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Sample records for eastern indo-asian collision

  1. New geological evidence of crustal thickening in the Gangdese block prior to the Indo-Asian collision

    Institute of Scientific and Technical Information of China (English)

    DING Lin; LAI Qingzhou

    2003-01-01

    Recent mapping in the Gangdese block has revealed many leucogranites that are similar to those in the High Himalaya. These leucogranites formed at ~140 Ma as indicated by monazite Th-Pb ion-microprobe dating and cooled at ~130 Ma as indicated by muscovite 40Ar/39Ar dating. In conjunction with previous structural and paleogeographic studies, the new data indicate that the Gangdese block underwent crustal thickening and associated exhumation during ~140-130 Ma. In this regard, the southern margin of Eurasia continent was comparable to the modern South American Altiplano-Puna plateau, the prime example of active ocean-continent subduction and associated thickened crust. Specifically, the early stages of crustal thickening and uplifting of the Gangdese block may result from subduction of the Neo-Tethyan Ocean. If the Tibetan Plateau would form by accretion of a series of blocks with thickened crust, an elevated topographic plateau similar to the Altiplano- Puna plateau had formed before collision between the Indian and Eurasian plates. Then the Tibetan Plateau would have quickly thickened, uplifted, and begun to extend soon after onset of the collision. Thus, the deformational mechanism of the Tibetan Plateau is not distributed shortening, but rather concentrating deformation within regions of thin crust between the accreted blocks.

  2. Tackling health literacy: adaptation of public hypertension educational materials for an Indo-Asian population in Canada

    Directory of Open Access Journals (Sweden)

    Mohan Sailesh

    2011-01-01

    Full Text Available Abstract Background Indo-Asians in Canada are at increased risk for cardiovascular diseases. There is a need for cultural and language specific educational materials relating to this risk. During this project we developed and field tested the acceptability of a hypertension public education pamphlet tailored to fit the needs of an at risk local Indo-Asian population, in Calgary, Alberta, Canada. Methods A community health board representing Calgary's Indo-Asian communities identified the culturally specific educational needs and language preferences of the local population. An adaptation of an existing English language Canadian Public Hypertension Recommendations pamphlet was created considering the literacy and translation challenges. The adapted pamphlet was translated into four Indo-Asian languages. The adapted pamphlets were disseminated as part of the initial educational component of a community-based culturally and language-sensitive cardiovascular risk factor screening and management program. Field testing of the materials was undertaken when participants returned for program follow-up seven to 12 months later. Results Fifty-nine English-speaking participants evaluated and confirmed the concept validity of the English adapted version. 28 non-English speaking participants evaluated the Gujarati (N = 13 and Punjabi (N = 15 translated versions of the adapted pamphlets. All participants found the pamphlets acceptable and felt they had improved their understanding of hypertension. Conclusions Involving the target community to identify health issues as well as help to create culturally, language and literacy sensitive health education materials ensures resources are highly acceptable to that community. Minor changes to the materials will be needed prior to formal testing of hypertension knowledge and health decision-making on a larger scale within this at risk community.

  3. Indian Ocean Experiment: An integrated analysis of the climate forcing and effects of the great Indo-Asian haze

    OpenAIRE

    2001-01-01

    Every year, from December to April, anthropogenic haze spreads over most of the North Indian Ocean, and South and Southeast Asia. The Indian Ocean Experiment (INDOEX) documented this Indo-Asian haze at scales ranging from individual particles to its contribution to the regional climate forcing. This study integrates the multiplatform observations (satellites, aircraft, ships, surface stations, and balloons) with one- and four-dimensional models to derive the regional aerosol forcing resulting...

  4. A comparison of cardiovascular risk factors among Indo-Asian and caucasian patients admitted with acute myocardial infarction in Kuala Lumpur, Malaysia and Birmingham, England.

    Science.gov (United States)

    Dhanjal, T S; Lal, M; Haynes, R; Lip, G

    2001-12-01

    Indo-Asians in the UK are at an increased risk of coronary artery disease (CAD); this may be a reflection of their cardiovascular risk factor profile as well as of a more sedentary lifestyle. We hypothesised that Indo-Asians in Malaysia and the UK may exhibit a similar cardiovascular risk factor and physical activity profile, which would be more adverse compared with caucasians. We studied 70 consecutive Indo-Asian patients admitted to hospitals in Kuala Lumpur, Malaysia (n=42; 35 males; mean age 60.6 years, SD 11.8); and Birmingham, England (n=28; 20 males; mean age 60.8 years, SD 12.9). Both groups of Indo-Asian patients were compared with 20 caucasian patients (13 males; mean age 62.7 years, SD 9.4) admitted with myocardial infarction from Birmingham. There was a higher prevalence of diabetes among Indo-Asians in both countries than among caucasians (p=0.0225). By contrast, caucasians had a higher prevalence of hypercholesterolaemia (p=0.0113), peripheral vascular disease (p=0.0008), regular alcohol consumption (pMalaysia and the UK, may in part contribute to the high incidence of CAD in this ethnic group.

  5. Bird collision impacts at wind turbines in eastern North America

    Energy Technology Data Exchange (ETDEWEB)

    Kerlinger, Paul; Curry, Richard; Guarnaccia, John [Curry and Kerlinger, LLC (United States)

    2011-07-01

    This paper discusses the incidence of bird collisions at wind turbines in Eastern North America. Modern wind turbines are high, with long, tubular towers. Bird fatality is analyzed and references to the relevant studies that have been done are given. 26 sites were investigated for turbine mortality in 2011 and these are shown on a map. 64 turbines were examined in Maple Ridge and it was seen that 4 birds were killed per turbine per year. The results demonstrated that no eagles were killed, there were no endangered species involved and there was no real deviation from site to site. More than 80,000 individual turbines were researched and more than $30 million spent on the study. Around 120,000 birds are killed per year, or an average of over 6 birds per turbine per year, in the United States. It is clear from the extensive research conducted that there are a lot of data on birds and turbines; the data show that songbirds are the most often affected.

  6. Magmatic evolution of the Early Pliocene Etrüsk stratovolcano, Eastern Anatolian Collision Zone, Turkey

    Science.gov (United States)

    Oyan, Vural; Keskin, Mehmet; Lebedev, Vladimir A.; Chugaev, Andrey V.; Sharkov, Evgenii V.

    2016-07-01

    The Pliocene Etrüsk stratovolcano, located in the northeast of Lake Van (Eastern Anatolia; Turkey), is one of the important volcanic centres in the Eastern Anatolian collision zone. Mt. Etrüsk overlies a widespread volcanic plateau, consisting of basaltic and hawaiitic lavas formed by fissure eruptions between 4.9-4.5 Ma. These basic lavas contain a phenocryst phase consisting of olivine, plagioclase and clinopyroxene. Trace element ratio diagrams imply that these basic magmas were generated from a mantle that contained a clear subduction component that is related to the subducted sediments rather than fluids or altered oceanic crust. Results of the melting models on the basaltic plateau lavas indicate that there was a marked variation both in the mantle source mineralogy (i.e. the ratio of garnet peridotite to spinel peridotite in the source varies between 60/40% and 40/60%) and the degree of melting (i.e. F between 0.8-4%). This can be explained by a model in which magmas were generated by partial melting of both metasomatised lithospheric and deeper asthenospheric mantle sources in an extensional setting in response to the partial delamination of the lithospheric mantle of Eastern Anatolia and then mixed with each other during Pliocene times. Central eruptions that formed the Etrüsk volcano lasted ~ 600 kyr between 4.3-3.7 Ma during Zanclean times. The estimated depth of the Etrüsk magma chamber is ~ 9-12 km. The volcano erupted lavas with a rather narrow compositional range from latite to rhyolite, which are either transitional or mildly alkaline in character. The Etrüsk lavas contain plagioclase, clino- and orthopyroxene, biotite, K-feldspar and rarely, minor amounts of olivine and amphibole in the phenocryst phase. A composite chemo-stratigraphic section of the volcano and petrological models indicate that the evolved lavas of the Etrüsk volcano differentiated from a parental magma composition, which is similar to that of the most primitive plateau

  7. Geodynamic and Magmatic Evolution of the Eastern Anatolian-Arabian Collision Zone, Turkey

    Science.gov (United States)

    Keskin, Mehmet

    2014-05-01

    The Eastern Anatolian-Arabian Collision Zone represents a crucial site within the Tethyan domain where a subduction system involving a volcanic arc (i.e. Cretaceous to Oligocene Pontide volcanic arc in the north) associated with a large subduction-accretion complex (i.e. Cretaceous to Oligocene Eastern Anatolian Accretionary Complex i.e. "EAAC" in the south) turned later into a major continental collision zone that experienced a series of geodynamic events including lithospheric delamination, slab-steepening & breakoff, regional domal uplift, widespread volcanism and tectonic escape via strike slip fault systems. The region includes some of the largest volcanic centers (e.g. Karacadaǧ, Aǧırkaya caldera, Ararat, Nemrut, Tendürek and Süphan volcanoes) and plateaus (e.g. The Erzurum-Kars Plateau) as well as the largest transform fault zones in the Mediterranean region. A recent geodynamic modeling study (Faccenna et al., 2013) has suggested that both the closure of the Tethys Ocean and the resultant collision were driven by a large scale and northerly directed asthenospheric mantle flow named the "Tethyan convection cell". This convection cell initiated around 25 Ma by combined effects of mantle upwelling of the Afar super plume located in the south, around 3,000 km away from the collision zone and the slab-pull of the Tethyan oceanic lithosphere beneath Anatolia in the north. The aforementioned mantle flow dragged Arabia to the north towards Eastern Anatolia with an average velocity of 2 cm/y for the last 20 My, twice as fast as the convergence of the African continent (i.e. 1 cm/y) with western and Central Turkey. This 1 cm/y difference resulted in the formation of the left lateral Dead Sea Strike Slip Fault between the African and Arabian plates. Not only did this mantle flow result in the formation of a positive dynamic topography in the west of Arabian block, but also created a dynamic tilting toward the Persian Gulf (Faccenna et al., 2013). Another

  8. Ages and tectonic significance of the collision-related granite porphyries in the Lhunzhub Basin,Tibet,China

    Institute of Scientific and Technical Information of China (English)

    WANG LiQuan; ZHU DiCheng; GENG QuanRu; LIAO ZhongLi; PAN GuiTang

    2007-01-01

    The Paleocene collision-related granite porphyries are identified for the first time along the western margin of the Lhunzhub Basin,Tibet.SHRIMP U-Pb zircon analysis indicates that the granite porphyries were emplaced at 58.7±1.1 Ma(MSWD=0.79)during the Indo-Asian continental collision.The granite porphyries are peraluminous and high in K,belonging to the calc-alkaline to high-K calc-alkaline series.They are relatively enriched in LILE,Th and LREE and depletion in Ba,Nb,P and Ti,characterized by LREE-enriched patterns with slightly to moderately negative Eu anomalies.These Paleocene granite porphyries are interpreted as the products generated by partial melting of the pre-existing arc crustal rocks caused by the increase of pressures and temperatures during the crustal shortening at the early stages of the Indo-Asian continental collision since 65 Ma.Despite inherited geochemical features and tectonic settings of the arc protoliths,they are significantly different from the volcanic rocks of the Dianzhong Formation within the Linzizong Group and the Miocene granite porphyries in the Gangdise belt.

  9. On the extent and significance of Oligocene mountain building in eastern Tibet (Invited)

    Science.gov (United States)

    Kirby, E.; Furlong, K. P.; Cook, K. L.; Ouimet, W. B.; Shi, X.; Wang, E.; Kamp, P. J.; Hodges, K. V.

    2013-12-01

    High topography in the region north and east of the Indo-Asian collision zone is typically considered to have developed in Miocene time, potentially in response to outward flow of weak lower crust from beneath the Tibetan Plateau. Much of the evidence for an increase in surface elevation in eastern Tibet is inferential and relies on the onset of rapid cooling and deep exhumation in the great river valleys along the plateau margin as recorded in low-temperature thermochronometers. Recently, detailed reconstruction of thermal/exhumational histories along the Longmen Shan, adjacent to the Sichuan Basin, reveals a pre-Miocene phase of mountain building (Wang et al., 2012). However, whether this event is confined to the Longmen Shan or whether it reflects widespread mountain building in the region remains unknown. Here, we synthesize emerging thermochronologic evidence from studies that utilize higher-temperature systems which are sensitive to deeper exhumation and that span various regions of the plateau margin. In the western Longmen Shan, late Oligocene - early Miocene zircon (U-Th)/He (zHe) ages from the summit of the Xuelongbao Massif (~5500m) require that mountain building was well underway along this margin by Oligocene time. In the Danba region, farther south, biotite and muscovite 40Ar/39Ar ages of samples from both fault zones and the surrounding rocks indicate that the faults were active at about 25- 30 Ma. Combined with structural and regional thermochronology data, this suggests that folding and exhumation of the Danba Anticlinorium began in mid-Tertiary time. Even farther south, along the Yalong River, biotite 40Ar/39Ar ages and zHe ages along an age-elevation transect reveal that the onset of rapid exhumation began around the same time, at ca. 30 Ma. Our results, in conjunction with existing data on the timing of deformation along the Aliao-Shan/Red River shear zone, implies that the onset of mountain building in eastern Tibet was widespread in late

  10. The Güira de Jauco amphibolite complex (eastern Cuba). A record of early Campanian collision in the Caribbean plate.

    Science.gov (United States)

    Lázaro, C.; Blanco-Quintero, I. F.; García-Casco, A.; Rojas--Agramonte, Y.; Corsini, M.; Núñez-Cambra, K.

    2012-04-01

    Petrological, geochemical and regional geological arguments suggest that the Güira de Jauco amphibolite complex (eastern Cuba) constitutes the metamorphic sole of the huge Cretaceous back-arc related Mayarí-Baracoa ophiolite belt and, hence, this complex is of major interest for deciphering the deficiently known intra-oceanic orogenic history of the Caribbean belt. The amphibolites have subalkaline low- to medium-K basaltic compositions. Chondrite-normalized REE patterns, ranging from flat LREE-depleted to slightly LREE-enriched patterns, and discrimination geochemical diagrams suggest N- to E-MORB protoliths. The peak mineral assemblages are formed by plagioclase (Xab=0.50-0.80), calcic amphibole (pargasite-edenite), titanite, ±epidote, ±quartz, ±diposide, ±garnet (Xalm = 0.45-0.48, Xgrs = 0.41-0.47), typical of epidote amphibolite facies. Retrograde albite, actinolite, clinozoisite, and chlorite record greenschist facies overprint. Peak P-T estimations are 650-750 °C and 7-10 kbar, corresponding to an apparent geothermal gradient of 25°C/km. 40Ar/39Ar step-heating dating of hornblende from three samples yielded ages of 76.6±2 Ma, 78.4±2 Ma and 80.7±7.5 Ma. These arguments, the strong syn-metamorphic deformation of the complex, and stratigraphic data of the eastern Cuba volcanic arc indicating lack of activity at (roughly) Mid-Campanian age indicate onset of collision and ophiolite obduction towards the NE in the back-arc environment of the region shortly before 80 Ma (early Campanian), i.e., more than 10 Myr before subduction/collision/accretion of platform- and arc-derived high-pressure metamorphic units took place in the leading edge of the Caribbean plate (Guatemala, Cuba and Dominican Republic) in response to arc-continent collision (from 70 Ma to Eocene). Such early Campanian age of onset of oceanic tectonic shortening can hardly be related to subduction/collision of the thick oceanic Caribbean lithosphere with the Caribbean arc, for no

  11. A revisit to the Higo terrane, Kyushu, Japan: The eastern extension of the North China-South China collision zone

    Science.gov (United States)

    Suga, Kenshi; Yui, Tzen-Fu; Miyazaki, Kazuhiro; Sakata, Shuhei; Hirata, Takafumi; Fukuyama, Mayuko

    2017-08-01

    The Higo and Manotani high-T metamorphic rocks belong to the Higo terrane, central Kyushu, Japan. This terrane has been suggested as the eastern extension of the North China-South China collision zone based mainly on the similar petrological and geochronological data to the north Dabie high-grade rocks. In this study, detrital zircon U-Pb dating for the Higo metamorphic rocks yielded a maximum depositional age of 197 Ma with a prominent component at 193-284 Ma (62-95%) and a subsidiary peak at 1847-1875 Ma (19-28%); whereas for the Manotani metamorphic rocks, the maximum depositional age is 263 Ma with a prominent component at 263-304 Ma (98%). These results suggest that the protoliths of the Higo and Manotani metamorphic rocks might be equivalent to those of the early-middle Jurassic Chizu and late Triassic Suo high-P metamorphic rocks, southwest Japan, respectively. The absence of middle Neoproterozoic detrital zircon (c. 700-825 Ma) is incompatible with a proposition that the proto-Japan might have been located close to the South China craton, where Permian-Jurassic sedimentary rocks contain a significant amount of middle Neoproterozoic detrital zircon. The zircon provenance of the Higo terrane, as well as of the Chizu and Suo belts, could therefore be the North China craton, suggesting that the Suo metamorphic rocks, including the Manotani metamorphic rocks, have formed at the subduction plate boundary in the east, which changed into the contemporaneous North China-South China collision plate boundary in the west, likely passing through the Korean Peninsula. The transformation of the Chizu and Suo metamorphic rocks to the Higo and Manotani metamorphic rocks can be accounted for by the oceanward advance of the volcanic arc during trench retreating. The Cretaceous high-T metamorphism and related igneous intrusions of the Higo terrane would be regarded as the initial phase of the Ryoke event.

  12. Mafic dykes at the southwestern margin of Eastern Ghats belt: Evidence of rifting and collision

    Indian Academy of Sciences (India)

    S Bhattacharya; A K Chaudhary; W Teixeira

    2010-12-01

    The southwestern margin of the Eastern Ghats Belt characteristically exposes ma fic dykes intruding massif-type charnockites. Dykes of olivine basalt of alkaline composition have characteristic trace element signatures comparable with Ocean Island Basalt (OIB). Most importantly strong positive Nb anomaly and low values of Zr/Nb ratio are consistent with OIB source of the mafic dykes. K –Ar isotopic data indicate two cooling ages at 740 and 530 Ma. The Pan-African thermal event could be related to reactivation of major shear zones and represented by leuco-granite vein along minor shear bands. And 740 Ma cooling age may indicate the low grade metamorphic imprints, noted in some of the dykes. Although no intrusion age could be determined from the present dataset, it could be constrained by some age data of the host charnockite gneiss and Alkaline rocks of the adjacent Prakasam Province. Assuming an intrusion age of ∼1 .3 Ga, Sr –Nd isotopic composition of the dykes indicate that they preserved time-integrated LREE enrichment. In view of the chemical signatures of OIB source, the ma fic dykes could as well be related to continental rifting, around 1.3 Ga, which may have been initiated by intra-plate volcanism.

  13. Thermomechanical consequences of Cretaceous continent-continent collision in the eastern Alps (Austria): Insights from two-dimensional modeling

    Science.gov (United States)

    Willingshofer, Ernst; van Wees, J. D.; Cloetingh, S. A. P. L.; Neubauer, F.

    1999-10-01

    We use two-dimensional numerical modeling techniques to investigate the thermomechanical consequences of closure of the Meliata-Hallstatt ocean and consequent Cretaceous continent-continent collision in the eastern Alps (Austria). In the modeling a lower plate position of the Austro-Alpine (AA) continental block is adopted during collision with the Upper Juvavic-Silice block. The thermal structure of the lithosphere was calculated for major AA tectonic units (Upper, Middle, and Lower Austro-Alpine) by integration of the transient heat flow equation along an approximately NW-SE cross section east of the Tauern Window. Indications of the rheological evolution of the AA were determined by calculating strength profiles at key stages of the Cretaceous orogeny, making use of the thermal modeling predictions combined with rock mechanics data. Cooling in the upper plate and lower greenschist facies metamorphism within footwall parts of the lower Upper Austro-Alpine (UA) plate, related to SE directed underthrusting of the UA beneath the Upper Juvavic-Silice block at circa 100 Ma, were predicted by the numerical model. The observed pressure-temperature path for deeply buried Middle Austro-Alpine (MA) upper crustal units and their subsequent isothermal exhumation are best reproduced assuming a pressure peak at 95 Ma and exhumation rates ranging between 4 and 7.5 mm yr-1. From the modeling results, we deduce that the temperature evolution during eclogite exhumation is primarily dependent on rates of tectonic movements and largely independent of the mode of exhumation (thrusting versus erosion). Furthermore, very rapid postmetamorphic exhumation of southern Lower Austro-Alpine (LA) units is predicted in order to account for subsequent cooling. This is constrained by 40Ar/39Ar data. The cooling paths of MA and LA rocks appear to be primarily controlled by their near-surface positions at the end of the Cretaceous rather than by other processes such as concurrent underthrusting

  14. Coeval doming and stretching of the eastern end of the India-Asia collision zone - Namche Barwa Syntaxis, Tibet

    Science.gov (United States)

    Scharf, A.; Handy, M. R.; Crupi, P.

    2013-12-01

    The eastern part of the India-Asia collisional zone is marked by a N-plunging, non-cylindrical fold, the Namche Barwa Syntaxis (NBS) with a topographic relief of >7 km. The NBS exposes rapidly exhuming Indian- and parts of the overlying Asian crust. Structural, paleomagnetic and GPS studies reveal clockwise rotation of the crust and mantle around a steep axis located close to the mutual borders of India, China and Myanmar (e.g. Sol et al. 2007; Liebke et al. 2011). Teleseismic tomography beneath the NBS reveals 170 km thick Indian lithosphere that is not connected with a slab anomaly to the N beneath the Tibetan Plateau, but that appears laterally continuous with north and E-dipping slab anomalies along strike of the Himalayan chain, respectively, to the W and E of the NBS (Zhang et al. 2012). A closer look at available structural, geochronological, and petrological data reveals Late Oligocene, N-directed subduction of Indian continental lithosphere followed by two stages of pronounced exhumation in Late Oligocene to Miocene time and unroofing in Pliocene time. This history is intimately related to the mantle structure imaged beneath the NBS. Timing of subduction is not constraint in the NBS, but Booth et al. (2009) suggest Palaeocene to Eocene ages for subduction-related plutonism along strike of the India/Asia suture zone. High-pressure (HP) conditions in granulites in the western NBS at 25-24 Ma preceded decompression beginning no later than 18 Ma (Su et al. 2012). These granulites are separated from granulites without HP assemblages by a moderately W-dipping mylonitic fault, indicating that this fault was a thrust (Xu et al. 2012) which accommodated S to E directed exhumation of the HP granulites in its hangingwall. This first stage of exhumation coincided with peak temperatures at ~10 Ma (Booth et al. 2009). The granulites and their intervening thrust fault are folded by the NBS (Geng et al. 2006), indicating that this first stage of exhumation preceded doming

  15. Rheology of the Indian and Tarim plates in the Karakoram continent-to-continent collision zone

    Directory of Open Access Journals (Sweden)

    A. Caporali

    1997-06-01

    Full Text Available Bouguer gravity anomalies in the region of Western Himalayas, Karakoram and Tien Shan show large negative values, but classical isostatic models are insufficient to account for the detailed pattern of the observed anomalies. In the past years the gravimetric surveys in the Karakoram done by Marussi, Caputo and others in 1954 have been extended and intensified. The full body of available gravimetric data, including the pendulum observations by De Filippi and Hedin at the beginning of this century, have been re-analyzed. Terrain corrections have been computed systematically for all available data using a unique algorithm and Digital Terrain Model. The isostatic anomalies along a profile from the Indo-Gangetic foredeep, across the Karakoram range and terminating in the Tarim basin show the oscillating values already noted by Marussi. It is here proposed that this oscillatory pattern can be explained by a model in which the convergent boundaries of the Indian and Tarim plates deform by elastic flexure, besides isostasy. The gravity data constrain the numerical values of the model parameters, particularly the flexural rigidity of the plates. For the Indian plate the best fitting value of the flexural rigidity is D = 5 1024 N m, a value very similar to those reported in Central Himalaya. The flexural rigidity of the Tarim plate turns out to be considerably larger D = 7 1025 N m, which makes the Tarim more rigid than the neighboring Central Tibet. Both plates are loaded by an estimated shear stress of 7 1012 N m-1 located in a region corresponding to the Nanga Parbat Haramosh syntaxis. It is concluded that the Indo-Asian continental collision in the Western Himalaya and Karakoram resulted in the development of flexural basins on both sides, unlike the Central Himalaya where the collision produced a flexural basin, the Ganga basin, to the south and, to the north, the indentation of an isostatically supported Tibetan block with possible rheological

  16. Multi-phase tectonic structures in the collision zone of the Kolyma-Omolon microcontinent and the eastern margin of the North Asian craton, Northeastern Russia

    OpenAIRE

    Prokopiev, A. V.; Oxman, V. S.

    2009-01-01

    The sequence of formation of structures is established in the zone of junction of the eastern margin of the North Asian craton and the northeastern flank of the Kolyma-Omolon microcontinent, in the area of bend of the Kolyma structural loop. Detailed structural studies revealed two phases in the formation of Mesozoic structures – an early thrust phase and a late strike-slip phase. Structures formed during each of the phases are described. Thrust structures are represented...

  17. Collision Event during 177-135 Ma on the Eastern Margin of the Qinghai-Tibet Plateau: Evidence from 40Ar/ 39Ar Dating for Basalts on the Western Margin of the Yangtze Platform

    Institute of Scientific and Technical Information of China (English)

    侯增谦; 陈文; 卢记仁

    2002-01-01

    Geochronology of continental flood basalts sampled from the Emei large igneous province (LIP) on the western margin of the Yangtze platform was investigated by the laser microprobe 40Ar/39Ar dating technique. These basalts yield a fairly wide range of 40Ar/39Ar ages, varying from 259 to 135 Ma. One basalt sample, at least altered, recorded the oldest 40Ar/39Ar age of about 259 Ma, corresponding to a peak eruption age of the Emei LIP continental flood basalts. Most of the samples yield much younger ages from 135 to 177 Ma, which are consistent with the K-Ar ages for the same samples (122.8-172.1 Ma). The dating data suggest that these Permian basalts had been widely affected by the regional tectonothermal event at 177-135 Ma. The event was probably caused by the convergence and collision among the Laurasia, Yangtze and Qiangtang-Qamdo continental blocks on the eastern margin of the Qinghai-Tibet plateau after the late Triassic. The age of the event reflects the timing of the peak collisional orogeny.

  18. Collision Mechanics

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Servis, D.P.; Zhang, Shengming;

    1999-01-01

    The first section of the present report describes the procedures that are being programmed at DTU for evaluation of the external collision dynamics. Then follows a detailed description of a comprehensive finite element analysis of one collision scenario for MS Dextra carried out at NTUA. The last...

  19. EASTERN UGANDA

    African Journals Online (AJOL)

    EVALUATION OF SELECTED ELITE POTATO GENOTYPES IN. EASTERN ... Significant

  20. Velocity and anisotropy structure of the uppermost mantle under the eastern Tibetan plateau inferred from Pn tomography%青藏高原东缘上地幔顶部Pn波速度结构及各向异性研究

    Institute of Scientific and Technical Information of China (English)

    黎源; 雷建设

    2012-01-01

    . Combining with the data from the observational bulletins of Chinese provincial seismic networks, we obtained a new model of seismic velocity and anisotropy of the uppermost mantle under the eastern Tibetan plateau. Our results show obvious lateral heterogeneities in the study region. The old basins and stable blocks,such as the Sichuan and Qaidam basins and Lhasa and Alashan blocks, show prominent high-velocity anomalies, while the Qilian-Qinling fold zone and northern Chuan-Dian diamond-shaped block exhibit relatively weaker high-velocity anomalies. A pronounced north-south trending low-velocity anomaly zone exists from the Songpan-Garze block east of the Longriba fault, southward through the Anning-Zemu fault zone to the southern Chuan-Dian diamond-shaped block. In the Sanjiang fold system, Burma-subduction zone and the region southeast of the Sichuan basin, there are three obvious low-velocity anomalies. Most of crustal major earthquakes occur on the edges of high-velocity anomalies or the transition zone from high to low velocities, suggesting that crustal earthquakes may be somewhat related to the mantle structure. The fast direction of Pn propagation around the eastern Himalayan syntaxis rotates in a clockwise manner, suggesting that it is related to the Indo-Asian collision. The fast direction changes sharply across the Longmenshan fault zone from NE under the Songpan-Garze block in the west to EW under the Sichuan basin in the east, implying that the material flow of the Tibetan plateau is divided into the NE and SW braches when it meets the Sichuan basin. To south of 26°N, in the Chuan-Dian region the Pn fast direction is in an approximate N-S direction, which is consistent with the GPS observations but different from SKS splitting results, suggesting the mechanically coupling of the crust and the uppermost mantle but decoupling at certain depths between the uppermost and lithospheric mantle.

  1. Paleotsunamis in Eastern Taiwan

    Science.gov (United States)

    Yen, Jiun-Yee; Yu, Neng-Ti; Hirakawa, Kazuomi; Chyi, Shyh-Jeng; Huang, Shao-Yi

    2017-04-01

    Although Taiwan is located in the active collision zone between Eurasian and the Philippine Sea plate with very high seismicity in and surrounding the island, and supposedly highly susceptible to tsunami hazard. However, there is no record of tsunami hazard in the past one hundred years, and only very few historical records show some possible extreme event occurred. Therefore study of tsunami was scarce in Taiwan. Although historical records do show possible tsunami events, the records were too sparse and incomplete to confidently reconstruct the paleotsunami events. In the past few years, numerical simulations based on possible tsunami-genic zones near Taiwan show that the island could be affected by the correctly directed tsunami. Nevertheless, there is no detail, scientific research of paleotsunami records yet in Taiwan. Our field survey in eastern Taiwan (facing the western Pacific Ocean) along the coast uncovered several outcrops contain gravels embedded in well-developed soil layers. The rounded meta-sandstone gravels are clearly beach-origin and were brought to their current location upon extreme wave events, which is composed of either volcanic-clastic deposits from nearby hills or organic soil layers formed locally. Our investigation indicates that there are at least 3 events in the northern half of eastern Taiwan and at least 2 events in southern part of eastern Taiwan. Although these outcrops are next to the shoreline and Taiwan is susceptible from typhoons, these gravels could be farther away from the beach at the time of their deposition due to current high retreat rate of the sea cliff. Further investigations are needed to delineate possible sources of tsunamis that caused the deposits.

  2. Early-Middle Paleozoic subduction-collision history of the south-eastern Central Asian Orogenic Belt: Evidence from igneous and metasedimentary rocks of central Jilin Province, NE China

    Science.gov (United States)

    Pei, Fu-Ping; Zhang, Ying; Wang, Zhi-Wei; Cao, Hua-Hua; Xu, Wen-Liang; Wang, Zi-Jin; Wang, Feng; Yang, Chuan

    2016-09-01

    To constrain the Early-Middle Paleozoic tectonic evolution of the south-eastern segment of the Central Asian Orogenic Belt (CAOB), we undertook zircon U-Pb dating and analyzed major and trace elements and zircon Hf isotope compositions of Late Cambrian to Middle Devonian igneous and metasedimentary rocks in central Jilin Province, NE China. LA-ICP-MS zircon U-Pb dating indicates that the Early-Middle Paleozoic magmatism in central Jilin Province can be divided into four episodes: Late Cambrian (ca. 493 Ma), Middle Ordovician (ca. 467 Ma), Late Ordovician-Early Silurian (ca. 443 Ma), and Late Silurian-Middle Devonian (425-396 Ma). The progression from subduction initiation to maturity is recorded by Late Cambrian low-K tholeiitic meta-diabase, Middle Ordovician medium-K calc-alkaline pyroxene andesite, and Late Ordovician to Early Silurian low-K tonalite, which all have subduction-related characteristics and formed in an evolving supra-subduction zone setting. Late Silurian to Middle Devonian calc-alkaline igneous rocks, with the lithological association of granodiorite, monzogranite, rhyolite, dacite, and trachydacite, show progressively increasing K2O contents from medium K to shoshonite series. Furthermore, the Early-Middle Devonian monzogranites are characterized by high K2O, Sr/Y, and [La/Yb]N values, indicating they were generated by the melting of thickened lower crust. These results suggest a transition from subduction to post-orogenic setting during the Late Silurian-Middle Devonian. Our interpretation is supported by the maximum age of molasse deposition in the Zhangjiatun member of the Xibiehe Formation. Overall, we suggest that Late Cambrian tholeiitic meta-diabase, Middle Ordovician pyroxene andesite, and Late Ordovician-Early Silurian tonalite formed above the northward-subducting and simultaneously seaward-retreating of Paleo-Asian Ocean plate. Subsequently, the northern arc collided with the North China Craton and post-orogenic extension occurred

  3. The tectonic evolution of the eastern Himalaya syntaxis since the collision of the Indian and Eurasian plates%印度与欧亚板块碰撞以来东喜马拉雅构造结的演化

    Institute of Scientific and Technical Information of China (English)

    丁林; 钟大赉

    2013-01-01

    Based on the field mapping, structures measuring and pre-studies reviewing in these areas, this paper identify and describe the major thrust faults, normal faults and strike-slip faults, anticlines ( antiforms ) and synclines ( synforms) , then discuss the relationship of their structural positions with the dentation of the Indian plate and rotation of the Indochina block, and how these structures accommodated for the Indian plate, which continued to push northward into the eastern Himalayan syntaxis. The eastern Himalayan syntaxis is composed of three syntaxises which gradually changed younger from north to south, such as the NE direction Namjag-Barwa anticline, the NW trending Siang syntaxis in the middle and the NE Asam syncline. These three tectonics result from the dentation of the NE Indian plate, the extension of the Himalayan arc and the rotation of the Indochina block. The Namjag-Barwa pop-up structure was formed in the center of the Namja-Barwa syntaxis with the dentation of the High Himalayan crystalline rock basement into the Gangdes Arc under the coordination of the Pai and Aniqiao strike-slip faults. In the NW side of Namjag-Barwa within Gangdese Arc, because of the tilting uplift and gravity sliding, the Gangdese cover was decoupled with the crystalline basement along Dongjiu detachment fault,and the hingwall of the fault slide to the NW direction. In the NE side of the Namjag-Barwa syntaxis within the Eurasian continent, due to the extrusion and rotation of the Indochina block, a series of NW trending strike-slip faults was formatted, such as Sagaing fault, Jiali-Gaoligpng fault,Lanchang river fault and Red river fault.%在野外填图,构造观察及前人研究的基础上,本文识别并描述了东喜马拉雅构造结中的推覆断裂、正断裂及走滑断裂、背斜(形)和向斜(形)等构造类型,讨论了这些构造位置及与印度板块挤入,印支地块旋转的关系,还探讨了东喜马拉雅构造结对印度板块持续向

  4. Mafic sill/dykes intruding into late Maastrichtian-early Paleocene calciclastic units, NE-Turkey: Petrographical and geochemical features of latest magmatic activity before collision in the eastern Sakarya zone

    Science.gov (United States)

    Aydin, Faruk; Oǧuz, Simge; Karsli, Orhan; Kandemir, Raif; Şen, Cüneyt; Uysal, İbrahim

    2017-04-01

    We present here new petrographical, mineralogical and whole-rock geochemical data for mafic sill/dykes intruding into late Maastrichtian-early Paleocene calciclastic units in the Düzköy (Trabzon) and Cankurtaran (Artvin) areas (NE Turkey) of the eastern Sakarya zone (ESZ) in order to decipher the latest magmatic activity in the final stage of subduction-related magmatism of the ESZ. U-Pb zircon dating for the mafic sill/dykes in the region yielded ages varying from 83.6 to 78.5Ma (i.e. Early Campanian). Mafic sill/dykes consist of mostly basalts and lesser basaltic-andesites with komatiitic basalts. Most of the dyke samples display aphyric to porphyritic texture with phenocrysts of plagioclase (mostly replaced by calcite), clinopyroxene (partly uralized), olivine (almost serpentinized), and amphibole (partly chloritized). Based on the MgO, Nb and Zr contents with Nb/Y ratio, the mafic dykes from Düzköy area are mainly classified as two subgroups (basalts and basaltic andesites) while those of Cankurtaran can be divided into three different groups (low- and high-Nb normal basalts and komatitic basalts). Düzköy basaltic dykes have higher MgO (3.8-7.8%) and lower Nb (3-4ppm) and Zr (53-62ppm) contents with Nb/Y ratio (˜0.2) than those of Düzköy basaltic-andesitic dykes (MgO: ˜1.8%, Nb: 6-15ppm, Zr: 106-145ppm, Nb/Y: 0.3-0.6). On the other hand, Cankurtaran mafic sill/dykes have relatively high MgO contents (˜4-20%). These sill/dykes with 15-20% of MgO and group 1 and 4.0-4.4% for group 2), Nb (3-14ppm for group 1 and 19-21ppm for group 2), Zr (94-111ppm for group 1 and 125-140ppm for group 2) contents, and Nb/Y ratio (˜0.2-0.8 for group 1 and (˜1.0-1.2 for group 2). Although the studied mafic sill/dykes have generally subalkaline composition, they show a geochemical character changing from mostly tholeiitic to rarely calc-alkaline and show typical features of late Cretaceous subduction-related magmatic rocks as in the ESZ. On the chondrite-normalized REE

  5. From collisions to clusters

    DEFF Research Database (Denmark)

    Loukonen, Ville; Bork, Nicolai; Vehkamaki, Hanna

    2014-01-01

    -principles molecular dynamics collision simulations of (sulphuric acid)1(water)0, 1 + (dimethylamine) → (sulphuric acid)1(dimethylamine)1(water)0, 1 cluster formation processes. The simulations indicate that the sticking factor in the collisions is unity: the interaction between the molecules is strong enough...... to overcome the possible initial non-optimal collision orientations. No post-collisional cluster break up is observed. The reasons for the efficient clustering are (i) the proton transfer reaction which takes place in each of the collision simulations and (ii) the subsequent competition over the proton...

  6. Collision Induced Galaxy Formation

    CERN Document Server

    Balland, C; Schäffer, R

    1997-01-01

    We present a semi-analytical model in which galaxy collisions and strong tidal interactions, both in the field and during the collapse phase of groups and clusters help determine galaxy morphology. From a semi-analytical analysis based on simulation results of tidal collisions (Aguilar & White 1985), we propose simple rules for energy exchanges during collisions that allow to discriminate between different Hubble types: efficient collisions result in the disruption of disks and substantial star formation, leading to the formation of elliptical galaxies; inefficient collisions allow a large gas reservoir to survive and form disks. Assuming that galaxy formation proceeds in a Omega_0=1 Cold Dark Matter universe, the model both reproduces a number of observations and makes predictions, among which are the redshifts of formation of the different Hubble types in the field. When the model is normalized to the present day abundance of X-ray clusters, the amount of energy exchange needed to produce elliptical gal...

  7. Bubble collision with gravitation

    CERN Document Server

    Hwang, Dong-il; Lee, Wonwoo; Yeom, Dong-han

    2012-01-01

    In this paper, we study vacuum bubble collisions with various potentials including gravitation, assuming spherical, planar, and hyperbolic symmetry. We use numerical calculations from double-null formalism. Spherical symmetry can mimic the formation of a black hole via multiple bubble collisions. Planar and especially hyperbolic symmetry describes two bubble collisions. We study both cases, when two true vacuum regions have the same field value or different field values, by varying tensions. For the latter case, we also test symmetric and asymmetric bubble collisions, and see details of causal structures. If the colliding energy is sufficient, then the vacuum can be destabilized, and it is also demonstrated. This double-null formalism can be a complementary approach in the context of bubble collisions.

  8. Collisions of Random Walks

    CERN Document Server

    Barlow, Martin T; Sousi, Perla

    2010-01-01

    A recurrent graph $G$ has the infinite collision property if two independent random walks on $G$, started at the same point, collide infinitely often a.s. We give a simple criterion in terms of Green functions for a graph to have this property, and use it to prove that a critical Galton-Watson tree with finite variance conditioned to survive, the incipient infinite cluster in $\\Z^d$ with $d \\ge 19$ and the uniform spanning tree in $\\Z^2$ all have the infinite collision property. For power-law combs and spherically symmetric trees, we determine precisely the phase boundary for the infinite collision property.

  9. Electron-molecule collisions

    CERN Document Server

    Takayanagi, Kazuo

    1984-01-01

    Scattering phenomena play an important role in modern physics. Many significant discoveries have been made through collision experiments. Amongst diverse kinds of collision systems, this book sheds light on the collision of an electron with a molecule. The electron-molecule collision provides a basic scattering problem. It is scattering by a nonspherical, multicentered composite particle with its centers having degrees of freedom of motion. The molecule can even disintegrate, Le., dissociate or ionize into fragments, some or all of which may also be molecules. Although it is a difficult problem, the recent theoretical, experimental, and computational progress has been so significant as to warrant publication of a book that specializes in this field. The progress owes partly to technical develop­ ments in measurements and computations. No less important has been the great and continuing stimulus from such fields of application as astrophysics, the physics of the earth's upper atmosphere, laser physics, radiat...

  10. Ion Collision, Theory

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, Anil K.

    2013-09-11

    The outcome of a collision between an ion and neutral species depends on the chemical and physical properties of the two reactants, their relative velocities, and the impact parameter of their trajectories. These include elastic and inelastic scattering of the colliding particles, charge transfer (including dissociative charge transfer), atom abstraction, complex formation and dissociation of the colliding ion. Each of these reactions may be characterized in terms of their energy-dependent rate coefficients, cross sections and reaction kinetics. A theoretical framework that emphasizes simple models and classical mechanics is presented for these processes. Collision processes are addressed in two categories of low-energy and high-energy collisions. Experiments under thermal or quasi-thermal conditions–swarms, drift tubes, chemical ionization and ion cyclotron resonance are strongly influenced by long-range forces and often involve collisions in which atom exchange and extensive energy exchange are common characteristics. High-energy collisions are typically impulsive, involve short-range intermolecular forces and are direct, fast processes.

  11. The Eastern Partnership

    DEFF Research Database (Denmark)

    Nielsen, Kristian L.; Vilson, Maili

    2014-01-01

    When the EU launched the Eastern Partnership (EaP) in 2009, it did so with much rhetoric about projecting its soft power into Eastern Europe. Yet today, the EU's soft power project seems to have stalled, with developments in the region being less than favourable. This article argues that the EaP ...

  12. Eastern Europe's Silicon Rush

    Science.gov (United States)

    Woodard, Colin

    2007-01-01

    This article presents how the fast expansion of information technology industry in eastern Slovakia is putting a strain on its labor supply. Suddenly, computer-science graduates have become one of the former Eastern Bloc's greatest assets, attracting multinational technology companies hungry for skilled programmers, technicians, and engineers.…

  13. Multiple collisions in turbulent flows

    CERN Document Server

    kuhle, Michel Voß; Wilkinson, Michael; Pumir, Alain

    2013-01-01

    In turbulent suspensions, collision rates determine how rapidly particles coalesce or react with each other. To determine the collision rate, many numerical studies rely on the 'Ghost Collision Approximation' (GCA), which simply records how often pairs of point particles come within a threshold distance. In many applications, the suspended particles stick (or in the case of liquid droplets, coalesce) upon collision, and it is the frequency of first contact which is of interest. If a pair of 'ghost' particles undergoes multiple collisions, the GCA may overestimate the true collision rate. Here, using fully resolved Direct Numerical Simulations of turbulent flows at moderate Reynolds number (R_\\lambda = 130), we investigate the prevalence and properties of multiple collisions. We demonstrate that the GCA leads to a systematic overestimate of the collision rate, which is of the order of 15% when the particle inertia is small, and slowly decreases when inertia increases. We investigate the probability P(N) for a ...

  14. Gyrokinetic linearized Landau collision operator

    DEFF Research Database (Denmark)

    Madsen, Jens

    2013-01-01

    The full gyrokinetic electrostatic linearized Landau collision operator is calculated including the equilibrium operator, which represents the effect of collisions between gyrokinetic Maxwellian particles. First, the equilibrium operator describes energy exchange between different plasma species...

  15. Vocal Fold Collision Modeling

    DEFF Research Database (Denmark)

    Granados, Alba; Brunskog, Jonas; Misztal, M. K.

    2015-01-01

    When vocal folds vibrate at normal speaking frequencies, collisions occurs. The numerics and formulations behind a position-based continuum model of contact is an active field of research in the contact mechanics community. In this paper, a frictionless three-dimensional finite element model...... of the vocal fold collision is proposed, which incorporates different procedures used in contact mechanics and mathematical optimization theories. The penalty approach and the Lagrange multiplier method are investigated. The contact force solution obtained by the penalty formulation is highly dependent...

  16. Ice particle collisions

    Science.gov (United States)

    Sampara, Naresh; Turnbull, Barbara; Hill, Richard; Swift, Michael

    2017-04-01

    Granular interactions of ice occur in a range of geophysical, astrophysical and industrial applications. For example, Saturn's Rings are composed of icy particles from micrometers to kilometres in size - inertial and yet too small to interact gravitationally. In clouds, ice crystals are smashed to pieces before they re-aggregate to for snow floccules in a process that is very much open to interpretation. In a granular flow of ice particles, the energy spent in collisions can lead to localized surface changes and wetting, which in turn can promote aggregation. To understand the induced wetting and its effects, we present two novel experimental methods which provide snippets of insight into the collisional behaviour of macroscopic ice particles. Experiment 1: Microgravity experiments provide minute details of the contact between the ice particles during the collision. A diamagnetic levitation technique, as alternative to the parabolic flight or falling tower experiments, was used to understand the collisional behaviour of individual macroscopic icy bodies. A refrigerated cylinder, that can control ambient conditions, was inserted into the bore of an 18 Tesla superconducting magnet and cooled to -10°C. Initial binary collisions were created, where one 4 mm ice particle was levitated in the magnet bore whilst another particle was dropped vertically from the top of the bore. The trajectories of both particles were captured by high speed video to provide the three-dimensional particle velocities and track the collision outcome. Introducing complexity, multiple particles were levitated in the bore and an azimuthal turbulent air flow introduced, allowing the particles to collide with other particles within a coherent fluid structure (mimicking Saturn's rings, or an eddy in a cloud). In these experiments, a sequence of collisions occur, each one different to the previous one due to the changes in surface characteristics created by the collisions themselves. Aggregation

  17. CMS SEES FIRST COLLISIONS

    CERN Multimedia

      A very special moment.  On 23rd November, 19:40 we recorded our first collisions with 450GeV beams well centred in CMS.   If you have any comments / suggestions please contact Karl Aaron GILL (Editor)

  18. Droplet collisions in turbulence

    NARCIS (Netherlands)

    Oldenziel, G.

    2014-01-01

    Liquid droplets occur in many natural phenomena and play an important role in a large number of industrial applications. One of the distinct properties of droplets as opposed to solid particles is their ability to merge, or coalesce upon collision. Coalescence of liquid drops is of importance in for

  19. Droplet collisions in turbulence

    NARCIS (Netherlands)

    Oldenziel, G.

    2014-01-01

    Liquid droplets occur in many natural phenomena and play an important role in a large number of industrial applications. One of the distinct properties of droplets as opposed to solid particles is their ability to merge, or coalesce upon collision. Coalescence of liquid drops is of importance in for

  20. Photon-photon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J.

    1988-07-01

    Highlights of the VIIIth International Workshop on Photon-Photon Collisions are reviewed. New experimental and theoretical results were reported in virtually every area of ..gamma gamma.. physics, particularly in exotic resonance production and tests of quantum chromodynamics where asymptotic freedom and factorization theorems provide predictions for both inclusive and exclusive ..gamma gamma.. reactions at high momentum transfer. 73 refs., 12 figs.

  1. Elementary Collisions with HADES

    CERN Document Server

    Fröhlich, I; Agakichiev, G; Agodi, C; Balanda, A; Bellia, G; Belver, D; Belyaev, A; Blanco, A; Böhmer, M; Boyard, J L; Braun-Munzinger, P; Cabanelas, P; Castro, E; Chernenko, S; Christ, T; Destefanis, M; Daz, J; Dohrmann, F; Dybczak, A; Eberl, T; Fabbietti, L; Fateev, O; Finocchiaro, P; Fonte, Paulo J R; Friese, J; Galatyuk, T; Garzn, J A; Gernhuser, R; Gilardi, C; Golubeva, M; Gonzalez-Diaz, D; Grosse, E; Guber, F; Heilmann, M; Hennino, T; Holzmann, R; Ierusalimov, A; Iori, I; Ivashkin, A; Jurkovic, M; Kmpfer, B; Kanaki, K; Karavicheva, T; Kirschner, D; König, I; König, W; Kolb, B W; Kotte, R; Kozuch, A; Krizek, F; Krcken, R; Khn, W; Kugler, A; Kurepin, A; Lamas-Valverde, J; Lang, S; Lange, J S; Lopes, L; Maier, L; Mangiarotti, A; Marn, J; Markert, J; Metag, V; Michalska, B; Mishra, D; Morinire, E; Mousa, J; Müntz, C; Naumann, Lutz; Novotny, R; Otwinowski, J; Pachmayer, Y C; Palka, M; Parpottas, Y; Pechenov, V; Pechenova, O; Prez Cavalcanti, T; Przygoda, W; Ramstein, B; Reshetin, A; Roy-Stephan, M; Rustamov, A; Sadovskii, A; Sailer, B; Salabura, P; Schmah, A; Simon, R; Spataro, S; Spruck, B; Strbele, H; Stroth, J; Sturm, C; Sudol, M; Tarantola, A; Teilab, K; Tlustý, P; Traxler, M; Trebacz, R; Tsertos, H; Veretenkin, I; Wagner, V; Wen, H; Wisniowski, M; Wojcik, T; Wstenfeld, J; Yurevich, S; Zanevsky, Y; Zumbruch, P

    2007-01-01

    The "High Acceptance DiElectron Spectrometer" (HADES) at GSI, Darmstadt, is investigating the production of e+e- pairs in A+A, p+A and N+N collisions. The latter program allows for the reconstruction of individual sources. This strategy will be roughly outlined in this contribution and preliminary pp/pn data is shown.

  2. Collision Probability Analysis

    DEFF Research Database (Denmark)

    Hansen, Peter Friis; Pedersen, Preben Terndrup

    1998-01-01

    probability, i.e. a study of the navigator's role in resolving critical situations, a causation factor is derived as a second step.The report documents the first step in a probabilistic collision damage analysis. Future work will inlcude calculation of energy released for crushing of structures giving...

  3. Collisions in soccer kicking

    DEFF Research Database (Denmark)

    Andersen, Thomas Bull; Dörge, Henrik C.; Thomsen, Franz Ib

    1999-01-01

    An equation to describe the velocity of the soccer ball after the collision with a foot was derived. On the basis of experimental results it was possible to exclude certain factors and only describe the angular momentum of the system, consisting of the shank, the foot and the ball, leading...

  4. Challenge for Mesozoic hydrocarbon exploration in the Eastern Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, S.; Rukmiati, M.G.; Sitompul, N. [Pertamina Exploration and Production, Jakarta (Indonesia)

    1996-12-31

    The eastern part of Indonesia covers approximately 3 million square kilometers, 35 percent being landmass and 65 percent covered by ocean. Only three of 38 sedimentary basins are producing hydrocarbon (Salawati, Bintuni, and Seram Basins). Oil and gas have discovered in the Lariang, Bone, Timor, Banggai, Sula and Biak Basins, however the discoveries have not developed yet. Hydrocarbon systems in Northern Australia and Papua New Guinea give the major contributions to the geological idea of Pre-Tertiary section in the less explored area in the Eastern Indonesia. The Triassic-Middle Jurassic marine carbonaceous shale sequences are the main hydrocarbon source rock in the Irian Jaya and surrounding area (Buton, gula and Seram basins). The main Mesozoic reservoir are the Kembelangan Formation in the Bintuni Basin of Irian Jaya and Bobong Formation in the North Sula Region. Exploration play types in the Eastern Indonesia can be divided into five types: 1 - Peri Cratonic, 2 - Marginal Rift Graben, 3 - Thrust Fold Belt Island Arc, 4 - Early Collision and 5 -Microcontinental Block - Advanced Collision. Recent discoveries through Mesozoic section in Eastern Indonesia are: Roabiba-1 (1990) in Bintuni Basin-Irian Jaya (Kambelangan Formation); Loku- 1 (1990) in North Sula region (Pre-Tertiary sediments); Oseil-1 (1993/94) in Bula-Seram Basin (Jurassic Manusela Formation); Elang-1 (1 994); Kakaktua-1 (1994) and Laminaria-1 in North Bonaparte Basin (Upper Jurassic Sands).

  5. Eastern Equine Encephalitis

    Science.gov (United States)

    ... bite of an infected mosquito. Eastern equine encephalitis (EEE) is a rare illness in humans, and only ... EEEV have no apparent illness. Severe cases of EEE (involving encephalitis, an inflammation of the brain) begin ...

  6. Collision Probability Analysis

    DEFF Research Database (Denmark)

    Hansen, Peter Friis; Pedersen, Preben Terndrup

    1998-01-01

    It is the purpose of this report to apply a rational model for prediction of ship-ship collision probabilities as function of the ship and the crew characteristics and the navigational environment for MS Dextra sailing on a route between Cadiz and the Canary Islands.The most important ship and crew...... characteristics are: ship speed, ship manoeuvrability, the layout of the navigational bridge, the radar system, the number and the training of navigators, the presence of a look out etc. The main parameters affecting the navigational environment are ship traffic density, probability distributions of wind speeds...... probability, i.e. a study of the navigator's role in resolving critical situations, a causation factor is derived as a second step.The report documents the first step in a probabilistic collision damage analysis. Future work will inlcude calculation of energy released for crushing of structures giving...

  7. Crustal Flows beneath the Eastern Tibetan Plateau Revealed by Magnetotelluric Observations

    Institute of Scientific and Technical Information of China (English)

    BAI Denghai; TENG Jiwen; MA Xiaobing; KONG Xiangru

    2011-01-01

    @@ The ongoing collision of the Indian and Asian continents has created the Himalayan and Tibetan plateau through a range of deformation processes that include crustal thickening, delamination, lateral extrusion and crustal flow.A debate continues as to which of these processes are most significant in terms of the overall mass balance of this continent-continent collision.In eastern Tibet GPS data show large-scale motion of the surface has been occurring around the eastern Himalayan syntaxis (EHS), but the nature of deformation at depth remains unresolved.A large-scale crustal flow has been proposed as an explanation for regional uplift in eastern Tibet, but existing geophysical data do not constrain the pattern of flow.

  8. Topics in atomic collision theory

    CERN Document Server

    Geltman, Sydney; Brueckner, Keith A

    1969-01-01

    Topics in Atomic Collision Theory originated in a course of graduate lectures given at the University of Colorado and at University College in London. It is recommended for students in physics and related fields who are interested in the application of quantum scattering theory to low-energy atomic collision phenomena. No attention is given to the electromagnetic, nuclear, or elementary particle domains. The book is organized into three parts: static field scattering, electron-atom collisions, and atom-atom collisions. These are in the order of increasing physical complexity and hence necessar

  9. Road rage and collision involvement.

    Science.gov (United States)

    Mann, Robert E; Zhao, Jinhui; Stoduto, Gina; Adlaf, Edward M; Smart, Reginald G; Donovan, John E

    2007-01-01

    To assess the contribution of road rage victimization and perpetration to collision involvement. The relationship between self-reported collision involvement and road rage victimization and perpetration was examined, based on telephone interviews with a representative sample of 4897 Ontario adult drivers interviewed between 2002 and 2004. Perpetrators and victims of both any road rage and serious road rage had a significantly higher risk of collision involvement than did those without road rage experience. This study provides epidemiological evidence that both victims and perpetrators of road rage experience increased collision risk. More detailed studies of the contribution of road rage to traffic crashes are needed.

  10. Eastern Pacific Ocean Conference

    Science.gov (United States)

    The promotion of interaction among investigators of all oceanographic disciplines studying the eastern Pacific Ocean was the goal of the 1990 Eastern Pacific Ocean Conference (EPOC), held October 17-19 on the snow-covered slopes of Mt. Hood, Oreg. Thirty oceanographers representing all disciplines attended.Dick Barber, Duke University Marine Lab, Beaufort, N.C., chaired a session on the eastern equatorial Pacific Ocean, emphasizing issues related to biological activity. Steve Ramp of the Naval Postgraduate School in Montery, Calif., chaired a session on recent results from northern and central California experiments. On October 19, following an early morning earthquake, a business meeting and discussions regarding a collaboration in future experiments were held.

  11. Molecular collision theory

    CERN Document Server

    Child, M S

    2010-01-01

    This high-level monograph offers an excellent introduction to the theory required for interpretation of an increasingly sophisticated range of molecular scattering experiments. There are five helpful appendixes dealing with continuum wavefunctions, Green's functions, semi-classical connection formulae, curve-crossing in the momentum representation, and elements of classical mechanics.The contents of this volume have been chosen to emphasize the quantum mechanical and semi-classical nature of collision events, with little attention given to purely classical behavior. The treatment is essentiall

  12. Collision of two Hopfions

    CERN Document Server

    Arrayás, M

    2016-01-01

    We study the collision of two hopfions or Hopf-Ra\\~nada electromagnetic fields. The superposition of two of such fields, travelling in opposite directions, yields different topology for the electric and magnetic field lines. Controlling the angular momentum of such fields, we can control the topology of the flow associated to the field lines, and the energy distribution. The concept of electromagnetic helicity and the exchange between its magnetic and electric components are used to explain the different behaviours observed when the angular momentum is reversed.

  13. Atomic collisions involving pulsed positrons

    DEFF Research Database (Denmark)

    Merrison, J. P.; Bluhme, H.; Field, D.

    2000-01-01

    Conventional slow positron beams have been widely and profitably used to study atomic collisions and have been instrumental in understanding the dynamics of ionization. The next generation of positron atomic collision studies are possible with the use of charged particle traps. Not only can large...... of accelerators for producing intense positron pulses will be discussed in the context of atomic physics experiments....

  14. Outer Dynamics of Ship Collisions

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup

    1996-01-01

    The purpose is to present analysis procedures for the motion of ships during ship-ship collisions and for ship collisions with offshore structures. The aim is to estimate that part of the lost kinetic energy which will have to be absorbed by rupture and plastic damage of the colliding structures....

  15. Photon-photon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J.

    1985-01-01

    The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of ..cap alpha../sub s/ and ..lambda../sup ms/ from the ..gamma..*..gamma.. ..-->.. ..pi../sup 0/ form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from ..gamma gamma.. ..-->.. H anti H, reconstruction of sigma/sub ..gamma gamma../ from exclusive channels at low W/sub ..gamma gamma../, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z/sup 0/ and W/sup + -/ beams from e ..-->.. eZ/sup 0/ and e ..-->.. nu W will become important. 44 references.

  16. DISCOVERING BEIJING Eastern Promise

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Dongcheng District, literally meaning eastern city, covers Beijing’s downtown area to the northeast of the central axis of old Beijing. The district has a total area of 25 square km and a population of 600,000. With a large number of cultural and historical sites and tourist attractions,

  17. Eastern Spruce Dwarf Mistletoe

    Science.gov (United States)

    F. Baker; Joseph O' Brien; R. Mathiasen; Mike Ostry

    2006-01-01

    Eastern spruce dwarf mistletoe (Arceuthobium pusillum) is a parasitic flowering plant that causes the most serious disease of black spruce (Picea mariana) throughout its range. The parasite occurs in the Canadian provinces of Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland; in the Lake States of Minnesota,...

  18. Eastern Frequency Response Study

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N.W.; Shao, M.; Pajic, S.; D' Aquila, R.

    2013-05-01

    This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

  19. Collisions in young triple systems

    CERN Document Server

    Rawiraswattana, Krisada; Goodwin, Simon P

    2011-01-01

    We perform N-body simulations of young triple systems consisting of two low-mass companions orbiting around a significantly more massive primary. We find that, when the orbits of the companions are coplanar and not too widely separated, the chance of a collision between the two companions can be as high as 20 per cent. Collisions between one of the companions (always the less massive) and the primary can also occur in systems with unequal-mass companions. The chance of collisions is a few per cent in systems with more realistic initial conditions, such as with slightly non-coplanar orbits and unequal-mass companions. If the companions start widely separated then collision are very rare except in some cases when the total mass of the companions is large. We suggest that collisions between members of young multiple systems may explain some unusual young multiple systems such as apparently non-coeval companions.

  20. ALPASS: Teleseismic Tomography of the Eastern Alps

    Science.gov (United States)

    Brueckl, E.; Mitterbauer, U.; Lippitsch, R.; Behm, M.; ALPASS Working Group

    2007-12-01

    The Eastern Alps were formed by the north-south directed collision of the Adriatic (African) and European plates and a subsequent tectonic escape of crustal fragments to the unconstrained margin in the east, represented by the Pannonian Basin. Recent controlled source seismic experiments (TRANSALP, CELEBRATION 2000, and ALP 2002) revealed significant internal structures of the crust and the Moho topography. However, deeper plate tectonic structures (e.g. subducting slab) are still under debate. ALPASS is a passive seismic monitoring project aiming to reveal lower lithosphere and upper mantle beneath the wider Eastern Alpine region, and to contribute to a better understanding of the geodynamic processes at work. By cooperation of Austria, Croatia, Finland, Hungary, Poland, and USA 57 temporary seismic recording stations were deployed from May 2005 until May 2006. The layout was designed to extend the efforts of earlier experiments (e.g. TRANSALP) and to support two other passive seismic experiments (BOHEMA, Carpathian Basin Project), which are overlapping in the investigation area. Additionally, data from permanent networks was collected to improve coverage of the investigation area. 144 events (50% with M > 5.6) from epicentre distances between 30° and 100° were selected for teleseismic inversion. Travel time picking of P-wave arrivals has been done by a semi-automatic correlation technique. Crustal corrections benefit from the high resolution velocity model of the crust and the new Moho map derived from CELEBRATION 2000 and ALP 2002 data. First results of teleseismic inversion will be presented and discussed with respect to crustal structures revealed by the controlled source experiments, tomographic models generated during earlier studies, and their consequences for the conception of plate tectonics in the Eastern Alps.

  1. Sixteenth International Conference on the physics of electronic and atomic collisions

    Energy Technology Data Exchange (ETDEWEB)

    Dalgarno, A.; Freund, R.S.; Lubell, M.S.; Lucatorto, T.B. (eds.)

    1989-01-01

    This report contains abstracts of papers on the following topics: photons, electron-atom collisions; electron-molecule collisions; electron-ion collisions; collisions involving exotic species; ion- atom collisions, ion-molecule or atom-molecule collisions; atom-atom collisions; ion-ion collisions; collisions involving rydberg atoms; field assisted collisions; collisions involving clusters and collisions involving condensed matter.

  2. Reversible Simulations of Elastic Collisions

    CERN Document Server

    Perumalla, Kalyan S

    2013-01-01

    Consider a system of N identical hard spherical particles moving in a d-dimensional box and undergoing elastic, possibly multi-particle, collisions. We develop a new algorithm that recovers the pre-collision state from the post-collision state of the system, across a series of consecutive collisions, with essentially no memory overhead. The challenge in achieving reversibility for an n-particle collision (where, n << N) arises from the presence of nd-d-1 degrees of freedom during each collision, and from the complex geometrical constraints placed on the colliding particles. To reverse the collisions in a traditional simulation setting, all of the particular realizations of these degrees of freedom during the forward simulation must be saved. This limitation is addressed here by first performing a pseudo-randomization of angles, ensuring determinism in the reverse path for any values of n and d. To address the more difficult problem of geometrical and dynamic constraints, a new approach is developed whic...

  3. Collision Risk Analysis for HSC

    DEFF Research Database (Denmark)

    Urban, Jesper; Pedersen, Preben Terndrup; Simonsen, Bo Cerup

    1999-01-01

    for a HSC on a given route, an analysis of the released energy during a collision, analytical closed form solutions for the absorbed energy in the structure and finally an assessment of the overall structural crushing behaviour of the vessel, including the level of acceleration and the size of the crushing...... analysis tools to quantify the effect of the high speed have been available. Instead nearly all research on ship accidents has been devoted to analysis of the consequences of given accident scenarios. The proposed collision analysis includes an analysis which determines the probability of a collision...

  4. On Impact Mechanics in Ship Collisions

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Zhang, Shengming

    1998-01-01

    The purpose of this paper is to present analytical, closed-form expressions for the energy released for crushing and the impact impulse during ship collisions. Ship-ship collisions, ship collisions with rigid walls and ship collisions with flexible offshore structures are considered. The derived ...

  5. Seismic anisotropy of upper mantle in eastern China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Based on the polarization analysis of teleseismic SKS waveform data recorded at 65 seismic stations which respectively involved in the permanent and temporary broadband seismograph networks deployed in eastern China, the SKS fast-wave direction and the delay time between the fast and slow shear waves at each station were determined by use of SC method and the stacking analysis method, and then the image of upper mantle anisotropy in eastern China was acquired. In the study region, from south to north, the fast-wave polarization directions are basically EW in South China, gradually clockwise rotate to NWW-SEE in North China, then to NW-SE in Northeast China. The delay time falls into the interval [0.41 s, 1.52 s]. Anisotropic characteristics in eastern China indicate that the upper mantle anisotropy is possibly caused by both the collision between the Indian and Eurasian Plates and the subduction from the Pacific and Philippine Sea Plates to the Eurasian Plate. The collision between two plates made the crust of western China thickening and uplifting and the material eastwards extruding, and then caused the upper mantle flow eastwards and southeastwards. The subduction of Pacific Plate and Philippine Sea Plate has resulted in the lithosphere and the asthenosphere deformation in eastern China, and made the alignment of upper mantle peridotite lattice parallel to the deformation direction. The fast-wave polarization direction is consistent with the direction of lithosphere extension and the GPS velocity direction, implying that the crust-upper mantle deformation is possibly a vertically coherent deformation.

  6. Seismic anisotropy of upper mantle in eastern China

    Institute of Scientific and Technical Information of China (English)

    CHANG LiJun; WANG ChunYong; Ding ZhiFeng

    2009-01-01

    Based on the polarization analysis of teleseismic SKS waveform data recorded at 65 seismic stations which respectively involved in the permanent and temporary broadband seismograph networks de-ployed in eastern China,the SKS fast-wave direction and the delay time between the fast and slow shear waves at each station were determined by use of SC method and the stacking analysis method,and then the image of upper mantle anisotropy in eastern China was acquired.In the study region,from south to north,the fast-wave polarization directions are basically EW in South China,gradually clock-wise rotate to NWW-SEE in North China,then to NW-SE in Northeast China.The delay time falls into the Interval [0.41 s,1.52 s].Anisotropic characteristics in eastern China indicate that the upper mantle anisotropy is possibly caused by both the collision between the Indian and Eurasian Plates and the subduction from the Pacific and Philippine Sea Plates to the Eurasian Plate.The collision between two plates made the crust of western China thickening and uplifting and the material eastwards extruding,and then caused the upper mantle flow eastwards and southeastwards.The subduction of Pacific Plate and Philippine Sea Plate has resulted in the lithosphere and the asthenosphere deformation in eastern China,and made the alignment of upper mantle peridotite lattice parallel to the deformation direction.The fast-wave polarization direction is consistent with the direction of lithosphere extension and the GPS velocity direction,implying that the crust-upper mantle deformation is possibly a vertically co-herent deformation.

  7. Collision Geometry and Flow in Uranium+Uranium Collisions

    CERN Document Server

    Goldschmidt, Andy; Shen, Chun; Heinz, Ulrich

    2015-01-01

    Using event-by-event viscous fluid dynamics to evolve fluctuating initial density profiles from the Monte-Carlo Glauber model for U+U collisions, we report a "knee"-like structure in the elliptic flow as a function of collision centrality, located around the 0.5% most central collisions as measured by the final charged multiplicity. This knee is due to the preferential selection of tip-on-tip collision geometries by a high-multiplicity trigger. Such a knee structure is not seen in the STAR data. This rules out the two-component MC-Glauber model for initial energy and entropy production. Hence an enrichment of tip-tip configurations by triggering solely on high-multiplicity in the U+U collisions does not work. On the other hand, by using the Zero Degree Calorimeters (ZDCs) coupled with event-shape engineering such a selection is possible. We identify the selection purity of body-body and tip-tip events in full-overlap U+U collisions. By additionally constraining the asymmetry of the ZDC signals we can further ...

  8. On impact mechanics in ship collisions

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Zhang, Shengming

    1998-01-01

    The purpose of this paper is to present analytical, closed-form expressions for the energy released for crushing and the impact impulse during ship collisions. Ship–ship collisions, ship collisions with rigid walls and ship collisions with flexible offshore structures are considered. The derived ...... of illustrative examples are presented. The procedure presented in the paper is well suited for inclusion in a probabilistic calculation model for damage of ship structures due to collisions....

  9. Radiative collision-induced photoionization

    Energy Technology Data Exchange (ETDEWEB)

    Nayfeh, M.H.; Payne, M.G.

    1978-05-01

    Semiclassical expressions of two-photon ionization of atoms induced by radiative collisions are derived. The dependence of the ionization yield on the atomic forces, field intensity, and energy gap is derived. Although absorption tends to decrease as the field intensity rises due to stimulated emission at the second crossing, the two-photon ionization yield can be nearly saturated at the first crossing, thus enhancing the absorption. Both regions, ionization in single collisions and ionization between collisions, are treated. In the latter we find that saturation of the ionization can be achieved at much reduced intensities. This process promises an extremely sensitive method for studying radiative collisions, especially when absorption or fluorescence becomes extremely weak.

  10. DROPLET COLLISION AND COALESCENCE MODEL

    Institute of Scientific and Technical Information of China (English)

    LI Qiang; CAI Ti-min; HE Guo-qiang; HU Chun-bo

    2006-01-01

    A new droplet collision and coalescence model was presented, a quick-sort method for locating collision partners was also devised and based on theoretical and experimental results, further advancement was made to the droplet collision outcome.The advantages of the two implementations of smoothed particle hydrodynamics (SPH)method were used to limit the collision of droplets to a given number of nearest droplets and define the probability of coalescence, numerical simulations were carried out for model validation. Results show that the model presented is mesh-independent and less time consuming, it can not only maintains the system momentum conservation perfectly, but not susceptible to initial droplet size distribution as well.

  11. Neuromorphic UAS Collision Avoidance Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Using biologically-inspired neuromorphic optic flow algorithms is a novel approach in collision avoidance for UAS. Traditional computer vision algorithms rely on...

  12. Robot Avoids Collisions With Obstacles

    Science.gov (United States)

    Cheung, Edward; Rosinski, Doug; Wegerif, Dan

    1993-01-01

    Developmental robot equipped with infrared sensors and control system acting in concert to enable manipulator arm to move around obstacles. Robot avoids collisions with other objects, even when moving in unpredictable ways. Control system requires no prior knowledge of environment.

  13. Collisions of Vortex Filament Pairs

    Science.gov (United States)

    Banica, Valeria; Faou, Erwan; Miot, Evelyne

    2014-12-01

    We consider the problem of collisions of vortex filaments for a model introduced by Klein et al. (J Fluid Mech 288:201-248, 1995) and Zakharov (Sov Phys Usp 31(7):672-674, 1988, Lect. Notes Phys 536:369-385, 1999) to describe the interaction of almost parallel vortex filaments in three-dimensional fluids. Since the results of Crow (AIAA J 8:2172-2179, 1970) examples of collisions are searched as perturbations of antiparallel translating pairs of filaments, with initial perturbations related to the unstable mode of the linearized problem; most results are numerical calculations. In this article, we first consider a related model for the evolution of pairs of filaments, and we display another type of initial perturbation leading to collision in finite time. Moreover, we give numerical evidence that it also leads to collision through the initial model. We finally study the self-similar solutions of the model.

  14. collision zone of an ISR

    CERN Multimedia

    This is a collision region from the world’s first proton collider, the Intersecting Storage Rings. The ISR was used at CERN from 1971-84 to study proton-proton collisions at the highest energy then available (60GeV). When operational, ISR collision regions were surrounded by detectors as shown in the photo. In 1972, the surprising discovery of fragments flying out sideways from head-on proton-proton collisions was the first evidence of quark-quark scattering inside the colliding protons . This was similar to Rutherford’s observation in 1911 of alpha particles scattering off the tiny nucleus inside atoms of gold. The ISR beamtubes had to be as empty as outer space, a vacuum 100 000 times better than other CERN machines at the time.

  15. collision region of the ISR

    CERN Multimedia

    1970-01-01

    This is a collision region from the world’s first proton collider, the Intersecting Storage Rings. The ISR was used at CERN from 1971-84 to study proton-proton collisions at the highest energy then available (60GeV). When operational, ISR collision regions were surrounded by detectors as shown in the photo. In 1972, the surprising discovery of fragments flying out sideways from head-on proton-proton collisions was the first evidence of quark-quark scattering inside the colliding protons . This was similar to Rutherford’s observation in 1911 of alpha particles scattering off the tiny nucleus inside atoms of gold. The ISR beamtubes had to be as empty as outer space, a vacuum 100 000 times better than other CERN machines at the time.

  16. Magmatism and Geodynamics of Eastern Turkey

    Science.gov (United States)

    Keskin, Mehmet; Oyan, Vural; Sharkov, Evgenii V.; Chugaev, Andrey V.; Genç, Ş. Can; Ünal, Esin; Aysal, Namık; Duru, Olgun; Kavak, Orhan

    2013-04-01

    Eastern Turkey has been an active collision zone for the last 15 My between the Arabian Plate and Eurasian continent. The collision initiated after the closure of the southern branch of the Neotethys Ocean by northward subduction beneath E Anatolia at ~15 Ma. The collision-related volcanism started immediately after the closure of the ocean (again at around 15 Ma) in the north of the present day Lake Van with the eruption of mostly intermediate to acid lavas displaying distinct subduction characteristics. Both continental collision and the magmatism are still active, because the Arabian plate still converges to Anatolia with a velocity of ~2.5 cm/y. The overriding Anatolian block experienced a major uplift event around 10 Ma. The region once resided below the sea level merged as a widespread plateau ~2 km above the sea level as part of a regional dome structure with ~1000 km diameter, extending from Central Anatolia in the West to Azerbaijan in the East. The first alkaline lavas derived from a relatively more enriched source erupted to the surface in the N of Lake Van coeval with the initiation of the uplift at around 10 Ma. The underthrusting Arabian platform, on the other hand, was deformed as a result of both crustal-scale east-west folds adjacent to the major thrust zone and extensional deformations perpendicular to the suture zone. Alkaline within-plate lavas with no subduction component erupted through these extension zones. This intraplate volcanism focused on the Karacadaǧ volcanic complex that covers an area of ~10,000 km2. Early Stage volcanism of Karacadaǧ was dominated by magmas derived from a shallower metasomatized (litospheric) mantle source, while magmas of the later stages were derived from deeper (asthenospheric) sources. The Karacadaǧ volcanic area of SE Anatolia was sourced by a garnet bearing, deep asthenospheric mantle which is similar to that of Afar in terms of its Pb isotopic ratios. This brings into question whether the mantle material

  17. Airborne Collision Avoidance System X

    Science.gov (United States)

    2015-06-01

    avoidance system on behalf of the Federal Aviation Adminis- tration (FAA). The current Traffic Alert and Collision Avoidance System II (TCAS II...transformations to the National Airspace System are being imple- mented through the FAA’s Next-Genera- tion Air Transportation System (NextGen). With the goal...weighted states to provide a single, optimal action. If a collision avoidance This work is sponsored by the Federal Aviation Administration under Air

  18. Do speed cameras reduce collisions?

    Science.gov (United States)

    Skubic, Jeffrey; Johnson, Steven B; Salvino, Chris; Vanhoy, Steven; Hu, Chengcheng

    2013-01-01

    We investigated the effects of speed cameras along a 26 mile segment in metropolitan Phoenix, Arizona. Motor vehicle collisions were retrospectively identified according to three time periods - before cameras were placed, while cameras were in place and after cameras were removed. A 14 mile segment in the same area without cameras was used for control purposes. Five cofounding variables were eliminated. In this study, the placement or removal of interstate highway speed cameras did not independently affect the incidence of motor vehicle collisions.

  19. Collision Geometry and Flow in Uranium+Uranium Collisions

    CERN Document Server

    Goldschmidt, Andy; Shen, Chun; Heinz, Ulrich

    2015-01-01

    Using event-by-event viscous fluid dynamics to evolve fluctuating initial density profiles from the Monte-Carlo Glauber model for U+U collisions, we report a "knee"-like structure in the elliptic flow as a function of collision centrality, located near 0.5% centrality as measured by the final charged multiplicity. This knee is due to the preferential selection of tip-on-tip collision geometries by a high-multiplicity trigger. Such a knee structure is not seen in the STAR data. This rules out the two-component MC-Glauber model for initial energy and entropy production. An enrichment of tip-tip configurations by triggering solely on high-multiplicity in the U+U collisions thus does not work. On the other hand, using the Zero Degree Calorimeters (ZDCs) coupled with event-shape engineering, we identify the selection purity of body-body and tip-tip events in the full-overlap U+U collisions. With additional constraints on the asymmetry of the ZDC signals one can further increases the probability of selecting tip-ti...

  20. A Habitat-based Wind-Wildlife Collision Model with Application to the Upper Great Plains Region

    Energy Technology Data Exchange (ETDEWEB)

    Forcey, Greg, M.

    2012-08-28

    Most previous studies on collision impacts at wind facilities have taken place at the site-specific level and have only examined small-scale influences on mortality. In this study, we examine landscape-level influences using a hierarchical spatial model combined with existing datasets and life history knowledge for: Horned Lark, Red-eyed Vireo, Mallard, American Avocet, Golden Eagle, Whooping Crane, red bat, silver-haired bat, and hoary bat. These species were modeled in the central United States within Bird Conservation Regions 11, 17, 18, and 19. For the bird species, we modeled bird abundance from existing datasets as a function of habitat variables known to be preferred by each species to develop a relative abundance prediction for each species. For bats, there are no existing abundance datasets so we identified preferred habitat in the landscape for each species and assumed that greater amounts of preferred habitat would equate to greater abundance of bats. The abundance predictions for bird and bats were modeled with additional exposure factors known to influence collisions such as visibility, wind, temperature, precipitation, topography, and behavior to form a final mapped output of predicted collision risk within the study region. We reviewed published mortality studies from wind farms in our study region and collected data on reported mortality of our focal species to compare to our modeled predictions. We performed a sensitivity analysis evaluating model performance of 6 different scenarios where habitat and exposure factors were weighted differently. We compared the model performance in each scenario by evaluating observed data vs. our model predictions using spearmans rank correlations. Horned Lark collision risk was predicted to be highest in the northwestern and west-central portions of the study region with lower risk predicted elsewhere. Red-eyed Vireo collision risk was predicted to be the highest in the eastern portions of the study region and in

  1. A Habitat-based Wind-Wildlife Collision Model with Application to the Upper Great Plains Region

    Energy Technology Data Exchange (ETDEWEB)

    Forcey, Greg, M.

    2012-08-28

    Most previous studies on collision impacts at wind facilities have taken place at the site-specific level and have only examined small-scale influences on mortality. In this study, we examine landscape-level influences using a hierarchical spatial model combined with existing datasets and life history knowledge for: Horned Lark, Red-eyed Vireo, Mallard, American Avocet, Golden Eagle, Whooping Crane, red bat, silver-haired bat, and hoary bat. These species were modeled in the central United States within Bird Conservation Regions 11, 17, 18, and 19. For the bird species, we modeled bird abundance from existing datasets as a function of habitat variables known to be preferred by each species to develop a relative abundance prediction for each species. For bats, there are no existing abundance datasets so we identified preferred habitat in the landscape for each species and assumed that greater amounts of preferred habitat would equate to greater abundance of bats. The abundance predictions for bird and bats were modeled with additional exposure factors known to influence collisions such as visibility, wind, temperature, precipitation, topography, and behavior to form a final mapped output of predicted collision risk within the study region. We reviewed published mortality studies from wind farms in our study region and collected data on reported mortality of our focal species to compare to our modeled predictions. We performed a sensitivity analysis evaluating model performance of 6 different scenarios where habitat and exposure factors were weighted differently. We compared the model performance in each scenario by evaluating observed data vs. our model predictions using spearmans rank correlations. Horned Lark collision risk was predicted to be highest in the northwestern and west-central portions of the study region with lower risk predicted elsewhere. Red-eyed Vireo collision risk was predicted to be the highest in the eastern portions of the study region and in

  2. India-Eurasia collision triggers formation of an oceanic microplate

    Science.gov (United States)

    Matthews, Kara; Müller, Dietmar; Sandwell, David

    2016-04-01

    Detailed mapping of seafloor tectonic fabric in the Indian Ocean, using high-resolution satellite-derived vertical gravity gradient data, reveals an extinct Pacific-style oceanic microplate - the Mammerickx Microplate - west of the Ninetyeast Ridge. It is one of the first Pacific-style microplates to be mapped outside the Pacific basin, suggesting that geophysical conditions during formation probably resembled those that have dominated at eastern Pacific ridges. The microplate formed at the Indian-Antarctic ridge and is bordered by an extinct ridge in the north and pseudofault in the south, whose conjugate is located north of the Kerguelen Plateau. Independent microplate rotation is indicated by asymmetric pseudofaults and rotated abyssal hill fabric, also identified in multibeam data. Magnetic anomaly picks and age estimates calculated from published spreading rates suggest formation during chron 21o (~47.3 Ma). Plate reorganizations can trigger ridge propagation and microplate development, and we propose that formation of the Mammerickx Microplate is linked with the initial 'soft' stage of the India-Eurasia collision. The collision altered the stress regime at the Indian-Antarctic ridge, leading to a change in segmentation and ridge propagation from an establishing transform fault. Fast Indian-Antarctic spreading that preceded microplate formation, and Kerguelen Plume activity may have facilitated ridge propagation via the production of thin and weak lithosphere. However, both factors had been present for tens of millions of years and are therefore unlikely to have triggered the event. Prior to the collision, this combination of fast spreading and plume activity was responsible for the production of a wide region of undulate seafloor to the north of the extinct ridge and 'W' shaped lineations that record back and forth ridge propagation. Microplate formation provides a means of dating the onset of the India-Eurasia collision, and is completely independent of and

  3. Supersonic Cloud Collision-II

    CERN Document Server

    Anathpindika, S

    2009-01-01

    In this, second paper of the sequel of two papers, we present five SPH simulations of fast head-on cloud collisions and study the evolution of the ram pressure confined gas slab. Anathpindika (2008) (hereafter paper I) considered highly supersonic cloud collisions and examined the effect of bending and shearing instabilities on the shocked gas slab. The post-collision shock here, as in paper I, is also modelled by a simple barotropic equation of state (EOS). However, a much stiffer EOS is used to model the shock resulting from a low velocity cloud collision. We explore the parameter space by varying the pre-collision velocity and the impact parameter. We observe that pressure confined gas slabs become Jeans unstable if the sound crossing time, $t_{cr}$, is much larger than the freefall time, $t_{ff}$, of putative clumps condensing out of them. Self gravitating clumps may spawn multiple/larger $N$-body star clusters. We also suggest that warmer gas slabs are unlikely to fragment and may end up as diffuse gas c...

  4. Brooks Range and eastern Alps: a tectonic comparison

    Energy Technology Data Exchange (ETDEWEB)

    Helwig, J.A.

    1985-04-01

    A comparison of the tectonic evolution of the Brooks Range (BR) and the Eastern Alps (EA) reveals a remarkable parallelism. Both of these Mesozoic-Cenozoic orogenic belts are underlain by sialic crust formed in an earlier Paleozoic orogenic cycle. The old basement is revealed in major tectonic windows: the Tauern Fenster (EA) and the Doonerak Window-Schwatka Mountains (BR) - which are unconformably overlapped by transgressive, neritic marine clastic to carbonate successions - the Permo-Triassic through Hochstegenkalk sequence (EA), and the Kekiktuk-Kayak-Lisburne sequence (BR). These successions are passive-margin sequences that pass southward, in palinspastically restored cross sections, to synchronous deep-water facies deposited on ophiolitic basement - Bunderschiefer on Triassic-Jurassic ophiolites (EA) and Kuna facies or Etivluk sequence on upper Paleozoic ophiolites (BR). Onset of subduction-collision is marked by olistostromal facies - Cretaceous wildflysch (EA) and Jura-Cretaceous Okpikruak Formation (BR) - and the development of major flysch-molasse successions in the foreland basins of the collisional fold and thrust belts. Important major contrasts between these two mountain ranges reside in their colliding blocks and their post-orogenic histories. Alpine orogenesis was driven by continent-continent collision, closing out a young, narrow ocean, whereas Brooks Range deformation appears to have originated by arc-continent collision, closing out an older, broad (.)ocean. Younger Cenozoic deformation is extensional and strike-slip in the Eastern Alps, producing disjunctive basins, but Cenozoic deformation in the Brooks Range is diverse and includes compression in the east and extension in the far west.

  5. Polarized Proton Collisions at RHIC

    CERN Document Server

    Bai, Mei; Alekseev, Igor G; Alessi, James; Beebe-Wang, Joanne; Blaskiewicz, Michael; Bravar, Alessandro; Brennan, Joseph M; Bruno, Donald; Bunce, Gerry; Butler, John J; Cameron, Peter; Connolly, Roger; De Long, Joseph; Drees, Angelika; Fischer, Wolfram; Ganetis, George; Gardner, Chris J; Glenn, Joseph; Hayes, Thomas; Hseuh Hsiao Chaun; Huang, Haixin; Ingrassia, Peter; Iriso, Ubaldo; Laster, Jonathan S; Lee, Roger C; Luccio, Alfredo U; Luo, Yun; MacKay, William W; Makdisi, Yousef; Marr, Gregory J; Marusic, Al; McIntyre, Gary; Michnoff, Robert; Montag, Christoph; Morris, John; Nicoletti, Tony; Oddo, Peter; Oerter, Brian; Osamu, Jinnouchi; Pilat, Fulvia Caterina; Ptitsyn, Vadim; Roser, Thomas; Satogata, Todd; Smith, Kevin T; Svirida, Dima; Tepikian, Steven; Tomas, Rogelio; Trbojevic, Dejan; Tsoupas, Nicholaos; Tuozzolo, Joseph; Vetter, Kurt; Wilinski, Michelle; Zaltsman, Alex; Zelenski, Anatoli; Zeno, Keith; Zhang, S Y

    2005-01-01

    The Relativistic Heavy Ion Collider~(RHIC) provides not only collisions of ions but also collisions of polarized protons. In a circular accelerator, the polarization of polarized proton beam can be partially or fully lost when a spin depolarizing resonance is encountered. To preserve the beam polarization during acceleration, two full Siberian snakes were employed in RHIC to avoid depolarizing resonances. In 2003, polarized proton beams were accelerated to 100~GeV and collided in RHIC. Beams were brought into collisions with longitudinal polarization at the experiments STAR and PHENIX by using spin rotators. RHIC polarized proton run experience demonstrates that optimizing polarization transmission efficiency and improving luminosity performance are significant challenges. Currently, the luminosity lifetime in RHIC is limited by the beam-beam effect. The current state of RHIC polarized proton program, including its dedicated physics run in 2005 and efforts to optimize luminosity production in beam-beam limite...

  6. QCD in heavy ion collisions

    CERN Document Server

    Iancu, Edmond

    2014-01-01

    These lectures provide a modern introduction to selected topics in the physics of ultrarelativistic heavy ion collisions which shed light on the fundamental theory of strong interactions, the Quantum Chromodynamics. The emphasis is on the partonic forms of QCD matter which exist in the early and intermediate stages of a collision -- the colour glass condensate, the glasma, and the quark-gluon plasma -- and on the effective theories that are used for their description. These theories provide qualitative and even quantitative insight into a wealth of remarkable phenomena observed in nucleus-nucleus or deuteron-nucleus collisions at RHIC and/or the LHC, like the suppression of particle production and of azimuthal correlations at forward rapidities, the energy and centrality dependence of the multiplicities, the ridge effect, the limiting fragmentation, the jet quenching, or the dijet asymmetry.

  7. Semiholography for heavy ion collisions

    Science.gov (United States)

    Mukhopadhyay, Ayan; Preis, Florian

    2017-03-01

    The formation of QGP in heavy ion collisions gives us a great opportunity for learning about nonperturbative dynamics of QCD. Semiholography provides a new consistent framework to combine perturbative and non-perturbative effects in a coherent way and can be applied to obtain an effective description for heavy ion collisions. In particular, it allows us to include nonperturbative effects in existing glasma effective theory and QCD kinetic theory for the weakly coupled saturated degrees of freedom liberated by the collisions in the initial stages in a consistent manner. We argue why the full framework should be able to confront experiments with only a few phenomenological parameters and present feasibility tests for the necessary numerical computations. Furthermore, we discuss that semiholography leads to a new description of collective flow in the form of a generalised non-Newtonian fluid. We discuss some open questions which we hope to answer in the near future.

  8. Semiholography for heavy ion collisions

    CERN Document Server

    Mukhopadhyay, Ayan

    2016-01-01

    The formation of QGP in heavy ion collisions gives us a great opportunity for learning about nonperturbative dynamics of QCD. Semiholography provides a new consistent framework to combine perturbative and non-perturbative effects in a coherent way and can be applied to obtain an effective description for heavy ion collisions. In particular, it allows us to include nonperturbative effects in existing glasma effective theory and QCD kinetic theory for the weakly coupled saturated degrees of freedom liberated by the collisions in the initial stages in a consistent manner. We argue why the full framework should be able to confront experiments with only a few phenomenological parameters and present feasibility tests for the necessary numerical computations. Furthermore, we discuss that semiholography leads to a new description of collective flow in the form of a generalised non-Newtonian fluid. We discuss some open questions which we hope to answer in the near future.

  9. Collision Rate Monitors for LHC

    CERN Document Server

    Bravin, E; Burger, S; Byrd, J M; Chow, K; Dutriat, C; Jolliot, M; Lefèvre, T; Matis, H S; Monroy, M; Talanov, V; Turner, W C; Ratti, A; Renet, S

    2007-01-01

    Collision rate monitors are essential in bringing particle beams into collision and optimizing the performances of a collider. In the case of LHC the relative luminosity will be monitored by measuring the flux of small angle neutral particles produced in the collisions. Due to the very different luminosity levels at the four interaction regions (IR) of LHC two different types of monitors have been developed. At the high luminosity IR (ATLAS and CMS) fast ionization chambers will be installed while at the other two (ALICE and LHC-b) solid state polycrystalline Cadmium Telluride (CdTe) detectors will be used. The ionization chambers are being developed by LBNL while the CdTe monitors are being developed by CERN and CEA-LETI.

  10. Timescales in heavy ion collisions

    CERN Document Server

    Lisa, Mike

    2016-01-01

    The study of high energy collisions between heavy nuclei is a field unto itself, distinct from nuclear and particle physics. A defining aspect of heavy ion physics is the importance of a bulk, self-interacting system with a rich space-time substructure. I focus on the issue of timescales in heavy ion collisions, starting with proof from low-energy collisions that femtoscopy can, indeed, measure very long timescales. I then discuss the relativistic case, where detailed measurements over three orders of magnitude in energy reveal a timescale increase that might be due to a first-order phase transition. I discuss also consistency in evolution timescales as determined from traditional longitudinal sizes and a novel analysis using shape information.

  11. Space debris collision and production analytic estimates

    Energy Technology Data Exchange (ETDEWEB)

    Canavan, G.H.

    1996-08-01

    Analytic estimates provide useful estimates of collision rates, fragment production rates, and average collision masses and numbers in good agreement with analytic and numerical estimates for the principal quantities of interest.

  12. Diffractive Bremsstrahlung in Hadronic Collisions

    Directory of Open Access Journals (Sweden)

    Roman Pasechnik

    2015-01-01

    Full Text Available Production of heavy photons (Drell-Yan, gauge bosons, Higgs bosons, and heavy flavors, which is treated within the QCD parton model as a result of hard parton-parton collision, can be considered a bremsstrahlung process in the target rest frame. In this review, we discuss the basic features of the diffractive channels of these processes in the framework of color dipole approach. The main observation is a dramatic breakdown of diffractive QCD factorisation due to the interplay between soft and hard interactions, which dominates these processes. This observation is crucial for phenomenological studies of diffractive reactions in high energy hadronic collisions.

  13. Collision Risk Analysis for HSC

    DEFF Research Database (Denmark)

    Urban, Jesper; Pedersen, Preben Terndrup; Simonsen, Bo Cerup

    1999-01-01

    High Speed Craft (HSC) have a risk profile, which is distinctly different from conventional ferries. Due to different hull building material, structural layout, compartmentation and operation, both frequency and consequences of collision and grounding accidents must be expected to be different from...... conventional ships. To reach a documented level of safety, it is therefore not possible directly to transfer experience with conventional ships. The purpose of this paper is to present new rational scientific tools to assess and quantify the collision risk associated with HSC transportation. The paper...

  14. Collisions in Chiral Kinetic Theory

    CERN Document Server

    Chen, Jing-Yuan; Stephanov, Mikhail A

    2015-01-01

    Using a covariant formalism, we construct a chiral kinetic theory Lorentz invariant to order $\\mathcal O(\\hbar)$ which includes collisions. We find a new contribution to the particle number current due to the side jumps required by the conservation of angular momentum during collisions. We also find a conserved symmetric stress-energy tensor as well as the $H$-function obeying Boltzmann's $H$-theorem. We demonstrate their use by finding a general equilibrium solution and the values of the anomalous transport coefficients characterizing chiral vortical effect.

  15. NA49: lead-lead collision

    CERN Multimedia

    1996-01-01

    This is an image of an actual lead ion collision taken from tracking detectors on the NA49 experiment, part of the heavy ion project at CERN. These collisions produce a very complicated array of hadrons as the heavy ions break up. It is hoped that one of these collisions will eventually create a new state of matter known as quark-gluon plasma.

  16. General characteristics of hadron-hadron collisions

    CERN Document Server

    Kittel, E W

    2004-01-01

    Soft multiparticle production in hadron-hadron collisions is reviewed with particular emphasis on its role as a standard for heavy-ion collisions at SPS and RHIC energies and as a bridge interpolating between the most simple e **+e**- and the most complex AA collisions.

  17. The timing of India-Asia collision onset - facts, theories, controversies

    Science.gov (United States)

    Hu, Xiumian; Garzanti, Eduardo; Wang, Jiangang; Huang, Wentao; An, Wei; Webb, Alex

    2016-04-01

    The timing of initial collision between India and Asia has remained grossly and windingly controversial for half a century. This paper attempts to review this crucial and hotly debated argument, describing first the different methods used to constrain the age of collision and discussing next the rationale, results, inferences and problems associated with each. We conclude that stratigraphy represents the best direct way to unravel collision chronology. Other methods focusing on the magmatic, metamorphic or paleomagnetic record provide additional fundamental constraints, but cannot provide a robust direct estimate of collision onset. Initial collision in the central-eastern Himalaya is dated directly at the Middle Paleocene (59±1 Ma) by the abrupt change in sediment provenance recorded in trench settings (Hu et al., 2015). The quasi-synchronous unconformities documented along both Tethyan passive margin of India and active margin of Asia from Tibet to Zanskar-Ladakh confirm that orogeny was underway at the close of the Paleocene (56 Ma) (Garzanti et al., 1987; Li et al., 2015; Hu et al., 2016), well before the disappearance of marine seaways in the Himalaya during the Eocene (50 Ma) (Najman et al., 2010). Sedimentary evolution and provenance changes in marine to fluvio-deltaic successions are recorded synchronously within error from the western to the central-eastern Himalaya, failing to provide evidence for diachronous collision. These coherent observations are hard to reconcile with three widely cited hypotheses invoking either earlier events of arc-continent collision or ophiolite obduction, or the protracted existence of a Greater India Basin, which should be all rejected after discussing the geological evidence. A scenario no more complex than the one involving solely the passive continental margin of India and the active continental margin of Asia is needed to explain the geological evolution of the nascent Himalaya. The collision between the Tethys

  18. Dijet imbalance in hadronic collisions

    NARCIS (Netherlands)

    Boer, Daniel; Mulders, Piet J.; Pisano, Cristian

    2009-01-01

    The imbalance of dijets produced in hadronic collisions has been used to extract the average transverse momentum of partons inside the hadrons. In this paper we discuss new contributions to the dijet imbalance that could complicate or even hamper this extraction. They are due to polarization of init

  19. High velocity collisions of nanoparticles

    Science.gov (United States)

    Johnson, Donald F.; Mattson, William D.

    2017-01-01

    Nanoparticles (NPs) are a unique class of material with highly functionalizable surfaces and exciting applications. With a large surface-to-volume ratio and potentially high surface tension, shocked nanoparticles might display unique materials behavior. Using density functional theory, we have simulated high-velocity NP collisions under a variety of conditions. NPs composed of diamond-C, cubic-BN, and diamond-Si were considered with particle sizes up to 3.5 nm diameter. Additional simulations involved NPs that were destabilized by incorporating internal strain. The initial spherical NP structures were carved out of bulk crystals while the NPs with internal strain were constructed as a dense core (compressive strain) encompassed by a thin shell (tensile strain). Both on-axis and off-axis collisions were simulated at 10 km/s relative velocity. The amount of internal strain was artificially increased by creating a dense inner core with bond lengths compressed up to 8%. Collision dynamics, shock propagation, and fragmentation will be analyzed, but the simulation are ongoing and results are not finalized. The effect of material properties, internal strain, and collision velocity will be discussed.

  20. Collision Analysis for MS DEXTRA

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Zhang, Shengming

    1999-01-01

    and grounding events have to be analysed and assessed.The present paper outlines such a rational procedure for evaluation of the probabilistic distribution of damages caused by collisions against other ships for a specific ship on a specific route.The work described in the paper constitutes a step towards...

  1. Cern collisions light up Copenhagen

    CERN Multimedia

    Banks, Michael

    2010-01-01

    "Anyone passing by the Niels Bohr Institute in Copenhagen, Denmark, might be startled by some strange moving lights on the facade of the institute's main building. In fact, the dancing beams show, almost in real time, collisions form the Atlas experiment at Cern's Large Hadron Collider (LHC)" (1 paragraph)

  2. Quarkonium production in hadronic collisions

    Energy Technology Data Exchange (ETDEWEB)

    Gavai, R. [Tata Institute for Fundamental Research, Bombay (India); Schuler, G.A.; Sridhar, K. [CERN, Geneva (Switzerland)] [and others

    1995-07-01

    We summarize the theoretical description of charmonium and bottonium production in hadronic collisions and compare it to the available data from hadron-nucleon interactions. With the parameters of the theory established by these data, we obtain predictions for quarkonium production at RHIC and LHC energies.

  3. Outer Dynamics of Ship Collisions

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup

    1996-01-01

    The purpose of these notes is to present analysis procedures for the motion of ships during ship-ship collisions and for ship collisons with offshore structures. The aim is to estimate that part of the lost kinetic energy which will have to be absorbed by rupture and plastic damage of the collidi...

  4. Session: Avian migration and implications for wind power development in the Eastern United States

    Energy Technology Data Exchange (ETDEWEB)

    Mabey, Sarah; Cooper, Brian

    2004-09-01

    This session at the Wind Energy and Birds/Bats workshop consisted of two presentations followed by a discussion/question and answer period. The session was arranged to convey what is known about avian migration, particularly in the eastern US. The first presentation ''Migration Ecology: Issues of Scale and Behavior'' by Sarah Mabey frames the issue of migratory bird interactions with wind energy facilities from an ecological perspective: when, where, and why are migrant bird species vulnerable to wind turbine collision. The second presentation ''Radar Studies of Nocturnal Migration at Wind Sites in the Eastern US'' by Brian Cooper reported on radar studies conducted at wind sites in the eastern US, including Mount Storm, Clipper Wind, and others.

  5. Observation of atomic collisions in crystalline solids

    CERN Document Server

    Nelson, R S; Gevers, R

    2013-01-01

    The Observation of Atomic Collisions in Crystalline Solids presents a critical account of the more important experiments which have provided the basis for a better understanding of atomic collision phenomena in crystalline solids. Collisions have been divided into two artificial regimes; primary collisions which deal with the interaction of the incident particles with the solid, and secondary collisions which deal with those events which occur as a result of lattice atoms recoiling from primary encounters. Although the book is intended principally for the experimentalist some simple theoretica

  6. Eastern Siberia terrain intelligence

    Science.gov (United States)

    ,

    1942-01-01

    The following folio of terrain intelligence maps, charts and explanatory tables represent an attempt to bring together available data on natural physical conditions such as will affect military operations in Eastern Siberia. The area covered is the easternmost section of the U.S.S.R.; that is the area east of the Yenisei River. Each map and accompanying table is devoted· to a specialized set of problems; together they cover such subjects as geology, construction materials, mineral fuels, terrain, water supply, rivers and climate. The data is somewhat generalized due to the scale of treatment as well as to the scarcity of basic data. Each of the maps are rated as to reliability according to the reliability scale on the following page. Considerable of the data shown is of an interpretative nature, although precise data from literature was used wherever possible. The maps and tables were compiled  by a special group from the United States Geological Survey in cooperation with the Intelligence Branch of the Office, Chief of Engineers, War Department.

  7. Photonic, Electronic and Atomic Collisions

    Science.gov (United States)

    Fainstein, Pablo D.; Lima, Marco Aurelio P.; Miraglia, Jorge E.; Montenegro, Eduardo C.; Rivarola, Roberto D.

    2006-11-01

    Plenary. Electron collisions - past, present and future / J. W. McConkey. Collisions of slow highly charged ions with surfaces / J. Burgdörfer ... [et al.]. Atomic collisions studied with "reaction-microscopes" / R. Moshammer ... [et al.]. Rydberg atoms: a microscale laboratory for studying electron-molecule tnteractions / F. B. Dunning -- Collisions involvintg photons. Quantum control of photochemical reaction dynamics and molecular functions / M. Yamaki ... [et al.]. Manipulating and viewing Rydberg wavepackets / R. R. Jones. Angle-resolved photoelectrons as a probe of strong-field interactions / M. Vrakking. Ultracold Rydberg atoms in a structured environment / I. C. H. Liu and J. M. Rost. Synchrotron-radiation-based recoil ion momentum spectroscopy of laser cooled and trapped cesium atoms / L. H. Coutinho. Reconstruction of attosecond pulse trains / Y. Mairesse ... [et al.]. Selective excitation of metastable atomic states by Femto- and attosecond laser pulses / A. D. Kondorskiy. Accurate calculations of triple differential cross sections for double photoionization of the hygrogen molecule / W. Vanroose ... [et al.]. Double and triple photoionization of Li and Be / J. Colgan, M. S. Pindzola and F. Robicheaux. Few/many body dynamics in strong laser fields / J. Zanghellini and T. Brabec. Rescattering-induced effects in electron-atom scattering in the presence of a circularly polarized laser field / A. V. Flegel ... [et al.]. Multidimensional photoelectron spectroscopy / P. Lablanquie ... [et al.]. Few photon and strongly driven transitions in the XUV and beyond / P. Lambropoulos, L. A. A. Nikolopoulos and S. I. Themelis. Ionization dynamics of atomic clusters in intense laser pulses / U. Saalmann and J. M. Rost. On the second order autocorrelation of an XUV attosecond pulse train / E. P. Benis ... [et al.]. Evidence for rescattering in molecular dissociation / I. D. Williams ... [et al.]. Photoionizing ions using synchrotron radiation / R. Phaneuf. Photo double

  8. Problems of the active tectonics of the Eastern Black Sea

    Science.gov (United States)

    Javakhishvili, Z.; Godoladze, T.; Dreger, D. S.; Mikava, D.; Tvaliashvili, A.

    2016-12-01

    The Black Sea Basin is the part of the Arabian Eurasian Collision zone and important unit for understanding the tectonic process of the region. This complex basin comprises two deep basins, separated by the mid-Black Sea Ridge. The basement of the Black Sea includes areas with oceanic and continental crust. It was formed as a "back-arc" basin over the subduction zone during the closing of the Tethys Ocean. In the past decades the Black Sea has been the subject of intense geological and geophysical studies. Several papers were published about the geological history, tectonics, basement relief and crustal and upper mantle structure of the basin. New tectonic schemes were suggested (e. g. Nikishin et al 2014, Shillington et al. 2008, Starostenko et al. 2004 etc.). Nevertheless, seismicity of the Black Sea is poorly studied due to the lack of seismic network in the coastal area. It is considered, that the eastern basin currently lies in a compressional setting associated with the uplift of the Caucasus and structural development of the Caucasus was closely related to the evolution of the Eastern Black Sea Basin. Analyses of recent sequence of earthquakes in 2012 can provide useful information to understand complex tectonic structure of the Eastern Black Sea region. Right after the earthquake of 2012/12/23, National Seismic monitoring center of Georgia deployed additional 4 stations in the coastal area of the country, close to the epicenter area, to monitor aftershock sequence. Seismic activity in the epicentral area is continuing until now. We have relocated approximately 1200 aftershocks to delineate fault scarf using data from Georgian, Turkish and Russian datacenters. Waveforms of the major events and the aftershocks were inverted for the fault plane solutions of the events. For the inversion were used green's functions, computed using new 1D velocity model of the region. Strike-slip mechanism of the major events of the earthquake sequence indicates extensional

  9. Miocene to Recent Magmatism and Geodynamics of Eastern Turkey

    Science.gov (United States)

    Keskin, M.; Sharkov, E. V.; Lebedev, V. A.; Chugaev, A. V.; Oyan, V.; Genc, S. C.; Unal, E.; Aysal, N.

    2012-04-01

    Eastern Turkey has been an active continental collision zone for the last 15 My between the African and Eurasian continents. The collision started at around 15 Ma after the total consumption of oceanic lithosphere of the southern branch of the Neotethys Ocean beneath E Anatolia and is still going on, as Africa still converges to E Anatolia with a velocity of ~2.5 cm/y. The overriding Anatolian plate, resided below the sea level till the collision, was subjected to a major block uplift event around 10 Ma, emerging as a widespread plateau ~2 km above the sea level, which has been roughened by later erosion and volcanic activities. The aforementioned plateau is considered as part of a regional dome structure with ~1000 km diameter extending from E Anatolia up to Azerbaijan. Immediately after the collision, a widespread volcanism emerged on the Eastern Anatolian Plateau, whose products covered almost over half of the region. Characteristically, all these products contain a distinct subduction component. The volcanism in the collision zone continued to the historical times and is considered to be still active. The region includes some of the largest volcanic centers (e.g. Ararat, Nemrut, Tendürek and Süphan volcanoes) and plateaus (e.g. The Erzurum-Kars Plateau) around the circum-Mediterranean region. The collision-related volcanic province is not only confined into Anatolia but also continues into the neighboring countries through Georgia, Armenia, Iran and up to Russia, spanning ~1000 km. In contrast, the underthrusting Arabian platform was subjected to both crustal-scale east-west folding close to the thrust front and extensional deformations perpendicular to the suture zone. Along these extensional fractures, within-plate lavas with no subduction component erupted. This intraplate volcanism focused on the Karacadağ volcanic complex, covering an area ~10,000 km2. Early Stage volcanism of Karacadağ was dominated by magmas derived from a shallower (litospheric

  10. Collisions engineering. Theory and applications

    Energy Technology Data Exchange (ETDEWEB)

    Fremond, Michel [Rome ' ' Tor Vergata' ' Univ. (Italy). Dept. of Civil Engineering and Computer Science

    2017-02-01

    This book investigates collisions occurring in the motion of solids, in the motion of fluids but also in the motion of pedestrians in crowds. The duration of these presented collisions is short compared to the whole duration of the motion: they are assumed instantaneous. The innovative concept demonstrated in this book is that a system made of two solids, is deformable because their relative position changes. The definition of the velocities of deformation of the system introduced in the classical developments of mechanics, the principle of the virtual work and the laws of thermodynamics, allows a large range of applications such as crowd motions, debris flow motions, and shape memory alloys motions. The set of the applications is even larger: social sciences and mechanics are unified to predict the motion of crowds with application to transport management and to evacuation of theaters management.

  11. Collisions engineering theory and applications

    CERN Document Server

    Frémond, Michel

    2017-01-01

    This book investigates collisions occurring in the motion of solids, in the motion of fluids but also in the motion of pedestrians in crowds. The duration of these presented collisions is short compared to the whole duration of the motion: they are assumed instantaneous. The innovative concept demonstrated in this book is that a system made of two solids, is deformable because their relative position changes. The definition of the velocities of deformation of the system introduced in the classical developments of mechanics, the principle of the virtual work and the laws of thermodynamics, allows a large range of applications such as crowd motions, debris flow motions, and shape memory alloys motions. The set of the applications is even larger: social sciences and mechanics are unified to predict the motion of crowds with application to transport management and to evacuation of theaters management.

  12. A present-day tectonic stress map for eastern Asia region

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the data of earthquake centroid moment tensor (CMT) solution, P-wave first motion focal mechanism solution and deep hole breakouts, a present-day tectonic stress map for eastern Asia region is compiled. The origi-nal stress data are smoothed for every 200 km ′ 200 km area by taking the average of all stress indicators within each sub-region. The stress map shows the spatial distribution of the orientation of principal stress axes and the stress regimes. An earthquake focal mechanism map for the eastern Asia is also given. The maps of orientation of principal stress axes show that, apart from the strong influence of the collision between the Indian Ocean plate and Eurasian plate, the present-day tectonic stress in eastern Asia is significantly affected by the back-arc extension of the subduction zones. The joint effect of the continental collision at the Himalaya arc and back-arc extension in the Burma arc region may be responsible for the remarkable rotation of the principal stress orientations in southeastern part of the Tibet plateau. The joint action of the collision between the Philippine Sea plate and Eurasian plate at Taiwan Island and the back-arc extension of the Ryukyu arc affect the stress field in eastern part of China. There are no strong earthquakes in the present day in the vast back-arc region of the Java trench subduction zone. The back-arc extension there may create a condition favorable to the southward flow of the lithosphere material in southeastern Asia. In the inner part of the Tibet plateau region, roughly demarcated by the Kunlun mountain, the northern and northeastern part is a broad intracontinental compressive zone, while the southern and southwestern part is generally in a normal-faulting stress state.

  13. The Automatic Galaxy Collision Software

    CERN Document Server

    Smith, Beverly J; Pfeiffer, Phillip; Perkins, Sam; Barkanic, Jason; Fritts, Steve; Southerland, Derek; Manchikalapudi, Dinikar; Baker, Matt; Luckey, John; Franklin, Coral; Moffett, Amanda; Struck, Curtis

    2009-01-01

    The key to understanding the physical processes that occur during galaxy interactions is dynamical modeling, and especially the detailed matching of numerical models to specific systems. To make modeling interacting galaxies more efficient, we have constructed the `Automatic Galaxy Collision' (AGC) code, which requires less human intervention in finding good matches to data. We present some preliminary results from this code for the well-studied system Arp 284 (NGC 7714/5), and address questions of uniqueness of solutions.

  14. Do Speed Cameras Reduce Collisions?

    OpenAIRE

    Skubic, Jeffrey; Johnson, Steven B.; Salvino, Chris; Vanhoy, Steven; Hu, Chengcheng

    2013-01-01

    We investigated the effects of speed cameras along a 26 mile segment in metropolitan Phoenix, Arizona. Motor vehicle collisions were retrospectively identified according to three time periods – before cameras were placed, while cameras were in place and after cameras were removed. A 14 mile segment in the same area without cameras was used for control purposes. Five cofounding variables were eliminated. In this study, the placement or removal of interstate highway speed cameras did not indepe...

  15. Central collisions of heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Fung, Sun-yiu.

    1992-10-01

    This report describes the activities of the Heavy Ion Physics Group at the University of California, Riverside from October 1, 1991 to September 30, 1992. During this period, the program focused on particle production at AGS energies, and correlation studies at the Bevalac in nucleus-nucleus central collisions. As part of the PHENIX collaboration, contributions were made to the Preliminary Conceptual Design Report (pCDR), and work on a RHIC silicon microstrip detector R D project was performed.

  16. Gravitational waves from cosmic bubble collisions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-Hoon [Ewha Womans University, Basic Science Research Institute, Seoul (Korea, Republic of); Ewha Womans University, Institute for the Early Universe, Seoul (Korea, Republic of); Lee, Bum-Hoon [Sogang University, Center for Quantum Spacetime, Seoul (Korea, Republic of); Sogang University, Department of Physics, Seoul (Korea, Republic of); Lee, Wonwoo [Sogang University, Center for Quantum Spacetime, Seoul (Korea, Republic of); Yang, Jongmann [Ewha Womans University, Basic Science Research Institute, Seoul (Korea, Republic of); Ewha Womans University, Institute for the Early Universe, Seoul (Korea, Republic of); Ewha Womans University, Department of Physics, Seoul (Korea, Republic of); Yeom, Dong-han [Sogang University, Center for Quantum Spacetime, Seoul (Korea, Republic of); Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan); National Taiwan University, Leung Center for Cosmology and Particle Astrophysics, Taipei (China)

    2015-03-01

    Cosmic bubbles are nucleated through the quantum tunneling process. After nucleation they would expand and undergo collisions with each other. In this paper, we focus in particular on collisions of two equal-sized bubbles and compute gravitational waves emitted from the collisions. First, we study the mechanism of the collisions by means of a real scalar field and its quartic potential. Then, using this model, we compute gravitational waves from the collisions in a straightforward manner. In the quadrupole approximation, time-domain gravitational waveforms are directly obtained by integrating the energy-momentum tensors over the volume of the wave sources, where the energy-momentum tensors are expressed in terms of the scalar field, the local geometry and the potential. We present gravitational waveforms emitted during (i) the initial-to-intermediate stage of strong collisions and (ii) the final stage of weak collisions: the former is obtained numerically, in full General Relativity and the latter analytically, in the flat spacetime approximation. We gain qualitative insights into the time-domain gravitational waveforms from bubble collisions: during (i), the waveforms show the non-linearity of the collisions, characterized by a modulating frequency and cusp-like bumps, whereas during (ii), the waveforms exhibit the linearity of the collisions, featured by smooth monochromatic oscillations. (orig.)

  17. QCD studies in ep collisions

    Energy Technology Data Exchange (ETDEWEB)

    Smith, W.H. [Univ. of Wisconsin, Madison, WI (United States). Physics Dept.

    1997-06-01

    These lectures describe QCD physics studies over the period 1992--1996 from data taken with collisions of 27 GeV electrons and positrons with 820 GeV protons at the HERA collider at DESY by the two general-purpose detectors H1 and ZEUS. The focus of these lectures is on structure functions and jet production in deep inelastic scattering, photoproduction, and diffraction. The topics covered start with a general introduction to HERA and ep scattering. Structure functions are discussed. This includes the parton model, scaling violation, and the extraction of F{sub 2}, which is used to determine the gluon momentum distribution. Both low and high Q{sup 2} regimes are discussed. The low Q{sup 2} transition from perturbative QCD to soft hadronic physics is examined. Jet production in deep inelastic scattering to measure {alpha}{sub s}, and in photoproduction to study resolved and direct photoproduction, is also presented. This is followed by a discussion of diffraction that begins with a general introduction to diffraction in hadronic collisions and its relation to ep collisions, and moves on to deep inelastic scattering, where the structure of diffractive exchange is studied, and in photoproduction, where dijet production provides insights into the structure of the Pomeron. 95 refs., 39 figs.

  18. Infanticide in Eastern Croatia.

    Science.gov (United States)

    Marcikić, Mladen; Dumencić, Boris; Matuzalem, Elizabeta; Marjanović, Ksenija; Pozgain, Ivan; Ugljarević, Mladen

    2006-06-01

    For the layperson no crime is more difficult to comprehend than the killing of a child by his or her own parents. This is a retrospective study of neonaticide and infanticide in Eastern Croatia from 1980 to 2004. Judicial records of infanticide cases stored in Regional and County Courts were analyzed for the circumstances surrounding the offense. Twenty-four babies were discovered in various places during investigating period of time. The victims were almost equally divided between boys (12) and girls (11). The gender of one baby was unknown. The mean weight of babies was 2.7 SD = 0.66 kg. The perpetrators preferred rubbish-heaps (33.4%), burying in soil (16.7%), various premises in or around the house (16.7%) and garbage cans (12.5%) as places for hiding the dead babies. The most dominant cause of death in sixteen cases of live birth was asphyxia (37%) with equal distribution of smothering, stuffing the mouth with rags and strangulation. Other frequent causes of death were placing the child in a plastic bag and abandonment (25%), brain injury (25%) and wounding using a sharp weapon (12.5%). The cause of death for six babies remained unknown due to advanced decomposition. Two babies were stillborn. The age of accused mothers varied from 16 to 33, mean 24 SD=5.2 years. Most of them were unmarried (60%) and had limited formal education. They usually kept the pregnancy a secret (73%) and gave birth (93%) without public welfare assistance. The mother lived in the terror of shame and with the guilt that accompany conception without marriage. Fear seemed to be a pronounced motivating factor for committing infanticide. The data on court proceedings were available in fifteen cases. The mothers were officially indicted in all cases for infanticide under the Croatian Criminal Code. The perpetrator remained unidentified in nine suspicious crimes. The court convicted ten mothers of the crime of infanticide. Often juries were unwilling to punish the mother, citing the mother

  19. Planetesimal collisions as a chondrule forming event

    CERN Document Server

    Wakita, Shigeru; Oshino, Shoichi; Hasegawa, Yasuhiro

    2016-01-01

    Chondritic meteorites contain unique spherical materials named chondrules: sub-mm sized silicate grains once melted in a high temperature condition in the solar nebula. We numerically explore one of chondrule forming processes, planetesimal collisions. Previous studies found that impact jetting via protoplanet-planetesimal collisions make chondrules with an amount of 1 % of impactors' mass, when impact velocity exceeds 2.5 km s$^{-1}$. Based on the mineralogical data of chondrules, undifferentiated planetesimals would be more suitable for chondrule-forming collisions than potentially differentiated protoplanets. We examine planetesimal-planetesimal collisions using a shock physics code and find two things: one is that planetesimal-planetesimal collisions produce the nearly same amount of chondrules as protoplanet-planetesimal collisions ($\\sim$ 1 %). The other is that the amount of produced chondrules becomes larger as the impact velocity increases when two planetesimals collide with each other. We also find ...

  20. The Concept of Collision-Free Motion Planning Using a Dynamic Collision Map

    Directory of Open Access Journals (Sweden)

    Keum-Bae Cho

    2014-09-01

    Full Text Available In this paper, we address a new method for the collision-free motion planning of a mobile robot in dynamic environments. The motion planner is based on the concept of a conventional collision map (CCM, represented on the L(travel length-T(time plane. We extend the CCM with dynamic information about obstacles, such as linear acceleration and angular velocity, providing useful information for estimating variation in the collision map. We first analyse the effect of the dynamic motion of an obstacle in the collision region. We then define the measure of collision dispersion (MOCD. The dynamic collision map (DCM is generated by drawing the MOCD on the CCM. To evaluate a collision-free motion planner using the DCM, we extend the DCM with MOCD, then draw the unreachable region and deadlocked regions. Finally, we construct a collision-free motion planner using the information from the extended DCM.

  1. A model for collisions in granular gases

    OpenAIRE

    Brilliantov, Nikolai V.; Spahn, Frank; Hertzsch, Jan-Martin; Poeschel, Thorsten

    2002-01-01

    We propose a model for collisions between particles of a granular material and calculate the restitution coefficients for the normal and tangential motion as functions of the impact velocity from considerations of dissipative viscoelastic collisions. Existing models of impact with dissipation as well as the classical Hertz impact theory are included in the present model as special cases. We find that the type of collision (smooth, reflecting or sticky) is determined by the impact velocity and...

  2. Eastern Orthodox perspectives on violence

    DEFF Research Database (Denmark)

    Hilton Saggau, Emil

    2017-01-01

    Abstract: In the post-communist era, the contemporary national Eastern Orthodox churches have often been accused of taking either direct or ideological part in violence across Eastern Europe. In several scholarly analyses, the churches have been linked with ethnic and national violence. They have...... thus been identified as an ideological root for a distinctive ethno-religious nationalism either blocking the way for a pluralistic society or simply defying it. These cases of violence and conflicts, as well as their subsequent analysis, only point to a practical and visible manifestation of conflicts......, and they therefore don’t answer a broader theological question, namely the question of the general position of the Eastern Orthodox churches regarding violence. This article will address this broader question of what the Orthodox churches’ position is on violence and discuss the co-relation and intersection between...

  3. Ionization in collisions between metastable hydrogen atoms

    Science.gov (United States)

    Bohr, Alex; Blickle, Andrew; Paolini, Stephen; Ohlinger, Luke; Forrey, Robert

    2012-06-01

    Associative and Penning ionization cross sections are calculated for collisions between metastable hydrogen 2s atoms at thermal energies. Cross sections for deuterium 2s collisions are also reported. The associative ionization cross sections behave as E-1 for collision energy E, in agreement with an existing experiment. The Penning ionization cross sections dominate for all energies and are found to follow the E-2/3 behavior that was predicted in previous work for the total ionization cross section. The magnitudes of our theoretical associative ionization cross sections for H(2s)+H(2s) collisions are between two and four times larger than the experimental data.

  4. Ultrarelativistic nuclear collisions: Direction of spectator flow

    Science.gov (United States)

    Voloshin, Sergei A.; Niida, Takafumi

    2016-08-01

    In high-energy heavy-ion collisions, the directed flow of particles is conventionally measured with respect to that of the projectile spectators, which is defined as positive x direction, but it is not known if the spectators deflect in the outward or inward directions—outward or toward the center line of the collision. In this Communication we discuss how the measurements of the directed flow at midrapidity, especially in asymmetric collision such as Cu +Au , can be used to answer this question. We show that the existing data strongly favor the case that the spectators, in the ultrarelativistic collisions, on average deflect outward.

  5. Telerobotics with whole arm collision avoidance

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelmsen, K.; Strenn, S.

    1993-09-01

    The complexity of teleorbotic operations in a cluttered environment is exacerbated by the need to present collision information to the operator in an understandable fashion. In addition to preventing movements which will cause collisions, a system providing some form of virtual force reflection (VFR) is desirable. With this goal in mind, Lawrence Livermore National Laboratory (LLNL) has installed a kinematically master/slave system and developed a whole arm collision avoidance system which interacts directly with the telerobotic controller. LLNL has also provided a structure to allow for automated upgrades of workcell models and provide collision avoidance even in a dynamically changing workcell.

  6. Regional Development of Eastern Slovakia

    Directory of Open Access Journals (Sweden)

    Monika Hergezelová

    2017-08-01

    Full Text Available Purpose and Originality: The aim of the work is to provide an overview of regional development in Eastern Slovakia, where are Košice and Prešov Region. The originality of the work lies in the work of enriching the SWOT analysis from the author Eve Rajčáková, which is given in the book deals with the issue of Regional development and regional policy of the European Union and Slovakia. Research question: The conditions of life of people in eastern Slovakia. Method: For writing this contribution will be used method of analysis and statistics. Knowledge on this subject have been looking on the internet and in books and sources of information publicly available. Using the data collected, we dealt with the issue of regional development in the Košice and Prešov regions. Results: The topic was the beginning focused on the overall characteristics of eastern Slovakia. Furthermore, we are at work we dealt with social and economic phenomena in both regions of eastern Slovakia. We focused on GDP, unemployment and tourism, which is in the region is widespread. Society: It is well known that there are obviously different living conditions in eastern Slovakia as in other parts of Slovakia. People are forced to, mainly because of employment, leave their region to move or commute to work to the west. The paper point out the right of this negative phenomenon that is quite visible - high unemployment. Limitations: The limits of work are limited by problems of regional development in eastern Slovakia, mainly focusing on economic and social phenomena in the society.

  7. The Collision Timing and Subsequent Deformation Phases in the Western Himalaya during the India-Eurasia Collision

    Science.gov (United States)

    Jagoutz, O.; Upadhyay, R.; Bouilhol, P.; Van Buer, N. J.; Hanchar, J. M.

    2012-12-01

    The western Himalaya differ from the central and eastern Himalaya due to the presence of the Kohistan-Ladakh paleo Island arc (KLA) that separates India from the former Eurasian margin (e.g. Karakoram). The KLA is separated from India by the Indus suture zone in the south, and in the north by the Shyok suture zone from the Karakorum. In an effort to understand the complicated collisional history in the western Himalaya we mapped ~8000 km2 in the western Himalaya in India over the last 4 years, focusing in detail on the intersection of the Shyok suture zone and the Karakoram fault. These results in combination with our previous work and published results from the western Himalaya in Pakistan, and U-Pb Zircon geochronology allows us to constrain the collisional history related to the India-Eurasia collision of this poorly studied region of the Himalayas. Our mapping indicate that the western Himalaya in India is dominated by four major fault zones: (1) the north dipping Indus suture, previously dated at 50 Ma; (2) the Shyok suture an originally south dipping fault zone of essentially unknown age; (3) a north dipping thrusts and reverse fault system likely the equivalent of the Karakoram thrust system described from northern Pakistan; and finally (4) the dextral Karakorum strike-slip fault. The continental Saltoro Molasse composed of conglomerate and sandstones is generally spatially associated in our mapping area with the Shyok suture zone and likely the western equivalent of the Purit formation described in Pakistan. The deposition of the Saltoro molasses postdated the formation of the Shyok suture zones, as serpentinized ultramafic conglomerate clasts are common in the molasse and are likely derived from the near-by ultramafics of the Shyok suture zone. However, both the Shyok suture and the Saltoro molasse are affected by the thrusting along the Karakoram thrust system and the deformation associated with movement of the Karakoram fault. These relative age

  8. Wave speed structure of the eastern North American margin

    Science.gov (United States)

    Savage, B.; Covellone, B. M.; Shen, Y.

    2017-02-01

    The eastern North American margin (ENAM) is the result of nearly a billion years of continental collision and rifting. To the west of this margin lies thick continental lithosphere of the North American craton, and to the east is oceanic lithosphere in the Atlantic. The substantial changes in lithosphere thickness at this boundary are thought to drive asthenosphere upwelling along the edge of the continent. Through iterative, full-waveform, ambient noise tomography, we observe a heterogeneous low wave speed margin along the continent in the upper mantle. Multiple low wave speed features imaged within the margin are consistent with asthenospeheric upwelling due to edge-driven convection. Also within the margin are high wave speed anomalies that maybe the remnants of eclogitic delamination of the Appalachian crustal root, which contribute to convection at the margin. Edge driven, small-scale convection keeps the margin weak and thus controls the large scale plate tectonic patterns and the crustal deformation. The imaged mantle wave speed anomalies, interpreted as edge-driven convection, correlate with and may increase the likelihood of damaging earthquakes in the eastern portion of North America.

  9. Western juniper in eastern Oregon.

    Science.gov (United States)

    Donald R. Gedney; David L. Azuma; Charles L. Bolsinger; Neil. McKay

    1999-01-01

    This report analyzes and summarizes a 1988 inventory of western juniper (Juniperus occidentalis Hook.) in eastern Oregon. This inventory, conducted by the Pacific Northwest Research Station of the USDA Forest Service, was intensified to meet increased need for more information about the juniper resource than was available in previous inventories. A...

  10. Citizenship Norms in Eastern Europe

    Science.gov (United States)

    Coffe, Hilde; van der Lippe, Tanja

    2010-01-01

    Research on Eastern Europe stresses the weakness of its civil society and the lack of political and social involvement, neglecting the question: What do people themselves think it means to be a good citizen? This study looks at citizens' definitions of good citizenship in Poland, Slovenia, the Czech Republic and Hungary, using 2002 European Social…

  11. Citizenship norms in Eastern Europe

    NARCIS (Netherlands)

    Coffé, H.R.; Lippe, T. van der

    2010-01-01

    Research on Eastern Europe stresses the weakness of its civil society and the lack of political and social involvement, neglecting the question: What do people themselves think it means to be a good citizen? This study looks at citizens’ definitions of good citizenship in Poland, Slovenia, the Czech

  12. Citizenship norms in Eastern Europe

    NARCIS (Netherlands)

    Coffé, H.R.; Lippe, T. van der

    2010-01-01

    Research on Eastern Europe stresses the weakness of its civil society and the lack of political and social involvement, neglecting the question: What do people themselves think it means to be a good citizen? This study looks at citizens’ definitions of good citizenship in Poland, Slovenia, the Czech

  13. Currency substitution in Eastern Europe

    NARCIS (Netherlands)

    van Aarle, B.; Budina, N.

    1995-01-01

    Monetary instability during the transition process from a command economy to a market economy has induced a considerable increase in currency substitution in Eastern Europe. Currency substitution itself affects monetary stability since it reduces the stability of velocity. This paper investigates cu

  14. Astroparticle Physics at Eastern Colombia

    CERN Document Server

    Asorey, Hernan

    2015-01-01

    We present the emerging panorama of Astroparticle Physics at Eastern Colombia, and describe several ongoing projects, most of them related to the Latin American Giant Observatory (LAGO) Project. This research work is carried out at the Grupo de Investigaciones en Relatividad y Gravitaci\\'on of Universidad Industrial de Santander.

  15. Anthracnose Diseases of Eastern Hardwoods

    Science.gov (United States)

    Frederick H. Berry

    1985-01-01

    Anthracnose diseases of hardwood trees are widespread throughout the Eastern United States. The most common symptom of these diseases is dead areas or blotches on the leaves. Because of the brown and black, scorched appearance of the leaves, the diseases are sometimes called leaf blight.

  16. Fate of an Oceanic Island-arc at the Collision Zone: Insight From a Modern Case at the Izu Collision Zone, Central Japan

    Science.gov (United States)

    Aoike, K.

    2003-12-01

    Arc-arc or arc-continent collision zone, which separates an arc crust into materials to be left on the earth_fs surface and to be returned to the mantle, is regarded as the final disposal place of the subduction factory product. Mass balance across the collision boundary, therefore, should have great significance in the processes of continental growth and mantle evolution. The Izu Collision Zone (ICZ) located at the conjunction of the Honshu arc and the Izu-Bonin arc (IBA), is a place of ongoing orthogonal arc-arc collision, where the middle to upper crust of the northern IBA is exposed on land as accretionary terranes. The IBA-ICZ system is much advantageous for elucidating the mass balance, because that the product is simple and fresh and the flow from manufacture to disposal is quite clear. Across arc variation of buoyancy and rheological state of the lithosphere controlled principally by geothermal gradient would regulate the regime of collision tectonics. Crust-scale accretion is taking place associated with conspicuous crustal shortening and thickening in the central ICZ where the active arc that is about 100 km wide and 20 km thick is colliding. By contrast, almost the whole arc crust is subducting, leaving the off-scraped sediments as accretionary prisms in the eastern and western areas where the inactive forearc and backarc, totally 200 km wide and averagely 14 km thick, are colliding. Based on the land geology and existing seismic structure, crustal volume of the accreted IBA is estimated for the line along the axis of the ICZ and another line passing through the Tanzawa Terrane situated eastward 30 km apart from the axis. The estimation indicates that the volume of the Tanzawa line is significantly smaller (16 %) than that of the axis, in spite of being very close. This difference is explainable, if the Philippine Sea Plate slab including expected aseismic part is accompanied with 7 km thick subducted arc crust. This result of calculation implies that

  17. Mechanical Energy Changes in Perfectly Inelastic Collisions

    Science.gov (United States)

    Mungan, Carl E.

    2013-01-01

    Suppose a block of mass "m"[subscript 1] traveling at speed "v"[subscript 1] makes a one-dimensional perfectly inelastic collision with another block of mass "m"[subscript 2]. What else does one need to know to calculate the fraction of the mechanical energy that is dissipated in the collision? (Contains 1 figure.)

  18. Cultural Collisions in L2 Academic Writing.

    Science.gov (United States)

    Steinman, Linda

    2003-01-01

    Reviews research on writing and culture, focusing on the collisions of cultures when discourse practices second language writers are expected to reproduce clash with what they know, believe, and value in their first language writing. Describes collisions of culture in writing regarding voice, organization, reader/writer responsibility, topic, and…

  19. Long-Range Collisions in Magnetized Plasmas

    Science.gov (United States)

    Dubin, D.

    2015-12-01

    Astrophysical (and earthbound) plasmas in strong magnetic fields exhibit collisional effects that are not described by classical collision theory nor by the standard collision operators, such as the Landau or Balescu-Lenard operators. These theories implicitly neglect "long-range" collisions, i.e. collisions with impact parameters large compared to the cyclotron radius. This presentation will review several important physical effects such collisions have on various phenomena, including cross-magnetic field diffusion, heat conduction, and collisional slowing parallel to the magnetic field. Long-range collisions are analyzed as guiding-centers moving in one-dimension along the magnetic field, with parallel energy and momentum transferred to particles on separate field lines through the screened Coulomb interaction. This causes cross-field heat transport that is independent of magnetic field strength B (as opposed to the classical 1/B2 scaling), and enhances the rate of collisional slowing parallel to B. The Coulomb interaction between guiding centers on different field lines also produces random ExB drifts that enhance cross-magnetic field diffusion compared to the classical theory. The theory of long-range guiding center collisions must also include the novel effect of "collisional caging": plasma noise causes two colliding guiding centers to diffuse in relative parallel velocity, reversing their motion along B and colliding several times before becoming uncorrelated. This further enhances cross-field diffusion from long-range collisions by a factor of three, and enhances parallel slowing by a factor of approximately 1.5.

  20. Freestart collision for full SHA-1

    NARCIS (Netherlands)

    Stevens, M.M.J.; Karpman, P.; Peyrin, T.

    2015-01-01

    We present in this article a freestart collision example for SHA-1, i.e., a collision for its internal compression function. This is the first practical break of the full SHA-1, reaching all 80 out of 80 steps, while only 10 days of computation on a 64 GPU cluster were necessary to perform the attac

  1. Lambda Polarization in Lead-Lead Collisions

    NARCIS (Netherlands)

    Schillings, Eelco

    2003-01-01

    In this thesis the production and polarization of Lambda particles produced in Pb-Pb collisions at a beam energy of 158 GeV/c per nucleon are studied. In these collisions nuclear matter is compressed and heated and under these conditions it is possible that a quark-gluon plasma (QGP) is created. In

  2. Distraction-related road traffic collisions

    African Journals Online (AJOL)

    drivers at the collision time over one and half years. Driver's inattentive ... drivers involved in road traffic collisions (RTC) were using mobile phones. Our study supports .... two groups in age, gender, nationality, seat belt usage, or death on the ...

  3. Theory and Validation for the Collision Module

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup

    1999-01-01

    This report describes basic modelling principles, the theoretical background and validation examples for the Collision Module for the computer program DAMAGE.......This report describes basic modelling principles, the theoretical background and validation examples for the Collision Module for the computer program DAMAGE....

  4. Collision risk management in geosynchronous orbit

    Science.gov (United States)

    Jenkin, A. B.; Peterson, G. E.

    2004-01-01

    A systematic method has been developed for managing long-term collision risk posed to operational satellites in geosynchronous orbit. Long-term collision risk reduction is achieved by proper selection of local collision probability thresholds that trigger actions to reduce risk. Such actions can be requests for more accurate orbital data, special sensor tasking, or collision avoidance maneuvers. The cost of collision risk reduction is measured by the frequency of actions taken to reduce the collision risk. This action frequency is dependent on the accuracy of the orbital data and the frequency of close approaches. A case study was performed for a set of satellites. The analysis used position error models for two-line element sets. A conjunction simulation was used to process approximately three years of archived orbital data, including publicly available two-line element sets, in order to generate conjunction statistics. From these results, a graphical representation called a χ-plot was generated. This plot permits the selection of thresholds as a function of total risk reduction and tolerable action frequency. Results of the study indicate that collision risk management in geosynchronous orbit can be very costly using data of insufficiently high accuracy, because data errors induce high action frequency for even modest amounts of collision risk reduction.

  5. Positron collisions with alkali-metal atoms

    Science.gov (United States)

    Gien, T. T.

    1990-01-01

    The total cross sections for positron and electron collisions with potassium, sodium, lithium and rubidium are calculated, employing the modified Glauber approximation. The Modified Glauber cross sections for positron collision with potassium and sodium at low intermediate energies are found to agree reasonably well with existing experimental data.

  6. Z to Muon Muon Collision Event Animation

    CERN Multimedia

    ATLAS experiment

    2010-01-01

    This animation was created of an actual ATLAS collision event in 2010. This animation shows from the particle view the race through the LHC, ending in the detector where the particle collision occurs. Candidate for an event with a Z boson decaying to two muons.

  7. Ground Collision Avoidance System (Igcas)

    Science.gov (United States)

    Skoog, Mark A (Inventor); Prosser, Kevin (Inventor); Hook, Loyd (Inventor)

    2017-01-01

    The present invention is a system and method for aircraft ground collision avoidance (iGCAS) comprising a modular array of software, including a sense own state module configured to gather data to compute trajectory, a sense terrain module including a digital terrain map (DTM) and map manger routine to store and retrieve terrain elevations, a predict collision threat module configured to generate an elevation profile corresponding to the terrain under the trajectory computed by said sense own state module, a predict avoidance trajectory module configured to simulate avoidance maneuvers ahead of the aircraft, a determine need to avoid module configured to determine which avoidance maneuver should be used, when it should be initiated, and when it should be terminated, a notify Module configured to display each maneuver's viability to the pilot by a colored GUI, a pilot controls module configured to turn the system on and off, and an avoid module configured to define how an aircraft will perform avoidance maneuvers through 3-dimensional space.

  8. Fixed Target Collisions at STAR

    Science.gov (United States)

    Meehan, Kathryn C.

    2016-12-01

    The RHIC Beam Energy Scan (BES) program was proposed to look for the turn-off of signatures of the quark gluon plasma (QGP), search for a possible QCD critical point, and study the nature of the phase transition between hadronic and partonic matter. Previous results have been used to claim that the onset of deconfinement occurs at a center-of-mass energy of 7 GeV. Data from lower energies are needed to test if this onset occurs. The goal of the STAR Fixed-Target Program is to extend the collision energy range in BES II to energies that are likely below the onset of deconfinement. Currently, STAR has inserted a gold target into the beam pipe and conducted test runs at center-of-mass energies of 3.9 and 4.5 GeV. Tests have been done with both Au and Al beams. First physics results from a Coulomb potential analysis of Au + Au fixed-target collisions are presented and are found to be consistent with results from previous experiments. Furthermore, the Coulomb potential, which is sensitive to the Z of the projectile and degree of baryonic stopping, will be compared to published results from the AGS.

  9. Holographic collisions in confining theories

    CERN Document Server

    Cardoso, Vitor; Mateos, David; Pani, Paolo; Rocha, Jorge V

    2013-01-01

    We study the gravitational dual of a high-energy collision in a confining gauge theory. We consider a linearized approach in which two point particles traveling in an AdS-soliton background suddenly collide to form an object at rest (presumably a black hole for large enough center-of-mass energies). The resulting radiation exhibits the features expected in a theory with a mass gap: late-time power law tails of the form t^(-3/2), the failure of Huygens' principle and distortion of the wave pattern as it propagates. The energy spectrum is exponentially suppressed for frequencies smaller than the gauge theory mass gap. Consequently, we observe no memory effect in the gravitational waveforms. At larger frequencies the spectrum has an upward-stairway structure, which corresponds to the excitation of the tower of massive states in the confining gauge theory. We discuss the importance of phenomenological cutoffs to regularize the divergent spectrum, and the aspects of the full non-linear collision that are expected ...

  10. Simulating Collisions for Hydrokinetic Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Richmond, Marshall C.; Romero Gomez, Pedro DJ; Rakowski, Cynthia L.

    2013-10-01

    Evaluations of blade-strike on an axial-flow Marine Hydrokinetic turbine were conducted using a conventional methodology as well as an alternative modeling approach proposed in the present document. The proposed methodology integrates the following components into a Computa- tional Fluid Dynamics (CFD) model: (i) advanced eddy-resolving flow simulations, (ii) ambient turbulence based on field data, (iii) moving turbine blades in highly transient flows, and (iv) Lagrangian particles to mimic the potential fish pathways. The sensitivity of blade-strike prob- ability to the following conditions was also evaluated: (i) to the turbulent environment, (ii) to fish size and (iii) to mean stream flow velocity. The proposed methodology provided fraction of collisions and offered the capability of analyzing the causal relationships between the flow envi- ronment and resulting strikes on rotating blades. Overall, the conventional methodology largely overestimates the probability of strike, and lacks the ability to produce potential fish and aquatic biota trajectories as they interact with the rotating turbine. By using a set of experimental corre- lations of exposure-response of living fish colliding on moving blades, the occurrence, frequency and intensity of the particle collisions was next used to calculate the survival rate of fish crossing the MHK turbine. This step indicated survival rates always greater than 98%. Although the proposed CFD framework is computationally more expensive, it provides the advantage of evaluating multiple mechanisms of stress and injury of hydrokinetic turbine devices on fish.

  11. Language in Education in Eastern Africa.

    Science.gov (United States)

    Gorman, T. P., Ed.

    This volume contains the papers given at the first Eastern Africa Conference on Language and Linguistics, held in Dar es Salaam in December 1968, under the auspices of the Survey of Language Use and Language Teaching in Eastern Africa. The chief aim of the Conference was to bring together scholars and teachers working in Eastern Africa interested…

  12. The epidemiology of bicyclist's collision accidents

    DEFF Research Database (Denmark)

    Larsen, L. B.

    1994-01-01

    of bicyclists and risk situations. The findings should make a basis for preventive programmes in order to decrease the number and severity of bicyclists collision accidents. Data from the emergency room in a 2 year period was combined with data from questionnaires. The study group consisted of 1021 bicyclists...... group of accidents were the collisions with the 'soft' road users (bicyclists, mopeds, and pedestrians) and another group were the collisions with the 'hard' road users (motor vehicles, motorcycles). Preventive measures have to be directed at both these groups of accidents. To decrease the number...... of collision accidents with motor vehicles it is necessary to separate the bicyclists from the 'hard road traffic' especially at crossings. Preventive measures must also be directed at the bicyclists. Information must be given to warn the bicyclists against the risks, not only for collisions with motor...

  13. Replacement collision sequence studies in iron

    CERN Document Server

    Hou, M; Becquart, C S

    2002-01-01

    The properties of replacement collision sequences (RCS) in iron and their contribution to radiation damage are studied as they are generated in atomic collision cascades with the binary collision approximation Marlowe. Length distributions of RCS in collision cascades generated by primaries with a couple of ten keV kinetic energies are predicted short. Whatever the interatomic potential employed, at least 90% of the generated RCS have a length of no more than three successive collisions, whatever the directions. This property was found for all the known phases of iron at standard pressure (bcc and fcc). The RCS length distributions are not significantly influenced by the temperature nor by the accurate form of the model describing the energy loss in RCS. Close to 50% of the stable Frenkel pairs (FP) created result from RCS that are shorter than the vacancy-interstitial recombination distance estimated on the basis of molecular dynamics calculations. The other half results from longer RCS (about five successiv...

  14. Basins in ARC-continental collisions

    Science.gov (United States)

    Draut, Amy E.; Clift, Peter D.; Busby, Cathy; Azor, Antonio

    2012-01-01

    Arc-continent collisions occur commonly in the plate-tectonic cycle and result in rapidly formed and rapidly collapsing orogens, often spanning just 5-15 My. Growth of continental masses through arc-continent collision is widely thought to be a major process governing the structural and geochemical evolution of the continental crust over geologic time. Collisions of intra-oceanic arcs with passive continental margins (a situation in which the arc, on the upper plate, faces the continent) involve a substantially different geometry than collisions of intra-oceanic arcs with active continental margins (a situation requiring more than one convergence zone and in which the arc, on the lower plate, backs into the continent), with variable preservation potential for basins in each case. Substantial differences also occur between trench and forearc evolution in tectonically erosive versus tectonically accreting margins, both before and after collision. We examine the evolution of trenches, trench-slope basins, forearc basins, intra-arc basins, and backarc basins during arc-continent collision. The preservation potential of trench-slope basins is low; in collision they are rapidly uplifted and eroded, and at erosive margins they are progressively destroyed by subduction erosion. Post-collisional preservation of trench sediment and trench-slope basins is biased toward margins that were tectonically accreting for a substantial length of time before collision. Forearc basins in erosive margins are usually floored by strong lithosphere and may survive collision with a passive margin, sometimes continuing sedimentation throughout collision and orogeny. The low flexural rigidity of intra-arc basins makes them deep and, if preserved, potentially long records of arc and collisional tectonism. Backarc basins, in contrast, are typically subducted and their sediment either lost or preserved only as fragments in melange sequences. A substantial proportion of the sediment derived from

  15. A method of inferring collision ratio based on maneuverability of own ship under critical collision conditions

    Science.gov (United States)

    You, Youngjun; Rhee, Key-Pyo; Ahn, Kyoungsoo

    2013-06-01

    In constructing a collision avoidance system, it is important to determine the time for starting collision avoidance maneuver. Many researchers have attempted to formulate various indices by applying a range of techniques. Among these indices, collision risk obtained by combining Distance to the Closest Point of Approach (DCPA) and Time to the Closest Point of Approach (TCPA) information with fuzzy theory is mostly used. However, the collision risk has a limit, in that membership functions of DCPA and TCPA are empirically determined. In addition, the collision risk is not able to consider several critical collision conditions where the target ship fails to take appropriate actions. It is therefore necessary to design a new concept based on logical approaches. In this paper, a collision ratio is proposed, which is the expected ratio of unavoidable paths to total paths under suitably characterized operation conditions. Total paths are determined by considering categories such as action space and methodology of avoidance. The International Regulations for Preventing Collisions at Sea (1972) and collision avoidance rules (2001) are considered to solve the slower ship's dilemma. Different methods which are based on a constant speed model and simulated speed model are used to calculate the relative positions between own ship and target ship. In the simulated speed model, fuzzy control is applied to determination of command rudder angle. At various encounter situations, the time histories of the collision ratio based on the simulated speed model are compared with those based on the constant speed model.

  16. Oceanic microplate formation records the onset of India-Eurasia collision

    Science.gov (United States)

    Matthews, Kara J.; Dietmar Müller, R.; Sandwell, David T.

    2016-01-01

    Mapping of seafloor tectonic fabric in the Indian Ocean, using high-resolution satellite-derived vertical gravity gradient data, reveals an extinct Pacific-style oceanic microplate ('Mammerickx Microplate') west of the Ninetyeast Ridge. It is one of the first Pacific-style microplates to be mapped outside the Pacific basin, suggesting that geophysical conditions during formation probably resembled those that have dominated at eastern Pacific ridges. The microplate formed at the Indian-Antarctic ridge and is bordered by an extinct ridge in the north and pseudofault in the south, whose conjugate is located north of the Kerguelen Plateau. Independent microplate rotation is indicated by asymmetric pseudofaults and rotated abyssal hill fabric, also seen in multibeam data. Magnetic anomaly picks and age estimates calculated from published spreading rates suggest formation during chron 21o (∼47.3 Ma). Plate reorganizations can trigger ridge propagation and microplate development, and we propose that Mammerickx Microplate formation is linked with the India-Eurasia collision (initial 'soft' collision). The collision altered the stress regime at the Indian-Antarctic ridge, leading to a change in segmentation and ridge propagation from an establishing transform. Fast Indian-Antarctic spreading that preceded microplate formation, and Kerguelen Plume activity, may have facilitated ridge propagation via the production of thin and weak lithosphere; however both factors had been present for tens of millions of years and are therefore unlikely to have triggered the event. Prior to the collision, the combination of fast spreading and plume activity was responsible for the production of a wide region of undulate seafloor to the north of the extinct ridge and 'W' shaped lineations that record back and forth ridge propagation. Microplate formation provides a precise means of dating the onset of the India-Eurasia collision, and is completely independent of and complementary to timing

  17. Active Tectonics and Erosional Unloading at the Eastern Margin of the Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    Alexander L. Densmore; LI Yong; Michael A. Ellis; ZHOU Rongjun

    2005-01-01

    The eastern margin of the Tibetan Plateau is marked by an extremely steep mountain front with relief of over 5 km. This topography, coupled with abundant Mesozoic thrusts within the margin, explains why tectonic maps of the India-Asia collision typically show the eastern margin as a major thrust zone. Actually, it does not like that. Field observations suggest that the margin is better characterized as a zone of NNE-directed dextral shear with extensive strike-slip faulting and secondary thrusting. The high relief and steep gradients are partially explained by erosional unloading of an elastic lithosphere; the pre-erosion inherited topography may be the inherited Mesozoic thrust belt landscape modified by a component of Cenozoic tectonic shortening.

  18. Structural pattern of eastern Himalayan syntaxis in Namjagbarwa and its formation process

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Jinjiang; JI; Jianqing; ZHONG; Dalai; DING; Lin; HE

    2004-01-01

    The structural pattern of the eastern Himalayan syntaxis in Namjagbarwa consists of two series of structures with different styles. One series compiles the earlier ductile contractional and lateral-slip deformation system, formed by nearly north-south shortening within the syntaxis, left-lateral and right-lateral slipping along its western and eastern boundaries respectively. They were possibly produced by the indentation of the Indian continent into Asian continent after India-Asia collision. The peak deformation-metamorphic ages in these structures are 62-60 Ma, ~23 Ma and ~13 Ma. The other series is composed of ductile-brittle normal faults distributing concentrically and dipping toward the outsides of Namjagbarwa Peak. They were probably the collapse structures caused by rapid uplift in a later time and the beginning ages for the normal faulting are about 7.3-6.3 Ma.

  19. Photon scattering in muon collisions.

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, M.

    1997-12-18

    The authors estimate the benefit of muon colliders for photon physics. They calculate the rate at which photons are emitted from muon beams in different production mechanisms. Bremsstrahlung is reduced, beamstrahlung disappears, and laser backscattering suffers from a bad conversion of the incoming to the outgoing photon beam in addition to requiring very short wavelengths. As a consequence, the cross sections for jet photoproduction in {mu}p and {mu}{sup +} {mu}{sup {minus}} collisions are reduced by factors of 2.2 and 5 compared to ep and e{sup +} e{sup {minus}} machines. However, the cross sections remain sizable and measurable giving access to the photon and proton parton densities down to x values of 10{sup {minus}3} to 10{sup {minus}4}.

  20. Relativistic heavy-ion collisions

    CERN Document Server

    Bhalerao, Rajeev S

    2014-01-01

    The field of relativistic heavy-ion collisions is introduced to the high-energy physics students with no prior knowledge in this area. The emphasis is on the two most important observables, namely the azimuthal collective flow and jet quenching, and on the role fluid dynamics plays in the interpretation of the data. Other important observables described briefly are constituent quark number scaling, ratios of particle abundances, strangeness enhancement, and sequential melting of heavy quarkonia. Comparison is made of some of the basic heavy-ion results obtained at LHC with those obtained at RHIC. Initial findings at LHC which seem to be in apparent conflict with the accumulated RHIC data are highlighted.

  1. CHARACTERIZATION OF WILD PIG VEHICLE COLLISIONS

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, J; Paul E. Johns, P

    2007-05-23

    Wild pig (Sus scrofa) collisions with vehicles are known to occur in the United States, but only minimal information describing these accidents has been reported. In an effort to better characterize these accidents, data were collected from 179 wild pig-vehicle collisions from a location in west central South Carolina. Data included accident parameters pertaining to the animals involved, time, location, and human impacts. The age structure of the animals involved was significantly older than that found in the population. Most collisions involved single animals; however, up to seven animals were involved in individual accidents. As the number of animals per collision increased, the age and body mass of the individuals involved decreased. The percentage of males was significantly higher in the single-animal accidents. Annual attrition due to vehicle collisions averaged 0.8 percent of the population. Wild pig-vehicle collisions occurred year-round and throughout the 24-hour daily time period. Most accidents were at night. The presence of lateral barriers was significantly more frequent at the collision locations. Human injuries were infrequent but potentially serious. The mean vehicle damage estimate was $1,173.

  2. Jet Production in p-Pb Collisions

    CERN Document Server

    Connors, Megan

    2014-01-01

    One of the major results from the study of high energy heavy ion collisions is the observation of jet quenching. The suppression of the number of jets observed in heavy ion collisions relative to pp collisions at the same energy scaled by the number of binary collisions, is attributed to partonic energy loss in the quark gluon plasma (QGP). However, cold nuclear matter effects due to the presence of a nucleus in the initial state could also influence this measurement. To disentangle these effects p-Pb collisions are studied, where QGP formation is not expected to occur and only cold nuclear matter effects are present. In addition to being an important baseline for understanding jet quenching, jets in p-Pb collisions may also be used to provide constraints on the nuclear parton distribution functions. Fully reconstructed jets measured using the ALICE tracking system and electro-magnetic calorimeter in p-Pb collisions at $\\sqrt{s_{NN}}=5.02$ TeV are reported. In addition to the spectra, studies of the jet fragm...

  3. Study on Collision Characters for SPAR Platform

    Institute of Scientific and Technical Information of China (English)

    HU Zhi-qiang; CUI Wei-cheng

    2008-01-01

    This paper presents the research on the external mechanism of collision characters for a SPAR platform. The collision characters of SPAR platform have not attracted so much attention as that of ships in the past, because short of this kind of collision accidents reported. But with the increasing number of SPAR platforms in the world, the possibility of such kind of accident also increases. Therefore, it is necessary to master the character of SPAR collision. Model test technique is employed to study the external mechanism. The collision scenario is a ship colliding with a SPAR platform moored in the site with 1500 meters water depth. The striking ship hits the SPAR platform on the hard tank near water surface in its longitudinal direction. The specifics of the SPAR's motions and the tension forces of the mooring lines are collected to summarize the hydrodynamic characters in the collision scenario. It is found that the maximal displacements and the maximal pitch angles of the SPAR platform, and the maximal tension forces of mooring lines are all linearly proportional to the initial velocity of the striking ship basically. Mooring lines play elastic roles in the collision course.

  4. Strategy Formation in Eastern Jutland

    DEFF Research Database (Denmark)

    Olesen, Kristian

    2008-01-01

    in the area.   The municipalities acknowledge the articulation of the city region and the initiated planning process.  However, the municipalities might see the arena as means to lobby for infrastructure investments in Eastern Jutland, as it is doubtful whether the municipalities will feel encouraged to enter...... a process, which is aiming at increasing the national regulation within their territory.    The result might very well be that the discussion about future infrastructure investments is not linked to discussions about future urban development in Eastern Jutland.  These aspects raises serious questions about...... on which level a serious strategy formation process can take place.  There is a danger that a common strategic spatial plan is more an expression of the lowest common denominator and the municipalities request for infrastructure investments rather than being a spatial strategy with transformative power. ...

  5. Transition from the Farallon Plate subduction to the collision between South and Central America: Geological evolution of the Panama Isthmus

    Science.gov (United States)

    Barat, Flore; Mercier de Lépinay, Bernard; Sosson, Marc; Müller, Carla; Baumgartner, Peter O.; Baumgartner-Mora, Claudia

    2014-05-01

    This paper presents new geological constraints on the collision of southern Central America with South America, and the resulting deformational episodes that have affected the Panama Isthmus since the Late Cretaceous. The Panama Isthmus is located in southwestern Central America, and it represents the zone of contact between the two land masses: Central America and South America. This collision event is still active today. It has resulted in regional uplift since the Late Miocene/Pliocene and is responsible for the Great American Biotic Interchange between South and North America. Depending on the methods of investigation used, and due to the lack of data available, the time when this collision began is still widely debated and poorly constrained. To better constrain this age, we have studied the rock formations and the tectonic deformations in central and eastern Panama that have occurred since the Late Cretaceous. This study presents new rock ages, field-work documentation and analyses, and seismic-line interpretations, and it is complemented by spatial images for the eastern Panama area. During the Middle Eocene, a number of changes suddenly appeared in the geological records that were synchronous with the break-up of southern Central America into two smaller blocks: Chorotega and Chocó. Our main results identify the prevalence of an extensional tectonic regime from the Middle Eocene to the Middle Miocene that caused the formation of horst and graben structures with thick sedimentary basin fills, and a synchronous clockwise block rotation. Here, we propose that these geologic events are associated with the initiation of the oblique collision of southern Central America with South America. The first contact of the southeastern extremity of Central America occurred around 40 Ma to 38 Ma, and then propagated northwestwards. We describe here this long-term collision episode in relation to the history of the Panama Isthmus.

  6. Wireless vehicular networks for car collision avoidance

    CERN Document Server

    2013-01-01

    Wireless Vehicular Networks for Car Collision Avoidance focuses on the development of the ITS (Intelligent Transportation Systems) in order to minimize vehicular accidents. The book presents and analyses a range of concrete accident scenarios while examining the causes of vehicular collision and proposing countermeasures based on wireless vehicular networks. The book also describes the vehicular network standards and quality of service mechanisms focusing on improving critical dissemination of safety information. With recommendations on techniques and protocols to consider when improving road safety policies in order to minimize crashes and collision risks.

  7. Holographic heavy ion collisions with baryon charge

    CERN Document Server

    Casalderrey-Solana, Jorge; van der Schee, Wilke; Triana, Miquel

    2016-01-01

    We numerically simulate collisions of charged shockwaves in Einstein-Maxwell theory in anti-de Sitter space as a toy model of heavy ion collisions with non-zero baryon charge. The stress tensor and the baryon current become well described by charged hydrodynamics at roughly the same time. The effect of the charge density on generic observables is typically no larger than 15\\%. %The rapidity profile of the charge is wider than the profile of the local energy density. We find significant stopping of the baryon charge and compare our results with those in heavy ion collision experiments.

  8. Mid-air collisions enhance saltation

    CERN Document Server

    Carneiro, M V; Pähtz, T; Herrmann, H J

    2013-01-01

    Here we address the old question in Aeolian particle transport about the importance of mid-air collisions. We find that surprisingly these collisions do enhance the overall flux substantially. The effect depends strongly on restitution coefficient and wind speed. We can explain this observation as a consequence of a "soft bed" of grains which floats above the surface and reflects the highest flying particles. We make the unexpected observation that the flux is maximized for an intermediate restitution coefficient of about 0.65, which is comparable to the values experimentally measured for collisions between sand grains.

  9. Cold heteronuclear atom-ion collisions

    CERN Document Server

    Zipkes, Christoph; Ratschbacher, Lothar; Sias, Carlo; Köhl, Michael

    2010-01-01

    We study cold heteronuclear atom ion collisions by immersing a trapped single ion into an ultracold atomic cloud. Using ultracold atoms as reaction targets, our measurement is sensitive to elastic collisions with extremely small energy transfer. The observed energy-dependent elastic atom-ion scattering rate deviates significantly from the prediction of Langevin but is in full agreement with the quantum mechanical cross section. Additionally, we characterize inelastic collisions leading to chemical reactions at the single particle level and measure the energy-dependent reaction rate constants. The reaction products are identified by in-trap mass spectrometry, revealing the branching ratio between radiative and non-radiative charge exchange processes.

  10. Vorticity in Heavy-Ion Collisions

    CERN Document Server

    Deng, Wei-Tian

    2016-01-01

    We study the event-by-event generation of flow vorticity in RHIC Au + Au collisions and LHC Pb + Pb collisions by using the HIJING model. Different definitions of the vorticity field and velocity field are considered. A variety of properties of the vorticity are explored, including the impact parameter dependence, the collision energy dependence, the spatial distribution, the event-by-event fluctuation of the magnitude and azimuthal direction, and the time evolution. In addition, the spatial distribution of the flow helicity is also studied.

  11. Vorticity in heavy-ion collisions

    Science.gov (United States)

    Deng, Wei-Tian; Huang, Xu-Guang

    2016-06-01

    We study the event-by-event generation of flow vorticity in the BNL Relativistic Heavy Ion Collider Au +Au collisions and CERN Large Hadron Collider Pb +Pb collisions by using the hijing model. Different definitions of the vorticity field and velocity field are considered. A variety of properties of the vorticity are explored, including the impact parameter dependence, the collision energy dependence, the spatial distribution, the event-by-event fluctuation of the magnitude and azimuthal direction, and the time evolution. In addition, the spatial distribution of the flow helicity is also studied.

  12. Relativistic collisions of structured atomic particles

    Energy Technology Data Exchange (ETDEWEB)

    Voitkiv, A.; Ullrich, J. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

    2008-07-01

    The book reviews the progress achieved over the last decade in the study of collisions between an ion and an atom in which both the atomic particles carry electrons and can undergo transitions between their internal states - including continua. It presents the detailed considerations of different theoretical approaches, that can be used to describe collisions of structured atomic particles for the very broad interval of impact energies ranging from 0.5-1 MeV/u till extreme relativistic energies where the collision velocity very closely approaches the speed of light. (orig.)

  13. Collision geometry and particle production in high energy heavy ion collision experiments

    Institute of Scientific and Technical Information of China (English)

    WANG Ya-Ping; ZHOU Dai-Mei; HUANG Rui-Dian; CAI Xu

    2008-01-01

    An overview of research status of soft physics in high energy heavy-ion collision experiments and recent experimental results are presented.This paper includes four parts:1)Theoretical predictions of quarkgluon plasma and introduction for high energy heavy ion collision experiments.2)Experimental status on collision geometry.3)Experimental status on particle production.4)Conclusion and outlook for research status of soft physics in LHC/ALICE.

  14. Some soft aspects of relativistic ion collisions

    CERN Document Server

    Boimska, Bozena

    2009-01-01

    Concepts of wounded nucleon and quark participants have been used for years to parametrize and/or to explain many features of high energy nuclear collisions. Some results illustrating successes and failures of these two approaches are presented, including the latest developments. In particular, results on identified particle production from nuclear collisions measured by the NA49 experiment at the CERN-SPS are shown. The study has been done for both the nucleon and the constituent quark frameworks using the nuclear overlap model. In addition, some preliminary observations concerning the behavior of pT spectra at forward rapidities, expressed in terms of the nuclear modification factor, for hadron-nucleus collisions at the SPS energy are also presented. These results are in relevance to RHIC results for deuteron-gold collisions often interpreted as a manifestation of saturation and/or color glass condensate.

  15. Recent results on relativistic heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Munhoz, Marcelo [Universidade de Sao Paulo (IF/USP), Sao Paulo, SP (Brazil). Inst. de Fisica

    2013-07-01

    Full text: The study of relativistic heavy ion collisions is a very important tool in order to understand the strong interaction described by QCD. The formation of the Quark-Gluon Plasma and the study of its properties is a very challenging quest. The Large Hadron Collider (LHC) from CERN (European Organization for Nuclear Research) generates ultra-relativistic Pb + Pb collisions at the TeV scale inaugurating a new era for such studies. Three experiments, ATLAS, CMS and ALICE are able to measure the products of such collisions. In special, the ALICE experiment was designed specifically for the study of heavy ion collisions. In this presentation, I'll discuss the latest results that shed light in the QGP understanding. (author)

  16. GRACAT, Software for grounding and collision analysis

    DEFF Research Database (Denmark)

    Friis-Hansen, Peter; Simonsen, Bo Cerup

    2002-01-01

    From 1998 to 2001 an integrated software package for grounding and collision analysis was developed at the Technical University of Denmark within the ISESO project at the cost of six man years (0.75M US$). The software provides a toolbox for a multitude of analyses related to collision and ground......From 1998 to 2001 an integrated software package for grounding and collision analysis was developed at the Technical University of Denmark within the ISESO project at the cost of six man years (0.75M US$). The software provides a toolbox for a multitude of analyses related to collision...... route where the result is the probability density functions for the cost of oil outflow in a given area per year for the two vessels. In this paper we describe the basic modelling principles and the capabilities of the software package. The software package can be downloaded for research purposes from...

  17. System size in relativistic heavy ion collisions

    Institute of Scientific and Technical Information of China (English)

    WANG Yang-Yang; ZHAO Lin-Jie; YUAN Zhong-Sheng; ZHANG Dan-Dan; FANG Wei; XU Ming-Mei

    2011-01-01

    System size is more than a geometrical quantity in relativistic heavy ion collisions; it is closely related to evolution process,i.e.a different system size corresponds to a different evolution process,and whether QGP is produced depends on the system size.We propose that the system size should be under the same level when comparing the measurements from different colliding nuclei.The equivalence of the peripheral collisions of Au-Au and the central collisions of smaller nuclei is studied using the Monte Carlo method.Comparing the transverse overlapping area of the colliding nuclei,the number of participant nucleons and the number of nucleon-nucleon binary collisions in various colliding nuclei,we give an estimate of the correspondence in system size.This is helpful in the experimental comparison of the measurements from different colliding nuclei.

  18. Theory overview of Heavy Ion collisions

    CERN Document Server

    Lappi, T

    2016-01-01

    This presentation discusses some recently active topics in the theoretical interpretation of high energy heavy ion collisions at the LHC and at RHIC. We argue that the standard paradigm for understanding the spacetime evolution of the bulk of the matter produced in the collision is provided by viscous relativistic hydrodynamics, which can be used to systematically extract properties of the QCD medium from experimental results. The initial conditions of this hydrodynamical evolution are increasingly well understood in terms of gluon saturation, and can be quantified using Classical Yang-Mills fields and QCD effective kinetic theory. Hard and electromagnetic probes of the plasma provide additional constraints. A particularly fascinating subject are high multiplicity proton-proton and proton-nucleus collisions, where some of the characteristics previously attributed to only nucleus-nucleus collisions have been observed.

  19. LHC: Collisions on course for 2007

    CERN Multimedia

    2006-01-01

    In the LHC tunnel and caverns, a particle accelerator and detectors are rapidly taking shape. At last week's Council meeting, delegates took stock of the year's progress towards first collisions in 2007.

  20. Particle Interferometry in Heavy-Ion Collisions

    CERN Document Server

    Heinz, Ulrich W

    1997-01-01

    By measuring hadronic single-particle spectra and two-particle correlations in heavy-ion collisions, the size and dynamical state of the collision fireball at freeze-out can be reconstructed. I discuss the relevant theoretical methods and their limitations. By applying the formalism to recent pion correlation data from Pb+Pb collisions at CERN we demonstrate that the collision zone has undergone strong transverse growth before freeze-out (by a factor 2-3 in each direction), and that it expands both longitudinally and transversally. From the thermal and flow energy density at freeze-out the energy density at the onset of transverse expansion can be estimated from conservation laws. It comfortably exceeds the critical value for the transition to color deconfined matter.

  1. Active Collision Avoidance for Planetary Landers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advancements in radar technology have resulted in commercial, automotive collision avoidance radars. These radar systems typically use 37GHz or 77GHz interferometry...

  2. Collision Avoidance of Trains Using Arm7

    Directory of Open Access Journals (Sweden)

    Dr. K. R. R. Mohan Rao

    2015-11-01

    Full Text Available Railways are the popular mode of Transport in almost all major cities of the World. Railways are the most widely used and comfortable modes of transportation system. The major cause for railway accidents is collision of trains on the same track. The main aim of this anti collision system is to identify collision points and to report these error cases to main control room nearer to the station as well as grid control station. Majority of accidents occurred due to improper communication among the network between drivers and control room, due to wrong signaling, worst atmospheric condition, immediate change of route. The train driver doesn’t get proper information in time leading to hazardous situations. So this system by using zigbee protocol provides communication in between trains, which provide information or track id of one train to another train to avoid collision.

  3. VT Vehicle-Animal Collisions - 2006

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) This data (ROADKILL06) describes the locations of vehicle-animal collisions. This shapefile is a collection of collsion information collected by...

  4. Novel energy sharing collisions of multicomponent solitons

    Indian Academy of Sciences (India)

    T Kanna; K Sakkaravarthi; M Vijayajayanthi

    2015-11-01

    In this paper, we discuss the fascinating energy sharing collisions of multicomponent solitons in certain incoherently coupled and coherently coupled nonlinear Schrödinger-type equations arising in the context of nonlinear optics.

  5. Looking for the Odderon in photon collisions

    CERN Document Server

    Pire, Bernard; Szymanowski, Lech; Wallon, Samuel

    2010-01-01

    We discuss the production of two pion pairs in photon collisions at high energies. We calculate the according matrix elements in k_T-factorization and discuss the possibility to reveal the existence of the perturbative Odderon by charge asymmetries.

  6. Are There Frame-Distortion Contributions to Collision-Induced Absorption and Collision-Induced Light Scattering?

    Science.gov (United States)

    Hohm, Uwe

    2007-12-01

    Collision-induced spectroscopy, such as collision-induced absorption (CIA) and collision-induced light scattering (CILS), can give valuable information on permanent electric moments, polarizabilities and intermolecular-interaction potentials. In general the collision-induced spectra of the pure rare-gases and their binary mixtures are understood fairly well. However if at least one of the collision partners is a molecule then in some cases the spectra show features which can hardly be explained by current theories which deal with the case of undistorted molecules. Here we discuss the possibility of collision-induced frame distortion as an additional effect to be considered in collision-induced spectroscopy.

  7. Nuclear collisions at the Future Circular Collider

    Science.gov (United States)

    Armesto, N.; Dainese, A.; d'Enterria, D.; Masciocchi, S.; Roland, C.; Salgado, C. A.; van Leeuwen, M.; Wiedemann, U. A.

    2016-12-01

    The Future Circular Collider is a new proposed collider at CERN with centre-of-mass energies around 100 TeV in the pp mode. Ongoing studies aim at assessing its physics potential and technical feasibility. Here we focus on updates in physics opportunities accessible in pA and AA collisions not covered in previous Quark Matter contributions, including Quark-Gluon Plasma and gluon saturation studies, novel hard probes of QCD matter, and photon-induced collisions.

  8. Nuclear collisions at the Future Circular Collider

    CERN Document Server

    Armesto, N; d'Enterria, D; Masciocchi, S; Roland, C; Salgado, C A; van Leeuwen, M; Wiedemann, U A

    2016-01-01

    The Future Circular Collider is a new proposed collider at CERN with centre-of-mass energies around 100 TeV in the pp mode. Ongoing studies aim at assessing its physics potential and technical feasibility. Here we focus on updates in physics opportunities accessible in pA and AA collisions not covered in previous Quark Matter contributions, including Quark-Gluon Plasma and gluon saturation studies, novel hard probes of QCD matter, and photon-induced collisions.

  9. Passive Collision Avoidance System for UAS

    Science.gov (United States)

    2008-09-01

    customization (Figure 1). From discussions with our customers , partners, and government technical officers, we have developed the following CA requirements...place when aircraft are not compliant such as the Tu-154 / DHL mid air collision and the AIR RAGE Airbus mid air collision. 4 The two (2) examples...configuration is 20 at the nose, 50 at the wing tips and >100 at the rear. They will be “plug and play” with the TP allowing easy customization

  10. COLLISIONS OF ROAD VEHICLES WITH BRIDGE COLUMNS

    OpenAIRE

    2015-01-01

    As speed limits and traffic on city roads continue to increase, collisions between road vehicles and bridge columns are becoming more common. Current regulations analyze collision with one major simplification: replacing dynamic action with the equivalent static force. In the present paper, we develop a numerical model of a typical Croatian overpass and loaded it with an equivalent static load according to the EN1991-7 and ASSHTO LRFD provisions, analyzing the differences in overpass behavior...

  11. ALICE: Simulated lead-lead collision

    CERN Multimedia

    2003-01-01

    This track is an example of simulated data modelled for the ALICE detector on the Large Hadron Collider (LHC) at CERN, which will begin taking data in 2008. ALICE will focus on the study of collisions between nuclei of lead, a heavy element that produces many different particles when collided. It is hoped that these collisions will produce a new state of matter known as the quark-gluon plasma, which existed billionths of a second after the Big Bang.

  12. Global Λ hyperon polarization in nuclear collisions

    Science.gov (United States)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Bunzarov, I.; Butterworth, J.; Caines, H.; de La Barca Sánchez, M. Calderón; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, X.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; de Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Federicova, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harlenderova, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, T.; Huang, B.; Huang, X.; Huang, H. Z.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Kocmanek, M.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulathunga, N.; Kumar, L.; Kvapil, J.; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, W.; Li, Y.; Lidrych, J.; Lin, T.; Lisa, M. A.; Liu, H.; Liu, P.; Liu, Y.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, S.; Luo, X.; Ma, G. L.; Ma, L.; Ma, Y. G.; Ma, R.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mizuno, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Saur, M.; Schambach, J.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seger, J.; Sergeeva, M.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, A.; Sharma, M. K.; Shen, W. Q.; Shi, Z.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Strikhanov, M.; Stringfellow, B.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, X. M.; Sun, X.; Surrow, B.; Svirida, D. N.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; van Buren, G.; van Nieuwenhuizen, G.; Vasiliev, A. N.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y. F.; Xu, Z.; Yang, Y.; Yang, Q.; Yang, C.; Yang, S.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Z.; Zhang, X. P.; Zhang, J. B.; Zhang, S.; Zhang, J.; Zhang, Y.; Zhang, J.; Zhang, S.; Zhao, J.; Zhong, C.; Zhou, L.; Zhou, C.; Zhu, X.; Zhu, Z.; Zyzak, M.

    2017-08-01

    The extreme energy densities generated by ultra-relativistic collisions between heavy atomic nuclei produce a state of matter that behaves surprisingly like a fluid, with exceptionally high temperature and low viscosity. Non-central collisions have angular momenta of the order of 1,000ћ, and the resulting fluid may have a strong vortical structure that must be understood to describe the fluid properly. The vortical structure is also of particular interest because the restoration of fundamental symmetries of quantum chromodynamics is expected to produce novel physical effects in the presence of strong vorticity. However, no experimental indications of fluid vorticity in heavy ion collisions have yet been found. Since vorticity represents a local rotational structure of the fluid, spin-orbit coupling can lead to preferential orientation of particle spins along the direction of rotation. Here we present measurements of an alignment between the global angular momentum of a non-central collision and the spin of emitted particles (in this case the collision occurs between gold nuclei and produces Λ baryons), revealing that the fluid produced in heavy ion collisions is the most vortical system so far observed. (At high energies, this fluid is a quark-gluon plasma.) We find that Λ and hyperons show a positive polarization of the order of a few per cent, consistent with some hydrodynamic predictions. (A hyperon is a particle composed of three quarks, at least one of which is a strange quark; the remainder are up and down quarks, found in protons and neutrons.) A previous measurement that reported a null result, that is, zero polarization, at higher collision energies is seen to be consistent with the trend of our observations, though with larger statistical uncertainties. These data provide experimental access to the vortical structure of the nearly ideal liquid created in a heavy ion collision and should prove valuable in the development of hydrodynamic models that

  13. Central collisions-The general case

    Science.gov (United States)

    Lyublinskaya, Irina E.

    1998-01-01

    The central elastic and inelastic collisions have been analyzed in general vector form. The proposed analysis results in equations, which have simple physical interpretation and can be easily applied to different special cases. The mathematical basis needed for the analysis includes only vector addition and dot-product of vectors. It allows teachers to introduce proposed approach to collisions already in trigonometry-based physic courses.

  14. Kink Collisions in Curved Field Space

    Science.gov (United States)

    Ahlqvist, Pontus; Eckerle, Kate; Greene, Brian

    2015-04-01

    We study bubble universe collisions in the ultrarelativistic limit with the new feature of allowing for nontrivial curvature in field space. We establish a simple geometrical interpretation of such collisions in terms of a double family of field profiles whose tangent vector fields stand in mutual parallel transport. This provides a generalization of the well-known flat field space limit of the free passage approximation. We investigate the limits of this approximation and illustrate our analytical results with numerical simulations.

  15. Nuclear collisions at the Future Circular Collider

    Energy Technology Data Exchange (ETDEWEB)

    Armesto, N., E-mail: nestor.armesto@usc.es [Departamento de Física de Partículas and IGFAE, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Galicia-Spain (Spain); Dainese, A. [INFN – Sezione di Padova, 35131 Padova (Italy); D' Enterria, D. [Physics Department, CERN, CH-1211 Genéve 23 (Switzerland); Masciocchi, S. [EMMI and GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Roland, C. [Massachusetts Institute of Technology, Cambridge, MA 02139-4307 (United States); Salgado, C.A. [Departamento de Física de Partículas and IGFAE, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Galicia-Spain (Spain); Leeuwen, M. van [Nikhef, National Institute for Subatomic Physics, Amsterdam (Netherlands); Institute for Subatomic Physics of Utrecht University, Utrecht (Netherlands); Wiedemann, U.A. [Physics Department, CERN, CH-1211 Genéve 23 (Switzerland)

    2016-12-15

    The Future Circular Collider is a new proposed collider at CERN with centre-of-mass energies around 100 TeV in the pp mode. Ongoing studies aim at assessing its physics potential and technical feasibility. Here we focus on updates in physics opportunities accessible in pA and AA collisions not covered in previous Quark Matter contributions, including Quark-Gluon Plasma and gluon saturation studies, novel hard probes of QCD matter, and photon-induced collisions.

  16. The effect of collisions in ionogram inversion

    CERN Document Server

    Scotto, Carlo

    2012-01-01

    The results of this paper demonstrate how the effect of collisions on the group refraction index is small, when the ordinary ray is considered. If, however, in order to improve the performance of a system for automatic interpretation of ionograms, the information contained in ordinary and extraordinary traces is combined, the effect of collisions between the electrons and neutral molecules should be taken into account for the extraordinary ray.

  17. Coulomb collision effects on linear Landau damping

    Energy Technology Data Exchange (ETDEWEB)

    Callen, J. D., E-mail: callen@engr.wisc.edu [University of Wisconsin, Madison, Wisconsin 53706-1609 (United States)

    2014-05-15

    Coulomb collisions at rate ν produce slightly probabilistic rather than fully deterministic charged particle trajectories in weakly collisional plasmas. Their diffusive velocity scattering effects on the response to a wave yield an effective collision rate ν{sub eff} ≫ ν and a narrow dissipative boundary layer for particles with velocities near the wave phase velocity. These dissipative effects produce temporal irreversibility for times t ≳ 1/ν{sub eff} during Landau damping of a small amplitude Langmuir wave.

  18. Molecular vibrational states during a collision

    Science.gov (United States)

    Recamier, Jose A.; Jauregui, Rocio

    1995-01-01

    Alternative algebraic techniques to approximate a given Hamiltonian by a harmonic oscillator are described both for time-independent and time-dependent systems. We apply them to the description of a one dimensional atom-diatom collision. From the resulting evolution operator, we evaluate vibrational transition probabilities as well as other time-dependent properties. As expected, the ground vibrational state becomes a squeezed state during the collision.

  19. The Underlying Physics in Wetted Particle Collisions

    Science.gov (United States)

    Donahue, Carly; Hrenya, Christine; Davis, Robert

    2008-11-01

    Wetted granular particles are relevant in many industries including the pharmaceutical and chemical industries and has applications to granulation, filtration, coagulation, spray coating, drying and pneumatic transport. In our current focus, we investigate the dynamics of a three-body normal wetted particle collision. In order to conduct collisions we use an apparatus called a ``Stokes Cradle,'' similar to the Newton's Cradle (desktop toy) except that the target particles are covered with oil. Here, we are able to vary the oil thickness, oil viscosity, and material properties. With a three particle collision there are four possible outcomes: fully agglomerated (FA); Newton's Cradle (NC), the striker and the first target ball are agglomerated and the last target ball is separated; Reverse Newton's Cradle (RNC), the striker is separated and the two targets are agglomerated; and fully separated (FS). Varying the properties of the collisions, we have observed all four outcomes. We use elastohydrodynamics as a theoretical basis for modeling the system. We also have considered the glass transition of the oil as the pressure increases upon impact and the cavitation of the oil as the pressure drops below the vapor pressure upon rebound. A toy model has been developed where the collision is modeled as a series of two-body collisions. A qualitative agreement between the toy model and experiments gives insight into the underlying physics.

  20. Planetesimal Collisions as a Chondrule Forming Event

    Science.gov (United States)

    Wakita, Shigeru; Matsumoto, Yuji; Oshino, Shoichi; Hasegawa, Yasuhiro

    2017-01-01

    Chondritic meteorites contain unique spherical materials named chondrules: sub-mm sized silicate grains once melted in a high temperature condition in the solar nebula. We numerically explore one of the chondrule forming processes—planetesimal collisions. Previous studies have found that impact jetting via protoplanet–planetesimal collisions can make chondrules with 1% of the impactors’ mass, when the impact velocity exceeds 2.5 km s‑1. Based on the mineralogical data of chondrules, undifferentiated planetesimals would be more suitable for chondrule-forming collisions than potentially differentiated protoplanets. We examine planetesimal–planetesimal collisions using a shock physics code and find two things: one is that planetesimal–planetesimal collisions produce nearly the same amount of chondrules as protoplanet–planetesimal collisions (∼1%). The other is that the amount of produced chondrules becomes larger as the impact velocity increases when two planetesimals collide with each other. We also find that progenitors of chondrules can originate from deeper regions of large targets (planetesimals or protoplanets) than small impactors (planetesimals). The composition of targets is therefore important, to fully account for the mineralogical data of currently sampled chondrules.

  1. Region 1 Acoustic Bat Inventory: National Wildlife Refuges in Eastern Oregon, Eastern Washington, and Idaho

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Bat species were inventoried on National Wildlife Refuges in Eastern Oregon, Eastern Washington, and Idaho using acoustic methods. Samples were collected between...

  2. LHC Report: First collisions soon

    CERN Multimedia

    Jan Uythoven for the LHC team

    2012-01-01

    On the evening of Friday 16 March beams were accelerated in the LHC at 4 TeV for the first time: a new world record! According to the schedule for the machine restart it will take another three weeks before the stable beams mode – the requirement for the detectors to start taking data – is achieved.   During the beam commissioning period the equipment teams make sure that their systems – beam instrumentation, radio frequency, beam interlock, feedback on orbit and tune, etc. – are working flawlessly with beam. Confidence in the correct functioning of all the magnets, their settings and their alignment is obtained by detailed measurements of the optics and the physical aperture. The optics measurements include the beta* of the squeezed beam at the centre of the experiments where the collisions will soon take place. This year the aim is to have a smaller beta* of 60 cm for the ATLAS and CMS experiments. As a reminder, smaller values of beta* mean thinner and m...

  3. Strategy Formation in Eastern Jutland

    DEFF Research Database (Denmark)

    Olesen, Kristian

    2008-01-01

      In Eastern Jutland a strategy formation process has been initiated with the aim of developing a strategic spatial plan for the city region.  An organisation has been set up to deal with the first phase of the process, which is to carry out three functional analyses and prepare a common vision...... on which level a serious strategy formation process can take place.  There is a danger that a common strategic spatial plan is more an expression of the lowest common denominator and the municipalities request for infrastructure investments rather than being a spatial strategy with transformative power. ...

  4. Collision prediction software for radiotherapy treatments

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, Laura [Virginia Commonwealth University Medical Center, Richmond, Virginia 23298 (United States); Pearson, Erik A. [Techna Institute and the Princess Margaret Cancer Center, University Health Network, Toronto, Ontario M5G 2M9 (Canada); Pelizzari, Charles A., E-mail: c-pelizzari@uchicago.edu [Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois 60637 (United States)

    2015-11-15

    Purpose: This work presents a method of collision predictions for external beam radiotherapy using surface imaging. The present methodology focuses on collision prediction during treatment simulation to evaluate the clearance of a patient’s treatment position and allow for its modification if necessary. Methods: A Kinect camera (Microsoft, Redmond, WA) is used to scan the patient and immobilization devices in the treatment position at the simulator. The surface is reconstructed using the SKANECT software (Occipital, Inc., San Francisco, CA). The treatment isocenter is marked using simulated orthogonal lasers projected on the surface scan. The point cloud of this surface is then shifted to isocenter and converted from Cartesian to cylindrical coordinates. A slab models the treatment couch. A cylinder with a radius equal to the normal distance from isocenter to the collimator plate, and a height defined by the collimator diameter is used to estimate collisions. Points within the cylinder clear through a full gantry rotation with the treatment couch at 0° , while points outside of it collide. The angles of collision are reported. This methodology was experimentally verified using a mannequin positioned in an alpha cradle with both arms up. A planning CT scan of the mannequin was performed, two isocenters were marked in PINNACLE, and this information was exported to AlignRT (VisionRT, London, UK)—a surface imaging system for patient positioning. This was used to ensure accurate positioning of the mannequin in the treatment room, when available. Collision calculations were performed for the two treatment isocenters and the results compared to the collisions detected the room. The accuracy of the Kinect-Skanect surface was evaluated by comparing it to the external surface of the planning CT scan. Results: Experimental verification results showed that the predicted angles of collision matched those recorded in the room within 0.5°, in most cases (largest deviation

  5. CMS collision events: candidate Upsilons in heavy-ion collisions – Dec 2010

    CERN Multimedia

    McCauley, Thomas

    2011-01-01

    Candidate Upsilon decay to two muons observed in a lead-lead collision at the LHC. The two red lines (tracks) are the two muons, the mass of orange lines are tracks from other particles produced in the collision, whose energy is measured in the electromagnetic calorimeter (red cuboids) and the hadron calorimeter (blue cuboids).

  6. Evolution of stellar collision products in open clusters : II. A grid of low-mass collisions

    NARCIS (Netherlands)

    Glebbeek, E.; Pols, O.R.

    2008-01-01

    In a companion paper we studied the detailed evolution of stellar collision products that occurred in an N-body simulation of the old open cluster M 67 and compared our detailed models to simple prescriptions. In this paper we extend this work by studying the evolution of the collision products in o

  7. GPU Accelerated Real-Time Collision Handling in Virtual Disassembly

    Institute of Scientific and Technical Information of China (English)

    Peng Du; Jie-Yi Zhao; Wan-Bin Pan; Yi-Gang Wang

    2015-01-01

    Previous collision detection methods for virtual disassembly mainly detect collisions at discrete time intervals, and use oriented bounding boxes to speed up the process. However, these discrete methods cannot guarantee no penetration occurs when the components move. Meanwhile, because some of the components are embedded into each other, these components cannot be separated in the subsequent process. To solve these problems, we propose an approach for real-time collision handling by utilizing the computational power of modern GPUs. First we present a novel GPU-based collision handling framework for virtual disassembly. Second we use a collision-streams based continuous collision detection to guarantee no collision missed. Finally we introduce a triangle intersection detection algorithm to solve the problem that collision cannot be detected when the components are embedded into each other at the initial configuration. The experimental results show that our method can improve the overall performance of collision detection and achieve real-time simulation.

  8. Snakebite ethnopharmacopoeia of eastern Nicaragua.

    Science.gov (United States)

    Coe, Felix G; Anderson, Gregory J

    2005-01-04

    Results of an ethnopharmacognostic study of snakebite treatments in eastern Nicaragua are presented. Data and specimens were collected during several years of field studies. Field work consisted of plant collecting trips and interviews of snakedoctors. The annual mortality from snakebites in eastern Nicaragua is about 25% and most bites are caused by the fer-de-lance (Bothrops asper). The vascular flora of the region is estimated at 2500 species of which 435 have medicinal application including 81 that are used in snakebite treatment. The majority of species used in snakebite cures are flowering plants, 76% dicots and 20% monocots, and 80% are obtained from the second-growth forest. About half the species are herbs. Leaves are the most frequently utilized plant part. Most herbal remedies are prepared as decoctions and are administered orally. Remedies are mostly prepared with native wild species, but some are introduced domesticates, derived from either the American or Old World Tropics. All the species used contain at least one bioactive compound, and most of these bioactives have been shown in other studies to have pharmacological effects. The use of species in snakebite treatments does not necessarily imply efficacy, but it does give a limited list of species that can be studied pharmacologically for possible bioactive effects. Studies like this one are also important because they document traditional practices and species utilized for the people of the region studied as well.

  9. Mutual recombination in slow Si+ + H- collisions

    Institute of Scientific and Technical Information of China (English)

    Wang Jian-Guo; Liu Chun-Lei; Janev R. K.; Yan Jun; Shi Jian-Rong

    2006-01-01

    This paper studies the process of mutual neutralization of Si+ and H- ions in slow collisions within the multichannel Landau-Zener model. All important ionic-covalent couplings in this collision system are included in the collision dynamics. The cross sections for population of specific final states of product Si atom are calculated in the CM energy range 0.05 eV/u-5 keV/u. Both singlet and triplet states are considered. At collision energies below ~10 eV/u, the most populated singlet state is Si(3p4p, 1S0), while for energies above ~150eV/u it is the Si(3p, 4p, 1P1) state. In the case of triplet states, the mixed 3p4p(3 S1 +3P0) states are the most populated in the entire collision energy range investigated. The total cross section exhibits a broad maximum around 200-300 eV/u and for ECM ≤ 10eV/u it monotonically increases with decreasing the collision energy, reaching a value of 8 × 10-13 cm2 at ECM = 0.05 eV/u. The ion-pair formation process in Si(3p2 3PJ)+H(1s) collisions has also been considered and its cross section in the considered energy range is very small (smaller than 10-20 cm2 in the energy region below 1 keV/u).

  10. RELATIVISTIC HEAVY ION COLLISIONS: EXPERIMENT

    Energy Technology Data Exchange (ETDEWEB)

    Friedlander, Erwin M.; Heckman, Harry H.

    1982-04-01

    Relativistic heavy ion physics began as a 'no man's land' between particle and nuclear physics, with both sides frowning upon it as 'unclean', because on one hand, hadronic interactions and particle production cloud nuclear structure effects, while on the other, the baryonic environment complicates the interpretation of production experiments. They have attempted to review here the experimental evidence on RHI collisions from the point of view that it represents a new endeavor in the understanding of strong interaction physics. Such an approach appears increasingly justified; first, by the accumulation of data and observations of new features of hadronic interactions that could not have been detected outside a baryonic environment; second, by the maturation of the field owing to the advances made over the past several years in experimental inquiries on particle production by RHI, including pions, kaons, hyperons, and searches for antiprotons; and third, by the steady and progressive increase in the energy and mass ranges of light nuclear beams that have become available to the experiment; indeed the energy range has widened from the {approx} 0.2 to 2 AGeV at the Bevalac to {approx}4 AGeV at Dubna and recently, to the quantum jump in energies to {approx} 1000 equivalent AGeV at the CERN PS-ISR. Accompanying these expansions in the energy frontier are the immediate prospects for very heavy ion beams at the Bevalac up to, and including, 1 AGeV {sup 238}U, thereby extending the 'mass frontier' to its ultimate extent.

  11. High-pressure/low-temperature metamorphism in the collision zone between the Chilenia and Cuyania microcontinents (western Precordillera, Argentina)

    Science.gov (United States)

    Boedo, F. L.; Willner, A. P.; Vujovich, G. I.; Massonne, H.-J.

    2016-12-01

    In central-western Argentina, an Early Paleozoic belt including mafic-ultramafic bodies, marine metasedimentary rocks and high-pressure rocks occur along the western margin of the Precordillera and in the Frontal Cordillera. First pressure-temperature estimates are presented here for low-grade rocks of the southern sector of this belt based on two metasedimentary and one metabasaltic sample from the Peñasco Formation. Peak metamorphic conditions resulted within the range of 345-395 °C and 7.0-9.3 kbar within the high-pressure greenschist facies. The corresponding low metamorphic gradient of 13 °C/km is comparable with subduction related geothermal gradients. Comparison between these results and data from other localities of the same collision zone (Guarguaraz and Colohuincul complexes) confirms a collision between Chilenia and the composite margin of western Gondwana and suggests a stronger crustal thickening in the south of the belt, causing exhumation of more deeply buried sequences. During the Early Paleozoic a long-lived marine sedimentation coupled with the intrusion of MORB-like basalts occurred along a stable margin before the collision event. This contrasts with the almost contemporaneous sedimentation registered during accretion in accretionary prism settings and additionally proves the development of a collision zone along western Precordillera and the eastern Frontal Cordillera as well as the existence of Chilenia as a separate microcontinent.

  12. Old age mortality in Eastern and South-Eastern Asia

    Directory of Open Access Journals (Sweden)

    Danan Gu

    2013-11-01

    Full Text Available Background: Eastern and South-Eastern Asian countries have witnessed a marked decline in old age mortality in recent decades. Yet no studies have investigated the trends and patterns in old age morality and cause-of-death in the region. Objective: We reviewed the trends and patterns of old age mortality and cause-of-death for countries in the region. Methods: We examined data on old age mortality in terms of life expectancy at age 65 and age-specific death rates from the 2012 Revision of the World Population Prospects for 14 countries in the region (China, Hong Kong, Democratic People's Republic of Korea, Indonesia, Japan, Lao People's Democratic Republic, Myanmar, Malaysia, Mongolia, Philippines, Republic of Korea, Singapore, Thailand, and Viet Nam and data on cause-of-death from the WHO for five countries (China, Hong Kong, Japan, Republic of Korea, and Singapore from 1980 to 2010. Results: While mortality transitions in these populations took place in different times, and at different levels of socioeconomic development and living environment, changes in their age patterns and sex differentials in mortality showed certain similarities: women witnessed a similar decline to men in spite of their lower mortality, and young elders had a larger decline than the oldest-old. In all five countries examined for cause-of-death, most of the increases in life expectancy at age 65 in both men and women were attributable to declines in mortality from stroke and heart disease. GDP per capita, educational level, and urbanization explained much of the variations in life expectancy and cause-specific mortality, indicating critical contributions of these basic socioeconomic development indicators to the mortality decline over time in the region. Conclusions: These findings shed light on the relationship between epidemiological transition, changing age patterns of mortality, and improving life expectancy in these populations.

  13. Outcomes of Children Adopted from Eastern Europe

    Science.gov (United States)

    Miller, Laurie; Chan, Wilma; Tirella, Linda; Perrin, Ellen

    2009-01-01

    Behavioral problems are frequent among post-institutionalized Eastern European adoptees. However, risk factors related to outcomes have not been fully delineated. We evaluated 50 Eastern European adoptees, age 8-10 years, with their adoptive families for more than five years. Cognitive and behavioral outcomes and parenting stress were evaluated in…

  14. Modelling of a collision between two smartphones

    Science.gov (United States)

    de Jesus, V. L. B.; Sasaki, D. G. G.

    2016-09-01

    In the predominant approach in physics textbooks, the collision between particles is treated as a black box, where no physical quantity can be measured. This approach becomes even more evident in experimental classes where collisions are the simplest and most common way of applying the theorem of conservation of linear momentum in the asymptotic behavior. In this paper we develop and analyse an experiment on collisions using only two smartphones. The experimental setup is amazingly simple; the two devices are aligned on a horizontal table of lacquered wood, in order to slide more easily. At the edge of one of them a piece of common sponge is glued using double-sided tape. By using a free smartphone application, the values generated by the accelerometer of the two devices in full motion are measured and tabulated. Through numerical iteration, the speed graphs of the smartphones before, during, and after the collision are obtained. The main conclusions were: (i) the demonstration of the feasibility of using smartphones as an alternative to air tracks and electronic sensors employed in a teaching lab, (ii) the possibility of investigating the collision itself, its characteristics and effects; this is the great advantage of the use of smartphones over traditional experiments, (iii) the compatibility of the results with the impulse-momentum theorem, within the margin of uncertainty.

  15. The collision between two hydrogen atoms

    CERN Document Server

    Ray, Hasi

    2013-01-01

    The electron-electron correlation term in two-atomic collision is the most important, most difficult term to obtain the effective interatomic potential. Generally the H and H collision is a four center problem. It is extremely difficult to compute the electron-electron correlation term to include the effect of exchange or antisymmetry between two system electrons exactly. All the two-atomic collision related theoretical data differ from each other due to its difference in approximating the electron-electron correlation term. I invent a trick to evaluate the term exactly. Earlier the positronium (Ps) and H system was easily approximated as a three center problem due to the light mass of Ps. My new code for H-H collision using the ab-initio and exact static-exchange model (SEM) can reproduce exactly the same data of Ps and H system just by using the appropriate atomic parameters. The success of the present trick makes the foundation of a big monument in cold and low energy atomic collision physics. The Feshbach...

  16. Underactuated spacecraft formation reconfiguration with collision avoidance

    Science.gov (United States)

    Huang, Xu; Yan, Ye; Zhou, Yang

    2017-02-01

    Underactuated collision-free controllers are proposed in this paper for multiple spacecraft formation reconfiguration in circular orbits with the loss of either the radial or in-track thrust. A nonlinear dynamical model of underactuated formation flying is introduced, which is then linearized about circular orbits for controllability and feasibility analyses on underactuated formation reconfiguration. By using the inherent dynamics coupling of system states, reduced-order sliding mode controllers are then designed for either case to indirectly stabilize the system trajectories to the desired formations. In consideration of the collision-avoidance requirement, the artificial potential function method is then employed to design novel underactuated collision-avoidance maneuvers. Rigorous proof substantiates the capabilities of such maneuvers in preventing collisions even in the absence of radial or in-track thrust. Furthermore, a Lyapunov-based analysis ensures the asymptotic stability of the overall closed-loop system. Numerical simulations are performed in a J2-perturbed environment to verify the validity of the proposed underactuated control schemes for collision-free reconfiguration.

  17. Collisions of solid ice in planetesimal formation

    Science.gov (United States)

    Deckers, J.; Teiser, J.

    2016-03-01

    We present collision experiments of centimetre projectiles on to decimetre targets, both made up of solid ice, at velocities of 15-45 m s-1 at an average temperature of {T_{avg}}=255.8 ± 0.7 K. In these collisions, the centimetre body gets disrupted and part of it sticks to the target. This behaviour can be observed up to an upper threshold, that depends on the projectile size, beyond which there is no mass transfer. In collisions of small particles, as produced by the disruption of the centimetre projectiles, we also find mass transfer to the target. In this way, the larger body can gain mass, although the efficiency of the initial mass transfer is rather low. These collision results can be applied to planetesimal formation near the snowline, where evaporation and condensation is expected to produce solid ice. In free fall collisions at velocities up to about 7 m s-1, we investigated the threshold to fragmentation and coefficient of restitution of centimetre ice spheres.

  18. Collisions of solid ice in planetesimal formation

    CERN Document Server

    Deckers, J

    2016-01-01

    We present collision experiments of centimetre projectiles on to decimetre targets, both made up of solid ice, at velocities of $15\\,\\mathrm{m\\,s^{-1}}$ to $45\\,\\mathrm{m\\,s^{-1}}$ at an average temperature of $\\mathrm{T_{avg}}=255.8\\pm0.7\\,\\mathrm{K}$. In these collisions the centimetre body gets disrupted and part of it sticks to the target. This behaviour can be observed up to an upper threshold, that depends on the projectile size, beyond which there is no mass transfer. In collisions of small particles, as produced by the disruption of the centimetre projectiles, we also find mass transfer to the target. In this way the larger body can gain mass, although the efficiency of the initial mass transfer is rather low. These collision results can be applied to planetesimal formation near the snowline, where evaporation and condensation is expected to produce solid ice. In free fall collisions at velocities up to about $7\\,\\mathrm{m\\,s^{-1}}$, we investigated the threshold to fragmentation and coefficient of re...

  19. Measurements of Correlation-Enhanced Collision Rates

    Science.gov (United States)

    Anderegg, F.; Dubin, D. H. E.; O'Neil, T. M.; Driscoll, C. F.

    2008-11-01

    We measure the perp-to-parallel collision rate ν| in laser-cooled Magnesium ion plasmas in the strongly-magnetized and correlated regime; and obtain close agreement with the ``Salpeter correlation enhancement'' first studied for fusion in dense plasmas such as stars. The cyclotron energy, like nuclear energy, is released only through rare close-range collisions. These close collisions are suppressed by strong magnetization, because collisional impact distances are rarely as small as a cyclotron radius rc. However, theory predicts that particle correlations reduce this suppression of collisionality, enhancing the rare close collisions by e^γ, where γ≡e^2 / aT is the correlation parameter. We control the plasma temperature over the range 4 0-6 < T < 1eV, giving correlation parameters up to γ 0, with measured collision rates 2 < ν| 2 10^4 sec-1. At low temperatures, the measured ν| are enhanced by up to 10^9 compared to uncorrelated theory, consistent with the predicted correlation enhancement. When the plasma density is reduced from 2 to 0.12 x10^7cm-3, the correlations are eliminated and the measured ν| agree with uncorrelated theory. E.E. Salpeter and H.M. Van Horn, Astrophys. J. 155, 183 (1969). D.H.E. Dubin, Phys. Rev. Lett. 94, 025002 (2005).

  20. Eastern European retailers and wholesalers' buying behaviour

    DEFF Research Database (Denmark)

    Esbjerg, Lars; Stacey, Julia

    1999-01-01

    During the last ten years, retailing in Eastern Europe has undergone considerable changes. The entry of Western European retail chains into Eastern Europe has helped accelerate the distributive trade of Eastern Europe. But what does it take to sell fish and cheese to retailers and wholesalers....... Low prices and favourable terms of payment are most important when retailers in Eastern Europe buy fish and cheese. Then follows the supplier's range of products, trustworthiness of the supplier and product quality. Eastern European wholesalers also rank price and financial conditions as most....... In comparison,Western European retailers prefer doing business with suppliers that are capable of supplying all shops in a chain. Also the question about traceability is decisive.Retailers also prefer doing business with suppliers that are interested in a long-term trade relationship and who are from their own...

  1. HOMED-Homicides Eastern Denmark

    DEFF Research Database (Denmark)

    Colville-Ebeling, Bonnie; Frisch, Morten; Lynnerup, Niels

    2014-01-01

    Background:An introduction to a forensic medical homicide database established at the Department of Forensic Medicine in Copenhagen. Content: The database contains substantial clinical and demographic data obtained in conjunction with medico-legal autopsies of victims and forensic clinical...... examinations of perpetrators in homicide cases in eastern Denmark. Validity and coverage: The database contains information on all homicide cases investigated at the Department of Forensic Medicine in Copenhagen since 1971. Coverage for the catchment area of the department is assumed to be very good because...... of a medico-legal homicide autopsy rate close to 100%. Regional differences might exist however, due to the fact that the catchment area of the department is dominated by the city of Copenhagen. Conclusions: The strength of the database includes a long running time, near complete regional coverage...

  2. Neutrino quantum kinetic equations: The collision term

    Science.gov (United States)

    Blaschke, Daniel N.; Cirigliano, Vincenzo

    2016-08-01

    We derive the collision term relevant for neutrino quantum kinetic equations in the early universe and compact astrophysical objects, displaying its full matrix structure in both flavor and spin degrees of freedom. We include in our analysis neutrino-neutrino processes, scattering and annihilation with electrons and positrons, and neutrino scattering off nucleons (the latter in the low-density limit). After presenting the general structure of the collision terms, we take two instructive limiting cases. The one-flavor limit highlights the structure in helicity space and allows for a straightforward interpretation of the off-diagonal entries in terms of the product of scattering amplitudes of the two helicity states. The isotropic limit is relevant for studies of the early universe: in this case the terms involving spin coherence vanish and the collision term can be expressed in terms of two-dimensional integrals, suitable for computational implementation.

  3. Neutrino Quantum Kinetic Equations: The Collision Term

    CERN Document Server

    Blaschke, Daniel N

    2016-01-01

    We derive the collision term relevant for neutrino quantum kinetic equations in the early universe and compact astrophysical objects, displaying its full matrix structure in both flavor and spin degrees of freedom. We include in our analysis neutrino-neutrino processes, scattering and annihilation with electrons and positrons, and neutrino scattering off nucleons (the latter in the low-density limit). After presenting the general structure of the collision terms, we take two instructive limiting cases. The one-flavor limit highlights the structure in helicity space and allows for a straightforward interpretation of the off-diagonal entries in terms of the product of scattering amplitudes of the two helicity states. The isotropic limit is relevant for studies of the early universe: in this case the terms involving spin coherence vanish and the collision term can be expressed in terms of two-dimensional integrals, suitable for computational implementation.

  4. Application of hydrodynamics to heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Felsberger, Lukas

    2014-12-02

    The Bjorken model is a simple tool for making rough predictions of the hydrodynamic evolution of the thermalized matter created in a heavy ion collision. The advantage of the model clearly lies in its simplicity, rather than accuracy. As it is still used for making rough estimations 'by hand', in this thesis, I investigate in which cases the Bjorken model gives useful results and in which it is not recommended. For central collisions, I show which critical size the nuclei should have so that the Bjorken model can be applied. For non-central collisions, I demonstrate that using Glauber initial conditions combined with the Bjorken evolution, leads to reasonable results up to large impact parameters. Finally, I study the case of a non-ideal (viscous) description of the thermalized matter which leads to strongly differing results if first- or second-order hydrodynamics is applied.

  5. Collision-spike Sputtering of Au Nanoparticles.

    Science.gov (United States)

    Sandoval, Luis; Urbassek, Herbert M

    2015-12-01

    Ion irradiation of nanoparticles leads to enhanced sputter yields if the nanoparticle size is of the order of the ion penetration depth. While this feature is reasonably well understood for collision-cascade sputtering, we explore it in the regime of collision-spike sputtering using molecular-dynamics simulation. For the particular case of 200-keV Xe bombardment of Au particles, we show that collision spikes lead to abundant sputtering with an average yield of 397 ± 121 atoms compared to only 116 ± 48 atoms for a bulk Au target. Only around 31 % of the impact energy remains in the nanoparticles after impact; the remainder is transported away by the transmitted projectile and the ejecta. The sputter yield of supported nanoparticles is estimated to be around 80 % of that of free nanoparticles due to the suppression of forward sputtering.

  6. Chiral Magnetic Effect in Heavy Ion Collisions

    CERN Document Server

    Liao, Jinfeng

    2016-01-01

    The Chiral Magnetic Effect (CME) is a remarkable phenomenon that stems from highly nontrivial interplay of QCD chiral symmetry, axial anomaly, and gluonic topology. It is of fundamental importance to search for the CME in experiments. The heavy ion collisions provide a unique environment where a hot chiral-symmetric quark-gluon plasma is created, gluonic topological fluctuations generate chirality imbalance, and very strong magnetic fields $|\\vec{\\bf B}|\\sim m_\\pi^2$ are present during the early stage of such collisions. Significant efforts have been made to look for CME signals in heavy ion collision experiments. In this contribution we give a brief overview on the status of such efforts.

  7. Chemical Equilibrium in Collisions of Small Systems

    CERN Document Server

    Kraus, I; Oeschler, H; Redlich, K; Wheaton, S

    2007-01-01

    The system-size dependence of particle production in heavy-ion collisions at the top SPS energy is analyzed in terms of the statistical model. A systematic comparison is made of two suppression mechanisms that quantify strange particle yields in ultra-relativistic heavy-ion collisions: the canonical model with strangeness correlation radius determined from the data and the model formulated in the canonical ensemble using chemical off-equilibrium strangeness suppression factor. The system-size dependence of the correlation radius and the thermal parameters are obtained for p-p, C-C, Si-Si and Pb-Pb collisions at sqrt(s_NN) = 17.3 AGeV. It is shown that on the basis of a consistent set of data there is no clear difference between the two suppression patterns. In the present study the strangeness correlation radius was found to exhibit a rather weak dependence on the system size.

  8. Characteristics of Collision, Capacitive Radio Frequency Sheath

    Institute of Scientific and Technical Information of China (English)

    Zhang Yu; DingWanYu; Wang Wenchun; Liu JinYuan; Wang Xiaogang; Liu Yue

    2005-01-01

    A simple collisional radio frequency (rf) sheath fluid model, which is not restricted by the ratio of rf frequency to ion plasma frequency (β=ωrf/ωpi), was established and solved numerically. In the ion balance equation, the effect of the collision on the ion and the ion velocity is assumed to be a direct ratio to ion velocity. The ion energy distributions (IEDs) calculated in the model in comparison with the experimental data [M. A. Sobolewski, J. K. Olthoff, and Y.C. Wang, J. Appl. Phys. 85, 3966 (1999)], proved the validity of the model. And the effect of the collision on the sheath characteristic was obtained and discussed. This paper demonstrates that the collision frequency is another crucial parameter as well as the ratio β to determine the rf sheath characteristics and the shape of IE Ds.

  9. Physics of Ultra-Peripheral Nuclear Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Bertulani, Carlos A.; Klein, Spencer R.; Nystrand, Joakim

    2005-02-02

    Moving highly-charged ions carry strong electromagnetic fields which act as a field of photons. In collisions at large impact parameters, hadronic interactions are not possible, and the ions interact through photon-ion and photon-photon collisions known as ultra-peripheral collisions (UPC). Hadron colliders like the Relativistic Heavy Ion Collider (RHIC), the Tevatron and the Large Hadron Collider (LHC) produce photonuclear and two-photon interactions at luminosities and energies beyond that accessible elsewhere; the LHC will reach a {gamma}p energy ten times that of the Hadron-Electron Ring Accelerator (HERA). Reactions as diverse as the production of anti-hydrogen, photoproduction of the {rho}{sup 0}, transmutation of lead into bismuth and excitation of collective nuclear resonances have already been studied. At the LHC, UPCs can study many types of ''new physics''.

  10. Tilting Uranus without a Collision

    Science.gov (United States)

    Rogoszinski, Zeeve; Hamilton, Douglas P.

    2016-10-01

    The most accepted hypothesis for the origin of Uranus' 98° obliquity is a giant collision during the late stages of planetary accretion. This model requires a single Earth mass object striking Uranus at high latitudes; such events occur with a probability of about 10%. Alternatively, Uranus' obliquity may have arisen from a sequence of smaller impactors which lead to a uniform distribution of obliquities. Here we explore a third model for tilting Uranus using secular spin-orbit resonance theory. We investigate early Solar System configurations in which a secular resonance between Uranus' axial precession frequency and another planet's orbital node precession frequency might occur.Thommes et al. (1999) hypothesized that Uranus and Neptune initially formed between Jupiter and Saturn, and were then kicked outward. In our scenario, Neptune leaves first while Uranus remains behind. As an exterior Neptune slowly migrates outward, it picks up both Uranus and Saturn in spin-orbit resonances (Ward and Hamilton 2004; Hamilton and Ward 2004). Only a distant Neptune has a nodal frequency slow enough to resonate with Uranus' axial precession.This scenario, with diverging orbits, results in resonance capture. As Neptune migrates outward its nodal precession slows. While in resonance, Uranus and Saturn each tilt a bit further, slowing their axial precession rates to continually match Neptune's nodal precession rate. Tilting Uranus to high obliquities takes a few 100 Myrs. This timescale may be too long to hold Uranus captive between Jupiter and Saturn, and we are investigating how to reduce it. We also find that resonance capture is rare if Uranus' initial obliquity is greater than about 10°, as the probability of capture decreases as the planet's initial obliquity increases. We will refine this estimate by quantifying capture statistics, and running accretion simulations to test the likelihood of a low early obliquity. Our preliminary findings show that most assumptions about

  11. Collision statistics in sheared inelastic hard spheres.

    Science.gov (United States)

    Bannerman, Marcus N; Green, Thomas E; Grassia, Paul; Lue, Leo

    2009-04-01

    The dynamics of sheared inelastic-hard-sphere systems is studied using nonequilibrium molecular-dynamics simulations and direct simulation Monte Carlo. In the molecular-dynamics simulations Lees-Edwards boundary conditions are used to impose the shear. The dimensions of the simulation box are chosen to ensure that the systems are homogeneous and that the shear is applied uniformly. Various system properties are monitored, including the one-particle velocity distribution, granular temperature, stress tensor, collision rates, and time between collisions. The one-particle velocity distribution is found to agree reasonably well with an anisotropic Gaussian distribution, with only a slight overpopulation of the high-velocity tails. The velocity distribution is strongly anisotropic, especially at lower densities and lower values of the coefficient of restitution, with the largest variance in the direction of shear. The density dependence of the compressibility factor of the sheared inelastic-hard-sphere system is quite similar to that of elastic-hard-sphere fluids. As the systems become more inelastic, the glancing collisions begin to dominate over more direct, head-on collisions. Examination of the distribution of the times between collisions indicates that the collisions experienced by the particles are strongly correlated in the highly inelastic systems. A comparison of the simulation data is made with direct Monte Carlo simulation of the Enskog equation. Results of the kinetic model of Montanero [J. Fluid Mech. 389, 391 (1999)] based on the Enskog equation are also included. In general, good agreement is found for high-density, weakly inelastic systems.

  12. High energy density in multisoliton collisions

    Science.gov (United States)

    Saadatmand, Danial; Dmitriev, Sergey V.; Kevrekidis, Panayotis G.

    2015-09-01

    Solitons are very effective in transporting energy over great distances and collisions between them can produce high energy density spots of relevance to phase transformations, energy localization and defect formation among others. It is then important to study how energy density accumulation scales in multisoliton collisions. In this study, we demonstrate that the maximal energy density that can be achieved in collision of N slowly moving kinks and antikinks in the integrable sine-Gordon field, remarkably, is proportional to N2, while the total energy of the system is proportional to N . This maximal energy density can be achieved only if the difference between the number of colliding kinks and antikinks is minimal, i.e., is equal to 0 for even N and 1 for odd N and if the pattern involves an alternating array of kinks and antikinks. Interestingly, for odd (even) N the maximal energy density appears in the form of potential (kinetic) energy, while kinetic (potential) energy is equal to zero. The results of the present study rely on the analysis of the exact multisoliton solutions for N =1 ,2 , and 3 and on the numerical simulation results for N =4 ,5 ,6 , and 7. The effect of weak Hamiltonian and non-Hamiltonian perturbations on the maximal energy density in multikink collisions is also discussed as well as that of the collision relative phase. Based on these results one can speculate that the soliton collisions in the sine-Gordon field can, in principle, controllably produce very high energy density. This can have important consequences for many physical phenomena described by the Klein-Gordon equations.

  13. Newton's cradle undone: Experiments and collision models for the normal collision of three solid spheres

    Science.gov (United States)

    Donahue, C. M.; Hrenya, C. M.; Zelinskaya, A. P.; Nakagawa, K. J.

    2008-11-01

    Using an apparatus inspired by Newton's cradle, the simultaneous, normal collision between three solid spheres is examined. Namely, an initially touching, motionless pair of "target" particles (doublet) is impacted on one end by a third "striker" particle. Measurements of postcollisional velocities and collision durations are obtained via high-speed photography and an electrical circuit, respectively. Contrary to intuition, the expected Newton's cradle outcome of a motionless, touching particle pair at the bottom of the pendulum arc is not observed in either case. Instead, the striker particle reverses its direction and separates from the middle particle after collision. This reversal is not observed, however, if the target particles are separated by a small distance (not in contact) initially, although a separation still occurs between the striker and middle particle after the collision, with both particles traveling in the same direction. For the case of initially touching target particles, contact duration measurements indicate that the striker separates from the three particles before the two target particles separate. However, when the targets are slightly separated, a three-particle collision is never observed, and the collision is, in fact, a series of two-body collisions. A subsequent implementation of a variety of hard-sphere and soft-sphere collision models indicates that a three-body (soft-sphere) treatment is essential for predicting the velocity reversal, consistent with the experimental findings. Finally, a direct comparison between model predictions and measurements of postcollisional velocities and contact durations provides a gauge of the relative merits of existing collision models for three-body interactions.

  14. Collision detection and untangling for surgical robotic manipulators.

    Science.gov (United States)

    Morvan, Tangui; Martinsen, Magnar; Reimers, Martin; Samset, Eigil; Elle, Ole Jakob

    2009-09-01

    Robotic-assisted minimally invasive surgery provides several advantages over traditional surgery; however, it also has several drawbacks, such as possible collisions between the robotic arms and a limited field of view. A generic method for tracking the configuration of a surgical manipulator in real time is presented. It is coupled with a collision detection and dynamic simulation algorithm, allowing the operator to detect collisions between robotic arms before they happen and presenting the best possible untangling direction to get out of collisions. Our algorithm successfully tracks the configuration of the Zeus surgical system and accurately detects possible collisions in real time. A pilot study on our system proved its efficiency in reducing the duration and severity of collisions, at the price of longer completion times. Our system helps alleviate the collision problem by reducing the time in collision.

  15. SOME COLLISION PROCESSES IN PLASMAS WITH HIGHER TEMPERATURE AND DENSITY

    Institute of Scientific and Technical Information of China (English)

    KazuoTakayanagi

    1990-01-01

    Some collision processes important in hot and dense plasmas are discussed.Recent calculation of secondary electron velocity distribution in ionizing collision between an electron and a multiply-charged ion is reported.

  16. Multiobjective Optimization Based Vessel Collision Avoidance Strategy Optimization

    Directory of Open Access Journals (Sweden)

    Qingyang Xu

    2014-01-01

    Full Text Available The vessel collision accidents cause a great loss of lives and property. In order to reduce the human fault and greatly improve the safety of marine traffic, collision avoidance strategy optimization is proposed to achieve this. In the paper, a multiobjective optimization algorithm NSGA-II is adopted to search for the optimal collision avoidance strategy considering the safety as well as economy elements of collision avoidance. Ship domain and Arena are used to evaluate the collision risk in the simulation. Based on the optimization, an optimal rudder angle is recommended to navigator for collision avoidance. In the simulation example, a crossing encounter situation is simulated, and the NSGA-II searches for the optimal collision avoidance operation under the Convention on the International Regulations for Preventing Collisions at Sea (COLREGS. The simulation studies exhibit the validity of the method.

  17. Intelligent Sensor Tasking for Space Collision Mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Olivier, S S; Pertica, A J; Henderson, J R

    2010-04-01

    Orbital collisions pose a hazard to space operations. Using a high performance computer modeling and simulation environment for space situational awareness, we explore a new paradigm for improving satellite conjunction analysis by obtaining more precise orbital information only for those objects that pose a collision risk greater than a defined threshold to a specific set of satellites during a specified time interval. In particular, we assess the improvement in the quality of the conjunction analysis that can be achieved using a distributed network of ground-based telescopes.

  18. Applied atomic and collision physics special topics

    CERN Document Server

    Massey, H S W; Bederson, Benjamin

    1982-01-01

    Applied Atomic Collision Physics, Volume 5: Special Topics deals with topics on applications of atomic collisions that were not covered in the first four volumes of the treatise. The book opens with a chapter on ultrasensitive chemical detectors. This is followed by separate chapters on lighting, magnetohydrodynamic electrical power generation, gas breakdown and high voltage insulating gases, thermionic energy converters, and charged particle detectors. Subsequent chapters deal with the operation of multiwire drift and proportional chambers and streamer chambers and their use in high energy p

  19. Plasma Polarization Spectroscopy and collision cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Takashi; Nakai, Manabu [Dept. of Engineering Physics and Mechanics, Graduate School of Engineering, Kyoto Univ. (Japan)

    2000-01-01

    In Plasma Polarization Spectroscopy (PPS), we observe the polarized spectral lines emitted from a plasma. For berylliumlike oxygen lines from a tokamak plasma the polarization feature is interpreted as due to the anisotropic velocity distribution of electrons which excite the ions. In this interpretation in terms of the population-alignment collisional-radiative (PACR) model various collision processes are involved concerning the population and the alignment, e.g., transfer of the alignment, and the coherence by collisional excitation and production of an alignment from a population by elastic collisions. These latter processes are little known so far. (author)

  20. Spatial Analysis Methods of Road Traffic Collisions

    DEFF Research Database (Denmark)

    Loo, Becky P. Y.; Anderson, Tessa Kate

    Spatial Analysis Methods of Road Traffic Collisions centers on the geographical nature of road crashes, and uses spatial methods to provide a greater understanding of the patterns and processes that cause them. Written by internationally known experts in the field of transport geography, the book...... outlines the key issues in identifying hazardous road locations (HRLs), considers current approaches used for reducing and preventing road traffic collisions, and outlines a strategy for improved road safety. The book covers spatial accuracy, validation, and other statistical issues, as well as link...

  1. Photons from nuclear collisions at RHIC energies

    CERN Document Server

    Gale, Charles; Frodermann, Evan; Heinz, Ulrich

    2008-01-01

    We model the hot and dense strongly interacting mater produced in high energy heavy ion collisions using relativistic hydrodynamics. Several different sources of real photons produced during these collisions are considered and their relative importance is assessed. We include contributions from QCD jets, which are allowed to loose and gain energy as they proceed through the hot matter. This is treated within the AMY formalism. We obtain photon spectra, R_{AA}, and v_2 in agreement with measurements performed by the PHENIX collaboration.

  2. Fluid moments of the Landau collision operator

    CERN Document Server

    Hirvijoki, Eero; Pfefferlé, David; Comisso, Luca; Candy, Jeff; Bhattacharjee, Amitava

    2016-01-01

    One important problem in plasma physics is the lack of an accurate and complete description of Coulomb collisions in associated fluid models. To shed light on the problem, this Letter introduces an integral identity involving the multi-dimensional Hermite tensor polynomials and presents a method for computing exact expressions for the fluid moments of the nonlinear Landau collision operator. The proposed methodology provides a systematic and rigorous means of extending the validity of fluid models that have an underlying inverse-square force particle dynamics to weakly collisional and strong flow regimes.

  3. Regular collision of dilatonic inflating branes

    CERN Document Server

    Leeper, E; Maartens, R

    2005-01-01

    We demonstrate that a two brane system with a bulk scalar field driving power-law inflation on the branes has an instability in the radion. We solve for the resulting trajectory of the brane, and find that the instability can lead to collision. Brane quantities such as the scale factor are shown to be regular at this collision. In addition we describe the system using a low energy expansion. The low energy expansion accurately reproduces the known exact solution, but also identifies an alternative solution for the bulk metric and brane trajectory.

  4. Collective flow in Au + Au collisions

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, H.G.; EOS Collaboration

    1994-05-01

    Based on a preliminary sample of Au + Au collisions in the EOS time projection chamber at the Bevalac, we study sideward flow as a function of bombarding energy between 0.25A GeV and 1.2A GeV. We focus on the increase in in-plane transverse momentum per nucleon with fragment mass. We also find event shapes to be close to spherical in the most central collisions, independent of bombarding energy and fragment mass up to {sup 4}He.

  5. A numerical 4D Collision Risk Model

    Science.gov (United States)

    Schmitt, Pal; Culloch, Ross; Lieber, Lilian; Kregting, Louise

    2017-04-01

    With the growing number of marine renewable energy (MRE) devices being installed across the world, some concern has been raised about the possibility of harming mobile, marine fauna by collision. Although physical contact between a MRE device and an organism has not been reported to date, these novel sub-sea structures pose a challenge for accurately estimating collision risks as part of environmental impact assessments. Even if the animal motion is simplified to linear translation, ignoring likely evasive behaviour, the mathematical problem of establishing an impact probability is not trivial. We present a numerical algorithm to obtain such probability distributions using transient, four-dimensional simulations of a novel marine renewable device concept, Deep Green, Minesto's power plant and hereafter referred to as the 'kite' that flies in a figure-of-eight configuration. Simulations were carried out altering several configurations including kite depth, kite speed and kite trajectory while keeping the speed of the moving object constant. Since the kite assembly is defined as two parts in the model, a tether (attached to the seabed) and the kite, collision risk of each part is reported independently. By comparing the number of collisions with the number of collision-free simulations, a probability of impact for each simulated position in the cross- section of the area is considered. Results suggest that close to the bottom, where the tether amplitude is small, the path is always blocked and the impact probability is 100% as expected. However, higher up in the water column, the collision probability is twice as high in the mid line, where the tether passes twice per period than at the extremes of its trajectory. The collision probability distribution is much more complex in the upper end of the water column, where the kite and tether can simultaneously collide with the object. Results demonstrate the viability of such models, which can also incorporate empirical

  6. Horndeski/Galileon in High Energy Collisions

    CERN Document Server

    Latosh, B N

    2016-01-01

    Horndeski/Galileons may be considered as a proper generalization of General Relativity in high energy regime. Thus one may search for manifestation of Galileons interaction in collision experiments. In this paper we give arguments supporting this thesis. Galileon scalar field do not interact with matter via Standard Model interactions, we discuss a mechanism that allows Galileons to have influence on particle collisions. We give reasons to narrow the whole class of Horndeski/Galileons models to one particular term - John term from Fab Four subclass - for this particular issue. We were able to establish the constraint on the model coupling constant.

  7. Guide to the collision avoidance rules

    CERN Document Server

    Cockcroft, A N

    2004-01-01

    A Guide to the Collision Avoidance Rules is the essential reference to the safe operation of all vessels at sea. Published continuously since 1965, this respected and expert guide is the classic text for all who need to, practically and legally, understand and comply with the Rules. This sixth edition incorporates all of the amendments to the International Regulations for Preventing Collisions at Sea which came into force in November 2003.The books sets out all of the Rules with clear explanation of their meaning, and gives detailed examples of how the rules have been used in practice

  8. Plasmas applied atomic collision physics, v.2

    CERN Document Server

    Barnett, C F

    1984-01-01

    Applied Atomic Collision Physics, Volume 2: Plasmas covers topics on magnetically confined plasmas. The book starts by providing the history of fusion research and describing the various approaches in both magnetically and inertially confined plasmas. The text then gives a general discussion of the basic concepts and properties in confinement and heating of a plasma. The theory of atomic collisions that result in excited quantum states, particularly highly ionized impurity atoms; and diverse diagnostic topics such as emission spectra, laser scattering, electron cyclotron emission, particle bea

  9. Centrality determination in pPb collisions with CMS

    Energy Technology Data Exchange (ETDEWEB)

    Tuo, Shengquan

    2014-06-15

    Centrality is very important for defining the collision system size in heavy ion collisions. It provides a tool for selecting events according to cross section in a similar way in different experiments and facilitates the comparison of experimental results and theoretical calculations. The progress of centrality determination in pPb collisions at CMS is presented. The choice of variables used for event classification will be discussed. Methods for the estimation of the number of nucleon–nucleon collisions will be shown.

  10. On Rational Design of Double Hull Tanker Structures against Collision

    DEFF Research Database (Denmark)

    Paik, Jeom Kee; Chung, Jang Young; Choe, Ich Hung

    1999-01-01

    in the present study were (i) developing a framework for the collision design procedure for double hull tanker structures, (ii) experimental investigation of the structural crashworthiness of the collided vessels in collision or stranding, using double skinned structural models, (iii) validation of the special...... be useful for the rational design of new double hull tanker side structures against ship collision to reduced the risk of oil pollution and for the collision resistance evaluation of existing double hull tanker structures....

  11. Gluon field fluctuations in nuclear collisions: Multiplicity and eccentricity distributions

    CERN Document Server

    Schenke, Björn; Venugopalan, Raju

    2013-01-01

    We discuss different sources of fluctuations in nuclear collisions and their realization in the IP-Glasma model. We present results for multiplicity distributions in p+p and p+A collisions and compare eccentricity distributions in A+A collisions to the flow harmonic distributions in 10 centrality classes measured by the ATLAS collaboration.

  12. Some properties of the central heavy ion collisions

    CERN Document Server

    Wazir, Z; Khan, E U; Haseeb, Mahnaz Q; Ajaz, M; Khan, K H

    2009-01-01

    Some experimental results are discussed in connection with the properties of the central heavy ion collisions. These experiments indicate the regime changes and saturation at some values of the centrality. This phenomenon is considered to be a signal of the percolation cluster formation in heavy ion collisions at high energies. Keywords: heavy ion collisions, theoretical models, centrality, phase transition.

  13. 14 CFR 121.356 - Collision avoidance system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Collision avoidance system. 121.356 Section... Collision avoidance system. Effective January 1, 2005, any airplane you operate under this part must be equipped and operated according to the following table: Collision Avoidance Systems If you operate...

  14. 14 CFR 437.65 - Collision avoidance analysis.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Collision avoidance analysis. 437.65..., DEPARTMENT OF TRANSPORTATION LICENSING EXPERIMENTAL PERMITS Safety Requirements § 437.65 Collision avoidance... permittee must obtain a collision avoidance analysis from United States Strategic Command. (b) The...

  15. 14 CFR 417.231 - Collision avoidance analysis.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Collision avoidance analysis. 417.231..., DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.231 Collision avoidance analysis. (a) General. A flight safety analysis must include a collision avoidance analysis...

  16. 14 CFR 125.224 - Collision avoidance system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Collision avoidance system. 125.224 Section... Requirements § 125.224 Collision avoidance system. Effective January 1, 2005, any airplane you operate under this part 125 must be equipped and operated according to the following table: Collision...

  17. Eastern Renewable Generation Integration Study

    Energy Technology Data Exchange (ETDEWEB)

    Bloom, Aaron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Townsend, Aaron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Palchak, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Novacheck, Joshua [National Renewable Energy Lab. (NREL), Golden, CO (United States); King, Jack [RePPAE LLC, Wexford, PA (United States); Barrows, Clayton [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ibanez, Eduardo [GE Energy, Denver, CO (United States); O' Connell, Matthew [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jordan, Gary [GE Energy, Denver, CO (United States); Roberts, Billy [National Renewable Energy Lab. (NREL), Golden, CO (United States); Draxl, Caroline [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gruchalla, Kenny [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-08-01

    The Eastern Interconnection (EI) is one of the largest power systems in the world, and its size and complexity have historically made it difficult to study in high levels of detail in a modeling environment. In order to understand how this system might be impacted by high penetrations (30% of total annual generation) of wind and solar photovoltaic (PV) during steady state operations, the National Renewable Energy Laboratory (NREL) and the U.S. Department of Energy (DOE) conducted the Eastern Renewable Generation Integration Study (ERGIS). This study investigates certain aspects of the reliability and economic efficiency problem faced by power system operators and planners. Specifically, the study models the ability to meet electricity demand at a 5-minute time interval by scheduling resources for known ramping events, while maintaining adequate reserves to meet random variation in supply and demand, and contingency events. To measure the ability to meet these requirements, a unit commitment and economic dispatch (UC&ED) model is employed to simulate power system operations. The economic costs of managing this system are presented using production costs, a traditional UC&ED metric that does not include any consideration of long-term fixed costs. ERGIS simulated one year of power system operations to understand regional and sub-hourly impacts of wind and PV by developing a comprehensive UC&ED model of the EI. In the analysis, it is shown that, under the study assumptions, generation from approximately 400 GW of combined wind and PV capacity can be balanced on the transmission system at a 5-minute level. In order to address the significant computational burdens associated with a model of this detail we apply novel computing techniques to dramatically reduce simulation solve time while simultaneously increasing the resolution and fidelity of the analysis. Our results also indicate that high penetrations of wind and PV (collectively variable generation (VG

  18. High energy photon-photon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Zerwas, P.M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    1994-07-01

    The collisions of high energy photons produced at a electron-positron collider provide a comprehensive laboratory for testing QCD, electroweak interactions and extensions of the standard model. The luminosity and energy of the colliding photons produced by back-scattering laser beams is expected to be comparable to that of the primary e{sup +}e{sup {minus}} collisions. In this overview, we shall focus on tests of electroweak theory in photon-photon annihilation, particularly {gamma}{gamma} {yields} W{sup +}W{sup {minus}}, {gamma}{gamma} {yields} Higgs bosons, and higher-order loop processes, such as {gamma}{gamma} {yields} {gamma}{gamma}, Z{gamma} and ZZ. Since each photon can be resolved into a W{sup +}W{sup minus} pair, high energy photon-photon collisions can also provide a remarkably background-free laboratory for studying WW collisions and annihilation. We also review high energy {gamma}{gamma} tests of quantum chromodynamics, such as the scaling of the photon structure function, t{bar t} production, mini-jet processes, and diffractive reactions.

  19. QCD in hadron-hadron collisions

    Energy Technology Data Exchange (ETDEWEB)

    Albrow, M.

    1997-03-01

    Quantum Chromodynamics provides a good description of many aspects of high energy hadron-hadron collisions, and this will be described, along with some aspects that are not yet understood in QCD. Topics include high E{sub T} jet production, direct photon, W, Z and heavy flavor production, rapidity gaps and hard diffraction.

  20. The way to collisions, step by step

    CERN Multimedia

    2009-01-01

    While the LHC sectors cool down and reach the cryogenic operating temperature, spirits are warming up as we all eagerly await the first collisions. No reason to hurry, though. Making particles collide involves the complex manoeuvring of thousands of delicate components. The experts will make it happen using a step-by-step approach.

  1. On wounded constituents in nuclear collisions

    CERN Document Server

    Bozek, Piotr; Rybczynski, Maciej

    2016-01-01

    In this talk we summarize the main results of our recent paper, Phys. Rev. C94, 014902, where we explore predictions of the wounded quark model for particle production and the properties of the initial state formed in ultra-relativistic collisions of atomic nuclei.

  2. High energy nuclear collisions: Theory overview

    Indian Academy of Sciences (India)

    R J Fries

    2010-08-01

    We review some basic concepts of relativistic heavy-ion physics and discuss our understanding of some key results from the experimental program at the relativistic heavy-ion collider (RHIC). We focus in particular on the early time dynamics of nuclear collisions, some result from lattice QCD, hard probes and photons.

  3. LHC Report: LHC smashes collision records

    CERN Multimedia

    Sarah Charley

    2016-01-01

    The Large Hadron Collider is now producing more than a billion proton-proton collisions per second.   The LHC is colliding protons at a faster rate than ever before: approximately 1 billion times per second. Since April 2016, the LHC has delivered more than 30 inverse femtobarns (fb-1) to both ATLAS and CMS. This means that around 2.4 quadrillion (2.4 million billion) collisions have been seen by each of the experiments this year. The inverse femtobarn is the unit of measurement for integrated luminosity, indicating the cumulative number of potential collisions. This compares with the total of 33.2 fb-1 produced between 2010 and 2015. The unprecedented performance this year is the result of both the incremental increases in collision rate and the sheer amount of time the LHC has been up and running. This comes after a slow start-up in 2015, when scientists and engineers still needed to learn how to operate the machine at a much higher energy. “With more energy, the machine is much more sen...

  4. Cell Biology: Microtubule Collisions to the Rescue.

    Science.gov (United States)

    Gardner, Melissa K

    2016-12-19

    The proper regulation of microtubule lengths is fundamental to their cellular function. New work now reports that the collision of a growing microtubule end with another object, such as a microtubule, can contribute to the regulation of microtubule lengths by leaving behind damage that ultimately acts to stabilize the microtubule network. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Positron production in collision of heavy nuclei

    CERN Document Server

    Khriplovich, I B

    2016-01-01

    We consider the electromagnetic production of positron in collision of slow heavy nuclei, with the simultaneously produced electron captured by one of the nuclei. The cross-section of the discussed process exceeds essentially the cross-section of $e^+e^-$ production.

  6. The quarkonium saga in heavy ion collisions

    CERN Document Server

    Tserruya, Itzhak

    2013-01-01

    J/psi suppression was proposed more than 25 years ago as an unambiguous signature for the formation of the Quark Gluon Plasma in relativistic heavy ion collisions. After intensive efforts, both experimental and theoretical, the quarkonium saga remains exciting, producing surprising results and not fully understood. This talk focuses on recent results on quarkonium production at RHIC and the LHC.

  7. Electron acceleration during streamer collisions in air

    DEFF Research Database (Denmark)

    Köhn, Christoph; Chanrion, Olivier; Neubert, Torsten

    2017-01-01

    during collisions of negative and a positive streamers. To explore this process, we have conducted the first self-consistent particle simulations of streamer encounters. Our simulation model is a 2-D, cylindrically symmetric, particle-in-cell code tracing the electron dynamics and solving the space...

  8. Embedding initial data for black hole collisions

    CERN Document Server

    Romano, J D; Romano, Joseph D; Price, Richard H

    1994-01-01

    We discuss isometric embedding diagrams for the visualization of initial data for the problem of the head-on collision of two black holes. The problem of constructing the embedding diagrams is explicitly presented for the best studied initial data, the Misner geometry. We present a partial solution of the embedding diagrams and discuss issues related to completing the solution.

  9. Fan Affinity Laws from a Collision Model

    Science.gov (United States)

    Bhattacharjee, Shayak

    2012-01-01

    The performance of a fan is usually estimated using hydrodynamical considerations. The calculations are long and involved and the results are expressed in terms of three affinity laws. In this paper we use kinetic theory to attack this problem. A hard sphere collision model is used, and subsequently a correction to account for the flow behaviour…

  10. Relativistic Hydrodynamics for Heavy-Ion Collisions

    Science.gov (United States)

    Ollitrault, Jean-Yves

    2008-01-01

    Relativistic hydrodynamics is essential to our current understanding of nucleus-nucleus collisions at ultrarelativistic energies (current experiments at the Relativistic Heavy Ion Collider, forthcoming experiments at the CERN Large Hadron Collider). This is an introduction to relativistic hydrodynamics for graduate students. It includes a detailed…

  11. Quarkonium production in heavy-ion collisions

    Directory of Open Access Journals (Sweden)

    Arnaldi Roberta

    2014-03-01

    Full Text Available The production of quarkonium states plays a crucial role among the probes to investigate the formation of the plasma of quarks and gluons (QGP in heavy-ion collisions. A review of the charmonium and bottomonium production, mainly focussing on the latest results from the LHC experiments, is presented.

  12. Elliptic flow at different collision stages

    NARCIS (Netherlands)

    Dubla, Andrea

    2016-01-01

    ALICE (A Large Ion Collider Experiment) is one of the four main experiments at the Large Hadron Collider (LHC) optimized for the study of heavy-ion collisions. The prime aim of the experiment is to study in detail the behaviour of nuclear matter at high densities and temperatures. In ALICE also prot

  13. Efficient Collision Detection in a Simulated Hydrocyclone

    NARCIS (Netherlands)

    Eijkeren, van D.F.; Krebs, T.; Hoeijmakers, H.W.M.

    2015-01-01

    Hydrocyclones enhance oil–water separation efficiency compared to conventional separation methods. An efficient collision detection scheme with Np ln Np dependency on the number of particles is proposed. The scheme is developed to investigate the importance of particle–particle interaction for flow

  14. Primordial Particles; Collisions of Inelastic Particles

    Science.gov (United States)

    Sagi, George

    2011-03-01

    Three-dimensional matter is not defined by Euclidian or Cartesian geometries. Newton's and Einstein's laws are related to the motions of elastic masses. The study of collisions of inelastic particles opens up new vistas in physics. The present article reveals how such particles create clusters composed of various numbers of particles. The Probability of each formation, duplets, triplets, etc. can be calculated. The particles are held together by a binding force, and depending upon the angles of collisions they may also rotate around their center of geometry. Because of these unique properties such inelastic particles are referred to as primordial particles, Pp. When a given density of Pp per cubic space is given, then random collisions create a field. The calculation of the properties of such primordial field is very complex and beyond the present study. However, the angles of collisions are infinite in principle, but the probabilities of various cluster sizes are quantum dependent. Consequently, field calculations will require new complex mathematical methods to be discovered yet.

  15. THE PHYSICAL MECHANISM OF COLLISION BETWEEN SOLITONS

    Institute of Scientific and Technical Information of China (English)

    张卓; 唐翌; 颜晓红

    2001-01-01

    An easy and general way to access more complex soliton phenomena is introduced in this paper. The collisionprocess between two solitons of the KdV equation is investigated in great detail with this novel approach, which is different from the sophisticated method of inverse scattering transformation. A more physical and transparent picture describing the collision of solitons is presented.

  16. Collision-based mechanics of bipedal hopping.

    Science.gov (United States)

    Gutmann, Anne K; Lee, David V; McGowan, Craig P

    2013-08-23

    The muscle work required to sustain steady-speed locomotion depends largely upon the mechanical energy needed to redirect the centre of mass and the degree to which this energy can be stored and returned elastically. Previous studies have found that large bipedal hoppers can elastically store and return a large fraction of the energy required to hop, whereas small bipedal hoppers can only elastically store and return a relatively small fraction. Here, we consider the extent to which large and small bipedal hoppers (tammar wallabies, approx. 7 kg, and desert kangaroo rats, approx. 0.1 kg) reduce the mechanical energy needed to redirect the centre of mass by reducing collisions. We hypothesize that kangaroo rats will reduce collisions to a greater extent than wallabies since kangaroo rats cannot elastically store and return as high a fraction of the mechanical energy of hopping as wallabies. We find that kangaroo rats use a significantly smaller collision angle than wallabies by employing ground reaction force vectors that are more vertical and center of mass velocity vectors that are more horizontal and thereby reduce their mechanical cost of transport. A collision-based approach paired with tendon morphometry may reveal this effect more generally among bipedal runners and quadrupedal trotters.

  17. Fan Affinity Laws from a Collision Model

    Science.gov (United States)

    Bhattacharjee, Shayak

    2012-01-01

    The performance of a fan is usually estimated using hydrodynamical considerations. The calculations are long and involved and the results are expressed in terms of three affinity laws. In this paper we use kinetic theory to attack this problem. A hard sphere collision model is used, and subsequently a correction to account for the flow behaviour…

  18. Heavy quark production in pp collisions

    Energy Technology Data Exchange (ETDEWEB)

    McGaughey, P.L. [Los Alamos National Lab., NM (United States); Quack, E. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany); Ruuskanen, P.V. [Univ. of Helsinki (Finland)]|[Univ. of Jyvaeskylae (Finland)] [and others

    1995-07-01

    A systematic study of the inclusive single heavy quark and heavy-quark pair production cross sections in pp collisions is presented for RHIC and LHC energies. We compare with existing data when possible. The dependence of the rates on the renormalization and factorization scales is discussed. Predictions of the cross sections are given for two different sets of parton distribution functions.

  19. The evolution of runaway stellar collision products

    CERN Document Server

    Glebbeek, E; de Mink, S E; Pols, O R; Zwart, S F Portegies

    2009-01-01

    In the cores of young dense star clusters repeated stellar collisions involving the same object can occur, which has been suggested to lead to the formation of an intermediate-mass black hole. In order to verify this scenario we compute the detailed evolution of the merger remnant of three sequences. We follow the evolution until the onset of carbon burning and estimate the final remnant mass to determine the ultimate fate of a runaway merger sequence. We use a detailed stellar evolution code to follow the evolution of the collision product. At each collision, we mix the two colliding stars, taking account of mass loss during the collision. During the stellar evolution we apply mass loss rates from the literature, as appropriate for the evolutionary stage of the merger remnant. We compute models for high ($Z=0.02$) and low ($Z=0.001$) metallicity to quantify metallicity effects. We find that the merger remnant becomes a Wolf-Rayet star before the end of core hydrogen burning. Mass loss from stellar winds domi...

  20. Fast Collision Attack on MD5

    NARCIS (Netherlands)

    M.M.J. Stevens (Marc)

    2006-01-01

    textabstractIn this paper, we present an improved attack algorithm to find two-block collisions of the hash function MD5. The attack uses the same differential path of MD5 and the set of sufficient conditions that was presented by Wang et al. We present a new technique which allows us to

  1. Rapidity Correlation Structure in Nuclear Collisions

    Science.gov (United States)

    Zin, Christopher; Gavin, Sean; Moschelli, George

    2016-09-01

    The forces that drive the nuclear collision system towards local thermal equilibrium leave few observable traces. Heavy ion experiments report a range of features widely attributed to the hydrodynamic flow of a near-equilibrium quark gluon plasma. In particular, measurements of azimuthal anisotropy provide the most comprehensive support for the hydrodynamic description of these systems. In search of the source of this flow, we turned to smaller proton-proton, proton-nucleus and deuterium-nucleus collisions, expecting to find this effect absent. Instead, these collisions show an azimuthal anisotropy that is comparable to the larger ion-ion systems. How can we learn about the mechanisms that give rise to hydrodynamics if every available collision system exhibits flow? We show that measurements of the rapidity dependence of transverse momentum correlations can be used to determine the characteristic time τπ that dictates the rate of isotropization of the stress energy tensor, as well as the shear viscosity ν = η / sT . We formulate methods for computing these correlations using second order dissipative hydrodynamics with noise. Current data are consistent with τπ / ν 10 but targeted measurements can improve this precision. NSF PHY-1207687.

  2. On wounded constituents in nuclear collisions

    Science.gov (United States)

    Bożek, Piotr; Broniowski, Wojciech; Rybczyński, Maciej

    2017-04-01

    In this talk we summarize the main results of our recent paper [1], where we explore predictions of the wounded quark model for particle production and the properties of the initial state formed in ultra-relativistic collisions of atomic nuclei. Presented by M. Rybczyński

  3. Fast Collision Attack on MD5

    NARCIS (Netherlands)

    Stevens, M.M.J.

    2006-01-01

    In this paper, we present an improved attack algorithm to find two-block collisions of the hash function MD5. The attack uses the same differential path of MD5 and the set of sufficient conditions that was presented by Wang et al. We present a new technique which allows us to deterministically fulfi

  4. Conservative discretization of the Landau collision integral

    CERN Document Server

    Hirvijoki, Eero

    2016-01-01

    We describe a density, momentum, and energy conserving discretization of the nonlinear Landau collision integral. Our algorithm is suitable for both the finite-element and discontinuous Galerkin methods and does not require structured meshes. The conservation laws for the discretization are proven algebraically and demonstrated numerically for an axially symmetric nonlinear relaxation problem.

  5. Electron-Atom Collisions in Gases

    Science.gov (United States)

    Kraftmakher, Yaakov

    2013-01-01

    Electron-atom collisions in gases are an aspect of atomic physics. Three experiments in this field employing a thyratron are described: (i) the Ramsauer-Townsend effect, (ii) the excitation and ionization potentials of xenon and (iii) the ion-electron recombination after interrupting the electric discharge.

  6. Strangeness production in AA and pp collisions

    Energy Technology Data Exchange (ETDEWEB)

    Castorina, Paolo [Universita di Catania, Dipartimento di Fisica ed Astronomia, Catania (Italy); INFN, Catania (Italy); Satz, Helmut [Universitaet Bielefeld, Fakultaet fuer Physik, Bielefeld (Germany)

    2016-07-15

    Boost-invariant hadron production in high-energy collisions occurs in causally disconnected regions of finite space-time size. As a result, globally conserved quantum numbers (charge, strangeness, baryon number) are conserved locally in spatially restricted correlation clusters. Their size is determined by two time scales: the equilibration time specifying the formation of a quark-gluon plasma, and the hadronization time, specifying the onset of confinement. The expected values for these scales provide the theoretical basis for the suppression observed for strangeness production in elementary interactions (pp, e{sup +}e{sup -}) below LHC energies. In contrast, the space-time superposition of individual collisions in high-energy heavy-ion interactions leads to higher energy densities, resulting in much later hadronization and hence much larger hadronization volumes. This largely removes the causality constraints and results in an ideal hadronic resonance gas in full chemical equilibrium. In the present paper, we determine the collision energies needed for that; we also estimate when pp collisions reach comparable hadronization volumes and thus determine when strangeness suppression should disappear there as well. (orig.)

  7. Electron-Atom Collisions in Gases

    Science.gov (United States)

    Kraftmakher, Yaakov

    2013-01-01

    Electron-atom collisions in gases are an aspect of atomic physics. Three experiments in this field employing a thyratron are described: (i) the Ramsauer-Townsend effect, (ii) the excitation and ionization potentials of xenon and (iii) the ion-electron recombination after interrupting the electric discharge.

  8. Updated Vertical Extent of Collision Damage

    DEFF Research Database (Denmark)

    Tagg, R.; Bartzis, P.; Papanikolaou, P.

    2002-01-01

    The probabilistic distribution of the vertical extent of collision damage is an important and somewhat controversial component of the proposed IMO harmonized damage stability regulations for cargo and passenger ships. The only pre-existing vertical distribution, currently used in the international...

  9. Collisions of antiprotons with hydrogen molecular ions

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Saenz, Alejandro

    2009-01-01

    Time-dependent close-coupling calculations of the ionization and excitation cross section for antiproton collisions with molecular hydrogen ions are performed in an impact energy range from 0.5 keV to 10 MeV. The Born-Oppenheimer and Franck-Condon approximations as well as the impact parameter...

  10. Probability of Grounding and Collision Events

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup

    1996-01-01

    To quantify the risks involved in ship traffic, rational criteria for collision and grounding accidents have to be developed. This implies that probabilities as well as inherent consequences have to be analyzed and assessed.The present notes outline a method for evaluation of the probability...

  11. Probability of Grounding and Collision Events

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup

    1996-01-01

    To quantify the risks involved in ship traffic, rational criteria for collision and grounding accidents are developed. This implies that probabilities as well as inherent consequences can be analysed and assessed. The presnt paper outlines a method for evaluation of the probability of ship...

  12. Collision avoidance for CTV: Requirements and capabilities

    Science.gov (United States)

    Nosek, Thomas P.

    Cargo transfer vehicle (CTV) operations near Space Station Freedom will require positive collision avoidance maneuver (CAM) capability to preclude any change of collision, even in the event of CTV failures. The requirements for CAM are discussed, and the CAM design approach and design of the Orbiting Maneuvering Vehicle (OMV) are reviewed; this design met requirements for OMV operation near the Space Station, provided a redundant collision avoidance maneuver capability. Significant portions of the OMV CAM design should be applicable to CTV. The key features of the OMV design are summarized and related to the CTV mission design to that of OMV's. CAM is a defined sequence of events executed by the CTV to place the vehicle in a safe position relative to a target such as the Space Station. CAM can be performed through software commands to the propulsion system, or through commands pre-stored in hardware. Various techniques for triggering CAM are considered, and the risks associated with CAM enable and execution in phases are considered. OMV CAM design features both hardware and software CAM capability, with analyses conducted to assess the ability to meet the collision-free requirement during all phases of the mission.

  13. Strangeness production in AA and pp collisions

    Science.gov (United States)

    Castorina, Paolo; Satz, Helmut

    2016-07-01

    Boost-invariant hadron production in high-energy collisions occurs in causally disconnected regions of finite space-time size. As a result, globally conserved quantum numbers (charge, strangeness, baryon number) are conserved locally in spatially restricted correlation clusters. Their size is determined by two time scales: the equilibration time specifying the formation of a quark-gluon plasma, and the hadronization time, specifying the onset of confinement. The expected values for these scales provide the theoretical basis for the suppression observed for strangeness production in elementary interactions ( pp , e^+e^- below LHC energies. In contrast, the space-time superposition of individual collisions in high-energy heavy-ion interactions leads to higher energy densities, resulting in much later hadronization and hence much larger hadronization volumes. This largely removes the causality constraints and results in an ideal hadronic resonance gas in full chemical equilibrium. In the present paper, we determine the collision energies needed for that; we also estimate when pp collisions reach comparable hadronization volumes and thus determine when strangeness suppression should disappear there as well.

  14. The evolution of runaway stellar collision products

    NARCIS (Netherlands)

    Glebbeek, E.; Gaburov, E.; de Mink, S.E.; Pols, O.R.; Portegies Zwart, S.F.

    2009-01-01

    In the cores of young dense star clusters, repeated stellar collisions involving the same object can occur. It has been suggested that this leads to the formation of an intermediate-mass black hole. To verify this scenario we compute the detailed evolution of the merger remnant of three sequences, t

  15. Coastal river plumes: Collisions and coalescence

    Science.gov (United States)

    Warrick, Jonathan A.; Farnsworth, Katherine L.

    2017-02-01

    Plumes of buoyant river water spread in the ocean from river mouths, and these plumes influence water quality, sediment dispersal, primary productivity, and circulation along the world's coasts. Most investigations of river plumes have focused on large rivers in a coastal region, for which the physical spreading of the plume is assumed to be independent from the influence of other buoyant plumes. Here we provide new understanding of the spreading patterns of multiple plumes interacting along simplified coastal settings by investigating: (i) the relative likelihood of plume-to-plume interactions at different settings using geophysical scaling, (ii) the diversity of plume frontal collision types and the effects of these collisions on spreading patterns of plume waters using a two-dimensional hydrodynamic model, and (iii) the fundamental differences in plume spreading patterns between coasts with single and multiple rivers using a three-dimensional hydrodynamic model. Geophysical scaling suggests that coastal margins with numerous small rivers (watershed areas 100,000 km2). When two plume fronts meet, several types of collision attributes were found, including refection, subduction and occlusion. We found that the relative differences in pre-collision plume densities and thicknesses strongly influenced the resulting collision types. The three-dimensional spreading of buoyant plumes was found to be influenced by the presence of additional rivers for all modeled scenarios, including those with and without Coriolis and wind. Combined, these results suggest that plume-to-plume interactions are common phenomena for coastal regions offshore of the world's smaller rivers and for coastal settings with multiple river mouths in close proximity, and that the spreading and fate of river waters in these settings will be strongly influenced by these interactions. We conclude that new investigations are needed to characterize how plumes interact offshore of river mouths to better

  16. Molecular Dissociation Induced by Electron Collisions

    Science.gov (United States)

    Wolf, Andreas

    2009-05-01

    Free electrons can efficiently break molecules or molecular ions in low-energy collisions by the processes of dissociative recombination or attachment. These processes make slow electrons efficient chemical agents in many environments. For dissociative recombination, in particular, studies of the underlying reaction paths and mechanisms have become possible on a uniquely elementary level in recent years both for theory and experiment. On the experimental side, collisions can be prepared at resolved collision energies down to the meV (10 Kelvin) level, increasingly gaining control also over the initial molecular quantum level, and individual events are detected and kinematically analyzed by fast-beam coincidence fragment imaging. Experiments are reported from the ion cooler ring TSR in Heidelberg. Stored beams of molecular ions cooled in their external and internal degrees of freedom are collinearly merged with intense and cold electron beams from cryogenic GaAs photocathodes, recently shown to yield fast cooling of the center-of-mass motion also for heavy and correspondingly slow molecular ion beams. To reconstruct the molecular fragmentation events multiparticle imaging can now be used systematically with collision energies set a wide range, especially aiming at specific electron capture resonances. Thus, for CF^+ it is found that the electronic state of the C fragment (^3P or ^1D) switches resonantly when the collision energy is changed by only a small fraction. As a new powerful tool, an energy-sensitive multi-strip surface-barrier detector (EMU) has been set up to measure with near-unity efficiency the masses of all fragments together with their hit positions in high-multiplicity events. Among many uses, this device allows internal molecular excitations to be derived for individual chemical channels in polyatomic fragmentation. New results will be presented in particular on the breakup of the hydronium ion (D3O^+).

  17. Collision Tumor Composed of Meningioma and Cavernoma

    Science.gov (United States)

    Weigel, Jens; Neher, Markus; Schrey, Michael; Wünsch, Peter H.; Steiner, Hans-Herbert

    2017-01-01

    A true collision tumor is a rare entity composed of two histologically distinct neoplasms coinciding in the same organ. This paper reports a unique case of cerebral collision tumor consisting of two benign components. On the first hand, meningioma which is usually a benign lesion arising from the meningothelial cell in the arachnoidal membrane. On the other, cerebral cavernoma which is a well-circumscribed, benign vascular hamartoma within the brain. To our knowledge, there is no previously documented case of cerebral collision tumor consisting of two benign components. A 56-year-old Caucasian male suffered in 2002 from an atypical meningioma WHO II° located in the left lateral ventricle. Three years after the tumor extirpation, the patient suffered from a hematoma in the fourth ventricle due to a recurrently haemorrhaged cavernoma. In 2008, a recurrence of the tumor in the left lateral ventricle was discovered. Additionally, another tumor located in the quadrigeminal lamina was detected. After surgical resection of the tumor in the left lateral ventricle, the pathological examination confirmed the diagnosis of a collision tumor consisting of components of a meningioma WHO II° and a cavernoma. Postoperatively, no adjuvant treatment was needed and no tumor recurrence is discovered up to the present. A possible explanation for the collision of those two different tumors may be migration of tumor cells mediated by the cerebrospinal fluid. After 5-years of follow-up, there is no sign of any tumor recurrence; therefore, surgical tumor removal without adjuvant therapy seems to be the treatment of choice. PMID:28061500

  18. Coastal river plumes: Collisions and coalescence

    Science.gov (United States)

    Warrick, Jonathan; Farnsworth, Katherine L

    2017-01-01

    Plumes of buoyant river water spread in the ocean from river mouths, and these plumes influence water quality, sediment dispersal, primary productivity, and circulation along the world’s coasts. Most investigations of river plumes have focused on large rivers in a coastal region, for which the physical spreading of the plume is assumed to be independent from the influence of other buoyant plumes. Here we provide new understanding of the spreading patterns of multiple plumes interacting along simplified coastal settings by investigating: (i) the relative likelihood of plume-to-plume interactions at different settings using geophysical scaling, (ii) the diversity of plume frontal collision types and the effects of these collisions on spreading patterns of plume waters using a two-dimensional hydrodynamic model, and (iii) the fundamental differences in plume spreading patterns between coasts with single and multiple rivers using a three-dimensional hydrodynamic model. Geophysical scaling suggests that coastal margins with numerous small rivers (watershed areas  100,000 km2). When two plume fronts meet, several types of collision attributes were found, including refection, subduction and occlusion. We found that the relative differences in pre-collision plume densities and thicknesses strongly influenced the resulting collision types. The three-dimensional spreading of buoyant plumes was found to be influenced by the presence of additional rivers for all modeled scenarios, including those with and without Coriolis and wind. Combined, these results suggest that plume-to-plume interactions are common phenomena for coastal regions offshore of the world’s smaller rivers and for coastal settings with multiple river mouths in close proximity, and that the spreading and fate of river waters in these settings will be strongly influenced by these interactions. We conclude that new investigations are needed to characterize how plumes interact offshore of river mouths to

  19. Review of past and present geotectonic concepts of eastern indonesia

    Science.gov (United States)

    Katili, John A.

    Ocean. Contrary to those who positioned Sulawesi close to Kalimantan in Miocene time or who separated the eastern and western arms of Sulawesi and placed them around continental Australia during its drift northwards, I maintain the view that in Miocene time Sulawesi emerged as a double island arc east of Kalimantan. For the Halmahera arc-trench system a similar origin during a younger phase of crustal movement could be advocated. The shape of the two eastern arms of Sulawesi and Halmahera can be compared with an 'arrowhead' pointing westward, with two larger slightly arcuate western arms as a 'wave front' proceeding from it. Thus Sulawesi and Halmahera were once north-south trending island arcs convex towards the Pacific with westward-dipping subduction zones. After collision with the irian Jaya plate, a reversal of polarity occurred as demonstrated by the trenches which developed northwest of Sulawesi and west of Halmahera. This controversy cannot be solved without determining the absolute ages of the eastern Sulawesi subduction complex. Marine research should also focus on the Sorong transform fault system between Sulawesi and Irian Jaya to elucidate its role in the westward displacement of the Sula-Banggai - Buton continental fragments. The nature, structure and history of the ridges in the Central Banda Sea, and their relationship to the oceanic crust of the adjacent North and South Banda Basin, should be investigated in more detail. Seram, Buru and Ambon require detailed studies to determine whether the arc-trench system predominates or whether micro-continent tectonics played the more significant role in their evolution. In the geological future, eastern Indonesia will be squashed between Australia and Asia, and the region will resemble the complex terrains now observed in the Alps and the Hercynian regions, a conclusion already drawn by the Dutch pioneers several decades ago.

  20. Eastern Canada natural gas developments

    Energy Technology Data Exchange (ETDEWEB)

    Wall, A. [Engage Energy Canada, L.P., Mississauga, ON (Canada)

    2001-07-01

    This power point presentation addressed the following topics regarding development of natural gas in eastern Canada: (1) the 18 Tcf of proven natural gas reserves at Sable Island, (2) Canadian markets benefiting from the Maritimes and Northeast Pipeline (M and NP), (3) a 20 year franchise agreement between Enbridge Gas and the government of New Brunswick, (4) the 25 year provincial franchise agreement by Sempra Atlantic Gas, and (5) Sable Island's influence on central Canada. The Sable Offshore Energy Project (SOEP) is now producing about 540,000 MMBtu/day from 6 fields. Plans for Tier 2 expansion are underway. Firm contracts for the M and NP are scheduled to transport gas from the SOEP to markets in Nova Scotia, New Brunswick, Maine and New Hampshire. Sable gas is also a potential supply for the Quebec market. Gaz Metropolitain and Enbridge have proposed to build the Cartier Pipeline from the Quebec/New Brunswick border to Quebec City. It is unlikely that Sable Island supply will directly serve the Ontario market. Canadian customers for Sable gas and M and NP service include pulp and paper companies, oil refineries, power generators and local distribution companies (LDC), with the majority of demand coming form the electric power industry. tabs., figs.

  1. Eastern Pacific Ocean Purse-seine Fishery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vessel logbook and landings data sets from U.S.A.-flagged purse-seine vessels fishing in the Eastern Pacific Ocean (EPO). These purse seiners...

  2. Palaemon pacijicus (Stimpson) in eastern Cape tidal

    African Journals Online (AJOL)

    1984-09-25

    Sep 25, 1984 ... pools, estuaries and in near -shore waters of the eastern Cape ... growth, ~ Wt is the increase in shrimp mean mass over time .... females were plotted to show changes in population structure ..... Monthly plankton tows in.

  3. Eastern Africa Social Science Research Review

    African Journals Online (AJOL)

    The Eastern Africa Social Science Research Review (EASSRR) is a bi-annual ... Dynamics of fresh produce marketing in small-scale irrigation schemes: challenges ... Analysis of media role in bridging the information gap for environmentally ...

  4. System Protection Schemes in Eastern Denmark

    DEFF Research Database (Denmark)

    Rasmussen, Joana

    The Ph.D. project investigates different aspects of voltage stability in the power system of Eastern Denmark taking into account the large amount of wind power. In the project, a simple System Protection Scheme (SPS) against voltage instability in Eastern Denmark is developed. The SPS design...... outages in the southern part of the 132-kV system introduce further stress in the power system, eventually leading to a voltage collapse. The local System Protection Scheme against voltage collapse is designed as a response-based scheme, which is dependent on local indication of reactive and active power...... for the Eastern Danish power system, such as wind farm rejection, cascading line outages and power oscillations. E.g. Nordic inter-area oscillation modes and damping were easily detected from phasor data during the outage of the 400 kV tie-line between Eastern Denmark and Sweden. It is concluded that recording...

  5. A review of Leishmaniasis in Eastern Africa

    Institute of Scientific and Technical Information of China (English)

    Peter K. Ngure; Albert Kimutai; Zipporah W. Ng'ang'a; Geoffrey Rukunga; Willy K. Tonui

    2009-01-01

    The review presents the epidemiology of leishmaniasis in the Eastern Africa region. We searched PUB MED and MEDLINE with several key words-namely,"leishmaniasis";"cutaneous"," diffuse cutaneous"," mucosal", and "visceral leishmaniasis";"kala azar" and "post kala azar dermal leishmaniasis"-for recont clinical and basic science articles related to leishmaniasis in countries in the Eastern Africa region. Poverty, wars, conflicts and migration have significantly aggravated leishmaniases in Eastern Africa. Of particular concern is the increasing incidence of Leishmania-HIV co-infection in Ethiopia where 20--40% of the persons affected by visceral leishmaniasis are HIV-co-infected. Sudan has the highest prevalence rate of post kala-azar dermal leishmaniasis(PKDL) in the world, a skin complication of visceral leishmaniasis(VL) that mainly afflicts children below age ten. In view of its spread to previously non-endemic areas and an increase in imported cases, leishmaniasis in Eastern Africa should be considered a health emergency.

  6. Properties of the Collision Efficiency of Nanoparticles in Brownian Coagulation

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-Ming; LIN Jian-Zhong; CHEN Zhong-Li

    2011-01-01

    The collision efficiency of nanoparticles with diameters from 100 nm to 750nm in the Brownian coagulation is studied by building and solving numerically the equations of particle collision in the presence of the van der Waals force, the elastic deformation force, the Stokes resistance, the lubrication force and the electrostatic force. The results show that the collision efficiency decreases overall with the increasing particle diameter. It is found that there exists an abrupt increase in the collision efficiency when the particle diameter is equals to 550 nm. Finally a new expression for the collision efficiency is presented.

  7. Studies of multiplicity in relativistic heavy-ion collisions

    CERN Document Server

    Back, B B; Alexa, C; Arnaldi, R; Atayan, M; Baglin, C; Baldit, A; Bedjidian, M; Beolè, S; Boldea, V; Bordalo,a, P; Borenstein, S R; Borges, G; Bussière, A; Capelli, L; Castanier, C; Castor, J I; Chaurand, B; Cheynis, B; Chiavassa, E; Cical, C; Claudino, T; Comets, M P; Constantinescu, S; Cortese, P; Cruz, J; De Falco, A; De Marco, N; Dellacasa, G; Devaux, A; Dita, S; Drapier, O; Espagnon, B; Fargeix, J; Force, P; Gallio, M; Gavrilov, Yu K; Gerschel, C; Giubellino,c, P; Golubeva, M B; Gonin, M; Grigorian, A A; Grigorian, S; Grossiord, J Y; Guber, F F; Guichard, A; Gulkanian, H R; Hokobyan, R; Haroutunian, R; Idzik, M; Jouan, D; Karavitcheva, T L; Kluberg, L; Kurepin, A B; Le Bornec, Y; Lourenço, C; Macciotta, P; MacCormick, M; Marzari-Chiesa, A; Masera, M; Masoni, A; Monteno, M; Musso, A; Petiau, P; Piccotti, A; Pizzi, J R; Prado da Silva, W L; Prino, F; Puddu, G; Quintans, C; Ramello, L; Ramos,a, S; Rato-Mendes, P; Riccati, L; Romana, A; Santos, H; Saturnini, P; Scalas, E; Scomparin, E; Serci, S; Shahoyan, R; Sigaudo, F; Sitta, M; Sonderegger, P; Tarrago, X; Topilskaya, N S; Usai, G L; Vercellin, E; Villatte, L; Willis, N; Wu, T

    2005-01-01

    In this talk I'll review the present status of charged particle multiplicity measurements from heavy-ion collisions. The characteristic features of multiplicity distributions obtained in Au+Au collisions will be discussed in terms of collision centrality and energy and compared to those of p+p collisions. Multiplicity measurements of d+Au collisions at 200 GeV nucleon-nucleon center-of-mass energy will also be discussed. The results will be compared to various theoretical models and simple scaling properties of the data will be identified.

  8. Total Probability of Collision as a Metric for Finite Conjunction Assessment and Collision Risk Management

    Science.gov (United States)

    Frigm, R.; Johnson, L.

    The Probability of Collision (Pc) has become a universal metric and statement of on-orbit collision risk. Although several flavors of the computation exist and are well-documented in the literature, the basic calculation requires the same input: estimates for the position, position uncertainty, and sizes of the two objects involved. The Pc is used operationally to make decisions on whether a given conjunction poses significant collision risk to the primary object (or space asset of concern). It is also used to determine necessity and degree of mitigative action (typically in the form of an orbital maneuver) to be performed. The predicted post-maneuver Pc also informs the maneuver planning process into regarding the timing, direction, and magnitude of the maneuver needed to mitigate the collision risk. Although the data sources, techniques, decision calculus, and workflows vary for different agencies and organizations, they all have a common thread. The standard conjunction assessment and collision risk concept of operations (CONOPS) predicts conjunctions, assesses the collision risk (typically, via the Pc), and plans and executes avoidance activities for conjunctions as a discrete events. As the space debris environment continues to increase and improvements are made to remote sensing capabilities and sensitivities to detect, track, and predict smaller debris objects, the number of conjunctions will in turn continue to increase. The expected order-of-magnitude increase in the number of predicted conjunctions will challenge the paradigm of treating each conjunction as a discrete event. The challenge will not be limited to workload issues, such as manpower and computing performance, but also the ability for satellite owner/operators to successfully execute their mission while also managing on-orbit collision risk. Executing a propulsive maneuver occasionally can easily be absorbed into the mission planning and operations tempo; whereas, continuously planning evasive

  9. Paleozoic accretionary orogenesis in the eastern Beishan orogen: constraints from zircon U-Pb and 40Ar/39Ar geochronology

    Science.gov (United States)

    Ao, Songjian; Xiao, Wenjiao; Windley, Brian; Mao, Qigui

    2016-04-01

    The continental growth mechanism of the Altaids in Central Asia is still in controversy between models of continuous subduction-accretion versus punctuated accretion by closure of multiple oceanic basins. The Beishan orogenic belt, located in the southern Altaids, is a natural laboratory to address this controversy. Key questions that are heavily debated are: the closure time and subduction polarity of former oceans, the emplacement time of ophiolites, and the styles of accretion and collision. This paper reports new structural data, zircon ages and Ar-Ar dates from the eastern Beishan Orogen that provide information on the accretion process and tectonic affiliation of various terranes. Our geochronological and structural results show that the younging direction of accretion was northwards and the subduction zone dipped southwards under the northern margin of the Shuangyingshan micro-continent. This long-lived and continuous accretion process formed the Hanshan accretionary prism. Our field investigations show that the emplacement of the Xiaohuangshan ophiolite was controlled by oceanic crust subduction beneath the forearc accretionary prism of the Shuangyingshan-Mazongshan composite arc to the south. Moreover, we address the age and terrane affiliation of lithologies in the eastern Beishan orogen through detrital zircon geochronology of meta-sedimentary rocks. We provide new information on the ages, subduction polarities, and affiliation of constituent structural units, as well as a new model of tectonic evolution of the eastern Beishan orogen. The accretionary processes and crustal growth of Central Asia were the result of multiple sequences of accretion and collision of manifold terranes. Reference: Ao, S.J., Xiao, W., Windley, B.F., Mao, Q., Han, C., Zhang, J.e., Yang, L., Geng, J., Paleozoic accretionary orogenesis in the eastern Beishan orogen: Constraints from zircon U-Pb and 40Ar/39Ar geochronology. Gondwana Research, doi: http://dx.doi.org/10.1016/j

  10. Trace elements in coals of eastern Donbas

    Energy Technology Data Exchange (ETDEWEB)

    Taranushich, F.F. [All Russian Research & Geological Prospecting Institute for Coal Deposits, Rostov Na Donu (Russian Federation)

    2003-02-01

    Peculiarities of trace element (TE) distribution in coals of the eastern Donets Basin (Donbas) are discussed. The correlation of TE distribution with specific features of the geological setting of the region can testify to the hydrothermal introduction of trace elements or their redistribution in fluid-active zones. The geochemical regionalization of eastern Donbas is based on TE distribution. Strontium-gold-base metal, tungsten, and selenium geochemical belts and a rare metal geochemical block are outlined.

  11. Midwifery education in Central-Eastern Europe.

    Science.gov (United States)

    Mivšek, Polona; Baškova, Martina; Wilhelmova, Radka

    2016-02-01

    Problems in midwifery in many Central-Eastern European countries are very similar; it is possible to speak about the evolving Central-Eastern model of midwifery care. The educational models of this region have a relatively strong theoretical part; however, there is an insufficient practical dimension. Theoretical part of midwifery education in the universities is relatively autonomous and is slowly changing the professional identity of graduates.

  12. How Tiny Collisions Shape Mercury

    Science.gov (United States)

    Kohler, Susanna

    2017-07-01

    If space rocks are unpleasant to encounter, space dust isnt much better. Mercurys cratered surface tells of billions of years of meteoroid impacts but its thin atmosphere is what reveals its collisional history with smaller impactors. Now new research is providing a better understanding of what were seeing.Micrometeoroids Ho!The inner solar system is bombarded by micrometeoroids, tiny particles of dust (on the scale of a tenth of a millimeter) emitted by asteroids and comets as they make their closest approach to the Sun. This dust doesnt penetrateEarths layers of atmosphere, but the innermost planet of our solar system, Mercury, doesnt have this convenient cushioning.Just as Mercury is affected by the impacts of large meteoroids, its also shaped by the many smaller-scale impacts it experiences. These tiny collisions are thought to vaporize atoms and molecules from the planets surface, which quickly dissociate. This process adds metals to Mercurys exosphere, the planets extremely tenuous atmosphere.Modeling PopulationsDistribution of the directions from which meteoroids originate before impacting Mercurys surface, as averaged over its entire orbit. Local time of 12 hr corresponds to the Sun-facing side. A significant asymmetry is seen between the dawn (6 hrs) and dusk (18 hrs) rates. [Pokorn et al. 2017]The metal distribution in the exosphere provides a way for us to measure the effect of micrometeoroid impacts on Mercury but this only works if we have accurate models of the process. A team of scientists led by Petr Pokorn (The Catholic University of America and NASA Goddard SFC) has now worked to improve our picture of micrometeoroid impact vaporization on Mercury.Pokorn and collaborators argue that two meteoroid populations Jupiter-family comets (short-period) and Halley-type comets (long-period) contribute the dust for the majority of micrometeoroid impacts on Mercury. The authors model the dynamics and evolution of these two populations, reproducing the

  13. Permo-Triassic evolution of Gondwanan eastern Indonesia, and the final Mesozoic separation of SE Asia from Australia

    Science.gov (United States)

    Charlton, T. R.

    2001-08-01

    Continental fragments with Australian/Gondwanan stratigraphic affinities are widely distributed throughout the eastern Indonesia collision complex. Despite their structural isolation from one another as a consequence of Tertiary orogenesis, these fragments show a remarkably uniform pattern of Permo-Triassic tectonostratigraphy, ranging from a granitoid belt in the north, through a continental platform, to an intracontinental rift system in the south. Within the rift system complementary upper and lower plate rifted margins can be recognised in the northern and southern Banda Arcs, respectively. The northern granitoid belt was initiated in the mid-Carboniferous, whilst the intracontinental rift system began to develop in latest Carboniferous-earliest Permian times. Extension in the northern rift margin ceased in the mid-Carnian (early Late Triassic), contemporaneous with a marked decline in igneous activity in the granitoid belt to the north. The Sibumasu Terrane of mainland SE Asia probably originated on the Gondwanaland continental margin, adjacent to reconstructed eastern Indonesia, but rifted away during the Early Permian. Previous interpretations have seen this rifting as marking the final separation between Gondwanaland and continental terranes now forming SE Asia. Alternatively, it is suggested here that Gondwanan eastern Indonesia acted as an indirect continental connection between Sibumasu/Indochina and Australia during the Permian and Triassic. This continental isthmus permitted continuing limited floral and faunal interchange between Gondwanaland and SE Asia until a final separation in the Late Triassic. The mid-Carnian structural event in eastern Indonesia is interpreted as related to this separation.

  14. Hybrid Collision Detection Algorithm based on Image Space

    Directory of Open Access Journals (Sweden)

    XueLi Shen

    2013-07-01

    Full Text Available Collision detection is an important application in the field of virtual reality, and efficiently completing collision detection has become the research focus. For the poorly real-time defect of collision detection, this paper has presented an algorithm based on the hybrid collision detection, detecting the potential collision object sets quickly with the mixed bounding volume hierarchy tree, and then using the streaming pattern collision detection algorithm to make an accurate detection. With the above methods, it can achieve the purpose of balancing load of the CPU and GPU and speeding up the detection rate. The experimental results show that compared with the classic Rapid algorithm, this algorithm can effectively improve the efficiency of collision detection.

  15. Multiple Cosmic Collisions and the Microwave Background Power Spectrum

    CERN Document Server

    Kozaczuk, Jonathan

    2012-01-01

    Collisions between cosmic bubbles of different vacua are a generic feature of false vacuum eternal inflation scenarios. While previous studies have focused on the consequences of a single collision event in an observer's past, we begin here an investigation of the more general scenario allowing for many "mild" collisions intersecting our past light cone (and one another). We discuss the general features of multiple collision scenarios and consider their impact on the cosmic microwave background (CMB) temperature power spectrum, treating the collisions perturbatively. In a large class of models, one can approximate a multiple collision scenario as a superposition of individual collision events governed by nearly isotropic and scale-invariant distributions, most appearing to take up less than half of the sky. In this case, the shape of the expected CMB temperature spectrum maintains statistical isotropy and typically features a dramatic increase in power in the low multipoles relative to that of the best-fit $\\...

  16. Collision, rotation, and the initiation of subduction in the evolution of Sulawesi, Indonesia

    Science.gov (United States)

    Silver, Eli A.; McCaffrey, Robert; Smith, Randall B.

    1983-11-01

    The island of Sulawesi, Indonesia, has been shaped and deformed as a result of collision with the Sula platform, a sliver of continental material from the northern margin of Australia-New Guinea. The collision has resulted in rotation of the north volcanic arm of Sulawesi and the development of the accretionary wedge of the North Sulawesi trench. The North Sulawesi trench changes laterally from a zone of no active deformation in the eastern part to a wide accretionary wedge in the west. Early stages of thrusting produce a steep frontal slope (8°-16°), indicative of relatively high basal shear stress, whereas the more advanced (western) zone of thrusting produces a gentle (2°) slope, consistent with low basal shear stress. Reported paleomagnetic data suggest post late Eocene counter-clockwise rotation of the North Arm, and the offshore geophysics are explained by a pivot of the North Arm with respect to the Celebes basin about the eastern end of the arc. Convergence between the north Banda basin and Southeast Sulawesi is documented by the presence of the Tolo thrust. Its outcrop is strongly arcuate and its accretionary wedge varies in width from a minimum of a few kilometers at each end to a maximum of 30-40 km in the central part. The northern end transforms to the leftlateral Matano fault, with a reported offset of 20 km. The southern end of the thrust projects toward the deformed rocks of Buton, but the structural relations there are not clear. The Matano fault zone appears to connect westward with the Palu fault, which forms the western transform of the North Sulawesi trench. The Palu-Matano fault system acts as a trench-trench transform between the North Sulawesi trench and the Tolo thrust, and this system is described by the same rotation pole as that for the Sulawesi North Arm.

  17. Peralkaline volcanism in a continental collisional setting: Mount Nemrut volcano, Eastern Anatolia

    Science.gov (United States)

    Çubukçu, H. E.; Ulusoy, I.; Aydar, E.; Sen, E.; Ersoy, O.; Gourgaud, A.

    2012-04-01

    Quaternary Mount Nemrut is an active volcano in the Eastern Anatolia which culminates at 2948 m and having an elliptic summit caldera with 8.5 x 7 km diameter. The volcano is situated on the east of the deformed and dissected remnant of the Muş-Van ramp basin located at the northern foot of the Bitlis-Zagros suture zone. The suture zone is the southern margin of the continental collision between Arabian and Anatolian plates. The continental collision along the Bitlis-Zagros suture zone commenced in the Middle Miocene following the closure of the southern segment of Neo-Tethys ocean and the subduction of northern margin of Arabian plate beneath Anatolian plate. Upon the collision and the uplift of the region, widespread volcanism, which exhibits varying eruption styles and geochemical characteristics, affected most of the Eastern Anatolia. The intracontinental convergence and N - S directed compressional - contractional tectonic regime remained till the end of Late Miocene. However, compressional - extensional regime became dominant in the Early-Late Pliocene. Following the slab break off, asthenosphere beneath the Arabian Foreland probably have migrated towards the slab window, which was opened during the detachment, and invaded the mantle wedge beneath East Anatolian Collision zone. Volcanism is still active in the region, represented by major Quaternary volcanic centers. The magmatic characteristics of Nemrut volcano is appealingly distinct compared to the other Quaternary volcanic centers in the region. The overall geochemical and mineralogical affinity of Nemrut volcanism exhibits strong similarities with the well-known sites of continental intra-plate extension. The volcano has distinguishing features of a typical silica oversaturated peralkaline (molecular ratio (Na + K / Al)>1) suite: (a) The volcanic products vary from transitional olivine basalt to peralkaline rhyolite (abundant comendite and scarce pantellerite) (b) Predominance by erupted volume of

  18. Morphological characteristics in the area off eastern Taiwan Island and their tectonic implications

    Institute of Scientific and Technical Information of China (English)

    LIUBaohua; ZHENGYanpeng; WUJinlong; HANGuozhong; ZHANGDeyu

    2004-01-01

    On the basis of bathymetric data and other geological and geophysical data obtained during the first survey conducted by Chinese Mainland in the area off eastern Taiwan Island from May to June in 2000, the morphological features of the region, the tectonic control to the seafloor topography and their tectonic implication are studied and discussed. The results have revealed that both the slope zone of the Ryukyu arc and the Ryukyu Trench present a typical morphotectonic characteristics controlled by the trench-arc system in the West Pacific Ocean. At the slope of eastern Taiwan Island the isobathic lines parallel to the coastline and distribute densely in nearly N-S direction and the slope gradient of topography is large. Such a unique feature is attributed to the collision of the Luzon arc and Eurasia continent. In the Huatung Basin, turbidity fans and submarine canyons are well developed, the formations of which are mainly related to the steep topography of the slope of the Luzon arc and the abundant supply of sediments. These submarine canyons are controlled by basement highs and strike-slip faults. On eastern side and western side of the Gagua Ridge, both the water depth and morphological features are different, but the basement of Gagua Ridge belongs to the Huatung Basin. The eastern side of the Gagua Ridge (123°12' E) corresponds to the boundary of two plates with different ages. In the West Philippine Basin, linear ridges and troughs in a NW trending are identified, which are dissected by a NE trending transform fault. According to the seafloor topography features, the direction of the transform fault and the magnetic anomaly lineations, the seafloor of this region was formed during 60-45 Ma B.P when the West Philippine Basin was spreading along NE-SW relative to the present orientation.

  19. Transition of the Taiwan-Ryukyu collision-subduction process as revealed by ocean-bottom seismometer observations

    Science.gov (United States)

    Chin, Shao-Jinn; Lin, Jing-Yi; Chen, Yen-Fu; Wu, Wen-Nan; Liang, Chin-Wei

    2016-10-01

    Located at the arc-continental collision region between the Eurasian (EP) and Philippine Sea Plates (PSP), Taiwan is usually considered to have a complex tectonic environment, particularly along the eastern coast of the island. To gain a better understanding of the geological evolution of the east Taiwan area, the data from 8 Ocean Bottom Seismometers (OBS) acquired during the Across Taiwan Strait Explosion Experiment in 2012 and 14 inland seismic stations were used to determine a more detailed and accurate distribution of marine earthquakes. Based on the 333 relocated earthquakes and available geophysical data, we suggest two main tectonic boundaries for eastern Taiwan. South of 23.25°N, the homogeneous distribution of earthquakes in the crustal portion for both the inland and offshore areas suggests an ongoing collisional process. North of this location, between approximately 23.25°N and 23.8°N, the abrupt increasing of seismicity depth infers that the underthrusted arc/fore-arc material is deforming due to the collisional compression at depth. In this segment, the subsidence of the arc/fore-arc area determines the transition from collision to subduction. North of 23.8°N, the northwestern dipping PSP is well illustrated by the seismicity both onshore and offshore, indicating a dominant subduction process.

  20. Exotic hadrons from heavy ion collisions

    Science.gov (United States)

    Cho, Sungtae; Hyodo, Tetsuo; Jido, Daisuke; Ko, Che Ming; Lee, Su Houng; Maeda, Saori; Miyahara, Kenta; Morita, Kenji; Nielsen, Marina; Ohnishi, Akira; Sekihara, Takayasu; Song, Taesoo; Yasui, Shigehiro; Yazaki, Koichi

    2017-07-01

    High energy heavy ion collisions are excellent ways for producing heavy hadrons and composite particles, including the light (anti)nuclei. With upgraded detectors at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC), it has become possible to measure hadrons beyond their ground states. Therefore, heavy ion collisions provide a new method for studying exotic hadrons that are either molecular states made of various hadrons or compact system consisting of multiquarks. Because their structures are related to the fundamental properties of Quantum Chromodynamics (QCD), studying exotic hadrons is currently one of the most active areas of research in hadron physics. Experiments carried out at various accelerator facilities have indicated that some exotic hadrons may have already been produced. The present review is a summary of the current understanding of a selected set of exotic particle candidates that can be potentially measured in heavy ion collisions. It also includes discussions on the production of resonances, exotics and hadronic molecular states in these collisions based on the coalescence model and the statistical model. A more detailed discussion is given on the results from these models, leading to the conclusion that the yield of a hadron that is a compact multiquark state is typically an order of magnitude smaller than if it is an excited hadronic state with normal quark numbers or a loosely bound hadronic molecule. Attention is also given to some of the proposed heavy exotic hadrons that could be produced with sufficient abundance in heavy ion collisions because of the significant numbers of charm and bottom quarks that are produced at RHIC and even larger numbers at LHC, making it possible to study them in these experiments. Further included in the discussion are the general formalism for the coalescence model that involves resonance particles and its implication on the present estimated yield for resonance production. Finally

  1. Eastern slopes grizzly bear project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-01-01

    The cumulative effects of human activities on the grizzly bears in the central Canadian Rockies are not well known. As a result, a project was initiated in 1994 to address the urgent requirement for accurate scientific information on the habitat and populations of grizzly bears in the area of the Banff National Park and Kananaskis Country. This area is probably the most heavily used and developed area where the grizzly still survives. The information gathered throughout the course of this study will be used to better protect and manage the bears and other sensitive carnivores in the region. Using telemetry, researchers are monitoring 25 grizzly bears which were radio-collared in a 22,000 square-kilometer area in the upper Bow Valley drainage of the eastern Alberta slopes. The researchers involved in the project are working with representatives from Husky Oil and Talisman Energy on the sound development of the Moose Mountain oil and gas field without adversely affecting the grizzly bear population. Information collected over seven years indicated that the grizzly bears have few and infrequent offspring. Using the information gathered so far, the location of the Moose Mountain to Jumping Pound pipeline was carefully selected, since the bears recover very slowly from high mortality, and also considering that the food and cover had already been compromised by the high number of roads, trails and other human activities in the area. The status of the population and habitat of the grizzly bear will be assessed upon the conclusion of the field research phase in 2001. Models will be updated using the data obtained during eight years and will assist in the understanding of complex variables that affect grizzly bears.

  2. Kinematics of the western Caribbean: Collision of the Cocos Ridge and upper plate deformation

    Science.gov (United States)

    Kobayashi, Daisuke; LaFemina, Peter; Geirsson, Halldór; Chichaco, Eric; Abrego, Antonio A.; Mora, Hector; Camacho, Eduardo

    2014-05-01

    Subduction of the Cocos plate and collision of the Cocos Ridge have profound effects on the kinematics of the western Caribbean, including crustal shortening, segmentation of the overriding plate, and tectonic escape of the Central American fore arc (CAFA). Tectonic models of the Panama Region (PR) have ranged from a rigid block to a deforming plate boundary zone. Recent expansion of GPS networks in Panama, Costa Rica, and Colombia makes it possible to constrain the kinematics of the PR. We present an improved kinematic block model for the western Caribbean, using this improved GPS network to test a suite of tectonic models describing the kinematics of this region. The best fit model predicts an Euler vector for the counterclockwise rotation of the CAFA relative to the Caribbean plate at 89.10°W, 7.74°N, 1.193° Ma-1, which is expressed as northwest-directed relative block rates of 11.3 ± 1.0-16.5 ± 1.1 mm a-1 from northern Costa Rica to Guatemala. This model also predicts high coupling along the Nicoya and Osa segments of the Middle American subduction zone. Our models demonstrate that the PR acts as a single tectonic block, the Panama block, with a predicted Euler vector of 107.65°W, 26.50°N, 0.133° Ma-1. This rotation manifests as northeast migration of the Panama block at rates of 6.9 ± 4.0-7.8 ± 4.8 mm a-1 from southern Costa Rica to eastern Panama. We interpret this motion as tectonic escape from Cocos Ridge collision, redirected by collision with the North Andes block, which migrates to the northwest at 12.2 ± 1.2 mm a-1.

  3. Long-range consequences of interplanetary collisions

    Science.gov (United States)

    Sagan, Carl; Ostro, Steven J.

    1994-01-01

    As Comet Shoemaker-Levy 9 races toward its mid-July collision with the planet Jupiter, considerable public attention is focused on catastrophic impacts with the Earth -- in the past and in the future. In recent years calls have been made to develop technologies that could deflect any asteroid or comet on a collision course. Careful consideration must be given to the nature and time scale of the risk and to the cost-effectiveness and possible problems in the suggested solutions. Risk assessment, threat removal, and resources misuse are examined. The greatest concern is to have a poorly informed public -- exerting pressure for means to mitigate even non-existent threats. The only foreseeable solution is a combination of accurate orbit estimation, realistic threat assessment, and effective public education.

  4. Electron collisions with coherently prepared atomic targets

    Energy Technology Data Exchange (ETDEWEB)

    Trajmar, S.; Kanik, I.; LeClair, L.R.; Khakoo, M.S. [California Inst. of Tech., Pasadena, CA (United States). Jet Propulsion Lab.; Bray, I.; Fursa, D. [Flinders Univ. of South Australia, Adelaide (Australia). Electronics Structure of Materials Centre; Csanak, G. [Los Alamos National Lab., NM (United States)

    1998-02-01

    The subject of electron scattering by laser-excited atoms is briefly reviewed. To demonstrate some aspects of these electron collision processes, the authors describe the procedures and the results of a joint experimental and theoretical study concerning elastic scattering by coherently excited {sup 138}Ba (...6s6p {sup 1}P{sub 1}) atoms. Examples of experimental and theoretical collision parameters and magnetic sublevel differential cross sections for elastic scattering are given and compared. The convergent close coupling calculations (with the neglect of spin-orbit interaction) are in good agreement with experiment at 20 eV impact energy and 10, 15 and 20{degree} scattering angles and can be expected to yield reliable integral magnetic sublevel and alignment creation cross sections. The role of these quantities in plasma polarization spectroscopy is pointed out.

  5. Transplanckian Collisions at the LHC and Beyond

    CERN Document Server

    Giudice, Gian Francesco; Wells, J D; Giudice, Gian F.; Rattazzi, Riccardo; Wells, James D.

    2002-01-01

    Elastic collisions in the transplanckian region, where the center-of-mass energy is much larger than the fundamental gravity mass scale, can be described by linearized general relativity and known quantum-mechanical effects as long as the momentum transfer of the process is sufficiently small. For larger momentum transfer, non-linear gravitational effects become important and, although a computation is lacking, black-hole formation is expected to dominate the dynamics. We discuss how elastic transplanckian collisions can be used at high-energy colliders to study, in a quantitative and model-independent way, theories in which gravity propagates in flat extra dimensions. At LHC energies, however, incalculable quantum-gravity contributions may significantly affect the experimental signal.

  6. Axion bremsstrahlung from collisions of global strings

    CERN Document Server

    Galtsov, D V; Kerner, R

    2003-01-01

    We calculate axion radiation emitted in the collision of two straight global strings. The strings are supposed to be in the unexcited ground state, to be inclined with respect to each other, and to move in parallel planes. Radiation arises when the point of minimal separation between the strings moves faster than light. This effect exhibits a typical Cerenkov nature. Surprisingly, it allows an alternative interpretation as bremsstrahlung under a collision of point charges in 2+1 electrodynamics. This can be demonstrated by suitable world-sheet reparameterizations and dimensional reduction. Cosmological estimates show that our mechanism generates axion production comparable with that from the oscillating string loops and may lead to further restrictions on the axion window.

  7. New Post-Collision Line Design

    CERN Document Server

    Gatignon, Lau

    2014-01-01

    The 1.5 TeV Compact Linear Collider (CLIC) beams, with a total power of 14 MW per beam, are disrupted at the interaction point due to the very strong beam-beam effect. As a result, some 3.5 MW reach each main dump in form of beamstrahlung photons. About 0.5 MW of e+e- pairs with a very broad energy spectrum need to be disposed of along the post-collision line while separating the various beams by charge for beam diagnostics purposes. The Post-collision line has been optimised in order to reduce radiation damage to magnets, the number of magnets required and the stray fields to the incoming beam line.

  8. Inelastic collisions of excited lithium molecules

    Science.gov (United States)

    Rosenberry, Mark; Marhatta, Ramesh; Stewart, Brian

    2010-03-01

    Energy transfer and reactions during molecular collisions are fundamental processes in astronomy and chemistry. The H2 + H system has been well studied, and theoretical calculations are now becoming feasible for an excited lithium dimer colliding with a ground state lithium atom, increasing interest in corresponding experimental measurements. Our laboratory observes laser-induced fluorescence spectra from lithium vapor in a heat pipe oven. Our recent switch from a modest diode laser to a pulsed dye laser gives us new access to a variety of highly excited molecular states. Here we report our progress in measuring absolute level-to-level rate constants and collision-induced dissociation for molecular states of this system.

  9. High energy particle collisions near black holes

    Directory of Open Access Journals (Sweden)

    Zaslavskii O. B.

    2016-01-01

    Full Text Available If two geodesic particles collide near a rotating black hole, their energy in the centre of mass frame Ec.m. can become unbound under certain conditions (the so-called BSW effect. The special role is played here by so-called critical geodesics when one of particles has fine-tuned energy and angular momentum. The nature of geodesics reveals itself also in fate of the debris after collisions. One of particles moving to a remote observer is necessarily near-critical. We discuss, when such a collision can give rise not only unboud Ec.m. but also unbound Killing energy E (so-called super-Penrose process.

  10. Path Integral Approach to Atomic Collisions

    Science.gov (United States)

    Harris, Allison

    2016-09-01

    The Path Integral technique is an alternative formulation of quantum mechanics that is based on a Lagrangian approach. In its exact form, it is completely equivalent to the Hamiltonian-based Schrödinger equation approach. Developed by Feynman in the 1940's, following inspiration from Dirac, the path integral approach has been widely used in high energy physics, quantum field theory, and statistical mechanics. However, only in limited cases has the path integral approach been applied to quantum mechanical few-body scattering. We present a theoretical and computational development of the path integral method for use in the study of atomic collisions. Preliminary results are presented for some simple systems. Ultimately, this approach will be applied to few-body ion-atom collisions. Work supported by NSF grant PHY-1505217.

  11. The CLIC Post-Collision Line

    CERN Document Server

    Gschwendtner, E; Elsener, K; Sailer, A; Uythoven, J; Appleby, R B; Salt, M; Ferrari, A; Ziemann, V

    2010-01-01

    The 1.5 TeV CLIC beams, with a total power of 14 MW per beam, are disrupted at the interaction point due to the very strong beam-beam effect. As a result, some 3.5 MW reach the main dump in form of beamstrahlung photons. About 0.5 MW of e+e- pairs with a very broad energy spectrum need to be disposed of along the post-collision line. The conceptual design of this beam line will be presented. Emphasis will be on the optimization studies of the CLIC post-collision line design with respect to the energy deposition in windows, dumps and absorbers, on the design of the luminosity monitoring for a fast feedback to the beam steering and on the background conditions for the luminosity monitoring equipment.

  12. CLIC Post-Collision Line Luminosity Monitoring

    CERN Document Server

    Appleby, R B; Deacon, L; Geschwendtner, E

    2011-01-01

    The CLIC post collision line is designed to transport the un-collided beams and the products of the collided beams with a total power of 14MW to the main beam dump. Full Monte Carlo simulation has been done for the description of the CLIC luminosity monitoring in the post collision line. One method of the luminosity diagnostic is based on the detection of high energy muons produced by beamstrahlung photons in the main beam dump. The disrupted beam and the beamstrahlung photons produce at the order of 106 muons per bunch crossing per cm2, with energies higher than 10 GeV. Threshold Cherenkov counters are considered after the beam dump for the detection of these high energy muons. Another method for luminosity monitoring is presented using the direct detection of the beamstrahlung photons.

  13. Positronium collisions with rare-gas atoms

    CERN Document Server

    Gribakin, G F; Wilde, R S; Fabrikant, I I

    2015-01-01

    We calculate elastic scattering of positronium (Ps) by the Xe atom using the recently developed pseudopotential method [Fabrikant I I and Gribakin G F 2014 Phys. Rev. A 90 052717] and review general features of Ps scattering from heavier rare-gas atoms: Ar, Kr and Xe. The total scattering cross section is dominated by two contributions: elastic scattering and Ps ionization (break-up). To calculate the Ps ionization cross sections we use the binary-encounter method for Ps collisions with an atomic target. Our results for the ionization cross section agree well with previous calculations carried out in the impulse approximation. Our total Ps-Xe cross section, when plotted as a function of the projectile velocity, exhibits similarity with the electron-Xe cross section for the collision velocities higher than 0.8 a.u., and agrees very well with the measurements at Ps velocities above 0.5 a.u.

  14. Holography, Hydrodynamization and Heavy-Ion Collisions

    CERN Document Server

    Heller, Michal P

    2016-01-01

    In the course of the past several years holography has emerged as an ab initio tool in exploring strongly-time-dependent phenomena in gauge theories. These lecture notes overview recent developments in this area driven by phenomenological questions concerning applicability of hydrodynamics under extreme conditions occurring in ultrarelativistic heavy-ion collisions at RHIC and LHC. The topics include equilibration time scales, holographic collisions and hydrodynamization from the point of view of the asymptotic character of the hydrodynamic gradient expansion. The emphasis is put on concepts rather than calculational techniques and particular attention is devoted to present these developments in the context of the most recent advances and some of the open problems.

  15. Strangeness Production in AA and pp Collisions

    CERN Document Server

    Satz, P Castorina ad H

    2016-01-01

    Boost-invariant hadron production in high energy collisions occurs in causally disconnected regions of finite space-time size. As a result, globally conserved quantum numbers (charge, strangeness, baryon number) are conserved locally in spatially restricted correlation clusters. Their size is determined by two time scales: the equilibration time specifying the formation of a quark-gluon plasma, and the hadronization time, specifying the onset of confinement. The expected values for these scales provide the theoretical basis for the suppression observed for strangeness production in elementary interactions ($pp$, $e^+e^-$) below LHC energies. In contrast, the space-time superposition of individual collisions in high energy heavy ion interactions leads to higher energy densities, resulting in much later hadronization and hence much larger hadronization volumes. This largely removes the causality constraints and results in an ideal hadronic resonance gas in full chemical equilibrium. In the present paper, we det...

  16. Theory of Electron-Ion Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, Donald C

    2009-10-02

    Collisions of electrons with atoms and ions play a crucial role in the modeling and diagnostics of fusion plasmas. In the edge and divertor regions of magnetically confined plasmas, data for the collisions of electrons with neutral atoms and low charge-state ions are of particular importance, while in the inner region, data on highly ionized species are needed. Since experimental measurements for these collisional processes remain very limited, data for such processes depend primarily on the results of theoretical calculations. Over the period of the present grant (January 2006 - August 2009), we have made additional improvements in our parallel scattering programs, generated data of direct fusion interest and made these data available on The Controlled Fusion Atomic Data Center Web site at Oak Ridge National Laboratory. In addition, we have employed these data to do collsional-radiative modeling studies in support of a variety of experiments with magnetically confined fusion plasmas.

  17. Crash and burn? Vehicle, collision, and driver factors that influence motor vehicle collision fires.

    Science.gov (United States)

    Bunn, T L; Slavova, S; Robertson, M

    2012-07-01

    A retrospective population-based case-control study was performed to determine the association between vehicle fires, and vehicle, collision, and driver factors on highways with a posted speed limit of at least 55mph. Data were obtained from the Kentucky Collision Report Analysis for Safer Highways (CRASH) electronic files for 2000-2009 from the Kentucky State Police Records Sections. The results from the final multiple logistic regression show that large trucks were at a higher risk for a collision involving a fire than passenger vehicles and pickup trucks. When controlling for all other variables in the model, vehicles 6 years old and older, driving straight down the highway, and single vehicle collisions were also identified as factors that increase the risk of motor vehicle collision fires on roadways with a posted speed limit of ≥55mph. Of the 2096 vehicles that caught fire, there were 632 (30%) non-fatally injured drivers and 224 (11%) fatally injured drivers. The results of this study have the potential to inform public health messages directed to the transportation industry, particularly semi truck drivers, in regard to fire risk.

  18. Evolution of stellar collision products in open clusters. II. A grid of low-mass collisions

    CERN Document Server

    Glebbeek, E

    2008-01-01

    In a companion paper we studied the detailed evolution of stellar collision products that occurred in an $N$-body simulation of the old open cluster M67 and compared our detailed models to simple prescriptions. In this paper we extend this work by studying the evolution of the collision products in open clusters as a function of mass and age of the progenitor stars. We calculated a grid of head-on collisions covering the section of parameter space relevant for collisions in open clusters. We create detailed models of the merger remnants using an entropy-sorting algorithm and follow their subsequent evolution during the initial contraction phase, through the main sequence and up to the giant branch with our detailed stellar evolution code. We compare the location of our models in a colour-magnitude diagram to the observed blue straggler population of the old open clusters M67 and NGC 188 and find that they cover the observed blue straggler region of both clusters. For M67, collisions need to have taken place r...

  19. Three-body collision contributions to recombination and collision-induced dissociation. 1: Cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Pack, R.T.; Walker, R.B.; Kendrick, B.K.

    1998-04-10

    Atomic and molecular recombination and collision-induced dissociation (CID) reactions comprise two of the most fundamental types of chemical reactions. They are important in all gas phase chemistry; for example, about half of the 196 reactions identified as important in combustion chemistry are recombination or CID reactions. Many of the current chemical kinetics textbooks and kinetics papers treat atomic and molecular recombination and CID as occurring only via sequences of two-body collisions. Actually, there is considerable evidence from experiment and classical trajectory calculations for contributions by true three-body collisions to the recombination of atomic and diatomic radicals, and that evidence is reviewed. Then, an approximate quantum method treating both two-body and three-body collisions simultaneously and on equal footing is used to calculate cross sections for the reaction Ne{sub 2} + H {rightleftharpoons} Ne + Ne + H. The results provide clear quantum evidence that direct three-body collisions do contribute significantly to recombination and CID.

  20. NA35: sulphur-gold collision

    CERN Multimedia

    1991-01-01

    In this image the real particles produced by the collision of a 6400 GeV sulphur ion with a gold target can be seen as they pass through a streamer chamber. Streamer chambers consist of a gas chamber through which a strong pulsed electric field is passed, creating sparks as a charged particle passes through it. The NA35 experiment, which was in operation in the 1980s, was part of CERN's ongoing heavy ion project.

  1. Catalytic Reactions in Heavy-ion Collisions

    CERN Document Server

    Kolomeitsev, E E

    2011-01-01

    We discuss a new type of reactions of a phi meson production on hyperons, pi Y--> phi Y and anti-kaons bar-K N --> phi Y. These reactions are not suppressed according to Okubo-Zweig-Iizuka rule and can be a new efficient source of phi mesons in a nucleus-nucleus collision. We discuss how these reactions can affect the centrality dependence and the rapidity distributions of the phi yield.

  2. Catalytic reactions in heavy-ion collisions

    Science.gov (United States)

    Kolomeitsev, E. E.; Tomášik, B.

    2012-06-01

    We discuss a new type of reactions of a ϕ-meson production on hyperons, πY → ϕY and antikaons -KN → ϕY. These reactions are not suppressed according to Okubo-Zweig-Iizuka rule and can be a new efficient source of ϕ mesons in a nucleus-nucleus collision. We discuss how these reactions can affect the centrality dependence and the rapidity distributions of the ϕ yield.

  3. Femtoscopy in Relativistic Heavy Ion Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Lisa, M; Pratt, S; Soltz, R A; Wiedemann, U

    2005-07-29

    Analyses of two-particle correlations have provided the chief means for determining spatio-temporal characteristics of relativistic heavy ion collisions. We discuss the theoretical formalism behind these studies and the experimental methods used in carrying them out. Recent results from RHIC are put into context in a systematic review of correlation measurements performed over the past two decades. The current understanding of these results are discussed in terms of model comparisons and overall trends.

  4. Azimuthal correlations in photon-photon collisions

    CERN Document Server

    Artéaga-Romero, N; Kessler, P; Ong, S; Panella, O

    1995-01-01

    Using the general helicity formula for \\gamma^* \\gamma^* collisions, we are showing that it should be possible to determine a number of independent ``structure functions'', i.e. linear combinations of elements of the two-photon helicity tensor, through azimuthal correlations in two-body or quasi two-body reactions induced by the photon-photon interaction, provided certain experimental conditions are satisfied. Numerical results of our computations are presented for some particular processes and dynamic models.

  5. Multiparticle collision dynamics in porous media

    CERN Document Server

    Matyka, Maciej

    2016-01-01

    We adopt the multiparticle collision dynamics method to simulate fluid flows in porous media. For this, the particle-level drag force is introduced into the original algorithm. The force hinder the flow resulting in global resistance and decrease of permeability. The extended algorithm is validated in the flow through fully porous channel with analytical solution. Basic properties of the solver are investigated including its dependency of permeability on model parameters.

  6. b-flavour tagging in pp collisions

    CERN Multimedia

    Birnkraut, Alex

    2015-01-01

    An essential ingredient of all time-dependent CP violation studies of B mesons is the ability to tag the initial flavour of the B meson. The harsh environment of 7 and 8 TeV pp collisions makes this a particularly difficult enterprise. We report progresses in the flavour tagging of B0 and Bs mesons, including developments of novel techniques like the use of an opposite side charm tagger.

  7. Collisions of planetesimals and formation of planets

    CERN Document Server

    Dvorak, Rudolf; Süli, Áron; Schäfer, Christoph M; Speith, Roland; Burger, Christoph

    2015-01-01

    We present preliminary results of terrestrial planet formation using on the one hand classical numerical integration of hundreds of small bodies on CPUs and on the other hand -- for comparison reasons -- the results of our GPU code with thousands of small bodies which then merge to larger ones. To be able to determine the outcome of collision events we use our smooth particle hydrodynamics (SPH) code which tracks how water is lost during such events.

  8. Collisions of Planetesimals and Formation of Planets

    Science.gov (United States)

    Dvorak, Rudolf; Maindl, Thomas I.; Süli, Áron; Schäfer, Christoph M.; Speith, Roland; Burger, Christoph

    2016-01-01

    We present preliminary results of models of terrestrial planet formation using on the one hand classical numerical integration of hundreds of small bodies on CPUs and on the other hand-for comparison-the results of our GPU code with thousands of small bodies which then merge to larger ones. To be able to determine the outcome of collision events we use our smooth particle hydrodynamics (SPH) code which tracks how water is lost during such events.

  9. Dynamics of reactive collisions by optical methods

    Science.gov (United States)

    Ureña, A. González; Vetter, R.

    This paper reviews recent developments in the study of reactive collisions using optical methods. Although the basic approach is from the experimental viewpoint, attention is paid to the conceptual and theoretical aspects of the physics underlying modern reaction dynamics. After a brief resume of basic concepts and definitions on both scalar and vectorial quantities characterizing the chemical reaction, a significant body of this paper describes the recent achievements using laser techniques, mainly via laser-induced fluorescence, and chemiluminescence. Both high-resolution crossed-beam and high-resolution bulb studies are presented in a complementary fashion, as they provide a detailed picture of reaction dynamics through the measurement of quantum state specific differential cross-sections. Specific examples include the use of Doppler resolved laser-induced fluorescence, multiphoton ionization or Cars studies. Some examples are also included based on the use of product imaging techniques, the novel approach of obtaining quantum state resolved differential cross-sections for chemical reactions. In addition, new data on the collision energy dependence of the collision cross-section, i.e. the excitation function, obtained by highly sensitive collision energy cross-beam techniques is also presented and reviewed. Another part of the paper is dedicated to recent advances in the study of reaction dynamics using electronically excited species. Emphasis is placed not only on the opening of new channels for chemical reactions but also on the possible outcome of the reaction products associated with the different symmetries of the excited potential energy surfaces. Finally, a section is dedicated to recent developments in studies carried out in the area of van der Waals and cluster reactions. The possibility of clocking the chemical act as well as very efficient trapping of reaction intermediates is illustrated with some examples. Throughout the whole paper care is taken to

  10. 2017 LHC test collisions in ATLAS

    CERN Multimedia

    ATLAS Collaboration

    2017-01-01

    Test collisions are one of the many steps on the way to the LHC restart. The beams are neither quiet nor stable enough to ramp up the pixel and SCT, but other subsystems are on. On 10.05.2017 the ATLAS shift crew counted many women responsible for overall coordination, run control, high level trigger, data quality, safety and subsystems such as LAr calorimeter and muon spectrometer.

  11. Hadron thermodynamics in relativistic nuclear collisions

    Science.gov (United States)

    Ammiraju, P.

    1985-01-01

    Various phenomenological models based on statistical thermodynamical considerations were used to fit the experimental data at high P sub T to a two temperature distribution. Whether this implies that the two temperatures belong to two different reaction mechanisms, or consequences of Lorentz-contraction factor, or related in a fundamental way to the intrinsic thermodynamics of Space-Time can only be revealed by further theoretical and experimental investigations of high P sub T phenomena in extremely energetic hadron-hadron collisions.

  12. Direct photons in heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Baeuchle, Bjoern

    2010-12-13

    Direct photon emission from heavy-ion collisions has been calculated and compared to available experimental data. Three different models have been combined to extract direct photons from different environments in a heavy-ion collision: Thermal photons from partonic and hadronic matter have been extracted from relativistic, non-viscous 3+1-dimensional hydrodynamic calculations. Thermal and non-thermal photons from hadronic interactions have been calculated from relativistic transport theory. The impact of different physics assumptions about the thermalized matter has been studied. The models used for the determination of photons from both hydrodynamic and transport calculations have been elucidated and their numerical properties tested. The origin of direct photons, itemised by emission stage, emission time, channel and baryon number density, has been investigated for various systems, as have the transverse momentum spectra and elliptic flow patterns of direct photons. Taking into account the full (vacuum) spectral function of the rho-meson decreases the direct photon emission by approximately 10% at low photon transverse momentum. In all systems that have been considered -- heavy-ion collisions at E{sub lab}=35 AGeV and 158 AGeV, (s{sub NN}){sup 1/2}=62.4 GeV, 130 GeV and 200 GeV -- thermal emission from a system with partonic degrees of freedom is greatly enhanced over that from hadronic systems, while the difference between the direct photon yields from a viscous and a non-viscous hadronic system (transport vs. hydrodynamics) is found to be very small. Predictions for direct photon emission in central U+U-collisions at 35 AGeV have been made. (orig.)

  13. Angular Momentum Sharing in Dissipative Collisions

    Science.gov (United States)

    Casini, G.; Poggi, G.; Bini, M.; Calamai, S.; Maurenzig, P. R.; Olmi, A.; Pasquali, G.; Stefanini, A. A.; Taccetti, N.; Steckmeyer, J. C.; Laforest, R.; Saint-Laurent, F.

    1999-09-01

    Light charged particles emitted by the projectilelike fragment were measured in the direct and reverse collision of 93Nb and 116Sn at 25A MeV. The experimental multiplicities of hydrogen and helium particles as a function of the primary mass of the emitting fragment show evidence for a correlation with net mass transfer. The ratio of hydrogen and helium multiplicities points to a dependence of the angular momentum sharing on the net mass transfer.

  14. Angular momentum sharing in dissipative collisions

    CERN Document Server

    Casini, G; Bini, M; Calamai, S; Maurenzig, P R; Olmi, A; Pasquali, G; Stefanini, A A; Taccetti, N; Steckmeyer, J C; Laforest, R; Saint-Laurent, F

    1999-01-01

    Light charged particles emitted by the projectile-like fragment were measured in the direct and reverse collision of $^{93}$Nb and $^{116}$Sn at 25 AMeV. The experimental multiplicities of Hydrogen and Helium particles as a function of the primary mass of the emitting fragment show evidence for a correlation with net mass transfer. The ratio of Hydrogen and Helium multiplicities points to a dependence of the angular momentum sharing on the net mass transfer.

  15. Fan affinity laws from a collision model

    CERN Document Server

    Bhattacharjee, Shayak

    2012-01-01

    The performance of a fan is usually estimated from hydrodynamical considerations. The calculations are long and involved and the results are expressed in terms of three affinity laws. In this work we use kinetic theory to attack this problem. A hard sphere collision model is used, and subsequently a correction to account for the flow behaviour of air is incorporated. Our calculations prove the affinity laws and provide numerical estimates of the air delivery, thrust and drag on a rotating fan.

  16. Mobile Robot Collision Avoidance in Human Environments

    OpenAIRE

    Lingqi Zeng; Gary M. Bone

    2013-01-01

    Collision avoidance is a fundamental requirement for mobile robots. Avoiding moving obstacles (also termed dynamic obstacles) with unpredictable direction changes, such as humans, is more challenging than avoiding moving obstacles whose motion can be predicted. Precise information on the future moving directions of humans is unobtainable for use in navigation algorithms. Furthermore, humans should be able to pursue their activities unhindered and without worrying about the robots around them....

  17. Optically controlled collisions of biological objects

    Science.gov (United States)

    Davies, Benjamin J.; Kishore, Rani; Mammen, Mathai; Helmerson, Kristian; Choi, Seok-Ki; Phillips, William D.; Whitesides, George M.

    1998-04-01

    We have developed a new assay in which two mesoscale particles are caused to collide using two independently controlled optical tweezers. This assay involves the measurement of the adhesion probability following a collision. Since the relative orientation, impact parameter (i.e., distance of closest approach), and collision velocity of the particles, as well as the components of the solution, are all under the user's control, this assay can mimic a wide range of biologically relevant collisions. We illustrate the utility of our assay by evaluating the adhesion probability of a single erythrocyte (red blood cell) to an influenza virus-coated microsphere, in the presence of sialic acid-bearing inhibitors of adhesion. This probability as a function of inhibitor concentration yields a measure of the effectiveness of the inhibitor for blocking viral adhesion. Most of the inhibition constants obtained using the tweezers agree well with those obtained from other techniques, although the inhibition constants for the best of the inhibitors were beyond the limited resolution of conventional assays. They were readily evaluated using our tweezers-based assay, however, and prove to be the most potent inhibitors of adhesion between influenza virus and erythrocytes ever measured. Further studies are underway to investigate the effect of collision velocity on the adhesion probability, with the eventual goal of understanding the various mechanisms of inhibition (direct competition for viral binding sites versus steric stabilization). Analysis of these data also provide evidence that the density of binding sites may be a crucial parameter in the application of this assay and polymeric inhibition in general.

  18. Highly-anisotropic hydrodynamics for central collisions

    CERN Document Server

    Ryblewski, Radoslaw

    2016-01-01

    The framework of leading-order anisotropic hydrodynamics is supplemented with realistic equation of state and self-consistent freeze-out prescription. The model is applied to central proton-nucleus collisions. The results are compared to those obtained within standard Israel-Stewart second-order viscous hydrodynamics. It is shown that the resulting hadron spectra are highly-sensitive to the hydrodynamic approach that has been used.

  19. Studying Proton-Proton Collisions Using Pythia

    Science.gov (United States)

    Zolotov, Adi

    2004-10-01

    At Brookhaven National Lab, the RHIC experiments are currently investigating, on a subatomic level, what happens when heavy ions collide at high speeds. This is done in order to create such high temperatures and densities that quarks are no longer bound to one another. This state of matter is called the Quark-Gluon Plasma (QGP). Evidence for the existence of the QGP may be the quenching of hadron jets, which occurs when the fast quarks or gluons lose so much energy in the hot, dense medium that they cannot survive. Then the jets of particles that these particles usually result in cannot be made. By studying the particle yield at high transverse momentum (Pt), one can probe what is happening to the jets created during collisions. Using Pythia, a standard model event generator based on the Lund String Model, we study jets of particles created when elementary protons collide. Then we know what should happen to jets at high transverse momentum transfer, when no QGP is present. Comparing the pt spectrum of jet partners generated by Pythia to RHIC results for proton-proton collisions shows that the two do in fact agree. This not only insures that the analysis of RHIC data is correct, but it also establishes a basis for comparison for Au-Au collisions. Comparing d+Au collision data to the Pythia Pt spectrum of jets with leading baryon and meson triggers, we found good agreement. Thus the jet production does not change drastically in nature in the presence of a cold nuclear medium.

  20. Cross Sections for Electron Collisions with Methane

    Energy Technology Data Exchange (ETDEWEB)

    Song, Mi-Young, E-mail: mysong@nfri.re.kr; Yoon, Jung-Sik [Plasma Technology Research Center, National Fusion Research Institute, 814-2 Osikdo-dong, Gunsan, Jeollabuk-do 573-540 (Korea, Republic of); Cho, Hyuck [Department of Physics, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Itikawa, Yukikazu [Institute of Space and Astronautical Science, Sagamihara 252-5210 (Japan); Karwasz, Grzegorz P. [Faculty of Physics, Astronomy and Applied Informatics, University Nicolaus Copernicus, Grudziadzka 5, 87100 Toruń (Poland); Kokoouline, Viatcheslav [Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States); Nakamura, Yoshiharu [6-1-5-201 Miyazaki, Miyamae, Kawasaki 216-0033 (Japan); Tennyson, Jonathan [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2015-06-15

    Cross section data are compiled from the literature for electron collisions with methane (CH{sub 4}) molecules. Cross sections are collected and reviewed for total scattering, elastic scattering, momentum transfer, excitations of rotational and vibrational states, dissociation, ionization, and dissociative attachment. The data derived from swarm experiments are also considered. For each of these processes, the recommended values of the cross sections are presented. The literature has been surveyed through early 2014.

  1. Statistical Hadronisation in Positron-proton Collisions

    CERN Document Server

    Urmossy, Karoly

    2016-01-01

    We reproduce charged hadron momentum fraction distributions measured in diffractive positron-proton collisions resulting in hadronic final states with two jets of approximately equal energies. Our hadronisation model is based on microcanonical statistics and negative binomial multiplicity fluctuations. We describe the scale dependence of the fit parameters of the model with formulas obtained by approximating the exact solution of the DGLAP equation in the $\\phi^3$ theory with leading order splitting function and 1-loop coupling.

  2. Oscillating collision of the granular chain on static wall

    Science.gov (United States)

    Ma, Liang; Huang, Decai; Chen, Weizhong; Jiao, Tengfei; Sun, Min; Hu, Fenglan; Su, Jiaye

    2017-02-01

    Collision of the granular chain on static wall is investigated by discrete element method. Collision time and traveling time are proposed on the basis of the characteristics of the collision of a single grain with a wall and the propagation of interaction force wave in a granular chain to explain the collision process. Simulation results show that an oscillating collision force is generated when the force waves successively arrive at the wall. For the collision of a mono-dispersed chain, the simulation data are in good agreement with the predicted relationship between the maximum chain length of nmax and the first maximum collision force FA. Rigid wall and soft wall are defined as nmax = 1 and nmax ≥ 2, respectively. Two similar processes of oscillating collisions occur when a light or a heavy impure grain is introduced. In these processes, two maximum collision forces, namely, FA and FB, are observed, respectively. The simulation results about the influence of the mass and position of light impure grain on the collision force FB further confirm our theoretical predictions.

  3. Non-collision backgrounds in ATLAS

    CERN Document Server

    Gibson, S M; The ATLAS collaboration

    2012-01-01

    The proton-proton collision events recorded by the ATLAS experiment are on top of a background that is due to both collision debris and non-collision components. The latter comprises of three types: beam-induced backgrounds, cosmic particles and detector noise. We present studies that focus on the first two of these. We give a detailed description of beam-related and cosmic backgrounds based on the full 2011 ATLAS data set, and present their rates throughout the whole data-taking period. Studies of correlations between tertiary proton halo and muon backgrounds, as well as, residual pressure and resulting beam-gas events seen in beam-condition monitors will be presented. Results of simulations based on the LHC geometry and its parameters will be presented. They help to better understand the features of beam-induced backgrounds in each ATLAS sub-detector. The studies of beam-induced backgrounds in ATLAS reveal their characteristics and serve as a basis for designing rejection tools that can be applied in physic...

  4. Photon-Photon Collisions -- Past and Future

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Stanley J.; /SLAC

    2005-12-02

    I give a brief review of the history of photon-photon physics and a survey of its potential at future electron-positron colliders. Exclusive hadron production processes in photon-photon and electron-photon collisions provide important tests of QCD at the amplitude level, particularly as measures of hadron distribution amplitudes. There are also important high energy {gamma}{gamma} and e{gamma} tests of quantum chromodynamics, including the production of jets in photon-photon collisions, deeply virtual Compton scattering on a photon target, and leading-twist single-spin asymmetries for a photon polarized normal to a production plane. Since photons couple directly to all fundamental fields carrying the electromagnetic current including leptons, quarks, W's and supersymmetric particles, high energy {gamma}{gamma} collisions will provide a comprehensive laboratory for Higgs production and exploring virtually every aspect of the Standard Model and its extensions. High energy back-scattered laser beams will thus greatly extend the range of physics of the International Linear Collider.

  5. Half collision resonance phenomena in molecules

    Energy Technology Data Exchange (ETDEWEB)

    Maximo Garcia-Sucre (Universidad Central de Venezuela, Caracas (Venezuela)); Raseev, G. (Paris-11 Univ., 91 - Orsay (France)); Ross, S.C. (New Brunswick Univ., Fredericton, NB (Canada)) (eds.)

    1991-01-01

    The Escuela Latinoamericana de Fisica (ELAF) is a series of meeting s that for 28 years has played an important role in research-level teaching of physics in Latin America. This book contains the proceedings of ELAF 90 which was held at the Instituto Venezolano de Investigaciones Cientificas (IVIC) in Caracas, Venezuela from July 23 to August 3, 1990, as part of the commemoration of the 30th anniversary of IVIC. In contrast to previous ELAF's that were of general scope, ELAF 90 centered on a particular subject matter: Half Collisional Resonance Phenomena in Molecules, Experimental and Theoretical Approaches. The term Half Collision'' refers to the fragmentation of a molecular system following is excitation by light. The lack of an incident fragmentation of a molecular system following is excitation by light. The lack of an incident particle (other than the photon) in the fragmentation process is what leads to the term. The purpose of this volume is to present current results in the experimental and theoretical study of half collisions and also to include pedagogical papers at an introductory or intermediate level. The contributions are grouped into several sections; light sources; ionization; dissociation-experimental; dissociation-theory; competition between ionization and dissociation; and particle-molecule collisions.

  6. SPH simulations of high-speed collisions

    Science.gov (United States)

    Rozehnal, Jakub; Broz, Miroslav

    2016-10-01

    Our work is devoted to a comparison of: i) asteroid-asteroid collisions occurring at lower velocities (about 5 km/s in the Main Belt), and ii) mutual collisions of asteroids and cometary nuclei usually occurring at significantly higher relative velocities (> 10 km/s).We focus on differences in the propagation of the shock wave, ejection of the fragments and possible differences in the resultingsize-frequency distributions of synthetic asteroid families. We also discuss scaling with respect to the "nominal" target diameter D = 100 km, projectile velocity 3-7 km/s, for which a number of simulations were done so far (Durda et al. 2007, Benavidez et al. 2012).In the latter case of asteroid-comet collisions, we simulate the impacts of brittle or pre-damaged impactors onto solid monolithic targets at high velocities, ranging from 10 to 15 km/s. The purpose of this numerical experiment is to better understand impact processes shaping the early Solar System, namely the primordial asteroid belt during during the (late) heavy bombardment (as a continuation of Broz et al. 2013).For all hydrodynamical simulations we use a smoothed-particle hydrodynamics method (SPH), namely the lagrangian SPH3D code (Benz & Asphaug 1994, 1995). The gravitational interactions between fragments (re-accumulation) is simulated with the Pkdgrav tree-code (Richardson et al. 2000).

  7. LHC Report: Towards stable beams and collisions

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    Over the past two weeks, the LHC re-commissioning with beam has continued at a brisk pace. The first collisions of 2011 were produced on 2 March, with stable beams and collisions for physics planned for the coming days. Low intensity beams with just a few bunches of particles were used to test the energy ramp to 3.5 TeV and the squeeze. The results were successful and, as a by-product, the first collisions of 2011 were recorded 2 March. One of the main activities carried out by the operation teams has been the careful set-up of the collimation system, and the injection and beam dump protection devices. The collimation system provides essential beam cleaning, preventing stray particles from impacting other elements of the machine, particularly the superconducting magnets. In addition to the collimation system, also the injection and beam dump protection devices perform a vital machine protection role, as they detect any beam that might be mis-directed during rare, but not totally unavoidable, hardware hiccups...

  8. Collisions of Rydberg Atoms with Charged Particles

    Science.gov (United States)

    MacAdam, Keith B.

    2000-10-01

    The long range of Coulomb interactions, together with the large size, long radiative lifetimes and high state densities of highly excited Rydberg atoms, results in inelastic collision cross sections of prodigious size -- often large enough to outweigh small number densities in astrophysica and cool laboratory plasmas -- and in other unusual features. This talk will provide: (a) a brief survey of the significant features of collisions between electron or positive ions and state-selected Rydberg atoms and of recent experiments( O. Makarov and K.B. MacAdam, Phys. Rev. A 60), 2131-8 (1999); and K.B. MacAdam, J.C. Day and D.M. Homan, Comm. At. Mol. Phys./Comm. Mod. Phys. 1(2), Part D, 57-73 (1999). to investigate them; (b) an introduction to some of the special techniques that have been developed(J.L. Horn, D.M. Homan, C.S. Hwang, W.L. Fuqua III and K.B. MacAdam, Rev. Sci. Instrum. 69), 4086-93 (1998). for preparation, manipulation and detection of Rydberg atoms; and (c) a glimpse at new directions in Rydberg atom collision research.

  9. Electromagnetic Radiations from Heavy Ion Collision

    Directory of Open Access Journals (Sweden)

    Payal Mohanty

    2013-01-01

    Full Text Available In this review, we have discussed the different sources of photons and dileptons produced in heavy ion collision (HIC. The transverse momentum (pT spectra of photons for different collision energies are analyzed with a view of extracting the thermal properties of the system formed in HIC. We showed the effect of viscosity on pT spectra of produced thermal photons. The dilepton productions from hot hadrons are considered including the spectral change of light vector mesons in the thermal bath. We have analyzed the pT and invariant mass (M spectra of dileptons for different collision energies too. As the individual spectra are constrained by certain unambiguous hydrodynamical inputs, so we evaluated the ratio of photon to dilepton spectra, Rem, to overcome those quantities. We argue that the variation of the radial velocity extracted from Rem with M is indicative of a phase transition from the initially produced partons to hadrons. In the calculations of interferometry involving dilepton pairs, it is argued that the nonmonotonic variation of HBT radii with invariant mass of the lepton pairs signals the formation of quark gluon plasma in HIC. Elliptic flow (v2 of dilepton is also studied at sNN=2.76 TeV for 30–40% centrality using the (2+1d hydrodynamical model.

  10. Collision Statistics of Driven Polydisperse Granular Gases

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhi-Yuan; ZHANG Duan-Ming; LI Zhong-Ming; YANG Feng-Xia; GUO Xin-Ping

    2008-01-01

    We present a dynamicai model of two-dimensional polydisperse granular gases with fractal size distribution, in which the disks are subject to inelastic mutual collisions and driven by standard white noise. The inhomogeneity of the disk size distribution can be measured by a fractal dimension df. By Monte Carlo simulations, we have mainly investigated the effect of the inhomogeneity on the statistical properties of the system in the same inelasticity case. Some novel results are found that the average energy of the system decays exponentiaUy with a tendency to achieve a stable asymptotic value, and the system finally reaches a nonequilibrium steady state after a long evolution time. Furthermore, the inhomogeneity has great influence on the steady-state statisticai properties. With the increase of the fractal dimension df, the distributions of path lengths and free times between collisions deviate more obviously from expected theoretical forms for elastic spheres and have an overpopulation of short distances and time bins. The collision rate increases with df, but it is independent of time. Meanwhile, the velocity distribution deviates more strongly from the Gaussian one, but does not demonstrate any apparent universal behavior.

  11. Binary droplet collision at high Weber number.

    Science.gov (United States)

    Pan, Kuo-Long; Chou, Ping-Chung; Tseng, Yu-Jen

    2009-09-01

    By using the techniques developed for generating high-speed droplets, we have systematically investigated binary droplet collision when the Weber number (We) was increased from the range usually tested in previous studies on the order of 10 to a much larger value of about 5100 for water (a droplet at 23 m/s with a diameter of 0.7 mm). Various liquids were also used to explore the effects of viscosity and surface tension. Specifically, beyond the well-known regimes at moderate We's, which exhibited coalescence, separation, and separation followed by satellite droplets, we found different behaviors showing a fingering lamella, separation after fingering, breakup of outer fingers, and prompt splattering into multiple secondary droplets as We was increased. The critical Weber numbers that mark the boundaries between these impact regimes are identified. The specific impact behaviors, such as fingering and prompt splattering or splashing, share essential similarity with those also observed in droplet-surface impacts, whereas substantial variations in the transition boundaries may result from the disparity of the boundary conditions at impacts. To compare the outcomes of both types of collisions, a simple model based on energy conservation was carried out to predict the maximum diameter of an expanding liquid disk for a binary droplet collision. The results oppose the dominance of viscous drag, as proposed by previous studies, as the main deceleration force to effect a Rayleigh-Taylor instability and ensuing periphery fingers, which may further lead to the formations of satellite droplets.

  12. Collision of two black holes: Theoretical framework

    Energy Technology Data Exchange (ETDEWEB)

    Smarr, L.; Cadez, A.; DeWitt, B.; Eppley, K.

    1976-11-15

    Highly nonspherical time-dependent collisions between black holes may be powerful sources of gravitational radiation. We consider various attempts at estimating the efficiency of the generation of radiation by such collisions. To determine the actual efficiency as well as to understand the details of the dynamical coalescence of black-hole event horizons, we have developed a numerical method for solving the Einstein gravitational field equations in these high-velocity strong-field regions. The head-on collision of two nonrotating vacuum black holes is chosen as an example of our technique. We use the geometrodynamical model of a black hole as an Einstein-Rosen bridge. The initial data to be evolved are the time-symmetric conformally flat data discovered by Misner. A new set of spatial coordinates for these data is derived. Then the general space plus time decomposition of Einstein's equations is presented and specialized to the axisymmetric nonrotating case. Details of the evolution will be given in later papers. (AIP)

  13. New Results for Ultraperipheral Heavy Ion Collisions

    CERN Document Server

    Szczurek, Antoni; Lebiedowicz, Piotr; Schäfer, Wolfgang

    2016-01-01

    We discuss diphoton semi(exclusive) production in ultraperipheral $PbPb$ collisions at energy of $\\sqrt{s_{NN}}=$ 5.5 TeV (LHC). The nuclear calculations are based on equivalent photon approximation in the impact parameter space. The cross sections for elementary $\\gamma \\gamma \\to \\gamma \\gamma$ subprocess are calculated including three different mechanisms: box diagrams with leptons and quarks in the loops, a VDM-Regge contribution with virtual intermediate hadronic excitations of the photons and the two-gluon exchange contribution (formally three-loops). We got relatively high cross sections in $PbPb$ collisions. This opens a possibility to study the $\\gamma \\gamma \\to \\gamma \\gamma$ (quasi)elastic scattering at the LHC. We find that the cross section for elastic $\\gamma\\gamma$ scattering could be measured in the lead-lead collisions for the diphoton invariant mass up to $W_{\\gamma\\gamma} \\approx 15-20$ GeV. We identify region(s) of phase space where the two-gluon exchange contribution becomes important in...

  14. Granting silence to avoid wireless collisions

    KAUST Repository

    Choi, Jung Il

    2010-10-01

    We describe grant-to-send, a novel collision avoidance algorithm for wireless mesh networks. Rather than announce packets it intends to send, a node using grant-to-send announces packets it expects to hear others send. We present evidence that inverting collision avoidance in this way greatly improves wireless mesh performance. Evaluating four protocols from 802.11 meshes and 802.15.4 sensor networks, we find that grant-to-send matches or outperforms CSMA and RTS/CTS in all cases. For example, in a 4-hop UDP flow, grantto- send can achieve 96% of the theoretical maximum throughput while maintaining a 99.9% packet delivery ratio. Grant-tosend is also general enough to replace protocol-specific collision avoidance mechanisms common to sensor network protocols. Grant-to-send is simple. For example, incorporating it into 802.11 requires only 11 lines of driver code and no hardware changes. Furthermore, as it reuses existing 802.11 mechanisms, grant-to-send inter-operates with current networks and can be incrementally deployed. © 2010 IEEE.

  15. On Continent-Continent Point-Collision and Ultrahigh-Pressure Metamorphism

    Institute of Scientific and Technical Information of China (English)

    董树文; 武红岭; 刘晓春; 薛怀民

    2002-01-01

    rocks—the point-collision model. This model conforms to the basic principles of the mechanics and also to the geologic records and process in the Dabie orogenic belt. It can explain why UHP rocks do not exist along the entire length of the collisional orogen but occur in some particular positions. The authors also propose that the eastern and western corners of the Himalaya collision zone are typical point-collision areas and that almost all UHP metamorphism of continental crustal rocks occurred in the two particular positions.

  16. Coalescence collision of liquid drops I: Off-center collisions of equal-size drops

    Directory of Open Access Journals (Sweden)

    Alejandro Acevedo-Malavé

    2011-09-01

    Full Text Available The Smoothed Particle Hydrodynamics method (SPH is used here to model off-center collisions of equal-size liquid drops in a three-dimensional space. In this study the Weber number is calculated for several conditions of the droplets dynamics and the velocity vector fields formed inside the drops during the collision process are shown. For the permanent coalescence the evolution of the kinetic and internal energy is shown and also the approaching to equilibrium of the resulting drop. Depending of the Weber number three possible outcomes for the collision of droplets is obtained: permanent coalescence, flocculation and fragmentation. The fragmentation phenomena are modeled and the formation of small satellite drops can be seen. The ligament that is formed follows the “end pinching” mechanism and it is transformed into a flat structure.

  17. Coalescence collision of liquid drops II: Off-center collisions of unequal-size drops

    Directory of Open Access Journals (Sweden)

    Alejandro Acevedo-Malavé

    2011-09-01

    Full Text Available We applied the Smoothed Particle Hydrodynamics method to simulate for first time in the three-dimensional space the hydrodynamic off-center collisions of unequal-size liquid drops in a vacuum environment. The Weber number for several conditions of the droplets dynamics is determined. Also the velocity vector fields inside the drops are shown in the collision process. The evolution of the kinetic and internal energy is shown for the permanent coalescence case. The resulting drops tend to deform, and depending of the Weber number two possible outcomes for the collision of droplets arise: either permanent coalescence or flocculation. In the permanent coalescence of the drops a fragmentation case is modeled, yielding the formation of little satellite droplets.

  18. Contributions of collision rate and collision efficiency to erythrocyte aggregation in postcapillary venules at low flow rates.

    Science.gov (United States)

    Kim, Sangho; Zhen, Janet; Popel, Aleksander S; Intaglietta, Marcos; Johnson, Paul C

    2007-09-01

    Red blood cell aggregation at low flow rates increases venous vascular resistance, but the process of aggregate formation in these vessels is not well understood. We previously reported that aggregate formation in postcapillary venules of the rat spinotrapezius muscle mainly occurs in a middle region between 15 and 30 microm downstream from the entrance. In light of the findings in that study, the main purpose of this study was to test two hypotheses by measuring collision frequency along the length of the venules during low flow. We tested the hypothesis that aggregation rarely occurs in the initial 15-microm region of the venule because collision frequency is very low. We found that collision frequency was lower than in other regions, but collision efficiency (the ratio of aggregate formation to collisions) was almost nil in this region, most likely because of entrance effects and time required for aggregation. Radial migration of red blood cells and Dextran 500 had no effect on collision frequency. We also tested the hypothesis that aggregation was reduced in the distal venule region because of the low aggregability of remaining nonaggregated cells. Our findings support this hypothesis, since a simple model based on the ratio of aggregatable to nonaggregatable red blood cells predicts the time course of collision efficiency in this region. Collision efficiency averaged 18% overall but varied from 0 to 52% and was highest in the middle region. We conclude that while collision frequency influences red blood cell aggregate formation in postcapillary venules, collision efficiency is more important.

  19. Conservative bin-to-bin fractional collisions

    Science.gov (United States)

    Martin, Robert

    2016-11-01

    Particle methods such as direct simulation Monte Carlo (DSMC) and particle-in-cell (PIC) are commonly used to model rarefied kinetic flows for engineering applications because of their ability to efficiently capture non-equilibrium behavior. The primary drawback to these methods relates to the poor convergence properties due to the stochastic nature of the methods which typically rely heavily on high degrees of non-equilibrium and time averaging to compensate for poor signal to noise ratios. For standard implementations, each computational particle represents many physical particles which further exacerbate statistical noise problems for flow with large species density variation such as encountered in flow expansions and chemical reactions. The stochastic weighted particle method (SWPM) introduced by Rjasanow and Wagner overcome this difficulty by allowing the ratio of real to computational particles to vary on a per particle basis throughout the flow. The DSMC procedure must also be slightly modified to properly sample the Boltzmann collision integral accounting for the variable particle weights and to avoid the creation of additional particles with negative weight. In this work, the SWPM with necessary modification to incorporate the variable hard sphere (VHS) collision cross section model commonly used in engineering applications is first incorporated into an existing engineering code, the Thermophysics Universal Research Framework. The results and computational efficiency are compared to a few simple test cases using a standard validated implementation of the DSMC method along with the adapted SWPM/VHS collision using an octree based conservative phase space reconstruction. The SWPM method is then further extended to combine the collision and phase space reconstruction into a single step which avoids the need to create additional computational particles only to destroy them again during the particle merge. This is particularly helpful when oversampling the

  20. Inclined transpression in the Neka Valley, eastern Alborz, Iran

    Science.gov (United States)

    Nabavi, Seyed Tohid; Díaz-Azpiroz, Manuel; Talbot, Christopher J.

    2016-09-01

    Three major nappes in the Neka Valley in the eastern Alborz Mountains of Iran allow the Cimmerian to present convergence following the oblique collision between Iran and the southern margin of Eurasia. This work reports the identification of an inclined transpression zone recognized by field investigations and strain analyses of the geometries of formations and detailed mesoscopic structural analyses of multiple faults, folds and a cleavage. The main structures encountered include refolded recumbent asymmetric fold nappes, highly curved fold hinges, in a transpression zone that dips 37° to the NW between boundaries thrusts striking from N050° to N060°. The β angle (the angle between the zone boundary and direction of horizontal far-field shortening) is about 80°. The north-west and south-east boundaries of this zone coincide with the Haji-abad thrust and the Shah-Kuh thrust, respectively. Fold axes generally trend NE-SW and step to both right and left as a result of strike-slip components of fault displacements. Strain analyses using Fry's method on macroscopic ooids and fusulina deformed into oblate ellipsoids indicate that the natural strain varies between 2.1 and 3.14. The estimated angle between the maximum instantaneous strain axis (ISAmax) and the transpression zone boundary (θ') is between 6° and 20°. The estimated oblique convergence angle (α), therefore, ranges between 31° and 43°. The average kinematic vorticity number (W k ) is 0.6, in a zone of sinistral pure shear-dominated inclined triclinic transpression. These results support the applicability of kinematic models of triclinic transpression to natural brittle-ductile shear zones.

  1. Lambda Polarization in Lead-Lead Collisions

    Science.gov (United States)

    Schillings, Eelco

    2003-05-01

    In this thesis the production and polarization of Lambda particles produced in Pb-Pb collisions at a beam energy of 158 GeV/c per nucleon are studied. In these collisions nuclear matter is compressed and heated and under these conditions it is possible that a quark-gluon plasma (QGP) is created. In a QGP the boundaries between individual particles disappear and the quarks and gluons can move around freely. One of the probes to study the creation of the QGP is the so-called Strangeness Enhancement, which is the enhanced production of strange particles, with respect to the production in proton-induced collisions. Another proposed signature of the QGP is the disappearance of transverse Lambda polarization around mid-rapidity. Transverse Lambda polarization can occur when the spin of the produced Lambda has its preferred direction perpendicular to the production plane. In proton-proton and proton-nucleus collisions a negative transverse polarization has been observed and its magnitude was largest for the Lambdas produced in the direction of the beam (i.e. at high xF). This is an indication that the projectile plays an important role and in semi-classical models the following picture is assumed: in the interaction region a spin-zero ud-diquark from the projectile recombines with a negatively polarized s-quark from the sea. This s-quark also gives transverse momentum (pT) to the Lambda and as a result the polarization is dependent on pT. Recently it has been shown that also in nucleus-nucleus collisions a negative transverse polarization occurs, so even in large interaction regions the information on the nature of the projectile is kept. In a QGP however this information is lost and no production plane can be defined. This will cause the transverse polarization of the Lambdas produced in this region to disappear. The transverse polarization of the produced Lambdas has been measured in the NA57 experiment at CERN around two values of xF: for xF = 0.09 a value of +0.6 +7

  2. Dielectron production in proton-proton collisions with ALICE

    CERN Document Server

    Koehler, Markus K

    Ultrarelativistic hadron collisions, such as delivered since a couple of years at the Large Hadron Collider (LHC), provide new insights into the properties of strongly interacting matter at high temperatures and densities, which is expected to have existed a few of a millionth seconds after the big bang. Electromagnetic probes, such as leptons and photons, are emitted during the entire collision. Since they do not undergo strong interactions, they reflect the entire evolution of the collision.\\\\ Pairs of leptons, so called dileptons, have the advantage compared to real photons, that they do not only carry momentum, but also have a non-zero invariant mass. The invariant mass spectrum of dileptons is a superposition of several components and allows to address different characteristics of the medium.\\\\ To understand dielectron production in heavy-ion collisions, reference measurements in proton-proton (pp) collisions are necessary. pp collisions reflect the vacuum contribution of the particles produced in heavy-...

  3. Post-collision interactions and the polarization effect in (e, 2e) collisions of helium

    Institute of Scientific and Technical Information of China (English)

    Zang Shuang-Shuang; Ge Zi-Ming

    2012-01-01

    A modified distorted-wave Born approximation (DWBA) method is used to calculate the triple differential cross sections (TDCSs) in a coplanar asymmetric geometry for the electron impact single ionization of a He (1s2) atom at intermediate and lower energies.The post-collision interaction and the polarization effect in (e,2e) collisions of helium are considered in the calculations.The polarization potentials from the damping method and density functional theory (DFT) arc compared.Theoretical results are compared with the recent experimental data.

  4. Gluon field fluctuations in nuclear collisions: Multiplicity and eccentricity distributions

    Energy Technology Data Exchange (ETDEWEB)

    Schenke, Björn [Physics Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Tribedy, Prithwish [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064 (India); Venugopalan, Raju [Physics Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2014-06-15

    We discuss different sources of fluctuations in nuclear collisions and their realization in the IP-Glasma model. We present results for multiplicity distributions in p+p and p+A collisions and compare eccentricity (ε{sub 2}, ε{sub 3}, ε{sub 4}) distributions in A + A collisions to the v{sub n} distributions in 10 centrality classes measured by the ATLAS Collaboration.

  5. Real Time Collision Detection Using Depth Texturing Spheres

    Institute of Scientific and Technical Information of China (English)

    WANG Ji; ZHAI Zhengjun; CAI Xiaobin

    2006-01-01

    In this paper, we present a novel collision detection algorithm to real time detect the collisions of objects. We generate sphere textures of objects, and use programmable graphics hardware to mapping texture and check the depth of different objects to detect the collision. We have implemented the algorithm and compared it with CULLIDE. The result shows that our algorithm is more effective than CULLIDE and has fixed executive time to suit for real-time applications.

  6. Introduction to the study of collisions between heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Bayman, B.F.

    1980-01-01

    Current investigations concerning the collisions of nuclei governed by small de Broglie wavelengths are reviewed. The wave packets localize nuclei in regions small compared to their diameters. Cross sections are examined for potential scattering, elastic scattering, quasi-molecular states, peripheral particle-transfer reactions, fusion, and deep inelastic collisions. Theories of fusion and deep inelastic collisions are summarized. This paper is in the nature of a review-tutorial. 45 references, 51 figures, 2 tables. (RWR)

  7. Piezoelectric Polymer-Based Collision Detection Sensor for Robotic Applications

    Directory of Open Access Journals (Sweden)

    J. Michael Wooten

    2015-03-01

    Full Text Available The authors present a large area collision detection sensor utilizing the piezoelectric effect of polyvinylidene fluoride film. The proposed sensor system provides high dynamic range for touch sensation, as well as robust adaptability to achieve collision detection on complex-shaped surfaces. The design allows for cohabitation of humans and robots in cooperative environments that require advanced and robust collision detection systems. Data presented in the paper are from sensors successfully retrofitted onto an existing commercial robotic manipulator.

  8. Multiplicity and theremalization time in heavy-ions collisions

    Science.gov (United States)

    Aref'eva, Irina

    2016-10-01

    We present a concise review of quark-gluon plasma formation in heavy-ions collisions within the holographic approach. In particular, we discuss how to get the total multiplicity in heavy ions collision to fit the recent experimental data. We also discuss theoretical estimations of time formation of QGP in heavy ions collision and show that different observables can give the different times of QGP formation.

  9. Multiplicity and theremalization time in heavy-ions collisions

    Directory of Open Access Journals (Sweden)

    Aref’eva Irina

    2016-01-01

    Full Text Available We present a concise review of quark-gluon plasma formation in heavy-ions collisions within the holographic approach. In particular, we discuss how to get the total multiplicity in heavy ions collision to fit the recent experimental data. We also discuss theoretical estimations of time formation of QGP in heavy ions collision and show that different observables can give the different times of QGP formation.

  10. Search for Tetraquarks in Relativistic Heavy-Ion Collisions

    Institute of Scientific and Technical Information of China (English)

    MA Zhong-Biao; GAO Chong-Shou

    2006-01-01

    Tetraquarks can be produced in relativistic heavy-ion collision. The yield of this kind of tetraquarks can increase significantly soon as the formation of QGP after the collision. If there is no phase transition after collision, the upper bound of the production of this four-quark states can be estimated from the free hadronic gas model for nuclearmatter. The relative yield ratio of tetraquark cs(s)(s) to Ω is less than 0.0164.

  11. Analysis on Uncertain Information and Actions for Preventing Collision

    Institute of Scientific and Technical Information of China (English)

    胡甚平; FANG; Quan-gen

    2007-01-01

    Discusses and analyzes the causes and characteristics of the uncertainties of the information and actions for preventing collision at sea on the basic knowledge of the collision avoidance. Describes the ways and functions of the investigations about the uncertainties of the information and actions of collision avoidance with the navigation simulators. Puts forward some suggestions for the officers to master the skills of the recognition of these uncertainties of the information and actions by the training with the simulator during the MET course.

  12. Collisions of Small Nuclei in the Thermal Model

    CERN Document Server

    Cleymans, J; Oeschler, H.; Redlich, K.; Sharma, N.

    2016-01-01

    An analysis is presented of the expectations of the thermal model for particle production in collisions of small nuclei. The maxima observed in particle ratios of strange particles to pions as a function of beam energy in heavy ion collisions, are reduced when considering smaller nuclei. Of particular interest is the $\\Lambda/\\pi^+$ ratio shows the strongest maximum which survives even in collisions of small nuclei.

  13. Mycoplasma gallopavonis in eastern wild turkeys.

    Science.gov (United States)

    Luttrell, M P; Eleazer, T H; Kleven, S H

    1992-04-01

    Serum samples and tracheal cultures were collected from eastern wild turkeys (Meleagris gallopavo sylvestris) trapped for relocation in South Carolina (USA) during 1985 to 1990. Sera were tested for Mycoplasma gallisepticum and M. synoviae by the rapid plate agglutination and hemagglutination inhibition tests and were found to be negative. Tracheal cultures were negative for all pathogenic Mycoplasma spp., including M. gallisepticum, M. synoviae, M. meleagridis, and M. iowae. However, M. gallopavonis was isolated from every group of wild turkeys tested in 1986 to 1990. These data suggest that M. gallopavonis, which is generally considered nonpathogenic, may be a common microorganism in eastern wild turkeys.

  14. A vegetation map for eastern Africa

    DEFF Research Database (Denmark)

    Lillesø, Jens-Peter Barnekow; van Breugel, Paulo; Graudal, Lars;

    2015-01-01

    The potential natural vegetation (PNV) map of eastern and southern Africa covers the countries Burundi, Ethiopia, Kenya, Uganda, Rwanda, Tanzania, and Zambia. The first version of the map was developed by various partners in East Africa and Europe in 2010 and has now reached version 2. The map...... for the right place' and potential distribution maps of the useful woody species that occur in eastern Africa. To navigate this site, please use the menu on the left. For the latest news and updates, check out our Google+ page. And if you want to contact us for questions, comments or any other reason, please...

  15. Deep-sea tsunami deposits triggered by the explosion of Santorini (3500 y BP), eastern Mediterranean

    Science.gov (United States)

    Cita, M. B.; Aloisi, G.

    2000-09-01

    The collapse of the Santorini caldera after the catastrophic eruption of the Bronze Age, 3500 y BP, caused a tsunami wave that had catastrophic effects in the Ionian basin, including its deepest parts. Pelagic turbidites of local origin were deposited on the bottom of small perched basins of the Southern Calabrian, Western and Central Mediterranean Ridges (type A homogenite) whereas a megaturbidite of distal origin, presumably triggered by the tsunami wave hitting the shoreline of the Sirte Gulf, was deposited on the Ionian and Sirte Abyssal Plains, extending eastwards as far as the Western Herodotous Trough depositing a thick, acoustically transparent layer (type B homogenite). Three core transects crossing the deformation front of the Mediterranean Ridge are presented and discussed. A fourth transect of giant piston cores was collected on the abyssal plains located to the south of the Mediterranean Ridge. All those to the west of the collision zone contain the Holocene homogenite with a thickness in excess of 20 m, whereas the cores taken from the Herodotous Abyssal Plain east of the collision zone are devoid of the homogenite. Sedimentological analyses were performed on the only giant core that penetrated the sandy base of the homogenite and the underlying pelagic sediments of late Pleistocene (last glacial) age. The African provenance of this typical type B homogenite is corroborated by shallow-water fauna derived from the North African shelf. No sedimentological characteristics peculiar to tsunamiites are observed in the deep-sea homogenite of the eastern Mediterranean.

  16. Triassic magmatism and its relation to decratonization in the eastern North China Craton

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Lithospheric removal and destruction of the North China Craton have been hotly discussed recently. It has been confirmed that the timing of a strong lithospheric removal took place in Late Mesozoic; however, little is known about when the lithospheric removal was initiated and how the Late Permian to Early Triassic deep subduction of Yangtze continental crust affected the cratonic destruction. This paper presents an overview on the temporal and spatial framework and geochemical characteristics of the Triassic intrusive rocks in the eastern North China Craton and use these data to trace their sources and petrogenetic processes, in order to constrain the tectonic setting in which they evolved. It is concluded that the destruction of the North China Craton was initiated in the Late Triassic and induced by delamination of the thickened continental crust by deep subduction of Yangtze continental crust and continent-continent collision. This suggests that the subduction of the continental crust and continent-continent collision are possibly interpreted as the inducement of Late Mesozoic decratonization of the North China Craton.

  17. Triassic magmatism and its relation to decratonization in the eastern North China Craton

    Institute of Scientific and Technical Information of China (English)

    YANG JinHui; WU FuYuan

    2009-01-01

    Lithospheric removal and destruction of the North China Craton have been hotly discussed recently.It has been confirmed that the timing of a strong lithospheric removal took place in Late Mesozoic;however,little is known about when the lithospheric removal was initiated and how the Late Permian to Early Triassic deep subduction of Yangtze continental crust affected the cratonic destruction.This paper presents an overview on the temporal and spatial framework and geochemical characteristics of the Triassic intrusive rocks in the eastern North China Craton and use these data to trace their sources and petrogenetic processes,in order to constrain the tectonic setting in which they evolved.It is concluded that the destruction of the North China Craton was initiated in the Late Triassic and induced by delamination of the thickened continental crust by deep subduction of Yangtze continental crust and continent-continent collision.This suggests that the subduction of the continental crust and continent-continent collision are possibly interpreted as the inducement of Late Mesozoic decratonization of the North China Craton.

  18. Search for Exotic Strange Dibaryon in Relativistic Heavy Ion Collisions

    Institute of Scientific and Technical Information of China (English)

    GAOChong-Shou

    2003-01-01

    The exotic strange dibaryon particle (ΩΩ)0+ with S = -6 can be produced in relativistic heavy ion collisions. The yields of this kind of exotic strange dibaryon particles can increase signitlcantly soon as the formation of QGP does exhibit after the collision. If there is no phase transition after the collision, the upper bound of the production of this diomega can be estimated from the free hadronic gas model for nuclear matter. The relative yield ratio of diomega to deuteron is less than 0.000205, this means that if there is no QGP creation it is difficult to observe the production of diomega in relativistic heavy ion collisions.

  19. A New Aloha Anti-Collision Algorithm Based on CDMA

    Science.gov (United States)

    Bai, Enjian; Feng, Zhu

    The tags' collision is a common problem in RFID (radio frequency identification) system. The problem has affected the integrity of the data transmission during the process of communication in the RFID system. Based on analysis of the existing anti-collision algorithm, a novel anti-collision algorithm is presented. The new algorithm combines the group dynamic frame slotted Aloha algorithm with code division multiple access technology. The algorithm can effectively reduce the collision probability between tags. Under the same number of tags, the algorithm is effective in reducing the reader recognition time and improve overall system throughput rate.

  20. A collision detection approach in virtual environment of micromanipulation robot

    Institute of Scientific and Technical Information of China (English)

    Sun Lining; Tan Fusheng; Rong Weibin; Zhu Jiang

    2005-01-01

    Operators suffer much difficulty in manipulating micro-size objects without the assistance of friendly interfaces due to the scaling effects in micro world. The paper presented a general framework for micromanipulation robot based on virtual reality technology. With the framework we brought forward a FDH (Fixed Direction Hulls) based bounding box method to handle the collision detection of the peg-in-hole microassembly. The collision response model for the collision between micro needle and hole was presented. The virtual force and corresponding displacement were calculated with the model of bending deformation and pressing deformation. Experiments verify the validity of collision response model.

  1. Coulomb-influenced collisions in aerosols and dusty plasmas.

    Science.gov (United States)

    Gopalakrishnan, Ranganathan; Hogan, Christopher J

    2012-02-01

    In aerosol and dusty plasma systems, the behavior of suspended particles (grains) is often strongly influenced by collisions occurring between ions and particles, as well as between particles themselves. In determining the collision kernel or collision rate coefficient for such charged entities, complications arise in that the collision process can be completely described neither by continuum transport mechanics nor by free molecular (ballistic) mechanics; that is, collisions are transition regime processes. Further, both the thermal energy and the potential energy between colliding entities can strongly influence the collision rate and must be considered. Flux-matching theory, originally developed by Fuchs, is frequently applied for calculation of collision rate coefficients under these circumstances. However, recent work suggests that crucial assumptions in flux-matching theory are not appropriate to describe transition regime collisions in the presence of potential interactions. Here, we combine dimensional analysis and mean first passage time calculations to infer the collision kernel between dilute charged entities suspended in a light background gas at thermal equilibrium. The motion of colliding entities is described by a Langevin equation, and Coulombic interactions are considered. It is found that the dimensionless collision kernel for these conditions, H, is a function of the diffusive Knudsen number, Kn(D) (in contrast to the traditional Knudsen number), and the potential energy to thermal energy ratio, Ψ(E). For small and large Kn(D), it is found that the dimensionless collision kernels inferred from mean first passage time calculations collapse to the appropriate continuum and free molecular limiting forms, respectively. Further, for repulsive collisions (Ψ(E) negative) or attractive collisions with Ψ(E)0.5, it is found that flux-matching theory predictions substantially underestimate the collision kernel. We find that the collision process in this

  2. Quark vs Gluon jets in Heavy Ion Collisions

    CERN Document Server

    Drauksas, Simonas

    2017-01-01

    The project concerned quark and gluon jets which are often used as probes of Quantum Chromodynamics(QCD) matter created in nuclear collisions at collider energies. The goal is to look for differences between quark and gluon jets, study their substructure, look for distinguishing features in unquenched (pp collisions) and quenched (heavy ion collisions) jets by using multi-variate analysis which was carried out with the help of ROOT's \\href{https://root.cern.ch/tmva}{TMVA} tool. Mapping out the modification of jets due to medium interactions could give valuable input to constraining the time evolution of the Quark Gluon Plasma created in heavy ion collisions.

  3. Turbulent collision statistics of cloud droplets at low dissipation rates

    Science.gov (United States)

    Banerjee, Sandipan

    Collisions of sedimenting droplets in a turbulent flow is of great importance in cloud physics. Collision efficiency and collision enhancement over gravitational collision by air turbulence govern the growth of the cloud droplets leading to warm rain initiation and precipitation dynamics. In this thesis we present direct numerical simulation (DNS) results for collision statistics of droplets in turbulent flows of low dissipation rates (in the range of 3 cm2/s3-100 cm2/s3) relevant to strato-cumulus clouds. First, we revisit the case of gravitational collision in still fluid to validate the details of the collision detection algorithm used in our code. We compare the collision statistics with either new analytical predictions regarding the percentages of different collision types, or results from published papers. The effect of initial conditions on the collision statistics and statistical uncertainties are analyzed both analytically and through the simulation data. Second, we consider the case of weak turbulence (as in strato-cumulus clouds). In this case the particle motion is mainly driven by gravity. The standard deviation (or the uncertainty) of the average collision statistics is examined analytically in terms of time correlation function of the data. We then report new DNS results of collision statistics in a turbulent flow, showing how air turbulence increases the geometric colli- sion statistics and the collision efficiency. We find that the collision-rate enhancement due to turbulence depends nonlinearly on the flow dissipation rate. This result calls for a more careful parameterization of the collision statistics in strato-cumulus clouds. Due to the low flow dissipation rate in stratocumulus clouds, a related challenge is low droplet Stokes number. Here the Stokes number is the ratio of droplet inertial response time to the flow Kolmogorov time. A very low Stokes number implies that the numerical integration time step is now governed by the droplet

  4. Observation of elastic collisions between lithium atoms and calcium ions

    CERN Document Server

    Haze, Shinsuke; Fujinaga, Munekazu; Mukaiyama, Takashi

    2013-01-01

    We observed elastic collisions between laser-cooled fermionic lithium atoms and calcium ions at the energy range from 100 mK to 3 K. Lithium atoms in an optical-dipole trap were transported to the center of the ion trap using an optical tweezer technique, and a spatial overlap of the atoms and ions was realized in order to observe the atom-ion interactions. The elastic scattering rate was determined from the decay of atoms due to elastic collisions with ions. The collision-energy dependence of the elastic scattering cross-section was consistent with semi-classical collision theory.

  5. Long-range correlations in high multiplicity and collisions

    Indian Academy of Sciences (India)

    Gunther Roland

    2015-05-01

    This review summarizes recent discoveries in high-energy proton+proton and proton+nucleus collisions, with particular attention on the observation of long-range azimuthal correlations in high multiplicity collisions. These correlations, which resemble those seen in ultrarelativistic nucleus–nucleus collisions, provide a unique window into the physics of the very early collision stage in high energy nuclear interactions. Here we present a compilation of the most important experimental results and briefly discuss successes and challenges for a selection of theoretical approaches.

  6. Theoretical study of charge exchange dynamics in He$^+$ + NO collisions

    CERN Document Server

    Bene, E

    2014-01-01

    We investigate the charge transfer mechanism in the collisions of helium ions on nitric oxide using a molecular description framework with consideration of the orientation of the projectile toward the target. The anisotropy of the collision process has been analysed in detail in connection with the non-adiabatic interactions around avoided crossings. Potential energy curves, radial and rotational coupling matrix elements have been determined by means of ab initio quantum chemical methods. The collision dynamics is performed in the [1.-25.] keV collision energy range using a semiclassical approach, and the total electron transfer cross sections are analysed with regard to available experimental data.

  7. Accelerated middle Miocene exhumation of the Talesh Mountains constrained by U-Th/He thermochronometry: Evidence for the Arabia-Eurasia collision in the NW Iranian Plateau

    Science.gov (United States)

    Madanipour, Saeed; Ehlers, Todd A.; Yassaghi, Ali; Enkelmann, Eva

    2017-08-01

    The Talesh Mountains at the NW margin of the Iranian Plateau curve around the southwestern corner of the South Caspian Block and developed in response to the collision of the Arabian-Eurasian Plates. The timing, rates, and regional changes in late Cenozoic deformation of the Talesh Mountains are not fully understood. In this study, we integrate 23 new apatite and zircon bedrock U-Th/He ages and structurally restored geologic cross sections with previously published detrital apatite fission track data to reconstruct the deformation history of the Talesh Mountains. Our results reveal that slow rock exhumation initiated during the late Oligocene ( 27-23 Ma) and then accelerated in the middle Miocene ( 12 Ma). These events resulted in the present-day high-elevation and curved geometry of the mountains. The spatial and temporal distribution of cooling ages suggest that the Oligocene bending of the Talesh Mountains was earlier than in the eastern Alborz, Kopeh Dagh, and central Alborz Mountains that initiated during the late Cenozoic. Late Oligocene and middle Miocene deformation episodes recorded in the Talesh Mountains can be related to the collisional phases of the Arabian and Eurasian Plates. The lower rate of exhumation recorded in the Talesh Mountains occurred during the initial soft collision of the Arabian-Eurasian Plates in the late Oligocene. The accelerated exhumation that occurred during final collision since the middle Miocene resulted from collision of the harder continental margin.

  8. Analysis and Design of Ship Collision Barriers on a Submerged Floating Tunnel subjected to Large Ship Collisions

    OpenAIRE

    Århus, Gisle Hoel

    2016-01-01

    Reinertsen AS is developing a bridge crossing concept to cross the Sognefjord in Norway. The concept consists of floating bridge and submerged tunnel. The submerged tunnel is exposed to ship collisions from passing ship traffic. A protective ship collision barrier is used to protect the exposed part of the submerged tunnel. A design of the collision barrier is proposed. The barrier is made of Aluminium. There are some special considerations one must take into account when using aluminium...

  9. Tertiary stress field evolution in Sistan (Eastern Iran)

    Science.gov (United States)

    Michael, Jentzer; Marc, Fournier; Philippe, Agard; Jafar, Omrani

    2016-04-01

    are presently mechanically coupled and shortened in the Arabia Eurasia collision zone. The counterclockwise rotation of compression, from Miocene to Present, documented everywhere in Iran is probably related to the rotation of the Arabia-Eurasia direction of convergence. However, the amount of rotation is higher in Central Iran than in South Iran, suggesting a progressive mechanical coupling from Miocene to Present. Tirrul, R., Bell, I.R., Griffis, R.J., Camp, V.E., 1983. The Sistan suture zone of eastern Iran. Geol. Soc. America Bull., 94, 134-150. Walker, R., Jackson, J., 2004. Active tectonics and late Cenozoic strain distribution in central and eastern Iran. Tectonics 23, doi:10.1029/2003TC001529 Walker, R.T., 2006 a. A remote sensing study of active folding and faulting in southern Kerman province, S.E. Iran. J. Struct. Geol. 28, 654-668. doi:10.1016/j.jsg.2005.12.014 Walker, R.T., Khatib, M.M., 2006 b. Active faulting in the Birjand region of NE Iran. Tectonics 25, doi:10.1029/2005TC001871

  10. Topographic evolution of a continental indenter: The eastern Southern Alps

    Science.gov (United States)

    Robl, Jörg; Heberer, Bianca; Prasicek, Günther; Neubauer, Franz; Hergarten, Stefan

    2017-04-01

    The topographic evolution of the eastern Southern Alps (ESA) is controlled by the Late Oligocene - Early Miocene indentation of the Adriatic microplate into an overthickened orogenic wedge emplaced on top of the European plate. Rivers follow topographic gradients that evolve during continental collision and in turn incise into bedrock counteracting the formation of topography. In principle, erosional surface processes tend to establish a topographic steady state so that an interpretation of topographic metrics in terms of the latest tectonic history should be straightforward. However, a series of complications impede deciphering the topographic record of the ESA. The Pleistocene glaciations locally excavated alpine valleys and perturbed fluvial drainages. The Late Miocene desiccation of the Mediterranean Sea and the uplift of the northern Molasse Basin led to significant base level changes in the far field of the ESA and the Eastern Alps (EA), respectively. Among this multitude of mechanisms, the processes that dominate the current topographic evolution of the ESA and the ESA-EA drainage divide have not been identified and a number of questions regarding the interaction of crustal deformation, erosion and climate in shaping the present-day topography remain. We demonstrate the expected topographic effects of each mechanism in a 1-dimensional model and compare them with observed channel metrics. Modern uplift rates are largely consistent with long-term exhumation in the ESA and with variations in the normalized steepness index (ksn) indicating a stable uplift and erosion pattern since Miocene times. We find that ksn increases with uplift rate and declines from the indenter tip in the northwest to the foreland basin in the southeast. The number and magnitude of knickpoints and the distortion in longitudinal channel profiles similarly decrease towards the east. Most knickpoints probably evolved during Pleistocene glaciation cycles, but may represent the incrementally

  11. Insights from 3D numerical simulations on the dynamics of the India-Asia collision zone

    Science.gov (United States)

    Pusok, A. E.; Kaus, B.; Popov, A.

    2013-12-01

    The dynamics of the India-Asia collision zone remains one of the most remarkable topics of the current research interest: the transition from subduction to collision and uplift, followed by the rise of the abnormally thick Tibetan plateau, and the deformation at its Eastern and Western syntaxes, are processes still not fully understood. Models that have addressed this topic include wholescale underthrusting of Indian lithospheric mantle under Tibet, distributed homogeneous shortening or the thin-sheet model, slip-line field model for lateral extrusion or lower crustal flow models for the exhumation of the Himalayan units and lateral spreading of the Tibetan plateau. Of these, the thin-sheet model has successfully illustrated some of the basic physics of continental collision and has the advantage of a 3D model being reduced to 2D, but one of its major shortcomings is that it cannot simultaneously represent channel flow and gravitational collapse of the mantle lithosphere, since these mechanisms require the lithosphere to interact with the underlying mantle, or to have a vertically non-homogeneous rheology. As a consequence, 3D models are emerging as powerful tools to understand the dynamics of coupled systems. However, because of yet recent developments and various complexities, the current 3D models simulating the dynamics of continent collision zones have relied on certain explicit assumptions, such as replacing part of the asthenosphere with various types of boundary conditions that mimic the effect of mantle flow, in order to focus on the lithospheric/crustal deformation. Here, we employ the parallel 3D code LaMEM (Lithosphere and Mantle Evolution Model), with a finite difference staggered grid solver, which is capable of simulating lithospheric deformation while simultaneously taking mantle flow and a free surface into account. We present qualitative results on lithospheric and upper-mantle scale simulations in which the Indian lithosphere is subducted and

  12. Oceanic, island arc, and back-arc remnants into eastern Kamchatka accretionary complexes

    Energy Technology Data Exchange (ETDEWEB)

    Fedorchuk, A.V.; Vishnevskaya, V.S.; Izvekov, I.N. (Institute of the Lithosphere, Moscow (USSR))

    1990-06-01

    The Kamchatsky Mts. accretionary complex in the Eastern Kamchatka orogenic belt was studied for identification of the oceanic and suprasubduction components into accretionary wedges. That complex is divided into two tectonic units. The Lower unit is formed sedimentary and tectonic melanges containing arc-related components (Late Senonian volcaniclastics and boninitic gabbro) and oceanic fragments (Fe-Ti-tholeiites, ocean island basalts, and pelagic sediments of Valanginian to Turonian age). The Upper unit consists of ductile deformed oceanic cumulates from troctolites to Fe-Ti-gabbro, 151 to 172 Ma, which are intruded MORB-like diabases with suprasubduction characteristics, 122 to 141 Ma, and are overlain by basalts similar to latter. The Lower and Upper units are separated by a SW-dipping thrust, which is related by an ophiolitoclastic olistostrome of Late Campanian to Early Maestrichtian age. Both units are covered by Paleocene authoclastic deposits. They are all thrusted over the early Neogene island arc complex, 16 to 20 Ma. The Lower unit of the Kamchatsky Mys accretionary complex was originated in a shear zone between a Late Cretaceous island arc and an Early Cretaceous oceanic plate. The Upper unit represents a Jurassic oceanic remnant that formed a basement of Early Cretaceous back-arc or fore-arc basin. Both units were superposed in the latest Cretaceous. The Kamchatsky Mys accretionary complex was emplaced into the Eastern Kamchatka orogenic belt during late Neogene by collision of the early Neogene island arc.

  13. Binary Collision Density in a Non-Ideal Gas as a Function of Particle Density, Collision Diameter, and Temperature

    Science.gov (United States)

    Mohazzabi, Pirooz

    2017-09-01

    Using molecular dynamics simulations, binary collision density in a dense non-ideal gas with Lennard-Jones interactions is investigated. It is shown that the functional form of the dependence of collision density on particle density and collision diameter remains the same as that for an ideal gas. The temperature dependence of the collision density, however, has a very different form at low temperatures, where it decreases as temperature increases. But at higher temperatures the functional form becomes the same as that for an ideal gas.

  14. New collision attacks on SHA-1 based on optimal joint local-collision analysis

    NARCIS (Netherlands)

    Stevens, M.M.J.; Johansson, T.; Nguyen, P.Q.

    2013-01-01

    The main contributions of this paper are two-fold. Firstly, we present a novel direction in the cryptanalysis of the cryptographic hash function {\\SHA}. Our work builds on previous cryptanalytic efforts on {\\SHA} based on combinations of local collisions. Due to dependencies, previous approaches u

  15. Molecular dynamics and binary collision modeling of the primary damage state of collision cascades

    DEFF Research Database (Denmark)

    Heinisch, H.L.; Singh, B.N.

    1992-01-01

    Quantitative information on defect production in cascades in copper obtained from recent molecular dynamics simulations is compared to defect production information determined earlier with a model based on the binary collision approximation (BCA). The total numbers of residual defects, the fracti...

  16. Animation 7 TeV pp collisions from ALICE- 30 March 2010

    CERN Multimedia

    ALICE Outreach

    2010-01-01

    Run 114783. To show what happens during a proton proton collision. Animation from 7 TeV proton proton collisions in the ALICE experiment. Collisions recorded on the first day of the 7 TeV run, 30 March 2010.

  17. General collision branching processes with two parameters

    Institute of Scientific and Technical Information of China (English)

    CHEN AnYue; LI JunPing

    2009-01-01

    A new class of branching models, the general collision branching processes with two parameters, is considered in this paper. For such models, it is necessary to evaluate the absorbing probabilities and mean extinction times for both absorbing states. Regularity and uniqueness criteria are firstly established. Explicit expressions are then obtained for the extinction probability vector, the mean extinction times and the conditional mean extinction times. The explosion behavior of these models is investigated and an explicit expression for mean explosion time is established. The mean global holding time is also obtained. It is revealed that these properties are substantially different between the super-explosive and sub-explosive cases.

  18. Spin Dependent Collision of Ultracold Metastable Atoms

    CERN Document Server

    Uetake, Satoshi; Doyle, John M; Takahashi, Yoshiro

    2015-01-01

    Spin-polarized metastable atoms of ultracold ytterbium are trapped at high density and their inelastic collisional properties are measured. We reveal that in collisions of Yb(3P2) with Yb(1S0) there is relatively weak inelastic loss, but with a significant spin-dependence consistent with Zeeman sublevel changes as being the dominant decay process. This is in strong contrast to our observations of Yb(3P2)-Yb(3P2) collisional loss, which are, at low field, much more rapid and have essentially no spin dependence. Our results give a guideline to use the 3P2 states in many possible applications.

  19. RHIC operation with asymmetric collisions in 2015

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Aschenauer, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Atoian, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brown, K. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Bruno, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Connolly, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ottavio, T. D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Drees, K. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gardner, C. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gu, X. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hayes, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Laster, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Makdisi, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Marr, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Marusic, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Michnoff, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Montag, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Morris, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Narayan, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Nayak, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Nemesure, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pile, P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Poblaguev, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Roser, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schmidke, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Severino, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Shrey, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Smith, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Steski, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tepikian, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trbojevic, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tsoupas, N. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wang, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); White, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Yip, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zaltsman, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zeno, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhang, S. Y. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-08-07

    To study low-x shadowing/saturation physics as well as other nuclear effects [1], [2], proton-gold (p-Au, for 5 weeks) and proton-Aluminum (p-Al, for 2 weeks) collisions were provided for experiments in 2015 at the Relativistic Heavy Ion Collider (RHIC), with polarized proton beam in the Blue ring and Au/Al beam in the Yellow ring. The special features of the asymmetric run in 2015 will be introduced. The operation experience will be reviewed as well in the report.

  20. Inelastic Collision Rates of Trapped Metastable Hydrogen

    CERN Document Server

    Landhuis, D; Moss, S C; Steinberger, Jack; Van't, K M D; Willmann, L; Greytak, T J; Kleppner, D; Landhuis, David; Matos, Lia; Moss, Stephen C.; Steinberger, Julia K.; Vant, Kendra; Willmann, Lorenz; Greytak, Thomas J.; Kleppner, Daniel

    2003-01-01

    We report the first detailed decay studies of trapped metastable (2S) hydrogen. By two-photon excitation of ultracold H samples, we have produced clouds of at least 5x10^7 magnetically trapped 2S atoms at densities greater than 4x10^10 cm^-3 and temperatures below 100 \\muK. We derive experimental values for the total 2S-2S two-body loss rate constant in this temperature regime. Our results are in the range of recent theoretical calculations. We also find experimental upper limits on the rate constant for loss due to inelastic 1S-2S collisions.

  1. Multifragmentation and dynamics in heavy ion collisions

    Indian Academy of Sciences (India)

    R Roy

    2001-07-01

    A midrapidity zone formed in heavy-ion collisions has been investigated through special selections of light particles and intermediate mass fragments detected in the reaction 35Cl on 12C at 43 MeV/nucleon and the reactions 58Ni on 12C, 24Mg, and 197Au at 34.5 MeV/nucleon, and of neutron energy spectra measured in the reaction 35Cl on natTa. Properties of the observables have been examined to characterize the neck-like structure formed between the two reaction partners.

  2. Non abelian hydrodynamics and heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Calzetta, E. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina)

    2014-01-14

    The goal of the relativistic heavy ion collisions (RHIC) program is to create a state of matter where color degrees of freedom are deconfined. The dynamics of matter in this state, in spite of the complexities of quantum chromodynamics, is largely determined by the conservation laws of energy momentum and color currents. Therefore it is possible to describe its main features in hydrodynamic terms, the very short color neutralization time notwithstanding. In this lecture we shall give a simple derivation of the hydrodynamics of a color charged fluid, by generalizing the usual derivation of hydrodynamics from kinetic theory to the non abelian case.

  3. Jets in Heavy Ion Collisions with CMS

    CERN Document Server

    Salur, Sevil

    2016-01-01

    Jet physics in heavy ion collisions is a rich field which has been rapidly evolving since the first observations of medium interactions at RHIC through back-to-back hadron correlations and at LHC via reconstructed jets. In order to completely characterize the final state via jet-medium interactions and distinguish between competing energy loss mechanisms complementary and robust jet observables are investigated. Latest developments of jet finding techniques and their applications to heavy ion environments are discussed with an emphasis given on experimental results from CMS experiment.

  4. Studies of Fluctuation Processes in Nuclear Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Ayik, Sakir [Tennessee Technological Univ., Cookeville, TN (United States). Dept. of Physics

    2016-04-14

    The standard one-body transport approaches have been extensively applied to investigate heavy-ion collision dynamics at low and intermediate energies. At low energies the approach is the mean-field description of the time-dependent Hartree-Fock (TDHF) theory. At intermediate energies the approach is extended by including a collision term, and its application has been carried out mostly in the semi-classical framework of the Boltzmann-Uhling-Uhlenbeck (BUU) model. The standard transport models provide a good understanding of the average properties of the collision dynamics in terms of the effective interactions in both low and intermediate energies. However, the standard models are inadequate for describing the fluctuation dynamics of collective motion at low energies and disassembling of the nuclear system into fragments at intermediate energies resulting from the growth of density fluctuations in the spinodal region. Our tasks have been to improve the standard transport approaches by incorporating fluctuation mechanisms into the description. There are mainly two different mechanisms for fluctuations: (i) Collisional fluctuations generated by binary nucleon collisions, which provide the dominant mechanism at intermediate energies, and (ii) One-body mechanism or mean-field fluctuations, which is the dominant mechanism at low energies. In the first part of our project, the PI extended the standard transport model at intermediate energies by incorporating collisional mechanism according to the “Generalized Langevin Description” of Mori formalism. The PI and his collaborators carried out a number of applications for describing dynamical mechanism of nuclear multi fragmentations, and nuclear collective response in the semi-classical framework of the approach, which is known as the Boltzmann-Langevin model. In the second part of the project, we considered dynamical description at low energies. Because of the effective Pauli blocking, the collisional dissipation and

  5. Collision strengths for transitions in Ni XIX

    Indian Academy of Sciences (India)

    K M Aggarwal; F P Keenan

    2007-08-01

    In this paper we present calculations of electron impact excitation collision strengths for transitions among the 89 fine-structure levels of the 2s22p6, 2s22p53 ℓ, 2s2p63 ℓ, 2s22p54 ℓ, and 2s2p64 ℓ configurations of Ni XIX, for which flexible atomic code (FAC) has been adopted. Comparisons are made with the earlier available results in the literature, and the anomalies observed have been discussed.

  6. Backward charmonium production in $\\pi N$ collisions

    CERN Document Server

    Pire, B; Szymanowski, L

    2016-01-01

    Hard exclusive backward production of a $J/\\psi$ meson in pion-nucleon collisions is studied in the framework of QCD collinear factorization. In this approach, a hard subprocess amplitude responsible for the production of the heavy quark-antiquark pair factorizes from soft hadronic matrix elements, such as the nucleon distribution amplitude and the pion-to-nucleon transition distribution amplitude. We argue that this reaction mechanism dominates the backward kinematical region for the medium energy pion beam at J-Parc.

  7. Sudden Hadronization in Relativistic Nuclear Collisions

    CERN Document Server

    Rafelski, Johann; Rafelski, Johann; Letessier, Jean

    2000-01-01

    We formulate and study the mechanical instability criterion of dense matter fireballs without considering a specific equation of state (EoS). We demonstrate the consistency with the chemical freeze-out of a fireball of matter formed in 158AGeV Pb-Pb collisions. Assuming EoS appropriate for quark-gluon matter, we demonstrate the required deep QGP supercooling prior to sudden hadronization. In a model independent approach, but using results of hadron abundance analysis and lattice QCD, we show that the latent heat of the deconfined phase is bounded from below 0.14GeV/fm^3\\le B.

  8. Physics of Nuclear Collisions at High Energy

    Energy Technology Data Exchange (ETDEWEB)

    Hwa, Rudolph C. [Univ. of Oregon, Eugene, OR (United States)

    2012-05-01

    A wide range of problems has been investigated in the research program during the period of this grant. Although the major effort has been in the subject of heavy-ion collisions, we have also studied problems in biological and other physical systems. The method of analysis used in reducing complex data in multiparticle production to simple descriptions can also be applied to the study of complex systems of very different nature. Phase transition is an important phenomenon in many areas of physics, and for heavy-ion collisions we study the fluctuations of multiplicities at the critical point. Human brain activities as revealed in EEG also involve fluctuations in time series, and we have found that our experience enables us to find the appropriate quantification of the fluctuations in ways that can differentiate stroke and normal subjects. The main topic that characterizes the research at Oregon in heavy-ion collisions is the recombination model for the treatment of the hadronization process. We have avoided the hydrodynamical model partly because there is already a large community engaged in it, but more significantly we have found the assumption of rapid thermalization unconvincing. Recent results in studying LHC physics lead us to provide more evidence that shower partons are very important even at low p_T, but are ignored by hydro. It is not easy to work in an environment where the conventional wisdom regards our approach as being incorrect because it does not adhere to the standard paradigm. But that is just what a vibrant research community needs: unconventional approach may find evidences that can challenge the orthodoxy. An example is the usual belief that elliptic flow in fluid dynamics gives rise to azimuthal anisotropy. We claim that it is only sufficient but not necessary. With more data from LHC and more independent thinkers working on the subject what is sufficient as a theory may turn out to be incorrect in reality. Another area of investigation that

  9. Absorbed Energy in Ship Collisions and Grounding

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Zhang, Shengming

    1998-01-01

    is that the absorbed energy does not depend on the arrangement of the structure, the material properties, and the damage mode.The purpose of the present paper is to establish a new simple relation between the absorbed energy and the destroyed material volume, which can be used as a design tool for analysis of ship......Minorsky's well-known empirical formula, which relates the absorbed energy to the destroyed material volume, has been widely used in analyses of high energy collision and grounding accidents for nearly 40 years. The advantage of the method is its apparent simplcity. Obviously, its drawback...

  10. Two-Dimensional Distributed Velocity Collision Avoidance

    Science.gov (United States)

    2014-02-11

    trigonometry . For convex polygon agents, the tangents are found by iterating over each point, calculating the z-component of the cross product between a...the modifications to the basic VO to favor the source bot’s current velocity (i.e., encourage the bot to change course as little as possible). To...the source agent on a collision course . However, if ignore factors are used, then A2 is more important (i.e., has a lower ignore factor), and so the

  11. Six decades of atomic collisions in solids

    Science.gov (United States)

    Sigmund, Peter

    2017-09-01

    In response to an invitation by the organizers of the 27th international conference on atomic collisions in solids, a brief survey is presented, starting from the roots of the field in the 1950s and 1960s, of some major discoveries, longstanding problems, surprising findings and memorable controversies in topics covered by the conference. Considering the breadth of the field, the selection of topics is necessarily subjective, but with the emphasis on channeling, stopping and sputtering, three topical areas are discussed which have been active from the early 1960s until now.

  12. Dimesoatoms production in high energy collisions

    CERN Document Server

    Afanasyev, L; Voskresenskaya, O

    2016-01-01

    The production of two meson electromagnetic bound states and free meson pairs $\\pi^+\\pi^-$, $K^+K^-$, $\\pi^+ K^{\\mp}$ in relativistic collisions has been considered. It was shown that making use of the exact Coulomb wave function for dimesoatom (DMA) allows one to calculate the yield of any nS state with desired accuracy. The relative probabilities of production of DMA and meson pairs in the free state are estimated. The amplitude of DMA transition from 1S to 2P state, which is essential for the pionium Lamb shift measurements, has been obtained.

  13. Luminosity and Crab Waist Collision Studies

    CERN Document Server

    Wu, Wanwei

    2015-01-01

    In high energy physics, the luminosity is one useful value to characterize the performance of a particle collider. To gain more available data, we need to maximize the luminosity in most collider experiments. With the discussions of tune shift involved the beam dynamics and a recently proposed "crabbed waist" scheme of beam-beam collisions, we present some qualitative analysis to increase the luminosity. In addition, beam-beam tune shifts and luminosities of $e^{+}e^{-}$, $pp$/$p\\bar{p}$, and $\\mu^{+}\\mu^{-}$ colliders are discussed.

  14. Action principle for Coulomb collisions in plasmas

    Science.gov (United States)

    Hirvijoki, Eero

    2016-09-01

    An action principle for Coulomb collisions in plasmas is proposed. Although no natural Lagrangian exists for the Landau-Fokker-Planck equation, an Eulerian variational formulation is found considering the system of partial differential equations that couple the distribution function and the Rosenbluth-MacDonald-Judd potentials. Conservation laws are derived after generalizing the energy-momentum stress tensor for second order Lagrangians and, in the case of a test-particle population in a given plasma background, the action principle is shown to correspond to the Langevin equation for individual particles.

  15. Action principle for Coulomb collisions in plasmas

    CERN Document Server

    Hirvijoki, Eero

    2015-01-01

    In this letter we derive an action principle for Coulomb collisions in plasmas. Although no natural Lagrangian exists for the Landau-Fokker-Planck equation, an Eulerian variational formulation is found considering the system of partial differential equations that couple the distribution function and the Rosenbluth potentials. Exact conservation laws are derived after generalizing the energy-momentum stress tensor for second order Lagrangians and, in the case of a test-particle population in a given plasma background, the action principle is shown to correspond to the Langevin equation for individual particles. Being suitable for discretization, the presented action allows construction of variational integrators. Numerical implementation is left for a future study.

  16. Non abelian hydrodynamics and heavy ion collisions

    CERN Document Server

    Calzetta, Esteban

    2013-01-01

    The goal of the relativistic heavy ion collisions (RHIC) program is to create a state of matter where color degrees of freedom are deconfined. The dynamics of matter in this state, in spite of the complexities of quantum chromodynamics, is largely determined by the conservation laws of energy momentum and color currents. Therefore it is possible to describe its main features in hydrodynamic terms, the very short color neutralization time notwithstanding. In this lecture we shall give a simple derivation of the hydrodynamics of a color charged fluid, by generalizing the usual derivation of hydrodynamics from kinetic theory to the non abelian case.

  17. Understanding collision cascades in molecular solids

    Energy Technology Data Exchange (ETDEWEB)

    Krantzman, Kristin D. E-mail: krantzmank@cofc.edu; Postawa, Zbigniew; Garrison, Barbara J.; Winograd, Nicholas; Stuart, Steven J.; Harrison, Judith A

    2001-06-01

    This paper describes simulations of the sputtering of a molecular solid that uses a reactive potential with both covalent bonding and van der Waals interactions. Recently, the adaptive intermolecular REBO (AIREBO) potential has been developed, which incorporates intermolecular interactions in a manner that maintains the reactivity of the original reactive empirical bond-order (REBO) potential. Preliminary simulations of the keV bombardment of a molecular solid have been performed using the AIREBO potential. Molecules that are initially struck by the bombarding particle break into fragments. The fragments initiate molecular collision cascades leading to the ejection of intact molecules and molecular fragments from the surface.

  18. Helicity separation in Heavy-Ion Collisions

    CERN Document Server

    Baznat, Mircea; Sorin, Alexander; Teryaev, Oleg

    2013-01-01

    We study the P-odd effects related to the vorticity of the medium formed in noncentral heavy ion collisions. Using the kinetic Quark-Gluon Strings Model we perform the numerical simulations of the vorticity and hydrodynamical helicity for the various atomic numbers, energies and centralities. We observed the vortical structures typically occupying the relatively small fraction of the fireball volume. In the course of numerical simulations the noticeable hydrodanamical helicity was observed manifesting the specific mirror behaviour with respect to the reaction plane. The effect is maximal at the NICA and FAIR energy range.

  19. The dynamics of instability in eastern DRC

    Directory of Open Access Journals (Sweden)

    Pierre Jacquemot

    2010-11-01

    Full Text Available The conflict in eastern Congo has been the most deadly one since the second World War, and its social consequences have been disastrous. Solutions to the conflict – which has its roots in politics, in demographics and in economics – must look to the long term.

  20. Eastern's Employee Communication Crisis: A Case Study.

    Science.gov (United States)

    Saunders, Martha

    1988-01-01

    Explores communication behaviors and reactions of employees during crisis periods, using a qualitative case study of Eastern Airlines pilots. Finds that useful theories for crisis communication can be developed only after sufficient inquiry into the communication needs and behaviors of message receivers. (MS)

  1. Juniper for Streambank Stabilization in Eastern Oregon

    Science.gov (United States)

    Guy R. Sheeter; Errol W. Claire

    1989-01-01

    Cut juniper trees (Juniperous osteosperma Hook.) anchored along eroded streambanks proved beneficial in stabilizing 96 percent of the erosion on eight streams evaluated in eastern Oregon over a 14-year-period. Juniper revetment was a successful substitute for costly rock structures on straight or slightly curved banks, but failed when placed on outside curves or when...

  2. Flexural Properties of Eastern Hardwood Pallet Parts

    Science.gov (United States)

    John A. McLeod; Marshall S. White; Paul A. Ifju; Philip A. Araman

    1991-01-01

    Accurate estimates of the flexural properties of pallet parts are critical to the safe, yet efficient, design of wood pallets. To develop more accurate data for hardwood pallet parts, 840 stringers and 2,520 deckboards, representing 14 hardwood species, were sampled from 35 mills distributed throughout the Eastern United States. The parts were sorted by species,...

  3. Reforms in Higher Education Disappoint Eastern Europeans.

    Science.gov (United States)

    Bollag, Burton

    1999-01-01

    Reviews changes in higher education in Eastern Europe since the fall of communism and finds less than expected change, although enrollment has increased and there is minimal government interference. Obstacles to change include lack of quality controls, falling financial support, and emigration of scholars to other countries or business fields. (DB)

  4. Natural regeneration of eastern hemlock: a review

    Science.gov (United States)

    Daniel L. Goerlich; Ralph D. Nyland

    2000-01-01

    Successful regeneration of eastern hemlock involves a complex biophysical process that commonly spans many years. Critical factors include a reliable source of seed, a suitable seedbed, a partially shaded environment, and several years of favorable moisture. Surface scarification appears critical as a means of site preparation. Even then, young hemlocks grow slowly,...

  5. The "New Politics" of EU's Eastern Enlargement

    DEFF Research Database (Denmark)

    Zank, Wolfgang

    The paper gives an overview of EU's eastern enlargement and draws some theoretical conclusions. In particular, it stresses the point that the EU member states in the process of enlargement have entered a phase of "new politics", characterised by multilateralism, conditionality, help and binding a...

  6. Astroparticle physics at the Eastern Colombia region

    Science.gov (United States)

    Asorey, Hernán; Núñez, Luis A.

    2015-12-01

    We present the emerging panorama of Astroparticle Physics at the Eastern Colombia region, and describe several ongoing projects, most of them related to the Latin American Giant Observatory (LAGO) Project. This research work is carried out at the Grupo de Investigaciones en Relatividad y Gravitacin of Universidad Industrial de Santander.

  7. Impact Assessment and Utilization of Eastern Redcedar

    Directory of Open Access Journals (Sweden)

    Difei Zhang

    2010-01-01

    Full Text Available Problem statement: The fast invasion of eastern redcedar (Juniperus virginiana L. has been considered a significant problem to the environment and rural communities. Approach: This study examined the adverse ecological and economic impacts of eastern redcedar and proposed the sustainable development of value-added panel products from such under-utilized invasive species. Also what economic sectors were mostly influenced was examined. Additionally experimental panels were manufactured from low quality eastern redcedar trees. Results: Both physical and mechanical characteristics of experimental panels were found to be satisfactory and comparable to those of typical commercial panels made from other species. It appears that average modulus of elasticity value of the samples with two density levels had 9% higher than that of a typical commercially produced panels. Conclusion: The importance of this study is expansion of the use of low quality eastern redcedar in value-added composite panel manufacture which seems an alternative solution in the development of an environmentally sound and economically effective way to utilize such resource.

  8. Anemia among school children in eastern Nepal.

    Science.gov (United States)

    Khatiwada, Saroj; Gelal, Basanta; Gautam, Sharad; Tamang, Man Kumar; Shakya, Prem Raj; Lamsal, Madhab; Baral, Nirmal

    2015-06-01

    Anemia is one of the most common public health problems in developing countries like Nepal. This study was done to find the prevalence of anemia among the children aged 4-13 years in eastern Nepal. A cross-sectional study was conducted in 2012 in four districts (Morang, Udayapur, Bhojpur and Ilam) of eastern Nepal to find the prevalence of anemia among the school children of eastern Nepal. Children aged 4-13 years were selected randomly from different schools of above districts and 618 venous blood samples were collected. Hemoglobin level was estimated by using cyanmethemoglobin method. The mean hemoglobin level was 12.2 ± 1.82 gm/dl. About 37.9% (n = 234) children were found anemic. Anemia prevalence was 42.4% (n = 78), 31.6% (n = 60), 45.3% (n = 48) and 34.8% (n = 48) among school children of Morang, Udayapur, Bhojpur and Ilam district, respectively. The study finds anemia as a significant health problem among the school children of eastern Nepal.

  9. Commercial Spanish at Eastern Michigan University.

    Science.gov (United States)

    Voght, Geoffrey M.

    The commercial Spanish courses at Eastern Michigan University, examinations in commercial Spanish, and cooperative education exchange programs are described, and the university's new programs that combine the study of foreign language and business are briefly addressed. A six-course sequence offered on the junior, senior, and graduate levels cover…

  10. Eastern forest environmental threat assessment center

    Science.gov (United States)

    Southern Research Station. USDA Forest Service

    2010-01-01

    The Eastern Forest Environmental Threat Assessment Center (EFETAC) provides the latest research and expertise concerning threats to healthy forests – such as insects and disease, wildland loss, invasive species, wildland fire, and climate change – to assist forest landowners, managers and scientists throughout the East. Established in 2005, EFETAC is a joint effort of...

  11. Fragmentation of eastern United States forest types

    Science.gov (United States)

    Kurt H. Riitters; John W. Coulston

    2013-01-01

    Fragmentation is a continuing threat to the sustainability of forests in the Eastern United States, where land use changes supporting a growing human population are the primary driver of forest fragmentation (Stein and others 2009). While once mostly forested, approximately 40 percent of the original forest area has been converted to other land uses, and most of the...

  12. 27 CFR 9.135 - Virginia's Eastern Shore.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Virginia's Eastern Shore... Virginia's Eastern Shore. (a) Name. The name of the viticultural area described in this section is “Virginia's Eastern Shore.” (b) Approved maps. The appropriate maps for determining the boundaries of...

  13. Fire in Eastern North American Oak Ecosystems: Filling the Gaps

    Science.gov (United States)

    Julian (Morgan) Varner; Mary Arthur; Stacy Clark; Daniel C. Dey; Justin Hart; Callie Schweitzer

    2016-01-01

    This special issue of Fire Ecology is focused on the fire ecology of eastern USA oak (Quercus L.) forests, woodlands, and savannas. The papers were presented as part of the Fifth Fire in Eastern Oak Forests Conference in Tuscaloosa, Alabama, USA, in 2015. The topic of fire in eastern oak ecosystems is one that has received insufficient interest from the...

  14. Deformation style and controlling geodynamic processes at the eastern Guadalquivir foreland basin (Southern Spain)

    Science.gov (United States)

    Marín-Lechado, C.; Pedrera, A.; Peláez, J. A.; Ruiz-Constán, A.; González-Ramón, A.; Henares, J.

    2017-06-01

    The tectonic structure of the Guadalquivir foreland basin becomes complex eastward evolving from a single depocenter to a compartmented basin. The deformation pattern within the eastern Guadalquivir foreland basin has been characterized by combining seismic reflection profiles, boreholes, and structural field data to output a 3-D model. High-dipping NNE-SSW to NE-SW trending normal and reverse fault arrays deform the Variscan basement of the basin. These faults generally affect Tortonian sediments, which show syntectonic features sealed by the latest Miocene units. Curved and S-shaped fault traces are abundant and caused by the linkage of nearby fault segments during lateral fault propagation. Preexisting faults were reactivated either as normal or reverse faults depending on their position within the foreland. At Tortonian time, reverse faults deformed the basin forebulge, while normal faults predominated within the backbulge. Along-strike variation of the Betic foreland basin geometry is supported by an increasing mechanical coupling of the two plates (Alborán Domain and Variscan basement) toward the eastern part of the cordillera. Thus, subduction would have progressed in the western Betics, while it would have failed in the eastern one. There, the initially subducted Iberian paleomargin (Nevado-Filábride Complex) was incorporated into the upper plate promoting the transmission of collision-related compressional stresses into the foreland since the middle Miocene. Nowadays, compression is still active and produces low-magnitude earthquakes likely linked to NNE-SSW to NE-SW preexiting faults reactivated with reverse oblique-slip kinematics. Seismicity is mostly concentrated around fault tips that are frequently curved in overstepping zones.

  15. Numerical simulation of GPS observed clockwise rotation around the eastern Himalayan syntax in the Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    CAO dianLing; SHI YaoLin; ZHANG Huai; WANG Hui

    2009-01-01

    From Global Position System (GPS) measurements,there is a clockwise rotation around the eastern Himalayan syntax in the Tibetan Plateau.This phenomenon is difficult to be interpreted by simple two-dimensional modeling from a geodynamic point of view.Because of the extremely thick crust and the lower crust with relatively high temperature in the Tibetan Plateau,the lithospheric rheology in Tibet and surrounding areas present a complex structure,in general,the tectonic structure of the Tibetan Plateau consists of brittle upper crust,ductile lower crust,high viscosity lithospheric upper mantle,and low viscosity asthenosphere,the same as the case in many other continental regions.However,the lower crust in the Tibetan Plateau is much more ductile with a lower viscosity than those of its sur-roundings at the same depth,and the effective viscosity is low along the collision fault zone.In this study,we construct a three-dimensional Maxwell visco-elastic model in spherical coordinate system,and simulate the deformation process of the Tibetan Plateau driven by a continuous push from the Indian plate.The results show that the existence of the soft lower crust under the plateau makes the entire plateau uplift as a whole,and the Himalayas and the eastern Himalayan syntax uplift faster.Since the lower crust of surrounding blocks is harder except in the southeastern corner where the high-temperature material is much softer and forms an exit channel for material transfer,after the whole plateau reaches a certain height,the lower crustal and upper mantle material begins to move eastward or southeastward and drag the upper crust to behave same way.Thus,from the macroscopic point of view,a relative rigid motion of the plateau with a clockwise rotation around the eastern Himalayan syntax is developed.

  16. Paleozoic tectonics in the eastern part of Central Asian Orogenic Belt

    Science.gov (United States)

    Liu, Yongjiang; Li, Weimin; Feng, Zhiqiang; Neubauer, Franz

    2017-04-01

    The Central Asian Orogenic Belt (CAOB) is the largest accretionary orogen in the world, which is responsible for considerable Phanerozoic juvenile crustal growth. The NE China and its adjacent areas compose the eastern segment of the CAOB, which is a key area for providing important evidence of the CAOB evolution and understanding the NE Asian tectonics. The eastern segment of the CAOB is composed tectonically of four micro-blocks and four sutures, i.e. Erguna block (EB), Xing'an block (XB), Songliao-Xilinhot block (SXB), Jiamusi block (JB), Xinlin-Xiguitu suture (XXS), Heihe-Hegenshan suture (HHS), Mudanjiang-Yilan suture (MYS) and Solonker-Xar Moron-Changchun-Yanji suture (SXCYS). The EB and XB were amalgamated by westward subduction, oceanic island accretions and final collision in ca. 500 Ma. The XB and SXB were amalgamated by subduction-related Early Paleozoic marginal arc, Late Paleozoic marginal arc and final collision in the late Early Carboniferous to early Late Carboniferous. The JB probably had been attached to the SXB in the Early Paleozoic, but broken apart from the SXB in the Triassic and collided back in the Jurassic. The closure of Paleo-Asian Ocean had experienced a long continue/episodic subduction-accretion processes on margins of the NCC to the south and the SXB to the north from the Early to Late Paleozoic. The final closure happened along the SXCYS, from west Solonker, Sonid Youqi, Kedanshan (Keshenketengqi), Xar Moron River through Songliao Basin via Kailu, Tongliao, Horqin Zuoyizhongqi, Changchun, to the east Panshi, Huadian, Dunhua, Yanji, with a scissors style closure in time from the Late Permian-Early Triassic in the west to the Late Permian-Middle Triassic in the east. The amalgamated blocks should compose a united micro-continent, named as Jiamusi-Mongolia Block (JMB) after Early Carboniferous, which bounded by Mongo-Okhotsk suture to the northwest, Solonker-Xar Moron-Changchun suture to the south and the eastern margin of JB to the

  17. Phylogeography of Eastern Grey Kangaroos, Macropus giganteus, Suggests a Mesic Refugium in Eastern Australia.

    Directory of Open Access Journals (Sweden)

    Brett A Coghlan

    Full Text Available Phylogeographic studies around the world have identified refugia where fauna were able to persist during unsuitable climatic periods, particularly during times of glaciation. In Australia the effects of Pleistocene climate oscillations on rainforest taxa have been well studied but less is known about the effects on mesic-habitat fauna, such as the eastern grey kangaroo (Macropus giganteus. The eastern grey kangaroo is a large mammal that is common and widespread throughout eastern Australia, preferring dry mesic habitat, rather than rainforest. As pollen evidence suggests that the central-eastern part of Australia (southeast Queensland and northern New South Wales experienced cycles of expansion in mesic habitat with contraction in rainforests, and vice versa during glacial and interglacial periods, respectively, we hypothesise that the distribution of the eastern grey kangaroo was affected by these climate oscillations and may have contracted to mesic habitat refugia. From 375 mitochondrial DNA control region sequences from across the distribution of eastern grey kangaroos we obtained 108 unique haplotypes. Phylogenetic analysis identified two clades in Queensland, one of which is newly identified and restricted to a small coastal region in southern Queensland north of Brisbane, known as the Sunshine Coast. The relatively limited geographic range of this genetically isolated clade suggests the possibility of a mesic habitat refugium forming during rainforest expansion during wetter climate cycles. Other potential, although less likely, reasons for the genetic isolation of the highly distinct clade include geographic barriers, separate northward expansions, and strong local adaptation.

  18. Late Paleogene terrestrial fauna and paleoenvironments in Eastern Anatolia: New insights from the Kağızman-Tuzluca Basin

    Science.gov (United States)

    Métais, Grégoire; Sen, Sevket; Sözeri, Koray; Peigné, Stéphane; Varol, Baki

    2015-08-01

    In Eastern Turkey, relatively little work has been undertaken to characterize the sedimentologic and stratigraphical context of the Kağızman-Tuzluca Basin until now. Extending across the Turkey-Armenian border, this basin documents the syn- and post-collisional evolution of Eastern Anatolia, resulting from the closure of the Neotethyan Seaways and the final collision of the Afro-Arabian and Eurasian plates. From detailed sedimentological and paleontological studies, we propose an interpretation of the lithology and depositional environment of the Late Paleogene Alhan Formation located on the western bank of the Aras River. This sequence of terrestrial clastics rests directly and unconformably onto the ophiolitic mélange, and it documents several depositional sequences deposited in alluvial plain and lacustrine environments. At this stage, the age of the Alhan Formation can only be calibrated by fossil evidence. Several stratigraphic levels yielding fossil data along the section have been identified, but these poor assemblages of fauna and flora hamper extensive comparisons with roughly contemporaneous localities of Central and Southern Asia. Carnivorous and ruminant mammal remains are reported for the first time from the supposed Late Oligocene Güngörmez Formation. The identified fossil mammal taxa reveal biogeographic affinities between Central Anatolia and southern Asia, thus suggesting dispersal between these areas during the Oligocene or earlier. Further studies of the fossil assemblages from the Kağızman-Tuzluca Basin and other basins of Eastern Anatolia and lesser Caucasus regions are needed to better constrain the paleobiogeographic models.

  19. Accelerated Hierarchical Collision Detection for Simulation using CUDA

    DEFF Research Database (Denmark)

    Jørgensen, Jimmy Alison; Fugl, Andreas Rune; Petersen, Henrik Gordon

    2011-01-01

    In this article we present a GPU accelerated, hybrid, narrow phase collision detection algorithm for simulation purposes. The algorithm is based on hierarchical bounding volume tree structures of oriented bounding boxes (OBB) that in the past has shown to be efficient for collision detection. The...

  20. Some Intensive and Extensive Quantities in High-Energy Collisions

    CERN Document Server

    Tawfik, A

    2013-01-01

    We review the evolution of some statistical and thermodynamical quantities measured in difference sizes of high-energy collisions at different energies. We differentiate between intensive and extensive quantities and discuss the importance of their distinguishability in characterizing possible critical phenomena of nuclear collisions at various energies with different initial conditions.

  1. Observation of the Mott effect in heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Gudima, K.; Ploszajczak, M.; Bozek, P.; Danielewicz, P.

    1997-10-01

    The possibility of the observation of the Mott momentum in the distribution of the deuterons produced in the process p + n - d + {gamma} in the first stage of the nuclear collision is presented. The correlation of the hard photon with the deuteron allows to select deuterons produced at the beginning of the collision. (authors).

  2. Collision and recombination driven instabilities in variable charged dusty plasmas

    Indian Academy of Sciences (India)

    S Bal; M Bose

    2013-04-01

    The dust-acoustic instability driven by recombination of electrons and ions on the surface of charged and variably-charged dust grains as well as by collisions in dusty plasmas with significant pressure of background neutrals have been theoretically investigated. The recombination driven instability is shown to be dominant in the long wavelength regime even in the presence of dust-neutral and ion-neutral collisions, while in the shorter wavelength regime, the dust-neutral collision is found to play a major role. In an earlier research work, the dust-neutral collision was neglected in comparison to the effect due to the recombination for estimating the dust-acoustic instability; later the other report shows that the recombination effect is negligible in the presence of dust-neutral collisions. In line of this present situation our investigation revealed that the recombination is more important than dust-neutral collisions in laboratory plasma and fusion plasma, while the dust-neutral collision frequency is dominant in the interstellar plasmas. The effects of ion and dust densities and ion streaming on the recombination and collision driven mode in parameter regimes relevant for many experimental studies on dusty plasmas have also been calculated.

  3. Scheduled Collision Avoidance in wireless sensor network using Zigbee

    DEFF Research Database (Denmark)

    Dnyaneshwar, Mantri; Prasad, Neeli R.; Prasad, Ramjee

    2014-01-01

    . This paper proposes the Schedule based Collision Avoidance (SCA) algorithm for finding the tradeoff between reliability and energy efficiency by fusion of CSMA/CA and TDMA techniques in Zigbee/ IEEE802.15.4. It uses the multi-path data propagation for collision avoidance and effective utilization...

  4. Using Logistic Regression to Identify Risk Factors Causing Rollover Collisions

    Directory of Open Access Journals (Sweden)

    Essam Dabbour

    2012-12-01

    Full Text Available Rollover collisions are among the most serious collisions that usually result in severe injuries or fatalities. In 2009, there were 8,732 fatal rollover collisions in the United States of America that resulted in the death of 9,833 persons. Those numbers represent approximately 28% and 29% of the total numbers of fatal collisions and fatalities, respectively. The main objective of this paper is to examine the impact of different risk factors that may contribute to this type of serious collisions to help develop countermeasures that limit them. To avoid the bias that may be caused by interactions among different drivers, this analysis focuses on rollover related to single-vehicle collisions so that the behavior of the driver of the collided vehicle can be analyzed more effectively. Logistic regression technique is utilized to analyze single-vehicle rollover collisions that occurred on state and interstate highways in the states of Ohio and Washington in 2009. The results obtained from this analysis have the potential to help decision makers identify different strategies to limit the severity of this type of collisions.

  5. Crabbed Waist Collisions in DAFNE and Super-B Design

    Energy Technology Data Exchange (ETDEWEB)

    Raimondi, P.; Alesini, D.; Biagini, M.E.; Biscari, C.; Boni, R.; Boscolo, M.; Bossi, F.; Buonomo, B.; Clozza, A.; Delle Monache, G.O.; Demma, T.; Di Pasquale, E.; Di Pirro, G.; Drago, A.; Gallo, A.; Ghigo, A.; Guiducci, S.; Ligi, C.; Marcellini, F.; Mazzitelli, Giovanni; Milardi, C.; /Frascati /Orsay, LAL /CERN /Rome III U. /Rome U. /Novosibirsk, IYF /KEK, Tsukuba /INFN, Pisa /INFN, Cosenza /SLAC /Frascati

    2011-11-02

    The new idea of increasing the luminosity of a collider with crab waist collisions and first experimental results from the DA{Phi}NE {Phi}-Factory at LNF, Frascati, using this concept are presented. Consequences for the design of future factories will be discussed. An outlook to the performance reach with crab waist collisions is given, with emphasis on future B Factories.

  6. Theoretical Concepts for Ultra-Relativistic Heavy Ion Collisions

    CERN Document Server

    McLerran, Larry

    2009-01-01

    Various forms of matter may be produced in ultra-relativistic heavy ion collisions. These are the Quark Gluon Plasma, the Color Glass Condensate, the Glasma and Quarkyonic Matter. A novel effect that may be associated with topological charge fluctuations is the Chiral Magnetic Effect. I explain these concepts and explain how they may be seen in ultra-relativistic heavy ion collisions.

  7. Bubble chambers in high energy hadron collisions (and vice versa)

    Energy Technology Data Exchange (ETDEWEB)

    Kittel, W. (Dept. Exp. High Energy Physics, Univ. of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands))

    1994-07-01

    The contribution of bubble chambers to the field of high energy hadron collisions during the last 20 years is reviewed and results are compared to those from other types of collisions and to expectations from models based on the quark-parton content of the respective hadrons. ((orig.))

  8. 14 CFR 129.18 - Collision avoidance system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Collision avoidance system. 129.18 Section... § 129.18 Collision avoidance system. Effective January 1, 2005, any airplane you, as a foreign air... Avoidance Systems If you operate in the United States any . . . Then you must operate that airplane with:...

  9. Research on Double Collision Avoidance Mechanism of Ships at Sea

    Directory of Open Access Journals (Sweden)

    XiuYing Bi

    2015-03-01

    Full Text Available When power driven vessels encounter at sea, they need to avoid collision. The definition of right vessel may mislead ships officers think his or her direct navigating has absolute power with this special ship. This paper will define DCPA symbols; give the cause and the method of double collision avoidance mechanism of ships at sea.

  10. Quarkonia at finite temperature in relativistic heavy-ion collisions

    Indian Academy of Sciences (India)

    Saumen Datta

    2015-05-01

    The behaviour of quarkonia in relativistic heavy-ion collisions is reviewed. After a detailed discussion of the current theoretical understanding of quarkonia in a static equilibriated plasma, we discuss quarkonia yield from the fireball created in ultrarelativistic heavy-ion collision experiments. We end with a brief discussion of the experimental results and outlook.

  11. Auto Collision Technician: An Instructional Guide for Teachers.

    Science.gov (United States)

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    This guide is designed to help teachers in auto collision technician programs for grades 11 and 12 teach the critical competencies of the program. The critical competencies covered are the High Priority-Individual (HP-I) competencies in Ohio's Occupational Competency Assessment Profile (OCAP) for Auto Collision Technician. HP-I competencies are…

  12. Cross sections for electron collisions with nitric oxide

    Science.gov (United States)

    Itikawa, Yukikazu

    2016-09-01

    Cross section data are reviewed for electron collisions with nitric oxide. Collision processes considered are total scattering, elastic scattering, momentum transfer, excitations of rotational, vibrational, and electronic states, ionization, and dissociative electron attachment. After a survey of the literature (up to the end of 2015), recommended values of the cross section are determined, as far as possible.

  13. Switching between alternative responses of the lithosphere to continental collision

    NARCIS (Netherlands)

    Baes, M.; Govers, R.; Wortel, R.

    2011-01-01

    We study possible responses to arc–continent or continent–continent collision using numerical models. Our short-term integration models show that the initial stage of deformation following continental collision is governed by the competition between three potential weakness zones: (1) mantle wedge,

  14. 20 years ago: first collisions (at LEP)

    CERN Multimedia

    2009-01-01

    It’s been 20 years since the first electron positron collision at LEP, and I have to confess to a little self-indulgence in my message this week. Back then I was a member of the OPAL collaboration, the first to see collisions at LEP just before midnight on 13 August 1989 and almost exactly one month after the first circulating beam. It was a historic moment, and the atmosphere in the OPAL control room, 100 metres underground, was one of anticipation and excitement. We reported back to the LEP control room, champagne duly arrived, and over the next few hours, all the experiments were recording data. The pilot run was as smooth as it could be, and within weeks we were announcing new physics. It’s interesting to contrast the start-up of LEP with that of the LHC. With the benefit of hindsight, LEP seems to have got going without a hitch, and indeed it was a smooth start. We circulated beam on 14 July, much to the joy of one of our host states, and it was just a month ...

  15. Polarization effects in collisions of. gamma. beams

    Energy Technology Data Exchange (ETDEWEB)

    Ginzburg, I.F.; Kotkin, G.L.; Panfil' , S.L.; Serbo, V.G.

    1983-10-01

    We study polarization effects in collisions of high energy ..gamma.. beams obtained in the Compton scattering of laser light on electrons (according to the scheme of I. F. Ginzburg et al., Preprint 81-50, IYaF SO AN SSSR, Novosibirsk, 1981, and JETP Letters 34, 491 (1982)). For this we determine the Stokes parameters of the ..gamma.. beams xi/sub i/ and xi-tilde/sub j/ and their average values and as functions of the photon energy and polarization of the initial beams. The quantities that are measurable in ..gamma gamma.. collisions are expressed in terms of the average values , which, in general, are not equal to , which complicates the study of polarization phenomena. In particular, not =0, even for unpolarized electron and laser beams. It is shown that in two important limiting cases roughly-equal. Effects due to correlation between the beams are studied.

  16. Polarization effect in the photon beam collisions

    Energy Technology Data Exchange (ETDEWEB)

    Ginzburg, I.F. (AN SSSR, Novosibirsk. Inst. Matematiki); Kotkin, G.L.; Panfil' , S.L.; Serbo, V.G. (Novosibirskij Gosudarstvennyj Univ., USSR)

    1983-10-01

    Polarization effects are investigated for collisions of high-energy ..gamma.. beams produced from the Compton scattering of laser light on electrons. To do this, were obtained Stokes parameters Xisub(i), xisub(j) tilde of the ..gamma..-beams, and their average values (xisub(i)), (xisub(j) tilde), as functions of the photon energies and polarizations of the initial beams. The quantities to be measUred in the ..gamma gamma.. collisions are expressed via the average values (xisub(i)xisub(j) tilde), which are in general different from (Hisub(i))(xisub(j) tilde), the fact making the investigation of the polarization effects more complicated. In particular, (xi/sub 3/xi/sub 3/ tilde-xi/sub 11/ tilde) not equal to 0 even if the electron and the laser beams are not Polarized. It is shown that (xisub(i)xisub(j) tilde) approximately (xisub(i))(xisub(j) tilde) for two important limiting cases. Effects due to a correlation between the beams are considered.

  17. Proton-Nucleus Collisions in the LHC

    CERN Document Server

    Jowett, J M; Baudrenghien, P; Jacquet, D; Lamont, M; Manglunki, D; Redaelli, S; Sapinski, M; Schaumann, M; Solfaroli Camillocci, M; Tomás, R; Uythoven, J; Valuch, D; Versteegen, R; Wenninger, J

    2013-01-01

    Following the high integrated luminosity accumulated in the first two Pb-Pb collision runs in 2010 and 2011, the LHC heavy-ion physics community requested a first run with p-Pb collisions. This almost unprecedented mode of collider operation was not foreseen in the baseline design of the LHC whose two-in-one magnet design imposed equal rigidity and, hence, unequal revolution frequencies, during injection and ramp. Nevertheless, after a successful pilot physics fill in 2012, the LHC provided of p-Pb luminosity per experiment, at an energy of 5.02 TeV per colliding nucleon pair, with several variations of the operating conditions, in early 2013. Together with a companion p-p run at 2.76 TeV, this was the last physics before the present long shutdown. We summarise the beam physics, operational adaptations and strategy that resulted in extremely rapid commissioning. Finally, we give an account of the progress of the run and provide an analysis of the performance.

  18. Damping of forward neutrons in pp collisions

    Science.gov (United States)

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan; Soffer, J.

    2008-07-01

    We calculate absorptive corrections to single pion exchange in the production of leading neutrons in pp collisions. Contrary to the usual procedure of convolving the survival probability with the cross section, we apply corrections to the spin amplitudes. The nonflip amplitude turns out to be much more suppressed by absorption than the spin-flip one. We identify the projectile proton Fock state responsible for the absorptive corrections as a color octet-octet 5-quarks configuration. Calculations within two very different models, color-dipole light-cone description, and in hadronic representation, lead to rather similar absorptive corrections. We found a much stronger damping of leading neutrons than in some of previous estimates. Correspondingly, the cross section is considerably smaller than was measured at ISR. However, comparison with recent measurements by the ZEUS collaboration of neutron production in deep-inelastic scattering provides a strong motivation for challenging the normalization of the ISR data. This conjecture is also supported by preliminary data from the NA49 experiment for neutron production in pp collisions at SPS.

  19. High Gluon Densities in Heavy Ions Collisions

    CERN Document Server

    Blaizot, Jean-Paul

    2016-01-01

    The early stages of heavy ion collisions are dominated by high density systems of gluons that carry each a small fraction $x$ of the momenta of the colliding nucleons. A distinguishing feature of such systems is the phenomenon of "saturation" which tames the expected growth of the gluon density as the energy of the collision increases. The onset of saturation occurs at a particular transverse momentum scale, the "saturation momentum", that emerges dynamically and that marks the onset of non-linear gluon interactions. At high energy, and for large nuclei, the saturation momentum is large compared to the typical hadronic scale, making high density gluons amenable to a description with weak coupling techniques. This paper reviews some of the challenges faced in the study of such dense systems of small $x$ gluons, and of the progress made in addressing them. The focus is on conceptual issues, and the presentation is both pedagogical, and critical. Examples where high gluon density could play a visible role in hea...

  20. Orbital Debris-Debris Collision Avoidance

    CERN Document Server

    Mason, James; Marshall, William; Levit, Creon

    2011-01-01

    We investigate the feasibility of using a medium-powered (5kW) ground-based laser combined with a ground-based telescope to prevent collisions between debris objects in low-Earth orbit (LEO), for which there is no current, effective mitigation strategy. The scheme utilizes photon pressure alone as a means to perturb the orbit of a debris object. Applied over multiple engagements, this alters the debris orbit sufficiently to reduce the risk of an upcoming conjunction. We employ standard assumptions for atmospheric conditions and the resulting beam propagation. Using case studies designed to represent the properties (e.g. area and mass) of the current debris population, we show that one could significantly reduce the risk of more than half of all debris-debris collisions using only one such laser/telescope facility. We speculate on whether this could mitigate the debris fragmentation rate such that it falls below the natural debris re-entry rate due to atmospheric drag, and thus whether continuous long-term ope...

  1. Aerial vehicles collision avoidance using monocular vision

    Science.gov (United States)

    Balashov, Oleg; Muraviev, Vadim; Strotov, Valery

    2016-10-01

    In this paper image-based collision avoidance algorithm that provides detection of nearby aircraft and distance estimation is presented. The approach requires a vision system with a single moving camera and additional information about carrier's speed and orientation from onboard sensors. The main idea is to create a multi-step approach based on a preliminary detection, regions of interest (ROI) selection, contour segmentation, object matching and localization. The proposed algorithm is able to detect small targets but unlike many other approaches is designed to work with large-scale objects as well. To localize aerial vehicle position the system of equations relating object coordinates in space and observed image is solved. The system solution gives the current position and speed of the detected object in space. Using this information distance and time to collision can be estimated. Experimental research on real video sequences and modeled data is performed. Video database contained different types of aerial vehicles: aircrafts, helicopters, and UAVs. The presented algorithm is able to detect aerial vehicles from several kilometers under regular daylight conditions.

  2. Neo-Alpine orogeny: a case study for micro-ocean micro-plate subduction and collision

    Science.gov (United States)

    Kissling, E.; Lippitsch, R.; Regenauer-Lieb, K.; Schmid, S.

    2003-04-01

    In the tectonically complex Alpine region, three different plates (European, Adriatic, and Ligurian) amalgamated when the orogen formed. Knowledge of the actual structure of the lithosphere-asthenosphere system is of great importance for understanding the evolution of this orogen and the interactions between the three lithospheric blocks. In order to illuminate the structure of the uppermost mantle high-resolution teleseismic tomography was performed. At the temporary TRANSALP array, waveforms from teleseismic earthquakes were recorded and by including wave forms registered at permanent regional stations throughout the Alpine region, a high-quality data set of 4200 manually picked P-arrivals from 22 teleseismic events with even azimuthal distribution was compiled. In a previous study, a 3D crustal model was established based on controlled-source seismology data representing the large-scale shallow Alpine structure, which clearly reflects the effects of the Africa-Europe plate collision by crustal indentations. Tests with synthetic data document that the combination of (1) non-linear inversion, (2) high-quality teleseismic data, and (3) usage of an a priori 3D crustal model in assessing incoming teleseismic wave front distortion, does allow for reliably resolving structures of about 60 km minimal length with a velocity variation in the order of +/- 1% in the upper mantle. Tomographic results clearly reveal two separate lithospheric slabs beneath the Alpine orogen. In the western and central Alps, the slab is partly attached to the European lithosphere and dips steeply toward SSW. From beneath the Tauern window on eastward beneath the Eastern Alps (EA), the second slab is attached to the Adriatic lithosphere and gently dips toward NE. Results of numerical dynamic modelling of internal lithosphere structure and slab geometries suggest, that subduction of European oceanic lithosphere continued in the west, while early transpression-collision occurred in the Eastern

  3. Electron loss of fast projectiles in the collisions with molecules

    CERN Document Server

    Matveev, V I; Rakhimov, Kh Yu

    2011-01-01

    The single and multiple electron loss of fast highly charged projectiles in the collisions with neutral molecules are studied within the framework of a nonperturbative approach. The cross sections for single, double, and triple electron losses are calculated for the collision system $Fe^{q+}\\to N_2$ ($q$=24, 25, 26) at the collision energies 10, 100, and 1000 MeV/u. The effects caused by the collision multiplicity and the orientation of the axis of target molecule are treated. It is shown that collision multiplicity effect leads to considerable differences for the cases of perpendicular and parallel orientations of the molecular axes with respect to the direction of the projectile motion, while for chaotic orientation such effect is negligible.

  4. Collision and composite tumors; radiologic and pathologic correlation.

    Science.gov (United States)

    Sung, Calvin T; Shetty, Anup; Menias, Christine O; Houshyar, Roozbeh; Chatterjee, Shreya; Lee, Thomas K; Tung, Paul; Helmy, Mohammed; Lall, Chandana

    2017-06-16

    The terms composite and collision tumors have been used interchangeably throughout radiological literature. Both composite and collision tumors involve two morphologically and immunohistochemically distinct neoplasms coexisting within a single organ. However, collision tumors lack the histological cellular intermingling seen in composite tumors. Composite tumors often arise from a common driver mutation that induces a divergent histology from a common neoplastic source while collision tumors may arise from coincidental neoplastic change. The purpose of this review is to provide an overview of abdominal composite and collision tumors by discussing hallmark radiographic and pathological presentations of rare hepatic, renal, and adrenal case studies. A better understanding of the presentation of each lesion is imperative for proper recognition, diagnosis, and management of these unique tumor presentations.

  5. [Electron transfer, ionization, and excitation in atomic collisions]. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    1992-12-31

    Fundamental processes of electron transfer, ionization, and excitation in ion-atom and ion-ion collisions are studied. Attention is focussed on one- and two-electron systems and, more recently, quasi-one-electron systems whose electron-target-ion core can be accurately modeled by one-electron potentials. The basic computational approaches can then be taken with few, if any, approximations, and the underlying collisional mechanisms can be more clearly revealed. At intermediate collision energies (e.g., proton energies for p-He{sup +} collisions on the order of 100 kilo-electron volts), many electronic states are strongly coupled during the collision, a coupled-state approach, such as a coupled-Sturmian-pseudostate approach, is appropriate. At higher collision energies (million electron-volt energies) the coupling is weaker with, however, many more states being coupled together, so that high-order perturbation theory is essential.

  6. An Investigation of Collisions between Fiber Positioning Units in LAMOST

    CERN Document Server

    Liu, Xiao-Jie

    2015-01-01

    The arrangement of the fiber positioning units in LAMOST focal plane may lead to the collisions during the fiber allocation. To avoid these collisions, the soft protection system has to abandon some targets located in the overlapped field of the adjacent fiber units. In this paper, we firstly analyzed the probability of the collisions between fibers and inferred their possible reasons. It is useful to solve the problem of the fiber-positioning units collisions so as to improve LAMOST efficiency. Based on it, a collision handling system is designed by using the master-slave control structure between the micro control unit (MCU) and the microcomputer. The simulated experiments validate that the system can provide real-time inspection and swap the information between the fiber unit controllers and the main controller.

  7. Initial state fluctuations in collisions between light and heavy ions

    CERN Document Server

    Welsh, Kevin; Heinz, Ulrich W

    2016-01-01

    In high energy collisions involving small nuclei (p+p or x+Au collisions where x=p, d, or $^3$He) the fluctuating size, shape and internal gluonic structure of the nucleon is shown to have a strong effect on the initial size and shape of the fireball of new matter created in the collision. A systematic study of the eccentricity coefficients describing this initial fireball state for several semi-realistic models of nucleon substructure and for several practically relevant collision systems involving small nuclei is presented. The key importance of multiplicity fluctuations in such systems is pointed out. Our results show large differences from expectations based on conventional Glauber model simulations of the initial state created in such collisions.

  8. INTEGRAL COLLISION KERNEL FOR THE GROWTH OF AEROSOL PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Hongyong Xie

    2005-01-01

    Integral collision kernel is elucidated using experimental results for titania, silica and alumina nanoparticles synthesized by FCVD process, and titania submicron particles synthesized in a tube furnace reactor. The integral collision kernel was obtained from a particle number balance equation by the integration of collision rates from the kinetic theory of dilute gases for the free-molecule regime, from the Smoluchowski theory for the continuum regime, and by a semi-empirical interpolation for the transition regime between the two limiting regimes. Comparisons have been made on particle size and the integral collision kernel, showing that the predicted integral collision kernel agreed well with the experimental results in Knudsen number range from about 1.5 to 20.

  9. Detrital zircon U-Pb age and Hf isotopic composition from foreland sediments of the Assam Basin, NE India: Constraints on sediment provenance and tectonics of the Eastern Himalaya

    Science.gov (United States)

    Vadlamani, Ravikant; Wu, Fu-Yuan; Ji, Wei-Qiang

    2015-11-01

    Synorogenic Palaeogene-Neogene sediments of the Assam foreland basin, were derived by erosion of adjacent crustal and orogenic sources following the Greater India-Eurasia collision since ∼55 Ma. To constrain source sediment influx, and its relation to Himalayan tectonics, from pre- to post-collision time, detrital zircon U-Pb geochronology and their Hf isotopic compositions were carried out. The varying detrital zircon spectral patterns analyzed from the Paleogene Jaintia, Barail and Neogene Surma and Tipam Groups, with sediment petrography, track source sediment derived from cratonic India, Gangdese and eastern Transhimalayan batholiths and the eastern Himalaya. These sources are tested against Cenozoic paleopositions proposed for the northeastward motion of the Indian plate. Precollisional cratonic detritus to Middle to Late Eocene Sylhet Formation shifted to Tethyan Himalaya and arc sources of the Gangdese and eastern Transhimalayan batholiths to Late Eocene Kopili and Barail Formations, consistent with the proposed paleoposition proximal to the Indus-Yarlung suture. This Sylhet-Kopili Formation transition, within the Jaintia Group, reflects one of the earliest Himalayan hinterland exhumation stages during the Late Eocene. Major shift in provenance to Higher Himalayan Crystalline and arc detritus is recorded from the Surma Group, constraining Mid Miocene Himalayan tectonic exhumation from the eastern Himalaya. Late Miocene Tipam Group preserves sediment of Higher Himalayan Crystalline detritus, ophiolite and likely Lesser Himalayan rocks.

  10. Tectonic setting of Cretaceous basins on the NE Tibetan Plateau: Insights from the Jungong basin

    Science.gov (United States)

    Craddock, W.H.; Kirby, E.; Dewen, Z.; Jianhui, L.

    2012-01-01

    Quantifying the Cenozoic growth of high topography in the Indo-Asian collision zone remains challenging, due in part to significant shortening that occurred within Eurasia before collision. A growing body of evidence suggests that regions far removed from the suture zone experienced deformation before and during the early phases of Himalayan orogenesis. In the present-day north-eastern Tibetan Plateau, widespread deposits of Cretaceous sediment attest to significant basin formation; however, the tectonic setting of these basins remains enigmatic. We present a study of a regionally extensive network of sedimentary basins that are spatially associated with a system of SE-vergent thrust faults and are now exposed in the high ranges of the north-eastern corner of the Tibetan Plateau. We focus on a particularly well-exposed basin, located ~20km north of the Kunlun fault in the Anyemaqen Shan. The basin is filled by ~900m of alluvial sediments that become finer-grained away from the basin-bounding fault. Additionally, beds in the proximal footwall of the basin-bounding fault exhibit progressive, up-section shallowing and several intraformational unconformities which can be traced into correlative conformities in the distal part of the basin. The observations show sediment accumulated in the basin during fault motion. Regional constraints on the timing of sediment deposition are provided by both fossil assemblages from the Early Cretaceous, and by K-Ar dating of volcanic rocks that floor and cross-cut sedimentary fill. We argue that during the Cretaceous, the interior NE Tibetan Plateau experienced NW-SE contractional deformation similar to that documented throughout the Qinling-Dabie orogen to the east. The Songpan-Ganzi terrane apparently marked the southern limit of this deformation, such that it may have been a relatively rigid block in the Tibetan lithosphere, separating regions experiencing deformation north of the convergent Tethyan margin from regions deforming

  11. Real-time collision avoidance in space: the GETEX experiment

    Science.gov (United States)

    Freund, Eckhard; Rossmann, Juergen; Schluse, Michael

    2000-10-01

    Intelligent autonomous robotic systems require efficient safety components to assure system reliability during the entire operation. Especially if commanded over long distances, the robotic system must be able to guarantee the planning of safe and collision free movements independently. Therefore the IRF developed a new collision avoidance methodology satisfying the needs of autonomous safety systems considering the dynamics of the robots to protect. To do this, the collision avoidance system cyclically calculates the actual collision danger of the robots with respect to all static and dynamic obstacles in the environment. If a robot gets in collision danger the methodology immediately starts an evasive action to avoid the collision and guides the robot around the obstacle to its target position. This evasive action is calculated in real-time in a mathematically exact way by solving a quadratic convex optimization problem. The secondary conditions of this optimization problem include the potential collision danger of the robots kinematic chain including all temporarily attached grippers and objects and the dynamic constraints of the robots. The result of the optimization procedure are joint accelerations to apply to prevent the robot from colliding and to guide it to its target position. This methodology has been tested very successfully during the Japanese/German space robot project GETEX in April 1999. During the mission, the collision avoidance system successfully protected the free flying Japanese robot ERA on board the satellite ETS-VII at all times. The experiments showed, that the developed system is fully capable of ensuring the safety of such autonomous robotic systems by actively preventing collisions and generating evasive actions in cases of collision danger.

  12. Collisions of Dark Matter Axion Stars with Astrophysical Sources

    Energy Technology Data Exchange (ETDEWEB)

    Eby, Joshua [Fermilab; Leembruggen, Madelyn [Cincinnati U.; Leeney, Joseph [Cincinnati U.; Suranyi, Peter [Cincinnati U.; Wijewardhana, L. C.R. [Cincinnati U.

    2017-01-05

    If QCD axions form a large fraction of the total mass of dark matter, then axion stars could be very abundant in galaxies. As a result, collisions with each other, and with other astrophysical bodies, can occur. We calculate the rate and analyze the consequences of three classes of collisions, those occurring between a dilute axion star and: another dilute axion star, an ordinary star, or a neutron star. In all cases we attempt to quantify the most important astrophysical uncertainties; we also pay particular attention to scenarios in which collisions lead to collapse of otherwise stable axion stars, and possible subsequent decay through number changing interactions. Collisions between two axion stars can occur with a high total rate, but the low relative velocity required for collapse to occur leads to a very low total rate of collapses. On the other hand, collisions between an axion star and an ordinary star have a large rate, $\\Gamma_\\odot \\sim 3000$ collisions/year/galaxy, and for sufficiently heavy axion stars, it is plausible that most or all such collisions lead to collapse. We identify in this case a parameter space which has a stable region and a region in which collision triggers collapse, which depend on the axion number ($N$) in the axion star, and a ratio of mass to radius cubed characterizing the ordinary star ($M_s/R_s^3$). Finally, we revisit the calculation of collision rates between axion stars and neutron stars, improving on previous estimates by taking cylindrical symmetry of the neutron star distribution into account. Collapse and subsequent decay through collision processes, if occurring with a significant rate, can affect dark matter phenomenology and the axion star mass distribution.

  13. Geocoding police collision report data from California: a comprehensive approach

    Directory of Open Access Journals (Sweden)

    Park Shin

    2009-12-01

    Full Text Available Abstract Background Collision geocoding is the process of assigning geographic descriptors, usually latitude and longitude coordinates, to a traffic collision record. On California police reports, relative collision location is recorded using a highway postmile marker or a street intersection. The objective of this study was to create a geocoded database of all police-reported, fatal and severe injury collisions in the California Statewide Integrated Traffic Records System (SWITRS for years 1997-2006 for use by public agencies. Results Geocoding was completed with a multi-step process. First, pre-processing was performed using a scripting language to clean and standardize street name information. A state highway network with postmile values was then created using a custom tool written in Visual Basic for Applications (VBA in ArcGIS software. Custom VBA functionality was also used to incorporate the offset direction and distance. Intersection and address geocoding was performed using ArcGIS, StreetMap Pro 2003 digital street network, and Google Earth Pro. A total of 142,007 fatal and severe injury collisions were identified in SWITRS. The geocoding match rate was 99.8% for postmile-coded collisions and 86% for intersection-coded collisions. The overall match rate was 91%. Conclusions The availability of geocoded collision data will be beneficial to clinicians, researchers, policymakers, and practitioners in the fields of traffic safety and public health. Potential uses of the data include studies of collision clustering on the highway system, examinations of the associations between collision occurrence and a variety of variables on environmental and social characteristics, including housing and personal demographics, alcohol outlets, schools, and parks. The ability to build maps may be useful in research planning and conduct and in the delivery of information to both technical and non-technical audiences.

  14. Sensor management for collision alert in orbital object tracking

    Science.gov (United States)

    Xu, Peiran; Chen, Huimin; Charalampidis, D.; Shen, Dan; Chen, Genshe; Blasch, Erik; Pham, Khanh

    2011-06-01

    Given the increasingly dense environment in both low-earth orbit (LEO) and geostationary orbit (GEO), a sudden change in the trajectory of any existing resident space object (RSO) may cause potential collision damage to space assets. With a constellation of electro-optical/infrared (EO/IR) sensor platforms and ground radar surveillance systems, it is important to design optimal estimation algorithms for updating nonlinear object states and allocating sensing resources to effectively avoid collisions among many RSOs. Previous work on RSO collision avoidance often assumes that the maneuver onset time or maneuver motion of the space object is random and the sensor management approach is designed to achieve efficient average coverage of the RSOs. Few attempts have included the inference of an object's intent in the response to an RSO's orbital change. We propose a game theoretic model for sensor selection and assume the worst case intentional collision of an object's orbital change. The intentional collision results from maximal exposure of an RSO's path. The resulting sensor management scheme achieves robust and realistic collision assessment, alerts the impending collisions, and identifies early RSO orbital change with lethal maneuvers. We also consider information sharing among distributed sensors for collision alert and an object's intent identification when an orbital change has been declared. We compare our scheme with the conventional (non-game based) sensor management (SM) scheme using a LEO-to-LEO space surveillance scenario where both the observers and the unannounced and unplanned objects have complete information on the constellation of vulnerable assets. We demonstrate that, with adequate information sharing, the distributed SM method can achieve the performance close to that of centralized SM in identifying unannounced objects and making early warnings to the RSO for potential collision to ensure a proper selection of collision avoidance action.

  15. Decadal variability in the Eastern North Atlantic

    Science.gov (United States)

    Köllner, Manuela; Klein, Birgit; Kieke, Dagmar; Klein, Holger; Rhein, Monika; Roessler, Achim; Denker, Claudia

    2016-04-01

    The strong warming and salinification of the Eastern North Atlantic starting in the mid 1990s has been attributed to a westward contraction of the subpolar gyre and stronger inflow of waters from the subtropical gyre. Temporal changes in the shape and strength of the two gyres have been related to the major mode of atmospheric variability in the Atlantic sector, the NAO. Hydrographic conditions along the Northwest European shelf are thus the result of different processes such as variations in transports, varying relative contributions of water masses from the two gyres and property trends in the source water masses. We examine the decadal variability in the eastern North Atlantic based on Argo data from 2000-2015 and have constructed time series for four water masses (Subpolar Mode Water (SPMW), Intermediate Water (IW), upper Labrador Sea Water (uLSW) and deep Labrador Sea Water (dLSW)) at selected locations along the Northwest European shelf. Data from the Rockall Trough and the Iceland Basin are chosen to represent advective pathways in the subpolar gyre at two major branches of the North Atlantic Current towards the Nordic Seas and the Arctic Ocean. Temporal variability of subtropical waters transported northward along the eastern boundary is studied at Goban Spur around 48°N. The Argo data are extended in time with long-term hydrographic observations such as the Extended Ellet Line data and other climatological sources in the region. For the study of transport fluctuations time series from the RACE (Regional circulation and Global change) program (2012-2015) and predecessor programs have been used. These programs have monitored the subpolar gyre in the western basin and provide time series of transports and hydrographic anomalies from moored instruments at the western flank of the Mid Atlantic Ridge (MAR). First results show that the temperatures and salinities remained at high levels for the upper waters (SPMW and IW) until 2010 and have been decreasing since

  16. Prevalence of blood parasites in eastern versus Western house finches: are eastern birds resistant to infection?

    Science.gov (United States)

    Davis, Andrew K; Hood, Wendy R; Hill, Geoffrey E

    2013-09-01

    The rapid spread of the bacterial disease, Mycoplasma gallisepticum (MG), throughout the introduced range of house finches (Carpodacus mexicanus) in eastern North America, compared to its slower spread through the native western range, has puzzled researchers and highlights the need to understand the relative differences in health state of finches from both populations. We conducted a light-microscope survey of hemoparasites in populations of finches from Arizona (within the western range) and from Alabama (within the eastern range), and compared our estimates of prevalence to published reports from house finches sampled in both ranges. Of the 33 Arizona birds examined, we recorded hematozoan infections in 16 (48.5%) individuals, compared to 1 infected Alabama bird out of 30 birds examined (3.3%). Based on independent surveys of seven western North American and five eastern North American populations of house finches the average prevalence of blood parasites in western populations is 38.8% (±17.9 SD), while the average prevalence within the eastern range is only 5.9% (±6.1 SD). The average rate of infection among all songbirds sampled in the east is 34.2% (±4.8 SD). Thus, our surveys of wild birds as well as previously published observations point to eastern house finches having a much lower prevalence of blood parasite infections than their western counterparts. Combined with the fact that eastern finches also tend to have lower rates of avian pox infections than do western birds (based on a literature review), these observations suggest that eastern birds have either strong resistance to these infections or high susceptibility and associated mortality.

  17. Wounded nucleon model with realistic nucleon-nucleon collision profile and observables in relativistic heavy-ion collisions

    CERN Document Server

    Rybczyński, Maciej

    2011-01-01

    We investigate the influence of the nucleon-nucleon collision profile (probability of interaction as a function of the nucleon-nucleon impact parameter) in the wounded nucleon model and its extensions on several observables measured in relativistic heavy-ion collisions. We find that the participant eccentricity coefficient, $\\epsilon^\\ast$, as well as the higher harmonic coefficients, $\\epsilon_n^\\ast$, are reduced by 10-20% for mid-peripheral collisions when the realistic (Gaussian) profile is used, as compared to the case with the commonly-used hard-sphere profile. Similarly, the multiplicity fluctuations, treated as the function of the number of wounded nucleons in one of the colliding nuclei, are reduced by 10-20%. This demonstrates that the Glauber Monte Carlo codes should necessarily use the realistic nucleon-nucleon collision profile in precision studies of these observables. The Gaussian collision profile is built-in in {\\tt GLISSANDO}.

  18. Cenozoic metamorphism along the Shan Scarp (Myanmar): Evidences for ductile shear along the Sagaing Fault or the northward migration of the Eastern Himalayan Syntaxis?

    Science.gov (United States)

    Bertrand, Guillaume; Rangin, Claude; Maluski, Henri; Han, Tin Aung; Thein, Myint; Myint, Ohn; Maw, Win; Lwin, San

    The Mogok metamorphic belt, exposed along the N-S trending Shan scarp and Sagaing fault, in the eastern part of Myanmar, has been regarded as Paleozoic to Precambrian for a long time. New observations in the Shan scarp area, close to the Sagaing fault, from Thaton in the south to Mandalay in the north, allowed us to collect samples of high grade metamorphic and intrusive rocks that have been analyzed by 40Ar/39Ar step heating method. The 13 samples we analyzed provide Oligocene to Lower Miocene ages for this metamorphism. Oriented thin sections and field observations suggest that this metamorphism was caused by a NNW-SSE to N-S ductile extension. Therefore, we suggest that this metamorphism is not directly related to the Sagaing fault, but could be instead related to the northward migration of the eastern Himalayan syntaxis, characterized by crustal thinning, resulting from the India-Asia oblique collision.

  19. The collision that changed the world

    Directory of Open Access Journals (Sweden)

    Wally Broecker

    2015-07-01

    Full Text Available Abstract In connection with the Anthropocene, one might ask how climate is likely to evolve in the absence of man’s intervention and whether humans will be able to purposefully alter this course. In this commentary, I deal with the situation for very long time scales. I make a case that fifty million years ago, the collision between the northward drifting Indian land mass and Asia set the Earth’s climate on a new course. Ever since then, it has cooled. In the absence of some other dramatic disruption in the movement of the plates which make up our planet’s crust, on the time scale of tens of millions of years, this drift would cause the Earth to freeze over as it did during the late Precambrian. Evidence for this change in course comes from records of oxygen and lithium isotopic composition of foraminifer shells. It is reinforced by records of Mg to Ca in halite-hosted fluid inclusions and in marine CaCO3. In addition, the collision appears to have created abrupt changes in the sulfur isotope composition of marine barite and the carbon isotope composition of amber. Not only did this collision create the Himalaya, but more important, it led to a reorganization of the crustal plate motions. Through some combination of the building of mountains and lowering of sea level, these changes generated a mismatch between the supply of CO2 by planetary outgassing and that of calcium by the weathering of silicate rock. The tendency toward an oversupply of calcium has been compensated by a drawdown of the atmosphere’s CO2 content. This drawdown cooled the Earth, slowing down the supply of calcium. Although we are currently inadvertently compensating for this cooling by burning fossil fuels, the impacts of this CO2 on Earth climate will last no more than a tenth of a million years. So, if humans succeed in avoiding extinction, there will likely be a long-term effort to warm the planet.

  20. Dielectron production in proton-proton collisions with ALICE

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, Markus Konrad

    2015-10-01

    Ultrarelativistic hadron collisions, such as delivered since a couple of years at the Large Hadron Collider (LHC), provide new insights into the properties of strongly interacting matter at high temperatures and densities, which is expected to have existed a few of a millionth seconds after the big bang. Electromagnetic probes, such as leptons and photons, are emitted during the entire collision. Since they do not undergo strong interactions, they reflect the entire evolution of the collision. Pairs of leptons, so called dileptons, have the advantage compared to real photons, that they do not only carry momentum, but also have a non-zero invariant mass. The invariant mass spectrum of dileptons is a superposition of several components and allows to address different characteristics of the medium. To understand dielectron production in heavy-ion collisions, reference measurements in proton-proton (pp) collisions are necessary. pp collisions reflect the vacuum contribution of the particles produced in heavy-ion collisions. The analysis of pp collisions is an essential step towards the extraction of medium influences on the vector meson spectral functions and the thermal radiation in heavy-ion collisions. In this thesis, the production of electron-positron pairs (dielectrons) in pp collisions at a collision energy of 7 TeV in the ALICE central barrel is analysed. ALICE has unique particle identification capabilities at low momentum. Electrons and positrons are identified with a high purity and combined to pairs. The invariant mass distribution of dielectrons is corrected for detector effects and the selection criteria in the analysis with Monte Carlo simulations. The dielectron invariant mass spectrum of known hadronic sources is calculated based on the cross sections measured in other decay channels using the known decay kinematics. This so called hadronic cocktail represents the dielectron spectrum at the moment of kinematic freeze-out and can be compared to the