Studies of Ink Trapping III Direct Detection of Small Air Bubbles in Ink Layer

Directory of Open Access Journals (Sweden)

Ikuo Naito

2006-12-01

Full Text Available Ink trappings were studied by using polyethylene terephthalate (PET film with black inks for offset proofing and synthetic paper. By observing printed matter from reverse side through the PET film, we detected many air bubbles in the ink layer and between the ink layer and the PET film. They are classified roughly to two groups, small number of large ones (φ = 2 - 5 μm and many small ones (φ = 0.5 - 1.0 μm. The former ones were fixed air bubbles during the trapping. The latter ones decreased according to increase the amount of ink trapped (y. Because number of the air bubbles (Nair bubble increased with increasing the ink distribution time, they seemed to be yielded by suspension of air into the ink layer during ink distribution. By observing printed surface, we also detected many ink peaks (immediately after the trapping and pinholes (at 24 h. The numbers of the ink peaks and pinholes (Nink peak and Npinhole, respectively decreased also with increasing the y value and increased with increasing the ink distribution time. We studied effects of nip width on these values (distribution time = 2 min.; nip width = 2, 3 and 4 mm. The Nair bubble value decreased with increasing nip width contrary to increase the Nink peak and Npinhole values. The effects can be represented by differences in the values of 2 and 4 mm nip widths. At y = 2 gm-2, the difference in the Nair bubble value is about one third (synthetic paper ink or a half (offset proofing ink of the difference in the Nink peak values.

Optical trapping of gold aerosols

DEFF Research Database (Denmark)

Schmitt, Regina K.; Pedersen, Liselotte Jauffred; Taheri, S. M.

2015-01-01

Aerosol trapping has proven challenging and was only recently demonstrated.1 This was accomplished by utilizing an air chamber designed to have a minimum of turbulence and a laser beam with a minimum of aberration. Individual gold nano-particles with diameters between 80 nm and 200 nm were trapped...... in air using a 1064 nm laser. The positions visited by the trapped gold nano-particle were quantified using a quadrant photo diode placed in the back focal plane. The time traces were analyzed and the trapping stiffness characterizing gold aerosol trapping determined and compared to aerosol trapping...... of nanometer sized silica and polystyrene particles. Based on our analysis, we concluded that gold nano-particles trap more strongly in air than similarly sized polystyrene and silica particles. We found that, in a certain power range, the trapping strength of polystyrene particles is linearly decreasing...

Multistage open-tube trap for enrichment of part-per-trillion trace components of low-pressure (below 27-kPa) air samples

Science.gov (United States)

Ohara, D.; Vo, T.; Vedder, J. F.

1985-01-01

A multistage open-tube trap for cryogenic collection of trace components in low-pressure air samples is described. The open-tube design allows higher volumetric flow rates than densely packed glass-bead traps commonly reported and is suitable for air samples at pressures below 27 kPa with liquid nitrogen as the cryogen. Gas blends containing 200 to 2500 parts per trillion by volume each of ethane and ethene were sampled and hydrocarbons were enriched with 100 + or - 4 percent trap efficiency. The multistage design is more efficient than equal-length open-tube traps under the conditions of the measurements.

Formation of Blood Foam in the Air Trap During Hemodialysis Due to Insufficient Automatic Priming of Dialyzers.

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Jonsson, Per; Lindmark, Lorentz; Axelsson, Jan; Karlsson, Lars; Lundberg, Lennart; Stegmayr, Bernd

2018-05-01

We were encouraged to investigate the reasons for large amounts of foam observed in bloodlines during hemodialysis (HD). Foam was visible in the venous air trap within the Artis Gambro dialysis device. Estimates of the extent of foam were graded (0-no foam, 10-extensive foam) by two persons that were blind to the type of dialyzer used. Thirty-seven patients were involved in the dialysis procedures. Consecutive dialyses were graded using dialyzers from Fresenius Medical Care (CorDiax dialyzers that were used for high flux HD-FX80 and FX100, and for hemodiafiltration-FX1000). The extracorporeal circuit was primed automatically by dialysate using Gambro Artis software 8.15 006 (Gambro, Dasco, Medolla Italy, Baxter, Chicago, IL, USA). The priming volume recommended by the manufacturer was 1100 mL, whereas our center uses 1500 mL. Extensive amounts of blood foam were visual in the air traps. Although the manufacturer recommended extension of priming volume up to 3000 mL, this did not eliminate the foam. Microbubble measurement during HD revealed the air to derive from the dialyzers. When changing to PF210H dialyzers (Baxter) and using a priming volume of 1500 mL, the foam was significantly less (P foam correlated with the size of the FX-dialyzer surface (P = 0.002). The auto-priming program was updated to version 8.21 by the manufacturer and the extent of foam in the air trap using FX dialyzers was now reduced and there was no longer a difference between FX and PF dialyzers, although less foam was still visible in the venous air trap during several dialyses. In conclusion, this study urgently calls attention to blood foam development in the venous air trap when using Artis devices and priming software 8.15 in combination with Fresenius dialyzers. Updated auto-priming software (version 8.21) of Artis should be requested to reduce the extent of foam for the Fresenius dialyzers. Other interactions may also be present. We recommend further studies to clarify these

Effects of cigarette smoke on methacholine- and AMP-induced air trapping in asthmatics.

Science.gov (United States)

Prieto, Luis; Palop, Julio; Llusar, Ruth; Herrera, Susana; Perez-Frances, Carmen; Lanuza, Amparo; Aguilar, Daniela

2015-02-01

Abstract Objective: No information is available on the effect of cigarette smoke on bronchoconstrictor-induced air trapping in asthma. The aim of this study was to evaluate the additional influence of smoking on methacholine- and adenosine 5'-monophosphate (AMP)-induced air trapping in subjects with asthma. Airway responsiveness to methacholine and AMP, bronchial (J'awNO) and alveolar (CANO) nitric oxide (NO) and exhaled breath condensate pH were measured in 68 adults (23 current smokers with asthma, 23 non-smokers with asthma and 22 current or former smokers with chronic obstructive pulmonary disease; COPD). The degree of air trapping induced by each bronchoconstrictor agent was expressed by the percent fall in forced vital capacity (FVC) at a 20% fall in forced expiratory volume in 1 s relative to FVC after saline inhalation (ΔFVC%). The ΔFVC% for AMP was higher in both smokers with asthma and patients with COPD than in non-smokers with asthma (p<0.001). By contrast, ΔFVC% for methacholine was similar in the three groups of subjects (p=0.69). In smokers with asthma, but not in the other two groups, there was a correlation between the residual volume/total lung capacity at baseline and the ΔFVC% induced by each bronchoconstrictor agent. Mean values for J'awNO were higher in non-smokers with asthma than in the other two groups (p<0.05). The results of this study suggest that factors underlying bronchoconstriction induced by indirect agonists are different in smokers and non-smokers with asthma. These observations might be clinically relevant, because triggers that frequently induce bronchial obstruction in the real world act by an indirect mechanism.

Air quality impacted by local pollution sources and beyond - Using a prominent petro-industrial complex as a study case.

Science.gov (United States)

Chen, Sheng-Po; Wang, Chieh-Heng; Lin, Wen-Dian; Tong, Yu-Huei; Chen, Yu-Chun; Chiu, Ching-Jui; Chiang, Hung-Chi; Fan, Chen-Lun; Wang, Jia-Lin; Chang, Julius S

2018-05-01

The present study combines high-resolution measurements at various distances from a world-class gigantic petrochemical complex with model simulations to test a method to assess industrial emissions and their effect on local air quality. Due to the complexity in wind conditions which were highly seasonal, the dominant wind flow patterns in the coastal region of interest were classified into three types, namely northeast monsoonal (NEM) flows, southwest monsoonal (SEM) flows and local circulation (LC) based on six years of monitoring data. Sulfur dioxide (SO 2 ) was chosen as an indicative pollutant for prominent industrial emissions. A high-density monitoring network of 12 air-quality stations distributed within a 20-km radius surrounding the petrochemical complex provided hourly measurements of SO 2 and wind parameters. The SO 2 emissions from major industrial sources registered by the monitoring network were then used to validate model simulations and to illustrate the transport of the SO 2 plumes under the three typical wind patterns. It was found that the coupling of observations and modeling was able to successfully explain the transport of the industrial plumes. Although the petrochemical complex was seemingly the only major source to affect local air quality, multiple prominent sources from afar also played a significant role in local air quality. As a result, we found that a more complete and balanced assessment of the local air quality can be achieved only after taking into account the wind characteristics and emission factors of a much larger spatial scale than the initial (20 km by 20 km) study domain. Copyright © 2018 Elsevier Ltd. All rights reserved.

Contribution of CT quantified emphysema, air trapping and airway wall thickness on pulmonary function in male smokers with and without COPD.

Science.gov (United States)

Mohamed Hoesein, Firdaus A A; de Jong, Pim A; Lammers, Jan-Willem J; Mali, Willem P Th M; Mets, Onno M; Schmidt, Michael; de Koning, Harry J; Aalst, Carlijn van der; Oudkerk, Matthijs; Vliegenthart, Rozemarijn; Ginneken, Bram van; van Rikxoort, Eva M; Zanen, Pieter

2014-09-01

Emphysema, airway wall thickening and air trapping are associated with chronic obstructive pulmonary disease (COPD). All three can be quantified by computed tomography (CT) of the chest. The goal of the current study is to determine the relative contribution of CT derived parameters on spirometry, lung volume and lung diffusion testing. Emphysema, airway wall thickening and air trapping were quantified automatically on CT in 1,138 male smokers with and without COPD. Emphysema was quantified by the percentage of voxels below -950 Hounsfield Units (HU), airway wall thickness by the square root of wall area for a theoretical airway with 10 mm lumen perimeter (Pi10) and air trapping by the ratio of mean lung density at expiration and inspiration (E/I-ratio). Spirometry, residual volume to total lung capacity (RV/TLC) and diffusion capacity (Kco) were obtained. Standardized regression coefficients (β) were used to analyze the relative contribution of CT changes to pulmonary function measures. The independent contribution of the three CT measures differed per lung function parameter. For the FEV1 airway wall thickness was the most contributing structural lung change (β = -0.46), while for the FEV1/FVC this was emphysema (β = -0.55). For the residual volume (RV) air trapping was most contributing (β = -0.35). Lung diffusion capacity was most influenced by emphysema (β = -0.42). In a cohort of smokers with and without COPD the effect of different CT changes varies per lung function measure and therefore emphysema, airway wall thickness and air trapping need to be taken in account.

Improving the indoor air quality by using a surface emissions trap

Science.gov (United States)

Markowicz, Pawel; Larsson, Lennart

2015-04-01

The surface emissions trap, an adsorption cloth developed for reducing emissions of volatile organic compounds and particulate matter from surfaces while allowing evaporation of moisture, was used to improve the indoor air quality of a school building with elevated air concentrations of 2-ethyl-1-hexanol. An improvement of the perceived air quality was noticed a few days after the device had been attached on the PVC flooring. In parallel, decreased air concentrations of 2-ethyl-1-hexanol were found as well as a linear increase of the amounts of the same compound adsorbed on the installed cloth as observed up to 13 months after installation. Laboratory studies revealed that the performance of the device is not affected by differences in RH (35-85%), temperature (30-40 °C) or by accelerated aging simulating up to 10 years product lifetime, and, from a blinded exposure test, that the device efficiently blocks chemical odors. This study suggests that the device may represent a fast and efficient means of restoring the indoor air quality in a building e.g. after water damage leading to irritating and potentially harmful emissions from building material surfaces indoors.

Dual-mode optical fiber-based tweezers for robust trapping and manipulation of absorbing particles in air

Science.gov (United States)

Sil, Souvik; Kanti Saha, Tushar; Kumar, Avinash; Bera, Sudipta K.; Banerjee, Ayan

2017-12-01

We develop an optical tweezers system using a single dual-mode optical fiber where mesoscopic absorbing particles can be trapped in three dimensions and manipulated employing photophoretic forces. We generate a superposition of fundamental and first order Hermite-Gaussian beam modes by the simple innovation of coupling a laser into a commercial optical fiber designed to be single mode for a wavelength higher than that of the laser. We achieve robust trapping of the absorbing particles for hours using both the pure fundamental and superposition mode beams and attain large manipulation velocities of ˜5 mm s-1 in the axial direction and ˜0.75 mm s-1 in the radial direction. We then demonstrate that the superposition mode is more effective in trapping and manipulation compared to the fundamental mode by around 80%, which may be increased several times by the use of a pure first order Hermite-Gaussian mode. The work has promising implications for trapping and spectroscopy of aerosols in air using simple optical fiber-based traps.

Effetively trapping air or lqiud water for anti-icing applications

Science.gov (United States)

Wang, Jianjun

2014-03-01

Icing on solid surfaces leads to operational difficulties and high maintenance efforts for power networks, aircrafts, ships, ground transportation vehicles and house-hold refrigerators, to name but a few. In extreme cases, icing on surfaces causes disastrous events such as crash of aircrafts and collapse of power networks, which result in severe economic impact and large loss of life. This talk is focused on the fundamentals of the ice formation and adhesion of ice with solid substrates aiming for fighting against icing on solid surfaces. When the supercooling is low, it would be possible to remove supercooled liquid water from the solid surfaces before freezing occurs. To achieve this, we design and constructed surfaces that can trap the air at the subfreezing temperature thus condensed water microdroplets could be spontaneously removed after the coalescence. When the supercooling is high, icing on surfaces occurs spontaniously. In this case, we constructed coatings on which aqueous lubricating layer could be trapped, thus the ice adhesion on the coating is so low that the ice formed atop could be removed by a wind action or its own gravity.

The effect of iterative reconstruction on computed tomography assessment of emphysema, air trapping and airway dimensions

NARCIS (Netherlands)

Mets, Onno M.; Willemink, Martin J.; de Kort, Freek P. L.; Mol, Christian P.; Leiner, Tim; Oudkerk, Matthijs; Prokop, Mathias; de Jong, Pim A.

2012-01-01

To determine the influence of iterative reconstruction (IR) on quantitative computed tomography (CT) measurements of emphysema, air trapping, and airway wall and lumen dimensions, compared to filtered back-projection (FBP). Inspiratory and expiratory chest CTs of 75 patients (37 male, 38 female;

Acoustic trapping in bubble-bounded micro-cavities

Science.gov (United States)

O'Mahoney, P.; McDougall, C.; Glynne-Jones, P.; MacDonald, M. P.

2016-12-01

We present a method for controllably producing longitudinal acoustic trapping sites inside microfluidic channels. Air bubbles are injected into a micro-capillary to create bubble-bounded `micro-cavities'. A cavity mode is formed that shows controlled longitudinal acoustic trapping between the two air/water interfaces along with the levitation to the centre of the channel that one would expect from a lower order lateral mode. 7 μm and 10 μm microspheres are trapped at the discrete acoustic trapping sites in these micro-cavities.We show this for several lengths of micro-cavity.

Investigation of enhanced cross-city transport and trapping of air pollutants by coastal and urban land-sea breeze circulations

Science.gov (United States)

Lo, Jeff C. F.; Lau, Alexis K. H.; Fung, Jimmy C. H.; Chen, Fei

2006-07-01

Recent satellite observations show that a layer of haze perpetually hangs over the Pearl River Delta (PRD) region and surface observations show numerous violations of the Hong Kong Air Quality Objective. This layer of haze mostly concentrates in the Pearl River Estuary and a narrow (20 km wide) band along the shoreline, in particular during weak wind situations. Although researchers suspect the land-sea breeze (LSB) circulations "concentrate" or "trap" various pollutants in this region, the physical mechanism of the phenomenon has never been fully explained or quantified. In this paper, a mesoscale atmospheric model (MM5) coupled with the Noah land surface model (LSM), which has bulk urban land use treatments along with a detailed Pearl River Delta land use map, is used to investigate the unique feature and mechanism of this land-sea breeze effect and the temporal evolution. A three-dimensional particle trajectory model is used to understand its associated pollutant transport, trapping and accumulation. A conceptual model is then developed for the perpetual air pollution phenomenon in the region. Further sensitivity experiments are used to illustrate the impact of urbanization and large-scale winds on the pollution processes. Results show that urbanization enhances the pollutant trapping and therefore contributes to the overall poor air quality in the region.

Quantitative assessment of global and regional air trappings using non-rigid registration and regional specific volume change of inspiratory/expiratory CT scans: Studies on healthy volunteers and asthmatics

International Nuclear Information System (INIS)

Lee, Eun Sol; Seo, Joon Beom; Lee, Hyun Joo; Chae, Eun Jin; Lee, Sang Min; Oh, Sang Young; Kim, Nam Kug

2015-01-01

The purpose of this study was to compare air trapping in healthy volunteers with asthmatics using pulmonary function test and quantitative data, such as specific volume change from paired inspiratory CT and registered expiratory CT. Sixteen healthy volunteers and 9 asthmatics underwent paired inspiratory/expiratory CT. DeltaSV, which represents the ratio of air fraction released after exhalation, was measured with paired inspiratory and anatomically registered expiratory CT scans. Air trapping indexes, DeltaSV0.4 and DeltaSV0.5, were defined as volume fraction of lung below 0.4 and 0.5 DeltaSV, respectively. To assess the gravity effect of air-trapping, DeltaSV values of anterior and posterior lung at three different levels were measured and DeltaSV ratio of anterior lung to posterior lung was calculated. Color-coded DeltaSV map of the whole lung was generated and visually assessed. Mean DeltaSV, DeltaSV0.4, and DeltaSV0.5 were compared between healthy volunteers and asthmatics. In asthmatics, correlation between air trapping indexes and clinical parameters were assessed. Mean DeltaSV, DeltaSV0.4, and DeltaSV0.5 in asthmatics were significantly higher than those in healthy volunteer group (all p < 0.05). DeltaSV values in posterior lung in asthmatics were significantly higher than those in healthy volunteer group (p = 0.049). In asthmatics, air trapping indexes, such as DeltaSV0.5 and DeltaSV0.4, showed negative strong correlation with FEF25-75, FEV1, and FEV1/FVC. DeltaSV map of asthmatics showed abnormal geographic pattern in 5 patients (55.6%) and disappearance of anterior-posterior gradient in 3 patients (33.3%). Quantitative assessment of DeltaSV (the ratio of air fraction released after exhalation) shows the difference in extent of air trapping between health volunteers and asthmatics.

Quantitative assessment of global and regional air trappings using non-rigid registration and regional specific volume change of inspiratory/expiratory CT scans: Studies on healthy volunteers and asthmatics

Energy Technology Data Exchange (ETDEWEB)

Lee, Eun Sol; Seo, Joon Beom; Lee, Hyun Joo; Chae, Eun Jin; Lee, Sang Min; Oh, Sang Young; Kim, Nam Kug [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

2015-06-15

The purpose of this study was to compare air trapping in healthy volunteers with asthmatics using pulmonary function test and quantitative data, such as specific volume change from paired inspiratory CT and registered expiratory CT. Sixteen healthy volunteers and 9 asthmatics underwent paired inspiratory/expiratory CT. DeltaSV, which represents the ratio of air fraction released after exhalation, was measured with paired inspiratory and anatomically registered expiratory CT scans. Air trapping indexes, DeltaSV0.4 and DeltaSV0.5, were defined as volume fraction of lung below 0.4 and 0.5 DeltaSV, respectively. To assess the gravity effect of air-trapping, DeltaSV values of anterior and posterior lung at three different levels were measured and DeltaSV ratio of anterior lung to posterior lung was calculated. Color-coded DeltaSV map of the whole lung was generated and visually assessed. Mean DeltaSV, DeltaSV0.4, and DeltaSV0.5 were compared between healthy volunteers and asthmatics. In asthmatics, correlation between air trapping indexes and clinical parameters were assessed. Mean DeltaSV, DeltaSV0.4, and DeltaSV0.5 in asthmatics were significantly higher than those in healthy volunteer group (all p < 0.05). DeltaSV values in posterior lung in asthmatics were significantly higher than those in healthy volunteer group (p = 0.049). In asthmatics, air trapping indexes, such as DeltaSV0.5 and DeltaSV0.4, showed negative strong correlation with FEF25-75, FEV1, and FEV1/FVC. DeltaSV map of asthmatics showed abnormal geographic pattern in 5 patients (55.6%) and disappearance of anterior-posterior gradient in 3 patients (33.3%). Quantitative assessment of DeltaSV (the ratio of air fraction released after exhalation) shows the difference in extent of air trapping between health volunteers and asthmatics.

Air trapping on chest CT is associated with worse ventilation distribution in infants with cystic fibrosis diagnosed following newborn screening.

Directory of Open Access Journals (Sweden)

Graham L Hall

Full Text Available BACKGROUND: In school-aged children with cystic fibrosis (CF structural lung damage assessed using chest CT is associated with abnormal ventilation distribution. The primary objective of this analysis was to determine the relationships between ventilation distribution outcomes and the presence and extent of structural damage as assessed by chest CT in infants and young children with CF. METHODS: Data of infants and young children with CF diagnosed following newborn screening consecutively reviewed between August 2005 and December 2009 were analysed. Ventilation distribution (lung clearance index and the first and second moment ratios [LCI, M(1/M(0 and M(2/M(0, respectively], chest CT and airway pathology from bronchoalveolar lavage were determined at diagnosis and then annually. The chest CT scans were evaluated for the presence or absence of bronchiectasis and air trapping. RESULTS: Matched lung function, chest CT and pathology outcomes were available in 49 infants (31 male with bronchiectasis and air trapping present in 13 (27% and 24 (49% infants, respectively. The presence of bronchiectasis or air trapping was associated with increased M(2/M(0 but not LCI or M(1/M(0. There was a weak, but statistically significant association between the extent of air trapping and all ventilation distribution outcomes. CONCLUSION: These findings suggest that in early CF lung disease there are weak associations between ventilation distribution and lung damage from chest CT. These finding are in contrast to those reported in older children. These findings suggest that assessments of LCI could not be used to replace a chest CT scan for the assessment of structural lung disease in the first two years of life. Further research in which both MBW and chest CT outcomes are obtained is required to assess the role of ventilation distribution in tracking the progression of lung damage in infants with CF.

Solar prominences

CERN Document Server

Engvold, Oddbjørn

2015-01-01

This volume presents the latest research results on solar prominences, including new developments on e.g. chirality, fine structure, magnetism, diagnostic tools and relevant solar plasma physics. In 1875 solar prominences, as seen out of the solar limb, were described by P.A. Secchi in his book Le Soleil as "gigantic pink or peach-flower coloured flames". The development of spectroscopy, coronagraphy and polarimetry brought tremendous observational advances in the twentieth century. The authors present and discuss exciting new challenges (resulting from observations made by space and ground-based telescopes in the 1990s and the first decade of the 21st century) concerning the diagnostics of prominences, their formation, their life time and their eruption along with their impact in the heliosphere (including the Earth). The book starts with a general introduction of the prominence “object” with some historical background on observations and instrumentation. In the next chapter, the various forms of promine...

A method for the determination of volatile ammonia in air, using a nitrogen-cooled trap and fluorometric detection

NARCIS (Netherlands)

Westra, H.G.; Tigchelaar, R.G.; Berden, J.A.

2001-01-01

A quick, cheap, and accurate method for the determination of ammonia in air is described. Ammonia and water vapor are trapped simultaneously in a gas sampling tube cooled in liquid nitrogen. Subsequently ammonia is derivatized with o-phthaldialdehyde and determined using fluorescence detection. The

Dynamic array of dark optical traps

DEFF Research Database (Denmark)

Daria, V.R.; Rodrigo, P.J.; Glückstad, J.

2004-01-01

A dynamic array of dark optical traps is generated for simultaneous trapping and arbitrary manipulation of multiple low-index microstructures. The dynamic intensity patterns forming the dark optical trap arrays are generated using a nearly loss-less phase-to-intensity conversion of a phase......-encoded coherent light source. Two-dimensional input phase distributions corresponding to the trapping patterns are encoded using a computer-programmable spatial light modulator, enabling each trap to be shaped and moved arbitrarily within the plane of observation. We demonstrate the generation of multiple dark...... optical traps for simultaneous manipulation of hollow "air-filled" glass microspheres suspended in an aqueous medium. (C) 2004 American Institute of Physics....

PROPAGATING WAVES TRANSVERSE TO THE MAGNETIC FIELD IN A SOLAR PROMINENCE

Energy Technology Data Exchange (ETDEWEB)

Schmieder, B. [Observatoire de Paris, LESIA, UMR 8109 (CNRS), F-92195 Meudon (France); Kucera, T. A.; Knizhnik, K. [Code 671, NASA' s GSFC, Greenbelt, MD 20771 (United States); Luna, M. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Lopez-Ariste, A. [THEMIS, CNRS-UPS853, E-38205 La Laguna (Spain); Toot, D. [Alfred University, Alfred, NY 14802 (United States)

2013-11-10

We report an unusual set of observations of waves in a large prominence pillar that consist of pulses propagating perpendicular to the prominence magnetic field. We observe a huge quiescent prominence with the Solar Dynamics Observatory Atmospheric Imaging Assembly in EUV on 2012 October 10 and only a part of it, the pillar, which is a foot or barb of the prominence, with the Hinode Solar Optical Telescope (SOT; in Ca II and Hα lines), Sac Peak (in Hα, Hβ, and Na-D lines), and THEMIS ({sup T}élescope Héliographique pour l' Etude du Magnétisme et des Instabilités Solaires{sup )} with the MTR (MulTi-Raies) spectropolarimeter (in He D{sub 3} line). The THEMIS/MTR data indicates that the magnetic field in the pillar is essentially horizontal and the observations in the optical domain show a large number of horizontally aligned features on a much smaller scale than the pillar as a whole. The data are consistent with a model of cool prominence plasma trapped in the dips of horizontal field lines. The SOT and Sac Peak data over the four hour observing period show vertical oscillations appearing as wave pulses. These pulses, which include a Doppler signature, move vertically, perpendicular to the field direction, along thin quasi-vertical columns in the much broader pillar. The pulses have a velocity of propagation of about 10 km s{sup –1}, a period of about 300 s, and a wavelength around 2000 km. We interpret these waves in terms of fast magnetosonic waves and discuss possible wave drivers.

Characterizing physical properties and heterogeneous chemistry of single particles in air using optical trapping-Raman spectroscopy

Science.gov (United States)

Gong, Z.; Wang, C.; Pan, Y. L.; Videen, G.

2017-12-01

Heterogeneous reactions of solid particles in a gaseous environment are of increasing interest; however, most of the heterogeneous chemistry studies of airborne solids were conducted on particle ensembles. A close examination on the heterogeneous chemistry between single particles and gaseous-environment species is the key to elucidate the fundamental mechanisms of hydroscopic growth, cloud nuclei condensation, secondary aerosol formation, etc., and reduce the uncertainty of models in radiative forcing, climate change, and atmospheric chemistry. We demonstrate an optical trapping-Raman spectroscopy (OT-RS) system to study the heterogeneous chemistry of the solid particles in air at single-particle level. Compared to other single-particle techniques, optical trapping offers a non-invasive, flexible, and stable method to isolate single solid particle from substrates. Benefited from two counter-propagating hollow beams, the optical trapping configuration is adaptive to trap a variety of particles with different materials from inorganic substitution (carbon nanotubes, silica, etc.) to organic, dye-doped polymers and bioaerosols (spores, pollen, etc.), with different optical properties from transparent to strongly absorbing, with different sizes from sub-micrometers to tens of microns, or with distinct morphologies from loosely packed nanotubes to microspheres and irregular pollen grains. The particles in the optical trap may stay unchanged, surface degraded, or optically fragmented according to different laser intensity, and their physical and chemical properties are characterized by the Raman spectra and imaging system simultaneously. The Raman spectra is able to distinguish the chemical compositions of different particles, while the synchronized imaging system can resolve their physical properties (sizes, shapes, morphologies, etc.). The temporal behavior of the trapped particles also can be monitored by the OT-RS system at an indefinite time with a resolution from

Formation and support of prominence

International Nuclear Information System (INIS)

Forbes, T.G.

1986-01-01

A short introduction is given to the concepts discussed by the group on the formation and support of prominences. Only quiescent and long-lived active region prominences were considered, since transient prominence phenomena, such as sprays, surges, H alpha flare-loops, and coronal rain, are dynamically distinct from long-lived, prominences. Stable prominences (which are often referred to as filaments when seen against the disk) can be subdivided into three categories, namely active region prominences, quiescent prominences and polar crown prominences. The third category is closely related to the second since a quiescent prominence will eventually evolve into a polar crown prominence if it lasts long enough. The distinction between the first and second categories is not sharp either since intermediates exist here as well (Martin, 1973)

ERRATUM: Propagating Waves Transverse to the Magnetic Field in a Solar Prominence

Science.gov (United States)

Schmieder, B.; Kucera, T. A.; Knizhnik, K.; Luna, M.; Lopez-Ariste, A.; Toot, D.

2014-01-01

We report an unusual set of observations of waves in a large prominence pillar that consist of pulses propagating perpendicular to the prominence magnetic field. We observe a huge quiescent prominence with the Solar Dynamics Observatory Atmospheric Imaging Assembly in EUV on 2012 October 10 and only a part of it, the pillar, which is a foot or barb of the prominence, with the Hinode Solar Optical Telescope (SOT; in Ca II and Halpha lines), Sac Peak (in Ha, Hß, and Na-D lines), and THEMIS ("Télescope Héliographique pour l' Etude du Magnétisme et des Instabilités Solaires") with the MTR (MulTi-Raies) spectropolarimeter (in He D3 line). The THEMIS/MTR data indicates that the magnetic field in the pillar is essentially horizontal and the observations in the optical domain show a large number of horizontally aligned features on a much smaller scale than the pillar as a whole. The data are consistent with a model of cool prominence plasma trapped in the dips of horizontal field lines. The SOT and Sac Peak data over the four hour observing period show vertical oscillations appearing as wave pulses. These pulses, which include a Doppler signature, move vertically, perpendicular to the field direction, along thin quasi-vertical columns in the much broader pillar. The pulses have a velocity of propagation of about 10 km/s, a period of about 300 s, and a wavelength around 2000 km. We interpret these waves in terms of fast magnetosonic waves and discuss possible wave drivers.

Air Trapping Mechanism in Artificial Salvinia-Like Micro-Hairs Fabricated via Direct Laser Lithography

Directory of Open Access Journals (Sweden)

Omar Tricinci

2017-12-01

Full Text Available Salvinia leaves represent an extraordinary example of how nature found a strategy for the long term retainment of air, and thus oxygen, on a surface, the so-called ‘Salvinia effect’, thanks to the peculiar three-dimensional and hierarchical shape of the hairs covering the leaves. Here, starting from the natural model, we have microfabricated hairs inspired by those present on the Salvinia molesta leaves, by means of direct laser lithography. Artificial hairs, like their natural counterpart, are composed of a stalk and a crown-like head, and have been reproduced in the microscale since this ensures, if using a proper design, an air-retaining behavior even if the bulk structural material is hydrophilic. We have investigated the capability of air retainment inside the heads of the hairs that can last up to 100 h, demonstrating the stability of the phenomenon. For a given dimension of the head, the greater the number of filaments, the greater the amount of air that can be trapped inside the heads since the increase in the number of solid–air interfaces able to pin the liquid phase. For this reason, such type of pattern could be used for the fabrication of surfaces for controlled gas retainment and gas release in liquid phases. The range of applications would be quite large, including industrial, medical, and biological fields.

Captures of Boll Weevils (Coleoptera: Curculionidae) in Relation to Trap Orientation and Distance From Brush Lines.

Science.gov (United States)

Spurgeon, Dale W

2016-04-01

Eradication programs for the boll weevil (Anthonomus grandis grandis Boheman) rely on pheromone-baited traps to trigger insecticide treatments and monitor program progress. A key objective of monitoring in these programs is the timely detection of incipient weevil populations to limit or prevent re-infestation. Therefore, improvements in the effectiveness of trapping would enhance efforts to achieve and maintain eradication. Association of pheromone traps with woodlots and other prominent vegetation are reported to increase captures of weevils, but the spatial scale over which this effect occurs is unknown. The influences of trap distance (0, 10, and 20 m) and orientation (leeward or windward) to brush lines on boll weevil captures were examined during three noncropping seasons (October to February) in the Rio Grande Valley of Texas. Differences in numbers of captured weevils and in the probability of capture between traps at 10 or 20 m from brush, although often statistically significant, were generally small and variable. Variations in boll weevil population levels, wind directions, and wind speeds apparently contributed to this variability. In contrast, traps closely associated with brush (0 m) generally captured larger numbers of weevils, and offered a higher probability of weevil capture compared with traps away from brush. These increases in the probability of weevil capture were as high as 30%. Such increases in the ability of traps to detect low-level boll weevil populations indicate trap placement with respect to prominent vegetation is an important consideration in maximizing the effectiveness of trap-based monitoring for the boll weevil.

Relationship between lung function and quantitative computed tomographic parameters of airway remodeling, air trapping, and emphysema in patients with asthma and chronic obstructive pulmonary disease: A single-center study.

Science.gov (United States)

Hartley, Ruth A; Barker, Bethan L; Newby, Chris; Pakkal, Mini; Baldi, Simonetta; Kajekar, Radhika; Kay, Richard; Laurencin, Marie; Marshall, Richard P; Sousa, Ana R; Parmar, Harsukh; Siddiqui, Salman; Gupta, Sumit; Brightling, Chris E

2016-05-01

There is a paucity of studies comparing asthma and chronic obstructive pulmonary disease (COPD) based on thoracic quantitative computed tomographic (QCT) parameters. We sought to compare QCT parameters of airway remodeling, air trapping, and emphysema between asthmatic patients and patients with COPD and explore their relationship with airflow limitation. Asthmatic patients (n = 171), patients with COPD (n = 81), and healthy subjects (n = 49) recruited from a single center underwent QCT and clinical characterization. Proximal airway percentage wall area (%WA) was significantly increased in asthmatic patients (62.5% [SD, 2.2]) and patients with COPD (62.7% [SD, 2.3]) compared with that in healthy control subjects (60.3% [SD, 2.2], P Emphysema assessed based on lung density measured by using Hounsfield units below which 15% of the voxels lie (Perc15) was a feature of COPD only (patients with COPD: mean, -964 [SD, 19.62] vs asthmatic patients: mean, -937 [SD, 22.7] and healthy subjects: mean, -937 [SD, 17.1], P < .001). Multiple regression analyses showed that the strongest predictor of lung function impairment in asthmatic patients was %WA, whereas in the COPD and asthma subgrouped with postbronchodilator FEV1 percent predicted value of less than 80%, it was air trapping. Factor analysis of QCT parameters in asthmatic patients and patients with COPD combined determined 3 components, with %WA, air trapping, and Perc15 values being the highest loading factors. Cluster analysis identified 3 clusters with mild, moderate, or severe lung function impairment with corresponding decreased lung density (Perc15 values) and increased air trapping. In asthmatic patients and patients with COPD, lung function impairment is strongly associated with air trapping, with a contribution from proximal airway narrowing in asthmatic patients. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Contribution of CT Quantified Emphysema, Air Trapping and Airway Wall Thickness on Pulmonary Function in Male Smokers With and Without COPD

NARCIS (Netherlands)

Hoesein, F.A.A.M.; Jong, P.A. de; Lammers, J.-W.J.; Mali, W.P.Th.; Mets, O.M.; Schmidt, M.; Koning, H.J. de; Aalst, C. van der; Oudkerk, M.; Vliegenthart, R.; Ginneken, B. van; Rikxoort, E.M. van; Zanen, P.

2014-01-01

Abstract Emphysema, airway wall thickening and air trapping are associated with chronic obstructive pulmonary disease (COPD). All three can be quantified by computed tomography (CT) of the chest. The goal of the current study is to determine the relative contribution of CT derived parameters on

Contribution of CT Quantified Emphysema, Air Trapping and Airway Wall Thickness on Pulmonary Function in Male Smokers With and Without COPD

NARCIS (Netherlands)

Hoesein, Firdaus A. A. Mohamed; de Jong, Pim A.; Lammers, Jan-Willem J.; Mali, Willem P. Th. M.; Mets, Onno M.; Schmidt, Michael; de Koning, Harry J.; van der Aalst, Carlijn; Oudkerk, Matthijs; Vliegenthart, Rozemarijn; van Ginneken, Bram; van Rikxoort, Eva M.; Zanen, Pieter

Emphysema, airway wall thickening and air trapping are associated with chronic obstructive pulmonary disease (COPD). All three can be quantified by computed tomography (CT) of the chest. The goal of the current study is to determine the relative contribution of CT derived parameters on spirometry,

Validation of the Hirst-Type Spore Trap for Simultaneous Monitoring of Prokaryotic and Eukaryotic Biodiversities in Urban Air Samples by Next-Generation Sequencing.

Science.gov (United States)

Núñez, Andrés; Amo de Paz, Guillermo; Ferencova, Zuzana; Rastrojo, Alberto; Guantes, Raúl; García, Ana M; Alcamí, Antonio; Gutiérrez-Bustillo, A Montserrat; Moreno, Diego A

2017-07-01

Pollen, fungi, and bacteria are the main microscopic biological entities present in outdoor air, causing allergy symptoms and disease transmission and having a significant role in atmosphere dynamics. Despite their relevance, a method for monitoring simultaneously these biological particles in metropolitan environments has not yet been developed. Here, we assessed the use of the Hirst-type spore trap to characterize the global airborne biota by high-throughput DNA sequencing, selecting regions of the 16S rRNA gene and internal transcribed spacer for the taxonomic assignment. We showed that aerobiological communities are well represented by this approach. The operational taxonomic units (OTUs) of two traps working synchronically compiled >87% of the total relative abundance for bacterial diversity collected in each sampler, >89% for fungi, and >97% for pollen. We found a good correspondence between traditional characterization by microscopy and genetic identification, obtaining more-accurate taxonomic assignments and detecting a greater diversity using the latter. We also demonstrated that DNA sequencing accurately detects differences in biodiversity between samples. We concluded that high-throughput DNA sequencing applied to aerobiological samples obtained with Hirst spore traps provides reliable results and can be easily implemented for monitoring prokaryotic and eukaryotic entities present in the air of urban areas. IMPORTANCE Detection, monitoring, and characterization of the wide diversity of biological entities present in the air are difficult tasks that require time and expertise in different disciplines. We have evaluated the use of the Hirst spore trap (an instrument broadly employed in aerobiological studies) to detect and identify these organisms by DNA-based analyses. Our results showed a consistent collection of DNA and a good concordance with traditional methods for identification, suggesting that these devices can be used as a tool for continuous

Apparent Solar Tornado-Like Prominences

Science.gov (United States)

Panasenco, Olga; Martin, Sara F.; Velli, Marco

2014-02-01

Recent high-resolution observations from the Solar Dynamics Observatory (SDO) have reawakened interest in the old and fascinating phenomenon of solar tornado-like prominences. This class of prominences was first introduced by Pettit ( Astrophys. J. 76, 9, 1932), who studied them over many years. Observations of tornado prominences similar to the ones seen by SDO had already been documented by Secchi ( Le Soleil, 1877). High-resolution and high-cadence multiwavelength data obtained by SDO reveal that the tornado-like appearance of these prominences is mainly an illusion due to projection effects. We discuss two different cases where prominences on the limb might appear to have a tornado-like behavior. One case of apparent vortical motions in prominence spines and barbs arises from the (mostly) 2D counterstreaming plasma motion along the prominence spine and barbs together with oscillations along individual threads. The other case of apparent rotational motion is observed in a prominence cavity and results from the 3D plasma motion along the writhed magnetic fields inside and along the prominence cavity as seen projected on the limb. Thus, the "tornado" impression results either from counterstreaming and oscillations or from the projection on the plane of the sky of plasma motion along magnetic-field lines, rather than from a true vortical motion around an (apparent) vertical or horizontal axis. We discuss the link between tornado-like prominences, filament barbs, and photospheric vortices at their base.

Mean-field model for the interference of matter-waves from a three-dimensional optical trap

International Nuclear Information System (INIS)

Adhikari, Sadhan K.; Muruganandam, Paulsamy

2003-01-01

Using the mean-field time-dependent Gross-Pitaevskii equation we study the formation of a repulsive Bose-Einstein condensate on a combined optical and harmonic traps in two and three dimensions and subsequent generation of the interference pattern upon the removal of the combined traps as in the experiment by Greiner et al. [Nature (London) 415 (2002) 39]. For optical traps of moderate strength, interference pattern of 27 (9) prominent bright spots is found to be formed in three (two) dimensions on a cubic (square) lattice in agreement with experiment. Similar interference pattern can also be formed upon removal of the optical lattice trap only. The pattern so formed can oscillate for a long time in the harmonic trap which can be observed experimentally

Performance improvement of charge-trap memory by using a stacked Zr_0_._4_6Si_0_._5_4O_2/Al_2O_3 charge-trapping layer

International Nuclear Information System (INIS)

Tang, Zhenjie; Hu, Dan; Zhang, Xiwei; Zhao, Yage; Li, Rong

2016-01-01

The postdeposition annealing (PDA)-treated charge-trap flash memory capacitor with stacked Zr_0_._4_6Si_0_._5_4O_2/Al_2O_3 charge-trapping layer flanked by a SiO_2 tunneling oxide and an Al_2O_3 blocking oxide was fabricated and investigated. It is observed that the memory capacitor exhibits prominent memory characteristics with large memory windows 12.8 V in a ±10 V gate sweeping voltage range, faster program/erase speed, and good data-retention characteristics even at 125 C compared to a single charge-trapping layer (Zr_0_._4_6Si_0_._5_4O_2, Zr_0_._7_9Si_0_._2_1O_2, and Zr_0_._4_6Al_1_._0_8O_2_._5_4). The quantum wells and introduced interfacial traps of the stacked trapping layer regulate the storage and loss behavior of charges, and jointly contribute to the improved memory characteristics. Hence, the memory capacitor with a stacked trapping layer is a promising candidate in future nonvolatile charge-trap memory device design and application. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Re-interpreting Prominences Classified as Tornadoes

Science.gov (United States)

Martin, Sara F.; Venkataramanasastry, Aparna

2015-04-01

Some papers in the recent literature identify tornado prominences with barbs of quiescent prominences while papers in the much older historic literature include a second category of tornado prominence that does not correspond to a barb of a quiescent prominence. The latter are described as prominence mass rotating around a nearly vertical axis prior to its eruption and the rotation was verified by spectral measurements. From H alpha Doppler-shifted mass motions recorded at Helio Research or the Dutch Open Telescope, we illustrate how the apparent tornado-like motions, identified with barbs, are illusions in our mind’s eye resulting from poorly resolved counterstreaming threads of mass in the barbs of quiescent prominences. In contrast, we confirm the second category of rotational motion in prominences shortly before and during eruption. In addition, we identify this second category as part of the late phase of a phenomenon called the roll effect in erupting prominences. In these cases, the eruption begins with the sideways rolling of the top of a prominence. As the eruption proceeds the rolling motion propagates down one leg or both legs of the prominence depending on whether the eruption is asymmetric or symmetric respectively. As an asymmetric eruption continues, the longer lasting leg becomes nearly vertical and its rotational motion also continues. If only this phase of the eruption was observed, as in some historic cases, it was called a tornado prominence. However, when we now observe entire eruptions in time-lapse sequences, the similarity to terrestrial tornadoes is lost. We conclude that neither prominence barbs, that give the illusion of rotation, nor the cases of true rotational motion, in the legs of erupting prominences, are usefully described as tornado prominences when the complete prominence structure or complete erupting event is observed.

Raman Spectroscopy of Optically Trapped Single Biological Micro-Particles

Science.gov (United States)

Redding, Brandon; Schwab, Mark J.; Pan, Yong-le

2015-01-01

The combination of optical trapping with Raman spectroscopy provides a powerful method for the study, characterization, and identification of biological micro-particles. In essence, optical trapping helps to overcome the limitation imposed by the relative inefficiency of the Raman scattering process. This allows Raman spectroscopy to be applied to individual biological particles in air and in liquid, providing the potential for particle identification with high specificity, longitudinal studies of changes in particle composition, and characterization of the heterogeneity of individual particles in a population. In this review, we introduce the techniques used to integrate Raman spectroscopy with optical trapping in order to study individual biological particles in liquid and air. We then provide an overview of some of the most promising applications of this technique, highlighting the unique types of measurements enabled by the combination of Raman spectroscopy with optical trapping. Finally, we present a brief discussion of future research directions in the field. PMID:26247952

Prominence mass supply and the cavity

Energy Technology Data Exchange (ETDEWEB)

Schmit, Donald J.; Innes, D. [Max Planck Institute for Solar System Research, D-37191 Katlenburg-Lindau (Germany); Gibson, S. [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO 80307 (United States); Luna, M. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Karpen, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2013-12-20

A prevalent but untested paradigm is often used to describe the prominence-cavity system: the cavity is under-dense because it is evacuated by supplying mass to the condensed prominence. The thermal non-equilibrium (TNE) model of prominence formation offers a theoretical framework to predict the thermodynamic evolution of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model with diagnostics of dynamic extreme ultraviolet (EUV) emission surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prominence plasma and coronal plasma which appear to connect the prominence and cavity. The TNE model predicts that large-scale brightenings will occur in the Solar Dynamics Observatory Atmospheric Imaging Assembly 171 Å bandpass near the prominence that are associated with the cooling phase of condensation formation. In our simulations, variations in the magnitude of footpoint heating lead to variations in the duration, spatial scale, and temporal offset between emission enhancements in the other EUV bandpasses. While these predictions match well a subset of the horn observations, the range of variations in the observed structures is not captured by the model. We discuss the implications of our one-dimensional loop simulations for the three-dimensional time-averaged equilibrium in the prominence and the cavity. Evidence suggests that horns are likely caused by condensing prominence plasma, but the larger question of whether this process produces a density-depleted cavity requires a more tightly constrained model of heating and better knowledge of the associated magnetic structure.

Investigation on de-trapping mechanisms related to non-monotonic kink pattern in GaN HEMT devices

Directory of Open Access Journals (Sweden)

Chandan Sharma

2017-08-01

Full Text Available This article reports an experimental approach to analyze the kink effect phenomenon which is usually observed during the GaN high electron mobility transistor (HEMT operation. De-trapping of charge carriers is one of the prominent reasons behind the kink effect. The commonly observed non-monotonic behavior of kink pattern is analyzed under two different device operating conditions and it is found that two different de-trapping mechanisms are responsible for a particular kink behavior. These different de-trapping mechanisms are investigated through a time delay analysis which shows the presence of traps with different time constants. Further voltage sweep and temperature analysis corroborates the finding that different de-trapping mechanisms play a role in kink behavior under different device operating conditions.

Investigation on de-trapping mechanisms related to non-monotonic kink pattern in GaN HEMT devices

Science.gov (United States)

Sharma, Chandan; Laishram, Robert; Amit, Rawal, Dipendra Singh; Vinayak, Seema; Singh, Rajendra

2017-08-01

This article reports an experimental approach to analyze the kink effect phenomenon which is usually observed during the GaN high electron mobility transistor (HEMT) operation. De-trapping of charge carriers is one of the prominent reasons behind the kink effect. The commonly observed non-monotonic behavior of kink pattern is analyzed under two different device operating conditions and it is found that two different de-trapping mechanisms are responsible for a particular kink behavior. These different de-trapping mechanisms are investigated through a time delay analysis which shows the presence of traps with different time constants. Further voltage sweep and temperature analysis corroborates the finding that different de-trapping mechanisms play a role in kink behavior under different device operating conditions.

Prominence Mass Supply and the Cavity

Science.gov (United States)

Schmit, Donald J.; Gibson, S.; Luna, M.; Karpen, J.; Innes, D.

2013-01-01

A prevalent but untested paradigm is often used to describe the prominence-cavity system; the cavity is under-dense because it it evacuated by supplying mass to the condensed prominence. The thermal non-equilibrium (TNE) model of prominence formation offers a theoretical framework to predict the thermodynamic evolutin of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model and diagnostics of dynamic extreme ultraviolet (EUV) emission surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prminence plasma and coronal plasma which appear to connect the prominence and cavity. The TNE model predicts that large-scale brightenings will occur in the Solar Dynamics Observatory Atmospheric Imaging Assembly 171 A badpass near he prominence that are associated with the cooling phase of condensation formation. In our simulations, variations in the magnitude of footpoint heating lead to variations in the duration, spatial scale, and temporal offset between emission enhancements in the other EUV bandpasses. While these predictions match well a subset of the horn observations, the range of variations in the observed structures is not captured by the model. We discuss the implications of one-dimensional loop simulations for the three-dimensional time-averaged equilibrium in the prominence and the cavity. Evidence suggests that horns are likely caused by condensing prominence plasma, but the larger question of whether this process produces a density-depleted cavity requires a more tightly constrained model of heating and better knowledge of the associated magnetic structure.

A three-dimensional model for solar prominences

International Nuclear Information System (INIS)

Demoulin, P.; Priest, E.R.; Anzer, U.

1989-01-01

Prominences have been modelled largely as one-or two-dimensional structures, and yet observations show them to possess important variations in the third dimension along the prominence axis with great arches with feet reaching down towards the solar surface. As an initial attempt to understand this structure we consider a three-dimensional linear force-free field model for the global magnetic field around a quiescent prominence. It consists of a fundamental together with a harmonic that is periodic along the prominence. At the solar surface there is a series of flux concentrations spaced out periodically on both sides of the prominence. Between a pair of oppositely directed flux concentration, the magnetic field in the prominence is stronger and tends to be less highly sheared than elsewhere. This modulation of the field strength and shear angle along the prominence decreases with height and almost disappears above 10 Mm. Prominence fields that increase with height occur when the shear is large and the length-scale for field variations perpendicular to the prominence exceeds that along it. The variation of the prominence height along the prominence is calculated and it is suggested that feet occur where the prominence sags down to low heights. For prominences of Normal polarity this tends to occur near supergranule centres where the transverse field is least, whereas for those of Inverse polarity it usually takes place near the chromospheric network where the transverse field is greatest. The effect of concentrating the base flux by including extra harmonics is also included. For Normal polarity prominences it tends to make the foot wider, and for Inverse polarity configurations, it usually creates deeper and narrower feet

QUIESCENT PROMINENCES IN THE ERA OF ALMA: SIMULATED OBSERVATIONS USING THE 3D WHOLE-PROMINENCE FINE STRUCTURE MODEL

Energy Technology Data Exchange (ETDEWEB)

Gunár, Stanislav; Heinzel, Petr [Astronomical Institute, The Czech Academy of Sciences, 25165 Ondřejov (Czech Republic); Mackay, Duncan H. [School of Mathematics and Statistics, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Anzer, Ulrich [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85740 Garching bei München (Germany)

2016-12-20

We use the detailed 3D whole-prominence fine structure model to produce the first simulated high-resolution ALMA observations of a modeled quiescent solar prominence. The maps of synthetic brightness temperature and optical thickness shown in the present paper are produced using a visualization method for synthesis of the submillimeter/millimeter radio continua. We have obtained the simulated observations of both the prominence at the limb and the filament on the disk at wavelengths covering a broad range that encompasses the full potential of ALMA. We demonstrate here extent to which the small-scale and large-scale prominence and filament structures will be visible in the ALMA observations spanning both the optically thin and thick regimes. We analyze the relationship between the brightness and kinetic temperature of the prominence plasma. We also illustrate the opportunities ALMA will provide for studying the thermal structure of the prominence plasma from the cores of the cool prominence fine structure to the prominence–corona transition region. In addition, we show that detailed 3D modeling of entire prominences with their numerous fine structures will be important for the correct interpretation of future ALMA observations of prominences.

Solar Features - Prominences and Filaments

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Prominences and filaments are two manifestations of the same phenomenon. Both prominences and filaments are features formed above the chromosphere by cool dense...

New perspectives on solar prominences

Science.gov (United States)

Schmieder, B.; Aulanier, G.

2012-06-01

Recent observations of prominences obtained with high spatial and temporal resolution instruments, on board satellites (Hinode, SDO) as well as on the ground (SST) have provided very intriguing movies and open a new area for understanding the nature of prominences. The main topics are still debate: formation, dynamics, and characteristics of the plasma in the core and in the transition zone between the prominence and corona. We will review briefly the recent advances made in these topics, observationally as well as theoretically.

Performance improvement of charge-trap memory by using a stacked Zr{sub 0.46}Si{sub 0.54}O{sub 2}/Al{sub 2}O{sub 3} charge-trapping layer

Energy Technology Data Exchange (ETDEWEB)

Tang, Zhenjie; Hu, Dan; Zhang, Xiwei; Zhao, Yage [College of Physics and Electronic Engineering, Anyang Normal University, Anyang 455000 (China); Li, Rong [School of Mathematics and Statistics, Anyang Normal University, Anyang 455000 (China)

2016-11-15

The postdeposition annealing (PDA)-treated charge-trap flash memory capacitor with stacked Zr{sub 0.46}Si{sub 0.54}O{sub 2}/Al{sub 2}O{sub 3} charge-trapping layer flanked by a SiO{sub 2} tunneling oxide and an Al{sub 2}O{sub 3} blocking oxide was fabricated and investigated. It is observed that the memory capacitor exhibits prominent memory characteristics with large memory windows 12.8 V in a ±10 V gate sweeping voltage range, faster program/erase speed, and good data-retention characteristics even at 125 C compared to a single charge-trapping layer (Zr{sub 0.46}Si{sub 0.54}O{sub 2}, Zr{sub 0.79}Si{sub 0.21}O{sub 2}, and Zr{sub 0.46}Al{sub 1.08}O{sub 2.54}). The quantum wells and introduced interfacial traps of the stacked trapping layer regulate the storage and loss behavior of charges, and jointly contribute to the improved memory characteristics. Hence, the memory capacitor with a stacked trapping layer is a promising candidate in future nonvolatile charge-trap memory device design and application. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

TANGLED MAGNETIC FIELDS IN SOLAR PROMINENCES

International Nuclear Information System (INIS)

Van Ballegooijen, A. A.; Cranmer, S. R.

2010-01-01

Solar prominences are an important tool for studying the structure and evolution of the coronal magnetic field. Here we consider so-called hedgerow prominences, which consist of thin vertical threads. We explore the possibility that such prominences are supported by tangled magnetic fields. A variety of different approaches are used. First, the dynamics of plasma within a tangled field is considered. We find that the contorted shape of the flux tubes significantly reduces the flow velocity compared to the supersonic free fall that would occur in a straight vertical tube. Second, linear force-free models of tangled fields are developed, and the elastic response of such fields to gravitational forces is considered. We demonstrate that the prominence plasma can be supported by the magnetic pressure of a tangled field that pervades not only the observed dense threads but also their local surroundings. Tangled fields with field strengths of about 10 G are able to support prominence threads with observed hydrogen density of the order of 10 11 cm -3 . Finally, we suggest that the observed vertical threads are the result of Rayleigh-Taylor instability. Simulations of the density distribution within a prominence thread indicate that the peak density is much larger than the average density. We conclude that tangled fields provide a viable mechanism for magnetic support of hedgerow prominences.

Comparative kinematical analyses of Venus flytrap (Dionaea muscipula snap traps

Directory of Open Access Journals (Sweden)

Simon Poppinga

2016-05-01

Full Text Available Although the Venus flytrap (Dionaea muscipula can be considered as one of the most extensively investigated carnivorous plants, knowledge is still scarce about diversity of the snap-trap motion, the functionality of snap traps under varying environmental conditions, and their opening motion. By conducting simple snap-trap closure experiments in air and under water, we present striking evidence that adult Dionaea snaps similarly fast in aerial and submersed states and, hence, is potentially able to gain nutrients from fast aquatic prey during seasonal inundation. We reveal three snapping modes of adult traps, all incorporating snap buckling, and show that millimeter-sized, much slower seedling traps do not yet incorporate such elastic instabilities. Moreover, opening kinematics of young and adult Dionaea snap traps reveal that reverse snap buckling is not performed, corroborating the assumption that growth takes place on certain trap lobe regions. Our findings are discussed in an evolutionary, biomechanical, functional–morphological and biomimetic context.

Magnetohydrodynamic (MHD) simulation of solar prominence formation

International Nuclear Information System (INIS)

Bao, J.

1987-01-01

Formation of Kippenhahn-Schluter type solar prominences by chromospheric mass injection is studied via numerical simulation. The numerical model is based on a two-dimensional, time-dependent magnetohydrodynamic (MHD) theory. In addition, an analysis of gravitational thermal MHD instabilities related to condensation is performed by using the small-perturbation method. The conclusions are: (1) Both quiescent and active-region prominences can be formed by chromospheric mass injection, provided certain optimum conditions are satisfied. (2) Quiescent prominences cannot be formed without condensation, though enough mass is supplied from chromosphere. The mass of a quiescent prominence is composed of both the mass injected from the chromosphere and the mass condensed from the corona. On the other hand, condensation is not important to active region prominence formation. (3) In addition to channeling and supporting effects, the magnetic field plays another important role, i.e. containing the prominence material. (4) In the model cases, prominences are supported by the Lorentz force, the gas-pressure gradient and the mass-injection momentum. (5) Due to gravity, more MHD condensation instability modes appear in addition to the basic condensation mode

Design of a high field uniformity electromagnet for Penning trap

International Nuclear Information System (INIS)

Itteera, Janvin; Singh, Kumud; Teotia, Vikas; Ukarde, Priti; Malhotra, Sanjay; Taly, Y.K.; Joshi, Manoj; Rao, Pushpa

2013-01-01

An ion trap (Penning trap) facility is being developed at BARC for spectroscopy studies. This requires the design of an iron core electromagnet capable of generating high magnetic fields (∼1.7T) at the centre of an 88 mm long air gap. This electromagnet provides the requisite dipole magnetic field which when superimposed on the electrostatic quadrupoles ensures a stable trapping of ions. To conduct high precision spectroscopy studies, we need to ensure a high degree of magnetic field uniformity ( 3 volume (Trap zone). Various pole shoe profiles were studied and modelled, FEM simulation of the same were conducted to compute the magnetic field intensity and field uniformity. Owing to the large air gap and requirement of high field intensity in the GFR, the exciting coils need to handle high current densities, which require water cooled systems. Double Pan-Cake coil design is selected for powering the magnet. Electrical, thermal and hydraulic designs of the coils are completed and a prototype double pancake coil was fabricated and tested for verifying the electrical and thermal parameter. The spatial field homogeneity is achieved by shimming the pole tip. Temporal stability of magnet requires a highly stable power supply for exciting the coils and its stability class is derived from FEM simulations. This paper discusses the electromagnetic design and development of the penning trap magnet being developed at BARC. (author)

The design and commissioning of cold trap purifying system of hydrogen meter sodium loop

International Nuclear Information System (INIS)

Zhao Zhaoyi; Jia Baoshan; Chen Xiaoming; Pan Fengguo

1993-01-01

The design feature and parameters of cold trap purifying system of hydrogen meter sodium loop and its commissioning results are reported and discussed. In order to adjust the flow easily,. the cold trap purifying system is arranged in the exit of the electromagnetic pump. It is composed of regenerator and the cold trap. The regenerator is above the cold trap. The high temperature sodium in the main-loop flows through the regenerator, in the entrance of the cold trap, its temperature is reduced to 180 degree C. After entering into the cold trap, the sodium flows to the purifying region by side, when it arrives the bottom of the trap, its temperature is reduced to 110 degree C. The cold trap is cooled by air. The temperature of the clean sodium rises nearby the main-loop's by the regenerator, and then it returns to the entrance of the electromagnetic pump. According to the commissioning results, the sodium's temperature of the cold trap could be reduced to 110 degree C by reducing the flow of the cold trap purifying system and the temperature of the main-loop, or increasing the air flow and cutting off the power supply of its heating. The authors think that the latter is more conformable with the design stipulation and with the requirement of the hydrogen meter experiment, and it can meet the requirements of the operation of the Nuclear Power Plant

Experimental quantum simulations of many-body physics with trapped ions.

Science.gov (United States)

Schneider, Ch; Porras, Diego; Schaetz, Tobias

2012-02-01

Direct experimental access to some of the most intriguing quantum phenomena is not granted due to the lack of precise control of the relevant parameters in their naturally intricate environment. Their simulation on conventional computers is impossible, since quantum behaviour arising with superposition states or entanglement is not efficiently translatable into the classical language. However, one could gain deeper insight into complex quantum dynamics by experimentally simulating the quantum behaviour of interest in another quantum system, where the relevant parameters and interactions can be controlled and robust effects detected sufficiently well. Systems of trapped ions provide unique control of both the internal (electronic) and external (motional) degrees of freedom. The mutual Coulomb interaction between the ions allows for large interaction strengths at comparatively large mutual ion distances enabling individual control and readout. Systems of trapped ions therefore exhibit a prominent system in several physical disciplines, for example, quantum information processing or metrology. Here, we will give an overview of different trapping techniques of ions as well as implementations for coherent manipulation of their quantum states and discuss the related theoretical basics. We then report on the experimental and theoretical progress in simulating quantum many-body physics with trapped ions and present current approaches for scaling up to more ions and more-dimensional systems.

Nonlinear MHD Waves in a Prominence Foot

Science.gov (United States)

Ofman, L.; Knizhnik, K.; Kucera, T.; Schmieder, B.

2015-11-01

We study nonlinear waves in a prominence foot using a 2.5D MHD model motivated by recent high-resolution observations with Hinode/Solar Optical Telescope in Ca ii emission of a prominence on 2012 October 10 showing highly dynamic small-scale motions in the prominence material. Observations of Hα intensities and of Doppler shifts show similar propagating fluctuations. However, the optically thick nature of the emission lines inhibits a unique quantitative interpretation in terms of density. Nevertheless, we find evidence of nonlinear wave activity in the prominence foot by examining the relative magnitude of the fluctuation intensity (δI/I ˜ δn/n). The waves are evident as significant density fluctuations that vary with height and apparently travel upward from the chromosphere into the prominence material with quasi-periodic fluctuations with a typical period in the range of 5-11 minutes and wavelengths <2000 km. Recent Doppler shift observations show the transverse displacement of the propagating waves. The magnetic field was measured with the THEMIS instrument and was found to be 5-14 G. For the typical prominence density the corresponding fast magnetosonic speed is ˜20 km s-1, in qualitative agreement with the propagation speed of the detected waves. The 2.5D MHD numerical model is constrained with the typical parameters of the prominence waves seen in observations. Our numerical results reproduce the nonlinear fast magnetosonic waves and provide strong support for the presence of these waves in the prominence foot. We also explore gravitational MHD oscillations of the heavy prominence foot material supported by dipped magnetic field structure.

NONLINEAR MHD WAVES IN A PROMINENCE FOOT

Energy Technology Data Exchange (ETDEWEB)

Ofman, L. [Catholic University of America, Washington, DC 20064 (United States); Knizhnik, K.; Kucera, T. [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States); Schmieder, B. [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris-Diderot, Sorbonne Paris Cit, 5 place Jules Janssen, F-92195 Meudon (France)

2015-11-10

We study nonlinear waves in a prominence foot using a 2.5D MHD model motivated by recent high-resolution observations with Hinode/Solar Optical Telescope in Ca ii emission of a prominence on 2012 October 10 showing highly dynamic small-scale motions in the prominence material. Observations of Hα intensities and of Doppler shifts show similar propagating fluctuations. However, the optically thick nature of the emission lines inhibits a unique quantitative interpretation in terms of density. Nevertheless, we find evidence of nonlinear wave activity in the prominence foot by examining the relative magnitude of the fluctuation intensity (δI/I ∼ δn/n). The waves are evident as significant density fluctuations that vary with height and apparently travel upward from the chromosphere into the prominence material with quasi-periodic fluctuations with a typical period in the range of 5–11 minutes and wavelengths <2000 km. Recent Doppler shift observations show the transverse displacement of the propagating waves. The magnetic field was measured with the THEMIS instrument and was found to be 5–14 G. For the typical prominence density the corresponding fast magnetosonic speed is ∼20 km s{sup −1}, in qualitative agreement with the propagation speed of the detected waves. The 2.5D MHD numerical model is constrained with the typical parameters of the prominence waves seen in observations. Our numerical results reproduce the nonlinear fast magnetosonic waves and provide strong support for the presence of these waves in the prominence foot. We also explore gravitational MHD oscillations of the heavy prominence foot material supported by dipped magnetic field structure.

A Simple Measure to Assess Hyperinflation and Air Trapping: 1-Forced Expiratory Volume in Three Second / Forced Vital Capacity

Directory of Open Access Journals (Sweden)

Sermin Börekçi

2017-04-01

Full Text Available Background: Several recent studies have suggested that 1 minus-forced expiratory volume expired in 3 seconds / forced vital capacity (1-FEV3/FVC may be an indicator of distal airway obstruction and a promising measure to evaluate small airways dysfunction. Aims: To investigate the associations of 1-FEV3/FVC with the spirometric measures and lung volumes that assess small airways dysfunction and reflects hyperinflation and air trapping. Study Design: Retrospective cross-sectional study. Methods: Retrospective assessment of a total of 1110 cases who underwent body plethysmographic lung volume estimations between a time span from 2005 to 2012. Patients were assigned into two groups: firstly by FEV1/FVC (FEV1/FVC <70% vs. FEV1/FVC ≥70%; secondly by FEV3/FVC < lower limits of normal (LLN (FEV3/FVC < LLN vs. FEV3/FVC ≥ LLN. Spirometric indices and lung volumes measured by whole-body plethysmography were compared in groups. Also the correlation of spirometric indices with measured lung volumes were assessed in the whole-study population and in subgroups stratified according to FEV1/FVC and FEV3/FVC. Results: Six hundred seven (54.7% were male and 503 (45.3% were female, with a mean age of 52.5±15.6 years. Mean FEV3/FVC and 1-FEV3/FVC were 87.05%, 12.95%, respectively. The mean 1-FEV3/FVC was 4.9% in the FEV1/FVC ≥70% group (n=644 vs. 24.1% in the FEV1/FVC <70% group (n=466. A positive correlation was found between 1-FEV3/FVC and residual volume (r=0.70; p<0.0001, functional residual capacity-pleth (r=0.61; p<0.0001, and total lung capacity (r=0.47; p<0.0001. 1-FEV3/FVC was negatively correlated with forced expiratory flow25-75 (r=−0.84; p<0.0001. The upper limit of 95% confidence interval for 1-FEV3/FVC was 13.7%. 1-FEV3/FVC showed significant correlations with parameters of air trapping and hyperinflation measured by whole-body plethysmography. Importantly, these correlations were higher in study participants with FEV1/FVC <70% or FEV3/FVC

Two Categories of Apparent Tornado-like Prominences

Science.gov (United States)

Martin, Sara F.; Venkataramanasastry, Aparna

2014-06-01

Two categories of solar prominences have been described in the literature as having a pattern of mass motions and/or a shape similar to terrestrial tornados. We first identify the two categories associated with prominences in the historic literature and then show that counterparts do exist for both in recent literature but one has not been called a tornado prominence. One category described as being similar to tornados is associated with the barbs of quiescent filaments but barbs appear to have rotational motion only under special conditions. H alpha Doppler observations from Helio Research confirm that this category is an illusion in our mind’s eye resulting from counterstreaming in the large barbs of quiescent filaments. The second category is a special case of rotational motion occurring during the early stages of some erupting prominences, in recent years called the roll effect in erupting prominences. In these cases, the eruption begins with the sideways rolling of the top of a prominence. As the eruption proceeds the rolling motion propagates down one leg or both legs of an erupting prominence depending on whether the eruption is asymmetric or symmetric respectively. As an asymmetric eruption proceeds, the longer lasting leg becomes nearly vertical and has true rotational motion. If only this phase of the eruption was observed, as in the historic cases, it was called a tornado prominence and spectra recorded in these cases provide proof of the rotational motion. When one observes an entire eruption which exhibits the rolling motion, as accomplished at Helio Research, the similarity to a tornado is lost because the event as a whole has quite a different nature and the analogy to a terrestrial tornado not longer appears suitable or helpful in understanding the observed and deduced physical processes. Our conclusion is that there are no solar prominences with motions that are usefully described as tornado or tornado-like events aside from the fun of observing

Sensitive and comprehensive detection of chemical warfare agents in air by atmospheric pressure chemical ionization ion trap tandem mass spectrometry with counterflow introduction.

Science.gov (United States)

Seto, Yasuo; Sekiguchi, Hiroshi; Maruko, Hisashi; Yamashiro, Shigeharu; Sano, Yasuhiro; Takayama, Yasuo; Sekioka, Ryoji; Yamaguchi, Shintaro; Kishi, Shintaro; Satoh, Takafumi; Sekiguchi, Hiroyuki; Iura, Kazumitsu; Nagashima, Hisayuki; Nagoya, Tomoki; Tsuge, Kouichiro; Ohsawa, Isaac; Okumura, Akihiko; Takada, Yasuaki; Ezawa, Naoya; Watanabe, Susumu; Hashimoto, Hiroaki

2014-05-06

A highly sensitive and specific real-time field-deployable detection technology, based on counterflow air introduction atmospheric pressure chemical ionization, has been developed for a wide range of chemical warfare agents (CWAs) comprising gaseous (two blood agents, three choking agents), volatile (six nerve gases and one precursor agent, five blister agents), and nonvolatile (three lachrymators, three vomiting agents) agents in air. The approach can afford effective chemical ionization, in both positive and negative ion modes, for ion trap multiple-stage mass spectrometry (MS(n)). The volatile and nonvolatile CWAs tested provided characteristic ions, which were fragmented into MS(3) product ions in positive and negative ion modes. Portions of the fragment ions were assigned by laboratory hybrid mass spectrometry (MS) composed of linear ion trap and high-resolution mass spectrometers. Gaseous agents were detected by MS or MS(2) in negative ion mode. The limits of detection for a 1 s measurement were typically at or below the microgram per cubic meter level except for chloropicrin (submilligram per cubic meter). Matrix effects by gasoline vapor resulted in minimal false-positive signals for all the CWAs and some signal suppression in the case of mustard gas. The moisture level did influence the measurement of the CWAs.

Automated Sampling and Extraction of Krypton from Small Air Samples for Kr-85 Measurement Using Atom Trap Trace Analysis

International Nuclear Information System (INIS)

Hebel, S.; Hands, J.; Goering, F.; Kirchner, G.; Purtschert, R.

2015-01-01

Atom-Trap-Trace-Analysis (ATTA) provides the capability of measuring the Krypton-85 concentration in microlitre amounts of krypton extracted from air samples of about 1 litre. This sample size is sufficiently small to allow for a range of applications, including on-site spot sampling and continuous sampling over periods of several hours. All samples can be easily handled and transported to an off-site laboratory for ATTA measurement, or stored and analyzed on demand. Bayesian sampling methodologies can be applied by blending samples for bulk measurement and performing in-depth analysis as required. Prerequisite for measurement is the extraction of a pure krypton fraction from the sample. This paper introduces an extraction unit able to isolate the krypton in small ambient air samples with high speed, high efficiency and in a fully automated manner using a combination of cryogenic distillation and gas chromatography. Air samples are collected using an automated smart sampler developed in-house to achieve a constant sampling rate over adjustable time periods ranging from 5 minutes to 3 hours per sample. The smart sampler can be deployed in the field and operate on battery for one week to take up to 60 air samples. This high flexibility of sampling and the fast, robust sample preparation are a valuable tool for research and the application of Kr-85 measurements to novel Safeguards procedures. (author)

Signs of helicity in solar prominences and related features

Science.gov (United States)

Martin, S.

This review illustrates several ways to identify the chirality (handedness) of solar prominences (filaments) from their structure and the structure of their surrounding magnetic fields in the chromosphere and corona. For prominences, these structural elements include the axial magnetic field direction, orientation of barbs, and direction of the prominence fine structure. The surrounding structures include the pattern of fibrils beneath the prominences and the pattern of coronal loops above the prominences. These ways of identifying chirality are then interpreted in terms of the formal definitions of helicity to yield a consistent set of one-to-one helicity relationships for all features. The helicity of some prominences can also be independently determined during their eruption by their fine structure, apparent crossings in the line-of-sight of different parts of the same prominence, and by large- scale twist of the prominence structure. Unlike observations of prominences (filaments) observed prior to eruption, in some cases evidence of both signs of helicity are found within the same erupting prominence. This indicates the continued application of forces on the prominences during the eruption process or the possible introduction of force(s) not present during earlier stages of their evolution.

Charge trapping/de-trapping in nitrided SiO2 dielectrics and its influence on device reliability

Science.gov (United States)

Kambour, Kenneth; Hjalmarson, Harold; Nguyen, Duc; Kouhestani, Camron; Devine, Roderick

2012-02-01

Field effect devices with insulator gate dielectrics are excellent test vehicles to probe the physics of defects and charge trapping in the insulator/ semiconductor structure. p-channel field effect device reliability under negative bias stressing has been identified to originate from at least two terms: a) charged defect generation at the Si substrate/SiOxNy interface and b) charge trapping at neutral defect pre-cursors in the ``bulk'' of the SiOxNy beyond the interface. Measurements of transistor characteristics enable extraction of the two terms. We report the results of such measurements and demonstrate that short time effects are associated primarily with electric field assisted tunneling of holes from the inversion layer to neutral traps. This is confirmed by bias stressing measurements at different frequencies in the range 1 Hz to 2 MHz. First principles modeling of the tunneling/trapping phenomena is presented. K.Kambour worked under contract FA9453-08-C-0245 with the Air Force Research Laboratory/RVSE. Sandia National Labs is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Optical trapping assembling of clusters and nanoparticles in solution by CW and femtosecond lasers

KAUST Repository

Masuhara, Hiroshi

2015-02-01

Laser trapping of molecular systems in solution is classified into three cases: JUST TRAPPING, EXTENDED TRAPPING, and NUCLEATION and GROWTH. The nucleation in amino acid solutions depends on where the 1064-nm CW trapping laser is focused, and crystallization and liquid–liquid phase separation are induced by laser trapping at the solution/air surface and the solution/glass interface, respectively. Laser trapping crystallization is achieved even in unsaturated solution, on which unique controls of crystallization are made possible. Crystal size is arbitrarily controlled by tuning laser power for a plate-like anhydrous crystal of l-phenylalanine. The α- or γ-crystal polymorph of glycine is selectively prepared by changing laser power and polarization. Further efficient trapping of nanoparticles and their following ejection induced by femtosecond laser pulses are introduced as unique trapping phenomena and finally future perspective is presented.

Loading an Optical Trap with Diamond Nanocrystals Containing Nitrogen-Vacancy Centers from a Surface

Science.gov (United States)

Hsu, Jen-Feng; Ji, Peng; Dutt, M. V. Gurudev; D'Urso, Brian R.

2015-03-01

We present a simple and effective method of loading particles into an optical trap. Our primary application of this method is loading photoluminescent material, such as diamond nanocrystals containing nitrogen-vacancy (NV) centers, for coupling the mechanical motion of the trapped crystal with the spin of the NV centers. Highly absorptive material at the trapping laser frequency, such as tartrazine dye, is used as media to attach nanodiamonds and burn into a cloud of air-borne particles as the material is swept near the trapping laser focus on a glass slide. Particles are then trapped with the laser used for burning or transferred to a second laser trap at a different wavelength. Evidence of successful loading diamond nanocrystals into the trap presented includes high sensitivity of the photoluminecscence (PL) to the excitation laser and the PL spectra of the optically trapped particles

Optical trapping assembling of clusters and nanoparticles in solution by CW and femtosecond lasers

KAUST Repository

Masuhara, Hiroshi; Sugiyama, Teruki; Yuyama, Kenichi; Usman, Anwar

2015-01-01

Laser trapping of molecular systems in solution is classified into three cases: JUST TRAPPING, EXTENDED TRAPPING, and NUCLEATION and GROWTH. The nucleation in amino acid solutions depends on where the 1064-nm CW trapping laser is focused, and crystallization and liquid–liquid phase separation are induced by laser trapping at the solution/air surface and the solution/glass interface, respectively. Laser trapping crystallization is achieved even in unsaturated solution, on which unique controls of crystallization are made possible. Crystal size is arbitrarily controlled by tuning laser power for a plate-like anhydrous crystal of l-phenylalanine. The α- or γ-crystal polymorph of glycine is selectively prepared by changing laser power and polarization. Further efficient trapping of nanoparticles and their following ejection induced by femtosecond laser pulses are introduced as unique trapping phenomena and finally future perspective is presented.

Quantification of prominent volatile compounds responsible for muskmelon and watermelon aroma by purge and trap extraction followed by gas chromatography-mass spectrometry determination.

Science.gov (United States)

Fredes, Alejandro; Sales, Carlos; Barreda, Mercedes; Valcárcel, Mercedes; Roselló, Salvador; Beltrán, Joaquim

2016-01-01

A dynamic headspace purge-and-trap (DHS-P&T) methodology for the determination and quantification of 61 volatile compounds responsible for muskmelon and watermelon aroma has been developed and validated. The methodology is based on the application of purge-and-trap extraction followed by gas chromatography coupled to (ion trap) mass spectrometry detection. For this purpose two different P&T sorbent cartridges have been evaluated. The influence of different extraction factors (sample weight, extraction time, and purge flow) on extraction efficiency has been studied and optimised using response surface methodology. Precision, expressed as repeatability, has been evaluated by analysing six replicates of real samples, showing relative standard deviations between 3% and 27%. Linearity has been studied in the range of 10-6130 ng mL(-1) depending on the compound response, showing coefficients of correlation between 0.995 and 0.999. Detection limits ranged between 0.1 and 274 ng g(-1). The methodology developed is well suited for analysis of large numbers of muskmelon and watermelon samples in plant breeding programs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Automated image based prominent nucleoli detection.

Science.gov (United States)

Yap, Choon K; Kalaw, Emarene M; Singh, Malay; Chong, Kian T; Giron, Danilo M; Huang, Chao-Hui; Cheng, Li; Law, Yan N; Lee, Hwee Kuan

2015-01-01

Nucleolar changes in cancer cells are one of the cytologic features important to the tumor pathologist in cancer assessments of tissue biopsies. However, inter-observer variability and the manual approach to this work hamper the accuracy of the assessment by pathologists. In this paper, we propose a computational method for prominent nucleoli pattern detection. Thirty-five hematoxylin and eosin stained images were acquired from prostate cancer, breast cancer, renal clear cell cancer and renal papillary cell cancer tissues. Prostate cancer images were used for the development of a computer-based automated prominent nucleoli pattern detector built on a cascade farm. An ensemble of approximately 1000 cascades was constructed by permuting different combinations of classifiers such as support vector machines, eXclusive component analysis, boosting, and logistic regression. The output of cascades was then combined using the RankBoost algorithm. The output of our prominent nucleoli pattern detector is a ranked set of detected image patches of patterns of prominent nucleoli. The mean number of detected prominent nucleoli patterns in the top 100 ranked detected objects was 58 in the prostate cancer dataset, 68 in the breast cancer dataset, 86 in the renal clear cell cancer dataset, and 76 in the renal papillary cell cancer dataset. The proposed cascade farm performs twice as good as the use of a single cascade proposed in the seminal paper by Viola and Jones. For comparison, a naive algorithm that randomly chooses a pixel as a nucleoli pattern would detect five correct patterns in the first 100 ranked objects. Detection of sparse nucleoli patterns in a large background of highly variable tissue patterns is a difficult challenge our method has overcome. This study developed an accurate prominent nucleoli pattern detector with the potential to be used in the clinical settings.

Automated image based prominent nucleoli detection

Directory of Open Access Journals (Sweden)

Choon K Yap

2015-01-01

Full Text Available Introduction: Nucleolar changes in cancer cells are one of the cytologic features important to the tumor pathologist in cancer assessments of tissue biopsies. However, inter-observer variability and the manual approach to this work hamper the accuracy of the assessment by pathologists. In this paper, we propose a computational method for prominent nucleoli pattern detection. Materials and Methods: Thirty-five hematoxylin and eosin stained images were acquired from prostate cancer, breast cancer, renal clear cell cancer and renal papillary cell cancer tissues. Prostate cancer images were used for the development of a computer-based automated prominent nucleoli pattern detector built on a cascade farm. An ensemble of approximately 1000 cascades was constructed by permuting different combinations of classifiers such as support vector machines, eXclusive component analysis, boosting, and logistic regression. The output of cascades was then combined using the RankBoost algorithm. The output of our prominent nucleoli pattern detector is a ranked set of detected image patches of patterns of prominent nucleoli. Results: The mean number of detected prominent nucleoli patterns in the top 100 ranked detected objects was 58 in the prostate cancer dataset, 68 in the breast cancer dataset, 86 in the renal clear cell cancer dataset, and 76 in the renal papillary cell cancer dataset. The proposed cascade farm performs twice as good as the use of a single cascade proposed in the seminal paper by Viola and Jones. For comparison, a naive algorithm that randomly chooses a pixel as a nucleoli pattern would detect five correct patterns in the first 100 ranked objects. Conclusions: Detection of sparse nucleoli patterns in a large background of highly variable tissue patterns is a difficult challenge our method has overcome. This study developed an accurate prominent nucleoli pattern detector with the potential to be used in the clinical settings.

Capillary pressure - saturation relations in quartz and carbonate sands: Limitations for correlating capillary and wettability influences on air, oil, and supercritical CO2 trapping

Science.gov (United States)

Tokunaga, T. K.; Wang, S.; Wan, J.; Dong, W.; Kim, Y.

2016-12-01

Capillary pressure (Pc) - saturation (Sw) relations are essential for predicting equilibrium and flow of immiscible fluid pairs in soils and deeper geologic formations. In systems that are difficult to measure, behavior is often estimated based on capillary scaling of easily measured Pc-Sw relations (e.g., air-water, and oil-water), yet the reliability of such approximations needs to be examined. In this study, seventeen sets of brine drainage and imbibition curves were measured with air-brine, decane-brine, and supercritical (sc) CO2-brine in homogeneous quartz and carbonate sands, using porous plate systems under ambient (0.1 MPa, 23 °C) and reservoir (12.0 MPa, 45 °C) conditions. Comparisons between these measurements showed significant differences in residual nonwetting phase saturation, Snw,r. Through applying capillary scaling, changes in interfacial properties were indicated, particularly wettability. With respect to the residual trapping of the nonwetting phases, Snwr, CO2 > Snwr, decane > Snwr, air. Decane-brine and scCO2-brine Pc-Sw curves deviated significantly from predictions assuming hydrophilic interactions. Moreover, neither the scaled capillary behavior nor Snw,r for scCO2-brine were well represented by decane-brine, apparently because of differences in wettability and viscosities, indicating limitations for using decane (and other organic liquids) as a surrogate fluid in studies intended to apply to geological carbon sequestration. Thus, challenges remain in applying scaling for predicting capillary trapping and multiphase displacement processes across such diverse fields as vadose zone hydrology, enhanced oil recovery, and geologic carbon sequestration.

Acoustic rainbow trapping by coiling up space

KAUST Repository

Ni, Xu

2014-11-13

We numerically realize the acoustic rainbow trapping effect by tapping an air waveguide with space-coiling metamaterials. Due to the high refractive-index of the space-coiling metamaterials, our device is more compact compared to the reported trapped-rainbow devices. A numerical model utilizing effective parameters is also calculated, whose results are consistent well with the direct numerical simulation of space-coiling structure. Moreover, such device with the capability of dropping different frequency components of a broadband incident temporal acoustic signal into different channels can function as an acoustic wavelength division de-multiplexer. These results may have potential applications in acoustic device design such as an acoustic filter and an artificial cochlea.

Acoustic rainbow trapping by coiling up space

KAUST Repository

Ni, Xu; Wu, Ying; Chen, Ze-Guo; Zheng, Li-Yang; Xu, Ye-Long; Nayar, Priyanka; Liu, Xiao-Ping; Lu, Ming-Hui; Chen, Yan-Feng

2014-01-01

We numerically realize the acoustic rainbow trapping effect by tapping an air waveguide with space-coiling metamaterials. Due to the high refractive-index of the space-coiling metamaterials, our device is more compact compared to the reported trapped-rainbow devices. A numerical model utilizing effective parameters is also calculated, whose results are consistent well with the direct numerical simulation of space-coiling structure. Moreover, such device with the capability of dropping different frequency components of a broadband incident temporal acoustic signal into different channels can function as an acoustic wavelength division de-multiplexer. These results may have potential applications in acoustic device design such as an acoustic filter and an artificial cochlea.

Assessment of regional emphysema, air-trapping and Xenon-ventilation using dual-energy computed tomography in chronic obstructive pulmonary disease patients.

Science.gov (United States)

Lee, Sang Min; Seo, Joon Beom; Hwang, Hye Jeon; Kim, Namkug; Oh, Sang Young; Lee, Jae Seung; Lee, Sei Won; Oh, Yeon-Mok; Kim, Tae Hoon

2017-07-01

To compare the parenchymal attenuation change between inspiration/expiration CTs with dynamic ventilation change between xenon wash-in (WI) inspiration and wash-out (WO) expiration CTs. 52 prospectively enrolled COPD patients underwent xenon ventilation dual-energy CT during WI and WO periods and pulmonary function tests (PFTs). The parenchymal attenuation parameters (emphysema index (EI), gas-trapping index (GTI) and air-trapping index (ATI)) and xenon ventilation parameters (xenon in WI (Xe-WI), xenon in WO (Xe-WO) and xenon dynamic (Xe-Dyna)) of whole lung and three divided areas (emphysema, hyperinflation and normal) were calculated on virtual non-contrast images and ventilation images. Pearson correlation, linear regression analysis and one-way ANOVA were performed. EI, GTI and ATI showed a significant correlation with Xe-WI, Xe-WO and Xe-Dyna (EI R = -.744, -.562, -.737; GTI R = -.621, -.442, -.629; ATI R = -.600, -.421, -.610, respectively, p emphysema. • The xenon ventilation change correlates with the parenchymal attenuation change. • The xenon ventilation change shows the difference between three lung areas. • The combination of attenuation and xenon can predict more accurate PFTs.

Combustion of alternative fuels in vortex trapped combustor

International Nuclear Information System (INIS)

Ghenai, Chaouki; Zbeeb, Khaled; Janajreh, Isam

2013-01-01

Highlights: ► We model the combustion of alternative fuels in trapped vortex combustor (TVC). ► We test syngas and hydrogen/hydrocarbon mixture fuels. ► We examine the change in combustion performance and emissions of TVC combustor. ► Increasing the hydrogen content of the fuel will increase the temperature and NO x emissions. ► A high combustor efficiency is obtained for fuels with different compositions and LHV. - Abstract: Trapped vortex combustor represents an efficient and compact combustor for flame stability. Combustion stability is achieved through the use of cavities in which recirculation zones of hot products generated by the direct injection of fuel and air are created and acting as a continuous source of ignition for the incoming main fuel–air stream. Computational Fluid Dynamics analysis was performed in this study to test the combustion performance and emissions from the vortex trapped combustor when natural gas fuel (methane) is replaced with renewable and alternative fuels such as hydrogen and synthetic gas (syngas). The flame temperature, the flow field, and species concentrations inside the Vortex Trapped Combustor were obtained. The results show that hydrogen enriched hydrocarbon fuels combustion will result in more energy, higher temperature (14% increase when methane is replaced with hydrogen fuels) and NO x emissions, and lower CO 2 emissions (50% decrease when methane is replaced with methane/hydrogen mixture with 75% hydrogen fraction). The NO x emission increases when the fraction of hydrogen increases for methane/hydrogen fuel mixture. The results also show that the flame for methane combustion fuel is located in the primary vortex region but it is shifted to the secondary vortex region for hydrogen combustion.

A simple trapping method of exhaled water using an ice-cooled tube to monitor the tritium level in human body

International Nuclear Information System (INIS)

Nogawa, Norio; Makide, Yoshihiro

1994-01-01

A convenient and efficient method is developed for the trapping of water in exhaled air. A bent-V-shaped glass sampling tube was immersed in iced water and exhaled air was introduced into the tube through a plastic straw. The trapping efficiency of exhaled water was equivalent to those with more complex and troublesome methods. Using anywhere available ice, the water in exhaled air can be rapidly collected with this method and the tritium level in the body will be quickly obtained. (author)

Topic prominence in Chinese EFL learners’ interlanguage

Directory of Open Access Journals (Sweden)

Shaopeng Li

2014-01-01

Full Text Available The present study aims to investigate the general characteristics of topicprominent typological interlanguage development of Chinese learners of English in terms of acquiring subject-prominent English structures from a discourse perspective. Topic structures mainly appear in Chinese discourse in the form of topic chains (Wang, 2002; 2004. The research target are the topic chain, which is the main topic-prominent structure in Chinese discourse, and zero anaphora, which is the most common topic anaphora in the topic chain. Two important findings emerged from the present study. First, the characteristics of Chinese topic chains are transferrable to the interlanguage of Chinese EFL learners, thus resulting in overgeneralization of the zero anaphora. Second, the interlanguage discourse of Chinese EFL learners reflects a change of the second language acquisition process from topic-prominence to subject-prominence, thus lending support to the discourse transfer hypothesis.

EUV observations of quiescent prominences from Skylab

International Nuclear Information System (INIS)

Moe, O.K.

1979-01-01

The authors report measurements of line intensities and line widths for three quiescent prominences observed with the Naval Research Laboratory slit spectrograph on ATM/Skylab. The wavelengths of the observed lines cover the range 1175 A to 1960 A. The measured intensities have been calibrated to within approximately a factor 2 and are average intensities over a 2 arc sec by 60 arc set slit. Nonthermal velocities are derived from the measured line widths. The nonthermal velocity is found to increase with temperature in the prominence transition zone. Electron densities and pressures are derived from density sensitive line ratios. Electron pressures for two of the prominences are found to lie in the range 0.04-0.08 dyn cm -2 , while values for the third and most intense and active of the three prominences are in the range 0.07-0.22 dyn cm -2 . (Auth.)

Adaptation of the continuous cold-trap system of fluidized-bed to the fluoride volatility process

International Nuclear Information System (INIS)

1976-01-01

A continuous cold-trap system consisting of fluidized condensor and stripper has been evaluated with a view to adapt it to the Fluoride Volatility Process in establishing the continuous purification process without radiation decomposition of PuF 6 . Its feasibility is shown by the test with UF 6 -air. Necessary conditions for the cold trap, and performance of the 2-in.-dia. fluidized-bed cold-trap system are presented, and also a model of mist formation in the condensor

Multispacecraft observations of a prominence eruption

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A. Bemporad

2009-10-01

Full Text Available On 9 May 2007 a prominence eruption occurred at the West limb. Remarkably, the event was observed by the STEREO/EUVI telescopes and by the HINODE/EIS and SOHO/UVCS spectrometers. We present results from all these instruments. High-cadence (~37 s data from STEREO/EUVI A and B in the He II λ304 line were used to study the 3-D shape and expansion of the prominence. The high spatial resolution EUVI images (~1.5"/pixel have been used to infer via triangulation the 3-D shape and orientation of the prominence 12 min after the eruption onset. At this time the prominence has mainly the shape of a "hook" highly inclined southward, has an average thickness of 0.068 R⊙, a length of 0.43 R⊙ and lies, in first approximation, on a plane. Hence, the prominence is mainly a 2-D structure and there is no evidence for a twisted flux rope configuration. HINODE/EIS was scanning with the 2" slit the region where the filament erupted. The EIS spectra show during the eruption remarkable non-thermal broadening (up to ~100 km s−1 in the region crossed by the filament in spectral lines emitted at different temperatures, possibly with differences among lines from higher Fe ionization stages. The CME was also observed by the SOHO/UVCS instrument: the spectrograph slit was centered at 1.7 R⊙, at a latitude of 5° SW and recorded a sudden increase in the O VI λλ1032–1037 and Si XII λ520 spectral line intensities, representative of the CME front transit.

Static current-sheet models of quiescent prominences

Science.gov (United States)

Wu, F.; Low, B. C.

1986-12-01

A particular class of theoretical models idealize the prominence to be a discrete flat electric-current sheet suspended vertically in a potential magnetic field. The weight of the prominence is supported by the Lorentz force in the current sheet. These models can be extended to have curved electric-current sheets and to vary three-dimensionally. The equation for force balance is 1 over 4 pi (del times B) times Bdel p- p9 z=zero. Using Cartesian coordinates we take, for simplicity, a uniform gravity with constant acceleration g in the direction -z. If we are interested not in the detailed internal structure of the prominence, but in the global magnetic configuration around the prominence, we may take prominence plasma to be cold. Consideration is given to how such equilibrium states can be constructed. To simplify the mathematical problem, suppose there is no electric current in the atmosphere except for the discrete currents in the cold prominence sheet. Let us take the plane z =0 to be the base of the atmosphere and restrict our attention to the domain z greater than 0. The task we have is to solve for a magnetic field which is everywhere potential except on some free surface S, subject to suit able to boundary conditions. The surface S is determined by requiring that it possesses a discrete electric current density such that the Lorentz force on it is everywhere vertically upward to balance the weight of the material m(S). Since the magnetic field is potential in the external atmosphere, the latter is decoupled from the magnetic field and its plane parallel hydrostatic pressure and density can be prescribed.

Adaptation of the continuous cold trap system of fluidized-bed to the fluoride volatility process

International Nuclear Information System (INIS)

1976-02-01

A continuous cold trap system consisting of fluidized condenser and stripper has been evaluated with a view to adapt it to the Fluoride Volatility Process in establishing the continuous purification process without radiation decomposition of PuF 6 . Its feasibility is shown by the test with UF 6 -air. Necessary conditions for the cold trap, and performance of the two inch-dia. fluidized bed cold trap system are presented, and also a model of mist formation in the condenser. (auth.)

Neutral Atom Diffusion in a Partially Ionized Prominence Plasma

Science.gov (United States)

Gilbert, Holly

2010-01-01

The support of solar prominences is normally described in terms of a magnetic force on the prominence plasma that balances the solar gravitational force. Because the prominence plasma is only partially ionized. it is necessary to consider in addition the support of the neutral component of the prominence plasma. This support is accomplished through a frictional interaction between the neutral and ionized components of the plasma, and its efficacy depends strongly on the degree of ionization of the plasma. More specifically, the frictional force is proportional to the relative flow of neutral and ion species, and for a sufficiently weakly ionized plasma, this flow must be relatively large to produce a frictional force that balances gravity. A large relative flow, of course, implies significant draining of neutral particles from the prominence. We evaluate the importance of this draining effect for a hydrogen-helium plasma, and consider the observational evidence for cross-field diffusion of neutral prominence material,

Guide to Air Cleaners in the Home

Science.gov (United States)

... as electrostatic precipitators use a process called electrostatic attraction to trap charged particles. They draw air through ... of ozone with indoor chemicals such as those coming from household cleaning products, air fresheners, certain paints, ...

Assessment of regional emphysema, air-trapping and Xenon-ventilation using dual-energy computed tomography in chronic obstructive pulmonary disease patients

International Nuclear Information System (INIS)

Lee, Sang Min; Seo, Joon Beom; Kim, Namkug; Oh, Sang Young; Hwang, Hye Jeon; Lee, Jae Seung; Lee, Sei Won; Oh, Yeon-Mok; Kim, Tae Hoon

2017-01-01

To compare the parenchymal attenuation change between inspiration/expiration CTs with dynamic ventilation change between xenon wash-in (WI) inspiration and wash-out (WO) expiration CTs. 52 prospectively enrolled COPD patients underwent xenon ventilation dual-energy CT during WI and WO periods and pulmonary function tests (PFTs). The parenchymal attenuation parameters (emphysema index (EI), gas-trapping index (GTI) and air-trapping index (ATI)) and xenon ventilation parameters (xenon in WI (Xe-WI), xenon in WO (Xe-WO) and xenon dynamic (Xe-Dyna)) of whole lung and three divided areas (emphysema, hyperinflation and normal) were calculated on virtual non-contrast images and ventilation images. Pearson correlation, linear regression analysis and one-way ANOVA were performed. EI, GTI and ATI showed a significant correlation with Xe-WI, Xe-WO and Xe-Dyna (EI R = -.744, -.562, -.737; GTI R = -.621, -.442, -.629; ATI R = -.600, -.421, -.610, respectively, p < 0.01). All CT parameters showed significant correlation with PFTs except forced vital capacity (FVC). There was a significant difference in GTI, ATI and Xe-Dyna in each lung area (p < 0.01). The parenchymal attenuation change between inspiration/expiration CTs and xenon dynamic change between xenon WI- and WO-CTs correlate significantly. There are alterations in the dynamics of xenon ventilation between areas of emphysema. (orig.)

Assessment of regional emphysema, air-trapping and Xenon-ventilation using dual-energy computed tomography in chronic obstructive pulmonary disease patients

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang Min [University of Ulsan College of Medicine, Division of Cardiothoracic Radiology, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Yonsei University College of Medicine, Gangnam Severance Hospital, Department of Radiology, Research Istitute of Radiological Science, Seoul (Korea, Republic of); Seo, Joon Beom; Kim, Namkug; Oh, Sang Young [University of Ulsan College of Medicine, Division of Cardiothoracic Radiology, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Hwang, Hye Jeon [University of Ulsan College of Medicine, Division of Cardiothoracic Radiology, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Hallym University Sacred Heart Hospital, Department of Radiology, Hallym University College of Medicine, Anyang-si, Gyeonggi-do (Korea, Republic of); Lee, Jae Seung; Lee, Sei Won; Oh, Yeon-Mok [University of Ulsan College of Medicine, Department of Pulmonary and Critical Care Medicine, and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, Seoul (Korea, Republic of); Kim, Tae Hoon [Yonsei University College of Medicine, Gangnam Severance Hospital, Department of Radiology, Research Istitute of Radiological Science, Seoul (Korea, Republic of)

2017-07-15

To compare the parenchymal attenuation change between inspiration/expiration CTs with dynamic ventilation change between xenon wash-in (WI) inspiration and wash-out (WO) expiration CTs. 52 prospectively enrolled COPD patients underwent xenon ventilation dual-energy CT during WI and WO periods and pulmonary function tests (PFTs). The parenchymal attenuation parameters (emphysema index (EI), gas-trapping index (GTI) and air-trapping index (ATI)) and xenon ventilation parameters (xenon in WI (Xe-WI), xenon in WO (Xe-WO) and xenon dynamic (Xe-Dyna)) of whole lung and three divided areas (emphysema, hyperinflation and normal) were calculated on virtual non-contrast images and ventilation images. Pearson correlation, linear regression analysis and one-way ANOVA were performed. EI, GTI and ATI showed a significant correlation with Xe-WI, Xe-WO and Xe-Dyna (EI R = -.744, -.562, -.737; GTI R = -.621, -.442, -.629; ATI R = -.600, -.421, -.610, respectively, p < 0.01). All CT parameters showed significant correlation with PFTs except forced vital capacity (FVC). There was a significant difference in GTI, ATI and Xe-Dyna in each lung area (p < 0.01). The parenchymal attenuation change between inspiration/expiration CTs and xenon dynamic change between xenon WI- and WO-CTs correlate significantly. There are alterations in the dynamics of xenon ventilation between areas of emphysema. (orig.)

TORNADO-LIKE EVOLUTION OF A KINK-UNSTABLE SOLAR PROMINENCE

Energy Technology Data Exchange (ETDEWEB)

Wang, Wensi; Liu, Rui; Wang, Yuming, E-mail: rliu@ustc.edu.cn [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei 230026 (China)

2017-01-01

We report on the tornado-like evolution of a quiescent prominence on 2014 November 1. The eastern section of the prominence first rose slowly, transforming into an arch-shaped structure as high as ∼150 Mm above the limb; the arch then writhed moderately in a left-handed sense, while the original dark prominence material emitted in the Fe ix 171 Å passband, and a braided structure appeared at the eastern edge of the warped arch. The unraveling of the braided structure was associated with a transient brightening in the EUV and apparently contributed to the formation of a curtain-like structure (CLS). The CLS consisted of myriad thread-like loops rotating counterclockwise about the vertical if viewed from above. Heated prominence material was observed to slide along these loops and land outside the filament channel. The tornado eventually disintegrated and the remaining material flew along a left-handed helical path constituting approximately a full turn, as corroborated through stereoscopic reconstruction, into the cavity of the stable, western section of the prominence. We suggest that the tornado-like evolution of the prominence was governed by the helical kink instability, and that the CLS formed through magnetic reconnections between the prominence field and the overlying coronal field.

Volume traps - a new retrospective radon monitor

International Nuclear Information System (INIS)

Oberstedt, S.; Vanmarcke, H.

1994-11-01

A new method to trace back average radon concentrations in dwellings over several decades in time has been developed. This retrospective radon monitor is based on the measurement of the alpha activity of 210 Po deposited in volume traps, for example spongy materials used for mattresses and cushions. Polyester samples with different densities have been exposed to radon-laden air. The exposures correspond to characteristic radon concentrations between 390 Bq/m 3 and 3.9 Bq/m 3 over a 20 years period. The precision in converting the 210 Po signal to the radon exposure has been improved by more than one order of magnitude compared to other common techniques. It is shown that this very sensitive method may be applied to almost all types of volume traps used in households

Poling effect of a charge-trapping layer in glass waveguides

DEFF Research Database (Denmark)

Ren, Yitao; Marckmann, Carl Johan; Jacobsen, Rune Shim

2004-01-01

Germanium-doped multi-layer waveguides containing a silicon oxy-nitride layer as a charge trapper are thermally poled in an air environment. Compared to the waveguides without the trapping layer, the induced linear electro-optic coefficient increases more than 20%. A comparable rise in the intern...

Solar Tornado Prominences: Plasma Motions Along Filament Barbs

Science.gov (United States)

Panasenco, Olga; Velli, Marco; Martin, Sara F.; Rappazzo, Franco

2013-03-01

Recent high-resolution observations from the Solar Dynamic Observatory (SDO) have reawakened interest in the old and fascinating phenomenon of solar tornado prominences. This class of prominences was first introduced by E. Pettit in 1932, who studied them over many years up to 1950. High resolution and high cadence multi-wavelength data obtained by SDO reveal that the tornado-like properties of these prominences are mainly an illusion due to projection effects. We show that counterstreaming plasma motions with projected velocities up to +/- 45 km/sec along the prominence spine and barbs create a tornado-like impression when viewed at the limb. We demonstrate that barbs are often rooted at the intersection between 4-5 supergranular cells. We discuss the observed oscillations along the vertical parts of barbs and whether they may be related to vortex flows coming from the convection downdrafts at the intersection of supergranules (and possibly smaller convective cells) in the photosphere and their entrained magnetic field. The unwinding of magnetic threads near the photosphere via reconnection might be a source of the waves which are observed as oscillations in prominence barbs.

MAGNETIC FIELD IN ATYPICAL PROMINENCE STRUCTURES: BUBBLE, TORNADO, AND ERUPTION

Energy Technology Data Exchange (ETDEWEB)

Levens, P. J.; Labrosse, N. [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Schmieder, B. [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, F-92195 Meudon (France); López Ariste, A. [IRAP—CNRS UMR 5277, 14, Av. E. Belin, F-31400 Toulouse (France); Dalmasse, K. [CISL/HAO, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307-3000 (United States); Gelly, B., E-mail: p.levens.1@research.gla.ac.uk, E-mail: brigitte.schmieder@obspm.fr [CNRS UMR 3718 THEMIS, La Laguna, Tenerife (Spain)

2016-08-01

Spectropolarimetric observations of prominences have been obtained with the THEMIS telescope during four years of coordinated campaigns. Our aim is now to understand the conditions of the cool plasma and magnetism in “atypical” prominences, namely when the measured inclination of the magnetic field departs, to some extent, from the predominantly horizontal field found in “typical” prominences. What is the role of the magnetic field in these prominence types? Are plasma dynamics more important in these cases than the magnetic support? We focus our study on three types of “atypical” prominences (tornadoes, bubbles, and jet-like prominence eruptions) that have all been observed by THEMIS in the He i D{sub 3} line, from which the Stokes parameters can be derived. The magnetic field strength, inclination, and azimuth in each pixel are obtained by using the inversion method of principal component analysis on a model of single scattering in the presence of the Hanle effect. The magnetic field in tornadoes is found to be more or less horizontal, whereas for the eruptive prominence it is mostly vertical. We estimate a tendency toward higher values of magnetic field strength inside the bubbles than outside in the surrounding prominence. In all of the models in our database, only one magnetic field orientation is considered for each pixel. While sufficient for most of the main prominence body, this assumption appears to be oversimplified in atypical prominence structures. We should consider these observations as the result of superposition of multiple magnetic fields, possibly even with a turbulent field component.

Potential Use of Spin Traps to Control ROS in Antipollution Cosmetics—A Review

Directory of Open Access Journals (Sweden)

Prashant D. Sawant

2018-01-01

Full Text Available Pollution from air and sunlight has adverse effects on human health, particularly skin health. It creates oxidative stress, which results in skin diseases, including skin cancer and aging. Different types of antioxidants are used as preventative actives in skin-care products. However, they have some limitations as they also scavenge oxygen. Recently, spin traps are being explored to trap free radicals before these radicals generating more free radicals (cascading effect and not the oxygen molecules. However, not all spin traps can be used in the topical cosmetic skin-care products due to their toxicity and regulatory issues. The present review focuses on the different pathways of reactive oxygen species (ROS generation due to pollution and the potential use of spin traps in anti-pollution cosmetics to control ROS.

An assessment of hopanes in settled dust and air as indicators of exposure to traffic-related air pollution in Windsor, Ontario

Science.gov (United States)

Curran, Jason

Traffic-related air pollution (TRAP) has been linked with several adverse health effects. We investigated hopanes, markers of primary particle emissions from gasoline and diesel engines, in house dust as an alternative approach for assessing exposure to TRAP in Windsor, Ontario. Settled house dust was collected from the homes of 28 study participants (10 -- 13 yrs). The dust was then analyzed for a suite of hopanes by gas chromatography-mass spectrometry. We calculated correlations between dust hopane concentrations and estimates of annual average NO2 concentrations derived from an existing LUR model. Hopanes were consistently present in detectable quantities in house dust. Annual average outdoor NO2 estimated was moderately correlated with hopanes in house dust (r = 0.46; pefficiency or the presence of an attached garage. Hopanes measured in settled house dust show promise as an indicator of long-term exposure to traffic-related air pollution. Keywords: hopane; air pollution; traffic; dust; exposure; TRAP.

The Computational Processing of Intonational Prominence: A Functional Prosody Perspective

OpenAIRE

Nakatani, Christine Hisayo

1997-01-01

Intonational prominence, or accent, is a fundamental prosodic feature that is said to contribute to discourse meaning. This thesis outlines a new, computational theory of the discourse interpretation of prominence, from a FUNCTIONAL PROSODY perspective. Functional prosody makes the following two important assumptions: first, there is an aspect of prominence interpretation that centrally concerns discourse processes, namely the discourse focusing nature of prominence; and second, the role of p...

Optical trapping and Raman spectroscopy of solid particles.

Science.gov (United States)

Rkiouak, L; Tang, M J; Camp, J C J; McGregor, J; Watson, I M; Cox, R A; Kalberer, M; Ward, A D; Pope, F D

2014-06-21

The heterogeneous interactions of gas molecules on solid particles are crucial in many areas of science, engineering and technology. Such interactions play a critical role in atmospheric chemistry and in heterogeneous catalysis, a key technology in the energy and chemical industries. Investigating heterogeneous interactions upon single levitated particles can provide significant insight into these important processes. Various methodologies exist for levitating micron sized particles including: optical, electrical and acoustic techniques. Prior to this study, the optical levitation of solid micron scale particles has proved difficult to achieve over timescales relevant to the above applications. In this work, a new vertically configured counter propagating dual beam optical trap was optimized to levitate a range of solid particles in air. Silica (SiO2), α-alumina (Al2O3), titania (TiO2) and polystyrene were stably trapped with a high trapping efficiency (Q = 0.42). The longest stable trapping experiment was conducted continuously for 24 hours, and there are no obvious constraints on trapping time beyond this period. Therefore, the methodology described in this paper should be of major benefit to various research communities. The strength of the new technique is demonstrated by the simultaneous levitation and spectroscopic interrogation of silica particles by Raman spectroscopy. In particular, the adsorption of water upon silica was investigated under controlled relative humidity environments. Furthermore, the collision and coagulation behaviour of silica particles with microdroplets of sulphuric acid was followed using both optical imaging and Raman spectroscopy.

Effects of oxide traps, interface traps, and ''border traps'' on metal-oxide-semiconductor devices

International Nuclear Information System (INIS)

Fleetwood, D.M.; Winokur, P.S.; Reber, R.A. Jr.; Meisenheimer, T.L.; Schwank, J.R.; Shaneyfelt, M.R.; Riewe, L.C.

1993-01-01

We have identified several features of the 1/f noise and radiation response of metal-oxide-semiconductor (MOS) devices that are difficult to explain with standard defect models. To address this issue, and in response to ambiguities in the literature, we have developed a revised nomenclature for defects in MOS devices that clearly distinguishes the language used to describe the physical location of defects from that used to describe their electrical response. In this nomenclature, ''oxide traps'' are simply defects in the SiO 2 layer of the MOS structure, and ''interface traps'' are defects at the Si/SiO 2 interface. Nothing is presumed about how either type of defect communicates with the underlying Si. Electrically, ''fixed states'' are defined as trap levels that do not communicate with the Si on the time scale of the measurements, but ''switching states'' can exchange charge with the Si. Fixed states presumably are oxide traps in most types of measurements, but switching states can either be interface traps or near-interfacial oxide traps that can communicate with the Si, i.e., ''border traps'' [D. M. Fleetwood, IEEE Trans. Nucl. Sci. NS-39, 269 (1992)]. The effective density of border traps depends on the time scale and bias conditions of the measurements. We show the revised nomenclature can provide focus to discussions of the buildup and annealing of radiation-induced charge in non-radiation-hardened MOS transistors, and to changes in the 1/f noise of MOS devices through irradiation and elevated-temperature annealing

A new quantitative index of lobar air trapping in chronic obstructive pulmonary disease (COPD): Comparison with conventional methods

Energy Technology Data Exchange (ETDEWEB)

Nagatani, Yukihiro, E-mail: yatsushi@belle.shiga-med.ac.jp [Department of Radiology, Shiga University of Medical Science, Seta-tsukinowa-cho, Otsu, Shiga 520-2192 (Japan); Murata, Kiyoshi; Takahashi, Masashi; Nitta, Norihisa [Department of Radiology, Shiga University of Medical Science, Seta-tsukinowa-cho, Otsu, Shiga 520-2192 (Japan); Nakano, Yasutaka [Division of Respiratory Medicine, Department of Internal Medicine, Shiga University of Medical Science, Seta-tsukinowa-cho, Otsu, Shiga 520-2192 (Japan); Sonoda, Akinaga; Otani, Hideji [Department of Radiology, Shiga University of Medical Science, Seta-tsukinowa-cho, Otsu, Shiga 520-2192 (Japan); Okabe, Hidetoshi [Department of Clinical Laboratory, Shiga University of Medical Science, Seta-tsukinowa-cho, Otsu, Shiga 520-2192 (Japan); Ogawa, Emiko [Health Administration Center, Shiga University of Medical Science, Seta-tsukinowa-cho, Otsu, Shiga 520-2192 (Japan)

2015-05-15

Highlights: • In the total lung field, AVI had excellent correlation with FEV{sub 1}/FVC. • AVI showed differences between three groups classified by the COPD severity. • In a lobe-based analysis, AVI did not mostly correlated with volume decrease ratio. • In a lobe-based analysis, coefficient of variation was relatively small in AVI. • In some lobes, AVI associated with the COPD severity despite respiratory level. - Abstract: Purpose: To determine the usefulness of newly-proposed index (attenuation–volume index, AVI: increase in mean value of lung attenuation (MVLA) divided by volume decrease ratio (VDR)) for quantitative assessment of lobar air trapping (LAT) using expiratory/inspiratory (E/I) computed tomography (CT) by minimizing influence of respiratory level. Materials and methods: Institutional review board approved study protocol. Twenty-one moderate or severe COPD (group A), 16 mild COPD (group B) and 26 normal volunteers (group C) underwent both E/I scans via 320-row CT and pulmonary functional test (PFT). Volume image data were automatically segmented into six lung lobes with minimal manual intervention. AVI, pixel index (PI), air trapping ratio (ATR) and relative volume change (RVC{sub 860–950}) were calculated in total lung (TL) and each lobe. Four indices in TL were correlated with both PFT result and VDR and those in TL and each lobe were compared between three groups. Results: Similar to ATR, AVI correlated with both FEV{sub 1}/FVC (r = 0.772, p < 0.01) and RV/TLC (r = −0.726, p < 0.01) and demonstrated a significant difference between three groups in both TL (group A: 1.69 ± 0.45, group B: 2.21 ± 0.45 and group C: 2.80 ± 0.44) and five lobes except for left lingular segment. In a lobe-based analysis regarding relationship with VDR, AVI was much less dependent than ATR, although regression lines of groups A and C were separated for AVI as well as ATR. Coefficient of variation of either PI or RVC{sub 860–950} was significantly

Nuclear ventilation installations. Method of control of the scrubbing coefficient of iodine trap

International Nuclear Information System (INIS)

1982-12-01

The present standard aims at defining a method to control the scrubbing coefficient of radioactive iodine trapping systems, used in nuclear ventilation installations. It applies to the installations where the trapping, efficiency of radioactive iodine has to be known, tested and compared to a reference value generally included in the safety reports. It applies to the installations where the absolute pressure of the air in the ventilation systems is above 1,4. 10 5 Pa (1,4 Bar) [fr

Magnetic Field-Vector Measurements in Quiescent Prominences via the Hanle Effect: Analysis of Prominences Observed at Pic-Du-Midi and at Sacramento Peak

Science.gov (United States)

Bommier, V.; Leroy, J. L.; Sahal-Brechot, S.

1985-01-01

The Hanle effect method for magnetic field vector diagnostics has now provided results on the magnetic field strength and direction in quiescent prominences, from linear polarization measurements in the He I E sub 3 line, performed at the Pic-du-Midi and at Sacramento Peak. However, there is an inescapable ambiguity in the field vector determination: each polarization measurement provides two field vector solutions symmetrical with respect to the line-of-sight. A statistical analysis capable of solving this ambiguity was applied to the large sample of prominences observed at the Pic-du-Midi (Leroy, et al., 1984); the same method of analysis applied to the prominences observed at Sacramento Peak (Athay, et al., 1983) provides results in agreement on the most probable magnetic structure of prominences; these results are detailed. The statistical results were confirmed on favorable individual cases: for 15 prominences observed at Pic-du-Midi, the two-field vectors are pointing on the same side of the prominence, and the alpha angles are large enough with respect to the measurements and interpretation inaccuracies, so that the field polarity is derived without any ambiguity.

Shrew trap efficiency

DEFF Research Database (Denmark)

Gambalemoke, Mbalitini; Mukinzi, Itoka; Amundala, Drazo

2008-01-01

We investigated the efficiency of four trap types (pitfall, Sherman LFA, Victor snap and Museum Special snap traps) to capture shrews. This experiment was conducted in five inter-riverine forest blocks in the region of Kisangani. The total trapping effort was 6,300, 9,240, 5,280 and 5,460 trap......, our results indicate that pitfall traps are the most efficient for capturing shrews: not only do they have a higher efficiency (yield), but the taxonomic diversity of shrews is also higher when pitfall traps are used....

Ultrasonic trap for light scattering measurement

Science.gov (United States)

Barton, Petr; Pavlu, Jiri

2017-04-01

Light scattering is complex phenomenon occurring widely in space environments, including the dense dusty clouds, nebulas or even the upper atmosphere of the Earth. However, when the size of the dust (or of other scattering center) is close to the incident light wavelength, theoretical determination is difficult. In such case, Mie theory is to be used but there is a lack of the material constants for most space-related materials. For experimental measurement of light scattering, we designed unique apparatus, based on ultrasonic trap. Using acoustic levitation we are able to capture the dust grain in midair, irradiate it with laser, and observe scattering directly with goniometer-mounted photodiode. Advantage of this approach is ability to measure directly in the air (thus, no need for the carrier medium) and possibility to study non-spherical particles. Since the trap development is nearly finished and initial experiments are carried out, the paper presents first tests on water droplets.

PROMINENCE ACTIVATION BY CORONAL FAST MODE SHOCK

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Takuya [Department of Astronomy, Kyoto University, Sakyo, Kyoto, 606-8502 (Japan); Asai, Ayumi [Unit of Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Shibata, Kazunari, E-mail: takahashi@kwasan.kyoto-u.ac.jp [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan)

2015-03-01

An X5.4 class flare occurred in active region NOAA11429 on 2012 March 7. The flare was associated with a very fast coronal mass ejection (CME) with a velocity of over 2500 km s{sup −1}. In the images taken with the Solar Terrestrial Relations Observatory-B/COR1, a dome-like disturbance was seen to detach from an expanding CME bubble and propagated further. A Type-II radio burst was also observed at the same time. On the other hand, in extreme ultraviolet images obtained by the Solar Dynamic Observatory/Atmospheric Imaging Assembly (AIA), the expanding dome-like structure and its footprint propagating to the north were observed. The footprint propagated with an average speed of about 670 km s{sup −1} and hit a prominence located at the north pole and activated it. During the activation, the prominence was strongly brightened. On the basis of some observational evidence, we concluded that the footprint in AIA images and the ones in COR1 images are the same, that is, the MHD fast mode shock front. With the help of a linear theory, the fast mode Mach number of the coronal shock is estimated to be between 1.11 and 1.29 using the initial velocity of the activated prominence. Also, the plasma compression ratio of the shock is enhanced to be between 1.18 and 2.11 in the prominence material, which we consider to be the reason for the strong brightening of the activated prominence. The applicability of linear theory to the shock problem is tested with a nonlinear MHD simulation.

Magnetohydrodynamic interpretation of the motion of prominences

International Nuclear Information System (INIS)

Sakurai, Takashi

1976-01-01

We study three types of prominence eruptions, which we will call the arch type, the loop type, and the gigantic arch type, respectively, from their shapes. If we regard the prominence as a magnetic flux tube, the onset of its ascending motion can be interpreted as the motion due to the screw-mode instability, which is the most unstable mode of instabilities of a magnetofluid column (pinch). The growth rate of this mode is evaluated and is shown to be consistent with the time scale of the initial stage of the eruption. In order to study the nonlinear stage of the instability, we propose a method of numerical calculation based on a variational technique known as Ritz's method. The result shows that the characteristic motion of the arch-, loop-, and gigantic arch-type eruptions may be reproduced by perturbing a model sequence with decreasing pitch angles of the unperturbed helical magnetic field lines. This conclusion seems to be supported by the pitch angles of observed threads in each type of prominence and also by the fact that the observed time profiles of the rising velocity of the prominences of each type agree well with those predicted from model calculations. (auth.)

Magnetic traps with a sperical separatrix: Tornado traps

International Nuclear Information System (INIS)

Peregood, B.P.; Lehnert, B.

1979-11-01

A review is given on the features of magnetic traps with a spherical separatrix, with special emphesis on Tornado spiral coil configurations. The confinement and heating of static plasmas in Tornado traps is treated, including the topology of the magnetic field structure, the magneto-mechanical properties of the magnetic coil system, as well as the particle orbits and plasma behaviour in these traps. In additio, the mode of rotating plasma operation by crossed electric and magnetic fields is being described. The results of experiments on static and rotating plasmas are summarized, and conclusions are drawn about future possibilities of Tornado traps for the creation and containment of hot plasmas. (author)

Magnetic traps with a spherical separatrix: Tornado traps

International Nuclear Information System (INIS)

Peregood, B.P.; Lehnert, B.

1981-01-01

A review is given on the features of magnetic traps with a spherical separatrix, with special emphasis on Tornado spiral coil configurations. The confinement and heating of static plasms in Tornado traps is treated, including the topology of the magnetic field structure, the magneto-mechanical properties of the magnetic coil system, as well as the particle orbits and plasma behaviour in these traps. In addition, the mode of rotating plasma operation by crossed electric and magnetic fields is described. The results of experiments on static and rotating plasmas are summarized, and conclusions are drawn about future possibilities of Tornado traps in the creation and containment of hot plasmas. (orig.)

50 CFR 697.19 - Trap limits and trap tag requirements for vessels fishing with lobster traps.

Science.gov (United States)

2010-10-01

... vessels fishing with lobster traps. 697.19 Section 697.19 Wildlife and Fisheries FISHERY CONSERVATION AND... requirements for vessels fishing with lobster traps. (a) Trap limits for vessels fishing or authorized to fish... management area designation certificate or valid limited access American lobster permit specifying one or...

Solar Magnetized Tornadoes: Rotational Motion in a Tornado-like Prominence

Science.gov (United States)

Su, Yang; Gömöry, Peter; Veronig, Astrid; Temmer, Manuela; Wang, Tongjiang; Vanninathan, Kamalam; Gan, Weiqun; Li, YouPing

2014-04-01

Su et al. proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the prominence leg, supporting the so-called prominence-corona transition region. The opposite velocities at the two sides of the prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of ~5 km s-1.

Morphology and Dynamics of Solar Prominences from 3D MHD Simulations

Science.gov (United States)

Terradas, J.; Soler, R.; Luna, M.; Oliver, R.; Ballester, J. L.

2015-01-01

In this paper we present a numerical study of the time evolution of solar prominences embedded in sheared magnetic arcades. The prominence is represented by a density enhancement in a background-stratified atmosphere and is connected to the photosphere through the magnetic field. By solving the ideal magnetohydrodynamic equations in three dimensions, we study the dynamics for a range of parameters representative of real prominences. Depending on the parameters considered, we find prominences that are suspended above the photosphere, i.e., detached prominences, but also configurations resembling curtain or hedgerow prominences whose material continuously connects to the photosphere. The plasma-β is an important parameter that determines the shape of the structure. In many cases magnetic Rayleigh-Taylor instabilities and oscillatory phenomena develop. Fingers and plumes are generated, affecting the whole prominence body and producing vertical structures in an essentially horizontal magnetic field. However, magnetic shear is able to reduce or even to suppress this instability.

MORPHOLOGY AND DYNAMICS OF SOLAR PROMINENCES FROM 3D MHD SIMULATIONS

Energy Technology Data Exchange (ETDEWEB)

Terradas, J.; Soler, R.; Oliver, R.; Ballester, J. L. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Luna, M., E-mail: jaume.terradas@uib.es [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain)

2015-01-20

In this paper we present a numerical study of the time evolution of solar prominences embedded in sheared magnetic arcades. The prominence is represented by a density enhancement in a background-stratified atmosphere and is connected to the photosphere through the magnetic field. By solving the ideal magnetohydrodynamic equations in three dimensions, we study the dynamics for a range of parameters representative of real prominences. Depending on the parameters considered, we find prominences that are suspended above the photosphere, i.e., detached prominences, but also configurations resembling curtain or hedgerow prominences whose material continuously connects to the photosphere. The plasma-β is an important parameter that determines the shape of the structure. In many cases magnetic Rayleigh-Taylor instabilities and oscillatory phenomena develop. Fingers and plumes are generated, affecting the whole prominence body and producing vertical structures in an essentially horizontal magnetic field. However, magnetic shear is able to reduce or even to suppress this instability.

Molecular adsorption steers bacterial swimming at the air/water interface.

Science.gov (United States)

Morse, Michael; Huang, Athena; Li, Guanglai; Maxey, Martin R; Tang, Jay X

2013-07-02

Microbes inhabiting Earth have adapted to diverse environments of water, air, soil, and often at the interfaces of multiple media. In this study, we focus on the behavior of Caulobacter crescentus, a singly flagellated bacterium, at the air/water interface. Forward swimming C. crescentus swarmer cells tend to get physically trapped at the surface when swimming in nutrient-rich growth medium but not in minimal salt motility medium. Trapped cells move in tight, clockwise circles when viewed from the air with slightly reduced speed. Trace amounts of Triton X100, a nonionic surfactant, release the trapped cells from these circular trajectories. We show, by tracing the motion of positively charged colloidal beads near the interface that organic molecules in the growth medium adsorb at the interface, creating a high viscosity film. Consequently, the air/water interface no longer acts as a free surface and forward swimming cells become hydrodynamically trapped. Added surfactants efficiently partition to the surface, replacing the viscous layer of molecules and reestablishing free surface behavior. These findings help explain recent similar studies on Escherichia coli, showing trajectories of variable handedness depending on media chemistry. The consistent behavior of these two distinct microbial species provides insights on how microbes have evolved to cope with challenging interfacial environments. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Cryogenic surface ion traps

International Nuclear Information System (INIS)

Niedermayr, M.

2015-01-01

Microfabricated surface traps are a promising architecture to realize a scalable quantum computer based on trapped ions. In principle, hundreds or thousands of surface traps can be located on a single substrate in order to provide large arrays of interacting ions. To this end, trap designs and fabrication methods are required that provide scalable, stable and reproducible ion traps. This work presents a novel surface-trap design developed for cryogenic applications. Intrinsic silicon is used as the substrate material of the traps. The well-developed microfabrication and structuring methods of silicon are utilized to create simple and reproducible traps. The traps were tested and characterized in a cryogenic setup. Ions could be trapped and their life time and motional heating were investigated. Long ion lifetimes of several hours were observed and the measured heating rates were reproducibly low at around 1 phonon per second at a trap frequency of 1 MHz. (author) [de

Artificial covering on trap nests improves the colonization of trap-nesting wasps

OpenAIRE

Taki, Hisatomo; Kevan, Peter G.; Viana, Blandina Felipe; Silva, Fabiana O.; Buck, Matthias

2008-01-01

Acesso restrito: Texto completo. p. 225-229 To evaluate the role that a trap-nest cover might have on sampling methodologies, the abundance of each species of trap-nesting Hymenoptera and the parasitism rate in a Canadian forest were compared between artificially covered and uncovered traps. Of trap tubes exposed at eight forest sites in six trap-nest boxes, 531 trap tubes were occupied and 1216 individuals of 12 wasp species of four predatory families, Vespidae (Eumeninae), Crabronidae...

Reconnection–Condensation Model for Solar Prominence Formation

Energy Technology Data Exchange (ETDEWEB)

Kaneko, Takafumi [Institute for Space-Earth Environmental Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan); Yokoyama, Takaaki, E-mail: kaneko@isee.nagoya-u.ac.jp [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2017-08-10

We propose a reconnection–condensation model in which topological change in a coronal magnetic field via reconnection triggers radiative condensation, thereby resulting in prominence formation. Previous observational studies have suggested that reconnection at a polarity inversion line of a coronal arcade field creates a flux rope that can sustain a prominence; however, they did not explain the origin of cool dense plasmas of prominences. Using three-dimensional magnetohydrodynamic simulations, including anisotropic nonlinear thermal conduction and optically thin radiative cooling, we demonstrate that reconnection can lead not only to flux rope formation but also to radiative condensation under a certain condition. In our model, this condition is described by the Field length, which is defined as the scale length for thermal balance between radiative cooling and thermal conduction. This critical condition depends weakly on the artificial background heating. The extreme ultraviolet emissions synthesized with our simulation results have good agreement with observational signatures reported in previous studies.

Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap

CERN Document Server

Amole, C; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Hydomako, R; Kurchaninov, L; Jonsell, S; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S

2012-01-01

Recently, antihydrogen atoms were trapped at CERN in a magnetic minimum (minimum-B) trap formed by superconducting octupole and mirror magnet coils. The trapped antiatoms were detected by rapidly turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. Once released, these antiatoms quickly hit the trap wall, whereupon the positrons and antiprotons in the antiatoms annihilated. The antiproton annihilations produce easily detected signals; we used these signals to prove that we trapped antihydrogen. However, our technique could be confounded by mirror-trapped antiprotons, which would produce seemingly-identical annihilation signals upon hitting the trap wall. In this paper, we discuss possible sources of mirror-trapped antiprotons and show that antihydrogen and antiprotons can be readily distinguished, often with the aid of applied electric fields, by analyzing the annihilation locations and times. We further discuss the general properties of antipr...

Stable Trapping of Multielectron Helium Bubbles in a Paul Trap

Science.gov (United States)

Joseph, E. M.; Vadakkumbatt, V.; Pal, A.; Ghosh, A.

2017-06-01

In a recent experiment, we have used a linear Paul trap to store and study multielectron bubbles (MEBs) in liquid helium. MEBs have a charge-to-mass ratio (between 10^{-4} and 10^{-2} C/kg) which is several orders of magnitude smaller than ions (between 10^6 and 10^8 C/kg) studied in traditional ion traps. In addition, MEBs experience significant drag force while moving through the liquid. As a result, the experimental parameters for stable trapping of MEBs, such as magnitude and frequency of the applied electric fields, are very different from those used in typical ion trap experiments. The purpose of this paper is to model the motion of MEBs inside a linear Paul trap in liquid helium, determine the range of working parameters of the trap, and compare the results with experiments.

Physics of solar prominences. Proceedings of the Colloquium, Oslo, Norway, August 14-18, 1978

Energy Technology Data Exchange (ETDEWEB)

Jensen, E; Maltby, P

1979-01-01

These papers deal with recent theoretical and observational studies of the physics of solar prominences. Specific topics include reviews of prominence spectra and their interpretation, polarimetric observations and magnetic-field determination in prominences, observations of the prominence-corona interface, theories on the formation and stability of quiescent prominences, prominence classifications, observations of active prominences, observations and interpretations of coronal manifestations of eruptive prominences, and models of prominence structure and dynamics. Other contributions discuss simultaneous observations of Ca II and hydrogen Balmer lines in quiescent prominences, recent results in quiescent-prominence spectroscopy, the solar helium abundance obtained from optical spectra of quiescent prominences, and Stokes polarimetry of quiescent prominences in the He I D3 line. Magnetic-field determination based on the Hanle effect is also examined, along with the orientation of prominence microstructure relative to magnetic-field direction, radio observations of quiescent-prominence filaments at centimeter and millimeter wavelengths, EUV observations of filaments, and a magnetic-field reconnection model of quiescent prominences.

Evaluation of trapping parameters of thermally stimulated luminescence glow curves in Cu-doped Li2B4O7 phosphor

International Nuclear Information System (INIS)

Manam, J.; Sharma, S.K.

2005-01-01

Evaluation of trapping parameters, including order of kinetics, activation energy and frequency factor, is one of the most important aspect of studies in the field of thermally stimulated luminescence (TSL). A polycrystalline sample of Cu-doped Li 2 B 4 O 7 was prepared by the melting method. Formation of the doped compound was checked by use of Fourier-transform infrared (FTIR) spectroscopy. TSL studies of the Cu-doped lithium tetraborate sample shows three glow peaks, the maximum emission occurring, respectively, at a temperature of 175 deg. C, 290 deg. C and 350 deg. C, the intensity of the 175 deg. C-glow peak being the maximum. The trapping parameters associated with this prominent glow peak of Cu-doped lithium tetraborate are reported herein, using the isothermal luminescence decay and glow curve shape (Chen's) methods. Our results show very good agreement between the trapping parameters calculated by the two methods

Experimental and Numerical Investigation of Effect of Air Stability on Exhaled Air Dispersion

DEFF Research Database (Denmark)

Xu, Chunwen; Gong, Guangcai; Nielsen, Peter Vilhelm

2014-01-01

studies. As the thermal stratification under displacement ventilation blocks the vertical movement of exhaled air, the exhaled contaminant may be trapped between temperature stratifications. As the dispersion of contaminant is closely related to the health of human indoors, the temperature structure...... was used for experimental study, and a numerical person was built to simulate the manikin. The velocity, temperature and concentration of tracer gas in exhaled air are affected by air stability to different degrees. The similarity of this effect among these parameters can also be observed through numerical...

Study of a Large Helical Eruptive Prominence Associated with ...

Indian Academy of Sciences (India)

2001-04-21

Apr 21, 2001 ... morphology of the event, energy budget of the prominence and associated. CMEs. ... magnetically driven and internally powered. Key words. ... Solar prominences are ribbons of cool (∼8000 K) dense gas (∼10. −11 gcm. −3. ) ...

SOLAR MAGNETIZED TORNADOES: ROTATIONAL MOTION IN A TORNADO-LIKE PROMINENCE

Energy Technology Data Exchange (ETDEWEB)

Su, Yang; Veronig, Astrid; Temmer, Manuela; Vanninathan, Kamalam [IGAM-Kanzelhöhe Observatory, Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria); Gömöry, Peter [Astronomical Institute of the Slovak Academy of Sciences, SK-05960 Tatranská Lomnica (Slovakia); Wang, Tongjiang [Department of Physics, the Catholic University of America, Washington, DC 20064 (United States); Gan, Weiqun; Li, YouPing, E-mail: yang.su@uni-graz.at [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

2014-04-10

Su et al. proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the prominence leg, supporting the so-called prominence-corona transition region. The opposite velocities at the two sides of the prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of ∼5 km s{sup –1}.

SOLAR MAGNETIZED TORNADOES: ROTATIONAL MOTION IN A TORNADO-LIKE PROMINENCE

International Nuclear Information System (INIS)

Su, Yang; Veronig, Astrid; Temmer, Manuela; Vanninathan, Kamalam; Gömöry, Peter; Wang, Tongjiang; Gan, Weiqun; Li, YouPing

2014-01-01

Su et al. proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the prominence leg, supporting the so-called prominence-corona transition region. The opposite velocities at the two sides of the prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of ∼5 km s –1

Gas-partitioning tracer test to qualify trapped gas during recharge

Science.gov (United States)

Heilweil, Victor M.; Kip, Solomon D.; Perkins, Kim S.; Ellett, Kevin M.

2004-01-01

Dissolved helium and bromide tracers were used to evaluate trapped gas during an infiltration pond experiment. Dissolved helium preferentially partitioned into trapped gas bubbles, or other pore air, because of its low solubility in water. This produced observed helium retardation factors of as much as 12 relative to bromide. Numerical simulations of helium breakthrough with both equilibrium and kinetically limited advection/dispersion/retardation did not match observed helium concentrations. However, better fits were obtained by including a decay term representing the diffusive loss of helium through interconnected, gas-filled pores. Calculations indicate that 7% to more than 26% of the porosity beneath the pond was filled with gas. Measurements of laboratory hydraulic properties indicate that a 10% decrease in saturation would reduce the hydraulic conductivity by at least one order of magnitude in the well-sorted sandstone, but less in the overlying soils. This is consistent with in situ measurements during the experiment, which show steeper hydraulic gradients in sandstone than in soil. Intrinsic permeability of the soil doubled during the first six months of the experiment, likely caused by a combination of dissolution and thermal contraction of trapped gas. Managers of artificial recharge basins may consider minimizing the amount of trapped gas by using wet, rather than dry, tilling to optimize infiltration rates, particularly in well-sorted porous media in which reintroduced trapped gas may cause substantial reductions in permeability. Trapped gas may also inhibit the amount of focused infiltration that occurs naturally during ephemeral flood events along washes and playas.

Gas-partitioning tracer test to quantify trapped gas during recharge

Science.gov (United States)

Heilweil, V.M.; Solomon, D.K.; Perkins, K.S.; Ellett, K.M.

2004-01-01

Dissolved helium and bromide tracers were used to evaluate trapped gas during an infiltration pond experiment. Dissolved helium preferentially partitioned into trapped gas bubbles, or other pore air, because of its low solubility in water. This produced observed helium retardation factors of as much as 12 relative to bromide. Numerical simulations of helium breakthrough with both equilibrium and kinetically limited advection/dispersion/retardation did not match observed helium concentrations. However, better fits were obtained by including a decay term representing the diffusive loss of helium through interconnected, gas-filled pores. Calculations indicate that 7% to more than 26% of the porosity beneath the pond was filled with gas. Measurements of laboratory hydraulic properties indicate that a 10% decrease in saturation would reduce the hydraulic conductivity by at least one order of magnitude in the well-sorted sandstone, but less in the overlying soils. This is consistent with in situ measurements during the experiment, which show steeper hydraulic gradients in sandstone than in soil. Intrinsic permeability of the soil doubled during the first six months of the experiment, likely caused by a combination of dissolution and thermal contraction of trapped gas. Managers of artificial recharge basins may consider minimizing the amount of trapped gas by using wet, rather than dry, tilling to optimize infiltration rates, particularly in well-sorted porous media in which reintroduced trapped gas may cause substantial reductions in permeability. Trapped gas may also inhibit the amount of focused infiltration that occurs naturally during ephemeral flood events along washes and playas.

Prominence-corona interface compared with the chromosphere-corona transition region

Energy Technology Data Exchange (ETDEWEB)

Orrall, F Q; Schmahl, E J [Harvard Coll. Observatory, Cambridge, Mass. (USA)

1976-11-01

The intensities of 52 EUV emission lines from each of 9 hedgerow prominences observed at the limb with the Harvard experiment on ATM-Skylab have been compared with intensities from the interior of network cells at the center of the disk, in order to compare the prominence-corona (P-C) interface with the chromosphere-corona (C-C) transition region. The intensity ratio Isub(cell)/Isub(prominence) for each line varies systematically (in all of the prominences observed), with the temperature of formation of the line as approximately Tsup(-0.6). The density sensitive C III (formed at T approximately 9x10/sup 4/ K) line ratio Isub(lambda1175)/Isub(lambda977) implies an average density 1.3x10/sup 9/ electrons cm/sup -3/ in the P-C interface and approximately 4 times this value in the C-C transition of the cells. The total optical thickness at the head of the Lyman continuum is < approximately 10 in most of the prominences studied; in two of the prominences, however, the possibility that tau/sub 0/ is large cannot be rejected. Methods of analysis of these EUV data are developed assuming both a resolved and an unresolved internal prominence structure. Although the systematic differences between the P-C interface and the C-C transition are stressed, the similarities are probably more remarkable and may be a result of fine structure in the C-C transition.

Improved air trapping evaluation in chest computed tomography in children with cystic fibrosis using real-time spirometric monitoring and biofeedback

DEFF Research Database (Denmark)

Kongstad, Thomas; Buchvald, Frederik F; Green, Kent

2013-01-01

CTs were evaluated. Mean (95%CI) change in inspiratory-expiratory lung density differences was 436 Hounsfield Units (HU) (408 to 464) in the COP cohort with spirometric breath hold monitoring versus 229 HU (188 to 269) in the GOT cohort with unmonitored breath hold manoeuvres (p...BACKGROUND: The quality of chest Computed Tomography (CT) images in children is dependent upon a sufficient breath hold during CT scanning. This study evaluates the influence of spirometric breath hold monitoring with biofeedback software on inspiratory and expiratory chest CT lung density measures......, and on trapped air (TA) scoring in children with cystic fibrosis (CF). This is important because TA is an important component of early and progressive CF lung disease. METHODS: A cross sectional comparison study was completed for chest CT imaging in two cohorts of CF children with comparable disease severity...

Air loads on solar panels during launch

NARCIS (Netherlands)

Beltman, W.M.; van der Hoogt, Peter; Spiering, R.M.E.J.; Tijdeman, H.

1996-01-01

The dynamical behaviour of solar panels during launch is significantly affected by the thin layers of air trapped between the panels. For narrow gaps the air manifests itself not only as a considerable added mass, but its viscosity can result in a substantial amount of damping. A model has been

Application of Needle Trap Device Packed with Polydimethylsiloxane for Determination of Carbon Tetrachloride and Trichloroethylene in Air

Directory of Open Access Journals (Sweden)

M. Heidari

2014-04-01

Full Text Available Introduction & Objective: The use of modern microextraction techniques for determination and evaluation of pollutants is progressively increasing nowadays. Needle trap microextraction (NTME technique has privileges compared to the other techniques for sampling occupa-tional and environmental pollutants from air. In this study the application of NTD technique packed with polydimethylsiloxane as sorbent for determination of two organohalogen com-pounds (carbon tetrachloride and trichloroethylene was investigated. Material & Methods: In this experimental study NTDs were prepared with the same length of proposed sorbent and used after calibration of sampling pump. The parameters related to per-formance of NTD and proposed sorbent including temperature and relative humidity, sam-pling storage time and breakthrough volume were investigated. In analytical performances, the capability of NTD on time and temperature of desorption also carryover of analytes were assessed. Finally, the results for NTD microextraction e were compared to the NIOSH 1003 method. Results: Results have shown that, temperature and relative humidity had effects on the per-formance of NTD and it's sorbent, and NTD contained PDMS showed better performance in the lower temperature and relative humidity at the range of assessment. The performance of NTD and it's sorbent for storage of sampled analytes was more than 95% of analytes mass after 4 days of sampling. The proposed technique also showed a good performance for de-sorption parameters and desorption temperature and time was 290?C and 4 minutes, respec-tively. After desorption, the carryover was also investigated and measured as 4 min. Relative standard division (RSD for repeatability of method for NTD from different concentration levels of 1-250 µgL-1were 4.1-7.5%. Conclusions: The NTD technique as an active sampling method with high enrichment factor showed a good performance for sampling and analysis of volatile organohalogen

Nematode-Trapping Fungi.

Science.gov (United States)

Jiang, Xiangzhi; Xiang, Meichun; Liu, Xingzhong

2017-01-01

Nematode-trapping fungi are a unique and intriguing group of carnivorous microorganisms that can trap and digest nematodes by means of specialized trapping structures. They can develop diverse trapping devices, such as adhesive hyphae, adhesive knobs, adhesive networks, constricting rings, and nonconstricting rings. Nematode-trapping fungi have been found in all regions of the world, from the tropics to Antarctica, from terrestrial to aquatic ecosystems. They play an important ecological role in regulating nematode dynamics in soil. Molecular phylogenetic studies have shown that the majority of nematode-trapping fungi belong to a monophyletic group in the order Orbiliales (Ascomycota). Nematode-trapping fungi serve as an excellent model system for understanding fungal evolution and interaction between fungi and nematodes. With the development of molecular techniques and genome sequencing, their evolutionary origins and divergence, and the mechanisms underlying fungus-nematode interactions have been well studied. In recent decades, an increasing concern about the environmental hazards of using chemical nematicides has led to the application of these biological control agents as a rapidly developing component of crop protection.

Developing a passive trap for diffusive atmospheric {sup 14}CO{sub 2} sampling

Energy Technology Data Exchange (ETDEWEB)

Walker, Jennifer C.; Xu, Xiaomei [Department of Earth System Science, University of California, Irvine, Irvine, CA (United States); Fahrni, Simon M. [Department of Earth System Science, University of California, Irvine, Irvine, CA (United States); Institute of Particle Physics, ETH, Zurich (Switzerland); Lupascu, Massimo [Department of Earth System Science, University of California, Irvine, Irvine, CA (United States); Department of Geography, National University of Singapore (Singapore); Czimczik, Claudia I. [Department of Earth System Science, University of California, Irvine, Irvine, CA (United States)

2015-10-15

{sup 14}C-CO{sub 2} measurement is an unique tool to quantify source-based emissions of CO{sub 2} for both the urban and natural environments. Acquiring a sample that temporally integrates the atmospheric {sup 14}C-CO{sub 2} signature that allows for precise {sup 14}C analysis is often necessary, but can require complex sampling devices, which can be difficult to deploy and maintain, especially for multiple locations. Here we describe our progress in developing a diffusive atmospheric CO{sub 2} molecular sieve trap, which requires no power to operate. We present results from various cleaning procedures, and rigorously tested for blank and memory effects. Traps were tested in the environment along-side conventional sampling flasks for accuracy. Results show that blank and memory effects can be minimized with thorough cleaning and by avoiding overheating, and that diffusively collected air samples agree well with traditionally canister-sampled air.

Radiation induced traps of zinc phosphate and phosphide

International Nuclear Information System (INIS)

Murali, K.R.; Rao, D.R.

1980-01-01

Thermoluminescence (TL) glow curve (TGC) method has been used to study the traps produced by X-irradiation in Zn 3 (PO 4 ) 2 and Zn 3 P 2 . Prominent TL glow peaks were observed at 100 0 and 360 0 C for zinc phosphate while for zinc phosphide only one glow peak at 245 0 C was observed, and in the latter case the TL output was in general quite low compared to zinc phosphate. The TL spectra for both the glow peaks of zinc phosphate indicated emission band in the region around 560 nm, while for zinc phosphide the emission occurred at 575 nm (in the temperature region 200-270 0 C). The low temperature glow peaks below 270 0 C were less stable compared to those above 300 0 C and were completely destroyed when the irradiated samples were stored in darkness for 24 hr at room temperature. Shining by 470 nm light however produced preferential bleaching of the two TL peaks at 100 and 360 0 C with no effect on the 245 0 C glow peak of zinc phosphide. It is concluded that during heat treatment large numbers of Zn-vacancies are formed due to which complexes like Zn-P are produced by irradiation and the TL traps destroyed in a radiative recombination process are related with these complexes. (author)

MULTI-LINE STOKES INVERSION FOR PROMINENCE MAGNETIC-FIELD DIAGNOSTICS

International Nuclear Information System (INIS)

Casini, R.; Lopez Ariste, A.; Paletou, F.; Leger, L.

2009-01-01

We present test results on the simultaneous inversion of the Stokes profiles of the He I lines at 587.6 nm (D 3 ) and 1083.0 nm in prominences (90 deg. scattering). We created data sets of synthetic Stokes profiles for the case of quiescent prominences (B -3 of the peak intensity for the polarimetric sensitivity of the simulated observations. In this work, we focus on the error analysis for the inference of the magnetic field vector, under the usual assumption that the prominence can be assimilated to a slab of finite optical thickness with uniform magnetic and thermodynamic properties. We find that the simultaneous inversion of the two lines significantly reduces the errors on the inference of the magnetic field vector, with respect to the case of single-line inversion. These results provide a solid justification for current and future instrumental efforts with multi-line capabilities for the observations of solar prominences and filaments.

Characteristics of trapped electrons and electron traps in single crystals

International Nuclear Information System (INIS)

Budzinski, E.E.; Potter, W.R.; Potienko, G.; Box, H.C.

1979-01-01

Two additional carbohydrates are reported whose crystal structures trap electrons intermolecularly in single crystals x irradiated at low temperature, namely sucrose and rhamnose. Five carbohydrate and polyhydroxy compounds are now known which exhibit this phenomenon. The following characteristics of the phenomenon were investigated: (1) the hyperfine couplings of the electron with protons of the polarized hydroxy groups forming the trap; (2) the distances between these protons and the trapped electron; (3) the spin density of the electron at the protons and (4) the relative stabilities of the electron trapped in various crystal structures

Physics of Solar Prominences: I-Spectral Diagnostics and Non-LTE Modelling

Science.gov (United States)

Labrosse, N.; Heinzel, P.; Vial, J.-C,; Kucera, T.; Parenti, S.; Gunar, S.; Schmieder, B.; Kilper, G.

2010-01-01

This review paper outlines background information and covers recent advances made via the analysis of spectra and images of prominence plasma and the increased sophistication of non-LTE (i.e. when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have been used to infer the plasma parameters important for the general properties of the prominence plasma in both its cool core and the hotter prominence-corona transition region. We also review studies devoted to the observation of bulk motions of the prominence plasma and to the determination of prominence mass. However, a simple inversion of spectroscopic data usually fails when the lines become optically thick at certain wavelengths. Therefore, complex

Solar Prominence Modelling and Plasma Diagnostics at ALMA Wavelengths

Science.gov (United States)

Rodger, Andrew; Labrosse, Nicolas

2017-09-01

Our aim is to test potential solar prominence plasma diagnostics as obtained with the new solar capability of the Atacama Large Millimeter/submillimeter Array (ALMA). We investigate the thermal and plasma diagnostic potential of ALMA for solar prominences through the computation of brightness temperatures at ALMA wavelengths. The brightness temperature, for a chosen line of sight, is calculated using the densities of electrons, hydrogen, and helium obtained from a radiative transfer code under non-local thermodynamic equilibrium (non-LTE) conditions, as well as the input internal parameters of the prominence model in consideration. Two distinct sets of prominence models were used: isothermal-isobaric fine-structure threads, and large-scale structures with radially increasing temperature distributions representing the prominence-to-corona transition region. We compute brightness temperatures over the range of wavelengths in which ALMA is capable of observing (0.32 - 9.6 mm), however, we particularly focus on the bands available to solar observers in ALMA cycles 4 and 5, namely 2.6 - 3.6 mm (Band 3) and 1.1 - 1.4 mm (Band 6). We show how the computed brightness temperatures and optical thicknesses in our models vary with the plasma parameters (temperature and pressure) and the wavelength of observation. We then study how ALMA observables such as the ratio of brightness temperatures at two frequencies can be used to estimate the optical thickness and the emission measure for isothermal and non-isothermal prominences. From this study we conclude that for both sets of models, ALMA presents a strong thermal diagnostic capability, provided that the interpretation of observations is supported by the use of non-LTE simulation results.

Improving accuracy and precision of ice core δD(CH4 analyses using methane pre-pyrolysis and hydrogen post-pyrolysis trapping and subsequent chromatographic separation

Directory of Open Access Journals (Sweden)

M. Bock

2014-07-01

Full Text Available Firn and polar ice cores offer the only direct palaeoatmospheric archive. Analyses of past greenhouse gas concentrations and their isotopic compositions in air bubbles in the ice can help to constrain changes in global biogeochemical cycles in the past. For the analysis of the hydrogen isotopic composition of methane (δD(CH4 or δ2H(CH4 0.5 to 1.5 kg of ice was hitherto used. Here we present a method to improve precision and reduce the sample amount for δD(CH4 measurements in (ice core air. Pre-concentrated methane is focused in front of a high temperature oven (pre-pyrolysis trapping, and molecular hydrogen formed by pyrolysis is trapped afterwards (post-pyrolysis trapping, both on a carbon-PLOT capillary at −196 °C. Argon, oxygen, nitrogen, carbon monoxide, unpyrolysed methane and krypton are trapped together with H2 and must be separated using a second short, cooled chromatographic column to ensure accurate results. Pre- and post-pyrolysis trapping largely removes the isotopic fractionation induced during chromatographic separation and results in a narrow peak in the mass spectrometer. Air standards can be measured with a precision better than 1‰. For polar ice samples from glacial periods, we estimate a precision of 2.3‰ for 350 g of ice (or roughly 30 mL – at standard temperature and pressure (STP – of air with 350 ppb of methane. This corresponds to recent tropospheric air samples (about 1900 ppb CH4 of about 6 mL (STP or about 500 pmol of pure CH4.

ON THE MAGNETISM AND DYNAMICS OF PROMINENCE LEGS HOSTING TORNADOES

International Nuclear Information System (INIS)

Martínez González, M. J.; Ramos, A. Asensio; Arregui, I.; Collados, M.; Beck, C.; Rodríguez, J. de la Cruz

2016-01-01

Solar tornadoes are dark vertical filamentary structures observed in the extreme ultraviolet associated with prominence legs and filament barbs. Their true nature and relationship to prominences requires an understanding of their magnetic structure and dynamic properties. Recently, a controversy has arisen: is the magnetic field organized forming vertical, helical structures or is it dominantly horizontal? And concerning their dynamics, are tornadoes really rotating or is it just a visual illusion? Here we analyze four consecutive spectro-polarimetric scans of a prominence hosting tornadoes on its legs, which helps us shed some light on their magnetic and dynamical properties. We show that the magnetic field is very smooth in all the prominence, which is probably an intrinsic property of the coronal field. The prominence legs have vertical helical fields that show slow temporal variation that is probably related to the motion of the fibrils. Concerning the dynamics, we argue that (1) if rotation exists, it is intermittent, lasting no more than one hour, and (2) the observed velocity pattern is also consistent with an oscillatory velocity pattern (waves).

ON THE MAGNETISM AND DYNAMICS OF PROMINENCE LEGS HOSTING TORNADOES

Energy Technology Data Exchange (ETDEWEB)

Martínez González, M. J.; Ramos, A. Asensio; Arregui, I.; Collados, M. [Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain); Beck, C. [National Solar Observatory, Sacramento Peak P.O. Box 62, Sunspot, NM 88349 (United States); Rodríguez, J. de la Cruz [Institute for Solar Physics, Department of Astronomy, Stockholm University, Albanova University Center, SE-10691 Stockholm (Sweden)

2016-07-10

Solar tornadoes are dark vertical filamentary structures observed in the extreme ultraviolet associated with prominence legs and filament barbs. Their true nature and relationship to prominences requires an understanding of their magnetic structure and dynamic properties. Recently, a controversy has arisen: is the magnetic field organized forming vertical, helical structures or is it dominantly horizontal? And concerning their dynamics, are tornadoes really rotating or is it just a visual illusion? Here we analyze four consecutive spectro-polarimetric scans of a prominence hosting tornadoes on its legs, which helps us shed some light on their magnetic and dynamical properties. We show that the magnetic field is very smooth in all the prominence, which is probably an intrinsic property of the coronal field. The prominence legs have vertical helical fields that show slow temporal variation that is probably related to the motion of the fibrils. Concerning the dynamics, we argue that (1) if rotation exists, it is intermittent, lasting no more than one hour, and (2) the observed velocity pattern is also consistent with an oscillatory velocity pattern (waves).

Resonant nano-antennas for light trapping in plasmonic solar cells

Energy Technology Data Exchange (ETDEWEB)

Mokkapati, S; Beck, F J; Catchpole, K R [Centre for Sustainable Energy Systems, College of Engineering and Computer Science, Australian National University, Canberra, 0200 (Australia); De Waele, R; Polman, A, E-mail: sudha.mokkapati@anu.edu.au [Center for Nanophotonics, FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam (Netherlands)

2011-05-11

We investigate the influence of nanoparticle height on light trapping in thin-film solar cells covered with metal nanoparticles. We show that in taller nanoparticles the scattering cross-section is enhanced by resonant excitation of plasmonic standing waves. Tall nanoparticles have higher coupling efficiency when placed on the illuminated surface of the cell than on the rear of the cell due to their forward scattering nature. One of the major factors affecting the coupling efficiency of these particles is the phase shift of surface plasmon polaritons propagating along the nanoparticle due to reflection from the Ag/Si or Ag/air interface. The high scattering cross-sections of tall nanoparticles on the illuminated surface of the cell could be exploited for efficient light trapping by modifying the coupling efficiency of nanoparticles by engineering this phase shift. We demonstrate that the path length enhancement (with a nanoparticle of height 500 nm) at an incident wavelength of 700 nm can be increased from {approx}6 to {approx}16 by modifying the phase shift at the Ag/air interface by coating the surface of the nanoparticle with a layer of Si.

Trapping, self-trapping and the polaron family

International Nuclear Information System (INIS)

Stoneham, A M; Gavartin, J; Shluger, A L; Kimmel, A V; Ramo, D Munoz; Roennow, H M; Aeppli, G; Renner, C

2007-01-01

The earliest ideas of the polaron recognized that the coupling of an electron to ionic vibrations would affect its apparent mass and could effectively immobilize the carrier (self-trapping). We discuss how these basic ideas have been generalized to recognize new materials and new phenomena. First, there is an interplay between self-trapping and trapping associated with defects or with fluctuations in an amorphous solid. In high dielectric constant oxides, like HfO 2 , this leads to oxygen vacancies having as many as five charge states. In colossal magnetoresistance manganites, this interplay makes possible the scanning tunnelling microscopy (STM) observation of polarons. Second, excitons can self-trap and, by doing so, localize energy in ways that can modify the material properties. Third, new materials introduce new features, with polaron-related ideas emerging for uranium dioxide, gate dielectric oxides, Jahn-Teller systems, semiconducting polymers and biological systems. The phonon modes that initiate self-trapping can be quite different from the longitudinal optic modes usually assumed to dominate. Fourth, there are new phenomena, like possible magnetism in simple oxides, or with the evolution of short-lived polarons, like muons or excitons. The central idea remains that of a particle whose properties are modified by polarizing or deforming its host solid, sometimes profoundly. However, some of the simpler standard assumptions can give a limited, indeed misleading, description of real systems, with qualitative inconsistencies. We discuss representative cases for which theory and experiment can be compared in detail

Iodine Gas Trapping using Granular Porous Bismuth

Energy Technology Data Exchange (ETDEWEB)

Yang, Jae Hwan; Shin, Jin Myeong; Park, Jang Jin; Park, Geun Il [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Yim, Mansung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2014-05-15

{sup 129}I is a radionuclide with a very long half-life of 1.57 Χ 10{sup 7} years and has negative health effects to the human body. Therefore, the emission of {sup 129}I into the air is closely regulated by the Environmental Protection Agency (EPA). Many methods for trapping gaseous {sup 129}I have been developed thus far, including wet scrubbing and adsorption using silver loaded zeolites. Although wet scrubbing can effectively remove iodine, it suffers from corrosion of the vessel due to high concentration of the scrubbing solution. Silver loaded zeolites also show effectiveness in capturing {sup 129}I gas, yet weak thermal stability of physisorbed iodine remains a challenge. We studied a novel and facile method to trap iodine gas using bismuth. Granular bismuth having many pores was synthesized using bismuth nitrate and polyvinyl alcohol as a bismuth precursor and pore forming agent, respectively. Reaction of iodine and our samples resulted in an iodine capturing capacity of more than 2 times that of the commercial grade silver exchanged zeolite (AgX). Granular porous bismuths synthesized using bismuth nitrate and PVA show a promising performance in capturing iodine gas. The use of bismuth in trapping {sup 129}I gas can reduce the process cost as bismuth is cheap. Further study is going on to improve the mechanical property of granular porous bismuths for their easy handling.

Iodine Gas Trapping using Granular Porous Bismuth

International Nuclear Information System (INIS)

Yang, Jae Hwan; Shin, Jin Myeong; Park, Jang Jin; Park, Geun Il; Yim, Mansung

2014-01-01

129 I is a radionuclide with a very long half-life of 1.57 Χ 10 7 years and has negative health effects to the human body. Therefore, the emission of 129 I into the air is closely regulated by the Environmental Protection Agency (EPA). Many methods for trapping gaseous 129 I have been developed thus far, including wet scrubbing and adsorption using silver loaded zeolites. Although wet scrubbing can effectively remove iodine, it suffers from corrosion of the vessel due to high concentration of the scrubbing solution. Silver loaded zeolites also show effectiveness in capturing 129 I gas, yet weak thermal stability of physisorbed iodine remains a challenge. We studied a novel and facile method to trap iodine gas using bismuth. Granular bismuth having many pores was synthesized using bismuth nitrate and polyvinyl alcohol as a bismuth precursor and pore forming agent, respectively. Reaction of iodine and our samples resulted in an iodine capturing capacity of more than 2 times that of the commercial grade silver exchanged zeolite (AgX). Granular porous bismuths synthesized using bismuth nitrate and PVA show a promising performance in capturing iodine gas. The use of bismuth in trapping 129 I gas can reduce the process cost as bismuth is cheap. Further study is going on to improve the mechanical property of granular porous bismuths for their easy handling

Trapping radioactive ions

CERN Document Server

Kluge, Heinz-Jürgen

2004-01-01

Trapping devices for atomic and nuclear physics experiments with radioactive ions are becoming more and more important at accelerator facilities. While about ten years ago only one online Penning trap experiment existed, namely ISOLTRAP at ISOLDE/CERN, meanwhile almost every radioactive beam facility has installed or plans an ion trap setup. This article gives an overview on ion traps in the operation, construction or planing phase which will be used for fundamental studies with short-lived radioactive nuclides such as mass spectrometry, laser spectroscopy and nuclear decay spectroscopy. In addition, this article summarizes the use of gas cells and radiofrequency quadrupole (Paul) traps at different facilities as a versatile tool for ion beam manipulation like retardation, cooling, bunching, and cleaning.

Trapping radioactive ions

International Nuclear Information System (INIS)

Kluge, H.-J.; Blaum, K.

2004-01-01

Trapping devices for atomic and nuclear physics experiments with radioactive ions are becoming more and more important at accelerator facilities. While about ten years ago only one online Penning trap experiment existed, namely ISOLTRAP at ISOLDE/CERN, meanwhile almost every radioactive beam facility has installed or plans an ion trap setup. This article gives an overview on ion traps in the operation, construction or planing phase which will be used for fundamental studies with short-lived radioactive nuclides such as mass spectrometry, laser spectroscopy and nuclear decay spectroscopy. In addition, this article summarizes the use of gas cells and radiofrequency quadrupole (Paul) traps at different facilities as a versatile tool for ion beam manipulation like retardation, cooling, bunching, and cleaning

Aesthetic Refinements in Patients with Prominent Eyes.

Science.gov (United States)

Richter, Dirk F; Schwaiger, Nina; Wiedner, Maria

2015-12-01

The treatment of prominent eyes is still a challenging task. As well as the surgery, proper preoperative diagnosis differentiating between patients with and without Graves ophthalmopathy plays an important role. In functionally asymptomatic patients with Graves disease suffering from the aesthetic impairment of prominent eyes, the transpalpebral decompression by intraorbital fat removal technique has been proved to be reliable, effective, safe, and easily performed by a trained and experienced oculoplastic surgeon. This technique provides long-lasting results, leading to improvement not only in visual function but also in personal well-being and in the patient's social life, with a high benefit-to-risk ratio. The most powerful tool to treat the lower lid deformity and malar bags in patients without Graves disease is the subperiosteal midface lift. It shortens the lid-cheek junction and blends the retaining periorbital ligaments. Furthermore, it adds volume to the lower lid and gives a stable support. By the nature of the procedure, it also turns a negative into a positive vector. In experienced hands, Olivari's orbital decompression and Hester's midface lift are ideal options for the treatment of prominent eyes. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

All-optical atom trap trace analysis for rare krypton isotopes

Energy Technology Data Exchange (ETDEWEB)

Woelk, Pablo; Kohler, Markus; Sieveke, Carsten; Hebel, Simon; Sahling, Peter [Carl Friedrich von Weizsaecker Centre for Science and Peace Research, University of Hamburg (Germany); Becker, Christoph; Sengstock, Klaus [Institut fuer Laser-Physik, University of Hamburg (Germany)

2016-07-01

The isotope Krypton-85 is an excellent indicator for the detection of nuclear reprocessing activities. However, for the analysis of atmospheric air samples, sensitive measuring methods down to the single atom level are required because of the small concentrations. Furthermore, for a practical and effective detection of clandestine reprocessing, small sample sizes and a high sample throughput rate are desirable. Established methods using Atom Trap Trace Analysis (ATTA) allow high sensitivity but have a limited throughput of about 200 samples per year, since the vacuum chambers have to be flushed for several hours after each measurement to avoid cross contamination due to the RF-driven excitation of metastable states. Here we present an enhanced ATTA apparatus, which in contrast to the established methods, produces metastable Kr all-optically. This avoids cross contamination, therefore allowing a much higher throughput rate. The apparatus is based on a self-made VUV-lamp and a 2D-3D magneto-optical trap setup. In the 2D trap metastable krypton is produced and a beam of atoms is formed by Doppler-cooling simultaneously.

Brandburg Prominance, Namibia, Africa

Science.gov (United States)

1993-01-01

The Brandburg Prominance, Namibia (21.0S, 14.5E) is a round basaltic plug and is the highest feature (over 8,000 ft) in the country. Wind streaks on the surface of the coastal desert, aligned northeast to southwest, are the result of frequent sand storms. Coastal stratus clouds provide most of the life supporting moisture as fog droplets in this arid land where annual rainfall may be less than a quarter of an inch for decades at a time.

Effect of trap position on the efficiency of trapping in treelike scale-free networks

International Nuclear Information System (INIS)

Zhang Zhongzhi; Lin Yuan; Ma Youjun

2011-01-01

The conventional wisdom is that the role and impact of nodes on dynamical processes in scale-free networks are not homogenous, because of the presence of highly connected nodes at the tail of their power-law degree distribution. In this paper, we explore the influence of different nodes as traps on the trapping efficiency of the trapping problem taking place on scale-free networks. To this end, we study in detail the trapping problem in two families of deterministically growing scale-free networks with treelike structure: one family is non-fractal, the other is fractal. In the first part of this work, we attack a special case of random walks on the two network families with a perfect trap located at a hub, i.e. node with the highest degree. The second study addresses the case with trap distributed uniformly over all nodes in the networks. For these two cases, we compute analytically the mean trapping time (MTT), a quantitative indicator characterizing the trapping efficiency of the trapping process. We show that in the non-fractal scale-free networks the MTT for both cases follows different scalings with the network order (number of network nodes), implying that trap's position has a significant effect on the trapping efficiency. In contrast, it is presented that for both cases in the fractal scale-free networks, the two leading scalings exhibit the same dependence on the network order, suggesting that the location of trap has no essential impact on the trapping efficiency. We also show that for both cases of the trapping problem, the trapping efficiency is more efficient in the non-fractal scale-free networks than in their fractal counterparts.

Influence of trap location on the efficiency of trapping in dendrimers and regular hyperbranched polymers.

Science.gov (United States)

Lin, Yuan; Zhang, Zhongzhi

2013-03-07

The trapping process in polymer systems constitutes a fundamental mechanism for various other dynamical processes taking place in these systems. In this paper, we study the trapping problem in two representative polymer networks, Cayley trees and Vicsek fractals, which separately model dendrimers and regular hyperbranched polymers. Our goal is to explore the impact of trap location on the efficiency of trapping in these two important polymer systems, with the efficiency being measured by the average trapping time (ATT) that is the average of source-to-trap mean first-passage time over every staring point in the whole networks. For Cayley trees, we derive an exact analytic formula for the ATT to an arbitrary trap node, based on which we further obtain the explicit expression of ATT for the case that the trap is uniformly distributed. For Vicsek fractals, we provide the closed-form solution for ATT to a peripheral node farthest from the central node, as well as the numerical solutions for the case when the trap is placed on other nodes. Moreover, we derive the exact formula for the ATT corresponding to the trapping problem when the trap has a uniform distribution over all nodes. Our results show that the influence of trap location on the trapping efficiency is completely different for the two polymer networks. In Cayley trees, the leading scaling of ATT increases with the shortest distance between the trap and the central node, implying that trap's position has an essential impact on the trapping efficiency; while in Vicsek fractals, the effect of location of the trap is negligible, since the dominant behavior of ATT is identical, respective of the location where the trap is placed. We also present that for all cases of trapping problems being studied, the trapping process is more efficient in Cayley trees than in Vicsek fractals. We demonstrate that all differences related to trapping in the two polymer systems are rooted in their underlying topological structures.

Towards trapped antihydrogen

CERN Document Server

Jorgensen, L V; Bertsche, W; Boston, A; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Hangst, J S; Hayano, R S; Hydomako, R; Jenkins, M J; Kurchaninov, L; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Page, R D; Povilus, A; Robicheaux, F; Sarid, E; Silveira, D M; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

2008-01-01

Substantial progress has been made in the last few years in the nascent field of antihydrogen physics. The next big step forward is expected to be the trapping of the formed antihydrogen atoms using a magnetic multipole trap. ALPHA is a new international project that started to take data in 2006 at CERN’s Antiproton Decelerator facility. The primary goal of ALPHA is stable trapping of cold antihydrogen atoms to facilitate measurements of its properties. We discuss the status of the ALPHA project and the prospects for antihydrogen trapping.

Thermoluminescence study of the trapped charge at an alumina surface electrode in different dielectric barrier discharge regimes

Energy Technology Data Exchange (ETDEWEB)

Ambrico, P F; Ambrico, M; Dilecce, G; De Benedictis, S [Consiglio Nazionale delle Ricerche, Istituto di Metodologie Inorganiche e dei Plasmi UOS Bari-c/o Dipartimento di Chimica, Universita degli Studi di Bari ' Aldo Moro' , via Orabona, 4, 70126 Bari (Italy); Colaianni, A [Dipartimento di Geologia e Geofisica, Universita degli Studi di Bari ' Aldo Moro' , via Orabona, 4, 70126 Bari (Italy); Schiavulli, L, E-mail: paolofrancesco.ambrico@cnr.i [Dipartimento Interateneo di Fisica, Universita degli Studi di Bari ' Aldo Moro' , via Orabona, 4, 70126 Bari (Italy)

2010-08-18

In this study, the charge trapping effect in alumina dielectric surfaces has been deeply investigated by means of a dedicated dielectric barrier discharge apparatus in different discharge regimes and gas mixtures. This work further validates our previous findings in the case of air discharges in a filamentary regime. Long lasting charge trapping has been evidenced by ex situ thermoluminescence characterizations of alumina dielectric barrier plates exposed to a plasma. The density of trapped surface charges was found to be higher in the glow discharge with respect to pseudo-glow and filamentary regimes, and for all regimes the minimum trap activation temperature was 390 K and the trap energy was less than or around 1 eV. This implies that in the case of glow discharges a higher reservoir of electrons is present. Also, the effect was found to persist for several days after running the discharge.

Thermoluminescence study of the trapped charge at an alumina surface electrode in different dielectric barrier discharge regimes

International Nuclear Information System (INIS)

Ambrico, P F; Ambrico, M; Dilecce, G; De Benedictis, S; Colaianni, A; Schiavulli, L

2010-01-01

In this study, the charge trapping effect in alumina dielectric surfaces has been deeply investigated by means of a dedicated dielectric barrier discharge apparatus in different discharge regimes and gas mixtures. This work further validates our previous findings in the case of air discharges in a filamentary regime. Long lasting charge trapping has been evidenced by ex situ thermoluminescence characterizations of alumina dielectric barrier plates exposed to a plasma. The density of trapped surface charges was found to be higher in the glow discharge with respect to pseudo-glow and filamentary regimes, and for all regimes the minimum trap activation temperature was 390 K and the trap energy was less than or around 1 eV. This implies that in the case of glow discharges a higher reservoir of electrons is present. Also, the effect was found to persist for several days after running the discharge.

Two-species mixing in a nested Penning trap for antihydrogen trapping

International Nuclear Information System (INIS)

Ordonez, C. A.; Weathers, D. L.

2008-01-01

There exists an international quest to trap neutral antimatter in the form of antihydrogen for scientific study. One method that is being developed for trapping antihydrogen employs a nested Penning trap. Such a trap serves to mix positrons and antiprotons so as to produce low energy antihydrogen atoms. Mixing is achieved when the confinement volumes of the two species overlap one another. In the work presented here, a theoretical understanding of the mixing process is developed by analyzing a mixing scheme that was recently reported [G. Gabrielse et al., Phys. Rev. Lett. 100, 113001 (2008)]. The results indicate that positron space charge or collisions among antiprotons may substantially reduce the fraction of antiprotons that have an energy suitable for antihydrogen trapping

A STATISTICAL STUDY OF TRANSVERSE OSCILLATIONS IN A QUIESCENT PROMINENCE

Energy Technology Data Exchange (ETDEWEB)

Hillier, A. [Kwasan and Hida Observatories, Kyoto University, Kyoto 607-8471 (Japan); Morton, R. J. [Mathematics and Information Science, Northumbria University, Pandon Building, Camden Street, Newcastle upon Tyne NE1 8ST (United Kingdom); Erdélyi, R., E-mail: andrew@kwasan.kyoto-u.ac.jp [Solar Physics and Space Plasma Research Centre (SP2RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

2013-12-20

The launch of the Hinode satellite has allowed for seeing-free observations at high-resolution and high-cadence making it well suited to study the dynamics of quiescent prominences. In recent years it has become clear that quiescent prominences support small-amplitude transverse oscillations, however, sample sizes are usually too small for general conclusions to be drawn. We remedy this by providing a statistical study of transverse oscillations in vertical prominence threads. Over a 4 hr period of observations it was possible to measure the properties of 3436 waves, finding periods from 50 to 6000 s with typical velocity amplitudes ranging between 0.2 and 23 km s{sup –1}. The large number of observed waves allows the determination of the frequency dependence of the wave properties and derivation of the velocity power spectrum for the transverse waves. For frequencies less than 7 mHz, the frequency dependence of the velocity power is consistent with the velocity power spectra generated from observations of the horizontal motions of magnetic elements in the photosphere, suggesting that the prominence transverse waves are driven by photospheric motions. However, at higher frequencies the two distributions significantly diverge, with relatively more power found at higher frequencies in the prominence oscillations. These results highlight that waves over a large frequency range are ubiquitous in prominences, and that a significant amount of the wave energy is found at higher frequency.

A STATISTICAL STUDY OF TRANSVERSE OSCILLATIONS IN A QUIESCENT PROMINENCE

International Nuclear Information System (INIS)

Hillier, A.; Morton, R. J.; Erdélyi, R.

2013-01-01

The launch of the Hinode satellite has allowed for seeing-free observations at high-resolution and high-cadence making it well suited to study the dynamics of quiescent prominences. In recent years it has become clear that quiescent prominences support small-amplitude transverse oscillations, however, sample sizes are usually too small for general conclusions to be drawn. We remedy this by providing a statistical study of transverse oscillations in vertical prominence threads. Over a 4 hr period of observations it was possible to measure the properties of 3436 waves, finding periods from 50 to 6000 s with typical velocity amplitudes ranging between 0.2 and 23 km s –1 . The large number of observed waves allows the determination of the frequency dependence of the wave properties and derivation of the velocity power spectrum for the transverse waves. For frequencies less than 7 mHz, the frequency dependence of the velocity power is consistent with the velocity power spectra generated from observations of the horizontal motions of magnetic elements in the photosphere, suggesting that the prominence transverse waves are driven by photospheric motions. However, at higher frequencies the two distributions significantly diverge, with relatively more power found at higher frequencies in the prominence oscillations. These results highlight that waves over a large frequency range are ubiquitous in prominences, and that a significant amount of the wave energy is found at higher frequency

Testing on air cleaning systems: Testing of the components in-place tests

International Nuclear Information System (INIS)

Billard, F.; Brion, J.

1967-01-01

The reliability of air cleaning systems is dependent on testing they are submitted to. Although in-place tests are the most important as they act as final tests upon achieved plants, component tests are necessary too. They allow detection of defective units before they are installed, partition of unit defects from mounting defects and they are more sensitive. For similar reasons, material teats are most useful. The various tests are described, about aerosol filters for one part, iodine trap for the other. The checked features are: materials nature, units sizes, efficiency, air resistance, flammability, humidity resistance, temperature resistance, adsorbent friability, etc... On iodine trapping systems, small check traps, working by-pass with the main trap are periodically subjected to efficiency test. This control allow to cut down the in-place tests frequency, particularly when poisoning from organic vapours is to be feared. (authors) [fr

High-resolution magnetostratigraphic and biostratigraphic study of Ethiopian traps-related products in Oligocene sediments from the Indian Ocean

Science.gov (United States)

Touchard, Yannick; Rochette, Pierre; Aubry, Marie Pierre; Michard, Annie

2003-02-01

Volcanic traps correspond typically to aerial emissions of more than 10 6 km 3 of magma over 1 Myr periods. The potential global impact of such emissions makes the precise correlation of traps with the global magnetobiochronologic timescale an important task. Our study is focused on the Ethiopian traps which correspond to the birth of the Afar hotspot at the triple junction between the Red Sea, Aden Gulf and East-African rift. The Ethiopian traps have a significant acidic component (about 10% of the traps by volume) which enables more efficient stratospheric aerosol diffusion than for the main basaltic eruptions. Furthermore, a magnetostratigraphy is well established for the traps: traps activity began in Chron C11r.2r and ended in Chron C11r.1r or C10r, with well clustered 40Ar/ 39Ar ages at 30±0.5 Ma. Four tephra layers, marked by prominent magnetic susceptibility peaks, occur in Oligocene sections of sites from Ocean Drilling Program Leg 115, drilled in the southern Indian Ocean near Madingley Rise, 2600 km away from the Ethiopian traps. In order to demonstrate that these tephra layers are related to the Ethiopian traps, a high-resolution study of sites 709 and 711 was undertaken, involving magnetostratigraphy and nannofossil stratigraphy, together with isotopic and geochemical characterization of the tephra. Geochemical analyses and isotope ratios of the glass shards indicate the same acid continental source for these tephras which is compatible with the Ethiopian signature. Moreover, Hole 711A provides a reliable magnetostratigraphy for the Oligocene (Chrons 13-9). The tephra layers occur in the interval spanning Chrons C11n.2n-C11n.1n which agrees with the positions of acidic layers in the traps. Calcareous nannofossil stratigraphy confirms the magnetostratigraphic interpretation, with the NP23/24 zonal boundary occurring within the interval containing the tephra layers. Hole 709B supports the results from Hole 711A. Thus, the Ethiopian traps can be

Quiescent Prominences in the Era of ALMA. II. Kinetic Temperature Diagnostics

Science.gov (United States)

Gunár, Stanislav; Heinzel, Petr; Anzer, Ulrich; Mackay, Duncan H.

2018-01-01

We provide the theoretical background for diagnostics of the thermal properties of solar prominences observed by the Atacama Large Millimeter/submillimeter Array (ALMA). To do this, we employ the 3D Whole-Prominence Fine Structure (WPFS) model that produces synthetic ALMA-like observations of a complex simulated prominence. We use synthetic observations derived at two different submillimeter/millimeter (SMM) wavelengths—one at a wavelength at which the simulated prominence is completely optically thin and another at a wavelength at which a significant portion of the simulated prominence is optically thick—as if these were the actual ALMA observations. This allows us to develop a technique for an analysis of the prominence plasma thermal properties from such a pair of simultaneous high-resolution ALMA observations. The 3D WPFS model also provides detailed information about the distribution of the kinetic temperature and the optical thickness along any line of sight. We can thus assess whether the measure of the kinetic temperature derived from observations accurately represents the actual kinetic temperature properties of the observed plasma. We demonstrate here that in a given pixel the optical thickness at the wavelength at which the prominence plasma is optically thick needs to be above unity or even larger to achieve a sufficient accuracy of the derived information about the kinetic temperature of the analyzed plasma. Information about the optical thickness cannot be directly discerned from observations at the SMM wavelengths alone. However, we show that a criterion that can identify those pixels in which the derived kinetic temperature values correspond well to the actual thermal properties in which the observed prominence can be established.

Skating on a Film of Air: Drops Impacting on a Surface

Science.gov (United States)

Kolinski, John M.; Rubinstein, Shmuel M.; Mandre, Shreyas; Brenner, Michael P.; Weitz, David A.; Mahadevan, L.

2012-02-01

The commonly accepted description of drops impacting on a surface typically ignores the essential role of the air that is trapped between the impacting drop and the surface. Here we describe a new imaging modality that is sensitive to the behavior right at the surface. We show that a very thin film of air, only a few tens of nanometers thick, remains trapped between the falling drop and the surface as the drop spreads. The thin film of air serves to lubricate the drop enabling the fluid to skate on the air film laterally outward at surprisingly high velocities, consistent with theoretical predictions. Eventually this thin film of air breaks down as the fluid wets the surface via a spinodal-like mechanism. Our results show that the dynamics of impacting drops are much more complex than previously thought, with a rich array of unexpected phenomena that require rethinking classic paradigms.

Dynamic analysis of trapping and escaping in dual beam optical trap

Science.gov (United States)

Li, Wenqiang; Hu, Huizhu; Su, Heming; Li, Zhenggang; Shen, Yu

2016-10-01

In this paper, we simulate the dynamic movement of a dielectric sphere in optical trap. This dynamic analysis can be used to calibrate optical forces, increase trapping efficiency and measure viscous coefficient of surrounding medium. Since an accurate dynamic analysis is based on a detailed force calculation, we calculate all forces a sphere receives. We get the forces of dual-beam gradient radiation pressure on a micron-sized dielectric sphere in the ray optics regime and utilize Einstein-Ornstein-Uhlenbeck to deal with its Brownian motion forces. Hydrodynamic viscous force also exists when the sphere moves in liquid. Forces from buoyance and gravity are also taken into consideration. Then we simulate trajectory of a sphere when it is subject to all these forces in a dual optical trap. From our dynamic analysis, the sphere can be trapped at an equilibrium point in static water, although it permanently fluctuates around the equilibrium point due to thermal effects. We go a step further to analyze the effects of misalignment of two optical traps. Trapping and escaping phenomena of the sphere in flowing water are also simulated. In flowing water, the sphere is dragged away from the equilibrium point. This dragging distance increases with the decrease of optical power, which results in escaping of the sphere with optical power below a threshold. In both trapping and escaping process we calculate the forces and position of the sphere. Finally, we analyze a trapping region in dual optical tweezers.

Fabrication of micro-prominences on PTFE surface using proton beam writing

Energy Technology Data Exchange (ETDEWEB)

Kitamura, Akane, E-mail: ogawa.akane@jaea.go.jp [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan); Satoh, Takahiro; Koka, Masashi [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan); Kobayashi, Tomohiro [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 350-0198 (Japan); Kamiya, Tomihiro [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan)

2013-07-01

Polytetrafluoroethylene (PTFE) is a typical fluoropolymer and it has several desirable technological properties such as electrical insulation, solid lubrication etc. However, the conventional microstructuring methods have not been well applied to PTFE due to its chemical inertness. Some effective micromachining using synchrotron radiation or ion beam irradiation has been reported. In this study, we create micro-prominences by raising the original surface using proton beam writing (PBW) without chemical etching. A conical prominence was formed by spiral drawing from the center with a 3 MeV proton beam. The body was porous, and the bulk PTFE below the prominence changed to fragmented structures. With decreasing writing speed, the prominence became taller but the height peaked. The prominence gradually reduced in size after the speed reached the optimum value. We expect that these porous projections with high aspect ratio will be versatile in medical fields and microelectromechanical systems (MEMS) technology.

Deuterium trapping in tungsten

Science.gov (United States)

Poon, Michael

Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation. Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies. Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation. The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D2 molecules inside the void with a trap energy of 1.2 eV. Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D

Deuterium trapping in tungsten

International Nuclear Information System (INIS)

Poon, M.

2004-01-01

Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies. . Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D 2 molecules inside the void with a trap energy of 1.2 eV. . Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D

Deuterium trapping in tungsten

Energy Technology Data Exchange (ETDEWEB)

Poon, M

2004-07-01

Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies. . Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D{sub 2} molecules inside the void with a trap energy of 1.2 eV. . Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D

Status and outlook of CHIP-TRAP: The Central Michigan University high precision Penning trap

Science.gov (United States)

Redshaw, M.; Bryce, R. A.; Hawks, P.; Gamage, N. D.; Hunt, C.; Kandegedara, R. M. E. B.; Ratnayake, I. S.; Sharp, L.

2016-06-01

At Central Michigan University we are developing a high-precision Penning trap mass spectrometer (CHIP-TRAP) that will focus on measurements with long-lived radioactive isotopes. CHIP-TRAP will consist of a pair of hyperbolic precision-measurement Penning traps, and a cylindrical capture/filter trap in a 12 T magnetic field. Ions will be produced by external ion sources, including a laser ablation source, and transported to the capture trap at low energies enabling ions of a given m / q ratio to be selected via their time-of-flight. In the capture trap, contaminant ions will be removed with a mass-selective rf dipole excitation and the ion of interest will be transported to the measurement traps. A phase-sensitive image charge detection technique will be used for simultaneous cyclotron frequency measurements on single ions in the two precision traps, resulting in a reduction in statistical uncertainty due to magnetic field fluctuations.

Evaluation method for acoustic trapping performance by tracking motion of trapped microparticle

Science.gov (United States)

Lim, Hae Gyun; Ham Kim, Hyung; Yoon, Changhan

2018-05-01

We report a method to evaluate the performances of a single-beam acoustic tweezer using a high-frequency ultrasound transducer. The motion of a microparticle trapped by a 45-MHz single-element transducer was captured and analyzed to deduce the magnitude of trapping force. In the proposed method, the motion of a trapped microparticle was analyzed from a series of microscopy images to compute trapping force; thus, no additional equipment such as microfluidics is required. The method could be used to estimate the effective trapping force in an acoustic tweezer experiment to assess cell membrane deformability by attaching a microbead to the surface of a cell and tracking the motion of the trapped bead, which is similar to a bead-based assay that uses optical tweezers. The results showed that the trapping force increased with increasing acoustic intensity and duty factor, but the force eventually reached a plateau at a higher acoustic intensity. They demonstrated that this method could be used as a simple tool to evaluate the performance and to optimize the operating conditions of acoustic tweezers.

Toward a better understanding of the impact of mass transit air pollutants on human health.

Science.gov (United States)

Kim, Ki-Hyun; Kumar, Pawan; Szulejko, Jan E; Adelodun, Adedeji A; Junaid, Muhammad Faisal; Uchimiya, Minori; Chambers, Scott

2017-05-01

Globally, modern mass transport systems whether by road, rail, water, or air generate airborne pollutants in both developing and developed nations. Air pollution is the primary human health concern originating from modern transportation, particularly in densely-populated urban areas. This review will specifically focus on the origin and the health impacts of carbonaceous traffic-related air pollutants (TRAP), including particulate matter (PM), volatile organic compounds (VOCs), and elemental carbon (EC). We conclude that the greatest current challenge regarding urban TRAP is understanding and evaluating the human health impacts well enough to set appropriate pollution control measures. Furthermore, we provide a detailed discussion regarding the effects of TRAP on local environments and pedestrian health in low and high traffic-density environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Atmospheric H2O2 measurement: comparison of cold trap method with impinger bubbling method

Science.gov (United States)

Sakugawa, H.; Kaplan, I. R.

1987-01-01

Collection of atmospheric H2O2 was performed by a cold trap method using dry ice-acetone as the refrigerant. The air was drawn by a pump into a glass gas trap immersed in the dry ice-acetone slush in a dewar flask at a flow rate of 2.5 l min-1 for approximately 2 h. Collection efficiency was > 99% and negligible interferences by O3, SO2 or organic matter with the collected H2O2 in the trap were observed. This method was compared with the air impinger bubbling method which has been previously described (Kok et al., 1978a, b, Envir. Sci. Technol. 12, 1072-1080). The measured total peroxide (H2O2 + organic peroxide) values in a series of aim samples collected by the impinger bubbling method (0.06-3.7 ppb) were always higher than those obtained by the cold trap method (0.02-1.2 ppb). Laboratory experiments suggest that the difference in values between the two methods probably results from the aqueous phase generation of H2O2 and organic peroxide in the impinger solution by a reaction of atmospheric O3 with olefinic and aromatic compounds. If these O3-organic compound reactions which occur in the impinger also occur in aqueous droplets in the atmosphere, the process could be very important for aqueous phase generation of H2O2 in clouds and rainwater.

Calcium Atom Trap for Atom Trap Mass Spectrometer

Energy Technology Data Exchange (ETDEWEB)

Ko, Kwang Hoon; Park, Hyun Min; Han, Jae Min; Kim, Taek Soo; Cha, Yong Ho; Lim, Gwon; Jeong, Do Young [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-05-15

Trace isotope analysis has been an important role in science, archaeological dating, geology, biology and nuclear industry. Artificially produced fission products such as Sr-90, Cs-135 and Kr-85 can be released to the environment when nuclear accident occurs and the reprocessing factory operates. Thus, the analysis of them has been of interest in nuclear industry. But it is difficult to detect them due to low natural abundance less then 10-10. The ultra-trace radio isotopes have been analyzed by the radio-chemical method, accelerator mass spectrometer, and laser based method. The radiochemical method has been used in the nuclear industry. But this method has disadvantages of long measurement time for long lived radioisotopes and toxic chemical process for the purification. The accelerator mass spectrometer has high isotope selectivity, but the system is huge and it has the isobar effects. The laser based method, such as RIMS (Resonance Ionization Mass Spectrometry) is a basically isobar-effect free method. Recently, ATTA (Atom Trap Trace Analysis), one of the laser based method, has been successfully demonstrated sufficient isotope selectivity with small system size. It has been applied for the detection of Kr-81 and Kr-85. However, it is not suitable for real sample detection, because it requires steady atomic beam generation during detection and is not allowed simultaneous detection of other isotopes. Therefore, we proposed the coupled method of Atom Trap and Mass Spectrometer. It consists of three parts, neutral atom trap, ionization and mass spectrometer. In this paper, we present the demonstration of the magneto-optical trap of neutral calcium. We discuss the isotope selective characteristics of the MOT (Magneto Optical Trap) of calcium by the fluorescence measurement. In addition, the frequency stabilization of the trap beam will be presented

ARE TORNADO-LIKE MAGNETIC STRUCTURES ABLE TO SUPPORT SOLAR PROMINENCE PLASMA?

Energy Technology Data Exchange (ETDEWEB)

Luna, M.; Moreno-Insertis, F. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Priest, E. [Mathematics Institute, University of St Andrews, St Andrews KY16 9SS (United Kingdom)

2015-07-20

Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloidal flows are present.

ARE TORNADO-LIKE MAGNETIC STRUCTURES ABLE TO SUPPORT SOLAR PROMINENCE PLASMA?

International Nuclear Information System (INIS)

Luna, M.; Moreno-Insertis, F.; Priest, E.

2015-01-01

Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloidal flows are present

Are Tornado-Like Magnetic Structures Able to Support Solar Prominence Plasma?

Science.gov (United States)

Ogunjo, S. T.; Luna Bennasar, M.; Moreno-Insertis, F.; Priest, E. R.

2015-12-01

Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloidal flows are present.

Unintended exposure in radiotherapy: Identification of prominent causes

International Nuclear Information System (INIS)

Boadu, Mary; Rehani, Madan Mohan

2009-01-01

Background and purpose: Unintended exposures in radiotherapy are likely to occur when certain conditions that favour such exposures exist. Based on the frequency of occurrence of various causes of 100 events of unintended exposures in radiotherapy as derived from the analysis of published reports, a checklist for assessing the vulnerability of radiotherapy facilities for potential accidents has been prepared. The list presents items to be considered for safety critical assessments of a radiotherapy department for the improvement of patient safety and the entire radiotherapy processes. Materials and methods: The resources used for this paper consist of 100 unintended radiotherapy exposures and were derived from existing published reports. The analysis was performed by forming two templates: one consisting of 10 initiating events and another of 35 contributing factors. Results: Four most prominent initiating events were identified and together accounted for about 70% of all the unintended exposure events. Ten most prominent contributing factors were also identified and together accounted for about 70% of all the radiotherapy unintended exposure events covered under this study. Conclusion: With this knowledge of high frequency of occurrences, the identified four prominent initiating events and the 10 most prominent contributing factors must be checked and dealt with as a matter of priority when assessing the safety of a radiotherapy facility. A simple checklist for checking the quality assurance programmes of a radiotherapy department for every aspect of the design and delivery of radiation have been provided.

A live-trap and trapping technique for fossorial mammals

African Journals Online (AJOL)

mammals. G.C. Hickman. An effective live-trap was designed for Cryptomys hottentotus .... that there is an animal in the burrow system, and to lessen the likelihood of the .... the further testing and modification of existing trap types. Not only is it ...

Case Study: Trap Crop with Pheromone Traps for Suppressing Euschistus servus (Heteroptera: Pentatomidae in Cotton

Directory of Open Access Journals (Sweden)

P. G. Tillman

2012-01-01

Full Text Available The brown stink bug, Euschistus servus (Say, can disperse from source habitats, including corn, Zea mays L., and peanut, Arachis hypogaea L., into cotton, Gossypium hirsutum L. Therefore, a 2-year on-farm experiment was conducted to determine the effectiveness of a sorghum (Sorghum bicolor (L. Moench spp. bicolor trap crop, with or without Euschistus spp. pheromone traps, to suppress dispersal of this pest to cotton. In 2004, density of E. servus was lower in cotton fields with sorghum trap crops (with or without pheromone traps compared to control cotton fields. Similarly, in 2006, density of E. servus was lower in cotton fields with sorghum trap crops and pheromone traps compared to control cotton fields. Thus, the combination of the sorghum trap crop and pheromone traps effectively suppressed dispersal of E. servus into cotton. Inclusion of pheromone traps with trap crops potentially offers additional benefits, including: (1 reducing the density of E. servus adults in a trap crop, especially females, to possibly decrease the local population over time and reduce the overwintering population, (2 reducing dispersal of E. servus adults from the trap crop into cotton, and (3 potentially attracting more dispersing E. servus adults into a trap crop during a period of time when preferred food is not prevalent in the landscape.

Angular trap for macroparticles

International Nuclear Information System (INIS)

Aksyonov, D.S.

2013-01-01

Properties of angular macroparticle traps were investigated in this work. These properties are required to design vacuum arc plasma filters. The correlation between trap geometry parameters and its ability to absorb macroparticles were found. Calculations allow one to predict the behaviour of filtering abilities of separators which contain such traps in their design. Recommendations regarding the use of angular traps in filters of different builds are given.

Trapped antihydrogen

Energy Technology Data Exchange (ETDEWEB)

Butler, E., E-mail: eoin.butler@cern.ch [CERN, Physics Department (Switzerland); Andresen, G. B. [Aarhus University, Department of Physics and Astronomy (Denmark); Ashkezari, M. D. [Simon Fraser University, Department of Physics (Canada); Baquero-Ruiz, M. [University of California, Department of Physics (United States); Bertsche, W. [Swansea University, Department of Physics (United Kingdom); Bowe, P. D. [Aarhus University, Department of Physics and Astronomy (Denmark); Cesar, C. L. [Universidade Federal do Rio de Janeiro, Instituto de Fisica (Brazil); Chapman, S. [University of California, Department of Physics (United States); Charlton, M.; Deller, A.; Eriksson, S. [Swansea University, Department of Physics (United Kingdom); Fajans, J. [University of California, Department of Physics (United States); Friesen, T.; Fujiwara, M. C. [University of Calgary, Department of Physics and Astronomy (Canada); Gill, D. R. [TRIUMF (Canada); Gutierrez, A. [University of British Columbia, Department of Physics and Astronomy (Canada); Hangst, J. S. [Aarhus University, Department of Physics and Astronomy (Denmark); Hardy, W. N. [University of British Columbia, Department of Physics and Astronomy (Canada); Hayden, M. E. [Simon Fraser University, Department of Physics (Canada); Humphries, A. J. [Swansea University, Department of Physics (United Kingdom); Collaboration: ALPHA Collaboration; and others

2012-12-15

Precision spectroscopic comparison of hydrogen and antihydrogen holds the promise of a sensitive test of the Charge-Parity-Time theorem and matter-antimatter equivalence. The clearest path towards realising this goal is to hold a sample of antihydrogen in an atomic trap for interrogation by electromagnetic radiation. Achieving this poses a huge experimental challenge, as state-of-the-art magnetic-minimum atom traps have well depths of only {approx}1 T ({approx}0.5 K for ground state antihydrogen atoms). The atoms annihilate on contact with matter and must be 'born' inside the magnetic trap with low kinetic energies. At the ALPHA experiment, antihydrogen atoms are produced from antiprotons and positrons stored in the form of non-neutral plasmas, where the typical electrostatic potential energy per particle is on the order of electronvolts, more than 10{sup 4} times the maximum trappable kinetic energy. In November 2010, ALPHA published the observation of 38 antiproton annihilations due to antihydrogen atoms that had been trapped for at least 172 ms and then released-the first instance of a purely antimatter atomic system confined for any length of time (Andresen et al., Nature 468:673, 2010). We present a description of the main components of the ALPHA traps and detectors that were key to realising this result. We discuss how the antihydrogen atoms were identified and how they were discriminated from the background processes. Since the results published in Andresen et al. (Nature 468:673, 2010), refinements in the antihydrogen production technique have allowed many more antihydrogen atoms to be trapped, and held for much longer times. We have identified antihydrogen atoms that have been trapped for at least 1,000 s in the apparatus (Andresen et al., Nature Physics 7:558, 2011). This is more than sufficient time to interrogate the atoms spectroscopically, as well as to ensure that they have relaxed to their ground state.

Piecewise mass flows within a solar prominence observed by the New Vacuum Solar Telescope

Science.gov (United States)

Li, Hongbo; Liu, Yu; Tam, Kuan Vai; Zhao, Mingyu; Zhang, Xuefei

2018-06-01

The material of solar prominences is often observed in a state of flowing. These mass flows (MF) are important and useful for us to understand the internal structure and dynamics of prominences. In this paper, we present a high resolution Hα observation of MFs within a quiescent solar prominence. From the observation, we find that the plasma primarily has a circular motion and a downward motion separately in the middle section and legs of the prominence, which creates a piecewise mass flow along the observed prominence. Moreover, the observation also shows a clear displacement of MF's velocity peaks in the middle section of the prominence. All of these provide us with a detailed record of MFs within a solar prominence and show a new approach to detecting the physical properties of prominence.

Cylindrical prominences and the magnetic influence of the photospheric boundary

International Nuclear Information System (INIS)

Lerche, I.; Chicago Univ., IL; Low, B.C.

1980-01-01

We construct exact, non-linear, solutions for an horizontal, cylindrical, current-carrying, prominence supported against solar gravity by the action of a Lorentz force. The solutions incorporate the photosphere boundary condition, proposed by van Tend and Kuperus (1978), and analyzed by them for line filaments. Our solutions have finite radius for the prominence material and, as well as satisfying the equations of magnetostatic equilibrium, they allow for the continuity of gas pressure, and of the normal and tangential components of magnetic field across the circular prominence boundary. We show that an infinity of solutions is possible and we illustrate the basic behavior by investigation of a special case. We also give a prescription for constructing equilibrium fields for any horizontal prominence with arbitrary cross-section and with an arbitrary external magnetic field. The prescription is ideally suited for numerical codes and we suggest that both the equilibrium of such shapes can easily be accomplished numerically together with their evolutionary history. (orig.)

Optimization of multifunnel traps for emerald ash borer (Coleoptera: Buprestidae): influence of size, trap coating, and color.

Science.gov (United States)

Francese, Joseph A; Rietz, Michael L; Mastro, Victor C

2013-12-01

Field assays were conducted in southeastern and south-central Michigan in 2011 and 2012 to optimize green and purple multifunnel (Lindgren funnel) traps for use as a survey tool for the emerald ash borer, Agrilus planipennis Fairmaire. Larger sized (12- and 16-unit) multifunnel traps caught more beetles than their smaller-sized (4- and 8-unit) counterparts. Green traps coated with untinted (white) fluon caught almost four times as many adult A. planipennis as Rain-X and tinted (green) fluon-coated traps and almost 33 times more beetles than untreated control traps. Purple multifunnel traps generally caught much lower numbers of A. planipennis adults than green traps, and trap catch on them was not affected by differences in the type of coating applied. However, trap coating was necessary as untreated control purple traps caught significantly less beetles than traps treated with Rain-X and untinted or tinted (purple) fluon. Proportions of male beetles captured were generally much higher on green traps than on purple traps, but sex ratios were not affected by trap coating. In 2012, a new shade of purple plastic, based on a better color match to an attractive purple paint than the previously used purple, was used for trapping assays. When multifunnel traps were treated with fluon, green traps caught more A. planipennis adults than both shades of purple and a prism trap that was manufactured based on the same color match. Trap catch was not affected by diluting the fluon concentration applied to traps to 50% (1:1 mixture in water). At 10%, trap catch was significantly lowered.

Status of THe-Trap

Energy Technology Data Exchange (ETDEWEB)

Streubel, Sebastian; Eronen, Tommi; Hoecker, Martin; Ketter, Jochen; Blaum, Klaus [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Van Dyck, Robert S. Jr. [Department of Physics, University of Washington, Seattle, WA (United States)

2013-07-01

THe-Trap (short for Tritium-{sup 3}He Trap) is a Penning-trap setup dedicated to measure the {sup 3}H to {sup 3}He mass-ratio with a relative uncertainty of better than 10{sup -11}. The ratio is of relevance for the KArlsruhe TRItium Neutrino experiment (KATRIN), which aims to measure the electron anti-neutrino mass, by measuring the shape of the β-decay energy spectrum close to its endpoint. An independent measurement of the {sup 3}H to {sup 3}He mass-ratio pins down this endpoint, and thus will help to determine the systematics of KATRIN. The trap setup consists of two Penning-traps: One trap for precision measurements, the other trap for ion storage. Ideally, the trap content will be periodically switched, which reduces the time between the measurements of the two ions' motional frequencies. In 2012, a mass ratio measurement of {sup 12}C{sup 4+} to {sup 14}N{sup 5+} was performed to characterize systematic effects of the traps. This measurement yielded a accuracy of 10{sup -9}. Further investigations revealed that a major reason for the modest accuracy is the large axial amplitude of ∼100 μm, compared to a ideal case of 3 μm at 4 K. In addition, relative magnetic fluctuations at a 3 x 10{sup -10} level on a 10 h timescale need to be significantly improved. In this contribution, the aforementioned findings and further systematic studies will be presented.

The most prominent safety guarantees

International Nuclear Information System (INIS)

Lucenet, G.

1978-01-01

The Creys-Malville Nuclear Centre has been designed using the safety analysis implemented since the beginning of the developments of breeder reactors in France and the Super Phenix follows almost the same safety regulations as its predecessor the Phenix reactor. These regulations are based on: 'Recommendations for the safety standards of the Super Phenix' drawn up by the French Safety Authorities in July 1973. The prominent points are summarised. (C.F.)

A Discourse Perspective of Topic-prominence in Chinese EFL Learners’ Interlanguage

Directory of Open Access Journals (Sweden)

Shaopeng Li

2014-07-01

Full Text Available The present study aims to investigate the general characteristics of topic-prominent typological interlanguage development of Chinese learners of English in terms of acquiring subject-prominent English structures from the discourse perspective. We have selected as the research target “topic chain” which is the main topic-prominent structure in Chinese discourse and “zero anaphora” which is the most common topic anaphor of topic chain. Topic structures mainly appear in Chinese discourse in the form of “topic chain” (Wang, 2002; 2004. Actually, in the event of a topic chain, research on topic structures should go into the typical range of discourse. Two important findings were yielded by the present study. First, the characteristics of Chinese topic chain are transferrable to the interlanguage of Chinese EFL learners, thus resulting in overgeneralization of zero anaphora; second, interlanguage discourse of Chinese EFL learners reflects the characteristics of a second language acquisition process from topic-prominence to subject-prominence, thus lending support to the discourse transfer hypothesis.

Air-Sea Interaction

Science.gov (United States)

Csanady, G. T.

2001-03-01

In recent years air-sea interaction has emerged as a subject in its own right, encompassing small-scale and large-scale processes in both air and sea. Air-Sea Interaction: Laws and Mechanisms is a comprehensive account of how the atmosphere and the ocean interact to control the global climate, what physical laws govern this interaction, and its prominent mechanisms. The topics covered range from evaporation in the oceans, to hurricanes, and on to poleward heat transport by the oceans. By developing the subject from basic physical (thermodynamic) principles, the book is accessible to graduate students and research scientists in meteorology, oceanography, and environmental engineering. It will also be of interest to the broader physics community involved in the treatment of transfer laws, and thermodynamics of the atmosphere and ocean.

Prominence Bubbles and Plumes: Thermo-magnetic Buoyancy in Coronal Cavity Systems

Science.gov (United States)

Berger, Thomas; Hurlburt, N.

2009-05-01

The Hinode/Solar Optical Telescope continues to produce high spatial and temporal resolution images of solar prominences in both the Ca II 396.8 nm H-line and the H-alpha 656.3 nm line. Time series of these images show that many quiescent prominences produce large scale (50 Mm) dark "bubbles" that "inflate" into, and sometimes burst through, the prominence material. In addition, small-scale (2--5 Mm) dark plumes are seen rising into many quiescent prominences. We show typical examples of both phenomena and argue that they originate from the same mechanism: concentrated and heated magnetic flux that rises due to thermal and magnetic buoyancy to equilibrium heights in the prominence/coronal-cavity system. More generally, these bubbles and upflows offer a source of both magnetic flux and mass to the overlying coronal cavity, supporting B.C. Low's theory of CME initiation via steadily increasing magnetic buoyancy breaking through the overlying helmut streamer tension forces. Quiescent prominences are thus seen as the lowermost parts of the larger coronal cavity system, revealing through thermal effects both the cooled downflowing "drainage" from the cavity and the heated upflowing magnetic "plasmoids" supplying the cavity. We compare SOT movies to new 3D compressible MHD simulations that reproduce the dark turbulent plume dynamics to establish the magnetic and thermal character of these buoyancy-driven flows into the corona.

Toll-like receptor 4 in glial inflammatory responses to air pollution in vitro and in vivo.

Science.gov (United States)

Woodward, Nicholas C; Levine, Morgan C; Haghani, Amin; Shirmohammadi, Farimah; Saffari, Arian; Sioutas, Constantinos; Morgan, Todd E; Finch, Caleb E

2017-04-14

Exposure to traffic-related air pollution (TRAP) is associated with accelerated cognitive aging and higher dementia risk in human populations. Rodent brains respond to TRAP with activation of astrocytes and microglia, increased inflammatory cytokines, and neurite atrophy. A role for Toll-like receptor 4 (TLR4) was suggested in mouse TLR4-knockouts, which had attenuated lung macrophage responses to air pollution. To further analyze these mechanisms, we examined mixed glial cultures (astrocytes and microglia) for RNA responses to nanoscale particulate matter (nPM; diameter brain inflammatory responses to air pollution, and warrant further study of TLR4 in accelerated cognitive aging by air pollution.

Modeling of prominence threads in magnetic fields: Levitation by incompressible MHD waves

Science.gov (United States)

Pécseli, Hans; Engvold, OddbjØrn

2000-05-01

The nature of thin, highly inclined threads observed in quiescent prominences has puzzled solar physicists for a long time. When assuming that the threads represent truly inclined magnetic fields, the supporting mechanism of prominence plasma against gravity has remained an open issue. This paper examines the levitation of prominence plasma exerted by weakly damped MHD waves in nearly vertical magnetic flux tubes. It is shown that the wave damping, and resulting `radiation pressure', caused predominantly by ion-neutral collisions in the `cold' prominence plasma, may balance the acceleration of gravity provided the oscillation frequency is ω~ 2 rad s^-1 (f~0.5 Hz). Such short wave periods may be the result of small-scale magnetic reconnections in the highly fragmentary magnetic field of quiescent prominences. In the proposed model, the wave induced levitation acts predominantly on plasma - neutral gas mixtures.

Automatic detection of prominence (as defined by listeners' judgements) in read aloud Dutch sentences

NARCIS (Netherlands)

Streefkerk, B.M.; Pols, L.C.W.; ten Bosch, L.F.M.

1998-01-01

This paper describes a first step towards the automatic classification of prominence (as defined by native listeners). As a result of a listening experiment each word in 500 sentences was marked with a rating scale between `0' (non-prominent) and `10' (very prominent). These prominence labels are

Search For Trapped Antihydrogen

CERN Document Server

Andresen, Gorm B.; Baquero-Ruiz, Marcelo; Bertsche, William; Bowe, Paul D.; Bray, Crystal C.; Butler, Eoin; Cesar, Claudio L.; Chapman, Steven; Charlton, Michael; Fajans, Joel; Friesen, Tim; Fujiwara, Makoto C.; Gill, David R.; Hangst, Jeffrey S.; Hardy, Walter N.; Hayano, Ryugo S.; Hayden, Michael E.; Humphries, Andrew J.; Hydomako, Richard; Jonsell, Svante; Jorgensen, Lars V.; Kurchaninov, Lenoid; Lambo, Ricardo; Madsen, Niels; Menary, Scott; Nolan, Paul; Olchanski, Konstantin; Olin, Art; Povilus, Alexander; Pusa, Petteri; Robicheaux, Francis; Sarid, Eli; Nasr, Sarah Seif El; Silveira, Daniel M.; So, Chukman; Storey, James W.; Thompson, Robert I.; van der Werf, Dirk P.; Wilding, Dean; Wurtele, Jonathan S.; Yamazaki, Yasunori

2011-01-01

We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ~30 ms. After a three-week experimental run in 2009 involving mixing of 10^7 antiprotons with 1.3 10^9 positrons to produce 6 10^5 antihydrogen atoms, we have identified six antiproton annihilation events that are consist...

Injection into electron plasma traps

International Nuclear Information System (INIS)

Gorgadze, Vladimir; Pasquini, Thomas A.; Fajans, Joel; Wurtele, Jonathan S.

2003-01-01

Computational studies and experimental measurements of plasma injection into a Malmberg-Penning trap reveal that the number of trapped particles can be an order of magnitude higher than predicted by a simple estimates based on a ballistic trapping model. Enhanced trapping is associated with a rich nonlinear dynamics generated by the space-charge forces of the evolving trapped electron density. A particle-in-cell simulation is used to identify the physical mechanisms that lead to the increase in trapped electrons. The simulations initially show strong two-stream interactions between the electrons emitted from the cathode and those reflected off the end plug of the trap. This is followed by virtual cathode oscillations near the injection region. As electrons are trapped, the initially hollow longitudinal phase-space is filled, and the transverse radial density profile evolves so that the plasma potential matches that of the cathode. Simple theoretical arguments are given that describe the different dynamical regimes. Good agreement is found between simulation and theory

[Trapping techniques for Solenopsis invicta].

Science.gov (United States)

Liang, Xiao-song; Zhang, Qiang; Zhuang, Yiong-lin; Li, Gui-wen; Ji, Lin-peng; Wang, Jian-guo; Dai, Hua-guo

2007-06-01

A field study was made to investigate the trapping effects of different attractants, traps, and wind directions on Solenopsis invicta. The results showed that among the test attractants, TB1 (50 g fishmeal, 40 g peptone, 10 ml 10% sucrose water solution and 20 ml soybean oil) had the best effect, followed by TB2 (ham), TB6 (100 g cornmeal and 20 ml soybean oil) and TB4 (10 ml 10% sucrose water solution, 100 g sugarcane powder and 20 ml soybean oil), with a mean capture efficiency being 77.6, 58.7, 29 and 7.7 individuals per trap, respectively. No S. invicta was trapped with TB3 (10 ml 10% sucrose water solution, 100 g cornmeal and 20 ml soybean oil) and TB5 (honey). Tube trap was superior to dish trap, with a trapping efficiency of 75.2 and 35 individuals per trap, respectively. The attractants had better effects in leeward than in windward.

Separation of effects of oxide-trapped charge and interface-trapped charge on mobility in irradiated power MOSFETs

International Nuclear Information System (INIS)

Zupac, D.; Galloway, K.F.; Khosropour, P.; Anderson, S.R.; Schrimpf, R.D.

1993-01-01

An effective approach to separating the effects of oxide-trapped charge and interface-trapped charge on mobility degradation in irradiated MOSFETs is demonstrated. It is based on analyzing mobility data sets which have different functional relationships between the radiation-induced-oxide-trapped charge and interface-trapped charge. Separation of effects of oxide-trapped charge and interface-trapped charge is possible only if these two trapped charge components are not linearly dependent. A significant contribution of oxide-trapped charge to mobility degradation is demonstrated and quantified

Droplet Impacting on Liquid Film: Evolution of Entrapped Air Layer

Science.gov (United States)

Tang, Xiaoyu; Saha, Abhishek; Law, Chung K.

2014-11-01

In this work we experimentally studied the dynamics of droplet impacting films of various thicknesses within a range of h / R <= 1 (h: film thickness; R: droplet radius). High speed imaging and color interferometry enabled the investigation of the evolution of the air layer trapped between two surfaces, which plays a critical role in determining the collision outcome. Globally, two distinct regimes of impaction outcome, namely bouncing and merging, are observed at low and high impact inertia, respectively. Impaction with high inertia depletes the air layer before the droplet significantly deforms, resulting in permanent merging. At low impact inertia, however, color interferometry shows the existence of three phases prior to bouncing. Upon impaction, droplet endures significant deformation trapping the air layer between the interfaces, hence increasing the resistance force. This phase is characterized by fast deformation of the air film, followed by a period of pseudo equilibrium, with minimal changes in the interfacial air-film profile. The droplet also lacks kinetic energy to penetrate further into the film, resulting in a temporary balance between the droplet weight and air-film pressure. The deformed droplet eventually relaxes towards spherical shape to destroy the equilibrium. Fast change occurs in air-layer and pressure distribution favoring the droplet bouncing.

Quantum Simulation of a Lattice Schwinger Model in a Chain of Trapped Ions

Directory of Open Access Journals (Sweden)

P. Hauke

2013-11-01

Full Text Available We discuss how a lattice Schwinger model can be realized in a linear ion trap, allowing a detailed study of the physics of Abelian lattice gauge theories related to one-dimensional quantum electrodynamics. Relying on the rich quantum-simulation toolbox available in state-of-the-art trapped-ion experiments, we show how one can engineer an effectively gauge-invariant dynamics by imposing energetic constraints, provided by strong Ising-like interactions. Applying exact diagonalization to ground-state and time-dependent properties, we study the underlying microscopic model and discuss undesired interaction terms and other imperfections. As our analysis shows, the proposed scheme allows for the observation in realistic setups of spontaneous parity- and charge-symmetry breaking, as well as false-vacuum decay. Besides an implementation aimed at larger ion chains, we also discuss a minimal setting, consisting of only four ions in a simpler experimental setup, which enables us to probe basic physical phenomena related to the full many-body problem. The proposal opens a new route for analog quantum simulation of high-energy and condensed-matter models where gauge symmetries play a prominent role.

Electron traps in semiconducting polymers : Exponential versus Gaussian trap distribution

NARCIS (Netherlands)

Nicolai, H. T.; Mandoc, M. M.; Blom, P. W. M.

2011-01-01

The low electron currents in poly(dialkoxy-p-phenylene vinylene) (PPV) derivatives and their steep voltage dependence are generally explained by trap-limited conduction in the presence of an exponential trap distribution. Here we demonstrate that the electron transport of several PPV derivatives can

Electron traps in semiconducting polymers: exponential versus Gaussian trap distribution

NARCIS (Netherlands)

Nicolai, H.T.; Mandoc, M.M.; Blom, P.W.M.

2011-01-01

The low electron currents in poly(dialkoxy-p-phenylene vinylene) (PPV) derivatives and their steep voltage dependence are generally explained by trap-limited conduction in the presence of an exponential trap distribution. Here we demonstrate that the electron transport of several PPV derivatives can

Secretion Trap Tagging of Secreted and Membrane-Spanning Proteins Using Arabidopsis Gene Traps

Science.gov (United States)

Andrew T. Groover; Joseph R. Fontana; Juana M. Arroyo; Cristina Yordan; W. Richard McCombie; Robert A. Martienssen

2003-01-01

Secreted and membrane-spanning proteins play fundamental roles in plant development but pose challenges for genetic identification and characterization. We describe a "secretion trap" screen for gene trap insertions in genes encoding proteins routed through the secretory pathway. The gene trap transposon encodes a ß-glucuronidase reporter enzyme...

Trapping for invasive crayfish: comparisons of efficacy and selectivity of baited traps versus novel artificial refuge traps

Directory of Open Access Journals (Sweden)

Green Nicky

2018-01-01

Full Text Available Non-native crayfish can dominate the invertebrate biomass of invaded freshwaters, with their high ecological impacts resulting in their populations being controlled by numerous methods, especially trapping. Although baited funnel traps (BTs are commonly used, they tend to be selective in mainly catching large-bodied males. Here, the efficacy and selectivity of BTs were tested against an alternative trapping method based on artificial refuges (ARTs that comprised of a metal base with several tubes (refuges attached. The target species was signal crayfish Pacifastacus leniusculus in an upland river in southwest England. Trapping was completed in April to October over two consecutive years. In total, 5897 crayfish were captured, with 87% captured in ARTs. Comparison of the catch per unit effort (CPUE between the trapping methods in the same 24 hour periods revealed significantly higher CPUE in ARTs than of BTs. ARTs fished for 6 consecutive days had higher catches than both methods over 24 hours. Whilst catches in BTs were significantly dominated by males (1.49M:1F, the sex ratio of catches in ARTs was 0.99M:1F. The mean carapace length of crayfish was also significantly larger in BTs (43.2 ± 0.6 mm than in ARTs (33.6 ± 0.2 mm. Thus, ARTs had higher CPUE over 24 hour and 6 day periods versus BTs and also captured a greater proportion of smaller and female individuals. These results indicate that when trapping methods are deployed for managing invasions, the use of ARTs removes substantial numbers of crayfish of both sexes and of varying body sizes.

Segmented trapped vortex cavity

Science.gov (United States)

Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

2010-01-01

An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

Electromagnetic trapping of neutral atoms

International Nuclear Information System (INIS)

Metcalf, H.J.

1986-01-01

Cooling and trapping of neutral atoms is a new branch of applied physics that has potential for application in many areas. The authors present an introduction to laser cooling and magnetic trapping. Some basic ideas and fundamental limitations are discussed, and the first successful experiments are reviewed. Trapping a neutral object depends on the interaction between an inhomogeneous electromagnetic field and a multiple moment that results in the exchange of kinetic for potential energy. In neutral atom traps, the potential energy must be stored as internal atomic energy, resulting in two immediate and extremely important consequences. First, the atomic energy levels will necessarily shift as the atoms move in the trap, and, second, practical traps for ground state neutral atoms atr necessarily very shallow compared to thermal energy. This small depth also dictates stringent vacuum requirements because a trapped atom cannot survive a single collision with a thermal energy background gas molecule. Neutral trapping, therefore, depends on substantial cooling of a thermal atomic sample and is inextricably connected with the cooling process

Lung radiology and pulmonary function of children chronically exposed to air pollution.

Science.gov (United States)

Calderón-Garcidueñas, Lilian; Mora-Tiscareño, Antonieta; Fordham, Lynn A; Chung, Charles J; Valencia-Salazar, Gildardo; Flores-Gómez, Silvia; Solt, Anna C; Gomez-del Campo, Alberto; Jardón-Torres, Ricardo; Henríquez-Roldán, Carlos; Hazucha, Milan J; Reed, William

2006-09-01

We analyzed the chest radiographs (CXRs) of 249 clinically healthy children, 230 from southwest Mexico City and 19 from Tlaxcala. In contrast to children from Tlaxcala, children from southwest Mexico City were chronically exposed to ozone levels exceeding the U.S. National Ambient Air Quality Standards for an average of 4.7 hr/day and to concentrations of particulate matter (PM) with aerodynamic diameters prominent central airways in 4 of 25, air trapping in 8 of 21, and pulmonary nodules in 2 of 21. Only 7.8% of Mexico City children had abnormal lung function tests based on predicted values. These findings are consistent with bronchiolar, peribronchiolar, and/or alveolar duct inflammation, possibly caused by ozone, PM, and lipopolysaccharide exposure. The epidemiologic implications of these findings are important for children residing in polluted environments, because bronchiolar disease could lead to chronic pulmonary disease later in life.

Motions in Prominence Barbs as observed by Hinode/SOT and IRIS

Science.gov (United States)

Kucera, Therese A.; Ofman, Leon; Tarbell, Theodore D.

2016-05-01

We discuss observations of prominence barb dynamics as observed by Hinode/SOT and IRIS. Prominence barbs extend outwards to the side of the main prominence spine and downwards towards the chromosphere. Their properties, including the structure of their magnetic field and the nature of the motions observed in them are a subject of current debate. We use a combination of high cadence, high resolution imaging, H-alpha Doppler, and Mg II line profile data to analyze and understand waves and flows in barbs and discuss their ramifications in terms of a model of the barb magnetic field as collection of dipped field lines.

CRITICAL HEIGHT FOR THE DESTABILIZATION OF SOLAR PROMINENCES: STATISTICAL RESULTS FROM STEREO OBSERVATIONS

Energy Technology Data Exchange (ETDEWEB)

Liu Kai; Wang Yuming; Wang Shui; Shen Chenglong, E-mail: ymwang@ustc.edu.cn [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2012-01-10

At which height is a prominence inclined to be unstable, or where is the most probable critical height for the prominence destabilization? This question was statistically studied based on 362 solar limb prominences well recognized by Solar Limb Prominence Catcher and Tracker from 2007 April to the end of 2009. We found that there are about 71% disrupted prominences (DPs), among which about 42% of them did not erupt successfully and about 89% of them experienced a sudden destabilization process. After a comprehensive analysis of the DPs, we discovered the following: (1) Most DPs become unstable at a height of 0.06-0.14 R{sub Sun} from the solar surface, and there are two most probable critical heights at which a prominence is very likely to become unstable, the first one is 0.13 R{sub Sun} and the second one is 0.19 R{sub Sun }. (2) An upper limit for the erupting velocity of eruptive prominences (EPs) exists, which decreases following a power law with increasing height and mass; accordingly, the kinetic energy of EPs has an upper limit too, which decreases as the critical height increases. (3) Stable prominences are generally longer and heavier than DPs, and not higher than 0.4 R{sub Sun }. (4) About 62% of the EPs were associated with coronal mass ejections (CMEs); but there is no difference in apparent properties between EPs associated with CMEs and those that are not.

CRITICAL HEIGHT FOR THE DESTABILIZATION OF SOLAR PROMINENCES: STATISTICAL RESULTS FROM STEREO OBSERVATIONS

International Nuclear Information System (INIS)

Liu Kai; Wang Yuming; Wang Shui; Shen Chenglong

2012-01-01

At which height is a prominence inclined to be unstable, or where is the most probable critical height for the prominence destabilization? This question was statistically studied based on 362 solar limb prominences well recognized by Solar Limb Prominence Catcher and Tracker from 2007 April to the end of 2009. We found that there are about 71% disrupted prominences (DPs), among which about 42% of them did not erupt successfully and about 89% of them experienced a sudden destabilization process. After a comprehensive analysis of the DPs, we discovered the following: (1) Most DPs become unstable at a height of 0.06-0.14 R ☉ from the solar surface, and there are two most probable critical heights at which a prominence is very likely to become unstable, the first one is 0.13 R ☉ and the second one is 0.19 R ☉ . (2) An upper limit for the erupting velocity of eruptive prominences (EPs) exists, which decreases following a power law with increasing height and mass; accordingly, the kinetic energy of EPs has an upper limit too, which decreases as the critical height increases. (3) Stable prominences are generally longer and heavier than DPs, and not higher than 0.4 R ☉ . (4) About 62% of the EPs were associated with coronal mass ejections (CMEs); but there is no difference in apparent properties between EPs associated with CMEs and those that are not.

A directional passive air sampler for monitoring polycyclic aromatic hydrocarbons (PAHs) in air mass

International Nuclear Information System (INIS)

Tao, S.; Liu, Y.N.; Lang, C.; Wang, W.T.; Yuan, H.S.; Zhang, D.Y.; Qiu, W.X.; Liu, J.M.; Liu, Z.G.; Liu, S.Z.; Yi, R.; Ji, M.; Liu, X.X.

2008-01-01

A passive air sampler was developed for collecting polycyclic aromatic hydrocarbons (PAHs) in air mass from various directions. The airflow velocity within the sampler was assessed for its responses to ambient wind speed and direction. The sampler was examined for trapped particles, evaluated quantitatively for influence of airflow velocity and temperature on PAH uptake, examined for PAH uptake kinetics, calibrated against active sampling, and finally tested in the field. The airflow volume passing the sampler was linearly proportional to ambient wind speed and sensitive to wind direction. The uptake rate for an individual PAH was a function of airflow velocity, temperature and the octanol-air partitioning coefficient of the PAH. For all PAHs with more than two rings, the passive sampler operated in a linear uptake phase for three weeks. Different PAH concentrations were obtained in air masses from different directions in the field test. - A novel directional passive air sampler was developed and tested for monitoring PAHs in air masses from different directions

STRUCTURE OF PROMINENCE LEGS: PLASMA AND MAGNETIC FIELD

Energy Technology Data Exchange (ETDEWEB)

Levens, P. J.; Labrosse, N. [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom); Schmieder, B. [Observatoire de Paris, Meudon, F-92195 (France); Ariste, A. López, E-mail: p.levens.1@research.gla.ac.uk [Institut de Recherche en Astrophysique et Planétologie, Toulouse (France)

2016-02-10

We investigate the properties of a “solar tornado” observed on 2014 July 15, and aim to link the behavior of the plasma to the internal magnetic field structure of the associated prominence. We made multi-wavelength observations with high spatial resolution and high cadence using SDO/AIA, the Interface Region Imaging Spectrograph (IRIS) spectrograph, and the Hinode/Solar Optical Telescope (SOT) instrument. Along with spectropolarimetry provided by the Télescope Héliographique pour l’Etude du Magnétisme et des Instabilités Solaires telescope we have coverage of both optically thick emission lines and magnetic field information. AIA reveals that the two legs of the prominence are strongly absorbing structures which look like they are rotating, or oscillating in the plane of the sky. The two prominence legs, which are both very bright in Ca ii (SOT), are not visible in the IRIS Mg ii slit-jaw images. This is explained by the large optical thickness of the structures in Mg ii, which leads to reversed profiles, and hence to lower integrated intensities at these locations than in the surroundings. Using lines formed at temperatures lower than 1 MK, we measure relatively low Doppler shifts on the order of ±10 km s{sup −1} in the tornado-like structure. Between the two legs we see loops in Mg ii, with material flowing from one leg to the other, as well as counterstreaming. It is difficult to interpret our data as showing two rotating, vertical structures that are unrelated to the loops. This kind of “tornado” scenario does not fit with our observations. The magnetic field in the two legs of the prominence is found to be preferentially horizontal.

The β-decay Paul trap: A radiofrequency-quadrupole ion trap for precision β-decay studies

International Nuclear Information System (INIS)

Scielzo, N.D.; Li, G.; Sternberg, M.G.; Savard, G.; Bertone, P.F.; Buchinger, F.; Caldwell, S.; Clark, J.A.; Crawford, J.; Deibel, C.M.; Fallis, J.; Greene, J.P.

2012-01-01

The β-decay Paul trap is a linear radiofrequency-quadrupole ion trap that has been developed for precision β-decay studies. The design of the trap electrodes allows a variety of radiation detectors to surround the cloud of trapped ions. The momentum of the low-energy recoiling daughter nuclei following β decay is negligibly perturbed by scattering and is available for study. This advantageous property of traps allows the kinematics of particles that are difficult or even impossible to directly detect to be precisely reconstructed using conservation of energy and momentum. An ion-trap system offers several advantages over atom traps, such as higher trapping efficiencies and element-independent capabilities. The first precision experiment using this system is a measurement of β-decay angular correlations in the decay of 8 Li performed by inferring the momentum of the neutrino from the kinematic shifts imparted to the breakup α particles. Many other β-decay studies that would benefit from a determination of the nuclear recoil can be performed with this system.

The {beta}-decay Paul trap: A radiofrequency-quadrupole ion trap for precision {beta}-decay studies

Energy Technology Data Exchange (ETDEWEB)

Scielzo, N.D., E-mail: scielzo1@llnl.gov [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Li, G. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Sternberg, M.G.; Savard, G. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Bertone, P.F. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Buchinger, F. [Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Caldwell, S. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Clark, J.A. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Crawford, J. [Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Deibel, C.M. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824 (United States); Fallis, J. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2 (Canada); Greene, J.P. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); and others

2012-07-21

The {beta}-decay Paul trap is a linear radiofrequency-quadrupole ion trap that has been developed for precision {beta}-decay studies. The design of the trap electrodes allows a variety of radiation detectors to surround the cloud of trapped ions. The momentum of the low-energy recoiling daughter nuclei following {beta} decay is negligibly perturbed by scattering and is available for study. This advantageous property of traps allows the kinematics of particles that are difficult or even impossible to directly detect to be precisely reconstructed using conservation of energy and momentum. An ion-trap system offers several advantages over atom traps, such as higher trapping efficiencies and element-independent capabilities. The first precision experiment using this system is a measurement of {beta}-decay angular correlations in the decay of {sup 8}Li performed by inferring the momentum of the neutrino from the kinematic shifts imparted to the breakup {alpha} particles. Many other {beta}-decay studies that would benefit from a determination of the nuclear recoil can be performed with this system.

Non-LTE hydrogen-line formation in moving prominences

Science.gov (United States)

Heinzel, P.; Rompolt, B.

1986-01-01

The behavior of hydrogen-line brightness variations, depending on the prominence-velocity changes were investigated. By solving the NON-Local thermodynamic equilibrium (LTE) problem for hydrogen researchers determine quantitatively the effect of Doppler brightening and/or Doppler dimming (DBE, DDE) in the lines of Lyman and Balmer series. It is demonstrated that in low-density prominence plasmas, DBE in H alpha and H beta lines can reach a factor of three for velocities around 160 km/sec, while the L alpha line exhibits typical DDE. L beta brightness variations follow from a combined DBE in the H alpha and DDE in L alpha and L beta itself, providing that all relevant multilevel interlocking processes are taken into account.

Possibilities of long duration generation of vapour of iodine 131 in the air for its trapping in French activated carbons; Possibilites de generation de longue duree dans l'air de vapeur d'iode 131 en vue de son piegeage par les charbons actifs francais

Energy Technology Data Exchange (ETDEWEB)

Billard, F.; Chevalier, G.; Pradel, J.

1962-12-17

As previous studies performed on activated carbon showed that it was necessary to possess a long duration iodine generator to determine the scope of application of some advanced theories concerning the trap mechanism of different forms of radio-iodines, the authors present a generator which uses the high temperature oxidation of sodium iodide by an air stream or an oxygen stream. A version of this apparatus using a 5 Curie source is planned to check the operation of a trap of 100.000 m{sup 3}/h with a purification coefficient of 10{sup 4}, and aimed at being mounted on the venting circuit of a nuclear reactor enclosure [French] Les etudes que nous avons effectuees sur les charbons actifs nous ont montre qu'il etait necessaire de posseder un generateur d'iode de longue duree pour preciser le domaine d'application de certaines theories avancees concernant le mecanisme de piegeage des differentes formes de radioiodes. Un generateur utilisant l'oxydation de l'iodure de sodium a chaud par un courant d'air ou d'oxygene est decrit. Une version de cet appareil utilisant une source de 5 curies est prevue pour verifier le bon fonctionnement d'un piege de 100.000 m{sup 3}/h ayant un coefficient d'epuration de 10{sup 4} est destine a etre place sur le circuit de ventilation de l'enceinte d'un reacteur nucleaire. (auteurs)

Ion trap architectures and new directions

Science.gov (United States)

Siverns, James D.; Quraishi, Qudsia

2017-12-01

Trapped ion technology has seen advances in performance, robustness and versatility over the last decade. With increasing numbers of trapped ion groups worldwide, a myriad of trap architectures are currently in use. Applications of trapped ions include: quantum simulation, computing and networking, time standards and fundamental studies in quantum dynamics. Design of such traps is driven by these various research aims, but some universally desirable properties have lead to the development of ion trap foundries. Additionally, the excellent control achievable with trapped ions and the ability to do photonic readout has allowed progress on quantum networking using entanglement between remotely situated ion-based nodes. Here, we present a selection of trap architectures currently in use by the community and present their most salient characteristics, identifying features particularly suited for quantum networking. We also discuss our own in-house research efforts aimed at long-distance trapped ion networking.

Homopolar dc motor and trapped flux brushless dc motor using high temperature superconductor materials

Science.gov (United States)

Crapo, Alan D.; Lloyd, Jerry D.

1991-03-01

Two motors have been designed and built for use with high-temperature superconductor (HTSC) materials. They are a homopolar dc motor that uses HTSC field windings and a brushless dc motor that uses bulk HTSC materials to trap flux in steel rotor poles. The HTSC field windings of the homopolar dc motor are designed to operate at 1000 A/sq cm in a 0.010-T field. In order to maximize torque in the homopolar dc motor, an iron magnetic circuit with small air gaps gives maximum flux for minimum Ampere turns in the field. A copper field winding version of the homopolar dc motor has been tested while waiting for 575 A turn HTSC coils. The trapped flux brushless dc motor has been built and is ready to test melt textured bulk HTSC rings that are currently being prepared. The stator of the trapped flux motor will impress a magnetic field in the steel rotor poles with warm HTSC bulk rings. The rings are then cooled to 77 K to trap the flux in the rotor. The motor can then operate as a brushless dc motor.

Development of Carbotrap B-packed needle trap device for determination of volatile organic compounds in air.

Science.gov (United States)

Poormohammadi, Ali; Bahrami, Abdulrahman; Farhadian, Maryam; Ghorbani Shahna, Farshid; Ghiasvand, Alireza

2017-12-08

Carbotrap B as a highly pure surface sorbent with excellent adsorption/desorption properties was packed into a stainless steel needle to develop a new needle trap device (NTD). The performance of the prepared NTD was investigated for sampling, pre-concentration and injection of benzene, toluene, ethyl benzene, o-xylene, and p-xylene (BTEX) into the column of gas chromatography-mass spectrometry (GC-MS) device. Response surface methodology (RSM) with central composite design (CCD) was also employed in two separate consecutive steps to optimize the sampling and device parameters. First, the sampling parameters such as sampling temperature and relative humidity were optimized. Afterwards, the RSM was used for optimizing the desorption parameters including desorption temperature and time. The results indicated that the peak area responses of the analytes of interest decreased with increasing sampling temperature and relative humidity. The optimum values of desorption temperature were in the range 265-273°C, and desorption time were in the range 3.4-3.8min. The limits of detection (LODs) and limits of quantitation (LOQs) of the studied analytes were found over the range of 0.03-0.04ng/mL, and 0.1-0.13ng/mL, respectively. These results demonstrated that the NTD packed with Carbotrap B offers a high sensitive procedure for sampling and analysis of BTEX in concentration range of 0.03-25ng/mL in air. Copyright © 2017 Elsevier B.V. All rights reserved.

A magnetic particle micro-trap for large trapping surfaces

KAUST Repository

Gooneratne, Chinthaka P.

2012-01-08

Manipulation of micron-size magnetic particles of the superparamagnetic type contributes significantly in many applications like controlling the antibody/antigen binding process in immunoassays. Specifically, more target biomolecules can be attached/tagged and analyzed since the three dimensional structure of the magnetic particles increases the surface to volume ratio. Additionally, such biomolecular-tagged magnetic particles can be easily manipulated by an external magnetic field due to their superparamagnetic behavior. Therefore, magnetic particle- based immunoassays are extensively applied in micro-flow cytometry. The design of a square-loop micro-trap as a magnetic particle manipulator as well as numerical and experimental analysis is presented. Experimental results showed that the micro-trap could successfully trap and concentrate magnetic particles from a large to a small area with a high spatial range.

A magnetic particle micro-trap for large trapping surfaces

KAUST Repository

Gooneratne, Chinthaka P.; Liang, Cai; Giouroudi, Ioanna; Kosel, Jü rgen

2012-01-01

Manipulation of micron-size magnetic particles of the superparamagnetic type contributes significantly in many applications like controlling the antibody/antigen binding process in immunoassays. Specifically, more target biomolecules can be attached/tagged and analyzed since the three dimensional structure of the magnetic particles increases the surface to volume ratio. Additionally, such biomolecular-tagged magnetic particles can be easily manipulated by an external magnetic field due to their superparamagnetic behavior. Therefore, magnetic particle- based immunoassays are extensively applied in micro-flow cytometry. The design of a square-loop micro-trap as a magnetic particle manipulator as well as numerical and experimental analysis is presented. Experimental results showed that the micro-trap could successfully trap and concentrate magnetic particles from a large to a small area with a high spatial range.

Quantitative analysis of charge trapping and classification of sub-gap states in MoS2 TFT by pulse I-V method

Science.gov (United States)

Park, Junghak; Hur, Ji-Hyun; Jeon, Sanghun

2018-04-01

The threshold voltage instabilities and huge hysteresis of MoS2 thin film transistors (TFTs) have raised concerns about their practical applicability in next-generation switching devices. These behaviors are associated with charge trapping, which stems from tunneling to the adjacent trap site, interfacial redox reaction and interface and/or bulk trap states. In this report, we present quantitative analysis on the electron charge trapping mechanism of MoS2 TFT by fast pulse I-V method and the space charge limited current (SCLC) measurement. By adopting the fast pulse I-V method, we were able to obtain effective mobility. In addition, the origin of the trap states was identified by disassembling the sub-gap states into interface trap and bulk trap states by simple extraction analysis. These measurement methods and analyses enable not only quantitative extraction of various traps but also an understanding of the charge transport mechanism in MoS2 TFTs. The fast I-V data and SCLC data obtained under various measurement temperatures and ambient show that electron transport to neighboring trap sites by tunneling is the main charge trapping mechanism in thin-MoS2 TFTs. This implies that interfacial traps account for most of the total sub-gap states while the bulk trap contribution is negligible, at approximately 0.40% and 0.26% in air and vacuum ambient, respectively. Thus, control of the interface trap states is crucial to further improve the performance of devices with thin channels.

ATRAP - Progress Towards Trapped Antihydrogen

International Nuclear Information System (INIS)

Grzonka, D.; Goldenbaum, F.; Oelert, W.; Sefzick, T.; Zhang, Z.; Comeau, D.; Hessels, E.A.; Storry, C.H.; Gabrielse, G.; Larochelle, P.; Lesage, D.; Levitt, B.; Speck, A.; Haensch, T.W.; Pittner, H.; Walz, J.

2005-01-01

The ATRAP experiment at the CERN antiproton decelerator AD aims for a test of the CPT invariance by a high precision comparison of the 1s-2s transition in the hydrogen and the antihydrogen atom.Antihydrogen production is routinely operated at ATRAP and detailed studies have been performed in order to optimize the production efficiency of useful antihydrogen.For high precision measurements of atomic transitions cold antihydrogen in the ground state is required which must be trapped due to the low number of available antihydrogen atoms compared to the cold hydrogen beam used for hydrogen spectroscopy. To ensure a reasonable antihydrogen trapping efficiency a magnetic trap has to be superposed the nested Penning trap. First trapping tests of charged particles within a combined magnetic/Penning trap have started at ATRAP

ATRAP Progress Towards Trapped Antihydrogen

CERN Document Server

Grzonka, D; Gabrielse, G; Goldenbaum, F; Hänsch, T W; Hessels, E A; Larochelle, P; Le Sage, D; Levitt, B; Oelert, W; Pittner, H; Sefzick, T; Speck, A; Storry, C H; Walz, J; Zhang, Z

2005-01-01

The ATRAP experiment at the CERN antiproton decelerator AD aims for a test of the CPT invariance by a high precision comparison of the 1s‐2s transition in the hydrogen and the antihydrogen atom. Antihydrogen production is routinely operated at ATRAP and detailed studies have been performed in order to optimize the production efficiency of useful antihydrogen. For high precision measurements of atomic transitions cold antihydrogen in the ground state is required which must be trapped due to the low number of available antihydrogen atoms compared to the cold hydrogen beam used for hydrogen spectroscopy. To ensure a reasonable antihydrogen trapping efficiency a magnetic trap has to be superposed the nested Penning trap. First trapping tests of charged particles within a combined magnetic/Penning trap have started at ATRAP.

Status of THe-trap

Energy Technology Data Exchange (ETDEWEB)

Ketter, Jochen; Eronen, Tommi; Hoecker, Martin; Streubel, Sebastian; Blaum, Klaus [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Van Dyck, Robert S. Jr. [Department of Physics, University of Washington, Seattle, WA (United States)

2012-07-01

Originally developed at the University of Washington and relocated to the Max-Planck-Institut fuer Kernphysik in 2008, the Penning-trap spectrometer THe-Trap is specially tailored for a {sup 3}H/{sup 3}He mass-ratio measurement, from which the Q-value of the beta-decay of {sup 3}H to {sup 3}He can be derived. Improving the current best value by at least an order of magnitude will provide an important independent test parameter for the determination of the electron-antineutrino's mass by the Karlsruhe Tritium Neutrino Experiment (KATRIN). However, Penning-trap mass spectrometry has to be pushed to its limits in a dedicated experiment for a sufficiently accurate mass-ratio measurement with a relative uncertainty of 10{sup -11}. Unlike the closed-envelope, single-trap predecessor, the new spectrometer features an external ion source, owing to the radioactive nature of tritium, and two traps in order to speed up the measurement cycle. While the double-trap technique holds great promise, it also calls for more intricate procedures, such as ion transfer. Details about the recent progress of the experiment are given.

Servo control of an optical trap.

Science.gov (United States)

Wulff, Kurt D; Cole, Daniel G; Clark, Robert L

2007-08-01

A versatile optical trap has been constructed to control the position of trapped objects and ultimately to apply specified forces using feedback control. While the design, development, and use of optical traps has been extensive and feedback control has played a critical role in pushing the state of the art, few comprehensive examinations of feedback control of optical traps have been undertaken. Furthermore, as the requirements are pushed to ever smaller distances and forces, the performance of optical traps reaches limits. It is well understood that feedback control can result in both positive and negative effects in controlled systems. We give an analysis of the trapping limits as well as introducing an optical trap with a feedback control scheme that dramatically improves an optical trap's sensitivity at low frequencies.

Algae commensal community in Genlisea traps

Directory of Open Access Journals (Sweden)

Konrad Wołowski

2011-01-01

Full Text Available The community of algae occurring in Genlisea traps and on the external traps surface in laboratory conditions were studied. A total of 29 taxa were found inside the traps, with abundant diatoms, green algae (Chlamydophyceae and four morphotypes of chrysophytes stomatocysts. One morphotype is described as new for science. There are two ways of algae getting into Genlisea traps. The majority of those recorded inside the traps, are mobile; swimming freely by flagella or moving exuding mucilage like diatoms being ablate to colonize the traps themselves. Another possibility is transport of algae by invertebrates such as mites and crustaceans. In any case algae in the Genlisea traps come from the surrounding environment. Two dominant groups of algae (Chladymonas div. and diatoms in the trap environment, show ability to hydrolyze phosphomonoseters. We suggest that algae in carnivorous plant traps can compete with plant (host for organic phosphate (phosphomonoseters. From the spectrum and ecological requirements of algal species found in the traps, environment inside the traps seems to be acidic. However, further studies are needed to test the relations between algae and carnivorous plants both in laboratory conditions and in the natural environment. All the reported taxa are described briefly and documented with 74 LM and SEM micrographs.

Full-chain health impact assessment of traffic-related air pollution and childhood asthma.

Science.gov (United States)

Khreis, Haneen; de Hoogh, Kees; Nieuwenhuijsen, Mark J

2018-05-01

Asthma is the most common chronic disease in children. Traffic-related air pollution (TRAP) may be an important exposure contributing to its development. In the UK, Bradford is a deprived city suffering from childhood asthma rates higher than national and regional averages and TRAP is of particular concern to the local communities. We estimated the burden of childhood asthma attributable to air pollution and specifically TRAP in Bradford. Air pollution exposures were estimated using a newly developed full-chain exposure assessment model and an existing land-use regression model (LUR). We estimated childhood population exposure to NO x and, by conversion, NO 2 at the smallest census area level using a newly developed full-chain model knitting together distinct traffic (SATURN), vehicle emission (COPERT) and atmospheric dispersion (ADMS-Urban) models. We compared these estimates with measurements and estimates from ESCAPE's LUR model. Using the UK incidence rate for childhood asthma, meta-analytical exposure-response functions, and estimates from the two exposure models, we estimated annual number of asthma cases attributable to NO 2 and NO x in Bradford, and annual number of asthma cases specifically attributable to traffic. The annual average census tract levels of NO 2 and NO x estimated using the full-chain model were 15.41 and 25.68 μg/m 3 , respectively. On average, 2.75 μg/m 3 NO 2 and 4.59 μg/m 3 NO x were specifically contributed by traffic, without minor roads and cold starts. The annual average census tract levels of NO 2 and NO x estimated using the LUR model were 21.93 and 35.60 μg/m 3 , respectively. The results indicated that up to 687 (or 38% of all) annual childhood asthma cases in Bradford may be attributable to air pollution. Up to 109 cases (6%) and 219 cases (12%) may be specifically attributable to TRAP, with and without minor roads and cold starts, respectively. This is the first study undertaking full-chain health impact assessment

Microfabricated linear Paul-Straubel ion trap

Science.gov (United States)

Mangan, Michael A [Albuquerque, NM; Blain, Matthew G [Albuquerque, NM; Tigges, Chris P [Albuquerque, NM; Linker, Kevin L [Albuquerque, NM

2011-04-19

An array of microfabricated linear Paul-Straubel ion traps can be used for mass spectrometric applications. Each ion trap comprises two parallel inner RF electrodes and two parallel outer DC control electrodes symmetric about a central trap axis and suspended over an opening in a substrate. Neighboring ion traps in the array can share a common outer DC control electrode. The ions confined transversely by an RF quadrupole electric field potential well on the ion trap axis. The array can trap a wide array of ions.

PATTERNS OF FLOWS IN AN INTERMEDIATE PROMINENCE OBSERVED BY HINODE

International Nuclear Information System (INIS)

Ahn, Kwangsu; Chae, Jongchul; Cao Wenda; Goode, Philip R.

2010-01-01

The investigation of plasma flows in filaments/prominences gives us clues to understanding their magnetic structures. We studied the patterns of flows in an intermediate prominence observed by Hinode/SOT. By examining a time series of Hα images and Ca II H images, we have found horizontal flows in the spine and vertical flows in the barb. Both of these flows have a characteristic speed of 10-20 km s -1 . The horizontal flows displayed counterstreaming. Our detailed investigation revealed that most of the moving fragments in fact reversed direction at the end point of the spine near a footpoint close to the associated active region. These returning flows may be one possible explanation of the well-known counterstreaming flows in prominences. In contrast, we have found vertical flows-downward and upward-in the barb. Most of the horizontal flows in the spine seem to switch into vertical flows when they approach the barb, and vice versa. We propose that the net force resulting from a small deviation from magnetohydrostatic equilibrium, where magnetic fields are predominantly horizontal, may drive these patterns of flow. In the prominence studied here, the supposed magnetohydrostatic configuration is characterized by magnetic field lines sagging with angles of 13 0 and 39 0 in the spine and the barb, respectively.

Extreme-ultraviolet limb spectra of a prominence observed from SKYLAB

International Nuclear Information System (INIS)

Mariska, J.T.; Doschek, G.A.; Feldman, U.

1979-01-01

Line profiles of extreme ultraviolet emission lines observed in a solar prominence at positions above the white-light limb with the NRL slit spectrograph on Skylab are discussed. Absolute line intensities and full widths at half-maximum are presented for lines formed over the temperature range approx.1 x 10 4 to 2.2 x 10 5 K. The volume emission measures calculated using resonance line intensities are greater than quiet-Sun emission measures at the same height above the limb and indicate a somewhat different distribution of material with temperature in the prominence compared to the quiet-Sun emission measure at +8''. Electron densities in the prominence determined using the calculated emission measures and the intensities of density-sensitive intersystem lines are between the quiet-Sun electron density and half the quiet-Sun electron density. Random mass-motion velocities calculated from the measured full widths at half-maximum show a range of velocities. For T/sub e/> or approx. =4 x 10 4 K, the nonthermal velocity decreases with increasing height in the prominence. For T/sub e/ 4 K, the calculated mass motions are near zero. From the He II 1640 A line profile we derive an average temperature of 27,000 K for the region in which He II is emitted

Two-baffle trap for macroparticles

International Nuclear Information System (INIS)

Aksyonov, D.S.

2014-01-01

In this work, properties of two-baffle macroparticle traps were investigated. These properties are needed for designing and optimization of vacuum arc plasma filters. The dependencies between trap geometry parameters and its ability to absorb macroparticles were found. Calculations made allow one to predict the behaviour of filtering abilities of separators containing such traps in their design. Recommendations regarding the use of two-baffle traps in filters of different builds are given

Ion Trap Quantum Computing

Science.gov (United States)

2011-12-01

variations of ion traps, including (1) the cylindrically symmetric 3D ring trap; (2) the linear trap with a combination of cavity QED; (#) the symmetric...concepts of quantum information. The major demonstration has been the test of a Bell inequality as demonstrated by Rowe et al. [50] and a decoherence...famous physics experiment [62]. Wolfgang Paul demonstrated a similar apparatus during his Nobel Prize speech [63]. This device is hyperbolic- parabolic

EVIDENCE FOR ROTATIONAL MOTIONS IN THE FEET OF A QUIESCENT SOLAR PROMINENCE

International Nuclear Information System (INIS)

Orozco Suárez, D.; Asensio Ramos, A.; Trujillo Bueno, J.

2012-01-01

We present observational evidence of apparent plasma rotational motions in the feet of a solar prominence. Our study is based on spectroscopic observations taken in the He I 1083.0 nm multiplet with the Tenerife Infrared Polarimeter attached to the German Vacuum Tower Telescope. We recorded a time sequence of spectra with 34 s cadence placing the slit of the spectrograph almost parallel to the solar limb and crossing two feet of an intermediate size, quiescent hedgerow prominence. The data show opposite Doppler shifts, ±6 km s –1 , at the edges of the prominence feet. We argue that these shifts may be interpreted as prominence plasma rotating counterclockwise around the vertical axis to the solar surface as viewed from above. The evolution of the prominence seen in EUV images taken with the Solar Dynamics Observatory provided us with clues to interpret the results as swirling motions. Moreover, time-distance images taken far from the central wavelength show plasma structures moving parallel to the solar limb with velocities of about 10-15 km s –1 . Finally, the shapes of the observed intensity profiles suggest the presence of, at least, two components at some locations at the edges of the prominence feet. One of them is typically Doppler shifted (up to ∼20 km s –1 ) with respect to the other, thus suggesting the existence of supersonic counter-streaming flows along the line of sight.

Versatile electrostatic trap

NARCIS (Netherlands)

van Veldhoven, J.; Bethlem, H.L.; Schnell, M.; Meijer, G.

2006-01-01

A four electrode electrostatic trap geometry is demonstrated that can be used to combine a dipole, quadrupole, and hexapole field. A cold packet of ND315 molecules is confined in both a purely quadrupolar and hexapolar trapping field and additionally, a dipole field is added to a hexapole field to

On Lyman-line asymmetries in quiescent prominences

Czech Academy of Sciences Publication Activity Database

Gunár, Stanislav; Heinzel, Petr; Anzer, U.; Schmieder, B.

2008-01-01

Roč. 490, č. 1 (2008), s. 307-313 ISSN 0004-6361 Grant - others:EU(XE) ESA-PECS project No. 98030 Institutional research plan: CEZ:AV0Z10030501 Keywords : Sun prominences * radiative transfer * line profiles Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.153, year: 2008

Topic Prominence in Chinese EFL Learners' Interlanguage

Science.gov (United States)

Li, Shaopeng; Yang, Lianrui

2014-01-01

The present study aims to investigate the general characteristics of topicprominent typological interlanguage development of Chinese learners of English in terms of acquiring subject-prominent English structures from a discourse perspective. Topic structures mainly appear in Chinese discourse in the form of topic chains (Wang, 2002; 2004). The…

A circularly polarized optical dipole trap and other developments in laser trapping of atoms

Science.gov (United States)

Corwin, Kristan Lee

Several innovations in laser trapping and cooling of alkali atoms are described. These topics share a common motivation to develop techniques for efficiently manipulating cold atoms. Such advances facilitate sensitive precision measurements such as parity non- conservation and 8-decay asymmetry in large trapped samples, even when only small quantities of the desired species are available. First, a cold, bright beam of Rb atoms is extracted from a magneto-optical trap (MOT) using a very simple technique. This beam has a flux of 5 × 109 atoms/s and a velocity of 14 m/s, and up to 70% of the atoms in the MOT were transferred to the atomic beam. Next, a highly efficient MOT for radioactive atoms is described, in which more than 50% of 221Fr atoms contained in a vapor cell are loaded into a MOT. Measurements were also made of the 221Fr 7 2P1/2 and 7 2P3/2 energies and hyperfine constants. To perform these experiments, two schemes for stabilizing the frequency of the light from a diode laser were developed and are described in detail. Finally, a new type of trap is described and a powerful cooling technique is demonstrated. The circularly polarized optical dipole trap provides large samples of highly spin-polarized atoms, suitable for many applications. Physical processes that govern the transfer of large numbers of atoms into the trap are described, and spin-polarization is measured to be 98(1)%. In addition, the trap breaks the degeneracy of the atomic spin states much like a magnetic trap does. This allows for RF and microwave cooling via both forced evaporation and a Sisyphus mechanism. Preliminary application of these techniques to the atoms in the circularly polarized dipole trap has successfully decreased the temperature by a factor of 4 while simultaneously increasing phase space density.

Efficacy of multifunnel traps for capturing emerald ash borer (Coleoptera: Buprestidae): effect of color, glue, and other trap coatings.

Science.gov (United States)

Francese, Joseph A; Fraser, Ivich; Lance, David R; Mastro, Victor C

2011-06-01

Tens of thousands of adhesive-coated purple prism traps are deployed annually in the United States to survey for the invasive emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae). A reusable, more user-friendly trap is desired by program managers, surveyors, and researchers. Field assays were conducted in southeastern Michigan to ascertain the feasibility of using nonsticky traps as survey and detection tools for emerald ash borer. Three nonsticky trap designs, including multifunnel (Lindgren), modified intercept panel, and drainpipe (all painted purple) were compared with the standard purple prism trap; no statistical differences in capture of emerald ash borer adults were detected between the multifunnel design and the prism. In subsequent color comparison assays, both green- and purple-painted multifunnel traps (and later, plastic versions of these colors) performed as well or better than the prism traps. Multifunnel traps coated with spray-on adhesive caught more beetles than untreated traps. The increased catch, however, occurred in the traps' collection cups and not on the trap surface. In a separate assay, there was no significant difference detected between glue-coated traps and Rain-X (normally a glass treatment)-coated traps, but both caught significantly more A. planipennis adults than untreated traps.

Clinico-Epidemiological Comparison of Delusion-Prominent and Hallucination-Prominent Clinical Subgroups of Paranoid Schizophrenia.

Science.gov (United States)

Kreinin, Anatoly; Krishtul, Vladimir; Kirsh, Zvi; Menuchin, Michael

2015-01-01

Though hallucinations and delusions are prominent basic impairments in schizophrenia, reports of the relationship between hallucinatory and delusional symptoms among schizophrenia patients are scant. To examine the epidemiological and clinical differences between mainly hallucinatory and mainly delusional subgroups of paranoid schizophrenia patients. One hundred schizophrenia patients, paranoid type, were recruited. In a cross-sectional study, participants were divided into Mainly Hallucinatory (H) and Mainly Delusional (D) subgroups. Demographic variables were compared and clinical characteristics were evaluated using the Scale for the Assessment of Positive Symptoms, the Scale for the Assessment of Negative Symptoms, and the Clinical Global Impression Scale. The Quality-of-Life Enjoyment and Satisfaction Questionnaire-18 was used to assess quality of life. Clinically, the H group was more heterogeneous as expressed by the broader range of scores that described the clinical picture of patients in that subgroup (in 43 of 78 variables, 55.13%) and similar ranges of scores (31 of 78 variables, 39.74%) for patients in the D group. Duration of hospitalization was significantly longer in group H than in group D (p=0.047). There was no statistically significant difference between the H and D subgroups in demographic characteristics. There are distinct epidemiological and clinical differences between the H and D subgroups, with more severe positive and negative symptoms and greater functional impairment in the H group. Paranoid schizophrenia patients with prominent hallucinations have poorer prognosis and need intensive therapeutic rehabilitation beginning with onset-of-illness. Further genetic studies and comparisons of fMRI and/or PET findings are warranted to investigate additional distinctive characteristics of these subgroups.

Particle trapping in stimulated scattering processes

International Nuclear Information System (INIS)

Karttunen, S.J.; Heikkinen, J.A.

1981-01-01

Particle trapping effects on stimulated Brillouin and Raman scattering are investigated. A time and space dependent model assumes a Maxwellian plasma which is taken to be homogeneous in the interaction region. Ion trapping has a rather weak effect on stimulated Brillouin scattering and large reflectivities are obtained even in strong trapping regime. Stimulated Raman scattering is considerably reduced by electron trapping. Typically 15-20 times larger laser intensities are required to obtain same reflectivity levels than without trapping. (author)

Trapped antihydrogen

CERN Document Server

Butler, E; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jonsell, S; Jørgensen, L V; Kemp, S L; Kurchaninov, L; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Rasmussen, C Ø; Robicheaux, F; Sarid, E; Seif el Nasr, S; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki,Y

2012-01-01

Precision spectroscopic comparison of hydrogen and antihydrogen holds the promise of a sensitive test of the Charge-Parity-Time theorem and matter-antimatter equivalence. The clearest path towards realising this goal is to hold a sample of antihydrogen in an atomic trap for interrogation by electromagnetic radiation. Achieving this poses a huge experimental challenge, as state-of-the-art magnetic-minimum atom traps have well depths of only ∼1 T (∼0.5 K for ground state antihydrogen atoms). The atoms annihilate on contact with matter and must be ‘born’ inside the magnetic trap with low kinetic energies. At the ALPHA experiment, antihydrogen atoms are produced from antiprotons and positrons stored in the form of non-neutral plasmas, where the typical electrostatic potential energy per particle is on the order of electronvolts, more than 104 times the maximum trappable kinetic energy. In November 2010, ALPHA published the observation of 38 antiproton annihilations due to antihydrogen atoms that had been ...

Spatial mismatch between sea lamprey behaviour and trap location explains low success at trapping for control

Science.gov (United States)

Rous, Andrew M.; McLean, Adrienne R.; Barber, Jessica; Bravener, Gale; Castro-Santos, Theodore; Holbrook, Christopher M.; Imre, Istvan; Pratt, Thomas C.; McLaughlin, Robert L.

2017-01-01

Crucial to the management of invasive species is understanding space use and the environmental features affecting space use. Improved understanding of space use by invasive sea lamprey (Petromyzon marinus) could help researchers discern why trap success in large rivers is lower than needed for effective control. We tested whether manipulating discharge nightly could increase trap success at a hydroelectric generating station on the St. Marys River. We quantified numbers of acoustically tagged sea lampreys migrating up to, and their space use at, the hydroelectric generating station. In 2011 and 2012, 78% and 68%, respectively, of tagged sea lampreys reached the generating station. Sea lampreys were active along the face, but more likely to occur at the bottom and away from the traps near the surface, especially when discharge was high. Our findings suggest that a low probability of encountering traps was due to spatial (vertical) mismatch between space use by sea lamprey and trap locations and that increasing discharge did not alter space use in ways that increased trap encounter. Understanding space use by invasive species can help managers assess the efficacy of trapping and ways of improving trapping success.

A prominent anchoring effect on the kinetic control of drug release from mesoporous silica nanoparticles (MSNs).

Science.gov (United States)

Tran, Vy Anh; Lee, Sang-Wha

2018-01-15

This work demonstrated kinetically controlled release of model drugs (ibuprofen, FITC) from well-tailored mesoporous silica nanoparticles (MSNs) depending on the surface charges and molecular sizes of the drugs. The molecular interactions between entrapped drugs and the pore walls of MSNs controlled the release of the drugs through the pore channels of MSNs. Also, polydopamine (PDA) layer-coated MSNs (MSNs@PDA) was quite effective to retard the release of large FITC, in contrast to a slight retardation effect on relatively small Ibuprofen. Of all things, FITC (Fluorescein isothiocyanate)-labeled APTMS (3-aminopropyltrimethoxysilane) (APTMS-FITC conjugates) grafted onto the MSNs generate a pinch-effect on the pore channel (so-called a prominent anchoring effect), which was highly effective in trapping (or blocking) drug molecules at the pore mouth of the MSNs. The anchored APTMS-FITC conjugates provided not only tortuous pathways to the diffusing molecules, but also sustained release of the ibuprofen over a long period of time (∼7days). The fast release kinetics was predicted by an exponential equation based on Fick's law, while the slow release kinetics was predicted by Higuchi model. Copyright © 2017 Elsevier Inc. All rights reserved.

Chemical characterization of individual microparticles using an ion trap: real-time chemical analysis of aerosol particles

International Nuclear Information System (INIS)

Yang, Mo; Whitten, W.B.; Reilly, P.T.A.; Gieray, R.; Ramsey, J.M.

1996-01-01

This paper describes initial experiments to perform laser ablation mass spectrometry in real time on airborne microparticles. The microparticles are sampled directly from the air by a particle inlet system into the vacuum chamber of a mass spectrometer. An incoming particle is detected as it passes through two CW laser beams and a pulsed laser is triggered to intercept the particle for laser ablation/ionization in the mass spectrometer. The initial studies were made with an existing ion trap mass spectrometer with the particle sampling occurring at the center of the trap electrodes. Performance of the inlet system, particle detection, and preliminary results are described

Quiescent Prominence Dynamics Observed with the Hinode Solar Optical Telescope. I. Turbulent Upflow Plumes

Science.gov (United States)

Berger, Thomas E.; Slater, Gregory; Hurlburt, Neal; Shine, Richard; Tarbell, Theodore; Title, Alan; Lites, Bruce W.; Okamoto, Takenori J.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Magara, Tetsuya; Suematsu, Yoshinori; Shimizu, Toshifumi

2010-06-01

Hinode/Solar Optical Telescope (SOT) observations reveal two new dynamic modes in quiescent solar prominences: large-scale (20-50 Mm) "arches" or "bubbles" that "inflate" from below into prominences, and smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are related in that they are always dark in visible-light spectral bands, they rise through the bright prominence emission with approximately constant speeds, and the small-scale upflows are sometimes observed to emanate from the top of the larger bubbles. Here we present detailed kinematic measurements of the small-scale turbulent upflows seen in several prominences in the SOT database. The dark upflows typically initiate vertically from 5 to 10 Mm wide dark cavities between the bottom of the prominence and the top of the chromospheric spicule layer. Small perturbations on the order of 1 Mm or less in size grow on the upper boundaries of cavities to generate plumes up to 4-6 Mm across at their largest widths. All plumes develop highly turbulent profiles, including occasional Kelvin-Helmholtz vortex "roll-up" of the leading edge. The flows typically rise 10-15 Mm before decelerating to equilibrium. We measure the flowfield characteristics with a manual tracing method and with the Nonlinear Affine Velocity Estimator (NAVE) "optical flow" code to derive velocity, acceleration, lifetime, and height data for several representative plumes. Maximum initial speeds are in the range of 20-30 km s-1, which is supersonic for a ~10,000 K plasma. The plumes decelerate in the final few Mm of their trajectories resulting in mean ascent speeds of 13-17 km s-1. Typical lifetimes range from 300 to 1000 s (~5-15 minutes). The area growth rate of the plumes (observed as two-dimensional objects in the plane of the sky) is initially linear and ranges from 20,000 to 30,000 km2 s-1 reaching maximum projected areas from 2 to 15 Mm2. Maximum contrast of the dark flows relative to the bright prominence plasma in SOT images

QUIESCENT PROMINENCE DYNAMICS OBSERVED WITH THE HINODE SOLAR OPTICAL TELESCOPE. I. TURBULENT UPFLOW PLUMES

International Nuclear Information System (INIS)

Berger, Thomas E.; Slater, Gregory; Hurlburt, Neal; Shine, Richard; Tarbell, Theodore; Title, Alan; Lites, Bruce W.; Okamoto, Takenori J.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Magara, Tetsuya; Suematsu, Yoshinori; Shimizu, Toshifumi

2010-01-01

Hinode/Solar Optical Telescope (SOT) observations reveal two new dynamic modes in quiescent solar prominences: large-scale (20-50 Mm) 'arches' or 'bubbles' that 'inflate' from below into prominences, and smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are related in that they are always dark in visible-light spectral bands, they rise through the bright prominence emission with approximately constant speeds, and the small-scale upflows are sometimes observed to emanate from the top of the larger bubbles. Here we present detailed kinematic measurements of the small-scale turbulent upflows seen in several prominences in the SOT database. The dark upflows typically initiate vertically from 5 to 10 Mm wide dark cavities between the bottom of the prominence and the top of the chromospheric spicule layer. Small perturbations on the order of 1 Mm or less in size grow on the upper boundaries of cavities to generate plumes up to 4-6 Mm across at their largest widths. All plumes develop highly turbulent profiles, including occasional Kelvin-Helmholtz vortex 'roll-up' of the leading edge. The flows typically rise 10-15 Mm before decelerating to equilibrium. We measure the flowfield characteristics with a manual tracing method and with the Nonlinear Affine Velocity Estimator (NAVE) 'optical flow' code to derive velocity, acceleration, lifetime, and height data for several representative plumes. Maximum initial speeds are in the range of 20-30 km s -1 , which is supersonic for a ∼10,000 K plasma. The plumes decelerate in the final few Mm of their trajectories resulting in mean ascent speeds of 13-17 km s -1 . Typical lifetimes range from 300 to 1000 s (∼5-15 minutes). The area growth rate of the plumes (observed as two-dimensional objects in the plane of the sky) is initially linear and ranges from 20,000 to 30,000 km 2 s -1 reaching maximum projected areas from 2 to 15 Mm 2 . Maximum contrast of the dark flows relative to the bright prominence plasma in

Effects of air pollution exposure on glucose metabolism in Los Angeles minority children.

Science.gov (United States)

Toledo-Corral, C M; Alderete, T L; Habre, R; Berhane, K; Lurmann, F W; Weigensberg, M J; Goran, M I; Gilliland, F D

2018-01-01

Growing evidence indicates that ambient (AAP: NO 2 , PM 2.5 and O 3 ) and traffic-related air pollutants (TRAP) contribute to metabolic disease risk in adults; however, few studies have examined these relationships in children. Metabolic profiling was performed in 429 overweight and obese African-American and Latino youth living in urban Los Angeles, California. This cross-sectional study estimated individual residential air pollution exposure and used linear regression to examine relationships between air pollution and metabolic outcomes. AAP and TRAP exposure were associated with adverse effects on glucose metabolism independent of body fat percent. PM 2.5 was associated with 25.0% higher fasting insulin (p pollution exposure was associated with a metabolic profile that is characteristic of increased risk for type 2 diabetes. These results indicate that increased prior year exposure to air pollution may adversely affect type 2 diabetes-related pathophysiology in overweight and obese minority children. © 2016 World Obesity Federation.

Radiological findings and differential diagnosis in childhood asthma

International Nuclear Information System (INIS)

Faerber, D.; Bauer, C.P.; Hahn, H.

1990-01-01

In children with asthma, routine chest X-ray typically shows bilaterally increased air volume, low diaphragms, wide diaphragmatic angles, and often a slender cardiac silhouette with a prominent pulmonic arch. Such an X-ray is not diagnostic of asthma itself, however, but rather of its complications: pneumonitis (particularly in toddlers with infectious asthma), atelectasis due to mucus obstruction, and, rarely, extra-alveolar air trapping (pneumomediastinum with or without cutaneous emphysema more often than pneumothorax). The differential diagnosis has to rule out 'pseudoasthma' due to cystic fibrosis, alveolitis, achalasia, and foreign body aspiration. (orig.) [de

St. Croix trap study

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The data set contains detailed information about the catch from 600 trap stations around St. Croix. Data fields include species caught, size data, trap location...

Trapping and Probing Antihydrogen

Energy Technology Data Exchange (ETDEWEB)

Wurtele, Jonathan [UC Berkeley and LBNL

2013-03-27

Precision spectroscopy of antihydrogen is a promising path to sensitive tests of CPT symmetry. The most direct route to achieve this goal is to create and probe antihydrogen in a magnetic minimum trap. Antihydrogen has been synthesized and trapped for 1000s at CERN by the ALPHA Collaboration. Some of the challenges associated with achieving these milestones will be discussed, including mixing cryogenic positron and antiproton plasmas to synthesize antihydrogen with kinetic energy less than the trap potential of .5K. Recent experiments in which hyperfine transitions were resonantly induced with microwaves will be presented. The opportunity for gravitational measurements in traps based on detailed studies of antihydrogen dynamics will be described. The talk will conclude with a discussion future antihydrogen research that will use a new experimental apparatus, ALPHA-I.

Continuous Arsine Detection Using a Peltier-Effect Cryogenic Trap To Selectively Trap Methylated Arsines.

Science.gov (United States)

Chen, Guoying; Lai, Bunhong; Mao, Xuefei; Chen, Tuanwei; Chen, Miaomiao

2017-09-05

Hydride generation (HG) is an effective technique that eliminates interfering matrix species and enables hydride separation. Arsenic speciation analysis can be fulfilled by cryogenic trapping (CT) based on boiling points of resulting arsines using liquid nitrogen (LN 2 ) as a coolant. In this work, LN 2 was replaced by the thermoelectric effect using a cryogenic trap that consisted of a polytetrafluoroethylene (PTFE) body sandwiched by two Peltier modules. After the trap was precooled, the arsines flew along a zigzag channel in the body and reached a sorbent bed of 0.2 g of 15% OV-3 on Chromosorb W-AW-DMCS imbedded near the exit of the trap. CH 3 AsH 2 and (CH 3 ) 2 AsH were trapped, while AsH 3 , that passed the trap unaffected, was detected by atomic fluorescence spectrometry. Continuous operation led to enhanced throughput. For inorganic As, the limit of detection (LOD) was 1.1 ng/g and recovery was 101.0 ± 1.1%. Monomethylarsonic acid and dimethylarsinic acid did not interfere with 0.2 ± 1.2% and -0.3 ± 0.5% recoveries, respectively.

Prominence Bubble Shear Flows and the Coupled Kelvin-Helmholtz — Rayleigh-Taylor Instability

Science.gov (United States)

Berger, Thomas; Hillier, Andrew

2017-08-01

Prominence bubbles are large arched structures that rise from below into quiescent prominences, often growing to heights on the order of 10 Mm before going unstable and generating plume upflows. While there is general agreement that emerging flux below pre-existing prominences causes the structures, there is lack of agreement on the nature of the bubbles and the cause of the instability flows. One hypothesis is that the bubbles contain coronal temperature plasma and rise into the prominence above due to both magnetic and thermal buoyancy, eventually breaking down via a magnetic Rayleigh-Taylor (RT) instability to release hot plasma and magnetic flux and helicity into the overlying coronal flux rope. Another posits that the bubbles are actually just “arcades” in the prominence indicating a magnetic separator line between the bipole and the prominence fields with the observed upflows and downflows caused by reconnection along the separator. We analyze Hinode/SOT, SDO/AIA, and IRIS observations of prominence bubbles, focusing on characteristics of the bubble boundary layers that may discriminate between the two hypotheses. We find speeds on the order of 10 km/s in prominence plasma downflows and lateral shear flows along the bubble boundary. Inflows to the boundary gradually increase the thickness and brightness of the layer until plasma drains from there, apparently around the dome-like bubble domain. In one case, shear flow across the bubble boundary develops Kelvin-Helmholtz (KH) vortices that we use to infer flow speeds in the low-density bubble on the order of 100 km/sec. IRIS spectra indicate that plasma flows on the bubble boundary at transition region temperatures achieve Doppler speeds on the order of 50 km/s, consistent with this inference. Combined magnetic KH-RT instability analysis leads to flux density estimates of 10 G with a field angle of 30° to the prominence, consistent with vector magnetic field measurements. In contrast, we find no evidence

Eruptive prominences and long-delay geomagnetic storms

International Nuclear Information System (INIS)

Wright, C.S.

1983-01-01

The relationship between disappearing solar fragments and geomagnetic disturbances was investigated. It is shown that long-delay storms are associated with filaments well removed from the disc centre, and particularly in the case of large filaments and prominences, the proportion of events that produce long-delay storms increases with angular distance from the centre

Trapping tsetse flies on water

Directory of Open Access Journals (Sweden)

Laveissière C.

2011-05-01

Full Text Available Riverine tsetse flies such as Glossina palpalis gambiensis and G. tachinoides are the vectors of human and animal trypanosomoses in West Africa. Despite intimate links between tsetse and water, to our knowledge there has never been any attempt to design trapping devices that would catch tsetse on water. In mangrove (Guinea one challenging issue is the tide, because height above the ground for a trap is a key factor affecting tsetse catches. The trap was mounted on the remains of an old wooden dugout, and attached with rope to nearby branches, thereby allowing it to rise and fall with the tide. Catches showed a very high density of 93.9 flies/”water-trap”/day, which was significantly higher (p < 0.05 than all the catches from other habitats where the classical trap had been used. In savannah, on the Comoe river of South Burkina Faso, the biconical trap was mounted on a small wooden raft anchored to a stone, and catches were compared with the classical biconical trap put on the shores. G. p. gambiensis and G. tachinoides densities were not significantly different from those from the classical biconical one. The adaptations described here have allowed to efficiently catch tsetse on the water, which to our knowledge is reported here for the first time. This represents a great progress and opens new opportunities to undertake studies on the vectors of trypanosomoses in mangrove areas of Guinea, which are currently the areas showing the highest prevalences of sleeping sickness in West Africa. It also has huge potential for tsetse control using insecticide impregnated traps in savannah areas where traps become less efficient in rainy season. The Guinean National control programme has already expressed its willingness to use such modified traps in its control campaigns in Guinea, as has the national PATTEC programme in Burkina Faso during rainy season.

Controlling trapping potentials and stray electric fields in a microfabricated ion trap through design and compensation

International Nuclear Information System (INIS)

Charles Doret, S; Amini, Jason M; Wright, Kenneth; Volin, Curtis; Killian, Tyler; Ozakin, Arkadas; Denison, Douglas; Hayden, Harley; Pai, C-S; Slusher, Richart E; Harter, Alexa W

2012-01-01

Recent advances in quantum information processing with trapped ions have demonstrated the need for new ion trap architectures capable of holding and manipulating chains of many (>10) ions. Here we present the design and detailed characterization of a new linear trap, microfabricated with scalable complementary metal-oxide-semiconductor (CMOS) techniques, that is well-suited to this challenge. Forty-four individually controlled dc electrodes provide the many degrees of freedom required to construct anharmonic potential wells, shuttle ions, merge and split ion chains, precisely tune secular mode frequencies, and adjust the orientation of trap axes. Microfabricated capacitors on dc electrodes suppress radio-frequency pickup and excess micromotion, while a top-level ground layer simplifies modeling of electric fields and protects trap structures underneath. A localized aperture in the substrate provides access to the trapping region from an oven below, permitting deterministic loading of particular isotopic/elemental sequences via species-selective photoionization. The shapes of the aperture and radio-frequency electrodes are optimized to minimize perturbation of the trapping pseudopotential. Laboratory experiments verify simulated potentials and characterize trapping lifetimes, stray electric fields, and ion heating rates, while measurement and cancellation of spatially-varying stray electric fields permits the formation of nearly-equally spaced ion chains. (paper)

Overcurrent Abuse of Primary Prismatic Zinc–Air Battery Cells Studying Air Supply Effects on Performance and Safety Shut-Down

Directory of Open Access Journals (Sweden)

Fredrik Larsson

2017-01-01

Full Text Available Overcurrent abuse has been performed on commercial 48 Ah primary prismatic zinc (Zn–Air battery cells with full air supply as well as with shut-off air supply. Compared to other battery technologies, e.g., lithium-ion batteries, metal–air batteries offer the possibility to physically stop the battery operation by stopping its air supply, thus offering an additional protection against severe battery damage in the case of, e.g., an accidental short circuit. This method may also reduce the electrical hazard in a larger battery system since, by stopping the air supply, the voltage can be brought to zero while maintaining the energy capacity of the battery. Measurements of overdischarge currents and current cut-off by suffocation have been performed to assess the safety of this type of Zn–air battery. The time to get to zero battery voltage is shown to mainly be determined by the volume of air trapped in the cell.

Characteristics of single-atom trapping in a magneto-optical trap with a high magnetic-field gradient

International Nuclear Information System (INIS)

Yoon, Seokchan; Choi, Youngwoon; Park, Sangbum; Ji, Wangxi; Lee, Jai-Hyung; An, Kyungwon

2007-01-01

A quantitative study on characteristics of a magneto-optical trap with a single or a few atoms is presented. A very small number of 85 Rb atoms were trapped in a micron-size magneto-optical trap with a high magnetic-field gradient. In order to find the optimum condition for a single-atom trap, we have investigated how the number of atoms and the size of atomic cloud change as various experimental parameters, such as a magnetic-field gradient and the trapping laser intensity and detuning. The averaged number of atoms was measured very accurately with a calibration procedure based on the single-atom saturation curve of resonance fluorescence. In addition, the number of atoms in a trap could be controlled by suppressing stochastic loading events by means of a real-time active feedback on the magnetic-field gradient

Sognenavne, Albertslund Kommune (3 artikler). trap.dk

DEFF Research Database (Denmark)

Kællerød, Lars-Jakob Harding

2019-01-01

Artikler til Trap Danmarks netpublikation trap.dk Sognenavnene Herstedvester, Herstedøster og Opstandelseskirkens Sogn......Artikler til Trap Danmarks netpublikation trap.dk Sognenavnene Herstedvester, Herstedøster og Opstandelseskirkens Sogn...

EUV lines observed with EIS/Hinode in a solar prominence

Science.gov (United States)

Labrosse, N.; Schmieder, B.; Heinzel, P.; Watanabe, T.

2011-07-01

Context. During a multi-wavelength observation campaign with Hinode and ground-based instruments, a solar prominence was observed for three consecutive days as it crossed the western limb of the Sun in April 2007. Aims: We report on observations obtained on 26 April 2007 using EIS (Extreme ultraviolet Imaging Spectrometer) on Hinode. They are analysed to provide a qualitative diagnostic of the plasma in different parts of the prominence. Methods: After correcting for instrumental effects, the rasters at different wavelengths are presented. Several regions within the same prominence are identified for further analysis. Selected profiles for lines with formation temperatures between log (T) = 4.7 and log (T) = 6.3, as well as their integrated intensities, are given. The profiles of coronal, transition region, and He ii lines are discussed. We pay special attention to the He ii line, which is blended with coronal lines. Results: Some quantitative results are obtained by analysing the line profiles. They confirm that depression in EUV lines can be interpreted in terms of two mechanisms: absorption of coronal radiation by the hydrogen and neutral helium resonance continua, and emissivity blocking. We present estimates of the He ii line integrated intensity in different parts of the prominence according to different scenarios for the relative contribution of absorption and emissivity blocking to the coronal lines blended with the He ii line. We estimate the contribution of the He ii 256.32 Å line to the He ii raster image to vary between ~44% and 70% of the raster's total intensity in the prominence according to the different models used to take into account the blending coronal lines. The inferred integrated intensities of the He ii 256 Å line are consistent with the theoretical intensities obtained with previous 1D non-LTE radiative transfer calculations, yielding a preliminary estimate of the central temperature of 8700 K, a central pressure of 0.33 dyn cm-2, and a

Observation of the Kelvin–Helmholtz Instability in a Solar Prominence

Science.gov (United States)

Yang, Heesu; Xu, Zhi; Lim, Eun-Kyung; Kim, Sujin; Cho, Kyung-Suk; Kim, Yeon-Han; Chae, Jongchul; Cho, Kyuhyoun; Ji, Kaifan

2018-04-01

Many solar prominences end their lives in eruptions or abrupt disappearances that are associated with dynamical or thermal instabilities. Such instabilities are important because they may be responsible for energy transport and conversion. We present a clear observation of a streaming kink-mode Kelvin–Helmholtz Instability (KHI) taking place in a solar prominence using the Hα Lyot filter installed at the New Vacuum Solar Telescope, Fuxian-lake Solar Observatory in Yunnan, China. On one side of the prominence, a series of plasma blobs floated up from the chromosphere and streamed parallel to the limb. The plasma stream was accelerated to about 20–60 km s‑1 and then undulated. We found that 2″- and 5″-size vortices formed, floated along the stream, and then broke up. After the 5″-size vortex, a plasma ejection out of the stream was detected in the Solar Dynamics Observatory/Atmospheric Imaging Assembly images. Just before the formation of the 5″-size vortex, the stream displayed an oscillatory transverse motion with a period of 255 s with the amplitude growing at the rate of 0.001 s‑1. We attribute this oscillation of the stream and the subsequent formation of the vortex to the KHI triggered by velocity shear between the stream, guided by the magnetic field and the surrounding media. The plasma ejection suggests the transport of prominence material into the upper layer by the KHI in its nonlinear stage.

Prominent Midlatitude Circulation Signature in High Asia's Surface Climate During Monsoon

Science.gov (United States)

Mölg, Thomas; Maussion, Fabien; Collier, Emily; Chiang, John C. H.; Scherer, Dieter

2017-12-01

High Asia has experienced strong environmental changes in recent decades, as evident in records of glaciers, lakes, tree rings, and vegetation. The multiscale understanding of the climatic drivers, however, is still incomplete. In particular, few systematic assessments have evaluated to what degree, if at all, the midlatitude westerly circulation modifies local surface climates in the reach of the Indian Summer Monsoon. This paper shows that a southward shift of the upper-tropospheric westerlies contributes significantly to climate variability in the core monsoon season (July-September) by two prominent dipole patterns at the surface: cooling in the west of High Asia contrasts with warming in the east, while moist anomalies in the east and northwest occur with drying along the southwestern margins. Circulation anomalies help to understand the dipoles and coincide with shifts in both the westerly wave train and the South Asian High, which imprint on air mass advection and local energy budgets. The relation of the variabilities to a well-established index of midlatitude climate dynamics allows future research on climate proxies to include a fresh hypothesis for the interpretation of environmental changes.

Optical traps with geometric aberrations

International Nuclear Information System (INIS)

Roichman, Yael; Waldron, Alex; Gardel, Emily; Grier, David G.

2006-01-01

We assess the influence of geometric aberrations on the in-plane performance of optical traps by studying the dynamics of trapped colloidal spheres in deliberately distorted holographic optical tweezers. The lateral stiffness of the traps turns out to be insensitive to moderate amounts of coma, astigmatism, and spherical aberration. Moreover holographic aberration correction enables us to compensate inherent shortcomings in the optical train, thereby adaptively improving its performance. We also demonstrate the effects of geometric aberrations on the intensity profiles of optical vortices, whose readily measured deformations suggest a method for rapidly estimating and correcting geometric aberrations in holographic trapping systems

Lines of MgI Detected in Solar Prominences

Czech Academy of Sciences Publication Activity Database

Heinzel, Petr; Kupryakov, Yu. A.; Schwartz, P.

2016-01-01

Roč. 40, č. 1 (2016), s. 87-91 ISSN 1845-8319. [Hvar Astrophysical Colloquium /14./. Hvar, 26.09.2016-30.09.2016] Institutional support: RVO:67985815 Keywords : prominences * limb-flare * MgI emession Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

WATER-TRAPPED WORLDS

International Nuclear Information System (INIS)

Menou, Kristen

2013-01-01

Although tidally locked habitable planets orbiting nearby M-dwarf stars are among the best astronomical targets to search for extrasolar life, they may also be deficient in volatiles and water. Climate models for this class of planets show atmospheric transport of water from the dayside to the nightside, where it is precipitated as snow and trapped as ice. Since ice only slowly flows back to the dayside upon accumulation, the resulting hydrological cycle can trap a large amount of water in the form of nightside ice. Using ice sheet dynamical and thermodynamical constraints, I illustrate how planets with less than about a quarter the Earth's oceans could trap most of their surface water on the nightside. This would leave their dayside, where habitable conditions are met, potentially dry. The amount and distribution of residual liquid water on the dayside depend on a variety of geophysical factors, including the efficiency of rock weathering at regulating atmospheric CO 2 as dayside ocean basins dry up. Water-trapped worlds with dry daysides may offer similar advantages as land planets for habitability, by contrast with worlds where more abundant water freely flows around the globe

WATER-TRAPPED WORLDS

Energy Technology Data Exchange (ETDEWEB)

Menou, Kristen [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)

2013-09-01

Although tidally locked habitable planets orbiting nearby M-dwarf stars are among the best astronomical targets to search for extrasolar life, they may also be deficient in volatiles and water. Climate models for this class of planets show atmospheric transport of water from the dayside to the nightside, where it is precipitated as snow and trapped as ice. Since ice only slowly flows back to the dayside upon accumulation, the resulting hydrological cycle can trap a large amount of water in the form of nightside ice. Using ice sheet dynamical and thermodynamical constraints, I illustrate how planets with less than about a quarter the Earth's oceans could trap most of their surface water on the nightside. This would leave their dayside, where habitable conditions are met, potentially dry. The amount and distribution of residual liquid water on the dayside depend on a variety of geophysical factors, including the efficiency of rock weathering at regulating atmospheric CO{sub 2} as dayside ocean basins dry up. Water-trapped worlds with dry daysides may offer similar advantages as land planets for habitability, by contrast with worlds where more abundant water freely flows around the globe.

Spin resonance with trapped ions

Energy Technology Data Exchange (ETDEWEB)

Wunderlich, Ch; Balzer, Ch; Hannemann, T; Mintert, F; Neuhauser, W; Reiss, D; Toschek, P E [Institut fuer Laser-Physik, Universitaet Hamburg, Jungiusstrasse 9, 20355 Hamburg (Germany)

2003-03-14

A modified ion trap is described where experiments (in particular related to quantum information processing) that usually require optical radiation can be carried out using microwave or radio frequency electromagnetic fields. Instead of applying the usual methods for coherent manipulation of trapped ions, a string of ions in such a modified trap can be treated like a molecule in nuclear magnetic resonance experiments taking advantage of spin-spin coupling. The collection of trapped ions can be viewed as an N-qubit molecule with adjustable spin-spin coupling constants. Given N identically prepared quantum mechanical two-level systems (qubits), the optimal strategy to estimate their quantum state requires collective measurements. Using the ground state hyperfine levels of electrodynamically trapped {sup 171}Yb{sup +}, we have implemented an adaptive algorithm for state estimation involving sequential measurements on arbitrary qubit states.

Spin resonance with trapped ions

International Nuclear Information System (INIS)

Wunderlich, Ch; Balzer, Ch; Hannemann, T; Mintert, F; Neuhauser, W; Reiss, D; Toschek, P E

2003-01-01

A modified ion trap is described where experiments (in particular related to quantum information processing) that usually require optical radiation can be carried out using microwave or radio frequency electromagnetic fields. Instead of applying the usual methods for coherent manipulation of trapped ions, a string of ions in such a modified trap can be treated like a molecule in nuclear magnetic resonance experiments taking advantage of spin-spin coupling. The collection of trapped ions can be viewed as an N-qubit molecule with adjustable spin-spin coupling constants. Given N identically prepared quantum mechanical two-level systems (qubits), the optimal strategy to estimate their quantum state requires collective measurements. Using the ground state hyperfine levels of electrodynamically trapped 171 Yb + , we have implemented an adaptive algorithm for state estimation involving sequential measurements on arbitrary qubit states

The hidden traps in decision making.

Science.gov (United States)

Hammond, J S; Keeney, R L; Raiffa, H

1998-01-01

Bad decisions can often be traced back to the way the decisions were made--the alternatives were not clearly defined, the right information was not collected, the costs and benefits were not accurately weighted. But sometimes the fault lies not in the decision-making process but rather in the mind of the decision maker. The way the human brain works can sabotage the choices we make. John Hammond, Ralph Keeney, and Howard Raiffa examine eight psychological traps that are particularly likely to affect the way we make business decisions: The anchoring trap leads us to give disproportionate weight to the first information we receive. The statusquo trap biases us toward maintaining the current situation--even when better alternatives exist. The sunk-cost trap inclines us to perpetuate the mistakes of the past. The confirming-evidence trap leads us to seek out information supporting an existing predilection and to discount opposing information. The framing trap occurs when we misstate a problem, undermining the entire decision-making process. The overconfidence trap makes us overestimate the accuracy of our forecasts. The prudence trap leads us to be overcautious when we make estimates about uncertain events. And the recallability trap leads us to give undue weight to recent, dramatic events. The best way to avoid all the traps is awareness--forewarned is forearmed. But executives can also take other simple steps to protect themselves and their organizations from the various kinds of mental lapses. The authors show how to take action to ensure that important business decisions are sound and reliable.

Characterization of the San Andreas Fault near Parkfield, California by fault-zone trapped waves

Science.gov (United States)

Li, Y.; Vidale, J.; Cochran, E.

2003-04-01

In October, 2002, coordinated by the Pre-EarthScope/SAFOD, we conducted an extensive seismic experiment at the San Andreas fault (SAF), Parkfield to record fault-zone trapped waves generated by explosions and microearthquakes using dense linear seismic arrays of 52 PASSCAL 3-channel REFTEKs deployed across and along the fault zone. We detonated 3 explosions within and out of the fault zone during the experiment, and also recorded other 13 shots of PASO experiment of UWM/RPI (Thurber and Roecker) detonated around the SAFOD drilling site at the same time. We observed prominent fault-zone trapped waves with large amplitudes and long duration following S waves at stations close to the main fault trace for sources located within and close to the fault zone. Dominant frequencies of trapped waves are 2-3 Hz for near-surface explosions and 4-5 Hz for microearthquakes. Fault-zone trapped waves are relatively weak on the north strand of SAF for same sources. In contrast, seismograms registered for both the stations and shots far away from the fault zone show a brief S wave and lack of trapped waves. These observations are consistent with previous findings of fault-zone trapped waves at the SAF [Li et al., 1990; 1997], indicating the existence of a well-developed low-velocity waveguide along the main fault strand (principal slip plan) of the SAF. The data from denser arrays and 3-D finite-difference simulations of fault-zone trapped waves allowed us to delineate the internal structure, segmentation and physical properties of the SAF with higher resolution. The trapped-wave inferred waveguide on the SAF Parkfield segment is ~150 m wide at surface and tapers to ~100 m at seismogenic depth, in which Q is 20-50 and S velocities are reduced by 30-40% from wall-rock velocities, with the greater velocity reduction at the shallow depth and to southeast of the 1966 M6 epicenter. We interpret this low-velocity waveguide on the SAF main strand as being the remnant of damage zone caused

Prominence and tornado dynamics observed with IRIS and THEMIS

Science.gov (United States)

Schmieder, Brigitte; Levens, Peter; Labrosse, Nicolas; Mein, Pierre; Lopez Ariste, Arturo; Zapior, Maciek

2017-08-01

Several prominences were observed during campaigns in September 2013 and July 2014 with the IRIS spectrometer and the vector magnetograph THEMIS (Tenerife). SDO/AIA and IRIS provided images and spectra of prominences and tornadoes corresponding to different physical conditions of the transition region between the cool plasma and the corona. The vector magnetic field was derived from THEMIS observations by using the He D3 depolarisation due to the magnetic field. The inversion code (PCA) takes into account the Hanle and Zeeman effects and allows us to compute the strength and the inclination of the magnetic field which is shown to be mostly horizontal in prominences as well as in tornadoes. Movies from SDO/AIA in 304 A and Hinode/SOT in Ca II show the highly dynamic nature of the fine structures. From spectra in Mg II and Si IV lines provided by IRIS and H-alpha observed by the Multi-channel Subtractive Double Pass (MSDP) spectrograph in the Meudon Solar Tower we derived the Doppler shifts of the fine structures and reconstructed the 3D structure of tornadoes. We conclude that the apparent rotation of AIA tornadoes is due to large-scale quasi-periodic oscillations of the plasma along more or less horizontal magnetic structures.

Črna Jama as a cold air trap cave within Postojna Cave, Slovenia

Science.gov (United States)

Šebela, Stanka; Turk, Janez

2017-10-01

Črna Jama is the coldest section of cave within the Postojna Cave System. Mean annual air temperatures at the Črna Jama 2 site are 5.6 °C (2015) and 5.7 °C (2016), and at the Črna Jama 3 site 7.1 °C (2015) and 7.2 (2016), whereas the mean external air temperature was 10.3 °C (2015) and 10.0 °C (2016). In Lepe Jame, the passage most heavily visited by tourists, the mean cave-air temperature is 10.7 °C (2014-2017). Črna Jama exhibits winter and summer temperature regimes. During warm periods (Tcave Tout), ventilation takes place and dense, cold, outside air sinks into Črna Jama because of the favourable cave entrance morphology. Recent Črna Jama air temperature data (2014-2017) indicate a < 0.5 °C higher temperature than that recorded in historical data since 1933. Črna Jama is the most appropriate place within the Postojna Cave System to study long-term climatic changes. There are hardly any tourist visits to the cave, and human impacts on the cave climate are essentially reduced.

Measurement and simulation of the pressure ratio between the two traps of double Penning trap mass spectrometers

International Nuclear Information System (INIS)

Neidherr, D.; Blaum, K.; Block, M.; Ferrer, R.; Herfurth, F.; Ketelaer, J.; Nagy, Sz.; Weber, C.

2008-01-01

Penning traps are ideal tools to perform high-precision mass measurements. For this purpose the cyclotron frequency of the stored charged particles is measured. In case of on-line mass measurements of short-lived nuclides produced at radioactive beam facilities the ions get in general first prepared and cooled by buffer-gas collisions in a preparation trap to reduce their motional amplitudes and are then transported to a precision trap for the cyclotron frequency determination. In modern Penning trap mass spectrometers both traps are placed in the homogeneous region of one superconducting magnet to optimize the transport efficiency. Because the gas pressure inside the precision trap has to be very low in order to minimize the damping of the ion motion caused by collisions with rest gas molecules during the frequency determination, a pumping barrier is installed between both traps. To predict the pressure difference between the two traps in the region of molecular gas flow the motion of each particle can be simulated without consideration of the other particles. Thus, it is possible to calculate the transit probability through a tube of a given geometry. The results are compared with experimentally obtained pressure differences.

A twisted flux-tube model for solar prominences. I. General properties

International Nuclear Information System (INIS)

Priest, E.R.; Hood, A.W.; Anzer, U.

1989-01-01

It is proposed that a solar prominence consists of cool plasma supported in a large-scale curved and twisted magnetic flux tube. As long as the flux tube is untwisted, its curvature is concave toward the solar surface, and so it cannot support dense plasma against gravity. However, when it is twisted sufficiently, individual field lines may acquire a convex curvature near their summits and so provide support. Cool plasma then naturally tends to accumulate in such field line dips either by injection from below or by thermal condensation. As the tube is twisted up further or reconnection takes place below the prominence, one finds a transition from normal to inverse polarity. When the flux tube becomes too long or is twisted too much, it loses stability and its true magnetic geometry as an erupting prominence is revealed more clearly. 56 refs

Temperature dependence of trapping effects in metal gates/Al2O3/InGaAs stacks

Science.gov (United States)

Palumbo, F.; Pazos, S.; Aguirre, F.; Winter, R.; Krylov, I.; Eizenberg, M.

2017-06-01

The influence of the temperature on Metal Gate/Al2O3/n-InGaAs stacks has been studied by means of capacitance-voltage (C-V) hysteresis and flat band voltage as function of both negative and positive stress fields. It was found that the de-trapping effect decreases at low-temperature, indicating that the de-trapping of trapped electrons from oxide traps may be performed via Al2O3/InGaAs interface defects. The dependence of the C-V hysteresis on the stress field at different temperatures in our InGaAs stacks can be explained in terms of the defect spatial distribution. An oxide defect distribution can be found very close to the metal gate/Al2O3 interface. On the other side, the Al2O3/InGaAs interface presents defects distributed from the interface into the bulk of the oxide, showing the influence of InGaAs on Al2O3 in terms of the spatial defect distribution. At the present, he is a research staff of the National Council of Science and Technology (CONICET), working in the National Commission of Atomic Energy (CNEA) in Buenos Aires, Argentina, well embedded within international research collaboration. Since 2008, he is Professor at the National Technological University (UTN) in Buenos Aires, Argentina. Dr. Palumbo has received research fellowships from: Marie Curie Fellowship within the 7th European Community Framework Programme, Abdus Salam International Centre for Theoretical Physics (ICTP) Italy, National Council of Science and Technology (CONICET) Argentina, and Consiglio Nazionale delle Ricerche (CNR) Italy. He is also a frequent scientific visitor of academic institutions as IMM-CNR-Italy, Minatec Grenoble-France, the Autonomous University of Barcelona-Spain, and the Israel Institute of Technology-Technion. He has authored and co-authored more than 50 papers in international conferences and journals.

Microfabricated Waveguide Atom Traps.

Energy Technology Data Exchange (ETDEWEB)

Jau, Yuan-Yu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-09-01

A nanoscale , microfabricated waveguide structure can in - principle be used to trap atoms in well - defined locations and enable strong photon-atom interactions . A neutral - atom platform based on this microfabrication technology will be prealigned , which is especially important for quantum - control applications. At present, there is still no reported demonstration of evanescent - field atom trapping using a microfabricated waveguide structure. We described the capabilities established by our team for future development of the waveguide atom - trapping technology at SNL and report our studies to overcome the technical challenges of loading cold atoms into the waveguide atom traps, efficient and broadband optical coupling to a waveguide, and the waveguide material for high - power optical transmission. From the atomic - physics and the waveguide modeling, w e have shown that a square nano-waveguide can be utilized t o achieve better atomic spin squeezing than using a nanofiber for first time.

DYNAMICS OF A PROMINENCE-HORN STRUCTURE DURING ITS EVAPORATION IN THE SOLAR CORONA

Energy Technology Data Exchange (ETDEWEB)

Wang, Bing; Chen, Yao; Fu, Jie; Li, Bo [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, and Institute of Space Sciences, Shandong University, Weihai 264209 (China); Li, Xing [Department of Physics, Aberystwyth University, Aberystwyth, Ceredigion, SY23 3BZ (United Kingdom); Liu, Wei, E-mail: yaochen@sdu.edu.cn [Stanford-Lockheed Institute for Space Research, Stanford University, Stanford, CA 94305 (United States)

2016-08-20

The physical connections among and formation mechanisms of various components of the prominence-horn cavity system remain elusive. Here we present observations of such a system, focusing on a section of the prominence that rises and separates gradually from the main body. This forms a configuration sufficiently simple to yield clues regarding the above issues. It is characterized by embedding horns, oscillations, and a gradual disappearance of the separated material. The prominence-horn structure exhibits a large-amplitude longitudinal oscillation with a period of ∼150 minutes and an amplitude of ∼30 Mm along the trajectory defined by the concave horn structure. The horns also experience a simultaneous transverse oscillation with a much smaller amplitude (∼3 Mm) and a shorter period (∼10–15 minutes), likely representative of a global mode of the large-scale magnetic structure. The gradual disappearance of the structure indicates that the horn, an observational manifestation of the field-aligned transition region separating the cool and dense prominence from the hot and tenuous corona, is formed due to the heating and diluting process of the central prominence mass; most previous studies suggested that it is the opposite process, i.e., the cooling and condensation of coronal plasmas, that formed the horn. This study also demonstrates how the prominence transports magnetic flux to the upper corona, a process essential for the gradual build-up of pre-eruption magnetic energy.

Laser-cooling and electromagnetic trapping of neutral atoms

International Nuclear Information System (INIS)

Phillips, W.D.; Migdall, A.L.; Metcalf, H.J.

1986-01-01

Until recently it has been impossible to confine and trap neutral atoms using electromagnetic fields. While many proposals for such traps exist, the small potential energy depth of the traps and the high kinetic energy of available atoms prevented trapping. We review various schemes for atom trapping, the advances in laser cooling of atomic beams which have now made trapping possible, and the successful magnetic trapping of cold sodium atoms

ARE GIANT TORNADOES THE LEGS OF SOLAR PROMINENCES?

Energy Technology Data Exchange (ETDEWEB)

Wedemeyer, Sven; Scullion, Eamon; Rouppe van der Voort, Luc; Bosnjak, Antonija [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Antolin, Patrick, E-mail: sven.wedemeyer@astro.uio.no [Centre for Mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, bus 2400, B-3001 Leuven (Belgium)

2013-09-10

Observations in the 171 A channel of the Atmospheric Imaging Assembly of the space-borne Solar Dynamics Observatory show tornado-like features in the atmosphere of the Sun. These giant tornadoes appear as dark, elongated, and apparently rotating structures in front of a brighter background. This phenomenon is thought to be produced by rotating magnetic field structures that extend throughout the atmosphere. We characterize giant tornadoes through a statistical analysis of properties such as spatial distribution, lifetimes, and sizes. A total number of 201 giant tornadoes are detected in a period of 25 days, suggesting that, on average, about 30 events are present across the whole Sun at a time close to solar maximum. Most tornadoes appear in groups and seem to form the legs of prominences, thus serving as plasma sources/sinks. Additional H{alpha} observations with the Swedish 1 m Solar Telescope imply that giant tornadoes rotate as a structure, although they clearly exhibit a thread-like structure. We observe tornado groups that grow prior to the eruption of the connected prominence. The rotation of the tornadoes may progressively twist the magnetic structure of the prominence until it becomes unstable and erupts. Finally, we investigate the potential relation of giant tornadoes to other phenomena, which may also be produced by rotating magnetic field structures. A comparison to cyclones, magnetic tornadoes, and spicules implies that such events are more abundant and short-lived the smaller they are. This comparison might help to construct a power law for the effective atmospheric heating contribution as a function of spatial scale.

ARE GIANT TORNADOES THE LEGS OF SOLAR PROMINENCES?

International Nuclear Information System (INIS)

Wedemeyer, Sven; Scullion, Eamon; Rouppe van der Voort, Luc; Bosnjak, Antonija; Antolin, Patrick

2013-01-01

Observations in the 171 Å channel of the Atmospheric Imaging Assembly of the space-borne Solar Dynamics Observatory show tornado-like features in the atmosphere of the Sun. These giant tornadoes appear as dark, elongated, and apparently rotating structures in front of a brighter background. This phenomenon is thought to be produced by rotating magnetic field structures that extend throughout the atmosphere. We characterize giant tornadoes through a statistical analysis of properties such as spatial distribution, lifetimes, and sizes. A total number of 201 giant tornadoes are detected in a period of 25 days, suggesting that, on average, about 30 events are present across the whole Sun at a time close to solar maximum. Most tornadoes appear in groups and seem to form the legs of prominences, thus serving as plasma sources/sinks. Additional Hα observations with the Swedish 1 m Solar Telescope imply that giant tornadoes rotate as a structure, although they clearly exhibit a thread-like structure. We observe tornado groups that grow prior to the eruption of the connected prominence. The rotation of the tornadoes may progressively twist the magnetic structure of the prominence until it becomes unstable and erupts. Finally, we investigate the potential relation of giant tornadoes to other phenomena, which may also be produced by rotating magnetic field structures. A comparison to cyclones, magnetic tornadoes, and spicules implies that such events are more abundant and short-lived the smaller they are. This comparison might help to construct a power law for the effective atmospheric heating contribution as a function of spatial scale

Optical Trapping of Ion Coulomb Crystals

Science.gov (United States)

Schmidt, Julian; Lambrecht, Alexander; Weckesser, Pascal; Debatin, Markus; Karpa, Leon; Schaetz, Tobias

2018-04-01

The electronic and motional degrees of freedom of trapped ions can be controlled and coherently coupled on the level of individual quanta. Assembling complex quantum systems ion by ion while keeping this unique level of control remains a challenging task. For many applications, linear chains of ions in conventional traps are ideally suited to address this problem. However, driven motion due to the magnetic or radio-frequency electric trapping fields sometimes limits the performance in one dimension and severely affects the extension to higher-dimensional systems. Here, we report on the trapping of multiple barium ions in a single-beam optical dipole trap without radio-frequency or additional magnetic fields. We study the persistence of order in ensembles of up to six ions within the optical trap, measure their temperature, and conclude that the ions form a linear chain, commonly called a one-dimensional Coulomb crystal. As a proof-of-concept demonstration, we access the collective motion and perform spectrometry of the normal modes in the optical trap. Our system provides a platform that is free of driven motion and combines advantages of optical trapping, such as state-dependent confinement and nanoscale potentials, with the desirable properties of crystals of trapped ions, such as long-range interactions featuring collective motion. Starting with small numbers of ions, it has been proposed that these properties would allow the experimental study of many-body physics and the onset of structural quantum phase transitions between one- and two-dimensional crystals.

Morphology Of A Hot Prominence Cavity Observed with Hinode/XRT and SDO/AIA

Science.gov (United States)

Weber, Mark A.; Reeves, K. K.; Gibson, S. E.; Kucera, T. A.

2012-01-01

Prominence cavities appear as circularly shaped voids in coronal emission over polarity inversion lines where a prominence channel is straddling the solar limb. The presence of chromospheric material suspended at coronal altitudes is a common but not necessary feature within these cavities. These voids are observed to change shape as a prominence feature rotates around the limb. We use a morphological model projected in cross-sections to fit the cavity emission in Hinode/XRT passbands, and then apply temperature diagnostics to XRT and SDO/AIA data to investigate the thermal structure. We find significant evidence that the prominence cavity is hotter than the corona immediately outside the cavity boundary. This investigation follows upon "Thermal Properties of A Solar Coronal Cavity Observed with the X-ray Telescope on Hinode" by Reeves et al., 2012, ApJ, in press.

Ball-grid array architecture for microfabricated ion traps

Science.gov (United States)

Guise, Nicholas D.; Fallek, Spencer D.; Stevens, Kelly E.; Brown, K. R.; Volin, Curtis; Harter, Alexa W.; Amini, Jason M.; Higashi, Robert E.; Lu, Son Thai; Chanhvongsak, Helen M.; Nguyen, Thi A.; Marcus, Matthew S.; Ohnstein, Thomas R.; Youngner, Daniel W.

2015-05-01

State-of-the-art microfabricated ion traps for quantum information research are approaching nearly one hundred control electrodes. We report here on the development and testing of a new architecture for microfabricated ion traps, built around ball-grid array (BGA) connections, that is suitable for increasingly complex trap designs. In the BGA trap, through-substrate vias bring electrical signals from the back side of the trap die to the surface trap structure on the top side. Gold-ball bump bonds connect the back side of the trap die to an interposer for signal routing from the carrier. Trench capacitors fabricated into the trap die replace area-intensive surface or edge capacitors. Wirebonds in the BGA architecture are moved to the interposer. These last two features allow the trap die to be reduced to only the area required to produce trapping fields. The smaller trap dimensions allow tight focusing of an addressing laser beam for fast single-qubit rotations. Performance of the BGA trap as characterized with 40Ca+ ions is comparable to previous surface-electrode traps in terms of ion heating rate, mode frequency stability, and storage lifetime. We demonstrate two-qubit entanglement operations with 171Yb+ ions in a second BGA trap.

Ball-grid array architecture for microfabricated ion traps

International Nuclear Information System (INIS)

Guise, Nicholas D.; Fallek, Spencer D.; Stevens, Kelly E.; Brown, K. R.; Volin, Curtis; Harter, Alexa W.; Amini, Jason M.; Higashi, Robert E.; Lu, Son Thai; Chanhvongsak, Helen M.; Nguyen, Thi A.; Marcus, Matthew S.; Ohnstein, Thomas R.; Youngner, Daniel W.

2015-01-01

State-of-the-art microfabricated ion traps for quantum information research are approaching nearly one hundred control electrodes. We report here on the development and testing of a new architecture for microfabricated ion traps, built around ball-grid array (BGA) connections, that is suitable for increasingly complex trap designs. In the BGA trap, through-substrate vias bring electrical signals from the back side of the trap die to the surface trap structure on the top side. Gold-ball bump bonds connect the back side of the trap die to an interposer for signal routing from the carrier. Trench capacitors fabricated into the trap die replace area-intensive surface or edge capacitors. Wirebonds in the BGA architecture are moved to the interposer. These last two features allow the trap die to be reduced to only the area required to produce trapping fields. The smaller trap dimensions allow tight focusing of an addressing laser beam for fast single-qubit rotations. Performance of the BGA trap as characterized with 40 Ca + ions is comparable to previous surface-electrode traps in terms of ion heating rate, mode frequency stability, and storage lifetime. We demonstrate two-qubit entanglement operations with 171 Yb + ions in a second BGA trap

Multi-Wavelength Eclipse Observations of a Quiescent Prominence

Czech Academy of Sciences Publication Activity Database

Jejčič, S.; Heinzel, Petr; Zapiór, M.; Druckmüller, M.; Gunár, Stanislav; Kotrč, Pavel

2014-01-01

Roč. 289, č. 7 (2014), s. 2487-2501 ISSN 0038-0938 R&D Projects: GA ČR GAP209/12/0906 Institutional support: RVO:67985815 Keywords : eclipse observations * prominences * quiescent Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.039, year: 2014

Liquid metal cold trap

International Nuclear Information System (INIS)

Hundal, R.

1976-01-01

A cold trap assembly for removing impurities from a liquid metal is described. A hole between the incoming impure liquid metal and purified outgoing liquid metal acts as a continuous bleed means and thus prevents the accumulation of cover gases within the cold trap assembly

Precision mass measurements at THe-trap and the FSU trap

Energy Technology Data Exchange (ETDEWEB)

Hoecker, Martin Juergen

2016-07-26

THe-Trap is a Penning-trap mass spectrometer at the Max-Planck-Institute for Nuclear Physics in Heidelberg, Germany, that aims to measure the T/{sup 3}He mass ratio with a relative uncertainty of 10{sup -11}. Improvements of the measurement technique, in particular the measurement of systematic shifts, enabled measurements of mass ratios with relative uncertainties of 7.10{sup -11}, as demonstrated by a cyclotron frequency ratio determination on {sup 12}C{sup 4+}/{sup 16}O{sup 5+}. This uncertainty was limited by the lineshape. An improved theoretical model based on a rotating wave approximation can be used to describe dynamical interactions between the detection system and the ion, in order to better understand the lineshape and to further reduce the uncertainty. The Florida State University trap is a Penning-trap mass spectrometer located in Tallahassee, Florida (USA). In the context of this thesis, three mass ratios were measured, and further 20 mass ratio measurements analyzed, which resulted in the publication of the masses of {sup 82,83}Kr, {sup 131,134}Xe, {sup 86-88}Sr, and {sup 170-174,176}Yb with relative uncertainties between (0.9 - 1.3).10{sup -10}. These masses serve as reference masses for other experiments and have applications in the determination of the fine-structure constant alpha via the photon-recoil method.

Electron trapping during irradiation in reoxidized nitrided oxide

International Nuclear Information System (INIS)

Mallik, A.; Vasi, J.; Chandorkar, A.N.

1993-01-01

Isochronal detrapping experiments have been performed following irradiation under different gate biases in reoxidized nitrided oxide (RNO) MOS capacitors. These show electron trapping by the nitridation-induced electron traps at low oxide fields during irradiation. A difference in the detrapping behavior of trapped holes and electrons is observed, with trapped holes being detrapped at relatively lower temperatures compared to trapped electrons. Electron trapping shows a strong dependence on tile magnitude of the applied gate bias during irradiation but is independent of its polarity. Conventional oxide devices, as expected, do not show any electron trapping during irradiation by the native electron traps. Finally, a comparison of the isochronal detrapping behavior following irradiation and following avalanche injection of electrons has been made to estimate the extent of electron trapping. The results show that electron trapping by the nitridation-induced electron traps does not play the dominant role in improving radiation performance of RNO, though its contribution cannot be completely neglected for low oxide field irradiations

HELICAL MOTIONS OF FINE-STRUCTURE PROMINENCE THREADS OBSERVED BY HINODE AND IRIS

Energy Technology Data Exchange (ETDEWEB)

Okamoto, Takenori J. [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Liu, Wei [Bay Area Environmental Research Institute, 625 2nd Street, Suite 209, Petaluma, CA 94952 (United States); Tsuneta, Saku, E-mail: joten.okamoto@nao.ac.jp [ISAS/JAXA, Sagamihara, Kanagawa 252-5210 (Japan)

2016-11-10

Fine-structure dynamics in solar prominences holds critical clues to understanding their physical nature of significant space-weather implications. We report evidence of rotational motions of horizontal helical threads in two active-region prominences observed by the Hinode and/or Interface Region Imaging Spectrograph satellites at high resolution. In the first event, we found transverse motions of brightening threads at speeds up to 55 km s{sup -1} seen in the plane of the sky. Such motions appeared as sinusoidal space–time trajectories with a typical period of ∼390 s, which is consistent with plane-of-sky projections of rotational motions. Phase delays at different locations suggest the propagation of twists along the threads at phase speeds of 90–270 km s{sup -1}. At least 15 episodes of such motions occurred in two days, none associated with an eruption. For these episodes, the plane-of-sky speed is linearly correlated with the vertical travel distance, suggestive of a constant angular speed. In the second event, we found Doppler velocities of 30–40 km s{sup -1} in opposite directions in the top and bottom portions of the prominence, comparable to the plane-of-sky speed. The moving threads have about twice broader line widths than stationary threads. These observations, when taken together, provide strong evidence for rotations of helical prominence threads, which were likely driven by unwinding twists triggered by magnetic reconnection between twisted prominence magnetic fields and ambient coronal fields.

Liking goes with liking: An intuitive congruence between preference and prominence.

Science.gov (United States)

Morvinski, Coby; Amir, On

2018-03-26

In a series of 8 experiments, we demonstrate the existence of a "labeling effect" wherein people intuitively relate preferred choices to prominently labeled cues (such as heads as opposed to tails in a coin toss) and vice versa. Importantly, the observed congruence is asymmetric-it does not manifest for nonprominent cues and nonpreferred choices. This is because the congruence is driven by a process of evaluative matching: prominent cues are liked, but nonprominent cues are neutral or at most slightly negative in contrast. When we test prominent, yet truly negatively labeled cues, we indeed find a matching with less liked products. We discuss the theoretical contributions to the study of preferences and decision making, as well as demonstrate the practical implications to researchers and practitioners by using this process to assess intuitive preferences and reduce the compromise effect. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Topics and topic prominence in two sign languages

NARCIS (Netherlands)

Kimmelman, V.

2015-01-01

In this paper we describe topic marking in Russian Sign Language (RSL) and Sign Language of the Netherlands (NGT) and discuss whether these languages should be considered topic prominent. The formal markers of topics in RSL are sentence-initial position, a prosodic break following the topic, and

Trapping Triatominae in Silvatic Habitats

Directory of Open Access Journals (Sweden)

Noireau François

2002-01-01

Full Text Available Large-scale trials of a trapping system designed to collect silvatic Triatominae are reported. Live-baited adhesive traps were tested in various ecosystems and different triatomine habitats (arboreal and terrestrial. The trials were always successful, with a rate of positive habitats generally over 20% and reaching 48.4% for palm trees of the Amazon basin. Eleven species of Triatominae belonging to the three genera of public health importance (Triatoma, Rhodnius and Panstrongylus were captured. This trapping system provides an effective way to detect the presence of triatomines in terrestrial and arboreal silvatic habitats and represents a promising tool for ecological studies. Various lines of research are contemplated to improve the performance of this trapping system.

Optical Trapping of Ion Coulomb Crystals

Directory of Open Access Journals (Sweden)

Julian Schmidt

2018-05-01

Full Text Available The electronic and motional degrees of freedom of trapped ions can be controlled and coherently coupled on the level of individual quanta. Assembling complex quantum systems ion by ion while keeping this unique level of control remains a challenging task. For many applications, linear chains of ions in conventional traps are ideally suited to address this problem. However, driven motion due to the magnetic or radio-frequency electric trapping fields sometimes limits the performance in one dimension and severely affects the extension to higher-dimensional systems. Here, we report on the trapping of multiple barium ions in a single-beam optical dipole trap without radio-frequency or additional magnetic fields. We study the persistence of order in ensembles of up to six ions within the optical trap, measure their temperature, and conclude that the ions form a linear chain, commonly called a one-dimensional Coulomb crystal. As a proof-of-concept demonstration, we access the collective motion and perform spectrometry of the normal modes in the optical trap. Our system provides a platform that is free of driven motion and combines advantages of optical trapping, such as state-dependent confinement and nanoscale potentials, with the desirable properties of crystals of trapped ions, such as long-range interactions featuring collective motion. Starting with small numbers of ions, it has been proposed that these properties would allow the experimental study of many-body physics and the onset of structural quantum phase transitions between one- and two-dimensional crystals.

Metabolic studies with NMR spectroscopy of the alga Dunaliella salina trapped within agarose beads.

Science.gov (United States)

Bental, M; Pick, U; Avron, M; Degani, H

1990-02-22

A technique for the entrapment of the unicellular algae Dunaliella salina in agarose beads and their perfusion during NMR measurements is presented. The trapped cells maintained their ability to proliferate under normal growth conditions, and remained viable and stable under steady-state conditions for long periods during NMR measurements. Following osmotic shock in the dark, prominent changes were observed in the intracellular level of ATP and polyphosphates, but little to no changes in the intracellular pH or orthoposphate content. When cells were subjected to hyperosmotic shock, the ATP level decreased. The content of NMR-visible polyphosphates decreased as well, presumably due to the production of longer, NMR-invisible structures. Following hypoosmotic shock, the ATP content increased and longer polyphosphates were broken down to shorter, more mobile polymers.

Performance improvement of charge trap flash memory by using a composition-modulated high-k trapping layer

International Nuclear Information System (INIS)

Tang Zhen-Jie; Li Rong; Yin Jiang

2013-01-01

A composition-modulated (HfO 2 ) x (Al 2 O3) 1−x charge trapping layer is proposed for charge trap flash memory by controlling the Al atom content to form a peak and valley shaped band gap. It is found that the memory device using the composition-modulated (HfO 2 ) x (Al 2 O 3 ) 1−x as the charge trapping layer exhibits a larger memory window of 11.5 V, improves data retention even at high temperature, and enhances the program/erase speed. Improvements of the memory characteristics are attributed to the special band-gap structure resulting from the composition-modulated trapping layer. Therefore, the composition-modulated charge trapping layer may be useful in future nonvolatile flash memory device application. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Science, conservation, and camera traps

Science.gov (United States)

Nichols, James D.; Karanth, K. Ullas; O'Connel, Allan F.; O'Connell, Allan F.; Nichols, James D.; Karanth, K. Ullas

2011-01-01

Biologists commonly perceive camera traps as a new tool that enables them to enter the hitherto secret world of wild animals. Camera traps are being used in a wide range of studies dealing with animal ecology, behavior, and conservation. Our intention in this volume is not to simply present the various uses of camera traps, but to focus on their use in the conduct of science and conservation. In this chapter, we provide an overview of these two broad classes of endeavor and sketch the manner in which camera traps are likely to be able to contribute to them. Our main point here is that neither photographs of individual animals, nor detection history data, nor parameter estimates generated from detection histories are the ultimate objective of a camera trap study directed at either science or management. Instead, the ultimate objectives are best viewed as either gaining an understanding of how ecological systems work (science) or trying to make wise decisions that move systems from less desirable to more desirable states (conservation, management). Therefore, we briefly describe here basic approaches to science and management, emphasizing the role of field data and associated analyses in these processes. We provide examples of ways in which camera trap data can inform science and management.

The Electronic McPhail Trap

Science.gov (United States)

Potamitis, Ilyas; Rigakis, Iraklis; Fysarakis, Konstantinos

2014-01-01

Certain insects affect cultivations in a detrimental way. A notable case is the olive fruit fly (Bactrocera oleae (Rossi)), that in Europe alone causes billions of euros in crop-loss/per year. Pests can be controlled with aerial and ground bait pesticide sprays, the efficiency of which depends on knowing the time and location of insect infestations as early as possible. The inspection of traps is currently carried out manually. Automatic monitoring traps can enhance efficient monitoring of flying pests by identifying and counting targeted pests as they enter the trap. This work deals with the hardware setup of an insect trap with an embedded optoelectronic sensor that automatically records insects as they fly in the trap. The sensor responsible for detecting the insect is an array of phototransistors receiving light from an infrared LED. The wing-beat recording is based on the interruption of the emitted light due to the partial occlusion from insect's wings as they fly in the trap. We show that the recordings are of high quality paving the way for automatic recognition and transmission of insect detections from the field to a smartphone. This work emphasizes the hardware implementation of the sensor and the detection/counting module giving all necessary implementation details needed to construct it. PMID:25429412

Cavity sideband cooling of trapped molecules

NARCIS (Netherlands)

Kowalewski, Markus; Morigi, Giovanna; Pinkse, Pepijn Willemszoon Harry; de Vivie-Riedle, Regina

2011-01-01

The efficiency of cavity sideband cooling of trapped molecules is theoretically investigated for the case in which the infrared transition between two rovibrational states is used as a cycling transition. The molecules are assumed to be trapped either by a radiofrequency or optical trapping

Class of analytic solutions for the thermally balanced magnetostatic prominence sheet

International Nuclear Information System (INIS)

Low, B.C.; Wu, S.T.

1981-01-01

This is a theoretical study of the nonlinear interplay between magnetostatic equilibrium and energy balance in a Kippenhahn-Schlueter type prominence sheet. The basic effects are illustrated explicitly with an analytic model in which a radiative loss proportional to rho 2 T balances against wave heating proportional to rho, with thermal conduction confined along magnetic field lines, where rho and T denote the plasma density and temperature, respectively. The particular choices of heat sink and source enable us to integrate the governing equations exactly while they are of the basic mathematical forms to simulate radiative loss in an optically thin plasma which is heated by wave dissipation. The steady solutions exhibit three different basic behaviors, characterized by the total wave heating in the prominence sheet being more than, equal to, or less than the total radiative loss. It is the compaction of the plasma along the field lines under its own weight combined with the effects of energy transport that determines which of the three basic behaviors obtains in a particular situation. The implications of the steady solutions for the formation of prominences are discussed. The exact solutions presented do not support the conclusion of Milne, Priest, and Roberts that there is an upper bound on the plasma beta for an equilibrium of the Kippenhahn-Schlueter prominence

Single-molecule dynamics in nanofabricated traps

Science.gov (United States)

Cohen, Adam

2009-03-01

The Anti-Brownian Electrokinetic trap (ABEL trap) provides a means to immobilize a single fluorescent molecule in solution, without surface attachment chemistry. The ABEL trap works by tracking the Brownian motion of a single molecule, and applying feedback electric fields to induce an electrokinetic motion that approximately cancels the Brownian motion. We present a new design for the ABEL trap that allows smaller molecules to be trapped and more information to be extracted from the dynamics of a single molecule than was previously possible. In particular, we present strategies for extracting dynamically fluctuating mobilities and diffusion coefficients, as a means to probe dynamic changes in molecular charge and shape. If one trapped molecule is good, many trapped molecules are better. An array of single molecules in solution, each immobilized without surface attachment chemistry, provides an ideal test-bed for single-molecule analyses of intramolecular dynamics and intermolecular interactions. We present a technology for creating such an array, using a fused silica plate with nanofabricated dimples and a removable cover for sealing single molecules within the dimples. With this device one can watch the shape fluctuations of single molecules of DNA or study cooperative interactions in weakly associating protein complexes.

Quiescent and Eruptive Prominences at Solar Minimum: A Statistical Study via an Automated Tracking System

Science.gov (United States)

Loboda, I. P.; Bogachev, S. A.

2015-07-01

We employ an automated detection algorithm to perform a global study of solar prominence characteristics. We process four months of TESIS observations in the He II 304Å line taken close to the solar minimum of 2008-2009 and mainly focus on quiescent and quiescent-eruptive prominences. We detect a total of 389 individual features ranging from 25×25 to 150×500 Mm2 in size and obtain distributions of many of their spatial characteristics, such as latitudinal position, height, size, and shape. To study their dynamics, we classify prominences as either stable or eruptive and calculate their average centroid velocities, which are found to rarely exceed 3 km/s. In addition, we give rough estimates of mass and gravitational energy for every detected prominence and use these values to estimate the total mass and gravitational energy of all simultaneously existing prominences (1012 - 1014 kg and 1029 - 1031 erg). Finally, we investigate the form of the gravitational energy spectrum of prominences and derive it to be a power-law of index -1.1 ± 0.2.

Physics with Trapped Antihydrogen

Science.gov (United States)

Charlton, Michael

2017-04-01

For more than a decade antihydrogen atoms have been formed by mixing antiprotons and positrons held in arrangements of charged particle (Penning) traps. More recently, magnetic minimum neutral atom traps have been superimposed upon the anti-atom production region, promoting the trapping of a small quantity of the antihydrogen yield. We will review these advances, and describe some of the first physics experiments performed on anrtihydrogen including the observation of the two-photon 1S-2S transition, invesigation of the charge neutrailty of the anti-atom and studies of the ground state hyperfine splitting. We will discuss the physics motivations for undertaking these experiments and describe some near-future initiatives.

Heating of an Erupting Prominence Associated with a Solar Coronal Mass Ejection on 2012 January 27

Energy Technology Data Exchange (ETDEWEB)

Lee, Jin-Yi; Moon, Yong-Jae; Kim, Kap-Sung [Department of Astronomy and Space Science, Kyung Hee University, Yongin-si, Gyeonggi-do, 17104 (Korea, Republic of); Raymond, John C.; Reeves, Katharine K. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

2017-07-20

We investigate the heating of an erupting prominence and loops associated with a coronal mass ejection and X-class flare. The prominence is seen as absorption in EUV at the beginning of its eruption. Later, the prominence changes to emission, which indicates heating of the erupting plasma. We find the densities of the erupting prominence using the absorption properties of hydrogen and helium in different passbands. We estimate the temperatures and densities of the erupting prominence and loops seen as emission features using the differential emission measure method, which uses both EUV and X-ray observations from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory and the X-ray Telescope on board Hinode . We consider synthetic spectra using both photospheric and coronal abundances in these calculations. We verify the methods for the estimation of temperatures and densities for the erupting plasmas. Then, we estimate the thermal, kinetic, radiative loss, thermal conduction, and heating energies of the erupting prominence and loops. We find that the heating of the erupting prominence and loop occurs strongly at early times in the eruption. This event shows a writhing motion of the erupting prominence, which may indicate a hot flux rope heated by thermal energy release during magnetic reconnection.

Observations of apparent superslow wave propagation in solar prominences

Science.gov (United States)

Raes, J. O.; Van Doorsselaere, T.; Baes, M.; Wright, A. N.

2017-06-01

Context. Phase mixing of standing continuum Alfvén waves and/or continuum slow waves in atmospheric magnetic structures such as coronal arcades can create the apparent effect of a wave propagating across the magnetic field. Aims: We observe a prominence with SDO/AIA on 2015 March 15 and find the presence of oscillatory motion. We aim to demonstrate that interpreting this motion as a magneto hydrodynamic (MHD) wave is faulty. We also connect the decrease of the apparent velocity over time with the phase mixing process, which depends on the curvature of the magnetic field lines. Methods: By measuring the displacement of the prominence at different heights to calculate the apparent velocity, we show that the propagation slows down over time, in accordance with the theoretical work of Kaneko et al. We also show that this propagation speed drops below what is to be expected for even slow MHD waves for those circumstances. We use a modified Kippenhahn-Schlüter prominence model to calculate the curvature of the magnetic field and fit our observations accordingly. Results: Measuring three of the apparent waves, we get apparent velocities of 14, 8, and 4 km s-1. Fitting a simple model for the magnetic field configuration, we obtain that the filament is located 103 Mm below the magnetic centre. We also obtain that the scale of the magnetic field strength in the vertical direction plays no role in the concept of apparent superslow waves and that the moment of excitation of the waves happened roughly one oscillation period before the end of the eruption that excited the oscillation. Conclusions: Some of the observed phase velocities are lower than expected for slow modes for the circumstances, showing that they rather fit with the concept of apparent superslow propagation. A fit with our magnetic field model allows for inferring the magnetic geometry of the prominence. The movie attached to Fig. 1 is available at http://www.aanda.org

Ion traps fabricated in a CMOS foundry

Energy Technology Data Exchange (ETDEWEB)

Mehta, K. K.; Ram, R. J. [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Eltony, A. M.; Chuang, I. L. [Center for Ultracold Atoms, Research Laboratory of Electronics and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Bruzewicz, C. D.; Sage, J. M., E-mail: jsage@ll.mit.edu; Chiaverini, J., E-mail: john.chiaverini@ll.mit.edu [Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, Massachusetts 02420 (United States)

2014-07-28

We demonstrate trapping in a surface-electrode ion trap fabricated in a 90-nm CMOS (complementary metal-oxide-semiconductor) foundry process utilizing the top metal layer of the process for the trap electrodes. The process includes doped active regions and metal interconnect layers, allowing for co-fabrication of standard CMOS circuitry as well as devices for optical control and measurement. With one of the interconnect layers defining a ground plane between the trap electrode layer and the p-type doped silicon substrate, ion loading is robust and trapping is stable. We measure a motional heating rate comparable to those seen in surface-electrode traps of similar size. This demonstration of scalable quantum computing hardware utilizing a commercial CMOS process opens the door to integration and co-fabrication of electronics and photonics for large-scale quantum processing in trapped-ion arrays.

Synthetic differential emission measure curves of prominence fine structures. II. The SoHO/SUMER prominence of 8 June 2004

Czech Academy of Sciences Publication Activity Database

Gunár, Stanislav; Parenti, S.; Anzer, U.; Heinzel, Petr; Vial, J. C.

2011-01-01

Roč. 535, November (2011), A122/1-A122/11 ISSN 0004-6361 R&D Projects: GA ČR GP205/09/P554; GA ČR GA205/09/1705; GA ČR GAP209/10/1706 Institutional research plan: CEZ:AV0Z10030501 Keywords : Sun * filaments * prominences Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.587, year: 2011

High Optical Access Trap 2.0.

Energy Technology Data Exchange (ETDEWEB)

Maunz, Peter Lukas Wilhelm [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-01-26

The High Optical Access (HOA) trap was designed in collaboration with the Modular Universal Scalable Ion-trap Quantum Computer (MUSIQC) team, funded along with Sandia National Laboratories through IARPA's Multi Qubit Coherent Operations (MQCO) program. The design of version 1 of the HOA trap was completed in September 2012 and initial devices were completed and packaged in February 2013. The second version of the High Optical Access Trap (HOA-2) was completed in September 2014 and is available at IARPA's disposal.

LARGE-SCALE FLOWS IN PROMINENCE CAVITIES

International Nuclear Information System (INIS)

Schmit, D. J.; Gibson, S. E.; Tomczyk, S.; Reeves, K. K.; Sterling, Alphonse C.; Brooks, D. H.; Williams, D. R.; Tripathi, D.

2009-01-01

Regions of rarefied density often form cavities above quiescent prominences. We observed two different cavities with the Coronal Multichannel Polarimeter on 2005 April 21 and with Hinode/EIS on 2008 November 8. Inside both of these cavities, we find coherent velocity structures based on spectral Doppler shifts. These flows have speeds of 5-10 km s -1 , occur over length scales of tens of megameters, and persist for at least 1 hr. Flows in cavities are an example of the nonstatic nature of quiescent structures in the solar atmosphere.

Laser trapping of 21Na atoms

International Nuclear Information System (INIS)

Lu, Zheng-Tian.

1994-09-01

This thesis describes an experiment in which about four thousand radioactive 21 Na (t l/2 = 22 sec) atoms were trapped in a magneto-optical trap with laser beams. Trapped 21 Na atoms can be used as a beta source in a precision measurement of the beta-asymmetry parameter of the decay of 21 Na → 21 Ne + Β + + v e , which is a promising way to search for an anomalous right-handed current coupling in charged weak interactions. Although the number o trapped atoms that we have achieved is still about two orders of magnitude lower than what is needed to conduct a measurement of the beta-asymmetry parameter at 1% of precision level, the result of this experiment proved the feasibility of trapping short-lived radioactive atoms. In this experiment, 21 Na atoms were produced by bombarding 24 Mg with protons of 25 MeV at the 88 in. Cyclotron of Lawrence Berkeley Laboratory. A few recently developed techniques of laser manipulation of neutral atoms were applied in this experiment. The 21 Na atoms emerging from a heated oven were first transversely cooled. As a result, the on-axis atomic beam intensity was increased by a factor of 16. The atoms in the beam were then slowed down from thermal speed by applying Zeeman-tuned slowing technique, and subsequently loaded into a magneto-optical trap at the end of the slowing path. The last two chapters of this thesis present two studies on the magneto-optical trap of sodium atoms. In particular, the mechanisms of magneto-optical traps at various laser frequencies and the collisional loss mechanisms of these traps were examined

Heat Conduction of Air in Nano Spacing

Directory of Open Access Journals (Sweden)

Zhang Yao-Zhong

2009-01-01

Full Text Available Abstract The scale effect of heat conduction of air in nano spacing (NS is very important for nanodevices to improve their life and efficiency. By constructing a special technique, the changes of heat conduction of air were studied by means of measuring the heat conduction with heat conduction instrument in NS between the hot plate and the cooling plate. Carbon nanotubes were used to produce the nano spacing. The results show that when the spacing is small down to nanometer scale, heat conduction plays a prominent role in NS. It was found that the thickness of air is a non-linear parameter for demarcating the heat conduction of air in NS and the rate of heat conduction in unit area could be regard as a typical parameter for the heat conduction characterization at nanometer scale.

Calibration of optically trapped nanotools

Energy Technology Data Exchange (ETDEWEB)

Carberry, D M; Simpson, S H; Grieve, J A; Hanna, S; Miles, M J [H H Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Wang, Y; Schaefer, H; Steinhart, M [Institute for Chemistry, University of Osnabrueck, Osnabrueck (Germany); Bowman, R; Gibson, G M; Padgett, M J, E-mail: m.j.miles@bristol.ac.uk [SUPA, Department of Physics and Astronomy, University of Glasgow, Science Road, Glasgow G12 8QQ (United Kingdom)

2010-04-30

Holographically trapped nanotools can be used in a novel form of force microscopy. By measuring the displacement of the tool in the optical traps, the contact force experienced by the probe can be inferred. In the following paper we experimentally demonstrate the calibration of such a device and show that its behaviour is independent of small changes in the relative position of the optical traps. Furthermore, we explore more general aspects of the thermal motion of the tool.

Diffusion to finite-size traps

International Nuclear Information System (INIS)

Richards, P.M.

1986-01-01

The survival probability of a random-walking particle is derived for hopping in a random distribution of traps of arbitrary radius and concentration. The single-center approximation is shown to be valid for times of physical interest even when the fraction of volume occupied by traps approaches unity. The theory is based on computation of the number of different potential trap regions sampled in a random walk and is confirmed by simulations on a simple-cubic lattice

Prominent crista terminalis mimicking a right atrial mass: case report

Directory of Open Access Journals (Sweden)

Lange Peter

2010-10-01

Full Text Available Abstract The crista terminalis is a normal anatomical structure within the right atrium that is not normally visualised in the standard views obtained while performing a transthoracic echocardiogram. In this case report, transthoracic echocardiography suggested the presence of a right atrial mass in a patient with end stage renal disease. However, subsequent transesophageal echocardiography revealed that the right atrial mass was actually a thick muscular bridge in the right atrium consistent with a prominent crista terminalis. An understanding of the anatomy and the echocardiographic appearance of a prominent crista terminalis will minimize the misdiagnosis of this structure avoiding unnecessary expensive additional tests.

RNA-Seq reveals the molecular mechanism of trapping and killing of root-knot nematodes by nematode-trapping fungi.

Science.gov (United States)

Pandit, Ramesh; Patel, Reena; Patel, Namrata; Bhatt, Vaibhav; Joshi, Chaitanya; Singh, Pawan Kumar; Kunjadia, Anju

2017-04-01

Nematode-trapping fungi are well known for their inherent potential to trap and kill nematodes using specialized trapping devices. However, the molecular mechanisms underlying the trapping and subsequent processes are still unclear. Therefore, in this study, we examined differential genes expression in two nematode-trapping fungi after baiting with nematode extracts. In Arthrobotrys conoides, 809 transcripts associated with diverse functions such as signal transduction, morphogenesis, stress response and peroxisomal proteins, proteases, chitinases and genes involved in the host-pathogen interaction showed differential expression with fold change (>±1.5 fold) in the presence of nematode extract with FDR (p-value nematode-trapping fungi for its host. The findings illustrate the molecular mechanism of fungal parasitism in A. conoides which may be helpful in developing a potential biocontrol agent against parasitic nematodes.

The Fate of Cool Material in the Hot Corona: Solar Prominences and Coronal Rain

Science.gov (United States)

Liu, Wei; Antolin, Patrick; Sun, Xudong; Vial, Jean-Claude; Berger, Thomas

2017-08-01

As an important chain of the chromosphere-corona mass cycle, some of the million-degree hot coronal mass undergoes a radiative cooling instability and condenses into material at chromospheric or transition-region temperatures in two distinct forms - prominences and coronal rain (some of which eventually falls back to the chromosphere). A quiescent prominence usually consists of numerous long-lasting, filamentary downflow threads, while coronal rain consists of transient mass blobs falling at comparably higher speeds along well-defined paths. It remains puzzling why such material of similar temperatures exhibit contrasting morphologies and behaviors. We report recent SDO/AIA and IRIS observations that suggest different magnetic environments being responsible for such distinctions. Specifically, in a hybrid prominence-coronal rain complex structure, we found that the prominence material is formed and resides near magnetic null points that favor the radiative cooling process and provide possibly a high plasma-beta environment suitable for the existence of meandering prominence threads. As the cool material descends, it turns into coronal rain tied onto low-lying coronal loops in a likely low-beta environment. Such structures resemble to certain extent the so-called coronal spiders or cloud prominences, but the observations reported here provide critical new insights. We will discuss the broad physical implications of these observations for fundamental questions, such as coronal heating and beyond (e.g., in astrophysical and/or laboratory plasma environments).

Study of the irreversible trapping of dihydrogen with the use of a MnO2/Ag2O mixture

International Nuclear Information System (INIS)

Galliez, K.

2012-01-01

The hydrogen risk generated by radiolysis of organic compounds during a nuclear waste transport is a major issue. The use of irreversible getters is considered to limit this risk. The aim of this work is to study one of these getters, MnO 2 /Ag 2 O, in order to better understand the trapping phenomenon and to ensure its reliability. Initially several parameters affecting the trapping kinetics were studied. It has been shown that among all MnO 2 allotropic phases, the nsutite has the best trapping kinetics. Moreover, specific surface area and defect amount in MnO 2 can enhance trapping performances. Ag 2 O weight percentage (acting as promotor) has been determined at 13% to have the best trapping kinetics. Chemisorption of H 2 , which is required for its application, has been shown by using several characterization techniques such as magnetometry, infrared spectroscopy and electronic energy loss spectroscopy. The trapping irreversibility and the regeneration of the getter have been demonstrated respectively under nitrogen or air at 150 C. Finally, proton insertion mechanism in MnO 2 has been elucidated by pairs distribution function analysis through the development of a model to simulate the complex structure of MnO 2 . It has been shown that Ag 2 O is turned into Ag 2 CO 3 during the preparation of the getter under water, which has never been demonstrated. (author) [fr

The Electronic McPhail Trap

Directory of Open Access Journals (Sweden)

Ilyas Potamitis

2014-11-01

Full Text Available Certain insects affect cultivations in a detrimental way. A notable case is the olive fruit fly (Bactrocera oleae (Rossi, that in Europe alone causes billions of euros in crop-loss/per year. Pests can be controlled with aerial and ground bait pesticide sprays, the efficiency of which depends on knowing the time and location of insect infestations as early as possible. The inspection of traps is currently carried out manually. Automatic monitoring traps can enhance efficient monitoring of flying pests by identifying and counting targeted pests as they enter the trap. This work deals with the hardware setup of an insect trap with an embedded optoelectronic sensor that automatically records insects as they fly in the trap. The sensor responsible for detecting the insect is an array of phototransistors receiving light from an infrared LED. The wing-beat recording is based on the interruption of the emitted light due to the partial occlusion from insect’s wings as they fly in the trap. We show that the recordings are of high quality paving the way for automatic recognition and transmission of insect detections from the field to a smartphone. This work emphasizes the hardware implementation of the sensor and the detection/counting module giving all necessary implementation details needed to construct it.

Laser trapping of radioactive francium atoms

International Nuclear Information System (INIS)

Sprouse, G.D.; Orozco, L.A.; Simsarian, J.E.; Shi, W.; Zhao, W.Z.

1997-01-01

The difficult problem of quickly slowing and cooling nuclear reaction products so that they can be injected into a laser trap has been solved by several groups and there are now strong efforts to work with the trapped atoms. The atoms are confined in the trap to a small spatial volume of the order of 1 mm 3 , but more importantly, they are also confined in velocity, which makes them an ideal sample for spectroscopic measurements with other lasers. We have recently trapped radioactive francium and have embarked on a program to further study the francium atom as a prelude to a test of the Standard Model analogous to previous work with Cs. Our sample of 3 min 210 Fr now contains over 20 000 atoms, and is readily visible with an ordinary TV camera. We work on-line with the accelerator, and continuously load the trap to replace losses due to decay and collisions with background gas. We have maintained a sample of Fr atoms in the trap for over 10 hours, with occasional adjustment of the trapping laser frequency to account for drifts. The proposed test of the Standard Model will require accurate calculation of its atomic properties. We are currently testing these calculations by measuring other predicted quantities. (orig.)

Positron-trapping mechanism at dislocations in Zn

DEFF Research Database (Denmark)

Hidalgo, Carlos; Linderoth, Søren; Diego, Nieves de

1987-01-01

the average lifetime and the intensity of the long component decrease with increasing temperature. The experimental results are very well described in terms of a generalized trapping model where it is assumed that positrons become trapped in deep traps (jogs) via shallow traps (dislocation lines......). The temperature dependence of the positron-lifetime spectra below 120 K is attributed to the temperature dependence of the trapping rate to the dislocation line. The experimental results have demonstrated that detrapping processes from the dislocation line take place above 120 K. The positron binding energy...

Optimization and simulation of MEMS rectilinear ion trap

Directory of Open Access Journals (Sweden)

Huang Gang

2015-04-01

Full Text Available In this paper, the design of a MEMS rectilinear ion trap was optimized under simulated conditions. The size range of the MEMS rectilinear ion trap’s electrodes studied in this paper is measured at micron scale. SIMION software was used to simulate the MEMS rectilinear ion trap with different sizes and different radio-frequency signals. The ion-trapping efficiencies of the ion trap under these different simulation conditions were obtained. The ion-trapping efficiencies were compared to determine the performance of the MEMS rectilinear ion trap in different conditions and to find the optimum conditions. The simulation results show that for the ion trap at micron scale or smaller, the optimized length–width ratio was 0.8, and a higher frequency of radio-frequency signal is necessary to obtain a higher ion-trapping efficiency. These results have a guiding role in the process of developing MEMS rectilinear ion traps, and great application prospects in the research fields of the MEMS rectilinear ion trap and the MEMS mass spectrometer.

Stability of trapped electrons in SiO2

International Nuclear Information System (INIS)

Fleetwood, D.M.; Winokur, P.S.; Flament, O.; Leray, J.L.

1998-01-01

Electron trapping near the Si/SiO 2 interface plays a crucial role in mitigating the response of MOS devices to ionizing radiation or high-field stress. These electrons offset positive charge due to trapped holes, and can be present at densities exceeding 10 12 cm -2 in the presence of a similar density of trapped positive charge. The nature of the defects that serve as hosts for trapped electrons in the near-interfacial SiO 2 is presently unknown, although there is compelling evidence that these defects are often intimately associated with trapped holes. This association is depicted most directly in the model of Lelis et al., which suggests that trapped electrons and holes occupy opposite sides of a compensated E center in SiO 2 . Charge exchange between electron traps and the Si can occur over a wide range of time scales, depending on the trap depth and location relative to the Si/SiO 2 interface. Here the authors report a detailed study of the stability of electron traps associated with trapped holes near the Si/SiO 2 interface

The Aarhus Ion Micro-Trap Project

DEFF Research Database (Denmark)

Miroshnychenko, Yevhen; Nielsen, Otto; Poulsen, Gregers

As part of our involvement in the EU MICROTRAP project, we have designed, manufactured and assembled a micro-scale ion trap with integrated optical fibers. These prealigned fibers will allow delivering cooling laser light to single ions. Therefore, such a trap will not require any direct optical...... and installed in an ultra high vacuum chamber, which includes an ablation oven for all-optical loading of the trap [2]. The next steps on the project are to demonstrate the operation of the micro-trap and the cooling of ions using fiber delivered light. [1] D. Grant, Development of Micro-Scale Ion traps, Master...... Thesis (2008). [2] R.J. Hendricks, D.M. Grant, P.F. Herskind, A. Dantan and M. Drewsen, An all-optical ion-loading technique for scalable microtrap architectures, Applied Physics B, 88, 507 (2007)....

Whole genome microarray analysis of chicken embryo facial prominences

Czech Academy of Sciences Publication Activity Database

Buchtová, Marcela; Kuo, W. P.; Nimmagadda, S.; Benson, S. L.; Geetha-Loganathan, P.; Logan, C.; Au-Yeung, T.; Chiang, E.; Fu, K.; Richman, J. M.

2010-01-01

Roč. 239, - (2010), s. 574-591 ISSN 1058-8388 Institutional research plan: CEZ:AV0Z50450515 Keywords : pharyngeal arch * mandibular arch * maxillary prominence Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.864, year: 2010

The Most Prominent Roles of an ESP Teacher

Science.gov (United States)

Ghafournia, Narjes; Sabet, Shokoofeh Ahmadian

2014-01-01

One prominent feature of many ESP (English for Specific Purposes) courses, which make them rather different from EGP (English for General Purposes) courses, is the presence of adult learners, who are primary workers and secondary learners. As ESP is a highly learner-cantered approach, paying close attention to the multidimensional needs of…

Further Validation of the Coach Identity Prominence Scale

Science.gov (United States)

Pope, J. Paige; Hall, Craig R.

2014-01-01

This study was designed to examine select psychometric properties of the Coach Identity Prominence Scale (CIPS), including the reliability, factorial validity, convergent validity, discriminant validity, and predictive validity. Coaches (N = 338) who averaged 37 (SD = 12.27) years of age, had a mean of 13 (SD = 9.90) years of coaching experience,…

SOLAR LIMB PROMINENCE CATCHER AND TRACKER (SLIPCAT): AN AUTOMATED SYSTEM AND ITS PRELIMINARY STATISTICAL RESULTS

International Nuclear Information System (INIS)

Wang Yuming; Cao Hao; Chen Junhong; Zhang Tengfei; Yu Sijie; Zheng Huinan; Shen Chenglong; Wang, S.; Zhang Jie

2010-01-01

In this paper, we present an automated system, which has the capability to catch and track solar limb prominences based on observations from the extreme-ultraviolet (EUV) 304 A passband. The characteristic parameters and their evolution, including height, position angle, area, length, and brightness, are obtained without manual interventions. By applying the system to the STEREO-B/SECCHI/EUVI 304 A data during 2007 April-2009 October, we obtain a total of 9477 well-tracked prominences and a catalog of these events available online. A detailed analysis of these prominences suggests that the system has a rather good performance. We have obtained several interesting statistical results based on the catalog. Most prominences appear below the latitude of 60 0 and at the height of about 26 Mm above the solar surface. Most of them are quite stable during the period they are tracked. Nevertheless, some prominences have an upward speed of more than 100 km s -1 , and some others show significant downward and/or azimuthal speeds. There are strong correlations among the brightness, area, and height. The expansion of a prominence is probably one major cause of its fading during the rising or erupting process.

Sognenavne, Lemvig Kommune (18 artikler). trap.dk

DEFF Research Database (Denmark)

Kællerød, Lars-Jakob Harding

2017-01-01

Artikler til Trap Danmarks netpublikation trap.dk Sognenavnene Bøvling, Dybe, Engbjerg, Fabjerg, Ferring, Fjaltring, Flynder, Gudum, Heldum, Hygum, Lomborg, Møborg, Nees, Nørlem, Rom, Trans, Tørring og Vandborg......Artikler til Trap Danmarks netpublikation trap.dk Sognenavnene Bøvling, Dybe, Engbjerg, Fabjerg, Ferring, Fjaltring, Flynder, Gudum, Heldum, Hygum, Lomborg, Møborg, Nees, Nørlem, Rom, Trans, Tørring og Vandborg...

A search for mixotrophy and mucus trap production in Alexandrium spp. and the dynamics of mucus trap formation in Alexandrium pseudogonyaulax

DEFF Research Database (Denmark)

Blossom, Hannah Eva; Bædkel, Tina Dencker; Tillmann, Urban

2017-01-01

, such as speed and frequency of trap formation as well as what happens to the trap after the A. pseudogonyaulax cell detaches from it. The percentage of A. pseudogonyaulax cells producing a mucus trap and the number of prey cells caught increased with increasing prey concentration, whereas the physical size...... of the traps was independent of prey concentration. In one strain given an excess of prey, within 1 h over 90% of individual A. pseudogonyaulax cells had formed a trap, each containing an average of 45 prey cells. Individual A. pseudogonyaulax cells steadily produced traps and up to 5 traps were produced...

Towards a Quantum Interface between Diamond Spin Qubits and Phonons in an Optical Trap

Science.gov (United States)

Ji, Peng; Momeen, M. Ummal; Hsu, Jen-Feng; D'Urso, Brian; Dutt, Gurudev

2014-05-01

We introduce a method to optically levitate a pre-selected nanodiamond crystal in air or vacuum. The nanodiamond containing nitrogen-vacancy (NV) centers is suspended on a monolayer of graphene transferred onto a patterned substrate. Laser light is focused onto the sample, using a home-built confocal microscope with a high numerical aperture (NA = 0.9) objective, simultaneously burning the graphene and creating a 3D optical trap that captures the falling nano-diamond at the beam waist. The trapped diamond is an ultra-high-Q mechanical oscillator, allowing us to engineer strong linear and quadratic coupling between the spin of the NV center and the phonon mode. The system could result in an ideal quantum interface between a spin qubit and vibrational phonon mode, potentially enabling applications in quantum information processing and sensing the development of quantum information storage and processing.

Charged particle traps II applications

CERN Document Server

Werth, Günther; Major, Fouad G

2009-01-01

This, the second volume of Charged Particle Traps, is devoted to applications, complementing the first volume’s comprehensive treatment of the theory and practice of charged particle traps, their many variants and refinements. In recent years, applications of far reaching importance have emerged ranging from the ultra-precise mass determinations of elementary particles and their antiparticles and short-lived isotopes, to high-resolution Zeeman spectroscopy on multiply-charged ions, to microwave and optical spectroscopy, some involving "forbidden" transitions from metastable states of such high resolution that optical frequency standards are realized by locking lasers to them. Further the potential application of trapped ions to quantum computing is explored, based on the extraordinary quantum state coherence made possible by the particle isolation. Consideration is given to the Paul and Penning traps as potential quantum information processors.

Hydrogen line formation in the quescent prominences

International Nuclear Information System (INIS)

Tsovookhuu, Ch.

1980-01-01

Equations of transfer and statistical equilibrium for hydronen atom with eight bound levels and continuum are solved simultaneously. A plane-parallel layer located perpendicular to the Sun surface is taken as a geometrical model. Input parameters of the physical model are optical thickness in the center of Hsub(α) line, electron temperature and concentration in the layer center are well as temperature and density gradients. Functions of sources, line profiles, total energies and the Balmer decrements, which are compared with observations and theoretical calculations made by other authors, have been calculated. The comparison shows that the results are quite acceptable and can be used when analyzing the spectrum and determining physical parameters of solar prominences. Dependence of different performances of the line (equivalent width, central intensity, halfwidth, depth of central depression etc.) on values of initial model parameters is investigated. Line halfwidth is more sensitive to the temperatuu value in the layer center, while central intensity - to the value of temperature gradient and a depth of central depression - to electron concentration. Calculated were shares of primary sources responsible for different excitation mechanism depending on total optical thickness as well as mean probabilities of quantum yield out of a medium which can be used during parametric accountancy of radiation diffusion in solar prominences [ru

Air radioactivity: to assess risks. Tools answer citizen questions. The Opera-Air network: the journey of a filter

International Nuclear Information System (INIS)

Didier, Damien; Gariel, Jean-Christophe; Bruno, Valerie; Debayle, Christophe

2017-01-01

Very highly efficient filters containing a porous glass fibre fabric are used in industrial installations to trap radioactive or toxic particles in order to limit their release, notably in accidental situations. Thus this set of articles discusses various issues related to the use of such filters. A first one describes how air radioactivity is continuously monitored by two coexisting networks: Opera-Air and Teleray. It indicates where air radioactivity comes from, and how the origin of a release can be determined, and outlines the importance of modelling tools. Air monitoring about the Gravelines nuclear power plant is briefly presented with a drawing. A second article comments the existence of numerous tools which are used as information channels about the monitoring of air radioactivity: web sites, mobile application, and so on. The last article briefly describes the journey of a filter from its removal on a Monday to a complete and validated analysis which lasts between two and four weeks

Trap-induced photoconductivity in singlet fission pentacene diodes

Energy Technology Data Exchange (ETDEWEB)

Qiao, Xianfeng, E-mail: qiaoxianfeng@hotmail.com; Zhao, Chen; Chen, Bingbing; Luan, Lin [WuHan National Laboratory for Optoelectronics and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wu Han 430074 (China)

2014-07-21

This paper reports a trap-induced photoconductivity in ITO/pentacene/Al diodes by using current-voltage and magneto-conductance measurements. The comparison of photoconductivity between pentacene diodes with and without trap clearly shows that the traps play a critical role in generating photoconductivity. It shows that no observable photoconductivity is detected for trap-free pentacene diodes, while significant photoconductivity is observed in diodes with trap. This is because the initial photogenerated singlet excitons in pentacene can rapidly split into triplet excitons with higher binding energy prior to dissociating into free charge carriers. The generated triplet excitons react with trapped charges to release charge-carriers from traps, leading to a trap-induced photoconductivity in the single-layer pentacene diodes. Our studies elucidated the formation mechanisms of photoconductivity in pentacene diodes with extremely fast singlet fission rate.

Trapping molecules in two and three dimensions

International Nuclear Information System (INIS)

Pinkse, PW.H.; Junglen, T.; Rieger, T.; Rangwala, S.A.; Windpassinger, P.; Rempe, G.

2005-01-01

Full text: Cold molecules offer a new testing ground for quantum-physical effects in nature. For example, producing slow beams of large molecules could push experiments studying the boundary between quantum interference and classical particles up towards ever heavier particles. Moreover, cold molecules, in particular YbF, seem an attractive way to narrow down the constraints on the value of the electron dipole moment and finally, quantum information processing using chains of cold polar molecules or vibrational states in molecules have been proposed. All these proposals rely on advanced production and trapping techniques, most of which are still under development. Therefore, novel production and trapping techniques for cold molecules could offer new possibilities not found in previous methods. Electric traps hold promise for deep trap potentials for neutral molecules. Recently we have demonstrated two-dimensional trapping of polar molecules in a four-wire guide using electrostatic and electrodynamic trapping techniques. Filled from a thermal effusive source, such a guide will deliver a beam of slow molecules, which is an ideal source for interferometry experiments with large molecules, for instance. Here we report about the extension of this work to three-dimensional trapping. Polar molecules with a positive Stark shift can be trapped in the minimum of an electrostatic field. We have successfully tested a large volume electrostatic trap for ND3 molecules. A special feature of this trap is that it can be loaded continuously from an electrostatic guide, at a temperature of a few hundred mK. (author)

SYNTHETIC HYDROGEN SPECTRA OF OSCILLATING PROMINENCE SLABS IMMERSED IN THE SOLAR CORONA

International Nuclear Information System (INIS)

Zapiór, M.; Heinzel, P.; Oliver, R.; Ballester, J. L.

2016-01-01

We study the behavior of H α and H β spectral lines and their spectral indicators in an oscillating solar prominence slab surrounded by the solar corona, using an MHD model combined with a 1D radiative transfer code taken in the line of sight perpendicular to the slab. We calculate the time variation of the Doppler shift, half-width, and maximum intensity of the H α and H β spectral lines for different modes of oscillation. We find a non-sinusoidal time dependence of some spectral parameters with time. Because H α and H β spectral indicators have different behavior for different modes, caused by differing optical depths of formation and different plasma parameter variations in time and along the slab, they may be used for prominence seismology, especially to derive the internal velocity field in prominences.

SYNTHETIC HYDROGEN SPECTRA OF OSCILLATING PROMINENCE SLABS IMMERSED IN THE SOLAR CORONA

Energy Technology Data Exchange (ETDEWEB)

Zapiór, M.; Heinzel, P. [Astronomical Institute, The Czech Academy of Sciences, 25165 Ondřejov, The Czech Republic (Czech Republic); Oliver, R.; Ballester, J. L. [Universitat de les Illes Balears. Cra. de Valldemossa, km 7.5. Palma (Illes Balears), E-07122 (Spain)

2016-08-20

We study the behavior of H α and H β spectral lines and their spectral indicators in an oscillating solar prominence slab surrounded by the solar corona, using an MHD model combined with a 1D radiative transfer code taken in the line of sight perpendicular to the slab. We calculate the time variation of the Doppler shift, half-width, and maximum intensity of the H α and H β spectral lines for different modes of oscillation. We find a non-sinusoidal time dependence of some spectral parameters with time. Because H α and H β spectral indicators have different behavior for different modes, caused by differing optical depths of formation and different plasma parameter variations in time and along the slab, they may be used for prominence seismology, especially to derive the internal velocity field in prominences.

Antimatter Plasmas in a Multipole Trap for Antihydrogen

CERN Document Server

Andresen, G B; Boston, A; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Chartier, M; Deutsch, A; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Gomberoff, K; Hangst, J S; Hayano, R S; Hydomako, R; Jenkins, M J; Jørgensen, L V; Kurchaninov, L; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Robicheaux, F; Sarid, E; Silveira, D M; Storey, J W; Telle, H H; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

2007-01-01

We have demonstrated storage of plasmas of the charged constituents of the antihydrogen atom, antiprotons and positrons, in a Penning trap surrounded by a minimum-B magnetic trap designed for holding neutral antiatoms. The neutral trap comprises a superconducting octupole and two superconducting, solenoidal mirror coils. We have measured the storage lifetimes of antiproton and positron plasmas in the combined Penning-neutral trap, and compared these to lifetimes without the neutral trap fields. The magnetic well depth was 0.6 T, deep enough to trap ground state antihydrogen atoms of up to about 0.4 K in temperature. We have demonstrated that both particle species can be stored for times long enough to permit antihydrogen production and trapping studies.

Antimatter plasmas in a multipole trap for antihydrogen.

Science.gov (United States)

Andresen, G; Bertsche, W; Boston, A; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Chartier, M; Deutsch, A; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Gomberoff, K; Hangst, J S; Hayano, R S; Hydomako, R; Jenkins, M J; Jørgensen, L V; Kurchaninov, L; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Robicheaux, F; Sarid, E; Silveira, D M; Storey, J W; Telle, H H; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

2007-01-12

We have demonstrated storage of plasmas of the charged constituents of the antihydrogen atom, antiprotons and positrons, in a Penning trap surrounded by a minimum-B magnetic trap designed for holding neutral antiatoms. The neutral trap comprises a superconducting octupole and two superconducting, solenoidal mirror coils. We have measured the storage lifetimes of antiproton and positron plasmas in the combined Penning-neutral trap, and compared these to lifetimes without the neutral trap fields. The magnetic well depth was 0.6 T, deep enough to trap ground state antihydrogen atoms of up to about 0.4 K in temperature. We have demonstrated that both particle species can be stored for times long enough to permit antihydrogen production and trapping studies.

Experimental pseudo-symmetric trap EPSILON

International Nuclear Information System (INIS)

Skovoroda, A.A.; Arsenin, V.V.; Dlougach, E.D.; Kulygin, V.M.; Kuyanov, A.Yu.; Timofeev, A.V.; Zhil'tsov, V.A.; Zvonkov, A.V.

2001-01-01

Within the framework of the conceptual project 'Adaptive Plasma EXperiment' a trap with the closed magnetic field lines 'Experimental Pseudo-Symmetric trap' is examined. The project APEX is directed at the theoretical and experimental development of physical foundations for stationary thermonuclear reactor on the basis of an alternative magnetic trap with tokamak-level confinement of high β plasma. The fundamental principle of magnetic field pseudosymmetry that should be satisfied for plasma to have tokamak-like confinement is discussed. The calculated in paraxial approximation examples of pseudosymmetric curvilinear elements with poloidal direction of B isolines are adduced. The EPSILON trap consisting of two straight axisymmetric mirrors linked by two curvilinear pseudosymmetric elements is considered. The plasma currents are short-circuited within the curvilinear element what increases the equilibrium β. The untraditional scheme of MHD stabilization of a trap with the closed field lines by the use of divertor inserted into axisymmetric mirror is analyzed. The experimental installation EPSILON-OME that is under construction for experimental check of divertor stabilization is discussed. The possibility of ECR plasma production in EPSILON-OME under conditions of high density and small magnetic field is examined. (author)

A Rotating-Bears Optical Dipole Trap for Cold Aatoms

International Nuclear Information System (INIS)

Friedman, N.; Ozeri, R.; Khaykovich, L.; Davidson, N.

1999-01-01

In the last few years, several optical dipole traps for cold atoms were demonstrated and used to study cold atomic collisions, long atomic coherence times and quantum collective effects. Blue-detuned dipole traps, where repulsive light forces confines atoms mostly in dark, offer long storage, and photon-scattering times, combined with strong confinement forces. Unfortunately, such blue-detuned dipole traps involve complicated light intensity distributions that require either multiple laser beams or complicated phase elements. Here, we propose and demonstrate a novel configuration for a single-beam blue-detuned dipole trap, which enables larger trapping volume, and fast temporal changes in the trap size and shape. Our trap consists of a tightly-focused laser beam which is rapidly rotated (with rotation frequency up to 400 khz) with two orthogonal acousto optical scanners. For very high rotation frequencies the atoms feel a time-averaged static dipole potential. Therefore, when the radius of rotation is larger than the beam size, a dark volume which is completely surrounded by light is obtained around the focal region. By changing the rotation radius and the trapping laser intensity and detuning, the trap dimensions and oscillation frequency could be changed over a large parameter range. In particular trap diameters were changed between 50 to 220 microns and trap length was changed between 3.5 to 16 mm. ∼10 6 atoms were loaded into the rotating-beam dipole trap from a magneto optical trap. The density of the trapped atoms was 4x10 10 atoms/cm 3 ,their temperature was -6 pK. and the trap (1/e) lifetime was 0.65 sec, limited by collisions with background atoms. When the rotation frequency was decreased below the oscillation frequency of the atoms in the trap, the trap became unstable, and a sharp reduction of the trap lifetime was observed, in agreement with our theoretical analysis. Finally, we demonstrated adiabatic compression of atoms in the trap by decreasing

Performance and regeneration of a pellet-packed-bed diesel-particulate trap; Ryutai jutenso diesel biryushi trap no seino oyobi saisei

Energy Technology Data Exchange (ETDEWEB)

Shioji, M; Nakai, S; Ikegami, M [Kyoto University, Kyoto (Japan); Hori, Y [Yamaha Motor Co. Ltd., Shizuoka (Japan)

1997-10-01

This paper demonstrates with the feasibility of a pellet-packed bed for trapping diesel particulates. After making pellets loose from the packed condition, regeneration is established by a circulation of pellets in the trap and collected particulates are efficiently dropped out through the wire mesh on the bottom of the trap. An experimental trap with the pellet-circulation system using a spiral feeder is tested on a single-cylinder test engine to show the trap and regeneration efficiencies. In addition, the condition of pellet circulation is observed using the transparent cylinder, based on which the design of pellet and trap sizes are discussed. 6 refs., 10 figs.

Sognenavne, Aabenraa Kommune (16 artikler). trap.dk

DEFF Research Database (Denmark)

Kællerød, Lars-Jakob Harding

2019-01-01

Artikler til Trap Danmarks netpublikation trap.dk Sognenavnene Bjolderup, Burkal, Bylderup, Egvad, Ensted, Genner, Hellevad, Hjordkær, Holbøl, Kliplev, Løjt, Ravsted, Rise, Uge, Varnæs og Øster Løgum......Artikler til Trap Danmarks netpublikation trap.dk Sognenavnene Bjolderup, Burkal, Bylderup, Egvad, Ensted, Genner, Hellevad, Hjordkær, Holbøl, Kliplev, Løjt, Ravsted, Rise, Uge, Varnæs og Øster Løgum...

Determination of tellurium by hydride generation with in situ trapping flame atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Matusiewicz, H.; Krawczyk, M. [Politechn Poznanska, Poznan (Poland)

2007-03-15

The analytical performance of coupled hydride generation - integrated atom trap (HG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system was evaluated for determination of Te in reference material (GBW 07302 Stream Sediment), coal fly ash and garlic. Tellurium, using formation of H{sub 2}Te vapors, is atomized in air-acetylene flame-heated IAT. A new design HG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangernents (a water-cooled single silica tube, double-slotted quartz tube or an 'integrated trap') was investigated. An improvement in detection limit was achieved compared with using either of the above atom trapping techniques separately. The concentration detection limit, defined as 3 times the blank standard deviation (3{sigma}), was 0.9 ng mL{sup -1} for Te. For a 2 min in situ preconcentration time (sample volume of 2 mL), sensitivity enhancement compared to flame AAS, was 222 fold, using the hydride generation atom trapping technique. The sensitivity can be further improved by increasing the collection time. The precision, expressed as RSD, was 7.0% (n = 6) for Te. The accuracy of the method was verified using a certified reference material (GBW 07302 Stream Sediment) by aqueous standard calibration curves. The measured Te contents of the reference material was in agreement with the information value. The method was successfully applied to the determination of tellurium in coal fly ash and garlic.

Antioxidant pool in beer and kinetics of EPR spin-trapping.

Science.gov (United States)

Kocherginsky, Nikolai M; Kostetski, Yuri Yu; Smirnov, Alex I

2005-08-24

The kinetics of spin-trap adduct formation in beer oxidation exhibits an induction period if the reaction is carried out at elevated temperatures and in the presence of air. This lag period lasts until the endogenous antioxidants are almost completely depleted, and its duration is used as an indicator of the flavor stability and shelf life of beer. This paper demonstrates that the total kinetics of the process can be characterized by three parameters-the lag period, the rate of spin-trap adduct formation, and, finally, the steady-state spin-adduct concentration. A steady-state chain reaction mechanism is described, and quantitative estimates of the main kinetic parameters such as the initiation rate, antioxidant pool, effective content of organic molecules participating in the chain reactions, and the rate constant of the 1-hydroxyethyl radical EtOH(*) spin-adduct disappearance are given. An additional new dimensionless parameter is suggested to characterize the antioxidant pool-the product of the lag time and the rate of spin-trap radical formation immediately after the lag time, normalized by the steady-state concentration of the adducts. The results of spin-tapping EPR experiments are compared with the nitroxide reduction kinetics measured in the same beer samples. It is shown that although the kinetics of nitroxide reduction in beer can be used to evaluate the reducing power of beer, the latter parameter does not correlate with the antioxidant pool. The relationship of free radical processes, antioxidant pool, reducing power, and beer staling is discussed.

Deuterium trapping in carbon fiber composites under high fluence

International Nuclear Information System (INIS)

Airapetov, A.A.; Begrambekov, L.B.; Kuzmin, A.A.; Shigin, P.A.; Zakharov, A.M.

2010-01-01

The paper is devoted to investigation of deuterium trapping in CFC, dance graphite MPG-8 and pyrolytic graphite (PG) under plasma ion- and electron irradiation. Number of specific features of deuterium trapping and retention under plasma ion and electron irradiation is presented and discussed. In particular it is shown that 1) deuterium trapping takes place even when energy of impinging ions approaches zero; 2) deuterium is trapped under irradiation by plasma electrons; 3) under irradiation at equal fluences deuterium trapping is higher, when ion flux is smaller. High energy ion penetrating the surfaces are trapped in the traps created at the expense of their kinetic energy. The process may be named 'kinetic trapping'. Under low energy (smaller than 200 eV) electron and/or ion irradiation the energy of inelastic interaction on the surface provides creation of active centers, which initiate dissociation of deuterium sorbed on the surface, penetration of deuterium atoms into graphite and their trapping in specific low energy traps. The term 'potential trapping' is proposed for this type of trapping. Under high energy irradiation such atoms can fill the traps formed through kinetic mechanism. Origination of moveable deuterium atoms from the layer of surface sorption seems to be time dependent process and it is a reason of increase of trapping along with irradiation time. New features of deuterium trapping and retention in graphite evaluated in this study offer new opportunities for analysis and correct estimation of hydrogen isotope trapping and retention in tokamaks having graphite tiles. (authors)

The historical dynamics of social-ecological traps.

Science.gov (United States)

Boonstra, Wiebren J; de Boer, Florianne W

2014-04-01

Environmental degradation is a typical unintended outcome of collective human behavior. Hardin's metaphor of the "tragedy of the commons" has become a conceived wisdom that captures the social dynamics leading to environmental degradation. Recently, "traps" has gained currency as an alternative concept to explain the rigidity of social and ecological processes that produce environmental degradation and livelihood impoverishment. The trap metaphor is, however, a great deal more complex compared to Hardin's insight. This paper takes stock of studies using the trap metaphor. It argues that the concept includes time and history in the analysis, but only as background conditions and not as a factor of causality. From a historical-sociological perspective this is remarkable since social-ecological traps are clearly path-dependent processes, which are causally produced through a conjunction of events. To prove this point the paper conceptualizes social-ecological traps as a process instead of a condition, and systematically compares history and timing in one classic and three recent studies of social-ecological traps. Based on this comparison it concludes that conjunction of social and environmental events contributes profoundly to the production of trap processes. The paper further discusses the implications of this conclusion for policy intervention and outlines how future research might generalize insights from historical-sociological studies of traps.

Asymmetric ion trap

Science.gov (United States)

Barlow, Stephan E.; Alexander, Michael L.; Follansbee, James C.

1997-01-01

An ion trap having two end cap electrodes disposed asymmetrically about a center of a ring electrode. The inner surface of the end cap electrodes are conformed to an asymmetric pair of equipotential lines of the harmonic formed by the application of voltages to the electrodes. The asymmetry of the end cap electrodes allows ejection of charged species through the closer of the two electrodes which in turn allows for simultaneously detecting anions and cations expelled from the ion trap through the use of two detectors charged with opposite polarity.

Developing optical traps for ultra-sensitive analysis

International Nuclear Information System (INIS)

Zhao, X.; Vieira, D.J.; Guckert, R.; Crane, S.

1998-01-01

The authors describe the coupling of a magneto-optical trap to a mass separator for the ultra-sensitive detection of selected radioactive species. As a proof of principle test, they have demonstrated the trapping of ∼ 6 million 82 Rb (t 1/2 = 75 s) atoms using an ion implantation and heated foil release method for introducing the sample into a trapping cell with minimal gas loading. Gamma-ray counting techniques were used to determine the efficiencies of each step in the process. By far the weakest step in the process is the efficiency of the optical trap itself (0.3%). Further improvements in the quality of the nonstick dryfilm coating on the inside of the trapping cell and the possible use of larger diameter laser beams are indicated. In the presence of a large background of scattered light, this initial work achieved a detection sensitivity of ∼ 4,000 trapped atoms. Improved detection schemes using a pulsed trap and gated photon detection method are outlined. Application of this technology to the areas of environmental monitoring and nuclear proliferation are foreseen

Improving detection tools for emerald ash borer (Coleoptera: Buprestidae): comparison of multifunnel traps, prism traps, and lure types at varying population densities.

Science.gov (United States)

Crook, Damon J; Francese, Joseph A; Rietz, Michael L; Lance, David R; Hull-Sanders, Helen M; Mastro, Victor C; Silk, Peter J; Ryall, Krista L

2014-08-01

The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is a serious invasive pest of North American ash (Fraxinus spp.) that has caused devastating mortality since it was first identified in North America in 2002. In 2012, we conducted field trapping assays that tested the efficacy of purple prism and fluon-coated green multifunnel (Lindgren funnel) traps. Traps were baited with combinations of several lures that were previously shown to be attractive to A. planipennis: manuka oil--a sesquiterpene-rich oil, (3Z)-hexenol--a green leaf volatile, or (3Z)-dodecen-12-olide [= (3Z)-lactone], a sex pheromone. Eighty-nine blocks (trap lines) were tested throughout nine states along the outer edges of the currently known A. planipennis infestation in North America. Trap catch was highest on fluon-coated green multifunnel traps, and trap detections at sites with low A. planipennis population density ranged from 72 to 76% for all trap and lure types tested. (3Z)-hexenol and (3Z)-lactone baited traps functioned as well as (3Z)-hexenol and manuka oil-baited traps. Independent of the lure used, detection rates on green fluon-coated multifunnel traps were comparable with glued purple prism traps in areas with low A. planipennis population densities.

An EPR study of positive hole transfer and trapping in irradiated frozen solutions containing aromatic traps

International Nuclear Information System (INIS)

Egorov, A.V.; Zezin, A.A.; Feldman, V.I.

2002-01-01

Complete text of publication follows. Processes of positive hole migration and trapping are of basic significance for understanding of the primary events in the radiation chemistry of solid molecular systems. Specific interest is concerned with the case, when ionization energies of 'hole traps' are rather close, so one may expect 'fine tuning' effects resulting from variations in conformation, weak interactions, molecular packing, etc. In this contribution we report the results of EPR study of formation of radical cations in irradiated frozen halocarbon solutions containing aromatic molecules of different structure. Using the 'two-trap' model made it possible to obtain an evidence for efficient long-range trap-to-trap positive hole transfer between alkyl benzene molecules with close ionization energies distributed in the matrices with high ionization potentials. The distance of transfer was found to be 2-4 nm. In the case of frozen solutions containing ethylbenzene and toluene, it was found that the efficiency and direction of hole transfer was controlled by the conformation of ethylbenzene radical cation. The study of positive hole localization in 'bridged' diphenyls of Ph(CH 2 ) n Ph type revealed that the structure of radical cations of these species was affected by local environment (type of halocarbon matrix) and the conformational flexibility of 'bridge'. In summary, we may conclude that migration and localization of positive hole in rigid systems containing aromatic 'traps' is quite sensitive to rather subtle effects. This conclusion may be of common significance for the radiation chemistry of systems with physical dispersion of the traps of similar chemical structure (e.g. macromolecules, adsorbed molecules, etc.)

Cold trap disposed within a tank

International Nuclear Information System (INIS)

Kanbe, Mitsuru.

1983-01-01

Purpose: To improve the reliability and the durability of cold traps by simplifying the structure and recycling liquid metals without using electromagnetic pumps. Constitution: The reactor container is partitioned by an intermediate container enhousing primary recycling pumps and cold traps. The inlet and the exit for the liquid metal of each cold trap are opened to the outside and the inside of the intermediate container respectively. In such a structure, the pressure difference between the inside and the outside of the intermediate container is exerted on the cold traps due to the exhaust pressure of the recycling pumps in which the liquid metal flowing into the cold traps is purified through filters, cooled and then discharged from the exit to the cold plenum. In this way, liquid metal can be recycled without using an electromagnetic pump whose reliability has not yet been established. (Kamimura, M.)

Nonadiabatic transitions in electrostatically trapped ammonia molecules

International Nuclear Information System (INIS)

Kirste, Moritz; Schnell, Melanie; Meijer, Gerard; Sartakov, Boris G.

2009-01-01

Nonadiabatic transitions are known to be major loss channels for atoms in magnetic traps but have thus far not been experimentally reported upon for trapped molecules. We have observed and quantified losses due to nonadiabatic transitions for three isotopologues of ammonia in electrostatic traps by comparing the trapping times in traps with a zero and a nonzero electric field at the center. Nonadiabatic transitions are seen to dominate the overall loss rate even for the present samples that are at relatively high temperatures of 30 mK. It is anticipated that losses due to nonadiabatic transitions in electric fields are omnipresent in ongoing experiments on cold molecules.

Prominent extraaxial CSF space on cranial ultrasound in infants: correlation with neurodevelopmental outcome

Energy Technology Data Exchange (ETDEWEB)

Kim, Bo Kyung; Lee, Mun Hyang; Yoon, Hye Kyung; Jung, Kyung Jae; Park, Won Soon; Chang, Yun Sil; Kim, Chan Gyo [Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)

1999-08-01

To determine the clinical significance of prominent extra-axial CSF space (EACSFS) in infants, as seen on cranial ultrasound. Between March 1996 and November 1997, all infants who had undergone head ultrasound at our institution and were found to have prominent EACSFS were evaluated. The width of the interhemispheric fissure was measured at three locations at the level of the frontal horn, body and atrium of the lateral ventricles. The depth of the CSF space over the convexity was also measured. The average of these measurements was calculated and each patient was assigned to one of three groups: mild, moderate, or marked. Ultrasound findings were evaluated for other associated abnormalities. Clinical neurodevelopment was evaluated by a pediatric neurologist, and ultrasound and neurodevelopmental findings were correlated. Prominent EACSFS was found in 153 patients, and neurodevelopmental evaluation up to a corrected age of 9 months was available in 133. One hundred and eight of 117 infants with normal neurodevelopment had no other associated abnormality(n=81), or abnormality associated only with grade I subependymal hemorrhage or cyst(n=27). Twelve of 16 infants with an abnormal neurodevelopmental outcome had major abnormalities including PVL, grade IV hemorrhage, and marked ventriculomegaly. Prominent EACSFS alone does not appear to be clinically significant. An abnormal neurodevelopmental outcome is associated with major abnormalities seen on ultrasound. Follow-up examination for prominent EACSFS is not indicated unless the associated abnormality requires further evaluations.

Prominent extraaxial CSF space on cranial ultrasound in infants: correlation with neurodevelopmental outcome

International Nuclear Information System (INIS)

Kim, Bo Kyung; Lee, Mun Hyang; Yoon, Hye Kyung; Jung, Kyung Jae; Park, Won Soon; Chang, Yun Sil; Kim, Chan Gyo

1999-01-01

To determine the clinical significance of prominent extra-axial CSF space (EACSFS) in infants, as seen on cranial ultrasound. Between March 1996 and November 1997, all infants who had undergone head ultrasound at our institution and were found to have prominent EACSFS were evaluated. The width of the interhemispheric fissure was measured at three locations at the level of the frontal horn, body and atrium of the lateral ventricles. The depth of the CSF space over the convexity was also measured. The average of these measurements was calculated and each patient was assigned to one of three groups: mild, moderate, or marked. Ultrasound findings were evaluated for other associated abnormalities. Clinical neurodevelopment was evaluated by a pediatric neurologist, and ultrasound and neurodevelopmental findings were correlated. Prominent EACSFS was found in 153 patients, and neurodevelopmental evaluation up to a corrected age of 9 months was available in 133. One hundred and eight of 117 infants with normal neurodevelopment had no other associated abnormality(n=81), or abnormality associated only with grade I subependymal hemorrhage or cyst(n=27). Twelve of 16 infants with an abnormal neurodevelopmental outcome had major abnormalities including PVL, grade IV hemorrhage, and marked ventriculomegaly. Prominent EACSFS alone does not appear to be clinically significant. An abnormal neurodevelopmental outcome is associated with major abnormalities seen on ultrasound. Follow-up examination for prominent EACSFS is not indicated unless the associated abnormality requires further evaluations

Falling drops skating on a film of air

Science.gov (United States)

Rubinstein, Shmuel

2012-02-01

When a raindrop hits a window, the surface immediately becomes wet as the water spreads. Indeed, this common observation of a drop impacting a surface is ubiquitous in our everyday experience. I will show that the impact of a drop on a surface is a much richer, more complex phenomenon than our simple experience may suggests: To completely wet the surface the drop must first expel all the air beneath it; however, this does not happened instantaneously. Instead, a very thin film of air, only a few tens of nanometers thick, remains trapped between the falling drop and the surface as the fluid spreads. The thin film of air serves to lubricate the drop enabling the fluid to skate laterally outward at strikingly high velocities. Simultaneously, the wetting fluid spreads inward at a much slower velocity, trapping a bubble of air within the drop. However, these events occur at diminutive length scales and fleeting time scales; therefore, to visualize them we develop new imaging modalities that are sensitive to the behavior right at the surface and that have time resolution superior to even the very fastest cameras. These imaging techniques reveal that the ultimate wetting of the surface occurs through a completely new mechanism, the breakup of the thin film of air through a spinodal like dewetting process that breaks the cylindrical symmetry of the impact and drives an anomalously rapid spreading of a wetting front. These results are in accord with recent theoretical predictions and challenge the prevailing paradigm in which contact between the liquid and solid occurs immediately, and spreading is dominated by the dynamics of a single contact line.

How to detect trap cluster systems?

International Nuclear Information System (INIS)

Mandowski, Arkadiusz

2008-01-01

Spatially correlated traps and recombination centres (trap-recombination centre pairs and larger clusters) are responsible for many anomalous phenomena that are difficult to explain in the framework of both classical models, i.e. model of localized transitions (LT) and the simple trap model (STM), even with a number of discrete energy levels. However, these 'anomalous' effects may provide a good platform for identifying trap cluster systems. This paper considers selected cluster-type effects, mainly relating to an anomalous dependence of TL on absorbed dose in the system of isolated clusters (ICs). Some consequences for interacting cluster (IAC) systems, involving both localized and delocalized transitions occurring simultaneously, are also discussed

Evaluation of the Tekmar 3100 Purge and Trap Agilent GC/MSD system for VOC analysis

Energy Technology Data Exchange (ETDEWEB)

Li, K.; Fingas, M.F. [Environment Canada, Ottawa, ON (Canada). Emergencies Science and Technology Div

2004-07-01

This presentation described the Tekmar automated purge and trap (PAT) modular analyzer for detecting and quantifying volatile organic compounds (VOCs) in relatively clean water samples. A large percentage of emergency response work involves VOC analysis under various matrices such as water or soil. PAT analysis is an extraction method in which the VOCs from a liquid sample are purged by helium and concentrated on an internal trap, where the analytes are thermally desorbed into a gas chromatograph or a gas chromatograph/mass spectrometer (GS/MS). This high degree of concentration results in good detection limits. The performance of the Tekmar PAT 31000 concentrator with autosampler and GC/MS system was evaluated using a 1 ppb and 100 ppb standard of the Method 524 mixture for some selected VOC on the list. The study also examined the purging parameters such as time and temperature. It also examined a new way of introducing gaseous samples through the 3-way purge vessel valve on the concentrator. The objective was to determine if the versatility of the system could be extended by using the the same instrument configuration for air sampling. Preliminary results indicate that it is not yet practical to use the system for air sampling. 3 tabs., 4 figs.

The LPCTrap facility for in-trap decay experiments

International Nuclear Information System (INIS)

Rodriguez, D.; Ban, G.; Durand, D.; Duval, F.; Flechard, X.; Herbane, M.; Lienard, E.; Mauger, F.; Mery, A.; Naviliat-Cuncic, O.; Thomas, J.-C.

2007-01-01

The LPCTrap facility is coupled to the low-energy beam line LIRAT of the SPIRAL source at GANIL (France). The facility comprises an RFQ trap for beam preparation and a transparent Paul trap for in-trap decay studies. The system has been tested for several ion species. The Paul trap has been fully characterized for 6 Li + and 23 Na + ions. This characterization together with GEANT4 simulations of the in-trap decay setup (Paul trap and detection system) has permitted to predict the effect of the size of the ion cloud on the decay study of 6 He + .

Line-Trapping of Codling Moth (Lepidoptera: Tortricidae): A Novel Approach to Improving the Precision of Capture Numbers in Traps Monitoring Pest Density.

Science.gov (United States)

Adams, C G; McGhee, P S; Schenker, J H; Gut, L J; Miller, J R

2017-08-01

This field study of codling moth, Cydia pomonella (L.), response to single versus multiple monitoring traps baited with codlemone demonstrates that precision of a given capture number is alarmingly poor when the population is held constant by releasing moths. Captures as low as zero and as high as 12 males per single trap are to be expected where the catch mode is three. Here, we demonstrate that the frequency of false negatives and overestimated positives for codling moth trapping can be substantially reduced by employing the tactic of line-trapping, where five traps were deployed 4 m apart along a row of apple trees. Codling moth traps spaced closely competed only slightly. Therefore, deploying five traps closely in a line is a sampling technique nearly as good as deploying five traps spaced widely. But line trapping offers a substantial savings in time and therefore cost when servicing aggregated versus distributed traps. As the science of pest management matures by mastering the ability to translate capture numbers into estimates of absolute pest density, it will be important to employ a tactic like line-trapping so as to shrink the troublesome variability associated with capture numbers in single traps that thwarts accurate decisions about if and when to spray. Line-trapping might similarly increase the reliability and utility of density estimates derived from capture numbers in monitoring traps for various pest and beneficial insects. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Medfly female attractant trapping studies in Guatemala

International Nuclear Information System (INIS)

Jeronimo, F.; Rendon, P.; Villatoro, C.

1999-01-01

Experiments were conducted from 1994 - 1998 to test the attractiveness of combinations of food-based chemicals for C. capitata (medfly) in Guatemala. Most studies were done in coffee. The 1995 studies, using the FA-2 attractants (ammonium acetate and putrescine) showed that this combination was attractive for females and had potential for use in conjunction with a SIT program. The 1996 studies at three elevations demonstrated that, in general, these attractants, when used in either the Open Bottom Dry Trap (OBDT), Closed Bottom Dry Trap (CBDT), or International Pheromone's McPhail Trap (IPMT) performed better than the Jumbo McPhail trap (JMT) baited with NuLure and borax (NU+B) for capture of feral females. At the high elevation (1400 m), the IPMT with FA-2 and OBDT with FA-2 were best; at the middle elevation (1100 m), the ORDT, IPMT, and CBDT with FA-2 were best; and at low elevations (659 m), the IPMT with FA-2, JMT with NU+B and ORDT with FA-2 were equal in performance. At the middle elevation, using sterile flies, the OBDT with FA-2 worked best. When experiments were carried out in pear, the traps using the FA-2 attractants captured more female flies than the JMT, NU+B, but not significantly more. During the 1997 trials, a third component, trimethylamine was added to the two component lure (FA-3). This attractant was tested in a number of locally produced traps using 2 I soft drink bottles with different color bottoms. The dry versions of the traps contained a yellow sticky insert. All study sites were at low elevation 600 - 650 m, in coffee, testing both sterile and feral flies. With the feral flies during the first phase of the study at finca San Carlos, there were no significant differences between treatments, at finca San Luis, the clear local trap with sticky insert and the green local trap with sticky insert were best, and at finca Valapraiso, the green local trap with yellow sticky insert and yellow local trap with sticky insert captured more flies

Trapping technology for gaseous fission products from voloxidation process

International Nuclear Information System (INIS)

Shin, Jin Myeong; Park, J. J.; Park, G. I.; Jung, I. H.; Lee, H. H.; Kim, G. H.; Yang, M. S.

2005-05-01

The objective of this report is to review the different technologies for trapping the gaseous wastes containing Cs, Ru, Tc, 14 C, Kr, Xe, I and 3 H from a voloxidation process. Based on literature reviews and KAERI's experimental results on the gaseous fission products trapping, appropriate trapping method for each fission product has been selected considering process reliability, simplicity, decontamination factor, availability, and disposal. Specifically, the most promising trapping method for each fission product has been proposed for the development of the INL off-gas trapping system. A fly ash filter is proposed as a trapping media for a cesium trapping unit. In addition, a calcium filter is proposed as a trapping media for ruthenium, technetium, and 14 C trapping unit. In case of I trapping unit, AgX is proposed. For Kr and Xe, adsorption on solid is proposed. SDBC (Styrene Divinyl Benzene Copolymer) is also proposed as a conversion media to HTO for 3 H. This report will be used as a useful means for analyzing the known trapping technologies and help selecting the appropriate trapping methods for trapping volatile and semi-volatile fission products, long-lived fission products, and major heat sources generated from a voloxidation process. It can also be used to design an off-gas treatment system

High-fidelity operations in microfabricated surface ion traps

Science.gov (United States)

Maunz, Peter

2017-04-01

Trapped ion systems can be used to implement quantum computation as well as quantum simulation. To scale these systems to the number of qubits required to solve interesting problems in quantum chemistry or solid state physics, the use of large multi-zone ion traps has been proposed. Microfabrication enables the realization of surface electrode ion traps with complex electrode structures. While these traps may enable the scaling of trapped ion quantum information processing (QIP), microfabricated ion traps also pose several technical challenges. Here, we present Sandia's trap fabrication capabilities and characterize trap properties and shuttling operations in our most recent high optical access trap (HOA-2). To demonstrate the viability of Sandia's microfabricated ion traps for QIP we realize robust single and two-qubit gates and characterize them using gate set tomography (GST). In this way we are able to demonstrate the first single qubit gates with a diamond norm of less than 1 . 7 ×10-4 , below a rigorous fault tolerance threshold for general noise of 6 . 7 ×10-4. Furthermore, we realize Mølmer-Sørensen two qubit gates with a process fidelity of 99 . 58(6) % also characterized by GST. These results demonstrate the viability of microfabricated surface traps for state of the art quantum information processing demonstrations. This research was funded, in part, by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA).

Biases in Drosophila melanogaster protein trap screens

Directory of Open Access Journals (Sweden)

Müller Ilka

2009-05-01

Full Text Available Abstract Background The ability to localise or follow endogenous proteins in real time in vivo is of tremendous utility for cell biology or systems biology studies. Protein trap screens utilise the random genomic insertion of a transposon-borne artificial reporter exon (e.g. encoding the green fluorescent protein, GFP into an intron of an endogenous gene to generate a fluorescent fusion protein. Despite recent efforts aimed at achieving comprehensive coverage of the genes encoded in the Drosophila genome, the repertoire of genes that yield protein traps is still small. Results We analysed the collection of available protein trap lines in Drosophila melanogaster and identified potential biases that are likely to restrict genome coverage in protein trap screens. The protein trap screens investigated here primarily used P-element vectors and thus exhibit some of the same positional biases associated with this transposon that are evident from the comprehensive Drosophila Gene Disruption Project. We further found that protein trap target genes usually exhibit broad and persistent expression during embryonic development, which is likely to facilitate better detection. In addition, we investigated the likely influence of the GFP exon on host protein structure and found that protein trap insertions have a significant bias for exon-exon boundaries that encode disordered protein regions. 38.8% of GFP insertions land in disordered protein regions compared with only 23.4% in the case of non-trapping P-element insertions landing in coding sequence introns (p -4. Interestingly, even in cases where protein domains are predicted, protein trap insertions frequently occur in regions encoding surface exposed areas that are likely to be functionally neutral. Considering the various biases observed, we predict that less than one third of intron-containing genes are likely to be amenable to trapping by the existing methods. Conclusion Our analyses suggest that the

Air-stable, solution-processed oxide p-n heterojunction ultraviolet photodetector.

Science.gov (United States)

Kim, Do Young; Ryu, Jiho; Manders, Jesse; Lee, Jaewoong; So, Franky

2014-02-12

Air-stable solution processed all-inorganic p-n heterojunction ultraviolet photodetector is fabricated with a high gain (EQE, 25 300%). Solution-processed NiO and ZnO films are used as p-type and n-type ultraviolet sensitizing materials, respectively. The high gain in the detector is due to the interfacial trap-induced charge injection that occurs at the ITO/NiO interface by photogenerated holes trapped in the NiO film. The gain of the detector is controlled by the post-annealing temperature of the solution-processed NiO films, which are studied by X-ray photoelectron spectroscopy (XPS).

Magnetic trapping of cold bromine atoms.

Science.gov (United States)

Rennick, C J; Lam, J; Doherty, W G; Softley, T P

2014-01-17

Magnetic trapping of bromine atoms at temperatures in the millikelvin regime is demonstrated for the first time. The atoms are produced by photodissociation of Br2 molecules in a molecular beam. The lab-frame velocity of Br atoms is controlled by the wavelength and polarization of the photodissociation laser. Careful selection of the wavelength results in one of the pair of atoms having sufficient velocity to exactly cancel that of the parent molecule, and it remains stationary in the lab frame. A trap is formed at the null point between two opposing neodymium permanent magnets. Dissociation of molecules at the field minimum results in the slowest fraction of photofragments remaining trapped. After the ballistic escape of the fastest atoms, the trapped slow atoms are lost only by elastic collisions with the chamber background gas. The measured loss rate is consistent with estimates of the total cross section for only those collisions transferring sufficient kinetic energy to overcome the trapping potential.

Trapping and dark current in plasma-based accelerators

International Nuclear Information System (INIS)

Schroder, C.B.; Esarey, E.; Shadwick, B.A.; Leemans, W.P.

2004-01-01

The trapping of thermal electrons in a nonlinear plasma wave of arbitrary phase velocity is investigated. The threshold plasma wave amplitude for trapping plasma electrons is calculated, thereby determining the fraction trapped and the expected dark current in a plasma-based accelerator. It is shown that the presence of a laser field (e.g., trapping in the self-modulated regime of the laser wakefield accelerator) increases the trapping threshold. Implications for experimental and numerical laser-plasma studies are discussed

Solar Prominences Embedded in Flux Ropes: Morphological Features and Dynamics from 3D MHD Simulations

Science.gov (United States)

Terradas, J.; Soler, R.; Luna, M.; Oliver, R.; Ballester, J. L.; Wright, A. N.

2016-04-01

The temporal evolution of a solar prominence inserted in a three-dimensional magnetic flux rope is investigated numerically. Using the model of Titov & Démoulin under the regime of weak twist, the cold and dense prominence counteracts gravity by modifying the initially force-free magnetic configuration. In some cases a quasi-stationary situation is achieved after the relaxation phase, characterized by the excitation of standing vertical oscillations. These oscillations show a strong attenuation with time produced by the mechanism of continuum damping due to the inhomogeneous transition between the prominence and solar corona. The characteristic period of the vertical oscillations does not depend strongly on the twist of the flux rope. Nonlinearity is responsible for triggering the Kelvin-Helmholtz instability associated with the vertical oscillations and that eventually produces horizontal structures. Contrary to other configurations in which the longitudinal axis of the prominence is permeated by a perpendicular magnetic field, like in unsheared arcades, the orientation of the prominence along the flux rope axis prevents the development of Rayleigh-Taylor instabilities and therefore the appearance of vertical structuring along this axis.

Metastable self-trapping of positrons in MgO

Science.gov (United States)

Monge, M. A.; Pareja, R.; González, R.; Chen, Y.

1997-01-01

Low-temperature positron annihilation measurements have been performed on MgO single crystals containing either cation or anion vacancies. The temperature dependence of the S parameter is explained in terms of metastable self-trapped positrons which thermally hop through the crystal lattice. The experimental results are analyzed using a three-state trapping model assuming transitions from both delocalized and self-trapped states to deep trapped states at vacancies. The energy level of the self-trapped state was determined to be (62+/-5) meV above the delocalized state. The activation enthalpy for the hopping process of self-trapped positrons appears to depend on the kind of defect present in the crystals.

Leaf-air transfer of organochlorine pesticides from three selected vegetables

Energy Technology Data Exchange (ETDEWEB)

Yang Xinglun [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008 (China); Jiang Xin [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008 (China)]. E-mail: jiangxin@issas.ac.cn; Yu Guifen [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008 (China); Yao Fenxia [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008 (China); Bian Yongrong [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008 (China); Wang Fang [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008 (China)

2007-07-15

The leaf-air transfer of organochlorine pesticides (OCPs) in three kinds of vegetables, namely lettuce, romaine and garlic leaves was investigated. It was found that although the uptake of OCPs by the three selected vegetables was similar under controlled conditions, the depuration varied significantly among chemicals and plant species in terms of elimination rate, final residue of each OCPs, as well as the effect of temperature on the residue of OCPs in the vegetables. The results indicated that neither QCB nor HCB could be trapped tightly by any of the three selected vegetables, in contrast, p,p'-DDT could be retained effectively by all of them; the retainment of {alpha}-HCH, {gamma}-HCH, p,p'-DDE, was dependent on the vegetable species, of which the garlic leaf had the biggest ability to trap them. Our work provided insight into the behavior of OCPs in the agroecosystem. - The leaf-air transfer of OCPs varied significantly among chemicals and the three selected vegetables.

Leaf-air transfer of organochlorine pesticides from three selected vegetables

International Nuclear Information System (INIS)

Yang Xinglun; Jiang Xin; Yu Guifen; Yao Fenxia; Bian Yongrong; Wang Fang

2007-01-01

The leaf-air transfer of organochlorine pesticides (OCPs) in three kinds of vegetables, namely lettuce, romaine and garlic leaves was investigated. It was found that although the uptake of OCPs by the three selected vegetables was similar under controlled conditions, the depuration varied significantly among chemicals and plant species in terms of elimination rate, final residue of each OCPs, as well as the effect of temperature on the residue of OCPs in the vegetables. The results indicated that neither QCB nor HCB could be trapped tightly by any of the three selected vegetables, in contrast, p,p'-DDT could be retained effectively by all of them; the retainment of α-HCH, γ-HCH, p,p'-DDE, was dependent on the vegetable species, of which the garlic leaf had the biggest ability to trap them. Our work provided insight into the behavior of OCPs in the agroecosystem. - The leaf-air transfer of OCPs varied significantly among chemicals and the three selected vegetables

Possibilities for achieving antihydrogen recombination and trapping using a nested Penning trap and a magnetic well

International Nuclear Information System (INIS)

Ordonez, C.A.; Dolliver, D.D.; Chang Yongbin; Correa, J. R.

2002-01-01

A theoretical study is presented regarding some possibilities for achieving antihydrogen recombination and trapping using a nested Penning trap and a magnetic well. The work reported consists of a review, an extension, and applications of the relevant knowledge base. A nested Penning trap produces a magnetic field, which provides plasma confinement perpendicular to the magnetic field, and an electric field associated with a nested-well potential profile. The nested-well potential profile provides plasma confinement parallel to the magnetic field for oppositely signed plasma species that can have overlapping confinement regions. A configuration is considered in which the electric field is applied in two regions of uniform magnetic field that reside on opposite sides of a magnetic well region. The electric field confines overlapping positron and antiproton plasmas, which thread the magnetic well region. The magnetic well region would serve to trap a fraction of any antihydrogen atoms that are formed. Two different methods are considered for achieving overlap of positron and antiproton plasmas. For each, a set of conditions is predicted for achieving antihydrogen recombination and trapping. Although the study reported specifically considers simultaneous confinement of positron and antiproton plasmas in nested Penning traps, much of the information presented is also relevant to the prospect of merging other pairs of oppositely signed plasmas (e.g., electron and positron plasmas)

Geometric light trapping with a V-trap for efficient organic solar cells

KAUST Repository

Kim, Soo Jin

2013-03-14

The efficiency of today’s most efficient organic solar cells is primarily limited by the ability of the active layer to absorb all the sunlight. While internal quantum efficiencies exceeding 90% are common, the external quantum efficiency rarely exceeds 70%. Light trapping techniques that increase the ability of a given active layer to absorb light are common in inorganic solar cells but have only been applied to organic solar cells with limited success. Here, we analyze the light trapping mechanism for a cell with a V-shape substrate configuration and demonstrate significantly improved photon absorption in an 5.3%-efficient PCDTBT:PC70BM bulk heterojunction polymer solar cell. The measured short circuit current density improves by 29%, in agreement with model predictions, and the power conversion efficiency increases to 7.2%, a 35% improvement over the performance in the absence of a light trap.

Trapping technology for gaseous fission products from voloxidation process

Energy Technology Data Exchange (ETDEWEB)

Shin, Jin Myeong; Park, J. J.; Park, G. I.; Jung, I. H.; Lee, H. H.; Kim, G. H.; Yang, M. S

2005-05-15

The objective of this report is to review the different technologies for trapping the gaseous wastes containing Cs, Ru, Tc, {sup 14}C, Kr, Xe, I and {sup 3}H from a voloxidation process. Based on literature reviews and KAERI's experimental results on the gaseous fission products trapping, appropriate trapping method for each fission product has been selected considering process reliability, simplicity, decontamination factor, availability, and disposal. Specifically, the most promising trapping method for each fission product has been proposed for the development of the INL off-gas trapping system. A fly ash filter is proposed as a trapping media for a cesium trapping unit. In addition, a calcium filter is proposed as a trapping media for ruthenium, technetium, and {sup 14}C trapping unit. In case of I trapping unit, AgX is proposed. For Kr and Xe, adsorption on solid is proposed. SDBC (Styrene Divinyl Benzene Copolymer) is also proposed as a conversion media to HTO for {sup 3}H. This report will be used as a useful means for analyzing the known trapping technologies and help selecting the appropriate trapping methods for trapping volatile and semi-volatile fission products, long-lived fission products, and major heat sources generated from a voloxidation process. It can also be used to design an off-gas treatment system.

Vapour trap development and operational experience

International Nuclear Information System (INIS)

Jansing, W.; Kirchner, G.; Menck, J.

1977-01-01

Sodium aerosols have the unpleasant characteristic that they deposit at places with low temperature level. This effect can be utilized when sodium aerosols are to be trapped at places which are determined beforehand. Thus vapour traps were developed which can filter sodium vapour from the cover gas. By this means the necessity was eliminated to heat all gas lines and gas systems with trace heaters just as all sodium lines are heated. It was of special interest for the INTERATOM to develop vapour traps which must not be changed or cleaned after a certain limited operating period. The vapour traps were supposed to enable maintenance free operation, i.e. they were to operate 'self cleaning'

Flux trapping in superconducting cavities

International Nuclear Information System (INIS)

Vallet, C.; Bolore, M.; Bonin, B.; Charrier, J.P.; Daillant, B.; Gratadour, J.; Koechlin, F.; Safa, H.

1992-01-01

The flux trapped in various field cooled Nb and Pb samples has been measured. For ambient fields smaller than 3 Gauss, 100% of the flux is trapped. The consequences of this result on the behavior of superconducting RF cavities are discussed. (author) 12 refs.; 2 figs

Achieving Translationally Invariant Trapped Ion Rings

Science.gov (United States)

Urban, Erik; Li, Hao-Kun; Noel, Crystal; Hemmerling, Boerge; Zhang, Xiang; Haeffner, Hartmut

2017-04-01

We present the design and implementation of a novel surface ion trap design in a ring configuration. By eliminating the need for wire bonds through the use of electrical vias and using a rotationally invariant electrode configuration, we have realized a trap that is able to trap up to 20 ions in a ring geometry 45um in diameter, 400um above the trap surface. This large trapping height to ring diameter ratio allows for global addressing of the ring with both lasers and electric fields in the chamber, thereby increasing our ability to control the ring as a whole. Applying compensating electric fields, we measure very low tangential trap frequencies (less than 20kHz) corresponding to rotational barriers down to 4mK. This measurement is currently limited by the temperature of the ions but extrapolation indicates the barrier can be reduced much further with more advanced cooling techniques. Finally, we show that we are able to reduce this energy barrier sufficiently such that the ions are able to overcome it either through thermal motion or rotational motion and delocalize over the full extent of the ring. This work was funded by the Keck Foundation and the NSF.

Mini ion trap mass spectrometer

Science.gov (United States)

Dietrich, D.D.; Keville, R.F.

1995-09-19

An ion trap is described which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10{sup 9} and commercial mass spectrometers requiring 10{sup 4} ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products. 10 figs.

Prominence modelling: from observed emission measures to temperature profiles

Czech Academy of Sciences Publication Activity Database

Anzer, U.; Heinzel, Petr

2008-01-01

Roč. 480, č. 2 (2008), s. 537-542 ISSN 0004-6361 Grant - others:EU(XE) ESA-PECS Project No. 98030 Institutional research plan: CEZ:AV0Z10030501 Keywords : Sun * prominences * transition region Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.153, year: 2008

Ion bunch stacking in a Penning trap after purification in an electrostatic mirror trap

CERN Document Server

Rosenbusch, M; Blaum, K; Borgmann, Ch; Kreim, S; Lunney, D; Manea, V; Schweikhard, L; Wienholtz, F; Wolf, R N

2014-01-01

The success of many measurements in analytical mass spectrometry as well as in precision mass determinations for atomic and nuclear physics is handicapped when the ion sources deliver ``contaminations'', i.e., unwanted ions of masses similar to those of the ions of interest. In particular, in ion-trapping devices, large amounts of contaminant ions result in significant systematic errors-if the measurements are possible at all. We present a solution for such cases: The ions from a quasi-continuous source are bunched in a linear radio-frequency-quadrupole ion trap, separated by a multi-reflection time-of-flight section followed by a Bradbury-Nielsen gate, and then captured in a Penning trap. Buffer-gas cooling is used to damp the ion motion in the latter, which allows a repeated opening of the Penning trap for a stacking of mass-selected ion bunches. Proof-of-principle demonstrations have been performed with the ISOLTRAP setup at ISOLDE/CERN, both with Cs-133(+) ions from an off-line ion source and by applicati...

Ripple Trap

Science.gov (United States)

2006-01-01

3 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the margin of a lava flow on a cratered plain in the Athabasca Vallis region of Mars. Remarkably, the cratered plain in this scene is essentially free of bright, windblown ripples. Conversely, the lava flow apparently acted as a trap for windblown materials, illustrated by the presence of the light-toned, wave-like texture over much of the flow. That the lava flow surface trapped windblown sand and granules better than the cratered plain indicates that the flow surface has a rougher texture at a scale too small to resolve in this image. Location near: 10.7oN, 204.5oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

Density of Trap States and Auger-mediated Electron Trapping in CdTe Quantum-Dot Solids

NARCIS (Netherlands)

Boehme, Simon C.; Mikel Azpiroz, Jon; Aulin, Yaroslav V.; Grozema, Ferdinand C.; Vanmaekelbergh, Daniel; Siebbeles, Laurens D. A.; Infante, Ivan; Houtepen, Arjan J.

Charge trapping is an ubiquitous process in colloidal quantum-dot solids and a major limitation to the efficiency of quantum dot based devices such as solar cells, LEDs, and thermoelectrics. Although empirical approaches led to a reduction of trapping and thereby efficiency enhancements, the exact

Density of trap states and Auger-mediated electron trapping in CdTe quantum-dot solids

NARCIS (Netherlands)

Boehme, Simon C.; Azpiroz, Jon Mikel; Aulin, Yaroslav V.; Grozema, Ferdinand C.; Vanmaekelbergh, Daniël; Siebbeles, Laurens D A; Infante, Ivan; Houtepen, Arjan J.

2015-01-01

Charge trapping is an ubiquitous process in colloidal quantum-dot solids and a major limitation to the efficiency of quantum dot based devices such as solar cells, LEDs, and thermoelectrics. Although empirical approaches led to a reduction of trapping and thereby efficiency enhancements, the exact

Deuterium transport and trapping in polycrystalline tungsten

International Nuclear Information System (INIS)

Anderl, R.A.; Holland, D.F.; Longhurst, G.R.; Pawelko, R.J.; Trybus, C.L.; Sellers, C.H.

1992-01-01

This paper reports that deuterium permeation studies for polycrystalline tungsten foil have been conducted to provide data for estimating tritium transport and trapping in tungsten-clad divertors proposed for advanced fusion-reactor concepts. Based on a detailed transmission electron microscopy (TEM) microstructural characterization of the specimen material and on analyses of permeation data measured at temperatures ranging form 610 to 823 K for unannealed and annealed tungsten foil (25 μm thick), the authors note the following key results: deuterium transport in tungsten foil is dominated by extensive trapping that varies inversely with prior anneal temperatures of the foil material, the reduction in the trapped fraction correlates with a corresponding elimination of a high density of dislocations in cell-wall structures introduced during the foil fabrication process, trapping behavior in these foils can be modelled using trap energies between 1.3 eV and 1.5 eV and trap densities ranging from 1 x 10 -5 atom fraction

Ion trap device

Science.gov (United States)

Ibrahim, Yehia M.; Smith, Richard D.

2016-01-26

An ion trap device is disclosed. The device includes a series of electrodes that define an ion flow path. A radio frequency (RF) field is applied to the series of electrodes such that each electrode is phase shifted approximately 180 degrees from an adjacent electrode. A DC voltage is superimposed with the RF field to create a DC gradient to drive ions in the direction of the gradient. A second RF field or DC voltage is applied to selectively trap and release the ions from the device. Further, the device may be gridless and utilized at high pressure.

Word-level prominence in Persian: An Experimental Study.

Science.gov (United States)

Sadeghi, Vahid

2017-12-01

Previous literature on the phonetics of stress in Persian has reported that fundamental frequency is the only reliable acoustic correlate of stress, and that stressed and unstressed syllables are not differentiated from each other in the absence of accentuation. In this study, the effects of lexical stress on duration, overall intensity and spectral tilt were examined in Persian both in the accented and unaccented conditions. Results showed that syllable duration is consistently affected by stress in Persian in both the accented and unaccented conditions across all vowel types. Unlike duration, the results for overall intensity and spectral tilt were significant only in the accented condition, suggesting that measures of intensity are not a correlate of stress in Persian but they are mainly caused by the presence of a pitch movement. The findings are phonologically interpreted as suggesting that word-level prominence in Persian is typologically similar to 'stress accent' languages, in which multiple phonetic cues are used to signal the prominence contrast in the accented condition, and stressed and unstressed syllables are different from each other even when the word is not pitch-accented.

21 CFR 868.5995 - Tee drain (water trap).

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tee drain (water trap). 868.5995 Section 868.5995...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5995 Tee drain (water trap). (a) Identification. A tee drain (water trap) is a device intended to trap and drain water that collects in ventilator...

(Anti)hydrogen recombination studies in a nested Penning trap

International Nuclear Information System (INIS)

Quint, W.; Kaiser, R.; Hall, D.; Gabrielse, G.

1993-01-01

Extremely cold antiprotons, stored in Penning trap at 4 K, open the way toward the production and study of cold antihydrogen. We have begun experimentally investigating the possibility to recombine cold positrons and antiprotons within nested Penning traps. Trap potentials are adjusted to allow cold trapped protons (and positive helium ions) to pass through cold trapped electrons. Electrons, protons and ions are counted by ejecting them to a cold channel plate and by nondestructive radiofrequency techniques. The effect of the space charge of one trapped species upon another trapped species passing through is clearly observed. (orig.)

Stability of Trapped Electrons in SiO(2)

International Nuclear Information System (INIS)

Fleetwood, D.M.; Winokur, P.S.

1999-01-01

Thermally stimulated current and capacitance voltage methods are used to investigate the thermal stability of trapped electrons associated with radiation-induced trapped positive charge in metal-oxide-semiconductor capacitors. The density of deeply trapped electrons in radiation-hardened 45 nm oxides exceeds that of shallow electrons by a factor of ∼3 after radiation exposure, and by up to a factor of 10 or more during biased annealing. Shallow electron traps anneal faster than deep traps, and seem to be at least qualitatively consistent with the model of Lelis et al. Deeper traps maybe part of a fundamentally distinct dipole complex, and/or have shifted energy levels that inhibit charge exchange with the Si

An Open Standard for Camera Trap Data

NARCIS (Netherlands)

Forrester, Tavis; O'Brien, Tim; Fegraus, Eric; Jansen, P.A.; Palmer, Jonathan; Kays, Roland; Ahumada, Jorge; Stern, Beth; McShea, William

2016-01-01

Camera traps that capture photos of animals are a valuable tool for monitoring biodiversity. The use of camera traps is rapidly increasing and there is an urgent need for standardization to facilitate data management, reporting and data sharing. Here we offer the Camera Trap Metadata Standard as an

A Computer Model of Insect Traps in a Landscape

Science.gov (United States)

Manoukis, Nicholas C.; Hall, Brian; Geib, Scott M.

2014-11-01

Attractant-based trap networks are important elements of invasive insect detection, pest control, and basic research programs. We present a landscape-level, spatially explicit model of trap networks, focused on detection, that incorporates variable attractiveness of traps and a movement model for insect dispersion. We describe the model and validate its behavior using field trap data on networks targeting two species, Ceratitis capitata and Anoplophora glabripennis. Our model will assist efforts to optimize trap networks by 1) introducing an accessible and realistic mathematical characterization of the operation of a single trap that lends itself easily to parametrization via field experiments and 2) allowing direct quantification and comparison of sensitivity between trap networks. Results from the two case studies indicate that the relationship between number of traps and their spatial distribution and capture probability under the model is qualitatively dependent on the attractiveness of the traps, a result with important practical consequences.

Fast and slow border traps in MOS devices

International Nuclear Information System (INIS)

Fleetwood, D.M.

1996-01-01

Convergent lines of evidence are reviewed which show that near-interfacial oxide traps (border traps) that exchange charge with the Si can strongly affect the performance, radiation response, and long-term reliability of MOS devices. Observable effects of border traps include capacitance-voltage (C-V) hysteresis, enhanced l/f noise, compensation of trapped holes, and increased thermally stimulated current in MOS capacitors. Effects of faster (switching times between ∼10 -6 s and ∼1 s) and slower (switching times greater than ∼1 s) border traps have been resolved via a dual-transistor technique. In conjunction with studies of MOS electrical response, electron paramagnetic resonance and spin dependent recombination studies suggest that E' defects (trivalent Si centers in SiO 2 associated with O vacancies) can function as border traps in MOS devices exposed to ionizing radiation or high-field stress. Hydrogen-related centers may also be border traps

Tic Tac TOE: Effects of Predictability and Importance on Acoustic Prominence in Language Production

Science.gov (United States)

Watson, Duane G.; Arnold, Jennifer E.; Tanenhaus, Michael K.

2008-01-01

Importance and predictability each have been argued to contribute to acoustic prominence. To investigate whether these factors are independent or two aspects of the same phenomenon, naive participants played a verbal variant of Tic Tac Toe. Both importance and predictability contributed independently to the acoustic prominence of a word, but in…

Electron densities in quiescent prominences derived from eclipse observations

Czech Academy of Sciences Publication Activity Database

Jejčič, S.; Heinzel, Petr

2009-01-01

Roč. 254, č. 1 (2009), s. 89-100 ISSN 0038-0938 Grant - others:EU(XE) ESA-PECS project No. 98030 Institutional research plan: CEZ:AV0Z10030501 Keywords : prominences quiescent * eclipse observations * visible spectrum Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.628, year: 2009

A reservoir trap for antiprotons

CERN Document Server

Smorra, Christian; Franke, Kurt; Nagahama, Hiroki; Schneider, Georg; Higuchi, Takashi; Van Gorp, Simon; Blaum, Klaus; Matsuda, Yasuyuki; Quint, Wolfgang; Walz, Jochen; Yamazaki, Yasunori; Ulmer, Stefan

2015-01-01

We have developed techniques to extract arbitrary fractions of antiprotons from an accumulated reservoir, and to inject them into a Penning-trap system for high-precision measurements. In our trap-system antiproton storage times > 1.08 years are estimated. The device is fail-safe against power-cuts of up to 10 hours. This makes our planned comparisons of the fundamental properties of protons and antiprotons independent from accelerator cycles, and will enable us to perform experiments during long accelerator shutdown periods when background magnetic noise is low. The demonstrated scheme has the potential to be applied in many other precision Penning trap experiments dealing with exotic particles.

Active stabilization of ion trap radiofrequency potentials

Energy Technology Data Exchange (ETDEWEB)

Johnson, K. G.; Wong-Campos, J. D.; Restelli, A.; Landsman, K. A.; Neyenhuis, B.; Mizrahi, J.; Monroe, C. [Joint Quantum Institute and University of Maryland Department of Physics, College Park, Maryland 20742 (United States)

2016-05-15

We actively stabilize the harmonic oscillation frequency of a laser-cooled atomic ion confined in a radiofrequency (rf) Paul trap by sampling and rectifying the high voltage rf applied to the trap electrodes. We are able to stabilize the 1 MHz atomic oscillation frequency to be better than 10 Hz or 10 ppm. This represents a suppression of ambient noise on the rf circuit by 34 dB. This technique could impact the sensitivity of ion trap mass spectrometry and the fidelity of quantum operations in ion trap quantum information applications.

Laser induced fluorescence of trapped molecular ions

Energy Technology Data Exchange (ETDEWEB)

Grieman, F.J.

1979-10-01

An experimental apparatus for obtaining the optical spectra of molecular ions is described. The experimental technique includes the use of three dimensional ion trapping, laser induced fluorescence, and gated photon counting methods. The ions, which are produced by electron impact, are confined in a radio-frequency quadrupole ion trap of cylindrical design. Because the quadrupole ion trap allows mass selection of the molecular ion desired for study, the analysis of the spectra obtained is greatly simplified. The ion trap also confines the ions to a region easily probed by a laser beam. 18 references.

Laser induced fluorescence of trapped molecular ions

International Nuclear Information System (INIS)

Grieman, F.J.

1979-10-01

An experimental apparatus for obtaining the optical spectra of molecular ions is described. The experimental technique includes the use of three dimensional ion trapping, laser induced fluorescence, and gated photon counting methods. The ions, which are produced by electron impact, are confined in a radio-frequency quadrupole ion trap of cylindrical design. Because the quadrupole ion trap allows mass selection of the molecular ion desired for study, the analysis of the spectra obtained is greatly simplified. The ion trap also confines the ions to a region easily probed by a laser beam. 18 references

Microfabricated Microwave-Integrated Surface Ion Trap

Science.gov (United States)

Revelle, Melissa C.; Blain, Matthew G.; Haltli, Raymond A.; Hollowell, Andrew E.; Nordquist, Christopher D.; Maunz, Peter

2017-04-01

Quantum information processing holds the key to solving computational problems that are intractable with classical computers. Trapped ions are a physical realization of a quantum information system in which qubits are encoded in hyperfine energy states. Coupling the qubit states to ion motion, as needed for two-qubit gates, is typically accomplished using Raman laser beams. Alternatively, this coupling can be achieved with strong microwave gradient fields. While microwave radiation is easier to control than a laser, it is challenging to precisely engineer the radiated microwave field. Taking advantage of Sandia's microfabrication techniques, we created a surface ion trap with integrated microwave electrodes with sub-wavelength dimensions. This multi-layered device permits co-location of the microwave antennae and the ion trap electrodes to create localized microwave gradient fields and necessary trapping fields. Here, we characterize the trap design and present simulated microwave performance with progress towards experimental results. This research was funded, in part, by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA).

SOLAR PROMINENCES EMBEDDED IN FLUX ROPES: MORPHOLOGICAL FEATURES AND DYNAMICS FROM 3D MHD SIMULATIONS

Energy Technology Data Exchange (ETDEWEB)

Terradas, J.; Soler, R.; Oliver, R.; Ballester, J. L. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Luna, M. [Instituto de Astrofsíca de Canarias, E-38205 La Laguna, Tenerife (Spain); Wright, A. N., E-mail: jaume.terradas@uib.es [School of Mathematics and Statistics, University of St Andrews, St Andrews, KY16 9SS (United Kingdom)

2016-04-01

The temporal evolution of a solar prominence inserted in a three-dimensional magnetic flux rope is investigated numerically. Using the model of Titov and Démoulin under the regime of weak twist, the cold and dense prominence counteracts gravity by modifying the initially force-free magnetic configuration. In some cases a quasi-stationary situation is achieved after the relaxation phase, characterized by the excitation of standing vertical oscillations. These oscillations show a strong attenuation with time produced by the mechanism of continuum damping due to the inhomogeneous transition between the prominence and solar corona. The characteristic period of the vertical oscillations does not depend strongly on the twist of the flux rope. Nonlinearity is responsible for triggering the Kelvin–Helmholtz instability associated with the vertical oscillations and that eventually produces horizontal structures. Contrary to other configurations in which the longitudinal axis of the prominence is permeated by a perpendicular magnetic field, like in unsheared arcades, the orientation of the prominence along the flux rope axis prevents the development of Rayleigh–Taylor instabilities and therefore the appearance of vertical structuring along this axis.

Laser spectroscopy with an electrostatic ConeTrap

Energy Technology Data Exchange (ETDEWEB)

Kelly, S., E-mail: sam.kelly@postgrad.manchester.ac.uk; Campbell, P. [University of Manchester, Nuclear Physics Group, Schuster Laboratory, Brunswick Street (United Kingdom); Cheal, B., E-mail: Bradley.Cheal@Liverpool.ac.uk [University of Liverpool, Oliver Lodge Laboratory (United Kingdom); Eronen, T.; Geldhof, S.; Jokinen, A.; Moore, I. D.; Penttilä, H.; Pohjalainen, I.; Rinta-Antila, S.; Sonnenschein, V.; Voss, A. [JYFL, University of Jyväskylä (Finland)

2017-11-15

A compact electrostatic trap has been designed and installed as part of the recent upgrades to the IGISOL IV facility. The ConeTrap provides an in vacuo optical pumping site for low energy (800 eV) ionic ensembles available for interaction periods of 10-100 ms. At present, 6.7(3) % of injected mass A=98 ions can be trapped, stored for 5 ms, extracted and transported to a laser-ion interaction region. This fraction represents those ions for which no perturbation to total energy or energy spread is observed. Proposed enhancements to the trap are designed to improve the trapping efficiency by up to a factor of 5. Differential pumping and reduction in background pressure below the present 10{sup −6} mbar will extend storage times beyond 100 ms.

Trapped surfaces in spherical stars

International Nuclear Information System (INIS)

Bizon, P.; Malec, E.; O'Murchadha, N.

1988-01-01

We give necessary and sufficient conditions for the existence of trapped surfaces in spherically symmetric spacetimes. These conditions show that the formation of trapped surfaces depends on both the degree of concentration and the average flow of the matter. The result can be considered as a partial validation of the cosmic-censorship hypothesis

Magnetic field re-arrangement after prominence eruption

International Nuclear Information System (INIS)

Kopp, R.A.; Poletto, G.

1986-01-01

It has long been known that magnetic reconnection plays a fundamental role in a variety of solar events. Although mainly invoked in flare problems, large-scale loops interconnecting active regions, evolving coronal hole boundaries, the solar magnetic cycle itself, provide different evidence of phenomena which involve magnetic reconnection. A further example might be given by the magnetic field rearrangement which occurs after the eruption of a prominence. Since most often a prominence reforms after its disappearance and may be observed at about the same position it occupied before erupting, the magnetic field has to undergo a temporary disruption to relax back, via reconnection, to a configuration similar to the previous one. The above sequence of events is best observable in the case of two-ribbon (2-R) flares but most probably is associated with all filament eruptions. Even if the explanation of the magnetic field rearrangement after 2-R flares in terms of reconnection is generally accepted, the lack of a three-dimensional model capable of describing the field reconfiguration, has prevented, up to now, a thorough analysis of its topology as traced by Hα/x-ray loops. The purpose of the present work is to present a numerical technique which enables one to predict and visualize the reconnected configuration, at any time t, and therefore allows one to make a significant comparison of observations and model predictions throughout the whole process. 5 refs., 3 figs

Quantum information processing with trapped ions

International Nuclear Information System (INIS)

Haeffner, H.; Haensel, W.; Rapol, U.; Koerber, T.; Benhelm, J.; Riebe, M.; Chek-al-Kar, D.; Schmidt-Kaler, F.; Becher, C.; Roos, C.; Blatt, R.

2005-01-01

Single Ca + ions and crystals of Ca + ions are confined in a linear Paul trap and are investigated for quantum information processing. Here we report on recent experimental advancements towards a quantum computer with such a system. Laser-cooled trapped ions are ideally suited systems for the investigation and implementation of quantum information processing as one can gain almost complete control over their internal and external degrees of freedom. The combination of a Paul type ion trap with laser cooling leads to unique properties of trapped cold ions, such as control of the motional state down to the zero-point of the trapping potential, a high degree of isolation from the environment and thus a very long time available for manipulations and interactions at the quantum level. The very same properties make single trapped atoms and ions well suited for storing quantum information in long lived internal states, e.g. by encoding a quantum bit (qubit) of information within the coherent superposition of the S 1/2 ground state and the metastable D 5/2 excited state of Ca + . Recently we have achieved the implementation of simple algorithms with up to 3 qubits on an ion-trap quantum computer. We will report on methods to implement single qubit rotations, the realization of a two-qubit universal quantum gate (Cirac-Zoller CNOT-gate), the deterministic generation of multi-particle entangled states (GHZ- and W-states), their full tomographic reconstruction, the realization of deterministic quantum teleportation, its quantum process tomography and the encoding of quantum information in decoherence-free subspaces with coherence times exceeding 20 seconds. (author)

Alberta's air quality index : facts at your fingertip

International Nuclear Information System (INIS)

2003-06-01

Alberta Environment measures the airborne concentrations of carbon dioxide, fine particulate matter, nitrogen dioxide, ozone and sulphur dioxide on a continuous basis at air quality monitoring stations in Edmonton, Calgary, Red Deer and Beaverlodge. Every hour, the readings are converted to an Air Quality Index (AQI) number to report on Alberta's outdoor air quality as either good, fair, poor or very poor. The categories relate to guidelines under Alberta's Environmental Protection and Enhancement Act and reflect the maximum acceptable levels specified by the National Ambient Air Quality Objectives. Current air quality conditions are available to the public through Alberta Environment's web site or by phoning a toll free number. Both Edmonton and Calgary report good air quality at least 90 per cent of the time. Occasionally, air quality in the two cities may reach the fair category, but it is seldom poor. Fair, poor or very poor air quality occurs with strong temperature inversion and light winds. Under these conditions, air pollutants, usually from automobiles, are trapped in a layer of stagnant air. Fair and poor air quality can also be caused by summer heat when photochemical smog forms by chemical reactions with oxides of nitrogen and volatile hydrocarbons. 1 ref., 1 tab., 1 fig

The Use of Camera Traps in Wildlife

Directory of Open Access Journals (Sweden)

Yasin Uçarlı

2013-11-01

Full Text Available Camera traps are increasingly used in the abundance and density estimates of wildlife species. Camera traps are very good alternative for direct observation in case, particularly, steep terrain, dense vegetation covered areas or nocturnal species. The main reason for the use of camera traps is eliminated that the economic, personnel and time loss in a continuous manner at the same time in different points. Camera traps, motion and heat sensitive, can take a photo or video according to the models. Crossover points and feeding or mating areas of the focal species are addressed as a priority camera trap set locations. The population size can be finding out by the images combined with Capture-Recapture methods. The population density came out the population size divided to effective sampling area size. Mating and breeding season, habitat choice, group structures and survival rates of the focal species can be achieved from the images. Camera traps are very useful to obtain the necessary data about the particularly mysterious species with economically in planning and conservation efforts.

Tightly confined atoms in optical dipole traps

International Nuclear Information System (INIS)

Schulz, M.

2002-12-01

This thesis reports on the design and setup of a new atom trap apparatus, which is developed to confine few rubidium atoms in ultrahigh vacuum and make them available for controlled manipulations. To maintain low background pressure, atoms of a vapour cell are transferred into a cold atomic beam by laser cooling techniques, and accumulated by a magneto-optic trap (MOT) in a separate part of the vacuum system. The laser cooled atoms are then transferred into dipole traps made of focused far-off-resonant laser fields in single- or crossed-beam geometry, which are superimposed with the center of the MOT. Gaussian as well as hollow Laguerre-Gaussian (LG$ ( 01)$) beam profiles are used with red-detuned or blue-detuned light, respectively. Microfabricated dielectric phase objects allow efficient and robust mode conversion of Gaussian into Laguerre-Gaussian laser beams. Trap geometries can easily be changed due to the highly flexible experimental setup. The dipole trap laser beams are focused to below 10 microns at a power of several hundred milliwatts. Typical trap parameters, at a detuning of several ten nanometers from the atomic resonance, are trag depths of few millikelvin, trap frequencies near 30-kHz, trap light scattering rates of few hundred photons per atom and second, and lifetimes of several seconds. The number of dipole-trapped atoms ranges from more than ten thousand to below ten. The dipole-trapped atoms are detected either by a photon counting system with very efficient straylight discrimination, or by recapture into the MOT, which is imaged onto a sensitive photodiode and a CCD-camera. Due to the strong AC-Stark shift imposed by the high intensity trapping light, energy-selective resonant excitation and detection of the atoms is possible. The measured energy distribution is consistent with a harmonic potential shape and allows the determination of temperatures and heating rates. In first measurements, the thermal energy is found to be about 10 % of the

Parameter Screening in Microfluidics Based Hydrodynamic Single-Cell Trapping

Directory of Open Access Journals (Sweden)

B. Deng

2014-01-01

Full Text Available Microfluidic cell-based arraying technology is widely used in the field of single-cell analysis. However, among developed devices, there is a compromise between cellular loading efficiencies and trapped cell densities, which deserves further analysis and optimization. To address this issue, the cell trapping efficiency of a microfluidic device with two parallel micro channels interconnected with cellular trapping sites was studied in this paper. By regulating channel inlet and outlet status, the microfluidic trapping structure can mimic key functioning units of previously reported devices. Numerical simulations were used to model this cellular trapping structure, quantifying the effects of channel on/off status and trapping structure geometries on the cellular trapping efficiency. Furthermore, the microfluidic device was fabricated based on conventional microfabrication and the cellular trapping efficiency was quantified in experiments. Experimental results showed that, besides geometry parameters, cellular travelling velocities and sizes also affected the single-cell trapping efficiency. By fine tuning parameters, more than 95% of trapping sites were taken by individual cells. This study may lay foundation in further studies of single-cell positioning in microfluidics and push forward the study of single-cell analysis.

Trapping guidelines for area-wide fruit fly programmes

International Nuclear Information System (INIS)

2003-11-01

Different traps and lures have been developed and used over decades to survey fruit fly populations. The first attractant for male fruit flies was methyl eugenol (ME) (for Bactrocera zonata, Howlett, 1912) followed by kerosene for Mediterranean fruit fly, Ceratitis capitata, (medfly), Severin and Severin, 1913. In 1956, Angelica seed oil was used to trap medfly (Steiner et al, 1957). Beroza et al. (1961) discovered trimedlure (TML) to be effective for the same purpose. Beroza and Green, 1963, demonstrated cuelure to be an effective attractant for Bactrocera cucurbitae. Food baits based on protein solutions, fermenting sugar solutions, fruit juices, and vinegar have been used since 1918 for the capture of females of several species. The McPhail trap was the first device to be used with protein baits (McPhail, 1929). Steiner traps were developed in 1957 (Steiner et al., 1957) and Jackson traps in 1971 for TML (Harris et al., 1971). These traps are currently used in various countries for fruit fly surveys in support of control activities and eradication campaigns. The combination of a McPhail trap with a protein attractant, Jackson trap with TML, and the Steiner trap with ME or cuelure (CUE), has remained unchanged for several decades. Global trends in increasing food quality, revenue sources, and fruit and vegetable trade, has resulted in an increased worldwide movement of fruit fly species and requires refinement of survey systems. After years of validating trapping technology through coordinated research programmes (CRP's) and extensive technical assistance to member countries, the Joint Division FAO/IAEA proposes the use of proven technologies in improving trap sensitivity in area-wide fruit fly control programmes (IAEA 1996 and IAEA 1998). These proven technologies include the use of synthetic food lures such as female attractants that can be used for several species of Anastrepha, Bactrocera and Ceratitis. Other citations of information on these developments are

Trapping guidelines for area-wide fruit fly programmes

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-11-01

Different traps and lures have been developed and used over decades to survey fruit fly populations. The first attractant for male fruit flies was methyl eugenol (ME) (for Bactrocera zonata, Howlett, 1912) followed by kerosene for Mediterranean fruit fly, Ceratitis capitata, (medfly), Severin and Severin, 1913. In 1956, Angelica seed oil was used to trap medfly (Steiner et al, 1957). Beroza et al. (1961) discovered trimedlure (TML) to be effective for the same purpose. Beroza and Green, 1963, demonstrated cuelure to be an effective attractant for Bactrocera cucurbitae. Food baits based on protein solutions, fermenting sugar solutions, fruit juices, and vinegar have been used since 1918 for the capture of females of several species. The McPhail trap was the first device to be used with protein baits (McPhail, 1929). Steiner traps were developed in 1957 (Steiner et al., 1957) and Jackson traps in 1971 for TML (Harris et al., 1971). These traps are currently used in various countries for fruit fly surveys in support of control activities and eradication campaigns. The combination of a McPhail trap with a protein attractant, Jackson trap with TML, and the Steiner trap with ME or cuelure (CUE), has remained unchanged for several decades. Global trends in increasing food quality, revenue sources, and fruit and vegetable trade, has resulted in an increased worldwide movement of fruit fly species and requires refinement of survey systems. After years of validating trapping technology through coordinated research programmes (CRP's) and extensive technical assistance to member countries, the Joint Division FAO/IAEA proposes the use of proven technologies in improving trap sensitivity in area-wide fruit fly control programmes (IAEA 1996 and IAEA 1998). These proven technologies include the use of synthetic food lures such as female attractants that can be used for several species of Anastrepha, Bactrocera and Ceratitis. Other citations of information on these developments are

On-chip particle trapping and manipulation

Science.gov (United States)

Leake, Kaelyn Danielle

The ability to control and manipulate the world around us is human nature. Humans and our ancestors have used tools for millions of years. Only in recent years have we been able to control objects at such small levels. In order to understand the world around us it is frequently necessary to interact with the biological world. Optical trapping and manipulation offer a non-invasive way to move, sort and interact with particles and cells to see how they react to the world around them. Optical tweezers are ideal in their abilities but they require large, non-portable, and expensive setups limiting how and where we can use them. A cheap portable platform is required in order to have optical manipulation reach its full potential. On-chip technology offers a great solution to this challenge. We focused on the Liquid-Core Anti-Resonant Reflecting Optical Waveguide (liquid-core ARROW) for our work. The ARROW is an ideal platform, which has anti-resonant layers which allow light to be guided in liquids, allowing for particles to easily be manipulated. It is manufactured using standard silicon manufacturing techniques making it easy to produce. The planner design makes it easy to integrate with other technologies. Initially I worked to improve the ARROW chip by reducing the intersection losses and by reducing the fluorescence and background on the ARROW chip. The ARROW chip has already been used to trap and push particles along its channel but here I introduce several new methods of particle trapping and manipulation on the ARROW chip. Traditional two beam traps use two counter propagating beams. A trapping scheme that uses two orthogonal beams which counter to first instinct allow for trapping at their intersection is introduced. This scheme is thoroughly predicted and analyzed using realistic conditions. Simulations of this method were done using a program which looks at both the fluidics and optical sources to model complex situations. These simulations were also used to

Quantized motion of trapped ions

International Nuclear Information System (INIS)

Steinbach, J.

1999-01-01

This thesis is concerned with a theoretical and numerical study of the preparation and coherent manipulation of quantum states in the external and internal degrees of freedom of trapped ions. In its first part, this thesis proposes and investigates schemes for generating several nonclassical states for the quantized vibrational motion of a trapped ion. Based on dark state preparation specific laser excitation configurations are presented which, given appropriately chosen initial states, realize the desired motional states in the steady-state, indicated by the cessation of the fluorescence emitted by the ion. The focus is on the SU(1,1) intelligent states in both their single- and two-mode realization, corresponding to one- and two-dimensional motion of the ion. The presented schemes are also studied numerically using a Monte-Carlo state-vector method. The second part of the thesis describes how two vibrational degrees of freedom of a single trapped ion can be coupled through the action of suitably chosen laser excitation. Concentrating on a two-dimensional ion trap with dissimilar vibrational frequencies a variety of quantized two-mode couplings are derived. The focus is on a linear coupling that takes excitations from one mode to another. It is demonstrated how this can result in a state rotation, in which it is possible to coherently transfer the motional state of the ion between orthogonal directions without prior knowledge of that motional state. The third part of this thesis presents a new efficient method for generating maximally entangled internal states of a collection of trapped ions. The method is deterministic and independent of the number of ions in the trap. As the essential element of the scheme a mechanism for the realization of a controlled NOT operation that can operate on multiple ions is proposed. The potential application of the scheme for high-precision frequency standards is explored. (author)

A quasi-electrostatic trap for neutral atoms

International Nuclear Information System (INIS)

Engler, H.

2000-01-01

This thesis reports on the realization of a ''quasi-electrostatic trap'' (QUEST) for neutral atoms. Cesium ( 133 Cs) and Lithium ( 7 Li) atoms are stored, which represents for the first time a mixture of different species in an optical dipole trap. The trap is formed by the focused Gaussian beam of a 30 W cw CO 2 -laser. For a beam waist of 108 μm the resulting trap depth is κ B x 118 μK for Cesium and κ B x 48 μK for Lithium. We transfer up to 2 x 10 6 Cesium and 10 5 Lithium atoms from a magneto-optical trap into the QUEST. When simultaneously transferred, the atom number currently is reduced by roughly a factor of 10. Since photon scattering from the trapping light can be neglected, the QUEST represents an almost perfect conservative trapping potential. Atoms in the QUEST populate the electronic ground state sublevels. Arbitrary sublevels can be addressed via optical pumping. Due to the very low background gas pressure of 2 x 10 -11 mbar storage times of several minutes are realized. Evaporative cooling of Cesium is observed. In addition, laser cooling is applied to the trapped Cesium sample, which reduces the temperature from 25 μK to a value below 7 μK. If prepared in the upper hyper-fine ground state sublevel, spin changing collisions are observed not only within one single species, but also between the two different species. The corresponding relaxation rates are quantitatively analyzed. (orig.)

External meeting - Geneva University: A lab in a trap: quantum gases in optical lattices

CERN Multimedia

2007-01-01

GENEVA UNIVERSITY ECOLE DE PHYSIQUE Département de physique nucléaire et corspusculaire 24, Quai Ernest-Ansermet 1211 GENEVE 4 - Tél: 022 379 62 73 - Fax: 022 379 69 92 Monday 16 April 2007 PARTICLE PHYSICS SEMINAR at 17:00 - Stückelberg Auditorium A lab in a trap: quantum gases in optical lattices by Prof. Tilman Esslinger / Department of Physics, ETH Zurich The field of ultra cold quantum gases has seen an astonishing development during the last ten years. With the demonstration of Bose-Einstein condensation in weakly interacting atomic gases a theoretical concept of unique beauty could be witnessed experimentally. Very recent developments have now made it possible to engineer atomic many-body systems which are dominated by strong interactions. A major driving force for these advances are experiments in which ultracold atoms are trapped in optical lattices. These systems provide anew avenue for designing and studying quantum many-body systems. Exposed to the crystal structure of interfering laser wave...

Time and financial costs of programs for live trapping feral cats.

Science.gov (United States)

Nutter, Felicia B; Stoskopf, Michael K; Levine, Jay F

2004-11-01

To determine the time and financial costs of programs for live trapping feral cats and determine whether allowing cats to become acclimated to the traps improved trapping effectiveness. Prospective cohort study. 107 feral cats in 9 colonies. 15 traps were set at each colony for 5 consecutive nights, and 5 traps were then set per night until trapping was complete. In 4 colonies, traps were immediately baited and set; in the remaining 5 colonies, traps were left open and cats were fed in the traps for 3 days prior to the initiation of trapping. Costs for bait and labor were calculated, and trapping effort and efficiency were assessed. Mean +/- SD overall trapping effort (ie, number of trap-nights until at least 90% of the cats in the colony had been captured or until no more than 1 cat remained untrapped) was 8.9 +/- 3.9 trap-nights per cat captured. Mean overall trapping efficiency (ie, percentage of cats captured per colony) was 98.0 +/- 4.0%. There were no significant differences in trapping effort or efficiency between colonies that were provided an acclimation period and colonies that were not. Overall trapping costs were significantly higher for colonies provided an acclimation period. Results suggest that these live-trapping protocols were effective. Feeding cats their regular diets in the traps for 3 days prior to the initiation of trapping did not have a significant effect on trapping effort or efficiency in the present study but was associated with significant increases in trapping costs.

Evaluation of Sediment Trap Efficiency in an Estuarine Environment

National Research Council Canada - National Science Library

Stoddard, Daniel

2001-01-01

.... A second trap of same dimensions was also incorporated 420 m upstream. Trap efficiency was calculated as a sediment removal ratio, or the percentage by which influent sediment load to the trap is reduced in the effluent load from the trap...

A purge-and-trap capillary column gas chromatographic method for the measurement of halocarbons in water and air

Energy Technology Data Exchange (ETDEWEB)

Happell, J.D.; Wallace, D.W.R.; Wills, K.D.; Wilke, R.J.; Neill, C.C.

1996-06-01

This report describes an automated, accurate, precise and sensitive capillary column purge- and -trap method capable of quantifying CFC-12, CFC-11, CFC-113, CH{sub 3}CCL{sub 3}, and CCL{sub 4} during a single chromatographic analysis in either water or gas phase samples.

Health effects from indoor air pollution: case studies.

Science.gov (United States)

White, L E; Clarkson, J R; Chang, S N

1987-01-01

In recent years there has been a growing awareness of the health effects associated with the presence of contaminants in indoor air. Numerous agents can accumulate in public buildings, homes and automobiles as a result of ongoing activities that normally occur in these closed spaces. Ventilation is a major factor in the control of indoor air pollutants since proper movement of air can prevent or minimize the build up of compounds in buildings. The recent emphasis on energy conservation has lead to measures which economize on energy for heating and air conditioning, but which also trap pollutants within a building. Three cases of indoor air pollution were investigated. A typical investigation of indoor air pollutant problems includes the following: interviews with building occupants; history of the building with regard to maintenance, pesticide treatment, etc.; a survey of the building and ventilation; and when warranted, sampling and analysis of air. Each case presented is unique in that atypical situations caused agents to accumulate in a building or section of a building. The indoor air problems in these cases were solved by identifying and removing the source of the offending agent and/or improving the ventilation in the building.

Acute neurological symptoms during hypobaric exposure: consider cerebral air embolism.

Science.gov (United States)

Weenink, Robert P; Hollmann, Markus W; van Hulst, Robert A

2012-11-01

Cerebral arterial gas embolism (CAGE) is well known as a complication of invasive medical procedures and as a risk in diving and submarine escape. In the underwater environment, CAGE is caused by trapped air, which expands and leads to lung vessel rupture when ambient pressure decreases during ascent. Pressure decrease also occurs during hypobaric activities such as flying and, therefore, CAGE may theoretically be a risk in hypobaric exposure. We reviewed the available literature on this subject. Identified were 12 cases of CAGE due to hypobaric exposure. Based on these cases, we discuss pathophysiology, diagnosis, and treatment of CAGE due to hypobaric exposure. The low and slow pressure decrease during most hypobaric activities (as opposed to diving) account for the low incidence of CAGE during these exposures and suggest that severe air trapping must be present to cause barotrauma. This is also suggested by the large prevalence of air filled cysts in the case reports reviewed. We recommend considering CAGE in all patients presenting with acute central neurological injury during or shortly after pressure decrease such as flying. A CT scan of head and chest should be performed in these patients. Treatment with hyperbaric oxygen therapy should be initiated as soon as possible in cases of proven or probable CAGE.

Dexterous ultrasonic levitation of millimeter-sized objects in air.

Science.gov (United States)

Seah, Sue Ann; Drinkwater, Bruce W; Carter, Tom; Malkin, Rob; Subramanian, Sriram

2014-07-01

Acoustic levitation in air has applications in contactless handling and processing. Here a first-order Bessel function-shaped acoustic field, generated using an 8-element circular array operating at 40 kHz, traps millimeter-sized objects against gravity. The device can manipulate objects in a vertical plane over a few millimeters with an accuracy of ± 0.09 mm.

Quantum computing with trapped ions

Energy Technology Data Exchange (ETDEWEB)

Hughes, R.J.

1998-01-01

The significance of quantum computation for cryptography is discussed. Following a brief survey of the requirements for quantum computational hardware, an overview of the ion trap quantum computation project at Los Alamos is presented. The physical limitations to quantum computation with trapped ions are analyzed and an assessment of the computational potential of the technology is made.

An Open Standard for Camera Trap Data

Directory of Open Access Journals (Sweden)

Tavis Forrester

2016-12-01

Full Text Available Camera traps that capture photos of animals are a valuable tool for monitoring biodiversity. The use of camera traps is rapidly increasing and there is an urgent need for standardization to facilitate data management, reporting and data sharing. Here we offer the Camera Trap Metadata Standard as an open data standard for storing and sharing camera trap data, developed by experts from a variety of organizations. The standard captures information necessary to share data between projects and offers a foundation for collecting the more detailed data needed for advanced analysis. The data standard captures information about study design, the type of camera used, and the location and species names for all detections in a standardized way. This information is critical for accurately assessing results from individual camera trapping projects and for combining data from multiple studies for meta-analysis. This data standard is an important step in aligning camera trapping surveys with best practices in data-intensive science. Ecology is moving rapidly into the realm of big data, and central data repositories are becoming a critical tool and are emerging for camera trap data. This data standard will help researchers standardize data terms, align past data to new repositories, and provide a framework for utilizing data across repositories and research projects to advance animal ecology and conservation.

Residual CO2 trapping in Indiana limestone.

Science.gov (United States)

El-Maghraby, Rehab M; Blunt, Martin J

2013-01-02

We performed core flooding experiments on Indiana limestone using the porous plate method to measure the amount of trapped CO(2) at a temperature of 50 °C and two pressures: 4.2 and 9 MPa. Brine was mixed with CO(2) for equilibration, then the mixture was circulated through a sacrificial core. Porosity and permeability tests conducted before and after 884 h of continuous core flooding confirmed negligible dissolution. A trapping curve for supercritical (sc)CO(2) in Indiana showing the relationship between the initial and residual CO(2) saturations was measured and compared with that of gaseous CO(2). The results were also compared with scCO(2) trapping in Berea sandstone at the same conditions. A scCO(2) residual trapping end point of 23.7% was observed, indicating slightly less trapping of scCO(2) in Indiana carbonates than in Berea sandstone. There is less trapping for gaseous CO(2) (end point of 18.8%). The system appears to be more water-wet under scCO(2) conditions, which is different from the trend observed in Berea; we hypothesize that this is due to the greater concentration of Ca(2+) in brine at higher pressure. Our work indicates that capillary trapping could contribute to the immobilization of CO(2) in carbonate aquifers.

Traffic-related air pollution and allergic disease: an update in the context of global urbanization.

Science.gov (United States)

Carlsten, Christopher; Rider, Christopher F

2017-04-01

The review aims to give an update on the literature around traffic-related air pollution (TRAP) and allergic disease in the context of global urbanization, as the most populous countries in the world face severe TRAP exposure challenges. As research continues to show that gene-environment interactions and epigenetics contribute to the TRAP-allergy link, evidence around the links to climate change grows. Greenspace may provide a buffer to adverse effects of traffic on health, overall, but pose risks in terms of allergic disease. The link between traffic-related pollution and allergy continues to strengthen, in terms of supportive observational findings and mechanistic studies. Levels of TRAP across the world, particularly in Asia, continue to dramatically exceed acceptable levels, suggesting that the related adverse health consequences will accelerate. This could be counterbalanced by primary emission control and urban planning. Attention to combined effects of TRAP and allergen exposure is critical to avoiding misleading inferences drawn though examination only of isolated factors.

HPLC-ESR techniques for detection of complex trapped radicals

International Nuclear Information System (INIS)

Tu Tiecheng; Dong Jirong; Lin Nianyun; Xie Leidong; Liu Rengzhong

1992-01-01

High performance liquid chromatography (HPLC) and ESR combined examination of radical species is an advanced techniques for separation and identification of complex radical species. At SRCL, Waters 990 HPLC has been used to separate the complex trapped radicals and Varian E-112 ESR spectrometer to record the spectra of single trapped radicals after HPLC separation. The advantages of the combined techniques are described as bellow: HPLC is used to separate the long-lived complex trapped radicals derived from reaction of short-lived radicals with spin trap. ESR spectra from single trapped radicals, obtained following HPLC separation of complex trapped radicals, are recorded one by one and well resolved. The structures of short-lived radicals can be inferred from the ESR spectra of the long-lived trapped radicals

Modification of a Pollen Trap Design To Capture Airborne Conidia of Entomophaga maimaiga and Detection of Conidia by Quantitative PCR.

Science.gov (United States)

Bittner, Tonya D; Hajek, Ann E; Liebhold, Andrew M; Thistle, Harold

2017-09-01

The goal of this study was to develop effective and practical field sampling methods for quantification of aerial deposition of airborne conidia of Entomophaga maimaiga over space and time. This important fungal pathogen is a major cause of larval death in invasive gypsy moth ( Lymantria dispar ) populations in the United States. Airborne conidia of this pathogen are relatively large (similar in size to pollen), with unusual characteristics, and require specialized methods for collection and quantification. Initially, dry sampling (settling of spores from the air onto a dry surface) was used to confirm the detectability of E. maimaiga at field sites with L. dispar deaths caused by E. maimaiga , using quantitative PCR (qPCR) methods. We then measured the signal degradation of conidial DNA on dry surfaces under field conditions, ultimately rejecting dry sampling as a reliable method due to rapid DNA degradation. We modified a chamber-style trap commonly used in palynology to capture settling spores in buffer. We tested this wet-trapping method in a large-scale (137-km) spore-trapping survey across gypsy moth outbreak regions in Pennsylvania undergoing epizootics, in the summer of 2016. Using 4-day collection periods during the period of late instar and pupal development, we detected variable amounts of target DNA settling from the air. The amounts declined over the season and with distance from the nearest defoliated area, indicating airborne spore dispersal from outbreak areas. IMPORTANCE We report on a method for trapping and quantifying airborne spores of Entomophaga maimaiga , an important fungal pathogen affecting gypsy moth ( Lymantria dispar ) populations. This method can be used to track dispersal of E. maimaiga from epizootic areas and ultimately to provide critical understanding of the spatial dynamics of gypsy moth-pathogen interactions. Copyright © 2017 American Society for Microbiology.

Vaginal orgasm is more prevalent among women with a prominent tubercle of the upper lip.

Science.gov (United States)

Brody, Stuart; Costa, Rui Miguel

2011-10-01

Recent studies have uncovered multiple markers of vaginal orgasm history (unblocked pelvic movement during walking, less use of immature psychological defense mechanisms, greater urethrovaginal space). Other markers (perhaps of prenatal origin) even without obvious mechanistic roles in vaginal orgasm might exist, and a clinical observation led to the novel hypothesis that a prominent tubercle of the upper lip is such a marker. To examine the hypothesis that a prominent tubercle of the upper lip is associated specifically with greater likelihood of experiencing vaginal orgasm (orgasm elicited by penile-vaginal intercourse [PVI] without concurrent masturbation). Women (N = 258, predominantly Scottish) completed an online survey reporting their frequencies of various sexual activities and corresponding orgasms, age, and the prominence of the tubercle of their upper lip. Social desirability response bias was also assessed. Multivariate associations of lip tubercle prominence with vaginal orgasm (ever and past month consistency) and with orgasm by other means. RESULTS.: A prominent and sharply raised lip tubercle was associated with greater odds (odds ratio = 12.3) of ever having a vaginal orgasm, and also with greater past month vaginal orgasm consistency (an effect driven by the women who never had a vaginal orgasm), than less prominent lip tubercle categories. Lip tubercle was not associated with social desirability responding, or with orgasm triggered by masturbation during PVI, solitary or partner clitoral or vaginal masturbation, vibrator, or cunnilingus. The results are discussed in light of the unique nature of vaginal orgasm and the possibility of prenatal developmental influences. © 2011 International Society for Sexual Medicine.

Prominent cerebral veins on susceptibility-weighted imaging (SWI) in pulmonary embolism

Energy Technology Data Exchange (ETDEWEB)

Oeztoprak, Bilge [Cumhuriyet University School of Medicine, Department of Radiology, Sivas (Turkey)

2017-07-15

Clinical applications of susceptibility-weighted imaging (SWI) are increasing steadily. The aim of this study is to investigate the appearance of cerebral veins on SWI, which is very sensitive to the deoxyhaemoglobin level in vessels, in pulmonary embolism (PE). The cranial SWI images of 19 patients with PE and 22 controls from September 2013 through March 2016 were retrospectively examined for the presence of prominent cerebral veins. MRI findings were correlated with blood oxygen levels. 12 of 19 patients with PE had hypoxemia and SWI images of 11 of these hypoxemic patients depicted prominent cerebral veins in the form of increased number, diameter, and elongation. The mean PaO{sub 2} and SaO{sub 2} in these patients were 48.5 ± 9.1 mmHg and 75.2 ± 8.0 %, respectively. There was a significant correlation between the presence of prominent veins on SWI and hypoxemia (p < 0.05). Of the 7 patients with normal blood oxygen pressure and saturation, 1 also showed an augmented appearance of cerebral veins on SWI. In the presence of neurological symptoms suggestive of an intracranial pathology in patients with PE, a SWI added to the conventional MRI sequences may predict hypoxemia and exclude other intracranial pathologies. (orig.)

Investigation of two-frequency Paul traps for antihydrogen production

Energy Technology Data Exchange (ETDEWEB)

Leefer, Nathan; Krimmel, Kai, E-mail: kkrimmel@students.uni-mainz.de [Helmholtz-Institut Mainz (Germany); Bertsche, William [University of Manchester (United Kingdom); Budker, Dmitry [Helmholtz-Institut Mainz (Germany); Fajans, Joel [University of California at Berkeley, Department of Physics (United States); Folman, Ron [Ben-Gurion University of the Negev, Department of Physics (Israel); Häffner, Hartmut [University of California at Berkeley, Department of Physics (United States); Schmidt-Kaler, Ferdinand [Helmholtz-Institut Mainz (Germany)

2017-11-15

Radio-frequency (rf) Paul traps operated with multifrequency rf trapping potentials provide the ability to independently confine charged particle species with widely different charge-to-mass ratios. In particular, these traps may find use in the field of antihydrogen recombination, allowing antiproton and positron clouds to be trapped and confined in the same volume without the use of large superconducting magnets. We explore the stability regions of two-frequency Paul traps and perform numerical simulations of small samples of multispecies charged-particle mixtures of up to twelve particles that indicate the promise of these traps for antihydrogen recombination.

Neurotoxicity of traffic-related air pollution.

Science.gov (United States)

Costa, Lucio G; Cole, Toby B; Coburn, Jacki; Chang, Yu-Chi; Dao, Khoi; Roqué, Pamela J

2017-03-01

The central nervous system is emerging as an important target for adverse health effects of air pollution, where it may contribute to neurodevelopmental and neurodegenerative disorders. Air pollution comprises several components, including particulate matter (PM) and ultrafine particulate matter (UFPM), gases, organic compounds, and metals. An important source of ambient PM and UFPM is represented by traffic-related air pollution, primarily diesel exhaust (DE). Human epidemiological studies and controlled animal studies have shown that exposure to air pollution, and to traffic-related air pollution or DE in particular, may lead to neurotoxicity. In particular, air pollution is emerging as a possible etiological factor in neurodevelopmental (e.g. autism spectrum disorders) and neurodegenerative (e.g. Alzheimer's disease) disorders. The most prominent effects caused by air pollution in both humans and animals are oxidative stress and neuro-inflammation. Studies in mice acutely exposed to DE (250-300μg/m 3 for 6h) have shown microglia activation, increased lipid peroxidation, and neuro-inflammation in various brain regions, particularly the hippocampus and the olfactory bulb. An impairment of adult neurogenesis was also found. In most cases, the effects of DE were more pronounced in male mice, possibly because of lower antioxidant abilities due to lower expression of paraoxonase 2. Copyright © 2015 Elsevier B.V. All rights reserved.

Spectroscopy with trapped highly charged ions

International Nuclear Information System (INIS)

Beiersdorfer, Peter

2009-01-01

We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed; and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

Scaling ion traps for quantum computing

CSIR Research Space (South Africa)

Uys, H