65-0.91). Validity was supported by interscale correlations, convergent and divergent hypotheses as well as clinical hypotheses. The electronically administered BREAST-Q yields highly reliable, clinically meaningful data for use in clinical outcomes research. The BREAST-Q can be used in the clinical setting, whether administered electronically or using paper-and-pencil, at the choice of the patient and surgeon. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combined photon-electron beams in the treatment of the supraclavicular lymph nodes in breast cancer: A novel technique that achieves adequate coverage while reducing lung dose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salem, Ahmed, E-mail: ahmed.salem@doctors.org.uk; Mohamad, Issa; Dayyat, Abdulmajeed

2015-10-01

Radiation pneumonitis is a well-documented side effect of radiation therapy for breast cancer. The purpose of this study was to compare combined photon-electron, photon-only, and electron-only plans in the radiation treatment of the supraclavicular lymph nodes. In total, 13 patients requiring chest wall and supraclavicular nodal irradiation were planned retrospectively using combined photon-electron, photon-only, and electron-only supraclavicular beams. A dose of 50 Gy over 25 fractions was prescribed. Chest wall irradiation parameters were fixed for all plans. The goal of this planning effort was to cover 95% of the supraclavicular clinical target volume (CTV) with 95% of the prescribed dosemore » and to minimize the volume receiving ≥ 105% of the dose. Comparative end points were supraclavicular CTV coverage (volume covered by the 95% isodose line), hotspot volume, maximum radiation dose, contralateral breast dose, mean total lung dose, total lung volume percentage receiving at least 20 Gy (V{sub 20} {sub Gy}), heart volume percentage receiving at least 25 Gy (V{sub 25} {sub Gy}). Electron and photon energies ranged from 8 to 18 MeV and 4 to 6 MV, respectively. The ratio of photon-to-electron fractions in combined beams ranged from 5:20 to 15:10. Supraclavicular nodal coverage was highest in photon-only (mean = 96.2 ± 3.5%) followed closely by combined photon-electron (mean = 94.2 ± 2.5%) and lowest in electron-only plans (mean = 81.7 ± 14.8%, p < 0.001). The volume of tissue receiving ≥ 105% of the prescription dose was higher in the electron-only (mean = 69.7 ± 56.1 cm{sup 3}) as opposed to combined photon-electron (mean = 50.8 ± 40.9 cm{sup 3}) and photon-only beams (mean = 32.2 ± 28.1 cm{sup 3}, p = 0.114). Heart V{sub 25} {sub Gy} was not statistically different among the plans (p = 0.999). Total lung V{sub 20} {sub Gy} was lowest in electron-only (mean = 10.9 ± 2.3%) followed by combined photon-electron (mean = 13.8 ± 2.3%) and highest in photon-only plans (mean = 16.2 ± 3%, p < 0.001). As expected, photon-only plans demonstrated the highest target coverage and total lung V{sub 20} {sub Gy}. The superiority of electron-only beams, in terms of decreasing lung dose, is set back by the dosimetric hotspots associated with such plans. Combined photon-electron treatment is a feasible technique for supraclavicular nodal irradiation and results in adequate target coverage, acceptable dosimetric hotspot volume, and slightly reduced lung dose.« less

Study of the Effects of the Electric Field on Charging Measurements on Individual Micron-size Dust Grains by Secondary Electron Emissions

NASA Technical Reports Server (NTRS)

Tankosic, D.; Abbas, M. M.

2013-01-01

The dust charging by electron impact is an important dust charging process in Astrophysical, Planetary, and the Lunar environments. Low energy electrons are reflected or stick to the grains charging the dust grains negatively. At sufficiently high energies electrons penetrate the grain leading to excitation and emission of electrons referred to as secondary electron emission (SEE). Available theoretical models for the calculation of SEE yield applicable for neutral, planar or bulk surfaces are generally based on Sternglass Equation. However, viable models for charging of individual dust grains do not exist at the present time. Therefore, the SEE yields have to be obtained by some experimental methods at the present time. We have conducted experimental studies on charging of individual micron size dust grains in simulated space environments using an electrodynamic balance (EDB) facility at NASA-MSFC. The results of our extensive laboratory study of charging of individual micron-size dust grains by low energy electron impact indicate that the SEE by electron impact is a very complex process expected to be substantially different from the bulk materials. It was found that the incident electrons may lead to positive or negative charging of dust grains depending upon the grain size, surface potential, electron energy, electron flux, grain composition, and configuration. In this paper we give a more elaborate discussion about the possible effects of the AC field in the EDB on dust charging measurements by comparing the secondary electron emission time-period (tau (sub em) (s/e)) with the time-period (tau (sub ac) (ms)) of the AC field cycle in the EDB that we have briefly addressed in our previous publication.

The Impact of Technology on High School Principals

ERIC Educational Resources Information Center

Hines, Christopher; Edmonson, Stacey; Moore, George W.

2008-01-01

The purpose of this study was (a) to research the impact of electronic communication on the role of the principal and school leaders and (b) to investigate patterns of unanticipated consequences or phenomena that have developed within the organization along with the widespread use of electronic media. Twelve themes were identified and grouped into…

Impact of Knowledge Resources Linked to an Electronic Health Record on Frequency of Unnecessary Tests and Treatments

ERIC Educational Resources Information Center

Goodman, Kenneth; Grad, Roland; Pluye, Pierre; Nowacki, Amy; Hickner, John

2012-01-01

Introduction: Electronic knowledge resources have the potential to rapidly provide answers to clinicians' questions. We sought to determine clinicians' reasons for searching these resources, the rate of finding relevant information, and the perceived clinical impact of the information they retrieved. Methods: We asked general internists, family…

Electron impact excitation coefficients for laboratory and astrophysical plasmas

NASA Technical Reports Server (NTRS)

Davis, J.; Kepple, P. C.; Blaha, M.

1976-01-01

Electron impact excitation rate coefficients have been obtained for a number of transitions in highly ionized ions of interest to astrophysical and laboratory plasmas. The calculations were done using the method of distorted waves. Results are presented for various transitions in highly ionized Ne, Na, Al, Si, A, Ca, Ni and Fe.

Challenges in Optical Emission Spectroscopy

NASA Astrophysics Data System (ADS)

Siepa, Sarah; Berger, Birk; Schulze, Julian; Schuengel, Edmund; von Keudell, Achim

2016-09-01

Collisional-radiative models (CRMs) are widely used to investigate plasma properties such as electron density, electron temperature and the form of the electron energy distribution function. In this work an extensive CRM for argon is presented, which models 30 excited states and various kinds of processes including electron impact excitation/de-excitation, radiation and radiation trapping. The CRM is evaluated in several test cases, i.e. inductively and capacitively coupled plasmas at various pressures, powers/voltages and gas admixtures. Deviations are found between modelled and measured spectra. The escape factor as a means of describing radiation trapping is discussed as well as the cross section data for electron impact processes. This work was supported by the Ruhr University Research School PLUS, funded by Germany's Excellence Initiative [DFG GSC 98/3].

Electron impact ionization of O2 and the interference effect from forward-backward asymmetry

NASA Astrophysics Data System (ADS)

Chowdhury, Madhusree Roy; Tribedi, Lokesh C.

2017-08-01

Absolute double differential cross sections (DDCSs) of secondary electrons emitted from O2 under the impact of 7 keV electrons were measured for different emission angles between 30° and 145° having energies from 1-600 eV. The forward-backward angular asymmetry was observed from angular distribution of the DDCS of secondary electrons. The asymmetry parameter, thus obtained from the DDCS of two complementary angles, showed a clear signature of interference oscillation. The Cohen-Fano model of Young type electron interference at a molecular double slit is found to provide a good fit to the observed oscillatory structures. The present observation is in qualitative agreement with the recent results obtained from photoionization.

Transmission Electron Microscopy of Cometary Residues from Micron-Sized Craters in the Stardust Al-Foils

NASA Technical Reports Server (NTRS)

Leroux, Hugues; Stroud, Rhonda M.; Dai, Zu Rong; Graham, Giles A.; Troadec, David; Bradley, John P.; Teslich, Nick; Borg, Janet; Kearsley, Anton T.; Horz, Friedrich

2008-01-01

We report Transmission Electron Microscopy (TEM) investigations of micro-craters that originated from hypervelocity impacts of comet 81P/Wild 2 dust particles on the aluminium foil of the Stardust collector. The craters were selected by Scanning Electron Microscopy (SEM) and then prepared by Focused Ion Beam (FIB) milling techniques in order to provide electron transparent cross-sections for TEM studies. The crater residues contain both amorphous and crystalline materials in varying proportions and compositions. The amorphous component is interpreted as resulting from shock melting during the impact and the crystalline phases as relict minerals. The latter show evidence for shock metamorphism. Based on the residue morphology and the compositional variation, the impacting particles are inferred to have been dominated by mixtures of submicron olivine, pyroxene and Fe-sulfide grains, in agreement with prior results of relatively coarse-grained mineral assemblages in the aerogel collector.

On the importance of electron impact processes in excimer-pumped alkali laser-induced plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Markosyan, Aram H.

We present that the excimer-pumped alkali laser (XPAL) system has recently been demonstrated in several different mixtures of alkali vapor and rare gas. Without special preventive measures, plasma formation during operation of XPAL is unavoidable. Some recent advancements in the availability of reliable data for electron impact collisions with atoms and molecules have enabled development of a complete reaction mechanism to investigate XPAL-induced plasmas. Here, we report on pathways leading to plasma formation in an Ar/C 2H 6/CsAr/C2H6/Cs XPAL sustained at different cell temperatures. We find that depending on the operating conditions, the contribution of electron impact processes can bemore » as little as bringing the excitation of Cs(P 2) states to higher level Cs** states, and can be as high as bringing Cs(P 2) excited states to a full ionization. Increasing the input pumping power or cell temperature, or decreasing the C 2H 6 mole fraction leads to electron impact processes dominating in plasma formation over the energy pooling mechanisms previously reported in literature.« less

Following electron impact excitation of single (N, O, F, Ne, Na, Mg, Al, Si) atom L subshells ionization cross section calculations by using Lotz's equation

NASA Astrophysics Data System (ADS)

Aydinol, Mahmut

2017-02-01

L shell and L subshells ionization cross sections σL and σLi (i = 1, 2, 3) following electron impact on (N,O, F, Ne, Na, Mg, Al, Si) atoms calculated. By using Lotz' equation for nonrelativistic cases in Matlab σL and σLi cross section values obtained for ten electron impact(Eo) values in the range of ELi

On the importance of electron impact processes in excimer-pumped alkali laser-induced plasmas

DOE PAGES

Markosyan, Aram H.

2017-10-18

We present that the excimer-pumped alkali laser (XPAL) system has recently been demonstrated in several different mixtures of alkali vapor and rare gas. Without special preventive measures, plasma formation during operation of XPAL is unavoidable. Some recent advancements in the availability of reliable data for electron impact collisions with atoms and molecules have enabled development of a complete reaction mechanism to investigate XPAL-induced plasmas. Here, we report on pathways leading to plasma formation in an Ar/C 2H 6/CsAr/C2H6/Cs XPAL sustained at different cell temperatures. We find that depending on the operating conditions, the contribution of electron impact processes can bemore » as little as bringing the excitation of Cs(P 2) states to higher level Cs** states, and can be as high as bringing Cs(P 2) excited states to a full ionization. Increasing the input pumping power or cell temperature, or decreasing the C 2H 6 mole fraction leads to electron impact processes dominating in plasma formation over the energy pooling mechanisms previously reported in literature.« less

Non-resonant multipactor--A statistical model

NASA Astrophysics Data System (ADS)

Rasch, J.; Johansson, J. F.

2012-12-01

High power microwave systems operating in vacuum or near vacuum run the risk of multipactor breakdown. In order to avoid multipactor, it is necessary to make theoretical predictions of critical parameter combinations. These treatments are generally based on the assumption of electrons moving in resonance with the electric field while traversing the gap between critical surfaces. Through comparison with experiments, it has been found that only for small system dimensions will the resonant approach give correct predictions. Apparently, the resonance is destroyed due to the statistical spread in electron emission velocity, and for a more valid description it is necessary to resort to rather complicated statistical treatments of the electron population, and extensive simulations. However, in the limit where resonance is completely destroyed it is possible to use a much simpler treatment, here called non-resonant theory. In this paper, we develop the formalism for this theory, use it to calculate universal curves for the existence of multipactor, and compare with previous results. Two important effects that leads to an increase in the multipactor threshold in comparison with the resonant prediction are identified. These are the statistical spread of impact speed, which leads to a lower average electron impact speed, and the impact of electrons in phase regions where the secondary electrons are immediately reabsorbed, leading to an effective removal of electrons from the discharge.

Collision cross sections of N2 by H+ impact at keV energies within time-dependent density-functional theory

NASA Astrophysics Data System (ADS)

Yu, W.; Gao, C.-Z.; Zhang, Y.; Zhang, F. S.; Hutton, R.; Zou, Y.; Wei, B.

2018-03-01

We calculate electron capture and ionization cross sections of N2 impacted by the H+ projectile at keV energies. To this end, we employ the time-dependent density-functional theory coupled nonadiabatically to molecular dynamics. To avoid the explicit treatment of the complex density matrix in the calculation of cross sections, we propose an approximate method based on the assumption of constant ionization rate over the period of the projectile passing the absorbing boundary. Our results agree reasonably well with experimental data and semi-empirical results within the measurement uncertainties in the considered energy range. The discrepancies are mainly attributed to the inadequate description of exchange-correlation functional and the crude approximation for constant ionization rate. Although the present approach does not predict the experiments quantitatively for collision energies below 10 keV, it is still helpful to calculate total cross sections of ion-molecule collisions within a certain energy range.

A real-time ionospheric model based on GNSS Precise Point Positioning

NASA Astrophysics Data System (ADS)

Tu, Rui; Zhang, Hongping; Ge, Maorong; Huang, Guanwen

2013-09-01

This paper proposes a method of real-time monitoring and modeling the ionospheric Total Electron Content (TEC) by Precise Point Positioning (PPP). Firstly, the ionospheric TEC and receiver’s Differential Code Biases (DCB) are estimated with the undifferenced raw observation in real-time, then the ionospheric TEC model is established based on the Single Layer Model (SLM) assumption and the recovered ionospheric TEC. In this study, phase observations with high precision are directly used instead of phase smoothed code observations. In addition, the DCB estimation is separated from the establishment of the ionospheric model which will limit the impacts of the SLM assumption impacts. The ionospheric model is established at every epoch for real time application. The method is validated with three different GNSS networks on a local, regional, and global basis. The results show that the method is feasible and effective, the real-time ionosphere and DCB results are very consistent with the IGS final products, with a bias of 1-2 TECU and 0.4 ns respectively.

Microstructural Study of Micron-Sized Craters Simulating Stardust Impacts in Aluminum 1100 Targets

NASA Technical Reports Server (NTRS)

Leroux, Hugues; Borg, Janet; Troadec, David; Djouadi, Zahia; Horz, Friedrich

2006-01-01

Various microscopic techniques were used to characterize experimental micro- craters in aluminium foils to prepare for the comprehensive analysis of the cometary and interstellar particle impacts in aluminium foils to be returned by the Stardust mission. First, SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) were used to study the morphology of the impact craters and the bulk composition of the residues left by soda-lime glass impactors. A more detailed structural and compositional study of impactor remnants was then performed using TEM (Transmission Electron Microscopy), EDS, and electron diffraction methods. The TEM samples were prepared by Focused Ion Beam (FIB) methods. This technique proved to be especially valuable in studying impact crater residues and impact crater morphology. Finally, we also showed that InfraRed microscopy (IR) can be a quick and reliable tool for such investigations. The combination of all of these tools enables a complete microscopic characterization of the craters.

Image Sharing Technologies and Reduction of Imaging Utilization: A Systematic Review and Meta-analysis.

PubMed

Vest, Joshua R; Jung, Hye-Young; Ostrovsky, Aaron; Das, Lala Tanmoy; McGinty, Geraldine B

2015-12-01

Image sharing technologies may reduce unneeded imaging by improving provider access to imaging information. A systematic review and meta-analysis were conducted to summarize the impact of image sharing technologies on patient imaging utilization. Quantitative evaluations of the effects of PACS, regional image exchange networks, interoperable electronic heath records, tools for importing physical media, and health information exchange systems on utilization were identified through a systematic review of the published and gray English-language literature (2004-2014). Outcomes, standard effect sizes (ESs), settings, technology, populations, and risk of bias were abstracted from each study. The impact of image sharing technologies was summarized with random-effects meta-analysis and meta-regression models. A total of 17 articles were included in the review, with a total of 42 different studies. Image sharing technology was associated with a significant decrease in repeat imaging (pooled effect size [ES] = -0.17; 95% confidence interval [CI] = [-0.25, -0.09]; P < .001). However, image sharing technology was associated with a significant increase in any imaging utilization (pooled ES = 0.20; 95% CI = [0.07, 0.32]; P = .002). For all outcomes combined, image sharing technology was not associated with utilization. Most studies were at risk for bias. Image sharing technology was associated with reductions in repeat and unnecessary imaging, in both the overall literature and the most-rigorous studies. Stronger evidence is needed to further explore the role of specific technologies and their potential impact on various modalities, patient populations, and settings. Copyright © 2015 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Image Sharing Technologies and Reduction of Imaging Utilization: A Systematic Review and Meta-analysis

PubMed Central

Vest, Joshua R.; Jung, Hye-Young; Ostrovsky, Aaron; Das, Lala Tanmoy; McGinty, Geraldine B.

2016-01-01

Introduction Image sharing technologies may reduce unneeded imaging by improving provider access to imaging information. A systematic review and meta-analysis were conducted to summarize the impact of image sharing technologies on patient imaging utilization. Methods Quantitative evaluations of the effects of PACS, regional image exchange networks, interoperable electronic heath records, tools for importing physical media, and health information exchange systems on utilization were identified through a systematic review of the published and gray English-language literature (2004–2014). Outcomes, standard effect sizes (ESs), settings, technology, populations, and risk of bias were abstracted from each study. The impact of image sharing technologies was summarized with random-effects meta-analysis and meta-regression models. Results A total of 17 articles were included in the review, with a total of 42 different studies. Image sharing technology was associated with a significant decrease in repeat imaging (pooled effect size [ES] = −0.17; 95% confidence interval [CI] = [−0.25, −0.09]; P < .001). However, image sharing technology was associated with a significant increase in any imaging utilization (pooled ES = 0.20; 95% CI = [0.07, 0.32]; P = .002). For all outcomes combined, image sharing technology was not associated with utilization. Most studies were at risk for bias. Conclusions Image sharing technology was associated with reductions in repeat and unnecessary imaging, in both the overall literature and the most-rigorous studies. Stronger evidence is needed to further explore the role of specific technologies and their potential impact on various modalities, patient populations, and settings. PMID:26614882

Pore-water chemistry from the ICDP-USGS coer hole in the Chesapeake Bay impact structure--Implications for paleohydrology, microbial habitat, and water resources

USGS Publications Warehouse

Sanford, Ward E.; Voytek, Mary A.; Powars, David S.; Jones, Blair F.; Cozzarelli, Isabelle M.; Eganhouse, Robert P.; Cockell, Charles S.

2009-01-01

We investigated the groundwater system of the Chesapeake Bay impact structure by analyzing the pore-water chemistry in cores taken from a 1766-m-deep drill hole 10 km north of Cape Charles, Virginia. Pore water was extracted using high-speed centrifuges from over 100 cores sampled from a 1300 m section of the drill hole. The pore-water samples were analyzed for major cations and anions, stable isotopes of water and sulfate, dissolved and total carbon, and bioavailable iron. The results reveal a broad transition between fresh and saline water from 100 to 500 m depth in the post-impact sediment section, and an underlying syn-impact section that is almost entirely filled with brine. The presence of brine in the lowermost post-impact section and the trend in the dissolved chloride with depth suggest a transport process dominated by molecular diffusion and slow, compaction-driven, upward flow. Major ion results indicate residual effects of diagenesis from heating, and a pre-impact origin for the brine. High levels of dissolved organic carbon (6-95 mg/L) and the distribution of electron acceptors indicate an environment that may be favorable for microbial activity throughout the drilled section. The concentration and extent of the brine is much greater than had previously been observed, suggesting its occurrence may be common in the inner crater. However, groundwater flow conditions in the structure may reduce the salt-water-intrusion hazard associated with the brine.

Neutral-atom electron binding energies from relaxed-orbital relativistic Hartree-Fock-Slater calculations for Z between 2 and 106

NASA Technical Reports Server (NTRS)

Huang, K.-N.; Aoyagi, M.; Mark, H.; Chen, M. H.; Crasemann, B.

1976-01-01

Electron binding energies in neutral atoms have been calculated relativistically, with the requirement of complete relaxation. Hartree-Fock-Slater wave functions served as zeroth-order eigenfunctions to compute the expectation of the total Hamiltonian. A first-order correction to the local approximation was thus included. Quantum-electrodynamic corrections were made. For all elements with atomic numbers ranging from 2 to 106, the following quantities are listed: total energies, electron kinetic energies, electron-nucleus potential energies, electron-electron potential energies consisting of electrostatic and Breit interaction (magnetic and retardation) terms, and vacuum polarization energies. Binding energies including relaxation are listed for all electrons in all atoms over the indicated range of atomic numbers. A self-energy correction is included for the 1s, 2s, and 2p(1/2) levels. Results for selected atoms are compared with energies calculated by other methods and with experimental values.

Use of Total Electron Content data to analyze ionosphere electron density gradients

NASA Astrophysics Data System (ADS)

Nava, B.; Radicella, S. M.; Leitinger, R.; Coisson, P.

In presence of electron density gradients the thin shell approximation for the ionosphere used together with a simple mapping function to convert slant Total Electron Content TEC to vertical TEC could lead to TEC conversion errors Therefore these mapping function errors can be used to identify the effects of the electron density gradients in the ionosphere In the present work high precision GPS derived slant TEC data have been used to investigate the effects of the electron density gradients in the middle and low latitude ionosphere under geomagnetic quiet and disturbed conditions In particular the data corresponding to the geographic area of the American sector for the days 5-7 April 2000 have been used to perform a complete analysis of mapping function errors based on the coinciding pierce point technique The results clearly illustrate the electron density gradient effects according to the locations considered and to the actual levels of disturbance of the ionosphere

Comparative study of X-ray emission from plasma focus relative to different preionization schemes

NASA Astrophysics Data System (ADS)

Ahmad, S.; Qayyum, A.; Hassan, M.; Zakaullah, M.

2017-07-01

A 2.7-kJ Mather-type plasma focus has been investigated for X-ray emission with preionization produced by an α-source, a β-source, and a shunt resistor. Time-resolved and time integrated measurements are carried out using a PIN-diode-based X-ray spectrometer and pinhole camera. The β-source (28Ni63) assisted preionization enhances the X-ray emission up to 25%, while preionization induced by depleted uranium (92U238) increases both Cu-Kα and total X-ray yield of about 100%. The preionization caused by the optimum shunt resistor enhances the Cu-Kα and total X-ray yield of about 53%. It is found that preionization also broadens the working pressure range for the high X-ray yield and improves the shot-to-shot reproducibility of the system. Pinhole images reveal that the X-ray emission from the anode tip is dominant owing to impact of electron bombardment, while the X-ray emission from hot spots is also visible.

Reconstruction of the ionospheric electron density by geostatistical inversion

NASA Astrophysics Data System (ADS)

Minkwitz, David; van den Boogaart, Karl Gerald; Hoque, Mainul; Gerzen, Tatjana

2015-04-01

The ionosphere is the upper part of the atmosphere where sufficient free electrons exist to affect the propagation of radio waves. Typically, the ionosphere extends from about 50 - 1000 km and its morphology is mainly driven by solar radiation, particle precipitation and charge exchange. Due to the strong ionospheric impact on many applications dealing with trans-ionospheric signals such as Global Navigation Satellite Systems (GNSS) positioning, navigation and remote sensing, the demand for a highly accurate reconstruction of the electron density is ever increasing. Within the Helmholtz Alliance project "Remote Sensing and Earth System Dynamics" (EDA) the utilization of the upcoming radar mission TanDEM-L and its related products are prepared. The TanDEM-L mission will operate in L-band with a wavelength of approximately 24 cm and aims at an improved understanding of environmental processes and ecosystem change, e.g. earthquakes, volcanos, glaciers, soil moisture and carbon cycle. Since its lower frequency compared to the X-band (3 cm) and C-band (5 cm) radar missions, the influence of the ionosphere will increase and might lead to a significant degradation of the radar image quality if no correction is applied. Consequently, our interest is the reconstruction of the ionospheric electron density in order to mitigate the ionospheric delay. Following the ionosphere's behaviour we establish a non-stationary and anisotropic spatial covariance model of the electron density separated into a vertical and horizontal component. In order to estimate the model's parameters we chose a maximum likelihood approach. This approach incorporates GNSS total electron content measurements, representing integral measurements of the electron density between satellite to receiver ray paths, and the NeQuick model as a non-stationary trend. Based on a multivariate normal distribution the spatial covariance model parameters are optimized and afterwards the 3D electron density can be calculated by kriging for arbitrary points or grids of interest.

Electronic management: Exploring its impact on small business

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bewayo, E.D.

Macworld magazine recently reported that more than one in five companies eavesdrops electronically on its employees. Electronic eavesdropping is one name given to electronic management Besides being known as electronic eaves-dropping, electronic management also goes by electronic monitoring, electronic supervision, electronic snooping, electronic sweat-shopping, electronic surveillance, electronic Big Brothering, and computerized performance monitoring. Some of these labels connote negative things about electronic management, and relate to applications of electronic management to extreme and unreasonable levels. In the rest of this paper the terms electronic management and electronic monitoring will be used interchangeably. In this paper we discuss the impacts ofmore » electronic management, positive and negative, on workplaces, with emphasis on small businesses. This small business emphasis is partly because of the author`s research interests, and partly because most of what has been written on electronic management has been based on large business contexts. This large business bias has been partly due to the fact that the early inroads of electronic management were almost exclusively limited to large companies--beginning with telephone service observation in the late 1800s. However, now with the growing affordability and, consequently, the proliferation of electronic technology (especially the computer), electronic management is no longer the monopoly of large corporations. Electronic management has now reached restaurants, drug stores, liquor stores, convenience stores, and trucking companies. And in some industries, e.g., banking, every business, regardless of size, uses electronic monitoring.« less

Electron impact excitation of tin

NASA Astrophysics Data System (ADS)

Sharma, Lalita; Bharti, Swati; Srivastava, Rajesh

2017-05-01

We study the electron impact excitation of the fine-structure levels of the ground state configuration 5p2 to the excited states of the configuration 5p6s in tin atom. These calculations have been carried out in the jj coupling scheme using the relativistic distorted-wave method. Results for differential cross section are reported at incident electron energies 20, 50, 80 and 100 eV while integrated cross sections are presented in the incident electron energy range of 5 to 100 eV. Contribution to the Topical Issue: "Low-Energy Interactions related to Atmospheric and Extreme Conditions", edited by S. Ptasinska, M. Smialek-Telega, A. Milosavljevic and B. Sivaraman.

Observation of fast and slow interatomic Coulombic decay in argon dimers induced by electron-impact ionization

NASA Astrophysics Data System (ADS)

Ren, Xueguang; Miteva, Tsveta; Kolorenč, Přemysl; Gokhberg, Kirill; Kuleff, Alexander I.; Cederbaum, Lorenz S.; Dorn, Alexander

2017-09-01

We investigate the interatomic Coulombic decay (ICD) in argon dimers induced by electron-impact ionization (E0=90 eV ) using a multiparticle coincidence experiment in which the momentum vectors and, consequently, the kinetic energies for electrons and fragment ions are determined. The signature of the ICD process is obtained from a correlation map between ejected electron energy and kinetic energy release (KER) for Ar++Ar+ fragment ions where low-energy ICD electrons can be identified. Furthermore, two types of ICD processes, termed fast and slow interatomic decay, are separated by the ICD initial-state energies and projectile energy losses. The dependence of the energies of emitted low-energy ICD electrons on the initial-state energy is studied. ICD electron energy spectra and KER spectra are obtained separately for fast and slow decay processes where the KER spectra for the slow decay channel are strongly influenced by nuclear motion. The KER and ICD electron energy spectra are well reproduced by ab initio calculations.

Electron Impact Ionization: A New Parameterization for 100 eV to 1 MeV Electrons

NASA Technical Reports Server (NTRS)

Fang, Xiaohua; Randall, Cora E.; Lummerzheim, Dirk; Solomon, Stanley C.; Mills, Michael J.; Marsh, Daniel; Jackman, Charles H.; Wang, Wenbin; Lu, Gang

2008-01-01

Low, medium and high energy electrons can penetrate to the thermosphere (90-400 km; 55-240 miles) and mesosphere (50-90 km; 30-55 miles). These precipitating electrons ionize that region of the atmosphere, creating positively charged atoms and molecules and knocking off other negatively charged electrons. The precipitating electrons also create nitrogen-containing compounds along with other constituents. Since the electron precipitation amounts change within minutes, it is necessary to have a rapid method of computing the ionization and production of nitrogen-containing compounds for inclusion in computationally-demanding global models. A new methodology has been developed, which has parameterized a more detailed model computation of the ionizing impact of precipitating electrons over the very large range of 100 eV up to 1,000,000 eV. This new parameterization method is more accurate than a previous parameterization scheme, when compared with the more detailed model computation. Global models at the National Center for Atmospheric Research will use this new parameterization method in the near future.

Experimental Characterization of Electron Beam Welded SAE 5137H Thick Steel Plate

NASA Astrophysics Data System (ADS)

Kattire, Prakash; Bhawar, Valmik; Thakare, Sandeep; Patil, Sachin; Mane, Santosh; Singh, Rajkumar, Dr.

2017-09-01

Electron beam welding is known for its narrow weld zone with high depth to width ratio, less heat affected zone, less distortion and contamination. Electron beam welding is fusion welding process, where high velocity electrons impinge on material joint to be welded and kinetic energy of this electron is transformed into heat upon impact to fuse the material. In the present work electron beam welding of 60 mm thick SAE 5137H steel is studied. Mechanical and metallurgical properties of electron beam welded joint of SAE 5137H were evaluated. Mechanical properties are analysed by tensile, impact and hardness test. Metallurgical properties are investigated through optical and scanning electron microscope. The hardness traverse across weld zone shows HV 370-380, about 18% increase in the tensile strength and very low toughness of weld joint compared to parent metal. Microstructural observation shows equiaxed dendrite in the fusion zone and partial grain refinement was found in the HAZ.

Sub-Ionospheric Measurements of the Ocean, Atmosphere, and Ionosphere from the CARINA Satellites

NASA Astrophysics Data System (ADS)

Bernhardt, P. A.; Montgomery, J. A., Jr.; Siefring, C. L.; Gatling, G.

2016-12-01

New satellites designed to fly between 150 and 250 km has been constructed to study a wide range of geophysical topics extending from the ocean to the topside ionosphere. The key features of the CARINA satellites are (1) the ability of sustain long duration (60 day) orbits below the F-Layer ionosphere, (2) download large quantities of data (10 GBytes) per pass over a ground station, and (3) a heritage instrument payload comprised of an Electric Field Instrument (EFI) with full range measurements from 3 to 13 MHz, a Ram Langmuir Probe (RLP) the measures ion density from 102 to 106 cm-3 with 10 kHz sample rate, an Orbiting GPS Receiver (OGR) providing overhead total electron content and satellite position and the Wake Retro Reflectors (WRR) that use laser ranging for precise orbit determination. Each letter in "CARINA" represents one of the science objectives. "Coastal" ocean wave remote sensing of the sea surface wave height spectrum derived from HF surface wave scatter to the satellite. Assimilation ionospheric models are supported by Global measurements of GPS total electron count (TEC) and in situ plasma density for updating data driven ionospheric models (GAIM, IDA3D, etc.). Radio wave propagation and interactions determine the impact of the bottomside ionosphere on HF ray trajectories, the effects of ionospheric irregularities that yield UHF/L-band scintillations and ionospheric modifications by high power HF waves. Ionospheric structures such are sporadic-E and intermediate layers, traveling ionospheric disturbances (TID's) and large scale bottomside fluctuations in the F-layer are directly measured by CARINA sensors. Neutral drag is studied along the orbit through reentry modeling of drag coefficients and neutral density model updates. Finally, Atmospherics and lightning knowledge is acquired through studies of lightning EM pulses and their impact on ionosphere. Two CARINA satellites separated by 2000 km flying above 50 degree inclination represents the baseline mission.

Obtaining Networked Scintillation and Total Electron Content Data Across Africa and Asia: Partnering with the IHY/UNBSSI Developing Nations Program

NASA Astrophysics Data System (ADS)

Groves, K. M.; Basu, S.; Erickson, T.; Sunanda, B.; David, B.

2005-12-01

Under the Scintillation Network Decision Aid (SCINDA) project, scientists at the Air Force Research Laboratory (AFRL) have developed a sensor network for the purpose of monitoring low-latitude ionospheric total electron content (TEC) and scintillations associated with equatorial Spread F. In addition to monitoring GPS scintillations, TEC and VHF scintillations, the sensor package measures ionospheric drifts when irregularities are present providing important data on vertical electric fields in the F-region .The network currently consists of twelve stations distributed around the globe and the data have been used to conduct numerous studies on the characteristics and climatology of equatorial scintillation, including the impacts of magnetic storms on the equatorial ionosphere. Notably absent from the existing network are observing sites in Africa where both satellite observations and limited historical data sets suggest significant scintillation activity, though the detailed behavior and longitudinal variations across the continent are largely unknown. The latter aspect, in particular, is of great interest because of substantial changes in the orientation of the geomagnetic field in extreme West Africa that transition to a more uniform field geometry spanning the rest of the continent. Understanding the effects of these changes on scintillation climatology will provide new insights into the processes that trigger equatorial Spread F and assist researchers in developing improved forecasts of such activity. AFRL aims to establish 5-8 monitoring sites across equatorial Africa in collaboration with host nations participating in the United Nations Basic Space Science Initiative during the IHY period. In addition to expanding scientific opportunities, it is hoped that these sites will lead to greater awareness of the significant space weather issues impacting Africa and result in enhanced international collaboration between both African and non-African scientists interested in constructing an improved description of the equatorial ionosphere.

Understanding the optical properties of ZnO1-xSx and ZnO1-xSex alloys

NASA Astrophysics Data System (ADS)

Baldissera, Gustavo; Persson, Clas

2016-01-01

ZnO1-xYx with chalcogen element Y exhibits intriguing optoelectronic properties as the alloying strongly impacts the band-gap energy Eg(x). In this work, we analyze and compare the electronic structures and the dielectric responses of Zn(O,S) and Zn(O,Se) alloys by means of the density functional theory and the partially self-consistent GW approach. We model the crystalline stability from the total energies, and the results indicate that Zn(O,S) is more stable as alloy than Zn(O,Se). We demonstrate also that ion relaxation strongly affects total energies, and that the band-gap bowing depends primarily on local relaxation of the bonds. Moreover, we show that the composition dependent band-gap needs to be analyzed by the band anti-crossing model for small alloying concentration, while the alloying band-bowing model is accurate for strong alloying. We find that the Se-based alloys have a stronger change in the band-gap energy (for instance, ΔEg(0.50) = Eg(ZnO) - Eg(x = 0.50) ≈ 2.2 eV) compared with that of the S-based alloy (ΔEg(0.50) = 1.2 eV), mainly due to a stronger relaxation of the Zn-anion bonds that affects the electronic structure near the band edges. The optical properties of the alloys are discussed in terms of the complex dielectric function ɛ(ω) = ɛ1(ω) + iɛ2(ω) and the absorption coefficient α(ω). While the large band-gap bowing directly impacts the low-energy absorption spectra, the high-frequency dielectric constant ɛ∞ is correlated to the intensity of the dielectric response at energies above 4 eV. Therefore, the dielectric constant is only weakly affected by the non-linear band-gap variation. Despite strong structural relaxation, the high absorption coefficients of the alloys demonstrate that the alloys have well-behaved optoelectronic properties.

Calculation of total electron excitation cross-sections and partial electron ionization cross-sections for the elements. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Green, T. J.

1973-01-01

Computer programs were used to calculate the total electron excitation cross-section for atoms and the partial ionization cross-section. The approximations to the scattering amplitude used are as follows: (1) Born, Bethe, and Modified Bethe for non-exchange excitation; (2) Ochkur for exchange excitation; and (3) Coulomb-Born of non-exchange ionization. The amplitudes are related to the differential cross-sections which are integrated to give the total excitation (or partial ionization) cross-section for the collision. The atomic wave functions used are Hartree-Fock-Slater functions for bound states and the coulomb wave function for the continuum. The programs are presented and the results are examined.

Impact of conflict on medical education: a cross-sectional survey of students and institutions in Iraq

PubMed Central

Barnett-Vanes, Ashton; Shawki, Marwan; Ismail, Omar Abdulkadir; Fung, Chi; Kedia, Tara

2016-01-01

Objective This study surveyed all Iraqi medical schools and a cross-section of Iraqi medical students regarding their institutional and student experiences of medical education amidst ongoing conflict. The objective was to better understand the current resources and challenges facing medical schools, and the impacts of conflict on the training landscape and student experience, to provide evidence for further research and policy development. Setting Deans of all Iraqi medical schools registered in the World Directory of Medical Schools were invited to participate in a survey electronically. Medical students from three Iraqi medical schools were invited to participate in a survey electronically. Outcomes Primary: Student enrolment and graduation statistics; human resources of medical schools; dean perspectives on impact of conflict. Secondary: Medical student perspectives on quality of teaching, welfare and future career intentions. Findings Of 24 medical schools listed in the World Directory of Medical Schools, 15 replied to an initial email sent to confirm their contact details, and 8 medical schools responded to our survey, giving a response rate from contactable medical schools of 53% and overall of 33%. Five (63%) medical schools reported medical student educational attainment being impaired or significantly impaired; 4 (50%) felt the quality of training medical schools could offer had been impaired or significantly impaired due to conflict. A total of 197 medical students responded, 62% of whom felt their safety had been threatened due to violent insecurity. The majority (56%) of medical students intended to leave Iraq after graduating. Conclusions Medical schools are facing challenges in staff recruitment and adequate resource provision; the majority believe quality of training has suffered as a result. Medical students are experiencing added psychological stress and lower quality of teaching; the majority intend to leave Iraq after graduation. PMID:26883241

An inadvertent capture cell for orbital debris and micrometeorites - The main electronics box thermal blanket of the solar maximum satellite

NASA Technical Reports Server (NTRS)

Rietmeijer, F. J. M.; Schramm, L. S.; Barrett, R. A.; Mckay, D. S.; Zook, H. A.

1986-01-01

The physical properties of impact features in the Solar Max main electronics box thermal blanket are consistent with hypervelocity impacts of particles in the near-earth space environment. The majority of particles are orbital debris and include spacecraft paints and bismuth-rich particles. At least 30 percent of all impact features are caused by micrometeorites, which include silicates and sulfides. Some micrometeorites survive impact with only minor shock-metamorphic effects or chemical fractionation. Currently calibration experiments are under way to relate flux to particle diameter (or mass).

Patient No-Show Predictive Model Development using Multiple Data Sources for an Effective Overbooking Approach

PubMed Central

Hanauer, D.A.

2014-01-01

Summary Background Patient no-shows in outpatient delivery systems remain problematic. The negative impacts include underutilized medical resources, increased healthcare costs, decreased access to care, and reduced clinic efficiency and provider productivity. Objective To develop an evidence-based predictive model for patient no-shows, and thus improve overbooking approaches in outpatient settings to reduce the negative impact of no-shows. Methods Ten years of retrospective data were extracted from a scheduling system and an electronic health record system from a single general pediatrics clinic, consisting of 7,988 distinct patients and 104,799 visits along with variables regarding appointment characteristics, patient demographics, and insurance information. Descriptive statistics were used to explore the impact of variables on show or no-show status. Logistic regression was used to develop a no-show predictive model, which was then used to construct an algorithm to determine the no-show threshold that calculates a predicted show/no-show status. This approach aims to overbook an appointment where a scheduled patient is predicted to be a no-show. The approach was compared with two commonly-used overbooking approaches to demonstrate the effectiveness in terms of patient wait time, physician idle time, overtime and total cost. Results From the training dataset, the optimal error rate is 10.6% with a no-show threshold being 0.74. This threshold successfully predicts the validation dataset with an error rate of 13.9%. The proposed overbooking approach demonstrated a significant reduction of at least 6% on patient waiting, 27% on overtime, and 3% on total costs compared to other common flat-overbooking methods. Conclusions This paper demonstrates an alternative way to accommodate overbooking, accounting for the prediction of an individual patient’s show/no-show status. The predictive no-show model leads to a dynamic overbooking policy that could improve patient waiting, overtime, and total costs in a clinic day while maintaining a full scheduling capacity. PMID:25298821

Plasma Relaxation and Topological Aspects in Electron Magnetohydrodynamics

NASA Astrophysics Data System (ADS)

Shivamoggi, Bhimsen

2016-10-01

Parker's formulation of isotopological plasma relaxation process toward minimum magnetics energy states in magnetohydrodynamics (MHD) is extended to electron MHD (EMHD). The lower bound on magnetic energy in EMHD is determined by both the magnetic field and the electron vorticity field topologies, and is shown to be reduced further in EMHD by an amount proportional to the sum of total electron-flow kinetic energy and total electron-flow enstrophy. The EMHD Beltrami condition becomes equivalent to the potential vorticity conservation equation in two-dimensional (2D) hydrodynamics, and the torsion coefficient and turns out to be proportional to potential vorticity. The winding pattern of the magnetic field lines appears to evolve therefore in the same way as potential vorticity lines in 2D hydrodynamics.

Plasma relaxation and topological aspects in electron magnetohydrodynamics

NASA Astrophysics Data System (ADS)

Shivamoggi, B. K.

2016-07-01

Parker's formulation of isotopological plasma relaxation process toward minimum magnetics energy states in magnetohydrodynamics (MHD) is extended to electron MHD (EMHD). The lower bound on magnetic energy in EMHD is determined by both the magnetic field and the electron vorticity field topologies, and is shown to be reduced further in EMHD by an amount proportional to the sum of total electron-flow kinetic energy and total electron-flow enstrophy. The EMHD Beltrami condition becomes equivalent to the potential vorticity conservation equation in two-dimensional (2D) hydrodynamics, and the torsion coefficient α turns out to be proportional to potential vorticity. The winding pattern of the magnetic field lines appears to evolve, therefore, in the same way as potential vorticity lines in 2D hydrodynamics.

Laboratory Studies of Charging Properties of Dust Grains in Astrophysical/Planetary Environments

NASA Technical Reports Server (NTRS)

Tankosic, D.; Abbas, M. M.

2012-01-01

Dust grains in various astrophysical environments are generally charged electrostatically by photoelectric emissions with UV/X-ray radiation, as well as by electron/ion impact. Knowledge of physical and optical properties of individual dust grains is required for understanding of the physical and dynamical processes in space environments and the role of dust in formation of stellar and planetary systems. In this paper we focus on charging of individual micron/submicron dust grains by processes that include: (a) UV photoelectric emissions involving incident photon energies higher than the work function of the material and b) electron impact, where low energy electrons are scattered or stick to the dust grains, thereby charging the dust grains negatively, and at sufficiently high energies the incident electrons penetrate the grain leading to excitation and emission of electrons referred to as secondary electron emission (SEE). It is well accepted that the charging properties of individual micron/submicron size dust grains are expected to be substantially different from the bulk materials. However, no viable models for calculation of the charging properties of individual micron size dust grains are available at the present time. Therefore, the photoelectric yields, and secondary electron emission yields of micron-size dust grains have to be obtained by experimental methods. Currently, very limited experimental data are available for charging of individual micron-size dust grains. Our experimental results, obtained on individual, micron-size dust grains levitated in an electrodynamic balance facility (at NASA-MSFC), show that: (1) The measured photoelectric yields are substantially higher than the bulk values given in the literature and indicate a particle size dependence with larger particles having order-of-magnitude higher values than for submicron-size grains; (2) dust charging by low energy electron impact is a complex process. Also, our measurements indicate that the electron impact may lead to charging or discharging of dust grains depending upon the grain size, surface potential, electron energy, electron flux, grain composition, and configuration (e.g. Abbas et al, 2010). Laboratory measurements on charging of analogs of the interstellar dust as well as Apollo 11 dust grains conducted at the NASA-MSFC Dusty Plasma Lab. are presented here

Thermal and electron transport studies on the valence fluctuating compound YbNiAl4

NASA Astrophysics Data System (ADS)

Falkowski, M.; Kowalczyk, A.

2018-05-01

We report the thermoelectric power S and thermal conductivity κ measurements on the valence fluctuating compound YbNiAl4, furthermore taking into account the impact of the applied magnetic field. We discuss our new results with revisiting the magnetic [χ(T)], transport [ρ(T)], and thermodynamic [Cp(T)] properties in order to better understand the phenomenon of thermal and electron transport in this compound. The field dependence of the magnetoresistivity data is also given. The temperature dependence of thermoelectric power S(T) was found to exhibit a similar behaviour as expected for Yb-based compounds with divalent or nearly divalent Yb ions. In addition, the values of total thermal conductivity as a function of temperature κ(T) of YbNiAl4 are fairly low compared to those of pure metals which may be linked to the fact that the conduction band is perturbed by strong hybridization. A deeper analysis of the specific heat revealed the low-T anomaly of the ratio Cp(T)/T3, most likely associated with the localized low-frequency oscillators in this alloy. In addition, the Kadowaki-Woods ratio and the Wilson ratio are discussed with respect to the electronic correlations in YbNiAl4.

Possible modification of the cooling index of interstellar helium pickup ions by electron impact ionization in the inner heliosphere

NASA Astrophysics Data System (ADS)

Chen, Jun Hong; Bochsler, Peter; Möbius, Eberhard; Gloeckler, George

2014-09-01

Interstellar neutrals penetrating into the inner heliosphere are ionized by photoionization, charge exchange with solar wind ions, and electron impact ionization. These processes comprise the first step in the evolution of interstellar pickup ion (PUI) distributions. Typically, PUI distributions have been described in terms of velocity distribution functions that cool adiabatically under solar wind expansion, with a cooling index of 3/2. Recently, the cooling index has been determined experimentally in observations of He PUI distributions with Advanced Composition Explorer (ACE)/Solar Wind Ion Composition Spectrometer and found to vary substantially over the solar cycle. The experimental determination of the cooling index depends on the knowledge of the ionization rates and their spatial variation. Usually, ionization rates increase with 1/r2 as neutral particles approach the Sun, which is not exactly true for electron impact ionization, because the electron temperature increases with decreasing distance from the Sun due to the complexity of its distributions and different radial gradients in temperature. This different dependence on distance may become important in the study of the evolution of PUI distributions and is suspected as one of the potential reasons for the observed variation of the cooling index. Therefore, we investigate in this paper the impact of electron ionization on the variability of the cooling index. We find that the deviation of the electron ionization rate from the canonical 1/r2 behavior of other ionization processes plays only a minor role.

Measurement of the total spectrum of electrons and positrons in the energy range of 300–1500 GeV in the PAMELA experiment with the aid of a sampling calorimeter and a neutron detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karelin, A. V., E-mail: karelin@hotbox.ru; Voronov, S. A.; Galper, A. M.

2015-03-15

A method based on the use of a sampling calorimeter was developed for measuring the total energy spectrum of electrons and positrons from high-energy cosmic rays in the PAMELA satellite-borne experiment. This made it possible to extend the range of energies accessible to measurements by the magnetic system of the PAMELA spectrometer. Themethod involves a procedure for selecting electrons on the basis of features of a secondary-particle shower in the calorimeter. The results obtained by measuring the total spectrum of cosmic-ray electrons and positrons in the energy range of 300–1500 GeV by the method in question are presented on themore » basis of data accumulated over a period spanning 2006 and 2013.« less

Ionospheric responses during equinox and solstice periods over Turkey

NASA Astrophysics Data System (ADS)

Karatay, Secil; Cinar, Ali; Arikan, Feza

2017-11-01

Ionospheric electron density is the determining variable for investigation of the spatial and temporal variations in the ionosphere. Total Electron Content (TEC) is the integral of the electron density along a ray path that indicates the total variability through the ionosphere. Global Positioning System (GPS) recordings can be utilized to estimate the TEC, thus GPS proves itself as a useful tool in monitoring the total variability of electron distribution within the ionosphere. This study focuses on the analysis of the variations of ionosphere over Turkey that can be grouped into anomalies during equinox and solstice periods using TEC estimates obtained by a regional GPS network. It is observed that noon time depletions in TEC distributions predominantly occur in winter for minimum Sun Spots Numbers (SSN) in the central regions of Turkey which also exhibit high variability due to midlatitude winter anomaly. TEC values and ionospheric variations at solstice periods demonstrate significant enhancements compared to those at equinox periods.

Recent Total Ionizing Dose Results and Displacement Damage Results for Candidate Spacecraft Electronics for NASA

NASA Technical Reports Server (NTRS)

Cochran, Donna J.; Buchner, Stephen P.; Irwin, Tim L.; LaBel, Kenneth A.; Marshall, Cheryl J.; Reed, Robert A.; Sanders, Anthony B.; Hawkins, Donald K.; Flanigan, Ryan J.; Cox, Stephen R.

2005-01-01

We present data on the vulnerability of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage. Devices tested include optoelectronics, digital, analog, linear bipolar devices, hybrid devices, Analog-to- Digital Converters (ADCs), and Digital-to-Analog Converters (DACs), among others. T

Compendium of Single Event Effects, Total Ionizing Dose, and Displacement Damage for Candidate Spacecraft Electronics for NASA

NASA Technical Reports Server (NTRS)

LaBel, Kenneth A.; O'Bryan, Martha V.; Chen, Dakai; Campola, Michael J.; Casey, Megan C.; Pellish, Jonathan A.; Lauenstein, Jean-Marie; Wilcox, Edward P.; Topper, Alyson D.; Ladbury, Raymond L.;

Impact of add-on laboratory testing at an academic medical center: a five year retrospective study.

PubMed

Nelson, Louis S; Davis, Scott R; Humble, Robert M; Kulhavy, Jeff; Aman, Dean R; Krasowski, Matthew D

2015-01-01

Clinical laboratories frequently receive orders to perform additional tests on existing specimens ('add-ons'). Previous studies have examined add-on ordering patterns over short periods of time. The objective of this study was to analyze add-on ordering patterns over an extended time period. We also analyzed the impact of a robotic specimen archival/retrieval system on add-on testing procedure and manual effort. In this retrospective study at an academic medical center, electronic health records from were searched to obtain all add-on orders that were placed in the time period of May 2, 2009 to December 31, 2014. During the time period of retrospective study, 880,359 add-on tests were ordered on 96,244 different patients. Add-on testing comprised 3.3 % of total test volumes. There were 443,411 unique ordering instances, leading to an average of 1.99 add-on tests per instance. Some patients had multiple episodes of add-on test orders at different points in time, leading to an average of 9.15 add-on tests per patient. The majority of add-on orders were for chemistry tests (78.8 % of total add-ons) with the next most frequent being hematology and coagulation tests (11.2 % of total add-ons). Inpatient orders accounted for 66.8 % of total add-on orders, while the emergency department and outpatient clinics had 14.8 % and 18.4 % of total add-on orders, respectively. The majority of add-ons were placed within 8 hours (87.3 %) and nearly all by 24 hours (96.8 %). Nearly 100 % of add-on orders within the emergency department were placed within 8 hours. The introduction of a robotic specimen archival/retrieval unit saved an average of 2.75 minutes of laboratory staff manual time per unique add-on order. This translates to 24.1 hours/day less manual effort in dealing with add-on orders. Our study reflects the previous literature in showing that add-on orders significantly impact the workload of the clinical laboratory. The majority of add-on orders are clinical chemistry tests, and most add-on orders occur within 24 hours of original specimen collection. Robotic specimen archival/retrieval units can reduce manual effort in the clinical laboratory associated with add-on orders.

Recycling of engineering plastics from waste electrical and electronic equipments: influence of virgin polycarbonate and impact modifier on the final performance of blends.

PubMed

Ramesh, V; Biswal, Manoranjan; Mohanty, Smita; Nayak, Sanjay K

2014-05-01

This study is focused on the recovery and recycling of plastics waste, primarily polycarbonate, poly(acrylonitrile-butadiene-styrene) and high impact polystyrene, from end-of-life waste electrical and electronic equipments. Recycling of used polycarbonate, acrylonitrile-butadiene-styrene, polycarbonate/acrylonitrile-butadiene-styrene and acrylonitrile-butadiene-styrene/high impact polystrene material was carried out using material recycling through a melt blending process. An optimized blend composition was formulated to achieve desired properties from different plastics present in the waste electrical and electronic equipments. The toughness of blended plastics was improved with the addition of 10 wt% of virgin polycarbonate and impact modifier (ethylene-acrylic ester-glycidyl methacrylate). The mechanical, thermal, dynamic-mechanical and morphological properties of recycled blend were investigated. Improved properties of blended plastics indicate better miscibility in the presence of a compatibilizer suitable for high-end application.

Validation of the work and health interview.

PubMed

Stewart, Walter F; Ricci, Judith A; Leotta, Carol; Chee, Elsbeth

2004-01-01

Instruments that measure the impact of illness on work do not usually provide a measure that can be directly translated into lost hours or costs. We describe the validation of the Work and Health Interview (WHI), a questionnaire that provides a measure of lost productive time (LPT) from work absence and reduced performance at work. A sample (n = 67) of inbound phone call agents was recruited for the study. Validity of the WHI was assessed over a 2-week period in reference to workplace data (i.e. absence time, time away from call station and electronic continuous performance) and repeated electronic diary data (n = 48) obtained approximately eight times a day to estimate time not working (i.e. a component of reduced performance). The mean (median) missed work time estimate for any reason was 11 (8.0) and 12.9 (8.0) hours in a 2-week period from the WHI and workplace data, respectively, with a Pearson's (Spearman's) correlation of 0.84 (0.76). The diary-based mean (median) estimate of time not working while at work was 3.9 (2.8) hours compared with the WHI estimate of 5.7 (3.2) hours with a Pearson's (Spearman's) correlation of 0.19 (0.33). The 2-week estimate of total productive time from the diary was 67.2 hours compared with 67.8 hours from the WHI, with a Pearson's (Spearman's) correlation of 0.50 (0.46). At a population level, the WHI provides an accurate estimate of missed time from work and total productive time when compared with workplace and diary estimates. At an individual level, the WHI measure of total missed time, but not reduced performance time, is moderately accurate.

Relations among several nuclear and electronic density functional reactivity indexes

NASA Astrophysics Data System (ADS)

Torrent-Sucarrat, Miquel; Luis, Josep M.; Duran, Miquel; Toro-Labbé, Alejandro; Solà, Miquel

2003-11-01

An expansion of the energy functional in terms of the total number of electrons and the normal coordinates within the canonical ensemble is presented. A comparison of this expansion with the expansion of the energy in terms of the total number of electrons and the external potential leads to new relations among common density functional reactivity descriptors. The formulas obtained provide explicit links between important quantities related to the chemical reactivity of a system. In particular, the relation between the nuclear and the electronic Fukui functions is recovered. The connection between the derivatives of the electronic energy and the nuclear repulsion energy with respect to the external potential offers a proof for the "Quantum Chemical le Chatelier Principle." Finally, the nuclear linear response function is defined and the relation of this function with the electronic linear response function is given.

Life cycle assessment of second generation (2G) and third generation (3G) mobile phone networks.

PubMed

Scharnhorst, Wolfram; Hilty, Lorenz M; Jolliet, Olivier

2006-07-01

The environmental performance of presently operated GSM and UMTS networks was analysed concentrating on the environmental effects of the End-of-Life (EOL) phase using the Life Cycle Assessment (LCA) method. The study was performed based on comprehensive life cycle inventory and life cycle modelling. The environmental effects were quantified using the IMPACT2002+ method. Based on technological forecasts, the environmental effects of forthcoming mobile telephone networks were approximated. The results indicate that a parallel operation of GSM and UMTS networks is environmentally detrimental and the transition phase should be kept as short as possible. The use phase (i.e. the operation) of the radio network components account for a large fraction of the total environmental impact. In particular, there is a need to lower the energy consumption of those network components. Seen in relation to each other, UMTS networks provide an environmentally more efficient mobile communication technology than GSM networks. In assessing the EOL phase, recycling the electronic scrap of mobile phone networks was shown to have clear environmental benefits. Under the present conditions, material recycling could help lower the environmental impact of the production phase by up to 50%.

Social and occupational factors associated with psychological wellbeing among occupational groups affected by disaster: a systematic review.

PubMed

Brooks, Samantha K; Dunn, Rebecca; Amlôt, Richard; Rubin, G James; Greenberg, Neil

2017-08-01

The psychological impact of disasters has been well-documented; less attention has been paid to factors affecting the wellbeing of those exposed to disasters as occupational groups. To conduct a systematic literature review identifying social and occupational factors affecting the wellbeing of disaster-exposed employees; to use these factors to identify recommendations for potential interventions. Four electronic literature databases were searched; reference lists of relevant papers were hand-searched. A total of 18 005 papers were found, 571 full texts were read and 36 included in the review. The psychological impact of disasters on employees was associated with pre-disaster factors (experience/training; income; life events/health; job satisfaction), peri-disaster factors (exposure; peri-traumatic experiences; perceptions of safety; injury), social factors (organisational support; social support generally) and post-disaster factors (impact on life). It is important to build a resilient workforce outside of a crisis. Pre-disaster training in recognising signs of distress, understanding vulnerability factors such as those described above, which may put certain employees at greater risk of distress and how to support colleagues may be useful. Further research into the effectiveness of post-disaster interventions is needed.

Recent Geoeffective Space Weather Events and Technological System Impacts

NASA Astrophysics Data System (ADS)

Redmon, R. J.; Denig, W. F.; Loto'aniu, P. T. M.; Singer, H. J.; Wilkinson, D. C.; Knipp, D. J.; Kilcommons, L. M.

2015-12-01

We review the state of the space environment for three recent intense geoeffective storms using NOAA observations and model predictions. On February 27, 2014, the US Wide Area Augmentation System (WAAS) navigation service over eastern Alaska and northeastern continental US was degraded due to a strong ionospheric storm. Similarly, on March 17, the St. Patrick's Day geomagnetic storm commenced, resulting in the most intense storm of the solar cycle to date with mid-latitude auroral sightings, intense ionospheric irregularities and WAAS degradation. On June 22, a strong (G4) geomagnetic storm commenced following the impact of 3 coronal mass ejections (CMEs). Late on June 22, solar protons entered the polar regions along open magnetic field lines producing intense radio absorption. We summarize, compare and contrast the space environmental state for each of these events from the perspective of NOAA observations and model predictions. We do so by leveraging GOES and POES/MetOp observations of the space radiation environment, DMSP observations of precipitating particles and bulk plasma parameters, OVATION Prime predictions of the auroral energy input and the US Total Electron Content (USTEC) and D-Region Absorption Prediction (DRAP) modeled response of the ionosphere. We discuss impacts to technological systems as available.

The effect of impurities and incident angle on the secondary electron emission of Ni(110)

NASA Astrophysics Data System (ADS)

Lazar, Hadar; Patino, Marlene; Raitses, Yevgeny; Koel, Bruce E.; Gentile, Charles; Feibush, Eliot

2015-11-01

The investigation of secondary electron emission (SEE) of conducting materials used for magnetic fusion devices and plasma thrusters is important for determining device lifetime and performance. Methods to quantify the secondary electron emission from conducting materials and to characterize the effects that impurities and incident angles have on secondary electron emission were developed using 4-grid low energy electron diffraction (LEED) optics. The total secondary electron yield from a Ni(110) surface was continuously measured from the sample current as surface contamination increased from reactions with background gases in the ultrahigh vacuum chamber. Auger electron spectroscopy (AES) and temperature programmed desorption (TPD) were used to examine the composition and impurity levels on the Ni(110) surface. The total secondary electron yield was also measured at different incident angles. Thank you to the Princeton Plasma Physics Laboratory and the Department of Energy for the opportunity to work on this project through the Science Undergraduate Laboratory Internships.

The effects of impurities and incidence angle on the secondary electron emission of Ni(110)

NASA Astrophysics Data System (ADS)

Lazar, Hadar; Patino, Marlene; Raitses, Yevgeny; Koel, Bruce; Gentile, Charles; Feibush, Eliot

The investigation of secondary electron emission (SEE) of conducting materials used for magnetic fusion devices and plasma thrusters is important for determining device lifetime and performance. Methods to quantify the secondary electron emission from conducting materials and to characterize the effects that impurities and incidence angles have on secondary electron emission were developed using 4-grid low energy electron diffraction (LEED) optics. The total secondary electron yield from a Ni(110) surface was continuously measured from the sample current as surface contamination increased from reactions with background gases in the ultrahigh vacuum chamber. Auger electron spectroscopy (AES) and temperature programmed desorption (TPD) were used to examine the composition and impurity levels on the Ni(110) surface. The total secondary electron yield was also measured at different incidence angles. Thank you to the Princeton Plasma Physics Laboratory (PPPL) and the Department of Energy (DOE) for the opportunity to work on this project through the Science Undergraduate Laboratory Internships (SULI).

Cherenkov imaging for Total Skin Electron Therapy (TSET)

NASA Astrophysics Data System (ADS)

Xie, Yunhe; Petroccia, Heather; Maity, Amit; Miao, Tianshun; Zhu, Yihua; Bruza, Petr; Pogue, Brian W.; Andreozzi, Jacqueline M.; Plastaras, John P.; Dong, Lei; Zhu, Timothy C.

2018-03-01

Total Skin Electron Therapy (TSET) utilizes high-energy electrons to treat cancers on the entire body surface. The otherwise invisible radiation beam can be observed via the optical Cherenkov photons emitted from interaction between the high-energy electron beam and tissue. Using a specialized camera-system, the Cherenkov emission can thus be used to evaluate the dose uniformity on the surface of the patient in real-time. Each patient was also monitored during TSET via in-vivo detectors (IVD) in nine locations. Patients undergoing TSET in various conditions (whole body and half body) were imaged and analyzed, and the viability of the system to provide clinical feedback was established.

Calculated stopping powers of low-energy electrons in some materials of interest in radiation protection.

PubMed

Akande, W

1993-03-01

Stopping powers of low-energy (< 10 keV) electrons in aluminum, copper, cesium, barium, lead, lithium, and uranium were calculated using an analytic method. The interaction of the electrons with the materials were characterized in terms of three cross sections for total ionization and total scattering. Experimental cross section data were collated, where available, for the materials. The expressions were then fitted to the data to obtain the values of the relevant constants in the expressions. This enabled the basic equation of stopping powers of electrons to be evaluated for the materials. Comparison of the results obtained with those of other workers was affected.

Electronic wave function and binding effects in M-shell ionization of gold by protons

NASA Astrophysics Data System (ADS)

Pajek, M.; Banaś, D.; Jabłoński, Ł.; Mukoyama, T.

2018-02-01

The measured M-X-ray production cross sections for protons, which are used in the particle induced X-ray emission (PIXE) technique, are systematically underestimated for low impact energies by the ECPSSR and ECUSAR theories. These theories, which are based on the plane wave Born approximation (PWBA) and use the screened hydrogenic wave functions, include corrections for the projectile Coulomb deflection and electron relativistic and binding effects. In the present paper, in order to interpret the observed disagreement at low impact energies, the systematic calculations of the M-shell ionization cross sections for gold were performed using the semiclassical (SCA) and the binary encounter (BEA) approximations in order to identify a role of the electronic wave function and electron binding effects. In these calculations the different wave functions, from nonrelativistic hydrogenic to selfconsistent Dirac-Hartree-Fock, were considered and the binding effect was treated within extreme separated- (SA) and united-atoms (UA) limits. The results are discussed in details and the observed discrepancies are attributed to inadequate description of the electron binding effect at the lowest impact energies for which the molecular approach is required.

The Use of Electronic Information Services and Information Literacy: A Glasgow Caledonian University Study

ERIC Educational Resources Information Center

Crawford, John

2006-01-01

The study was undertaken as part of the LIRG/SCONUL Value and Impact study and sought to establish direct evidence of the impact of electronic information services (EIS) on Glasgow Caledonian University students, both past and present. Evidence of the spread of information literacy among students and alumni was also sought. An electronic…

Impact of Electronic Teaching Materials on Process of Education--Results of an Experiment

ERIC Educational Resources Information Center

Záhorec, Ján; Hašková, Alena; Munk, Michal

2010-01-01

In their paper the authors deal with the vital issues of creation and application of electronic teaching materials for natural science subjects teaching. They describe an experimental examination of qualitative impact of these aids on education. The authors present a part of research results, which they obtained in a major research focused on…

Wigner distributions for an electron

NASA Astrophysics Data System (ADS)

Kumar, Narinder; Mondal, Chandan

2018-06-01

We study the Wigner distributions for a physical electron, which reveal the multidimensional images of the electron. The physical electron is considered as a composite system of a bare electron and photon. The Wigner distributions for unpolarized, longitudinally polarized and transversely polarized electron are presented in transverse momentum plane as well as in impact-parameter plane. The spin-spin correlations between the bare electron and the physical electron are discussed. We also evaluate all the leading twist generalized transverse momentum distributions (GTMDs) for electron.

Eye injuries from electrical weapon probes: Incidents, prevalence, and legal implications.

PubMed

Kroll, Mark W; Ritter, Mollie B; Kennedy, Eric A; Silverman, Nora K; Shinder, Roman; Brave, Michael A; Williams, Howard E

2018-04-01

While generally reducing morbidity and mortality, electrical weapons have risks associated with their usage, including burn injuries and trauma associated with uncontrolled fall impacts. However, the prevalence of significant eye injury has not been investigated. We searched for incidents of penetrating eye injury from TASER ® conducted electrical weapon (CEW) probes via open source media, litigation filings, and a survey of CEW law-enforcement master instructors. We report 20 previously-unpublished cases of penetrating eye injury from electrical weapon probes in law-enforcement field uses. Together with the 8 previously published cases, there are a total of 28 cases out of 3.44 million field uses, giving a demonstrated CEW field-use risk of penetrating eye injury of approximately 1:123 000. Confidence limits [85 000, 178 000] by Wilson score interval. There have been 18 cases of total unilateral blindness or enucleation. We also present legal decisions on this topic. The use of electrical weapons presents a rare but real risk of total or partial unilateral blindness from electrical weapon probes. Catastrophic eye injuries appear to be the dominant non-fatal complication of electronic control. Copyright © 2018 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

The Impact of Information Culture on Patient Safety Outcomes

PubMed Central

Mikkonen, Santtu; Saranto, Kaija; Bates, David W.

2017-01-01

Summary Background An organization’s information culture and information management practices create conditions for processing patient information in hospitals. Information management incidents are failures that could lead to adverse events for the patient if they are not detected. Objectives To test a theoretical model that links information culture in acute care hospitals to information management incidents and patient safety outcomes. Methods Reason’s model for the stages of development of organizational accidents was applied. Study data were collected from a cross-sectional survey of 909 RNs who work in medical or surgical units at 32 acute care hospitals in Finland. Structural equation modeling was used to assess how well the hypothesized model fit the study data. Results Fit indices indicated a good fit for the model. In total, 18 of the 32 paths tested were statistically significant. Documentation errors had the strongest total effect on patient safety outcomes. Organizational guidance positively affected information availability and utilization of electronic patient records, whereas the latter had the strongest total effect on the reduction of information delays. Conclusions Patient safety outcomes are associated with information management incidents and information culture. Further, the dimensions of the information culture create work conditions that generate errors in hospitals. PMID:28272647

The Impact of Information Culture on Patient Safety Outcomes. Development of a Structural Equation Model.

PubMed

Jylhä, Virpi; Mikkonen, Santtu; Saranto, Kaija; Bates, David W

2017-03-08

An organization's information culture and information management practices create conditions for processing patient information in hospitals. Information management incidents are failures that could lead to adverse events for the patient if they are not detected. To test a theoretical model that links information culture in acute care hospitals to information management incidents and patient safety outcomes. Reason's model for the stages of development of organizational accidents was applied. Study data were collected from a cross-sectional survey of 909 RNs who work in medical or surgical units at 32 acute care hospitals in Finland. Structural equation modeling was used to assess how well the hypothesized model fit the study data. Fit indices indicated a good fit for the model. In total, 18 of the 32 paths tested were statistically significant. Documentation errors had the strongest total effect on patient safety outcomes. Organizational guidance positively affected information availability and utilization of electronic patient records, whereas the latter had the strongest total effect on the reduction of information delays. Patient safety outcomes are associated with information management incidents and information culture. Further, the dimensions of the information culture create work conditions that generate errors in hospitals.

A narrative review of research impact assessment models and methods.

PubMed

Milat, Andrew J; Bauman, Adrian E; Redman, Sally

2015-03-18

Research funding agencies continue to grapple with assessing research impact. Theoretical frameworks are useful tools for describing and understanding research impact. The purpose of this narrative literature review was to synthesize evidence that describes processes and conceptual models for assessing policy and practice impacts of public health research. The review involved keyword searches of electronic databases, including MEDLINE, CINAHL, PsycINFO, EBM Reviews, and Google Scholar in July/August 2013. Review search terms included 'research impact', 'policy and practice', 'intervention research', 'translational research', 'health promotion', and 'public health'. The review included theoretical and opinion pieces, case studies, descriptive studies, frameworks and systematic reviews describing processes, and conceptual models for assessing research impact. The review was conducted in two phases: initially, abstracts were retrieved and assessed against the review criteria followed by the retrieval and assessment of full papers against review criteria. Thirty one primary studies and one systematic review met the review criteria, with 88% of studies published since 2006. Studies comprised assessments of the impacts of a wide range of health-related research, including basic and biomedical research, clinical trials, health service research, as well as public health research. Six studies had an explicit focus on assessing impacts of health promotion or public health research and one had a specific focus on intervention research impact assessment. A total of 16 different impact assessment models were identified, with the 'payback model' the most frequently used conceptual framework. Typically, impacts were assessed across multiple dimensions using mixed methodologies, including publication and citation analysis, interviews with principal investigators, peer assessment, case studies, and document analysis. The vast majority of studies relied on principal investigator interviews and/or peer review to assess impacts, instead of interviewing policymakers and end-users of research. Research impact assessment is a new field of scientific endeavour and there are a growing number of conceptual frameworks applied to assess the impacts of research.

The derivative discontinuity of the exchange-correlation functional.

PubMed

Mori-Sánchez, Paula; Cohen, Aron J

2014-07-28

The derivative discontinuity is a key concept in electronic structure theory in general and density functional theory in particular. The electronic energy of a quantum system exhibits derivative discontinuities with respect to different degrees of freedom that are a consequence of the integer nature of electrons. The classical understanding refers to the derivative discontinuity of the total energy as a function of the total number of electrons (N), but it can also manifest at constant N. Examples are shown in models including several hydrogen systems with varying numbers of electrons or nuclear charge (Z), as well as the 1-dimensional Hubbard model (1DHM). Two sides of the problem are investigated: first, the failure of currently used approximate exchange-correlation functionals in DFT and, second, the importance of the derivative discontinuity in the exact electronic structure of molecules, as revealed by full configuration interaction (FCI). Currently, all approximate functionals, including hybrids, miss the derivative discontinuity, leading to basic errors that can be seen in many ways: from the complete failure to give the total energy of H2 and H2(+), to the missing gap in Mott insulators such as stretched H2 and the thermodynamic limit of the 1DHM, or a qualitatively incorrect density in the HZ molecule with two electrons and incorrect electron transfer processes. Description of the exact particle behaviour of electrons is emphasised, which is key to many important physical processes in real systems, especially those involving electron transfer, and offers a challenge for the development of new exchange-correlation functionals.

Identification of Possible Interstellar Dust Impact Craters on Stardust Foil I033N,1

NASA Astrophysics Data System (ADS)

Ansari, A.; ISPE Team; 29,000 Stardust@home Dusters

2011-12-01

The Interstellar Dust Collector onboard NASA's Stardust Mission - the first to return solid extraterrestrial material to Earth from beyond the Moon - was exposed to the interstellar dust stream for a total of 229 days prior to the spacecraft's return in 2006 [1]. Aluminum foils and aerogel tiles on the collector may have captured the first samples of contemporary interstellar dust. Interstellar Preliminary Examination (ISPE) focuses in part on crater identification and analysis of residue within the craters to determine the nature and origin of the impacting particles. Thus far, ISPE has focused on nine foils and found a total of 20 craters. The number density of impact craters on the foils exceeds by far estimates made from interstellar flux calculations [2]. To identify craters, foil I1033N,1 was scanned with the Field Museum's Evo 60 Scanning Electron Microscope (SEM) at a resolution of 52 nm/pixel with a 15 kV and 170-240 pA beam. Contamination was monitored according to the ISPE protocol: four 4 μm × 3 μm areas of C layers of different thicknesses on a Stardust-type Al foil were irradiated 20 times for 50 s each, while the C and Al signals were recorded with energy-dispersive X-ray spectroscopy (EDS). The C/Al ratio did not increase after 20 repetitions on each of the four areas. The same experiment repeated 7 months later yielded identical results. Thus, analysis with the SEM results in no detectable contamination. Crater candidates were manually selected from SEM images, then reimaged at higher resolution (17 nm/pixel) in order to eliminate false detections. The foil was then sent to Washington University for Auger Nanoprobe elemental analysis of crater 11_175 (diam. 1.1 μm), and to the Naval Research Laboratory for focused ion beam work and transmission electron microscopy and EDS. Twelve crater candidates (diam. 0.28 - 1.1 μm), both elliptical and circular, were identified. The number density of craters on foil 1033N is 15.8 cm^-2. Auger measurements of crater 11_175 revealed the presence of C, O, Al, Si, a small amount of Na, and possibly Ce and Zn [3] - both components of solar cell cover glass - indicating that this particular crater resulted from a particle that impacted the spacecraft's solar panels. TEM/EDS analysis determined the presence of solar cell glass.

Absolute differential cross sections for electron impact excitation of the 10.8-11.5 eV energy-loss states of CO2

NASA Astrophysics Data System (ADS)

Green, M. A.; Teubner, P. J. O.; Campbell, L.; Brunger, M. J.; Hoshino, M.; Ishikawa, T.; Kitajima, M.; Tanaka, H.; Itikawa, Y.; Kimura, M.; Buenker, R. J.

2002-02-01

Absolute differential cross sections (DCSs) for electron impact excitation of electronic states of CO2 in the 10.8-11.5 eV energy-loss range are reported. These data were obtained at the incident electron energies 20,30,60,100 and 200 eV and over the scattered electron angular range 3.5°-90°. The accuracy of our experimental methods has been established independently by using several different normalization techniques at both Sophia and Flinders Universities. Generalized oscillator strengths were derived from our measured DCSs and then extrapolated to zero momentum transfer, in order to determine the optical oscillator strengths. These optical oscillator strengths, where possible, are compared with the results from previous measurements and calculations.

New constraints for low-momentum electronic excitations in condensed matter: fundamental consequences from classical and quantum dielectric theory.

PubMed

Chantler, C T; Bourke, J D

2015-11-18

We present new constraints for the transportation behaviour of low-momentum electronic excitations in condensed matter systems, and demonstrate that these have both a fundamental physical interpretation and a significant impact on the description of low-energy inelastic electron scattering. The dispersion behaviour and characteristic lifetime properties of plasmon and single-electron excitations are investigated using popular classical, semi-classical and quantum dielectric models. We find that, irrespective of constrained agreement to the well known high-momentum and high-energy Bethe ridge limit, standard descriptions of low-momentum electron excitations are inconsistent and unphysical. These observations have direct impact on calculations of transport properties such as inelastic mean free paths, stopping powers and escape depths of charged particles in condensed matter systems.

Electron impact ionization in the vicinity of comets

NASA Astrophysics Data System (ADS)

Cravens, T. E.; Kozyra, J. U.; Nagy, A. F.; Gombosi, T. I.; Kurtz, M.

1987-07-01

The solar wind interacts very strongly with the extensive cometary coma, and the various interaction processes are initiated by the ionization of cometary neutrals. The main ionization mechanism far outside the cometary bow shock is photoionization by solar extreme ultraviolet radiation.Electron distributions measured in the vicinity of comets Halley and Giacobini-Zinner by instruments on the VEGA and ICE spacecraft, respectively, are used to calculate electron impact ionization frequencies. Ionization by electrons is of comparable importance to photoionization in the magnetosheaths of Comets Halley and Giacobini-Zinner. The ionization frequency in the inner part of the cometary plasma region of comet Halley is several times greater than the photoionization value. Tables of ionization frequencies as functions of electron temperature are presented for H2O, CO2, CO, O, N2, and H.

Gate-Tunable Electron Transport Phenomena in Al-Ge⟨111⟩-Al Nanowire Heterostructures.

PubMed

Brunbauer, Florian M; Bertagnolli, Emmerich; Lugstein, Alois

2015-11-11

Electrostatically tunable negative differential resistance (NDR) is demonstrated in monolithic metal-semiconductor-metal (Al-Ge-Al) nanowire (NW) heterostructures integrated in back-gated field-effect transistors (FETs). Unambiguous signatures of NDR even at room temperature are attributed to intervalley electron transfer. At yet higher electric fields, impact ionization leads to an exponential increase of the current in the ⟨111⟩ oriented Ge NW segments. Modulation of the transfer rates, manifested as a large tunability of the peak-to-valley ratio (PVR) and the onset of impact ionization is achieved by the combined influences of electrostatic gating, geometric confinement, and heterojunction shape on hot electron transfer and by electron-electron scattering rates that can be altered by varying the charge carrier concentration in the NW FETs.

e-NEPA Guide On Registration And Preparing An EIS For Electronic Submission

EPA Pesticide Factsheets

The Guide to e-NEPA Electronic Submittal contains information about e-NEPA, how to register for e-NEPA, and how to prepare your Environmental Impact Statement (EIS) for electronic submission through e-NEPA.

Characteristics of Organic-Metal Interaction: A Perspective from Bonding Distance to Orbital Delocalization

NASA Astrophysics Data System (ADS)

Kera, Satoshi; Hosokai, Takuya; Duhm, Steffen

2018-06-01

Understanding the mechanisms of energy-level alignment and charge transfer at the interface is one of the key issues in realizing organic electronics. However, the relation between the interface structure and the electronic structure is still not resolved in sufficient detail. An important character of materials used in organic electronics is the electronic localization of organic molecules at interfaces. To elucidate the impact of the molecular orbital distribution on the electronic structure, detailed structural information is required, particularly the vertical bonding distance at the interface, which is a signature of the interaction strength. We describe the recent progress in experimental studies on the impact of the molecule-metal interaction on the electronic structure of organic-metal interfaces by using various photoelectron spectroscopies, and review the results, focusing on the X-ray standing wave technique, to demonstrate the evaluation of the vertical bonding distance.

Failure Behavior Characterization of Mo-Modified Ti Surface by Impact Test and Finite Element Analysis

NASA Astrophysics Data System (ADS)

Ma, Yong; Qin, Jianfeng; Zhang, Xiangyu; Lin, Naiming; Huang, Xiaobo; Tang, Bin

2015-07-01

Using the impact test and finite element simulation, the failure behavior of the Mo-modified layer on pure Ti was investigated. In the impact test, four loads of 100, 300, 500, and 700 N and 104 impacts were adopted. The three-dimensional residual impact dents were examined using an optical microscope (Olympus-DSX500i), indicating that the impact resistance of the Ti surface was improved. Two failure modes cohesive and wearing were elucidated by electron backscatter diffraction and energy-dispersive spectrometer performed in a field-emission scanning electron microscope. Through finite element forward analysis performed at a typical impact load of 300 N, stress-strain distributions in the Mo-modified Ti were quantitatively determined. In addition, the failure behavior of the Mo-modified layer was determined and an ideal failure model was proposed for high-load impact, based on the experimental and finite element forward analysis results.

75 FR 1568 - Endangered and Threatened Wildlife and Plants; Proposed Designation of Critical Habitat for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-12

... designation. The majority of the total future baseline impacts are associated with development projects ($6.4... development projects. The DEA estimates that total potential incremental economic impacts in areas proposed as..., the range in total incremental impacts is due to the range in development forecasts. The lack of...

Study of multipactor suppression of microwave components using perforated waveguide technology for space applications

NASA Astrophysics Data System (ADS)

Ye, Ming; Li, Yun; He, Yongning; Daneshmand, Mojgan

2017-05-01

With the development of space technology, microwave components with increased power handling capability and reduced weight have been urgently required. In this work, the perforated waveguide technology is proposed to suppress the multipactor effect of high power microwave components. Meanwhile, this novel method has the advantage of reducing components' weight, which makes it to have great potential in space applications. The perforated part of the waveguide components can be seen as an electron absorber (namely, its total electron emission yield is zero) since most of the electrons impacting on this part will go out of the components. Based on thoroughly benchmarked numerical simulation procedures, we simulated an S band and an X band waveguide transformer to conceptually verify this idea. Both electron dynamic simulations and electrical loss simulations demonstrate that the perforation technology can improve the multipactor threshold at least ˜8 dB while maintaining the acceptable insertion loss level compared with its un-perforated components. We also found that the component with larger minimum gap is easier to achieve multipactor suppression. This effect is interpreted by a parallel plate waveguide model. What's more, to improve the multipactor threshold of the X band waveguide transformer with a minimum gap of ˜0.1 mm, we proposed a perforation structure with the slope edge and explained its mechanism. Future study will focus on further optimization of the perforation structure, size, and distribution to maximize the comprehensive performances of microwave components.