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Sample records for bubble trauma special

  1. Bubbles

    DEFF Research Database (Denmark)

    Dholakia, Nikhilesh; Turcan, Romeo V.

    2013-01-01

    A goal of our ongoing research stream is to develop a multidisciplinary metatheory of bubbles. In this viewpoint paper we put forward a typology of bubbles by comparing four types of assets – entertainment, commodities, financial securities (stocks), and housing properties – where bubbles could a...

  2. Gas Bubble Trauma Monitoring and Research of Juvenile Salmonids, 1994-1995 Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Hans, Karen M.

    1997-07-01

    This report describes laboratory and field monitoring studies of gas bubble trauma (GBT) in migrating juvenile salmonids in the Snake and Columbia rivers. The first chapter describes laboratory studies of the progression of GBT signs leading to mortality and the use of the signs for GBT assessment. The progression and severity of GBT signs in juvenile salmonids exposed to different levels of total dissolved gas (TDG) and temperatures was assessed and quantified. Next, the prevalence, severity, and individual variation of GBT signs was evaluated to attempt to relate them to mortality. Finally, methods for gill examination in fish exposed to high TDG were developed and evaluated. Primary findings were: (1) no single sign of GBT was clearly correlated with mortality, but many GBT signs progressively worsened; (2) both prevalence and severity of GBT signs in several tissues is necessary; (3) bubbles in the lateral line were the earliest sign of GBT, showed progressive worsening, and had low individual variation but may develop poorly during chronic exposures; (4) fin bubbles had high prevalence, progressively worsened, and may be a persistent sign of GBT; and (5) gill bubbles appear to be the proximate cause of death but may only be relevant at high TDG levels and are difficult to examine. Chapter Two describes monitoring results of juvenile salmonids for signs of GBT. Emigrating fish were collected and examined for bubbles in fins and lateral lines. Preliminary findings were: (1) few fish had signs of GBT, but prevalence and severity appeared to increase as fish migrated downstream; (2) there was no apparent correlation between GBT signs in the fins, lateral line, or gills; (3) prevalence and severity of GBT was suggestive of long-term, non-lethal exposure to relatively low level gas supersaturated water; and (4) it appeared that GBT was not a threat to migrating juvenile salmonids. 24 refs., 26 figs., 3 tabs.

  3. Lateral line pore diameters correlate with the development of gas bubble trauma signs in several Columbia River fishes

    Science.gov (United States)

    Morris, R.G.; Beeman, J.W.; VanderKooi, S.P.; Maule, A.G.

    2003-01-01

    Gas bubble trauma (GBT) caused by gas supersaturation of river water continues to be a problem in the Columbia River Basin. A common indicator of GBT is the percent of the lateral line occluded with gas bubbles; however, this effect has never been examined in relation to lateral line morphology. The effects of 115, 125 and 130% total dissolved gas levels were evaluated on five fish species common to the upper Columbia River. Trunk lateral line pore diameters differed significantly (Plargescale sucker>northern pikeminnow≥chinook salmon≥redside shiner). At all supersaturation levels evaluated, percent of lateral line occlusion exhibited an inverse correlation to pore size but was not generally related to total dissolved gas level or time of exposure. This study suggests that the differences in lateral line pore diameters between species should be considered when using lateral line occlusion as an indicator of gas bubble trauma.

  4. Special Communication Trauma care in Malawi: A call to action

    African Journals Online (AJOL)

    Prehospital trauma care on the scene of an accident— whether that is roadside care after a traffic collision, .... care practices.21 Establishing a trauma registry where none has previously existed is a challenging task.22 .... Jayaraman S, Mabweijano JR, Lipnick MS, Caldwell N, Miyamoto. J, Wangoda R, et al. First things first: ...

  5. Influence of infection with Renibacterium salmoninarum on susceptibility of juvenile spring chinook salmon to gas bubble trauma

    Science.gov (United States)

    Weiland, L.K.; Mesa, M.G.; Maule, A.G.

    1999-01-01

    During experiments in our laboratory to assess the progression and severity of gas bubble trauma (GBT) in juvenile spring chinook salmon Oncorhynchus tshawytscha, we had the opportunity to assess the influence of Renibacterium salmoninarum (Rs), the causative agent of bacterial kidney disease, on the susceptibility of salmon to GBT. We exposed fish with an established infection of Rs to 120% total dissolved gas (TDG) for 96 h and monitored severity of GBT signs in the fins and gills, Rs infection level in kidneys by using an enzyme-linked immunosorbent assay (ELISA), and mortality. Mortality occurred rapidly after exposure to 120% TDG, with a LT20 (time necessary to kill 20% of the population) of about 37 h, which is at a minimum about 16% earlier than other bioassays we have conducted using fish that had no apparent signs of disease. Fish that died early (from 31 to 36 h and from 49 to 52 h) had significantly higher infection levels (mean ?? SE ELISA absorbance = 1.532 ?? 0.108) than fish that survived for 96h (mean ?? SE ELISA absorbance = 0.828 ?? 0.137). Fish that died early also had a significantly greater number of gill filaments occluded with bubbles than those that survived 96 h. Conversely, fish that survived for 96 h had a significantly higher median fin severity ranking than those that died early. Our results indicate that fish with moderate to high levels of Rs infection are more vulnerable to the effects of dissolved gas supersaturation (DGS) and die sooner than fish with lower levels of Rs infection. However, there is a substantial amount of individual variation in susceptibility to the apparent cumulative effects of DGS and Rs infection. Collectively, our findings have important implications to programs designed to monitor the prevalence and severity of GBT in juvenile salmonids in areas like the Columbia River basin and perhaps elsewhere.

  6. Bubble systems

    CERN Document Server

    Avdeev, Alexander A

    2016-01-01

    This monograph presents a systematic analysis of bubble system mathematics, using the mechanics of two-phase systems in non-equilibrium as the scope of analysis. The author introduces the thermodynamic foundations of bubble systems, ranging from the fundamental starting points to current research challenges. This book addresses a range of topics, including description methods of multi-phase systems, boundary and initial conditions as well as coupling requirements at the phase boundary. Moreover, it presents a detailed study of the basic problems of bubble dynamics in a liquid mass: growth (dynamically and thermally controlled), collapse, bubble pulsations, bubble rise and breakup. Special emphasis is placed on bubble dynamics in turbulent flows. The analysis results are used to write integral equations governing the rate of vapor generation (condensation) in non-equilibrium flows, thus creating a basis for solving a number of practical problems. This book is the first to present a comprehensive theory of boil...

  7. Is Trauma Memory Special? Trauma Narrative Fragmentation in PTSD: Effects of Treatment and Response.

    Science.gov (United States)

    Bedard-Gilligan, Michele; Zoellner, Lori A; Feeny, Norah C

    2017-03-01

    Seminal theories posit that fragmented trauma memories are critical to posttraumatic stress disorder (PTSD; van der Kolk & Fisler, 1995; Brewin, 2014) and that elaboration of the trauma narrative is necessary for recovery (e.g., Foa, Huppert, & Cahill, 2006). According to fragmentation theories, trauma narrative changes, particularly for those receiving trauma-focused treatment, should accompany symptom reduction. Trauma and control narratives in 77 men and women with chronic PTSD were examined pre- and post-treatment, comparing prolonged exposure (PE) and sertraline. Utilizing self-report, rater coding, and objective coding of narrative content, fragmentation was compared across narrative types (trauma, negative, positive) by treatment modality and response, controlling for potential confounds. Although sensory components increased with PE (d = 0.23 - 0.44), there were no consistent differences in fragmentation from pre- to post-treatment between PE and sertraline or treatment responders and non-responders. Contrary to theories, changes in fragmentation may not be a crucial mechanism underlying PTSD therapeutic recovery.

  8. Trauma.

    Science.gov (United States)

    Huisman, Thierry A G M; Poretti, Andrea

    2016-01-01

    Traumatic brain and spine injury (TBI/TSI) is a leading cause of death and lifelong disability in children. The biomechanical properties of the child's brain, skull, and spine, the size of the child, the age-specific activity pattern, and variance in trauma mechanisms result in a wide range of age-specific traumas and patterns of brain and spine injuries. A detailed knowledge about the various types of primary and secondary pediatric head and spine injuries is essential to better identify and understand pediatric TBI/TSI, which enhances sensitivity and specificity of diagnosis, will guide therapy, and may give important information about the prognosis. The purposes of this chapter are to: (1) discuss the unique epidemiology, mechanisms, and characteristics of TBI/TSI in children; (2) review the anatomic and functional imaging techniques that can be used to study common and rare pediatric TBI/TSI and their complications; (3) comprehensively review frequent primary and secondary brain injuries; and (4) to give a short overview of two special types of pediatric TBI/TSI: birth-related and nonaccidental injuries. © 2016 Elsevier B.V. All rights reserved.

  9. TRAUMA

    African Journals Online (AJOL)

    purpose of this audit was to test this theory, using data from the Trauma Unit at Groote Schuur Hospital in Cape Town. The Trauma Unit at Groote Schuur Hospital ..... significant in predicting both crash incidence and severity.17. Study Limitations. This study gives insight into when busy times are expected and what types of ...

  10. TRAUMA

    African Journals Online (AJOL)

    as an indicator of EMS performance. Postoperative complications were graded according to Clavien-Dindo classification of surgical complications. Results: A total of 118 patients were admitted to the trauma surgery ward following abdominal trauma. The mechanism was penetrating 101 (85.6%) [stab wounds in 67 (56.8%) ...

  11. TRAUMA

    African Journals Online (AJOL)

    2017-11-04

    Nov 4, 2017 ... Introduction. Nonoperative management strategies have been suggested for the management of flail chest since the 1950s and most trauma surgeons still follow this approach today.1-4 However, follow-up studies on patients with rib fractures which have been managed nonoperatively have demostrated a ...

  12. TRAUMA

    African Journals Online (AJOL)

    key trauma procedures following successful completion of ATLS.10 However, it was noted that only 15% of all JDs had completed the ATLS course at the time of study.10 There is currently no literature focusing specifically on reasons for such low completion rate in our developing world setting. The aims of this study were to ...

  13. A multicenter study on dental trauma in permanent incisors among Special Olympics athletes in Europe and Eurasia.

    Science.gov (United States)

    Fernandez, Carla; Kaschke, Imke; Perlman, Steven; Koehler, Bjoern; Marks, Luc

    2015-11-01

    Special Olympics athletes, as part of the population with intellectual disabilities, are reported to be more vulnerable to dental injuries due to poor lip closure, slow response to environmental obstacles, oral pathologic reflexes, or dental features. The aim of this study was to assess the prevalence of dental trauma among Special Olympics athletes in countries of Europe and Eurasia. A retrospective longitudinal study was performed with data collected through standardized Special Smiles screening forms and procedures from consenting 15,941 athletes participating in the annual Special Olympics held in 49 countries from Europe and Eurasia between 2007 and 2012. The data was compiled in an Excel worksheet and transferred to an SPSS data file in order to be analyzed. A total of 2190 athletes presented dental injury (13.02%) with a std. deviation of 5.02%, and there were no significant differences (p = 0.136) in mean dental injury between age groups (one-way ANOVA test). The present data suggest that dental trauma is an actual problem among individuals with special needs. The distribution of prevalence among the different countries had a remarkable variability, but it is evident that a relatively high proportion of this population is in need of dental trauma preventive programs.

  14. Science Bubbles

    DEFF Research Database (Denmark)

    Hendricks, Vincent Fella; Pedersen, David Budtz

    2013-01-01

    Much like the trade and trait sof bubbles in financial markets,similar bubbles appear on the science market. When economic bubbles burst, the drop in prices causes the crash of unsustainable investments leading to an investor confidence crisis possibly followed by a financial panic. But when...... bubbles appear in science, truth and reliability are the first victims. This paper explores how fashions in research funding and research management may turn science into something like a bubble economy....

  15. Review of Current Literature and Research on Gas Supersaturation and Gas Bubble Trauma: Special Publication Number 1, 1986.

    Energy Technology Data Exchange (ETDEWEB)

    Colt, John; Bouck, Gerald R.; Fidler, Larry

    1986-12-01

    This report presents recently published information and on-going research on the various areas of gas supersaturation. Growing interest in the effects of chronic gas supersaturation on aquatic animals has been due primarily to heavy mortality of salmonid species under hatchery conditions. Extensive examination of affected animals has failed to consistently identify pathogenic organisms. Water quality sampling has shown that chronic levels of gas supersaturation are commonly present during a significant period of the year. Small marine fish larvae are significantly more sensitive to gas supersaturation than salmonids. Present water quality criteria for gas supersaturation are not adequate for the protection of either salmonids under chronic exposure or marine fish larvae, especially in aquaria or hatcheries. To increase communication between interested parties in the field of gas supersaturation research and control, addresses and telephone numbers of all people responding to the questionnaire are included. 102 refs.

  16. Bubble coalescence

    NARCIS (Netherlands)

    Orvalho, Sandra; Ruzicka, Marek C.; Olivieri, Giuseppe; Marzocchella, Antonio

    2015-01-01

    The goal of this study is to present new experimental data on the effect of the bubble approach velocity and liquid viscosity on pairwise bubble coalescence. Measurements were performed to investigate the dynamics of bubble coalescence under well-defined laboratory conditions. Air and pure

  17. TRAUMA AND ORTHOPEDIC MORBIDITY OF CHILDREN IN RUSSIA IN 2013. ORGANIZATION OF SPECIALIZED CARE FOR CHILDREN

    Directory of Open Access Journals (Sweden)

    Алексей Георгиевич Баиндурашвили

    2014-12-01

    Full Text Available The article is a summary of the materials presented at the X Jubilee Congress of Orthopedic and Trauma Surgeons of Russia on September 16, 2014, in Moscow by the director of the FSBI «Scientific and Research Institute for Children’s Orthopedics n. a. G. I. Turner», corr.-member of RAS Alexey Georgievich Baindurashvili. Statistical data on traumatism and morbidity of the musculoskeletal system of the child population, information on the organization of trauma and orthopedic care for children are based on data from the state statistical reports of the Russian Ministry of Health. These data may be useful to public health officials, and orthopedic and trauma surgeons in subjects of the Russian Federation.

  18. Bubble columns : Structures or stability?

    NARCIS (Netherlands)

    Harteveld, W.K.

    2005-01-01

    The aim of the thesis is to contribute to the understanding of the hydrodynamics of the gravity driven bubbly flow that can be found in bubble columns. Special attention is paid to the large scale structures that have a strong impact on several key parameters such as the degree of mixing, mass and

  19. A 2-year review of ocular trauma in Jimma University Specialized ...

    African Journals Online (AJOL)

    BACKGROUND: Ocular trauma is an important public health hazard with enormous human, social and economical consequences. Worldwide, there are about 1.6 million blind and 19 million with unilateral visual loss people from eye injuries. A study done at a teaching referral hospital in Addis Ababa revealed 15.8% of ...

  20. a 2-year review of ocular trauma i jimma u iversity specialized hospital

    African Journals Online (AJOL)

    user

    2008-06-30

    Jun 30, 2008 ... rehabilitation for the elderly. The problem in developing countries is compounded by general lack of access to preventive health care at all levels (10). In spite of these facts, ocular trauma seems to be one of the most unrecognized major health problems globally and nationally (2). Effective prevention must ...

  1. a 2-year review of ocular trauma i jimma u iversity specialized hospital

    African Journals Online (AJOL)

    user

    2008-06-30

    Jun 30, 2008 ... BACKGROU D: Ocular trauma is an important public health hazard with enormous human, social and ... visual morbidity. Worldwide, there are approximately 1.6 million people blinded from eye injuries, 2.3 million bilaterally visually impaired and 19 .... Rupture: Full thickness wound by blunt object by.

  2. Bubble Combustion

    Science.gov (United States)

    Corrigan, Jackie

    2004-01-01

    A method of energy production that is capable of low pollutant emissions is fundamental to one of the four pillars of NASA s Aeronautics Blueprint: Revolutionary Vehicles. Bubble combustion, a new engine technology currently being developed at Glenn Research Center promises to provide low emissions combustion in support of NASA s vision under the Emissions Element because it generates power, while minimizing the production of carbon dioxide (CO2) and nitrous oxides (NOx), both known to be Greenhouse gases. and allows the use of alternative fuels such as corn oil, low-grade fuels, and even used motor oil. Bubble combustion is analogous to the inverse of spray combustion: the difference between bubble and spray combustion is that spray combustion is spraying a liquid in to a gas to form droplets, whereas bubble combustion involves injecting a gas into a liquid to form gaseous bubbles. In bubble combustion, the process for the ignition of the bubbles takes place on a time scale of less than a nanosecond and begins with acoustic waves perturbing each bubble. This perturbation causes the local pressure to drop below the vapor pressure of the liquid thus producing cavitation in which the bubble diameter grows, and upon reversal of the oscillating pressure field, the bubble then collapses rapidly with the aid of the high surface tension forces acting on the wall of the bubble. The rapid and violent collapse causes the temperatures inside the bubbles to soar as a result of adiabatic heating. As the temperatures rise, the gaseous contents of the bubble ignite with the bubble itself serving as its own combustion chamber. After ignition, this is the time in the bubble s life cycle where power is generated, and CO2, and NOx among other species, are produced. However, the pollutants CO2 and NOx are absorbed into the surrounding liquid. The importance of bubble combustion is that it generates power using a simple and compact device. We conducted a parametric study using CAVCHEM

  3. Bubble, Bubble, Toil and Trouble.

    Science.gov (United States)

    Journal of Chemical Education, 2001

    2001-01-01

    Bubbles are a fun way to introduce the concepts of surface tension, intermolecular forces, and the use of surfactants. Presents two activities in which students add chemicals to liquid dishwashing detergent with water in order to create longer lasting bubbles. (ASK)

  4. Bubble diagnostics

    Science.gov (United States)

    Visuri, Steven R.; Mammini, Beth M.; Da Silva, Luiz B.; Celliers, Peter M.

    2003-01-01

    The present invention is intended as a means of diagnosing the presence of a gas bubble and incorporating the information into a feedback system for opto-acoustic thrombolysis. In opto-acoustic thrombolysis, pulsed laser radiation at ultrasonic frequencies is delivered intraluminally down an optical fiber and directed toward a thrombus or otherwise occluded vessel. Dissolution of the occlusion is therefore mediated through ultrasonic action of propagating pressure or shock waves. A vapor bubble in the fluid surrounding the occlusion may form as a result of laser irradiation. This vapor bubble may be used to directly disrupt the occlusion or as a means of producing a pressure wave. It is desirable to detect the formation and follow the lifetime of the vapor bubble. Knowledge of the bubble formation and lifetime yields critical information as to the maximum size of the bubble, density of the absorbed radiation, and properties of the absorbing material. This information can then be used in a feedback system to alter the irradiation conditions.

  5. Filter Bubble vs. Preference Bubble

    OpenAIRE

    Lindström, Hanna-Stiina; Soliman, Gabriela

    2016-01-01

    Tämän opinnäytetyön aiheena oli internetin personointi ja siitä aiheutuva filter bubble –ilmiö. Tarkoituksena oli tutkia kuluttajien suhtautumista ilmiöön, jota Suomessa ei vielä tunnisteta laajasti. Suhtautuminen haluttiin tuoda esiin vastakkainasettelun avulla. Filter bubble –näkökulma edusti tässä työssä ilmiön negatiivista suhtautumistapaa ja preference bubble –näkökulma positiivista. Opinnäytetyö oli tietopaketti yrityksille Filter bubble –ilmiön ominaisuuksista sekä sen käyttäytymisestä...

  6. Leverage bubble

    Science.gov (United States)

    Yan, Wanfeng; Woodard, Ryan; Sornette, Didier

    2012-01-01

    Leverage is strongly related to liquidity in a market and lack of liquidity is considered a cause and/or consequence of the recent financial crisis. A repurchase agreement is a financial instrument where a security is sold simultaneously with an agreement to buy it back at a later date. Repurchase agreement (repo) market size is a very important element in calculating the overall leverage in a financial market. Therefore, studying the behavior of repo market size can help to understand a process that can contribute to the birth of a financial crisis. We hypothesize that herding behavior among large investors led to massive over-leveraging through the use of repos, resulting in a bubble (built up over the previous years) and subsequent crash in this market in early 2008. We use the Johansen-Ledoit-Sornette (JLS) model of rational expectation bubbles and behavioral finance to study the dynamics of the repo market that led to the crash. The JLS model qualifies a bubble by the presence of characteristic patterns in the price dynamics, called log-periodic power law (LPPL) behavior. We show that there was significant LPPL behavior in the market before that crash and that the predicted range of times predicted by the model for the end of the bubble is consistent with the observations.

  7. Bubble drag reduction requires large bubbles

    CERN Document Server

    Verschoof, Ruben A; Sun, Chao; Lohse, Detlef

    2016-01-01

    In the maritime industry, the injection of air bubbles into the turbulent boundary layer under the ship hull is seen as one of the most promising techniques to reduce the overall fuel consumption. However, the exact mechanism behind bubble drag reduction is unknown. Here we show that bubble drag reduction in turbulent flow dramatically depends on the bubble size. By adding minute concentrations (6 ppm) of the surfactant Triton X-100 into otherwise completely unchanged strongly turbulent Taylor-Couette flow containing bubbles, we dramatically reduce the drag reduction from more than 40% to about 4%, corresponding to the trivial effect of the bubbles on the density and viscosity of the liquid. The reason for this striking behavior is that the addition of surfactants prevents bubble coalescence, leading to much smaller bubbles. Our result demonstrates that bubble deformability is crucial for bubble drag reduction in turbulent flow and opens the door for an optimization of the process.

  8. Trauma Team Activation: Not Just for Trauma Patients

    OpenAIRE

    Phoenix Vuong; Jason Sample; Mary Ellen Zimmermann; Pierre Saldinger

    2017-01-01

    Specialized trauma teams have been shown to improve outcomes in critically injured patients. At our institution, an the American College of Surgeons Committee on trauma level I Trauma center, the trauma team activation (TTA) criteria includes both physiologic and anatomic criteria, but any attending physician can activate the trauma team at their discretion outside criteria. As a result, the trauma team has been activated for noninjured patients meeting physiologic criteria secondary to nontr...

  9. [Trauma during pregnancy].

    Science.gov (United States)

    Siebenga, J; van der Schoot, J T; Keeman, J N

    1999-05-29

    Mortality due to trauma in pregnancy is not very common in the Netherlands. More often a pregnant woman presents herself for examination after trauma. Blunt trauma is more common in the third trimester. Minor trauma also needs good care, with special attention for solutio placentae. Maternal mortality after penetrating trauma is low because of the protection of vital organs by the uterus. With good treatment the mortality in pregnant trauma patients will not be higher than in nonpregnant patients. A rapid and effective resuscitation of the mother will give the foetus the best chance of survival.

  10. Bubbles and foams in microfluidics.

    Science.gov (United States)

    Huerre, Axel; Miralles, Vincent; Jullien, Marie-Caroline

    2014-09-28

    Microfluidics offers great tools to produce highly-controlled dispersions of gas into liquid, from isolated bubbles to organized microfoams. Potential technological applications are manifold, from novel materials to scaffolds for tissue engineering or enhanced oil recovery. More fundamentally, microfluidics makes it possible to investigate the physics of complex systems such as foams at scales where the capillary forces become dominant, in model experiments involving few well-controlled parameters. In this context, this review does not have the ambition to detail in a comprehensive manner all the techniques and applications involving bubbles and foams in microfluidics. Rather, it focuses on particular consequences of working at the microscale, under confinement, and hopes to provide insight into the physics of such systems. The first part of this work focuses on bubbles, and more precisely on (i) bubble generation, where the confinement can suppress capillary instabilities while inertial effects may play a role, and (ii) bubble dynamics, paying special attention to the lubrication film between bubble and wall and the influence of confinement. The second part addresses the formation and dynamics of microfoams, emphasizing structural differences from macroscopic foams and the influence of the confinement.

  11. Bubble bath soap poisoning

    Science.gov (United States)

    ... medlineplus.gov/ency/article/002762.htm Bubble bath soap poisoning To use the sharing features on this page, please enable JavaScript. Bubble bath soap poisoning occurs when someone swallows bubble bath soap. ...

  12. Emergency Department Management of Trauma

    DEFF Research Database (Denmark)

    MacKenzie, Colin; Lippert, Freddy

    1999-01-01

    Initial assessment and management of severely injured patients may occur in a specialized area of an emergency department or in a specialized area of a trauma center. The time from injury until definitive management is of essence for survival of life-threatening trauma. The initial care delivered...... injured patients after these patients reach a hospital emergency department or a trauma center....

  13. Fama on bubbles

    DEFF Research Database (Denmark)

    Engsted, Tom

    Eugene Fama has repeatedly expressed his discontent with the notion of an irrational bubble. However, he has never publicly expressed his opinion on rational bubbles. This is peculiar since such bubbles build naturally from the rational efficient markets paradigm that Fama strongly adheres to. On......, there is evidence of an explosive component in stock market valuation ratios, consistent with a rational bubble........ On empirical grounds Fama rejects bubbles by referring to the lack of reliable evidence that price declines are predictable. However, this argument cannot be used to rule out rational bubbles because such bubbles do not necessarily imply return predictability. On data samples that include the 1990s...

  14. Measuring bubbles in a bubbly wake flow

    Science.gov (United States)

    Lee, Seung-Jae; Kawakami, Ellison; Arndt, Roger E. A.

    2012-11-01

    This paper presents measurements of the velocity and size distribution of bubbles in a bubbly wake. This was carried out by utilizing particle shadow velocimetry (PSV). This technique is a non-scattering approach that relies on direct in-line volume illumination by a pulsed source such as a light-emitting diode (LED). A narrow depth-of-field (DoF) is required for imaging a 2-dimensional plane within a flow volume. Shadows of the bubbles were collected by a high-speed camera. Once a reference image, taken when no bubbles were present in the flow, was subtracted from the images, the image was segmented using an edge detection technique. The Canny algorithm was determined to be best suited for this application. A curvature profile method was employed to distinguish individual bubbles within a cluster of highly overlapping bubbles. The utilized algorithm was made to detect partly overlapping bubbles and reconstruct the missing parts. The movement of recognized individual bubbles was tracked on a two dimensional plane within a flow volume. In order to obtain quantitative results, the wake of a ventilated hydrofoil was investigated by applying the shadowgraphy technique and the described bubble detection algorithm. These experiments were carried out in the high speed cavitation tunnel at Saint Anthony Falls Laboratory (SAFL) of the University of Minnesota. This research is jointly sponsored by the Office of Naval Re- search, Dr. Ron Joslin, program manager, and the Department of Energy, Golden Field Office.

  15. Fama on Bubbles

    DEFF Research Database (Denmark)

    Engsted, Tom

    2016-01-01

    . However, this argument cannot be used to rule out rational bubbles because such bubbles do not necessarily imply return predictability, and return predictability of the kind documented by Fama does not rule out rational bubbles. On data samples that include the 1990s, there is evidence of an explosive......While Eugene Fama has repeatedly expressed his discontent with the notion of an “irrational bubble,” he has never publicly expressed his opinion on “rational bubbles.” On empirical grounds Fama rejects bubbles by referring to the lack of reliable evidence that price declines are predictable...

  16. Soap Bubbles and Crystals

    Indian Academy of Sciences (India)

    volume work summarizing his decades of research into soap bubbles and related phe- nomena due to surface tension. He gave the rules governing the geometry of bubbles, without any proof. It is a remarkable achievement as these experiments.

  17. Soap Bubbles and Logic.

    Science.gov (United States)

    Levine, Shellie-helane; And Others

    1986-01-01

    Introduces questions and activities involving soap bubbles which provide students with experiences in prediction and logic. Examines commonly held false conceptions related to the shapes that bubbles take and provides correct explanations for the phenomenon. (ML)

  18. Economic Growth with Bubbles

    OpenAIRE

    Alberto Martin

    2010-01-01

    This paper presents a stylized model of economic growth with bubbles. This model views asset price bubbles as a market-generated device to moderate the effects of frictions in financial markets, improving the allocation of investments and raising the capital stock and welfare. It shows that, contrary to conventional wisdom, bubbles can arise even if all investments in the economy are dynamically efficient.

  19. Soap Films and Bubbles.

    Science.gov (United States)

    Rice, Karen

    1986-01-01

    Develops and explains a format for a workshop which focuses on soap films and bubbles. The plan consists of: a discussion to uncover what children know about bubbles; explanations of the demonstration equipment; the presentation itself; the assembly of the workshop kit; and time to play with the bubbles. (ML)

  20. Trauma team activation: Not just for trauma patients

    Directory of Open Access Journals (Sweden)

    Phoenix Vuong

    2017-01-01

    Full Text Available Specialized trauma teams have been shown to improve outcomes in critically injured patients. At our institution, an the American College of Surgeons Committee on trauma level I Trauma center, the trauma team activation (TTA criteria includes both physiologic and anatomic criteria, but any attending physician can activate the trauma team at their discretion outside criteria. As a result, the trauma team has been activated for noninjured patients meeting physiologic criteria secondary to nontraumatic hemorrhage. We present two cases in which the trauma team was activated for noninjured patients in hemorrhagic shock. The utilization of the TTA protocol and subsequent management by the trauma team are reviewed as we believe these were critical factors in the successful recovery of both patients. Beyond the primary improved survival outcomes of severely injured patients, trauma center designation has a “halo effect” that encompasses patients with nontraumatic hemorrhage.

  1. Cavitation bubble dynamics.

    Science.gov (United States)

    Lauterborn, W; Ohl, C D

    1997-04-01

    The dynamics of cavitation bubbles on water is investigated for bubbles produced optically and acoustically. Single bubble dynamics is studied with laser produced bubbles and high speed photography with framing rates up to 20.8 million frames per second. Examples for jet formation and shock wave emission are given. Acoustic cavitation is produced in water in the interior of piezoelectric cylinders of different sizes (up to 12 cm inner diameter). The filementary structure composed of bubbles is investigated and their light emission (sonoluminescence) studied for various driving strengths.

  2. Effect of bubble deformability on the vertical channel bubbly flow

    OpenAIRE

    Dabiri, Sadegh; Lu, Jiacai; Tryggvason, Gretar

    2012-01-01

    This article describes the fluid dynamics video: "Effect of bubble deformability on the vertical channel bubbly flow". The effect of bubble deformability on the flow rate of bubbly upflow in a turbulent vertical channel is examined using direct numerical simulations. A series of simulations with bubbles of decreasing deformability reveals a sharp transition from a flow with deformable bubbles uniformly distributed in the middle of the channel to a flow with nearly spherical bubbles with a wal...

  3. Conformal gravity and "gravitational bubbles"

    CERN Document Server

    Berezin, V A; Eroshenko, Yu N

    2015-01-01

    We describe the general structure of the spherically symmetric solutions in the Weyl conformal gravity. The corresponding Bach equations are derived for the special type of metrics, which can be considered as the representative of the general class. The complete set of the pure vacuum solutions, consisting of two classes, is found. The first one contains the solutions with constant two-dimensional curvature scalar, and the representatives are the famous Robertson--Walker metrics. We called one of them the "gravitational bubbles", which is compact and with zero Weyl tensor. These "gravitational bubbles" are the pure vacuum curved space-times (without any material sources, including the cosmological constant), which are absolutely impossible in General Relativity. This phenomenon makes it easier to create the universe from "nothing". The second class consists of the solutions with varying curvature scalar. We found its representative as the one-parameter family, which can be conformally covered by the thee-para...

  4. A practice research study concerning homeless service user involvement with a programme of social support work delivered in a specialized psychological trauma service.

    Science.gov (United States)

    Archard, P J; Murphy, D

    2015-08-01

    Homeless persons are known to be highly vulnerable to psychological trauma, in events triggering periods of homelessness and the considerable social isolation and adversity suffered when homeless. This study provides an account of how mental health support work is experienced by homeless service users when it is informed by a person-centred, non-directive approach and implemented by trainee health and social care professionals under the auspices of a specialized psychological trauma service. The study draws upon material gathered from interviews with service users domiciled in supported housing for homeless persons and support workers who practiced on the programme. The service users who participated in the study valued support work that combined practical and relational elements, but would have preferred a longer-term involvement. They also spoke of feelings of disconnection and estrangement from others including their peers in supported housing. The support worker participants valued the flexibility they had when working on the programme to tailor their intervention to service users' individual needs. Practice implications of the study are discussed. These include the need to minimize barriers to accessing support, facilitate informal time between professionals and homeless service users, and manage intervention endings sensitively when temporary staffing arrangements are in place. Homeless people are a population known to be highly vulnerable to trauma, in triggering events to becoming homeless and the considerable social isolation, discrimination, and adversity suffered when homeless. Currently, there is a paucity of research into mental health service delivery to homeless persons and the influence it imparts in individual lives. This article presents a qualitative 'practice research' study into a pilot programme of social support work delivered in a specialized psychological trauma service to homeless service users. The programme was grounded in a non

  5. Bubbling and bistability in two parameter discrete systems

    Indian Academy of Sciences (India)

    We present a graphical analysis of the mechanisms underlying the occurrences of bubbling sequences and bistability regions in the bifurcation scenario of a special class of one dimensional two parameter maps. The main result of the analysis is that whether it is bubbling or bistability is decided by the sign of the third ...

  6. Planar Soap Bubbles

    OpenAIRE

    Vaughn, Rick

    1998-01-01

    The generalized soap bubble problem seeks the least perimeter way to enclose and separate n given volumes in R^m. We study the possible configurations for perimeter minimizing bubble complexes enclosing more than two regions. We prove that perimeter minimizing planar bubble complexes with equal pressure regions and without empty chambers must have connected regions. As a consequence, we show that the least perimeter planar graph that...

  7. Magnetic bubble materials.

    Science.gov (United States)

    Giess, E A

    1980-05-23

    Physicists, materials scientists, and engineers combined to bring solid-state bubble devices into the computer memory and recording marketplace. Devices with smaller bubbles are being developed for increased data capacity and lower cost. Epitaxial garnet films made by isothermal dipping in molten solutions helped put the technology in place and will probably satisfy the material needs of future devices with bubbles scaled down from 2 to 0.5 micrometer in size.

  8. Sonochemistry and bubble dynamics.

    Science.gov (United States)

    Mettin, Robert; Cairós, Carlos; Troia, Adriano

    2015-07-01

    The details of bubble behaviour in chemically active cavitation are still not sufficiently well understood. Here we report on experimental high-speed observations of acoustically driven single-bubble and few-bubble systems with the aim of clarification of the connection of their dynamics with chemical activity. Our experiment realises the sonochemical isomerization reaction of maleic acid to fumaric acid, mediated by bromine radicals, in a bubble trap set-up. The main result is that the reaction product can only be observed in a parameter regime where a small bubble cluster occurs, while a single trapped bubble stays passive. Evaluations of individual bubble dynamics for both cases are given in form of radius-time data and numerical fits to a bubble model. A conclusion is that a sufficiently strong collapse has to be accompanied by non-spherical bubble dynamics for the reaction to occur, and that the reason appears to be an efficient mixing of liquid and gas phase. This finding corroborates previous observations and literature reports on high liquid phase sonochemical activity under distinct parameter conditions than strong sonoluminescence emissions. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Bubble and drop interfaces

    CERN Document Server

    Miller

    2011-01-01

    The book aims at describing the most important experimental methods for characterizing liquid interfaces, such as drop profile analysis, bubble pressure and drop volume tensiometry, capillary pressure technique, and oscillating drops and bubbles. Besides the details of experimental set ups, also the underlying theoretical basis is presented in detail. In addition, a number of applications based on drops and bubbles is discussed, such as rising bubbles and the very complex process of flotation. Also wetting, characterized by the dynamics of advancing contact angles is discussed critically. Spec

  10. A bubble detection system for propellant filling pipeline.

    Science.gov (United States)

    Wen, Wen; Zong, Guanghua; Bi, Shusheng

    2014-06-01

    This paper proposes a bubble detection system based on the ultrasound transmission method, mainly for probing high-speed bubbles in the satellite propellant filling pipeline. First, three common ultrasonic detection methods are compared and the ultrasound transmission method is used in this paper. Then, the ultrasound beam in a vertical pipe is investigated, suggesting that the width of the beam used for detection is usually smaller than the internal diameter of the pipe, which means that when bubbles move close to the pipe wall, they may escape from being detected. A special device is designed to solve this problem. It can generate the spiral flow to force all the bubbles to ascend along the central line of the pipe. In the end, experiments are implemented to evaluate the performance of this system. Bubbles of five different sizes are generated and detected. Experiment results show that the sizes and quantity of bubbles can be estimated by this system. Also, the bubbles of different radii can be distinguished from each other. The numerical relationship between the ultrasound attenuation and the bubble radius is acquired and it can be utilized for estimating the unknown bubble size and measuring the total bubble volume.

  11. The effect of counting principal and secondary injuries on national estimates of motor vehicle-related trauma: a NEISS-AIP special study.

    Science.gov (United States)

    Halpin, J; Greenspan, A I; Haileyesus, T; Annest, J L

    2009-10-01

    To demonstrate the effect of including both principal and secondary injuries in the calculation of national estimates of non-fatal motor vehicle-related injury, using the National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP). The setting was a stratified sample of 15 US hospital emergency departments selected among 50 NEISS-AIP hospitals which agreed to participate in the study. Non-fatal injury data from a special study of the 2004 NEISS-AIP were analysed which allowed up to five injuries to be coded per case. National estimates of number and rate of injuries for 2004 were calculated, first using principal injuries alone, then by including principal and secondary injuries. An estimated 4,833,626 principal and secondary injuries were sustained by the estimated 2,893,782 motor vehicle occupants involved in a crash and treated in US hospital emergency departments (EDs) in 2004. This represents a 67% increase in the total number of injuries compared with an estimate of principal injury alone. Incidence of contusions/abrasions and lower trunk injuries rose most steeply among broad injury types, and whiplash injury rose 18% in number and rate. A significantly lower percentage of cases with a single listed injury were hospitalised (5%) compared with those who sustained multiple injuries (8%). Based on an analysis of NEISS-AIP special study data, the inclusion of both principal and secondary injuries in national estimates of motor vehicle-related occupant injury would provide a more comprehensive report of non-fatal injuries treated in US hospital EDs. Other countries with ED-based surveillance systems could consider reporting multiple injuries when assessing injury count associated with motor vehicle trauma requiring ED care.

  12. Bubbles, Banks, and Financial Stability

    OpenAIRE

    Kosuke Aoki; Kalin Nikolov

    2011-01-01

    This paper asks two main questions: (1) What makes some asset price bubbles more costly for the real economy than others? and (2) When do costly bubbles occur? We construct a model of rational bubbles under credit frictions and show that when bubbles held by banks burst this is followed by a costly financial crisis. In contrast, bubbles held by ordinary savers have relatively muted effects. Banks tend to invest in bubbles when financial liberalisation decreases their profitability.

  13. Single bubble sonoluminescence

    NARCIS (Netherlands)

    Brenner, Michael P.; Hilgenfeldt, Sascha; Lohse, Detlef

    2002-01-01

    Single-bubble sonoluminescence occurs when an acoustically trapped and periodically driven gas bubble collapses so strongly that the energy focusing at collapse leads to light emission. Detailed experiments have demonstrated the unique properties of this system: the spectrum of the emitted light

  14. Bubbles in graphene

    DEFF Research Database (Denmark)

    Settnes, Mikkel; Power, Stephen; Lin, Jun

    2015-01-01

    Strain-induced deformations in graphene are predicted to give rise to large pseudomagnetic fields. We examine theoretically the case of gas-inflated bubbles to determine whether signatures of such fields are present in the local density of states. Sharp-edged bubbles are found to induce Friedel...

  15. Understanding the bubbles

    DEFF Research Database (Denmark)

    Turcan, Romeo V.

    that are identified to exist between the Internet and housing market bubbles: uncertainty and sentiments. The iteration between uncertainty and sentiments leads to the emergence of the third commonality: residue. The residue is the difference between the actors’ overall sentiment about exaggerated future prospects......Understanding how and why bubbles occur as well as whether these could be anticipated, managed, or even prevented is equally important as to know how to recover from them. To address these questions, a model of bubble emergence is put forward. The model builds on two fundamental commonalities...... of a new venture and intended outcomes of that new venture; the higher the residue, the higher the likelihood of the bubble emergence; as residue increases, the likelihood of bubble burst increases. One question that arises is whether one can manage the hype, hence the residue. In this, it is maintained...

  16. Bubble motion measurements during foam drainage and coarsening.

    Science.gov (United States)

    Maurdev, G; Saint-Jalmes, A; Langevin, D

    2006-08-15

    We have studied bubble motion within a column of foam allowed to undergo free drainage. We have measured bubble motion upward with time and as a function of their initial positions. Depending on the gas used, which sets the coarsening and drainage rates, different bubble upward motion types have been identified (constant speed, acceleration or deceleration) and explained in relation with liquid downward flows. The proofs of the consistency between bubble upward motion and liquid downward flow are obtained both by comparing the bubble motion curves to the liquid drainage ones, and by comparing the time variations of the liquid fraction extracted from bubble motion to direct liquid fraction measurements by electrical conductimetry. The agreement between bubble position tracking and electrical conductivity shows in particular that it is possible to determine the drainage regime from such simple bubble motion measurements. This work also allowed us to demonstrate a special case of foam coarsening and expansion, occurring when the foam gas is less soluble than the outside one, caused by diffusion of this external gas into the foam. All these results allow us to build a picture of drainage and coarsening seen from the bubble point of view.

  17. Bubble impacts with microcantilevers.

    Science.gov (United States)

    Stegmeir, Matthew; Longmire, Ellen; Ali, Mubassar; Mantell, Susan

    2006-11-01

    In the current study, we investigate bubbles in laminar channel flows impacting microcantilever obstacles. Static and resonating cantilevers instrumented with integrated strain gages are mounted perpendicular to the mean flow in a vertically-oriented channel with thickness 2mm, span 10mm, and length 585 mm. Steady, fully-developed upward flows with channel Reynolds numbers based on mean fluid velocity and hydraulic diameter of 0-2500 are considered. Bubbles of diameter 200-1000μm are introduced upstream of the test section, and impacts are observed using a microscope equipped with a high frame rate camera. Observations are made along the length of cantilevers backlit with white light. Strain gage signals are monitored and correlated to impact events. The effect of obstacles on bubble motion and deformation as well as the effect of bubble impacts on the cantilever will be discussed. The flow studies are part of a larger research program examining reliability and performance of vibrating microbeams.

  18. Chemistry in Soap Bubbles.

    Science.gov (United States)

    Lee, Albert W. M.; Wong, A.; Lee, H. W.; Lee, H. Y.; Zhou, Ning-Huai

    2002-01-01

    Describes a laboratory experiment in which common chemical gases are trapped inside soap bubbles. Examines the physical and chemical properties of the gases such as relative density and combustion. (Author/MM)

  19. Bubble dynamics in DNA

    Energy Technology Data Exchange (ETDEWEB)

    Hanke, Andreas [Institut fuer Theoretische Physik, Universitaet Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart (Germany); Metzler, Ralf [NORDITA-Nordic Institute for Theoretical Physics, Blegdamsvej 17, DK-2100 Copenhagen O (Denmark)

    2003-09-12

    The formation of local denaturation zones (bubbles) in double-stranded DNA is an important example of conformational changes of biological macromolecules. We study the dynamics of bubble formation in terms of a Fokker-Planck equation for the probability density to find a bubble of size n base pairs at time t, on the basis of the free energy in the Poland-Scheraga model. Characteristic bubble closing and opening times can be determined from the corresponding first passage time problem, and are sensitive to the specific parameters entering the model. A multistate unzipping model with constant rates recently applied to DNA breathing dynamics (Altan-Bonnet et al 2003 Phys. Rev. Lett. 90 138101) emerges as a limiting case. (letter to the editor)

  20. Simulation of special bubble detectors for PICASSO.

    Science.gov (United States)

    Azuelos, G; Barnabé-Heider, M; Behnke, E; Clark, K; Di Marco, M; Doane, P; Feighery, W; Genest, M-H; Gornea, R; Guénette, R; Kanagalingam, S; Krauss, C; Leroy, C; Lessard, L; Levine, I; Martin, J P; Noble, A J; Noulty, R; Shore, S N; Wichoski, U; Zacek, V

    2006-01-01

    The PICASSO project is a cold dark matter (CDM) search experiment relying on the superheated droplet technique. The detectors use superheated freon liquid droplets (active material) dispersed and trapped in a polymerised gel. This detection technique is based on the phase transition of superheated droplets at about room temperature and ambient pressure. The phase transition is induced by nuclear recoils when an atomic nucleus in the droplets interacts with incoming subatomic particles. This includes CDM particles candidate as the neutralino (a yet-to-discover particle predicted in extensions of the standard model of particle physics). Simulations performed to understand the detector response to neutrons and alpha particles are presented along with corresponding data obtained at the Montreal Laboratory.

  1. Systemic trauma.

    Science.gov (United States)

    Goldsmith, Rachel E; Martin, Christina Gamache; Smith, Carly Parnitzke

    2014-01-01

    Substantial theoretical, empirical, and clinical work examines trauma as it relates to individual victims and perpetrators. As trauma professionals, it is necessary to acknowledge facets of institutions, cultures, and communities that contribute to trauma and subsequent outcomes. Systemic trauma-contextual features of environments and institutions that give rise to trauma, maintain it, and impact posttraumatic responses-provides a framework for considering the full range of traumatic phenomena. The current issue of the Journal of Trauma & Dissociation is composed of articles that incorporate systemic approaches to trauma. This perspective extends conceptualizations of trauma to consider the influence of environments such as schools and universities, churches and other religious institutions, the military, workplace settings, hospitals, jails, and prisons; agencies and systems such as police, foster care, immigration, federal assistance, disaster management, and the media; conflicts involving war, torture, terrorism, and refugees; dynamics of racism, sexism, discrimination, bullying, and homophobia; and issues pertaining to conceptualizations, measurement, methodology, teaching, and intervention. Although it may be challenging to expand psychological and psychiatric paradigms of trauma, a systemic trauma perspective is necessary on both scientific and ethical grounds. Furthermore, a systemic trauma perspective reflects current approaches in the fields of global health, nursing, social work, and human rights. Empirical investigations and intervention science informed by this paradigm have the potential to advance scientific inquiry, lower the incidence of a broader range of traumatic experiences, and help to alleviate personal and societal suffering.

  2. Colliding with a crunching bubble

    Energy Technology Data Exchange (ETDEWEB)

    Freivogel, Ben; Freivogel, Ben; Horowitz, Gary T.; Shenker, Stephen

    2007-03-26

    In the context of eternal inflation we discuss the fate of Lambda = 0 bubbles when they collide with Lambda< 0 crunching bubbles. When the Lambda = 0 bubble is supersymmetric, it is not completely destroyed by collisions. If the domain wall separating the bubbles has higher tension than the BPS bound, it is expelled from the Lambda = 0 bubble and does not alter its long time behavior. If the domain wall saturates the BPS bound, then it stays inside the Lambda = 0 bubble and removes a finite fraction of future infinity. In this case, the crunch singularity is hidden behind the horizon of a stable hyperbolic black hole.

  3. A Bubble Bursts

    Science.gov (United States)

    2005-01-01

    RCW 79 is seen in the southern Milky Way, 17,200 light-years from Earth in the constellation Centaurus. The bubble is 70-light years in diameter, and probably took about one million years to form from the radiation and winds of hot young stars. The balloon of gas and dust is an example of stimulated star formation. Such stars are born when the hot bubble expands into the interstellar gas and dust around it. RCW 79 has spawned at least two groups of new stars along the edge of the large bubble. Some are visible inside the small bubble in the lower left corner. Another group of baby stars appears near the opening at the top. NASA's Spitzer Space Telescope easily detects infrared light from the dust particles in RCW 79. The young stars within RCW 79 radiate ultraviolet light that excites molecules of dust within the bubble. This causes the dust grains to emit infrared light that is detected by Spitzer and seen here as the extended red features.

  4. Explosive Bubble Modelling by Noncausal Process

    OpenAIRE

    Christian Gouriéroux; Jean-Michel Zakoian

    2013-01-01

    The linear mixed causal and noncausal autoregressive processes provide often a better fit to economic and financial time series than the standard causal linear autoregressive processes. By considering the example of the noncausal Cauchy autoregressive process, we show that it might be explained by the special associated nonlinear causal dynamics. Indeed, this causal dynamics can include unit root, bubble phenomena, or asymmetric cycles often observed on financial markets. The noncausal Cauchy...

  5. Bubble nuclei; Noyaux Bulles

    Energy Technology Data Exchange (ETDEWEB)

    Legoll, F. [Service de Physique Theorique, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1998-07-22

    For nuclei with very high electrical charge, the Coulomb field is expected to drive the protons away from the centre to the surface of the nucleus. Such a nucleus would be no more compact but look like a bubble. The goal of this work is to confirm this idea. We are interested in only the ground state of spherical nuclei. We use the Skyrme potential with the Sly4 parametrization to calculate the mean-field Hamiltonian. Paring correlations are described by a surface-active delta paring interaction. In its ground state the nucleus {sup A=900} X{sub Z=274} is shown to be a bubble. Another stable state is found with a little higher energy: it is also a bubble. (author) 11 refs., 18 figs., 33 tabs.

  6. Multivariate bubbles and antibubbles

    Science.gov (United States)

    Fry, John

    2014-08-01

    In this paper we develop models for multivariate financial bubbles and antibubbles based on statistical physics. In particular, we extend a rich set of univariate models to higher dimensions. Changes in market regime can be explicitly shown to represent a phase transition from random to deterministic behaviour in prices. Moreover, our multivariate models are able to capture some of the contagious effects that occur during such episodes. We are able to show that declining lending quality helped fuel a bubble in the US stock market prior to 2008. Further, our approach offers interesting insights into the spatial development of UK house prices.

  7. Condensation of vapor bubble in subcooled pool

    Science.gov (United States)

    Horiuchi, K.; Koiwa, Y.; Kaneko, T.; Ueno, I.

    2017-02-01

    We focus on condensation process of vapor bubble exposed to a pooled liquid of subcooled conditions. Two different geometries are employed in the present research; one is the evaporation on the heated surface, that is, subcooled pool boiling, and the other the injection of vapor into the subcooled pool. The test fluid is water, and all series of the experiments are conducted under the atmospheric pressure condition. The degree of subcooling is ranged from 10 to 40 K. Through the boiling experiment, unique phenomenon known as microbubble emission boiling (MEB) is introduced; this phenomenon realizes heat flux about 10 times higher than the critical heat flux. Condensation of the vapor bubble is the key phenomenon to supply ambient cold liquid to the heated surface. In order to understand the condensing process in the MEB, we prepare vapor in the vapor generator instead of the evaporation on the heated surface, and inject the vapor to expose the vapor bubble to the subcooled liquid. Special attention is paid to the dynamics of the vapor bubble detected by the high-speed video camera, and on the enhancement of the heat transfer due to the variation of interface area driven by the condensation.

  8. The Liberal Arts Bubble

    Science.gov (United States)

    Agresto, John

    2011-01-01

    The author expresses his doubt that the general higher education bubble will burst anytime soon. Although tuition, student housing, and book costs have all increased substantially, he believes it is still likely that the federal government will continue to pour billions into higher education, largely because Americans have been persuaded that it…

  9. BEBC bubble chamber

    CERN Multimedia

    CERN PhotoLab

    1972-01-01

    Looking up into the interior of BEBC bubble chamber from the expansion cylinder. At the top of the chamber two fish-eye lenses are installed and three other fish-eye ports are blanked off. In the centre is a heat exchanger.

  10. Scanning bubble chamber pictures

    CERN Multimedia

    1974-01-01

    These were taken at the 2 m hydrogen bubble chamber. The photo shows an early Shiva system where the pre-measurements needed to qualify the event were done manually (cf photo 7408136X). The scanning tables were located in bld. 12. Gilberte Saulmier sits on foreground, Inge Arents at centre.

  11. Heavy liquid bubble chamber

    CERN Multimedia

    CERN PhotoLab

    1965-01-01

    The CERN Heavy liquid bubble chamber being installed in the north experimental hall at the PS. On the left, the 1180 litre body; in the centre the magnet, which can produce a field of 26 800 gauss; on the right the expansion mechanism.

  12. Bubble properties of heterogeneous bubbly flow in a square bubble column

    NARCIS (Netherlands)

    Bai, W.; Deen, N.G.; Kuipers, J.A.M.

    2010-01-01

    The present work focuses on the measurements of bubble properties in heterogeneous bubbly flows in a square bubble column. A four-point optical fibre probe was used for this purpose. The accuracy and intrusive effect of the optical probe was investigated first. The results show that the optical

  13. Characteristics of bubble plumes, bubble-plume bubbles and waves from wind-steepened wave breaking

    NARCIS (Netherlands)

    Leifer, I.; Caulliez, G.; Leeuw, G. de

    2007-01-01

    Observations of breaking waves, associated bubble plumes and bubble-plume size distributions were used to explore the coupled evolution of wave-breaking, wave properties and bubble-plume characteristics. Experiments were made in a large, freshwater, wind-wave channel with mechanical wind-steepened

  14. Bubbling controlled by needle movement

    Energy Technology Data Exchange (ETDEWEB)

    Vejrazka, Jiri; Fujasova, Maria; Stanovsky, Petr; Ruzicka, Marek C; Drahos, JirI [Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, Rozvojova 135, 165 02 Prague (Czech Republic)], E-mail: vejrazka@icpf.cas.cz

    2008-07-30

    A device for 'on-demand' production of bubbles is presented. The device is based on a movable needle, through which air is injected. Bubbling is controlled by a rapid needle movement, which induces the bubble detachment. Conditions for proper function of the device include the restriction on the flow rate through the needle, sufficient needle pressure drop and adequate needle acceleration. Functionality of the device is demonstrated. Bubbling from a stationary needle is also discussed and a scaling for bubble size is proposed for the case of short needles, to which a constant flow rate is imposed through tubes of a finite volume.

  15. Bubble Dynamics and Shock Waves

    CERN Document Server

    2013-01-01

    This volume of the Shock Wave Science and Technology Reference Library is concerned with the interplay between bubble dynamics and shock waves. It is divided into four parts containing twelve chapters written by eminent scientists. Topics discussed include shock wave emission by laser generated bubbles (W Lauterborn, A Vogel), pulsating bubbles near boundaries (DM Leppinen, QX Wang, JR Blake), interaction of shock waves with bubble clouds (CD Ohl, SW Ohl), shock propagation in polydispersed bubbly liquids by model equations (K Ando, T Colonius, CE Brennen. T Yano, T Kanagawa,  M Watanabe, S Fujikawa) and by DNS (G Tryggvason, S Dabiri), shocks in cavitating flows (NA Adams, SJ Schmidt, CF Delale, GH Schnerr, S Pasinlioglu) together with applications involving encapsulated bubble dynamics in imaging (AA Doinikov, A Novell, JM Escoffre, A Bouakaz),  shock wave lithotripsy (P Zhong), sterilization of ships’ ballast water (A Abe, H Mimura) and bubbly flow model of volcano eruptions ((VK Kedrinskii, K Takayama...

  16. Ring Bubbles of Dolphins

    Science.gov (United States)

    Shariff, Karim; Marten, Ken; Psarakos, Suchi; White, Don J.; Merriam, Marshal (Technical Monitor)

    1996-01-01

    The article discusses how dolphins create and play with three types of air-filled vortices. The underlying physics is discussed. Photographs and sketches illustrating the dolphin's actions and physics are presented. The dolphins engage in this behavior on their own initiative without food reward. These behaviors are done repeatedly and with singleminded effort. The first type is the ejection of bubbles which, after some practice on the part of the dolphin, turn into toroidal vortex ring bubbles by the mechanism of baroclinic torque. These bubbles grow in radius and become thinner as they rise vertically to the surface. One dolphin would blow two in succession and guide them to fuse into one. Physicists call this a vortex reconnection. In the second type, the dolphins first create an invisible vortex ring in the water by swimming on their side and waving their tail fin (also called flukes) vigorously. This vortex ring travels horizontally in the water. The dolphin then turns around, finds the vortex and injects a stream of air into it from its blowhole. The air "fills-out" the core of the vortex ring. Often, the dolphin would knock-off a smaller ring bubble from the larger ring (this also involves vortex reconnection) and steer the smaller ring around the tank. One other dolphin employed a few other techniques for planting air into the fluke vortex. One technique included standing vertically in the water with tail-up, head-down and tail piercing the free surface. As the fluke is waved to create the vortex ring, air is entrained from above the surface. Another technique was gulping air in the mouth, diving down, releasing air bubbles from the mouth and curling them into a ring when they rose to the level of the fluke. In the third type, demonstrated by only one dolphin, the longitudinal vortex created by the dorsal fin on the back is used to produce 10-15 foot long helical bubbles. In one technique she swims in a curved path. This creates a dorsal fin vortex since

  17. Explosive bubbles in house prices? Evidence from the OECD countries

    DEFF Research Database (Denmark)

    Engsted, Tom; Hviid, Simon Juul; Pedersen, Thomas Quistgaard

    We conduct an econometric analysis of bubbles in housing markets in the OECD area, using quarterly OECD data for 18 countries from 1970 to 2013. We pay special attention to the explosive nature of bubbles and use econometric methods that explicitly allow for explosiveness. First, we apply...... the univariate right-tailed unit root test procedure of Phillips et al. (2012) on the individual countries price-rent ratio. Next, we use Engsted and Nielsen's (2012) co-explosive VAR framework to test for bubbles. We find evidence of explosiveness in many housing markets, thus supporting the bubble hypothesis....... However, we also find interesting differences in the conclusions across the two test procedures. We attribute these differences to how the two test procedures control for cointegration between house prices and rent....

  18. Collision of counterpropagating laser-excited wake bubbles

    Science.gov (United States)

    Deng, Z. G.; Yang, L.; Zhou, C. T.; Yu, M. Y.; Ying, H. P.; Wang, X. G.

    2014-06-01

    The collision of wake bubbles behind two counterpropagating laser pulses in rarefied plasma is investigated using particle-in-cell simulation. Special attention is paid to the highly nonlinear dynamics of the electrons in the interaction region. It is found that, as the two bubbles approach each other and collide, the electrons in the interaction region first oscillate in a periodic fashion, forming a quasistationary dense electron density ripple with fairly regular spatial structure. At longer times, the electron motion becomes chaotic, and the density grating is gradually smeared. The electrons escape in the transverse direction, and eventually the two bubbles merge to form a single one. The transition of the electron motion from regular to chaotic is confirmed by analytical modeling using test electrons moving in counterpropagating planar electromagnetic waves. The findings shed light on the dynamics of wake-bubble collisions and the complex behavior induced by multiple laser pulses in plasmas.

  19. Point-of-injury Use of Reconstituted Freeze Dried Plasma as a Resuscitative Fluid: A Special Report for Prehospital Trauma Care

    Science.gov (United States)

    2013-01-01

    induced by trauma develops in 20% to 30% of combat casualties requiring blood transfusion, with a rise in prevalence with increasing injury severity,7...the patient was extubated within 12 hours and was eventually transferred to a secondary hospital, walking and under antibiotic therapy. DISCUSSION While...Spoerke NJ, Hamilton GJ, Cho SD, Watson K, et al. The use of lyophilized plasma in a severe multi-injury pig model. Transfusion. 2013;53(Suppl 1):72SY79S

  20. Bubble dynamics in drinks

    Directory of Open Access Journals (Sweden)

    Broučková Zuzana

    2014-03-01

    Full Text Available This study introduces two physical effects known from beverages: the effect of sinking bubbles and the hot chocolate sound effect. The paper presents two simple „kitchen” experiments. The first and second effects are indicated by means of a flow visualization and microphone measurement, respectively. To quantify the second (acoustic effect, sound records are analyzed using time-frequency signal processing, and the obtained power spectra and spectrograms are discussed.

  1. Quantum Subcritical Bubbles

    Science.gov (United States)

    Uesugi, T.; Morikawa, M.; Shiromizu, T.

    1996-08-01

    We quantize subcritical bubbles which are formed in the weakly first order phase transition. We find that the typical size of the thermal fluctuation reduces in quantum-statistical physics. We estimate the typical size and the amplitude of thermal fluctuations near the critical temperature in the electroweak phase transition using a quantum statistical average. Furthermore, based on our study, we discuss implications for the dynamics of phase transitions.

  2. Popping the filter bubble

    OpenAIRE

    Hughes, Katie; Cronin, G; Welch, L

    2017-01-01

    So-called “fake news” is everywhere and is having a major impact on daily life from politics to education. The rapid growth of information and the numbers of people who can create it means that we need more sophisticated tools to process the news we receive. Join us to learn about different methods you can use to be your own fact checker and pop your filter bubble.

  3. BubbleDeck

    OpenAIRE

    ECT Team, Purdue

    2013-01-01

    Conventional horizontal concrete slabs are heavy that limit their spans. Enhancement of span results in addition of beams that increases the cost of the structure. Thus, there is a need for a technology that will help in increasing the span by reducing weight of the span. BubbleDeck is a revolutionary construction method that virtually eliminates concrete from the middle of a floor slab between columns that does not perform any structural function, thereby dramatically reducing structural dea...

  4. Bubble Formation in Basalt-like Melts

    DEFF Research Database (Denmark)

    Jensen, Martin; Keding, Ralf; Yue, Yuanzheng

    2011-01-01

    The effect of the melting temperature on bubble size and bubble formation in an iron bearing calcium aluminosilicate melt is studied by means of in-depth images acquired by optical microscopy. The bubble size distribution and the total bubble volume are determined by counting the number of bubbles...... spectroscopy analysis of gases liberated during heating of the glass reveals that small bubbles contain predominantly CH4, CO and CO2, whereas large bubbles bear N2, SO2 and H2S. The methodology utilised in this work can, besides mapping the bubbles in a glass, be applied to shed light on the sources of bubble...

  5. Self-organization of hydrogen gas bubbles rising above laser-etched metallic aluminum in a weakly basic aqueous solution.

    Science.gov (United States)

    Barmina, E V; Kuzmin, P G; Shafeev, G A

    2011-10-01

    Self-organization of hydrogen bubbles is reported under etching of metallic Aluminum in a weakly basic solution. The ascending gas bubbles drift to the areas with higher density of bubbles. As a result, ascending bubbles form various stationary structures whose symmetry is determined by the symmetry of the etched area. Bubbles are aligned along the bisectors of the contour of the etched area. The special laser-assisted profiling of the etched area in shape of a vortex induces a torque in the fluid above the etched area. The process is interpreted on the basis of Bernoulli equation.

  6. In Search of the Big Bubble

    Science.gov (United States)

    Simoson, Andrew; Wentzky, Bethany

    2011-01-01

    Freely rising air bubbles in water sometimes assume the shape of a spherical cap, a shape also known as the "big bubble". Is it possible to find some objective function involving a combination of a bubble's attributes for which the big bubble is the optimal shape? Following the basic idea of the definite integral, we define a bubble's surface as…

  7. Trauma Africa

    Directory of Open Access Journals (Sweden)

    Victor Y. Kong

    2013-11-01

    Full Text Available “Major Trauma. Dr. Kong, please come to the Trauma Unit immediately. Dr. Kong, please come to the Trauma Unit immediately.” Even though I have been working at Edendale Hospital as a trauma registrar for over a year, whenever I hear this announcement over the hospital intercom system, my heart beats just a little faster than normal. When I first arrived at Edendale my colleagues told me that the adrenaline rush I would experience after being called out to attend a new emergency would decrease over time, and indeed they were right. However, it is also true to say that on some occasions more than others, it is still felt more strongly than ever.

  8. Paediatric trauma

    African Journals Online (AJOL)

    Trauma Unit, Red Cross War Memorial Children's Hospital, Cape Town ... and international research projects, educational initiatives and advocacy roles on child safety initiatives regarding child injuries as well as child abuse. ... Road traffic.

  9. ABDOMINAL TRAUMA

    Directory of Open Access Journals (Sweden)

    Alojz Pleskovič

    2003-12-01

    Full Text Available Background. The most common cause of abdominal trauma is blunt trauma, gunshot wounds and stab wounds are rare. Most commonly injured organs in abdominal cavity are the spleen and the liver.Conclusions. Early diagnosis is very important and include precise phisical examination and all available diagnostic methods. The final decission about the method of treatmet depends on patients clinical condition, surgeon’s experience and other local conditions.

  10. Bubble measuring instrument and method

    Science.gov (United States)

    Kline-Schoder, Robert (Inventor); Magari, Patrick J. (Inventor)

    2003-01-01

    Method and apparatus are provided for a non-invasive bubble measuring instrument operable for detecting, distinguishing, and counting gaseous embolisms such as bubbles over a selectable range of bubble sizes of interest. A selected measurement volume in which bubbles may be detected is insonified by two distinct frequencies from a pump transducer and an image transducer, respectively. The image transducer frequency is much higher than the pump transducer frequency. The relatively low-frequency pump signal is used to excite bubbles to resonate at a frequency related to their diameter. The image transducer is operated in a pulse-echo mode at a controllable repetition rate that transmits bursts of high-frequency ultrasonic signal to the measurement volume in which bubbles may be detected and then receives the echo. From the echo or received signal, a beat signal related to the repetition rate may be extracted and used to indicate the presence or absence of a resonant bubble. In a preferred embodiment, software control maintains the beat signal at a preselected frequency while varying the pump transducer frequency to excite bubbles of different diameters to resonate depending on the range of bubble diameters selected for investigation.

  11. Electroweak bubble wall speed limit

    Science.gov (United States)

    Bödeker, Dietrich; Moore, Guy D.

    2017-05-01

    In extensions of the Standard Model with extra scalars, the electroweak phase transition can be very strong, and the bubble walls can be highly relativistic. We revisit our previous argument that electroweak bubble walls can "run away," that is, achieve extreme ultrarelativistic velocities γ ~ 1014. We show that, when particles cross the bubble wall, they can emit transition radiation. Wall-frame soft processes, though suppressed by a power of the coupling α, have a significance enhanced by the γ-factor of the wall, limiting wall velocities to γ ~ 1/α. Though the bubble walls can move at almost the speed of light, they carry an infinitesimal share of the plasma's energy.

  12. Droplets, Bubbles and Ultrasound Interactions.

    Science.gov (United States)

    Shpak, Oleksandr; Verweij, Martin; de Jong, Nico; Versluis, Michel

    2016-01-01

    The interaction of droplets and bubbles with ultrasound has been studied extensively in the last 25 years. Microbubbles are broadly used in diagnostic and therapeutic medical applications, for instance, as ultrasound contrast agents. They have a similar size as red blood cells, and thus are able to circulate within blood vessels. Perfluorocarbon liquid droplets can be a potential new generation of microbubble agents as ultrasound can trigger their conversion into gas bubbles. Prior to activation, they are at least five times smaller in diameter than the resulting bubbles. Together with the violent nature of the phase-transition, the droplets can be used for local drug delivery, embolotherapy, HIFU enhancement and tumor imaging. Here we explain the basics of bubble dynamics, described by the Rayleigh-Plesset equation, bubble resonance frequency, damping and quality factor. We show the elegant calculation of the above characteristics for the case of small amplitude oscillations by linearizing the equations. The effect and importance of a bubble coating and effective surface tension are also discussed. We give the main characteristics of the power spectrum of bubble oscillations. Preceding bubble dynamics, ultrasound propagation is introduced. We explain the speed of sound, nonlinearity and attenuation terms. We examine bubble ultrasound scattering and how it depends on the wave-shape of the incident wave. Finally, we introduce droplet interaction with ultrasound. We elucidate the ultrasound-focusing concept within a droplets sphere, droplet shaking due to media compressibility and droplet phase-conversion dynamics.

  13. Do Some Students Need Special Protection From Research on Sex and Trauma? New Evidence for Young Adult Resilience in "Sensitive Topics" Research.

    Science.gov (United States)

    Rinehart, Jenny K; Nason, Erica E; Yeater, Elizabeth A; Miller, Geoffrey F

    2017-01-01

    Institutional review boards (IRBs) have expressed concerns that certain individuals or groups, such as participants who are younger, ethnic minorities, or who have certain psychological or personality traits, may be particularly distressed when participating in "sensitive topics" research. This study examined the effects of several demographic and individual difference factors (i.e., age, sex, ethnicity, religiosity, Big Five personality traits, and baseline psychological distress levels) on reactions to participation in sensitive topics research. Participants were 504 undergraduates who completed an extensive battery of either trauma/sex questionnaires or cognitive tests and rated their positive and negative emotional reactions and the perceived benefits and mental costs of participating. They also compared research participation to normal life stressors. Our findings indicated that individual difference and demographic risk factors do not increase participant distress after participating in sex/trauma research over and above that experienced after participating in traditionally minimal-risk cognitive tasks. Participants generally found research participation less distressing than normal life stressors and even enjoyable.

  14. Na emission and bubble instability in single-bubble sonoluminescence.

    Science.gov (United States)

    Choi, Pak-Kon; Takumori, Keisuke; Lee, Hyang-Bok

    2017-09-01

    Na emission in single-bubble sonoluminescence (SBSL) was observed from 0.1mM sodium dodecyl sulfate (SDS) solution containing a dissolved noble gas at a low acoustic pressure, at which a continuous spectral component was negligible. High-speed shadowgraph movies were captured at a frame rate of 30,000fps, which indicated that bubble dancing is responsible for the Na emission. The measured bubble path length was well correlated with the Na intensity. The disintegration of a daughter bubble followed by immediate coalescence was frequently observed, which may have been the cause of the bubble dancing. A comparison of the Na spectra obtained in SBSL and multibubble SL showed that the conditions under which Na emission is generated are twofold. A narrow component was observed in the Na spectrum in SBSL, while narrow and broad components were observed in MBSL. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Sonoporation from jetting cavitation bubbles

    NARCIS (Netherlands)

    Ohl, C.D.; Arora, M.; Ikink, Roy; de Jong, N.; Versluis, Michel; Delius, Michael; Lohse, Detlef

    2006-01-01

    The fluid dynamic interaction of cavitation bubbles with adherent cells on a substrate is experimentally investigated. We find that the nonspherical collapse of bubbles near to the boundary is responsible for cell detachment. High-speed photography reveals that a wall bounded flow leads to the

  16. Sonoporation from jetting cavitation bubbles

    NARCIS (Netherlands)

    C.-D. Ohl (Claus-Dieter); M. Arora (Manish); R. Ikink (Roy); N. de Jong (Nico); M. Versluis (Michel); M. Delius (Michael); D. Lohse (Detlef)

    2006-01-01

    textabstractThe fluid dynamic interaction of cavitation bubbles with adherent cells on a substrate is experimentally investigated. We find that the nonspherical collapse of bubbles near to the boundary is responsible for cell detachment. High-speed photography reveals that a wall bounded flow leads

  17. Bubble size distribution of foam

    NARCIS (Netherlands)

    den Engelsen, C.W.; den Engelsen, C.W.; Isarin, J.C.; Warmoeskerken, Marinus; Groot Wassink, J.; Groot Wassink, J.

    2002-01-01

    A procedure based upon image analysis has been adopted to study the influence of several physical parameters on bubble size in foam. A procedure has been described to account for the distribution of bubble size. Foam was generated in a rotor-stator mixer. In the present research, the nature of the

  18. Hadron bubbles in nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    Troitskii, M.A.; Khodel' , V.A.

    1983-08-25

    Nonlinear effects in the interaction of hadrons with a nucleus are analyzed. It is shown that K/sup +/ mesons form bubbles in nuclear matter which are similar to electron bubbles in liquid helium. Charged pions produced in collisions of heavy relativistic ions may collect and form droplets approx.5--7 Fm in size containing approx.10/sup 2/ particles.

  19. Mr. Bubble Gum: "Not Now!"

    National Research Council Canada - National Science Library

    1989-01-01

    PreS-Gr 2-- Mr. Bubble Gum is a Level 3 book, the most difficult in this series. In four short stories of varying lengths, an older brother tells about his younger brother Eli, who "sticks to me like bubble gum...

  20. Bubble chamber: colour enhanced tracks

    CERN Multimedia

    1998-01-01

    This artistically-enhanced image of real particle tracks was produced in the Big European Bubble Chamber (BEBC). Liquid hydrogen is used to create bubbles along the paths of the particles as a piston expands the medium. A magnetic field is produced in the detector causing the particles to travel in spirals, allowing charge and momentum to be measured.

  1. Phase diagrams for sonoluminescing bubbles

    NARCIS (Netherlands)

    Hilgenfeldt, Sascha; Lohse, Detlef; Brenner, Michael P.

    1996-01-01

    Sound driven gas bubbles in water can emit light pulses. This phenomenon is called sonoluminescence (SL). Two different phases of single bubble SL have been proposed: diffusively stable and diffusively unstable SL. We present phase diagrams in the gas concentration versus forcing pressure state

  2. Bubble coalescence in breathing DNA

    DEFF Research Database (Denmark)

    Novotný, Tomas; Pedersen, Jonas Nyvold; Ambjörnsson, Tobias

    2007-01-01

    We investigate the coalescence of two DNA bubbles initially located at weak segments and separated by a more stable barrier region in a designed construct of double-stranded DNA. The characteristic time for bubble coalescence and the corresponding distribution are derived, as well...

  3. [Vascular trauma].

    Science.gov (United States)

    Furuya, T; Nobori, M; Tanaka, N

    1999-07-01

    Vascular trauma is essentially acute arterial obstruction, often combined with hemorrhage, fracture, and infection. It can be both life-threatening and limb-threatening and needs an emergency operation. In vascular trauma patient, multiple fracture and organ injury, such as brain, lung, liver, spleen, kidney, or gastrointestinal tract should be evaluated to decide treatment priority. When the pulse distal from the injured site is absent or diminished, vascular trauma is most likely and reconstruction should be accomplished within "the golden time (6-8 hours)". Intimal damage followed by platelet aggregation and thrombus formation will necessitate resection and repair of the site instead of simple thrombectomy. Although autogenous vein is the first choice, artificial graft can be implanted for short segment in non-infected field.

  4. Growing bubbles rising in line

    Directory of Open Access Journals (Sweden)

    John F. Harper

    2001-01-01

    Full Text Available Over many years the author and others have given theories for bubbles rising in line in a liquid. Theory has usually suggested that the bubbles will tend towards a stable distance apart, but experiments have often showed them pairing off and sometimes coalescing. However, existing theory seems not to deal adequately with the case of bubbles growing as they rise, which they do if the liquid is boiling, or is a supersaturated solution of a gas, or simply because the pressure decreases with height. That omission is now addressed, for spherical bubbles rising at high Reynolds numbers. As the flow is then nearly irrotational, Lagrange's equations can be used with Rayleigh's dissipation function. The theory also works for bubbles shrinking as they rise because they dissolve.

  5. Trauma, attachment, and intimate relationships.

    Science.gov (United States)

    Zurbriggen, Eileen L; Gobin, Robyn L; Kaehler, Laura A

    2012-01-01

    Intimate relationships can both affect and be affected by trauma and its sequelae. This special issue highlights research on trauma, attachment, and intimate relationships. Several themes emerged. One theme is the exploration of the associations between a history of trauma and relational variables, with an emphasis on models using these variables as mediators. Given the significance of secure attachment for healthy relationships, it is not surprising that attachment emerges as another theme of this issue. Moreover, a key component of relationships is trust, and so a further theme of this issue is betrayal trauma (J. J. Freyd, 1996 ). As the work included in this special issue makes clear, intimate relationships of all types are important for the psychological health of those exposed to traumatic events. In order to best help trauma survivors and those close to them, it is imperative that research exploring these issues be presented to research communities, clinical practitioners, and the public in general. This special issue serves as one step toward that objective.

  6. Children and Facial Trauma

    Science.gov (United States)

    ... an ENT Doctor Near You Children and Facial Trauma Children and Facial Trauma Patient Health Information News ... staff at newsroom@entnet.org . What is facial trauma? The term facial trauma means any injury to ...

  7. Trauma Fact Sheet

    Science.gov (United States)

    ... NIGMS NIGMS Home > Science Education > Physical Trauma Physical Trauma Tagline (Optional) Middle/Main Content Area PDF Version (572 KB) Other Fact Sheets What is physical trauma? Physical trauma is a serious injury to the ...

  8. Trauma renal

    OpenAIRE

    Pereira Júnior, Gerson Alves; Paganelli, Fernando; Scarpelini, Sandro; Stracieri, Luís Donizetti Silva; Féres, Ornar; Andrade, José Ivan de

    1999-01-01

    Apresentamos uma revisão sobre trauma renal, com ênfase na avaliação radiológica, particularmente com o uso da tomografia computadorizada, que tem se tornado o exame de eleição, ao invés da urografia excretora e arteriografia. O sucesso no tratamento conservador dos pacientes com trauma renal depende de um acurado estadiamento da extensão da lesão, classificado de acordo com a Organ Injury Scaling do Colégio Americano de Cirurgiões. O tratamento conservador não-operatório é seguro e consiste ...

  9. Ballistic trauma

    Directory of Open Access Journals (Sweden)

    Parvathi Devi Munishwar

    2016-01-01

    Full Text Available Gunshot injuries are rather serious but uncommon type of trauma in India. Radiologists can contribute substantially in the evaluation and treatment of patients with gunshot wounds. Foreign bodies that enter a patient as a result of trauma are contaminated and produce a range of symptoms. Oral and maxillofacial gunshot injuries are usually fatal due to close proximity with vital structures. Here, we report a case in which radiographic evidence of foreign bodies in the right orofacial region exposed a history of a gunshot injury. The patient did not have any major complaints except for reduced mouth opening. These foreign bodies were clinically silent for approximately 12 years.

  10. Drops and bubbles in contact with solid surfaces

    CERN Document Server

    Ferrari, Michele

    2012-01-01

    The third volume in a series dedicated to colloids and interfaces, Drops and Bubbles in Contact with Solid Surfaces presents an up-to-date overview of the fundamentals and applications of drops and bubbles and their interaction with solid surfaces. The chapters cover the theoretical and experimental aspects of wetting and wettability, liquid-solid interfacial properties, and spreading dynamics on different surfaces, including a special section on polymers. The book examines issues related to interpretation of contact angle from nano to macro systems. Expert contributors discuss interesting pec

  11. Trauma Theory

    DEFF Research Database (Denmark)

    Pedersen, Bodil Maria

    There are two main trends in psychological approaches to human suffering related to what we term trauma. Although they have their respective limitations both approaches may help us explore and alleviate human suffering. One trend, primarily using concepts like traumatic events and traumatisation...

  12. Eye trauma

    African Journals Online (AJOL)

    2011-02-02

    Feb 2, 2011 ... Industrial workers should be protected by safety glasses but injuries occur nonetheless. Eye trauma is frequent in homes, farms and backyards where safety glasses are not available. Angle-grinders, metal beating, hammering, fence mending, herding animals, forestry, fire fighting and cutting sugar cane ...

  13. TRAUMA SURGERY

    African Journals Online (AJOL)

    deaths due to other trauma types (gunshot wounds, road traffic fatalities and assault) were documented. Ethical approval was obtained from the University of Pretoria, Faculty of Health. Science Research Ethics Committee, prior to commencement of this study. Descriptive statistical analysis was conducted with the aid of a ...

  14. TRAUMA SURGERY

    African Journals Online (AJOL)

    of shock and who require “damage control” surgery are more likely to suffer a worse outcome, particularly when multiple physiological derangements .... Gun shot. 13. 15. Shot gun. 0. 1. Level of injury. Infrarenal. 11. 7. 0.248. Juxtarenal. 2. 7. Suprarenal. 2. 1. Retrohepatic. 2. 2. Trauma scores. RTS (mean). 7.28. 6.44. 0.095.

  15. TRAUMA SURGERY

    African Journals Online (AJOL)

    and track this epidemic. A number of socio-political changes have continued, and these will impact on the trauma patterns seen in the country. Gun control legislation has been enforced since the turn of the millennium, and there have been ongoing attempts to demilitarise society by removing assault weapons. The ongoing ...

  16. The bubble legacy

    Science.gov (United States)

    Hecht, Jeff

    2010-05-01

    Imagine an optics company - let's call it JDS Uniphase - with a market capitalization approaching the gross domestic product (GDP) of Ireland. Now imagine it merging with a laser company - say, SDL - that has a stock valuation of 41bn, higher than the GDP of Costa Rica. Finally, imagine a start-up with 109m in venture capital in its pocket but no product to its name (Novalux) turning down an offer of 500m as insufficient. It may be hard to believe, but these tales are true: they occurred in the year 2000 - an era when the laser, fibre-optics and photonics industries were the darlings of the financial world. Such was the madcap nature of that brief period that survivors call it simply "the bubble".

  17. Bubble size distribution and inner surface in a bubble flow

    Science.gov (United States)

    Žitek, P.; Valenta, V.

    2017-09-01

    This paper follows the reports [4] and gives instructions on how to theoretically determine the bubble size and its distribution using the distribution function of Nukiyama-Tanasawa with friction factors.

  18. Sonochemistry and the acoustic bubble

    CERN Document Server

    Grieser, Franz; Enomoto, Naoya; Harada, Hisashi; Okitsu, Kenji; Yasui, Kyuichi

    2015-01-01

    Sonochemistry and the Acoustic Bubble provides an introduction to the way ultrasound acts on bubbles in a liquid to cause bubbles to collapse violently, leading to localized 'hot spots' in the liquid with temperatures of 5000° celcius and under pressures of several hundred atmospheres. These extreme conditions produce events such as the emission of light, sonoluminescence, with a lifetime of less than a nanosecond, and free radicals that can initiate a host of varied chemical reactions (sonochemistry) in the liquid, all at room temperature. The physics and chemistry behind the p

  19. Partial coalescence of soap bubbles

    Science.gov (United States)

    Harris, Daniel M.; Pucci, Giuseppe; Bush, John W. M.

    2015-11-01

    We present the results of an experimental investigation of the merger of a soap bubble with a planar soap film. When gently deposited onto a horizontal film, a bubble may interact with the underlying film in such a way as to decrease in size, leaving behind a smaller daughter bubble with approximately half the radius of its progenitor. The process repeats up to three times, with each partial coalescence event occurring over a time scale comparable to the inertial-capillary time. Our results are compared to the recent numerical simulations of Martin and Blanchette and to the coalescence cascade of droplets on a fluid bath.

  20. Bubble stimulation efficiency of dinoflagellate bioluminescence.

    Science.gov (United States)

    Deane, Grant B; Stokes, M Dale; Latz, Michael I

    2016-02-01

    Dinoflagellate bioluminescence, a common source of bioluminescence in coastal waters, is stimulated by flow agitation. Although bubbles are anecdotally known to be stimulatory, the process has never been experimentally investigated. This study quantified the flash response of the bioluminescent dinoflagellate Lingulodinium polyedrum to stimulation by bubbles rising through still seawater. Cells were stimulated by isolated bubbles of 0.3-3 mm radii rising at their terminal velocity, and also by bubble clouds containing bubbles of 0.06-10 mm radii for different air flow rates. Stimulation efficiency, the proportion of cells producing a flash within the volume of water swept out by a rising bubble, decreased with decreasing bubble radius for radii less than approximately 1 mm. Bubbles smaller than a critical radius in the range 0.275-0.325 mm did not stimulate a flash response. The fraction of cells stimulated by bubble clouds was proportional to the volume of air in the bubble cloud, with lower stimulation levels observed for clouds with smaller bubbles. An empirical model for bubble cloud stimulation based on the isolated bubble observations successfully reproduced the observed stimulation by bubble clouds for low air flow rates. High air flow rates stimulated more light emission than expected, presumably because of additional fluid shear stress associated with collective buoyancy effects generated by the high air fraction bubble cloud. These results are relevant to bioluminescence stimulation by bubbles in two-phase flows, such as in ship wakes, breaking waves, and sparged bioreactors. Copyright © 2015 John Wiley & Sons, Ltd.

  1. New evidence on the first financial bubble

    NARCIS (Netherlands)

    Frehen, R.G.P.; Goetzmann, W.; Rouwenhorst, K.G.

    2013-01-01

    The Mississippi Bubble, South Sea Bubble and the Dutch Windhandel of 1720 together represent the world's first global financial bubble. We hand-collect cross-sectional price data and investor account data from 1720 to test theories about market bubbles. Our tests suggest that innovation was a key

  2. Aspherical bubble dynamics and oscillation times

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, A.; Noack, J. [Meizinisches Laserzentrum Luebeck (Germany); Chapyak, E.J.; Godwin, R.P. [Los Alamos National Lab., NM (United States)

    1999-06-01

    The cavitation bubbles common in laser medicine are rarely perfectly spherical and are often located near tissue boundaries, in vessels, etc., which introduce aspherical dynamics. Here, novel features of aspherical bubble dynamics are explored by time-resolved photography and numerical simulations. The growth-collapse period of cylindrical bubbles of large aspect ratio (length:diameter {approximately}20) differs only slightly from twice the Rayleigh collapse time for a spherical bubble with an equivalent maximum volume. This fact justifies using the temporal interval between the acoustic signals emitted upon bubble creation and collapse to estimate the maximum bubble volume. As a result, hydrophone measurements can provide an estimate of the bubble size and energy even for aspherical bubbles. The change of the oscillation period of bubbles near solid walls and elastic (tissue-like) boundaries relative to that of isolated spherical bubbles is also investigated.

  3. The Housing Bubble Fact Sheet

    OpenAIRE

    Dean Baker

    2005-01-01

    This paper explains the basic facts about the current housing market. It lays out the evidence that the rise in housing prices constitutes a housing bubble - and explains what can be expected when it inevitably collapses.

  4. Magnetism. Blowing magnetic skyrmion bubbles.

    Science.gov (United States)

    Jiang, Wanjun; Upadhyaya, Pramey; Zhang, Wei; Yu, Guoqiang; Jungfleisch, M Benjamin; Fradin, Frank Y; Pearson, John E; Tserkovnyak, Yaroslav; Wang, Kang L; Heinonen, Olle; te Velthuis, Suzanne G E; Hoffmann, Axel

    2015-07-17

    The formation of soap bubbles from thin films is accompanied by topological transitions. Here we show how a magnetic topological structure, a skyrmion bubble, can be generated in a solid-state system in a similar manner. Using an inhomogeneous in-plane current in a system with broken inversion symmetry, we experimentally "blow" magnetic skyrmion bubbles from a geometrical constriction. The presence of a spatially divergent spin-orbit torque gives rise to instabilities of the magnetic domain structures that are reminiscent of Rayleigh-Plateau instabilities in fluid flows. We determine a phase diagram for skyrmion formation and reveal the efficient manipulation of these dynamically created skyrmions, including depinning and motion. The demonstrated current-driven transformation from stripe domains to magnetic skyrmion bubbles could lead to progress in skyrmion-based spintronics. Copyright © 2015, American Association for the Advancement of Science.

  5. Microstreaming from Sessile Semicylindrical Bubbles

    Science.gov (United States)

    Hilgenfeldt, Sascha; Rallabandi, Bhargav; Guo, Lin; Wang, Cheng

    2014-03-01

    Powerful steady streaming flows result from the ultrasonic driving of microbubbles, in particular when these bubbles have semicylindrical cross section and are positioned in contact with a microfluidic channel wall. We have used this streaming in experiment to develop novel methods for trapping and sorting of microparticles by size, as well as for micromixing. Theoretically, we arrive at an analytical description of the streaming flow field through an asymptotic computation that, for the first time, reconciles the boundary layers around the bubble and along the substrate wall, and also takes into account the oscillation modes of the bubble. This approach gives insight into changes in the streaming pattern with bubble size and driving frequency, including a reversal of the flow direction at high frequencies with potentially useful applications. Present address: Mechanical and Aerospace Engineering, Missouri S &T.

  6. Organizational network in trauma management in Italy

    Directory of Open Access Journals (Sweden)

    Osvaldo Chiara

    2005-10-01

    Full Text Available In Italy, as in other western countries, trauma is a leading cause of death during the first four decades of life, with almost 18.000 of deaths per year. Since 80s organized systems for trauma care, including a pre-hospital emergency medical system and a network of hospitals designated as Trauma Centres, have been developed in north American countries. Effectiveness of trauma systems has been investigated comparing the post-system to the pre-system trauma care with the method of panel evaluation of preventable death rates and comparison of observed survival with expected probability of survival. In Italy, a pre-hospital emergency medical system has been implemented on a national scale, while a trauma network has not been developed. Nowadays, trauma patients are often admitted to the closest hospital, independently from local resources. The Superior Council of Ministry of Health has presented in 2004 a new trauma system model (SIAT based on the recognition in the field of patients with more serious injuries and the transportation to general hospitals with resources and multidisciplinary teams specialized in trauma care (trauma team. The designation of few trauma team hospitals, one highly specialized Centre (CTS and two area Centres (CTZ every two millions of inhabitants allows each Centre to treat at least 250 severe trauma patients per year to increase experience. Less severe injured patients may be treated in non-trauma team acute care facilities, according to the inclusive system model. The development of trauma team services in some Italian hospitals has demonstrated an increase in survival and a decrease in preventable death rate from 42% to 7,6%. Economic studies of Ministry of Health have established that the implementation of a trauma system model on a national scale with a 25% decrease of preventable trauma deaths and disabilities would save 7500 million of euros of public money. Therefore, in our country the concentration of severely

  7. Doughnut-shaped soap bubbles.

    Science.gov (United States)

    Préve, Deison; Saa, Alberto

    2015-10-01

    Soap bubbles are thin liquid films enclosing a fixed volume of air. Since the surface tension is typically assumed to be the only factor responsible for conforming the soap bubble shape, the realized bubble surfaces are always minimal area ones. Here, we consider the problem of finding the axisymmetric minimal area surface enclosing a fixed volume V and with a fixed equatorial perimeter L. It is well known that the sphere is the solution for V=L(3)/6π(2), and this is indeed the case of a free soap bubble, for instance. Surprisingly, we show that for Vbubble is known to be ultimately unstable and, hence, it will eventually lose its axisymmetry by breaking apart in smaller bubbles. Indisputably, however, the topological transition from spherical to toroidal surfaces is mandatory here for obtaining the global solution for this axisymmetric isoperimetric problem. Our result suggests that deformed bubbles with V<αL(3)/6π(2) cannot be stable and should not exist in foams, for instance.

  8. From rational bubbles to crashes

    Science.gov (United States)

    Sornette, D.; Malevergne, Y.

    2001-10-01

    We study and generalize in various ways the model of rational expectation (RE) bubbles introduced by Blanchard and Watson in the economic literature. Bubbles are argued to be the equivalent of Goldstone modes of the fundamental rational pricing equation, associated with the symmetry-breaking introduced by non-vanishing dividends. Generalizing bubbles in terms of multiplicative stochastic maps, we summarize the result of Lux and Sornette that the no-arbitrage condition imposes that the tail of the return distribution is hyperbolic with an exponent μbubble model to arbitrary dimensions d: a number d of market time series are made linearly interdependent via d× d stochastic coupling coefficients. We derive the no-arbitrage condition in this context and, with the renewal theory for products of random matrices applied to stochastic recurrence equations, we extend the theorem of Lux and Sornette to demonstrate that the tails of the unconditional distributions associated with such d-dimensional bubble processes follow power laws, with the same asymptotic tail exponent μmodel and the non-stationary growth rate model) of the RE bubble model that provide two ways of reconciliation with the stylized facts of financial data.

  9. Measuring online social bubbles

    Directory of Open Access Journals (Sweden)

    Dimitar Nikolov

    2015-12-01

    Full Text Available Social media have become a prevalent channel to access information, spread ideas, and influence opinions. However, it has been suggested that social and algorithmic filtering may cause exposure to less diverse points of view. Here we quantitatively measure this kind of social bias at the collective level by mining a massive datasets of web clicks. Our analysis shows that collectively, people access information from a significantly narrower spectrum of sources through social media and email, compared to a search baseline. The significance of this finding for individual exposure is revealed by investigating the relationship between the diversity of information sources experienced by users at both the collective and individual levels in two datasets where individual users can be analyzed—Twitter posts and search logs. There is a strong correlation between collective and individual diversity, supporting the notion that when we use social media we find ourselves inside “social bubbles.” Our results could lead to a deeper understanding of how technology biases our exposure to new information.

  10. Spinal trauma. An imaging approach

    Energy Technology Data Exchange (ETDEWEB)

    Cassar-Pullicino, V.N. [The Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire (United Kingdom). Dept. of Radiology; Imhof, H. [University and General Hospital Vienna (Austria). Dept. of Radiodiagnostics

    2006-07-01

    The diagnosis of trauma to the spine - where the slightest oversight may have catastrophic results - requires a thorough grasp of the spectrum of resultant pathology as well as the imaging modalities used in making an accurate diagnosis. In Spinal Trauma, the internationally renowned team of experts provides a comprehensive, cutting-edge exposition of the current vital role of imaging in the diagnosis and treatment of injuries to the axial skeleton. Beginning with a valuable clinical perspective of spinal trauma, the book offers the reader a unique overview of the biomechanics underlying the pathology of cervical trauma. Acute trauma topics include: - Optimization of imaging modalities - Malalignment - signs and significance - Vertebral fractures - detection and implications - Classification of thoraco-lumbar fractures - rationale and relevance - Neurovascular injury. Distilling decades of clinical and teaching expertise, the contributors further discuss the current role of imaging in special focus topics, which include: - The pediatric spine - Sports injuries - The rigid spine - Trauma in the elderly - Vertebral collapse, benign and malignant - Spinal trauma therapy - Vertebral fractures and osteoporosis - Neuropathic spine. All throughout the book, the focus is on understanding the injury, and its implications and complications, through 'an imaging approach'. Lavishly illustrated with hundreds of superb MR images and CT scans, and clear full-color drawings, the authors conclude with a look into the future, defining clinical trends and research directions. Spinal Trauma - with its broad scope, practical imaging approach, and current focus - is designed to enhance confidence and accuracy, making it essential reading for clinicians and radiologists at all levels. (orig.)

  11. FEASTING BLACK HOLE BLOWS BUBBLES

    Science.gov (United States)

    2002-01-01

    A monstrous black hole's rude table manners include blowing huge bubbles of hot gas into space. At least, that's the gustatory practice followed by the supermassive black hole residing in the hub of the nearby galaxy NGC 4438. Known as a peculiar galaxy because of its unusual shape, NGC 4438 is in the Virgo Cluster, 50 million light-years from Earth. These NASA Hubble Space Telescope images of the galaxy's central region clearly show one of the bubbles rising from a dark band of dust. The other bubble, emanating from below the dust band, is barely visible, appearing as dim red blobs in the close-up picture of the galaxy's hub (the colorful picture at right). The background image represents a wider view of the galaxy, with the central region defined by the white box. These extremely hot bubbles are caused by the black hole's voracious eating habits. The eating machine is engorging itself with a banquet of material swirling around it in an accretion disk (the white region below the bright bubble). Some of this material is spewed from the disk in opposite directions. Acting like high-powered garden hoses, these twin jets of matter sweep out material in their paths. The jets eventually slam into a wall of dense, slow-moving gas, which is traveling at less than 223,000 mph (360,000 kph). The collision produces the glowing material. The bubbles will continue to expand and will eventually dissipate. Compared with the life of the galaxy, this bubble-blowing phase is a short-lived event. The bubble is much brighter on one side of the galaxy's center because the jet smashed into a denser amount of gas. The brighter bubble is 800 light-years tall and 800 light-years across. The observations are being presented June 5 at the American Astronomical Society meeting in Rochester, N.Y. Both pictures were taken March 24, 1999 with the Wide Field and Planetary Camera 2. False colors were used to enhance the details of the bubbles. The red regions in the picture denote the hot gas

  12. BUBBLE FORMATION EXPERIMENTS IN SNOW DENSIFICATION

    OpenAIRE

    イシイ, セイゴ; ナリタ, ヒデキ; マエノ, ノリカズ; Seigo, ISHII; Hideki, NARITA; Norikazu, MAENO

    1995-01-01

    Bubble formation experiments were conducted for snow composed of ice spheres 303μm in diameter at various temperatures and applied pressures. By measuring volumes of closed-off bubbles at various densities, the bubble formation density (ρ_f) and the bubble close-off density (ρ_c) were obtained. ρ_f, that is the density at which bubble formation begins, decreased with lowering temperature or pressure. On the other hand, ρ_c, that is the density at which bubble formation finishes, increased wit...

  13. Spherical Solutions of an Underwater Explosion Bubble

    Directory of Open Access Journals (Sweden)

    Andrew B. Wardlaw

    1998-01-01

    Full Text Available The evolution of the 1D explosion bubble flow field out to the first bubble minimum is examined in detail using four different models. The most detailed is based on the Euler equations and accounts for the internal bubble fluid motion, while the simplest links a potential water solution to a stationary, Isentropic bubble model. Comparison of the different models with experimental data provides insight into the influence of compressibility and internal bubble dynamics on the behavior of the explosion bubble.

  14. On the Inception of Financial Representative Bubbles

    Directory of Open Access Journals (Sweden)

    Massimiliano Ferrara

    2017-11-01

    Full Text Available In this work, we aim to formalize the inception of representative bubbles giving the condition under which they may arise. We will find that representative bubbles may start at any time, depending on the definition of a behavioral component. This result is at odds with the theory of classic rational bubbles, which are those models that rely on the fulfillment of the transversality condition by which a bubble in a financial asset can arise just at its first trade. This means that a classic rational bubble (differently from our model cannot follow a cycle since if a bubble exists, it will burst by definition and never arise again.

  15. Ventilatory strategies in trauma patients

    Directory of Open Access Journals (Sweden)

    Shubhangi Arora

    2014-01-01

    Full Text Available Lung injury in trauma patients can occur because of direct injury to lung or due to secondary effects of injury elsewhere for example fat embolism from a long bone fracture, or due to response to a systemic insult such as; acute respiratory distress syndrome (ARDS secondary to sepsis or transfusion related lung injury. There are certain special situations like head injury where the primary culprit is not the lung, but the brain and the ventilator strategy is aimed at preserving the brain tissue and the respiratory system takes a second place. The present article aims to delineate the strategies addressing practical problems and challenges faced by intensivists dealing with trauma patients with or without healthy lungs. The lung protective strategies along with newer trends in ventilation are discussed. Ventilatory management for specific organ system trauma are highlighted and their physiological base is presented.

  16. Understanding bubble dynamics in a chemically stratified, bi-liquid, micro-droplet system

    OpenAIRE

    Phatak, Neeti

    2016-01-01

    In special liquid-liquid, chemically stratified, micro-fluidic, lab-on-a-chip (LOC) systems, used in biological applications, rare bubble evolutions occur at temperatures far below the boiling point of the analyte solution, leading to erroneous analysis. The current, mainly experimental work, aims in providing a physical understanding to the above, and in closing, proposing solutions for the elimination/control of bubbles- for the overall betterment of such systems. The characterization of...

  17. Bubble rearrangements dynamics in foams

    Science.gov (United States)

    Le Merrer, Marie; Costa, Severine; Cohen-Addad, Sylvie; Hoehler, Reinhard

    2011-11-01

    Liquid foams are jammed dispersions of gas bubbles in a surfactant solution. Their structure evolves with time because surface tension drives a diffusive gas exchange between neighboring bubbles. This coarsening leads to a build-up of stresses which are relaxed upon local intermittent bubble rearrangements. These events govern the slow viscoelastic foam response, and similar bubble rearrangements are the elementary processes of plastic flow. Thus, the rearrangement duration is a key parameter describing how the microstructure dynamics control the macroscopic rheological response. We probe the duration of coarsening-induced rearrangements in 3D foams using a multiple light scattering technique (time resolved Diffusing-Wave Spectroscopy) as a function of the surfactant chemistry and the liquid fraction. As the foam becomes wetter, the confinement pressure of the packing goes to zero and the contacts between bubbles vanish. For mobile interfaces, we find that the rearrangements slow down as the jamming point is approached. These findings are compared to scaling laws which reveal an analogy between rearrangements dynamics in foams and granular suspensions.

  18. Ethnic diversity deflates price bubbles

    Science.gov (United States)

    Levine, Sheen S.; Apfelbaum, Evan P.; Bernard, Mark; Bartelt, Valerie L.; Zajac, Edward J.; Stark, David

    2014-01-01

    Markets are central to modern society, so their failures can be devastating. Here, we examine a prominent failure: price bubbles. Bubbles emerge when traders err collectively in pricing, causing misfit between market prices and the true values of assets. The causes of such collective errors remain elusive. We propose that bubbles are affected by ethnic homogeneity in the market and can be thwarted by diversity. In homogenous markets, traders place undue confidence in the decisions of others. Less likely to scrutinize others’ decisions, traders are more likely to accept prices that deviate from true values. To test this, we constructed experimental markets in Southeast Asia and North America, where participants traded stocks to earn money. We randomly assigned participants to ethnically homogeneous or diverse markets. We find a marked difference: Across markets and locations, market prices fit true values 58% better in diverse markets. The effect is similar across sites, despite sizeable differences in culture and ethnic composition. Specifically, in homogenous markets, overpricing is higher as traders are more likely to accept speculative prices. Their pricing errors are more correlated than in diverse markets. In addition, when bubbles burst, homogenous markets crash more severely. The findings suggest that price bubbles arise not only from individual errors or financial conditions, but also from the social context of decision making. The evidence may inform public discussion on ethnic diversity: it may be beneficial not only for providing variety in perspectives and skills, but also because diversity facilitates friction that enhances deliberation and upends conformity. PMID:25404313

  19. Ethnic diversity deflates price bubbles.

    Science.gov (United States)

    Levine, Sheen S; Apfelbaum, Evan P; Bernard, Mark; Bartelt, Valerie L; Zajac, Edward J; Stark, David

    2014-12-30

    Markets are central to modern society, so their failures can be devastating. Here, we examine a prominent failure: price bubbles. Bubbles emerge when traders err collectively in pricing, causing misfit between market prices and the true values of assets. The causes of such collective errors remain elusive. We propose that bubbles are affected by ethnic homogeneity in the market and can be thwarted by diversity. In homogenous markets, traders place undue confidence in the decisions of others. Less likely to scrutinize others' decisions, traders are more likely to accept prices that deviate from true values. To test this, we constructed experimental markets in Southeast Asia and North America, where participants traded stocks to earn money. We randomly assigned participants to ethnically homogeneous or diverse markets. We find a marked difference: Across markets and locations, market prices fit true values 58% better in diverse markets. The effect is similar across sites, despite sizeable differences in culture and ethnic composition. Specifically, in homogenous markets, overpricing is higher as traders are more likely to accept speculative prices. Their pricing errors are more correlated than in diverse markets. In addition, when bubbles burst, homogenous markets crash more severely. The findings suggest that price bubbles arise not only from individual errors or financial conditions, but also from the social context of decision making. The evidence may inform public discussion on ethnic diversity: it may be beneficial not only for providing variety in perspectives and skills, but also because diversity facilitates friction that enhances deliberation and upends conformity.

  20. Trauma renal

    Directory of Open Access Journals (Sweden)

    Gerson Alves Pereira Júnior

    Full Text Available Apresentamos uma revisão sobre trauma renal, com ênfase na avaliação radiológica, particularmente com o uso da tomografia computadorizada, que tem se tornado o exame de eleição, ao invés da urografia excretora e arteriografia. O sucesso no tratamento conservador dos pacientes com trauma renal depende de um acurado estadiamento da extensão da lesão, classificado de acordo com a Organ Injury Scaling do Colégio Americano de Cirurgiões. O tratamento conservador não-operatório é seguro e consiste de observação contínua, repouso no leito, hidratação endovenosa adequada e antibioti- coterapia profilática, evitando-se uma exploração cirúrgica desnecessária e possível perda renal. As indicações para exploração cirúrgica imediata são abdome agudo, rápida queda do hematócrito ou lesões associadas determinadas na avaliação radiológica. Quando indicada, a exploração renal após controle vascular prévio é segura, permitindo cuidadosa inspeção do rim e sua reconstrução com sucesso, reduzindo a probabilidade de nefrectomia.

  1. Aspherical bubble dynamics and oscillation times

    Energy Technology Data Exchange (ETDEWEB)

    Godwin, R.P.; Chapyak, E.J. [Los Alamos National Lab., NM (United States); Noack, J.; Vogel, A. [Medizinisches Laserzentrum Luebeck (Germany)

    1999-03-01

    The cavitation bubbles common in laser medicine are rarely perfectly spherical and are often located near tissue boundaries, in vessels, etc., which introduce aspherical dynamics. Here, novel features of aspherical bubble dynamics are explored. Time-resolved experimental photographs and simulations of large aspect ratio (length:diameter {approximately}20) cylindrical bubble dynamics are presented. The experiments and calculations exhibit similar dynamics. A small high-pressure cylindrical bubble initially expands radially with hardly any axial motion. Then, after reaching its maximum volume, a cylindrical bubble collapses along its long axis with relatively little radial motion. The growth-collapse period of these very aspherical bubbles differs only sightly from twice the Rayleigh collapse time for a spherical bubble with an equivalent maximum volume. This fact justifies using the temporal interval between the acoustic signals emitted upon bubble creation and collapse to estimate the maximum bubble volume. As a result, hydrophone measurements can provide an estimate of the bubble energy even for aspherical bubbles. The prolongation of the oscillation period of bubbles near solid boundaries relative to that of isolated spherical bubbles is also discussed.

  2. Trauma Severity at Level 2 Trauma Center – Attainability of Retrospective Documentation on Severity

    DEFF Research Database (Denmark)

    Hebsgaard, Stine; Zwisler, Stine Thorhauge; Lauritsen, Jens M

    2015-01-01

    Abstract Background: Centralizing and specializing in Danish health care is ongoing. Around the country Mobile Emergency Care Units (MECU) are introduced during the past years. Pre-hospital triage is important to evaluate at which trauma level the severely injured patients must be received. The aim...... of our study was to evaluate changes in the severity in adult traffic related high injury traumas admitted to a level 2 trauma center at Odense University Hospital, Svendborg Hospital (OUH-SH) during the last decade and before and after the introduction of the local MECU through the years 2007...... month. Based on clinical record reviews and radiology findings, we decided if the patient was Multi Trauma (MT) defined as received by trauma response team and/or CT trauma scanned. Diagnoses were evaluated and maximum Abbreviated Injury Score (mAIS) was assigned dividing patients in severe injured...

  3. Soap Bubbles on a Cold Day.

    Science.gov (United States)

    Waiveris, Charles

    1994-01-01

    Discusses the effects of blowing bubbles in extremely cold weather. Describes the freezing conditions of the bubbles and some physical properties. Suggests using the activity with all ages of students. (MVL)

  4. Unorthodox bubbles when boiling in cold water

    Science.gov (United States)

    Parker, Scott; Granick, Steve

    2014-01-01

    High-speed movies are taken when bubbles grow at gold surfaces heated spotwise with a near-infrared laser beam heating water below the boiling point (60-70 °C) with heating powers spanning the range from very low to so high that water fails to rewet the surface after bubbles detach. Roughly half the bubbles are conventional: They grow symmetrically through evaporation until buoyancy lifts them away. Others have unorthodox shapes and appear to contribute disproportionately to heat transfer efficiency: mushroom cloud shapes, violently explosive bubbles, and cavitation events, probably stimulated by a combination of superheating, convection, turbulence, and surface dewetting during the initial bubble growth. Moreover, bubbles often follow one another in complex sequences, often beginning with an unorthodox bubble that stirs the water, followed by several conventional bubbles. This large dataset is analyzed and discussed with emphasis on how explosive phenomena such as cavitation induce discrepancies from classical expectations about boiling.

  5. Bubble nucleation in an explosive micro-bubble actuator

    NARCIS (Netherlands)

    van den Broek, D.M.; Elwenspoek, Michael Curt

    2008-01-01

    Explosive evaporation occurs when a thin layer of liquid reaches a temperature close to the critical temperature in a very short time. At these temperatures spontaneous nucleation takes place. The nucleated bubbles instantly coalesce forming a vapour film followed by rapid growth due to the pressure

  6. Does monetary policy generate asset price bubbles ?

    OpenAIRE

    Blot, Christophe; Hubert, Paul; Labondance, Fabien

    2017-01-01

    This paper empirically assesses the effect of monetary policy on asset price bubbles and aims to disentangle the competing predictions of theoretical bubble models. First, we take advantage of the model averaging feature of Principal Component Analysis to estimate bubble indicators, for the stock, bond and housing markets in the United States and Euro area, based on the structural, econometric and statistical approaches proposed in the literature to measure bubbles. Second, we ...

  7. Eulerian simulations of bubble behaviour in a two-dimensional gas-solid bubbling fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Lu Huilin; Liu Wentie; Zhao Guangbo; He Yurong [Harbin Institute of Technology (China). Dept. of Power Engineering; Li Feng [Jiangxi Boiler Co. Ltd., Nanchang (China)

    2002-07-01

    In the present study, the CFD model is based on a two-fluid model extended with the kinetic theory of granular flow. The simulation results of bubble diameter and bubble rise velocity are compared to the Darton equation and the Davidson model in a free bubbling fluidized bed. The predicted values are in reasonable agreement with the values from the Darton bubble size equation and the Davidson model for isolated bubbles. It is shown that the break-up and direct wall interaction effects influence the dynamic bubble behavior in the free bubbling fluidized beds. (author)

  8. Interfacial instability of a condensing vapor bubble in a subcooled liquid

    Science.gov (United States)

    Ueno, I.; Ando, J.; Koiwa, Y.; Saiki, T.; Kaneko, T.

    2015-03-01

    A special attention is paid to the condensing and collapsing processes of vapor bubble injected into a subcooled pool. We try to extract the vapor-liquid interaction by employing a vapor generator that supplies vapor to the subcooled pool through an orifice instead of using a immersed heating surface to realize vapor bubbles by boiling phenomenon. This system enables ones to detect a spatio-temporal behavior of a single bubble of superheated vapor exposed to a subcooled liquid. In the present study, vapor of water is injected through an orifice at constant flow rate to the subcooled pool of water at the designated degree of subcooling under the atmospheric pressure. The degree of subcooling of the pool is ranged from 0 K to 70 K, and the vapor temperature is kept constant at 101 ∘C. The behaviors of the injected vapor are captured by high-speed camera at frame rate up to 0.3 million frame per second (fps) to track the temporal variation of the vapor bubble shape. It is found that the abrupt collapse of the vapor bubble exposed to the subcooled pool takes place under the condition that the degree of subcooling is greater than around 30 K, and that the abrupt collapse always takes place accompanying the fine disturbances or instability emerged on the free surface. We then evaluate a temporal variation of the apparent `volume' of the bubble V under the assumption of the axisymmetric shape of the vapor bubble. It is also found that the instability emerges slightly after the volume of the vapor bubble reaches the maximum value. It is evaluated that the second derivative of the corresponding `radius' R of the vapor bubble is negative when the instability appears on the bubble surface, where R = 3√ 3V/4π. We also illustrate that the wave number of the instability on the liquid-vapor interface increases as the degree of subcooling.

  9. Behavior of a Large Bubble in a Horizontal Channel : 2nd Report, Large Bubble Penetrating into Running Liquid

    OpenAIRE

    坂口, 忠司; 小澤, 守; 浜口, 八朗; 福永, 毅

    1990-01-01

    The behavior of a large bubble penetrating into running liquid in a horizontal pipe has been studied experimentally. The flow regime of the large bubble is classified into the following three regimes : a steadily moving bubble regime, a transition regime and a stationary bubble regime. In the steadily moving bubble regime, the large bubble penetrates at constant velocity and the shape of the bubble nose does not change along the pipe. An analysis of the behavior of the large bubble has been c...

  10. Vapor Bubbles in Flow and Acoustic Fields

    NARCIS (Netherlands)

    Prosperetti, Andrea; Hao, Yue; Sadhal, S.S

    2002-01-01

    A review of several aspects of the interaction of bubbles with acoustic and flow fields is presented. The focus of the paper is on bubbles in hot liquids, in which the bubble contains mostly vapor, with little or no permanent gas. The topics covered include the effect of translation on condensation

  11. Bubble Size Distributions in Coastal Seas

    NARCIS (Netherlands)

    Leeuw, G. de; Cohen, L.H.

    1995-01-01

    Bubble size distributions have been measured with an optical system that is based on imaging of a small sample volume with a CCD camera system, and processing of the images to obtain the size of individual bubbles in the diameter range from 30 to lOOO^m. This bubble measuring system is deployed from

  12. Mechanics of gas-vapor bubbles

    NARCIS (Netherlands)

    Hao, Yue; Zhang, Yuhang; Prosperetti, Andrea

    2017-01-01

    Most bubbles contain a mixture of vapor and incondensible gases. While the limit cases of pure vapor and pure gas bubbles are well studied, much less is known about the more realistic case of a mixture. The bubble contents continuously change due to the combined effects of evaporation and

  13. Frictional drag reduction by bubble injection

    Science.gov (United States)

    Murai, Yuichi

    2014-07-01

    The injection of gas bubbles into a turbulent boundary layer of a liquid phase has multiple different impacts on the original flow structure. Frictional drag reduction is a phenomenon resulting from their combined effects. This explains why a number of different void-drag reduction relationships have been reported to date, while early works pursued a simple universal mechanism. In the last 15 years, a series of precisely designed experimentations has led to the conclusion that the frictional drag reduction by bubble injection has multiple manifestations dependent on bubble size and flow speed. The phenomena are classified into several regimes of two-phase interaction mechanisms. Each regime has inherent physics of bubbly liquid, highlighted by keywords such as bubbly mixture rheology, the spectral response of bubbles in turbulence, buoyancy-dominated bubble behavior, and gas cavity breakup. Among the regimes, bubbles in some selected situations lose the drag reduction effect owing to extra momentum transfer promoted by their active motions. This separates engineers into two communities: those studying small bubbles for high-speed flow applications and those studying large bubbles for low-speed flow applications. This article reviews the roles of bubbles in drag reduction, which have been revealed from fundamental studies of simplified flow geometries and from development of measurement techniques that resolve the inner layer structure of bubble-mixed turbulent boundary layers.

  14. Affirmative Discrimination and the Bubble

    Science.gov (United States)

    Clegg, Roger

    2011-01-01

    In this essay, the author discusses how affirmative action contributed to an unnatural rise in enrollments in college. In considering the higher education bubble, he makes the case that as the opposition to preferences continues to build, the momentum of this trend will only increase as funding shrinks. He offers some tentative answers to a series…

  15. The Coming Law School Bubble

    Science.gov (United States)

    Krauss, Michael I.

    2011-01-01

    In this article, the author explains how forty years of politicized hiring in the law schools has left its destructive mark. The results are potentially catastrophic: Market forces and internal law school policies may be combining to produce a legal education bubble the likes of which the country has never seen. (Contains 11 footnotes.)

  16. Models of cylindrical bubble pulsation

    Science.gov (United States)

    Ilinskii, Yurii A.; Zabolotskaya, Evgenia A.; Hay, Todd A.; Hamilton, Mark F.

    2012-01-01

    Three models are considered for describing the dynamics of a pulsating cylindrical bubble. A linear solution is derived for a cylindrical bubble in an infinite compressible liquid. The solution accounts for losses due to viscosity, heat conduction, and acoustic radiation. It reveals that radiation is the dominant loss mechanism, and that it is 22 times greater than for a spherical bubble of the same radius. The predicted resonance frequency provides a basis of comparison for limiting forms of other models. The second model considered is a commonly used equation in Rayleigh-Plesset form that requires an incompressible liquid to be finite in extent in order for bubble pulsation to occur. The radial extent of the liquid becomes a fitting parameter, and it is found that considerably different values of the parameter are required for modeling inertial motion versus acoustical oscillations. The third model was developed by V. K. Kedrinskii [Hydrodynamics of Explosion (Springer, New York, 2005), pp. 23–26] in the form of the Gilmore equation for compressible liquids of infinite extent. While the correct resonance frequency and loss factor are not recovered from this model in the linear approximation, it provides reasonable agreement with observations of inertial motion. PMID:22978863

  17. The Big European Bubble Chamber

    CERN Multimedia

    1977-01-01

    The 3.70 metre Big European Bubble Chamber (BEBC), dismantled on 9 August 1984. During operation it was one of the biggest detectors in the world, producing direct visual recordings of particle tracks. 6.3 million photos of interactions were taken with the chamber in the course of its existence.

  18. Explosive micro-bubble actuator

    NARCIS (Netherlands)

    van den Broek, D.M.; Elwenspoek, Michael Curt

    2007-01-01

    Explosive evaporation occurs when a thin layer of liquid reaches a very high temperature in a very short time. At these temperatures homogeneous nucleation takes place. The nucleated bubbles almost instantly coalesce forming a vapour film followed by rapid growth due to the pressure impulse and

  19. Droplets, Bubbles and Ultrasound Interactions

    NARCIS (Netherlands)

    Shpak, O.; Verweij, M.; de Jong, N.; Versluis, Michel; Escoffre, J.M.; Bouakaz, A.

    2016-01-01

    The interaction of droplets and bubbles with ultrasound has been studied extensively in the last 25 years. Microbubbles are broadly used in diagnostic and therapeutic medical applications, for instance, as ultrasound contrast agents. They have a similar size as red blood cells, and thus are able to

  20. Electrolysis Bubbles Make Waterflow Visible

    Science.gov (United States)

    Schultz, Donald F.

    1990-01-01

    Technique for visualization of three-dimensional flow uses tiny tracer bubbles of hydrogen and oxygen made by electrolysis of water. Strobe-light photography used to capture flow patterns, yielding permanent record that is measured to obtain velocities of particles. Used to measure simulated mixing turbulence in proposed gas-turbine combustor and also used in other water-table flow tests.

  1. Impurity bubbles in a BEC

    Science.gov (United States)

    Timmermans, Eddy; Blinova, Alina; Boshier, Malcolm

    2013-05-01

    Polarons (particles that interact with the self-consistent deformation of the host medium that contains them) self-localize when strongly coupled. Dilute Bose-Einstein condensates (BECs) doped with neutral distinguishable atoms (impurities) and armed with a Feshbach-tuned impurity-boson interaction provide a unique laboratory to study self-localized polarons. In nature, self-localized polarons come in two flavors that exhibit qualitatively different behavior: In lattice systems, the deformation is slight and the particle is accompanied by a cloud of collective excitations as in the case of the Landau-Pekar polarons of electrons in a dielectric lattice. In natural fluids and gases, the strongly coupled particle radically alters the medium, e.g. by expelling the host medium as in the case of the electron bubbles in superfluid helium. We show that BEC-impurities can self-localize in a bubble, as well as in a Landau-Pekar polaron state. The BEC-impurity system is fully characterized by only two dimensionless coupling constants. In the corresponding phase diagram the bubble and Landau-Pekar polaron limits correspond to large islands separated by a cross-over region. The same BEC-impurity species can be adiabatically Feshbach steered from the Landau-Pekar to the bubble regime. This work was funded by the Los Alamos LDRD program.

  2. "Financial Bubbles" and Monetary Policy

    Science.gov (United States)

    Tikhonov, Yuriy A.; Pudovkina, Olga E.; Permjakova, Juliana V.

    2016-01-01

    The relevance of this research is caused by the need of strengthening a role of monetary regulators to prevent financial bubbles in the financial markets. The aim of the article is the analysis of a problem of crisis phenomena in the markets of financial assets owing to an inadequate growth of their cost, owing to subjective reasons. The leading…

  3. Bubble bouncing at a clean water surface.

    Science.gov (United States)

    Zawala, Jan; Dorbolo, Stéphane; Vandewalle, Nicolas; Malysa, Kazimierz

    2013-10-28

    Experiments on the coalescence time of submillimeter bubbles colliding with a distilled water/air interface either being at rest (undisturbed) or vibrating vertically (with controlled amplitude and frequency) were carried out. It was found that the outcome of the bubble collision (coalescence or bounce) depends on impact velocity and size of the bubble, i.e. the parameters determining the bubble deformation degree. With the surface at rest, when the deformation of the bubble was sufficiently high, bubble bouncing was observed. It was caused by the fact that the radius of the intervening liquid film formed between the colliding bubble and water/air interface was large enough to prevent the liquid layer from reaching its thickness of rupture within the time of bubble-interface contact. Coalescence occurred in a consecutive collision if the bubble deformation was below a threshold value, as a result of dissipation of the kinetic energy associated with the bubble motion. The hypothesis about the crucial role of the bubble deformation and size of the liquid film formed in the bouncing mechanism was confirmed in a series of experiments where the bubble collided with a vibrating water/air interface. It was shown that when the kinetic energy was properly re-supplied from an external source (interface vibrations), the spectacular phenomenon of "immortal" bubbles, dancing indefinitely at the water/air interface, was achieved. It was shown that "immortal" bubble formation is a consequence of a similarly high degree of the bubble shape deformation and consequently a large enough radius of the liquid film formed.

  4. Robust acoustic wave manipulation of bubbly liquids

    Energy Technology Data Exchange (ETDEWEB)

    Gumerov, N. A., E-mail: gumerov@umiacs.umd.edu [Institute for Advanced Computer Studies, University of Maryland, College Park, Maryland 20742 (United States); Center for Micro- and Nanoscale Dynamics of Dispersed Systems, Bashkir State University, Ufa 450076 (Russian Federation); Akhatov, I. S. [Center for Design, Manufacturing and Materials, Skolkovo Institute of Science and Technology, Moscow 143026 (Russian Federation); Ohl, C.-D. [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore); Center for Micro- and Nanoscale Dynamics of Dispersed Systems, Bashkir State University, Ufa 450076 (Russian Federation); Sametov, S. P. [Center for Micro- and Nanoscale Dynamics of Dispersed Systems, Bashkir State University, Ufa 450076 (Russian Federation); Khazimullin, M. V. [Center for Micro- and Nanoscale Dynamics of Dispersed Systems, Bashkir State University, Ufa 450076 (Russian Federation); Institute of Molecule and Crystal Physics, Ufa Research Center of Russian Academy of Sciences, Ufa 450054 (Russian Federation); Gonzalez-Avila, S. R. [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)

    2016-03-28

    Experiments with water–air bubbly liquids when exposed to acoustic fields of frequency ∼100 kHz and intensity below the cavitation threshold demonstrate that bubbles ∼30 μm in diameter can be “pushed” away from acoustic sources by acoustic radiation independently from the direction of gravity. This manifests formation and propagation of acoustically induced transparency waves (waves of the bubble volume fraction). In fact, this is a collective effect of bubbles, which can be described by a mathematical model of bubble self-organization in acoustic fields that matches well with our experiments.

  5. Bubbles generated from wind-steepened breaking waves: 2. Bubble plumes, bubbles, and wave characteristics

    NARCIS (Netherlands)

    Leifer, I.; Caulliez, G.; Leeuw, G.de

    2006-01-01

    Measurements of breaking-wave-generated bubble plumes were made in fresh (but not clean) water in a large wind-wave tunnel. To preserve diversity, a classification scheme was developed on the basis of plume dimensions and "optical density," or the plume's ability to obscure the background. Optically

  6. Simulations of Rising Hydrodynamic and Magnetohydrodynamic Bubbles

    Science.gov (United States)

    Ricker, P. M.; Robinson, K.; Dursi, L. J.; Rosner, R.; Calder, A. C.; Zingale, M.; Truran, J. W.; Linde, T.; Caceres, A.; Fryxell, B.; Olson, K.; Riley, K.; Siegel, A.; Vladimirova, N.

    Motivated by recent Chandra and XMM-Newton observations of X-ray emission voids in galaxy cluster cooling flows, we have investigated the behavior of rising bubbles in stratified atmospheres using the FLASH adaptive-mesh simulation code. We present results from two-dimensional simulations with and without the effects of magnetic fields, and with varying bubble sizes and background stratifications. We find purely hydrodynamic bubbles to be unstable; a dynamically important magnetic field is required to maintain a bubble's integrity. This suggests that, even absent thermal conduction, for bubbles to be persistent enough to be regularly observed, they must be supported in large part by magnetic fields. We also observe that magnetically supported bubbles leave a tail as they rise. The structure of these tails may provide clues to the bubble's dynamical history.

  7. Bubbles and fingers in a Hele-Shaw cell: steady solutions

    CERN Document Server

    Vasconcelos, Giovani L

    2015-01-01

    Analytical solutions for both a finite assembly and a periodic array of bubbles steadily moving in a Hele-Shaw channel are presented. The particular case of multiple fingers penetrating into the channel and moving jointly with an assembly of bubbles is also analysed. The solutions are given by a conformal mapping from a multiply connected circular domain in an auxiliary complex plane to the fluid region exterior to the bubbles. In all cases the desired mapping is written explicitly in terms of certain special transcendental functions, known as the secondary Schottky-Klein prime functions. Taken together, the solutions reported here represent the complete set of solutions for steady bubbles (and fingers) in a horizontal Hele-Shaw channel when surface tension is neglected. All previous solutions under these assumptions are particular cases of the general solutions reported here. Other possible applications of the formalism described here are also discussed.

  8. INTERACTIONS OF THE INFRARED BUBBLE N4 WITH ITS SURROUNDINGS

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hong-Li; Li, Jin-Zeng; Yuan, Jing-Hua; Huang, Maohai; Huang, Ya-Fang; Zhang, Si-Ju [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Wu, Yuefang [Department of Astronomy, Peking University, 100871 Beijing (China); Liu, Tie [Korea Astronomy and Space Science Institute 776, Daedeokdae-ro, Yuseong-gu, Daejeon, 305-348 (Korea, Republic of); Dubner, G.; Paron, S.; Ortega, M. E. [1Instituto de Astronomía y Física del Espacio (IAFE, CONICET-UBA), CC 67, Suc. 28, 1428 Buenos Aires (Argentina); Molinari, Sergio [Istituto di Astrofisica e Planetologia Spaziali—IAPS, Istituto Nazionale di Astrofisica—INAF, via Fosso del Cavaliere 100, I-00133 Roma (Italy); Zavagno, Annie; Samal, Manash R., E-mail: hlliu@nao.cas.cn [Aix Marseille Universit, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, F-13388, Marseille (France)

    2016-02-10

    The physical mechanisms that induce the transformation of a certain mass of gas in new stars are far from being well understood. Infrared bubbles associated with H ii regions have been considered to be good samples for investigating triggered star formation. In this paper we report on the investigation of the dust properties of the infrared bubble N4 around the H ii region G11.898+0.747, analyzing its interaction with its surroundings and star formation histories therein, with the aim of determining the possibility of star formation triggered by the expansion of the bubble. Using Herschel PACS and SPIRE images with a wide wavelength coverage, we reveal the dust properties over the entire bubble. Meanwhile, we are able to identify six dust clumps surrounding the bubble, with a mean size of 0.50 pc, temperature of about 22 K, mean column density of 1.7 × 10{sup 22} cm{sup −2}, mean volume density of about 4.4 × 10{sup 4} cm{sup −3}, and a mean mass of 320 M{sub ⊙}. In addition, from PAH emission seen at 8 μm, free–free emission detected at 20 cm, and a probability density function in special regions, we could identify clear signatures of the influence of the H ii region on the surroundings. There are hints of star formation, though further investigation is required to demonstrate that N4 is the triggering source.

  9. Double bubble with the big-bubble technique during deep anterior lamellar keratoplasty.

    Science.gov (United States)

    Wise, Stephanie; Dubord, Paul; Yeung, Sonia N

    2017-04-28

    To report a case of intraoperative double bubble that formed during big-bubble DALK surgery in a patient with corneal scarring secondary to herpetic stromal keratitis. Case report. A 22 year old woman presented with a large corneal scar, likely secondary to previous herpetic stromal keratitis. She underwent big-bubble DALK surgery for visual rehabilitation. Intraoperatively, a mixed bubble with persistent type 2 bubble postoperatively was noted. The second bubble resorbed with clearance of the graft and good visual outcome after 6 weeks. This case report describes the unusual development of a mixed bubble during big-bubble DALK surgery. This graft cleared with resolution of the second bubble postoperatively without further surgical intervention.

  10. TraumaTutor: Perceptions of a Smartphone Application as a Learning Resource for Trauma Management

    Directory of Open Access Journals (Sweden)

    James Wigley

    2013-01-01

    Full Text Available Aim. We investigated perceptions of a new smartphone application (app as a learning resource. Methods. We developed TraumaTutor, an iPhone app consisting of 150 questions and explanatory answers on trauma management. This was used by 20 hospital staff that either had a special interest in managing trauma or who were studying for relevant exams, such as ATLS. A subsequent questionnaire assessed users’ experience of smartphone applications and their perceptions of TraumaTutor. Results. Of those surveyed, 85% had a device capable of running app software, and 94% of them had used apps for medical education. Specific to TraumaTutor, 85% agreed that it was pitched at the right level, 95% felt that the explanations improved understanding of trauma management, and 100% found the app easy to use. In fact, on open questioning, the clear user interface and the quality of the educational material were seen as the major advantages of TraumaTutor, and 85% agreed that the app would be a useful learning resource. Conclusions. Smartphone applications are considered a valuable educational adjunct and are commonly used by our target audience. TraumaTutor shows overwhelming promise as a learning supplement due to its immediacy, accessibility, and relevance to those preparing for courses and managing trauma.

  11. Application of Defocusing Technique to Bubble Depth Measurement

    OpenAIRE

    Mugikura, Yuki

    2017-01-01

    The thesis presents a defocusing technique to extract bubble depth information. Typically, when a bubble is out of focus in an image, the bubble is ignored by applying a filter or thresholding. However, it is known that a bubble image becomes blurred as the bubble moves away from the focal plane. Then, this technique is applied to determine the bubble distance along the optical path based on the blurriness or intensity gradient information of the bubble. Using the image processing algorithm, ...

  12. Sexual assault trauma and trauma change.

    Science.gov (United States)

    Ruch, L O; Leon, J J

    1983-01-01

    An exploratory model of variables affecting level of sexual assault trauma at given times and change in trauma levels over time is developed and tested using a sample of female rape victims admitted to a treatment center over a two-year period. Based on a one-way analysis of variance and multiple classification analysis, the findings indicate that a previous rape best explains trauma change, while victim's demographics, social supports, and other prior life stress variables are important at specific time periods during the rape trauma syndrome. Implications of these results are discussed in terms of treatment-related issues.

  13. Cavitation inception from bubble nuclei

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2015-01-01

    . The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model......The tensile strength of ordinary water such as tap water or seawater is typically well below 1 bar. It is governed by cavitation nuclei in the water, not by the tensile strength of the water itself, which is extremely high. Different models of the nuclei have been suggested over the years......, and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid...

  14. Bubble entrapment through topological change

    KAUST Repository

    Thoroddsen, Sigurdur T.

    2010-05-03

    When a viscousdrop impacts onto a solid surface, it entraps a myriad of microbubbles at the interface between liquid and solid. We present direct high-speed video observations of this entrapment. For viscousdrops, the tip of the spreading lamella is separated from the surface and levitated on a cushion of air. We show that the primary mechanism for the bubble entrapment is contact between this precursor sheet of liquid with the solid and not air pulled directly through cusps in the contact line. The sheet makes contact with the solid surface,forming a wetted patch, which grows in size, but only entraps a bubble when it meets the advancing contact line. The leading front of this wet patch can also lead to the localized thinning and puncturing of the liquid film producing strong splashing of droplets.

  15. Presacral retroperitoneal hematoma after blunt trauma presents with rectal bleeding — A case report

    Directory of Open Access Journals (Sweden)

    Sanne Jensen Dich

    2016-01-01

    Conclusion: Rectal bleed after trauma, in a patient receiving anticoagulant treatment, should raise suspicion of a penetrating hematoma, and such patients should be managed at highly specialized facilities.

  16. Soap bubbles in paintings: Art and science

    Science.gov (United States)

    Behroozi, F.

    2008-12-01

    Soap bubbles became popular in 17th century paintings and prints primarily as a metaphor for the impermanence and fragility of life. The Dancing Couple (1663) by the Dutch painter Jan Steen is a good example which, among many other symbols, shows a young boy blowing soap bubbles. In the 18th century the French painter Jean-Simeon Chardin used soap bubbles not only as metaphor but also to express a sense of play and wonder. In his most famous painting, Soap Bubbles (1733/1734) a translucent and quavering soap bubble takes center stage. Chardin's contemporary Charles Van Loo painted his Soap Bubbles (1764) after seeing Chardin's work. In both paintings the soap bubbles have a hint of color and show two bright reflection spots. We discuss the physics involved and explain how keenly the painters have observed the interaction of light and soap bubbles. We show that the two reflection spots on the soap bubbles are images of the light source, one real and one virtual, formed by the curved surface of the bubble. The faint colors are due to thin film interference effects.

  17. Informational pathologies and interest bubbles

    DEFF Research Database (Denmark)

    Hendricks, Vincent Fella; Wiewiura, Joachim Schmidt

    2017-01-01

    This article contends that certain configurations of information networks facilitate specific cognitive states that are instrumental for decision and action on social media. Group-related knowledge and belief states—in particular common knowledge and pluralistic ignorance—may enable strong public...... signals. Indeed, some network configurations and attitude states foster informational pathologies that may fuel interest bubbles affecting agenda-setting and the generation of narratives in public spheres....

  18. BEBC Big European Bubble Chamber

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    A view of the dismantling of the magnet of BEBC, the 3.7 m European Bubble Chamber : iron magnetic shielding ; lower and upper parts of the vacuum enclosure of the magnet; turbo-molecular vacuum pumps for the "fish-eye" windows; the two superconducting coils; a handling platform; the two cryostats suspended from the bar of the travelling crane which has a 170 ton carrying capacity. The chamber proper, not dismantled, is inside the shielding.

  19. Bubble-induced cave collapse.

    Science.gov (United States)

    Girihagama, Lakshika; Nof, Doron; Hancock, Cathrine

    2015-01-01

    Conventional wisdom among cave divers is that submerged caves in aquifers, such as in Florida or the Yucatan, are unstable due to their ever-growing size from limestone dissolution in water. Cave divers occasionally noted partial cave collapses occurring while they were in the cave, attributing this to their unintentional (and frowned upon) physical contact with the cave walls or the aforementioned "natural" instability of the cave. Here, we suggest that these cave collapses do not necessarily result from cave instability or contacts with walls, but rather from divers bubbles rising to the ceiling and reducing the buoyancy acting on isolated ceiling rocks. Using familiar theories for the strength of flat and arched (un-cracked) beams, we first show that the flat ceiling of a submerged limestone cave can have a horizontal expanse of 63 meters. This is much broader than that of most submerged Florida caves (~ 10 m). Similarly, we show that an arched cave roof can have a still larger expanse of 240 meters, again implying that Florida caves are structurally stable. Using familiar bubble dynamics, fluid dynamics of bubble-induced flows, and accustomed diving practices, we show that a group of 1-3 divers submerged below a loosely connected ceiling rock will quickly trigger it to fall causing a "collapse". We then present a set of qualitative laboratory experiments illustrating such a collapse in a circular laboratory cave (i.e., a cave with a circular cross section), with concave and convex ceilings. In these experiments, a metal ball represented the rock (attached to the cave ceiling with a magnet), and the bubbles were produced using a syringe located at the cave floor.

  20. Decolonizing Trauma Studies Round-Table Discussion

    Directory of Open Access Journals (Sweden)

    Stef Craps

    2015-11-01

    Full Text Available This round-table, which featured literary critics Professor Stef Craps, Professor Bryan Cheyette and Dr. Alan Gibbs, was recorded as part of the “Decolonizing Trauma Studies” symposium organized by Dr. Sonya Andermahr and Dr. Larissa Allwork at The School of The Arts, The University of Northampton (15 May 2015. Convened a week after the University of Zaragoza’s “Memory Frictions” conference, where Cheyette, Gibbs, Andermahr and Allwork gave papers, the Northampton symposium and round-table was sponsored by The School of The Arts to coincide with Andermahr’s guest editorship of this special issue of Humanities. Craps, Cheyette and Gibbs addressed five questions during the round-table. Namely, does trauma studies suffer from a form of psychological universalism? Do you see any signs that trauma studies is becoming more decolonized? What are the challenges of a decolonized trauma studies for disciplinary thinking? How does a decolonized trauma studies relate to pedagogical ethics? Finally, where do you see the future of the field? While this edited transcript retains a certain informality of style, it offers a significant contribution to knowledge by capturing a unique exchange between three key thinkers in contemporary trauma studies, providing a timely analysis of the impact of postcolonial theory on trauma studies, the state of the field and its future possibilities. Issues addressed include the problematic scholarly tendency to universalize a western model of Post-Traumatic Stress Disorder (PTSD; the question of the centrality of the Holocaust in trauma studies and the implications of this for the study of atrocities globally; the vexed issues posed by the representation of perpetrators; as well as how the basic tenets of western cultural trauma theory, until recently so often characterized by a Caruth-inspired focus on belatedness and afterwardness, are being rethought, both in response to developments in the US and in answer to

  1. Bubble capture by a propeller

    Science.gov (United States)

    Caillé, François; Clanet, Christophe; Magnaudet, Jacques

    2006-08-01

    A small air bubble (radius a) is injected in water (kinematic viscosity nu) in the vicinity (distance r_0) of a propeller (radius r_p, angular frequency omega). We study experimentally and theoretically the conditions under which the bubble can be ‘captured’, i.e. deviated from its vertical trajectory (imposed by gravity g) and moved toward the centre of the propeller (r {=} 0). We show that the capture frequency omega_{scriptsizecapt} follows the relationship [omega_{hboxriptsizeit capt}=left(frac{2ga^2}{9betanu r_p f(hboxRe_b)}right)left(frac{r_0}{r_p}right)^2(1+\\cos\\varphi_0),] where beta is a dimensionless parameter characterizing the propeller, f(Re_b) is an empirical correction to Stokes' drag law which accounts for finite-Reynolds-number effects and pi/2-varphi_0 is the angle between the axis of the propeller and the line between the centre of the propeller and the point where the bubble is injected. This law is found to be valid as long as the distance d between the propeller and the water surface is larger than 3r_0. For smaller distances, the capture frequency increases; using an image technique, we show how the above expression is modified by the presence of the surface.

  2. Interaction of positive streamers in air with bubbles floating on liquid surfaces: conductive and dielectric bubbles

    Science.gov (United States)

    Babaeva, Natalia Yu; Naidis, George V.; Kushner, Mark J.

    2018-01-01

    The interaction of plasmas sustained in humid air with liquids produces reactive species in both the gas phase and liquid for applications ranging from medicine to agriculture. In several experiments, enhanced liquid reactivity has been produced when the liquid is a foam or a bubble coated liquid. To investigate the phenomena of streamers interacting with bubbles a two-dimensional computational investigation has been performed of streamer initiation and propagation on and inside hemispherical bubble-shells floating on a liquid surface. Following prior experiments, water and oil bubble-shells with an electrode located outside and inside the bubble were investigated. We found that positive air streamers interact differently with conductive water and dielectric oil bubbles. The streamer propagates along the external surface of a water bubble while not penetrating through the bubble due to screening of the electric field by the conducting shell. If the electrode is inserted inside the bubble, the path of the streamer depends on how deeply the electrode penetrates. For shallow penetration, the streamer propagates along the inner surface of the bubble. Due to the low conductivity of oil bubble-shells, the electric field from an external electrode penetrates into the interior of the bubble. The streamer can then be re-initiated inside the bubble.

  3. Variations in pediatric trauma transfer patterns in Northern California pediatric trauma centers (2001-2009).

    Science.gov (United States)

    Vogel, Lara D; Vongsachang, Hurnan; Pirrotta, Elizabeth; Holmes, James F; Holmes, James M; Sherck, John; Newton, Christopher; D'Souza, Peter; Spain, David A; Wang, N Ewen

    2014-09-01

    Due to the scarcity of specialized resources for pediatric trauma, "regionalization," or a system designed to get "the right child, to the right place, at the right time," is vital to quality pediatric trauma care. In Northern California, four pediatric trauma centers serve 3.9 million children within a geographically diverse area of 113,630 square miles. A significant proportion of children with trauma is initially triaged to nontrauma hospitals and may require subsequent transfer to a specialty center. Trauma transfer patterns to a pediatric trauma center may provide insight into regional primary triage practices. Transfers from hospitals in close proximity to pediatric trauma centers might suggest that some children could have avoided transfer with minimal additional transport time. While pediatric trauma centers are scarce and serve as regional resources, transfers from beyond the regular catchment area of a trauma center could be an indication of clinical need. The objective of this study was to gain an understanding of patterns of pediatric trauma transfer to all pediatric trauma centers within the region as a first step in assessing the efficacy and efficiency of trauma triage. The authors examined three groups of transfer patients: transfers from within the same county as the pediatric trauma center (near transfers), transfers from counties adjacent to the pediatric trauma center (catchment transfers), and transfers from more distant counties (far transfers). The hypothesis was that catchment transfers would form the bulk of transfers, near transfers would compose transfers, and far transfers would be younger and more severely injured than catchment transfers. This was a retrospective analysis of institutional trauma registry data of children pediatric trauma centers in Northern California from 2001 through 2009. Transfers were characterized by the location of the transfer hospital relative to the location of the pediatric trauma center. Characteristics

  4. Bernoulli Suction Effect on Soap Bubble Blowing?

    Science.gov (United States)

    Davidson, John; Ryu, Sangjin

    2015-11-01

    As a model system for thin-film bubble with two gas-liquid interfaces, we experimentally investigated the pinch-off of soap bubble blowing. Using the lab-built bubble blower and high-speed videography, we have found that the scaling law exponent of soap bubble pinch-off is 2/3, which is similar to that of soap film bridge. Because air flowed through the decreasing neck of soap film tube, we studied possible Bernoulli suction effect on soap bubble pinch-off by evaluating the Reynolds number of airflow. Image processing was utilized to calculate approximate volume of growing soap film tube and the volume flow rate of the airflow, and the Reynolds number was estimated to be 800-3200. This result suggests that soap bubbling may involve the Bernoulli suction effect.

  5. Single DNA denaturation and bubble dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Metzler, Ralf [Physics Department, Technical University of Munich, James Franck Strasse, 85747 Garching (Germany); Ambjoernsson, Tobias [Chemistry Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Hanke, Andreas [Department of Physics and Astronomy, University of Texas, 80 Fort Brown, Brownsville (United States); Fogedby, Hans C [Department of Physics and Astronomy, University of Arhus, Ny Munkegade, 8000 Arhus C (Denmark)], E-mail: metz@ph.tum.de

    2009-01-21

    While the Watson-Crick double-strand is the thermodynamically stable state of DNA in a wide range of temperature and salt conditions, even at physiological conditions local denaturation bubbles may open up spontaneously due to thermal activation. By raising the ambient temperature, titration, or by external forces in single molecule setups bubbles proliferate until full denaturation of the DNA occurs. Based on the Poland-Scheraga model we investigate both the equilibrium transition of DNA denaturation and the dynamics of the denaturation bubbles with respect to recent single DNA chain experiments for situations below, at, and above the denaturation transition. We also propose a new single molecule setup based on DNA constructs with two bubble zones to measure the bubble coalescence and extract the physical parameters relevant to DNA breathing. Finally we consider the interplay between denaturation bubbles and selectively single-stranded DNA binding proteins.

  6. Direct Numerical Simulation of the Lift Force in Bubbly Flows

    NARCIS (Netherlands)

    Dijkhuizen, W.; van Sint Annaland, M.; Kuipers, J.A.M.

    2008-01-01

    It is well-known that the lift force is responsible for the segregation of small and large bubbles encountered in bubbly flows through pipes and bubble columns: in the case of up flow small spherical bubbles move to the wall, while larger deformed bubbles move to the core region. Depending on the

  7. Military Sexual Trauma

    Science.gov (United States)

    ... ZIP code here Enter ZIP code here Military Sexual Trauma Overview Programs & Services Articles & Fact Sheets Other Resources ... local Veterans Benefits Administration Regional Office . Overview Military sexual trauma (MST) is the term that the Department of ...

  8. Bursting the bubble of melt inclusions

    Science.gov (United States)

    Lowenstern, Jacob B.

    2015-01-01

    Most silicate melt inclusions (MI) contain bubbles, whose significance has been alternately calculated, pondered, and ignored, but rarely if ever directly explored. Moore et al. (2015) analyze the bubbles, as well as their host glasses, and conclude that they often hold the preponderance of CO2 in the MI. Their findings entreat future researchers to account for the presence of bubbles in MI when calculating volatile budgets, saturation pressures, and eruptive flux.

  9. Cusped Bubbles Rising through Polyelectrolyte Solutions

    Science.gov (United States)

    Belmonte, Andrew; Sostarecz, Michael

    2000-11-01

    It is well known that a bubble rising in a polymer fluid can have a cusp-like tail. We report on an experimental study of bubbles rising through solutions of glycerol/water with the addition of the polymer xanthan gum, a polyelectrolyte which becomes more rigid as the free ion concentration is increased. The addition of salt also decreases the elasticity of the xanthan gum solutions, and we observe its effects on the velocity and shape of the cusped bubble.

  10. Detailed Jet Dynamics in a Collapsing Bubble

    Science.gov (United States)

    Supponen, Outi; Obreschkow, Danail; Kobel, Philippe; Farhat, Mohamed

    2015-12-01

    We present detailed visualizations of the micro-jet forming inside an aspherically collapsing cavitation bubble near a free surface. The high-quality visualizations of large and strongly deformed bubbles disclose so far unseen features of the dynamics inside the bubble, such as a mushroom-like flattened jet-tip, crown formation and micro-droplets. We also find that jetting near a free surface reduces the collapse time relative to the Rayleigh time.

  11. Asset Bubbles, Endogenous Growth, and Financial Frictions

    OpenAIRE

    Hirano, Tomohiro; Yanagawa, Noriyuki

    2016-01-01

    This paper analyzes the effects of bubbles in an infinitely-lived agent model of endogenous growth with financial frictions and heterogeneous agents. We provide a complete characterization on the relationship between financial frictions and the existence of bubbles. Our model predicts that if the degree of pledgeability is sufficiently high or sufficiently low, bubbles can not exist. They can only arise at an intermediate degree. This suggests that improving the financial market condition mig...

  12. Bubbles, Financial Crises, and Systemic Risk

    OpenAIRE

    Markus K. Brunnermeier; Martin Oehmke

    2012-01-01

    This chapter surveys the literature on bubbles, financial crises, and systemic risk. The first part of the chapter provides a brief historical account of bubbles and financial crisis. The second part of the chapter gives a structured overview of the literature on financial bubbles. The third part of the chapter discusses the literatures on financial crises and systemic risk, with particular emphasis on amplification and propagation mechanisms during financial crises, and the measurement of sy...

  13. Trauma during pregnancy

    Directory of Open Access Journals (Sweden)

    Siddareddigari Velayudha Reddy

    2012-01-01

    Full Text Available Trauma in pregnancy presents a unique challenge, because of the anatomical and physiological changes of pregnancy, and the assessment and treatment of pregnant patients differ accordingly. In this review article, the focus is on familiarizing the anesthesiologists with physiological changes of pregnancy, their effect on response to trauma, resuscitation, and anesthetic management of trauma patient during pregnancy.

  14. in penetrating abdominal trauma

    African Journals Online (AJOL)

    particularly in trauma surgery. The benefits of ERAS/ERPs are well established. They have shown faster physiological patient recovery, and reduced length of hospital stay without. Enhanced recovery after surgery (ERAS) in penetrating abdominal trauma: A prospective single-center pilot study. TRAUMA. M R Moydien, R ...

  15. Trauma resuscitation time.

    NARCIS (Netherlands)

    Olden, G.D.J. van; Vugt, A.B. van; Biert, J.; Goris, R.J.A.

    2003-01-01

    Documenting the timing and organisation of trauma resuscitation can be utilised to assess performance standards, and to ensure a high quality of trauma resuscitation procedures. Since there is no European literature available on trauma resuscitation time (TRT) in the emergency room, the aim of this

  16. Suppression of shocked-bubble expansion due to tissue confinement with application to shock-wave lithotripsy.

    Science.gov (United States)

    Freund, Jonathan B

    2008-05-01

    Estimates are made of the effect of tissue confinement on the response of small bubbles subjected to lithotriptor shock pressures. To do this the Rayleigh-Plesset equation, which governs the dynamics of spherical bubbles, is generalized to treat a bubble in a liquid region (blood), which is in turn encased within an elastic membrane (like a vessel's basement membrane), beyond which a Voigt viscoelastic material models the exterior tissue. Material properties are estimated from a range of measurements available for kidneys and similar soft tissues. Special attention is given to the constitutive modeling of the basement membranes because of their expected importance due to their proximity to the bubble and their toughness. It is found that the highest expected values for the elasticity of the membrane and surrounding tissue are insufficient to suppress bubble growth. The reduced confinement of a cylindrical vessel should not alter this conclusion. Tissue viscosities taken from ultrasound measurements suppress bubble growth somewhat, though not to a degree expected to resist injury. However, the higher reported viscosities measured by other means, which are arguably more relevant to the deformations caused by growing bubbles, do indeed significantly suppress bubble expansion.

  17. Stable bubble oscillations beyond Blake's critical threshold.

    Science.gov (United States)

    Hegedűs, Ferenc

    2014-04-01

    The equilibrium radius of a single spherical bubble containing both non-condensable gas and vapor is determined by the mechanical balance at the bubble interface. This expression highlights the fact that decreasing the ambient pressure below the so called Blake's critical threshold, the bubble has no equilibrium state at all. In the last decade many authors have tried to find evidence for the existence of stable bubble oscillation under harmonic forcing in this regime, that is, they have tried to stabilize the bubble motion applying ultrasonic radiation on the bubble. The available numerical results provide only partial proof for the existence as they are usually based on linearized or weakly nonlinear (higher order approximation) bubble models. Here, based on numerical techniques of the modern nonlinear and bifurcation theory, the existence of stable bubble motion has been proven without any restrictions in nonlinearities. Although the model, applied in this paper, is the rather simple Rayleigh-Plesset equation, the presented technique can be extended to more complex bubble models easily. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Improvised bubble continuous positive airway pressure (BCPAP ...

    African Journals Online (AJOL)

    Improvised bubble continuous positive airway pressure (BCPAP) device at the National Hospital Abuja gives immediate improvement in respiratory rate and oxygenation in neonates with respiratory distress.

  19. Trauma and trauma-related disorders for women on methadone: prevalence and treatment considerations.

    Science.gov (United States)

    Hien, D; Levin, F R

    1994-01-01

    There is a growing recognition of the strong association between psychoactive substance abuse and violence. Repeated exposure to violent trauma is particularly salient for women. Moreover, violent trauma may play a role in the etiologies of depression, substance abuse, and trauma-related disorders, such as posttraumatic stress disorder (PTSD). For the female methadone patient, an untreated trauma-related disorder can be a hidden factor that hinders treatment response and leads to treatment complications, such as depression, polysubstance abuse, or treatment drop out. This article reviews the prevalence of trauma and violence for women on methadone, comparing low-income, inner-city female drug abusers with males in methadone treatment on childhood and adulthood exposure to violent trauma and PTSD. Because women are in a minority in methadone maintenance treatment programs, standard treatment approaches have generally not focused on their particular issues and needs. Two alternative models are presented for group treatment of trauma and trauma-related disorders in female methadone patients; potential benefits of each in reducing symptomatology and improving interpersonal functioning are examined. Modification of standard approaches and the typical barriers to engagement in treatment for this special population are also addressed.

  20. Liquid jet formation through the interactions of a laser-induced bubble and a gas bubble

    Science.gov (United States)

    Han, Bing; Liu, Liu; Zhao, Xiong-Tao; Ni, Xiao-Wu

    2017-10-01

    The mechanisms of the liquid jet formation from the interaction of the laser-induced and gas bubble pair are investigated and compared with the jet formation from the interaction of the laser-induced anti-phase bubble pair. The strobe photography experimental method and numerical simulations are implemented to obtain the parameter space of the optimum liquid jet, i.e. highest speed and lowest diameter. It is found that due to the enhanced "catapult effect", which is induced by the protrusion of the first bubble into the second bubble and the flip back of the elongated part of the first bubble, the optimum liquid jet of the second bubble of the laser-induced anti-phase bubble pair compared to that of the laser-induced and gas bubble pair is 54 %, 65 % and 11 % faster in speed, and 4 %, 44 % and 64 % smaller in diameter, for the 500 μm, 50 μm and 5 μm sized bubbles, respectively. The optimum dimensionless distance for the optimum jet of the laser-induced and the gas bubble is around 0.7, when the maximum bubble radius increases from ˜ 5μm to ˜500 μm, which is different from the laser-induced anti-phase bubble pairs. Besides, the optimum jet of the laser-induced bubble appeared when the bubbles are equal sized, while that of the gas bubble is independent of the relative bubble size, i.e. the liquid jet of the gas bubble has higher robustness in real liquid jet assisted applications when the laser-induced bubble size varies. However, the jet of bubble 2 could maintain a high speed (20 m/s - 35 m/s) and a low diameter (˜5 % of the maximum bubble diameter) over a big range of the dimensionless distance (0.6 - 0.9) for both of the 50 μm and 500 μm sized laser-induced equal sized anti-phase bubble pairs.

  1. Local fixed pivot quadratue method of moment for bubble population balance equation including coalescence and breakage

    Science.gov (United States)

    Su, J. W.; Gu, Z. L.; Jiao, J. Y.; Xu, X. Y.

    2010-03-01

    Population balance equation as an essential tool to describe micro-behaviors and resulting bubble size distribution has received considerable attention in scientific and engineering fields. Numerical solution is the only choice in most cases due to its complexity. However, it is almost impossible for the existing numerical methods to predict both bubble size distribution and its moments exactly. In this work, a new numerical method basing on the idea of short time Fourier transformation, namely local fixed pivot quadrature method of moment, is proposed for bubble coalescence and breakage. A continuous summation of Dirac Delta function as trial functions in the local domain and monomials as the weighted functions to conserve the local moments were adopted. The moments and the bubble size distribution were constructed based on the moments in the local domain. Numerical tests including pure coalescence, pure breakage and coalescence and breakage combined processes showed that both the moments and bubble size distribution were predicted accurately. A special algorithm was used to solve the vandermonde linear system, with which the influence of the ill-conditioned feature of coefficient matrix on the numerical accuracy can be avoided. In theory any number of moments can be tracked with the new method. Moreover, with it one can solely track the bubble size distribution or the moments depending on the concrete application.

  2. Colorful Demos with a Long-Lasting Soap Bubble.

    Science.gov (United States)

    Behroozi, F.; Olson, D. W.

    1994-01-01

    Describes several demonstrations that feature interaction of light with soap bubbles. Includes directions about how to produce a long-lasting stationary soap bubble with an easily changeable size and describes the interaction of white light with the bubble. (DDR)

  3. Neural basis of economic bubble behavior.

    Science.gov (United States)

    Ogawa, A; Onozaki, T; Mizuno, T; Asamizuya, T; Ueno, K; Cheng, K; Iriki, A

    2014-04-18

    Throughout human history, economic bubbles have formed and burst. As a bubble grows, microeconomic behavior ceases to be constrained by realistic predictions. This contradicts the basic assumption of economics that agents have rational expectations. To examine the neural basis of behavior during bubbles, we performed functional magnetic resonance imaging while participants traded shares in a virtual stock exchange with two non-bubble stocks and one bubble stock. The price was largely deflected from the fair price in one of the non-bubble stocks, but not in the other. Their fair prices were specified. The price of the bubble stock showed a large increase and battering, as based on a real stock-market bust. The imaging results revealed modulation of the brain circuits that regulate trade behavior under different market conditions. The premotor cortex was activated only under a market condition in which the price was largely deflected from the fair price specified. During the bubble, brain regions associated with the cognitive processing that supports order decisions were identified. The asset preference that might bias the decision was associated with the ventrolateral prefrontal cortex and the dorsolateral prefrontal cortex (DLPFC). The activity of the inferior parietal lobule (IPL) was correlated with the score of future time perspective, which would bias the estimation of future price. These regions were deemed to form a distinctive network during the bubble. A functional connectivity analysis showed that the connectivity between the DLPFC and the IPL was predominant compared with other connectivities only during the bubble. These findings indicate that uncertain and unstable market conditions changed brain modes in traders. These brain mechanisms might lead to a loss of control caused by wishful thinking, and to microeconomic bubbles that expand, on the macroscopic scale, toward bust. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Trauma in pregnancy.

    Science.gov (United States)

    Mattox, Kenneth L; Goetzl, Laura

    2005-10-01

    The objective of this article was to review the existing standards of practice regarding trauma which occurs during pregnancy. The design of this study was to review the available data from the surgical and obstetrical literature regarding trauma during pregnancy. The design was also to incorporate the contemporary recommendations from the trauma resuscitation courses relating to trauma during pregnancy. Trauma occurs in 5% of pregnancies. A fetus is not considered to be viable until week 25. Motor vehicle accidents account for more than 50% of all trauma during pregnancy, with 82% of fetal deaths occurring during these automobile accidents. With life threatening trauma a 50% fetal loss rate exists. As anatomy, physiology, and even laboratory findings change during pregnancy, the clinician must consider both patients, the mother and fetus. Following blunt trauma abruption of the placenta is the more common cause of fetus loss. Anterior abdominal penetrating trauma almost never fails to injury the uterus and fetus in the last half of pregnancy. Preventive strategies exist in the areas of social violence, automobile restraints and use of alcohol and drugs by the mother. Perimortem caesarian section is rarely successful. Trauma during pregnancy is uncommon, but with increasing trauma severity leads to increased fetal loss. Preventive strategies exist and when admitted monitoring standards should be followed.

  5. Ultrasonography in trauma

    DEFF Research Database (Denmark)

    Weile, Jesper; Nielsen, Klaus; Primdahl, Stine C

    2017-01-01

    BACKGROUND: The Focused Assessment with Sonography in Trauma (FAST) protocol is considered beneficial in emergent evaluation of trauma patients with blunt or penetrating injury and has become integrated into the Advanced Trauma Life Support (ATLS) protocol. No guidelines exist as to the use...... of ultrasonography in trauma in Denmark. We aimed to determine the current use of ultrasonography for assessing trauma patients in Denmark. METHODS: We conducted a nation-wide cross-sectional investigation of ultrasonography usage in trauma care. The first phase consisted of an Internet-based investigation....... Twenty-one (95.5%) of the guidelines included and recommended FAST as part of trauma assessment. The recommended person to perform the examination was the radiologist in n = 11 (50.0%), the surgeon in n = 6 (27.3%), the anesthesiologist in n = 1 (4.5%), and unspecified in n = 3 (13.6%) facilities. FAST...

  6. Spherically symmetric conformal gravity and "gravitational bubbles"

    CERN Document Server

    Berezin, V A; Eroshenko, Yu N

    2016-01-01

    The general structure of the spherically symmetric solutions in the Weyl conformal gravity is described. The corresponding Bach equation are derived for the special type of metrics, which can be considered as the representative of the general class. The complete set of the pure vacuum solutions is found. It consists of two classes. The first one contains the solutions with constant two-dimensional curvature scalar of our specific metrics, and the representatives are the famous Robertson-Walker metrics. One of them we called the "gravitational bubbles", which is compact and with zero Weyl tensor. The second class is more general, with varying curvature scalar. We found its representative as the one-parameter family. It appears that it can be conformally covered by the thee-parameter Mannheim-Kazanas solution. We also investigated the general structure of the energy-momentum tensor in the spherical conformal gravity and constructed the vectorial equation that reveals clearly the same features of non-vacuum solu...

  7. Nurse-Led Trauma-Informed Correctional Care for Women.

    Science.gov (United States)

    Mollard, Elizabeth; Brage Hudson, Diane

    2016-07-01

    Incarcerated women are a vulnerable and unique population of special concern to nurses as they have high rates of mental illness. In this article, the authors discuss how trauma exposure contributes to mental illness in incarcerated women through abuse, socioeconomic factors, and the prison environment, how this trauma exposure manifests in the inmate survivor, and the related implications for practice. A history of trauma and victimization is related to complex mental health issues which affect the majority of justice-involved women. The correctional environment can exacerbate these issues. Nursing implications include discussion of the trauma-informed care model. The authors recommend a model of trauma-informed care named "the 4 Es" that can guide nurses in preparing a trauma-informed correctional environment and discuss the importance of nurse-led policy change in finding alternatives to incarceration for women with mental illness. © 2015 Wiley Periodicals, Inc.

  8. Intraoperative review of different bubble types formed during pneumodissection (big-bubble) deep anterior lamellar keratoplasty.

    Science.gov (United States)

    Goweida, Mohamed Bahgat Badawi

    2015-06-01

    To evaluate the preoperative factors and intraoperative complications of the 2 bubble types formed during big-bubble deep anterior lamellar keratoplasty (DALK). This is a retrospective review of medical records of a series of patients who underwent DALK using the big-bubble technique from September 2009 to March 2014. A total of 134 eyes were included in this study-89 eyes with advanced keratoconus, 35 eyes with post-microbial keratitis corneal scars, 8 eyes with stromal dystrophies, and 2 eyes with post-laser in situ keratomileusis ectasia. A type 1 bubble (white margin) was achieved in 56 eyes (41.8%), whereas a type 2 bubble (clear margin) was formed in 14 eyes (10.4%) and a mixed bubble was formed in 2 eyes (1.5%). Big-bubble formation failed in 62 (46.3%). All eyes with the type 1 bubble were completed as DALK; microperforation occurred in 4 eyes. Twelve of 14 eyes with the type 2 bubble were converted to penetrating keratoplasty because of large perforations. The type 2 bubble is more likely to form in elderly patients and those with deep corneal scars and thin corneas. Because of the high rate of conversion to penetrating keratoplasty, better surgical strategies may be needed to manage type 2 bubbles.

  9. Measurement of Bubble Size Distribution Based on Acoustic Propagation in Bubbly Medium

    Science.gov (United States)

    Wu, Xiongjun; Hsiao, Chao-Tsung; Choi, Jin-Keun; Chahine, Georges

    2013-03-01

    Acoustic properties are strongly affected by bubble size distribution in a bubbly medium. Measurement of the acoustic transmission becomes increasingly difficulty as the void fraction of the bubbly medium increases due to strong attenuation, while acoustic reflection can be measured more easily with increasing void fraction. The ABS ACOUSTIC BUBBLE SPECTROMETER®\\copyright, an instrument for bubble size measurement that is under development tries to take full advantage of the properties of acoustic propagation in bubbly media to extract bubble size distribution. Properties of both acoustic transmission and reflection in the bubbly medium from a range of short single-frequency bursts of acoustic waves at different frequencies are measured in an effort to deduce the bubble size distribution. With the combination of both acoustic transmission and reflection, assisted with validations from photography, the ABS ACOUSTIC BUBBLE SPECTROMETER®\\copyright has the potential to measure bubble size distributions in a wider void fraction range. This work was sponsored by Department of Energy SBIR program

  10. Bubble aspect ratio in dense bubbly flows: experimental studies in low Morton-number systems

    Science.gov (United States)

    Besagni, G.; Inzoli, F.; Ziegenhein, T.; Hessenkemper, H.; Lucas, D.

    2017-11-01

    Almost every modelling approach of bubbly flows includes assumptions concerning the bubble shape. Such assumptions are usually made based on single bubble experiments in quiescent flows, which is far away from the flow field observed in large-scale multiphase facilities. Considering low Morton-numbers and the highly deformable interface at medium and large Eötvös-numbers, the evaluation of the bubble shape in such systems under real flow conditions is highly desirable. In this study, we experimentally evaluate the bubble shape (in terms of aspect ratio), at low Morton-numbers, in different bubble column setups and a pipe flow setup under different operating conditions. The bubble shape in the bubble column experiments were obtained with cameras at Politecnico di Milano and Helmholtz-Zentrum Dresden Rossendorf (HZDR) whereas the shapes in the pipe flows were measured by the ultrafast electron beam X-ray tomography system (ROFEX) at HZDR. In the bubble column experiments almost the same shape is observed; conversely, the shape in the pipe flows distinctly depends on the flow conditions. In conclusion, in bubble columns the assumption of a constant shape regardless of the flow conditions is valid whereas in pipe flows the turbulence and shear rates can be strong enough to deform distinctly the bubbles.

  11. Bubble Movement on Inclined Hydrophobic Surfaces.

    Science.gov (United States)

    Kibar, Ali; Ozbay, Ridvan; Sarshar, Mohammad Amin; Kang, Yong Tae; Choi, Chang-Hwan

    2017-10-31

    The movement of a single air bubble on an inclined hydrophobic surface submerged in water, including both the upward- and downward-facing sides of the surface, was investigated. A planar Teflon sheet with an apparent contact angle of a sessile water droplet of 106° was used as a hydrophobic surface. The volume of a bubble and the inclination angle of a Teflon sheet varied in the ranges 5-40 μL and 0-45°, respectively. The effects of the bubble volume on the adhesion and dynamics of the bubble were studied experimentally on the facing-up and facing-down surfaces of the submerged hydrophobic Teflon sheet, respectively, and compared. The result shows that the sliding angle has an inverse relationship with the bubble volume for both the upward- and downward-facing surfaces. However, at the same given volume, the bubble on the downward-facing surface spreads over a larger area of the hydrophobic surface than the upward-facing surface due to the greater hydrostatic pressure acting on the bubble on the downward-facing surface. This makes the lateral adhesion force of the bubble greater and requires a larger inclination angle to result in sliding.

  12. The Minnaert Bubble: An Acoustic Approach

    Science.gov (United States)

    Devaud, Martin; Hocquet, Thierry; Bacri, Jean-Claude; Leroy, Valentin

    2008-01-01

    We propose an "ab initio" introduction to the well-known Minnaert pulsating bubble at graduate level. After a brief recall of the standard stuff, we begin with a detailed discussion of the radial movements of an air bubble in water. This discussion is managed from an acoustic point of view, and using the Lagrangian rather than the Eulerian…

  13. The life and death of film bubbles

    Science.gov (United States)

    Poulain, S.; Villermaux, E.; Bourouiba, L.

    2017-11-01

    Following its burst, the fragmentation of a large bubble (film bubble) at the air-water interface can release hundreds of micrometer-sized film-drops in the air we breathe. This mechanism of droplet formation is one of the most prominent sources of sea spray. Indoor or outdoor, pathogens from contaminated water are transported by these droplets and have also been linked to respiratory infection. The lifetime and thickness of bubbles govern the number and size of the droplets they produce. Despite these important implications, little is known about the factors influencing the life and death of surface film bubbles. In particular, the fundamental physical mechanisms linking bubble aging, thinning, and lifetime remain poorly understood. To address this gap, we present the results of an extensive investigation of the aging of film-drop-producing bubbles in various ambient air, water composition, and temperature conditions. We present and validate a generalized physical picture and model of bubble cap thickness evolution. The model and physical picture are linked to the lifetime of bubbles via a series of cap rupture mechanisms of increasing efficiency.

  14. Steady State Vapor Bubble in Pool Boiling.

    Science.gov (United States)

    Zou, An; Chanana, Ashish; Agrawal, Amit; Wayner, Peter C; Maroo, Shalabh C

    2016-02-03

    Boiling, a dynamic and multiscale process, has been studied for several decades; however, a comprehensive understanding of the process is still lacking. The bubble ebullition cycle, which occurs over millisecond time-span, makes it extremely challenging to study near-surface interfacial characteristics of a single bubble. Here, we create a steady-state vapor bubble that can remain stable for hours in a pool of sub-cooled water using a femtosecond laser source. The stability of the bubble allows us to measure the contact-angle and perform in-situ imaging of the contact-line region and the microlayer, on hydrophilic and hydrophobic surfaces and in both degassed and regular (with dissolved air) water. The early growth stage of vapor bubble in degassed water shows a completely wetted bubble base with the microlayer, and the bubble does not depart from the surface due to reduced liquid pressure in the microlayer. Using experimental data and numerical simulations, we obtain permissible range of maximum heat transfer coefficient possible in nucleate boiling and the width of the evaporating layer in the contact-line region. This technique of creating and measuring fundamental characteristics of a stable vapor bubble will facilitate rational design of nanostructures for boiling enhancement and advance thermal management in electronics.

  15. Measuring the surface tension of soap bubbles

    Science.gov (United States)

    Sorensen, Carl D.

    1992-01-01

    The objectives are for students to gain an understanding of surface tension, to see that pressure inside a small bubble is larger than that inside a large bubble. These concepts can be used to explain the behavior of liquid foams as well as precipitate coarsening and grain growth. Equipment, supplies, and procedures are explained.

  16. Microfluidics with ultrasound-driven bubbles

    NARCIS (Netherlands)

    Marmottant, P.; Marmottant, P.G.M.; Raven, J.P.; Gardeniers, Johannes G.E.; Bomer, Johan G.; Hilgenfeldt, Sascha; Hilgenfeldt, S.

    2006-01-01

    Microstreaming from oscillating bubbles is known to induce vigorous vortex flow. Here we show how to harness the power of bubble streaming in an experiment to achieve directed transport flow of high velocity, allowing design and manufacture of microfluidic MEMS devices. By combining oscillating

  17. Videotaping the Lifespan of a Soap Bubble.

    Science.gov (United States)

    Ramme, Goran

    1995-01-01

    Describes how the use of a videotape to record the history of a soap bubble allows a study of many interesting events in considerable detail including interference fringes, convection and turbulence patterns on the surface, formation of black film, and the ultimate explosion of the bubble. (JRH)

  18. The Interaction of Two Underwater Explosion Bubbles

    Science.gov (United States)

    Milligan, Charles; Duncan, James

    1996-11-01

    The interaction between two growing and collapsing underwater explosion bubbles is studied experimentally and numerically. In the experiments, the bubbles are generated by detonating small Lead Azide explosive charges submerged in a transparent water tank, and the resulting interactions are photographed using a high-speed camera. The parametric studies include simultaneous detonation of two charges of different sizes, and detonation of identically sized charges at staggered times. When the time delay between detonations is significant, the collapsing first bubble forms a jet directed away from the expanding second bubble and then re-expands nonspherically. During the re-expansion of the first bubble, a micro-jet forms in the second bubble. Eventually this micro-jet pierces the side of the second bubble farthest from the first and vortex rings are formed. Numerical simulations of the interaction phenomena are achieved using a boundary element method. By partitioning the system into computational sub-domains it is possible to replicate many relevant physical details including jet formation, fluid-fluid impact, and bubble re-expansion after complete jet penetration. The numerical results are in qualitative agreement with the experimental findings.

  19. Interaction of cavitation bubbles on a wall

    NARCIS (Netherlands)

    Bremond, Nicolas; Bremond, N.P.; Arora, M.; Dammer, S.M.; Lohse, Detlef

    2006-01-01

    We report experimental and numerical investigations on the dynamics of the cavitation of bubbles on a solid surface and the interaction between them with the help of controlled cavitation nuclei: hemispherical bubbles are nucleated from hydrophobic microcavities that act as gas traps when the

  20. Clustering and Lagrangian Statistics of Bubbles

    NARCIS (Netherlands)

    Martinez Mercado, J.

    2011-01-01

    Due to their relevance and occurrence in both natural phenomena and in industrial applications, the study and understanding of bubbly flows is currently an important topic for fluid dynamicists. Bubble columns are commonly used in bio- and petrochemical industries to enhance mixing, mass and heat

  1. The charged bubble oscillator: Dynamics and thresholds

    Indian Academy of Sciences (India)

    Technology-Bangalore (IIIT-B), 26/C Electronics City, Hosur Road, Bengaluru 560 100, India. 2School of Natural Sciences & Engineering, .... liquid, the difference in pressure causes expansion and rapid collapse of the bubble, followed ... of the dimensions of the bubble, we define an expansion- compression ratio that we ...

  2. The use of microholography in bubble chambers

    CERN Document Server

    Royer, H

    1981-01-01

    In-line holography has been used for the first time in a bubble chamber for the account of the CERN (Geneva, CH). The holograms were recorded with the help of a single-mode pulse laser. Bubble tracks of 25 microns in diameter have been reconstructed with a resolution of 2 microns. (12 refs).

  3. Laminar separation bubbles: Dynamics and control

    Indian Academy of Sciences (India)

    it thus are essential prerequisites for efficient design of these aerodynamic devices. Gaster. (1967) was the first to systematically explore the stability characteristics associated with the transition taking place in separation bubble. Many recent studies have been directed towards exploring the dynamics of separation bubbles ...

  4. Laminar separation bubbles: Dynamics and control

    Indian Academy of Sciences (India)

    This work is an experimental investigation of the dynamics and control of the laminar separation bubbles which are typically present on the suction surface of an aerofoil at a large angle of attack. A separation bubble is produced on the upper surface of a flat plate by appropriately contouring the top wall of the wind tunnel.

  5. Cavitation inception from bubble nuclei

    Science.gov (United States)

    Mørch, K. A.

    2015-01-01

    The tensile strength of ordinary water such as tap water or seawater is typically well below 1 bar. It is governed by cavitation nuclei in the water, not by the tensile strength of the water itself, which is extremely high. Different models of the nuclei have been suggested over the years, and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid. The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure–time history of the water. A recent model and associated experiments throw new light on the effects of transient pressures on the tensile strength of water, which may be notably reduced or increased by such pressure changes. PMID:26442138

  6. Gas Bubble Disease Monitoring and Research of Juvenile Salmonids : Annual Report 1996.

    Energy Technology Data Exchange (ETDEWEB)

    Maule, Alec G.; Beeman, John W.; Hans, Karen M.; Mesa, M.G.; Haner, P.; Warren, J.J. [Geological Survey, Cook, WA (United States). Columbia River Research Lab.

    1997-10-01

    This document describes the project activities 1996--1997 contract year. This report is composed of three chapters which contain data and analyses of the three main elements of the project: field research to determine the vertical distribution of migrating juvenile salmonids, monitoring of juvenile migrants at dams on the Snake and Columbia rivers, and laboratory experiments to describe the progression of gas bubble disease signs leading to mortality. The major findings described in this report are: A miniature pressure-sensitive radio transmitter was found to be accurate and precise and, after compensation for water temperature, can be used to determine the depth of tagged-fish to within 0.32 m of the true depth (Chapter 1). Preliminary data from very few fish suggest that depth protects migrating juvenile steelhead from total dissolved gas supersaturation (Chapter 1). As in 1995, few fish had any signs of gas bubble disease, but it appeared that prevalence and severity increased as fish migrated downstream and in response to changing gas supersaturation (Chapter 2). It appeared to gas bubble disease was not a threat to migrating juvenile salmonids when total dissolved gas supersaturation was < 120% (Chapter 2). Laboratory studies suggest that external examinations are appropriate for determining the severity of gas bubble disease in juvenile salmonids (Chapter 3). The authors developed a new method for examining gill arches for intravascular bubbles by clamping the ventral aorta to reduce bleeding when arches were removed (Chapter 3). Despite an outbreak of bacterial kidney disease in the experimental fish, the data indicate that gas bubble disease is a progressive trauma that can be monitored (Chapter 3).

  7. Galactic Teamwork Makes Distant Bubbles

    Science.gov (United States)

    Kohler, Susanna

    2016-03-01

    During the period of reionization that followed the dark ages of our universe, hydrogen was transformed from a neutral state, which is opaque to radiation, to an ionized one, which is transparent to radiation. But what generated the initial ionizing radiation? The recent discovery of multiple distant galaxies offers evidence for how this process occurred.Two Distant GalaxiesWe believe reionization occurred somewhere between a redshift of z = 6 and 7, because Ly-emitting galaxies drop out at roughly this redshift. Beyond this distance, were generally unable to see the light from these galaxies, because the universe is no longer transparent to their emission. This is not always the case, however: if a bubble of ionized gas exists around a distant galaxy, the radiation can escape, allowing us to see the galaxy.This is true of two recently-discovered Ly-emitting galaxies, confirmed to be at a redshift of z~7 and located near one another in a region known as the Bremer Deep Field. The fact that were able to see the radiation from these galaxies means that they are in an ionized HII region presumably one of the earlier regions to have become reionized in the universe.But on their own, neither of these galaxies is capable of generating an ionized bubble large enough for their light to escape. So what ionized the region around them, and what does this mean for our understanding of how reionization occurred in the universe?A Little Help From FriendsLocation in different filters of the objects in the Hubble Bremer Deep Field catalog. The z~7 selection region is outlined by the grey box. BDF-521 and BDF-3299 were the two originally discovered galaxies; the remaining red markers indicate the additional six galaxies discovered in the same region. [Castellano et al. 2016]A team of scientists led by Marco Castellano (Rome Observatory, INAF) investigated the possibility that there are other, faint galaxies near these two that have helped to ionize the region. Performing a survey

  8. Constraining hadronic models of the Fermi bubbles

    Science.gov (United States)

    Razzaque, Soebur

    2018-01-01

    The origin of sub-TeV gamma rays detected by Fermi-LAT from the Fermi bubbles at the Galactic center is unknown. In a hadronic model, acceleration of protons and/or nuclei and their subsequent interactions with gas in the bubble volume can produce observed gamma ray. Such interactions naturally produce high-energy neutrinos, and detection of those can discriminate between a hadronic and a leptonic origin of gamma rays. Additional constraints on the Fermi bubbles gamma-ray flux in the PeV range from recent HAWC observations restrict hadronic model parameters, which in turn disfavor Fermi bubbles as the origin of a large fraction of neutrino events detected by IceCube along the bubble directions. We revisit our hadronic model and discuss future constraints on parameters from observations in very high-energy gamma rays by CTA and in neutrinos.

  9. Oscillation of large air bubble cloud

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Y.Y.; Kim, H.Y.; Park, J.K. [Korea Atomic Energy Research Inst., Daejeon (Korea, Republic of)

    2001-07-01

    The behavior of a large air bubble cloud, which is generated by the air discharged from a perforated sparger, is analyzed by solving Rayleigh-Plesset equation, energy equations and energy balance equation. The equations are solved by Runge-Kutta integration and MacCormack finite difference method. Initial conditions such as driving pressure, air volume, and void fraction strongly affect the bubble pressure amplitude and oscillation frequency. The pool temperature has a strong effect on the oscillation frequency and a negligible effect on the pressure amplitude. The polytropic constant during the compression and expansion processes of individual bubbles ranges from 1.0 to 1.4, which may be attributed to the fact that small bubbles oscillated in frequencies different from their resonance. The temperature of the bubble cloud rapidly approaches the ambient temperature, as is expected from the polytropic constants being between 1.0 and 1.4. (authors)

  10. Bubble mobility in mud and magmatic volcanoes

    Science.gov (United States)

    Tran, Aaron; Rudolph, Maxwell L.; Manga, Michael

    2015-03-01

    The rheology of particle-laden fluids with a yield stress, such as mud or crystal-rich magmas, controls the mobility of bubbles, both the size needed to overcome the yield stress and their rise speed. We experimentally measured the velocities of bubbles and rigid spheres in mud sampled from the Davis-Schrimpf mud volcanoes adjacent to the Salton Sea, Southern California. Combined with previous measurements in the polymer gel Carbopol, we obtained an empirical model for the drag coefficient and bounded the conditions under which bubbles overcome the yield stress. Yield stresses typical of mud and basaltic magmas with sub-mm particles can immobilize millimeter to centimeter sized bubbles. At Stromboli volcano, Italy, a vertical yield stress gradient in the shallow conduit may immobilize bubbles with diameter ≲ 1 cm and hinder slug coalescence.

  11. Mesoporous hollow spheres from soap bubbling.

    Science.gov (United States)

    Yu, Xianglin; Liang, Fuxin; Liu, Jiguang; Lu, Yunfeng; Yang, Zhenzhong

    2012-02-01

    The smaller and more stable bubbles can be generated from the large parent bubbles by rupture. In the presence of a bubble blowing agent, hollow spheres can be prepared by bubbling a silica sol. Herein, the trapped gas inside the bubble acts as a template. When the porogen, i.e., other surfactant, is introduced, a mesostructured shell forms by the co-assembly with the silica sol during sol-gel process. Morphological evolution emphasizes the prerequisite of an intermediate interior gas flow rate and high exterior gas flow rate for hollow spheres. The method is valid for many compositions from inorganic, polymer to their composites. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Primordial black hole formation by vacuum bubbles

    Science.gov (United States)

    Deng, Heling; Vilenkin, Alexander

    2017-12-01

    Vacuum bubbles may nucleate during the inflationary epoch and expand, reaching relativistic speeds. After inflation ends, the bubbles are quickly slowed down, transferring their momentum to a shock wave that propagates outwards in the radiation background. The ultimate fate of the bubble depends on its size. Bubbles smaller than certain critical size collapse to ordinary black holes, while in the supercritical case the bubble interior inflates, forming a baby universe, which is connected to the exterior region by a wormhole. The wormhole then closes up, turning into two black holes at its two mouths. We use numerical simulations to find the masses of black holes formed in this scenario, both in subcritical and supercritical regime. The resulting mass spectrum is extremely broad, ranging over many orders of magnitude. For some parameter values, these black holes can serve as seeds for supermassive black holes and may account for LIGO observations.

  13. Interacting bubble clouds and their sonochemical production

    CERN Document Server

    Stricker, Laura; Rivas, David Fernandez; Lohse, Detlef

    2013-01-01

    Acoustically driven air pockets trapped in artificial crevices on a sur- face can emit bubbles which organize in (interacting) bubble clusters. With increasing driving power Fernandez Rivas et al. [Angew. Chem. Int. Ed., 2010] observed three different behaviors: clusters close to the very pits out of which they had been created, clusters pointing toward each other, and merging clusters. The latter behavior is highly undesired for technological purposes as it is associated with a reduction of the radical production and an enhancement of the erosion of the reactor walls. The dependence on the control parameters such as the distance of the pits and the conditions for cluster-merging are examined. The underlying mechanism, governed by the secondary Bjerknes forces, turns out to be strongly influenced by the nonlinearity of the bubble oscillations and not directly by the number of nucleated bubbles. The Bjerknes forces are found to dampen the bubble oscillations, thus reducing the radical production. Therefore, th...

  14. Bubble streams rising beneath an inclined surface

    Science.gov (United States)

    Bird, James; Brasz, Frederik; Kim, Dayoung; Menesses, Mark; Belden, Jesse

    2017-11-01

    Bubbles released beneath a submerged inclined surface can tumble along the wall as they rise, dragging the surrounding fluid with them. This effect has recently regained attention as a method to mitigate biofouling in marine environment, such as a ship hull. It appears that the efficacy of this approach may be related to the velocity of the rising bubbles and the extent that they spread laterally as they rise. Yet, it is unclear how bubble stream rise velocity and lateral migration depend on bubble size, flow rate, and inclination angle. Here we perform systematic experiments to quantify these relationships for both individual bubble trajectories and ensemble average statistics. Research supported by the Office of Naval Research under Grant Number award N00014-16-1-3000.

  15. Gas bubble dynamics in soft materials.

    Science.gov (United States)

    Solano-Altamirano, J M; Malcolm, John D; Goldman, Saul

    2015-01-07

    Epstein and Plesset's seminal work on the rate of gas bubble dissolution and growth in a simple liquid is generalized to render it applicable to a gas bubble embedded in a soft elastic solid. Both the underlying diffusion equation and the expression for the gas bubble pressure were modified to allow for the non-zero shear modulus of the medium. The extension of the diffusion equation results in a trivial shift (by an additive constant) in the value of the diffusion coefficient, and does not change the form of the rate equations. But the use of a generalized Young-Laplace equation for the bubble pressure resulted in significant differences on the dynamics of bubble dissolution and growth, relative to an inviscid liquid medium. Depending on whether the salient parameters (solute concentration, initial bubble radius, surface tension, and shear modulus) lead to bubble growth or dissolution, the effect of allowing for a non-zero shear modulus in the generalized Young-Laplace equation is to speed up the rate of bubble growth, or to reduce the rate of bubble dissolution, respectively. The relation to previous work on visco-elastic materials is discussed, as is the connection of this work to the problem of Decompression Sickness (specifically, "the bends"). Examples of tissues to which our expressions can be applied are provided. Also, a new phenomenon is predicted whereby, for some parameter values, a bubble can be metastable and persist for long times, or it may grow, when embedded in a homogeneous under-saturated soft elastic medium.

  16. Urogenital trauma: imaging upper GU trauma

    Energy Technology Data Exchange (ETDEWEB)

    Goldman, Stanford M. E-mail: Stanford.M.Goldman@uth.tmc.edu; Sandler, Carl M

    2004-04-01

    Objectives: This article will define the current controversies and concepts in the classification, clinical presentation, imaging approaches and management of upper urinary tract trauma. Materials and methods, results: This review will include the experience of the authors in the field of renal trauma over a 32-year period. Current thinking accepts the view that significant renal trauma is generally present when there is gross hematuria, signs of shock, or other clinical signs of severe injury. In most patients, suspected renal injury will be evaluated as a part of the overall assessment of the patient for suspected intraperitoneal injury. The authors will stress some exceptions to the rule. Conclusions: Most trauma experts now advocate conservative management, unless the patient is unstable or a renal vascular thrombosis or avulsion is suspected. Similarly, penetrating trauma to the kidney in and of itself no longer requires mandatory surgery. In the United States, computed tomography (CT), especially spiral CT, is considered the best diagnostic study, if available. Intravenous pyelography (IVP) is adequate if this is the only imaging modality available and if no concomitant injuries to the abdominal structure are suspected. Ultrasound, although strongly advocated in some countries, can lead to some significant false negatives. The diagnosis and management of unusual problems such as the traumatic AV fistula, the patient with an absent kidney or injury to the congenitally abnormal kidney, the serendipitous renal tumor in a patient with trauma, or serious bleeding after an apparent minor injury (i.e., spontaneous hemorrhage) are also reviewed in this article.

  17. Cellular High-Energy Cavitation Trauma - Description of a Novel In Vitro Trauma Model in Three Different Cell Types.

    Science.gov (United States)

    Cao, Yuli; Risling, Mårten; Malm, Elisabeth; Sondén, Anders; Bolling, Magnus Frödin; Sköld, Mattias K

    2016-01-01

    The mechanisms involved in traumatic brain injury have yet to be fully characterized. One mechanism that, especially in high-energy trauma, could be of importance is cavitation. Cavitation can be described as a process of vaporization, bubble generation, and bubble implosion as a result of a decrease and subsequent increase in pressure. Cavitation as an injury mechanism is difficult to visualize and model due to its short duration and limited spatial distribution. One strategy to analyze the cellular response of cavitation is to employ suitable in vitro models. The flyer-plate model is an in vitro high-energy trauma model that includes cavitation as a trauma mechanism. A copper fragment is accelerated by means of a laser, hits the bottom of a cell culture well causing cavitation, and shock waves inside the well and cell medium. We have found the flyer-plate model to be efficient, reproducible, and easy to control. In this study, we have used the model to analyze the cellular response to microcavitation in SH-SY5Y neuroblastoma, Caco-2, and C6 glioma cell lines. Mitotic activity in neuroblastoma and glioma was investigated with BrdU staining, and cell numbers were calculated using automated time-lapse imaging. We found variations between cell types and between different zones surrounding the lesion with these methods. It was also shown that the injured cell cultures released S-100B in a dose-dependent manner. Using gene expression microarray, a number of gene families of potential interest were found to be strongly, but differently regulated in neuroblastoma and glioma at 24 h post trauma. The data from the gene expression arrays may be used to identify new candidates for biomarkers in cavitation trauma. We conclude that our model is useful for studies of trauma in vitro and that it could be applied in future treatment studies.

  18. Cellular High-Energy Cavitation Trauma – Description of a Novel In Vitro Trauma Model in Three Different Cell Types

    Science.gov (United States)

    Cao, Yuli; Risling, Mårten; Malm, Elisabeth; Sondén, Anders; Bolling, Magnus Frödin; Sköld, Mattias K.

    2016-01-01

    The mechanisms involved in traumatic brain injury have yet to be fully characterized. One mechanism that, especially in high-energy trauma, could be of importance is cavitation. Cavitation can be described as a process of vaporization, bubble generation, and bubble implosion as a result of a decrease and subsequent increase in pressure. Cavitation as an injury mechanism is difficult to visualize and model due to its short duration and limited spatial distribution. One strategy to analyze the cellular response of cavitation is to employ suitable in vitro models. The flyer-plate model is an in vitro high-energy trauma model that includes cavitation as a trauma mechanism. A copper fragment is accelerated by means of a laser, hits the bottom of a cell culture well causing cavitation, and shock waves inside the well and cell medium. We have found the flyer-plate model to be efficient, reproducible, and easy to control. In this study, we have used the model to analyze the cellular response to microcavitation in SH-SY5Y neuroblastoma, Caco-2, and C6 glioma cell lines. Mitotic activity in neuroblastoma and glioma was investigated with BrdU staining, and cell numbers were calculated using automated time-lapse imaging. We found variations between cell types and between different zones surrounding the lesion with these methods. It was also shown that the injured cell cultures released S-100B in a dose-dependent manner. Using gene expression microarray, a number of gene families of potential interest were found to be strongly, but differently regulated in neuroblastoma and glioma at 24 h post trauma. The data from the gene expression arrays may be used to identify new candidates for biomarkers in cavitation trauma. We conclude that our model is useful for studies of trauma in vitro and that it could be applied in future treatment studies. PMID:26869990

  19. Cellular High-energy Cavitation Trauma - description of a novel in vitro trauma model in three different cell types.

    Directory of Open Access Journals (Sweden)

    Yuli eCao

    2016-02-01

    Full Text Available The mechanisms involved in traumatic brain injury (TBI have yet to be fully characterized. One mechanism that, especially in high energy trauma, could be of importance is cavitation. Cavitation can be described as a process of vaporization, bubble generation and bubble implosion as a result of a decrease and subsequent increase in pressure. Cavitation as an injury mechanism is difficult to visualize and model due to its short duration and limited spatial distribution. One strategy to analyze the cellular response of cavitation is to employ suitable in vitro models. The flyer plate is an in vitro high energy trauma model that includes cavitation as a trauma mechanism. A copper fragment is accelerated by means of a laser, hits the bottom of a cell culture well causing cavitation and shock waves inside the well and cell medium. We have found the flyer plate model to be efficient, reproducible and easy to control. In this study we have used the model to analyze the cellular response to microcavitation in SH-SY5Y neuroblastoma, Caco-2, and C6 glioma cell lines. Mitotic activity in neuroblastoma and glioma was investigated with BrdU staining, and cell numbers were calculated using automated time-lapse imaging. We found variations between cell types and between different zones surrounding the lesion with these methods. It was also shown that the injured cell cultures released S-100B in a dose dependent manner. Using gene expression microarray a number of gene families of potential interest were found to be strongly, but differently regulated in neuroblastoma and glioma at 24 hr post trauma. The data from the gene expression arrays may be used to identify new candidates for biomarkers in cavitation trauma. We conclude that our model is useful for studies of trauma in vitro and that it could be applied in future treatment studies.

  20. Observation of Microhollows Produced by Bubble Cloud Cavitation

    Science.gov (United States)

    Yamakoshi, Yoshiki; Miwa, Takashi

    2012-07-01

    When an ultrasonic wave with sound pressure less than the threshold level of bubble destruction irradiates microbubbles, the microbubbles aggregate by an acoustic radiation force and form bubble clouds. The cavitation of bubble clouds produces a large number of microhollows (microdips) on the flow channel wall. In this study, microhollow production by bubble cloud cavitation is evaluated using a blood vessel phantom made of N-isopropylacrylamide (NIPA) gel. Microbubble dynamics in bubble cloud cavitation is observed by a microscope with a short pulse light emitted diode (LED) light source. Microhollows produced on the flow channel wall are evaluated by a confocal laser microscope with a water immersion objective. It is observed that a mass of low-density bubbles (bubble mist) is formed by bubble cloud cavitation. The spatial correlation between the bubble mist and the microhollows shows the importance of the bubble mist in microhollow production by bubble cloud cavitation.

  1. Trauma Symptoms in Abused Children

    Directory of Open Access Journals (Sweden)

    Parvaneh Mohammadkhani

    2003-07-01

    Full Text Available Objective: There are many traumatic events (including natural disasters, physical, psychological and sexual abuse that may befall children and there is clear evidence that such experiences can produce a plethora of negative psychological effects. Children’s exposure to such traumas has been associated with a wide variety of negative mental health outcomes, including anxiety and depression, post-traumatic stress and dissociation and anger and aggression. It seems that the impacts of traumatic events are significantly related to type and intensity of trauma. Materials & Method: Through a systematized clustral sampling 3042 male and female students from junior high school who were participated in a survey study for investigating point prevalence of child abuse, completed Trauma Symptoms Checklist for Children-Alternate Version (TSCC-A and Child Abuse Self-report Scale (CASRS. After recognition of abused children, they were compared based on trauma symptoms. TSCC-A is a self-report measure of post-traumatic distress and related psychological symptomatology in male and female children aged 8-16 years. It is useful in the evaluation of children who have experienced traumatic events, including physical and sexual assault, victimization by peers, major losses, the witnessing of violence done to others and natural disasters. TSCC-A makes no reference to sexual issues. CASRS is a self-report scale to assess child abuse and neglect with 38 items and four subscales (psychological abuse, neglect, physical and sexual abuse. Results: Considering the type of traumatic experiences, the results showed that abused children significantly received higher scores in scales and subscales of TSCC-A than nonabused group. They specially reported more symptoms (depression, anxiety, post-traumatic stress, anger and dissociation comparing normal children. Conclusion: It is concluded that the type and rate of traumatic event is related to intensity of symptomatology.

  2. Dental Trauma Guide

    DEFF Research Database (Denmark)

    Andreasen, Jens Ove; Lauridsen, Eva; Gerds, Thomas Alexander

    2012-01-01

    Diagnosis and treatment for traumatic dental injuries are very complex owing to the multiple trauma entities represented by six luxation types and nine fracture types affecting both the primary and the permanent dentition. When it is further considered that fracture and luxation injuries are often...... combined, the result is that more than 100 trauma scenarios exist, when the two dentitions are combined. Each of these trauma scenarios has a specific treatment demand and prospect for healing. With such a complexity in diagnosis and treatment, it is obvious that even experienced practitioners may have...... problems in selecting proper treatment for some of these trauma types. To remedy this situation, an Internet-based knowledge base consisting of 4000 dental trauma cases with long-term follow up is now available to the public and the professions on the Internet using the address http://www.DentalTrauma...

  3. Management of duodenal trauma

    Directory of Open Access Journals (Sweden)

    CHEN Guo-qing

    2011-02-01

    Full Text Available 【Abstract】Duodenal trauma is uncommon but nowadays seen more and more frequently due to the increased automobile accidents and violent events. The management of duodenal trauma can be complicated, especially when massive injury to the pancreatic-duodenal-biliary complex occurs simultaneously. Even the patients receive surgeries in time, multiple postoperative complications and high mortality are common. To know and manage duodenal trauma better, we searched the recent related literature in PubMed by the keywords of duodenal trauma, therapy, diagnosis and abdomen. It shows that because the diagnosis and management are complicated and the mortality is high, duodenal trauma should be treated in time and tactfully. And application of new technology can help improve the management. In this review, we discussed the incidence, diagnosis, management, and complications as well as mortality of duodenal trauma. Key words: Duodenum; Wounds and injuries; Diagnosis; Therapeutics

  4. Nonlinear ultrasonic waves in bubbly liquids with nonhomogeneous bubble distribution: Numerical experiments.

    Science.gov (United States)

    Vanhille, Christian; Campos-Pozuelo, Cleofé

    2009-06-01

    This paper deals with the nonlinear propagation of ultrasonic waves in mixtures of air bubbles in water, but for which the bubble distribution is nonhomogeneous. The problem is modelled by means of a set of differential equations which describes the coupling of the acoustic field and bubbles vibration, and solved in the time domain via the use and adaptation of the SNOW-BL code. The attenuation and nonlinear effects are assumed to be due to the bubbles exclusively. The nonhomogeneity of the bubble distribution is introduced by the presence of bubble layers (or clouds) which can act as acoustic screens, and alters the behaviour of the ultrasonic waves. The effect of the spatial distribution of bubbles on the nonlinearity of the acoustic field is analyzed. Depending on the bubble density, dimension, shape, and position of the layers, its effects on the acoustic field change. Effects such as shielding and resonance of the bubbly layers are especially studied. The numerical experiments are carried out in two configurations: linear and nonlinear, i.e. for low and high excitation pressure amplitude, respectively, and the features of the phenomenon are compared. The parameters of the medium are chosen such as to reproduce air bubbly water involved in the stable cavitation process.

  5. Effect of bubble's arrangement on the viscous torque in bubbly Taylor-Couette flow

    Science.gov (United States)

    Fokoua, G. Ndongo; Gabillet, C.; Aubert, A.; Colin, C.

    2015-03-01

    An experimental investigation of the interactions between bubbles, coherent motion, and viscous drag in a Taylor-Couette flow with the outer cylinder at rest is presented. The cylinder radii ratio η is 0.91. Bubbles are injected inside the gap through a needle at the bottom of the apparatus. Different bubbles sizes are investigated (ratio between the bubble diameter and the gap width ranges from 0.05 to 0.125) for very small void fraction (α ≤ 0.23%). Different flow regimes are studied corresponding to Reynolds number Re based on the gap width and velocity of the inner cylinder, ranging from 6 × 102 to 2 × 104. Regarding these Re values, Taylor vortices are persistent leading to an axial periodicity of the flow. A detailed characterization of the vortices is performed for the single-phase flow. The experiment also develops bubbles tracking in a meridian plane and viscous torque of the inner cylinder measurements. The findings of this study show evidence of the link between bubbles localisation, Taylor vortices, and viscous torque modifications. We also highlight two regimes of viscous torque modification and various types of bubbles arrangements, depending on their size and on the Reynolds number. Bubbles can have a sliding and wavering motion near the inner cylinder and be either captured by the Taylor vortices or by the outflow areas near the inner cylinder. For small buoyancy effect, bubbles are trapped, leading to an increase of the viscous torque. When buoyancy induced bubbles motion is increased by comparison to the coherent motion of the liquid, a decrease in the viscous torque is rather observed. The type of bubble arrangement is parameterized by the two dimensionless parameters C and H introduced by Climent et al. ["Preferential accumulation of bubbles in Couette-Taylor flow patterns," Phys. Fluids 19, 083301 (2007)]. Phase diagrams summarizing the various types of bubbles arrangements, viscous torque modifications, and axial wavelength evolution are

  6. About Military Sexual Trauma

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  7. Abdominal Trauma Revisited.

    Science.gov (United States)

    Feliciano, David V

    2017-11-01

    Although abdominal trauma has been described since antiquity, formal laparotomies for trauma were not performed until the 1800s. Even with the introduction of general anesthesia in the United States during the years 1842 to 1846, laparotomies for abdominal trauma were not performed during the Civil War. The first laparotomy for an abdominal gunshot wound in the United States was finally performed in New York City in 1884. An aggressive operative approach to all forms of abdominal trauma till the establishment of formal trauma centers (where data were analyzed) resulted in extraordinarily high rates of nontherapeutic laparotomies from the 1880s to the 1960s. More selective operative approaches to patients with abdominal stab wounds (1960s), blunt trauma (1970s), and gunshot wounds (1990s) were then developed. Current adjuncts to the diagnosis of abdominal trauma when serial physical examinations are unreliable include the following: 1) diagnostic peritoneal tap/lavage, 2) surgeon-performed ultrasound examination; 3) contrast-enhanced CT of the abdomen and pelvis; and 4) diagnostic laparoscopy. Operative techniques for injuries to the liver, spleen, duodenum, and pancreas have been refined considerably since World War II. These need to be emphasized repeatedly in an era when fewer patients undergo laparotomy for abdominal trauma. Finally, abdominal trauma damage control is a valuable operative approach in patients with physiologic exhaustion and multiple injuries.

  8. About Military Sexual Trauma

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  12. About Military Sexual Trauma

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  13. Detonation wave phenomena in bubbled liquid

    Science.gov (United States)

    Gülhan, A.; Beylich, A. E.

    1990-07-01

    Shock wave propagation was investigated in two phase media consisting of diluted glycerin (85%) and reactive gas bubbles. To understand these complex phenomena, we first performed a numerical analysis and experimental studies of single bubbles containing a reactive gas-mixture. For the two-phase mixtures, a needle matrix bubble-generator enabled us to produce a homogeneous bubble distribution with a size dispersion less than 5%. The void fraction β0 was varied over one order of magnitude, β0=0.2-2%. It was found that there exists a critical value of shock strength above which bubble explosion starts. Once a bubble explodes, it stimulates the adjacent bubbles to explode due to emission of a blast wave; this process is followed by a series of similar events. A steady detonationlike wave propagates as a precurser with a constant velocity which is much higher than that of the first wave. To study the structure of the detonation wave the measured pressured profiles were averaged by superimposing 50 shots.

  14. The rheology of gravity driven bubbly liquids

    Science.gov (United States)

    Martinez-Mercado, Julian; Zenit, Roberto

    2002-11-01

    Experiments on a vertical channel were performed to to study the behavior of a monodispersed bubble suspension. Using water and water-glycerin mixtures, we were able to obtain measurements for a range of Reynolds and Weber numbers. To generate a uniform stream of bubbles an array of identical capillaries was used. To avoid the coalescence effects, a small amount of salt was added to the interstitial fluid, which did not affect the fluid properties significantly. Measurements of the bubble phase velocity were obtained using a dual impedance probe and through high speed digital video processing. We also obtained measurements of the bubble size and shape as a function of the gas volume fraction for the different flow regimes. We found that, for all cases, the bubble velocity decreases as mean gas volume fraction increases. The flow agitation, characterized with the bubble velocity variance, increases with bubble concentration. The flow becomes unstable for lower gas concentrations as the viscosity of the interstitial fluid increases.

  15. Shock waves from nonspherical cavitation bubbles

    Science.gov (United States)

    Supponen, Outi; Obreschkow, Danail; Kobel, Philippe; Tinguely, Marc; Dorsaz, Nicolas; Farhat, Mohamed

    2017-09-01

    We present detailed observations of the shock waves emitted at the collapse of single cavitation bubbles using simultaneous time-resolved shadowgraphy and hydrophone pressure measurements. The geometry of the bubbles is systematically varied from spherical to very nonspherical by decreasing their distance to a free or rigid surface or by modulating the gravity-induced pressure gradient aboard parabolic flights. The nonspherical collapse produces multiple shocks that are clearly associated with different processes, such as the jet impact and the individual collapses of the distinct bubble segments. For bubbles collapsing near a free surface, the energy and timing of each shock are measured separately as a function of the anisotropy parameter ζ , which represents the dimensionless equivalent of the Kelvin impulse. For a given source of bubble deformation (free surface, rigid surface, or gravity), the normalized shock energy depends only on ζ , irrespective of the bubble radius R0 and driving pressure Δ p . Based on this finding, we develop a predictive framework for the peak pressure and energy of shock waves from nonspherical bubble collapses. Combining statistical analysis of the experimental data with theoretical derivations, we find that the shock peak pressures can be estimated as jet impact-induced hammer pressures, expressed as ph=0.45 (ρc2Δ p ) 1 /2ζ-1 at ζ >10-3 . The same approach is found to explain the shock energy decreasing as a function of ζ-2 /3.

  16. Performance Tests for Bubble Blockage Device

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Kwang Soon; Wi, Kyung Jin; Park, Rae Joon; Wan, Han Seong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Postulated severe core damage accidents have a high threat risk for the safety of human health and jeopardize the environment. Versatile measures have been suggested and applied to mitigate severe accidents in nuclear power plants. To improve the thermal margin for the severe accident measures in high-power reactors, engineered corium cooling systems involving boiling-induced two-phase natural circulation have been proposed for decay heat removal. A boiling-induced natural circulation flow is generated in a coolant path between a hot vessel wall and cold coolant reservoir. In general, it is possible for some bubbles to be entrained in the natural circulation loop. If some bubbles entrain in the liquid phase flow passage, flow instability may occur, that is, the natural circulation mass flow rate may be oscillated. A new device to block the entraining bubbles is proposed and verified using air-water test loop. To avoid bubbles entrained in the natural circulation flow loop, a new device was proposed and verified using an air-water test loop. The air injection and liquid circulation loop was prepared, and the tests for the bubble blockage devices were performed by varying the geometry and shape of the devices. The performance of the bubble blockage device was more effective as the area ratio of the inlet to the down-comer increased, and the device height decreased. If the device has a rim to generate a vortex zone, the bubbles will be most effectively blocked.

  17. Bubbles in live-stranded dolphins.

    Science.gov (United States)

    Dennison, S; Moore, M J; Fahlman, A; Moore, K; Sharp, S; Harry, C T; Hoppe, J; Niemeyer, M; Lentell, B; Wells, R S

    2012-04-07

    Bubbles in supersaturated tissues and blood occur in beaked whales stranded near sonar exercises, and post-mortem in dolphins bycaught at depth and then hauled to the surface. To evaluate live dolphins for bubbles, liver, kidneys, eyes and blubber-muscle interface of live-stranded and capture-release dolphins were scanned with B-mode ultrasound. Gas was identified in kidneys of 21 of 22 live-stranded dolphins and in the hepatic portal vasculature of 2 of 22. Nine then died or were euthanized and bubble presence corroborated by computer tomography and necropsy, 13 were released of which all but two did not re-strand. Bubbles were not detected in 20 live wild dolphins examined during health assessments in shallow water. Off-gassing of supersaturated blood and tissues was the most probable origin for the gas bubbles. In contrast to marine mammals repeatedly diving in the wild, stranded animals are unable to recompress by diving, and thus may retain bubbles. Since the majority of beached dolphins released did not re-strand it also suggests that minor bubble formation is tolerated and will not lead to clinically significant decompression sickness.

  18. Inert gas bubbles in bcc Fe

    Energy Technology Data Exchange (ETDEWEB)

    Gai, Xiao, E-mail: windgx22@hotmail.com; Smith, Roger, E-mail: r.smith@lboro.ac.uk; Kenny, S.D., E-mail: masdk@lboro.ac.uk

    2016-03-15

    The properties of inert gas bubbles in bcc Fe is examined using a combination of static energy minimisation, molecular dynamics and barrier searching methods with empirical potentials. Static energy minimisation techniques indicate that for small Ar and Xe bubbles, the preferred gas to vacancy ratio at 0 K is about 1:1 for Ar and varies between 0.5:1 and 0.9:1 for Xe. In contrast to interstitial He atoms and small He interstitial clusters, which are highly mobile in the lattice, Ar and Xe atoms prefer to occupy substitutional sites and any interstitials present in the lattice soon displace Fe atoms and become substitutional. If a pre-existing bubble is present then there is a capture radius around a bubble which extends up to the 6th neighbour position. Collision cascades can also enlarge an existing bubble by the capture of vacancies. Ar and Xe can diffuse through the lattice through vacancy driven mechanisms but with relatively high energy barriers of 1.8 and 2.0 eV respectively. This indicates that Ar and Xe bubbles are much harder to form than bubbles of He and that such gases produced in a nuclear reaction would more likely be dispersed at substitutional sites without the help of increased temperature or radiation-driven mechanisms.

  19. Pressure waves in a supersaturated bubbly magma

    Science.gov (United States)

    Kurzon, I.; Lyakhovsky, V.; Navon, O.; Chouet, B.

    2011-01-01

    We study the interaction of acoustic pressure waves with an expanding bubbly magma. The expansion of magma is the result of bubble growth during or following magma decompression and leads to two competing processes that affect pressure waves. On the one hand, growth in vesicularity leads to increased damping and decreased wave amplitudes, and on the other hand, a decrease in the effective bulk modulus of the bubbly mixture reduces wave velocity, which in turn, reduces damping and may lead to wave amplification. The additional acoustic energy originates from the chemical energy released during bubble growth. We examine this phenomenon analytically to identify conditions under which amplification of pressure waves is possible. These conditions are further examined numerically to shed light on the frequency and phase dependencies in relation to the interaction of waves and growing bubbles. Amplification is possible at low frequencies and when the growth rate of bubbles reaches an optimum value for which the wave velocity decreases sufficiently to overcome the increased damping of the vesicular material. We examine two amplification phase-dependent effects: (1) a tensile-phase effect in which the inserted wave adds to the process of bubble growth, utilizing the energy associated with the gas overpressure in the bubble and therefore converting a large proportion of this energy into additional acoustic energy, and (2) a compressive-phase effect in which the pressure wave works against the growing bubbles and a large amount of its acoustic energy is dissipated during the first cycle, but later enough energy is gained to amplify the second cycle. These two effects provide additional new possible mechanisms for the amplification phase seen in Long-Period (LP) and Very-Long-Period (VLP) seismic signals originating in magma-filled cracks.

  20. Numerical investigation of bubble nonlinear dynamics characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Jie, E-mail: shijie@hrbeu.edu.cn; Yang, Desen; Shi, Shengguo; Hu, Bo [Acoustic Science and Technology Laboratory, Harbin Engineering University, Harbin 150001 (China); College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001 (China); Zhang, Haoyang; Jiang, Wei [College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001 (China)

    2015-10-28

    The complicated dynamical behaviors of bubble oscillation driven by acoustic wave can provide favorable conditions for many engineering applications. On the basis of Keller-Miksis model, the influences of control parameters, including acoustic frequency, acoustic pressure and radius of gas bubble, are discussed by utilizing various numerical analysis methods, Furthermore, the law of power spectral variation is studied. It is shown that the complicated dynamic behaviors of bubble oscillation driven by acoustic wave, such as bifurcation and chaos, further the stimulated scattering processes are revealed.

  1. Single DNA denaturation and bubble dynamics

    DEFF Research Database (Denmark)

    Metzler, Ralf; Ambjörnsson, Tobias; Hanke, Andreas

    2009-01-01

    While the Watson-Crick double-strand is the thermodynamically stable state of DNA in a wide range of temperature and salt conditions, even at physiological conditions local denaturation bubbles may open up spontaneously due to thermal activation. By raising the ambient temperature, titration......, or by external forces in single molecule setups bubbles proliferate until full denaturation of the DNA occurs. Based on the Poland-Scheraga model we investigate both the equilibrium transition of DNA denaturation and the dynamics of the denaturation bubbles with respect to recent single DNA chain experiments...

  2. A view inside the Gargamelle bubble chamber

    CERN Multimedia

    1970-01-01

    Gargamelle was the name given to a big bubble chamber built at the Saclay Laboratory in France during the late 1960s. It was designed principally for the detection at CERN of the elusive particles called neutrinos. A bubble chamber contains a liquid under pressure, which reveals the tracks of electrically charged particles as trails of tiny bubbles when the pressure is reduced. Neutrinos have no charge, and so leave no tracks, but the aim with Gargamelle was "see neutrinos" by making visible any charged particles set in motion by the interaction of neutrinos in the liquid

  3. Experimental investigation of shock wave - bubble interaction

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, Mohsen

    2010-04-09

    In this work, the dynamics of laser-generated single cavitation bubbles exposed to lithotripter shock waves has been investigated experimentally. The energy of the impinging shock wave is varied in several steps. High-speed photography and pressure field measurements simultaneously with image acquisition provide the possibility of capturing the fast bubble dynamics under the effect of the shock wave impact. The pressure measurement is performed using a fiber optic probe hydrophone (FOPH) which operates based on optical diagnostics of the shock wave propagating medium. After a short introduction in chapter 1 an overview of the previous studies in chapter 2 is presented. The reported literatures include theoretical and experimental investigations of several configurations of physical problems in the field of bubble dynamics. In chapter 3 a theoretical description of propagation of a shock wave in a liquid like water has been discussed. Different kinds of reflection of a shock wave at an interface are taken into account. Undisturbed bubble dynamics as well as interaction between a planar shock wave and an initially spherical bubble are explored theoretically. Some physical parameters which are important in this issue such as the velocity of the shock-induced liquid jet, Kelvin impulse and kinetic energy are explained. The shock waves are generated in a water filled container by a focusing piezoelectric generator. The shock wave profile has a positive part with pulse duration of ∼1 μs followed by a longer tension tail (i.e. ∼3 μs). In chapter 4 high-speed images depict the propagation of a shock wave in the water filled tank. The maximum pressure is also derived for different intensity levels of the shock wave generator. The measurement is performed in the free field (i.e. in the absence of laser-generated single bubbles). In chapter 5 the interaction between lithotripter shock waves and laserinduced single cavitation bubbles is investigated experimentally. An

  4. Arrested Bubble Rise in a Narrow Tube

    Science.gov (United States)

    Lamstaes, Catherine; Eggers, Jens

    2017-05-01

    If a long air bubble is placed inside a vertical tube closed at the top it can rise by displacing the fluid above it. However, Bretherton found that if the tube radius, R, is smaller than a critical value Rc=0.918 ℓ _c, where ℓ _c=√{γ /ρ g} is the capillary length, there is no solution corresponding to steady rise. Experimentally, the bubble rise appears to have stopped altogether. Here we explain this observation by studying the unsteady bubble motion for Rmotion.

  5. The bubbling galactic plane: fertilization or sterilization?

    Science.gov (United States)

    Testi, Leonardo; Cunningham, Maria; Zavagno, Annie; Deharveng, Lise; Leurini, Silvia; Molinari, Sergio

    2010-04-01

    Spitzer surveys have revealed that the galactic plane has a high density of bubbles. Many of these show evidence of being associated with star formation. Followup observations collected so far have failed to conclusively determine the relationship (if any) between the bubbles and the triggering of star formation. We propose to obtain MOPRA molecular line pointed observations towards bubbles detected with APEX in the millimeter continuum and with Herschel in the far infrared/submm to reveal the presence and kinematics of dense gas and to search for evidence of the initial phases of star formation.

  6. Bubble Size Distributions on the North Atlantic and North Sea

    NARCIS (Netherlands)

    Leeuw, G. de; Cohen, L.H.

    2002-01-01

    Bubble size distributions were measured at open sea with optical bubble measuring systems(BMS)deployed from buoys at depths from 0.4 to l.5m. The BMS measures the bubbles in a small sample volume that is monitored with a video camera. The images are analyzed to obtain bubble size distributions in

  7. MARANGONI CONVECTION AROUND A VENTILATED AIR BUBBLE UNDER MICROGRAVITY CONDITIONS

    NARCIS (Netherlands)

    HOEFSLOOT, HCJ; JANSSEN, LPBM; HOOGSTRATEN, HW

    Under microgravity conditions in both parabolic and sounding rocket flights, the mass-transfer-induced Marangoni convection around an air bubble was studied. To prevent the bubble from becoming saturated, the bubble was ventilated. It turned out that the flow rate of the air through the bubble

  8. Stability of a bubble expanding and translating through an inviscid ...

    Indian Academy of Sciences (India)

    A bubble expands adiabatically and translates in an incompressible and inviscid liquid. We investigate the number of equilibrium points of the bubble and the nature of stability of the bubble at these points. We find that there is only one equilibrium point and the bubble is stable there.

  9. Approach to universality in axisymmetric bubble pinch-off

    NARCIS (Netherlands)

    Gekle, S.; Snoeijer, Jacobus Hendrikus; Lohse, Detlef; van der Meer, Roger M.

    2009-01-01

    The pinch-off of an axisymmetric air bubble surrounded by an inviscid fluid is compared in four physical realizations: (i) cavity collapse in the wake of an impacting disk, (ii) gas bubbles injected through a small orifice, (iii) bubble rupture in a straining flow, and (iv) a bubble with an

  10. 21 CFR 870.4205 - Cardiopulmonary bypass bubble detector.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass bubble detector. 870.4205... bypass bubble detector. (a) Identification. A cardiopulmonary bypass bubble detector is a device used to detect bubbles in the arterial return line of the cardiopulmonary bypass circuit. (b) Classification...

  11. Stochastic DSMC method for dense bubbly flows : Methodology

    NARCIS (Netherlands)

    Kamath, S.; Padding, J.T.; Buist, K. A.; Kuipers, J.

    2018-01-01

    A stochastic Direct Simulation Monte Carlo (DSMC) method has been extended for handling bubble-bubble and bubble-wall collisions. Bubbly flows are generally characterized by highly correlated velocities due to presence of the surrounding liquid. The DSMC method has been improved to account for

  12. Conservation of bubble size distribution during gas reactive absorption in bubble column reactors

    Directory of Open Access Journals (Sweden)

    P. L.C. LAGE

    1999-12-01

    Full Text Available Conservation of the bubble size distribution function was applied to the reactive absorption of carbon dioxide in a bubble column reactor. The model developed was solved by the method of characteristics and by a Monte Carlo method. Simulations were carried out using simplified models for the liquid phase and for the gas-liquid mass transfer. Predictions of gas holdup and outlet gas composition showed that the concept of a mean bubble diameter is not applicable when the bubble size distribution is reasonably polydispersed. In these cases, the mass mean velocity and the numerical mean velocity of the bubbles are very different. Therefore, quantification of the polydispersion of bubbles was shown to be essential to gas-phase hydrodynamics modeling.

  13. The concentration distribution around a growing gas bubble in a bio tissue under the effect of suction process.

    Science.gov (United States)

    Mohammadein, S A

    2014-07-01

    The concentration distribution around a growing nitrogen gas bubble in the blood and other bio tissues of divers who ascend to surface too quickly is obtained by Mohammadein and Mohamed model (2010) for variant and constant ambient pressure through the decompression process. In this paper, the growing of gas bubbles and concentration distribution under the effect of suction process are studied as a modification of Mohammadein and Mohamed model (zero suction). The growth of gas bubble is affected by ascent rate, tissue diffusivity, initial concentration difference, surface tension and void fraction. Mohammadein and Mohamed model (2010) is obtained as a special case from the present model. Results showed that, the suction process activates the systemic blood circulation and delay the growth of gas bubbles in the bio tissues to avoid the incidence of decompression sickness (DCS). Copyright © 2014 Elsevier Inc. All rights reserved.

  14. IMPLEMENTATION OF SERIAL AND PARALLEL BUBBLE SORT ON FPGA

    Directory of Open Access Journals (Sweden)

    Dwi Marhaendro Jati Purnomo

    2016-06-01

    Full Text Available Sorting is common process in computational world. Its utilization are on many fields from research to industry. There are many sorting algorithm in nowadays. One of the simplest yet powerful is bubble sort. In this study, bubble sort is implemented on FPGA. The implementation was taken on serial and parallel approach. Serial and parallel bubble sort then compared by means of its memory, execution time, and utility which comprises slices and LUTs. The experiments show that serial bubble sort required smaller memory as well as utility compared to parallel bubble sort. Meanwhile, parallel bubble sort performed faster than serial bubble sort

  15. Time-Dependent Changes in a Shampoo Bubble

    Science.gov (United States)

    Chattopadhyay, Arun

    2000-10-01

    This article demonstrates the fascinating phenomenon of time evolution of a shampoo bubble through experiments that can be performed by undergraduate students. The changes in thickness of the bubble films with time are followed by UV-vis spectroscopy. The change in chemical composition as a bubble film evolves is monitored by FTIR spectroscopy. It is observed that the change in thickness of a typical shampoo bubble film enclosed in a container is gradual and slow, and the hydrocarbon components of the bubble drain from the bubble much more slowly than water. An additional agent, such as acetonitrile, strikingly alters the dynamics of evolution of such a bubble.

  16. Lattice Boltzmann Simulation of Multiple Bubbles Motion under Gravity

    Directory of Open Access Journals (Sweden)

    Deming Nie

    2015-01-01

    Full Text Available The motion of multiple bubbles under gravity in two dimensions is numerically studied through the lattice Boltzmann method for the Eotvos number ranging from 1 to 12. Two kinds of initial arrangement are taken into account: vertical and horizontal arrangement. In both cases the effects of Eotvos number on the bubble coalescence and rising velocity are investigated. For the vertical arrangement, it has been found that the coalescence pattern is similar. The first coalescence always takes place between the two uppermost bubbles. And the last coalescence always takes place between the coalesced bubble and the bottommost bubble. For four bubbles in a horizontal arrangement, the outermost bubbles travel into the wake of the middle bubbles in all cases, which allows the bubbles to coalesce. The coalescence pattern is more complex for the case of eight bubbles, which strongly depends on the Eotvos number.

  17. Stationary bubble formation and cavity collapse in wedge-shaped hoppers

    CERN Document Server

    Yagisawa, Yui; Okumura, Ko

    2016-01-01

    The hourglass is one of the apparatuses familiar to everyone, but reveals intriguing behaviors peculiar to granular materials, and many issues are remained to be explored. In this study, we examined the dynamics of falling sand in a special form of hourglass, i.e., a wedge-shaped hopper, when a suspended granular layer is stabilized to a certain degree. As a result, we found remarkably different dynamics, bubbling and cavity regimes. In the bubbling regime, bubbles of nearly equal size are created in the sand at a regular time interval. In the cavity regime, a cavity grows as sand beads fall before a sudden collapse of the cavity. Bubbling found here is quite visible to a level never discussed in the physics literature and the cavity regime is a novel phase, which is neither continuous, intermittent nor completely blocked phase. We elucidate the physical conditions necessary for the bubbling and cavity regimes and develop simple theories for the regimes to successfully explain the observed phenomena by consid...

  18. Virtual Trauma Team

    NARCIS (Netherlands)

    Jones, Valerie M.; Bults, Richard G.A.

    2001-01-01

    The clinical motivation for Virtual Trauma Team is to improve quality of care in trauma care in the vital first "golden hour" where correct intervention can greatly improve likely health outcome. The motivation for Virtual Homecare Team is to improve quality of life and independence for patients by

  19. Prospects after Major Trauma

    NARCIS (Netherlands)

    Holtslag, H.R.

    2007-01-01

    Introduction. After patients survived major trauma, their prospects, in terms of the consequences for functioning, are uncertain, which may impact severely on patient, family and society. The studies in this thesis describes the long-term outcomes of severe injured patients after major trauma. In

  20. Optimization of the bubble radius in a moving single bubble sonoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Mirheydari, Mona; Sadighi-Bonabi, Rasoul; Rezaee, Nastaran; Ebrahimi, Homa, E-mail: sadighi@sharif.ir [Department of Physics, Sharif University of Technology, 11365-91, Tehran (Iran, Islamic Republic of)

    2011-05-01

    A complete study of the hydrodynamic force on a moving single bubble sonoluminescence in N-methylformamide is presented in this work. All forces exerted, trajectory, interior temperature and gas pressure are discussed. The maximum values of the calculated components of the hydrodynamic force for three different radii at the same driving pressure were compared, while the optimum bubble radius was determined. The maximum value of the buoyancy force appears at the start of bubble collapse, earlier than the other forces whose maximum values appear at the moment of bubble collapse. We verified that for radii larger than the optimum radius, the temperature peak value decreases.

  1. Chaotic behavior in bubble formation dynamics

    Science.gov (United States)

    Tufaile, A.; Sartorelli, J. C.

    2000-01-01

    We constructed an experimental apparatus to study the dynamics of the formation of air bubbles in a submerged nozzle in a water/glycerin solution inside a cylindrical tube. The delay time between successive bubbles was measured with a laser-photodiode system. It was observed bifurcations, chaotic behavior, and sudden changes in a periodic regime as a function of the decreasing air pressure in a reservoir. We also observed dynamical effects by applying a sound wave tuned to the fundamental frequency of the air column above the solution. As a function of the sound wave amplitude, we obtained a limit cycle, a flip bifurcation, chaotic behavior, and the synchronization of the bubbling with sound wave frequency. We related some of the different dynamical behaviors to coalescent effects and bubble sizes.

  2. Large bubble entrainment in drop impact

    Science.gov (United States)

    Thoraval, Marie-Jean; Li, Yangfan; Thoroddsen, Sigurdur T.

    2015-11-01

    A drop impacting on a pool of the same liquid can entrap air bubbles in many different ways. A peculiar entrapment was observed by Pumphrey and Elmore (1990) and remained unexplained until now. For a small range of parameters, the cavity produced by the impacting drop spreads radially in a dish-shape and then closes to entrap a bubble larger than the drop. We demonstrate that the large bubble is caused by a vortex ring produced in the liquid during the impact of the drop. We combine experiments and numerical simulations to show that the vortex ring pulls on the interface on the side of the cavity to stretch it radially, explaining the shape of the cavity. Only prolate drops are able to generate large bubbles. This is due to the self-destruction of the vortex earlier during the impact for flatter drops.

  3. On the shape of giant soap bubbles.

    Science.gov (United States)

    Cohen, Caroline; Darbois Texier, Baptiste; Reyssat, Etienne; Snoeijer, Jacco H; Quéré, David; Clanet, Christophe

    2017-03-07

    We study the effect of gravity on giant soap bubbles and show that it becomes dominant above the critical size [Formula: see text], where [Formula: see text] is the mean thickness of the soap film and [Formula: see text] is the capillary length ([Formula: see text] stands for vapor-liquid surface tension, and [Formula: see text] stands for the liquid density). We first show experimentally that large soap bubbles do not retain a spherical shape but flatten when increasing their size. A theoretical model is then developed to account for this effect, predicting the shape based on mechanical equilibrium. In stark contrast to liquid drops, we show that there is no mechanical limit of the height of giant bubble shapes. In practice, the physicochemical constraints imposed by surfactant molecules limit the access to this large asymptotic domain. However, by an exact analogy, it is shown how the giant bubble shapes can be realized by large inflatable structures.

  4. The Soap-Bubble-Geometry Contest.

    Science.gov (United States)

    Morgan, Frank; Melnick, Edward R.; Nicholson, Ramona

    1997-01-01

    Presents an activity on soap-bubble geometry using a guessing contest, explanations, and demonstrations that allow students to mesh observation and mathematical reasoning to discover that mathematics is much more than just number crunching. (ASK)

  5. TE Scattering From Bubbles In RAM

    National Research Council Canada - National Science Library

    Cochran, John

    1999-01-01

    ... (00) to 450 and at a frequency range from 2-18 GHz, TE polarization. The results from the absolute RCS measurement of the various sized RAM bubbles are discussed in terms of a frequency dependent increase in RCS...

  6. Test and evaluation of bubble memories

    Science.gov (United States)

    Bahm, E.

    1978-01-01

    A description is presented of a test program which has shown that well-constructed bubble memories can operate reliably over long periods of time and at low error rates. Even the relatively high error rate of one memory during burn-in can be considered acceptable if compared with tape recorder standards. No wear-out mechanism or aging could be detected. Bubble memories are now considered suitable for long-duration space missions and certainly are suitable for many military and commercial applications. It must be recognized, however, that bubble memories are complex devices and not yet fully understood. While the particular memory tested may never find practical applications, it nevertheless has provided insight into performance characteristics considered typical of bubble memories.

  7. [Thoracic Trauma - Prehospital Treatment].

    Science.gov (United States)

    Hansen, Michael; Hachenberg, Thomas

    2017-06-01

    Penetrating thoracic injuries are rare in Germany and common in urban regions. 10 percent of the patients in Emergency Departments suffer from blunt thoracic trauma. Mechanism of trauma can predict the severity of the injuries. Very fast life-threatening injuries with hemodynamic problems like tension pneumothorax or cardiac tamponade have to be diagnosed. Prehospital emergency physicians need skills in ultrasound for diagnosis and in invasive therapy like chest tube or pericardium drainage tube. The application of an algorithm in exploration of a thoracic trauma seems to be useful. The selection of trauma center depends on the severity of the trauma, if necessary with the availability of extracorporeal circulation. Georg Thieme Verlag KG Stuttgart · New York.

  8. Haemostatic resuscitation in trauma

    DEFF Research Database (Denmark)

    Stensballe, Jakob; Ostrowski, Sisse Rye; Johansson, Par I.

    2016-01-01

    PURPOSE OF REVIEW: To discuss the recent developments in and evolvement of next generation haemostatic resuscitation in bleeding trauma. RECENT FINDINGS: Mortality from major trauma is a worldwide problem, and massive haemorrhage remains a major cause of potentially preventable deaths. Development...... of coagulopathy further increases trauma mortality emphasizing that coagulopathy is a key target in the phase of bleeding. The pathophysiology of coagulopathy in trauma reflects at least three distinct mechanisms that may be present isolated or coexist: acute traumatic coagulopathy, coagulopathy associated...... with the lethal triad, and consumptive coagulopathy. The concepts of 'damage control surgery' and 'damage control resuscitation' have been developed to ensure early control of bleeding and coagulopathy to improve outcome in bleeding trauma. Haemostatic resuscitation aims at controlling coagulopathy and consists...

  9. Dental Trauma Guide

    DEFF Research Database (Denmark)

    Andreasen, Jens Ove; Lauridsen, Eva Fejerskov; Christensen, Søren Steno Ahrensburg

    2012-01-01

    Diagnose and treatment of traumatic dental injuries is very complex due to the multiple trauma entities represented by 6 lunation types and 9 fracture types affecting both the primary and the permanent dentition. When it is further considered that fracture and lunation injuries are often combined......, the result is, that more than 100 trauma scenario exist when the two dentitions are combined. Each of these trauma scenarios have a specific treatment demand and prospect for healing. With such a complexity in diagnose and treatment it is obvious that even experienced practitioners may have problems may have...... problems in selecting proper treatment for some of these trauma types. To remedy this situation, an internet based knowledge base consisting of 4000 dental trauma cases with long term follow up is now available to the public and professionals, on the internet using the address www...

  10. Trauma-induced coagulopathy.

    Science.gov (United States)

    Katrancha, Elizabeth D; Gonzalez, Luis S

    2014-08-01

    Coagulopathy is the inability of blood to coagulate normally; in trauma patients, it is a multifactorial and complex process. Seriously injured trauma patients experience coagulopathies during the acute injury phase. Risk factors for trauma-induced coagulopathy include hypothermia, metabolic acidosis, hypoperfusion, hemodilution, and fluid replacement. In addition to the coagulopathy induced by trauma, many patients may also be taking medications that interfere with hemostasis. Therefore, medication-induced coagulopathy also is a concern. Traditional laboratory-based methods of assessing coagulation are being supported or even replaced by point-of-care tests. The evidence-based management of trauma-induced coagulopathy should address hypothermia, fluid resuscitation, blood components administration, and, if needed, medications to reverse identified coagulation disorders. ©2014 American Association of Critical-Care Nurses.

  11. Electron acceleration in the bubble regime

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, Oliver

    2014-02-03

    The bubble regime of laser-wakefield acceleration has been studied over the recent years as an important alternative to classical accelerators. Several models and theories have been published, in particular a theory which provides scaling laws for acceleration parameters such as energy gain and acceleration length. This thesis deals with numerical simulations within the bubble regime, their comparison to these scaling laws and data obtained from experiments, as well as some specific phenomenona. With a comparison of the scaling laws with numerical results a parameter scan was able to show a large parameter space in which simulation and theory agree. An investigation of the limits of this parameter space revealed boundaries to other regimes, especially at very high (a{sub 0} > 100) and very low laser amplitudes (a{sub 0} < 4). Comparing simulation data with data from experiments concerning laser pulse development and electron energies, it was found that experimental results can be adequately reproduced using the Virtual-Laser-Plasma-Laboratory code. In collaboration with the Institut fuer Optik und Quantenelektronik at the Friedrich-Schiller University Jena synchrotron radiation emitted from the inside of the bubble was investigated. A simulation of the movement of the electrons inside the bubble together with time dependent histograms of the emitted radiation helped to prove that the majority of radiation created during a bubble acceleration originates from the inside of the bubble. This radiation can be used to diagnose the amplitude of oscillation of the trapped electrons. During a further study it was proven that the polarisation of synchrotron radiation from a bubble contains information about the exact oscillation direction. This oscillation was successfully controlled by using either a laser pulse with a tilted pulse front or an asymmetric laser pulse. First results of ongoing studies concerning injecting electrons into an existing bubble and a scheme called

  12. Nasal injury and comfort with jet versus bubble continuous positive airway pressure delivery systems in preterm infants with respiratory distress.

    Science.gov (United States)

    Khan, Jafar; Sundaram, Venkataseshan; Murki, Srinivas; Bhatti, Anuj; Saini, Shiv Sajan; Kumar, Praveen

    2017-12-01

    Nasal injuries with use of nasal continuous positive airway pressure (CPAP) range from blanching of nasal tip to septal necrosis and septal drop. This analysis was done in preterm neonates of Bubble device for delivery of CPAP, both through nasal prongs of different structure, make and fixation methods. Nasal injury was assessed using a validated nasal injury score. Out of 170 neonates enrolled, 103 (61%) had nasal injuries; moderate and severe injuries were observed in 18 (11%) and 8 (5%) infants, respectively. Septum was the most common site injured. The incidence and severity of nasal injury were significantly lesser in Jet group compared to Bubble group [RR 0.6 (95% C.I. 0.5-0.8); p Bubble group. However, Jet group neonates had significantly more common prong displacements. Bubble CPAP device with its nasal interface had higher and more serious incidence of nasal injuries in comparison to Jet CPAP device. What is known: • Nasal injuries are becoming increasingly common with use of nasal CPAP low gestational age, low birth weight, longer use of CPAP and longer NICU stay are risk factors for such injuries • Validated nasal injury scores have been created for assessment of nasal trauma in neonates What is new: • Bubble device with its interface had higher and more serious incidence of nasal injuries in comparison to Jet device • Even though pain assessed by N-PASS was less with Jet device, prong displacements were more frequent with its system.

  13. Numerical simulation of single bubble boiling behavior

    Directory of Open Access Journals (Sweden)

    Junjie Liu

    2017-06-01

    Full Text Available The phenomena of a single bubble boiling process are studied with numerical modeling. The mass, momentum, energy and level set equations are solved using COMSOL multi-physics software. The bubble boiling dynamics, the transient pressure field, velocity field and temperature field in time are analyzed, and reasonable results are obtained. The numeral model is validated by the empirical equation of Fritz and could be used for various applications.

  14. Test ventilation with smoke, bubbles, and balloons

    Energy Technology Data Exchange (ETDEWEB)

    Pickering, P.L.; Cucchiara, A.L.; McAtee, J.L.; Gonzales, M.

    1987-01-01

    The behavior of smoke, bubbles, and helium-filled balloons was videotaped to demonstrate the mixing of air in the plutonium chemistry laboratories, a plutonium facility. The air-distribution patterns, as indicated by each method, were compared. Helium-filled balloons proved more useful than bubbles or smoke in the visualization of airflow patterns. The replay of various segments of the videotape proved useful in evaluating the different techniques and in identifying airflow trends responsible for air mixing. 6 refs.

  15. Blunt Force Trauma in Veterinary Forensic Pathology.

    Science.gov (United States)

    Ressel, L; Hetzel, U; Ricci, E

    2016-09-01

    Veterinary pathologists commonly encounter lesions of blunt trauma. The development of lesions is affected by the object's mass, velocity, size, shape, and angle of impact and by the plasticity and mobility of the impacted organ. Scrape, impact, and pattern abrasions cause localized epidermal loss and sometimes broken hairs and implanted foreign material. Contusions are best identified after reflecting the skin, and must be differentiated from coagulopathies and livor mortis. Lacerations-traumatic tissue tears-may have irregular margins, bridging by more resilient tissue, deviation of the wound tail, crushed hairs, and unilateral abrasion. Hanging or choking can cause circumferential cervical abrasions, contusions and rupture of hairs, hyoid bone fractures, and congestion of the head. Other special forms of blunt trauma include fractured nails, pressure sores, and dog bites. Ocular blunt trauma causes extraocular and intraocular hemorrhages, proptosis, or retinal detachment. The thoracic viscera are relatively protected from blunt trauma but may develop hemorrhages in intercostal muscles, rib fractures, pulmonary or cardiac contusions or lacerations with subsequent hemothorax, pneumothorax, or cardiac arrhythmia. The abdominal wall is resilient and moveable, yet the liver and spleen are susceptible to traumatic laceration or rupture. Whereas extravasation of blood can occur after death, evidence of vital injury includes leukocyte infiltration, erythrophagocytosis, hemosiderin, reparative lesions of fibroblast proliferation, myocyte regeneration in muscle, and callus formation in bone. Understanding these processes aids in the diagnosis of blunt force trauma including estimation of the age of resulting injuries. © The Author(s) 2016.

  16. Fluid dynamics of bubbles in liquid

    Directory of Open Access Journals (Sweden)

    C.M. SCHEID

    1999-12-01

    Full Text Available Results gathered from the literature on the dynamics of bubbles in liquid are correlated by means of a formulation traditionally employed to describe the dynamics of isometric solid particles. It is assumed that the shape of the bubble depends, by means of the Eotvos number, on its diameter and on the gas-liquid surface tension. The analysis reported herein includes the dynamics of the isolated bubble along with wall and concentration effects. However, the effects of gas circulation in the bubble, which result in terminal velocities higher than those of a rigid sphere, are not being considered. A limited number of experimental points are obtained employing a modified version of the Mariotte flask which permits the precise measure of bubble volume. A classic bubble column is also employed in order to measure gas holdup in the continuous phase. Experiments were carried out employing air, with distilled water, potable water, water with variable amounts of surfactant and glycerin as the liquid phase.

  17. Gas Bubble Dynamics under Mechanical Vibrations

    Science.gov (United States)

    Mohagheghian, Shahrouz; Elbing, Brian

    2017-11-01

    The scientific community has a limited understanding of the bubble dynamics under mechanical oscillations due to over simplification of Navier-Stockes equation by neglecting the shear stress tensor and not accounting for body forces when calculating the acoustic radiation force. The current work experimental investigates bubble dynamics under mechanical vibration and resulting acoustic field by measuring the bubble size and velocity using high-speed imaging. The experimental setup consists of a custom-designed shaker table, cast acrylic bubble column, compressed air injection manifold and an optical imaging system. The mechanical vibrations resulted in accelerations between 0.25 to 10 times gravitational acceleration corresponding to frequency and amplitude range of 8 - 22Hz and 1 - 10mm respectively. Throughout testing the void fraction was limited to bubble size is larger than resonance size and smaller than acoustic wavelength. The amplitude of acoustic pressure wave was estimated using the definition of Bjerknes force in combination with Rayleigh-Plesset equation. Physical behavior of the system was capture and classified. Bubble size, velocity as well as size and spatial distribution will be presented.

  18. Fearless versus fearful speculative financial bubbles

    Science.gov (United States)

    Andersen, J. V.; Sornette, D.

    2004-06-01

    Using a recently introduced rational expectation model of bubbles, based on the interplay between stochasticity and positive feedbacks of prices on returns and volatility, we develop a new methodology to test how this model classifies nine time series that have been previously considered as bubbles ending in crashes. The model predicts the existence of two anomalous behaviors occurring simultaneously: (i) super-exponential price growth and (ii) volatility growth, that we refer to as the “fearful singular bubble” regime. Out of the nine time series, we find that five pass our tests and can be characterized as “fearful singular bubbles”. The four other cases are the information technology Nasdaq bubble and three bubbles of the Hang Seng index ending in crashes in 1987, 1994 and 1997. According to our analysis, these four bubbles have developed with essentially no significant increase of their volatility. This paper thus proposes that speculative bubbles ending in crashes form two groups hitherto unrecognized, namely those accompanied by increasing volatility (reflecting increasing risk perception) and those without change of volatility (reflecting an absence of risk perception).

  19. 'We don't have to go and see a special person to solve this problem': Trauma, mental health beliefs and processes for addressing 'mental health issues' among Sudanese refugees in Australia.

    Science.gov (United States)

    Savic, Michael; Chur-Hansen, Anna; Mahmood, Mohammad Afzal; Moore, Vivienne M

    2016-02-01

    The impact of trauma on refugee mental health has been a particular focal point for research and treatment in Western contexts, despite uncertainty about the degree to which this corresponds with refugees' needs, mental health beliefs and healing mechanisms. This study explored the mental health beliefs of resettling Sudanese refugees in Australia. In-depth qualitative interviews were conducted with Sudanese community representatives and with a range of health and social work professionals who were not necessarily Sudanese. The concept of trauma was not universally considered to be salient for Sudanese refugees. Key informants, especially those in refugee-oriented services, emphasised stoicism and a desire to move forward and questioned the appropriateness of Western psychological therapies. Processes that exist within the family and the Sudanese community to deal with stressors like loss, grief and social isolation were explained. Dialogue between services and community members is needed to ensure responses to refugee mental health are sensitive to the diversity of needs and mental health beliefs of refugees. This will enable workers to ascertain how individual refugees understand their experiences of distress or sadness and to determine whether community strategies and/or professional responses are appropriate. © The Author(s) 2015.

  20. Trauma in the elderly caused by traffic accident: integrative review

    Directory of Open Access Journals (Sweden)

    Ana Maria Ribeiro dos Santos

    2015-02-01

    Full Text Available OBJECTIVE To describe the scientific knowledge produced about trauma in the elderly caused by traffic accidents in healthcare area studies. METHODS Integrative review of studies from 2003 to 2013 searched in LILACS, SciELO, PubMed and CINHAL databases. We used combination of the descriptors injuries, wounds and accidents, in English, Portuguese and Spanish languages. RESULTS 32 studies were selected. In the thematic analysis, three categories emerged: epidemiological data from traffic accidents involving elderly; traffic accidents with elderly pedestrians; and trauma care in the elderly. We observed increased incidence of trauma in most countries and pedestrians represented a large part of the victims. Among these, the elderly are the most vulnerable group. CONCLUSION Studies showed that trauma care in the elderly need protocols and professionals with training in gerontology specialized in trauma care services.

  1. The Scientometric Bubble Considered Harmful.

    Science.gov (United States)

    Génova, Gonzalo; Astudillo, Hernán; Fraga, Anabel

    2016-02-01

    This article deals with a modern disease of academic science that consists of an enormous increase in the number of scientific publications without a corresponding advance of knowledge. Findings are sliced as thin as salami and submitted to different journals to produce more papers. If we consider academic papers as a kind of scientific 'currency' that is backed by gold bullion in the central bank of 'true' science, then we are witnessing an article-inflation phenomenon, a scientometric bubble that is most harmful for science and promotes an unethical and antiscientific culture among researchers. The main problem behind the scenes is that the impact factor is used as a proxy for quality. Therefore, not only for convenience, but also based on ethical principles of scientific research, we adhere to the San Francisco Declaration on Research Assessment when it emphasizes "the need to eliminate the use of journal-based metrics in funding, appointment and promotion considerations; and the need to assess research on its own merits rather on the journal in which the research is published". Our message is mainly addressed to the funding agencies and universities that award tenures or grants and manage research programmes, especially in developing countries. The message is also addressed to well-established scientists who have the power to change things when they participate in committees for grants and jobs.

  2. Evidence-Based Care of Geriatric Trauma Patients.

    Science.gov (United States)

    Brooks, Steven E; Peetz, Allan B

    2017-10-01

    The doubling of the geriatric population over the next 20 years will challenge the existing health care system. Optimal care of geriatric trauma patients will be of paramount importance to the health care discussion in America. These patients warrant special consideration because of altered anatomy, physiology, and the resultant decreased ability to tolerate the stresses imposed by traumatic insult. Despite increased risk for worsened outcomes, nearly half of all geriatric trauma patients will be cared for at nondesignated trauma centers. Effective communication is crucial in determining goals of care and arriving at what patients would consider a meaningful outcome. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Bubbles and semi-bubbles as a new kind of superheavy nuclei

    CERN Document Server

    Dechargé, J; Girod, M; Dietrich, K G

    2003-01-01

    Applying the HFB theory with the effective interaction D1S of Gogny, two kinds of 'hyperheavy nuclei' were discovered: true 'bubbles' with practically vanishing nuclear density in the central region of the nucleus, and 'semi-bubbles' ('unsaturated nuclei') with a reduced but finite density near the nuclear center. Semi-bubbles are found to be stable with regard to the emission of a neutron or a proton for nucleon numbers A and charge numbers Z in the ranges 292 < or approx. 750 and 120 < or approx. 240, and true bubbles for 750 < or approx. 920 and 240 < or approx. 280, respectively. For a limited number of nuclear species, a third type of hyperheavy nuclei with a finite, strongly reduced, halo-like central density ('internal halo nuclei') is found. Coexistence of bubble and semi-bubble solutions for given nucleon and charge numbers is frequently obtained, the semi-bubbles being the ground states for A < or approx. 240, and the true bubbles for the heavier nuclear species. The dominant disinteg...

  4. The importance of bubble deformability for strong drag reduction in bubbly turbulent Taylor-Couette flow

    NARCIS (Netherlands)

    van Gils, Dennis Paulus Maria; Narezo Guzman, Daniela; Sun, Chao; Lohse, Detlef

    2013-01-01

    Bubbly turbulent Taylor–Couette (TC) flow is globally and locally studied at Reynolds numbers of Re=5×105 to 2×106 with a stationary outer cylinder and a mean bubble diameter around 1 mm. We measure the drag reduction (DR) based on the global dimensional torque as a function of the global gas volume

  5. Trauma Induced Coagulopathy

    DEFF Research Database (Denmark)

    Genét, Gustav Folmer; Johansson, Per; Meyer, Martin Abild Stengaard

    2013-01-01

    It remains debated whether traumatic brain injury (TBI) induces a different coagulopathy compared to non-TBI. This study investigated traditional coagulation tests, biomarkers of coagulopathy and endothelial damage in trauma patients with and without TBI. Blood from 80 adult trauma patients were...... sampled (median of 68 min (IQR 48-88) post-injury) upon admission to our trauma centre. Plasma/serum were retrospectively analysed for biomarkers reflecting sympathoadrenal activation (adrenaline, noradrenaline), coagulation activation/inhibition and fibrinolysis (protein C, activated protein C, tissue...

  6. Urological injuries following trauma

    Energy Technology Data Exchange (ETDEWEB)

    Bent, C. [Department of Diagnostic Imaging, Barts and The London NHS Trust, London (United Kingdom)], E-mail: clare.bent@bartsandthelondon.nhs.uk; Iyngkaran, T.; Power, N.; Matson, M. [Department of Diagnostic Imaging, Barts and The London NHS Trust, London (United Kingdom); Hajdinjak, T.; Buchholz, N. [Department of Urology, Barts and The London NHS Trust, London (United Kingdom); Fotheringham, T. [Department of Diagnostic Imaging, Barts and The London NHS Trust, London (United Kingdom)

    2008-12-15

    Blunt renal trauma is the third most common injury in abdominal trauma following splenic and hepatic injuries, respectively. In the majority, such injuries are associated with other abdominal organ injuries. As urological injuries are not usually life-threatening, and clinical signs and symptoms are non-specific, diagnosis is often delayed. We present a practical approach to the diagnosis and management of these injuries based on our experience in a busy inner city trauma hospital with a review of the current evidence-based practice. Diagnostic imaging signs are illustrated.

  7. [Trauma-induced coagulopathy].

    Science.gov (United States)

    Hanke, A A; Rahe-Meyer, N

    2014-02-01

    The main cause of death in the patient group less than 45 years is trauma. Beside severe traumatic brain injury, bleeding remains a leading cause of death in this group. For a causal therapy, it is necessary to understand the pathophysiology of trauma-induced coagulopathy (TIC). Beside the well-known lethal triad of trauma (hypothermia, acidosis, and coagulopathy), dilution and hypoperfusion with activation of the protein C pathway play a crucial role. TIC is a complex independent syndrome which may be present without initial hypercoagulopathy. A rapid and differentiated diagnosis and goal-directed therapy is crucial for causal therapy.

  8. Dynamics and switching processes for magnetic bubbles in nanoelements

    Science.gov (United States)

    Moutafis, C.; Komineas, S.; Bland, J. A. C.

    2009-06-01

    We study numerically the dynamics of a magnetic bubble in a disk-shaped magnetic element which is probed by a pulse of a magnetic field gradient. Magnetic bubbles are nontrivial magnetic configurations which are characterized by a topological (skyrmion) number N and they have been observed in mesoscopic magnetic elements with strong perpendicular anisotropy. For weak fields we find a skew deflection of the axially symmetric N=1 bubble and a subsequent periodic motion around the center of the dot. This gyrotropic motion of the magnetic bubble is shown here for the first time. Stronger fields induce switching of the N=1 bubble to a bubble which contains a pair of Bloch lines and has N=0 . The N=0 bubble can be switched back to a N=1 bubble by applying again an external field gradient. Detailed features of the unusual bubble dynamics are described by employing the skyrmion number and the moments of the associated topological density.

  9. Real-time on-line ultrasonic monitoring for bubbles in ceramic 'slip' in pottery pipelines.

    Science.gov (United States)

    Yim, Geun Tae; Leighton, Timothy G

    2010-01-01

    When casting ceramic items in potteries, liquid 'slip' is passed from a settling tank, through overhead pipelines, before being pumped manually into the moulds. It is not uncommon for bubbles to be introduced into the slip as it passes through the complex piping network, and indeed the presence of bubbles is a major source of financial loss to the ceramics industry worldwide. This is because the bubbles almost always remain undetected until after the ceramic items have been fired in a kiln, during which process bubbles expand and create unwanted holes in the pottery. Since there it is usually an interval of several hours between the injection of the slip into the moulds, and the inspection of the items after firing, such bubble generation goes undetected on the production line during the manufacture of hundreds or even thousands of ceramic units. Not only does this mean hours of wasted staff time, power consumption and production line time: the raw material which makes up these faulty items cannot even be recycled, as fired ceramic cannot be converted back into slip. Currently, the state-of-the-art method for detecting bubbles in the opaque ceramic slip is slow and invasive, can only be used off-line, and requires expertise which is rarely available. This paper describes the invention, engineering and in-factory testing across Europe of an ultrasonic system for real-time monitoring for the presence of bubbles in casting slip. It interprets changes in the scattering statistics accompanying the presence of the bubbles, the latter being detected through perturbations in the received signal when a narrow-band ultrasonic probing wave is transmitted through the slip. The device can be bolted onto the outside of the pipeline, or used in-line. It is automated, and requires no special expertise. The acoustic problems which had to be solved were severe, and included making the system capable of monitoring the slip regardless of the material of pipe (plastic, steel, etc.) and

  10. Convective mass transfer around a dissolving bubble

    Science.gov (United States)

    Duplat, Jerome; Grandemange, Mathieu; Poulain, Cedric

    2017-11-01

    Heat or mass transfer around an evaporating drop or condensing vapor bubble is a complex issue due to the interplay between the substrate properties, diffusion- and convection-driven mass transfer, and Marangoni effects, to mention but a few. In order to disentangle these mechanisms, we focus here mainly on the convective mass transfer contribution in an isothermal mass transfer problem. For this, we study the case of a millimetric carbon dioxide bubble which is suspended under a substrate and dissolved into pure liquid water. The high solubility of CO2 in water makes the liquid denser and promotes a buoyant-driven flow at a high (solutal) Rayleigh number (Ra˜104 ). The alteration of p H allows the concentration field in the liquid to be imaged by laser fluorescence enabling us to measure both the global mass flux (bubble volume, contact angle) and local mass flux around the bubble along time. After a short period of mass diffusion, where the boundary layer thickens like the square root of time, convection starts and the CO2 is carried by a plume falling at constant velocity. The boundary layer thickness then reaches a plateau which depends on the bubble cross section. Meanwhile the plume velocity scales like (dV /d t )1 /2 with V being the volume of the bubble. As for the rate of volume loss, we recover a constant mass flux in the diffusion-driven regime followed by a decrease in the volume V like V2 /3 after convection has started. We present a model which agrees well with the bubble dynamics and discuss our results in the context of droplet evaporation, as well as high Rayleigh convection.

  11. Scaling laws and dynamics of bubble coalescence

    Science.gov (United States)

    Anthony, Christopher R.; Kamat, Pritish M.; Thete, Sumeet S.; Munro, James P.; Lister, John R.; Harris, Michael T.; Basaran, Osman A.

    2017-08-01

    The coalescence of bubbles and drops plays a central role in nature and industry. During coalescence, two bubbles or drops touch and merge into one as the neck connecting them grows from microscopic to macroscopic scales. The hydrodynamic singularity that arises when two bubbles or drops have just touched and the flows that ensue have been studied thoroughly when two drops coalesce in a dynamically passive outer fluid. In this paper, the coalescence of two identical and initially spherical bubbles, which are idealized as voids that are surrounded by an incompressible Newtonian liquid, is analyzed by numerical simulation. This problem has recently been studied (a) experimentally using high-speed imaging and (b) by asymptotic analysis in which the dynamics is analyzed by determining the growth of a hole in the thin liquid sheet separating the two bubbles. In the latter, advantage is taken of the fact that the flow in the thin sheet of nonconstant thickness is governed by a set of one-dimensional, radial extensional flow equations. While these studies agree on the power law scaling of the variation of the minimum neck radius with time, they disagree with respect to the numerical value of the prefactors in the scaling laws. In order to reconcile these differences and also provide insights into the dynamics that are difficult to probe by either of the aforementioned approaches, simulations are used to access both earlier times than has been possible in the experiments and also later times when asymptotic analysis is no longer applicable. Early times and extremely small length scales are attained in the new simulations through the use of a truncated domain approach. Furthermore, it is shown by direct numerical simulations in which the flow within the bubbles is also determined along with the flow exterior to them that idealizing the bubbles as passive voids has virtually no effect on the scaling laws relating minimum neck radius and time.

  12. Financial Bubbles, Real Estate Bubbles, Derivative Bubbles, and the Financial and Economic Crisis

    Science.gov (United States)

    Sornette, Didier; Woodard, Ryan

    The financial crisis of 2008, which started with an initially well-defined epicenter focused on mortgage backed securities (MBS), has been cascading into a global economic recession, whose increasing severity and uncertain duration has led and is continuing to lead to massive losses and damage for billions of people. Heavy central bank interventions and government spending programs have been launched worldwide and especially in the USA and Europe, with the hope to unfreeze credit and bolster consumption. Here, we present evidence and articulate a general framework that allows one to diagnose the fundamental cause of the unfolding financial and economic crisis: the accumulation of several bubbles and their interplay and mutual reinforcement have led to an illusion of a "perpetual money machine" allowing financial institutions to extract wealth from an unsustainable artificial process. Taking stock of this diagnostic, we conclude that many of the interventions to address the so-called liquidity crisis and to encourage more consumption are ill-advised and even dangerous, given that precautionary reserves were not accumulated in the "good times" but that huge liabilities were. The most "interesting" present times constitute unique opportunities but also great challenges, for which we offer a few recommendations.

  13. Pediatric Ocular Trauma

    Science.gov (United States)

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Pediatric Ocular Trauma What causes eye injuries ? Injuries to the ... only the eyelid but the structures that drain tears from the eye. Lacerations of the eyelid or ...

  14. Suspension Trauma / Orthostatic Intolerance

    Science.gov (United States)

    ... Emphasis Programs Directives Severe Violators TOPICS By Sector Construction Health Care Agriculture Maritime Oil and Gas Federal ... such fatalities often are referred to as "harnessinduced pathology" or "suspension trauma." Signs & symptoms that may be ...

  15. Trauma and Coagulation

    Directory of Open Access Journals (Sweden)

    Murat Yılmaz

    2011-08-01

    Full Text Available Bleeding and coagulation disorders related to trauma are pathological processes which are frequently seen and increase mortality. For the purpose, trauma patients should be protected from hypoperfusion, hypothermia, acidosis and hemodilution which may aggravate the increase in physiological responses to trauma as anticoagulation and fibrinolysis. Performing damage control surgery and resuscitation and transfusion of adequate blood and blood products in terms of amount and content as stated in protocols may increase the rate of survival. Medical treatments augmenting fibrin formation (fibrinogen, desmopressin, factor VIIa or preventing fibrin degradation (tranexamic acid have been proposed in selected cases but the efficacy of these agents in trauma patients are not proven. (Journal of the Turkish Society Intensive Care 2011; 9:71-6

  16. About Military Sexual Trauma

    Medline Plus

    Full Text Available ... Search Loading... Close Yeah, keep it Undo Close This video is unavailable. Watch Queue Queue Watch Queue Queue Remove ... Queue Queue __count__/__total__ Find out why Close About Military Sexual Trauma Veterans Health Administration Loading... Unsubscribe ...

  17. Platelet aggregation following trauma

    DEFF Research Database (Denmark)

    Windeløv, Nis A; Sørensen, Anne M; Perner, Anders

    2014-01-01

    We aimed to elucidate platelet function in trauma patients, as it is pivotal for hemostasis yet remains scarcely investigated in this population. We conducted a prospective observational study of platelet aggregation capacity in 213 adult trauma patients on admission to an emergency department (ED......). Inclusion criteria were trauma team activation and arterial cannula insertion on arrival. Blood samples were analyzed by multiple electrode aggregometry initiated by thrombin receptor agonist peptide 6 (TRAP) or collagen using a Multiplate device. Blood was sampled median 65 min after injury; median injury...... severity score (ISS) was 17; 14 (7%) patients received 10 or more units of red blood cells in the ED (massive transfusion); 24 (11%) patients died within 28 days of trauma: 17 due to cerebral injuries, four due to exsanguination, and three from other causes. No significant association was found between...

  18. Acute coagulopathy of trauma

    DEFF Research Database (Denmark)

    Johansson, P I; Ostrowski, S R

    2010-01-01

    Acute coagulopathy of trauma predicts a poor clinical outcome. Tissue trauma activates the sympathoadrenal system resulting in high circulating levels of catecholamines that influence hemostasis dose-dependently through immediate effects on the two major compartments of hemostasis, i.......e., the circulating blood and the vascular endothelium. There appears to be a dose-dependency with regards to injury severity and the hemostatic response to trauma evaluated in whole blood by viscoelastic assays like thrombelastography (TEG), changing from normal to hypercoagulable, to hypocoagulable and finally......, is an evolutionary developed response that counterbalances the injury and catecholamine induced endothelial activation and damage. Given this, the rise in circulating catecholamines in trauma patients may favor a switch from hyper- to hypocoagulability in the blood to keep the progressively more procoagulant...

  19. Common Reactions After Trauma

    Science.gov (United States)

    ... Guide Purpose and Scope Find Assessment Measures Instrument Authority List Research and Biology Research on PTSD Biology ... Mental Health Mental Health Home Suicide Prevention Substance Abuse Military Sexual Trauma PTSD Research (MIRECC) Military Exposures ...

  20. Blunt trauma in pregnancy.

    Science.gov (United States)

    Grossman, Nancy Beth

    2004-10-01

    Trauma is the most common cause of nonobstetric death among pregnant women in the United States. Motor vehicle crashes, domestic violence, and falls are the most common causes of blunt trauma during pregnancy. All pregnant patients with traumatic injury should be assessed formally in a medical setting because placental abruption can have dire fetal consequences and can present with few or no symptoms. Evaluation and treatment are the same as for nonpregnant patients, except that the uterus should be shifted off the great vessels. After initial stabilization, management includes electronic fetal monitoring, ultrasonography, and laboratory studies. Electronic fetal monitoring currently is the most accurate measure of fetal status after trauma, although the optimal duration of monitoring has not been established. Prevention of trauma through proper seat belt use during pregnancy and recognition of domestic violence during prenatal care is important.

  1. Obesity in pediatric trauma.

    Science.gov (United States)

    Witt, Cordelie E; Arbabi, Saman; Nathens, Avery B; Vavilala, Monica S; Rivara, Frederick P

    2017-04-01

    The implications of childhood obesity on pediatric trauma outcomes are not clearly established. Anthropomorphic data were recently added to the National Trauma Data Bank (NTDB) Research Datasets, enabling a large, multicenter evaluation of the effect of obesity on pediatric trauma patients. Children ages 2 to 19years who required hospitalization for traumatic injury were identified in the 2013-2014 NTDB Research Datasets. Age and gender-specific body mass indices (BMI) were calculated. Outcomes included injury patterns, operative procedures, complications, and hospital utilization parameters. Data from 149,817 pediatric patients were analyzed; higher BMI percentiles were associated with significantly more extremity injuries, and fewer injuries to the head, abdomen, thorax and spine (p values trauma, increased BMI percentile is associated with increased risk of death and potentially preventable complications. These findings suggest that obese children may require different management than nonobese counterparts to prevent complications. Level III; prognosis study. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Coagulation complications following trauma.

    Science.gov (United States)

    Martini, Wenjun Z

    2016-01-01

    Traumatic injury is one of the leading causes of death, with uncontrolled hemorrhage from coagulation dysfunction as one of the main potentially preventable causes of the mortality. Hypothermia, acidosis, and resuscitative hemodilution have been considered as the significant contributors to coagulation manifestations following trauma, known as the lethal triad. Over the past decade, clinical observations showed that coagulopathy may be present as early as hospital admission in some severely injured trauma patients. The hemostatic dysfunction is associated with higher blood transfusion requirements, longer hospital stay, and higher mortality. The recognition of this early coagulopathy has initiated tremendous interest and effort in the trauma community to expand our understanding of the underlying pathophysiology and improve clinical treatments. This review discusses the current knowledge of coagulation complications following trauma.

  3. Research of bubble flow characteristics in microfluidic chip

    Science.gov (United States)

    Qiu, Chao; Cheng, Han; Chen, Shuxian

    2017-04-01

    Bubble is the heart of the microfluidic chip, which takes a significant role in drug release, biological detection and so on. In this case, bubble flow characteristics in microfluidic chip are the key to realize its function. In this paper, bubble flow characteristics in the microfluidic chip have been studied with high speed photography system by controlling the wettability and the heat flux of the microelectrode surface. The result shows that bubble flows faster on the electrode with hydrophobic surface. In addition, loading current to the electrode with hydrophilic surface could also speed up the movement of bubble, and the flow rate of bubble increases with the increasing heat flux of the electrode.

  4. Herds of methane chambers grazing bubbles

    Science.gov (United States)

    Grinham, Alistair; Dunbabin, Matthew

    2014-05-01

    Water to air methane emissions from freshwater reservoirs can be dominated by sediment bubbling (ebullitive) events. Previous work to quantify methane bubbling from a number of Australian sub-tropical reservoirs has shown that this can contribute as much as 95% of total emissions. These bubbling events are controlled by a variety of different factors including water depth, surface and internal waves, wind seiching, atmospheric pressure changes and water levels changes. Key to quantifying the magnitude of this emission pathway is estimating both the bubbling rate as well as the areal extent of bubbling. Both bubbling rate and areal extent are seldom constant and require persistent monitoring over extended time periods before true estimates can be generated. In this paper we present a novel system for persistent monitoring of both bubbling rate and areal extent using multiple robotic surface chambers and adaptive sampling (grazing) algorithms to automate the quantification process. Individual chambers are self-propelled and guided and communicate between each other without the need for supervised control. They can maintain station at a sampling site for a desired incubation period and continuously monitor, record and report fluxes during the incubation. To exploit the methane sensor detection capabilities, the chamber can be automatically lowered to decrease the head-space and increase concentration. The grazing algorithms assign a hierarchical order to chambers within a preselected zone. Chambers then converge on the individual recording the highest 15 minute bubbling rate. Individuals maintain a specified distance apart from each other during each sampling period before all individuals are then required to move to different locations based on a sampling algorithm (systematic or adaptive) exploiting prior measurements. This system has been field tested on a large-scale subtropical reservoir, Little Nerang Dam, and over monthly timescales. Using this technique

  5. Blunt chest trauma.

    Science.gov (United States)

    Stewart, Daphne J

    2014-01-01

    Blunt chest trauma is associated with a wide range of injuries, many of which are life threatening. This article is a case study demonstrating a variety of traumatic chest injuries, including pathophysiology, diagnosis, and treatment. Literature on the diagnosis and treatment was reviewed, including both theoretical and research literature, from a variety of disciplines. The role of the advance practice nurse in trauma is also discussed as it relates to assessment, diagnosis, and treatment of patients with traumatic chest injuries.

  6. London Trauma Conference 2015

    OpenAIRE

    Avery, Pascale; Salm, Leopold; Bird, Flora; Hutchinson, Anja; Jarman, Heather; Nilsson, Maria Bergman; Konig, Tom; Tai, Nigel; Fevang, Espen; Hognestad, B?rge; Abrahamsen, H?kon B.; Cheetham, Olivia V.; Thomas, Matthew J. C.; Rooney, Kieron D.; Murray, Josephine

    2016-01-01

    Table of contents I1: Trauma, Pre-hospital and Cardiac Arrest Care 2015 Pascale Avery, Leopold Salm, Flora Bird A1: Retrospective evaluation of HEMS ?Direct to CT? protocol Anja Hutchinson, Ashley Matthies, Anthony Hudson, Heather Jarman A2 Rush hour ? Crush hour: temporal relationship of cyclist vs. HGV trauma admissions. A single site observational study Maria Bergman Nilsson, Tom Konig, Nigel Tai A3 Semiprone position endotracheal intubation during continuous cardiopulmonary resuscitation ...

  7. Quality of trauma care and trauma registries.

    Science.gov (United States)

    Pino Sánchez, F I; Ballesteros Sanz, M A; Cordero Lorenzana, L; Guerrero López, F

    2015-03-01

    Traumatic disease is a major public health concern. Monitoring the quality of services provided is essential for the maintenance and improvement thereof. Assessing and monitoring the quality of care in trauma patient through quality indicators would allow identifying opportunities for improvement whose implementation would improve outcomes in hospital mortality, functional outcomes and quality of life of survivors. Many quality indicators have been used in this condition, although very few ones have a solid level of scientific evidence to recommend their routine use. The information contained in the trauma registries, spread around the world in recent decades, is essential to know the current health care reality, identify opportunities for improvement and contribute to the clinical and epidemiological research. Copyright © 2014 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

  8. The stability of large oscillating bubbles

    Science.gov (United States)

    Blake, John; Pearson, Antony

    2002-11-01

    In a most remarkable paper, in October 1942, Penney & Price developed a theory for the stability of large oscillating bubbles; in their case they were interested in underwater explosions. Much of our current understanding on the stability of oscillating bubbles can be traced to the theoretical and experimental insight shown in this paper. While interest in this particular area continues with regard ship survivability to underwater explosions, other newer areas include the oscillatory behaviour of of seismic airgun generated bubbles. Apart from large volume oscillations with a characteristic period, the other dominant parameter is associated with buoyancy. An appropriate parameter is chosen that provides a measure of the distance of migration of a bubble over one period. An analytical and computational analysis of this class of problem reveals that this pressure gradient driven instability, normally observed in the form of a high speed liquid jet threading the bubble, is the most dominant surface instability, a characteristic feature borne out in most experimental and practical applications due to the presence of an incipient pressure gradient associated with hydrostatics, dynamics or boundaries

  9. Argonne Bubble Experiment Thermal Model Development III

    Energy Technology Data Exchange (ETDEWEB)

    Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2018-01-11

    This report describes the continuation of the work reported in “Argonne Bubble Experiment Thermal Model Development” and “Argonne Bubble Experiment Thermal Model Development II”. The experiment was performed at Argonne National Laboratory (ANL) in 2014. A rastered 35 MeV electron beam deposited power in a solution of uranyl sulfate, generating heat and radiolytic gas bubbles. Irradiations were performed at beam power levels between 6 and 15 kW. Solution temperatures were measured by thermocouples, and gas bubble behavior was recorded. The previous report2 described the Monte-Carlo N-Particle (MCNP) calculations and Computational Fluid Dynamics (CFD) analysis performed on the as-built solution vessel geometry. The CFD simulations in the current analysis were performed using Ansys Fluent, Ver. 17.2. The same power profiles determined from MCNP calculations in earlier work were used for the 12 and 15 kW simulations. The primary goal of the current work is to calculate the temperature profiles for the 12 and 15 kW cases using reasonable estimates for the gas generation rate, based on images of the bubbles recorded during the irradiations. Temperature profiles resulting from the CFD calculations are compared to experimental measurements.

  10. Drop impact entrapment of bubble rings

    KAUST Repository

    Thoraval, M.-J.

    2013-04-29

    We use ultra-high-speed video imaging to look at the initial contact of a drop impacting on a liquid layer. We observe experimentally the vortex street and the bubble-ring entrapments predicted numerically, for high impact velocities, by Thoraval et al. (Phys. Rev. Lett., vol. 108, 2012, article 264506). These dynamics mainly occur within 50 -s after the first contact, requiring imaging at 1 million f.p.s. For a water drop impacting on a thin layer of water, the entrapment of isolated bubbles starts through azimuthal instability, which forms at low impact velocities, in the neck connecting the drop and pool. For Reynolds number Re above -12 000, up to 10 partial bubble rings have been observed at the base of the ejecta, starting when the contact is -20% of the drop size. More regular bubble rings are observed for a pool of ethanol or methanol. The video imaging shows rotation around some of these air cylinders, which can temporarily delay their breakup into micro-bubbles. The different refractive index in the pool liquid reveals the destabilization of the vortices and the formation of streamwise vortices and intricate vortex tangles. Fine-scale axisymmetry is thereby destroyed. We show also that the shape of the drop has a strong influence on these dynamics. 2013 Cambridge University Press.

  11. The Quest for the Most Spherical Bubble

    CERN Document Server

    Obreschkow, Danail; Dorsaz, Nicolas; Kobel, Philippe; de Bosset, Aurele; Farhat, Mohamed

    2013-01-01

    We describe a recently realized experiment producing the most spherical cavitation bubbles today. The bubbles grow inside a liquid from a point-plasma generated by a nanosecond laser pulse. Unlike in previous studies, the laser is focussed by a parabolic mirror, resulting in a plasma of unprecedented symmetry. The ensuing bubbles are sufficiently spherical that the hydrostatic pressure gradient caused by gravity becomes the dominant source of asymmetry in the collapse and rebound of the cavitation bubbles. To avoid this natural source of asymmetry, the whole experiment is therefore performed in microgravity conditions (ESA, 53rd and 56th parabolic flight campaign). Cavitation bubbles were observed in microgravity (~0g), where their collapse and rebound remain spherical, and in normal gravity (1g) to hyper-gravity (1.8g), where a gravity-driven jet appears. Here, we describe the experimental setup and technical results, and overview the science data. A selection of high-quality shadowgraphy movies and time-res...

  12. Bubble growth in a narrow horizontal space

    Energy Technology Data Exchange (ETDEWEB)

    Stutz, Benoit; Goulet, Remi [CETHIL, UMR5008, CNRS, INSA-Lyon, Universite Lyon1 (France); Passos, Julio Cesar [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. LABSOLAR

    2009-07-01

    The purpose of this work is to develop an axis-symmetric two-phase flow model describing the growth of a single bubble squeezed between a horizontal heated upward-facing disc and an insulating surface placed parallel to the heated surface. Heat transfers at the liquid-vapour interfaces are predicted by the kinetic limit of vaporisation. The depths of the liquid films deposed on the surfaces (heated surface and confinement space) are determined using the Moriyama and Inoue correlation (1996). Transient heat transfers within the heated wall are taken into account. The model is applied to pentane bubble growth. The influence of the gap size, the initial temperature of the system, the thermal effusivity of the heated wall and the kinetic limit of vaporisation are studied. The results show that the expansion of the bubbles strongly depends on the gap size and can be affected by the effusivity of the material. Mechanical inertia effects are mainly dominant at the beginning of the bubble expansion. Pressure drop induced by viscous effects have to be taken into account for high capillary numbers. Heat transfers at the meniscus are negligible except at the early stages of the bubble growth. (author)

  13. Tribology of thin wetting films between bubble and moving solid surface.

    Science.gov (United States)

    Karakashev, Stoyan I; Stöckelhuber, Klaus W; Tsekov, Roumen; Phan, Chi M; Heinrich, Gert

    2014-08-01

    This work shows a successful example of coupling of theory and experiment to study the tribology of bubble rubbing on solid surface. Such kind of investigation is reported for the first time in the literature. A theory about wetting film intercalated between bubble and moving solid surface was developed, thus deriving the non-linear evolution differential equation which accounted for the friction slip coefficient at the solid surface. The stationary 3D film thickness profile, which appears to be a solution of the differential equation, for each particular speed of motion of the solid surface was derived by means of special procedure and unique interferometric experimental setup. This allowed us to determine the 3D map of the lift pressure within the wetting film, the friction force per unit area and the friction coefficient of rubbing at different speeds of motion of the solid surface. Thus, we observed interesting tribological details about the rubbing of the bubble on the solid surface like for example: 1. A regime of mixed friction between dry and lubricated friction exists in the range of 6-170 μm/s, beyond which the rubbing between the bubble and solid becomes completely lubricated and passes through the maximum; 2. The friction coefficient of rubbing has high values at very small speeds of solid's motion and reduces substantially with the increase of the speed of the solid motion until reaching small values, which change insignificantly with the further increase of the speed of the solid. Despite the numerous studies on the motion of bubble/droplet in close proximity to solid wall in the literature, the present investigation appears to be a step ahead in this area as far as we were able to derive 3D maps of the bubble close to the solid surface, which makes the investigation more profound. © 2013.

  14. Hypothermia in trauma.

    Science.gov (United States)

    Moffatt, Samuel Edwin

    2013-12-01

    Hypovolaemic shock that results through traumatically inflicted haemorrhage can have disastrous consequences for the victim. Initially the body can compensate for lost circulating volume, but as haemorrhage continues compensatory mechanisms fail and the patient's condition worsens significantly. Hypovolaemia results in the lethal triad, a combination of hypothermia, acidosis and coagulopathy, three factors that are interlinked and serve to worsen each other. The lethal triad is a form of vicious cycle, which unless broken will result in death. This report will focus on the role of hypothermia (a third of the lethal triad) in trauma, examining literature to assess how prehospital temperature control can impact on the trauma patient. Spontaneous hypothermia following trauma has severely deleterious consequences for the trauma victim; however, both active warming of patients and clinically induced hypothermia can produce particularly positive results and improve patient outcome. Possible coagulopathic side effects of clinically induced hypothermia may be corrected with topical haemostatic agents, with the benefits of an extended golden hour given by clinically induced hypothermia far outweighing these risks. Active warming of patients, to prevent spontaneous trauma induced hypothermia, is currently the only viable method currently available to improve patient outcome. This method is easy to implement requiring simple protocols and contributes significantly to interrupting the lethal triad. However, the future of trauma care appears to lie with clinically induced therapeutic hypothermia. This new treatment provides optimism that in the future the number of deaths resulting from catastrophic haemorrhaging may be significantly lessened.

  15. Trauma social y memoria colectiva

    Directory of Open Access Journals (Sweden)

    Margarita Iglesias Saldaña

    2009-04-01

    Full Text Available El trauma social y la memoria colectiva, o memorias colectivas están de la mano en la América latina post-dictatorial. Desde fines de los años ochenta, se fueron destituyendo las dictaduras latinoamericanas, la mayoría sobre bases de consensos entre las fuerzas dictatoriales y los negociadores políticos de corrientes democráticas. La fuerza de los movimientos sociales sirvió de puente para las negociaciones, pero no logró estar del todo en las transacciones hacia los procesos de transición. Si así hubiera sido, la justicia y la verdad hubieran tenido un lugar privilegiado en los procesos denominados de "transición a las democracias" en distintos países del cono sur latinoamericano. La memoria colectiva ligada al trauma social tendrá varios componentes que abarcan también la memoria individual, incluyendo los espacios de la experiencia, propia y ajena. Este artículo pretende bucear en las interacciones entre ambos ámbitos de la memoria y sus conexiones con el tiempo presente.__________ABSTRACT:Social trauma and collective memory or collective memories are linked to the post-dictatorial Latin America. Since the late eighties, Latin American dictatorships were progressively dismissing, the majority on the basis of consensus between the dictatorial forces and the political mediators of the democratic part. The strength of social movements formed the bridge to negotiations, but could not entirely participate in the transactions to the transition process. If it would have been so, justice and truth would have had a special place in the process called "transition to democracy" in several Latin American Southern Cone countries. The collective memory linked to social trauma will have several components that also include individual memory, including personal and collective spaces of experience. This article aims to analyze the interactions between the two areas of memory and its connections to the present time.

  16. Near-wall measurements of the bubble- and Lorentz-force-driven convection at gas-evolving electrodes

    Science.gov (United States)

    Baczyzmalski, Dominik; Weier, Tom; Kähler, Christian J.; Cierpka, Christian

    2015-08-01

    Chemical energy storage systems, e.g., in the form of hydrogen or methanol, have a great potential for the establishment of volatile renewable energy sources due to the large energy density. The efficiency of hydrogen production through water electrolysis is, however, limited by gas bubbles evolving at the electrode's surface and can be enhanced by an accelerated bubble detachment. In order to characterize the complex multi-phase flow near the electrode, simultaneous measurements of the fluid velocities and the size and trajectories of hydrogen bubbles were performed in a water electrolyzer. The liquid phase velocity was measured by PIV/PTV, while shadowgraphy was used to determine the bubble trajectories. Special measurement and evaluation techniques had to be applied as the measurement uncertainty is strongly affected by the high void fraction close to the wall. In particular, the application of an advanced PTV scheme allowed for more precise fluid velocity measurements closer to electrode. Based on these data, stability characteristics of the near-wall flow were evaluated and compared to that of a wall jet. PTV was used as well to investigate the effect of Lorentz forces on the near-wall fluid velocities. The results show a significantly increased wall parallel liquid phase velocity with increasing Lorentz forces. It is presumed that this enhances the detachment of hydrogen bubbles from the electrode surface and, consequently, decreases the fractional bubble coverage and improves the efficiency. In addition, the effect of large rising bubbles with path oscillations on the near-wall flow was investigated. These bubbles can have a strong impact on the mass transfer near the electrode and thus affect the performance of the process.

  17. High energy neutrinos from the Fermi bubbles.

    Science.gov (United States)

    Lunardini, Cecilia; Razzaque, Soebur

    2012-06-01

    Recently the Fermi-LAT data have revealed two gamma-ray emitting bubble-shaped structures at the Galactic center. If the observed gamma rays have hadronic origin (collisions of accelerated protons), the bubbles must emit high energy neutrinos as well. This new, Galactic, neutrino flux should trace the gamma-ray emission in spectrum and spatial extent. Its highest energy part, above 20-50 TeV, is observable at a kilometer-scale detector in the northern hemisphere, such as the planned KM3NeT, while interesting constraints on it could be obtained by the IceCube Neutrino Observatory at the South Pole. The detection or exclusion of neutrinos from the Fermi bubbles will discriminate between hadronic and leptonic models, thus bringing unique information on the still mysterious origin of these objects and on the time scale of their formation.

  18. Root Causes of the Housing Bubble

    Science.gov (United States)

    Kaizoji, Taisei

    In this chapter we investigate root causes of the recent US housing bubble which has been caused a serious downturn in US economic growth since autumn of 2008. We propose a simple model of housing markets in order to indicate the possible determinants of recent housing prices. Utilizing the model, we verify a number of hypotheses which have been proposed in the recent literature on the housing bubbles. We suggest that the main causes of the housing bubble from 2000 to 2006 are (1) non-elastic housing supply in the metropolitan areas, and (2) declines in the mortgage loan rate and the housing premium by the massive mortgage credit expansion. We also suggest that these factors were strongly influenced by policies that governments and the Federal Reserve Board performed.

  19. Toward a Metatheory of Economic Bubbles

    DEFF Research Database (Denmark)

    Dholakia, Nikhilesh; Turcan, Romeo V.

    Dholakia and Turcan present their interdisciplinary metatheory of bubbles with short case studies of minor and major bubbles. They comprehensively identify and exemplify constructs of the theory, set its temporal and contextual boundaries, and examine the underlying economic, psychological......, and social dynamics assumptions, explaining how these elements are related. By doing so, they provide a partial window into the precarious nature of contemporary finance-driven capitalism and suggest some possible ways of overcoming the wrenching ups and downs of the prevalent system. The case studies...... and original research in Toward a Metatheory of Economic Bubbles have far-reaching implications for the study and practice of entrepreneurship and marketing, public and corporate finance, and public policies towards innovation, economy, and finance. It contributes to the defining issues for economic sociology...

  20. Rational speculative bubbles: A critical view

    Directory of Open Access Journals (Sweden)

    Radonjić Ognjen

    2007-01-01

    Full Text Available According to the theory of rational bubbles, the bubble is present whenever asset prices progressively diverge from their fundamental value, which occurs because agents expect that asset prices will continue to grow exponentially (self-fulfilling prophecies far in the future and consistently, which promises the realization of ever larger capital gains. In our opinion, the basic shortcoming of this theory refers to the assumption that all market agents are perfectly informed and rational and, accordingly, form homogeneous expectations. The model does not explain decision-making processes or expectation formation, nor does it detect potential psychological and institutional factors that might significantly influence decision making processes and market participants’ reactions to news. Since assumptions of the model critically determine its validity, we conclude that comprehensiveness of the rational bubble model is, to put it mildly, limited.

  1. Bubbles, shocks and elementary technical trading strategies

    Science.gov (United States)

    Fry, John

    2014-01-01

    In this paper we provide a unifying framework for a set of seemingly disparate models for bubbles, shocks and elementary technical trading strategies in financial markets. Markets operate by balancing intrinsic levels of risk and return. This seemingly simple observation is commonly over-looked by academics and practitioners alike. Our model shares its origins in statistical physics with others. However, under our approach, changes in market regime can be explicitly shown to represent a phase transition from random to deterministic behaviour in prices. This structure leads to an improved physical and econometric model. We develop models for bubbles, shocks and elementary technical trading strategies. The list of empirical applications is both interesting and topical and includes real-estate bubbles and the on-going Eurozone crisis. We close by comparing the results of our model with purely qualitative findings from the finance literature.

  2. Topological vacuum bubbles by anyon braiding.

    Science.gov (United States)

    Han, Cheolhee; Park, Jinhong; Gefen, Yuval; Sim, H-S

    2016-03-31

    According to a basic rule of fermionic and bosonic many-body physics, known as the linked cluster theorem, physical observables are not affected by vacuum bubbles, which represent virtual particles created from vacuum and self-annihilating without interacting with real particles. Here we show that this conventional knowledge must be revised for anyons, quasiparticles that obey fractional exchange statistics intermediate between fermions and bosons. We find that a certain class of vacuum bubbles of Abelian anyons does affect physical observables. They represent virtually excited anyons that wind around real anyonic excitations. These topological bubbles result in a temperature-dependent phase shift of Fabry-Perot interference patterns in the fractional quantum Hall regime accessible in current experiments, thus providing a tool for direct and unambiguous observation of elusive fractional statistics.

  3. Moving with bubbles: a review of the interactions between bubbles and the microorganisms that surround them.

    Science.gov (United States)

    Walls, Peter L L; Bird, James C; Bourouiba, Lydia

    2014-12-01

    Bubbles are ubiquitous in biological environments, emerging during the complex dynamics of waves breaking in the open oceans or being intentionally formed in bioreactors. From formation, through motion, until death, bubbles play a critical role in the oxygenation and mixing of natural and artificial ecosystems. However, their life is also greatly influenced by the environments in which they emerge. This interaction between bubbles and microorganisms is a subtle affair in which surface tension plays a critical role. Indeed, it shapes the role of bubbles in mixing or oxygenating microorganisms, but also determines how microorganisms affect every stage of the bubble's life. In this review, we guide the reader through the life of a bubble from birth to death, with particular attention to the microorganism-bubble interaction as viewed through the lens of fluid dynamics. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  4. "Bubble-on-demand" generator with precise adsorption time control.

    Science.gov (United States)

    Zawala, J; Niecikowska, A

    2017-09-01

    The paper presents the principles of our new single bubble generator, which allows a precise control of bubble formation in pure liquids and surfactant solutions, i.e., their detachment frequency and the adsorption time at their motionless surface. We show that the bubbles with equilibrium size can be produced at the capillaries of various orifice diameters (0.022-0.128 mm) on demand and with outstanding reproducibility. Moreover, it is shown that a fully automatized and programmable bubble trap, synchronized with bubble detachment frequency, can be used to (i) control the radius of the released bubble and (ii) precisely adjust the initial adsorption coverage over the surface of detaching bubble, and hence to study the influence of adsorption coverage degree on kinetics of dynamic adsorption layer formation at the rising bubble surface.

  5. Simulations of Bubble Motion in an Oscillating Liquid

    Science.gov (United States)

    Kraynik, A. M.; Romero, L. A.; Torczynski, J. R.

    2010-11-01

    Finite-element simulations are used to investigate the motion of a gas bubble in a liquid undergoing vertical vibration. The effect of bubble compressibility is studied by comparing "compressible" bubbles that obey the ideal gas law with "incompressible" bubbles that are taken to have constant volume. Compressible bubbles exhibit a net downward motion away from the free surface that does not exist for incompressible bubbles. Net (rectified) velocities are extracted from the simulations and compared with theoretical predictions. The dependence of the rectified velocity on ambient gas pressure, bubble diameter, and bubble depth are in agreement with the theory. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  6. "Bubble-on-demand" generator with precise adsorption time control

    Science.gov (United States)

    Zawala, J.; Niecikowska, A.

    2017-09-01

    The paper presents the principles of our new single bubble generator, which allows a precise control of bubble formation in pure liquids and surfactant solutions, i.e., their detachment frequency and the adsorption time at their motionless surface. We show that the bubbles with equilibrium size can be produced at the capillaries of various orifice diameters (0.022-0.128 mm) on demand and with outstanding reproducibility. Moreover, it is shown that a fully automatized and programmable bubble trap, synchronized with bubble detachment frequency, can be used to (i) control the radius of the released bubble and (ii) precisely adjust the initial adsorption coverage over the surface of detaching bubble, and hence to study the influence of adsorption coverage degree on kinetics of dynamic adsorption layer formation at the rising bubble surface.

  7. Cavitation Bubble Dynamics in Ammoniacal Fluids Transferred by Centrifugal Pumps

    Directory of Open Access Journals (Sweden)

    Jorge Reyes-Cruz

    2016-10-01

    Full Text Available An experiment with water and ammoniacal liquor at 27% and 34% concentrations of ammonia was carried out in order to determine the pressure dynamics during the formation of bubbles and their movement when causing cavitations in centrifugal pumps. The dynamics of bubbles was calculated numerically by applying the Rayleigh-Plesset equation using the bubble radius and the bubble build-up time. It is concluded that the pressure to form the bubbles at 22 ºC is 10,135.103 Pa for water and 45,468.103 Pa for the ammoniacal liquor at a concentration of 34 %. The radius of the bubbles found in ammoniacal liquor is in the range of 30 to 120 times the original bubble radius while the bubbles formed in water are only in the range of 15 times the original radius value.

  8. Bubble Dynamics in a Two-Phase Medium

    CERN Document Server

    Jayaprakash, Arvind; Chahine, Georges

    2010-01-01

    The spherical dynamics of a bubble in a compressible liquid has been studied extensively since the early work of Gilmore. Numerical codes to study the behavior, including when large non-spherical deformations are involved, have since been developed and have been shown to be accurate. The situation is however different and common knowledge less advanced when the compressibility of the medium surrounding the bubble is provided mainly by the presence of a bubbly mixture. In one of the present works being carried out at DYNAFLOW, INC., the dynamics of a primary relatively large bubble in a water mixture including very fine bubbles is being investigated experimentally and the results are being provided to several parallel on-going analytical and numerical approaches. The main/primary bubble is produced by an underwater spark discharge from two concentric electrodes placed in the bubbly medium, which is generated using electrolysis. A grid of thin perpendicular wires is used to generate bubble distributions of vary...

  9. A note on effects of rational bubble on portfolios

    Science.gov (United States)

    Wang, Chan; Nie, Pu-yan

    2018-02-01

    In general, demand increases in wealth and decreases in price in microeconomics. We thereby propose a completely different perspective. By establishing expected utility function of investors, this article introduces one rational bubble asset and one bubble free asset in portfolios and focuses on the effects of bubble on investment portfolios from wealth and price perspectives. All conclusions are obtained by theoretical analysis with microeconomics theory. We argue that inferior goods and Giffen behavior can occur for the bubble free asset in microeconomic fields. The results can help investors to recognize bubble assets and bubble free assets more scientifically. Both bubble and bubble free assets can be inferior goods under some conditions, so we cannot to say which asset better than the other one absolutely.

  10. Surface magnetostatic oscillations in elliptical bubble domains

    Science.gov (United States)

    Popov, M. A.; Zavislyak, I. V.

    2009-01-01

    A theory of surface magnetostatic oscillations in magnetic bubble domains with an elliptical cross section is presented. The dependences of the eigenfrequencies of resonant modes on the applied magnetic field are analyzed for a barium hexaferrite sample with allowance made for the change in the domain size due to a variation in the bias magnetic field. The range of frequency tuning in response to a magnetic field ranging from the elliptical instability field to the collapse field is estimated. It is demonstrated that elliptical bubble domains can be used as microminiature resonators operating in the millimeter range.

  11. Partial coalescence from bubbles to drops

    KAUST Repository

    Zhang, F. H.

    2015-10-07

    The coalescence of drops is a fundamental process in the coarsening of emulsions. However, counter-intuitively, this coalescence process can produce a satellite, approximately half the size of the original drop, which is detrimental to the overall coarsening. This also occurs during the coalescence of bubbles, while the resulting satellite is much smaller, approximately 10 %. To understand this difference, we have conducted a set of coalescence experiments using xenon bubbles inside a pressure chamber, where we can continuously raise the pressure from 1 up to 85 atm and thereby vary the density ratio between the inner and outer fluid, from 0.005 up to unity. Using high-speed video imaging, we observe a continuous increase in satellite size as the inner density is varied from the bubble to emulsion-droplet conditions, with the most rapid changes occurring as the bubble density grows up to 15 % of that of the surrounding liquid. We propose a model that successfully relates the satellite size to the capillary wave mode responsible for its pinch-off and the overall deformations from the drainage. The wavelength of the primary wave changes during its travel to the apex, with the instantaneous speed adjusting to the local wavelength. By estimating the travel time of this wave mode on the bubble surface, we also show that the model is consistent with the experiments. This wavenumber is determined by both the global drainage as well as the interface shapes during the rapid coalescence in the neck connecting the two drops or bubbles. The rate of drainage is shown to scale with the density of the inner fluid. Empirically, we find that the pinch-off occurs when 60 % of the bubble fluid has drained from it. Numerical simulations using the volume-of-fluid method with dynamic adaptive grid refinement can reproduce these dynamics, as well as show the associated vortical structure and stirring of the coalescing fluid masses. Enhanced stirring is observed for cases with second

  12. Impact of money supply on stock bubbles

    Directory of Open Access Journals (Sweden)

    Martin Širůček

    2013-01-01

    Full Text Available This article focuses on the effect and implications of changes in money supply in the US on stock bubble rise on the US capital market, which is represented by the Dow Jones Industrial Average index. This market was chosen according to the market capitalization. The attention of the paper is drawn to issues – if according to the results of empirical analysis, the money supply is a significant factor which causes the bubbles and if during the time the significance and impact of this macroeconomic factor on stock index increase.

  13. On the maximum drawdown during speculative bubbles

    Science.gov (United States)

    Rotundo, Giulia; Navarra, Mauro

    2007-08-01

    A taxonomy of large financial crashes proposed in the literature locates the burst of speculative bubbles due to endogenous causes in the framework of extreme stock market crashes, defined as falls of market prices that are outlier with respect to the bulk of drawdown price movement distribution. This paper goes on deeper in the analysis providing a further characterization of the rising part of such selected bubbles through the examination of drawdown and maximum drawdown movement of indices prices. The analysis of drawdown duration is also performed and it is the core of the risk measure estimated here.

  14. Stochastic modelling for financial bubbles and policy

    Directory of Open Access Journals (Sweden)

    John Fry

    2015-12-01

    Full Text Available In this paper, we draw upon the close relationship between statistical physics and mathematical finance to develop a suite of models for financial bubbles and crashes. By modifying previous approaches, we are able to derive novel analytical formulae for evaluation problems and for the expected timing of future change points. In particular, we help to explain why previous approaches have systematically overstated the timing of changes in market regime. The list of potential empirical applications is deep and wide ranging, and includes contemporary housing bubbles, the Eurozone crisis and the Crash of 2008.

  15. Intraalveolar bubbles and bubble films: III. Vulnerability and preservation in the laboratory.

    Science.gov (United States)

    Scarpelli, E M; Mautone, A J; Chinoy, M R; Defouw, D O; Clutario, B C

    1997-08-01

    Having confirmed (Scarpelli et al. 1996. Anat. Rec. 244:344-357 and 246:245-270) the discovery of intraalveolar bubbles and films as the normal anatomical infrastructure of aerated alveoli at all ages, we now address three questions. Why have these structures been so elusive? Visible in fresh lungs from the in vivo state, can they be preserved by known laboratory methods? Can they be preserved intact for study in tissue sections? Lungs of adult rabbits and pups were examined in thorax directly from the in vivo state to confirm normal bubbles both at functional residual capacity and at maximal volume; other lungs were permitted to deflate naturally to minimal volume. The fate of bubbles in situ (either intact, transected, or diced lung tissue) and of isolated bubbles was assessed (1) during conventional histopreparative processing, (2) during inflation-deflation after degassing, (3) after drying in air, (4) during and after quick freezing in liquid N2, and (5) after preservation in fixed and stained tissue sections prepared by a new double-impregnation procedure in which glutaraldehyde-fixed tissue was preembedded in agar, dehydrated and clarified chemically, embedded in paraffin, sectioned, and stained. Control studies included both blocking of bubble formation by rinsing the air spaces with Tween 20 prior to double impregnation and preparation of normal tissue without preembedding in agar. (1) Each of the following procedures in conventional processing dislocated and disrupted bubbles and films: osmium tetroxide and glutaraldehyde:formaldehyde:tannic acid mixture fixation; chemical dehydration (70-100% ethanol) and clarification (xylene and acetone); and embedding in paraffin or epoxy resin. Transection and dicing of the tissue aggravated the untoward effects. In contrast, bubbles and films remained stable in either glutaraldehyde or formaldehyde, which, however, did not protect against the other agents. (2) Degassing destroyed all bubbles as expected; however

  16. Microstructure, morphology and lifetime of armored bubbles exposed to surfactants

    OpenAIRE

    Subramaniam, Anand Bala; Mejean, Cecile; Abkarian, Manouk; Stone, Howard A.

    2006-01-01

    We report the behavior of particle-stabilized bubbles (armored bubbles) when exposed to various classes and concentrations of surfactants. The bubbles are non-spherical due to the jamming of the particles on the interface and are stable to dissolution prior to the addition of surfactant. We find that the dissolving bubbles exhibit distinct morphological, microstructural, and lifetime changes, which correlate with the concentration of surfactant employed. For low concentrations of surfactant a...

  17. Measurement of Entrained Air Bubbles and Vortices in Breaking Waves

    OpenAIRE

    大塚, 淳一; 渡部, 靖憲; Junichi, Otsuka; Yasunori, Watanabe; 北海道大学大学院工学研究科; School of Engineering, Hokkaido University

    2007-01-01

    Breaking waves produce numbers of vortices through a jet splashing process and also entrain many air bubbles, forming complicated air-water two-phase turbulent flow field in a surf zone. In this research, a simultaneous velocity measurement technique of water and bubble flows in breaking waves is developed for characterizing water-bubble interactions within vortices in a surf zone. The bubbles and neutral buoyant tracers are separately recorded by two different digital video cameras on the ba...

  18. A COINTEGRATION TEST TO VERIFY THE HOUSING BUBBLE

    OpenAIRE

    Bala Arshanapalli; William Nelson

    2008-01-01

    Housing prices in the US rose rapidly from 2000-2007Q3. Based on this evidence, the financial and general press concluded the US experienced a housing bubble. The efficient market theory denies the possibility of a bubble. This paper applies the statistical technique of cointegration to substantiate the presence of a housing bubble. The paper finds the statistical evidence consistent with the presence of a housing bubble in the period 2000-2007Q3 and not the underlying economic conditions.

  19. Epidemiology of severe trauma.

    Science.gov (United States)

    Alberdi, F; García, I; Atutxa, L; Zabarte, M

    2014-12-01

    Major injury is the sixth leading cause of death worldwide. Among those under 35 years of age, it is the leading cause of death and disability. Traffic accidents alone are the main cause, fundamentally in low- and middle-income countries. Patients over 65 years of age are an increasingly affected group. For similar levels of injury, these patients have twice the mortality rate of young individuals, due to the existence of important comorbidities and associated treatments, and are more likely to die of medical complications late during hospital admission. No worldwide, standardized definitions exist for documenting, reporting and comparing data on severely injured trauma patients. The most common trauma scores are the Abbreviated Injury Scale (AIS), the Injury Severity Score (ISS) and the Trauma and Injury severity Score (TRISS). Documenting the burden of injury also requires evaluation of the impact of post-trauma impairments, disabilities and handicaps. Trauma epidemiology helps define health service and research priorities, contributes to identify disadvantaged groups, and also facilitates the elaboration of comparable measures for outcome predictions. Copyright © 2014 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.

  20. Male genital trauma

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, G.H.; Gilbert, D.A.

    1988-07-01

    We have attempted to discuss genital trauma in relatively broad terms. In most cases, patients present with relatively minimal trauma. However, because of the complexity of the structures involved, minimal trauma can lead to significant disability later on. The process of erection requires correct functioning of the arterial, neurologic, and venous systems coupled with intact erectile bodies. The penis is composed of structures that are compliant and distensible to the limits of their compliance. These structures therefore tumesce in equal proportion to each other, allowing for straight erection. Relatively minimal trauma can upset this balance of elasticity, leading to disabling chordee. Likewise, relatively minimal injuries to the vascular erectile structures can lead to significantly disabling spongiofibrosis. The urethra is a conduit of paramount importance. Whereas the development of stricture is generally related to the nature of the trauma, the extent of stricture and of attendant complications is clearly a function of the immediate management. Overzealous debridement can greatly complicate subsequent reconstruction. A delicate balance between aggressive initial management and maximal preservation of viable structures must be achieved. 38 references.

  1. Trauma in pregnancy

    Directory of Open Access Journals (Sweden)

    A Rudra

    2007-01-01

    Full Text Available Trauma is the most common non-obstetrical cause of death in pregnant women. Pregnancy must always be suspected in any female trauma patient of childbearing age until proved otherwise. Unique changes in anatomy and physiology that takes place during pregnancy alter the pathophysiology and location of maternal injuries in pregnancy, which may be significantly different from the non-pregnant state. Trauma from road traffic accidents, falls and domestic violence are the most common causes of abdominal blunt trauma. As pregnancy progresses, the change of accidental injury increases. Head and neck injuries, respiratory failure, and hypovolemic shock constitute the most frequent causes of trauma related maternal death in pregnancy. Even the pregnant woman with minor injuries should be carefully observed. Initial management is directed at resuscitation and stabilization of the mother that takes precedence over that of the fetus, unless vital signs cannot be maintained and perimortem cesarean section decided upon. Fetal monitoring should be maintained after satisfactory resuscitation and stabilization of the mother. Preventive measures include proper seat belt use and identifying and counseling victims of suspected domestic violence.

  2. Air bubble migration is a random event post embryo transfer.

    Science.gov (United States)

    Confino, E; Zhang, J; Risquez, F

    2007-06-01

    Air bubble location following embryo transfer (ET) is the presumable placement spot of embryos. The purpose of this study was to document endometrial air bubble position and migration following embryo transfer. Multicenter prospective case study. Eighty-eight embryo transfers were performed under abdominal ultrasound guidance in two countries by two authors. A single or double air bubble was loaded with the embryos using a soft, coaxial, end opened catheters. The embryos were slowly injected 10-20 mm from the fundus. Air bubble position was recorded immediately, 30 minutes later and when the patient stood up. Bubble marker location analysis revealed a random distribution without visible gravity effect when the patients stood up. The bubble markers demonstrated splitting, moving in all directions and dispersion. Air bubbles move and split frequently post ET with the patient in the horizontal position, suggestive of active uterine contractions. Bubble migration analysis supports a rather random movement of the bubbles and possibly the embryos. Standing up changed somewhat bubble configuration and distribution in the uterine cavity. Gravity related bubble motion was uncommon, suggesting that horizontal rest post ET may not be necessary. This report challenges the common belief that a very accurate ultrasound guided embryo placement is mandatory. The very random bubble movement observed in this two-center study suggests that a large "window" of embryo placement maybe present.

  3. Optical measurement of bubbles: System design and application

    NARCIS (Netherlands)

    Leifer, I.; Leeuw, G.de; Cohen, L.H.

    2003-01-01

    Affordable high quality charge-coupled device (CCD) video cameras and image processing software are powerful tools for bubble measurements. Because of the wide variation between bubble populations, different bubble measurement systems (BMSs) are required depending upon the application. Two BMSs are

  4. Rhetoric, Risk, and Markets: The Dot-Com Bubble

    Science.gov (United States)

    Goodnight, G. Thomas; Green, Sandy Edward, Jr.

    2010-01-01

    Post-conventional economic theories are assembled to inquire into the contingent, mimetic, symbolic, and material spirals unfolding the dot-com bubble, 1992-2002. The new technologies bubble is reconstructed as a rhetorical movement across the practices of the hybrid market-industry risk culture of communications. The legacies of the bubble task…

  5. Modeling of flow in microchannel with bubbles layer on surface

    Directory of Open Access Journals (Sweden)

    Gluzdov Dmitriy

    2017-01-01

    Full Text Available Results of 2D numerical solution of liquid flow in microchannel with bubbles layers on surface are presented. Bubbles layers are modeled by setting of bubble size and Navier slip condition. Calculations have been done using OpenFoam PISO method. The results of modeling compared with analytical solution.

  6. Bubble size reduction in a fluidized bed by electric fields

    NARCIS (Netherlands)

    Kleijn van Willigen, F.; Van Turnhout, J.; Van Ommen, J.R.; Van den Bleek, C.

    2003-01-01

    The reduction of the size of bubbles can improve both selectivity and conversion in gas-solid fluidized beds. Results are reported of the reduction of bubble size by the application of electric fields to uncharged, polarizable particles in fluidized beds. It is shown how average bubble diameters can

  7. Nanoemulsions obtained via bubble bursting at a compound interface

    NARCIS (Netherlands)

    Feng, J.; Roche, M.; Vigolo, D.; Arnaudov, L.N.; Stoyanov, S.D.; Gurkov, T.D.; Tsutsumanova, G.G.; Stone, H.A.

    2014-01-01

    Bursting of bubbles at an air/liquid interface is a familiar occurrence relevant to foam stability, cell cultures in bioreactors and ocean–atmosphere mass transfer. In the latter case, bubble-bursting leads to the dispersal of sea-water aerosols in the surrounding air. Here we show that bubbles

  8. Bubbles as a means for the deaeration of water bodies

    NARCIS (Netherlands)

    Zhang, Yuhang; Zhou, Gedi; Prosperetti, Andrea

    2017-01-01

    Occasional dissolved-air supersaturation - such as may occur, for instance, downstream of dams - is harmful to fish because it causes gas bubble disease. A counterintuitive but effective means of reducing dissolved air content is the injection of bubbles in the supersaturated water. The bubbles

  9. Shape oscillation of bubbles in the acoustic field

    OpenAIRE

    Matsumoto, Keishi; Ueno, Ichiro

    2009-01-01

    The authors introduce dynamics of multiple air bubbles exposed to ultrasonic wave while ascending in water in the present fluid dynamics video. The authors pay attention to the shape oscillation and the transition from the volume to the shape oscillations of the bubble. Correlation between the bubble size and the mechanism of the excitation of the shape oscillation is introduced.

  10. Variability Of Plasma Bubble In The Equatorial Ionosphere At Midnight

    African Journals Online (AJOL)

    There are various types of ionospheric irregularities. Among these is the plasma bubble occurrence. They are most prominent at night time in the equatorial ionosphere. Many of the bubbles drift with approximately the velocity of the background plasma, but it is possible to infer that most bubbles have moved upward at some ...

  11. Maximal air bubble entrainment at liquid-drop impact

    NARCIS (Netherlands)

    Bouwhuis, W.; van der Veen, Roeland; Tran, Tuan; Keij, D.L.; Winkels, K.G.; Peters, I.R.; van der Meer, Roger M.; Sun, Chao; Snoeijer, Jacobus Hendrikus; Lohse, Detlef

    2012-01-01

    At impact of a liquid drop on a solid surface, an air bubble can be entrapped. Here, we show that two competing effects minimize the (relative) size of this entrained air bubble: for large drop impact velocity and large droplets, the inertia of the liquid flattens the entrained bubble, whereas for

  12. Drag an lift forces on bubbles in a rotating flow

    NARCIS (Netherlands)

    van Nierop, Ernst A.; Luther, S.; Bluemink, J.J.; Magnaudet, Jacques; Prosperetti, Andrea; Lohse, Detlef

    2007-01-01

    The motion of small air bubbles in a horizontal solid-body rotating flow is investigated experimentally. Bubbles with a typical radius of 1mm are released in a liquid-filled horizontally rotating cylinder. We measure the transient motion of the bubbles in solid-body rotation and their final

  13. Calibrating optical bubble size by the displaced-mass method.

    NARCIS (Netherlands)

    Leifer, I.; Leeuw, G. de; Kunz, G.; Cohen, L.H.

    2003-01-01

    Bubble sizing by optical means is very common, but requires calibration by non-optical means. This is particularly important since apparent bubble size increases with decreasing threshold intensity. A calibration experiment was conducted comparing the displaced water mass from captured bubbles with

  14. Fracture dislocation of the capitate following major trauma: A case report and literature review

    Directory of Open Access Journals (Sweden)

    Michael James Grant

    2017-12-01

    Conclusion: More patients are surviving major trauma events and have multiple complex limb injuries. We underscore the importance of having a high index of suspicion for complex injuries in high energy trauma and also the importance of appropriate and prompt management of such cases at specialized institutions. [Hand Microsurg 2017; 6(3.000: 146-149

  15. Program specialization

    CERN Document Server

    Marlet, Renaud

    2013-01-01

    This book presents the principles and techniques of program specialization - a general method to make programs faster (and possibly smaller) when some inputs can be known in advance. As an illustration, it describes the architecture of Tempo, an offline program specializer for C that can also specialize code at runtime, and provides figures for concrete applications in various domains. Technical details address issues related to program analysis precision, value reification, incomplete program specialization, strategies to exploit specialized program, incremental specialization, and data speci

  16. Multi-Dimensional Analysis of the Forced Bubble Dynamics Associated with Bubble Fusion Phenomena. Final Topical Report

    Energy Technology Data Exchange (ETDEWEB)

    Lahey, Jr., Richard T. [Rensselaer Polytechnic Inst., Troy, NY (United States). Center for Multiphase Research and Dept. of Mechanical, Aeronautical and Nuclear Engineering; Jansen, Kenneth E. [Rensselaer Polytechnic Inst., Troy, NY (United States). Center for Multiphase Research and Dept. of Mechanical, Aeronautical and Nuclear Engineering; Nagrath, Sunitha [Rensselaer Polytechnic Inst., Troy, NY (United States). Center for Multiphase Research and Dept. of Mechanical, Aeronautical and Nuclear Engineering

    2002-12-02

    A new adaptive grid, 3-D FEM hydrodynamic shock (ie, HYDRO )code called PHASTA-2C has been developed and used to investigate bubble implosion phenomena leading to ultra-high temperatures and pressures. In particular, it was shown that nearly spherical bubble compressions occur during bubble implosions and the predicted conditions associated with a recent ORNL Bubble Fusion experiment [Taleyarkhan et al, Science, March, 2002] are consistent with the occurrence of D/D fusion.

  17. Influence of the bubble-bubble interaction on destruction of encapsulated microbubbles under ultrasound.

    Science.gov (United States)

    Yasui, Kyuichi; Lee, Judy; Tuziuti, Toru; Towata, Atsuya; Kozuka, Teruyuki; Iida, Yasuo

    2009-09-01

    Influence of the bubble-bubble interaction on the pulsation of encapsulated microbubbles has been studied by numerical simulations under the condition of the experiment reported by Chang et al. [IEEE Trans. Ultrason Ferroelectr. Freq. Control 48, 161 (2001)]. It has been shown that the natural (resonance) frequency of a microbubble decreases considerably as the microbubble concentration increases to relatively high concentrations. At some concentration, the natural frequency may coincide with the driving frequency. Microbubble pulsation becomes milder as the microbubble concentration increases except at around the resonance condition due to the stronger bubble-bubble interaction. This may be one of the reasons why the threshold of acoustic pressure for destruction of an encapsulated microbubble increases as the microbubble concentration increases. A theoretical model for destruction has been proposed.

  18. Trauma-Focused CBT for Youth who Experience Ongoing Traumas

    OpenAIRE

    Cohen, Judith A.; Mannarino, Anthony P.; Murray, Laura A.

    2011-01-01

    Many youth experience ongoing trauma exposure, such as domestic or community violence. Clinicians often ask whether evidence-based treatments containing exposure components to reduce learned fear responses to historical trauma are appropriate for these youth. Essentially the question is, if youth are desensitized to their trauma experiences, will this in some way impair their responding to current or ongoing trauma? The paper addresses practical strategies for implementing one evidence-based ...

  19. Is Education Facing a "Tech Bubble"?

    Science.gov (United States)

    Davis, Michelle R.

    2013-01-01

    Educational technology companies and entrepreneurs may face the risk of a "tech bubble," similar to the massive boom-and-bust that rocked the technology market in the late 1990s, according to market analysts and a recently released paper. A relatively new focus on K-12 educational technology as an investment vehicle, a surge of investors looking…

  20. Ultrasound contrast agents : dynamics of coated bubbles

    NARCIS (Netherlands)

    Overvelde, M.L.J.

    2010-01-01

    Contrast-enhanced ultrasound imaging relies on the nonlinear scattering of microbubbles suspended in an ultrasound contrast agent. The bubble dynamics is described by a Rayleigh-Plesset-type equation, and the success of harmonic imaging using contrast agents has always been attributed to the

  1. Bubble growth on an impulsively powered microheater

    NARCIS (Netherlands)

    Yin, Z.; Prosperetti, Andrea; Kim, J.

    2004-01-01

    The dynamics of single vapor bubbles in FC-72 generated by a transient heat pulse applied to a square 260 × 260 μm2 microheater are investigated for different heat fluxes between 3 and 44 MW/m2. It is found that in all cases the growth consists of two steps, a first relatively violent one, followed

  2. Inert gas accumulation in sonoluminescing bubbles

    NARCIS (Netherlands)

    Lohse, Detlef; Hilgenfeldt, Sascha

    1997-01-01

    In this paper we elaborate on the idea [Lohse et al., Phys. Rev. Lett. 78, 1359-1362 (1997)] that (single) sonoluminescing air bubbles rectify argon. The reason for the rectification is that nitrogen and oxygen dissociate and their reaction products dissolve in water. We give further experimental

  3. Radiolytic and thermolytic bubble gas hydrogen composition

    Energy Technology Data Exchange (ETDEWEB)

    Woodham, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-12-11

    This report describes the development of a mathematical model for the estimation of the hydrogen composition of gas bubbles trapped in radioactive waste. The model described herein uses a material balance approach to accurately incorporate the rates of hydrogen generation by a number of physical phenomena and scale the aforementioned rates in a manner that allows calculation of the final hydrogen composition.

  4. Argonne Bubble Experiment Thermal Model Development II

    Energy Technology Data Exchange (ETDEWEB)

    Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-07-01

    This report describes the continuation of the work reported in “Argonne Bubble Experiment Thermal Model Development”. The experiment was performed at Argonne National Laboratory (ANL) in 2014. A rastered 35 MeV electron beam deposited power in a solution of uranyl sulfate, generating heat and radiolytic gas bubbles. Irradiations were performed at three beam power levels, 6, 12 and 15 kW. Solution temperatures were measured by thermocouples, and gas bubble behavior was observed. This report will describe the Computational Fluid Dynamics (CFD) model that was developed to calculate the temperatures and gas volume fractions in the solution vessel during the irradiations. The previous report described an initial analysis performed on a geometry that had not been updated to reflect the as-built solution vessel. Here, the as-built geometry is used. Monte-Carlo N-Particle (MCNP) calculations were performed on the updated geometry, and these results were used to define the power deposition profile for the CFD analyses, which were performed using Fluent, Ver. 16.2. CFD analyses were performed for the 12 and 15 kW irradiations, and further improvements to the model were incorporated, including the consideration of power deposition in nearby vessel components, gas mixture composition, and bubble size distribution. The temperature results of the CFD calculations are compared to experimental measurements.

  5. Non-Abelian bubbles in microstate geometries

    Science.gov (United States)

    Ramírez, Pedro F.

    2016-11-01

    We find the first smooth bubbling microstate geometries with non-Abelian fields. The solutions constitute an extension of the BPS three-charge smooth microstates. These consist in general families of regular supersymmetric solutions with non-trivial topology, i.e. bubbles, of {N}=d , d = 5 Super-Einstein-Yang-Mills theory, having the asymptotic charges of a black hole or black ring but with no horizon. The non-Abelian fields make their presence at the very heart of the microstate structure: the physical size of the bubbles is affected by the non-Abelian topological charge they carry, which combines with the Abelian flux threading the bubbles to hold them up. Interestingly the non-Abelian fields carry a set of adjustable continuous parameters that do not alter the asymptotics of the solutions but modify the local geometry. This feature can be used to obtain a classically infinite number of microstate solutions with the asymptotics of a single black hole or black ring.

  6. Big Bubbles in Boiling Liquids: Students' Views

    Science.gov (United States)

    Costu, Bayram

    2008-01-01

    The aim of this study was to elicit students' conceptions about big bubbles in boiling liquids (water, ethanol and aqueous CuSO[subscript 4] solution). The study is based on twenty-four students at different ages and grades. The clinical interviews technique was conducted to solicit students' conceptions and the interviews were analyzed to…

  7. Four-bubble clusters and Menelaus' theorem

    Science.gov (United States)

    Fischer, Fred

    2002-10-01

    We discuss a relatively easy way to construct a stable cluster of four soap bubbles using the radii of four selected spherical films out of a total of ten. To this end, we extend Menelaus' theorem, a geometrical relation between a triangle and a straight line in the plane, to three and higher dimensions.

  8. Soap-bubble Optimization of Gaits

    Science.gov (United States)

    Ramasamy, Suresh; Hatton, Ross

    We present a geometric gait optimizer that applies Lie bracket theory to identify optimal cost-of-transport (displacement divided by effort) gaits. This optimizer builds on our previous work, where we have shown that for drag-dominated systems, the efficiency of a gait corresponds to a ratio between ``metric-weighted perimeter length of the cycle and the area integral of the Lie bracket it encloses. In this work, we encode this geometric insight into a variational gait optimizer. For a system with two shape variables, the dynamics of this optimizer are similar to the dynamics of a soap bubble, with the Lie bracket providing internal pressure which causes the boundary of the bubble to expand, the metric-weighted path length providing surface tension constraining the growth of the soap bubble, and a pace-balancing term corresponding to the concentration gradient that evenly distributes soap across the surface of the bubble. In systems with three shape variables, the dynamics are more akin to a windsock, capturing maximum flux through a loop. The variational form of the optimizer allows us to extend it to higher dimensional shape spaces beyond these physical analogies.

  9. BUBBLE - an urban boundary layer meteorology project

    DEFF Research Database (Denmark)

    Rotach, M.W.; Vogt, R.; Bernhofer, C.

    2005-01-01

    The Basel urban Boundary Layer Experiment (BUBBLE) was a year-long experimental effort to investigate in detail the boundary layer structure in the City of Basel, Switzerland. At several sites over different surface types (urban, sub-urban and rural reference) towers up to at least twice the main...

  10. Non-Abelian bubbles in microstate geometries

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez, Pedro F. [Instituto de Física Teórica UAM/CSIC,C/ Nicolás Cabrera, 13-15, C.University Cantoblanco, E-28049 Madrid (Spain); Institut de Physique Théorique, Université Paris Saclay, CEA, CNRS,Orme des Merisiers bâtiment 774, F-91191 Gif-sur-Yvette (France)

    2016-11-24

    We find the first smooth bubbling microstate geometries with non-Abelian fields. The solutions constitute an extension of the BPS three-charge smooth microstates. These consist in general families of regular supersymmetric solutions with non-trivial topology, i.e. bubbles, of N=1, d=5 Super-Einstein-Yang-Mills theory, having the asymptotic charges of a black hole or black ring but with no horizon. The non-Abelian fields make their presence at the very heart of the microstate structure: the physical size of the bubbles is affected by the non-Abelian topological charge they carry, which combines with the Abelian flux threading the bubbles to hold them up. Interestingly the non-Abelian fields carry a set of adjustable continuous parameters that do not alter the asymptotics of the solutions but modify the local geometry. This feature can be used to obtain a classically infinite number of microstate solutions with the asymptotics of a single black hole or black ring.

  11. Heat transport in bubbling turbulent convection.

    Science.gov (United States)

    Lakkaraju, Rajaram; Stevens, Richard J A M; Oresta, Paolo; Verzicco, Roberto; Lohse, Detlef; Prosperetti, Andrea

    2013-06-04

    Boiling is an extremely effective way to promote heat transfer from a hot surface to a liquid due to numerous mechanisms, many of which are not understood in quantitative detail. An important component of the overall process is that the buoyancy of the bubble compounds with that of the liquid to give rise to a much-enhanced natural convection. In this article, we focus specifically on this enhancement and present a numerical study of the resulting two-phase Rayleigh-Bénard convection process in a cylindrical cell with a diameter equal to its height. We make no attempt to model other aspects of the boiling process such as bubble nucleation and detachment. The cell base and top are held at temperatures above and below the boiling point of the liquid, respectively. By keeping this difference constant, we study the effect of the liquid superheat in a Rayleigh number range that, in the absence of boiling, would be between 2 × 10(6) and 5 × 10(9). We find a considerable enhancement of the heat transfer and study its dependence on the number of bubbles, the degree of superheat of the hot cell bottom, and the Rayleigh number. The increased buoyancy provided by the bubbles leads to more energetic hot plumes detaching from the cell bottom, and the strength of the circulation in the cell is significantly increased. Our results are in general agreement with recent experiments on boiling Rayleigh-Bénard convection.

  12. Bridging Body and Mind: Considerations for Trauma-Informed Yoga.

    Science.gov (United States)

    Justice, Lauren; Brems, Christiane; Ehlers, Karrie

    2018-02-08

    Individuals who suffer from trauma-related symptoms are a unique population that could benefit from the mind-body practice of yoga-or have their symptoms reactivated by it, depending on the type of yoga. Trauma-informed yoga (TIY), that is, yoga adapted to the unique needs of individuals working to overcome trauma, may ameliorate symptoms by creating a safe, tailored practice for students to learn how to respond, rather than react, to symptoms and circumstances. Yoga not thus adapted, on the other hand, may increase reactivity and activate symptoms such as hyperarousal or dissociation. This article reports on expert input about adapting yoga for individuals with trauma, with special considerations for military populations. Eleven experts, recruited based on literature review and referrals, were interviewed in person or via telephone and asked seven questions about trauma-informed yoga. Verbatim transcripts were subjected to open-coding thematic analysis and a priori themes. Findings revealed that TIY needs to emphasize beneficial practices (e.g., diaphragmatic breath and restorative postures), consider contraindications (e.g., avoiding sequences that overly engage the sympathetic nervous system), adapt to limitations and challenges for teaching in unconventional settings (e.g., prisons, VA hospitals), and provide specialized training and preparation (e.g., specialized TIY certifications, self-care of instructors/therapists, adaptions for student needs). TIY for veterans must additionally consider gender- and culture-related barriers, differing relationships to pain and injury, and medication as a barrier to practice.

  13. Transfusion practices in trauma

    Directory of Open Access Journals (Sweden)

    V Trichur Ramakrishnan

    2014-01-01

    Full Text Available Resuscitation of a severely traumatised patient with the administration of crystalloids, or colloids along with blood products is a common transfusion practice in trauma patients. The determination of this review article is to update on current transfusion practices in trauma. A search of PubMed, Google Scholar, and bibliographies of published studies were conducted using a combination of key-words. Recent articles addressing the transfusion practises in trauma from 2000 to 2014 were identified and reviewed. Trauma induced consumption and dilution of clotting factors, acidosis and hypothermia in a severely injured patient commonly causes trauma-induced coagulopathy. Early infusion of blood products and early control of bleeding decreases trauma-induced coagulopathy. Hypothermia and dilutional coagulopathy are associated with infusion of large volumes of crystalloids. Hence, the predominant focus is on damage control resuscitation, which is a combination of permissive hypotension, haemorrhage control and haemostatic resuscitation. Massive transfusion protocols improve survival in severely injured patients. Early recognition that the patient will need massive blood transfusion will limit the use of crystalloids. Initially during resuscitation, fresh frozen plasma, packed red blood cells (PRBCs and platelets should be transfused in the ratio of 1:1:1 in severely injured patients. Fresh whole blood can be an alternative in patients who need a transfusion of 1:1:1 thawed plasma, PRBCs and platelets. Close monitoring of bleeding and point of care coagulation tests are employed, to allow goal-directed plasma, PRBCs and platelets transfusions, in order to decrease the risk of transfusion-related acute lung injury.

  14. Trauma-Focused CBT for Youth Who Experience Ongoing Traumas

    Science.gov (United States)

    Cohen, Judith A.; Mannarino, Anthony P.; Murray, Laura K.

    2011-01-01

    Many youth experience ongoing trauma exposure, such as domestic or community violence. Clinicians often ask whether evidence-based treatments containing exposure components to reduce learned fear responses to historical trauma are appropriate for these youth. Essentially the question is, if youth are desensitized to their trauma experiences, will…

  15. A method for indication and improving the position stability of the bubble in single-bubble cavitation experiments

    Science.gov (United States)

    Plocek, Jaroslav

    2017-10-01

    A newly developed method for indication of the bubble state in classical single-bubble cavitation experiments is introduced. The method is based on processing the signal from a sensor, positioned on the flask from outside. The technical means of the method are further explored to improve the position stability of the bubble.

  16. Modeling of mass transfer and chemical reactions in a bubble column reactor using a discrete bubble model

    NARCIS (Netherlands)

    Darmana, D.; Deen, N.G.; Kuipers, J.A.M.

    2004-01-01

    A 3D discrete bubble model is adopted to investigate complex behavior involving hydrodynamics, mass transfer and chemical reactions in a gas-liquid bubble column reactor. In this model a continuum description is adopted for the liquid phase and additionally each individual bubble is tracked in a

  17. Detailed modeling of hydrodynamics mass transfer and chemical reactions in a bubble column using a discrete bubble model

    NARCIS (Netherlands)

    Darmana, D.; Deen, N.G.; Kuipers, J.A.M.

    2005-01-01

    A 3D discrete bubble model is adopted to investigate complex behavior involving hydrodynamics, mass transfer and chemical reactions in a gas¿liquid bubble column reactor. In this model a continuum description is adopted for the liquid phase and additionally each individual bubble is tracked in a

  18. Trauma cardiaco cerrado

    OpenAIRE

    Alvarado, Camilo; Vargas, Fernando; Guzmán, Fernando; Zárate, Alejandro; Correa, José L.; Ramírez, Alejandro; Quintero, Diana M.; Ramírez, Erika M.

    2016-01-01

    El trauma cardiaco constituye una de las primeras causas de mortalidad en la población general. Requiere alto índice de sospecha en trauma cerrado severo, mecanismo de desaceleración y en presencia de signos indirectos como: equimosis, huella del volante o del cinturón en el tórax anterior. Las lesiones incluyen: conmoción cardiaca, ruptura cardiaca, lesión cardiaca indirecta como la trombosis coronaria aguda, lesión aórtica, lesión del pericardio y herniación cardiaca. Entre las manifestacio...

  19. Sonography of scrotal trauma

    Directory of Open Access Journals (Sweden)

    Meka Srinivasa Rao

    2012-01-01

    Full Text Available The purpose of this article is to depict the spectrum of scrotal injuries in blunt trauma. Scrotal injuries are not very common and are mostly due to blunt trauma from direct injury, sports injuries or motor vehicle accidents. To minimize complications and ensure testicular salvage, rapid and accurate diagnosis is necessary. High-resolution USG is the investigation of choice, as it is readily available, accurate and has been seen to improve outcomes. An understanding of and familiarity with the sonographic appearance of scrotal injuries on the part of the radiologist/sonographer is therefore of key importance.

  20. Operation Brain Trauma Therapy

    Science.gov (United States)

    2016-12-01

    Operation Brain Trauma Therapy. J Trauma 71(1 Suppl):S15-24, 2011. 2. Diaz-Arrastia R, Kochanek PM, Bergold P, Kenney K, Marx C, Grimes JB, Loh Y...severe traumatic brain injury. J. Neurotrauma 29, 1096–1104. 66. Diaz-Arrastia, R., Kochanek, P.M., Bergold, P., Kenney K, Marx CE, Grimes CJ, Loh LT...Proc. Nat. Acad. Sci. U.S.A. 96, 15268–15273. 4. Mendoza-Torreblanca, J.G., Vanoye- Carlo , A., Phillips-Farfan, B.V., Carmona-Aparicio, L., and

  1. Coagulopathy of Trauma.

    Science.gov (United States)

    Cohen, Mitchell J; Christie, S Ariane

    2017-01-01

    Coagulopathy is common after injury and develops independently from iatrogenic, hypothermic, and dilutional causes. Despite considerable research on the topic over the past decade, trauma-induced coagulopathy (TIC) continues to portend poor outcomes, including decreased survival. We review the current evidence regarding the diagnosis and mechanisms underlying trauma induced coagulopathy and summarize the debates regarding optimal management strategy including product resuscitation, potential pharmacologic adjuncts, and targeted approaches to hemostasis. Throughout, we will identify areas of continued investigation and controversy in the understanding and management of TIC. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. A derivation of the stable cavitation threshold accounting for bubble-bubble interactions.

    Science.gov (United States)

    Guédra, Matthieu; Cornu, Corentin; Inserra, Claude

    2017-09-01

    The subharmonic emission of sound coming from the nonlinear response of a bubble population is the most used indicator for stable cavitation. When driven at twice their resonance frequency, bubbles can exhibit subharmonic spherical oscillations if the acoustic pressure amplitude exceeds a threshold value. Although various theoretical derivations exist for the subharmonic emission by free or coated bubbles, they all rest on the single bubble model. In this paper, we propose an analytical expression of the subharmonic threshold for interacting bubbles in a homogeneous, monodisperse cloud. This theory predicts a shift of the subharmonic resonance frequency and a decrease of the corresponding pressure threshold due to the interactions. For a given sonication frequency, these results show that an optimal value of the interaction strength (i.e. the number density of bubbles) can be found for which the subharmonic threshold is minimum, which is consistent with recently published experiments conducted on ultrasound contrast agents. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Cavitation Bubble Nucleation by Energetic Particles

    Energy Technology Data Exchange (ETDEWEB)

    West, C.D.

    1998-12-01

    In the early sixties, experimental measurements using a bubble chamber confirmed quantitatively the thermal spike theory of bubble nucleation by energetic particles: the energy of the slow, heavy alpha decay recoils used in those experiments matched the calculated bubble nucleation energy to within a few percent. It was a triumph, but was soon to be followed by a puzzle. Within a couple of years, experiments on similar liquids, but well below their normal boiling points, placed under tensile stress showed that the calculated bubble nucleation energy was an order of magnitude less than the recoil energy. Why should the theory work so well in the one case and so badly in the other? How did the liquid, or the recoil particle, "know" the difference between the two experiments? Another mathematical model of the same physical process, introduced in 1967, showed qualitatively why different analyses would be needed for liquids with high and low vapor pressures under positive or negative pressures. But, the quantitative agreement between the calculated nucleation energy and the recoil energy was still poor--the former being smaller by a factor of two to three. In this report, the 1967 analysis is extended and refined: the qualitative understanding of the difference between positive and negative pressure nucleation, "boiling" and "cavitation" respectively, is retained, and agreement between the negative pressure calculated to be needed for nucleation and the energy calculated to be available is much improved. A plot of the calculated negative pressure needed to induce bubble formation against the measured value now has a slope of 1.0, although there is still considerable scatter in the individual points.

  4. Relationship between Liquidity and Price Bubble in Tehran's Asset Market

    Directory of Open Access Journals (Sweden)

    J. Khodaparast SHIRAZI

    2012-12-01

    Full Text Available In this paper, according to Austrian school, the existence of bubbles in asset market of Tehran from 1998 to 2009 is attributed to the unexpected fluctuations of liquidity. To find out the process of bubble, the state space form and Kalman filter are used and bubble is brought out as unobserved variable of price series. In order to determine the long run relationship between liquidity and price bubble the VAR method proposed by Johanson and Jelisus is used. The result confirms that variation of liquidity has a significant effect on the creating of bubble in long run.

  5. Path instabilities of air bubbles rising in clean water

    CERN Document Server

    Wu, M; Wu, Mingming; Gharib, Moteza

    1998-01-01

    Experiments are conducted to study the path and shape of single air bubbles (diameter range 0.10- 0.20cm) rising freely in clean water. The experimental results demonstrate that the bubble shape has a bistable state, i. e. the bubble chooses to be in spherical or ellipsoidal shape depending on its generation mechanism. The path of a spherical/ellipsoidal bubble is found to change from a straight path to a zigzag/spiral path via a supercritical/subcritical bifurcation when the Reynolds number of the bubble exceeds a threshold.

  6. Champagne experiences various rhythmical bubbling regimes in a flute.

    Science.gov (United States)

    Liger-Belair, Gérard; Tufaile, Alberto; Jeandet, Philippe; Sartorelli, José-Carlos

    2006-09-20

    Bubble trains are seen rising gracefully from a few points on the glass wall (called nucleation sites) whenever champagne is poured into a glass. As time passes during the gas-discharging process, the careful observation of some given bubble columns reveals that the interbubble distance may change suddenly, thus revealing different rhythmical bubbling regimes. Here, it is reported that the transitions between the different bubbling regimes of some nucleation sites during gas discharging is a process which may be ruled by a strong interaction between tiny gas pockets trapped inside the nucleation site and/or also by an interaction between the tiny bubbles just blown from the nucleation site.

  7. A note on the dynamics of two aligned bubbles perpendicular to and above a thin membrane

    Energy Technology Data Exchange (ETDEWEB)

    Aghdam, A Hajizadeh [Department of Mechanical Engineering, Arak University of Technology, Arak 3818141167 (Iran, Islamic Republic of); Khoo, B C, E-mail: Hajizadeh@arakut.ac.ir [Department of Mechanical Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260 (Singapore)

    2015-06-15

    The interaction of two perpendicular bubbles of a similar size (upper bubble and lower bubble) and the thin elastic membrane beneath them is studied experimentally. The dynamical behavior of the lower bubble (Bubble1), which is placed between the membrane and upper bubble (Bubble2), is rather complex. Observed phenomena such as the splitting of Bubble1 into the ‘mushroom shape’ and ‘masher shape’, the bubble-collapse induced jetting toward Bubble2 and even the coalescence effect are found and systematically categorized by the stated dimensionless parameters. (paper)

  8. Trauma Mortality Factors in the Elderly Population

    Directory of Open Access Journals (Sweden)

    Wen-Han Chang

    2008-03-01

    Full Text Available Trauma in the elderly population is frequent and is associated with significant mortality, owing not only to age-related factors, but also those complicated factors relating to lack of physical reserves, the injury severity, preexisting comorbidity, and insufficient ability for systemic compensation. Age-related mortality remains constant in the low to moderately severe injury categories compared with the severely injured groups (injury severity score, ISS, 25 or greater. The age-related insufficient physical reserves for cardiac output leave this group in the state of hypoperfusion, which is hard to identify. The circumstances around metabolic demands and lower maximum heart rate with a higher peripheral vascular resistance make the cardiovascular system reserve unable to respond, which means that a diagnosis of shock is more difficult to establish. Higher ISSs obtained at injury in the elderly population can predict higher mortality better than in younger population, but they have not been as effective in predicting mortality obtained at follow-up of elderly trauma patients compared with those at the time at injury. More aggressive care for the elderly trauma patient has been shown to decrease mortality. Because of the multiple mortality factors, a decision on treatment type following trauma in geriatric patients is unable to be made if the clinician is not alert to the pitfalls which can affect these individuals. Regardless of age or injury severity and with special considerations for those patients who arrive in a moribund condition, geriatric trauma patients should be treated with as much effort as their younger counterparts, that is, aggressively and within a certain time frame. [International Journal of Gerontology 2008; 2(1: 11–17

  9. Predawn plasma bubble cluster observed in Southeast Asia

    Science.gov (United States)

    Watthanasangmechai, Kornyanat; Yamamoto, Mamoru; Saito, Akinori; Tsunoda, Roland; Yokoyama, Tatsuhiro; Supnithi, Pornchai; Ishii, Mamoru; Yatini, Clara

    2016-06-01

    Predawn plasma bubble was detected as deep plasma depletion by GNU Radio Beacon Receiver (GRBR) network and in situ measurement onboard Defense Meteorological Satellite Program F15 (DMSPF15) satellite and was confirmed by sparse GPS network in Southeast Asia. In addition to the deep depletion, the GPS network revealed the coexisting submesoscale irregularities. A deep depletion is regarded as a primary bubble. Submesoscale irregularities are regarded as secondary bubbles. Primary bubble and secondary bubbles appeared together as a cluster with zonal wavelength of 50 km. An altitude of secondary bubbles happened to be lower than that of the primary bubble in the same cluster. The observed pattern of plasma bubble cluster is consistent with the simulation result of the recent high-resolution bubble (HIRB) model. This event is only a single event out of 76 satellite passes at nighttime during 3-25 March 2012 that significantly shows plasma depletion at plasma bubble wall. The inside structure of the primary bubble was clearly revealed from the in situ density data of DMSPF15 satellite and the ground-based GRBR total electron content.

  10. Daughter bubble cascades produced by folding of ruptured thin films.

    Science.gov (United States)

    Bird, James C; de Ruiter, Riëlle; Courbin, Laurent; Stone, Howard A

    2010-06-10

    Thin liquid films, such as soap bubbles, have been studied extensively for over a century because they are easily formed and mediate a wide range of transport processes in physics, chemistry and engineering. When a bubble on a liquid-gas or solid-gas interface (referred to herein as an interfacial bubble) ruptures, the general expectation is that the bubble vanishes. More precisely, the ruptured thin film is expected to retract rapidly until it becomes part of the interface, an event that typically occurs within milliseconds. The assumption that ruptured bubbles vanish is central to theories on foam evolution and relevant to health and climate because bubble rupture is a source for aerosol droplets. Here we show that for a large range of fluid parameters, interfacial bubbles can create numerous small bubbles when they rupture, rather than vanishing. We demonstrate, both experimentally and numerically, that the curved film of the ruptured bubble can fold and entrap air as it retracts. The resulting toroidal geometry of the trapped air is unstable, leading to the creation of a ring of smaller bubbles. The higher pressure associated with the higher curvature of the smaller bubbles increases the absorption of gas into the liquid, and increases the efficiency of rupture-induced aerosol dispersal.

  11. Numerical simulation of superheated vapor bubble rising in stagnant liquid

    Science.gov (United States)

    Samkhaniani, N.; Ansari, M. R.

    2017-09-01

    In present study, the rising of superheated vapor bubble in saturated liquid is simulated using volume of fluid method in OpenFOAM cfd package. The surface tension between vapor-liquid phases is considered using continuous surface force method. In order to reduce spurious current near interface, Lafaurie smoothing filter is applied to improve curvature calculation. Phase change is considered using Tanasawa mass transfer model. The variation of saturation temperature in vapor bubble with local pressure is considered with simplified Clausius-Clapeyron relation. The couple velocity-pressure equation is solved using PISO algorithm. The numerical model is validated with: (1) isothermal bubble rising and (2) one-dimensional horizontal film condensation. Then, the shape and life time history of single superheated vapor bubble are investigated. The present numerical study shows vapor bubble in saturated liquid undergoes boiling and condensation. It indicates bubble life time is nearly linear proportional with bubble size and superheat temperature.

  12. Modelling of Air Bubble Rising in Water and Polymeric Solution

    Science.gov (United States)

    Hassan, N. M. S.; Khan, M. M. K.; Rasul, M. G.; Subaschandar, N.

    2010-06-01

    This study investigates a Computational Fluid Dynamics (CFD) model for a single air bubble rising in water and xanthan gum solution. The bubble rise characteristics through the stagnant water and 0.05% xanthan gum solution in a vertical cylindrical column is modelled using the CFD code Fluent. Single air bubble rise dispersed into the continuous liquid phase has been considered and modelled for two different bubble sizes. Bubble velocity and vorticity magnitudes were captured through a surface-tracking technique i.e. Volume of Fluid (VOF) method by solving a single set of momentum equations and tracking the volume fraction of each fluid throughout the domain. The simulated results of the bubble flow contours at two different heights of the cylindrical column were validated by the experimental results and literature data. The model developed is capable of predicting the entire flow characteristics of different sizes of bubble inside the liquid column.

  13. Dynamics of micro-bubble sonication inside a phantom vessel

    KAUST Repository

    Qamar, Adnan

    2013-01-10

    A model for sonicated micro-bubble oscillations inside a phantom vessel is proposed. The model is not a variant of conventional Rayleigh-Plesset equation and is obtained from reduced Navier-Stokes equations. The model relates the micro-bubble oscillation dynamics with geometric and acoustic parameters in a consistent manner. It predicts micro-bubble oscillation dynamics as well as micro-bubble fragmentation when compared to the experimental data. For large micro-bubble radius to vessel diameter ratios, predictions are damped, suggesting breakdown of inherent modeling assumptions for these cases. Micro-bubble response with acoustic parameters is consistent with experiments and provides physical insight to the micro-bubble oscillation dynamics.

  14. The elasticity of soap bubbles containing wormlike micelles.

    Science.gov (United States)

    Sabadini, Edvaldo; Ungarato, Rafael F S; Miranda, Paulo B

    2014-01-28

    Slow-motion imaging of the rupture of soap bubbles generally shows the edges of liquid films retracting at a constant speed (known as the Taylor-Culick velocity). Here we investigate soap bubbles formed from simple solutions of a cationic surfactant (cetyltrimethylammonium bromide - CTAB) and sodium salicylate. The interaction of salicylate ions with CTAB leads to the formation of wormlike micelles (WLM), which yield a viscoelastic behavior to the liquid film of the bubble. We demonstrate that these elastic bubbles collapse at a velocity up to 30 times higher than the Taylor-Culick limit, which has never been surpassed. This is because during the bubble inflation, the entangled WLM chains stretch, storing elastic energy. This extra energy is then released during the rupture of the bubble, yielding an additional driving force for film retraction (besides surface tension). This new mechanism for the bursting of elastic bubbles may have important implications to the breakup of viscoelastic sprays in industrial applications.

  15. Numerical simulation of high Reynolds number bubble motion

    Energy Technology Data Exchange (ETDEWEB)

    McLaughlin, J.B. [Clarkson Univ., Potsdam, NY (United States)

    1995-12-31

    This paper presents the results of numerical simulations of bubble motion. All the results are for single bubbles in unbounded fluids. The liquid phase is quiescent except for the motion created by the bubble, which is axisymmetric. The main focus of the paper is on bubbles that are of order 1 mm in diameter in water. Of particular interest is the effect of surfactant molecules on bubble motion. Results for the {open_quotes}insoluble surfactant{close_quotes} model will be presented. These results extend research by other investigators to finite Reynolds numbers. The results indicate that, by assuming complete coverage of the bubble surface, one obtains good agreement with experimental observations of bubble motion in tap water. The effect of surfactant concentration on the separation angle is discussed.

  16. Dynamics of magnetic bubbles in acoustic and magnetic fields.

    Science.gov (United States)

    Zhao, Xue; Quinto-Su, Pedro A; Ohl, Claus-Dieter

    2009-01-16

    We report on shelled bubbles that can be manipulated with magnetic fields. The magnetic shell consists of self-assembled magnetic nanoparticles. The magnetic susceptibility of the bubbles is proportional to the surface area, chi_{b}=(9+/-3x10;{-6} m)r;{2} where r is the radius. Magnetic bubbles are compressible in moderate acoustic fields. A bubble with a radius of 121 mum oscillates in resonance in a sound field of 27 kHz with a peak-to-peak radial amplitude of 1.7 mum. The bubble oscillations induce a microstreaming flow with a toroidal vortex at the upper pole of the bubble. Further findings are the longevity of the magnetic bubbles and the ease of manipulation with standard magnets.

  17. Spatial and temporal film thickness measurement of a soap bubble based on large lateral shearing displacement interferometry.

    Science.gov (United States)

    Lv, Wei; Zhou, Huaichun; Lou, Chun; Zhu, Jinrong

    2012-12-20

    The film thickness of a hanging soap bubble has been studied along its gravitational orientation after its birth and before its bursting using large lateral shearing displacement interferometry, with a theoretical error of less than 0.325λ. The results show that the spatial distribution of the film thickness could be approximated with an exponential model in all captured frames, especially in the lower half of the soap bubble. Before its bursting, a special zone, where the water layer has drained out while the surfactant solution layer remains, will occur at the top of the soap bubble and gradually expand toward the bottom. Moreover, the simulated fringe patterns based on the computed values match well with the experimentally observed ones.

  18. Gênero e trauma Gender and trauma

    Directory of Open Access Journals (Sweden)

    Gláucio Ary Dillon Soares

    2005-04-01

    Full Text Available As conseqüências sociais e psicológicas da violência urbana sobre os parentes e amigos de pessoas vitimadas por mortes violentas (homicídio, suicídio ou acidentes são analisadas à luz das diferenças de gênero. A literatura especializada nesta área propõe que mulheres e homens vivenciam experiências traumáticas de forma peculiar. Porém, os traumas típicos são diferentes em cada gênero, deixando em aberto a questão sobre quanto das diferenças entre as respostas se devem a gênero e quanto se devem ao tipo de trauma. Testamos a hipótese de que as mulheres são mais suscetíveis à desordem de estresse pós-trauma (DEPT numa situação traumática comum, usando dados qualitativos e quantitativos. Comparamos os sintomas do trauma e as percepções sobre o significado da perda de seus entes queridos. A amostra, de 425 mulheres (62% e 265 homens (38%, foi retirada de uma lista de parentes de pessoas que sofreram morte violenta na cidade do Rio de Janeiro. Incluímos trinta relatos de parentes e amigos próximos das vítimas diretas. Os resultados revelaram que 54% das mulheres e 41% dos homens tiveram o cotidiano alterado depois da morte de um parente/amigo. Há diferenças estatisticamente significativas nos problemas de saúde e na diversão. Essa área foi a mais afetada, atingindo metade dos entrevistados. Uma variável intimamente correlacionada com os sintomas da DEPT é o contato com o corpo: controlando a extensão do contato (fez o reconhecimento do corpo; viu, mas não reconheceu e nem viu nem reconheceu. Em cada uma dessas categorias, as mulheres foram mais afetadas do que os homens. O artigo conclui que as mulheres sentem mais as perdas do que os homens, mas que parte das diferenças não são internas aos gêneros, mas externas a eles, dependendo das interações e dos contatos pessoais.The social and psychological consequences endured by friends and relatives of people victimized by violent death (homicide, suicide or

  19. Scintigraphy In skeletal trauma

    African Journals Online (AJOL)

    1989-08-05

    Aug 5, 1989 ... Five case reports demonstrate the value of bone scintigraphy in trauma. The bone scans clearly demonstrated fractures of the hip and pelvis that were not radiologically evident or the presence of which was doubtful, and also identified a number of unsuspected fractures in a patient with multiple injuries.

  20. Trauma and Symbolic Violence

    DEFF Research Database (Denmark)

    Pedersen, Bodil Maria

    2011-01-01

    Our understanding of 'reactions to trauma' is dominated by concepts like Post-Traumatic Stress Disorder. The use of such concepts has been criticised but simultaneously integrated in folk-psychology. Connecting emotional and cognitive processes as well as acts - such as in gendered practices - to...

  1. Trauma and Symbolic Violence

    DEFF Research Database (Denmark)

    Pedersen, Bodil Maria

    2011-01-01

    Our understanding of 'reactions to trauma' is dominated by concepts like Post-Traumatic Stress Disorder. The use of such concepts has been criticised but simultaneously integrated in folk-psychology. Connecting emotional and cognitive processes as well as acts - such as in gendered practices...

  2. Trauma - the malignant epidemic

    African Journals Online (AJOL)

    life are lost annually from trauma than malignant disease, heart disease, and AIDS combined, and by the ... diffused and rapidly spreading condition affecting many people in anyone region at the same time and tending ... upon inadequate and overcrowded methods of transportation. TABLE I. INTERPERSONAL VIOLENCE ...

  3. Early Childhood Trauma

    Science.gov (United States)

    National Child Traumatic Stress Network, 2010

    2010-01-01

    Early childhood trauma generally refers to the traumatic experiences that occur to children aged 0-6. Because infants' and young children's reactions may be different from older children's, and because they may not be able to verbalize their reactions to threatening or dangerous events, many people assume that young age protects children from the…

  4. Tumour, Torsion or Trauma?

    African Journals Online (AJOL)

    finally revealed testicular torsion. Remarkably, the testis was viable and the finding of a hematoma of the epididymis suggested a history of trauma which was not forthcoming from the patient. The acute scrotum demands expeditious attention and the clinician must aim to reach a definitive diagnosis in the shortest time ...

  5. Operation Brain Trauma Therapy

    Science.gov (United States)

    2014-10-01

    OBTT.85 However, blunting of hyperglycemia that is seen in CNS insults could play some role in the observed benefit. 18 Beam Balance Days Post...62. Abrahamson EE, Ikonomovic MD, Dixon CE, DeKosky ST. Simvastatin therapy prevents brain trauma- induced increases in β-amyloid peptide levels

  6. Traumatismos oculares Ocular traumas

    Directory of Open Access Journals (Sweden)

    Gelen Welch Ruiz

    2007-12-01

    Full Text Available Se realizó un estudio descriptivo de tipo retrospectivo longitudinal cuyo universo estuvo constituido por 72 ojos de 72 pacientes con traumatismos oculares mecánicos que fueron hospitalizados en el Hospital Militar Central “Dr. Carlos J. Finlay” desde enero de 1999 hasta enero de 2005. Para el análisis estadístico de la información se utilizó el programa automatizado SPSS versión 11.5 en el cual también se conformó la base de datos y se realizaron los cálculos de acuerdo con el tipo de variable analizada. Se utilizaron medidas de resumen, tendencia central y asociación estadística con un nivel de significación de p A retrospective longitudinal and descriptive study was carried out in 72 eyes from 72 patients with mechanical occular traumas, who had been hospitalized in “Dr. Carlos J. Finlay” Military Hospital from December 1999 to January 2005. For the statistical data analysis, an automated program (SPSS 11.5 version was used to create the database and estimations were made according to the variable types. Summary measures, central tendency measures and statistical association with significance level equal to p < 0.05 were employed. Males prevailed (95.8%, the average age was 30.26 years with a minimum rate of 17 years and maximum rate of 82 years. The most frequent mechanisms of trauma were aggressions (23. 6% and injures from secondary projectiles (13.9%. The anterior segment traumas were more frequent (61, 1% than posterior segment traumas (6.94%. Both segments of the eyeball were affected in 39, 1% of eyes which evinced the worst visual acuity. The most common associated injures were hyphema (54, 2% and vitreous hemorrhage (16.6%. Closed trauma (contusions were more common and most of the eyes had better final visual acuity (45, 2% with vision range of 0.6-1.0 and 26.2% with vision range of 0.59-0.1. On the other hand, eyes affected by open trauma (simple wound, contusion-wound, wound with intraocular foreign body and

  7. Lithotripter shock wave interaction with a bubble near various biomaterials

    Science.gov (United States)

    Ohl, S. W.; Klaseboer, E.; Szeri, A. J.; Khoo, B. C.

    2016-10-01

    Following previous work on the dynamics of an oscillating bubble near a bio-material (Ohl et al 2009 Phys. Med. Biol. 54 6313-36) and the interaction of a bubble with a shockwave (Klaseboer et al 2007 J. Fluid Mech. 593 33-56), the present work concerns the interaction of a gas bubble with a traveling shock wave (such as from a lithotripter) in the vicinity of bio-materials such as fat, skin, muscle, cornea, cartilage, and bone. The bubble is situated in water (to represent a water-like biofluid). The bubble collapses are not spherically symmetric, but tend to feature a high speed jet. A few simulations are performed and compared with available experimental observations from Sankin and Zhong (2006 Phys. Rev. E 74 046304). The collapses of cavitation bubbles (created by laser in the experiment) near an elastic membrane when hit by a lithotripter shock wave are correctly captured by the simulation. This is followed by a more systematic study of the effects involved concerning shockwave bubble biomaterial interactions. If a subsequent rarefaction wave hits the collapsed bubble, it will re-expand to a very large size straining the bio-materials nearby before collapsing once again. It is noted that, for hard bio-material like bone, reflection of the shock wave at the bone—water interface can affect the bubble dynamics. Also the initial size of the bubble has a significant effect. Large bubbles (˜1 mm) will split into smaller bubbles, while small bubbles collapse with a high speed jet in the travel direction of the shock wave. The numerical model offers a computationally efficient way of understanding the complex phenomena involving the interplay of a bubble, a shock wave, and a nearby bio-material.

  8. Tracking of Bubble Trajectories in Vertical Pipes in Bubbly Flow Regime by Coupling Lagrangian, Eulerian and 3D Random Walks Models: Validation with Experimental Data

    Directory of Open Access Journals (Sweden)

    José L. Muñoz-Cobo

    2012-09-01

    Full Text Available A set of air-water experiments has been performed under isothermal upward concurrent flow conditions, in a vertical column. The interfacial velocity, the bubble interfacial area and the void fraction distributions have been measured. Numerical simulation of these experiments were performed by coupling a Lagrangian code which tracks the 3D motion of the individual bubbles, with an Eulerian one. In the Eulerian solver the velocity and turbulence fields of the liquid phase were computed by solving the time dependent conservation equations in its Reynolds Averaged Transport Equation form (RANS. The turbulent kinetic energy k, and the dissipation rate transport equations were simultaneously solved by using the k, epsilon model in a (r,z grid by the finite volume method and the SIMPLER algorithm. Both Lagrangian and Eulerian calculations were performed in parallel and an iterative self-consistent method was developed. The turbulence induced by the bubbles is an important issue considered in this paper, in order to obtain good predictions of the void fraction distribution and the interfacial velocity at different gas and liquid flow conditions. The Eulerian Code was upgraded from an axisymmetric 2D code to a 3D code in order to improve the turbulence solution. The results of the 3D CFD code have been tested and show a good agreement with the experimental results. In this paper special attention is given to the coupling between the different models.

  9. Bubble Proliferation in Shock Wave Lithotripsy Occurs during Inertial Collapse

    Science.gov (United States)

    Pishchalnikov, Yuri A.; McAteer, James A.; Pishchalnikova, Irina V.; Williams, James C.; Bailey, Michael R.; Sapozhnikov, Oleg A.

    2008-06-01

    In shock wave lithotripsy (SWL), firing shock pulses at slow pulse repetition frequency (0.5 Hz) is more effective at breaking kidney stones than firing shock waves (SWs) at fast rate (2 Hz). Since at fast rate the number of cavitation bubbles increases, it appears that bubble proliferation reduces the efficiency of SWL. The goal of this work was to determine the basis for bubble proliferation when SWs are delivered at fast rate. Bubbles were studied using a high-speed camera (Imacon 200). Experiments were conducted in a test tank filled with nondegassed tap water at room temperature. Acoustic pulses were generated with an electromagnetic lithotripter (DoLi-50). In the focus of the lithotripter the pulses consisted of a ˜60 MPa positive-pressure spike followed by up to -8 MPa negative-pressure tail, all with a total duration of about 7 μs. Nonlinear propagation steepened the shock front of the pulses to become sufficiently thin (˜0.03 μm) to impose differential pressure across even microscopic bubbles. High-speed camera movies showed that the SWs forced preexisting microbubbles to collapse, jet, and break up into daughter bubbles, which then grew rapidly under the negative-pressure phase of the pulse, but later coalesced to re-form a single bubble. Subsequent bubble growth was followed by inertial collapse and, usually, rebound. Most, if not all, cavitation bubbles emitted micro-jets during their first inertial collapse and re-growth. After jetting, these rebounding bubbles could regain a spherical shape before undergoing a second inertial collapse. However, either upon this second inertial collapse, or sometimes upon the first inertial collapse, the rebounding bubble emerged from the collapse as a cloud of smaller bubbles rather than a single bubble. These daughter bubbles could continue to rebound and collapse for a few cycles, but did not coalesce. These observations show that the positive-pressure phase of SWs fragments preexisting bubbles but this initial

  10. Maternofetal Trauma in Craniosynostosis.

    Science.gov (United States)

    Swanson, Jordan; Oppenheimer, Adam; Al-Mufarrej, Faisal; Pet, Mitchell; Arakawa, Chris; Cunningham, Michael; Gruss, Joseph; Hopper, Richard; Birgfeld, Craig

    2015-08-01

    Premature cranial suture fusion may prevent neonatal skull malleability during birth, increasing the risk of unplanned cesarean delivery and neonatal birth trauma caused by cephalopelvic disproportion. We sought to determine the incidence of perinatal maternofetal complications in cases of craniosynostosis. Records of children presenting with nonsyndromic craniosynostosis to a tertiary pediatric hospital from 1996 to 2012 were reviewed retrospectively with focus on birth history and birth-related complications. Six hundred eighteen births were reviewed. Rates of cesarean delivery among mothers of children with craniosynostosis [n = 201 (32.5 percent)] exceeded the overall regional rate of 24.5 percent (OR, 1.50; p < 0.0001). Unplanned cesarean delivery occurred in 19.7 percent of births, and were most associated with nulliparous mothers, breech fetal presentations, and lambdoid or multisuture synostosis patterns. Eleven neonates (1.8 percent) exhibited cranial birth trauma, including cephalohematoma and subgaleal hematoma. Neonates with sagittal or multisuture synostosis patterns were more likely to suffer birth trauma and had a higher mean head circumference than those who did not (81st versus 66th percentile, p < 0.05). In the setting of craniosynostosis, birth trauma is increased-for mothers in the form of increased cesarean delivery risk, and for fetuses in the form of subgaleal and subperiosteal perinatal bleeding. Difficult maternal labor may be mediated especially by multisuture or lambdoid synostosis, whereas fetal birth trauma may be mediated to a greater extent by large head size. Prenatal diagnosis of craniosynostosis could influence decision-making in the management of labor. Risk, IV.

  11. Penetrating ureteral trauma

    Directory of Open Access Journals (Sweden)

    Gustavo P. Fraga

    2007-04-01

    Full Text Available OBJECTIVE: The purpose of this series is to report our experience in managing ureteral trauma, focusing on the importance of early diagnosis, correct treatment, and the impact of associated injuries on the management and morbid-mortality. MATERIALS AND METHODS: From January 1994 to December 2002, 1487 laparotomies for abdominal trauma were performed and 20 patients with ureteral lesions were identified, all of them secondary to penetrating injury. Medical charts were analyzed as well as information about trauma mechanisms, diagnostic routine, treatment and outcome. RESULTS: All patients were men. Mean age was 27 years. The mechanisms of injury were gunshot wounds in 18 cases (90% and stab wounds in two (10%. All penetrating abdominal injuries had primary indication of laparotomy, and neither excretory urography nor computed tomography were used in any case before surgery. The diagnosis of ureteric injury was made intra-operatively in 17 cases (85%. Two ureteral injuries (10% were initially missed. All patients had associated injuries. The treatment was dictated by the location, extension and time necessary to identify the injury. The overall incidence of complications was 55%. The presence of shock on admission, delayed diagnosis, Abdominal Trauma Index > 25, Injury Severity Score > 25 and colon injuries were associated to a high complication rate, however, there was no statistically significant difference. There were no mortalities in this group. CONCLUSIONS: A high index of suspicion is required for diagnosis of ureteral injuries. A thorough exploration of all retroperitoneal hematoma after penetrating trauma should be an accurate method of diagnosis; even though it failed in 10% of our cases.

  12. Imaging in spinal trauma

    Energy Technology Data Exchange (ETDEWEB)

    Goethem, J.W.M. van [Universitair Ziekenhuis Antwerpen, University of Antwerp, Belgium, Department of Radiology, Edegem (Belgium); Algemeen Ziekenhuis Maria Middelares, Department of Radiology, Sint-Niklaas (Belgium); Maes, Menno; Oezsarlak, Oezkan; Hauwe, Luc van den; Parizel, Paul M. [Universitair Ziekenhuis Antwerpen, University of Antwerp, Belgium, Department of Radiology, Edegem (Belgium)

    2005-03-01

    Because it may cause paralysis, injury to the spine is one of the most feared traumas, and spinal cord injury is a major cause of disability. In the USA approximately 10,000 traumatic cervical spine fractures and 4000 traumatic thoracolumbar fractures are diagnosed each year. Although the number of individuals sustaining paralysis is far less than those with moderate or severe brain injury, the socioeconomic costs are significant. Since most of the spinal trauma patients survive their injuries, almost one out of 1000 inhabitants in the USA are currently being cared for partial or complete paralysis. Little controversy exists regarding the need for accurate and emergent imaging assessment of the traumatized spine in order to evaluate spinal stability and integrity of neural elements. Because clinicians fear missing occult spine injuries, they obtain radiographs for nearly all patients who present with blunt trauma. We are influenced on one side by fear of litigation and the possible devastating medical, psychologic and financial consequences of cervical spine injury, and on the other side by pressure to reduce health care costs. A set of clinical and/or anamnestic criteria, however, can be very useful in identifying patients who have an extremely low probability of injury and who consequently have no need for imaging studies. Multidetector (or multislice) computed tomography (MDCT) is the preferred primary imaging modality in blunt spinal trauma patients who do need imaging. Not only is CT more accurate in diagnosing spinal injury, it also reduces imaging time and patient manipulation. Evidence-based research has established that MDCT improves patient outcome and saves money in comparison to plain film. This review discusses the use, advantages and disadvantages of the different imaging techniques used in spinal trauma patients and the criteria used in selecting patients who do not need imaging. Finally an overview of different types of spinal injuries is given

  13. MANAGEMENT OF LIVER TRAUMA

    Directory of Open Access Journals (Sweden)

    Dova Subba

    2016-03-01

    Full Text Available AIM To estimate the incidence of Liver Trauma injuries and grade their severity of injury. To assess the factors responsible for morbidity and mortality after Liver Trauma. To study the postoperative complications and the management of Liver Trauma. MATERIALS AND METHODS The present prospective study was conducted on 100 patients who were admitted to Department of General Surgery for treatment who were managed operatively or non-operatively for abdominal trauma and having liver injury forms the material of the study. This study was conducted over a span of 24 months from June 2013 to November 2015. RESULTS Maximum number of patients are in the age group of 21-30 years (46%. 85% patients (85/100 are males and 15% of patients (15/100 are females. Lapse time of injury and admission varied from 25 minutes to 66 hours and 30 minutes. 75 % of the patients (75/100 presented within 24 hours after injury. Death rate of patients who reached hospital after 24 hours of injury was higher than the patients who reached hospital within 24 hours of injury. 28% of patients (28/100 had associated bony injuries, out of which 5% of patients (5/100 expired due to primary haemorrhage of fractured femur. More than one segment was injured in many patients. Segment V is involved commonly making 55% (55/100 of patients. Next common segment involved is segment VII, making 39% (39/100. CONCLUSION Mechanism of injury is the important factor which is responsible for morbidity in liver injury. Nonoperative management proved to be safe and effective and often has been used to treat patients with liver trauma.

  14. Trauma-Induced Coagulopathy.

    Science.gov (United States)

    Simmons, Jeffrey W; Pittet, Jean-Francois; Pierce, Bert

    2014-09-01

    Trauma is the leading cause of death among people under the age of 44. Hemorrhage is a major contributor to deaths related to trauma in the first 48 h. Accordingly, the management of these patients is a time-sensitive and critical affair that anesthesiologists responsible for surgical resuscitation will face. Coagulopathy associated with trauma exists in one-third of all severely injured patients upon presentation to the hospital. Trauma patients presenting with coagulopathy have significantly higher mortality. This trauma-induced coagulopathy (TIC) must be managed adroitly in the resuscitation of these patients. Recent advancements in our understanding of TIC have led to new protocols and therapy guidelines. Anesthesiologists must be aware of these to effectively manage this form of shock. TIC driven by a combination of endogenous biological processes, as well as iatrogenic causes, can ultimately lead to the lethal triad of hypothermia, acidemia, and coagulopathy. Providers should understand how to promptly diagnose TIC and be aware of the early indicators of massive transfusion. The use of common laboratory studies and patient vital signs serve as our current guide, but the importance of each is still under debate. Thromboelastography is a tool used often in the diagnosis of TIC and can be used to guide blood product transfusion. Certain pharmaceutical strategies and non-transfusion strategies also exist, which aid in the management of hemorrhagic shock. Damage control surgery, rewarming, tranexamic acid, and 1:1:1 transfusion protocols are promising methods used to treat the critically wounded. Though protocols have been developed, controversies still exist on the optimal resuscitation strategy.

  15. Paediatric trauma care

    Directory of Open Access Journals (Sweden)

    Sebastian van As A

    2010-01-01

    Full Text Available Background: Childhood trauma has become a major cause of mortality and morbidity, disability and socio-economic burden and it is expected by the World Health Organization (WHO that by 2020 it will be the number 1 disease globally. The WHO and UNICEF have published their third World Report on Child Injury Prevention in December 2008. Materials and Methods: A systematic review was performed on the history and magnitude of paediatric trauma worldwide. Additionally exciting developments and new trends were assessed and summarized. Results: Paediatric trauma is a growing field of clinical expertise. New developments include total body digital imaging of children presenting with polytrauma; targeted management of head injuries; conservative management of abdominal injuries in children and diagnostic laparoscopy, including the laparoscopic management of complications following the conservative management of solid organ injuries. Conclusion: Paediatric trauma has long been neglected by the medical profession. In order to deal with it appropriately, it makes sense to adopt the public health approach, requiring that we view child injuries similarly to any other disease or health problem. The greatest gain in our clinical practice with dealing with child injuries will result from a strong focus on primary (preventing the injury, secondary (dealing with the injury in the most efficient manner as well as tertiary prevention (making sure that children treated for trauma will be appropriately reintegrated within our society. By actively promoting child safety we will not only achieve a most welcome reduction in medical cost and disability, but also the ever-so-much desired decline of avoidable childhood misery and suffering.

  16. Measurements of fast neutrons by bubble detectors

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, F.; Martinez, H. [Laboratorio de Espectroscopia, Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62251, Cuernavaca Morelos (Mexico); Leal, B. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, 04510, Ciudad Universitaria, Mexico D. F. (Mexico); Rangel, J. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, 04510, Ciudad Universitaria, Mexico D. F (Mexico); Reyes, P. G. [Facultad de Ciencias, Universidad Autonoma del Estado de Mexico, Instituto Literario 100, Col. Centro, 50000, Toluca Estado de Mexico (Mexico)

    2013-07-03

    Neutron bubble detectors have been studied using Am-Be and D-D neuron sources, which give limited energy information. The Bubble Detector Spectrometer (BDS) have six different energy thresholds ranging from 10 KeV to 10 Mev. The number of bubbles obtained in each measurement is related to the dose (standardized response R) equivalent neutrons through sensitivity (b / {mu}Sv) and also with the neutron flux (neutrons per unit area) through a relationship that provided by the manufacturer. Bubble detectors were used with six different answers (0.11 b/ {mu}Sv, 0093 b/{mu}Sv, 0.14 b/{mu}Sv, 0.17 b/{mu}Sv, 0051 b/{mu}Sv). To test the response of the detectors (BDS) radiate a set of six of them with different energy threshold, with a source of Am-Be, placing them at a distance of one meter from it for a few minutes. Also, exposed to dense plasma focus Fuego Nuevo II (FN-II FPD) of ICN-UNAM, apparatus which produces fusion plasma, generating neutrons by nuclear reactions of neutrons whose energy emitting is 2.45 MeV. In this case the detectors were placed at a distance of 50 cm from the pinch at 90 Degree-Sign this was done for a certain number of shots. In both cases, the standard response is reported (Dose in {mu}Sv) for each of the six detectors representing an energy range, this response is given by the expression R{sub i}= B{sub i} / S{sub i} where B{sub i} is the number of bubbles formed in each and the detector sensitivity (S{sub i}) is given for each detector in (b / {mu}Sv). Also, reported for both cases, the detected neutron flux (n cm{sup -2}), by a given ratio and the response involves both standardized R, as the average cross section sigma. The results obtained have been compared with the spectrum of Am-Be source. From these measurements it can be concluded that with a combination of bubble detectors, with different responses is possible to measure the equivalent dose in a range of 10 to 100 {mu}Sv fields mixed neutron and gamma, and pulsed generated fusion

  17. Optical monitoring of bubble size and shape in a pulsating bubble surfactometer.

    Science.gov (United States)

    Seurynck, Shannon L; Brown, Nathan J; Wu, Cindy W; Germino, Kevin W; Kohlmeir, Ellen K; Ingenito, Edward P; Glucksberg, Matthew R; Barron, Annelise E; Johnson, Mark

    2005-08-01

    The pulsating bubble surfactometer (PBS) is often used for in vitro characterization of exogenous lung surfactant replacements and lung surfactant components. However, the commercially available PBS is not able to dynamically track bubble size and shape. The PBS therefore does not account for bubble growth or elliptical bubble shape that frequently occur during device use. More importantly, the oscillatory volume changes of the pulsating bubble are different than those assumed by the software of the commercial unit. This leads to errors in both surface area and surface tension measurements. We have modified a commercial PBS through the addition of an image-acquisition system, allowing real-time determination of bubble size and shape and hence the accurate tracking of surface area and surface tension. Compression-expansion loops obtained with the commercially available PBS software were compared with those provided by the image-analysis system for dipalmitoylphosphatidylcholine, Infasurf, and Tanaka lipids (dipalmitoylphosphatidylcholine-palmitoyloleoylphosphatidyl-glycerol-palmitic acid, 68:22:9) at concentrations of 0.1 and 1.0 mg/ml and at frequencies of 1 and 20 cycles/min. Whereas minimum surface tension as determined by the image-analysis system is similar to that measured by the commercially available software, the maximum surface tension and the shapes of the interfacial area-surface tension loops are quite different. Differences are attributable to bubble drift, nonsinusoidal volume changes, and variable volume excursions seen with the modified system but neglected by the original system. Image analysis reveals that the extent of loop hysteresis is greatly overestimated by the commercial device and that an apparent, rapid increase in surface tension upon film expansion seen in PBS loops is not observed with the image-analysis system. The modified PBS system reveals new dynamic characteristics of lung surfactant preparations that have not previously been

  18. General surgeon management of complex hepatopancreatobiliary trauma at a level I trauma center.

    Science.gov (United States)

    Kilen, Peter; Greenbaum, Alissa; Miskimins, Richard; Rojo, Manuel; Preda, Razvan; Howdieshell, Thomas; Lu, Stephen; West, Sonlee

    2017-09-01

    The impact of general surgeons (GS) taking trauma call on patient outcomes has been debated. Complex hepatopancreatobiliary (HPB) injuries present a particular challenge and often require specialized care. We predicted no difference in the initial management or outcomes of complex HPB trauma between GS and trauma/critical care (TCC) specialists. A retrospective review of patients who underwent operative intervention for complex HPB trauma from 2008 to 2015 at an ACS-verified level I trauma center was performed. Chart review was used to obtain variables pertaining to demographics, clinical presentation, operative management, and outcomes. Patients were grouped according to whether their index operation was performed by a GS or TCC provider and compared. 180 patients met inclusion criteria. The GS (n = 43) and TCC (n = 137) cohorts had comparable patient demographics and clinical presentations. Most injuries were hepatic (73.3% GS versus 72.6% TCC) and TCC treated more pancreas injuries (15.3% versus GS 13.3%; P = 0.914). No significant differences were found in HPB-directed interventions at the initial operation (41.9% GS versus 56.2% TCC; P = 0.100), damage control laparotomy with temporary abdominal closure (69.8% versus 69.3%; P = 0.861), LOS, septic complications or 30-day mortality (13.9% versus 10.2%; P = 0.497). TCC were more likely to place an intraabdominal drain than GS (52.6% versus 34.9%; P = 0.043). We found no significant differences between GS and TCC specialists in initial operative management or clinical outcomes of complex HPB trauma. The frequent and proper use of damage control laparotomy likely contribute to these findings. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. An investigation of small-molecule surfactants to potentially replace pluronic F-68 for reducing bubble-associated cell damage.

    Science.gov (United States)

    Hu, Weiwei; Rathman, James J; Chalmers, Jeffrey J

    2008-09-01

    It is well known that bubble rupture has a detrimental effect on mammalian cells. As a result, Pluronic F-68 (PF-68), a nonionic surfactant, is commonly used to reduce bubble-associated cell damage in sparged bioreactors. While PF-68 is currently effective, there is a concern with respect to its decrease in effectiveness as cell concentrations increase (Ma et al., 2004, Biotechnol Prog 20:1183-1191). In addition, having more than one effective surfactant for cell culture is also highly desirable. Given the empirical nature in which PF-68 was initially discovered as a cell culture additive, a structure-performance study of small molecule surfactants, a distinct group which have been previously investigated for other purposes, was performed in an attempt to find a replacement for PF-68. In this study, a generic platform was established to initially screen both the type and concentration of these surfactants for cytotoxicity. Promising candidates where then evaluated for their ability to rapidly lower the surface tension (dynamic surface tension) of culture media and their ability to prevent cell-bubble attachment in a specially developed bubble creation and collection system. Several promising small- molecule surfactants, and their effective concentration, were identified, which can reduce cell-bubble attachment efficiently without being harmful to cells.

  20. CS EMISSION NEAR MIR-BUBBLES

    Energy Technology Data Exchange (ETDEWEB)

    Watson, C. [Manchester University, Department of Physics, 604 E. College Ave., North Manchester, IN 46962 (United States); Devine, Kathryn [College of Idaho, Department of Physics, 2112 Cleveland Blvd, Caldwell, ID 83605 (United States); Quintanar, N. [Texas A and M University, Department of Nuclear Engineering, 401 Joe Routt Blvd, College Station, TX 77843 (United States); Candelaria, T., E-mail: cwatson@manchester.edu, E-mail: KDevine@collegeofidaho.edu, E-mail: nrquintanar@tamu.edu, E-mail: tcandela@nmt.edu [New Mexico Institute of Mining and Technology, Department of Physics, 801 Leroy Place, Socorro, NM 87801 (United States)

    2016-02-10

    We survey 44 young stellar objects located near the edges of mid-IR-identified bubbles in CS (1–0) using the Green Bank Telescope. We detect emission in 18 sources, indicating young protostars that are good candidates for being triggered by the expansion of the bubble. We calculate CS column densities and abundances. Three sources show evidence of infall through non-Gaussian line-shapes. Two of these sources are associated with dark clouds and are promising candidates for further exploration of potential triggered star formation. We obtained on-the-fly maps in CS (1–0) of three sources, showing evidence of significant interactions between the sources and the surrounding environment.

  1. Rapid-Cycling Bubble-Chamber, details

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    Parts of the hydraulic expansion system of the Rapid-Cycling Bubble-Chamber (RCBC). RCBC was the largest of 3 rapid-cycling bubble-chambers (the others were LEBC and HOLEBC), used as target- and vertex-detectors within the European Hybrid Spectrometer (EHS) in the SPS North Area (EHN1). RCBC contained 250 l of liquid hydrogen and was located inside a 3 T superconducting magnet. It was designed for 30 expansions/s (100 times faster than BEBC), the system shown here allowed 50 expansions/s. RCBC operated from 1981 to 1983 for experiments NA21, NA22 and NA23 at a rate of 15 expansions/s, clocking up a total of over 4 million. In the rear, at left, is bearded Lucien Veillet; Augustin Didona is at the right. See also 8001009. The installation of the piston assembly in the RCBC chamber body is shown in the Annual Report 1980, p.65.

  2. Hydrodynamic models for slurry bubble column reactors

    Energy Technology Data Exchange (ETDEWEB)

    Gidaspow, D. [IIT Center, Chicago, IL (United States)

    1995-12-31

    The objective of this investigation is to convert a {open_quotes}learning gas-solid-liquid{close_quotes} fluidization model into a predictive design model. This model is capable of predicting local gas, liquid and solids hold-ups and the basic flow regimes: the uniform bubbling, the industrially practical churn-turbulent (bubble coalescence) and the slugging regimes. Current reactor models incorrectly assume that the gas and the particle hold-ups (volume fractions) are uniform in the reactor. They must be given in terms of empirical correlations determined under conditions that radically differ from reactor operation. In the proposed hydrodynamic approach these hold-ups are computed from separate phase momentum balances. Furthermore, the kinetic theory approach computes the high slurry viscosities from collisions of the catalyst particles. Thus particle rheology is not an input into the model.

  3. The Recent Financial Bubble: an Overview

    Directory of Open Access Journals (Sweden)

    Thalassinos E.

    2009-12-01

    Full Text Available The main aim of this paper is to analyse the recent financial crisis and to make recommendations how to handle it in the best possible way. Financial bubbles, since the great depression, have been analysed and some recommendations have been made taking into account the internationalization of the world economy which behaves like a domino. The recent financial crisis in the sub-prime mortgage market creates new problems in the world market with unforeseen continuances. Deflation has been referred to as a possible continuance after a financial bubble because often but not always deflation follows. Deflation often results in financial and economic crises. Financial and economic crises affect the architecture of the monetary system, while a change in the system may affect the role of the dollar, the euro and the yen.

  4. Hydrodynamics of ultra-relativistic bubble walls

    Directory of Open Access Journals (Sweden)

    Leonardo Leitao

    2016-04-01

    Full Text Available In cosmological first-order phase transitions, gravitational waves are generated by the collisions of bubble walls and by the bulk motions caused in the fluid. A sizeable signal may result from fast-moving walls. In this work we study the hydrodynamics associated to the fastest propagation modes, namely, ultra-relativistic detonations and runaway solutions. We compute the energy injected by the phase transition into the fluid and the energy which accumulates in the bubble walls. We provide analytic approximations and fits as functions of the net force acting on the wall, which can be readily evaluated for specific models. We also study the back-reaction of hydrodynamics on the wall motion, and we discuss the extrapolation of the friction force away from the ultra-relativistic limit. We use these results to estimate the gravitational wave signal from detonations and runaway walls.

  5. Bubble propagation on a rail: a concept for sorting bubbles by size.

    Science.gov (United States)

    Franco-Gómez, Andrés; Thompson, Alice B; Hazel, Andrew L; Juel, Anne

    2017-11-10

    We demonstrate experimentally that the introduction of a rail, a small height constriction, within the cross-section of a rectangular channel could be used as a robust passive sorting device in two-phase fluid flows. Single air bubbles carried within silicone oil are generally transported on one side of the rail. However, for flow rates marginally larger than a critical value, a narrow band of bubble sizes can propagate (stably) over the rail, while bubbles of other sizes segregate to the side of the rail. The width of this band of bubble sizes increases with flow rate and the size of the most stable bubble can be tuned by varying the rail width. We present a complementary theoretical analysis based on a depth-averaged theory, which is in qualitative agreement with the experiments. The theoretical study reveals that the mechanism relies on a non-trivial interaction between capillary and viscous forces that is fully dynamic, rather than being a simple modification of capillary static solutions.

  6. Sonoluminescence and dynamics of cavitation bubble populations in sulfuric acid.

    Science.gov (United States)

    Thiemann, Andrea; Holsteyns, Frank; Cairós, Carlos; Mettin, Robert

    2017-01-01

    The detailed link of liquid phase sonochemical reactions and bubble dynamics is still not sufficiently known. To further clarify this issue, we image sonoluminescence and bubble oscillations, translations, and shapes in an acoustic cavitation setup at 23kHz in sulfuric acid with dissolved sodium sulfate and xenon gas saturation. The colour of sonoluminescence varies in a way that emissions from excited non-volatile sodium atoms are prominently observed far from the acoustic horn emitter ("red region"), while such emissions are nearly absent close to the horn tip ("blue region"). High-speed images reveal the dynamics of distinct bubble populations that can partly be linked to the different emission regions. In particular, we see smaller strongly collapsing spherical bubbles within the blue region, while larger bubbles with a liquid jet during collapse dominate the red region. The jetting is induced by the fast bubble translation, which is a consequence of acoustic (Bjerknes) forces in the ultrasonic field. Numerical simulations with a spherical single bubble model reproduce quantitatively the volume oscillations and fast translation of the sodium emitting bubbles. Additionally, their intermittent stopping is explained by multistability in a hysteretic parameter range. The findings confirm the assumption that bubble deformations are responsible for pronounced sodium sonoluminescence. Notably the observed translation induced jetting appears to serve as efficient mixing mechanism of liquid into the heated gas phase of collapsing bubbles, thus potentially promoting liquid phase sonochemistry in general. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. The influence of bubbles on the perception carbonation bite.

    Directory of Open Access Journals (Sweden)

    Paul M Wise

    Full Text Available Although many people naively assume that the bite of carbonation is due to tactile stimulation of the oral cavity by bubbles, it has become increasingly clear that carbonation bite comes mainly from formation of carbonic acid in the oral mucosa. In Experiment 1, we asked whether bubbles were in fact required to perceive carbonation bite. Subjects rated oral pungency from several concentrations of carbonated water both at normal atmospheric pressure (at which bubbles could form and at 2.0 atmospheres pressure (at which bubbles did not form. Ratings of carbonation bite under the two pressure conditions were essentially identical, indicating that bubbles are not required for pungency. In Experiment 2, we created controlled streams of air bubbles around the tongue in mildly pungent CO2 solutions to determine how tactile stimulation from bubbles affects carbonation bite. Since innocuous sensations like light touch and cooling often suppress pain, we predicted that bubbles might reduce rated bite. Contrary to prediction, air bubbles flowing around the tongue significantly enhanced rated bite, without inducing perceived bite in blank (un-carbonated solutions. Accordingly, though bubbles are clearly not required for carbonation bite, they may well modulate perceived bite. More generally, the results show that innocuous tactile stimulation can enhance chemogenic pain. Possible physiological mechanisms are discussed.

  8. Period Doubling in Bubbling from a Submerged Nozzle

    Science.gov (United States)

    Dennis, Jordan; Grace, Laura; Lehman, Susan

    The timing of bubbles rising from a nozzle submerged in a viscous solution was measured to examine the period-doubling route to chaos in this system. A narrow nozzle was submerged in a mixture of water and glycerin, and nitrogen was supplied to the nozzle at a varying flow rate. The bubbles were detected using a laser and photodiode system; when the bubbles rise through the laser beam, they scatter the light so that the signal at the photodiode decreases. The period between bubbles as well as the duration of each bubble (a function of bubble size and bubble velocity) was determined, and examined as the nitrogen flow rate increased, for solutions with five different concentrations of glycerin. Bubbles were also recorded visually using a high-speed camera. Within the flow rates tested, we observed a bifurcation of the period to period-2 behavior for all solutions tested, and a further bifurcation to period-4 for all solutions except pure glycerin. The solution viscosity affected both the onset of the bifurcation and the precise bubble behavior during the bifurcation. Unusually, a short period/long period pair of bubbles recurring at a regular interval was sometimes observed in the low flow regime which is typically period-1, an observation which requires further investigation. Research supported by NSF DMR 1560093.

  9. Luminescence from cavitation bubbles deformed in uniform pressure gradients

    Science.gov (United States)

    Supponen, Outi; Obreschkow, Danail; Kobel, Philippe; Farhat, Mohamed

    2017-09-01

    Presented here are observations that demonstrate how the deformation of millimetric cavitation bubbles by a uniform pressure gradient quenches single-collapse luminescence. Our innovative measurement system captures a broad luminescence spectrum (wavelength range, 300-900 nm) from the individual collapses of laser-induced bubbles in water. By varying the bubble size, driving pressure, and perceived gravity level aboard parabolic flights, we probed the limit from aspherical to highly spherical bubble collapses. Luminescence was detected for bubbles of maximum radii within the previously uncovered range, R0=1.5 -6 mm, for laser-induced bubbles. The relative luminescence energy was found to rapidly decrease as a function of the bubble asymmetry quantified by the anisotropy parameter ζ , which is the dimensionless equivalent of the Kelvin impulse. As established previously, ζ also dictates the characteristic parameters of bubble-driven microjets. The threshold of ζ beyond which no luminescence is observed in our experiment closely coincides with the threshold where the microjets visibly pierce the bubble and drive a vapor jet during the rebound. The individual fitted blackbody temperatures range between Tlum=7000 and Tlum=11 500 K but do not show any clear trend as a function of ζ . Time-resolved measurements using a high-speed photodetector disclose multiple luminescence events at each bubble collapse. The averaged full width at half-maximum of the pulse is found to scale with R0 and to range between 10 and 20 ns.

  10. Soap-bubble Optimization of Gaits

    OpenAIRE

    Ramasamy, Suresh; Hatton, Ross L.

    2016-01-01

    In this paper, we present a geometric variational algorithm for optimizing the gaits of kinematic locomoting systems. The dynamics of this algorithm are analogous to the physics of a soap bubble, with the system's Lie bracket supplying an "inflation pressure" that is balanced by a "surface tension" term derived from a Riemannian metric on the system's shape space. We demonstrate this optimizer on a variety of system geometries (including Purcell's swimmer) and for optimization criteria that i...

  11. The Bern Infinitesimal Bubble Chamber (BIBC)

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    The chamber body was machined from a block of aluminium. The visible volume was cylindrical with 65 mm diameter and 35 mm depth. It was filled with propane or freon. It was meant as vertex detector in the search of short-lived particles. It was also used with in-line holography resulting in 8 µm bubble size and 9 cm depth of the field. See E. Ramseyer, B. Hahn and E. Hugentobler, Nucl. Instrum. Methods 201 (1982) 335.

  12. Expendable bubble tiltmeter for geophysical monitoring

    OpenAIRE

    Westphal, J. A.; Carr, M. A.; Miller, W. F.; Dzurisin, Daniel

    1983-01-01

    An unusually rugged highly sensitive and inexpensive bubble tiltmeter has been designed, tested, and built in quantity. These tiltmeters are presently used on two volcanoes and an Alaskan glacier, where they continuously monitor surface tilts of geological interest. This paper discusses the mechanical, thermal, and electric details of the meter, and illustrates its performance characteristics in both large ( > 10^(-4) radian) and small ( < 10^(-6) radian) tilt environments. The meter's ult...

  13. Measuring Bubble Expectations and Investor Confidence

    OpenAIRE

    Robert J. Shiller

    1999-01-01

    This paper presents evidence on attitude changes among investors in the US stock market. Two basic attitudes are explored: bubble expectations and investor confidence. Semiannual time-series indicators of these attitudes are presented for US stock market institutional investors based on questionnaire survey results 1989 1998, from surveys that I have derived in collaboration with Fumiko Kon-Ya and Yoshiro Tsutsui. Five different time-series indicators of whether there is among investors an ex...

  14. On the shape of giant soap bubbles

    NARCIS (Netherlands)

    Cohen, C.; Darbois Texier, B.; Reyssat, E.; Snoeijer, Jacobus Hendrikus; Quere, D.; Clanet, Christophe

    2017-01-01

    We study the effect of gravity on giant soap bubbles and show that it becomes dominant above the critical size ℓ=a2/e0ℓ=a2/e0, where e0e0 is the mean thickness of the soap film and a=γb/ρg−√a=γb/ρg is the capillary length ( γbγb stands for vapor–liquid surface tension, and ρρ stands for the liquid

  15. Influence of surfactant on gas bubble stability.

    Science.gov (United States)

    Hanwright, Jennifer; Zhou, James; Evans, Geoffrey M; Galvin, Kevin P

    2005-05-24

    Gas-bubble stability is achieved either by a reduction in the Laplace pressure or by a reduction in the permeability of the gas-liquid interface. Although insoluble surfactants have been shown definitively in many studies to lower the permeability of the gas-liquid interface and hence increase the resistance to interfacial mass transfer, remarkably little work has been done on the effects of soluble surfactants. An experimental system was developed to measure the effect of the soluble surfactant dodecyl trimethylammonium bromide on the desorption and absorption of carbon dioxide gas through a quiescent planar interface. The desorption experiments conformed to the model of non-steady-state molecular diffusion. The absorption experiments, however, produced an unexpected mass transfer mechanism, with surface renewal, probably because of instability in the density gradient formed by the carbon dioxide. In general, the soluble surfactant produced no measurable reduction in the rate of interfacial mass transfer for desorption or absorption. This finding is consistent with the conclusion of Caskey and Barlage that soluble surfactants produce a significantly lower resistance to interfacial mass transfer than do insoluble surfactants. The dynamic adsorption and desorption of the surfactant molecules at the gas-liquid interface creates short-term vacancies, which presumably permit the unrestricted transfer of the gas molecules through the interface. This surfactant exchange does not occur for insoluble surfactants. Gas bubbles formed in the presence of a high concentration of soluble surfactant were observed to dissolve completely, while those formed in the presence of the insoluble surfactant stearic acid did not dissolve easily, and persisted for very long periods. The interfacial concentration of stearic acid rises during bubble dissolution, as it is insoluble, and must eventually achieve full monolayer coverage and a state of compression, lowering the permeability of the

  16. The Gargamelle heavy liquid bubble chamber

    CERN Multimedia

    CERN PhotoLab

    1970-01-01

    This image shows the Gargamelle heavy liquid bubble chamber. It was used to detect particles in experiments at the PS between 1970 and 1976 before being moved to the SPS. In 1973, while working on the PS, it detected the first neutral current, an interaction vital to the electroweak theory. In 1978 a large fissure appeared in the body of the chamber and Gargamelle was stopped in 1979.

  17. Stochastic modelling for financial bubbles and policy

    OpenAIRE

    Fry, John

    2015-01-01

    In this paper, we draw upon the close relationship between statistical physics and mathematical finance to develop a suite of models for financial bubbles and crashes. By modifying previous approaches, we are able to derive novel analytical formulae for evaluation problems and for the expected timing of future change points. In particular, we help to explain why previous approaches have systematically overstated the timing of changes in market regime. The list of potential empirical applicati...

  18. Liquid-bubble Interaction under Surf Zone Breaking Waves

    Science.gov (United States)

    Derakhti, M.; Kirby, J. T., Jr.

    2014-12-01

    Liquid-bubble interaction, especially in complex two-phase bubbly flow under breaking waves, is still poorly understood. Derakhti and Kirby (2014a,b) have recently studied bubble entrainment and turbulence modulation by dispersed bubbles under isolated unsteady breaking waves along with extensive model verifications and convergence tests. In this presentation, we continue this examination with attention turned to the simulation of periodic surf zone breaking waves. In addition, the relative importance of preferential accumulation of dispersed bubbles in coherent vortex cores is investigated. Heavier-than-liquid particles, i.e. sediment, tend to accumulate in regions of high strain rate and avoid regions of intense vorticity. In contrast, lighter-than-liquid particles such as bubbles tend to congregate in vortical regions. We perform a three dimensional (3D) large-eddy simulation (LES) using a Navier-Stokes solver extended to incorporate entrained bubble populations, using an Eulerian-Eulerian formulation for the polydisperse bubble phase. The volume of fluid (VOF) method is used for free surface tracking. The model accounts for momentum exchange between dispersed bubbles and liquid phase as well as bubble-induced dissipation. We investigate the formation and evolution of breaking-induced turbulent coherent structures (BTCS) under both plunging and spilling periodic breaking waves as well as BTCS's role on the intermittent 3D distributions of bubble void fraction in the surf zone. We particularly examine the correlation between bubble void fractions and Q-criterion values to quantify this interaction. Also, the vertical transport of dispersed bubbles by downburst type coherent structures in the transition region is compared to that by obliquely descending eddies. All the results are summarized at different zones from outer to inner surf zone.

  19. Demonstrating the Importance of Bubbles and Viscosity on Volcanic Eruptions

    Science.gov (United States)

    Namiki, A.

    2005-12-01

    The behavior of bubbles (exsolved volatile from magma) and viscosity of magma are important parameters that influence volcanic eruptions. Exsolved volatiles increase the volume of magma and reduce its density so that magma has sufficient volume and buoyancy force to erupt. Volatiles exsolve through nucleation and growth by diffusion and bubbles can expand as pressure is reduced. The time scale of diffusion depends on the viscosity of surrounding magma, and the expansion time scale of a bubble is also depends on the viscosity of magma. These control the time scale for volume change. If bubbles segregate from magma and collapse, the magma might not able to expand sufficiently to erupt violently. Whether a bubble can segregate from the liquid part of magma is also depends on viscosity of magma. In this poster, I introduce a straightforward demonstration to show the importance of bubbles and viscosity of magma on volcanic eruptions. To make bubbles, I use baking soda (NaHCO3) and citric acid. Reaction between them generates carbon dioxide (CO2) to make bubbles. I make citric acid solution gel by using agar at the bottom of a transparent glass and pour baking soda disolved corn syrup on top of the agar. This situation is a model of basally heated magma chamber. When water disolved magma (baking soda disolved corn syrup) receives sufficient heat (citric acid) bubbles are generated. I can change viscosity of corn syrup by varying the concentration of water. This demonstration shows how viscosity controls the time scale of volume change of bubbly magma and the distribution of bubbles in the fluid. In addition it helps to understand the important physical processes in volcanic eruption: bubble nucleation, diffusion grows, expansion, and bubble driving convection. I will perform a live demonstration at the site of the poster.

  20. Bayesian Analysis of Bubbles in Asset Prices

    Directory of Open Access Journals (Sweden)

    Andras Fulop

    2017-10-01

    Full Text Available We develop a new model where the dynamic structure of the asset price, after the fundamental value is removed, is subject to two different regimes. One regime reflects the normal period where the asset price divided by the dividend is assumed to follow a mean-reverting process around a stochastic long run mean. The second regime reflects the bubble period with explosive behavior. Stochastic switches between two regimes and non-constant probabilities of exit from the bubble regime are both allowed. A Bayesian learning approach is employed to jointly estimate the latent states and the model parameters in real time. An important feature of our Bayesian method is that we are able to deal with parameter uncertainty and at the same time, to learn about the states and the parameters sequentially, allowing for real time model analysis. This feature is particularly useful for market surveillance. Analysis using simulated data reveals that our method has good power properties for detecting bubbles. Empirical analysis using price-dividend ratios of S&P500 highlights the advantages of our method.

  1. Characterization of polymers by bubble inflation

    DEFF Research Database (Denmark)

    Christensen, Jens Horslund; Rasmussen, Henrik K.; Kjær, Erik Michael

    1999-01-01

    In order to characterise materials using a simple and relative inexpensive method, the bubble inflation technique was modified. A polymer plate is clamped between a Teflon coated heating plate and a heated cylinder. By applying air through the heating plate the polymer membrane deforms into the c......In order to characterise materials using a simple and relative inexpensive method, the bubble inflation technique was modified. A polymer plate is clamped between a Teflon coated heating plate and a heated cylinder. By applying air through the heating plate the polymer membrane deforms...... into the cylinder. The top position of the membrane is monitored by fibreoptic sensors positioned in the cylinder. The pressure difference across the membrane is measured as well. The deformation in this inflation device is nonuniform and is only equal biaxial in the top of the deformed membrane. Due to this......, the response is modelled using a finite element method in 3D Cartesian coordinates. The K-BKZ constitutive equation is used to model the nonlinear properties of the material. Using linear viscoelastic properties from oscillatory shear measurements and measurements of the bubble inflation, estimation...

  2. BEBC, the Big European Bubble Chamber

    CERN Multimedia

    CERN PhotoLab

    1971-01-01

    The vessel of the Big European Bubble Chamber, BEBC, was installed at the beginning of the 1970s. The large stainless-steel vessel, measuring 3.7 metres in diameter and 4 metres in height, was filled with 35 cubic metres of liquid (hydrogen, deuterium or a neon-hydrogen mixture), whose sensitivity was regulated by means of a huge piston weighing 2 tonnes. During each expansion, the trajectories of the charged particles were marked by a trail of bubbles, where liquid reached boiling point as they passed through it. The first images were recorded in 1973 when BEBC, equipped with the largest superconducting magnet in service at the time, first received beam from the PS. In 1977, the bubble chamber was exposed to neutrino and hadron beams at higher energies of up to 450 GeV after the SPS came into operation. By the end of its active life in 1984, BEBC had delivered a total of 6.3 million photographs to 22 experiments devoted to neutrino or hadron physics. Around 600 scientists from some fifty laboratories through...

  3. Wrinkling in the deflation of elastic bubbles

    KAUST Repository

    Aumaitre, Elodie

    2013-03-01

    The protein hydrophobin HFBII self-assembles into very elastic films at the surface of water; these films wrinkle readily upon compression. We demonstrate and study this wrinkling instability in the context of non-planar interfaces by forming HFBII layers at the surface of bubbles whose interfaces are then compressed by deflation of the bubble. By varying the initial concentration of the hydrophobin solutions, we are able to show that buckling occurs at a critical packing fraction of protein molecules on the surface. Independent experiments show that at this packing fraction the interface has a finite positive surface tension, and not zero surface tension as is usually assumed at buckling. We attribute this non-zero wrinkling tension to the finite elasticity of these interfaces. We develop a simple geometrical model for the evolution of the wrinkle length with further deflation and show that wrinkles grow rapidly near the needle (used for deflation) towards the mid-plane of the bubble. This geometrical model yields predictions for the length of wrinkles in good agreement with experiments independently of the rheological properties of the adsorbed layer. © 2013 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.

  4. Bubbles of nothing and supersymmetric compactifications

    Energy Technology Data Exchange (ETDEWEB)

    Blanco-Pillado, Jose J. [IKERBASQUE, Basque Foundation for Science, 48011, Bilbao (Spain); Department of Theoretical Physics, University of the Basque Country UPV/EHU,48080 Bilbao (Spain); Shlaer, Benjamin [Department of Physics, University of Auckland,Private Bag 92019, Auckland (New Zealand); Institute of Cosmology, Department of Physics and Astronomy,Tufts University, Medford, MA 02155 (United States); Sousa, Kepa [Department of Theoretical Physics, University of the Basque Country UPV/EHU,48080 Bilbao (Spain); Instituto de Fisica Teorica UAM-CSIC, Universidad Autonoma de Madrid,Cantoblanco, 28049 Madrid (Spain); Urrestilla, Jon [Department of Theoretical Physics, University of the Basque Country UPV/EHU,48080 Bilbao (Spain)

    2016-10-03

    We investigate the non-perturbative stability of supersymmetric compactifications with respect to decay via a bubble of nothing. We show examples where this kind of instability is not prohibited by the spin structure, i.e., periodicity of fermions about the extra dimension. However, such “topologically unobstructed” cases do exhibit an extra-dimensional analog of the well-known Coleman-De Luccia suppression mechanism, which prohibits the decay of supersymmetric vacua. We demonstrate this explicitly in a four dimensional Abelian-Higgs toy model coupled to supergravity. The compactification of this model to M{sub 3}×S{sub 1} presents the possibility of vacua with different windings for the scalar field. Away from the supersymmetric limit, these states decay by the formation of a bubble of nothing, dressed with an Abelian-Higgs vortex. We show how, as one approaches the supersymmetric limit, the circumference of the topologically unobstructed bubble becomes infinite, thereby preventing the realization of this decay. This demonstrates the dynamical origin of the decay suppression, as opposed to the more familiar argument based on the spin structure. We conjecture that this is a generic mechanism that enforces stability of any topologically unobstructed supersymmetric compactification.

  5. Primitive mechanisms of trauma response: an evolutionary perspective on trauma-related disorders.

    Science.gov (United States)

    Baldwin, David V

    2013-09-01

    The symptoms we identify and the behaviors we recognize as defenses define which symptoms we see as trauma-related. Early conceptions of trauma-related disorders focused on physical signs of distress while current ones emphasize mental symptoms, but traumatizing experiences evoke psychobiological reactions. An evolutionary perspective presumes that psychophysical reactions to traumatizing events evolved to ensure survival. This theoretical review examines several primitive mechanisms (e.g., sensitization and dissolution) associated with responses to diverse stressors, from danger to life-threat. Some rapidly acquired symptoms form without conscious awareness because severe stresses can dysregulate mental and physical components within systems ensuring survival. Varied defensive options engage specialized and enduring psychophysical reactions; this allows for more adaptive responses to diverse threats. Thus, parasympathetically mediated defense states such as freeze or collapse increase trauma-related symptom variability. Comorbidity and symptom variability confuse those expecting mental rather than psychophysical responses to trauma, and active (sympathetically mediated flight and fight) rather than immobility defenses. Healthcare implications for stress research, clinical practice and diagnostic nosology stem from the broader evolutionary view. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Needle Thoracotomy in Trauma.

    Science.gov (United States)

    Rottenstreich, Misgav; Fay, Shmuel; Gendler, Sami; Klein, Yoram; Arkovitz, Marc; Rottenstreich, Amihai

    2015-12-01

    Tension pneumothorax is one of the leading causes of preventable death in trauma patients. Needle thoracotomy (NT) is the currently accepted first-line intervention but has not been well validated. In this review, we have critically discussed the evidence for NT procedure, re-examined the recommendations by the Advanced Trauma Life Support organization and investigated the safest and most effective way of NT. The current evidence to support the use of NT is limited. However, when used, it should be applied in the 2nd intercostal space at midclavicular line using a catheter length of at least 4.5 cm. Alternative measures should be studied for better prehospital management of tension pneumothorax. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.

  7. Maxillofacial trauma scoring systems.

    Science.gov (United States)

    Sahni, Vaibhav

    2016-07-01

    The changing complexity of maxillofacial fractures in recent years has created a situation where classical systems of classification of maxillofacial injuries fall short of defining trauma particularly that observed with high-velocity collisions where more than one region of the maxillofacial skeleton is affected. Trauma scoring systems designed specifically for the maxillofacial region are aimed to provide a more accurate assessment of the injury, its prognosis, the possible treatment outcomes, economics, length of hospital stay, and triage. The evolution and logic of such systems along with their merits and demerits are discussed. The author also proposes a new system to aid users in quickly and methodically choosing the system best suited to their needs without having to study a plethora of literature available in order to isolate their choice. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Videolaparoscopia no trauma abdominal

    Directory of Open Access Journals (Sweden)

    Átila Varela Velho

    Full Text Available A videolaparoscopia (VL vem contribuindo de forma crescente, para diagnóstico e terapêutica de várias afecções cirúrgicas abdominais, introduzindo profundas mudanças na cirurgia contemporânea. Esse avanço incorporou-se também às urgências traumáticas, fazendo parte da avaliação diagnóstica e, às vezes, da terapêutica do trauma abdominal. Os autores apresentam uma revisão concisa da literatura sobre a VL no trauma, atualizando o tema e discutindo os aspectos mais relevantes das indicações, limitações e complicações do método.

  9. Trauma Systems. An Era of Development

    OpenAIRE

    Lansink, K.W.W.

    2017-01-01

    The introduction of an inclusive trauma system in the Netherlands during last decade of the past century, has led to an improvement in Dutch trauma care. Eleven trauma regions were formed nationwide each surrounding a level I trauma center. All hospitals in a trauma region were assigned levels I, II or III, and are working together in a trauma network. Also part of the introduction of the inclusive trauma system was the regionalization of individual ambulance care and the introduction of mobi...

  10. Thromboembolic Complications Following Trauma

    Science.gov (United States)

    2009-12-01

    intracranial hemorrhage following hypertension and ischemia due to hypoperfusion during shock. Cerebrovas- cular injury is only one mechanism, and a...fracture, neurologic exam not explained by grain imaging, Horner’s syndrome , LeFort I or II fractures, skull-base fractures involving the foramen lacerum, or...into the study, and it again fails to represent the total trauma popu- lation. For example, skull fractures, intracranial injuries, and extremity

  11. ABDOMINAL TRAUMA- CLINICAL STUDY

    Directory of Open Access Journals (Sweden)

    Vanaja Ratnakumari Billa

    2017-08-01

    Full Text Available BACKGROUND In the recent times there has been increased incidence of abdominal trauma cases due to several causes. Quick and prompt intervention is needed to decrease the mortality of the patients. So we conducted a study to assess the cause and the management of abdominal trauma cases in our institution. The aim of this study was to know the incidence of blunt and penetrating injuries and their causes, age and sex incidence, importance of various investigations, mode of treatment offered and post-operative complications. To study the cause of death and evolve better management. MATERIALS AND METHODS The present study comprises of patients admitted to and operated in various surgical units in the Department of Surgery at Government General Hospital, attached to Guntur Medical College Guntur, from August 2014 to October 2016. RESULTS Increase incidence seen in age group 20-29 years (30%. Male predominance 77.5%. Mechanism of injury–road traffic accidents 65%. Isolated organ injury–colon and rectum 40%. Other associated injuries–chest injuries with rib fractures 7.5%. Complications–wound infection 17.5%. Duration of hospital stay 8–14 days. Bowel injury management–closure of perforation 84.6%. Resection anastomosis 15.38%. CONCLUSION Thorough clinical examination, diagnostic paracentesis, plain X-ray erect abdomen and ultrasound proved to be very helpful in the diagnosis of intra-abdominal injuries. Spleen is the commonest organ involved in blunt trauma and colon is the commonly injured organ in penetrating abdominal trauma, many patients have associated extremity and axial skeleton injuries. With advances in diagnosis and intensive care technologies, most patients of solid visceral injuries with hemodynamic stability can be managed conservatively. Surgical site infection is the most common complication following surgery. The mortality is high; reason might be patient reaching the hospital late, high incidence of postoperative septic

  12. The dynamics of underwater bubbles near deformable boundaries

    Science.gov (United States)

    Milligan, Charles Dean

    Bubble hydrodynamic simulations including re-entrant jet impact and penetration are performed using domain partitioning methods along with traditional boundary element techniques. By combining the new multi-subdomain scheme with the boundary conditions for jet impact and penetration presented by Zhang, Duncan and Chahine (1), continuous simulations of the jet impact and penetration process are achieved. The strategy is verified through comparisons with theoretical and numerical potential flow problems, and proves to be more stable than existing jet impact and penetration models (1). The fluid model is used to study bubble-bubble interactions and bubble-structure interaction phenomena. The fluid model is coupled to a nonlinear finite element code through fully nonlinear coupling equations. For the first time, stable fluid-structure interaction calculations with jet impact are performed. The method is used to simulate the interaction between a small explosion bubble and aluminum plates of different thicknesses. The results are compared with experimental results (2, 3), and the predicted bubble motions prior to and during jet penetration are in agreement with the measurements. In the experiments, secondary cavities form on the surface of the thinnest plate. The secondary cavitation is not rigorously modeled in the numerical scheme but reasonable agreement between predicted and measured plate strain was achieved. The simulations help identify the role of secondary cavitation in the interaction process. The multi-subdomain fluid model is also used to simulate the interaction between two explosion bubbles generated with a time delay between the two explosive detonations. The approach is verified through direct comparisons with experimental results (4, 5). The numerical model shows that when the time delay between the two detonations is small, the inertia of the fluid around each bubble is comparable, so the bubbles act as images of each other. For larger time delays

  13. Investigation on Effect of Gravity Level on Bubble Distribution and Liquid Turbulence Modification for Horizontal Channel Bubbly Flow

    Science.gov (United States)

    Pang, M. J.; Wei, J. J.; Yu, B.

    2017-08-01

    Bubbly flows in the horizontal channel or pipe are often seen in industrial engineering fields, so it is very necessary to fully understand hydrodynamics of horizontal bubbly flows so as to improve industrial efficiency and to design an efficient bubbly system. In this paper, in order to fully understand mechanisms of phase distribution and liquid-phase turbulence modulation in the horizontal channel bubbly flow, the influence of gravity level on both of them were investigated in detail with the developed Euler-Lagrange two-way coupling method. For the present investigation, the buoyance on bubbles in both sides of the channel always points to the corresponding wall in order to study the liquid-phase turbulence modulation by bubbles under the symmetric physical condition. The present investigation shows that the gravity level has the important influence on the wall-normal distribution of bubbles and the liquid-phase turbulence modulation; the higher the gravity level is, the more bubbles can overcome the wall-normal resistance to accumulate near the wall, and the more obvious the liquid-phase turbulence modulation is. It is also discovered that interphase forces on the bubbles are various along the wall-normal direction, which leads to the fact that the bubble located in different wall-normal places has a different wall-normal velocity.

  14. Imaging of laryngeal trauma

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Minerva, E-mail: Minerva.Becker@hcuge.ch [Department of Radiology, Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, 1211 Geneva 14 (Switzerland); Leuchter, Igor, E-mail: Igor.Leuchter@hcuge.ch [Department of Otorhinolaryngology and Cervico-facial Surgery, University Hospital of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211 Geneva 14 (Switzerland); Platon, Alexandra, E-mail: Alexandra.Platon@hcuge.ch [Department of Radiology, Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, 1211 Geneva 14 (Switzerland); Becker, Christoph D., E-mail: Christoph.Becker@hcuge.ch [Department of Radiology, Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, 1211 Geneva 14 (Switzerland); Dulguerov, Pavel, E-mail: Pavel.Dulguerov@hcuge.ch [Department of Otorhinolaryngology and Cervico-facial Surgery, University Hospital of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211 Geneva 14 (Switzerland); Varoquaux, Arthur, E-mail: Arthur.Varoquaux@hcuge.ch [Department of Radiology, Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, 1211 Geneva 14 (Switzerland)

    2014-01-15

    External laryngeal trauma is a rare but potentially life-threatening situation in the acutely injured patient. Trauma mechanism and magnitude, maximum focus of the applied force, and patient related factors, such as age and ossification of the laryngeal cartilages influence the spectrum of observed injuries. Their correct diagnosis and prompt management are paramount in order to avoid patient death or long-term impairment of breathing, swallowing and speaking. The current review provides a comprehensive approach to the radiologic interpretation of imaging studies performed in patients with suspected laryngeal injury. It describes the key anatomic structures that are relevant in laryngeal trauma and discusses the clinical role of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the acute emergency situation. The added value of two-dimensional multiplanar reconstructions (2D MPR), three-dimensional volume rendering (3D VR) and virtual endoscopy (VE) for the non-invasive evaluation of laryngeal injuries and for treatment planning is discussed. The clinical presentation, biomechanics of injury, diagnostic pitfalls and pearls, common and uncommon findings are reviewed with emphasis of fracture patterns, involvement of laryngeal joints, intra- and extralaryngeal soft tissue injuries, and complications seen in the acute emergency situation. The radiologic appearance of common and less common long-term sequelae, as well as treatment options are equally addressed.

  15. Imaging of laryngeal trauma.

    Science.gov (United States)

    Becker, Minerva; Leuchter, Igor; Platon, Alexandra; Becker, Christoph D; Dulguerov, Pavel; Varoquaux, Arthur

    2014-01-01

    External laryngeal trauma is a rare but potentially life-threatening situation in the acutely injured patient. Trauma mechanism and magnitude, maximum focus of the applied force, and patient related factors, such as age and ossification of the laryngeal cartilages influence the spectrum of observed injuries. Their correct diagnosis and prompt management are paramount in order to avoid patient death or long-term impairment of breathing, swallowing and speaking. The current review provides a comprehensive approach to the radiologic interpretation of imaging studies performed in patients with suspected laryngeal injury. It describes the key anatomic structures that are relevant in laryngeal trauma and discusses the clinical role of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the acute emergency situation. The added value of two-dimensional multiplanar reconstructions (2D MPR), three-dimensional volume rendering (3D VR) and virtual endoscopy (VE) for the non-invasive evaluation of laryngeal injuries and for treatment planning is discussed. The clinical presentation, biomechanics of injury, diagnostic pitfalls and pearls, common and uncommon findings are reviewed with emphasis of fracture patterns, involvement of laryngeal joints, intra- and extralaryngeal soft tissue injuries, and complications seen in the acute emergency situation. The radiologic appearance of common and less common long-term sequelae, as well as treatment options are equally addressed. Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  16. A Study of Drag Force in Isothermal Bubbly Flow

    Directory of Open Access Journals (Sweden)

    C. Li

    2009-12-01

    Full Text Available Driven by the extensive demands of simulating highly concentrated gas bubbly flows in many engineering fields, numerical studies have been performed to investigate the neighbouring effect of a swarm of bubbles on the interfacial drag forces. In this study, a novel drag coefficient correlation (Simonnet et al., 2007 in terms of local void fraction coupled with the population balance model based on average bubble number density (ABND has been implemented and compared with Ishii-Zuber densely distributed fluid particles drag model. The predicted local radial distributions of three primitive variables: gas void fraction, Sauter mean bubble diameter, and gas velocity, are validated against the experimental data of Hibiki et al. (2001. In general, satisfactory agreements between predicted and measured results are achieved by both drag force models. With additional consideration for closely packed bubbles, the latest coefficient model by Simonnet et al. (2007 shows considerably better performance in capturing the reduction of drag forces incurred by neighbouring bubbles.

  17. An apparatus to measure electrical charge of bubble swarms.

    Science.gov (United States)

    Uddin, S; Jin, L; Mirnezami, M; Finch, J A

    2013-01-01

    An apparatus has been developed to characterize bubble charge by measuring the swarm potential of gas bubbles. The technique allows in-process measurement of all system variables associated with bubble surface electrical charge: swarm potential, solution conductivity, gas holdup, pH and bubble size distribution. The method was validated by comparing with literature iso-electric point (iep) values. Bubble swarm potential was measured as a function of concentration and pH for a series of non-ionic surfactant frothers, ionic surfactant collectors and multivalent metal ions. Results showed good agreement with established theory and prior experimental findings. The setup is a step towards measurement of charge on flotation size range of bubble swarms. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Bubble nucleation from micro-crevices in a shear flow

    Science.gov (United States)

    Groß, T. F.; Bauer, J.; Ludwig, G.; Fernandez Rivas, D.; Pelz, P. F.

    2018-01-01

    The formation of gas bubbles at gas cavities located in walls bounding the flow occurs in many technical applications, but is usually hard to observe. Even though, the presence of a fluid flow undoubtedly affects the formation of bubbles, there are very few studies that take this fact into account. In the present paper new experimental results on bubble formation (diffusion-driven nucleation) from surface nuclei in a shear flow are presented. The observed gas-filled cavities are micrometre-sized blind holes etched in silicon substrates. We measure the frequency of bubble generation (nucleation rate), the size of the detaching bubbles and analyse the growth of the surface nuclei. The experimental findings support an extended understanding of bubble formation as a self-excited cyclic process and can serve as validation data for analytical and numerical models.

  19. Bubble migration in a rotating, liquid-filled sphere

    Science.gov (United States)

    Annamalai, P.; Subramanian, R. S.; Cole, R.

    1982-01-01

    Results and analysis of ground-based experiments performed to aid in designing experiments on the behavior of bubbles in a rotating liquid body on board the Shuttle in free fall are presented. Spherical shells filled with silicone oil containing a small gas bubble were spun and filmed by high speed motion picture photography. The rotation of the shell and the trajectory of the bubble motion were recorded and the film was exposed to a motion analyzer connected to a keypunch. The analyzer measured Cartesian coordinates as well as angle, frame number, and rotation rate. Optical correction equations were employed to determine the apparent bubble trajectory relative to an inertial frame of reference. An analytical model for the bubble motion was defined, yielding predictions of velocity and position at different times. Rotation of the fluid container is concluded to aid in centering the bubbles.

  20. The Morphology of Equatorial Plasma Bubbles – a review

    Directory of Open Access Journals (Sweden)

    Hyosub Kil

    2015-03-01

    Full Text Available Plasma bubbles that occur in the equatorial F-region make up one of the most distinguishing phenomena in the ionosphere. Bubbles represent plasma depletions with respect to the background ionosphere, and are the major source of electron density irregularities in the equatorial F-region. Such bubbles are seen as plasma depletion holes (in situ satellite observations, vertical plumes (radar observations, and emission-depletion bands elongated in the north-south direction (optical observations. However, no technique can observe the whole three-dimensional structure of a bubble. Various aspects of bubbles identified using different techniques indicate that a bubble has a “shell” structure. This paper reviews the development of the concepts of “bubble” and “shell” in this context.

  1. The equilibrium shape of bubbles on curved interfaces

    Science.gov (United States)

    Bird, James; Poe, Daniel; Walls, Peter

    2016-11-01

    The equilibrium shape for a bubble resting at a free surface depends on a balance of hydrostatic and capillary forces, with the smallest bubbles approximating a sphere and a hemisphere for the largest. This shape has been shown to be important to several processes ranging from gas transfer across the thin film cap to the production of jet droplets. Past works calculating the equilibrium shape assume that the interface is flat. However, there are instances where the curvature of the boundary may be comparable to the bubble itself. For example, a bubble bursting on the surface of a rain droplet. Here we relax the assumption of a flat interface and extend the classic bubble shape calculations to account for a curved interface boundary. An understanding of the extent of this deformation and the precise equilibrium bubble shape is important to applications in fields ranging from air-sea exchange to combustion dynamics. We acknowledge financial support from NSF Grant No. 1351466.

  2. Bubbles Outside the Plume During the LUMINY Wind-Wave Experiment

    NARCIS (Netherlands)

    Leeuw, G. de; Leifer, I.

    2002-01-01

    Since many bubble-mediated processes are size dependent, it is often necessary to characterize the bubble distribution over the full size spectrum. For example, in regards to bubble-mediated gas transfer, small bubbles are important for insoluble gases like helium, while large bubbles are important

  3. THE INFLUENCE OF GAS-DENSITY AND LIQUID PROPERTIES ON BUBBLE BREAKUP

    NARCIS (Netherlands)

    WILKINSON, PM; VANSCHAYK, A; SPRONKEN, JPM; VANDIERENDONCK, LL

    On the basis of a literature review of bubble breakup experiments, it is demonstrated that both liquid viscosity and surface tension have an influence on bubble stability and, thus, bubble breakup, for small as well as large bubbles. Possible influences of the gas properties on bubble breakup have

  4. CFD – facilitated Prognosis of Bubble Bed Bioreactor Performance Based on Bubble Swarms Oscillation Analysis

    OpenAIRE

    Vlaev, S. D.; Staykov, P.; Fialova, M.

    2009-01-01

    Bubble column reactors are widely used as gas-liquid and gas liquid-solid contactors in biotechnology applications. A basic issue in biotechnology is oxygen availability related to gas hold-up distribution, since aerobic bioprocessing depends on the dissolved oxygen substrate. The aim of this study is to analyze oxygen availability in bubble column bioreactors in terms of specific spatial and temporal gas-liquid flow. 3D CFD simulation is used to simulate the dispersed gas-liquid flow field o...

  5. Bubbles are more than you think - The Center for Information and Bubble Studies

    DEFF Research Database (Denmark)

    Hendricks, Vincent Fella

    2016-01-01

    in social media, trading likes for likes all the time, and without much market research. Of course, social media is awash with what the finance world would call liquidity – there is no shortage of likes, upvotes, posts and retweets. However, too much liquidity can poison a financial market, leading prices...... to inflate beyond their fundamental value – what we call a bubble. Furthermore, it can possibly poison a market in which we invest opinions and expressions rather than money. By this means, the pivotal aim of the Center for Information and Bubble Studies (CIBS) is to uncover the structure and dynamics...

  6. Renal function after trauma.

    Science.gov (United States)

    World, Michael J

    2013-06-01

    The lack of need for immediate renal replacement treatment for military trauma victims suggests that the current policy of restricting operational deployment of those Service personnel with active inflammatory renal disease and significantly impaired renal function, combined with good prehospital care for all trauma casualties, is probably correct. No published estimates of renal function in civilian or military trauma victims in the earliest period following injury have been retrieved. The purpose of the present retrospective study was to assess the renal function of military trauma victims on arrival in the Emergency Department of the field hospital. The case records of 287 military trauma casualties with severe injury (New Injury Severity Score, NISS≥16) were retrospectively reviewed to assess renal function by calculating estimated glomerular filtration rate (eGFR) using the serum creatine concentration obtained immediately on arrival in the Emergency Department of the field hospitals in Iraq and Afghanistan, 2005-2009. Correlations were attempted between eGFR and other clinical and laboratory variables. Hospital case notes recording management following repatriation were retrieved in 221/287 (77%) cases. None had required immediate renal support in the field. Serum creatine concentration on arrival in the field hospital with demographic data permitting calculation of eGFR was recorded in 158 cases. Median eGFR=76 ml/min/1.73 m(2) (range=43-144). Statistically significant correlations were found among eGFR and pulse rate (r=-0.3, p=0.0002), body temperature (r=0.24, p=0.01) and mean arterial pressure (r=0.2, p=0.02). No statistically significant correlation was found among eGFR and NISS, white cell count, or respiration rate. A stepwise multivariate regression analysis of 106 cases suggested that the best combination of clinical observations to predict renal function were pulse rate and body temperature but the prediction was overoptimistic at lower e

  7. Bubble-Induced Endothelial Microparticles Promote Endothelial Dysfunction.

    Science.gov (United States)

    Yu, Xuhua; Xu, Jiajun; Huang, Guoyang; Zhang, Kun; Qing, Long; Liu, Wenwu; Xu, Weigang

    2017-01-01

    Decompression sickness is a systemic pathophysiological process caused by bubbles and endothelial microparticles (EMPs) are established markers reflecting competency of endothelial function and vascular biology. Here, we investigated the effects of bubble-induced EMPs on endothelial cells in vitro and vivo. Rat pulmonary microvascular endothelial cells (PMVECs) were isolated and stimulated by bubbles and bubble-induced EMPs were collected and incubated with normal PMVECs in vitro. Cell viability and apoptosis were detected using Cell Counting Kit-8 assay and Annexin V FITC/PI double staining, respectively. Cell permeability and pro-inflammatory cytokines were determined by electric cell substrate impedance sensing and enzyme-linked immunosorbent assay, respectively. Intracellular nitric oxide and reactive oxygen species production were analyzed microscopically. In vivo study, bubble-induced EMPs were intravenously injected to the rats and soluble thrombomodulin, intercellular adhesion molecule 1, and vascullar adhesion molecule 1 were involved in evaluating endothelial dysfunction. In our study, bubble stimulus resulted in a significant increase of EMPs release by 3 fold. Bubble-induced EMPs significantly decreased cell viability and increased cell apoptosis. Moreover, bubble-induced EMPs induced abnormal increase of cell permeability and over-expression of pro-inflammatory cytokines. Intracellular ROS production increased while NO production decreased. These negative effects caused by bubble-induced EMPs were remarkably suppressed when EMPs pretreated with surfactant FSN-100. Finally, intravenous injection of bubble-induced EMPs caused elevations of soluble thrombomodulin and pro-inflammatory cytokines in the circulation. Altogether, our results demonstrated that bubble-induced EMPs can mediate endothelial dysfunction in vitro and vivo, which can be attenuated by EMPs abatement strategy. These data expanded our horizon of the detrimental effects of bubble

  8. A biophysical vascular bubble model for devising decompression procedures.

    Science.gov (United States)

    Arieli, Ran; Marmur, Abraham

    2017-03-01

    Vascular bubble models, which present a realistic biophysical approach, hold great promise for devising suitable diver decompression procedures. Nanobubbles were found to nucleate on a flat hydrophobic surface, expanding to form bubbles after decompression. Such active hydrophobic spots (AHS) were formed from lung surfactants on the luminal aspect of ovine blood vessels. Many of the phenomena observed in these bubbling vessels correlated with those known to occur in diving. On the basis of our previous studies, which proposed a new model for the formation of arterial bubbles, we now suggest the biophysical model presented herein. There are two phases of bubble expansion after decompression. The first is an extended initiation phase, during which nanobubbles are transformed into gas micronuclei and begin to expand. The second, shorter phase is one of simple diffusion-driven growth, the inert gas tension in the blood remaining almost constant during bubble expansion. Detachment of the bubble occurs when its buoyancy exceeds the intermembrane force. Three mechanisms underlying the appearance of arterial bubbles should be considered: patent foramen ovale, intrapulmonary arteriovenous anastomoses, and the evolution of bubbles in the distal arteries with preference for the spinal cord. Other parameters that may be quantified include age, acclimation, distribution of bubble volume, AHS, individual sensitivity, and frequency of bubble formation. We believe that the vascular bubble model we propose adheres more closely to proven physiological processes. Its predictability may therefore be higher than other models, with appropriate adjustments for decompression illness (DCI) data. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  9. Dynamics of bubble rising at small Reynolds numbers

    Directory of Open Access Journals (Sweden)

    Arkhipov Vladimir

    2015-01-01

    Full Text Available Results of experimental study of a single spherical bubble rising in the non-stationary regime in a viscous liquid (with and without surfactant at small Reynolds numbers Re<1 have been presented. Improved empirical correlations for drag coefficient of the bubble rising with and without surfactant in the stationary regime have been obtained. Influence of nonstationary effects on the dynamics of bubble rising has been analyzed.

  10. Bubble-Induced Endothelial Microparticles Promote Endothelial Dysfunction.

    Directory of Open Access Journals (Sweden)

    Xuhua Yu

    Full Text Available Decompression sickness is a systemic pathophysiological process caused by bubbles and endothelial microparticles (EMPs are established markers reflecting competency of endothelial function and vascular biology. Here, we investigated the effects of bubble-induced EMPs on endothelial cells in vitro and vivo. Rat pulmonary microvascular endothelial cells (PMVECs were isolated and stimulated by bubbles and bubble-induced EMPs were collected and incubated with normal PMVECs in vitro. Cell viability and apoptosis were detected using Cell Counting Kit-8 assay and Annexin V FITC/PI double staining, respectively. Cell permeability and pro-inflammatory cytokines were determined by electric cell substrate impedance sensing and enzyme-linked immunosorbent assay, respectively. Intracellular nitric oxide and reactive oxygen species production were analyzed microscopically. In vivo study, bubble-induced EMPs were intravenously injected to the rats and soluble thrombomodulin, intercellular adhesion molecule 1, and vascullar adhesion molecule 1 were involved in evaluating endothelial dysfunction. In our study, bubble stimulus resulted in a significant increase of EMPs release by 3 fold. Bubble-induced EMPs significantly decreased cell viability and increased cell apoptosis. Moreover, bubble-induced EMPs induced abnormal increase of cell permeability and over-expression of pro-inflammatory cytokines. Intracellular ROS production increased while NO production decreased. These negative effects caused by bubble-induced EMPs were remarkably suppressed when EMPs pretreated with surfactant FSN-100. Finally, intravenous injection of bubble-induced EMPs caused elevations of soluble thrombomodulin and pro-inflammatory cytokines in the circulation. Altogether, our results demonstrated that bubble-induced EMPs can mediate endothelial dysfunction in vitro and vivo, which can be attenuated by EMPs abatement strategy. These data expanded our horizon of the detrimental effects

  11. Shape Oscillations of Gas Bubbles With Newtonian Interfacial Rheological Properties

    Science.gov (United States)

    Nadim, Ali

    1996-01-01

    The oscillation frequency and damping rate for small-amplitude axisymmetric shape modes of a gas bubble in an ideal liquid are obtained, in the limit when the bubble interface possesses Newtonian interfacial rheology with constant surface shear and dilatational viscosities. Such results permit the latter surface properties to be measured by analyzing experimental data on frequency shift and damping rate of specific shape modes of suspended bubbles in the presence of surfactants.

  12. Study Of Bubble-Count Measurement Of Surface Tension

    Science.gov (United States)

    Nishioka, Gary M.; Berg, James I.

    1993-01-01

    Report presents study of bubble-count method of measurement of surface or interfacial tension of liquids. In method, gas or liquid pumped at known rate along capillary tube. One end of tube open and immersed in liquid that wets tube. Pumped gas or liquid forms bubbles, detaching themselves from immersed open end of tube, and one measures average period, Pi, for formation and detachment of bubbles.

  13. Date Stamping Bubbles in Real Estate Investment Trusts

    OpenAIRE

    Escobari, Diego; Jafarinejad, Mohammad

    2015-01-01

    We test for the existence of single and multiple bubble periods in four Real Estate Investment Trust (REIT) indices using the Supremum Augmented Dickey-Fuller (SADF) and the Generalized SADF. These methods allow us to estimate the beginning and the end of bubble periods. Our results provide statistically significant evidence of speculative bubbles in the REIT index and its three components: Equity, Mortgage and Hybrid REITs. These results may be valuable for real estate financial managers and...

  14. Modeling of bubble dynamics in relation to medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Amendt, P.A.; London, R.A. [Lawrence Livermore National Lab., CA (United States); Strauss, M. [California Univ., Davis, CA (United States)]|[Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev] [and others

    1997-03-12

    In various pulsed-laser medical applications, strong stress transients can be generated in advance of vapor bubble formation. To better understand the evolution of stress transients and subsequent formation of vapor bubbles, two-dimensional simulations are presented in channel or cylindrical geometry with the LATIS (LAser TISsue) computer code. Differences with one-dimensional modeling are explored, and simulated experimental conditions for vapor bubble generation are presented and compared with data. 22 refs., 8 figs.

  15. Soap bubbles: two years old and sixty centimeters in diameter.

    Science.gov (United States)

    Grosse, A V

    1969-04-18

    Soap bubbles of long life (over 2 years) and large size (over 60 centimeters in diameter, 100 liters volume) have been produced from bubble solutions improved by the addition of water-soluble synthetic organic polymers such as polyvinyl alcohol or polyoxyethylene. The natural life can be defined as the time it takes for the bubble, if left undisturbed, to contract from the original size to a flat film.

  16. Bubble Impingement and the Mechanisms of Heat Transfer

    OpenAIRE

    Robinson, Anthony; ALBADAWI, ABDULALEEM; MURRAY, DARINA

    2014-01-01

    PUBLISHED Heat transfer augmentation resulting from the effects of two phase flow can play a significant role in convective cooling applications. To date, the interaction between a rising gas bubble impinging on a heated horizontal surface has received limited attention. Available research has focused on bubble dynamics and the associated heat transfer has not been reported. To address this, this study investigates the effect of a single bubble impinging on a heated horizontal surface. Loc...

  17. From Rising Bubble to RNA/DNA and Bacteria

    Science.gov (United States)

    Marks, Roman; Cieszyńska, Agata; Wereszka, Marzena; Borkowski, Wojciech

    2017-04-01

    In this study we have focused on the movement of rising bubbles in a salty water body. Experiments reviled that free buoyancy movement of bubbles forces displacement of ions, located on the outer side of the bubble wall curvatures. During the short moment of bubble passage, all ions in the vicinity of rising bubble, are separated into anions that are gathered on the bubble upper half sphere and cations that slip along the bottom concave half-sphere of a bubble and develop a sub-bubble vortex. The principle of ions separation bases on the differences in displacement resistance. In this way, relatively heavier and larger, thus more resistant to displacement anions are gathered on the rising bubble upper half sphere, while smaller and lighter cations are assembled on the bottom half sphere and within the sub-bubble vortex. The acceleration of motion generates antiparallel rotary of bi-ionic domains, what implies that anions rotate in clockwise (CW) and cationic in counter-clockwise (CCW) direction. Then, both rotational systems may undergo splicing and extreme condensing by bi-pirouette narrowing of rotary. It is suggested that such double helix motion of bi-ionic domains creates RNA/DNA molecules. Finally, when the bubble reaches the water surface it burst and the preprocessed RNA/DNA matter is ejected into the droplets. Since that stage, droplet is suspended in positively charged troposphere, thus the cationic domain is located in the droplet center, whilst negative ions are attracted to configure the outer areola. According to above, the present study implies that the rising bubbles in salty waters may incept synergistic processing of matter resulting in its rotational/spherical organization that led to assembly of RNA/DNA molecules and bacteria cells.

  18. Compressibility of a translating bubble in an oscillating pressure field

    Science.gov (United States)

    Watts, R. G.; Hsu, Y.-Y.

    1974-01-01

    The response of a single translating vapor-gas bubble to a sinusoidal pressure variation is analyzed analytically and experimentally. The bubble is assumed to move in an infinite liquid with a constant translational velocity. Bubbles are assumed to consist of saturated vapor and a noncondensible gas. The experimental results are in the low frequency range with no noncondensible gas present, although the theory is more general. Agreement between experiment and theory is satisfactory.

  19. Bubble coalescence dynamics and supersaturation in electrolytic gas evolution

    Energy Technology Data Exchange (ETDEWEB)

    Stover, R.L. [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering]|[Lawrence Berkeley National Lab., CA (United States). Energy and Environment Div.

    1996-08-01

    The apparatus and procedures developed in this research permit the observation of electrolytic bubble coalescence, which heretofore has not been possible. The influence of bubble size, electrolyte viscosity, surface tension, gas type, and pH on bubble coalescence was examined. The Navier-Stokes equations with free surface boundary conditions were solved numerically for the full range of experimental variables that were examined. Based on this study, the following mechanism for bubble coalescence emerges: when two gas bubbles coalesce, the surface energy decreases as the curvature and surface area of the resultant bubble decrease, and the energy is imparted into the surrounding liquid. The initial motion is driven by the surface tension and slowed by the inertia and viscosity of the surrounding fluid. The initial velocity of the interface is approximately proportional to the square root of the surface tension and inversely proportional to the square root of the bubble radius. Fluid inertia sustains the oblate/prolate oscillations of the resultant bubble. The period of the oscillations varies with the bubble radius raised to the 3/2 power and inversely with the square root of the surface tension. Viscous resistance dampens the oscillations at a rate proportional to the viscosity and inversely proportional to the square of the bubble radius. The numerical simulations were consistent with most of the experimental results. The differences between the computed and measured saddle point decelerations and periods suggest that the surface tension in the experiments may have changed during each run. By adjusting the surface tension in the simulation, a good fit was obtained for the 150-{micro}m diameter bubbles. The simulations fit the experiments on larger bubbles with very little adjustment of surface tension. A more focused analysis should be done to elucidate the phenomena that occur in the receding liquid film immediately following rupture.

  20. Experiments performed with bubbly flow in vertical pipes at different flow conditions covering the transition region: simulation by coupling Eulerian, Lagrangian and 3D random walks models

    Science.gov (United States)

    Muñoz-Cobo, José; Chiva, Sergio; El Aziz Essa, Mohamed; Mendes, Santos

    2012-08-01

    Two phase flow experiments with different superficial velocities of gas and water were performed in a vertical upward isothermal cocurrent air-water flow column with conditions ranging from bubbly flow, with very low void fraction, to transition flow with some cap and slug bubbles and void fractions around 25%. The superficial velocities of the liquid and the gas phases were varied from 0.5 to 3 m/s and from 0 to 0.6 m/s, respectively. Also to check the effect of changing the surface tension on the previous experiments small amounts of 1-butanol were added to the water. These amounts range from 9 to 75 ppm and change the surface tension. This study is interesting because in real cases the surface tension of the water diminishes with temperature, and with this kind of experiments we can study indirectly the effect of changing the temperature on the void fraction distribution. The following axial and radial distributions were measured in all these experiments: void fraction, interfacial area concentration, interfacial velocity, Sauter mean diameter and turbulence intensity. The range of values of the gas superficial velocities in these experiments covered the range from bubbly flow to the transition to cap/slug flow. Also with transition flow conditions we distinguish two groups of bubbles in the experiments, the small spherical bubbles and the cap/slug bubbles. Special interest was devoted to the transition region from bubbly to cap/slug flow; the goal was to understand the physical phenomena that take place during this transition A set of numerical simulations of some of these experiments for bubbly flow conditions has been performed by coupling a Lagrangian code, that tracks the three dimensional motion of the individual bubbles in cylindrical coordinates inside the field of the carrier liquid, to an Eulerian model that computes the magnitudes of continuous phase and to a 3D random walk model that takes on account the fluctuation in the velocity field of the