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Sample records for non-conventional fishbone instabilities

  1. Fishbone Instability Excited by Barely Trapped Electrons

    Institute of Scientific and Technical Information of China (English)

    WANG Zhong-Tian; LONG Yong-Xing; DONG Jia-Qi; WANG Long; Fulvio Zonca

    2006-01-01

    Fishbone instability excited by barely trapped suprathermal electrons (BTSEs) in tokamaks is investigated theoretically. The frequency of the mode is found to close to procession frequency of BTSEs. The growth rate of the mode is much smaller than that of the ideal magnetohytrodynamic (MHD) internal kink mode that is in contrast to the case of trapped ion driven fishbone instability. The analyses also show that spatial density gradient reversal is necessary for the instability. The correlation of the results with experiments is discussed.

  2. Observation of Fishbone-Like Instabilities Excited by Energetic Electrons on the HL-2A Tokamak

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; DENG Wei; YANG Qing-Wei; DING Xuan-Wong; LIU Yi; YUAN Guo-Liang; ZHANG Yi-Po; DONG Yun-Bo; SONG Xian-Ying; ZHOU Jun; SONG Xian-Ming

    2008-01-01

    Strong burst of an internal kink mode is observed on the HL-2A tokamak. Features of the fishbone-like mode are presented. The fishbone-like instabilities can be driven during electron cyclotron resonance heating (ECRH) and can be excited on the high field side (HFS) by ECRH. It is found for the first time that the modes also present themselves on the low field side (LFS) during ECRH. Experiments show that the energetic electrons with energy of 35-70 keV play a dominant role in the excitation mechanism, and the experimental results are also consistent with our calculation ones.

  3. Dynamics between the fishbone instability and nonlocal transient transport in HL-2A NBI plasmas

    Science.gov (United States)

    Chen, W.; Xu, Y.; Ding, X. T.; Shi, Z. B.; Jiang, M.; Zhong, W. L.; Ji, X. Q.; HL-2A Team

    2016-04-01

    Understanding of nonlocal electron heat transport is of key importance for current magnetic confinement fusion research. Global nonlocal response presents a fundamental challenge to the standard anomalous transport model based on local microinstabilities and turbulence. Here, we present for the first time a new nonlocal phenomenon triggered by the fishbone instability in HL-2A neutral beam injection plasmas. Rapid core heating leads to a simultaneous decrease in temperature at the plasma edge. The effect reveals fast anomalous transport of core heat pulses to the plasma edge, not compatible with diffusive time scales. More importantly, Δ {{T}\\text{e}}/text{e}}> variations at different locations are restricted by the intensity of magnetic fluctuations. The Δ {{T}\\text{e}}/text{e}}> and {{≤ft(δ {{B}θ}\\right)}\\text{rms}} form two types of hysteresis loops at two sides of the inversion radius. The ECEIs show that the 2D mode structure of the fishbone is intensive shearing/spiraling during the nonlocal transport. Experimental results suggest that magnetic perturbation, long-range correlation, mesoscale structure and E× B flow play crucial roles in the nonlocal response. The Hurst exponent and auto-correlation coefficient indicate that the nonlocal transport is potentially linked to the self-organized critical (SOC) dynamics. This work will be beneficial for understanding of the plasma dynamics in future fusion reactors.

  4. Observation of the double e-fishbone instability in HL-2A ECRH/ECCD plasmas

    Science.gov (United States)

    Jiang, M.; Ding, X. T.; Shi, Z. B.; Chen, W.; Yu, L. M.; Dong, J. Q.; Xu, Y.; Liu, Y.; Yuan, B. S.; Zhong, W. L.; Zhou, Y.; Li, Y. G.; Yang, Z. C.; Shi, P. W.; Dong, Y. B.; Yang, Q. W.; Duan, X. R.

    2017-02-01

    Two m/n = 1/1 kink modes excited by energetic electrons (called double e-fishbone) have been observed near the q = 1 flux surfaces in the HL-2A discharges. The negative magnetic central shear configuration was achieved with localized electron cyclotron resonance heating and electron cyclotron current drive during plasma current ramp-up. The features of the modes have been first shown by advanced 2D electron cyclotron emission imaging (ECEI) system. From ECEI, two m/n = 1/1 modes propagating in the opposite directions poloidally have been clearly observed. These modes can be found only in low density discharge, and their frequencies are close to the precessional frequency of the trapped energetic electrons. More interestingly, the thermal energy transfer between the two modes was revealed by this new diagnostic, which is found to be related to the nonlinear interaction of the two modes and local electron thermal transport.

  5. Inventory non-conventional gas

    Energy Technology Data Exchange (ETDEWEB)

    Muntendam-Bos, A.G.; Wassing, B.B.T.; Ter Heege, J.H.; Van Bergen, F.; Schavemaker, Y.A.; Van Gessel, S.F.; De Jong, M.L.; Nelskamp, S.; Van Thienen-Visser, K.; Guasti, E.; Van den Belt; Marges, V.C. [TNO Built Environment and Geosciences, Utrecht (Netherlands)

    2009-10-15

    This report describes the results of the inventory for each non-conventional gas resource expected to be present in the Netherlands, which are: Tight Gas, Shallow gas, Coal bed Methane (CBM), Shale gas, Basin Centered Gas, Aquifer Gas and Stratigraphic traps.

  6. Electron fishbones: Theory and experimental evidence

    CERN Document Server

    Zonca, F; Cardinali, A; Chen, L; Dong, J -Q; Long, Y -X; Milovanov, A V; Romanelli, F; Smeulders, P; Wang, L; Wang, Z -T; Castaldo, C; Cesario, R; Giovannozzi, E; Marinucci, M; Ridolfini, V Pericoli

    2007-01-01

    We discuss the processes underlying the excitation of fishbone-like internal kink instabilities driven by supra-thermal electrons generated experimentally by different means: Electron Cyclotron Resonance Heating (ECRH) and by Lower Hybrid (LH) power injection. The peculiarity and interest of exciting these electron fishbones by ECRH only or by LH only is also analyzed. Not only the mode stability is explained, but also the transition between steady state nonlinear oscillations to bursting (almost regular) pulsations, as observed in FTU, is interpreted in terms of the LH power input. These results are directly relevant to the investigation of trapped alpha particle interactions with low-frequency MHD modes in burning plasmas: in fact, alpha particles in reactor relevant conditions are characterized by small dimensionless orbits, similarly to electrons; the trapped particle bounce averaged dynamics, meanwhile, depends on energy and not mass.

  7. Theory and modeling of electron fishbones

    Science.gov (United States)

    Vlad, G.; Fusco, V.; Briguglio, S.; Fogaccia, G.; Zonca, F.; Wang, X.

    2016-10-01

    Internal kink instabilities exhibiting fishbone like behavior have been observed in a variety of experiments where a high energy electron population, generated by strong auxiliary heating and/or current drive systems, was present. After briefly reviewing the experimental evidences of energetic electrons driven fishbones, and the main results of linear and nonlinear theory of electron fishbones, the results of global, self-consistent, nonlinear hybrid MHD-Gyrokinetic simulations will be presented. To this purpose, the extended/hybrid MHD-Gyrokinetic code XHMGC will be used. Linear dynamics analysis will enlighten the effect of considering kinetic thermal ion compressibility and diamagnetic response, and kinetic thermal electrons compressibility, in addition to the energetic electron contribution. Nonlinear saturation and energetic electron transport will also be addressed, making extensive use of Hamiltonian mapping techniques, discussing both centrally peaked and off-axis peaked energetic electron profiles. It will be shown that centrally peaked energetic electron profiles are characterized by resonant excitation and nonlinear response of deeply trapped energetic electrons. On the other side, off-axis peaked energetic electron profiles are characterized by resonant excitation and nonlinear response of barely circulating energetic electrons which experience toroidal precession reversal of their motion.

  8. Craftsman Breathes Life into Fishbones

    Institute of Scientific and Technical Information of China (English)

    WuWei

    2004-01-01

    The first time I went to Fan Da's house, I was amazed by the varieties of animals and insects on his bookshelves. Actually, they are not real critters, but fishbone sculptures created by the one-of-a-kind artist over the past decade or so.

  9. Investigation of Surfaces after Non Conventional Machining

    Science.gov (United States)

    Micietova, Anna; Neslusan, Miroslav; Cillikova, Maria

    2016-12-01

    This paper deals with analysis of surface integrity of steel after electro discharge machining (EDM), water jet machining, (WJM) laser beam machining (LBM) and plasma beam machining (PBM). The paper discusses surface integrity expressed in surface roughness, sample precision expressed in perpendicularity deviation as well as stress state. This study also demonstrates influence of the various non-conventional methods on structure transformations and reports about sensitivity of the different non-conventional methods of machining with regard to variable thickness of machined samples.

  10. Control of non-conventional synchronous motors

    CERN Document Server

    Louis, Jean-Paul

    2013-01-01

    Classical synchronous motors are the most effective device to drive industrial production systems and robots with precision and rapidity. However, numerous applications require efficient controls in non-conventional situations. Firstly, this is the case with synchronous motors supplied by thyristor line-commutated inverters, or with synchronous motors with faults on one or several phases. Secondly, many drive systems use non-conventional motors such as polyphase (more than three phases) synchronous motors, synchronous motors with double excitation, permanent magnet linear synchronous motors,

  11. Non-conventional mesons at PANDA

    Science.gov (United States)

    Giacosa, Francesco

    2015-04-01

    Non-conventional mesons, such as glueballs and tetraquarks, will be in the focus of the PANDA experiment at the FAIR facility. In this lecture we recall the basic properties of QCD and describe some features of unconventional states. We focus on the search of the not-yet discovered glueballs and the use of the extended Linear Sigma Model for this purpose, and on the already discovered but not-yet understood X, Y, Z states.

  12. Non conventional engines; Moteurs non conventionnels

    Energy Technology Data Exchange (ETDEWEB)

    Descombes, G. [Conservatoire National des Arts et Metiers (CNAM), 75 - Paris (France)]|[Paris-6 Univ. Pierre-et-Marie-Curie, 75 (France). Laboratoire de mecanique physique; Magnet, J.L. [SEMT Pielstick, 93 - Saint Denis (France)]|[Conservatoire National des Arts et Metiers (CNAM), 75 - Paris (France)

    1998-07-01

    The extraordinary realizations of the last century in words of piston engines, are always current events at the dawn of 2000. This paper deals with three types of non conventional engines: the reciprocating internal combustion engines (opposed piston engines, oscillating piston engines, variable geometry piston engines...); the internal combustion rotary engines(Wankel engine, blade engines...) and external combustion reciprocating engines (historical aspects, conception, thermodynamics and market). (A.L.B.)

  13. Non conventional fuel resources in rural India

    Energy Technology Data Exchange (ETDEWEB)

    Dixit, G.; Dixit, S.; Tiwari, S.

    2006-03-15

    In India there is a shortage of energy resources. The conventional sources are incapable to mitigate this problem by providing sufficient amount of energy. The crisis is gradually becoming more acute particularly in the countryside thus hampering the economic growth. To deal with this problem some new strategies have been envisaged. Generation of energy to meet daily requirement from non-conventional sources is one of the steps in this regard. With the increasing popularity of biogas plants in rural as well as in urban areas of India, it has become essential to find various location specific organic substances that can be used as feed material in biogas plant. In this study we have concentrated on use of cow dung and water hyacinth as feed material in biogas plants. The objective of the study is to assess the suitability of using mixture of cow dung and water hyacinth as feed material in biogas plants. Attempt has been made to find out the optimum proportion of cow dung and water hyacinth. The 1:1 mixture of cow dung and water hyacinth is the optimum proportion as per the study conducted. (author)

  14. Biocatalysis in non-conventional media : kinetic and thermodynamic aspects

    NARCIS (Netherlands)

    Vermuë, M.

    1995-01-01

    During the past decade biocatalysis in non-conventional media has gained a lot of interest. Especially in the field of bio-organic synthesis, where poorly water-soluble substrates and products are involved, these media are very attractive.

    Non-conventional media generally consist of

  15. Language Revolt in Paradise: Recent Indonesian Non-Conventional Expressions

    Directory of Open Access Journals (Sweden)

    Yazid Basthomi

    2009-01-01

    Full Text Available Language is dynamic and, accordingly, language change is bound to occur. This article analyzes few recent Indonesian non-conventional expressions as properties which potentially motivate some changes in Bahasa Indonesia (Indonesian. Since the term “non-conventional” has to do with the notion of “convention”, which is central to Saussurean linguistics, the analysis is carried out by means of Saussure’s linguistic views. The analysis shows that the non-conventional expressions can be well accounted for using Saussure’s theoretical propositions. However, as to why Indonesians come up with the non-conventional expressions is beyond pure Saussure’s linguistic concepts. The article also touches upon the idea that the issue about non-conventional expressions (which may be deemed grammatical aberrations poses a challenge to language planners.

  16. Non-conventional Superconductors and diluted Ising Model

    CERN Document Server

    Ni, Xuan Zhong

    2016-01-01

    This paper demonstrates that the results of a Monte Carlo simulation of a diluted 2D Ising antiferromagnetic system corresponds with the phase diagram for non conventional superconductors. An energy gap of this system is defined. We also find a strange phenomenon that when the lattice size of simulation increased the crystal structure becomes more like quasi crystal at the low temperature.

  17. Parametric Investigations of Non-Conventional Hall Thruster

    Energy Technology Data Exchange (ETDEWEB)

    Raitses, Y.; Fisch, N.J.

    2001-01-12

    Hall thrusters might better scale to low power with non-conventional geometry. A 9 cm cylindrical, ceramic-channel, Hall thruster with a cusp-type magnetic field distribution has been investigated. It exhibits discharge characteristics similar to conventional coaxial Hall thrusters, but does not expose as much channel surface. Significantly, its operation is not accompanied by large amplitude discharge low frequency oscillations.

  18. Non-Conventional Methodologies in the Synthesis of 1-Indanones

    Directory of Open Access Journals (Sweden)

    Manuela Oliverio

    2014-04-01

    Full Text Available 1-Indanones have been successfully prepared by means of three different non-conventional techniques, namely microwaves, high-intensity ultrasound and a Q-tube™ reactor. A library of differently substituted 1-indanones has been prepared via one-pot intramolecular Friedel-Crafts acylation and their efficiency and “greenness” have been compared.

  19. Mineral composition of non-conventional leafy vegetables.

    Science.gov (United States)

    Barminas, J T; Charles, M; Emmanuel, D

    1998-01-01

    Six non-conventional leafy vegetables consumed largely by the rural populace of Nigeria were analyzed for mineral composition. Mineral contents appeared to be dependent on the type of vegetables. Amaranthus spinosus and Adansonia digitata leaves contained the highest level of iron (38.4 mg/100 g and 30.6 mg/100 g dw, respectively). These values are low compared to those for common Nigerian vegetables but higher than those for other food sources. All the vegetables contained high levels of calcium compared to common vegetables, thus they could be a rich source of this mineral. Microelement content of the leaves varied appreciably. Zinc content was highest in Moringa oleifera, Adansonia digitata and Cassia tora leaves (25.5 mg/100 g, 22.4 mg/100 g and 20.9 mg/100 g dw, respectively) while the manganese content was comparatively higher in Colocasia esculenta. The concentrations of the mineral elements in the vegetables per serving portion are presented and these values indicate that the local vegetables could be valuable and important contributors in the diets of the rural and urban people of Nigeria. The mean daily intake of P, Mg, Ca, Fe, Cu and Zn were lower than their recommended dietary allowances (RDAs). However, the manganese daily intake was found not to differ significantly (p = 0.05) from the RDA value.

  20. How non-conventional feedstocks will affect aromatics technologies

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, E. [Clariant Produkte (Deutschland) GmbH, Muenchen (Germany)

    2013-11-01

    The abundance of non-conventional feedstocks such as coal and shale gas has begun to affect the availability of traditional base chemicals such as propylene and BTX aromatics. Although this trend is primarily fueled by the fast growing shale gas economy in the US and the abundance of coal in China, it will cause the global supply and demand situation to equilibrate across the regions. Lower demand for gasoline and consequently less aromatics rich reformate from refineries will further tighten the aromatics markets that are expected to grow at healthy rates, however. Refiners can benefit from this trend by abandoning their traditional fuel-oriented business model and becoming producers of petrochemical intermediates, with special focus on paraxylene (PX). Cheap gas from coal (via gasification) or shale reserves is an advantaged feedstock that offers a great platform to make aromatics in a cost-competitive manner, especially in regions where naphtha is in short supply. Gas condensates (LPG and naphtha) are good feedstocks for paraffin aromatization, and methanol from coal or (shale) gas can be directly converted to BTX aromatics (MTA) or alkylated with benzene or toluene to make paraxylene. Most of today's technologies for the production and upgrading of BTX aromatics and their derivatives make use of the unique properties of zeolites. (orig.)

  1. Fishbone Diagrams: Organize Reading Content with a "Bare Bones" Strategy

    Science.gov (United States)

    Clary, Renee; Wandersee, James

    2010-01-01

    Fishbone diagrams, also known as Ishikawa diagrams or cause-and-effect diagrams, are one of the many problem-solving tools created by Dr. Kaoru Ishikawa, a University of Tokyo professor. Part of the brilliance of Ishikawa's idea resides in the simplicity and practicality of the diagram's basic model--a fish's skeleton. This article describes how…

  2. Fishbone Diagrams: Organize Reading Content with a "Bare Bones" Strategy

    Science.gov (United States)

    Clary, Renee; Wandersee, James

    2010-01-01

    Fishbone diagrams, also known as Ishikawa diagrams or cause-and-effect diagrams, are one of the many problem-solving tools created by Dr. Kaoru Ishikawa, a University of Tokyo professor. Part of the brilliance of Ishikawa's idea resides in the simplicity and practicality of the diagram's basic model--a fish's skeleton. This article describes how…

  3. Thoracic spinal epidural abscess caused by fishbone perforation

    Science.gov (United States)

    Chen, Jian-Min; Wang, Zhi-Yong; Ni, Guo-Xin

    2016-01-01

    Abstract Rationale: Ingestion of a fishbone is a common cause of esophageal injury, but spinal epidural abscess (SEA) is a rare condition due to the esophageal penetration by a swallowed fishbone. Prompt diagnosis can be seldom made owing to incomplete patient history taking and difficulties in imaging evidence identification. Patient concerns: We describe the case of a 62-year-old woman who was stuck in her throat by a fishbone, and complained of back pain, paresis of the lower limbs and fever, successively. To our knowledge, this is the first case report that we know of thoracic SEA caused by fishbone perforation. Diagnoses: About 20 days after the onset of severe back pain, she was diagnosed with SEA based on the clinical presentation and imaging findings. Interventions: Antibiotic therapy and rehabilitation therapy were carried out afterwards. However, due to exacerbation of her condition, surgical intervention had to be taken eventually. Outcomes: It is quite unfortunate for this patient to have a poor prognosis due to a delayed diagnosis and an improper management. Lessons: A number of lessons can be learnt from this case. PMID:27930507

  4. Fast Ion Effects on Fishbones and n=1 Kinks in JET Simulated by a Non-perturbative NOVA-KN Code

    Energy Technology Data Exchange (ETDEWEB)

    N.N. Gorelenkov; C.Z. Cheng; V.G. Kiptily; M.J. Mantsinen; S.E. Sharapov; the JET-EFDA Contributors

    2004-10-28

    New global non-perturbative hybrid code, NOVA-KN, and simulations of resonant type modes in JET [Joint European Torus] plasmas driven by energetic H-minority ions are presented. The NOVA-KN code employs the ideal-MHD description for the background plasma and treats non-perturbatively the fast particle kinetic response, which includes the fast ion finite orbit width (FOW) effect. In particular, the n = 1 fishbone mode, which is in precession drift resonance with fast ions, is studied. The NOVA-KN code is applied to model an n = 1 (f = 50-80kHz) MHD activity observed recently in JET low density plasma discharges with high fast ion (H-minority) energy content generated during the ion cyclotron resonance heating (ICRH). This n = 1 MHD activity is interpreted as the instability of the n = 1 precession drift frequency fishbone modes.

  5. Refinement of the $n-\\alpha$ and $p-\\alpha$ fish-bone potential

    CERN Document Server

    Smith, E; Papp, Z

    2012-01-01

    The fishbone potential of composite particles simulates the Pauli effect by nonlocal terms. We determine the $n-\\alpha$ and $p-\\alpha$ fish-bone potential by simultaneously fitting to the experimental phase shifts. We found that with a double Gaussian parametrization of the local potential can describe the $n-\\alpha$ and $p-\\alpha$ phase shifts for all partial waves.

  6. The Application of Fishbone Diagram Analisis to Improve School Quality

    Directory of Open Access Journals (Sweden)

    Slameto Slameto

    2016-06-01

    Full Text Available The research problems are: 1 What steps are to take in a program development aimed at improving the quality of school using a fishbone analysis? 2 Is the program model using fishbone analysis  effective and efficient in meeting the school’s needs to improve its quality? This is research and developmental which comprises 3 phases, namely Preliminary Study, Model Development, and Evaluation/Model Testing. The qualitative data come from the input of management experts and the result of interviews/FGD with stakeholders. The quantitative data are obtained from the assessment of management experts on the product draft, the observation sheets for the field study on the standards of education, and the try out. Data analisis on the validation result uses a descriptive analysis technique. Data from the questionnaire are analyzed by descriptive statistical technique. The results are: 1 the developmental steps in the school quality improvement program by way of fish bone analysis have gone through 6 phases, 2 the research product using fish bone diagram has proved to be simple, applicable, important, controllable, as well as adaptable. Furthermore, it is communicable, so that it has been effective and efficient in meeting the school’s needs for making its educational quality improved.

  7. One-dimensional photonic crystal fishbone hybrid nanocavity with nanoposts

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Tsan-Wen; Lin, Pin-Tso; Lee, Po-Tsung, E-mail: potsung@mail.nctu.edu.tw [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Rm. 413 CPT Building, 1001 Ta-Hsueh Road, Hsinchu 30010, Taiwan (China)

    2014-05-12

    We propose and investigate a one-dimensional photonic crystal (PhC) fishbone (FB) hybrid nanocavity lying on silver substrate with a horizontal air slot. With very few PhC periods, the confined transverse-magnetic, TM{sub 10} hybrid mode concentrated within the air slot shows high quality factor over effective mode volume ratio larger than 10{sup 5}λ{sup −3}. Most importantly, this FB hybrid nanocavity allows formation of low-index nanoposts within the air slot without significantly affecting the mode properties. These nanoposts guarantee the structural stabilities under different environmental perturbations. Furthermore, capabilities of our proposed design in serving as optical sensors and tweezers for bio-sized nanoparticles are also investigated.

  8. Analysis of Non-Conventional Hybrid MOSFET Structure for Gate Leakage Current

    Directory of Open Access Journals (Sweden)

    RANA Ashwani K.

    2011-10-01

    Full Text Available A non-conventional hybrid MOSFET (HMOSstructure has been proposed to reduce the gate leakagecurrent. This non-conventional hybrid MOSFET consistsof source/drain-to-gate non-overlap region and high-kgate stack. The gate leakage behaviour of HMOS hasbeen investigated with the help of compact analyticalmodel, which is backed by Sentaurus Simulation. Ourmodel sustains a very good agreement between the modeland TCAD result. It is found that HMOS structure hasreduced the gate leakage current to great extent ascompared to conventional overlapped MOSFETstructure.

  9. Non-conventional methods and media for the activation and manipulation of carbon nanoforms.

    Science.gov (United States)

    Vázquez, Ester; Giacalone, Francesco; Prato, Maurizio

    2014-01-07

    Very often, chemical transformations require tedious and long procedures, which, sometimes, can be avoided using alternative methods and media. New protocols, enabling us to save time and solvents, allow us also to explore new reaction profiles. This Tutorial Review focuses on the physical and chemical behavior of carbon nanoforms, CNFs (fullerenes, nanotubes, nanohorns, graphene, etc.) when non-conventional methods and techniques, such as microwave irradiation, mechano-chemistry or highly ionizing radiations are employed. In addition, the reactivity of CNFs in non-conventional media such as water, fluorinated solvents, supercritical fluids, or ionic liquids is also discussed.

  10. APPLICATION OF FISHBONE DIAGRAM TO DETERMINE THE RISK OF AN EVENT WITH MULTIPLE CAUSES

    OpenAIRE

    Gheorghe ILIE; Carmen Nadia CIOCOIU

    2010-01-01

    Fishbone diagram (also known as Ishikawa diagram) was created with the goal of identifying and grouping the causes which generate a quality problem. Gradually, the method has been used also to group in categories the causes of other types of problems which an organization confronts with. This made Fishbone diagram become a very useful instrument in risk identification stage. The article proposes to extend the applicability of the method by including in the analysis the probabilities and the i...

  11. Microbial Terroir in Chilean Valleys: Diversity of Non-conventional Yeast

    Science.gov (United States)

    Jara, Carla; Laurie, V. Felipe; Mas, Albert; Romero, Jaime

    2016-01-01

    In this study, the presence of non-conventional yeast associated with vineyards located between latitudes 30°S and 36°S was examined, including the valleys of Limarí, Casablanca, Maipo, Colchagua, Maule, and Itata. The microbial fingerprinting in each valley was examined based on the specific quantification of yeast of enological interest. Grape–berries were sampled to evaluate the presence and load of non-conventional yeast with enological potential, such as Metschnikowia, Hanseniaspora, Torulaspora, Debaryomyces, Meyerozyma, and Rhodotorula. These yeasts were present in all vineyards studied but with varying loads depending on the valley sampled. No identical fingerprints were observed; however, similarities and differences could be observed among the microbial profiles of each valley. A co-variation in the loads of Metschnikowia and Hanseniaspora with latitude was observed, showing high loads in the Casablanca and Itata valleys, which was coincident with the higher relative humidity or rainfall of those areas. Non-conventional yeasts were also isolated and identified after sequencing molecular markers. Potentially good aromatic properties were also screened among the isolates, resulting in the selection of mostly Metschnikowia and Hanseniaspora isolates. Finally, our results suggest that microbial terroir might be affected by climatic conditions such as relative humidity and rainfall, especially impacting the load of non-conventional yeast. In this study, the microbial fingerprint for yeast in Chilean vineyards is reported for the first time revealing an opportunity to study the contribution of this assembly of microorganisms to the final product. PMID:27242693

  12. Advanced Techniques for Reservoir Simulation and Modeling of Non-Conventional Wells

    Energy Technology Data Exchange (ETDEWEB)

    Durlofsky, Louis J.

    2000-08-28

    This project targets the development of (1) advanced reservoir simulation techniques for modeling non-conventional wells; (2) improved techniques for computing well productivity (for use in reservoir engineering calculations) and well index (for use in simulation models), including the effects of wellbore flow; and (3) accurate approaches to account for heterogeneity in the near-well region.

  13. Use of non-conventional yeast improves the wine aroma profile of Ribolla Gialla

    NARCIS (Netherlands)

    Dashko, Sofia; Zhou, Nerve; Tinta, Tinkara; Sivilotti, Paolo; Lemut, Melita Sternad; Trost, Kajetan; Gamero, Amparo; Boekhout, Teun; Butinar, Lorena; Vrhovsek, Urska; Piskur, Jure

    Consumer wine preferences are changing rapidly towards exotic flavours and tastes. In this work, we tested five non-conventional yeast strains for their potential to improve Ribolla Gialla wine quality. These strains were previously selected from numerous yeasts interesting as food production

  14. Use of non-conventional yeast improves the wine aroma profile of Ribolla Gialla

    NARCIS (Netherlands)

    Dashko, Sofia; Zhou, Nerve; Tinta, Tinkara; Sivilotti, Paolo; Lemut, Melita Sternad; Trost, Kajetan; Gamero, Amparo; Boekhout, Teun; Butinar, Lorena; Vrhovsek, Urska; Piskur, Jure

    2015-01-01

    Consumer wine preferences are changing rapidly towards exotic flavours and tastes. In this work, we tested five non-conventional yeast strains for their potential to improve Ribolla Gialla wine quality. These strains were previously selected from numerous yeasts interesting as food production candid

  15. Advanced Techniques for Reservoir Simulation and Modeling of Non-Conventional Wells

    Energy Technology Data Exchange (ETDEWEB)

    Durlofsky, Louis J.; Aziz, Khalid

    2001-08-23

    Research results for the second year of this project on the development of improved modeling techniques for non-conventional (e.g., horizontal, deviated or multilateral) wells were presented. The overall program entails the development of enhanced well modeling and general simulation capabilities. A general formulation for black-oil and compositional reservoir simulation was presented.

  16. Non-Conventional Plasma Assisted Catalysts for Diesel Exhaust Treatment: A Case Study

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper reports the application of pulse discharges along with catalysts in treating the exhaust gas at higher temperatures. In the present work a plasma reactor, filled with catalysts, called as plasma catalytic reactor, is studied for removal of oxides of nitrogen, total hydrocarbons and carbon monoxide. The experiments are conducted on an actual diesel engine exhaust at no-load and at different temperatures starting from room temperature to 300℃. The removal efficiencies of these pollutants are studied. The experiments are carried out with both conventional and non-conventional catalysts. The idea is to explore the pollutant removal efficiency characteristics by non-conventional catalysts. The efficiency results are compared with that of conventional catalysts. The experiments are carried out at a constant pulse repetition rate of 120 pps. Both pellet and honeycomb type catalysts are used in the study.

  17. Evaluation of a layer diet formulated from non-conventional feedingstuffs.

    Science.gov (United States)

    Ravindran, V

    1995-03-01

    1. A layer diet, the formulation of which was based on several non-conventional feedingstuffs, was evaluated at the research station and under small farm conditions in Sri Lanka. The new feedingstuffs included finger millet, rice polishings, rubber seed meal, cassava leaf meal, ipil ipil leaf meal and dried poultry manure. A commercial mash, that is normally used on the farm, served as the control. 2. The performance and egg quality characteristics were similar between the test and control diets, the only exception being the egg yolk colour which was improved (P < 0.05) by feeding the test diet. Food cost per dozen eggs was lowered by feeding the test diet. 3. It is possible to formulate layer diets using non-conventional feedingstuffs, achieve acceptable production and lower the food costs under small farm conditions in tropical developing countries.

  18. Study of greenhouse gases reduction alternatives for the exploitation of non conventional oil sands in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Bouchonneau, Deborah [Institut Francais du Petrole (IFP), Paris (France)

    2008-07-01

    High energy prices and greenhouse gases reduction represent the main challenges the current worldwide energetic situation has to face. As a consequence, paradox strategies can be highlighted: oil prices are sufficiently high to exploit non conventional oil resources, like extra heavy oils and oil sands. But the production of these resources emits larger GHG than the conventional oil path and implies other major environmental issues (water management, risks of soil pollution, destruction of the boreal forest), incompatible with the rules validated by the protocol of Kyoto. At the light of the new greenhouse gases reduction regulation framework announced by the Canadian Federal government, this work focuses on the study of greenhouse gases reduction alternatives applied to the non conventional oil sands exploitation in Canada. (author)

  19. Differences between conventional and non-conventional MRI techniques in Parkinson’s disease

    Science.gov (United States)

    Baglieri, Annalisa; Marino, Maria Adele; Morabito, Rosa; Di Lorenzo, Giuseppe; Bramanti, Placido; Marino, Silvia

    2013-01-01

    Summary Magnetic resonance imaging (MRI) provides an in vivo assessment of cortical and subcortical regions affected in Parkinson’s disease (PD). This review summarizes the most important conventional and non-conventional MRI techniques applied in this field. Standard neuroimaging techniques have played a marginal role in the diagnosis and follow-up of PD, essentially being used only to discriminate atypical syndromes from PD, to exclude secondary causes such as vascular lesions, and to confirm the absence of specific imaging features found in atypical parkinsonisms. However, non-conventional MRI techniques, i.e. new neuroimaging approaches such as magnetic resonance spectroscopy, diffusion tensor imaging, and functional MRI, may allow the detection of structural, functional and metabolic changes useful not only for differential diagnosis, but also for early diagnosis and outcome and treatment monitoring in PD. In addition, we illustrate the advantages of high-field MRI over lower magnetic fields, highlighting the great potential of advanced neuroimaging techniques. PMID:24125556

  20. One-Dimensional Mass-Spring Chains Supporting Elastic Waves with Non-Conventional Topology

    Directory of Open Access Journals (Sweden)

    2016-04-01

    Full Text Available There are two classes of phononic structures that can support elastic waves with non-conventional topology, namely intrinsic and extrinsic systems. The non-conventional topology of elastic wave results from breaking time reversal symmetry (T-symmetry of wave propagation. In extrinsic systems, energy is injected into the phononic structure to break T-symmetry. In intrinsic systems symmetry is broken through the medium microstructure that may lead to internal resonances. Mass-spring composite structures are introduced as metaphors for more complex phononic crystals with non-conventional topology. The elastic wave equation of motion of an intrinsic phononic structure composed of two coupled one-dimensional (1D harmonic chains can be factored into a Dirac-like equation, leading to antisymmetric modes that have spinor character and therefore non-conventional topology in wave number space. The topology of the elastic waves can be further modified by subjecting phononic structures to externally-induced spatio-temporal modulation of their elastic properties. Such modulations can be actuated through photo-elastic effects, magneto-elastic effects, piezo-electric effects or external mechanical effects. We also uncover an analogy between a combined intrinsic-extrinsic systems composed of a simple one-dimensional harmonic chain coupled to a rigid substrate subjected to a spatio-temporal modulation of the side spring stiffness and the Dirac equation in the presence of an electromagnetic field. The modulation is shown to be able to tune the spinor part of the elastic wave function and therefore its topology. This analogy between classical mechanics and quantum phenomena offers new modalities for developing more complex functions of phononic crystals and acoustic metamaterials.

  1. EVALUATION OF PHYTOCHEMICAL CONSTITUENT IN CONVENTIONAL AND NON CONVENTIONAL SPECIES OF CURCUMA

    OpenAIRE

    Saxena Jyoti; Sahu Rajeshwari

    2012-01-01

    Plants and plant based medicaments are the basis of many of the modern pharmaceutical we use today for our various aliment. Plant show medicinal properties as it contain phytochemical constituent. Phytochemical constituent are non nutritive plant chemical that have disease preventive properties .This paper reports an investigation of phytochemical constituent present in the Methanolic crude rhizome extract of conventional and non conventional Curcuma species i.e Curcuma caecia , Curcuma amad...

  2. Fishbone activity in experimental advanced superconducting tokamak neutral beam injection plasma

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Liqing; Zhang, Jizong; Chen, Kaiyun, E-mail: Kychen@ipp.cas.cn, E-mail: lqhu@ipp.cas.cn; Hu, Liqun, E-mail: Kychen@ipp.cas.cn, E-mail: lqhu@ipp.cas.cn; Li, Erzhong; Lin, Shiyao; Shi, Tonghui; Duan, Yanmin [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zhu, Yubao [Department of Physics and Astronomy, University of California, Irvine, California 92697-4575 (United States)

    2015-12-15

    Repetitive fishbones near the trapped ion procession frequency were observed for the first time in the neutral beam injection high confinement plasmas in Experimental Advanced Superconducting Tokamak (EAST) tokamak, and diagnosed using a solid-state neutral particle analyzer based on a compact silicon photodiode together with an upgraded high spatial-temporal-resolution multi-arrays soft X-ray (SX) system. This 1/1 typical internal kink mode propagates in the ion-diamagnetism direction with a rotation speed faster than the bulk plasma in the plasma frame. From the SX measurements, this mode frequency is typical of chirping down and the energetic particle effect related to the twisting mode structure. This ion fishbone was found able to trigger a multiple core sawtooth crashes with edge-2/1 sideband modes, as well as to lead to a transition from fishbone to long lived saturated kink mode to fishbone. Furthermore, using SX tomography, a correlation between mode amplitude and mode frequency was found. Finally, a phenomenological prey–predator model was found to reproduce the fishbone nonlinear process well.

  3. Non-Conventional Yeast Strains Increase the Aroma Complexity of Bread.

    Science.gov (United States)

    Aslankoohi, Elham; Herrera-Malaver, Beatriz; Rezaei, Mohammad Naser; Steensels, Jan; Courtin, Christophe M; Verstrepen, Kevin J

    2016-01-01

    Saccharomyces cerevisiae is routinely used yeast in food fermentations because it combines several key traits, including fermentation efficiency and production of desirable flavors. However, the dominance of S. cerevisiae in industrial fermentations limits the diversity in the aroma profiles of the end products. Hence, there is a growing interest in non-conventional yeast strains that can help generate the diversity and complexity desired in today's diversified and consumer-driven markets. Here, we selected a set of non-conventional yeast strains to examine their potential for bread fermentation. Here, we tested ten non-conventional yeasts for bread fermentation, including two Saccharomyces species that are not currently used in bread making and 8 non-Saccharomyces strains. The results show that Torulaspora delbrueckii and Saccharomyces bayanus combine satisfactory dough fermentation with an interesting flavor profile. Sensory analysis and HS-SPME-GC-MS analysis confirmed that these strains produce aroma profiles that are very different from that produced by a commercial bakery strain. Moreover, bread produced with these yeasts was preferred by a majority of a trained sensory panel. These results demonstrate the potential of T. delbrueckii and S. bayanus as alternative yeasts for bread dough leavening, and provide a general experimental framework for the evaluation of more yeasts and bacteria.

  4. 4onse: four times open & non-conventional technology for sensing the environment

    Science.gov (United States)

    Cannata, Massimiliano; Ratnayake, Rangageewa; Antonovic, Milan; Strigaro, Daniele; Cardoso, Mirko; Hoffmann, Marcus

    2017-04-01

    The availability of complete, quality and dense monitoring hydro-meteorological data is essential to address a number of practical issues including, but not limited to, flood-water and urban drainage management, climate change impact assessment, early warning and risk management, now-casting and weather predictions. Thanks to the recent technological advances such as Internet Of Things, Big Data and Ubiquitous Internet, non-conventional monitoring systems based on open technologies and low cost sensors may represent a great opportunity either as a complement of authoritative monitoring network or as a vital source of information wherever existing monitoring networks are in decline or completely missing. Nevertheless, scientific literature on such a kind of open and non-conventional monitoring systems is still limited and often relates to prototype engineering and testing in rather limited case studies. For this reason the 4onse project aims at integrating existing open technologies in the field of Free & Open Source Software, Open Hardware, Open Data, and Open Standards and evaluate this kind of system in a real case (about 30 stations) for a medium period of 2 years to better scientifically understand strengths, criticalities and applicabilities in terms of data quality; system durability; management costs; performances; sustainability. The ultimate objective is to contribute in non-conventional monitoring systems adoption based on four open technologies.

  5. TREATMENT OF ACID MINE DRAINAGE USING FISHBONE APATITE IITM

    Energy Technology Data Exchange (ETDEWEB)

    Neal A. Yancey

    2006-10-01

    ABSTRACT. In 2000, a reactive barrier was installed on the East Fork of Ninemile Creek near Wallace, Idaho to treat acid mine discharge. The barrier was filled with fishbone derived Apatite IITM to remove the contaminants of concern (Zn, Pb, and Cd) and raise the pH of the acidic mine discharge. Metal removal has been achieved by a combination of chemical, biological, and physical precipitation. Flow for the water ranges from 5 to 35 gallons per minute. The water is successfully being treated, but the system experienced varying degrees of plugging. In 2002, gravel was mixed with the Apatite IITM to help control plugging. In 2003 the Idaho National Laboratory was ask to provide technical support to the Coeur d’Alene Basin Commission to help identify a remedy to the plugging issue. Air sparging was employed to treat the plugging issues. Plastic packing rings were added in the fall of 2005, which have increased the void space in the media and increased flows during the 10 months of operation since the improvements were made.

  6. It's a cod! Finding Nemo (impacted fishbone) in the emergency department.

    Science.gov (United States)

    McCabe, Aileen; Patton, Andrew; Salter, Nigel

    2017-06-15

    A 23-year-old woman presented to the emergency department (ED) with a sensation of a 'fish bone' stuck in her throat after eating cod. On physical examination, while she reported an uncomfortable sensation in her throat, no airway compromise was evident. Clinical examination, including ear, nose and throat (ENT) and oropharyngeal assessment, was unremarkable. A linear opacity consistent with a fishbone was visualised on a soft tissue lateral neck X-ray anterior to the vertebral body of C4-6. One attempt to visualise the fishbone on direct laryngoscopy failed in the ED. The fishbone was later removed the next day via direct visualisation with a flexible endoscope in the operating theatre by the ENT surgical team. The patient's recovery was uneventful. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  7. Non-Conventional Yeasts Whole Cells as Efficient Biocatalysts for the Production of Flavors and Fragrances

    Directory of Open Access Journals (Sweden)

    Luca Forti

    2015-06-01

    Full Text Available The rising consumer requests for natural flavors and fragrances have generated great interest in the aroma industry to seek new methods to obtain fragrance and flavor compounds naturally. An alternative and attractive route for these compounds is based on bio-transformations. In this review, the application of biocatalysis by Non Conventional Yeasts (NCYs whole cells for the production of flavor and fragrances is illustrated by a discussion of the production of different class of compounds, namely Aldehydes, Ketones and related compounds, Alcohols, Lactones, Terpenes and Terpenoids, Alkenes, and Phenols.

  8. Non-Conventional Yeasts Whole Cells as Efficient Biocatalysts for the Production of Flavors and Fragrances.

    Science.gov (United States)

    Forti, Luca; Di Mauro, Simone; Cramarossa, Maria Rita; Filippucci, Sara; Turchetti, Benedetta; Buzzini, Pietro

    2015-06-04

    The rising consumer requests for natural flavors and fragrances have generated great interest in the aroma industry to seek new methods to obtain fragrance and flavor compounds naturally. An alternative and attractive route for these compounds is based on bio-transformations. In this review, the application of biocatalysis by Non Conventional Yeasts (NCYs) whole cells for the production of flavor and fragrances is illustrated by a discussion of the production of different class of compounds, namely Aldehydes, Ketones and related compounds, Alcohols, Lactones, Terpenes and Terpenoids, Alkenes, and Phenols.

  9. Lateral Soft Tissue X-ray for Patients with Suspected Fishbone in Oropharynx, A thing in the past

    Directory of Open Access Journals (Sweden)

    Ali Sanei-Moghaddam

    2015-11-01

    Full Text Available Introduction: Fishbone is the most common foreign body found in the oropharynx. Conventionally patients with suspected fishbone in the throat would have mirror laryngoscopy followed by lateral soft tissue X-ray to look for the fishbone or observe impacts caused by the fishbone i.e. soft tissue swelling or air in upper esophagus. However, the most common site of fishbone impact is the suprahyoid area, which contains high soft tissue and bony density. This makes X-rays less reliable, especially because not all fish have radio-opaque bones. With the advent of fibreoptic nasendoscopy (FNE and improved access to CT scan, more reliable tools exist to treat patients with suspected fishbone in the oropharynx;   Materials and Methods:  A retrospective study, looking at 698 lateral soft tissue X-rays was performed. This study was conducted in Addenbrookes Hospital, Cambridge (UK between December 1st, 2004 and February 28th, 2011 using picture archiving and communication systems (PACS. All the radiology reports were reviewed and all the lateral soft tissue X-ray requests for foreign bodies other than fish bones were excluded.     Results: Of the 698 lateral soft tissue X-rays performed between December 1st, 2004 and February 28th, 2011, only 229 (32.8% were suspected to involve a fishbone in the throat. Amongst those requested for suspected fishbone injury, only 23 (10% cases were reported by the radiologist as positive for fishbone. Of the 23 patients with a positive finding on X-ray, 13 had negative FNE and were discharged from the hospital, while 5 had fishbone which were visualized using fibreoptic nasendoscope and removed. One patient had an appointment in order to be reviewed in the clinic, but did not show up. The notes for 4 patients were not found; however, there were no records on the hospital intranet suggesting that they had been to the operating room for an ENT procedure related to fishbone. Therefore, it is fair to assume that either

  10. Image Quality Modeling and Optimization for Non-Conventional Aperture Imaging Systems

    Science.gov (United States)

    Salvaggio, Philip S.

    The majority of image quality studies have been performed on systems with conventional aperture functions. These systems have straightforward aperture designs and well-understood behavior. Image quality for these systems can be predicted by the General Image Quality Equation (GIQE). However, in order to continue pushing the boundaries of imaging, more control over the point spread function of an imaging system may be necessary. This requires modifications in the pupil plane of a system, causing a departure from the realm of most image quality studies. Examples include sparse apertures, synthetic apertures, coded apertures and phase elements. This work will focus on sparse aperture telescopes and the image quality issues associated with them, however, the methods presented will be applicable to other non-conventional aperture systems. In this research, an approach for modeling the image quality of non-conventional aperture systems will be introduced. While the modeling approach is based in previous work, a novel validation study will be performed, which accounts for the effects of both broadband illumination and wavefront error. One of the key image quality challenges for sparse apertures is post-processing ringing artifacts. These artifacts have been observed in modeled data, but a validation study will be performed to observe them in measured data and to compare them to model predictions. Once validated, the modeling approach will be used to perform a small set of design studies for sparse aperture systems, including spectral bandpass selection and aperture layout optimization.

  11. Electronic structures of topological insulator Bi2Te3 surfaces with non-conventional terminations

    Science.gov (United States)

    Zhu, Xie-Gang; Zhang, Yun; Feng, Wei; Yuan, Bing-Kai; Liu, Qin; Qiu, Rui-Zhi; Xie, Dong-Hua; Tan, Shi-Yong; Duan, Yu; Fang, Yun; Zhang, Wen; Lai, Xin-Chun

    2016-09-01

    Topological insulators (TIs) are theoretically believed to possess robust surface states (SSs) for any surface terminations. In reality, for TIs with non-conventional terminations, the directly experimental demonstration of this argument is somehow hindered, due to the difficulties in sample preparation and lack of efficient electronic structure characterization method. Here, by using the state-of-the-art molecular beam epitaxy, we manage to prepare TI Bi2Te3 thin film with non-conventional fractional quintuple layer (FQL) termination. Scanning tunneling microscopy reveals that the as-grown Bi2Te3 thin film may not necessarily terminate at the van der Waals gap between two adjacent quintuple layers. The electronic structures of the FQL termination are studied in combination with quasi-particle interference pattern by scanning tunneling spectroscopy and SS calculations by tight binding method. Our results suggest that the topological nature of SSs be preserved on various terminations. Possible ways of achieving exotic topological SSs are also discussed.

  12. Comparison of conventional and non conventional methods of extraction of heartwood of Pterocarpus marsupium Roxb.

    Science.gov (United States)

    Devgun, Manish; Nanda, Arun; Ansari, Shahid H

    2012-01-01

    The renewed interest in plant-derived drugs has led to an increased need for efficient extraction methods. The present investigation was an attempt to evaluate and compare the conventional methods of extraction with non conventional methods of extraction, such as ultrasonic-assisted extraction (UAE) and microwave-assisted extraction (MAE) methods. Pterocarpus marsupium Roxb. has been reported to contain bioactive phytochemicals, e.g., pterostilbene (3',5'-dimethoxy-4-stilbenol). The results showed that among the conventional extraction methods, percolation gave the highest yield. The non conventional methods were optimized. The extraction yield was the highest in case of MAE. The phytochemical screening of the extracts indicated similar groups of compounds in all the extracts. The thin layer chromatography showed the presence of pterostilbene in the extracts obtained by using percolation, MAE and UAE. In these extracts the quantification of pterostilbene was conducted by high performance liquid chromatography and the method was validated. The MAE method extracted significantly higher amount of pterostilbene.

  13. Data quality control methodologies for large, non-conventional DC resistivity datasets

    Science.gov (United States)

    Mitchell, Michael A.; Oldenburg, Douglas W.

    2016-12-01

    With developments in instrumentation and computational resources, the collection of large, non-conventional DC resistivity datasets has become commonplace. While the increased data content of these large datasets can significantly improve the resolution of inverse models, these datasets also present challenges for standard data quality control (QC) methodologies. Standard QC methodologies for DC resistivity datasets typically rely on our ability to decompose the dataset into 2D lines and/or reciprocal measurements. Non-conventional electrode geometries and the cost of collecting a large number of reciprocal measurements can severely limit the applicability of standard DC resistivity QC methodologies. To address these limitations, we developed a more generalized data QC methodology which utilizes statistical analysis and classification tools. The merit of this methodology is illustrated using a field dataset collected in an underground potash mine and several synthetic examples. Results from these applications show that the methodology has the ability to identify and characterize highly noise-contaminated data from a number of different sources. The flexibility of the 4-stage methodology allows it be tailored to accommodate data from any type of DC resistivity survey and the use of statistical analysis and classification tools decreases the subjectivity of the process. Although this study focuses on the applicability of this methodology for DC resistivity data, it is potentially applicable to a variety of geophysical surveys.

  14. Modulation of the toxicity of photons by non-conventional drugs

    Energy Technology Data Exchange (ETDEWEB)

    Bohm, L.; Theron, T.; Serafin, A.; Verheye, F. [Department of Radiation Oncology, Faculty of Medicine, University of Stellenbosch, (South Africa)

    1997-03-01

    The 3 drugs under investigation Pentoxifylline, Ouabain and Thalidomide are non-conventional in the sense that they have a low toxicity and do not damage DNA. Pentoxifylline reduces blood viscosity ad enhances peripheral blood flow. When combined with irradiation in a mouse rhabdomyosarcoma model we found markedly enhanced tumour growth delay and in cultured cells dose modifying factors for SF2 and alpha in the region of 1.2-1.7 (Strahlentherapie 1995;170:595-01). The drug also alters cell regulation by inhibiting the radiation induced G2/M block and suppressing control of DNA synthesis (Theron and Boehm, unpubl.). When Thalidomide was added in the absence of irradiation to the myelo-blastic cell line K-562 we found characteristic changes of cell morphology and cell surface markers suggesting differentiation and expression of a megacaryocytic lineage (Leukemia Research 1991;15:129-136). A summary of the current state of research is given. (authors)

  15. Nutritional value of some non-conventional plant foods of India.

    Science.gov (United States)

    Duhan, A; Chauhan, B M; Punia, D

    1992-07-01

    Thirteen non-conventional foods including fruits, leaves and grains consumed in various parts of the Indian subcontinent were analysed for their nutritional value. Khejri beans (Prsopsis cineria), Pinju (Capparis decidua) and Kachri (Cucumis species) contained considerable amounts of protein (15-18%). Kachri was rich in fat (13%). Bhakri (Tribulus terristris), Gullar (Ficus glomerata) and Peehl (Salvadora oleoides) were found to be rich sources of calcium; Gullar contained about 15 times the amount of calcium present in wheat. Phosphorus content of Santhi (Boernavia diffusa), Khejri beans, Bhakri, Pinju and Lehsora (Cordia dichotoma) were noticeable. Zinc was present in high amounts in Peepalbanti (Ficus religiosa) and Gullar; as was iron in Santhi and Bhakri and manganese in Santhi. Besides iron, zinc and calcium, Pinju contained appreciable amounts of beta-carotene and vitamin C. However, Santhi contained high amounts of oxalic acid.

  16. Non-Conventional Applications of Computerized Tomography: Analysis of Solid Dosage Forms Produced by Pharmaceutical Industry

    Science.gov (United States)

    de Oliveira, José Martins; Germano Martins, Antonio César

    2010-05-01

    X-ray computed tomography (CT) refers to the cross-sectional imaging of an object measuring the transmitted radiation at different directions. In this work, we describe a non-conventional application of computerized tomography: visualization and improvements in the understanding of some internal structural features of solid dosage forms. A micro-CT X-ray scanner, with a minimum resolution of 30 μm was used to characterize some pharmaceutical tablets, granules, controlled-release osmotic tablet and liquid-filled soft-gelatin capsules. The analysis presented in this work are essentially qualitative, but quantitative parameters, such as porosity, density distribution, tablets dimensions, etc. could also be obtained using the related CT techniques.

  17. Synthetic biology and molecular genetics in non-conventional yeasts: Current tools and future advances.

    Science.gov (United States)

    Wagner, James M; Alper, Hal S

    2016-04-01

    Coupling the tools of synthetic biology with traditional molecular genetic techniques can enable the rapid prototyping and optimization of yeast strains. While the era of yeast synthetic biology began in the well-characterized model organism Saccharomyces cerevisiae, it is swiftly expanding to include non-conventional yeast production systems such as Hansenula polymorpha, Kluyveromyces lactis, Pichia pastoris, and Yarrowia lipolytica. These yeasts already have roles in the manufacture of vaccines, therapeutic proteins, food additives, and biorenewable chemicals, but recent synthetic biology advances have the potential to greatly expand and diversify their impact on biotechnology. In this review, we summarize the development of synthetic biological tools (including promoters and terminators) and enabling molecular genetics approaches that have been applied in these four promising alternative biomanufacturing platforms. An emphasis is placed on synthetic parts and genome editing tools. Finally, we discuss examples of synthetic tools developed in other organisms that can be adapted or optimized for these hosts in the near future.

  18. Non-conventional possibilities of protection of apple and pear against fire blight (Erwinia amylovora

    Directory of Open Access Journals (Sweden)

    Piotr Sobiczewski

    2013-12-01

    Full Text Available Standard program of plant protection against fire blight consists of use of management practices and chemical control method. Recently a new, non-conventional possibilities based on application of biocontrol agents (two biopreparations have been already introduced into practice: Bliteban A506 (Pseudomonas fluorescens and BlossomBless (Pantoea agglomerans, plant extracts active against Erwinia amylovora (AkseBio containing extracts from Thymbra spicata and Biomit Plussz with extracts from various plant species and microelements and resistance inducers (Regalis, Bion and plant extracts are of great interest. Also plant transformation with resistance genes such as: hrpN (harpin, dpo (EPS depolymerase and lytic protein genes (attacin E, cecropin SB-37, T4 lysozyme is a promising perspective.

  19. Opportunities for utilization of non-conventional energy sources for biomass pretreatment.

    Science.gov (United States)

    Singh, Rawel; Krishna, Bhavya B; Kumar, Jitendra; Bhaskar, Thallada

    2016-01-01

    The increasing concerns over the depletion of fossil resources and its associated geo-political issues have driven the entire world to move toward sustainable forms of energy. Pretreatment is the first step in any biochemical conversion process for the production of valuable fuels/chemicals from lignocellulosic biomass to eliminate the lignin and produce fermentable sugars by hydrolysis. Conventional techniques have several limitations which can be addressed by using them in tandem with non-conventional methods for biomass pretreatment. Electron beam and γ (gamma)-irradiation, microwave and ultrasound energies have certain advantages over conventional source of energy and there is an opportunity that these energies can be exploited for biomass pretreatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Optical characterization of heavy metal non-conventional binary PbO-ZnO glasses

    Science.gov (United States)

    Marzouk, M. A.; Fayad, A. M.

    2014-07-01

    Non-conventional heavy metal oxide glasses of the system (100- x) PbO- xZnO in the composition range 5-40 mol% of ZnO have been prepared by melt-quenching technique. X-ray diffraction, UV-visible, and Fourier transform infrared (FTIR) absorption spectroscopy techniques were applied for the characterization of prepared glasses. From the absorption edge studies, the values of the optical band gap E opt and Urbach energy (∆ E) have been evaluated. From the experimental results, values of the optical energy gap are calculated and found to be dependent on the glass composition. FTIR spectra of the glasses reveal vibrational modes characteristic to combined presence of tetrahedral PbO4 and ZnO4 units in their specific different wavenumbers.

  1. Ratcheting Behavior of a Non-conventional Stainless Steel and Associated Microstructural Variations

    Science.gov (United States)

    Sahu, Lopamudra; Mishra, Awanish Kumar; Dutta, Krishna

    2014-11-01

    Ratcheting fatigue behavior of a non-conventional stainless steel X12CrMnNiN17-7-5 has been investigated with varying combinations of mean stress (σm) and stress amplitude (σa) at room temperature using a servo-hydraulic universal testing machine. X-ray diffraction profile analysis has been carried out for assessing possible martensitic phase transformation in the steel subjected to ratcheting deformation. The results indicate that ratcheting strain as well as volume fraction of martensite increases with increasing σm and/or σa; the phenomenon of strain accumulation is considered to be governed by the associated mechanics of cyclic loading, increased plastic damage as well as martensitic transformation. A correlation between strain produced by ratcheting deformation and martensitic transformation has been established.

  2. Synthetic Biology and Metabolic Engineering Approaches and Its Impact on Non-Conventional Yeast and Biofuel Production

    Directory of Open Access Journals (Sweden)

    Raveendran Sindhu

    2017-04-01

    Full Text Available The increasing fossil fuel scarcity has led to an urgent need to develop alternative fuels. Currently microorganisms have been extensively used for the production of first-generation biofuels from lignocellulosic biomass. Yeast is the efficient producer of bioethanol among all existing biofuels option. Tools of synthetic biology have revolutionized the field of microbial cell factories especially in the case of ethanol and fatty acid production. Most of the synthetic biology tools have been developed for the industrial workhorse Saccharomyces cerevisiae. The non-conventional yeast systems have several beneficial traits like ethanol tolerance, thermotolerance, inhibitor tolerance, genetic diversity, etc., and synthetic biology have the power to expand these traits. Currently, synthetic biology is slowly widening to the non-conventional yeasts like Hansenula polymorpha, Kluyveromyces lactis, Pichia pastoris, and Yarrowia lipolytica. Herein, we review the basic synthetic biology tools that can apply to non-conventional yeasts. Furthermore, we discuss the recent advances employed to develop efficient biofuel-producing non-conventional yeast strains by metabolic engineering and synthetic biology with recent examples. Looking forward, future synthetic engineering tools’ development and application should focus on unexplored non-conventional yeast species.

  3. Effects of degumming on biodiesel properties of some non-conventional seedoils

    Directory of Open Access Journals (Sweden)

    Abolanle Saheed Adekunle

    2016-11-01

    Full Text Available This study examined the effect of degumming process on physicochemical and biodiesel properties of six non-conventional oils in Nigeria extracted from the seeds and flesh of Terminalia catappa (seed, Irvingia gabonesis (seed, Glycine max (seed, Persea americana(flesh, Tithonia diversifolia (seed, and Dacryodes edulis(flesh. The fruits and seeds were air-dried to constant weight and pulverized. Oil was extracted from the milled sample using Soxhlet extraction method. The oils were degummed using 300 μg/mL of NaCl solution to obtain the refined (degummed oil. Physicochemical properties of both degummed and crude oils were carried out using the AOAC (1990 methods. The fuel properties of the biodiesel obtained were carried out using ASTM methods. Results showed that degumming process lead to high biodiesel yield and reduced the acid value and iodine value compared with the crude oils. The study therefore concluded that degummed oils were a better substitute for biodiesel fuels production.

  4. The importance of sourcing enzymes from non-conventional fungi for metabolic engineering and biomass breakdown.

    Science.gov (United States)

    Seppälä, Susanna; Wilken, St Elmo; Knop, Doriv; Solomon, Kevin V; O'Malley, Michelle A

    2017-09-21

    A wealth of fungal enzymes has been identified from nature, which continue to drive strain engineering and bioprocessing for a range of industries. However, while a number of clades have been investigated, the vast majority of the fungal kingdom remains unexplored for industrial applications. Here, we discuss selected classes of fungal enzymes that are currently in biotechnological use, and explore more basal, non-conventional fungi and their underexploited biomass-degrading mechanisms as promising agents in the transition towards a bio-based society. Of special interest are anaerobic fungi like the Neocallimastigomycota, which were recently found to harbor the largest diversity of biomass-degrading enzymes among the fungal kingdom. Enzymes sourced from these basal fungi have been used to metabolically engineer substrate utilization in yeast, and may offer new paths to lignin breakdown and tunneled biocatalysis. We also contrast classic enzymology approaches with emerging 'omics'-based tools to decipher function within novel fungal isolates and identify new promising enzymes. Recent developments in genome editing are expected to accelerate discovery and metabolic engineering within these systems, yet are still limited by a lack of high-resolution genomes, gene regulatory regions, and even appropriate culture conditions. Finally, we present new opportunities to harness the biomass-degrading potential of undercharacterized fungi via heterologous expression and engineered microbial consortia. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  5. Application of anhydrobiosis and dehydration of yeasts for non-conventional biotechnological goals.

    Science.gov (United States)

    Rapoport, Alexander; Turchetti, Benedetta; Buzzini, Pietro

    2016-06-01

    Dehydration of yeast cells causes them to enter a state of anhydrobiosis in which their metabolism is temporarily and reversibly suspended. This unique state among organisms is currently used in the production of active dry yeasts, mainly used in baking and winemaking. In recent decades non-conventional applications of yeast dehydration have been proposed for various modern biotechnologies. This mini-review briefly summarises current information on the application of dry yeasts in traditional and innovative fields. It has been shown that dry yeast preparations can be used for the efficient protection, purification and bioremediation of the environment from heavy metals. The high sorption activity of dehydrated yeasts can be used as an interesting tool in winemaking due to their effects on quality and taste. Dry yeasts are also used in agricultural animal feed. Another interesting application of yeast dehydration is as an additional stage in new methods for the stable immobilisation of microorganisms, especially in cases when biotechnologically important strains have no affinity with the carrier. Such immobilisation methods also provide a new approach for the successful conservation of yeast strains that are very sensitive to dehydration. In addition, the application of dehydration procedures opens up new possibilities for the use of yeast as a model system. Separate sections of this review also discuss possible uses of dry yeasts in biocontrol, bioprotection and biotransformations, in analytical methods as well as in some other areas.

  6. Synthetic biology for manufacturing chemicals: constraints drive the use of non-conventional microbial platforms.

    Science.gov (United States)

    Czajka, Jeffrey; Wang, Qinhong; Wang, Yechun; Tang, Yinjie J

    2017-09-07

    Genetically modified microbes have had much industrial success producing protein-based products (such as antibodies and enzymes). However, engineering microbial workhorses for biomanufacturing of commodity compounds remains challenging. First, microbes cannot afford burdens with both overexpression of multiple enzymes and metabolite drainage for product synthesis. Second, synthetic circuits and introduced heterologous pathways are not yet as "robust and reliable" as native pathways due to hosts' innate regulations, especially under suboptimal fermentation conditions. Third, engineered enzymes may lack channeling capabilities for cascade-like transport of metabolites to overcome diffusion barriers or to avoid intermediate toxicity in the cytoplasmic environment. Fourth, moving engineered hosts from laboratory to industry is unreliable because genetic mutations and non-genetic cell-to-cell variations impair the large-scale fermentation outcomes. Therefore, synthetic biology strains often have unsatisfactory industrial performance (titer/yield/productivity). To overcome these problems, many different species are being explored for their metabolic strengths that can be leveraged to synthesize specific compounds. Here, we provide examples of non-conventional and genetically amenable species for industrial manufacturing, including the following: Corynebacterium glutamicum for its TCA cycle-derived biosynthesis, Yarrowia lipolytica for its biosynthesis of fatty acids and carotenoids, cyanobacteria for photosynthetic production from its sugar phosphate pathways, and Rhodococcus for its ability to biotransform recalcitrant feedstock. Finally, we discuss emerging technologies (e.g., genome-to-phenome mapping, single cell methods, and knowledge engineering) that may facilitate the development of novel cell factories.

  7. Oil shale, shale oil, shale gas and non-conventional hydrocarbons

    Directory of Open Access Journals (Sweden)

    Clerici A.

    2015-01-01

    Full Text Available In recent years there has been a world “revolution” in the field of unconventional hydrocarbon reserves, which goes by the name of “shale gas”, gas contained inside clay sediments micropores. Shale gas finds particular development in the United States, which are now independent of imports and see a price reduction to less than one third of that in Europe. With the high oil prices, in addition to the non-conventional gas also “oil shales” (fine-grained sedimentary rocks that contain a large amount of organic material to be used both to be directly burned or to extract liquid fuels which go under the name of shale oil, extra heavy oils and bitumen are becoming an industrial reality. Both unconventional gas and oil reserves far exceed in the world the conventional oil and gas reserves, subverting the theory of fossil fuels scarcity. Values and location of these new fossil reserves in different countries and their production by comparison with conventional resources are presented. In view of the clear advantages of unconventional fossil resources, the potential environmental risks associated with their extraction and processing are also highlighted.

  8. Scaling-up of complex whole-cell bioconversions in conventional and non-conventional media.

    Science.gov (United States)

    Marques, Marco P C; de Carvalho, Carla C C R; Cabral, Joaquim M S; Fernandes, Pedro

    2010-07-01

    The use of whole cells is becoming a more common approach in pharmaceutical and agrochemical industries in order to obtain pure compounds with fewer production steps, higher yields, and cleaner processes, as compared to those achieved with traditional strategies. Whole cells are often used as enzymes pools, in particular when multi-step reactions and/or co-factor regeneration are envisaged. Nonetheless, published information on the scale-up of such systems both in aqueous and in two-phase aqueous-organic systems is relatively scarce. The present work aims to evaluate suitable scale-up criteria in conventional and non-conventional medium for a whole-cell bioconversion that uses resting cells of Mycobacterium sp. NRRL B-3805 to cleave the side chain of beta-sitosterol, a poorly water-soluble substrate. The experiments were performed in 24-well microtiter plates and in 250 mL shaken flasks as orbital stirred systems, and in 300 mL stirred tanks as mechanically stirred systems. Results show that productivity yields were similar in all scales tested, when maintaining oxygen mass transfer coefficients constant in aqueous systems, or when maintaining constant volumetric power consumption in aqueous-organic two-phase systems.

  9. Mechanism of the Reduced Thermal Conductivity of Fishbone-Type Si Phononic Crystal Nanostructures

    Science.gov (United States)

    Nomura, M.; Maire, J.

    2015-06-01

    The mechanism of the reduced thermal conductivity of fishbone-type phononic crystal (PnC) nanostructures, in which ballistic phonon transport is dominant, was investigated with consideration of both the wave and particle nature of phonons. Phononic band diagrams were calculated for an Si nanowire and a fishbone-type PnC structure with a period of 100 nm, and a clear reduction of the group velocity of phonons, because of a zone-folding effect, was shown. Air-suspended Si nanowires and fishbone-type PnC structures were fabricated by electron beam (EB) lithography, and their thermal conductivities were measured by use of the originally developed micro time-domain thermoreflectance method. The PnC structure had a much lower thermal conductivity. We measured the thermal conductivity of a variety of PnC structures with different fin widths to investigate the mechanism of the reduced thermal conductivity observed. The result indicates that the increase of the phonon traveling distance. as a result of the fins, also results in reduced thermal conductivity.

  10. Metabolic engineering of the non-conventional yeast Pichia ciferrii for production of rare sphingoid bases.

    Science.gov (United States)

    Börgel, Daniel; van den Berg, Marco; Hüller, Thomas; Andrea, Heiko; Liebisch, Gerhard; Boles, Eckhard; Schorsch, Christoph; van der Pol, Ruud; Arink, Anne; Boogers, Ilco; van der Hoeven, Rob; Korevaar, Kees; Farwick, Mike; Köhler, Tim; Schaffer, Steffen

    2012-07-01

    The study describes the identification of sphingolipid biosynthesis genes in the non-conventional yeast Pichia ciferrii, the development of tools for its genetic modification as well as their application for metabolic engineering of P. ciferrii with the goal to generate strains capable of producing the rare sphingoid bases sphinganine and sphingosine. Several canonical genes encoding ceramide synthase (encoded by PcLAG1 and PcLAF1), alkaline ceramidase (PcYXC1) and sphingolipid C-4-hydroxylase(PcSYR2), as well as structural genes for dihydroceramide Δ(4)-desaturase (PcDES1) and sphingolipid Δ(8)-desaturase (PcSLD1) were identified, indicating that P. ciferrii would be capable of synthesizing desaturated sphingoid bases, a property not ubiquitously found in yeasts. In order to convert the phytosphingosine-producing P. ciferrii wildtype into a strain capable of producing predominantly sphinganine, Syringomycin E-resistant mutants were isolated. A stable mutant almost exclusively producing high levels of acetylated sphinganine was obtained and used as the base strain for further metabolic engineering. A metabolic pathway required for the three-step conversion of sphinganine to sphingosine was implemented in the sphinganine producing P. ciferrii strain and subsequently enhanced by screening for the appropriate heterologous enzymes, improvement of gene expression and codon optimization. These combined efforts led to a strain capable of producing 240mgL(-1) triacetyl sphingosine in shake flask, with tri- and diacetyl sphinganine being the main by-products. Lab-scale fermentation of this strain resulted in production of up to 890mgkg(-1) triacetyl sphingosine. A third by-product was unequivocally identified as triacetyl sphingadienine. It could be shown that inactivation of the SLD1 gene in P. ciferrii efficiently suppresses triacetyl sphingadienine formation. Further improvement of the described P. ciferrii strains will enable a biotechnological route to produce

  11. Non-conventional Yeast Species for Lowering Ethanol Content of Wines

    Science.gov (United States)

    Ciani, Maurizio; Morales, Pilar; Comitini, Francesca; Tronchoni, Jordi; Canonico, Laura; Curiel, José A.; Oro, Lucia; Rodrigues, Alda J.; Gonzalez, Ramon

    2016-01-01

    Rising sugar content in grape must, and the concomitant increase in alcohol levels in wine, are some of the main challenges affecting the winemaking industry nowadays. Among the several alternative solutions currently under study, the use of non-conventional yeasts during fermentation holds good promise for contributing to relieve this problem. Non-Saccharomyces wine yeast species comprise a high number or species, so encompassing a wider physiological diversity than Saccharomyces cerevisiae. Indeed, the current oenological interest of these microorganisms was initially triggered by their potential positive contribution to the sensorial complexity of quality wines, through the production of aroma and other sensory-active compounds. This diversity also involves ethanol yield on sugar, one of the most invariant metabolic traits of S. cerevisiae. This review gathers recent research on non-Saccharomyces yeasts, aiming to produce wines with lower alcohol content than those from pure Saccharomyces starters. Critical aspects discussed include the selection of suitable yeast strains (considering there is a noticeable intra-species diversity for ethanol yield, as shown for other fermentation traits), identification of key environmental parameters influencing ethanol yields (including the use of controlled oxygenation conditions), and managing mixed fermentations, by either the sequential or simultaneous inoculation of S. cerevisiae and non-Saccharomyces starter cultures. The feasibility, at the industrial level, of using non-Saccharomyces yeasts for reducing alcohol levels in wine will require an improved understanding of the metabolism of these alternative yeast species, as well as of the interactions between different yeast starters during the fermentation of grape must. PMID:27199967

  12. The Seductive Power of an Innovation: Enrolling Non-Conventional Actors in a Drip Irrigation Community in Morocco

    Science.gov (United States)

    Benouniche, Maya; Errahj, Mostafa; Kuper, Marcel

    2016-01-01

    Purpose: The aim of this study was to analyze the motivations of non-conventional innovation actors to engage in innovation processes, how their involvement changed the technology and their own social-professional status, and to analyze their role in the diffusion of the innovation. Design/methodology/approach: We studied the innovation process of…

  13. Soluble model of Bose-atoms with two level internal structure: non-conventional Bose-Einstein condensation

    Directory of Open Access Journals (Sweden)

    M. Corgini

    2010-01-01

    Full Text Available For a Bose atom system whose energy operator is diagonal in the so-called number operators and its ground state has an internal two-level structure with negative energies, exact expressions for the limit free canonical energy and pressure are obtained. The existence of non-conventional Bose-Einstein condensation has been also proved.

  14. Participation of non-conventional energy resources in power system frequency control

    Science.gov (United States)

    Aghazadeh Tabrizi, Mehriar

    Frequency control is one of the key issues in designing, planning and reliably operating a power system and is becoming more challenging as new complexities and uncertainties are introduced into the modern power systems. Traditionally, power system frequency has been controlled using conventional generation units' capabilities namely inertial, primary and secondary frequency responses. Limited fossil-based fuel resources, ever-increasing energy consumption and rising public awareness for environmental protection have created growing interest in use of non-conventional energy resources such as Wind Generation Resources (WGRs) and Solar Generation Resources (SGRs) which have unfavorable characteristics in comparison with conventional generation units such as lack of frequency response. The more conventional generation units are replaced by these resources, the more challenges power system operators will face in terms of power system frequency control. These challenges are further compounded due to less system inertia during off-peak hours or within small power systems. This dissertation mainly focuses on participation of SGRs and Interior Permanent Magnet Synchronous Generator (IPMSG) based WGRs in power system frequency control. Detailed information regarding dynamic modeling of power system including conventional generation units, SGRs and IPMSG based WGRs is provided. The frequency response of conventional generation units is compared with that of SGRs and IPMSG based WGRs. The control systems associated with IPMSG based WGR and SGR are modified in order to improve their frequency response capabilities. The effectiveness of the proposed control strategies is evaluated and confirmed via MATLAB based time-domain simulations for different scenarios. Moreover, application of Battery Energy Storage Systems (BESSs) in power system frequency regulation is discussed. The detailed dynamic model of BESSs is utilized to develop a simplified model suitable for Automatic

  15. SYNTHESIS AND MESOMORPHIC PROPERTIES OF FISHBONE-LIKE LIQUID CRYSTALLINE POLYSILSESQUIOXANES Ⅰ. FISHBONE-LIKE, β-DIKETONE-BASED LIQUID CRYSTALLINE POLYSILSESQUIOXANES AND THEIR COPPER COMPLEXES

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rongben; XIE Zushou; WAN Youzhi; JIN Sunzhi; HOU Jianan

    1993-01-01

    Two kinds of fishbone-like, β-diketone-based liquid crystalline polysilsesquioxanes (FBDKLCP'S),homopolymeric (H-FBDKLCP) and copolymeric (C-FBDKLCP) have been first synthesized via the hydrosilylation reaction of a vinyl-terminated β-diketone with the homopolymeric ladderlike polyhydrosilsesquioxane (LPHSQ) and random copolymethylhydrosilsesquioxane (LRPMHSQ) respectively. These new kinds of FBDKLCP with Mw of 104 is thermotroic liquid crystalline polymer and its clearing temperatures Ti's and mesophase range △T's are much higher than those of the corresponding comb-like β-diketone liquid crystalline polysiloxane (DKLCP) by about 200 ℃ . Similar results have been observed with the comparison of the two different structure Cu-coordinating compounds The significant increases in Td,l's and △T's of the FBDKLCP and Cu-FBDKLCP are mainly attributed to the great rigidity of the ladderlike polysilsesquioxane backbone.

  16. Spin-dependent conductance of a typical fishbone-like nanostructure

    Directory of Open Access Journals (Sweden)

    M Mardaani

    2012-09-01

    Full Text Available In this study, we investigated the spin dependent electronic transport of a fishbone-like nanostructure including two magnetic atoms at its ends. The electronic conductance of this nanostructure for three different orientations of atomic magnetic moments was numerically studied when the structure was sandwiched between two nonmagnetic leads. By using Green’s function technique at the tight-binding model, we calculated the spin dependent electronic transmission coefficient. The calculated results revealed that the conductance depends on the incident electron energy as well as the magnitude and orientation of atomic magnetic moments in the nanostructure.

  17. Non-Conventional Tools to Preserve and Prolong the Quality of Minimally-Processed Fruits and Vegetables

    Directory of Open Access Journals (Sweden)

    Maria Rosaria Corbo

    2015-11-01

    Full Text Available The main topic of this paper is a focus on some non-conventional tools to preserve the microbiological and physico-chemical quality of fresh-cut fruits and vegetables. The quality of fresh-cut foods is the result of a complex equilibrium involving surface microbiota, storage temperature, gas in the headspace and the use of antimicrobials. This paper proposes a short overview of some non-conventional approaches able to preserve the quality of this kind of product, with a special focus on some new ways, as follows: (1 use of edible or antimicrobial-containing coatings (e.g., chitosan-based coatings on fruits or vegetables; (2 alternative modified atmospheres (e.g., high O2-modified atmosphere packaging (MAP or the use of essential oils in the headspace; (3 conditioning solutions with antimicrobials or natural compounds for fruit salad; and (4 biopreservation and use of a probiotic coating.

  18. Incorporation of lactations with non-conventional drying-off causes in genetic evaluation of Gyr dairy cattle

    Directory of Open Access Journals (Sweden)

    João Cruz Reis Filho

    2012-09-01

    Full Text Available Test-day records of milk yields from the first three lactations were used to verify consequences of incorporation of lactation with non-conventional drying-off causes in genetic evaluation of Gyr dairy cattle. The first file (File1 was composed of test-day records of lactations with conventional drying-off causes. In the second file (File2, the test-day records of lactations with non-conventional drying-off causes were included, such as drying-off by death or separation of the calf, disease, death or sale of cow, and removal of cow from milking control. Data were analyzed by mixed models, using an autoregressive process to adjust the random effects of long-term and short-term environment. The inclusion of test-day records from lactations with non-conventional drying-off causes increased the number of controls by 12% and the number of cows by 18%, and it generated an increase in the estimates of variance components. These results impacted estimates of heritability, calculated at 0.32, 0.28 and 0.26 for the first, second and third lactations in File1, respectively, while in File2 they were 0.34, 0.30 and 0.28 to the same lactation order. The estimated accuracy of predicted breeding values in File2 were higher in relation to File1, but the Pearson and Spearman correlations between predicted breeding values of animals in the two files were high. Lactations with non-conventional drying-off causes can be incorporated to the routines of genetic evaluation of Gyr dairy cattle, because they provide higher estimates of heritability and accuracy of breeding values, which could raise expectations of genetic gains with selection.

  19. CQI in anemia management: using the fishbone approach to improve outcomes. Case study of the anemic patient.

    Science.gov (United States)

    Breiterman-White, R

    1999-04-01

    Anemia management outcomes can be improved through a concentrated effort by nephrology nurses and other members of the nephrology team. This article focuses on the use of a Fishbone CQI diagram that can help clinicians identify and manage specific etiologies that effect erythropoiesis.

  20. A Survey of Non-conventional Techniques for Low-voltage Low-power Analog Circuit Design

    Directory of Open Access Journals (Sweden)

    F. Khateb

    2013-06-01

    Full Text Available Designing integrated circuits able to work under low-voltage (LV low-power (LP condition is currently undergoing a very considerable boom. Reducing voltage supply and power consumption of integrated circuits is crucial factor since in general it ensures the device reliability, prevents overheating of the circuits and in particular prolongs the operation period for battery powered devices. Recently, non-conventional techniques i.e. bulk-driven (BD, floating-gate (FG and quasi-floating-gate (QFG techniques have been proposed as powerful ways to reduce the design complexity and push the voltage supply towards threshold voltage of the MOS transistors (MOST. Therefore, this paper presents the operation principle, the advantages and disadvantages of each of these techniques, enabling circuit designers to choose the proper design technique based on application requirements. As an example of application three operational transconductance amplifiers (OTA base on these non-conventional techniques are presented, the voltage supply is only ±0.4 V and the power consumption is 23.5 µW. PSpice simulation results using the 0.18 µm CMOS technology from TSMC are included to verify the design functionality and correspondence with theory.

  1. Performance of non-conventional yeasts in co-culture with brewers' yeast for steering ethanol and aroma production.

    Science.gov (United States)

    van Rijswijck, Irma M H; Wolkers-Rooijackers, Judith C M; Abee, Tjakko; Smid, Eddy J

    2017-08-18

    Increasing interest in new beer types has stimulated the search for approaches to extend the metabolic variation of brewers' yeast. Therefore, we tested two approaches using non-conventional yeast to create a beer with lower ethanol content and a complex aroma bouquet. First, the mono-culture performance was monitored of 49 wild yeast isolates of Saccharomyces cerevisiae (16 strains), Cyberlindnera fabianii (9 strains) and Pichia kudriavzevii (24 strains). Interestingly, both C. fabianii and P. kudriavzevii isolates produced relatively more esters compared with S. cerevisiae isolates, despite their limited fermentation capacity. Next, one representative strain of each species (Sc131, Cf65 and Pk129) was applied as co-culture with brewers' yeast (ratio 1:1). Co-cultures with Cf65 and Pk129 resulted in a beer with lower alcohol content (3.5, 3.8 compared with 4.2% v/v) and relatively more esters. At higher inoculum ratios of Cf65 over brewers' yeast, growth inhibition of brewers' yeast was observed, most likely caused by competition for oxygen between brewers' yeast and Cf65 resulting in a reduced level of ethanol and altered aroma profiles. With this study, we demonstrate the feasibility of using non-conventional yeast species in co-cultivation with traditional brewers' yeast to tailor aroma profiles as well as the final ethanol content of beer. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  2. Probing Formability Improvement of Ultra-thin Ferritic Stainless Steel Bipolar Plate of PEMFC in Non-conventional Forming Process

    Science.gov (United States)

    Bong, Hyuk Jong; Barlat, Frédéric; Lee, Myoung-Gyu

    2016-08-01

    Formability increase in non-conventional forming profiles programmed in the servo-press was investigated using finite element analysis. As an application, forming experiment on a 0.15-mm-thick ferritic stainless steel sheet for a bipolar plate, a primary component of a proton exchange membrane fuel cell, was conducted. Four different forming profiles were considered to investigate the effects of forming profiles on formability and shape accuracy. The four motions included conventional V motion, holding motion, W motion, and oscillating motion. Among the four motions, the holding motion, in which the slide was held for a certain period at the bottom dead point, led to the best formability. Finite element simulations were conducted to validate the experimental results and to probe the formability improvement in the non-conventional forming profiles. A creep model to address stress relaxation effect along with tool elastic recovery was implemented using a user-material subroutine, CREEP in ABAQUS finite element software. The stress relaxation and variable contact conditions during the holding and oscillating profiles were found to be the main mechanism of formability improvement.

  3. Looking for a Person-Centered Medicine: Non Conventional Medicine in the Conventional European and Italian Setting

    Directory of Open Access Journals (Sweden)

    Paolo Roberti di Sarsina

    2011-01-01

    Full Text Available In Italy, the use of non conventional medicines (NCMs is spreading among people as in the rest of Europe. Sales of alternative remedies are growing, and likewise the number of medical doctors (MDs who practise NCM/complementary and alternative medicine (CAM. However, in Italy as in other countries of the European Union, at the present time the juridical/legal status of NCM/CAM is not well established, mainly due to the lack of any national law regulating NCM/CAM professional training, practice and public supply and the absence of government-promoted scientific research in this field. This is an obstacle to safeguarding the patient's interests and freedom of choice, especially now that dissatisfaction with biomedicine is inclining more and more people to look for a holistic and patient-centered form of medicine.

  4. Single-parenthood by choice: Children’s socialization processes into a non-conventional family model

    Directory of Open Access Journals (Sweden)

    David Poveda

    2011-07-01

    Full Text Available In this article we present part of our findings from a research project focused on single-parent families by choice. The study collected data in three autonomous communities in Spain and includes interviews with mothers involved in single parent-projects (through adoption, foster parenting, assisted reproductive technologies or sexual fertilization through a known donor and their children about their family experiences, observations in different formative, associative and virtual spaces in which these families participate and a compilation of different documents on parenthood by choice. We focus on the way in which the children we have studied build their own non-conventional family model. We understand the construction of this model as a process of co-construction of the child's subjectivity in which mothers and other socializing agents play an active role.

  5. Application of Metal Oxide Surge Arrester on the Non-Conventional Chaotic Ferroresonance Oscillation in Voltage Transformers

    Directory of Open Access Journals (Sweden)

    Hamid Radmanesh

    2012-09-01

    Full Text Available In this study the effect of MOSA on controlling of the non-conventional ferroresonance overvoltage in the iron core voltage transformer is studied. It is expected that MOSA can generally damp ferroresonance overvoltages. Time-domain study is used to analyze this effect. Study is done on a voltage transformer rated 100VA, 275 kV. The magnetization characteristic of the transformer coil is modeled by a single-parameter twoterm polynomial with q = 7 degree of nonlinearity. Core loss is modeled by linear resistance. Simulation results show that connecting the MOSA in parallel to the voltage transformer, shows a great controlling effect of the ferroresonance oscillations. Phase plane, time domain voltage waveforms, FFT analysis and bifurcation diagrams are also given. Significant effect on settling down to the chaos, the range of parameter values that may lead to ferroresonance overvoltages and controlling these phenomena are obtained and presented.

  6. [Comparison of conventional and non-conventional serological tests for the diagnosis of imported Chagas disease in Spain].

    Science.gov (United States)

    Flores-Chávez, María; Cruz, Israel; Rodríguez, Mercedes; Nieto, Javier; Franco, Elena; Gárate, Teresa; Cañavate, Carmen

    2010-05-01

    Trypanosoma cruzi infection is a major imported parasitic disease in Spain, because of the increase of immigrants from endemic areas. Since the laboratory diagnosis during the chronic phase is based on detection of anti-T. cruzi IgG antibodies, our aims were to compare 10 tests for determining anti-T. cruzi antibodies, to assess their cross-reactivity with related diseases, and to evaluate the rk39-ELISA and IFAT-Leishmania tests as tools for the differential diagnosis of leishmaniasis due to Leishmania infantum. A total of 223 sera were tested: 40 had been previously characterized by Qpanel, and 183 were obtained from the serum library of the Parasitology Department, Centro Nacional de Microbiología (66 chagasic, 97 healthy, 30 visceral leishmaniasis, and 30 malaria). Samples were examined using in-house IFAT and ELISA, 5 commercial ELISAs (Certest/Abbot Laboratories/BiosChile; Ortho Clinical Diagnostics; BLK Diagnostic; bioMérieux; and Biokit), particle gel agglutination (ID-PaGIA), and two immunochromatographic assays (Operon and CTK Biotech). The last 4 tests are based in recombinant antigens (non-conventional tests). The IFAT and ELISAs showed a sensitivity of 97% to 100%. The immunochromatographic tests had somewhat lower sensitivity (92%-96%). All non-conventional tests presented a smaller number of cross-reactions. Leishmania-Rk39-ELISA did not show cross-reactivity with chagasic sera. In general, our results confirm the data obtained by other authors. The sensitivity of ELISA is higher than other tests; therefore, these techniques would be the most appropriate for screening of T. cruzi infection. A suitable approach is the combination of a test using total antigen with another based on either recombinant antigens or synthetic peptides. (c) 2009 Elsevier España, S.L. All rights reserved.

  7. Non-conventional cement-based composites reinforced with vegetable fibers: A review of strategies to improve durability

    Directory of Open Access Journals (Sweden)

    Santos, S. F.

    2015-03-01

    Full Text Available The present review shows the state-of-art on the approachs about improving the processing, physical- mechanical performance and durability of non-conventional fiber-cement composites. The objective of this review is to show some of these strategies to mitigate the degradation of the vegetable fibers used as reinforcement in cost-effective and non-conventional fiber-cement and, consequently, to improve their mechanical and durability properties for applications in the housing construction. Beyond the introduction about vegetable fibers, the content of this review is divided in the following sections: (i surface modification of the fibers; (ii improving fiber-to-cement interface; (iii natural pozzolans; (iv accelerated carbonation; (v applications of nanoscience; and (vi principles of functionally graded materials and extrusion process were briefly discussed with focus on future research needs.La presente revisión explora la actualidad en el campo de los compuestos de fibrocemento no convencionales en relación a mejoras en el proceso productivo, el rendimiento físico-mecánico y la durabilidad. El objetivo de esta revisión es exponer algunas estrategias para mitigar la degradación de las fibras vegetales utilizadas como refuerzo en fibrocementos no convencionales y rentables, obteniendo en consecuencia una mejoría en el rendimiento de sus propiedades mecánicas y durabilidad para su aplicación en el área de la construcción de viviendas. Además de la introducción en relación a las fibras vegetales, el contenido de esta revisión se divide en las siguientes secciones: (i modificación de la superficie de las fibras; (ii mejoramiento de la interfaz fibra-cemento; (iii puzolanas naturales; (iv carbonatación acelerada; (v aplicaciones de la nanociencia; y (vi principios de los materiales funcionalmente graduados y el proceso de extrusión fueron discutidos brevemente con un enfoque a investigaciones futuras.

  8. Mechanical instability

    CERN Document Server

    Krysinski, Tomasz

    2013-01-01

    This book presents a study of the stability of mechanical systems, i.e. their free response when they are removed from their position of equilibrium after a temporary disturbance. After reviewing the main analytical methods of the dynamical stability of systems, it highlights the fundamental difference in nature between the phenomena of forced resonance vibration of mechanical systems subjected to an imposed excitation and instabilities that characterize their free response. It specifically develops instabilities arising from the rotor-structure coupling, instability of control systems, the se

  9. Collective instabilities

    Energy Technology Data Exchange (ETDEWEB)

    K.Y. Ng

    2003-08-25

    The lecture covers mainly Sections 2.VIII and 3.VII of the book ''Accelerator Physics'' by S.Y. Lee, plus mode-coupling instabilities and chromaticity-driven head-tail instability. Besides giving more detailed derivation of many equations, simple interpretations of many collective instabilities are included with the intention that the phenomena can be understood more easily without going into too much mathematics. The notations of Lee's book as well as the e{sup jwt} convention are followed.

  10. Biomass Briquette Production: A Propagation of Non-Convention Technology and Future of Pollution Free Thermal Energy Sources

    Directory of Open Access Journals (Sweden)

    Manoj Kumar Sharma

    2015-02-01

    Full Text Available Biomass briquettes are a biofuel substitute to coal and charcoal. Briquettes are mostly used in the developing world where cooking fuels are not as easily available. Briquettes are used to heat industrial boilers in order to produce electricity from steam. The briquettes are con-fired with coal in order to create the heat supplied to the boiler. People have been using biomass briquettes since before recorded history. Biomass briquettes are made from agriculture waste and are a replacement for fossils fuels such as oil or coal, and can be used to heat boiler in manufacturing plants. Biomass briquettes are a renewable source of energy and avoid adding fossils carbon to the atmosphere. The extrusion production technology of briquettes is the process of extrusion screw wastes (straw, sunflower husks, buckwheat, etc. or finely shredded wood waste (sawdust under high pressure. There is a tremendous scope to bring down the waste of convention energy sources to a considerable level through the development, propagation of non-convention briquettes technology i.e. briquettes machine , briquettes plant, biomass briquettes plant for production of agro residue briquettes to meet thermal energy requirement . Therefore this substitute energy medium is given national priority as appears to be the only permanent solution into restriction of the national laws and avoid pollutions.

  11. Optimization of the magnetic horn for the nuSTORM non-conventional neutrino beam using the genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Liu, A., E-mail: aoliu@fnal.gov [Fermilab, P.O. Box 500, Batavia, IL 60510 (United States); Bross, A.; Neuffer, D. [Fermilab, P.O. Box 500, Batavia, IL 60510 (United States)

    2015-09-11

    This paper describes the strategy for optimizing the magnetic horn for the neutrinos from STORed Muons (nuSTORM) facility. The nuSTORM magnetic horn is the primary collection device for the secondary particles generated by bombarding a solid target with 120 GeV protons. As a consequence of the non-conventional beamline designed for nuSTORM, the requirements on the horn are different from those for a conventional neutrino beamline. At nuSTORM, muons decay while circulating in the storage ring, and the detectors are placed downstream of the production straight so as to be exposed to the neutrinos from muon decay. nuSTORM aims at precisely measuring the neutrino cross sections, and providing a definitive statement about the existence of sterile neutrinos. The nuSTORM horn aims at focusing the pions into a certain phase space so that more muons from pion decay can be accepted by the decay ring. The paper demonstrates a numerical method that was developed to optimize the horn design to gain higher neutrino flux from the circulating muons. A Genetic Algorithm (GA) was applied to the simultaneous optimization of the two objectives in this study. The application of the technique discussed in this paper is not limited to either the nuSTORM facility or muon based facilities, but can be used for other neutrino facilities that use magnetic horns as collection devices.

  12. Looking beyond Saccharomyces: the potential of non-conventional yeast species for desirable traits in bioethanol fermentation.

    Science.gov (United States)

    Radecka, Dorota; Mukherjee, Vaskar; Mateo, Raquel Quintilla; Stojiljkovic, Marija; Foulquié-Moreno, María R; Thevelein, Johan M

    2015-09-01

    Saccharomyces cerevisiae has been used for millennia in the production of food and beverages and is by far the most studied yeast species. Currently, it is also the most used microorganism in the production of first-generation bioethanol from sugar or starch crops. Second-generation bioethanol, on the other hand, is produced from lignocellulosic feedstocks that are pretreated and hydrolyzed to obtain monomeric sugars, mainly D-glucose, D-xylose and L-arabinose. Recently, S. cerevisiae recombinant strains capable of fermenting pentose sugars have been generated. However, the pretreatment of the biomass results in hydrolysates with high osmolarity and high concentrations of inhibitors. These compounds negatively influence the fermentation process. Therefore, robust strains with high stress tolerance are required. Up to now, more than 2000 yeast species have been described and some of these could provide a solution to these limitations because of their high tolerance to the most predominant stress conditions present in a second-generation bioethanol reactor. In this review, we will summarize what is known about the non-conventional yeast species showing unusual tolerance to these stresses, namely Zygosaccharomyces rouxii (osmotolerance), Kluyveromyces marxianus and Ogataea (Hansenula) polymorpha (thermotolerance), Dekkera bruxellensis (ethanol tolerance), Pichia kudriavzevii (furan derivatives tolerance) and Z. bailii (acetic acid tolerance).

  13. The Forgotten Virulence Factor: The 'non-conventional' Hemolysin TlyA And Its Role in Helicobacter pylori Infection.

    Science.gov (United States)

    Javadi, Mohammad Bagher; Katzenmeier, Gerd

    2016-12-01

    Helicobacter pylori is a human-specific Gram-negative pathogenic bacterium which colonizes the gastric mucosal layer in the stomach causing diseases such as peptic ulcer, adenocarcinoma, and gastric lymphoma. It is estimated that approximately half of the world's population is infected with H. pylori making it the most intensively characterized microbial pathogen up to now. Hemolysis has been suggested to significantly contribute to colonization of the stomach and disease progression by H. pylori. In a number of earlier studies, TlyA was characterized as a putative pore-forming cytolysin. Although a few observations in the literature suggest a role for TlyA as significant virulence factor of H. pylori, the molecular and structural characterization of this protein is much curtailed at present. Given the intensive characterization of numerous H. pylori virulence factors over the past decade, surprisingly little information exists for the TlyA toxin and its significance for pathogenesis. This review provides a brief overview on microbial hemolysis and its role for pathogenesis and discusses recent research efforts aimed at an improved understanding of the role of the 'non-conventional' hemolysin and its associated RNA methyltransferase TlyA from H. pylori.

  14. Sustainable and non-conventional monitoring systems to mitigate natural hazards in low income economies: the 4onse project approach.

    Science.gov (United States)

    Cannata, Massimiliano; Ratnayake, Rangajeewa; Antonovic, Milan; Strigaro, Daniele

    2017-04-01

    Environmental monitoring systems in low economies countries are often in decline, outdated or missing with the consequence that there is a very scarce availability and accessibility to these information that are vital for coping and mitigating natural hazards. Non-conventional monitoring systems based on open technologies may constitute a viable solution to create low cost and sustainable monitoring systems that may be fully developed, deployed and maintained at local level without lock-in dependances on copyrights or patents or high costs of replacements. The 4onse research project , funded under the Research for Development program of the Swiss National Science Foundation and the Swiss Office for Development and Cooperation, propose a complete monitoring system that integrates Free & Open Source Software, Open Hardware, Open Data, and Open Standards. After its engineering, it will be tested in the Deduru Oya catchment (Sri Lanka) to evaluate the system and develop a water management information system to optimize the regulation of artificial basins levels and mitigate flash floods. One of the objective is to better scientifically understand strengths, criticalities and applicabilities in terms of data quality; system durability; management costs; performances; sustainability. Results, challenges and experiences from the first six months of the projects will be presented with particular focus on the activities of synergies building and data collection and dissemination system advances.

  15. Simple and sensitive detection of aflatoxin B1 within five minute using a non-conventional competitive immunosensing mode.

    Science.gov (United States)

    Lin, Youxiu; Zhou, Qian; Lin, Yuping; Tang, Dianyong; Chen, Guonan; Tang, Dianping

    2015-12-15

    A novel competitive-type immunosensing strategy based on target-induced displacement reaction with antibody-functionalized mesoporous carbon (MSC) nanoparticles was designed for sensitive and rapid electrochemical detection of aflatoxin B1 (AFB1, used as a model) on the Nafion-functionalized sensing interface. Electroactive thionine molecules were initially decorated to the mesoporous carbon, and polyclonal anti-AFB1 antibody was then covalently conjugated to the nanostructures. The immunosensor was simply prepared via the electrostatic interaction between negatively charged Nafion film and positively charged anti-AFB1 antibody accompanying the nanostructures. The electrochemical signal originated from the carried thionine to mesoporous carbon. Upon target AFB1 introduction, the analyte reacted with the labeled anti-AFB1 antibody on the MSC based on specific antigen-antibody reaction and induced the dissociation of thionine-MSN nanostructures from the sensing interface, thus decreasing the cathodic current of the carried thionine molecules. Under optimal conditions, the immunosensor exhibited good electrochemical responses for determination of target AFB1 at a concentration as low as 3.0 pg mL(-1) (3.0 ppt). Importantly, the non-conventional sensing system provides a promising immunosensing strategy for rapid screening of small molecules because of its simplicity, low cost and sensitivity without the needs of sample separation and washing step.

  16. Mesoscale analysis and simulation of heavy rainfall in Shanghai urban area by using non-conventional data

    Institute of Scientific and Technical Information of China (English)

    QI Linlin; ZHAO Sixiong

    2003-01-01

    In this paper, a local record severe rainfall since 1949 occurring in the Shanghai urban area on 5-6 August, 2001 is investigated by using non-conventional observational data provided by the "973" basic research project of China, including automatic meteorological stations data, wind profiler data, Doppler radar echoes and GMS5 satellite data and NCEP data. By analyzing, it is revealed: (1) the heavy rainfall, caused by a serious of mesoscale βconvective cloud clusters developing inside the landing tropical depression (TD), occurred suddenly with the typical characteristics of urban heavy rainfall disaster; (2) the landing tropical depression, moved eastward to Shanghai and re-intensified before entering the sea, was very favorable for the occurrence of the heavy rainfall in Shanghai; (3) there may exists the interaction of different scale systems between the tropical depression and mesoscale convective cloud clusters; and (4) the various advanced intensive data contribute importantly to detect earlier and predict successfully the urban meteorological disasters.

  17. A review of the advancements in probiotic delivery: Conventional vs. non-conventional formulations for intestinal flora supplementation.

    Science.gov (United States)

    Govender, Mershen; Choonara, Yahya E; Kumar, Pradeep; du Toit, Lisa C; van Vuuren, Sandy; Pillay, Viness

    2014-02-01

    Probiotic delivery systems are widely used nutraceutical products for the supplementation of natural intestinal flora. These delivery systems vary greatly in effectiveness to exert health benefits for a patient. Probiotic delivery systems can be categorized into conventional, pharmaceutical formulations, and non-conventional, mainly commercial food-based, products. The degree of health benefits provided by these probiotic formulations varies in their ability to deliver viable, functional bacteria in large enough numbers (effectiveness), to provide protection against the harsh effects of the gastric environment and intestinal bile (in vivo protection), and to survive formulation processes (viability). This review discusses the effectiveness of these probiotic delivery systems to deliver viable functional bacteria focusing on the ability to protect the encapsulated probiotics during formulation process as well as against harsh physiological conditions through formulation enhancements using coatings and polymer enhancements. A brief overview on the health benefits of probiotics, current formulation, patient and legal issues facing probiotic delivery, and possible recommendations for the enhanced delivery of probiotic bacteria are also provided. Newer advanced in vitro analyses that can accurately determine the effectiveness of a probiotic formulation are also discussed with an ideal probiotic delivery system hypothesized through a combination of the two probiotic delivery systems described.

  18. Towards non-conventional methods of designing register-based epidemiological studies: An application to pediatric research.

    Science.gov (United States)

    Gong, Tong; Brew, Bronwyn; Sjölander, Arvid; Almqvist, Catarina

    2017-07-01

    Various epidemiological designs have been applied to investigate the causes and consequences of fetal growth restriction in register-based observational studies. This review seeks to provide an overview of several conventional designs, including cohort, case-control and more recently applied non-conventional designs such as family-based designs. We also discuss some practical points regarding the application and interpretation of family-based designs. Definitions of each design, the study population, the exposure and the outcome measures are briefly summarised. Examples of study designs are taken from the field of low birth-weight research for illustrative purposes. Also examined are relative advantages and disadvantages of each design in terms of assumptions, potential selection and information bias, confounding and generalisability. Kinship data linkage, statistical models and result interpretation are discussed specific to family-based designs. When all information is retrieved from registers, there is no evident preference of the case-control design over the cohort design to estimate odds ratios. All conventional designs included in the review are prone to bias, particularly due to residual confounding. Family-based designs are able to reduce such bias and strengthen causal inference. In the field of low birth-weight research, family-based designs have been able to confirm a negative association not confounded by genetic or shared environmental factors between low birth weight and the risk of asthma. We conclude that there is a broader need for family-based design in observational research as evidenced by the meaningful contributions to the understanding of the potential causal association between low birth weight and subsequent outcomes.

  19. Reactive transport modelling to infer changes in soil hydraulic properties induced by non-conventional water irrigation

    Science.gov (United States)

    Valdes-Abellan, Javier; Jiménez-Martínez, Joaquín; Candela, Lucila; Jacques, Diederik; Kohfahl, Claus; Tamoh, Karim

    2017-06-01

    The use of non-conventional water (e.g., treated wastewater, desalinated water) for different purposes is increasing in many water scarce regions of the world. Its use for irrigation may have potential drawbacks, because of mineral dissolution/precipitation processes, such as changes in soil physical and hydraulic properties (e.g., porosity, permeability), modifying infiltration and aquifer recharge processes or blocking root growth. Prediction of soil and groundwater impacts is essential for achieving sustainable agricultural practices. A numerical model to solve unsaturated water flow and non-isothermal multicomponent reactive transport has been modified implementing the spatio-temporal evolution of soil physical and hydraulic properties. A long-term process simulation (30 years) of agricultural irrigation with desalinated water, based on a calibrated/validated 1D numerical model in a semi-arid region, is presented. Different scenarios conditioning reactive transport (i.e., rainwater irrigation, lack of gypsum in the soil profile, and lower partial pressure of CO2 (pCO2)) have also been considered. Results show that although boundary conditions and mineral soil composition highly influence the reactive processes, dissolution/precipitation of carbonate species is triggered mainly by pCO2, closely related to plant roots. Calcite dissolution occurs in the root zone, precipitation takes place under it and at the soil surface, which will lead a root growth blockage and a direct soil evaporation decrease, respectively. For the studied soil, a gypsum dissolution up to 40 cm depth is expected at long-term, with a general increase of porosity and hydraulic conductivity.

  20. Finding Multiple Internal Rates of Return for a Project with Non-Conventional Cash Flows: Utilizing Popular Financial/Graphing Calculators and Spreadsheet Software

    Science.gov (United States)

    Chen, Jeng-Hong

    2008-01-01

    This study demonstrates that a popular graphing calculator among students, TI-83 Plus, has a powerful function to draw the NPV profile and find the accurate multiple IRRs for a project with non-conventional cash flows. However, finance textbooks or related supplementary materials do not provide students instructions for this part. The detailed…

  1. Finding Multiple Internal Rates of Return for a Project with Non-Conventional Cash Flows: Utilizing Popular Financial/Graphing Calculators and Spreadsheet Software

    Science.gov (United States)

    Chen, Jeng-Hong

    2008-01-01

    This study demonstrates that a popular graphing calculator among students, TI-83 Plus, has a powerful function to draw the NPV profile and find the accurate multiple IRRs for a project with non-conventional cash flows. However, finance textbooks or related supplementary materials do not provide students instructions for this part. The detailed…

  2. Recombination instability

    DEFF Research Database (Denmark)

    D'Angelo, N.

    1967-01-01

    A recombination instability is considered which may arise in a plasma if the temperature dependence of the volume recombination coefficient, alpha, is sufficiently strong. Two cases are analyzed: (a) a steady-state plasma produced in a neutral gas by X-rays or high energy electrons; and (b) an af...

  3. [Carpal instability].

    Science.gov (United States)

    Redeker, J; Vogt, P M

    2011-01-01

    Carpal instability can be understood as a disturbed anatomical alignment between bones articulating in the carpus. This disturbed balance occurs either only dynamically (with movement) under the effect of physiological force or even statically at rest. The most common cause of carpal instability is wrist trauma with rupture of the stabilizing ligaments and adaptive misalignment following fractures of the radius or carpus. Carpal collapse plays a special role in this mechanism due to non-healed fracture of the scaphoid bone. In addition degenerative inflammatory alterations, such as chondrocalcinosis or gout, more rarely aseptic bone necrosis of the lunate or scaphoid bones or misalignment due to deposition (Madelung deformity) can lead to wrist instability. Under increased pressure the misaligned joint surfaces lead to bone arrosion with secondary arthritis of the wrist. In order to arrest or slow down this irreversible process, diagnosis must occur as early as possible. Many surgical methods have been thought out to regain stability ranging from direct reconstruction of the damaged ligaments, through ligament replacement to partial stiffening of the wrist joint.

  4. FINANCIAL INSTABILITY AND POLITICAL INSTABILITY

    Directory of Open Access Journals (Sweden)

    Ionescu Cristian

    2012-12-01

    Full Text Available There is an important link between the following two variables: financial instability and political instability. Often, the link is bidirectional, so both may influence each other. This is way the lately crisis are becoming larger and increasingly complex. Therefore, the academic environment is simultaneously talking about economic crises, financial crises, political crises, social crises, highlighting the correlation and causality between variables belonging to the economic, financial, political and social areas, with repercussions and spillover effects that extend from one area to another. Given the importance, relevance and the actuality of the ones described above, I consider that at least a theoretical analysis between economic, financial and political factors is needed in order to understand the reality. Thus, this paper aims to find links and connections to complete the picture of the economic reality.

  5. Do Farmers Using Conventional and Non-Conventional Systems of Agriculture Have Different Perceptions of the Diversity of Wild Birds? Implications for Conservation.

    Science.gov (United States)

    Silva-Andrade, Horasa Lima; de Andrade, Luciano Pires; Muniz, Lauana Souza; Telino-Júnior, Wallace Rodrigues; Albuquerque, Ulysses Paulino; Lyra-Neves, Rachel Maria

    2016-01-01

    Farmers' perceptions of birds' interactions with agricultural production systems are fundamental to species conservation efforts. In the present study, we evaluated the perceptions of birds held by farmers who engage in conventional and non-conventional agricultural production processes and the implications of potential differences in these perceptions on species conservation. To accomplish this, data were collected using questionnaires, semi-structured interviews, and other complementary sources of information gathered from 191 farmers in northeastern Brazil. Although some similarities were identified among the farmers in their perceptions and local ecological knowledge (LEK) of birds, differences existed between the conventional and non-conventional farmers in their attitudes toward, conflicts with, and usage of bird species. Compared to the conventional farmers, the non-conventional farmers could identify more bird species, possessed more favorable attitudes toward birds, and engaged in practices more beneficial to the conservation of avifauna. The perceptions that were identified were related to the type of agriculture practiced, and such perceptions may affect the conservation of bird species. Therefore, the adoption of certain agricultural practices has important implications for conservation. Our results indicate the need for investment in public policies, programs and actions that account for farmers' knowledge and perceptions. Such investments will contribute to the development and adoption of practices supporting wild bird conservation in agricultural areas.

  6. Do Farmers Using Conventional and Non-Conventional Systems of Agriculture Have Different Perceptions of the Diversity of Wild Birds? Implications for Conservation.

    Directory of Open Access Journals (Sweden)

    Horasa Lima Silva-Andrade

    Full Text Available Farmers' perceptions of birds' interactions with agricultural production systems are fundamental to species conservation efforts. In the present study, we evaluated the perceptions of birds held by farmers who engage in conventional and non-conventional agricultural production processes and the implications of potential differences in these perceptions on species conservation. To accomplish this, data were collected using questionnaires, semi-structured interviews, and other complementary sources of information gathered from 191 farmers in northeastern Brazil. Although some similarities were identified among the farmers in their perceptions and local ecological knowledge (LEK of birds, differences existed between the conventional and non-conventional farmers in their attitudes toward, conflicts with, and usage of bird species. Compared to the conventional farmers, the non-conventional farmers could identify more bird species, possessed more favorable attitudes toward birds, and engaged in practices more beneficial to the conservation of avifauna. The perceptions that were identified were related to the type of agriculture practiced, and such perceptions may affect the conservation of bird species. Therefore, the adoption of certain agricultural practices has important implications for conservation. Our results indicate the need for investment in public policies, programs and actions that account for farmers' knowledge and perceptions. Such investments will contribute to the development and adoption of practices supporting wild bird conservation in agricultural areas.

  7. The role of MHD instabilities in the improved H-mode scenario

    Energy Technology Data Exchange (ETDEWEB)

    Flaws, Asher

    2009-02-16

    Recently a regime of tokamak operation has been discovered, dubbed the improved H-mode scenario, which simultaneously achieves increased energy confinement and stability with respect to standard H-mode discharges. It has been suggested that magnetohydrodynamic (MHD) instabilities play some role in establishing this regime. In this thesis MHD instabilities were identified, characterised, and catalogued into a database of improved H-mode discharges in order to statistically examine their behaviour. The onset conditions of MHD instabilities were compared to existing models based on previous H-mode studies. Slight differences were found, most notably a reduced {beta}{sub N} onset threshold for the frequently interrupted regime for neoclassical tearing modes (NTM). This reduced threshold is due to the relatively low magnetic shear of the improved H-mode regime. This study also provided a first-time estimate for the seed island size of spontaneous onset NTMs, a phenomenon characteristic of the improved H-mode scenario. Energy confinement investigations found that, although the NTM impact on confinement follows the same model applicable to other operating regimes, the improved H-mode regime acts to mitigate the impact of NTMs by limiting the saturated island sizes for NTMs with toroidal mode number n {>=} 2. Surprisingly, although a significant loss in energy confinement is observed during the sawtooth envelope, it has been found that discharges containing fishbones and low frequency sawteeth achieve higher energy confinement than those without. This suggests that fishbone and sawtooth reconnection may indeed play a role in establishing the high confinement regime. It was found that the time evolution of the central magnetic shear consistently locks in the presence of sawtooth and fishbone reconnection. Presumably this is due to the periodic redistribution of the central plasma current, an effect which is believed to help establish and maintain the characteristic current

  8. A quality improvement study using fishbone analysis and an electronic medical records intervention to improve care for children with asthma.

    Science.gov (United States)

    Gold, Jonathan; Reyes-Gastelum, David; Turner, Jane; Davies, H Dele

    2014-01-01

    Despite expert guidelines, gaps persist in quality of care for children with asthma. This study sought to identify barriers and potential interventions to improve compliance to national asthma prevention guidelines at a single academic pediatric primary care clinic. Using the plan-do-check-act (PDCA) quality improvement framework and fishbone analysis, several barriers to consistent asthma processes and possible interventions were identified by a group of key stakeholders. Two interventions were implemented using the electronic medical record (EMR). Physician documentation of asthma quality measures were analyzed before intervention and during 2 subsequent time points over 16 months. Documentation of asthma action plans (core group P asthma care in a pediatric primary care setting.

  9. Reactivity of non conventional supported mixed sulfides for hydro-treatment reactions; Reactivite de sulfures mixtes supportes non conventionnels pour les reactions d`hydrotraitement

    Energy Technology Data Exchange (ETDEWEB)

    Quartararo, J.

    1996-11-07

    The properties of non conventional NiM sulfides (M: Mn, Fe, Cu,Zn, Re, Ru) was evaluated for two hydro treating reactions: hydro desulfurization (HDS) of dibenzo thiophene and benzo thiophene and hydrogenation (HYD) of cyclohexyl. The reactions were t first studied on Ni, Mo and NiMo sulfide catalysts. The influence of the nature of the molecule on the magnitude of promoting effect was demonstrated. The non conventional mono-metallic and bimetallic catalysts studied in this work were characterized by XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy) and TEM (transmission electron microscopy). Ni exhibits a negative effect on the activity of Mn, Cu, Zn and Re sulfide catalysts. This effect could be related to the formation of two separated sulfide phases: base metal sulfide and nickel sulfide. Nevertheless, a promoting effect was found in NiRu catalyst. In this catalyst, the Ru and the Ni are in a mixed phase. The results of this study demonstrate the importance of the type of metal associated to the nickel for the promoting effect and relate this effect to the formation of a mixed phase. (author)

  10. Structure and photoluminescence properties of fishbone-like PbMoO4 nanostructures obtained via the surfactant-assisted hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    Runping Jia; Kangsheng Zheng

    2012-01-01

    Fishbone-like PbMoO4 nanostructures are successfully obtained via the surfactant-assisted hydrothermal method at 160 ℃.Polyethylene glycol (PEG2000) is used as the template agent.The nanostructures are characterized via X-ray diffraction,field-emission scanning electron microscopy,Fourier transform infrared spectroscopy,ultraviolet-visible light (UV-Vis) spectroscopy,and photoluminescence (PL) measurements.The PbMoO4 morphology is highly associated with the molecular nature of PEG2000.PbMoO4 nanoparticles obtained from PEG2000 have a fishbone-shaped,scheelite-type tetragonal structure,in which numerous secondary branches vertically grow on both sides of the main stem.The structures exhibit broad PL emission bands with the maximum at 306 and 390 nm when excited at 250 nm.In addition,the UV-Vis absorption edge of the structures is in the 280 to 310 nm region,and the band gap is 4.07 eV.A plausible formation mechanism for the fishbone-like PbMoO4 nanostructures is also discussed.

  11. Microstructure changes during non-conventional heat treatment of thin Ni-Ti wires by pulsed electric current studied by transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Delville, R., E-mail: remi.delville@ua.ac.be [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Malard, B.; Pilch, J.; Sittner, P. [Institute of Physics, Na Slovance 2, 182 21 Praha (Czech Republic); Schryvers, D. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2010-08-15

    Transmission electron microscopy, electrical resistivity measurements and mechanical testing were employed to investigate the evolution of microstructure and functional superelastic properties of 0.1 mm diameter as-drawn Ni-Ti wires subjected to a non-conventional heat treatment by controlled electric pulse currents. This method enables a better control of the recovery and recrystallization processes taking place during the heat treatment and accordingly a better control on the final microstructure. Using a stepwise approach of millisecond pulse annealing, it is shown how the microstructure evolves from a severely deformed state with no functional properties to an optimal nanograined microstructure (20-50 nm) that is partially recovered through polygonization and partially recrystallized and that has the best functional properties. Such a microstructure is highly resistant against dislocation slip upon cycling, while microstructures annealed for longer times and showing mostly recrystallized grains were prone to dislocation slip, particularly as the grain size exceeds 200 nm.

  12. Development and optimisation of a non conventional extraction process of natural dye from olive solid waste using response surface methodology (RSM).

    Science.gov (United States)

    Elksibi, Imen; Haddar, Wafa; Ben Ticha, Manel; Gharbi, Rafik; Mhenni, Mohamed F

    2014-10-15

    Dyes obtained from different natural sources have emerged as an important alternative to synthetic dyes. In this study, optimisation of natural colorant non-conventional extraction technique from olive waste was investigated using response surface methodology. The combined effects of extraction conditions on total phenolic content (TPC) and relative color strength (K/S) were studied using a three-level three-factor Box-Behnken design. The optimum conditions for dye extraction were found to be 0.14mol/L, 62.11min, 71.23°C and 4.5g for sodium hydroxide concentration, extraction time, temperature, and mass of the waste, respectively. The efficiency of extraction under these optimum conditions was found to be 1133.86mg/L of phenolics and relative colour strength (K/S) equal to 23.22. Further, Fourier Transform Infrared Spectroscopy was used to identify the major chemical groups in the extracted dye.

  13. An overview on advances of amylases production and their use in the production of bioethanol by conventional and non-conventional processes

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Aline M. [Petrobras, Biotechnology Division, Research and Development Center, Ilha do Fundao, Rio de Janeiro (Brazil); Castilho, Leda R. [Federal University of Rio de Janeiro, COPPE, Chemical Engineering Program, Rio de Janeiro (Brazil); Freire, Denise M.G. [Federal University of Rio de Janeiro, Institute of Chemistry, Rio de Janeiro (Brazil)

    2011-12-15

    Amylases comprise some of the most reported groups of enzymes for the production of biofuels. Such enzymes from fungal and bacterial origins have been used at commercial scale for decades, using conventional processes (dry grinding and wet milling) for the production of bioethanol, and most recently they have been applied in a non-conventional process named cold starch hydrolysis (or granular starch hydrolysis). This review covers the feedstocks that can be used for the production of these enzymes, the state of the art of the enzyme production processes over the last decade, as well as the main aspects of their application for the production of bioethanol. Under the concluding remarks we discuss future trends for the optimization of such technologies. (orig.)

  14. Non-conventional electrical machines

    CERN Document Server

    Rezzoug, Abderrezak

    2013-01-01

    The developments of electrical machines are due to the convergence of material progress, improved calculation tools, and new feeding sources. Among the many recent machines, the authors have chosen, in this first book, to relate the progress in slow speed machines, high speed machines, and superconducting machines. The first part of the book is dedicated to materials and an overview of magnetism, mechanic, and heat transfer.

  15. Electron heat flux instability

    Science.gov (United States)

    Saeed, Sundas; Sarfraz, M.; Yoon, P. H.; Lazar, M.; Qureshi, M. N. S.

    2017-02-01

    The heat flux instability is an electromagnetic mode excited by a relative drift between the protons and two-component core-halo electrons. The most prominent application may be in association with the solar wind where drifting electron velocity distributions are observed. The heat flux instability is somewhat analogous to the electrostatic Buneman or ion-acoustic instability driven by the net drift between the protons and bulk electrons, except that the heat flux instability operates in magnetized plasmas and possesses transverse electromagnetic polarization. The heat flux instability is also distinct from the electrostatic counterpart in that it requires two electron species with relative drifts with each other. In the literature, the heat flux instability is often called the 'whistler' heat flux instability, but it is actually polarized in the opposite sense to the whistler wave. This paper elucidates all of these fundamental plasma physical properties associated with the heat flux instability starting from a simple model, and gradually building up more complexity towards a solar wind-like distribution functions. It is found that the essential properties of the instability are already present in the cold counter-streaming electron model, and that the instability is absent if the protons are ignored. These instability characteristics are highly reminiscent of the electron firehose instability driven by excessive parallel temperature anisotropy, propagating in parallel direction with respect to the ambient magnetic field, except that the free energy source for the heat flux instability resides in the effective parallel pressure provided by the counter-streaming electrons.

  16. Evaluating shoulder instability treatment

    NARCIS (Netherlands)

    van der Linde, J.A.

    2016-01-01

    Shoulder instability common occurs. When treated nonoperatively, the resulting societal costs based on health care utilization and productivity losses are significant. Shoulder function can be evaluated using patient reported outcome measurements (PROMs). For shoulder instability, these include the

  17. Jeans instability in superfluids

    Energy Technology Data Exchange (ETDEWEB)

    Hason, Itamar; Oz, Yaron [Tel-Aviv University, Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv (Israel)

    2014-11-15

    We analyze the effect of a gravitational field on the sound modes of superfluids. We derive an instability condition that generalizes the well-known Jeans instability of the sound mode in normal fluids. We discuss potential experimental implications. (orig.)

  18. Non conventional empirical relations for estimating compressional-wave sonic logs; Relacoes empiricas nao-convencionais para estimativa de perfis sonicos de ondas compressionais

    Energy Technology Data Exchange (ETDEWEB)

    Augusto, Fabricio de O.A. [Observatorio Nacional (ON), Rio de Janeiro, RJ (Brazil). Curso de Pos-graduacao em Geofisica; Martins, Jorge L. [Observatorio Nacional (ON), Rio de Janeiro, RJ (Brazil). Coordenacao da Area de Geofisica

    2008-07-01

    We apply least-squares regression using non-conventional empirical relations for estimating compressional-wave sonic logs (DTP). We investigate the applicability of five expressions which involve exponential functions, with arguments representing effective porosity ({phi}e) estimated from density logs, shaliness (V{sub clay}) estimated from gamma-ray logs (GR) and electrical resistivity (R{sub ILD}) measured by the deep-induction logging tool (ILD). First, we use such physical properties individually, i.e., as the dependence parameter of compressional-wave velocities (V{sub P}), in the argument of the exponential function; then, we combine some of these properties in order to simulate the known interdependency among them. In order to test our methodology, we adopt two vertical wells - hereafter named Poco-A and Poco-B - from 'Campo Escola Namorado', with information of all geophysical well logs necessary to our study in the turbiditic interval from 2950 e 3150 m. In Poco-A, the best fit obtained through least squares for compressional-wave velocities was V{sub P} = 4.657 exp[.1.488 {phi}e - 0.986 V{sub clay} + 5.022 {phi}e V{sub clay} ], with correlation coefficient r = 0.81; in Poco-B, we found V{sub P} 4.209 exp[- 0.658 {phi}e - 0.430 V{sub clay} + 6.620 x 10.4 R{sub ILD} - 0.035 {phi}e V{sub clay} R{sub ILD}], with correlation coefficient r = 0.52. These two non-conventional empirical models take into account the effects of the interdependence between effective porosity, shaliness and electrical resistivity of the rock on Vp (i.e., they incorporate non-linear effects), becoming alternative models for predicting the sonic logs that are incomplete and/or absent in the data set 'Campo Escola Namorado'. (author)

  19. 鱼骨图在封存急救车管理中的应用%The application of fishbone diagram in the vehicle management in emergency storage

    Institute of Scientific and Technical Information of China (English)

    张姗姗

    2015-01-01

    目的:评价鱼骨图在封存急救车管理中的应用效果。方法:采用鱼骨图示意图分析急救车封条管理缺陷,并进行针对性的改进。结果:改进后,分管护士检查不到位发生率、接班不规范发生率、问题例次率低于改进前,差异具有统计学意义(P<0.05)。结论:通过鱼骨图分析,深入剖析了常见问题的根由,进行针对性改进后,封存急救车管理问题发生率显著降低。%Objective To evaluate the application effect of fishbone in storage management of emergency vehicles. Methods Using the fishbone diagram analysis of ambulance seal management defects, and make targeted improvements. Results Improved, in charge of a nurse checks does not reach the designated position incidence, succession is not standardized incidence, cases of times lower than the rate improvement, the difference has statistical significance (P<0.05). Conclusion Through the fishbone diagram analysis, in-depth analysis of the common problems and were improved for storage of emergency vehicle management incidence rate increased significantly.

  20. Non-conventional interaction contributions in permalloy/NiO composite thin films deduced from their static and dynamic magnetization behavior

    Energy Technology Data Exchange (ETDEWEB)

    Zighem, F; Roussigne, Y; Cherif, S-M; Moch, P [Laboratoire des Proprietes Mecaniques et Thermodynamiques des Materiaux, CNRS, Institut Galilee, Universite Paris-Nord, Avenue J-B Clement, 93430 Villetaneuse (France)], E-mail: zighem@galilee.univ-paris13.fr

    2008-03-26

    A comparative study of thin permalloy films (10.4 nm) interfaced with NiO layers of various thicknesses (6 to 47 nm) is presented. The magnetic parameters deduced from different experimental techniques (Brillouin spectroscopy, ferromagnetic resonance and magnetometric (vibrating sample magnetometry and magneto-optical Kerr effect) investigations) show original characteristics which have not been previously evidenced: (i) for most of the samples studied, the exchange bias field is not parallel or perpendicular to the cooling field, in contrast with the in-plane anisotropy field; (ii) the magnetic properties under an out-of-plane applied magnetic field H do not match the calculated ones derived from the usual expression for the density of magnetic energy. We introduce a phenomenological additional term proportional to cos[{alpha}] where {alpha} is the angle between H and the direction normal to the sample: this non-conventional interaction between NiO and permalloy layers allows us to fit all the experimental data.

  1. Production of Flavours and Fragrances via Bioreduction of (4R-(--Carvone and (1R-(--Myrtenal by Non-Conventional Yeast Whole-Cells

    Directory of Open Access Journals (Sweden)

    Benedetta Turchetti

    2013-05-01

    Full Text Available As part of a program aiming at the selection of yeast strains which might be of interest as sources of natural flavours and fragrances, the bioreduction of (4R-(−-carvone and (1R-(−-myrtenal by whole-cells of non-conventional yeasts (NCYs belonging to the genera Candida, Cryptococcus, Debaryomyces, Hanseniaspora, Kazachstania, Kluyveromyces, Lindnera, Nakaseomyces, Vanderwaltozyma and Wickerhamomyces was studied. Volatiles produced were sampled by means of headspace solid-phase microextraction (SPME and the compounds were analysed and identified by gas chromatography–mass spectroscopy (GC-MS. Yields (expressed as % of biotransformation varied in dependence of the strain. The reduction of both (4R-(−-carvone and (1R-(−-myrtenal were catalyzed by some ene-reductases (ERs and/or carbonyl reductases (CRs, which determined the formation of (1R,4R-dihydrocarvone and (1R-myrtenol respectively, as main flavouring products. The potential of NCYs as novel whole-cell biocatalysts for selective biotransformation of electron-poor alkenes for producing flavours and fragrances of industrial interest is discussed.

  2. New scenario of the non-conventional renewable energies on Chile after the incentives created on the ''Short Law I''

    Energy Technology Data Exchange (ETDEWEB)

    Leonardo, Valencia M. [Facultad de Ciencias y Tecnologia, Universidad Adolfo Ibanez Av. Diagonal Las Torres 2640, Penalolen, Santiago (Chile)

    2008-06-15

    Non-conventional renewable energies have never played an important role in the Chilean energy generation system, mainly due to the economic barriers that actually exists on our country for the inclusion of these kinds of technologies. Nevertheless, the use of renewable energy system technologies have started to be an interesting issue for the Chilean government, and for that reason, the last modification of the Energy Law during 2004, usually known as ''Short Law I'', introduced the first direct incentive to renewable energy generation (specifically in the art. 71-7). In this work we analyze in detail the modification on the electric law we mentioned before, especially for geothermal and wind power generation, and we compare the economic incentive generated with the new law and the differences between the real energy costs using renewable energy systems technologies and the current energy price in Chile. It is clear from the analysis that the total incentives do not cover more than 8.3% of the price differences between incomes and costs. (author)

  3. Relativistic Gravothermal Instabilities

    CERN Document Server

    Roupas, Zacharias

    2014-01-01

    The thermodynamic instabilities of the self-gravitating, classical ideal gas are studied in the case of static, spherically symmetric configurations in General Relativity taking into account the Tolman-Ehrenfest effect. One type of instabilities is found at low energies, where thermal energy becomes too weak to halt gravity and another at high energies, where gravitational attraction of thermal pressure overcomes its stabilizing effect. These turning points of stability are found to depend on the total rest mass $\\mathcal{M}$ over the radius $R$. The low energy instability is the relativistic generalization of Antonov instability, which is recovered in the limit $G\\mathcal{M} \\ll R c^2$ and low temperatures, while in the same limit and high temperatures, the high energy instability recovers the instability of the radiation equation of state. In the temperature versus energy diagram of series of equilibria, the two types of gravothermal instabilities make themselves evident as a double spiral! The two energy l...

  4. Shoulder instability; Schulterinstabilitaeten

    Energy Technology Data Exchange (ETDEWEB)

    Kreitner, Karl-Friedrich [Mainiz Univ. (Germany). Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie

    2014-06-15

    In the shoulder, the advantages of range of motion are traded for the disadvantages of vulnerability to injury and the development of instability. Shoulder instability and the lesion it produces represent one of the main causes of shoulder discomfort and pain. Shoulder instability is defined as a symptomatic abnormal motion of the humeral head relative to the glenoid during active shoulder motion. Glenohumeral instabilities are classified according to their causative factors as the pathogenesis of instability plays an important role with respect to treatment options: instabilities are classified in traumatic and atraumatic instabilities as part of a multidirectional instability syndrome, and in microtraumatic instabilities. Plain radiographs ('trauma series') are performed to document shoulder dislocation and its successful reposition. Direct MR arthrography is the most important imaging modality for delineation the different injury patterns on the labral-ligamentous complex and bony structures. Monocontrast CT-arthrography with use of multidetector CT scanners may be an alternative imaging modality, however, regarding the younger patient age, MR imaging should be preferred in the diagnostic work-up of shoulder instabilities. (orig.)

  5. [Historical consideration of the widespread infection of the hepatitis C virus in Japan and use of a fishbone diagram to investigate the cause].

    Science.gov (United States)

    Haga, Haruko; Fukushima, Noriko

    2011-01-01

    About 75% of Japanese liver cancer is caused by hepatitis C. Widespread infection of the virus resulted from inadequate medical knowledge, as well as the political, economic and administrative conditions of the time. We investigated the association between the widespread infection of the hepatitis C virus and the historical events. We used a fishbone diagram to investigate the cause of widespread infection of the hepatitis C virus and considered the issue from a historical standpoint. We found causes including treatment (medical care), transfusion (medicine), economy (expense) and people (infection route). These causes are explained in further detail below. 1) Treatment (medical care). The initial large-scale infection occurred following attempts to eradicate Schistosoma japonicum involving mass vaccination in schools and public health centers. 2) Transfusion (medicine). The use of non-heated fibrinogen for massive postpartum hemorrhage spread the virus further. In 1987, it resulted in a mass outbreak of hepatitis in Aomori Prefecture. 3) Economy (expense). Recognition of the benefit of disposable syringes was delayed. As a result, disposable syringes were too expensive to be widely available, and did not become low-priced. 4) People (infection route). The second wave of dissemination of the hepatitis C virus was stimulant abuse after World War II. Prior to the discovery of the hepatitis C virus, transmission resulted from repeated use of contaminated syringes. Although we initially thought that these four causes occurred independently on a historical chronology, associations between the causes were found when we investigated the problem with a fishbone diagram.

  6. Half-Sandwich Alkyl, Amido, and Iodo Samarium(II) Complexes: Non-Conventional Sterically Governed Oxidation of (tBu4 Carb)2 Sm.

    Science.gov (United States)

    Selikhov, Alexander N; Mahrova, Tatyana V; Cherkasov, Anton V; Fukin, Georgy K; Maron, Laurent; Trifonov, Alexander A

    2017-01-26

    The half-sandwich tetra-tert-butylcarbazol-9-yl iodo complex [(tBu4 Carb)Sm(μ-I)(THF)2 ]2 (1) was synthesized by the salt metathesis reaction of tBu4 CarbK and SmI2 (THF)2 in THF. Complex 1 along with metallic Cu was also isolated from the oxidation reaction of (tBu4 Carb)2 Sm by CuI. The formation of stable radical tBu4 Carb(.) was detected in this non-conventional process, indicating preferential oxidation of anion tBu4 Carb(-) vs. Sm(II) . The treatment of 1 with two equivalents of dibenzo-18-crown-6 resulted in heterolytic dissociation of a η(5) -bond Sm-tBu4 Carb and afforded an ionic compound [tBu4 carb(-) ][SmI(crown)(THF)2 ](+) (4). Alkylation of 1 with o-NMe2 C6 H4 CH2 K (1:2 molar ratio) in THF allowed for the synthesis of half-sandwich Sm(II) alkyl complex (tBu4 Carb)SmCH2 (o-NMe2 C6 H4 CH2 )(THF)2 (5) in 55 % yield. The amido complex (tBu4 Carb)SmN(SiMe3 )2 (DME) (6) was obtained by the reaction of 1 with two molar equivalents of NaN(SiMe3 )2 in THF in 89 % yield. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Non-conventional sources in energy. Solar, wind and biomass technologies. Decentralized generation of energy (SHPPs). 3. ed.; Fontes nao-convencionais de energia. As tecnologias solar, eolica e de biomassa. Geracao descentralizada (PCHs)

    Energy Technology Data Exchange (ETDEWEB)

    Montenegro, Alexandre de Albuquerque

    2000-07-01

    This work presents the papers submitted to the seminar on energy non-conventional sources, specifically the solar, wind and biomass technologies, held on the year of 1998, at the LABSOLAR/NCTS - Federal University of Santa Catarina, Florianopolis, SC, Brazil.

  8. Cavitation Instabilities in Inducers

    Science.gov (United States)

    2006-11-01

    gas handling turbomachines . The fluctuation of the cavity length is plotted in Fig.8 under the surge mode oscillation vi . The major differences...Cavitation Instabilities of Turbomachines .” AIAA Journal of Propulsion and Power, Vol.17, No.3, 636-643. [5] Tsujimoto, Y., (2006), “Flow Instabilities in

  9. Instability in evolutionary games.

    Directory of Open Access Journals (Sweden)

    Zimo Yang

    Full Text Available BACKGROUND: Phenomena of instability are widely observed in many dissimilar systems, with punctuated equilibrium in biological evolution and economic crises being noticeable examples. Recent studies suggested that such instabilities, quantified by the abrupt changes of the composition of individuals, could result within the framework of a collection of individuals interacting through the prisoner's dilemma and incorporating three mechanisms: (i imitation and mutation, (ii preferred selection on successful individuals, and (iii networking effects. METHODOLOGY/PRINCIPAL FINDINGS: We study the importance of each mechanism using simplified models. The models are studied numerically and analytically via rate equations and mean-field approximation. It is shown that imitation and mutation alone can lead to the instability on the number of cooperators, and preferred selection modifies the instability in an asymmetric way. The co-evolution of network topology and game dynamics is not necessary to the occurrence of instability and the network topology is found to have almost no impact on instability if new links are added in a global manner. The results are valid in both the contexts of the snowdrift game and prisoner's dilemma. CONCLUSIONS/SIGNIFICANCE: The imitation and mutation mechanism, which gives a heterogeneous rate of change in the system's composition, is the dominating reason of the instability on the number of cooperators. The effects of payoffs and network topology are relatively insignificant. Our work refines the understanding on the driving forces of system instability.

  10. Treatment of hip instability.

    Science.gov (United States)

    Robbins, G M; Masri, B A; Garbuz, D S; Greidanus, N; Duncan, C P

    2001-10-01

    Instability after total hip arthroplasty is a major source of patient morbidity, second only to aseptic loosening. Certain patient groups have been identified as having a greater risk of instability, including patients undergoing revision arthroplasty as early or late treatment for proximal femoral fractures.

  11. Nonlinear helical MHD instability

    Energy Technology Data Exchange (ETDEWEB)

    Zueva, N.M.; Solov' ev, L.S.

    1977-07-01

    An examination is made of the boundary problem on the development of MHD instability in a toroidal plasma. Two types of local helical instability are noted - Alfven and thermal, and the corresponding criteria of instability are cited. An evaluation is made of the maximum attainable kinetic energy, limited by the degree to which the law of conservation is fulfilled. An examination is made of a precise solution to a kinematic problem on the helical evolution of a cylindrical magnetic configuration at a given velocity distribution in a plasma. A numerical computation of the development of MHD instability in a plasma cylinder by a computerized solution of MHD equations is made where the process's helical symmetry is conserved. The development of instability is of a resonance nature. The instability involves the entire cross section of the plasma and leads to an inside-out reversal of the magnetic surfaces when there is a maximum unstable equilibrium configuration in the nonlinear stage. The examined instability in the tore is apparently stabilized by a magnetic hole when certain limitations are placed on the distribution of flows in the plasma. 29 references, 8 figures.

  12. Composição e estabilidade lipídica da farinha de espinhaço de tilapia Composition and lipid stability of tilapia fishbone flour

    Directory of Open Access Journals (Sweden)

    Maria Eugênia Petenuci

    2010-10-01

    Full Text Available Espinhaços de tilápias (Oreochromis niloticus são partes do peixe de composição desconhecida. A composição lipídica dos espinhaços não é citada na literatura, bem como a estabilidade da farinha do espinhaço durante o armazenamento. Nesse sentido, realizou se estudo de processamento dos espinhaços envolvendo etapas de cocção, trituração, secagem, peneiramento e armazenamento da farinha. A farinha ficou armazenada sob refrigeração por um período de 90 dias, sendo sua qualidade monitorada por meio da composição em ácidos graxos, índice de acidez e análises microbiológicas. Os resultados da composição centesimal foram de 14,2% (umidade, 40,8% (proteína, 18,3% (resíduo mineral fixo e 25,3% de lipídios totais. Nos lipídios totais foi identificado um total de 24 ácidos graxos, com predominância dos ácidos graxos (porcentagem média de 27.4% (ácido palmítico, 16:0, 35,15% (ácido oléico, 18:1n-9 e 11,82% (ácido linoléico, 18:2n-6 e, em menor proporção: 0,88% (ácido alfa-linolênico, 18:3n-3, 0,08% (ácido eicosapentaenóico, 20:5n-3 e 0,59 (ácido docosahexaenóico, 22:6n-3. Durante os 90 dias de armazenamento, foram observadas algumas alterações no índice de acidez e composição de alguns ácidos graxos, no entanto, para 60 dias de armazenamento, não foram observadas alterações na composição de nenhum ácido graxo, do índice de acidez e nas análises microbiológicas.The composition of the tilapia (Oreochromis niloticus fishbone is unknown. Lipid composition fishbone is not cited in the literature, and neither is the stability of the flour of the fishbone during storage. We studied the processing of fishbone cooking, grinding, drying, sieving and the storage of the flour. The flour was stored in a refrigerator for a period of 90 days, and its quality was monitored through fatty acid composition, acid index and microbiology control. The results of the proximate composition were of 14.2% (moisture, 40

  13. Spondylolisthesis and Posterior Instability

    Energy Technology Data Exchange (ETDEWEB)

    Niggemann, P.; Beyer, H.K.; Frey, H.; Grosskurth, D. (Privatpraxis fuer Upright MRT, Koeln (Germany)); Simons, P.; Kuchta, J. (Media Park Klinik, Koeln (Germany))

    2009-04-15

    We present the case of a patient with a spondylolisthesis of L5 on S1 due to spondylolysis at the level L5/S1. The vertebral slip was fixed and no anterior instability was found. Using functional magnetic resonance imaging (MRI) in an upright MRI scanner, posterior instability at the level of the spondylolytic defect of L5 was demonstrated. A structure, probably the hypertrophic ligament flava, arising from the spondylolytic defect was displaced toward the L5 nerve root, and a bilateral contact of the displaced structure with the L5 nerve root was shown in extension of the spine. To our knowledge, this is the first case described of posterior instability in patients with spondylolisthesis. The clinical implications of posterior instability are unknown; however, it is thought that this disorder is common and that it can only be diagnosed using upright MRI.

  14. Instabilities in nuclei

    CERN Document Server

    Csernai, László P; Papp, G

    1995-01-01

    The evolution of dynamical perturbations is examined in nuclear multifragmentation in the frame of Vlasov equation. Both plane wave and bubble type of perturbations are investigated in the presence of surface (Yukawa) forces. An energy condition is given for the allowed type of instabilities and the time scale of the exponential growth of the instabilities is calculated. The results are compared to the mechanical spinodal region predictions. PACS: 25.70 Mn

  15. Prediction of Algebraic Instabilities

    Science.gov (United States)

    Zaretzky, Paula; King, Kristina; Hill, Nicole; Keithley, Kimberlee; Barlow, Nathaniel; Weinstein, Steven; Cromer, Michael

    2016-11-01

    A widely unexplored type of hydrodynamic instability is examined - large-time algebraic growth. Such growth occurs on the threshold of (exponentially) neutral stability. A new methodology is provided for predicting the algebraic growth rate of an initial disturbance, when applied to the governing differential equation (or dispersion relation) describing wave propagation in dispersive media. Several types of algebraic instabilities are explored in the context of both linear and nonlinear waves.

  16. Propagating Instabilities in Solids

    Science.gov (United States)

    Kyriakides, Stelios

    1998-03-01

    Instability is one of the factors which limit the extent to which solids can be loaded or deformed and plays a pivotal role in the design of many structures. Such instabilities often result in localized deformation which precipitates catastrophic failure. Some materials have the capacity to recover their stiffness following a certain amount of localized deformation. This local recovery in stiffness arrests further local deformation and spreading of the instability to neighboring material becomes preferred. Under displacement controlled loading the propagation of the transition fronts can be achieved in a steady-state manner at a constant stress level known as the propagation stress. The stresses in the transition fronts joining the highly deformed zone to the intact material overcome the instability nucleation stresses and, as a result, the propagation stress is usually much lower than the stress required to nucleate the instability. The classical example of this class of material instabilities is L/"uders bands which tend to affect mild steels and other metals. Recent work has demonstrated that propagating instabilities occur in several other materials. Experimental and analytical results from four examples will be used to illustrate this point: First the evolution of L=FCders bands in mild steel strips will be revisited. The second example involves the evolution of stress induced phase transformations (austenite to martensite phases and the reverse) in a shape memory alloy under displacement controlled stretching. The third example is the crushing behavior of cellular materials such as honeycombs and foams made from metals and polymers. The fourth example involves the axial broadening/propagation of kink bands in aligned fiber/matrix composites under compression. The microstructure and, as a result, the micromechanisms governing the onset, localization, local arrest and propagation of instabilities in each of the four materials are vastly different. Despite this

  17. 运用鱼骨图分析非计划性拔管的原因及对策%Analysis of unplanned extubation reasons and countermeasures with fishbone diagram

    Institute of Scientific and Technical Information of China (English)

    李立伟; 刘文球; 董荔

    2016-01-01

    Objective:To analyze the reasons and countermeasures of unplanned extubation with fishbone diagram and lowerits incidence. Methods:Ana-lyzed reasons of the 25 unplanned extubation events happened in a third - grade class - A general hospital from January to December in 2014,and drew a fishbone diagram. Results:The fishbone diagram analysis showed that there were four aspects in reasons of unplanned extubation events,including people, object,method and environment,and that there were such countermeasures for reducing incidence of unplanned extubation as improving management, strengthening training and paying attention to propaganda and education. Conclusion:Using fishbone diagram can find out the root causes of unplanned ex-tubation and formulate effective measures.%目的:运用鱼骨图分析非计划性拔管的原因及对策,降低非计划性拔管的发生率。方法:分析某三级甲等综合医院2014年1~12月25例非计划性拔管事件的原因,绘制鱼骨图。结果:鱼骨图分析显示非计划性拔管的原因有人、物、法、环4个方面,降低非计划性拔管发生率的对策有改进管理、强化培训、重视宣教。结论:运用鱼骨图可以找到非计划性拔管的根本原因,制定有效措施。

  18. Neutrino beam plasma instability

    Indian Academy of Sciences (India)

    Vishnu M Bannur

    2001-10-01

    We derive relativistic fluid set of equations for neutrinos and electrons from relativistic Vlasov equations with Fermi weak interaction force. Using these fluid equations, we obtain a dispersion relation describing neutrino beam plasma instability, which is little different from normal dispersion relation of streaming instability. It contains new, nonelectromagnetic, neutrino-plasma (or electroweak) stable and unstable modes also. The growth of the instability is weak for the highly relativistic neutrino flux, but becomes stronger for weakly relativistic neutrino flux in the case of parameters appropriate to the early universe and supernova explosions. However, this mode is dominant only for the beam velocity greater than 0.25 and in the other limit electroweak unstable mode takes over.

  19. Causes of genome instability

    DEFF Research Database (Denmark)

    Langie, Sabine A S; Koppen, Gudrun; Desaulniers, Daniel

    2015-01-01

    , genome instability can be defined as an enhanced tendency for the genome to acquire mutations; ranging from changes to the nucleotide sequence to chromosomal gain, rearrangements or loss. This review raises the hypothesis that in addition to known human carcinogens, exposure to low dose of other...... scientists aware of the increasing need to unravel the underlying mechanisms via which chemicals at low doses can induce genome instability and thus promote carcinogenesis.......Genome instability is a prerequisite for the development of cancer. It occurs when genome maintenance systems fail to safeguard the genome's integrity, whether as a consequence of inherited defects or induced via exposure to environmental agents (chemicals, biological agents and radiation). Thus...

  20. Mixing through shear instabilities

    CERN Document Server

    Brüggen, M

    2000-01-01

    In this paper we present the results of numerical simulations of the Kelvin-Helmholtz instability in a stratified shear layer. This shear instability is believed to be responsible for extra mixing in differentially rotating stellar interiors and is the prime candidate to explain the abundance anomalies observed in many rotating stars. All mixing prescriptions currently in use are based on phenomenological and heuristic estimates whose validity is often unclear. Using three-dimensional numerical simulations, we study the mixing efficiency as a function of the Richardson number and compare our results with some semi-analytical formalisms of mixing.

  1. 鱼骨图法分析精神病患者出走的原因%Fishbone Diagram in Analyzing Eloping Reasons of Hospitalized Psychiatric Patients

    Institute of Scientific and Technical Information of China (English)

    徐国彬

    2011-01-01

    目的 分析精神病患者出走的原因,为防范精神病患者出走提供对策依据.方法 通过查看各病区上报的不良事件报告及原因、查阅病历等分析26例发生出走不良事件的精神病患者的相关资料,综合、分类后绘制鱼骨图.结果 精神病患者出走发生的原因可概括为管理因素、患者因素、工作人员因素和环境因素,防范对策包括加强出走高危患者的看护和病情观察、强化工作人员的风险防范意识、应用"五常法"做好病区安全管理及保证持续安全质量控制.结论 鱼骨图用于精神病患者出走原因的分析简便实用,为防范精神病患者出走提供了对策依据,为进一步实现持续安全质量改进提供了有力保证.%Objective To analyze the eloping reasons of hospitalized psychiatric patients so as to provide the basis for preventing the elopment of psychiatric patients. Methods A retrospective analysis was conducted on the relevant data through consulting the adverse event reports from different wards as well as eloping reason analysis and medical records to design a fishbone diagram. Results The eloping reasons included patients' condition, staff factors, environmental factors and management factors. Preventive measures included strengthening the nursing and observation of the disease of high-risk eloping patients,strengthening staff's awareness of risk prevention and applying five-elements method to ward management and ensure the continued safety and quality control. Conclusion Fishbone diagram is convenient in analyzing the eloping reasons of hospitalized psychiatric patients,which provides a basis for preventing eloping psychiatric patients and ensuring continued safety and quality control.

  2. 鱼骨图和流程图在开放性创伤手术感染管理中的应用%Application of fishbone diagram and flow chart in infection control for open trauma surgery

    Institute of Scientific and Technical Information of China (English)

    曹新平

    2013-01-01

    Objective To explore an infection control method for open trauma surgery using fishbone diagram and flow chart. Methods A fishbone diagram and a flow chart were drawn to identify the factors contributing to infection after open trauma surgery. Then 8 operating room nurses were were trained to use the fishbone diagram and the flow chart before the diagram and the chart were put into clinical practice. Results Before and after application of the fishbone diagram and the flow chart, nurses test scores in factors contributing to infection after open trauma surgery and infection control knowledge, rates of occupational exposures had significant differences(P<0. 01,P<0. 05) . The rate of accurate coping with an occupational exposure increased from 67. 31% to 100%. Conclusion Fishbone diagrams and flow charts which indentify the factors contributing to infection after open trauma surgery could effectively help nurses enhance the infection control quality of open trauma surgery, and decrease the incidence of occupational exposure.%目的 探讨鱼骨图和流程图在开放性创伤手术感染管理中的应用方法与效果.方法 制定开放性创伤手术感染因素鱼骨图和感染管理流程图,首先对手术室8名护士进行培训,然后将该图用于开放性创伤手术配合和管理中.结果 应用鱼骨图和流程图前后,护士开放性创伤手术易感因素和感染管理知识考核成绩、职业暴露率比较,差异有统计学意义(P<0.01,P<0.05);发生职业暴露后正确处理率由67.31%上升至100%.结论 应用开放性创伤手术感染因素鱼骨图和感染管理流程图,可以帮助护士有效提高开放性创伤手术的感染管理质量,降低职业暴露发生率.

  3. How Do Hydrodynamic Instabilities Affect 3D Transport in Geophysical Vortices?

    Science.gov (United States)

    Wang, P.; Ozgokmen, T. M.

    2014-12-01

    Understanding three-dimensional (3D) transport in ocean eddies is important for processes at a variety of scales, ranging from plankton production to climate variability. It is well known that geophysical vortices are subject to various hydrodynamic instabilities. Yet the influence of these instabilities on 3D material transport in vortex systems is not well investigated. Focusing on barotropic, inertial and 3D instabilities, we analyze these instabilities with normal-mode method, and reproduce their characteristics via highly-resolved numerical simulations using a spectral element Navier-Stokes solver. By comparing the simulation results of stable and unstable vortices, we investigate the joint impacts of instabilities on 3D transport through three major aspects: (i) energy transfer, (ii) overturning transport of the secondary circulation, and (iii) rates of vertical exchange and mixing. It is found that instabilities can enhance local nonlinear interactions and cause the kinetic energy wavenumber spectrum to have slopes between the conventional -5/3 and -3 at inertial ranges. The cascade of a new quantity is proposed to explain these non-conventional slopes. One of our main results is the discovery of material exchange between the central vortex and satellite vortices through 3D pathways, called funnels. These funnels modify the concept of elliptic regions that can trap material when confined to 2D dynamics. Thus, we show that a family of vortices, created by the hydrodynamic instabilities of the initially unstable vortex, can still continue to operate in unity in order to complete the 3D transport in these systems. We also show that flow instabilities can double the magnitude of vertical velocity, increase the rate of vertical exchange by an order of magnitude and enhance mixing rate more than 100%.

  4. Comparative evaluation of the anti-diabetic activity of Pterocarpus marsupium Roxb. heartwood in alloxan induced diabetic rats using extracts obtained by optimized conventional and non conventional extraction methods.

    Science.gov (United States)

    Devgan, Manish; Nanda, Arun; Ansari, Shahid Husain

    2013-09-01

    The aim of the present study was to assess the anti-diabetic activity of Pterocarpus marsupium Roxb. heartwood in alloxan induced diabetic rats using extracts obtained by optimized conventional and non conventional extraction methods. Aqueous and ethanol extracts of Pterocarpus marsupium heartwood were prepared by conventional methods (infusion, decoction, maceration and percolation) and non conventional methods, such as ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE). The crude aqueous extracts were administered orally to both normal and alloxan induced male albino rats (Sprague-Dawley strain). The experimental set up consisted of 48 male albino rats divided into 6 groups: Normal control, diabetic control (sterile normal saline, 1 ml/100 g body weight), standard (gliclazide, 25 mg/1000g of body weight), groups 4-6 (crude aqueous percolation, optimized UAE and MAE extract, 250 mg/1000g of body weight). In acute treatment, the reduction of blood glucose level was statistically significant with the oral administration of UAE and percolation aqueous extracts to the hyperglycemic rats. In sub-acute treatment, the UAE aqueous extract led to consistent and statistically significant (p<0.001) reduction in the blood glucose levels. There was no abnormal change in body weight of the hyperglycemic animals after 10 days of administration of plant extracts and gliclazide. This study justifies the traditional claim and provides a rationale for the use of Pterocarpus marsupium to treat diabetes mellitus. The antidiabetic activity of Pterocarpus marsupium can be enhanced by extracting the heartwood by non conventional method of UAE.

  5. 高压脉冲电场对鱼骨液物理状态变化的影响%Effect of high intensity pulsed electric fields on physical changes of fishbone liquid

    Institute of Scientific and Technical Information of China (English)

    赫桂丹; 殷涌光; 闫晓侠; 于庆宇

    2015-01-01

    High-intensity pulsed electric field (PEF) is characterized by transfer uniformity, nonthermal performance, high efficiency, short processing time and low component pollution. PEF shows unique advantages in the processing of liquid foods and thus can be widely applied to sterilization, extraction and enzyme inactivation of foods. PEF is a key processing technique that is most promising for industrial application in the past decade. Nevertheless, the effects of PEF on the physical state changes of foods have never been reported. With the rapid development of fishery worldwide, the fishbone from the majority of fish products is treated as tailing, which is restricted by low price, low processing capacity, low technical content, few high-value-added products, and low level of comprehensive processing and utilization. Higher requirements have been raised for the effective utilization of fish resources along with the development of modern food science and technology, especially the aquatic product processing industry. In this study, a texture analyzer was used to clarify the rheological properties of fishbone liquid and investigate the effects of PEF on the physical state changes of fishbone liquid. The indices used included the first and second compression work, elasticity, cohesiveness and gumminess. The principal component analysis was used to comprehensively assess the physical states of fishbone liquid. This analytical process was simplified into a comprehensive index equation. Single-factor tests were used to clarify the effects of PEF parameters on the physical state changes. The Box-Behnken design and response surface methodology (RSM) were used to investigate the effects of PEF on the electric field intensity, pulse number, and liquid-material ratio of fishbone liquid. Taking comprehensive index as the response value, we finished a 3-factor 3-level central composite design and acquired the optimal parameters of PEF:liquid-material ratio was 9.81 mL/g, field

  6. Physicochemical properties and composition of pignut (Jatropha curcas) non-conventional oil from different regions of Benin; Proprietes physico-chimiques et composition de l'huile non conventionnelle de pourghere (Jatropha curcas) de differentes regions du Benin

    Energy Technology Data Exchange (ETDEWEB)

    Dossou Sika Salome, Kpoviessi; Accrombessi, G.C.; Kossouoh, C. [Universite d' Abomey-Calavi, Lab. de Chimie Organique, Faculte des Sciences et Technique, Cotonou (Benin); Soumanou, M.M. [Universite d' Abomey-Calavi, Lab. de Recherche en Chimie et Biologie Appliquees, College Polytechnique Universitaire, Cotonou (Benin); Moudachirou, M. [Universite d' Abomey-Calavi, Lab. de Pharmacognosie et des Huiles Essentielles(FSS/FAST/UAC), (Benin)

    2004-11-01

    The non-conventional oils extracted from pignut seeds in eight localities of Benin have been studied. Oil content of seeds was in the range of 40 to 60%. Oil samples of different localities showed liquid and unsaturated oils and contained mainly oleic acid (43 to 53%), linoleic acid (20 to 32%) and palmitic acid (13 to 15%). Un-saponifiable content of these samples did not exceed 4%, except at Bohicon (5,5%) and Akiza (8,4%). These oils are used in the formulation of biofuels for the energy production. (authors)

  7. A Comparative Study Between the Early Stages Hydration of a High Strength and Sulphate Resistant Portland Cement and the Type II F Portland Cement Through Non Conventional Differential Thermal Analysis and Thermogravimetry

    OpenAIRE

    Neves Junior,Alex; Viana,Marcelo Mendes; Dweck,Jo; Toledo Filho,Romildo Dias

    2015-01-01

    This work presents a study, which compares the early stages of hydration of a High Initial Strength and Sulphate Resistant Portland Cement (HIS SR PC) with those of Type II F Portland Cement (PC II), by Non-Conventional Differential Thermal Analysis (NCDTA) within the first 24 hours of hydration. Water/cement (w/c) ratios equal to 0.5, 0.6 and 0.66 were used to prepare the pastes. The hydration of these two types of cement was monitored on real time by NCDTA curves, through the thermal effect...

  8. Shock instability in dissipative gases

    OpenAIRE

    Radulescu, Matei I.; Sirmas, Nick

    2011-01-01

    Previous experiments have revealed that shock waves in thermally relaxing gases, such as ionizing, dissociating and vibrationally excited gases, can become unstable. To date, the mechanism controlling this instability has not been resolved. Previous accounts of the D'yakov-Kontorovich instability, and Bethe-Zel'dovich-Thompson behaviour could not predict the experimentally observed instability. To address the mechanism controlling the instability, we study the propagation of shock waves in a ...

  9. Application of Fishbone Diagram in Risk Control of Pyrogen Reaction%鱼骨图在致热源反应风险控制中的应用

    Institute of Scientific and Technical Information of China (English)

    蒋忠伟; 吴凤莲; 王秦; 许平娟

    2014-01-01

    This paper mainly expounds the application of fishbone diagram analysis method in the prevention of complications caused by dialysis equipment applications, and puts forward to the potential risks, which could cause pyrogen reaction to the patients, such as risks in the maintenance of water treatment system, disinfection of the reverse osmosis membrane, disinfection of the ward pipeline, the use of dialysate, disinfection of the dialysis machine. Corresponding prevention measures are also introduced in this paper.%本文主要阐述了鱼骨图分析法在预防透析设备所致并发症的应用。以致热源反应为例,提出了水处理系统预处理的维护,反渗膜的消毒,病房管道的消毒,透析液的使用,透析机的消毒,透析耗材的使用等环节中可能引发患者致热源反应存在的风险,并陈述了预防的措施。

  10. Using a Six Sigma Fishbone Analysis Approach To Evaluate the Effect of Extreme Weather Events on Salmonella Positives in Young Chicken Slaughter Establishments.

    Science.gov (United States)

    Linville, John W; Schumann, Douglas; Aston, Christopher; Defibaugh-Chavez, Stephanie; Seebohm, Scott; Touhey, Lucy

    2016-12-01

    A six sigma fishbone analysis approach was used to develop a machine learning model in SAS, Version 9.4, by using stepwise linear regression. The model evaluated the effect of a wide variety of variables, including slaughter establishment operational measures, normal (30-year average) weather, and extreme weather events on the rate of Salmonella -positive carcasses in young chicken slaughter establishments. Food Safety and Inspection Service (FSIS) verification carcass sampling data, as well as corresponding data from the National Oceanographic and Atmospheric Administration and the Federal Emergency Management Agency, from September 2011 through April 2015, were included in the model. The results of the modeling show that in addition to basic establishment operations, normal weather patterns, differences from normal and disaster events, including time lag weather and disaster variables, played a role in explaining the Salmonella percent positive that varied by slaughter volume quartile. Findings show that weather and disaster events should be considered as explanatory variables when assessing pathogen-related prevalence analysis or research and slaughter operational controls. The apparent significance of time lag weather variables suggested that at least some of the impact on Salmonella rates occurred after the weather events, which may offer opportunities for FSIS or the poultry industry to implement interventions to mitigate those effects.

  11. Uso de terapias não convencionais no manejo da crise aguda de asma refratária Non-conventional therapies to manage refractory acute asthma attack

    Directory of Open Access Journals (Sweden)

    RAQUEL HERMES ROSA OLIVEIRA

    2002-09-01

    Full Text Available Uma paciente em crise aguda de asma, refratária ao uso de beta2-agonista inalatório e intravenoso, aminofilina intravenosa e corticóide, em ventilação mecânica, foi tratada com métodos terapêuticos não convencionais: broncoscopia, lavado broncoalveolar com N-acetilcisteína e ventilação com halotano. Houve melhora dos parâmetros ventilatórios após o lavado e a resolução do broncoespasmo ocorreu após a anestesia, propiciando a extubação e alta da UTI. É feita uma revisão da literatura sobre o uso desses métodos na crise aguda de asma.A patient with an acute asthma attack refractory to inhaled and intravenous beta2-agonist, aminophylline and corticosteroids was submitted to mechanical ventilation and treated with non-conventional therapies: bronchoscopy with bronchoalveolar lavage using N-acetylcysteine and halothane inhalation. The ventilatory parameters improved after lavage, however, bronchospasm resolution occurred only after anesthesia which was followed by extubation and discharge from the ICU. A review of the use of these non-conventional therapeutic modalities for the management of acute asthma attack is presented.

  12. Production of biomass, polysaccharides, and ganoderic acid using non-conventional carbon sources under submerged culture of the Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum (W.Curt.:Fr.)P. Karst. (higher Basidiomycetes).

    Science.gov (United States)

    Zapata, Paola; Rojas, Diego; Atehortúa, Lucía

    2012-01-01

    The effect of different non-conventional carbon sources was studied in the submerged culture of Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum, for simultaneous production of mycelial biomass, bioactive ganoderic acid, and polysaccharides, in less time, using non-conventional carbon sources to minimize the high costs of current culture media. The optimal medium composition was defined as (g/L): 50 of barley flour, 0.2 of KH2PO4, 0.1 of MgSO4ⁱ7H2O, and 1 NH4Cl. Cultivated under this complex culture medium, the mycelial biomass production was 23.49 ± 0.37 g/L; the extracellular polysaccharides production was 2.72 ± 0.11 g/L; the intracellular polysaccharides production was 2.22 ± 0.06 g/L; the ganoderic acids production was 299.67 ± 11.63 mg/L. One liter of culture medium developed in this project was priced at USD $ 0.11 if barley flour is used as carbon source or $ 0.13 with oat flour in order to get a good amount of products of interest.

  13. Cloning and extracellular expression of a raw starch digesting α-amylase (Blamy-I) and its application in bioethanol production from a non-conventional source of starch.

    Science.gov (United States)

    Roy, Jetendra K; Manhar, Ajay K; Nath, Dhrubajyoti; Mandal, Manabendra; Mukherjee, Ashis K

    2015-11-01

    The aim of this study was to clone and efficiently express a raw starch-digesting α-amylase enzyme in the culture media and also to investigate the potential application of this recombinant enzyme in the digestion of non-conventional raw starch for bioethanol production. A raw starch digesting α-amylase gene isolated from Bacillus licheniformis strain AS08E was cloned and extracellularly expressed in E. coli cells using the native signal peptide. The mature recombinant α-amylase (Blamy-I) consisting of 483 amino acid residues was found to be homogenous with a mass of 55.3 kDa (by SDS-PAGE analysis) and a predicted pI of 6.05. Structural and functional analysis of Blamy-I revealed the presence of an extra Ca(2+) -binding region between the A and C domains responsible for higher thermostability of this enzyme. The statistical optimization of E. coli culture conditions resulted in an approximately eightfold increase in extracellular expression of Blamy-I as compared to its production under non-optimized conditions. Blamy-I demonstrated optimum enzyme activity at 80 °C and pH 10.0, and efficiently hydrolyzed raw starch isolated from a non-conventional, underutilized jack fruit seeds. Further utilization of this starch for bioethanol production using Blamy-I and Saccharomyces cerevisiae also proved to be highly promising.

  14. Genetic instability in Gynecological Cancer

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qing-hua; ZHOU Hong-lin

    2003-01-01

    Defects of mismatch repair (MMR) genes also have beenidentified in many kinds of tumors. Loss of MMR functionhas been linked to genetic instability especially microsatelliteinstability that results in high mutation rate. In this review, wediscussed the microsatellite instability observed in thegynecological tumors. We also discussed defects in the DNAmismatch repair in these tumors and their correlation to themicrosatellite instability, as well as the gene mutations due tothe microsatellite instability in these tumors. From thesediscussion, we tried to understand the mechanism ofcarcinogenesis in gynecological tumors from the aspect ofgenetic instability due to mismatch repair defects.

  15. Instabilities in sensory processes

    Science.gov (United States)

    Balakrishnan, J.

    2014-07-01

    In any organism there are different kinds of sensory receptors for detecting the various, distinct stimuli through which its external environment may impinge upon it. These receptors convey these stimuli in different ways to an organism's information processing region enabling it to distinctly perceive the varied sensations and to respond to them. The behavior of cells and their response to stimuli may be captured through simple mathematical models employing regulatory feedback mechanisms. We argue that the sensory processes such as olfaction function optimally by operating in the close proximity of dynamical instabilities. In the case of coupled neurons, we point out that random disturbances and fluctuations can move their operating point close to certain dynamical instabilities triggering synchronous activity.

  16. Modulation instability: The beginning

    Science.gov (United States)

    Noskov, Roman; Belov, Pavel; Kivshar, Yuri

    2012-11-01

    The study of metal nanoparticles plays a central role in the emerging novel technologies employing optics beyond the diffraction limit. Combining strong surface plasmon resonances, high intrinsic nonlinearities and deeply subwavelength scales, arrays of metal nanoparticles offer a unique playground to develop novel concepts for light manipulation at the nanoscale. Here we suggest a novel principle to control localized optical energy in chains of nonlinear subwavelength metal nanoparticles based on the fundamental nonlinear phenomenon of modulation instability. In particular, we demonstrate that modulation instability can lead to the formation of long-lived standing and moving nonlinear localized modes of several distinct types such as bright and dark solitons, oscillons, and domain walls. We analyze the properties of these nonlinear localized modes and reveal different scenarios of their dynamics including transformation of one type of mode to another. We believe this work paves a way towards the development of nonlinear nanophotonics circuitry.

  17. Instability and internet design

    Directory of Open Access Journals (Sweden)

    Sandra Braman

    2016-09-01

    Full Text Available Instability - unpredictable but constant change in one’s environment and the means with which one deals with it - has replaced convergence as the focal problem for telecommunications policy in general and internet policy in particular. Those who designed what we now call the internet during the first decade of the effort (1969-1979, who in essence served simultaneously as its policy-makers, developed techniques for coping with instability of value for network designers today and for those involved with any kind of large-scale sociotechnical infrastructure. Analysis of the technical document series that was medium for and record of that design process reveals coping techniques that began with defining the problem and went on to include conceptual labour, social practices, and technical approaches.

  18. Gravitational instabilities of superspinars

    CERN Document Server

    Pani, Paolo; Berti, Emanuele; Cardoso, Vitor

    2010-01-01

    Superspinars are ultracompact objects whose mass M and angular momentum J violate the Kerr bound (cJ/GM^2>1). Recent studies analyzed the observable consequences of gravitational lensing and accretion around superspinars in astrophysical scenarios. In this paper we investigate the dynamical stability of superspinars to gravitational perturbations, considering either purely reflecting or perfectly absorbing boundary conditions at the "surface" of the superspinar. We find that these objects are unstable independently of the boundary conditions, and that the instability is strongest for relatively small values of the spin. Also, we give a physical interpretation of the various instabilities that we find. Our results (together with the well-known fact that accretion tends to spin superspinars down) imply that superspinars are very unlikely astrophysical alternatives to black holes.

  19. The instability of markets

    CERN Document Server

    Huberman, B A; Huberman, Bernardo A; Youssefmir, Michael

    1995-01-01

    Recent developments in the global liberalization of equity and currency markets, coupled to advances in trading technologies, are making markets increasingly interdependent. This increased fluidity raises questions about the stability of the international financial system. In this paper, we show that as couplings between stable markets grow, the likelihood of instabilities is increased, leading to a loss of general equilibrium as the system becomes increasingly large and diverse.

  20. Modulation instability: The beginning

    Science.gov (United States)

    Zakharov, V. E.; Ostrovsky, L. A.

    2009-03-01

    We discuss the early history of an important field of “sturm and drang” in modern theory of nonlinear waves. It is demonstrated how scientific demand resulted in independent and almost simultaneous publications by many different authors on modulation instability, a phenomenon resulting in a variety of nonlinear processes such as envelope solitons, envelope shocks, freak waves, etc. Examples from water wave hydrodynamics, electrodynamics, nonlinear optics, and convection theory are given.

  1. Carpal instability nondissociative.

    Science.gov (United States)

    Wolfe, Scott W; Garcia-Elias, Marc; Kitay, Alison

    2012-09-01

    Carpal instability nondissociative (CIND) represents a spectrum of conditions characterized by kinematic dysfunction of the proximal carpal row, often associated with a clinical "clunk." CIND is manifested at the midcarpal and/or radiocarpal joints, and it is distinguished from carpal instability dissociative (CID) by the lack of disruption between bones within the same carpal row. There are four major subcategories of CIND: palmar, dorsal, combined, and adaptive. In palmar CIND, instability occurs across the entire proximal carpal row. When nonsurgical management fails, surgical options include arthroscopic thermal capsulorrhaphy, soft-tissue reconstruction, or limited radiocarpal or intercarpal fusions. In dorsal CIND, the capitate subluxates dorsally from its reduced resting position. Dorsal CIND usually responds to nonsurgical management; refractory cases respond to palmar ligament reefing and/or dorsal intercarpal capsulodesis. Combined CIND demonstrates signs of both palmar and dorsal CIND and can be treated with soft-tissue or bony procedures. In adaptive CIND, the volar carpal ligaments are slackened and are less capable of inducing the physiologic shift of the proximal carpal row from flexion into extension as the wrist ulnarly deviates. Treatment of choice is a corrective osteotomy to restore the normal volar tilt of the distal radius.

  2. Chromosomal instability in meningiomas.

    Science.gov (United States)

    van Tilborg, Angela A G; Al Allak, Bushra; Velthuizen, Sandra C J M; de Vries, Annie; Kros, Johan M; Avezaat, Cees J J; de Klein, Annelies; Beverloo, H Berna; Zwarthoff, Ellen C

    2005-04-01

    Approximately 60% of sporadic meningiomas are caused by inactivation of the NF2 tumor suppressor gene on chromosome 22. No causative gene is known for the remaining 40%. Cytogenetic analysis shows that meningiomas caused by inactivation of the NF2 gene can be divided into tumors that show monosomy 22 as the sole abnormality and tumors with a more complex karyotype. Meningiomas not caused by the NF2 gene usually have a diploid karyotype. Here we report that, besides the clonal chromosomal aberrations, the chromosome numbers in many meningiomas varied from one metaphase spread to the other, a feature that is indicative of chromosomal instability. Unexpectedly and regardless of genotype, a subgroup of tumors was observed with an average number of 44.9 chromosomes and little variation in the number of chromosomes per metaphase spread. In addition, a second subgroup was recognized with a hyperdiploid number of chromosomes (average 48.5) and considerable variation in numbers per metaphase. However, this numerical instability resulted in a clonal karyotype with chromosomal gains and losses in addition to loss of chromosome 22 only in meningiomas caused by inactivation of the NF2 gene. In cultured cells of all tumor groups, bi- and multinucleated cells were seen, as well as anaphase bridges, residual chromatid strings, multiple spindle poles, and unseparated chromatids, suggesting defects in the mitotic apparatus or kinetochore. Thus, we conclude that even a benign and slow-growing tumor like a meningioma displays chromosomal instability.

  3. Shoulder instability; Schultergelenkinstabilitaet

    Energy Technology Data Exchange (ETDEWEB)

    Sailer, J.; Imhof, H. [Abteilung Osteoradiologie, Univ.-Klinik fuer Radiodiagnostik Wien (Austria)

    2004-06-01

    Shoulder instability is a common clinical feature leading to recurrent pain and limitated range of motion within the glenohumeral joint. Instability can be due a single traumatic event, general joint laxity or repeated episodes of microtrauma. Differentiation between traumatic and atraumatic forms of shoulder instability requires careful history and a systemic clinical examination. Shoulder laxity has to be differentiated from true instability followed by the clinical assessment of direction and degree of glenohumeral translation. Conventional radiography and CT are used for the diagnosis of bony lesions. MR imaging and MR arthrography help in the detection of soft tissue affection, especially of the glenoid labrum and the capsuloligamentous complex. The most common lesion involving the labrum is the anterior labral tear, associated with capsuloperiostal stripping (Bankart lesion). A number of variants of the Bankart lesion have been described, such as ALPSA, SLAP or HAGL lesions. The purpose of this review is to highlight different forms of shoulder instability and its associated radiological findings with a focus on MR imaging. (orig.) [German] Die Schultergelenkinstabilitaet ist haeufig fuer wiederholt auftretende Schmerzen sowie eine eingeschraenkte Beweglichkeit im Glenohumeralgelenk verantwortlich. Sie kann als Folge eines vorangegangenen Traumas, einer generellen Hyperlaxitaet oder infolge wiederholter Mikrotraumen entstehen. Die Differenzierung zwischen traumatischer und atraumatischer Form der Gelenkinstabilitaet erfordert eine sorgfaeltige Anamnese und eine genaue klinische Untersuchung. Die Gelelenklaxitaet als Differenzialdiagnose muss von der echten Instabilitaet unterschieden werden, die Instabilitaet wird dann im Rahmen des klinischen Status nach Grad und Richtung der glenohumeralen Translation unterteilt. Zur Diagnose knoecherner Laesionen werden das konventionelle Roentgen sowie die CT herangezogen. MRT sowie MR-Arthrographie dienen zur Detektion

  4. Energetic-particle-driven instabilities and induced fast-ion transport in a reversed field pinch

    Science.gov (United States)

    Lin, Liang

    2013-10-01

    Multiple bursty energetic-particle (EP) modes with fishbone-like structures are observed during 1 MW tangential neutral-beam injection into MST reversed field pinch (RFP) plasmas. The distinguishing features of the RFP, including large magnetic shear (tending to add stability) and weak toroidal magnetic field (leading to large fast ion beta and stronger drive), provide a complementary environment to tokamak and stellarator configurations for exploring basic understanding of these instabilities. Detailed measurements of the EP mode characteristics and temporal-spatial dynamics reveal their influence on fast ion transport and interaction with global tearing modes. Internal magnetic field fluctuations associated with the EP modes are directly observed for the first time by Faraday-effect polarimetry (frequency ~ 90 kHz and amplitude ~ 2 G). Simultaneously measured density fluctuations exhibit a dynamically evolving and asymmetric spatial structure that peaks near the core where fast ions reside and shifts outward as the instability evolves. Furthermore, the EP mode frequencies appear at ~k∥VA , consistent with continuum modes destabilized by strong drive. The fast-ion temporal dynamics, measured by a neutral particle analyzer, resemble a classical predator-prey relaxation oscillation. It contains a slow-growing phase arising from the beam fueling followed by a rapid drop (~ 15 %) when the EP modes peak, indicating the fluctuation-induced transport maintains a stiff fast-ion density profile. The inferred transport rate is strongly enhanced (× 2) with the onset of multiple nonlinearly-interacting EP modes. The fast ions also impact global tearing modes, reducing their amplitudes by up to 65%. This mode reduction is lessened following the EP-bursts, further evidence for fast ion redistribution that weakens the suppression mechanism. Possible tearing mode suppression mechanisms will be discussed. Work supported by US DoE.

  5. Radiation Induced Genomic Instability

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, William F.

    2011-03-01

    Radiation induced genomic instability can be observed in the progeny of irradiated cells multiple generations after irradiation of parental cells. The phenotype is well established both in vivo (Morgan 2003) and in vitro (Morgan 2003), and may be critical in radiation carcinogenesis (Little 2000, Huang et al. 2003). Instability can be induced by both the deposition of energy in irradiated cells as well as by signals transmitted by irradiated (targeted) cells to non-irradiated (non-targeted) cells (Kadhim et al. 1992, Lorimore et al. 1998). Thus both targeted and non-targeted cells can pass on the legacy of radiation to their progeny. However the radiation induced events and cellular processes that respond to both targeted and non-targeted radiation effects that lead to the unstable phenotype remain elusive. The cell system we have used to study radiation induced genomic instability utilizes human hamster GM10115 cells. These cells have a single copy of human chromosome 4 in a background of hamster chromosomes. Instability is evaluated in the clonal progeny of irradiated cells and a clone is considered unstable if it contains three or more metaphase sub-populations involving unique rearrangements of the human chromosome (Marder and Morgan 1993). Many of these unstable clones have been maintained in culture for many years and have been extensively characterized. As initially described by Clutton et al., (Clutton et al. 1996) many of our unstable clones exhibit persistently elevated levels of reactive oxygen species (Limoli et al. 2003), which appear to be due dysfunctional mitochondria (Kim et al. 2006, Kim et al. 2006). Interestingly, but perhaps not surprisingly, our unstable clones do not demonstrate a “mutator phenotype” (Limoli et al. 1997), but they do continue to rearrange their genomes for many years. The limiting factor with this system is the target – the human chromosome. While some clones demonstrate amplification of this chromosome and thus lend

  6. Comparison on extraction yield of sennoside A and sennoside B from senna (Cassia angustifolia) using conventional and non conventional extraction techniques and their quantification using a validated HPLC-PDA detection method.

    Science.gov (United States)

    Dhanani, Tushar; Singh, Raghuraj; Reddy, Nagaraja; Trivedi, A; Kumar, Satyanshu

    2017-05-01

    Senna is an important medicinal plant and is used in many Ayurvedic formulations. Dianthraquinone glucosides are the main bioactive phytochemicals present in leaves and pods of senna. The extraction efficiency in terms of yield and composition of the extract of senna prepared using both conventional (cold percolation at room temperature and refluxing) and non conventional (ultrasound and microwave assisted solvent extraction as well as supercritical fluid extraction) techniques were compared in the present study. Also a rapid reverse phase HPLC-PDA detection method was developed and validated for the simultaneous determination of sennoside A and sennoside B in the different extracts of senna leaves. Ultrasound and microwave assisted solvent extraction techniques were more effective in terms of yield and composition of the extracts compared to cold percolation at room temperature and refluxing methods of extraction.

  7. 鱼骨分析法在急诊分诊护理中的应用%EXPLORATORY STUDY ON EMERGENCY TRIAGE NURSING MANAGEMENT OF FISHBONE DIA-GRAM

    Institute of Scientific and Technical Information of China (English)

    周萍

    2015-01-01

    目的:探索鱼骨分析法在急诊分诊护理管理中应用的效果。方法将2013年1—6月作为实施鱼骨图分析方法前,将2013年7—12月作为鱼骨图分析方法后。实施鱼骨图分析方法前后分别收集300例患者进行护理服务质量分析,描述鱼骨图分析的实施过程及效果。结果实施鱼骨图分析方法后患者并发症发生率、病死率均明显下降,分诊准确率明显升高,差异有统计学意义(P <0.05);实施鱼骨图分析方法后患者满意度明显高于实施前,差异有统计学意义(P <0.01)。结论鱼骨图分析方法能明显提高急诊分诊护理服务质量水平,具有重要的临床价值,值得推广应用。%Objective To explore the effect of fishbone diagram of nursing management in emergency. Methods Three hundreds patients were selected as the subjects in January to June 2013 and in July to De-cember 2013 respectively,the former received a fishbone diagram nursing management,the latter with a general management,and then the quality of nursing service was analyzed.Results After fishbone diagram analysis,the complication rate and mortality rate decreased significantly,triage accuracy rate increased sig-nificantly than before,the differences were statistically significant (P <0.05);in addition,patients'satis-faction was also significantly higher than before with a statistically significant (P <0.01).Conclusion The fishbone diagram analysis method can obviously improve the emergency triage nursing service quality,and it is worthy of popularization and application with an important clinical value.

  8. Modulational instability of nematic phase

    Indian Academy of Sciences (India)

    T Mithun; K Porsezian

    2014-02-01

    We numerically observe the effect of homogeneous magnetic field on the modulationally stable case of polar phase in = 2 spinor Bose–Einstein condensates (BECs). Also we investigate the modulational instability of uniaxial and biaxial (BN) states of polar phase. Our observations show that the magnetic field triggers the modulational instability and demonstrate that irrespective of the magnetic field effect the uniaxial and biaxial nematic phases show modulational instability.

  9. Political Instability and Economic Growth

    OpenAIRE

    Swagel, Phillip; Roubini, Nouriel; Ozler, Sule; Alesina, Alberto

    1992-01-01

    This paper investigates the relationship between political instability and per capita GDP growth in a sample of 113 countries for the period 1950-1982. We define ?political instability? as the propensity of a government collapse, and we estimate a model in which political instability and economic growth are jointly determined. The main result of this paper is that in countries and time periods with a high propensity of government collapse, growth is significantly lower than otherwise. This ef...

  10. Weibel instability with nonextensive distribution

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Hui-Bin; Liu, Shi-Bing [Strong-field and Ultrafast Photonics Lab, Institute of Laser Engineering, Beijing University of Technology, Beijing 100124 (China)

    2013-10-15

    Weibel instability in plasma, where the ion distribution is isotropic and the electron component of the plasma possesses the anisotropic temperature distribution, is investigated based on the kinetic theory in context of nonextensive statistics mechanics. The instability growth rate is shown to be dependent on the nonextensive parameters of both electron and ion, and in the extensive limit, the result in Maxwellian distribution plasma is recovered. The instability growth rate is found to be enhanced as the nonextensive parameter of electron increases.

  11. Instabilities in mimetic matter perturbations

    Science.gov (United States)

    Firouzjahi, Hassan; Gorji, Mohammad Ali; Mansoori, Seyed Ali Hosseini

    2017-07-01

    We study cosmological perturbations in mimetic matter scenario with a general higher derivative function. We calculate the quadratic action and show that both the kinetic term and the gradient term have the wrong sings. We perform the analysis in both comoving and Newtonian gauges and confirm that the Hamiltonians and the associated instabilities are consistent with each other in both gauges. The existence of instabilities is independent of the specific form of higher derivative function which generates gradients for mimetic field perturbations. It is verified that the ghost instability in mimetic perturbations is not associated with the higher derivative instabilities such as the Ostrogradsky ghost.

  12. [Aspirin suppresses microsatellite instability].

    Science.gov (United States)

    Wallinger, S; Dietmaier, W; Beyser, K; Bocker, T; Hofstädter, F; Fishel, R; Rüschoff, J

    1999-01-01

    Nonsteroidal anti-inflammatory drugs (NSAIDs) exhibit cancer preventive effects and have been shown to induce regression of adenomas in FAP patients. In order to elucidate the probable underlying mechanism, the effect of NSAIDs on mismatch repair related microsatellite instability was investigated. Six colorectal cancer cell lines all but one deficient for human mismatch repair (MMR) genes were examined for microsatellite instability (MSI) prior and after treatment with Aspirin or Sulindac. For rapid in vitro analysis of MSI a microcloning assay was developed by combining Laser microdissection and random (PEP-) PCR prior to specific MSI-PCR. Effects of NSAIDs on cell cycle and apoptosis were systematically investigated by using flow cytometry and cell-sorting. MSI frequency in cells deficient of MMR genes (hMSH2, hMLH1, hMSH6) was markedly reduced after long-term (> 10 weeks) NSAID treatment. This effect was reversible, time- and concentration dependent. However, in the hPMS2 deficient endometrial cancer cell line (HEC-1-A) the MSI phenotype kept unchanged. According to cell sorting, non-apoptotic cells were stable and apoptotic cells were unstable. These results suggest that aspirin/sulindac induces a genetic selection for microsatellite stability in a subset of MMR-deficient cells and may thus provide an effective prophylactic therapy for HNPCC related colorectal carcinomas.

  13. Instability of enclosed horizons

    CERN Document Server

    Kay, Bernard S

    2013-01-01

    We study the classical massless scalar wave equation on the region of 1+1-dimensional Minkowski space between the two branches of the hyperbola $x^2-t^2=1$ with vanishing boundary conditions on it. We point out that there are initially finite-energy initially, say, right-going waves for which the stress-energy tensor becomes singular on the null-line $t+x=0$. We also construct the quantum theory of this system and show that, while there is a regular Hartle-Hawking-Israel-like state, there are coherent states built on this for which there is a similar singularity in the expectation value of the renormalized stress-energy tensor. We conjecture that in 1+3-dimensional situations with 'enclosed horizons' such as a (maximally extended) Schwarzschild black hole in equilibrium in a stationary box or the (maximally extended) Schwarzschild-AdS spacetime, there will be a similar singularity at the horizon and that would signal an instability when matter perturbations and/or gravity are switched on. Such an instability ...

  14. Libration driven multipolar instabilities

    CERN Document Server

    Cébron, David; Herreman, Wietze

    2014-01-01

    We consider rotating flows in non-axisymmetric enclosures that are driven by libration, i.e. by a small periodic modulation of the rotation rate. Thanks to its simplicity, this model is relevant to various contexts, from industrial containers (with small oscillations of the rotation rate) to fluid layers of terrestial planets (with length-of-day variations). Assuming a multipolar $n$-fold boundary deformation, we first obtain the two-dimensional basic flow. We then perform a short-wavelength local stability analysis of the basic flow, showing that an instability may occur in three dimensions. We christen it the Libration Driven Multipolar Instability (LDMI). The growth rates of the LDMI are computed by a Floquet analysis in a systematic way, and compared to analytical expressions obtained by perturbation methods. We then focus on the simplest geometry allowing the LDMI, a librating deformed cylinder. To take into account viscous and confinement effects, we perform a global stability analysis, which shows that...

  15. Non-Conventional Treatment Approaches in Pemphigus

    Directory of Open Access Journals (Sweden)

    Mutlu Çayırlı

    2013-09-01

    Full Text Available Pemphigus is a bullous auto-immune disease which has high mortality and morbidity rates and affects the skin and mucosa. Corticosteroids are still the baseline treatment modality of pemphigus management. However, non-steroidal drugs and methods have been used more frequently in patients with pemphigus who are non-responders to conventional therapy or have severe side effects. In this article we aimed to review unconventional therapy modalities in patients with pemphigus.

  16. Genetics of non-conventional lipoprotein fractions

    Science.gov (United States)

    Lipoprotein subclass measures associate with cardiometabolic disease risk. Currently the information that lipoproteins convey on disease risk over that of traditional demographic and lipid measures is minimal, and so their use is clinics is limited. However, lipoprotein subclass perturbations repres...

  17. Bony instability of the shoulder.

    Science.gov (United States)

    Bushnell, Brandon D; Creighton, R Alexander; Herring, Marion M

    2008-09-01

    Instability of the shoulder is a common problem treated by many orthopaedists. Instability can result from baseline intrinsic ligamentous laxity or a traumatic event-often a dislocation that injures the stabilizing structures of the glenohumeral joint. Many cases involve soft-tissue injury only and can be treated successfully with repair of the labrum and ligamentous tissues. Both open and arthroscopic approaches have been well described, with recent studies of arthroscopic soft-tissue techniques reporting results equal to those of the more traditional open techniques. Over the last decade, attention has focused on the concept of instability of the shoulder mediated by bony pathology such as a large bony Bankart lesion or an engaging Hill-Sachs lesion. Recent literature has identified unrecognized large bony lesions as a primary cause of failure of arthroscopic reconstruction for instability, a major cause of recurrent instability, and a difficult diagnosis to make. Thus, although such bony lesions may be relatively rare compared with soft-tissue pathology, they constitute a critically important entity in the management of shoulder instability. Smaller bony lesions may be amenable to arthroscopic treatment, but larger lesions often require open surgery to prevent recurrent instability. This article reviews recent developments in the diagnosis and treatment of bony instability.

  18. Cinerama sickness and postural instability

    NARCIS (Netherlands)

    Bos, J.E.; Ledegang, W.D.; Lubeck, A.J.A.; Stins, J.F.

    2013-01-01

    Motion sickness symptoms and increased postural instability induced by motion pictures have been reported in a laboratory, but not in a real cinema. We, therefore, carried out an observational study recording sickness severity and postural instability in 19 subjects before, immediately and 45 min af

  19. Marital instability after midlife.

    Science.gov (United States)

    Wu, Z; Penning, M J

    1997-09-01

    "Divorce in later life has been shown to produce dramatic declines in the economic, psychological, and physical well-being of marital partners. This study examines the prevalence and determinants of marital disruption after midlife using Becker's theory of marital instability. Using recent Canadian national data, the marital outcomes of women and men who were married as of age 40 are tracked across the remaining years of the marriage. Cox proportional hazard regression models indicate stabilizing effects of the duration of the marriage, the age at first marriage, the presence of young children, as well as of remarriage for middle-aged and older persons. Other significant risk factors include education, heterogamous marital status, premarital cohabitation, number of siblings, and region."

  20. Instability and Information

    CERN Document Server

    Patzelt, Felix

    2015-01-01

    Many complex systems exhibit extreme events far more often than expected for a normal distribution. This work examines how self-similar bursts of activity across several orders of magnitude can emerge from first principles in systems that adapt to information. Surprising connections are found between two apparently unrelated research topics: hand-eye coordination in balancing tasks and speculative trading in financial markets. Seemingly paradoxically, locally minimising fluctuations can increase a dynamical system's sensitivity to unpredictable perturbations and thereby facilitate global catastrophes. This general principle is studied in several domain-specific models and in behavioural experiments. It explains many findings in both fields and resolves an apparent antinomy: the coexistence of stabilising control or market efficiency and perpetual instabilities resembling critical phenomena in physical systems.

  1. Structural and Material Instability

    DEFF Research Database (Denmark)

    Cifuentes, Gustavo Cifuentes

    This work is a small contribution to the general problem of structural and material instability. In this work, the main subject is the analysis of cracking and failure of structural elements made from quasi-brittle materials like concrete. The analysis is made using the finite element method. Three...... use of interface elements) is used successfully to model cases where the path of the discontinuity is known in advance, as is the case of the analysis of pull-out of fibers embedded in a concrete matrix. This method is applied to the case of non-straight fibers and fibers with forces that have....... Numerical problems associated with the use of elements with embedded cracks based on the extended finite element method are presented in the next part of this work. And an alternative procedure is used in order to successfully remove these numerical problems. In the final part of this work, a computer...

  2. The bar instability revisited

    CERN Document Server

    Chiodi, Filippo; Claudin, Philippe

    2012-01-01

    The river bar instability is revisited, using a hydrodynamical model based on Reynolds averaged Navier-Stokes equations. The results are contrasted with the standard analysis based on shallow water Saint-Venant equations. We first show that the stability of both transverse modes (ripples) and of small wavelength inclined modes (bars) predicted by the Saint-Venant approach are artefacts of this hydrodynamical approximation. When using a more reliable hydrodynamical model, the dispersion relation does not present any maximum of the growth rate when the sediment transport is assumed to be locally saturated. The analysis therefore reveals the fundamental importance of the relaxation of sediment transport towards equilibrium as it it is responsible for the stabilisation of small wavelength modes. This dynamical mechanism is characterised by the saturation number, defined as the ratio of the saturation length to the water depth Lsat/H. This dimensionless number controls the transition from ripples (transverse patte...

  3. Beam instability Workshop - plenary sessions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The purpose of this workshop was to provide a review of the mechanisms of limiting beam instabilities, their cures, including feedback, and beam measurement for synchrotron radiation light sources. 12 plenary sessions took place whose titles are: 1) challenging brilliance and lifetime issues with increasing currents; 2) limiting instabilities in multibunch; 3) experience from high currents in B factories; 4) longitudinal dynamics in high intensity/bunch; 5) Transverse instabilities for high intensity/bunch; 6) working group introduction from ESRF experience; 7) impedance modelling: simulations, minimization; 8) report on the broadband impedance measurements and modelling workshop; 9) feedback systems for synchrotron light sources; 10) beam instabilities diagnostics; 11) harmonic cavities: the pros and cons; and 12) experimental study of fast beam-ion instabilities at PLS. This document gathers the 12 articles that were presented during these sessions.

  4. Equilibrium Electro-osmotic Instability

    CERN Document Server

    Rubinstein, Isaak

    2014-01-01

    Since its prediction fifteen years ago, electro-osmotic instability has been attributed to non-equilibrium electro-osmosis related to the extended space charge which develops at the limiting current in the course of concentration polarization at a charge-selective interface. This attribution had a double basis. Firstly, it has been recognized that equilibrium electro-osmosis cannot yield instability for a perfectly charge-selective solid. Secondly, it has been shown that non-equilibrium electro-osmosis can. First theoretical studies in which electro-osmotic instability was predicted and analyzed employed the assumption of perfect charge-selectivity for the sake of simplicity and so did the subsequent numerical studies of various time-dependent and nonlinear features of electro-osmotic instability. In this letter, we show that relaxing the assumption of perfect charge-selectivity (tantamount to fixing the electrochemical potential in the solid) allows for equilibrium electro-osmotic instability. Moreover, we s...

  5. Instability in Shocked Granular Gases

    CERN Document Server

    Sirmas, Nick; Radulescu, Matei

    2013-01-01

    Shocks in granular media, such as vertically oscillated beds, have been shown to develop instabilities. Similar jet formation has been observed in explosively dispersed granular media. Our previous work addressed this instability by performing discrete-particle simulations of inelastic media undergoing shock compression. By allowing finite dissipation within the shock wave, instability manifests itself as distinctive high density non-uniformities and convective rolls within the shock structure. In the present study we have extended this work to investigate this instability at the continuum level. We modeled the Euler equations for granular gases with a modified cooling rate to include an impact velocity threshold necessary for inelastic collisions. Our results showed a fair agreement between the continuum and discrete-particle models. Discrepancies, such as higher frequency instabilities in our continuum results may be attributed to the absence of higher order effects.

  6. Instability in shocked granular gases

    Science.gov (United States)

    Sirmas, Nick; Falle, Sam; Radulescu, Matei

    2014-05-01

    Shocks in granular media, such as vertically oscillated beds, have been shown to develop instabilities. Similar jet formation has been observed in explosively dispersed granular media. Our previous work addressed this instability by performing discrete-particle simulations of inelastic media undergoing shock compression. By allowing finite dissipation within the shock wave, instability manifests itself as distinctive high density non-uniformities and convective rolls within the shock structure. In the present study we have extended this work to investigate this instability at the continuum level. We modeled the Euler equations for granular gases with a modified cooling rate to include an impact velocity threshold necessary for inelastic collisions. Our results showed a fair agreement between the continuum and discrete-particle models. Discrepancies, such as higher frequency instabilities in our continuum results may be attributed to the absence of higher order effects.

  7. Gravitational Instabilities in Circumstellar Disks

    CERN Document Server

    Kratter, Kaitlin M

    2016-01-01

    [Abridged] Star and planet formation are the complex outcomes of gravitational collapse and angular momentum transport mediated by protostellar and protoplanetary disks. In this review we focus on the role of gravitational instability in this process. We begin with a brief overview of the observational evidence for massive disks that might be subject to gravitational instability, and then highlight the diverse ways in which the instability manifests itself in protostellar and protoplanetary disks: the generation of spiral arms, small scale turbulence-like density fluctuations, and fragmentation of the disk itself. We present the analytic theory that describes the linear growth phase of the instability, supplemented with a survey of numerical simulations that aim to capture the non-linear evolution. We emphasize the role of thermodynamics and large scale infall in controlling the outcome of the instability. Despite apparent controversies in the literature, we show a remarkable level of agreement between analyt...

  8. Gravitational Instabilities in Circumstellar Disks

    Science.gov (United States)

    Kratter, Kaitlin; Lodato, Giuseppe

    2016-09-01

    Star and planet formation are the complex outcomes of gravitational collapse and angular momentum transport mediated by protostellar and protoplanetary disks. In this review, we focus on the role of gravitational instability in this process. We begin with a brief overview of the observational evidence for massive disks that might be subject to gravitational instability and then highlight the diverse ways in which the instability manifests itself in protostellar and protoplanetary disks: the generation of spiral arms, small-scale turbulence-like density fluctuations, and fragmentation of the disk itself. We present the analytic theory that describes the linear growth phase of the instability supplemented with a survey of numerical simulations that aim to capture the nonlinear evolution. We emphasize the role of thermodynamics and large-scale infall in controlling the outcome of the instability. Despite apparent controversies in the literature, we show a remarkable level of agreement between analytic predictions and numerical results. In the next part of our review, we focus on the astrophysical consequences of the instability. We show that the disks most likely to be gravitationally unstable are young and relatively massive compared with their host star, Md/M*≥0.1. They will develop quasi-stable spiral arms that process infall from the background cloud. Although instability is less likely at later times, once infall becomes less important, the manifestations of the instability are more varied. In this regime, the disk thermodynamics, often regulated by stellar irradiation, dictates the development and evolution of the instability. In some cases the instability may lead to fragmentation into bound companions. These companions are more likely to be brown dwarfs or stars than planetary mass objects. Finally, we highlight open questions related to the development of a turbulent cascade in thin disks and the role of mode-mode coupling in setting the maximum angular

  9. Abelianization of QCD plasma instabilities

    Science.gov (United States)

    Arnold, Peter; Lenaghan, Jonathan

    2004-12-01

    QCD plasma instabilities appear to play an important role in the equilibration of quark-gluon plasmas in heavy-ion collisions in the theoretical limit of weak coupling (i.e. asymptotically high energy). It is important to understand what nonlinear physics eventually stops the exponential growth of unstable modes. It is already known that the initial growth of plasma instabilities in QCD closely parallels that in QED. However, once the unstable modes of the gauge fields grow large enough for non-Abelian interactions between them to become important, one might guess that the dynamics of QCD plasma instabilities and QED plasma instabilities become very different. In this paper, we give suggestive arguments that non-Abelian self-interactions between the unstable modes are ineffective at stopping instability growth, and that the growing non-Abelian gauge fields become approximately Abelian after a certain stage in their growth. This in turn suggests that understanding the development of QCD plasma instabilities in the nonlinear regime may have close parallels to similar processes in traditional plasma physics. We conjecture that the physics of collisionless plasma instabilities in SU(2) and SU(3) gauge theory becomes equivalent, respectively, to (i) traditional plasma physics, which is U(1) gauge theory, and (ii) plasma physics of U(1)×U(1) gauge theory.

  10. Instability of ties in compression

    DEFF Research Database (Denmark)

    Buch-Hansen, Thomas Cornelius

    2013-01-01

    Masonry cavity walls are loaded by wind pressure and vertical load from upper floors. These loads results in bending moments and compression forces in the ties connecting the outer and the inner wall in a cavity wall. Large cavity walls are furthermore loaded by differential movements from...... exact instability solutions are complex to derive, not to mention the extra complexity introducing dimensional instability from the temperature gradients. Using an inverse variable substitution and comparing an exact theory with an analytical instability solution a method to design tie...

  11. Microsatellite instability in bladder cancer

    DEFF Research Database (Denmark)

    Gonzalez-Zulueta, M; Ruppert, J M; Tokino, K;

    1993-01-01

    Somatic instability at microsatellite repeats was detected in 6 of 200 transitional cell carcinomas of the bladder. Instabilities were apparent as changes in (GT)n repeat lengths on human chromosome 9 for four tumors and as alterations in a (CAG)n repeat in the androgen receptor gene on the X...... chromosome for three tumors. Single locus alterations were detected in three tumors, while three other tumors revealed changes in two or more loci. In one tumor we found microsatellite instability in all five loci analyzed on chromosome 9. The alterations detected were either minor 2-base pair changes...

  12. Subject to Instability

    Directory of Open Access Journals (Sweden)

    Karen Bouwer

    2000-06-01

    Full Text Available For Plantier, language constitutes reality and is male dominated. Readers of texts, she says, are at a disadvantage because the author imposes a logic that we must accept in order to understand the text. The discourses shaping our social reality have the same effect. Plantier has struggled against individual voices, discourses, and the very fabric of language informed by these discourses. "Subject to Instability" examines the impact on her generic evolution of a changing sense of self, of who her interlocutors are, and of those for whom she is speaking. I argue that her increasing attempt to juggle many different voices destabilizes her "monologic," poetical voice, resulting in a blurring of generic boundaries and eventually the abandonment of poetry. Recognizing that our entry into language is a form of alienation also unsettles Plantier because it undermines the very identity that allows her to speak for others. She concludes that each woman needs to become a Subject in her own right, but she continues to struggle against dominant discourses, modeling "resisting reader" strategies. If she can no longer practice "monologic steadfastness," this does not deter her from attempting to dismantle patriarchal language and striving to make her voice prevail over others.

  13. Non-conventional Indoor GIS Layout Design of 220kV Distribution Equipment in Guangzhou Xintang Power Plant%广州新塘电厂220 kV屋内GIS非常规布置的设计

    Institute of Scientific and Technical Information of China (English)

    唐柳燕

    2014-01-01

    ∶针对广州新塘电厂2×330MW机组工程厂区布置的特殊性及局限性,文章详细分析论述了220kV配电装置采用屋内GIS型式非常规布置的设计过程及其特点,提出合适的布置方案,解决了220kV配电装置占地及出线问题,为类似工程提供借鉴。%The design and the characteristics of the non-conventional indoor GIS layout of 220kV distribution equip-ment were discussed and analyzed in the paper based on the particularity and limitation of plant layout of Guangzhou Xintang power plant, and a reasonable layout was proposed which solves the land occupation and outgoing line prob-lems of the 220kV distribution equipment and can be well referenced by similar projects.

  14. O labirinto religioso ocidental: da religião à espiritualidade. Do institucional ao não convencional The Western religious labyrinth: from religion to spirituality. From the institutional to the non-conventional

    Directory of Open Access Journals (Sweden)

    Deis Siqueira

    2008-01-01

    Full Text Available O texto recupera questões clássicas da Sociologia da Religião, tais como supremacia da sociedade, coesão social, forças morais, "membresia", modernidade racional e intelectualizada, alienação, ilusão, para refletir o labirinto religioso contemporâneo. Este é pensado, sobretudo, a partir da busca por uma religiosidade não convencional, campo religioso pluralista, trânsito, bricolagem, privatização e individualização, espiritualidade e ambientalismo, espiritualidade no contexto organizacional, "empresarização" das igrejas, espiritualização das empresas, destacando uma tendência geral no sentido de "espiritualidade sim, religião não".This article retrieves classic questions of the Sociology of Religion such as society's supremacy, social cohesion, moral forces, membership, rationalized and intellectualized modernity, alienation, and illusion to reflect the contemporary religious labyrinth. This begins mainly with the search for a non-conventional religiosity, a pluralistic religious field, transit, bricolage, privatization and individualization, spirituality and environmentalism, spirituality in the organizational context, the "entrepeneurshipping" of the churches and the spiritualization of companies, stressing a general tendency towards "spirituality yes, religion no".

  15. Atlantoaxial instability in Down's syndrome

    OpenAIRE

    J Gordon Millichap

    1987-01-01

    The radiographs and clinical evaluations of 90 children with Down’s syndrome were reassessed after an interval of 5 years in a study of atlantoaxial instability (AAI) at the Derbyshire Children’s Hospital and Infirmary, Derby, UK.

  16. Evaporative instabilities in climbing films

    Science.gov (United States)

    Hosoi, A. E.; Bush, John W. M.

    2001-09-01

    We consider flow in a thin film generated by partially submerging an inclined rigid plate in a reservoir of ethanol or methanol water solution and wetting its surface. Evaporation leads to concentration and surface tension gradients that drive flow up the plate. An experimental study indicates that the climbing film is subject to two distinct instabilities. The first is a convective instability characterized by flattened convection rolls aligned in the direction of flow and accompanied by free-surface deformations; in the meniscus region, this instability gives rise to pronounced ridge structures aligned with the mean flow. The second instability, evident when the plate is nearly vertical, takes the form of transverse surface waves propagating up the plate.

  17. Intrinsic Instability of Coronal Streamers

    CERN Document Server

    Chen, Y; Song, H Q; Shi, Q Q; Feng, S W; Xia, L D; 10.1088/0004-637X/691/2/1936

    2009-01-01

    Plasma blobs are observed to be weak density enhancements as radially stretched structures emerging from the cusps of quiescent coronal streamers. In this paper, it is suggested that the formation of blobs is a consequence of an intrinsic instability of coronal streamers occurring at a very localized region around the cusp. The evolutionary process of the instability, as revealed in our calculations, can be described as follows: (1) through the localized cusp region where the field is too weak to sustain the confinement, plasmas expand and stretch the closed field lines radially outward as a result of the freezing-in effect of plasma-magnetic field coupling; the expansion brings a strong velocity gradient into the slow wind regime providing the free energy necessary for the onset of a subsequent magnetohydrodynamic instability; (2) the instability manifests itself mainly as mixed streaming sausage-kink modes, the former results in pinches of elongated magnetic loops to provoke reconnections at one or many loc...

  18. Material Instabilities in Particulate Systems

    Science.gov (United States)

    Goddard, J. D.

    1999-01-01

    Following is a brief summary of a theoretical investigation of material (or constitutive) instability associated with shear induced particle migration in dense particulate suspensions or granular media. It is shown that one can obtain a fairly general linear-stability analysis, including the effects of shear-induced anisotropy in the base flow as well as Reynolds dilatancy. A criterion is presented here for simple shearing instability in the absence of inertia and dilatancy.

  19. Instability following total knee arthroplasty.

    Science.gov (United States)

    Rodriguez-Merchan, E Carlos

    2011-10-01

    Background Knee prosthesis instability (KPI) is a frequent cause of failure of total knee arthroplasty. Moreover, the degree of constraint required to achieve immediate and long-term stability in total knee arthroplasty (TKA) is frequently debated. Questions This review aims to define the problem, analyze risk factors, and review strategies for prevention and treatment of KPI. Methods A PubMed (MEDLINE) search of the years 2000 to 2010 was performed using two key words: TKA and instability. One hundred and sixty-five initial articles were identified. The most important (17) articles as judged by the author were selected for this review. The main criteria for selection were that the articles addressed and provided solutions to the diagnosis and treatment of KPI. Results Patient-related risk factors predisposing to post-operative instability include deformity requiring a large surgical correction and aggressive ligament release, general or regional neuromuscular pathology, and hip or foot deformities. KPI can be prevented in most cases with appropriate selection of implants and good surgical technique. When ligament instability is anticipated post-operatively, the need for implants with a greater degree of constraint should be anticipated. In patients without significant varus or valgus malalignment and without significant flexion contracture, the posterior cruciate ligament (PCL) can be retained. However, the PCL should be sacrificed when deformity exists particularly in patients with rheumatoid arthritis, previous patellectomy, previous high tibial osteotomy or distal femoral osteotomy, and posttraumatic osteoarthritis with disruption of the PCL. In most cases, KPI requires revision surgery. Successful outcomes can only be obtained if the cause of KPI is identified and addressed. Conclusions Instability following TKA is a common cause of the need for revision. Typically, knees with deformity, rheumatoid arthritis, previous patellectomy or high tibial osteotomy, and

  20. Midcarpal instability: a radiological perspective

    Energy Technology Data Exchange (ETDEWEB)

    Toms, Andoni Paul [Norfolk and Norwich University Hospital NHS Trust, Department of Radiology, Norwich, Norfolk (United Kingdom); Radiology Academy, Cotman Centre, Norwich, Norfolk (United Kingdom); Chojnowski, Adrian [Norfolk and Norwich University Hospital NHS Trust, Department of Orthopaedic Surgery, Norwich, Norfolk (United Kingdom); Cahir, John G. [Norfolk and Norwich University Hospital NHS Trust, Department of Radiology, Norwich, Norfolk (United Kingdom)

    2011-05-15

    Midcarpal instability (MCI) is the result of complex abnormal carpal motion at the midcarpal joint of the wrist. It is a form of non-dissociative carpal instability (CIND) and can be caused by various combinations of extrinsic ligament injuries that then result in one of several subtypes of MCI. The complex patterns of injury and the kinematics are further complicated by competing theories, terminology and classifications of MCI. Palmar, dorsal, ulna midcarpal instability, and capitolunate or chronic capitolunate instability are all descriptions of types of MCI with often overlapping features. Palmar midcarpal instability (PMCI) is the most commonly reported type of MCI. It has been described as resulting from deficiencies in the ulna limb of the palmar arcuate ligament (triquetrohamate-capitate) or the dorsal radiotriquetral ligaments, or both. Unstable carpal articulations can be treated with limited carpal arthrodesis or the ligamentous defects can be treated with capsulorrhaphy or ligament reconstruction. Conventional radiographic abnormalities are usually limited to volar intercalated segment instability (VISI) patterns of carpal alignment and are not specific. For many years stress view radiographs and videofluoroscopy have been the methods of choice for demonstrating carpal instability and abnormal carpal kinematics respectively. Dynamic US can be also used to demonstrate midcarpal dyskinesia including the characteristic triquetral ''catch-up'' clunk. Tears of the extrinsic ligaments can be demonstrated with MR arthrography, and probably with CT arthrography, but intact yet redundant ligaments are more difficult to identify. The exact role of these investigations in the diagnosis, categorisation and management of midcarpal instability has yet to be determined. (orig.)

  1. Instability of enclosed horizons

    Science.gov (United States)

    Kay, Bernard S.

    2015-03-01

    We point out that there are solutions to the scalar wave equation on dimensional Minkowski space with finite energy tails which, if they reflect off a uniformly accelerated mirror due to (say) Dirichlet boundary conditions on it, develop an infinite stress-energy tensor on the mirror's Rindler horizon. We also show that, in the presence of an image mirror in the opposite Rindler wedge, suitable compactly supported arbitrarily small initial data on a suitable initial surface will develop an arbitrarily large stress-energy scalar near where the two horizons cross. Also, while there is a regular Hartle-Hawking-Israel-like state for the quantum theory between these two mirrors, there are coherent states built on it for which there are similar singularities in the expectation value of the renormalized stress-energy tensor. We conjecture that in other situations with analogous enclosed horizons such as a (maximally extended) Schwarzschild black hole in equilibrium in a (stationary spherical) box or the (maximally extended) Schwarzschild-AdS spacetime, there will be similar stress-energy singularities and almost-singularities—leading to instability of the horizons when gravity is switched on and matter and gravity perturbations are allowed for. All this suggests it is incorrect to picture a black hole in equilibrium in a box or a Schwarzschild-AdS black hole as extending beyond the past and future horizons of a single Schwarzschild (/Schwarzschild-AdS) wedge. It would thus provide new evidence for 't Hooft's brick wall model while seeming to invalidate the picture in Maldacena's ` Eternal black holes in AdS'. It would thereby also support the validity of the author's matter-gravity entanglement hypothesis and of the paper ` Brick walls and AdS/CFT' by the author and Ortíz.

  2. Vector-Resonance-Multimode Instability

    Science.gov (United States)

    Sergeyev, S. V.; Kbashi, H.; Tarasov, N.; Loiko, Yu.; Kolpakov, S. A.

    2017-01-01

    The modulation and multimode instabilities are the main mechanisms which drive spontaneous spatial and temporal pattern formation in a vast number of nonlinear systems ranging from biology to laser physics. Using an Er-doped fiber laser as a test bed, here for the first time we demonstrate both experimentally and theoretically a new type of a low-threshold vector-resonance-multimode instability which inherits features of multimode and modulation instabilities. The same as for the multimode instability, a large number of longitudinal modes can be excited without mode synchronization. To enable modulation instability, we modulate the state of polarization of the lasing signal with the period of the beat length by an adjustment of the in-cavity birefringence and the state of polarization of the pump wave. As a result, we show the regime's tunability from complex oscillatory to periodic with longitudinal mode synchronization in the case of resonance matching between the beat and cavity lengths. Apart from the interest in laser physics for unlocking the tunability and stability of dynamic regimes, the proposed mechanism of the vector-resonance-multimode instability can be of fundamental interest for the nonlinear dynamics of various distributed systems.

  3. Analysis of Factors Influencing Quality of Life of Patients with Permanent Colostomy with Fish-Bone Diagram%鱼骨图对永久性肠造口人生活质量的影响因素分析

    Institute of Scientific and Technical Information of China (English)

    汤利萍; 李乐; 王霞

    2015-01-01

    目的:运用鱼骨图分析影响肠造口人生活质量的因素,为进一步提高其生活质量提供指导。方法动态追踪105例行永久性结肠造口人的资料。建立信息库,每月随访1次,持续追踪1年,了解造口人基本信息、术后并发症、造口护理情况、心理状况等,采用鱼骨图法对造口人肠造口术后生活质量的影响因素进行分析和评价。结果影响肠造口人生活质量的因素包括医生、护士、造口人及家属、社会支持。结论采用鱼骨图法能对生活质量的影响因素进行全面有效分析,了解肠造口人术后生活状态的原因,为其自我管理和护理提供全面、有效的指导。%Objective To analyze the factors influencing the quality of life of patients with per-manent colostomy using fish-bone diagram,and to provide guides for improving the quality of life of patients with permanent colostomy.Methods Data of 105 patients with permanent colostomy were dynamically tracked,and the database was established.The follow-up was performed once per month for 1 year to know the basic information,postoperative complications,nursing situation and psychological status of patients.In addition,the factors influencing the quality of life of pa-tients with permanent colostomy were analyzed and evaluated using fish-bone diagram.Results The factors influencing the quality of life of patients with permanent colostomy included doctors, nurses,patients and their families,and social supports.Conclusion Fish-bone diagram can be used for comprehensively and effectively analyzing the factors influencing the life of quality,un-derstanding the state of life and providing guides for self-management and nursing in patients with permanent colostomy.

  4. Fishbone Diagram and Rotation Forest Predictive Model of Raw Cotton Quality for Yarn Quality%原棉质量对纱线质量的鱼骨图-旋转森林预测模型

    Institute of Scientific and Technical Information of China (English)

    雷英娜

    2015-01-01

    原棉质量的影响因素与纱线质量的关系具有不确定性,针对该问题,综合应用相关分析法、鱼骨图理论及旋转森林原理构建原棉质量对纱线质量的预测模型.采用相关分析法及原因型鱼骨图模型分析原棉影响因素与纱线质量的关联度,计算各因素权重.用实测18组纺纱数据对影响因素加权的旋转森林模型进行训练,测试结果良好.用13组数据作为测试数据,进行量预测,并且与其他预测模型进行对比.研究结果表明:鱼骨图模型可获得因素与纱线质量的关系,量化输入变量的重要性;结合旋转森林预测模型能更好地考虑各因素对纱线质量的综合影响,与其他方法进行比较,验证了鱼骨图-旋转森林模型在纱线质量预测中具有较高的精确度.%The relationship between factors of raw cotton quality and yarn quality is uncertain,so correlation analysis, fishbone diagram, and rotation forest algorithm are used to make the model of yarn quality prediction model from the perspective of quantitative analysis. Among them, correlation analysis and fishbone diagram are used to analysis the correlation degree of influence factors of raw cotton and yarn quality . Then the correlation degree is as the weight to predict by rotation forest algorithm.Eighteen groups of data are taken as training data. Additional thirteen groups as test data to verify it and compare with the other prediction method. The results show that the fishbone diagram can obtain the relationships among indexes and yarn quality, and the indexes' weights.The proposed method considering the mainfold factors can improve the prediction precision of raw cotton quality for yarn quality.Through compared with the other test data,the result shows that the model has a high accuracy.

  5. Elliptic and magneto-elliptic instabilities

    Directory of Open Access Journals (Sweden)

    Lyra Wladimir

    2013-04-01

    Full Text Available Vortices are the fundamental units of turbulent flow. Understanding their stability properties therefore provides fundamental insights on the nature of turbulence itself. In this contribution I briely review the phenomenological aspects of the instability of elliptic streamlines, in the hydro (elliptic instability and hydromagnetic (magneto-elliptic instability regimes. Vortex survival in disks is a balance between vortex destruction by these mechanisms, and vortex production by others, namely, the Rossby wave instability and the baroclinic instability.

  6. High-level production of tetraacetyl phytosphingosine (TAPS) by combined genetic engineering of sphingoid base biosynthesis and L-serine availability in the non-conventional yeast Pichia ciferrii.

    Science.gov (United States)

    Schorsch, Christoph; Köhler, Tim; Andrea, Heiko; Boles, Eckhard

    2012-03-01

    The non-conventional yeast Pichia ciferrii is known to secrete the sphingoid long-chain base phytosphingosine in a tetraacetylated form (TAPS). Sphingolipids are important ingredients in cosmetic applications as they play important roles in human skin. Our work aimed to improve TAPS production by genetic engineering of P. ciferrii. In the first step we improved precursor availability by blocking degradation of L-serine, which is condensed with palmitoyl-CoA by serine palmitoyltransferase in the first committed step of sphingolipid biosynthesis. Successive deletion of two genes, SHM1 and SHM2, encoding L-serine hydroxymethyltransferases, and of CHA1 encoding L-serine deaminase, resulted in a strain producing 65 mg((TAPS))g(-1)((cdw)), which is a threefold increase in comparison with the parental strain. Attempts to increase the metabolic flux into and through the L-serine biosynthesis pathway did not improve TAPS production. However, genetic engineering of the sphingolipid pathway further increased secretion of TAPS. Blocking of sphingoid long-chain base phosphorylation by deletion of the LCB kinase gene PcLCB4 resulted in a further increase in TAPS production by 78% and significant secretion of the direct precursor of phytosphingosine, sphinganin, in a triacetylated form (TriASa). Overproduction of two serine palmitoyltransferase subunits, Lcb1 and Lcb2, together with a deletion of the gene ORM12 encoding a putative negative regulator of sphingolipid synthesis resulted in a strain producing 178 mg((TAPS))g(-1)((cdw)). Additional overproduction of the C4-hydroxylase Syr2 converting sphinganine to phytosphingosine reduced TriASa production and further improved TAPS production. The final recombinant P. ciferrii strain produced up to 199 mg((TAPS))g(-1)((cdw)) with a maximal production rate of 8.42 mg×OD(600nm)(-1)h(-1) and a titer of about 2 g L(-1), and should be applicable for industrial TAPS production.

  7. The Development and Utilization of Non Conventional Feed Corn citric Acid Slag%非常规饲料玉米柠檬酸渣的开发利用

    Institute of Scientific and Technical Information of China (English)

    范先超

    2014-01-01

    开发非常规饲料是缓解饲料资源不足、降低畜禽养殖成本、提高畜牧业经济效益的重要途径。玉米柠檬酸渣是柠檬酸生产企业副产品,含有丰富的营养物质,用作畜禽配合饲料原料有着很好的开发前景。文章对玉米柠檬酸渣饲料资源特点、营养特性、在动物生产中应用效果与研究现状、存在问题等进行了详细分析,并提出了开发利用时需要解决的问题。%The development of non conventional feed is the important way to solve the lack of resources, reduce the feed of livestock and poultry breeding cost and improve the economic benefit of animal husbandry. Corn citric acid slag is a by-product of citric acid production enterprises, rich in nutrients, used as livestock feed raw materials have very good developing prospect. This paper conducts a detailed analysis on the characteristics of the feed resources, application effect of maize nutrition characteristics, citric acid residue in animal production and the present situation, existing problems and puts forward the exploitation problem to solve.

  8. 鱼骨形网格上二阶方程混合元的超收敛%SUPERCONVERGENCE OF THE MIXED FINITE ELEMENT FOR SECOND ORDER EQUATION ON FISHBONE SHAPE MESHES

    Institute of Scientific and Technical Information of China (English)

    林甲富; 林群

    2004-01-01

    In this paper, superconvergence of the lowest order Raviart-Thomas mixed finite element approximation for second order Neumann boundary value problem on fishbone shape meshes is analyzed. The main term of the error between the exact solution and the finite element interpolating function is determined by Bramble-Hilbert lemma on the individual finite element. A part of the main term of the error on two adjacent finite elements can be cancelled along the special direction, and thus the higher order error estimate is obtained on the whole domain by summation. Compared with the general finite element error estimate,the convergence rate can be increased from order one to order two in L2-norm by postprocessing superconvergence technique.

  9. “PDCA +鱼刺图分析法”的增压器装配质量改善%An Assembly Quality Improvement of Turbocharger Based on PDCA Plus Fishbone Diagram Analysis

    Institute of Scientific and Technical Information of China (English)

    陈文; 张力; 蒋建军

    2015-01-01

    In order to improve the turbocharger′s assembly quality of S company , an improvement is made on the traditional fishbone diagram , based on the concept of total quality management , in which two impor-tant factors, i.e.design and inspect , are added.The improved fishbone diagram method is then used to analyze the floating bearing leakage accident that happened in turbocharger assembly line of S company , and identify the causes and key reasons .During the whole process , the PDCA cycle management theory is utilized to formulate corresponding measures and consolidate the results .From early 2012 to the end of 2013 , the leakage accidents have decreased from three to zero , which means that the quality target is reached .%质量控制是机械制造过程中不可或缺的一环,为提升S厂一半自动化增压器装配线的装配质量,文章结合全面质量管理理念,对传统鱼刺图进行分析改进,增加了“设计”与“检测”两大分析因素,并针对S厂增压器装配流水线出现的漏装浮动轴承质量事故,运用改进的鱼刺图分析法进行原因分析和要因确定,同时贯穿PDCA循环管理理论,制定了相应对策措施,并予以实施和巩固,使漏装事故从2012年初到2013年底,由3起降低到0起,从而达到了质量控制目标。

  10. Integrated analysis of fishbone and evolution laws on product failure prediction and problem solving%集成鱼骨分析与进化法则的产品失效预测及问题求解

    Institute of Scientific and Technical Information of China (English)

    陈喜; 李文强; 李彦; 王伟; 李剑

    2014-01-01

    基于传统FM EA在失效问题分析与解决方面的不足,提出了一种集成鱼骨图、FM EA和进化法则的创新设计方法。利用鱼骨图层次化分析辅助FM EA全面挖掘可能发生的失效模式,按照FM EA的规范表达分析失效模式并确定风险优先指数RPN ,然后运用进化法则针对失效问题进行有效的解决,提高了解决问题的效率。最后通过铁路减振的示例验证了该集成方法的可行性。%Based on the shortcomings of traditional FM EA in analyzing problems and finding solu-tions ,an innovative design method integrated with fishbone diagram ,FMEA and evolution laws was proposed .This method used the hierarchical analysis of fishbone diagram to assist FMEA fully excavate possible failure modes ,then analyzed failure modes according to the standard ex-pression of FMEA and determined the Risk Priority Number (RPN) .By adopting evolution laws , the method can solve the failure problems effectively and efficiently .T his paper also verifies the feasibility of this integrated method with an example of vibration damping design on rail track .

  11. Interfacial instabilities and Kapitsa pendula

    Science.gov (United States)

    Krieger, Madison

    2015-11-01

    Determining the critera for onset and amplitude growth of instabilities is one of the central problems of fluid mechanics. We develop a parallel between the Kapitsa effect, in which a pendulum subject to high-frequency low-amplitude vibrations becomes stable in the inverted position, and interfaces separating fluids of different density. It has long been known that such interfaces can be stabilized by vibrations, even when the denser fluid is on top. We demonstrate that the stability diagram for these fluid interfaces is identical to the stability diagram for an appopriate Kapitsa pendulum. We expand the robust, ``dictionary''-type relationship between Kapitsa pendula and interfacial instabilities by considering the classical Rayleigh-Taylor, Kelvin-Helmholtz and Plateau instabilities, as well as less-canonical examples ranging in scale from the micron to the width of a galaxy.

  12. Interfacial Instability during Granular Erosion.

    Science.gov (United States)

    Lefebvre, Gautier; Merceron, Aymeric; Jop, Pierre

    2016-02-12

    The complex interplay between the topography and the erosion and deposition phenomena is a key feature to model granular flows such as landslides. Here, we investigated the instability that develops during the erosion of a wet granular pile by a dry dense granular flow. The morphology and the propagation of the generated steps are analyzed in relation to the specific erosion mechanism. The selected flowing angle of the confined flow on a dry heap appears to play an important role both in the final state of the experiment, and for the shape of the structures. We show that the development of the instability is governed by the inertia of the flow through the Froude number. We model this instability and predict growth rates that are in agreement with the experiment results.

  13. Evaporative Instability in Binary Mixtures

    Science.gov (United States)

    Narayanan, Ranga; Uguz, Erdem

    2012-11-01

    In this talk we depict the physics of evaporative convection for binary systems in the presence of surface tension gradient effects. Two results are of importance. The first is that a binary system, in the absence of gravity, can generate an instability only when heated from the vapor side. This is to be contrasted with the case of a single component where instability can occur only when heated from the liquid side. The second result is that a binary system, in the presence of gravity, will generate an instability when heated from either the vapor or the liquid side provided the heating is strong enough. In addition to these results we show the conditions at which interfacial patterns can occur. Support from NSF OISE 0968313, Partner Univ. Fund and a Chateaubriand Fellowship is acknowledged.

  14. Laboratory blast wave driven instabilities

    Science.gov (United States)

    Kuranz, Carolyn

    2008-11-01

    This presentation discusses experiments involving the evolution of hydrodynamic instabilities in the laboratory under high-energy-density (HED) conditions. These instabilities are driven by blast waves, which occur following a sudden, finite release of energy, and consist of a shock front followed by a rarefaction wave. When a blast wave crosses an interface with a decrease in density, hydrodynamic instabilities will develop. Instabilities evolving under HED conditions are relevant to astrophysics. These experiments include target materials scaled in density to the He/H layer in SN1987A. About 5 kJ of laser energy from the Omega Laser facility irradiates a 150 μm plastic layer that is followed by a low-density foam layer. A blast wave structure similar to those in supernovae is created in the plastic layer. The blast wave crosses an interface having a 2D or 3D sinusoidal structure that serves as a seed perturbation for hydrodynamic instabilities. This produces unstable growth dominated by the Rayleigh-Taylor (RT) instability in the nonlinear regime. We have detected the interface structure under these conditions using x-ray backlighting. Recent advances in our diagnostic techniques have greatly improved the resolution of our x-ray radiographic images. Under certain conditions, the improved images show some mass extending beyond the RT spike and penetrating further than previously observed or predicted by current simulations. The observed effect is potentially of great importance as a source of mass transport to places not anticipated by current theory and simulation. I will discuss the amount of mass in these spike extensions, the associated uncertainties, and hypotheses regarding their origin We also plan to show comparisons of experiments using single mode and multimode as well as 2D and 3D initial conditions. This work is sponsored by DOE/NNSA Research Grants DE-FG52-07NA28058 (Stewardship Sciences Academic Alliances) and DE-FG52-04NA00064 (National Laser User

  15. Telomere dysfunction and chromosome instability

    Energy Technology Data Exchange (ETDEWEB)

    Murnane, John P., E-mail: jmurnane@radonc.ucsf.edu [Department of Radiation Oncology, University of California San Francisco, 2340 Sutter Street, San Francisco, CA 94143-1331 (United States)

    2012-02-01

    The ends of chromosomes are composed of a short repeat sequence and associated proteins that together form a cap, called a telomere, that keeps the ends from appearing as double-strand breaks (DSBs) and prevents chromosome fusion. The loss of telomeric repeat sequences or deficiencies in telomeric proteins can result in chromosome fusion and lead to chromosome instability. The similarity between chromosome rearrangements resulting from telomere loss and those found in cancer cells implicates telomere loss as an important mechanism for the chromosome instability contributing to human cancer. Telomere loss in cancer cells can occur through gradual shortening due to insufficient telomerase, the protein that maintains telomeres. However, cancer cells often have a high rate of spontaneous telomere loss despite the expression of telomerase, which has been proposed to result from a combination of oncogene-mediated replication stress and a deficiency in DSB repair in telomeric regions. Chromosome fusion in mammalian cells primarily involves nonhomologous end joining (NHEJ), which is the major form of DSB repair. Chromosome fusion initiates chromosome instability involving breakage-fusion-bridge (B/F/B) cycles, in which dicentric chromosomes form bridges and break as the cell attempts to divide, repeating the process in subsequent cell cycles. Fusion between sister chromatids results in large inverted repeats on the end of the chromosome, which amplify further following additional B/F/B cycles. B/F/B cycles continue until the chromosome acquires a new telomere, most often by translocation of the end of another chromosome. The instability is not confined to a chromosome that loses its telomere, because the instability is transferred to the chromosome donating a translocation. Moreover, the amplified regions are unstable and form extrachromosomal DNA that can reintegrate at new locations. Knowledge concerning the factors promoting telomere loss and its consequences is

  16. Stringy bounces and gradient instabilities

    CERN Document Server

    Giovannini, Massimo

    2017-01-01

    Bouncing solutions are obtained from a generally covariant action characterized by a potential which is a nonlocal functional of the dilaton field at two separated space-time points. Gradient instabilities are shown to arise in this context but they are argued to be nongeneric. After performing a gauge-invariant and frame-invariant derivation of the evolution equations of the fluctuations, a heuristic criterium for the avoidance of pathological instabilities is proposed and corroborated by a number of explicit examples that turn out to be compatible with a quasi-flat spectrum of curvature inhomogeneities for typical wavelengths larger than the Hubble radius.

  17. Research on aviation fuel instability

    Science.gov (United States)

    Baker, C. E.; Bittker, D. A.; Cohen, S. M.; Seng, G. T.

    1984-01-01

    The problems associated with aircraft fuel instability are discussed. What is currently known about the problem is reviewed and a research program to identify those areas where more research is needed is discussed. The term fuel instability generally refers to the gums, sediments, or deposits which can form as a result of a set of complex chemical reactions when a fuel is stored for a long period at ambient conditions or when the fuel is thermally stressed inside the fuel system of an aircraft.

  18. Mechanical Instabilities of Biological Tubes

    Science.gov (United States)

    Hannezo, Edouard; Prost, Jacques; Joanny, Jean-François

    2012-07-01

    We study theoretically the morphologies of biological tubes affected by various pathologies. When epithelial cells grow, the negative tension produced by their division provokes a buckling instability. Several shapes are investigated: varicose, dilated, sinuous, or sausagelike. They are all found in pathologies of tracheal, renal tubes, or arteries. The final shape depends crucially on the mechanical parameters of the tissues: Young’s modulus, wall-to-lumen ratio, homeostatic pressure. We argue that since tissues must be in quasistatic mechanical equilibrium, abnormal shapes convey information as to what causes the pathology. We calculate a phase diagram of tubular instabilities which could be a helpful guide for investigating the underlying genetic regulation.

  19. Hydromagnetic Instabilities in Neutron Stars

    CERN Document Server

    Lasky, Paul D; Kokkotas, Kostas D; Glampedakis, Kostas

    2011-01-01

    We model the non-linear ideal magnetohydrodynamics of poloidal magnetic fields in neutron stars in general relativity assuming a polytropic equation of state. We identify familiar hydromagnetic modes, in particular the 'sausage/varicose' mode and 'kink' instability inherent to poloidal magnetic fields. The evolution is dominated by the kink instability, which causes a cataclysmic reconfiguration of the magnetic field. The system subsequently evolves to new, non-axisymmetric, quasi-equilibrium end-states. The existence of this branch of stable quasi-equilibria may have consequences for magnetar physics, including flare generation mechanisms and interpretations of quasi-periodic oscillations.

  20. Political instability and illegal immigration.

    Science.gov (United States)

    Campos, J E; Lien, D

    1995-01-01

    "Economic theory suggests that transnational migration results from the push-pull effect of wage differentials between host and source countries. In this paper, we argue that political instability exacerbates the migration flow, with greater instability leading to relatively larger flows. We conclude then that an optimal solution to the illegal immigration problem requires proper coordination of immigration and foreign policies by the host country. A narrow preoccupation with tougher immigration laws is wasteful and may be marginally effective." Emphasis is on the United States as a host country.

  1. Undulation Instability of Epithelial Tissues

    CERN Document Server

    Basan, Markus; Prost, Jacques; Risler, Thomas; 10.1103/PhysRevLett.106.158101

    2011-01-01

    Treating the epithelium as an incompressible fluid adjacent to a viscoelastic stroma, we find a novel hydrodynamic instability that leads to the formation of protrusions of the epithelium into the stroma. This instability is a candidate for epithelial fingering observed in vivo. It occurs for sufficiently large viscosity, cell-division rate and thickness of the dividing region in the epithelium. Our work provides physical insight into a potential mechanism by which interfaces between epithelia and stromas undulate, and potentially by which tissue dysplasia leads to cancerous invasion.

  2. Secondary instabilities of linearly heated falling films

    Institute of Scientific and Technical Information of China (English)

    HU Jun; SUN Dejun; HU Guohui; YIN Xieyuan

    2005-01-01

    Secondary instabilities of linearly heated failing films are studied through three steps. Firstly, the analysis of the primary linear instability on Miladinova's long wave equation of the linearly heated film is performed. Secondly, the similar Landau equation is derived through weak nonlinear theory, and a two-dimensional nonlinear saturation solution of primary instability is obtained within the weak nonlinear domain. Thirdly, the secondary (three-dimensional) instability of the two-dimensional wave is studied by the Floquet theorem.Our secondary instability analysis shows that the Marangoni number has destabilization effect on the secondary instability.

  3. Single-parenthood by choice: Children’s socialization processes into a non-conventional family model Monoparentalidad por elección: procesos de socialización de los hijos/as en un modelo familiar no convencional

    Directory of Open Access Journals (Sweden)

    David Poveda

    2011-07-01

    Full Text Available In this article we present part of our findings from a research project focused on single-parent families by choice. The study collected data in three autonomous communities in Spain and includes interviews with mothers involved in single parent-projects (through adoption, foster parenting, assisted reproductive technologies or sexual fertilization through a known donor and their children about their family experiences, observations in different formative, associative and virtual spaces in which these families participate and a compilation of different documents on parenthood by choice. We focus on the way in which the children we have studied build their own non-conventional family model. We understand the construction of this model as a process of co-construction of the child's subjectivity in which mothers and other socializing agents play an active role.En este artículo presentamos parte de los resultados de un proyecto de investigación centrado en familias monoparentales por elección. El estudio recoge datos en tres comunidades autónomas del Estado Español e incluye entrevistas a madres embarcadas en proyectos familiares en solitario (a través de adopción internacional, acogimiento permanente, técnicas de reproducción asistida y fecundación sexual con donante conocido y a sus hijos/as sobre sus experiencias familiares, observación de diferentes espacios virtuales, formativos y asociativos en los que estas familias participan y recopilación de diferentes documentos en torno a la monoparentalidad por elección. Nos centraremos en examinar el modo en que los niños y las niñas de la muestra estudiada construyen su propio modelo de familia no convencional. Entendemos que la construcción del modelo familiar es, en realidad, un proceso de co-construcción de la subjetividad del hijo/a, en que las madres y otros agentes socializadores juegan un papel activo.

     

  4. Edge instabilities of topological superconductors

    Science.gov (United States)

    Hofmann, Johannes S.; Assaad, Fakher F.; Schnyder, Andreas P.

    2016-05-01

    Nodal topological superconductors display zero-energy Majorana flat bands at generic edges. The flatness of these edge bands, which is protected by time-reversal and translation symmetry, gives rise to an extensive ground-state degeneracy. Therefore, even arbitrarily weak interactions lead to an instability of the flat-band edge states towards time-reversal and translation-symmetry-broken phases, which lift the ground-state degeneracy. We examine the instabilities of the flat-band edge states of dx y-wave superconductors by performing a mean-field analysis in the Majorana basis of the edge states. The leading instabilities are Majorana mass terms, which correspond to coherent superpositions of particle-particle and particle-hole channels in the fermionic language. We find that attractive interactions induce three different mass terms. One is a coherent superposition of imaginary s -wave pairing and current order, and another combines a charge-density-wave and finite-momentum singlet pairing. Repulsive interactions, on the other hand, lead to ferromagnetism together with spin-triplet pairing at the edge. Our quantum Monte Carlo simulations confirm these findings and demonstrate that these instabilities occur even in the presence of strong quantum fluctuations. We discuss the implications of our results for experiments on cuprate high-temperature superconductors.

  5. Lending sociodynamics and economic instability

    Science.gov (United States)

    Hawkins, Raymond J.

    2011-11-01

    We show how the dynamics of economic instability and financial crises articulated by Keynes in the General Theory and developed by Minsky as the Financial Instability Hypothesis can be formalized using Weidlich’s sociodynamics of opinion formation. The model addresses both the lending sentiment of a lender in isolation as well as the impact on that lending sentiment of the behavior of other lenders. The risk associated with lending is incorporated through a stochastic treatment of loan dynamics that treats prepayment and default as competing risks. With this model we are able to generate endogenously the rapid changes in lending opinion that attend slow changes in lending profitability and find these dynamics to be consistent with the rise and collapse of the non-Agency mortgage-backed securities market in 2007/2008. As the parameters of this model correspond to well-known phenomena in cognitive and social psychology, we can both explain why economic instability has proved robust to advances in risk measurement and suggest how policy for reducing economic instability might be formulated in an experimentally sound manner.

  6. The Chemistry of Beer Instability

    Science.gov (United States)

    Stewart, Graham G.

    2004-01-01

    Brewing of beer, one of the oldest biotechnology industries was one of the earliest processes to be undertaken on commercial basis. Biological instability involves contamination of bacteria, yeast, or mycelia fungi and there is always a risk in brewing that beer can become contaminated by micro-organisms.

  7. Size effects on cavitation instabilities

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2006-01-01

    In metal-ceramic systems the constraint on plastic flow leads to so high stress triaxialities that cavitation instabilities may occur. If the void radius is on the order of magnitude of a characteristic length for the metal, the rate of void growth is reduced, and the possibility of unstable cavi...... as the void grows to a size well above the characteristic material length....

  8. Waves and instabilities in plasmas

    CERN Document Server

    Chen Liu

    1987-01-01

    The topics covered in these notes are selective and tend to emphasize more on kinetic-theory approaches to waves and instabilities in both uniform and non-uniform plasmas, students are assumed to have some basic knowledge of plasma dynamics in terms of single-particle and fluid descriptions.

  9. GENETIC INSTABILITY IN CERVICAL CARCINOMA

    Institute of Scientific and Technical Information of China (English)

    赵旻; 伍欣星; 邱小萍; 李晖; 戴天力; 谭云

    2002-01-01

    Objective: The role of human papillomavirus (HPV) in the development of cervical carcinoma has been clearly established but other factors could be involved in cervical tumorigenesis such as loss of heterozygosity (LOH) and microsatellite instability (MI). The aim of the present study was to investigate the genetic instability in cervical carcinoma tissues and provide evidence for discoveringnew tumor suppressor genes and screening diagnostic molecular marker of cervical carcinoma. Methods: Fifty primary cervical carcinoma samples from high-incidence area were analyzed by PCR for HPV16 infection, LOH and microsatellite instability. Results: HPV16 was detected in 88% of the cases. Sixty-six percent of total cases showed LOH with no more than 3 different loci per case. The highest frequency of the allelic loss was found in D18S474 (18q21, 40.5%). MI was detected in 4 cases (8%) only. Conclusion: Different percentages of LOH on specific chromosomal regions were found and MI was very infrequent in cervical carcinoma. The putative suppressor gene(s) could be located on specific chromosome regions such as 18q, and genetic instability could be involved in cervical tumorigenesis.

  10. Singlet and triplet instability theorems

    Science.gov (United States)

    Yamada, Tomonori; Hirata, So

    2015-09-01

    A useful definition of orbital degeneracy—form-degeneracy—is introduced, which is distinct from the usual energy-degeneracy: Two canonical spatial orbitals are form-degenerate when the energy expectation value in the restricted Hartree-Fock (RHF) wave function is unaltered upon a two-electron excitation from one of these orbitals to the other. Form-degenerate orbitals tend to have isomorphic electron densities and occur in the highest-occupied and lowest-unoccupied molecular orbitals (HOMOs and LUMOs) of strongly correlated systems. Here, we present a mathematical proof of the existence of a triplet instability in a real or complex RHF wave function of a finite system in the space of real or complex unrestricted Hartree-Fock wave functions when HOMO and LUMO are energy- or form-degenerate. We also show that a singlet instability always exists in a real RHF wave function of a finite system in the space of complex RHF wave functions, when HOMO and LUMO are form-degenerate, but have nonidentical electron densities, or are energy-degenerate. These theorems provide Hartree-Fock-theory-based explanations of Hund's rule, a singlet instability in Jahn-Teller systems, biradicaloid electronic structures, and a triplet instability during some covalent bond breaking. They also suggest (but not guarantee) the spontaneous formation of a spin density wave (SDW) in a metallic solid. The stability theory underlying these theorems extended to a continuous orbital-energy spectrum proves the existence of an oscillating (nonspiral) SDW instability in one- and three-dimensional homogeneous electron gases, but only at low densities or for strong interactions.

  11. Observation of Parametric Instability in Advanced LIGO

    CERN Document Server

    Evans, Matthew; Fritschel, Peter; Miller, John; Barsotti, Lisa; Martynov, Denis; Brooks, Aidan; Coyne, Dennis; Abbott, Rich; Adhikari, Rana; Arai, Koji; Bork, Rolf; Kells, Bill; Rollins, Jameson; Smith-Lefebvre, Nicolas; Vajente, Gabriele; Yamamoto, Hiroaki; Derosa, Ryan; Effler, Anamaria; Kokeyama, Keiko; Betzweiser, Joseph; Frolov, Valera; Mullavey, Adam; O`Reilly, Brian; Dwyer, Sheila; Izumi, Kiwamu; Kawabe, Keita; Landry, Michael; Sigg, Daniel; Ballmer, Stefan; Massinger, Thomas J; Staley, Alexa; Mueller, Chris; Grote, Hartmut; Ward, Robert; King, Eleanor; Blair, David; Ju, Li; Zhao, Chunnong

    2015-01-01

    Parametric instabilities have long been studied as a potentially limiting effect in high-power interferometric gravitational wave detectors. Until now, however, these instabilities have never been observed in a kilometer-scale interferometer. In this work we describe the first observation of parametric instability in an Advanced LIGO detector, and the means by which it has been removed as a barrier to progress.

  12. Analogy between thermal convective and magnetohydrodynamic instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Valdmanis, Ya.Ya.; Kukainis, O.A.

    1977-01-01

    An examination is made of the analogy between thermo-convective instability and instability produced by various electromagnetic forces both in steady and alternating thermal and electromagnetic fields. An example is given for calculating an assumed bubble instability which could occur in an alternating magnetic field. 17 references.

  13. Amplitude Equation for Instabilities Driven at Deformable Surfaces - Rosensweig Instability

    Science.gov (United States)

    Pleiner, Harald; Bohlius, Stefan; Brand, Helmut R.

    2008-11-01

    The derivation of amplitude equations from basic hydro-, magneto-, or electrodynamic equations requires the knowledge of the set of adjoint linear eigenvectors. This poses a particular problem for the case of a free and deformable surface, where the adjoint boundary conditions are generally non-trivial. In addition, when the driving force acts on the system via the deformable surface, not only Fredholm's alternative in the bulk, but also the proper boundary conditions are required to get amplitude equations. This is explained and demonstrated for the normal field (or Rosensweig) instability in ferrofluids as well as in ferrogels. An important aspect of the problem is its intrinsic dynamic nature, although at the end the instability is stationary. The resulting amplitude equation contains cubic and quadratic nonlinearities as well as first and (in the gel case) second order time derivatives. Spatial variations of the amplitudes cannot be obtained by using simply Newell's method in the bulk.

  14. Competing structural instabilities in cubic perovskites

    CERN Document Server

    Vanderbilt, D

    1994-01-01

    We study the antiferrodistortive instability and its interaction with ferroelectricity in cubic perovskite compounds. Our first-principles calculations show that coexistence of both instabilities is very common. We develop a first-principles scheme to study the thermodynamics of these compounds when both instabilities are present, and apply it to SrTiO$_3$. We find that increased pressure enhances the antiferrodistortive instability while suppressing the ferroelectric one. Moreover, the presence of one instability tends to suppress the other. A very rich $P$--$T$ phase diagram results.

  15. Fishbone diagram for managing nursing adverse events at department of obstetrics and gynecology%鱼骨图在妇产科护理不良事件管理中的应用观察

    Institute of Scientific and Technical Information of China (English)

    容玉甜; 李绮华; 罗雨慈

    2015-01-01

    目的 观察鱼骨图分析法在妇产科护理不良事件管理中的应用效果.方法 采用历史对照研究,将实施鱼骨图分析法后的妇产科住院患者632例作为观察组,实施前的591例患者作为对照组,比较两组护理不良事件发生情况.结果 实施前存档的护理不良事件发生率为5.08%,实施后下降为0.63% (P<0.05).每月护理差错包括处置医嘱错误、给药错误、新生儿脐部感染、红外线灼伤或烫伤等护理差错或不良事件发生例次明显减少,与实施前比较差异具有统计学意义(P<0.05).患者投诉低于实施前(P<0.05).结论 鱼骨图分析法具有简便实用,分析问题一目了然的优点,责任明确,促进了护士对出现的不良事件积极上报,利于原因分析加以避免,从而降低其发生率.%Objective To observe the application effect of fishbone diagram analysis method in the management of nursing adverse events at the departments of gynecology and obstetrics.Methods Historical control study was applied.632 patients hospitalized into the department of gynecology and obstetrics after applying fishbone diagram analysis for managing nursing adverse events were set as an observation group,591 patients before then as a control group.The incidences of nursing adverse events were compared between the two groups.Results The incidence of nursing adverse events was 5.08% before and was 0.63% after the application (P < 0.05).The nursing errors of every month,including the disposal of prescribing errors,medication errors,neonatal umbilical infection,burn or scald infrared nursing errors,etc.or adverse events significantly decreased after the application,with statistical differences from those before the application (P < 0.05).The patients complained less after the application (P<0.05).Conclusions Fishbone diagram analysis method is simple and practical,can analyze the problems clearly,clear the responsibilities,and make the nurses

  16. Fishbone diagram reduces the incidence of blood residual after sealing tube indwelling needle%应用鱼骨图在降低封管后留置针内残留血液的作用

    Institute of Scientific and Technical Information of China (English)

    李敬霞; 庞花妮; 罗丹; 桂丽

    2014-01-01

    目的:了解心血管疾病患者封管后静脉留置针内残留血液的情况,探讨应用鱼骨图对降低封管后留置针内残留血液的作用。方法按入院时间先后次序,将293例(1035例次)行静脉留置针封管的心血管疾病患者设为对照组,将272例(1276例次)行静脉留置针封管的心血管疾病患者设为实验组。对照组采用常规静脉留置针封管方法;实验组应用鱼骨图找出影响留置针内残留血液的关键因素,制订和实施针对性干预措施,比较两组患者留置针内残留血液发生率的差异。结果封管后,实验组患者留置针内残留血液发生率低于对照组,两组比较,差异有统计学意义(P<0.05)。结论通过应用鱼骨图找出影响心血管疾病患者留置针内残留血液的关键因素,采用针对性干预措施,可降低封管后留置针内残留血液发生率。%Objective To investigate the influence of fishbone diagram in the incidence of blood residual after sealing tube indwelling needle in cardiovascular disease patients.Methods Two hundred and ninety-three patients(1,035 times)with sealing tube intravenous indwelling needle were assigned into control group and another 272 ones(1,276 times)with the needle into experiment group according to admission sequence. In the former group the method of conventionally sealing the tube for intravenous indwelling needle was applied and in the latter,fishbone diagram was applied to analyze the key factors for blood residuals and regulate pertinent measures for effective sealing of tube.The two groups were compared in terms of incidence of blood residuals.Result The incidence of blood residuals in the experiment group was significantly lower than that in the control group(P<0.05).Conclusion The fishbone diagram is effective in reducing the incidence of blood residuals after sealing the tube for intravenous indwelling needle by way of taking effective

  17. Fishbone diagram analysis on the causes of violent attacks of psychiatric inpatients%鱼骨图法分析精神科住院患者暴力攻击原因

    Institute of Scientific and Technical Information of China (English)

    郑书传; 杨薇薇

    2014-01-01

    Objective To investigate the use of fishbone diagram analysis on the causes of violent attacks among psychiatric inpatients .Methods Totals of 327 cases of violent attacks psychiatric inpatients were analyzed in order to find the reasons for violent attacks using the fishbone diagram .Results The causes of violent attacks could be summarized as patient factors , family factors, staff factors, environmental factors and management factors . Patient factors according to the previous history of violent attacks were the highest , accounting for 64 .5%.Then the family factors due to blunt attitude of family members accounted for 19 .6%. The highest reason of staff factors was bad service attitude , accounting for 30.0%.The highest nursing management factor was closed-end management, accounting for 61.8%.The highest environment factor was because the wards were too crowded and noisy , accounting for 30.9%.Conclusions Fishbone diagram, used for analysis the causes violent attacks of psychiatric inpatients , is simple and practical .It provides a basis and a strong guarantee for the further implementation of continuous quality improvement in nursing safety .%目的:探讨运用鱼骨图分析精神科住院患者暴力攻击的原因。方法通过查阅不良事件讨论登记表、病历等分析327例发生暴力攻击行为的精神科住院患者的相关资料,查找暴力攻击的原因,绘制鱼骨图。结果精神科住院患者暴力攻击的原因可概括为患者因素、家属因素、工作人员因素、环境因素和管理因素,其中患者因素中最高的是既往暴力攻击史,占64.5%;家属因素中最高的是家属对患者的态度生硬、冷漠,占19.6%;工作人员因素中最高的是服务态度不好、说话太生硬,占30.0%;护理管理因素中最高的是封闭式管理,占61.8%;环境因素中最高的是病房拥挤嘈杂,占30.9%。结论鱼骨图用于精神科住院患者暴力攻

  18. Quad-Bike Operational Instability

    Directory of Open Access Journals (Sweden)

    Ross H. Macmillan

    2017-05-01

    Full Text Available The stake-holders in the quad-bike (QB industry in Australia have failed to reach a satisfactory resolution of the present impasse that exists with respect to the causes and mitigation of the trauma suffered by riders due to QB instability. In an effort to provide purchasers with data enabling them to discriminate between safer and less safe machines, static longitudinal and lateral tests have been conducted by various interested parties; quasi-static lateral tests have also been conducted under some operational conditions. It is argued that while these static tests are valid, under many operating conditions QBs will not reach such unstable slopes due to poor traction. Further, these tests do not include the quasi-static and dynamic factors which also influence the processes associated with operational instability. For these reasons, the static tests do not provide an adequate basis for discrimination between safer and less safe machines.

  19. Nonlinear evolution of drift instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W.W.; Krommes, J.A.; Oberman, C.R.; Smith, R.A.

    1984-01-01

    The nonlinear evolution of collisionless drift instabilities in a shear-free magnetic field has been studied by means of gyrokinetic particle simulation as well as numerical integration of model mode-coupling equations. The purpose of the investigation is to identify relevant nonlinear mechanisms responsible for the steady-state drift wave fluctuations. It is found that the saturation of the instability is mainly caused by the nonlinear E x B convection of the resonant electrons and their associated velocity space nonlinearity. The latter also induces energy exchange between the competing modes, which, in turn, gives rise to enhanced diffusion. The nonlinear E x B convection of the ions, which contributes to the nonlinear frequency shift, is also an important ingredient for the saturation.

  20. Streaming Instabilities in Protoplanetary Disks

    CERN Document Server

    Youdin, A N; Youdin, Andrew N.; Goodman, Jeremy

    2004-01-01

    Interpenetrating streams of solids and gas in a Keplerian disk produce a local, linear instability. The two components mutually interact via aerodynamic drag, which generates radial drift and triggers unstable modes. The secular instability does not require self-gravity, yet it generates growing particle density perturbations that could seed planetesimal formation. Growth rates are slower than dynamical, but faster than radial drift, timescales. Growth rates, like streaming velocities, are maximized for marginal coupling (stopping times comparable dynamical times). Fastest growth occurs when the solid to gas density ratio is order unity and feedback is strongest. Curiously, growth is strongly suppressed when the densities are too nearly equal. The relation between background drift and wave properties is explained by analogy with Howard's semicircle theorem. The three-dimensional, two-fluid equations describe a sixth order (in the complex frequency) dispersion relation. A terminal velocity approximation allows...

  1. Instability of supersymmetric microstate geometries

    CERN Document Server

    Eperon, Felicity C; Santos, Jorge E

    2016-01-01

    We investigate the classical stability of supersymmetric, asymptotically flat, microstate geometries with five non-compact dimensions. Such geometries admit an "evanescent ergosurface": a timelike hypersurface of infinite redshift. On such a surface, there are null geodesics with zero energy relative to infinity. These geodesics are stably trapped in the potential well near the ergosurface. We present a heuristic argument indicating that this feature is likely to lead to a nonlinear instability of these solutions. We argue that the precursor of such an instability can be seen in the behaviour of linear perturbations: nonlinear stability would require that all linear perturbations decay sufficiently rapidly but the stable trapping implies that some linear perturbation decay very slowly. We study this in detail for the most symmetric microstate geometries. By constructing quasinormal modes of these geometries we show that generic linear perturbations decay slower than any inverse power of time.

  2. Buckling instability of squeezed droplets

    CERN Document Server

    Elfring, Gwynn J

    2015-01-01

    Motivated by recent experiments, we consider theoretically the compression of droplets pinned at the bottom on a surface of finite area. We show that if the droplet is sufficiently compressed at the top by a surface, it will always develop a shape instability at a critical compression. When the top surface is flat, the shape instability occurs precisely when the apparent contact angle of the droplet at the pinned surface is pi, regardless of the contact angle of the upper surface, reminiscent of past work on liquid bridges and sessile droplets as first observed by Plateau. After the critical compression, the droplet transitions from a symmetric to an asymmetric shape. The force required to deform the droplet peaks at the critical point then progressively decreases indicative of catastrophic buckling. We characterize the transition in droplet shape using illustrative examples in two dimensions followed by perturbative analysis as well as numerical simulation in three dimensions. When the upper surface is not f...

  3. Stretching Folding Instability and Nanoemulsions

    CERN Document Server

    Chan, Chon U

    2009-01-01

    Here we show a folding-stretching instability in a microfluidic flow focusing device using silicon oil (100cSt) and water. The fluid dynamics video demonstrates an oscillating thread of oil focused by two co-flowing streams of water. We show several high-speed sequences of these oscillations with 30,000 frames/s. Once the thread is decelerated in a slower moving pool downstream an instability sets in and water-in-oil droplets are formed. We reveal the details of the pinch-off with 500,000 frames/s. The pinch-off is so repeatable that complex droplet patterns emerge. Some of droplets are below the resolution limit, thus smaller than 1 micrometer in diameter.

  4. Instability of ties in compression

    DEFF Research Database (Denmark)

    Buch-Hansen, Thomas Cornelius

    2013-01-01

    Masonry cavity walls are loaded by wind pressure and vertical load from upper floors. These loads results in bending moments and compression forces in the ties connecting the outer and the inner wall in a cavity wall. Large cavity walls are furthermore loaded by differential movements from...... the temperature gradient between the outer and the inner wall, which results in critical increase of the bending moments in the ties. Since the ties are loaded by combined compression and moment forces, the loadbearing capacity is derived from instability equilibrium equations. Most of them are iterative, since......-connectors in cavity walls was developed. The method takes into account constraint conditions limiting the free length of the wall tie, and the instability in case of pure compression which gives an optimal load bearing capacity. The model is illustrated with examples from praxis....

  5. Instability of supersymmetric microstate geometries

    Energy Technology Data Exchange (ETDEWEB)

    Eperon, Felicity C.; Reall, Harvey S.; Santos, Jorge E. [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

    2016-10-07

    We investigate the classical stability of supersymmetric, asymptotically flat, microstate geometries with five non-compact dimensions. Such geometries admit an “evanescent ergosurface”: a timelike hypersurface of infinite redshift. On such a surface, there are null geodesics with zero energy relative to infinity. These geodesics are stably trapped in the potential well near the ergosurface. We present a heuristic argument indicating that this feature is likely to lead to a nonlinear instability of these solutions. We argue that the precursor of such an instability can be seen in the behaviour of linear perturbations: nonlinear stability would require that all linear perturbations decay sufficiently rapidly but the stable trapping implies that some linear perturbation decay very slowly. We study this in detail for the most symmetric microstate geometries. By constructing quasinormal modes of these geometries we show that generic linear perturbations decay slower than any inverse power of time.

  6. Modern management of patellar instability.

    Science.gov (United States)

    Rhee, Shin-Jae; Pavlou, George; Oakley, Jeremy; Barlow, David; Haddad, Farres

    2012-12-01

    Recurrent patellofemoral instability is a disabling condition, attributed to a variety of anatomical aetiologies. Trochlear dysplasia, patella alta, an increased tibial tubercle trochlear groove distance of greater than 20 mm and soft tissue abnormalities such as a torn medial patellofemoral ligament and inadequate vastus medialis obliquus are all factors to be considered. Management of this condition remains difficult and controversial and knowledge of the functional anatomy and biomechanics of the patellofemoral joint, a detailed history and clinical examination, and an accurate patient assessment are all imperative to formulate an appropriate management plan. Surgical treatment is based on the underlying anatomical pathology with an aim to restore normal patellofemoral kinematics. We summarise aspects of assessment, treatment and outcome of patellofemoral instability and propose an algorithm of treatment.

  7. Mechanical Instabilities of Biological Tubes

    CERN Document Server

    Hannezo, Edouard; Prost, Jacques; 10.1103/PhysRevLett.109.018101

    2012-01-01

    We study theoretically the shapes of biological tubes affected by various pathologies. When epithelial cells grow at an uncontrolled rate, the negative tension produced by their division provokes a buckling instability. Several shapes are investigated : varicose, enlarged, sinusoidal or sausage-like, all of which are found in pathologies of tracheal, renal tubes or arteries. The final shape depends crucially on the mechanical parameters of the tissues : Young modulus, wall-to-lumen ratio, homeostatic pressure. We argue that since tissues must be in quasistatic mechanical equilibrium, abnormal shapes convey information as to what causes the pathology. We calculate a phase diagram of tubular instabilities which could be a helpful guide for investigating the underlying genetic regulation.

  8. Fluctuations and Instability in Sedimentation

    KAUST Repository

    Guazzelli, Élisabeth

    2011-01-21

    This review concentrates on the fluctuations of the velocities of sedimenting spheres, and on the structural instability of a suspension of settling fibers. For many years, theoretical estimates and numerical simulations predicted the fluctuations of the velocities of spheres to increase with the size of the container, whereas experiments found no such variation. Two ideas have increased our understanding. First, the correlation length of the velocity fluctuations was found experimentally to be 20 interparticle separations. Second, in dilute suspensions, a vertical variation in the concentration due to the spreading of the front with the clear fluid can inhibit the velocity fluctuations. In a very dilute regime, a homogeneous suspension of fibers suffers a spontaneous instability in which fast descending fiber-rich columns are separated by rising fiber-sparse columns. In a semidilute regime, the settling is hindered, more so than for spheres. © 2011 by Annual Reviews. All rights reserved.

  9. Placing Marangoni instabilities under arrest

    CERN Document Server

    Bhamla, M Saad

    2016-01-01

    Soap bubbles occupy the rare position of delighting and fascinating both young children and scientific minds alike. Sir Isaac Newton, Joseph Plateau, Carlo Marangoni, and Pierre-Gilles de Gennes, not to mention countless others, have discovered remarkable results in optics, molecular forces and fluid dynamics from investigating this seemingly simple system. We present here a compilation of curiosity-driven experiments that systematically investigate the surface flows on a rising soap bubble. From childhood experience, we are familiar with the vibrant colors and mesmerizing display of chaotic flows on the surface of a soap bubble. These flows arise due to surface tension gradients, also known as Marangoni flows or instabilities. In Figure 1, we show the surprising effect of layering multiple instabilities on top of each other, highlighting that unexpected new phenomena are still waiting to be discovered, even in the simple soap bubble.

  10. Circulation in blast driven instabilities

    Science.gov (United States)

    Henry de Frahan, Marc; Johnsen, Eric

    2016-11-01

    Mixing in many natural phenomena (e.g. supernova collapse) and engineering applications (e.g. inertial confinement fusion) is often initiated through hydrodynamic instabilities. Explosions in these systems give rise to blast waves which can interact with perturbations at interfaces between different fluids. Blast waves are formed by a shock followed by a rarefaction. This wave profile leads to complex time histories of interface acceleration. In addition to the instabilities induced by the acceleration field, the rarefaction from the blast wave decompresses the material at the interface, further increasing the perturbation growth. After the passage of the wave, circulation circulation generated by the blast wave through baroclinic vorticity continues to act upon the interface. In this talk, we provide scaling laws for the circulation and amplitude growth induced by the blast wave. Numerical simulations of the multifluid Euler equations solved using a high-order accurate Discontinuous Galerkin method are used to validate the theoretical results.

  11. Report on the behalf of sustainable development and land planning commission of a bill aiming at prohibiting the exploration and exploitation on non conventional hydrocarbons, at abrogating exclusive search permits for non conventional hydrocarbon mines, and to ensure more transparency in the mining code; Rapport fait au nom de la Commission du Developpement Durable et de l'Amenagement du Territoire sur la proposition de loi, visant a interdire l'exploration et l'exploitation des hydrocarbures non conventionnels, a abroger les permis exclusifs de recherche de mines d'hydrocarbures non conventionnels et a assurer plus de transparence dans le code minier (n. 3690)

    Energy Technology Data Exchange (ETDEWEB)

    Chanteguet, J.P.

    2011-07-01

    In the first part of this report, the author (from the opposition party) outlines the opacity of the attribution procedure defined in the mining code for search permits, the lack of recognition of the citizen mobilization, and the inefficient and inapplicable character of the law of 2001 on the search for non conventional hydrocarbon mining sites. In the second part, the author outlines the need for an environment-friendly energy strategy, while recalling the necessity of protection of the environment when exploiting subsoils, the necessity of implementing an energy transition, and the necessity to reform the mining law. The discussion of the commission about the bill articles is reported

  12. MD 751: Train Instability Threshold

    CERN Document Server

    Carver, Lee Robert; Metral, Elias; Salvant, Benoit; Levens, Tom; Nisbet, David; Zobov, M; CERN. Geneva. ATS Department

    2016-01-01

    The purpose of this MD is to measure the octupole current thresholds for stability for a single bunch, and then make an immediate comparison (with the same operational settings) for a train of 72 bunches separated by 25ns. From theory, the expected thresholds should be similar. Any discrepancy between the two cases will be of great interest as it could indicate the presence of additional mechanisms that contribute to the instability threshold, for example electron cloud.

  13. Polygonal instabilities on interfacial vorticities

    CERN Document Server

    Labousse, Matthieu

    2015-01-01

    We report the results of a theoretical investigation of the stability of a toroidal vortex bound by an interface. Two distinct instability mechanisms are identified that rely on, respectively, surface tension and fluid inertia, either of which may prompt the transformation from a circular to a polygonal torus. Our results are discussed in the context of three experiments, a toroidal vortex ring, the hydraulic jump, and the hydraulic bump.

  14. Instability of colliding metastable strings

    Energy Technology Data Exchange (ETDEWEB)

    Hiramatsu, Takashi [Kyoto Univ. (Japan). Yukawa Inst. for Theoretical Physics; Eto, Minoru [Yamagata Univ. (Japan). Dept. of Physics; Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kobayashi, Tatsuo [Kyoto Univ. (Japan). Dept. of Physics; Ookouchi, Yutaka [Kyoto Univ. (Japan). Dept. of Physics; Kyoto Univ. (Japan). The Hakubi Center for Advanced Research

    2013-04-15

    We investigate the collision dynamics of two metastable strings which can be viewed as tube-like domain walls with winding numbers interpolating a false vacuum and a true vacuum. We find that depending on the relative angle and speed of two strings, instability of strings increases and the false vacuum is filled out by rapid expansion of the strings or of a remnant of the collision.

  15. Gravitational instabilities in astrophysical fluids

    Science.gov (United States)

    Tohline, Joel E.

    1990-01-01

    Over the past decade, the significant advancements that have been made in the development of computational tools and numerical techniques have allowed astrophysicists to begin to model accurately the nonlinear growth of gravitational instabilities in a variety of physical systems. The fragmentation or rotationally driven fission of dynamically evolving, self-gravitating ``drops and bubbles'' is now routinely modeled in full three-dimensional generality as we attempt to understand the behavior of protostellar clouds, rotating stars, galaxies, and even the primordial soup that defined the birth of the universe. A brief review is presented here of the general insights that have been gained from studies of this type, followed by a somewhat more detailed description of work, currently underway, that is designed to explain the process of binary star formation. A short video animation sequence, developed in conjunction with some of the research being reviewed, illustrates the basic-nature of the fission instability in rotating stars and of an instability that can arise in a massive disk that forms in a protostellar cloud.

  16. Microphysics of cosmic ray driven plasma instabilities

    CERN Document Server

    Bykov, A M; Malkov, M A; Osipov, S M

    2013-01-01

    Energetic nonthermal particles (cosmic rays, CRs) are accelerated in supernova remnants, relativistic jets and other astrophysical objects. The CR energy density is typically comparable with that of the thermal components and magnetic fields. In this review we discuss mechanisms of magnetic field amplification due to instabilities induced by CRs. We derive CR kinetic and magnetohydrodynamic equations that govern cosmic plasma systems comprising the thermal background plasma, comic rays and fluctuating magnetic fields to study CR-driven instabilities. Both resonant and non-resonant instabilities are reviewed, including the Bell short-wavelength instability, and the firehose instability. Special attention is paid to the longwavelength instabilities driven by the CR current and pressure gradient. The helicity production by the CR current-driven instabilities is discussed in connection with the dynamo mechanisms of cosmic magnetic field amplification.

  17. Manufacturing and characterization of ceramic pigment Zn{sub 1-x}Fe{sub x}Cr{sub 2}O{sub 4} by synthetic non conventional methods; Fabricacion y caracterizacion del pigmento ceramico Zn{sub 1-x}Fe{sub x}Cr{sub 2}O{sub 4} por metodos de sintesis no convencionales

    Energy Technology Data Exchange (ETDEWEB)

    Nieves, Leidy Johana Jaramillo; Baena, Oscar Jaime Restrepo, E-mail: ojrestre@unal.edu.co [Universidad Nacional de Colombia, Medellin (Colombia). Facultad de Minas

    2012-07-01

    The ceramic pigment with structure Zn{sub 1-x}Fe{sub x}Cr{sub 2}O{sub 4} (x = 0, 0.5, 1) was synthesized by non conventional methods of coprecipitation assisted by ultrasound and milling of high energy. This pigment was characterized by XRD, XRF, SEM, UV-VIS spectrophotometry and CIELab colorimetry. The aim of this work was studied two alternative methods to the traditional method of synthesis, evaluating the pigment properties, varying the stoichiometry, such as structure, composition, morphology and colorimetric coordinates. The results showed that is possible to obtain the desired crystalline structure at temperatures below 1000 ° C in both cases, also expected hues are obtained according to each stoichiometry, which shows the advantages of using methods non conventional when produce these pigments, since it has a higher controlling the composition, stoichiometry and is obtained at temperatures below compared with traditional ceramic method.

  18. 应用鱼骨图改善脑电仿生电刺激仪疗效的效果观察%Effect of fishbone diagram on improving curative effect of eeg bionic electrical stimulator

    Institute of Scientific and Technical Information of China (English)

    方丹灵; 金爱萍

    2015-01-01

    Objective:To improve the effect of eeg bionic electrical stimulator.Methods:From January to March 2014 into the standard 40 patients as control group,from April to June in 2014 patients included in the standard set for experimental group,two groups respectively by routine method,draw the fishbone diagram proposed rectification method after treatment using eeg bionic electrical stimulator,and the number of treatment time,every day,every time,period of treatment were the same.To evaluate the patients before and after the treatment respectively used MAS score method,the Barthel index,compared the re-sults.Results:The experimental group score of MAS and Barthel index were higher than the control group,the difference was statistically significant (P <0.05).Conclusion:The fishbone diagram is helpful to improve the therapeutic effect of brain dysfunction.%目的:提高脑电仿生电刺激仪疗效。方法:将2014年1~3月符合纳入标准的40例患者设为对照组,2014年4~6月符合纳入标准的40例患者设为试验组,对照组采用常规方法,试验组采用绘制鱼骨图后提出的整改方法使用脑电仿生电刺激仪进行治疗,两组每次治疗时间、每天治疗次数、疗程均相同。两组分别在治疗前后采用MAS评分法、Barthel指数对患者进行评估,比较结果。结果:试验组患者MAS评分、Barthel指数评分均高于对照组(P<0.05)。结论:鱼骨图有助于提高脑电仿生电刺激仪疗效。

  19. Modes of storage ring coherent instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.M.

    1986-12-01

    Longitudinal impedance in a beam and various modes of longitudinal coherent instabilities are discussed. The coasting beam coherent instability, microwave instability, and single-bunch longitudinal coherent instabilities are considered. The Vlasov equation is formulated, and a method of solving it is developed. The synchrotron modes are treated, which take the possible bunch shape distortion fully into consideration. A method of treating the synchrotron mode coupling in the case of a small bunch is discussed which takes advantage of the fact that only a few of the synchrotron modes can contribute in such a case. The effect of many bunches on the coherent motion of the beam and the longitudinal symmetric coupled bunch modes are discussed. The transverse impedance is then introduced, and the transverse coasting beam instability is discussed. Various bunched beam instabilities are discussed, including both single bunch instabilities and coupled bunch instabilities. The Vlasov equation for transverse as well as longitudinal motion of particles is introduced as well as a method of solving it within a linear approximation. Head-tail modes and short bunch instabilities and strong coupling instabilities in the long bunch case are covered. (LEW)

  20. On the Application of Fishbone Diagram Analysis in Tailings Reservoir Dam Break%鱼刺图评价法在尾矿库溃坝事故中的应用

    Institute of Scientific and Technical Information of China (English)

    吴令; 周波

    2012-01-01

    根据尾矿库现场危险、有害因素辨识结果,概括出尾矿库溃坝事故发主的四个主要因素:施工、排洪、渗流和管理,对主要因素的原因进行归纳、分析,找出了重要原因,应用鱼刺图法评价得到了尾矿库溃坝事故的危险程度和等级,提出了防止这类事故发生的重点安全对策措施,提高了尾矿库的安全管理程度.%According to the identification results of dangerous and harmful factors identification in the tailings reservoir site, the four main factors: construction, drainage flood, seepage flow and management are summarized in the dam-break accident. Through induction and analysis, found out the main reasons. The risk degree and level of the tailings dam-break accident are got by using the fishbone diagram, and some safety measures are put forward. Tailing dam safety management level has been improved.

  1. 基于鱼骨图和AHP的产业集群知识创新能力影响因素研究%Research on Influence Factor of Industrial Clusters Knowledge Innovation Ability Based on Fishbone Diagram and AHP

    Institute of Scientific and Technical Information of China (English)

    谈甄; 储节旺; 李丽娟

    2012-01-01

    This paper brings forward the approach of combining quantitative with qualitative to make analysis the industrial clusters knowledge innovation ability influence factors. Firstly, we use the approach of fishbone diagram tO tease out industrial clusters knowledge innovation ability influence factors, then importing them into the model of AHP. Through subjective evaluation and experts evaluation we constructed the determine matrix, Calculated relative to the target of various factors of the importance of weight. Finally, by sequencing to identify the key influencing factors, and to improve the knowledge innovation capability of industrial clusters offer some constructive advice.%采用定量和定性相结合的方法分析产业集群知识创新能力的影响因素,首先用鱼骨图法梳理出产业集群知识创新能力影响因素,然后导入AHP模型中,通过主观评价、专家评判和综合分析构造判断矩阵,计算各个影响因素相对于目标问题的重要性权重,最后通过排序找出关键影响因素,并为提高产业集群知识创新能力提供一些建设性意见。

  2. 基于鱼骨图的艾滋病预防策略影响因素分析%The influential factors of HIV/AIDS prevention strategy based on fishbone diagram

    Institute of Scientific and Technical Information of China (English)

    姜袁; 地里夏提·亚合甫; 戴江红

    2015-01-01

    Using the fishbone diagram analysis method and existing research results and policies,the author analyzed influential factors of HIV /AIDS prevention strategy from the perspective of people,technology,policy,so-ciety and environment,supervision and assessment,economic,ethical etc,to provide support and gist for the AIDS prevention strategy,and contain and reverse the spread of HIV /AIDS,so as to guarantee the achievement of the mil-lennium development goals.%利用鱼骨图分析法,综合现有科学研究结果及相关政策,从人群、技术、政策、社会、环境、监督考核、经济、伦理等方面综合分析艾滋病预防策略影响因素,为艾滋病预防策略的实施、开展提供依据和支持,为遏制并扭转 HIV 感染/艾滋病的蔓延,实现千年发展目标提供有力保障。

  3. Compressor instability with integral methods

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Y.K. Eddie [Nanyang Technological Univ., Singapore (Singapore). School of Mechanical and Aerospace Engineering; Liu, Ningyu [Singapore National Univ. (Singapore). Dept. of Mechanical Engineering

    2007-07-01

    ''Compressor Instability with Integral Methods'' is a book, to bring together the quick integral approaches and advances in the field for the prediction of stall and surge problem in compressor. This book is useful for people involved in the flow analysis, design and testing of rotating machinery. For students, it can be used as a specialized topic of senior undergraduate or graduate study. The book can also be served as a self-study material to those who keen to acquire this knowledge. In brief, this book focuses on the numerical/computational analysis for the effect of distorted inlet flow propagation on the rotating stall and surge in axial compressors. It gains insight into the basic phenomena controlling these flow instabilities, and reveals the influence of inlet parameters on rotating stall and surge. The book starts from the confirmation and application of Kim et al's integral method and then follows by a development to this method through the proposing and applying a critical distortion line. This line is applied successfully on the stall prediction of in-flight compressor due to flaming of refueling leakage near inlet, a typical real and interesting example of compressor stall and surge operation. Further, after a parametric study on the integral method and the distorted flow field of compressor using Taguchi method, a novel integral method is formulated using more appropriate and practical airfoil characteristics, with a less assumptions needed for derivation. Finally, as an extended work, the famous Greitzer's instability flow model, the well-known B-parameter model applied for analyzing the stall and surge characteristics, is studied parametrically using Taguchi method. (orig.)

  4. Bathtub vortex induced by instability

    Science.gov (United States)

    Mizushima, Jiro; Abe, Kazuki; Yokoyama, Naoto

    2014-10-01

    The driving mechanism and the swirl direction of the bathtub vortex are investigated by the linear stability analysis of the no-vortex flow as well as numerical simulations. We find that only systems having plane symmetries with respect to vertical planes deserve research for the swirl direction. The bathtub vortex appearing in a vessel with a rectangular cross section having a drain hole at the center of the bottom is proved to be induced by instability when the flow rate exceeds a threshold. The Coriolis force is capable of determining the swirl direction to be cyclonic.

  5. Spatiotemporal chaos involving wave instability

    Science.gov (United States)

    Berenstein, Igal; Carballido-Landeira, Jorge

    2017-01-01

    In this paper, we investigate pattern formation in a model of a reaction confined in a microemulsion, in a regime where both Turing and wave instability occur. In one-dimensional systems, the pattern corresponds to spatiotemporal intermittency where the behavior of the systems alternates in both time and space between stationary Turing patterns and traveling waves. In two-dimensional systems, the behavior initially may correspond to Turing patterns, which then turn into wave patterns. The resulting pattern also corresponds to a chaotic state, where the system alternates in both space and time between standing wave patterns and traveling waves, and the local dynamics may show vanishing amplitude of the variables.

  6. Nonlinear Instability of Liquid Layers.

    Science.gov (United States)

    Newhouse, Lori Ann

    The nonlinear instability of two superposed viscous liquid layers in planar and axisymmetric configurations is investigated. In the planar configuration, the light layer fluid is bounded below by a wall and above by a heavy semiinfinite fluid. Gravity drives the instability. In the first axisymmetric configuration, the layer is confined between a cylindrical wall and a core of another fluid. In the second, a thread is suspended in an infinite fluid. Surface tension forces drive the instability in the axisymmetric configurations. The nonlinear evolution of the fluid-fluid interface is computed for layers of arbitrary thickness when their dynamics are fully coupled to those of the second fluid. Under the assumption of creeping flow, the flow field is represented by an interfacial distribution of Green's functions. A Fredholm integral equation of the second kind for the strength of the distribution is derived and then solved using an iterative technique. The Green's functions produce flow fields which are periodic in the direction parallel to the wall and have zero velocity on the wall. For small and moderate surface tension, planar layers evolve into a periodic array of viscous plumes which penetrate into the overlying fluid. The morphology of the plumes depends on the surface tension and the ratio of the fluid viscosities. As the viscosity of the layer increases, the plumes change from a well defined drop on top of a narrow stem to a compact column of rising fluid. The capillary instability of cylindrical interfaces and interfaces in which the core thickness varies in the axial direction are investigated. In both the unbounded and wall bounded configurations, the core evolves into a periodic array of elongated fluid drops connected by thin, almost cylindrical fluid links. The characteristics of the drop-link structure depend on the core thickness, the ratio of the core radius to the wall radius, and the ratio of the fluid viscosities. The factors controlling the

  7. Mode-locking via dissipative Faraday instability

    Science.gov (United States)

    Tarasov, Nikita; Perego, Auro M.; Churkin, Dmitry V.; Staliunas, Kestutis; Turitsyn, Sergei K.

    2016-08-01

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system--spectrally dependent losses--achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering.

  8. Transverse Instabilities in the Fermilab Recycler

    Energy Technology Data Exchange (ETDEWEB)

    Prost, L.R.; Burov, A.; Shemyakin, A.; Bhat, C.M.; Crisp, J.; Eddy, N.; /Fermilab

    2011-07-01

    Transverse instabilities of the antiproton beam have been observed in the Recycler ring soon after its commissioning. After installation of transverse dampers, the threshold for the instability limit increased significantly but the instability is still found to limit the brightness of the antiprotons extracted from the Recycler for Tevatron shots. In this paper, we describe observations of the instabilities during the extraction process as well as during dedicated studies. The measured instability threshold phase density agrees with the prediction of the rigid beam model within a factor of 2. Also, we conclude that the instability threshold can be significantly lowered for a bunch contained in a narrow and shallow potential well due to effective exclusion of the longitudinal tails from Landau damping.

  9. Optimal excitation of two dimensional Holmboe instabilities

    CERN Document Server

    Constantinou, Navid C

    2010-01-01

    Highly stratified shear layers are rendered unstable even at high stratifications by Holmboe instabilities when the density stratification is concentrated in a small region of the shear layer. These instabilities may cause mixing in highly stratified environments. However these instabilities occur in tongues for a limited range of parameters. We perform Generalized Stability analysis of the two dimensional perturbation dynamics of an inviscid Boussinesq stratified shear layer and show that Holmboe instabilities at high Richardson numbers can be excited by their adjoints at amplitudes that are orders of magnitude larger than by introducing initially the unstable mode itself. We also determine the optimal growth that obtains for parameters for which there is no instability. We find that there is potential for large transient growth regardless of whether the background flow is exponentially stable or not and that the characteristic structure of the Holmboe instability asymptotically emerges for parameter values ...

  10. Mode-locking via dissipative Faraday instability.

    Science.gov (United States)

    Tarasov, Nikita; Perego, Auro M; Churkin, Dmitry V; Staliunas, Kestutis; Turitsyn, Sergei K

    2016-08-09

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system-spectrally dependent losses-achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering.

  11. Instabilities and transition in boundary layers

    Indian Academy of Sciences (India)

    N Vinod; Rama Govindarajan

    2005-03-01

    Some recent developments in boundary layer instabilities and transition are reviewed. Background disturbance levels determine the instability mechanism that ultimately leads to turbulence. At low noise levels, the traditional Tollmien–Schlichting route is followed, while at high levels, a `by-pass' route is more likely. Our recent work shows that spot birth is related to the pattern of secondary instability in either route.

  12. Beam Instabilities in the Scale Free Regime

    CERN Document Server

    Folli, Viola; Conti, Claudio; 10.1103/PhysRevLett.108.033901

    2012-01-01

    The instabilities arising in a one-dimensional beam sustained by the diffusive photorefractive nonlinearity in out-of-equilibrium ferroelectrics are theoretically and numerically investigated. In the "scale-free model", in striking contrast with the well-known spatial modulational instability, two different beam instabilities dominate: a defocusing and a fragmenting process. Both are independent of the beam power and are not associated to any specific periodic pattern.

  13. Electron proton instability in the CSNS ring

    Institute of Scientific and Technical Information of China (English)

    WANG Na; QIN Qing; LIU Yu-Dong

    2009-01-01

    The electron proton(e-p)instability has been observed in many proton accelerators.It will induce transverse beam size blow-up,cause beam loss and restrict the machine performance.Much research work has been done on the causes,dynamics and cures of this instability.A simulation code is developed to study the e-p instability in the ring of the China Spallation Neutron Source(CSNS).

  14. [Cervical spine instability in the surgical patient].

    Science.gov (United States)

    Barbeito, A; Guerri-Guttenberg, R A

    2014-03-01

    Many congenital and acquired diseases, including trauma, may result in cervical spine instability. Given that airway management is closely related to the movement of the cervical spine, it is important that the anesthesiologist has detailed knowledge of the anatomy, the mechanisms of cervical spine instability, and of the effects that the different airway maneuvers have on the cervical spine. We first review the normal anatomy and biomechanics of the cervical spine in the context of airway management and the concept of cervical spine instability. In the second part, we review the protocols for the management of cervical spine instability in trauma victims and some of the airway management options for these patients.

  15. Two-Fluid Interface Instability Being Studied

    Science.gov (United States)

    Niederhaus, Charles E.

    2003-01-01

    The interface between two fluids of different density can experience instability when gravity acts normal to the surface. The relatively well known Rayleigh-Taylor (RT) instability results when the gravity is constant with a heavy fluid over a light fluid. An impulsive acceleration applied to the fluids results in the Richtmyer-Meshkov (RM) instability. The RM instability occurs regardless of the relative orientation of the heavy and light fluids. In many systems, the passing of a shock wave through the interface provides the impulsive acceleration. Both the RT and RM instabilities result in mixing at the interface. These instabilities arise in a diverse array of circumstances, including supernovas, oceans, supersonic combustion, and inertial confinement fusion (ICF). The area with the greatest current interest in RT and RM instabilities is ICF, which is an attempt to produce fusion energy for nuclear reactors from BB-sized pellets of deuterium and tritium. In the ICF experiments conducted so far, RM and RT instabilities have prevented the generation of net-positive energy. The $4 billion National Ignition Facility at Lawrence Livermore National Laboratory is being constructed to study these instabilities and to attempt to achieve net-positive yield in an ICF experiment.

  16. Aeroelastic instability problems for wind turbines

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig

    2007-01-01

    This paper deals with the aeroelostic instabilities that have occurred and may still occur for modem commercial wind turbines: stall-induced vibrations for stall-turbines, and classical flutter for pitch-regulated turbines. A review of previous works is combined with derivations of analytical...... stiffness and chordwise position of the center of gravity along the blades are the main parameters for flutter. These instability characteristics are exemplified by aeroelastic stability analyses of different wind turbines. The review of each aeroelastic instability ends with a list of current research...... issues that represent unsolved aeroelostic instability problems for wind turbines. Copyright (c) 2007 John Wiley & Sons, Ltd....

  17. Review of two-phase instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Han Ok; Seo, Han Ok; Kang, Hyung Suk; Cho, Bong Hyun; Lee, Doo Jeong

    1997-06-01

    KAERI is carrying out a development of the design for a new type of integral reactors. The once-through helical steam generator is important design features. The study on designs and operating conditions which prevent flow instability should precede the introduction of one-through steam generator. Experiments are currently scheduled to understand two-phase instability, evaluate the effect of each design parameter on the critical point, and determine proper inlet throttling for the prevention of instability. This report covers general two-phase instability with review of existing studies on this topics. The general classification of two phase flow instability and the characteristics of each type of instability are first described. Special attention is paid to BWR core flow instability and once-through steam generator instability. The reactivity feedback and the effect of system parameters are treated mainly for BWR. With relation to once-through steam generators, the characteristics of convective heating and dryout point oscillation are first investigated and then the existing experimental studies are summarized. Finally chapter summarized the proposed correlations for instability boundary conditions. (author). 231 refs., 5 tabs., 47 figs

  18. Systems and methods for controlling flame instability

    KAUST Repository

    Cha, Min Suk

    2016-07-21

    A system (62) for controlling flame instability comprising: a nozzle (66) coupled to a fuel supply line (70), an insulation housing (74) coupled to the nozzle, a combustor (78) coupled to the nozzle via the insulation housing, where the combustor is grounded (80), a pressure sensor (82) coupled to the combustor and configured to detect pressure in the combustor, and an instability controlling assembly coupled to the pressure sensor and to an alternating current power supply (86), where, the instability controlling assembly can control flame instability of a flame in the system based on pressure detected by the pressure sensor.

  19. Instabilities of flows and transition to turbulence

    CERN Document Server

    Sengupta, Tapan K

    2012-01-01

    Introduction to Instability and TransitionIntroductionWhat Is Instability?Temporal and Spatial InstabilitySome Instability MechanismsComputing Transitional and Turbulent FlowsFluid Dynamical EquationsSome Equilibrium Solutions of the Basic EquationBoundary Layer TheoryControl Volume Analysis of Boundary LayersNumerical Solution of the Thin Shear Layer (TSL) EquationLaminar Mixing LayerPlane Laminar JetIssues of Computing Space-Time Dependent FlowsWave Interaction: Group Velocity and Energy FluxIssues of Space-Time Scale Resolution of FlowsTemporal Scales in Turbulent FlowsComputing Time-Averag

  20. The Chemistry of Beer Instability

    Science.gov (United States)

    Stewart, Graham G.

    2004-07-01

    Compared to most other alcoholic beverages, beer is unique because it is unstable when in the final package. This instability can be divided into biological and nonbiological instability. Nonbiological stability of beer involves a wide range of chemical processes and can be considered in a number of categories: physical, flavor, light, foam, and gushing. It is the balance between flavanoid polyphenols (tannoids) and sensitive proteins that specifically combine with polyphenols to form haze that largely dictates physical stability. The flavor stability of beer primarily depends on the oxygen concentration of packaged beer but is influenced by all stages of the brewing process. Foam stability in a glass of beer reflects the quality of the beverage. The backbone of foam is hydrophobic polypeptides. Novel brewing processes such as high-gravity brewing result in a disproportionate loss of these polypeptides and have a negative effect on the foam stability of the resulting beer. Beer is light sensitive, especially in the 350 500 nm range. Beer exposed to this wavelength range in clear or green glass containers quickly develop nauseous skunky-like off-flavors resulting from the formation of 3-methyl-2-butene-1-thiol. Methods of enhancing all of these types of beer stability are discussed.

  1. Option price and market instability

    Science.gov (United States)

    Baaquie, Belal E.; Yu, Miao

    2017-04-01

    An option pricing formula, for which the price of an option depends on both the value of the underlying security as well as the velocity of the security, has been proposed in Baaquie and Yang (2014). The FX (foreign exchange) options price was empirically studied in Baaquie et al., (2014), and it was found that the model in general provides an excellent fit for all strike prices with a fixed model parameters-unlike the Black-Scholes option price Hull and White (1987) that requires the empirically determined implied volatility surface to fit the option data. The option price proposed in Baaquie and Cao Yang (2014) did not fit the data during the crisis of 2007-2008. We make a hypothesis that the failure of the option price to fit data is an indication of the market's large deviation from its near equilibrium behavior due to the market's instability. Furthermore, our indicator of market's instability is shown to be more accurate than the option's observed volatility. The market prices of the FX option for various currencies are studied in the light of our hypothesis.

  2. Cosmic Rays and Radiative Instabilities

    CERN Document Server

    Hartquist, T W; Falle, S A E G; Pittard, J M; Van Loo, S

    2011-01-01

    In the absence of magnetic fields and cosmic rays, radiative cooling laws with a range of dependences on temperature affect the stability of interstellar gas. For about four and a half decades, astrophysicists have recognised the importance of the thermal instablity for the formation of clouds in the interstellar medium. Even in the past several years, many papers have concerned the role of the thermal instability in the production of molecular clouds. About three and a half decades ago, astrophysicists investigating radiative shocks noticed that for many cooling laws such shocks are unstable. Attempts to address the effects of cosmic rays on the stablity of radiative media that are initially uniform or that have just passed through shocks have been made. The simplest approach to such studies involves the assumption that the cosmic rays behave as a fluid. Work based on such an approach is described. Cosmic rays have no effect on the stability of initially uniform, static media with respect to isobaric perturb...

  3. Visco-Resistive Plasmoid Instability

    CERN Document Server

    Comisso, Luca

    2016-01-01

    The plasmoid instability in visco-resistive current sheets is analyzed in both the linear and nonlinear regimes. The linear growth rate and the wavenumber are found to scale as $S^{1/4} {\\left( {1 + {P_m}} \\right)}^{-5/8}$ and $S^{3/8} {\\left( {1 + {P_m}} \\right)}^{-3/16}$ with respect to the Lundquist number $S$ and the magnetic Prandtl number $P_m$. Furthermore, the linear layer width is shown to scale as $S^{-1/8} {(1+P_m)}^{1/16}$. The growth of the plasmoids slows down from an exponential growth to an algebraic growth when they enter into the nonlinear regime. In particular, the time-scale of the nonlinear growth of the plasmoids is found to be $\\tau_{NL} \\sim S^{-3/16} {(1 + P_m)^{19/32}}{\\tau _{A,L}}$. The nonlinear growth of the plasmoids is radically different from the linear one and it is shown to be essential to understand the global current sheet disruption. It is also discussed how the plasmoid instability enables fast magnetic reconnection in visco-resistive plasmas. In particular, it is shown t...

  4. Combustion instability modeling and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States)] [and others

    1995-10-01

    It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. Clearly, the key to successful gas turbine development is based on understanding the effects of geometry and operating conditions on combustion instability, emissions (including UHC, CO and NO{sub x}) and performance. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors.

  5. Interfacial instabilities in vibrated fluids

    Science.gov (United States)

    Porter, Jeff; Laverón-Simavilla, Ana; Tinao Perez-Miravete, Ignacio; Fernandez Fraile, Jose Javier

    2016-07-01

    Vibrations induce a range of different interfacial phenomena in fluid systems depending on the frequency and orientation of the forcing. With gravity, (large) interfaces are approximately flat and there is a qualitative difference between vertical and horizontal forcing. Sufficient vertical forcing produces subharmonic standing waves (Faraday waves) that extend over the whole interface. Horizontal forcing can excite both localized and extended interfacial phenomena. The vibrating solid boundaries act as wavemakers to excite traveling waves (or sloshing modes at low frequencies) but they also drive evanescent bulk modes whose oscillatory pressure gradient can parametrically excite subharmonic surface waves like cross-waves. Depending on the magnitude of the damping and the aspect ratio of the container, these locally generated surfaces waves may interact in the interior resulting in temporal modulation and other complex dynamics. In the case where the interface separates two fluids of different density in, for example, a rectangular container, the mass transfer due to vertical motion near the endwalls requires a counterflow in the interior region that can lead to a Kelvin-Helmholtz type instability and a ``frozen wave" pattern. In microgravity, the dominance of surface forces favors non-flat equilibrium configurations and the distinction between vertical and horizontal applied forcing can be lost. Hysteresis and multiplicity of solutions are more common, especially in non-wetting systems where disconnected (partial) volumes of fluid can be established. Furthermore, the vibrational field contributes a dynamic pressure term that competes with surface tension to select the (time averaged) shape of the surface. These new (quasi-static) surface configurations, known as vibroequilibria, can differ substantially from the hydrostatic state. There is a tendency for the interface to orient perpendicular to the vibrational axis and, in some cases, a bulge or cavity is induced

  6. On the descriptions of beam instabilities

    CERN Document Server

    Maillard, Antoine

    2016-01-01

    We investigate two interesting features of beam instabilities in accelerators : First, we provide the equivalence between two models to describe transverse instabilities, the circulant matrix model (based on a longitudinal phase space discretization) and the Vlasov formalism. Secondly, we show how to derive dispersion integrals for transverse detuning effects in the Vlasov formalism, thus allowing for Landau damping mechanism.

  7. Parametric Instability: An Elementary Demonstration and Discussion.

    Science.gov (United States)

    Case, William

    1980-01-01

    Discusses parametric oscillators and parametric instability. A simple, easy-to-construct system which exhibits parametric instability is presented. The two lowest-order resonances are described and analyzed in detail. The analysis stresses the physical and intuitive aspects of the problem. (Author/HM)

  8. Energetic particle instabilities in fusion plasmas

    NARCIS (Netherlands)

    Sharapov, S. E.; Alper, B.; Berk, H. L.; Borba, D. N.; Breizman, B. N.; Challis, C. D.; Classen, I.G.J.; Edlund, E. M.; Eriksson, J.; Fasoli, A.; Fredrickson, E. D.; Fu, G. Y.; Garcia-Munoz, M.; Gassner, T.; Ghantous, K.; Goloborodko, V.; Gorelenkov, N. N.; Gryaznevich, M. P.; Hacquin, S.; Heidbrink, W. W.; Hellesen, C.; Kiptily, V. G.; Kramer, G. J.; Lauber, P.; Lilley, M. K.; Lisak, M.; Nabais, F.; Nazikian, R.; Nyqvist, R.; Osakabe, M.; C. Perez von Thun,; Pinches, S. D.; Podesta, M.; Porkolab, M.; Shinohara, K.; Schoepf, K.; Todo, Y.; Toi, K.; VanZeeland, M. A.; Voitsekhovich, I.; White, R. B.; Yavorskij, V.; ITPA EP TG Contributors,; JET-EFDA Contributors,

    2013-01-01

    Remarkable progress has been made in diagnosing energetic particle instabilities on present-day machines and in establishing a theoretical framework for describing them. This overview describes the much improved diagnostics of Alfvén instabilities and modelling tools developed world-wide, and discus

  9. Cultural diversity, economic development and societal instability

    Science.gov (United States)

    Nettle, D.; Grace, J.B.; Choisy, M.; Cornell, H.V.; Guegan, J.-F.; Hochberg, M.E.

    2007-01-01

    Background. Social scientists have suggested that cultural diversity in a nation leads to societal instability. However, societal instability may be affected not only by within-nation on ?? diversity, but also diversity between a nation and its neighbours or ?? diversity. It is also necessary to distinguish different domains of diversity, namely linguistic, ethnic and religious, and to distinguish between the direct effects of diversity on societal instability, and effects that are mediated by economic conditions. Methodology/Principal Findings. We assembled a large cross-national dataset with information on ?? and ?? cultural diversity, economic conditions, and indices of societal instability. Structural equation modeling was used to evaluate the direct and indirect effects of cultural diversity on economics and societal stability. Results show that different type and domains of diversity have interacting effects. As previously documented, linguistic ?? diversity has a negative effect on economic performance, and we show that it is largely through this economic mechanism that it affects societal instability. For ?? diversity, the higher the linguistic diversity among nations in a region, the less stable the nation. But, religious ?? diversity has the opposite effect, reducing instability, particularly in the presence of high linguistic diversity. Conclusions. Within-nation linguistic diversity is associated with reduced economic performance, which, in turn, increases societal instability. Nations which differ linguistically from their neighbors are also less stable. However, religious diversity between, neighboring nations has the opposite effect, decreasing societal instability.

  10. Magnetic resonance imaging in glenohumeral instability

    Science.gov (United States)

    Jana, Manisha; Gamanagatti, Shivanand

    2011-01-01

    The glenohumeral joint is the most commonly dislocated joint of the body and anterior instability is the most common type of shoulder instability. Magnetic resonance (MR) imaging, and more recently, MR arthrography, have become the essential investigation modalities of glenohumeral instability, especially for pre-procedure evaluation before arthroscopic surgery. Injuries associated with glenohumeral instability are variable, and can involve the bones, the labor-ligamentous components, or the rotator cuff. Anterior instability is associated with injuries of the anterior labrum and the anterior band of the inferior glenohumeral ligament, in the form of Bankart lesion and its variants; whereas posterior instability is associated with reverse Bankart and reverse Hill-Sachs lesion. Multidirectional instability often has no labral pathology on imaging but shows specific osseous changes such as increased chondrolabral retroversion. This article reviews the relevant anatomy in brief, the MR imaging technique and the arthrographic technique, and describes the MR findings in each type of instability as well as common imaging pitfalls. PMID:22007285

  11. Hydrodynamic Instabilities in Rotating Fluids

    Institute of Scientific and Technical Information of China (English)

    KarlBuehler

    2000-01-01

    Rotating flow systems are often used to study stability phenomena and structure developments.The closed spherical gap prblem is generalized into an open flow system by superimposing a mass flux in meridional direction.The basic solutions at low Reynolds numbers are described by analytical methods.The nonlinear supercritical solutions are simulated numerically and realized in experiments.Novel steady and time-dependent modes of flows are obtained.The extensive results concern the stability behaviour.non-uniqueness of supercritical solutions,symmetry behaviour and transitions between steady and time-dependent solutions.The experimental investigations concern the visualization of the various instabilities and the quatitative description of the flow structures including the laminar-turbulent transition.A Comparison between theoretical and experimental results shows good agreement within the limit of rotational symmetric solutions from the theory.

  12. Transient spirals as superposed instabilities

    CERN Document Server

    Sellwood, J A

    2014-01-01

    We present evidence that recurrent spiral activity, long manifested in simulations of disk galaxies, results from the super-position of a few transient spiral modes. Each mode lasts between five and ten rotations at its corotation radius where its amplitude is greatest. The scattering of stars as each wave decays takes place over narrow ranges of angular momentum, causing abrupt changes to the impedance of the disk to subsequent traveling waves. Partial reflections of waves at these newly created features, allows new standing-wave instabilities to appear that saturate and decay in their turn, scattering particles at new locations, creating a recurring cycle. The spiral activity causes the general level of random motion to rise, gradually decreasing the ability of the disk to support further activity unless the disk contains a dissipative gas component from which stars form on near-circular orbits. We also show that this interpretation is consistent with the behavior reported in other recent simulations with l...

  13. Gravitational Instability of a Kink

    CERN Document Server

    Barreto, W; Lehner, L; Winicour, J

    1996-01-01

    We study the equilibria of a self-gravitating scalar field in the region outside a reflecting barrier. By introducing a potential difference between the barrier and infinity, we create a kink which cannot decay to a zero energy state. In the realm of small amplitude, the kink decays to a known static solution of the Einstein-Klein-Gordon equation. However, for larger kinks the static equilibria are degenerate, forming a system with two energy levels. The upper level is unstable and, under small perturbations, decays to the lower energy stable equilibrium. Under large perturbations, the unstable upper level undergoes collapse to a black hole. The equilibrium of the system provides a remarkably simple and beautiful illustration of a turning point instability.

  14. Mapping Instabilities in Polymer Friction

    Science.gov (United States)

    Rand, Charles; Crosby, Alfred

    2005-03-01

    Schallamach waves are instabilities that occur as interfaces between a soft elastomer and rigid surface slide past each other.(1) The presence of Schallamach waves can lead to drastic changes in frictional properties. Although the occurrence of Schallamach waves has been studied for the past several decades, a general map relating fundamental material properties, geometry, and operating conditions (i.e. speed and temperature) has not been established. Using a combinatorial approach, we illustrate the role of modulus, testing velocity and surface energetics of crosslinked poly(dimethyl siloxane) on the generation Schallamach waves. This knowledge will be used with polymer patterning processes to fabricate responsive coatings for applications such as anti-fouling coatings. (1)Schallamach, A.;Wear 1971,17, 301-312.

  15. Secondary instability in boundary-layer flows

    Science.gov (United States)

    Nayfeh, A. H.; Bozatli, A. N.

    1979-01-01

    The stability of a secondary Tollmien-Schlichting wave, whose wavenumber and frequency are nearly one half those of a fundamental Tollmien-Schlichting instability wave is analyzed using the method of multiple scales. Under these conditions, the fundamental wave acts as a parametric exciter for the secondary wave. The results show that the amplitude of the fundamental wave must exceed a critical value to trigger this parametric instability. This value is proportional to a detuning parameter which is the real part of k - 2K, where k and K are the wavenumbers of the fundamental and its subharmonic, respectively. For Blasius flow, the critical amplitude is approximately 29% of the mean flow, and hence many other secondary instabilities take place before this parametric instability becomes significant. For other flows where the detuning parameter is small, such as free-shear layer flows, the critical amplitude can be small, thus the parametric instability might play a greater role.

  16. Taylor instability in rhyolite lava flows

    Science.gov (United States)

    Baum, B. A.; Krantz, W. B.; Fink, J. H.; Dickinson, R. E.

    1989-01-01

    A refined Taylor instability model is developed to describe the surface morphology of rhyolite lava flows. The effect of the downslope flow of the lava on the structures resulting from the Taylor instability mechanism is considered. Squire's (1933) transformation is developed for this flow in order to extend the results to three-dimensional modes. This permits assessing why ridges thought to arise from the Taylor instability mechanism are preferentially oriented transverse to the direction of lava flow. Measured diapir and ridge spacings for the Little and Big Glass Mountain rhyolite flows in northern California are used in conjunction with the model in order to explore the implications of the Taylor instability for flow emplacement. The model suggests additional lava flow features that can be measured in order to test whether the Taylor instability mechanism has influenced the flows surface morphology.

  17. Whipping Instabilities in Electrified Liquid Jets

    CERN Document Server

    Marin, Alvaro G; Loscertales, Ignacio G; Barrero, Antonio

    2008-01-01

    A liquid jet may develop different types of instabilities, like the so-called Rayleigh-Plateau instability, which breaks the jet into droplets. However, another type of instabilities may appear when we electrify a liquid jet and induce some charge at his surface. Among them, the most common is the so-called Whipping Instability, which is characterized by violent and fast lashes of the jet. In the submitted fluid dynamic video(see http://hdl.handle.net/1813/11422), we will show an unstable charged glycerine jet in a dielectric liquid bath, which permits an enhanced visualization of the instability. For this reason, it is probably the first time that these phenomena are visualized with enough clarity to analyze features as the effect of the feeding liquid flow rate through the jet or as the surprising spontaneous stabilization at some critical distance to the ground electrode.

  18. 3-D nonlinear evolution of MHD instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, G.; Hicks, H. R.; Wooten, J. W.

    1977-03-01

    The nonlinear evolution of ideal MHD internal instabilities is investigated in straight cylindrical geometry by means of a 3-D initial-value computer code. These instabilities are characterized by pairs of velocity vortex cells rolling off each other and helically twisted down the plasma column. The cells persist until the poloidal velocity saturates at a few tenths of the Alfven velocity. The nonlinear phase is characterized by convection around these essentially fixed vortex cells. For example, the initially centrally peaked temperature profile is convected out and around to form an annulus of high temperature surrounding a small region of lower temperature. Weak, centrally localized instabilities do not alter the edge of the plasma. Strong, large-scale instabilities, resulting from a stronger longitudinal equilibrium current, drive the plasma against the wall. After three examples of instability are analyzed in detail, the numerical methods and their verification are discussed.

  19. Tensile Instability in a Thick Elastic Body

    Science.gov (United States)

    Overvelde, Johannes T. B.; Dykstra, David M. J.; de Rooij, Rijk; Weaver, James; Bertoldi, Katia

    2016-08-01

    A range of instabilities can occur in soft bodies that undergo large deformation. While most of them arise under compressive forces, it has previously been shown analytically that a tensile instability can occur in an elastic block subjected to equitriaxial tension. Guided by this result, we conducted centimeter-scale experiments on thick elastomeric samples under generalized plane strain conditions and observed for the first time this elastic tensile instability. We found that equibiaxial stretching leads to the formation of a wavy pattern, as regions of the sample alternatively flatten and extend in the out-of-plane direction. Our work uncovers a new type of instability that can be triggered in elastic bodies, enlarging the design space for smart structures that harness instabilities to enhance their functionality.

  20. 海南热带岛屿非常规突发事件心理危机干预体系脆弱性评价模型初探%RESEARCH OF VULNERABILITY EVALUATING THEORY MODEL OF NON-CONVENTIONAL ACCIDENT PSYCHOLOGICAL CRISIS INTERVENTION IN HAINAN

    Institute of Scientific and Technical Information of China (English)

    蒋湘玲; 郭敏; 高允锁; 王小丹; 蔡俊宏; 郭骏成

    2011-01-01

    [Objective] To explore a set of rational estimate theory of psychological crisis intervention system. [Methods] We applied vulnerability analysis and extension model theory to explores a set of rational estimate theory of psychological crisis intervention system. [Results] The extension model theory was good to evaluate the systemof Non-conventional Accident Psychological Crisis Intervention in Hainan Province because that the information of the index system can be used very fully. [Conclusion] The rational estimate theory of psychological crisis intervention system is not only the basis for intervention policy-making after non-conventional accident, but also to look for psychological rescue couldnot solve by society succor. As our country has a long coasting, our research of psychological crisis of inshore people after non-conventional accident is also the example of non-conventional accident psychological crisis intervention operation in other inshore area.%[目的]探讨心理危机干预系统的合理评价模型.[方法]应用脆弱性分析和可拓模型理论,探讨心理危机干预系统的合理评价模型.[结果]可拓模型理论对心理危机干预指标系统信息利用充分,适于海南热带岛屿非常规突发事件心理危机干预体系脆弱性科学评价.[结论]合理的评价心理危机干预系统不仅能作为非常规突发事件后心理危机干预决策的基础,还能通过深入的分析,寻找社会救援不能解决的心理救护,对其他沿海地区类似非常规突发事件心理危机干预工作中也有实际的借鉴意义.

  1. 因果(鱼刺)图分析法在安全预评价中的应用%Causality (Fishbone) Diagram Analysis in the Pre-assessment Evaluation Unit Construction Project Safety Management Application

    Institute of Scientific and Technical Information of China (English)

    张秀华

    2014-01-01

    In the pre-construction project evaluation process ,safety management is evaluated as an independent unit .In selecting evaluation methods , there are practical difficulties in application security check-list method , due to feasibility stage project preparation period belong ,institutional settings is still in the planning stage ,there is no substantive progress .So Causality (Fishbone) diagram analysis can describe clearly the cause and result of the accident posed by complex causality , builders understand easily the relationship between the accident and take appropriate preventive measures , more appropriate than a checklist .%在建设项目预评价过程中,安全管理一般作为一个独立的单元进行评价;在评价方法的选择上,应用安全检查表法存在现实困难,因可行性论证阶段属于项目的筹建期,机构设置尚处于规划阶段,没有实质性进展。所以说应用因果分析法能把产生事故的原因及造成的结果所构成错综复杂的因果关系描述清楚,更便于建设者了解事故发生的因果关系,采取相应的防范措施,因此比检查表更适宜。

  2. 基于鱼骨图和AHP的研究生知识产权素养影响因素分析%Factors Analysis on Intellectual Property Literacy of Graduate Students Based on Fishbone Diagram and AHP Method

    Institute of Scientific and Technical Information of China (English)

    吴红; 常飞; 李玉平

    2011-01-01

    Aiming at the problem of low literacy of graduate students, the paper uses qualitative and quantitative methods to analyze. First it combs social factors, college factors and individual factors which would have an effect on culturing intellectual property literacy. Then the paper converts the fishbone diagram into hierarchical structure model, structures judge matrix by subjective evaluation, expert evaluation and comprehensive analysis and carries out consistency test. Finally it calculates the importance of various factors relative to the target weight and through total sorting help to grasp the key factors more clearly. On that basis, it effectively promotes the intellectual property literacy of graduate students.%针对高校研究生知识产权素养偏低的问题,采用定性和定量相结合的方法进行分析。首先用鱼骨图法对影响知识产权素养培养的社会因素、高校因素、个体因素进行梳理,然后将鱼骨图转换成层次结构模型,通过主观评价、专家评判和综合分析构造判断矩阵并进行一致性检验,最后计算各个因素相对于目标问题的重要性权重,通过总排序找出关键影响因素,并为有效提升研究生知识产权素养提出建设性意见。

  3. Analysis of operational risk of urban gas based on fishbone diagram analysis%基于鱼骨图分析的城市燃气运营风险要因剖析

    Institute of Scientific and Technical Information of China (English)

    赵煜晖; 乔蓓; 徐俊; 何怡

    2015-01-01

    Based on data of accident case of the urban gas operations ,safety inspection result and accident statistical analysis ,a variety of possible risk factors are identified in the process of city gas operation .And using the risk analysis method based on a fishbone diagram ,11 important risk factors of city gas safety operation are obtained ,such as low pipe and construction quality ,the third party damage ,loss of pipe network data ,loss of geographic information of underground pipe network ,not preventive upgrading ,lack of safety knowledge for users and also lack of safety awareness to employ‐ees ,no odorization ,planning backward ,and lack of enforcement ,etc .Some advices are put forward to prevent risks .%通过城市燃气运营事故案例、安全检查结果与事故统计分析的诸多数据,识别了城市燃气运行过程中存在的各种可能的风险因素,采用基于鱼骨图的风险分析方法,得出了管材及施工质量不高、第三方破坏、设备管网资料缺失、地下管网地理信息缺失、保养不到位、未预防性更新改造、用户安全知识不足、员工安全意识与知识不足、未严格加臭、规划落后、执行不到位11个城市燃气运营的重要风险因素,并据此提出了防范风险的措施及建议。

  4. Capillary Instability in Nanoimprinted Polymer Films

    Energy Technology Data Exchange (ETDEWEB)

    Alvine, Kyle J.; Ding, Yifu; Douglas, Jack F.; Ro, Hyun W.; Okerberg, Brian C.; Karim, Alamgir; Soles, Christopher L.

    2009-07-01

    Capillary forces play an active role in defining the equilibrium structure of nanoscale structures. This effect can be especially pronounced in soft materials such as polymers near or above their glass transition temperature Tg where material flow is possible. In these situations, the effect of surface tension can produce varied and complex capillary instabilities, even in relatively simple geometries such as parallel line-space grating patterns. Here we investigate a novel capillary instability that arises in polystyrene line-space gratings with a residual layer connecting these structures (created by nanoimprint lithography) upon thermal annealing of these patterns. This novel instability is characterized by the development of lateral undulations of the lines that culminates in the local coalescence of adjacent imprinted lines. An exact analytic model of this undulatory instability is not possible, but we introduce a simple physical model for this lateral instability based on the driving force to reduce the surface energy, as in the well-known Rayleigh-Plateau instability which is likewise surface energy driven. Good agreement is obtained between this simplified model and our observations. Our insights into the nature of this instability have implications for controlling the thermal stability of nanoscale patterns made by nanoimprint lithography or other lithography techniques.

  5. The Growth Effects of Institutional Instability

    DEFF Research Database (Denmark)

    Berggren, Niclas; Bergh, Andreas; Bjørnskov, Christian

    . While institutional instability is negatively related to growth in the baseline case, there are indications that the effect can be positive in rich countries, suggesting that institutional reform is not necessarily costly even during a transition period. Sensitivity analysis, e.g., decomposing...... the growth effects of institutional quality and instability, using the political risk index from the ICRG in a cross-country study of 132 countries, measuring instability as the coefficient of variation. Using the aggregate index, we find evidence that institutional quality is positively linked to growth...

  6. The short circuit instability in protoplanetary disks

    DEFF Research Database (Denmark)

    Hubbard, A.; McNally, C.P.; Mac Low, M.M.

    2013-01-01

    We introduce a magneto-hydrodynamic instability which occurs, among other locations, in the inner, hot regions of protoplanetary disks, and which alters the way in which resistive dissipation of magnetic energy into heat proceeds. This instability can be likened to both an electrical short circuit...... and lightning, as it concentrates the dissipation of magnetic energy by means of the enhanced release of free electrons. This instability can generate very high temperatures, making it an excellent candidate for thermally processing protoplanetary disk solids, from annealing silicates to melting chondrules...

  7. Quantum effects in beam-plasma instabilities

    CERN Document Server

    Bret, A

    2015-01-01

    Among the numerous works on quantum effects that have been published in recent years, streaming instabilities in plasma have also been revisited. Both the fluid quantum and the kinetic Wigner-Maxwell models have been used to explore quantum effects on the Weibel, Filamentation and Two-Stream instabilities. While quantum effects usually tend to reduce the instabilities, they can also spur new unstable branches. A number of theoretical results will be reviewed together with the implications to one physical setting, namely the electron driven fast ignition scenario.

  8. More on core instabilities of magnetic monopoles

    CERN Document Server

    Striet, J

    2003-01-01

    In this paper we present new results on the core instability of the 't Hooft Polyakov monopoles we reported on before. This instability, where the spherical core decays in a toroidal one, typically occurs in models in which charge conjugation is gauged. In this paper we also discuss a third conceivable configuration denoted as ``split core'', which brings us to some details of the numerical methods we employed. We argue that a core instability of 't Hooft Polyakov type monopoles is quite a generic feature of models with charged Higgs particles.

  9. Taylor Instability of Incompressible Liquids

    Science.gov (United States)

    Fermi, E.; von Neumann, J.

    1955-11-01

    A discussion is presented in simplified form of the problem of the growth of an initial ripple on the surface of an incompressible liquid in the presence of an acceleration, g, directed from the outside into the liquid. The model is that of a heavy liquid occupying at t = 0 the half space above the plane z = 0, and a rectangular wave profile is assumed. The theory is found to represent correctly one feature of experimental results, namely the fact that the half wave of the heavy liquid into the vacuum becomes rapidly narrower while the half wave pushing into the heavy liquid becomes more and more blunt. The theory fails to account for the experimental results according to which the front of the wave pushing into the heavy liquid moves with constant velocity. The case of instability at the boundary of 2 fluids of different densities is also explored. Similar results are obtained except that the acceleration of the heavy liquid into the light liquid is reduced.

  10. Pulsational-Pair Instability Supernovae

    CERN Document Server

    Woosley, S E

    2016-01-01

    The final evolution of stars in the mass range 60 - 150 solar masses is explored. Depending upon their mass loss and rotation rates, many of these stars will end their lives as pulsational pair-instability supernovae. Even a non-rotating 70 solar mass star is pulsationally unstable during oxygen shell burning and can power a sub-luminous supernova. Rotation decreases the limit further. For more massive stars, the pulsations are less frequent, span a longer time, and are more powerful. Violent pulsations eject not only any residual low density envelope, but also that fraction of the helium core mass outside about 35 - 50 solar masses. The remaining core of helium and heavy elements continues to evolve, ultimately forming an iron core of about 2.5 solar masses that probably collapses to a black hole. A variety of observational transients result with total durations ranging from days to 10,000 years, and luminosities from 10$^{41}$ to 10$^{44}$ erg s$^{-1}$. Many transients resemble ordinary Type IIp supernovae,...

  11. The azimuthal magnetorotational instability (AMRI)

    CERN Document Server

    Ruediger, G; Schultz, M; Hollerbach, R; Stefani, F

    2013-01-01

    We consider the interaction of differential rotation and toroidal fields that are current-free in the gap between two corotating axially unbounded cylinders. It is shown that nonaxisymmetric perturbations are unstable if the rotation rate and Alfven frequency of the field are of the same order almost independent of the magnetic Prandtl number Pm. For the very steep rotation law \\Omega\\propto R^{-2} (the Rayleigh limit) this Azimuthal MagnetoRotational Instability (AMRI) scales with the ordinary Reynolds number and the Hartmann number, which allows a laboratory experiment with liquid metals like sodium or gallium in a Taylor-Couette container. The growth rate of AMRI scales with \\Omega^2 in the low-conductivity limit and with \\Omega in the high-conductivity limit. For the weakly nonlinear system the numerical values of the kinetic energy and the magnetic energy are derived for magnetic Prandtl numbers between 0.05 and unity. We find that the magnetic energy scales with the magnetic Reynolds number Rm, while th...

  12. Transient spirals as superposed instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Sellwood, J. A. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Carlberg, R. G., E-mail: sellwood@physics.rutgers.edu, E-mail: carlberg@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada)

    2014-04-20

    We present evidence that recurrent spiral activity, long manifested in simulations of disk galaxies, results from the superposition of a few transient spiral modes. Each mode lasts between 5 and 10 rotations at its corotation radius where its amplitude is greatest. The scattering of stars as each wave decays takes place over narrow ranges of angular momentum, causing abrupt changes to the impedance of the disk to subsequent traveling waves. Partial reflections of waves at these newly created features allows new standing-wave instabilities to appear that saturate and decay in their turn, scattering particles at new locations, creating a recurring cycle. The spiral activity causes the general level of random motion to rise, gradually decreasing the ability of the disk to support further activity unless the disk contains a dissipative gas component from which stars form on near-circular orbits. We also show that this interpretation is consistent with the behavior reported in other recent simulations with low-mass disks.

  13. Boyle's law and gravitational instability

    CERN Document Server

    Lombardi, M; Lombardi, Marco; Bertin, Giuseppe

    2001-01-01

    We have re-examined the classical problem of the macroscopic equation of state for a hydrostatic isothermal self-gravitating gas cloud bounded by an external medium at constant pressure. We have obtained analytical conditions for its equilibrium and stability without imposing any specific shape and symmetry to the cloud density distribution. The equilibrium condition can be stated in the form of an upper limit to the cloud mass; this is found to be inversely proportional to the power 3/2 of a form factor \\mu characterizing the shape of the cloud. In this respect, the spherical solution, associated with the maximum value of the form factor, \\mu = 1, turns out to correspond to the shape that is most difficult to realize. Surprisingly, the condition that defines the onset of the Bonnor instability (or gravothermal catastrophe) can be cast in the form of an upper limit to the density contrast within the cloud that is independent of the cloud shape. We have then carried out a similar analysis in the two-dimensiona...

  14. Thermal instability of cell nuclei

    Science.gov (United States)

    Warmt, Enrico; Kießling, Tobias R.; Stange, Roland; Fritsch, Anatol W.; Zink, Mareike; Käs, Josef A.

    2014-07-01

    DNA is known to be a mechanically and thermally stable structure. In its double stranded form it is densely packed within the cell nucleus and is thermo-resistant up to 70\\:^\\circ {\\rm{C}}. In contrast, we found a sudden loss of cell nuclei integrity at relatively moderate temperatures ranging from 45 to 55\\:^\\circ {\\rm{C}}. In our study, suspended cells held in an optical double beam trap were heated under controlled conditions while monitoring the nuclear shape. At specific critical temperatures, an irreversible sudden shape transition of the nuclei was observed. These temperature induced transitions differ in abundance and intensity for various normal and cancerous epithelial breast cells, which clearly characterizes different cell types. Our results show that temperatures slightly higher than physiological conditions are able to induce instabilities of nuclear structures, eventually leading to cell death. This is a surprising finding since recent thermorheological cell studies have shown that cells have a lower viscosity and are thus more deformable upon temperature increase. Since the nucleus is tightly coupled to the outer cell shape via the cytoskeleton, the force propagation of nuclear reshaping to the cell membrane was investigated in combination with the application of cytoskeletal drugs.

  15. Careers in conditions of instability

    Directory of Open Access Journals (Sweden)

    Hohlova Valentina Vasil'evna

    2016-04-01

    Full Text Available The purpose of this work is the research of the social-economic phenomenon of a career as a result of conscious human position and behaviour in the field of employment, which is connected with job and professional growth, as a chain of events which are components of life, the sequence of professional activities and other biographical roles, which all together express the commitment of a person’s activity according to his generalized model of self-development. On the basis of the theoretical analysis the dependence of making a career in the condition of instability and indefiniteness on job market flexibility, erosion and even the destruction of the usual way of life and labor relations. The career concepts under the conditions of flexible capitalism and of career policy as the typology of empiric differences of job biographic models are considered. The peculiarity of the proposed career policy concept is that its individual alternatives of career making oppose to organization management and personal demands: the difference between a professional’s wishes and a specific strategy of the development phases are quite noticeable. According to the results of empiric research carried out through the methods of interview, polling, expert assessment, the analysis of the received results, the mathematical data processing the basic types of the career policy and its connection with the organization’s personal development are revealed.

  16. Magnetorotational instability in protoplanetary discs

    CERN Document Server

    Salmeron, Roberto Aureliano; Salmeron, Raquel; Wardle, Mark

    2004-01-01

    We investigate the linear growth and vertical structure of the magnetorotational instability (MRI) in weakly ionised, stratified accretion discs. The magnetic field is initially vertical and dust grains are assumed to have settled towards the midplane, so charges are carried by electrons and ions only. Solutions are obtained at representative radial locations from the central protostar for different choices of the initial magnetic field strength, sources of ionisation, and disc surface density. The MRI is active over a wide range of magnetic field strengths and fluid conditions in low conductivity discs. For the minimum-mass solar nebula model, incorporating cosmic ray ionisation, perturbations grow at 1 AU for B < 8 G. For a significant subset of these strengths (0.2 - 5 G), the growth rate is of order the ideal MHD rate (0.75 Omega). Similarly, when cosmic rays are assumed to be excluded from the disc by the winds emitted by the magnetically active protostar, unstable modes grow at this radius for B less...

  17. Chromosomal instability determines taxane response

    DEFF Research Database (Denmark)

    Swanton, C.; Nicke, B.; Schuett, M.

    2009-01-01

    Microtubule-stabilizing (MTS) agents, such as taxanes, are important chemotherapeutics with a poorly understood mechanism of action. We identified a set of genes repressed in multiple cell lines in response to MTS agents and observed that these genes are overexpressed in tumors exhibiting chromos...... resistance but carboplatin sensitivity, indicating that CIN may determine MTS response in vivo. Thus, pretherapeutic assessment of CIN may optimize treatment stratification and clinical trial design using these agents....... chromosomal instability (CIN). Silencing 22/50 of these genes, many of which are involved in DNA repair, caused cancer cell death, suggesting that these genes are involved in the survival of aneuploid cells. Overexpression of these "CIN-survival'' genes is associated with poor outcome in estrogen receptor......-positive breast cancer and occurs frequently in basal-like and Her2-positive cases. In diploid cells, but not in chromosomally unstable cells, paclitaxel causes repression of CIN-survival genes, followed by cell death. In the OV01 ovarian cancer clinical trial, a high level of CIN was associated with taxane...

  18. Magnetorotational Explosive Instability in Keplerian Disks

    CERN Document Server

    Shtemler, Yuri; Mond, Michael

    2015-01-01

    In this paper it is shown that deferentially rotating disks that are in the presence of weak axial magnetic field are prone to a new nonlinear explosive instability. The latter occurs due to the near-resonance three-wave interactions of a magnetorotational instability with stable Alfven-Coriolis and magnetosonic modes. The dynamical equations that govern the temporal evolution of the amplitudes of the three interacting modes are derived. Numerical solutions of the dynamical equations indicate that small frequency mismatch gives rise to two types of behavior: 1. explosive instability which leads to infinite values of the three amplitudes within a finite time, and 2. bounded irregular oscillations of all three amplitudes. Asymptotic solutions of the dynamical equations are obtained for the explosive instability regimes and are shown to match the numerical solutions near the explosion time.

  19. Shear instabilities in shallow-water magnetohydrodynamics

    CERN Document Server

    Mak, Julian; Hughes, D W

    2016-01-01

    Within the framework of shallow-water magnetohydrodynamics, we investigate the linear instability of horizontal shear flows, influenced by an aligned magnetic field and stratification. Various classical instability results, such as H{\\o}iland's growth rate bound and Howard's semi-circle theorem, are extended to this shallow-water system for quite general profiles. Two specific piecewise-constant velocity profiles, the vortex sheet and the rectangular jet, are studied analytically and asymptotically; it is found that the magnetic field and stratification (as measured by the Froude number) are generally both stabilising, but weak instabilities can be found at arbitrarily large Froude number. Numerical solutions are computed for corresponding smooth velocity profiles, the hyperbolic-tangent shear layer and the Bickley jet, for a uniform background field. A generalisation of the long-wave asymptotic analysis of Drazin & Howard (1962) is employed in order to understand the instability characteristics for both ...

  20. Elliptical instability in terrestrial planets and moons

    CERN Document Server

    Cébron, David; Moutou, Claire; Gal, Patrice Le; 10.1051/0004-6361/201117741

    2012-01-01

    The presence of celestial companions means that any planet may be subject to three kinds of harmonic mechanical forcing: tides, precession/nutation, and libration. These forcings can generate flows in internal fluid layers, such as fluid cores and subsurface oceans, whose dynamics then significantly differ from solid body rotation. In particular, tides in non-synchronized bodies and libration in synchronized ones are known to be capable of exciting the so-called elliptical instability, i.e. a generic instability corresponding to the destabilization of two-dimensional flows with elliptical streamlines, leading to three-dimensional turbulence. We aim here at confirming the relevance of such an elliptical instability in terrestrial bodies by determining its growth rate, as well as its consequences on energy dissipation, on magnetic field induction, and on heat flux fluctuations on planetary scales. Previous studies and theoretical results for the elliptical instability are re-evaluated and extended to cope with ...

  1. Interfacial fluid instabilities and Kapitsa pendula

    CERN Document Server

    Krieger, Madison Ski

    2015-01-01

    The onset and development of instabilities is one of the central problems in fluid mechanics. Here we develop a connection between instabilities of free fluid interfaces and inverted pendula. When acted upon solely by the gravitational force, the inverted pendulum is unstable. This position can be stabilised by the Kapitsa phenomenon, in which high-frequency low-amplitude vertical vibrations of the base creates a fictitious force which opposes the gravitational force. By transforming the dynamical equations governing a fluid interface into an appropriate pendulum, we demonstrate how stability can be induced in fluid systems by properly tuned vibrations. We construct a "dictionary"-type relationship between various pendula and the classical Rayleigh-Taylor, Kelvin-Helmholtz, Rayleigh-Plateau and the self-gravitational instabilities. This makes several results in control theory and dynamical systems directly applicable to the study of "tunable" fluid instabilities, where the critical wavelength depends on the e...

  2. Zonostrophic instability driven by discrete particle noise

    CERN Document Server

    St-Onge, D A

    2016-01-01

    The consequences of discrete particle noise for a system possessing a possibly unstable collective mode are discussed. It is argued that a zonostrophic instability (of homogeneous turbulence to the formation of zonal flows) occurs just below the threshold for linear instability. The scenario provides a new interpretation of the random forcing that is ubiquitously invoked in stochastic models such as the second-order cumulant expansion (CE2) or stochastic structural instability theory (SSST); neither intrinsic turbulence nor coupling to extrinsic turbulence is required. A representative calculation of the zonostrophic neutral curve is made for a simple two-field model of toroidal ion-temperature-gradient-driven modes. To the extent that the damping of zonal flows is controlled by the ion--ion collision rate, the point of zonostrophic instability is independent of that rate.

  3. Kelvin-Helmholtz instability in solar spicules

    Directory of Open Access Journals (Sweden)

    H Ebadi

    2016-12-01

    Full Text Available Magneto hydrodynamic waves, propagating along spicules, may become unstable and the expected instability is of Kelvin-Helmholtz type. Such instability can trigger the onset of wave turbulence leading to an effective plasma heating and particle acceleration. In present study, two-dimensional magneto hydrodynamic simulations performed on a Cartesian grid is presented in spicules with different densities, moving at various speeds depending on their environment. Simulations being applied in this study show the onset of Kelvin-Helmholtz type instability and transition to turbulent flow in spicules. Development of Kelvin-Helmholtz instability leads to momentum and energy transport, dissipation, and mixing of fluids. When magnetic fields are involved, field amplification is also possible to take place

  4. Fluid description for the resonant Weibel instability

    CERN Document Server

    Sarrat, M; Ghizzo, A

    2016-01-01

    We discuss a fluid model with inclusion of the complete pressure tensor dynamics for the description of Weibel type instabilities in a counterstreaming beams configuration. Differently from the case recently studied in Sarrat et al. 2016, where perturbations perpendicular to the beams were considered, here we focus only on modes propagating along the beams. Such a configuration is responsible for the growth of two kind of instabilities, the Two-Stream Instability and the Weibel instability, which in this geometry becomes "time-resonant", i.e. propagative. This fluid description agrees with the kinetic one and makes it possible e.g. to identify the transition between non-propagative and propagative Weibel modes, already evidenced by Lazar et al. 2009 as a "slope-breaking" of the growth rate, in terms of a merger of two non propagative Weibel modes.

  5. Can dust coagulation trigger streaming instability?

    CERN Document Server

    Drazkowska, Joanna

    2014-01-01

    Streaming instability can be a very efficient way of overcoming growth and drift barriers to planetesimal formation. However, it was shown that strong clumping, which leads to planetesimal formation, requires a considerable number of large grains. State-of-the-art streaming instability models do not take into account realistic size distributions resulting from the collisional evolution of dust. We investigate whether a sufficient quantity of large aggregates can be produced by sticking and what the interplay of dust coagulation and planetesimal formation is. We develop a semi-analytical prescription of planetesimal formation by streaming instability and implement it in our dust coagulation code based on the Monte Carlo algorithm with the representative particles approach. We find that planetesimal formation by streaming instability may preferentially work outside the snow line, where sticky icy aggregates are present. The efficiency of the process depends strongly on local dust abundance and radial pressure g...

  6. Electrocapillary instability of magnetic fluid peak

    CERN Document Server

    Mkrtchyan, Levon; Dikansky, Yuri

    2013-01-01

    The paper presents an experimental study of the capillary electrostatic instability occurring under effect of a constant electric field on a magnetic fluid individual peak. The peaks under study occur at disintegration of a magnetic fluid layer applied on a flat electrode surface under effect of a perpendicular magnetic field. The electrocapillary instability shows itself as an emission of charged drops jets from the peak point in direction of the opposing electrode. The charged drops emission repeats periodically and results in the peak shape pulsations. It is shown that a magnetic field affects the electrocapillary instability occurrence regularities and can stimulate its development. The critical electric and magnetic field strengths at which the instability occurs have been measured; their dependence on the peak size is shown. The hysteresis in the system has been studied; it consists in that the charged drops emission stops at a lesser electric (or magnetic) field strength than that of the initial occurr...

  7. Experimental Replication of an Aeroengine Combustion Instability

    Science.gov (United States)

    Cohen, J. M.; Hibshman, J. R.; Proscia, W.; Rosfjord, T. J.; Wake, B. E.; McVey, J. B.; Lovett, J.; Ondas, M.; DeLaat, J.; Breisacher, K.

    2000-01-01

    Combustion instabilities in gas turbine engines are most frequently encountered during the late phases of engine development, at which point they are difficult and expensive to fix. The ability to replicate an engine-traceable combustion instability in a laboratory-scale experiment offers the opportunity to economically diagnose the problem (to determine the root cause), and to investigate solutions to the problem, such as active control. The development and validation of active combustion instability control requires that the causal dynamic processes be reproduced in experimental test facilities which can be used as a test bed for control system evaluation. This paper discusses the process through which a laboratory-scale experiment was designed to replicate an instability observed in a developmental engine. The scaling process used physically-based analyses to preserve the relevant geometric, acoustic and thermo-fluid features. The process increases the probability that results achieved in the single-nozzle experiment will be scalable to the engine.

  8. Nonlinear electrostatic drift Kelvin-Helmholtz instability

    Science.gov (United States)

    Sharma, Avadhesh C.; Srivastava, Krishna M.

    1993-01-01

    Nonlinear analysis of electrostatic drift Kelvin-Helmholtz instability is performed. It is shown that the analysis leads to the propagation of the weakly nonlinear dispersive waves, and the nonlinear behavior is governed by the nonlinear Burger's equation.

  9. Overview of Rayleigh-Taylor instability

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, D.H.

    1983-01-01

    The aim of this talk is to survey Rayleigh-Taylor instability, describing the phenomenology that occurs at a Taylor unstable interface, and reviewing attempts to understand these phenomena quantitatively.

  10. Summary of impedance issues and beam instabilities

    CERN Document Server

    Zimmermann, Frank

    2016-01-01

    This paper summarizes the session on impedance issues and beam instabilities at the ICFA workshop on future circular electron-positron factories “eeFACT2016” [1] held at the Cockcroft Institute, Daresbury, from 24 to 27 October 2016. This session also covered active beam stabilization by feedback systems. Beam-beam effects and coherent beambeam instabilities were addressed separately and, therefore, are not included here.

  11. Jeans instability in the linearized Burnett regime

    CERN Document Server

    García-Colin, L S

    2005-01-01

    Jeans instability is derived for the case of a low density self-gravitating gas beyond the Navier-Stokes equations. The Jeans instability criterium is shown to depend on a Burnett coefficient if the formalism is taken up to fourth order in the wave number. It is also shown that previously known viscosity corrections to the Jeans wave-number are enhanced if the full fourth order formalism is applied to the stability analysis.

  12. Energetic particle instabilities in fusion plasmas

    CERN Document Server

    Sharapov, S E; Berk, H L; Borba, D N; Breizman, B N; Challis, C D; Classen, I G J; Edlund, E M; Eriksson, J; Fasoli, A; Fredrickson, E D; Fu, G Y; Garcia-Munoz, M; Gassner, T; Ghantous, K; Goloborodko, V; Gorelenkov, N N; Gryaznevich, M P; Hacquin, S; Heidbrink, W W; Hellesen, C; Kiptily, V G; Kramer, G J; Lauber, P; Lilley, M K; Lisak, M; Nabais, F; Nazikian, R; Nyqvist, R; Osakabe, M; von Thun, C Perez; Pinches, S D; Podesta, M; Porkolab, M; Shinohara, K; Schoepf, K; Todo, Y; Toi, K; Van Zeeland, M A; Voitsekhovich, I; White, R B; Yavorskij, V; TG, ITPA EP; Contributors, JET-EFDA

    2013-01-01

    Remarkable progress has been made in diagnosing energetic particle instabilities on present-day machines and in establishing a theoretical framework for describing them. This overview describes the much improved diagnostics of Alfven instabilities and modelling tools developed world-wide, and discusses progress in interpreting the observed phenomena. A multi-machine comparison is presented giving information on the performance of both diagnostics and modelling tools for different plasma conditions outlining expectations for ITER based on our present knowledge.

  13. Plasma wave instabilities in nonequilibrium graphene

    DEFF Research Database (Denmark)

    Aryal, Chinta M.; Hu, Ben Yu-Kuang; Jauho, Antti-Pekka

    2016-01-01

    We study two-stream instabilities in a nonequilibrium system in which a stream of electrons is injected into doped graphene. As with equivalent nonequilibrium parabolic band systems, we find that the graphene systems can support unstable charge-density waves whose amplitudes grow with time. We...... of the injected electrons that maximizes the growth rate increases with increasing | q |. We compare the range and strength of the instability in graphene to that of two- and three-dimensional parabolic band systems....

  14. Resonant Triad Instability in Stratified Fluids

    CERN Document Server

    Joubaud, Sylvain; Odier, Philippe; Dauxois, Thierry

    2012-01-01

    Internal gravity waves contribute to fluid mixing and energy transport, not only in oceans but also in the atmosphere and in astrophysical bodies. We provide here the first experimental measurement of the growth rate of a resonant triad instability (also called parametric subharmonic instability) transferring energy to smaller scales where it is dissipated. We make careful and quantitative comparisons with theoretical predictions for propagating vertical modes in laboratory experiments.

  15. On viscoelastic instability in polymeric filaments

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz; Hassager, Ole

    1999-01-01

    The 3D Lagrangian Integral Method is used to simulate the effects of surface tension on the viscoelastic end-plate instability, occuring in the rapid extension of some polymeric filaments between parallel plates. It is shovn that the surface tension delays the onset of the instability. Furthermore...... it is demonstrated that surface tension plays a key role in the selection of the most unstable mode...

  16. ON THE INSTABILITY OF THE RAILWAY VEHICLES

    Directory of Open Access Journals (Sweden)

    Traian MAZILU

    2011-11-01

    Full Text Available The railway vehicles have two sources of instability. The most common is the hunting induced by the reversed conic shape of the rolling surfaces of the wheels. The other one is related by the anomalous Doppler effect that can occurs when the train velocity exceeds the phase velocity of the waves induced in the track structure. Some aspects regarding the two sources of instability are presented.

  17. Studies of elastic-plastic instabilities

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    1999-01-01

    Analyses of plastic instabilities are reviewed, with focus on results in structural mechanics as well as continuum mechanics. First the basic theories for bifurcation and post-bifurcation behavior are briefly presented. Then, localization of plastic flow is discussed, including shear band formation...... in solids, localized necking in biaxially stretched metal sheets, and the analogous phenomenon of buckling localization in structures. Also some recent results for cavitation instabilities in elastic-plastic solids are reviewed....

  18. Systematics of shoulder instability; Systematik der Schulterinstabilitaet

    Energy Technology Data Exchange (ETDEWEB)

    Kreitner, K.F.; Maehringer-Kunz, A. [Johannes-Gutenberg-Universitaet Mainz, Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie, Mainz (Germany)

    2015-03-01

    Shoulder instability is defined as a symptomatic abnormal motion of the humeral head relative to the glenoid during active shoulder motion. Glenohumeral instabilities are classified according to the causative factors as the pathogenesis of instability plays an important role with respect to treatment options. Instabilities are classified into traumatic and atraumatic instabilities as part of a multidirectional instability syndrome and into microtraumatic instabilities. For diagnostics plain radiographs (''trauma series'') are performed to document shoulder dislocation and its successful repositioning. Direct magnetic resonance (MR) arthrography is the most important imaging modality for delineation of the different injury patterns of the labral-ligamentous complex and bony structures. Monocontrast computed tomography (CT) arthrography with the use of multidetector CT scanners represents an alternative imaging modality; however, MR imaging should be preferred in the work-up of shoulder instabilities due to the mostly younger age of patients. (orig.) [German] Unter einer Schulterinstabilitaet versteht man jede zu Beschwerden fuehrende Translation des Humeruskopfs in Relation zur Gelenkpfanne waehrend einer aktiven Bewegung der Schulter. Glenohumerale Instabilitaeten werden heute nach ihrer Aetiologie eingeteilt, da bei der Wahl der Therapie der Entstehungsmechanismus der Instabilitaet eine wichtige Rolle spielt. Danach unterscheidet man primaer traumatisch von atraumatisch entstandenen Instabilitaeten sowie Mikroinstabilitaeten. Bei der Diagnostik dienen konventionelle Roentgenuebersichtsaufnahmen nur noch zur Dokumentation einer Luxation und zur Beurteilung der Reposition. Die durch eine Instabilitaet hervorgerufenen Verletzungsfolgen am labroligamentaeren Komplex und den knoechernen Strukturen werden heute bevorzugt mit der direkten MR-Arthrographie dargestellt. Hierbei koennen unterschiedliche Verletzungsmuster dargestellt werden. Nach

  19. Weibel instability in relativistic quantum plasmas

    Science.gov (United States)

    Mendonça, J. T.; Brodin, G.

    2015-08-01

    Generation of quasi-static magnetic fields, due to the Weibel instability is studied in a relativistic quantum plasma. This instability is induced by a temperature anisotropy. The dispersion relation and growth rates for low frequency electromagnetic perturbations are derived using a wave-kinetic equation which describes the evolution of the electron Wigner quasi-distribution. The influence of parallel kinetic effects is discussed in detail.

  20. A hydrodynamic approach to QGP instabilities

    CERN Document Server

    Calzetta, E

    2013-01-01

    We show that the usual linear analysis of QGP Weibel instabilities based on the Maxwell-Boltzmann equation may be reproduced in a purely hydrodynamic model. The latter is derived by the Entropy Production Variational Method from a transport equation including collisions, and can describe highly nonequilibrium flow. We find that, as expected, collisions slow down the growth of Weibel instabilities. Finally, we discuss the strong momentum anisotropy limit.

  1. Correlation of OPLL with spinal instability

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Chul; Chung, Tae Sub; Kim, Young Soo [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

    1998-08-01

    To evaluate the relationship between spinal instability and ossification of the posterior longitudinal ligament(OPLL). Materials and Methods: In 70 patients(M:F=45:25, mean age=53 years) diagnosed as OPLL on the basis of surgical operation field findings and radiological evaluation [plain film(n=70), CT(n=64),MRI(n=55)], involved levels were the cervical spine(n=32), lumbar spine(n=23), and both the cervical and lumbar spine(n=15). Spinal instability was radiologically diagnosed as horizontal displacement of one vertebra by another of more than 3.5 mm, or a difference in rotation from either adjacent vertebra by more than 11 degree in lateral cervical spine and a difference of more than 1.5 mm from the posterior body margins to the point of intersection of two lines drawn parallel to the opposing segmental endplate in extension lateral lumbar spine. We divided OPLL into group I(continuous, segmental, mixed) and group II(retrodiscal), and compared spinal instability in these two groups. Results: In cervical OPLL, group I comprised 33 cases and group II 14. In group I, spinal instability was noted in 8/33 cases(24%) or 10/123 segments(8.1%). Spinal instability in group II, on the other hand, was found in 13/14 cases(93%) or 17/26 segments(65%). Ossification occurred at the retrodiscal level in 37 cases, byt in case was continuous. In group II, spinal instability was found in 25 of 37 cases(69%), oe in 29 of 55 segments(53%). Conclusion: Compared to other types of OPLL, the frequency of retrodiscal OPLL in association with spinal instability was high. Spinal instability may thus be the most important cause of retrodiscal OPLL.

  2. Beam Instabilities in Circular Particle Accelerators

    CERN Document Server

    Metral, Elias

    2017-01-01

    The theory of impedance-induced bunched-beam coherent instabilities is reviewed following Laclare's formalism, adding the effect of an electronic damper in the transverse plane. Both single-bunch and coupled-bunch instabilities are discussed, both low-intensity and high-intensity regimes are analysed, both longitudinal and transverse planes are studied, and both short-bunch and long-bunch regimes are considered. Observables and mitigation measures are also examined.

  3. Spinal instability in ankylosing spondylitis

    Directory of Open Access Journals (Sweden)

    Badve Siddharth

    2010-01-01

    Full Text Available Background: Unstable spinal lesions in patients with ankylosing spondylitis are common and have a high incidence of associated neurological deficit. The evolution and presentation of these lesions is unclear and the management strategies can be confusing. We present retrospective analysis of the cases of ankylosing spondylitis developing spinal instability either due to spondylodiscitis or fractures for mechanisms of injury, presentations, management strategies and outcome. Materials and Methods: In a retrospective analysis of 16 cases of ankylosing spondylitis, treated surgically for unstable spinal lesions over a period of 12 years (1995-2007; 87.5% (n=14 patients had low energy (no obvious/trivial trauma while 12.5% (n=2 patients sustained high energy trauma. The most common presentation was pain associated with neurological deficit. The surgical indications included neurological deficit, chronic pain due to instability and progressive deformity. All patients were treated surgically with anterior surgery in 18.8% (n=3 patients, posterior in 56.2% (n=9 patients and combined approach in 25% (n=4 patients. Instrumented fusion was carried out in 87.5% (n=14 patients. Average surgical duration was 3.84 (Range 2-7.5 hours, blood loss 765.6 (± 472.5 ml and follow-up 54.5 (Range 18-54 months. The patients were evaluated for pain score, Frankel neurological grading, deformity progression and radiological fusion. One patient died of medical complications a week following surgery. Results: Intra-operative adverse events like dural tears and inadequate deformity correction occurred in 18.7% (n=3 patients (Cases 6, 7 and 8 which could be managed conservatively. There was a significant improvement in the Visual analogue score for pain from a pre-surgical median of 8 to post-surgical median of 2 (P=0.001, while the neurological status improved in 90% (n=9 patients among those with preoperative neurological deficit who could be followed-up (n =10. Frankel

  4. The Abelianization of QCD Plasma Instabilities

    CERN Document Server

    Arnold, P; Arnold, Peter; Lenaghan, Jonathan

    2004-01-01

    QCD plasma instabilities appear to play an important role in the equilibration of quark-gluon plasmas in heavy-ion collisions in the theoretical limit of weak coupling (i.e. asymptotically high energy). It is important to understand what non-linear physics eventually stops the exponential growth of unstable modes. It is already known that the initial growth of plasma instabilities in QCD closely parallels that in QED. However, once the unstable modes of the gauge-fields grow large enough for non-Abelian interactions between them to become important, one might guess that the dynamics of QCD plasma instabilities and QED plasma instabilities become very different. In this paper, we give suggestive arguments that non-Abelian self-interactions between the unstable modes are ineffective at stopping instability growth, and that the growing non-Abelian gauge fields become approximately Abelian after a certain stage in their growth. This in turn suggests that understanding the development of QCD plasma instabilities i...

  5. On the chiral imbalance and Weibel instabilities

    Science.gov (United States)

    Kumar, Avdhesh; Bhatt, Jitesh R.; Kaw, P. K.

    2016-06-01

    We study the chiral-imbalance and the Weibel instabilities in presence of the quantum anomaly using the Berry-curvature modified kinetic equation. We argue that in many realistic situations, e.g. relativistic heavy-ion collisions, both the instabilities can occur simultaneously. The Weibel instability depends on the momentum anisotropy parameter ξ and the angle (θn) between the propagation vector and the anisotropy direction. It has maximum growth rate at θn = 0 while θn = π / 2 corresponds to a damping. On the other hand the pure chiral-imbalance instability occurs in an isotropic plasma and depends on difference between the chiral chemical potentials of right and left-handed particles. It is shown that when θn = 0, only for a very small values of the anisotropic parameter ξ ∼ξc, growth rates of the both instabilities are comparable. For the cases ξc Weibel modes dominate over the chiral-imbalance instability if μ5 / T ≤ 1. However, when μ5 / T ≥ 1, it is possible to have dominance of the chiral-imbalance modes at certain values of θn for an arbitrary ξ.

  6. [Capsular retensioning in anterior unidirectional glenohumeral instability].

    Science.gov (United States)

    Benítez Pozos, Leonel; Martínez Molina, Oscar; Castañeda Landa, Ezequiel

    2007-01-01

    To present the experience of the Orthopedics Service PEMEX South Central Hospital in the management of anterior unidirectional shoulder instability with an arthroscopic technique consisting of capsular retensioning either combined with other anatomical repair procedures or alone. Thirty-one patients with anterior unidirectional shoulder instability operated-on between January 1999 and December 2005 were included. Fourteen patients underwent capsular retensioning and radiofrequency, and in 17 patients, capsular retensioning was combined with suture anchors. Patients with a history of relapsing glenohumeral dislocations and subluxations, with anterior instability with or without associated Bankart lesions were selected; all of them were young. The results were assessed considering basically the occurrence of instability during the postoperative follow-up. No cases of recurring instability occurred. Two cases had neuroma and one experienced irritation of the suture site. Six patients had residual limitation of combined lateral rotation and abduction movements, of a mean of 10 degrees compared with the healthy contralateral side. The most frequent incident was the leak of solutions to the soft tissues. Capsular retensioning, whether combined or not with other anatomical repair techniques, has proven to result in a highly satisfactory rate of glenohumeral stabilization in cases of anterior unidirectional instabilities. The arthroscopic approach offers the well-known advantages of causing less damage to the soft tissues, and a shorter time to starting rehabilitation therapy and exercises.

  7. Beam-Ion Instability in PEP-II

    Energy Technology Data Exchange (ETDEWEB)

    Heifets, S.; Kulikov, A.; Wang, Min-Huey; Wienands, U.; /SLAC

    2007-11-07

    The instability in the PEP-II electron ring has been observed while reducing the clearing gap in the bunch train. We study the ion effects in the ring summarizing existing theories of the beam-ion interaction, comparing them with observations, and estimating effect on luminosity in the saturation regime. Considering the gap instability we suggest that the instability is triggered by the beam-ion instability, and discuss other mechanisms pertinent to the instability.

  8. Laser pulse modulation instabilities in partially stripped plasma

    Institute of Scientific and Technical Information of China (English)

    Hu Qiang-Lin; Liu Shi-Bing; Jiang Yi-Jian

    2005-01-01

    The laser pulse modulation instabilities in partially stripped plasma were discussed based on the phase and group velocities of the laser pulse and the two processes that modulation instabilities excited. The excitation condition and growth rate of the modulation instability were obtained. It was found that the positive chirp and competition between normal and abnormal dispersions play important roles in the modulation instability. In the partially stripped plasma,the increased positive chirp enhances the modulation instability, and the dispersion competition reduces it.

  9. Instabilities in Interacting Binary Stars

    Science.gov (United States)

    Andronov, I. L.; Andrych, K. D.; Antoniuk, K. A.; Baklanov, A. V.; Beringer, P.; Breus, V. V.; Burwitz, V.; Chinarova, L. L.; Chochol, D.; Cook, L. M.; Cook, M.; Dubovský, P.; Godlowski, W.; Hegedüs, T.; Hoňková, K.; Hric, L.; Jeon, Y.-B.; Juryšek, J.; Kim, C.-H.; Kim, Y.; Kim, Y.-H.; Kolesnikov, S. V.; Kudashkina, L. S.; Kusakin, A. V.; Marsakova, V. I.; Mason, P. A.; Mašek, M.; Mishevskiy, N.; Nelson, R. H.; Oksanen, A.; Parimucha, S.; Park, J.-W.; Petrík, K.; Quiñones, C.; Reinsch, K.; Robertson, J. W.; Sergey, I. M.; Szpanko, M.; Tkachenko, M. G.; Tkachuk, L. G.; Traulsen, I.; Tremko, J.; Tsehmeystrenko, V. S.; Yoon, J.-N.; Zola, S.; Shakhovskoy, N. M.

    2017-07-01

    The types of instability in the interacting binary stars are briefly reviewed. The project “Inter-Longitude Astronomy” is a series of smaller projects on concrete stars or groups of stars. It has no special funds, and is supported from resources and grants of participating organizations, when informal working groups are created. This “ILA” project is in some kind similar and complementary to other projects like WET, CBA, UkrVO, VSOLJ, BRNO, MEDUZA, AstroStatistics, where many of us collaborate. Totally we studied 1900+ variable stars of different types, including newly discovered variables. The characteristic timescale is from seconds to decades and (extrapolating) even more. The monitoring of the first star of our sample AM Her was initiated by Prof. V.P. Tsesevich (1907-1983). Since more than 358 ADS papers were published. In this short review, we present some highlights of our photometric and photo-polarimetric monitoring and mathematical modeling of interacting binary stars of different types: classical (AM Her, QQ Vul, V808 Aur = CSS 081231:071126+440405, FL Cet), asynchronous (BY Cam, V1432 Aql), intermediate (V405 Aql, BG CMi, MU Cam, V1343 Her, FO Aqr, AO Psc, RXJ 2123, 2133, 0636, 0704) polars and magnetic dwarf novae (DO Dra) with 25 timescales corresponding to different physical mechanisms and their combinations (part “Polar”); negative and positive superhumpers in nova-like (TT Ari, MV Lyr, V603 Aql, V795 Her) and many dwarf novae stars (“Superhumper”); eclipsing “non-magnetic” cataclysmic variables(BH Lyn, DW UMa, EM Cyg; PX And); symbiotic systems (“Symbiosis”); super-soft sources (SSS, QR And); spotted (and not spotted) eclipsing variables with (and without) evidence for a current mass transfer (“Eclipser”) with a special emphasis on systems with a direct impact of the stream into the gainer star's atmosphere, which we propose to call “Impactor” (short from “Extreme Direct Impactor”), or V361 Lyr-type stars. Other

  10. Risk Measurement and Evaluation of Public Safety Based on Fishbone Diagram%基于鱼骨图的公共安全风险测度与评价

    Institute of Scientific and Technical Information of China (English)

    孙华丽; 周战杰; 薛耀锋

    2011-01-01

    To measure regional public risk scientifically and improve regional public safety, an evaluation index system is built based on fishbone diagram, which includes the indexes of ability and vulnerability. With the help of SPSS (Statistical Program for Social Sciences) software, the public safety risks for 31 provinces or municipal cities in China are calculated by using PC A, and their risks are ranked. Meanwhile, the key components affecting regional public risk are found out, which provides a good reference for risk alleviation. The result shows that there are big differences in the risk level of public safety in these areas; the components of public safety resources and support system are the most important factors affecting regional public risk, and increasing investment in infrastructure, especially in the infrastructure of social security system, can alleviate the regional public safety risk.%为科学测度我国各地区公共安全风险,改善公共安全状况.基于鱼骨图分析法,建立包括能力和脆弱性指标的公共安全评价指标体系.采用主成分分析法(PCA),结合统计软件SPSS对我国31个省市的公共安全风险进行测度,找出影响公共安全水平的重要因子,计算出各省市公共安全风险的综合评价值,得到不同省市的风险排序,为改善公共安全风险较高地区的安全状况提供了启示.结果表明:我国各地区公共安全的风险水平差异较大且公共安全资源和保障因子是影响公共安全抗风险水平的最重要因子,加大基础设施投资,特别是社会保障类基础设施建设投资,可较好地改善公共安全抗风险状况.

  11. Dynamic Instability of Rapidly Rotating Protostars

    Science.gov (United States)

    Pickett, B. K.; Durisen, R. H.; Johnson, M. S.; Davis, G. A.

    1994-12-01

    Modern studies of collapse and fragmentation of protostellar clouds suggest a wide variety of outcomes, depending on the assumed initial conditions. Individual equilibrium objects which result from collapse are likely to be in rapid rotation and can have a wide range of structures. We have undertaken a survey of parameter space in order to examine the role of dynamic instabilities in the subsequent evolution of these objects. For the purposes of conducting a systematic study, we so far have considered only the n = 3/2 polytropic equilibrium states that might form from the collapse of uniformly rotating spherical clouds. By varying the central concentration of the assumed initial cloud, we obtain equilibrium states distinguished primarily by their different specific angular momentum distributions. These equilibrium states span the range between starlike objects with angular momentum distributions analogous to the Maclaurin spheroids and objects more accurately described as massive Keplerian disks around stars. Using a new SCF code to generate the n = 3/2 axisymmetric equilibrium states and an improved 3D hydrodynamics code, we have investigated the the onset and nature of global dynamic instabilities in these objects. The starlike objects are unstable to barlike instabilities at T/|W| gtorder 0.27, where T/|W| is the ratio of total rotational kinetic energy to gravitational potential energy. These instabilities are vigorous and lead to violent ejection of mass and angular momentum. As the angular momentum distribution shifts to the other extreme, one- and two-armed spiral instabilities begin to dominate at considerably lower T/|W|. These instabilities appear to be driven by the SLING and swing mechanisms. In extremely flattened disks, one-armed spirals dominate all other disturbances but eventually saturate at nonlinear amplitude without producing fragmentation. We conclude that the nature of the global instabilities encountered during the process of star formation

  12. Intimate partner violence and housing instability.

    Science.gov (United States)

    Pavao, Joanne; Alvarez, Jennifer; Baumrind, Nikki; Induni, Marta; Kimerling, Rachel

    2007-02-01

    The mental and physical health consequences of intimate partner violence (IPV) have been well established, yet little is known about the impact of violence on a woman's ability to obtain and maintain housing. This cross-sectional study examines the relationship between recent IPV and housing instability among a representative sample of California women. It is expected that women who have experienced IPV will be at increased risk for housing instability as evidenced by: (1) late rent or mortgage, (2) frequent moves because of difficulty obtaining affordable housing, and/or (3) without their own housing. Data were taken from the 2003 California Women's Health Survey, a population-based, random-digit-dial, annual probability survey of adult California women (N=3619). Logistic regressions were used to predict housing instability in the past 12 months, adjusting for the following covariates; age, race/ethnicity, education, poverty status, marital status, children in the household, and past year IPV. In the multivariate model, age, race/ethnicity, marital status, poverty, and IPV were significant predictors of housing instability. After adjusting for all covariates, women who experienced IPV in the last year had almost four times the odds of reporting housing instability than women who did not experience IPV (adjusted odds ratio=3.98, 95% confidence interval: 2.94-5.39). This study found that IPV was associated with housing instability among California women. Future prospective studies are needed to learn more about the nature and direction of the relationship between IPV and housing instability and the possible associated negative health consequences.

  13. Dynamical instabilities in disc-planet interactions

    CERN Document Server

    Lin, Min-Kai

    2012-01-01

    Protoplanetary discs may become dynamically unstable due to structure induced by an embedded giant planet. In this thesis, I discuss the stability of such systems and explore the consequence of instability on planetary migration. I begin with non-self-gravitating, low viscosity discs and show that giant planets induce shocks inside its co-orbital region, leading to a profile unstable to vortex formation around a potential vorticity minimum. This instability is commonly known as the vortex or Rossby wave instability. Vortex-planet interaction lead to episodic phases of migration, which can be understood in the framework of type III migration. I then examine the effect of disc self-gravity on gap stability. The linear theory of the Rossby wave instability is extended to include disc gravity, which shows that self-gravity is effective at stabilising the vortex instability at small azimuthal wavenumber. This is consistent with the observation that more vortices develop with increasing disc mass in hydrodynamic si...

  14. Coherent Instabilities of ILC Damping Ring

    Energy Technology Data Exchange (ETDEWEB)

    Heifets, S.; Stupakov, G.; Bane, K.; /SLAC

    2006-09-27

    The paper presents the first attempt to estimates the ILC damping ring impedance and compare thresholds of the classical instabilities for several designs initially proposed for the DR. The work was carried out in the spring of 2006. Since then the choice of the DR is narrowed. Nevertheless, the analysis described may be useful for the next iterations of the beam stability. Overall, the conventional instabilities will have little impact on the ring performance provided the careful design of the ring minimizes the impedance below acceptable level indicated above. The only exception is the transverse CB instability. The longitudinal CB is less demanding. However, even the transverse CB instability would have threshold current above nominal provided the aperture in the wigglers is increased from 8 mm to 16 mm. The microwave instability needs more studies. Nevertheless, we should remember that the ILC DR is different from existing high-current machines at least in two respects: absence of the beam-beam tune spread stabilizing beams in colliders, and unusual strict requirements for low emittance. That may cause new problems such as bunch emittance dilution due to high-frequency wakes (BPMs, grooves), etc. Even if such a possibility exists, it probably universal for all machines and ought be addressed in the design of vacuum components rather than have effect on the choice of the machine design.

  15. Tidal instability in exoplanetary systems evolution

    Directory of Open Access Journals (Sweden)

    Le Gal P.

    2011-02-01

    Full Text Available A new element is proposed to play a role in the evolution of extrasolar planetary systems: the tidal (or elliptical instability. It comes from a parametric resonance and takes place in any rotating fluid whose streamlines are (even slightly elliptically deformed. Based on theoretical, experimental and numerical works, we estimate the growth rate of the instability for hot-jupiter systems, when the rotation period of the star is known. We present the physical process, its application to stars, and preliminary results obtained on a few dozen systems, summarized in the form of a stability diagram. Most of the systems are trapped in the so-called "forbidden zone", where the instability cannot grow. In some systems, the tidal instability is able to grow, at short timescales compared to the system evolution. Implications are discussed in the framework of misaligned transiting systems, as the rotational axis of the star would be unstable in systems where this elliptical instability grows.

  16. Diffusive Magnetohydrodynamic Instabilities beyond the Chandrasekhar Theorem

    Science.gov (United States)

    Rüdiger, Günther; Schultz, Manfred; Stefani, Frank; Mond, Michael

    2015-10-01

    We consider the stability of axially unbounded cylindrical flows that contain a toroidal magnetic background field with the same radial profile as their azimuthal velocity. For ideal fluids, Chandrasekhar had shown the stability of this configuration if the Alfvén velocity of the field equals the velocity of the background flow, i.e., if the magnetic Mach number {Mm}=1. We demonstrate that magnetized Taylor-Couette flows with such profiles become unstable against non-axisymmetric perturbations if at least one of the diffusivities is finite. We also find that for small magnetic Prandtl numbers {Pm} the lines of marginal instability scale with the Reynolds number and the Hartmann number. In the limit {Pm}\\to 0 the lines of marginal instability completely lie below the line for {Mm}=1 and for {Pm}\\to ∞ they completely lie above this line. For any finite value of {Pm}, however, the lines of marginal instability cross the line {Mm}=1, which separates slow from fast rotation. The minimum values of the field strength and the rotation rate that are needed for the instability (slightly) grow if the rotation law becomes flat. In this case, the electric current of the background field becomes so strong that the current-driven Tayler instability (which also exists without rotation) appears in the bifurcation map at low Hartmann numbers.

  17. Soliton modulation instability in fiber lasers

    Science.gov (United States)

    Tang, D. Y.; Zhao, L. M.; Wu, X.; Zhang, H.

    2009-08-01

    We report experimental evidence of soliton modulation instability in erbium-doped fiber lasers. An alternate type of spectral sideband generation was always experimentally observed on the soliton spectrum of the erbium-doped soliton fiber lasers when energy of the formed solitons reached beyond a certain threshold value. Following this spectral sideband generation, if the pump power of the lasers was further increased, either a new soliton would be formed or the existing solitons would experience dynamical instabilities, such as the period-doubling bifurcations or period-doubling route to chaos. We point out that the mechanism for this soliton spectral sideband generation is the modulation instability of the solitons in the lasers. We further show that, owing to the internal energy balance of a dissipative soliton, modulation instability itself does not destroy the stable soliton evolution in a laser cavity. It is the strong resonant wave coupling between the soliton and dispersive waves that leads to the dynamic instability of the solitons.

  18. Competition between Buneman and Langmuir Instabilities

    Institute of Scientific and Technical Information of China (English)

    GUO Jun; YU Bin

    2012-01-01

    The electron-ion beam instabilities are studied by one-dimensional electrostatic particle-in-cell simulation.The simulation results show that both the low-frequency Buneman mode and high-frequency Langmuir wave (LW) are excited in the nonlinear phase. The power of Buneman instability is stronger than that of the LW.The Buneman instability is firstly excited.Then the backward LW appears,which is probably excited by the particles trapped in the wave potential and moving opposite to the original beam direction.After some time,the forward LW can be found,which has a larger maximum frequency than that of the backward LW.With the decrease of the electron drift velocity,the instabilities become weaker; the LW appears to have almost equal intensities and becomes symmetric for forward and backward propagation directions. The LW can also heat the electron,so the relative drift speed cannot far exceed the electron thermal speed,which is not helpful to the development of Buneman instability.

  19. On the Chiral imbalance and Weibel Instabilities

    CERN Document Server

    Kumar, Avdhesh; Kaw, Predhiman K

    2016-01-01

    We study the chiral-imbalance and the Weibel instabilities in presence of the quantum anomaly using the Berry-curvature modified kinetic equation. We argue that in many realistic situations, e.g. relativistic heavy-ion collisions, both the instabilities can occur simultaneously. The Weibel instability depends on the momentum anisotropy parameter $\\xi$ and the angle ($\\theta_n$) between the propagation vector and the anisotropy direction. It has maximum growth rate at $\\theta_n=0$ while $\\theta_n=\\pi/2$ corresponds to a damping. On the other hand the pure chiral-imbalance instability occurs in an isotropic plasma and depends on difference between the chiral chemical potentials of right and left-handed particles. It is shown that when $\\theta_n=0$, only for a very small values of the anisotropic parameter $\\xi\\sim \\xi_c$, growth rates of the both instabilities are comparable. For the cases $\\xi_c<\\xi\\ll1$, $\\xi\\approx 1$ or $\\xi \\geq 1$ at $\\theta_n=0$, the Weibel modes dominate over the chiral-imbalance ins...

  20. Pressure-driven instabilities in astrophysical jets

    CERN Document Server

    Longaretti, Pierre-Yves

    2008-01-01

    Astrophysical jets are widely believed to be self-collimated by the hoop-stress due to the azimuthal component of their magnetic field. However this implies that the magnetic field is largely dominated by its azimuthal component in the outer jet region. In the fusion context, it is well-known that such configurations are highly unstable in static columns, leading to plasma disruption. It has long been pointed out that a similar outcome may follow for MHD jets, and the reasons preventing disruption are still not elucidated, although some progress has been accomplished in the recent years. In these notes, I review the present status of this open problem for pressure-driven instabilities, one of the two major sources of ideal MHD instability in static columns (the other one being current-driven instabilities). I first discuss in a heuristic way the origin of these instabilities. Magnetic resonances and magnetic shear are introduced, and their role in pressure-driven instabilities discussed in relation to Suydam'...

  1. Multiphase Instabilities in Explosive Dispersal of Particles

    Science.gov (United States)

    Rollin, Bertrand; Ouellet, Frederick; Annamalai, Subramanian; Balachandar, S. ``Bala''

    2015-11-01

    Explosive dispersal of particles is a complex multiphase phenomenon that can be observed in volcanic eruptions or in engineering applications such as multiphase explosives. As the layer of particles moves outward at high speed, it undergoes complex interactions with the blast-wave structure following the reaction of the energetic material. Particularly in this work, we are interested in the multiphase flow instabilities related to Richmyer-Meshkov (RM) and Rayleigh-Taylor (RM) instabilities (in the gas phase and particulate phase), which take place as the particle layer disperses. These types of instabilities are known to depend on initial conditions for a relatively long time of their evolution. Using a Eulerian-Lagrangian approach, we study the growth of these instabilities and their dependence on initial conditions related to the particulate phase - namely, (i) particle size, (ii) initial distribution, and (iii) mass ratio (particles to explosive). Additional complexities associated with compaction of the layer of particles are avoided here by limiting the simulations to modest initial volume fraction of particles. A detailed analysis of the initial conditions and its effects on multiphase RM/RT-like instabilities in the context of an explosive dispersal of particles is presented. This work was supported by the U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science Academic Alliance Program, Contract No. DE-NA0002378.

  2. A Non-Conventional IR Approach to India's Foreign Policy

    DEFF Research Database (Denmark)

    Schmidt, Johannes Dragsbæk

    that an alternative Critical IPE approach (CPE) contributes to a more nuanced understanding of India's foreign policy. In generic terms, shifting governments have a variety of options both in defining and refining what 'national interest' means, how security and threats are perceived, and which factors shape geo......-economic and geopolitical relations to other countries. The CPE approach does not essentialize the state as a pre-constituted entity or a ‘black box’ of “national interests” interacting within anarchical international relations. Rather, CPE seeks to understand ‘forms of states’ as ‘state/society complex’ and asks how...

  3. Archaeomagnetic studies in Mesoamerica using non-conventional materials

    Science.gov (United States)

    Soler-Arechalde, A.; Gogichaishvili, A.; Urrutia-Fucugauchi, J.

    2004-12-01

    For the first time results of an archaeomagnetic study of mural paintings and unburned lime-plasters from Mesoamerica are presented. The magnetic measurements show that at least four murals (sites: Cacaxtla, Cholula and Templo Mayor) retain a remanent magnetization carried by a mixture of hematite and magnetite grains. In most specimens, a characteristic magnetization is successfully isolated by alternating field demagnetization. The mean directions are reasonably well determined for each murals and within the range of secular variation during the last centuries. Studied Mesoamerican murals apparently retain the direction of the magnetic field at the time they were painted and are therefore an invaluable source of information concerning its secular variation. Lime-plaster samples were selected from two archaeological excavation projects in the Teopancazco residential compound of Teotihuacan and the large multi-stage structure of Templo Mayor in Tenochtitlan, where chronological information is available. The intensity of remanent magnetization and low-field susceptibility are weak reflecting low relative content of magnetic minerals. NRM directions are well grouped and alternating field demagnetization shows single or two-component magnetizations. Rock-magnetic experiments point to fine-grained titanomagnetites with pseudo-single domain behavior. Anisotropy of magnetic susceptibility measurements document a depositional fabric, with normal to free-surface minimum AMS axes. Characteristic mean site directions were correlated to the paleosecular variation curve for Mesoamerica. Our results suggest that archaeomagnetic dating can be applied to mural paintings and lime-plasters, which are materials widely employed in Mesoamerica.

  4. Performance of non-conventional factorization approaches for neutron kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Bulla, S.; Nervo, M. [Politecnico di Torino, Dipartimento Energia, Corso Duca degli Abruzzi, 24, 10129 Torino (Italy)

    2013-07-01

    The use of factorization techniques provides a interesting option for the simulation of the time-dependent behavior of nuclear systems with a reduced computational effort. While point kinetics neglects all spatial and spectral effects, quasi-statics and multipoint kinetics allow to produce results with a higher accuracy for transients involving relevant modifications of the neutron distribution. However, in some conditions these methods can not work efficiently. In this paper, we discuss some possible alternative formulations for the factorization process for neutron kinetics, leading to mathematical models of reduced complications that can allow an accurate simulation of transients involving spatial and spectral effects. The performance of these innovative approaches are compared to standard techniques for some test cases, showing the benefits and shortcomings of the method proposed. (authors)

  5. China's Research on Non-conventional Energy Resources- Gas Hydrate

    Institute of Scientific and Technical Information of China (English)

    Pu Ming; Ma Jianguo

    2002-01-01

    @@ Methane exists in ice-like formations called gas hydrate. Hydrate traps methane molecules inside a cage of frozen water. The magnitude of this previously unknown global storehouse of methane is truly staggering and has raised serious inquiry into the possibility of using methane hydrate as a substitute source of energy for oil and conventional natural gas. According to the estimation by PGC, gas hydrate deposits amount to 7.6 × 1018m3 and contain more than twice as much organic carbon as all the world's coal, oil and non-hydrate natural gas combined.

  6. NON-CONVENTIONAL TOOLS OF COHESION IN CONTEMPORARY RUSSIAN POETRY

    Directory of Open Access Journals (Sweden)

    Svetlana Yu. Bochaver

    2016-01-01

    Full Text Available The subject of research in this article is syntactic ambiguity; the material for analysis was based on the texts of modern Russian poets created over the last 35 years. The article analyzes the poetry of authors such as G. Aygi, V. Aristov, N. Azarova, D. Gatina, G. Rymbu, A. Cherkasov, K. Korchagin and others representing different generations of poets. The syntactic ambiguity was examined as corresponding to the verse graphics, in particular, division into lines, stanzas and strophoids. In the context of the modern poetic utterance, the line skip and splitting into strophoids and quasi-strophoids may be regarded as a new way of placing punctuation marks, and the very appearance of this sign draws the reader’s attention to the syntactic ambiguity emerging at the line end. Withdrawing from the traditional and conventional punctuation marks can be related to the strategy of deliberate creation and enhancement of syntactic ambiguities in the text. The paper demonstrates the varying possibilities of reading and interpreting the poetic text containing syntactic ambiguity. Addressing the present-time materials makes it possible not only to describe one of the stages of development of the Russian poetic language, but also to clarify some theoretical principles of syntactic analysis of the poetic text. 

  7. A Non-Conventional IR Approach to India's Foreign Policy

    DEFF Research Database (Denmark)

    Schmidt, Johannes Dragsbæk

    Paper presentation for the Panel 'India's international relations: empirical and theoretical perspectives'. EISA Pan-Euro Conference in Warsaw, 18 - 21st September, 2013 Abstract The paper elaborates on a critique of mainstream IR theory - neo-realism and liberal IR - and suggests...

  8. Innovative Technologies for Maskless Lithography and Non-Conventional Patterning

    Science.gov (United States)

    2008-08-01

    illuminated with a thermionic gun and whose focusing was entirely by the above magnetic field. We observed values of resolution between 30nm and 50nm at...The approach described here employs a uniform magnetic field to focus thousands of electron beams simultaneously and operates with unity...endgroup, phase compatibility with the resin, dissolution inhibition capabilities of the resin, and a solubility switch once exposed. Modeling Nanoscale

  9. Non Conventional Livestock for Better Livelihood: Prospects of ...

    African Journals Online (AJOL)

    Meanwhile, there have been growing demands for white meats, especially among the middle and high income population classes, exacerbated by changes in eating ... from research and extension services are called for to improve production, ...

  10. Applications of the Non-Conventional Yeast Yarrowia lipolytica

    Science.gov (United States)

    Thevenieau, France; Nicaud, Jean-Marc; Gaillardin, Claude

    The yeast Yarrowia lipolytica is often found associated to proteinaceous or hydrophobic substrates such as alkanes or lipids. To assimilate these hydropho-bic substrates, Y. lipolytica has developed an adaptative strategy resulting in elaborated morphological and physiological changes leading to terminal and β-oxidation of substrates as well as to lipid storage. The completion of the Y. lipolytica genome greatly improved our understanding of these mechanisms. Three main applications of this metabolism will be discussed. The first class corresponds to bioconver-sion processes for the production of secondary metabolites (citric acid), of aroma ( γ - lactone, green note, epoxy geraniol) and of chemicals (dicarboxylic acids). The second class leads to fine chemical production by enantio separation of pharmaceutical compounds using Y. lipolytica enzymes such as epoxyde hydrolase or lipase. The third one refers to production of Single Cell Oils (SCO) from agriculture feedstock. In addition to its ability to handle hydrophobic substrates, Y. lipolytica has also been recognised as a strong secretor of various proteins such as proteases, lipases, RNases and others. A comprehensive review of recent developments of the Y. lipolytica expression/secretion system will finally be presented.

  11. Quorum sensing: a non-conventional target for antibiotic discovery.

    Science.gov (United States)

    Naik, Varsha; Mahajan, Girish

    2013-10-01

    Quorum sensing (QS) is known to regulate different functions viz. pathogenesis, biofilm formation, and host colonization, along with other functions by regulating bacterial virulence determinants. Therefore, QS is deemed to be an interesting target to modulate pathogenesis. Also, there have been global reports of continuous emergence of antibiotic-resistant microbes; hence, an alternative treatment that compliments antibiotic activity is highly desirable. One such approach is to look for QS inhibitors, which can quench the virulence phenotypes exerted by pathogenic bacteria and compliment antibiotic treatment. In the present study, Pseudomonas aeruginosa strain was used as the model organism which produces three pigments viz. pyocyanin, pyoverdin and pyorubin. Pyocyanin synthesis is reported to be QS dependent and is one of the virulence factors of P. aeruginosa. Hence, we envisage inhibition of pyocyanin pigment would indicate QS inhibition (QSI). Auto-inducers like N-(3-oxododecanoyl)-L-homoserine lactone (OdDHL/3-oxo-C12-HSL) and N-butyryl-L- homoserine lactone (BHL/C4-HSL) were used to enhance the pyocyanin pigment production by the model strain at different doses and time points. BHL, at 25 microM was found to be a better inducer of pyocyanin. Tannic acid (TA) was tested to suppress this pigment synthesis and it was found to be effective when assessed at different time points. About 5.12 mg/mL TA was found to be the optimum concentration at which pyocyanin was inhibited by 77.3%. Thus, we confirm that TA can be used as a QSI, either in its purest form or in the crude form found in various plant species, and could be considered for development to compliment antibiotic therapy.

  12. Studies of Non-Conventional Configuration Closed Electron Drift Thrusters

    Energy Technology Data Exchange (ETDEWEB)

    Y. Raitses; D. Staack; A. Smirnov; A.A. Litvak; L.A. Dorf; T. Graves; and N.J. Fisch

    2001-09-10

    In this paper, we review recent results obtained for segmented electrode and cylindrical Hall thrusters. A low sputtering graphite segmented electrode, placed at the exit of the annular thruster, is shown to affect the plasma potential distribution in the ceramic channel. This effect appears to be correlated with an observed plume reduction compared to a conventional, nonsegmented thruster. In preliminary experiments a 3-cm thruster was operated in the 50-200 W power range. Two operating regimes, stable and oscillating, were observed and investigated.

  13. Quantum Theory From a Non-Conventional Perspective

    Science.gov (United States)

    Schuch, D.

    2017-05-01

    Quantum mechanics is essentially described in terms of complex quantities like wave functions. The interesting point is that phase and amplitude of the complex quantities are not independent of each other, but coupled by some kind of conservation law. This coupling exists in time-independent quantum mechanics as well as in in its time-dependent form. It can be traced back to a reformulation of quantum mechanics in terms of complex nonlinear Riccati equations, where the quadratic term in the latter equation explains the origin of the phase-amplitude coupling. Since realistic physical systems are always in contact with some kind of environment this aspect is also taken into account. It turns out that this dissipative effect can either affect the amplitude or the phase of the complex quantity describing the open quantum system. This suggests a relation between non-unitary transformations and gauge-transformations for these systems. A change of the amplitude also seems to be connected with a second quantum of action for “radial” changes, compared to ħ for “angular” changes, leading to an interpretation of Sommerfeld’s constant.

  14. A non-conventional discontinuous Lagrangian for viscous flow

    Science.gov (United States)

    Scholle, M.; Marner, F.

    2017-02-01

    Drawing an analogy with quantum mechanics, a new Lagrangian is proposed for a variational formulation of the Navier-Stokes equations which to-date has remained elusive. A key feature is that the resulting Lagrangian is discontinuous in nature, posing additional challenges apropos the mathematical treatment of the related variational problem, all of which are resolvable. In addition to extending Lagrange's formalism to problems involving discontinuous behaviour, it is demonstrated that the associated equations of motion can self-consistently be interpreted within the framework of thermodynamics beyond local equilibrium, with the limiting case recovering the classical Navier-Stokes equations. Perspectives for applying the new formalism to discontinuous physical phenomena such as phase and grain boundaries, shock waves and flame fronts are provided.

  15. Effects of electron temperature anisotropy on proton mirror instability evolution

    Science.gov (United States)

    Ahmadi, Narges; Germaschewski, Kai; Raeder, Joachim

    2016-06-01

    Proton mirror modes are large amplitude nonpropagating structures frequently observed in the magnetosheath. It has been suggested that electron temperature anisotropy can enhance the proton mirror instability growth rate while leaving the proton cyclotron instability largely unaffected, therefore causing the proton mirror instability to dominate the proton cyclotron instability in Earth's magnetosheath. Here we use particle-in-cell simulations to investigate the electron temperature anisotropy effects on proton mirror instability evolution. Contrary to the hypothesis, electron temperature anisotropy leads to excitement of the electron whistler instability. Our results show that the electron whistler instability grows much faster than the proton mirror instability and quickly consumes the electron-free energy so that there is no electron temperature anisotropy left to significantly impact the evolution of the proton mirror instability.

  16. Effects of electron temperature anisotropy on proton mirror instability evolution

    CERN Document Server

    Ahmadi, Narges; Raeder, Joachim

    2016-01-01

    Proton mirror modes are large amplitude nonpropagating structures frequently observed in the magnetosheath. It has been suggested that electron temperature anisotropy can enhance the proton mirror instability growth rate while leaving the proton cyclotron instability largely unaffected, therefore causing the proton mirror instability to dominate the proton cyclotron instability in Earth's magnetosheath. Here, we use particle-in-cell simulations to investigate the electron temperature anisotropy effects on proton mirror instability evolution. Contrary to the hypothesis, electron temperature anisotropy leads to excitement of the electron whistler instability. Our results show that the electron whistler instability grows much faster than the proton mirror instability and quickly consumes the electron free energy, so that there is no electron temperature anisotropy left to significantly impact the evolution of the proton mirror instability.

  17. Bernstein instability driven by thermal ring distribution

    Science.gov (United States)

    Yoon, Peter H.; Hadi, Fazal; Qamar, Anisa

    2014-07-01

    The classic Bernstein waves may be intimately related to banded emissions detected in laboratory plasmas, terrestrial, and other planetary magnetospheres. However, the customary discussion of the Bernstein wave is based upon isotropic thermal velocity distribution function. In order to understand how such waves can be excited, one needs an emission mechanism, i.e., an instability. In non-relativistic collision-less plasmas, the only known Bernstein wave instability is that associated with a cold perpendicular velocity ring distribution function. However, cold ring distribution is highly idealized. The present Brief Communication generalizes the cold ring distribution model to include thermal spread, so that the Bernstein-ring instability is described by a more realistic electron distribution function, with which the stabilization by thermal spread associated with the ring distribution is demonstrated. The present findings imply that the excitation of Bernstein waves requires a sufficiently high perpendicular velocity gradient associated with the electron distribution function.

  18. Pathways towards instability in financial networks

    Science.gov (United States)

    Bardoscia, Marco; Battiston, Stefano; Caccioli, Fabio; Caldarelli, Guido

    2017-02-01

    Following the financial crisis of 2007-2008, a deep analogy between the origins of instability in financial systems and complex ecosystems has been pointed out: in both cases, topological features of network structures influence how easily distress can spread within the system. However, in financial network models, the details of how financial institutions interact typically play a decisive role, and a general understanding of precisely how network topology creates instability remains lacking. Here we show how processes that are widely believed to stabilize the financial system, that is, market integration and diversification, can actually drive it towards instability, as they contribute to create cyclical structures which tend to amplify financial distress, thereby undermining systemic stability and making large crises more likely. This result holds irrespective of the details of how institutions interact, showing that policy-relevant analysis of the factors affecting financial stability can be carried out while abstracting away from such details.

  19. Ion sound instability driven by ion beam

    CERN Document Server

    Koshkarov, O; Kaganovich, I D; Ilgisonis, V I

    2014-01-01

    In many natural and laboratory conditions, plasmas are often in the non-equilibrium state due to presence of stationary flows, when one particle species (or a special group, such as group of high energy particles, i.e. beam) is mowing with respect to the other plasma components. Such situations are common for a number of different plasma application such as diagnostics with emissive plasma probes, plasma electronics devices and electric propulsion devices. The presence of plasma flows often lead to the instabilities in such systems and subsequent development of large amplitude perturbations. The goal of this work is to develop physical insights and numerical tools for studies of stability of the excitation of the ion sound waves by the ion beam in the configuration similar to the plasma Pierce diode. This systems, in some limiting cases, reduce to mathematically similar equations originally proposed for Pierce instability. The finite length effect are crucial for this instability which generally belong to the...

  20. Modulational instability arising from collective Rayleigh scattering.

    Science.gov (United States)

    Robb, G R M; McNeil, B W J

    2003-02-01

    It is shown that under certain conditions a collection of dielectric Rayleigh particles suspended in a viscous medium and enclosed in a bidirectional ring cavity pumped by a strong laser field can produce a new modulational instability transverse to the wave-propagation direction. The source of the instability is collective Rayleigh scattering i.e., the spontaneous formation of periodic longitudinal particle-density modulations and a backscattered optical field. Using a linear stability analysis a dispersion relation is derived which determines the region of parameter space in which modulational instability of the backscattered field and the particle distribution occurs. In the linear regime the pump is modulationally stable. A numerical analysis is carried out to observe the dynamics of the interaction in the nonlinear regime. In the nonlinear regime the pump field also becomes modulationally unstable and strong pump depletion occurs.

  1. The Parker Instability in Disk Galaxies

    CERN Document Server

    Rodrigues, Luiz Felippe S; Shukurov, Anvar; Bushby, Paul J; Fletcher, Andrew

    2016-01-01

    We examine the evolution of the Parker instability in galactic disks using 3D numerical simulations. We consider a local Cartesian box section of a galactic disk, where gas, magnetic fields and cosmic rays are all initially in a magnetohydrostatic equilibrium. This is done for different choices of initial cosmic ray density and magnetic field. The growth rates and characteristic scales obtained from the models, as well as their dependences on the density of cosmic rays and magnetic fields, are in broad agreement with previous (linearized, ideal) analytical work. However, this non-ideal instability develops a multi-modal 3D structure, which cannot be quantitatively predicted from the earlier linearized studies. This 3D signature of the instability will be of importance in interpreting observations. As a preliminary step towards such interpretations, we calculate synthetic polarized intensity and Faraday rotation measure maps, and the associated structure functions of the latter, from our simulations; these sug...

  2. Rational Instability in the Natural Coalition Forming

    CERN Document Server

    Vinogradova, Galina

    2012-01-01

    We are investigating a paradigm of instability in coalition forming among countries, which indeed is intrinsic to any collection of individual groups or other social aggregations. Coalitions among countries are formed by the respective attraction or repulsion caused by the historical bond propensities between the countries, which produced an intricate circuit of bilateral bonds. Contradictory associations into coalitions occur due to the independent evolution of the bonds. Those coalitions tend to be unstable and break down frequently. The model extends some features of the physical theory of Spin Glasses. Within the frame of this model, the instability is viewed as a consequence of decentralized maximization processes searching for the best coalition allocations. In contrast to the existing literature, a rational instability is found to result from forecast rationality of countries. Using a general theoretical framework allowing to analyze the countries' decision making in coalition forming, we feature a sys...

  3. INSTABILITY OF GAS/LIQUID COAXIAL JET

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this article the emphasis was given to the discussion of the effects of diameter ratio and swirling on instability character for the gas/liquid coaxial jet used by Liao, et al.[1]. The results indicate that the finite diameter ratio markedly increases the maximum growth rate, the most unstable wavenumber, as well as the cutoff wavenumber. It implies that the finite diameter ratio will lead to the liquid jet breakup length shorter and the liquid drop size smaller. The effect of the swirling jets is much more complex: for the axisymmetric perturbation mode, the swirling enhances the flow stability, for helical perturbation, the dominant instability mode occurs at n<0. And it is found that in long wave region there exists a new kind of instability modes at n=1 that was not mentioned in Liao et al.'s article. For this new mode, there appears a dominated swirling ratio at which the flow has the maximum growth rate.

  4. Metal pad instabilities in liquid metal batteries

    Science.gov (United States)

    Zikanov, Oleg

    2016-11-01

    Strong variations between the electrical conductivities of electrolyte and metal layers in a liquid metal battery indicate the possibility of 'metal pad' instabilities. Deformations of the electrolyte-metal interfaces cause strong perturbations of electric currents, which, hypothetically, can generate Lorentz forces enhancing the deformations. We investigate this possibility using two models: a mechanical analogy and a two-dimensional linearized approximation. It is found that the battery is prone to instabilities of two types. One is similar to the sloshing-wave instability observed in the Hall-Héroult aluminum reduction cells. Another is new and related to the interactions of current perturbations with the azimuthal magnetic field induced by the base current. Financial support was provided by the U.S. National Science Foundation (Grant CBET 1435269).

  5. Magnetic interchange instability of accretion disks

    Science.gov (United States)

    Kaisig, M.; Tajima, T.; Lovelace, R. V. E.

    1992-01-01

    The nonlinear evolution of the magnetic interchange or buoyancy instability of a differentially rotating disk threaded by an ordered vertical magnetic field is investigated. A 2D ideal fluid in the equatorial plane of a central mass in the corotating frame of reference is considered as a model for the disk. If the rotation rate of the disk is Keplerian, the disk is found to be stable. If the vertical magnetic field is sufficiently strong, and the field strength decreases with distance from the central object, and thus the rotation of the disk deviates from Keplerian, if is found that an instability develops. The magnetic flux and disk matter expand outward in certain ranges of azimuth, while disk matter with less magnetic flux moves inward over the remaining range of azimuth, showing a characteristic development of an interchange instability.

  6. Mirror Instability in the Turbulent Solar Wind

    Science.gov (United States)

    Hellinger, Petr; Landi, Simone; Matteini, Lorenzo; Verdini, Andrea; Franci, Luca

    2017-04-01

    The relationship between a decaying strong turbulence and the mirror instability in a slowly expanding plasma is investigated using two-dimensional hybrid expanding box simulations. We impose an initial ambient magnetic field perpendicular to the simulation box, and we start with a spectrum of large-scale, linearly polarized, random-phase Alfvénic fluctuations that have energy equipartition between kinetic and magnetic fluctuations and a vanishing correlation between the two fields. A turbulent cascade rapidly develops, magnetic field fluctuations exhibit a Kolmogorov-like power-law spectrum at large scales and a steeper spectrum at sub-ion scales. The imposed expansion (taking a strictly transverse ambient magnetic field) leads to the generation of an important perpendicular proton temperature anisotropy that eventually drives the mirror instability. This instability generates large-amplitude, nonpropagating, compressible, pressure-balanced magnetic structures in a form of magnetic enhancements/humps that reduce the perpendicular temperature anisotropy.

  7. On stability and instability criteria for magnetohydrodynamics.

    Science.gov (United States)

    Friedlander, Susan; Vishik, Misha M.

    1995-06-01

    It is shown that for most, but not all, three-dimensional magnetohydrodynamic (MHD) equilibria the second variation of the energy is indefinite. Thus the class of such equilibria whose stability might be determined by the so-called Arnold criterion is very restricted. The converse question, namely conditions under which MHD equilibria will be unstable is considered in this paper. The following sufficient condition for linear instability in the Eulerian representation is presented: The maximal real part of the spectrum of the MHD equations linearized about an equilibrium state is bounded from below by the growth rate of an operator defined by a system of local partial differential equations (PDE). This instability criterion is applied to the case of axisymmetric toroidal equilibria. Sufficient conditions for instability, stronger than those previously known, are obtained for rotating MHD. (c) 1995 American Institute of Physics.

  8. Photofluid Instabilities of Hot Stellar Envelopes

    CERN Document Server

    Spiegel, E A; Spiegel, Edward A.; Tao, Louis

    1999-01-01

    Beginning from a relatively simple set of dynamical equations for a fluid permeated by a radiative field strong enough to produce significant forces, we find the structure of plane-parallel equilibria and study their stability to small acoustic disturbances. In doing this, we neglect viscous effects and complications of nongreyness. We find that acoutic instabilities occur over a wide range of conditions below the Eddington limit. This result is in line with findings reported twenty years ago but it contradicts some more recent reports of the absence of instabilities. We briefly attempt to identify the causes of the discrepancies and then close with a discussion of the possible astrophysical interest of such instabilities.

  9. Control and simulation of thermoacoustic instabilities

    Science.gov (United States)

    Poinsot, Thierry

    2014-11-01

    Combustion instabilities (CI), due to thermoacoustic coupling between acoustic waves and chemical reaction, constitute a major danger for all combustion systems. They can drive the system to unstable states where the whole combustor can oscillate, vibrate, quench or in extreme cases explode or burn. Such phenomena are commonly observed in the final phases of development programs, leading to major difficulties and significant additional costs. One of the most famous examples of combustion instabilities is the F1 engine of the Apollo program which required more than 1000 engine tests to obtain a stable regime satisfying all other constraints (performance, ignition, etc). CIs constitute one of the most challenging problems in fluid mechanics: they combine turbulence, acoustics, chemistry, unsteady two-phase flow in complex geometries. Since combustion instabilities have been identified (more than hundred years ago), the combustion community has followed two paths: (1) improve our understanding of the phenomena controlling stability to build engines which would be ``stable by design'' and (2) give up on a detailed understanding of mechanisms and add control systems either in open or closed loop devices to inhibit unstable modes. Of course, understanding phenomena driving combustion instabilities to suppress them would be the most satisfying approach but there is no fully reliable theory or numerical method today which can predict whether a combustor will be stable or not before it is fired. This talk will present an overview of combustion instabilities phenomenology before focusing on: (1) active control methods for combustion instabilities and (2) recent methods to predict unstable modes in combustors. These methods are based on recent Large Eddy Simulation codes for compressible reacting flows on HPC systems but we will also describe recent fully analytical methods which provide new insights into unstable modes in annular combustion chambers. Support: European

  10. Arthroscopic Findings in Anterior Shoulder Instability

    Science.gov (United States)

    Hantes, Michael; Raoulis, Vasilios

    2017-01-01

    Background: In the last years, basic research and arthroscopic surgery, have improved our understanding of shoulder anatomy and pathology. It is a fact that arthroscopic treatment of shoulder instability has evolved considerably over the past decades. The aim of this paper is to present the variety of pathologies that should be identified and treated during shoulder arthroscopy when dealing with anterior shoulder instability cases. Methods: A review of the current literature regarding arthroscopic shoulder anatomy, anatomic variants, and arthroscopic findings in anterior shoulder instability, is presented. In addition, correlation of arthroscopic findings with physical examination and advanced imaging (CT and MRI) in order to improve our understanding in anterior shoulder instability pathology is discussed. Results: Shoulder instability represents a broad spectrum of disease and a thorough understanding of the pathoanatomy is the key for a successful treatment of the unstable shoulder. Patients can have a variety of pathologies concomitant with a traditional Bankart lesion, such as injuries of the glenoid (bony Bankart), injuries of the glenoid labrum, superiorly (SLAP) or anteroinferiorly (e.g. anterior labroligamentous periosteal sleeve avulsion, and Perthes), capsular lesions (humeral avulsion of the glenohumeral ligament), and accompanying osseous-cartilage lesions (Hill-Sachs, glenolabral articular disruption). Shoulder arthroscopy allows for a detailed visualization and a dynamic examination of all anatomic structures, identification of pathologic findings, and treatment of all concomitant lesions. Conclusion: Surgeons must be well prepared and understanding the normal anatomy of the glenohumeral joint, including its anatomic variants to seek for the possible pathologic lesions in anterior shoulder instability during shoulder arthroscopy. Patient selection criteria, improved surgical techniques, and implants available have contributed to the enhancement of

  11. INTRINSIC INSTABILITY OF THE LATTICE BGK MODEL

    Institute of Scientific and Technical Information of China (English)

    熊鳌魁

    2002-01-01

    Based on the stability analysis with no linearization and expansion,it is argued that instability in the lattice BGK model is originated from the linearrelaxation hypothesis of collision in the model. The hypothesis stands up only whenthe deviation from the local equilibrium is weak. In this case the computation is abso-lutely stable for real fluids. But for flows of high Reynolds number, this hypothesis isviolated and then instability takes place physically. By performing a transformationa quantified stability criteria is put forward without those approximation. From thecriteria a sufficient condition for stability can be obtained and serve as an estimationof the limited Reynolds number as high as possible.

  12. Nonlinear evolution of whistler wave modulational instability

    DEFF Research Database (Denmark)

    Karpman, V.I.; Lynov, Jens-Peter; Michelsen, Poul;

    1995-01-01

    The nonlinear evolution of the modulational instability of whistler waves coupled to fast magnetosonic waves (FMS) and to slow magnetosonic waves (SMS) is investigated. Results from direct numerical solutions in two spatial dimensions agree with simplified results from a set of ordinary different......The nonlinear evolution of the modulational instability of whistler waves coupled to fast magnetosonic waves (FMS) and to slow magnetosonic waves (SMS) is investigated. Results from direct numerical solutions in two spatial dimensions agree with simplified results from a set of ordinary...

  13. Transient convective instabilities in directional solidification

    CERN Document Server

    Meca, Esteban

    2010-01-01

    We study the convective instability of the melt during the initial transient in a directional solidification experiment in a vertical configuration. We obtain analytically the dispersion relation, and perform an additional asymptotic expansion for large Rayleigh number that permits a simpler analytical analysis and a better numerical behavior. We find a transient instability, i.e. a regime in which the system destabilizes during the transient whereas the final unperturbed steady state is stable. This could be relevant to growth mode predictions in solidification.

  14. Relativistic Cyclotron Instability in Anisotropic Plasmas

    Science.gov (United States)

    López, Rodrigo A.; Moya, Pablo S.; Navarro, Roberto E.; Araneda, Jaime A.; Muñoz, Víctor; Viñas, Adolfo F.; Alejandro Valdivia, J.

    2016-11-01

    A sufficiently large temperature anisotropy can sometimes drive various types of electromagnetic plasma micro-instabilities, which can play an important role in the dynamics of relativistic pair plasmas in space, astrophysics, and laboratory environments. Here, we provide a detailed description of the cyclotron instability of parallel propagating electromagnetic waves in relativistic pair plasmas on the basis of a relativistic anisotropic distribution function. Using plasma kinetic theory and particle-in-cell simulations, we study the influence of the relativistic temperature and the temperature anisotropy on the collective and noncollective modes of these plasmas. Growth rates and dispersion curves from the linear theory show a good agreement with simulations results.

  15. Composition driven structural instability in perovskite ferroelectrics

    Directory of Open Access Journals (Sweden)

    Chao Xu

    2017-04-01

    Full Text Available Ferroelectric solid solutions usually exhibit enhanced functional properties at the morphotropic phase boundary separating two ferroelectric phases with different orientations of polarization. The underlying mechanism is generally associated with polarization rotational instability and the flattened free energy profile. In this work we show that the polarization extensional instability can also be induced at the morphotropic phase boundary beyond the reported polar-nonpolar phase boundary. The piezoelectricity enhanced by this mechanism exhibits excellent thermal stability, which helps to develop high performance piezoelectric materials with good temperature stability.

  16. White-light parametric instabilities in plasmas.

    Science.gov (United States)

    Santos, J E; Silva, L O; Bingham, R

    2007-06-08

    Parametric instabilities driven by partially coherent radiation in plasmas are described by a generalized statistical Wigner-Moyal set of equations, formally equivalent to the full wave equation, coupled to the plasma fluid equations. A generalized dispersion relation for stimulated Raman scattering driven by a partially coherent pump field is derived, revealing a growth rate dependence, with the coherence width sigma of the radiation field, scaling with 1/sigma for backscattering (three-wave process), and with 1/sigma1/2 for direct forward scattering (four-wave process). Our results demonstrate the possibility to control the growth rates of these instabilities by properly using broadband pump radiation fields.

  17. The Farley Instability: A Laboratory Test

    DEFF Research Database (Denmark)

    D'Angelo, N.; Pécseli, Hans; Petersen, P. I.

    1974-01-01

    An experiment is described that was performed in an alkali plasma (Cs) device in order to test the theory of the Farley instability. With υ E×B > Cs (the speed of sound) and νι ≳ ω cι (ν e ≪ ω ce ) wave excitation occurs, the waves traveling normal to the magnetic field B at the υ E×B speed....... The perturbations are strongly elongated along the B field lines, with λ∥ ≫ λ⊥. A comparison with theoretical predictions is given for the observed excitation conditions of the instability....

  18. Streaming instability in negative ion plasma

    Science.gov (United States)

    Kumar, Ajith; Mathew, Vincent

    2017-09-01

    The streaming instability in an unmagnetized negative ion plasma has been studied by computational and theoretical methods. A one dimensional electrostatic Particle In Cell Simulation and fluid dynamical description of negative ion plasma showed that, if the positive ions are having a relative streaming velocity, four different wave modes corresponding to Langmuir wave, fast and slow ion waves and ion acoustic waves are produced. Below a critical wave number, instead of two distinct fast and slow ion waves, we observed a coupled wave mode. The value of the critical wave number is strongly determined by the ion streaming velocity. The thermal velocities of electrons and ions influence the growth rate of instability.

  19. Theory of electrohydrodynamic instabilities in electrolytic cells

    Science.gov (United States)

    Bruinsma, R.; Alexander, S.

    1990-01-01

    The paper develops the theory of the hydrodynamic stability of an electrolytic cell as a function of the imposed electric current. A new electrohydrodynamic instability is encountered when the current is forced to exceed the Nernst limit. The convection is driven by the volume force exerted by the electric field on space charges in the electrolyte. This intrinsic instability is found to be easily masked by extrinsic convection sources such as gravity or stirring. A linear stability analysis is performed and a dimensionless number Le is derived whose value determines the convection pattern.

  20. Instabilities in numerical loop quantum cosmology

    CERN Document Server

    Rosen, J; Khanna, G; Jung, Jae-Hun; Khanna, Gaurav; Rosen, Jessica

    2006-01-01

    In this article we perform von Neumann analysis of the difference equations that arise as a result of loop quantum gravity being applied to models of cosmology and black holes. In particular, we study the numerical stability of Bianchi I LRS (symmetric and non-symmetric constraint) and Schwarzschild interior (symmetric constraint) models, and find that there exist domains over which there are instabilities, generically. We also present explicit evolutions of wave-packets in these models and clearly demonstrate the presence of these instabilities.

  1. Combustion instability mitigation by magnetic fields

    Science.gov (United States)

    Jocher, Agnes; Pitsch, Heinz; Gomez, Thomas; Bonnety, Jérôme; Legros, Guillaume

    2017-06-01

    The present interdisciplinary study combines electromagnetics and combustion to unveil an original and basic experiment displaying a spontaneous flame instability that is mitigated as the non-premixed sooting flame experiences a magnetic perturbation. This magnetic instability mitigation is reproduced by direct numerical simulations to be further elucidated by a flow stability analysis. A key role in the stabilization process is attributed to the momentum and thermochemistry coupling that the magnetic force, acting mainly on paramagnetic oxygen, contributes to sustain. The spatial local stability analysis based on the numerical simulations shows that the magnetic field tends to reduce the growth rates of small flame perturbations.

  2. An instability in neutron stars at birth

    Science.gov (United States)

    Burrows, Adam; Fryxell, Bruce A.

    1992-01-01

    Calculations with a two-dimensional hydrodynamic simulation show that a generic Raleigh-Taylor-like instability occurs in the mantles of nascent neutron stars, that it is possibly violent, and that the standard spherically symmetric models of neutron star birth and supernova explosion may be inadequate. Whether this 'convective' instability is pivotal to the supernova mechanism, pulsar nagnetic fields, or a host of other important issues that attend stellar collapse remains to be seen, but its existence promises to modify all questions concerning this most energetic of astronomical phenomena.

  3. Plasma instabilities in high electric fields

    DEFF Research Database (Denmark)

    Morawetz, K.; Jauho, Antti-Pekka

    1994-01-01

    We analyze nonequilibrium screening with nonequilibrium Green function techniques. By employing the generalized Kadanoff-Baym ansatz to relate the correlation function to the nonequilibrium distribution function, the latter of which is assumed to be a shifted Maxwellian, an analytically tractable...... expression is derived for the nonequilibrium dielectric function epsilon(K, omega). For certain values of momenta K and frequency omega, Imepsilon(K, omega) becomes negative, implying a plasma instability. This new instability exists only for strong electric fields, underlining its nonequilibrium origin....

  4. A fast beam-ion instability

    Energy Technology Data Exchange (ETDEWEB)

    Stupakov, G.V. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1996-08-01

    The ionization of residual gas by an electron beam in an accelerator generates ions that can resonantly couple to the beam through a wave propagating in the beam-ion system. Results of the study of a beam-ion instability are presented for a multi-bunch train taking into account the decoherence of ion oscillations due to the ion frequency spread and spatial variation of the ion frequency. It is shown that the combination of both effects can substantially reduce the growth rate of the instability. (author)

  5. Metal pad instabilities in liquid metal batteries

    CERN Document Server

    Zikanov, Oleg

    2015-01-01

    A mechanical analogy is used to analyze the interaction between the magnetic field, electric current and deformation of interfaces in liquid metal batteries. It is found that, during charging or discharging, a sufficiently large battery is prone to instabilities of two types. One is similar to the metal pad instability known for aluminum reduction cells. Another type is new. It is related to the destabilizing effect of the Lorentz force formed by the azimuthal magnetic field induced by the base current and the current perturbations caused by the local variations of the thickness of the electrolyte layer.

  6. Early Prevention Method for Power Systems Instability

    DEFF Research Database (Denmark)

    Dmitrova, Evgenia

    In the scope of this work, a method capable of fast identification of the proper countermeasure, that prevents emerging instability, has been developed. The focus is placed on the prevention of aperiodic small signal angular instability by means of manipulations applied to load nodes (nodes conta......’s evolution to self-curing systems, for which the human factor involved in control, will keep diminishing....... and defines which amount of countermeasure would be sufficient to bring a critical generator to the stable operation. The early prevention method is addressing the possibility of near real time analysis, utilizing computationally efficient algorithms. The method is providing efficient countermeasure matching...

  7. Managing incontinence due to detrusor instability.

    Science.gov (United States)

    2001-08-01

    Urinary incontinence affects around 3.5 million people of all ages in the UK. For many, incontinence severely restricts their routine activities and damages their quality of life and self-esteem. In about one-third of women sufferers, and around a half of all men with incontinence, the cause is detrusor instability. This condition is characterised by involuntary bladder contractions or pressure rises during bladder filling, which result in a strong or uncontrollable urge to pass urine and, often, incontinence. Here, we consider a primary care-based approach to managing urinary incontinence in adults, concentrating on the medical management of detrusor instability.

  8. THREE-BEAM INSTABILITY IN THE LHC*

    CERN Document Server

    Burov, A

    2013-01-01

    In the LHC, a transverse instability is regularly observed at 4TeV right after the beta-squeeze, when the beams are separated by about their ten transverse rms sizes [1-3], and only one of the two beams is seen as oscillating. So far only a single hypothesis is consistent with all the observations and basic concepts, one about a third beam - an electron cloud, generated by the two proton beams in the high-beta areas of the interaction regions. The instability results from a combined action of the cloud nonlinear focusing and impedance.

  9. Low energy ghosts and the Jeans' instability

    Science.gov (United States)

    Gümrükçüoǧlu, A. Emir; Mukohyama, Shinji; Sotiriou, Thomas P.

    2016-09-01

    We show that a massless canonical scalar field minimally coupled to general relativity can become a tachyonic ghost at low energies around a background in which the scalar's gradient is spacelike. By performing a canonical transformation we demonstrate that this low energy ghost can be recast, at the level of the action, in a form of a fluid that undergoes a Jeans-like instability affecting only modes with large wavelength. This illustrates that low energy tachyonic ghosts do not lead to a catastrophic quantum vacuum instability, unlike the usual high-energy ghost degrees of freedom.

  10. Efficiency Versus Instability in Plasma Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Lebedev, Valeri [Fermilab; Burov, Alexey [Fermilab; Nagaitsev, Sergei [Fermilab

    2017-01-05

    Plasma wake-field acceleration in a strongly nonlinear (a.k.a. the blowout) regime is one of the main candidates for future high-energy colliders. For this case, we derive a universal efficiency-instability relation, between the power efficiency and the key instability parameter of the witness bunch. We also show that in order to stabilize the witness bunch in a regime with high power efficiency, the bunch needs to have high energy spread, which is not presently compatible with collider-quality beam properties. It is unclear how such limitations could be overcome for high-luminosity linear colliders.

  11. Dissipation-induced instabilities and symmetry

    Institute of Scientific and Technical Information of China (English)

    Oleg N. Kirillov; Ferdinand Verhulst

    2011-01-01

    The paradox of destabilization of a conservative or non-conservative system by small dissipation, or Ziegler's paradox (1952), has stimulated a growing interest in the sensitivity of reversible and Hamiltonian systems with respect to dissipative perturbations. Since the last decade it has been widely accepted that dissipation-induced instabilities are closely related to singularities arising on the stability boundary, associated with Whitney's umbrella. The first explanation of Ziegler's paradox was given (much earlier) by Oene Bottema in 1956. The aspects of the mechanics and geometry of dissipation-induced instabilities with an application to rotor dynamics are discussed.

  12. Stream instabilities in relativistically hot plasma

    CERN Document Server

    Shaisultanov, Rashid; Eichler, David

    2011-01-01

    The instabilities of relativistic ion beams in a relativistically hot electron background are derived for general propagation angles. It is shown that the Weibel instability in the direction perpendicular to the streaming direction is the fastest growing mode, and probably the first to appear, consistent with the aligned filaments that are seen in PIC simulations. Oblique, quasiperpendicular modes grow almost as fast, as the growth rate varies only moderately with angle, and they may distort or corrugate the filaments after the perpendicular mode saturates.

  13. Polyhedral (in-)stability of protein crystals

    Science.gov (United States)

    Nanev, Christo N.; Penkova, Anita N.

    2002-04-01

    The polyhedral (in-)stability of monoclinic hen-egg white lysozyme (HEWL) crystals, grown by means of PEG-6000, and that of orthorhombic trypsin crystals has been investigated experimentally. On the basis of a quantitative theoretical analysis, it is compared with the polyhedral (in-)stability of tetragonal HEWL and cubic ferritin crystals. The unambiguous conclusion is that the phenomenon is due to the diffusive supply of matter. This conclusion is also supported by the fact that the phenomenon has common features for both proteins and small molecular crystals.

  14. Methods for Simulating the Heavy Core Instability

    Directory of Open Access Journals (Sweden)

    Chang Philip

    2013-04-01

    Full Text Available Vortices have been proposed as the sites of planet formation, where dust collects and grows into planetesimals, the building blocks of planets. However, for very small dust particles that can be treated as a pressure-less fluid, we have recently discovered the “heavy core” instability, driven by the density gradient in the vortex. In order to understand the eventual outcome of this instability, we need to study its non-linear development. Here, we describe our ongoing work to develop highly accurate numerical models of a vortex with a density gradient embedded within a protoplanetary disk.

  15. Influence of Helium in Gravitational Instabilities

    Science.gov (United States)

    Corona-Galindo, M. G.; Cardona, O.; Klapp, J.

    1990-11-01

    RESUMEN. Hemos analizado los modos hid rod inamicos de un modelo de fluido de dos componentes (hidr6geno y helio), y hemos obtenido la condici6n de inestabilidad para masas mayores que 1.39 veces la bien conocida masa dejeans. ABSTRACT, We have analysed the hydrodynamical modes of a two component fluid model (hydrogen and helium), and we have obtained the instability condition for masses greater than 1.39 times the well-known Jeans mass. K words: COSMOLOGY - GRAVITATION - INSTABILITIES

  16. 鱼骨图分析法在提高急性尿潴留导尿成功率中的应用%The Application of Fishbone Diagram Analysis in Improving the Success Rate of Catheterization for Acute Urinary Retention

    Institute of Scientific and Technical Information of China (English)

    陈桂英

    2014-01-01

    目的:探讨鱼骨图分析法在导尿中的应用。方法:选取2012年2-12月急性尿潴留患者104例作为对照组,使用常规方法导尿;另选取2013年2-12月急性尿潴留患者117例作为观察组,采用鱼骨图分析法进行导尿。观察比较两组的导尿成功率。结果:对照组有95例导尿成功,成功率91.35%;观察组中114例导尿成功,成功率97.44%,观察组的导尿成功率明显高于对照组,差异有统计学意义(χ2=3.98,P<0.05)。结论:鱼骨图分析法能直观反映出急性尿潴留患者导尿失败原因,是提高导尿成功率的有效手段。%To investigate the application of fishbone diagram analysis in catheterization.Method:104 patients with acute urinary retention from February 2012 to December 2012 were selected as the control group,which were given the conventional catheterization,and 117 patients with acute urinary retention from February 2013 to December 2013 were selected as the observation group,they were given the fishbone diagram analysis method for urethral catheterization.The success rate of catheterization between the two groups were observed and compared.Result:There were 95 cases in the control group achieved success in catheterization,the success rate was 91.35%.While there were 114 cases succeeded in the observation group,the success rate was 97.44%.The success rate of catheterization was significantly higher than that of the control group,the difference was statistically significant( χ2=3.98,P<0.05). Conclusion:Fishbone diagram can directly reflect the reasons of failure to perform urethral catheterization in patients with acute urinary retention.It is an effective means to improve the success rate of urethral catheterization.

  17. Selective hemiepiphyseodesis for patellar instability with associated genu valgum.

    Science.gov (United States)

    Kearney, Sean P; Mosca, Vincent S

    2015-03-01

    Patellar instability limits activity and promotes arthritis. Correcting genu valgum with selective hemiepiphyseodesis can treat patellar instability. We retrospectively reviewed 26 knees with patellar instability and associated genu valgum that underwent hemiepiphyseodesis. Average anatomic lateral distal femoral angle (aLDFA) significantly corrected. Symptoms improved in all patients. All competitive athletes returned to sports. One complication occurred. In genu valgum, the patella seeks an abnormal mechanical axis, resulting in patellar instability. By correcting the mechanical axis with hemiepiphyseodesis, patellar instability symptoms improve and patients return to sports. Complications are rare. Selective hemiepiphyseodesis is recommended when treating patellar instability with associated genu valgum.

  18. Genomic instability and cancer: an introduction

    Institute of Scientific and Technical Information of China (English)

    Zhiyuan Shen

    2011-01-01

    @@ Genomic instability as a major driving force of tumorigenesis.The ultimate goal of cell division for most non-cancerous somatic cells is to accurately duplicate the genome and then evenly divide the duplicated genome into the two daughter cells.This ensures that the daughter cells will have exactly the same genetic material as their parent cell.

  19. Final State of Gregory-Laflamme Instability

    CERN Document Server

    Lehner, Luis

    2011-01-01

    We describe the behavior of a perturbed 5-dimensional black string subject to the Gregory-Laflamme instability. We show that the horizon evolves in a self-similar manner, where at any moment in the late-time development of the instability the horizon can be described as a sequence of 3-dimensional spherical black holes of varying size, joined by black string segments of similar radius. As with the initial black string, each local string segment is itself unstable, and this fuels the self-similar cascade to (classically) arbitrarily small scales; in the process the horizon develops a fractal structure. In finite asymptotic time, the remaining string segments shrink to zero-size, yielding a naked singularity. Since no fine-tuning is required to excite the instability, this constitutes a generic violation of cosmic censorship. We further discuss how this behavior is related to satellite formation in low-viscosity fluid streams subject to the Rayleigh-Plateau instability, and estimate the fractal dimension of the...

  20. Instabilities of soft films on compliant substrates

    Science.gov (United States)

    Holland, M. A.; Li, B.; Feng, X. Q.; Kuhl, E.

    2017-01-01

    Instabilities in bilayered systems can generate a wide variety of patterns ranging from simple folds, wrinkles, and creases to complex checkerboards, hexagons, and herringbones. Physics-based theories traditionally model these systems as a thin film on a thick substrate under confined compression and assume that the film is orders of magnitude stiffer than the substrate. However, instability phenomena in soft films on soft substrates remain insufficiently understood. Here we show that soft bilayered systems are highly sensitive to the stiffness ratio, boundary conditions, and mode of compression. In a systematic analysis over a wide range of stiffness ratios, from 0.1 domain compression, substrate prestretch, and film growth, we observe significantly different instability characteristics in the low-stiffness-contrast regime, for β domain compression are unstable for a wide range of wrinkling modes, under film-only compression, the same systems display distinct wrinkling modes.Strikingly, these discrepancies disappear when using measures of effective strain, effective stiffness, and effective wavelength. Our study suggests that future instability studies should use these effective measures to standardize their findings. Our results have important applications in soft matter and living matter physics, where stiffness contrasts are low and small environmental changes can have large effects on morphogenesis, pattern tabselection, and the evolution of shape.

  1. Electronegative Plasma Instabilities in Industrial Pulsed Plasmas

    Science.gov (United States)

    Pribyl, Patrick; Hansen, Anders; Gekelman, Walter

    2016-10-01

    Electronegative gases that are important for industrial etch processes have a series of instabilities that occur at process relevant conditions. These have been studied since the 1990s, but are becoming a much more important today as plasma reactors are being pushed to produce ever finer features, and tight control of the etch process is becoming crucial. The experiments are being done in a plasma etch tool that closely simulates a working industrial device. ICP coils in different configurations are driven by a pulsed RF generators operating at 2-5 MHz. A computer controlled automated probe drive can access a volume above the substrate. The probe can be a Langmuir probe, a ``Bdot'' probe, or an emissive probe the latter used for more accurate determination of plasma potential. A microwave interferometer is available to measure line-averaged electron density. The negative ion instability is triggered depending upon the gas mix (Ar,SF6) , pressure and RF power. The instability can be ``burned through'' by rapidly pulsing the RF power. In this study we present measurements of plasma current and density distribution over the wafer before, after and during the rapid onset of the instability. Work suported by NSF-GOALI Award and done at the BAPSF.

  2. Upstream and Downstream Influence in STBLI Instability

    Science.gov (United States)

    Martin, Pino; Priebe, Stephan; Helm, Clara

    2016-11-01

    Priebe and Martín (JFM, 2012) show that the low-frequency unsteadiness in shockwave and turbulent boundary layer interactions (STBLI) is governed by an inviscid instability. Priebe, Tu, Martín and Rowley (JFM, 2016) show that the instability is an inviscid centrifugal one, i.e Görtlerlike vortices. Previous works had given differing conclusions as to whether the low-frequency unsteadiness in STBLI is caused by an upstream or downstream mechanism. In this paper, we reconcile these opposite views and show that upstream and downstream correlations co-exist in the context of the nature of Görtler vortices. We find that the instability is similar to that in separated subsonic and laminar flows. Since the turbulence is modulated but passive to the global mode, the turbulent separated flows are amenable to linear global analysis. As such, the characteristic length and time scales, and the receptivity of the global mode might be determined, and low-order models that represent the low-frequency dynamics in STBLI might be developed. The centrifugal instability persists even under hypersonic conditions. This work is funded by the AFOSR Grant Number AF9550-15-1-0284 with Dr. Ivett Leyva.

  3. FLARE FLAME INSTABILITY AND BURNER COMBUSTION CONTROL

    OpenAIRE

    БОНДАРЕНКО А.В.; В. Э. Волков; Максимов, М. В.

    2014-01-01

    Research of the flare instability development and the laminar-to-turbulent transition for the flares was executed. It was proved that the effects of viscosity and compressibility have the stabilizing influence on the gas flame. The study of the individual flare stability makes the theoretical basis of the fuel burning technology in combustion chambers and for the burner combustion control.

  4. Genome organization, instabilities, stem cells, and cancer

    Directory of Open Access Journals (Sweden)

    Senthil Kumar Pazhanisamy

    2009-01-01

    Full Text Available It is now widely recognized that advances in exploring genome organization provide remarkable insights on the induction and progression of chromosome abnormalities. Much of what we know about how mutations evolve and consequently transform into genome instabilities has been characterized in the spatial organization context of chromatin. Nevertheless, many underlying concepts of impact of the chromatin organization on perpetuation of multiple mutations and on propagation of chromosomal aberrations remain to be investigated in detail. Genesis of genome instabilities from accumulation of multiple mutations that drive tumorigenesis is increasingly becoming a focal theme in cancer studies. This review focuses on structural alterations evolve to raise a variety of genome instabilities that are manifested at the nucleotide, gene or sub-chromosomal, and whole chromosome level of genome. Here we explore an underlying connection between genome instability and cancer in the light of genome architecture. This review is limited to studies directed towards spatial organizational aspects of origin and propagation of aberrations into genetically unstable tumors.

  5. Theory and Experiments on Chemical Instabilities.

    Science.gov (United States)

    1983-12-31

    following institutions and conferences: 1981 Jan. 8 X Reunion de Fisica Estadistica , Cocoyoc, Mexico, Resonances and Control Features Feb. 13 Michigan State...Aeronautics and Astronautics, Invited Remarks, Palo Alto, CA 1982 Feb. 25,26 Industrial Affiliates Program ": .’ Hydrodynamic and Chemical Instabilities

  6. Laboratory experiments on arc deflection and instability

    Energy Technology Data Exchange (ETDEWEB)

    Zweben, S.; Karasik, M.

    2000-03-21

    This article describes experiments on arc deflection instability carried out during the past few years at the Princeton University Plasma Physics Laboratory (PPPL). The approach has been that of plasma physicists interested in arcs, but they believe these results may be useful to engineers who are responsible for controlling arc behavior in large electric steel furnaces.

  7. Pattern formation - Instabilities in sand ripples

    DEFF Research Database (Denmark)

    Hansen, J. L.; v. Hecke, M.; Haaning, A.

    2001-01-01

    Sand ripples are seen below shallow wavy water and are formed whenever water oscillates over a bed of sand. Here we analyse the instabilities that can upset this perfect patterning when the ripples are subjected to large changes in driving amplitude or frequency, causing them to deform both...

  8. Nonlinear parametric instability of wind turbine wings

    DEFF Research Database (Denmark)

    Larsen, Jesper Winther; Nielsen, Søren R.K.

    2006-01-01

    Nonlinear rotor dynamic is characterized by parametric excitation of both linear and nonlinear terms caused by centrifugal and Coriolis forces when formulated in a moving frame of reference. Assuming harmonically varying support point motions from the tower, the nonlinear parametric instability...

  9. Rossby Wave Instability of Keplerian Accretion Disks

    CERN Document Server

    Lovelace, R V E; Colgate, S A; Nelson, A F

    1999-01-01

    We find a linear instability of non-axisymmetric Rossby waves in a thin non-magnetized Keplerian disk when there is a local maximum in the radial profile of a key function ${\\cal L}(r) \\equiv {\\cal F}(r) S^{2/\\Gamma}(r)$, where ${\\cal F}^{-1} = \\hat {\\bf z}\\cdot ({\\bf \

  10. Perception and self-organised instability

    Directory of Open Access Journals (Sweden)

    Karl eFriston

    2012-07-01

    Full Text Available This paper considers state-dependent dynamics that mediate perception in the brain. In particular, it considers the formal basis of self-organised instabilities that enable perceptual transitions during Bayes-optimal perception. The basic phenomena we consider are perceptual transitions that lead to conscious ignition (Dehaene & Changeux, 2011 and how they depend on dynamical instabilities that underlie chaotic itinerancy (Tsuda, 2001; Breakspear, 2001 and self-organised criticality (Shew, Yang, Yu, Roy, & Plenz, 2011; Plenz & Thiagarajan, 2007; Beggs & Plenz, 2003. Our approach is based on a dynamical formulation of perception as approximate Bayesian inference, in terms of variational free energy minimisation. This formulation suggests that perception has an inherent tendency to induce dynamical instabilities (critical slowing that enable the brain to respond sensitively to sensory perturbations. We briefly review the dynamics of perception, in terms of generalised Bayesian filtering and free energy minimisation, present a formal conjecture about self-organised instability and then test this conjecture, using neuronal (numerical simulations of perceptual categorisation.

  11. Surface instabilities during straining of anisotropic materials

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang; Richelsen, Ann Bettina

    2006-01-01

    The development of instabilities in traction-free surfaces is investigated numerically using a unit cell model. Full finite strain analyses are conducted using isotropic as well as anisotropic yield criteria and both plane strain tension and compression are considered. In the load range of tension...

  12. Kinetic Simulations of Rayleigh-Taylor Instabilities

    CERN Document Server

    Sagert, Irina; Colbry, Dirk; Howell, Jim; Staber, Alec; Strother, Terrance

    2014-01-01

    We report on an ongoing project to develop a large scale Direct Simulation Monte Carlo code. The code is primarily aimed towards applications in astrophysics such as simulations of core-collapse supernovae. It has been tested on shock wave phenomena in the continuum limit and for matter out of equilibrium. In the current work we focus on the study of fluid instabilities. Like shock waves these are routinely used as test-cases for hydrodynamic codes and are discussed to play an important role in the explosion mechanism of core-collapse supernovae. As a first test we study the evolution of a single-mode Rayleigh-Taylor instability at the interface of a light and a heavy fluid in the presence of a gravitational acceleration. To suppress small-wavelength instabilities caused by the irregularity in the separation layer we use a large particle mean free path. The latter leads to the development of a diffusion layer as particles propagate from one fluid into the other. For small amplitudes, when the instability is i...

  13. Mechanisms of cadmium induced genomic instability

    Energy Technology Data Exchange (ETDEWEB)

    Filipic, Metka, E-mail: metka.filipic@nib.si [National Institute of Biology, Department for Genetic Toxicology and Cancer Biology, Ljubljana (Slovenia)

    2012-05-01

    Cadmium is an ubiquitous environmental contaminant that represents hazard to humans and wildlife. It is found in the air, soil and water and, due to its extremely long half-life, accumulates in plants and animals. The main source of cadmium exposure for non-smoking human population is food. Cadmium is primarily toxic to the kidney, but has been also classified as carcinogenic to humans by several regulatory agencies. Current evidence suggests that exposure to cadmium induces genomic instability through complex and multifactorial mechanisms. Cadmium dose not induce direct DNA damage, however it induces increase in reactive oxygen species (ROS) formation, which in turn induce DNA damage and can also interfere with cell signalling. More important seems to be cadmium interaction with DNA repair mechanisms, cell cycle checkpoints and apoptosis as well as with epigenetic mechanisms of gene expression control. Cadmium mediated inhibition of DNA repair mechanisms and apoptosis leads to accumulation of cells with unrepaired DNA damage, which in turn increases the mutation rate and thus genomic instability. This increases the probability of developing not only cancer but also other diseases associated with genomic instability. In the in vitro experiments cadmium induced effects leading to genomic instability have been observed at low concentrations that were comparable to those observed in target organs and tissues of humans that were non-occupationally exposed to cadmium. Therefore, further studies aiming to clarify the relevance of these observations for human health risks due to cadmium exposure are needed.

  14. Mix and hydrodynamic instabilities on NIF

    Science.gov (United States)

    Smalyuk, V. A.; Robey, H. F.; Casey, D. T.; Clark, D. S.; Döppner, T.; Haan, S. W.; Hammel, B. A.; MacPhee, A. G.; Martinez, D.; Milovich, J. L.; Peterson, J. L.; Pickworth, L.; Pino, J. E.; Raman, K.; Tipton, R.; Weber, C. R.; Baker, K. L.; Bachmann, B.; Berzak Hopkins, L. F.; Bond, E.; Caggiano, J. A.; Callahan, D. A.; Celliers, P. M.; Cerjan, C.; Dixit, S. N.; Edwards, M. J.; Felker, S.; Field, J. E.; Fittinghoff, D. N.; Gharibyan, N.; Grim, G. P.; Hamza, A. V.; Hatarik, R.; Hohenberger, M.; Hsing, W. W.; Hurricane, O. A.; Jancaitis, K. S.; Jones, O. S.; Khan, S.; Kroll, J. J.; Lafortune, K. N.; Landen, O. L.; Ma, T.; MacGowan, B. J.; Masse, L.; Moore, A. S.; Nagel, S. R.; Nikroo, A.; Pak, A.; Patel, P. K.; Remington, B. A.; Sayre, D. B.; Spears, B. K.; Stadermann, M.; Tommasini, R.; Widmayer, C. C.; Yeamans, C. B.; Crippen, J.; Farrell, M.; Giraldez, E.; Rice, N.; Wilde, C. H.; Volegov, P. L.; Gatu Johnson, M.

    2017-06-01

    Several new platforms have been developed to experimentally measure hydrodynamic instabilities in all phases of indirect-drive, inertial confinement fusion implosions on National Ignition Facility. At the ablation front, instability growth of pre-imposed modulations was measured with a face-on, x-ray radiography platform in the linear regime using the Hydrodynamic Growth Radiography (HGR) platform. Modulation growth of "native roughness" modulations and engineering features (fill tubes and capsule support membranes) were measured in conditions relevant to layered DT implosions. A new experimental platform was developed to measure instability growth at the ablator-ice interface. In the deceleration phase of implosions, several experimental platforms were developed to measure both low-mode asymmetries and high-mode perturbations near peak compression with x-ray and nuclear techniques. In one innovative technique, the self-emission from the hot spot was enhanced with argon dopant to "self-backlight" the shell in-flight. To stabilize instability growth, new "adiabat-shaping" techniques were developed using the HGR platform and applied in layered DT implosions.

  15. On cavitation instabilities with interacting voids

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2012-01-01

    voids so far apart that the radius of the plastic zone around each void is less than 1% of the current spacing between the voids, can still affect each others at the occurrence of a cavitation instability such that one void stops growing while the other grows in an unstable manner. On the other hand...

  16. Instabilities in power law gradient hardening materials

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2005-01-01

    Tension and compression instabilities are investigated for specimens with dimensions in the micron range. A finite strain generalization of a higher order strain gradient plasticity theory is implemented in a finite element scheme capable of modeling power law hardening materials. Effects...

  17. Study of Fast Instability in Fermilab Recycler

    Energy Technology Data Exchange (ETDEWEB)

    Antipov, Sergey [Chicago U.; Adamson, Philip [Fermilab; Nagaitsev, Sergei [Fermilab; Yang, Ming-Jen [Fermilab

    2016-06-01

    One of the factors which may limit the intensity in the Fermilab Recycler is a fast transverse instability. It develops within a hundred turns and, in certain conditions, may lead to a beam loss. Various peculiar features of the instability: its occurrence only above a certain intensity threshold, and only in horizontal plane, as well as the rate of the instability, suggest that its cause is electron cloud. We studied the phenomena by observing the dynamics of stable and unstable beam. We found that beam motion can be stabilized by a clearing bunch, which confirms the electron cloud nature of the instability. The findings suggest electron cloud trapping in Recycler combined function mag-nets. Bunch-by-bunch measurements of betatron tune show a tune shift towards the end of the bunch train and allow the estimation of the density of electron cloud and the rate of its build-up. The experimental results are in agreement with numerical simulations of electron cloud build-up and its interaction with the beam.

  18. Modelling Fluidelastic Instability Forces in Tube Arrays

    Science.gov (United States)

    Anderson, J. Burns

    Historically, heat exchangers have been among the most failure prone components in nuclear power plants. Most of these failures are due to tube failures as a result of corrosion, fatigue and fretting wear. Fatigue and fretting wear are a result of flow induced vibration through turbulent buffeting and fluidelastic instability mechanisms. Fluidelastic instability is by far the most important and complex mechanism. This research deals with modelling fluidelastic instability and the resulting tube response. The proposed time domain model uses the concept of a flow cell (Hassan & Hayder [16]) to represent the complex flow field inside a shell and tube heat exchanger and accounts for temporal variations in the flow separation points as a result of tube motion. The fluidelastic forces are determined by predicting the attachment lengths. The predicted forces are used to simulate the response of a single flexible tube inside a shell and tube heat exchanger. It was found that accounting for temporal variations in the separation points predicted lower critical flow velocities, than that of fixed attachment and separation points. Once unstable a phase lag is predicted between the fluidelastic forces and tube response. It was determined that the predicted critical flow velocities agreed well with available experimental data. The developed model represents an important step towards a realistic fluidelastic instability model which can be used to design the new generation nuclear steam generators.

  19. Modulational instability in periodic quadratic nonlinear materials

    DEFF Research Database (Denmark)

    Corney, Joel Frederick; Bang, Ole

    2001-01-01

    We investigate the modulational instability of plane waves in quadratic nonlinear materials with linear and nonlinear quasi-phase-matching gratings. Exact Floquet calculations, confirmed by numerical simulations, show that the periodicity can drastically alter the gain spectrum but never complete...

  20. Nonlinear parametric instability of wind turbine wings

    DEFF Research Database (Denmark)

    Larsen, Jesper Winther; Nielsen, Søren R.K.

    2006-01-01

    Nonlinear rotor dynamic is characterized by parametric excitation of both linear and nonlinear terms caused by centrifugal and Coriolis forces when formulated in a moving frame of reference. Assuming harmonically varying support point motions from the tower, the nonlinear parametric instability o...

  1. Longitudinal Single Bunch Instability Study on BEPCII

    CERN Document Server

    Dou, Wang; Zhe, Duan; Na, Wang; Li, Wang; Lin, Wang; Jie, Gao

    2013-01-01

    In order to study the single bunch longitudinal instability in BEPCII, experiments on the positron ring (BPR) for the bunch lengthening phenomenon were made. By analyzing the experimental data based on Gao's theory, the longitudinal loss factor for the bunch are obtained. Also, the total wake potential and the beam current threshold are estimated.

  2. Regional Educational Inequality and Political Instability.

    Science.gov (United States)

    Monchar, Philip Harris

    1981-01-01

    From a study of 46 nations over the period 1957 to 1973, it is argued that regional educational inequality indicates the presence of other regional social, political, and economic inequalities, and it is all of these factors together that generate feelings of relative deprivation and the pursuant political instability. (Author/SJL)

  3. Political instability and country risk : new evidence

    NARCIS (Netherlands)

    DeHaan, J; Siermann, CLJ; VanLubek, E

    1997-01-01

    This note presents new estimates of a probit model for the debt rescheduling, using a sample of 65 countries over the period 1984-93. Apart from economic variables, a whole range of indicators for political instability are included in the model as explanatory variables. It turns out, that none is si

  4. Fisher Information, Sustainability, Development and Political Instability

    Science.gov (United States)

    Fisher information is a measure of order inherent in the timer series data for any dynamic system. We have computed the Fisher Information for nation-states using the data from 1960 to 1997 from the State Instability Task Force. We find that nation-states fall into two categories...

  5. Collisionless shock waves mediated by Weibel Instability

    Science.gov (United States)

    Naseri, Neda; Ruan, Panpan; Zhang, Xi; Khudik, Vladimir; Shvets, Gennady

    2015-11-01

    Relativistic collisionless shocks are common events in astrophysical environments. They are thought to be responsible for generating ultra-high energy particles via the Fermi acceleration mechanism. It has been conjectured that the formation of collisionless shocks is mediated by the Weibel instability that takes place when two initially cold, unmagnetized plasma shells counter-propagate into each other with relativistic drift velocities. Using a PIC code, VLPL, which is modified to suppress numerical Cherenkov instabilities, we study the shock formation and evolution for asymmetric colliding shells with different densities in their own proper reference frame. Plasma instabilities in the region between the shock and the precursor are also investigated using a moving-window simulation that advances the computational domain at the shock's speed. This method helps both to save computation time and avoid severe numerical Cherenkov instabilities, and it allows us to study the shock evolution in a longer time period. Project is supported by US DOE grants DE-FG02-04ER41321 and DE-FG02-07ER54945.

  6. Nonlinear Kinetic Dynamics of Magnetized Weibel Instability

    CERN Document Server

    Palodhi, L; Pegoraro, F

    2010-01-01

    Kinetic numerical simulations of the evolution of the Weibel instability during the full nonlinear regime are presented. The formation of strong distortions in the electron distribution function resulting in formation of strong peaks in it and their influence on the resulting electrostatic waves are shown.

  7. Jeans instability in classical and modified gravity

    Directory of Open Access Journals (Sweden)

    E.V. Arbuzova

    2014-12-01

    Full Text Available Gravitational instability in classical Jeans theory, General Relativity, and modified gravity is considered. The background density increase leads to a faster growth of perturbations in comparison with the standard theory. The transition to the Newtonian gauge in the case of coordinate dependent background metric functions is studied. For modified gravity a new high frequency stable solution is found.

  8. Jeans instability in classical and modified gravity

    Energy Technology Data Exchange (ETDEWEB)

    Arbuzova, E.V., E-mail: arbuzova@uni-dubna.ru [Novosibirsk State University, Novosibirsk, 630090 (Russian Federation); Department of Higher Mathematics, University “Dubna”, 141980 Dubna (Russian Federation); Dolgov, A.D., E-mail: dolgov@fe.infn.it [Novosibirsk State University, Novosibirsk, 630090 (Russian Federation); ITEP, Bol. Cheremushkinsaya ul., 25, 113259 Moscow (Russian Federation); Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Polo Scientifico e Tecnologico – Edificio C, Via Saragat 1, 44122 Ferrara (Italy); Reverberi, L., E-mail: reverberi@fe.infn.it [Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Polo Scientifico e Tecnologico – Edificio C, Via Saragat 1, 44122 Ferrara (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Ferrara, Polo Scientifico e Tecnologico – Edificio C, Via Saragat 1, 44122 Ferrara (Italy)

    2014-12-12

    Gravitational instability in classical Jeans theory, General Relativity, and modified gravity is considered. The background density increase leads to a faster growth of perturbations in comparison with the standard theory. The transition to the Newtonian gauge in the case of coordinate dependent background metric functions is studied. For modified gravity a new high frequency stable solution is found.

  9. Gravitational Instability of a Nonrotating Galaxy

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Alexander W.; /SLAC

    2005-12-14

    Gravitational instability of the distribution of stars in a galaxy is a well-known phenomenon in astrophysics. This work is a preliminary attempt to analyze this phenomenon using the standard tools developed in accelerator physics. By applying this analysis, it is found that a stable nonrotating galaxy would become unstable if its size exceeds a certain limit that depends on its mass density.

  10. Morphological instabilities of stratified epithelia: a mechanical instability in tumour formation

    CERN Document Server

    Risler, Thomas

    2013-01-01

    Interfaces between stratified epithelia and their supporting stromas commonly exhibit irregular shapes. Undulations are particularly pronounced in dysplastic tissues and typically evolve into long, finger-like protrusions in carcinomas. In a previous work (Basan et al., Phys. Rev. Lett. 106, 158101 (2011)), we demonstrated that an instability arising from viscous shear stresses caused by the constant flow due to cell turnover in the epithelium could drive this phenomenon. While interfacial tension between the two tissues as well as mechanical resistance of the stroma tend to maintain a flat interface, an instability occurs for sufficiently large viscosity, cell-division rate and thickness of the dividing region in the epithelium. Here, extensions of this work are presented, where cell division in the epithelium is coupled to the local concentration of nutrients or growth factors diffusing from the stroma. This enhances the instability by a mechanism similar to that of the Mullins-Sekerka instability in single...

  11. Termination of the magnetorotational instability via parasitic instabilities in core-collapse supernovae

    CERN Document Server

    Rembiasz, Tomasz; Cerdá-Durán, Pablo; Müller, Ewald; Aloy, Miguel-Ángel

    2015-01-01

    The magnetorotational instability (MRI) can be a powerful mechanism amplifying the magnetic field in core collapse supernovae. However, whether initially weak magnetic fields can be amplified by this instability to dynamically relevant strengths is still a matter of active scientific debate. One of the main uncertainties concerns the process that terminates the growth of the instability. Parasitic instabilities of both Kelvin-Helmholtz (KH) and tearing-mode type have been suggested to play a crucial role in this process, disrupting MRI channel flows and quenching magnetic field amplification. We performed two-dimensional and three-dimensional sheering-disc simulations of a differentially rotating proto-neutron star layer in non-ideal MHD with unprecedented high numerical resolution. Our simulations show that KH parasitic modes dominate tearing modes in the regime of large hydrodynamic and magnetic Reynolds numbers, as encountered in proto-neutron stars. They also determine the maximum magnetic field stress ac...

  12. Corona-induced electrohydrodynamic instabilities in low conducting liquids

    Energy Technology Data Exchange (ETDEWEB)

    Vega, F.; Perez, A.T. [Depto. Electronica y Electromagnetismo, Facultad de Fisica, Universidad de Sevilla, Avda. Reina Mercedes, s/n. 41012, Sevilla (Spain)

    2003-06-01

    The rose-window electrohydrodynamic (EHD) instability has been observed when a perpendicular field with an additional unipolar ion injection is applied onto a low conducting liquid surface. This instability has a characteristic pattern with cells five to 10 times greater than those observed in volume instabilities caused by unipolar injection. We have used corona discharge from a metallic point to perform some measurements of the rose-window instability in low conducting liquids. The results are compared to the linear theoretical criterion for an ohmic liquid. They confirmed that the minimum voltage for this instability is much lower than that for the interfacial instability in high conducting liquids. This was predicted theoretically in the dependence of the critical voltage as a function of the non-dimensional conductivity. It is shown that in a non-ohmic liquid the rose window appears as a secondary instability after the volume instability. (orig.)

  13. The subcritical baroclinic instability in local accretion disc models

    CERN Document Server

    Lesur, G

    2009-01-01

    (abridged) Aims: We present new results exhibiting a subcritical baroclinic instability (SBI) in local shearing box models. We describe the 2D and 3D behaviour of this instability using numerical simulations and we present a simple analytical model describing the underlying physical process. Results: A subcritical baroclinic instability is observed in flows stable for the Solberg-Hoiland criterion using local simulations. This instability is found to be a nonlinear (or subcritical) instability, which cannot be described by ordinary linear approaches. It requires a radial entropy gradient weakly unstable for the Schwartzchild criterion and a strong thermal diffusivity (or equivalently a short cooling time). In compressible simulations, the instability produces density waves which transport angular momentum outward with typically alpha<3e-3, the exact value depending on the background temperature profile. Finally, the instability survives in 3D, vortex cores becoming turbulent due to parametric instabilities...

  14. Estimating the Number of Clusters via Normalized Cluster Instability

    OpenAIRE

    Haslbeck, Jonas M. B.; Wulff, Dirk U.

    2016-01-01

    We improve existing instability-based methods for the selection of the number of clusters $k$ in cluster analysis by normalizing instability. In contrast to existing instability methods which only perform well for bounded sequences of small $k$, our method performs well across the whole sequence of possible $k$. In addition, we compare for the first time model-based and model-free variants of $k$ selection via cluster instability and find that their performance is similar. We make our method ...

  15. A Computational Study of Transverse Combustion Instability Mechanisms

    Science.gov (United States)

    2014-07-01

    Marshall Space Flight Center. References 1. Smith, D. A., Zukoski, E. E., “Combustion Instability Sustained by Unsteady Vortex Combustion,” 21st JPC ...Prediction in a Model Rocket Combustor,” 47th JPC , AIAA 2011-6030. 10. Harvazinski, M. E., Modeling Self-Excited Combustion Instabilities Using A...Instabilities,” 49th JPC , AIAA 2013-3992. 13. Smith, R., Xia, G., Anderson, W., Merkle, C. L., “Extraction of Combustion Instability Mechanisms form Detailed

  16. Helicobacter pylori infection generates genetic instability in gastric cells

    DEFF Research Database (Denmark)

    Machado, Ana Manuel; Figueiredo, C.; Seruca, R.

    2010-01-01

    The discovery that Helicobacter pylori is associated with gastric cancer has led to numerous studies that investigate the mechanisms by which H. pylori induces carcinogenesis. Gastric cancer shows genetic instability both in nuclear and mitochondrial DNA, besides impairment of important DNA repair...... of the host, such as oxidative damage, methylation, chromosomal instability, microsatellite instability, and mutations. Interestingly, H. pylori infection generates genetic instability in nuclear and mitochondrial DNA. Based on the reviewed literature we conclude that H. pylori infection promotes gastric...

  17. Essays on political instability: Measurement, causes and consequences

    OpenAIRE

    Jong-A-Pin, R.

    2008-01-01

    In political economy, the concept of political instability plays a prominent role as it raises uncertainty with respect to future institutions and economic policies, thereby affecting the incentives of e.g. households, firms, and politicians. This dissertation contains four quantitative studies on the measurement , causes and consequences of political instability. The research questions that are addressed are: how should political instability be measured? Does political instability hamper eco...

  18. TRANSMISSION LINE-WIRE DANCING (GALLOPING) – LYAPUNOV INSTABILITY

    OpenAIRE

    V. I. Vanko; I. K. Marchevski

    2014-01-01

    This article describes aerodynamic losses of damping, or aerodynamic instability, which we observe in experiments and in engineering practice. As applied to industrial high-voltage lines this phenomenon is usually called galloping (dancing) of phase line wires. This phenolmenon can be explained by Lyapunov’s instability of equilibrium state of wires profile (cross-section). In addition to known condition of Grauert-den-Hartog’s instability there was obtained practical condition of instability...

  19. Analysis of Instabilities in Non-Equilibrium Plasmas

    Institute of Scientific and Technical Information of China (English)

    LIN Lie; WU Bin; ZHANG Peng; WANG Yong-Qing

    2004-01-01

    Plasma instabilities with charged particle production processes in non-equilibrium plasma are analysed. A criterion on plasma instabilities is deduced by first-order perturbation theory. The relationship between plasma instabilities and certain factors (degree of non-equilibrium in plasma, the electron attachment rate coefficient and electron temperature) are described.

  20. Subwavelength modulational instability and plasmon oscillons in nanoparticle arrays

    CERN Document Server

    Noskov, Roman E; Kivshar, Yuri S; 10.1103/PhysRevLett.108.093901

    2012-01-01

    We study modulational instability in nonlinear arrays of subwavelength metallic nanoparticles, and analyze numerically nonlinear scenarios of the instability development. We demonstrate that modulational instability can lead to the formation of regular periodic or quasi-periodic modulations of the polarization. We reveal that such nonlinear nanoparticle arrays can support long-lived standing and moving oscillating nonlinear localized modes - plasmon oscillons.

  1. Electromechanical instabilities of thermoplastics: Theory and in situ observation

    OpenAIRE

    Wang, Qiming; Niu, Xiaofan; Pei, Qibing; Michael D. Dickey; Zhao, Xuanhe

    2012-01-01

    Thermoplastics under voltages are used in diverse applications ranging from insulating cables to organic capacitors. Electromechanical instabilities have been proposed as a mechanism that causes electrical breakdown of thermoplastics. However, existing experiments cannot provide direct observations of the instability process, and existing theories for the instabilities generally assume thermoplastics are mechanically unconstrained. Here, we report in situ observations of electromechanical ins...

  2. On the measurement of political instability and its impact on economic growth

    NARCIS (Netherlands)

    Jong-A-Pin, R.

    We examine the multidimensionality of political instability using 25 political instability indicators in an Exploratory Factor Analysis. We find that political instability has four dimensions: politically motivated violence, mass civil protest. instability within the political regime. and

  3. On the measurement of political instability and its impact on economic growth

    NARCIS (Netherlands)

    Jong-A-Pin, R.

    2009-01-01

    We examine the multidimensionality of political instability using 25 political instability indicators in an Exploratory Factor Analysis. We find that political instability has four dimensions: politically motivated violence, mass civil protest. instability within the political regime. and instabilit

  4. Electron cloud instability in high intensity proton rings

    Directory of Open Access Journals (Sweden)

    K. Ohmi

    2002-11-01

    Full Text Available An e^{-}p instability has been observed in some proton rings. The instability, which causes beam loss, limits the performance of the ring. The instability may be serious for 3 and 50 GeV proton storage rings in the Japan Proton Accelerator Research Complex (J-PARC. We study the e^{-}p instability in several high intensity proton storage rings operated in the world. This work informs J-PARC of the necessity to cure the instability, for example, by applying a TiN coating on the chamber surface.

  5. Drift Kelvin-Helmholtz instabilities in space plasmas

    Science.gov (United States)

    Sharma, Avadhesh C.; Srivastava, Krishna M.

    1992-01-01

    Drift Kelvin-Helmholtz instabilities of a finite-beta plasma in equilibrium electric and magnetic fields which are perpendicular to each other are studied using two fluid equations. Three types of these instabilities are considered including the magnetosonic instability of a finite beta-homogeneous plasma, the electrostatic drift instability of an inhomogeneous low-beta plasma, and the magneto-acoustic instability of a high-beta inhomogeneous isothermal plasma. It is shown that the electric field has either stabilizing or destabilizing effect depending on conditions under consideration.

  6. Kelvin-Helmholtz versus Hall magnetoshear instability in astrophysical flows.

    Science.gov (United States)

    Gómez, Daniel O; Bejarano, Cecilia; Mininni, Pablo D

    2014-05-01

    We study the stability of shear flows in a fully ionized plasma. Kelvin-Helmholtz is a well-known macroscopic and ideal shear-driven instability. In sufficiently low-density plasmas, also the microscopic Hall magnetoshear instability can take place. We performed three-dimensional simulations of the Hall-magnetohydrodynamic equations where these two instabilities are present, and carried out a comparative study. We find that when the shear flow is so intense that its vorticity surpasses the ion-cyclotron frequency of the plasma, the Hall magnetoshear instability is not only non-negligible, but it actually displays growth rates larger than those of the Kelvin-Helmholtz instability.

  7. Modulation Instability in Biased Photorefractive-Photovoltaic Crystals

    Institute of Scientific and Technical Information of China (English)

    LU Ke-Qing; ZHAO Wei; YANG Yan-Long; SUN Chuan-Dong; GAO Hong-Wen; LI Jin-Ping; ZHANG Yan-Peng

    2004-01-01

    @@ We show the modulation instability of broad optical beams in biased photorefractive-photovoltaic crystals under steady-state conditions. This modulation instability growth rate depends on the external bias field, the bulk photovoltaic effect, and the ratio of the optical beam intensity to that of the dark irradiance. Under appropriate conditions, this modulation instability growth rate is the modulation instability growth rate studied previously in biased photorefractive-nonphotovoltaic crystals, and the modulation instability growth rate in open- and closed-circuit photorefractive-photovoltaic crystals can be predicted.

  8. Buckling Instability in Liquid Crystalline Physical Gels

    Science.gov (United States)

    Verduzco, Rafael; Meng, Guangnan; Kornfield, Julia A.; Meyer, Robert B.

    2006-04-01

    In a nematic gel we observe a low-energy buckling deformation arising from soft and semisoft elastic modes. We prepare the self-assembled gel by dissolving a coil side-group liquid-crystalline polymer coil copolymer in a nematic liquid crystal. The gel has long network strands and a precisely tailored structure, making it ideal for studying nematic rubber elasticity. Under polarized optical microscopy we observe a striped texture that forms when gels uniformly aligned at 35 °C are cooled to room temperature. We model the instability using the molecular theory of nematic rubber elasticity, and the theory correctly captures the change in pitch length with sample thickness and polymer concentration. This buckling instability is a clear example of a low-energy deformation that arises in materials where polymer network strains are coupled to the director orientation.

  9. Electromagnetic instability induced by Neutrino interaction

    CERN Document Server

    Bhatt, Jitesh R

    2016-01-01

    A kinetic theory of spin plasma in a neutrino background is developed. Equations of motion of a charged particle in the presence of electromagnetic field and the neutrino asymmetry are derived using the effective low-energy Lagrangian. Modified Vlasov equation is obtained by extending the regular phase-space to incorporate the spin degree of freedom. We apply this formalism to the early Universe to study collective modes in the plasma after the neutrino decoupling. It is shown that the parity violating term in the Lagrangian leads to a plasma instability which can generate magnetic fields. We find that that at the temperatures below the neutrino decoupling the instability can produce magnetic field of 10 Gauss in the Universe. We discuss cosmological implications of the results.

  10. A Joint Chow Test for Structural Instability

    Directory of Open Access Journals (Sweden)

    Bent Nielsen

    2015-03-01

    Full Text Available The classical Chow test for structural instability requires strictly exogenousregressors and a break-point specified in advance. In this paper, we consider twogeneralisations, the one-step recursive Chow test (based on the sequence of studentisedrecursive residuals and its supremum counterpart, which relaxes these requirements. We useresults on the strong consistency of regression estimators to show that the one-step test isappropriate for stationary, unit root or explosive processes modelled in the autoregressivedistributed lags (ADL framework. We then use the results in extreme value theory to developa new supremum version of the test, suitable for formal testing of structural instability withan unknown break-point. The test assumes the normality of errors and is intended to be usedin situations where this can be either assumed nor established empirically. Simulations showthat the supremum test has desirable power properties, in particular against level shifts latein the sample and against outliers. An application to U.K. GDP data is given.

  11. The natural progression of scaphoid instability.

    Science.gov (United States)

    Watson, H K; Weinzweig, J; Zeppieri, J

    1997-02-01

    Wrist injury or repeated wrist sprains probably result in injury to the scapholunate ligament more commonly than previously recognized, which may allow abnormal scaphoid skid under load. This results in a common clinical entity termed DWS. Scaphoid instability is a spectrum condition ranging from minor, asymptomatic findings (seen in 20% of normal adults) through symptomatic findings in patients with normal radiographs to abnormal instability on radiographs, to degenerative change, and, ultimately, to SLAC wrist (see Fig. 1). Appropriate diagnosis and management of each of these wrist disorders are highly dependent upon a keen understanding of normal periscaphoid anatomy as well as the anatomic derangements that occur within the wrist that predispose a given patient to subsequent degenerative changes. With that understanding, the appropriateness of conservative therapy, SL exploration and arthroplasty, ligament repair, triscaphe arthrodesis, or SLAC reconstruction can be readily determined in each case.

  12. Mathematical modelling on instability of shear fault

    Institute of Scientific and Technical Information of China (English)

    范天佑

    1996-01-01

    A study on mathematical modelling on instability of fault is reported.The fracture mechanics and fracture dynamics as a basis of the discussion,and the method of complex variable function (including the conformal mapping and approximate conformal mapping) are employed,and some analytic solutions of the problem in closed form are found.The fault body concept is emphasized and the characteristic size of fault body is introduced.The effect of finite size of the fault body and the effect of the fault propagating speed (especially the effect of the high speed) and their influence on the fault instability are discussed.These results further explain the low-stress drop phenomena observed in earthquake source.

  13. Kluger's "fixateur interne" for spinal instability.

    Science.gov (United States)

    Sandvoss, G; Feldmann, H

    1991-01-01

    Kluger's "Fixateur Interne" proved to be an excellent tool not only in spinal trauma for repositioning of impacted fractures and transpedicular stabilization of the dorsal column but also in other forms of thoracic or lumbar instability. After spinal tumor excision from a dorsal approach and vertebral replacement with methylmethacrylate additional stability through dorsal fixation was achieved with this device. Spondylodiscitis, symptomatic spondylolisthesis, spinal instability from degenerative disc disease as well as "non-union" following previous surgery could be cured using Kluger's internal fixation. Rare complications, i.e. from broken screws or rods (5%) caused no problems, but some patients required a second operation for readjustment of malpositioned screws which were causing pain or neurological deficit.

  14. Diffusive MHD Instabilities: Beyond the Chandrasekhar Theorem

    CERN Document Server

    Ruediger, Guenther; Stefani, Frank; Mond, Michael

    2014-01-01

    The magnetohydrodynamic stability of axially unbounded cylindrical flows is considered which contain a toroidal magnetic background field with the same radial profile as the linear azimuthal velocity. Chandrasekhar (1956) has shown for ideal fluids the stability of this configuration if the Alfven velocity of the field equals the velocity of the background flow. It is demonstrated for magnetized Taylor-Couette flows at the Rayleigh line, however, that for finite diffusivity such flows become unstable against nonaxisymmetric perturbations where the critical magnetic Reynolds number of the rotation rate does not depend on the magnetic Prandtl number Pm if Pm much << 1. In order to study this new diffusive azimuthal magnetorotational instability, flows and fields with the same radial profile but with different amplitudes are considered. For Pm << 1 the instability domain with the weakest fields and the slowest rotation rates lies below the Chandrasekhar line of equal amplitudes for Alfven velocity an...

  15. General Theory of the Plasmoid Instability

    CERN Document Server

    Comisso, L; Huang, Y -M; Bhattacharjee, A

    2016-01-01

    A general theory of the onset and development of the plasmoid instability is formulated by means of a principle of least time. The scaling relations for the final aspect ratio, transition time to rapid onset, growth rate, and number of plasmoids are derived, and shown to depend on the initial perturbation amplitude $\\left({\\hat w}_0\\right)$, the characteristic rate of current sheet evolution $\\left(1/\\tau\\right)$, and the Lundquist number $\\left(S\\right)$. They are not simple power laws, and are proportional to $S^{\\alpha} \\tau^{\\beta} \\left[\\ln f(S,\\tau,{\\hat w}_0)\\right]^\\sigma$. The detailed dynamics of the instability is also elucidated, and shown to comprise of a period of quiescence followed by sudden growth over a short time scale.

  16. Feedback control of coupled-bunch instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Fox, J.D.; Eisen, N.; Hindi, H.; Linscott, I.; Oxoby, G.; Sapozhnikov, L. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Serio, M. [Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati

    1993-05-01

    The next generation of synchrotron light sources and particle accelerators will require active feedback systems to control multi-bunch instabilities. Stabilizing hundreds or thousands of potentially unstable modes in these accelerator designs presents many technical challenges. Feedback systems to stabilize coupled-bunch instabilities may be understood in the frequency domain (mode-based feedback) or in the time domain (bunch-by-bunch feedback). In both approaches an external amplifier system is used to create damping fields that prevent coupled-bunch oscillations from growing without bound. The system requirements for transverse (betatron) and longitudinal (synchrotron) feedback are presented, and possible implementation options developed. Feedback system designs based on digital signal-processing techniques are described. Experimental results are shown from a synchrotron oscillation damper in the SSRL/SLAC storage ring SPEAR that uses digital signal-processing techniques.

  17. Dissipative drift instability in dusty plasma

    Directory of Open Access Journals (Sweden)

    Nilakshi Das

    2012-03-01

    Full Text Available An investigation has been done on the very low-frequency electrostatic drift waves in a collisional dusty plasma. The dust density gradient is taken perpendicular to the magnetic field B0⃗, which causes the drift wave. In this case, low-frequency drift instabilities can be driven by E1⃗×B0⃗ and diamagnetic drifts, where E1⃗ is the perturbed electric field. Dust charge fluctuation is also taken into consideration for our study. The dust- neutral and ion-neutral collision terms have been included in equations of motion. It is seen that the low-frequency drift instability gets damped in such a system. Both dust charging and collision of plasma particles with the neutrals may be responsible for the damping of the wave. Both analytical and numerical techniques have been used while developing the theory.

  18. Deployment Instabilities of Lobed-Pumpkin Balloon

    Science.gov (United States)

    Nakashino, Kyoichi

    A lobed-pumpkin balloon, currently being developed in ISAS/JAXA as well as in NASA, is a promising vehicle for long duration scientific observations in the stratosphere. Recent ground and flight experiments, however, have revealed that the balloon has deployment instabilities under certain conditions. In order to overcome the instability problems, a next generation SPB called 'tawara' type balloon has been proposed, in which an additional cylindrical part is appended to the standard lobed-pumpkin balloon. The present study investigates the deployment stability of tawara type SPB in comparison to that of standard lobed-pumpkin SPB through eigenvalue analysis on the basis of finite element methods. Our numerical results show that tawara type SPB enjoys excellent deployment performance over the standard lobed-pumpkin SPBs.

  19. Transverse Mode Coupling Instability with Space Charge

    CERN Document Server

    Balbekov, V

    2016-01-01

    Transverse mode coupling instability of a bunch with space charge and wake field is considered in frameworks of the boxcar model. Eigenfunctions of the bunch without wake are used as the basis for solution of the equations with the wake field included. Dispersion equation for the bunch eigentunes is obtained in the form of an infinite continued fraction. It is shown that influence of space charge on the instability essentially depends on the wake sign. In particular, threshold of the negative wake increases in absolute value until the space charge tune shift is rather small, and goes to zero at higher space charge. The explanation of this behavior is developed by analysis of the bunch spectrum. A comparison of the results with published articles is represented.

  20. ALE simulation of Rayleigh-Taylor instability

    Energy Technology Data Exchange (ETDEWEB)

    Anbarlooei, H.R. [Univ. of Science and Technology, Dept. of Mechanical Engineering, Tehran (Iran, Islamic Republic of); Mazaheri, K. [Univ. of Tarbiyat Modares, Dept. of Mechanical Engineering, Tehran, (Iran, Islamic Republic of)]. E-mail: Kiumars@modares.ac.ir; Bidabadi, M. [Univ. of Science and Technology, Dept. of Mechanical Engineering, Tehran (Iran, Islamic Republic of)

    2004-07-01

    This paper investigates the use of an Arbitrary Lagrangian-Eulerian (ALE) technique for the simulation of a single mode Rayleigh-Taylor instability. A compatible Lagrangian algorithm is used on a simply connected quadrilateral grid in Lagrangian Phase. This algorithm includes subzonal pressures, which are used to control spurious grid motion, and an edge centered artificial viscosity. We use Reference Jacobians optimization based rezone algorithm in the rezoning phase of ALE method. Also a second order sign preserving method is used for remapping. To force monotonocity in remapping phase a Repair algorithm is used. Finally, for remapping of nodal variables we used a second order transformer to transfer these data to cell centers. It is shown that the usage of these algorithms for an ALE method can improve the simulation of a single mode Rayleigh-Taylor Instability. (author)

  1. Elastic instability in stratified core annular flow.

    Science.gov (United States)

    Bonhomme, Oriane; Morozov, Alexander; Leng, Jacques; Colin, Annie

    2011-06-01

    We study experimentally the interfacial instability between a layer of dilute polymer solution and water flowing in a thin capillary. The use of microfluidic devices allows us to observe and quantify in great detail the features of the flow. At low velocities, the flow takes the form of a straight jet, while at high velocities, steady or advected wavy jets are produced. We demonstrate that the transition between these flow regimes is purely elastic--it is caused by the viscoelasticity of the polymer solution only. The linear stability analysis of the flow in the short-wave approximation supplemented with a kinematic criterion captures quantitatively the flow diagram. Surprisingly, unstable flows are observed for strong velocities, whereas convected flows are observed for low velocities. We demonstrate that this instability can be used to measure the rheological properties of dilute polymer solutions that are difficult to assess otherwise.

  2. Elastic instability in stratified core annular flow

    CERN Document Server

    Bonhomme, Oriane; Leng, Jacques; Colin, Annie

    2010-01-01

    We study experimentally the interfacial instability between a layer of dilute polymer solution and water flowing in a thin capillary. The use of microfluidic devices allows us to observe and quantify in great detail the features of the flow. At low velocities, the flow takes the form of a straight jet, while at high velocities, steady or advected wavy jets are produced. We demonstrate that the transition between these flow regimes is purely elastic -- it is caused by viscoelasticity of the polymer solution only. The linear stability analysis of the flow in the short-wave approximation captures quantitatively the flow diagram. Surprisingly, unstable flows are observed for strong velocities, whereas convected flows are observed for low velocities. We demonstrate that this instability can be used to measure rheological properties of dilute polymer solutions that are difficult to assess otherwise.

  3. Wakefields and Instabilities in Linear Accelerators

    CERN Document Server

    Ferrario, M; Palumbo, L

    2014-01-01

    When a charged particle travels across the vacuum chamber of an accelerator, it induces electromagnetic fields, which are left mainly behind the generating particle. These electromagnetic fields act back on the beam and influence its motion. Such an interaction of the beam with its surro undings results in beam energy losses, alters the shape of the bunches, and shifts the betatron and synchrotron frequencies. At high beam current the fields can even lead to instabilities, thus limiting the performance of the accelerator in terms of beam quality and current intensity. We discuss in this lecture the general features of the electromagnetic fields, introducing the concepts of wakefields and giving a few simple examples in cylindrical geometry. We then show the effect of the wakefields on the dynamics of a beam in a linac, dealing in particular with the beam breakup instability and how to cure it.

  4. Stochastically driven instability in rotating shear flows

    CERN Document Server

    Mukhopadhyay, Banibrata

    2012-01-01

    Origin of hydrodynamic turbulence in rotating shear flows is investigated. The particular emphasis is the flows whose angular velocity decreases but specific angular momentum increases with increasing radial coordinate. Such flows are Rayleigh stable, but must be turbulent in order to explain observed data. Such a mismatch between the linear theory and observations/experiments is more severe when any hydromagnetic/magnetohydrodynamic instability and then the corresponding turbulence therein is ruled out. The present work explores the effect of stochastic noise on such hydrodynamic flows. We essentially concentrate on a small section of such a flow which is nothing but a plane shear flow supplemented by the Coriolis effect. This also mimics a small section of an astrophysical accretion disk. It is found that such stochastically driven flows exhibit large temporal and spatial correlations of perturbation velocities, and hence large energy dissipations of perturbation, which presumably generate instability. A ra...

  5. Thin film instability with thermal noise

    CERN Document Server

    Diez, Javier A; Fernández, Roberto

    2016-01-01

    We study the effects of stochastic thermal fluctuations on the instability of the free surface of a flat liquid film upon a solid substrate. These fluctuations are represented as a standard Brownian motion that can be added to the deterministic equation for the film thickness within the lubrication approximation. Here, we consider that while the noise term is white in time, it is coloured in space. This allows for the introduction of a finite correlation length in the description of the randomized intermolecular interaction. Together with the expected spatial periodicity of the flow, we find a dimensionless parameter, $\\beta$, that accounts for the relative importance of the spatial correlation. We perform here the linear stability analysis (LSA) of the film under the influence of both terms, and find the corresponding power spectra for the amplitudes of the normal modes of the instability. We compare this theoretical result with the numerical simulations of the complete non-linear problem, and find a good ag...

  6. Explosive Instability of Prominence Flux Ropes

    Energy Technology Data Exchange (ETDEWEB)

    Hurricane, O; Fong, R H L; Cowley, S C

    2002-09-04

    The rapid, Alfvenic, time scale of erupting solar-prominences has been an enigma ever since they where first identified. Investigators have proposed a variety of different mechanisms in an effort to account for the abrupt reconfiguration observed. No one mechanism clearly stands out as the single cause of these explosive events. Recent analysis has demonstrated that field lines in the solar atmosphere are metastable to ballooning type instabilities. It has been found previously that in ideal MHD plasmas marginally unstable ballooning modes inevitably become ''explosive'' evolving towards a finite time singularity via a nonlinear 3D instability called ''Nonlinear Magnetohydrodynamic Detonation.'' Thus, this mechanism is a good candidate to explain explosive events observed in the solar atmosphere of our star or in others.

  7. Fluctuations and correlations in modulation instability

    Science.gov (United States)

    Solli, D. R.; Herink, G.; Jalali, B.; Ropers, C.

    2012-07-01

    Stochastically driven nonlinear processes are responsible for spontaneous pattern formation and instabilities in numerous natural and artificial systems, including well-known examples such as sand ripples, cloud formations, water waves, animal pigmentation and heart rhythms. Technologically, a type of such self-amplification drives free-electron lasers and optical supercontinuum sources whose radiation qualities, however, suffer from the stochastic origins. Through time-resolved observations, we identify intrinsic properties of these fluctuations that are hidden in ensemble measurements. We acquire single-shot spectra of modulation instability produced by laser pulses in glass fibre at megahertz real-time capture rates. The temporally confined nature of the gain physically limits the number of amplified modes, which form an antibunched arrangement as identified from a statistical analysis of the data. These dynamics provide an example of pattern competition and interaction in confined nonlinear systems.

  8. Electromagnetic instabilities in rotating magnetized viscous objects

    CERN Document Server

    Nekrasov, Anatoly

    2009-01-01

    We study electromagnetic streaming instabilities in thermal viscous regions of rotating astrophysical objects, such as, magnetized accretion disks, molecular clouds, their cores, and elephant trunks. The obtained results can also be applied to any regions of interstellar medium, where different equilibrium velocities between charged species can arise. We consider a weakly ionized multicomponent plasma consisting of neutrals and magnetized electrons, ions, and dust grains. The effect of perturbation of collisional frequencies due to density perturbations of species is taken into account. We obtain general expressions for perturbed velocities of species involving the thermal pressure and viscosity in the case in which perturbations propagate perpendicular to the background magnetic field. The dispersion relation is derived and investigated for axisymmetric perturbations. New compressible instabilities generated due to different equilibrium velocities of different charged species are found in the cold and therma...

  9. Patterns and instability of grannular flow

    Energy Technology Data Exchange (ETDEWEB)

    Ecke, Robert E [Los Alamos National Laboratory; Borzsonyi, Tamas [NON LANL; Mcelwaine, Jim N [U. CAMBRIDGE

    2009-01-01

    Dense granular flows are often observed to become unstable and form inhomogeneous structures in nature or industry. Although recently significant advances have been made in understanding simple flows, instabilities are often not understood in detail. We present experimental and numerical results that show the formation of longitudinal stripes. These arise from instability of the uniform flowing state of granular media on a rough inclined plane. The form of the stripes depends critically on the mean density of the flow with a robust form of stripes at high density that consists of fast sliding plug-like regions (stripes) on top of highly agitated boiling material -- a configuration reminiscent of the Leidenfrost effect when a droplet of liquid lifted by its vapor is hovering above a hot surface.

  10. Gravitational Instability and Tsallis' Nonextensive Statistics

    CERN Document Server

    Lima, J A S; Silva, R

    2002-01-01

    The concept of Jeans gravitational instability is rediscussed in the framework of the nonextensive statistics proposed by Tsallis. A simple analytical formula generalizing the Jeans criterion is derived by assuming that the unperturbed self-gravitating collisionless gas is described by the $q$-parametrized class of nonextensive velocity distribution. It is shown that the critical values of wavelenght and mass depend explicitly on the nonextensive $q$-parameter. The standard Jeans wavelenght derived for a Maxwellian distribution is recovered in the limiting case $q$=1. For power-law distributions with cutoff, the instability condition is weakneed with the system becoming unstable even for wavelenghts of the disturbance smaller than the standard Jeans lenght $\\lambda_J$.

  11. Instability in electromagnetically driven flows Part I

    CERN Document Server

    Gissinger, Christophe; Fauve, Stephan

    2016-01-01

    The MHD flow driven by a travelling magnetic field (TMF) in an annular channel is investigated numerically. For sufficiently large magnetic Reynolds number Rm, or if a large enough pressure gradient is externally applied, the system undergoes an instability in which the flow rate in the channel dramatically drops from synchronism with the wave to much smaller velocities. This transition takes the form of a saddle-node bifurcation for the time-averaged quantities. In this first paper, we characterize the bifurcation, and study the stability of the flow as a function of several parameters. We show that the bifurcation of the flow involves a bistability between Poiseuille-like and Hartman-like regimes, and relies on magnetic flux expulsion. Based on this observation, new predictions are made for the occurrence of this stalling instability.

  12. Understanding ionospheric instabilities eludes current approaches

    Science.gov (United States)

    Bhattacharya, Atreyee

    2012-07-01

    Ionized gases are heavily concentrated in the ionosphere's F zone, the region between 200 and 500 kilometers in altitude, which is critical for transmitting long-distance radio signals on Earth. However, instabilities in the F region plasma, which can last from seconds to hours and can be spread over centimeters to tens of kilometers, disrupt transmission of radio signals. The plasma instabilities, restricted to the equatorial region following sunset, are called equatorial spread F (ESF). Earth-based instruments perceive ESF events as “twinkling” radio signals. ESF events, first detected in the 1930s, affect the performance and reliability of space-borne and ground-based electronic systems; they can disrupt satellite operations and related communications and navigation systems.

  13. Microscopic instability in recurrent neural networks

    Science.gov (United States)

    Yamanaka, Yuzuru; Amari, Shun-ichi; Shinomoto, Shigeru

    2015-03-01

    In a manner similar to the molecular chaos that underlies the stable thermodynamics of gases, a neuronal system may exhibit microscopic instability in individual neuronal dynamics while a macroscopic order of the entire population possibly remains stable. In this study, we analyze the microscopic stability of a network of neurons whose macroscopic activity obeys stable dynamics, expressing either monostable, bistable, or periodic state. We reveal that the network exhibits a variety of dynamical states for microscopic instability residing in a given stable macroscopic dynamics. The presence of a variety of dynamical states in such a simple random network implies more abundant microscopic fluctuations in real neural networks which consist of more complex and hierarchically structured interactions.

  14. Thermal instability in the interstellar medium

    Directory of Open Access Journals (Sweden)

    J. Ghanbari

    2000-06-01

    Full Text Available   This study demonstrates how thermal structures in the interstellar medium can emerge as a result of thermal instability. For a two-dimensional case, the steady state thermal structures was investigeted and it was shown that a large class of solutions exist. For a one –dimensional case the conductivity was found to be negligible. The effects of to cal cooling on the thermal instability were explored in some depth. In this case analytical results for time-dependent cooling function were presented, too. We studied nonlinear wave phenomena in thermal fluid systems, with a particular emphasis on presenting analytical results. When conductivity is proportional to temperature, the beliavior of thermal waves is soliton like. For slow thermal waves, approximate analytical results were presented. Extensions of this work are discussed briefly, together with possible astrophysical applications.

  15. Transverse Mode Coupling Instability with Space Charge

    Energy Technology Data Exchange (ETDEWEB)

    Balbekov, V. [Fermilab

    2016-03-11

    Transverse mode coupling instability of a bunch with space charge and wake field is considered in frameworks of the boxcar model. Eigenfunctions of the bunch without wake are used as the basis for solution of the equations with the wake field included. Dispersion equation for the bunch eigentunes is obtained in the form of an infinite continued fraction. It is shown that influence of space charge on the instability essentially depends on the wake sign. In particular, threshold of the negative wake increases in absolute value until the space charge tune shift is rather small, and goes to zero at higher space charge. The explanation of this behavior is developed by analysis of the bunch spectrum. A comparison of the results with published articles is represented.

  16. Semiconductor Lasers Stability, Instability and Chaos

    CERN Document Server

    Ohtsubo, Junji

    2013-01-01

    This third edition of “Semiconductor Lasers, Stability, Instability and Chaos” was significantly extended.  In the previous edition, the dynamics and characteristics of chaos in semiconductor lasers after the introduction of the fundamental theory of laser chaos and chaotic dynamics induced by self-optical feedback and optical injection was discussed. Semiconductor lasers with new device structures, such as vertical-cavity surface-emitting lasers and broad-area semiconductor lasers, are interesting devices from the viewpoint of chaotic dynamics since they essentially involve chaotic dynamics even in their free-running oscillations. These topics are also treated with respect to the new developments in the current edition. Also the control of such instabilities and chaos control are critical issues for applications. Another interesting and important issue of semiconductor laser chaos in this third edition is chaos synchronization between two lasers and the application to optical secure communication. One o...

  17. Baroclinic Instability on Hot Extrasolar Planets

    CERN Document Server

    Polichtchouk, Inna

    2012-01-01

    We investigate baroclinic instability in flow conditions relevant to hot extrasolar planets. The instability is important for transporting and mixing heat, as well as for influencing large-scale variability on the planets. Both linear normal mode analysis and non-linear initial value calculations are carried out -- focusing on the freely-evolving, adiabatic situation. Using a high-resolution general circulation model (GCM) which solves the traditional primitive equations, we show that large-scale jets similar to those observed in current GCM simulations of hot extrasolar giant planets are likely to be baroclinically unstable on a timescale of few to few tens of planetary rotations, generating cyclones and anticyclones that drive weather systems. The growth rate and scale of the most unstable mode obtained in the linear analysis are in qualitative, good agreement with the full non-linear calculations. In general, unstable jets evolve differently depending on their signs (eastward or westward), due to the chang...

  18. Transient Instability of Rapidly Rotating Black Holes

    CERN Document Server

    Gralla, Samuel E; Zimmerman, Peter

    2016-01-01

    We analytically study the linear response of a near-extremal Kerr black hole to external scalar, electromagnetic, and gravitational field perturbations. We show that the energy density, electromagnetic field strength, and tidal force experienced by infalling observers exhibit transient growth near the horizon. The growth lasts arbitrarily long in the extremal limit, reproducing the horizon instability of extremal Kerr. We explain these results in terms of near-horizon geometry and discuss potential astrophysical implications.

  19. APC and chromosome instability in colorectal cancer

    Directory of Open Access Journals (Sweden)

    C. M. Cabrera

    Full Text Available Colon cancer is a common disease that can be sporadic or familial. An inactivated adenomatous polyposis coli (APC suppressor gene is found in over 80% of colorectal tumors, this being an early alteration in the development of adenomatous polyps. APC function is not only critical for tumor initiation and progression, and chromosome instability (CIN is another characteristic dependent at least partly on APC mutations.

  20. Aeroelastic instability stoppers for wind tunnel models

    Science.gov (United States)

    Doggett, R. V., Jr.; Ricketts, R. H. (Inventor)

    1981-01-01

    A mechanism for constraining models or sections thereof, was wind tunnel tested, deployed at the onset of aeroelastic instability, to forestall destructive vibrations in the model is described. The mechanism includes a pair of arms pivoted to the tunnel wall and straddling the model. Rollers on the ends of the arms contact the model, and are pulled together against the model by a spring stretched between the arms. An actuator mechanism swings the arms into place and back as desired.