Science.gov

Sample records for re-entry

  1. Project Re-Entry.

    ERIC Educational Resources Information Center

    Tri-County Opportunities Industrialization Center, Inc., Harrisburg, PA.

    Project Re-Entry was a follow-up study of the status of more than 5,000 former students of the Tri-County Opportunities Industrialization Center (OIC) in Harrisburg, Pennsylvania, who either never completed the entire General Educational Development (GED) test battery or completed the entire GED battery but still lacked enough points to earn a GED…

  2. GOCE Re-Entry Campaign

    NASA Astrophysics Data System (ADS)

    Bastida, B.; Flohrer, T.; Lemmens, S.; Krag, H.

    2015-03-01

    Every year ESA, through the Space Debris Office, participates to an Inter-Agency Space Debris Coordination Committee (IADC) Re-entry Test Campaign.. For the campaign of 2013, ESA’s proposal to select GOCE's re-entry was accepted. The campaign opened on the 21st October 2013 after fuel depletion of the drag-compensating ion propulsion. GOCE was expected to enter into a phase of attitude-controlled fine-pointing mode (FPM) until the attitude controllers would be unable to cope with the atmospheric torques and then the satellite would enter in a phase of fully uncontrolled flight. In this paper, we present the evolution of ESA’s daily predictions on the re-entry epoch using different sources of orbital information. The uncertainties on the spacecraft operability (i.e. the physical limits of the attitude controller) led to a non-standard re-entry scenario were different attitudes had to be considered (instead of the commonly assumed random tumbling mode case that is used whenever no information on the physical properties of a re-entering object is available). A daily assessment of the status, in coordination with the flight control team, was required and implied a continuous update on the predicted failure point of the attitude controller. This in turn imposed the need for considering an asymmetric re-entry window. These operation-bound uncertainties were simulated to predict the attitude evolution after failure at different altitudes and their effects evaluated to be taken into account for the re-entry predictions. We present ESA’s re-entry prediction activities for GOCE, internally, and within the IADC, and address specific technical aspects and challenges for re-entry predictions, which are related to the expected and occurred attitude of GOCE during the final re-entry phase.

  3. Re-entry Experiment Launch

    NASA Image and Video Library

    On August 10, 2009, NASA successfully launched the Inflatable Re-entry Vehicle Experiment (IRVE) and proved that spacecraft can use inflatable heat shields to reduce speed and provide protection du...

  4. Re-entry residency training

    PubMed Central

    Jamieson, Jean L.; Webber, Eric M.; Sivertz, Kristin S.

    2010-01-01

    ABSTRACT OBJECTIVE To identify and quantify the reasons general practitioners and family physicians consider retraining and their reasons for not pursuing further training. DESIGN Population-based mailed survey. SETTING British Columbia. PARTICIPANTS Family physicians and general practitioners identified by the College of Physicians and Surgeons of British Columbia. MAIN OUTCOME MEASURES Practising physicians’ level of awareness of the University of British Columbia’s re-entry training program, the number and demographic characteristics of those who had considered retraining, their specialties of interest, and the barriers and possible inducements to retraining. RESULTS Only half of the survey respondents were aware of the re-entry training program at the University of British Columbia. A small but substantial number of practising general practitioners and family physicians were interested in taking specialty training from the Royal College of Physicians and Surgeons of Canada. While several training programs were particularly popular (ie, anesthesia and psychiatry—18.5% of respondents for each), almost every specialty training program was mentioned. Physicians identified the length and hours of training, financial issues, family issues, and the need for relocation as obstacles to retraining. The availability of part-time training, regional training, and return-of-service financial assistance were all identified as potential inducements. CONCLUSION To meet the needs of practising physicians, re-entry training programs will need to consider flexibility, where feasible, with regard to choice of specialty, intensity, and location of postgraduate training. PMID:20547505

  5. Preventing re-entry to foster care.

    PubMed

    Carnochan, Sarah; Rizik-Baer, Daniel; Austin, Michael J

    2013-01-01

    Re-entry to foster care generally refers to circumstances in which children who have been discharged from foster care to be reunified with their family of origin, adopted, or provided kinship guardianship are returned to foster care. In the context of the federal performance measurement system, re-entry refers specifically to a return to foster care following an unsuccessful reunification. The federal Children and Family Services Review measures re-entry to foster care with a single indicator, called the permanency of reunification indicator, one of four indicators comprising the reunification composite measure. This review focuses on research related to the re-entry indicator, including the characteristics of children, caregivers and families, as well as case and child welfare services that are associated with a higher or lower risk of re-entry to foster care. Promising post-reunification services designed to prevent re-entry to foster care are described.

  6. Well engineering for re-entry operations

    SciTech Connect

    1996-10-01

    Oil and gas operators are constantly looking at their existing assets for ways to increase their value. Several operators consider a re-entry program as the principle leveraging technology in strategic acquisitions. Much of the current re-entry operations effort targets the longer reach sidetrack and multilateral well markets. The key to this effort, whether it involves coiled tubing drilling, short radius drilling or multilateral well technologies, is re-entry well engineering. The engineer evaluating a re-entry prospect must apply significant levels of reservoir engineering, rock mechanics, completion engineering and drilling engineering to properly design the well and develop successful procedures. Re-entry drilling means that the operator is working with proven or probable reserves. Completion design and engineering are the most important aspects of well design once the target has been selected. Ultimately, the completion design selected will dictate the type of re-entry program: slot recovery, drilling out below the current casing shoe, or section milling and whipstock sidetracking. It can also dictate the principle aspects of the drilling program. The acceptable wellbore inclination build rates (dogleg severity), wellbore length, and drilling fluid selection are commonly influenced and even dictated by the completion design. These factors are discussed.

  7. Aerodynamic design of a re-entry capsule for high-speed manned re-entry

    NASA Astrophysics Data System (ADS)

    Chen, Bingyan; Zhan, Huiling; Zhou, Weijiang

    2015-01-01

    Aerodynamic configuration of the capsule for manned re-entry at the second cosmic speed requires a relatively higher lift-to-drag ratio compared to the configuration for manned re-entry at the first cosmic speed. The present capsule configurations with high lift-to-drag ratio, for instance, the Apollo and the Orion, have secondary statically stable trim points, which is highly undesirable since it would cause disastrous result once the vehicle flies at the secondary trim point during re-entry. In the present study, effective design methodology for improving the monostability characteristics of re-entry capsules without compromising the lift-to-drag ratio is revealed based on flow field characteristics analysis. As a result, aerodynamic configuration design of a capsule with high lift-to-drag ratio and monostable characteristics is proposed. And the aerodynamic characteristics of the capsule ranging from subsonic to hypersonic speed are predicted by numerical simulations.

  8. Assessment of the ATV-1 Re-Entry Observation Campaign for Future Re-Entry Missions

    NASA Astrophysics Data System (ADS)

    Lips, T.; Lohle, S.; Marynowsky, T.; Rees, D.; Stenbeak-Nielsen, H. C.; Beks, M. L.; Hatton, J.

    2010-09-01

    This paper summarizes the midterm results of the currently ongoing ESA study “Assessment of the ATV-1 Reentry Observation Campaign for Future Re-entry Missions”. The primary objective of this study is to investigate the data obtained during a joint ESA/NASA airborne observation campaign of the destructive re-entry of ATV-1 Jules Verne which occurred on September 29, 2008. The presented results are focused on spectroscopic fragment characterization(material identification), frame-by-frame fragment tracking(manual and automatic) for various video recordings, 3D triangulation of the tracked fragments, and fragment propagation until complete demise or ground impact, including the actual size and location of the ATV-1 debris footprint. Fragment propagation analyses comprise also the derivation of aerodynamic fragment properties and potential delta velocities. These parameters are of high importance for the re-entry safety analysis for ATV-2 Johannes Kepler.

  9. Automated Re-Entry System using FNPEG

    NASA Technical Reports Server (NTRS)

    Johnson, Wyatt R.; Lu, Ping; Stachowiak, Susan J.

    2017-01-01

    This paper discusses the implementation and simulated performance of the FNPEG (Fully Numerical Predictor-corrector Entry Guidance) algorithm into GNC FSW (Guidance, Navigation, and Control Flight Software) for use in an autonomous re-entry vehicle. A few modifications to FNPEG are discussed that result in computational savings -- a change to the state propagator, and a modification to cross-range lateral logic. Finally, some Monte Carlo results are presented using a representative vehicle in both a high-fidelity 6-DOF (degree-of-freedom) sim as well as in a 3-DOF sim for independent validation.

  10. The X-37 Demonstrator Re-Entry

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Pictured is an artist's concept of the X-37 Demonstrator re-entry. After being launched from the cargo bay of a Shuttle as a secondary payload, the X-37 remains on-orbit up to 21 days performing a variety of experiments before re-entering the Earth's atmosphere and landing. These vehicles supported the Agency's goal of dramatically reducing the cost of access to space in attempt to define the future of space transportation. The X-37 program was discontinued in 2003.

  11. Orbit re-entry experiment vehicle development

    NASA Astrophysics Data System (ADS)

    Yamamoto, Masataka; Yamawaki, Kouji; Akimoto, Toshio; Murakami, Atsushi; Inaba, Motoyuki; Kaneko, Yutaka; Shimoda, Takayuki; Ishii, Yasuo; Izumi, Tatsushi; Kawano, Isao

    1992-08-01

    An overview of the Orbital Re-entry Experiment (OREX) vehicle development, including detail design, analyses on the overall system, guidance and control, propulsion, and data acquisition systems is presented. The outline of the experiment vehicle is shown. OREX flight is analyzed and the splash down point variance ellipse is shown. Vehicle body aerodynamic characteristics were analyzed and validated by supersonic wind tunnel and dynamically balanced wind tunnel tests. Analyses on onboard equipment environmental resistance, controllability from on orbit to re-entry phases and navigation and guidance of the space plane were conducted. It was confirmed that there was no problem on the guidance and control system. Review on the propellant volume and analyses on the propulsion system performance, propulsion system heat exchanger performance, and thruster and piping system temperature were conducted and possibility of hard starting of the 150 N hydrazine thruster was noticed. RF (Radio Frequency) link analyses were conducted around Tanegashima, Ogasawara, and the splash down area and prospect of continuously acquiring good link margin for 300 seconds was obtained. Semi unitized structure of truncated cone shape with main body made of aluminum alloy, which has application record for rockets, laid with skin, stringers, and frames was employed for the structure. Data acquisition systems for tracking and operation, including those at Tanegashima, Ogasawara, Christmas, down range ship, and airplane tracking stations were studied.

  12. Worldwide growth market forecast for re-entry drilling

    SciTech Connect

    1996-10-01

    Operators worldwide hail re-entry drilling as the fastest growing development technique in the business. With re-entry technology advancing on a number of fronts, the only question seems to be which re-entry technique is best to get optimum well productivity. Discussions now address how best to proceed: traditional re-entry (RED), coiled tubing drilling (CTD) or short radius (SRD). New technology is definitely fueling a methodology shift in favor of coiled tubing drilling and short radius drilling. Petroleum Engineer International explored the booming re-entry business with operators from the North Sea and North American markets. The paper contains the operators` thoughts on re-entry drilling.

  13. The Secret of Guided Missile Re-Entry,

    DTIC Science & Technology

    1986-06-25

    near vacuum. The success of guided missile re-entry writes a shining page in modern aerospace history! Starting with Meteors The meteor is a re-entry...Only a small portion survives and hits the earth’s surface as a meteorite . A meteor burns during its re-entry; then, what is the destiny of the...warhead of an intercontinental guided missile during its high speed re-entry? Will it be destroyed like the meteor ? This is indeed a big problem in the

  14. Re-Entry Mission Analysis of the Advanced Re-entry Vehicle (ARV)

    NASA Astrophysics Data System (ADS)

    Bonetti, D.; Haya Ramos, R.; Strauch, H.; Bottacini, M.

    2011-08-01

    This paper presents the results of the DEIMOS Space S.L.U. Re-entry Mission Analysis activities obtained in the frame of the Phase A up to PRR milestone of the Advanced Re-entry Vehicle (ARV) ESA project leaded by ASTRIUM. Results presented show how the trajectory and the vehicle design are strictly related and how a feasible and robust solution can be efficiently obtained by considering since the beginning several constraints limiting the design. The process implemented combines the design of key vehicle and trajectory parameters. Once the vehicle design parameters and the conditions at the EIP are fixed, the Mission Analysis is completed by the definition of the optimal trajectory from the deorbiting to the EIP that allow the correct targeting of the EIP conditions but also a safe separation of the different modules and the correct targeting of the desired landing site.

  15. Re-Entry Mission Analysis Of The Advanced Re-Entry Vehicle (ARV)

    NASA Astrophysics Data System (ADS)

    Bonetti, Davide; Haya Ramos, Rodrigo; Strauch, Hans; Bottacini, Massimiliano

    2011-05-01

    This paper presents the results of the DEIMOS Space S.L.U. Re-entry Mission Analysis activities obtained in the frame of the Phase A up to PRR milestone of the Advanced Re-entry Vehicle (ARV) ESA project leaded by ASTRIUM. Results presented show how the trajectory and the vehicle design are strictly related and how a feasible and robust solution can be efficiently obtained by considering since the beginning several constraints limiting the design. The process implemented combines the design of key vehicle and trajectory parameters. Once the vehicle design parameters and the conditions at the EIP are fixed, the Mission Analysis is completed by the definition of the optimal trajectory from the de- orbiting to the EIP that allow the correct targeting of the EIP conditions but also a safe separation of the different modules and the correct targeting of the desired landing site.

  16. Re-Entry: Managing Cross-Cultural Transitions.

    ERIC Educational Resources Information Center

    Adler, Nancy J.

    1981-01-01

    Studied the re-entry process of corporate and governmental employees (N=200) returning to Canada after working overseas. Research found re-entry into the original culture was a more difficult transition than moving to the foreign culture. Home-country managers tended to exhibit xenophobia in assessing the potential and actual effectiveness of…

  17. An Evaluation Guide for College Women's Re-entry Programs.

    ERIC Educational Resources Information Center

    Mezirow, Jack; Rose, Amy D.

    Since 1970, over 300 community colleges have established re-entry programs designed especially for women who are either continuing their education or entering the job market after an extended hiatus. Re-entry programs vary in scope and in the nature of services provided, with some offering specific skills on vocational training, and others…

  18. Re-Entry Predictions for Uncontrolled Satellites: Results and Challenges

    NASA Astrophysics Data System (ADS)

    Pardini, Carmen; Anselmo, Luciano

    2013-09-01

    Currently, approximately 70% of the re-entries of intact orbital objects are uncontrolled, corresponding to about 50% of the returning mass, i.e. ˜100 metric tons per year. On average, there is one spacecraft or rocket body uncontrolled re-entry every week, with an average mass around 2000 kg. Even though a detailed demise analysis is available only occasionally, in many cases the alert casualty expectancy threshold of 1:10,000 is probably violated.Re-entry predictions are affected by various sources of inevitable uncertainty and, in spite of decades of efforts, mean relative errors of 20% often occur. This means that even predictions issued 3 hours before re-entry may be affected by an along-track uncertainty of 40,000 km (corresponding to one orbital path), possibly halved during the last hour. However, specific methods and procedures have been developed to provide understandable and unambiguous information useful for civil protection planning and applications.

  19. ISS Update: ATV-3 ReEntry Breakup Recorder

    NASA Image and Video Library

    ISS Update Commentator Pat Ryan talks with Dr. William Ailor, Principal Investigator for the ReEntry Breakup Recorder (REBR) for The Aerospace Corporation. Ailor talks about capturing data as Europ...

  20. Simulation of the ATV Re-Entry Obsrvations

    NASA Astrophysics Data System (ADS)

    Bastida Virgili, B.; Krag, H.; Lips, T.; De Pasquale, E.

    2010-09-01

    The first ATV was launched on 9th March 2008 and, after a successful mission, the last phase was a controlled destructive re-entry on 29th September 2008, shortly after 13:30 UTC, in which the remains of the ATV and its load fell into the South Pacific Ocean. In order to better understand the re-entry processes, an insitu optical observation campaign was launched to record and analyze the ATV controlled re-entry with several instruments on board of two airplanes and also from the ISS. This observation campaign was successful and triggered several different still-ongoing studies on the extraction and analysis of data to draw conclusions on the adequacy of the re-entry break-up and explosion models used for the safety analysis of the ATV re-entry. This paper addresses the validation process for ESA’s model for re-entry survivability and on-ground risk assessment for explosive re-entry events using the observation data. The underlying rationale is to improve the models for the benefit of planning and execution of future controlled re-entries and in risk calculation in case of uncontrolled ones. The re-entry trajectory of the ATV, the explosive event and the trajectories of the fragments are simulated with the existing ESA tools and the EVOLVE explosion model. Additional software has been developed to simulate airborne sensor field of view(FOV) crossings based on the aircraft trajectories, attitude profile, sensor mounts and FOVs. Sensor performance and object radiation are modeled in order to generate synthetic images for the different sensors in the ISS and the two airplanes. These synthetic images and synthetic videos are compared with the available reentry observations of the ATV. This paper will present the software and techniques to generate synthetic imagery. It will give results of the comparison between the simulated and the real trajectories and fragmentation and explain the subsequent validation process of the ESA re-entry tools and the potential

  1. Satellite Re-entry Modeling and Uncertainty Quantification

    NASA Astrophysics Data System (ADS)

    Horsley, M.

    2012-09-01

    LEO trajectory modeling is a fundamental aerospace capability and has applications in many areas of aerospace, such as maneuver planning, sensor scheduling, re-entry prediction, collision avoidance, risk analysis, and formation flying. Somewhat surprisingly, modeling the trajectory of an object in low Earth orbit is still a challenging task. This is primarily due to the large uncertainty in the upper atmospheric density, about 15-20% (1-sigma) for most thermosphere models. Other contributions come from our inability to precisely model future solar and geomagnetic activities, the potentially unknown shape, material construction and attitude history of the satellite, and intermittent, noisy tracking data. Current methods to predict a satellite's re-entry trajectory typically involve making a single prediction, with the uncertainty dealt with in an ad-hoc manner, usually based on past experience. However, due to the extreme speed of a LEO satellite, even small uncertainties in the re-entry time translate into a very large uncertainty in the location of the re-entry event. Currently, most methods simply update the re-entry estimate on a regular basis. This results in a wide range of estimates that are literally spread over the entire globe. With no understanding of the underlying distribution of potential impact points, the sequence of impact points predicted by the current methodology are largely useless until just a few hours before re-entry. This paper will discuss the development of a set of the High Performance Computing (HPC)-based capabilities to support near real-time quantification of the uncertainty inherent in uncontrolled satellite re-entries. An appropriate management of the uncertainties is essential for a rigorous treatment of the re-entry/LEO trajectory problem. The development of HPC-based tools for re-entry analysis is important as it will allow a rigorous and robust approach to risk assessment by decision makers in an operational setting. Uncertainty

  2. Pesticides re-entry dermal exposure of workers in greenhouses.

    PubMed

    Caffarelli, V; Conte, E; Correnti, A; Gatti, R; Musmeci, F; Morali, G; Spagnoli, G; Tranfo, G; Triolo, L; Vita, M; Zappa, G

    2004-01-01

    This research has the aim to evaluate the risk of pesticide dermal exposure for workers in greenhouses. We considered the following crops: tomato, cucumber and strawberry, largely spread in Bracciano lake district. The pesticides monitored were: tetradifon on strawberry: metalaxyl, azoxystrobin and fenarimol on cucumber; acrinathrin, azoxystrobin and chlorpyrifos ethyl on tomato. The dermal exposure was evaluated by Dislodgeable Foliar Residue (DFR) measurements employing transfer coefficients got from literature. For risk evaluation, we have compared the dermal exposures with Acceptable Operator Exposure Levels (AOEL). The re-entry time were obtained intercepting the dose decay curves with AOEL values. The re-entry times result higher than two days in the cases of chlorpyrifos on tomato (re-entry time: 3 days), azoxystrobin on tomato (4 days), and tetradifon on strawberry (8 days). The need of measuring specific transfer coefficients is pointed out.

  3. Missile Aerodynamics for Ascent and Re-entry

    NASA Technical Reports Server (NTRS)

    Watts, Gaines L.; McCarter, James W.

    2012-01-01

    Aerodynamic force and moment equations are developed for 6-DOF missile simulations of both the ascent phase of flight and a tumbling re-entry. The missile coordinate frame (M frame) and a frame parallel to the M frame were used for formulating the aerodynamic equations. The missile configuration chosen as an example is a cylinder with fixed fins and a nose cone. The equations include both the static aerodynamic coefficients and the aerodynamic damping derivatives. The inclusion of aerodynamic damping is essential for simulating a tumbling re-entry. Appended information provides insight into aerodynamic damping.

  4. Airborne re-entry observation experiment SLIT: UV spectroscopy during STARDUST and ATV1 re-entry

    NASA Astrophysics Data System (ADS)

    Löhle, Stefan; Wernitz, Ricarda; Herdrich, Georg; Fertig, Markus; Röser, Hans-Peter; Ritter, Heiko

    2011-09-01

    Emission spectra during re-entry have been measured in 2006 for the STARDUST capsule and in 2008 for the ATV1 "Jules Verne" re-entry. This paper summarizes the approach to design the airborne UV spectroscopic setup and its modifications with respect to the missions. For the STARDUST mission, results of data analysis of data presented in 2008 are given while for the ATV1 observation first spectra of the main disruption are exemplary presented. The surface radiation during the STARDUST re-entry is used to estimate convective and radiative heat flux using different analytical models. A first look at the spectroscopic footprint of ATV1 shows that during the first explosive event, a severe break-up of the main ATV1 structure occurs. However, a correlation with an explosion of fuel could not be observed.

  5. Calibration of Radar Based Re-Entry Predictions

    NASA Astrophysics Data System (ADS)

    Lemmens, S.; Bastida Virgili, B.; Flohrer, T.; Gini, F.; Krag, H.; Steiger, C.

    2015-03-01

    The availability of GPS observations via the telemetry during GOCE’s (Gravity Field and Steady-State Ocean Circulation Explorer) entire re-entry campaign enabled the generation of high quality orbit products which can be used as input to re-entry predictions. These high precision orbits can be used as reference to assess the quality of orbits generated from other sources. Here we verify the accuracy of orbits based on radar tracking data, obtained by dedicated observations with the Tracking & Imaging Radar system from the Fraunhofer High Frequency Physics and Radar Techniques institute, with respect to the a post-processed GPS based reference orbit. This leads to time-depended quantification of the orbit determination uncertainties on the re-entry predictions. Furthermore, the ballistic coefficient determined by the orbit determination and its time dependent evolution can be used to a priori estimate the attitude behaviour of GOCE, which can be compared to the telemetry. The attitude behaviour can be analysed by the use of inverse synthetic aperture radar (ISAR) images, also obtained by dedicated observation by TIRA. The effect of adding this knowledge on the attitude evolution to the re-entry predictions is evaluated.

  6. Re-entry Women and Graduate School. Field Evaluation Draft.

    ERIC Educational Resources Information Center

    Fisher-Thompson, Jeanne

    Problems and barriers women often face when re-entering the educational system at the graduate level are identified, and ways in which institutions can be more responsive to the needs of re-entry students are suggested. A wide range of possible actions is included so that institutions can pursue those most appropriate to their individual…

  7. Sacramento City College Re-Entry Services Comprehensive Plan.

    ERIC Educational Resources Information Center

    White, Maureen E.; Smith, William A.

    Sacramento City College (SCC) established its Re-Entry Services program to provide information, referral and support services to students returning to the academic environment after an absence. Since the inception of the program in 1977, the college community has changed considerably. Among these changes are an aging student population, increased…

  8. Controlled Re-Entry of the H-IIB Launch Vehicle Upper Stage with the Use of the Re-Entry Safety System

    NASA Astrophysics Data System (ADS)

    Ida, K.; Mori, S.; Sakamoto, K.; Ikeda, S.; Sato, T.; Kawabata, H.

    2012-01-01

    On January 22, 2011, during flight No. 2 of the H-IIB launch vehicle, the Japan Aerospace Exploration Agency (JAXA) succeeded in performing a controlled re-entry experiment for the upper stage. This is the first time this has been done for the upper stage of a Japanese launch vehicle. For flight No. 1, the upper stage performed a random re- entry. With a view to avoiding debris generation and debris-related impact accidents, JAXA resolved to develop a more refined re-entry process. Consequently, the "Re-entry Safety System" was developed in order to achieve controlled re-entry with certainty. After one orbit, while executing controlled re-entry, the Re-entry Safety System monitored the upper stage's function and orbit. Subsequently, a command disengaging the lockout of the deorbit manoeuvre was issued from ground and re-entry commenced. The details of the Re-entry Safety System, which facilitated the controlled re-entry, are described herein.

  9. Inflatable Re-entry Vehicle Experiment (IRVE-4) Overview

    NASA Technical Reports Server (NTRS)

    Litton, Daniel K.; Bose, David M.; Cheatwood, F. McNeil; Hughes, Stephen; Wright, Henry S.; Lindell, Michael C.; Derry, Stephen D.; Olds, Aaron

    2011-01-01

    The suite of Inflatable Re-Entry Vehicle Experiments (IRVE) is designed to further our knowledge and understanding of Hypersonic Inflatable Aerodynamic Decelerators (HIADs). Before infusion into a future mission, three challenges need to be addressed: surviving the heat pulse during re-entry, demonstrating system performance at relevant scales, and demonstrating controllability in the atmosphere. IRVE-4 will contribute to a better understanding of controllability by characterizing how a HIAD responds to a set of controlled inputs. The ability to control a HIAD is vital for missions that are g-limited, require precision targeting and guidance for aerocapture or entry, descent, and landing. The IRVE-4 flight test will focus on taking a first look into controlling a HIAD. This paper will give an overview of the IRVE-4 mission including the control response portion of the flight test sequence, and will provide a review of the mission s development.

  10. Control Surface Seals Investigated for Re- Entry Vehicles

    NASA Technical Reports Server (NTRS)

    Dunlap, Patrick H.; Steinetz, Bruce M.

    2003-01-01

    Re-entry vehicles generally use control surfaces (e.g., rudders, body flaps, and elevons) to steer or guide them as they pass into and through the Earth s atmosphere. High temperature seals are required around control surfaces both along hinge lines and in areas where control surface edges seal against the vehicle body to limit hot gas ingestion and the transfer of heat to underlying low-temperature structures. Working with the NASA Johnson Space Center, the Seals Team at the NASA Glenn Research Center completed a series of tests on the baseline seal design for the rudder/fin control surface interfaces of the X-38 vehicle. This seal application was chosen as a case study to evaluate a currently available control surface seal design for applications in future re-entry vehicles. The structures of the rudder/fin assembly and its associated seals are shown in the following illustration.

  11. Workforce re-entry for Japanese unemployed dental hygienists.

    PubMed

    Usui, Y; Miura, H

    2015-02-01

    The aim of this study was to define the profile of unemployed dental hygienists who could be enticed to re-enter the workforce and the factors that could facilitate their re-entry into the dental field in Japan. The questionnaire was mailed with a postage-paid return envelope to a sample of 3095 licensed dental hygienists. A 50.4% response rate (S = 1477) was observed. The rate of working dental hygienists was 60.3% (n = 891), and of unemployed dental hygienists was 39.7% (n = 586). Of the latter, 31.9% (n = 187) stated intentions of returning to the workplace. The unemployed dental hygienists seeking employment were more often married and had more children, compared with working dental hygienists currently. This group also had significantly fewer total service years. Moreover, only 11.96% of them belonged to the Japan Dental Hygienists' Association, and 41.3% of those attended training workshops. According to their response, they perceived their top three major barriers to re-entry as 'lack sufficient dental hygiene skill', 'child rearing' and 'poor working atmosphere'. 'Flexibility in the work schedule' and 'location' were the most important factors for re-entry from their perspective. There were not many dental hygienists hoping to return to the dental field. The findings suggested that strategies to encourage non-practicing dental hygienists to re-entry should be emphasized in the areas of a flexible working atmosphere, easy access to information on how to return to practice and guidance on how to maintain professionalism during inactivity. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. FLPP IXV Re-Entry Vehicle, Aerodynamic Characterisation

    NASA Astrophysics Data System (ADS)

    Belmont, J.-P.; Cantinaud, O.; Tribot, J.-P.; Walloschek, T.

    2009-01-01

    The European Space Agency ESA, has engaged in 2004, the IXV project (Intermediate eXperimental Vehicle) which is part of the FLPP (Future Launcher Preparatory Programme) aiming at answering to critical technological issues, while supporting the future generation launchers and improving in general European capabilities in the strategic field of atmospheric re-entry for space transportation, exploration, and scientific applications. The IXV key mission and system objectives are the design, development, manufacturing, assembling and on- ground to in-flight verification of an autonomous European lifting and aerodynamically controlled re- entry system, integrating the critical re-entry technologies at the system level. The current IXV vehicle is a slender body type exhibiting rounded shape and thick body. Since the beginning of the IXV project, an aerodynamic data base (AEDB) has been built up and continuously updated integrating the additional information mainly provided by means of CFD. The AEDB includes nominal aerodynamic data, a new set of free molecular aerodynamic coefficients as well as aerodynamic uncertainties. Through the phase B2/C1, complementary computations were performed (CFSE, EPFL, ASTRIUM, TAS, DAA) as well as wind tunnel tests such as ONERA S4ma, DLR H2K, DNW/NLR SST, FOI T1500. All data were analyzed and compared enabling the consolidation of the nominal aerodynamic and aerodynamic uncertainties as well. The paper presents the logic of work based on the system engineering plan with emphasis on the different prediction tools used aiming the final aerodynamic characterization of the IXV configuration.

  13. High performance modeling of atmospheric re-entry vehicles

    NASA Astrophysics Data System (ADS)

    Martin, Alexandre; Scalabrin, Leonardo C.; Boyd, Iain D.

    2012-02-01

    Re-entry vehicles designed for space exploration are usually equipped with thermal protection systems made of ablative material. In order to properly model and predict the aerothermal environment of the vehicle, it is imperative to account for the gases produced by ablation processes. In the case of charring ablators, where an inner resin is pyrolyzed at a relatively low temperature, the composition of the gas expelled into the boundary layer is complex and may lead to thermal chemical reactions that cannot be captured with simple flow chemistry models. In order to obtain better predictions, an appropriate gas flow chemistry model needs to be included in the CFD calculations. Using a recently developed chemistry model for ablating carbon-phenolic-in-air species, a CFD calculation of the Stardust re-entry at 71 km is presented. The code used for that purpose has been designed to take advantage of the nature of the problem and therefore remains very efficient when a high number of chemical species are involved. The CFD result demonstrates the need for such chemistry model when modeling the flow field around an ablative material. Modeling of the nonequilibrium radiation spectra is also presented, and compared to the experimental data obtained during Stardust re-entry by the Echelle instrument. The predicted emission from the CN lines compares quite well with the experimental results, demonstrating the validity of the current approach.

  14. Coronas-F Orbit Monitoring and Re-Entry Prediction

    NASA Technical Reports Server (NTRS)

    Ivanov, N. M.; Kolyuka, Yu. F.; Afanasieva, T. I.; Gridchina, T. A.

    2007-01-01

    Russian scientific satellite CORONAS-F was launched on July, 31, 2001. The object was inserted in near-circular orbit with the inclination 82.5deg and a mean altitude approx. 520 km. Due to the upper atmosphere drag CORONAS-F was permanently descended and as a result on December, 6, 2005 it has finished the earth-orbital flight, having lifetime in space approx. 4.5 years. The satellite structural features and its flight attitude control led to the significant variations of its ballistic coefficient during the flight. It was a cause of some specific difficulties in the fulfillment of the ballistic and navigation support of this space vehicle flight. Besides the main mission objective CORONAS-F also has been selected by the Inter-Agency Space Debris Coordination Committee (IADC) as a target object for the next regular international re-entry test campaign on a program of surveillance and re-entry prediction for the hazard space objects within their de-orbiting phases. Spacecraft (S/C) CORONAS-F kept its working state right up to the end of the flight - down to the atmosphere entry. This fact enabled to realization of the additional research experiments, concerning with an estimation of the atmospheric density within the low earth orbits (LEO) of the artificial satellites, and made possible to continue track the S/C during final phase of its flight by means of Russian regular command & tracking system, used for it control. Thus there appeared a unique possibility of using for tracking S/C at its de-orbiting phase not only passive radar facilities, belonging to the space surveillance systems and traditionally used for support of the IADC re-entry test campaigns, but also more precise active trajectory radio-tracking facilities from the ground control complex (GCC) applied for this object. Under the corresponding decision of the Russian side such capability of additional high-precise tracking control of the CORONAS-F flight in this period of time has been implemented

  15. Flap effectiveness appraisal for winged re-entry vehicles

    NASA Astrophysics Data System (ADS)

    de Rosa, Donato; Pezzella, Giuseppe; Donelli, Raffaele S.; Viviani, Antonio

    2016-05-01

    The interactions between shock waves and boundary layer are commonplace in hypersonic aerodynamics. They represent a very challenging design issue for hypersonic vehicle. A typical example of shock wave boundary layer interaction is the flowfield past aerodynamic surfaces during control. As a consequence, such flow interaction phenomena influence both vehicle aerodynamics and aerothermodynamics. In this framework, the present research effort describes the numerical activity performed to simulate the flowfield past a deflected flap in hypersonic flowfield conditions for a winged re-entry vehicle.

  16. New tool allows selective multi-lateral re-entry

    SciTech Connect

    1997-05-01

    This article overviews the world`s first application of a downhole tool installed after the drilling and completion of a lateral borehole from a larger backbone casing, to allow future access to the lateral using through-tubing, coiled tubing operations. The system described is based on the Multi Lateral Selective Re-Entry System, or MLR (trademark), supplied by Pressure Control Engineering Ltd. (PCE) of Poole, Dorset, England. Primary equipment used in creating the lateral completion and its tieback to the backbone liner was supplied by Sperry Sun.

  17. Atomic and molecular data for spacecraft re-entry plasmas

    NASA Astrophysics Data System (ADS)

    Celiberto, R.; Armenise, I.; Cacciatore, M.; Capitelli, M.; Esposito, F.; Gamallo, P.; Janev, R. K.; Laganà, A.; Laporta, V.; Laricchiuta, A.; Lombardi, A.; Rutigliano, M.; Sayós, R.; Tennyson, J.; Wadehra, J. M.

    2016-06-01

    The modeling of atmospheric gas, interacting with the space vehicles in re-entry conditions in planetary exploration missions, requires a large set of scattering data for all those elementary processes occurring in the system. A fundamental aspect of re-entry problems is represented by the strong non-equilibrium conditions met in the atmospheric plasma close to the surface of the thermal shield, where numerous interconnected relaxation processes determine the evolution of the gaseous system towards equilibrium conditions. A central role is played by the vibrational exchanges of energy, so that collisional processes involving vibrationally excited molecules assume a particular importance. In the present paper, theoretical calculations of complete sets of vibrationally state-resolved cross sections and rate coefficients are reviewed, focusing on the relevant classes of collisional processes: resonant and non-resonant electron-impact excitation of molecules, atom-diatom and molecule-molecule collisions as well as gas-surface interaction. In particular, collisional processes involving atomic and molecular species, relevant to Earth (N2, O2, NO), Mars (CO2, CO, N2) and Jupiter (H2, He) atmospheres are considered.

  18. Orbiter Gap Filler Bending Model for Re-entry

    NASA Technical Reports Server (NTRS)

    Campbell, Charles H.

    2007-01-01

    Pressure loads on a protruding gap filler during an Orbiter reentry are investigated to evaluate the likelihood of extraction due to pressure loads, and to ascertain how much bending will be induced by re-entry pressure loads. Oblique shock wave theory is utilized to develop a representation of the pressure loads induced on a gap filler for the ISSHVFW trajectory, representative of a heavy weight ISS return. A free body diagram is utilized to react the forces induced by the pressure forces. Preliminary results developed using these methods demonstrate that pressure loads, alone, are not likely causes of gap filler extraction during reentry. Assessment of the amount a gap filler will bend over is presented. Implications of gap filler bending during re-entry include possible mitigation of early boundary layer transition concerns, uncertainty in ground based measurement of protruding gap fillers from historical Orbiter flight history, and uncertainty in the use of Orbiter gap fillers for boundary layer prediction calibration. Authors will be added to the author list as appropriate.

  19. Investigations of Control Surface Seals for Re-entry Vehicles

    NASA Technical Reports Server (NTRS)

    Dunlap, Patrick H., Jr.; Steinetz, Bruce M.; Curry, Donald M.; DeMange, Jeffrey J.; Rivers, H. Kevin; Hsu, Su-Yuen

    2002-01-01

    Re-entry vehicles generally require control surfaces (e.g., rudders, body flaps) to steer them during flight. Control surface seals are installed along hinge lines and where control surface edges move close to the vehicle body. These seals must operate at high temperatures and limit heat transfer to underlying structures to prevent them from overheating and causing possible loss of vehicle structural integrity. This paper presents results for thermal analyses and mechanical testing conducted on the baseline rudder/fin seal design for the X-38 re-entry vehicle. Exposure of the seals in a compressed state at the predicted peak seal temperature of 1900 F resulted in loss of seal resiliency. The vertical Inconel rudder/fin rub surface was re-designed to account for this loss of resiliency. Room temperature compression tests revealed that seal unit loads and contact pressures were below limits set to protect Shuttle thermal tiles on the horizontal sealing surface. The seals survived an ambient temperature 1000 cycle scrub test over sanded Shuttle tiles and were able to disengage and re-engage the tile edges during testing. Arc jet tests confirmed the need for seals in the rudder/fin gap location because a single seal caused a large temperature drop (delta T = 1710 F) in the gap.

  20. MHD of Aircraft Re-entry: Limits and Perspectives

    SciTech Connect

    Seller, G.; Capitelli, M.; Longo, S.; Armenise, I.; Bruno, D.

    2005-05-16

    In the present work, starting from classical MHD scheme, based on Maxwell equations, Euler fluid dynamic equations and generalised Ohm law, a critical study of fluid dynamics, electromagnetism, chemical and physical behaviour of plasma is carried out, and then a aircraft re-entry MHD numerical scheme is implemented. This scheme is used for MHD calculations in different conditions, in the range of low magnetic force and intermediate electrical conductivity. Initial imposed magnetic fields are uniform, but also some cases with coil generated magnetic fields are considered. Calculations of magnetic field and induced currents are extended also inside the blunt body. Results show interesting physical and electromagnetic effects. Comparison with other methods shows possible development in keeping into account other physical and chemical effects.

  1. MHD of Aircraft Re-entry: Limits and Perspectives

    NASA Astrophysics Data System (ADS)

    Seller, G.; Capitelli, M.; Longo, S.; Armenise, I.; Bruno, D.

    2005-05-01

    In the present work, starting from classical MHD scheme, based on Maxwell equations, Euler fluid dynamic equations and generalised Ohm law, a critical study of fluid dynamics, electromagnetism, chemical and physical behaviour of plasma is carried out, and then a aircraft re-entry MHD numerical scheme is implemented. This scheme is used for MHD calculations in different conditions, in the range of low magnetic force and intermediate electrical conductivity. Initial imposed magnetic fields are uniform, but also some cases with coil generated magnetic fields are considered. Calculations of magnetic field and induced currents are extended also inside the blunt body. Results show interesting physical and electromagnetic effects. Comparison with other methods shows possible development in keeping into account other physical and chemical effects.

  2. Re-Entry Guidance Using an Energy-State Equation

    NASA Astrophysics Data System (ADS)

    Abe, Akio; Shimada, Yuzo; Uchiyama, Kenji

    This paper presents a new guidance and control system for a re-entry vehicle. In the conventional drag acceleration control system employed for the present space shuttles, the velocity is an unobservable state variable and the associated pole tends to be unstable. Therefore, in this study, a condition which allows all the states to be observable is introduced using a state-space linearization method. It is also shown that energy and its rate are appropriate for the state variables. A guidance law is analytically derived on the basis of the obtained state equation with respect to the energy by solving a two-point boundary-value problem. Furthermore, a tracking control system is designed to make the position, velocity, and flight path angle of the vehicle track the reference states generated in the guidance system. Finally, numerical simulation is performed to verify the validity of the obtained plant expression, and the effectiveness of the proposed guidance and control system.

  3. FLPP IXV Re-Entry Vehicle, Hypersonic Aerodynamics Characterisation

    NASA Astrophysics Data System (ADS)

    Tran, Ph.; Dormieux, M.; Fontaine, J.; Gülhan, A.; Tribot, J.-P.; Binetti, P.; Walloschek, T.

    2009-01-01

    The general objective of the IXV project (Intermediate eXperimental Vehicle), led by NGL Prime in the framework of the ESA FLPP programme (Future Launchers Preparatory Programme), is to improve European capabilities in the strategic field of atmospheric re-entry for space transportation, exploration, and scientific applications. One of the key objectives and challenges of the IXV project is the vehicle re-entry guidance and control demonstration which requires an accurate determination of the aerodynamic characteristics. This paper deals with all the aerodynamic characterization in the hypersonic flow regime. Wind tunnel tests (WTT) and CFD matrices have been defined in order to provide good coverage of the foreseen flight domain, account for uncertainties, and exploit the synergy between experimental and computational activity. WTT have been performed in DLR-H2K (M=6 and 8.7) and ONERA-S4Ma (M=10) facilities, gathering forces and moment data, as well as pressure in key areas. Consistency of the two campaigns results will be addressed. These results have highlighted some flow peculiarities in the deflected flap region. Comparisons with CFD show good agreement with ground experimental results. For flight conditions, real gas and viscous effects play a significant role in the trim conditions that only CFD can currently address; this identification was supported by different partners involved in the project (CFS engineering, DLR, CIRA, and the University of Rome) providing a valuable description of key flow phenomena affecting aerodynamic characteristics. Moreover, at high altitude, limited DSMC computations have been performed for bridging function correction.

  4. Re-Entry of Women to the Labour Market After an Interruption in Employment.

    ERIC Educational Resources Information Center

    Seear, B. N.

    The problems involved in the re-entry of women into employment were studied, and the extent to which there exists a demand for employment for re-entry women was examined. A growing number of women are seeking re-entry in a wide range of income levels. The demand for part-time work appears to exceed supply. Official machinery for assisting re-entry…

  5. Effect of fibre rotation on the initiation of re-entry in cardiac tissue.

    PubMed

    Vigmond, E J; Leon, L J

    2001-07-01

    Transmural rotation of cardiac fibres can have a big influence on the initiation of re-entry in the heart. However, owing to computational demands, this has not been fully explored in a three-dimensional model of cardiac tissue that has a microscopic description of membrane currents, such as the Luo-Rudy model. Using a previously described model that is computationally fast, re-entry in three-dimensional blocks of cardiac tissue is induced by a cross-shock protocol, and the activity is examined. In the study, the effect of the transmural fibre rotation is ascertained by examining differences between a tissue block with no rotation and ones with 1, 2 and 3 degrees of rotation per fibre layer. The direction of the re-entry is significant in establishing whether or not re-entry can be induced, with clockwise re-entry being easier to initiate. Owing to the rotating anisotropy that results in preferential propagation along the fibre axis, the timing of the second stimulus in the cross-shock protocol has to be changed for different rates of fibre rotation. The fibre rotation either increases or decreases the window of opportunity for re-entry, depending on whether the activation front is perpendicular or parallel to the fibre direction. By varying the transmural extent of the S2, it is found that a deeper stimulus has to be applied to the blocks with fibre rotation to create re-entry. Increasing the transmural resistance also tends to reduce the extent of the S2 required to induce re-entry. Results suggest that increasing fibre rotation reduces the susceptibility of the tissue to re-entry, but that more complex spatiotemporal patterns are possible, e.g. stable figure-of-eight re-entries and transient rotors. Three mechanisms of re-entry annihilation are identified: front catchup, filling of the excitable gap and core wander.

  6. Hayabusa Re-Entry: Trajectory Analysis and Observation Mission Design

    NASA Technical Reports Server (NTRS)

    Cassell, Alan M.; Winter, Michael W.; Allen, Gary A.; Grinstead, Jay H.; Antimisiaris, Manny E.; Albers, James; Jenniskens, Peter

    2011-01-01

    On June 13th, 2010, the Hayabusa sample return capsule successfully re-entered Earth s atmosphere over the Woomera Prohibited Area in southern Australia in its quest to return fragments from the asteroid 1998 SF36 Itokawa . The sample return capsule entered at a super-orbital velocity of 12.04 km/sec (inertial), making it the second fastest human-made object to traverse the atmosphere. The NASA DC-8 airborne observatory was utilized as an instrument platform to record the luminous portion of the sample return capsule re-entry (60 sec) with a variety of on-board spectroscopic imaging instruments. The predicted sample return capsule s entry state information at 200 km altitude was propagated through the atmosphere to generate aerothermodynamic and trajectory data used for initial observation flight path design and planning. The DC- 8 flight path was designed by considering safety, optimal sample return capsule viewing geometry and aircraft capabilities in concert with key aerothermodynamic events along the predicted trajectory. Subsequent entry state vector updates provided by the Deep Space Network team at NASA s Jet Propulsion Laboratory were analyzed after the planned trajectory correction maneuvers to further refine the DC-8 observation flight path. Primary and alternate observation flight paths were generated during the mission planning phase which required coordination with Australian authorities for pre-mission approval. The final observation flight path was chosen based upon trade-offs between optimal viewing requirements, ground based observer locations (to facilitate post-flight trajectory reconstruction), predicted weather in the Woomera Prohibited Area and constraints imposed by flight path filing deadlines. To facilitate sample return capsule tracking by the instrument operators, a series of two racetrack flight path patterns were performed prior to the observation leg so the instruments could be pointed towards the region in the star background where

  7. GPK-2 re-entry and deepening -- a technical report

    SciTech Connect

    Baumgartner, J.; Gerard, A.; Barla, R.; Socomine, S.A.

    1999-01-01

    Between mid February to end of May 1999 (in 104 days) the well GPK2 at the Soultz HDR site was successfully re-entered and deepened from 3876 m to a final depth of 5084 m and fully completed. Re-entry included the pulling of the existing 321 1 m long internal 9 5/8-inch by 7-inch casing string, fishing of a submersible pump and some 150 m of 2 3/8-inch tubing, sealing of a major loss zone and opening of a 6 1/4-inch well section in granite (3211-3876 m) to 8 1/2-inch hole size. The well was extended to 5048 m in 8 1/2'' hole size and again completed with a floating 9 5/8-inch by 7-inch casing string. The casing shoe is at 4431 m. A bottom hole core was taken in the depth range 5048-5051 m. The core recovery was app. 40%. A pilot hole in 6 1/4-inch was drilled from 5051-5084 m for in situ stress measurements using the hydraulic fracturing technique. The re-entry and deepening of the well GPK2 was accompanied by several technical developments. New casing packer elements based on inflatable metal shells were developed in a close cooperation between SOCOMINE and MeSy GmbH (patent pending). These packer elements were successfully integrated into the completion of the well. The full weight of the casing string is supported by these elements which are filled with and imbedded in cement. High temperature cementing strategies (up to 170-190 C) for the complex saline fluids encountered in Soultz (High Magnesium Resistant Cements) were developed in a cooperation between Schlumberger Dowell (Vechta), SOCOMINE, SII of Houston, Ruhr-University Bochum, BGR Hannover and IFP Paris. The development of several high temperature logging tools (200 C range, 6-arm caliper, PTF probe) was initiated with CSMA (Cornwall) during the preparation of the deepening of GPK2. Initial scientific investigations included borehole logging (NGS, CLIPER, ARI, UBI, TEMPERATURE), geological investigations (cuttings, core) and seismic monitoring while drilling. During the first temperature log performed

  8. Precise Orbit Determination of the GOCE Re-Entry Phase

    NASA Astrophysics Data System (ADS)

    Gini, Francesco; Otten, Michiel; Springer, Tim; Enderle, Werner; Lemmens, Stijn; Flohrer, Tim

    2015-03-01

    During the last days of the GOCE mission, after the GOCE spacecraft ran out of fuel, it slowly decayed before finally re-entering the atmosphere on the 11th November 2013. As an integrated part of the AOCS, GOCE carried a GPS receiver that was in operations during the re-entry phase. This feature provided a unique opportunity for Precise Orbit Determination (POD) analysis. As part of the activities carried out by the Navigation Support Office (HSO-GN) at ESOC, precise ephemerides of the GOCE satellite have been reconstructed for the entire re-entry phase based on the available GPS observations of the onboard LAGRANGE receiver. All the data available from the moment the thruster was switched off on the 21st of October 2013 to the last available telemetry downlink on the 10th November 2013 have been processed, for a total of 21 daily arcs. For this period a dedicated processing sequence has been defined and implemented within the ESA/ESOC NAvigation Package for Earth Observation Satellites (NAPEOS) software. The computed results show a post-fit RMS of the GPS undifferenced carrier phase residuals (ionospheric-free linear combination) between 6 and 14 mm for the first 16 days which then progressively increases up to about 80 mm for the last available days. An orbit comparison with the Precise Science Orbits (PSO) generated at the Astronomical Institute of the University of Bern (AIUB, Bern, Switzerland) shows an average difference around 9 cm for the first 8 daily arcs and progressively increasing up to 17 cm for the following days. During this reentry phase (21st of October - 10th November 2013) a substantial drop in the GOCE altitude is observed, starting from about 230 km to 130 km where the last GPS measurements were taken. During this orbital decay an increment of a factor of 100 in the aerodynamic acceleration profile is observed. In order to limit the mis-modelling of the non-gravitational forces (radiation pressure and aerodynamic effects) the newly developed

  9. Exploring Career Decision-Making Experiences of Mexican American Re-Entry Community College Women

    ERIC Educational Resources Information Center

    Dominguez, Cecilia Sophia

    2010-01-01

    The purpose of this phenomenological investigation was to increase understanding of the career perspectives of 12 Mexican American, re-entry women who were attending a community college. The questions guiding this investigation were: (a) How do Mexican American re-entry college women describe their career decision-making experiences, (b) What do…

  10. Re-Entry, Recruitment, and Retention: A Community Relations Model for Sacramento City College.

    ERIC Educational Resources Information Center

    White, Maureen E.

    Enrollment statistics and projections confirm the importance of focusing community college student recruitment and retention efforts on re-entry students. Re-entry students are a distinct and growing population whose educational requirements often differ from those of younger, traditional students. The literature on adult learners indicates that:…

  11. Spacecraft Re-Entry Impact Point Targeting Using Aerodynamic Drag

    NASA Technical Reports Server (NTRS)

    Omar, Sanny R.; Bevilacqua, Riccardo

    2017-01-01

    The ability to re-enter the atmosphere at a desired location is important for spacecraft containing components that may survive re-entry. While impact point targeting has traditionally been initiated through impulsive burns with chemical thrusters on large vehicles such as the Space Shuttle, and the Soyuz and Apollo capsules, many small spacecraft do not host thrusters and require an alternative means of impact point targeting to ensure that falling debris do not cause harm to persons or property. This paper discusses the use of solely aerodynamic drag force to perform this targeting. It is shown that by deploying and retracting a drag device to vary the ballistic coefficient of the spacecraft, any desired longitude and latitude on the ground can be targeted provided that the maneuvering begins early enough and the latitude is less than the inclination of the orbit. An analytical solution based on perturbations from a numerically propagated trajectory is developed to map the initial state and ballistic coefficient profile of a spacecraft to its impact point. This allows the ballistic coefficient profile necessary to reach a given target point to be rapidly calculated, making it feasible to generate the guidance for the decay trajectory onboard the spacecraft. The ability to target an impact point using aerodynamic drag will enhance the capabilities of small spacecraft and will enable larger space vehicles containing thrusters to save fuel by more effectively leveraging the available aerodynamic drag.

  12. Re-entry aerodynamics derived from space debris trajectory analysis

    NASA Astrophysics Data System (ADS)

    Crowther, R.

    1992-05-01

    This paper considers the technique of orbital analysis as a means of determining the ill-defined gas-surface interaction between spacecraft and atmospheric molecules in low earth orbit. The interaction is a major uncertainty in trajectory predictions for a body moving within an atmosphere. The rate of change of the orbital period of a debris object, the uncontrolled Salyut 7/Kosmos 1686 space station, is analyzed in order to determine the free molecular drag coefficient. The results are compared with theoretical values for the drag coefficient calculated using a complex representation of the vehicle configuration and motion and applying the Monte Carlo Test Particle method. Results suggest a nature of re-emission very close to the classical diffuse, totally accommodated case was occurring at the surface of the debris object as it approached re-entry. However, the determined drag coefficient and therefore the derived interaction are found to be very sensitive to the neutral density and therefore the atmospheric model used in the analysis.

  13. Design Criteria for Low Risk Re-Entry Vehicles

    NASA Astrophysics Data System (ADS)

    Monti, R.; Pezzella, G.

    2005-02-01

    The paper shows how a sharp vehicle with low wing loading, is able to follow re-entry trajectories with low thermal risks by using Ultra High Temperature Ceramics (UHTC) to thermally protect the vehicle front edges. These reusable materials can withstand the global radiative equilibrium temperatures that are experienced during reentry characterized by a longer and a more gradual conversion of the kinetic and potential energy of the vehicle into thermal energy. A number of aerothermodynamic problems are addressed to assess the feasibility of the vehicle design and of the thermal protection of the payload. In particular, the boundary layer thermal protection concept is illustrated to show how a UHTC massive tip edges (fuselage and wings) are able to protect also the remaining vehicle structure made of conventional material, promoting a revolutionary approach to the Thermal Protection System (TPS) configuration for hypersonic vehicle flying at small angle of attack. CFD results and engineering formulations are adopted for the computation of the aerodynamic coefficients and heat fluxes. The analysis identifies the design criteria for a conventional looking vehicle for a crew return from LEO (e.g. from the International Space Station).

  14. DEBRISK, a Tool for Re-Entry Risk Analysis

    NASA Astrophysics Data System (ADS)

    Omaly, P.; Spel, M.

    2012-01-01

    An act of French parliament, adopted in 2008, imposes satellite constructors to evaluate the end-of-life operations in order to assure the risk mitigation of their satellites. One important element in this evaluation is the estimation of the mass and impact energy of the satellite debris after atmospheric re-entry. For this purpose, CNES has developed the tool DEBRISK which allows the operator to simulate the re-entry phase and to study the demise altitudes or impact energy of the individual fragments of the original satellite. DEBRISK is based on the so called object based approach. Using this approach, a breakup altitude is assumed where the satellite disintegrates due to the pressure loads. This altitude is typically around 78 km. After breakup, the satellite structure is modelled by a parent-child approach, where each child has its birth criterion. In the simplest approach the child is born after demise of the parent object. This could be the case of an object A containing an object B which is in the interior of object A and thus not exposed to the atmosphere. Each object is defined by: - its shape, attitude and dimensions, - the material along with their physical properties - the state and velocity vectors. The shape, attitude and dimensions define the aerodynamic drag of the object which is input to the 3DOF trajectory modelling. The aerodynamic mass used in the equation of motion is defined as the sum of the object's own mass and the mass of the object's offspring. A new born object inherits the state vector of the parent object. The shape, attitude and dimensions also define the heating rates experienced by the object. The heating rate is integrated in time up to the point where the melting temperature is reached. The mass of melted material is computed from the excess heat and the material properties. After each step the amount of ablated material is determined using the lumped mass approach and is peeled off from the object, updating mass and shape of the

  15. Passivity analysis for a winged re-entry vehicle

    NASA Astrophysics Data System (ADS)

    Mooij, E.

    2014-12-01

    Application of simple adaptive control (SAC) theory to the design of guidance and control systems for winged re-entry vehicles has been proven successful. To apply SAC to these non-linear and non-stationary systems, it needs to be Almost Strictly Passive (ASP), which is an extension of the Almost Strictly Positive Real (ASPR) condition for linear, time-invariant systems. To fulfill the ASP condition, the controlled, non-linear system has to be minimum-phase (i.e., the zero dynamics is stable), and there is a specific condition for the product of output and input matrix. Earlier studies indicate that even the linearised system is not ASPR. The two problems at hand are: 1) the system is non-minimum phase when flying with zero bank angle, and 2) whenever there is hybrid control, e.g., yaw control is established by combined reaction and aerodynamic control for the major part of flight, the second ASPR condition cannot be met. In this paper we look at both issues, the former related to the guidance system and the latter to the attitude-control system. It is concluded that whenever the nominal bank angle is zero, the passivity conditions can never be met, and guidance should be based on nominal commands and a redefinition of those whenever the error becomes too large. For the remaining part of the trajectory, the passivity conditions are marginally met, but it is proposed to add feedforward compensators to alleviate these conditions. The issue of hybrid control is avoided by redefining the controls with total control moments and adding a so-called control allocator. Deriving the passivity conditions for rotational motion, and evaluating these conditions along the trajectory shows that the (non-linear) winged entry vehicle is ASP. The sufficient conditions to apply SAC for attitude control are thus met.

  16. Passivity analysis for a winged re-entry vehicle

    SciTech Connect

    Mooij, E.

    2014-12-10

    Application of simple adaptive control (SAC) theory to the design of guidance and control systems for winged re-entry vehicles has been proven successful. To apply SAC to these non-linear and non-stationary systems, it needs to be Almost Strictly Passive (ASP), which is an extension of the Almost Strictly Positive Real (ASPR) condition for linear, time-invariant systems. To fulfill the ASP condition, the controlled, non-linear system has to be minimum-phase (i.e., the zero dynamics is stable), and there is a specific condition for the product of output and input matrix. Earlier studies indicate that even the linearised system is not ASPR. The two problems at hand are: 1) the system is non-minimum phase when flying with zero bank angle, and 2) whenever there is hybrid control, e.g., yaw control is established by combined reaction and aerodynamic control for the major part of flight, the second ASPR condition cannot be met. In this paper we look at both issues, the former related to the guidance system and the latter to the attitude-control system. It is concluded that whenever the nominal bank angle is zero, the passivity conditions can never be met, and guidance should be based on nominal commands and a redefinition of those whenever the error becomes too large. For the remaining part of the trajectory, the passivity conditions are marginally met, but it is proposed to add feedforward compensators to alleviate these conditions. The issue of hybrid control is avoided by redefining the controls with total control moments and adding a so-called control allocator. Deriving the passivity conditions for rotational motion, and evaluating these conditions along the trajectory shows that the (non-linear) winged entry vehicle is ASP. The sufficient conditions to apply SAC for attitude control are thus met.

  17. On Re-Entry Prediction of Near Earth Objects with Genetic Algorithm Using KS Elements

    NASA Astrophysics Data System (ADS)

    Sharma, R. K.; Anilkumar, A. K.; Xavier James Raj, M.; Sabarinath, A.

    2009-03-01

    The accurate orbit prediction of the near-Earth objects is an important requirement for the re-entry and the life time estimation. The method of Kustaanheimo and Stiefel (KS) total energy element equations is one of the powerful methods for orbit prediction. Recently, due to the reentries of large number of risk objects, which posses threat to the human life and property, a great concern is developed in the space scientific community. Consequently, the prediction of risk objects re-entry time and location has got much importance for the proper planning of mitigation strategies and hazard assessment. This paper discusses an integrated procedure for orbit life time prediction combining the KS elements and genetic algorithm (GA). The orbit prediction is carried out by numerically integrating the KS element equations. In this methodology, the ballistic coefficient is estimated from a set of observed orbital parameters in terms of the Two Line Elements (TLE) by minimizing the variance of the predicted re-entry time from different TLE using GA. A software, KSGEN, systematically developed in-house using KS elements and genetic algorithm is utilized for predicting the re-entry time of the risk objects. This software has been effectively used for the prediction of the re-entry time in the past seven re-entry exercise campaigns conducted by the Inter Agency Space Debris Coordination Committee (IADC). The predicted re-entry time matched quite well with the actual re-entry time for all the seven IADC re-entry campaigns. A detailed analysis is carried out with two case studies.

  18. A theoretical study of the initiation, maintenance and termination of gastric slow wave re-entry

    PubMed Central

    Du, Peng; Paskaranandavadivel, Niranchan; O’Grady, Greg; Tang, Shou-Jiang; Cheng, Leo K.

    2015-01-01

    Gastric slow wave dysrhythmias are associated with motility disorders. Periods of tachygastria associated with slow wave re-entry were recently recognized as one important dysrhythmia mechanism, but factors promoting and sustaining gastric re-entry are currently unknown. This study reports two experimental forms of gastric re-entry and presents a series of multi-scale models that define criteria for slow wave re-entry initiation, maintenance and termination. High-resolution electrical mapping was conducted in porcine and canine models and two spatiotemporal patterns of re-entrant activities were captured: single-loop rotor and double-loop figure-of-eight. Two separate multi-scale mathematical models were developed to reproduce the velocity and entrainment frequency of these experimental recordings. A single-pulse stimulus was used to invoke a rotor re-entry in the porcine model and a figure-of-eight re-entry in the canine model. In both cases, the simulated re-entrant activities were found to be perpetuated by tachygastria that was accompanied by a reduction in the propagation velocity in the re-entrant pathways. The simulated re-entrant activities were terminated by a single-pulse stimulus targeted at the tip of re-entrant wave, after which normal antegrade propagation was restored by the underlying intrinsic frequency gradient. Main findings: (i) the stability of re-entry is regulated by stimulus timing, intrinsic frequency gradient and conductivity; (ii) tachygastria due to re-entry increases the frequency gradient while showing decreased propagation velocity; (iii) re-entry may be effectively terminated by a targeted stimulus at the core, allowing the intrinsic slow wave conduction system to re-establish itself. PMID:25552487

  19. Inflatable Re-Entry Vehicle Experiment (IRVE) Design Overview

    NASA Technical Reports Server (NTRS)

    Hughes, Stephen J.; Dillman, Robert A.; Starr, Brett R.; Stephan, Ryan A.; Lindell, Michael C.; Player, Charles J.; Cheatwood, F. McNeil

    2005-01-01

    Inflatable aeroshells offer several advantages over traditional rigid aeroshells for atmospheric entry. Inflatables offer increased payload volume fraction of the launch vehicle shroud and the possibility to deliver more payload mass to the surface for equivalent trajectory constraints. An inflatable s diameter is not constrained by the launch vehicle shroud. The resultant larger drag area can provide deceleration equivalent to a rigid system at higher atmospheric altitudes, thus offering access to higher landing sites. When stowed for launch and cruise, inflatable aeroshells allow access to the payload after the vehicle is integrated for launch and offer direct access to vehicle structure for structural attachment with the launch vehicle. They also offer an opportunity to eliminate system duplication between the cruise stage and entry vehicle. There are however several potential technical challenges for inflatable aeroshells. First and foremost is the fact that they are flexible structures. That flexibility could lead to unpredictable drag performance or an aerostructural dynamic instability. In addition, durability of large inflatable structures may limit their application. They are susceptible to puncture, a potentially catastrophic insult, from many possible sources. Finally, aerothermal heating during planetary entry poses a significant challenge to a thin membrane. NASA Langley Research Center and NASA's Wallops Flight Facility are jointly developing inflatable aeroshell technology for use on future NASA missions. The technology will be demonstrated in the Inflatable Re-entry Vehicle Experiment (IRVE). This paper will detail the development of the initial IRVE inflatable system to be launched on a Terrier/Orion sounding rocket in the fourth quarter of CY2005. The experiment will demonstrate achievable packaging efficiency of the inflatable aeroshell for launch, inflation, leak performance of the inflatable system throughout the flight regime, structural

  20. Hypersonic Cruise and Re-Entry Radio Frequency Blackout Mitigation: Alleviating the Communications Blackout Problem

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    2017-01-01

    The work presented here will be a review of a NASA effort to provide a method to transmit and receive RF communications and telemetry through a re-entry plasma thus alleviating the classical RF blackout phenomenon.

  1. Re-entry into the true lumen from the subintimal space.

    PubMed

    Schneider, Peter A; Caps, Michael T; Nelken, Nicolas

    2013-08-01

    Endovascular reconstruction of the femoral and popliteal arteries is replacing femoral-popliteal bypass. This is made possible by subintimal recanalization to manage long chronic total occlusions. Re-entry into the true lumen is the most challenging step in this process. This article summarizes the techniques for re-entry into the true lumen in the superficial femoral and above- and below-the-knee popliteal arteries.

  2. Utilizing Weather RADAR for Rapid Location of Meteorite Falls and Space Debris Re-Entry

    NASA Technical Reports Server (NTRS)

    Fries, Marc D.

    2016-01-01

    This activity utilizes existing NOAA weather RADAR imagery to locate meteorite falls and space debris falls. The near-real-time availability and spatial accuracy of these data allow rapid recovery of material from both meteorite falls and space debris re-entry events. To date, at least 22 meteorite fall recoveries have benefitted from RADAR detection and fall modeling, and multiple debris re-entry events over the United States have been observed in unprecedented detail.

  3. Longitudinal stability analysis of a suborbital re-entry demonstrator for a deployable capsule

    NASA Astrophysics Data System (ADS)

    Iacovazzo, Michele; Carandente, Valerio; Savino, Raffaele; Zuppardi, Gennaro

    2015-01-01

    In the field of atmospheric re-entry technology several research and industrial projects are based on the design of deployable, umbrella-like Thermal Protection Systems (TPSs) and aero-brakes. These systems are made of flexible, high temperature resistant fabrics, folded at launch and deployed in space for de-orbit and re-entry operations. This technology is very promising for low cost research and industrial applications, but requires to be validated by experimental flight tests. The University of Naples "Federico II" is currently working on the development of different down-scaled technological demonstrators for this kind of capsule to be launched by different classes of sounding rockets. In the present work an aerodynamic longitudinal stability analysis for a possible, suborbital re-entry demonstrator, has been performed in continuum and rarefied regimes. The longitudinal stability behavior of the capsule, along the entire re-entry path, has been investigated in the whole range of angle of attack and, in particular, around the nominal and the reverse equilibrium re-entry attitudes (i.e. around 0° and 180°, respectively) to implement a proper re-entry strategy able not to compromise the effectiveness of the flying system.

  4. Ongoing Capabilities and Developments of Re-Entry Plasma Ground Tests at EADS-ASTRIUM

    NASA Technical Reports Server (NTRS)

    Jullien, Pierre

    2008-01-01

    During re-entry, spacecrafts are subjected to extreme thermal loads. On mars, they may go through dust storms. These external heat loads are leading the design of re-entry vehicles or are affecting it for spacecraft facing solid propellant jet stream. Sizing the Thermal Protection System require a good knowledge of such solicitations and means to model and reproduce them on earth. Through its work on European projects, ASTRIUM has developed the full range of competences to deal with such issues. For instance, we have designed and tested the heat-shield of the Huygens probe which landed on Titan. In particular, our plasma generators aim to reproduce a wide variety of re-entry conditions. Heat loads are generated by the huge speed of the probes. Such conditions cannot be fully reproduced. Ground tests focus on reproducing local aerothermal loads by using slower but hotter flows. Our inductive plasma torch enables to test little samples at low TRL. Amongst the arc-jets, one was design to test architecture design of ISS crew return system and others fit more severe re-entry such as sample returns or Venus re-entry. The last developments aimed in testing samples in seeded flows. First step was to design and test the seeding device. Special diagnostics characterizing the resulting flow enabled us to fit it to the requirements.

  5. Trajectory Design and Control for the Compton Gamma Ray Observatory Re-Entry

    NASA Technical Reports Server (NTRS)

    Hoge, Susan; Vaughn, Frank; Bauer, Frank H. (Technical Monitor)

    2000-01-01

    The Compton Gamma Ray Observatory (CGRO) controlled re-entry operation was successfully conducted in June of 2000. The surviving parts of the spacecraft landed in the Pacific Ocean within the predicted footprint. The design of the maneuvers to control the trajectory to accomplish this re-entry presented several challenges. These challenges included timing and duration of the maneuvers, fuel management, post maneuver position knowledge, collision avoidance with other spacecraft, accounting for the break-up of the spacecraft into several pieces with a wide range of ballistic coefficients, and ensuring that the impact footprint would remain within the desired landing area in the event of contingencies. This paper presents the initial re-entry trajectory design and the evolution of the design into the maneuver sequence used for the re-entry. The paper discusses the constraints on the trajectory design, the modifications made to the initial design and the reasons behind these modifications. Data from the re-entry operation are presented.

  6. Ongoing Capabilities and Developments of Re-Entry Plasma Ground Tests at EADS-ASTRIUM

    NASA Technical Reports Server (NTRS)

    Jullien, Pierre

    2008-01-01

    During re-entry, spacecrafts are subjected to extreme thermal loads. On mars, they may go through dust storms. These external heat loads are leading the design of re-entry vehicles or are affecting it for spacecraft facing solid propellant jet stream. Sizing the Thermal Protection System require a good knowledge of such solicitations and means to model and reproduce them on earth. Through its work on European projects, ASTRIUM has developed the full range of competences to deal with such issues. For instance, we have designed and tested the heat-shield of the Huygens probe which landed on Titan. In particular, our plasma generators aim to reproduce a wide variety of re-entry conditions. Heat loads are generated by the huge speed of the probes. Such conditions cannot be fully reproduced. Ground tests focus on reproducing local aerothermal loads by using slower but hotter flows. Our inductive plasma torch enables to test little samples at low TRL. Amongst the arc-jets, one was design to test architecture design of ISS crew return system and others fit more severe re-entry such as sample returns or Venus re-entry. The last developments aimed in testing samples in seeded flows. First step was to design and test the seeding device. Special diagnostics characterizing the resulting flow enabled us to fit it to the requirements.

  7. Risk Assessment During the Final Phase of an Uncontrolled Re-Entry

    NASA Astrophysics Data System (ADS)

    Gaudel, A.; Hourtolle, C.; Goester, J. F.; Fuentes, N.

    2013-09-01

    As French National Space Agency, CNES is empowered to monitor compliance with technical regulations of the French Space Operation Act, FSOA, and to take all necessary measures to ensure the safety of people, property, public health and environment for all space operations involving French responsibility at international level.Therefore, CNES developed ELECTRA that calculates the risk for ground population involved in three types of events: rocket launching, controlled re-entry and uncontrolled re-entry. For the first two cases, ELECTRA takes into account degraded cases due to a premature stop of propulsion.Major evolutions were implemented recently on ELECTRA to meet new users' requirements, like the risk assessment during the final phase of uncontrolled re-entry, that can be combined with the computed risk for each country involved by impacts.The purpose of this paper is to provide an overview of the ELECTRA method and main functionalities, and then to highlight these recent improvements.

  8. Application of the FADS system on the Re-entry Module

    NASA Astrophysics Data System (ADS)

    Zhen, Huang

    2016-07-01

    The aerodynamic model for Flush Air Data Sensing System (FADS) is built based on the surface pressure distribution obtained through the pressure orifices laid on specific positions of the surface,and the flight parameters,such as angle of attack,angle of side-slip,Mach number,free-stream static pressure and dynamic pressure are inferred from the aerodynamic model.The flush air data sensing system (FADS) has been used on several flight tests of aircraft and re-entry vehicle,such as,X-15,space shuttle,F-14,X-33,X-43A and so on. This paper discusses the application of the FADS on the re-entry module with blunt body to obtain high-precision aerodynamic parameters.First of all,a basic theory and operating principle of the FADS is shown.Then,the applications of the FADS on typical aircrafts and re-entry vehicles are described.Thirdly,the application mode on the re-entry module with blunt body is discussed in detail,including aerodynamic simulation,pressure distribution,trajectory reconstruction and the hardware shoule be used,such as flush air data sensing system(FADS),inertial navigation system (INS),data acquisition system,data storage system.Finally,ablunt module re-entry flight test from low earth orbit (LEO) is planned to obtain aerodynamic parameters and amend the aerodynamic model with this FADS system data.The results show that FADS system can be applied widely in re-entry module with blunt bodies.

  9. Re-Entry Point Targeting for LEO Spacecraft using Aerodynamic Drag

    NASA Technical Reports Server (NTRS)

    Omar, Sanny; Bevilacqua, Riccardo; Fineberg, Laurence; Treptow, Justin; Johnson, Yusef; Clark, Scott

    2016-01-01

    Most Low Earth Orbit (LEO) spacecraft do not have thrusters and re-enter atmosphere in random locations at uncertain times. Objects pose a risk to persons, property, or other satellites. Has become a larger concern with the recent increase in small satellites. Working on a NASA funded project to design a retractable drag device to expedite de-orbit and target a re-entry location through modulation of the drag area. Will be discussing the re-entry point targeting algorithm here.

  10. Exploring Efficacy in Negotiating Support: Women Re-Entry Students in Higher Education

    ERIC Educational Resources Information Center

    Filipponi-Berardinelli, Josephine Oriana

    2013-01-01

    The existing literature on women re-entry students reveals that women students concurrently struggle with family, work, and sometimes health issues. Women students often do not receive adequate support from their partners or from other sources in helping manage the multiple roles that compete for their time, and often face constraints that affect…

  11. Trajectory Design and Control for the Compton Gamma Ray Observatory Re-Entry

    NASA Technical Reports Server (NTRS)

    Hoge, Susan; Vaughn, Frank J., Jr.

    2001-01-01

    The Compton Gamma Ray Observatory (CGRO) controlled re-entry operation was successfully conducted in June of 2000. The surviving parts of the spacecraft landed in the Pacific Ocean within the nominal impact target zone. The design of the maneuvers to control the trajectory to accomplish this re-entry presented several challenges. These challenges included the timing and duration of the maneuvers, propellant management, post-maneuver state determination, collision avoidance with other spacecraft, accounting for the break-up of the spacecraft into several pieces with a wide range of ballistic coefficients, and ensuring that the impact footprint would remain within the desired impact target zone in the event of contingencies. This paper presents the initial re-entry trajectory design and traces the evolution of that design into the maneuver sequence used for the re-entry. The paper also discusses the spacecraft systems and operational constraints imposed on the trajectory design and the required modifications to the initial design based on those constraints. Data from the reentry operation are also presented.

  12. Optimization of Observation Strategy to Improve Re-entry Prediction of Objects in HEO

    NASA Astrophysics Data System (ADS)

    Rasotto, M.; Di Mauro, G.; Massari, M.; Di Lizia, P.; Armellin, R.; Funke, Q.; Flohrer, T.

    2016-09-01

    During the last decade the number of space debris moving on high elliptical orbit (HEO) has grown fast. Many of these resident space objects (RSO) consist of medium and large spent upper stages of launch vehicles, whose atmosphere re-entry might violate on-ground casualty risk constraints. Increasing the accuracy of re-entry predictions for this class of RSO is therefore a key issue to limit the hazards on the Earth assets. Traditional computational methods are mainly based on the exploitation of Two Line Elements (TLEs), provided by the United States Strategic Command (USSTRATCOM) and currently the only public data source available for these kind of analyses. TLE data however, are characterized by low accuracies, and in general come without any uncertainty information, thus limiting the achievable precision of the re-entry estimates. Better results on the other hand, can be obtained through the exploitation of observational data provided by one or more Earth sensors. Despite the benefits, this approach introduces a whole new set of complexities, mainly related with the design of proper observation campaigns. This paper presents a method based on evolutionary algorithms, for the optimization of observation strategies. The effectiveness of the proposed approach is demonstrated through dedicated examples, in which re-entry predictions, attainable with existing and ideal sensor architectures, are compared with corresponding results derived from TLE data.

  13. Northern Kentucky University ReEntry Center, 1980-1990. 10 Year Anniversary Celebration.

    ERIC Educational Resources Information Center

    Northern Kentucky Univ., Highland Heights.

    The original poems and articles contained in this publication were submitted by individuals who have either been through the programs offered by the ReEntry Center at Northern Kentucky University or have otherwise had their lives touched and changed by the center's existence. They are intended to illustrate the growth and achievement that these…

  14. Re-entry Flight Experiments Lessons Learned - The Atmospheric Reentry Demonstrator ARD

    DTIC Science & Technology

    2007-06-01

    the complete calorimeter has been developped from which an inverse method has been derived [R7]. The Thermal Mathematical Model accounts for external...re-entry vehicle that in spite of its similitude with a simple axisymetrical Apollo shape, was found to be rather complex to identify; its large

  15. ENTRYSAT: A 3U Cubesat to Study the Re-Entry Atmospheric Environment

    NASA Astrophysics Data System (ADS)

    Garcia, R. F.; Chaix, J.; Mimoun, D.; EntrySat student Team

    2014-04-01

    The EntrySat is a 3U CubeSat designed to study the uncontrolled atmospheric re-entry. The project, developed by ISAE in collaboration with ONERA, is funded by CNES and is intended to be launched in January 2016, in the context of the QB50 network. The scientific goal is to relate the kinematics of the satellite with the aerothermodynamic environment during re-entry. In particular, data will be compared with the computations of MUSIC/FAST, a new 6-degree of freedom code developed by ONERA to predict the trajectory of space debris. According to these requirements, the satellite will measure the temperature, pressure, heat flux, and drag force during re-entry, as well as the trajectory and attitude of the satellite. One of the major technological challenges is the retrieval of data during the re-entry phase, which will be based on the Iridium satellite network. The system design is based on the use of commercial COTS components, and is mostly developed by students from ISAE. As such, the EntrySat has an important educational value in the formation of young engineers.

  16. Art Concept - Apollo VIII - Command Module (CM) - Re-Entry Orientation

    NASA Image and Video Library

    1968-01-01

    S68-55292 (August 1968) --- A North American Rockwell Corporation artist's concept depicting the Apollo Command Module (CM), oriented in a blunt-end-forward attitude, re-entering Earth's atmosphere after returning from a lunar landing mission. Note the change in color caused by the extremely high temperatures encountered upon re-entry.

  17. International Space Station as an Observation Platform for Hypersonic Re-Entry of its Visiting Vehicles

    NASA Technical Reports Server (NTRS)

    Bacon, John B.

    2001-01-01

    The International Space Station (ISS) will receive an armada of visiting supply vehicles during its life in orbit. Over 500 tons of material will be destroyed in targeted re-entries of these vehicles. Because all such re-entries lie in the same orbital plane of the station, and because the visiting vehicles typically deorbit within a few hours of departure, the ISS will usually be within sight of the re-entry process, at a range of only 300-600 kilometers. This vantage point offers an unprecedented opportunity for systematically measuring hypersonic destructive processes. This paper examines the integrated operational constraints of the ISS, its supply vehicles, and candidate sensors which can be employed in the scientific observation of the re-entry process. It is asserted the ISS program has the potential to reduce the worldwide risks from future deorbiting spacecraft, through systematic experimental characterization of the factors which affect the rupture, debris survival, and footprint size of its visiting vehicle fleet.

  18. Procedural and Early Outcomes of Two Re-entry Devices for Subintimal Recanalization of Aortoiliac and Femoropopliteal Chronic Total Occlusions

    PubMed Central

    Vuruskan, Ertan

    2017-01-01

    Background and Objectives Subintimal angioplasty is a common treatment choice for chronic total occlusions (CTO) in the iliac and femoropopliteal arteries. This article describes the technical aspects and early outcomes of two different re-entry devices and comparison with manual re-entry technique. Subjects and Methods A retrospective review of 61 patients (re-entry group) treated with Outback or Pioneer Plus catheters was carried out. A matched cohort of patients (n=62) who underwent lower extremity interventions without the use of re-entry devices (manual re-entry group) were also analyzed (overall 123 patients were analyzed). Procedural success, procedural durations, patency estimates, ankle-brachial indices, and complications were analyzed. Results Sixty-one patients underwent Outback or Pioneer Plus guided subintimal recanalization. After the procedure, ankle-brachial indices significantly increased in all patients during follow-up. Primary patency for the entire cohort was 83% in the first month. When the re-entry device group was compared with manual re-entry group, no difference was found with respect to success, complication, and patencies between the two groups during follow-up. However, procedure duration and the amount of contrast agent used was significantly decreased in re-entry groups (p<0.001). Also, re-entry time was significantly decreased in Pioneer plus group according to Outback group (p<0.001) Conclusion Recanalization of CTO using re-entry devices for aortoiliac or femoropopliteal arteries is safe and effective. These devices shorten the procedure time, the re-entry time, reduce radiation risk, and reduce the amount of contrast agent employed. PMID:28154596

  19. Airborne Observation of the Hayabusa Sample Return Capsule Re-Entry

    NASA Technical Reports Server (NTRS)

    Grinstead, Jay H.; Jenniskens, Peter M.; Cassell, Alan M.; Albers, Jim; Winterm Michael

    2011-01-01

    The Japan Aerospace Exploration Agency (JAXA) recently completed their Hayabusa asteroid exploration mission. Launched in 2003, Hayabusa made contact with, and retrieved a sample from, the near-Earth asteroid Itokawa in 2005. The sample return capsule (SRC) re-entered over the Woomera Test Range (WTR) in southern Australia on June 13, 2010, at approximately 11:21 pm local time (09:51 UTC). The SRC re-entry velocity was 12.2 km/s, making it the second-fastest Earth return velocity behind NASA s Stardust sample return capsule re-entry in 2006. From a space technology development perspective, Hayabusa s re-entry functioned as a rare flight experiment of an entry vehicle and its thermal protection system. In collaboration with the SETI Institute, NASA deployed its DC-8 airborne laboratory and a team of international researchers to Australia to observe the re-entry of the SRC. The use of an airborne platform enables observation above most clouds and weather and greatly diminishes atmospheric absorption of the optical signals. The DC-8 s flight path was engineered and flown to provide a view of the spacecraft that bracketed the heat pulse to the capsule. A suite of imaging instruments on board the DC-8 successfully recorded the luminous portion of the re-entry event. For approximately 70 seconds, the spectroscopic and radiometric instruments acquired images and spectra of the capsule, its wake, and destructive re-entry of the spacecraft bus. Figure 1 shows a perspective view of the WTR, the SRC re-entry trajectory, and the flight path of the DC-8. The SRC was jettisoned from the spacecraft bus approximately 3 hours prior to entry interface. Due to thruster failures on the spacecraft, it could not be diverted from the entry path and followed the trajectory of the SRC, where it burned up in the atmosphere between approximately 100 and 50 km altitude. Fortuitously, the separation distance between the spacecraft and SRC was sufficient to clearly resolve the SRC from the

  20. Acute amiodarone promotes drift and early termination of spiral wave re-entry.

    PubMed

    Nakagawa, Harumichi; Honjo, Haruo; Ishiguro, Yuko S; Yamazaki, Masatoshi; Okuno, Yusuke; Harada, Masahide; Takanari, Hiroki; Sakuma, Ichiro; Kamiya, Kaichiro; Kodama, Itsuo

    2010-07-01

    Intravenous application of amiodarone is commonly used in the treatment of life-threatening arrhythmias, but the underlying mechanism is not fully understood. The purpose of the present study is to investigate the acute effects of amiodarone on spiral wave (SW) re-entry, the primary organization machinery of ventricular tachycardia/fibrillation (VT/VF), in comparison with lidocaine. A two-dimensional ventricular myocardial layer was obtained from 24 Langendorff-perfused rabbit hearts, and epicardial excitations were analyzed by high-resolution optical mapping. During basic stimulation, amiodarone (5 microM) caused prolongation of action potential duration (APD) by 5.6%-9.1%, whereas lidocaine (15 microM) caused APD shortening by 5.0%-6.4%. Amiodarone and lidocaine reduced conduction velocity similarly. Ventricular tachycardias induced by DC stimulation in the presence of amiodarone were of shorter duration (sustained-VTs >30 s/total VTs: 2/58, amiodarone vs 13/52, control), whereas those with lidocaine were of longer duration (22/73, lidocaine vs 14/58, control). Amiodarone caused prolongation of VT cycle length and destabilization of SW re-entry, which is characterized by marked prolongation of functional block lines, frequent wavefront-tail interactions near the rotation center, and considerable drift, leading to its early annihilation via collision with anatomical boundaries. Spiral wave re-entry in the presence of lidocaine was more stabilized than in control. In the anisotropic ventricular myocardium, amiodarone destabilizes SW re-entry facilitating its early termination. Lidocaine, in contrast, stabilizes SW re-entry resulting in its persistence.

  1. IXV re-entry demonstrator: Mission overview, system challenges and flight reward

    NASA Astrophysics Data System (ADS)

    Angelini, Roberto; Denaro, Angelo

    2016-07-01

    The Intermediate eXperimental Vehicle (IXV) is an advanced re-entry demonstrator vehicle aimed to perform in-flight experimentation of atmospheric re-entry enabling systems and technologies. The IXV integrates key technologies at the system level, with significant advancements on Europe's previous flying test-beds. The project builds on previous achievements at system and technology levels, and provides a unique and concrete way of establishing and consolidating Europe's autonomous position in the strategic field of atmospheric re-entry. The IXV mission and system objectives are the design, development, manufacturing, assembling and on-ground to in-flight verification of an autonomous European lifting and aerodynamically controlled reentry system, integrating critical re-entry technologies at system level. Among such critical technologies of interest, special attention is paid to aerodynamic and aerothermodynamics experimentation, including advanced instrumentation for aerothermodynamics phenomena investigations, thermal protections and hot-structures, guidance, navigation and flight control through combined jets and aerodynamic surfaces (i.e. flaps), in particular focusing on the technologies integration at system level for flight. Following the extensive detailed design, manufacturing, qualification, integration and testing of the flight segment and ground segment elements, IXV has performed a full successful flight on February 11th 2015. After the launch with the VEGA launcher form the CSG spaceport in French Guyana, IXV has performed a full nominal mission ending with a successful splashdown in the Pacific Ocean. During Flight Phase, the IXV space and ground segments worked perfectly, implementing the whole flight program in line with the commanded maneuvers and trajectory prediction, performing an overall flight of 34.400 km including 7.600 km with hot atmospheric re-entry in automatic guidance, concluding with successful precision landing at a distance of ~1

  2. Aerothermodynamics of generic re-entry vehicle with a series of aerospikes at nose

    NASA Astrophysics Data System (ADS)

    Yadav, Rajesh; Velidi, Gurunadh; Guven, Ugur

    2014-03-01

    Re-entry of a blunt nosed vehicle is one of the most intriguing problems in any space programme. Especially in light of various space tourism possibilities, there are many works concerning re-entry of commercial blunt nosed space vehicles. In this paper, a generic blunt body re-entry model represented by a hemisphere-cylinder, fitted axisymmetrically with an aerodisk aerospike at the nose is investigated numerically with commercially available control volume based axisymmetric flow solver. The scaled down re-entry model has a base diameter of 40 mm and an overall length of 100 mm. A 6 mm diameter aerospike fitted axisymmetrically at the nose has a hemispherical cap from which another aerospike of 4 mm diameter protrudes which again has a hemispherical cap. Two dimensional compressible, axisymmetric Navier Stokes Equations are solved for a turbulent hypersonic flow of a 5 species, chemically reacting air in thermal equilibrium with free stream conditions of Mach no., static pressure and temperature of 10.1, 16,066 Pa and 216.65 K, respectively. The results are compared with that of re-entry model without any aerospike. Among the cases investigated, the spiked blunt body having two aerospikes in series with lengths l1 and l2 equal to 30 and 20 respectively and overall length-to-diameter ratio of 1.5 showed a favourable reduction in the peak reattachment heat flux along with high reduction in aerodynamic drag and thus stands as a prospective case for blunt body nose configuration for hypersonic flight.

  3. A Novel 'Cheese Wire' Technique for Stent Positioning Following Difficult Iliac Artery Subintimal Dissection and Aortic Re-Entry

    SciTech Connect

    Watkinson, A. F.

    2009-07-15

    Subintimal wire dissection is a well-established method for traversing difficult vascular occlusions. This technique relies on re-entry of the true lumen distal to the occlusion, which may be difficult in diseased vessels with significant calcification. This case report describes a novel 'cheese wire' technique to allow stent positioning without the use of proprietary re-entry devices.

  4. State Policies Affecting the "Adult Re-Entry Pipeline" in Postsecondary Education: Results of a Fifty-State Inventory

    ERIC Educational Resources Information Center

    Boeke, Marianne; Zis, Stacey; Ewell, Peter

    2011-01-01

    With support from the Bill and Melinda Gates Foundation, the National Center for Higher Education Management Systems (NCHEMS) is engaged in a two year project centered on state policies that foster student progression and success in the "adult re-entry pipeline." The adult re-entry pipeline consists of the many alternative pathways to…

  5. Wind Tunnel Aero-Heating and Material Destruction Tests for Improved Debris Re-Entry Analysis

    NASA Astrophysics Data System (ADS)

    Koppenwallner, G.; Lips, T.; Alwes, D.

    2009-03-01

    During the S/C re-entry destruction fragments of irregular geometry are released. One finds spheres, boxes and cylinders, which may be hollow and which are flying in tumbling motion. The experimental database on such bodies is limited. Therefore heat transfer test have been conducted in the hypersonic vacuum wind tunnel V2G of DLR Göttingen. With a special model support also rotating models could be tested.Another study objective was the thermal destruction of selected materials and CFRP components under simulated re-entry heat loads. In use are solid CFRP structures, honeycombs with CFRP facesheets, or thin walled titanium tanks with external CFRP reinforcements. The destruction of multilayer structures may be completely different to solid thick CFRP. Therefore samples of 12 CFRP and CFRP honeycombs have been tested in the LBK 2 arc jet facility of DLR.

  6. Recovery, Transportation and Acceptance to the Curation Facility of the Hayabusa Re-Entry Capsule

    NASA Technical Reports Server (NTRS)

    Abe, M.; Fujimura, A.; Yano, H.; Okamoto, C.; Okada, T.; Yada, T.; Ishibashi, Y.; Shirai, K.; Nakamura, T.; Noguchi, T.; Okazaki, R.; Zolensky, M.; Sandford, S.; Ireland, T.; Ueno, M.; Mukai, T.; Yoshikawa, M.; Yamada, T.; Kuninaka, H.; Kawaguchi, J.

    2011-01-01

    The "Hayabusa" re-entry capsule was safely carried into the clean room of Sagamihara Planetary Sample Curation Facility in JAXA on June 18, 2010. After executing computed tomographic (CT) scanning, removal of heat shield, and surface cleaning of sample container, the sample container was enclosed into the clean chamber. After opening the sample container and residual gas sampling in the clean chamber, optical observation, sample recovery, sample separation for initial analysis will be performed. This curation work is continuing for several manths with some selected member of Hayabusa Asteroidal Sample Preliminary Examination Team (HASPET). We report here on the 'Hayabusa' capsule recovery operation, and transportation and acceptance at the curation facility of the Hayabusa re-entry capsule.

  7. Thermal Analysis and Design of Multi-layer Insulation for Re-entry Aerodynamic Heating

    NASA Technical Reports Server (NTRS)

    Daryabeigi, Kamran

    2001-01-01

    The combined radiation/conduction heat transfer in high-temperature multi-layer insulations was modeled using a finite volume numerical model. The numerical model was validated by comparison with steady-state effective thermal conductivity measurements, and by transient thermal tests simulating re-entry aerodynamic heating conditions. A design of experiments technique was used to investigate optimum design of multi-layer insulations for re-entry aerodynamic heating. It was found that use of 2 mm foil spacing and locating the foils near the hot boundary with the top foil 2 mm away from the hot boundary resulted in the most effective insulation design. A 76.2 mm thick multi-layer insulation using 1, 4, or 16 foils resulted in 2.9, 7.2, or 22.2 percent mass per unit area savings compared to a fibrous insulation sample at the same thickness, respectively.

  8. Behavior of HfB2-SiC Materials in Simulated Re-Entry Environments

    NASA Technical Reports Server (NTRS)

    Ellerby, Don; Beckman, Sarah; Irby, Edward; Johnson, Sylvia M.; Gunsman, Michael; Gasch, Matthew; Ridge, Jerry; Martinez, Ed; Squire, Tom; Olejniczak, Joe

    2003-01-01

    The objectives of this research are to: 1) Investigate the oxidation/ablation behavior of HfB2/SiC materials in simulated re-entry environments; 2) Use the arc jet test results to define appropriate use environments for these materials for use in vehicle design. The parameters to be investigated include: surface temperature, stagnation pressure, duration, number of cycles, and thermal stresses.

  9. Optimal Re-Entry Trajectory Terminal State Due to Variations in Waypoint Locations

    DTIC Science & Technology

    2008-12-01

    of path constraints or vehicle mass n number of states p number of event constraints (boundary conditions) λ costate Lagrange multiplier H...OPENPOCS Open Pseudospectral Optimal Control Software PSCOL Pseudospectral Collocation RLV Reusable Launch Vehicle RV Re-entry Vehicle RPM Radau ...0 0, , , 0f fx t t x t tφ = (2.3) and the path constraints ( ) ( )( ), , 0C x t u t t ≤ (2.4) 7 where ( ) ( ) n p m x C C C φ

  10. Test of Re-Entry Systems at Estrange Using Sounding Rockets and Stratospheric Balloons

    NASA Astrophysics Data System (ADS)

    Lockowandt, C.; Abrahamsson, M.; Florin, G.

    2015-09-01

    Stratospheric balloons and sounding rockets can provide an ideal in-flight platform for performing re-entry and other high speed tests off different types of vehicles and techniques. They are also ideal platforms for testing different types of recovery systems such as airbrakes and parachutes. This paper expands on some examples of platforms and missions for drop tests from balloons as well as sounding rockets launched from Esrange Space Center, a facility run by Swedish Space Corporation SSC in northern Sweden.

  11. Predictors of re-entry into the child protection system in Singapore: a cumulative ecological-transactional risk model.

    PubMed

    Li, Dongdong; Chu, Chi Meng; Ng, Wei Chern; Leong, Wai

    2014-11-01

    This study examines the risk factors of re-entry for 1,750 child protection cases in Singapore using a cumulative ecological-transactional risk model. Using administrative data, the present study found that the overall percentage of Child Protection Service (CPS) re-entry in Singapore is 10.5% based on 1,750 cases, with a range from 3.9% (within 1 year) to 16.5% (within 8 years after case closure). One quarter of the re-entry cases were observed to occur within 9 months from case closure. Seventeen risk factors, as identified from the extant literature, were tested for their utility to predict CPS re-entry in this study using a series of Cox regression analyses. A final list of seven risk factors (i.e., children's age at entry, case type, case closure result, duration of case, household income, family size, and mother's employment status) was used to create a cumulative risk score. The results supported the cumulative risk model in that higher risk score is related to higher risk of CPS re-entry. Understanding the prevalence of CPS re-entry and the risk factors associated with re-entry is the key to informing practice and policy in a culturally relevant way. The results from this study could then be used to facilitate critical case management decisions in order to enhance positive outcomes of families and children in Singapore's care system.

  12. TRMM Re-Entry Planning: Attitude Determination and Control During Thruster Modes

    NASA Technical Reports Server (NTRS)

    DeWeese, Keith

    2005-01-01

    The Tropical Rainfall Measuring Mission (TRMM) spacecraft has been undergoing design for a controlled re-entry to Earth. During simulation of the re-entry plan, there was evidence of errors in the attitude determination algorithms during thruster modes. These errors affected the bum efficiency, and thus planning, during re-entry. During thruster modes, the spacecraft attitude is controlled off of integrated Gyro Error Angles that were designed to closely follow the nominal spacecraft pointing frame (Tip Frame). These angles, however, were not exactly mapped to the Tip Frame from the Body Frame. Additionally, in the initial formulation of the thruster mode attitude determination algorithms, several assumptions and approximations were made to conserve processor speed. These errors became noticeable and significant when simulating bums of much longer duration (-10 times) than had been produced in flight. A solution is proposed that uses attitude determination information from a propagated extended Kalman filter that already exists in the TRMM thruster modes. This attitude information is then used to rotate the Gyro Error Angles into the Tip Frame. An error analysis is presented that compares the two formulations. The new algorithm is tested using the TRMM High-Fidelity Simulator and verified with the TRMM Software Testing and Training Facility. Simulation results for both configurations are also presented.

  13. A constant gain Kalman filter approach for the prediction of re-entry of risk objects

    NASA Astrophysics Data System (ADS)

    Anilkumar, A. K.; Ananthasayanam, M. R.; Subba Rao, P. V.

    2007-11-01

    The accurate estimation of the predicted re-entry time of decaying space debris objects is very important for proper planning of mitigation strategies and hazard assessment. This paper highlights the implementation strategies adopted for the online re-entry prediction using Kalman filter approach with constant gains with the states being the semi-major axis, eccentricity and ballistic coefficient and using the measurements of the apogee height and perigee height derived from the Two Line Elements provided by agencies like USSPACECOM. Only a very simple model is utilised for the orbit propagation and a basic feature of the present approach is that any unmodellable state and measurement errors can be accounted for by adjusting the Kalman gains which are chosen based on a suitable cost function. In this paper we provide the details of validating this approach by utilising three re-entries of debris objects, namely, US Sat. No. 25947, SROSS-C2 Satellite and COSMOS 1043 rocket body. These three objects re-entered the Earth's atmosphere on 4th March 2000, 12th July 2001 and 19th January 2002, respectively.

  14. Study and Development of a Sub-Orbital Re-Entry Demonstrator

    NASA Astrophysics Data System (ADS)

    Savino, R.

    The Italian and European Space Agencies are supporting a research programme, developed in Campania region by a cluster of industries, research institutes and universities, on a low-cost re-entry capsule, able to return payloads from the ISS to Earth and/or to perform short-duration scientific missions in Low Earth Orbit (LEO). The ballistic capsule is characterized by a deployable, disposable "umbrella-like" heat shield that allows relatively small dimensions at launch and a sufficient exposed surface area in re-entry conditions, reducing the ballistic coefficient and leading to acceptable heat fluxes, mechanical loads and final descent velocity. ESA is supporting a preliminary study to develop a flight demonstrator of the capsule to be embarked as a secondary payload onboard a sub-orbital sounding rocket. The deployable thermal protection system concept may be applied to future science and robotic exploration mission requiring planetary entry and, possibly also to missions in the framework of Human Space flight, requiring planetary entry or re-entry. The technology offers also an interesting potential for aerobraking, aerocapture and for de-orbiting. This paper summarizes the results of these activities, which are being more and more refined as the work proceeds, including the definition and analysis of the mission scenario, the aerodynamic, aerothermodynamic, mechanical and structural analyses and the technical definition of avionics, instrumentation and main subsystems.

  15. Spectroscopic Observation of the Re-Entry Capsule of HAYABUSA Spacecraft

    NASA Astrophysics Data System (ADS)

    Ohnishi, Kouji; Watanabe, Jun-Ichi; Sato, Mikiya; Ohkawa, Takuya; Ebizuka, Noboru

    2011-10-01

    We performed low-resolution spectroscopic observations of the capsule of the HAYABUSA spacecraft during re-entry into the Earth's atmosphere on 2010 June 13 UT as an artificial meteor. We obtained the photometric magnitude of the HAYABUSA capsule using zeroth-order spectra. The efficiency of the zeroth-order spectra was too low for us to measure the magnitude of the capsule without any saturation at all times. The altitude at the maximal flux of the capsule was at around 56 km (13h52m19s.81 UT), which is almost similar to the case GENESIS, i.e., the maximal flux at around 55 km. We examined the change in the spectrum shape of the capsule as a function of its altitude, and investigated the emission from the shock layer and the blackbody radiation from the surface of the capsule. It is found that the shock-layer emission was dominant, and/or on the same order of the blackbody radiation at the early phase of re-entry; also, the emission from blackbody radiation was dominant during the last phase of re-entry. We measured the surface temperature of the capsule along the trajectory; during the last phase before dark flight, we found that the blackbody temperature of the capsule was 3100 ± 300 K at an altitude of around 50 km, and 2400 ± 300 K at an altitude of around 40 km.

  16. Airborne Observation of the Hayabusa Sample Return Capsule Re-Entry

    NASA Technical Reports Server (NTRS)

    Grinstead, Jay H.; Jenniskens, Peter; Cassell, Alan M.; Albers, James; Winter, Michael W.

    2011-01-01

    NASA Ames Research Center and the SETI Institute collaborated on an effort to observe the Earth re-entry of the Japan Aerospace Exploration Agency's Hayabusa sample return capsule. Hayabusa was an asteroid exploration mission that retrieved a sample from the near-Earth asteroid Itokawa. Its sample return capsule re-entered over the Woomera Prohibited Area in southern Australia on June 13, 2010. Being only the third sample return mission following NASA's Genesis and Stardust missions, Hayabusa's return was a rare opportunity to collect aerothermal data from an atmospheric entry capsule returning at superorbital speeds. NASA deployed its DC-8 airborne laboratory and a team of international researchers to Australia for the re-entry. For approximately 70 seconds, spectroscopic and radiometric imaging instruments acquired images and spectra of the capsule, its wake, and destructive re-entry of the spacecraft bus. Once calibrated, spectra of the capsule will be interpreted to yield data for comparison with and validation of high fidelity and engineering simulation tools used for design and development of future atmospheric entry system technologies. A brief summary of the Hayabusa mission, the preflight preparations and observation mission planning, mission execution, and preliminary spectral data are documented.

  17. Study on Mini Re-Entry System Using Deployable Membrane Aeroshell

    NASA Astrophysics Data System (ADS)

    Koyama, Masashi; Suzuki, Kojiro; Imamura, Osamu; Yamada, Kazuhiko

    An aeroshell made from membrane material have an advantage of reduction in the aerodynamic heating, because its small mass and large area enable us to make the low-ballistic-coefficient flight, in which the vehicle decelerates at very high altitude with low atmospheric density. In this paper, we propose a new concept of mini re-entry system for small satellites. This vehicle is called "FEATHER" (Flexible Expanded Aeroshell with Tiny payload Harness for Entry and Recovery). "FEATHER" is a novel re-entry and recovery system, featuring the autonomous aeroshell deployment, the low-ballistic-coefficient re-entry with less severe aerodynamicc heating and so on. FEATHER is composed of the membrane aeroshell made from the high-temperature cloth called ZYLON®, an outer frame made of Shape Memory Alloy (SMA) and a payload. When the aeroshell receives the aerodynamic heating, the temperature of SMA frame rises and restores the circular shape as memorized beforehand. Then the membrane aeroshell is automatically deployed. Therefore the vehicle can achieve the low-ballistic-coefficient flight with a drastic reduction in the aerodynamic heating without any additional sensors, controllers and actuators. The preliminary studies made on FEATHER system so far including the hypersonic wind tunnel experiments are presented in this paper.

  18. Targeting of cytosolic phospholipase A2α impedes cell cycle re-entry of quiescent prostate cancer cells.

    PubMed

    Yao, Mu; Xie, Chanlu; Kiang, Mei-Yee; Teng, Ying; Harman, David; Tiffen, Jessamy; Wang, Qian; Sved, Paul; Bao, Shisan; Witting, Paul; Holst, Jeff; Dong, Qihan

    2015-10-27

    Cell cycle re-entry of quiescent cancer cells has been proposed to be involved in cancer progression and recurrence. Cytosolic phospholipase A2α (cPLA2α) is an enzyme that hydrolyzes membrane glycerophospholipids to release arachidonic acid and lysophospholipids that are implicated in cancer cell proliferation. The aim of this study was to determine the role of cPLA2α in cell cycle re-entry of quiescent prostate cancer cells. When PC-3 and LNCaP cells were rendered to a quiescent state, the active form of cPLA2α with a phosphorylation at Ser505 was lower compared to their proliferating state. Conversely, the phospho-cPLA2α levels were resurgent during the induction of cell cycle re-entry. Pharmacological inhibition of cPLA2α with Efipladib upon induction of cell cycle re-entry inhibited the re-entry process, as manifested by refrained DNA synthesis, persistent high proportion of cells in G0/G1 and low percentage of cells in S and G2/M phases, together with a stagnant recovery of Ki-67 expression. Simultaneously, Efipladib prohibited the emergence of Skp2 while maintained p27 at a high level in the nuclear compartment during cell cycle re-entry. Inhibition of cPLA2α also prevented an accumulation of cyclin D1/CDK4, cyclin E/CDK2, phospho-pRb, pre-replicative complex proteins CDC6, MCM7, ORC6 and DNA synthesis-related protein PCNA during induction of cell cycle re-entry. Moreover, a pre-treatment of the prostate cancer cells with Efipladib during induction of cell cycle re-entry subsequently compromised their tumorigenic capacity in vivo. Hence, cPLA2α plays an important role in cell cycle re-entry by quiescent prostate cancer cells.

  19. Sensitivity analysis and probabilistic re-entry modeling for debris using high dimensional model representation based uncertainty treatment

    NASA Astrophysics Data System (ADS)

    Mehta, Piyush M.; Kubicek, Martin; Minisci, Edmondo; Vasile, Massimiliano

    2017-01-01

    Well-known tools developed for satellite and debris re-entry perform break-up and trajectory simulations in a deterministic sense and do not perform any uncertainty treatment. The treatment of uncertainties associated with the re-entry of a space object requires a probabilistic approach. A Monte Carlo campaign is the intuitive approach to performing a probabilistic analysis, however, it is computationally very expensive. In this work, we use a recently developed approach based on a new derivation of the high dimensional model representation method for implementing a computationally efficient probabilistic analysis approach for re-entry. Both aleatoric and epistemic uncertainties that affect aerodynamic trajectory and ground impact location are considered. The method is applicable to both controlled and un-controlled re-entry scenarios. The resulting ground impact distributions are far from the typically used Gaussian or ellipsoid distributions.

  20. Scarab -a Multi-Disciplinary Code for Destruction Analysis of Space-Craft during Re-Entry

    NASA Astrophysics Data System (ADS)

    Koppenwallner, G.; Fritsche, B.; Lips, T.; Klinkrad, H.

    2005-02-01

    The uncontrolled, destructive re-entry of satellites and the related ground risk due to fragments reaching the ground have become of increased interest during the past years. The software system SCARAB (Spacecraft Atmospheric Re-entry and Aerothermal Break-up) is designed to calculate the destruction of a spacecraft during re-entry. Development of this code system started in 1995 and was conducted by HTG within the frame of various ESOC contracts with ITAM in Novosibirsk as continuous partner. The modular software system provide modules for satellite modelling and re-entry analysis The analysis modules combine aerodynamic/aero-thermal loads, 6-D flight dynamic, heat conduction, destruction by melting or fracture and the fragment tracking till ground impact SCARAB has been applied to many projects like ARIANE 5, ATV, ROSAT, Beppo SAX and Terrasar.

  1. Canal switch and re-entry phenomenon in benign paroxysmal positional vertigo: difference between immediate and delayed occurrence.

    PubMed

    Dispenza, F; DE Stefano, A; Costantino, C; Rando, D; Giglione, M; Stagno, R; Bennici, E

    2015-04-01

    This prospective study was designed to evaluate the differences between immediate and delayed canal re-entry of otoliths after therapeutic manoeuvres in patients with benign paroxysmal positional vertigo (BPPV). A total of 196 patients with BPPV were visited and 127 matched our inclusion criteria. The mean age was 54.74 years. The horizontal semicircular canal (HSC) was involved in 30 cases and the posterior semicircular canal (PSC) in 97 patients. Patients with hearing loss in the ear affected by BPPV have a more recurrent form, compared to those with normal hearing. An immediate canal re-entry was recorded in 3 patients with HSC BPPV, all with geotropic nystagmus. In 7 patients with PSC BPPV, the immediate canal re-entry was detected and the delayed form was noted in 5 patients. The patients with the delayed canal re-entry underwent more than 2 previous manoeuvres. The canal re-entry was not related to the manoeuvre performed. The timing of the Dix-Hallpike test to verify the resolution of the BPPV had a significant role in immediate canal re-entry. A recurrence in the follow-up at least one month after treatment was recorded in 20 patients and was more frequent in patients that had canal re-entry. The canal re-entry or canal switch is a clinical entity that should be kept in mind of the neurotologist when approaching BPPV patients. It is important to distinguish it from recurrence when delayed and from manoeuvre failure when immediate. The timing of manoeuvre performing, in particular the final verification test after therapeutic sessions, is important to prevent the immediate reflux of particles into canals.

  2. An activation-repolarization time metric to predict localized regions of high susceptibility to re-entry

    PubMed Central

    Child, Nicholas; Bishop, Martin J.; Hanson, Ben; Coronel, Ruben; Opthof, Tobias; Bourkens, Bastiaan; Walton, Richard; Efimov, Igor; Bostock, Julian; Hill, Yolanda; Rinaldi, Christopher A; Razavi, Reza; Gill, Jaswinder; Taggart, Peter

    2015-01-01

    Background Initiation of re-entrant ventricular tachycardia (VT) involves complex interactions between activation and repolarization wavefronts. Recent experimental work has identified the time interval between S2 repolarization proximal to a line of functional block and the activation at the adjacent distal side, as a critical determinant of re-entry. Objective We hypothesized: (1) an algorithm could be developed which would generate a spatial map of this interval (designated the “re-entry vulnerability index”-RVI); (2) that this would accurately identify a pathway of re-entry as well as rotor formation in animal experiments and in a computational model; and, (3) that it would be possible to generate an RVI map in humans during routine clinical procedures and co-register with anatomical and electrophysiological features. Methods and Results An algorithm was developed which sampled all points on a multielectrode grid and calculated RVI between all pairs of electrodes within a given radius. The algorithm successfully identified the spatial region with increased susceptibility to re-entry in an established Langendorff pig heart model and the site of re-entry and rotor formation in an optically mapped sheep heart model and corresponding computational simulations. The feasibility of RVI mapping was evaluated during a clinical procedure by co-registering with the anatomy and physiology in a patient undergoing a VT ablation. Conclusions We developed an algorithm to calculate a re-entry vulnerability index from intervals between local repolarization and activation times at all adjacent points over a multielectrode grid. The algorithm accurately identified the region of re-entry in two animal models of functional re-entry. The possibility of clinical application was demonstrated in a patient with VT. PMID:25863160

  3. Design and Calibration of a Flush Air Data System (FADS) for Prediction of the Atmospheric Properties During Re-Entry

    DTIC Science & Technology

    2013-01-01

    during re- entry Professor Olivier P. Chazot Von Karman Institute for Fluid Dynamics (VKI) 72 Chaussee de Waterloo Rhode-Saint-Genese... entry 5a. CONTRACT NUMBER FA8655-11-1-3079 5b. GRANT NUMBER Grant 11-3079 5c. PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Professor...no prior knowledge. 15. SUBJECT TERMS EOARD, Instrumentation, Hypersonics, FADS, Flush Air Data System, Atmospheric Re- entry

  4. First-Order Simulation of Strewn Debris Fields Accompanying Exoatmospheric Re-entry Vehicle Fragmentation by Hypervelocity Impact

    DTIC Science & Technology

    1994-09-01

    1961). 21. Passey, Quinn R., H.J. Melosh , Effects of Atmospheric Breakup on Crater Field Formation, Icarus 42, 211-253 (1980). 22. CRC Handbook...ORDER SIMULATION OF STREWN DEBRIS FIELDS ACCO:MPANYING EXOATMOSPHERIC RE-ENTRY VEillCLE FRAGMENTATION BY HYPERVELOCITY IMPACT by Dr. Gregory W...STREWN DEBRIS FIELDS ACCOMPANYING EXOATMOSPHERIC RE-ENTRY VEHICLE FRAGMENTATION BY HYPERVELOCITY IMPACT by Dr. Gregory W. Frank Recommended By

  5. Ablation of multi-wavelet re-entry: general principles and in silico analyses.

    PubMed

    Spector, Peter S; Correa de Sa, Daniel D; Tischler, Ethan S; Thompson, Nathaniel C; Habel, Nicole; Stinnett-Donnelly, Justin; Benson, Bryce E; Bielau, Philipp; Bates, Jason H T

    2012-11-01

    Catheter ablation strategies for treatment of cardiac arrhythmias are quite successful when targeting spatially constrained substrates. Complex, dynamic, and spatially varying substrates, however, pose a significant challenge for ablation, which delivers spatially fixed lesions. We describe tissue excitation using concepts of surface topology which provides a framework for addressing this challenge. The aim of this study was to test the efficacy of mechanism-based ablation strategies in the setting of complex dynamic substrates. We used a computational model of propagation through electrically excitable tissue to test the effects of ablation on excitation patterns of progressively greater complexity, from fixed rotors to multi-wavelet re-entry. Our results indicate that (i) focal ablation at a spiral-wave core does not result in termination; (ii) termination requires linear lesions from the tissue edge to the spiral-wave core; (iii) meandering spiral-waves terminate upon collision with a boundary (linear lesion or tissue edge); (iv) the probability of terminating multi-wavelet re-entry is proportional to the ratio of total boundary length to tissue area; (v) the efficacy of linear lesions varies directly with the regional density of spiral-waves. We establish a theoretical framework for re-entrant arrhythmias that explains the requirements for their successful treatment. We demonstrate the inadequacy of focal ablation for spatially fixed spiral-waves. Mechanistically guided principles for ablating multi-wavelet re-entry are provided. The potential to capitalize upon regional heterogeneity of spiral-wave density for improved ablation efficacy is described.

  6. Flow Redistribution Between Legs and Brain During STS 93 Re-Entry and Landing

    NASA Technical Reports Server (NTRS)

    Arbeille, P.; Meck, J.; Porcher, M.; Benavides, E.; Martin, D. S.; South, D. A.; Ribeiro, C.; Westover, A.

    2003-01-01

    The objective was to quantify bit by bit the arterial hemodynamic response to the successive acceleration induced fluid shifts during re-entry and landing. Method: The astronaut instrumented himself with a flat Doppler probe fixed on the skin, a blood pressure arm cuff, and 3 ECG electrodes. The ICMS (integrated cardiovascular monitoring system, 15x15x25 cu cm, battery powered) designed to monitor Blood pressure, ECG, cerebral and femoral flows was fixed below the astronaut sit in the middeck. Recordings started 5 minutes before de-orbiting (TIG) and stopped 5 min after wheels stop. Results. During re-entry blood pressure increased by 20% at TIG, and then by 25 to 30% during the highest Gz accelerations (approx 1 S g ) . The cerebral flow remained decreased by 10 to 15% below inflight value all during the Entry and landing phases. Conversely the femoral flow increased at TIG and entry ( + l0 to 20%), recovered at 0.lg, and then decreased in proportion with the Gz acceleration (-10% to -40% from 0.5g to 1.5g). The reduction in Femoral flow was associated with an opposite variation in lower limb vascular resistance. Consequently the cerebral flow/femoral flow ratio decreased at TIG and entry (-20%), and then increased according to the Gz acceleration level ( + l0 to +40% from 0.5 to 1.5g). Conclusion: During orthostatic tests (Stand LBNP tests) the cerebral to femoral flow ratio allowed to quantify the efficiency of the flow redistribution between these 2 areas and predicted orthostatic intolerance. In the present case the astronaut was found orthostatically tolerant at postflight tilt tests, but we suggest that during re-entry this parameter could predict the occurrence of syncope in severely disadapted astronauts.

  7. Flow Redistribution Between Legs and Brain During STS 93 Re-Entry and Landing

    NASA Technical Reports Server (NTRS)

    Arbeille, P.; Meck, J.; Porcher, M.; Benavides, E.; Martin, D. S.; South, D. A.; Ribeiro, C.; Westover, A.

    2003-01-01

    The objective was to quantify bit by bit the arterial hemodynamic response to the successive acceleration induced fluid shifts during re-entry and landing. Method: The astronaut instrumented himself with a flat Doppler probe fixed on the skin, a blood pressure arm cuff, and 3 ECG electrodes. The ICMS (integrated cardiovascular monitoring system, 15x15x25 cu cm, battery powered) designed to monitor Blood pressure, ECG, cerebral and femoral flows was fixed below the astronaut sit in the middeck. Recordings started 5 minutes before de-orbiting (TIG) and stopped 5 min after wheels stop. Results. During re-entry blood pressure increased by 20% at TIG, and then by 25 to 30% during the highest Gz accelerations (approx 1 S g ) . The cerebral flow remained decreased by 10 to 15% below inflight value all during the Entry and landing phases. Conversely the femoral flow increased at TIG and entry ( + l0 to 20%), recovered at 0.lg, and then decreased in proportion with the Gz acceleration (-10% to -40% from 0.5g to 1.5g). The reduction in Femoral flow was associated with an opposite variation in lower limb vascular resistance. Consequently the cerebral flow/femoral flow ratio decreased at TIG and entry (-20%), and then increased according to the Gz acceleration level ( + l0 to +40% from 0.5 to 1.5g). Conclusion: During orthostatic tests (Stand LBNP tests) the cerebral to femoral flow ratio allowed to quantify the efficiency of the flow redistribution between these 2 areas and predicted orthostatic intolerance. In the present case the astronaut was found orthostatically tolerant at postflight tilt tests, but we suggest that during re-entry this parameter could predict the occurrence of syncope in severely disadapted astronauts.

  8. Re-entry devices in the treatment of peripheral chronic occlusions.

    PubMed

    Smith, Marcus; Pappy, Reji; Hennebry, Thomas A

    2011-01-01

    Chronic occlusions are present in up to 40% of patients who undergo treatment for symptomatic peripheral arterial disease. The primary difficulty encountered during the treatment of chronic occlusions is inability to re-enter the true lumen after subintimal crossing of the occlusion. Two devices have been designed to mitigate this limitation via controlled re-entry. Herein, we report our experience with the Outback LTD catheter and the Pioneer Plus Catheter PPlus 120 in re-entering the true arterial lumen during percutaneous intentional extraluminal revascularization for peripheral chronic occlusions involving the superficial femoral artery. In reviewing our peripheral interventions performed from February 2006 through February 2009, we evaluated angiograms, patients' characteristics, presentations, types of lesions, procedural successes, complications, and symptom-free intervals. The total study population consisted of 23 patients. The Outback catheter was used in 15 patients and the Pioneer catheter in 8 patients.The procedure was successful in all 8 Pioneer cases (100%) and in 13 of the 15 Outback cases (87%). All 8 (100%) of the patients in the Pioneer group and 12 of the 14 patients in the Outback group (86%) remained asymptomatic at an average of 12 months. Overall, there were no procedural complications, amputations, or deaths. This single-center experience demonstrates that the Outback and Pioneer re-entry catheters are safe and effective in managing peripheral chronic occlusions, with an average symptom-free interval of 12 months. This management strategy proves to be reasonable when standard techniques fail to achieve true lumen re-entry.

  9. Re-Entry Devices in the Treatment of Peripheral Chronic Occlusions

    PubMed Central

    Smith, Marcus; Pappy, Reji; Hennebry, Thomas A.

    2011-01-01

    Chronic occlusions are present in up to 40% of patients who undergo treatment for symptomatic peripheral arterial disease. The primary difficulty encountered during the treatment of chronic occlusions is inability to re-enter the true lumen after subintimal crossing of the occlusion. Two devices have been designed to mitigate this limitation via controlled re-entry. Herein, we report our experience with the Outback LTD catheter and the Pioneer Plus Catheter PPlus 120 in re-entering the true arterial lumen during percutaneous intentional extraluminal revascularization for peripheral chronic occlusions involving the superficial femoral artery. In reviewing our peripheral interventions performed from February 2006 through February 2009, we evaluated angiograms, patients' characteristics, presentations, types of lesions, procedural successes, complications, and symptom-free intervals. The total study population consisted of 23 patients. The Outback catheter was used in 15 patients and the Pioneer catheter in 8 patients. The procedure was successful in all 8 Pioneer cases (100%) and in 13 of the 15 Outback cases (87%). All 8 (100%) of the patients in the Pioneer group and 12 of the 14 patients in the Outback group (86%) remained asymptomatic at an average of 12 months. Overall, there were no procedural complications, amputations, or deaths. This single-center experience demonstrates that the Outback and Pioneer re-entry catheters are safe and effective in managing peripheral chronic occlusions, with an average symptom-free interval of 12 months. This management strategy proves to be reasonable when standard techniques fail to achieve true lumen re-entry. PMID:21841867

  10. Sensor Fusion of Gaussian Mixtures for Ballistic Target Tracking in the Re-Entry Phase

    PubMed Central

    Lu, Kelin; Zhou, Rui

    2016-01-01

    A sensor fusion methodology for the Gaussian mixtures model is proposed for ballistic target tracking with unknown ballistic coefficients. To improve the estimation accuracy, a track-to-track fusion architecture is proposed to fuse tracks provided by the local interacting multiple model filters. During the fusion process, the duplicate information is removed by considering the first order redundant information between the local tracks. With extensive simulations, we show that the proposed algorithm improves the tracking accuracy in ballistic target tracking in the re-entry phase applications. PMID:27537883

  11. Re-entry simulation chamber for thermo-mechanical characterisation of space materials

    NASA Astrophysics Data System (ADS)

    Liedtke, Volker

    2003-09-01

    During re-entry, materials and components are subject to very high thermal and mechanical loads. Any failure may cause loss of mission. Therefore, materials and components have to be tested under most rigid conditions to verify the suitability of the material and to verify the design of the components. The Re-Entry Simulation Chamber (RESiC) at ARC Seibersdorf research (ARCS) allows simulating the high thermal loads as well as complex mechanical load profiles that may occur during a re-entry; additionally, the influence of chemical reactions of materials with gaseous components of the atmosphere can be studied. The high vacuum chamber (better than 1×10-6 mbar) has a diameter of 650 mm and allows a sample height of 500 mm, or 1000 mm with extension flange. The gas dosing system is designed to emulate the increasing atmospheric pressure during the re-entry trajectory of a vehicle. Heating is performed by a 30 kW induction generator that allows a sufficiently rapid heating of larger components; electrically conductive materials such as metals or carbon fibre reinforced ceramics are directly heated, while for electrical insulators, susceptor plates or tubes will be employed. The uniaxial servo-hydraulic testing machine has a maximum load of 70 kN, either static or with a frequency of up to 70 Hz, with any given load profile (sinus, rectangular, triangular, ...). Strain measurements will be done by non-contacting laser speckle system for maximum flexibility and minimum instrumentation time effort (currently under application testing), or by strain gauges. All relevant process parameters are controlled and recorded by microcomputer. The highly sophisticated control software allows a convenient and reliable multi-channel data acquisition, e.g. temperatures at various positions of the test piece, pressure, loads, strains, and any other test data according to customer specifications; the data format is suitable for any further data processing. During the set-up and

  12. Sensor Fusion of Gaussian Mixtures for Ballistic Target Tracking in the Re-Entry Phase.

    PubMed

    Lu, Kelin; Zhou, Rui

    2016-08-15

    A sensor fusion methodology for the Gaussian mixtures model is proposed for ballistic target tracking with unknown ballistic coefficients. To improve the estimation accuracy, a track-to-track fusion architecture is proposed to fuse tracks provided by the local interacting multiple model filters. During the fusion process, the duplicate information is removed by considering the first order redundant information between the local tracks. With extensive simulations, we show that the proposed algorithm improves the tracking accuracy in ballistic target tracking in the re-entry phase applications.

  13. Thermal Analysis of the X-38 Aft Fin During Re-Entry

    NASA Technical Reports Server (NTRS)

    Hong, Andrew E.

    1999-01-01

    This document contains the details of the thermal analysis of the X-38 aft fin during re-entry. This analysis was performed in order to calculate temperature response of the aft fin components. This would be provided as input to a structural analysis and would also define the operating environment for the electromechanical actuator (EMA). The calculated structural temperature response would verify the performance of the thermal protection system (TPS). The geometric representation of the aft fin was derived from an I-DEAS finite element model that was used for structural analysis. The thermal mass network model was derived from the geometric representation.

  14. Optimal control approach to termination of re-entry waves in cardiac electrophysiology

    PubMed Central

    Nagaiah, Chamakuri; Kunisch, Karl; Plank, Gernot

    2014-01-01

    This work proposes an optimal control approach for the termination of re-entry waves in cardiac electrophysiology. The control enters as an extracellular current density into the bidomain equations which are well established model equations in the literature to describe the electrical behavior of the cardiac tissue. The optimal control formulation is inspired, in part, by the dynamical systems behavior of the underlying system of differential equations. Existence of optimal controls is established and the optimality system is derived formally. The numerical realization is described in detail and numerical experiments, which demonstrate the capability of influencing and terminating reentry phenomena, are presented. PMID:22684847

  15. Thermographic Imaging of the Space Shuttle During Re-Entry Using a Near Infrared Sensor

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Horvath, Thomas J.; Kerns, Robbie V.; Burke, Eric R.; Taylor, Jeff C.; Spisz, Tom; Gibson, David M.; Shea, Edward J.; Mercer, C. David; Schwartz, Richard J.; Tack, Steve; Bush, Brett C.; Dantowitz, Ronald F.; Kozubal, Marek J.

    2012-01-01

    High resolution calibrated near infrared (NIR) imagery of the Space Shuttle Orbiter was obtained during hypervelocity atmospheric re-entry of the STS-119, STS-125, STS-128, STS-131, STS-132, STS-133, and STS-134 missions. This data has provided information on the distribution of surface temperature and the state of the airflow over the windward surface of the Orbiter during descent. The thermal imagery complemented data collected with onboard surface thermocouple instrumentation. The spatially resolved global thermal measurements made during the Orbiter s hypersonic re-entry will provide critical flight data for reducing the uncertainty associated with present day ground-to-flight extrapolation techniques and current state-of-the-art empirical boundary-layer transition or turbulent heating prediction methods. Laminar and turbulent flight data is critical for the validation of physics-based, semi-empirical boundary-layer transition prediction methods as well as stimulating the validation of laminar numerical chemistry models and the development of turbulence models supporting NASA s next-generation spacecraft. In this paper we provide details of the NIR imaging system used on both air and land-based imaging assets. The paper will discuss calibrations performed on the NIR imaging systems that permitted conversion of captured radiant intensity (counts) to temperature values. Image processing techniques are presented to analyze the NIR data for vignetting distortion, best resolution, and image sharpness. Keywords: HYTHIRM, Space Shuttle thermography, hypersonic imaging, near infrared imaging, histogram analysis, singular value decomposition, eigenvalue image sharpness

  16. Casualty Risk Assessment Controlled Re-Entry of EPS - Ariane 5ES - ATV Mission

    NASA Astrophysics Data System (ADS)

    Arnal, M.-H.; Laine, N.; Aussilhou, C.

    2012-01-01

    To fulfil its mission of compliance check to the French Space Operations Act, CNES has developed ELECTRA© tool in order to estimate casualty risk induced by a space activity (like rocket launch, controlled or un-controlled re-entry on Earth of a space object). This article describes the application of such a tool for the EPS controlled re-entry during the second Ariane 5E/S flight (Johannes Kepler mission has been launched in February 2011). EPS is the Ariane 5E/S upper composite which is de-orbited from a 260 km circular orbit after its main mission (release of the Automated Transfer Vehicle - ATV). After a brief description of the launcher, the ATV-mission and a description of all the failure cases taken into account in the mission design (which leads to "back-up scenarios" into the flight software program), the article will describe the steps which lead to the casualty risk assessment (in case of failure) with ELECTRA©. In particular, the presence on board of two propulsive means of de-orbiting (main engine of EPS, and 4 ACS longitudinal nozzles in case of main engine failure or exhaustion) leads to a low remaining casualty risk.

  17. Near-Optimal Re-Entry Trajectories for Reusable Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Chou, H.-C.; Ardema, M. D.; Bowles, J. V.

    1997-01-01

    A near-optimal guidance law for the descent trajectory for earth orbit re-entry of a fully reusable single-stage-to-orbit pure rocket launch vehicle is derived. A methodology is developed to investigate using both bank angle and altitude as control variables and selecting parameters that maximize various performance functions. The method is based on the energy-state model of the aircraft equations of motion. The major task of this paper is to obtain optimal re-entry trajectories under a variety of performance goals: minimum time, minimum surface temperature, minimum heating, and maximum heading change; four classes of trajectories were investigated: no banking, optimal left turn banking, optimal right turn banking, and optimal bank chattering. The cost function is in general a weighted sum of all performance goals. In particular, the trade-off between minimizing heat load into the vehicle and maximizing cross range distance is investigated. The results show that the optimization methodology can be used to derive a wide variety of near-optimal trajectories.

  18. Collisional-radiative model in air for earth re-entry problems

    SciTech Connect

    Bultel, Arnaud; Cheron, Bruno G.; Bourdon, Anne; Motapon, Ousmanou; Schneider, Ioan F.

    2006-04-15

    A nonlinear time-dependent two-temperature collisional-radiative model for air plasma has been developed for pressures between 1 kPa and atmospheric pressure to be applied to the flow conditions of space vehicle re-entry into the Earth's atmosphere. The model consists of 13 species: N{sub 2}, O{sub 2}, N, O, NO, N{sub 2}{sup +}, O{sub 2}{sup +}, N{sup +}, O{sup +}, NO{sup +}, O{sub 2}{sup -}, O{sup -} in their ground state and major electronic excited states and of electrons. Many elementary processes are considered given the temperatures involved (up to 10 000 K). Time scales to reach the final nonequilibrium or equilibrium steady states are derived. Then we apply our model to two typical re-entry situations and show that O{sub 2}{sup -} and O{sup -} play an important role during the ionization phase. Finally, a comparison with existing reduced kinetic mechanisms puts forward significant discrepancies for high velocity flows when the flow is in chemical nonequilibrium and smaller discrepancies when the flow is close to chemical equilibrium. This comparison illustrates the interest of using a time-dependent collisional-radiative model to validate reduced kinetic schemes for the relevant time scales of the flows studied.

  19. SHEFEX II - Aerodynamic Re-Entry Controlled Sharp Edge Flight Experiment

    NASA Astrophysics Data System (ADS)

    Longo, J. M. A.; Turner, J.; Weihs, H.

    2009-01-01

    In this paper the basic goals and architecture of the SHEFEX II mission is presented. Also launched by a two staged sounding rocket system SHEFEX II is a consequent next step in technology test and demonstration. Considering all experience and collected flight data obtained during the SHEFEX I Mission, the test vehicle has been re-designed and extended by an active control system, which allows active aerodynamic control during the re-entry phase. Thus, ceramic based aerodynamic control elements like rudders, ailerons and flaps, mechanical actuators and an automatic electronic control unit has been implemented. Special focus is taken on improved GNC Elements. In addition, some other experiments including an actively cooled thermal protection element, advanced sensor equipment, high temperature antenna inserts etc. are part of the SHEFEX II experimental payload. A final 2 stage configuration has been selected considering Brazilian solid rocket boosters derived from the S 40 family. During the experiment phase a maximum entry velocity of Mach around 10 is expected for 50 seconds. Considering these flight conditions, the heat loads are not representative for a RLV re-entry, however, it allows to investigate the principal behaviour of such a facetted ceramic TPS, a sharp leading edge at the canards and fins and all associated gas flow effects and their structural response.

  20. A Study on Earth Re-entry Capsules with Deployable Aerobrakes for Recoverable Microgravity Experiments

    NASA Astrophysics Data System (ADS)

    Carandente, Valerio; Savino, Raffaele; D'Oriano, Vera; Fortezza, Raimondo

    2015-06-01

    Deployable aerobrakes for Earth re-entry capsules may offer many advantages in the near future, including the opportunity to recover on Earth scientific payloads from the Space with reduced risks and costs with respect to conventional systems. Such capsules can be accommodated in the selected launcher in folded configuration optimizing the available volume and, when planned by the mission profile, the aerobrake can be deployed in order to increase the surface exposed to the hypersonic flow and therefore to reduce the ballistic parameter. This can offer as main advantage the opportunity to perform an aerodynamic de-orbit of the system without the need of a dedicated propulsive subsystem and an atmospheric re-entry with reduced aerothermal and mechanical loads making possible the use of relatively lightweight and cheap thermal protection system materials. To ensure the recovery of the capsule, the deployable surface can be modulated to obtain the aerodynamic control of the de-orbit trajectory in order to correctly target the capsule towards the selected landing site for post-flight analyses and operations. The main objective of the work is to present a number of feasible mission profiles for orbital platforms to/from Low Earth Orbit aimed in particular at scientific experiments in microgravity conditions. In addition, a suborbital scenario for a technological demonstrator, useful to experimentally verify the system applicability before the design of orbital missions, is also presented and discussed.

  1. Structural Analysis and Testing of the Inflatable Re-entry Vehicle Experiment (IRVE)

    NASA Technical Reports Server (NTRS)

    Lindell, Michael C.; Hughes, Stephen J.; Dixon, Megan; Wiley, Cliff E.

    2006-01-01

    The Inflatable Re-entry Vehicle Experiment (IRVE) is a 3.0 meter, 60 degree half-angle sphere cone, inflatable aeroshell experiment designed to demonstrate various aspects of inflatable technology during Earth re-entry. IRVE will be launched on a Terrier-Improved Orion sounding rocket from NASA s Wallops Flight Facility in the fall of 2006 to an altitude of approximately 164 kilometers and re-enter the Earth s atmosphere. The experiment will demonstrate exo-atmospheric inflation, inflatable structure leak performance throughout the flight regime, structural integrity under aerodynamic pressure and associated deceleration loads, thermal protection system performance, and aerodynamic stability. Structural integrity and dynamic response of the inflatable will be monitored with photogrammetric measurements of the leeward side of the aeroshell during flight. Aerodynamic stability and drag performance will be verified with on-board inertial measurements and radar tracking from multiple ground radar stations. In addition to demonstrating inflatable technology, IRVE will help validate structural, aerothermal, and trajectory modeling and analysis techniques for the inflatable aeroshell system. This paper discusses the structural analysis and testing of the IRVE inflatable structure. Equations are presented for calculating fabric loads in sphere cone aeroshells, and finite element results are presented which validate the equations. Fabric material properties and testing are discussed along with aeroshell fabrication techniques. Stiffness and dynamics tests conducted on a small-scale development unit and a full-scale prototype unit are presented along with correlated finite element models to predict the in-flight fundamental mod

  2. VEGA 4th Stage Direct Re-Entry Survivability Analysis and Casualty Risk Assessment

    NASA Astrophysics Data System (ADS)

    Battie, F.; Fossati, T.; Gallucci, S.

    2013-08-01

    A key task in launch vehicle (LV) system design process consists in the estimation of upper stage fragmentation during atmospheric re-entry once accomplished the launcher mission, and the related probability of making on-ground casualties. As a European launcher operating from French Guyana, VEGA has to abide by ESA debris mitigation rules, and by the French Law on Space Operations (LOS). The second flight of VEGA aims at demonstrating the versatility of the launcher by performing a multi-payload launch with different target orbits. From a safety point of view, the compliance of VEGA to the LOS will also be extended through the performance of the direct deorbiting of its upper stage, the AVUM, at the end of its mission. Indeed, during the qualification flight, VEGA had submitted to the safety authorities the derogation envisaged by the LOS: under certain conditions, it allows the indirect re-entry of the launcher's upper stage, provided it shall do so in less than 25 years.

  3. Vulnerability to re-entry in simulated two-dimensional cardiac tissue: Effects of electrical restitution and stimulation sequence

    NASA Astrophysics Data System (ADS)

    Tran, Diana X.; Yang, Ming-Jim; Weiss, James N.; Garfinkel, Alan; Qu, Zhilin

    2007-12-01

    Ventricular fibrillation is a lethal arrhythmia characterized by multiple wavelets usually starting from a single or figure-of-eight re-entrant circuit. Understanding the factors regulating vulnerability to the re-entry is essential for developing effective therapeutic strategies to prevent ventricular fibrillation. In this study, we investigated how pre-existing tissue heterogeneities and electrical restitution properties affect the initiation of re-entry by premature extrastimuli in two-dimensional cardiac tissue models. We studied two pacing protocols for inducing re-entry following the "sinus" rhythm (S1) beat: (1) a single premature (S2) extrastimulus in heterogeneous tissue; (2) two premature extrastimuli (S2 and S3) in homogeneous tissue. In the first case, the vulnerable window of re-entry is determined by the spatial dimension and extent of the heterogeneity, and is also affected by electrical restitution properties and the location of the premature stimulus. The vulnerable window first increases as the action potential duration (APD) difference between the inside and outside of the heterogeneous region increases, but then decreases as this difference increases further. Steeper APD restitution reduces the vulnerable window of re-entry. In the second case, electrical restitution plays an essential role. When APD restitution is flat, no re-entry can be induced. When APD restitution is steep, re-entry can be induced by an S3 over a range of S1S2 intervals, which is also affected by conduction velocity restitution. When APD restitution is even steeper, the vulnerable window is reduced due to collision of the spiral tips.

  4. Simulation of launch and re-entry acceleration profiles for testing of shuttle and unmanned microgravity research payloads

    NASA Astrophysics Data System (ADS)

    Cassanto, J. M.; Ziserman, H. I.; Chapman, D. K.; Korszun, Z. R.; Todd, P.

    Microgravity experiments designed for execution in Get-Away Special canisters, Hitchhiker modules, and Reusable Re-entry Satellites will be subjected to launch and re-entry accelerations. Crew-dependent provisions for preventing acceleration damage to equipment or products will not be available for these payloads during flight; therefore, the effects of launch and re-entry accelerations on all aspects of such payloads must be evaluated prior to flight. A procedure was developed for conveniently simulating the launch and re-entry acceleration profiles of the Space Shuttle (3.3 and 1.7 × g maximum, respectively) and of two versions of NASA's proposed materials research Re-usable Re-entry Satellite (8 × g maximum in one case and 4 × g in the other). By using the 7 m centrifuge of the Gravitational Plant Physiology Laboratory in Philadelphia it was found possible to simulate the time dependence of these 5 different acceleration episodes for payload masses up to 59 kg. A commercial low-cost payload device, the “Materials Dispersion Apparatus” of Instrumentation Technology Associates was tested for (1) integrity of mechanical function, (2) retention of fluid in its compartments, and (3) integrity of products under simulated re-entry g-loads. In particular, the sharp rise from 1 g to maximum g-loading that occurs during re-entry in various unmanned vehicles was successfully simulated, conditions were established for reliable functioning of the MDA, and crystals of 5 proteins suspended in compartments filled with mother liquor were subjected to this acceleration load.

  5. Vulnerability to re-entry in simulated two-dimensional cardiac tissue: effects of electrical restitution and stimulation sequence.

    PubMed

    Tran, Diana X; Yang, Ming-Jim; Weiss, James N; Garfinkel, Alan; Qu, Zhilin

    2007-12-01

    Ventricular fibrillation is a lethal arrhythmia characterized by multiple wavelets usually starting from a single or figure-of-eight re-entrant circuit. Understanding the factors regulating vulnerability to the re-entry is essential for developing effective therapeutic strategies to prevent ventricular fibrillation. In this study, we investigated how pre-existing tissue heterogeneities and electrical restitution properties affect the initiation of re-entry by premature extrastimuli in two-dimensional cardiac tissue models. We studied two pacing protocols for inducing re-entry following the "sinus" rhythm (S1) beat: (1) a single premature (S2) extrastimulus in heterogeneous tissue; (2) two premature extrastimuli (S2 and S3) in homogeneous tissue. In the first case, the vulnerable window of re-entry is determined by the spatial dimension and extent of the heterogeneity, and is also affected by electrical restitution properties and the location of the premature stimulus. The vulnerable window first increases as the action potential duration (APD) difference between the inside and outside of the heterogeneous region increases, but then decreases as this difference increases further. Steeper APD restitution reduces the vulnerable window of re-entry. In the second case, electrical restitution plays an essential role. When APD restitution is flat, no re-entry can be induced. When APD restitution is steep, re-entry can be induced by an S3 over a range of S1S2 intervals, which is also affected by conduction velocity restitution. When APD restitution is even steeper, the vulnerable window is reduced due to collision of the spiral tips.

  6. Simulation of launch and re-entry acceleration profiles for testing of shuttle and unmanned microgravity research payloads.

    PubMed

    Cassanto, J M; Ziserman, H I; Chapman, D K; Korszun, Z R; Todd, P

    1988-01-01

    Microgravity experiments designed for execution in Get-Away Special canisters, Hitchhiker modules, and Reusable Re-entry Satellites will be subjected to launch and re-entry accelerations. Crew-dependent provisions for preventing acceleration damage to equipment or products will not be available for these payloads during flight; therefore, the effects of launch and re-entry accelerations on all aspects of such payloads must be evaluated prior to flight. A procedure was developed for conveniently simulating the launch and re-entry acceleration profiles of the Space Shuttle (3.3 and 1.7 x g maximum, respectively) and of two versions of NASA's proposed materials research Re-usable Re-entry Satellite (8 x g maximum in one case and 4 x g in the other). By using the 7 m centrifuge of the Gravitational Plant Physiology Laboratory in Philadelphia it was found possible to simulate the time dependence of these 5 different acceleration episodes for payload masses up to 59 kg. A commercial low-cost payload device, the "Materials Dispersion Apparatus" of Instrumentation Technology Associates was tested for (1) integrity of mechanical function, (2) retention of fluid in its compartments, and (3) integrity of products under simulated re-entry g-loads. In particular, the sharp rise from 1 g to maximum g-loading that occurs during re-entry in various unmanned vehicles was successfully simulated, conditions were established for reliable functioning of the MDA, and crystals of 5 proteins suspended in compartments filled with mother liquor were subjected to this acceleration load.

  7. Dynamic and Static High Temperature Resistant Ceramic Seals for X- 38 re-Entry Vehicle

    NASA Astrophysics Data System (ADS)

    Handrick, Karin E.; Curry, Donald M.

    2002-01-01

    In a highly successful partnership, NAS A, ESA, DLR (German Space Agency) and European industry are building the X-38, V201 re-entry spacecraft, the prototype of the International Space Station's Crew Return Vehicle (CRV). This vehicle would serve both as an ambulance for medical emergencies and as an evacuation vehicle for the Space Station. The development of essential systems and technologies for a reusable re-entry vehicle is a first for Europe, and sharing the development of an advanced re-entry spacecraft with foreign partners is a first for NASA. NASA, in addition to its subsystem responsibilities, is performing overall X-38 vehicle system engineering and integration, will launch V201 on the Space Shuttle, deliver flight data for post-flight analysis and assessment and is responsible for development and manufacture of structural vehicle components and thermal protection (TPS) tiles. The major European objective for cooperation with NASA on X-38 was to establish a clear path through which key technologies needed for future space transportation systems could be developed and validated at affordable cost and with controlled risk. Europe has taken the responsibility to design and manufacture hot control surfaces like metallic rudders and ceramic matrix composites (CMC) body flaps, thermal protection systems such as CMC leading edges, the CMC nose cap and -skirt, insulation, landing gears and elements of the V201 primary structure. Especially hot control surfaces require extremely high temperature resistant seals to limit hot gas ingestion and transfer of heat to underlying low-temperature structures to prevent overheating of these structures and possible loss of the vehicle. Complex seal interfaces, which have to fulfill various, tight mission- and vehicle-related requirements exist between the moveable ceramic body flaps and the bottom surface of the vehicle, between the rudder and fin structure and the ceramic leading edge panel and TPS tiles. While NASA

  8. Initiation of re-entry in an excitable medium: Structural investigation of cardiac tissue using a genetic algorithm

    NASA Astrophysics Data System (ADS)

    Scarle, S.; Clayton, R. H.

    2006-09-01

    The detailed mechanisms by which re-entry and ventricular fibrillation are initiated in the heart remain poorly understood because they are difficult to investigate experimentally. We have used a simplified excitable media computational model of action potential propagation to systematically study how re-entry can be produced by diffuse regions of inexcitable tissue. Patterns of excitable and inexcitable tissue were generated using a genetic algorithm. The inexcitable tissue was modeled in two ways: (i) diffusive, electrically connected but inexcitable tissue, or (ii) zero-flux, areas of tissue electrically disconnected in the same way as zero-flux boundary conditions. We were able to evolve patterns of diffuse inexcitable tissue that favored re-entry, but no single structure or pattern emerged. Diffusive inexcitable regions were inherently less arrhythmogenic than zero-flux inexcitable ones.

  9. [The ergonomic aspects of space vehicle manual motion control during re-entry].

    PubMed

    Barer, A S

    2006-01-01

    In 1960s, the Russian space program spared no resources for extensive theoretical and empiric studies of manual control by vehicles during re-entry at the second and first space speeds by cosmonauts experiencing g-loads of up to 18 g. About 6,000 static and 400 centrifuge experiments were performed, and if g-loads caused loss of vision the cosmonaut remained operational getting audible indication. Ergonomic characteristics of the control organs and indicators were high enough to guarantee accuracy despite the g-loads comparable with values under static conditions. The store of knowledge acquired in those studies does not lose significance for the present-day piloted space programs.

  10. European Experimental Re-Entry Testbed EXPERT: Qualification of Payloads for Flight

    NASA Astrophysics Data System (ADS)

    Ratti, F.; Gavira, J.; Thirkettle, A. C.; Erba, F.; Muylaert, J.-M.; Walpot, L.; Rembiasz, J. M.

    2009-01-01

    The European Experimental Re-entry Test-bed EXPERT is developed by the European Space Agency (ESA) as part of its General Technological Research Program (GSTP). The aim of EXPERT is to improve the understanding of critical aero-thermodynamic phenomena associated with hypersonic re-entry flights. The EXPERT project provides an opportunity to the scientific community and industries throughout Europe to propose and perform experiments in order to obtain aero-thermodynamic data for the validation of numerical models and of ground to flight extrapolation methodologies. During the last years an intense activity has been performed at ESA in order to select the most suitable experiments, bring them to a mature design, manufacture the qualification model and qualify the experiments for flight. ESA staffs coordinated and supported the work of the principal investigators of the experiments from European institutions and industrial organizations in order to maximize the scientific output in compliance with the budget resources made available to the EXPERT project and the programmatic constraints. EXPERT is a re-entry capsule having the shape of a blunted cone. The front part consists of a nose made of ceramic material developed at DLR Stuttgart. No ablative material is implemented so as not to contaminate the specific measurements of Payloads on board. The ceramic nose hosts a set of experiments: the Flush Air Data System (FADS) developed by HTG aiming at collecting free flow data required for post flight analysis, the pyrometer PYREX developed at IRS in Stuttgart collecting data on the temperature and heat flux of the ceramic nose, and the IRS spectrometer RESPECT aiming at resolving the different species generated in the plasma region during re-entry. The sides of the blunted cone are protected by a metallic thermal protection system in which several experiments are located. Two Payloads developed by IRS and VKI are dedicated to the measurement of catalytic effects. One aims

  11. Numerical Flight Mechanics Analysis Of The SHEFEX I Ascent And Re-Entry Phases

    NASA Astrophysics Data System (ADS)

    Bartolome Calvo, Javier; Eggers, Thino

    2011-08-01

    The SHarp Edge Flight EXperiment (SHEFEX) I provides a huge amount of scientific data to validate numerical tools in hypersonic flows. These data allow the direct comparison of flight measurements with the current numerical tools available at DLR. Therefore, this paper is devoted to apply a recently developed direct coupling between aerodynamics and flight dynamics to the SHEFEX I flight. In a first step, mission analyses are carried out using the trajectory optimization program REENT 6D coupled to missile DATCOM. In a second step, the direct coupling between the trajectory program and the DLR TAU code, in which the unsteady Euler equations including rigid body motion are solved, is applied to analyze some interesting parts of ascent and re-entry phases of the flight experiment. The agreement of the numerical predictions with the obtained flight data is satisfactory assuming a variable fin deflection angle.

  12. Static mechanical strain induces capillary endothelial cell cycle re-entry and sprouting

    NASA Astrophysics Data System (ADS)

    Zeiger, A. S.; Liu, F. D.; Durham, J. T.; Jagielska, A.; Mahmoodian, R.; Van Vliet, K. J.; Herman, I. M.

    2016-08-01

    Vascular endothelial cells are known to respond to a range of biochemical and time-varying mechanical cues that can promote blood vessel sprouting termed angiogenesis. It is less understood how these cells respond to sustained (i.e., static) mechanical cues such as the deformation generated by other contractile vascular cells, cues which can change with age and disease state. Here we demonstrate that static tensile strain of 10%, consistent with that exerted by contractile microvascular pericytes, can directly and rapidly induce cell cycle re-entry in growth-arrested microvascular endothelial cell monolayers. S-phase entry in response to this strain correlates with absence of nuclear p27, a cyclin-dependent kinase inhibitor. Furthermore, this modest strain promotes sprouting of endothelial cells, suggesting a novel mechanical ‘angiogenic switch’. These findings suggest that static tensile strain can directly stimulate pathological angiogenesis, implying that pericyte absence or death is not necessarily required of endothelial cell re-activation.

  13. Dust particles in high-speed flows: calculations of small-particle re-entry hydrodynamics

    SciTech Connect

    Sandford, M.T. II

    1984-02-01

    Numerical hydrodynamic calculations are used to model the dispersion of dust injected into a supersonic flow by the explosive disruption of a re-entry vehicle. The particles constitute an initial dustball that expands into the existing velocity field after the detonation. Dust grains subsequently form a plume along the vehicle path. The importance of aerodynamic and radiative heating of the dust is considered but not included in the calculations. Particles in the bow shock heat to the vaporization temperature because of drag and radiative heating, but particles in the dustball are shielded and consequently suffer only a small amount of vaporization. About 20% of the initial dust mass will be vaporized. Application of the results to dust grains entrained in the air blast of a near-surface nuclear explosion is briefly considered. 4 references, 6 figures, 1 table.

  14. Characteristics of the GOCE Orbit in the Re-Entry Phase

    NASA Astrophysics Data System (ADS)

    Hamm, Johann; Lengsfeld, Alexander; Kekce, Ugur; Pape, Werner; Shabanloui, Akbar; Naeimi, Majid; Flury, Jakob

    2015-03-01

    The GOCE de-orbiting phase was started as the Ion thruster was switched off on 21st October 2013. Beginning with this, the transition from the Drag-Free and Attitude Control System (DFACS) to Fine Pointing Mode (FPM) started, so the Gradiometer was no longer in the attitude control loop. On 11th of November 2013, the de-orbiting phase ended with the re-entry of GOCE in the Earth’s atmosphere, near to the Falkland Islands. As a part of a research project, we analyzed the 20 days of the GOCE data during de-orbiting phase. We investigate: Electrostatic Gravity Gradiometer (EGG), DFACS Accelerometer data, Magneto-Torques Currents (MTR) data, Precise Science Orbits (PSO) data, Satellite to Satellite Tracking (SST) data and Atmospheric Models (MSISE-90, NRMSISE-00).

  15. Cyclic re-entry of germinal center B cells in dealing with switching antigen

    NASA Astrophysics Data System (ADS)

    He, Chaoyang

    1999-08-01

    Germinal center spatial compartmentalization may help immune cells to optimize their mutation schedule so that affinity maturation through somatic hypermutation achieves higher efficiency. Some pathogens can alter their antigen expression (surface glycoprotein) by evolution of antigen or antigen switching or drifting to counteract the immune defense. We examine the switching antigen situation by introducing a prey-predator model in the string space representation of B cells and antigen, using Pontryagin's maximum principle to seek out the optimal mutation schedule, The optimal mutation schedule is still phase like. We conclude that re-entry of germinal center B cells is still crucial to affinity maturation. We further speculate a model of diffusing B cells coupling with pair correlation function may provide the underlying mechanism for the phasic like mutation schedule.

  16. The Advanced Re-Entry Vehicle (ARV) a Development Step from ATV Toward Manned Transportation Systems

    NASA Astrophysics Data System (ADS)

    Bottacini, M.; Berthe, P.; Vo, X.; Pietsch, K.

    2011-08-01

    The Advanced Re-entry Vehicle (ARV) programme has been undertaken by Europe with the objective to contribute to the preparation of a future European crew transportation system, while providing a valuable logistic support to the ISS through an operational cargo return system. This development would allow: - the early acquisition of critical technologies; - the design, development and testing of elements suitable for the follow up human rated transportation system. These vehicles should also serve future LEO infrastructures and exploration missions. With the aim to satisfy the above objectives a team composed by major European industries and led by EADS Astrium Space Transportation is currently conducting the phase A of the programme under contract with the European Space Agency (ESA). Two vehicle versions are being investigated: a Cargo version, transporting cargo only to/from the ISS, and a Crew version, which will allow the transfer of both crew and cargo to/from the ISS. The ARV Cargo version, in its present configuration, is composed of three modules. The Versatile Service Module (VSM) provides to the system the propulsion/GNC for orbital manoeuvres and attitude control and the orbital power generation. Its propulsion system and GNC shall be robust enough to allow its use for different launch stacks and different LEO missions in the future. The Un-pressurised Cargo Module (UCM) provides the accommodation for about 3000 kg of un-pressurised cargo and is to be sufficiently flexible to ensure the transportation of: - orbital infrastructure components (ORU's); - scientific / technological experiments; - propellant for re-fuelling, re-boost (and deorbiting) of the ISS. The Re-entry Module (RM) provides a pressurized volume to accommodate active/passive cargo (2000 kg upload/1500 kg download). It is conceived as an expendable conical capsule with spherical heat- hield, interfacing with the new docking standard of the ISS, i.e. it carries the IBDM docking system, on a

  17. The Advanced Re-Entry Vehicle (ARV) A Development Step From ATV Toward Manned Transportation Systems

    NASA Astrophysics Data System (ADS)

    Bottacini, Massimiliano; Berthe, Philippe; Vo, Xavier; Pietsch, Klaus

    2011-05-01

    The Advanced Re-entry Vehicle (ARV) programme has been undertaken by Europe with the objective to contribute to the preparation of a future European crew transportation system, while providing a valuable logistic support to the ISS through an operational cargo return system. This development would allow: - the early acquisition of critical technologies; - the design, development and testing of elements suitable for the follow up human rated transportation system. These vehicles should also serve future LEO infrastructures and exploration missions. With the aim to satisfy the above objectives a team composed by major European industries and led by EADS Astrium Space Transportation is currently conducting the phase A of the programme under contract with the European Space Agency (ESA). Two vehicle versions are being investigated: a Cargo version, transporting cargo only to/from the ISS, and a Crew version, which will allow the transfer of both crew and cargo to/from the ISS. The ARV Cargo version, in its present configuration, is composed of three modules. The Versatile Service Module (VSM) provides to the system the propulsion/GNC for orbital manoeuvres and attitude control and the orbital power generation. Its propulsion system and GNC shall be robust enough to allow its use for different launch stacks and different LEO missions in the future. The Un-pressurised Cargo Module (UCM) provides the accommodation for about 3000 kg of unpressurised cargo and is to be sufficiently flexible to ensure the transportation of: - orbital infrastructure components (ORU’s); - scientific / technological experiments; - propellant for re-fuelling, re-boost (and de-orbiting) of the ISS. The Re-entry Module (RM) provides a pressurized volume to accommodate active/passive cargo (2000 kg upload/1500 kg download). It is conceived as an expendable conical capsule with spherical heat-shield, interfacing with the new docking standard of the ISS, i.e. it carries the IBDM docking system, on

  18. Advanced Key Technologies for Hot Control Surfaces in Space Re- Entry Vehicles

    NASA Astrophysics Data System (ADS)

    Dogigli, Michael; Pradier, Alain; Tumino, Giorgio

    2002-01-01

    (1)MAN Technologie AG, D- 86153 Augsburg, Germany (2,3) ESA, 2200 Noordwijk ZH, The Netherlands Current space re-entry vehicles (e.g. X-38 vehicle 201, the prototype of the International Space Station's Crew Return Vehicle (CRV)) require advanced control surfaces (so called body flaps). Such control surfaces allow the design of smaller and lighter vehicles as well as faster re-entries (compared to the US Shuttle). They are designed as light-weight structures that need no metallic parts, need no mass or volume consuming heat sinks to protect critical components (e.g. bearings) and that can be operated at temperatures of more than 1600 "C in air transferring high mechanical loads (dynamic 40 kN, static 70 kN) at the same time. Because there is a need for CRV and also for Reusable Launch Vehicles (RLV) in future, the European Space Agency (ESA) felt compelled to establish a "Future European Space Transportation and Investigation Program,, (FESTIP) and a "General Support for Technology Program,, (GSTP). One of the main goals of these programs was to develop and qualify key-technologies that are able to master the above mentioned challenging requirements for advanced hot control surfaces and that can be applied for different vehicles. In 1996 MAN Technologie has started the development of hot control surfaces for small lifting bodies in the national program "Heiü Strukturen,,. One of the main results of this program was that especially the following CMC (Ceramic Matrix Composite) key technologies need to be brought up to space flight standard: Complex CMC Structures, CMC Bearings, Metal-to-CMC Joining Technologies, CMC Fasteners, Oxidation Protection Systems and Static and Dynamic Seals. MAN Technologie was contracted by ESA to continue the development and qualification of these key technologies in the frame of the FESTIP and the GSTP program. Development and qualification have successfully been carried out. The key technologies have been applied for the X-38 vehicle

  19. Radiative Transfer in Earth Re-entry: Application to the Project Fire II Experiments

    NASA Astrophysics Data System (ADS)

    Lamet, J.-M.; Babou, Y.; Riviere, Ph.; Soufiani, A.; Perrin, M.-Y.

    2006-11-01

    The aim of this paper is to contribute to the test case 6 by computing the radiative heat intensities at the stagnation point for four points of Fire II re-entry trajectory. The prescribed flow-fields provided in the test case booklet are used. The radiative heat flux computations are based on a line by line approach combined with the exhaustive database which has been developed previously [1, 2]. The previous benchmarking of air radiative properties on a LTE air plasma have shown the quality of this database [3]. Since then, the use of this database has been extended to non LTE applications. In addition to the radiation computations defined in test case 6, the spectral distribution of the different intensities is predicted on a wide spectral range from far UV to IR. This will be important for further flow/radiation coupling studies. Different modelling levels are tested: pure emission, absorption effects, and chemical nonequilibrium effects.

  20. The use of inflatable structures for re-entry of orbiting vehicles

    NASA Astrophysics Data System (ADS)

    Kendall, Robert T.; Maddox, Arthur R.

    1990-10-01

    Inflatable recovery systems offer the unique advantage that a large high-drag shape can be stored initially in a relatively small package. The resulting shapes decelerate rapidly with lower heating inputs than other types of re-entry vehicles. Recent developments have led to some light-weight materials, with little thermal protection, can withstand the heating inputs to such vehicles. As a result, inflatable recovery vehicles offer a simple, reliable and economical way to return various vehicles from orbit. This paper examines the application of this concept to a large and a small vehicle with the accompanying dynamics that might be expected. More complex systems could extend the concept to emergency personnel escape systems, payload abort and satellite recovery systems.

  1. Rudder/Fin Seals Investigated for the X-38 Re-Entry Vehicle

    NASA Technical Reports Server (NTRS)

    Dunlap, Patrick H., Jr.; Steinetz, Bruce M.

    2002-01-01

    NASA is developing the X-38 vehicle that will demonstrate the technologies required for a potential crew return vehicle for the International Space Station. This vehicle would serve both as an ambulance for medical emergencies and as an evacuation vehicle for the space station. Control surfaces on the X-38 (body flaps and rudder/fin assemblies) require high temperature seals to limit hot gas ingestion and the transfer of heat to underlying low temperature structures. Working with the NASA Johnson Space Center, the Seals Team at the NASA Glenn Research Center completed a series of tests to further characterize baseline seal designs for the rudder/fin interfaces of the X-38. The structures of the rudder/fin assembly and its associated seals are shown in the the preceding illustration. Tests performed at Glenn indicated that exposure of the seals in a compressed state at simulated seal re-entry temperatures resulted in a large permanent set and loss of seal resiliency. This could be of concern because the seals are required to maintain contact with the sealing surfaces while the vehicle goes through the maximum re-entry heating cycle to prevent hot gases from leaking past the seals and damaging interior low-temperature structures. To simulate conditions in which the seals may become unloaded during use, such as when they take on a large permanent set, Glenn researchers performed room temperature flow and compression tests to determine seal flow rates, resiliency, and unit loads under minimal loads. Flow rates through an unloaded (i.e., 0-percent compression) double seal arrangement were twice those of a double seal compressed to the 20-percent design compression level. These flow rates are being used in thermal analyses to predict the effect of flow through the seals on over-all seal temperatures. Compression test results showed that seal unit loads and contact pressures were below the limits that Johnson had set as goals for the seals. In the rudder/fin seal location

  2. c-MYC is required for germinal center selection and cyclic re-entry

    PubMed Central

    Dominguez-Sola, David; Victora, Gabriel D.; Ying, Carol Y.; Phan, Ryan T.; Saito, Masumichi; Nussenzweig, Michel C.; Dalla-Favera, Riccardo

    2013-01-01

    Upon antigenic challenge, B cells enter the dark-zone (DZ) of germinal-centers (GC) to proliferate and hypermutate their immunoglobulin genes. Mutants with increased affinity are positively selected in the light-zone (LZ) to either differentiate into plasma and memory cells, or re-enter the DZ. The molecular circuits governing GC positive selection are not known. We show that the GC reaction requires the biphasic regulation of c-MYC expression, involving its transient induction during early GC commitment, its repression by BCL6 in DZ B cells, and its re-induction in B cells selected for DZ re-entry. Inhibition of MYC in vivo leads to GC collapse, indicating an essential role in GCs. These results have implications for the mechanism of GC selection and the role of MYC in lymphomagenesis. PMID:23001145

  3. Interaction of the LDEF spacecraft with SRM re-entry firings

    NASA Astrophysics Data System (ADS)

    Stabroth, Sebastian; Flegel, Sven Kevin; Wiedemann, Carsten; Krag, Holger; Klinkrad, Heiner; Vörsmann, Peter

    The ESA space debris population model MASTER (Meteoroid and Space Debris Terrestrial Environment Reference) shows a highly dynamic sub-millimetre size particle environment. The dust population released during firings of solid rocket motors (SRM) in space is a major contributor to the debris flux imposed to orbiting spacecraft. Flux predictions of the current model version MASTER-2005 agree with recent impact data from returned spacecraft surfaces like the Hubble Space Telescope solar arrays orbiting the Earth between 1993 and 2002. However, it was found during validation of MASTER-2005 that the flux level for dust is underpredicted by the model for some of the analysed surfaces of the Long-Duration Exposure Facility (LDEF) in orbit between 1984 and 1990. Since the release of MASTER-2005, it has been recognised that this historical model difference is most likely the result of a large number of Russian SRM retroburns with return capsules not included in the MASTER-2005 event database. The extension of the firing list with the re-entry firings and the re-simulation of the debris environment based on the gathered information closes the gap between measurements and model predictions. In this paper, the identification of previously unknown signatures of the re-entry firings in the impact records of the Interplanetary Dust Experiment (IDE) carried by LDEF will be outlined. The direct confirmation of the simulated firings in the measured data supports the assumptions taken in the database generation and underlines the quality of the particle release models of MASTER. The interaction of LDEF with the simulated particle clouds will be discussed.

  4. FGF10 promotes regional foetal cardiomyocyte proliferation and adult cardiomyocyte cell-cycle re-entry.

    PubMed

    Rochais, Francesca; Sturny, Rachel; Chao, Cho-Ming; Mesbah, Karim; Bennett, Michael; Mohun, Tim J; Bellusci, Saverio; Kelly, Robert G

    2014-12-01

    Cardiomyocyte proliferation gradually declines during embryogenesis resulting in severely limited regenerative capacities in the adult heart. Understanding the developmental processes controlling cardiomyocyte proliferation may thus identify new therapeutic targets to modulate the cell-cycle activity of cardiomyocytes in the adult heart. This study aims to determine the mechanism by which fibroblast growth factor 10 (FGF10) controls foetal cardiomyocyte proliferation and to test the hypothesis that FGF10 promotes the proliferative capacity of adult cardiomyocytes. Analysis of Fgf10(-/-) hearts and primary cardiomyocyte cultures reveals that altered ventricular morphology is associated with impaired proliferation of right but not left-ventricular myocytes. Decreased FOXO3 phosphorylation associated with up-regulated p27(kip) (1) levels was observed specifically in the right ventricle of Fgf10(-/-) hearts. In addition, cell-type-specific expression analysis revealed that Fgf10 and its receptor, Fgfr2b, are expressed in cardiomyocytes and not cardiac fibroblasts, consistent with a cell-type autonomous role of FGF10 in regulating regional specific myocyte proliferation in the foetal heart. Furthermore, we demonstrate that in vivo overexpression of Fgf10 in adult mice promotes cardiomyocyte but not cardiac fibroblast cell-cycle re-entry. FGF10 regulates regional cardiomyocyte proliferation in the foetal heart through a FOXO3/p27(kip1) pathway. In addition, FGF10 triggers cell-cycle re-entry of adult cardiomyocytes and is thus a potential target for cardiac repair. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  5. Numerical prediction of aerothermodynamic effects on a re-entry vehicle body flap configuration

    NASA Astrophysics Data System (ADS)

    Di Clemente, Marco; Marini, Marco; Di Benedetto, Sara; Schettino, Antonio; Ranuzzi, Giuliano

    2009-07-01

    Within the EXPERT program, funded by European Space Agency, a number of experiments to be performed in the CIRA Plasma Wind Tunnel "Scirocco", representative of the capsule flight conditions with respect to the shock wave boundary layer interaction phenomenon occurring around the 20-degree open flap, has been designed: PWT driving conditions, model configuration and attitude and model instrumentation have been defined, by means of a massive CFD activity performed by using the CIRA code H3NS, in order to duplicate on a forebody full-scale flap model both pressure and heat flux levels estimated in critical flight conditions. The model that has been designed reproduces the full scale EXPERT 20-degree flap, mounted on a holder composed by a flat plate with rounded leading and lateral edges; it will be built by using the same materials of EXPERT: i.e. PM1000 for the flat plate and C-SiC for the flap. Detailed 3D computations of the flow around the model with proper thermal and catalytic modeling of the surface have been carried out in the selected test conditions, to duplicate either the SWBLI phenomenon around the body flap either the associated thermo-mechanical loads acting on it during the EXPERT re-entry flight. Predicted results have been compared to test design results and test requirements extracted from the EXPERT re-entry flight. Some physical and geometrical effects (surface catalysis of PM1000 and C-SiC, wall temperature of the model leading edge, base flow) have been studied qualitatively through a series of simpler two-dimensional simulations. It can be concluded that the Test Matrix of the PWT experiments defined in the previous phase of the project is confirmed by the present accurate three-dimensional CFD simulations.

  6. FLPP IXV Re-Entry Vehicle, Supersonic Charectisation Based on DNW SST Wind Tunnel Tests and CFD

    NASA Astrophysics Data System (ADS)

    Kapteijn, C.; Maseland, H.; Chiarelli, C.; Mareschi, V.; Tribot, J.-P.; Binetti, P.; Walloscheck, T.

    2009-01-01

    The European Space Agency ESA, has engaged in 2004, the IXV project (Intermediate eXperimental Vehicle) which is part of the FLPP (Future Launcher Preparatory Programme) aiming at answering to critical technological issues for controlled re-entry, while supporting the future generation launchers and to improve in general European capabilities in the strategic field of atmospheric re-entry for future space transportation, exploration and scientific applications. The IXV key mission and system objectives are the design, development, manufacturing, assembling and on- ground to in-flight verification of an autonomous European lifting and aerodynamically controlled re- entry system, integrating the critical re- entry technologies at the system level. In particular, the IXV shall demonstrate system integrated key technologies such as lifting flight control by means of aerodynamic surfaces that are one of the main primary objectives of the experimental investigation. Lifting and aerodynamic controlled re-entry represents a significant capability advancement with respect to the ballistic re-entry of capsules like the ARD. Since hypersonic aerodynamics is essentially different from supersonic aerodynamics, the current mission is to perform an atmospheric re-entry in combination with a safe recovery the in supersonic flight regime. However, mission extension to trimmed transonic flight is under consideration based on a preliminary analysis of the aerodynamic characteristics of the IXV configuration. Since the beginning of the IXV project, an aerodynamic data base (AEDB) has been built up and continuously updated integrating the additional information mainly provided by means of CFD (ie: Euler and Navier-Stokes) and lately also by means of WTTs. This AEDB serves for flying qualities analysis and for re-entry simulations. During the development phase B2/C1, the effectiveness of the control surfaces and their impact on te vehicle's aerodynamic forces in the supersonic regime is

  7. Development and application of an empirical probability distribution for the prediction error of re-entry body maximum dynamic pressure

    NASA Technical Reports Server (NTRS)

    Lanzi, R. James; Vincent, Brett T.

    1993-01-01

    The relationship between actual and predicted re-entry maximum dynamic pressure is characterized using a probability density function and a cumulative distribution function derived from sounding rocket flight data. This paper explores the properties of this distribution and demonstrates applications of this data with observed sounding rocket re-entry body damage characteristics to assess probabilities of sustaining various levels of heating damage. The results from this paper effectively bridge the gap existing in sounding rocket reentry analysis between the known damage level/flight environment relationships and the predicted flight environment.

  8. Does Offender Gambling on the inside Continue on the outside? Insights from Correctional Professionals on Gambling and Re-Entry

    ERIC Educational Resources Information Center

    Williams, D. J.; Walker, Gordon J.

    2009-01-01

    This study brings to light a neglected topic of particular importance--offender gambling issues within the context of re-entry into the community. Fifteen correctional professionals from Nevada (high gambling availability) and Utah (no legalized gambling) participated in semi-structured interviews to provide insights into how gambling may impact…

  9. Does Offender Gambling on the inside Continue on the outside? Insights from Correctional Professionals on Gambling and Re-Entry

    ERIC Educational Resources Information Center

    Williams, D. J.; Walker, Gordon J.

    2009-01-01

    This study brings to light a neglected topic of particular importance--offender gambling issues within the context of re-entry into the community. Fifteen correctional professionals from Nevada (high gambling availability) and Utah (no legalized gambling) participated in semi-structured interviews to provide insights into how gambling may impact…

  10. The Role of Counselling and Parental Encouragement on Re-Entry of Adolescents into Secondary Schools in Abia State, Nigeria

    ERIC Educational Resources Information Center

    Alika, Henrietta Ijeoma; Ohanaka, Blessing Ijeoma

    2013-01-01

    This paper examined the role of counselling, and parental encouragement on re-entry of adolescents into secondary school in Abia State, Nigeria. A total of 353 adolescents who re-entered school were selected from six secondary schools in the State through a simple random sampling technique. A validated questionnaire was used for data analysis.…

  11. Career Assessment, Remediation, Education, Employment, and Re-entry Program (CAREER). El Paso Community College Career Grant. Final Report.

    ERIC Educational Resources Information Center

    LaFleur, Carol A.

    Objectives of the Career Assessment, Remediation, Education, Employment, and Re-entry (CAREER) project were to establish a series of intensive, short-term job training programs using competency-based instruction to serve Hispanic persons who were economically disadvantaged, displaced, unemployed, or underemployed, as well as Hispanic females who…

  12. An Exploration of Factors Reducing Recidivism Rates of Formerly Incarcerated Youth with Disabilities Participating in a Re-Entry Intervention

    ERIC Educational Resources Information Center

    Unruh, Deanne K.; Gau, Jeff M.; Waintrup, Miriam G.

    2009-01-01

    Juvenile offenders are costly to our society in terms of the monetary and social expenditures from the legal system, victims' person costs, and incarceration. The re-entry and community reintegration outcomes for formerly incarcerated youth with a disabling condition are bleak compared to peers without disabilities. In this study, we examined the…

  13. The Role of Counselling and Parental Encouragement on Re-Entry of Adolescents into Secondary Schools in Abia State, Nigeria

    ERIC Educational Resources Information Center

    Alika, Henrietta Ijeoma; Ohanaka, Blessing Ijeoma

    2013-01-01

    This paper examined the role of counselling, and parental encouragement on re-entry of adolescents into secondary school in Abia State, Nigeria. A total of 353 adolescents who re-entered school were selected from six secondary schools in the State through a simple random sampling technique. A validated questionnaire was used for data analysis.…

  14. An Exploration of Factors Reducing Recidivism Rates of Formerly Incarcerated Youth with Disabilities Participating in a Re-Entry Intervention

    ERIC Educational Resources Information Center

    Unruh, Deanne K.; Gau, Jeff M.; Waintrup, Miriam G.

    2009-01-01

    Juvenile offenders are costly to our society in terms of the monetary and social expenditures from the legal system, victims' person costs, and incarceration. The re-entry and community reintegration outcomes for formerly incarcerated youth with a disabling condition are bleak compared to peers without disabilities. In this study, we examined the…

  15. Parasystole due to re-entry as the possible mechanism of ventricular parasystole with second-degree entrance block.

    PubMed

    Kinoshita, Shinji; Katoh, Takakazu; Yoshida, Hiroshi

    2010-05-01

    In 1974, Kinoshita reported a case of 'irregular parasystole' due to type I second-degree entrance block. Since then, many cases of such 'irregular' parasystole have been reported by us. To explain the mechanism of 'irregular' parasystole, two theories have been suggested, namely, 'electrotonic modulation' by Jalife and Moe, and 'type I second-degree entrance block' by us. On the contrary, in 1960, Kinoshita et al. reported a case of concealed bigeminy for the first time. The electrocardiographic findings in concealed bigeminy have suggested that there are dual re-entrant pathways with markedly long effective refractory periods in the re-entrant pathway. We have suggested that parasystole may be caused by re-entry in such re-entrant pathways. In this article, attempts are made to explain the mechanism of all the electrocardiographic findings in our cases of parasystole by 'parasystole due to re-entry'. Using 24 studies on parasystole and 21 studies on concealed extrasystoles that we have reported over 50 years, as well as three exemplary cases in this article, attempts are made to explain all electrocardiographic findings in parasystole by 'parasystole due to re-entry'. The electrocardiographic findings in our previous clinical cases of parasystole and concealed extrasystoles, as well as exemplary cases and diagrams in the present article, strongly suggest 'parasystole due to re-entry' as the mechanism of ventricular parasystole with second-degree entrance block.

  16. Cast Glance Near Infrared Imaging Observations of the Space Shuttle During Hypersonic Re-Entry

    NASA Technical Reports Server (NTRS)

    Tack, Steve; Tomek, Deborah M.; Horvath, Thomas J.; Verstynen, Harry A.; Shea, Edward J.

    2010-01-01

    High resolution calibrated infrared imagery of the Space Shuttle was obtained during hypervelocity atmospheric entries of the STS-119, STS-125 and STS128 missions and has provided information on the distribution of surface temperature and the state of the airflow over the windward surface of the Orbiter during descent. This data collect was initiated by NASA s Hypersonic Thermodynamic Infrared Measurements (HYTHIRM) team and incorporated the use of air- and land-based optical assets to image the Shuttle during atmospheric re-entry. The HYTHIRM objective is to develop and implement a set of mission planning tools designed to establish confidence in the ability of an existing optical asset to reliably acquire, track and return global quantitative surface temperatures of the Shuttle during entry. On Space Shuttle Discovery s STS-119 mission, NASA flew a specially modified thermal protection system tile and instrumentation package to monitor heating effects from boundary layer transition during re-entry. On STS-119, the windward airflow on the port wing was deliberately disrupted by a four-inch wide and quarter-inch tall protuberance built into the modified tile. In coordination with this flight experiment, a US Navy NP-3D Orion aircraft was flown 28 nautical miles below Discovery and remotely monitored surface temperature of the Orbiter at Mach 8.4 using a long-range infrared optical package referred to as Cast Glance. Approximately two months later, the same Navy Cast Glance aircraft successfully monitored the surface temperatures of the Orbiter Atlantis traveling at approximately Mach 14.3 during its return from the successful Hubble repair mission. In contrast to Discovery, Atlantis was not part of the Boundary Layer Transition (BLT) flight experiment, thus the vehicle was not configured with a protuberance on the port wing. In September 2009, Cast Glance was again successful in capturing infrared imagery and monitoring the surface temperatures on Discovery s next

  17. FLPP IXV Re-entry Vehicle, Transonic Characterisation Based on FOI T1500 Wind Tunnel Tests and CFD

    NASA Astrophysics Data System (ADS)

    Torngren, L.; Chiarelli, C.; Mareschi, V.; Tribot, J.-P.; Binetti, P.; Walloschek, T.

    2009-01-01

    The European Space Agency ESA, has engaged in 2004, the IXV project (Intermediate eXperimental Vehicle) which is part of the FLPP (Future Launcher Preparatory Programme) aiming at answering to critical technological issues, while supporting the future generation launchers and to improve in general European capabilities in the strategic field of atmospheric re-entry for space transportation, exploration and scientific applications. The IXV key mission and system objectives are the design, development, manufacturing, assembling and on-ground to in-flight verification of an autonomous European lifting and aerodynamically controlled re-entry system, integrating the critical re-entry technologies at the system level. The current IXV vehicle is a slender body type exhibiting rounded shape, thick body controlled by means of two control surfaces. The current mission is to perform an atmospheric re- entry ended by a safe recovery in supersonic regime. A potential extension of the flight domain down to the transonic regime was proposed to be analyzed. The objectives were to study the capability of the IXV for flying autonomously enabling a recovery of the vehicle by means of a subsonic parachute based DRS. The vehicle designed for the hypersonic speeds integrating a large base with only two control surfaces located close to the plane of symmetry is definitively not tuned for transonic ones. CFD done by Thales Alenia Space and wind tunnel activities involving FOI T1500 facility contributed to built up an Aerodynamic Data Base (AEDB) to be used as inputs for flying qualities analysis and re-entry simulations. The paper presents the main objectives of the transonic activities with emphasis on CFD and WTT including a description of the different prediction tools and discussing the main outcomes of the current data comparisons.

  18. Re-Entry Aeroheating Analysis of Tile-Repair Augers for the Shuttle Orbiter

    NASA Technical Reports Server (NTRS)

    Mazaheri, Ali R.; Wood, William A.

    2007-01-01

    Computational re-entry aerothermodynamic analysis of the Space Shuttle Orbiter s tile overlay repair (TOR) sub-assembly is presented. Entry aeroheating analyses are conducted to characterize the aerothermodynamic environment of the TOR and to provide necessary inputs for future TOR thermal and structural analyses. The TOR sub-assembly consists of a thin plate and several augers and spacers that serve as the TOR fasteners. For the computational analysis, the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA) is used. A 5-species non-equilibrium chemistry model with a finite rate catalytic recombination model and a radiation equilibrium wall condition are used. It is assumed that wall properties are the same as reaction cured glass (RCG) properties with a surface emissivity of epsilon = 0.89. Surface heat transfer rates for the TOR and tile repair augers (TRA) are computed at a STS-107 trajectory point corresponding to Mach 18 free stream conditions. Computational results show that the average heating bump factor (BF), which is a ratio of local heat transfer rate to a design reference point located at the damage site, for the auger head alone is about 1.9. It is also shown that the average BF for the combined auger and washer heads is about 2.0.

  19. Novel Hybrid Ablative/Ceramic Heatshield for Earth Atmospheric Re-Entry

    NASA Astrophysics Data System (ADS)

    Barcena, J.; Florez, S.; Perez, B.; Pinaud, G.; Bouilly, J.-M.; Fischer, W. P. P.; de Montburn, A.; Descomps, M.; Zuber, C.; Rotaermel, W.; Hald, H.; Pereira, C.; Mergia, K.; Triantou, K.; Marinou, A.; Vekinis, G.; Ionescu, G.; Ban, C.; Stefan, A.; Leroy, V.; Bernard, D.; Massuti, B.; Herdrich, G.

    2014-06-01

    Original approaches based on ablative materials and novel TPS solutions are required for space applications, where resistance to extreme oxidative environments and high temperatures are required. For future space exploration the demands for the thermal shield go beyond the current state-of-the-art. Therefore, the development of new thermal protection materials and systems at a reasonable mass budget is absolutely essential to ensure European non-dependence on corresponding restricted technologies. The three year long FP7 project HYDRA aims at the development of a novel thermal protection system through the integration of a low density ablative outer-shield on top of an advanced thermo-structural ceramic composite layer and will provide an innovative technology solution consistent with the capabilities of European technologies and material providers. This paper summarizes the current status of the scientific activities carried out after two years of progress in terms of design, integration and verification of a robust and lightweight thermal shield solution for atmospheric earth re-entry.

  20. SCRAMP: The Development of an Advanced Planetary Probe From CFD to Re-entry Test Flight

    NASA Technical Reports Server (NTRS)

    Murbach, Marcus S.

    2005-01-01

    The development of a very stable and lightweight planetary entry probe termed SCRAMP (Slotted Compression RAM Probe) is described. The probe geometry is comprised of a sphere-cylinder forebody with a larger diameter flare-skirt aft-body which produces most of the drag (Figure 1). The geometry permits a large static margin due to the separation of the payload/forebody and relatively lightweight aft-body. The CFD and initial ballistic range tests are presented. In addition, several sub-orbital test flights were conducted using the sounding rocket-based SOAREX (Sub-orbital Aerodynamic Re-entry Experiments) test flight series. The dynamic stability was demonstrated from the very quick recovery of the design flight attitude from a tumble induced from the exo-atmospheric deployment (Figure 2). For certain future planetary missions such as network and companion missions, this new probe configuration may be particularly attractive. The latter is due to the overall reduction in mass, as well as the elimination of the gyroscopic stabilization systems required in the current generation of Newtonian sphere-cone derived configurations

  1. An Experimental Study on Aerothermal Heating of the IXV Configuration During Re-Entry

    NASA Astrophysics Data System (ADS)

    Neeb, D.; Gülhan, A.; Cosson, E.; Ameziane, R.; Binetti, P.; Walloschek, T.

    2009-01-01

    In the frame of the ESA FLPP program an experimental study on the aerothermodynamic phenomena during re- entry phase of the IXV configuration has been conducted in the hypersonic wind tunnel H2K Cologne. Tests have been carried out at Mach 8.7, three different Reynolds numbers, different flap deflection and angles of attack. The model is made of a material with low thermal conductivity, in order to measure the surface temperature distribution by means of IR thermography and to avoid any lateral heat dissipation inside the structure. Using this data the heat flux rate has been determined taking into account temperature-dependent material characteristics assuming a semi infinite wall and radiative cooling to the environment. The flow topology has been analysed using Schlieren images. Depending on the combination of the flap deflection angle and angle of attack the experimental data show a significant influence of the Reynolds number on the Shock Wave - Shock Wave (SWSWI) and Shock Wave - Boundary Layer Interactions (SWBLI), flow separation and its re-attachment leading to remarkable differences in the aerothermal heating on the flap.

  2. Landing Characteristics of a Re-entry Vehicle with a Passive Landing System for Impact Alleviation

    NASA Technical Reports Server (NTRS)

    1963-01-01

    Landing Characteristics of a Re-entry Vehicle with a Passive Landing System for Impact Alleviation. An experimental investigation was made to determine the landing characteristics of a 1/8-scale dynamic model of a reentry vehicle using a passive landing system to alleviate the landing-impact loads. The passive landing system consisted of a flexible heat shield with a small section of aluminum honeycomb placed between the heat shield and the crew compartment at the point that would be the first to contact the landing surface. The model was landed on concrete and sand landing surfaces at parachute letdown velocities. The investigations simulated a vertical velocity of 30 ft/sec (full scale), horizontal velocities of 0, 15, 30, 40, and 50 ft/sec (full scale), and landing attitudes ranging from -30 degrees to 20 degrees. The model investigation indicated that stable landings could be made on a concrete surface at horizontal velocities up to about 30 ft/sec, but the stable landing-attitude range at these speeds was small. The aluminum honeycomb bottomed occasionally during landings on concrete. When bottoming did not occur, maximum normal and longitudinal accelerations at the center of gravity of the vehicle were approximately 50g and 30g, respectively. [Entire movie available on DVD from CASI as Doc ID 20070030981. Contact help@sti.nasa.gov

  3. Landing Characteristics of a Re-entry Vehicle with Canted Multiple Air Bag Load Alleviation System

    NASA Technical Reports Server (NTRS)

    1963-01-01

    Investigation of the Landing Characteristics of a Re-entry Vehicle Having a Canted Multiple Air Bag Load Alleviation System. An investigation was made to determine the landing-impact characteristics of a reentry vehicle having a multiple-air-bag load-alleviation system. A 1/16-scale dynamic model having four canted air bags was tested at flight-path angles of 90 degrees (vertical), 45 degrees, and 27 degrees for a parachute or paraglider vertical letdown velocity of 30 feet per second (full scale). Landings were made on concrete at attitudes ranging from -l5 degrees to 20 degrees. The friction coefficient between the model heat shield and the concrete was approximately 0.4. An aluminum diaphragm, designed to rupture at 10.8 pounds per square inch gage, was used to maintain initial pressure in the air bags for a short time period. [Entire movie available on DVD from CASI as Doc ID 20070030986. Contact help@sti.nasa.gov

  4. Nde1-mediated inhibition of ciliogenesis affects cell cycle re-entry

    PubMed Central

    Kim, Sehyun; Zaghloul, Norann A.; Bubenshchikova, Ekaterina; Oh, Edwin C.; Rankin, Susannah; Katsanis, Nicholas; Obara, Tomoko; Tsiokas, Leonidas

    2011-01-01

    The primary cilium is an antenna-like organelle that is dynamically regulated during the cell cycle. Ciliogenesis is initiated as cells enter quiescence, while cilium resorption precedes mitosis. The mechanisms coordinating ciliogenesis with the cell cycle are unknown. Here we identify the centrosomal protein, Nde1, as a negative regulator of ciliary length. Nde1 is expressed at high levels in mitosis, low levels in quiescence and localizes at the mother centriole, which nucleates the primary cilium. Cells depleted of Nde1 show longer cilia and a delay in cell cycle re-entry that correlates with ciliary length. Knockdown of Nde1 in zebrafish embryos results in increased ciliary length, suppression of cell division, reduction of the number of cells forming the Kupffer’s vesicle, and left-right patterning defects. These data suggest that Nde1 is an integral component of a network coordinating ciliary length with cell cycle progression and have implications in the transition from quiescence to a proliferative state. PMID:21394081

  5. Neutral composition measurements by the Pioneer Venus Neutral Mass Spectrometer during Orbiter re-entry

    NASA Astrophysics Data System (ADS)

    Kasprzak, W. T.; Niemann, H. B.; Hedin, A. E.; Bougher, S. W.; Hunten, D. M.

    1993-12-01

    Measurements by the Pioneer Venus Orbiter Neutral Mass Spectrometer (ONMS) instrument during Orbiter re-entry have been made from 18-24 hours local solar time, above 170 km, of He, and from midnight to 4.5 hours below 200 km of He, N, O, CO, N2, and CO2. Preliminary results indicate that in the post-midnight sector He is the dominant species above 170 km, O the dominant species from 140-170 km and CO2 the dominant species below 140 km. Estimated scale height temperatures for He, O and CO2 of about 105-120 K are similar to those observed in 1978-80 at higher solar activity. The densities at 1 am local solar time and at 150 km are within 35% of those measured earlier. The He bulge is also similar to that observed in 1978-80 confirming that thermosphere superrotation is still present. Comparison with the results of a Venus Thermosphere General Circulation Model suggests the nightside is not sensitive to changes in solar activity due to the isolation of the day and night thermospheres. Apparently, the relatively small changes in the dayside thermosphere with solar activity have little impact on the nightside thermosphere.

  6. Mathematical Interpretation of Observational Data of the Stardust SRC Re-Entry

    NASA Astrophysics Data System (ADS)

    Gritsevich, M. I.

    2009-01-01

    STARDUST spacecraft was launched on February 7, 1999. STARDUST is the first U.S. Space mission dedicated solely to the exploration of a comet, and the first robotic mission designed to return extraterrestrial material from outside the orbit of the Moon. But studying of observational data of the STARDUST Sample Return Capsule's (SRC) entry into Earth's atmosphere on January 15, 2006, also represent a big interest. At a velocity of 12.8 km/s (assumed to be at an altitude of 125 km) SRC was the fastest ever attempted re-entry of a human made space vehicle. The return trajectory of the SRC is very similar to that of natural cosmic bodies. Entry begins when the spacecraft reorients for SRC release from the spacecraft bus and ends with parachute deployment. In the present report, an analytical model of the atmospheric entry is calculated using the data of actual observations, by selecting the parameters describing rate of deceleration of the body during its hypersonic flight. Model was applied to the observational data of STARDUST Sample Return Capsule (a hypersonic phase). The estimate of mass of SRC obtained using the data of actual observations is quite close to its real value of 45.8 kg.

  7. A multiblock analysis for shuttle orbiter re-entry heating from Mach 24 to Mach 12

    NASA Technical Reports Server (NTRS)

    Gnoffo, Peter A.; Weilmuenster, K. J.; Alter, Stephen J.

    1993-01-01

    A multiblock, laminar heating analysis for the shuttle orbiter at three trajectory points ranging from Mach 24.3 to Mach 12.86 on re-entry is described. The analysis is performed using the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA) with both a seven species chemical nonequilibrium model and an equilibrium model. A finite-catalytic-wall model appropriate for shuttle tiles at a radiative equilibrium wall temperature is applied. Computed heating levels are generally in good agreement with the flight data though a few rather large discrepancies remain unexplained. The multiblock relaxation strategy partitions the flowfield into manageable blocks requiring a fraction of the computational resources (time and memory) required by a full domain approach. In hot, the computational cost for a solution at even a single trajectory point would be prohibitively expensive at the given resolution without the multiblock approach. Converged blocks are reassembled to enable a fully coupled converged solution over the entire vehicle, starting from a nearly converged initial condition.

  8. Ceramic Adhesive and Methods for On-Orbit Repair of Re-Entry Vehicles

    NASA Technical Reports Server (NTRS)

    Riedell, James A.; Easler, Timothy E.

    2013-01-01

    This adhesive is capable of repairing damaged leading edge components of reentry vehicles while in space, and is novel with regard to its ability to be applied in the vacuum of space, and in a microgravity environment. Once applied, the adhesive provides thermal and oxidation protection to the substrate (in this case, reinforced carbon/carbon composites, RCCs) during re-entry of a space vehicle. Although there may be many formulations for repair adhesives, at the time of this reporting, this is the first known adhesive capable of an on-orbit repair. The adhesive is an engineered ceramic material composed of a pre-ceramic polymer and refractory powders in the form of a paste or putty that can be applied to a scratched, cracked, or fractured composite surface, covering and protecting the damaged area. The adhesive is then "cured" with a heat cycle, thereby cross-linking the polymer into a hardened material and bonding it to the substrate. During the heat of reentry, the material is converted to a ceramic coating that provides thermal and oxidative stability to the repaired area, thus allowing the vehicle to pass safely from space into the upper atmosphere. Ceramic powders such as SiC, ZrB2 and Y2O3 are combined with allylhydridopolycarbosilane (AHPCS) resin, and are mixed to form a paste adhesive. The material is then applied to the damaged area by brush, spatula, trowel, or other means to fill cracks, gaps, and holes, or used to bond patches onto the damaged area. The material is then cured, in a vacuum, preferably at 250F (approximately equal to 121C) for two hours. The re-entry heating of the vehicle at temperatures in excess of 3,000F (approximately equal to 1,650C) then converts this material into a ceramic coating. This invention has demonstrated advantages in resistance to high temperatures, as was demonstrated in more than 100 arc-jet tests in representative environments at NASA. Extensive testing verified oxidation protection for the repaired substrate (RCC

  9. An Automated Method to Compute Orbital Re-Entry Trajectories with Heating Constraints

    NASA Technical Reports Server (NTRS)

    Zimmerman, Curtis; Dukeman, Greg; Hanson, John; Fogle, Frank R. (Technical Monitor)

    2002-01-01

    Determining how to properly manipulate the controls of a re-entering re-usable launch vehicle (RLV) so that it is able to safely return to Earth and land involves the solution of a two-point boundary value problem (TPBVP). This problem, which can be quite difficult, is traditionally solved on the ground prior to flight. If necessary, a nearly unlimited amount of time is available to find the "best" solution using a variety of trajectory design and optimization tools. The role of entry guidance during flight is to follow the pre-determined reference solution while correcting for any errors encountered along the way. This guidance method is both highly reliable and very efficient in terms of onboard computer resources. There is a growing interest in a style of entry guidance that places the responsibility of solving the TPBVP in the actual entry guidance flight software. Here there is very limited computer time. The powerful, but finicky, mathematical tools used by trajectory designers on the ground cannot in general be made to do the job. Nonconvergence or slow convergence can result in disaster. The challenges of designing such an algorithm are numerous and difficult. Yet the payoff (in the form of decreased operational costs and increased safety) can be substantial. This paper presents an algorithm that incorporates features of both types of guidance strategies. It takes an initial RLV orbital re-entry state and finds a trajectory that will safely transport the vehicle to a Terminal Area Energy Management (TAEM) region. During actual flight, the computed trajectory is used as the reference to be flown by a more traditional guidance method.

  10. Benchmark Shock Tube Experiments for Radiative Heating Relevant to Earth Re-Entry

    NASA Technical Reports Server (NTRS)

    Brandis, A. M.; Cruden, B. A.

    2017-01-01

    Detailed spectrally and spatially resolved radiance has been measured in the Electric Arc Shock Tube (EAST) facility for conditions relevant to high speed entry into a variety of atmospheres, including Earth, Venus, Titan, Mars and the Outer Planets. The tests that measured radiation relevant for Earth re-entry are the focus of this work and are taken from campaigns 47, 50, 52 and 57. These tests covered conditions from 8 km/s to 15.5 km/s at initial pressures ranging from 0.05 Torr to 1 Torr, of which shots at 0.1 and 0.2 Torr are analyzed in this paper. These conditions cover a range of points of interest for potential fight missions, including return from Low Earth Orbit, the Moon and Mars. The large volume of testing available from EAST is useful for statistical analysis of radiation data, but is problematic for identifying representative experiments for performing detailed analysis. Therefore, the intent of this paper is to select a subset of benchmark test data that can be considered for further detailed study. These benchmark shots are intended to provide more accessible data sets for future code validation studies and facility-to-facility comparisons. The shots that have been selected as benchmark data are the ones in closest agreement to a line of best fit through all of the EAST results, whilst also showing the best experimental characteristics, such as test time and convergence to equilibrium. The EAST data are presented in different formats for analysis. These data include the spectral radiance at equilibrium, the spatial dependence of radiance over defined wavelength ranges and the mean non-equilibrium spectral radiance (so-called 'spectral non-equilibrium metric'). All the information needed to simulate each experimental trace, including free-stream conditions, shock time of arrival (i.e. x-t) relation, and the spectral and spatial resolution functions, are provided.

  11. An Automated Method to Compute Orbital Re-entry Trajectories with Heating Constraints

    NASA Technical Reports Server (NTRS)

    Zimmerman, Curtis; Dukeman, Greg; Hanson, John; Fogle, Frank R. (Technical Monitor)

    2002-01-01

    Determining how to properly manipulate the controls of a re-entering re-usable launch vehicle (RLV) so that it is able to safely return to Earth and land involves the solution of a two-point boundary value problem (TPBVP). This problem, which can be quite difficult, is traditionally solved on the ground prior to flight. If necessary, a nearly unlimited amount of time is available to find the 'best' solution using a variety of trajectory design and optimization tools. The role of entry guidance during flight is to follow the pre- determined reference solution while correcting for any errors encountered along the way. This guidance method is both highly reliable and very efficient in terms of onboard computer resources. There is a growing interest in a style of entry guidance that places the responsibility of solving the TPBVP in the actual entry guidance flight software. Here there is very limited computer time. The powerful, but finicky, mathematical tools used by trajectory designers on the ground cannot in general be converted to do the job. Non-convergence or slow convergence can result in disaster. The challenges of designing such an algorithm are numerous and difficult. Yet the payoff (in the form of decreased operational costs and increased safety) can be substantiaL This paper presents an algorithm that incorporates features of both types of guidance strategies. It takes an initial RLV orbital re-entry state and finds a trajectory that will safely transport the vehicle to Earth. During actual flight, the computed trajectory is used as the reference to be flown by a more traditional guidance method.

  12. Romance, recovery & community re-entry for criminal justice involved women: Conceptualizing and measuring intimate relationship factors and power.

    PubMed

    Walt, Lisa C; Hunter, Bronwyn; Salina, Doreen; Jason, Leonard

    Researchers have suggested that interpersonal relationships, particularly romantic relationships, may influence women's attempts at substance abuse recovery and community re-entry after criminal justice system involvement. The present paper evaluates relational and power theories to conceptualize the influence of romantic partner and romantic relationship qualities on pathways in and out of substance abuse and crime. The paper then combines these conceptualizations with a complementary empirical analysis to describe an ongoing research project that longitudinally investigates these relational and power driven factors on women's substance abuse recovery and community re-entry success among former substance abusing, recently criminally involved women. This paper is designed to encourage the integration of theory and empirical analysis by detailing how each of these concepts are operationalized and measured. Future research and clinical implications are also discussed.

  13. Assessment Of The Aerodynamic And Aerothermodynamic Performance Of The USV-3 High-Lift Re-Entry Vehicle

    NASA Astrophysics Data System (ADS)

    Pezzella, Giuseppe; Richiello, Camillo; Russo, Gennaro

    2011-05-01

    This paper deals with the aerodynamic and aerothermodynamic trade-off analysis carried out with the aim to design a hypersonic flying test bed (FTB), namely USV3. Such vehicle will have to be launched with a small expendable launcher and shall re-enter the Earth atmosphere allowing to perform several experiments on critical re-entry phenomena. The demonstrator under study is a re-entry space glider characterized by a relatively simple vehicle architecture able to validate hypersonic aerothermodynamic design database and passenger experiments, including thermal shield and hot structures. Then, a summary review of the aerodynamic characteristics of two FTB concepts, compliant with a phase-A design level, has been provided hereinafter. Indeed, several design results, based both on engineering approach and computational fluid dynamics, are reported and discussed in the paper.

  14. Analysis of Electromagnetic Wave Propagation in a Magnetized Re-Entry Plasma Sheath Via the Kinetic Equation

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    2009-01-01

    Based on a theoretical model of the propagation of electromagnetic waves through a hypersonically induced plasma, it has been demonstrated that the classical radiofrequency communications blackout that is experienced during atmospheric reentry can be mitigated through the appropriate control of an external magnetic field of nominal magnitude. The model is based on the kinetic equation treatment of Vlasov and involves an analytical solution for the electric and magnetic fields within the plasma allowing for a description of the attendant transmission, reflection and absorption coefficients. The ability to transmit through the magnetized plasma is due to the magnetic windows that are created within the plasma via the well-known whistler modes of propagation. The case of 2 GHz transmission through a re-entry plasma is considered. The coefficients are found to be highly sensitive to the prevailing electron density and will thus require a dynamic control mechanism to vary the magnetic field as the plasma evolves through the re-entry phase.

  15. Romance, recovery & community re-entry for criminal justice involved women: Conceptualizing and measuring intimate relationship factors and power

    PubMed Central

    Walt, Lisa C.; Hunter, Bronwyn; Salina, Doreen; Jason, Leonard

    2015-01-01

    Researchers have suggested that interpersonal relationships, particularly romantic relationships, may influence women’s attempts at substance abuse recovery and community re-entry after criminal justice system involvement. The present paper evaluates relational and power theories to conceptualize the influence of romantic partner and romantic relationship qualities on pathways in and out of substance abuse and crime. The paper then combines these conceptualizations with a complementary empirical analysis to describe an ongoing research project that longitudinally investigates these relational and power driven factors on women’s substance abuse recovery and community re-entry success among former substance abusing, recently criminally involved women. This paper is designed to encourage the integration of theory and empirical analysis by detailing how each of these concepts are operationalized and measured. Future research and clinical implications are also discussed. PMID:25750487

  16. Pre-X Experimental Re-Entry Lifting Body: Design of Flight Test Experiments for Critical Aerothermal Phenomena

    DTIC Science & Technology

    2007-06-01

    hypersonic domain has never been explored with a controlled glider . BOR 4 BOR 5 The hypersonic glider HYFLEX The main concrete...the most critical phenomena concerning the design and sizing of a re- entry vehicle. Pre-X hypersonic glider • Improving the flight measurement...laws of a gliding body with body flaps. • Performing the first design and development end to end of the hypersonic glider . • To reduce risk for

  17. The characteristics of registered nurses whose licenses expire: why they leave nursing and implications for retention and re-entry.

    PubMed

    Skillman, Susan M; Palazzo, Lorella; Hart, L Gary; Keepnews, David

    2010-01-01

    Little is known about RNs who drop their licenses and their potential re-entry into the nursing workforce. The results of this study provide insight into reasons nurses leave their careers and the barriers to re-entry, all important indicators of the current professional climate for nursing. While representing only one state, these findings suggest that RNs who allow their licenses to expire do so because they have reached retirement age or, among those who do not cite age as a factor, because many are unable or unwilling to work in the field. Inactive nurses who might otherwise appear to be likely candidates for re-entry into the profession may not be easily encouraged to practice nursing again without significant changes in their personal circumstances or the health care work environment. Effective ways to address current and pending RN workforce shortages include expanding RN education capacity to produce more RNs who can contribute to the workforce across the coming decades, and promote work environments in which RNs want to, and are able to, practice across a long nursing career.

  18. Potential dermal exposure in greenhouses for manual sprayers: analysis of the mix/load, application and re-entry stages.

    PubMed

    Ramos, Laura M; Querejeta, Giselle A; Flores, Andrea P; Hughes, Enrique A; Zalts, Anita; Montserrat, Javier M

    2010-09-01

    An evaluation of the Potential Dermal Exposure for the mix/load, application and re-entry stages, associated with procymidone and deltamethrin usage, was carried out for tomatoes grown in greenhouses of small production units in Argentina. Eight experiments were done with four different operators, under typical field conditions with a lever operated backpack sprayer. The methodology applied was based on the Whole Body Dosimetry technique, evaluating a set of different data for the mix and load, application and re-entry operations. These results indicated that the Potential Dermal Exposure of the application step was (38+/-17)mLh(-1) with the highest proportion on torso, head and arms. When the three stages were compared, re-entry was found to contribute least towards the total Potential Dermal Exposure; meanwhile in all cases, except one, the mix/load operation was the stage with highest exposure. The Margin of Safety for each different operation was also calculated and the proportion of pesticide drift from the greenhouse to the environment is presented. These results emphasize the importance of improving the personal protection measures in the mix and load stage, an operation that is not usually associated with high-risk in small production units.

  19. Aerothermodynamic performance and thermal protection design for blunt re-entry bodies at L/D = 0.3

    NASA Technical Reports Server (NTRS)

    Caram, Jose M.; Kowal, T. J.

    1993-01-01

    Aerodynamic heating and thermal protection design analyses were performed for three blunt re-entry bodies at an L/D = 0.3 returning from low earth orbit. These configurations consisted of a scaled up Apollo command module, a Viking re-entry vehicle, and an Aeroassist Flight Experiment (AFE) aerobrake, each with a maximum diameter of 4.42 m. The aerothermodynamic analysis determined the equilibrium stagnation point heating rate and heat load for nominal and 3-sigma re-entry trajectories and the distribution of heating along the pitch and yaw planes for each of the vehicles at the time of highest heat flux. Using the predicted heating rates and heating distributions, a Thermal Protection System (TPS) design with flight certified materials was tailored for each of the configurations. Results indicated that the heating to the corner of the Viking aeroshell would exceed current limits of reusable tile material. Also, the maximum heating for the AFE would be 15 percent greater than the maximum heating for the Apollo flying the same trajectory. TPS designs showed no significant advantage in TPS weight between the different vehicles; however, heat-shield areal density comparisons showed the Apollo configuration to be the most efficient in terms of TPS weight.

  20. Putting principals back into practice: an evaluation of a re-entry course for vocationally trained doctors.

    PubMed Central

    Baker, M; Williams, J; Petchey, R

    1997-01-01

    BACKGROUND: Current recruitment difficulties in general practice have sharpened the interest of the profession in non-principals. No re-entry course for general practice has previously been run in the UK. AIM: To design and evaluate a re-entry course for general practice. METHOD: A re-entry course was developed to help doctors return to general practice as principals. A telephone interview was carried out with each delegate prior to their attendance on the course and was repeated one month and six months after the course to measure any change in career intentions and the perceived benefit of attending the course. RESULTS: Six months after the course, 11 out of 14 delegates had taken positive steps to return to general practice or had increased their time commitment to medicine. This contrasts with only one of the control group having made any steps to change career. CONCLUSION: The course was evaluated and found to be beneficial, particularly in terms of increasing the confidence of the delegates. PMID:9463984

  1. Cardiovascular effects of anti-G suit and cooling garment during space shuttle re-entry and landing

    NASA Technical Reports Server (NTRS)

    Perez, Sondra A.; Charles, John B.; Fortner, G. William; Hurst, Victor 4th; Meck, Janice V.

    2003-01-01

    BACKGROUND: Many cardiovascular changes associated with spaceflight reduce the ability of the cardiovascular system to oppose gravity on return to Earth, leaving astronauts susceptible to orthostatic hypotension during re-entry and landing. Consequently, an anti-G suit was developed to protect arterial pressure during re-entry. A liquid cooling garment (LCG) was then needed to alleviate the thermal stress resulting from use of the launch and entry suit. METHODS: We studied 34 astronauts on 22 flights (4-16 d). Subjects were studied 10 d before launch and on landing day. Preflight, crewmembers were suited with their anti-G suits set to the intended inflation for re-entry. Three consecutive measurements of heart rate and arterial pressure were obtained while seated and then again while standing. Three subjects who inflated the anti-G suits also donned the LCG for landing. Arterial pressure and heart rate were measured every 5 min during the de-orbit maneuver, through maximum G-loading (max-G) and touch down (TD). After TD, crew-members again initiated three seated measurements followed by three standing measurements. RESULTS: Astronauts with inflated anti-G suits had higher arterial pressure than those who did not have inflated anti-G suits during re-entry and landing (133.1 +/- 2.5/76.1 +/- 2.1 vs. 128.3 +/- 4.2/79.3 +/- 2.9, de-orbit; 157.3 +/- 4.5/102.1 +/- 3.6 vs. 145.2 +/- 10.5/95.7 + 5.5, max-G; 159.6 +/- 3.9/103.7 +/- 3.3 vs. 134.1 +/- 5.1/85.7 +/- 3.1, TD). In the group with inflated anti-G suits, those who also wore the LCG exhibited significantly lower heart rates than those who did not (75.7 +/- 11.5 vs. 86.5 +/- 6.2, de-orbit; 79.5 +/- 24.8 vs. 112.1 +/- 8.7, max-G; 84.7 +/- 8.0 vs. 110.5 +/- 7.9, TD). CONCLUSIONS: The anti-G suit is effective in supporting arterial pressure. The addition of the LCG lowers heart rate during re-entry.

  2. Cardiovascular effects of anti-G suit and cooling garment during space shuttle re-entry and landing

    NASA Technical Reports Server (NTRS)

    Perez, Sondra A.; Charles, John B.; Fortner, G. William; Hurst, Victor 4th; Meck, Janice V.

    2003-01-01

    BACKGROUND: Many cardiovascular changes associated with spaceflight reduce the ability of the cardiovascular system to oppose gravity on return to Earth, leaving astronauts susceptible to orthostatic hypotension during re-entry and landing. Consequently, an anti-G suit was developed to protect arterial pressure during re-entry. A liquid cooling garment (LCG) was then needed to alleviate the thermal stress resulting from use of the launch and entry suit. METHODS: We studied 34 astronauts on 22 flights (4-16 d). Subjects were studied 10 d before launch and on landing day. Preflight, crewmembers were suited with their anti-G suits set to the intended inflation for re-entry. Three consecutive measurements of heart rate and arterial pressure were obtained while seated and then again while standing. Three subjects who inflated the anti-G suits also donned the LCG for landing. Arterial pressure and heart rate were measured every 5 min during the de-orbit maneuver, through maximum G-loading (max-G) and touch down (TD). After TD, crew-members again initiated three seated measurements followed by three standing measurements. RESULTS: Astronauts with inflated anti-G suits had higher arterial pressure than those who did not have inflated anti-G suits during re-entry and landing (133.1 +/- 2.5/76.1 +/- 2.1 vs. 128.3 +/- 4.2/79.3 +/- 2.9, de-orbit; 157.3 +/- 4.5/102.1 +/- 3.6 vs. 145.2 +/- 10.5/95.7 + 5.5, max-G; 159.6 +/- 3.9/103.7 +/- 3.3 vs. 134.1 +/- 5.1/85.7 +/- 3.1, TD). In the group with inflated anti-G suits, those who also wore the LCG exhibited significantly lower heart rates than those who did not (75.7 +/- 11.5 vs. 86.5 +/- 6.2, de-orbit; 79.5 +/- 24.8 vs. 112.1 +/- 8.7, max-G; 84.7 +/- 8.0 vs. 110.5 +/- 7.9, TD). CONCLUSIONS: The anti-G suit is effective in supporting arterial pressure. The addition of the LCG lowers heart rate during re-entry.

  3. An integrated approach for risk object re-entry predictions in terms of KS elements and genetic algorithm

    NASA Astrophysics Data System (ADS)

    Sharma, R. K.; Anil Kumar, A. K.; Xavier James Raj, M.

    The accurate estimation of the orbital lifetime of decaying near-Earth objects is of considerable importance for prediction of risk object re-entry time and proper planning of mitigation strategies and hazard assessment. It has become necessary to use extremely complex force models to match with the present operational requirements and observational techniques. The problem becomes all the more complicated in the near-Earth environment due to the fact that the object is influenced by the non-spherical effects of the Earth's gravitational field as well as the dissipative effects of the Earth's atmosphere. The database available for the re-entry time or orbital lifetime prediction of the debris objects is based on the set of Two Line Elements (TLEs) provided by the agencies like NORAD. These TLEs provide information regarding the orbital parameters together with rate of mean motion decay and an equivalent ballistic coefficient B*. The objects physical parameters like mass, area of cross section, shape and dimensions are not available accurately and the modelling of the atmosphere in which objects decay takes place is also uncertain. Besides, the tumbling effect of the body and gas molecular interaction, further makes the prediction of re-entry time a very complicated exercise. The method of the K-S total-energy element equations (Stiefel & Scheifele 1971) is a powerful method for numerical solution with respect to any type of perturbing forces, as the equations are less sensitive to round-off and truncation errors in the numerical algorithm. The equations are everywhere regular in contrast with the classical Newtonian equations, which are singular at the collision of the two bodies. The equations are smoothed for eccentric orbits because eccentric anomaly is the independent variable. Genetic Algorithms (Deb 1995) has received a great deal of attention regarding their potential as an optimisation technique for complex functions. This paper highlights the implementation

  4. A case study of non-traditional students re-entry into college physics and engineering

    NASA Astrophysics Data System (ADS)

    Langton, Stewart Gordon

    Two groups of students in introductory physics courses of an Access Program for engineering technologies were the subjects of this study. Students with a wide range of academic histories and abilities were enrolled in the program; many of the students were re-entry and academically unprepared for post-secondary education. Five years of historical data were evaluated to use as a benchmark for revised instruction. Data were gathered to describe the pre-course academic state of the students and their academic progress during two physics courses. Additional information was used to search for factors that might constrain academic success and as feedback for the instructional methods. The data were interpreted to regulate constructivist design features for the physics courses. The Engineering Technology Access Program was introduced to meet the demand from non-traditional students for admission to two-year engineering' technology programs, but who did not meet normal academic requirements. The duration of the Access Program was two terms for electronic and computer engineering students and three terms for civil and mechanical engineering students. The sequence of mathematics and physics courses was different for the two groups. The Civil/Mechanical students enrolled in their first mathematics course before undertaking their first physics course. The first mathematics and physics courses for the Electronics students were concurrent. Academic success in the two groups was affected by this difference. Over a five-year period the success rate of students graduating with a technology diploma was approximately twenty-five percent. Results from this study indicate that it was possible to reduce the very high attrition in the combined Access/Technology Programs. While the success rate for the Electronics students increased to 38% the rate for the Civil/Mechanical students increased dramatically to 77%. It is likely that several factors, related to the extra term in the Access

  5. Further Investigations of Control Surface Seals for the X-38 Re-Entry Vehicle

    NASA Technical Reports Server (NTRS)

    Dunlap, Patrick H., Jr.; Steinetz, Bruce M.; Curry, Donald M.; Newquist, Charles W.; Verzemnieks, Juris

    2001-01-01

    NASA is currently developing the X-38 vehicle that will be used to demonstrate the technologies required for a potential crew return vehicle (CRV) for the International Space Station. This vehicle would serve both as an ambulance for medical emergencies and as an evacuation vehicle for the Space Station. Control surfaces on the X-38 (body flaps and rudder/fin assemblies) require high temperature seals to limit hot gas ingestion and transfer of heat to underlying low-temperature structures to prevent over-temperature of these structures and possible loss of the vehicle. NASAs Johnson Space Center (JSC) and Glenn Research Center (GRC) are working together to develop and evaluate seals for these control surfaces. This paper presents results for compression. flow, scrub, and arc jet tests conducted on the baseline X-38 rudder/fin seal design. Room temperature seal compression tests were performed at low compression levels to determine load versus linear compression, preload. contact area, stiffness. and resiliency characteristics under low load conditions. For all compression levels that were tested, unit loads and contact pressures for the seals were below the 5 lb/in. and 10 psi limits required to limit the loads on the adjoining Shuttle thermal tiles that the seals will contact. Flow rates through an unloaded (i.e. 0% compression) double arrangement were twice those of a double seal compressed to the 20% design compression level. The seals survived an ambient temperature 1000 cycle scrub test over relatively rough Shuttle tile surfaces. The seals were able to disengage and re-engage the edges of the rub surface tiles while being scrubbed over them. Arc jet tests were performed to experimentally determine anticipated seal temperatures for representative flow boundary conditions (pressures and temperatures) under simulated vehicle re-entry conditions. Installation of a single seat in the gap of the test fixture caused a large temperature drop (1710 F) across the seal

  6. Retrograde access via the popliteal artery to facilitate the re-entry technique for recalcitrant superficial femoral artery chronic total occlusions.

    PubMed

    Pappy, Reji; Hennebry, Thomas A; Abu-Fadel, Mazen S

    2011-10-01

    Subintimal recanalization is beneficial in selected patients with peripheral chronic total occlusions (CTO). However, in complex cases, re-entry into the true arterial lumen may prove to be unsuccessful with a conventional guidewire or a re-entry catheter when using standard femoral artery access. Our case series describes these technical dilemmas along with strategies that can be utilized to overcome these challenges. Copyright © 2011 Wiley-Liss, Inc.

  7. Aero-thermo-dynamic analysis of a low ballistic coefficient deployable capsule in Earth re-entry

    NASA Astrophysics Data System (ADS)

    Zuppardi, G.; Savino, R.; Mongelluzzo, G.

    2016-10-01

    The paper deals with a microsatellite and the related deployable recovery capsule. The aero-brake is folded at launch and deployed in space and is able to perform a de-orbiting controlled re-entry. This kind of capsule, with a flexible, high temperature resistant fabric, thanks to its lightness and modulating capability, can be an alternative to the current ;conventional; recovery capsules. The present authors already analyzed the trajectory and the aerodynamic behavior of low ballistic coefficient capsules during Earth re-entry and Mars entry. In previous studies, aerodynamic longitudinal stability analysis and evaluation of thermal and aerodynamic loads for a possible suborbital re-entry demonstrator were carried out in both continuum and rarefied regimes. The present study is aimed at providing preliminary information about thermal and aerodynamic loads and longitudinal stability for a similar deployable capsule, as well as information about the electronic composition of the plasma sheet and its possible influence on radio communications at the altitudes where GPS black-out could occur. Since the computer tests were carried out at high altitudes, therefore in rarefied flow fields, use of Direct Simulation Monte Carlo codes was mandatory. The computations involved both global aerodynamic quantities (drag and longitudinal moment coefficients) and local aerodynamic quantities (heat flux and pressure distributions along the capsule surface). The results verified that the capsule at high altitude (150 km) is self-stabilizing; it is stable around the nominal attitude or at zero angle of attack and unstable around the reverse attitude or at 180° angle of attack. The analysis also pointed out the presence of extra statically stable equilibrium trim points.

  8. Cardiac tamponade arising from a venous source following anterograde dissection re-entry coronary angioplasty to a chronic total occlusion.

    PubMed

    Danson, E; Arena, F; Sapontis, J; Ward, M; Bhindi, R

    2016-10-01

    Cardiac tamponade is a rare complication of coronary intervention to chronic total occlusions (CTO PCI). We report a case of persistent bleeding from a venous source following successful anterograde dissection-reentry (ADR) CTO PCI. Pericardiocentesis was performed 1 h post-procedure for tamponade. Persistent bleeding was investigated with contrast transesophageal echocardiography, pericardial manometry and blood analysis. Coronary venography revealed subtle extravasation from a cardiac vein adjacent to the site of luminal re-entry. Coronary venous perforation using ADR CTO PCI has not previously been described; however, the volume of blood loss may be significant and surgical exploration may be appropriate.

  9. [Enlargement of keratinized peri-implant mucosa at the time of second stage surgery (re-entry)].

    PubMed

    Kaufmann, Regula; Bassetti, Renzo; Mericske-Stern, Regina; Enkling, Norbert

    2014-01-01

    A tightly attached keratinized mucosa around endosseous dental implants is believed to be protective against peri-implant bone loss. Tension caused by buccal frena and mobile non keratinized mucosa is to avoid. This case report documents the optimization of peri-implant mucosal conditions in the upper and lower jaw. At the time of second stage surgery (re-entry) at submucosally osseointegrated dental implants an enlargement of keratinized mucosa and a thickening of soft tissue was obtained administrating a vestibuloplasty combined by a free gingival graft or a vestibuloplasty combined by an apically moved flap.

  10. A flexible-segment-model-based dynamics calculation method for free hanging marine risers in re-entry

    NASA Astrophysics Data System (ADS)

    Xu, Xue-song; Wang, Sheng-wei

    2012-03-01

    In re-entry, the drilling riser hanging to the holding vessel takes on a free hanging state, waiting to be moved from the initial random position to the wellhead. For the re-entry, dynamics calculation is often done to predict the riser motion or evaluate the structural safety. A dynamics calculation method based on Flexible Segment Model (FSM) is proposed for free hanging marine risers. In FSM, a riser is discretized into a series of flexible segments. For each flexible segment, its deflection feature and external forces are analyzed independently. For the whole riser, the nonlinear governing equations are listed according to the moment equilibrium at nodes. For the solution of the nonlinear equations, a linearization iteration scheme is provided in the paper. Owing to its flexibility, each segment can match a long part of the riser body, which enables that good results can be obtained even with a small number of segments. Moreover, the linearization iteration scheme can avoid widely used Newton-Rapson iteration scheme in which the calculation stability is influenced by the initial points. The FSM-based dynamics calculation is timesaving and stable, so suitable for the shape prediction or real-time control of free hanging marine risers.

  11. Re-entry communication through a plasma sheath using standing wave detection and adaptive data rate control

    NASA Astrophysics Data System (ADS)

    Xie, Kai; Yang, Min; Bai, Bowen; Li, Xiaoping; Zhou, Hui; Guo, Lixin

    2016-01-01

    Radio blackout during the re-entry has puzzled the aerospace industry for decades and has not yet been completely resolved. To achieve a continuous data link in the spacecraft's re-entry period, a simple and practicable communication method is proposed on the basis that (1) the electromagnetic-wave backscatter of the plasma sheath affects the voltage standing wave ratio (VSWR) of the antenna, and the backscatter is negatively correlated to transmission components, and (2) the transmission attenuation caused by the plasma sheath reduces the channel capacity. We detect the voltage standing wave ratio changes of the antenna and then adjust the information rate to accommodate the varying channel capacity, thus guaranteeing continuous transmission (for fewer critical data). The experiment was carried out in a plasma generator with an 18-cm-thick and 30-cm-diameter hollow propagation path, and the adaptive communication was implemented using spread spectrum frequency, shift key modulation with a variable spreading factor. The experimental results indicate that, when the over-threshold of VSWR was detected, the bit rate reduced to 250 bps from 4 Mbps automatically and the tolerated plasma density increased by an order of magnitude, which validates the proposed scheme. The proposed method has little additional cost, and the adaptive control does not require a feedback channel. The method is therefore applicable to data transmission in a single direction, such as that of a one-way telemetry system.

  12. Surgical Re-entry of an Intentionally Replanted Periodontally Compromised Tooth Treated with Platelet Rich Fibrin (PRF): Hopeless to Hopeful

    PubMed Central

    Srinath, Rashmi; Prakash, Shobha

    2016-01-01

    Intentional replantation is generally contraindicated in periodontally compromised teeth however, there are reports suggesting that it can be a successful treatment alternative for periodontally involved hopeless teeth. Currently there is dearth of evidence regarding the success of this therapy, especially evidence for the effectiveness of autologous platelet rich fibrin is lacking. We present a case report of a 23-year-old male patient with periodontally hopeless left maxillary central incisor having bone loss extending beyond root apex. The tooth was gently extracted and replanted utilizing root conditioning and combined regenerative therapy (Xenograft, PRF and Type I Collagen Membrane). Surgical re-entry at nine months revealed bone formation in the apical third of the tooth. At one year, 87% radiographic bone gain was accomplished. The improvement in the clinical and radiographic parameters reinforced by the re-entry surgery findings strongly suggest that intentional replantation may be a cost-effective substitute to implants and tooth supported prosthesis in situations where conventional periodontal therapy would yield compromised outcomes. PMID:27504421

  13. Surgical Re-entry of an Intentionally Replanted Periodontally Compromised Tooth Treated with Platelet Rich Fibrin (PRF): Hopeless to Hopeful.

    PubMed

    Ryana, Haneet Kour; Srinath, Rashmi; Prakash, Shobha

    2016-06-01

    Intentional replantation is generally contraindicated in periodontally compromised teeth however, there are reports suggesting that it can be a successful treatment alternative for periodontally involved hopeless teeth. Currently there is dearth of evidence regarding the success of this therapy, especially evidence for the effectiveness of autologous platelet rich fibrin is lacking. We present a case report of a 23-year-old male patient with periodontally hopeless left maxillary central incisor having bone loss extending beyond root apex. The tooth was gently extracted and replanted utilizing root conditioning and combined regenerative therapy (Xenograft, PRF and Type I Collagen Membrane). Surgical re-entry at nine months revealed bone formation in the apical third of the tooth. At one year, 87% radiographic bone gain was accomplished. The improvement in the clinical and radiographic parameters reinforced by the re-entry surgery findings strongly suggest that intentional replantation may be a cost-effective substitute to implants and tooth supported prosthesis in situations where conventional periodontal therapy would yield compromised outcomes.

  14. Is the time dimension of the cell cycle re-entry in AD regulated by centromere cohesion dynamics?

    PubMed

    Bajić, Vladan P; Spremo-Potparević, Biljana; Zivković, Lada; Djelić, Ninoslav; Smith, Mark A

    2008-01-01

    Chromosomal involvement is a legitimate, yet not well understood, feature of Alzheimer disease (AD). Firstly, AD affects more women than men. Secondly, the amyloid-β protein precursor genetic mutations, responsible for a cohort of familial AD cases, reside on chromosome 21, the same chromosome responsible for the developmental disorder Down's syndrome. Thirdly, lymphocytes from AD patients display a novel chromosomal phenotype, namely premature centromere separation (PCS). Other documented morphological phenomena associated with AD include the occurrence of micronuclei, aneuploidy, binucleation, telomere instability, and cell cycle re-entry protein expression. Based on these events, here we present a novel hypothesis that the time dimension of cell cycle re-entry in AD is highly regulated by centromere cohesion dynamics. In view of the fact that neurons can re-enter the cell division cycle, our hypothesis predicts that alterations in the signaling pathway leading to premature cell death in neurons is a consequence of altered regulation of the separation of centromeres as a function of time. It is well known that centromeres in the metaphase-anaphase transition separate in a non-random, sequential order. This sequence has been shown to be deregulated in aging cells, various tumors, syndromes of chromosome instability, following certain chemical inductions, as well as in AD. Over time, premature chromosome separation is both a result of, and a driving force behind, further cohesion impairment, activation of cyclin dependent kinases, and mitotic catastrophe, a vicious circle resulting in cellular degeneration and death.

  15. Evaluation of the Positive Re-Entry in Corrections Program: A Positive Psychology Intervention With Prison Inmates.

    PubMed

    Huynh, Kim H; Hall, Brittany; Hurst, Mark A; Bikos, Lynette H

    2015-08-01

    Two groups of male inmates (n = 31, n = 31) participated in the Positive Re-Entry in Corrections Program (PRCP). This positive psychology intervention focused on teaching offenders skills that facilitate re-entry into the community. Offenders participated in weekly lectures, discussions, and homework assignments focused on positive psychology principles. The two groups differed in duration of treatment (8 weeks and 12 weeks). Participants completed pre- and post-intervention measures of gratitude, hope, and life satisfaction. Using a 2 × 2 mixed design ANOVA, we hypothesized that the intervention (with two between-subjects levels of 8 and 12 weeks) and duration (with two repeated measures levels of pre and post) of treatment would moderate pre- to post-intervention change. Results indicated significant differences on pre- and post-intervention scores for both groups of offenders on all measures. The analysis did not yield statistically significant differences between groups, demonstrating no additive benefits from the inclusion of four additional sessions, thus saving time and money for correctional programming and funding. This research supports the use of positive psychology in prison interventions. © The Author(s) 2014.

  16. Advanced Models for Prediction of High Altitude Aero-Thermal Loads of a Space Re-entry Vehicle

    NASA Astrophysics Data System (ADS)

    Votta, R.; Schettino, A.; Bonfiglioli, A.

    2011-05-01

    The analysis of the rarefaction effects in predicting the main aero-thermal loads of a Space re-entry vehicle is presented. It is well known that the Navier-Stokes equations fail in rarefied regimes and other approaches must be used. In the present paper different configurations have been simulated by using the Direct Simulation Monte Carlo method. Moreover, slip flow boundary conditions have been implemented in a Navier-Stokes code in order to extend the validity of the continuum approach to the transitional flow regime. Finally, bridging formulas for high altitude aerodynamics of winged bodies have been used. Firstly, two simple geometries have been analysed, specifically designed to study the phenomenon of shock wave boundary layer interaction: a hollow cylinder flare, for which some experiments are available; and a blunt-nosed flat plate/flap model designed and tested at the Italian Aerospace Research Centre. The other configurations taken into account are, respectively, an experimental winged re-entry vehicle and a capsule, for which global aerodynamic coefficients and local wall heating have been determined with different approaches. The Navier-Stokes code with slip flow boundary conditions has shown good predicting capabilities compared with experiments in the hollow cylinder flare case; however, for the winged vehicle and capsule cases, the CFD results are not fully satisfactory and the Monte Carlo method remains the most reliable approach, together with the bridging formula, that provides good results for the aerodynamic coefficients.

  17. Analytical solutions for the equations of motion of a space vehicle during the atmospheric re-entry phase on a 2-D trajectory

    NASA Astrophysics Data System (ADS)

    Mititelu, Gabriel

    2009-04-01

    A practical and important problem encountered during the atmospheric re-entry phase is to determine analytical solutions for the space vehicle dynamical equations of motion. The author proposes new solutions for the equations of trajectory and flight-path angle of the space vehicle during the re-entry phase in Earth’s atmosphere. Explicit analytical solutions for the aerodynamic equations of motion can be effectively applied to investigate and control the rocket flight characteristics. Setting the initial conditions for the speed, re-entering flight-path angle, altitude, atmosphere density, lift and drag coefficients, the nonlinear differential equations of motion are linearized by a proper choice of the re-entry range angles. After integration, the solutions are expressed with the Exponential Integral, and Generalized Exponential Integral functions. Theoretical frameworks for proposed solutions as well as, several numerical examples, are presented.

  18. Novel Hybrid Ablative/Ceramic Layered Composite for Earth Re-entry Thermal Protection: Microstructural and Mechanical Performance

    NASA Astrophysics Data System (ADS)

    Triantou, K.; Mergia, K.; Marinou, A.; Vekinis, G.; Barcena, J.; Florez, S.; Perez, B.; Pinaud, G.; Bouilly, J.-M.; Fischer, W. P. P.

    2015-04-01

    In view of spacecraft re-entry applications into planetary atmospheres, hybrid thermal protection systems based on layered composites of ablative materials and ceramic matrix composites are investigated. Joints of ASTERM™ lightweight ablative material with Cf/SiC (SICARBON™) were fabricated using commercial high temperature inorganic adhesives. Sound joints without defects are produced and very good bonding of the adhesive with both base materials is observed. Mechanical shear tests under ambient conditions and in liquid nitrogen show that mechanical failure always takes place inside the ablative material with no decohesion of the interface of the adhesive layer with the bonded materials. Surface treatment of the ablative surface prior to bonding enhances both the shear strength and the ultimate shear strain by up to about 60%.

  19. The IXV Avionics & Software Architecture for the On-Board Management of the Autonomous Re-Entry Vehicle

    NASA Astrophysics Data System (ADS)

    Malocchi, Giovanni; Angelini, Roberto; Dussy, Stephane

    2016-08-01

    This paper focuses on the Intermediate eXperimental Vehicle (IXV), the first European glider successfully performing an autonomous atmospheric re-entry from a suborbital LEO trajectory. An introduction of the mission objectives is provided, describing the selected trajectory envelope and the main spacecraft features. Core of the paper is the presentation of the Avionics and Software architecture, analyzed through the constituting subsystems and equipment, from the perspective of the mission autonomy needs and constraints.The launch campaign activities involving the IXV Avionics and Software are presented, including the specific flight preparation tasks.Finally, the paper provides some highlights of the main mission results based on the interpretation of the data received via telemetry and retrieved from the flight recorders.The paper then gives some preliminary tracks of the IXV follow on, introducing the objectives of the Innovative Space Vehicle and the necessary improvements, to be developed in the frame of ISV-PRIDE.

  20. Development of an innovative validation strategy of gas-surface interaction modelling for re-entry applications

    NASA Astrophysics Data System (ADS)

    Joiner, N.; Esser, B.; Fertig, M.; Gülhan, A.; Herdrich, G.; Massuti-Ballester, B.

    2016-12-01

    This paper summarises the final synthesis of an ESA technology research programme entitled "Development of an Innovative Validation Strategy of Gas Surface Interaction Modelling for Re-entry Applications". The focus of the project was to demonstrate the correct pressure dependency of catalytic surface recombination, with an emphasis on Low Earth Orbit (LEO) re-entry conditions and thermal protection system materials. A physics-based model describing the prevalent recombination mechanisms was proposed for implementation into two CFD codes, TINA and TAU. A dedicated experimental campaign was performed to calibrate and validate the CFD model on TPS materials pertinent to the EXPERT space vehicle at a wide range of temperatures and pressures relevant to LEO. A new set of catalytic recombination data was produced that was able to improve the chosen model calibration for CVD-SiC and provide the first model calibration for the Nickel-Chromium super-alloy PM1000. The experimentally observed pressure dependency of catalytic recombination can only be reproduced by the Langmuir-Hinshelwood recombination mechanism. Due to decreasing degrees of (enthalpy and hence) dissociation with facility stagnation pressure, it was not possible to obtain catalytic recombination coefficients from the measurements at high experimental stagnation pressures. Therefore, the CFD model calibration has been improved by this activity based on the low pressure results. The results of the model calibration were applied to the existing EXPERT mission profile to examine the impact of the experimentally calibrated model at flight relevant conditions. The heat flux overshoot at the CVD-SiC/PM1000 junction on EXPERT is confirmed to produce radiative equilibrium temperatures in close proximity to the PM1000 melt temperature.This was anticipated within the margins of the vehicle design; however, due to the measurements made here for the first time at relevant temperatures for the junction, an increased

  1. An Investigation of the Re-Entry Adjustment of Indians Who Studied in the U.S.A. Occasional Papers in Intercultural Learning, Number 17.

    ERIC Educational Resources Information Center

    Hansel, Bettina

    This study explored the readjustment experience of 49 Indians who came to the United States to study and then returned to their home country. Interviews revealed that most experienced some stress or difficulty after their re-entry, with problems ranging from initial anxiety about getting a job or shock at the crowded conditions, pollution, or the…

  2. A Novel Device for True Lumen Re-Entry After Subintimal Recanalization of Superficial Femoral Arteries: First-in-Man Experience and Technical Description

    SciTech Connect

    Airoldi, Flavio Faglia, Ezio Losa, Sergio Tavano, Davide; Latib, Azeem; Mantero, Manuela Lanza, Gaetano Clerici, Giacomo

    2011-02-15

    Subintimal angioplasty (SAP) is frequently performed for the treatment of critical limb ischemia (CLI) and has been recognized as an effective technique for these patients. Nevertheless, this approach is limited by the lack of controlled re-entry into the true lumen of the target vessel. We describe a novel device for true lumen re-entry after subintimal recanalization of superficial femoral arteries (SFA). We report our experience with six patients treated between April 2009 and January 2010 with a novel system designed to facilitate true lumen re-entry. The device was advanced by ipsilateral antegrade approach through a 6-French sheath. Successful reaccess into the true lumen was obtained in five of six patients without complications. The patient in whom the reaccess to the true lumen was not possible underwent successful bypass surgery. At 30 days follow-up, the SFA was patent in all patients according to echo-Doppler examination. Our preliminary experience indicates that this novel re-entry device increases the success rate of percutaneous revascularization of chronically occluded SFA.

  3. Development, Implementation, and Validation of Supported Employment Model(s) for Traumatically Brain Injured Persons. Head Injury Re-entry Project (Project HIRe). Final Report.

    ERIC Educational Resources Information Center

    Thomas, Dale F.; Menz, Fredrick E.

    The final report of the Head Injury Re-entry Project (Project HIRe) describes activities of this 3-year (1987 to 1990) project, which used a "best practices" model approach and a community-based employment strategy with persons having traumatic brain injury (TBI) in nonurban areas. Among 15 project accomplishments are the following: (1)…

  4. Guttiferone K impedes cell cycle re-entry of quiescent prostate cancer cells via stabilization of FBXW7 and subsequent c-MYC degradation.

    PubMed

    Xi, Z; Yao, M; Li, Y; Xie, C; Holst, J; Liu, T; Cai, S; Lao, Y; Tan, H; Xu, H-X; Dong, Q

    2016-06-02

    Cell cycle re-entry by quiescent cancer cells is an important mechanism for cancer progression. While high levels of c-MYC expression are sufficient for cell cycle re-entry, the modality to block c-MYC expression, and subsequent cell cycle re-entry, is limited. Using reversible quiescence rendered by serum withdrawal or contact inhibition in PTEN(null)/p53(WT) (LNCaP) or PTEN(null)/p53(mut) (PC-3) prostate cancer cells, we have identified a compound that is able to impede cell cycle re-entry through c-MYC. Guttiferone K (GUTK) blocked resumption of DNA synthesis and preserved the cell cycle phase characteristics of quiescent cells after release from the quiescence. In vehicle-treated cells, there was a rapid increase in c-MYC protein levels upon release from the quiescence. However, this increase was inhibited in the presence of GUTK with an associated acceleration in c-MYC protein degradation. The inhibitory effect of GUTK on cell cycle re-entry was significantly reduced in cells overexpressing c-MYC. The protein level of FBXW7, a subunit of E3 ubiquitin ligase responsible for degradation of c-MYC, was reduced upon the release from the quiescence. In contrast, GUTK stabilized FBXW7 protein levels during release from the quiescence. The critical role of FBXW7 was confirmed using siRNA knockdown, which impaired the inhibitory effect of GUTK on c-MYC protein levels and cell cycle re-entry. Administration of GUTK, either in vitro prior to transplantation or in vivo, suppressed the growth of quiescent prostate cancer cell xenografts. Furthermore, elevation of FBXW7 protein levels and reduction of c-MYC protein levels were found in the xenografts of GUTK-treated compared with vehicle-treated mice. Hence, we have identified a compound that is capable of impeding cell cycle re-entry by quiescent PTEN(null)/p53(WT) and PTEN(null)/p53(mut) prostate cancer cells likely by promoting c-MYC protein degradation through stabilization of FBXW7. Its usage as a clinical modality to

  5. Uncontrolled re-entry of satellite parts after finishing their mission in LEO: Titanium alloy degradation by thermite reaction energy

    NASA Astrophysics Data System (ADS)

    Monogarov, K. A.; Pivkina, A. N.; Grishin, L. I.; Frolov, Yu. V.; Dilhan, D.

    2017-06-01

    Analytical and experimental studies conducted at Semenov Institute of Chemical Physics for investigating the use of pyrotechnic compositions, i.e., thermites, to reduce the risk of the fall of thermally stable parts of deorbiting end-of-life LEO satellites on the Earth are described. The main idea was the use of passive heating during uncontrolled re-entry to ignite thermite composition, fixed on the titanium surface, with the subsequent combustion energy release to be sufficient to perforate the titanium cover. It is supposed, that thus destructed satellite parts will lose their streamline shape, and will burn out being aerodynamically heated during further descending in atmosphere (patent FR2975080). On the base of thermodynamic calculations the most promising thermite compositions have been selected for the experimental phase. The unique test facilities have been developed for the testing of the efficiency of thermite charges to perforate the titanium TA6V cover of 0.8 mm thickness under temperature/pressure conditions duplicated the uncontrolled re-entry of titanium tank after its mission on LEO. Experiments with the programmed laser heating inside the vacuum chamber revealed the only efficient thermite composition among preliminary selected ones to be Al/Co3O4. Experimental searching of the optimal aluminum powder between spherical and flaked nano- and micron-sized ones revealed the possibility to adjust the necessary ignition delay time, according to the titanium cover temperature dependency on deorbiting time. For the titanium tank the maximum temperature is 1100 °C at altitude 68 km and pressure 60 Pa. Under these conditions Al/Co3O4 formulations with nano-Al spherical particles provide the ignition time to be 13.3 s, and ignition temperature as low as 592±5 °C, whereas compositions with the micron-sized spherical Al powder reveal these values to be much higher, i.e., 26.3 s and 869±5 °C, respectively. The analytical and experimental studies described

  6. Application of a Near Infrared Imaging System for Thermographic Imaging of the Space Shuttle during Hypersonic Re-Entry

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Tietjen, Alan B.; Horvath, Thomas J.; Tomek, Deborah M.; Gibson, David M.; Taylor, Jeff C.; Tack, Steve; Bush, Brett C.; Mercer, C. David; Shea, Edward J.

    2010-01-01

    observations confirmed the challenge of a long-range acquisition during re-entry. These challenges are due to unknown atmospheric conditions, image saturation, vibration etc. This provides the motivation for the use of a digital NIR sensor. The characterizations performed on the digital NIR sensor included radiometric, spatial, and spectral measurements using blackbody radiation sources and known targets. An assessment of the collected data for three Space Shuttle atmospheric re-entries, STS-119, STS-125, and STS-128, are provided along with a description of various events of interest captured using the digital NIR imaging system such as RCS firings and boundary layer transitions. Lastly the process used to convert the raw image counts to quantitative temperatures is presented along with comparisons to the Space Shuttle's onboard thermocouples.

  7. The application of quaternions and other spatial representations to the reconstruction of re-entry vehicle motion.

    SciTech Connect

    De Sapio, Vincent

    2010-09-01

    The analysis of spacecraft kinematics and dynamics requires an efficient scheme for spatial representation. While the representation of displacement in three dimensional Euclidean space is straightforward, orientation in three dimensions poses particular challenges. The unit quaternion provides an approach that mitigates many of the problems intrinsic in other representation approaches, including the ill-conditioning that arises from computing many successive rotations. This report focuses on the computational utility of unit quaternions and their application to the reconstruction of re-entry vehicle (RV) motion history from sensor data. To this end they will be used in conjunction with other kinematic and data processing techniques. We will present a numerical implementation for the reconstruction of RV motion solely from gyroscope and accelerometer data. This will make use of unit quaternions due to their numerical efficacy in dealing with the composition of many incremental rotations over a time series. In addition to signal processing and data conditioning procedures, algorithms for numerical quaternion-based integration of gyroscope data will be addressed, as well as accelerometer triangulation and integration to yield RV trajectory. Actual processed flight data will be presented to demonstrate the implementation of these methods.

  8. An evaluation of a resorbable (semirigid) GTR membrane in human periodontal intraosseous defects: A clinicoradiological re-entry study

    PubMed Central

    Gowda, Vinayak S.; Chava, Vijay; Kumara, Ajeya E. G.

    2011-01-01

    Aim: To evaluate the effectiveness of a resorbable, semi rigid guided tissue regeneration (GTR) membrane in the treatment of periodontal intraosseous defects. Settings and Design: Randomized controlled clinicoradiological re-entry study. Materials and Methods: Eight patients with bilateral, identical intraosseous defects were selected. The sides for test and control group were randomly allocated to treat either with bioresorbable semi rigid membrane (test group) or open flap debridement (control group). Radiographic analysis was done by comparing intraoral peri apical radiographs taken at baseline and at six months. Extended cone paralleling device with grid was used to standardize radiographs. Auto CAD software was used for the analysis. Statistical Analysis Used: Paired-t test. Results: On surgical reentry at six months, the mean reduction in depth of the defect at the test site was 2.63 mm. The mean gain in Relative attachment level was 1.75 mm. The control sites showed a statistically insignificant gain. The mean percentage defect fill assessed on radiographs using auto CAD software was 15.54%. Conclusion: The resorbable, semi-rigid GTR membrane can be effectively used for the treatment of human one-walled angular defects. PMID:22368366

  9. OPERA- A CNES Tool to Monitor Short and Middle Term Uncontrolled Re-Entries Using Mean Theories

    NASA Astrophysics Data System (ADS)

    Dolado, J. C.; Agueda, A.; Aivar, L.; Tirado, J.

    2013-09-01

    Objects in Low-Earth Orbits (LEO) and Highly Elliptical Orbits (HEO) are subjected to decay and re- entry into the atmosphere due mainly to the drag force. While being this process the best solution to avoid the proliferation of debris in space and ensure the sustainability of future space activities, it implies a threat to the population on ground. Thus, the prediction of the in-orbit lifetime of an object and the evaluation of the risk on population and ground assets constitutes a crucial task. This paper will concentrate on the first of these tasks.Unfortunately the lifetime of an object in space is remarkably difficult to predict. This is mainly due to the dependence of the atmospheric drag on a number of uncertain elements such as the density profile and its dependence on the solar activity, the atmospheric conditions, the mass and surface area of the object (very difficult to evaluate), its uncontrolled attitude, etc.In this paper we will present a method for the prediction of this lifetime based on publicly available Two-Line Elements (TLEs) from the American USSTRATCOM's Joint Space Operations Center (JSpOC). TLEs constitute an excellent source to access routinely orbital information for thousands of objects even though of their reduced and unpredictable accuracy.Additionally, the implementation of the method on a CNES's Java-based tool will be presented. This tool (OPERA) is executed routinely at CNES to predict the orbital lifetime of a whole catalogue of objects.

  10. The Use of a Re-Entry Catheter in Recanalization of Chronic Inflow Occlusions of the Common Iliac Artery

    SciTech Connect

    Ramjas, Greg; Thurley, Peter Habib, Said

    2008-05-15

    Endovascular treatment of iliac artery occlusions can be unsuccessful due to a failure to break back into the true lumen, and lesions without a proximal stump can be particularly problematic. True lumen re-entry catheters have not been previously used for this type of lesion. The authors report eight patients, five males and three females, with lifestyle-limiting intermittent claudication referred for endovascular treatment. Imaging demonstrated unilateral chronic total occlusion of the common iliac artery in six patients and two patients with short patent stumps at the origin of the occluded common iliac artery. Endovascular therapy was initially unsuccessful due to an inability to re-enter the true lumen after crossing the occlusion in the subintimal plane. With the assistance of the Outback LTD catheter it was possible to achieve continuity of the dissecting tract with the true lumen, thus facilitating successful primary stenting in all eight patients. To our knowledge this is the first report of the use of the Outback LTD catheter in this type of lesion.

  11. Specific Plasma Ionospheric Excitations Modes in the Ionosphere Produced by Space Vehicle Launch and RE Entry and Natural Phenomena

    NASA Astrophysics Data System (ADS)

    Rauscher, E. A.; van Bise, W. L.

    2001-10-01

    SPECIFIC PLASMA IONOSPHERIC EXCITATIONS MODES IN THE IONOSPHERE PRODUCED BY SPACE VEHICLE LAUNCH AND RE ENTRY AND NATURAL PHENOMENA We have examined both experimentally and theoretically the formation and excitation of highly well defined specific wave forms of plasma excitation in the D, E, F(1) and F(2) and sometimes G layers of the earth?s ionosphere. In our formal study period from October 1989 until December 1996, we measured 41 distinct events out of a possible 73 events utilizing ground based sensitive T1050 magnetometers. In five cases more than two to three stations were displayed and detected the same ionospheric excitations. Sometimes background noise was high and dominated the signals, but under good measurement conditions signals appeared to be 50 to 70 dbm over the background noise floor. Specific frequencies of the D-layer appeared around 5.2 to 6.52 Hz and E layer excitations were from 10.48 to 12.8 Hz. Sometimes an F double peak appeared around 15 to 17 Hz as excited by space shuttle activity and delta rockets and in several cases, large scale volcanism. A theoretical model has been developed which describes sustained long duration and long range coherent plasma excitation modes which occur when the ionospheric layers are shock excited. Alfven-like velocities of propogation are calculated in these ionospheric layer. Some Schumann resonates were observed from 7 to 8 Hz.

  12. A Mission Concept: Re-Entry Hopper-Aero-Space-Craft System on-Mars (REARM-Mars)

    NASA Technical Reports Server (NTRS)

    Davoodi, Faranak

    2013-01-01

    Future missions to Mars that would need a sophisticated lander, hopper, or rover could benefit from the REARM Architecture. The mission concept REARM Architecture is designed to provide unprecedented capabilities for future Mars exploration missions, including human exploration and possible sample-return missions, as a reusable lander, ascend/descend vehicle, refuelable hopper, multiple-location sample-return collector, laboratory, and a cargo system for assets and humans. These could all be possible by adding just a single customized Re-Entry-Hopper-Aero-Space-Craft System, called REARM-spacecraft, and a docking station at the Martian orbit, called REARM-dock. REARM could dramatically decrease the time and the expense required to launch new exploratory missions on Mars by making them less dependent on Earth and by reusing the assets already designed, built, and sent to Mars. REARM would introduce a new class of Mars exploration missions, which could explore much larger expanses of Mars in a much faster fashion and with much more sophisticated lab instruments. The proposed REARM architecture consists of the following subsystems: REARM-dock, REARM-spacecraft, sky-crane, secure-attached-compartment, sample-return container, agile rover, scalable orbital lab, and on-the-road robotic handymen.

  13. Use of a stent-graft and vascular occlude to treat primary and re-entry tears in a patient with a Stanford type B aortic dissection

    PubMed Central

    Shi, Huihua; Lu, Min; Jiang, Mier

    2013-01-01

    Thoracic endovascular aortic repair for aortic dissections is recognized as an effective treatment. We herein report the case of a 72-year-old male with a Stanford type B aortic dissection. A stent-graft and double-disk vascular occluder was used to repair the primary and re-entry tears, respectively. At 3 month postoperatively, computed tomographic angiography revealed no endoleaks, the stent-graft and vascular occluder to be in optimal positions, the false lumen was almost completely thrombosed, and the visceral arteries were patent. This case illustrates that it is feasible to treat re-entry tears with a vascular occluder after primary proximal stent-graft repairs. PMID:24598963

  14. ARTD1 regulates cyclin E expression and consequently cell-cycle re-entry and G1/S progression in T24 bladder carcinoma cells.

    PubMed

    Léger, Karolin; Hopp, Ann-Katrin; Fey, Monika; Hottiger, Michael O

    2016-08-02

    ADP-ribosylation is involved in a variety of biological processes, many of which are chromatin-dependent and linked to important functions during the cell cycle. However, any study on ADP-ribosylation and the cell cycle faces the problem that synchronization with chemical agents or by serum starvation and subsequent growth factor addition already activates ADP-ribosylation by itself. Here, we investigated the functional contribution of ARTD1 in cell cycle re-entry and G1/S cell cycle progression using T24 urinary bladder carcinoma cells, which synchronously re-enter the cell cycle after splitting without any additional stimuli. In synchronized cells, ARTD1 knockdown, but not inhibition of its enzymatic activity, caused specific down-regulation of cyclin E during cell cycle re-entry and G1/S progression through alterations of the chromatin composition and histone acetylation, but not of other E2F-1 target genes. Although Cdk2 formed a functional complex with the residual cyclin E, p27(Kip 1) protein levels increased in G1 upon ARTD1 knockdown most likely due to inappropriate cyclin E-Cdk2-induced phosphorylation-dependent degradation, leading to decelerated G1/S progression. These results provide evidence that ARTD1 regulates cell cycle re-entry and G1/S progression via cyclin E expression and p27(Kip 1) stability independently of its enzymatic activity, uncovering a novel cell cycle regulatory mechanism.

  15. Protective Effects of the Launch/Entry Suit (LES) and the Liquid Cooling Garment(LCG) During Re-entry and Landing After Spaceflight

    NASA Technical Reports Server (NTRS)

    Perez, Sondra A.; Charles, John B.; Fortner, G. William; Hurst, Victor, IV; Meck, Janice V.

    2002-01-01

    Heart rate and arterial pressure were measured during shuttle re-entry, landing and initial standing in crewmembers with and without inflated anti-g suits and with and without liquid cooling garments (LCG). Preflight, three measurements were obtained seated, then standing. Prior to and during re-entry, arterial pressure and heart rate were measured every five minutes until wheels stop (WS). Then crewmembers initiated three seated and three standing measurements. In subjects without inflated anti-g suits, SBP and DBP were significantly lower during preflight standing (P = 0.006; P = 0.001 respectively) and at touchdown (TD) (P = 0.001; P = 0.003 respectively); standing SBP was significantly lower after WS. on-LeG users developed significantly higher heart rates during re-entry (P = 0.029, maxG; P = 0.05, TD; P = 0.02, post-WS seated; P = 0.01, post-WS standing) than LCG users. Our data suggest that the anti-g suit is effective, but the combined anti-g suit with LCG is more effective.

  16. Infra-red and vibration tests of hybrid ablative/ceramic matrix technological breadboards for earth re-entry thermal protection systems

    NASA Astrophysics Data System (ADS)

    Barcena, Jorge; Garmendia, Iñaki; Triantou, Kostoula; Mergia, Konstatina; Perez, Beatriz; Florez, Sonia; Pinaud, Gregory; Bouilly, Jean-Marc; Fischer, Wolfgang P. P.

    2017-05-01

    A new thermal protection system for atmospheric earth re-entry is proposed. This concept combines the advantages of both reusable and ablative materials to establish a new hybrid concept with advanced capabilities. The solution consists of the design and the integration of a dual shield resulting on the overlapping of an external thin ablative layer with a Ceramic Matrix Composite (CMC) thermo-structural core. This low density ablative material covers the relatively small heat peak encountered during re-entry the CMC is not able to bear. On the other hand the big advantage of the CMC based TPS is of great benefit which can deal with the high integral heat for the bigger time period of the re-entry. To verify the solution a whole testing plan is envisaged, which as part of it includes thermal shock test by infra-red heating (heating flux up to 1 MW/m2) and vibration test under launcher conditions (Volna and Ariane 5). Sub-scale tile samples (100×100 mm2) representative of the whole system (dual ablator/ceramic layers, insulation, stand-offs) are specifically designed, assembled and tested (including the integration of thermocouples). Both the thermal and the vibration test are analysed numerically by simulation tools using Finite Element Models. The experimental results are in good agreement with the expected calculated parameters and moreover the solution is qualified according to the specified requirements.

  17. Analysis Of The ATV1 Re-Entry Using Near-UV Spectroscopic Data From The ESA/NASA Multi-Instrument Aircraft Observation Campaign

    NASA Astrophysics Data System (ADS)

    Lohle, Stefan; Marynowski, Thomas; Knapp, Andreas; Wernitz, Ricarda; Lips, Tobias

    2011-05-01

    The first Automated Transfer Vehicle (ATV1) named Jules Verne was launched in March 2009 to carry over seven tons of experiments, fuel, water, food and other supplies to the International Space Station (ISS) orbiting at about 350 km. Attached to the ISS, it served as an extension to the space station, giving extra space for the six astronauts and cosmonauts who will ultimately form the permanent ISS Crew. On September 29, 2009, a controlled de-orbit maneuver lead the spacecraft to enter the Earth's atmosphere over the south pacific ocean. The following destructive re-entry was observed by two aircraft equipped with a wide variety of imaging and spectroscopic instruments. In this paper, we present quantitative results from the near-UV spectroscopic measurements acquired aboard an experimental DC-8 aircraft operated by NASA. The wavelength range of observation allows a determination of temperatures from radiation and the investigation of atomic radiation with respect to the identification of the destructive process. Furthermore, the excitation temperatures of chromium give an insight into the explosive events occurring during re-entry. Analysing the continuum of the measured spectra, the Planck radiation temperature is fitted to the data. These temperatures indicate that most of the radiating parts are titanium alloys, i.e. the outer structure of ATV1. All results within this paper are compared to a simulated break-up scenario and related to basic results from other experimenters which allows drawing an overall scenario for this destructive re-entry.

  18. The ESA/NASA Multi-Aircraft ATV-1 Re-Entry Campaign: Analysis of Airborne Intensified Video Observations from the NASA/JSC Experiment

    NASA Technical Reports Server (NTRS)

    Barker, Ed; Maley, Paul; Mulrooney, Mark; Beaulieu, Kevin

    2009-01-01

    In September 2008, a joint ESA/NASA multi-instrument airborne observing campaign was conducted over the Southern Pacific ocean. The objective was the acquisition of data to support detailed atmospheric re-entry analysis for the first flight of the European Automated Transfer Vehicle (ATV)-1. Skilled observers were deployed aboard two aircraft which were flown at 12.8 km altitude within visible range of the ATV-1 re-entry zone. The observers operated a suite of instruments with low-light-level detection sensitivity including still cameras, high speed and 30 fps video cameras, and spectrographs. The collected data has provided valuable information regarding the dynamic time evolution of the ATV-1 re-entry fragmentation. Specifically, the data has satisfied the primary mission objective of recording the explosion of ATV-1's primary fuel tank and thereby validating predictions regarding the tanks demise and the altitude of its occurrence. Furthermore, the data contains the brightness and trajectories of several hundred ATV-1 fragments. It is the analysis of these properties, as recorded by the particular instrument set sponsored by NASA/Johnson Space Center, which we present here.

  19. The ESA/NASA Multi-Aircraft ATV-1 Re-Entry Campaign: Analysis of Airborne Intensified Video Observations from the NASA/JSC Experiment

    NASA Technical Reports Server (NTRS)

    Barker, Ed; Maley, Paul; Mulrooney, Mark; Beaulieu, Kevin

    2009-01-01

    In September 2008, a joint ESA/NASA multi-instrument airborne observing campaign was conducted over the Southern Pacific ocean. The objective was the acquisition of data to support detailed atmospheric re-entry analysis for the first flight of the European Automated Transfer Vehicle (ATV)-1. Skilled observers were deployed aboard two aircraft which were flown at 12.8 km altitude within visible range of the ATV-1 re-entry zone. The observers operated a suite of instruments with low-light-level detection sensitivity including still cameras, high speed and 30 fps video cameras, and spectrographs. The collected data has provided valuable information regarding the dynamic time evolution of the ATV-1 re-entry fragmentation. Specifically, the data has satisfied the primary mission objective of recording the explosion of ATV-1's primary fuel tank and thereby validating predictions regarding the tanks demise and the altitude of its occurrence. Furthermore, the data contains the brightness and trajectories of several hundred ATV-1 fragments. It is the analysis of these properties, as recorded by the particular instrument set sponsored by NASA/Johnson Space Center, which we present here.

  20. Angular and Linear Velocity Estimation for a Re-Entry Vehicle Using Six Distributed Accelerometers: Theory, Simulation and Feasibility

    SciTech Connect

    Clark, G

    2003-04-28

    This report describes a feasibility study. We are interested in calculating the angular and linear velocities of a re-entry vehicle using six acceleration signals from a distributed accelerometer inertial measurement unit (DAIMU). Earlier work showed that angular and linear velocity calculation using classic nonlinear ordinary differential equation (ODE) solvers is not practically feasible, due to mathematical and numerical difficulties. This report demonstrates the theoretical feasibility of using model-based nonlinear state estimation techniques to obtain the angular and linear velocities in this problem. Practical numerical and calibration issues require additional work to resolve. We show that the six accelerometers in the DAIMU are not sufficient to provide observability, so additional measurements of the system states are required (e.g. from a Global Positioning System (GPS) unit). Given the constraint that our system cannot use GPS, we propose using the existing on-board 3-axis magnetometer to measure angular velocity. We further show that the six nonlinear ODE's for the vehicle kinematics can be decoupled into three ODE's in the angular velocity and three ODE's in the linear velocity. This allows us to formulate a three-state Gauss-Markov system model for the angular velocities, using the magnetometer signals in the measurement model. This re-formulated model is observable, allowing us to build an Extended Kalman Filter (EKF) for estimating the angular velocities. Given the angular velocity estimates from the EKF, the three ODE's for the linear velocity become algebraic, and the linear velocity can be calculated by numerical integration. Thus, we do not need direct measurements of the linear velocity to provide observability, and the technique is mathematically feasible. Using a simulation example, we show that the estimator adds value over the numerical ODE solver in the presence of measurement noise. Calculating the velocities in the presence of

  1. Factors associated with dropout among patients in opioid maintenance treatment (OMT) and predictors of re-entry. A national registry-based study.

    PubMed

    Bukten, Anne; Skurtveit, Svetlana; Waal, Helge; Clausen, Thomas

    2014-10-01

    Retention in treatment is often highlighted as one of the key indicators of success in opioid maintenance treatment (OMT). To identify factors associated with long-term retention in opioid maintenance treatment and to analyse predictors of subsequent treatment episodes. Treatment retention and re-entry were examined for a national cohort of patients admitted to OMT in Norway in the period 1997-2003. Multivariate Cox regression models were used to investigate factors associated with treatment dropout 18months after treatment entry. The 18month retention rate among patients admitted to OMT in Norway (n=2431) was 65.8% (n=1599). Dropout from OMT within 18months was associated with younger age (HR 0.97 [0.96-0.98]), high levels of general pre-treatment criminal offences (HR 1.66 [1.32-2.09]) and having drug-related offences during the 30days prior to dropout (HR 1.80 [1.36-2.38]). Of the patients who dropped out (n=832), 42.7% (n=355) were re-engaged in subsequent treatment episodes. Pre-treatment criminal offences were associated with increased odds for treatment re-entry, whereas being younger and having drug-related offences during the first OMT episode were associated with lower odds for re-engagement in OMT. Gender was not associated with treatment dropout and re-entry. High levels of pre-treatment criminal offences and drug offences during the 30days prior to dropout were associated with treatment dropout. Efforts to increase support services to these patients may contribute to higher rates of retention in OMT. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. The use of a Colapinto TIPS Needle under cone-beam computed tomography guidance for true lumen re-entry in subintimal recanalization of chronic iliac artery occlusion.

    PubMed

    Liang, Huei-Lung; Li, Ming-Feng; Chiang, Chia-Ling; Chen, Matt Chiung-Yu; Wu, Chieh-Jen; Pan, Huay-Ben

    2017-06-01

    To report the technique and clinical outcome of subintimal re-entry in chronic iliac artery occlusion by using a Colapinto transjugular intrahepatic portosystemic shunt (TIPS) needle under rotational angiography (cone-beam computed tomography; CT) imaging guidance. Patients with chronic iliac artery occlusion with earlier failed attempts at conventional percutaneous recanalization during the past 5 years were enrolled in our study. In these patients, an ipsilateral femoral access route was routinely utilized in a retrograde fashion. A Colapinto TIPS Needle was used to aid the true lumen re-entry after failed conventional intraluminal or subintimal guidewire and catheter-based techniques. The puncture was directed under rotational angiography cone-beam CT guidance to re-enter the abdominal aorta. Bare metallic stents 8-10 mm in diameter were deployed in the common iliac artery, and followed by balloon dilation. Ten patients (9 male; median age, 75 years) were included in our investigation. The average occlusion length was 10.2 cm (range, 4-15 cm). According to the Trans-Atlantic Inter-Society Consensus (TASC) II classification, there were five patients each with Class B and D lesions. Successful re-entry was achieved in all patients without procedure-related complications. The ankle-brachial index (ABI) values increased from 0.38-0.79 to 0.75-1.28 after the procedure. Imaging follow-up (> 6 months) was available in six patients with patency of all stented iliac artery. Thereafter, no complaints of recurrent clinical symptoms occurred during the follow-up period. The use of Colapinto TIPS needle, especially under cone-beam CT image guidance, appears to be safe and effective to re-enter the true lumen in a subintimal angioplasty for a difficult chronic total iliac occlusion. Copyright © 2017. Published by Elsevier Taiwan LLC.

  3. Attenuation of low-frequency electromagnetic wave in the thin sheath enveloping a high-speed vehicle upon re-entry

    NASA Astrophysics Data System (ADS)

    Liu, DongLin; Li, XiaoPing; Liu, YanMing; Xie, Kai; Bai, BoWen

    2017-02-01

    Low-frequency (LF) electromagnetic (EM) waves are suggested as potentially solving "radio blackout" caused by a plasma sheath enveloping a high-speed vehicle on re-entry. However, the traditional plasma absorption theory neglects the fact that the plasma sheath is electrically small compared to LF EM wavelengths. To understand clearly the attenuation of such waves through the plasma sheath, different attenuation mechanisms for the electric field (SE) and magnetic field (SH) were studied using the equivalent circuit approach. Analytical expressions were derived by modeling the plasma sheath as a spherical shell, and numerical simulations were performed to validate the effectiveness of the expressions. SE and SH are calculated for various plasma parameter settings; the EM wave attenuations obtained from plasma absorption theory are used for comparison. Results show that, instead of SE and SH being equal in the plasma absorption theory, SE and SH are no longer the same for electrically small sizes. Whereas |SH| is close to that from plasma absorption theory, |SE| is much higher. Further analysis shows that |SH| is a function of the ratio of electron density (ne) and collision frequency (ve) and increases with increasing ne/ve. Numerical simulations with radio-attenuation-measurement-C-like vehicle's plasma sheath parameters are performed and the results show that the magnetic field attenuation in the front part of the vehicle is much lower than in the rear. So it is suggested to place the magnetic loop antenna in the very front part of the vehicle. Finally, SH at different frequencies are calculated using plasma sheath parameter values simulating the re-entry phase of a radio-attenuation measurement-C vehicle and results show that such a vehicle might overcome radio blackout during the entire re-entry phase if systems operating below 3 MHz and above the L-band are combined with a lower-frequency system working below Earth's ionosphere and a higher-frequency system

  4. Facilitation of school re-entry and peer acceptance of children with cancer: a review and meta-analysis of intervention studies.

    PubMed

    Helms, A S; Schmiegelow, K; Brok, J; Johansen, C; Thorsteinsson, T; Simovska, V; Larsen, H B

    2016-01-01

    Increased survival rates from childhood cancer call for efforts to reintegrate children with cancer back into their academic and social environments. The aims of this study were to: (1) review and analyse the existing literature on school re-entry interventions for children with cancer; and (2) discuss the importance of peer involvement in the treatment. Relevant databases were searched using equivalent search algorithms and six studies were selected that target children with cancer and/or their classmates. Two authors independently reviewed the literature for data extraction. The articles were reviewed using the PRISMA model for reporting reviews. Statistical calculations for the meta-analyses were done using Review Manager 5.2. The meta-analyses showed significant effects of school re-entry programmes in terms of enhancing academic achievement in children with cancer (P = 0.008) and lowering their levels of depression (P = 0.05). Increased knowledge among classmates was associated with less fear and a more positive attitude towards the child with cancer. Due to limited numbers of patients, lack of control groups, and the diversity of intervention strategies used in previous studies, there is a need for intervention programmes exploring the optimal path for the reintegration of children with cancer into the education system and into their peer groups. © 2014 John Wiley & Sons Ltd.

  5. Autogenic-Feedback Training Exercise (AFTE) Mitigates the Effects of Spatial Disorientation to Simulated Orion Spacecraft Re-Entry: Individual Differences

    NASA Technical Reports Server (NTRS)

    Cowings, Patricia S.; Toscano, William B.; Reschke, Millard F.; Gebreyesus, Fiyori; Rocha, Christopher

    2017-01-01

    NASA has identified a potential risk of spatial disorientation to future astronauts during re-entry of the proposed Orion spacecraft. The purpose of this study was to determine if a 6-hour physiological training procedure, Autogenic-Feedback Training Exercise (AFTE), can mitigate these effects. Twenty subjects were assigned to two groups (AFTE and Control) matched for motion sickness susceptibility and gender. All subjects received a standard rotating chair test to determine motion sickness susceptibility; three training sessions on a manual performance task; and four exposures to a simulated Orion re-entry test in the rotating chair. Treatment subjects were given two hours of AFTE training before each Orion test. A diagnostic scale was used to evaluate motion sickness symptom severity. Results showed that 2 hours of AFTE significantly reduced motion sickness symptoms during the second Orion test. AFTE subjects were able to maintain lower heart rates and skin conductance levels and other responses than the control group subjects during subsequent tests. Trends show that performance was less degraded for AFTE subjects. The results of this study indicate that astronauts could benefit from receiving at least 2 hours of preflight AFTE. In addition, flight crews could benefit further by practicing physiologic self-regulation using mobile devices.

  6. Numerical and experimental study of the thermal degradation process during the atmospheric re-entry of a TiAl6V4 tank

    NASA Astrophysics Data System (ADS)

    Prévereaud, Y.; Vérant, J.-L.; Balat-Pichelin, M.; Moschetta, J.-M.

    2016-05-01

    To answer the question of space debris survivability during atmospheric entry ONERA uses its software named MUSIC/FAST. So, the first part of this paper is dedicated to the presentation of the ONERA tool and its validation by comparison with flight data and CFD computations. However, the influence of oxidation on the thermal degradation process and material properties in atmospheric entry conditions is still unknown. A second step is then devoted to the presentation of an experimental campaign investigating TA6V oxidation in atmospheric entry conditions, as the most of the debris found on ground are made of this material. Experiments have been realized using the MESOX facility implemented at the 6 kW solar furnace in PROMES-CNRS laboratory. Finally, an application of MUSIC/FAST is proposed on the atmospheric re-entry of a generic TA6V tank. Aiming at degradation assessment, a sensitive study to initial conditions is conducted. To complete computational analysis regarding degradation process by melting, a numerical analysis of the influence of oxidation on the thermal wall degradation during the tank atmospheric re-entry is presented as well.

  7. African American Female Offender’s Use of Alternative and Traditional Health Services After Re-Entry: Examining the Behavioral Model for Vulnerable Populations

    PubMed Central

    Oser, Carrie B.; Bunting, Amanda M.; Pullen, Erin; Stevens-Watkins, Danelle

    2016-01-01

    This is the first known study to use the Gelberg-Andersen Behavioral Model for Vulnerable Populations to predict African American women’s use of three types of health services (alternative, hospitalization, and ambulatory) in the 18 months after release from prison. In the multivariate models, the most robust predictors of all three types of service utilization were in the vulnerable theoretical domains. Alternative health services were predicted by ethnic community membership, higher religiosity, and HIV/HCV. Hospitalizations were predicted by the lack of barriers to health care and disability. Ambulatory office visits were predicted by more experiences of gendered racism, a greater number of physical health problems, and HIV/HCV. Findings highlight the importance of cultural factors and HIV/HCV in obtaining both alternative and formal health care during community re-entry. Clinicians and policy makers should consider the salient role that the vulnerable domain plays in offender’s accessing health services. PMID:27133515

  8. Surgical re-entry evaluation of regenerative efficacy of bioactive Gengigel® and platelet-rich fibrin in the treatment of grade II furcation: A novel approach

    PubMed Central

    Sandhu, Gurkirat Kaur; Khinda, Paramjit Kaur; Gill, Amarjit Singh; Kalra, Harveen Singh

    2015-01-01

    The furcation area creates situations in which routine periodontal procedures are somewhat limited, and surgical procedures are generally required. The introduction of bioactive agents, such as platelet concentrates, enamel matrix derivatives, bone morphogenic proteins, and matrix macromolecules such as hyaluronic acid has expanded the scope for better outcomes in furcation treatment. Hyaluronic acid is a naturally occurring nonsulfated high molecular weight glycosaminoglycan that forms a critical component of the extracellular matrix and contributes significantly to tissue hydrodynamics, cell migration, and proliferation. Platelet-rich fibrin (PRF) is an immune and platelet concentrate containing all the constituents of a blood sample, which are favorable for healing and immunity. The purpose of the present case report was to assess through surgical re-entry, the regenerative capacity of Gengigel® in conjunction with PRF in a patient with grade II furcation defect. It was observed that the combined approach resulted in significant furcation defect fill on re-evaluation at 6 months. PMID:26681869

  9. Time Since Release from Incarceration and HIV Risk Behaviors Among Women: The Potential Protective Role of Committed Partners During Re-entry.

    PubMed

    Hearn, Lauren E; Whitehead, Nicole Ennis; Khan, Maria R; Latimer, William W

    2015-06-01

    After release from incarceration, former female inmates face considerable stressors, which may influence drug use and other risk behaviors that increase risk for HIV infection. Involvement in a committed partnership may protect women against re-entry stressors that may lead to risky behaviors. This study measured the association between time since release from incarceration (1-6 months ago, and >6 months ago versus never incarcerated) and HIV risk behaviors and evaluated whether these associations differed by involvement in a committed partnership. Women released within the past 6 months were significantly more likely to have smoked crack cocaine, used injection drugs and engaged in transactional sex in the past month compared to never-incarcerated women and women released more distally. Stratified analyses indicated that incarceration within the past 6 months was associated with crack cocaine smoking, injection drug use and transactional sex among women without a committed partner yet unassociated with these risk behaviors among those with a committed partner.

  10. Financial Aid: Helping Re-entry Women Pay College Costs: What Institutions Can Do to Provide Financial Resources to Women Re-entering the Educational System. Field Evaluation Draft.

    ERIC Educational Resources Information Center

    Dunkle, Margaret C.

    Problems and barriers to financial aid that commonly face women re-entering the educational system are identified, and ways in which higher education institutions can be more responsive to the financial needs of re-entry women students are suggested. A wide range of possible actions are identified so that institutions can pursue those most…

  11. Implications of the Turing completeness of reaction-diffusion models, informed by GPGPU simulations on an XBox 360: cardiac arrhythmias, re-entry and the Halting problem.

    PubMed

    Scarle, Simon

    2009-08-01

    In the arsenal of tools that a computational modeller can bring to bare on the study of cardiac arrhythmias, the most widely used and arguably the most successful is that of an excitable medium, a special case of a reaction-diffusion model. These are used to simulate the internal chemical reactions of a cardiac cell and the diffusion of their membrane voltages. Via a number of different methodologies it has previously been shown that reaction-diffusion systems are at multiple levels Turing complete. That is, they are capable of computation in the same manner as a universal Turing machine. However, all such computational systems are subject to a limitation known as the Halting problem. By constructing a universal logic gate using a cardiac cell model, we highlight how the Halting problem therefore could limit what it is possible to predict about cardiac tissue, arrhythmias and re-entry. All simulations for this work were carried out on the GPU of an XBox 360 development console, and we also highlight the great gains in computational power and efficiency produced by such general purpose processing on a GPU for cardiac simulations.

  12. Treatment of a large periradicular defect using guided tissue regeneration: A case report of 2 years follow-up and surgical re-entry.

    PubMed

    Gurav, Abhijit Ningappa; Shete, Abhijeet Rajendra; Naiktari, Ritam

    2015-01-01

    Periradicular (PR) bone defects are common sequelae of chronic endodontic lesions. Sometimes, conventional root canal therapy is not adequate for complete resolution of the lesion. PR surgeries may be warranted in such selected cases. PR surgery provides a ready access for the removal of pathologic tissue from the periapical region, assisting in healing. Recently, the regeneration of the destroyed PR tissues has gained more attention rather than repair. In order to promote regeneration after apical surgery, the principle of guided tissue regeneration (GTR) has proved to be useful. This case presents the management of a large PR lesion in a 42-year-old male subject. The PR lesion associated with 21, 11 and 12 was treated using GTR membrane, fixated with titanium minipins. The case was followed up for 2 years radiographically, and a surgical re-entry confirmed the re-establishment of the lost labial plate. Thus, the principle of GTR may immensely improve the clinical outcome and prognosis of an endodontically involved tooth with a large PR defect.

  13. Treatment of a large periradicular defect using guided tissue regeneration: A case report of 2 years follow-up and surgical re-entry

    PubMed Central

    Gurav, Abhijit Ningappa; Shete, Abhijeet Rajendra; Naiktari, Ritam

    2015-01-01

    Periradicular (PR) bone defects are common sequelae of chronic endodontic lesions. Sometimes, conventional root canal therapy is not adequate for complete resolution of the lesion. PR surgeries may be warranted in such selected cases. PR surgery provides a ready access for the removal of pathologic tissue from the periapical region, assisting in healing. Recently, the regeneration of the destroyed PR tissues has gained more attention rather than repair. In order to promote regeneration after apical surgery, the principle of guided tissue regeneration (GTR) has proved to be useful. This case presents the management of a large PR lesion in a 42-year-old male subject. The PR lesion associated with 21, 11 and 12 was treated using GTR membrane, fixated with titanium minipins. The case was followed up for 2 years radiographically, and a surgical re-entry confirmed the re-establishment of the lost labial plate. Thus, the principle of GTR may immensely improve the clinical outcome and prognosis of an endodontically involved tooth with a large PR defect. PMID:26941526

  14. Propagation of normal beats and re-entry in a computational model of ventricular cardiac tissue with regional differences in action potential shape and duration.

    PubMed

    Clayton, Richard H; Holden, Arun V

    2004-01-01

    There is substantial experimental evidence from studies using both intact tissue and isolated single cells to support the existence of different cell types within the ventricular wall of the heart, each possessing different electrical properties. However other studies have failed to find these differences, and instead support the idea that electrical coupling in vivo between regions with different cell types smoothes out differences in action potential shape and duration. In this study we have used a computational model of electrical activation in heterogenous 2D and 3D cardiac tissue to investigate the propagation of both normal beats and arrhythmias. We used the Luo-Rudy dynamic model for guinea pig ventricular cells, with simplified Ca2+ handling and transmural heterogeneity in IKs and Ito. With normal cell-to-cell coupling, a layer of M cells was not necessary for the formation of an upright T wave in the simulated electrocardiogram, and the amplitude and configuration of the T wave was not greatly affected by the thickness and configuration of the M cell layer. Transmural gradients in repolarisation pushed re-entrant waves with an intramural filament towards either the base or the apex of the ventricles, and caused transient break up of re-entry with a transmural filament. Copyright 2004 Elsevier Ltd.

  15. Re-Entry and Simulation,

    DTIC Science & Technology

    1983-11-09

    will accelerate the combustion and erosion of the warhead. Another problem, which is. not considered as an obstacle, is the creation of the so-called...only * cagiable of simulating the high spoal co4itift of up to a x lnoMbet obove 20, but also abl, to imuatO tbe Wit, altitude, ocAiticns furing the

  16. Evaluation of Gengigel® Application in the Management of Furcation with Coronally Advanced Flap through Surgical Re-Entry-A Split Mouth Clinical Study

    PubMed Central

    Gupta, Sugandha; Kediege, Suresh D; Gupta, Akanksha

    2017-01-01

    Introduction One of the challenging and unique periodontal problem of Grade II furcation defect has been managed through different treatment modalities in the past. A successful approach is based on complete closure of the defect. Different regenerative approaches have been tried. Aim This study was carried out with an aim to evaluate the role of Gengigel® (0.8% hyaluronic acid) as a potential material for regeneration of lost attachment apparatus. Materials and Methods A total of 20 sites with Grade II furcation defects from 10 patients were selected using random sampling technique. These were divided into Group A (placement of hyaluronic acid) and Group B (without placement of hyaluronic acid) according to treatment modality. Furcation defect assessment was done in vertical and horizontal depth preoperatively and postoperatively at six months through surgical re-entry. Recorded data was subjected to the statistical analysis unpaired and paired t-tests for intergroup and intragroup comparisons respectively. Results Mean plaque index, gingival index and bleeding index score showed statistically highly significant and significant results respectively, for both the groups at baseline and six months. Mean difference in probing pocket depth and Relative Attachment Level (RAL) were statistically highly significant, whereas, mean difference of gingival position margin was non significant for both the groups, at baseline and six months. Mean difference in horizontal component at baseline and six months was statistically highly significant for both the groups. Mean difference in vertical component at baseline and six months was statistically significant for both the groups. On comparison, the mean difference in vertical and horizontal component of Group A and Group B at six months was statistically not significant. conclusion Both Gengigel® with coronally positioned flap and coronally positioned flap alone are effective in the treatment of Grade II furcation defects. The

  17. Long-term outcomes with use of the CrossBoss and stingray coronary CTO crossing and re-entry devices.

    PubMed

    Mogabgab, Owen; Patel, Vishal G; Michael, Tesfaldet T; Fuh, Eric; Alomar, Mohammed; Rangan, Bavana V; Abdullah, Shuaib M; Banerjee, Subhash; Brilakis, Emmanouil S

    2013-11-01

    The Boston Scientific CrossBoss and Stingray Coronary CTO Crossing and Re-Entry devices (formerly the BridgePoint Medical System) can improve success rates in chronic total occlusion (CTO) percutaneous coronary intervention (PCI), but there are no published data on long-term clinical outcomes. The acute and long-term outcomes of 170 consecutive patients who underwent CTO PCI at our institution were reviewed, including 60 patients in whom the CrossBoss and Stingray devices were used and 110 patients treated with other crossing strategies. Baseline characteristics were similar between the two cohorts. Patients in whom the CrossBoss/Stingray was utilized had more prior CTO PCI attempts (13.1% vs 1.6%; P=.003), required longer fluoroscopy times (46 ± 22 minutes vs 35 ± 20 minutes; P<.001), higher contrast dose (390 ± 141 mL vs 323 ± 132 mL; P>.99), and more guidewires for lesion crossing (8.0 ± 6.5 vs 4.7 ± 2.3; P<.001), but procedural success (75.8% vs 76.2%; P>.99) and major complication rates (4.8% vs 3.2%; P=.69) were similar. During a median follow-up of 1.81 years, the CrossBoss/Stingray group had no difference in target lesion revascularization (40.9% vs 29.6%; P=.13) and major adverse clinical events (40.3% vs 35.2%; P=.42). Use of the CrossBoss/Stingray devices for CTO PCI is associated with equally high success and equally low complication rates as other techniques, both immediately post procedure and during long-term follow-up, in spite of its use in higher complexity cases.

  18. Spectroscopic Observation of the Stardust Re-Entry in the Near UV with SLIT: Deduction of Surface Temperatures and Plasma Radiation

    NASA Technical Reports Server (NTRS)

    Winter, Michael W.; Trumble, Kerry A.

    2010-01-01

    Thermal radiation of the heat-shield and the emission of the post-shock layer around the Stardust capsule, during its re-entry, were detected by a NASA-led observation campaign aboard NASA's DC-8 airborne observatory involving teams from several nations. The German SLIT experiment used a conventional spectrometer, in a Czerny-Turner configuration (300 mm focal length and a 600 lines/mm grating), fed by fiber optics, to cover a wavelength range from 324 nm to 456 nm with a pixel resolution of 0.08 nm. The reentering spacecraft was tracked m uansuinaglly a camera with a view angle of 20 degrees, and light from the capsule was collected using a small mirror telescope with a view angle of only 0.45 degrees. Data were gathered with a measurement frequency of 5 Hz in a 30-second time interval around the point of maximum heating until the capsule left the field of view. The emission of CN (as a major ablation product), N2(+) and different atoms were monitored successfully during that time. Due to the nature of the experimental set up, spatial resolution of the radiation field was not possible. Therefore, all measured values represent an integration of radiation from the visible part of the glowing heat shield, and from the plasma in the post-shock region. Further, due to challenges in tracking not every spectrum gathered contained data. The measured spectra can be split up into two parts: (i) continuum spectra which represent a superposition of the heat shield radiation and the continuum radiation of potential dust particles in the plasma, and (ii) line spectra from the plasma in the shock layer. Planck temperatures (interpreted as the surface temperatures of the Stardust heat shield) were determined assuming either a constant surface temperature, or a temperature distribution deduced from numerical simulation. The constant surface temperatures are in good agreement with numerical simulations, but the peak values at the stagnation point are significantly lower than those

  19. Fad24, a Positive Regulator of Adipogenesis, Is Required for S Phase Re-entry of C2C12 Myoblasts Arrested in G0 Phase and Involved in p27(Kip1) Expression at the Protein Level.

    PubMed

    Ochiai, Natsuki; Nishizuka, Makoto; Osada, Shigehiro; Imagawa, Masayoshi

    2016-05-01

    Factor for adipocyte differentiation 24 (fad24) is a positive regulator of adipogenesis. We previously found that human fad24 is abundantly expressed in skeletal muscle. However, the function of fad24 in skeletal muscle remains largely unknown. Because skeletal muscle is a highly regenerative tissue, we focused on the function of fad24 in skeletal muscle regeneration. In this paper, we investigated the role of fad24 in the cell cycle re-entry of quiescent C2C12 myoblasts-mimicked satellite cells. The expression levels of fad24 and histone acetyltransferase binding to ORC1 (hbo1), a FAD24-interacting factor, were elevated at the early phase of the regeneration process in response to cardiotoxin-induced muscle injury. The knockdown of fad24 inhibited the proliferation of quiescent myoblasts, whereas fad24 knockdown did not affect differentiation. S phase entry following serum activation is abrogated by fad24 knockdown in quiescent cells. Furthermore, fad24 knockdown cells show a marked accumulation of p27(Kip1) protein. These results suggest that fad24 may have an important role in the S phase re-entry of quiescent C2C12 cells through the regulation of p27(Kip1) at the protein level.

  20. Initial Experience and Feasibility of the New Low-Profile Stingray Catheter as Part of the Antegrade Dissection and Re-Entry Revascularization Strategy for Coronary Chronic Total Occlusions

    PubMed Central

    Maeremans, Joren; Palmers, Pieter-Jan; Dens, Joseph

    2017-01-01

    Case series Patient: Male, 77 • Male, 57 • Male, 73 Final Diagnosis: Coronary chronic total occlusion Symptoms: Angina pectoris Medication: — Clinical Procedure: Percutaneous coronary intervention of coronary chronic total occlusions Specialty: Cardiology Objective: Unusual setting of medical care Background: During antegrade dissection re-entry (ADR) of chronic total occlusions (CTO), the first-generation Stingray catheter requires the use of large-bore guides (sheathless 7.5 Fr or 8 Fr), which increases the risk for access site-related complications and compromises radial approaches. Smaller guiding sizes necessitate long guidewires (e.g., 300 cm) or guidewire extensions for catheter advancement or removal. However, friction between guides and the Stingray catheter can result in unstable guidewire position or unintentional removal. Furthermore, failure to deliver the catheter at the distal re-entry zone is a common problem. To overcome issues of deliverability and reduce the need for pre-dilatations, with its inherent risk of creating subintimal hematomas, the Stingray low-profile (LP) balloon catheter was developed. Case Report: We describe 3 cases of successful application of the novel Stingray LP catheter during ADR. In all cases, 7 Fr guiding catheters were successfully used in combination with the device. The lower profile facilitated a good exchange and delivery of the device, without the need for balloon pre-dilatations in 2 cases. This resulted in a limited subintimal plane, enabling a smooth puncture into the true lumen. One case presented with extreme levels of calcification and tortuosity, resulting in a high degree of friction, despite the lower catheter profile. No in-hospital coronary or access site-related complications occurred. Conclusions: This case report illustrates the feasibility of the Stingray LP catheter for the treatment of CTOs via the ADR technique. The lower profile of the catheter potentially increases the deliverability

  1. Clinical evaluation of regenerative potential of type I collagen membrane along with xenogenic bone graft in the treatment of periodontal intrabony defects assessed with surgical re-entry and radiographic linear and densitometric analysis

    PubMed Central

    Sowmya, N. K.; Tarun Kumar, A. B.; Mehta, D. S.

    2010-01-01

    Background and Objectives: The primary goal of periodontal therapy is to restore the tooth supporting tissues lost due to periodontal disease. The aim of the present study was to compare the efficacy of combination of type I collagen (GTR membrane) and xenogenic bone graft with open flap debridement (OFD) in treatment of periodontal intrabony defects. Materials and Methods: Twenty paired intrabony defects were surgically treated using split mouth design. The defects were randomly assigned to treatment with OFD + collagen membrane + bone graft (Test) or OFD alone (Control). The clinical efficacy of two treatment modalities was evaluated at 9 month postoperatively by clinical, radiographical, and intrasurgical (re-entry) parameters. The measurements included probing pocket depth (PD), clinical attachment level (CAL), gingival recession (GR), bone fill (BF), bone density (BD) and intra bony component (INTRA). Results: The mean reduction in PD at 0–9 month was 3.3±0.82 mm and CAL gain of 3.40±1.51 mm occurred in the collagen membrane + bone graft (Test) group; corresponding values for OFD (Control) were 2.20±0.63 mm and 1.90±0.57 mm. Similar pattern of improvement was observed when radiographical and intra-surgical (re-entry) post operative evaluation was made. All improvement in different parameters was statistically significant (P< 0.01). Interpretation and Conclusion: Treatment with a combination of collagen membrane and bone graft led to a significantly more favorable clinical outcome in intrabony defects as compared to OFD alone. PMID:20922075

  2. Initial Experience and Feasibility of the New Low-Profile Stingray Catheter as Part of the Antegrade Dissection and Re-Entry Revascularization Strategy for Coronary Chronic Total Occlusions.

    PubMed

    Maeremans, Joren; Palmers, Pieter-Jan; Dens, Joseph

    2017-01-31

    BACKGROUND During antegrade dissection re-entry (ADR) of chronic total occlusions (CTO), the first-generation Stingray catheter requires the use of large-bore guides (sheathless 7.5 Fr or 8 Fr), which increases the risk for access site-related complications and compromises radial approaches. Smaller guiding sizes necessitate long guidewires (e.g., 300 cm) or guidewire extensions for catheter advancement or removal. However, friction between guides and the Stingray catheter can result in unstable guidewire position or unintentional removal. Furthermore, failure to deliver the catheter at the distal re-entry zone is a common problem. To overcome issues of deliverability and reduce the need for pre-dilatations, with its inherent risk of creating subintimal hematomas, the Stingray low-profile (LP) balloon catheter was developed. CASE REPORT We describe 3 cases of successful application of the novel Stingray LP catheter during ADR. In all cases, 7 Fr guiding catheters were successfully used in combination with the device. The lower profile facilitated a good exchange and delivery of the device, without the need for balloon pre-dilatations in 2 cases. This resulted in a limited subintimal plane, enabling a smooth puncture into the true lumen. One case presented with extreme levels of calcification and tortuosity, resulting in a high degree of friction, despite the lower catheter profile. No in-hospital coronary or access site-related complications occurred. CONCLUSIONS This case report illustrates the feasibility of the Stingray LP catheter for the treatment of CTOs via the ADR technique. The lower profile of the catheter potentially increases the deliverability, safety, and exchangeability of the device.

  3. The endocrine dyscrasia that accompanies menopause and andropause induces aberrant cell cycle signaling that triggers re-entry of post-mitotic neurons into the cell cycle, neurodysfunction, neurodegeneration and cognitive disease.

    PubMed

    Atwood, Craig S; Bowen, Richard L

    2015-11-01

    This article is part of a Special Issue "SBN 2014". Sex hormones are physiological factors that promote neurogenesis during embryonic and fetal development. During childhood and adulthood these hormones support the maintenance of brain structure and function via neurogenesis and the formation of dendritic spines, axons and synapses required for the capture, processing and retrieval of information (memories). Not surprisingly, changes in these reproductive hormones that occur with menopause and during andropause are strongly correlated with neurodegeneration and cognitive decline. In this connection, much evidence now indicates that Alzheimer's disease (AD) involves aberrant re-entry of post-mitotic neurons into the cell cycle. Cell cycle abnormalities appear very early in the disease, prior to the appearance of plaques and tangles, and explain the biochemical, neuropathological and cognitive changes observed with disease progression. Intriguingly, a recent animal study has demonstrated that induction of adult neurogenesis results in the loss of previously encoded memories while decreasing neurogenesis after memory formation during infancy mitigated forgetting. Here we review the biochemical, epidemiological and clinical evidence that alterations in sex hormone signaling associated with menopause and andropause drive the aberrant re-entry of post-mitotic neurons into an abortive cell cycle that leads to neurite retraction, neuron dysfunction and neuron death. When the reproductive axis is in balance, gonadotropins such as luteinizing hormone (LH), and its fetal homolog, human chorionic gonadotropin (hCG), promote pluripotent human and totipotent murine embryonic stem cell and neuron proliferation. However, strong evidence supports menopausal/andropausal elevations in the LH:sex steroid ratio as driving aberrant mitotic events. These include the upregulation of tumor necrosis factor; amyloid-β precursor protein processing towards the production of mitogenic Aβ; and

  4. Disruption of the nuclear membrane by perinuclear inclusions of mutant huntingtin causes cell-cycle re-entry and striatal cell death in mouse and cell models of Huntington's disease

    PubMed Central

    Liu, Kuan-Yu; Shyu, Yu-Chiau; Barbaro, Brett A.; Lin, Yuan-Ta; Chern, Yijuang; Thompson, Leslie Michels; James Shen, Che-Kun; Marsh, J. Lawrence

    2015-01-01

    Accumulation of N-terminal fragments of mutant huntingtin (mHTT) in the cytoplasm, nuclei and axons of neurons is a hallmark of Huntington's disease (HD), although how these fragments negatively impact neurons remains unclear. We followed the distribution of mHTT in the striata of transgenic R6/2-J2 HD mice as their motor function declined. The fraction of cells with diffuse, perinuclear or intranuclear mHTT changed in parallel with decreasing motor function. In transgenic mice, medium spiny neurons (MSNs) that exhibited perinuclear inclusions expressed cell-cycle markers typically not seen in the striata of normal mice, and these cells are preferentially lost as disease progresses. Electron microscopy reveals that perinuclear inclusions disrupt the nuclear envelope. The progression of perinuclear inclusions being accompanied by cell-cycle activation and culminating in cell death was also observed in 1° cortical neurons. These observations provide a strong correlation between the subcellular location of mHTT, disruption of the nucleus, re-entry into the cell-cycle and eventual neuronal death. They also highlight the fact that the subcellular distribution of mHTT is highly dynamic such that the distribution of mHTT observed depends greatly on the stage of the disease being examined. PMID:25398943

  5. UARS Re-Entry Prediction and Analysis

    NASA Technical Reports Server (NTRS)

    Stansbery, Eugene G.; Johnson, N. L.

    2012-01-01

    The National Aeronautics and Space Administration (NASA) deployed the Upper Atmosphere Research Satellite (UARS) from the Space Shuttle payload bay during the STS-48 mission in September, 1991. The 5700 kg satellite was decommissioned in December, 2005 and was maneuvered into a lower altitude orbit to shorten its on-orbit lifetime to reduce the probability of a debris producing accidental collision. The satellite reentered the Earth s atmosphere over the Pacific Ocean on September 24, 2011. Analysis by NASA s Orbital Debris Program Office using the ORSAT software predicted that approximately two dozen fragments from UARS would survive reentry to reach the ground. This presentation will discuss the reentry predictions made in the days prior to the reentry and compare the UARS reentry with other historical reentries. It will also present the results of the ORSAT analysis showing predicted surviving reentry objects

  6. Re-Entry Women; Some Programmatic Considerations.

    ERIC Educational Resources Information Center

    Bolton, Mary G.

    A six-week course titled "You Too Can Return to College" at the University of California at Davis is designed to assist adult women reentering college. Returning women were found to be lacking in confidence, had low self-expectations, and needed specialized counseling. The reassessment course is offered through the Extension Division of…

  7. A new Green's function Monte Carlo algorithm for the solution of the two-dimensional nonlinear Poisson–Boltzmann equation: Application to the modeling of the communication breakdown problem in space vehicles during re-entry

    SciTech Connect

    Chatterjee, Kausik; Roadcap, John R.; Singh, Surendra

    2014-11-01

    The objective of this paper is the exposition of a recently-developed, novel Green's function Monte Carlo (GFMC) algorithm for the solution of nonlinear partial differential equations and its application to the modeling of the plasma sheath region around a cylindrical conducting object, carrying a potential and moving at low speeds through an otherwise neutral medium. The plasma sheath is modeled in equilibrium through the GFMC solution of the nonlinear Poisson–Boltzmann (NPB) equation. The traditional Monte Carlo based approaches for the solution of nonlinear equations are iterative in nature, involving branching stochastic processes which are used to calculate linear functionals of the solution of nonlinear integral equations. Over the last several years, one of the authors of this paper, K. Chatterjee has been developing a philosophically-different approach, where the linearization of the equation of interest is not required and hence there is no need for iteration and the simulation of branching processes. Instead, an approximate expression for the Green's function is obtained using perturbation theory, which is used to formulate the random walk equations within the problem sub-domains where the random walker makes its walks. However, as a trade-off, the dimensions of these sub-domains have to be restricted by the limitations imposed by perturbation theory. The greatest advantage of this approach is the ease and simplicity of parallelization stemming from the lack of the need for iteration, as a result of which the parallelization procedure is identical to the parallelization procedure for the GFMC solution of a linear problem. The application area of interest is in the modeling of the communication breakdown problem during a space vehicle's re-entry into the atmosphere. However, additional application areas are being explored in the modeling of electromagnetic propagation through the atmosphere/ionosphere in UHF/GPS applications.

  8. Asset and prime - Gliding re-entry test vehicles

    NASA Astrophysics Data System (ADS)

    Powell, J. W.; Hengeveld, E.

    1983-08-01

    The history of the USAF development programs for winged controlled-reentry vehicles based on a dynamic-gliding principle, ASSET (1957-1965) and PRIME (1964-1967), is recounted. The ASSET program, developed from the initial Dyna-Soar project, comprised three aerothermodynamic-structural vehicles and three aerothermoelastic vehicles, all utilizing exotic refractory metal structures partially coated with silicon-boron, zirconia-ceramic nose caps, and LV-2C Thor launchers. The three PRIME SV-5D vehicles employed elastomeric-blanket ablative heat shields and molded carbon-phenolic-composite nose caps and were launched by SLV-3 Atlas rockets. It is noted that these projects, although successful, did not lead directly to the production of lifting-body or winged reentry vehicles, but rather provided data useful in the later Shuttle development program.

  9. STS-107 Debris Characterization Using Re-entry Imaging

    NASA Technical Reports Server (NTRS)

    Raiche, George A.

    2009-01-01

    Analysis of amateur video of the early reentry phases of the Columbia accident is discussed. With poor video quality and little theoretical guidance, the analysis team estimated mass and acceleration ranges for the debris shedding events observed in the video. Camera calibration and optical performance issues are also described.

  10. Thermal Analysis of Small Re-Entry Probe

    NASA Technical Reports Server (NTRS)

    Agrawal, Parul; Prabhu, Dinesh K.; Chen, Y. K.

    2012-01-01

    The Small Probe Reentry Investigation for TPS Engineering (SPRITE) concept was developed at NASA Ames Research Center to facilitate arc-jet testing of a fully instrumented prototype probe at flight scale. Besides demonstrating the feasibility of testing a flight-scale model and the capability of an on-board data acquisition system, another objective for this project was to investigate the capability of simulation tools to predict thermal environments of the probe/test article and its interior. This paper focuses on finite-element thermal analyses of the SPRITE probe during the arcjet tests. Several iterations were performed during the early design phase to provide critical design parameters and guidelines for testing. The thermal effects of ablation and pyrolysis were incorporated into the final higher-fidelity modeling approach by coupling the finite-element analyses with a two-dimensional thermal protection materials response code. Model predictions show good agreement with thermocouple data obtained during the arcjet test.

  11. Second-order analytic solutions for re-entry trajectories

    NASA Astrophysics Data System (ADS)

    Vinh, Nguyen X.; Kim, Eun-Kyou; Greenwood, Donald T.

    With the development of aeroassist technology, either for near-earth operations or for planetary aero-capture, it is of interest to have accurate analytic solutions for the speed, flight path angle and altitude during the atmospheric passage. For a future aerospace plane which uses the accumulated kinetic energy to glide for a long range, explicit relations among the main state variables are also useful for guidance purposes. In this paper we have used normalization to put the equations of motion for planar entry around a non-rotating planet into a form which is suitable for an analytic integration. Explicit and accurate solutions are then obtained for ballistic fly-through trajectories, lifting skip trajectories and equilibrium glide trajectories.

  12. Investigation of the Performance Characteristics of Re-Entry Vehicles

    DTIC Science & Technology

    2005-09-01

    uicontrol ...8217,... ’Visible’,’on’,... ’HorizontalAlignment’, ’center’); edit4 = uicontrol (’Style’,’Edit’,’Units’,’Normalized’,... 53...8217,’on’,... ’HorizontalAlignment’, ’center’); edit5 = uicontrol (’Style’,’Edit’,’Units’,’Normalized’,...

  13. Aerodynamics of the EXPERT Re-Entry Ballistic Vehicle

    NASA Astrophysics Data System (ADS)

    Kharitonov, A. M.; Adamov, N. P.; Mazhul, I. I.; Vasenyov, L. G.; Zvegintsev, V. I.; Muylaert, J. M.

    2009-01-01

    Since 2002 till now, experimental studies of the EXPERT reentry capsule have been performed in ITAM SB RAS wind tunnels. These studies have been performed in consecutive ISTC project No. 2109, 3151, and currently ongoing project No. 3550. The results of earlier studies in ITAM wind tunnels can be found in [1-4]. The present paper describes new data obtained for the EXPERT model.

  14. Coiled tubing used for slim hole re-entry

    SciTech Connect

    Traonmilin, E. ); Newman, K. )

    1992-02-17

    A coiled tubing unit with slim hole tools successfully re-entered and cored an existing Elf Aquitaine vertical well in the Paris basin in France. This experiment proved that coiled tubing could be used to drill, core, and test a slim hole well. Elf Aquitaine studied the use of coiled tubing for drilling inexpensive exploration wells in the Paris basin. As a result of this study, Elf believed that coiled tubing exploration drilling could significantly reduce exploration costs. This paper reports on a number of questions raised by this study: Can coiled tubing be used effectively to drill slim open hole How would the drilling rate compare with that of a conventional drilling rig If the rate were too slow, coiled tubing might not be economical. Can a straight vertical well be drilled Coiled tubing pipe has a residual curvature from bending over the reel and gooseneck. Will this curvature make it impossible to drill straight Can the coiled tubing also be used to take cores Once the hole is drilled, can it be tested with coiled tubing

  15. Secondary Level Re-Entry of Young Canadian Adult Learners

    ERIC Educational Resources Information Center

    MacGregor, Cassandra; Ryan, Thomas G.

    2011-01-01

    This paper illuminates and details some of the traits, pressures and semi-autonomy of the young adult between the ages of 18 and 24 who must confront the barriers and challenges upon returning to secondary school within the high school and the adult education centre context. Focusing on these young adults is fundamentally important to begin to…

  16. Rescue Shuttle Flight Re-Entry: Controlling Astronaut Thermal Exposure

    NASA Technical Reports Server (NTRS)

    Gillis, David B.; Hamilton, Douglas; Ilcus, Stana; Stepaniak, Phil; Polk, J. D.; Son, Chang; Bue, Grant

    2008-01-01

    A rescue mission for the STS-125 Hubble Telescope Repair Mission requires reentry from space with 11 crew members aboard, exceeding past cabin thermal load experience and risking crew thermal stress potentially causing cognitive performance and physiological decrements. The space shuttle crew cabin air revitalization system (ARS) was designed to support a nominal crew complement of 4 to 7 crew and 10 persons in emergencies, all in a shirt-sleeve environment. Subsequent to the addition of full pressure suits with individual cooling units, the ARS cannot maintain a stable temperature in the crew cabin during reentry thermal loads. Bulk cabin thermal models, used for rescue mission planning and analysis of crew cabin air, were unable to accurately represent crew workstation values of air flow, carbon dioxide, and heat content for the middeck. Crew temperature models suggested significantly elevated core temperatures. Planning for an STS-400 potential rescue of seven stranded crew utilized computational fluid dynamics (CFD) models to demonstrate inhomogeneous cabin thermal properties and improve analysis compared to bulk models. In the absence of monitoring of crew temperature, heart rate, metabolic rate and incomplete engineering data on the performance of the integrated cooling garment/cooling unit (ICG/CU) at cabin temperatures above 75 degrees F, related systems & models were reevaluated and tests conducted with humans in the loop. Changes to the cabin ventilation, ICU placement, crew reentry suit-donning procedures, Orbiter Program wave-off policy and post-landing power down and crew extraction were adopted. A second CFD and core temperature model incorporated the proposed changes and confirmed satisfactory cabin temperature, improved air distribution, and estimated core temperatures within safe limits. CONCLUSIONS: These changes in equipment, in-flight and post-landing procedures, and policy were implemented for the STS-400 rescue shuttle & will be implemented in any future rescue flights from the International Space Station of stranded shuttle crews.

  17. Artist's Concept of X-37 Re-entry

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Pictured is an artist's concept of the experimental X-37 Reusable Launch Vehicle re-entering Earth`s atmosphere. NASA and the Boeing Company entered a cooperative agreement to develop and fly a new experimental space plane called the X-37 that would be ferried into orbit to test new technologies. The reusable space plane incorporated technologies aimed at significantly cutting the cost of space flight. The X-37 would be carried into orbit by the Space Shuttle or be launched by an expendable rocket. After the X-37 was deployed, it would remain in orbit up to 21 days, performing a variety of experiments before re-entering the Earth's atmosphere and landing. The X-37 program was discontinued in 2003.

  18. STS-81 crew on middeck preparing for re-entry

    NASA Image and Video Library

    1997-02-14

    STS081-308-032 (12-22 Jan. 1997) --- Astronaut Marsha S. Ivins appears almost lost among the bags of material to be brought back to Earth at the impending conclusion of the Space Shuttle Atlantis and Russia's Mir Space Station docking mission. Several partial pressure garments which were used for launch and will soon be donned for the entry phase are in upper left.

  19. Re-Entry Simulation and Landing Area for YES2

    NASA Technical Reports Server (NTRS)

    Calzada, Silvia

    2005-01-01

    The REST simulator includes many parameters: a) Inertial <-> Fix to Earth reference system; b) Geodetic <-> Geocentric coordinates; c) Rotational velocity of the Atmosphere; d) Effect of the rotation of the Earth; e) Bulge effect of the Earth; f) Spherical harmonic expansion for the Earth s gravitational potential, J2 (zonal); g) Heat flux, temperature in the wall; h) Drag coefficient for different regimes; i) Flow regime status; j) Density model NRLMSISE-00; k) Wind model HWM-93; l) G2S atmospheric model with the latest meteorological conditions and m) Landing area (Monte Carlo Simulations)

  20. Hypoxia induces re-entry of committed cells into pluripotency

    PubMed Central

    Mathieu, Julie; Zhang, Zhan; Nelson, Angelique; Lamba, Deepak A.; Reh, Thomas A.; Ware, Carol; Ruohola-Baker, Hannele

    2014-01-01

    Adult stem cells reside in hypoxic niches and embryonic stem cells (ESCs) are derived from a low oxygen environment. However, it is not clear whether hypoxia is critical for stem cell fate since for example human ESCs (hESCs) are able to self-renew in atmospheric oxygen concentrations as well. We now show that hypoxia can govern cell fate decision since hypoxia alone can revert hESC- or iPSC-derived differentiated cells back to a stem cell-like state, as evidenced by re-activation of an Oct4-promoter reporter. Hypoxia-induced “de-differentiated” cells also mimic hESCs in their morphology, long-term self-renewal capacity, genome wide mRNA and miRNA profiles, Oct4 promoter methylation state, cell surface markers TRA1-60 and SSEA4 expression and capacity to form teratomas. These data demonstrate that hypoxia can influence cell fate decisions and could elucidate hypoxic niche function. PMID:23765801

  1. ARV Re-Entry Module Aerodynmics And Aerothermodynamics

    NASA Astrophysics Data System (ADS)

    Scheer, Heloise; Tran, Philippe; Berthe, Philippe

    2011-05-01

    Astrium-ST is the prime contractor of ARV phase A and is especially in charge of designing the Reentry Module (RM). The RM aeroshape has been defined following a trade-off. High level system requirements were derived with particular attention paid on minimum lift-over-drag ratio, trim incidence, centre-of-gravity lateral off-set and box size, volumetric efficiency, attitude at parachute deployment, flight heritage and aeroheating. Since moderate cross-range and thus L/D ratio were required, the aeroshape trade-off has been performed among blunt capsule candidates. Two front- shield families were considered: spherical (Apollo/ARD/Soyuz type) and sphero-conical (CTV type) segment front-shield. The rear-cone angle was set to 20° for internal pressurized volume and accommodation purposes. Figures of merit were assessed and a spherical front- shield of ARD type with a 20° rear-cone section was selected and proposed for further investigations. Maximum benefits will be taken from ARD flight heritage. CFD and WTT campaigns plans will be presented including preliminary results.

  2. Re-entry vehicle shape for enhanced performance

    NASA Technical Reports Server (NTRS)

    Brown, James L. (Inventor); Garcia, Joseph A. (Inventor); Prabhu, Dinesh K. (Inventor)

    2008-01-01

    A convex shell structure for enhanced aerodynamic performance and/or reduced heat transfer requirements for a space vehicle that re-enters an atmosphere. The structure has a fore-body, an aft-body, a longitudinal axis and a transverse cross sectional shape, projected on a plane containing the longitudinal axis, that includes: first and second linear segments, smoothly joined at a first end of each the first and second linear segments to an end of a third linear segment by respective first and second curvilinear segments; and a fourth linear segment, joined to a second end of each of the first and second segments by curvilinear segments, including first and second ellipses having unequal ellipse parameters. The cross sectional shape is non-symmetric about the longitudinal axis. The fourth linear segment can be replaced by a sum of one or more polynomials, trigonometric functions or other functions satisfying certain constraints.

  3. An uncommon case of spontaneous conversion from AV re-entry tachycardia to AV nodal re-entry tachycardia in a patient with dual tachycardia.

    PubMed

    Zeljković, Ivan; Benko, Ivica; Manola, Šime; Radeljić, Vjekoslav; Pavlović, Nikola

    2015-01-01

    We report the case of a 46-year old patient in whom an electrophysiology study (EP) was performed due to paroxysmal supraventricular tachycardia documented in 12-lead ECG. During the EP study, supraventricular tachycardia was induced easily and it corresponded to orthodromic AV reentry tachycardia (AVRT) using a concealed left free wall accessory pathway. However, during the study AVRT spontaneously and repeatedly converted to the typical slow-fast AV node reentry tachycardia (AVNRT). Both accessory and AV nodal slow pathways were ablated, due to the finding that both AVRT and AVNRT were independently inducible during the EP study.

  4. Ares I-X First Stage Internal Aft Skirt Re-Entry Heating Data and Modeling

    NASA Technical Reports Server (NTRS)

    Schmitz, Craig P.; Tashakkor, Scott B.

    2011-01-01

    The CLVSTATE engineering code is being used to predict Ares-I launch vehicle first stage reentry aerodynamic heating. An engineering analysis is developed which yields reasonable predictions for the timing of the first stage aft skirt thermal curtain failure and the resulting internal gas temperatures. The analysis is based on correlations of the Ares I-X internal aft skirt gas temperatures and has been implemented into CLVSTATE. Validation of the thermal curtain opening models has been accomplished using additional Ares I-X thermocouple, calorimeter and pressure flight data. In addition, a technique which accounts for radiation losses at high altitudes has been developed which improves the gas temperature measurements obtained by the gas temperature probes (GTP). Updates to the CLVSTATE models are shown to improve the accuracy of the internal aft skirt heating predictions which will result in increased confidence in future vehicle designs

  5. NASA's DC-8 Lab Heads to Record Hayabusa Re-entry

    NASA Image and Video Library

    A planeload of scientists plan to catch a glimpse of the fiery return to Earth of the Japanese spacecraft Hayabusa over Australia from NASA's DC-8 flying laboratory on June 13, 2010. Scientists and...

  6. CFD Analysis of Tile-Repair Augers for the Shuttle Orbiter Re-Entry Aeroheating

    NASA Technical Reports Server (NTRS)

    Mazaheri, Ali R.

    2007-01-01

    A three-dimensional aerothermodynamic model of the shuttle orbiter's tile overlay repair (TOR) sub-assembly is presented. This sub-assembly, which is an overlay that covers the damaged tiles, is modeled as a protuberance with a constant thickness. The washers and augers that serve as the overlay fasteners are modeled as cylindrical protuberances with constant thicknesses. Entry aerothermodynamic cases are studied to provide necessary inputs for future thermal analyses and to support the space-shuttle return-to-flight effort. The NASA Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA) is used to calculate heat transfer rate on the surfaces of the tile overlay repair and augers. Gas flow is modeled as non-equilibrium, five species air in thermal equilibrium. Heat transfer rate and surface temperatures are analyzed and studied for a shuttle orbiter trajectory point at Mach 17.85. Computational results show that the average heat transfer rate normalized with respect to its value at body point 1800 is about BF=1.9 for the auger head. It is also shown that the average BF for the auger and washer heads is about BF=2.0.

  7. COmbustion- and Re-Entry-PLasma research Using the ion Storage facility DESIREE (COREPLUS)

    DTIC Science & Technology

    2013-10-01

    curves for the [by definition infinite number of] molecular Rydberg states which play a role in this reaction, but also by the fact that these...possible direct electron transfer (i.e. long range processes without forming intermediate transient states) product channels are endothermic . Taking...the first of these reactions in a little more detail, and looking at the first two exothermic channels: Na+ + PO3- → Na + PO2 + O -0.4 eV 5a1

  8. Multiple Choices, Multiple Chances: Fostering Re-Entry Pathways for First Generation College Students

    ERIC Educational Resources Information Center

    Ryken, Amy E.

    2006-01-01

    Student or program deficiencies are the classic explanation for student departure from community college partners of career technical education programs. However, a complex set of factors impact college attendance, persistence, and departure decision-making. Participants' experiences both within and outside program structures can reshape long-term…

  9. Review of ESOC re-entry prediction results of Salyut-7/Kosmos-1686

    NASA Technical Reports Server (NTRS)

    Klinkrad, H.

    1991-01-01

    An overview of activities at ESA/ESOC during the followup of the Salyut-7/Kosmos-1686 decay, and of related cooperations with space agencies, research institutes, and national bodies within the ESA Member States, within the U.S. and within the USSR, is presented. A postflight analysis indicated areas for improvement in the forecast procedures, especially during the last day of the orbital lifetime. Corresponding revised decay predictions are presented for Salyut-7/Kosmos-1686, and the improved procedures are verified by an analysis of the reentries of Kosmos-1402A and Kosmos-1402C.

  10. A New Guidance Method for a Delta V and Re-entry Constrained Orbit Transfer Problem

    DTIC Science & Technology

    2005-06-01

    velocity, and time for these paths was first determined by Johannes Kepler in the year 1619. Rendezvous is a similar class of problem. Instead of a...orbit defined by these values would satisfy the boundary conditions if two-body ( Kepler ) propagation of the state (r1,v1) for ∆t results in a final 34...It was first characterized by Johannes Lambert in 1761. Lambert discovered a relationship between the geometry of the orbit transfer and the transfer

  11. Spatial Multiphysics Models of the Radiation Gas Dynamics of Super Orbital Re-Entry Space Vehicles

    NASA Astrophysics Data System (ADS)

    Surzhikov, S. T.

    2017-05-01

    The multiphysics models of non equilibrium physical and chemical processes that should be considered together with radiative gas dynamic models for a description of the aero physics of super-orbital space vehicles are described. As an example of application of the multiphysics approach a three-dimensional numerical simulation analysis of radiative gas dynamics of Apollo-17 command module is analyzed. The results of calculations are compared with other numerical predictions, analytical correlations, and available experimental data.

  12. Predicting Boundary-Layer Transition on Space-Shuttle Re-Entry

    NASA Technical Reports Server (NTRS)

    Berry, Scott; Horvath, Tom; Merski, Ron; Liechty, Derek; Greene, Frank; Bibb, Karen; Buck, Greg; Hamilton, Harris; Weilmuenster, Jim; Campbell, Chuck; hide

    2008-01-01

    The BLT Prediction Tool ("BLT" signifies "Boundary Layer Transition") is provided as part of the Damage Assessment Team analysis package, which is utilized for analyzing local aerothermodynamics environments of damaged or repaired space-shuttle thermal protection tiles. Such analyses are helpful in deciding whether to repair launch-induced damage before re-entering the terrestrial atmosphere.

  13. Limit Motions of a Slightly Asymmetric Re-Entry Vehicle Acted on by Cubic Damping Moments.

    DTIC Science & Technology

    either circular or planar limit motion. The addition of configurational asymmetry introduces the possibility of more complicated limit motion. The...existence of one-, two- and three-mode stable limit motions is studied by quasi-linear analysis and the results verified by numerical integration of the exact differential equation.

  14. Social Barriers to Successful Re-entry into Mainstream Organizational Culture: Perceptions of People with Disabilities.

    ERIC Educational Resources Information Center

    Boyle, Mike A.

    1997-01-01

    Case studies of seven workers with physical impairments identified four categories of barriers: negative social image, a rehabilitation system that controlled career options, job completion methods that denied access to occupations, and image campaigns making organizations appear to be responsive to disabilities. The Americans with Disabilities…

  15. Nonlinear gain of a millimetre wave antenna array mounted on a re-entry vehicle

    NASA Astrophysics Data System (ADS)

    Sharma, Ashok Kumar; Kumar, Ashok

    2007-04-01

    A millimetre wave antenna array, mounted on a space vehicle re-entering the Earth's atmosphere, encounters a high density plasma around it. At high antenna power, the millimetre wave field heats the electrons nonuniformly. The electron temperature, Te, follows the antenna pattern, being maximum along the direction of the principal maximum (z-axis) and falling off rapidly across it. The ambipolar plasma diffusion under the pressure gradient force creates a refractive index profile with maximum on the z-axis, leading to self-convergence of the millimetre wave and enhancement in the effective gain of the antenna.

  16. What drives hydrophobic polymer collapse and re-entry transitions in miscible good solvents?

    NASA Astrophysics Data System (ADS)

    Rodriguez Ropero, Francisco; Hajari, Timir; van der Vegt, Nico F. A.

    Herein, we study co-nonsolvency of poly(N-isopropylacrylamide) (PNiPAM) in methanol aqueous solutions. Our results show that both the coil-to-globule transition at low methanol concentrations and the globule-to-coil re-entrance at high methanol concentrations are entropy driven. At low alcohol content, methanol preferentially binds to the PNiPAM globule and drives polymer collapse. Rather than being driven by electrostatic, hydrogen bonding or bridging-type interactions with the globule, preferential methanol binding is found to result from a significant increase of the chain configurational entropy, stabilizing methanol-enriched globular structures over wet globular structures in neat water. The globule-to-coil re-entrance at high methanol concentrations is instead driven by changes in solvent-excluded volume of the coil and globular states imparted by a decrease in solvent density with increasing methanol content of the solution. The co-nonsolvency mechanism proposed in this contribution provides a new angle on how to develop Coarse Grained simulation models for responsive soft matter systems. Moreover, several of the solvation effects described in this contribution can be incorporated in theories for cosolvent-induced conformational transitions in dilute polymer solutions. This research was supported by the German Research Foundation (DFG) within the Collaborative Research Center ``Multiscale Simulation Methods for Soft Matter Systems'' (SFB-TRR146).

  17. Numerical Study of Flow Augmented Thermal Management for Entry and Re-Entry Environments

    NASA Technical Reports Server (NTRS)

    Cheng, Gary C.; Neroorkar, Kshitij D.; Chen, Yen-Sen; Wang, Ten-See; Daso, Endwell O.

    2007-01-01

    The use of a flow augmented thermal management system for entry and re-entr environments is one method for reducing heat and drag loads. This concept relies on jet penetration from supersonic and hypersonic counterflowing jets that could significantly weaken and disperse the shock-wave system of the spacecraft flow field. The objective of this research effort is to conduct parametric studies of the supersonic flow over a 2.6% scale model of the Apollo capsule, with and without the counterflowing jet, using time-accurate and steady-state computational fluid dynamics simulations. The numerical studies, including different freestream Mach number angle of attack counterflowing jet mass flow rate, and nozzle configurations, were performed to examine their effect on the drag and beat loads and to explore the counternowing jet condition. The numerical results were compared with the test data obtained from transonic blow-down wind-tunnel experiments conducted independently at NASA MSFC.

  18. STS-104 CDR Lindsey on forward flight deck prior to re-entry

    NASA Image and Video Library

    2001-07-25

    STS104-345-021 (25 July 2001) --- Attired in his shuttle launch and entry suit, astronaut Steven W. Lindsey, STS-104 commander, looks over a procedures checklist at the commander’s station on the forward flight deck of the space shuttle Atlantis.

  19. The Effect of Child Support on Welfare Exits and Re-Entries

    ERIC Educational Resources Information Center

    Huang, Chien-Chung; Kunz, James; Garfinkel, Irwin

    2002-01-01

    Much of the literature on welfare dynamics has focused on the effects of recipient characteristics and state-level characteristics such as welfare benefits and economic conditions; there has been very little analysis on the effects of child support. This paper, using the 1979-1996 National Longitudinal Survey of Youth, examines whether child…

  20. The Re-Entry Safety of H-II Transfer Vehicle(HTV)

    NASA Astrophysics Data System (ADS)

    Ozawa, Masayuki; Sasaki, Hiroshi; Yoshihara, Toru

    2010-09-01

    JAXA has recently established own regulation for the controlled reentry in addition to the existing requirements applicable to the natural reentry. This regulation added the requirements which addresses the safety control philosophy, the definition of the control system, the trajectory deviation to be considered, the criterion of the expected number of casualties(Ec) and other related requirements / processes. This paper introduces the contents of this regulation and the first application result to the HTV-1 reentry. The safety evaluation result for the HTV-1 reentry is also summarized.

  1. Adult Re-Entry Students: Experiences Preceding Entry into a Rural Appalachian Community College

    ERIC Educational Resources Information Center

    Genco, Jessica T.

    2007-01-01

    Mountain Empire Community College (MECC)'s service region covers the extreme southwestern corner of Virginia and includes four counties and one city: Dickenson, Lee, Scott, and Wise Counties, and the city of Norton. With a service region population of 93,000 residents, MECC currently serves over 5,000 students annually (Mountain Empire Community…

  2. Entry, Descent, and Landing Operations Analysis for the Genesis Re-Entry Capsule

    NASA Technical Reports Server (NTRS)

    Desai, Prasun N.; Lyons, Dan T.

    2005-01-01

    On September 8, 2004, the Genesis spacecraft returned to Earth after spending 29 months about the sun-Earth libration point collecting solar wind particles. Four hours prior to Earth arrival, the entry capsule containing the samples was released for entry and subsequent landing at the Utah Test and Training Range. This paper provides an overview of the entry, descent, and landing trajectory analysis that was performed during the Mission Operations Phase leading up to final approach to Earth. The operations effort accurately delivered the entry capsule to the desired landing site. The final landing location was 8.3 km from the target, and was well within the allowable landing area. Preliminary reconstruction analyses indicate that the actual entry trajectory was very close to the pre-entry prediction.

  3. Entry, Descent, and Landing Operations Analysis for the Stardust Re-Entry Capsule

    NASA Technical Reports Server (NTRS)

    Desao, Prasun N.; Lyons, Dan T.; Tooley, Jeff; Kangas, Julie

    2006-01-01

    On the morning of January 15, 2006, the Stardust capsule successfully landed at the Utah Test and Training range in northwest Utah returning cometary samples from the comet Wild-2. An overview of the entry, descent, and landing (EDL) trajectory analysis that was performed for targeting during the Stardust Mission Navigation Operations Phase upon final approach to Earth is described. In addition, how the predicted landing location and the resulting overall 99 percentile landing footprint ellipse obtained from a Monte Carlo analysis changed over the final days and hours prior to entry is also presented. The navigation and EDL operations effort accurately delivered the entry capsule to the desired landing site. The final landing location was 8.1 km from the target, which was well within the allowable landing area.

  4. Effecting Successful Community Re-Entry: Systems of Care Community Based Mental Health Services

    ERIC Educational Resources Information Center

    Estes, Rebecca I.; Fette, Claudette; Scaffa, Marjorie E.

    2005-01-01

    The need for system reform for child and adolescent mental health services, long recognized as a vital issue, continues to challenge mental health professionals. While past legislation has not adequately addressed the issues, the 2003 President's New Freedom Commission may begin to reorient mental health systems toward recovery. Supported by this…

  5. Rudder/Fin Seal Investigations for the X-38 Re-Entry Vehicle

    NASA Technical Reports Server (NTRS)

    Dunlap, Patrick H., Jr.; Steinetz, Bruce M.; Curry, Donald M.

    2000-01-01

    NASA is currently developing the X-38 vehicle that will be used to demonstrate the technologies required for a crew return vehicle (CRV) for the International Space Station. The X-38 control surfaces require high temperature seals to limit hot gas ingestion and transfer of heat to underlying low-temperature structures to prevent over-temperature of these structures and possible loss of the vehicle. This paper presents results for thermal analyses and flow and compression tests conducted on as-received and thermally exposed seals for the rudder/fin location of the X-38. A thermal analysis of the rudder/fin dual seal assembly based on representative heating rates on the windward surface of the rudder/fin area predicted a peak seal temperature of 1900 F. The temperature-exposed seals were heated in a compressed state at 1900 F corresponding to the predicted peak temperature. Room temperature compression tests were performed to determine load versus linear compression, preload, contact area, stiffness, and resiliency characteristics for the as-received and temperature-exposed seals. Temperature exposure resulted in permanent set and loss of resiliency in these seals. Unit loads and contact pressures for the seals were below the 5 lb/in. and 10 psi limits set to limit the loads on the Shuttle thermal tiles that the seals seal against in the rudder/fin location. Measured seal flow rates for a double seal were about 4.5 times higher than the preliminary seal flow goal. The seal designs examined in this study are expected to be able to endure the high temperatures that they will be exposed to for a single-use life. Tests performed herein combined with future analyses, arc jet tests, and scrubbing tests will be used to select the final seal design for this application.

  6. School Re-Entry of the Brain Injured Student: A Case Study of Peer Inservicing.

    ERIC Educational Resources Information Center

    Abbot, Nan; Wilkinson, Laurie

    1992-01-01

    This case study describes the development of a model peer support program during the school reintegration of an adolescent girl who sustained a traumatic brain injury. A series of meetings was held with the girl's social network to provide information, guidance, acknowledgement of friends' feelings, interventions for behavior problems, and…

  7. Social Hostility and the "Dropout" Syndrome: Leadership Assisting Youths' Re-Entry into School?

    ERIC Educational Resources Information Center

    Brown, Byron A.

    2010-01-01

    The study investigated experiences of dropouts in schools in rural secondary schools in the Eastern Cape, South Africa. Ten learners who previously dropped out of school described their experiences in school subsequent to re-enrolling. The implications of these experiences for educational leadership were explored. Using a qualitative approach,…

  8. Model surface conductivity effect for the electromagnetic heat shield in re-entry flight

    SciTech Connect

    Matsuda, Atsushi; Kawamura, Masaaki; Konigorski, Detlev; Takizawa, Yuji; Abe, Takashi

    2008-12-15

    Effects of model surface conductivity on shock layer enhancement by an applied magnetic field in weakly ionized supersonic plasma flow with a large Hall parameter ({beta}{approx}300) was investigated experimentally. The shock layer structures of test models of two kinds were measured using laser absorption spectroscopy, in the large Hall parameter situation. One was an insulated model; the other was a conductive spherical blunt model. The shock layer enhancement phenomenon by the applied magnetic field was more pronounced for the insulated model than for the conductive model. This tendency agrees with the computational fluid dynamics result, at least qualitatively.

  9. Re-Entry Trauma: Asian Re-Integration after Study in the West

    ERIC Educational Resources Information Center

    Pritchard, Rosalind

    2011-01-01

    Many students who re-locate from host to home country are said to undergo a process of reverse culture shock akin to bereavement, involving stages of a grieving process. This has been likened to a "W-curve" in which feelings fluctuate before reaching a more balanced state. The present study examined the re-acculturation of Taiwanese and…

  10. Re-entry: online virtual worlds as a healing space for veterans

    NASA Astrophysics Data System (ADS)

    Morie, Jacquelyn Ford

    2009-02-01

    We describe a project designed to use the power of online virtual worlds as a place of camaraderie and healing for returning United States military veterans-a virtual space that can help them deal with problems related to their time of service and also assist in their reintegration into society. This veterans' space is being built in Second Life®, a popular immersive world, under consultation with medical experts and psychologists, with several types of both social and healing activities planned. In addition, we address several barrier issues with virtual worlds, including lack of guides or helpers to ensure the participants have a quality experience. To solve some of these issues, we are porting the advanced intelligence of the ICT's virtual human characters to avatars in Second Life®, so they will be able to greet the veterans, converse with them, guide them to relevant activities, and serve as informational agents for healing options. In this way such "avatar agents" will serve as autonomous intelligent characters that bring maximum engagement and functionality to the veterans' space. This part of the effort expands online worlds beyond their existing capabilities, as currently a human being must operate each avatar in the virtual world; few autonomous characters exist. As this project progresses we will engage in an iterative design process with veteran participants who will be able to advise us, along with the medical community, on what efforts are well suited to, and most effective within, the virtual world.

  11. Social Hostility and the "Dropout" Syndrome: Leadership Assisting Youths' Re-Entry into School?

    ERIC Educational Resources Information Center

    Brown, Byron A.

    2010-01-01

    The study investigated experiences of dropouts in schools in rural secondary schools in the Eastern Cape, South Africa. Ten learners who previously dropped out of school described their experiences in school subsequent to re-enrolling. The implications of these experiences for educational leadership were explored. Using a qualitative approach,…

  12. SHARK-MAXUS 8 Experiment: A Technology Demonstrator for Re-Entry Drop Capsule

    NASA Astrophysics Data System (ADS)

    Gardi, R.; del Vecchio, A.; Russo, G.; Weikert, S.; Cremaschi, F.; Ortega, G.; Rinalducci, A.; Martinez Barrio, A.

    2012-01-01

    SHARK (Sounding Hypersonic Atmospheric Re- entering 'Kapsule') is a small capsule designed and realized at CIRA under ESA contract. The aim of the project is to prove the feasibility to set up a low cost experimental space platform and execute a reentry test flight by dropping a capsule from a sounding rocket. The main payload of SHARK is a UHTC (Ultra High Temperature Ceramic) component, machined from scraps of previous ground tests executed in the CIRA Plasma Wind Tunnel SCIROCCO. SHARK was successfully launched on March the 26th 2010, by the European sounding rocket MAXUS 8. The separation occurred nominally during the ascent parabola and successfully executed its 15 minutes ballistic flight (achieving more than 700 km altitude) and then re-entered the atmosphere and landed. The capsule was recovered on the 1st of July 2010 and the data retrieved from the memory unit. This paper will present a mission overview, with particular details on the safety and operational aspects.

  13. Inverse Temperature Mapping of Re-Entry Vehicle Control Surfaces Using Infrared Thermography

    NASA Astrophysics Data System (ADS)

    Pereira, C.; Hirtz, B.; Vuilleumier, A.; Roesgen, T.; Vos, J.

    2009-01-01

    This paper summarizes the development of an optical system to deliver rear face temperatures thermal maps of an EXPERT vehicle flap using near infrared thermography. The optical system consists of a wide angle lens assembly placed behind the flap, a fiber optic cable and a high rate near infrared camera. The camera transfers images to an autonomous data handling unit located on a colder area of the vehicle. After flight the temperature on the flap windward face is computed using the stored thermal maps as input to a coupled fluid dynamics-heat transfer calculation. The system has been successfully qualified for the EXPERT mission and the inverse temperature reconstruction will be tested in the Scirocco Plasma Wind tunnel. A further evolution of this system allowing simultaneous measurement of temperature and emissivity is planned for the IXV vehicle

  14. Rudder/Fin Seal Investigations for the X-38 Re-Entry Vehicle

    NASA Technical Reports Server (NTRS)

    Dunlap, Patrick H., Jr.; Steinetz, Bruce M.; Curry, Donald M.

    2001-01-01

    NASA is currently developing the X-38 vehicle that will be used to demonstrate the technologies required for a crew return vehicle (CRV) for the International Space Station (ISS). The CRV will serve both as an ambulance for medical emergencies and as an evacuation vehicle for the Space Station. Control surfaces on the X-38 (body flaps and rudders/fins) require high temperature seals to limit hot gas ingestion and transfer of heat to underlying low-temperature structures to prevent over-temperature of these structures and possible loss of the vehicle. NASA's Johnson Space Center (JSC) and Glenn Research Center (GRC) are working together to develop and evaluate seals for the rudder/fin control surfaces. The specific objectives of this study are to measure seal flow rates, resiliency, and unit loads in as-received and temperature-exposed conditions and compare the measured results to property goals where applicable. Areas for future work would then be identified.

  15. Rudder/Fin Seal Investigations for the X-38 Re-Entry Vehicle

    NASA Technical Reports Server (NTRS)

    Dunlap, Patrick H., Jr.; Steinetz, Bruce M.; Curry, Donald M.

    2000-01-01

    NASA is currently developing the X-38 vehicle that will be used to demonstrate the technologies required for a crew return vehicle (CRV) for the International Space Station. The X-38 control surfaces require high temperature seals to limit hot gas ingestion and transfer of heat to underlying low-temperature structures to prevent over-temperature of these structures and possible loss of the vehicle. This paper presents results for thermal analyses and flow and compression tests conducted on as-received and thermally exposed seals for the rudder/fin location of the X-38. A thermal analysis of the rudder/fin dual seal assembly based on representative heating rates on the windward surface of the rudder/fin area predicted a peak seal temperature of 1900 F. The temperature-exposed seals were heated in a compressed state at 1900 F corresponding to the predicted peak temperature. Room temperature compression tests were performed to determine load versus linear compression, preload, contact area, stiffness, and resiliency characteristics for the as-received and temperature-exposed seals. Temperature exposure resulted in permanent set and loss of resiliency in these seals. Unit loads and contact pressures for the seals were below the five pounds/inch and ten psi limits set to limit the loads on the Shuttle thermal tiles that the seals seal against in the rudder/fin location. Measured seal flow rates for a double seal were about 4.5 times higher than the preliminary seal flow goal. The seal designs examined in this study are expected to be able to endure the high temperatures that they will be exposed to for a single-use life. Tests performed herein combined with future analyses, arc jet tests, and scrubbing tests will be used to select the final seal design for this application.

  16. Evaluation of non-intrusive flow measurement techniques for a re-entry flight experiment

    NASA Technical Reports Server (NTRS)

    Miles, R. B.; Santavicca, D. A.; Zimmermann, M.

    1983-01-01

    This study evaluates various non-intrusive techniques for the measurement of the flow field on the windward side of the Space Shuttle orbiter or a similar reentry vehicle. Included are linear (Rayleigh, Raman, Mie, Laser Doppler Velocimetry, Resonant Doppler Velocimetry) and nonlinear (Coherent Anti-Stokes Raman, Laser-Induced Fluorescence) light scattering, electron-beam fluorescence, thermal emission, and mass spectroscopy. Flow-field properties were taken from a nonequilibrium flow model by Shinn, Moss, and Simmonds at the NASA Langley Research Center. Conclusions are, when possible, based on quantitative scaling of known laboratory results to the conditions projected. Detailed discussion with researchers in the field contributed further to these conclusions and provided valuable insights regarding the experimental feasibility of each of the techniques.

  17. A New York City Jail-Community Re-Entry Collaboration.

    ERIC Educational Resources Information Center

    Lisante, Timothy F.; Navon, Beth

    2000-01-01

    The progressive Austin H. MacCormick school is located on Rikers Island, New York City's corrections complex. This school issues the most General Educational Development diplomas, with the highest passing rate, of any program within the 14-jail system that has custody of over 140,000 inmates annually. (Author)

  18. Improving Career Re-entry Outcomes for People with Multiple Sclerosis: A Comparison of Two Approaches.

    ERIC Educational Resources Information Center

    Rumrill, Phillip D.; Roessler, Richard T.; Cook, Bryan G.

    1998-01-01

    Reentry workers with multiple sclerosis (n=23) participated with employers and rehabilitation counselors in training seminars; 14 received traditional job search intervention. After 16 weeks, 11 of the 37 had reentered the labor force. Most already had high self-efficacy and career maturity. (SK)

  19. Astronaut Thermal Exposure: Re-Entry After Low Earth Orbit Rescue Mission

    NASA Technical Reports Server (NTRS)

    Gillis, David B.; Hamilton, Douglas; Ilcus, Stana; Stepaniak, Phil; Son, Chang; Bue, Grant

    2009-01-01

    The STS-125 mission, launched May 11, 2009, is the final servicing mission to the Hubble Space Telescope. The repair mission's EVA tasks are described, including: installing a new wide field camera; installing the Cosmic Origins Spectrograph; repairing the Space Telescope Imaging Spectrograph; installing a new outer blanket layer; adding a Soft Capture and Rendezvous System for eventual controlled deorbit in about 2014; replacing the 'A' side Science Instrument Command and Data Handling module; repairing the Advanced Camera for surveys; and, replacing the rate sensor unit gyroscopes, fine guidance sensors and 3 batteries. Additionally, the Shuttle crew cabin thermal environment is described. A CFD model of per person CO2 demonstrates a discrepancy between crew breathing volume and general mid-deck levels of CO2. A follow-on CFD analysis of the mid-deck temperature distribution is provided. Procedural and engineering mitigation plans are presented to counteract thermal exposure upon reentry to the Earth atmosphere. Some of the procedures include: full cold soak the night prior to deorbit; modifying deck stowage to reduce interference with air flow; and early securing of avionics post-landing to reduce cabin thermal load prior to hatch opening. Engineering mitigation activities include modifying the location of the aft starboard ICUs, eliminating the X3 stack and eliminating ICU exhaust air directed onto astronauts; improved engineering data of ICU performance; and, verifying the adequacy of mid-deck temperature control using CFD models in addition to lumped parameter models. Post-mitigation CFD models of mid-deck temperature profiles and distribution are provided.

  20. NASA Upper Atmosphere Research Satellite (UARS) Re-Entry Prediction and Analysis

    NASA Technical Reports Server (NTRS)

    Stansbery, Eugene; Johnson, Nick L.

    2012-01-01

    No NASA or USG human casualty reentry risk limits existed when UARS was designed, built, and launched. Time of reentry estimates were within normal limits NASA, the USG, and some foreign space agencies now seek to limit human casualty risks from reentering space objects to less than 1 in 10,000. UARS was a moderate-sized space object. Uncontrolled reentries of objects more massive than UARS are not frequent, but neither are they unusual. Since the beginning of the space age, there has been no confirmed report of an injury resulting from reentering space objects.

  1. Assessment of the Need for a Re-Entry/Career Change Program for Pharmacists.

    ERIC Educational Resources Information Center

    Bilger, Rhonda L.; Chereson, Rasma S.

    1994-01-01

    A survey of 603 licensed Missouri pharmacists investigated the need for an update/refresher course for pharmacists changing fields within the profession or returning to full-time practice. Pharmacology/new drugs was the most frequently mentioned topic for such a course, and correspondence study was the preferred format. (Author/MSE)

  2. CARINA - A space vehicle with re-entry capabilities for microgravity experiments

    NASA Astrophysics Data System (ADS)

    Borriello, G.; Sansone, A.; Ricciardi, A.

    1992-08-01

    An Italian autonomous space vehicle with recovery capabilities, named CARINA (Capsula di Rientro Non Abitata), is described with special attention given to the technological developments in areas pertaining to the reentry system, including reentry aerothermodynamics and the design of the thermal protection system. Consideration is also given to the configuration of the CARINA vehicle (comprised of the expendable Service Module and the Apollo-like Reentry Module), the subsystems and their performances, the mission life cycle, the microgravity utilization aspects, and the programmatic aspects.

  3. Effecting Successful Community Re-Entry: Systems of Care Community Based Mental Health Services

    ERIC Educational Resources Information Center

    Estes, Rebecca I.; Fette, Claudette; Scaffa, Marjorie E.

    2005-01-01

    The need for system reform for child and adolescent mental health services, long recognized as a vital issue, continues to challenge mental health professionals. While past legislation has not adequately addressed the issues, the 2003 President's New Freedom Commission may begin to reorient mental health systems toward recovery. Supported by this…

  4. Data re-entry overload: time for a paradigm shift in maternity IT?

    PubMed Central

    Fawdry, Rupert; Bewley, Susan; Cumming, Grant; Perry, Helga

    2011-01-01

    This paper provides an overview of maternity information technology (IT) in Britain, questioning the usability, effectiveness and cost efficiency of the current models of implementation of electronic maternity records. UK experience of hand-held paper obstetric notes and computerized records reveals fundamental problems in the relationship between the two complementary methods of recording maternity data. The assumption that paper records would inevitably be replaced by electronic substitutes has proven false; the rigidity of analysable electronic records has led to immense incompatibility problems. The flexibility of paper records has distinct advantages that have so far not been sufficiently acknowledged. It is suggested that continuing work is needed to encourage the standardization of electronic maternity records, via a new co-creative, co-development approach and continuing international electronic community debate. PMID:21969478

  5. A Nonequilibrium Finite-Rate Carbon Ablation Model for Radiating Earth Re-entry Flows

    DTIC Science & Technology

    2015-09-17

    l (m m ) Flow direction Shock front Boundary layer edge Model edge 355 360 365 370 375...tr a l R a d ia n c e ( W ⋅ c m 2 ⋅ µ m 1 ⋅ s r 1 ) 2410 K 2170 K 1920 K 1770 K CN (B - X) Δν = 0 Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe...4):659672, 1964. 8. Baker, R. L . Graphite Sublimation Chemistry Nonequilibrium Eects. AIAA Journal, 15(10):13911397, 1977. 9. Balat-Pichelin,

  6. Parallel, Gradient-Based Anisotropic Mesh Adaptation for Re-entry Vehicle Configurations

    NASA Technical Reports Server (NTRS)

    Bibb, Karen L.; Gnoffo, Peter A.; Park, Michael A.; Jones, William T.

    2006-01-01

    Two gradient-based adaptation methodologies have been implemented into the Fun3d refine GridEx infrastructure. A spring-analogy adaptation which provides for nodal movement to cluster mesh nodes in the vicinity of strong shocks has been extended for general use within Fun3d, and is demonstrated for a 70 sphere cone at Mach 2. A more general feature-based adaptation metric has been developed for use with the adaptation mechanics available in Fun3d, and is applicable to any unstructured, tetrahedral, flow solver. The basic functionality of general adaptation is explored through a case of flow over the forebody of a 70 sphere cone at Mach 6. A practical application of Mach 10 flow over an Apollo capsule, computed with the Felisa flow solver, is given to compare the adaptive mesh refinement with uniform mesh refinement. The examples of the paper demonstrate that the gradient-based adaptation capability as implemented can give an improvement in solution quality.

  7. Facilitating Successful Re-Entries in the United States: Training and Development for Women Returners

    ERIC Educational Resources Information Center

    Greer, Tomika W.

    2013-01-01

    Women returners are women who leave the paid workforce for a period of time following the birth of their child(ren) and subsequently seek to return to paid employment. As women returners attempt to re-enter the workforce, many of them are in need of updating their skills or re-training in a new set of skills. In this study, the training and…

  8. Coming Home: An Exploration of Re-Entry Tension in Outdoor Experiential Education.

    ERIC Educational Resources Information Center

    Meens, Jen; Henderson, Bob

    2000-01-01

    Interviews with seven individuals who took part in travel and wilderness experiences confirm that travelers experience reentry tensions similar to those discussed in research on culture shock among Peace Corp workers, overseas employees, and the military. Stages of reentry and the need for outdoor educators to work with the challenges of reentry…

  9. Maneuver Analysis and Targeting Strategy for the Stardust Re-Entry Capsule

    NASA Technical Reports Server (NTRS)

    Helfrich, Clifford E.; Bhat, Ram; Kangas, Julie; Wilson, Roby; Wong, Mau; Potts, Chris; Williams, Ken

    2006-01-01

    Stardust employed biased maneuvers to limit turns and minimize execution errors. Biased maneuvers also addressed planetary protection and safety issues. Stardust utilized a fixed-direction burn for the final maneuver to match the prevailing attitude so no turns were needed. Performance of the final burn was calibrated in flight.

  10. Hypersonic Flight and the Re-Entry Problem: The Twenty-First Wright Brothers Lecture

    NASA Technical Reports Server (NTRS)

    Allen, H. Julian

    1958-01-01

    Up to this point the discussion of the problems of rocket vehicles has been confined to the effects of phenomena which have in the past been important ones for lower speed aircraft and will continue to be important for aircraft of all speeds. Now with considerable extension of both speed and altitude, other phenomena also become important. The nature of some problems will be altered, as a result, and new problems, of course, will be encountered. First, it is well to note that our interest in bluff bodies for ballistic vehicles in particular, and in rounded-nosed bodies generally, has changed our emphasis in aerodynamics. The detached bow waves which occur with such bodies at high supersonic speeds complicate the calculations of the flow-field characteristics. In the present period, much attention is being given to such studies. In addition, at the very high altitudes attained by most of the rocket-craft, the mean free path of air molecules can be of the same order, or long, compared to the dimensions of the vehicles. Thus, slip-flow and free-molecule-flow studies are of interest, particularly for satellite vehicles." The aerodynatnicist must deal with air having unfamiliar states and properties. Second, at hypersonic speeds where, for example, air is greatly decelerated, it may undergo considerable change in composition, the degree of change depending upon many factors. Dissociation of oxygen and nitrogen molecules can occur and, in addition, thermal ionization of many of the constituents. It is naturally to be expected that the convective heat transfer will, as a result, be altered from what it was for the "perfect" gas, and this has been the subject of much recent research effort. Moreover, the decelerated gas becomes capable of radiating energy and the radiative heat transfer must generally be considered for hypersonic vehicles, particularly for long-range ballistic rockets. It is not only the aerodynamic heating problems that are affected. The fact that at very high air temperature the gas becomes electrically conductive introduces new problems in radio wave transmission and reception. In addition, a conducting gas flow can, of course, be influenced by a magnetic field. The study of such flows, which has been termed "magneto gas dynamics," is still in too primitive a state to indicate how important a role it can play, but many interesting possibilities suggest themselves. Third, our experience with airplanes powered by air-breathing engines has naturally been restricted to the stratosphere, or lower. Our ignorance increases with altitude. For rockets, literally, "the sky's the limit," and it is not surprising that a great emphasis has now been placed on obtaining a more thorough understanding of the whole atmosphere. These studies are not aimed at an understanding of the chemical and physical characteristics alone, but also of the occurrence of high-energy particles, from meteors to cosmic rays, and the nature of the problems they will promote.

  11. Preparing Communities for Re-Entry of Offenders with Mental Illness: The ACTION Approach

    ERIC Educational Resources Information Center

    Vogel, Wendy M.; Noether, Chan D.; Steadman, Henry J.

    2007-01-01

    Approximately 900,000 people with active symptoms of serious mental illness are booked annually into U.S. jails. Of these, about three quarters have a co-occurring substance use disorder. When these people return to the community they have multiple, complex and interrelated treatment needs, which are often exacerbated by release into the…

  12. Re-Entry Trauma: Asian Re-Integration after Study in the West

    ERIC Educational Resources Information Center

    Pritchard, Rosalind

    2011-01-01

    Many students who re-locate from host to home country are said to undergo a process of reverse culture shock akin to bereavement, involving stages of a grieving process. This has been likened to a "W-curve" in which feelings fluctuate before reaching a more balanced state. The present study examined the re-acculturation of Taiwanese and…

  13. Analysis of the Aerodynamic Orbital Transfer Capabilities of a Winged Re-Entry Vehicle

    DTIC Science & Technology

    2002-09-01

    of the spacecraft ( Freidberger , pg. 797). 0 ri r r r V r r t ϖ ν   ∂  = + × = + ∂    & && (8) 0 r r V V V a V V V t iV ν ν ν ν ϖ ν...Academic Publishers, 2001. 14. Freidberger , W.F., ed. International Dictionary of Applied Mathematics, Princeton, NJ: Van Nostrand Co. Inc., 1960

  14. Social Support Reciprocity and Occupational Self-Efficacy Beliefs during Mothers' Organizational Re-Entry

    ERIC Educational Resources Information Center

    Jaeckel, Dalit; Seiger, Christine P.; Orth, Ulrich; Wiese, Bettina S.

    2012-01-01

    The present study assesses the effects of a lack of social support reciprocity at work on employees' occupational self-efficacy beliefs. We assume that the self-efficacy effects of received support and support reciprocity depend on the specific work context (e.g., phase in the process of organizational socialization). 297 women who returned to…

  15. Simulators for the X-38/CRV Parafoil and Re-Entry Phases

    NASA Technical Reports Server (NTRS)

    Delgado, Frank J.; Arcioni, Marco

    2000-01-01

    The X38/CRV is unique in several aspects: it does not afford the pilot a forward view through a window and it utilizes a parafoil in the final landing flight phase. As a result of some of these unique attributes the prototype on-board displays will need to provide enhanced situation awareness to aid a crew member in supervising the onboard GNC software to select a landing site, and possible obstacle avoidance during the final flight phase. In the ESA/ESTEC visualization prototype system the scene is visualized using MultiGen OpenFlight models on high-end SGI machines. The Parafoil Guidance Navigation and Control (PGNC) algorithms are being developed as a joint NASA/ESA venture. These algorithms will be used onboard the vehicle to create nominal flight trajectories for the vehicle to follow. These same algorithms are also used as parafoil simulators in our augmented situation awareness system we are developing. The output of the parafoil simulator is displayed on a Windows-based computer running the LandForm FlightVision software. The FlightVision software is used to create the synthetic environment displays and all the necessary HUD symbology. Maps, such as aeronautical charts, as well as satellite imagery are optionally overlaid on the 3D-terrain model to provide additional situation awareness for the crew.

  16. Current Status on Radiation Modeling for the Hayabusa Re-entry

    NASA Technical Reports Server (NTRS)

    Winter, Michael W.; McDaniel, Ryan D.; Chen, Yih-Kang; Liu, Yen; Saunders, David

    2011-01-01

    On June 13, 2010 the Japanese Hayabusa capsule performed its reentry into the Earths atmosphere over Australia after a seven year journey to the asteroid Itokawa. The reentry was studied by numerous imaging and spectroscopic instruments onboard NASA's DC-8 Airborne Laboratory and from three sites on the ground, in order to measure surface and plasma radiation generated by the Hayabusa Sample Return Capsule (SRC). Post flight, the flow solutions were recomputed to include the whole flow field around the capsule at 11 points along the reentry trajectory using updated trajectory information. Again, material response was taken into account to obtain most reliable surface temperature information. These data will be used to compute thermal radiation of the glowing heat shield and plasma radiation by the shock/post-shock layer system to support analysis of the experimental observation data. For this purpose, lines of sight data are being extracted from the flow field volume grids and plasma radiation will be computed using NEQAIR [4] which is a line-by-line spectroscopic code with one-dimensional transport of radiation intensity. The procedures being used were already successfully applied to the analysis of the observation of the Stardust reentry [5].

  17. Social Support Reciprocity and Occupational Self-Efficacy Beliefs during Mothers' Organizational Re-Entry

    ERIC Educational Resources Information Center

    Jaeckel, Dalit; Seiger, Christine P.; Orth, Ulrich; Wiese, Bettina S.

    2012-01-01

    The present study assesses the effects of a lack of social support reciprocity at work on employees' occupational self-efficacy beliefs. We assume that the self-efficacy effects of received support and support reciprocity depend on the specific work context (e.g., phase in the process of organizational socialization). 297 women who returned to…

  18. Maneuver Analysis and Targeting Strategy for the Stardust Re-Entry Capsule

    NASA Technical Reports Server (NTRS)

    Helfrich, Cliff; Bhat, Ramachand S.; Kangas, Julie A.; Wilson, Roby S.; Wong, Mau C.; Potts, Christopher L.; Williams, Kenneth E.

    2006-01-01

    The Stardust Sample Return Capsule (SRC) returned to Earth on January 15, 2006 after seven years of collecting interstellar and comet particles over three heliocentric revolutions, as shown in Figure 1. The SRC was carried on board the Stardust spacecraft, as shown in Figure 2. Because the spacecraft was built with unbalanced thrusters, turns and attitude control maintenance resulted in undesirable delta-v being imparted to the trajectory. As a result, a carefully planned maneuver strategy was devised to accurately target the Stardust capsule to the Utah Test and Training Range (UTTR). This paper provides an overview of the Stardust spacecraft and mission and describes the maneuver strategy that was employed to achieve the stringent targeting requirements for landing in Utah. In addition, an overview of Stardust maneuver analysis tools and techniques will also be presented.

  19. The HYTHIRM Project: Flight Thermography of the Space Shuttle During the Hypersonic Re-entry

    NASA Technical Reports Server (NTRS)

    Horvath, Thomas J.; Tomek, Deborah M.; Berger, Karen T.; Zalameda, Joseph N.; Splinter, Scott C.; Krasa, Paul W.; Schwartz, Richard J.; Gibson, David M.; Tietjen, Alan B.; Tack, Steve

    2010-01-01

    This report describes a NASA Langley led endeavor sponsored by the NASA Engineering Safety Center, the Space Shuttle Program Office and the NASA Aeronautics Research Mission Directorate to demonstrate a quantitative thermal imaging capability. A background and an overview of several multidisciplinary efforts that culminated in the acquisition of high resolution calibrated infrared imagery of the Space Shuttle during hypervelocity atmospheric entry is presented. The successful collection of thermal data has demonstrated the feasibility of obtaining remote high-resolution infrared imagery during hypersonic flight for the accurate measurement of surface temperature. To maximize science and engineering return, the acquisition of quantitative thermal imagery and capability demonstration was targeted towards three recent Shuttle flights - two of which involved flight experiments flown on Discovery. In coordination with these two Shuttle flight experiments, a US Navy NP-3D aircraft was flown between 26-41 nautical miles below Discovery and remotely monitored surface temperature of the Orbiter at Mach 8.4 (STS-119) and Mach 14.7 (STS-128) using a long-range infrared optical package referred to as Cast Glance. This same Navy aircraft successfully monitored the Orbiter Atlantis traveling at approximately Mach 14.3 during its return from the successful Hubble repair mission (STS-125). The purpose of this paper is to describe the systematic approach used by the Hypersonic Thermodynamic Infrared Measurements team to develop and implement a set of mission planning tools designed to establish confidence in the ability of an imaging platform to reliably acquire, track and return global quantitative surface temperatures of the Shuttle during entry. The mission planning tools included a pre-flight capability to predict the infrared signature of the Shuttle. Such tools permitted optimization of the hardware configuration to increase signal-to-noise and to maximize the available dynamic range while mitigating the potential for saturation. Post flight, analysis tools were used to assess atmospheric effects and to convert the 2-D intensity images to 3-D temperature maps of the windward surface. Comparison of the spatially resolved global thermal measurements to surface thermocouples and CFD prediction is made. Successful demonstration of a quantitative, spatially resolved, global temperature measurement on the Shuttle suggests future applications towards hypersonic flight test programs within NASA, DoD and DARPA along with flight test opportunities supporting NASA's project Constellation.

  20. Megan's Law and its impact on community re-entry for sex offenders.

    PubMed

    Levenson, Jill S; D'Amora, David A; Hern, Andrea L

    2007-01-01

    Community notification, known as "Megan's Law," provides the public with information about known sex offenders in an effort to assist parents and potential victims to protect themselves from dangerous predators. The purpose of this study was to explore the impact of community notification on the lives of registered sex offenders. Two hundred and thirty-nine sex offenders in Connecticut and Indiana were surveyed. The negative consequences that occurred with the greatest frequency included job loss, threats and harassment, property damage, and suffering of household members. A minority of sex offenders reported housing disruption or physical violence following community notification. The majority experienced psychosocial distress such as depression, shame, and hopelessness. Recommendations are made for community notification policies that rely on empirically derived risk assessment classification systems in order to better inform the public about sex offenders' danger while minimizing the obstacles that interfere with successful community reintegration.

  1. GOCE Re-Entry Predictions for the Italian Civil Protection Authorities

    NASA Astrophysics Data System (ADS)

    Pardini, Carmen; Anselmo, Luciano

    2015-03-01

    The uncommon nature of the GOCE reentry campaign, sharing an uncontrolled orbital decay with a finely controlled attitude along the atmospheric drag direction, made the reentry predictions for this satellite an interesting case study, especially because nobody was able to say a priori if and when the attitude control would have failed, leading to an unrestrained tumbling and a sudden variation of the orbital decay rate. As in previous cases, ISTI/CNR was in charge of reentry predictions for the Italian civil protection authorities, monitoring also the satellite decay in the frame of an international reentry campaign promoted by the Inter-Agency Space Debris Coordination Committee (IADC). Due to the peculiar nature of the GOCE reentry, the definition of reliable uncertainty windows was not easy, especially considering the critical use of this information for civil protection evaluations. However, after an initial period of test and analysis, reasonable and conservative criteria were elaborated and applied, with good and consistent results through the end of the reentry campaign. In the last three days of flight, reentries were simulated over Italy to obtain quite accurate ground tracks, debris swaths and air space crossing time windows associated with the critical passes over the national territory still included in the global uncertainty windows.

  2. Promoting the Personal Growth and Vocational Maturity of the Re-entry Woman: A Group Approach.

    ERIC Educational Resources Information Center

    DiNuzzo, Theresa M.; Tolbert, E. L.

    1981-01-01

    Examined the effects of a group counseling model on the vocational maturity, self-esteem and self-confidence, degree of conformity, personal effectiveness and integration, and perception of needs of reentry women. Short-term group career counseling was effective; counselor facilitation and mutual group support promoted positive personal change.…

  3. Institutional, Situational and Dispositional Obstacles Encountered by the Re-entry Graduate Woman.

    ERIC Educational Resources Information Center

    Barkhymer, Meg; Dorsett, Yvonne

    Women who enter college after a significant interruption in their education often face obstacles or barriers that affect their success. These obstacles are typically classified into one of three categories: institutional barriers, situational barriers, or dispositional barriers. This study, conducted with 47 graduate women with a mean age of 34.7…

  4. Atrioventricular Nodal Re-entry Tachycardia in Identical Twins: A Case Report and Literature Review

    PubMed Central

    Barake, Walid; Caldwell, Jane; Baranchuk, Adrian

    2013-01-01

    This report details the case of 17 year old identical twins who both presented with paroxysmal supraventricular tachycardia (PSVT). Electrophysiological studies revealed atrioventricular nodal reentry tachycardia (AVNRT) in both twins. Successful but technically challenging slow pathway ablation was performed in both twins. This is the first reported case of confirmed AVNRT in identical twins which adds strong evidence to heritability of the dual AV node physiology and AVNRT. A review of the current literature regarding PSVT in monozygotic twins is provided. PMID:23329875

  5. A Grounded Theory Study of the Re-Entry Process of Teen Parents' Return to School after Dropping Out

    ERIC Educational Resources Information Center

    Melton, Brenda L.

    2013-01-01

    Without the rich stories of the experiences of teen parents who drop out of school and then re-enter, we do not have a total picture of the dropout phenomenon and how best to address the issues for this marginalized group. Using the research strategies of Charmaz' social constructivist grounded theory, Melton has gathered detailed stories about…

  6. An application utilizing horizontal re-entries versus waterflooding for depleting a mid-life Niagaran Reef

    SciTech Connect

    Pieters, D.A.; Pearce, L.A.

    1996-12-31

    Waterflooding has been the preferred secondary recovery technique for mid-life Michigan Niagaran reefs that were large enough to economically warrant it. Since these pinnacle reefs average 50-550 acres, the success in waterflooding such a limited space has been a hit or miss proposition depending on the pinpoint accuracy in locating injector and producer. This paper presents a case history for the Colfax 25 reef where five horizontal drainholes were positioned across the field in a pattern to access and drain all areas of the reservoir. This particular reef was chosen based on identified incremental reserves, areal extent and on past production history which displayed reservoir characteristics that were favorable for horizontal wells. The application was tremendously successful. Production in all wells doubled as gas oil ratios were significantly reduced. Start-up costs were slightly below those of a conventional water flood and operating costs were substantially lower than would be incurred for a waterflood.

  7. Prediction of electron concentration reductions in re-entry flow fields due to electrophilic liquid and water injection.

    NASA Technical Reports Server (NTRS)

    Pergament, H. S.; Mikatarian, R. R.; Kurzius, S. C.

    1972-01-01

    Discussion of an analytical model which leads to predictions of reductions in electron concentrations in reentry flow fields due to the injection of electrophilic liquids and water. The processes incorporated into the model are: penetration and breakup of the liquid jet, droplet acceleration and vaporization, expansion of the liquid spray due to droplet vaporization, electrophilic vapor diffusion, heterogeneous and homogeneous charged species recombination kinetics and homogeneous electron attachment kinetics. Spray boundary calculations are shown to be in good agreement with photographic observations of water and Freon E-3 sprays in wind tunnel tests of a scale model RAM C-III flight vehicle. Fixed-bias electrostatic probe data taken during the RAM C-III flight are interpreted in terms of effective jet penetration distances - which are shown to be consistent with calculations using the present model.

  8. Re-Entry Analysis Comparison with Different Solar Activity Models of Spent Upper Stage Using ESA's DRAMA Tool

    NASA Astrophysics Data System (ADS)

    David, Emmanuelle; Braun, Vitali

    2013-09-01

    The goal of the paper is to investigate the influence of different methods for solar activity forecasts on the simulation of residual lifetime of upper stages in GTO. For this study the OSCAR software from the ESA DRAMA tool suite was used to perform an orbital decay simulation for an Ariane 4 upper stage (1997-016-C) from 1997 to 2012. As a reference, the orbital decay of the rocket body has been compared to TLE data available from Space-Track. For the simulation, it was possible to select between a best-guess scenario (including best case and worst case scenarios), constant equivalent solar activity, ECSS standard cycle or any user-selected historic cycle and solar activity sampled through a Monte Carlo approach. In addition, the evolution of the orbit has been analysed taking orbit perturbation into account (Drag, Geopotential, Third Bodies effect). Finally a sensitivity on the mass and cross-section area of the upper-stage have been performed in order to understand which parameter may influence the residual life in GTO.

  9. Yeast spore germination: a requirement for Ras protein activity during re-entry into the cell cycle.

    PubMed Central

    Herman, P K; Rine, J

    1997-01-01

    Saccharomyces cerevisiae spore germination is a process in which quiescent, non-dividing spores become competent for mitotic cell division. Using a novel assay for spore uncoating, we found that spore germination was a multi-step process whose nutritional requirements differed from those for mitotic division. Although both processes were controlled by nutrient availability, efficient spore germination occurred in conditions that did not support cell division. In addition, germination did not require many key regulators of cell cycle progression including the cyclin-dependent kinase, Cdc28p. However, two processes essential for cell growth, protein synthesis and signaling through the Ras protein pathway, were required for spore germination. Moreover, increasing Ras protein activity in spores resulted in an accelerated rate of germination and suggested that activation of the Ras pathway was rate-limiting for entry into the germination program. An early step in germination, commitment, was identified as the point at which spores became irreversibly destined to complete the uncoating process even if the original stimulus for germination was removed. Spore commitment to germination required protein synthesis and Ras protein activity; in contrast, post-commitment events did not require ongoing protein synthesis. Altogether, these data suggested a model for Ras function during transitions between periods of quiescence and cell cycle progression. PMID:9321396

  10. Inducing myoblast re-entry into the cell cycle: a potential mechanism for laser-enhanced skeletal muscle regeneration

    NASA Astrophysics Data System (ADS)

    Liu, T.; Fang, Y.; Zhang, C. P.; Chen, P.; Wang, C. Z.; Kang, H. X.; Shen, B. J.; Liang, J.; Fu, X. B.

    2014-09-01

    This study investigated the effect of low-level laser irradiation (LLLI) on the cell cycle and proliferative activity of cultured myoblasts, and sought to elucidate the possible cellular mechanism by which LLLI promotes the regeneration of skeletal muscle in vivo. Primary myoblasts isolated from rat hindlegs were irradiated with helium-neon laser light at different energy densities. Distributions of cell-cycle subpopulations and the expression of cell-cycle regulatory proteins in myoblasts were assessed using flow cytometric analysis and western blot assay. It was found that laser irradiation stimulated cell-cycle entry; induced the expression of cyclin A and cyclin D; and increased cell proliferation index and bromodeoxyuridine incorporation as compared to the unirradiated control cells, indicating LLLI augmented the number of proliferative myoblasts in the S phase and G2/M phase of the cell cycle. These results suggest that LLLI at certain fluxes and wavelengths could activate quiescent myoblasts, leading to cell division and facilitating new myofiber formation. This could contribute to the improvement of skeletal muscle regeneration following trauma and myopathic diseases.

  11. Development of Non-Uniform Radiation Solution Methods for Atmospheric Re-entry Using Detailed Thermal Modeling

    DTIC Science & Technology

    2009-03-01

    measurements , total heating measurements were made with 12 calorimeter plugs arranged along three rays on the windward side of the vehicle [15]. These...Parameter Value Wall Temperature 810 K Free Stream Temp 215 K Mach No. 38.5 Reynolds Number 47426 Free Stream Pressure 5.8 Pa Table 5 Free stream mass...method is compared to the results of the tangent-slab analysis, and with the values measured in the experiment. iv Acknowledgements I’d like to thank Dr

  12. A Grounded Theory Study of the Re-Entry Process of Teen Parents' Return to School after Dropping Out

    ERIC Educational Resources Information Center

    Melton, Brenda L.

    2013-01-01

    Without the rich stories of the experiences of teen parents who drop out of school and then re-enter, we do not have a total picture of the dropout phenomenon and how best to address the issues for this marginalized group. Using the research strategies of Charmaz' social constructivist grounded theory, Melton has gathered detailed stories about…

  13. Histone acetyltransferase HAT4 modulates navigation across G2/M and re-entry into G1 in Leishmania donovani

    PubMed Central

    Yadav, Aarti; Chandra, Udita; Saha, Swati

    2016-01-01

    Histone acetyltransferases impact multiple processes. This study investigates the role of histone acetyltransferase HAT4 in Leishmania donovani. Though HAT4 was dispensable for survival, its elimination decreased cell viability and caused cell cycle defects, with HAT4-nulls experiencing an unusually long G2/M. Survival of HAT4-nulls in macrophages was also substantially compromised. DNA microarray analysis revealed that HAT4 modestly regulated the expression of only a select number of genes, thus not being a major modulator of global gene expression. Significantly, cdc20 was among the downregulated genes. To ascertain if decreased expression of cdc20 was responsible for HAT4-null growth and cell cycle defects we expressed LdCdc20 ectopically in HAT4-nulls. We found this to alleviate the aberrant growth and cell cycle progression patterns displayed by HAT4-nulls, with cells navigating G2/M phase and re-entering G1 phase smoothly. HAT4-nulls expressing LdCdc20 ectopically showed survival rates comparable to wild type within macrophages, suggesting that G2/M defects were responsible for poor survival of HAT4-nulls within host cells also. These are the first data analyzing the in vivo functional role of HAT4 in any trypanosomatid. Our results directly demonstrate for the first time a role for Cdc20 in regulating trypanosomatid G2/M events, opening avenues for further research in this area. PMID:27272906

  14. Heber D. Curtis: The Re-entry Graduate Student at UVa Who Became an Outstanding Dynamical Astronomer

    NASA Astrophysics Data System (ADS)

    Osterbrock, D. E.

    1998-09-01

    Heber D. Curtis, the great pioneer of nebular and galactic research, later observatory director at Allegheny and then at the University of Michigan, was a dynamical astronomer in the earliest days of photographic radial-velocity measurements. He did his undergraduate work in classical languages at Michigan, where as a student he showed no apparent interest in astronomy. Curtis's first jobs were teaching Latin and Greek at Napa College, then at the College of the Pacific. Both had small Clark refractors and he began observing, then measuring, visual double stars. He decided to become an astronomer, and spent the summers of 1897 and 1898 as a special student at Lick Observatory, and of 1899 at Ann Arbor. In 1900, at the age of 28, married and with two small children, Curtis entered the University of Virginia as a full-time graduate student. Both Yerkes and Lick Observatories had declined to accept him. At Charlottesville Curtis did his Ph.D. thesis on the orbit of Comet 1898 I, received his degree in 1902, and immediately joined the Lick staff. His work on spectroscopic binaries and high-velocity stars at Mount Hamilton and at the Lick Southern Hemisphere Observatory, will be described in this paper. W. W. Campbell and Curtis published the First Catalogue of Spectroscopic Binaries in 1905; it listed all 140 of these objects then known. In 1909, Curtis was recalled to Lick to take over the Crossley reflector and thus left the field of dynamical astronomy. At Santiago, his assistant was George F. Paddock, a UVa M.A. in astronomy who based his Ph.D. thesis on Chile observational data. When Ormond Stone, UVa professor of astronomy and Leander McCormick Observatory director, retired in 1912, Curtis was the first choice to succeed him, but declined the post to remain at Lick.

  15. An electromagnetic method for removing the communication blackout with a space vehicle upon re-entry into the atmosphere

    NASA Astrophysics Data System (ADS)

    Cheng, Jianjun; Jin, Ke; Kou, Yong; Hu, Ruifeng; Zheng, Xiaojing

    2017-03-01

    When a hypersonic vehicle travels in the Earth and Mars atmosphere, the surface of the vehicle is surrounded by a plasma layer, which is an envelope of ionized air, created from the compression and heat of the atmosphere by the shock wave. The vehicles will lose contact with ground stations known as the reentry communication blackout. Based on the magnetohydrodynamic framework and electromagnetic wave propagation theory, an analytical model is proposed to describe the effect of the effectiveness of electromagnetic mitigation scheme on removing the reentry communication blackout. C and Global Positioning System (GPS) bands, two commonly used radio bands for communication, are taken as the cases to discuss the effectiveness of the electromagnetic field mitigation scheme. The results show that the electron density near the antenna of vehicles can be reduced by the electromagnetic field, and the required external magnetic field strength is far below the one in the magnetic window method. The directions of the external electric field and magnetic field have a significant impact on the effectiveness of the mitigation scheme. Furthermore, the effect of electron collisions on the required applied electromagnetic field is discussed, and the result indicates that electron collisions are a key factor to analyze the electromagnetic mitigation scheme. Finally, the feasible regions of the applied electromagnetic field for eliminating blackout are given. These investigations could have a significant benefit on the design and optimization of electromagnetic mitigation scheme for the blackout problem.

  16. High-G testing of MEMS mechanical non-volatile memory and silicon re-entry switch.

    SciTech Connect

    Baker, Michael Sean; Pohl, Kenneth Roy

    2005-10-01

    Two different Sandia MEMS devices have been tested in a high-g environment to determine their performance and survivability. The first test was performed using a drop-table to produce a peak acceleration load of 1792 g's over a period of 1.5 ms. For the second test the MEMS devices were assembled in a gun-fired penetrator and shot into a cement target at the Army Waterways Experiment Station in Vicksburg Mississippi. This test resulted in a peak acceleration of 7191 g's for a duration of 5.5 ms. The MEMS devices were instrumented using the MEMS Diagnostic Extraction System (MDES), which is capable of driving the devices and recording the device output data during the high-g event, providing in-flight data to assess the device performance. A total of six devices were monitored during the experiments, four mechanical non-volatile memory devices (MNVM) and two Silicon Reentry Switches (SiRES). All six devices functioned properly before, during, and after each high-g test without a single failure. This is the first known test under flight conditions of an active, powered MEMS device at Sandia.

  17. Potential of glassy carbon and silicon carbide photonic structures as electromagnetic radiation shields for atmospheric re-entry.

    PubMed

    Komarevskiy, Nikolay; Shklover, Valery; Braginsky, Leonid; Hafner, Christian; Lawson, John

    2012-06-18

    During high-velocity atmospheric entries, space vehicles can be exposed to strong electromagnetic radiation from ionized gas in the shock layer. Glassy carbon (GC) and silicon carbide (SiC) are candidate thermal protection materials due to their high melting point and also their good thermal and mechanical properties. Based on data from shock tube experiments, a significant fraction of radiation at hypersonic entry conditions is in the frequency range from 215 to 415 THz. We propose and analyze SiC and GC photonic structures to increase the reflection of radiation in that range. For this purpose, we performed numerical optimizations of various structures using an evolutionary strategy. Among the considered structures are layered, porous, woodpile, inverse opal and guided-mode resonance structures. In order to estimate the impact of fabrication inaccuracies, the sensitivity of the reflectivity to structural imperfections is analyzed. We estimate that the reflectivity of GC photonic structures is limited to 38% in the aforementioned range, due to material absorption. However, GC material can be effective for photonic reflection of individual, strong spectral line. SiC on the other hand can be used to design a good reflector for the entire frequency range.

  18. Potential of Glassy Carbon and Silicon Carbide Photonic Structures as Electromagnetic Radiation Shields for Atmospheric Re-entry

    NASA Technical Reports Server (NTRS)

    Komarevskiy,Nikolay; Shklover, Valery; Braginsky, Leonid; Hafner, Christian; Lawson, John W.

    2012-01-01

    During high-velocity atmospheric entries, space vehicles can be exposed to strong electromagnetic radiation from ionized gas in the shock layer. Glassy carbon (GC) and silicon carbide (SiC) are candidate thermal protection materials due to their high melting point and also their good thermal and mechanical properties. Based on data from shock tube experiments, a significant fraction of radiation at hypersonic entry conditions is in the frequency range from 215 to 415 THz. We propose and analyze SiC and GC photonic structures to increase the reflection of radiation in that range. For this purpose, we performed numerical optimizations of various structures using an evolutionary strategy. Among the considered structures are layered, porous, woodpile, inverse opal and guided-mode resonance structures. In order to estimate the impact of fabrication inaccuracies, the sensitivity of the reflectivity to structural imperfections is analyzed. We estimate that the reflectivity of GC photonic structures is limited to 38% in the aforementioned range, due to material absorption. However, GC material can be effective for photonic reflection of individual, strong spectral line. SiC on the other hand can be used to design a good reflector for the entire frequency range.

  19. Quantum Scattering Study of Ro-Vibrational Excitations in N+N(sub 2) Collisions under Re-entry Conditions

    NASA Technical Reports Server (NTRS)

    Wang, Dunyou; Stallcop, James R.; Dateo, Christopher E.; Schwenke, David W.; Huo, Winifred M.

    2004-01-01

    A three-dimensional time-dependent quantum dynamics approach using a recently developed ab initio potential energy surface is applied to study ro-vibrational excitation in N+N2 exchange scattering for collision energies in the range 2.1- 3.2 eV. State-to-state integral exchange cross sections are examined to determine the distribution of excited rotational states of N(sub 2). The results demonstrate that highly-excited rotational states are produced by exchange scattering and furthermore, that the maximum value of (Delta)j increases rapidly with increasing collision energies. Integral exchange cross sections and exchange rate constants for excitation to the lower (upsilon = 0-3) vibrational energy levels are presented as a function of the collision energy. Excited-vibrational-state distributions for temperatures at 2,000 K and 10,000 K are included.

  20. Body surface mapping of retrograde P waves in the intact dog by simulation of accessory pathway re-entry.

    PubMed

    Pintér, A; Molin, F; Savard, P; Tremblay, G; Sierra, G; Nadeau, R

    2000-02-01

    To investigate a noninvasive technique to localize the atrial insertion site of concealed accessory pathways based on the analysis of body surface potential maps (BSPMs) of retrograde P waves in dogs with simulated retrograde pathways. Orthodromic tachycardias were simulated by atrial stimulations at eight different sites around the atrioventricular ring with long (250 ms and 300 ms) and short (100 ms and 130 ms) coupling times in 14 anesthetized dogs to have P waves well separated from the T wave or occurring during the T wave, respectively. The distance between pacing sites was 15 to 40 mm in group 1 (eight dogs) and 2 mm (in the right atrial free wall region) in group 2 (six dogs). Beats were signal-averaged during 30 s and BSPMs were constructed from 63 unipolar leads. The P wave BSPM pattern for any specific stimulation site was stable and reproducible (correlation coefficient greater than 0.98), and similar in different dogs at long coupling interval stimulations. The thoracic distribution of negative potentials and position of the potential minimum clearly identified the stimulation site when long coupling time stimulations were used. The spatial resolution of the technique as determined by comparison of correlation coefficients in group 2 was 6 mm (P<0.05). When short coupling time stimulations were used (fast tachycardia simulation), the T wave masked the P wave potential distribution in four of eight dogs, but the retrograde P wave map could still be accurately extracted by subtracting a straight line joining the onset and offset of the P wave in 24 of 28 (86%) of the tachycardia simulation sites in these four dogs. The BSPM patterns of simulated retrograde P waves are specifically related to the site of atrial stimulation. Although the T wave altered these BSPM patterns, a subtraction technique recovered the pattern of the retrograde P wave in 93% of all simulated orthodromic tachycardias. The spatial resolution of the retrograde P wave BSPM method was 6 mm.

  1. HYTHIRM Radiance Modeling and Image Analyses in Support of STS-119, STS-125 and STS-128 Space Shuttle Hypersonic Re-entries

    NASA Technical Reports Server (NTRS)

    Gibson, David M.; Spisz, Thomas S.; Taylor, Jeff C.; Zalameda, Joseph N.; Horvath, Thomas J.; Tomek, Deborah M.; Tietjen, Alan B.; Tack, Steve; Bush, Brett C.

    2010-01-01

    We provide the first geometrically accurate (i.e., 3-D) temperature maps of the entire windward surface of the Space Shuttle during hypersonic reentry. To accomplish this task we began with estimated surface temperatures derived from CFD models at integral high Mach numbers and used them, the Shuttle's surface properties and reasonable estimates of the sensor-to-target geometry to predict the emitted spectral radiance from the surface (in units of W sr-1 m-2 nm-1). These data were converted to sensor counts using properties of the sensor (e.g. aperture, spectral band, and various efficiencies), the expected background, and the atmosphere transmission to inform the optimal settings for the near-infrared and midwave IR cameras on the Cast Glance aircraft. Once these data were collected, calibrated, edited, registered and co-added we formed both 2-D maps of the scene in the above units and 3-D maps of the bottom surface in temperature that could be compared with not only the initial inputs but also thermocouple data from the Shuttle itself. The 3-D temperature mapping process was based on the initial radiance modeling process. Here temperatures were guessed for each node in a well-resolved 3-D framework, a radiance model was produced and compared to the processed imagery, and corrections to the temperature were estimated until the iterative process converged. This process did very well in characterizing the temperature structure of the large asymmetric boundary layer transition the covered much of the starboard bottom surface of STS-119 Discovery. Both internally estimated accuracies and differences with CFD models and thermocouple measurements are at most a few percent. The technique did less well characterizing the temperature structure of the turbulent wedge behind the trip due to limitations in understanding the true sensor resolution. (Note: Those less inclined to read the entire paper are encouraged to read an Executive Summary provided at the end.)

  2. Correctional Education and the Reduction of Recidivism: A Quantitative Study of Offenders' Educational Attainment and Success upon Re-Entry into Society

    ERIC Educational Resources Information Center

    Tanguay, Daniel T.

    2014-01-01

    Research has shown correctional education has always been associated with prison reform from the early years of Pennsylvania's Eastern State Penitentiary to the modern correctional systems of today. However, as a result of increased prison populations and costs, correctional education leadership has been challenged to validate the need for these…

  3. Biomaterial bridges enable regeneration and re-entry of corticospinal tract axons into the caudal spinal cord after SCI: Association with recovery of forelimb function.

    PubMed

    Pawar, Kiran; Cummings, Brian J; Thomas, Aline; Shea, Lonnie D; Levine, Ariel; Pfaff, Sam; Anderson, Aileen J

    2015-10-01

    Severed axon tracts fail to exhibit robust or spontaneous regeneration after spinal cord injury (SCI). Regeneration failure reflects a combination of factors, including the growth state of neuronal cell bodies and the regeneration-inhibitory environment of the central nervous system. However, while spared circuitry can be retrained, target reinnervation depends on longitudinally directed regeneration of transected axons. This study describes a biodegradable implant using poly(lactide-co-glycolide) (PLG) bridges as a carrier scaffold to support regeneration after injury. In order to detect regeneration of descending neuronal tracts into the bridge, and beyond into intact caudal parenchyma, we developed a mouse cervical implantation model and employed Crym:GFP transgenic mice. Characterization of Crym:GFP mice revealed that descending tracts, including the corticospinal tract, were labeled by green fluorescent protein (GFP), while ascending sensory neurons and fibers were not. Robust co-localization between GFP and neurofilament-200 (NF-200) as well as GFP and GAP-43 was observed at both the rostral and caudal bridge/tissue interface. No evidence of similar regeneration was observed in mice that received gelfoam at the lesion site as controls. Minimal co-localization between GFP reporter labeling and macrophage markers was observed. Taken together, these data suggest that axons originating from descending fiber tracts regenerated, entered into the PLG bridge at the rostral margin, continued through the bridge site, and exited to re-enter host tissue at the caudal edge of the intact bridge. Finally, regeneration through implanted bridges was associated with a reduction in ipsilateral forelimb errors on a horizontal ladder task. Published by Elsevier Ltd.

  4. Optimisation and thermal control of a multi-layered structure for space electronic devices and thermal shielding of re-entry vehicles

    NASA Astrophysics Data System (ADS)

    Monti, Riccardo; Barboni, Renato; Gasbarri, Paolo; Chiwiacowsky, Leonardo D.

    2012-06-01

    All electronic devices, due to Joule effect, present heat dissipation, when they are electrically fed. The heat overstocking produces efficiency and performances reduction. On account of this the thermal control is mandatory. On small electronic equipments, the difficulty or impossibility of using a cooling fluid for the free or forced convection heat dissipation imposes the presence of cooling systems based on another kind of functioning principle such as the conduction. In this paper the thermal control, via pyroelectric materials, is presented. Furthermore, an optimisation of geometric, thermal and mechanical parameters, influencing the thermal dissipation, is studied and presented. Pyroelectric materials are able to convert heat into electrical charge spontaneously and, due to this capability, such materials could represent a suitable choice to increase the heat dissipation. The obtained electric charge or voltage could be used to charge a battery or to feed other equipments. In particular, a sequence of different materials such as Kovar®, molybdenum or copper-tungsten, used in a multi-layer pyroelectric wafer, together with their thicknesses, are design features to be optimised in order to have the optimal thermal dissipation. The optimisation process is performed by a hybrid approach where a genetic algorithm (GA) is used coupled with a local search procedure, in order to provide an appropriate balance between exploration and exploitation of the search space, which helps in the search for the optimal or quasi-optimal solution. Since the design variables used in the optimisation procedure are defined in different domains, discrete (e.g. the number of layers in the pyroelectric wafer) and continuous (e.g. the layers thickness) domains, the genetic representation for the solution should take it into account. The chromosome used in the genetic algorithm will mix both integer and real values, what will also be reflected in the genetic operators used in the optimisation process. Finally, numerical analyses and results complete the work.

  5. Correctional Education and the Reduction of Recidivism: A Quantitative Study of Offenders' Educational Attainment and Success upon Re-Entry into Society

    ERIC Educational Resources Information Center

    Tanguay, Daniel T.

    2014-01-01

    Research has shown correctional education has always been associated with prison reform from the early years of Pennsylvania's Eastern State Penitentiary to the modern correctional systems of today. However, as a result of increased prison populations and costs, correctional education leadership has been challenged to validate the need for these…

  6. Lay-out of a re-usable re-entry vehicle required in a future European low earth orbit scenario

    NASA Astrophysics Data System (ADS)

    Uebelhack, H. T.; Fave, J.

    1984-10-01

    The design concept of a reusable unmanned semiballistic-reentry spacecraft to provide raw materials and return processed materials from a European automated space production facility in LEO is presented and illustrated with drawings, diagrams, graphs, and tables of parameters. A typical mission scenario includes Ariane launch; rendezvous and docking for sample exchange; center-of-mass trimming by adjustment of the load after dedocking; updating of inertial systems; deorbiting to a ballistic arc by means of four 400-N thrusters; atmospheric flight from 100-km altitude at path angle 4 deg, lift/drag ratio 0.2, and maximum deceleration 5 g; and final deceleration and landing using three-stage drogue and main-parachutes, an air-bag system, and landing gears.

  7. Side-Branch and Coaxial Intravascular Ultrasound Guided Wire Re-Entry after Failed Retrograde Approach of Chronic Total Occlusion Intervention

    PubMed Central

    Chou, Ruey-Hsing; Lai, Chih-Hung; Lu, Tse-Min

    2016-01-01

    Intravascular ultrasound (IVUS) can provide valuable information during the intervention of difficult chronic total occlusion (CTO) lesion. Stumpless CTO lesions with an adjacent side branch are associated with a significantly lower success rate because the proper entry point is not always clearly identified and the guidewires easily slip into the side branch. Herein we presented a case of a stumpless middle left circumflex (LCX) artery CTO lesion with auto-collateral from obtuse marginal branch. Initially, we positioned the IVUS into the side-branch to find the entry point of LCX-CTO lesion. However, the punctured wire went into the false lumen. A retrograde approach was tried but later failed. Therefore, we used IVUS to find the entry point where the true lumen transited to the false lumen, and used a stiff guidewire to puncture the entry point. After we confirmed with IVUS that the whole guidewire was in the true lumen, we deployed 3 drug-eluting stents. The final angiogram showed TIMI 3 flow with preservation of all side branches. The patient was angina-free during the 6-month follow-up. By presenting this case, we have demonstrated the application of both side-branch and coaxial IVUS-guided recanalization technique in the stumpless CTO lesion. PMID:27274179

  8. Novel non-invasive algorithm to identify the origins of re-entry and ectopic foci in the atria from 64-lead ECGs: A computational study

    PubMed Central

    Langley, Philip

    2017-01-01

    Atrial tachy-arrhytmias, such as atrial fibrillation (AF), are characterised by irregular electrical activity in the atria, generally associated with erratic excitation underlain by re-entrant scroll waves, fibrillatory conduction of multiple wavelets or rapid focal activity. Epidemiological studies have shown an increase in AF prevalence in the developed world associated with an ageing society, highlighting the need for effective treatment options. Catheter ablation therapy, commonly used in the treatment of AF, requires spatial information on atrial electrical excitation. The standard 12-lead electrocardiogram (ECG) provides a method for non-invasive identification of the presence of arrhythmia, due to irregularity in the ECG signal associated with atrial activation compared to sinus rhythm, but has limitations in providing specific spatial information. There is therefore a pressing need to develop novel methods to identify and locate the origin of arrhythmic excitation. Invasive methods provide direct information on atrial activity, but may induce clinical complications. Non-invasive methods avoid such complications, but their development presents a greater challenge due to the non-direct nature of monitoring. Algorithms based on the ECG signals in multiple leads (e.g. a 64-lead vest) may provide a viable approach. In this study, we used a biophysically detailed model of the human atria and torso to investigate the correlation between the morphology of the ECG signals from a 64-lead vest and the location of the origin of rapid atrial excitation arising from rapid focal activity and/or re-entrant scroll waves. A focus-location algorithm was then constructed from this correlation. The algorithm had success rates of 93% and 76% for correctly identifying the origin of focal and re-entrant excitation with a spatial resolution of 40 mm, respectively. The general approach allows its application to any multi-lead ECG system. This represents a significant extension to our previously developed algorithms to predict the AF origins in association with focal activities. PMID:28253254

  9. Women's Perception of Their Psychological and Practical Needs Upon Re-entry to a Community College: Implications for Restructuring the Learning Environment.

    ERIC Educational Resources Information Center

    Richards, Lillian S.

    This study describes the special needs of women returning to school after an interruption for marriage or employment. One hundred-fifty questionnaires were distributed during 1975 at Fresno City College in California; 90 were returned, of which 82 were usable. Eight problems, in order of importance, identified by returning women were: shortage of…

  10. Where is Merlin When I Need Him? The Barriers to Higher Education are Still in Place: Recent Re-Entry Experience

    ERIC Educational Resources Information Center

    Colvin, Benie B.

    2013-01-01

    While the GI bill after WWII encouraged education for the older students, the combination of baby boomers and the rise of feminism have prompted a new wave of returning students to academia. The nontraditional student since the 1970s has often been an older female returning for a graduate degree. Making the decision to return has not been easy,…

  11. Experiment lithopanspermia: test of interplanetary transfer and re-entry process of epi- and endolithic microbial communities in the FOTON-M3 Mission

    NASA Astrophysics Data System (ADS)

    de La Torre Noetzel, Rosa

    The Lithopanspermia hypothesis assumes that impact-expelled rocks serve as interplanetary transfer vehicles for microorganisms colonizing those rocks. It requires that the microorganisms survive (1) the impact ejection process from the planet of origin; (2) travelling through space; (3) capture and landing on another planet. In the experiment "Lithopanspermia" on board of the FOTON-M3 satellite (14.09.07) steps 2 and 3 of this scenario have been experimentally tested. Assay systems for step 2 were the bipolar epilithic lichen species Rhizocarpon geographicum and Xanthoria elegans on their natural rock substrate as well as their reproduction structures, microbial communities from atacamás halites Chroococcidiopsiss, endolithic communities of Anabaena and Nostoc, and the vagrant lichen species Aspicilia fruticulosa. The samples were exposed to outer space conditions within the BIOPAN-6 facility of ESA. Preparatory space simulation studies (UV solar spectrum radiation and vacuum at 10-2 Pa) performed at the Spasolab-Laboratory of INTA (March-April 2007), have demonstrated the suitability of those lichen species. After flight (10 days exposure to harsh space conditions in low Earth orbit at about 300 km altitude) and recovery, the survival capacity of the microbial communities has been assayed. First analyses have confirmed a fast recovery of the biological activity (chlorophyll a- fluorescence) of the lichens, similar to the high survival rates observed in the experiment LICHENS onboard of the Foton-M2 mission (de la Torre et al., 2007; Sancho et al., 2007). There were no significant changes in relation with the pre-flight values of the epilithic-, endolithicand vagrant lichen samples. First results of Confocal Scanning Laser Microscopy have demonstrated a high vitality of epilithic samples. Ultrastructural changes are being analyzed by Transmission Electron Microscopy and Cryoscanning. Furthermore, concerning the germination capacity of ascospores of Xanthoria elegans up to now no differences were detected between the controls (90 References: De la Torre et al. (2007) BIOPAN experiment LICHENS on the Foton-M2 mission: pre-flight verification tests of the Rhizocarpon geographicum-granite ecosystem, Adv. Space Res. 40, 1665-1671, doi:10.1016/jasr.2007.02.022. Sancho L. et al. (2007) Lichens survive in space. Astrobiology, 7, 443-454. St¨ffler D, et al. (2007) Experimental evidence for the o potential impact ejection of viable microorganisms from Mars and Mars-like planets Icarus, 186, 585-588. Horneck et al. (2007) Microbial rock inhabitants survive hypervelocity impacts on Mars-like host planets: First phase of Lithopanspermia experimentally tested, Astrobiology, in press.

  12. Biomaterial bridges enable regeneration and re-entry of corticospinal tract axons into the caudal spinal cord after SCI: association with recovery of forelimb function

    PubMed Central

    Pawar, Kiran; Cummings, Brian J.; Thomas, Aline; Shea, Lonnie D.; Levine, Ariel; Pfaff, Sam; Anderson, Aileen J.

    2015-01-01

    Severed axon tracts fail to exhibit robust or spontaneous regeneration after spinal cord injury (SCI). Regeneration failure reflects a combination of factors, including the growth state of neuronal cell bodies and the regeneration-inhibitory environment of the central nervous system. However, while spared circuitry can be retrained, target reinnervation depends on longitudinally directed regeneration of transected axons. This study describes a biodegradable implant using poly(lactideco-glycolide) (PLG) bridges as a carrier scaffold to support regeneration after injury. In order to detect regeneration of descending neuronal tracts into the bridge, and beyond into intact caudal parenchyma, we developed a mouse cervical implantation model and employed Crym:GFP transgenic mice. Characterization of Crym:GFP mice revealed that descending tracts, including the corticospinal tract, were labeled by green fluorescent protein (GFP), while ascending sensory neurons and fibers were not. Robust co-localization between GFP and neurofilament-200 (NF-200) as well as GFP and GAP-43 was observed at both the rostral and caudal bridge/tissue interface. No evidence of similar regeneration was observed in mice that received gelfoam at the lesion site as controls. Minimal co-localization between GFP reporter labeling and macrophage markers was observed. Taken together, these data suggest that axons originating from descending fiber tracts regenerated, entered into the PLG bridge at the rostral margin, continued through the bridge site, and exited to re-enter host tissue at the caudal edge of the intact bridge. Finally, regeneration through implanted bridges was associated with a reduction in ipsilateral forelimb errors on a horizontal ladder task. PMID:26134079

  13. A new release of the mean orbital motion theory, and a new tool provided by CNES for long term analysis of disposal orbits and re-entry predictions

    NASA Astrophysics Data System (ADS)

    Deleflie, Florent; Wailliez, Sébastien; Portmann, Christophe; Gilles, M.; Vienne, Alain; Berthier, J.; Valk, St; Hautesserres, Denis; Martin, Thierry; Fraysse, Hubert

    To perform an orbit modelling accurate enough to provide a good estimate of the lifetime of a satellite, or to ensure the stability of a disposal orbit through centuries, we built a new orbit propagator based on the theory of mean orbital motion. It is named SECS-SD2 , for Simplified and Extended CODIOR Software -Space Debris Dedicated . The CODIOR software propagates numerically averaged equations of motion, with a typical integration step size on the order of a few hours, and was originally written in classical orbital elements. The so-called Space Debris -dedicated version is written in orbital elements suitable for orbits with small eccentricities and inclinations, so as to characterize the main dynamic properties of the motion within the LEO, MEO, and GEO regions. The orbital modelling accounts for the very first terms of the geopotential, the perturbations induced by the luni-solar attraction, the solar radiation pressure, and the atmospheric drag (using classical models). The new software was designed so as to ensure short computation times, even over periods of decades or centuries. This paper aims first at describing and validating the main functionalities of the software: we explain how the simplified averaged equations of motion were built, we show how we get sim-plified luni-solar ephemerides without using any huge file for orbit propagations over centuries, and we show how we averaged and simulated the solar flux. We show as well how we expressed short periodic terms to be added to the mean equations of motion, in order to get orbital ele-ments comparable to those deduced from the classical numerical integration of the oscultating equations of motion. The second part of the paper sheds light on some dynamical properties of space debris flying in the LEO and GEO regions, which were obtained from the new software. Knowing that each satellite in the LEO region is now supposed to re-enter the atmosphere within a period of 25 years, we estimated in various dynamical configurations the lifetime of LEO objects depending on their initial conditions of motion, on the solar flux models applied through decades, and on the atmospheric density models and also the satellite area-to-mass ratio. In the GEO region, we investigated the dynamical reasons that can cause space debris re-entering the GEO-protected region after the passivation of a disposal spacecraft.

  14. Roundtable on Constructing and Coping with Incarceration and Family Re-Entry: Perspectives from the Field (Philadelphia, Pennsylvania, November 15-16, 2001). Fathers and Families Second-Tier Roundtable Series.

    ERIC Educational Resources Information Center

    Pennsylvania Univ., Philadelphia. National Center on Fathers and Families.

    Issues of incarceration and its effects on parents, children, families, and communities are as much human development concerns as policy dilemmas. This report synthesizes the discussion of these concerns and their implications for policy, practice, and research as presented at the National Center on Fathers and Families'"Roundtable on…

  15. Locking Nut with Stress-Distributing Insert

    NASA Technical Reports Server (NTRS)

    Daniels, Christopher C.

    2010-01-01

    Reusable holders have been devised for evaluating high-temperature, plasma-resistant re-entry materials, especially fabrics. Typical material samples tested support thermal-protection-system damage repair requiring evaluation prior to re-entry into terrestrial atmosphere. These tests allow evaluation of each material to withstand the most severe predicted re-entry conditions.

  16. Adaptable Holders for Arc-Jet Screening Candidate Thermal Protection System Repair Materials

    NASA Technical Reports Server (NTRS)

    Riccio, Joe; Milhoan, Jim D.

    2010-01-01

    Reusable holders have been devised for evaluating high-temperature, plasma-resistant re-entry materials, especially fabrics. Typical material samples tested support thermal-protection-system damage repair requiring evaluation prior to re-entry into terrestrial atmosphere. These tests allow evaluation of each material to withstand the most severe predicted re-entry conditions.

  17. STONE 6: Artificial Sedimentary Meteorites in Space

    NASA Astrophysics Data System (ADS)

    Westall, F.; Demets, R.; Brandstetter, F.; Edwards, H. G. M.; Cockell, C. S.; Parnell, J.; Pillinger, J.; Sancisi-Frey, S.; Franchi, I. A.; Kurat, G.; Brack, A.

    2008-03-01

    The STONE 6 experiment demonstrated the survivability of carbonaceous and microfossiliferous martian analogue sediments during atmospheric re-entry. Doped endoliths died but their carbonised cells remained.

  18. The Use of Interest Inventories with the Re-Entering Woman.

    ERIC Educational Resources Information Center

    Verheyden-Hilliard, Mary Ellen

    The study, a literature review, examines the critical factors affecting re-entry women's access to jobs and their chances of obtaining and retaining work at a level appropriate to their capacities. An examination of the re-entry woman deals with socialization and self-concept, changing attitudes, and new expectations. Bias against women among the…

  19. PIRATES: A Program for Offenders Transitioning into the World of Work

    ERIC Educational Resources Information Center

    Musgrove, Kate Racoff; Derzis, Nicholas C.; Shippen, Margaret E.; Brigman, Holly E.

    2012-01-01

    The study assessed the effectiveness of the Preparing Inmates for Re-Entry through Assistance, Training, and Employment Skills (PIRATES) group, which focused on improving dysfunctional career thoughts. Participants were male offenders (n = 14) enrolled in a re-entry training class. Results showed a statistically significant decrease in…

  20. Advanced Concept

    NASA Image and Video Library

    2008-02-15

    THIS IS A MODEL TEST OF THE 1ST STAGE RE-ENTRY. HEAT TESTING OF A 3% MODEL TO SUPPORT THE ARES/CLV FIRST STAGE RE-ENTRY. THIS OCCURRED AT ARNOLD AIR FORCE BASE, TENNESSEE IN SUPPORT OF THE CONSTELLATION/ARES PROJECT. THIS IMAGE IS EXTRACTED FROM A HIGH DEFINITION VIDEO FILE AND IS THE HIGHEST RESOLUTION AVAILABLE.

  1. Controlled Hypersonic Flight Air Data System and Flight Instrumentation

    DTIC Science & Technology

    2007-06-01

    strongly on the flight envelope, re-entry trajectory and vehicle structure. Flight envelope and re-entry trajectory influence primarily the sensor...6 3.3 Flight Wind angles and basic considerations...determination the Mach number independence principle can however be used to derive simple analytic expressions. 3.3 Flight Wind angles and basic

  2. ATV reentry

    NASA Image and Video Library

    2012-10-03

    ISS033-E-009232 (3 Oct. 2012) --- This still photo taken by the Expedition 33 crew members aboard the International Space Station shows evidence of the fiery plunge through Earth?s atmosphere and the destructive re-entry of the European Automated Transfer Vehicle-3 (ATV-3) spacecraft, also known as ?Edoardo Amaldi.? The end of the ATV took place over a remote swath of the Pacific Ocean where any surviving debris safely splashed down a short time later, at around 1:30 a.m. (GMT) on Oct. 3, thus concluding the highly successful ATV-3 mission. Aboard the craft during re-entry was the Re Entry Breakup Recorder (REBR), a spacecraft ?black box? designed to gather data on vehicle disintegration during re-entry in order to improve future spacecraft re-entry models.

  3. Maneuvering Aerothermal Technology (MAT) Program. Data Bibliography. Task 2

    DTIC Science & Technology

    1981-03-24

    Blattner, C. J., "Background and Supplementary Data in Support of Boost- Glide Re-entry Vehicle Study Program Plan," (U) MOAC A-096 (AD 344 840), August...to Deflected Control Surfaces," AIAA Journal, February 1964. 6. Uselton, J. C., "Force Test Results on a Series of Boost Glide Re- entry Vehicles at...June 1964 (Secret). 12. "Ninth Tri-Annual Progress Report on Asset," (U) MDAC A-788, June 1964 (Classified). 13. "Boost- Glide Re-Entry Vehicle Study

  4. Parkinson's Disease

    MedlinePlus

    ... Lesch-Nyhan Syndrome Information Page Leukodystrophy Information Page Lipid Storage Diseases Information Page Lipoid Proteinosis Information Page ... Career Awards Fellowships Summer Internships Diversity & Re-Entry Supplements Pre-Application Considerations Apply for Funding New Investigators ...

  5. 15 CFR Appendix 1 to Part 960 - Filing Instructions and Information To Be Included in the Licensing Application

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... perigee); (6) Inclination angle; (7) Orbital period. Sec. IIISpace Segment (1) The name of the system and... disposition involves an atmospheric re-entry the applicant must provide an estimate of the total debris...

  6. 15 CFR Appendix 1 to Part 960 - Filing Instructions and Information To Be Included in the Licensing Application

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... perigee); (6) Inclination angle; (7) Orbital period. Sec. IIISpace Segment (1) The name of the system and... disposition involves an atmospheric re-entry the applicant must provide an estimate of the total debris...

  7. 15 CFR Appendix 1 to Part 960 - Filing Instructions and Information To Be Included in the Licensing Application

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... perigee); (6) Inclination angle; (7) Orbital period. Sec. IIISpace Segment (1) The name of the system and... disposition involves an atmospheric re-entry the applicant must provide an estimate of the total debris...

  8. 15 CFR Appendix 1 to Part 960 - Filing Instructions and Information To Be Included in the Licensing Application

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... perigee); (6) Inclination angle; (7) Orbital period. Sec. IIISpace Segment (1) The name of the system and... disposition involves an atmospheric re-entry the applicant must provide an estimate of the total debris...

  9. The IXV vehicle model identification subsystem: Off-line estimation framework

    NASA Astrophysics Data System (ADS)

    Béjar-Romero, J. A.; Bidaux-Sokolowski, A.; Maina, S.; Preaud, J. P.

    2016-07-01

    The Intermediate eXperimental Vehicle (IXV) is an ESA re-entry technological platform built to verify in-flight the performance of critical re-entry technologies. The successful flight of the IXV provides the key elements to consolidate the knowledge necessary for the development of future European re-entry systems. The exploitation of in-flight data represents a cornerstone for this flying test bench. In this frame the IXV Vehicle Model Identification subsystem, VMI, represents those steps, techniques and algorithms that shall be applied to the collected data in order to improve the prediction capabilities for future design of re-entry vehicles and specifically to: Improve IXV flight dynamics model. Validate aerodynamic prediction methods based on Wind Tunnel Tests, WTT, and Computational Fluid Dynamics, CFD. Validate the vehicle model identification process and tools.

  10. Barth Syndrome (BTHS)

    MedlinePlus

    ... Complications of AIDS Information Page Neurological Complications of Lyme Disease Information Page Neuromyelitis Optica Information Page Neuronal ... Career Awards Fellowships Summer Internships Diversity & Re-Entry Supplements Pre-Application Considerations Apply for Funding New Investigators ...

  11. Tarlov Cysts

    MedlinePlus

    ... Complications of AIDS Information Page Neurological Complications of Lyme Disease Information Page Neuromyelitis Optica Information Page Neuronal ... Career Awards Fellowships Summer Internships Diversity & Re-Entry Supplements Pre-Application Considerations Apply for Funding New Investigators ...

  12. Chase Plane Video Of Historic SpaceX Splashdown

    NASA Image and Video Library

    During the re-entry of SpaceX's Dragon capsule, NASA and the United States Navy flew a P-3 Orion Cast Glance aircraft to capture airborne views of the spacecraft's descent. The aircraft, based at t...

  13. The X-38 V-201 Flap Actuator Mechanism

    NASA Technical Reports Server (NTRS)

    Hagen, Jeff; Moore, Landon; Estes, Jay; Layer, Chris

    2004-01-01

    The X-38 Crew Rescue Vehicle V-201 space flight test article was designed to achieve an aerodynamically controlled re-entry from orbit in part through the use of two body mounted flaps on the lower rear side. These flaps are actuated by an electromechanical system that is partially exposed to the re-entry environment. These actuators are of a novel configuration and are unique in their requirement to function while exposed to re-entry conditions. The authors are not aware of any other vehicle in which a major actuator system was required to function throughout the complete re-entry profile while parts of the actuator were directly exposed to the ambient environment.

  14. The HIAD stands for Hypersonic Inflatable Aerodynamic Decelerato

    NASA Image and Video Library

    2013-05-31

    The HIAD stands for Hypersonic Inflatable Aerodynamic Decelerator, an inflatable spacecraft technology that allows payloads to survive the harsh conditions of atmospheric re-entry. This photo was taken at NASA Langley in Building 1250 when sensors were being applied.

  15. The HIAD stands for Hypersonic Inflatable Aerodynamic Decelerato

    NASA Image and Video Library

    2013-04-25

    The HIAD stands for Hypersonic Inflatable Aerodynamic Decelerator, an inflatable spacecraft technology that allows payloads to survive the harsh conditions of atmospheric re-entry. This photo was taken at NASA Langley in Building 1250 when sensors were being applied.

  16. The success of the ESA Intermediate eXperimental Vehicle program

    NASA Astrophysics Data System (ADS)

    Tumino, G.; Mancuso, S.

    2016-07-01

    The atmospheric re-entry domain has always been considered a cornerstone of a wide range of space applications encompassing the planetary exploration, the sample return, the future launchers, the space planes, the crew and the cargo transportation

  17. Diagrams of Spacecraft Reaction Control System (RCS) Function

    NASA Image and Video Library

    1964-01-13

    S64-03506 (1964) --- Diagrams shows Gemini spacecraft functions of the thrusters in the Gemini spacecraft's re-entry control system. Thrusters may be fired in various combinations to cause yaw, roll and pitch.

  18. Repetitive Motion Disorders

    MedlinePlus

    ... Awards Fellowships Summer Internships Diversity & Re-Entry Supplements Pre-Application Considerations Apply for Funding New Investigators Grant ... Committees Application Support Library Clinical Research Next Steps Pre-Funding: After Review Terms of Award Pre-Award ...

  19. PubMed Central

    DE STEFANO, A.; COSTANTINO, C.; RANDO, D.; GIGLIONE, M.; STAGNO, R.; BENNICI, E.

    2015-01-01

    SUMMARY This prospective study was designed to evaluate the differences between immediate and delayed canal re-entry of otoliths after therapeutic manoeuvres in patients with benign paroxysmal positional vertigo (BPPV). A total of 196 patients with BPPV were visited and 127 matched our inclusion criteria. The mean age was 54.74 years. The horizontal semicircular canal (HSC) was involved in 30 cases and the posterior semicircular canal (PSC) in 97 patients. Patients with hearing loss in the ear affected by BPPV have a more recurrent form, compared to those with normal hearing. An immediate canal re-entry was recorded in 3 patients with HSC BPPV, all with geotropic nystagmus. In 7 patients with PSC BPPV, the immediate canal re-entry was detected and the delayed form was noted in 5 patients. The patients with the delayed canal re-entry underwent more than 2 previous manoeuvres. The canal re-entry was not related to the manoeuvre performed. The timing of the Dix-Hallpike test to verify the resolution of the BPPV had a significant role in immediate canal re-entry. A recurrence in the follow-up at least one month after treatment was recorded in 20 patients and was more frequent in patients that had canal re-entry. The canal re-entry or canal switch is a clinical entity that should be kept in mind of the neurotologist when approaching BPPV patients. It is important to distinguish it from recurrence when delayed and from manoeuvre failure when immediate. The timing of manoeuvre performing, in particular the final verification test after therapeutic sessions, is important to prevent the immediate reflux of particles into canals. PMID:26019396

  20. Development of Fast Deterministic Physically Accurate Solvers for Kinetic Collision Integral for Applications of Near Space Flight and Control Devices

    DTIC Science & Technology

    2015-08-31

    predictive capabilities for modeling spacecraft environments in the near-space regime for re- entry applications and for satellite trajectories presents...modeling spacecraft environments in the near- space regime for re-entry applications and for satellite trajectories presents significant challenges due...distribution unlimited. Page 3 applications as well as for satellite trajectories. Other DoD programs that rely critically on technologies in this

  1. Procedure Planning: Anatomical Determinants of Strategy

    PubMed Central

    Hanratty, Colm; Walsh, Simon

    2014-01-01

    In contemporary practice there are three main methods that can be employed when attempting to open a chronic total occlusion (CTO) of a coronary artery; antegrade or retrograde wire escalation, antegrade dissection re-entry and retrograde dissection re-entry. This editorial will attempt to clarify the anatomical features that can be identified to help when deciding which of these strategies to employ initially and help understand the reasons for this decision. PMID:24694102

  2. STS-61C Mission Insignia

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Columbia, which opened the era of the Space Transportation System with four orbital flight tests, is featured in re-entry in the emblem designed by the STS-61C crew representing the seven team members who manned the vehicle for its seventh STS mission. Gold lettering against black background honors the astronaut crewmembers on the delta pattern surrounding colorful re-entry shock waves, and the payload specialists are honored similarly below the sphere

  3. Development of a Parachute System for Deceleration of Flying Vehicles in Supersonic Regimes

    NASA Astrophysics Data System (ADS)

    Pilyugin, N. N.; Khlebnikov, V. S.

    2010-09-01

    Aerodynamic problems arising during design and development of braking systems for re-entry vehicles are analyzed. Aerodynamic phenomena and laws valid in a supersonic flow around a pair of bodies having different shapes are studied. Results of this research can be used in solving application problems (arrangement and optimization of experiments; design and development of various braking systems for re-entry vehicles moving with supersonic speeds in the atmosphere).

  4. Space Shuttle Projects

    NASA Image and Video Library

    1986-01-01

    Columbia, which opened the era of the Space Transportation System with four orbital flight tests, is featured in re-entry in the emblem designed by the STS-61C crew representing the seven team members who manned the vehicle for its seventh STS mission. Gold lettering against black background honors the astronaut crewmembers on the delta pattern surrounding colorful re-entry shock waves, and the payload specialists are honored similarly below the sphere

  5. Advanced Concept

    NASA Image and Video Library

    2008-02-15

    THIS IS A TEST OF THE 1ST STAGE RE-ENTRY VEHICLE. HEAT TESTING OF A 3% MODEL TO SUPPORT THE ARES/ CLV FIRST STAGE RE-ENTRY. THIS TEST OCCURRED AT ARNOLD AIR FORCE BASE, TENNESSEE. THIS TESTING SUPPORTS THE DEVELOPMENT OF THE CONSTELLATION/ARES PROJECT. THIS IMAGE IS EXTRACTED FROM A HIGH DEFINITION VIDEO FILE AND IS THE HIGHEST RESOLUTION AVAILABLE.

  6. The Foreman: Providing the Program Execution Environment for the National Software Works

    DTIC Science & Technology

    1976-03-31

    standard entry points for its tools. These are an initial entry point (cold start), a standard re-entry point ( warm -9- Foreman Specification...BEGINT00L) =1 -> cold start entry point =2 -> warm start re-entry point =3 -> termination routine entry point =4 -> reserved for expansion =5...qhelp the globa files nee defaultin local spa of differ (although permitted static de desires, (each tim by the Fo tools. parameter 1 NSW

  7. The Prospect of Responsive Spacecraft Using Aeroassisted, Trans-Atmospheric Maneuvers

    DTIC Science & Technology

    2014-06-19

    phase of a lunar -return trajectory. In their paper “Skip Entry Trajectory Planning and Guidance,” Brunner and Lu developed an on-board, closed-loop...planetary model with the inclusion of 2-perturbations, and can be used for both lunar and LEO re-entry.26 As an alternative algorithm, Kluever in...by vehicles such as Apollo. For example, re-entry of the Apollo 10 Command Module from lunar transfer orbit produced a maximum deceleration of

  8. Analysis of Plasma Communication Schemes for Hypersonic Vehicles: Final Report

    DTIC Science & Technology

    2009-02-01

    the ReComm scheme for communications through the plasma sheath surrounding a hypersonic vehicle during re-entry. We demonstrate that the time...physical processes of the ReComm scheme for communications through the plasma sheath surrounding a hypersonic vehicle during re-entry. The ReComm scheme...relation is derived to estimate the plasma heating in the sheath due to plasma waves excited by the antenna. Contents I. Introduction 4 II. Electron

  9. The IXV guidance, navigation and control subsystem: Development, verification and performances

    NASA Astrophysics Data System (ADS)

    Marco, Victor; Contreras, Rafael; Sanchez, Raul; Rodriguez, Guillermo; Serrano, Daniel; Kerr, Murray; Fernandez, Vicente; Haya-Ramos, Rodrigo; Peñin, Luis F.; Ospina, Jose A.; De Zaiacomo, Gabriale; Bejar-Romero, Juan Antonio; Yague, Ricardo; Zaccagnino, Elio; Preaud, Jean-Philippe

    2016-07-01

    The Intermediate eXperimental Vehicle (IXV) [1] is an ESA re-entry lifting body demonstrator built to verify in-flight the performance of critical re-entry technologies. The IXV was launched on February the 11th, 2015, aboard Europe's Vega launcher. The IXV´s flight and successful recovery represents a major step forward with respect to previous European re-entry experience with the Atmospheric Re-entry Demonstrator (ARD) [2], flown in October 1998. The increased in-flight manoeuvrability achieved from the lifting body solution permitted the verification of technologies over a wider re-entry corridor. Among other objectives, which included the characterisation of the re-entry environment through a variety of sensors, special attention was paid to Guidance, Navigation and Control (GNC) aspects, including the guidance algorithms for the lifting body, the use of the inertial measurement unit measurements with GPS updates for navigation, and the flight control by means of aerodynamic flaps and reaction control thrusters. This paper presents the overall Design, Development and Verification logic that has been successfully followed by the GNC and Flight Management (FM) subsystem of the IXV. It also focuses on the interactions between the GNC and the System, Avionics and OBSW development lifecycles and how an integrated and incremental verification process has been implemented by ensuring the maximum representativeness and reuse through all stages.

  10. Reducing variability in short term orbital lifetime prediction

    NASA Astrophysics Data System (ADS)

    Kebschull, Christopher; Flegel, Sven Kevin; Braun, Vitali; Gelhaus, Johannes; Möckel, Marek; Wiedemann, Carsten; Vörsmann, Peter

    2013-04-01

    Within the last year three major re-entries occurred. The satellites UARS, ROSAT and Phobos-Grunt entered Earth's atmosphere with fragments reaching the surface. Due to a number of uncertainties in propagating an object's trajectory the exact place and time of a satellite's re-entry is hard to determine. Major influences when predicting the re-entry time are the changing precision of the available orbital data, the satellite's ballistic coefficient, the activity of the sun which influences the Earth's atmosphere and the underlying quality of the atmospheric model. In this paper a method is presented which can reduce the variability in short-term orbital lifetime prediction induced by fluctuating orbital data accuracies. A re-entry campaign is used as a reference for this purpose. For a window of a few weeks before the re-entry the position data of a synthetic object is disturbed considering different degrees of orbital data errors. As a result different predictions will exist for the generated position data of a given day. Using a regression algorithm on the available data an average position is obtained, which is then used for the orbital lifetime prediction. The effect of this measure is a more consistent prediction of the orbital lifetime. The paper concludes with the comparison of the generated re-entry windows in various test cases for the original and the averaged data.

  11. Characterization of supraventricular tachycardia in infants: clinical and instrumental diagnosis.

    PubMed

    Vignati, G; Annoni, G

    2008-01-01

    Supraventricular tachycardia (SVT) is the most common symptomatic arrhythmias in children. Re-entry tachycardias are the most common form, on the contrary automatic tachycardias are relatively rare. There are four types or re-entry: along anomalous pathway with bi-directional (Wolff-Parkinson-White) or unidirectional conduction, intranodal re-entry, intra-atrial re-entry that is common after surgical procedure, and finally the uncommon sinus node re-entry. Automatic tachycardias may be atrial or junctional. The different types of tachycardia have a different incidence according to the age: in the first year of age re-entry along anomalous pathway is the dominant form, while intranodal reentry becomes common during adolescence. The age at the beginning of tachycardia is important for long term prognosis. When SVT starts in the first months of life it disappears in 80% of cases within the first year of life; on the contrary, if tachycardia starts later spontaneous remission is detected in only 15%-20% of patients. In infancy heart failure is the more common presenting symptom, thereafter palpitations become the principal cause of recognition of SVT. Syncope is reported in about 8% of cases and in another 15% usually neonates and infants, the SVT has an occasional detection. Electrocardiogram (ecg) usually allows the precise diagnosis of various types of SVT, and every effort should be made to record ecg during tachycardia. The parameters that should be evaluated are: heart rate, P wave axis, PR and RP interval, and finally presence or absence of AV block. Short lasting episodes should be difficult to be recorded; in these cases cardio-call and trans-telephonic transmission represent useful techniques to obtain SVT demonstration. Patients with SVT require a complete evaluation with others diagnostic techniques: echocardiogram, Holter monitoring, stress test, that should be chosen according the type of tachycardia. Electrophysiologic evaluation is now rarely performed

  12. Tetrahedral lander

    NASA Technical Reports Server (NTRS)

    Roberts, Michael L. (Inventor)

    1993-01-01

    An apparatus and method is disclosed for decelerating and absorbing impact of a re-entry vehicle suitable for payloads that are relatively light as well as payloads weighing several tons or more. The apparatus includes four inflatable legs displaced equidistantly from each other around a capsule or housing which contains a payload. The legs are inflated at a designated altitude after entering earth's atmosphere to slow the descent of the re-entry vehicle. Connected between each of the four legs are drag inducing surfaces that deploy as the legs inflate. The drag inducing surfaces are triangularly shaped with one such surface being connected between each pair of legs for a total of six drag inducing surfaces. The legs have drag inducing outer surfaces which act to slow the descent of the re-entry vehicle.

  13. Intermediate experimental vehicle, ESA program aerodynamics-aerothermodynamics key technologies for spacecraft design and successful flight

    NASA Astrophysics Data System (ADS)

    Dutheil, Sylvain; Pibarot, Julien; Tran, Dac; Vallee, Jean-Jacques; Tribot, Jean-Pierre

    2016-07-01

    With the aim of placing Europe among the world's space players in the strategic area of atmospheric re-entry, several studies on experimental vehicle concepts and improvements of critical re-entry technologies have paved the way for the flight of an experimental space craft. The successful flight of the Intermediate eXperimental Vehicle (IXV), under ESA's Future Launchers Preparatory Programme (FLPP), is definitively a significant step forward from the Atmospheric Reentry Demonstrator flight (1998), establishing Europe as a key player in this field. The IXV project objectives were the design, development, manufacture and ground and flight verification of an autonomous European lifting and aerodynamically controlled reentry system, which is highly flexible and maneuverable. The paper presents, the role of aerodynamics aerothermodynamics as part of the key technologies for designing an atmospheric re-entry spacecraft and securing a successful flight.

  14. Thermal investigation of nuclear waste disposal in space

    NASA Technical Reports Server (NTRS)

    Wilkinson, C. L.

    1981-01-01

    A thermal analysis has been conducted to determine the allowable size and response of bare and shielded nuclear waste forms in both low earth orbit and at 0.85 astronomical units. Contingency conditions of re-entry with a 45 deg and 60 deg aeroshell are examined as well as re-entry of a spherical shielded waste form. A variety of shielded schemes were examined and the waste form thermal response for each determined. Two optimum configurations were selected. The thermal response of these two shielded waste configurations to indefinite exposure to ground conditions following controlled and uncontrolled re-entry is determined. In all cases the prime criterion is that waste containment must be maintained.

  15. Electrophysiological assessment of amiodarone in treatment of resistant supraventricular arrhythmias.

    PubMed Central

    Rowland, E; Krikler, D M

    1980-01-01

    Oral amiodarone has been used to treat 21 patients with various supraventricular arrhythmias; 13 had Wolff-Parkinson-White syndrome, which was complicated by atrial fibrillation and re-entry atrioventricular tachycardia in four, and re-entry tachycardia alone in the other nine. The remaining eight patients had paroxysmal atrial fibrillation or flutter without pre-excitation. All were refractory to conventional treatment and had undergone intracardiac electrophysiological study. Fifteen have been controlled with amiodarone, this treatment proving most effective in atrial fibrillation or flutter with or without pre-excitation. Amiodarone was successful in only four of the nine patients with re-entry atrioventricular tachycardia. In two patients who responded well the drug had to be discontinued because of side effects. Images PMID:7426165

  16. Thermal investigation of nuclear waste disposal in space

    NASA Technical Reports Server (NTRS)

    Wilkinson, C. L.

    1981-01-01

    A thermal analysis has been conducted to determine the allowable size and response of bare and shielded nuclear waste forms in both low earth orbit and at 0.85 astronomical units. Contingency conditions of re-entry with a 45 deg and 60 deg aeroshell are examined as well as re-entry of a spherical shielded waste form. A variety of shielded schemes were examined and the waste form thermal response for each determined. Two optimum configurations were selected. The thermal response of these two shielded waste configurations to indefinite exposure to ground conditions following controlled and uncontrolled re-entry is determined. In all cases the prime criterion is that waste containment must be maintained.

  17. Advances in Procedural Techniques - Antegrade

    PubMed Central

    Wilson, William; Spratt, James C.

    2014-01-01

    There have been many technological advances in antegrade CTO PCI, but perhaps most importantly has been the evolution of the “hybrid’ approach where ideally there exists a seamless interplay of antegrade wiring, antegrade dissection re-entry and retrograde approaches as dictated by procedural factors. Antegrade wire escalation with intimal tracking remains the preferred initial strategy in short CTOs without proximal cap ambiguity. More complex CTOs, however, usually require either a retrograde or an antegrade dissection re-entry approach, or both. Antegrade dissection re-entry is well suited to long occlusions where there is a healthy distal vessel and limited “interventional” collaterals. Early use of a dissection re-entry strategy will increase success rates, reduce complications, and minimise radiation exposure, contrast use as well as procedural times. Antegrade dissection can be achieved with a knuckle wire technique or the CrossBoss catheter whilst re-entry will be achieved in the most reproducible and reliable fashion by the Stingray balloon/wire. It should be avoided where there is potential for loss of large side branches. It remains to be seen whether use of newer dissection re-entry strategies will be associated with lower restenosis rates compared with the more uncontrolled subintimal tracking strategies such as STAR and whether stent insertion in the subintimal space is associated with higher rates of late stent malapposition and stent thrombosis. It is to be hoped that the algorithms, which have been developed to guide CTO operators, allow for a better transfer of knowledge and skills to increase uptake and acceptance of CTO PCI as a whole. PMID:24694104

  18. Survival of lichens and bacteria exposed to outer space conditions - Results of the Lithopanspermia experiments

    NASA Astrophysics Data System (ADS)

    de la Torre, Rosa; Sancho, Leopoldo G.; Horneck, Gerda; Ríos, Asunción de los; Wierzchos, Jacek; Olsson-Francis, Karen; Cockell, Charles S.; Rettberg, Petra; Berger, Thomas; de Vera, Jean-Pierre P.; Ott, Sieglinde; Frías, Jesus Martinez; Melendi, Pablo Gonzalez; Lucas, Maria Mercedes; Reina, Manuel; Pintado, Ana; Demets, René

    2010-08-01

    In the space experiments Lithopanspermia, experimental support was provided to the likelihood of the lithopanspermia concept that considers a viable transport of microorganisms between the terrestrial planets by means of meteorites. The rock colonising lichens Rhizocarpon geographicum and Xanthoria elegans, the vagrant lichen Aspicilia fruticulosa, and endolithic and endoevaporitic communities of cyanobacteria and bacteria with their natural rock substrate were exposed to space for 10 days onboard the Biopan facility of the European Space Agency (ESA). Biopan was closed during launch and re-entry. In addition, in the Stone facility, one sample of R. geographicum on its natural granitic substrate was attached at the outer surface of the re-entry capsule close to the stagnation point, only protected by a thin cover of glass textolite. Post-flight analysis, which included determination of the photosynthetic activity, LIVE/DEAD staining, and germination capacity of the ascospores, demonstrated that all three lichen were quite resistant to outer space conditions, which include the full spectrum of solar extraterrestrial electromagnetic radiation or selected wavelength ranges. This high resistance of the lichens to space appears to be due to their symbiotic nature and protection by their upper pigmented layer, the cortex. In contrast, the rock- or halite-inhabiting bacteria were severely damaged by the same exposure. After atmospheric re-entry, the granite of the Stone sample was transformed into a glassy, nearly homogenous material, with several friction striae. None of the lichen cells survived this re-entry process. The data suggest that lichens are suitable candidates for testing the concept of lithopanspermia, because they are extremely resistant to the harsh environment of outer space. The more critical event is the atmospheric re-entry after being captured by a planet. Experiments simulating the re-entry process of a microbe-carrying meteoroid did not show any

  19. KSC-2012-1066

    NASA Image and Video Library

    2012-01-18

    CAPE CANAVERAL, Fla. -- The stylized shape of the new home for Atlantis at the Kennedy Space Center Visitor Complex incorporates hues of orange and gold to represent both the heat and the bright colors of re-entry. Special gray-colored tiling has been incorporated into the building's design to represent the space shuttle tiles that protected the orbiter from the heat of re-entry. A groundbreaking ceremony for the future home of Atlantis was held Jan. 18. For more information on this and other exhibits at the visitor complex, go to http://www.kennedyspacecenter.com. Artist rendering courtesy of PGAV Destinations for Delaware North Parks & Resorts

  20. Thermal Vacuum Facility for Testing Thermal Protection Systems

    NASA Technical Reports Server (NTRS)

    Daryabeigi, Kamran; Knutson, Jeffrey R.; Sikora, Joseph G.

    2002-01-01

    A thermal vacuum facility for testing launch vehicle thermal protection systems by subjecting them to transient thermal conditions simulating re-entry aerodynamic heating is described. Re-entry heating is simulated by controlling the test specimen surface temperature and the environmental pressure in the chamber. Design requirements for simulating re-entry conditions are briefly described. A description of the thermal vacuum facility, the quartz lamp array and the control system is provided. The facility was evaluated by subjecting an 18 by 36 in. Inconel honeycomb panel to a typical re-entry pressure and surface temperature profile. For most of the test duration, the average difference between the measured and desired pressures was 1.6% of reading with a standard deviation of +/- 7.4%, while the average difference between measured and desired temperatures was 7.6% of reading with a standard deviation of +/- 6.5%. The temperature non-uniformity across the panel was 12% during the initial heating phase (t less than 500 sec.), and less than 2% during the remainder of the test.

  1. ADEPT Sounding Rocket One (SR-1)Flight Experiment Overview

    NASA Technical Reports Server (NTRS)

    Wercinski, Paul; Smith, B.; Yount, B.; Cassell, A.; Kruger, C.; Brivkalns, C.; Makino, A.; Duttta, S.; Ghassemieh, S.; Wu, S.; hide

    2017-01-01

    The SR-1 flight experiment will demonstrate most of the primary end-to-end mission stages including: launch in a stowed configuration, separation and deployment in exo-atmospheric conditions, and passive ballistic re-entry of a 70-degree half-angle faceted cone geometry.

  2. Temporal Organization of the Brain: Neurocognitive Mechanisms and Clinical Implications

    ERIC Educational Resources Information Center

    Dawson, Kim A.

    2004-01-01

    The synchrony between the individual brain and its environment is maintained by a system of internal clocks that together reflect the temporal organization of the organism. Extending the theoretical work of Edelman and others, the temporal organization of the brain is posited as functioning through "'re-entry" and "'temporal tagging"' and binds…

  3. Descriptions of Community by People with Spinal Cord Injuries: Concepts to Inform Community Integration and Community Rehabilitation

    ERIC Educational Resources Information Center

    Kuipers, Pim; Kendall, Melissa B.; Amsters, Delena; Pershouse, Kiley; Schuurs, Sarita

    2011-01-01

    Effective measurement and optimization of re-entry into the community after injury depends on a degree of understanding of how those injured persons actually perceive their community. In light of the limited research about foundational concepts regarding community integration after spinal cord injury, this study investigated how a large number of…

  4. Astronauts McNair and Stewart prepare for reentry

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronauts Ronald E. McNair and Robert L. Stewart prepare for the re-entry phase of the shuttle Challenger near the end of the 41-B mission. The are stationed behind the crew commander and pilot. Stewart is already wearing his helmet. McNair is stowing some of his gear.

  5. The IXV experience, from the mission conception to the flight results

    NASA Astrophysics Data System (ADS)

    Tumino, G.; Mancuso, S.; Gallego, J.-M.; Dussy, S.; Preaud, J.-P.; Di Vita, G.; Brunner, P.

    2016-07-01

    The atmospheric re-entry domain is a cornerstone of a wide range of space applications, ranging from reusable launcher stages developments, robotic planetary exploration, human space flight, to innovative applications such as reusable research platforms for in orbit validation of multiple space applications technologies. The Intermediate experimental Vehicle (IXV) is an advanced demonstrator which has performed in-flight experimentation of atmospheric re-entry enabling systems and technologies aspects, with significant advancements on Europe's previous flight experiences, consolidating Europe's autonomous position in the strategic field of atmospheric re-entry. The IXV mission objectives were the design, development, manufacturing, assembling and on-ground to in-flight verification of an autonomous European lifting and aerodynamically controlled reentry system, integrating critical re-entry technologies at system level. Among such critical technologies of interest, special attention was paid to aerodynamic and aerothermodynamics experimentation, including advanced instrumentation for aerothermodynamics phenomena investigations, thermal protections and hot-structures, guidance, navigation and flight control through combined jets and aerodynamic surfaces (i.e. flaps), in particular focusing on the technologies integration at system level for flight, successfully performed on February 11th, 2015.

  6. SCIROCCO PWT Test and CFD Rebuilding for RASTAS SPEAR Project

    NASA Astrophysics Data System (ADS)

    Trifoni, E.; Cinquegrana, D.; Purpura, C.

    2014-06-01

    A test was performed at SCIROCCO Plasma Wind Tunnel in the frame of RASTAS SPEAR project to assess the behavior under representative super-orbital re-entry conditions of adhesives for joining and bonding ASTERM, the carbon-phenolic ablative material.

  7. 77 FR 60476 - Sunshine Act Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-03

    ... DISABILITY Sunshine Act Meetings TIME AND DATES: The Members of the National Council on Disability (NCD) will... services, and veterans issues, including re-entry of veterans with disabilities into civilian life. The... for people with disabilities, along with recommendations for policy changes. NCD is charged by...

  8. Successfully Serving the College Bound

    ERIC Educational Resources Information Center

    Hands, Africa S.

    2015-01-01

    Whether they are students taking the traditional path of entering college from high school, or adult first-time or re-entry students, navigating the admissions and financial aid process can be overwhelming for the college bound. Public libraries can help provide information and guidance for a successful start, and this book shows how to do it.…

  9. Impact fuze testing at 3000 m/sec employing explosively accelerating plates

    SciTech Connect

    Gill, W.

    1981-01-01

    The Explosives Testing Division at Sandia has developed a method of simulating a re-entry vehicle impacting the ground. The purpose of the simulation is to evaluate different fusing concepts. The design and operation of this impact testing facility are described.

  10. Steam disinfestation as a methyl bromide alternative in California cut flower nurseries

    USDA-ARS?s Scientific Manuscript database

    Steam may be an effective alternative to methyl bromide in cut flower production in California. Advantages of steam include broad spectrum pest control and a zero hour re-entry interval. The principle disadvantage of sheet steaming is cost effectiveness due to current energy prices and application...

  11. Effect of adult screwworm male size on mating competence

    USDA-ARS?s Scientific Manuscript database

    Screwworms, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), were devastating pests in parts of North America and Central America before their eradication by means of the sterile insect technique (SIT). Now, a barrier is maintained to prevent re-entry of screwworms from endemic regions t...

  12. Water-Repellency Probe

    NASA Technical Reports Server (NTRS)

    Rosen, Charles D.; Mitchell, Shirley M.; Jolly, Stanley R.; Jackson, Richard G.; Fleming, Scott T.; Roberts, William J.; Bell, Daniel R., III

    1996-01-01

    Instrument yielding presence or absence of waterproofing agent at any given depth in blanket developed. In original application, blankets in question part of space shuttle thermal protection system. Instrument utilized to determine extent of waterproofing "burnout" due to re-entry heating and adverse environment exposure.

  13. Mercury Project

    NASA Image and Video Library

    1959-09-01

    An Atlas launch vehicle carrying the Big Joe capsule leaves its launching pad on a 2,000-mile ballistic flight to the altitude of 100 miles. The Big Joe capsule is a boilerplate model of the marned orbital capsule under NASA's Project Mercury. The capsule was recovered and studied for the effect of re-entry heat and other flight stresses.

  14. Toward a Taxonomy of Adult Two-Year College Student Needs.

    ERIC Educational Resources Information Center

    Mangano, Joseph A.; Corrado, Thomas J.

    A survey was conducted at six representative New York State two-year colleges to: (1) determine the relative importance of selected educational needs for students and staff in the business, health services, and trade/technology curricula; and (2) taxonomize the needs of re-entry adult students. Survey respondents included 561 traditional students…

  15. Proceedings of the Annual Midwest Research-to-Practice Conference in Adult and Continuing Education (2nd, DeKalb, Illinois, November 4-5, 1983).

    ERIC Educational Resources Information Center

    Northern Illinois Univ., De Kalb. Coll. of Continuing Education.

    These proceedings consist of 26 presentations. They include, in alphabetical order by author, "Time and Distance: Crucial Factors in Selection of Training and Vocation by Re-entry Women" (Cynthia Bagley), "Using Learner Surveys to Enhance Continuing Education Programs" (Carol Brown), "Designing Inservice Training as a Learning System: The Case of…

  16. Pegasus5 is Co-Winner of NASA's 2016 Software of the Year Award

    NASA Image and Video Library

    2016-11-04

    Shareable video highlighting the Pegasus5 software, which was the co-winner of the NASA's 2016 Software of the Year award. Developed at NASA Ames, it helps in the simulation of air flow around space vehicles during launch and re-entry.

  17. 9 CFR 93.519 - Special provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... signature of the Canadian Port Veterinarian that inspected the swine for entry into Canada shall be recorded... the certificate that accompanies the swine. In all cases it shall be determined by the veterinary... offered for re-entry upon examination by the veterinary inspector at the U.S. port of entry, are found...

  18. 9 CFR 93.215 - Special provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... be recorded on the United States health certificate, or a paper containing the information shall be... veterinary inspector at the United States port of entry that the poultry are the identical poultry covered by..., That all poultry offered for re-entry upon examination by the veterinary inspector at the U.S. port...

  19. Diagram of Liquid Rocket Systems General Arrangement

    NASA Image and Video Library

    1964-05-21

    S64-05966 (1964) --- Diagram shows the general arrangement of the liquid rocket systems on the Gemini spacecraft are shown. The locations of the 25-pound, 85-pound and 100-pound thrusters of the orbital attitude and maneuver system and the 25-pound thrusters of the re-entry control system are shown.

  20. Science Education in Early Childhood (March 9-April 18, 1997). Report on Course.

    ERIC Educational Resources Information Center

    Golda Meir Mount Carmel International Training Centre, Haifa (Israel).

    This document is a report on a 6-week course on science education in early childhood programs. Attending the conference in Israel were 30 participants representing 21 countries from Africa, Asia, Europe, and the Caribbean. Teaching methods included lectures, workshops, small group activities, professional study visits, and a re-entry workshop to…

  1. Effective Stack Design in Air Pollution Control.

    ERIC Educational Resources Information Center

    Clarke, John H.

    1968-01-01

    Stack design problems fall into two general caterories--(1) those of building re-entry, and (2) those of general area pollution. Extensive research has developed adequate information, available in the literature, to permit effective stack design. A major roadblock to effective design has been the strong belief by architects and engineers that high…

  2. Traumatic Brain Injury and Its Effect on Students

    ERIC Educational Resources Information Center

    Rosenthal, Stacy B.

    2012-01-01

    Over one million people suffer a traumatic brain injury every year, many of whom are students between the ages of 5 and 18. Using a qualitative case study approach, I wanted to discover the specific factors that both impede and help the school re-entry process for students in grades kindergarten through twelve so that these students can return to…

  3. TUTCHE - A Program Package for Tutoring Chemical Engineers.

    ERIC Educational Resources Information Center

    Stainthorp, F. P.; And Others

    1983-01-01

    Hardware, software, and operation of a computer package for tutoring chemical engineers is discussed. TUTCHE controls/records use of various student programs, organizing data/results in files on exit so they may be reliably retrieved on re-entry. TUTOR is a separate program allowing a tutor to examine/modify student records held in TUTCHE.…

  4. 75 FR 26683 - Hospital and Outpatient Care for Veterans Released From Incarceration to Transitional Housing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-12

    ..., Medical devices, Medical research, Mental health programs, Nursing homes, Philippines, Reporting and... mental health issues are not addressed during the transitional period, upon release, many of these.... Mallik-Kane, K, and Visher, C.A., Health and prisoner re-entry: How physical, mental, and substance abuse...

  5. 76 FR 11338 - Hospital and Outpatient Care for Veterans Released From Incarceration to Transitional Housing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-02

    ... devices, Medical research, Mental health programs, Nursing homes, Philippines, Reporting and recordkeeping... recidivism. Mallik-Kane, K, and Visher, C.A., Health and prisoner re-entry: How physical, mental, and... mental health conditions is a low-cost powerful tool in preventing recidivism. We received three comments...

  6. Traumatic Brain Injury and Its Effect on Students

    ERIC Educational Resources Information Center

    Rosenthal, Stacy B.

    2012-01-01

    Over one million people suffer a traumatic brain injury every year, many of whom are students between the ages of 5 and 18. Using a qualitative case study approach, I wanted to discover the specific factors that both impede and help the school re-entry process for students in grades kindergarten through twelve so that these students can return to…

  7. Effective Stack Design in Air Pollution Control.

    ERIC Educational Resources Information Center

    Clarke, John H.

    1968-01-01

    Stack design problems fall into two general caterories--(1) those of building re-entry, and (2) those of general area pollution. Extensive research has developed adequate information, available in the literature, to permit effective stack design. A major roadblock to effective design has been the strong belief by architects and engineers that high…

  8. Water-Repellency Probe

    NASA Technical Reports Server (NTRS)

    Rosen, Charles D.; Mitchell, Shirley M.; Jolly, Stanley R.; Jackson, Richard G.; Fleming, Scott T.; Roberts, William J.; Bell, Daniel R., III

    1996-01-01

    Instrument yielding presence or absence of waterproofing agent at any given depth in blanket developed. In original application, blankets in question part of space shuttle thermal protection system. Instrument utilized to determine extent of waterproofing "burnout" due to re-entry heating and adverse environment exposure.

  9. Identifying Life Challenges of Women at a Branch Campus through Life Course Interviews: Implications for Service Delivery

    ERIC Educational Resources Information Center

    Horn-Johnson, Tancy Clarissa

    2016-01-01

    An increasing number of women are returning to school as nontraditional students to complete their bachelor's degrees. These women may have specific needs related to life transitions and re-entry into postsecondary education that traditional students do not. The purpose of this study was to gain insight into the experiences of women who are…

  10. Women Emerge in the Seventies. University Women: A Series of Essays, Volume III.

    ERIC Educational Resources Information Center

    Swoboda, Marian J., Ed.; Roberts, Audrey J., Ed.

    This monograph reviews the role of women in the development of public higher education at the University of Wisconsin with special focus on the period of the 1970s. Essays are presented in the categories of the politicization of women, curriculum, language, athletics, lifestyle, and the re-entry woman. Essays include: "The Women's Movement…

  11. A Slow Look at Speeded Reading Comprehension Tests.

    ERIC Educational Resources Information Center

    Kerstiens, Gene

    1990-01-01

    The definitions of and literature on test speededness are reviewed, and factors and areas in which the tests reveal their strengths and limitations are discussed. The focus of this article is on speeded reading comprehension tests used for entry or re-entry placement in postsecondary institutions. Speeded tests were prompted by the accelerating…

  12. BLDG. 29 - INTERIOR (CLOSEUP) - GONDOLA - MSC

    NASA Image and Video Library

    1966-01-01

    The new centrifuge at MSC, located in the Flight Acceleration Facility (FAF), Bldg. 29. The 50-ft. arm can swing the 3-man gondola to create G-Forces Astronauts will experience during liftoffs and re-entry conditions. MSC, HOUSTON, TX CN

  13. 76 FR 12076 - Privacy Act of 1974; System of Records

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-04

    ...) and computer screens automatically lock after a preset period of inactivity with re-entry controlled... of the Secretary Privacy Act of 1974; System of Records AGENCY: Defense Logistics Agency, DoD. ACTION: Notice to amend a system of records. SUMMARY: The Defense Logistics Agency is proposing to amend a system...

  14. The Potential of Computational Fluid Dynamics Simulation on Serial Monitoring of Hemodynamic Change in Type B Aortic Dissection.

    PubMed

    Yu, Simon C H; Liu, Wen; Wong, Randolph H L; Underwood, Malcolm; Wang, Defeng

    2016-08-01

    We aimed to assess the potential of computational fluid dynamics simulation (CFD) in detecting changes in pressure and flow velocity in response to morphological changes in type B aortic dissection. Pressure and velocity in four morphological models of type B aortic dissection before and after closure of the entry tear were calculated with CFD and analyzed for changes among the different scenarios. The control model (Model 1) was patient specific and built from the DICOM data of CTA, which bore one entry tear and three re-entry tears. Models 2-4 were modifications of Model 1, with two re-entry tears less in Model 2, one re-entry tear more in Model 3, and a larger entry tear in Model 4. The pressure and velocity pertaining to each of the morphological models were unique. Changes in pressure and velocity findings were accountable by the changes in morphological features of the different models. There was no blood flow in the false lumen across the entry tear after its closure, the blood flow direction across the re-entry tears was reversed after closure of the entry tear. CFD simulation is probably useful to detect hemodynamic changes in the true and false lumens of type B aortic dissection in response to morphological changes, it may potentially be developed into a non-invasive and patient-specific tool for serial monitoring of hemodynamic changes of type B aortic dissection before and after treatment.

  15. HL-20 Wax Model

    NASA Technical Reports Server (NTRS)

    1993-01-01

    A numerically machined wax pattern of the NASA HL-20 orbital re-entry lifting body was cut from a CAD/CAM file. This nine-inch wax model was later used in a lost wax investment casting process to replicate the pattern in ceramic for wind-tunnel aero-heating studies

  16. Career Development Curriculum for Single Parents/Homemakers.

    ERIC Educational Resources Information Center

    Malott, Karen; Taylor, Angela

    This core curriculum, in use at the Homemaker ReEntry Center at Northern Kentucky University, provides three units of materials that teachers can use to help homemakers make the transition to the world of work. The first unit, on personal development, covers such topics such as self-esteem, self-awareness, goal setting, decision making, sex role…

  17. Why School English Needs a "Good Enough" Grammatics (and Not More Grammar)

    ERIC Educational Resources Information Center

    Macken-Horarik, Mary

    2012-01-01

    At the dawn of a national curriculum for English in Australia, grammar has appeared without any serious interrogation of the terms of its re-entry and against ambiguous evidence about its value for teaching writing. What kinds of knowledge about language do teachers need in rhetorically productive teaching? This article investigates the potential…

  18. Identifying Life Challenges of Women at a Branch Campus through Life Course Interviews: Implications for Service Delivery

    ERIC Educational Resources Information Center

    Horn-Johnson, Tancy Clarissa

    2016-01-01

    An increasing number of women are returning to school as nontraditional students to complete their bachelor's degrees. These women may have specific needs related to life transitions and re-entry into postsecondary education that traditional students do not. The purpose of this study was to gain insight into the experiences of women who are…

  19. Astronauts McNair and Stewart prepare for reentry

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronauts Ronald E. McNair and Robert L. Stewart prepare for the re-entry phase of the shuttle Challenger near the end of the 41-B mission. The are stationed behind the crew commander and pilot. Stewart is already wearing his helmet. McNair is stowing some of his gear.

  20. Descriptions of Community by People with Spinal Cord Injuries: Concepts to Inform Community Integration and Community Rehabilitation

    ERIC Educational Resources Information Center

    Kuipers, Pim; Kendall, Melissa B.; Amsters, Delena; Pershouse, Kiley; Schuurs, Sarita

    2011-01-01

    Effective measurement and optimization of re-entry into the community after injury depends on a degree of understanding of how those injured persons actually perceive their community. In light of the limited research about foundational concepts regarding community integration after spinal cord injury, this study investigated how a large number of…

  1. ACUTE STUDIES OF INHALED CHLORINE IN F344 RATS SUGGEST ALTERNATIVE TO HABER'S RULE FOR RISK EXTRAPOLATIONS

    EPA Science Inventory

    Chlorine (CI2), a high-production volume air pollutant, is an irritant of interest to homeland security. Risk assessment approaches to establish egress or re-entry levels typically use an assumption based on Haber's Rule and apply a concentration times duration ("C x t") adjustme...

  2. Harvest impacts in uneven-aged and even-aged Missouri Ozark forests

    Treesearch

    John P. Dwyer; Daniel C. Dey; William D. Walter; Randy G. Jensen

    2004-01-01

    Forest managers are concerned about the potential damage to residual trees and site from cyclic harvest re-entries into the same forest stand. This study summarizes logging and felling damage resulting from the harvesting of silvicultural treatments on a large landscape experiment in southern Missouri that is designed to compare impacts of even-aged, uneven-aged and no...

  3. Of Radicals and DREAMers: Harnessing Exceptionality to Challenge Immigration Control

    ERIC Educational Resources Information Center

    Heredia, Luisa Laura

    2015-01-01

    This article contributes to the literature on undocumented youth activism and citizenship by assessing undocumented youth's challenges to a growing regime of migration control in the US. It uses Doug McAdam's tactical interaction as an analytical lens to explore two consecutive high-risk campaigns, ICE infiltrations and expulsion/re-entry. In this…

  4. ACUTE STUDIES OF INHALED CHLORINE IN F344 RATS SUGGEST ALTERNATIVE TO HABER'S RULE FOR RISK EXTRAPOLATIONS

    EPA Science Inventory

    Chlorine (CI2), a high-production volume air pollutant, is an irritant of interest to homeland security. Risk assessment approaches to establish egress or re-entry levels typically use an assumption based on Haber's Rule and apply a concentration times duration ("C x t") adjustme...

  5. Temporal Organization of the Brain: Neurocognitive Mechanisms and Clinical Implications

    ERIC Educational Resources Information Center

    Dawson, Kim A.

    2004-01-01

    The synchrony between the individual brain and its environment is maintained by a system of internal clocks that together reflect the temporal organization of the organism. Extending the theoretical work of Edelman and others, the temporal organization of the brain is posited as functioning through "'re-entry" and "'temporal tagging"' and binds…

  6. Proceedings of the Annual Midwest Research-to-Practice Conference in Adult and Continuing Education (2nd, DeKalb, Illinois, November 4-5, 1983).

    ERIC Educational Resources Information Center

    Northern Illinois Univ., De Kalb. Coll. of Continuing Education.

    These proceedings consist of 26 presentations. They include, in alphabetical order by author, "Time and Distance: Crucial Factors in Selection of Training and Vocation by Re-entry Women" (Cynthia Bagley), "Using Learner Surveys to Enhance Continuing Education Programs" (Carol Brown), "Designing Inservice Training as a Learning System: The Case of…

  7. Inter-Agency Coordination: The Key to Successfully Transition Juvenile Offenders Back into the Educational Mainstream

    ERIC Educational Resources Information Center

    Gordon, Robyn Beth

    2013-01-01

    The focus of this study was to determine the characteristics of successful re-entry programs for youth as they transition back into the educational mainstream. The study was also used to determine the implementation needed for effective inter-agency coordination of social service systems for students to successfully transition into the educational…

  8. Of Radicals and DREAMers: Harnessing Exceptionality to Challenge Immigration Control

    ERIC Educational Resources Information Center

    Heredia, Luisa Laura

    2015-01-01

    This article contributes to the literature on undocumented youth activism and citizenship by assessing undocumented youth's challenges to a growing regime of migration control in the US. It uses Doug McAdam's tactical interaction as an analytical lens to explore two consecutive high-risk campaigns, ICE infiltrations and expulsion/re-entry. In this…

  9. Developing Survival Skills Workshops for Urban Women.

    ERIC Educational Resources Information Center

    Thurston, Linda P.; Greenwood, Charles R.

    Survival Skills for Urban Women is a series of 10 3-hour workshops designed for low-income minority women. The workshops cover the following topics: (1) assertiveness; (2) personal health; (3) nutrition; (4) money management; (5) child management; (6) legal rights; (7) self-advocacy; (8) crisis coping; (9) community resources; and (10) re-entry to…

  10. CPAS Parachute Testing, Model Development, & Verification

    NASA Technical Reports Server (NTRS)

    Romero, Leah M.

    2013-01-01

    Capsule Parachute Assembly System (CPAS) is the human rated parachute system for the Orion vehicle used during re-entry. Similar to Apollo parachute design. Human rating requires additional system redundancy. A Government Furnished Equipment (GFE) project responsible for: Design; Development testing; Performance modeling; Fabrication; Qualification; Delivery

  11. Normal and abnormal electrical propagation in the small intestine.

    PubMed

    Lammers, W J E P

    2015-02-01

    As in other muscular organs, small intestinal motility is determined to a large degree by the electrical activities that occur in the smooth muscle layers of the small intestine. In recent decades, the interstitial cells of Cajal, located in the myenteric plexus, have been shown to be responsible for the generation and propagation of the electrical impulse: the slow wave. It was also known that the slow waves as such do not cause contraction, but that the action potentials ('spikes') that are generated by the slow waves are responsible for the contractions. Recording from large number of extracellular electrodes simultaneously is one method to determine origin and pattern of propagation of these electrical signals. This review reports the characteristics of slow wave propagation through the intestinal tube, the occurrence of propagation blocks along its length, which explains the well-known decrease in frequency, and the specific propagation pattern of the spikes that follow the slow waves. But the value of high-resolution mapping is highest in discovering and analysing mechanisms of arrhythmias in the gut. Most recently, circus movements (also called 're-entries') have been described in the small intestine in several species. Moreover, several types of re-entries have now been described, some similar to what may occur in the heart, such as functional re-entries, but others more unique to the small intestine, such as circumferential re-entry. These findings seem to suggest the possibilities of hitherto unknown pathologies that may be present in the small intestine.

  12. Traumatic Brain Injury: What the Teacher Needs To Know.

    ERIC Educational Resources Information Center

    Pieper, Betty

    Intended for use by the classroom teacher, this guide presents teaching suggestions as well as suggested resources for teaching children with traumatic brain injuries (TBI). Emphasis is placed on working with the injured family and the importance of planning for transition and re-entry into the classroom through a continuum of settings. Teachers…

  13. The Space Shuttle Columbia Preservation Project - The Debris Loan Process

    NASA Technical Reports Server (NTRS)

    Thurston, Scott; Comer, Jim; Marder, Arnold; Deacon, Ryan

    2005-01-01

    The purpose of this project is to provide a process for loan of Columbia debris to qualified researchers and technical educators to: (1) Aid in advanced spacecraft design and flight safety development (2) Advance the study of hypersonic re-entry to enhance ground safety. (3) Train and instruct accident investigators and (4) Establish an enduring legacy for Space Shuttle Columbia and her crew.

  14. Impact of Teenage Motherhood on the Academic Performance in Public Primary Schools in Bungoma County, Kenya

    ERIC Educational Resources Information Center

    Barmao-Kiptanui, Catherine; Kindiki, Jonah Nyaga; Lelan, Joseph K.

    2015-01-01

    Teenage pregnancy and motherhood is a concern in both developed and developing countries and is a complex reality of contemporary society however the re-entry of teenage mothers into the school system continues to demand attention as society's negative attitude towards pregnant girls and teenage mothers persists. Those who do return to school…

  15. G. M. Koelemay well No. 1, Jefferson County, Texas. Volume I. Completion and testing: testing geopressured geothermal reservoirs in existing wells. Final report

    SciTech Connect

    Not Available

    1980-01-01

    The acquisition, completion, and testing of a geopressured-geothermal well are described. The following are covered: geology; petrophysics; re-entry and completion operations - test well; drilling and completion operations - disposal well; test objectives; surface testing facilities; pre-test operations; test sequence; test results and analysis; and return of wells and location to operator. (MHR)

  16. Inter-Agency Coordination: The Key to Successfully Transition Juvenile Offenders Back into the Educational Mainstream

    ERIC Educational Resources Information Center

    Gordon, Robyn Beth

    2013-01-01

    The focus of this study was to determine the characteristics of successful re-entry programs for youth as they transition back into the educational mainstream. The study was also used to determine the implementation needed for effective inter-agency coordination of social service systems for students to successfully transition into the educational…

  17. RITD - Adapting Mars Entry, Descent and Landing System for Earth

    NASA Astrophysics Data System (ADS)

    Heilimo, Jyri; Aleksashkin, Sergey; Martynov, Maxim; Schmidt, Walter; Harri, Ari-Matti; Vsevolod Koryanov, D.; Kazakovtcev, Victor; Haukka, Harri; Arruego, Ignacio; Finchenko, Valery; Ostresko, Boris; Ponomarenko, Andrei; Martin, Susanna; Siili, Tero

    Abstract A new generation of inflatable Entry, Descent and Landing System (EDLS) or Mars has been developed. It is used in both the initial atmospheric entry and atmospheric descent before the semi-hard impact of the penetrator into Martian surface. The EDLS applicability to Earth’s atmosphere is studied by the EU/RITD [1] project. Project focuses to the analysis and tests of the transonic behaviour of this compact and light weight payload entry system at the Earth re-entry 1. EDLS for Earth The dynamical stability of the craft is analysed, concentrating on the most critical part of the atmospheric re-entry, the transonic phase. In Martian atmosphere the MetNet vehicle stability during the transonic phase is understood. However, in the more dense Earth’s atmosphere, the transonic phase is shorter and turbulence more violent. Therefore, the EDLS has to be sufficiently dynamically stable to overcome the forces tending to deflect the craft from its nominal trajectory and attitude. The preliminary design of the inflatable EDLS for Earth will be commenced once the scaling of the re-entry system and the dynamical stability analysis have been performed. The RITD-project concentrates on mission and applications achievable with the current MetNet-type (i.e. “Mini-1” category) of lander, and on requirements posed by other type Earth re-entry concepts. 2. Entry Angle Determination for Mini-1 - lander For successful Earth landing, the suitable re-entry angle and velocity with specific descent vehicle (DV) mass and heat flux parameters need to be determined. These key parameters in determining the Earth re-entry for DV are: - qmax (kW/m2): maximal specific heat flux, - Q (MJ/m2): specific integral heat flux to DV front shield, - m (kg): descent vehicle (DV) mass, - V (m/s): re-entry velocity and - theta(deg.): flight-path angle at Earth re-entry For Earth re-entry, the calculation results in the optimal value of entry velocity for MetNet (“Mini-1” category) -type

  18. RITD - Adapting Mars Entry, Descent and Landing System for Earth

    NASA Astrophysics Data System (ADS)

    Heilimo, Jyri; Harri, Ari-Matti; Aleksashkin, Sergey; Koryanov, Vsevolod; Arruego, Ignacio; Schmidt, Walter; Haukka, Harri; Finchenko, Valery; Martynov, Maxim; Ostresko, Boris; Ponomarenko, Andrey; Kazakovtsev, Viktor; Martin, Susanna; Siili, Tero

    2014-05-01

    A new generation of inflatable Entry, Descent and Landing System (EDLS) for Mars has been developed. It is used in both the initial atmospheric entry and atmospheric descent before the semi-hard impact of the penetrator into Martian surface. The EDLS applicability to Earth's atmosphere is studied by the EU/RITD [1] project. Project focuses to the analysis and tests of the transonic behaviour of this compact and light weight payload entry system at the Earth re-entry. 1. EDLS for Earth The dynamical stability of the craft is analysed, concentrating on the most critical part of the atmospheric re-entry, the transonic phase. In Martian atmosphere the MetNet vehicle stability during the transonic phase is understood. However, in the more dense Earth's atmosphere, the transonic phase is shorter and turbulence more violent. Therefore, the EDLS has to be sufficiently dynamically stable to overcome the forces tending to deflect the craft from its nominal trajectory and attitude. The preliminary design of the inflatable EDLS for Earth will be commenced once the scaling of the re-entry system and the dynamical stability analysis have been performed. The RITD-project concentrates on mission and applications achievable with the current MetNet-type (i.e. 'Mini-1' category) of lander, and on requirements posed by other type Earth re-entry concepts. 2. Entry Angle Determination for Mini-1 - lander For successful Earth landing, the suitable re-entry angle and velocity with specific descent vehicle (DV) mass and heat flux parameters need to be determined. These key parameters in determining the Earth re-entry for DV are: qmax (kW/m2): maximal specific heat flux, Q (MJ/m2): specific integral heat flux to DV front shield, m (kg): descent vehicle (DV) mass, V (m/s): re-entry velocity and Θ (deg.): flight-path angle at Earth re-entry For Earth re-entry, the calculation results in the optimal value of entry velocity for MetNet ('Mini-1' category) -type lander, with mass of 22kg, being

  19. Effect of regional differences in cardiac cellular electrophysiology on the stability of ventricular arrhythmias: a computational study

    NASA Astrophysics Data System (ADS)

    Clayton, Richard H.; Holden, Arun V.

    2003-01-01

    Re-entry is an important mechanism of cardiac arrhythmias. During re-entry a wave of electrical activation repeatedly propagates into recovered tissue, rotating around a rod-like filament. Breakdown of a single re-entrant wave into multiple waves is believed to underlie the transition from ventricular tachycardia to ventricular fibrillation. Several mechanisms of breakup have been identified including the effect of anisotropic conduction in the ventricular wall. Cells in the inner and outer layers of the ventricular wall have different action potential durations (APD), and support re-entrant waves with different periods. The aim of this study was to use a computational approach to study twisting and breakdown in a transmural re-entrant wave spanning these regions, and examine the relative role of this effect and anisotropic conduction. We used a simplified model of action potential conduction in the ventricular wall that we modified so that it supported stable re-entry in an anisotropic model with uniform APD. We first examined the effect of regional differences on breakdown in an isotropic model with transmural differences in APD, and found that twisting of the re-entrant filament resulted in buckling and breakdown during the second cycle of re-entry. We found that breakdown was amplified in the anisotropic model, resulting in complex activation in the region of longest APD. This study shows that regional differences in cardiac electrophysiology are a potentially important mechanism for destabilizing re-entry and may act synergistically with other mechanisms to mediate the transition from ventricular tachycardia to ventricular fibrillation.

  20. One-year outcomes after successful chronic total occlusion percutaneous coronary intervention.

    PubMed

    Wilson, W M; Walsh, S J; Bagnall, A; Yan, A T; Hanratty, C G; Egred, M; Smith, E; Oldroyd, K G; McEntegart, M; Irving, J; Douglas, H; Strange, J; Spratt, J C

    2017-03-15

    We aimed to determine clinical outcomes 1 year after successful chronic total occlusion (CTO) PCI and, in particular, whether use of dissection and re-entry strategies affects clinical outcomes. Hybrid approaches have increased the procedural success of CTO percutaneous coronary intervention (PCI) but longer-term outcomes are unknown, particularly in relation to dissection and re-entry techniques. Data were collected for consecutive CTO PCIs performed by hybrid-trained operators from 7 United Kingdom (UK) centres between 2012 and 2014. The primary endpoint (death, myocardial infarction, unplanned target vessel revascularization) was measured at 12 months along with angina status. One-year follow up data were available for 96% of successful cases (n = 805). In total, 85% of patients had a CCS angina class of 2-4 prior to CTO PCI. Final successful procedural strategy was antegrade wire escalation 48%; antegrade dissection and re-entry (ADR) 21%; retrograde wire escalation 5%; retrograde dissection and re-entry (RDR) 26%. Overall, 47% of CTOs were recanalized using dissection and re-entry strategies. During a mean follow up of 11.5 ± 3.8 months, the primary endpoint occurred in 8.6% (n = 69) of patients (10.3% (n = 39/375) in DART group and 7.0% (n = 30/430) in wire-based cases). The majority of patients (88%) had no or minimal angina (CCS class 0 or 1). ADR and RDR were used more frequently in more complex cases with greater disease burden, however, the only independent predictor of the primary endpoint was lesion length. CTO PCI in complex lesions using the hybrid approach is safe, effective and has a low one-year adverse event rate. The method used to recanalize arteries was not associated with adverse outcomes. © 2017 Wiley Periodicals, Inc.

  1. Parametric Study of Cantilever Plates Exposed to Supersonic and Hypersonic Flows

    NASA Astrophysics Data System (ADS)

    Sri Harsha, A.; Rizwan, M.; Kuldeep, S.; Giridhara Prasad, A.; Akhil, J.; Nagaraja, S. R.

    2017-08-01

    Analysis of hypersonic flows associated with re-entry vehicles has gained a lot of significance due to the advancements in Aerospace Engineering. An area that is studied extensively by researchers is the simultaneous reduction aerodynamic drag and aero heating in re-entry vehicles. Out of the many strategies being studied, the use of aerospikes at the stagnation point of the vehicle is found to give favourable results. The structural stability of the aerospike becomes important as it is exposed to very high pressures and temperatures. Keeping this in view, the deflection and vibration of an inclined cantilever plate in hypersonic flow is carried out using ANSYS. Steady state pressure distribution obtained from Fluent is applied as load to the transient structural module for analysis. After due validation of the methods, the effects of parameters like flow Mach number, plate inclination and plate thickness on the deflection and vibration are studied.

  2. A Modified Triples Algorithm for Flush Air Data Systems that Allows a Variety of Pressure Port Configurations

    NASA Technical Reports Server (NTRS)

    Millman, Daniel R.

    2017-01-01

    Air Data Systems (FADS) are becoming more prevalent on re-entry vehicles, as evi- denced by the Mars Science Laboratory and the Orion Multipurpose Crew Vehicle. A FADS consists of flush-mounted pressure transducers located at various locations on the fore-body of a flight vehicle or the heat shield of a re-entry capsule. A pressure model converts the pressure readings into useful air data quantities. Two algorithms for converting pressure readings to air data have become predominant- the iterative Least Squares State Estimator (LSSE) and the Triples Algorithm. What follows herein is a new algorithm that takes advantage of the best features of both the Triples Algorithm and the LSSE. This approach employs the potential flow model and strategic differencing of the Triples Algorithm to obtain the defective flight angles; however, the requirements on port placement are far less restrictive, allowing for configurations that are considered optimal for a FADS.

  3. Post-Flight Analysis of GPSR Performance During Orion Exploration Flight Test 1

    NASA Technical Reports Server (NTRS)

    Barker, Lee; Mamich, Harvey; McGregor, John

    2016-01-01

    On 5 December 2014, the first test flight of the Orion Multi-Purpose Crew Vehicle executed a unique and challenging flight profile including an elevated re-entry velocity and steeper flight path angle to envelope lunar re-entry conditions. A new navigation system including a single frequency (L1) GPS receiver was evaluated for use as part of the redundant navigation system required for human space flight. The single frequency receiver was challenged by a highly dynamic flight environment including flight above low Earth orbit, as well as single frequency operation with ionospheric delay present. This paper presents a brief description of the GPS navigation system, an independent analysis of flight telemetry data, and evaluation of the GPSR performance, including evaluation of the ionospheric model employed to supplement the single frequency receiver. Lessons learned and potential improvements will be discussed.

  4. Remote Controlled Orbiter Capability

    NASA Technical Reports Server (NTRS)

    Garske, Michael; delaTorre, Rafael

    2007-01-01

    The Remote Control Orbiter (RCO) capability allows a Space Shuttle Orbiter to perform an unmanned re-entry and landing. This low-cost capability employs existing and newly added functions to perform key activities typically performed by flight crews and controllers during manned re-entries. During an RCO landing attempt, these functions are triggered by automation resident in the on-board computers or uplinked commands from flight controllers on the ground. In order to properly route certain commands to the appropriate hardware, an In-Flight Maintenance (IFM) cable was developed. Currently, the RCO capability is reserved for the scenario where a safe return of the crew from orbit may not be possible. The flight crew would remain in orbit and await a rescue mission. After the crew is rescued, the RCO capability would be used on the unmanned Orbiter in an attempt to salvage this national asset.

  5. Folding of Polymer Chains in Early Stage of Crystallization

    NASA Astrophysics Data System (ADS)

    Yuan, Shichen; Miyoshi, Toshikazu

    Understanding the structural formation of long polymer chains in the early stage of crystallization is one of the long-standing problems in polymer science. Using solid state NMR, we investigated chain trajectory of isotactic polypropylene in the mesomorphic nano-domains formed via rapid and deep quenching. Comparison of experimental and simulated 13C-13C Double Quantum (DQ) buildup curves demonstrated that instead of random re-entry models and solidification models, individual chains in the mesomorphic form iPP adopt adjacent reentry sequences with an average folding number of = 3-4 (assuming an adjacent re-entry fraction of of 100%) during mesomorphic formation process via nucleation and growth in the early stage. This work was financially supported by the National Science Foundation (Grant DMR-1105829 and 1408855) and startup funds from the UA.

  6. Monitoring of Thermal Protection Systems Using Robust Self-Organizing Optical Fiber Sensing Networks

    NASA Technical Reports Server (NTRS)

    Richards, Lance

    2013-01-01

    The general aim of this work is to develop and demonstrate a prototype structural health monitoring system for thermal protection systems that incorporates piezoelectric acoustic emission (AE) sensors to detect the occurrence and location of damaging impacts, and an optical fiber Bragg grating (FBG) sensor network to evaluate the effect of detected damage on the thermal conductivity of the TPS material. Following detection of an impact, the TPS would be exposed to a heat source, possibly the sun, and the temperature distribution on the inner surface in the vicinity of the impact measured by the FBG network. A similar procedure could also be carried out as a screening test immediately prior to re-entry. The implications of any detected anomalies in the measured temperature distribution will be evaluated for their significance in relation to the performance of the TPS during re-entry. Such a robust TPS health monitoring system would ensure overall crew safety throughout the mission, especially during reentry

  7. RITD - Adapting Mars Entry, Descent and Landing System for Earth

    NASA Astrophysics Data System (ADS)

    Haukka, H.; Heilimo, J.; Harri, A.-M.; Aleksashkin, S.; Koryanov, V.; Arruego, I.; Schmidt, W.; Finchenko, V.; Martynov, M.; Ponomarenko, A.; Kazakovtsev, V.; Martin, S.

    2015-10-01

    We have developed an atmospheric re-entry and descent system concept based on inflatable hypersonic decelerator techniques that were originally developed for Mars. The ultimate goal of this EU-funded RITD-project (Re-entry: Inflatable Technology Development) was to assess the benefits of this technology when deploying small payloads from low Earth orbits to the surface of the Earth with modest costs. The principal goal was to assess and develop a preliminary EDLS design for the entire relevant range of aerodynamic regimes expected to be encountered in Earth's atmosphere during entry, descent and landing. Low Earth Orbit (LEO) and even Lunar applications envisaged include the use of the EDLS approach in returning payloads of 4-8 kg down to the surface.

  8. Health status of people with work-related musculoskeletal disorders in return to work programs: a Malaysian study.

    PubMed

    Murad, Mohd Suleiman; O'Brien, Lisa; Farnworth, Louise; Chien, Chi-Wen

    2013-07-01

    This study examined the health status of injured workers with musculoskeletal disorders enrolled in the Malaysian Return to Work (RTW) program. The 102 participants were categorized into three RTW groups: Off-work (n = 30, 29.4%), Re-entry (n = 44, 43.1%), and Maintenance (n = 28, 27.5%). Overall health status, as measured by the SF-36 version 2, of the workers exhibited below average compared to the internationally established normative population, with their physical health component summary rated lower than mental health. Across the different groups, significant differences were found in role-physical, vitality, bodily pain, general health, and mental health. However, the mean values of these variables were higher in the Maintenance group and were found significant. The current health status of injured workers at Off-work and Re-entry phases was significantly low and warranted to be improved by involving other health professionals such as occupational therapists, ergonomists, and psychologists.

  9. Flutter Analysis of the Shuttle Tile Overlay Repair Concept

    NASA Technical Reports Server (NTRS)

    Bey, Kim S.; Scott, Robert C.; Bartels, Robert E.; Waters, William A.; Chen, Roger

    2007-01-01

    The Space Shuttle tile overlay repair concept, developed at the NASA Johnson Space Center, is designed for on-orbit installation over an area of damaged tile to permit safe re-entry. The thin flexible plate is placed over the damaged area and secured to tile at discreet points around its perimeter. A series of flutter analyses were performed to determine if the onset of flutter met the required safety margins. Normal vibration modes of the panel, obtained from a simplified structural analysis of the installed concept, were combined with a series of aerodynamic analyses of increasing levels of fidelity in terms of modeling the flow physics to determine the onset of flutter. Results from these analyses indicate that it is unlikely that the overlay installed at body point 1800 will flutter during re-entry.

  10. Expert- Demonstrating Reentry Aerothermodinamics Phenomena From A System Perspective

    NASA Astrophysics Data System (ADS)

    Massobrio, F.; Passarelli, G.; Gavira-Izquierdo, J.; Ratti, F.

    2011-05-01

    EXPERT is developed by the European Space Agency (ESA) in order to provide the scientific community with quality data on critical aero-thermodynamic phenomena encountered during hypersonic flights as well as to provide industry with system experience of re-entry vehicle manufacturing and development of hypersonic instrumentation. EXPERT is equipped with 14 experiments provided by several scientific institutions all around Europe. The experiments address major aerothermodinamics phenomena: TPS material characterization, surface catalysis and oxidation, plasma spectroscopy, laminar to turbulent transition, flow separation and reattachment, shock-boundary layer interactions, base flow characteristic and aerodynamic characterization of flap control surfaces. The paper focus on the status of the EXPERT project: the design activities and the on going manufacturing, the main challenges and the expected flight data results. EXPERT will benefit future atmospheric re- entry activities ranging from cargo to human orbital transportation systems as well as re-usable launchers and scientific probes.

  11. Evidence for an interplay between cell cycle progression and the initiation of differentiation between life cycle forms of African trypanosomes

    PubMed Central

    1994-01-01

    Successful transmission of the African trypanosome between the mammalian host blood-stream and the tsetse fly vector involves dramatic alterations in the parasite's morphology and biochemistry. This differentiation through to the tsetse midgut procyclic form is accompanied by re-entry into a proliferative cell cycle. Using a synchronous differentiation model and a variety of markers diagnostic for progress through both differentiation and the cell cycle, we have investigated the interplay between these two processes. Our results implicate a relationship between the trypanosome cell cycle position and the perception of the differentiation signal and demonstrate that irreversible commitment to the differentiation occurs rapidly after induction. Furthermore, we show that re-entry into the cell cycle in the differentiating population is synchronous, and that once initiated, progress through the differentiation pathway can be uncoupled from progress through the cell cycle. PMID:8195296

  12. Development and flight qualification of the C-SiC thermal protection systems for the IXV

    NASA Astrophysics Data System (ADS)

    Buffenoir, François; Zeppa, Céline; Pichon, Thierry; Girard, Florent

    2016-07-01

    The Intermediate experimental Vehicle (IXV) atmospheric re-entry demonstrator, developed within the FLPP (Future Launcher Preparatory Programme) and funded by ESA, aimed at developing a demonstration vehicle that gave Europe a unique opportunity to increase its knowledge in the field of advanced atmospheric re-entry technologies. A key technology that has been demonstrated in real conditions through the flight of this ambitious vehicle is the thermal protection system (TPS) of the Vehicle. Within this programme, HERAKLES, Safran Group, has been in charge of the TPS of the windward and nose assemblies of the vehicle, and has developed and manufactured SepcarbInox® ceramic matrix composite (CMC) protection systems that provided a high temperature resistant non ablative outer mould line (OML) for enhanced aerodynamic control. The design and flight justification of these TPS has been achieved through extensive analysis and testing:

  13. Impact analysis of Minuteman III Payload Transporter Type III

    SciTech Connect

    Stirbis, P.P.

    1993-12-01

    An analysis of the impact of the Minuteman III Payload Transporter Type III into a nonyielding target at 46 m.p.h. and 30 m.p.h., and into a yielding target at 46 m.p.h. is presented. The analysis considers the structural response of the tiedown system which secures the Minuteman III re-entry system to the floor of the payload transporter. A finite element model of the re-entry system, its tiedown system, which includes tie-rods and shear pins, and the pallet plate which is attached to the transporter floating plate, was constructed. Because accelerations of the payload transporter are not known, acceleration data from one-quarter scale testing of the Safe Secure Trailer was used to investigate the response of the tiedown system. These accelerations were applied to the pallet plate. The ABAQUS computer code was used to predict the forces in the members of the tiedown system.

  14. New motors solve UBD and HPHT problems

    SciTech Connect

    Stewart, D.; Susman, H.

    1997-08-01

    There are two particular areas where industry contractors have been pushing current downhole motor technology to the limits of its capabilities--high temperature (HPHT) and underbalanced (UBD) operations. Economic incentives for slimhole, short-radius re-entry and multilateral wells have been well established, but until recently, the options for this kind of work have been limited. The increased use of coiled tubing has introduced additional challenges for motor manufacturers, with greater emphasis on shortness for ease of rig-up and steerability. These challenges are addressed by a unique new motor that promises benefits for coiled tubing drilling, re-entry work and multilateral drilling, as well as for geothermal wells.

  15. HYSHOT-2 Aerodynamics

    NASA Astrophysics Data System (ADS)

    Cain, T.; Owen, R.; Walton, C.

    2005-02-01

    The scramjet flight test Hyshot-2, flew on the 30 July 2002. The programme, led by the University of Queensland, had the primary objective of obtaining supersonic combustion data in flight for comparison with measurements made in shock tunnels. QinetiQ was one of the sponsors, and also provided aerodynamic data and trajectory predictions for the ballistic re-entry of the spinning sounding rocket. The unconventional missile geometry created by the nose-mounted asymmetric-scramjet in conjunction with the high angle of attack during re-entry makes the problem interesting. This paper presents the wind tunnel measurements and aerodynamic calculations used as input for the trajectory prediction. Indirect comparison is made with data obtained in the Hyshot-2 flight using a 6 degree-of-freedom trajectory simulation.

  16. Verification and validation of a parallel 3D direct simulation Monte Carlo solver for atmospheric entry applications

    NASA Astrophysics Data System (ADS)

    Nizenkov, Paul; Noeding, Peter; Konopka, Martin; Fasoulas, Stefanos

    2016-07-01

    The in-house direct simulation Monte Carlo solver PICLas, which enables parallel, three-dimensional simulations of rarefied gas flows, is verified and validated. Theoretical aspects of the method and the employed schemes are briefly discussed. Considered cases include simple reservoir simulations and complex re-entry geometries, which were selected from literature and simulated with PICLas. First, the chemistry module is verified using simple numerical and analytical solutions. Second, simulation results of the rarefied gas flow around a 70° blunted-cone, the REX Free-Flyer as well as multiple points of the re-entry trajectory of the Orion capsule are presented in terms of drag and heat flux. A comparison to experimental measurements as well as other numerical results shows an excellent agreement across the different simulation cases. An outlook on future code development and applications is given.

  17. Efficacy of MTA and CEM Cement with Collagen Membranes for Treatment of Class II Furcation Defects

    PubMed Central

    Ghanbari, Habib Ollah; Taheri, Morteza; Abolfazli, Salman; Asgary, Saeed; Gharechahi, Maryam

    2014-01-01

    Objectives: This study aimed to compare the efficacy of MTA and CEM cement in Class II furcation defects in human mandibular molars. Materials and Methods: Forty furcation defects were treated in 16 patients with chronic periodontitis. The clinical parameters of probing depth (PD), vertical and horizontal clinical attachment levels (VCAL and HCAL), open vertical and horizontal furcation depths (OVFD and OHFD), and gingival margin level (GML) were measured at baseline and at 3- and 6-month (re-entry surgery) postoperatively. Data were analyzed at a significance level of P<0.05. Results: Use of MTA and CEM caused significant decreases in PD, VCAL, HCAL, OVFD and OHFD at re-entry, with no statistically significant differences between the two treatment options in soft and hard tissue parameters. Conclusion: Both treatment modalities caused significant gains in attachment levels and bone fills, proving efficacy for treatment of Class II furcation involvements. PMID:25628670

  18. Special people? An exploratory study into re-entering missionaries' identity and resilience.

    PubMed

    Selby, Susan; Braunack-Mayer, Annette; Jones, Alison; Clark, Sheila; Moulding, Nicole; Beilby, Justin

    2011-12-01

    Home country re-entry from cross-cultural missionary work abroad may be associated with psychological distress. Re-entrants experience multiple losses including loss of identity which may be associated with personal/relational identity gaps and depersonalization/dehumanization. However, research suggests that some re-entrants are resilient with good mental health, while others are fragile with poor mental health. The aims of this paper are to explore the nature and frequency of re-entering missionaries' identity gaps and their depersonalization/dehumanization in resilient and fragile re-entrants. Fifteen re-entering adult Australian cross-cultural missionary workers from four interdenominational Australian mission organizations completed semi-structured interviews. Results were analysed using modified Consensual Qualitative Research methods. Links were established between personal/relational identity gaps, depersonalization/dehumanization and resilience on re-entry. Implications for re-entrants' care are discussed with suggestions for further research.

  19. Review and Assessment of ATV Observation Data for Events Characterization

    NASA Astrophysics Data System (ADS)

    Mazoue, Franck; Beck, James; Reynier, Philippe

    2011-02-01

    For investigating ATV re-entry, observation airborne campaigns have been carried out at the end of the mission to ISS of Jules Verne ATV. The observations of re-entry have highlighted that the in-flight scenario was quite different to the nominal one, since two explosions occurred during the flight. In this paper, the data gathered during the observations have been analysed in the perspective of the explosion analysis. The potential explosive elements present on board have been studied and the explosion products identified. To identify the possible scenario that led to the vehicle explosion the list of explosion products has been compared with the radiators put in evidence in the spectra obtained by spectroscopy during the flight. Finally, the most reliable scenario has been identified and the power available for explosion evaluated. This shows that non negligible delta V could have been produced by the explosion.

  20. Cell cycle activation in striatal neurons from Huntington's disease patients and rats treated with 3-nitropropionic acid.

    PubMed

    Pelegrí, Carme; Duran-Vilaregut, Joaquim; del Valle, Jaume; Crespo-Biel, Natàlia; Ferrer, Isidre; Pallàs, Mercè; Camins, Antoni; Vilaplana, Jordi

    2008-11-01

    This study was undertaken to investigate the potential role of cell cycle re-entry in an experimental model of Huntington's disease and in human brain samples. We found that after treatment of rats with the mitochondrial neurotoxin 3-nitropropionic acid, the expression of cell cycle markers of G1 phase measured by immunohistochemistry was induced in the striatal brain region. Furthermore, we detected an increase in the nuclear and also cytoplasmatic E2F-1 expression, suggesting that this protein could activate the apoptotic cascade in rat brain. Western blot analysis of post-mortem brain samples from patients also showed an increase in the expression of E2F-1 and cyclin D1 in comparison with control samples. These results indicate that cell cycle re-entry is activated in Huntington's disease and may contribute to the neurodegenerative process.

  1. Verification and validation of a parallel 3D direct simulation Monte Carlo solver for atmospheric entry applications

    NASA Astrophysics Data System (ADS)

    Nizenkov, Paul; Noeding, Peter; Konopka, Martin; Fasoulas, Stefanos

    2017-03-01

    The in-house direct simulation Monte Carlo solver PICLas, which enables parallel, three-dimensional simulations of rarefied gas flows, is verified and validated. Theoretical aspects of the method and the employed schemes are briefly discussed. Considered cases include simple reservoir simulations and complex re-entry geometries, which were selected from literature and simulated with PICLas. First, the chemistry module is verified using simple numerical and analytical solutions. Second, simulation results of the rarefied gas flow around a 70° blunted-cone, the REX Free-Flyer as well as multiple points of the re-entry trajectory of the Orion capsule are presented in terms of drag and heat flux. A comparison to experimental measurements as well as other numerical results shows an excellent agreement across the different simulation cases. An outlook on future code development and applications is given.

  2. Space Debris Alert System for Aviation

    NASA Astrophysics Data System (ADS)

    Sgobba, Tommaso

    2013-09-01

    Despite increasing efforts to accurately predict space debris re-entry, the exact time and location of re-entry is still very uncertain. Partially, this is due to a skipping effect uncontrolled spacecraft may experience as they enter the atmosphere at a shallow angle. Such effect difficult to model depends on atmospheric variations of density. When the bouncing off ends and atmospheric re-entry starts, the trajectory and the overall location of surviving fragments can be precisely predicted but the time to impact with ground, or to reach the airspace, becomes very short.Different is the case of a functional space system performing controlled re-entry. Suitable forecasts methods are available to clear air and maritime traffic from hazard areas (so-called traffic segregation).In US, following the Space Shuttle Columbia accident in 2003, a re-entry hazard areas location forecast system was putted in place for the specific case of major malfunction of a Reusable Launch Vehicles (RLV) at re-entry. The Shuttle Hazard Area to Aircraft Calculator (SHAAC) is a system based on ground equipment and software analyses and prediction tools, which require trained personnel and close coordination between the organization responsible for RLV operation (NASA for Shuttle) and the Federal Aviation Administration. The system very much relies on the operator's capability to determine that a major malfunction has occurred.This paper presents a US pending patent by the European Space Agency, which consists of a "smart fragment" using a GPS localizer together with pre- computed debris footprint area and direct broadcasting of such hazard areas.The risk for aviation from falling debris is very remote but catastrophic. Suspending flight over vast swath of airspace for every re-entering spacecraft or rocket upper stage, which is a weekly occurrence, would be extremely costly and disruptive.The Re-entry Direct Broadcasting Alert System (R- DBAS) is an original merging and evolution of the Re

  3. Hot-Air Jets/Ceramic Heat Exchangers/ Materials for Nose Cones and Reentry Vehicles

    NASA Image and Video Library

    1957-09-07

    L57-5383 Hot-air jets employing ceramic heat exchangers played an important role at Langley in the study of materials for ballistic missile nose cones and re-entry vehicles. Here a model is being tested in one of theses jets at 4000 degrees Fahrenheit in 1957. Photograph published in Engineer in Charge: A History of the Langley Aeronautical Laboratory, 1917-1958 by James R. Hansen. Page 477.

  4. Probability distribution of von Mises stress in the presence of pre-load.

    SciTech Connect

    Segalman, Daniel Joseph; Field, Richard V.,; Reese, Garth M.

    2013-04-01

    Random vibration under preload is important in multiple endeavors, including those involving launch and re-entry. There are some methods in the literature to begin to address this problem, but there is nothing that accommodates the existence of preloads and the necessity of making probabilistic statements about the stress levels likely to be encountered. An approach to achieve to this goal is presented along with several simple illustrations.

  5. KSC-03pd0332

    NASA Image and Video Library

    2003-02-07

    KENNEDY SPACE CENTER, FLA. -- NASA Administrator Sean O'Keefe (right) visits the Thermal Protection System Facility. At left is Chuck Fontana, associate program manager, Integrated Logistics. O'Keefe is visiting the site to learn more about the TPS products and process in protecting orbiters from the intense heat of launch and re-entry. TPS tiles have been discussed in the investigation into the Columbia tragedy that destroyed the orbiter and claimed the lives of seven astronauts..

  6. KSC-03pd0329

    NASA Image and Video Library

    2003-02-07

    KENNEDY SPACE CENTER, FLA. -- In the Thermal Protection System Facility, NASA Administrator Sean O'Keefe (left) meets workers. O'Keefe is visiting the site to learn more about the TPS products and process in protecting orbiters from the intense heat of launch and re-entry. TPS tiles have been discussed in the investigation into the Columbia tragedy that destroyed the orbiter and claimed the lives of seven astronauts.

  7. KSC-03pd0324

    NASA Image and Video Library

    2003-02-07

    KENNEDY SPACE CENTER, FLA. -- In the Thermal Protection System Facility, NASA Administrator Sean O'Keefe (left) talks to Martin Wilson, project manager. O'Keefe is visiting the site to learn more about the TPS products and process in protecting orbiters from the intense heat of launch and re-entry. TPS tiles have been discussed in the investigation into the Columbia tragedy that destroyed the orbiter and claimed the lives of seven astronauts.

  8. KSC-03pd0325

    NASA Image and Video Library

    2003-02-07

    KENNEDY SPACE CENTER, FLA. -- NASA Administrator Sean O'Keefe (left) speaks to workers in the Thermal Protection System Facility. O'Keefe is visiting the site to learn more about the TPS products and process in protecting orbiters from the intense heat of launch and re-entry. TPS tiles have been discussed in the investigation into the Columbia tragedy that destroyed the orbiter and claimed the lives of seven astronauts.

  9. KSC-03pd0323

    NASA Image and Video Library

    2003-02-07

    KENNEDY SPACE CENTER, FLA. -- NASA Administrator Sean O'Keefe (center) greets Brenda Blackmon, a worker in the Thermal Protection System Facility. O'Keefe is visiting the site to learn more about the TPS products and process in protecting orbiters from the intense heat of launch and re-entry. TPS tiles have been discussed in the investigation into the Columbia tragedy that destroyed the orbiter and claimed the lives of seven astronauts.

  10. KSC-03pd0326

    NASA Image and Video Library

    2003-02-07

    KENNEDY SPACE CENTER, FLA. -- In the Thermal Protection System Facility, NASA Administrator Sean O'Keefe looks at a Dome Heat Shield blanket that is used for Shuttle engines. O'Keefe is visiting the site to learn more about the TPS products and process in protecting orbiters from the intense heat of launch and re-entry. TPS tiles have been discussed in the investigation into the Columbia tragedy that destroyed the orbiter and claimed the lives of seven astronauts.

  11. KSC-03pd0330

    NASA Image and Video Library

    2003-02-07

    KENNEDY SPACE CENTER, FLA. -- NASA Administrator Sean O'Keefe (third from left) talks to workers in the Thermal Protection System Facility. O'Keefe is visiting the site to learn more about the TPS products and process in protecting orbiters from the intense heat of launch and re-entry. TPS tiles have been discussed in the investigation into the Columbia tragedy that destroyed the orbiter and claimed the lives of seven astronauts.

  12. NAVO MSRC Navigator. Spring 2008

    DTIC Science & Technology

    2008-01-01

    CFD), Climate/Weather/Ocean Modeling and Simulation (CWO), Environmental Quality Modeling and Simulation (EQM), Computational Electromagnetic...EINSTEIN and DAVINCI Come to the MSRC The Porthole 19 Visitors to the Naval Oceanographic Office Major Shared Resource Center Navigator Tools and...Events 5SPRING 2008NAVO MSRC NAVIGATOR IntroductIon Higher-altitude missile and re-entry vehicle flowfield simulations often require the

  13. STS-87 Commander Kevin R. Kregel in white room

    NASA Technical Reports Server (NTRS)

    1997-01-01

    STS-87 Commander Kevin Kregel is assisted with his ascent and re- entry flight suit in the white room at Launch Pad 39B by Danny Wyatt, NASA quality assurance specialist. STS-87 is the fourth flight of the United States Microgravity Payload and Spartan-201. A veteran of two space flights (STS-70 and -78), Kregel has logged more than 618 hours in space.

  14. Clinical and radiographic evaluation of Bio-Gen with biocollagen compared with Bio-Gen with connective tissue in the treatment of class II furcation defects: a randomized clinical trial

    PubMed Central

    JENABIAN, Niloofar; HAGHANIFAR, Sina; MABOUDI, Avideh; BIJANI, Ali

    2013-01-01

    Objective Treatment of furcation defects are thought to be challenging. The purpose of this study was to evaluate the clinical and radiographic parameters of Bio-Gen with Biocollagen compared with Bio-Gen with connective tissue in the treatment of Class II furcation defects. Material and Methods In this clinical trial, 24 patients with Class II furcation defect on a buccal or lingual mandibular molar were recruited. After oral hygiene instruction, scaling and root planing and achievement of acceptable plaque control, the patients were randomly chosen to receive either connective tissue and Bio-Gen (case group) or Biocollagen and Bio-Gen (control group). The following parameters were recorded before the first and re-entry surgery (six months later): vertical clinical attachment level (VCAL), gingival index (GI), plaque index (PI), horizontal probing depth (HPD), vertical probing depth (VPD), gingival recession (GR), furcation vertical component (FVC), furcation to alveolar crest (FAC), fornix to base of defect (FBD), and furcation horizontal component (FHC) were calculated at the time of first surgery and during re-entry. A digital periapical radiograph was taken in parallel before first surgery and re-entry. The radiographs were then analyzed by digital subtraction. The differences with p value <0.05 were considered significant. Results Only the mean changes of FAC, FHC, mean of FHC, FBD in re-entry revealed statistically significant differences between the two groups. HPD, VPD, FBD, FAC, and FHC showed statistically significant differences after 6 months in the case group. However, in the control group, statistically significant differences were found in GR and HPD. We did not observe any significant difference in radiographic changes among the two groups. Conclusion The results of this trial indicate that better clinical outcomes can be obtained with connective tissue grafts in combination with bone material compared with a resorbable barrier with bone material

  15. NASA Ames Contributes to Orion / EFT-1 Test Flight (Reporter Pkg)

    NASA Image and Video Library

    2014-12-03

    NASA's Orion spacecraft is built to take humans farther than they've ever gone before. Orion will serve as the exploration vehicle that will carry the crew to space, provide emergency abort capability, sustain the crew during the space travel, and provide safe re-entry from deep space return velocities. NASA's Ames Research Center played a critical role in the development and preparation for the flight test designated Exploration Flight Test 1, or EFT-1.

  16. Analysis of the Reconfigurable Control Capabilities of a Space Access Vehicle (Preprint)

    DTIC Science & Technology

    2006-12-01

    based on dynamic inversion with a non-linear control allocator, is used to linearize the vehicle dynamics over its flight envelope and assign control ...backstepping method. Assessment of the vehicle’s ability to recover from control failures is conducted in this work for a nominal re-entry flight . 15...on dynamic inversion with a non-linear control allocator, is used to linearize the vehicle dynamics over its flight envelope and assign control tasks

  17. Commander Crippen at Forward Flight Deck Commanders Station

    NASA Image and Video Library

    1983-06-24

    STS007-31-1614 & S83-35775 (24 June 1983) --- Astronaut Robert L. Crippen is seen at the commander’s station of the Space Shuttle Challenger as it passes through the Earth’s atmosphere on re-entry. The friction results in a pinkish glow visible through the forward windows on the flight deck. The scene was exposed with a 35mm camera.

  18. Early Rockets

    NASA Image and Video Library

    1958-01-31

    Jupiter-C Missile No. 27 assembly at the Army Ballistic Missile Agency (ABMA), Redstone Arsenal, in Huntsville, Aalabama. The Jupiter-C was a modification of the Redstone Missile, and originally developed as a nose cone re-entry test vehicle for the Jupiter Intermediate Range Ballistic Missile (IRBM). Jupiter-C successfully launched the first American Satellite, Explorer 1, in orbit on January 31, 1958.

  19. Environmental effects of Shuttle launch and landing

    NASA Technical Reports Server (NTRS)

    Potter, A. E.

    1983-01-01

    The areas of concern were the toxic exhaust cloud produced by Shuttle launch, the effect of launch operations on the total ecology, and the sonic boom produced by Orbiter re-entry. Wet acidic dust fell from the exhaust cloud for about ten minutes after launch. The fallout was not entirely unexpected, but the intensity and duration was larger than anticipated. The fallout material is not considered a significant health hazard. Previously announced in STAR as N82-15729

  20. A Micropatterned Human Pluripotent Stem Cell-Based Ventricular Cardiac Anisotropic Sheet for Visualizing Drug-Induced Arrhythmogenicity.

    PubMed

    Shum, Angie M Y; Che, Hui; Wong, Andy On-Tik; Zhang, Chenzi; Wu, Hongkai; Chan, Camie W Y; Costa, Kevin; Khine, Michelle; Kong, Chi-Wing; Li, Ronald A

    2017-01-01

    A novel cardiomimetic biohybrid material, termed as the human ventricular cardiac anisotropic sheet (hvCAS) is reported. Well-characterized human pluripotent stem-cell-derived ventricular cardiomyocytes are strategically aligned to reproduce key electrophysiological features of native human ventricle, which, along with specific selection criteria, allows for a direct visualization of arrhythmic spiral re-entry and represents a revolutionary tool to assess preclinical drug-induced arrhythmogenicity.