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Sample records for auroras glow regulation

  1. Aurora-A regulates MCRS1 function during mitosis.

    Science.gov (United States)

    Meunier, Sylvain; Timón, Krystal; Vernos, Isabelle

    2016-07-02

    The mitotic spindle is made of microtubules (MTs) nucleated through different pathways involving the centrosomes, the chromosomes or the walls of pre-existing MTs. MCRS1 is a RanGTP target that specifically associates with the chromosome-driven MTs protecting them from MT depolymerases. MCRS1 is also needed for the control of kinetochore fiber (K-fiber) MT minus-ends dynamics in metaphase. Here, we investigated the regulation of MCRS1 activity in M-phase. We show that MCRS1 is phosphorylated by the Aurora-A kinase in mitosis on Ser35/36. Although this phosphorylation has no role on MCRS1 localization to chromosomal MTs and K-fiber minus-ends, we show that it regulates MCRS1 activity in mitosis. We conclude that Aurora-A activity is particularly important in the tuning of K-fiber minus-ends dynamics in mitosis.

  2. Akt Inhibitor A-443654 Interferes with Mitotic Progression by Regulating Aurora A Kinase Expression

    Directory of Open Access Journals (Sweden)

    Xuesong Liu

    2008-08-01

    Full Text Available Both Akt and Aurora A kinase have been shown to be important targets for intervention for cancer therapy. We report here that Compound A (A-443654, a specific Akt inhibitor, interferes with mitotic progression and bipolar spindle formation. Compound A induces G2/M accumulation, defects in centrosome separation, and formation of either monopolar arrays or disorganized spindles. On the basis of gene expression array studies, we identified Aurora A as one of the genes regulated transcriptionally by Akt inhibitors including Compound A. Inhibition of the phosphatidylinositol 3-kinase (PI3K/Akt pathway, either by PI3K inhibitor LY294002 or by Compound A, dramatically inhibits the promoter activity of Aurora A, whereas the mammalian target of rapamycin inhibitor has little effect, suggesting that Akt might be responsible for up-regulating Aurora A for mitotic progression. Further analysis of the Aurora A promoter region indicates that the Ets element but not the Sp1 element is required for Compound A-sensitive transcriptional control of Aurora A. Overexpression of Aurora A in cells treated with Compound A attenuates the mitotic arrest and the defects in bipolar spindle formation induced by Akt inhibition. Our studies suggest that that Akt may promote mitotic progression through the transcriptional regulation of Aurora A.

  3. Interdomain allosteric regulation of Polo kinase by Aurora B and Map205 is required for cytokinesis

    Science.gov (United States)

    Kachaner, David; Pinson, Xavier; El Kadhi, Khaled Ben; Normandin, Karine; Talje, Lama; Lavoie, Hugo; Lépine, Guillaume; Carréno, Sébastien; Kwok, Benjamin H.; Hickson, Gilles R.

    2014-01-01

    Drosophila melanogaster Polo and its human orthologue Polo-like kinase 1 fulfill essential roles during cell division. Members of the Polo-like kinase (Plk) family contain an N-terminal kinase domain (KD) and a C-terminal Polo-Box domain (PBD), which mediates protein interactions. How Plks are regulated in cytokinesis is poorly understood. Here we show that phosphorylation of Polo by Aurora B is required for cytokinesis. This phosphorylation in the activation loop of the KD promotes the dissociation of Polo from the PBD-bound microtubule-associated protein Map205, which acts as an allosteric inhibitor of Polo kinase activity. This mechanism allows the release of active Polo from microtubules of the central spindle and its recruitment to the site of cytokinesis. Failure in Polo phosphorylation results in both early and late cytokinesis defects. Importantly, the antagonistic regulation of Polo by Aurora B and Map205 in cytokinesis reveals that interdomain allosteric mechanisms can play important roles in controlling the cellular functions of Plks. PMID:25332165

  4. Ndel1 suppresses ciliogenesis in proliferating cells by regulating the trichoplein-Aurora A pathway.

    Science.gov (United States)

    Inaba, Hironori; Goto, Hidemasa; Kasahara, Kousuke; Kumamoto, Kanako; Yonemura, Shigenobu; Inoko, Akihito; Yamano, Shotaro; Wanibuchi, Hideki; He, Dongwei; Goshima, Naoki; Kiyono, Tohru; Hirotsune, Shinji; Inagaki, Masaki

    2016-02-15

    Primary cilia protrude from the surface of quiescent cells and disassemble at cell cycle reentry. We previously showed that ciliary reassembly is suppressed by trichoplein-mediated Aurora A activation pathway in growing cells. Here, we report that Ndel1, a well-known modulator of dynein activity, localizes at the subdistal appendage of the mother centriole, which nucleates a primary cilium. In the presence of serum, Ndel1 depletion reduces trichoplein at the mother centriole and induces unscheduled primary cilia formation, which is reverted by forced trichoplein expression or coknockdown of KCTD17 (an E3 ligase component protein for trichoplein). Serum starvation induced transient Ndel1 degradation, subsequent to the disappearance of trichoplein at the mother centriole. Forced expression of Ndel1 suppressed trichoplein degradation and axonemal microtubule extension during ciliogenesis, similar to trichoplein induction or KCTD17 knockdown. Most importantly, the proportion of ciliated and quiescent cells was increased in the kidney tubular epithelia of newborn Ndel1-hypomorphic mice. Thus, Ndel1 acts as a novel upstream regulator of the trichoplein-Aurora A pathway to inhibit primary cilia assembly. © 2016 Inaba et al.

  5. The Aurora A-HP1γ pathway regulates gene expression and mitosis in cells from the sperm lineage.

    Science.gov (United States)

    Leonard, Phoebe H; Grzenda, Adrienne; Mathison, Angela; Morbeck, Dean E; Fredrickson, Jolene R; de Assuncao, Thiago M; Christensen, Trace; Salisbury, Jeffrey; Calvo, Ezequiel; Iovanna, Juan; Coddington, Charles C; Urrutia, Raul; Lomberk, Gwen

    2015-05-29

    HP1γ, a well-known regulator of gene expression, has been recently identified to be a target of Aurora A, a mitotic kinase which is important for both gametogenesis and embryogenesis. The purpose of this study was to define whether the Aurora A-HP1γ pathway supports cell division of gametes and/or early embryos, using western blot, immunofluorescence, immunohistochemistry, electron microscopy, shRNA-based knockdown, site-directed mutagenesis, and Affymetrix-based genome-wide expression profiles. We find that the form of HP1γ phosphorylated by Aurora A, P-Ser83 HP1γ, is a passenger protein, which localizes to the spermatozoa centriole and axoneme. In addition, disruption in this pathway causes centrosomal abnormalities and aberrations in cell division. Expression profiling of male germ cell lines demonstrates that HP1γ phosphorylation is critical for the regulation of mitosis-associated gene expression networks. In female gametes, we observe that P-Ser83-HP1γ is not present in meiotic centrosomes of M2 oocytes, but after syngamy, it becomes detectable during cleavage divisions, coinciding with early embryonic genome activation. These results support the idea that phosphorylation of HP1γ by Aurora A plays a role in the regulation of gene expression and mitotic cell division in cells from the sperm lineage and in early embryos. Combined, this data is relevant to better understanding the function of HP1γ in reproductive biology.

  6. The mitosis-regulating and protein-protein interaction activities of astrin are controlled by aurora-A-induced phosphorylation.

    Science.gov (United States)

    Chiu, Shao-Chih; Chen, Jo-Mei Maureen; Wei, Tong-You Wade; Cheng, Tai-Shan; Wang, Ya-Hui Candice; Ku, Chia-Feng; Lian, Chiao-Hsuan; Liu, Chun-Chih Jared; Kuo, Yi-Chun; Yu, Chang-Tze Ricky

    2014-09-01

    Cells display dramatic morphological changes in mitosis, where numerous factors form regulatory networks to orchestrate the complicated process, resulting in extreme fidelity of the segregation of duplicated chromosomes into two daughter cells. Astrin regulates several aspects of mitosis, such as maintaining the cohesion of sister chromatids by inactivating Separase and stabilizing spindle, aligning and segregating chromosomes, and silencing spindle assembly checkpoint by interacting with Src kinase-associated phosphoprotein (SKAP) and cytoplasmic linker-associated protein-1α (CLASP-1α). To understand how Astrin is regulated in mitosis, we report here that Astrin acts as a mitotic phosphoprotein, and Aurora-A phosphorylates Astrin at Ser(115). The phosphorylation-deficient mutant Astrin S115A abnormally activates spindle assembly checkpoint and delays mitosis progression, decreases spindle stability, and induces chromosome misalignment. Mechanistic analyses reveal that Astrin phosphorylation mimicking mutant S115D, instead of S115A, binds and induces ubiquitination and degradation of securin, which sequentially activates Separase, an enzyme required for the separation of sister chromatids. Moreover, S115A fails to bind mitosis regulators, including SKAP and CLASP-1α, which results in the mitotic defects observed in Astrin S115A-transfected cells. In conclusion, Aurora-A phosphorylates Astrin and guides the binding of Astrin to its cellular partners, which ensures proper progression of mitosis. Copyright © 2014 the American Physiological Society.

  7. Haspin kinase regulates microtubule-organizing center clustering and stability through Aurora kinase C in mouse oocytes

    Czech Academy of Sciences Publication Activity Database

    Balboula, A. Z.; Nguyen, A. L.; Gentilello, A. S.; Quartuccio, S. M.; Drutovič, Dávid; Šolc, Petr; Schindler, K.

    2016-01-01

    Roč. 129, č. 19 (2016), s. 3648-3660 ISSN 0021-9533 R&D Projects: GA MŠk(CZ) LO1609 Institutional support: RVO:67985904 Keywords : haspin * aurora kinase * spindle * MTOC * oocyte Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.431, year: 2016

  8. Detection of aurorae in light time of the day at rocket investigations of atmospheric radiation

    International Nuclear Information System (INIS)

    Khokhlov, V.N.

    1996-01-01

    Results of rocket observations of aurorae in light time of the day were analyzed. Characteristic features of Rayleigh scattering, day airglow, solar radiation, scattered in the device and near-rocket glow were considered. The contribution of aurorae in the light time of the day was determined on the basis of analyzing results of rocket experiments, laboratory measurements and theoretical simulation. 4 refs., 2 figs

  9. Preclinical validation of Aurora kinases-targeting drugs in osteosarcoma

    NARCIS (Netherlands)

    Tavanti, E.; Sero, V.; Vella, S.; Fanelli, M.; Michelacci, F.; Landuzzi, L.; Magagnoli, G.; Versteeg, R.; Picci, P.; Hattinger, C. M.; Serra, M.

    2013-01-01

    Aurora kinases are key regulators of cell cycle and represent new promising therapeutic targets in several human tumours. Biological relevance of Aurora kinase-A and -B was assessed on osteosarcoma clinical samples and by silencing these genes with specific siRNA in three human osteosarcoma cell

  10. AuroraMAX!

    Science.gov (United States)

    Donovan, E.; Spanswick, E. L.; Chicoine, R.; Pugsley, J.; Langlois, P.

    2011-12-01

    AuroraMAX is a public outreach and education initiative that brings auroral images to the public in real time. AuroraMAX utilizes an observing station located just outside Yellowknife, Canada. The station houses a digital All-Sky Imager (ASI) that collects full-colour images of the night sky every six seconds. These images are then transmitted via satellite internet to our web server, where they are made instantly available to the public. Over the last two years this program has rapidly become one of the most successful outreach programs in the history of Space Science in Canada, with hundreds of thousands of distinct visitors to the CSA AuroraMAX website, thousands of followers on social media, and hundreds of newspaper, magazine, radio, and television spots. Over the next few years, the project will expand to include a high-resolution SLR delivering real-time auroral images (also from Yellowknife), as well as a program where astronauts on the ISS will take pictures of the aurora with a handheld SLR. The objectives of AuroraMAX are public outreach and education. The ASI design, operation, and software were based on infrastructure that was developed for the highly successful ASI component of the NASA THEMIS mission as well as the Canadian Space Agency (CSA) Canadian GeoSpace Monitoring (CGSM) program. So from an education and public outreach perspective, AuroraMAX is a single camera operating in the Canadian north. On the other hand, AuroraMAX is one of nearly 40 All-Sky Imagers that are operating across North America. The AuroraMAX camera produces data that is seamlessly integrated with the CGSM ASI data, and made widely available to the Space Science community through open-access web and FTP sites. One of our objectives in the next few years is to incorporate some of the data from the THEMIS and CGSM imagers into the AuroraMAX system, to maximize viewing opportunities and generate more real-time data for public outreach. This is an exemplar of a program that

  11. Glow discharging device

    International Nuclear Information System (INIS)

    Maeno, Katsuki; Kawasaki, Kozo; Hiratsuka, Hajime; Kawashima, Shuichi.

    1989-01-01

    In a thermonuclear device, etc. impurities adsorbed to inner walls of a vacuum vessel by glow discharge are released to clean the vacuum vessel for preventing intrusion of the impurities into plasmas. The object of the present invention is to minimize the capacity of a power source equipment for the glow discharge device to the least extent. That is, a stabilization resistance is connected in series between each of a plurality of anodes which are inserted and arranged at the inside of a vacuum vessel as a cathode and a power source respectively. The resistance value R is selected so as to satisfy the relation: R < (Vi - Vm)/Ii, in which Vi: glow discharge starting voltage, Vm: glow discharge keeping voltage, Ii: glow discharge starting current. Accordingly, if a voltage is applied from a power source to a plurality of anodes, scattering of electric discharge between the anodes can be suppressed and the effect of voltage drop during discharge by the stabilization resistance can be eliminated. As a result, it is possible to provide an economically advantageous glow discharge device with the capacity for the power source facility being to the least extent. (K.M.)

  12. Theory of aurora formation

    International Nuclear Information System (INIS)

    Hasegawa, Akira.

    1975-04-01

    A new theory of aurora formation is presented based on Alfven wave-electron interaction. The theory explains consistently 1) the electron acceleration process, 2) the formation of auroral layers and 3) the long wave formation in the longitudinal direction. (auth.)

  13. Aurora energy resources

    Energy Technology Data Exchange (ETDEWEB)

    Falconer, D. [Aurora Energy Resources Inc., Vancouver, British Columbia (Canada)

    2009-07-01

    This paper describes the structure and activities of Aurora, a mining company which owns uranium mines, open pit mines at Michelin, Jacques Lake and Rainbow and underground mines at Michelin and Jacques Lake. The paper discusses issues such as economics, mining, processing and environmental impacts.

  14. GlowPhones

    DEFF Research Database (Denmark)

    Merritt, Timothy Robert; Nielsen, Christine Linding; Jakobsen, Frederik Lund

    2017-01-01

    Location-based mobile games often utilize built-in sensors for supporting game experiences tied to the physical world, yet the visual user interface remains constrained to the small high-resolution screen. GlowPhones is a location-based mobile social game using low-resolution displays to augment...... the physical space and move the attention away from the mobile screen. Players explore the physical world and collaborate to overcome challenges relying on the screen glow intensity emitted from the phone’s screen and light flash frequency of the camera flash for navigation. Three game stages explore proxemics...

  15. Structural Biology Insight for the Design of Sub-type Selective Aurora Kinase Inhibitors.

    Science.gov (United States)

    Sarvagalla, Sailu; Coumar, Mohane Selvaraj

    2015-01-01

    Aurora kinase A, B and C, are key regulators of mitosis and are over expressed in many of the human cancers, making them an ideal drug target for cancer chemotherapy. Currently, over a dozen of Aurora kinase inhibitors are in various phases of clinical development. The majority of the inhibitors (VX-680/MK-0457, PHA-739358, CYC116, SNS-314, AMG 900, AT-9283, SCH- 1473759, ABT-348, PF-03814735, R-763/AS-703569, KW-2449 and TAK-901) are pan-selective (isoform non-selective) and few are Aurora A (MLN8054, MLN8237, VX-689/MK5108 and ENMD 2076) and Aurora B (AZD1152 and GSK1070916) sub-type selective. Despite the intensive research efforts in the past decade, no Aurora kinase inhibitor has reached the market. Recent evidence suggests that the sub-type selective Aurora kinase A inhibitor could possess advantages over pan-selective Aurora inhibitors, by avoiding Aurora B mediated neutropenia. However, sub-type selective Aurora kinase A inhibitor design is very challenging due to the similarity in the active site among the isoforms. Structural biology and computational aspects pertaining to the design of Aurora kinase inhibitors were analyzed and found that a possible means to develop sub-type selective inhibitor is by targeting Aurora A specific residues (Leu215, Thr217 and Arg220) or Aurora B specific residues (Arg159, Glu161 and Lys164), near the solvent exposed region of the protein. Particularly, a useful strategy for the design of sub-type selective Aurora A inhibitor could be by targeting Thr217 residue as in the case of MLN8054. Further preclinical and clinical studies with the sub-type selective Aurora inhibitors could help bring them to the market for the treatment of cancer.

  16. Evolutionary relationships of Aurora kinases: Implications for model organism studies and the development of anti-cancer drugs

    Directory of Open Access Journals (Sweden)

    Patrick Denis R

    2004-10-01

    Full Text Available Abstract Background As key regulators of mitotic chromosome segregation, the Aurora family of serine/threonine kinases play an important role in cell division. Abnormalities in Aurora kinases have been strongly linked with cancer, which has lead to the recent development of new classes of anti-cancer drugs that specifically target the ATP-binding domain of these kinases. From an evolutionary perspective, the species distribution of the Aurora kinase family is complex. Mammals uniquely have three Aurora kinases, Aurora-A, Aurora-B, and Aurora-C, while for other metazoans, including the frog, fruitfly and nematode, only Aurora-A and Aurora-B kinases are known. The fungi have a single Aurora-like homolog. Based on the tacit assumption of orthology to human counterparts, model organism studies have been central to the functional characterization of Aurora kinases. However, the ortholog and paralog relationships of these kinases across various species have not been rigorously examined. Here, we present comprehensive evolutionary analyses of the Aurora kinase family. Results Phylogenetic trees suggest that all three vertebrate Auroras evolved from a single urochordate ancestor. Specifically, Aurora-A is an orthologous lineage in cold-blooded vertebrates and mammals, while structurally similar Aurora-B and Aurora-C evolved more recently in mammals from a duplication of an ancestral Aurora-B/C gene found in cold-blooded vertebrates. All so-called Aurora-A and Aurora-B kinases of non-chordates are ancestral to the clade of chordate Auroras and, therefore, are not strictly orthologous to vertebrate counterparts. Comparisons of human Aurora-B and Aurora-C sequences to the resolved 3D structure of human Aurora-A lends further support to the evolutionary scenario that vertebrate Aurora-B and Aurora-C are closely related paralogs. Of the 26 residues lining the ATP-binding active site, only three were variant and all were specific to Aurora-A. Conclusions In

  17. Drifting black aurorae?

    International Nuclear Information System (INIS)

    Schoute-Vanneck, H.; Scourfield, M.W.J.; Nielsen, E.

    1990-01-01

    Characteristics of eastward drifting forms, previously described in the literature as black aurorae, have been identified in low-light level TV camera data. The TV field of view was within the field of view of STARE and that of an all-sky camera. On the basis of these observations the authors propose that these auroral forms are a manifestation of folds or waves on the borders of auroral bands propagating along the dark regions between neighboring auroral bands. Conditions under which the folds or waves occur are compatible with their formation by the Kelvin-Helmholtz electrostatic instability

  18. IQGAP1 interacts with Aurora-A and enhances its stability and its role in cancer

    International Nuclear Information System (INIS)

    Yin, Ning; Shi, Ji; Wang, Dapeng; Tong, Tong; Wang, Mingrong; Fan, Feiyue; Zhan, Qimin

    2012-01-01

    Highlights: ► IQGAP1 interacts with Aurora-A through its RGCt domain. ► Overexpression of IQGAP1 prevents ubiquitination of Aurora-A. ► Overexpression of IQGAP1 enhances the protein stability of Aurora-A. ► Overexpression of IQGAP1 promotes the kinase activity of Aurora-A. -- Abstract: IQGAP1, a ubiquitously expressed scaffold protein, has been identified in a wide range of organisms. It participates in multiple aspects of cellular events by binding to and regulating numerous interacting proteins. In our present study, we identified a new IQGAP1 binding protein named Aurora-A which is an oncogenic protein and overexpressed in various types of human tumors. In vitro analysis with GST-Aurora-A fusion proteins showed a physical interaction between Aurora-A and IQGAP1. Moreover, the binding also occurred in HeLa cells as endogenous Aurora-A co-immunoprecipitated with IQGAP1 from the cell lysates. Overexpression of IQGAP1 resulted in an elevation of both expression and activity of Aurora-A kinase. Endogenous IQGAP1 knockdown by siRNA promoted Aurora-A degradation whereas IQGAP1 overexpression enhanced the stability of Aurora-A. Additionally, we documented that the IQGAP1-induced cell proliferation was suppressed by knocking down Aurora-A expression. Taken together, our results showed an unidentified relationship between Aurora-A and IQGAP1, and provided a new insight into the molecular mechanism by which IQGAP1 played a regulatory role in cancer.

  19. Aurora laser optical system

    International Nuclear Information System (INIS)

    Hanlon, J.A.; McLeod, J.

    1987-01-01

    Aurora is the Los Alamos short-pulse high-power krypton fluoride laser system. It is primarily an end-to-end technology demonstration prototype for large-scale UV laser systems of interest for short-wavelength inertial confinement fusion (ICF) investigations. The system is designed to employ optical angular multiplexing and aerial amplification by electron-beam-driven KrF laser amplifiers to deliver to ICF targets a stack of pulses with a duration of 5 ns containing several kilojoules at a wavelength of 248 nm. A program of high-energy density plasma physics investigations is now planned, and a sophisticated target chamber was constructed. The authors describe the design of the optical system for Aurora and report its status. This optical system was designed and is being constructed in two phases. The first phase carries only through the amplifier train and does not include a target chamber or any demultiplexing. Installation should be complete, and some performance results should be available. The second phase provides demultiplexing and carries the laser light to target. The complete design is reported

  20. Aurora B kinase inhibition in mitosis: strategies for optimising the use of aurora kinase inhibitors such as AT9283.

    Science.gov (United States)

    Curry, Jayne; Angove, Hayley; Fazal, Lynsey; Lyons, John; Reule, Matthias; Thompson, Neil; Wallis, Nicola

    2009-06-15

    Aurora kinases play a key role in regulating mitotic division and are attractive oncology targets. AT9283, a multi-targeted kinase inhibitor with potent activity against Aurora A and B kinases, inhibited growth and survival of multiple solid tumor cell lines and was efficacious in mouse xenograft models. AT9283-treatment resulted in endoreduplication and ablation of serine-10 histone H3 phosphorylation in both cells and tumor samples, confirming that in these models it acts as an Aurora B kinase inhibitor. In vitro studies demonstrated that exposure to AT9283 for one complete cell cycle committed an entire population of p53 checkpoint-compromised cells (HCT116) to multinucleation and death whereas treatment of p53 checkpoint-competent cells (HMEC, A549) for a similar length of time led to a reversible arrest of cells with 4N DNA. Further studies in synchronized cell populations suggested that exposure to AT9283 during mitosis was critical for optimal cytotoxicity. We therefore investigated ways in which these properties might be exploited to optimize the efficacy and therapeutic index of Aurora kinase inhibitors for p53 checkpoint compromised tumors in vivo. Combining Aurora B kinase inhibition with paclitaxel, which arrests cells in mitosis, in a xenograft model resulted in promising efficacy without additional toxicity. These findings have implications for optimizing the efficacy of Aurora kinase inhibitors in clinical practice.

  1. Aurorae in Australian Aboriginal Traditions

    Science.gov (United States)

    Hamacher, Duane W.

    2013-07-01

    Transient celestial phenomena feature prominently in the astronomical knowledge and traditions of Aboriginal Australians. In this paper, I collect accounts of the Aurora Australis from the literature regarding Aboriginal culture. Using previous studies of meteors, eclipses, and comets in Aboriginal traditions, I anticipate that the physical properties of aurora, such as their generally red colour as seen from southern Australia, will be associated with fire, death, blood, and evil spirits. The survey reveals this to be the case and also explores historical auroral events in Aboriginal cultures, aurorae in rock art, and briefly compares Aboriginal auroral traditions with other global indigenous groups, including the Maori of New Zealand.

  2. Adventures in search of auroras

    Science.gov (United States)

    Forsyth, Colin

    2016-09-01

    In her book Aurora: In Search of the Northern Lights, Melanie Windridge describes travelling around the Arctic Circle on a quest to see the biggest and best auroral displays and to understand the physics that drives them.

  3. The Aurora B kinase in chromosome biorientation and spindle checkpoint signalling

    Directory of Open Access Journals (Sweden)

    Veronica eKrenn

    2015-10-01

    Full Text Available Aurora B, a member of the Aurora family of serine/threonine protein kinases, is a key player in chromosome segregation. As part of a macromolecular complex known as the chromosome passenger complex, Aurora B concentrates early during mitosis in the proximity of centromeres and kinetochores, the sites of attachment of chromosomes to spindle microtubules. There, it contributes to a number of processes that impart fidelity to cell division, including kinetochore stabilization, kinetochore-microtubule attachment, and the regulation of a surveillance mechanism named the spindle assembly checkpoint. In the regulation of these processes, Aurora B is the fulcrum of a remarkably complex network of interactions that feed back on its localization and activation state. In this review we discuss the multiple roles of Aurora B during mitosis, focusing in particular on its role at centromeres and kinetochores. Many details of the network of interactions at these locations remain poorly understood, and we focus here on several crucial outstanding questions.

  4. The Aurora space launcher concept

    Science.gov (United States)

    Kopp, Alexander; Stappert, Sven; Mattsson, David; Olofsson, Kurt; Marklund, Erik; Kurth, Guido; Mooij, Erwin; Roorda, Evelyne

    2017-11-01

    This paper gives an overview about the Aurora reusable space launcher concept study that was initiated in late-2015/early-2016. Within the Aurora study, several spaceplane-like vehicle configurations with different geometries, propulsion systems and mission profiles will be designed, investigated and evaluated with respect to their technical and economic feasibility. The first part of this paper will discuss the study logic and the current status of the Aurora studies and introduces the first vehicle configurations and their system design status. As the identification of highly efficient structural designs is of particular interest for Aurora, the structural design and analysis approach will be discussed in higher level of detail. A special design feature of the Aurora vehicle configurations is the utilization of the novel thin-ply composite material technology for structural mass reductions. Therefore, the second part of this paper will briefly discuss this technology and investigate the application and potential mass savings on vehicle level within simplified structural analysis studies. The results indicate that significant mass savings could be possible. Finally, an outlook on the next steps is provided.

  5. The Aurora space launcher concept

    Science.gov (United States)

    Kopp, Alexander; Stappert, Sven; Mattsson, David; Olofsson, Kurt; Marklund, Erik; Kurth, Guido; Mooij, Erwin; Roorda, Evelyne

    2018-06-01

    This paper gives an overview about the Aurora reusable space launcher concept study that was initiated in late-2015/early-2016. Within the Aurora study, several spaceplane-like vehicle configurations with different geometries, propulsion systems and mission profiles will be designed, investigated and evaluated with respect to their technical and economic feasibility. The first part of this paper will discuss the study logic and the current status of the Aurora studies and introduces the first vehicle configurations and their system design status. As the identification of highly efficient structural designs is of particular interest for Aurora, the structural design and analysis approach will be discussed in higher level of detail. A special design feature of the Aurora vehicle configurations is the utilization of the novel thin-ply composite material technology for structural mass reductions. Therefore, the second part of this paper will briefly discuss this technology and investigate the application and potential mass savings on vehicle level within simplified structural analysis studies. The results indicate that significant mass savings could be possible. Finally, an outlook on the next steps is provided.

  6. Aurora status and plans

    International Nuclear Information System (INIS)

    Kristal, R.; Blair, L.S.; Burrows, M.D.

    1987-10-01

    Aurora is a short wavelength (248 nm) 10 to kJ KrF laser systems in the ICF program at Los Alamos National Laboratory. It is both an experiment in driver technology and a means for studying target performance using KrF laser light. Both features will be used to help evaluate the uv excimer laser as a viable fusion driver. The system has been designed to employ several electron-beam pumped amplifiers in series, with a final aperture of one meter square, to amplify 96 angularly mulitplexed 5 ns beamlets to the 10 kJ level. In Phase I, 48 of these beamlets are brought to target by demultiplexing and focusing with f26 optics. The beamlet ensemble, contained within an f1.9 bundle, is focused as a single beam;however, pointing is done individually. Spot size in the target plane is variable from 0.1-4 mm, with maximum averaged intensity of /similar to/ 4 x 10 15 Wcm 2 . The illumination geometry is designed specifically for several classes of important target physics experiments. These include: energy flow, symmetry and preheat studies related to indirectly driven targets;x-ray conversion and plasma coupling characterization on disc targets, and hydrodynamic instability studies in planar geometry. System integration is proceeding toward initial target experiments in /similar to/ late 1988. Ninety-six beam amplification through the penultimate amplifier has been obtained at the sub-kJ level. Installation of beam train optics is proceeding, and the target system vacuum envelope is in place. 18 refs., 12 figs., 2 tabs

  7. Image analysis of dayside aurora

    International Nuclear Information System (INIS)

    Lybekk, B.

    1989-12-01

    Ground based observations from Svalbard of the midday aurora by all sky cameras and meridian scanning photometers showed the sporadic occurrence of discrete auroral forms within or near the stable cusp or cleft aurora. Some of these forms appeared near the equatorward boundary of the stable cusp/cleft aurora and moved westward and northward. The duration of the whole event was typically less than 10 minutes. Series of such events were observed when the cusp/cleft was located at low latitudes. Satellite measurements of magnetic field and ion drift components above auroral strucures gave detailed information of auroral electrodynamics in the cusp/cleft ionosphere. Satellite observations of the dayside oval at ∼ 09 MLT showed that auroral emissions can be separated in different latitudinal zones with corresponding structures in the particle precipitation. The ground based optical instruments at Svalbard measured the stationary cleft aurora produced by soft electrons and transient discrete arcs produced by precipitating keV electrons. 89 refs

  8. Indomethacin promotes apoptosis in gastric cancer cells through concomitant degradation of Survivin and Aurora B kinase proteins.

    Science.gov (United States)

    Chiou, Shiun-Kwei; Hoa, Neil; Hodges, Amy; Ge, Lishen; Jadus, Martin R

    2014-09-01

    Regular usage of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with reduced incidence of a variety of cancers. The molecular mechanisms underlying these chemopreventive effects remain poorly understood. This current investigation showed that in gastric cancer cells: (1) Indomethacin treatment enhanced the degradation of chromosomal passenger proteins, Survivin and Aurora B kinase; (2) Indomethacin treatment down-regulated Aurora B kinase activity in a cell cycle-independent fashion; (3) siRNA knockdown of Survivin level promoted Aurora B kinase protein degradation, and vice versa; (4) ectopic overexpression of Survivin blocked reduction of Aurora B kinase level and activity by indomethacin treatment, and vice versa; (5) siRNA knockdown of Aurora B kinase level and AZD1152 inhibition of its activity induced apoptosis, and overexpression of Aurora B kinase inhibited indomethacin-induced apoptosis; (6) indomethacin treatment reduced Aurora B kinase level, coinciding with reduction of Survivin level and induction of apoptosis, in KATO III and HT-29 cells, and in mouse gastric mucosa. A role for Aurora B kinase function in NSAID-induced apoptosis was not previously explored. Thus this report provides better understanding of the molecular mechanisms underlying the anti-cancer effect of NSAIDs by elucidating a significant role for Aurora B kinase in indomethacin-induced apoptosis.

  9. Arsenic-induced Aurora-A activation contributes to chromosome instability and tumorigenesis

    Science.gov (United States)

    Wu, Chin-Han; Tseng, Ya-Shih; Yang, Chao-Chun; Kao, Yu-Ting; Sheu, Hamm-Ming; Liu, Hsiao-Sheng

    2013-11-01

    Arsenic may cause serious environmental pollution and is a serious industrial problem. Depending on the dosage, arsenic may trigger the cells undergoing either proliferation or apoptosis-related cell death. Because of lack of the proper animal model to study arsenic induced tumorigenesis, the accurate risk level of arsenic exposure has not been determined. Arsenic shows genotoxic effect on human beings who uptake water contaminated by arsenic. Chromosome aberration is frequently detected in arsenic exposure-related diseases and is associated with increased oxidative stress and decreased DNA repairing activity, but the underlying mechanism remains elusive. Aurora-A is a mitotic kinase, over-expression of Aurora-A leads to centrosome amplification, chromosomal instability and cell transformation. We revealed that Aurora-A is over-expressed in the skin and bladder cancer patients from blackfoot-disease endemic areas. Our cell line studies reveal that arsenic exposure between 0.5 μM and 1 μM for 2-7 days are able to induce Aurora-A expression and activation based on promoter activity, RNA and protein analysis. Aurora-A overexpression further increases the frequency of unsymmetrical chromosome segregation through centrosome amplification followed by cell population accumulated at S phase in immortalized keratinocyte (HaCaT) and uroepithelial cells (E7). Furthermore, Aurora-A over-expression was sustained for 1-4 weeks by chronic treatment of immortalized bladder and skin cells with NaAsO2. Aurora-A promoter methylation and gene amplification was not detected in the long-term arsenic treated E7 cells. Furthermore, the expression level of E2F1 transcription factor (E2F1) is increased in the presence of arsenic, and arsenic-related Aurora-A over-expression is transcriptionally regulated by E2F1. We further demonstrated that overexpression of Aurora-A and mutant Ha-ras or Aurora-A and mutant p53 may act additively to trigger arsenic-related bladder and skin cancer

  10. Aurora oil switch upgrade program

    International Nuclear Information System (INIS)

    Warren, T.

    1989-03-01

    This report describes the short pulse synchronization requirements, the original Aurora trigger scheme, and the PI/SNLA approach to improving the synchronization. It also describes the oil switching design study undertaken as the first phase of the program. A discussion of oil-switch closure analysis and the conceptual design motivated by this analysis are presented. This paper also describes the oil-switch trigger pulser tests required to validate the concept. This includes the design of the testing facility, a description of the test goals, and a discussion of the results. This paper finally describes oil-switch trigger pulser testing on one of the four Aurora Blumlein modules, which includes the hardware design and operation, the testing goals, hardware installation, and test results. 9 refs., 26 figs

  11. Hydrogeology baseline study Aurora Mine

    International Nuclear Information System (INIS)

    1996-01-01

    A baseline hydrogeologic study was conducted in the area of Syncrude's proposed Aurora Mine in order to develop a conceptual regional hydrogeologic model for the area that could be used to understand groundwater flow conditions. Geologic information was obtained from over 2,000 coreholes and from data obtained between 1980 and 1996 regarding water level for the basal aquifer. A 3-D numerical groundwater flow model was developed to provide quantitative estimates of the potential environmental impacts of the proposed mining operations on the groundwater flow system. The information was presented in the context of a regional study area which encompassed much of the Athabasca Oil Sands Region, and a local study area which was defined by the lowlands of the Muskeg River Basin. Characteristics of the topography, hydrology, climate, geology, and hydrogeology of the region are described. The conclusion is that groundwater flow in the aquifer occurs mostly in a westerly direction beneath the Aurora Mine towards its inferred discharge location along the Athabasca River. Baseflow in the Muskeg River is mostly related to discharge from shallow surficial aquifers. Water in the river under baseflow conditions was fresh, of calcium-carbonate type, with very little indication of mineralization associated with deeper groundwater in the Aurora Mine area. 44 refs., 5 tabs., 31 figs

  12. Significance of Aurora B overexpression in hepatocellular carcinoma. Aurora B Overexpression in HCC

    International Nuclear Information System (INIS)

    Lin, Zhong-Zhe; Jeng, Yung-Ming; Hu, Fu-Chang; Pan, Hung-Wei; Tsao, Hsin-Wei; Lai, Po-Lin; Lee, Po-Huang; Cheng, Ann-Lii; Hsu, Hey-Chi

    2010-01-01

    To investigate the significance of Aurora B expression in hepatocellular carcinoma (HCC). The Aurora B and Aurora A mRNA level was measured in 160 HCCs and the paired nontumorous liver tissues by reverse transcription-polymerase chain reaction. Mutations of the p53 and β-catenin genes were analyzed in 134 and 150 tumors, respectively, by direct sequencing of exon 2 to exon 11 of p53 and exon 3 of β-catenin. Anticancer effects of AZD1152-HQPA, an Aurora B kinase selective inhibitor, were examined in Huh-7 and Hep3B cell lines. Aurora B was overexpressed in 98 (61%) of 160 HCCs and in all 7 HCC cell lines examined. The overexpression of Aurora B was associated with Aurora A overexpression (P = 0.0003) and p53 mutation (P = 0.002) and was inversely associated with β-catenin mutation (P = 0.002). Aurora B overexpression correlated with worse clinicopathologic characteristics. Multivariate analysis confirmed that Aurora B overexpression was an independent poor prognostic factor, despite its interaction with Aurora A overexpression and mutations of p53 and β-catenin. In Huh-7 and Hep3B cells, AZD1152-HQPA induced proliferation blockade, histone H3 (Ser10) dephosphorylation, cell cycle disturbance, and apoptosis. Aurora B overexpression is an independent molecular marker predicting tumor invasiveness and poor prognosis of HCC. Aurora B kinase selective inhibitors are potential therapeutic agents for HCC treatment

  13. Dissolution glow curve in LLD

    International Nuclear Information System (INIS)

    Haverkamp, U.; Wiezorek, C.; Poetter, R.

    1990-01-01

    Lyoluminescence dosimetry is based upon light emission during dissolution of previously irradiated dosimetric materials. The lyoluminescence signal is expressed in the dissolution glow curve. These curves begin, depending on the dissolution system, with a high peak followed by an exponentially decreasing intensity. System parameters that influence the graph of the dissolution glow curve, are, for example, injection speed, temperature and pH value of the solution and the design of the dissolution cell. The initial peak does not significantly correlate with the absorbed dose, it is mainly an effect of the injection. The decay of the curve consists of two exponential components: one fast and one slow. The components depend on the absorbed dose and the dosimetric materials used. In particular, the slow component correlates with the absorbed dose. In contrast to the fast component the argument of the exponential function of the slow component is independent of the dosimetric materials investigated: trehalose, glucose and mannitol. The maximum value, following the peak of the curve, and the integral light output are a measure of the absorbed dose. The reason for the different light outputs of various dosimetric materials after irradiation with the same dose is the differing solubility. The character of the dissolution glow curves is the same following irradiation with photons, electrons or neutrons. (author)

  14. Double layers above the aurora

    International Nuclear Information System (INIS)

    Temerin, M.; Mozer, F.S.

    1987-01-01

    Two different kinds of double layers were found in association with auroral precipitation. One of these is the so-called electrostatic shock, which is oriented at an oblique angle to the magnetic field in such a way that the perpendicular electric field is much larger than the parallel electric field. This type of double layer is often found at the edges of regions of upflowing ion beams and the direction of the electric fields in the shock points toward the ion beam. The potential drop through the shock can be several kV and is comparable to the total potential needed to produce auroral acceleration. Instabilities associated with the shock may generate obliquely propagating Alfven waves, which may accelerate electrons to produce flickering auroras. The flickering aurora provides evidence that the electrostatic shock may have large temporal fluctuations. The other kind of double layer is the small-amplitude double layer found in regions of upward flowing in beams, often in association with electrostatic ion cyclotron waves. The parallel and perpendicular electric fields in these structures are comparable in magnitude. The associated potentials are a few eV. Since many such double layers are found in regions of upward flowing ion beams, the combined potential drop through a set of these double layers can be substantial

  15. Common Gamma-ray Glows above Thunderclouds

    Science.gov (United States)

    Kelley, Nicole; Smith, David; Dwyer, Joseph; Hazelton, Bryna; Grefenstette, Brian; Lowell, Alex; Splitt, Michael; Lazarus, Steven; Rassoul, Hamid

    2013-04-01

    Gamma-ray glows are continuous, long duration gamma- and x-ray emission seen coming from thunderclouds. The Airborne for Energetic Lightning Emissions (ADELE) observed 12 gamma-ray glows during its summer 2009 flight campaign over the areas of Colorado and Florida in the United States. For these glows we shall present their spectra, relationship to lightning activity and how their duration and size changes as a function of distance. Gamma-ray glows follow the relativistic runaway electron avalanche (RREA) spectrum and have been previously measured from the ground and inside the cloud. ADELE measured most glows as it flew above the screening layer of the cloud. During the brightest glow on August 21, 2009, we can show that we are flying directly into a downward facing relativistic runaway avalanche, indicative of flying between the upper positive and negative screening layer of the cloud. In order to explain the brightness of this glow, RREA with an electric field approaching the limit for relativistic feedback must be occurring. Using all 12 glows, we show that lightning activity diminishes during the onset of the glow. Using this along with the fact that glows occur as the field approaches the level necessary for feedback, we attempt to distinguish between two possibilities: that glows are evidence that RREA with feedback, rather than lightning, is sometimes the primary channel for discharging the cloud, or else that the overall discharging is still controlled by lightning, with glows simply appearing during times when a subsidence of lightning allows the field to rise above the threshold for RREA.

  16. Occurrence and average behavior of pulsating aurora

    Science.gov (United States)

    Partamies, N.; Whiter, D.; Kadokura, A.; Kauristie, K.; Nesse Tyssøy, H.; Massetti, S.; Stauning, P.; Raita, T.

    2017-05-01

    Motivated by recent event studies and modeling efforts on pulsating aurora, which conclude that the precipitation energy during these events is high enough to cause significant chemical changes in the mesosphere, this study looks for the bulk behavior of auroral pulsations. Based on about 400 pulsating aurora events, we outline the typical duration, geomagnetic conditions, and change in the peak emission height for the events. We show that the auroral peak emission height for both green and blue emission decreases by about 8 km at the start of the pulsating aurora interval. This brings the hardest 10% of the electrons down to about 90 km altitude. The median duration of pulsating aurora is about 1.4 h. This value is a conservative estimate since in many cases the end of event is limited by the end of auroral imaging for the night or the aurora drifting out of the camera field of view. The longest durations of auroral pulsations are observed during events which start within the substorm recovery phases. As a result, the geomagnetic indices are not able to describe pulsating aurora. Simultaneous Antarctic auroral images were found for 10 pulsating aurora events. In eight cases auroral pulsations were seen in the southern hemispheric data as well, suggesting an equatorial precipitation source and a frequent interhemispheric occurrence. The long lifetimes of pulsating aurora, their interhemispheric occurrence, and the relatively high-precipitation energies make this type of aurora an effective energy deposition process which is easy to identify from the ground-based image data.

  17. Aurora A kinase RNAi and small molecule inhibition of Aurora kinases with VE-465 induce apoptotic death in multiple myeloma cells.

    Science.gov (United States)

    Evans, Robert; Naber, Claudia; Steffler, Tara; Checkland, Tamara; Keats, Jonathan; Maxwell, Christopher; Perry, Troy; Chau, Heidi; Belch, Andrew; Pilarski, Linda; Reiman, Tony

    2008-03-01

    The expression of RHAMM and other centrosome-associated genes are known to correlate with the extent of centrosome amplification in multiple myeloma, and with poor prognosis. RHAMM has a significant interaction with TPX2, a protein which regulates the localization and action of Aurora A kinase (AURKA) at the spindle poles. AURKA is known to be a central determinant of centrosome and spindle function and is a target for cancer therapy. Given these observations, we investigated the role of Aurora kinases as therapeutic targets in myeloma. Here we report that AURKA is expressed ubiquitously in myeloma, to varying degrees, in both cell lines and patients' bone marrow plasma cells. siRNA targeting AURKA induces apoptotic cell death in myeloma cell lines. The Aurora kinase inhibitor VE-465 also induces apoptosis and death in myeloma cell lines and primary myeloma plasma cells. The combination of VE-465 and dexamethasone improves cell killing compared with the use of either agent alone, even in cells resistant to the single agents. The phenotype of myeloma cells treated with VE-465 is consistent with published reports on the effects of Aurora kinase inhibition. Aurora kinase inhibitors should be pursued as potential treatments for myeloma.

  18. Dynamics of the dayside aurora

    International Nuclear Information System (INIS)

    Creutzberg, F.; Mcewen, D.J.

    1982-01-01

    A clearer picture of the dynamical nature of the post-noon aurora has been obtained with instrumental studies during rocket flights over the Northwest Territories of Canada. A sequence of meridian scans showing the measured intensities of the emissions along the meridian from south to north is presented. An all-sky picture of an auroral event is presented which shows a very narrow arc running through the zenith in an east-west direction, typical of many occurring during the period 1-3 hrs after local magnetic noon. A contemporaneous meridian scan taken over the same location shows a narrow spike in the zenith. The frequent occurrence of these narrow, transient auroral arcs with lifetimes of 1-2 minutes, resulting from inverted V events, is discussed

  19. The mechanism of pulsating aurora

    International Nuclear Information System (INIS)

    Johnstone, A.D.

    1983-01-01

    New measurement using ground-based techniques, sounding-rockets and geostationary satellites show that pulsating aurora is almost certainly caused by a modulation of the precipitating electron beam. The modulation is probably imposed near the magnetic equator by an interaction with ELF waves which are observed to be modulated at the same frequency. The measured wave intensity is not strong enough to cause pulsations by variation of the rate of pitch angle diffusion so it is suggested that the pulsation is caused by a coherent interaction involving the generation of ELF chorus. The periodicity arises because the chorus is shut-off after approximately half a bounce period when the increased rate of precipitation removes most of the resonant electrons. The supply is then replenished by pitch angle diffusion

  20. Aurora Bertrana: bringing "otherness" home

    Directory of Open Access Journals (Sweden)

    M. Pilar Godayol i Nogué

    2008-01-01

    Full Text Available “Decidida a viure al preu que sigui” underscores contemporary writer Maria-Antònia Oliver in her prologue to Aurora Bertrana’s fourth book, El Marroc sensual i fanàtic (1936. The urge to travel, to explore the world and to slake her thirst for new experiences shaped much of the personality and the work of this Girona-born writer. Taking her own travels as a starting point, Bertrana distinguished herself in the genre of travel writing on exotic countries, which at that time underwent a significant revival in Catalonia. Bertrana’s originality lies partly in the image of the woman traveller that she consciously cultivated for herself, and partly in the way she narrates her travels. This article seeks to recover this author and make visible her singular way of presenting otherness.

  1. Aurora Police Lieutenant Gains Intelligence Insight

    OpenAIRE

    Center for Homeland Defense and Security

    2012-01-01

    Center for Homeland Defense and Security, PRESS RELEASES Aurora (Colo.) Police Lt. Sam McGhee has served numerous traditional roles in law enforcement such as emergency services coordinator, media relations manager, narcotics and intelligence commander and sector commander. Currently,...

  2. Spitzbergen - a unique site for observing aurorae

    International Nuclear Information System (INIS)

    Egeland, A.; Sandholt, P.E.

    1981-01-01

    An international research project situated on Spitzbergen was begun in 1978-79 by Norwegian, British, and American scientists. The main purpose of the project is systematic studies of midday aurorae. Midday aurorae are a new and interesting research theme for which Norway has special qualifications. Through international cooperation a comprehensive instrument park and a practical and economic distribution of tasks have been attained. (Auth./JIW)

  3. Numerical analysis of thermoluminescence glow curves

    International Nuclear Information System (INIS)

    Gomez Ros, J. M.; Delgado, A.

    1989-01-01

    This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs

  4. Glow discharge in singlet oxygen

    International Nuclear Information System (INIS)

    Vagin, N.P.; Ionin, A.A.; Klimachev, Yu.M.; Sinitsyn, D.V.; Yuryshev, N.N.; Kochetov, I.V.; Napartovich, A.P.

    2003-01-01

    Currently, there is no experimental data on the plasma balance in gas mixtures with a high content of singlet delta oxygen O 2 ( 1 Δ g ). These data can be obtained by studying the parameters of an electric discharge in singlet oxygen produced by a chemical generator. The O 2 ( 1 Δ g ) molecules significantly change the kinetics of electrons and negative ions in plasma. Hence, the discharge conditions at low and high O 2 ( 1 Δ g ) concentrations are very different. Here, the parameters of the positive column of a glow discharge in a gas flow from a chemical singlet-oxygen generator are studied. It is experimentally shown that, at an O 2 ( 1 Δ g ) concentration of 50% and at pressures of 1.5 and 2 torr, the electric field required to sustain the discharge is considerably lower than in the case when all of the oxygen molecules are in the ground state. A theoretical model of the glow discharge is proposed whose predictions are in good agreement with the experimental data

  5. dc glow-discharge cleaning for accelerator

    International Nuclear Information System (INIS)

    Chou, T.S.; Hseuh, H.C.

    1982-01-01

    Average pressure of 1 x 10 -11 torr and vacuum stability are necessary for the successful operation of the proton storage rings such as ISABELLE. Vacuum degassing at high temperature and in situ bake-out will reduce the thermoout-gassing rate of the beam tubes to approx. 10 -13 Tl/cm 2 sec, therefore achieving the required static pressure. The vacuum instability caused by beam-induced ion desorption can be solved by dc glow discharge cleaning. With evidence from this study, the present understanding of glow discharge in a cylindrically symmetric geometry is reviewed. Argon and argon/oxygen mixture serve as plasmas in the glow. The role of oxygen in cleaning the beam tubes during the glow discharge is demonstrated experimentally. Glow discharge cleaning with and without bake-out is also studied

  6. Hubble Images Reveal Jupiter's Auroras

    Science.gov (United States)

    1996-01-01

    These images, taken by the Hubble Space Telescope, reveal changes in Jupiter's auroral emissions and how small auroral spots just outside the emission rings are linked to the planet's volcanic moon, Io. The images represent the most sensitive and sharply-detailed views ever taken of Jovian auroras.The top panel pinpoints the effects of emissions from Io, which is about the size of Earth's moon. The black-and-white image on the left, taken in visible light, shows how Io and Jupiter are linked by an invisible electrical current of charged particles called a 'flux tube.' The particles - ejected from Io (the bright spot on Jupiter's right) by volcanic eruptions - flow along Jupiter's magnetic field lines, which thread through Io, to the planet's north and south magnetic poles. This image also shows the belts of clouds surrounding Jupiter as well as the Great Red Spot.The black-and-white image on the right, taken in ultraviolet light about 15 minutes later, shows Jupiter's auroral emissions at the north and south poles. Just outside these emissions are the auroral spots. Called 'footprints,' the spots are created when the particles in Io's 'flux tube' reach Jupiter's upper atmosphere and interact with hydrogen gas, making it fluoresce. In this image, Io is not observable because it is faint in the ultraviolet.The two ultraviolet images at the bottom of the picture show how the auroral emissions change in brightness and structure as Jupiter rotates. These false-color images also reveal how the magnetic field is offset from Jupiter's spin axis by 10 to 15 degrees. In the right image, the north auroral emission is rising over the left limb; the south auroral oval is beginning to set. The image on the left, obtained on a different date, shows a full view of the north aurora, with a strong emission inside the main auroral oval.The images were taken by the telescope's Wide Field and Planetary Camera 2 between May 1994 and September 1995.This image and other images and data

  7. Is the negative glow plasma of a direct current glow discharge negatively charged?

    International Nuclear Information System (INIS)

    Bogdanov, E. A.; Saifutdinov, A. I.; Demidov, V. I.; Kudryavtsev, A. A.

    2015-01-01

    A classic problem in gas discharge physics is discussed: what is the sign of charge density in the negative glow region of a glow discharge? It is shown that traditional interpretations in text-books on gas discharge physics that states a negative charge of the negative glow plasma are based on analogies with a simple one-dimensional model of discharge. Because the real glow discharges with a positive column are always two-dimensional, the transversal (radial) term in divergence with the electric field can provide a non-monotonic axial profile of charge density in the plasma, while maintaining a positive sign. The numerical calculation of glow discharge is presented, showing a positive space charge in the negative glow under conditions, where a one-dimensional model of the discharge would predict a negative space charge

  8. Recent developments in pulsating aurora studies

    International Nuclear Information System (INIS)

    Sandahl, I.

    1985-11-01

    The field of pulsating aurora studies is reviewed. The paper begins with a short description of the characteristics of pulsating auroras and the theoretical ideas which, in view of existing experimental results, seem most important. A selection of new theoretical results and experimental results from both ground based instruments and instruments on rockets and satellites is then presented. There is now convincing evidence that the luminosity modulation is caused by a modulated flux of electron. The electron flux modulation seems to arise from a modulated resonant interaction between electrons and whistler mode waves in the equatorial plane, but the reason for the modulation is not known. Measurements concerning the drift and location of patches and the creation of Pi1 micropulsations are also deiscussed. Finally some suggestions for future research work are outlined. Optical measurements, especially with low light level TV, have proven to be of great importance in experimental studies of pulsating auroras. (author)

  9. The first accurate description of an aurora

    Science.gov (United States)

    Schröder, Wilfried

    2006-12-01

    As technology has advanced, the scientific study of auroral phenomena has increased by leaps and bounds. A look back at the earliest descriptions of aurorae offers an interesting look into how medieval scholars viewed the subjects that we study.Although there are earlier fragmentary references in the literature, the first accurate description of the aurora borealis appears to be that published by the German Catholic scholar Konrad von Megenberg (1309-1374) in his book Das Buch der Natur (The Book of Nature). The book was written between 1349 and 1350.

  10. 2-Aminobenzimidazoles as potent Aurora kinase inhibitors.

    Science.gov (United States)

    Zhong, Min; Bui, Minna; Shen, Wang; Baskaran, Subramanian; Allen, Darin A; Elling, Robert A; Flanagan, W Michael; Fung, Amy D; Hanan, Emily J; Harris, Shannon O; Heumann, Stacey A; Hoch, Ute; Ivy, Sheryl N; Jacobs, Jeffrey W; Lam, Stuart; Lee, Heman; McDowell, Robert S; Oslob, Johan D; Purkey, Hans E; Romanowski, Michael J; Silverman, Jeffrey A; Tangonan, Bradley T; Taverna, Pietro; Yang, Wenjin; Yoburn, Josh C; Yu, Chul H; Zimmerman, Kristin M; O'Brien, Tom; Lew, Willard

    2009-09-01

    This Letter describes the discovery and key structure-activity relationship (SAR) of a series of 2-aminobenzimidazoles as potent Aurora kinase inhibitors. 2-Aminobenzimidazole serves as a bioisostere of the biaryl urea residue of SNS-314 (1c), which is a potent Aurora kinase inhibitor and entered clinical testing in patients with solid tumors. Compared to SNS-314, this series of compounds offers better aqueous solubility while retaining comparable in vitro potency in biochemical and cell-based assays; in particular, 6m has also demonstrated a comparable mouse iv PK profile to SNS-314.

  11. Simultaneous Aurora-A/STK15 overexpression and centrosome amplification induce chromosomal instability in tumour cells with a MIN phenotype

    International Nuclear Information System (INIS)

    Lentini, Laura; Amato, Angela; Schillaci, Tiziana; Di Leonardo, Aldo

    2007-01-01

    to induce chromosomal instability in colon cancer cells with a MIN phenotype. Alternatively, centrosome amplification has to be associated with alterations in genes regulating mitosis progression such as Aurora-A/STK15 to trigger CIN

  12. The thermoluminescence glow-curve analysis using GlowFit - the new powerful tool for deconvolution

    International Nuclear Information System (INIS)

    Puchalska, M.; Bilski, P.

    2005-10-01

    A new computer program, GlowFit, for deconvoluting first-order kinetics thermoluminescence (TL) glow-curves has been developed. A non-linear function describing a single glow-peak is fitted to experimental points using the least squares Levenberg-Marquardt method. The main advantage of GlowFit is in its ability to resolve complex TL glow-curves consisting of strongly overlapping peaks, such as those observed in heavily doped LiF:Mg,Ti (MTT) detectors. This resolution is achieved mainly by setting constraints or by fixing selected parameters. The initial values of the fitted parameters are placed in the so-called pattern files. GlowFit is a Microsoft Windows-operated user-friendly program. Its graphic interface enables easy intuitive manipulation of glow-peaks, at the initial stage (parameter initialization) and at the final stage (manual adjustment) of fitting peak parameters to the glow-curves. The program is freely downloadable from the web site www.ifj.edu.pl/NPP/deconvolution.htm (author)

  13. Proyecto Aurora: Building a Community of Women.

    Science.gov (United States)

    Noya, Gladys R. Capella

    1997-01-01

    Describes the development of Proyecto Aurora, a program to develop and implement educational, support, and research programs to benefit low-income women in Puerto Rico. Portraits of some clients illustrate the rewards and challenges of working with this community and furthering their educational experiences and opportunities. (SLD)

  14. Source of high-voltage power supply for ozone generators at glow discharge

    International Nuclear Information System (INIS)

    Bruev, A.A.; Golota, V.I.; Zavada, L.M.; Taran, G.V.

    2000-01-01

    High-voltage power supply source on quasi-resonance inverter base which works at direct current regime is described. This source forms 20 kV voltage with 0 - 10 mA current regulation. It protects the source from current break-downs and feeds ozone generators at glow discharge

  15. High expression of nuclear survivin and Aurora B predicts poor overall survival in patients with head and neck squamous cell cancer

    Energy Technology Data Exchange (ETDEWEB)

    Erpolat, O.P.; Akmansu, M. [Medical School of Gazi Univ., Besevler-Ankara (Turkey). Dept. of Radiation Oncology; Gocun, P.U.; Karakus, E.; Akyol, G. [Medical School of Gazi Univ., Besevler-Ankara (Turkey). Dept. of Pathology

    2012-03-15

    Survivin is one of the apoptosis inhibitor proteins. Together with Aurora B, it also plays a role in regulating several aspects of mitosis. High expression of these markers is correlated with malignant behavior of various cancers and resistance to therapy. Our aim was to evaluate the prognostic role of these markers in head and neck cancers. We evaluated the expression of Aurora B and survivin in tissue specimens of 58 patients with head and neck squamous cell carcinoma using immunohistochemistry. Patients who showed high expression of cytoplasmic and nuclear survivin and Aurora B had significantly shorter overall survival (p = 0.036, p < 0.000, p = 0.032, respectively). In multivariate analysis, high expression of nuclear survivin was the only independent negative prognostic factor (p = 0.024). Moreover, it was found that high co-expression of nuclear survivin and Aurora B had a negative effect on survival in univariate (p < 0.000) and multivariate (p < 0.000) analyses. The negative prognostic values of high expression of Aurora B and high co-expression of nuclear survivin and Aurora B on survival were shown. These findings suggest that co-expression of nuclear survivin and Aurora B can be useful diagnostic markers and therapeutic targets for head and neck squamous cell carcinoma. However, further studies with a larger number of patients in a more homogeneous disease group are needed to confirm the conclusion.

  16. Horse-collar aurora: A frequent pattern of the aurora in quiet times

    International Nuclear Information System (INIS)

    Hones, E.W. Jr.; Craven, J.D.; Frank, L.A.; Evans, D.S.; Newell, P.T.

    1989-01-01

    Reported here are DE 1 auroral imager observations of an auroral configuration which is given the name ''horse-collar aurora.'' The horse-collar pattern comprises the total area of auroral emissions from a single hemisphere and derives its name from the shape of the emitting area. The pattern is found in images recorded during quiet geomagnetic conditions and is possibly related to the theta aurora, another quiet time configuration of the auroras. This initial report of the DE 1 observations illustrates the horse-collar aurora with a 2-hour images sequence that displays its basic features and shows an example of its evolution into a theta-like auroral pattern. The interplanetary magnetic field was northward during this image sequence and there is some evidence for IMF B/sub y/ influence of the temporal development of the horse-collar pattern. A preliminary statistical analysis found the horse-collar pattern appearing in one-third or more of image sequences recorded during quiet conditions; it did not appear during disturbed conditions. Further study is required to establish more fully the characteristics of the horse-collar aurora and to determine its implications concerning solar wind-magnetosphere coupling when the IMF B/sub z/ is northward. copyright American Geophysical Union 1989

  17. Aurora Mine project - historical resources baseline study

    International Nuclear Information System (INIS)

    Reeves, B.

    1996-01-01

    This volume contains the results of a base line archaeological study of the Aurora Mine Project local study area. It was compiled in support of Syncrude Canada's application to the Alberta Energy and Utilities Board (AEUB) and Alberta Environmental Protection to construct and operate it new Aurora Mine, located northeast of Fort McMurray, Alberta. The objective of this study was to compile, consolidate, review and analyze the reports for the area compiled over the past 22 years in and adjacent to the local study area (LSA), particularly those of now existing and Syncrude projects, and previously proposed Alsands and OSLO projects. The report is a summary of the human history in the area including pre-contact native archaeological sites, past archaeological studies, the Hinterland site pattern, post-contact native traditional sites, oil sands exploration/development related sites and paleontological sites in the subject area, and areas adjacent to it. 150 refs., 5 tabs., 43 figs

  18. Jung's quest for the "Aurora consurgens"

    DEFF Research Database (Denmark)

    Haaning, Aksel

    2014-01-01

    Auriferae (1593); and it raises the question of whether this could be the possible missing link to Jung's subsequent research in Alchemy and Hermetic Philosophy in the years to come. It is argued that here was the beginning of Jung's quest for the Aurora consurgens, the publication of which concludes...... the Mysterium Conuinctionis more than twenty years later. It is further maintained that this choice of the Aurora is a profound expression of Jung's ambition to revitalize the past from within the individual, and helps explain Jung's deep concern with the welfare and future of modern society.......The paper focuses on the year 1929 when Jung published ‘A European commentary’ to Richard Wilhelm's German translation of the Taoist text The Secret of the Golden Flower. This shows that Jung had already started on the track of European alchemy by following up Conrad Waldkirch's preface in Artis...

  19. Aurorae. Firework in the sky. 2. upd. ed.

    International Nuclear Information System (INIS)

    Pfoser, Andreas; Eklund, Tom

    2013-01-01

    Aurorae are fascinating phenomena. As aurora borealis and aurora australis occurring in the polar regions of both earth hemispheres, their incessant color and shape games put people in wonder. The meteorologist Andreas Pfoser explains the physical connections, which lead to the formation of this natural phenomenon. The link with the activity of the sun and the interaction in the earth atmosphere are explained detailedly and understandably. The fantastic recordings, presented in generous horizontal format has collected the Finnish aurora photographer Tom Eklund over a period of time of 14 years. Thereby it succeeded, to document also some events, the origin of which on our daystar were recorded by solar satellites, so that the sequence of events from the solar eruption until the aurora spectacle can be reproduced. The present 2nd edition contains new scientific findings. Additionally numerous aurora pictures were replaced by more actual photos created with modern technology.

  20. Aurora A's functions during mitotic exit: the Guess Who game

    Directory of Open Access Journals (Sweden)

    David eReboutier

    2015-12-01

    Full Text Available Until recently, the knowledge of Aurora A kinase functions during mitosis was limited to pre-metaphase events, particularly centrosome maturation, G2/M transition, and mitotic spindle assembly. However, an involvement of Aurora A in post-metaphase events was also suspected, but not clearly demonstrated due to the technical difficulty to perform the appropriate experiments. Recent developments of both an analog specific version of Aurora A, and of small molecule inhibitors have led to the first demonstration that Aurora A is required for the early steps of cytokinesis. As in pre-metaphase, Aurora A plays diverse functions during anaphase, essentially participating in astral microtubules dynamics and central spindle assembly and functioning. The present review describes the experimental systems used to decipher new functions of Aurora A during late mitosis and situate these functions into the context of cytokinesis mechanisms.

  1. Aurora kinase inhibitors: Progress towards the clinic

    Czech Academy of Sciences Publication Activity Database

    Kollareddy, M.; Zheleva, D.; Dzubak, P.; Brahmkshatriya, Pathik; Lepšík, Martin; Hajduch, M.

    2012-01-01

    Roč. 30, č. 6 (2012), s. 2411-2432 ISSN 0167-6997 Grant - others:GA ČR(CZ) GA301/08/1649; GA ČR(CZ) GD303/09/H048 Program:GA; GD Institutional research plan: CEZ:AV0Z40550506 Keywords : Aurora kinases * cancer * inhibitors Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.498, year: 2012

  2. Electron energy measurements in pulsating auroras

    International Nuclear Information System (INIS)

    McEwan, D.J.; Yee, E.; Whalen, B.A.; Yau, A.W.

    1981-01-01

    Electron spectra were obtained during two rocket flights into pulsating aurora from Southend, Saskatchewan. The first rocket launched at 1143:24 UT on February 15, 1980 flew into an aurora of background intensity 275 R of N 2 + 4278 A and showing regular pulsations with about a 17 s period. Electron spectra of Maxwellian energy distributions were observed with an average E 0 = 1.5 keV, rising to 1.8 keV during the pulsations. There was one-to-one correspondence between the electron energy modulation and the observed optical pulsations. The second rocket, launched at 1009:10 UT on February 23, flew into a diffuse auroral surface of intensity 800 R of N 2 + 4278 A and with somewhat irregular pulsations. The electron spectra were again of Maxwellian energy distribution with an average E 0 = 1.8 keV increasing to 2.1 keV during the pulsations. The results from these flights suggest that pulsating auroras occurring in the morning sector may be quite commonly excited by low energy electrons. The optical pulsations are due to periodic increases in the energy of the electrons with the source of modulation in the vicintiy of the geomagnetic equatorial plane. (auth)

  3. Glow plasma jet - experimental study of a transferred atmospheric pressure glow discharge

    International Nuclear Information System (INIS)

    Guerra-Mutis, Marlon H; U, Carlos V Pelaez; H, Rafael Cabanzo

    2003-01-01

    In this paper we present the experimental study of a glow plasma jet (GPJ) obtained from a transferred atmospheric pressure glow discharge (APGD) operating at 60 Hz. The characterization of the emission spectra for both electrical discharges is presented and the electrical circuit features for APGD generation are discussed. The potentiality of GPJ as a source of active species for depletion of contaminants in liquid hydrocarbon fractions is also established

  4. Plasma Beam Interaction with Negative glow discharge

    International Nuclear Information System (INIS)

    El-Tayeb, H.A.; El-Gamal, H.A.

    2000-01-01

    A miniature coaxial gun has been used to study the effect of the energy spectrum of the ejected plasma on the interaction with negative glow region in a normal glow discharge. The peak discharge current flow between the coaxial electrodes was 5.25 K A as a single pulse with pulse duration of 60 MUs. Investigations are carried out with argon gas at pressure 0.4 Torr. The sheath thickness of the ejected plasma from the coaxial discharge was 6 cm with different densities and energies. The spectrum of electron energy varies between 6 eV and 1 eV, while the electron density varies between 5 x 10 12 cm -3 and 4x10 13 cm -3 . The peak velocity of the ejected plasma was 0. 8 x 10 5 cm sec -1 in the neutral argon atoms. Argon negative glow region used as base plasma has an electron temperature of 2.2 eV and electron density of 6.2 x10 7 cm -3 . It had been found that the velocity of the ejected plasma decreased when it moves in the negative glow region and its mean electron temperature decreased. The results are compared with the theory of beam interaction with cold plasma

  5. Dayside aurorae and their relation to other geophysical phenomena

    International Nuclear Information System (INIS)

    Leontyev, S.V.; Starkov, G.V.; Vorobjev, V.G.; Zverev, V.L.; Feldstein, Ya.I.

    1992-01-01

    Principal morphological peculiarities of auroral luminosity are investigated on the basis of the data from multi-year aurorae observations in day hours at Spitzbergen and Franz Jozef Land. It is shown that in this region the typical forms of aurorae are moving poleward rayed arcs appearing at the equatorward boundary of the auroral oval and disappearing at its pole boundary. Discrete forms of aurorae are located inside a much broader red luminosity band in its equatorward part. Auroral pulsations with a period of 10 50 s are observed in the prenoon sector in a region of much harder precipitations found more equatorward with respect to the daytime red luminosity band. The influence of a B z IMF component upon daytime aurorae is exercised both directly through an equatorward (poleward) shift of daytime aurorae upon decreasing (increasing) B z and via an increase in planetary geomagnetic activity related to the appearance of substorms during which the whole region of the daytime luminosity is shifted to much lower latitudes. A decrease of intensity of daytime aurorae with duration of 5-10 min before the beginning of an expansive phase of a substorm on the night side is detected. The peculiarities of the daytime aurorae dynamics during substorms are also investigated. A scheme of the daytime auroral luminosity distribution is presented. Analytical expressions of the dependence of the daytime aurorae position on IMF are provided. Certain physical mechanisms that can explain the peculiarities of daytime aurorae dynamics are also discussed. (Author)

  6. Genetic diversity in two populations of Limicolaria aurora (Jay, 1839 ...

    African Journals Online (AJOL)

    Limicolaria aurora belongs to the group of land snails commonly called garden snails. This study seeks to use shell morphology and random amplified polymorphic DNA-polymerase chain reaction (RAPDPCR) to examine gross morphological differences in populations of L. aurora from New Bussa (guinea savannah) and ...

  7. Source of the dayside cusp aurora.

    Science.gov (United States)

    Mende, S B; Frey, H U; Angelopoulos, V

    2016-08-01

    Monochromatic all-sky imagers at South Pole and other Antarctic stations of the Automatic Geophysical Observatory chain recorded the aurora in the region where the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites crossed the dayside magnetopause. In several cases the magnetic field lines threading the satellites when mapped to the atmosphere were inside the imagers' field of view. From the THEMIS magnetic field and the plasma density measurements, we were able to locate the position of the magnetopause crossings and map it to the ionosphere using the Tsyganenko-96 field model. Field line mapping is reasonably accurate on the dayside subsolar region where the field is strong, almost dipolar even though compressed. From these coordinated observations, we were able to prove that the dayside cusp aurora of high 630 nm brightness is on open field lines, and it is therefore direct precipitation from the magnetosheath. The cusp aurora contained significant highly structured N 2 + 427.8 nm emission. The THEMIS measurements of the magnetosheath particle energy and density taken just outside the magnetopause compared to the intensity of the structured N 2 + 427.8 nm emissions showed that the precipitating magnetosheath particles had to be accelerated. The most likely electron acceleration mechanism is by dispersive Alfvén waves propagating along the field line. Wave-accelerated suprathermal electrons were seen by FAST and DMSP. The 427.8 nm wavelength channel also shows the presence of a lower latitude hard-electron precipitation zone originating inside the magnetosphere.

  8. Propagation of ionizing waves in glow discharge

    International Nuclear Information System (INIS)

    Suzuki, T.

    1977-01-01

    Ionizing waves were produced along the positive column of a glow discharge in air by applying an impulse voltage to an electrode at one end of the column. Five photomultipliers and three current-sensing coils were used to observe how the waves were affected by the rise time and the magnitude of the applied impulses and by the electron density in the positive column of the glow discharge. It is shown that the speed of the ionizing waves increases with the slope of the applied impulses and with the preexisting electron density. The electron density is augmented about 100--200 times due to the buildup of ionization at the front of the waves. The theory was developed to explain the property of ionizing waves

  9. Source region of aurora kilometric radiation

    International Nuclear Information System (INIS)

    Morioka, Akira; Oya, Hiroshi; Tokumaru, Munetoshi

    1981-01-01

    This paper discusses the source region of aurora kilometric radiation (AKR), and the relation between the particle acceleration region and the polar ionosphere. The observation was made by the satellite 'Jikiken'. The AKR can be transferred to Jikiken without any interception, when the magnetic latitude of the apogee of the satellite is low. The spectra taken in June, 1980, were analyzed. The observed spectra showed the source regions of the AKR were in the aurora bands of the north and south poles. One example showed that the 200 kHz component of AKR from both poles showed the similar behavior, and another example showed that the AKR spectra from both poles showed different behavior. The altitude distribution of source regions was able to be obtained. The altitude of AKR-A was in the range between 6200 and 12000 km, and that of AKR-B was in the range of 3500 and 5200 km. The source of AKR-A was identified as that in the south hemisphere, and that of AKR-B in the north hemisphere. The asymmetric spectra of AKR-A and B showed that the spread and intensity of the electric field along magnetic lines generated above the polar ionosphere were related with the conditions of the ionosphere. (Kato, T.)

  10. Electron beam generation in high voltage glow discharges

    International Nuclear Information System (INIS)

    Rocca, J.J.; Szapiro, B.; Murray, C.

    1989-01-01

    The generation of intense CW and pulsed electron beams in glow discharges in reviewed. Glow discharge electron guns operate at a pressure of the order of 1 Torr and often have an advantage in applications that require a broad area electron beam in a gaseous atmosphere, such as laser excitation and some aspects of materials processing. Aspects of electron gun design are covered. Diagnostics of the high voltage glow discharges including the electric field distribution mapped by Doppler free laser spectroscopy, and plasma density and electron temperature measurements of the electron yield of different cathode materials under glow discharge conditions are presented

  11. Simultaneous Aurora-A/STK15 overexpression and centrosome amplification induce chromosomal instability in tumour cells with a MIN phenotype

    Directory of Open Access Journals (Sweden)

    Schillaci Tiziana

    2007-11-01

    results show that centrosome amplification alone is not sufficient to induce chromosomal instability in colon cancer cells with a MIN phenotype. Alternatively, centrosome amplification has to be associated with alterations in genes regulating mitosis progression such as Aurora-A/STK15 to trigger CIN.

  12. Storm-time Convection Dynamics Viewed from Optical Auroras: from Streamer to Patchy Pulsating Aurora

    Science.gov (United States)

    Yang, B.; Donovan, E.; Liang, J.; Grono, E.

    2016-12-01

    In a series of statistical and event studies we have demonstrated that the motion of patches in regions of Patchy Pulsating Aurora (PPA) is very close to if not exactly convection. Thus, 2D maps of PPA motion provides us the opportunity to remote sense magnetospheric convection with relatively high space and time resolution, subject to uncertainties associated with mapping between the ionosphere and magnetosphere. In this study, we use THEMIS ASI aurora observations (streamers and patchy pulsating aurora) combined with SuperDARN convection measurements, Swarm ion drift velocity measurements, and RBSP electric field measurements to explore the convection dynamics in storm time. From 0500 UT to 0600 UT on March 19 2015, convection observations across 5 magnetic local time (MLT) inferred from the motion of PPA patches and SuperDARN measurements show that a westward SAPS (Subauroral Polarized Streams) enhancement occurs after an auroral streamer. This suggests that plasma sheet fast flows can affect the inner magnetospheric convection, and possibly trigger very fast flows in the inner magnetosphere.

  13. Global magnetic anomaly and aurora of Neptune

    International Nuclear Information System (INIS)

    Cheng, A.F.

    1990-01-01

    The large offset and tilt of Neptune's dipole magnetic field combine to create a global magnetic anomaly, analogous to but much more important than Earth's South Atlantic Anomaly. Energetic particle precipitation loss within the Neptune anomaly creates atmospheric drift shadows within which particle fluxes are greatly reduced. The energetic particle dropout observed by Voyager near closest approach occurred near the predicted times when Voyager passed within the atmospheric drift shadow. Extremely soft, structured bursts of ions and electrons within the drift shadow may result from plasma wave-induced pitch angle scattering of trapped particles confined near the magnetic equator. The dropout does not necessarily imply that Voyager passed through an Earth-like discrete auroral zone, as earlier reported. The ion and electron fluxes observed within the dropout period correspond to particles that must precipitate to Neptune's atmosphere within the anomaly region. This anomaly precipitation can account for a major portion of the ultraviolet emissions previously identified as Neptune aurora

  14. The Aurora accelerator's triggered oil switch

    International Nuclear Information System (INIS)

    Weidenheimer, D.M.; Pereira, N.R.; Judy, D.C.; Stricklett, K.L.

    1993-01-01

    Achieving a radiation pulse with 15 ns risetime using all four of the Aurora accelerator's Blumlein pulse-forming lines demands synchronization of the Blumleins to within 10 ns (in addition to a 15 ns risetime for a single line). Timing of each Blumlein is controlled by a triggered 12 MV oil switch. A smaller-than-customary trigger electrode makes the switching time more reproducible. Time-resolved photography of the oil arcs suggests that triggering occurs simultaneously around the sharp edge of the trigger electrode, perhaps with small deviations that grow into the most prominent arcs characteristically seen in open-shutter photographs. However, many smaller arcs that are usually overlooked in open-shutter pictures may contribute to current conduction in a closed switch

  15. A Panchromatic View of Brown Dwarf Aurorae

    Energy Technology Data Exchange (ETDEWEB)

    Pineda, J. Sebastian [University of Colorado Boulder, Laboratory for Atmospheric and Space Physics, 3665 Discovery Drive, Boulder CO, 80303 (United States); Hallinan, Gregg; Kao, Melodie M. [California Institute of Technology, Department of Astronomy, 1200 E. California Avenue, Pasadena CA, 91125 (United States)

    2017-09-01

    Stellar coronal activity has been shown to persist into the low-mass star regime, down to late M-dwarf spectral types. However, there is now an accumulation of evidence suggesting that at the end of the main sequence, there is a transition in the nature of the magnetic activity from chromospheric and coronal to planet-like and auroral, from local impulsive heating via flares and MHD wave dissipation to energy dissipation from strong large-scale magnetospheric current systems. We examine this transition and the prevalence of auroral activity in brown dwarfs through a compilation of multiwavelength surveys of magnetic activity, including radio, X-ray, and optical. We compile the results of those surveys and place their conclusions in the context of auroral emission as a consequence of large-scale magnetospheric current systems that accelerate energetic electron beams and drive the particles to impact the cool atmospheric gas. We explore the different manifestations of auroral phenomena, like H α , in brown dwarf atmospheres and define their distinguishing characteristics. We conclude that large-amplitude photometric variability in the near-infrared is most likely a consequence of clouds in brown dwarf atmospheres, but that auroral activity may be responsible for long-lived stable surface features. We report a connection between auroral H α emission and quiescent radio emission in electron cyclotron maser instability pulsing brown dwarfs, suggesting a potential underlying physical connection between quiescent and auroral emissions. We also discuss the electrodynamic engines powering brown dwarf aurorae and the possible role of satellites around these systems both to power the aurorae and seed the magnetosphere with plasma.

  16. Research Ship Aurora Australis Underway Meteorological Data, Quality Controlled

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Research Ship Aurora Australis Underway Meteorological Data (delayed ~10 days for quality control) are from the Shipboard Automated Meteorological and Oceanographic...

  17. Identifying the warm glow effect in contingent valuation

    NARCIS (Netherlands)

    Nunes, P.A.L.D.; Schokkaert, E.

    2003-01-01

    This paper reports the results from a contingent valuation study designed to investigate the influence of warm glow in willingness to pay (WTP) responses. Interindividual differences in warm glow motivation are measured through a factor analysis, performed on a list of attitudinal items. The

  18. Acting green elicits a literal warm glow

    Science.gov (United States)

    Taufik, Danny; Bolderdijk, Jan Willem; Steg, Linda

    2015-01-01

    Environmental policies are often based on the assumption that people only act environmentally friendly if some extrinsic reward is implicated, usually money. We argue that people might also be motivated by intrinsic rewards: doing the right thing (such as acting environmentally friendly) elicits psychological rewards in the form of positive feelings, a phenomenon known as warm glow. Given the fact that people's psychological state may affect their thermal state, we expected that this warm glow could express itself quite literally: people who act environmentally friendly may perceive the temperature to be higher. In two studies, we found that people who learned they acted environmentally friendly perceived a higher temperature than people who learned they acted environmentally unfriendly. The underlying psychological mechanism pertains to the self-concept: learning you acted environmentally friendly signals to yourself that you are a good person. Together, our studies show that acting environmentally friendly can be psychologically rewarding, suggesting that appealing to intrinsic rewards can be an alternative way to encourage pro-environmental actions.

  19. Glow discharge based device for solving mazes

    Energy Technology Data Exchange (ETDEWEB)

    Dubinov, Alexander E., E-mail: dubinov-ae@yandex.ru; Mironenko, Maxim S.; Selemir, Victor D. [Russian Federal Nuclear Center − All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation); Sarov Institute of Physics and Technology (SarFTI) of National Research Nuclear University “MEPhI,” Sarov, Nizhni Novgorod region 607188 (Russian Federation); Maksimov, Artem N.; Pylayev, Nikolay A. [Russian Federal Nuclear Center − All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation)

    2014-09-15

    A glow discharge based device for solving mazes has been designed and tested. The device consists of a gas discharge chamber and maze-transformer of radial-azimuth type. It allows changing of the maze pattern in a short period of time (within several minutes). The device has been tested with low pressure air. Once switched on, a glow discharge has been shown to find the shortest way through the maze from the very first attempt, even if there is a section with potential barrier for electrons on the way. It has been found that ionization waves (striations) can be excited in the maze along the length of the plasma channel. The dependancy of discharge voltage on the length of the optimal path through the maze has been measured. A reduction in discharge voltage with one or two potential barriers present has been found and explained. The dependency of the magnitude of discharge ignition voltage on the length of the optimal path through the maze has been measured. The reduction of the ignition voltage with the presence of one or two potential barriers has been observed and explained.

  20. Low latitude aurorae on October 21, 1989, 2

    International Nuclear Information System (INIS)

    Kuwashima, Masayuki; Tsunomura, Satoru; Uwai, Tetsuya; Saito, Buniti; Takahasi, Tosiyasu; Kiyama, Yositaka.

    1990-01-01

    Appearance of low-latitude aurorae was seen in Hokkaido, a northern district in Japan, on October 21 and November 17, 1989, during severe magnetic storms. Some characteristics of the associated magnetic variations are shown and discussed in the present short report. The appearance of low-latitude aurora events was found during a time interval of a sharp H-component increase succeeding to the maximum development of the storm time ring current. The cause of the increase in the H-component seems to be associated with the bay disturbance because Pi2 magnetic pulsations were always associated with the low-latitude aurora event. The period of an aurora associated Pi2 event is shorter (40-60 seconds) than that of a usual Pi2 event (100 seconds). During the main phase of geomagnetic storm on October 21, optical and spectroscopic observations of low latitude aurora were made with an airglow-photometer, spectrograph and an all sky camera at Niigata (latitude 37.7degN, longitude 138.8degE and geomagnetic latitude 27.7degN). Spectra of low latitude aurorae observed in Niigata are given and discussed. A model for the main part of the auroral emission is also presented. (N.K.)

  1. Pre-glow phenomenon origin and its scaling for ECRIS

    International Nuclear Information System (INIS)

    Izotov, I.; Sidorov, A.; Skalyga, V.; Zorin, V.

    2012-01-01

    Pre-glow is the multi-charged ion current burst that may occur at the beginning of the beam pulse. Pre-glow effect investigation is one of topical directions of ECR ion sources development at present. Pre-glow is of interest for efficient short-pulsed multicharged ion source creation. Particularly, such source of intense beams of short living radioactive isotopes multi-charged ions is one of key elements in 'Beta-Beam' European project. The use of Pre-glow-generating regime of an ECRIS operation is a promising way of pulsed high-intense multi-charged ion beams production with much shorter edges in comparison with usual operation regime. Numerical simulations made with the updated theoretical model allow authors to propose more physical and intuitive explanations of Pre-glow phenomenon origins. The obtained dependences of Pre-glow characteristics on experimental conditions offer a scaling for a wide range of ECRIS. The propose scaling demonstrates that an ECR source with plasma heating by radiation at frequency of 37 GHz and higher seems to be the most effective in terms of currents, pre-glow intensity and mean ion charge. The paper is followed by the slides of the presentation

  2. Reconstruction of thermally quenched glow curves in quartz

    International Nuclear Information System (INIS)

    Subedi, Bhagawan; Polymeris, George S.; Tsirliganis, Nestor C.; Pagonis, Vasilis; Kitis, George

    2012-01-01

    The experimentally measured thermoluminescence (TL) glow curves of quartz samples are influenced by the presence of the thermal quenching effect, which involves a variation of the luminescence efficiency as a function of temperature. The real shape of the thermally unquenched TL glow curves is completely unknown. In the present work an attempt is made to reconstruct these unquenched glow curves from the quenched experimental data, and for two different types of quartz samples. The reconstruction is based on the values of the thermal quenching parameter W (activation energy) and C (a dimensionless constant), which are known from recent experimental work on these two samples. A computerized glow-curve deconvolution (CGCD) analysis was performed twice for both the reconstructed and the experimental TL glow curves. Special attention was paid to check for consistency between the results of these two independent CGCD analyses. The investigation showed that the reconstruction attempt was successful, and it is concluded that the analysis of reconstructed TL glow curves can provide improved values of the kinetic parameters E, s for the glow peaks of quartz. This also leads to a better evaluation of the half-lives of electron trapping levels used for dosimetry and luminescence dating.

  3. Dancing Lights: Creating the Aurora Story

    Science.gov (United States)

    Wood, E. L.; Cobabe-Ammann, E. A.

    2009-12-01

    Science tells a story about our world, our existence, our history, and the larger environment our planet occupies. Bearing this in mind, we created a series of lessons for 3rd-5th grades using a cross-disciplinary approach to teaching about the aurora by incorporating stories, photos, movies, and geography into the science in order to paint a broad picture and answer the question, “why do we care?” The fundamental backbone of the program is literacy. Students write and illustrate fiction and non-fiction work, poetry, and brochures that solidify both language arts skills and science content. In a time when elementary teachers relegate science to less than one hour per week, we have developed a novel science program that can be easily integrated with other topics during the typical school day to increase the amount of science taught in a school year. We are inspiring students to take an interest in the natural world with this program, a stepping-stone for larger things.

  4. Multiplicity detector using a glow-discharge memory

    International Nuclear Information System (INIS)

    Mulera, T.; Elola, M.; Perez-Mendez, V.; Wiedenbeck, P.

    1981-04-01

    It has been proposed to eliminate the x-y cor relation ambiguities introduced by multiple tracks in a wire chamber by using the chamber itself as a memory. Hits in the chamber itself ignite glow discharges storing the x-y location of the hits in a correlated fashion. Glow ignition may be achieved by employing a multi-step avalanche chamber above a memory gap. Correlation is maintained during readout by successively pulsing each hit wire in one coordinate and sensing transmissions through glows in the other coordinate. Prototypes constructed by the authors are discussed along with the associated high voltage and readout systems

  5. Aurora Borealis, A Painting by Frederic Edwin Church

    Science.gov (United States)

    Love, J. J.

    2015-12-01

    This year marks the sesquicentennial anniversary of the end of the American Civil War. In 1865, the same year as the War's end, the great American landscape artist, Frederic Edwin Church, unveiled Aurora Borealis, a painting that depicts a fantastic, far-northern place, an auroral arch stretched across a quiet night-time sky, above dark mountains and a frozen sea. Church was born in Connecticut, lived in New York, and traveled to Labrador; he would have often seen the northern lights. Church might have also been influenced by the spectacular displays of aurora that were caused by some unusually intense magnetic storms in 1859. Aurora Borealis can certainly be interpreted in terms of 19th-century romanticism, scientific philosophy, and Arctic missions of exploration, all subjects of interest to Church. As with so many of his paintings, Church's meticulous attention to detail in Aurora Borealis reveals his deep admiration of nature. But his depiction of auroral light is a curious and possibly intentional departure from natural verisimilitude. Some art historians have suggested that Church painted Aurora Borealis as a subdued tribute to the end of the Civil War, with the drapery of auroral light forming an abstract representation of the American flag. If so, then colors of the flag have been unfurled across a cold and barren landscape, not in extravagant celebration, but in somber recognition of the reality of post-war desolation and an uncertain future.

  6. Radio-frequency glow discharge spectrometry: A critical review

    International Nuclear Information System (INIS)

    Winchester, Michael R.; Payling, Richard

    2004-01-01

    This paper presents a critical review of analytical radio frequency glow discharge spectrometry (rf-GDS). The historical foundations of rf-GDS are described, and current knowledge of the fundamental physics of analytical rf glow discharges is discussed. Additionally, instrumentation, methodologies, and applications of rf glow discharge optical emission spectrometry (rf-GDOES) and mass spectrometry (rf-GDMS) are reviewed. Although other rf-GDS techniques have appeared [e.g. rf glow discharge atomic absorption spectrophotometry (rf-GDAAS)], the emphasis is placed upon rf-GDOES and rf-GDMS, because they have received by far the most interest from analytical chemical metrologists. This review also provides explanations of some developments that are needed for further progress in the field of analytical rf-GDS

  7. Glow phenomenon surrounding the vertical stabilizer and OMS pods

    Science.gov (United States)

    1994-01-01

    This 35mm frame, photographed as the Space Shuttle Columbia was orbiting Earth during a 'night' pass, documents the glow phenomenon surrounding the vertical stabilizer and the Orbital Maneuvering System (OMS) pods of the spacecraft.

  8. Ionospheric response to particle precipitation within aurora

    International Nuclear Information System (INIS)

    Wahlund, J.E.

    1992-03-01

    The aurora is just the visible signature of a large number of processes occurring in a planetary ionosphere as a response to energetic charged particles falling in from the near-empty space far above the planetary atmosphere. This thesis, based on measurements using the EISCAT incoherent scatter radar system in northern Scandinavia, discusses ionospheric response processes and especially a mechanism leading to atmospheric gas escape from a planet. One of the most spectacular events in the high latitude atmosphere on earth are the 'auroral arcs' - dynamic rayed sheets of light. An investigation of the conditions of the ionosphere surrounding auroral arcs shows that strong field-aligned bulk ion outflows appear in the topside ionosphere which account for a large fraction of the escape of atmospheric oxygen from earth. Four different additional ionospheric responses are closely related to this ion outflow; 1. enhanced electron temperatures of several thousand Kelvin above an altitude of about 250 km, 2. enhanced ionization around an altitude of 200 km corresponding to electron precipitation with energies of a few hundred eV, 3. the occurrence of naturally enhanced ion acoustic fluctuations seen in the radar spectrum, most likely produced by an ion-ion two-stream instability, and 4. upward directed field-aligned currents partly carried by the outflowing ions. From these observations, it is suggested that the energy dissipation into the background plasma through Joule heating, the production of a few hundred eV energetic run-away electrons, and strong ion outflows are partly produced by the simultaneous presence of ion acoustic turbulence and field-aligned currents above auroral arcs. (20 refs.) (au)

  9. Optical tomography of the aurora and EISCAT

    Directory of Open Access Journals (Sweden)

    H. U. Frey

    1998-10-01

    Full Text Available Tomographic reconstruction of the three-dimensional auroral arc emission is used to obtain vertical and horizontal distributions of the optical auroral emission. Under the given experimental conditions with a very limited angular range and a small number of observers, algebraic reconstruction methods generally yield better results than transform techniques. Different algebraic reconstruction methods are tested with an auroral arc model and the best results are obtained with an iterative least-square method adapted from emission-computed tomography. The observation geometry used during a campaign in Norway in 1995 is tested with the arc model and root-mean-square errors, to be expected under the given geometrical conditions, are calculated. Although optimum geometry was not used, root-mean-square errors of less than 2% for the images and of the order of 30% for the distribution could be obtained. The method is applied to images from real observations. The correspondence of original pictures and projections of the reconstructed volume is discussed, and emission profiles along magnetic field lines through the three-dimensionally reconstructed arc are calibrated into electron density profiles with additional EISCAT measurements. Including a background profile and the temporal changes of the electron density due to recombination, good agreement can be obtained between measured profiles and the time-sequence of calculated profiles. These profiles are used to estimate the conductivity distribution in the vicinity of the EISCAT site. While the radar can only probe the ionosphere along the radar beam, the three-dimensional tomography enables conductivity estimates in a large area around the radar site.Key words. Tomography · Aurora · EISCAT · Ionosphere · Conductivity

  10. Optical tomography of the aurora and EISCAT

    Directory of Open Access Journals (Sweden)

    H. U. Frey

    Full Text Available Tomographic reconstruction of the three-dimensional auroral arc emission is used to obtain vertical and horizontal distributions of the optical auroral emission. Under the given experimental conditions with a very limited angular range and a small number of observers, algebraic reconstruction methods generally yield better results than transform techniques. Different algebraic reconstruction methods are tested with an auroral arc model and the best results are obtained with an iterative least-square method adapted from emission-computed tomography. The observation geometry used during a campaign in Norway in 1995 is tested with the arc model and root-mean-square errors, to be expected under the given geometrical conditions, are calculated. Although optimum geometry was not used, root-mean-square errors of less than 2% for the images and of the order of 30% for the distribution could be obtained. The method is applied to images from real observations. The correspondence of original pictures and projections of the reconstructed volume is discussed, and emission profiles along magnetic field lines through the three-dimensionally reconstructed arc are calibrated into electron density profiles with additional EISCAT measurements. Including a background profile and the temporal changes of the electron density due to recombination, good agreement can be obtained between measured profiles and the time-sequence of calculated profiles. These profiles are used to estimate the conductivity distribution in the vicinity of the EISCAT site. While the radar can only probe the ionosphere along the radar beam, the three-dimensional tomography enables conductivity estimates in a large area around the radar site.

    Key words. Tomography · Aurora · EISCAT · Ionosphere · Conductivity

  11. On the distribution of plasma parameters in RF glow discharge

    International Nuclear Information System (INIS)

    Ning Cheng; Liu Zuli; Liu Donghui; Han Caiyuan.

    1993-01-01

    A self-consistent numerical model based on the two-fluid equations for describing the transport of charged particles in the RF glow discharge is presented. For a plasma generator filled with low-pressure air and parallel-plate electrodes, the model is numerical solved. The space-time distribution of parameters and the spatial distribution of some time-averaged parameters in plasma, which show the physical picture of the RF glow discharge, are obtained

  12. tgcd: An R package for analyzing thermoluminescence glow curves

    Directory of Open Access Journals (Sweden)

    Jun Peng

    2016-01-01

    Full Text Available Thermoluminescence (TL glow curves are widely used in dosimetric studies. Many commercial and free-distributed programs are used to deconvolute TL glow curves. This study introduces an open-source R package tgcd to conduct TL glow curve analysis, such as kinetic parameter estimation, glow peak simulation, and peak shape analysis. TL glow curves can be deconvoluted according to the general-order empirical expression or the semi-analytical expression derived from the one trap-one recombination center (OTOR model based on the Lambert W function by using a modified Levenberg–Marquardt algorithm from which any of the parameters can be constrained or fixed. The package provides an interactive environment to initialize parameters and offers an automated “trial-and-error” protocol to obtain optimal fit results. First-order, second-order, and general-order glow peaks (curves are simulated according to a number of simple kinetic models. The package was developed using a combination of Fortran and R programming languages to improve efficiency and flexibility.

  13. TV morphology of some episodes of pulsating auroras

    International Nuclear Information System (INIS)

    Vallance Jones, A.; Gattinger, R.L.

    1981-01-01

    Sets of all-sky TV images of pulsating auroras obtained during the displays through which the sounding rockets of the Pulsating Aurora Campaign were fired are presented and discussed. It is emphasized that these displays are considerably more complex and variable than might seem to be the case on the basis of zenith photometer records. The pulsation modulation pattern was observed to be travelling westward during the first flight; later in the same display this apparent motion ceased. For the second flight the pulsation modulation pattern was almost stationary. (auth)

  14. Relative drift between black aurora and the ionospheric plasma

    Directory of Open Access Journals (Sweden)

    E. M. Blixt

    2005-07-01

    Full Text Available Black auroras are recognized as spatially well-defined regions within uniform diffuse aurora where the optical emission is significantly reduced. Although a well studied phenomenon, there is no generally accepted theory for black auroras. One theory suggests that black regions are formed when energetic magnetospheric electrons no longer have access to the loss cone. If this blocking mechanism drifts with the source electron population in the magnetosphere, black auroras in the ionosphere should drift eastward with a velocity that increases with the energy of the precipitating electrons in the surrounding aurora, since the gradient-B curvature drift is energy dependent. It is the purpose of this paper to test this hypothesis. To do so we have used simultaneous measurements by the European Incoherent Scatter (EISCAT radar and an auroral TV camera at Tromsø, Norway. We have analyzed 8 periods in which a black aurora occurred frequently to determine their relative drift with respect to the ionospheric plasma. The black aurora was found to drift eastward with a velocity of 1.5–4km/s, which is in accordance with earlier observations. However, one case was found where a black patch was moving westward, this being the first report of such behaviour in the literature. In general, the drift was parallel to the ionospheric flow but at a much higher velocity. This suggests that the generating mechanism is not of ionospheric origin. The characteristic energy of the precipitating electron population was estimated through inversion of E-region plasma density profiles. We show that the drift speed of the black patches increased with the energy of the precipitating electrons in a way consistent with the gradient-B curvature drift, suggesting a magnetospheric mechanism for the black aurora. As expected, a comparison of the drift speeds with a rudimentary dipole field model of the gradient-B curvature drift speed only yields order-of-magnitude agreement, which

  15. Navigation GPS/GLONASS in the Arctic and aurora

    Directory of Open Access Journals (Sweden)

    Chernouss S. A.

    2016-12-01

    Full Text Available The correspondence of the time-spatial distribution of the radiances of the aurora oval and time-spatial changes in the parameters of the navigation satellites' signal has been shown. For this aim the experimental data on the regional and local heterogeneities of the Total Electron Content (or TEC and the data on the signal delays in the polar ionosphere have been analyzed. Using the data concerning aurora as the indicator of disturbances in the work of the GPS/GLONASS systems can give the opportunity to increase considerably the accuracy of positioning in the Arctic with the help of satellite navigation systems (SNS.

  16. Phenotypic Screening Approaches to Develop Aurora Kinase Inhibitors: Drug Discovery Perspectives.

    Science.gov (United States)

    Marugán, Carlos; Torres, Raquel; Lallena, María José

    2015-01-01

    Targeting mitotic regulators as a strategy to fight cancer implies the development of drugs against key proteins, such as Aurora-A and -B. Current drugs, which target mitosis through a general mechanism of action (stabilization/destabilization of microtubules), have several side effects (neutropenia, alopecia, and emesis). Pharmaceutical companies aim at avoiding these unwanted effects by generating improved and selective drugs that increase the quality of life of the patients. However, the development of these drugs is an ambitious task that involves testing thousands of compounds through biochemical and cell-based assays. In addition, molecules usually target complex biological processes, involving several proteins and different molecular pathways, further emphasizing the need for high-throughput screening techniques and multiplexing technologies in order to identify drugs with the desired phenotype. We will briefly describe two multiplexing technologies [high-content imaging (HCI) and flow cytometry] and two key processes for drug discovery research (assay development and validation) following our own published industry quality standards. We will further focus on HCI as a useful tool for phenotypic screening and will provide a concrete example of HCI assay to detect Aurora-A or -B selective inhibitors discriminating the off-target effects related to the inhibition of other cell cycle or non-cell cycle key regulators. Finally, we will describe other assays that can help to characterize the in vitro pharmacology of the inhibitors.

  17. Phenotypic screening approaches to develop Aurora kinase inhibitors: Drug Discovery perspectives

    Directory of Open Access Journals (Sweden)

    Carlos eMarugán

    2016-01-01

    Full Text Available Targeting mitotic regulators as a strategy to fight cancer implies the development of drugs against key proteins such as Aurora A and B. Current drugs which target mitosis through a general mechanism of action (stabilization/destabilization of microtubules, have several side effects (neutropenia, alopecia, emesis. Pharmaceutical companies aim at avoiding these unwanted effects by generating improved and selective drugs that increase the quality of life of the patients. However, the development of these drugs is an ambitious task that involves testing thousands of compounds through biochemical and cell-based assays. In addition, molecules usually target complex biological processes, involving several proteins and different molecular pathways, further emphasizing the need for high-throughput screening techniques and multiplexing technologies in order to identify drugs with the desired phenotype.We will briefly describe two multiplexing technologies (high-content imaging, microarrays and flow cytometry and two key processes for drug discovery research (assay development and validation following our own published industry quality standards. We will further focus on high-content imaging as a useful tool for phenotypic screening and will provide a concrete example of high-content imaging assay to detect Aurora A or B selective inhibitors discriminating the off-target effects related to inhibition of other cell cycle or non-cell cycle key regulators. Finally, we will describe other assays that can help to characterize the in vitro pharmacology of the inhibitors.

  18. Specific primary sequence requirements for Aurora B kinase-mediated phosphorylation and subcellular localization of TMAP during mitosis.

    Science.gov (United States)

    Kim, Hyun-Jun; Kwon, Hye-Rim; Bae, Chang-Dae; Park, Joobae; Hong, Kyung U

    2010-05-15

    During mitosis, regulation of protein structures and functions by phosphorylation plays critical roles in orchestrating a series of complex events essential for the cell division process. Tumor-associated microtubule-associated protein (TMAP), also known as cytoskeleton-associated protein 2 (CKAP2), is a novel player in spindle assembly and chromosome segregation. We have previously reported that TMAP is phosphorylated at multiple residues specifically during mitosis. However, the mechanisms and functional importance of phosphorylation at most of the sites identified are currently unknown. Here, we report that TMAP is a novel substrate of the Aurora B kinase. Ser627 of TMAP was specifically phosphorylated by Aurora B both in vitro and in vivo. Ser627 and neighboring conserved residues were strictly required for efficient phosphorylation of TMAP by Aurora B, as even minor amino acid substitutions of the phosphorylation motif significantly diminished the efficiency of the substrate phosphorylation. Nearly all mutations at the phosphorylation motif had dramatic effects on the subcellular localization of TMAP. Instead of being localized to the chromosome region during late mitosis, the mutants remained associated with microtubules and centrosomes throughout mitosis. However, the changes in the subcellular localization of these mutants could not be completely explained by the phosphorylation status on Ser627. Our findings suggest that the motif surrounding Ser627 ((625) RRSRRL (630)) is a critical part of a functionally important sequence motif which not only governs the kinase-substrate recognition, but also regulates the subcellular localization of TMAP during mitosis.

  19. Featured Image: Identifying a Glowing Shell

    Science.gov (United States)

    Kohler, Susanna

    2018-05-01

    New nebulae are being discovered and classified every day and this false-color image reveals one of the more recent objects of interest. This nebula, IPHASX J210204.7+471015, was recently imaged by the Andalucia Faint Object Spectrograph and Camera mounted on the 2.5-m Nordic Optical Telescope in La Palma, Spain. J210204 was initially identified as a possible planetary nebula a remnant left behind at the end of a red giants lifetime. Based on the above imaging, however, a team of authors led by Martn Guerrero (Institute of Astrophysics of Andalusia, Spain) is arguing that this shell of glowing gas was instead expelled around a classical nova. In a classical nova eruption, a white dwarf and its binary companion come very close together, and mass transfers to form a thin atmosphere of hydrogen around the white dwarf. When this hydrogen suddenly ignites in runaway fusion, this outer atmosphere can be expelled, forming a short-lived nova remnant which is what Guerrero and collaborators think were seeing with J210204. If so, this nebula can reveal information about the novathat caused it. To find out more about what the authors learned from this nebula, check out the paper below.CitationMartn A. Guerrero et al 2018 ApJ 857 80. doi:10.3847/1538-4357/aab669

  20. Oxygen negative glow: reactive species and emissivity

    International Nuclear Information System (INIS)

    Sahli, Khaled

    1991-01-01

    This research thesis addresses the study of a specific type of oxygen plasma created by electron beams (1 keV, 20 mA/cm"2), negative glow of a luminescent discharge in abnormal regime. The objective is to test the qualities of this plasma as source of two 'active' species of oxygen (singlet molecular oxygen and atomic oxygen) which are useful in applications. The experiment mainly bears on the use of VUV (120 to 150 nm) absorption spectroscopy measurements of concentrations of these both species, and on the recording of plasma emissivity space profiles in the visible region (450 to 850 nm). It appears that low concentrations of singlet oxygen definitely exclude this type of discharge for iodine laser applications. On the contrary, concentrations measured for atomic oxygen show it is a good candidate for the oxidation of large surfaces by sheets of beams. The satisfying comparison of emissivity results with a published model confirm the prevailing role of fast electrons, and gives evidence of an important effect of temperature: temperature can reach 1000 K, and this is in agreement with the presented measurement [fr

  1. Antitumor activity of TY-011 against gastric cancer by inhibiting Aurora A, Aurora B and VEGFR2 kinases

    Directory of Open Access Journals (Sweden)

    Wang Liu

    2016-11-01

    Full Text Available Abstract Background Overexpression of Aurora A and B has been reported in a wide range of tumor types, including gastric cancer. Anti-angiogenesis has been considered as an important therapeutic modality in advanced gastric cancer. Here we identified a novel compound TY-011 with promising antitumor activity by targeting mitotic kinases (Aurora A and B and angiogenic receptor tyrosine kinase (VEGFR2. Methods HTRF® KinEASE™ assay was used to detect the effect of TY-011 against Aurora A, Aurora B and VEGFR2 activities. Docking simulation study was performed to predict the binding mode of TY-011 with Aurora A and B kinases. CCK-8 assay was used to test cell growth. Cell cycle and cell apoptosis was analyzed by flow cytometry. Gastric cancer cell xenograft mouse models were used for in vivo study. TUNEL kit was used to determine the apoptosis of tumor tissues. Immunohistochemistry analysis and HUVEC tube formation assay were performed to determine the anti-angiogenesis ability. Immunofluorescence and western blot were used to test protein expression. Results TY-011 was identified as a potential Aurora A and B inhibitor by HTRF® KinEASE™ assay. It effectively inhibited cellular Aurora A and B activities in a concentration-dependent manner. TY-011 occupied the ATP-binding site of both Aurora A and B kinases. TY-011 demonstrated prominent inhibitory effects on proliferation of gastric cancer cells. TY-011 treatment induced an obvious accumulation of cells at G2/M phase and a modest increase of cells with >4 N DNA content, which then underwent apoptosis. Meaningfully, orally administration of TY-011 demonstrated superior efficacy against the tumor growth in gastric cancer cell xenograft, with ~90% inhibition rate and 100% tumor regression at 9 mg/kg dose, and TY-011 did not affect the body weight of mice. Interestingly, we observed that TY-011 also antagonized tumor angiogenesis by targeting VEGFR2 kinase. Conclusions These results indicate that

  2. Altered expression of Aurora kinases in Arabidopsis results in aneu- and polyploidization.

    Science.gov (United States)

    Demidov, Dmitri; Lermontova, Inna; Weiss, Oda; Fuchs, Joerg; Rutten, Twan; Kumke, Katrin; Sharbel, Timothy F; Van Damme, Daniel; De Storme, Nico; Geelen, Danny; Houben, Andreas

    2014-11-01

    Aurora is an evolutionary conserved protein kinase family involved in monitoring of chromosome segregation via phosphorylation of different substrates. In plants, however, the involvement of Aurora proteins in meiosis and in sensing microtubule attachment remains to be proven, although the downstream components leading to the targeting of spindle assembly checkpoint signals to anaphase-promoting complex have been described. To analyze the three members of Aurora family (AtAurora1, -2, and -3) of Arabidopsis we employed different combinations of T-DNA insertion mutants and/or RNAi transformants. Meiotic defects and the formation of unreduced pollen were revealed including plants with an increased ploidy level. The effect of reduced expression of Aurora was mimicked by application of the ATP-competitive Aurora inhibitor II. In addition, strong overexpression of any member of the AtAurora family is not possible. Only tagged or truncated forms of Aurora kinases can be overexpressed. Expression of truncated AtAurora1 resulted in a high number of aneuploids in Arabidopsis, while expression of AtAurora1-TAPi construct in tobacco resulted in 4C (possible tetraploid) progeny. In conclusion, our data demonstrate an essential role of Aurora kinases in the monitoring of meiosis in plants. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

  3. Nutritive potentials and utilization of garden snail (Limicolaria aurora ...

    African Journals Online (AJOL)

    AJB SERVER

    2006-10-16

    Oct 16, 2006 ... The possibility of using garden snail (Limicolaria aurora) meat meal as a protein source in fish feeds was tested in ... garden snail meat meal was used to replace fish meal at 0%, (control diet), 25, 50, 75 and 100% inclusion ..... Randall DJ, Brett JR (eds) Fish Physiology, Academic Press, NY 8: 279-352,.

  4. Nutritive potentials and utilization of garden snail (Limicolaria aurora ...

    African Journals Online (AJOL)

    The possibility of using garden snail (Limicolaria aurora) meat meal as a protein source in fish feeds was tested in Clarias gariepinus fingerlings. Five isonitrogenous (43% crude protein) diets in which garden snail meat meal was used to replace fish meal at 0%, (control diet), 25, 50, 75 and 100% inclusion levels were used ...

  5. Canine osteosarcoma cells exhibit resistance to aurora kinase inhibitors.

    Science.gov (United States)

    Cannon, C M; Pozniak, J; Scott, M C; Ito, D; Gorden, B H; Graef, A J; Modiano, J F

    2015-03-01

    We evaluated the effect of Aurora kinase inhibitors AZD1152 and VX680 on canine osteosarcoma cells. Cytotoxicity was seen in all four cell lines; however, half-maximal inhibitory concentrations were significantly higher than in human leukaemia and canine lymphoma cells. AZD1152 reduced Aurora kinase B phosphorylation, indicating resistance was not because of failure of target recognition. Efflux mediated by ABCB1 and ABCG2 transporters is one known mechanism of resistance against these drugs and verapamil enhanced AZD1152-induced apoptosis; however, these transporters were only expressed by a small percentage of cells in each line and the effects of verapamil were modest, suggesting other mechanisms contribute to resistance. Our results indicate that canine osteosarcoma cells are resistant to Aurora kinase inhibitors and suggest that these compounds are unlikely to be useful as single agents for this disease. Further investigation of these resistance mechanisms and the potential utility of Aurora kinase inhibitors in multi-agent protocols is warranted. © 2013 Blackwell Publishing Ltd.

  6. Functions of Aurora kinase C in meiosis and cancer

    Directory of Open Access Journals (Sweden)

    Suzanne M. Quartuccio

    2015-08-01

    Full Text Available The mammalian genome encodes three Aurora kinase protein family members: A, B, and C. While Aurora kinase A (AURKA and B (AURKB are found in cells throughout the body, significant protein levels of Aurora kinase C (AURKC are limited to cells that undergo meiosis (sperm and oocyte. Despite its discovery nearly 15 years ago, we know little about the function of AURKC compared to that of the other 2 Aurora kinases. This lack of understanding can be attributed to the high sequence homology between AURKB and AURKC preventing the use of standard approaches to understand non-overlapping and meiosis I (MI-specific functions of the two kinases. Recent evidence has revealed distinct functions of AURKC in meiosis and may aid in our understanding of why chromosome segregation during MI often goes awry in oocytes. Many cancers aberrantly express AURKC, but because we do not fully understand AURKC function in its normal cellular context, it is difficult to predict the biological significance of this expression on the disease. Here, we consolidate and update what is known about AURKC signaling in meiotic cells to better understand why it has oncogenic potential.

  7. Observation and Study of Proton Aurora by using Scanning Photometer

    Science.gov (United States)

    Mochizuki, T.; Ono, T.; Kadokura, A.; Sato, N.

    2009-12-01

    The proton auroras have significant differences from electron auroras in their spectral shape. They show Doppler-shifted and broadened spectra: the spectra have Doppler-shifted (~0.5 nm shorter) peak and both bluewing (~2-4 nm) and redwing (~1.5 nm) extending. Energy spectra of precipitating protons have been estimated from this shape. Recently it is found that the intensity in the extent of the blue wing reflects more effectively by the change of the mean energy of precipitating protons than the shift of peak wavelength [Lanchester et al., 2003]. Another character of the H-beta aurora is that it is diffuse form because a proton becomes hydrogen atom due to a charge-exchange reaction with atmospheric constituent and then possible to move across the magnetic field line. By using a scanning photometer, the movement of the proton auroral belt and change of a spectrum shape associated with the variation of proton source region due to storm and substorm were reported, however, not discussed in detail yet [Deehr and Lummerzheim, 2001]. The purpose of this study is to obtain the detail characteristics of H-beta aurora for understanding of source region of energetic protons in the magnetosphere. For this purpose, a new meridian-scanning photometer (SPM) was installed at Husafell station in Iceland in last summer season and Syowa Station, Antarctica. It will contribute to investigate the distribution of energetic protons and plasma waves which cause the pitch angle scattering in the magnetosphere. The meridian-scanning photometer is able to observe at five wavelengths for H-beta emission. One channel is to measure the background level. By analyzing the data obtained by the SPM, the H-beta spectrum can be estimated by fitting a model function with it. Then it is possible to obtain distribution of precipitating protons in north-south direction. It is also possible to estimate an energy spectrum of precipitating proton, simultaneously. The instrumental parameters of the SPM is

  8. v-Src causes delocalization of Mklp1, Aurora B, and INCENP from the spindle midzone during cytokinesis failure

    Energy Technology Data Exchange (ETDEWEB)

    Soeda, Shuhei [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan); Nakayama, Yuji, E-mail: nakayama@mb.kyoto-phu.ac.jp [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan); Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414 (Japan); Honda, Takuya; Aoki, Azumi; Tamura, Naoki; Abe, Kohei; Fukumoto, Yasunori [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan); Yamaguchi, Naoto, E-mail: nyama@faculty.chiba-u.jp [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan)

    2013-06-10

    Src-family tyrosine kinases are aberrantly activated in cancers, and this activation is associated with malignant tumor progression. v-Src, encoded by the v-src transforming gene of the Rous sarcoma virus, is a mutant variant of the cellular proto-oncogene c-Src. Although investigations with temperature sensitive mutants of v-Src have shown that v-Src induces many oncogenic processes, the effects on cell division are unknown. Here, we show that v-Src inhibits cellular proliferation of HCT116, HeLa S3 and NIH3T3 cells. Flow cytometry analysis indicated that inducible expression of v-Src results in an accumulation of 4N cells. Time-lapse analysis revealed that binucleation is induced through the inhibition of cytokinesis, a final step of cell division. The localization of Mklp1, which is essential for cytokinesis, to the spindle midzone is inhibited in v-Src-expressing cells. Intriguingly, Aurora B, which regulates Mklp1 localization at the midzone, is delocalized from the spindle midzone and the midbody but not from the metaphase chromosomes upon v-Src expression. Mklp2, which is responsible for the relocation of Aurora B from the metaphase chromosomes to the spindle midzone, is also lost from the spindle midzone. These results suggest that v-Src inhibits cytokinesis through the delocalization of Mklp1 and Aurora B from the spindle midzone, resulting in binucleation. -- Highlights: • v-Src inhibits cell proliferation of HCT116, HeLa S3 and NIH3T3 cells. • v-Src induces binucleation together with cytokinesis failure. • v-Src causes delocalization of Mklp1, Aurora B and INCENP from the spindle midzone.

  9. Space structure of the glow discharge with free side boundary

    International Nuclear Information System (INIS)

    Yatsenko, N.A.

    1995-01-01

    The main purpose of this work is to reveal physical reasons, which are responsible for the formation of space structure of glow type discharge with free side boundary, both in DC and in RF electric fields. By now extensive experimental material have been accumulated in discharge physics. Also many theoretical models have been proposed for describing separate parts of discharge with the cold electrodes (cathode and anode regions, positive column and transition zones - glow luminescence and Farraday's dark space of DC-discharge, electrode regions and plasma column of RF capacitive discharge). As this takes place, the majority of known works are devoted to some one part of gas discharge - positive column, electrode regions, transition zones and so on. At the same time just now we don't know anything about space structure of free, steady-state gas discharge of glow type, as a whole, especially when the pressure p much-gt 1 Torr

  10. Laser ablation/ionization studies in a glow discharge

    International Nuclear Information System (INIS)

    Hess, K.R.; Harrison, W.W.

    1985-01-01

    The pin cathode glow discharge is used in the laboratory as an atomization/ionization source for a variety of applications, including solids mass spectrometry. Coupled with a tunable dye laser, the glow discharge may also serve as an atom reservoir for resonance ionization mass spectrometry in which the laser ionizes the discharge sputtered atoms. By tightly focusing the laser onto solid samples, various ablation effects may also be investigated. The laser may be used to generate an ionized plasma which may be directly analyzed by mass spectrometry. Alternatively, the ablated neutral atoms may be used in post-ablation excitation/ionization processes, in this case the glow discharge. The results of these investigations are the basis of this paper

  11. Spectroscopic characterisation of an atmospheric pressure glow discharge

    International Nuclear Information System (INIS)

    Gomez, S.; Steen, P.G.; Morrow, T.; Graham, W.G.

    2001-01-01

    Recently there has been considerable interest in atmospheric discharges operating in a glow discharge mode i.e. with a spatial and sheath structure similar to that of low pressure glow discharges. Here spectroscopy has been used to characterise an atmospheric pressure glow discharge (APGD), operating with either dry air, argon or helium gas flowing through the inter-electrode space and with the inter-electrode gap either free or with woven polypropylene or polyester samples present. Emission spectroscopy is used to determine the rotational and vibrational temperature of the nitrogen gas, while electron temperatures are determined from the relative intensities of Ar emission lines. Ozone production is monitored by a simple absorption technique to evaluate its potential in process control

  12. Use of universal functional optimisation for TL glow curve analysis

    International Nuclear Information System (INIS)

    Pernicka, F.; Linh, H.Q.

    1996-01-01

    The effective use of any TL instrument requires an efficient software package to be able to fulfil different tasks required by research and practical applications. One of the standard features of the package used at the NPI Prague is the application of the interactive modular system Universal Functional Optimisation (UFO) for glow curve deconvolution. The whole system has been tested on standard glow curves using different models of the TL process (a single peak described by the Podgorsak approximation, first order kinetics and/or general order kinetics). Calculated values of basic TL parameters (E and s) show a good agreement with the results obtained by other authors. The main advantage of the system is in its modularity that enables flexible changes in the TL model and mathematical procedures of the glow curve analysis. (author)

  13. Extension of spatiotemporal chaos in glow discharge-semiconductor systems.

    Science.gov (United States)

    Akhmet, Marat; Rafatov, Ismail; Fen, Mehmet Onur

    2014-12-01

    Generation of chaos in response systems is discovered numerically through specially designed unidirectional coupling of two glow discharge-semiconductor systems. By utilizing the auxiliary system approach, [H. D. I. Abarbanel, N. F. Rulkov, and M. M. Sushchik, Phys. Rev. E 53, 4528-4535 (1996)] it is verified that the phenomenon is not a chaos synchronization. Simulations demonstrate various aspects of the chaos appearance in both drive and response systems. Chaotic control is through the external circuit equation and governs the electrical potential on the boundary. The expandability of the theory to collectives of glow discharge systems is discussed, and this increases the potential of applications of the results. Moreover, the research completes the previous discussion of the chaos appearance in a glow discharge-semiconductor system [D. D. Šijačić U. Ebert, and I. Rafatov, Phys. Rev. E 70, 056220 (2004).].

  14. [The glow discharge as an atomization and ionization source

    International Nuclear Information System (INIS)

    1990-01-01

    This is to summarize the research progress in this project at the University of Florida over the past 13 months. In keeping with the directions of the Federal Demonstration Project, the report will be brief, presenting an overview of the major findings. We have continued the study of the glow discharge, primarily as an ionization source for elemental analysis. Glow discharge interest continues to grow in the analytical chemistry community as evidenced by the number of special symposia at major conferences, by the new researchers entering the field, and by the introduction of new instrumentation. There is little doubt that glow discharge mass spectrometry, for example, is now a major technique in the elemental analysis of solids

  15. Simulation of nonstationary phenomena in atmospheric-pressure glow discharge

    Science.gov (United States)

    Korolev, Yu. D.; Frants, O. B.; Nekhoroshev, V. O.; Suslov, A. I.; Kas'yanov, V. S.; Shemyakin, I. A.; Bolotov, A. V.

    2016-06-01

    Nonstationary processes in atmospheric-pressure glow discharge manifest themselves in spontaneous transitions from the normal glow discharge into a spark. In the experiments, both so-called completed transitions in which a highly conductive constricted channel arises and incomplete transitions accompanied by the formation of a diffuse channel are observed. A model of the positive column of a discharge in air is elaborated that allows one to interpret specific features of the discharge both in the stationary stage and during its transition into a spark and makes it possible to calculate the characteristic oscillatory current waveforms for completed transitions into a spark and aperiodic ones for incomplete transitions. The calculated parameters of the positive column in the glow discharge mode agree well with experiment. Data on the densities of the most abundant species generated in the discharge (such as atomic oxygen, metastable nitrogen molecules, ozone, nitrogen oxides, and negative oxygen ions) are presented.

  16. Simulation of nonstationary phenomena in atmospheric-pressure glow discharge

    International Nuclear Information System (INIS)

    Korolev, Yu. D.; Frants, O. B.; Nekhoroshev, V. O.; Suslov, A. I.; Kas’yanov, V. S.; Shemyakin, I. A.; Bolotov, A. V.

    2016-01-01

    Nonstationary processes in atmospheric-pressure glow discharge manifest themselves in spontaneous transitions from the normal glow discharge into a spark. In the experiments, both so-called completed transitions in which a highly conductive constricted channel arises and incomplete transitions accompanied by the formation of a diffuse channel are observed. A model of the positive column of a discharge in air is elaborated that allows one to interpret specific features of the discharge both in the stationary stage and during its transition into a spark and makes it possible to calculate the characteristic oscillatory current waveforms for completed transitions into a spark and aperiodic ones for incomplete transitions. The calculated parameters of the positive column in the glow discharge mode agree well with experiment. Data on the densities of the most abundant species generated in the discharge (such as atomic oxygen, metastable nitrogen molecules, ozone, nitrogen oxides, and negative oxygen ions) are presented.

  17. Target surface condition during reactive glow discharge sputtering of copper

    International Nuclear Information System (INIS)

    Depla, D; Haemers, J; Gryse, R De

    2002-01-01

    During reactive glow discharge sputtering of copper in an argon/nitrogen plasma, we noticed an abrupt change of the target voltage and the deposition rate when the nitrogen concentration in the plasma exceeds a critical value. To explain this behaviour, the target surface after reactive glow discharge sputtering was examined by x-ray photoelectron spectroscopy (XPS). An experimental arrangement was constructed that allows direct transfer of the glow discharge cathode to the XPS analysis chamber without air exposure. These XPS measurements revealed that several different chemical states of nitrogen are present in the layer that forms on the target surface. The relative concentration of these different states changes when the critical nitrogen concentration in the plasma is exceeded

  18. Extension of spatiotemporal chaos in glow discharge-semiconductor systems

    International Nuclear Information System (INIS)

    Akhmet, Marat; Fen, Mehmet Onur; Rafatov, Ismail

    2014-01-01

    Generation of chaos in response systems is discovered numerically through specially designed unidirectional coupling of two glow discharge-semiconductor systems. By utilizing the auxiliary system approach, [H. D. I. Abarbanel, N. F. Rulkov, and M. M. Sushchik, Phys. Rev. E 53, 4528–4535 (1996)] it is verified that the phenomenon is not a chaos synchronization. Simulations demonstrate various aspects of the chaos appearance in both drive and response systems. Chaotic control is through the external circuit equation and governs the electrical potential on the boundary. The expandability of the theory to collectives of glow discharge systems is discussed, and this increases the potential of applications of the results. Moreover, the research completes the previous discussion of the chaos appearance in a glow discharge-semiconductor system [D. D. Šijačić U. Ebert, and I. Rafatov, Phys. Rev. E 70, 056220 (2004).

  19. On the second kinetic order thermoluminescent glow curves

    International Nuclear Information System (INIS)

    Dang Thanh Luong; Nguyen Hao Quang; Hoang Minh Giang

    1995-01-01

    The kinetic parameters of thermoluminescent material such as CaF 2 -N and CaSO 4 -Dy with the different grain sizes are investigated in detail using the least square method of fitting. It was found that the activation energy E (or trap depth) and peak temperature T m ax are changed with the elapsed time between the irradiation and read-out for the low temperature glow curve peaks. The similar TL glow curve shapes are obtained for the different CaSO 4 -Dy grain size. (author). 7 refs., 5 figs., 2 tabs

  20. Oxidation of 1020 steel in the abnormal glow discharge

    International Nuclear Information System (INIS)

    Zúñiga, J A García; Santos, A Sarmiento; Gómez, E Y Soto

    2017-01-01

    1020 steel is a material very used for surface treatment in the abnormal glow discharge. Because the composition of the gaseous atmosphere has an important influence on the results of plasma treatment, in this work the oxidation process of 1020 steel is verified on the abnormal glow discharge under different concentrations of air (20% to 100%) at temperatures of 600°C and 900°C. For each atmosphere used mass variation is measured during the process of surface oxidation, the structure and microstructure of the oxide film formed is observed and also its mechanical properties through its microhardness. (paper)

  1. Spectroscopy and probe diagnostics of dc spherical glow discharge

    International Nuclear Information System (INIS)

    Zhovtyansky, V.A.; Nazarenko, V.G.; Syrotyuk, R.P.

    2016-01-01

    Probe and spectroscopic investigations of a spherical glow discharge (GD) were done in nitrogen and argon plasma. There were obtained the distributions of electron temperature and electron density in a discharge gap as well as plasma potential distribution. These results were compared with theoretical ones and the conclusion about their convergence was done in the present study. Particular attention was paid to the anode processes role in the formation of self-organized structure in a spherical glow discharge. It was shown the necessity of taking into account the possibility of the anode potential drop forming in this discharge region

  2. Glow curve characteristics of bulb type thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Deme, S.; Feher, I.; Felszerfalvi, J.

    1993-01-01

    TL dosemeter readers are equipped usually with thermocouples connected to the heater unit. This layout can well be applied to stabilize the position of the glow curve as a function of heating-up time. Bulb type TL dosemeters do not have temperature sensors, no possibility for stabilization, which can cause an additional readout error of dose determination. For this reason, the time dependence of glow curves for bulb-type TL dosemeters was measured, and a new microprocessor controlled readout device was developed. (N.T.) 2 refs.; 2 figs

  3. Identification of clouds and aurorae in optical data images

    CERN Document Server

    Seviour, R; Honary, F

    2003-01-01

    In this paper we present an automatic image recognition technique used to identify clouds and aurorae in digital images, taken with a CCD all-sky imager. The image recognition algorithm uses image segmentation to generate a binary block object image. Object analysis is then performed on the binary block image, the results of which are used to assess whether clouds, aurorae and stars are present in the original image. The need for such an algorithm arises because the optical study of particle precipitation into the Earth's atmosphere by the Ionosphere and Radio Propagation Group at Lancaster generates vast data-sets, over 25 000 images/year, making manual classification of all the images impractical.

  4. Aurorasaurus: A citizen science platform for viewing and reporting the aurora

    Science.gov (United States)

    MacDonald, E. A.; Case, N. A.; Clayton, J. H.; Hall, M. K.; Heavner, M.; Lalone, N.; Patel, K. G.; Tapia, A.

    2015-09-01

    A new, citizen science-based, aurora observing and reporting platform has been developed with the primary aim of collecting auroral observations made by the general public to further improve the modeling of the aurora. In addition, the real-time ability of this platform facilitates the combination of citizen science observations with auroral oval models to improve auroral visibility nowcasting. Aurorasaurus provides easily understandable aurora information, basic gamification, and real-time location-based notification of verified aurora activity to engage citizen scientists. The Aurorasaurus project is one of only a handful of space weather citizen science projects and can provide useful results for the space weather and citizen science communities. Early results are promising with over 2000 registered users submitting over 1000 aurora observations and verifying over 1700 aurora sightings posted on Twitter.

  5. Aurorae. Firework in the sky. 2. upd. ed.; Polarlichter. Feuerwerk am Himmel

    Energy Technology Data Exchange (ETDEWEB)

    Pfoser, Andreas; Eklund, Tom

    2013-07-01

    Aurorae are fascinating phenomena. As aurora borealis and aurora australis occurring in the polar regions of both earth hemispheres, their incessant color and shape games put people in wonder. The meteorologist Andreas Pfoser explains the physical connections, which lead to the formation of this natural phenomenon. The link with the activity of the sun and the interaction in the earth atmosphere are explained detailedly and understandably. The fantastic recordings, presented in generous horizontal format has collected the Finnish aurora photographer Tom Eklund over a period of time of 14 years. Thereby it succeeded, to document also some events, the origin of which on our daystar were recorded by solar satellites, so that the sequence of events from the solar eruption until the aurora spectacle can be reproduced. The present 2nd edition contains new scientific findings. Additionally numerous aurora pictures were replaced by more actual photos created with modern technology.

  6. Planetary protection in the framework of the Aurora exploration program

    Science.gov (United States)

    Kminek, G.

    The Aurora Exploration Program will give ESA new responsibilities in the field of planetary protection. Until now, ESA had only limited exposure to planetary protection from its own missions. With the proposed ExoMars and MSR missions, however, ESA will enter the realm of the highest planetary protection categories. As a consequence, the Aurora Exploration Program has initiated a number of activities in the field of planetary protection. The first and most important step was to establish a Planetary Protection Working Group (PPWG) that is advising the Exploration Program Advisory Committee (EPAC) on all matters concerning planetary protection. The main task of the PPWG is to provide recommendations regarding: Planetary protection for robotic missions to Mars; Planetary protection for a potential human mission to Mars; Review/evaluate standards & procedures for planetary protection; Identify research needs in the field of planetary protection. As a result of the PPWG deliberations, a number of activities have been initiated: Evaluation of the Microbial Diversity in SC Facilities; Working paper on legal issues of planetary protection and astrobiology; Feasibility study on a Mars Sample Return Containment Facility; Research activities on sterilization procedures; Training course on planetary protection (May, 2004); Workshop on sterilization techniques (fall 2004). In parallel to the PPWG, the Aurora Exploration Program has established an Ethical Working Group (EWG). This working group will address ethical issues related to astrobiology, planetary protection, and manned interplanetary missions. The recommendations of the working groups and the results of the R&D activities form the basis for defining planetary protection specification for Aurora mission studies, and for proposing modification and new inputs to the COSPAR planetary protection policy. Close cooperation and free exchange of relevant information with the NASA planetary protection program is strongly

  7. Measurement of the electrostatic field in aurora by antarctic rocket

    International Nuclear Information System (INIS)

    Takeya, Yoshio; Minami, Shigeyuki

    1974-01-01

    The direct measurement of the electrostatic field produced by the flow of charged particles and geomagnetic field in aurora has been carried out by means of rockets or satellites. The construction of an electric field meter and its characteristics are described, which measures the vectors of electric field with antarctic rockets. New scheme is presented: three components of an electric field are directly obtained through the probes set in three directions. (Mori, K.)

  8. Aurora kinase A controls meiosis I progression in mouse oocytes

    Czech Academy of Sciences Publication Activity Database

    Šašková, Adéla; Šolc, Petr; Baran, V.; Kubelka, Michal; Schultz, R. M.; Motlík, Jan

    2008-01-01

    Roč. 7, č. 15 (2008), s. 2368-2376 ISSN 1538-4101 R&D Projects: GA ČR GA305/06/1413; GA ČR GD204/05/H023 Institutional research plan: CEZ:AV0Z50450515 Keywords : aurora-A * MTOC * CDK1 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.120, year: 2008 www.landesbioscience.com/journals/cc/article/6361

  9. Dynamics of Auroras Conjugate to the Dayside Reconnection Region.

    Science.gov (United States)

    Mende, S. B.; Frey, H. U.; Doolittle, J. H.

    2006-12-01

    During periods of northward IMF Bz, observations of the IMAGE satellite FUV instrument demonstrated the existence of an auroral footprint of the dayside lobe reconnection region. Under these conditions the dayside "reconnection spot" is a distinct feature being separated from the dayside auroral oval. In the IMAGE data, ~100 km spatial and 2 minutes temporal resolution, this feature appeared as a modest size, 200 to 500 km in diameter, diffuse spot which was present steadily while the IMF conditions lasted and the solar wind particle pressure was large enough to create a detectable signature. Based on this evidence, dayside reconnection observed with this resolution appears to be a steady state process. There have been several attempts to identify and study the "reconnection foot print aurora" with higher resolution from the ground. South Pole Station and the network of the US Automatic Geophysical Observatories (AGO-s) in Antarctica have all sky imagers that monitor the latitude region of interest (70 to 85 degrees geomagnetic) near midday during the Antarctic winter. In this paper we present sequences of auroral images that were taken during different conditions of Bz and therefore they are high spatial resolution detailed views of the auroras associated with reconnection. During negative Bz, auroras appear to be dynamic with poleward moving auroral forms that are clearly observed by ground based imagers with a ~few km spatial resolution. During positive Bz however the extremely high latitude aurora is much more stable and shows no preferential meridional motions. It should be noted that winter solstice conditions, needed for ground based observations, produce a dipole tilt in which reconnection is not expected to be symmetric and the auroral signatures might favor the opposite hemisphere.

  10. Control system for compact SR light source 'AURORA'

    International Nuclear Information System (INIS)

    Fukami, Nobutaka; Kariya, Hiroyuki; Yamada, Hironari

    1991-01-01

    The computer control system developed for 'AURORA' has a three level hierarchical architecture. The top level is Central Intelligence System (CIS), and the second one is Autonomic Control System (ACS). The bottom one is an assembly of distributed local controllers linked to the ACS level through optical fibers. This system provides fully automated operation, and a powerful machine study capability through the associated man-machine console and an interpretive operation language. (author)

  11. Performance of the Aurora KrF ICF laser system

    International Nuclear Information System (INIS)

    Jones, J.E.; Czuchlewski, S.J.; Turner, T.P.; Watt, R.G.; Thomas, S.J.; Netz, D.A.; Tallman, C.R.; Mack, J.M.; Figueira, J.F.

    1990-01-01

    Because short wavelength lasers are attractive for inertial confinement fusion (ICF), the Department of Energy is sponsoring work at Los Alamos National Laboratory in krypton-fluoride (KrF) laser technology. Aurora is a short-pulse, high-power, KrF laser system. It serves as an end-to-end technology demonstration prototype for large-scale ultraviolet laser systems for short wavelength ICF research. The system employs optical angular multiplexing and serial amplification by electron-beam-driven KrF laser amplifiers. The 1 to 5 ns pulse of the Aurora front end is split into 96 beams which are angularly and temporally multiplexed to produce a 480 ns pulse train for amplification by four KrF laser amplifiers. In the present system configuration half (48) of the amplified pulses are demultiplexed using different optical path lengths and delivered simultaneously to target. This paper discusses how the Aurora laser system has entered the initial operational phase by delivering pulse energies of greater than one kilojoule to target

  12. The Discovery of Aurora Kinase Inhibitor by Multi-Docking-Based Virtual Screening

    Directory of Open Access Journals (Sweden)

    Jun-Tae Kim

    2014-11-01

    Full Text Available We report the discovery of aurora kinase inhibitor using the fragment-based virtual screening by multi-docking strategy. Among a number of fragments collected from eMololecules, we found four fragment molecules showing potent activity (>50% at 100 μM against aurora kinase. Based on the explored fragment scaffold, we selected two compounds in our synthesized library and validated the biological activity against Aurora kinase.

  13. Velocity persistence of Brownian particles generated in a glow discharge

    International Nuclear Information System (INIS)

    Hurd, A.J.; Ho, P.

    1989-01-01

    Quasielastic light scattering from Brownian particles in the rarefied environment of a glow discharge exhibits Gaussianlike intensity correlation functions owing to the long mean free paths of the particles. The shape of the correlation function depends on the particles' average thermal velocity and friction coefficient, which can be related to aggregate mass and structure, and indicates a crossover from kinetic to hydrodynamic behavior

  14. Altruism, warm glow, and charitable giving: Three experiments

    NARCIS (Netherlands)

    Bekkers, R.H.F.P.; Ottoni-Wilhelm, M.; Verkaik, D.J.

    2015-01-01

    One of the key questions in the science of philanthropy is to what extent donations to charity are motivated by altruism – concern for public benefits, including the well-being of recipients – and warm glow – concerns for private benefits, including emotional gratification. To disentangle altruism

  15. Time dependent argon glow discharge treatment of Al-alloy

    Indian Academy of Sciences (India)

    The energy dispersive microanalysis by X-rays (EDX) is used to determine ... surface preparation of vacum components and vacuum system of any size. ... In this work, samples of aluminium alloy are treated under dc glow discharge .... (ii) For ałuninium, iron and germanium, relative weight percentage decreases or in-.

  16. Camp GLOW (Girls Leading Our World): Handbook for Volunteers.

    Science.gov (United States)

    Peace Corps, Washington, DC. Information Collection and Exchange Div.

    Camp GLOW (Girls Leading Our World) began in Romania in 1995 as a weeklong leadership camp with the purpose of encouraging young women to become active citizens by building their self-esteem and confidence, increasing their self-awareness, and developing their skills in goal-setting, assertiveness, and career and life planning. Since that first…

  17. An algorithm for unified analysis on the thermoluminescence glow curve

    International Nuclear Information System (INIS)

    Chung, K.S.; Park, C.Y.; Lee, J.I.; Kim, J.L.

    2014-01-01

    An algorithm was developed to integrally handle excitation by radiation, relaxation and luminescence by thermal or optical stimulation in thermoluminescence (TL) and optically stimulated luminescence (OSL) processes. This algorithm reflects the mutual interaction between traps through a conduction band. Electrons and holes are created by radiation in the beginning, and these electrons move to the trap through the conduction band. These holes move to the recombination center through a valence band. The ratio of the electrons allocated to each trap differs with the recombination probability and these values also relevant to the process of luminescence. Accordingly, the glow curve can be interpreted by taking the rate of electron–hole pairs created by ionizing radiation as a unique initial condition. This method differs from the conventional method of interpreting the measured glow curve with the initial electron concentration allocated to each trap at the end of irradiation. A program using the Visual Studio's C# subsystem was made to realize such a developed algorithm. To verify this algorithm it was applied to LiF:Mg,Cu,Si. The TL glow curve was deconvoluted with a model of five traps, one deep trap and one recombination center (RC). - Highlights: • TL glow curve deconvolution employing interacting model. • Simulation both irradiation and TL readout stages for various dose level. • Application in the identification TL kinetics of LiF:Mg,Cu,Si TLD

  18. New developments in glow discharge optical emission and mass spectrometry

    International Nuclear Information System (INIS)

    Hoffmann, Volker; Dorka, Roland; Wilken, Ludger; Wetzig, Klaus

    2000-01-01

    This paper describes new developments in flow discharge optical emission (GD-OES) and mass spectrometry (GD-MS) at IFW and presents corresponding new applications (analysis of microelectronic multi-layer system by radio frequency glow discharge optical emission spectrometry (RF-GD-OES) and analysis of pure iron by a new Grimm-type GD-MS source)

  19. Silicon solar cells made by ion implantation and glow discharge

    International Nuclear Information System (INIS)

    Ponpon, J.P.; Siffert, P.

    1975-01-01

    Three different methods of silicon solar cell preparation are considered and investigated: low energy implantation, glow discharge and prebombarded Schottky barriers. The properties of the contact layers realized by these processes are compared in terms of junction depth and sheet resistance. Preliminary results show the usefulness of these techniques for terrestrial solar cell realization [fr

  20. Inclined Zenith Aurora over Kyoto on 17 September 1770: Graphical Evidence of Extreme Magnetic Storm

    Science.gov (United States)

    Kataoka, Ryuho; Iwahashi, Kiyomi

    2017-10-01

    Red auroras were observed in Japan during an extreme magnetic storm that occurred on 17 September 1770. We show new evidence that the red aurora extended toward the zenith of Kyoto around midnight. The basic appearance of the historical painting of the red aurora is geometrically reproduced based on the inclination of the local magnetic field and a detailed description in a newly discovered diary. The presence of the inclined zenith aurora over Kyoto suggests that the intensity of the September 1770 magnetic storm is comparable to, or slightly larger than that of the September 1859 Carrington storm.

  1. Ancient writings reveal presence of aurora in 13th-century Canadian Arctic

    Science.gov (United States)

    Silverman, Sam

    Modern Norway, Iceland, and Greenland are subject to frequent displays of the aurora borealis. The aurora can be viewed on almost every clear night in the northern part of Iceland and southern Greenland, which lie in or near the auroral oval. Thus, it is surprising to find almost no mention of the aurora in medieval Norse chronicles or in the extensive Icelandic saga literature. Only one paragraph, in the "King's Mirror," a Norwegian writing dating to about 1250 C.E., notes the occurrence of the aurora in Greenland. The author reports this as hearsay and not from personal knowledge. For a fuller discussion of the Norse literature, see Brekke and Egeland [1983].

  2. AURORA on MEGSAT 1 a photon counting observatory for the Earth UV night-sky background and Aurora emission

    CERN Document Server

    Monfardini, A; Stalio, R; Mahne, N; Battiston, R; Menichelli, M; Mazzinghi, P

    2001-01-01

    A low-mass, low-cost photon-counting scientific payload has been developed and launched on a commercial microsatellite in order to study the near-UV night-sky background emission with a telescope nicknamed 'Notte' and the Aurora emission with 'Alba'. AURORA, this is the name of the experiment, will determine, with the 'Notte' channel, the overall night-side photon background in the 300-400 nm spectral range, together with a particular 2 sup + N sub 2 line (lambda sub c =337 nm). The 'Alba' channel, on the other hand, will study the Aurora emissions in four different spectral bands (FWHM=8.4-9.6 nm) centered on: 367 nm (continuum evaluation), 391 nm (1 sup - N sup + sub 2), 535 nm (continuum evaluation), 560 nm (OI). The instrument has been launched on the 26 September, 2000 from the Baikonur cosmodrome on a modified SS18 Dnepr-1 'Satan' rocket. The satellite orbit is nearly circular (h sub a sub p sub o sub g sub e sub e =648 km, e=0.0022), and the inclination of the orbital plane is 64.56 deg. An overview of...

  3. AURORA on MEGSAT 1: a photon counting observatory for the Earth UV night-sky background and Aurora emission

    International Nuclear Information System (INIS)

    Monfardini, A.; Trampus, P.; Stalio, R.; Mahne, N.; Battiston, R.; Menichelli, M.; Mazzinghi, P.

    2001-01-01

    A low-mass, low-cost photon-counting scientific payload has been developed and launched on a commercial microsatellite in order to study the near-UV night-sky background emission with a telescope nicknamed 'Notte' and the Aurora emission with 'Alba'. AURORA, this is the name of the experiment, will determine, with the 'Notte' channel, the overall night-side photon background in the 300-400 nm spectral range, together with a particular 2 + N 2 line (λ c =337 nm). The 'Alba' channel, on the other hand, will study the Aurora emissions in four different spectral bands (FWHM=8.4-9.6 nm) centered on: 367 nm (continuum evaluation), 391 nm (1 - N + 2 ), 535 nm (continuum evaluation), 560 nm (OI). The instrument has been launched on the 26 September, 2000 from the Baikonur cosmodrome on a modified SS18 Dnepr-1 'Satan' rocket. The satellite orbit is nearly circular (h apogee =648 km, e=0.0022), and the inclination of the orbital plane is 64.56 deg. An overview of the techniques adopted is given in this paper

  4. Aurora-A overexpression and aneuploidy predict poor outcome in serous ovarian carcinoma.

    Science.gov (United States)

    Lassus, Heini; Staff, Synnöve; Leminen, Arto; Isola, Jorma; Butzow, Ralf

    2011-01-01

    Aurora-A is a potential oncogene and therapeutic target in ovarian carcinoma. It is involved in mitotic events and overexpression leads to centrosome amplification and chromosomal instability. The objective of this study was to evaluate the clinical significance of Aurora-A and DNA ploidy in serous ovarian carcinoma. Serous ovarian carcinomas were analysed for Aurora-A protein by immunohistochemistry (n=592), Aurora-A copy number by CISH (n=169), Aurora-A mRNA by real-time PCR (n=158) and DNA ploidy by flowcytometry (n=440). Overexpression of Aurora-A was found in 27% of the tumors, cytoplasmic overexpression in 11% and nuclear in 17%. The cytoplasmic and nuclear overexpression were nearly mutually exclusive. Both cytoplasmic and nuclear overexpression were associated with shorter survival, high grade, high proliferation index and aberrant p53. Interestingly, only cytoplasmic expression was associated with aneuploidy and expression of phosphorylated Aurora-A. DNA ploidy was associated with poor patient outcome as well as aggressive clinicopathological parameters. In multivariate analysis, Aurora-A overexpression appeared as an independent prognostic factor for disease-free survival, together with grade, stage and ploidy. Aurora-A protein expression is strongly linked with poor patient outcome and aggressive disease characteristics, which makes Aurora-A a promising biomarker and a potential therapeutic target in ovarian carcinoma. Cytoplasmic and nuclear Aurora-A protein may have different functions. DNA aneuploidy is a strong predictor of poor prognosis in serous ovarian carcinoma. Copyright © 2010 Elsevier Inc. All rights reserved.

  5. [Automatic adjustment control system for DC glow discharge plasma source].

    Science.gov (United States)

    Wan, Zhen-zhen; Wang, Yong-qing; Li, Xiao-jia; Wang, Hai-zhou; Shi, Ning

    2011-03-01

    There are three important parameters in the DC glow discharge process, the discharge current, discharge voltage and argon pressure in discharge source. These parameters influence each other during glow discharge process. This paper presents an automatic control system for DC glow discharge plasma source. This system collects and controls discharge voltage automatically by adjusting discharge source pressure while the discharge current is constant in the glow discharge process. The design concept, circuit principle and control program of this automatic control system are described. The accuracy is improved by this automatic control system with the method of reducing the complex operations and manual control errors. This system enhances the control accuracy of glow discharge voltage, and reduces the time to reach discharge voltage stability. The glow discharge voltage stability test results with automatic control system are provided as well, the accuracy with automatic control system is better than 1% FS which is improved from 4% FS by manual control. Time to reach discharge voltage stability has been shortened to within 30 s by automatic control from more than 90 s by manual control. Standard samples like middle-low alloy steel and tin bronze have been tested by this automatic control system. The concentration analysis precision has been significantly improved. The RSDs of all the test result are better than 3.5%. In middle-low alloy steel standard sample, the RSD range of concentration test result of Ti, Co and Mn elements is reduced from 3.0%-4.3% by manual control to 1.7%-2.4% by automatic control, and that for S and Mo is also reduced from 5.2%-5.9% to 3.3%-3.5%. In tin bronze standard sample, the RSD range of Sn, Zn and Al elements is reduced from 2.6%-4.4% to 1.0%-2.4%, and that for Si, Ni and Fe is reduced from 6.6%-13.9% to 2.6%-3.5%. The test data is also shown in this paper.

  6. Study of short atmospheric pressure dc glow microdischarge in air

    Science.gov (United States)

    Kudryavtsev, Anatoly; Bogdanov, Eugene; Chirtsov, Alexander; Emelin, Sergey

    2011-10-01

    The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen and oxygen atoms; ozone molecule; and different nitrogen and oxygen ions with different plasmochemical reactions between them. Simulations predicted the main regions of the dc glow discharges including cathode and anode sheath and plasma of negative glow, Faraday dark space and transition region. Gas heating plays an important role in shaping the discharge profiles. The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen

  7. Aurora-A Expression Is Independently Associated with Chromosomal Instability in Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Yoshifumi Baba

    2009-05-01

    Full Text Available AURKA (the official symbol for Aurora-A, STK15, or BTAK regulates the function of centrosomes, spindles, and kinetochores for proper mitotic progression. AURKA overexpression is observed in various cancers including colon cancer, and a link between AURKA and chromosomal instability (CIN has been proposed. However, no study has comprehensively examined AURKA expression in relation to CIN or prognosis using a large number of tumors. Using 517 colorectal cancers in two prospective cohort studies, we detected AURKA overexpression (by immunohistochemistry in 98 tumors (19%. We assessed other molecular events including loss of heterozygosity (LOH in 2p, 5q, 17q, and 18q, the CpG island methylation phenotype (CIMP, and microsatellite instability (MSI. Prognostic significance of AURKA was evaluated by Cox regression and Kaplan-Meier method. In both univariate and multivariate logistic regressions, AURKA overexpression was significantly associated with CIN (defined as the presence of LOH in any of the chromosomal segments; multivariate odds ratio, 2.97; 95% confidence interval, 1.40–6.29; P = .0045. In multivariate analysis, AURKA was associated with cyclin D1 expression (P = .010 and inversely with PIK3CA mutation (P=.014, fatty acid synthase expression (P=.028, and family history of colorectal cancer (P = .050, but not with sex, age, body mass index, tumor location, stage, CIMP, MSI, KRAS, BRAF, BMI, LINE-1 hypomethylation, p53, p21, β-catenin, or cyclooxygenase 2. AURKA was not significantly associated with clinical outcome or survival. In conclusion, AURKA overexpression is independently associated with CIN in colorectal cancer, supporting a potential role of Aurora kinase-A in colorectal carcinogenesis through genomic instability (rather than epigenomic instability.

  8. Aurora B is dispensable for megakaryocyte polyploidization, but contributes to the endomitotic process.

    Science.gov (United States)

    Lordier, Larissa; Chang, Yunhua; Jalil, Abdelali; Aurade, Frédéric; Garçon, Loïc; Lécluse, Yann; Larbret, Frédéric; Kawashima, Toshiyuki; Kitamura, Toshio; Larghero, Jérôme; Debili, Najet; Vainchenker, William

    2010-09-30

    Polyploidization of megakaryocytes (MKs), the platelet precursors, occurs by endomitosis, a mitotic process that fails at late stages of cytokinesis. Expression and function of Aurora B kinase during endomitosis remain controversial. Here, we report that Aurora B is normally expressed during the human MK endomitotic process. Aurora B localized normally in the midzone or midbody during anaphase and telophase in low ploidy megakaryocytes and in up to 16N rare endomitotic MKs was observed. Aurora B was also functional during cytokinesis as attested by phosphorylation of both its activation site and MgcRacGAP, its main substrate. However, despite its activation, Aurora B did not prevent furrow regression. Inhibition of Aurora B by AZD1152-HQPA decreased cell cycle entry both in 2N to 4N and polyploid MKs and induced apoptosis mainly in 2N to 4N cells. In both MK classes, AZD1152-HQPA induced p53 activation and retinoblastoma hypophosphorylation. Resistance of polyploid MKs to apoptosis correlated to a high BclxL level. Aurora B inhibition did not impair MK polyploidization but profoundly modified the endomitotic process by inducing a mis-segregation of chromosomes and a mitotic failure in anaphase. This indicates that Aurora B is dispensable for MK polyploidization but is necessary to achieve a normal endomitotic process.

  9. Bora and Aurora-A continue to activate Plk1 in mitosis.

    Science.gov (United States)

    Bruinsma, Wytse; Macurek, Libor; Freire, Raimundo; Lindqvist, Arne; Medema, René H

    2014-02-15

    Polo-like kinase-1 (Plk1) is required for proper cell division. Activation of Plk1 requires phosphorylation on a conserved threonine in the T-loop of the kinase domain (T210). Plk1 is first phosphorylated on T210 in G2 phase by the kinase Aurora-A, in concert with its cofactor Bora. However, Bora was shown to be degraded prior to entry into mitosis, and it is currently unclear how Plk1 activity is sustained in mitosis. Here we show that the Bora-Aurora-A complex remains the major activator of Plk1 in mitosis. We show that a small amount of Aurora-A activity is sufficient to phosphorylate and activate Plk1 in mitosis. In addition, a fraction of Bora is retained in mitosis, which is essential for continued Aurora-A-dependent T210 phosphorylation of Plk1. We find that once Plk1 is activated, minimal amounts of the Bora-Aurora-A complex are sufficient to sustain Plk1 activity. Thus, the activation of Plk1 by Aurora-A may function as a bistable switch; highly sensitive to inhibition of Aurora-A in its initial activation, but refractory to fluctuations in Aurora-A activity once Plk1 is fully activated. This provides a cell with robust Plk1 activity once it has committed to mitosis.

  10. Latitudinally propagating on-off switching aurorae and associated geomagnetic pulsations

    International Nuclear Information System (INIS)

    Oguti, T.; Kokubun, S.; Hayashi, K.; Tsuruda, K.; Machida, S.; Kitamura, T.; Saka, O.; Watanabe, T.

    1981-01-01

    Poleward propagating on-off switching aurorae and equatorward propagating aurorae, otherwise similar, were observed simultaneously at Rabbit Lake and La Ronge, respectively, for about 40 min before dawn of Feb 20, 1980. Rabbit Lake is a high auroral latitude site at the northern end of the Saskatchewan chain of stations for the Pulsating Aurora Campaign, whereas La Ronge, due south of Rabbit, is almost at the southern edge of the auroral zone. The repetition periods of the on-off switching aurorae are about 6 to 13 s. The poleward propagating aurorae had well defined fronts of light which extended a few hundred kilometres or more in the east-west direction. The light fronts of the equatorward propagating aurorae, though comparable in extent, were less well defined: they were thicker and fuzzier. The poleward propagating aurorae moved with a speed of approximately 10 km/s whereas the equatorward ones did so with a slightly greater velocity. Geomagnetic field fluctuations were concurrent with the aurorae at both sites. At Rabbit Lake, northward (southward) field changes were associated with upward (downward) changes, whereas the trend is reversed at La Ronge, viz., northward (southward) changes with downward (upward) changes. These trends are consistent with a model of a periodic occurrence of two line currents, westward and eastward, the former moving poleward north of Rabbit Lake and the latter approaching La Ronge from the north

  11. Jupiter's Mid-Infrared Aurora: Solar Connection and Minor Constituents

    Science.gov (United States)

    Kostiuk, Theodore; Livengood, T.A.; Fast, K.E.; Hewagama, T.; Schmilling, F.; Sonnabend, G.; Delgado, J.

    2009-01-01

    High spectral resolution in the 12 pin region of the polar regions of Jupiter reveal unique information on auroral phenomena and upper stratospheric composition. Polar aurorae in Jupiter's atmosphere radiate; throughout the electromagnetic spectrum from X-ray through mid-infrared (mid-IR, 5 - 20 micron wavelength). Voyager IRIS data and ground-based. spectroscopic measurements of Jupiter's northern mid-IR aurora acquired since 1982, reveal a correlation between auroral brightness and solar activity that has not been observed in Jovian aurora at other wavelengths. Over nearly three solar cycles, Jupiter auroral ethane, emission brightness and solar 10.7-cm radar flux and sunspot number are positively correlated with high confidence. Ethane line emission intensity varies over tenfold between low and high scalar activity periods. Detailed measurements have been made using the GSFC HIPWAC spectrometer at the NASA IRTF since the last solar maximum, following the mid-IR emission through the declining phase toward solar minimum. An even more convincing correlation with solar activity is evident in these data. The spectra measured contain features that cannot be attributed to ethane and are most likely spectra of minor constituents whose molecular bands overlap the v9 band of ethane. Possible candidates are allene, propane, and other higher order hydrocarbons. These features appear to be enhanced in the active polar regions. Laboratory measurements at comparable spectral resolution of spectra of candidate molecules will be used to identify the constituents. Current analyses of these results will be described, including planned measurements on polar ethane line emission scheduled through the rise of the next solar maximum beginning in 2009, with a steep gradient to a maximum in 2012. This work is relevant to the Juno mission and to the development of the NASA/ESA Europa Jupiter System Mission.

  12. Double layers in the laboratory and above the aurora

    International Nuclear Information System (INIS)

    Block, L.P.

    1980-11-01

    Recent laboratory double layer experiments have simulated, much better than before, the conditions prevailing on auroral field lines at high altitudes. In particular, magnetic fields strong enough to magnetize the electrons (but not quite the ions) have been used. Particle and wave spectra have been measured. Wave-particle interaction has been shown to play a minor role in the only case that has been quantitatively analyzed. The three-dimensional potential distribution has been mapped. The particle budget requires the radial electric field to be outward in the no magnetic field case but inward with magnetic field, in agreement with what is observed above the aurora. (author)

  13. Dayside auroras in relation to the interplanetary magnetic field

    International Nuclear Information System (INIS)

    Sandholt, P.E.; Egeland, A.; Lybekk, B.; Deehr, C.S.

    1986-01-01

    Dynamics of dayside auroras, including cusp emissions, and their relation to the interplanetary magnetic field (IMF) have been investigated by optical ground-based observations from Svalbard, Norway, and IMF data from various satellites. Combined with the Svalbard program, simultaneous night-side observations from Alaska provide information on the large-scale behaviour of the auroral oval. Drift characteristics, spatial scale, time of duration and repetition frequency of auroral structures on the day-side, occuring at the time of large-scale oval expansions (IMF B z z positive and negative values

  14. Dust acoustic waves in a dc glow-discharge plasma

    International Nuclear Information System (INIS)

    Molotkov, V.I.; Nefedov, A.P.; Torchinskii, V.M.; Fortov, V.E.; Khrapak, A.G.

    1999-01-01

    The spontaneous excitation of low-frequency oscillations of the macroparticle density in ordered dust structures levitating in standing striations of a dc glow discharge is discovered. It is concluded on the basis of a simplified linear model of an ideal collisionless plasma that the observed instability is caused by the drift motion of ions relative to the dust, which leads to the excitation of dust acoustic oscillations of the plasma

  15. Glow plug ignitor tests in H2 mixtures

    International Nuclear Information System (INIS)

    Liparulo, N.J.; Olhoeft, J.E.; Paddleford, D.F.

    1981-01-01

    The AEP, TVA and DUKE Electric Power companies, in cooperation with Westinghouse Electric Corporation have defined a testing program to determine the effectiveness of a glow plug hydrogen ignition system. The ignitor's capability was demonstrated for both static and dynamic conditions. Tests were performed with both spray addition and fan induced turbulence. It ignited hydrogen for all tests performed. The results of tests did not differ significantly from similar tests data previously reported. This report presents a discussion of the test results

  16. Diode laser excited optogalvanic spectroscopy of glow discharges

    International Nuclear Information System (INIS)

    Barshick, C. M.; Shaw, R. W.; Jennings, L. W.; Post-Zwicker, A.; Young, J. P.; Ramsey, J. M.

    1997-01-01

    The development of diode-laser-excited isotopically-selective optogalvanic spectroscopy (OGS) of uranium metal, oxide and fluoride in a glow discharge (GD) is presented. The technique is useful for determining 235 U/( 235 U+ 238 U) isotope ratios in these samples. The precision and accuracy of this determination is evaluated, and a study of experimental parameters pertaining to optimization of the measurement is discussed. Application of GD-OGS to other f-transition elements is also described

  17. Diode laser excited optogalvanic spectroscopy of glow discharges

    International Nuclear Information System (INIS)

    Barshick, C.M.; Shaw, R.W.; Post-Zwicker, A., Young, J.P.; Ramsey, J.M.

    1996-01-01

    The development of diode-laser-excited isotopically-selective optogalvanic spectroscopy (OGS) of uranium metal, oxide and fluoride in a glow discharge (GD) is presented. The technique is useful for determining isotopic ratios of 235 U/( 235 U + 238 U) in the above samples. The precision and accuracy of this determination is evaluated, and a study of experimental parameters pertaining to optimization of he measurement is discussed. Application of the GD-OGS to other f-transition elements is also described

  18. Positional glow curve simulation for thermoluminescent detector (TLD) system design

    International Nuclear Information System (INIS)

    Branch, C.J.; Kearfott, K.J.

    1999-01-01

    Multi- and thin element dosimeters, variable heating rate schemes, and glow-curve analysis have been employed to improve environmental and personnel dosimetry using thermoluminescent detectors (TLDs). Detailed analysis of the effects of errors and optimization of techniques would be highly desirable. However, an understanding of the relationship between TL light production, light attenuation, and precise heating schemes is made difficult because of experimental challenges involved in measuring positional TL light production and temperature variations as a function of time. This work reports the development of a general-purpose computer code, thermoluminescent detector simulator, TLD-SIM, to simulate the heating of any TLD type using a variety of conventional and experimental heating methods including pulsed focused or unfocused lasers with Gaussian or uniform cross sections, planchet, hot gas, hot finger, optical, infrared, or electrical heating. TLD-SIM has been used to study the impact on the TL light production of varying the input parameters which include: detector composition, heat capacity, heat conductivity, physical size, and density; trapped electron density, the frequency factor of oscillation of electrons in the traps, and trap-conduction band potential energy difference; heating scheme source terms and heat transfer boundary conditions; and TL light scatter and attenuation coefficients. Temperature profiles and glow curves as a function of position time, as well as the corresponding temporally and/or spatially integrated glow values, may be plotted while varying any of the input parameters. Examples illustrating TLD system functions, including glow curve variability, will be presented. The flexible capabilities of TLD-SIM promises to enable improved TLD system design

  19. Glow discharge depth analysis of metallic elements in steels

    International Nuclear Information System (INIS)

    Berneron, R.

    The glow discharge lamp designed by Grimm gives new possibilities in the optical spectrometry. The plasma produced is a cool emissive source and its advantages are the following: low spectral background, no reabsorption, linear calibration, very stable emission, very high yield. The sputtering produced by ionic bombardment of the sample enables the depth repartition of several elements to be made in the same run [fr

  20. Spectroscopic Study of Electrical Glow Discharges in Gases

    Science.gov (United States)

    Reyes, P. G.; Evangelista, M.; Trujillo, C.; Castillo, F.; Rangel, J.

    2006-12-01

    The variation of the power of the light emitted in a Glow Discharge in Gases of low pressure (GDGLP) excited by a DC source was studied. A lack of dependency of the kind of gas used and the pressure it is located at was obtained. This is comparable to the potential drop which takes place in the discharge by inelastic collisions such as ionization, recombination, excitation, relaxation, etc.

  1. Expression of Aurora-B and FOXM1 predict poor survival in patients with nasopharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Pei-Yu; Luo, Dong-Hua; Mai, Hai-Qiang [State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou (China); Sun Yat-sen University Cancer Center, Department of Nasopharyngeal Carcinoma, Guangzhou (China); Li, Yan; Zeng, Ting-Ting; Li, Meng-Qing [State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou (China); Hou, Xue; Zhang, Li [State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou (China); Sun Yat-sen University Cancer Center, Department of Medical Oncology, Guangzhou (China)

    2015-08-15

    The purpose of this work was to investigate the relationship between Aurora-B, FOXM1, and clinical outcomes in patients with nasopharyngeal carcinoma (NPC) who were treated with a combination of induction chemotherapy and radiotherapy. The expression of Aurora-B and FOXM1 were investigated by immunohistochemistry using a tissue microarray (TMA) containing samples from 166 NPC patients who were treated with cisplatin (DDP) + fluorouracil (5-FU) induction chemotherapy and radiotherapy between 1999 and 2005. The relationship of Aurora-B, FOXM1, and survival of these NPC patients was analyzed. Informative TMA results were obtained in 91 tumor cases for Aurora-B and 93 tumor cases for FOXM1. The 8-year failure-free survival rate (FFS) for the Aurora-B-negative and Aurora-B-positive group was 65.6 and 37.3 %, respectively (p = 0.024), and the 8-year distant FFS (D-FFS) rate was 65.6 and 41.5 %, respectively (p = 0.047). The 8-year overall survival (OS) in the FOXM1-negative group was moderately higher than in the FOXM1-positive group (58.4 vs 39.1 %, p = 0.081). Cox regression analysis revealed that for FFS, Aurora-B expression was a significant prognostic factor (p = 0.025), while for D-FFS, Aurora-B expression was a marginally significant prognostic factor (p = 0.056). When FOXM1 expression was analyzed, the Cox regression analyses showed that FOXM1 expression was a marginally significant prognostic factor (p = 0.056) for OS. Correlation analysis showed that Aurora-B and FOXM1 expression had no significant correlation. Aurora-B and FOXM1 were both adverse prognostic markers for NPC patients treated with chemoradiotherapy. However, the two markers had no significant correlation. (orig.) [German] Ziel war die Untersuchung der Beziehung zwischen Aurora-B, FOXM1 und den klinischen Ergebnissen bei Patienten mit nasopharyngealem Karzinom (NPC), die mit einer Kombinationstherapie aus Induktionschemotherapie und Radiotherapie behandelt wurden. Die Expression von Aurora-B und

  2. Correspondence of vacuum ultraviolet aurora image with the inverted-V structure observed by Kyokko

    International Nuclear Information System (INIS)

    Kaneda, Eisuke; Mukai, Toshifumi; Hirao, Kunio.

    1982-01-01

    Since the Kyokko has been in an orbit with the inclination of 65.3 degree, various patterns of the inverted-V structure can be observed. Correspondence of vacuum ultraviolet aurora image with the inverted-V structure was studied. The energy-time diagrams were obtained. The inverted-V event occurrence map was made. The down-dusk asymmetry was recognized. The patterns of the inverted-V structure observed at present were not much different from previous ones. The observed aurora images showed not only the patterns of aurora, but also the state of aurora spreading in the polar region. Some of the observed results of energy characteristics and the aurora images are shown. (Kato, T.)

  3. Basal aurora kinase B activity is sufficient for histone H3 phosphorylation in prophase

    Directory of Open Access Journals (Sweden)

    Ly-Thuy-Tram Le

    2013-02-01

    Histone H3 phosphorylation is the hallmark of mitosis deposited by aurora kinase B. Benzo[e]pyridoindoles are a family of potent, broad, ATP-competitive aurora kinase inhibitors. However, benzo[e]pyridoindole C4 only inhibits histone H3 phosphorylation in prophase but not in metaphase. Under the C4 treatment, the cells enter into mitosis with dephosphorylated histone H3, assemble chromosomes normally and progress to metaphase, and then to anaphase. C4 also induces lagging chromosome in anaphase but we demonstrated that these chromosome compaction defects are not related to the absence of H3 phosphorylation in prophase. As a result of C4 action, mitosis lasts longer and the cell cycle is slowed down. We reproduced the mitotic defects with reduced concentrations of potent pan aurora kinase as well as with a specific aurora B ATP-competitive inhibitor; we therefore propose that histone H3 phosphorylation and anaphase chromosome compaction involve the basal activity of aurora kinase B. Our data suggest that aurora kinase B is progressively activated at mitosis entry and at anaphase onset. The full activation of aurora kinase B by its partners, in prometaphase, induces a shift in the catalytic domain of aurora B that modifies its affinity for ATP. These waves of activation/deactivation of aurora B correspond to different conformations of the chromosomal complex revealed by FRAP. The presence of lagging chromosomes may have deleterious consequences on the daughter cells and, unfortunately, the situation may be encountered in patients receiving treatment with aurora kinase inhibitors.

  4. X-ray scanning of overhead aurorae from rockets

    International Nuclear Information System (INIS)

    Barcus, J.R.; Goldberg, R.A.

    1981-01-01

    Two Nike Tomahawk rocket payloads were launched into energetic auroral events to investigate their structure and effects on the atmosphere. The instrument complement included X-ray scintillation detectors with energy discrimination in four ranges to measure the deposition of bremsstrahlung produced X-rays within the stratosphere and mesosphere. For this purpose, each instrument was designed for wide angle viewing; however, properties of the rocket motion have permitted coarse observation of distinct spatial X-ray structure. The detectors were mounted at a 45 0 angle with respect to the payload axis to permit scanning of the upper hemisphere, with rocket spin rates near 5 c/s during the upleg portion of each flight. Here, atmospheric shielding reduced energetic particle contamination effects to insignificant values below 65 to 75 km. Iterative computer techniques were used to reconstruct X-ray source maps at 100 km, taking atmospheric absorption effects into account. Payload 18.178 was launched on 21 September (0302 LMT) into an aurora observed to have two distinct azimuthal regions of optical brightness. Payload 18.179 (23 September, 0147 LMT) was launched into an aurora of more diffuse character. The presence of a two component spectrum is indicated for each event with the hard component originating in the more diffuse, optically faint regions. (author)

  5. Terrestrial aurora: astrophysical laboratory for anomalous abundances in stellar systems

    Directory of Open Access Journals (Sweden)

    I. Roth

    2014-02-01

    Full Text Available The unique magnetic structure of the terrestrial aurora as a conduit of information between the ionosphere and magnetosphere can be utilized as a laboratory for physical processes at similar magnetic configurations and applied to various evolutionary phases of the solar (stellar system. The most spectacular heliospheric abundance enhancement involves the 3He isotope and selective heavy elements in impulsive solar flares. In situ observations of electromagnetic waves on active aurora are extrapolated to flaring corona in an analysis of solar acceleration processes of 3He, the only element that may resonate strongly with the waves, as well as heavy ions with specific charge-to-mass ratios, which may resonate weaker via their higher gyroharmonics. These results are applied to two observed anomalous astrophysical abundances: (1 enhanced abundance of 3He and possibly 13C in the late stellar evolutionary stages of planetary nebulae; and (2 enhanced abundance of the observed fossil element 26Mg in meteorites as a decay product of radioactive 26Al isotope due to interaction with the flare-energized 3He in the early solar system.

  6. Dynamic rayed aurora and enhanced ion-acoustic radar echoes

    Directory of Open Access Journals (Sweden)

    E. M. Blixt

    2005-01-01

    Full Text Available The generation mechanism for naturally enhanced ion-acoustic echoes is still debated. One important issue is how these enhancements are related to auroral activity. All events of enhanced ion-acoustic echoes observed simultaneously with the EISCAT Svalbard Radar (ESR and with high-resolution narrow field-of-view auroral imagers have been collected and studied. Characteristic of all the events is the appearance of very dynamic rayed aurora, and some of the intrinsic features of these auroral displays are identified. Several of these identified features are directly related to the presence of low energy (10-100eV precipitating electrons in addition to the higher energy population producing most of the associated light. The low energy contribution is vital for the formation of the enhanced ion-acoustic echoes. We argue that this type of aurora is sufficient for the generation of naturally enhanced ion-acoustic echoes. In one event two imagers were used to observe the auroral rays simultaneously, one from the radar site and one 7km away. The data from these imagers shows that the auroral rays and the strong backscattering filaments (where the enhanced echoes are produced are located on the same field line, which is in contrast to earlier statements in the litterature that they should be separated.

  7. Pulsating aurora from electron scattering by chorus waves

    Science.gov (United States)

    Kasahara, S.; Miyoshi, Y.; Yokota, S.; Mitani, T.; Kasahara, Y.; Matsuda, S.; Kumamoto, A.; Matsuoka, A.; Kazama, Y.; Frey, H. U.; Angelopoulos, V.; Kurita, S.; Keika, K.; Seki, K.; Shinohara, I.

    2018-02-01

    Auroral substorms, dynamic phenomena that occur in the upper atmosphere at night, are caused by global reconfiguration of the magnetosphere, which releases stored solar wind energy. These storms are characterized by auroral brightening from dusk to midnight, followed by violent motions of distinct auroral arcs that suddenly break up, and the subsequent emergence of diffuse, pulsating auroral patches at dawn. Pulsating aurorae, which are quasiperiodic, blinking patches of light tens to hundreds of kilometres across, appear at altitudes of about 100 kilometres in the high-latitude regions of both hemispheres, and multiple patches often cover the entire sky. This auroral pulsation, with periods of several to tens of seconds, is generated by the intermittent precipitation of energetic electrons (several to tens of kiloelectronvolts) arriving from the magnetosphere and colliding with the atoms and molecules of the upper atmosphere. A possible cause of this precipitation is the interaction between magnetospheric electrons and electromagnetic waves called whistler-mode chorus waves. However, no direct observational evidence of this interaction has been obtained so far. Here we report that energetic electrons are scattered by chorus waves, resulting in their precipitation. Our observations were made in March 2017 with a magnetospheric spacecraft equipped with a high-angular-resolution electron sensor and electromagnetic field instruments. The measured quasiperiodic precipitating electron flux was sufficiently intense to generate a pulsating aurora, which was indeed simultaneously observed by a ground auroral imager.

  8. Effect of the interaction among traps on the shape of thermoluminescence glow curves

    International Nuclear Information System (INIS)

    Marcazzo, J.; Santiago, M.; Spano, F.; Lester, M.; Ortega, F.; Molina, P.; Caselli, E.

    2007-01-01

    The effect of the interaction among traps on the structure of thermoluminescence glow curves has been investigated by generating numerically simulated glow curves for a wide range of trap parameters. The results reported in this paper provide useful insights which assist in the analysis of experimental glow curves. The most important result shows that it is incorrect to assume beforehand that each peak is related to a specific trapping state. The validity of the quasiequilibrium approximation is briefly discussed

  9. Means of introducing an analyte into liquid sampling atmospheric pressure glow discharge

    Science.gov (United States)

    Marcus, R. Kenneth; Quarles, Jr., Charles Derrick; Russo, Richard E.; Koppenaal, David W.; Barinaga, Charles J.; Carado, Anthony J.

    2017-01-03

    A liquid sampling, atmospheric pressure, glow discharge (LS-APGD) device as well as systems that incorporate the device and methods for using the device and systems are described. The LS-APGD includes a hollow capillary for delivering an electrolyte solution to a glow discharge space. The device also includes a counter electrode in the form of a second hollow capillary that can deliver the analyte into the glow discharge space. A voltage across the electrolyte solution and the counter electrode creates the microplasma within the glow discharge space that interacts with the analyte to move it to a higher energy state (vaporization, excitation, and/or ionization of the analyte).

  10. Combustion aided by a glow plug in diesel engines under cold idling conditions

    OpenAIRE

    Li, Qile

    2016-01-01

    Glow plugs are widely used to promote the desired cold start and post-cold start combustion characteristics of light duty diesel engines. The importance of the glow plug becomes more apparent when the compression ratio is low. An experimental investigation of combustion initiation and development aided by the glow plug has been carried out on a single cylinder HPCR DI diesel engine with a low compression ratio of 15.5:1. High speed imaging of combustion initiated by the glow plug in a combust...

  11. Detection of negative ions in glow discharge mass spectrometry for analysis of solid specimens

    DEFF Research Database (Denmark)

    Canulescu, Stela; Molchan, Igor S.; Tauziede, C.

    2010-01-01

    A new method is presented for elemental and molecular analysis of halogen-containing samples by glow discharge time-of-flight mass spectrometry, consisting of detection of negative ions from a pulsed RF glow discharge in argon. Analyte signals are mainly extracted from the afterglow regime...... be used to study the distribution of a tantalum fluoride layer within the anodized tantala layer. Further, comparison is made with data obtained using glow-discharge optical emission spectroscopy, where elemental fluorine can only be detected using a neon plasma. The ionization mechanisms responsible...... for the formation of negative ions in glow discharge time-of-flight mass spectrometry are briefly discussed....

  12. Detection of irradiated foods by the thermoluminescence. Relationships between the temperature ranges of integrating TL glow curves and TL glow ratios

    International Nuclear Information System (INIS)

    Sekiguchi, Masayuki; Yamazaki, Masao; Goto, Michiko; Todoriki, Setsuko; Hagiwara, Shoji

    2007-01-01

    Our study demonstrated that the effects of the several temperature ranges for integrating TL glow intensity on the TL glow ratios by using spice-set purchased at a Turkish air port. The spice set had no labeling of irradiation feeds, but nine of 12 spices were judged as irradiated food in this study. Those temperature ranges were defined by evaluating the glow curves of irradiated TLD-100 chip (167-230degC), TLD-100 disc (177-238degC) and Dolomite element (145-258degC). Those are relatively stable and the difference of typical glow peak temperatures of TLD-100 disc in two institutes was less than 2%. On the other hand, those of TLD-100 tip was shift to higher temperature side at about 4degC because of declining of thermal conductance. The temperature ranges defined by TLD-100 were showed that discriminate more clearly between irradiated and nonirradiated spices compared with the full temperature range of TL measurement (70-400degC). With the exception of low glow intensity, background measurement for estimating net glow intensity was not necessary because TL glow ratio was hardly influenced whether the background measured or not. (author)

  13. The selective Aurora B kinase inhibitor AZD1152 is a potential new treatment for multiple myeloma.

    Science.gov (United States)

    Evans, Robert P; Naber, Claudia; Steffler, Tara; Checkland, Tamara; Maxwell, Christopher A; Keats, Jonathan J; Belch, Andrew R; Pilarski, Linda M; Lai, Raymond; Reiman, Tony

    2008-02-01

    Aurora kinases are potential targets for cancer therapy. Previous studies have validated Aurora kinase A as a therapeutic target in multiple myeloma (MM), and have demonstrated in vitro anti-myeloma effects of small molecule Aurora kinase inhibitors that inhibit both Aurora A and B. This study demonstrated that Aurora B kinase was strongly expressed in myeloma cell lines and primary plasma cells. The selective Aurora B inhibitor AZD1152-induced apoptotic death in myeloma cell lines at nanomolar concentrations, with a cell cycle phenotype consistent with that reported previously for Aurora B inhibition. In some cases, AZD1152 in combination with dexamethasone showed increased anti-myeloma activity compared with the use of either agent alone. AZD1152 was active against sorted CD138(+) BM plasma cells from myeloma patients but also, as expected, was toxic to CD138(-) marrow cells from the same patients. In a murine myeloma xenograft model, AZD1152-inhibited tumour growth at well-tolerated doses and induced cell death in established tumours, with associated mild, transient leucopenia. AZD1152 shows promise in these preclinical studies as a novel treatment for MM.

  14. Survivin inhibits anti-growth effect of p53 activated by aurora B

    International Nuclear Information System (INIS)

    Jung, Ji-Eun; Kim, Tae-Kyung; Lee, Joong-Seob; Oh, Se-Yeong; Kwak, Sungwook; Jin, Xun; Sohn, Jin-Young; Song, Min-Keun; Sohn, Young-Woo; Lee, Soo-Yeon; Pian, Xumin; Lee, Jang-Bo; Chung, Yong Gu; Choi, Young Ki; You, Seungkwon; Kim, Hyunggee

    2005-01-01

    Genomic instability and apoptosis evasion are hallmarks of cancer, but the molecular mechanisms governing these processes remain elusive. Here, we found that survivin, a member of the apoptosis-inhibiting gene family, and aurora B kinase, a chromosomal passenger protein, were co-overexpressed in the various glioblastoma cell lines and tumors. Notably, exogenous introduction of the aurora B in human BJ cells was shown to decrease cell growth and increase the senescence-associated β-galactosidase activity by activation of p53 tumor suppressor. However, aurora B overexpression failed to inhibit cell proliferation in BJ and U87MG cells transduced with dominant-negative p53 as well as in p53 -/- mouse astrocytes. Aurora B was shown to increase centrosome amplification in the p53 -/- astrocytes. Survivin was shown to induce anchorage-independent growth and inhibit anti-proliferation and drug-sensitive apoptosis caused by aurora B. Overexpression of both survivin and aurora B further accelerated the proliferation of BJ cells. Taken together, the present study indicates that survivin should accelerate tumorigenesis by inhibiting the anti-proliferative effect of p53 tumor suppressor that is activated by aurora B in normal and glioblastoma cells containing intact p53

  15. Targeting Aurora B to the equatorial cortex by MKlp2 is required for cytokinesis.

    Directory of Open Access Journals (Sweden)

    Mayumi Kitagawa

    Full Text Available Although Aurora B is important in cleavage furrow ingression and completion during cytokinesis, the mechanism by which kinase activity is targeted to the cleavage furrow and the molecule(s responsible for this process have remained elusive. Here, we demonstrate that an essential mitotic kinesin MKlp2 requires myosin-II for its localization to the equatorial cortex, and this event is required to recruit Aurora B to the equatorial cortex in mammalian cells. This recruitment event is also required to promote the highly focused accumulation of active RhoA at the equatorial cortex and stable ingression of the cleavage furrow in bipolar cytokinesis. Specifically, in drug-induced monopolar cytokinesis, targeting Aurora B to the cell cortex by MKlp2 is essential for cell polarization and furrow formation. Once the furrow has formed, MKlp2 further recruits Aurora B to the growing furrow. This process together with continuous Aurora B kinase activity at the growing furrow is essential for stable furrow propagation and completion. In contrast, a MKlp2 mutant defective in binding myosin-II does not recruit Aurora B to the cell cortex and does not promote furrow formation during monopolar cytokinesis. This mutant is also defective in maintaining the ingressing furrow during bipolar cytokinesis. Together, these findings reveal that targeting Aurora B to the cell cortex (or the equatorial cortex by MKlp2 is essential for the maintenance of the ingressing furrow for successful cytokinesis.

  16. A SUMOylation Motif in Aurora-A: Implications for Spindle Dynamics and Oncogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Pérez de Castro, Ignacio; Aguirre-Portolés, Cristina [Molecular Oncology Programme, Cell Division and Cancer Group, Centro Nacional de Investigaciones Oncológicas, Madrid (Spain); Martin, Benedicte [CNRS-UMR 6061, Institut de Génétique et Développement de Rennes, IFR 140 GFAS, Faculté de Médecine, Université Rennes 1, Rennes (France); Fernández-Miranda, Gonzalo [Molecular Oncology Programme, Cell Division and Cancer Group, Centro Nacional de Investigaciones Oncológicas, Madrid (Spain); Klotzbucher, Andrea; Kubbutat, Michael H. G. [ProQinase GmBH, Freiburg (Germany); Megías, Diego [Confocal Microscopy Core Unit, Centro Nacional de Investigaciones Oncológicas, Madrid (Spain); Arlot-Bonnemains, Yannick [CNRS-UMR 6061, Institut de Génétique et Développement de Rennes, IFR 140 GFAS, Faculté de Médecine, Université Rennes 1, Rennes (France); Malumbres, Marcos, E-mail: mmm@cnio.es, E-mail: iperez@cnio.es [Molecular Oncology Programme, Cell Division and Cancer Group, Centro Nacional de Investigaciones Oncológicas, Madrid (Spain)

    2011-12-14

    Aurora-A is a serine/threonine kinase that plays critical roles in centrosome maturation, spindle dynamics, and chromosome orientation and it is frequently over-expressed in human cancers. In this work, we show that Aurora-A interacts with the SUMO-conjugating enzyme UBC9 and co-localizes with SUMO1 in mitotic cells. Aurora-A can be SUMOylated in vitro and in vivo. Mutation of the highly conserved SUMOylation residue lysine 249 significantly disrupts Aurora-A SUMOylation and mitotic defects characterized by defective and multipolar spindles ensue. The Aurora-A{sup K249R} mutant has normal kinase activity but displays altered dynamics at the mitotic spindle. In addition, ectopic expression of the Aurora-A{sup K249R} mutant results in a significant increase in susceptibility to malignant transformation induced by the Ras oncogene. These data suggest that modification by SUMO residues may control Aurora-A function at the spindle and that deficiency of SUMOylation of this kinase may have important implications for tumor development.

  17. Simulations of the neutral structure within the dusk side aurora

    Directory of Open Access Journals (Sweden)

    H. F. Parish

    2006-10-01

    Full Text Available Observations of neutral winds from rocket release experiments within the premidnight and postmidnight substorm recovery phase aurora, show very large E-region neutral winds of several hundred m/s, where winds measured on the dusk side are even larger than those on the dawn side. These large winds are also associated with strong shears, and there is evidence that some of the regions below these shears may be unstable. The mechanisms which generate this strong vertical structure are not well understood. It is also not known whether the acceleration conditions in the pre and post midnight sectors of the aurora may produce significantly different neutral responses on the dawn and dusk sides. Simulations have been performed using a three-dimensional high resolution limited area thermosphere model to try to understand the neutral structure within the dawn and dusk side aurora. When simulations are performed using auroral forcing alone, for equivalent conditions within the dawn and dusk sectors, differences are found in the simulated response on each side. When measured values of auroral forcing parameters, and background winds and tides consistent with recent observations, are used as model inputs, some of the main features of the zonal and meridional wind observations are reproduced in the simulations, but the magnitude of the peak zonal wind around 140 km tends to be too small and the maximum meridional wind around 130 km is overestimated. The winds above 120 km altitude are found to be sensitive to changes in electric fields and ion densities, as was the case for the dawn side, but the effects of background winds and tides on the magnitudes of the winds above 120 km are found to be relatively small on the dusk side. The structure below 120 km appears to be related mainly to background winds and tides rather than auroral forcing, as was found in earlier studies on the dawn side, although the peak magnitudes of simulated wind variations in the 100 to

  18. Thermoluminescence glow curves of irradiated PMMA and low density polyethylene

    International Nuclear Information System (INIS)

    Matsuda, Koji; Nakase, Yoshiaki; Kumakiri, Yasuhito; Tsuji, Yoshio.

    1985-03-01

    Light emission from polymers is observed when polymers preirradiated with ionizing radiation at low temperature are heated gradually. The light emission is supposedly resulted from recombination of electrons with active centers produced in polymers or from some other processes involving charge transfer, but no definite explanation has been given at present on the thermoluminescent centers. This report describes our studies on the effects of impurities contained in polymers and pressure of ambient gases on the thermoluminescent glow curve of PMMA and low density polyethylene, which are often used for plastic film dosimeters. In the glow curve of PMMA, only one peak was observed at 110 K in an H 2 or He atmosphere at 760 Torr, but the intensity of the peak decreased with decreasing the H 2 or He gas pressure. At 10 -5 Torr H 2 or He atmosphere the peak disappered, and two sharp peaks appeared in the temperature range from 200 to 250 K. On the other hand, in the glow curve of low density polyethylene, three peaks were observed at 120 K, 180 K and 250 K in the presence of H 2 or He gas at 760 Torr. The effects of pressure of ambient gases and impurities in the polyethylene on these peaks indicate that the peak at 120 K is due to luminescent center produced on the surface or just below the surface of the matrix by collision of excited atoms or molecules of gases with polymer molecules, the peak at 120 K is originated from impurities in the matrix, and the peak at 250 0 K corresponds to luminescent center produced in polyethylene matrix. (author)

  19. Fatal defect in computerized glow curve deconvolution of thermoluminescence

    International Nuclear Information System (INIS)

    Sakurai, T.

    2001-01-01

    The method of computerized glow curve deconvolution (CGCD) is a powerful tool in the study of thermoluminescence (TL). In a system where the plural trapping levels have the probability of retrapping, the electrons trapped at one level can transfer from this level to another through retrapping via the conduction band during reading TL. However, at present, the method of CGCD has no affect on the electron transition between the trapping levels; this is a fatal defect. It is shown by computer simulation that CGCD using general-order kinetics thus cannot yield the correct trap parameters. (author)

  20. Use of glow discharge in measurement of diffusion profile

    International Nuclear Information System (INIS)

    Baudin, Guy

    1976-05-01

    The composition of a glow discharge plasma is a good image of the composition of the surface being erroded without fusion. The depth of metal eated away is a linear function of time in 10 to 60μ range, that is too say between 2 and 20 minutes after lightning of the lamp. So measuring the emission of the discharge is function of time gives the diffusion profile of elements either by measuring instantaneous signal or by integrating during short periods of time for weak concentration. Examples of application for diffusion of N 2 and C in steel will be given [fr

  1. Evaluation of the glow curves of a new glass matrix

    International Nuclear Information System (INIS)

    Oliveira, Nathália S.; Souza, Samara P.; Ferreira, Pâmela Z.; Dantas, Noelio O.; Silva, Anielle C.A.; Neves, Lucio P.; Perini, Ana P.; Carrera, Betzabel N.S.; Watanabe, Shigueo

    2017-01-01

    Thermoluminescence is a dosimetric technique with may be used to personal, clinical, environmental and high doses. In this work a new glass matrix, with nominal composition of 20Li 2 CO 3 .10Al 2 O 3 .25BaO.45B 2 O 3 (mol%), was studied by the thermoluminescence technique. The glow curves was be analyzed, after the irradiation of this glass matrix with high doses. The results showed that this new glass matrix has a temperature peak in 260°C, which is ideal for dosimetry applications. (author)

  2. Diode laser excited optogalvanic spectroscopy of glow discharges

    International Nuclear Information System (INIS)

    Barshick, C.M.; Shaw, R.W.; Jennings, L.W.; Post-Zwicker, A.; Young, J.P.; Ramsey, J.M.

    1997-01-01

    The development of diode-laser-excited isotopically-selective optogalvanic spectroscopy (OGS) of uranium metal, oxide and fluoride in a glow discharge (GD) is presented. The technique is useful for determining 235 U/( 235 U+ 238 U) isotope ratios in these samples. The precision and accuracy of this determination is evaluated, and a study of experimental parameters pertaining to optimization of the measurement is discussed. Application of GD-OGS to other f-transition elements is also described. copyright 1997 American Institute of Physics

  3. Experimental study of spatial distribution of Ar glow discharge plasma

    International Nuclear Information System (INIS)

    Guo, X.M.; Zhou, T.D.; Pai, S.T.

    1996-01-01

    The characteristics of the spatial distribution of Ar glow discharge plasma were experimentally investigated. By means of direct comparisons between theory and experiment, the effects of the variation of gap separation, gas pressure, and electrode radius on the spatial distributions of electron density and electric field were studied. Results indicate that the maximum electron density moves toward the cathode as the gap separation or gas pressure increases while variation of electrode radius produces little effect. Predictions from a theoretical model have been experimentally verified. General agreements between theory and experiment were found to be reasonably good except in the cathode region, where discrepancy exists. copyright 1996 American Institute of Physics

  4. Glow discharge lamp: a light source for optical emission spectroscopy

    International Nuclear Information System (INIS)

    Vishwanathan, K.S.; Srinivasan, V.; Nalini, S.; Mahalingam, T.R.

    1990-01-01

    A glow discharge lamp based on a modified version of the Grimm design has been fabricated. Its utility as a radiation source for optical emmission spectrography by standardising a method for the analysis of low alloy steels using a set of certified standards from DMRL, Hyderabad, has been demonstrated. A model has been proposed where the sputtering rates of different metals have been correlated with their heats of sublimation, metallic radii and densities. Sputtering rates of ten different metals obtained from literature have been used to test this model, and the correlation appears to be excellent. (author). 19 re fs., 13 figs., 2 tabs

  5. The mechanism of nickel ferrite formation by glow discharge effect

    Science.gov (United States)

    Frolova, L. A.

    2018-04-01

    The influence of various factors on the formation of nickel ferrite by the glow discharge effect has been studied. The ferritization process in the system FeSO4-NiSO4-NaOH-H2O has been studied by the methods of potentiometric titration, measurement of electrical conductivity, residual concentrations and apparent sediment volume. It has been established that the process proceeds in a multistage fashion at pH 11-12 with the formation of polyhydroxo complexes, an intermediate compound and the ferrite formation by its oxidation with active radicals.

  6. Uncertainty of relative sensitivity factors in glow discharge mass spectrometry

    Science.gov (United States)

    Meija, Juris; Methven, Brad; Sturgeon, Ralph E.

    2017-10-01

    The concept of the relative sensitivity factors required for the correction of the measured ion beam ratios in pin-cell glow discharge mass spectrometry is examined in detail. We propose a data-driven model for predicting the relative response factors, which relies on a non-linear least squares adjustment and analyte/matrix interchangeability phenomena. The model provides a self-consistent set of response factors for any analyte/matrix combination of any element that appears as either an analyte or matrix in at least one known response factor.

  7. Beam propagation considerations in the Aurora laser system

    International Nuclear Information System (INIS)

    Rosoche, L.A.; Mc Leod, J.; Hanlon, J.A.

    1987-01-01

    Aurora is a high-power KrF laser system now being constructed for inertial confinement fusion (ICF) studies. It will use optical angular multiplexing and serial amplification by electron-beam-driven KrF amplifiers to deliver a stacked, multikilojoule 5-ns-duration laser pulse to ICF targets. The requirements of angular multiplexing KrF lasers at the multikilojoule level dictate path lengths on the order of 1 km. The inherent complicated path crossings produced by angular multiplexing and pulse stacking do not allow isolation of individual beam lines, so the optical quality of the long beam paths must be controlled. Propagation of the 248-nm light beams over long paths in air is affected by scattering, absorption thermal gradients and turbulence, beam alignment, and control and optical component figure errors

  8. Environmental impact assessment for the Syncrude Aurora Mine

    International Nuclear Information System (INIS)

    1996-01-01

    Syncrude Canada has applied to the Alberta Energy and Utilities Board (AEUB) and Alberta Environmental Protection for approval to construct and operate the Aurora Mine, its new oil sands mine and associated bitumen facilities located 70 km northeast of Fort McMurray, Alberta. Volume 1, the principal volume in the set of 31 volumes, includes the detailed assessment of environmental effects on air quality, noise, surface water flows, surface water quality, groundwater flow and quality, geology, terrain and soils overburden, fisheries and aquatic resources, vegetation and resource use, wildlife population and habitat, human health and public safety. Baseline data for each of the above areas are contained in separate volumes. 400 refs., 162 tabs., 190 figs

  9. The charge spectrum of positive ions in a hydrogen aurora

    Science.gov (United States)

    Lynch, J.; Pulliam, D.; Leach, R.; Scherb, F.

    1976-01-01

    An auroral ion charge spectrometer was flown into a hydrogen aurora on a Javelin sounding rocket launched from Churchill, Manitoba. The instrument contained an electrostatic analyzer which selected particles with incident energy per unit charge up to 20 keV/charge and an 80-kV power supply which accelerated these ions onto an array of solid state detectors. Ions tentatively identified as H(+), He(+2), and O(+) were detected from 225 to 820 km in altitude. The experiment did not discriminate between H(+) and He(+), or between O(+), N(+), and C(+). Upper limits of highly charged heavy ion abundances have been set at 20% of the He(+2) and 0.15% of the H(+). It is concluded that both terrestrial and solar wind sources play significant roles in auroral ion precipitation.

  10. Exploring the Secrets of the Aurora Second Edition

    CERN Document Server

    Akasofu, Syun-Ichi

    2007-01-01

    This new edition of Exploring the Secrets of the Aurora is based on the author's own experiences as a scientist. It describes the history of progress made in auroral science and magnetospheric physics by providing examples of ideas, controversies, struggles, acceptance, and success. Although no general methodologies are mentioned, the hope is that the reader will learn about the history of progress in auroral science and examples of dealing with the many controversies. This book aims to help young scientific researchers learn how to persevere during periods of controversy and struggles for acceptance. In this second edition, by utilizing multiple examples, Akasofu is successful in demonstrating the importance and usefulness of Synthesis. "Probably the book's most valuable contribution to the history of space physics is precisely the narration of the discovery of substorms.---The book has special features.---Akasofu's coverage of the history of pre-space age solar-terrestrial relations is the most comprehensiv...

  11. Numerical analysis of thermoluminescence glow curves; Analisis numerico de las cruvas de termoluminiscencia

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Ros, J M; Delgado, A

    1989-07-01

    This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs.

  12. Assessing the Warm Glow Effect in Contingent Valuations for Public Libraries

    Science.gov (United States)

    Lee, Soon-Jae; Chung, Hye-Kyung; Jung, Eun-Joo

    2010-01-01

    This article aims to present evidence of the warm glow effect in a public library setting. More specifically, it tests whether individual respondents with different values for the warm glow component report different values for their willingness to pay (WTP). The data come from a contingent valuation survey conducted on randomly selected citizens…

  13. Glow experiment documentation of OMS/RCS pod and vertical stabilizer

    Science.gov (United States)

    1982-01-01

    Glow experiment documentation of one of the orbital maneuvering system (OMS) reaction control system (RCS) pods and a portion of the vertical stabilizer shows chemoluminescent effectresulting from atomic oxygen impacting the spacecraft and building to the point that the atomic oxygen atoms combine to form molecules of oxygen. The Image Intensifier on NIKON 35mm camera was used to record the glow.

  14. Glow experiment documentation of OMS/RCS pods and vertical stabilizer

    Science.gov (United States)

    1982-01-01

    Glow experiment documentation of orbital maneuvering system (OMS) reaction control system (RCS) pods and vertical stabilizer shows chemo-luminescent effect resulting from atomic oxygen impacting the spacecraft and building to the point that the atomic oxygen atoms combine to form molecules of oxygen. Image intensifier on NIKON 35mm camera was used to record glow on vertical tail and OMS pods.

  15. Bcl-XL represents a druggable molecular vulnerability during aurora B inhibitor-mediated polyploidization.

    Science.gov (United States)

    Shah, O Jameel; Lin, Xiaoyu; Li, Leiming; Huang, Xiaoli; Li, Junling; Anderson, Mark G; Tang, Hua; Rodriguez, Luis E; Warder, Scott E; McLoughlin, Shaun; Chen, Jun; Palma, Joann; Glaser, Keith B; Donawho, Cherrie K; Fesik, Stephen W; Shen, Yu

    2010-07-13

    Aurora kinase B inhibitors induce apoptosis secondary to polyploidization and have entered clinical trials as an emerging class of neocytotoxic chemotherapeutics. We demonstrate here that polyploidization neutralizes Mcl-1 function, rendering cancer cells exquisitely dependent on Bcl-XL/-2. This "addiction" can be exploited therapeutically by combining aurora kinase inhibitors and the orally bioavailable BH3 mimetic, ABT-263, which inhibits Bcl-XL, Bcl-2, and Bcl-w. The combination of ABT-263 with aurora B inhibitors produces a synergistic loss of viability in a range of cell lines of divergent tumor origin and exhibits more sustained tumor growth inhibition in vivo compared with aurora B inhibitor monotherapy. These data demonstrate that Bcl-XL/-2 is necessary to support viability during polyploidization in a variety of tumor models and represents a druggable molecular vulnerability with potential therapeutic utility.

  16. Optical aurora detectors: using natural optics to motivate education and outreach

    Science.gov (United States)

    Shaw, Joseph A.; Way, Jesse M.; Pust, Nathan J.; Nugent, Paul W.; Coate, Hans; Balster, Daniel

    2009-06-01

    Natural optical phenomena enjoy a level of interest sufficiently high among a wide array of people to provide ideal education and outreach opportunities. The aurora promotes particularly high interest, perhaps because of its relative rarity in the areas of the world where most people live. A project is being conducted at Montana State University to use common interest and curiosity about auroras to motivate learning and outreach through the design and deployment of optical sensor systems that detect the presence of an auroral display and send cell phone messages to alert interested people. Project participants learn about the physics and optics of the aurora, basic principles of optical system design, radiometric calculations and calibrations, electro-optical detectors, electronics, embedded computer systems, and computer software. The project is moving into a stage where it will provide greatly expanded outreach and education opportunities as optical aurora detector kits are created and disbursed to colleges around our region.

  17. Research on the Plasma Anemometer Based on AC Glow Discharge

    Directory of Open Access Journals (Sweden)

    Bing Yu

    2017-01-01

    Full Text Available A new plasma anemometer based on AC glow discharge is designed in this article. Firstly, theoretical analysis of plasma anemometer working principle is introduced to prove the feasibility of the experimental measurement method. Then the experiments are carried out to study the effects of different parameters on the static discharge characteristics of the plasma anemometer system, by which the system optimization methods are obtained. Finally, several groups of appropriate parameters are selected to build the plasma anemometer system based on resistance capacitance coupling negative feedback AC glow discharge, and different airflow speeds are applied to obtain the achievable velocity measurement range. The results show that there is a linear relationship between airflow velocity and discharge current in an allowable error range, which can be applied for airflow velocity measurement. Negative feedback coupling module, which is composed of the coupling resistance and the coupling capacitance, has good effects on improving the system stability. The measurement range of the airflow velocity is significantly increased when the electrode gap is 3 mm, coupling resistance is 470 Ω, and coupling capacitance is 220 pF.

  18. Synthesis of nanoparticles in an atmospheric pressure glow discharge

    International Nuclear Information System (INIS)

    Barankin, M.D.; Creyghton, Y.; Schmidt-Ott, A.

    2006-01-01

    Nanopowders are produced in a low temperature, non-equilibrium plasma jet (APPJ), which produces a glow discharge at atmospheric pressure, for the first time. Amorphous carbon and iron nanoparticles have been synthesized from Acetylene and Ferrocene/H 2 , respectively. High generation rates are achieved from the glow discharge at near-ambient temperature (40-80 deg. C), and rise with increasing plasma power and precursor concentration. Fairly narrow particle size distributions are measured with a differential mobility analyzer (DMA) and an aerosol electrometer (AEM), and are centered around 30-35 nm for carbon and 20-25 nm for iron. Particle characteristics analyzed by TEM and EDX reveal amorphous carbon and iron nanoparticles. The Fe particles are highly oxidized on exposure to air. Comparison of the mobility and micrograph diameters reveal that the particles are hardly agglomerated or unagglomerated. This is ascribed to the unipolar charge on particles in the plasma. The generated particle distributions are examined as a function of process parameters

  19. Shock wave interaction with pulsed glow discharge and afterglow plasmas

    International Nuclear Information System (INIS)

    Podder, N.K.; LoCascio, A.C.

    2009-01-01

    Acoustic shock waves are launched by the spark-discharge of a high voltage capacitor in pulsed glow discharge and afterglow plasmas. The glow discharge section of the shock tube is switched on for a period of less than one second at a time, during which a shock wave is launched starting with a large delay between the plasma switch-on and the shock-launch. In the subsequent runs this delay is decremented in equal time intervals up to the plasma switch-on time. A photo acoustic deflection method sensitive to the density gradient of the shock wave is used to study the propagating shock structure and velocity in the igniting plasma. A similar set of measurements are also performed at the plasma switch-off, in which the delay time is incremented in equal time intervals from the plasma switch-off time until the afterglow plasma fully neutralizes itself into the room-temperature gas. Thus, complete time histories of the shock wave propagation in the igniting plasma, as well as in the afterglow plasma, are produced. In the igniting plasma, the changes in the shock-front velocity and dispersion are found to be a strong non-linear function of delay until a saturation point is reached. On the other hand, in the afterglow plasma the trend has been opposite and reversing towards the room temperature values. The observed shock wave properties in both igniting and afterglow plasmas correlate well with the inferred temperature changes in the two plasmas

  20. Closed form analytic solutions describing glow discharge plasma

    International Nuclear Information System (INIS)

    Pai, S.T.; Guo, X.M.; Zhou, T.D.

    1996-01-01

    On the basis of an analytic model developed previously [S. T. Pai, J. Appl. Phys. 71, 5820 (1992)], an improved version of the model for the description of dc glow discharge plasma was successfully developed. A set of closed form solutions was obtained from the governing equations. The two-dimensional, analytic solutions are functional and completely satisfy the governing equations, the actual boundary conditions, and Maxwell equations. They can be readily used to carry out numerical calculations without the necessity of employing any assumed boundary conditions. Results obtained from the model reveal that as the discharge gap spacing or pressure increases the maximum value in the electron density distribution moves toward the cathode. At a sufficiently large value of gap spacing, the positive column phenomenon begins to appear in the discharge region. The model has the capability of treating the positive column and negative glow as a continuous system without the necessity of studying them separately. The model also predicts a sharp rise of the positive ion density near the cathode and field reversal in the anode region. Variation of the electrode radius produces little effect on the axial spatial distribution of physical quantities studied. copyright 1996 American Institute of Physics

  1. Electric probe data analysis for glow discharge diagnostics

    International Nuclear Information System (INIS)

    Cain, B.L.

    1987-01-01

    This report summarizes the development and application of digital computations for the analysis of data from an electric probe used for glow discharge diagnostics. The essential physics of the probe/discharge interaction is presented, along with formulations from modern electric probe theory. These results are then digitally implemented by a set of computer programs which both calculate discharge properties of electron temperature and density, and aid in the interpretation of these property estimates. The method of analysis, and the theories selected for implementation, are valid only for low pressure, collisionless sheath, and quiescent discharges where the single electric probe has a much smaller area than the discharge reference electrode. However, certain algorithms are included which, in some cases, can extend the analysis into intermediate pressure regimes. The digital programs' functional capabilities are demonstrated by the analysis of experimental probe data, collected using a laboratory glow discharge. Typical sources of error inherent in the electric probe method are discussed, along with an analysis of error induced by the computational methods of the programs. 27 refs., 49 figs., 20 tabs

  2. E region neutral winds in the postmidnight diffuse aurora during the atmospheric response in aurora 1 rocket campaign

    International Nuclear Information System (INIS)

    Brinkman, D.G.; Walterscheid, R.L.; Lyons, L.R.

    1995-01-01

    Measured E region neutral winds from the Atmospheric Response in Aurora (ARIA 1) rocket campaign are compared with winds predicted by a high-resolution nonhydrostatic dynamical thermosphere model. The ARIA 1 rockets were launched into the postmidnight diffuse aurora during the recovery phase of a substorm. Simulations have shown that electrodynamical coupling between the auroral ionosphere and the thermosphere was expected to be strong during active diffuse auroral conditions. This is the first time that simulations using the time history of detailed specifications of the magnitude and latitudinal variation of the auroral forcing based on measurements have been compared to simultaneous wind measurements. Model inputs included electron densities derived from ground-based airglow measurements, precipitating electron fluxes measured by the rocket, electron densities measured on the rocket, electric fields derived from magnetometer and satellite ion drift measurements, and large-scale background winds from a thermospheric general circulation model. Our model predicted a strong jet of eastward winds at E region heights. A comparison between model predicted and observed winds showed modest agreement. Above 135 km the model predicted zonal winds with the correct sense, the correct profile shape, and the correct altitude of the peak wind. However, it overpredicted the magnitude of the eastward winds by more than a factor or 2. For the meridional winds the model predicted the general sense of the winds but was unable to predict the structure or strength of the winds seen in the observations. Uncertainties in the magnitude and latitudinal structure of the electric field and in the magnitude of the background winds are the most likely sources of error contributing to the differences between model and observed winds. Between 110 and 135 km the agreement between the model and observations was poor because of a large unmodeled jetlike feature in the observed winds

  3. Atmospheric response in aurora experiment: Observations of E and F region neutral winds in a region of postmidnight diffuse aurora

    International Nuclear Information System (INIS)

    Larsen, M.F.; Marshall, T.R.; Mikkelsen, I.S.

    1995-01-01

    The goal of the Atmospheric Response in Aurora (ARIA) experiment carried out at Poker Flat, Alaska, on March 3, 1992, was to determine the response of the neutral atmosphere to the long-lived, large-scale forcing that is characteristic of the diffuse aurora in the postmidnight sector. A combination of chemical release rocket wind measurements, intrumented rocket composition measurements, and ground-based optical measurements were used to characterize the response of the neutral atmosphere. The rocket measurements were made at the end of a 90-min period of strong Joule heating. We focus on the neutral wind measurements made with the rocket. The forcing was determined by running the assimilated mapping of ionospheric electrodynamics (AMIE) analysis procedure developed at the National Center for Atmospheric Research. The winds expected at the latitude and longitude of the experiment were calculated using the spectral thermospheric general circulation model developed at the Danish Meteorological Institute. Comparisons of the observations and the model suggest that the neutral winds responded strongly in two height ranges. An eastward wind perturbation of ∼100 m s -1 developed between 140 and 200 km altitude with a peak near 160 km. A southwestward wind with peak magnitude of ∼150 m s -1 developed near 115 km altitude. The large amplitude winds at the lower altitude are particularly surprising. They appear to be associated with the upward propagating semidiurnal tide. However, the amplitude is much larger than predicted by any of the tidal models, and the shear found just below the peak in the winds was nomially unstable with a Richardson number of ∼0.08. 17 refs., 12 figs

  4. Aurorae between miracle and reality. History of culture and physics of a celestial phenomenon

    International Nuclear Information System (INIS)

    Schlegel, Birgit; Schlegel, Kristian

    2011-01-01

    Since the 18th century natural-researchers have searched for the natural-scientific explanations for the generation of aurorae, but just in ther 20th century the puzzle was completely solved. Facts from physics, geophysics, and space research, which are in connection with the generation of aurorae, are scientifically precisely explained in a generally understandable text up to the latest researches. Numerous pictures, photos, graphics, text extracts, as well as statements on the literature and on internet pages supplement the text.

  5. Phosphorylation of CPAP by Aurora-A Maintains Spindle Pole Integrity during Mitosis

    OpenAIRE

    En-Ju Chou; Liang-Yi Hung; Chieh-Ju C. Tang; Wen-Bin Hsu; Hsin-Yi Wu; Pao-Chi Liao; Tang K. Tang

    2016-01-01

    CPAP is required for centriole elongation during S/G2 phase, but the role of CPAP in mitosis is incompletely understood. Here, we show that CPAP maintains spindle pole integrity through its phosphorylation by Aurora-A during mitosis. Depletion of CPAP induced a prolonged delay in mitosis, pericentriolar material (PCM) dispersion, and multiple mitotic abnormalities. Further studies demonstrated that CPAP directly interacts with and is phosphorylated by Aurora-A at serine 467 during mitosis. In...

  6. The evening diffuse radio aurora, field-aligned currents and particle precipitation

    International Nuclear Information System (INIS)

    Unwin, R.S.

    1980-01-01

    The relationship of the afternoon/evening diffuse radio aurora, proton and electron precipitation and field-aligned currents is studied with data from the auroral radar at Slope Point, New Zealand, and the ISIS 2 satellite. It is shown that there is a very close association between the radio aurora and (primarily downward) field-aligned currents, which confirms and extends previous work, but that there is no clear relation with either proton or electron precipitation. (author)

  7. Historical space weather monitoring of prolonged aurora activities in Japan and in China

    Science.gov (United States)

    Kataoka, Ryuho; Isobe, Hiroaki; Hayakawa, Hisashi; Tamazawa, Harufumi; Kawamura, Akito Davis; Miyahara, Hiroko; Iwahashi, Kiyomi; Yamamoto, Kazuaki; Takei, Masako; Terashima, Tsuneyo; Suzuki, Hidehiko; Fujiwara, Yasunori; Nakamura, Takuji

    2017-02-01

    Great magnetic storms are recorded as aurora sightings in historical documents. The earliest known example of "prolonged" aurora sightings, with aurora persistent for two or more nights within a 7 day interval at low latitudes, in Japan was documented on 21-23 February 1204 in Meigetsuki, when a big sunspot was also recorded in China. We have searched for prolonged events over the 600 year interval since 620 in Japan based on the catalogue of Kanda and over the 700 year interval since 581 in China based on the catalogues of Tamazawa et al. (2017) and Hayakawa et al. (2015). Before the Meigetsuki event, a significant fraction of the 200 possible aurora sightings in Sòng dynasty (960-1279) of China was detected at least twice within a 7 day interval and sometimes recurred with approximately the solar rotation period of 27 days. The majority of prolonged aurora activity events occurred around the maximum phase of solar cycles rather than around the minimum, as estimated from the 14C analysis of tree rings. They were not reported during the Oort Minimum (1010-1050). We hypothesize that the prolonged aurora sightings are associated with great magnetic storms resulting from multiple coronal mass ejections from the same active region. The historical documents therefore provide useful information to support estimation of great magnetic storm frequency, which are often associated with power outages and other societal concerns.

  8. Aurora Kinase A Promotes AR Degradation via the E3 Ligase CHIP.

    Science.gov (United States)

    Sarkar, Sukumar; Brautigan, David L; Larner, James M

    2017-08-01

    Reducing the levels of the androgen receptor (AR) is one of the most viable approaches to combat castration-resistant prostate cancer. Previously, we observed that proteasomal-dependent degradation of AR in response to 2-methoxyestradiol (2-ME) depends primarily on the E3 ligase C-terminus of HSP70-interacting protein (STUB1/CHIP). Here, 2-ME stimulation activates CHIP by phosphorylation via Aurora kinase A (AURKA). Aurora A kinase inhibitors and RNAi knockdown of Aurora A transcript selectively blocked CHIP phosphorylation and AR degradation. Aurora A kinase is activated by 2-ME in the S-phase as well as during mitosis, and phosphorylates CHIP at S273. Prostate cancer cells expressing an S273A mutant of CHIP have attenuated AR degradation upon 2-ME treatment compared with cells expressing wild-type CHIP, supporting the idea that CHIP phosphorylation by Aurora A activates its E3 ligase activity for the AR. These results reveal a novel 2-ME→Aurora A→CHIP→AR pathway that promotes AR degradation via the proteasome that may offer novel therapeutic opportunities for prostate cancer. Mol Cancer Res; 15(8); 1063-72. ©2017 AACR . ©2017 American Association for Cancer Research.

  9. miR-137 suppresses tumor growth of malignant melanoma by targeting aurora kinase A

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Xiao; Zhang, Haiping [Department of Dermatology and Venereal Disease, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Lian, Shi [Department of Dermatology and Venereal Disease, Capital Medical University, Beijing 100069 (China); Zhu, Wei, E-mail: zhuwei_2020@163.com [Department of Dermatology and Venereal Disease, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China)

    2016-07-01

    As an oncogene, aurora kinase A (AURKA) is overexpressed in various types of human cancers. However, the expression and roles of AURKA in malignant melanoma are largely unknown. In this study, a miR-137-AURKA axis was revealed to regulate melanoma growth. We found a significant increase in levels of AURKA in melanoma. Both genetic knockdown and pharmacologic inhibition of AURKA decreased tumor cell growth in vitro and in vivo. Further found that miR-137 reduced AURKA expression through interaction with its 3′ untranslated region (3′UTR) and that miR-137 was negatively correlated with AURKA expression in melanoma specimens. Overexpression of miR-137 decreased cell proliferation and colony formation in vitro. Notably, re-expression of AURKA significantly rescued miR-137-mediated suppression of cell growth and clonality. In summary, these results reveal that miR-137 functions as a tumor suppressor by targeting AURKA, providing new insights into investigation of therapeutic strategies against malignant melanoma. -- Highlights: •First reported overexpression of AURKA in melanoma. •Targeting AURKA inhibits melanoma growth in vitro and in vivo. •Further found miR-137 suppressed cell growth by binding to AURKA 3′UTR. •Re-expression of AURKA rescued miR-137-mediated suppression. •miR-137-AURKA axis may be potential therapeutic targets of melanoma.

  10. Expression of aurora kinase A is associated with metastasis-free survival in node-negative breast cancer patients

    Directory of Open Access Journals (Sweden)

    Siggelkow Wulf

    2012-11-01

    Full Text Available Abstract Background Inhibitors targeting the cell cycle-regulated aurora kinase A (AURKA are currently being developed. Here, we examine the prognostic impact of AURKA in node-negative breast cancer patients without adjuvant systemic therapy (n = 766. Methods AURKA was analyzed using microarray-based gene-expression data from three independent cohorts of node-negative breast cancer patients. In multivariate Cox analyses, the prognostic impact of age, histological grade, tumor size, estrogen receptor (ER, and HER2 were considered. Results Patients with higher AURKA expression had a shorter metastasis-free survival (MFS in the Mainz (HR 1.93; 95% CI 1.34 – 2.78; P Conclusions AURKA is associated with worse prognosis in estrogen receptor positive breast carcinomas. Patients with the highest AURKA expression (>75% percentile have a particularly bad prognosis and may profit from therapy with AURKA inhibitors.

  11. AURORA BOREALIS: a polar-dedicated European Research Platform

    Science.gov (United States)

    Wolff-Boenisch, Bonnie; Egerton, Paul; Thiede, Joern; Roberto, Azzolini; Lembke-Jene, Lester

    2010-05-01

    Polar research and in particular the properties of northern and southern high latitude oceans are currently a subject of intense scientific debate and investigations, because they are subject to rapid and dramatic climatic variations. Polar regions react more rapidly and intensively to global change than other regions of the earth. A shrinking of the Arctic sea-ice cover, potentially leading to an opening of sea passages to the north of North America and Eurasia, on the long to a "blue" Arctic Ocean would additionally have a strong impact on transport, commerce and tourism bearing potential risk for humans and complex ecosystems in the future. In spite of their critical role processes and feedbacks, especially in winter but not exclusively, are virtually unknown: The Arctic Ocean for example, it is the only basin of the world's oceans that has essentially not been sampled by the drill ships of the Deep-Sea Drilling Project (DSDP) or the Ocean Drilling Program (ODP) and its long-term environmental history and tectonic structure is therefore poorly known. Exceptions are the ODP Leg 151 and the more recent very successful ACEX-expedition of the Integrated Ocean Drilling Program (IODP) in 2004. To help to address the most pressing questions regarding climate change and related processes, a Pan-European initiative in the field of Earth system science has been put in place: AURORA BOREALIS is the largest environmental research infrastructure on the ESFRI roadmap of the European Community. AURORA BOREALIS is a very powerful research icebreaker, which will enable year-round operations in the Arctic and the Antarctic as well as in the adjacent ocean basins. Equipped with its drilling rig, the vessel is also capable to explore the presently completely unknown Arctic deep-sea floor. Last but not least, the ship is a floating observatory and mobile monitoring platform that permits to measure on a long-term basis comprehensive time series in all research fields relevant to

  12. 2D DC Subnormal Glow Discharge in Argon

    International Nuclear Information System (INIS)

    Bouchikhi, A.; Hamid, A.

    2010-01-01

    A two-dimensional time-dependent fluid model was developed and used to describe a DC subnormal glow discharge in argon with Cartesian geometry. This configuration allows us to take into account the transverse expansion of the discharge. A hydrodynamic fluid model used in this paper is based on the moments of the Boltzmann transport equation. The resultant set of governing equations consists of continuity equations (fluxes and densities) for electrons and ions, an energy equation for electrons, and Poisson's equation. Simulation results are presented for the densities of charged particles, the electric voltage, the electric field, and the electron temperature of the discharge. The results were compared with those obtained in the literature.

  13. Gas Temperature Measurement in a Glow Discharge Plasma

    Science.gov (United States)

    Sloneker, Kenneth; Podder, Nirmol; McCurdy, William E.; Shi, Shi

    2009-10-01

    In this study a relatively inexpensive quartz protected thermocouple is used to measure the gas temperature in the positive column of a glow discharge plasma. For simplicity a K-type thermocouple is used to interpret the gas temperature from the sensor voltage at pressures from 0.5 Torr to 15 Torr and discharge currents from 5 mA to 120 mA. Gas temperature is investigated as a function of the gas pressure at fixed discharge currents and as a function of discharge current at fixed gas pressures in three different gas species (Ar, N2, and He). An infinite cylinder model is used to compute the average gas temperature of the discharge from joule heating and gas thermal conductivity. The model and measurement data agree within 1% to 10% depending on plasma parameters. Data for all three gases have a similar quasi-linear increasing error as compared to the model.

  14. In-Flight Observation of Gamma Ray Glows by ILDAS

    Science.gov (United States)

    Kochkin, Pavlo; van Deursen, A. P. J.; Marisaldi, M.; Ursi, A.; de Boer, A. I.; Bardet, M.; Allasia, C.; Boissin, J.-F.; Flourens, F.; Østgaard, N.

    2017-12-01

    An Airbus A340 aircraft flew over Northern Australia with the In-Flight Lightning Damage Assessment System (ILDAS) installed onboard. A long-duration gamma ray emission was detected. The most intense emission was observed at 12 km altitude and lasted for 20 s. Its intensity was 20 times the background counts, and it was abruptly terminated by a distant lightning flash. In this work we reconstruct the aircraft path and event timeline. The glow-terminating flash triggered a discharge from the aircraft wing that was recorded by a video camera operating onboard. Another count rate increase was observed 6 min later and lasted for 30 s. The lightning activity as reported by ground networks in this region was analyzed. The measured spectra characteristics of the emission were estimated.

  15. Modeling of Pulsed Direct-Current Glow Discharge

    International Nuclear Information System (INIS)

    Du Mu; Zheng Yaru; Fan Yujia; Zhang Nan; Liu Chengsen; Wang Dezhen

    2010-01-01

    A self-consistent model was adopted to study the time evolution of low-voltage pulsed DC glow discharge. The distributions of electric field, ion density and electron density in nitrogen were investigated in our simulation, and the temporal shape of the discharge current was also obtained. Our results show that the dynamic behaviors of the discharge depends strongly on the applied pulse voltage, and the use of higher pulse voltages results in a significantly increase of discharge current and a decrease of discharge delay time. The current-voltage characteristic calculated by adjusting secondary electron emission coefficient for different applied pulse voltage under the gas pressure of 1 Torr is found in a reasonable agreement with the experimental results.

  16. Easy to implement diagnostics of a glow dielectric barrier discharge

    International Nuclear Information System (INIS)

    Massines, F.; Segur, P.

    2001-01-01

    It is relatively easier to generate plasma at atmospheric pressure rather than low pressure. In retaliation, due to the short mean free path of different particles, the diagnostics giving microscopic characteristics are more difficult to implement. This, for example, is the case of Langmuir probe or mass spectrometry although solutions have been put forward. Likewise, the strong contribution of the excited state quenching can render optical characterization result interpretation difficult. Nevertheless, there are easy to implement basic diagnostics like optical emission spectroscopy, the ultra rapid photography or the discharge current measurement. A possible approach to get to the microscopic data consists in associating the experimental results with the results of a numerical model. This is the approach undertaken for the study of a glow dielectric barrier discharge (DBD) and is described in the following text in order to illustrate the possibilities of those easy to implement diagnostics supported by the analysis of surfaces having interacted with the plasma

  17. Probiotic Bacteria Induce a ‘Glow of Health’

    Science.gov (United States)

    Smillie, Christopher; Varian, Bernard J.; Ibrahim, Yassin M.; Lakritz, Jessica R.; Alm, Eric J.; Erdman, Susan E.

    2013-01-01

    Radiant skin and hair are universally recognized as indications of good health. However, this ‘glow of health’ display remains poorly understood. We found that feeding of probiotic bacteria to aged mice induced integumentary changes mimicking peak health and reproductive fitness characteristic of much younger animals. Eating probiotic yogurt triggered epithelial follicular anagen-phase shift with sebocytogenesis resulting in thick lustrous fur due to a bacteria-triggered interleukin-10-dependent mechanism. Aged male animals eating probiotics exhibited increased subcuticular folliculogenesis, when compared with matched controls, yielding luxuriant fur only in probiotic-fed subjects. Female animals displayed probiotic-induced hyperacidity coinciding with shinier hair, a feature that also aligns with fertility in human females. Together these data provide insights into mammalian evolution and novel strategies for integumentary health. PMID:23342023

  18. Distribution of positive ion species above a diffuse midnight aurora

    International Nuclear Information System (INIS)

    Moore, T.E.

    1978-01-01

    The origin of the hot plasma in the Earth's magnetosphere is still open to investigation. Mass composition is an indicator of source region, while the distribution functions bear the signatures of transport and energization processes. Only ions identified as H + and He ++ were detected, and the He ++ was statistically marginal. Coincident magnetic storms are likely to play a crucial role in populating the magnetosphere with energized ionospheric ions. The measured proton distribution was nearly isotropic over downcoming pitch angles at all energies and showed a depleted atmospheric source cone. The high-altitude proton energy distribution had a best fit temperature of 4.5 keV and a number density of 0.17 cm- 3 , corresponding to a peak intensity just over 10 5 cm -2 s -1 sr -1 keV -1 . Altitudinal variations are consistent with the theory of charge exchange of a time-steady incident proton population. Simultaneous electron measurements can be interpreted in terms of an incident electron distribution that is also thermal wih a similar number density but a temperature of 2.5 keV. Taken together, the ion and electron data are consistent with the model of diffuse auroras in which plasma convecting in from the magnetospheric tail precipitates due to strong pitch angle diffusion on auroral field lines linking the near Earth plasma sheet

  19. Amplified spontaneous emission measurements on the Aurora large aperture module

    International Nuclear Information System (INIS)

    Oertel, J.A.; Czuchlewski, S.J.; Leland, W.T.; Turner, T.P.

    1990-01-01

    The large aperture module (LAM) of the Aurora KrF laser can be used to address a number of issues that relate to the scaling of KrF amplifiers to larger ICF systems. Perhaps foremost among these are the possible effects of amplified spontaneous emission (ASE) on laser performance. To assess this problem a 3-D computer code has been developed to model these ASE effects. The code uses an iterative procedure to arrive at a self-consistent steady state solution to the 3-D distribution of coherent and incoherent fluxes within the amplifier. Two-pass energy extraction, wall reflectivity, and nonuniform excitation are included in the model. The authors previously reported the effects of ASE on the small signal gains measured in the 1- x 1- x 2-m 3 LAM. The code also makes quantitative predictions of the ASE that should be generated in the amplifier. This paper indicates the radiance expected for a medium of uniform gain in terms of the (g - ν)L product and the parameter g/a. The quantity (g - ν)L is the product of the net gain and the path length along the direction of observation. The present experiments compare values of ASE measured at various locations around the LAM with the code predictions. The impact of ASE on amplifier output, is also discussed

  20. Ezekiel and the Northern Lights: Biblical aurora seems plausible

    Science.gov (United States)

    Siscoe, George L.; Silverman, Samuel M.; Siebert, Keith D.

    Auroral specialists have suggested that in the Bible's Old Testament book of Ezekiel, the opening vision of a "storm cloud out of the north" depicts imagery inspired by a low-latitude auroral display [Link, 1967; Eather, 1980; Silverman, 1998]. Naturally, other interpretations have been suggested, including a true epiphany, a sandstorm, a thunderstorm, a tornado, a solar halo, a hallucination, and a UFO. Biblical scholars place the site of the Ezekiel's vision about 100 km south of Babylon near Nippur, latitude ˜32°, longitude ˜45°, and the date is within a year or two of 593 B.C., or about 2600 years ago.An auroral interpretation of the vision is subject to possible refutation due to several geophysical considerations. Can auroras be seen at Ezekiel's latitude? More important, can they reach a coronal stage of development, which is what the vision requires? Was the tilt of the dipole axis favorable? Was the general level of solar activity favorable? And finally, What effect does a larger dipole moment in Ezekiel's time have on the question? All but the last question could have been answered on the basis of geophysical data a decade ago or earlier.

  1. Aurora 7 the Mercury space flight of M. Scott Carpenter

    CERN Document Server

    Burgess, Colin

    2016-01-01

    TO A NATION enthralled by the heroic exploits of the Mercury astronauts, the launch of Lt. Cmdr. Scott Carpenter on NASA’s second orbital space flight was a renewed cause for pride, jubilation and celebration. Within hours, that excitement had given way to stunned disbelief and anxiety as shaken broadcasters began preparing the American public for the very real possibility that an American astronaut and his spacecraft may have been lost at sea. In fact, it had been a very close call. Completely out of fuel and forced to manually guide Aurora 7 through the frightening inferno of re-entry, Carpenter brought the Mercury spacecraft down to a safe splashdown in the ocean. In doing so, he controversially overshot the intended landing zone. Despite his efforts, Carpenter’s performance on the MA-7 mission was later derided by powerful figures within NASA. He would never fly into space again. Taking temporary leave of NASA, Carpenter participated in the U.S. Navy’s pioneering Sealab program. For a record 30 days...

  2. Composition dependence of glow peak temperature in KCl1-xBrx doped with divalent cations

    International Nuclear Information System (INIS)

    Perez-Salas, R; Aceves, R; RodrIguez-Mijangos, R; Riveros, H G; Duarte, C

    2004-01-01

    Thermoluminescence measurements of β-irradiated Eu 2+ - and Ca 2+ - doped KCl 1-x KBr x solid solutions excited at room temperature have been carried out to identify the effect of composition on the glow peaks. A typical glow peak has been distinguished for each composition. A linear dependence of its temperature on the composition x has been found. These results indicate that for divalent impurity-doped alkali halide solid solutions these glow peak temperatures are mostly dependent on the lattice constant of the host than on the size of the anion or impurity cation

  3. Determination of the plasma impedance of a glow discharge in carbon dioxide

    Science.gov (United States)

    Kiselev, A. S.; Smirnov, E. A.

    2017-07-01

    In this work an expression for the dynamic resistance of a glow discharge flowing in long tubes is obtained and analyzed. The expression describes the physical processes occurring in the positive column of a glow discharge. The frequency dependences of the active and reactive components as well as the dynamic resistance module for the discharge conditions corresponding to CO2-lasers have been calculated. Based on the simulation results developed a computer program in the C# programming language for modeling the dynamic resistance discharge of glow discharge lasers.

  4. The Aurora Kinase in Trypanosoma brucei plays distinctive roles in metaphase-anaphase transition and cytokinetic initiation.

    Directory of Open Access Journals (Sweden)

    Ziyin Li

    2009-09-01

    Full Text Available Aurora B kinase is an essential regulator of chromosome segregation with the action well characterized in eukaryotes. It is also implicated in cytokinesis, but the detailed mechanism remains less clear, partly due to the difficulty in separating the latter from the former function in a growing cell. A chemical genetic approach with an inhibitor of the enzyme added to a synchronized cell population at different stages of the cell cycle would probably solve this problem. In the deeply branched parasitic protozoan Trypanosoma brucei, an Aurora B homolog, TbAUK1, was found to control both chromosome segregation and cytokinetic initiation by evidence from RNAi and dominant negative mutation. To clearly separate these two functions, VX-680, an inhibitor of TbAUK1, was added to a synchronized T. brucei procyclic cell population at different cell cycle stages. The unique trans-localization pattern of the chromosomal passenger complex (CPC, consisting of TbAUK1 and two novel proteins TbCPC1 and TbCPC2, was monitored during mitosis and cytokinesis by following the migration of the proteins tagged with enhanced yellow fluorescence protein in live cells with time-lapse video microscopy. Inhibition of TbAUK1 function in S-phase, prophase or metaphase invariably arrests the cells in the metaphase, suggesting an action of TbAUK1 in promoting metaphase-anaphase transition. TbAUK1 inhibition in anaphase does not affect mitotic exit, but prevents trans-localization of the CPC from the spindle midzone to the anterior tip of the new flagellum attachment zone for cytokinetic initiation. The CPC in the midzone is dispersed back to the two segregated nuclei, while cytokinesis is inhibited. In and beyond telophase, TbAUK1 inhibition has no effect on the progression of cytokinesis or the subsequent G1, S and G2 phases until a new metaphase is attained. There are thus two clearly distinct points of TbAUK1 action in T. brucei: the metaphase-anaphase transition and

  5. Syncrude's Aurora Mine : the key to future Athabasca oil sands development

    International Nuclear Information System (INIS)

    Kershaw, D.

    1998-01-01

    Syncrude's newest mine, the Aurora mine is located 35 km northeast of Syncrude's existing Mildred Lake plant, across the Athabasca River. It has a potential to produce more than 2.5 billion barrels of bitumen. Aurora will eventually consist of two surface mines, the Aurora North and Aurora South. Mining and extraction will occur at Aurora with the resulting bitumen transported as a froth by pipeline back to the existing plant for upgrading to Syncrude Sweet Blend. A total of 120 km of pipeline will be used. Syncrude has developed a new method of sending oilsand from its Athabasca deposit to the extraction plant. The company plans to phase out the dragline, bucketwheel reclaimer, and conveyor ore mining and delivery system in favour of shovel, truck, and hydrotransport technology. The advantages of hydrotransport include significant energy savings and considerably less plant infrastructure. A hydrotransport prototype is at work at Syncrude's base mine where it is responsible for 15 per cent of the production

  6. Summary of environmental impact assessment for the Syncrude Canada Ltd. Aurora Mine

    International Nuclear Information System (INIS)

    1996-01-01

    A summary of the environmental impact assessment for the Syncrude's proposed Aurora Mine was provided. Two mining areas will be opened. Aurora Mine North, located on oil sands leases 10, 12 and 34 will open first followed by the opening of Aurora Mine South, located on Lease 31. Each mining area will contain two extraction facilities, each capable of producing 6.25 million cubic metres of bitumen per year for a total annual capacity of 25 million cubic metres. The areas of land that will be disturbed by development of the Aurora Mines will total 15,171 hectares. The preferred pipeline, roadway and utility corridor and river crossing to be used for the Mine are shown. Production of SO 2 and NO x emissions from the Aurora Mine is expected to be very low, nevertheless, the cumulative effects of emissions from the mines will be addressed in the context of emissions from the existing or proposed oil sand facilities in the area. 7 tabs., 15 figs

  7. Rebamipide inhibits gastric cancer growth by targeting survivin and Aurora-B

    International Nuclear Information System (INIS)

    Tarnawski, A.; Pai, R.; Chiou, S.-K.; Chai, J.; Chu, E.C.

    2005-01-01

    Rebamipide accelerates healing of gastric ulcers and gastritis but its actions on gastric cancer are not known. Survivin, an anti-apoptosis protein, is overexpressed in stem, progenitor, and cancer cells. In gastric cancer, increased and sustained survivin expression provides survival advantage and facilitates tumor progression and resistance to anti-cancer drugs. Aurora-B kinase is essential for chromosome alignment and mitosis progression but surprisingly its role in gastric cancer has not been explored. We examined in human gastric cancer AGS cells: (1) survivin expression, (2) localization of survivin and Aurora-B (3) cell proliferation, and (4) effects of specific survivin siRNA and/or rebamipide (free radical scavenging drug) on survivin and Aurora-B expression and cell proliferation. Survivin and Aurora-B are strongly expressed in human AGS gastric cancer cells and co-localize during mitosis. Survivin siRNA significantly reduces AGS cell viability. Rebamipide significantly downregulates in AGS cell survivin expression, its association with Aurora-B and cell proliferation. Rebamipide-induced downregulation of survivin is at the transcription level and does not involve ubiquitin-proteasome pathway

  8. Glow discharge optical emission spectroscopy for accurate and well resolved analysis of coatings and thin films

    KAUST Repository

    Wilke, Marcus; Teichert, Gerd; Gemma, Ryota; Pundt, Astrid; Kirchheim, Reiner; Romanus, Henry; Schaaf, Peter

    2011-01-01

    overview on new developments in instrument design for accurate and well resolved thin film analyses is presented. The article focuses on the analytical capabilities of glow discharge optical emission spectrometry in the analysis of metallic coatings

  9. A computerized glow curve analysis (GCA) method for WinREMS thermoluminescent dosimeter data using MATLAB

    International Nuclear Information System (INIS)

    Harvey, John A.; Rodrigues, Miesher L.; Kearfott, Kimberlee J.

    2011-01-01

    A computerized glow curve analysis (GCA) program for handling of thermoluminescence data originating from WinREMS is presented. The MATLAB program fits the glow peaks using the first-order kinetics model. Tested materials are LiF:Mg,Ti, CaF 2 :Dy, CaF 2 :Tm, CaF 2 :Mn, LiF:Mg,Cu,P, and CaSO 4 :Dy, with most having an average figure of merit (FOM) of 1.3% or less, with CaSO 4 :Dy 2.2% or less. Output is a list of fit parameters, peak areas, and graphs for each fit, evaluating each glow curve in 1.5 s or less. - Highlights: → Robust algorithm for performing thermoluminescent dosimeter glow curve analysis. → Written in MATLAB so readily implemented on variety of computers. → Usage of figure of merit demonstrated for six different materials.

  10. Urochordate ascidians possess a single isoform of Aurora kinase that localizes to the midbody via TPX2 in eggs and cleavage stage embryos.

    Directory of Open Access Journals (Sweden)

    Celine Hebras

    Full Text Available Aurora kinases are key proteins found throughout the eukaryotes that control mitotic progression. Vertebrate Aurora-A and B kinases are thought to have evolved from a single Aurora-kinase isoform closest to that found in present day urochordates. In urochordate ascidians Aurora binds both TPX2 (a vertebrate AURKA partner and INCENP (a vertebrate AURKB partner and localizes to centrosomes and spindle microtubules as well as chromosomes and midbody during both meiosis and mitosis. Ascidian Aurora also displays this localization pattern during mitosis in echinoderms, strengthening the idea that non-vertebrate deuterostomes such as the urochordates and echinoderms possess a single form of Aurora kinase that has properties of vertebrate Aurora-kinase A and B. In the ascidian, TPX2 localizes to the centrosome and the spindle poles also as in vertebrates. However, we were surprised to find that TPX2 also localized strongly to the midbody in ascidian eggs and embryos. We thus examined more closely Aurora localization to the midbody by creating two separate point mutations of ascidian Aurora predicted to perturb binding to TPX2. Both forms of mutated Aurora behaved as predicted: neither localized to spindle poles where TPX2 is enriched. Interestingly, neither form of mutated Aurora localized to the midbody where TPX2 is also enriched, suggesting that ascidian Aurora midbody localization required TPX2 binding in ascidians. Functional analysis revealed that inhibition of Aurora kinase with a pharmacological inhibitor or with a dominant negative kinase dead form of Aurora caused cytokinesis failure and perturbed midbody formation during polar body extrusion. Our data support the view that vertebrate Aurora-A and B kinases evolved from a single non-vertebrate deuterostome ancestor. Moreover, since TPX2 localizes to the midbody in ascidian eggs and cleavage stage embryos it may be worthwhile re-assessing whether Aurora A kinase or TPX2 localize to the midbody

  11. A Study of Electron Decay in Nitrogen Time After-glow

    International Nuclear Information System (INIS)

    Veis, P.; Coitout, H.; Magne, L.; Cernogora, G.

    1999-01-01

    This paper deals with electron density measurements in nitrogen time after-glow using hyper frequency resonant cavity. The studied pressures are from the range 9-530 Pa and discharge currents from 20 mA up to 500 mA. Electrons decreases up to the time of 1,4 ms in after-glow depending on pressure, pulse current and pulse duration (Authors)

  12. Study on out-gassing by baking and glow discharge during wall conditioning of vacuum chamber

    International Nuclear Information System (INIS)

    Wang Zhiwen; Wei Weixing; Zhao Yuanqing; He Yanhe; Liao Yikui

    2007-01-01

    The model of out-gassing by baking and glow discharge cleaning (GDC) is set up. The properties of them are studied. Out-gassing by baking is from bulk and it obeys the diffusion equation. Out-gassing of glow discharge cleaning is mainly on surface, it is inducement out-gassing by sputtering. Thus the properties of out-gassing for baking and GDC on the HL-1M tokamak are analyzed. Some empirical formulas are given. (authors)

  13. Fuel hydrogen retention of tungsten and the reduction by inert gas glow discharges

    Energy Technology Data Exchange (ETDEWEB)

    Hino, T., E-mail: tomhino@qe.eng.hokudai.ac.jp [Laboratory of Plasma Physics and Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Yamauchi, Y.; Kimura, Y. [Laboratory of Plasma Physics and Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Nishimura, K. [National Institute for Fusion Science, Toki-shi, Gifu-ken 509-5292 (Japan); Ueda, Y. [Graduate School of Engineering, Osaka University, Suita-shi 565-0872 (Japan)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer The performances of inert gas glow discharges for reduction of fuel hydrogen retention in tungsten were systematically investigated. Black-Right-Pointing-Pointer For the tungsten with rough surface structure, the reduction of fuel hydrogen retention by inert gas discharges is quite small. Black-Right-Pointing-Pointer The deuterium glow discharge is quite useful to reduce the tritium retention in plasma facing walls in fusion reactor. Black-Right-Pointing-Pointer The wall baking with temperature higher than 700-800 K is also useful to reduce the tritium retention in plasma facing walls. - Abstract: Polycrystalline tungsten was exposed to deuterium glow discharge followed by He, Ne or Ar glow discharge. The amount of retained deuterium in the tungsten was measured using residual gas analysis. The amount of desorbed deuterium during the inert gas glow discharge was also measured. The amount of retained deuterium was 2-3 times larger compared with a case of stainless steel. The ratios of desorbed amount of deuterium by He, Ne and Ar glow discharges were 4.6, 3.1 and 2.9%, respectively. These values were one order of magnitude smaller compared with the case of stainless steel. The inert gas glow discharge is not suitable to reduce the fuel hydrogen retention for tungsten walls. However, the wall baking with a temperature higher than 700 K is suitable to reduce the fuel hydrogen retention. It is also shown that the use of deuterium glow discharge is effective to reduce the in-vessel tritium inventory in fusion reactors through the hydrogen isotope exchange.

  14. Analytical investigations of thermoluminescence glow curve on quartz for luminescence dating

    International Nuclear Information System (INIS)

    Kim, K.B.; Hong, D.G.

    2015-01-01

    Investigations of bleaching and thermoluminescence (TL) response to radiation dose of quartz are importance in luminescence dating. Although such research has been extensively carried out for various types of quartz, most work was performed on the basis of TL intensity integrated for a particular temperature range on the glow curve, without any peak separation. In this study we investigated bleaching by a blue light stimulation and radiation dose behaviour for separated TL glow peaks of quartz, which are thermally stable, by using the computerized glow curve deconvolution (CGCD) method combined with the T_m–T_s_t_o_p method. The T_m–T_s_t_o_p method indicates that the glow curve of quartz is the superposition of at least seven components (P1–P7) in the temperature range between room temperature and 450 °C. A bleaching experiment for four thermally stable glow peaks (P4–P7) using a blue light stimulation revealed that the bleaching rate of peak P4 exhibits three different exponential decays, whereas the peaks P5, P6 and P7 are bleached with two different exponential decays. After bleaching of 12 h, the TL intensity of peaks P4, P5, P6 and P7 were reduced to approximately 6%, 16%, 26% and 68% of the initial value, respectively. Additionally, in a study of the radiation dose response of the four thermally stable glow peaks, all peaks have a similar pattern, which are well fitted by a single saturating exponential function. - Highlights: • We studied the physical characteristics of the separated TL glow peaks on quartz. • The kinetic parameters of each separated glow peak are evaluated by a CGCD method. • The separated peaks were bleached with two or three exponential decays. • The dose responses for the separated peaks showed a similar growth curve.

  15. Project Aether Aurora: STEM outreach near the arctic circle

    Science.gov (United States)

    Longmier, B. W.; Bering, E. A.

    2012-12-01

    Project Aether is a program designed to immerse high-school through graduate students to field research in some of the fields of STEM. The program leaders launch high altitude weather balloons in collaboration with schools and students to teach physics concepts, experimental research skills, and to make space exploration accessible to students. A weather balloon lifts a specially designed payload package that is composed of HD cameras, GPS tracking devices, and other science equipment. The payload is constructed and attached to the balloon by the students with low-cost materials. The balloon and payload are launched with FAA clearance from a site chosen based on wind patterns and predicted landing locations. The balloon ascends over 2 hours to a maximum altitude of 100,000 feet where it bursts and allows the payload to slowly descend using a built-in parachute. The balloon's location is monitored during its flight by GPS-satellite relay. Most of the science and video data are recorded on SD cards using an Arduino digitizer. The payload is located using the GPS device. The science data are recovered from the payload and shared with the students. In April 2012, Project Aether leaders conducted a field campaign near Fairbanks Alaska, sending several student-built experiments to an altitude of 30km, underneath several strong auroral displays. Auroral physics experiments that can be done on ultra small balloons (5 cubic meters) include electric field and magnetic fluctuation observations, full spectrum and narrow band optical imaging, GPS monitoring of the total electron content of the ionosphere, x-ray detection and infrared and UV spectroscopy. The actual undergraduate student experiments will be reviewed and some data presented.; Balloon deployment underneath aurora, Fairbanks Alaska, 2012.

  16. Aurora Flight Sciences' Perseus B Remotely Piloted Aircraft in Flight

    Science.gov (United States)

    1998-01-01

    A long, slender wing and a pusher propeller at the rear characterize the Perseus B remotely piloted research aircraft, seen here during a test flight in June 1998. Perseus B is a remotely piloted aircraft developed as a design-performance testbed under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project. Perseus is one of several flight vehicles involved in the ERAST project. A piston engine, propeller-powered aircraft, Perseus was designed and built by Aurora Flight Sciences Corporation, Manassas, Virginia. The objectives of Perseus B's ERAST flight tests have been to reach and maintain horizontal flight above altitudes of 60,000 feet and demonstrate the capability to fly missions lasting from 8 to 24 hours, depending on payload and altitude requirements. The Perseus B aircraft established an unofficial altitude record for a single-engine, propeller-driven, remotely piloted aircraft on June 27, 1998. It reached an altitude of 60,280 feet. In 1999, several modifications were made to the Perseus aircraft including engine, avionics, and flight-control-system improvements. These improvements were evaluated in a series of operational readiness and test missions at the Dryden Flight Research Center, Edwards, California. Perseus is a high-wing monoplane with a conventional tail design. Its narrow, straight, high-aspect-ratio wing is mounted atop the fuselage. The aircraft is pusher-designed with the propeller mounted in the rear. This design allows for interchangeable scientific-instrument payloads to be placed in the forward fuselage. The design also allows for unobstructed airflow to the sensors and other devices mounted in the payload compartment. The Perseus B that underwent test and development in 1999 was the third generation of the Perseus design, which began with the Perseus Proof-Of-Concept aircraft. Perseus was initially developed as part of NASA's Small High-Altitude Science Aircraft (SHASA) program, which later evolved into the ERAST

  17. TL glow curve analysis of UV, beta and gamma induced limestone collected from Amarnath holy cave

    Directory of Open Access Journals (Sweden)

    Vikas Dubey

    2015-01-01

    Full Text Available The paper reports themoluminescence glow curve analysis of UV (ultraviolet, β (beta and γ (gamma induced limestone collected from Amarnath holy cave. The collected natural sample was characterized by X-ray diffraction (XRD technique and crystallite size calculated by Scherer's formula. Surface morphology and particle size was calculated by transmission electron microscopy (TEM study. Effect of annealing temperature on collected lime stone examined by TL glow curve study. The limestone was irradiated by UV radiation (254 nm source and the TL glow curve recorded for different UV exposure time. For beta irradiation Sr90 source was used and is shows intense peak at 256 °C with a shoulder peak at higher temperature range. For gamma radiation Co60 source and TL glow curve recorded for different doses of gamma. The kinetic parameters calculation was performed for different glow curve by computerized glow curve deconvolution (CGCD technique. The chemical composition of natural limestone was analyzed by energy dispersive X-ray spectroscopy (EDXS.

  18. Morphology and dynamics of aurora at fine scale: first results from the ASK instrument

    Directory of Open Access Journals (Sweden)

    H. Dahlgren

    2008-05-01

    Full Text Available The ASK instrument (Auroral Structure and Kinetics is a narrow field auroral imager, providing simultaneous images of aurora in three different spectral bands at multiple frames per second resolution. The three emission species studied are O2+ (5620 Å, O+ (7319 Å and O (7774 Å. ASK was installed and operated for the first time in an observational campaign on Svalbard, from December 2005 to March 2006. The measurements were supported by data from the Spectrographic Imaging Facility (SIF. The relation between the morphology and dynamics of the visible aurora and its spectral characteristics is studied for selected events from this period. In these events it is found that dynamic aurora is coupled to high energy electron precipitation. By studying the O2+/O intensity ratio we find that some auroral filaments are caused by higher energy precipitation within regions of lower energy precipitation, whereas other filaments are the result of a higher particle flux compared to the surroundings.

  19. Is this an arc or a glow discharge?

    International Nuclear Information System (INIS)

    Puchkarev, V.F.; Bochkarev, M.B.

    1994-01-01

    A well known criterion for distinguishing an arc discharge from a glow discharge is a low voltage drop (10--30 V) and a high current density that varies from a few tens to 10 6 A/cm 2 depending on arc type. The high current density is an attribute of arcs with cathode spots. The authors report here a study of the mechanism of emission in cathode spot arc where they realized a spotless discharge with a low voltage drop (30--50 V) and a high mean current density (10 4 --10 6 A/cm 2 ). The discharge was initiated between a broad cathode and point anode. The cathode was a smooth tungsten sphere electrode of about 100 μm in diameter. The point anode was made of various materials (Mo, Cu, Cd) with initial radius 1 μm. Before the experiment the cathode was cleaned by heating at 2,000 K at high vacuum (10 -8 Torr). The discharge was initiated by self-breakdown when electrodes under the voltage 200--500 V were brought to close proximity with each other. The cathode-anode spacing d at the moment of breakdown was estimated to be < 1 μm. The discharge current was varied within 1--3 A by changing the applied voltage and impedance of coaxial cable generator. The discharge burned during 100--1,000 ns. After the single discharge the cathode and anode were examined with a scanning electron microscope. The cathode surface exposed to the discharge was smooth, i.e. no erosion pits similar to arc craters were found on the cathode surface. The anode was shortened after discharge by 5--50 μm depending on current, material and cone angle. A high current density and low voltage drop implies that this is an arc discharge, while the cold cathode and the absence f cathode spot trace are pertinent to a dense glow discharge. The mechanism of emission involving secondary electron emission is to be discussed

  20. BOOK REVIEW: Electron acceleration in the aurora and beyond

    Science.gov (United States)

    McClements, K. G.

    1999-08-01

    Duncan Bryant is a retired space plasma physicist who spent most of his career at the Rutherford-Appleton Laboratory in Oxfordshire, England. For many years he has been challenging a widely accepted theory, that auroral electrons are accelerated by double layers, on the grounds that it contains a fundamental error (allegedly, an implicit assumption that charged particles can gain energy from conservative fields). It is, of course, right that models of particle acceleration in natural plasmas should be scrutinized carefully in terms of their consistency with basic physical principles, and I believe that Dr Bryant has performed a valuable service by highlighting this issue. He maintains that auroral electron acceleration by double layers is fundamentally untenable, and that acceleration takes place instead via resonant interactions with lower hybrid waves. In successive chapters, he asserts that essentially the same process can account for electron acceleration observed at the Earth's bow shock, in the neighbourhood of an `artificial comet' produced as part of the Active Magnetospheric Particle Explorers (AMPTE) space mission in 1984/85, in the solar wind, at the Earth's magnetopause, and in the Earth's magneto- sphere. The evidence for this is not always convincing: waves with frequencies of the order of the lower hybrid resonance are often observed in these plasma environments, but in general it is difficult to identify clearly which wave mode is being observed (whistlers, for example, have frequencies in approximately the same range as lower hybrid waves). Moreover, it is not at all clear that the waves which are observed, even if they were of the appropriate type, would have sufficient intensity to accelerate electrons to the extent observed. The author makes a persuasive case, however, that acceleration in the aurora, and in other plasma environments accessible to in situ measurements, involves some form of wave turbulence. In Chapter 2 it is pointed out that

  1. Aurora kinase A as a possible marker for endocrine resistance in early estrogen receptor positive breast cancer

    DEFF Research Database (Denmark)

    Lykkesfeldt, Anne E; Iversen, Benedikte R; Jensen, Maj-Britt

    2018-01-01

    in 980 tumors and semi quantitively scored into three groups; negative/weak, moderate and high. The Aurora A expression levels were compared to other clinico-pathological parameters and outcome, defined as disease-free survival (DFS) and overall survival (OS). RESULTS: High expression of Aurora......BACKGROUND: Cell culture studies have disclosed that the mitotic Aurora kinase A is causally involved in both tamoxifen and aromatase inhibitor resistant cell growth and thus may be a potential new marker for endocrine resistance in the clinical setting. MATERIAL AND METHODS: Archival tumor tissue...... A was found in 26.9% of patients and moderate in 57.0%. High expression was significantly associated with high malignancy grade and HER2 amplification. High Aurora A expression was significantly more frequent in ductal compared to lobular carcinomas. We found no significant association between Aurora...

  2. Energies of precipitating electrons during pulsating aurora events derived from ionosonde observations

    International Nuclear Information System (INIS)

    MacDougall, J.W.; Hofstee, J.; Koehler, J.A.

    1981-01-01

    The time-history of particle energies and fluxes associated with pulsating auroras in the morning sector is derived from ionosonde measurements. All the pulsating auroras studied showed a similar history with the pulsations occurring during a time interval of the order of an hour during which the average auroral Maxwellian characteristic energy stays relatively constant but the energy flux decreases progressively during the event. A possible explanation for this behaviour in terms of an injection of particles into a magnetospheric 'bottle' near the midnight meridian and the progressive precipitation out of the bottle during the pulsating event is suggested. (auth)

  3. Aurora-A overexpression enhances cell-aggregation of Ha-ras transformants through the MEK/ERK signaling pathway

    International Nuclear Information System (INIS)

    Tseng, Ya-Shih; Lee, Jenq-Chang; Huang, Chi-Ying F; Liu, Hsiao-Sheng

    2009-01-01

    Overexpression of Aurora-A and mutant Ras (Ras V12 ) together has been detected in human bladder cancer tissue. However, it is not clear whether this phenomenon is a general event or not. Although crosstalk between Aurora-A and Ras signaling pathways has been reported, the role of these two genes acting together in tumorigenesis remains unclear. Real-time PCR and sequence analysis were utilized to identify Ha- and Ki-ras mutation (Gly -> Val). Immunohistochemistry staining was used to measure the level of Aurora-A expression in bladder and colon cancer specimens. To reveal the effect of overexpression of the above two genes on cellular responses, mouse NIH3T3 fibroblast derived cell lines over-expressing either Ras V12 and wild-type Aurora-A (designated WT) or Ras V12 and kinase-inactivated Aurora-A (KD) were established. MTT and focus formation assays were conducted to measure proliferation rate and focus formation capability of the cells. Small interfering RNA, pharmacological inhibitors and dominant negative genes were used to dissect the signaling pathways involved. Overexpression of wild-type Aurora-A and mutation of Ras V12 were detected in human bladder and colon cancer tissues. Wild-type Aurora-A induces focus formation and aggregation of the Ras V12 transformants. Aurora-A activates Ral A and the phosphorylation of AKT as well as enhances the phosphorylation of MEK, ERK of WT cells. Finally, the Ras/MEK/ERK signaling pathway is responsible for Aurora-A induced aggregation of the Ras V12 transformants. Wild-type-Aurora-A enhances focus formation and aggregation of the Ras V12 transformants and the latter occurs through modulating the Ras/MEK/ERK signaling pathway

  4. Thermal mechanism of prepeak formation in Pulsed Glow Discharge

    Science.gov (United States)

    Voronov, Maxim; Hoffmann, Volker; Steingrobe, Tobias; Buscher, Wolfgang; Engelhard, Carsten; Storey, Andrew; Ray, Steven; Hieftje, Gary

    2012-10-01

    A microsecond Pulsed Glow Discharge (μs PGD) in a Grimm-type source is characterized by the so-called ``prepeak,'' which is a spike in both electrical current and emission intensity at the leading edge of the discharge pulse. The prepeak is followed by synchronized vibrations of the current and the emission. To understand the nature of these phenomena, a microphone was inserted into the discharge chamber. Acoustical waves were detected and found to be in correlation with the measured vibrations. This points to a thermal mechanism for prepeak formation: the gas is heated in the leading edge of the discharge pulse and then expanded. To prove this suggestion, a Monte-Carlo based model was developed to simulate the evolution of Ar concentration, temperature, and flow in time and space. Potentially, the model could be used for gas simulations in a wide range of different applications. Here, the model is incorporated into an existing but modified model of the μs PGD in a Grimm-type plasma excitation source. Results of the simulations confirm that the thermal mechanism is responsible for the formation of the electrical prepeak and the pressure waves.

  5. Study on the onset of DC diaphragm glow discharge

    International Nuclear Information System (INIS)

    Jin, Xinglong; Wang, Xiaoyan; Zhang, Hongmei; Ren, Hongxia

    2013-01-01

    In this paper, the DC diaphragm glow discharge (DGD) occurred around the small hole on quartz tube between two submersed graphite electrodes and the onset of DGD was systematically investigated. It was found that critical voltage (V D ) decreased with the increasing conductivity, and then maintained at about 620 V. When the hole diameter increased from 1.0 mm to 2.5 mm, H 2 O 2 formation and AO discoloration in anolyte increased with the increase of the hole diameter. In addition, the effect of electrolyte constituents on H 2 O 2 formation and AO discoloration in anolyte induced by DGD was also studied. The concentration of H 2 O 2 and AO discoloration in anolyte was close in inert electrolyte such as Na 2 SO 4 and Na 2 HPO 4 solution. The concentration of H 2 O 2 and AO discoloration rate in Na 2 CO 3 and NaAc solution was lower than those in Na 2 SO 4 and Na 2 HPO 4 solution, due to their capture ability for ·OH. However, NaCl showed enhancing effect on AO discoloration, although it consumed a certain amount of H 2 O 2 . The energy efficiencies of AO discoloration and H 2 O 2 formation were also compared with those of other DGD reactor.

  6. Temporal evolution of the after glow plasma conductivity

    International Nuclear Information System (INIS)

    Surmeian, A.; Diplasu, C.; Musa, G.; Popescu, I-Iovitz

    2001-01-01

    Due to their exhibited advantages over continuous and RF glows, the pulsed discharges gain more attention in a wide variety of application fields, like film deposition, plasma chemistry, semiconductor processing, etc. For this reason, fast time-resolved experimental methods need to be developed in order to control the main parameters of the high voltage pulsed plasmas. It is well known that electric probes present major advantages over many other diagnostic techniques for studying plasma parameters, but the use of these probes in the high voltage pulsed plasmas encounters enormous difficulties. One of them is the issue of galvanic insulation of the probe during the high voltage pulse. Also, the plasma potential may change rapidly, inducing spurious currents in the probe. Other problems could arise in the afterglow when the probe can exert great influence over the plasma potential by the current that it draws from the plasma. In this paper, we proposed a new method for the determination of the electrical conductivity of the afterglow of the high voltage pulsed discharges, using a low frequency RF plane probe. The application of a small low frequency signal to the plane probe could successfully eliminate all the disadvantages mentioned above. (authors)

  7. Iron nitride films formed in a r. f. glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Li, J.L.; O' Keefe, T.J.; James, W.J. (Depts. of Chemistry and Metallurgical Engineering and Graduate Center for Materials Research, Univ. of Missouri-Rolla (United States))

    1992-12-30

    Fe[sub 2]N and Fe[sub 3]N films were deposited on an r.f. glow discharge by introducing Fe(CO)[sub 5] and NH[sub 3] into the reactor. The iron nitride films thus formed exhibited sheet conductivities in the range of 10[sup 2]-10[sup 3] ohm[sup -1] cm[sup -1]. They exhibited microhardness ranging from 578 to 659 kg mm[sup -2] on glass slides. The effects of the deposition temperature and the nature of the substrate material on the structure and composition of the films were investigated. An Fe[sub 4]N layer was formed on iron substrates at 400degC in the plasma nitriding process using NH[sub 3] as the gas source. The Fe[sub 4]N layer exhibited a microhardness of 230 kg mm[sup -2]. The effect of the temperature on the formation of the nitrided layer is discussed. (orig.).

  8. Degradation of Anionic Dye Eosin by Glow Discharge Electrolysis Plasma

    International Nuclear Information System (INIS)

    Gao Jinzhang; Ma Dongping; Guo Xiao; Wang Aixiang; Fu Yan; Wu Jianlin; Yang Wu

    2008-01-01

    This paper describes a novel method for the degradation of eosin by using glow discharge electrolysis (GDE). The effects of various parameters on the removal efficiency were studied. It was found that the eosin degradation could be raised considerably by increasing the applied voltage and the initial concentration, or by decreasing pH of the aqueous solution. Fe 2+ ion had an evident accelerating effect on the eosin degradation. The degradation process of eosin obeyed a pseudo-first-order reaction. The relationship between the degradation rate constant k and the reaction temperature T could be expressed by Arrhenius equation with which the apparent activation energy Ea of 14.110 kJ. mol -1 and the pre-exponential factor ko of 2.065x10 -1 min -1 were obtained, too. The determination of hydroxyl radical was carried out by using N,N-dimethyl-p-nitrosoaniline (RNO) as a scavenger. The results showed that the hydroxyl radical plays an important role in the degradation process.

  9. Degradation of Anionic Dye Eosin by Glow Discharge Electrolysis Plasma

    Science.gov (United States)

    Gao, Jinzhang; Ma, Dongping; Guo, Xiao; Wang, Aixiang; Fu, Yan; Wu, Jianlin; Yang, Wu

    2008-08-01

    This paper describes a novel method for the degradation of eosin by using glow discharge electrolysis (GDE). The effects of various parameters on the removal efficiency were studied. It was found that the eosin degradation could be raised considerably by increasing the applied voltage and the initial concentration, or by decreasing pH of the aqueous solution. Fe2+ ion had an evident accelerating effect on the eosin degradation. The degradation process of eosin obeyed a pseudo-first-order reaction. The relationship between the degradation rate constant k and the reaction temperature T could be expressed by Arrhenius equation with which the apparent activation energy Ea of 14.110 kJ. mol-1 and the pre-exponential factor ko of 2.065×10-1 min-1 were obtained, too. The determination of hydroxyl radical was carried out by using N,N-dimethyl-p-nitrosoaniline (RNO) as a scavenger. The results showed that the hydroxyl radical plays an important role in the degradation process.

  10. Bulk plasma properties in the pulsed glow discharge

    International Nuclear Information System (INIS)

    Jackson, Glen P.; King, Fred L.

    2003-01-01

    This work focuses on the spatial and temporal characteristics of a glow discharge plasma operated with power pulses of 5 ms in duration at 25% duty cycle. Interpretation of emission data provides insight into the nature of the plasma at each instant of a typical pulse cycle and at each position in space. Because the bulk plasma properties affect the distribution of excited energy levels of the sputtered atoms, an improved understanding of the plasma affords the ability to select conditions that enhance analytically important emission lines. Optical emission spectroscopy was used to determine the relative populations of excited states for atoms and ions during the initial breakdown, the steady state and the recombining periods of the discharge pulse cycle. The plasma is highly ionizing in nature at the time of breakdown--with lower excited states being overpopulated--before reaching the steady state, or plateau, period, also ionizing in nature. These behaviors arise from a loss of charged particles and photons to the surroundings that shifts the plasma away from Saha and Boltzmann balances during these periods. The post-pulse period typically displays recombining behavior, characterized by population inversion for selected species--except for regions close to the cathode, where electrons and ions are lost by diffusion and are not available for recombination. The sputtered analyte atom emissions closely mimic those of the plasma bath gas, except that their emissions persevere for longer in the recombining after-peak period than do the discharge gas species

  11. Effects of time-temperature profiles on glow curves of germanium-doped optical fibre

    Science.gov (United States)

    Lam, S. E.; Alawiah, A.; Bradley, D. A.; Mohd Noor, N.

    2017-08-01

    The Germanium (Ge) doped silica optical fibres have demonstrated the great potential to be developed as a thermoluminescent (TL) dosimeter that can be used in various applications in radiotherapy, diagnostic radiology, UV dosimetry system and food irradiation industry. Different time-temperature profile (TTP) parameters of the TL reader have been employed by many researchers in various of TL studies. Nevertheless, none of those studies adequately addressed the effects of the reader's preheat temperature and heating rate on the kinetic parameters of the TL glow curve specifically, the Ge-doped silica optical fibres. This research addresses the issue of TTP parameters with special attention to the determination of the kinetic parameters of the glow curve. The glow curve responses were explored and the kinetic parameters were analyzed by the WinGCF software, to show the effect of the preheat temperature and heating rate of the reader on Ge-doped fibre irradiated with 18 Gy of 6 MV photons radiation. The effect of TTP parameters was discussed and compared against the commercial fibre and tailored made fibre of 6 mol% Ge-doped of flat and cylindrical shape. The deconvolution of glow peaks and the kinetic parameters were obtained by the WinGCF software. This enables to fit accurately (1.5%glow curves. A positive, moderate linear relationship exists between the TL response and the heating rate when the specific preheat temperature was used to read commercial fibre (50 °C) and cylindrical fibre (80 °C and 160 °C). It is found that the glow peaks of cylindrical fibre exhibit the highest peak integral as compared to flat and commercial fibres. This study revealed the possible relationship between the reader's TTP parameters and the kinetic parameters of TL glow curves for the commercial and tailored made Ge-doped silica optical fibres.

  12. In-flight observation of long duration gamma-ray glows by aircraft

    Science.gov (United States)

    Kochkin, Pavlo; (Lex) van Deursen, A. P. J.; de Boer, Alte; Bardet, Michiel; Allasia, Cedric; Boissin, Jean Francois; Ostgaard, Nikolai

    2017-04-01

    The Gamma-Ray Glow is a long-lasting (several seconds to minutes) X- and gamma radiation presumably originated from high-electric field of thunderclouds. Such glows were previously observed by aircraft, balloons, and from the ground. When detected on ground with other particles, i.e. electrons and neutrons, they are usually called Thunderstorm Ground Enhancements (TGEs). Their measured spectra are often consistent with Relativistic Runaway Electron Avalanche (RREA) mechanism. That is why RREA is a commonly accepted explanation for their existence. The gamma-ray glows are observed to be interrupted by lightning discharge, which terminates the high-electric field region. In January 2016 an Airbus A340 factory test aircraft was performing intentional flights through thunderstorms over Northern Australia. The aircraft was equipped with a dedicated in-flight lightning detection system called ILDAS (http://ildas.nlr.nl). The system also contained two scintillation detectors each with 38x38 mm cylinder LaBr3 crystals. While being at 12 km altitude the system detected a gamma-ray flux enhancement 30 times the background counts. It lasted for 20 seconds and was abruptly terminated by a lightning flash. The flash hit the aircraft and its parameters were recorded with 10 ns sampling time including gamma radiation. Ground-based lightning detection network WWLLN detected 4 strikes in the nearby region, all in association with the same flash. The ILDAS system recorded the time-resolved spectrum of the glow. In 6 minutes, after making a U-turn, the aircraft passed the same glow region. Smaller gamma-ray enhancement was again detected. In this presentation we will show the mapped event timeline including airplane, gamma-ray glow, WWLLN, and cloud data. We will discuss the glow's properties, i.e. intensity and differential spectrum, and its possible origin. This result will also be compared to previously reported observations.

  13. Thermoluminescence glow curve analysis and CGCD method for erbium doped CaZrO{sub 3} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, Ratnesh, E-mail: 31rati@gmail.com [Department of Physics, Bhilai Institute of Technology, Raipur, 493661 (India); Chopra, Seema [Department Physics, G.D Goenka Public School (India)

    2016-05-06

    The manuscript report the synthesis, thermoluminescence study at fixed concentration of Er{sup 3+} (1 mol%) doped CaZrO{sub 3} phosphor. The phosphors were prepared by modified solid state reaction method. The powder sample was characterized by thermoluminescence (TL) glow curve analysis. In TL glow curve the optimized concentration in 1mol% for UV irradiated sample. The kinetic parameters were calculated by computerized glow curve deconvolution (CGCD) techniaue. Trapping parameters gives the information of dosimetry loss in prepared phosphor and its usability in environmental monitoring and for personal monitoring. CGCD is the advance tool for analysis of complicated TL glow curves.

  14. Recent laser experiments on the Aurora KrF/ICF laser system

    International Nuclear Information System (INIS)

    Turner, T.P.; Jones, J.E.; Czuchlewski, S.J.; Watt, R.G.; Thomas, S.J.; Kang, M.; Tallman, C.R.; Mack, J.M.; Figueira, J.F.

    1990-01-01

    The Aurora KrF/ICF Laser Facility at Los Alamos is operational at the kilojoule-level for both laser and target experiments. We report on recent laser experiments on the system and resulting system improvements. 3 refs., 4 figs

  15. 76 FR 65216 - Beacon Medical Services, LLC, Aurora, CO; Notice of Negative Determination Regarding Application...

    Science.gov (United States)

    2011-10-20

    ... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-80,219] Beacon Medical Services... workers and former workers of Beacon Medical Services, LLC, Aurora, Colorado (Beacon Medical Services... published in the Federal Register on July 8, 2011 (76 FR 40401). The workers of Beacon Medical Services are...

  16. Cancer Cell Resistance to Aurora Kinase Inhibitors: Identification of Novel Targets for Cancer Therapy

    Czech Academy of Sciences Publication Activity Database

    Hrabáková, Rita; Kollaredy, M.; Tylečková, Jiřina; Halada, Petr; Hajdúch, M.; Gadher, S. J.; Kovářová, Hana

    2013-01-01

    Roč. 12, č. 1 (2013), s. 455-469 ISSN 1535-3893 R&D Projects: GA MŠk LC07017 Institutional support: RVO:67985904 ; RVO:61388971 Keywords : Aurora kinase inhibitors * resistance * p53 * apoptosis Subject RIV: CE - Biochemistry Impact factor: 5.001, year: 2013

  17. Aurora kinase A is essential for correct chromosome segregation in mouse zygote

    Czech Academy of Sciences Publication Activity Database

    Kovaříková, V.; Burkus, J.; Rehák, P.; Brzáková, Adéla; Šolc, Petr; Baran, V.

    2016-01-01

    Roč. 24, č. 3 (2016), s. 326-337 ISSN 0967-1994 R&D Projects: GA MŠk ED2.1.00/03.0124 Institutional support: RVO:67985904 Keywords : apoptosis * aurora A * MLN8237 * mouse zygote * spindle Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.053, year: 2016

  18. GATEWAY Demonstrations: OLED Lighting in the Offices of Aurora Lighting Design, Inc.

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Naomi J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-03-31

    At the offices of Aurora Lighting Design, Inc., in Grayslake, IL, the GATEWAY program conducted its first investigation involving OLED lighting. The project experienced several challenges, but also highlighted a number of promising attributes – which indicate that with continued improvements in efficacy, longevity, size, and flexibility, OLEDs could provide a new tool for creative and effective lighting.

  19. Discovery of Salamandra atra aurorae (Trevisan, 1982 on the Altopiano di Vezzena, Trentino (Northeastern Italy

    Directory of Open Access Journals (Sweden)

    Wouter Beukema

    2008-05-01

    Full Text Available Aurora’s Alpine Salamander is a limited distributed subspecies endemic to the Altopiano di Asiago, Veneto. In the current paper the occurrence of Salamandra atra aurorae is described for the Altopiano di Vezzena, Trentino. The aim of this paper is to review the distribution as well as to comment on the conservational status of the subspecies in Trentino.

  20. Aurora T: a Monte Carlo code for transportation of neutral atoms in a toroidal plasma

    International Nuclear Information System (INIS)

    Bignami, A.; Chiorrini, R.

    1982-01-01

    This paper contains a short description of Aurora code. This code have been developed at Princeton with Monte Carlo method for calculating neutral gas in cylindrical plasma. In this work subroutines such one can take in account toroidal geometry are developed

  1. Radar and photometric measurements of an intense type A red aurora

    Science.gov (United States)

    Robinson, R. M.; Mende, S. B.; Vondrak, R. R.; Kozyra, J. U.; Nagy, A. F.

    1985-01-01

    On the evening of March 5, 1981, an intense, type A red aurora appeared over southern Alaska. Radar and photometric measurements were made of the aurora from the Chatanika radar site. The line of sight intensity of the 630.0-nm emissions exceeded 150 kR and was accompanied by enhanced emissions at 486.1 and 427.8 nm. The Chatanika radar measured electron densities of 10 to the 6th per cu cm and electron temperatures of 6000 K at an altitude of 400 km and an invariant latitude of 59 deg in association with the aurora. Comparison of optical and radar measurements indicated that the 630.0-nm emissions were produced to a large degree by thermal excitation of O(1D) in the region of high electron temperatures and densities. Model calculations indicate that the observed density and temperature enhancements and the related optical emissions were the results of a relatively short duration (5-10 min) pulse of precipitating, low-energy (about 30 eV) electrons. Whereas conventional stable auroral red arcs are associated with a gradual decrease in ring current energy density during the recovery phase of a magnetic storm, the type A red aurora may be produced by impulsive ring current energy loss during the main phase.

  2. Analysis of soils by glow discharge mass spectrometry

    International Nuclear Information System (INIS)

    Duckworth, D.C.; Barshick, C.M.; Smith, D.H.

    1993-01-01

    The analysis of soils by conventional solution-based techniques, such as inductively coupled plasma and thermal ionization mass spectrometry, is complicated by the need for sample dissolution or the combination of a solids atomizer with an auxiliary ionization source. Since time is an important consideration in waste remediation, there exists a need for a method of rapidly analysing many soil samples with little sample preparation; glow discharge mass spectrometry (GDMS) has the potential to meet this need. Because GDMS is a bulk solids technique, sample preparation is simplified in comparison to other methods. Even with the most difficult samples (geological materials, such as soils and volcanic rock), all that is required is grinding, drying and mixing with a conducting host material prior to electrode formation. As a first test of GDMS for soil analysis, a National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) was analysed by direct current GDMS. Fifty-one elements were quantified from a single cathode using ion beam ratios and ''standard'' relative elemental sensitivity factors (RSF). Average errors for the suite of elements were less than a factor of 4 and 1.4 for uncorrected and corrected values, respectively. User-generated RSF values were applied to the analysis of several elements in NIST SRM 2704 Buffalo River Sediment. In the absence of isobaric interferences, accuracies ranging from 0.6 to 73% were observed, demonstrating the potential of the technique for the determination of many elements. The presence of entrained water and inhomogeneity resulting from cathode preparation is thought to affect matrix-to-matrix reproducibility. While further success depends on developing means of circumventing mass spectral interferences and addressing factors affecting plasma chemistry, the immediate goal of developing a screening method for priority metals in soils was met. (Author)

  3. Swarm-Aurora: A web-based tool for quickly identifying multi-instrument auroral events

    Science.gov (United States)

    Chaddock, D.; Donovan, E.; Spanswick, E.; Knudsen, D. J.; Frey, H. U.; Kauristie, K.; Partamies, N.; Jackel, B. J.; Gillies, M.; Holmdahl Olsen, P. E.

    2016-12-01

    In recent years there has been a dramatic increase in ground-based auroral imaging systems. These include the continent-wide THEMIS-ASI network, and imagers operated by other programs including GO-Canada, MIRACLE, AGO, OMTI, and more. In the near future, a new Canadian program called TREx will see the deployment of new narrow-band ASIs that will provide multi-wavelength imaging across Western Canada. At the same time, there is an unprecedented fleet of international spacecraft probing geospace at low and high altitudes. We are now in the position to simultaneously observe the magnetospheric drivers of aurora, observe in situ the waves, currents, and particles associated with MI coupling, and the conjugate aurora. Whereas a decade ago, a single magnetic conjunction between one ASI and a low altitude satellite was a relatively rare event, we now have a plethora of triple conjunctions between imagers, low-altitude spacecraft, and near-equatorial magnetospheric probes. But with these riches comes a new level of complexity. It is often difficult to identify the many useful conjunctions for a specific line of inquiry from the multitude of conjunctions where the geospace conditions are often not relevant and/or the imaging is compromised by clouds, moon, or other factors. Swarm-Aurora was designed to facilitate and drive the use of Swarm in situ measurements in auroral science. The project seeks to build a bridge between the Swarm science community, Swarm data, and the complimentary auroral data and community. Swarm-Aurora (http://swarm-aurora.phys.ucalgary.ca) incorporates a web-based tool which provides access to quick-look summary data for a large array of instruments, with Swarm in situ and ground-based ASI data as the primary focus. This web interface allows researchers to quickly and efficiently browse Swarm and ASI data to identify auroral events of interest to them. This allows researchers to be able to easily and quickly identify Swarm overflights of ASIs that

  4. The measurement and analysis of electric fields in glow discharge plasmas

    International Nuclear Information System (INIS)

    Lawler, J.E.; Doughty, D.A.

    1994-01-01

    Interest in glow discharge plasmas has remained high for many decades because of their widespread application as a source of incoherent and coherent light, in plasma processing materials, in pulsed power devices, and in other technologies. Plasma etching of semiconductors and various plasma deposition process emerged as major applications during the 1980s. The technological significance of plasma processing is described in Plasma Processing of Materials. More fundamental work on glow discharges also advanced greatly during the 1980s. For example, substantial progress was made through the use of laser diagnostics to study glow discharges and as a result of the dramatically increased computing power that became available in the 1980s to model glow discharges. Many of the laser diagnostics are described in Radiative Processes in Discharge Plasmas. Kinetic theory models, in particular, became far more sophisticated and realistic during the 1980s. This article is a review of recent work that used optical diagnostics to study electric fields in glow discharge plasmas. Alternative methods for measuring electric electric fields in plasmas include electron beam deflection and electrostatic probes. Optical techniques have important advantages over these methods: They can be used at higher pressures and discharge current densities than electron beam deflection; and they are noninvasive, unlike electrostatic probes. In addition, optical techniques are usually easier to apply in a highly pure system than either of the alternative methods. 46 refs., 23 figs., 1 tab

  5. The role of magnetic energy on plasma localization during the glow discharge under reduced pressure

    Directory of Open Access Journals (Sweden)

    Chodun Rafal

    2016-06-01

    Full Text Available In this work, we present the first results of our research on the synergy of fields, electric and magnetic, in the initiation and development of glow discharge under reduced pressure. In the two-electrode system under reduced pressure, the breakdown voltage characterizes a minimum energy input of the electric field to initiate and sustain the glow discharge. The glow discharge enhanced by the magnetic field applied just above the surface of the cathode influences the breakdown voltage decreasing its value. The idea of the experiment was to verify whether the contribution of potential energy of the magnetic field applied around the cathode is sufficiently effective to locate the plasma of glow discharge to the grounded cathode, which, in fact, is the part of a vacuum chamber wall (the anode is positively biased in this case. In our studies, we used the grounded magnetron unit with positively biased anode in order to achieve favorable conditions for the deposition of thin films on fibrous substrates such as fabrics for metallization, assuming that locally applied magnetic field can effectively locate plasma. The results of our studies (Paschen curve with the participation of the magnetic field seem to confirm the validity of the research assumption. What is the most spectacular - the glow discharge was initiated between introduced into the chamber anode and the grounded cathode of magnetron ‘assisted’ by the magnetic field (discharge did not include the area of the anode, which is a part of the magnetron construction.

  6. Changes in the artificial thermoluminescence glow curves of quartz associated with uranium deposits

    Energy Technology Data Exchange (ETDEWEB)

    Hochman, M.B.M.; Ypma, P.J.M.

    1988-01-01

    Previous laboratory-based studies have shown that quartz thermoluminescence (TL) glow curves change in intensity and shape in response to large radiation doses. Initially, low temperature peaks are sensitized though at gamma doses of greater than 10/sup 5/ - 10/sup 6/ kGy desensitization occurs. This study has examined the change in artificial TL in quartz at various distances from a uranium deposit. Such quartz has been subjected to varying palaeoradiation doses in a natural uranium rich environment. Quartz from an uranium rich environment shows that the 130/sup 0/C glow peak is the dominant glow peak in background radiation environments, though this peak decreases with increasing palaeoradiation dose. At doses greater than 10/sup 5/-10/sup 6/ kGy the 350/sup 0/C glow peak is the dominant glow peak in these quartz samples. An increase in E'/sub 1/ centre concentration also occurs from the least radiation affected sample to the most radiation affected sample. These results suggest that artificial TL is useful in uranium exploration.

  7. Aurora: Los Alamos multikilojoule angular-multiplexed KrF driver prototype for ICF

    International Nuclear Information System (INIS)

    Rosocha, L.A.; Hanlon, J.A.; McLeod, J.

    1987-01-01

    The Los Alamos National Laboratory (LANL) has participated in programs to apply high-power gas lasers to inertial confinement fusion (ICF). The bulk of this effort has been in the development of CO/sub 2/ laser systems and laser-plasma interaction experiments at a 10.6-μm wavelength. The main hardware element in this program is the Aurora KrF laser system, which is a prototype for using optical angular multiplexing and serial amplification by large electron-beam-driven KrF laser amplifiers to study KrF systems as potential fusion drivers. Aurora will serve as a test-bed for specific laser, optical, and electron-beam-pumping technology aspects of larger KrF fusion systems. The Aurora system is being built in two phases. The first-phase portion of the Aurora system contains all the main optical and laser elements from the front end to the final amplifier output. In the first phase, the front end output is replicated using aperture slicers and beam splitters to produce a 480-ns long pulse train consisting of 96 separate 5-ns pulses. This pulse train is encoded in angular separation, relayed through the amplifier chain by means of the centered optical system and the computer-controlled alignment station, and delivered to a diagnostic station which follows the main power amplifier [large aperture module (LAM)]. The second phase of the system contains the first-phase portion and the additional optical and target hardware needed to stack 48 of the 96 multiplexed and amplified beams into a single multikilojoule 5-ns pulse at the fusion target. The authors give a description of the Aurora system and discuss its present status

  8. Protein tyrosine phosphatase receptor delta acts as a neuroblastoma tumor suppressor by destabilizing the aurora kinase a oncogene

    LENUS (Irish Health Repository)

    Meehan, Maria

    2012-02-05

    Abstract Background Protein tyrosine phosphatase receptor delta (PTPRD) is a member of a large family of protein tyrosine phosphatases which negatively regulate tyrosine phosphorylation. Neuroblastoma is a major childhood cancer arising from precursor cells of the sympathetic nervous system which is known to acquire deletions and alterations in the expression patterns of PTPRD, indicating a potential tumor suppressor function for this gene. The molecular mechanism, however, by which PTPRD renders a tumor suppressor effect in neuroblastoma is unknown. Results As a molecular mechanism, we demonstrate that PTPRD interacts with aurora kinase A (AURKA), an oncogenic protein that is over-expressed in multiple forms of cancer, including neuroblastoma. Ectopic up-regulation of PTPRD in neuroblastoma dephosphorylates tyrosine residues in AURKA resulting in a destabilization of this protein culminating in interfering with one of AURKA\\'s primary functions in neuroblastoma, the stabilization of MYCN protein, the gene of which is amplified in approximately 25 to 30% of high risk neuroblastoma. Conclusions PTPRD has a tumor suppressor function in neuroblastoma through AURKA dephosphorylation and destabilization and a downstream destabilization of MYCN protein, representing a novel mechanism for the function of PTPRD in neuroblastoma.

  9. In vivo FRET imaging revealed a regulatory role of RanGTP in kinetochore-microtubule attachments via Aurora B kinase.

    Directory of Open Access Journals (Sweden)

    Yoke-Peng Lee

    Full Text Available Under the fluctuating circumstances provided by the innate dynamics of microtubules and opposing tensions resulted from microtubule-associated motors, it is vital to ensure stable kinetochore-microtubule attachments for accurate segregation. However, a comprehensive understanding of how this regulation is mechanistically achieved remains elusive. Using our newly designed live cell FRET time-lapse imaging, we found that post-metaphase RanGTP is crucial in the maintenance of stable kinetochore-microtubule attachments by regulating Aurora B kinase via the NES-bearing Mst1. More importantly, our study demonstrates that by ensuring stable alignment of metaphase chromosomes prior to segregation, RanGTP is indispensible in governing the genomic integrity and the fidelity of cell cycle progression. Our findings suggest an additional role of RanGTP beyond its known function in mitotic spindle assembly during the prometaphase-metaphase transition.

  10. Polar cap particle precipitation and aurora: Review and commentary

    Science.gov (United States)

    Newell, Patrick T.; Liou, Kan; Wilson, Gordon R.

    2009-02-01

    presence of ions does not fit the properties of polar rain, which can in any event be nearly absent for northward interplanetary magnetic field). One theory is that such arcs are associated with merging tailward of the cusp. Both of these common types of sun-aligned arcs fade within about 30 min of a southward IMF turning. The third, and rarest, category of sun-aligned arcs are intense, well detached from the auroral oval, contain plasma sheet origin ion precipitation as well as electrons, and persist for hours after a southward turning. These intense detached sun-aligned arcs can rapidly cross the polar cap, sometimes multiple times. Most events discussed in the literature as "theta-aurora" do not fit into this category (for example, although they may appear detached in images, they abut the oval in particle data, and do not have the persistence of detached events under southward IMF turnings). It is possible that no single theory can account for all three types of sun-aligned arcs. Solar energetic particle (SEP) events are at times used to demarcate polar cap open/closed boundaries. Although this works at times, examples exist where this method fails (e.g., very quiet conditions for which SEP reaches below L=4), and the method should be used with caution. Finally, it is shown that, although it is rare, the polar cap can at times completely close.

  11. Gas Breakdown of Radio Frequency Glow Discharges in Helium at near Atmospheric Pressure

    International Nuclear Information System (INIS)

    Liu Xinkun; Xu Jinzhou; Cui Tongfei; Guo Ying; Zhang Jing; Shi Jianjun

    2013-01-01

    A one-dimensional self-consistent fluid model was developed for radio frequency glow discharge in helium at near atmospheric pressure, and was employed to study the gas breakdown characteristics in terms of breakdown voltage. The effective secondary electron emission coefficient and the effective electric field for ions were demonstrated to be important for determining the breakdown voltage of radio frequency glow discharge at near atmospheric pressure. The constant of A was estimated to be 64±4 cm −1 Torr −1 , which was proportional to the first Townsend coefficient and could be employed to evaluate the gas breakdown voltage. The reduction in the breakdown voltage of radio frequency glow discharge with excitation frequency was studied and attributed to the electron trapping effect in the discharge gap

  12. The experience with JET's combined dc/Rf glow discharge cleaning (GDC) system

    International Nuclear Information System (INIS)

    Pearce, R.J.H.; Andrew, P.; Bryan, S.

    1996-01-01

    The JET Tokamak was fitted with four new electrodes of novel design, each powered from individual computer controlled dc and RF supplies. Details of enhancements and problems from 15 months experience with the system are outlined. Experiments were performed to assess the effect of RF on the glow discharge characteristics, and to establish stable glow at low pressure and high voltage. JET combined RF/dc glow discharge cleaning (GDC) had no significant advantages over pure dc GDC, provided highly stable dc current control was obtained. In fact, the mechanically weak electrode inductor spiral required to allow RF posed a distinct disadvantage. The electrodes were converted to simple plates, following damage caused by halo currents during Tokamak plasma disruptions. The performance of these electrodes was assessed. Future developments in the JET GDC system are outlined. (Author)

  13. Does exclusion of protest zeros and warm-glow bidders cause selection bias in Contingent Valuation?

    DEFF Research Database (Denmark)

    Grammatikopoulou, Ioanna; Olsen, Søren Bøye; Pouta, Eija

    A great issue of concern in valuation studies is whether respondents provide trustworthy and reliable answers conditional on the perceived information. Respondent may report either a higher than the true Willingness-To-Pay (WTP) due to warm glow or embedding effects or zero WTP which is lower than...... the true WTP due to protest behavior. We conduct a contingent valuation study to estimate the WTP for conserving a Natura 2000 wetland area in Greece. We find that 54% of the positive bidders exert warm glow motivations while 29% of all responses can be classified as protest zero bids. We employ three....... Our findings show that removal of warm glow positive bidders does not distort the WTP estimate in any significant way. However, using the same approach for protest zero bidders, we find strong evidence of selection bias associated with removal of protest zero responses. Specifically, WTP estimates...

  14. Self-consistent model for pulsed direct-current N2 glow discharge

    International Nuclear Information System (INIS)

    Liu Chengsen

    2005-01-01

    A self-consistent analysis of a pulsed direct-current (DC) N 2 glow discharge is presented. The model is based on a numerical solution of the continuity equations for electron and ions coupled with Poisson's equation. The spatial-temporal variations of ionic and electronic densities and electric field are obtained. The electric field structure exhibits all the characteristic regions of a typical glow discharge (the cathode fall, the negative glow, and the positive column). Current-voltage characteristics of the discharge can be obtained from the model. The calculated current-voltage results using a constant secondary electron emission coefficient for the gas pressure 133.32 Pa are in reasonable agreement with experiment. (authors)

  15. Computerized glow curve deconvolution of thermoluminescent emission from polyminerals of Jamaica Mexican flower

    Science.gov (United States)

    Favalli, A.; Furetta, C.; Zaragoza, E. Cruz; Reyes, A.

    The aim of this work is to study the main thermoluminescence (TL) characteristics of the inorganic polyminerals extracted from dehydrated Jamaica flower or roselle (Hibiscus sabdariffa L.) belonging to Malvaceae family of Mexican origin. TL emission properties of the polymineral fraction in powder were studied using the initial rise (IR) method. The complex structure and kinetic parameters of the glow curves have been analysed accurately using the computerized glow curve deconvolution (CGCD) assuming an exponential distribution of trapping levels. The extension of the IR method to the case of a continuous and exponential distribution of traps is reported, such as the derivation of the TL glow curve deconvolution functions for continuous trap distribution. CGCD is performed both in the case of frequency factor, s, temperature independent, and in the case with the s function of temperature.

  16. Reduction of Cr(VI) in aqueous solution with DC diaphragm glow discharge

    International Nuclear Information System (INIS)

    Wang, Xiaoyan; Jin, Xinglong; Zhou, Minghua; Chen, Zhenhai; Deng, Kai

    2013-01-01

    This paper investigated the reduction of Cr(VI) in aqueous solution with direct current diaphragm glow discharge (DGD). The glow discharge sustained around the hole on a quartz tube which divided the electrolyte cell into two parts. The reduction efficiencies of Cr(VI) under different applied voltages, initial conductivities, hole diameters, hole numbers, initial pH values and initial concentrations were systematically studied. The results showed that the reduction efficiency of Cr(VI) increased with the increase of applied voltage, initial conductivity, hole diameter and hole number. The different initial pH values showed less effects on the reduction of Cr(VI). The reduction efficiency decreased with the increasing initial concentration. In addition, the simultaneous reduction of Cr(VI) and decolorization of acid orange (AO) with DGD were also fulfilled. Furthermore, the energy efficiency for Cr(VI) reduction with DGD was calculated and compared with those in photocatalysis and other glow discharge reactor

  17. Pre-exponential factor in general order kinetics of thermoluminescence and its influence on glow curves

    International Nuclear Information System (INIS)

    Sunta, C.M.; Ayta, W.E.F.; Chen, R.; Watanabe, S.

    1997-01-01

    A model of thermoluminescence kinetics based on a physically meaningful approach shows that the glow curve shapes undergo systematic changes with the change of trap occupancy (dose). In terms of the general order kinetics model it means that the kinetic order changes with sample dose. In parallel to the kinetic order, the pre-exponential factor also changes. In contrast to these results the glow curves calculated from the general order kinetics model show that the peak shape remains nearly constant when the trap occupancy is changed. When appropriately defined, the pre-exponential factor also has a fixed value independent of trap occupancy. In these respects the general order kinetics model, though empirical, seems to describe the glow peak behaviour quite successfully. However, regarding the peak temperature the theoretical results both from the physical as well as the empirical model seem to diverge from the experimental observations when the experimentally determined kinetics is non-first order. (author)

  18. Study of plasma characteristics in the cathode regime of a nitrogen glow discharge

    International Nuclear Information System (INIS)

    Margulis, Alvaro

    1987-01-01

    This research thesis reports the study of the cathode region, cathodic sheath and negative glow, of a nitrogen glow discharge. The author first presents general data regarding glow discharges, a description of the experimental installation, and measurements of discharge balancing. In the next part, he precisely describes spectroscopic methods, and the implementation of diagnoses from an experimental point of view as well as in terms of space resolution. Results are then presented and interpreted. Measurements concern space distributions of excited species, the determination of axial and radial concentrations of nitrogen ions, axial variations of rotational temperatures of the different species and variations of nitrogen ion vibrational temperature. The laser optogalvanic effect on the nitrogen molecular ion is resolved in time, and compared with the result of a theoretical model based on the mobility difference between the different nitrogen ions. Finally, the author compares experimental results on ion profiles along the discharge axis with results obtained with theoretical models [fr

  19. Removal of the codeposited carbon layer using He-O glow discharge

    International Nuclear Information System (INIS)

    Kunz, C.L.; Causey, R.A.; Clift, M.; Wampler, W.R.; Cowgill, D.F.

    2007-01-01

    In this study we examine the combination of a He-O glow discharge with heating as a possible technique to remove deuterium from TFTR tiles. Samples were cut from a relatively large area containing a uniform codeposited layer of deuterium and carbon. Auger/SEM was used to generate micrographs of each of the samples. The samples were also examined using Rutherford backscattering to determine the near surface composition. Individual samples were then exposed to a He-O glow discharge while being heated. After the exposure, the samples were returned for Auger/SEM and RBS of the same areas examined prior to the exposure. Comparing the samples before and after exposure revealed that the amount of the codeposited layer removed was significantly less than 1 μm. Removal rates this low would suggest that He-O glow discharge with heating is insufficient to remove the thick layers predicted for ITER in a timely fashion

  20. Time effectiveness of capillary effect improvement of ramie fabrics processed by RF glow discharging

    International Nuclear Information System (INIS)

    Wang Zhiwen; Wei Weixing; He Yanhe; Zhao Yuanqing; Pan Liyiji; Li Xuemei; Shi Shaodui; Li Guangxin

    2010-01-01

    The time effectiveness of capillary effect improvement of ramie fabrics processed by RF glow discharging was studied. The ramie fabrics were processed in fulfilling with different gas (O 2 , N 2 , Ar) by different parameters (such as pressure,power and time) plasma. The capillary effect of the ramie fabrics processed by RF glow discharging was tested at different time. The results indicate that the capillary effect of ramie fabrics processed by RF glow discharging has been improved, the improvement of the capillary effect firstly decrease rapidly, then slowly, and become stable after 15 day, it indicate that improvement of the ramie fabrics capillary has good time effectiveness, and the plasma parameter for the best capillary effect improvement of ramie fabric is 100 W and 40 Pa processed 20 min by oxygen plasma. (authors)

  1. Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches

    Science.gov (United States)

    Christophorou, L.G.; Hunter, S.R.

    1990-06-26

    An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc. 11 figs.

  2. Detrapping of tungsten nanoparticles in a direct-current argon glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Couëdel, L., E-mail: lenaic.couedel@univ-amu.fr; Kumar, K. Kishor; Arnas, C. [Laboratoire de Physique des Interactions Ioniques et Moléculaires, CNRS, Aix-Marseille Université, 13397 Marseille (France)

    2014-12-15

    Nanoparticles are grown from the sputtering of a tungsten cathode in a direct current argon glow discharge. Laser light scattering of a vertical laser sheet going through the plasma reveals that the dust particle cloud is compressed and pushed towards the anode during the discharge. Scanning electron microscopy images of substrates exposed to the plasma for given durations show that dust particles are continuously falling down on the anode during the discharge. These observations are explained by the fact that the electrostatic force at the negative glow-anode sheath boundary cannot balance the ion drag, gravity, and thermophoresis forces for particles of more than a few tens of nanometres in diameter.

  3. The Effects of Lamp Spectral Distribution on Sky Glow over Observatories

    Science.gov (United States)

    2015-01-01

    overhead sky glow as a function of distance up to 300 km, from a variety of lamp types, including common gas discharge lamps and several types of LED...distance up to 300 km, from a variety of lamp types, in- cluding common gas discharge lamps and several types of LED lamps . We conclude for both...MAR 2015 2. REPORT TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE The Effects of Lamp Spectral Distribution on Sky Glow

  4. Removal of a glowing spot from an image tube using laser radiation.

    Science.gov (United States)

    Gurski, T. R.

    1972-01-01

    A troublesome problem with the Kron electronograph has been the presence of a white glowing spot on the glass wall of the tube adjacent to the focus electrode. The procedure followed to eliminate the spot was to operate in the dark and apply voltage only to the focused electrode. Ruby laser radiation was unfocused, and its position was shifted on the electrode between laser shots until an effect was observed. This technique for removing the glowing spot should be applicable to other electronic image tubes.

  5. Thermoluminescence glow-curve deconvolution functions for mixed order of kinetics and continuous trap distribution

    International Nuclear Information System (INIS)

    Kitis, G.; Gomez-Ros, J.M.

    2000-01-01

    New glow-curve deconvolution functions are proposed for mixed order of kinetics and for continuous-trap distribution. The only free parameters of the presented glow-curve deconvolution functions are the maximum peak intensity (I m ) and the maximum peak temperature (T m ), which can be estimated experimentally together with the activation energy (E). The other free parameter is the activation energy range (ΔE) for the case of the continuous-trap distribution or a constant α for the case of mixed-order kinetics

  6. Binary and ternary gas mixtures for use in glow discharge closing switches

    Science.gov (United States)

    Hunter, S.R.; Christophorou, L.G.

    1988-04-27

    Highly efficient binary and ternary gas mixtures for use in diffuse glow discharge closing switches are disclosed. The binary mixtures are combinations of helium or neon and selected perfluorides. The ternary mixtures are combinations of helium, neon, or argon, a selected perfluoride, and a small amount of gas that exhibits enhanced ionization characteristics. These mixtures are shown to be the optimum choices for use in diffuse glow discharge closing switches by virtue if the combines physio-electric properties of the mixture components. 9 figs.

  7. Design and performance of large area monolithic electron guns for the Aurora KrF laser system

    International Nuclear Information System (INIS)

    Kang, M.; Rosocha, L.A.; Romero, V.O.; Van Haaften, F.W.; Brucker, J.P.

    1985-01-01

    Aurora is an inertial confinement fusion laser system using optical angular multiplexing and a chain of four cold cathode electron beam driven KrF laser amplifiers to produce 10 to 20 kJ of optical energy

  8. BAROMETRIC PRESSURE and Other Data from AURORA AUSTRALIS and Other Platforms from 19910106 to 19920306 (NODC Accession 9500152)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD) and other data were collected from Ship AURORA AUSTRALIS. The data was collected over a period spanning from January 6,...

  9. Identification of critical chemical features for Aurora kinase-B inhibitors using Hip-Hop, virtual screening and molecular docking

    Science.gov (United States)

    Sakkiah, Sugunadevi; Thangapandian, Sundarapandian; John, Shalini; Lee, Keun Woo

    2011-01-01

    This study was performed to find the selective chemical features for Aurora kinase-B inhibitors using the potent methods like Hip-Hop, virtual screening, homology modeling, molecular dynamics and docking. The best hypothesis, Hypo1 was validated toward a wide range of test set containing the selective inhibitors of Aurora kinase-B. Homology modeling and molecular dynamics studies were carried out to perform the molecular docking studies. The best hypothesis Hypo1 was used as a 3D query to screen the chemical databases. The screened molecules from the databases were sorted based on ADME and drug like properties. The selective hit compounds were docked and the hydrogen bond interactions with the critical amino acids present in Aurora kinase-B were compared with the chemical features present in the Hypo1. Finally, we suggest that the chemical features present in the Hypo1 are vital for a molecule to inhibit the Aurora kinase-B activity.

  10. THE RELATIONSHIP BETWEEN THE SEPTEMBER 2017 MARS GLOBAL AURORA EVENT AND CRUSTAL MAGNETIC FIELDS

    Science.gov (United States)

    Nasr, Camella-Rosa; Schneider, Nick; Connour, Kyle; Jain, Sonal; Deighan, Justin; Jakosky, Bruce; MAVEN/IUVS Team

    2018-01-01

    In September 2017, the Imaging UltraViolet Spectrograph (IUVS) on the MAVEN spacecraft observed global aurora on Mars caused by a surprisingly strong solar energetic particle event. Widespread “diffuse aurora” have previously been detected on Mars through more limited observations (Schneider et al., Science 350, (2015); DOI: 10.1126/science.aad0313), but recent observations established complete coverage of the observable portion of Mars’ nightside. The aurora was global due to Mars’s lack of a global magnetic field, which allowed energetic electrons from the Sun to directly precipitate into the atmosphere. On September 11th, IUVS detected aurora more than 25 times brighter than any prior IUVS observation, with high SNR detections of aurora at the limb and against the disk of the planet. Fainter auroral emission was seen around the nightside limb over 13 orbits spanning nearly 3 days.On September 14th, during the declining phase of the event, faint linear features and patches were detected by the spacecraft, which were higher than the noise floor, with a similar spatial distribution to “discrete aurora” patches observed on Mars by the SPICAM instrument on the Mars Express spacecraft (Bertaux et al., Nature 435, doi :10.1038/nature03603). Discrete aurora occur near areas of the crust affected by the magnetism left over from Mars’ once-strong dipole field. Emission is limited to regions of the crustal magnetic field where the field lines are likely to be open to solar wind interactions. Those regions are concentrated in Mars’ southern hemisphere centered on 180 degrees east longitude.We studied the localized emissions on 14 September to determine whether there might be a connection between the observed diffuse aurora event and discrete auroral processes. First, we investigated the localized emissions to confirm that the observed signal was consistent with expected auroral spectra. Second, their locations were projected on a map of the crustal magnetic

  11. The Rose-red Glow of Star Formation

    Science.gov (United States)

    2011-03-01

    The vivid red cloud in this new image from ESO's Very Large Telescope is a region of glowing hydrogen surrounding the star cluster NGC 371. This stellar nursery lies in our neighbouring galaxy, the Small Magellanic Cloud. The object dominating this image may resemble a pool of spilled blood, but rather than being associated with death, such regions of ionised hydrogen - known as HII regions - are sites of creation with high rates of recent star birth. NGC 371 is an example of this; it is an open cluster surrounded by a nebula. The stars in open clusters all originate from the same diffuse HII region, and over time the majority of the hydrogen is used up by star formation, leaving behind a shell of hydrogen such as the one in this image, along with a cluster of hot young stars. The host galaxy to NGC 371, the Small Magellanic Cloud, is a dwarf galaxy a mere 200 000 light-years away, which makes it one of the closest galaxies to the Milky Way. In addition, the Small Magellanic Cloud contains stars at all stages of their evolution; from the highly luminous young stars found in NGC 371 to supernova remnants of dead stars. These energetic youngsters emit copious amounts of ultraviolet radiation causing surrounding gas, such as leftover hydrogen from their parent nebula, to light up with a colourful glow that extends for hundreds of light-years in every direction. The phenomenon is depicted beautifully in this image, taken using the FORS1 instrument on ESO's Very Large Telescope (VLT). Open clusters are by no means rare; there are numerous fine examples in our own Milky Way. However, NGC 371 is of particular interest due to the unexpectedly large number of variable stars it contains. These are stars that change in brightness over time. A particularly interesting type of variable star, known as slowly pulsating B stars, can also be used to study the interior of stars through asteroseismology [1], and several of these have been confirmed in this cluster. Variable stars

  12. Spectral characteristics of aurorae connected with high-velocity flows of the solar wind from coronal holes

    International Nuclear Information System (INIS)

    Khviyuzova, T.A.; Leont'ev, S.V.

    1997-01-01

    Bright electron aurorae almost always followed by red lower edge occur when the Earth is being passed by high-velocity flows from coronal holes within the auroral range at the night meridian. In contrast to other types of the solar wind the high-velocity flows from coronal holes do not cause the occurrence of A type red polar aurorae, that is, the spectrum of electrons pouring into the Earth atmosphere in these cases is shifted towards higher energies

  13. Iridium Coating Deposited by Double Glow Plasma Technique — Effect of Glow Plasma on Structure of Coating at Single Substrate Edge

    International Nuclear Information System (INIS)

    Wu Wangping; Chen Zhaofeng; Liu Yong

    2012-01-01

    Double glow plasma technique has a high deposition rate for preparing iridium coating. However, the glow plasma can influence the structure of the coating at the single substrate edge. In this study, the iridium coating was prepared by double glow plasma on the surface of single niobium substrate. The microstructure of iridium coating at the substrate edge was observed by scanning electron microscopy. The composition of the coating was confirmed by energy dispersive spectroscopy and X-ray diffraction. There was a boundary between the coating and the substrate edge. The covered area for the iridium coating at the substrate edge became fewer and fewer from the inner area to the outer flange-area. The bamboo sprout-like particles on the surface of the substrate edge were composed of elemental niobium. The substrate edge was composed of the Nb coating and there was a transition zone between the Ir coating and the Nb coating. The interesting phenomenon of the substrate edge could be attributed to the effects of the bias voltages and the plasma cloud in the deposition chamber. The substrate edge effect could be mitigated or eliminated by adding lots of small niobium plates around the substrate in a deposition process. (plasma technology)

  14. Time sequence analysis of flickering auroras. I - Application of Fourier analysis. [in atmosphere

    Science.gov (United States)

    Berkey, F. T.; Silevitch, M. B.; Parsons, N. R.

    1980-01-01

    Using a technique that enables one to digitize the brightness of auroral displays from individual fields of a video signal, we have analyzed the frequency content of flickering aurora. Through the application of Fourier analysis to our data, we have found that flickering aurora contains a wide range of enhanced frequencies, although the dominant frequency enhancement generally occurs in the range 6-12 Hz. Each incidence of flickering that we observed was associated with increased radio wave absorption. Furthermore, we have found that flickering occurs in bright auroral surges, the occurrence of which is not limited to the 'breakup' phase of auroral substorms. Our results are interpreted in terms of a recently proposed theory of fluctuating double layers that accounts for a number of the observational features.

  15. Aurora multikilojoule KrF laser system prototype for inertial confinement fusion

    International Nuclear Information System (INIS)

    Rosocha, L.A.; Hanlon, J.A.; Mc Leod, J.; Kang, M.; Kortegaard, B.L.; Burrows, M.D.; Bowling, P.S.

    1987-01-01

    Aurora is the Los Alamos National Laboratory short-pulse, high-power, KrF laser system. It serves as an end-to-end technology demonstration for large-scale ultraviolet laser systems of interest for short wavelength, inertial confinement fusion (ICF) investigations. The systems is a prototype for using optical angular multiplexing and serial amplification by large electron-beam-driven KrF laser amplifiers to deliver stacked, 248-nm, 5-ns duration multikilojoule laser pulses to ICF targets using an --1-km-long optical beam path. The entire Aurora KrF laser system is described and the design features of the following major system components are summarized: front-end lasers, amplifier train, multiplexer, optical relay train, demultiplexer, target irradiation apparatus, and alignment and controls systems

  16. Macro-micro interlocked simulation algorithm: an exemplification for aurora arc evolution

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Tetsuya [University of Hyogo, Kobe 650-0044 (Japan); Hasegawa, Hiroki; Ohno, Nobuaki [Japan Agency for Marine-Earth Science and Technology, Yokohama 236-0001 (Japan)], E-mail: sato@hq.u-hyogo.ac.jp

    2009-01-01

    Using an innovative holistic simulation algorithm that can self-consistently treat a system that evolves as cooperation between macroscopic and microscopic processes, the evolution of a colorful aurora arc is beautifully reproduced as the result of cooperation between the global field-aligned feedback instability of the coupled magnetosphere-ionosphere system and the ensuing microscopic ion-acoustic instability that generates electric double layers and accelerates aurora electrons. These results are in agreement with rocket and satellite observations. This shows that the proposed holistic algorithm could be a reliable tool to reveal complex real dramatic events and become, in the near future, a viable scientifically secure prediction tool for natural disasters such as earthquakes, landslides and floods caused by typhoons.

  17. Computer control system of the superconducting SR-light source ''Aurora''

    International Nuclear Information System (INIS)

    Yamada, H.

    1989-01-01

    The Aurora is a compact SR-light system optimized for x-ray lithography. The system includes a superconducting electron storage ring, a 150-MeV race track microtron as an injector, and light beamlines. The SR-ring features a single magnet body, in which the 650-MeV electron beam orbits a true circular trajectory of 1 m diameter. The computer control system developed for Aurora has a three-level hierarchical architecture. The top level is the Central Intelligence System, and the second an Autonomic Control System (ACS). The bottom is an assembly of distributed local controllers linked to the ACS level through optical fibers. This system provides fully automatic and remote operation, and a powerful machine study capability through the associated man--machine console and the interpretive operation language

  18. Computer control system of the superconducting SR-light source ``Aurora''

    Science.gov (United States)

    Yamada, Hironari

    1989-07-01

    The Aurora is a compact SR-light system optimized for x-ray lithography. The system includes a superconducting electron storage ring, a 150-MeV race track microtron as an injector, and light beamlines. The SR-ring features a single magnet body, in which the 650-MeV electron beam orbits a true circular trajectory of 1 m diameter. The computer control system developed for Aurora has a three-level hierarchical architecture. The top level is the Central Intelligence System, and the second an Autonomic Control System (ACS). The bottom is an assembly of distributed local controllers linked to the ACS level through optical fibers. This system provides fully automatic and remote operation, and a powerful machine study capability through the associated man-machine console and the interpretive operation language.

  19. Did Aboriginal Australians record a simultaneous eclipse and aurora in their oral traditions?

    Science.gov (United States)

    Fuller, Robert S.; Hamacher, Duane W.

    2017-12-01

    We investigate an Australian Aboriginal cultural story that seems to describe an extraordinary series of astronomical events occurring at the same time. We hypothesise that this was a witnessed natural event and explore natural phenomena that could account for the description. We select a thunderstorm, total solar eclipse, and strong Aurora Australis as the most likely candidates, then conclude a plausible date of 764 CE. We evaluate the different factors that would determine whether all these events could have been visible, include meteorological data, alternative total solar eclipse dates, solar activity cycles, aurorae appearances, and sky brightness during total solar eclipses. We conduct this study as a test-case for rigorously and systematically examining descriptions of rare natural phenomena in oral traditions, highlighting the difficulties and challenges with interpreting this type of hypothesis.

  20. A numerical solution of the coupled proton-H atom transport equations for the proton aurora

    International Nuclear Information System (INIS)

    Basu, B.; Jasperse, J.R.; Grossbard, N.J.

    1990-01-01

    A numerical code has been developed to solve the coupled proton-H atom linear transport equations for the proton aurora. The transport equations have been simplified by using plane-parallel geometry and the forward-scattering approximations only. Otherwise, the equations and their numerical solutions are exact. Results are presented for the particle fluxes and the energy deposition rates, and they are compared with the previous analytical results that were obtained by using additional simplifying approximations. It is found that although the analytical solutions for the particle fluxes differ somewhat from the numerical solutions, the energy deposition rates calculated by the two methods agree to within a few percent. The accurate particle fluxes given by the numerical code are useful for accurate calculation of the characteristic quantities of the proton aurora, such as the ionization rates and the emission rates

  1. Proteomic analysis of human metaphase chromosomes reveals Topoisomerase II alpha as an Aurora B substrate

    DEFF Research Database (Denmark)

    Morrison, Ciaran; Henzing, Alexander J; Jensen, Ole Nørregaard

    2002-01-01

    B in the presence of radioactive ATP. Immunoblot analysis confirmed the HeLa scaffold fraction to be enriched for known chromosomal proteins including CENP-A, CENP-B, CENP-C, ScII and INCENP. Mass spectrometry of bands excised from one-dimensional polyacrylamide gels further defined the protein......The essential Aurora B kinase is a chromosomal passenger protein that is required for mitotic chromosome alignment and segregation. Aurora B function is dependent on the chromosome passenger, INCENP. INCENP, in turn, requires sister chromatid cohesion for its appropriate behaviour. Relatively few...... composition of the extracted chromosome fraction. Cloning, fluorescent tagging and expression in HeLa cells of the putative GTP-binding protein NGB/CRFG demonstrated it to be a novel mitotic chromosome protein, with a perichromosomal localisation. Identi fication of the protein bands corresponding to those...

  2. Properties of the positive column of a glow discharge in flowing hydrogen

    International Nuclear Information System (INIS)

    Brunet, H.; Rocca Serra, J.; Mabru, M.

    1981-01-01

    Results of a theoretical model for predicting the effects of gas flow on the properties of the positive column in a glow discharge are presented. A cylindrical discharge at low pressure ( 2 molecules and H atoms produced by the discharge are calculated. Comparison with available experimental data is made

  3. Fluid model of dc glow discharge with nonlocal ionization source term

    International Nuclear Information System (INIS)

    Rafatov, I R; Bogdanov, E A; Kudryavtsev, A A

    2012-01-01

    We developed and tested a simple hybrid model for a glow discharge, which incorporates nonlocal ionization by fast electrons into the fluid framework. Calculations have been performed for an argon gas. Comparison with the experimental data as well as with the hybrid (particle) and fluid modelling results demonstated good applicability of the proposed model.

  4. Period multiplication and chaotic phenomena in atmospheric dielectric-barrier glow discharges

    International Nuclear Information System (INIS)

    Wang, Y. H.; Zhang, Y. T.; Wang, D. Z.; Kong, M. G.

    2007-01-01

    In this letter, evidence of temporal plasma nonlinearity in which atmospheric dielectric-barrier discharges undergo period multiplication and chaos using a one-dimensional fluid model is reported. Under the conditions conducive for chaotic states, several frequency windows are identified in which period multiplication and secondary bifurcations are observed. Such time-domain nonlinearity is important for controlling instabilities in atmospheric glow discharges

  5. Formation and evolution of the glow-like dielectric barrier discharge at atmospheric pressure

    NARCIS (Netherlands)

    Starostin, S.A.; ElSabbagh, M.A.M.; Premkumar, P.A.; Vries, de H.W.; Paffen, R.M.J.; Creatore, M.; Sanden, van de M.C.M.

    2008-01-01

    Time resolved process of formation and evolution of the atmospheric pressure glow discharge was studied in the roll-to- roll plasma- enhanced chemical vapor deposition dielectric barrier discharge reactor operating in helium-free gas mixtures by means of fast ICCD imaging. It was observed that the

  6. Gas phase hydrogen peroxide production in atmospheric pressure glow discharges operating in He - H2O

    NARCIS (Netherlands)

    Vasko, C.A.; Veldhuizen, van E.M.; Bruggeman, P.J.

    2013-01-01

    The gas phase production of hydrogen peroxide (H2O2) in a RF atmospheric pressure glow discharge with helium and water vapour has been investigated as a function of the gas flow. It is shown that the production of H2O2 is through the recombination of two OH radicals in a three body collision and the

  7. Peculiarities of glow modes of argon atmospheric pressure radio-frequency capacitive discharge with isolated electrodes

    International Nuclear Information System (INIS)

    Bazhenov, V.Yu.; Tsiolko, V.V.; Piun, V.M.; Chaplinskiy, R.Yu.; Kuzmichev, A.I.

    2013-01-01

    Glow characteristics of capacitive radio frequency discharge with isolated electrodes in low-current α and highcurrent gamma modes are determined experimentally. It is shown that transition from α mode to gamma mode occurs through a phase of coexistence of both modes in different parts of the discharge gap.

  8. Surface analysis of uranyl fluoride layers with a glow discharge lamp

    International Nuclear Information System (INIS)

    Nel, J.T.; Stander, C.M.; Boehmer, R.G.

    1991-01-01

    Surface analysis with a Grimm-type glow discharge lamp was used to analyse uranyl fluoride layers that had formed on a nickel substrate after exposure to UF 6 . Narrow-band optical filters were used to isolate the intensities of three fluorine emission lines. An in-depth profile of layer composition was obtained. (author)

  9. Accounting protesting and warm glow bidding in Contingent Valuation surveys considering the management of environmental goods

    DEFF Research Database (Denmark)

    Grammatikopoulou, Ioanna; Olsen, Søren Bøye

    2013-01-01

    Based on a Contingent Valuation survey aiming to reveal the willingness to pay (WTP) for conservation of a wetland area in Greece, we show how protest and warm glow motives can be taken into account when modeling WTP. In a sample of more than 300 respondents, we find that 54% of the positive bids...

  10. Anode pattern formation in atmospheric pressure air glow discharges with water anode

    NARCIS (Netherlands)

    Verreycken, T.; Bruggeman, P.J.; Leys, C.

    2009-01-01

    Pattern formation in the anode layer at a water electrode in atmospheric pressure glow discharges in air is studied. With increasing current a sequence of different anode spot structures occurs from a constricted homogeneous spot in the case of small currents to a pattern consisting of small

  11. Simulation Study of an Extended Density DC Glow Toroidal Plasma Source

    International Nuclear Information System (INIS)

    Granda-Gutierrez, E. E.; Piedad-Beneitez, A. de la; Lopez-Callejas, R.; Godoy-Cabrera, O. G.; Benitez-Read, J. S.; Pacheco-Sotelo, J. O.; Pena-Eguiluz, R.; Mercado-Cabrera, A.; Valencia A, R.; Barocio, S. R.

    2006-01-01

    Conventional wisdom assigns the DC glow discharge regime to plasma currents below ∼500 mA values, beyond which the discharge falls into the anomalous glow and the turbulent arc regimes. However, we have found evidence that, during toroidal discharges, this barrier can be ostensibly extended up to 800 mA. Thus, a computer simulation has been applied to the evolution of the main electrical characteristics of such a glow discharge plasma in a toroidal vessel in order to design and construct a respective voltage/current controlled source. This should be able to generate a DC plasma in the glow regime with which currents in the range 10-3-100 A can be experimented and 109-1010 cm-3 plasma densities can be achieved to PIII optimization purposes. The plasma is modelled as a voltage-controlled current source able to be turned on whenever the breakdown voltage is reached across the gap between the anode and the vessel wall. The simulation outcome fits well our experimental measurements showing that the plasma current obeys power laws that are dependent on the power current and other control variables such as the gas pressure

  12. I'm sexy and I glow it: female ornamentation in a nocturnal capital breeder.

    Science.gov (United States)

    Hopkins, Juhani; Baudry, Gautier; Candolin, Ulrika; Kaitala, Arja

    2015-10-01

    In many species, males rely on sexual ornaments to attract females. Females, by contrast, rarely produce ornaments. The glow-worm (Lampyris noctiluca) is an exception where wingless females glow to attract males that fly in search of females. However, little is known about the factors that promote the evolution of female ornaments in a sexual selection context. Here, we investigated if the female ornament of the glow-worm is a signal of fecundity used in male mate choice. In support of this, we found brightness to correlate with female fecundity, and males to prefer brighter dummy females. Thus, the glow emitted by females is a reliable sexual signal of female fecundity. It is likely that male preference for the fecundity-indicating ornament has evolved because of large variation among females in fecundity, and because nocturnal males cannot directly assess female size and fecundity. These results indicate that female ornamentation may evolve in capital breeders (i.e. those in which stored resources are invested in reproduction) when females vary significantly in fecundity and this variation cannot be assessed directly by males. © 2015 The Author(s).

  13. Modeling the energy deposition in the Aurora KrF laser amplifier chain

    International Nuclear Information System (INIS)

    Comly, J.C.; Czuchlewski, S.J.; Greene, D.P.; Hanson, D.E.; Krohn, B.J.; McCown, A.W.

    1988-01-01

    Monte Carlo calculations model the energy depositions by highly energetic electron beams into the cavities of the four KrF laser amplifiers in the Aurora chain. Deposited energy density distributions are presented and studied as functions of e-beam energy and gas pressure. Results are useful for analyzing small signal gain (SSG) measurements and optimizing deposition in future experiments. 7 refs., 7 figs., 1 tab

  14. Observation of the pulsating aurora by S-520-12 rocket at Norway

    International Nuclear Information System (INIS)

    Tsuruda, K.; Hayakawa, H.; Machida, S.; Mukai, T.; Morioka, A.; Nagano, I.; Miyaoka, H.

    1991-01-01

    Particle, field an wave observations in a pulsating aurora have been carried out using the sounding rocket S-520-12, at northern polar region, Norway, on February 26, 1990. The initial analysis has disclosed two new findings, (i) precipitating low energy electrons associated with the auroral patch region, which suggests the secondary local acceleration of the auroral particles, (ii) pulsating LF wave component that is generated by periodically precipitating energetic electrons above the auroral ionosphere. (author)

  15. Pulsating aurora and cosmic noise absorption associated with growth-phase arcs

    Directory of Open Access Journals (Sweden)

    D. McKay

    2018-01-01

    Full Text Available The initial stage of a magnetospheric substorm is the growth phase, which typically lasts 1–2 h. During the growth phase, an equatorward moving, east–west extended, optical auroral arc is observed. This is called a growth-phase arc. This work aims to characterize the optical emission and riometer absorption signatures associated with growth-phase arcs of isolated substorms. This is done using simultaneous all-sky camera and imaging riometer observations. The optical and riometric observations allow determination of the location of the precipitation within growth-phase arcs of low- (< 10  keV and high- (>  10 keV energy electrons, respectively. The observations indicate that growth-phase arcs have the following characteristics: 1. The peak of the cosmic noise absorption (CNA arc is equatorward of the optical emission arc. This CNA is contained within the region of diffuse aurora on the equatorward side.2. Optical pulsating aurora are seen in the border region between the diffuse emission region on the equatorward side and the bright growth-phase arc on the poleward side. CNA is detected in the same region. 3. There is no evidence of pulsations in the CNA. 4. Once the equatorward drift starts, it proceeds at constant speed, with uniform separation between the growth-phase arc and CNA of 40 ± 10 km. Optical pulsating aurora are known to be prominent in the post-onset phase of a substorm. The fact that pulsations are also seen in a fairly localized region during the growth phase shows that the substorm expansion-phase dynamics are not required to closely precede the pulsating aurora.

  16. Status of the Aurora laser system: Angular-multiplexed multikilojoule krypton fluoride prototype for inertial fusion

    International Nuclear Information System (INIS)

    Rosocha, L.A.; Goldstone, P.D.; Kristal, R.

    1986-01-01

    In this presentation, the authors report on the present status of the Aurora system including: The operation of the final stage 1-X 1-m laser at the 10-kJ level; the generation of 5-ns pulses by the front end; integration of the front end, multiplexer, amplifiers, and the extraction of long-pulse energy from the amplifier chain. Progress on the design and construction of the demultiplexer are also reported

  17. Shock aurora: Field-aligned discrete structures moving along the dawnside oval

    Science.gov (United States)

    Zhou, Xiaoyan; Haerendel, Gerhard; Moen, Jøran I.; Trondsen, Espen; Clausen, Lasse; Strangeway, Robert J.; Lybekk, Bjørn; Lorentzen, Dag A.

    2017-03-01

    Generated by interplanetary shocks or solar wind pressure pulses, shock aurora has transient, global, and dynamic significances and provides a direct manifestation of the solar wind-magnetosphere-ionosphere interaction. As a part of a series of studies of the shock aurora, this paper focuses on the interaction at the morning magnetopause and its auroral manifestation at 06 magnetic local time, where the velocity and magnetic field shears dominate the interaction. Flow shears can generate wave-like structures inside a viscous boundary layer or even larger-scale vortices. These structures couple to the ionosphere via quasi-static field-aligned currents or via kinetic Alfvén waves. Potential drops along field-aligned filaments may be generated accelerating electrons to form auroral manifestations of the structures. A shock aurora event at dawnside is used to test this scenario. The findings include moving auroral streaks/rays that have a vertical profile from red (at 250 km altitude) to purple (at 100 km). The streaks moved antisunward along the poleward boundary of the oval at an ionospheric speed of 3 km s-1. It was mapped to the magnetopause flank at 133 km s-1, which was consistent with the observed speed of the magnetopause surface waves generated by the Kelvin-Helmholtz instability. The calculated field-aligned potential drop using Haerendel's analytic model was 5 kV that reasonably explained the observations. The results support the above scenario and reveal that magnetic and velocity shears at the flanks of the magnetospause may be the main cause of the fast moving shock aurora streaks.

  18. Magnetospheric source region of discrete auroras inferred from their relationship with isotropy boundaries of energetic particles

    Directory of Open Access Journals (Sweden)

    A. G. Yahnin

    1997-08-01

    Full Text Available According to observations, the discrete auroral arcs can sometimes be found, either deep inside the auroral oval or at the poleward border of the wide (so-called double auroral oval, which map to very different regions of the magnetotail. To find common physical conditions for the auroral-arc generation in these magnetotail regions, we study the spatial relationship between the diffuse and discrete auroras and the isotropic boundaries (IBs of the precipitating energetic particles which can be used to characterise locally the equatorial magnetic field in the tail. From comparison of ground observation of auroral forms with meridional profiles of particle flux measured simultaneously by the low-altitude NOAA satellites above the ground observation region, we found that (1 discrete auroral arcs are always situated polewards from (or very close to the IB of >30-keV electrons, whereas (2 the IB of the >30-keV protons is often seen inside the diffuse aurora. These relationships hold true for both quiet and active (substorm conditions in the premidnight-nightside (18-01-h MLT sector considered. In some events the auroral arcs occupy a wide latitudinal range. The most equatorial of these arcs was found at the poleward edge of the diffuse auroras (but anyway in the vicinity of the electron IB, the most poleward arcs were simultaneously observed on the closed field lines near the polar-cap boundary. These observations disagree with the notion that the discrete aurora originate exclusively in the near-Earth portion of plasma sheet or exclusively on the PSBL field lines. Result (1 may imply a fundamental feature of auroral-arc formation: they originate in the current-sheet regions having very curved and tailward-stretched magnetic field lines.

  19. Bora and Aurora-A continue to activate Plk1 in mitosis

    Czech Academy of Sciences Publication Activity Database

    Bruinsma, W.; Macůrek, Libor; Freire, R.; Lindqvist, A.; Medema, R.H.

    2014-01-01

    Roč. 127, č. 4 (2014), s. 801-811 ISSN 0021-9533 R&D Projects: GA ČR GA13-18392S Grant - others:Ministerio de Economía y Competitividad(ES) SAF2010-22357; CONSOLIDER-Ingenio(NL) CDS2007-0015 Keywords : Aurora-A * Bora * Mitosis * Plk1 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.432, year: 2014

  20. Ionospheric Electron Heating Associated With Pulsating Auroras: Joint Optical and PFISR Observations

    Science.gov (United States)

    Liang, Jun; Donovan, E.; Reimer, A.; Hampton, D.; Zou, S.; Varney, R.

    2018-05-01

    In a recent study, Liang et al. (2017, https://doi.org/10.1002/2017JA024127) repeatedly identified strong electron temperature (Te) enhancements when Swarm satellites traversed pulsating auroral patches. In this study, we use joint optical and Poker Flat Incoherent Scatter Radar (PFISR) observations to further investigate the F region plasma signatures related to pulsating auroras. On 19 March 2015 night, which contained multiple intervals of pulsating auroral activities, we identify a statistical trend, albeit not a one-to-one correspondence, of strong Te enhancements ( 500-1000 K) in the upper F region ionosphere during the passages of pulsating auroras over PFISR. On the other hand, there is no discernible and repeatable density enhancement in the upper F region during pulsating auroral intervals. Collocated optical and NOAA satellite observations suggest that the pulsating auroras are composed of energetic electron precipitation with characteristic energy >10 keV, which is inefficient in electron heating in the upper F region. Based upon PFISR observations and simulations from Liang et al. (2017) model, we propose that thermal conduction from the topside ionosphere, which is heated by precipitating low-energy electrons, offers the most likely explanation for the observed electron heating in the upper F region associated with pulsating auroras. Such a heating mechanism is similar to that underlying the "stable auroral red arcs" in the subauroral ionosphere. Our proposal conforms to the notion on the coexistence of an enhanced cold plasma population and the energetic electron precipitation, in magnetospheric flux tubes threading the pulsating auroral patch. In addition, we find a trend of enhanced ion upflows during pulsating auroral intervals.

  1. Possible Cause of Extremely Bright Aurora Witnessed in East Asia on 17 September 1770

    Science.gov (United States)

    Ebihara, Yusuke; Hayakawa, Hisashi; Iwahashi, Kiyomi; Tamazawa, Harufumi; Kawamura, Akito Davis; Isobe, Hiroaki

    2017-10-01

    Extremely bright aurora was witnessed in East Asia on 17 September 1770, according to historical documents. The aurora was described as "as bright as a night with full moon" at magnetic latitude of 25°. The aurora was dominated by red color extending from near the horizon up beyond the polar star (corresponding to elevation angle of 35°). We performed a two-stream electron transport code to calculate the volume emission rates at 557.7 nm (OI) and 630.0 nm (OI). Two types of distribution of precipitating electrons were assumed. The first one is based on the unusually intense electron flux measured by the DMSP satellite in the March 1989 storm. The distribution consists of hot (peaking at 3 keV) and cold (peaking at 71 eV) components. The second one is the same as the first one, but the hot component is removed. We call this high-intensity low-energy electrons (HILEEs). The first spectrum results in an auroral display with a bright, lower green border. The second one results in red-dominated aurora extending up to the elevation angle of 35° when the equatorward boundary of the electron precipitation is located at 32° invariant latitude. The poleward boundary of the precipitation would be 42° invariant latitude or greater to explain the auroral display extending from near the horizon. The origin of the HILEEs is probably the plasma sheet or the plasmasphere that is transported earthward to L 1.39 due to enhanced magnetospheric convection. Local heating or acceleration is also plausible.

  2. Integrating Felting in Elementary Science Classrooms to Facilitate Understanding of the Polar Auroras

    Directory of Open Access Journals (Sweden)

    Brandy Terrill

    2017-10-01

    Full Text Available The Next Generation Science Standards (NGSS emphasize conceptual science instruction that draws on students’ ability to make observations, explain natural phenomena, and examine concept relationships. This paper explores integrating the arts, in the form of felting, in elementary science classrooms as a way for students to model and demonstrate understanding of the complex scientific processes that cause the polar auroras. The steps for creating felting, and using the felting artwork students create for assessing science learning, are described.

  3. GATEWAY Report Brief: OLED Lighting in the Offices of Aurora Lighting Design, Inc.

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2016-05-31

    Summary of a GATEWAY report evaluation at the offices of Aurora Lighting Design, Inc., in Grayslake, IL, where the GATEWAY program conducted its first investigation involving OLED lighting. The project experienced several challenges, but also highlighted a number of promising attributes – which indicate that with continued improvements in efficacy, longevity, size, and flexibility, OLEDs could provide a new tool for creative and effective lighting.

  4. Aurora Research: Earth/Space Data Fusion Powered by GIS and Python

    Science.gov (United States)

    Kalb, V. L.; Collado-Vega, Y. M.; MacDonald, E.; Kosar, B.

    2017-12-01

    The Aurora Borealis and Australis Borealis are visually spectacular, but are also an indicator of Sun-magnetosphere-ionosphere energy transfer during geomagnetic storms. The Saint Patrick's Day Storm of 2015 is a stellar example of this, and is the focus of our study that utilizes the Geographical Information Services of ArcGIS to bring together diverse and cross disciplinary data for analysis. This research leverages data from a polar-orbiting Earth science sensor band that is exquisitely sensitive to visible light, namely the Day/Night Band (DNB) of the VIIRS instrument onboard the Suomi NPP satellite. This Sun-synchronous data source can provide high temporal and spatial resolution observations of the aurorae, which is not possible with current space science instruments. This data can be compared with auroral model data, solar wind measurements, and citizen science data of aurora observations and tweets. While the proposed data sources are diverse in type and format, their common attribute is location. This is exploited by bringing all the data into ArcGIS for mapping and analysis. The Python programming language is used extensively to automate the data preprocessing, group the DNB and citizen science observations to temporal windows associated with an auroral model timestep, and print the data to a pdf mapbook for sharing with team members. There are several goals for this study: compare the auroral model predictions with DNB data, look for fine-grained structure of the aurora in the DNB data, compare citizen science data with DNB values, and correlate DNB intensity with solar wind data. This study demonstrates the benefits of using a GIS platform to bring together data that is diverse in type and format for scientific exploration, and shows how Python can be used to scale up to large datasets.

  5. A compact SR light source for x-ray lithography 'AURORA'

    International Nuclear Information System (INIS)

    Toba, Y.

    1990-01-01

    A compact synchrotron radiation (SR) light source called AURORA has been developed for industrial use. It is specially designed for X-ray lithography. AURORA consists of a storage ring, injector microtron and SR light beam lines. The storage ring is a superconducting single magnet machine, designed to accelerate a 150 MeV electron beam to 650 MeV and to store as high as 300 mA current. The injector is a racetrack microtron (RTM) producing a pulsed 150 MeV beam. As many as 16 SR light beam channels are available for AURORA. Prototypes of the storage ring and RTM are constructed, and beam commissioning is performed. A hundred and fifty MeV electron beam of a pulsed current 10 μA from the RTM is successfully injected to the ring and accelerated to 600 MeV and 10 mA current stored with a lifetime of more than 20 hours. The half-integer method investigated is shown to work well with the injection efficiency being found to be very high. Improvement of the design is now under way. (N.K.)

  6. Observation of O+ (4P-4D0 lines in electron aurora over Svalbard

    Directory of Open Access Journals (Sweden)

    K. Throp

    2004-09-01

    Full Text Available This work reports on observations of O+ lines in aurora over Svalbard, Norway. The Spectrographic Imaging Facility measures auroral spectra in three wavelength intervals (Hβ, N+2 1N(0,2 and N+2 1N(1,3. The oxygen ion multiplet (4639-4696Å is blended with the band. It is found that in electron aurora, the brightness of this multiplet, is on average, about 0.1 of the total brightness. A joint optical and incoherent scatter radar study of an electron aurora event shows that the ratio is enhanced when the ionisation in the upper E-layer (140-190km is significant with respect to the E-layer peak below 130km. Rayed arcs were observed on one such occasion, whereas on other occasions the auroral intensity was below the threshold of the imager. A one-dimensional electron transport model is used to estimate the cross section for production of the multiplet in electron collisions, yielding 0.18x10-18cm2.

  7. Morphology and dynamics of aurora at fine scale: first results from the ASK instrument

    Directory of Open Access Journals (Sweden)

    H. Dahlgren

    2008-05-01

    Full Text Available The ASK instrument (Auroral Structure and Kinetics is a narrow field auroral imager, providing simultaneous images of aurora in three different spectral bands at multiple frames per second resolution. The three emission species studied are O2+ (5620 Å, O+ (7319 Å and O (7774 Å. ASK was installed and operated for the first time in an observational campaign on Svalbard, from December 2005 to March 2006. The measurements were supported by data from the Spectrographic Imaging Facility (SIF. The relation between the morphology and dynamics of the visible aurora and its spectral characteristics is studied for selected events from this period. In these events it is found that dynamic aurora is coupled to high energy electron precipitation. By studying the O2+/O intensity ratio we find that some auroral filaments are caused by higher energy precipitation within regions of lower energy precipitation, whereas other filaments are the result of a higher particle flux compared to the surroundings.

  8. Phosphorylation of CPAP by Aurora-A Maintains Spindle Pole Integrity during Mitosis.

    Science.gov (United States)

    Chou, En-Ju; Hung, Liang-Yi; Tang, Chieh-Ju C; Hsu, Wen-Bin; Wu, Hsin-Yi; Liao, Pao-Chi; Tang, Tang K

    2016-03-29

    CPAP is required for centriole elongation during S/G2 phase, but the role of CPAP in mitosis is incompletely understood. Here, we show that CPAP maintains spindle pole integrity through its phosphorylation by Aurora-A during mitosis. Depletion of CPAP induced a prolonged delay in mitosis, pericentriolar material (PCM) dispersion, and multiple mitotic abnormalities. Further studies demonstrated that CPAP directly interacts with and is phosphorylated by Aurora-A at serine 467 during mitosis. Interestingly, the dispersal of the PCM was effectively rescued by ectopic expression of wild-type CPAP or a phospho-mimic CPAP-S467D mutant, but not a non-phosphorylated CPAP-S467A mutant. Finally, we found that CPAP-S467D has a low affinity for microtubule binding but a high affinity for PCM proteins. Together, our results support a model wherein CPAP is required for proper mitotic progression, and phosphorylation of CPAP by Aurora-A is essential for maintaining spindle pole integrity. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  9. The instantaneous relationship between polar cap and oval auroras at times of northward interplanetary magnetic field

    International Nuclear Information System (INIS)

    Murphree, J.S.; Anger, C.D.; Cogger, L.L.

    1982-01-01

    Optical images of the polar cap region at both 5577 and 3914 A obtained from 1400 km above the earth have been used to study the relationship between polar cap and oval aurora during periods when the interplanetary magnetic field is strongly northward, i.e., B > 3.5 nT. When this rather rare condition occurs, distinction between the two types of aurora is no longer as clear as depicted on the basis of statistical definitions of the auroral oval. Diffuse, weak emission can fill in the region between the auroral oval and discrete auroral features in the polar cap. The polar cap discrete features can appear very similar to auroral oval arcs in intensity, intensity ratio, and structure. Even more striking are the situations where discrete polar cap features merge with oval auroras. From this study it is concluded that under conditions of large positive B the region of closed magnetic field lines can expand poleward to occupy much of the high latitude region

  10. Phosphorylation of CPAP by Aurora-A Maintains Spindle Pole Integrity during Mitosis

    Directory of Open Access Journals (Sweden)

    En-Ju Chou

    2016-03-01

    Full Text Available CPAP is required for centriole elongation during S/G2 phase, but the role of CPAP in mitosis is incompletely understood. Here, we show that CPAP maintains spindle pole integrity through its phosphorylation by Aurora-A during mitosis. Depletion of CPAP induced a prolonged delay in mitosis, pericentriolar material (PCM dispersion, and multiple mitotic abnormalities. Further studies demonstrated that CPAP directly interacts with and is phosphorylated by Aurora-A at serine 467 during mitosis. Interestingly, the dispersal of the PCM was effectively rescued by ectopic expression of wild-type CPAP or a phospho-mimic CPAP-S467D mutant, but not a non-phosphorylated CPAP-S467A mutant. Finally, we found that CPAP-S467D has a low affinity for microtubule binding but a high affinity for PCM proteins. Together, our results support a model wherein CPAP is required for proper mitotic progression, and phosphorylation of CPAP by Aurora-A is essential for maintaining spindle pole integrity.

  11. A 230 ka record of glacial and interglacial events from Aurora Cave, Fiordland, New Zealand

    International Nuclear Information System (INIS)

    Williams, P.W.

    1996-01-01

    Caves overrun by glaciers are known to accumulate dateable evidence of past glacial and interglacial events. Results are reported from an investigation of Aurora Cave on the slopes above Lake Te Anau in Fiordland. The cave commenced to form before c. 230 ka B.P. Sequences of glaciofluvial sediments interbedded with speleothems are evidence of the number and timing of glacial advances and the status of intervals between them. Twenty-six uranium series dates on speleothems underpin a chronology of seven glacial advances in the last 230 ka, with the peak of the late Otira glaciation, Aurora 3 advance, at c. 19 ka B.P. With five advances in the Otiran, the last glaciation is more complex than previously recognised. Comparison of the record with that recorded offshore from DSDP Site 594 reveals little matching, but the correspondence of the Aurora sequence with that interpreted from other onshore deposits is more convincing. Glacial deposits on slopes above the cave for a further 660 m may be evidence of the 'missing' glacial events of the mid-early Pleistocene. (author). 44 refs., 12 figs., 5 tabs

  12. Strong Solar Control of Infrared Aurora on Jupiter: Correlation Since the Last Solar Maximum

    Science.gov (United States)

    Kostiuk, T.; Livengood, T. A.; Hewagama, T.

    2009-01-01

    Polar aurorae in Jupiter's atmosphere radiate throughout the electromagnetic spectrum from X ray through mid-infrared (mid-IR, 5 - 20 micron wavelength). Voyager IRIS data and ground-based spectroscopic measurements of Jupiter's northern mid-IR aurora, acquired since 1982, reveal a correlation between auroral brightness and solar activity that has not been observed in Jovian aurora at other wavelengths. Over nearly three solar cycles, Jupiter auroral ethane emission brightness and solar 10.7 cm radio flux and sunspot number are positively correlated with high confidence. Ethane line emission intensity varies over tenfold between low and high solar activity periods. Detailed measurements have been made using the GSFC HIPWAC spectrometer at the NASA IRTF since the last solar maximum, following the mid-IR emission through the declining phase toward solar minimum. An even more convincing correlation with solar activity is evident in these data. Current analyses of these results will be described, including planned measurements on polar ethane line emission scheduled through the rise of the next solar maximum beginning in 2009, with a steep gradient to a maximum in 2012. This work is relevant to the Juno mission and to the development of the Europa Jupiter System Mission. Results of observations at the Infrared Telescope Facility (IRTF) operated by the University of Hawaii under Cooperative Agreement no. NCC5-538 with the National Aeronautics and Space Administration, Science Mission Directorate, Planetary Astronomy Program. This work was supported by the NASA Planetary Astronomy Program.

  13. Regulation

    International Nuclear Information System (INIS)

    Ballereau, P.

    1999-01-01

    The different regulations relative to nuclear energy since the first of January 1999 are given here. Two points deserve to be noticed: the decree of the third august 1999 authorizing the national Agency for the radioactive waste management to install and exploit on the commune of Bures (Meuse) an underground laboratory destined to study the deep geological formations where could be stored the radioactive waste. The second point is about the uranium residues and the waste notion. The judgment of the administrative tribunal of Limoges ( 9. july 1998) forbidding the exploitation of a storage installation of depleted uranium considered as final waste and qualifying it as an industrial waste storage facility has been annulled bu the Court of Appeal. It stipulated that, according to the law number 75663 of the 15. july 1965, no criteria below can be applied to depleted uranium: production residue (possibility of an ulterior enrichment), abandonment of a personal property or simple intention to do it ( future use aimed in the authorization request made in the Prefecture). This judgment has devoted the primacy of the waste notion on this one of final waste. (N.C.)

  14. A phase I/II trial of AT9283, a selective inhibitor of aurora kinase in children with relapsed or refractory acute leukemia: challenges to run early phase clinical trials for children with leukemia.

    Science.gov (United States)

    Vormoor, B; Veal, G J; Griffin, M J; Boddy, A V; Irving, J; Minto, L; Case, M; Banerji, U; Swales, K E; Tall, J R; Moore, A S; Toguchi, M; Acton, G; Dyer, K; Schwab, C; Harrison, C J; Grainger, J D; Lancaster, D; Kearns, P; Hargrave, D; Vormoor, J

    2017-06-01

    Aurora kinases regulate mitosis and are commonly overexpressed in leukemia. This phase I/IIa study of AT9283, a multikinase inhibitor, was designed to identify maximal tolerated doses, safety, pharmacokinetics, and pharmacodynamic activity in children with relapsed/refractory acute leukemia. The trial suffered from poor recruitment and terminated early, therefore failing to identify its primary endpoints. AT9283 caused tolerable toxicity, but failed to show clinical responses. Future trials should be based on robust preclinical data that provide an indication of which patients may benefit from the experimental agent, and recruitment should be improved through international collaborations and early combination with established treatment strategies. © 2016 Wiley Periodicals, Inc.

  15. First Joint Observations of Radio Aurora by the VHF and HF Radars of the ISTP SB RAS

    Science.gov (United States)

    Berngardt, O. I.; Lebedev, V. P.; Kutelev, K. A.; Kushnarev, D. S.; Grkovich, K. V.

    2018-01-01

    Two modern radars for diagnosis of the ionosphere by the radio-wave backscattering method, namely, the Irkutsk incoherent scatter radar at VHF (IISR, 154-162 MHz) and the Ekaterinburg coherent radar at HF (EKB, 8-20 MHz) are operated at the Institute of Solar-Terrestrial Physics, Siberian Branch of the Russian Academy of Sciences (ISTP SB RAS). The paper analyzes the results of joint observations of strong scattering (radio aurora) on June 8, 2015. To determine the geographical position of the radio aurora, we developed original methods that take into account both the features of the radio-wave propagation and the features of the radar antenna systems. It is shown that there are areas where the spatial position of the HF and VHF radio aurora can coincide. This permits using the radars as a single complex for diagnosis of the characteristics of small-scale high-latitude irregularities in the ionospheric E and F layers. A comparative analysis of the characteristics and temporal dynamics of the radio-aurora region in the HF and VHF ranges is performed. Using the DMSP satellite data, it has been shown that the radio aurora dynamics during this experiment with the EKB radar can be related with the spatial dynamics of the localized area with high electric field, which moves from high to equatorial latitudes. It is found that due to the broader field of view, radio aurora at the HF radar was stably observed 6-12 min earlier than at the VHF radar. This permits using the EKB radar data for prediction of the radio-aurora detection by the IISR radar.

  16. Correlation between TL and OSL signals in KMgF3:Ce3+: Bleaching study of individual glow-peaks

    International Nuclear Information System (INIS)

    Dallas, G.I.; Polymeris, G.S.; Afouxenidis, D.; Tsirliganis, N.C.; Tsagas, N.F.; Kitis, G.

    2010-01-01

    KMgF 3 :Ce 3+ is an ultra sensitive Thermoluminescence (TL) material with a complex TL and OSL glow-curve structure. The aim of the present work is to attempt a one-to-one correspondence between specific TL glow-peaks and OSL components in KMgF 3 :Ce 3+ . The correlation study involves the deconvolution of the TL curves and the estimation of the bleaching decay constants for individual glow-peaks followed by the deconvolution of the LM-OSL curve using the estimated decay constants. It was found that the bleaching of each individual glow-peak takes place in three different rates; namely in a fast, medium and slow rate.

  17. R. B. Cunninghame Graham’s “Aurora La Cujiñi” (1898 : An Exploration / Aurora La Cujiñi” (1898 de R. B. Cunninghame Graham - Una indagación

    Directory of Open Access Journals (Sweden)

    John C. Mc Intyre

    2011-06-01

    Full Text Available Abstract: In Aurora La Cujiñi-A realistic sketch in Seville, published by the Scottish writer R. B. Cunninghame Graham in 1898, the frontispiece showed the sepia image of a female flamenco dancer. What might ‘La Cujiñi’ mean? Charles Davillier and Gustave Doré in 1862-63 note the existence of a Sevillan dancer with this name. In 2011 the present writer was gifted an old lithograph, in colour, published in Seville ‘c. 1850’ and entitled ‘Aurora La Cujiñí’ - with ñ and í. The two images are supplied. ‘Aurora La Cujiñi’ really existed. Graham’s sketch has five phases: Seville; the bullfight; the crowd’s return to town; a low-quality flamenco show; and the highly stirring performance by an initially anonymous female dancer - the dead Aurora brought back to life. Graham emphasises the Seville blend of blood and sensuality in a realist style also capable of mockery and criticism. Graham’s writing includes a good variety of well-controlled Spanish vocabulary, his empathy with horses and a deep nostalgia for times past. W. H. Hudson, writer and friend of Graham, in 1894 recommended that Graham should read the Argentine sketches published by Alfred Ébélot in 1890. In Aurora La Cujiñi Graham in 1898 is beginning to show mastery of the literary sketch. Question: Might Lorca have read Aurora La Cujiñi before drafting “Teoría y juego del duende”? Resumen: En Aurora La Cujiñi-A realistic sketch in Seville (1898 del escritor escocés R. B. Cunninghame Graham, el frontispicio llevaba la imagen en sepia de una bailadora de flamenco. ¿Qué podría significar ‘La Cujiñi’? Charles Davillier y Gustave Doré en 1862-1863 apuntan la existencia de una bailaora sevillana con este nombre. En 2011 al que esto escribe le regalaron una litografía antigua, en color, publicada en Sevilla ‘hacia 1850’ e intitulada ‘Aurora la Cujiñí’ - con ñ y con í. Se incluyen las dos imágenes. ‘Aurora La Cujiñi’ realmente

  18. Analysis of nickel-base alloys by Grimm-type glow discharge emission and x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Ferreira, N.P.; Strauss, J.A.; Van Maarseveen, I.; Ivanfy, A.B.

    1985-01-01

    Nickel-base alloys can be analysed as satisfactorily as steels by XRF as well as by the Grimm-type source, in spite of problems caused by element combinations, spectral line overlap and the influence of the structure and heat conduction properties on sputtering in the glow discharge source. This extended abstract briefly discusses the use of Grimm-type glow discharge emission and XRF as techniques for the analysis of nickel-base alloys

  19. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    OpenAIRE

    Pai , David ,; Lacoste , Deanna ,; Laux , C.

    2010-01-01

    International audience; In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determine...

  20. Anticipated Guilt for Not Helping and Anticipated Warm Glow for Helping Are Differently Impacted by Personal Responsibility to Help

    Science.gov (United States)

    Erlandsson, Arvid; Jungstrand, Amanda Å.; Västfjäll, Daniel

    2016-01-01

    One important motivation for people behaving prosocially is that they want to avoid negative and obtain positive emotions. In the prosocial behavior literature however, the motivations to avoid negative emotions (e.g., guilt) and to approach positive emotions (e.g., warm glow) are rarely separated, and sometimes even aggregated into a single mood-management construct. The aim of this study was to investigate whether anticipated guilt if not helping and anticipated warm glow if helping are influenced similarly or differently when varying situational factors related to personal responsibility to help. Helping scenarios were created and pilot tests established that each helping scenario could be formulated both in a high-responsibility version and in a low-responsibility version. In Study 1 participants read high-responsibility and low-responsibility helping scenarios, and rated either their anticipated guilt if not helping or their anticipated warm glow if helping (i.e., separate evaluation). Study 2 was similar but here participants rated both their anticipated guilt if not helping and their anticipated warm glow if helping (i.e., joint evaluation). Anticipated guilt was clearly higher in the high-responsibility versions, but anticipated warm glow was unaffected (in Studies 1a and 1b), or even higher in the low-responsibility versions (Study 2). In Studies 3 (where anticipated guilt and warm glow were evaluated separately) and 4 (where they were evaluated jointly), personal responsibility to help was manipulated within-subjects. Anticipated guilt was again constantly higher in the high-responsibility versions but for many types of responsibility-manipulations, anticipated warm glow was higher in the low-responsibility versions. The results suggest that we anticipate guilt if not fulfilling our responsibility but that we anticipate warm glow primarily when doing over and beyond our responsibility. We argue that future studies investigating motivations for helping

  1. A study on the equivalent electric circuit simulation model of DBD streamer and glow alternate discharge

    International Nuclear Information System (INIS)

    Yao, J; Zhang, Z T; Xu, S J; Yu, Q X; Yu, Z; Zhao, J S

    2013-01-01

    This paper presents a dynamic simulating model of the dielectric barrier discharge (DBD), structured as an equivalent electric circuit of the streamer and glow discharge generated alternately in DBD. The main parameters of DBD have been established by means of analysing the structural characteristics of a single discharge cell. An electrical comprehensive Simulink /MATLAB model was developed in order to reveal the interaction of the adjacent two discharge cell. A series of simulations was carried out in order to estimate the key structural parameters that affect the alternate streamer and glow discharge mode. The comparison results of experimental and simulate indicate that there exists a close similarity of the current waveforms graphic. Therefore, we can grasp a deep understanding mechanism of the dielectric barrier discharge and optimize the plasma reactor.

  2. Influence of an electric probe on the anode layer of a glow discharge in nitrogen

    Science.gov (United States)

    Taran, M. D.; Dyatko, N. A.; Kochetov, I. V.; Napartovich, A. P.; Akishev, Yu S.

    2018-05-01

    A two-dimensional (2D) numerical model of a DC glow discharge in nitrogen is developed for the case when the electric probe is mounted in the discharge gap. Within this model, calculations are performed for the gas pressure of 50 Torr and discharge current densities of 22 and 90 mA cm‑2. A cylindrical probe 1 mm in diameter is located parallel to the anode at a distance of 5 or 10 mm. The probe potential is varied in a wide range relative to the floating potential. Numerical simulations predict the 2D plasma perturbation pattern induced by the electric probe and the influence of the probe on anode layer characteristics. In particular, conditions are determined under which a region with no glow forms in the anode layer.

  3. On the regime transitions during the formation of an atmospheric pressure dielectric barrier glow discharge

    International Nuclear Information System (INIS)

    Martens, T; Bogaerts, A; Brok, W J M; Van Dijk, J

    2009-01-01

    The atmospheric pressure dielectric barrier discharge in helium is a pulsed discharge in nature. If during the electrical current pulse a glow discharge is reached, then this pulse will last only a few microseconds in operating periods of sinusoidal voltage with lengths of about 10 to 100 μs. In this paper we demonstrate that right before a glow discharge is reached, the discharge very closely resembles the commonly assumed Townsend discharge structure, but actually contains some significant differing features and hence should not be considered as a Townsend discharge. In order to clarify this, we present calculation results of high time and space resolution of the pulse formation. The results indicate that indeed a maximum of ionization is formed at the anode, but that the level of ionization remains high and that the electric field at that time is significantly disturbed. Our results also show where this intermediate structure comes from. (fast track communication)

  4. Atomic iodine production in a gas flow by decomposing methyl iodide in a dc glow discharge

    International Nuclear Information System (INIS)

    Mikheyev, P A; Shepelenko, A A; Voronov, A I; Kupryaev, Nikolai V

    2002-01-01

    The production of atomic iodine for an oxygen - iodine laser is studied by decomposing methyl iodide in a dc glow discharge in a vortex gas flow. The concentration of iodine atoms in discharge products was measured from the atomic iodine absorption of the radiation of a single-frequency tunable diode laser at a wavelength of 1.315 μm. Atomic iodine concentrations sufficient for the operation of an oxygen - iodine laser were obtained. The concentration of atomic iodine amounted to 3.6 x 10 15 cm -3 for a pressure of the carrying argon gas of 15 Torr. The discharge stabilisation by a vortex gas flow allowed the glow discharge to be sustained in a strongly electronegative halogen-containing gas mixture for pressures up to 20 Torr. (active media)

  5. COATING AND MANDREL EFFECTS ON FABRICATION OF GLOW DISCHARGE POLYMER NIF SCALE INDIRECT DRIVE CAPSULES

    International Nuclear Information System (INIS)

    NIKROO, A.; PONTELANDOLFO, J.M.; CASTILLO, E.R.

    2002-01-01

    OAK A271 COATING AND MANDREL EFFECTS ON FABRICATION OF GLOW DISCHARGE POLYMER NIF SCALE INDIRECT DRIVE CAPSULES. Targets for the National Ignition Facility (NIF) need to be about 200 (micro)m thick and 2 mm in diameter. These dimensions are well beyond those currently fabricated on a routine basis. They have investigated fabrication of near NIF scale targets using the depolymerizable mandrel technique. Poly-alpha-methylstyrene (PAMS) mandrels, about 2 mm in diameter, of varying qualities were coated with as much as 125 (micro)m of glow discharge polymer (GDP). The surface finish of the final shells was examined using a variety of techniques. A clear dependence of the modal spectrum of final GDP shell on the quality of the initial PAMS mandrels was observed. isolated features were found to be the greatest cause for a shell not meeting the NIF standard

  6. Direct measurements of particle transport in dc glow discharge dusty plasmas

    International Nuclear Information System (INIS)

    Thomas, E. Jr.

    2001-01-01

    Many recent experiments in dc glow discharge plasmas have shown that clouds of dust particles can be suspended near the biased electrodes. Once formed, the dust clouds have well defined boundaries while particle motion within the clouds can be quite complex. Because the dust particles in the cloud can remain suspended in the plasma for tens of minutes, it implies that the particles have a low diffusive loss rate and follow closed trajectories within the cloud. In the experiments discussed in this paper, direct measurements of the dust particle velocities are made using particle image velocimetry (PIV) techniques. From the velocity measurements, a reconstruction of the three-dimensional transport of the dust particles is performed. A qualitative model is developed for the closed motion of the dust particles in a dc glow discharge dusty plasma. (orig.)

  7. On the feasibility of inversion methods based on models of urban sky glow

    International Nuclear Information System (INIS)

    Kolláth, Z.; Kránicz, B.

    2014-01-01

    Multi-wavelength imaging luminance photometry of sky glow provides a huge amount of information on light pollution. However, the understanding of the measured data involves the combination of different processes and data of radiation transfer, atmospheric physics and atmospheric constitution. State-of-the-art numerical radiation transfer models provide the possibility to define an inverse problem to obtain information on the emission intensity distribution of a city and perhaps the physical properties of the atmosphere. We provide numerical tests on the solvability and feasibility of such procedures. - Highlights: • A method of urban sky glow inversion is introduced based on Monte-Carlo calculations. • Imaging photometry can provide enough information for basic inversions. • The inversion technique can be used to construct maps of light pollution. • The inclusion of multiple scattering in the models plays an important role

  8. Electrostatic analyzer for electron and ion energy in glow discharge tube

    International Nuclear Information System (INIS)

    Bong Kil Yeon.

    1984-01-01

    The project, the construction and use of an electrostatic energy analyser (Faraday Cup) are described explaining physically its working mechanism. The analyser was used in a glow discharge tube with air and an air-argon mixture. A chapter with the theory of the glow discharge is included. The ion and electron temperatures, the plasma potential and the distribution function for ions and electrons were measured. The electron temperature and plasma potential were also measured using a Langmuir probe and the results show reasonable agreement with the results of the analyser. Good fits of the experimental electron and ion distribution functions were obtained with Maxwellian distributions centered values near the plasma potential. Finally, we discuss the performance of the analyser compared to Langmuir probes. (author) [pt

  9. Inner surface modification of a tube by magnetic glow-arc plasma source ion implantation

    International Nuclear Information System (INIS)

    Zhang Guling; Chinese Academy of Sciences, Beijing; Wang Jiuli; Feng Wenran; Chen Guangliang; Gu Weichao; Niu Erwu; Fan Songhua; Liu Chizi; Yang Size; Wu Xingfang

    2006-01-01

    A new method named the magnetic glow-arc plasma source ion implantation (MGA-PSII) is proposed for inner surface modification of tubes. In MGA-PSII, under the control of an axial magnetic field, which is generated by an electric coil around the tube sample, glow arc plasma moves spirally into the tube from its two ends. A negative voltage applied on the tube realized its inner surface implantation. Titanium nitride (TiN) films are prepared on the inner surface of a stainless steel tube in diameter 90 mm and length 600 mm. Hardness tests show that the hardness at the tube centre is up to 20 GPa. XRD, XPS and AES analyses demonstrate that good quality of TiN films can be achieved. (authors)

  10. Inner Surface Modification of a Tube by Magnetic Glow-Arc Plasma Source Ion Implantation

    Science.gov (United States)

    Zhang, Gu-Ling; Wang, Jiu-Li; Wu, Xing-Fang; Feng, Wen-Ran; Chen, Guang-Liang; Gu, Wei-Chao; Niu, Er-Wu; Fan, Song-Hua; Liu, Chi-Zi; Yang, Si-Ze

    2006-05-01

    A new method named the magnetic glow-arc plasma source ion implantation (MGA-PSII) is proposed for inner surface modification of tubes. In MGA-PSII, under the control of an axial magnetic field, which is generated by an electric coil around the tube sample, glow arc plasma moves spirally into the tube from its two ends. A negative voltage applied on the tube realized its inner surface implantation. Titanium nitride (TiN) films are prepared on the inner surface of a stainless steel tube in diameter 90 mm and length 600 mm. Hardness tests show that the hardness at the tube centre is up to 20 GPa. XRD, XPS and AES analyses demonstrate that good quality of TiN films can be achieved.

  11. Radiofrequency glow discharge time of flight mass spectrometry: pulsed vs. continuous mode

    International Nuclear Information System (INIS)

    Lobo, L.; Pereiro, R.; Sanz-Medel, A.; Bordel, N.; Tempez, A.; Chapon, P.; Hohl, M.; Michler, J.

    2009-01-01

    Full text: Glow discharge (GD) is a well established tool for the direct analysis of solids. The application field of the original direct current GD, restricted to conductive samples, has been extended by radiofrequency powered GDs that can be applied for conductive and non-conductive samples. Moreover, the introduction of pulsed GD has opened the possibility of applying higher instantaneous powers that can improve the atomization-ionization processes and therefore the sensitivity. Furthermore, pulsed-GD may enable temporal separation of discharge gas species from the sample ions. In this work the analytical performances of radiofrequency and pulsed radiofrequency glow discharges are evaluated by using a time of flight mass analyzer (TOFMS). (author)

  12. Nature and mechanism of blue glow of corundum crystals; new point of view

    International Nuclear Information System (INIS)

    Bessonova, T.S.; Zabara, A.S.

    1987-01-01

    The photoluminescence and radioluminescence spectra were investigated for corrundum crystals grown by Verneil method with following thermal treatment in different conditions: 1) annealing in oxygen 8p=10 5 Pa, T=1770 K, t=5x10 5 s); 2) vacuum annealing (p=10 -3 Pa, T=2220 K, t=10 5 s); 3) annelaing in high reducing atmosphere. Two kinds of luminescence processes is shown to exist at 415-420 nm. Blue glow with δ ∼ 55 nm (band halfwidth) is due to anion vacancies while glow with δ ∼ 100 nm is caused by titanium ions of valancy 4. mechanisms of mentioned kinds of luminescence and their distinctive features presented. New model of electron transitions in Al 2 O 3 -lattice including anion vacancie for different excitation means is proposed

  13. Analysis of the different zones of glow discharge of ethyl alcohol (C2H6O)

    International Nuclear Information System (INIS)

    Torres, C; Reyes, P G; Mulia, J; Castillo, F; Martínez, H

    2014-01-01

    The aim of this work is to explore the emission spectroscopy of ethyl alcohol in some regions, also is determine the result elements of the glow discharge, the spectrums were observed in a range of 200 at 1100 nm in the different zones inside of the tube at different distances of 20 and 30 cm. The elements are: in anode region C 6 H 5 (483.02 nm), CHO (519.56 nm) and H 2 (560.47 nm), in the positive column CO 2 + (315.52 y 337.00 nm), O + (357.48 nm), CH + (380.61 nm) and CO + (399.73 nm); in the cathode region we observed O + (391.19 nm), CHOCHO (428.00 nm), CO + (471.12 nm) and H 2 (656.52 nm). C 6 H 5 , CHO y H 2 species occurring in all regions analyzed varying the glow discharge emission intensity.

  14. Photo-preionization stabilized high-pressure glow-discharge lasers

    International Nuclear Information System (INIS)

    Von Bergmann, H.M.

    1980-07-01

    Simple nanosecond stabilization and pulsing techniques were developed to excite high-pressure gas-discharge lasers at high overvoltages and high specific power loadings. The techniques were applied to a variety of ultraviolet and visible laser systems employing fast transmission line pulsers and conventional LC generators. The stabilization procedures are evaluated and the parameters which control the geometry and uniformity of the high-pressure glow discharges are investigated. A detailed study of the formation, distribution and spectral characteristics of the fast surface corona discharges is provided. The stabilization and pulsing techniques were used for the corona and glow discharge excitation of high-pressure ultraviolet N 2 lasers. A detailed spectrally- and temporally-resolved study of the gain, fluorescence and energy extraction characteristics of the atmospheric pressure N 2 plasmas is provided

  15. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    Science.gov (United States)

    Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-05-01

    In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determined, with the notable result that there exists a minimum and maximum gap distance for its existence at a given ambient gas temperature. The minimum gap distance increases with decreasing gas temperature, whereas the maximum does not vary appreciably. To explain the experimental results, an analytical model is developed to explain the corona-to-glow (C-G) and glow-to-spark (G-S) transitions. The C-G transition is analyzed in terms of the avalanche-to-streamer transition and the breakdown field during the conduction phase following the establishment of a conducting channel across the discharge gap. The G-S transition is determined by the thermal ionization instability, and we show analytically that this transition occurs at a certain reduced electric field for the NRP discharges studied here. This model shows that the electrode geometry plays an important role in the existence of the NRP glow regime at a given gas temperature. We derive a criterion for the existence of the NRP glow regime as a function of the ambient gas temperature, pulse repetition frequency, electrode radius of curvature, and interelectrode gap distance.

  16. Glow discharge processing vs bakeout for aluminum storage ring vacuum chambers

    International Nuclear Information System (INIS)

    Dean, N.R.; Hoyt, E.W.; Palrang, M.T.; Walker, B.G.

    1977-11-01

    Experiments were carried out on laboratory and prototype scale systems in order to establish the feasibility of argon discharge processing the PEP storage ring aluminum vacuum chambers. Electron-induced desorption rates showed significant reductions following bakeout and/or argon glow discharge treatment (>10 19 ions cm -1 ). Data are presented and discussed in relation to advantages and problems associated with: water removal, argon trapping and subsequent release, electron energy dependence, discharge distribution, and surface plasma chemical effects

  17. Clostridium beijerinckii mutant obtained atmospheric pressure glow discharge generates enhanced electricity in a microbial fuel cell.

    Science.gov (United States)

    Liu, Jun; Guo, Ting; Wang, Dong; Ying, Hanjie

    2015-01-01

    A Clostridium beijerinckii mutant M13 was derived from C. beijerinckii NCIMB 8052 by atmospheric pressure glow discharge. C. beijerinckii M13 generated a maximum output power density of 79.2 mW m(-2) and a maximum output voltage of 230 mV in a microbial fuel cell containing 1 g glucose l(-1) as carbon source and 0.15 g methyl viologen l(-1) as an electron carrier.

  18. Aligned Carbon Nanotubes Array by DC Glow Plasma Etching for Supercapacitor

    Directory of Open Access Journals (Sweden)

    Yongfeng Luo

    2013-01-01

    Full Text Available To open the end of carbon nanotubes and make these ends connect with functional carboxyl group, aligned carbon nanotubes (CNTs arrays was etched by DC glow oxygen-argon plasma. With these open-ended carbon nanotubes array as electrode materials to build supercapacitor, we found that the capacity (32.2 F/g increased significantly than that of pure carbon nanotubes (6.7 F/g.

  19. Cathode fall parameters of a self-sustained normal glow discharge in atmospheric-pressure helium

    International Nuclear Information System (INIS)

    Arkhipenko, V.I.; Zgirovskii, S.M.; Kirillov, A.A.; Simonchik, L.V.

    2002-01-01

    Results from comprehensive studies of a high-current self-sustained glow discharge in atmospheric-pressure helium are presented. The main parameters of the cathode fall, namely, the electric field profile, cathode fall thickness, current density, gas temperature, and heat flux to the cathode are determined. The results obtained are discussed using one-dimensional models of the cathode fall with allowance for volumetric heat release

  20. Hardening of alloys in glow discharge with the use of pulsed electric current

    International Nuclear Information System (INIS)

    Shipko, M.N.; Pomel'nikova, A.S.; Solunin, A.M.; Solunin, M.A.

    2002-01-01

    The effect of ex/ternal pulsed electric field on the thickness of a hardened surface layer of a Nd-Fe-B system alloy during chemical heat treatment in a glow discharge is studied. The relationship is established between the hardened layer thickness and the frequency of external electric field which is verified by derived equations for the relation between electron energy and pulsed electric field frequency [ru

  1. Glow-discharge-created electron beams and beam-excited lasers

    International Nuclear Information System (INIS)

    Meyer, J.D.

    1989-01-01

    Efficiently created glow discharge electron beams have been developed and studied in detail. The beam mode of operation occurs in the abnormal glow adjacent to the glow-to-arc transition regime. In contrast to electron beams generated in high vacuum from thermionic electron emitting sources, this type of discharge creates electrons directly in soft vacuum by secondary electron emission from cold cathode surfaces following the bombardment of the cathode surface by fast ions and neutral atoms. Factors influencing the efficient electron emission from cold cathodes are presented with emphasis on cathode materials. Sintered ceramic-metal cathodes and oxide-coated cathodes are presented, both of which can produce high power, efficiently generated, d.c. electron beams with discharge currents up to 1 amp (∼130 mA/cm 2 ) at volt ages of up to 6 kV. Novel cathode designs and discharge geometries are presented with specific emphasis on both self-focussed beams emitted from circular cathodes and line-source electron beams emitted from rectangular cathodes forming a thin sheet of electrons. Electrostatically focussed line-source electron beams are spatially characterized by experimentally measuring the effect of discharge parameters and cathode design upon the focussed beam width, focal point, and uniformity. This is achieved by scanning a current collecting detector in three dimensions in order to profile the distribution of electron beam current. Discharge electron beams are further characterized by their electron energy distribution. Measured electron flux energy distributions of transmitted beam electrons in the negative glow are compared to theoretical models. The relative effects of elastic and inelastic collisions mechanisms upon both the overall form and detailed structure of the energy distribution are discussed

  2. Optical observations of Magnetosphere-Ionosphere coupling: Inter-hemispheric electron reflections within pulsating aurora

    Science.gov (United States)

    Samara, M.; Michell, R.; Khazanov, G. V.; Grubbs, G. A., II

    2017-12-01

    Magnetosphere-Ionosphere coupling is exhibited in reflected primary and secondary electrons which constitute the second step in the formation of the total precipitating electron distribution. While they have largely been missing from the current theoretical studies of particle precipitation, ground based observations point to the existence of a reflected electron population. We present evidence that pulsating aurora is caused by electrons bouncing back and forth between the two hemispheres. This means that these electrons are responsible for some of the total light in the aurora, a possibility that has largely been ignored in theoretical models. Pulsating auroral events imaged optically at high time resolution present direct observational evidence in agreement with the inter-hemispheric electron bouncing predicted by the SuperThermal Electron Trans-port (STET) model. Immediately following each of the `pulsation-on' times are equally spaced, and subsequently fainter pulsations, which can be explained by the primary precipitating electrons reflecting upwards from the ionosphere, traveling to the opposite hemisphere, and reflecting upwards again. The high time-resolution of these data, combined with the short duration of the `pulsation-on' time ( 1 s) and the relatively long spacing between pulsations ( 6 to 9 s) made it possible to observe the faint optical pulses caused by the reflected electrons coming from the opposite hemisphere. These results are significant and have broad implications because they highlight that the formation of the auroral electron distributions within regions of diffuse and pulsating aurora contain contributions from reflected primary and secondary electrons. These processes can ultimately lead to larger fluxes than expected when considering only the primary injection of magnetospheric electrons.

  3. Simultaneous measurement of aurora-related, irregular magnetic pulsations at northern and southern high latitudes

    International Nuclear Information System (INIS)

    Arnoldy, R.L.; Rajashekar, R.; Cahill, L.J. Jr.; Engebretson, M.J.; Rosenberg, T.J.; Mende, S.B.

    1987-01-01

    A dominant feature of high-latitude magnetic pulsations is large-amplitude irregular pulsations (Pi) which are closely correlated with the movement of the observing station under particle precipitation, producing the dayside auroral and the high-latitude expansion of nightside aurora. The dayside Pi-1 pulsation maximum centered about local magnetic noon has no strong seasonal dependence, indicating that the dayside aurora illuminates both hemispheres independent of the latitude of the subsolar point. The summer noon pulsation maximum has, however, a greater longitudinal extent than the winter noon maximum, as measured at 74 degree-75 degree invariant latitude. The nightside magnetic pulsations are bursts of Pi (PiB) having an average duration of 15 min. From Defense Meteorological Satellite Program photos the auroral forms related to the high-latitude PiB can be identified as the poleward discrete arc generally having a large longitudinal extent. If the auroral forms are very similar in both hemispheres, then the large longitudinal extent coupled with movement of the auroral could explain why 85% of the PiB events have onsets within 10 min at opposite hemisphere sites (South Pole, Antarctica, and Sondre Stromfjord, Greenland) separated in local magnetic time by about 1.5 hours. There is no seasonal dependence in the statistical occurrence of PiB, nor in its simultaneity in opposite hemispheres. Apparently, the seasonal distortion of the tail plasma sheet has little effect on the acceleration of high-latitude auroral beams. The actual several minute time difference in opposite hemisphere onsets of PiB is probably due to the westward/poleward motion of the longitudinally extended aurora

  4. The aurora at quite magnetospheric conditions: Repeatability and dipole tilt angle dependence

    International Nuclear Information System (INIS)

    Oznovich, I.; Eastes, R.W.; Huffman, R.E.; Tur, M.; Glaser, I.

    1993-01-01

    Is there a magnetospheric ground state? Do the position and size of the auroral oval depend on the magnetic dipole tilt angle at quiet magnetospheric conditions? In order to address these questions, northern hemisphere images of the aurora at 1356 Angstrom, obtained by Polar BEAR at solar minimum (beginning of 1987), were related to high temporal resolution IPM 8 measurements of the interplanetary magnetic field, to solar wind velocity, and to the ground-based activity index Kp. The first problem was addressed by a two-dimensional correlation study of the repeatability of auroral emissions in corrected geomagnetic space at conditions of minimum energy transfer from the magnetosphere. The correlation measure of auroral images was 0.6-0.85. Error simulations indicate that given the uncertainties in pixel position and intensity, the maximum expected value of the correlation measure is 0.65-0.9. The notion of a ground state magnetosphere is therefore supported by this data. Repeatability was found at the same level regardless of time or reconfigurations of the magnetosphere between images and independent of magnetic time sector. The second problem was addressed by relating latitudinal shifts of the aurora with dipole tilt angle without resorting to auroral boundary specification. This data indicate that the latitude of the continuous aurora is related to the dipole tilt angle at quiet magnetospheric conditions. In the winter hemisphere a 10 degrees increase in the dipole tilt angle causes a 1 degree decrease (increase) in the latitude of auroral emissions at noon (midnight). The magnetic local time distribution of the latitudinal shifts with dipole tilt angle support a simple model in which the dipole tilt angle determines the position of the center of the auroral circle along the magnetic meridian 1320-0120 MLT (for IMF B y positive) and does not affect its radius. 22 refs., 8 figs

  5. Boundary Effect of Planar Glow Dielectric Barrier Discharge and Its Influence on the Discharge Structure

    International Nuclear Information System (INIS)

    Xu Shaowei; Li Lulu; Ouyang Jiting

    2015-01-01

    The dielectric barrier discharge (DBD) in the glow regime in neon has been investigated by experiment and two-dimensional (2D) fluid modeling. The discharge was carried out in a planar DBD system with segmented-electrodes driven by square-wave voltage. The results show that the glow DBD originates in the center of the electrode and expands outward to the electrode edge during each half cycle of the voltage, forming a radial structure. The discharge decays firstly in the inner area but sustains longer in the edge area, showing a reversed discharge area. The discharge cannot completely cover the entire electrode surface, but remains a border of non- or weak discharge. The fluid modeling shows a similar result in agreement with the experiments. The simulations indicate that the electric field in the edge area is distorted due to the boundary effect so that the electric field and charge distribution are different from that in the inner part. The distorted field reduces the longitudinal component near the edge and causes the local field to be lower than that in the center, and hence makes the discharge behindhand. It also induces a transverse field that makes the discharge extend radially outward to the edge. The boundary effect plays an important role in the glow DBD structure. (paper)

  6. Discharge current characteristics as an 'electrical method' for glow discharge plasma diagnosis

    International Nuclear Information System (INIS)

    Toma, M.; Paraschivescu, Alina; Morminches, Anisoara

    2001-01-01

    In its simplest form, the glow discharge can be established by passing an electric current through gas between two electrodes. The gas and the electrodes are contained in an insulating envelope. In many technological applications, and not only, the plasma devices are often treated like a black box. There is a series of external parameters or control variables which can be adjusted to obtain a desired effect, namely, the operating voltage, gas pressure, gas nature, gas flow rate, magnetic field strength and magnetic field configuration, electric field geometry, interelectrode distance, and cathode characteristics. The discharge current can be controlled by each of the above control variables. The core idea of this work is the following: a lot of information about the phenomena from the discharge volume, at electrodes or at the discharge bounding wall surface, can be obtained knowing how the change of one of the control parameters influences the discharge current. The following regimes were analyzed: dark discharges (background ionization, saturation regime, Townsend regime, corona regime), glow discharge (the normal and abnormal discharge) and arc discharge (glow to arc transition, non-thermal arcs, thermal arcs). It was concluded that the nonlinearity in the shape of the discharge current characteristics as a function of an external control parameter, can be correlated with the elementary processes and the dynamics of different space charge structures generated in plasma devices. (authors)

  7. Studies on the Electrical Characteristics of a DC Glow Discharge by Using Langmuir Probe

    International Nuclear Information System (INIS)

    Safaai, S. S.; Yap, S. L.; Wong, C. S.; Muniandy, S. V.; Smith, P. W.

    2010-01-01

    Electrical characteristics of a DC glow discharge are studied with the aim of determining the suitable parameters for stable operation of the dusty plasma system. The presence of dust particles in plasma significantly alters the charged particle equilibrium in the plasma and leads to various phenomena. Argon plasma produced by DC glow discharge is investigated with a further goal of studying dusty plasma phenomena. The discharge system has two disc-shaped parallel plate electrodes. The electrodes are enclosed in a large cylindrical stainless steel chamber filled with argon gas. Two important physical parameters affecting the condition of the discharge are the gas pressure and the inter-electrode distance. A single Langmuir probe based on the Keithley source meter is used to determine the electron temperature of the positive column. A custom designed probe is employed to determine the potential distribution between the electrodes during the discharge. The I-V characteristic curve and the Langmuir probe measurement are then used to determine the electron energy distribution of the glow discharge plasma.

  8. Particle control in DIII-D with helium glow discharge conditioning

    International Nuclear Information System (INIS)

    Jackson, G.L.; Taylor, T.S.; Taylor, P.L.

    1990-01-01

    Helium glow discharge conditioning of DIII-D is routinely used before every tokamak discharge to desorb hydrogen from the graphite tiles, which are the plasma facing surfaces for the floor, inner wall and top of the vessel. In addition to reducing hydrogen fuelling of the plasma by the graphite surfaces, helium glow discharges are also effective in removing low-Z impurities, primarily in the form of carbon monoxide and hydrocarbons, and this has permitted higher current divertor operation and more rapid recovery from tokamak disruptions. Since the implementation of repetitive helium glow wall conditioning, the parameter space in which tokamak discharges in DIII-D can be obtained has been expanded to include the first observations of limiter H-mode confinement, the Ohmic H-mode with periods of up to 150 ms that are free of edge localized modes, more reliable low q operation with volume averaged beta of up to 9.3%, improved control over locked modes and plasma discharges at lower electron density. (author). 37 refs, 12 figs, 1 tab

  9. Application of Glow Curve Deconvolution Method to Evaluate Low Dose TLD LiF

    International Nuclear Information System (INIS)

    Kurnia, E; Oetami, H R; Mutiah

    1996-01-01

    Thermoluminescence Dosimeter (TLD), especially LiF:Mg, Ti material, is one of the most practical personal dosimeter in known to date. Dose measurement under 100 uGy using TLD reader is very difficult in high precision level. The software application is used to improve the precision of the TLD reader. The objectives of the research is to compare three Tl-glow curve analysis method irradiated in the range between 5 up to 250 uGy. The first method is manual analysis, dose information is obtained from the area under the glow curve between pre selected temperature limits, and background signal is estimated by a second readout following the first readout. The second method is deconvolution method, separating glow curve into four peaks mathematically and dose information is obtained from area of peak 5, and background signal is eliminated computationally. The third method is deconvolution method but the dose is represented by the sum of area of peak 3,4 and 5. The result shown that the sum of peak 3,4 and 5 method can improve reproducibility six times better than manual analysis for dose 20 uGy, the ability to reduce MMD until 10 uGy rather than 60 uGy with manual analysis or 20 uGy with peak 5 area method. In linearity, the sum of peak 3,4 and 5 method yields exactly linear dose response curve over the entire dose range

  10. Micro glow plasma for localized nanostructural modification of carbon nanotube forest

    Energy Technology Data Exchange (ETDEWEB)

    Sarwar, Mirza Saquib us; Xiao, Zhiming; Saleh, Tanveer; Nojeh, Alireza; Takahata, Kenichi [University of British Columbia, Vancouver, British Columbia V6T 1Z4 (Canada)

    2016-08-22

    This paper reports the localized selective treatment of vertically aligned carbon nanotubes, or CNT forests, for radial size modification of the nanotubes through a micro-scale glow plasma established on the material. An atmospheric-pressure DC glow plasma is shown to be stably sustained on the surface of the CNT forest in argon using micromachined tungsten electrodes with diameters down to 100 μm. Experiments reveal thinning or thickening of the nanotubes under the micro glow depending on the process conditions including discharge current and process time. These thinning and thickening effects in the treated nanotubes are measured to be up to ∼30% and ∼300% in their diameter, respectively, under the tested conditions. The elemental and Raman analyses suggest that the treated region of the CNT forest is pure carbon and maintains a degree of crystallinity. The local plasma treatment process investigated may allow modification of material characteristics in different domains for targeted regions or patterns, potentially aiding custom design of micro-electro-mechanical systems and other emerging devices enabled by the CNT forest.

  11. Low-pressure glow discharges with oscillating electrons in different electrode systems

    International Nuclear Information System (INIS)

    Bersenev, V.V.; Gavriolv, N.V.; Nikulin, S.P.

    1995-01-01

    One of the main applications of low - pressure glow discharges is the development on their basis of charged - particle beam sources. The use of glow discharges with oscillating electrons, which can operate stably in the voltage and pressure range to the left of the left branch of Pashen's curve, shows promise, because the decrease in critical pressure p 0 , below which the discharge operation becomes impossible, in the discharge system of a source promotes an increase in the electrical strength of its accelerating system. This, in its turn, makes possible the expansion of the operation range of accelerating voltages. This experimental investigation of glow discharges in such well - known systems with oscillating electrons, as Hollow Cathode (HC), Penning's System (PS) and Inverse Magnetron (IM), is aimed at revealing the system operating at the lowest pressure. Besides, both common features and peculiarities of discharge operation in these systems are discussed. Though there is an extensive amount of published information covering all the specified discharges, the carrying out of such investigation is justified, since a comparative analysis of results obtained by different authors is hampered by various conditions of their experiments

  12. The impact of molecular emission in compositional depth profiling using Glow Discharge-Optical Emission Spectroscopy

    International Nuclear Information System (INIS)

    Bengtson, Arne

    2008-01-01

    The scope of this paper is to investigate and discuss how molecular emission can affect elemental analysis in glow discharge optical emission (GD-OES), particularly in compositional depth profiling (CDP) applications. Older work on molecular emission in glow discharges is briefly reviewed, and the nature of molecular emission spectra described. Work on the influence of hydrogen in the plasma, in particular elevated background due to a continuum spectrum, is discussed. More recent work from sputtering of polymers and other materials with a large content of light elements in a Grimm type source is reviewed, where substantial emission has been observed from several light diatomic molecules (CO, CH, OH, NH, C 2 ). It is discussed how the elevated backgrounds from such molecular emission can lead to significant analytical errors in the form of 'false' depth profile signals of several atomic analytical lines. Results from a recent investigation of molecular emission spectra from mixed gases in a Grimm type glow discharge are presented. An important observation is that dissociation and subsequent recombination processes occur, leading to formation of molecular species not present in the original plasma gas. Experimental work on depth profiling of a polymer coating and a thin silicate film, using a spectrometer equipped with channels for molecular emission lines, is presented. The results confirm that molecular emission gives rise to apparent depth profiles of elements not present in the sample. The possibilities to make adequate corrections for such molecular emission in CDP of organic coatings and very thin films are discussed

  13. Methane Conversion to C2 Hydrocarbons by Abnormal Glow Discharge at Atmospheric Pressure

    International Nuclear Information System (INIS)

    Dai Wei; Yu Hui; Chen Qi; Yin Yongxiang; Dai Xiaoyan

    2005-01-01

    Methane conversion to C 2 hydrocarbons has been investigated with the addition of hydrogen in a plasma reactor of abnormal glow discharge at atmospheric pressure. The aim of this experiment is to minimize coke formation and improve discharge stability. The typical conditions in the experiment are 300 ml of total feed flux and 400 W of discharge power. The experimental results show that methane conversion is from 91.6% to 35.2% in mol, acetylene selectivity is from 90.2% to 57.6%, and ethylene selectivity is approximately from 7.8% to 3.6%, where the coke increases gradually along with the increase of CH 4 /H 2 from 2: 8 to 9: 1. A stable discharge for a considerable running time can be obtained only at a lower ratio of CH 4 /H 2 2: 8 or 3: 7. These phenomena indicate that the coke deposition during methane conversion is obviously reduced by adding a large amount of hydrogen during an abnormal glow discharge. A qualitative interpretation is presented, namely, with abundant hydrogen, the possibility that hydrogen molecules are activated to hydrogen radicals is increased with the help of the abnormal glow discharge. These hydrogen radicals react with carbon radicals to form C 2 hydrocarbon products. Therefore, the deposition of coke is restrained

  14. Fit of second order thermoluminescence glow peaks using the logistic distribution function

    International Nuclear Information System (INIS)

    Pagonis, V.; Kitis, G.

    2001-01-01

    A new thermoluminescence glow curve deconvolution (GCD) function is introduced which accurately describes second order thermoluminescence (TL) curves. The logistic asymmetric (LA) statistical probability function is used with the function variables being the maximum peak intensity (I m ), the temperature of the maximum peak intensity (T m ) and the LA width parameter a 2 . An analytical expression is derived from which the activation energy E can be calculated as a function of T m and the LA width parameter a 2 with an accuracy of 2% or better. The accuracy of the fit was tested for E values ranging from 0.7 to 2.5 eV, for s values between 10 5 and 10 25 s -1 , and for trap occupation number n 0 /N between 1 and 10 -6 . The goodness of fit of the logistic asymmetric function is described by the Figure of Merit (FOM) which is found to be of the order of 10 -2 . Preliminary results show that the GCD described here can easily be extended to the description of general order TL glow curves by varying the asymmetry parameter of the logistic asymmetric function. It is concluded that the TL kinetic analysis of first, second and general order TL glow curves can be performed with high accuracy and speed by using commercially available statistical packages that incorporate the Weibull and logistic asymmetric functions. (author)

  15. A comparison of hydrogen vs. helium glow discharge effects on fusion device first-wall conditioning

    International Nuclear Information System (INIS)

    Dylla, H.F.

    1989-09-01

    Hydrogen- and deuterium-fueled glow discharges are used for the initial conditioning of magnetic fusion device vacuum vessels following evacuation from atmospheric pressure. Hydrogenic glow discharge conditioning (GDC) significantly reduces the near-surface concentration of simple adsorbates, such as H 2 O, CO, and CH 4 , and lowers ion-induced desorption coefficients by typically three orders of magnitude. The time evolution of the residual gas production observed during hydrogen-glow discharge conditioning of the carbon first-wall structure of the TFTR device is similar to the time evolution observed during hydrogen GDC of the initial first-wall configuration in TFTR, which was primarily stainless steel. Recently, helium GDC has been investigated for several wall-conditioning tasks on a number of tokamaks including TFTR. Helium GDC shows negligible impurity removal with stainless steel walls. For impurity conditioning with carbon walls, helium GDC shows significant desorption of H 2 O, CO, and CO 2 ; however, the total desorption yield is limited to the monolayer range. In addition, helium GDC can be used to displace hydrogen isotopes from the near-surface region of carbon first-walls in order to lower hydrogenic retention and recycling. 38 refs., 6 figs

  16. An Investigation of LED Street Lighting's Impact on Sky Glow

    Energy Technology Data Exchange (ETDEWEB)

    Kinzey, Bruce R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Perrin, Tess E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Miller, Naomi J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kocifaj, Miroslav [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Aube, Martin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lamphar, Hector A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-04-25

    A significant amount of public attention has recently focused on perceived impacts of converting street lighting from incumbent lamp-based products to LED technology. Much of this attention pertains to the higher content of short wavelength light (commonly referred to as "blue light") of LEDs and its attendant influences on sky glow (a brightening of the night sky that can interfere with astronomical observation and may be associated with a host of other issues). The complexity of this topic leads to common misunderstandings and misperceptions among the public, and for this reason the U.S. Department of Energy Solid-State Lighting Program embarked on a study of sky glow using a well-established astronomical model to investigate some of the primary factors influencing sky glow. This report details the results of the investigation and attempts to present those results in terms accessible to the general lighting community. The report also strives to put the results into a larger context, and help educate interested readers on various topics relevant to the issues being discussed.

  17. On the variability of I(7620 Å/I(5577 Å in low altitude aurora

    Directory of Open Access Journals (Sweden)

    E. J. Llewellyn

    1999-07-01

    Full Text Available An auroral electron excitation model, combined with simple equilibrium neutral and ion chemistry models, is used to investigate the optical emission processes and height profiles of I(5577 Å and I(7620 Å in the 90 to 100 km altitude region. It is shown that the apparent discrepancies between ground-based and rocket-borne auroral observations of the I(7620 Å/I(5577 Å ratio are due to the extreme height variation of this intensity ratio in the 90 to 100 km region.Key words. Atmospheric composition and structure (airglow and aurora

  18. Indole Alkaloids from the Sea Anemone Heteractis aurora and Homarine from Octopus cyanea.

    Science.gov (United States)

    Shaker, Kamel H; Göhl, Matthias; Müller, Tobias; Seifert, Karlheinz

    2015-11-01

    The two new indole alkaloids 2-amino-1,5-dihydro-5-(1H-indol-3-ylmethyl)-4H-imidazol-4-one (1), 2-amino-5-[(6-bromo-1H-indol-3-yl)methyl]-3,5-dihydro-3-methyl-4H-imidazol-4-one (2), and auramine (3) have been isolated from the sea anemone Heteractis aurora. Both indole alkaloids were synthesized for the confirmation of the structures. Homarine (4), along with uracil (5), hypoxanthine (6), and inosine (7) have been obtained from Octopus cyanea. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

  19. On the variability of I(7620 Å/I(5577 Å in low altitude aurora

    Directory of Open Access Journals (Sweden)

    E. J. Llewellyn

    Full Text Available An auroral electron excitation model, combined with simple equilibrium neutral and ion chemistry models, is used to investigate the optical emission processes and height profiles of I(5577 Å and I(7620 Å in the 90 to 100 km altitude region. It is shown that the apparent discrepancies between ground-based and rocket-borne auroral observations of the I(7620 Å/I(5577 Å ratio are due to the extreme height variation of this intensity ratio in the 90 to 100 km region.

    Key words. Atmospheric composition and structure (airglow and aurora

  20. Aurora-B Mediated ATM Serine 1403 Phosphorylation Is Required For Mitotic ATM Activation and the Spindle Checkpoint

    OpenAIRE

    Yang, Chunying; Tang, Xi; Guo, Xiaojing; Niikura, Yohei; Kitagawa, Katsumi; Cui, Kemi; Wong, Stephen T.C.; Fu, Li; Xu, Bo

    2011-01-01

    The ATM kinase plays a critical role in the maintenance of genetic stability. ATM is activated in response to DNA damage and is essential for cell cycle checkpoints. Here, we report that ATM is activated in mitosis in the absence of DNA damage. We demonstrate that mitotic ATM activation is dependent on the Aurora-B kinase and that Aurora-B phosphorylates ATM on serine 1403. This phosphorylation event is required for mitotic ATM activation. Further, we show that loss of ATM function results in...

  1. Expression of aurora kinase A is associated with metastasis-free survival in node-negative breast cancer patients

    International Nuclear Information System (INIS)

    Siggelkow, Wulf; Koelbl, Heinz; Gehrmann, Mathias; Marchan, Rosemarie; Cadenas, Cristina; Hengstler, Jan G; Schmidt, Marcus; Boehm, Daniel; Gebhard, Susanne; Battista, Marco; Sicking, Isabel; Lebrecht, Antje; Solbach, Christine; Hellwig, Birte; Rahnenführer, Jörg

    2012-01-01

    Inhibitors targeting the cell cycle-regulated aurora kinase A (AURKA) are currently being developed. Here, we examine the prognostic impact of AURKA in node-negative breast cancer patients without adjuvant systemic therapy (n = 766). AURKA was analyzed using microarray-based gene-expression data from three independent cohorts of node-negative breast cancer patients. In multivariate Cox analyses, the prognostic impact of age, histological grade, tumor size, estrogen receptor (ER), and HER2 were considered. Patients with higher AURKA expression had a shorter metastasis-free survival (MFS) in the Mainz (HR 1.93; 95% CI 1.34 – 2.78; P < 0.001), Rotterdam (HR 1.95; 95% CI 1.45– 2.63; P<0.001) and Transbig (HR 1.52; 95% CI 1.14–2.04; P=0.005) cohorts. AURKA was also associated with MFS in the molecular subtype ER+/HER2- carcinomas (HR 2.10; 95% CI 1.70–2.59; P<0.001), but not in ER-/HER2- nor in HER2+ carcinomas. In the multivariate Cox regression adjusted to age, grade and tumor size, AURKA showed independent prognostic significance in the ER+/HER2- subtype (HR 1.73; 95% CI 1.24–2.42; P=0.001). Prognosis of patients in the highest quartile of AURKA expression was particularly poor. In addition, AURKA correlated with the proliferation metagene (R=0.880; P<0.001), showed a positive association with grade (P<0.001), tumor size (P<0.001) and HER2 (P<0.001), and was inversely associated with ER status (P<0.001). AURKA is associated with worse prognosis in estrogen receptor positive breast carcinomas. Patients with the highest AURKA expression (>75% percentile) have a particularly bad prognosis and may profit from therapy with AURKA inhibitors

  2. Characterization of the large area plane-symmetric low-pressure DC glow discharge

    Science.gov (United States)

    Avtaeva, S.; Gorokhovsky, V.; Myers, S.; Robertson, S.; Shunko, E.; Zembower, Z.

    2016-10-01

    Electron density and temperature as well as nitrogen dissociation degree in the low-pressure (10-50 mTorr) large area plane-symmetric DC glow discharge in Ar-N2 mixtures are studied by probes and spectral methods. Electron density measured by a hairpin probe is in good agreement with that derived from the intensity ratio of the N2 2nd positive system bands IC, 1 - 3/IC, 0 - 2 and from the intensity ratio of argon ions and atom lines IArII/IArI, while Langmuir probe data provides slightly higher values of electron density. Electron density in the low-pressure DC glow discharge varies with the discharge conditions in the limits of 108-1010 cm- 3. The concept of electron temperature can be used in low-pressure glow discharges with reservations. The intensity ratio of (0-0) vibrational bands of N2 1st negative and 2nd positive systems I391.4/I337.1 exhibits the electron temperature of 1.5-2.5 eV when argon fraction in the mixture is higher than nitrogen fraction and this ratio quickly increases with nitrogen fraction up to 10 eV in pure nitrogen. The electron temperature calculated from Langmuir probe I-V characteristics assuming a Maxwellian EEDF, gives Te 0.3-0.4 eV. In-depth analysis of the EEDF using the second derivative of Langmuir probe I-V characteristics shows that in a low-pressure glow discharge the EEDF is non-Maxwellian. The EEDF has two populations of electrons: the main background non-Maxwellian population of ;cold; electrons with the mean electron energy of 0.3-0.4 eV and the small Maxwellian population of ;hot; electrons with the mean electron energy of 1.0-2.5 eV. Estimations show that with electron temperature lower than 1 eV the rate of the direct electron impact ionization of N2 is low and the main mechanism of N2 ionization becomes most likely Penning and associative ionization. In this case, assumptions of the intensity ratio IN2+, 391/IN2, 337 method are violated. In the glow discharge, N2 dissociation degree reaches about 7% with the argon

  3. 7 CFR 301.38-2 - Regulated articles.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Regulated articles. 301.38-2 Section 301.38-2... atropurpurea 'Redbird' B. thunbergii atropurpurea 'Rose Glow' B. thunbergii aurea B. thunbergii 'Aurea Nana' B... paragraphs (a)(1) through (a)(3) of this section that an inspector determines presents a risk of spread of...

  4. Precipitation of relativistic electrons of the Van Allen belts into the proton aurora

    International Nuclear Information System (INIS)

    Jordanova, Vania K.; Miyoshi, Y.; Sakaguchi, K.; Shiokawa, K.; Evans, D.S.; Albert, Jay; Connors, M

    2008-01-01

    The Van Allen electron belts consist of two regions encircling the earth in which relativistic electrons are trapped in the earth's magnetic field. Populations of relativistic electrons in the Van Allen belts vary greatly with geomagnetic disturbance and they are a major source of damage to space vehicles. In order to know when and by how much these populations of relativistic electrons increase, it is important to elucidate not only the cause of acceleration of relativistic electrons but also the cause of their loss from the Van Allen belts. Here we show the first evidence that left-hand polarized electromagnetic ion cyclotron (EMIC) plasma waves can cause the loss of relativistic electrons into the atmosphere, on the basis of results of an excellent set of ground and satellite observations showing coincident precipitation of ions with energies of tens of keV and of relativistic electrons into an isolated proton aurora. The proton aurora was produced by precipitation of ions with energies of tens of keV due to EMIC waves near the plasma pause, which is a manifestation of wave-particle interactions. These observations clarify that ions with energies of tens of keV affect the evolution of relativistic electrons in the Van Allen belts via parasitic resonance with EMIC waves, an effect that was first theoretically predicted in the early 1970's

  5. Improved performance of the Aurora KrF/ICF laser system

    International Nuclear Information System (INIS)

    Jones, J.E.; Czuchlewski, S.J.; Turner, T.P.; Watt, R.G.; Thomas, S.J.; Netz, D.A.; Tallman, C.R.; Figueira, J.F.

    1990-01-01

    This paper reports on Aurora the Los Alamos National Laboratory short pulse high power krypton-fluoride laser system. It serves as an end-to-end technology demonstration prototype for large scale UV laser systems for short wavelength inertial confinement fusion (ICF) research. The system employs optical angular multiplexing and serial amplification by electron-beam driven KrF laser amplifiers. The 1-5-ns pulse of the Aurora front end is split into ninety-six beams which are angularly and temporally multiplexed to produce a 480-ns pulse train for amplification by four KrF laser amplifiers. The largest amplifier, the large aperture module (LAM), has a 1-m square aperture and a gain length of 2 m. In the present system configuration half (forty-eight) of the amplified pulses are demultiplexed using different optical path lengths and delivered simultaneously to target. The system has not been optimized, and several near term improvements are expected to result in significant increases in both delivered energy and target irradiance. Removing the twelve calorimeters from the lens plate and allowing forty-eight beams to go to target will increase delivered energy by 33%. Relatively minor modifications to the front end should result in a 30% increase in system output energy. Replacement of damaged optics will increase transmission into the preamplifier by at least 25%. New optics and reduction of retro-pulses will allow the preamplifier stage gain to be increased by 50%

  6. Integration of the Aurora KrF ICF laser system at Los Alamos

    International Nuclear Information System (INIS)

    Rosocha, L.A.; Blair, L.S.

    1988-01-01

    The Aurora laser system, under construction at the Los Alamos National Laboratory for the past few years, is now being integrated into a working system for examining the applicability of high-power KrF lasers to inertial confinement fusion (ICF). The design principles of the system have been described in detail in earlier publications and conferences. Multikilojoule 248-nm 5-ns duration laser pulses, which have been derived from angular-multiplexed electron-beam-driven KrF amplifiers, are to be delivered to ICF targets when the system is fully integrated. The authors describe the progress of the Aurora system toward the goal of delivering energy (MkJ/48 pulses stacked into one 5-ns pulse/200-μm spot) to ICF targets. Integrated performance to date of the front end optical multiplexer/demultiplexer e-beam-driven amplifiers and alignment hardware are discussed in particular. They have concentrated on the demonstration of system integration at a modest (--100-J) level of energy on-target (without the final amplifier stage). They discuss the amplifier gain measurements, the extraction of energy from a chain of three e-beam-driven machines, and progress toward the delivery of on-target energy

  7. Jupiter's Aurora Observed With HST During Juno Orbits 3 to 7

    Science.gov (United States)

    Grodent, Denis; Bonfond, B.; Yao, Z.; Gérard, J.-C.; Radioti, A.; Dumont, M.; Palmaerts, B.; Adriani, A.; Badman, S. V.; Bunce, E. J.; Clarke, J. T.; Connerney, J. E. P.; Gladstone, G. R.; Greathouse, T.; Kimura, T.; Kurth, W. S.; Mauk, B. H.; McComas, D. J.; Nichols, J. D.; Orton, G. S.; Roth, L.; Saur, J.; Valek, P.

    2018-05-01

    A large set of observations of Jupiter's ultraviolet aurora was collected with the Hubble Space Telescope concurrently with the NASA-Juno mission, during an eight-month period, from 30 November 2016 to 18 July 2017. These Hubble observations cover Juno orbits 3 to 7 during which Juno in situ and remote sensing instruments, as well as other observatories, obtained a wealth of unprecedented information on Jupiter's magnetosphere and the connection with its auroral ionosphere. Jupiter's ultraviolet aurora is known to vary rapidly, with timescales ranging from seconds to one Jovian rotation. The main objective of the present study is to provide a simplified description of the global ultraviolet auroral morphology that can be used for comparison with other quantities, such as those obtained with Juno. This represents an entirely new approach from which logical connections between different morphologies may be inferred. For that purpose, we define three auroral subregions in which we evaluate the auroral emitted power as a function of time. In parallel, we define six auroral morphology families that allow us to quantify the variations of the spatial distribution of the auroral emission. These variations are associated with changes in the state of the Jovian magnetosphere, possibly influenced by Io and the Io plasma torus and by the conditions prevailing in the upstream interplanetary medium. This study shows that the auroral morphology evolved differently during the five 2 week periods bracketing the times of Juno perijove (PJ03 to PJ07), suggesting that during these periods, the Jovian magnetosphere adopted various states.

  8. Generation of ninety-six angularly multiplexed KrF beams at Aurora

    International Nuclear Information System (INIS)

    Rose, E.A.

    1987-01-01

    The Aurora KrF laser facility is designed to produce ninety-six laser beams at 248 nm with total energy of -- 10 kJ. The 5-ns duration beams are angularly multiplexed to allow sequential amplification in electron-beam-pumped amplifiers. These amplifiers operated over a half-microsecond period. Previous to this investigation, all individual components of the Aurora system have been operated independently. As a first step toward integration of the full system, the author operated the front end, beam slicer, small-aperture module (SAM), and angle encoder to generate ninety-six angularly multiplexed beams. These beams have been delivered to the first of the three large amplifiers, which will boost the pulse train energy from <1 J to 10 kJ. Measurements to date have concentrated on the total energy of the pulse train and pulse shapes of the individual beams at positions preceding and following SAM. Measured gain through SAM is -- 13 with 20 the target figure. Relative pulse heights are preserved through SAM with the exception of the first pulse of the 12

  9. Recent progress on the Los Alamos Aurora ICF [inertial confinement fusion] laser system

    International Nuclear Information System (INIS)

    Rosocha, L.A.; Blair, L.S.

    1987-01-01

    Aurora is the Los Alamos short-pulse, high-power, krypton-fluoride laser system. It serves as an end-to-end technology demonstration prototype for large-scale ultraviolet laser systems for short wavelength inertial confinement fusion (ICF) investigations. The system is designed to employ optical angular multiplexing and serial amplification by electron-beam-driven KrF laser amplifiers to deliver stacked, 248-nm, 5-ns duration multikilojoule laser pulses to ICF-relevant targets. This paper presents a summary of the Aurora system and a discussion of the progress achieved in the construction and integration of the laser system. We concentrate on the main features of the following major system components: front-end lasers, amplifier train, multiplexer, optical relay train, demultiplexer, and the associated optical alignment system. During the past year, two major construction and integration tasks have been accomplished. The first task is the demonstration of 96-beam multiplexing and amplified energy extraction, as evidenced by the integrated operation of the front end, the multiplexer (12-fold and 8-fold encoders), the optical relay train, and three electron-beam-driven amplifiers. The second task is the assembly and installation of the demultiplexer optical hardware, which consists of over 300 optical components ranging in size from several centimeters square to over a meter square. 13 refs., 13 figs

  10. Environmental impact assessment - baseline noise survey and noise impact assessment for Aurora Mine

    International Nuclear Information System (INIS)

    Yee, S.

    1996-01-01

    A noise impact assessment was conducted at Syncrude's proposed Aurora Mine site to comply with Alberta Energy and Utilities Board (AEUB) Noise Control Directive ID 94-4. Noise assessments were conducted near a major noise source, i.e. the hydraulic and electric shovels. Noise levels at 50 meters away from the source varied from 72.3 to 79.7 dBA. The worst case noise level was 75 dBA measured at 100 meters away from a hydraulic shovel. This assessment was used to calculate the predicted design sound level from a noise source at the nearest or most impacted occupied dwelling. Two cabins located near the access road and along Kearl Lake respectively, were identified as the most impacted and nearest dwellings to the mine site. The predicted sound level at one cabin was 43 dBA, and 55 dBA at the other. Fort McKay was also assessed because it is the nearest community to the mine site. The sound level at Fort McKay was predicted to be 34 dBA. These results indicate that the sound level from Aurora Mine is not in compliance with the AEUB Noise Control Directive. Attenuation measures are required to reduce the noise to acceptable level at Cabin A and B. Predicted sound level at Fort McKay is lower than the permitted sound level

  11. Floristic Inventory of The Proposed Site for Tarsier Tourism Center in Villa Aurora, Bilar, Bohol, Philippines

    Directory of Open Access Journals (Sweden)

    Tomas D Reyes Jr

    2015-07-01

    Full Text Available The study assessed the present vegetation composition of the Proposed Site for the Tarsier Tourism Center (PTTC at Villa Aurora, Bilar, Bohol and performed a comparative analysis with the existing Tarsier Sanctuary (TS at Canapnapan, Corella, Bohol. The basis for comparison was the computed importance values, species richness, species dominance, and percent distribution of plants according to self-defined DBH classes. Results showed that both sites had very high species richness and evenness values. Common overstorey and understorey plant species found in both areas were katagpo (Psychotria sp., sagimsim (Syzygium brevistylum [C. B. Rob]Merr. and bagauak (Clerodendrum minahassae Teijsm. & Binn.. Apart from sagimsim (Syzygium brevistylum [C.B.Rob.] Merr., selaginella (Selaginella cuppresina Lin., and lunas (Lunasia amara Blanco were also common in the ground vegetation of both areas. Percent distribution of trees according to self-defined DBH classes revealed that PTTC had 87.55% of the total recorded plants with DBH measurements of 20 cm. Percent distribution of trees on these DBH ranges (especially on DBH class >20 cm indicated the presence of medium and large trees. The largest DBH measured in the PTTC was 70 cm while in TS was only 22 cm. The proposed 10-ha site in Villa Aurora, Bilar, is suited to be utilized as Tarsier Tourism Center. In case the proposed project is to be pursued, enclosure similar to what has been constructed in Canapnapan, Corella, Bohol, Philippines should also be established to prevent stray animals from predating the captive tarsiers.

  12. Detection of the 'continuous' H3(+) electrojet in the Jovian Aurora

    Science.gov (United States)

    Stallard, T. S.; Miller, S.; Achilleos, N.; Rego, D.; Prange, R.; Dougherty, M.; Joseph, R. D.

    1999-09-01

    Recently we have published the first detection of an auroral electrojet - a fast ion wind circulating around the auroral oval - on Jupiter (Rego et al., Nature, 399, 121-123). The detection was made during an unusual "auroral event", but raised the possibility that such electrojets might be detectable under "normal" auroral conditions. This work, currently in progress, is directed towards that aim. To accomplish this, high resolution infrared spectra and images of the Jovian aurora were taken on the nights of September 7-11(th) 1998, observing the nu_ {2} Q(1,0(-) ) line of H(+}_{3) at 3.953 mu m. The slit was aligned across the planet, perpendicular to the rotational axis, and the spectra were taken at 1 arcsec steps across the planet through the region of aurora. Each spectrum has been fitted row by row with a gaussian using height, width, background and central position as free parameters. This results in a measurement of how the relative central position varies across each spectra. Having processed the data, removing any systematic array effects, rotation, and instrumentally based spatial effects, we intend to show a measurable electrojet from the dopler shift it causes. This will be in the form of LOS maps of the auroral region at different CML taken over the 5 night observation period.

  13. Analysis of glow curves of TL readouts of CaSO4:Dy teflon based TLD badge in semiautomatic TLD badge reader

    International Nuclear Information System (INIS)

    Pradhan, S.M.; Sneha, C.; Adtani, M.M.

    2010-01-01

    The facility of glow curve storage and recall provided in the reader software is helpful for manual screening of the glow curves; however no further analysis is possible due to absence of numerical TL data at the sampling intervals. In the present study glow curves are digitized by modifying the reader software and then normalized to make them independent of the dose. The normalized glow curves are then analyzed by dividing them into five equal parts on time scale. This method of analysis is used to correlate the variation of total TL counts of the three discs with time elapsed post irradiation

  14. 78 FR 23318 - Trust for Professional Managers and Aurora Investment Management L.L.C.; Notice of Application

    Science.gov (United States)

    2013-04-18

    ... subadvisory agreements (``Subadvisory Agreements'') with Chicago Fundamental Investment Partners, LLC, First... SECURITIES AND EXCHANGE COMMISSION [Investment Company Act Release No. 30460; 812-14113] Trust for Professional Managers and Aurora Investment Management L.L.C.; Notice of Application April 12, 2013. AGENCY...

  15. A Comparative Study of the Aneugenic and Polyploidy-inducing Effects of Fisetin and Two Model Aurora Kinase Inhibitors

    Science.gov (United States)

    Gollapudi, P.; Hasegawa, L.S.; Eastmond, D.A.

    2014-01-01

    Fisetin, a plant flavonol commonly found in fruits, nuts and vegetables, is frequently added to nutritional supplements due to its reported cardioprotective, anti-carcinogenic and antioxidant properties. Earlier reports from our laboratory and others have indicated that fisetin has both aneugenic and clastogenic properties in cultured cells. More recently, fisetin has also been reported to target Aurora B kinase, a Ser/Thr kinase involved in ensuring proper microtubule attachment at the spindle assembly checkpoint, and an enzyme that is overexpressed in several types of cancer. Here we have further characterized the chromosome damage caused by fisetin and compared it with that induced by two known Aurora kinase inhibitors, VX-680 and ZM-447439, in cultured TK6 cells using the micronucleus assay with CREST staining as well as a flow cytometry-based assay that measures multiple types of numerical chromosomal aberrations. The three compounds were highly effective in inducing aneuploidy and polyploidy as evidenced by increases in kinetochore-positive micronuclei, hyperdiploidy, and polyploidy. With fisetin, however, the latter two effects were most significantly observed only after cells were allowed to overcome a cell cycle delay, and occurred at higher concentrations than those induced by the other Aurora kinase inhibitors. Modest increases in kinetochore-negative micronuclei were also seen with the model Aurora kinase inhibitors. These results indicate that fisetin induces multiple types of chromosome abnormalities in human cells, and indicate a need for a thorough investigation of fisetin-augmented dietary supplements. PMID:24680981

  16. Shugoshin-1 balances Aurora B kinase activity via PP2A to promote chromosome bi-orientation

    NARCIS (Netherlands)

    Meppelink, Amanda; Kabeche, Lilian; Vromans, Martijn J M; Compton, Duane A; Lens, Susanne M A

    2015-01-01

    Correction of faulty kinetochore-microtubule attachments is essential for faithful chromosome segregation and dictated by the opposing activities of Aurora B kinase and PP1 and PP2A phosphatases. How kinase and phosphatase activities are appropriately balanced is less clear. Here, we show that a

  17. Irradiation of silver and agar/silver nanoparticles with argon, oxygen glow discharge plasma, and mercury lamp.

    Science.gov (United States)

    Ahmad, Mahmoud M; Abdel-Wahab, Essam A; El-Maaref, A A; Rawway, Mohammed; Shaaban, Essam R

    2014-01-01

    The irradiation effect of argon, oxygen glow discharge plasma, and mercury lamp on silver and agar/silver nanoparticle samples is studied. The irradiation time dependence of the synthesized silver and agar/silver nanoparticle absorption spectra and their antibacterial effect are studied and compared. In the agar/silver nanoparticle sample, as the irradiation time of argon glow discharge plasma or mercury lamp increases, the peak intensity and the full width at half maximum, FWHM, of the surface plasmon resonance absorption band is increased, however a decrease of the peak intensity with oxygen glow plasma has been observed. In the silver nanoparticle sample, as the irradiation time of argon, oxygen glow discharge plasma or mercury lamp increases, the peak intensity of the surface plasmon resonance absorption band is increased, however, there is no significant change in the FWHM of the surface plasmon resonance absorption band. The SEM results for both samples showed nanoparticle formation with mean size about 50 nm and 40 nm respectively. Throughout the irradiation time with the argon, oxygen glow discharge plasma or mercury lamp, the antibacterial activity of several kinds of Gram-positive and Gram-negative bacteria has been examined.

  18. Analytical Expressions for the Mixed-Order Kinetics Parameters of TL Glow Peaks Based on the two Heating Rates Method.

    Science.gov (United States)

    Maghrabi, Mufeed; Al-Abdullah, Tariq; Khattari, Ziad

    2018-03-24

    The two heating rates method (originally developed for first-order glow peaks) was used for the first time to evaluate the activation energy (E) from glow peaks obeying mixed-order (MO) kinetics. The derived expression for E has an insignificant additional term (on the scale of a few meV) when compared with the first-order case. Hence, the original expression for E using the two heating rates method can be used with excellent accuracy in the case of MO glow peaks. In addition, we derived a simple analytical expression for the MO parameter. The present procedure has the advantage that the MO parameter can now be evaluated using analytical expression instead of using the graphical representation between the geometrical factor and the MO parameter as given by the existing peak shape methods. The applicability of the derived expressions for real samples was demonstrated for the glow curve of Li 2 B 4 O 7 :Mn single crystal. The obtained parameters compare very well with those obtained by glow curve fitting and with the available published data.

  19. Boltzmann statistical consideration on the excitation mechanism of iron atomic lines emitted from glow discharge plasmas

    International Nuclear Information System (INIS)

    Zhang Lei; Kashiwakura, Shunsuke; Wagatsuma, Kazuaki

    2011-01-01

    A Boltzmann plot for many iron atomic lines having excitation energies of 3.3–6.9 eV was investigated in glow discharge plasmas when argon or neon was employed as the plasma gas. The plot did not show a linear relationship over a wide range of the excitation energy, but showed that the emission lines having higher excitation energies largely deviated from a normal Boltzmann distribution whereas those having low excitation energies (3.3–4.3 eV) well followed it. This result would be derived from an overpopulation among the corresponding energy levels. A probable reason for this is that excitations for the high-lying excited levels would be caused predominantly through a Penning-type collision with the metastable atom of argon or neon, followed by recombination with an electron and then stepwise de-excitations which can populate the excited energy levels just below the ionization limit of iron atom. The non-thermal excitation occurred more actively in the argon plasma rather than the neon plasma, because of a difference in the number density between the argon and the neon metastables. The Boltzmann plots yields important information on the reason why lots of Fe I lines assigned to high-lying excited levels can be emitted from glow discharge plasmas. - Highlights: ► This paper shows the excitation mechanism of Fe I lines from a glow discharge plasma. ► A Boltzmann distribution is studied among iron lines of various excitation levels. ► We find an overpopulation of the high-lying energy levels from the normal distribution. ► It is caused through Penning-type collision of iron atom with argon metastable atom.

  20. Boltzmann statistical consideration on the excitation mechanism of iron atomic lines emitted from glow discharge plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lei; Kashiwakura, Shunsuke; Wagatsuma, Kazuaki, E-mail: wagatuma@imr.tohoku.ac.jp

    2011-11-15

    A Boltzmann plot for many iron atomic lines having excitation energies of 3.3-6.9 eV was investigated in glow discharge plasmas when argon or neon was employed as the plasma gas. The plot did not show a linear relationship over a wide range of the excitation energy, but showed that the emission lines having higher excitation energies largely deviated from a normal Boltzmann distribution whereas those having low excitation energies (3.3-4.3 eV) well followed it. This result would be derived from an overpopulation among the corresponding energy levels. A probable reason for this is that excitations for the high-lying excited levels would be caused predominantly through a Penning-type collision with the metastable atom of argon or neon, followed by recombination with an electron and then stepwise de-excitations which can populate the excited energy levels just below the ionization limit of iron atom. The non-thermal excitation occurred more actively in the argon plasma rather than the neon plasma, because of a difference in the number density between the argon and the neon metastables. The Boltzmann plots yields important information on the reason why lots of Fe I lines assigned to high-lying excited levels can be emitted from glow discharge plasmas. - Highlights: Black-Right-Pointing-Pointer This paper shows the excitation mechanism of Fe I lines from a glow discharge plasma. Black-Right-Pointing-Pointer A Boltzmann distribution is studied among iron lines of various excitation levels. Black-Right-Pointing-Pointer We find an overpopulation of the high-lying energy levels from the normal distribution. Black-Right-Pointing-Pointer It is caused through Penning-type collision of iron atom with argon metastable atom.

  1. The impact of molecular emission in compositional depth profiling using Glow Discharge-Optical Emission Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bengtson, Arne [Corrosion and Metals Research Institute, Dr. Kristinas vaeg 48, Stockholm (Sweden)], E-mail: arne.bengtson@kimab.com

    2008-09-15

    The scope of this paper is to investigate and discuss how molecular emission can affect elemental analysis in glow discharge optical emission (GD-OES), particularly in compositional depth profiling (CDP) applications. Older work on molecular emission in glow discharges is briefly reviewed, and the nature of molecular emission spectra described. Work on the influence of hydrogen in the plasma, in particular elevated background due to a continuum spectrum, is discussed. More recent work from sputtering of polymers and other materials with a large content of light elements in a Grimm type source is reviewed, where substantial emission has been observed from several light diatomic molecules (CO, CH, OH, NH, C{sub 2}). It is discussed how the elevated backgrounds from such molecular emission can lead to significant analytical errors in the form of 'false' depth profile signals of several atomic analytical lines. Results from a recent investigation of molecular emission spectra from mixed gases in a Grimm type glow discharge are presented. An important observation is that dissociation and subsequent recombination processes occur, leading to formation of molecular species not present in the original plasma gas. Experimental work on depth profiling of a polymer coating and a thin silicate film, using a spectrometer equipped with channels for molecular emission lines, is presented. The results confirm that molecular emission gives rise to apparent depth profiles of elements not present in the sample. The possibilities to make adequate corrections for such molecular emission in CDP of organic coatings and very thin films are discussed.

  2. Application of Radio-Frequency Plasma Glow Discharge to Removal of Uranium Dioxide from Metal Surfaces

    International Nuclear Information System (INIS)

    El-Genk, Mohamed S.; Saber, Hamed H.

    2000-01-01

    Recent experiments have shown that radio-frequency (rf) plasma glow discharge using NF 3 gas is an effective technique for the removal of uranium oxide from metal surfaces. The results of these experiments are analyzed to explain the measured dependence of the UO 2 removal or etch rate on the NF 3 gas pressure and the absorbed power in the plasma. The NF 3 gas pressure in the experiments was varied from 10.8 to 40 Pa, and the deposited power in the plasma was varied from 25 to 210 W. The UO 2 etch rate was strongly dependent on the absorbed power and, to a lesser extent, on the NF 3 pressure and decreased exponentially with immersion time. At 210 W and 17 Pa, all detectable UO 2 in the samples (∼10.6 mg each) was removed at the endpoint, whereas the initial etch rate was ∼3.11 μm/min. When the absorbed power was ≤50 W, however, the etch rate was initially ∼0.5 μg/min and almost zero at the endpoint, with UO 2 only partially etched. This self-limiting etching of UO 2 at low power is attributed to the formation of nonvolatile intermediates UF 2 , UF 3 , UF 4 , UF 5 , UO 2 F, and UO 2 F 2 on the surface. Analysis indicated that the accumulation of UF 6 and, to a lesser extent, O 2 near the surface partially contributed to the exponential decrease in the UO 2 etch rate with immersion time. Unlike fluorination with F 2 gas, etching of UO 2 using rf glow discharge is possible below 663 K. The average etch rates of the amorphous UO 2 in the NF 3 experiments are comparable to the peak values reported in other studies for crystalline UO 2 using CF 4 /O 2 glow discharge performed at ∼150 to 250 K higher sample temperatures

  3. Breaking the Ice: Strategies for Future European Research in the Polar Oceans - The AURORA BOREALIS Concept

    Science.gov (United States)

    Lembke-Jene, L.; Biebow, N.; Wolff-Boenisch, B.; Thiede, J.; European Research Icebreaker Consortium

    2011-12-01

    Research vessels dedicated to work in polar ice-covered waters have only rarely been built. Their history began with Fritjof Nansen's FRAM, which he used for his famous first crossing of the Arctic Ocean 1893-1896. She served as example for the first generation of polar research vessels, at their time being modern instruments planned with foresight. Ice breaker technology has developed substantially since then. However, it took almost 80 years until this technical advance also reached polar research, when the Russian AKADEMIK FEDEROV, the German POLARSTERN, the Swedish ODEN and the USCG Cutter HEALY were built. All of these house modern laboratories, are ice-breakers capable to move into the deep-Arctic during the summer time and represent the second generation of dedicated polar research vessels. Still, the increasing demand in polar marine research capacities by societies that call for action to better understand climate change, especially in the high latitudes is not matched by adequate facilities and resources. Today, no icebreaker platform exists that is permanently available to the international science community for year-round expeditions into the central Arctic Ocean or heavily ice-infested waters of the polar Southern Ocean around Antarctica. The AURORA BOREALIS concept plans for a heavy research icebreaker, which will enable polar scientists around the world to launch international research expeditions into the central Arctic Ocean and the Antarctic continental shelf seas autonomously during all seasons of the year. The European Research Icebreaker Consortium - AURORA BOREALIS (ERICON-AB) was established in 2008 to plan the scientific, governance, financial, and legal frameworks needed for the construction and operation of this first multi-nationally owned and operated research icebreaker and polar scientific drilling platform. By collaborating together and sharing common infrastructures it is envisioned that European nations make a major contribution to

  4. Ozone Satellite Data Synergy and Combination with Non-satellite Data in the AURORA project

    Science.gov (United States)

    Cortesi, U.; Tirelli, C.; Arola, A.; Dragani, R.; Keppens, A.; Loenen, E.; Masini, A.; Tsiakos, , C.; van der A, R.; Verberne, K.

    2017-12-01

    The geostationary satellite constellation composed of TEMPO (North America), SENTINEL-4 (Europe) and GEMS (Asia) missions is a major instance of space component in the fundamentally new paradigm aimed at integrating information on air quality from a wide variety of sources. Space-borne data on tropospheric composition from new generation satellites have a growing impact in this context because of their unprecedented quantity and quality, while merging with non-satellite measurements and other types of auxiliary data via state-of-the-art modelling capabilities remains essential to fit the purpose of highly accurate information made readily available at high temporal and spatial resolution, both in analysis and forecast mode. Proper and effective implementation of this paradigm poses severe challenges to science, technology and applications that must be addressed in a closely interconnected manner to pave the way to high quality products and innovative services. Novel ideas and tools built on these three pillars are currently under investigation in the AURORA (Advanced Ultraviolet Radiation and Ozone Retrieval for Applications) Horizon 2020 project of the European Commission. The primary goal of the project is the proof of concept of a synergistic approach to the exploitation of Sentinel-4 and -5 Ozone measurements in the UV, Visible and Thermal Infrared based on the combination of an innovative data fusion method and assimilation models. The scientific objective shares the same level of priority with the technological effort to realize a prototype data processor capable to manage the full data processing chain and with the development of two downstream applications for demonstration purposes. The presentation offers a first insight in mid-term results of the project, which is mostly based on the use of synthetic data from the atmospheric Sentinels. Specific focus is given to the role of satellite data synergy in integrated systems for air quality monitoring, in

  5. Fra radikalt samfunnsportrett til borgerlig idyll? En resepsjonsanalyse av Anne-Cath. Vestlys forfatterskap med hovedvekt på Aurora-bøkene

    OpenAIRE

    Vatnedalen, Mariell Bugge

    2015-01-01

    I min avhandling gjennomgår jeg utviklingen og tendensene i resepsjonen til Anne-Cath. Vestlys forfatterskap fra samtiden og fram til i dag, med Aurora-serien til å eksemplifisere. Jeg støtter meg til bøkene om Aurora i blokk Z (1966) og Aurora og pappa (1967), som tar for seg en familie som bryter med de tradisjonelle kjønnsrollemønstrene. Far er hjemmeværende student, glad i husarbeid og passer barn. Mor på den annen side er jurist i jobb og kjører bil - alt de...

  6. Activation of Aurora A kinase through the FGF1/FGFR signaling axis sustains the stem cell characteristics of glioblastoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Yi-Chao [Division of Regenerative Medicine, Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan (China); Institute of Biomedical Sciences, Mackay Medical College, New Taipei City, Taiwan (China); Kao, Chien-Yu [Division of Regenerative Medicine, Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan (China); Graduate Program of Biotechnology in Medicine, Institute of Biotechnology and Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan (China); Chung, Yu-Fen; Lee, Don-Ching [Division of Regenerative Medicine, Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan (China); Liu, Jen-Wei [Division of Regenerative Medicine, Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan (China); Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan (China); Chiu, Ing-Ming, E-mail: ingming@nhri.org.tw [Division of Regenerative Medicine, Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan (China); Graduate Program of Biotechnology in Medicine, Institute of Biotechnology and Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan (China); Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan (China)

    2016-06-10

    Fibroblast growth factor 1 (FGF1) binds and activates FGF receptors, thereby regulating cell proliferation and neurogenesis. Human FGF1 gene 1B promoter (−540 to +31)-driven SV40 T antigen has been shown to result in tumorigenesis in the brains of transgenic mice. FGF1B promoter (−540 to +31)-driven green fluorescent protein (F1BGFP) has also been used in isolating neural stem cells (NSCs) with self-renewal and multipotency from developing and adult mouse brains. In this study, we provide six lines of evidence to demonstrate that FGF1/FGFR signaling is implicated in the expression of Aurora A (AurA) and the activation of its kinase domain (Thr288 phosphorylation) in the maintenance of glioblastoma (GBM) cells and NSCs. First, treatment of FGF1 increases AurA expression in human GBM cell lines. Second, using fluorescence-activated cell sorting, we observed that F1BGFP reporter facilitates the isolation of F1BGFP(+) GBM cells with higher expression levels of FGFR and AurA. Third, both FGFR inhibitor (SU5402) and AurA inhibitor (VX680) could down-regulate F1BGFP-dependent AurA activity. Fourth, inhibition of AurA activity by two different AurA inhibitors (VX680 and valproic acid) not only reduced neurosphere formation but also induced neuronal differentiation of F1BGFP(+) GBM cells. Fifth, flow cytometric analyses demonstrated that F1BGFP(+) GBM cells possessed different NSC cell surface markers. Finally, inhibition of AurA by VX680 reduced the neurosphere formation of different types of NSCs. Our results show that activation of AurA kinase through FGF1/FGFR signaling axis sustains the stem cell characteristics of GBM cells. Implications: This study identified a novel mechanism for the malignancy of GBM, which could be a potential therapeutic target for GBM. - Highlights: • We report that FGF1 treatment can stimulate AurA kinase expression in human GBM cells. • FGF1/FGFR signaling is involved in the activation of AurA kinase. • FGF1 sustains the self

  7. Activation of Aurora A kinase through the FGF1/FGFR signaling axis sustains the stem cell characteristics of glioblastoma cells

    International Nuclear Information System (INIS)

    Hsu, Yi-Chao; Kao, Chien-Yu; Chung, Yu-Fen; Lee, Don-Ching; Liu, Jen-Wei; Chiu, Ing-Ming

    2016-01-01

    Fibroblast growth factor 1 (FGF1) binds and activates FGF receptors, thereby regulating cell proliferation and neurogenesis. Human FGF1 gene 1B promoter (−540 to +31)-driven SV40 T antigen has been shown to result in tumorigenesis in the brains of transgenic mice. FGF1B promoter (−540 to +31)-driven green fluorescent protein (F1BGFP) has also been used in isolating neural stem cells (NSCs) with self-renewal and multipotency from developing and adult mouse brains. In this study, we provide six lines of evidence to demonstrate that FGF1/FGFR signaling is implicated in the expression of Aurora A (AurA) and the activation of its kinase domain (Thr288 phosphorylation) in the maintenance of glioblastoma (GBM) cells and NSCs. First, treatment of FGF1 increases AurA expression in human GBM cell lines. Second, using fluorescence-activated cell sorting, we observed that F1BGFP reporter facilitates the isolation of F1BGFP(+) GBM cells with higher expression levels of FGFR and AurA. Third, both FGFR inhibitor (SU5402) and AurA inhibitor (VX680) could down-regulate F1BGFP-dependent AurA activity. Fourth, inhibition of AurA activity by two different AurA inhibitors (VX680 and valproic acid) not only reduced neurosphere formation but also induced neuronal differentiation of F1BGFP(+) GBM cells. Fifth, flow cytometric analyses demonstrated that F1BGFP(+) GBM cells possessed different NSC cell surface markers. Finally, inhibition of AurA by VX680 reduced the neurosphere formation of different types of NSCs. Our results show that activation of AurA kinase through FGF1/FGFR signaling axis sustains the stem cell characteristics of GBM cells. Implications: This study identified a novel mechanism for the malignancy of GBM, which could be a potential therapeutic target for GBM. - Highlights: • We report that FGF1 treatment can stimulate AurA kinase expression in human GBM cells. • FGF1/FGFR signaling is involved in the activation of AurA kinase. • FGF1 sustains the self

  8. Two-dimensional electrodynamic structure of the normal glow discharge in an axial magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Surzhikov, S. T., E-mail: surg@ipmnet.ru [Russian Academy of Sciences, Institute for Problems in Mechanics (Russian Federation)

    2017-03-15

    Results are presented from numerical simulations of an axisymmetric normal glow discharge in molecular hydrogen and molecular nitrogen in an axial magnetic field. The charged particle densities and averaged azimuthal rotation velocities of electrons and ions are studied as functions of the gas pressure in the range of 1–5 Torr, electric field strength in the range of 100–600 V/cm, and magnetic field in the range of 0.01–0.3 T. It is found that the axial magnetic field does not disturb the normal current density law.

  9. Pulsed glow discharge mass spectrometry for molecular depth profiling of polymers

    International Nuclear Information System (INIS)

    Lobo, L.; Pereiro, R.; Sanz-Medel, A.; Bordel, N.; Pisonero, J.; Licciardello, A.; Tuccitto, N.; Tempez, A.; Chapon, P.

    2009-01-01

    Full text: Nowadays thin films of polymeric materials involve a wide range of industrial applications, so techniques capable of providing in-depth profile information are required. Most of the techniques available for this purpose are based on the use of energetic particle beams which interact with polymers producing undesirable physicochemical modifications. Radiofrequency pulsed glow discharge (rf-pulsed-GD) coupled to time-of-flight mass spectrometry (TOFMS) could afford the possibility of acquiring both elemental and molecular information creating minimal damage to surfaces and thereby obtaining depth profiles. This work will evaluate rf-GDs coupled to an orthogonal TOFMS for direct analysis of polymers. (author)

  10. Electron energy distribution function in a cathode fall region of DC-glow discharge

    International Nuclear Information System (INIS)

    Elakshar, F.F.; Garamoon, A.A.; Hassouba, M.A.

    1997-01-01

    Recently a substantial effort has been devoted towards the development of a quantitative microscopic measurements in the cathode fall region of the DC-glow discharge magnetron sputtering unit. The electron energy distribution function (EEDF) has been measured using a single Langmuir probe at the edge of the cathode fall. Two groups of electrons are observed in helium and argon gas discharges. The two groups have no chance to be thermalized since they leave the cathode fall region fast. The electron temperature measurements have been compared with spectroscopic determination. Plasma density has been computed and compared with probe measurements. Sources of the two groups of electrons are also discussed. (author)

  11. Stabilization of a cold cathode electron beam glow discharge for surface treatment

    International Nuclear Information System (INIS)

    Mingolo, N.; Gonzalez, C.R.; Martinez, O.E.; Rocca, J.J.

    1997-01-01

    We have demonstrated that the reproducibility of electron beam pulses generated by a high power, cold cathode glow discharge is greatly improved by adding a small continuous keep-alive discharge current. A current of the order of 200 μA was found to limit the shot to shot current variation to within 1.5%. This stabilization in turn reduces by an order of magnitude the fluctuations of the energy density deposited on the target, demonstrating a reliable energy source for surface treatment. copyright 1997 American Institute of Physics

  12. Nitridation Of The A A 2024 T3 Aluminium By The Glow Discharge Plasma Technique

    International Nuclear Information System (INIS)

    Mudjiman, Supardjono; Sujitno, Tjipto; Sudjatmoko

    1996-01-01

    Nitridation of A A 2024 T3 aluminium by means of plasma glow discharge technique has been carried out. For this purpose, the experiments were carried out at the temperature 30 o C, 60 o C, 100 o C, 150 o C, 200 o C, and 250 o C whereas the nitridation time were varied at 5 minutes, 15 minutes, 40 minutes, 90 minutes and 180 minutes. The results showed that the optimum temperature and time of nitridation were 60 o C and 90 minutes respectively and the hardness increased from 115 to 166 KHN

  13. Study on the characteristics of hysteresis loop and resistance of glow discharge plasma using argon gas

    Science.gov (United States)

    Mathew, Prijil; Sajith Mathews, T.; Kurian, P. J.; Chattopadyay, P. K.

    2018-05-01

    Hysteresis in discharge current is produced in a low-pressure, magnetic field free, Glow discharge plasma by varying discharge voltage. The variation in area of the hysteresis loops with pressure, electrode distance and load resistor studied. To understand, the nonlinear behaviour of the I-V characteristics, the changes in gas resistance with electrode voltage, pressure and load resistor were studied. After many trials we propose the best suitable empirical equation for the exponential decrease of the gas resistance with electrode voltage as; R = Rmin + Ae-0.008V, which is a novel one and matches well with our experimental results.

  14. Surface modification of austenitic steel by various glow-discharge nitriding methods

    Directory of Open Access Journals (Sweden)

    Tomasz Borowski

    2015-09-01

    Full Text Available Recent years have seen intensive research on modifying glow-discharge nitriding processes. One of the most commonly used glow-discharge methods includes cathodic potential nitriding (conventional method, and active screen plasma nitriding. Each of these methods has a number of advantages. One very important, common feature of these techniques is full control of the microstructure, chemical and phase composition, thickness and the surface topography of the layers formed. Another advantage includes the possibility of nitriding such materials as: austenitic steels or nickel alloys, i.e. metallic materials which do not diffuse nitrogen as effectively as ferritic or martensitic steels. However, these methods have some disadvantages as well. In the case of conventional plasma nitriding, engineers have to deal with the edge effect, which makes it difficult to use this method for complexly shaped components. In turn, in the case of active screen plasma nitriding, the problem disappears. A uniform, smooth layer forms, but is thinner, softer and is not as resistant to friction compared to layers formed using the conventional method. Research is also underway to combine these methods, i.e. use an active screen in conventional plasma nitriding at cathodic potential. However, there is a lack of comprehensive data presenting a comparison between these three nitriding processes and the impact of pulsating current on the formation of the microstructure and functional properties of austenitic steel surfaces. The article presents a characterisation of nitrided layers produced on austenitic X2CrNiMo17-12-2 (AISI 316L stainless steel in the course of glow-discharge nitriding at cathodic potential, at plasma potential and at cathodic potential incorporating an active screen. All processes were carried out at 440 °C under DC glow-discharge conditions and in 100 kHz frequency pulsating current. The layers were examined in terms of their microstructure, phase and

  15. Analysis of iron-base alloys by low-wattage glow discharge emission spectrometry

    International Nuclear Information System (INIS)

    Wagatsuma, K.; Hirokawa, K.

    1984-01-01

    Several iron-base alloys were investigated by low-wattage glow discharge emission spectrometry. The emission intensity principally depended on the sputtering parameters of constituent elements in the alloy. However, in the case of chromium, stable and firm oxides formed on the surface influencing the yield of ejected atoms. This paper discusses the relation between the sputtering parameters in Fe-Ni, Fe-Cr, and Fe-Co alloys and their relative emission intensities. Additionally, quantitative analysis was performed for some ternary iron-base alloys and commercial stainless steels with the calibration factors of binary alloy systems

  16. Variation of the Plasma Density in a Glow Discharge Upon the Application of A High Voltage

    International Nuclear Information System (INIS)

    Akman, S.

    2004-01-01

    It is emphasized and demonstrated that, during the formation of an ion-matrix sheath in a glow discharge upon the application of a high voltage pulse, the existing neutral plasma density should change as well. An explicit and practical expression for the neutral plasma density in terms of the gas pressure, secondary electron emission coefficient and the applied voltage is derived, so that the consequent sheath behavior can be formulated correctly. The theoretical result is compared with the data of an experiment, particularly designed and performed to test its validity, and found to be in good agreement with the latter

  17. Stabilization of a cold cathode electron beam glow discharge for surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Mingolo, N.; Gonzalez, C.R. [Lab. de Haces Dirigidos, Depto. de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Martinez, O.E. [Lab. de Electronica Cuantica, Depto. de Fisica, Universidad de Buenos Aires, Pabellon 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Rocca, J.J. [Department of Electrical Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States)

    1997-10-01

    We have demonstrated that the reproducibility of electron beam pulses generated by a high power, cold cathode glow discharge is greatly improved by adding a small continuous keep-alive discharge current. A current of the order of 200 {mu}A was found to limit the shot to shot current variation to within 1.5{percent}. This stabilization in turn reduces by an order of magnitude the fluctuations of the energy density deposited on the target, demonstrating a reliable energy source for surface treatment. {copyright} {ital 1997 American Institute of Physics.}

  18. A simple theoretical approach to determine relative ion yield (RIY) in glow discharge mass spectrometry (GDMS)

    Energy Technology Data Exchange (ETDEWEB)

    Born, Sabine [Degussa AG, Hanau (Germany); Matsunami, Noriaki [Nagoya Univ. (Japan). Faculty of Engineering; Tawara, Hiroyuki [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2000-01-01

    Direct current glow discharge mass spectrometry (dc-GDMS) has been applied to detect impurities in metals. The aim of this study is to understand quantitatively the processes taking place in GDMS and establish a model to calculate the relative ion yield (RIY), which is inversely proportional to the relative sensitivity factor (RSF), in order to achieve better agreement between the calculated and the experimental RIYs. A comparison is made between the calculated RIY of the present model and the experimental RIY, and also with other models. (author)

  19. Child–Langmuir law applicability for a cathode sheath description of glow discharge in hydrogen

    International Nuclear Information System (INIS)

    Lisovskiy, V A; Artushenko, K P; Yegorenkov, V D

    2016-01-01

    The present paper reveals that the Child-Langmuir law version with the constant ion mobility has to be applied for the cathode sheath description of the glow discharge in hydrogen. Using the analytical model we demonstrate that even in a high electric field the constant mobility law version rather than that for the constant ion mean free path has to hold in the case of impeded charge exchange and the dominant effect of polarization forces on the ion motion through the cathode sheath. (paper)

  20. Study of stability of dc glow discharges with the use of Comsol Multiphysics software

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, P G C; Benilov, M S; Faria, M J [Departamento de Fisica, Universidade da Madeira, Largo do Municipio, 9000 Funchal (Portugal)

    2011-10-19

    Stability of different axially symmetric modes of current transfer in dc glow discharges is investigated in the framework of the linear stability theory with the use of Comsol Multiphysics software. Conditions of current-controlled microdischarges in xenon are treated as an example. Both real and complex eigenvalues have been detected, meaning that perturbations can vary with time both monotonically and with oscillations. In general, results given by the linear stability theory confirm intuitive concepts developed in the literature and conform to the experiment. On the other hand, suggestions are provided for further experimental and theoretical work.

  1. Construction of automatic photographic system for after-glow colour images (AGCI)

    International Nuclear Information System (INIS)

    Kawamura, Kousei; Hashimoto, Tetsuo.

    1995-01-01

    An automatic photographic system of the after-glow colour images (AGCI), which give very useful information related to crystal defects and impurities in white inorganic materials, has been developed. The present system consists of a combination of a photographic part installed in a dark bag with a control personal computer through an interface board. Thus, the photographic procedure of the successive and clear AGCIs could be accomplished from the direct contact of a colour film with an X-rays irradiated rock slices for desired exposure periods and interval times. By using this system, some AGCIs of ammonite fossil showed interesting changes of orange patterns due to structural fossil calcite. (author)

  2. Plasma actuators for active flow control based on a glow discharge

    International Nuclear Information System (INIS)

    Kühn, M.; Kühn-Kauffeldt, M.; Schein, J.; Belinger, A.

    2017-01-01

    In this work a glow discharge based active flow control for high flow velocities and low Reynolds numbers is presented. Unlike common plasma actuators such as dielectric barrier discharge (DBD) or spark jets, this actuator uses small impulse bits at frequencies. The actuator is optimized for frequencies up to 40 kHz to counter Tollmien Schlichting wave effects and so reduce overall air foil drag. Several measurements to prove the non-eroding effect of the actuator and the electrical properties were performed. It was found that the actuator is capable of operating at high frequencies without measurable erosion. (paper)

  3. Dynamics of excited nitrogen molecular states in glow- and afterglow phases of discharge: experiment and modeling

    International Nuclear Information System (INIS)

    Napartovich, A.P.; Akishev, Yu.S.; Dyatko, N.A.; Grushin, M.E.; Filippov, A.V.; Trushkin, N.I.

    2001-01-01

    Population dynamics for a number of levels from N2 ( A 3 Σ + u ), N 2 (B 3 Π g ) and N 2 (C 3 Π u ) manifolds was studied spectroscopically in a long pulse glow discharge in pure nitrogen and in afterglow at pressure 50 Torr. Overshot in time behaviour of N 2 (A 3Σ + u ), N 2 (B 3 Π g ) and N 2 (C 3 Π u ) levels populations was revealed. A rather complete kinetic model is developed for conditions of the experiments. Results of comparison are analyzed

  4. Sputtering in a glow discharge ion source - pressure dependence: theory and experiment

    International Nuclear Information System (INIS)

    Mason, R.S.; Pichilingi, Melanie

    1994-01-01

    A simplified theoretical expression has been developed for a glow discharge to show how the average cathode erosion rate (expressed as the number of atoms per ion of the total bombarding flux) varies with primary sputter yield, pressure, 'diffusion length' and sputtered atom 'stopping' cross section. An inverse pressure dependence is predicted which correlates well with experiment in the 2 and He, tend to converge. It is suggested that this could be due to a change in the mechanism to self-sputtering. Under constant conditions, the erosion rates of different cathode materials still correlate quite well with the differences in their primary sputter yields. (author)

  5. Investigation of plasma potential and pulsed discharge characteristics in enhanced glow discharge plasma immersion ion implantation and deposition

    International Nuclear Information System (INIS)

    Li Liuhe; Lu Qiuyuan; Fu, Ricky K.Y.; Chu, Paul K.

    2009-01-01

    Enhanced glow discharge plasma immersion ion implantation and deposition (EGD-PII and D) does not require external plasma sources. In this technique, the plasma is produced by self-glow discharge when a high negative voltage is applied to the sample. The small-area, pointed-shape hollow anode and large area tabular cathode form an electron-focused electric field. Using a special electric field design, the electrons from either the plasma or target (secondary electrons) are focused to a special hollow anode. As a result of the special electron-focusing field, the self-glow discharge process can be enhanced to achieve effective ion implantation into the substrate. In this work, the plasma potential distribution is investigated in details and the possible pulse discharge mechanism is discussed. The unique characteristics of the pulsed plasma and plasma extinction are studied.

  6. Investigation of the characteristics of thermoluminescence glow curves of natural hydrothermal quartz from Hakkari area in Turkey

    International Nuclear Information System (INIS)

    Topaksu, M.; Yüksel, M.; Dogan, T.; Nur, N.; Akkaya, R.; Yegingil, Z.; Topak, Y.

    2013-01-01

    In this study the dosimetric characteristics of some natural hydrothermal quartz (NHQ) samples collected from Hakkari were investigated by using the thermoluminescence (TL) technique for the purpose of determining whether they are suitable as dosimetric materials or not and calculating the kinetic parameters. The experiments carried out can be outlined as: analyzing TL glow curves of NHQ; determining the annealing conditions; the effects of pre-irradiation annealing procedures on TL sensitivity; the investigation of the characteristics of TL glow curves obtained after annealing the samples; determination of the trap parameters with the computerized glow curve deconvolution (CGCD) method and the peak shape (PS) method. The obtained results showed that the trap depths and the frequency factor values are consistent with the literature. The studied samples have linear dose responses for the absorbed doses ranging between ∼6.689 Gy and ∼301 Gy. In conclusion, the examined quartz samples can be used as dosimetric materials in high dose applications

  7. On the analysis of glow curves with the general order kinetics: Reliability of the computed trap parameters

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, F. [Facultad de Ingeniería (UNCPBA) and CIFICEN (UNCPBA – CICPBA – CONICET), Av. del Valle 5737, 7400 Olavarría (Argentina); Santiago, M.; Martinez, N.; Marcazzó, J.; Molina, P.; Caselli, E. [Instituto de Física Arroyo Seco (UNCPBA) and CIFICEN (UNCPBA – CICPBA – CONICET), Pinto 399, 7000 Tandil (Argentina)

    2017-04-15

    Nowadays the most employed kinetics for analyzing glow curves is the general order kinetics (GO) proposed by C. E. May and J. A. Partridge. As shown in many articles this kinetics might yield wrong parameters characterizing trap and recombination centers. In this article this kinetics is compared with the modified general order kinetics put forward by M. S. Rasheedy by analyzing synthetic glow curves. The results show that the modified kinetics gives parameters, which are more accurate than that yield by the original general order kinetics. A criterion is reported to evaluate the accuracy of the trap parameters found by deconvolving glow curves. This criterion was employed to assess the reliability of the trap parameters of the YVO{sub 4}: Eu{sup 3+} compounds.

  8. Aurora project: optical design for a kilojoule class KrF laser

    International Nuclear Information System (INIS)

    Hanlon, J.; McLeod, J.; Sollid, J.E.; Horn, W. III; Carmichael, R.; Kortegaard, B.; Woodfin, G.; Rosocha, L.

    1985-01-01

    Aurora is a 248-nm, 10-kilojoule laser system being built at Los Alamos National Laboratory to demonstrate the feasibility of large KrF laser systems for laser fusion. It was designed as a test bed to demonstrate: (1) efficiet energy extraction at 248 nm; (2) an angularly multiplexed optical system that is scaleable to large system designs; (3) the control of parasitics and ASE (amplified spontaneous emission); (4) long path pulse propagation at uv wavelengths; (5) alignment systems for multibeam systems; and (6) new or novel approaches to optical hardware that can lead to cost reduction on large systems. In this paper only issues pertinent to the optical system are addressed. First, a description of the entire system is given. The design constraints on the optical system are explained, concurrent with a discussion of the final design. This is followed by a very brief discussion of coatings; in particular, the use of sol-gels for antireflection coatings is presented

  9. Plant Aurora kinases play a role in maintenance of primary meristems and control of endoreduplication

    Czech Academy of Sciences Publication Activity Database

    Petrovská, Beáta; Cenklová, Věra; Pochylová, Žaneta; Kourová, Hana; Doskočilová, Anna; Plíhal, Ondřej; Binarová, Lenka; Binarová, Pavla

    2012-01-01

    Roč. 193, č. 3 (2012), s. 590-604 ISSN 0028-646X R&D Projects: GA ČR(CZ) GA204/07/1169; GA ČR GP204/09/P155; GA ČR(CZ) GD204/09/H084; GA MŠk(CZ) LC06034; GA MŠk LC545; GA AV ČR IAA500200719 Grant - others:GA MŠk(CZ) ED0007/01/01 Program:ED Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z50200510 Keywords : Arabidopsis thaliana * AtTPX2 (targeting protein for Xklp2) * Aurora kinases Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.736, year: 2012

  10. GPS Signal Corruption by the Discrete Aurora: Precise Measurements From the Mahali Experiment

    Science.gov (United States)

    Semeter, Joshua; Mrak, Sebastijan; Hirsch, Michael; Swoboda, John; Akbari, Hassan; Starr, Gregory; Hampton, Don; Erickson, Philip; Lind, Frank; Coster, Anthea; Pankratius, Victor

    2017-10-01

    Measurements from a dense network of GPS receivers have been used to clarify the relationship between substorm auroras and GPS signal corruption as manifested by loss of lock on the received signal. A network of nine receivers was deployed along roadways near the Poker Flat Research Range in central Alaska, with receiver spacing between 15 and 30 km. Instances of large-amplitude phase fluctuations and signal loss of lock were registered in space and time with auroral forms associated with a sequence of westward traveling surges associated with a substorm onset over central Canada. The following conclusions were obtained: (1) The signal corruption originated in the ionospheric E region, between 100 and 150 km altitude, and (2) the GPS links suffering loss of lock were confined to a narrow band (<20 km wide) along the trailing edge of the moving auroral forms. The results are discussed in the context of mechanisms typically cited to account for GPS phase scintillation by auroral processes.

  11. Our life is protected by the Earth's atmosphere and magnetic field: what aurora research tells us.

    Science.gov (United States)

    Kamide, Y

    2001-01-01

    Our sun is an average middle-aged star. Without the sun, there would be no atmosphere, no water, and no life on the Earth. The sun is constantly changing, providing the Earth with energy through a complicated chain of processes that occur in space surrounding the Earth. This paper demonstrates that life on Earth is protected by two barriers, i.e., the atmosphere and the magnetic field, against otherwise menacing events in space. Because of these shielding effects, we, peacefully sitting on the Earth's surface, are not aware of a number of critical and potentially dangerous episodes that are taking place only 100 km above the Earth's surface. The aurora, which dances in the polar sky also because of the two barriers, is sending us a crucial hint about what is happening in space.

  12. Baseline vegetation inventory and productivity assessment for the Syncrude Aurora Mine EIA local study area

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    This report presented an inventory and assessment of vegetation communities and forest covers within the proposed Aurora Mine local study area. A field inventory was conducted in the summer of 1995 to ground-truth air photo interpretations and to collect data. The inventory includes a classification of vegetation, forest covers and wetlands. It also includes the documentation of uncommon plants and the vegetation productivity estimates of tree, shrub and herbaceous plants. The study area is located east of the Athabasca River about 35 km northeast of Mildred Lake Oil Sands Plant. The area includes portions of Oil Sands Leases 10, 12, 13, 31, and 34 which includes much of the Muskeg River drainage and all of Kearl Lake. 24 refs., 7 tabs., 3 figs.

  13. Coordinated observations of electron energy spectra and electrostatic cyclotron waves during diffuse auroras

    International Nuclear Information System (INIS)

    Fontaine, D.; Perraut, S.; Cornilleau-Wehrlin, N.; Aparicio, B.; Bosqued, J.M.; Rodgers, D.

    1986-01-01

    An auroral precipitation event lasting several hours in the dusk sector on June 2, 1982 is studied in conjunction with three instruments: the EISCAT European Incoherent Scatter radar based in Scandinavia, the GEOS-2 European geostationary spacecraft, and the ARCAD-3 French-Soviet polar spacecraft. Electron energy spectra between about 1 and 10 keV, computed from EISCAT measurements, were in agreement, during a diffuse aurora period, with direct observations onboard ARCAD-3, and also with the plasma sheet component (3-10 keV) measured onboard GEOS-2 and available at large pitch-angles. This last comparison suggested the quasi-isotropy of equatorial electron fluxes. The electrostatic electron cyclotron harmonic waves, also observed onboard GEOS-2, were not found to be intense enough to cause by themselves the strong pitch-angle diffusion of electrons of a few keV

  14. On the physical processes ruling an atmospheric pressure air glow discharge operating in an intermediate current regime

    International Nuclear Information System (INIS)

    Prevosto, L.; Mancinelli, B.; Chamorro, J. C.; Cejas, E.; Kelly, H.

    2015-01-01

    Low-frequency (100 Hz), intermediate-current (50 to 200 mA) glow discharges were experimentally investigated in atmospheric pressure air between blunt copper electrodes. Voltage–current characteristics and images of the discharge for different inter-electrode distances are reported. A cathode-fall voltage close to 360 V and a current density at the cathode surface of about 11 A/cm 2 , both independent of the discharge current, were found. The visible emissive structure of the discharge resembles to that of a typical low-pressure glow, thus suggesting a glow-like electric field distribution in the discharge. A kinetic model for the discharge ionization processes is also presented with the aim of identifying the main physical processes ruling the discharge behavior. The numerical results indicate the presence of a non-equilibrium plasma with rather high gas temperature (above 4000 K) leading to the production of components such as NO, O, and N which are usually absent in low-current glows. Hence, the ionization by electron-impact is replaced by associative ionization, which is independent of the reduced electric field. This leads to a negative current-voltage characteristic curve, in spite of the glow-like features of the discharge. On the other hand, several estimations show that the discharge seems to be stabilized by heat conduction; being thermally stable due to its reduced size. All the quoted results indicate that although this discharge regime might be considered to be close to an arc, it is still a glow discharge as demonstrated by its overall properties, supported also by the presence of thermal non-equilibrium

  15. Pitch angle scattering and particle precipitation in a pulsating aurora - an experimental study

    International Nuclear Information System (INIS)

    Sandahl, I.

    1984-10-01

    A pulsating aurora occurring during the recovery phase of a substorm on January 27, 1979 was monitored by a large set of instruments. The Swedish sounding rocket S23-L2 was launched at magnetic midnight over pulsating patches, some of which exhibited 3+-1 Hz modulation. The ground based instrumentation included auroral TV cameras, all sky cameras, photometers and magnetometers. The geostationary satellite GEOS-2 was located in the equatorial plane, approximately conjugate to the rocket. The central experiment of this study is the particle experiment on the rocket. Several aspects of pulsating auroras have been investigated. The auroral luminosity variations were very well correlated to variations in the flux of precipitating hot electrons. The 1-20 second pulsations were caused by increased fluxes of 4-40 keV electrons. The 3+-1 Hz modulation was detected in 7-200 keV electrons, but the biggest energy flux modulation occurred for electrons of about 60 keV. Model calculations involving the electron distributions measured by the sounding rocket and GEOS-2, consistently show that the electrons may have been scattered into the loss cone through the Doppler shifted gyroresonance with whistler mode waves. The scattering was not a pure pitch angle scattering as in the classical Coroniti and Kennel theory, but involved also a systematic energy loss from the particles. The waves were probably hiss with some chorus elements. The equatorial plane plasma density was estimated in two independent ways to be about 2x10 6 m- 3 . The 3+-1 Hz modulation was measured both by the particle experiment on the rocket and by the wave experiment on GEOS-2. Properties of the modulated fluxes are described and a qualitative model for the cause of the modulation is proposed. (author)

  16. Dayside aurorae and polar arcs under south-east IMF orientation

    Directory of Open Access Journals (Sweden)

    P. E. Sandholt

    2006-12-01

    Full Text Available We document a characteristic spatial and temporal structure of the aurora in the postnoon sector present during a 10-h-long interval of very steady southeast IMF orientation (clock angle=135° ending in a sharp south-to-north transition. Focus is placed on the detailed morphology of auroral forms/activities corresponding to merging and lobe convection cells obtained from SuperDARN convection data and Greenland magnetograms. The ground optical instruments at Ny Ålesund, Svalbard (76° MLAT recorded different auroral forms/activities as the station moved to higher magnetic local times (MLTs in the 13:00–17:00 MLT sector. Whereas the 13:00–15:00 MLT sector is characterized by classical poleward moving auroral forms (PMAFs associated with merging cell transients, the aurora in the 15:00–17:00 MLT sector shows instead a characteristic latitudinal bifurcation consisting of standard oval forms and polar arcs, and a corresponding composite pattern of merging and lobe convection cells. The merging and lobe cells respond to the southward and northward IMF transitions by activation/fading and fading/activation, respectively. A sequence of brightening events is characterized by successive activations progressing in latitude from the merging cell regime to the lobe cell regime. Emphasis is placed on the association between polar arc brightenings and the activation of the channel of enhanced sunward flow in the lobe cell. The observations are discussed in relation to recent work on solar wind-magnetosphere-ionosphere interconnection topology.

  17. New benzimidazoles and their antitumor effects with Aurora A kinase and KSP inhibitory activities.

    Science.gov (United States)

    Abd El-All, Amira S; Magd-El-Din, Asmaa A; Ragab, Fatma A F; ElHefnawi, Mahmoud; Abdalla, Mohamed M; Galal, Shadia A; El-Rashedy, Ahmed A

    2015-07-01

    A newly synthesized series of anticancer compounds comprising thiazolo[3,2-a]pyrimidine derivatives 6a-q bearing a benzimidazole moiety was produced via a one-pot reaction of N-(4-(1H-benzo[d]imidazol-2-yl)phenyl)-2-cyanoacetamide 5 with 2-aminothiazole and an appropriate aromatic aldehyde. Compound 7 was obtained via the reaction of 4-(1H-benzo[d]imidazol-2yl)benzenamide 1 with carbon disulphide and methyl iodide in the presence of concentrated aqueous solution of NaOH, then treated with o-phenylenediamine to give N-(4-1H-benzo[d]imidazol-2-yl)phenyl)-1H-benzo[d]imidazol-2-amine 8. The structures of the newly synthesized compounds were confirmed by analytical and spectroscopic measurements (IR, MS, and (1) H NMR). The synthesized products were screened and studied for their in vitro antitumor activity against three human cancer cell lines (namely colorectal cancer cell line HCT116, human liver cancer cell line HepG2, and human ovarian cancer cell line A2780) and their Aurora A kinase and KSP inhibitory activities. All newly synthesized compounds revealed marked results comparable with the standard drug CK0106023. The compounds 6e and 6k of the thiazolopyrimidine derivatives were the most active compounds when tested against the three cell lines in comparison with the standard drug CK0106023, and showed potent dual KSP and Aurora A kinase inhibition. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Anticipated Guilt for not Helping and Anticipated Warm Glow for Helping are Differently Impacted by Personal Responsibility to Help

    Directory of Open Access Journals (Sweden)

    Arvid Erlandsson

    2016-09-01

    Full Text Available One important motivation for people behaving prosocially is that they want to avoid negative and obtain positive emotions. In the prosocial behavior literature however, the motivations to avoid negative emotions (e.g. guilt and to approach positive emotions (e.g. warm glow are rarely separated, and sometimes even aggregated into a single mood-management construct. The aim of this study was to investigate whether anticipated guilt if not helping and anticipated warm glow if helping are influenced similarly or differently when varying situational factors related to personal responsibility to help. Helping scenarios were created and pilot tests established that each helping scenario could be formulated both in a high-responsibility version and in a low-responsibility version. In Study 1 participants read high-responsibility and low-responsibility helping scenarios, and rated either their anticipated guilt if not helping or their anticipated warm glow if helping (i.e. separate evaluation. Study 2 was similar but here participants rated both their anticipated guilt if not helping and their anticipated warm glow if helping (i.e. joint evaluation. Anticipated guilt was clearly higher in the high-responsibility versions, but anticipated warm glow was unaffected (in Studies 1a and 1b, or even higher in the low-responsibility versions (Study 2. In Studies 3 (where anticipated guilt and warm glow were evaluated separately and 4 (where they were evaluated jointly, personal responsibility to help was manipulated within-subjects. Anticipated guilt was again constantly higher in the high-responsibility versions but for many types of responsibility-manipulations, anticipated warm glow was higher in the low-responsibility versions. The results suggest that we anticipate guilt if not fulfilling our responsibility but that we anticipate warm glow primarily when doing over and beyond our responsibility. We argue that future studies investigating motivations for

  19. Visualizing ignition and combustion of methanol mixtures in a diesel engine; Methanol funmu no glow chakka to nensho no kashika

    Energy Technology Data Exchange (ETDEWEB)

    Inomoto, Y; Harada, T; Kusaka, J; Daisho, Y; Kihara, R; Saito, T [Waseda University, Tokyo (Japan)

    1997-10-01

    A glow-assisted ignition system tends to suffer from poor ignitability and slow flame propagation at low load in a direct-injection diesel engine fueled with methanol. To investigate the ignition process and improve such disadvantages, methanol sprays, their ignition and flames were visualized at high pressures and temperatures using a modified two-stroke engine. The results show that parameters influencing ignition, the location of a glow-plug, swirl level, pressure and temperature are important. In addition, a full kinetics calculation was conducted to predict the delay of methanol mixture ignition by taking into account 39 chemical species and 157 elementary reactions. 3 refs., 9 figs.

  20. Glow discharge, its sensitivity to infra-red radiation. Observations made during the testing of multiwire proportional chambers

    International Nuclear Information System (INIS)

    Marsh, J.B.; Souten, K.H.; O'Hagan, B.

    1979-05-01

    It has been shown that under glow discharge conditions, multiwire proportional chambers are sensitive to infra-red radiation. Discharge current measurements and light change measurements have been made and the effect of the input window on the output signal and the importance of the finish of the anode and HT wires have been investigated. From these observations it would appear that a glow discharge in the form detailed in this report is sensitive to infra-red radiation though work is still required to optimise the parameters of such a device for IR detection or solar cell technology. (UK)

  1. An influence of ion and sputtered atom flows inhomogeneity on time evolution of the target surface relief in glow discharge

    International Nuclear Information System (INIS)

    Bondarenko, G G; Kristya, V I

    2008-01-01

    A mathematical model of ion and sputtered atom transport in the vicinity of the target with a periodical surface relief in glow discharge in pure gas is developed. Under the assumption that the relief amplitude is small, analytical expressions for their flows are found by the perturbation method and an equation describing the relief amplitude time evolution is derived. It is shown that intensity of sputtering exceeds intensity of sputtered material re-deposition at the relief tops, and relief smoothing always takes place in the process of homogeneous target treatment in glow discharge in pure gas

  2. The hydrogen and oxygen content of self-supporting carbon foils prepared by dc glow discharge in ethylene

    International Nuclear Information System (INIS)

    Tait, N.R.S.; Tolfree, D.W.L.; John, P.; Odeh, I.M.; Thomas, M.J.K.; Tricker, M.J.; Wilson, J.J.B.; England, J.B.A.; Newton, D.

    1980-01-01

    The hydrogen and oxygen content of self-supporting carbon films produced by dc glow discharge have been determined using a precise method involving the elastic scattering of 25 MeV α-particles. The number of carbon-hydrogen bonds has been determined for similar samples using infrared spectroscopy. The results are compared with those for samples made by the carbon arc process. Assuming that the glow discharge carbon contains graphitic regions surrounded by amorphous tetrahedrally bonded material to which hydrogen can attach, a simple estimate is made of the relative numbers of carbon atoms in the two forms. (orig.)

  3. Glow discharge optical emission spectroscopy for accurate and well resolved analysis of coatings and thin films

    KAUST Repository

    Wilke, Marcus

    2011-12-01

    In the last years, glow discharge optical emission spectrometry (GDOES) gained more and more acceptance in the analysis of functional coatings. GDOES thereby represents an interesting alternative to common depth profiling techniques like AES and SIMS, based on its unique combination of high erosion rates and erosion depths, sensitivity, analysis of nonconductive layers and easy quantification even for light elements such as C, N, O and H. Starting with the fundamentals of GDOES, a short overview on new developments in instrument design for accurate and well resolved thin film analyses is presented. The article focuses on the analytical capabilities of glow discharge optical emission spectrometry in the analysis of metallic coatings and thin films. Results illustrating the high depth resolution, confirmation of stoichiometry, the detection of light elements in coatings as well as contamination on the surface or interfaces will be demonstrated by measurements of: a multilayer system Cr/Ti on silicon, interface contamination on silicon during deposition of aluminum, Al2O3-nanoparticle containing conversion coatings on zinc for corrosion resistance, Ti3SiC2 MAX-phase coatings by pulsed laser deposition and hydrogen detection in a V/Fe multilayer system. The selected examples illustrate that GDOES can be successfully adopted as an analytical tool in the development of new materials and coatings. A discussion of the results as well as of the limitations of GDOES is presented. © 2011 Elsevier B.V.

  4. Electronic perturbation investigations into excitation and ionization in the millisecond pulsed glow discharge plasma

    International Nuclear Information System (INIS)

    Li Lei; Robertson-Honecker, Jennifer; Vaghela, Vishal; King, Fred L.

    2006-01-01

    This study employed a power perturbation method to examine the energy transfer processes at different locations within the afterpeak regime of a millisecond pulsed glow discharge plasma. Brief power perturbation pulses were applied during the afterpeak regime altering the environment of the collapsing plasma. Responses of several transitions to the power perturbations were measured via atomic emission and absorption spectroscopic methods at various distances from the surface of the cathode. The experimental data provide further insight into the energy transfer processes that occur at different spatial locations and in different temporal regimes of these pulsed glow discharge plasmas. Although the enhancement of the large population of metastable argon atoms is again confirmed, the mechanism responsible for this enhancement remains unclear. The most likely possibility involves some form of ion-electron recombination followed by radiative relaxation of the resulting species. The metastable argon atoms subsequently Penning ionize sputtered copper atoms which then appear to undergo a similar ion-electron recombination process yielding variable degrees of observable afterpeak emission for copper atom transitions. The kinetic information of these processes was approximated from the corresponding relaxation time. The electron thermalization time allowing for recombination with ions was found to be ∼25 μs after the discharge power termination

  5. Cleaning and conditioning of the walls of plasma devices by glow discharges in hydrogen

    International Nuclear Information System (INIS)

    Waelbroeck, F.; Winter, J.; Ali-Khan, I.; Wienhold, P.; Dietz, K.J.

    1980-12-01

    The influence of a number of parameters on the cleaning and preconditioning efficiency of a combined rf and glow (RG) discharge is studied experimentally. The emphasis is laid on problems of oxygen removal from the surface. The important parameters are the wall temperature Tsub(W), the pump speed SP, the current Isub(G)D of the glow discharge and the hydrogen pressure P 2 . In a device with a ratio SP/S = 0,1 ms -1 (S: inner area), a rapid deoxidation is achieved when T-W >= 200 0 C. At room temperature, the oxide layer is reduced from a (carbon-free) surface when 1 to 2% of methane is added to the hydrogen: carbon monoxide is formed and evacuated. Admixture of other gases such as He, Ne do not increase the cleaning efficiency. An equation derived from a simplified model describes semi-quantitatively the observed parametric dependances. The tendency for arc spots to occur during the initial phases of the discharge depends on the preconditioning of the wall: a prolonged bake-out at 200 0 C leads to the non-appearance of arcs in all cases examined. Problems arise when a quadrupole residual gas analyser is used to measure the partial pressure of water in hydrogen. These are analysed and a conditioning technique is described which has proven to be appropriate in our measurements. (orig.)

  6. Re-design of ITER Glow Discharge Cleaning system based on a fixed electrode concept

    International Nuclear Information System (INIS)

    Yang, Y.; Maruyama, S.; Kiss, G.; O’Connor, M.; Zhang, Y.; Pitts, R.A.; Shimada, M.; Fang, T.; Wang, Y.; Wang, M.; Pan, Y.; Li, B.; Li, L.

    2014-01-01

    Highlights: •This paper summarizes the approved new design of ITER GDC. •It is based on the fixed electrode design instead of the previous movable concept. •Estimates were made on the glow current density. •R and D topics on initiation, steady state and heat load were presented. •Other relevant considerations were listed in an exhaustive manner. -- Abstract: A new design of ITER Glow Discharge Cleaning (GDC) system based on a fixed electrode concept replaces the previous design which was based on a movable electrode integrated with the ITER In-Vessel-Viewing-System. Recently the conceptual design of the GDC system was reviewed successfully on the functions, safety, operation and maintenance. The design proposed was checked against the requirements and found to be feasible. This paper gives an overall description of the requirements from physics and operation viewpoints and introduces the design at the conceptual level. Main R and D activities are listed and summarized. Further detailed studies are to be performed in the following design stage

  7. Bidimensional characterization of the emission spectra in a direct current atmospheric pressure glow discharge

    International Nuclear Information System (INIS)

    Orejas, Jaime; Pisonero, Jorge; Bordel, Nerea; Nelis, Thomas; Guillot, Philippe; Sanz-Medel, Alfredo

    2012-01-01

    An in-house atmospheric pressure glow discharge source, designed to be used as ionization/desorption source for ambient mass spectrometry, has been electrically characterized, and its optical emission spectra evaluated in detail. Electrical characterization showed that the plasma regime can vary from glow discharge to arc discharge depending on operating conditions (i.e. He flow rate and inter electrode distance). Furthermore, bidimensional images of the optical emission of some plasma species using filters as wavelength selectors, were registered from inside and outside the discharge chamber (inner region and afterglow region respectively), showing the spatial distribution of excited species (i.e. He*, N 2 + and O*). These distribution patterns are useful to study the chemistry of the discharge plasma, since different production pathways and different excitation energies affect the presence of these species in the plasma regions. - Highlights: ► An in-house APGD is characterized through electrical and OES measurements. ► Interelectrode distance had more effect on electric regime than He flow rate. ► Internal plume images showed differences on the production pathways for each species. ► Higher interelectrode distances and He flow rates showed better afterglow conditions.

  8. Transmission characteristics of microwave in a glow-discharge dusty plasma

    Science.gov (United States)

    Jia, Jieshu; Yuan, Chengxun; Gao, Ruilin; Liu, Sha; Yue, Feng; Wang, Ying; Zhou, Zhong-Xiang; Wu, Jian; Li, Hui

    2016-07-01

    In this study, the propagation characteristics of electromagnetic wave in a glow discharge plasma with dust particles are experimentally investigated. A helium alternating current glow discharge plasmas have been successfully generated. Measurements of the plasma parameters using Langmuir probes, in the absence of dust particles, provide plasma densities (ne) of 1017 m-3 and electron temperatures (Te) ranging from 2 to 4 eV. Dusty plasmas are made by adding 30 nm radius aluminum oxide (Al2O3) particles into the helium plasma. The density of the dust particle (nd) in the device is about 1011-1012 m-3. The propagation characteristics of electromagnetic waves are determined by a vector network analyzer with 4-6 GHz antennas. An apparent attenuation by the dust is observed, and the measured attenuation data are approximately in accordance with the theoretical calculations. The effects of gas pressure and input power on the propagation are also investigated. Results show that the transmission attenuation increases with the gas pressure and input power, the charged dust particles play a significant role in the microwave attenuation.

  9. In-situ reactive glow discharge cleaning of NSLS distributed ion pumps

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E.D.; Chou, T.S.

    1988-01-01

    Based on our experience with the in-situ cleaning of optical systems by reactive r.f. glow discharges and the conditioning and preparation of distributed ion pump (DIP) elements, we have sought to develop strategies for recovering from severe vacuum accidents by restoring DIP elements of storage rings such as those at the NSLS in-situ. In this paper we will describe a series of experiments conducted in a test apparatus to condition a so called ''egg-crate'' DIP in-situ, (this older type element being common in older storage rings). A new untreated element which was unable to pump below 5x10 /sup /minus/8/ Torr in its initial condition was treated in oxygen and subsequent argon r.f. discharges utilizing the pump element as the discharge electrode producing a nitrogen pumping speed of 168 l/s at 2x10 /sup /minus/8/ Torr. A light bake at 75/degree/C increased this to nearly 500 l/s at 5x10 /sup /minus/8/ Torr. After exposure to atmosphere the speed was reduced to nil at these pressures but subsequently recovered, without bakeout, by glow discharge cleaning. 22 refs., 6 figs.

  10. Bidimensional characterization of the emission spectra in a direct current atmospheric pressure glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Orejas, Jaime [University of Oviedo, Department of Physics, C/ Gonzazlez Quiros S/N, Mieres (Spain); Pisonero, Jorge, E-mail: pisonerojorge@uniovi.es [University of Oviedo, Department of Physics, C/ Gonzazlez Quiros S/N, Mieres (Spain); Bordel, Nerea [University of Oviedo, Department of Physics, C/ Gonzazlez Quiros S/N, Mieres (Spain); Nelis, Thomas [Bern University of Applied Sciences, Quellgasse 21, 2501 Bienne (Switzerland); Guillot, Philippe [DPHE, CUFR J. F. Champollion, Universite de Toulouse, Place de Verdun, Albi (France); Sanz-Medel, Alfredo, E-mail: asm@uniovi.es [University of Oviedo, Department of Physical and Analytical Chemistry, C/ Julian Claveria 8, Oviedo (Spain)

    2012-10-15

    An in-house atmospheric pressure glow discharge source, designed to be used as ionization/desorption source for ambient mass spectrometry, has been electrically characterized, and its optical emission spectra evaluated in detail. Electrical characterization showed that the plasma regime can vary from glow discharge to arc discharge depending on operating conditions (i.e. He flow rate and inter electrode distance). Furthermore, bidimensional images of the optical emission of some plasma species using filters as wavelength selectors, were registered from inside and outside the discharge chamber (inner region and afterglow region respectively), showing the spatial distribution of excited species (i.e. He*, N{sub 2}{sup +} and O*). These distribution patterns are useful to study the chemistry of the discharge plasma, since different production pathways and different excitation energies affect the presence of these species in the plasma regions. - Highlights: Black-Right-Pointing-Pointer An in-house APGD is characterized through electrical and OES measurements. Black-Right-Pointing-Pointer Interelectrode distance had more effect on electric regime than He flow rate. Black-Right-Pointing-Pointer Internal plume images showed differences on the production pathways for each species. Black-Right-Pointing-Pointer Higher interelectrode distances and He flow rates showed better afterglow conditions.

  11. Carbon dioxide reforming of methane by atmospheric pressure pulsed glow discharge: The effect of pulse compression

    International Nuclear Information System (INIS)

    Ghorbanzadeh, A.; Modarresi, H.

    2006-01-01

    Methane reforming by carbon dioxide in atmospheric pressure pulsed glow discharge was examined. The pulse duration of plasma was compressed to ∼50 ns or lower. This compression allowed working at higher frequencies, more than 3 k Hz, without glow to arc transition. The main outlet gases were synthetic gases (H 2 , CO) and C 2 (ethylene, ethane, and acetylene) products. At equal reactants proportion CO 2 /CH 4 =1, about 42 p ercent o f plasma energy went to chemical dissociation while reactant conversions were relatively high, i.e. near 55 p ercent % (CH 4 ) and 42 p ercent ( CO 2 ). At this point, the energy expenditure was less than 3.8 eV per each converted molecule. The reactor energy performance even gets better at higher CO 2 /CH 4 proportions. At CO 2 /CH 4 =5, The conversions of about 65 p ercent a nd 45 p ercent w ere obtained for methane and carbon dioxide respectively, while energy efficiency reached near 45 p ercent . It is discussed that high nonequilibrium state of vibrational energy at short pulses, especially in carbon dioxide, leads to this improvement.

  12. Comparison of macroscopic properties of electrons in plasmas of beam-plasma and glow discharges

    International Nuclear Information System (INIS)

    Winkler, R.; Wilhelm, J.; Starykh, V.V.

    1979-01-01

    The theoretical basis of the comparison are adequate Boltzmann equations for the electron component of the beam discharge plasma and the glow discharge plasma. We included the turbulent field or the direct electric field in the mentioned plasma types and all important binary collision processes as well as the Coulomb interaction between the charged particles. The comparison was performed in hydrogen under the condition of equal power input per volumen unit of both plasmas in dependence of the turbulence energy per one electron U, for the ionization degree (nsub(e)/N)sub(g) = 10 -6 and the pressure p 0 sup(g) = 1 Torr of the glow discharge plasma and for the ionization degrees (nsub(e)/N)sub(b) = 10 -3 , 10 -2 , 10 -1 and the pressure p 0 sup(b) = 10 -2 Torr of the beam discharge plasma which are typical for the existence of both plasma types. Based upon the numerical solutions of the Boltzmann equations under the mentioned additional conditions we compared the energy distribution functions of the electrons, the mean energy and the power losses of the electrons due to the different collision processes with the molecules and the ions. Especially a law for similarity of the electron kinetics of the two collision dominated plasma types was found and the main channels for the transfer of the field energy in both plasmas were determined. The results obtained were applied for assesing the perspectives of the beam discharged plasma as a plasmachemical reactor. (author)

  13. Determination of trace amounts of impurities in molybdenum by spark source and glow discharge mass spectrometry

    International Nuclear Information System (INIS)

    Saito, Morimasa

    1994-01-01

    For the determination of trace and ultra-trace amounts of impurities in high-purity molybdenum, spark source mass spectrometry and glow discharge mass spectrometry were studied. In spark source mass spectrometry using the metal probe method, the liquid-helium cryogenic pump was used in order to protect the surface of the samples from oxidation. The theoretical relative sensitivity factors (Mo=1) calculated from physical properties were used. The analytical results obtained for molybdenum tablet and high-purity molybdenum were in good agreement with those obtained by other methods (atomic absorption spectrometry and others). In glow discharge mass spectrometry, the relative sensitivity factors were calculated by using the results obtained by spark source mass spectrometry and atomic absorption spectrometry, and this method was applied to the determination of ultra-trace amounts of impurities in ultra high-purity molybdenum and gave the satisfactory results. The detection limits (2σ, n=10) in the integration time of 600 s for U and Th were 0.6 ppb and 0.3 ppb, and the values for Al, Si, Cr, Mn and Cu were in the range of 10 ppb to 0.5 ppb. (author)

  14. Effect of volume and surface charges on discharge structure of glow dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Shao-Wei; He, Feng; Wang, Yu; Li, Lulu; Ouyang, Ji-Ting [School of Physics, Beijing Institute of Technology, Beijing 100081 (China)

    2013-08-15

    The effect of volume and surface charges on the structure of glow dielectric barrier discharge (DBD) has been investigated numerically by using two-dimensional (2D) fluid modeling. The local increase of volume or surface charges induces a kind of activation-inhibition effect, which enhances the local volume discharge and inhibits the discharge in neighborhoods, resulting in non-uniform discharge. The activation-inhibition effect due to the non-uniform volume and/or surface charges depends on the non-uniformity itself and the applied voltage. The activation-inhibition of non-uniform charges has different effects on the volume charges and the accumulated surface charges. The distribution of remaining free charges (seed electrons) in volume at the beginning of voltage pulse plays a key role for the glow DBD structure, resulting in a patterned DBD, when the seed electrons are non-uniform at higher frequency and moderate voltage or uniform DBD, when the seed electrons are uniform at lower frequency or high voltage. The distribution of surface charges is not the determining factor but a result of the formed DBD structure.

  15. Dynamic model based on voltage transfer curve for pattern formation in dielectric barrier glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ben; He, Feng; Ouyang, Jiting, E-mail: jtouyang@bit.edu.cn [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Duan, Xiaoxi [Research Center of Laser Fusion, CAEP, Mianyang 621900 (China)

    2015-12-15

    Simulation work is very important for understanding the formation of self-organized discharge patterns. Previous works have witnessed different models derived from other systems for simulation of discharge pattern, but most of these models are complicated and time-consuming. In this paper, we introduce a convenient phenomenological dynamic model based on the basic dynamic process of glow discharge and the voltage transfer curve (VTC) to study the dielectric barrier glow discharge (DBGD) pattern. VTC is an important characteristic of DBGD, which plots the change of wall voltage after a discharge as a function of the initial total gap voltage. In the modeling, the combined effect of the discharge conditions is included in VTC, and the activation-inhibition effect is expressed by a spatial interaction term. Besides, the model reduces the dimensionality of the system by just considering the integration effect of current flow. All these greatly facilitate the construction of this model. Numerical simulations turn out to be in good accordance with our previous fluid modeling and experimental result.

  16. PRODUCTION OF HIGHER STRENGTH THIN WALLED GLOW DISCHARGE POLYMER SHELLS FOR CRYOGENIC EXPERIMENTS AT OMEGA

    International Nuclear Information System (INIS)

    NIKROO, A; CZECHOWICZ, DG; CASTILLO, ER; PONTELANDOLFO, JM

    2002-01-01

    OAK A271 PRODUCTION OF HIGHER STRENGTH THIN WALLED GLOW DISCHARGE POLYMER SHELLS FOR CRYOGENIC EXPERIMENTS AT OMEGA. Thin walled polymer shells are needed for OMEGA cryogenic laser experiments. These capsules need to be about 900 (micro)m in diameter and as thin as possible (approx 1-2 (micro)m), while having enough strength to be filled with DT as fast as possible to about 1000 atm. The authors have found that by optimizing the coating parameters in the glow discharge polymer (GDP) deposition system, traditionally used for making ICF targets, they can routinely make robust, ∼ 1.5 (micro)m thick, 900 (micro)m diameter GDP shells with buckle strengths of over 0.3 atm. This is twice the strength of shells made prior to the optimization and is comparable to values quoted for polyimide shells. In addition, these shells were found to be approximately three times more permeable and over 20% denser than previously made GDP shells. The combination of higher strength and permeability is ideal for direct drive cryogenic targets at OMEGA. Shells as thin as 0.5 (micro)m have been made. In this paper, the authors discuss the shell fabrication process, effects of modifying various GDP deposition parameters on shell properties and chemical composition

  17. High-Energy Radiation from Thunderstorms with ADELE: TGFs, Steps, and Glows

    Science.gov (United States)

    Smith, David M.; Kelley, Nicole; Martinez-McKinney, Forest; Zhang, Zi Yan; Hazelton, Bryna; Grefenstette, Brian; Splitt, Michael; Lazarus, Steven; Ulrich, William; Levine, Steven; hide

    2011-01-01

    The biggest challenge in the study of high-energy processes in thunderstorms is getting a detector to the vicinity of the electrically active regions of a storm. The Airborne Detector for Energetic Lightning Emissions (ADELE) has been used to detect gamma rays from aircraft above storms and from a storm-chasing van on the ground. In August 2009, ADELE flew above Florida storms in a Gulfstream V jet, detecting the first terrestrial gamma-ray flash (TGF) seen from a plane and continuous glows of high-energy emission above thunderclouds. The presence of these glows suggests that a gradual process of relativistic runaway and feedback may help limit the total amount of charging in thunderstorms, in contrast to the traditional view that only lightning discharges compete with the charging process. The upper limits on TGF emission from intracloud and cloud-to-ground lightning from the ADELE flights demonstrated conclusively that a TGF of the sort seen from space is not associated with most lightning and not necessary to trigger it. In August 2010, observations from a van detected stepped-leader x-ray emission from at least four lightning strikes in ten days of operations. This mode of operation is therefore promising for future observations of the stepping process, although a more varied suite of instrumentation, in particular a flash-distance detector, would be useful. We will report on these results and on future possibilities for ADELE campaigns.

  18. In-situ reactive glow discharge cleaning of NSLS distributed ion pumps

    International Nuclear Information System (INIS)

    Johnson, E.D.; Chou, T.S.

    1988-01-01

    Based on our experience with the in-situ cleaning of optical systems by reactive r.f. glow discharges and the conditioning and preparation of distributed ion pump (DIP) elements, we have sought to develop strategies for recovering from severe vacuum accidents by restoring DIP elements of storage rings such as those at the NSLS in-situ. In this paper we will describe a series of experiments conducted in a test apparatus to condition a so called ''egg-crate'' DIP in-situ, (this older type element being common in older storage rings). A new untreated element which was unable to pump below 5x10 /sup /minus/8/ Torr in its initial condition was treated in oxygen and subsequent argon r.f. discharges utilizing the pump element as the discharge electrode producing a nitrogen pumping speed of 168 l/s at 2x10 /sup /minus/8/ Torr. A light bake at 75/degree/C increased this to nearly 500 l/s at 5x10 /sup /minus/8/ Torr. After exposure to atmosphere the speed was reduced to nil at these pressures but subsequently recovered, without bakeout, by glow discharge cleaning. 22 refs., 6 figs

  19. Borax as flux on sintering of iron Ancor Steel 1000® under glow discharge

    Science.gov (United States)

    Ariza Suarez, H. G.; Sarmiento Santos, A.; Ortiz Otálora, C. A.

    2016-02-01

    This work studies the flux effect of borax (di sodium tetraborate decahydrate) on sintering of iron Ancor Steel 1000® in abnormal glow discharge. The incidence of the percentage by weight of borax and the sintering temperature in the process were observed. Samples of powder metallurgical iron were prepared with proportions of 0.50%, 2.0%, 4.0% and 6.0% by weight of borax using the procedures of powder metallurgy. The samples were sintered at 800 and 1100°C for 30min, by glow discharge at low pressure in a reducing atmosphere composed of 20% H2+80% Ar. The samples in compact green-state were analyzed by TGA-DSC to determine the fusion process and mass loss during sintering. The analysis of microhardness and density, shows that at a sintering temperature of 800°C the sample density decreases and the sample microhardness increases with respect to sintered samples without borax. Sintered samples were analysed by DRX showing the absence of precipitates.

  20. Thermoluminescence response and glow curve structure of Sc2TiO5 ß-irradiated

    International Nuclear Information System (INIS)

    Muñoz, I.C.; Brown, F.; Durán-Muñoz, H.; Cruz-Zaragoza, E.; Durán-Torres, B.; Alvarez-Montaño, V.E.

    2014-01-01

    Discandium titanate (Sc 2 TiO 5 ) powder was synthesized in order to analyze its thermoluminescence (TL) response. The TL glow curve structure shows two peaks: at 453–433 K and at 590–553 K. The TL beta dose–response has a linear behavior over the dose range 50–500 Gy. The T stop preheat method shows five glow peaks that were taken into account to calculate the kinetic parameters using the CGCD procedure. TL results support the possible use of Sc 2 TiO 5 as a new phosphor in high ß-dose dosimetry. - Highlights: • Discandium titanate was synthesized, and its TL properties were analyzed. • The beta dose–response has a linear behavior on the dose range 50–500 Gy. • The kinetic parameters were obtained by the CGCD procedure. • Results support the possible use of Sc 2 TiO 5 as a new phosphor for ß-dose dosimetry

  1. Decomposition of toluene in a steady-state atmospheric-pressure glow discharge

    International Nuclear Information System (INIS)

    Trushkin, A. N.; Grushin, M. E.; Kochetov, I. V.; Trushkin, N. I.; Akishev, Yu. S.

    2013-01-01

    Results are presented from experimental studies of decomposition of toluene (C 6 H 5 CH 3 ) in a polluted air flow by means of a steady-state atmospheric pressure glow discharge at different water vapor contents in the working gas. The experimental results on the degree of C 6 H 5 CH 3 removal are compared with the results of computer simulations conducted in the framework of the developed kinetic model of plasma chemical decomposition of toluene in the N 2 : O 2 : H 2 O gas mixture. A substantial influence of the gas flow humidity on toluene decomposition in the atmospheric pressure glow discharge is demonstrated. The main mechanisms of the influence of humidity on C 6 H 5 CH 3 decomposition are determined. The existence of two stages in the process of toluene removal, which differ in their duration and the intensity of plasma chemical decomposition of C 6 H 5 CH 3 is established. Based on the results of computer simulations, the composition of the products of plasma chemical reactions at the output of the reactor is analyzed as a function of the specific energy deposition and gas flow humidity. The existence of a catalytic cycle in which hydroxyl radical OH acts a catalyst and which substantially accelerates the recombination of oxygen atoms and suppression of ozone generation when the plasma-forming gas contains water vapor is established.

  2. Decomposition of toluene in a steady-state atmospheric-pressure glow discharge

    Science.gov (United States)

    Trushkin, A. N.; Grushin, M. E.; Kochetov, I. V.; Trushkin, N. I.; Akishev, Yu. S.

    2013-02-01

    Results are presented from experimental studies of decomposition of toluene (C6H5CH3) in a polluted air flow by means of a steady-state atmospheric pressure glow discharge at different water vapor contents in the working gas. The experimental results on the degree of C6H5CH3 removal are compared with the results of computer simulations conducted in the framework of the developed kinetic model of plasma chemical decomposition of toluene in the N2: O2: H2O gas mixture. A substantial influence of the gas flow humidity on toluene decomposition in the atmospheric pressure glow discharge is demonstrated. The main mechanisms of the influence of humidity on C6H5CH3 decomposition are determined. The existence of two stages in the process of toluene removal, which differ in their duration and the intensity of plasma chemical decomposition of C6H5CH3 is established. Based on the results of computer simulations, the composition of the products of plasma chemical reactions at the output of the reactor is analyzed as a function of the specific energy deposition and gas flow humidity. The existence of a catalytic cycle in which hydroxyl radical OH acts a catalyst and which substantially accelerates the recombination of oxygen atoms and suppression of ozone generation when the plasma-forming gas contains water vapor is established.

  3. Corona Glow Discharge Plasma Treatment for Hidrophylicity Improvement of Polyester and Cotton Fabrics

    Science.gov (United States)

    Susan, A. I.; Widodo, M.; Nur, M.

    2017-07-01

    The effects of irradiation by a corona glow discharge plasma on hidrophylicity properties of polyester and cotton fabrics were investigated. We used a corona glow discharge plasma reactor with multiple points to plane electrodes, which was generated by a high voltage DC. Factors that affect the hidrophylicity properties were identified and evaluated as functions of irradiation parameters, which include duration of treatment, distance between electrodes, and bias voltage. It was readily observed from SEM examinations that plasma changed the surface morphology of both polyester and cotton fibers, giving result to an increased roughness to both of them. Results also showed that the hidrophylicityof polyester and cotton fabrics improved by the treatment, which is proportional to the time of treatment and voltage, but inversely proportional to the distance between electrodes. Time of treatment that provided the optimum enhancement of hidrophylicity for cotton is 15 minutes which improved the wetting time from 8.16 seconds to 1.26 seconds. For polyester, it took 15 minutes of irradiation time to improve the wetting time from 7340 seconds to 2905 seconds. The optimum distance between electrodes for both fabrics in this study was found to be 2 cm. Further analysis showed that the improved hidrophylicity properties is due to the creation of surface radicals by free radicals in the plasma leading to the formation of new water-attracting functional groups on the fiber surface.

  4. Quantum machine learning with glow for episodic tasks and decision games

    Science.gov (United States)

    Clausen, Jens; Briegel, Hans J.

    2018-02-01

    We consider a general class of models, where a reinforcement learning (RL) agent learns from cyclic interactions with an external environment via classical signals. Perceptual inputs are encoded as quantum states, which are subsequently transformed by a quantum channel representing the agent's memory, while the outcomes of measurements performed at the channel's output determine the agent's actions. The learning takes place via stepwise modifications of the channel properties. They are described by an update rule that is inspired by the projective simulation (PS) model and equipped with a glow mechanism that allows for a backpropagation of policy changes, analogous to the eligibility traces in RL and edge glow in PS. In this way, the model combines features of PS with the ability for generalization, offered by its physical embodiment as a quantum system. We apply the agent to various setups of an invasion game and a grid world, which serve as elementary model tasks allowing a direct comparison with a basic classical PS agent.

  5. The nonlocal electron kinetics for a low-pressure glow discharge dusty plasma

    Science.gov (United States)

    Liang, Yonggan; Wang, Ying; Li, Hui; Tian, Ruihuan; Yuan, Chengxun; Kudryavtsev, A. A.; Rabadanov, K. M.; Wu, Jian; Zhou, Zhongxiang; Tian, Hao

    2018-05-01

    The nonlocal electron kinetic model based on the Boltzmann equation is developed in low-pressure argon glow discharge dusty plasmas. The additional electron-dust elastic and inelastic collision processes are considered when solving the kinetic equation numerically. The orbital motion limited theory and collision enhanced collection approximation are employed to calculate the dust surface potential. The electron energy distribution function (EEDF), effective electron temperature Teff, and dust surface potential are investigated under different plasma and dust conditions by solving the Boltzmann and the dust charging current balance equations self-consistently. A comparison of the calculation results obtained from nonlocal and local kinetic models is made. It is shown that the appearance of dust particles leads to a deviation of the EEDF from its original profile for both nonlocal and local kinetic models. With the increase in dust density and size, the effective electron temperature and dust surface potential decrease due to the high-energy electron loss on the dust surface. Meanwhile, the nonlocal and local results differ much from each other under the same calculation condition. It is concluded that, for low-pressure (PR ≤ 1 cm*Torr) glow discharge dusty plasmas, the existence of dust particles will amplify the difference of local and nonlocal EEDFs, which makes the local kinetic model more improper to determine the main parameters of the positive column. The nonlocal kinetic model should be used for the calculation of the EEDFs and dusty plasma parameters.

  6. APIO-EE-9 is a novel Aurora A and B antagonist that suppresses esophageal cancer growth in a PDX mouse model.

    Science.gov (United States)

    Jin, Guoguo; Yao, Ke; Guo, Zhiping; Zhao, Zhenjiang; Liu, Kangdong; Liu, Fangfang; Chen, Hanyong; Gorja, Dhilli Rao; Reddy, Kanamata; Bode, Ann M; Dong, Ziming; Dong, Zigang

    2017-08-08

    Esophageal cancer (EC) is one of the most aggressive malignancies of the upper aerodigestive tract. Over the past three decades, with advances in surgical techniques and treatment, the prognosis of esophageal cancer has only slowly improved. Thus identifying novel molecular targets and developing therapeutic agents are critical. Aurora kinases play a crucial role in mitosis and selective inhibitors might provide an effective therapeutic treatment for cancer. However, the role of Aurora kinases in EC is still inadequately studied. Here, we identified a novel compound, referred to as APIO-EE-9, which inhibits growth and colony formation and induces apoptosis of esophageal cancer cells. Using computer modeling, we found that APIO-EE-9 interacted with both Aurora A and B in the ATP-binding pocket. APIO-EE-9 inhibited both Aurora A and B kinase activities in a dose-dependent manner. Treatment with APIO-EE-9 substantially reduced the downstream Aurora kinase phosphorylation of histone H3 (Ser10), resulting in formation of multiple nuclei and centrosomes. Additionally, esophageal cancer cells expressing shAurora A or shAurora B kinase exhibited a dramatic reduction in proliferation and colony formation. Injection of these cells as xenografts in mice reduced tumor formation compared to wildtype cells. Importantly, APIO-EE-9 significantly decreased the size of esophageal patient-derived xenograft (PDX) tumors implanted in SCID mice. These results demonstrated that APIO-EE-9 is a specific Aurora kinase inhibitor that could be developed as a therapeutic agent against esophageal cancer.

  7. Rosmarinic acid plays a protective role in the embryogenesis of zebrafish exposed to food colours through its influence on aurora kinase A level.

    Science.gov (United States)

    Swarnalatha, Y; Jerrine Joseph, I S; Jayakrishna, Tippabathani

    2017-05-01

    To evaluate the protective nature of the rosmarinic acid from Sphaeranthus amaranthoides during zebra fish embryogenesis. Rosmarinic acid was isolated from the S. amaranthoides. An accurate, sensitive and simple LC-MS analysis was performed to determine the rosmarinic acid from S. amaranthoides. In the present study, zebrafish embryos were exposed to crimson red and sunset yellow at a concentration of 0.1 and 0.5mg/l and the effect of these food colours on the levels of aurora kinase A was studied individually. Aurora kinase A levels are crucial for embryogenesis in zebrafish which is used as model in this study. The decrease of aurora kinase A levels in food colour treated embryos influences the embryogenesis, resulting in short and bent trunk leading to cell death and growth retardation. Elevated levels of aurora kinase A in rosmarinic acid treated groups can be attributed to the restoration of normal growth in zebra fish embryos with well developed brain and eyes. Further insilico docking studies were carried out and target was identified as rosmarinic acid. From the docking studies the docking poses and binding energy confirms that aurora kinase A is the target for rosmarinic acid. Rosmarinic acid was found to play a protective role in the embryogenesis of zebra fish exposed to food colours (crimson red and sunset yellow) through its influence on aurora kinase A levels. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  8. CyclinG1 Amplification Enhances Aurora Kinase Inhibitor-Induced Polyploid Resistance and Inhibition of Bcl-2 Pathway Reverses the Resistance

    Directory of Open Access Journals (Sweden)

    Wenfeng Zhang

    2017-08-01

    Full Text Available Background/Aims: CyclinG1 (CycG1 is frequently overexpressed in solid tumors and overexpression of CycG1 promotes cell survival upon paclitaxel exposure by inducing polyploidy. Whether and how CycG1 regulates polyploidization caused by small molecular targeted inhibitors remains unclear. Methods: Immunohistochemistry and immunoblotting were utilized to examine protein expression. Cell proliferation was measured by ATPlite assay, and cell cycle distribution and apoptosis were measured by flow cytometry and/or DNA fragmentation assays. Results: Overexpression of CycG1 in breast cancer cells caused apoptosis-resistant polyploidy upon treatment with Aurora kinase inhibitor, ZM447439 (ZM. Addition of ABT-263, a small-molecule BH3 mimetic, to ZM, produced a synergistic loss of cell viability with greater sustained tumor growth inhibition in breast cancer cell lines. Decrease of Mcl-1 and increase of NOXA caused by ZM treatment, were responsible for the synergy. Furthermore, CycG1 was highly expressed in Triple-Negative-Breast-Cancer patients treated with paclitaxel and was paralleled by decreased cell survival. Conclusion: CycG1 is a crucial factor in ZM-induced polyploidy resistance, and ABT-263/ZM combination hold therapeutic utility in the CycG1-amplified subset of breast cancer and CycG1, thus, is a promising target in breast cancer.

  9. Analysis of the glow curve of SrB 4O 7:Dy compounds employing the GOT model

    Science.gov (United States)

    Ortega, F.; Molina, P.; Santiago, M.; Spano, F.; Lester, M.; Caselli, E.

    2006-02-01

    The glow curve of SrB 4O 7:Dy phosphors has been analysed with the general one trap model (GOT). To solve the differential equation describing the GOT model a novel algorithm has been employed, which reduces significantly the deconvolution time with respect to the time required by usual integration algorithms, such as the Runge-Kutta method.

  10. Analysis of the glow curve of SrB4O7:Dy compounds employing the GOT model

    International Nuclear Information System (INIS)

    Ortega, F.; Molina, P.; Santiago, M.; Spano, F.; Lester, M.; Caselli, E.

    2006-01-01

    The glow curve of SrB 4 O 7 :Dy phosphors has been analysed with the general one trap model (GOT). To solve the differential equation describing the GOT model a novel algorithm has been employed, which reduces significantly the deconvolution time with respect to the time required by usual integration algorithms, such as the Runge-Kutta method

  11. Relation between fine structure of energy spectra for pulsating aurora electrons and frequency spectra of whistler mode chorus waves

    Czech Academy of Sciences Publication Activity Database

    Miyoshi, Y.; Saito, S.; Seki, K.; Nishiyama, T.; Kataoka, R.; Asamura, K.; Katoh, Y.; Ebihara, Y.; Sakanoi, T.; Hirahara, M.; Oyama, S.; Kurita, S.; Santolík, Ondřej

    2015-01-01

    Roč. 120, č. 9 (2015), s. 7728-7736 ISSN 2169-9380 R&D Projects: GA MŠk LH12231 Institutional support: RVO:68378289 Keywords : pulsating aurora * chorus waves * wave-particle interactions * computer simulation * Reimei satellite Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.318, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/2015JA021562/full

  12. Resonant dissociation in N2 by electron impact: a source of heating in the thermosphere and auroras

    International Nuclear Information System (INIS)

    Spence, D.; Burrow, P.D.

    1979-01-01

    An electron impact resonant dissociation process, leading to superthermal atom production in molecular nitrogen is described. The maximum cross section for this process is found to be 2.5 x 10 -18 cm 2 at 10 eV. Measurements of scattered electrons indicate a value of -65 to -90 MeV for the electron affinity of N. The possible role of resonant dissociation as a source of heating in the thermosphere and in auroras is discussed

  13. Retratos de Aurora: Deconstrucción de una memoria derrumbada

    Directory of Open Access Journals (Sweden)

    Nicolás Sáez Gutiérrez

    2017-12-01

    Full Text Available Hemos decido publicar en este número el proyecto Retratos de Aurora coordinado por Walter Blas1 , como una manera de visibilizar acciones que desde el arte y su enseñanza logran transcender al entorno donde se ha efectuado dicha acción. Aquí la fotografía y el propio aparato fotográfico son el medio instrumental propuesto para construir la historia viva de la emblemática población “Aurora de Chile”.2 Las vecinas y vecinos fueron invitados por Walter a construir artesanalmente cámaras estenopeicas (sin lente adaptando objetos de su cotidiano y su memoria. Una antigua caja de madera, un lechero de aluminio, un madero de la antigua fábrica, un motor de arranque y hasta el estuche de un acordeón reliquia familiar son las formas cotidianas que se transformaron en mecanismos de captura fotográfica del propio territorio. Estos inventos caseros permitieron no solo comprender didácticamente el procedimiento técnico de la fijación química de la imagen producida por el fenómeno físico lumínico conocido como “cámara obscura”, si no que a dar un nuevo y mágico destino a estas “cámaras latentes”. Objetos que cargan con sus respectivos "relatos de existencia”, se transforman y vuelven a tener una utilidad impensada que las conecta con la intimidad familiar y la memoria colectiva. Desde ahí son operadas para construir un imaginario actualizado de lo que ha sido la población hasta hoy y para ser parte de una especie de inventario visual que prevalezca en el tiempo, como bien lo dijo Sontag “la fotografía es un inventario de la inmortalidad”.3 Las fotografías estenopeicas resultantes construyen un nuevo paisaje de la población “Aurora de Chile”. Un paisaje de resistencia, que enaltece su patrimonio humano y cultural, que activa a la memoria pasada pero que sabe construirá la futura... que desea ser un paisaje discursivo que denuncia su empoderada existencia. En nuestra actual era de la

  14. Response of Jupiter's Aurora to Plasma Mass Loading Rate Monitored by the Hisaki Satellite During Volcanic Eruptions at Io

    Science.gov (United States)

    Kimura, T.; Hiraki, Y.; Tao, C.; Tsuchiya, F.; Delamere, P. A.; Yoshioka, K.; Murakami, G.; Yamazaki, A.; Kita, H.; Badman, S. V.; Fukazawa, K.; Yoshikawa, I.; Fujimoto, M.

    2018-03-01

    The production and transport of plasma mass are essential processes in the dynamics of planetary magnetospheres. At Jupiter, it is hypothesized that Io's volcanic plasma carried out of the plasma torus is transported radially outward in the rotating magnetosphere and is recurrently ejected as plasmoid via tail reconnection. The plasmoid ejection is likely associated with particle energization, radial plasma flow, and transient auroral emissions. However, it has not been demonstrated that plasmoid ejection is sensitive to mass loading because of the lack of simultaneous observations of both processes. We report the response of plasmoid ejection to mass loading during large volcanic eruptions at Io in 2015. Response of the transient aurora to the mass loading rate was investigated based on a combination of Hisaki satellite monitoring and a newly developed analytic model. We found that the transient aurora frequently recurred at a 2-6 day period in response to a mass loading increase from 0.3 to 0.5 t/s. In general, the recurrence of the transient aurora was not significantly correlated with the solar wind, although there was an exceptional event with a maximum emission power of 10 TW after the solar wind shock arrival. The recurrence of plasmoid ejection requires the precondition that an amount comparable to the total mass of magnetosphere, 1.5 Mt, is accumulated in the magnetosphere. A plasmoid mass of more than 0.1 Mt is necessary in case that the plasmoid ejection is the only process for mass release.

  15. Combining the pan-aurora kinase inhibitor AMG 900 with histone deacetylase inhibitors enhances antitumor activity in prostate cancer

    International Nuclear Information System (INIS)

    Paller, Channing J; Wissing, Michel D; Mendonca, Janet; Sharma, Anup; Kim, Eugene; Kim, Hea-Soo; Kortenhorst, Madeleine S Q; Gerber, Stephanie; Rosen, Marc; Shaikh, Faraz; Zahurak, Marianna L; Rudek, Michelle A; Hammers, Hans; Rudin, Charles M; Carducci, Michael A; Kachhap, Sushant K

    2014-01-01

    Histone deacetylase inhibitors (HDACIs) are being tested in clinical trials for the treatment of solid tumors. While most studies have focused on the reexpression of silenced tumor suppressor genes, a number of genes/pathways are downregulated by HDACIs. This provides opportunities for combination therapy: agents that further disable these pathways through inhibition of residual gene function are speculated to enhance cell death in combination with HDACIs. A previous study from our group indicated that mitotic checkpoint kinases such as PLK1 and Aurora A are downregulated by HDACIs. We used in vitro and in vivo xenograft models of prostate cancer (PCA) to test whether combination of HDACIs with the pan-aurora kinase inhibitor AMG 900 can synergistically or additively kill PCA cells. AMG 900 and HDACIs synergistically decreased cell proliferation activity and clonogenic survival in DU-145, LNCaP, and PC3 PCA cell lines compared to single-agent treatment. Cellular senescence, polyploidy, and apoptosis was significantly increased in all cell lines after combination treatment. In vivo xenograft studies indicated decreased tumor growth and decreased aurora B kinase activity in mice treated with low-dose AMG 900 and vorinostat compared to either agent alone. Pharmacodynamics was assessed by scoring for phosphorylated histone H3 through immunofluorescence. Our results indicate that combination treatment with low doses of AMG 900 and HDACIs could be a promising therapy for future clinical trials against PCA

  16. Antifouling activity by sea anemone (Heteractis magnifica and H. aurora extracts against marine biofilm bacteria Actividades antiincrustantes de las extractos de las anémonas marinas Heteractis magnifica y H. aurora frente a biofilm de bacterias marinas

    Directory of Open Access Journals (Sweden)

    Subramanian Bragadeeswaran

    2011-07-01

    Full Text Available Sea anemones (Actiniaria are solitary, ocean-dwelling members of the phylum Cnidaria and the class Anthozoa. In this study, we screened antibacterial activity of two benthic sea anemones (Heteractis magnifica and H. aurora collected from the Mandapam coast of southeast India. Crude extracts of the sea anemone were assayed against seven bacterial biofilms isolated from three different test panels. The crude extract of H. magnifica showed a maximum inhibition zone of 18 mm against Pseudomonas sp. and Escherichia coli and a minimum inhibition zone of 3 mm against Pseudomonas aeruginosa, Micrococcus sp., and Bacillus cerens for methanol, acetone, and DCM extracts, respectively. The butanol extract of H. aurora showed a maximum inhibition zone of 23 mm against Vibrio parahaemolyticus, whereas the methanol extract revealed a minimum inhibition zone of 1 mm against V. parahaemolyticus. The present study revealed that the H. aurora extracts were more effective than those of H. magnifica and that the active compounds from the sea anemone can be used as antifouling compounds.Las anémonas de mar (Actiniaria son solitarias, habitantes oceánicos del phylum Cnidaria y de la clase Anthozoa. En este estudio se determina la actividad antibacteriana de dos anémonas bentónicas Heteractis magnifica y H. aurora recolectadas en la costa de Mandapam, sudeste de India. Los extractos crudos de estas anémonas fueron ensayados frente a siete biofilms bacterianos aislados de tres paneles de control distintos. El extracto crudo de la anémona H. magnifica mostró una zona inhibición máxima de 18 mm contra Psudomonas sp. y Escherichia coli y la zona de inhibición mínima de 3 mm fue encontrada frente a Pseudomonas aeruginosa, Micrococus sp. y Bacillus cerens de extractos de metanol, acetona y DCM respectivamente. El extracto de butanol de la anémona H. magnifica mostró una zona de inhibición máxima de 23 mm frente a Vibrio parahemolyticus, mientras que con el

  17. Emission characteristics of 6.78-MHz radio-frequency glow discharge plasma in a pulsed mode

    Science.gov (United States)

    Zhang, Xinyue; Wagatsuma, Kazuaki

    2017-07-01

    This paper investigated Boltzmann plots for both atomic and ionic emission lines of iron in an argon glow discharge plasma driven by 6.78-MHz radio-frequency (RF) voltage in a pulsed operation, in order to discuss how the excitation/ionization process was affected by the pulsation. For this purpose, a pulse frequency as well as a duty ratio of the pulsed RF voltage was selected as the experimenter parameters. A Grimm-style radiation source was employed at a forward RF power of 70 W and at an argon pressures of 670 Pa. The Boltzmann plot for low-lying excited levels of iron atom was on a linear relationship, which was probably attributed to thermal collisions with ultimate electrons in the negative glow region; in this case, the excitation temperature was obtained in a narrow range of 3300-3400 K, which was hardly affected by the duty ratio as well as the pulse frequency of the pulsed RF glow discharge plasma. This observation suggested that the RF plasma could be supported by a self-stabilized negative glow region, where the kinetic energy distribution of the electrons would be changed to a lesser extent. Additional non-thermal excitation processes, such as a Penning-type collision and a charge-transfer collision, led to deviations (overpopulation) of particular energy levels of iron atom or iron ion from the normal Boltzmann distribution. However, their contributions to the overall excitation/ionization were not altered so greatly, when the pulse frequency or the duty ratio was varied in the pulsed RF glow discharge plasma.

  18. Alfvén Waves and the Aurora (Hannes Alfvén Medal Lecture)

    Science.gov (United States)

    Lysak, Robert

    2015-04-01

    The most compelling visual evidence of plasma processes in the magnetosphere of Earth as well as the other magnetized planets is the aurora. Over 40 years of research have indicated that the aurora is a consequence of the acceleration of charged particles toward the neutral atmosphere, where the excitation of neutral atoms and their subsequent relaxation to the ground state produces the auroral light. Much of this acceleration can be described by acceleration in a quasi-static electric field parallel to the geomagnetic field, producing nearly monoenergetic beams of electrons. While a variety of quasi-static models to describe such parallel electric fields have been developed, the dynamics of how these fields evolve is still an open question. Satellite measurements have indicated that a primary source of energy to support these fields is the Poynting flux associated with shear Alfvén waves propagating along auroral field lines. These Alfvén waves are generated in the magnetosphere and reflect from the ionosphere. On closed field lines, Alfvén waves bouncing between conjugate ionospheres produce field line resonances that have be observed both in space and by ground magnetometers. However, some auroral emissions do not follow this scenario. In these cases, the accelerated electrons are observed to have a broad energy spectrum, rather than a monoenergetic peak. Such a spectrum is suggestive of a time-dependent acceleration process that operates on a time scale of a few seconds, comparable to the electron transit time across the acceleration region. While field line resonances have a time scale on the order of minutes, waves with periods of a few seconds can be produced by partial reflections in the Ionospheric Alfvén Resonator, a resonant cavity formed by the rapid decrease of the plasma density and increase of the Alfvén speed above the ionosphere. In order to develop a parallel electric field that can accelerate auroral particles, these Alfvén waves must

  19. Pliocene to late Pleistocene magmatism in the Aurora Volcanic Field, Nevada and California, USA

    Science.gov (United States)

    Kingdon, S.; Cousens, B.; John, D. A.; du Bray, E. A.

    2013-12-01

    The 3.9- 0.1 Ma Aurora Volcanic Field (AVF) covers 325 km2 east and southeast of the Bodie Hills, north of Mono Lake, California, USA. The AVF is located immediately northwest of the Long Valley magmatic system and adjacent and overlapping the Miocene Bodie Hills Volcanic Field (BHVF). Rock types range from trachybasalt to trachydacite, and high-silica rhyolite. The trachybasalts to trachydacites are weakly to moderately porphyritic (1-30%) with variable phenocryst assemblages that are some combination of plagioclase, hornblende, clinopyroxene, and lesser orthopyroxene, olivine, and/or biotite. Microphenocrysts are dominated by plagioclase, and include opaque oxides, clinopyroxene, and apatite. These rocks are weakly to strongly devitrified. The high-silica rhyolites are sparsely porphyritic with trace to 10% phenocrysts of quartz, sanidine, plagioclase, biotite, (+/- hornblende), accessory opaque oxide minerals, titanite, allanite, (+/-apatite, zircon), and have glassy groundmasses. Rocks in the AVF are less strongly porphyritic than those of BHVF. Plagioclase phenocrysts are often oscillatory zoned and many have sieve texture. Amphiboles have distinct black opaque rims. Xenocrystic quartz and plagioclase are rare. AVF lavas have bimodal SiO2 compositions, ranging from 49 to 78 wt%, with a gap between 65 and 75 wt%. They are high-K calc-alkaline to shoshonitic in composition, and are metaluminous to weakly peraluminous. They are enriched in rare earth elements (REE), especially light REEs, compared to the Miocene BHVF rocks. Primordial mantle-normalized incompatible element patterns show arc- or subduction-related signatures, with enrichment in Ba and Pb, and depletion in Nb and Ta. Enrichment in K and Sr and depletion in Ti are less pronounced than in the BHVF rocks. There is no correlation between lead isotope ratios and silica (initial 206Pb/204Pb ratios range from 18.974 to 19.151). Neodymium isotope ratios show a moderate negative correlation with silica

  20. A statistical analysis of the location and width of Saturn's southern auroras

    Directory of Open Access Journals (Sweden)

    S. V. Badman

    2006-12-01

    Full Text Available A selection of twenty-two Hubble Space Telescope images of Saturn's ultraviolet auroras obtained during 1997–2004 has been analysed to determine the median location and width of the auroral oval, and their variability. Limitations of coverage restrict the analysis to the southern hemisphere, and to local times from the post-midnight sector to just past dusk, via dawn and noon. It is found that the overall median location of the poleward and equatorward boundaries of the oval with respect to the southern pole are at ~14° and ~16° co-latitude, respectively, with a median latitudinal width of ~2°. These median values vary only modestly with local time around the oval, though the poleward boundary moves closer to the pole near noon (~12.5° such that the oval is wider in that sector (median width ~3.5° than it is at both dawn and dusk (~1.5°. It is also shown that the position of the auroral boundaries at Saturn are extremely variable, the poleward boundary being located between 2° and 20° co-latitude, and the equatorward boundary between 6° and 23°, this variability contrasting sharply with the essentially fixed location of the main oval at Jupiter. Comparison with Voyager plasma angular velocity data mapped magnetically from the equatorial magnetosphere into the southern ionosphere indicates that the dayside aurora lie poleward of the main upward-directed field-aligned current region associated with corotation enforcement, which maps to ~20°–24° co-latitude, while agreeing reasonably with the position of the open-closed field line boundary based on estimates of the open flux in Saturn's tail, located between ~11° and ~15°. In this case, the variability in location can be understood in terms of changes in the open flux present in the system, the changes implied by the Saturn data then matching those observed at Earth as fractions of the total planetary flux. We infer that the broad (few degrees diffuse auroral emissions

  1. DC Glow Discharge Plasma, Containing Dust Particles: Self Organization and Peculiarities of Behavior

    International Nuclear Information System (INIS)

    Molotkov, V.I.; Pustyl'nik, M.Y.; Torchinskij, V.M.; Fortov, V.E.

    2003-01-01

    Dust particles, immersed in a plasma, acquire charge due to which they may be electrostatically trapped in a plasma. The energy of the interaction of the dust particles may be enough to transfer the dust component to nonideal and even crystalline state. This phenomenon is observed in various plasmas. In the present work a review of the investigations of strongly nonideal dusty plasma of the dc glow discharge striations is given. The formation of plasma crystals, liquids and plasma liquid crystals is considered. Typical phenomenon a for the dc discharge dusty plasma, such as coexistence of different phases in a single structure, convective motions, dust acoustic instability, are underlined. Results of the experiments on different external influences on dusty plasma structures are stated. It is shown that external influences may be used for measuring of the particle charge and field of forces acting on a dust grain levitating in a plasma. (author)

  2. Effects of the ion-solid interaction in glow discharge vapour deposition polymerization of pyromellitic dianhydride

    International Nuclear Information System (INIS)

    Maggioni, G.; Carturan, S.; Rigato, V.; Pieri, U.

    2000-01-01

    Low energy He ion bombardment of pyromellitic dianhydride monomer used in glow discharge vapour deposition polymerization (GDVDP) of polyimide coatings and its effects on the film deposition process have been studied. The sublimation of the monomer molecules and the simultaneous formation of a damaged, carbon-rich surface layer on the target are discussed from a theoretical point of view based on simulations of the ion-solid interaction. Optical emission and mass spectrometry have been used to analyse the species emitted from the target. In order to study the time evolution of the PMDA target damage, the deposition rate of monomer molecules has been monitored. FT-IR spectroscopy has been used to determine the molecular damaging of the target monomer and deposited films

  3. Study of surface atmospheric pressure glow discharge plasma based on ultrathin laminated electrodes in air

    Science.gov (United States)

    Zhao, Luxiang; Liu, Wenzheng; Li, Zhiyi; Ma, Chuanlong

    2018-05-01

    A method to generate large-area surface plasma in air by micro-discharge is proposed. Two ultrathin laminated electrode structures of non-insulating and insulating types were formed by using the nanoscale ITO conductive layer. The surface glow discharge in atmospheric air is realized in low discharge voltage by constructing the special electric field of two-dimensional unidirectional attenuation. In particular, the insulating electrode structure can avoid the loss of ITO electrodes so that the discharge stability can be increased, and the treated objects can be prevented from metal ion pollution caused by the electrode in the discharge. It has broad application prospects in the fields of aerodynamics and material surface treatment.

  4. Surface enrichment with chrome and nitriding of IF steel under an abnormal glow discharge

    International Nuclear Information System (INIS)

    Meira, S.R.; Borges, P.C.; Bernardelli, E.A.

    2014-01-01

    The objective of this work is to evaluate the influence of surface enrichment of IF steel with chrome, and nitriding, the formation of the nitrided layer. Thus, IF steel samples were subjected to surface enrichment process, using 409 stainless steel as a target for sputtering, followed by plasma nitriding, both under a dc abnormal glow discharge. The enrichment treatment was operated at 1200 ° C for 3h. The nitriding treatment was operated at 510 ° C for 2 h. The influence of the treatments on the layers formed was studied through optical microscopy (OM), scan electron microscopy (SEM), X-ray diffraction (XRD) and Vickers microindentation. The results show that the enrichment is effective to enrich the IF surface, furthermore, improves the characteristics of nitriding, comparing nitriding samples to nitriding and enriched, was observed needles of nitrides, as well as a higher hardness, which is associated with the nitrides of chrome, on the nitriding and enriched samples. (author)

  5. Sputtering and emission intensity of copper alloys in a Grimm glow lamp

    International Nuclear Information System (INIS)

    Yamada, T.; Kashima, J.; Naganuma, K.

    1981-01-01

    The effects of the metallurgical structure and the aluminium content of copper-aluminium alloy (1-12% Al) on the sputtering and intensities of spectral lines in the Grimm glow lamp are reported. The electrical current and sputtering yield decreased linearly with increasing aluminium content; the intensities of the Al I lines depended linearly on the amount of aluminium in the sputtering yield at a fixed voltage and argon pressure. The structure affected the intensities of the Al I and Cu I lines but not the intensity ratio (Al I/Cu I) for about 100 s after burn-off. Working curves for aluminium for samples of different structure were very similar. (Auth.)

  6. Heterodyne detection at 300 GHz using neon indicator lamp glow discharge detector.

    Science.gov (United States)

    Aharon Akram, Avihai; Rozban, Daniel; Kopeika, Natan S; Abramovich, Amir

    2013-06-10

    A miniature neon indicator lamp, also known as a glow discharge detector (GDD), costing about 50 cents, was found to be an excellent room temperature terahertz radiation detector. Proof-of-concept 300 GHz heterodyne detection using GDD is demonstrated in this paper. Furthermore, a comparison to direct detection was carried out as well. Previous results with the GDD at 10 GHz showed 40 times better sensitivity using heterodyne detection compared to direct detection. Preliminary results at 300 GHz showed better sensitivity by a factor of 20 with only 56 μW local-oscillator power using heterodyne compared to direct detection. The higher the local-oscillator power (P(lo)), the better the sensitivity of the detector. Further improvement can be achieved by employing better quasi-optical design.

  7. Comparison of glow discharge cleaning with Taylor-type discharge cleaning on JFT-2

    International Nuclear Information System (INIS)

    Yokokura, Kenji; Matsuzaki, Yoshimi; Tani, Takashi

    1983-01-01

    Method of glow discharge cleaning (GDC) was applied to JFT-2 tokamak and the cleaning effect of GDC was compared with that of taylor-type discharge cleaning (TDC) on the same machin. Results show clearly their individual characteristics to remove light impurities. Their abilities of surface cleaning were compared each other by observing cleanliness of sample surfaces with a AES and by measuring decay times of produced gas pressures during discharge cleanings with a mass-analyser. It was shown that TDC method is better by several times than GDC method from a mass-analyser measurement. Moreover discharge cleaning time necessary to reduce light impurities in the normal plasma to a certain level was compared by monitoring time evolution of radiation loss power with a bolometer, and the time by TDC was only one fifth of that by GDC. The advantage of TDC may come from the excellently high hydrogen flux which interacts with the limiter and the wall. (author)

  8. Analysis of the neutral drag force in a dc glow discharge dusty plasma

    International Nuclear Information System (INIS)

    Thomas, Edward Jr.; Williams, Jeremiah

    2005-01-01

    In this paper, the authors report on a series of experiments that use carefully applied perturbations to a dust cloud to reproducibly investigate the formation of the microparticle cloud and the formation of dust cloud-plasma interface. Here, one micron diameter alumina microparticles are suspended in an argon dc glow discharge plasma. A perturbing voltage pulse is applied to the cathode, causing a momentary disruption in the confinement of the dust cloud. After the perturbation, the cloud reforms, typically with a central 'mass' and two 'streams' of particles that are flowing into the cloud from both sides. Through the use of stereoscopic particle image velocimetry (stereo-PIV), the complete three-dimensional velocity of the microparticles can be measured. The particles in the streams are used as test particles to characterize the forces acting upon the microparticles. Analysis of the experimental measurements suggests that the effective neutral drag force may be lower than expected

  9. Plasma sheath physics and dose uniformity in enhanced glow discharge plasma immersion ion implantation and deposition

    International Nuclear Information System (INIS)

    Li Liuhe; Li Jianhui; Kwok, Dixon T. K.; Chu, Paul K.; Wang Zhuo

    2009-01-01

    Based on the multiple-grid particle-in-cell code, an advanced simulation model is established to study the sheath physics and dose uniformity along the sample stage in order to provide the theoretical basis for further improvement of enhanced glow discharge plasma immersion ion implantation and deposition. At t=7.0 μs, the expansion of the sheath in the horizontal direction is hindered by the dielectric cage. The electron focusing effect is demonstrated by this model. Most of the ions at the inside wall of the cage are implanted into the edge of the sample stage and a relatively uniform ion fluence distribution with a large peak is observed at the end. Compared to the results obtained from the previous model, a higher implant fluence and larger area of uniformity are disclosed.

  10. Synthesis of Poly (Butyl Methacrylate/Butyl Acrylate) Highly Absorptive Resin Using Glow Discharge Electrolysis

    International Nuclear Information System (INIS)

    Li Yan; Yao Mengqi; Liao Ruirui; Yang Wu; Gao Jinzhang; Ren Jie

    2014-01-01

    A highly absorptive resin poly (butyl methacrylate (BMA)-co-butyl acrylate (BA)) was prepared by emulsion polymerization, which was initiated by glow discharge electrolysis plasma (GDEP). The effects of discharge voltage, discharge time, monomer ratio and the amounts of cross-linking agent were examined and discussed in detail. The chemical structure of the obtained resin was characterized by means of attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The optimal conditions were obtained as: discharge voltage was 600 V, discharge time was 8 min, the ratios of BMA:BA being 2:1 for chloroform and 3:1 for xylene, with 2% N, N'-methylenebis. Under optimal conditions, the oil absorbency was 70 g/g for chloroform and 46 g/g for xylene. Moreover, the absorptive dynamical behavior of the resulting resin was also investigated

  11. True random bit generators based on current time series of contact glow discharge electrolysis

    Science.gov (United States)

    Rojas, Andrea Espinel; Allagui, Anis; Elwakil, Ahmed S.; Alawadhi, Hussain

    2018-05-01

    Random bit generators (RBGs) in today's digital information and communication systems employ a high rate physical entropy sources such as electronic, photonic, or thermal time series signals. However, the proper functioning of such physical systems is bound by specific constrains that make them in some cases weak and susceptible to external attacks. In this study, we show that the electrical current time series of contact glow discharge electrolysis, which is a dc voltage-powered micro-plasma in liquids, can be used for generating random bit sequences in a wide range of high dc voltages. The current signal is quantized into a binary stream by first using a simple moving average function which makes the distribution centered around zero, and then applying logical operations which enables the binarized data to pass all tests in industry-standard randomness test suite by the National Institute of Standard Technology. Furthermore, the robustness of this RBG against power supply attacks has been examined and verified.

  12. Sputtering and emission intensity of cast irons with different metallurgical structures in a Grimm glow lamp

    International Nuclear Information System (INIS)

    Fujita, M.; Kashima, J.; Naganuma, K.

    1981-01-01

    The cathodic sputtering and emission intensities for the white, gray and malleable cast irons in the Grimm glow lamp are discussed. The intensities of the Fe 247.98-nm line for the samples of the three types depend linearly on the electrical power but the slopes of the plots differ. The intensity of the carbon line at 247.86 nm for malleable cast iron is weaker than those for the others. Sputtering is influenced by the form of the graphite, which can lead to distortion of the electrical field. Graphite on malleable cast iron is sputtered not only as atomic carbon but also as moieties containing several carbon atoms. The higher the supplied voltage, the shorter the time for the intensities of the Fe I and C I lines to reach constant values. (Auth.)

  13. Degradation of m-dihydroxybenzene by contact glow discharge electrolysis in aqueous

    International Nuclear Information System (INIS)

    Gai, Ke; Qi, Huili; Ma, Dongping; Wang, Chunlin

    2013-01-01

    This paper reported the degradation of m-dihydroxybenzene aqueous solution with contact Glow Discharge Electrolysis. The rate of degradation in different conditions such as pH, H 2 O 2 , Fe 2+ , methanol, and other affecting factors were studied. The results showed that there is faster removal rate when the solution is in a relatively higher acidity; H 2 O 2 can improve the efficiency rate. Fe 2+ can promote reaction, but radical elimination agent of methanol will decrease the rate of the reaction. On the basis of analyzing the ultraviolet (UV) spectra of the solution and the intermediate products from High Performance Liquid Chromatography-Mass Spectrum (HPLC-MS), reaction pathway was proposed.

  14. Charged particle emission effects on the characteristics of glow discharges with oscillating electrons

    CERN Document Server

    Nikulin, S P

    2001-01-01

    One discusses the effect of selection of charged particles on conditions to maintain and the characteristics of a glow discharge with oscillating electrons. It is shown that there is a pressure dependent optimal level of ion selection when the energy efficiency of ion source reaches its maximum value. It is determined that departure of fast ionizing electrons affects negatively the discharge maintenance wile emission of slow plasma electrons may promote maintenance of a discharge high current shape. It is shown that high efficient electron emission without violation of a discharge stability may take place in a magnetic field due to different nature of spatial distributions of fast and slow particles in discharges with electron oscillation

  15. Compositional characterisation of rare earth magnet materials by glow discharge quadrupole mass spectrometry

    International Nuclear Information System (INIS)

    Reddy, M.A.; Shekhar, R.; Kumar, Sunil Jai

    2014-01-01

    In this paper, glow discharge quadrupole mass spectrometric (GD-QMS) studies on Sm-Pr-Co compound magnetic materials are reported. The composition of these magnetic materials produced from different manufacturing routes (imported, indigenous) was determined. The results are compared with the results obtained by an alternative analytic technique, inductively coupled plasma atomic emission spectrometry (ICP-AES), after complete dissolution of the material in the appropriate acids. For perfectly homogeneous material both the wet chemical method and direct solid analysis method should give the same result. A close examination of both the results indicates that for imported materials the values obtained by wet chemical method and direct solid method are in close agreement. This indicates that the imported (solid) material is highly homogeneous. For indigenous materials, it shows a large difference in the values of Co and Sm. This reveals that the solid material prepared is not as homogenous as the imported materials

  16. Microelectrode-assisted low-voltage atmospheric pressure glow discharge in air

    Science.gov (United States)

    Liu, Wenzheng; Zhao, Shuai; Niu, Jiangqi; Chai, Maolin

    2017-09-01

    During the process of discharge, appropriately changing the paths corresponding to electric field lines and the field strength distribution along these paths, as well as increasing the number of initial electrons, can effectively enhance the uniformity of discharge and inhibit the formation of filamentary discharge. A method is proposed that uses a microelectrode to initiate the macroscopic discharge phenomenon. An asymmetric structure was designed comprising a single electrode of carbon fiber; this electrode structure is of helical-contact type. Benefitting from the special electric field distribution and the microdischarge process, a three-dimensional atmospheric pressure glow discharge was achieved in air, characterized by low discharge voltage, low energy consumption, good diffusion performance, and less ozone generation. The plasma studied is uniform and stable with good diffusion characteristics and low levels of contaminants and hence has potential applications in the field of air purification.

  17. Effect of silane dilution on intrinsic stress in glow discharge hydrogenated amorphous silicon films

    Science.gov (United States)

    Harbison, J. P.; Williams, A. J.; Lang, D. V.

    1984-02-01

    Measurements of the intrinsic stress in hydrogenated amorphous silicon (a-Si : H) films grown by rf glow discharge decomposition of silane diluted to varying degrees in argon are presented. Films are found to grow under exceedingly high compressive stress. Low values of macroscopic film density and low stress values are found to correlate with high growth rate. An abrupt drop in stress occurs between 2 and 3% silane at precisely the point where columnar growth morphology appears. No corresponding abrupt change is noted in density, growth rate, or plasma species concentrations as determined by optical emissioin spectroscopy. Finally a model of diffusive incorporation of hydrogen or some gaseous impurity during growth into the bulk of the film behind the growing interface is proposed to explain the results.

  18. Glow discharge-deposited amorphous silicon films for low-cost solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Grabmaier, J G; Plaettner, R D; Stetter, W [Siemens A.G., Muenchen (Germany, F.R.). Forschungslaboratorien

    1980-01-01

    Due to their high absorption constant, glow discharge-deposited amorphous silicon (a-Si) films are of great interest for low-cost solar cells. Using SiH/sub 4/ and SiX/sub 4//H/sub 2/ (X = Cl or F) gas mixtures in an inductively or capacitively excited reactor, a-Si films with thicknesses up to several micrometers were deposited on substrates of glass, silica and silicon. The optical and electrical properties of the films were determined by measuring the IR absorption spectra, dark conductivity, photoconductivity, and photoluminescence. Hydrogen, chlorine, or fluorine were incorporated in the films in order to passivate dangling bonds in the amorphous network.

  19. Control of discharge conditions to reduce hydrogen content in low Z films produced with DC glow

    International Nuclear Information System (INIS)

    Natsir, M.; Sagara, A.; Tsuzuki, K.; Tsuchiya, B.; Hasegawa, Y.; Motojima, O.

    1995-09-01

    Boronization at near room temperature has been performed in plasma processing teststand (PPT) by using a 5 % diborane gases B 2 H 6 in He on electrically floating or unfloating Al samples under various conditions on DC glow discharge power or total gas pressure. The hydrogen concentration was analyzed by using elastic recoil detection method (ERD) and a new modified normalizing technique with Rutherford back scattering (RBS). Results showed that a high growth rate of film formation and floating surface were effective in reducing hydrogen concentration in B films. This result was in good agreement with earlier measurements of H with flash filament (FF) desorption method. In particular the H/B ratio was reduced by decreasing ions but increasing radicals for B film formation. (author)

  20. Spatially Resolved Gas Temperature Measurements in an Atmospheric Pressure DC Glow Microdischarge with Raman Scattering

    Science.gov (United States)

    Belostotskiy, S.; Wang, Q.; Donnelly, V.; Economou, D.; Sadeghi, N.

    2006-10-01

    Spatially resolved rotational Raman spectroscopy of ground state nitrogen N2(X^1σg^+) was used to measure the gas temperature (Tg) in a nitrogen dc glow microdischarge (gap between electrodes d˜500 μm). An original backscattering, confocal optical system was developed for collecting Raman spectra. Stray laser light and Raleigh scattering were blocked by using a triple grating monochromator and spatial filters, designed specifically for these experiments. The optical system provided a spatial resolution of electrodes, Tg increased linearly with jd, reaching 500 K at 1000 mA/cm^2 jd for a pressure of 720 Torr. Spatially resolved gas temperature measurements will also be presented and discussed in combination with a mathematical model for gas heating in the microplasma. This work is supported by DoE/NSF.