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Sample records for address current limitations

  1. Current limiters

    SciTech Connect

    Loescher, D.H.; Noren, K.

    1996-09-01

    The current that flows between the electrical test equipment and the nuclear explosive must be limited to safe levels during electrical tests conducted on nuclear explosives at the DOE Pantex facility. The safest way to limit the current is to use batteries that can provide only acceptably low current into a short circuit; unfortunately this is not always possible. When it is not possible, current limiters, along with other design features, are used to limit the current. Three types of current limiters, the fuse blower, the resistor limiter, and the MOSFET-pass-transistor limiters, are used extensively in Pantex test equipment. Detailed failure mode and effects analyses were conducted on these limiters. Two other types of limiters were also analyzed. It was found that there is no best type of limiter that should be used in all applications. The fuse blower has advantages when many circuits must be monitored, a low insertion voltage drop is important, and size and weight must be kept low. However, this limiter has many failure modes that can lead to the loss of over current protection. The resistor limiter is simple and inexpensive, but is normally usable only on circuits for which the nominal current is less than a few tens of milliamperes. The MOSFET limiter can be used on high current circuits, but it has a number of single point failure modes that can lead to a loss of protective action. Because bad component placement or poor wire routing can defeat any limiter, placement and routing must be designed carefully and documented thoroughly.

  2. Fault current limiter

    DOEpatents

    Darmann, Francis Anthony

    2013-10-08

    A fault current limiter (FCL) includes a series of high permeability posts for collectively define a core for the FCL. A DC coil, for the purposes of saturating a portion of the high permeability posts, surrounds the complete structure outside of an enclosure in the form of a vessel. The vessel contains a dielectric insulation medium. AC coils, for transporting AC current, are wound on insulating formers and electrically interconnected to each other in a manner such that the senses of the magnetic field produced by each AC coil in the corresponding high permeability core are opposing. There are insulation barriers between phases to improve dielectric withstand properties of the dielectric medium.

  3. Integrated Current Limiter

    NASA Astrophysics Data System (ADS)

    Pappalardo, S.; Alfonso, M. M.; Mirabella, I. B.

    2011-10-01

    The LCL has been extensively used in ESA scientific satellites and since a few years ago is being also the baseline device for earth observation satellites such as CRYOSAT 1 and 2, SENTINAL 1, 2 and 3, EARTWATCH, etc. It seems that the use of this LCL is also being considered as an alternative to fuse approach for commercial telecommunication satellites. Scope of this document is to provide a technical description of the Integrated Current Limiter device (shortly ICL later on) developed inside the domain of ESTECContract22049-09-NL-A Twith STMicroelectronics s.r.l. (ref. Invitation to Tender AO/1-5784/08/NL/A T). The design of the ICL device takes into account both ESA and power electronics designer's experience. This experience is more than 25 years long in Europe. The ICL design has been leaded in order to be fully compliant with the applicable specification issued by ESA and the major European power electronics manufacturers that have participated in its edition.

  4. Active inrush-current limiter

    NASA Technical Reports Server (NTRS)

    Kichak, R. A.

    1977-01-01

    By stretching turn-on time from approximately 1 to 200 ms, effects of inrush current (and of associated large current spikes) and current rate of rise (dl/dt) are made potentially less severe. Limiter arrangement consists of time-variable impedance connected in series between input dc power source return and power circuit of converter.

  5. 5 CFR 870.910 - Notification of current addresses.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 2 2012-01-01 2012-01-01 false Notification of current addresses. 870....910 Notification of current addresses. Each assignee must keep the office where the assignment is filed informed of his/her current address....

  6. 5 CFR 870.910 - Notification of current addresses.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 2 2011-01-01 2011-01-01 false Notification of current addresses. 870....910 Notification of current addresses. Each assignee must keep the office where the assignment is filed informed of his/her current address....

  7. 5 CFR 870.910 - Notification of current addresses.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 2 2014-01-01 2014-01-01 false Notification of current addresses. 870....910 Notification of current addresses. Each assignee must keep the office where the assignment is filed informed of his/her current address....

  8. 5 CFR 870.910 - Notification of current addresses.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 2 2013-01-01 2013-01-01 false Notification of current addresses. 870....910 Notification of current addresses. Each assignee must keep the office where the assignment is filed informed of his/her current address....

  9. Passive fault current limiting device

    DOEpatents

    Evans, D.J.; Cha, Y.S.

    1999-04-06

    A passive current limiting device and isolator is particularly adapted for use at high power levels for limiting excessive currents in a circuit in a fault condition such as an electrical short. The current limiting device comprises a magnetic core wound with two magnetically opposed, parallel connected coils of copper, a high temperature superconductor or other electrically conducting material, and a fault element connected in series with one of the coils. Under normal operating conditions, the magnetic flux density produced by the two coils cancel each other. Under a fault condition, the fault element is triggered to cause an imbalance in the magnetic flux density between the two coils which results in an increase in the impedance in the coils. While the fault element may be a separate current limiter, switch, fuse, bimetal strip or the like, it preferably is a superconductor current limiter conducting one-half of the current load compared to the same limiter wired to carry the total current of the circuit. The major voltage during a fault condition is in the coils wound on the common core in a preferred embodiment. 6 figs.

  10. Passive fault current limiting device

    DOEpatents

    Evans, Daniel J.; Cha, Yung S.

    1999-01-01

    A passive current limiting device and isolator is particularly adapted for use at high power levels for limiting excessive currents in a circuit in a fault condition such as an electrical short. The current limiting device comprises a magnetic core wound with two magnetically opposed, parallel connected coils of copper, a high temperature superconductor or other electrically conducting material, and a fault element connected in series with one of the coils. Under normal operating conditions, the magnetic flux density produced by the two coils cancel each other. Under a fault condition, the fault element is triggered to cause an imbalance in the magnetic flux density between the two coils which results in an increase in the impedance in the coils. While the fault element may be a separate current limiter, switch, fuse, bimetal strip or the like, it preferably is a superconductor current limiter conducting one-half of the current load compared to the same limiter wired to carry the total current of the circuit. The major voltage during a fault condition is in the coils wound on the common core in a preferred embodiment.

  11. DC superconducting fault current limiter

    NASA Astrophysics Data System (ADS)

    Tixador, P.; Villard, C.; Cointe, Y.

    2006-03-01

    There is a lack of satisfying solutions for fault currents using conventional technologies, especially in DC networks, where a superconducting fault current limiter could play a very important part. DC networks bring a lot of advantages when compared to traditional AC ones, in particular within the context of the liberalization of the electric market. Under normal operation in a DC network, the losses in the superconducting element are nearly zero and only a small, i.e. a low cost, refrigeration system is then required. The absence of zero crossing of a DC fault current favourably accelerates the normal zone propagation. The very high current slope at the time of the short circuit in a DC grid is another favourable parameter. The material used for the experiments is YBCO deposited on Al2O3 as well as YBCO coated conductors. The DC limitation experiments are compared to AC ones at different frequencies (50-2000 Hz). Careful attention is paid to the quench homogenization, which is one of the key issues for an SC FCL. The University of Geneva has proposed constrictions. We have investigated an operating temperature higher than 77 K. As for YBCO bulk, an operation closer to the critical temperature brings a highly improved homogeneity in the electric field development. The material can then absorb large energies without degradation. We present tests at various temperatures. These promising results are to be confirmed over long lengths.

  12. Limitations of bootstrap current models

    NASA Astrophysics Data System (ADS)

    Belli, E. A.; Candy, J.; Meneghini, O.; Osborne, T. H.

    2014-04-01

    We assess the accuracy and limitations of two analytic models of the tokamak bootstrap current: (1) the well-known Sauter model (1999 Phys. Plasmas 6 2834, 2002 Phys. Plasmas 9 5140) and (2) a recent modification of the Sauter model by Koh et al (2012 Phys. Plasmas 19 072505). For this study, we use simulations from the first-principles kinetic code NEO as the baseline to which the models are compared. Tests are performed using both theoretical parameter scans as well as core-to-edge scans of real DIII-D and NSTX plasma profiles. The effects of extreme aspect ratio, large impurity fraction, energetic particles, and high collisionality are studied. In particular, the error in neglecting cross-species collisional coupling—an approximation inherent to both analytic models—is quantified. Furthermore, the implications of the corrections from kinetic NEO simulations on MHD equilibrium reconstructions is studied via integrated modeling with kinetic EFIT.

  13. 5 CFR 870.910 - Notification of current addresses.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Notification of current addresses. 870.910 Section 870.910 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED) FEDERAL EMPLOYEES' GROUP LIFE INSURANCE PROGRAM Assignments of Life Insurance §...

  14. Adjustable direct current and pulsed circuit fault current limiter

    DOEpatents

    Boenig, Heinrich J.; Schillig, Josef B.

    2003-09-23

    A fault current limiting system for direct current circuits and for pulsed power circuit. In the circuits, a current source biases a diode that is in series with the circuits' transmission line. If fault current in a circuit exceeds current from the current source biasing the diode open, the diode will cease conducting and route the fault current through the current source and an inductor. This limits the rate of rise and the peak value of the fault current.

  15. Transistor current and voltage limiting switch

    NASA Technical Reports Server (NTRS)

    Hilbert, E. E.

    1970-01-01

    Limiting circuit protects the main power supply of electronic modules and limits the current drawn by each module should a short circuit occur. It limits current within one mA when used with direct current of either polarity, or with pulse or ac power sources from direct current to 100 kHz.

  16. High temperature superconducting fault current limiter

    DOEpatents

    Hull, John R.

    1997-01-01

    A fault current limiter (10) for an electrical circuit (14). The fault current limiter (10) includes a high temperature superconductor (12) in the electrical circuit (14). The high temperature superconductor (12) is cooled below its critical temperature to maintain the superconducting electrical properties during operation as the fault current limiter (10).

  17. High temperature superconducting fault current limiter

    DOEpatents

    Hull, J.R.

    1997-02-04

    A fault current limiter for an electrical circuit is disclosed. The fault current limiter includes a high temperature superconductor in the electrical circuit. The high temperature superconductor is cooled below its critical temperature to maintain the superconducting electrical properties during operation as the fault current limiter. 15 figs.

  18. Strategic Science to Address Current and Future Space Weather Needs

    NASA Astrophysics Data System (ADS)

    Mannucci, A. J.; Schwadron, N.; Antiochos, S. K.; Bhattacharjee, A.; Bisi, M. M.; Gopalswamy, N.; Kamalabadi, F.; Pulkkinen, A. A.; Tobiska, W. K.; Weimer, D. R.; Withers, P.

    2014-12-01

    NASA's Living With a Star (LWS) program has contributed a wealth of scientific knowledge that is relevant to space weather and user needs. A targeted approach to science questions has resulted in leveraging new scientific knowledge to improve not only our understanding of the Heliophysics domain, but also to develop predictive capabilities in key areas of LWS science. This fascinating interplay between science and applications promises to benefit both domains. Scientists providing feedback to the LWS program are now discussing an evolution of the targeted approach that explicitly considers how new science improves, or enables, predictive capability directly. Long-term program goals are termed "Strategic Science Areas" (SSAs) that address predictive capabilities in six specific areas: geomagnetically induced currents, satellite drag, solar energetic particles, ionospheric total electron content, radio frequency scintillation induced by the ionosphere, and the radiation environment. SSAs are organized around user needs and the impacts of space weather on society. Scientists involved in the LWS program identify targeted areas of research that reference (or bear upon) societal needs. Such targeted science leads to new discoveries and is one of the valid forms of exploration. In this talk we describe the benefits of targeted science, and how addressing societal impacts in an appropriate way maintains the strong science focus of LWS, while also leading to its broader impacts.

  19. Is Current Hydrogeologic Research Addressing Long-TermPredictions?

    SciTech Connect

    Tsang, Chin-Fu

    2004-09-10

    Hydrogeology is a field closely related to the needs of society. Many problems of current national and local interest require predictions of hydrogeological system behavior, and, in a number of important cases, the period of prediction is tens to hundreds of thousands of years. It is argued that the demand for such long-term hydrogeological predictions casts a new light on the future needs of hydrogeological research. Key scientific issues are no longer concerned only with simple processes or narrowly focused modeling or testing methods, but also with assessment of prediction uncertainties and confidence, couplings among multiple physico-chemical processes occurring simultaneously at a site, and the interplay between site characterization and predictive modeling. These considerations also have significant implications for hydrogeological education. With this view, it is asserted that hydrogeological directions and education need to be reexamined and possibly refocused to address specific needs for long-term predictions.

  20. Self-triggering superconducting fault current limiter

    DOEpatents

    Yuan, Xing; Tekletsadik, Kasegn

    2008-10-21

    A modular and scaleable Matrix Fault Current Limiter (MFCL) that functions as a "variable impedance" device in an electric power network, using components made of superconducting and non-superconducting electrically conductive materials. The matrix fault current limiter comprises a fault current limiter module that includes a superconductor which is electrically coupled in parallel with a trigger coil, wherein the trigger coil is magnetically coupled to the superconductor. The current surge doing a fault within the electrical power network will cause the superconductor to transition to its resistive state and also generate a uniform magnetic field in the trigger coil and simultaneously limit the voltage developed across the superconductor. This results in fast and uniform quenching of the superconductors, significantly reduces the burnout risk associated with non-uniformity often existing within the volume of superconductor materials. The fault current limiter modules may be electrically coupled together to form various "n" (rows).times."m" (columns) matrix configurations.

  1. Electropneumatic transducer automatically limits motor current

    NASA Technical Reports Server (NTRS)

    Lovitt, T. F.

    1966-01-01

    Pneumatic controller regulates the load on a centrifugal freon compressor in a water cooling system, thus limiting the current input to an electric motor driving it. An electromechanical transducer monitoring the motor input current sends out air signals which indicate changes in the current to the pneumatic controller.

  2. Fault current limiter and alternating current circuit breaker

    DOEpatents

    Boenig, H.J.

    1998-03-10

    A solid-state circuit breaker and current limiter are disclosed for a load served by an alternating current source having a source impedance, the solid-state circuit breaker and current limiter comprising a thyristor bridge interposed between the alternating current source and the load, the thyristor bridge having four thyristor legs and four nodes, with a first node connected to the alternating current source, and a second node connected to the load. A coil is connected from a third node to a fourth node, the coil having an impedance of a value calculated to limit the current flowing therethrough to a predetermined value. Control means are connected to the thyristor legs for limiting the alternating current flow to the load under fault conditions to a predetermined level, and for gating the thyristor bridge under fault conditions to quickly reduce alternating current flowing therethrough to zero and thereafter to maintain the thyristor bridge in an electrically open condition preventing the alternating current from flowing therethrough for a predetermined period of time. 9 figs.

  3. Fault current limiter and alternating current circuit breaker

    DOEpatents

    Boenig, Heinrich J.

    1998-01-01

    A solid-state circuit breaker and current limiter for a load served by an alternating current source having a source impedance, the solid-state circuit breaker and current limiter comprising a thyristor bridge interposed between the alternating current source and the load, the thyristor bridge having four thyristor legs and four nodes, with a first node connected to the alternating current source, and a second node connected to the load. A coil is connected from a third node to a fourth node, the coil having an impedance of a value calculated to limit the current flowing therethrough to a predetermined value. Control means are connected to the thyristor legs for limiting the alternating current flow to the load under fault conditions to a predetermined level, and for gating the thyristor bridge under fault conditions to quickly reduce alternating current flowing therethrough to zero and thereafter to maintain the thyristor bridge in an electrically open condition preventing the alternating current from flowing therethrough for a predetermined period of time.

  4. Addressing Pricing Power in Integrated Delivery: The Limits of Antitrust.

    PubMed

    Berenson, Robert

    2015-08-01

    Prices are the major driver of why the United States spends so much more on health care than other countries do. The pricing power that hospitals have garnered recently has resulted from consolidated delivery systems and concentrated markets, leading to enhanced negotiating leverage. But consolidation may be the wrong frame for viewing the problem of high and highly variable prices; many "must-have" hospitals achieve their pricing power from sources other than consolidation, for example, reputation. Further, the frame of consolidation leads to unrealistic expectations for what antitrust's role in addressing pricing power should be, especially because in the wake of two periods of merger "manias" and "frenzies" many markets already lack effective competition. It is particularly challenging for antitrust to address extant monopolies lawfully attained. New payment and delivery models being pioneered in Medicare, especially those built around accountable care organizations (ACOs), offer an opportunity to reduce pricing power, but only if they are implemented with a clear eye on the impact on prices in commercial insurance markets. This article proposes approaches that public and private payers should consider to complement the role of antitrust to assure that ACOs will actually help control costs in commercial markets as well as in Medicare and Medicaid. PMID:26124302

  5. Addressing Pricing Power in Integrated Delivery: The Limits of Antitrust.

    PubMed

    Berenson, Robert

    2015-08-01

    Prices are the major driver of why the United States spends so much more on health care than other countries do. The pricing power that hospitals have garnered recently has resulted from consolidated delivery systems and concentrated markets, leading to enhanced negotiating leverage. But consolidation may be the wrong frame for viewing the problem of high and highly variable prices; many "must-have" hospitals achieve their pricing power from sources other than consolidation, for example, reputation. Further, the frame of consolidation leads to unrealistic expectations for what antitrust's role in addressing pricing power should be, especially because in the wake of two periods of merger "manias" and "frenzies" many markets already lack effective competition. It is particularly challenging for antitrust to address extant monopolies lawfully attained. New payment and delivery models being pioneered in Medicare, especially those built around accountable care organizations (ACOs), offer an opportunity to reduce pricing power, but only if they are implemented with a clear eye on the impact on prices in commercial insurance markets. This article proposes approaches that public and private payers should consider to complement the role of antitrust to assure that ACOs will actually help control costs in commercial markets as well as in Medicare and Medicaid.

  6. Influence of longitudinal temperature distribution on current limiting function of Superconducting Fault Current Limiting Cable (SFCLC)

    NASA Astrophysics Data System (ADS)

    Kojima, H.; Osawa, T.; Hayakawa, N.; Hanai, M.; Okubo, H.

    2014-05-01

    We have proposed a Superconducting Fault Current Limiting Cable (SFCLC), which is an HTS cable with fault current limiting function. SFCLC is expected to limit the fault current and also immediately recover the cable function after the fault clearance. In the SFCLC operation, a longitudinal temperature distribution will exist due to heat penetration, AC loss, dielectric loss and the performance of cryocooling system, which will influence its current limitation characteristics. In this paper, we investigate the influence of the longitudinal temperature distribution on current limiting function and temperature rise after the current limitation of SFCLC. We suggested the effective measures of parameter control, i.e. decreasing the critical current (Ic@77K), n value at flux flow region (n1-0), increasing the coefficient of longitudinal temperature gradient (α), inflow temperature (Tin) to achieve both the higher current limiting function and the lower temperature rise.

  7. Superconducting fault current limiter for railway transport

    NASA Astrophysics Data System (ADS)

    Fisher, L. M.; Alferov, D. F.; Akhmetgareev, M. R.; Budovskii, A. I.; Evsin, D. V.; Voloshin, I. F.; Kalinov, A. V.

    2015-12-01

    A resistive switching superconducting fault current limiter (SFCL) for DC networks with voltage of 3.5 kV and nominal current of 2 kA is developed. The SFCL consists of two series-connected units: block of superconducting modules and high-speed vacuum breaker with total disconnection time not more than 8 ms. The results of laboratory tests of superconducting SFCL modules in current limiting mode are presented. The recovery time of superconductivity is experimentally determined. The possibility of application of SFCL on traction substations of Russian Railways is considered.

  8. Superconducting fault current limiter for railway transport

    SciTech Connect

    Fisher, L. M. Alferov, D. F.; Akhmetgareev, M. R.; Budovskii, A. I.; Evsin, D. V.; Voloshin, I. F.; Kalinov, A. V.

    2015-12-15

    A resistive switching superconducting fault current limiter (SFCL) for DC networks with voltage of 3.5 kV and nominal current of 2 kA is developed. The SFCL consists of two series-connected units: block of superconducting modules and high-speed vacuum breaker with total disconnection time not more than 8 ms. The results of laboratory tests of superconducting SFCL modules in current limiting mode are presented. The recovery time of superconductivity is experimentally determined. The possibility of application of SFCL on traction substations of Russian Railways is considered.

  9. Current limiting remote power control module

    NASA Technical Reports Server (NTRS)

    Hopkins, Douglas C.

    1990-01-01

    The power source for the Space Station Freedom will be fully utilized nearly all of the time. As such, any loads on the system will need to operate within expected limits. Should any load draw an inordinate amount of power, the bus voltage for the system may sag and disrupt the operation of other loads. To protect the bus and loads some type of power interface between the bus and each load must be provided. This interface is most crucial when load faults occur. A possible system configuration is presented. The proposed interface is the Current Limiting Remote Power Controller (CL-RPC). Such an interface should provide the following power functions: limit overloading and resulting undervoltage; prevent catastrophic failure and still provide for redundancy management within the load; minimize cable heating; and provide accurate current measurement. A functional block diagram of the power processing stage of a CL-RPC is included. There are four functions that drive the circuit design: rate control of current; current sensing; the variable conductance switch (VCS) technology; and the algorithm used for current limiting. Each function is discussed separately.

  10. Protecting the confidentiality of interim data: addressing current challenges.

    PubMed

    Fleming, Thomas R

    2015-02-01

    There is compelling evidence supporting the importance of maintaining confidentiality of interim data in clinical trials designed to reliably address the benefit-to-risk profile of interventions. While this is widely recognized, creative approaches are needed to achieve this in challenging settings where interim data are released for regulatory review and action, even though the trial would be continued to address its primary hypothesis. An illustration is the recently emerging setting of cardiovascular safety trials in type 2 diabetes mellitus. At the first stage of such trials, if large relative increases in cardiovascular major morbidity/mortality can be ruled out, data can be released solely for the purpose of allowing regulatory decision making about marketing approval. The trial is then continued in the post-marketing setting to address the primary hypothesis regarding whether smaller relative increases can be ruled out. Active rather than passive approaches are needed to protect the integrity of cardiovascular safety trials. Given the importance to trial integrity of maintaining confidentiality of interim data such as the estimated relative effect on cardiovascular risk, a Data Access Plan should be in place in these trials to ensure such data are not revealed to study participants and their caregivers, investigators involved in trial conduct, the sponsor's management team, and the public, until trial completion. A Performance Standards Document also should be developed to pre-specify targeted and minimally acceptable levels for recruitment rate, best real-world achievable adherence, avoidance of cross-ins, and retention rate. This document should specify creative approaches for achieving these targets, oversight procedures during trial conduct to monitor performance levels, and actions to be taken if emerging data indicate minimally acceptable levels are not being reached. In settings where meaningful breaches in confidentiality have occurred, such

  11. Protecting the confidentiality of interim data: addressing current challenges.

    PubMed

    Fleming, Thomas R

    2015-02-01

    There is compelling evidence supporting the importance of maintaining confidentiality of interim data in clinical trials designed to reliably address the benefit-to-risk profile of interventions. While this is widely recognized, creative approaches are needed to achieve this in challenging settings where interim data are released for regulatory review and action, even though the trial would be continued to address its primary hypothesis. An illustration is the recently emerging setting of cardiovascular safety trials in type 2 diabetes mellitus. At the first stage of such trials, if large relative increases in cardiovascular major morbidity/mortality can be ruled out, data can be released solely for the purpose of allowing regulatory decision making about marketing approval. The trial is then continued in the post-marketing setting to address the primary hypothesis regarding whether smaller relative increases can be ruled out. Active rather than passive approaches are needed to protect the integrity of cardiovascular safety trials. Given the importance to trial integrity of maintaining confidentiality of interim data such as the estimated relative effect on cardiovascular risk, a Data Access Plan should be in place in these trials to ensure such data are not revealed to study participants and their caregivers, investigators involved in trial conduct, the sponsor's management team, and the public, until trial completion. A Performance Standards Document also should be developed to pre-specify targeted and minimally acceptable levels for recruitment rate, best real-world achievable adherence, avoidance of cross-ins, and retention rate. This document should specify creative approaches for achieving these targets, oversight procedures during trial conduct to monitor performance levels, and actions to be taken if emerging data indicate minimally acceptable levels are not being reached. In settings where meaningful breaches in confidentiality have occurred, such

  12. Flexible moldable conductive current-limiting materials

    SciTech Connect

    Shea, John Joseph; Djordjevic, Miomir B.; Hanna, William Kingston

    2002-01-01

    A current limiting PTC device (10) has two electrodes (14) with a thin film of electric conducting polymer material (20) disposed between the electrodes, the polymer material (20) having superior flexibility and short circuit performance, where the polymer material contains short chain aliphatic diepoxide, conductive filler particles, curing agent, and, preferably, a minor amount of bisphenol A epoxy resin.

  13. Current limiting of field emitter array cathodes

    SciTech Connect

    Lee, K.J.

    1986-01-01

    The Field Emitter Array (FEA) cathode possesses high emission potential (approx.30A/cm/sup 2/) at low applied voltages (100-200 volts) but performance has been hampered by non-uniform emission across the array. Poor emission uniformity is mainly related to small variations in emitter tip geometry (of the order of 10-100A), which cannot be rectified by present fabrication techniques. To improve emission uniformity from the arrays, this dissertation investigated the use of current-limiting resistors, individually dedicated to and in series with each emitter, to compensate for the differences in emission. A thin film of silicon was deposited on the backside of a ZrO/sub 2/-W composite chip (the substrate on which emitter structure was based) to form series resistors. Characterization of the silicon film was carried out in a SEM with a micromanipulator capable of making contact with a single tungsten pin so that direct I-V measurement of individual series resistors was possible. To supplement the experimental effort, a mathematical mode of the Current-Limited Field Emitter Array (CLFEA) cathode was devised. A study of the model indicated the Fowler-Nordheim (F-N) plot of resistor current-limited emission from an array would have an upturning curvature.

  14. Novel 3-Phase Inductive Fault Current Limiter

    NASA Astrophysics Data System (ADS)

    Kosa, Janos

    The paper describes the inductive three-phase fault current limiter. In this work I examine the novel arrangements of the perfect closed superconducting loop made of HTS wire. I applied one iron core with 3 limbs and special loops for uniform temperature of the superconducting wire. In this work I present the results of my experiments with this device. I present the static and dynamic measured results of this solution. It has got several advantages e. g. fast switching and less fault power for high-power electric machines. The advantage of the equipment is that in the case of single-phase short circuit the current will decrease in all the three phases. This can be an appropriate solution for high power machines. For example, in the case of high-power electric motor if there is a single-phase breaking or a single phase short circuit, we can decrease the current in the three phases.

  15. Superconducting Fault Current Limiter for Transmission Voltage

    NASA Astrophysics Data System (ADS)

    Kraemer, Hans-Peter; Schmidt, Wolfgang; Cai, Hong; Gamble, Bruce; Madura, David; MacDonald, Tim; McNamara, Joe; Romanosky, Walther; Snitchler, Greg; Lallouet, Nicolas; Schmidt, Frank; Ahmed, Syed

    Within a collaboration of American Superconductor, Siemens, Nexans and Southern California Edison one electrical phase of a resistive superconducting fault current limiter for the 115 kV transmission voltage level has been designed and manufactured. The active part of the limiter consists of 63 bifilar coils made of 12 mm wide steel-stabilized YBCO conductor and is housed in a cryostat operated at 5 bar and 74 K. The first phase was completely assembled and successfully subjected to power switching tests and high voltage tests. The basic design of the system and the test results are reported. The work was funded in part by US-DOE under Contract Number DE-FC26-07NT43243.

  16. Superconducting Fault Current Limiter optimized design

    NASA Astrophysics Data System (ADS)

    Tixador, Pascal; Badel, Arnaud

    2015-11-01

    The SuperConducting Fault Current Limiter (SCFCL) appears as one of the most promising SC applications for the electrical grids. Despite its advantages and many successful field experiences the market of SCFCL has difficulties to take off even if the first orders for permanent operation in grids are taken. The analytical design of resistive SCFCL will be discussed with the objective to reduce the quantity of SC conductor (length and section) to be more cost-effective. For that the SC conductor must have a high resistivity in normal state. It can be achieved by using high resistivity alloy for shunt, such as Hastelloy®. One of the most severe constraint is that the SCFCL should operate safely for any faults, especially those with low prospective short-circuit currents. This constraint requires to properly design the thickness of the SC tape in order to limit the hot spot temperature. An operation at 65 K appears as very interesting since it decreases the SC cost at least by a factor 2 with a simple LN2 cryogenics. Taking into account the cost reduction in a near future, the SC conductor cost could be rather low, half a dollar per kV A.

  17. Current limiting level-time characteristic of a superconducting fault current limiter

    NASA Astrophysics Data System (ADS)

    Tang, Y. J.; Yokomizu, Y.; Hayakawa, N.; Matsumura, T.; Okubo, H.; Kito, Y.

    A model superconducting fault current limiter (SE-FCL) has been developed. The adopted superconducting cable is composed of six strands insulated from each other. The current limiting level of the SC-FCL is measured under two types of overcurrent, a sinusoidal and an inrush current. The results show that the current limiting level of the SC-FCL Iq increases with an increase in the rate of rise of the overcurrent. By introducing a new parameter of time-to-quench tf, it is found that Iq increases with decreasing tf. This feature is taken as a current limiting level-time characteristic i.e. the Iq- tf characteristic. The existence of the Iq- tf characteristic found in the SC-FCL is qualitatively explained by measuring current distribution among the six strands. The superconducting cable is driven to the normal state strand by strand. Some delay in time is found from the quench of the first strand to that of the last and this is recognized as an Iq- tf characteristic in its current limiting performance.

  18. Self field triggered superconducting fault current limiter

    DOEpatents

    Tekletsadik, Kasegn D.

    2008-02-19

    A superconducting fault current limiter array with a plurality of superconductor elements arranged in a meanding array having an even number of supconductors parallel to each other and arranged in a plane that is parallel to an odd number of the plurality of superconductors, where the odd number of supconductors are parallel to each other and arranged in a plane that is parallel to the even number of the plurality of superconductors, when viewed from a top view. The even number of superconductors are coupled at the upper end to the upper end of the odd number of superconductors. A plurality of lower shunt coils each coupled to the lower end of each of the even number of superconductors and a plurality of upper shunt coils each coupled to the upper end of each of the odd number of superconductors so as to generate a generally orthoganal uniform magnetic field during quenching using only the magenetic field generated by the superconductors.

  19. 5 CFR Appendix A to 5 Cfr Chapter... - Current Addresses and Geographic Jurisdictions

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Current Addresses and Geographic Jurisdictions A Appendix A to 5 CFR Chapter XIV Administrative Personnel FEDERAL LABOR RELATIONS AUTHORITY.... A Appendix A to 5 CFR Chapter XIV—Current Addresses and Geographic Jurisdictions (a) The...

  20. Inrush-Current Limiter And Bus Isolator

    NASA Technical Reports Server (NTRS)

    Dolland, Carlisle R.

    1994-01-01

    Electronic circuit protects electrical power bus and source of power against excessive current demands. Circuit intended for use with power-consuming electronic system drawing pulsed currents and including capacitor bank as low-impedance secondary source from which pulsed currents drawn.

  1. Limitations in small artisanal gold mining addressed by educational components paired with alternative mining methods.

    PubMed

    Zolnikov, Tara R

    2012-03-01

    Current solutions continue to be inadequate in addressing the longstanding, worldwide problem of mercury emissions from small artisanal gold mining. Mercury, an inexpensive and easily accessible heavy metal, is used in the process of extracting gold from ore. Mercury emissions disperse, affecting human populations by causing adverse health effects and environmental and social ramifications. Many developing nations have sizable gold ore deposits, making small artisanal gold mining a major source of employment in the world. Poverty drives vulnerable, rural populations into gold mining because of social and economic instabilities. Educational programs responding to this environmental hazard have been implemented in the past, but have had low positive results due to lack of governmental support and little economic incentive. Educational and enforced intervention programs must be developed in conjunction with governmental agencies in order to successfully eliminate this ongoing problem. Industry leaders offered hopeful suggestions, but revealed limitations when trying to develop encompassing solutions to halt mercury emissions. This research highlights potential options that have been attempted in the past and suggests alternative solutions to improve upon these methods. Some methods include buyer impact recognition, risk assessment proposals exposing a cost-benefit analysis and toxicokinetic modeling, public health awareness campaigns, and the education of miners, healthcare workers, and locals within hazardous areas of mercury exposure. These methods, paired with the implementation of alternative mining techniques, propose a substantial reduction of mercury emissions.

  2. Current Status and Research into Overcoming Limitations of Capsule Endoscopy

    PubMed Central

    Kwack, Won Gun; Lim, Yun Jeong

    2016-01-01

    Endoscopic investigation has a critical role in the diagnosis and treatment of gastrointestinal (GI) diseases. Since 2001, capsule endoscopy (CE) has been available for small-bowel exploration and is under continuous development. During the past decade, CE has achieved impressive improvements in areas such as miniaturization, resolution, and battery life. As a result, CE is currently a first-line tool for the investigation of the small bowel in obscure gastrointestinal bleeding and is a useful alternative to wired enteroscopy. Nevertheless, CE still has several limitations, such as incomplete examination and limited diagnostic and therapeutic capabilities. To resolve these problems, many groups have suggested several models (e.g., controlled CO2 insufflation system, magnetic navigation system, mobile robotic platform, tagging and biopsy equipment, and targeted drug-delivery system), which are in development. In the near future, new technological advances will improve the capabilities of CE and broaden its spectrum of applications not only for the small bowel but also for the colon, stomach, and esophagus. The purpose of this review is to introduce the current status of CE and to review the ongoing development of solutions to address its limitations. PMID:26855917

  3. Is current biochar soil study addressing global soil constraints for sustainable agriculture?

    NASA Astrophysics Data System (ADS)

    Pan, Genxing; Zhang, Dengxiao; Yan, Ming; Niu, Yaru; Liu, Xiaoyu; van Zwieten, Lukas; Chen, De; Bian, Rongjun; Cheng, Kun; Li, Lianqing; Joseph, Stephen; Zheng, Jinwei; Zhang, Xuhui; Zheng, Jufeng; Crowley, David; Filley, Timothy

    2016-04-01

    Global soil degradation has been increasingly threatened sustainability of world agriculture. Use of biochar from bio-wastes has been proposed as a global option for its great potential in tackling soil degradation and mitigating climate change in agriculture. For last 10 years, there have been greatly increasing interests in application of charred biomass, more recently termed biochar, as a soil amendment for addressing soil constraints for sustainable agriculture. Biochar soil studies could deliver reliable information for appropriate application of biochar to soils where for sustainable agriculture has been challenged. Here we review the literature of 798 publications reporting biochar soil studies by August, 2015 to address potential gaps in understanding of biochar's role in agriculture. We have found some substantial biases and gaps inherent in the current biochar studies. 1) The majority of published studies were from developed regions where the soils are less constrained and were much more frequent in laboratory and glasshouse pot experiments than field studies under realistic agriculture. 2) The published biochar soil studies have used more often small kiln or lab prepared biochar than commercial scale biochars, more often wood and municipal waste derived biochars than crop straw biochars. Overall, the lack of long-term well designed field studies using biochar produced in commercial processes may have limited our current understanding of biochar's potential to enhance global crop production and climate change mitigation. We have also recommended a global alliance between longer-term research experiments and biochar production facilities to foster the uptake of this important technology at a global scale. Keywords: biochar, soil study, literature review, research gap, global perspective, quantitative assessment, sustainable agriculture

  4. Laparoscopic liver resection: Current role and limitations.

    PubMed

    Mostaedi, Rouzbeh; Milosevic, Zoran; Han, Ho-Seong; Khatri, Vijay P

    2012-08-15

    Laparoscopic liver resection (LLR) for the treatment of benign and malignant liver lesions is often performed at specialized centers. Technological advances, such as laparoscopic ultrasonography and electrosurgical tools, have afforded surgeons simultaneous improvements in surgical technique. The utilization of minimally invasive techniques for liver resection has been reported to reduce operative time, decrease blood loss, and shorten length of hospital stay with equivalent postoperative mortality and morbidity rates compared to open liver resection (OLR). Non-anatomic liver resection and left lateral sectionectomy are now routinely performed laparoscopically at many institutions. Furthermore, major hepatic resections are performed by pure laparoscopy, hand-assisted technique, and the hybrid method. In addition, robotic surgery and single port surgery are revealing early promising results. The consensus recommendation for the treatment of benign liver disease and malignant lesions remains unchanged when considering a laparoscopic approach, except when comorbidities and anatomic limitations of the liver lesion preclude this technique. Disease free and survival rates after LLR for hepatocellular carcinoma and metastatic colon cancer correspond to OLR. Patient selection is a significant factor for these favorable outcomes. The limitations include LLR of superior and posterior liver lesions; however, adjustments in technique may now consider a laparoscopic approach as a viable option. As growing data continue to reveal the feasibility and efficacy of laparoscopic liver surgery, this skill is increasingly being adopted by hepatobiliary surgeons. Although the full scope of laparoscopic liver surgery remains infrequently used by many general surgeons, this technique will become a standard in the treatment of liver diseases as studies continue to show favorable outcomes.

  5. Fault current limiter with shield and adjacent cores

    DOEpatents

    Darmann, Francis Anthony; Moriconi, Franco; Hodge, Eoin Patrick

    2013-10-22

    In a fault current limiter (FCL) of a saturated core type having at least one coil wound around a high permeability material, a method of suppressing the time derivative of the fault current at the zero current point includes the following step: utilizing an electromagnetic screen or shield around the AC coil to suppress the time derivative current levels during zero current conditions.

  6. Current parallel I/O limitations to scalable data analysis.

    SciTech Connect

    Mascarenhas, Ajith Arthur; Pebay, Philippe Pierre

    2011-07-01

    This report describes the limitations to parallel scalability which we have encountered when applying our otherwise optimally scalable parallel statistical analysis tool kit to large data sets distributed across the parallel file system of the current premier DOE computational facility. This report describes our study to evaluate the effect of parallel I/O on the overall scalability of a parallel data analysis pipeline using our scalable parallel statistics tool kit [PTBM11]. In this goal, we tested it using the Jaguar-pf DOE/ORNL peta-scale platform on a large combustion simulation data under a variety of process counts and domain decompositions scenarios. In this report we have recalled the foundations of the parallel statistical analysis tool kit which we have designed and implemented, with the specific double intent of reproducing typical data analysis workflows, and achieving optimal design for scalable parallel implementations. We have briefly reviewed those earlier results and publications which allow us to conclude that we have achieved both goals. However, in this report we have further established that, when used in conjuction with a state-of-the-art parallel I/O system, as can be found on the premier DOE peta-scale platform, the scaling properties of the overall analysis pipeline comprising parallel data access routines degrade rapidly. This finding is problematic and must be addressed if peta-scale data analysis is to be made scalable, or even possible. In order to attempt to address these parallel I/O limitations, we will investigate the use the Adaptable IO System (ADIOS) [LZL+10] to improve I/O performance, while maintaining flexibility for a variety of IO options, such MPI IO, POSIX IO. This system is developed at ORNL and other collaborating institutions, and is being tested extensively on Jaguar-pf. Simulation code being developed on these systems will also use ADIOS to output the data thereby making it easier for other systems, such as ours, to

  7. 5 CFR Appendix A to 5 Cfr Chapter... - Current Addresses and Geographic Jurisdictions

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Jurisdictions A Appendix A to 5 CFR Chapter XIV Administrative Personnel FEDERAL LABOR RELATIONS AUTHORITY.... A Appendix A to 5 CFR Chapter XIV—Current Addresses and Geographic Jurisdictions (a) The Office... land and water areas west of the continents of North and South America (except coastal islands) to...

  8. 5 CFR Appendix A to 5 Cfr Chapter... - Current Addresses and Geographic Jurisdictions

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Jurisdictions A Appendix A to 5 CFR Chapter XIV Administrative Personnel FEDERAL LABOR RELATIONS AUTHORITY.... A Appendix A to 5 CFR Chapter XIV—Current Addresses and Geographic Jurisdictions (a) The Office... land and water areas west of the continents of North and South America (except coastal islands) to...

  9. 5 CFR Appendix A to 5 Cfr Chapter... - Current Addresses and Geographic Jurisdictions

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Jurisdictions A Appendix A to 5 CFR Chapter XIV Administrative Personnel FEDERAL LABOR RELATIONS AUTHORITY.... A Appendix A to 5 CFR Chapter XIV—Current Addresses and Geographic Jurisdictions (a) The Office... land and water areas west of the continents of North and South America (except coastal islands) to...

  10. 5 CFR Appendix A to 5 Cfr Chapter... - Current Addresses and Geographic Jurisdictions

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Jurisdictions A Appendix A to 5 CFR Chapter XIV Administrative Personnel FEDERAL LABOR RELATIONS AUTHORITY.... A Appendix A to 5 CFR Chapter XIV—Current Addresses and Geographic Jurisdictions (a) The Office... land and water areas west of the continents of North and South America (except coastal islands) to...

  11. Nondestructive test determines overload destruction characteristics of current limiter fuses

    NASA Technical Reports Server (NTRS)

    Swartz, G. A.

    1968-01-01

    Nondestructive test predicts the time required for current limiters to blow /open the circuit/ when subjected to a given overload. The test method is based on an empirical relationship between the voltage rise across a current limiter for a fixed time interval and the time to blow.

  12. Maximum time-dependent space-charge limited diode currents

    NASA Astrophysics Data System (ADS)

    Griswold, M. E.; Fisch, N. J.

    2016-01-01

    Recent papers claim that a one dimensional (1D) diode with a time-varying voltage drop can transmit current densities that exceed the Child-Langmuir (CL) limit on average, apparently contradicting a previous conjecture that there is a hard limit on the average current density across any 1D diode, as t → ∞, that is equal to the CL limit. However, these claims rest on a different definition of the CL limit, namely, a comparison between the time-averaged diode current and the adiabatic average of the expression for the stationary CL limit. If the current were considered as a function of the maximum applied voltage, rather than the average applied voltage, then the original conjecture would not have been refuted.

  13. Current-limiting challenges for all-spin logic devices.

    PubMed

    Su, Li; Zhang, Youguang; Klein, Jacques-Olivier; Zhang, Yue; Bournel, Arnaud; Fert, Albert; Zhao, Weisheng

    2015-01-01

    All-spin logic device (ASLD) has attracted increasing interests as one of the most promising post-CMOS device candidates, thanks to its low power, non-volatility and logic-in-memory structure. Here we investigate the key current-limiting factors and develop a physics-based model of ASLD through nano-magnet switching, the spin transport properties and the breakdown characteristic of channel. First, ASLD with perpendicular magnetic anisotropy (PMA) nano-magnet is proposed to reduce the critical current (Ic0). Most important, the spin transport efficiency can be enhanced by analyzing the device structure, dimension, contact resistance as well as material parameters. Furthermore, breakdown current density (JBR) of spin channel is studied for the upper current limitation. As a result, we can deduce current-limiting conditions and estimate energy dissipation. Based on the model, we demonstrate ASLD with different structures and channel materials (graphene and copper). Asymmetric structure is found to be the optimal option for current limitations. Copper channel outperforms graphene in term of energy but seriously suffers from breakdown current limit. By exploring the current limit and performance tradeoffs, the optimization of ASLD is also discussed. This benchmarking model of ASLD opens up new prospects for design and implementation of future spintronics applications.

  14. Current-limiting challenges for all-spin logic devices

    NASA Astrophysics Data System (ADS)

    Su, Li; Zhang, Youguang; Klein, Jacques-Olivier; Zhang, Yue; Bournel, Arnaud; Fert, Albert; Zhao, Weisheng

    2015-10-01

    All-spin logic device (ASLD) has attracted increasing interests as one of the most promising post-CMOS device candidates, thanks to its low power, non-volatility and logic-in-memory structure. Here we investigate the key current-limiting factors and develop a physics-based model of ASLD through nano-magnet switching, the spin transport properties and the breakdown characteristic of channel. First, ASLD with perpendicular magnetic anisotropy (PMA) nano-magnet is proposed to reduce the critical current (Ic0). Most important, the spin transport efficiency can be enhanced by analyzing the device structure, dimension, contact resistance as well as material parameters. Furthermore, breakdown current density (JBR) of spin channel is studied for the upper current limitation. As a result, we can deduce current-limiting conditions and estimate energy dissipation. Based on the model, we demonstrate ASLD with different structures and channel materials (graphene and copper). Asymmetric structure is found to be the optimal option for current limitations. Copper channel outperforms graphene in term of energy but seriously suffers from breakdown current limit. By exploring the current limit and performance tradeoffs, the optimization of ASLD is also discussed. This benchmarking model of ASLD opens up new prospects for design and implementation of future spintronics applications.

  15. Current-limiting challenges for all-spin logic devices

    PubMed Central

    Su, Li; Zhang, Youguang; Klein, Jacques-Olivier; Zhang, Yue; Bournel, Arnaud; Fert, Albert; Zhao, Weisheng

    2015-01-01

    All-spin logic device (ASLD) has attracted increasing interests as one of the most promising post-CMOS device candidates, thanks to its low power, non-volatility and logic-in-memory structure. Here we investigate the key current-limiting factors and develop a physics-based model of ASLD through nano-magnet switching, the spin transport properties and the breakdown characteristic of channel. First, ASLD with perpendicular magnetic anisotropy (PMA) nano-magnet is proposed to reduce the critical current (Ic0). Most important, the spin transport efficiency can be enhanced by analyzing the device structure, dimension, contact resistance as well as material parameters. Furthermore, breakdown current density (JBR) of spin channel is studied for the upper current limitation. As a result, we can deduce current-limiting conditions and estimate energy dissipation. Based on the model, we demonstrate ASLD with different structures and channel materials (graphene and copper). Asymmetric structure is found to be the optimal option for current limitations. Copper channel outperforms graphene in term of energy but seriously suffers from breakdown current limit. By exploring the current limit and performance tradeoffs, the optimization of ASLD is also discussed. This benchmarking model of ASLD opens up new prospects for design and implementation of future spintronics applications. PMID:26449410

  16. Advances in addressing technical challenges of point-of-care diagnostics in resource-limited settings

    PubMed Central

    Wang, ShuQi; Lifson, Mark A.; Inci, Fatih; Liang, Li-Guo; Sheng, Ye-Feng; Demirci, Utkan

    2016-01-01

    The striking prevalence of HIV, TB and malaria, as well as outbreaks of emerging infectious diseases, such as influenza A (H7N9), Ebola and MERS, poses great challenges for patient care in resource-limited settings (RLS). However, advanced diagnostic technologies cannot be implemented in RLS largely due to economic constraints. Simple and inexpensive point-of-care (POC) diagnostics, which rely less on environmental context and operator training, have thus been extensively studied to achieve early diagnosis and treatment monitoring in non-laboratory settings. Despite great input from material science, biomedical engineering and nanotechnology for developing POC diagnostics, significant technical challenges are yet to be overcome. Summarized here are the technical challenges associated with POC diagnostics from a RLS perspective and the latest advances in addressing these challenges are reviewed. PMID:26777725

  17. Tools for address georeferencing - limitations and opportunities every public health professional should be aware of.

    PubMed

    Ribeiro, Ana Isabel; Olhero, Andreia; Teixeira, Hugo; Magalhães, Alexandre; Pina, Maria Fátima

    2014-01-01

    Various address georeferencing (AG) tools are currently available. But little is known about the quality of each tool. Using data from the EPIPorto cohort we compared the most commonly used AG tools in terms of positional error (PE) and subjects' misclassification according to census tract socioeconomic status (SES), a widely used variable in epidemiologic studies. Participants of the EPIPorto cohort (n = 2427) were georeferenced using Geographical Information Systems (GIS) and Google Earth (GE). One hundred were randomly selected and georeferenced using three additional tools: 1) cadastral maps (gold-standard); 2) Global Positioning Systems (GPS) and 3) Google Earth, single and in a batch. Mean PE and the proportion of misclassified individuals were compared. Google Earth showed lower PE than GIS, but 10% of the addresses were imprecisely positioned. Thirty-eight, 27, 16 and 14% of the participants were located in the wrong census tract by GIS, GPS, GE (batch) and GE (single), respectively (p<0.001). Misclassification according to SES was less frequent but still non-negligible -14.4, 8.1, 4.2 and 2% (p<0.001). The quality of georeferencing differed substantially between AG tools. GE seems to be the best tool, but only if prudently used. Epidemiologic studies using spatial data should start including information on the quality and accuracy of their georeferencing tools and spatial datasets. PMID:25469514

  18. Tools for Address Georeferencing – Limitations and Opportunities Every Public Health Professional Should Be Aware Of

    PubMed Central

    Ribeiro, Ana Isabel; Olhero, Andreia; Teixeira, Hugo; Magalhães, Alexandre; Pina, Maria Fátima

    2014-01-01

    Various address georeferencing (AG) tools are currently available. But little is known about the quality of each tool. Using data from the EPIPorto cohort we compared the most commonly used AG tools in terms of positional error (PE) and subjects' misclassification according to census tract socioeconomic status (SES), a widely used variable in epidemiologic studies. Participants of the EPIPorto cohort (n = 2427) were georeferenced using Geographical Information Systems (GIS) and Google Earth (GE). One hundred were randomly selected and georeferenced using three additional tools: 1) cadastral maps (gold-standard); 2) Global Positioning Systems (GPS) and 3) Google Earth, single and in a batch. Mean PE and the proportion of misclassified individuals were compared. Google Earth showed lower PE than GIS, but 10% of the addresses were imprecisely positioned. Thirty-eight, 27, 16 and 14% of the participants were located in the wrong census tract by GIS, GPS, GE (batch) and GE (single), respectively (p<0.001). Misclassification according to SES was less frequent but still non-negligible −14.4, 8.1, 4.2 and 2% (p<0.001). The quality of georeferencing differed substantially between AG tools. GE seems to be the best tool, but only if prudently used. Epidemiologic studies using spatial data should start including information on the quality and accuracy of their georeferencing tools and spatial datasets. PMID:25469514

  19. Tools for address georeferencing - limitations and opportunities every public health professional should be aware of.

    PubMed

    Ribeiro, Ana Isabel; Olhero, Andreia; Teixeira, Hugo; Magalhães, Alexandre; Pina, Maria Fátima

    2014-01-01

    Various address georeferencing (AG) tools are currently available. But little is known about the quality of each tool. Using data from the EPIPorto cohort we compared the most commonly used AG tools in terms of positional error (PE) and subjects' misclassification according to census tract socioeconomic status (SES), a widely used variable in epidemiologic studies. Participants of the EPIPorto cohort (n = 2427) were georeferenced using Geographical Information Systems (GIS) and Google Earth (GE). One hundred were randomly selected and georeferenced using three additional tools: 1) cadastral maps (gold-standard); 2) Global Positioning Systems (GPS) and 3) Google Earth, single and in a batch. Mean PE and the proportion of misclassified individuals were compared. Google Earth showed lower PE than GIS, but 10% of the addresses were imprecisely positioned. Thirty-eight, 27, 16 and 14% of the participants were located in the wrong census tract by GIS, GPS, GE (batch) and GE (single), respectively (p<0.001). Misclassification according to SES was less frequent but still non-negligible -14.4, 8.1, 4.2 and 2% (p<0.001). The quality of georeferencing differed substantially between AG tools. GE seems to be the best tool, but only if prudently used. Epidemiologic studies using spatial data should start including information on the quality and accuracy of their georeferencing tools and spatial datasets.

  20. Natural Limits for Currents in Charge Separated Pulsar Magnetospheres

    NASA Astrophysics Data System (ADS)

    Jessner, A.; Lesch, H.; Kunzl, T.

    Rough estimates and upper limits on current and particle densities form the basis of most of the canonical pulsar models. Whereas the surface of the rotating neutron star is capable of supplying sufficient charges to provide a current that, given the polar cap potential, could easily fuel the observed energy loss processes, observational and theoretical constraints provide strict upper limits to the charge densities. The space charge of a current consisting solely of particles having only one sign creates a compensating potential that will make the maximum current dependent on potential and distance. In the non-relativistic case this fact is expressed in the familiar Child-Langmuir law. Its relativistic generalization and subsequent application to the inner pulsar magnetosphere provides clear limits on the strength and radial extension of charged currents originating on the polar cap. Violent Pierce-type oscillations set in, if one attempts to inject more current than the space charge limit into a given volume. These considerations apply wherever there is a significant amount of charged current flow, in particular in the gap regions. There they can be used to derive limits on the size of such gaps and their stability.

  1. Risk newsboy: approach for addressing uncertainty in developing action levels and cleanup limits

    SciTech Connect

    Cooke, Roger; MacDonell, Margaret

    2007-07-01

    Site cleanup decisions involve developing action levels and residual limits for key contaminants, to assure health protection during the cleanup period and into the long term. Uncertainty is inherent in the toxicity information used to define these levels, based on incomplete scientific knowledge regarding dose-response relationships across various hazards and exposures at environmentally relevant levels. This problem can be addressed by applying principles used to manage uncertainty in operations research, as illustrated by the newsboy dilemma. Each day a newsboy must balance the risk of buying more papers than he can sell against the risk of not buying enough. Setting action levels and cleanup limits involves a similar concept of balancing and distributing risks and benefits in the face of uncertainty. The newsboy approach can be applied to develop health-based target concentrations for both radiological and chemical contaminants, with stakeholder input being crucial to assessing 'regret' levels. Associated tools include structured expert judgment elicitation to quantify uncertainty in the dose-response relationship, and mathematical techniques such as probabilistic inversion and iterative proportional fitting. (authors)

  2. Testing of 3-meter Prototype Fault Current Limiting Cables

    SciTech Connect

    Gouge, Michael J; Duckworth, Robert C; Demko, Jonathan A; Rey, Christopher M; Thompson, James R; Lindsay, David T; Tolbert, Jerry Carlton; Willen, Dag; Lentge, Heidi; Thidemann, Carsten; Carter, Bill

    2009-01-01

    Two 3-m long, single-phase cables have been fabricated by Ultera from second generation (2G) superconductor supplied by American Superconductor. The first cable was made with two layers of 2G tape conductor and had a critical current of 5,750 A while the second cable had four layers and a critical current of 8,500 A. AC loss was measured for both cables at ac currents of up to 4 kArms. Ultera performed initial fault current studies of both cables in Denmark with limited currents in the range from 9.1 to 44 kA. Results from these tests will provide a basis for a 25-m long, three-phase, prototype cable to be tested at ORNL early next year and a 300-m long, fault current limiting, superconducting cable to be installed in a ConEd substation in New York City.

  3. Current limiting mechanisms in electron and ion beam experiments

    NASA Technical Reports Server (NTRS)

    Olsen, R. C.

    1990-01-01

    The emission and collection of current from satellites or rockets in the ionosphere is a process which, at equilibrium, requires a balance between inward and outward currents. In most active experiments in the ionosphere and magnetosphere, the emitted current exceeds the integrated thermal current by one or more orders of magnitude. The system response is typically for the emitted current to be limited by processes such as differential charging of insulating surfaces, interactions between an emitted beam and the local plasma, and interactions between the beam and local neutral gas. These current limiting mechanisms have been illustrated for 20 years in sounding rocket and satellite experiments, which are reviewed here. Detailed presentations of the Spacecraft Charging at High Altitude (SCATHA) electron and ion gun experiments are used to demonstrate the general range of observed phenomena.

  4. In Vivo Demonstration of Addressable Microstimulators Powered by Rectification of Epidermically Applied Currents for Miniaturized Neuroprostheses.

    PubMed

    Becerra-Fajardo, Laura; Ivorra, Antoni

    2015-01-01

    Electrical stimulation is used in order to restore nerve mediated functions in patients with neurological disorders, but its applicability is constrained by the invasiveness of the systems required to perform it. As an alternative to implantable systems consisting of central stimulation units wired to the stimulation electrodes, networks of wireless microstimulators have been devised for fine movement restoration. Miniaturization of these microstimulators is currently hampered by the available methods for powering them. Previously, we have proposed and demonstrated a heterodox electrical stimulation method based on electronic rectification of high frequency current bursts. These bursts can be delivered through textile electrodes on the skin. This approach has the potential to result in an unprecedented level of miniaturization as no bulky parts such as coils or batteries are included in the implant. We envision microstimulators designs based on application-specific integrated circuits (ASICs) that will be flexible, thread-like (diameters < 0.5 mm) and not only with controlled stimulation capabilities but also with sensing capabilities for artificial proprioception. We in vivo demonstrate that neuroprostheses composed of addressable microstimulators based on this electrical stimulation method are feasible and can perform controlled charge-balanced electrical stimulation of muscles. We developed miniature external circuit prototypes connected to two bipolar probes that were percutaneously implanted in agonist and antagonist muscles of the hindlimb of an anesthetized rabbit. The electronic implant architecture was able to decode commands that were amplitude modulated on the high frequency (1 MHz) auxiliary current bursts. The devices were capable of independently stimulating the target tissues, accomplishing controlled dorsiflexion and plantarflexion joint movements. In addition, we numerically show that the high frequency current bursts comply with safety standards

  5. In Vivo Demonstration of Addressable Microstimulators Powered by Rectification of Epidermically Applied Currents for Miniaturized Neuroprostheses

    PubMed Central

    2015-01-01

    Electrical stimulation is used in order to restore nerve mediated functions in patients with neurological disorders, but its applicability is constrained by the invasiveness of the systems required to perform it. As an alternative to implantable systems consisting of central stimulation units wired to the stimulation electrodes, networks of wireless microstimulators have been devised for fine movement restoration. Miniaturization of these microstimulators is currently hampered by the available methods for powering them. Previously, we have proposed and demonstrated a heterodox electrical stimulation method based on electronic rectification of high frequency current bursts. These bursts can be delivered through textile electrodes on the skin. This approach has the potential to result in an unprecedented level of miniaturization as no bulky parts such as coils or batteries are included in the implant. We envision microstimulators designs based on application-specific integrated circuits (ASICs) that will be flexible, thread-like (diameters < 0.5 mm) and not only with controlled stimulation capabilities but also with sensing capabilities for artificial proprioception. We in vivo demonstrate that neuroprostheses composed of addressable microstimulators based on this electrical stimulation method are feasible and can perform controlled charge-balanced electrical stimulation of muscles. We developed miniature external circuit prototypes connected to two bipolar probes that were percutaneously implanted in agonist and antagonist muscles of the hindlimb of an anesthetized rabbit. The electronic implant architecture was able to decode commands that were amplitude modulated on the high frequency (1 MHz) auxiliary current bursts. The devices were capable of independently stimulating the target tissues, accomplishing controlled dorsiflexion and plantarflexion joint movements. In addition, we numerically show that the high frequency current bursts comply with safety standards

  6. Counter-current flow limited CHF in thin rectangular channels

    SciTech Connect

    Cheng, L.Y.

    1990-01-01

    An analytical expression for counter-current-flow-limitation (CCFL) was used to predict critical heat flux (CHF) for downward flow in thin vertical rectangular channels which are prototypes of coolant channels in test and research nuclear reactors. Top flooding is the mechanism for counter-current flow limited CHF. The CCFL correlation also was used to determine the circulation and flooding-limited CHF. Good agreements were observed between the period the model predictions and data on the CHF for downflow. The minimum CHF for downflow is lower than the flooding-limited CHF and it is predicted to occur at a liquid flow rate higher than that at the flooding limit. 17 refs., 7 figs.

  7. Method and apparatus to trigger superconductors in current limiting devices

    DOEpatents

    Yuan, Xing; Hazelton, Drew Willard; Walker, Michael Stephen

    2004-10-26

    A method and apparatus for magnetically triggering a superconductor in a superconducting fault current limiter to transition from a superconducting state to a resistive state. The triggering is achieved by employing current-carrying trigger coil or foil on either or both the inner diameter and outer diameter of a superconductor. The current-carrying coil or foil generates a magnetic field with sufficient strength and the superconductor is disposed within essentially uniform magnetic field region. For superconductor in a tubular-configured form, an additional magnetic field can be generated by placing current-carrying wire or foil inside the tube and along the center axial line.

  8. Fault current limiter with solid-state circuit breakers

    NASA Astrophysics Data System (ADS)

    Bălan, H.; Neamț, L.; Buzdugan, M. I.; Varodi, T.; Pop, E.

    2016-08-01

    Switching of power circuit breakers is an important technical issue, especially at short circuit, since the fault current cause thermal and dynamic stresses, and the power quality worsens. Recently, the development of distributed renewable electricity induces the short circuit protection problematic because the distributed production of electric energy cause the transport networks to lose their radial character and disturbs the protective relays coordination. The modern technologies for power switching uses static fault current limiters, which offers a viable solution to remove the problems caused by large fault currents in the system. An appropriate design of the current limiting device reduces the thermal and dynamic stress and limits the fault current to a low value. The static switches are based on high power semiconductor devices that offer advantages compared to mechanical switches. Using a fault current limiter that minimizes the effect of distributed generation of electricity in a radial network on the co-ordination of protective relays is a solution to this problem in terms of switching speed and lifespan of power switches.

  9. Towards addressable wireless microstimulators based on electronic rectification of epidermically applied currents.

    PubMed

    Becerra-Fajardo, L; Ivorra, A

    2014-01-01

    Electrical stimulation has been explored to restore the capabilities of the nervous system in paralysis patients. This area of research and of clinical practice, known as Functional Electrical Stimulation, would greatly benefit from further miniaturization of implantable stimulators. To that end, we recently proposed and demonstrated an innovative electrical stimulation method in which implanted microstimulators operate as rectifiers of bursts of innocuous high frequency current supplied by skin electrodes, thus generating low frequency currents capable of stimulating excitable tissues. A diode could suffice in some applications but, in order to broaden the method's clinical applicability, we envision rectifiers with advanced capabilities such as current control and addressability. We plan flexible thread-like implants (diameters < 300 μm) containing ASICs. As an intermediate stage, we are developing macroscopic implants (diameters ~ 2 mm) made of off-the-shelf components. Here we present a circuit which responds to commands modulated within the high frequency bursts and which is able to deliver charge-balanced currents. We show that a number of these circuits can perform independent stimulation of segments of an anesthetized earthworm following commands from a computer. PMID:25570862

  10. A current limiter with superconducting coil for magnetic field shielding

    NASA Astrophysics Data System (ADS)

    Kaiho, K.; Yamaguchi, H.; Arai, K.; Umeda, M.; Yamaguchi, M.; Kataoka, T.

    2001-05-01

    The magnetic shield type superconducting fault current limiter have been built and successfully tested in ABB corporate research and so on. The device is essentially a transformer in which the secondary winding is the superconducting tube. However, due to the large AC losses and brittleness of the superconducting bulk tube, they have not yet entered market. A current limiter with superconducting coil for the magnetic field shielding is considered. By using the superconducting coil made by the multi-filamentary high Tc superconductor instead of the superconducting bulk tube, the AC losses can be reduced due to the reduced superconductor thickness and the brittleness of the bulk tube can be avoidable. This paper presents a preliminary consideration of the magnetic shield type superconducting fault current limiter with superconducting coil as secondary winding and their AC losses in comparison to that of superconducting bulk in 50 Hz operation.

  11. Limiting current of intense electron beams in a decelerating gap

    NASA Astrophysics Data System (ADS)

    Nusinovich, G. S.; Beaudoin, B. L.; Thompson, C.; Karakkad, J. A.; Antonsen, T. M.

    2016-02-01

    For numerous applications, it is desirable to develop electron beam driven efficient sources of electromagnetic radiation that are capable of producing the required power at beam voltages as low as possible. This trend is limited by space charge effects that cause the reduction of electron kinetic energy and can lead to electron reflection. So far, this effect was analyzed for intense beams propagating in uniform metallic pipes. In the present study, the limiting currents of intense electron beams are analyzed for the case of beam propagation in the tubes with gaps. A general treatment is illustrated by an example evaluating the limiting current in a high-power, tunable 1-10 MHz inductive output tube (IOT), which is currently under development for ionospheric modification. Results of the analytical theory are compared to results of numerical simulations. The results obtained allow one to estimate the interaction efficiency of IOTs.

  12. Quantum theory of space charge limited current in solids

    SciTech Connect

    González, Gabriel

    2015-02-28

    We present a quantum model of space charge limited current transport inside trap-free solids with planar geometry in the mean field approximation. We use a simple transformation which allows us to find the exact analytical solution for the steady state current case. We use our approach to find a Mott-Gurney like behavior and the mobility for single charge carriers in the quantum regime in solids.

  13. The role of business in addressing the long-term implications of the current food crisis.

    PubMed

    Yach, Derek

    2008-01-01

    Before the onset of the current food crisis, the evidence of a severely neglected nutrition crisis was starting to receive attention. Increased food prices are having severe impacts on the nutritional status of populations. Our current food system has evolved over decades in a largely unplanned manner and without consideration for the complexity and implications of linkages between health, nutrition, agricultural, economic, trade and security issues. The underlying causes for the nutrition crisis include the above, as well as decades of neglect with regard to nutrition, and agricultural science (especially in emerging markets); a failure of governance with respect to the major players involved in nutrition, a weak response by government donors and Foundations to invest in basic nutrition (in contrast to growing support for humanitarian aspects of food aid), and a reluctance to develop private-public partnerships. The emergence of new business models that tackle social problems while remaining profitable offers promise that the long term nutrition needs of people can be met. Businesses can have greater impact acting collectively than individually. Food, retail, food service, chemical and pharmaceutical companies have expertise, distribution systems and customers insights, if well harnessed, could leapfrog progress in addressing the food and nutrition crises. While business can do lots more, its combined impact will be minimal if a range of essential government actions and policies are not addressed. Governments need to create innovative and complementary opportunities that include incentives for businesses including: setting clear nutritional guidelines for fortification and for ready-to eat products; offering agreements to endorse approved products and support their distribution to clinics and schools; eliminating duties on imported vitamins and other micronutrients; and providing tax and other incentives for industry to invest with donors in essential nutrition

  14. The role of business in addressing the long-term implications of the current food crisis

    PubMed Central

    Yach, Derek

    2008-01-01

    Before the onset of the current food crisis, the evidence of a severely neglected nutrition crisis was starting to receive attention. Increased food prices are having severe impacts on the nutritional status of populations. Our current food system has evolved over decades in a largely unplanned manner and without consideration for the complexity and implications of linkages between health, nutrition, agricultural, economic, trade and security issues. The underlying causes for the nutrition crisis include the above, as well as decades of neglect with regard to nutrition, and agricultural science (especially in emerging markets); a failure of governance with respect to the major players involved in nutrition, a weak response by government donors and Foundations to invest in basic nutrition (in contrast to growing support for humanitarian aspects of food aid), and a reluctance to develop private-public partnerships. The emergence of new business models that tackle social problems while remaining profitable offers promise that the long term nutrition needs of people can be met. Businesses can have greater impact acting collectively than individually. Food, retail, food service, chemical and pharmaceutical companies have expertise, distribution systems and customers insights, if well harnessed, could leapfrog progress in addressing the food and nutrition crises. While business can do lots more, its combined impact will be minimal if a range of essential government actions and policies are not addressed. Governments need to create innovative and complementary opportunities that include incentives for businesses including: setting clear nutritional guidelines for fortification and for ready-to eat products; offering agreements to endorse approved products and support their distribution to clinics and schools; eliminating duties on imported vitamins and other micronutrients; and providing tax and other incentives for industry to invest with donors in essential nutrition

  15. The role of business in addressing the long-term implications of the current food crisis.

    PubMed

    Yach, Derek

    2008-01-01

    Before the onset of the current food crisis, the evidence of a severely neglected nutrition crisis was starting to receive attention. Increased food prices are having severe impacts on the nutritional status of populations. Our current food system has evolved over decades in a largely unplanned manner and without consideration for the complexity and implications of linkages between health, nutrition, agricultural, economic, trade and security issues. The underlying causes for the nutrition crisis include the above, as well as decades of neglect with regard to nutrition, and agricultural science (especially in emerging markets); a failure of governance with respect to the major players involved in nutrition, a weak response by government donors and Foundations to invest in basic nutrition (in contrast to growing support for humanitarian aspects of food aid), and a reluctance to develop private-public partnerships. The emergence of new business models that tackle social problems while remaining profitable offers promise that the long term nutrition needs of people can be met. Businesses can have greater impact acting collectively than individually. Food, retail, food service, chemical and pharmaceutical companies have expertise, distribution systems and customers insights, if well harnessed, could leapfrog progress in addressing the food and nutrition crises. While business can do lots more, its combined impact will be minimal if a range of essential government actions and policies are not addressed. Governments need to create innovative and complementary opportunities that include incentives for businesses including: setting clear nutritional guidelines for fortification and for ready-to eat products; offering agreements to endorse approved products and support their distribution to clinics and schools; eliminating duties on imported vitamins and other micronutrients; and providing tax and other incentives for industry to invest with donors in essential nutrition

  16. Left ventricular partitioning in systolic heart failure subjects: addressing a mechanistic void with current therapies.

    PubMed

    Schäfer, Ulrich

    2016-05-17

    ICD patients with narrow QRS, CRT non-responders, and functional MR patients all have one mechanistic failure mode that is left untreated - the scar left behind following an MI. ICDs, CRTs, and MitraClip implantation are all well-proven therapies, but the Parachute device may address the mechanistic void that remains after each of these therapies has been used and may further improve patients' outcomes. A pooled analysis of 134 subjects was conducted using the first three clinical trials which included subjects with symptomatic ischaemic HF with LV wall motion abnormalities secondary to MI, and an LV ejection fraction less than 40%. The two-year cumulative mortality rate was 12.9%, with 8.7% in the first year and an increment of 4.2% in the second, which is a 53% reduction as compared to the first year. There is a significant proportion of patients with ischaemic heart failure being excluded from cardiac rhythm management (CRT, etc.), leaving a large treatment gap until mechanical support devices (LVAD) or heart transplantation in progressive heart failure are indicated. Along with other heart failure devices, Parachute may be a useful treatment modality, addressing a mechanistic void in the treatment of this disease. Current data support improvements in haemodynamics, functional capacity, six-minute walk distance, quality of life and a promising decline in mortality two years after Parachute implantation. PMID:27174122

  17. High voltage fault current limiter having immersed phase coils

    DOEpatents

    Darmann, Francis Anthony

    2014-04-22

    A fault current limiter including: a ferromagnetic circuit formed from a ferromagnetic material and including at least a first limb, and a second limb; a saturation mechanism surrounding a limb for magnetically saturating the ferromagnetic material; a phase coil wound around a second limb; a dielectric fluid surrounding the phase coil; a gaseous atmosphere surrounding the saturation mechanism.

  18. The Current Limits for Radionuclides in Food in Japan.

    PubMed

    Iwaoka, Kazuki

    2016-11-01

    After the TEPCO Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, the current limits in Japan on the radionuclide contamination of food [100 Bq kg for general foods, 50 Bq kg for milk and infant foods, and 10 Bq kg for drinking water as radioactive cesium (Cs + Cs)] were established on the basis of an effective dose of 1 mSv y, consistent with international standards to mitigate the exposure of the general public to radiation. Measures that include recalling or restriction of food have been taken in cases when these limits were violated. As a result of these efforts, the actual effective doses of radioactive cesium (Cs + Cs) in foods approximately 1 y after the FDNPP accident were below 0.01 mSv y. However, there is little information on the current status of these limits in the literature, which necessitates a comprehensive review of the information that exists. In this paper, the concept behind the introduction of these limits, the methods by which they were derived, and the results of monitoring food accordingly, are reviewed. This information will be helpful in the case of a future accident, and it will also help to enhance the understanding of the current limits and to relieve the anxieties of the general public concerning radiation exposure from radionuclides in food.

  19. The Current Limits for Radionuclides in Food in Japan.

    PubMed

    Iwaoka, Kazuki

    2016-11-01

    After the TEPCO Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, the current limits in Japan on the radionuclide contamination of food [100 Bq kg for general foods, 50 Bq kg for milk and infant foods, and 10 Bq kg for drinking water as radioactive cesium (Cs + Cs)] were established on the basis of an effective dose of 1 mSv y, consistent with international standards to mitigate the exposure of the general public to radiation. Measures that include recalling or restriction of food have been taken in cases when these limits were violated. As a result of these efforts, the actual effective doses of radioactive cesium (Cs + Cs) in foods approximately 1 y after the FDNPP accident were below 0.01 mSv y. However, there is little information on the current status of these limits in the literature, which necessitates a comprehensive review of the information that exists. In this paper, the concept behind the introduction of these limits, the methods by which they were derived, and the results of monitoring food accordingly, are reviewed. This information will be helpful in the case of a future accident, and it will also help to enhance the understanding of the current limits and to relieve the anxieties of the general public concerning radiation exposure from radionuclides in food. PMID:27682906

  20. Indirectly sensing accelerator beam currents for limiting maximum beam current magnitude

    DOEpatents

    Bogaty, John M.; Clifft, Benny E.; Bollinger, Lowell M.

    1995-01-01

    A beam current limiter for sensing and limiting the beam current in a particle accelerator, such as a cyclotron or linear accelerator, used in scientific research and medical treatment. A pair of independently operable capacitive electrodes sense the passage of charged particle bunches to develop an RF signal indicative of the beam current magnitude produced at the output of a bunched beam accelerator. The RF signal produced by each sensing electrode is converted to a variable DC voltage indicative of the beam current magnitude. The variable DC voltages thus developed are compared to each other to verify proper system function and are further compared to known references to detect beam currents in excess of pre-established limits. In the event of a system malfunction, or if the detected beam current exceeds pre-established limits, the beam current limiter automatically inhibits further accelerator operation. A high Q tank circuit associated with each sensing electrode provides a narrow system bandwidth to reduce noise and enhance dynamic range. System linearity is provided by injecting, into each sensing electrode, an RF signal that is offset from the bunching frequency by a pre-determined beat frequency to ensure that subsequent rectifying diodes operate in a linear response region. The system thus provides a large dynamic range in combination with good linearity.

  1. Indirectly sensing accelerator beam currents for limiting maximum beam current magnitude

    DOEpatents

    Bogaty, J.M.; Clifft, B.E.; Bollinger, L.M.

    1995-08-08

    A beam current limiter is disclosed for sensing and limiting the beam current in a particle accelerator, such as a cyclotron or linear accelerator, used in scientific research and medical treatment. A pair of independently operable capacitive electrodes sense the passage of charged particle bunches to develop an RF signal indicative of the beam current magnitude produced at the output of a bunched beam accelerator. The RF signal produced by each sensing electrode is converted to a variable DC voltage indicative of the beam current magnitude. The variable DC voltages thus developed are compared to each other to verify proper system function and are further compared to known references to detect beam currents in excess of pre-established limits. In the event of a system malfunction, or if the detected beam current exceeds pre-established limits, the beam current limiter automatically inhibits further accelerator operation. A high Q tank circuit associated with each sensing electrode provides a narrow system bandwidth to reduce noise and enhance dynamic range. System linearity is provided by injecting, into each sensing electrode, an RF signal that is offset from the bunching frequency by a pre-determined beat frequency to ensure that subsequent rectifying diodes operate in a linear response region. The system thus provides a large dynamic range in combination with good linearity. 6 figs.

  2. TFCX current density and nuclear heating limitations for superconducting tokamaks

    SciTech Connect

    Kalsi, S.S.

    1985-01-01

    A major goal of the Tokamak Fusion Core Experiment (TFCX) study was to minimize the size of the device and achieve lowest cost. Two key factors influencing the size of the device employing superconducting magnets are toroidal field (TF) winding current density and its nuclear heat load withstand capability. Lower winding current density requires larger radial build of the winding pack. Likewise, lower allowable nuclear heating in the winding requires larger shield thickness between the plasma and coil. To achieve a low-cost device, it is essential to maximize the winding's current density and nuclear heating withstand capability. To meet this objective, the TFCX design specification adopted as goals a nominal winding current density of 3500 A/cm/sup 2/ with 10-T peak field at the winding, peak nuclear heat load limits of 1 mW/cm/sup 3/ for the nominal design and 50 mW/cm/sup 3/ for an advanced design. This study developed justification for these current density and nuclear heat load limits.

  3. Review of current technologies for urinary incontinence: strengths and limitations.

    PubMed

    Fader, M

    2003-01-01

    A wide range of continence products is available, and this paper focuses on products to prevent incontinence (such as urinals and commodes) and to contain or manage urinary incontinence (such as absorbent pads, penile sheaths and urethral catheters). Drawing on results from published clinical evaluations at the Continence Product Evaluation Network at UCL and at other centres, the strengths and limitations of the major categories of incontinence products currently on the market are reviewed. It is concluded that, although products for continence have improved considerably over the last 20 years, there is considerable scope for the designer and engineer to improve on current products. PMID:12885193

  4. Asymptotic current-voltage relations for currents exceeding the diffusion limit

    NASA Astrophysics Data System (ADS)

    Yariv, Ehud

    2009-11-01

    We consider the one-dimensional transport of ions into a perm-selective solid. Direct attempts to evaluate the current-voltage characteristics for currents exceeding the diffusion limit are frustrated by the appearance of nonconverging integrals. We describe how to overcome this obstacle using a regularization scheme.

  5. Limited Stage Follicular Lymphoma: Current Role of Radiation Therapy.

    PubMed

    Filippi, Andrea Riccardo; Ciammella, Patrizia; Ricardi, Umberto

    2016-01-01

    Radiation therapy (RT) alone has been considered for a long time as the standard therapeutic option for limited stage FL, due to its high efficacy in terms of local disease control with a quite significant proportion of "cured" patients (without further relapses at 10-15 years). Multiple therapeutic choices are currently accepted for the management of early stage FL at diagnosis, and better staging procedures as well as better systemic therapy partially modified the role of RT in this setting. RT has also changed in terms of prescribed dose as well as treatment volumes. In this review, we present and discuss the current role of RT for limited stage FL in light of the historical data and the modern RT concepts along with the possible combination with systemic therapy. PMID:27648204

  6. Limited Stage Follicular Lymphoma: Current Role of Radiation Therapy

    PubMed Central

    Filippi, Andrea Riccardo; Ciammella, Patrizia; Ricardi, Umberto

    2016-01-01

    Radiation therapy (RT) alone has been considered for a long time as the standard therapeutic option for limited stage FL, due to its high efficacy in terms of local disease control with a quite significant proportion of “cured” patients (without further relapses at 10–15 years). Multiple therapeutic choices are currently accepted for the management of early stage FL at diagnosis, and better staging procedures as well as better systemic therapy partially modified the role of RT in this setting. RT has also changed in terms of prescribed dose as well as treatment volumes. In this review, we present and discuss the current role of RT for limited stage FL in light of the historical data and the modern RT concepts along with the possible combination with systemic therapy. PMID:27648204

  7. Limited Stage Follicular Lymphoma: Current Role of Radiation Therapy

    PubMed Central

    Filippi, Andrea Riccardo; Ciammella, Patrizia; Ricardi, Umberto

    2016-01-01

    Radiation therapy (RT) alone has been considered for a long time as the standard therapeutic option for limited stage FL, due to its high efficacy in terms of local disease control with a quite significant proportion of “cured” patients (without further relapses at 10–15 years). Multiple therapeutic choices are currently accepted for the management of early stage FL at diagnosis, and better staging procedures as well as better systemic therapy partially modified the role of RT in this setting. RT has also changed in terms of prescribed dose as well as treatment volumes. In this review, we present and discuss the current role of RT for limited stage FL in light of the historical data and the modern RT concepts along with the possible combination with systemic therapy.

  8. Distribution vacuum-arc fault-current limiter. Final report

    SciTech Connect

    Burrage, L.M.; Pedrow, P.D.; Veverka, E.F.; Landergott, D.R.; Driear, J.M.; Owens, W.R.; Nurmepuu, K.

    1982-02-01

    The objective of this project was the demonstration of the feasibility of using a vacuum arc as the basis for a distribution class fault current limiter. The concept used was an electric discharge in vacuum between a hollow cylindrical anode and a short rod cathode located on the axis of the anode. The device has two modes of operation. One mode utilizes an externally applied axial magnetic field; the other uses the discharge's inherent magnetic field. A series of experiments yielded analytic models of the two modes of operation. It was found that for both cases, high arc voltages were generated by the conduction of current through an electron space charge region (sheath) near the anode. It was concluded that the vacuum arc with applied axial magnetic field was the most suitable mode for use as a commutating switch for a switched resistor fault current limiter. The test device used for the project could reliably commutate currents of 6.4 kA peak. The design of a 20 kA peak prototype commutating switch was completed but the prototype was not constructed. This vacuum arc device with applied axial magnetic field may be considered an alternative switching device for dc applications.

  9. Superconducting fault current-limiter with variable shunt impedance

    SciTech Connect

    Llambes, Juan Carlos H; Xiong, Xuming

    2013-11-19

    A superconducting fault current-limiter is provided, including a superconducting element configured to resistively or inductively limit a fault current, and one or more variable-impedance shunts electrically coupled in parallel with the superconducting element. The variable-impedance shunt(s) is configured to present a first impedance during a superconducting state of the superconducting element and a second impedance during a normal resistive state of the superconducting element. The superconducting element transitions from the superconducting state to the normal resistive state responsive to the fault current, and responsive thereto, the variable-impedance shunt(s) transitions from the first to the second impedance. The second impedance of the variable-impedance shunt(s) is a lower impedance than the first impedance, which facilitates current flow through the variable-impedance shunt(s) during a recovery transition of the superconducting element from the normal resistive state to the superconducting state, and thus, facilitates recovery of the superconducting element under load.

  10. Negative Differential Conductance from Space Charge Limited Currents in Semiconductors

    NASA Astrophysics Data System (ADS)

    Brooks, Andrew; Zhang, Xiaoguang

    Applying the theory of space charge limited currents (SCLC), we show that negative differential conductance can arise from doubly occupied traps that are nearly degenerate with the bottom of the conduction band. Using degenerate state perturbation theory, the Coulomb energy of the doubly occupied traps is shown to depend on the hybridization with the conduction band states. Initially, when carriers are injected into the solid, traps begin to fill while the conduction band states stay relatively empty and thus accessible to trapped electrons via hopping. Trap and conduction states continue to be filled as current is increased, and the energy of trapped electrons begins to rise. A critical current is reached whereupon a further increase in current leads to a reduction of filled traps (i.e. a reduction of space charge in the solid), and thus a corresponding decrease in voltage. This trend in the current-voltage characteristic curves persists until the bottom of the conduction band has been filled, then voltage rises with current.

  11. Efforts to Empower Teachers in Ethiopia to Address Local Environmental Problems: Achievements and Limitations

    ERIC Educational Resources Information Center

    Dalelo, Aklilu

    2009-01-01

    It is believed that the possibilities of integrating environmental issues into the formal and nonformal education programs depend on the capacity of teachers who put such programs into effect. A pilot project, aimed at building the capacity of schools in Ethiopia to address key environmental issues, was initiated in 2004. Among the major…

  12. Addressing the limits to adaptation across four damage--response systems

    EPA Science Inventory

    Our ability to adapt to climate change is not boundless, and previous modeling shows that capacity limited adaptation will play a policy-significant role in future decisions about climate change. These limits are delineated by capacity thresholds, after which climate damages beg...

  13. Limitations for current production in Geobacter sulfurreducens biofilms.

    PubMed

    Bonanni, P Sebastian; Bradley, Dan F; Schrott, Germán D; Busalmen, Juan Pablo

    2013-04-01

    Devices that exploit electricity produced by electroactive bacteria such as Geobacter sulfurreducens have not yet been demonstrated beyond the laboratory scale. The current densities are far from the maximum that the bacteria can produce because fundamental properties such as the mechanism of extracellular electron transport and factors limiting cell respiration remain unclear. In this work, a strategy for the investigation of electroactive biofilms is presented. Numerical modeling of the response of G. sulfurreducens biofilms cultured on a rotating disk electrode has allowed for the discrimination of different limiting steps in the process of current production within a biofilm. The model outputs reveal that extracellular electron transport limits the respiration rate of the cells furthest from the electrode to the extent that cell division is not possible. The mathematical model also demonstrates that recent findings such as the existence of a redox gradient in actively respiring biofilms can be explained by an electron hopping mechanism but not when considering metallic-like conductivities. PMID:23417889

  14. Addressing Hydro-economic Modeling Limitations - A Limited Foresight Sacramento Valley Model and an Open-source Modeling Platform

    NASA Astrophysics Data System (ADS)

    Harou, J. J.; Hansen, K. M.

    2008-12-01

    Increased scarcity of world water resources is inevitable given the limited supply and increased human pressures. The idea that "some scarcity is optimal" must be accepted for rational resource use and infrastructure management decisions to be made. Hydro-economic systems models are unique at representing the overlap of economic drivers, socio-political forces and distributed water resource systems. They demonstrate the tangible benefits of cooperation and integrated flexible system management. Further improvement of models, quality control practices and software will be needed for these academic policy tools to become accepted into mainstream water resource practice. Promising features include: calibration methods, limited foresight optimization formulations, linked simulation-optimization approaches (e.g. embedding pre-existing calibrated simulation models), spatial groundwater models, stream-aquifer interactions and stream routing, etc.. Conventional user-friendly decision support systems helped spread simulation models on a massive scale. Hydro-economic models must also find a means to facilitate construction, distribution and use. Some of these issues and model features are illustrated with a hydro-economic optimization model of the Sacramento Valley. Carry-over storage value functions are used to limit hydrologic foresight of the multi- period optimization model. Pumping costs are included in the formulation by tracking regional piezometric head of groundwater sub-basins. To help build and maintain this type of network model, an open-source water management modeling software platform is described and initial project work is discussed. The objective is to generically facilitate the connection of models, such as those developed in a modeling environment (GAMS, MatLab, Octave, "), to a geographic user interface (drag and drop node-link network) and a database (topology, parameters and time series). These features aim to incrementally move hydro- economic models

  15. [Real-time multiplane echocardiography. Current applications, limits and perspectives].

    PubMed

    Mele, Donato; Galderisi, Maurizio; Badano, Luigi; Agricola, Eustachio; Nistri, Stefano; Sciomer, Susanna; Ballo, Piercarlo; Buralli, Simona; D'Andrea, Antonello; D'Errico, Arcangelo; Losi, Maria Angela; Mondillo, Sergio

    2010-12-01

    Echocardiography is the most commonly used imaging technique in current clinical cardiology practice and is usually performed using a monoplane approach. In recent years new matrix-array transducers have become available that allow the real-time simultaneous display of two or more echocardiographic scanning planes from the same acoustic window. This multiplane approach is particularly interesting as it may reduce, during the examination, the number of probe movements and consequently facilitate image acquisition. In some clinical applications, moreover, the multiplane approach improves both accuracy and reproducibility of echocardiography. This review evaluates the state of the art of multiplane echocardiography and discusses possible clinical applications, advantages and limitations of this technique.

  16. Space charge limited current emission for a sharp tip

    SciTech Connect

    Zhu, Y. B. Ang, L. K.

    2015-05-15

    In this paper, we formulate a self-consistent model to study the space charge limited current emission from a sharp tip in a dc gap. The tip is assumed to have a radius in the order of 10s nanometer. The electrons are emitted from the tip due to field emission process. It is found that the localized current density J at the apex of the tip can be much higher than the classical Child Langmuir law (flat surface). A scaling of J ∝ V{sub g}{sup 3/2}/D{sup m}, where V{sub g} is the gap bias, D is the gap size, and m = 1.1–1.2 (depending on the emission area or radius) is proposed. The effects of non-uniform emission and the spatial dependence of work function are presented.

  17. Short wavelength limits of current shot noise suppression

    SciTech Connect

    Nause, Ariel; Dyunin, Egor; Gover, Avraham

    2014-08-15

    Shot noise in electron beam was assumed to be one of the features beyond control of accelerator physics. Current results attained in experiments at Accelerator Test Facility in Brookhaven and Linac Coherent Light Source in Stanford suggest that the control of the shot noise in electron beam (and therefore of spontaneous radiation and Self Amplified Spontaneous Emission of Free Electron Lasers) is feasible at least in the visible range of the spectrum. Here, we present a general linear formulation for collective micro-dynamics of e-beam noise and its control. Specifically, we compare two schemes for current noise suppression: a quarter plasma wavelength drift section and a combined drift/dispersive (transverse magnetic field) section. We examine and compare their limits of applicability at short wavelengths via considerations of electron phase-spread and the related Landau damping effect.

  18. Theory of Space Charge Limited Current in Fractional Dimensional Space

    NASA Astrophysics Data System (ADS)

    Zubair, Muhammad; Ang, L. K.

    The concept of fractional dimensional space has been effectively applied in many areas of physics to describe the fractional effects on the physical systems. We will present some recent developments of space charge limited (SCL) current in free space and solid in the framework of fractional dimensional space which may account for the effect of imperfectness or roughness of the electrode surface. For SCL current in free space, the governing law is known as the Child-Langmuir (CL) law. Its analogy in a trap-free solid (or dielectric) is known as Mott-Gurney (MG) law. This work extends the one-dimensional CL Law and MG Law for the case of a D-dimensional fractional space with 0 < D <= 1 where parameter D defines the degree of roughness of the electrode surface. Such a fractional dimensional space generalization of SCL current theory can be used to characterize the charge injection by the imperfectness or roughness of the surface in applications related to high current cathode (CL law), and organic electronics (MG law). In terms of operating regime, the model has included the quantum effects when the spacing between the electrodes is small.

  19. Limits to Economic Growth: Why Direct Investments Are Needed to Address Child Undernutrition in India.

    PubMed

    Subramanian, S V; Subramanyam, Malavika A

    2015-11-01

    About two of every five undernourished young children of the world live in India. These high levels of child undernutrition have persisted in India for several years, even in its relatively well-developed states. Moreover, this pattern was observed during a period of rapid economic growth. Evidence from India and other developing countries suggests that economic growth has little to no impact on reducing child undernutrition. We argue that a growth-mediated strategy is unlikely to be effective in tackling child undernutrition unless growth is pro-poor and leads to investment in programs addressing the root causes of this persistent challenge.

  20. Limits to Economic Growth: Why Direct Investments Are Needed to Address Child Undernutrition in India

    PubMed Central

    Subramanyam, Malavika A

    2015-01-01

    About two of every five undernourished young children of the world live in India. These high levels of child undernutrition have persisted in India for several years, even in its relatively well-developed states. Moreover, this pattern was observed during a period of rapid economic growth. Evidence from India and other developing countries suggests that economic growth has little to no impact on reducing child undernutrition. We argue that a growth-mediated strategy is unlikely to be effective in tackling child undernutrition unless growth is pro-poor and leads to investment in programs addressing the root causes of this persistent challenge. PMID:26617445

  1. Addressing Therapeutic Options for Ebola Virus Infection in Current and Future Outbreaks

    PubMed Central

    Hober, Didier; Blondiaux, Joel

    2015-01-01

    Ebola virus can cause severe hemorrhagic disease with high fatality rates. Currently, no specific therapeutic agent or vaccine has been approved for treatment and prevention of Ebola virus infection of humans. Although the number of Ebola cases has fallen in the last few weeks, multiple outbreaks of Ebola virus infection and the likelihood of future exposure highlight the need for development and rapid evaluation of pre- and postexposure treatments. Here, we briefly review the existing and future options for anti-Ebola therapy, based on the data coming from rare clinical reports, studies on animals, and results from in vitro models. We also project the mechanistic hypotheses of several potential drugs against Ebola virus, including small-molecule-based drugs, which are under development and being tested in animal models or in vitro using various cell types. Our paper discusses strategies toward identifying and testing anti-Ebola virus properties of known and medically approved drugs, especially those that can limit the pathological inflammatory response in Ebola patients and thereby provide protection from mortality. We underline the importance of developing combinational therapy for better treatment outcomes for Ebola patients. PMID:26248374

  2. Addressing Therapeutic Options for Ebola Virus Infection in Current and Future Outbreaks.

    PubMed

    Haque, Azizul; Hober, Didier; Blondiaux, Joel

    2015-10-01

    Ebola virus can cause severe hemorrhagic disease with high fatality rates. Currently, no specific therapeutic agent or vaccine has been approved for treatment and prevention of Ebola virus infection of humans. Although the number of Ebola cases has fallen in the last few weeks, multiple outbreaks of Ebola virus infection and the likelihood of future exposure highlight the need for development and rapid evaluation of pre- and postexposure treatments. Here, we briefly review the existing and future options for anti-Ebola therapy, based on the data coming from rare clinical reports, studies on animals, and results from in vitro models. We also project the mechanistic hypotheses of several potential drugs against Ebola virus, including small-molecule-based drugs, which are under development and being tested in animal models or in vitro using various cell types. Our paper discusses strategies toward identifying and testing anti-Ebola virus properties of known and medically approved drugs, especially those that can limit the pathological inflammatory response in Ebola patients and thereby provide protection from mortality. We underline the importance of developing combinational therapy for better treatment outcomes for Ebola patients.

  3. The GÉANT network: addressing current and future needs of the HEP community

    NASA Astrophysics Data System (ADS)

    Capone, Vincenzo; Usman, Mian

    2015-12-01

    The GÉANT infrastructure is the backbone that serves the scientific communities in Europe for their data movement needs and their access to international research and education networks. Using the extensive fibre footprint and infrastructure in Europe the GÉANT network delivers a portfolio of services aimed to best fit the specific needs of the users, including Authentication and Authorization Infrastructure, end-to-end performance monitoring, advanced network services (dynamic circuits, L2-L3VPN, MD-VPN). This talk will outline the factors that help the GÉANT network to respond to the needs of the High Energy Physics community, both in Europe and worldwide. The Pan-European network provides the connectivity between 40 European national research and education networks. In addition, GÉANT also connects the European NRENs to the R&E networks in other world region and has reach to over 110 NREN worldwide, making GÉANT the best connected Research and Education network, with its multiple intercontinental links to different continents e.g. North and South America, Africa and Asia-Pacific. The High Energy Physics computational needs have always had (and will keep having) a leading role among the scientific user groups of the GÉANT network: the LHCONE overlay network has been built, in collaboration with the other big world REN, specifically to address the peculiar needs of the LHC data movement. Recently, as a result of a series of coordinated efforts, the LHCONE network has been expanded to the Asia-Pacific area, and is going to include some of the main regional R&E network in the area. The LHC community is not the only one that is actively using a distributed computing model (hence the need for a high-performance network); new communities are arising, as BELLE II. GÉANT is deeply involved also with the BELLE II Experiment, to provide full support to their distributed computing model, along with a perfSONAR-based network monitoring system. GÉANT has also

  4. Ion current rectification, limiting and overlimiting conductances in nanopores.

    PubMed

    van Oeffelen, Liesbeth; Van Roy, Willem; Idrissi, Hosni; Charlier, Daniel; Lagae, Liesbet; Borghs, Gustaaf

    2015-01-01

    Previous reports on Poisson-Nernst-Planck (PNP) simulations of solid-state nanopores have focused on steady state behaviour under simplified boundary conditions. These are Neumann boundary conditions for the voltage at the pore walls, and in some cases also Donnan equilibrium boundary conditions for concentrations and voltages at both entrances of the nanopore. In this paper, we report time-dependent and steady state PNP simulations under less restrictive boundary conditions, including Neumann boundary conditions applied throughout the membrane relatively far away from the nanopore. We simulated ion currents through cylindrical and conical nanopores with several surface charge configurations, studying the spatial and temporal dependence of the currents contributed by each ion species. This revealed that, due to slow co-diffusion of oppositely charged ions, steady state is generally not reached in simulations or in practice. Furthermore, it is shown that ion concentration polarization is responsible for the observed limiting conductances and ion current rectification in nanopores with asymmetric surface charges or shapes. Hence, after more than a decade of collective research attempting to understand the nature of ion current rectification in solid-state nanopores, a relatively intuitive model is retrieved. Moreover, we measured and simulated current-voltage characteristics of rectifying silicon nitride nanopores presenting overlimiting conductances. The similarity between measurement and simulation shows that overlimiting conductances can result from the increased conductance of the electric double-layer at the membrane surface at the depletion side due to voltage-induced polarization charges. The MATLAB source code of the simulation software is available via the website http://micr.vub.ac.be. PMID:25978328

  5. Ion Current Rectification, Limiting and Overlimiting Conductances in Nanopores

    PubMed Central

    van Oeffelen, Liesbeth; Van Roy, Willem; Idrissi, Hosni; Charlier, Daniel; Lagae, Liesbet; Borghs, Gustaaf

    2015-01-01

    Previous reports on Poisson-Nernst-Planck (PNP) simulations of solid-state nanopores have focused on steady state behaviour under simplified boundary conditions. These are Neumann boundary conditions for the voltage at the pore walls, and in some cases also Donnan equilibrium boundary conditions for concentrations and voltages at both entrances of the nanopore. In this paper, we report time-dependent and steady state PNP simulations under less restrictive boundary conditions, including Neumann boundary conditions applied throughout the membrane relatively far away from the nanopore. We simulated ion currents through cylindrical and conical nanopores with several surface charge configurations, studying the spatial and temporal dependence of the currents contributed by each ion species. This revealed that, due to slow co-diffusion of oppositely charged ions, steady state is generally not reached in simulations or in practice. Furthermore, it is shown that ion concentration polarization is responsible for the observed limiting conductances and ion current rectification in nanopores with asymmetric surface charges or shapes. Hence, after more than a decade of collective research attempting to understand the nature of ion current rectification in solid-state nanopores, a relatively intuitive model is retrieved. Moreover, we measured and simulated current-voltage characteristics of rectifying silicon nitride nanopores presenting overlimiting conductances. The similarity between measurement and simulation shows that overlimiting conductances can result from the increased conductance of the electric double-layer at the membrane surface at the depletion side due to voltage-induced polarization charges. The MATLAB source code of the simulation software is available via the website http://micr.vub.ac.be. PMID:25978328

  6. Review article: Intrapartum neuraxial analgesia and breastfeeding outcomes: limitations of current knowledge.

    PubMed

    Szabo, Ashley L

    2013-02-01

    Although numerous studies have addressed the relationship between intrapartum neuraxial analgesia, particularly epidural fentanyl, and breastfeeding, substantial study design limitations have precluded the current literature from furnishing strong, clinically significant conclusions. Lack of randomized controlled trials, nonstandardization of breastfeeding evaluations across studies, and failure to control for confounding variables all pose significant problems. Further research is needed to elucidate the specific relationship between neuraxial opioids and breastfeeding and, if there are significant associations, whether these drugs act directly on neonatal brain tissue to attenuate exhibition of breastfeeding behaviors. In this review, I will detail the deficiencies of the current literature and make recommendations for future research. PMID:23302971

  7. Disaster response and people experiencing homelessness: Addressing challenges of a population with limited resources.

    PubMed

    Wexler, Bryan; Smith, Mary-Elise

    2015-01-01

    In this article the authors provide an overview of some issues that inhibit disaster planning and response for people experiencing homelessness and discuss the planning process conducted for this population in Worcester, MA. People experiencing homelessness face numerous challenges in preparing for disasters both natural and human caused. Similarly, providers attempting to aid these individuals must recognize and overcome various factors that hamper efforts to provide assistance. People experiencing homelessness lack the general resources many in the United States take for granted, including food, shelter, communication methods, and transportation. The population also has an increased prevalence of medical and psychiatric conditions. These factors amplify the typical difficulties in preparedness, communication, sheltering, and training for disasters. With these principles in mind, the authors reviewed the literature for best practices, identified potential stakeholders, and developed an annex to help address organization and delivery of care to those experiencing homelessness during a disaster. PMID:26150363

  8. The Importance of Exposure in Addressing Current and Emerging Air Quality Issues

    EPA Science Inventory

    The air quality issues that we face today and will face in the future are becoming increasingly more complex and require an improved understanding of human exposure to be effectively addressed. The objectives of this paper are (1) to discuss how concepts of human exposure and ex...

  9. A Problem-Solving Approach to Addressing Current Global Challenges in Education

    ERIC Educational Resources Information Center

    Chapman, Judith D.; Aspin, David N.

    2013-01-01

    This paper begins with an analysis of global problems shaping education, particularly as they impact upon learning and life chances. In addressing these problems a range of philosophical positions and controversies are considered, including: traditional romantic and institutional views of schooling; and more recent maximalist, neo-liberal,…

  10. Limit on Tensor Currents from ^{8}Li β Decay.

    PubMed

    Sternberg, M G; Segel, R; Scielzo, N D; Savard, G; Clark, J A; Bertone, P F; Buchinger, F; Burkey, M; Caldwell, S; Chaudhuri, A; Crawford, J E; Deibel, C M; Greene, J; Gulick, S; Lascar, D; Levand, A F; Li, G; Pérez Galván, A; Sharma, K S; Van Schelt, J; Yee, R M; Zabransky, B J

    2015-10-30

    In the standard model, the weak interaction is formulated with a purely vector-axial-vector (V-A) structure. Without restriction on the chirality of the neutrino, the most general limits on tensor currents from nuclear β decay are dominated by a single measurement of the β-ν[over ¯] correlation in ^{6}He β decay dating back over a half century. In the present work, the β-ν[over ¯]-α correlation in the β decay of ^{8}Li and subsequent α-particle breakup of the ^{8}Be^{*} daughter was measured. The results are consistent with a purely V-A interaction and in the case of couplings to right-handed neutrinos (C_{T}=-C_{T}^{'}) limits the tensor fraction to |C_{T}/C_{A}|^{2}<0.011 (95.5% C.L.). The measurement confirms the ^{6}He result using a different nuclear system and employing modern ion-trapping techniques subject to different systematic uncertainties. PMID:26565463

  11. Limit on Tensor Currents from ^{8}Li β Decay.

    PubMed

    Sternberg, M G; Segel, R; Scielzo, N D; Savard, G; Clark, J A; Bertone, P F; Buchinger, F; Burkey, M; Caldwell, S; Chaudhuri, A; Crawford, J E; Deibel, C M; Greene, J; Gulick, S; Lascar, D; Levand, A F; Li, G; Pérez Galván, A; Sharma, K S; Van Schelt, J; Yee, R M; Zabransky, B J

    2015-10-30

    In the standard model, the weak interaction is formulated with a purely vector-axial-vector (V-A) structure. Without restriction on the chirality of the neutrino, the most general limits on tensor currents from nuclear β decay are dominated by a single measurement of the β-ν[over ¯] correlation in ^{6}He β decay dating back over a half century. In the present work, the β-ν[over ¯]-α correlation in the β decay of ^{8}Li and subsequent α-particle breakup of the ^{8}Be^{*} daughter was measured. The results are consistent with a purely V-A interaction and in the case of couplings to right-handed neutrinos (C_{T}=-C_{T}^{'}) limits the tensor fraction to |C_{T}/C_{A}|^{2}<0.011 (95.5% C.L.). The measurement confirms the ^{6}He result using a different nuclear system and employing modern ion-trapping techniques subject to different systematic uncertainties.

  12. Superconducting matrix fault current limiter with current-driven trigger mechanism

    DOEpatents

    Yuan, Xing

    2008-04-15

    A modular and scalable Matrix-type Fault Current Limiter (MFCL) that functions as a "variable impedance" device in an electric power network, using components made of superconducting and non-superconducting electrically conductive materials. An inductor is connected in series with the trigger superconductor in the trigger matrix and physically surrounds the superconductor. The current surge during a fault will generate a trigger magnetic field in the series inductor to cause fast and uniform quenching of the trigger superconductor to significantly reduce burnout risk due to superconductor material non-uniformity.

  13. 78 FR 45910 - Proposed Information Collection; Comment Request; Current Population Survey (CPS) Email Address...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE Census Bureau Proposed Information Collection; Comment Request; Current Population Survey (CPS) Email... Population Survey (CPS) has been collecting data on household employment for decades. Through the years,...

  14. Comparative outcome evaluations of psychotherapies: Guidelines for addressing eight limitations of the gold standard of causal inference.

    PubMed

    Staines, Graham L

    2007-06-01

    Although randomized experiments represent the gold standard in causal research, their limitations are easily overlooked, especially in field experiments. Although discussions of the limitations of field experiments typically detail problems of design implementation, field experiments have limitations even if their randomized designs are successfully implemented. This is particularly true of comparative evaluations of psychotherapy programs. Accordingly, this article focuses on eight limitations that pervade such comparative treatment research: (a) Direct and indirect effects are conflated; (b) the investigation of interactions is limited; (c) attention is diverted from background conditions; (d) temporal factors complicate causal inferences; (e) the stable-unit-treatment-value assumption is easily violated; (f) therapist effects can confound therapy method effects; (g) differential effects of treatment methods are small; and (h) generalizability of treatment research findings is indeterminate. In addition to explaining each limitation, the author proposes research strategies for addressing it. The author concludes that attention to these 8 limitations and to the various strategies for overcoming them can increase increase the causal contribution of experimental evaluations of psychotherapies. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

  15. Current limitations and challenges in nanowaste detection, characterisation and monitoring

    SciTech Connect

    Part, Florian; Zecha, Gudrun; Causon, Tim; Sinner, Eva-Kathrin

    2015-09-15

    Highlights: • First review on detection of nanomaterials in complex waste samples. • Focus on nanoparticles in solid, liquid and gaseous waste samples. • Summary of current applicable methods for nanowaste detection and characterisation. • Limitations and challenges of characterisation of nanoparticles in waste. - Abstract: Engineered nanomaterials (ENMs) are already extensively used in diverse consumer products. Along the life cycle of a nano-enabled product, ENMs can be released and subsequently accumulate in the environment. Material flow models also indicate that a variety of ENMs may accumulate in waste streams. Therefore, a new type of waste, so-called nanowaste, is generated when end-of-life ENMs and nano-enabled products are disposed of. In terms of the precautionary principle, environmental monitoring of end-of-life ENMs is crucial to allow assessment of the potential impact of nanowaste on our ecosystem. Trace analysis and quantification of nanoparticulate species is very challenging because of the variety of ENM types that are used in products and low concentrations of nanowaste expected in complex environmental media. In the framework of this paper, challenges in nanowaste characterisation and appropriate analytical techniques which can be applied to nanowaste analysis are summarised. Recent case studies focussing on the characterisation of ENMs in waste streams are discussed. Most studies aim to investigate the fate of nanowaste during incineration, particularly considering aerosol measurements; whereas, detailed studies focusing on the potential release of nanowaste during waste recycling processes are currently not available. In terms of suitable analytical methods, separation techniques coupled to spectrometry-based methods are promising tools to detect nanowaste and determine particle size distribution in liquid waste samples. Standardised leaching protocols can be applied to generate soluble fractions stemming from solid wastes, while

  16. Approaches to overcome current limitations of HIFU treatment

    NASA Astrophysics Data System (ADS)

    Umemura, Shin-Ichiro; Kawabata, Ken-Ichi; Sasaki, Kazuaki; Azuma, Takashi; Ishida, Kazunari; Kubota, Jun; Ichihara, Mitsuyoshi; Okai, Takashi

    2001-05-01

    Noninvasive therapy with HIFU has been successfully applied to transrectal treatment of prostate cancer as well as benign prostate hyperplasia. However, there are two major technical reasons why its clinical application to other organs is currently limited: (1) low throughput of treatment and (2) lack of penetration to deep tissues. To multiply the throughput, a split-focus technique, in which the focal spot is enlarged primarily in the lateral direction, was developed. An electronically variable focus array transducer was also developed to enhance the throughput. An approach to treat a large volume of uterus myoma by coagulating its feeding arteries has been studied. The tissue volume to be coagulated can be thereby reduced by orders of magnitude. The penetration and throughput can potentially be improved at the same time by delivering a microbubble agent to the target tissue. It was theoretically predicted that a microbubble agent could multiply the ultrasonic tissue absorption. The effectiveness of this approach was confirmed in animal experiments using Optison. Real-time monitoring of tissue coagulation during HIFU exposure also can enhance the throughput through preventing excess deposition of ultrasonic energy. Monitoring coagulation by imaging local displacement in tissue with ultrasound will be discussed as well.

  17. Beyond the current noise limit in imaging through turbulent medium.

    PubMed

    Popowicz, Adam; Kurek, Aleksander; Pollo, Agnieszka; Smolka, Bogdan

    2015-05-15

    Shift-and-add is an approach employed to mitigate the phenomenon of resolution degradation in images acquired through a turbulent medium. Using this technique, a large number of consecutive short exposures is registered below the coherence time of the atmosphere or other blurring medium. The acquired images are shifted to the position of the brightest speckle and stacked together to obtain high resolution and high signal-to-noise frame. In this Letter, we present a highly efficient method for determination of frame shifts, even if in a single frame the object cannot be distinguished from the background noise. The technique utilizes our custom genetic algorithm, which iteratively evolves a set of image shifts. We used the maximal energy of stacked images as an objective function for shifts estimation and validate the efficiency of the method on simulated and real images of simple and complex sources. Obtained results confirmed that our proposed method allows for the recovery of spatial distribution of objects even only 2% brighter than their background. The presented approach extends significantly current limits of image reconstruction with the use of shift-and-add method. The applications of our algorithm include both the optical and the infrared imaging. Our method may be also employed as a digital image stabilizer in extremely low light level conditions in professional and consumer applications. PMID:26393694

  18. Multiscale Modeling in Computational Biomechanics: Determining Computational Priorities and Addressing Current Challenges

    SciTech Connect

    Tawhai, Merryn; Bischoff, Jeff; Einstein, Daniel R.; Erdemir, Ahmet; Guess, Trent; Reinbolt, Jeff

    2009-05-01

    Abstract In this article, we describe some current multiscale modeling issues in computational biomechanics from the perspective of the musculoskeletal and respiratory systems and mechanotransduction. First, we outline the necessity of multiscale simulations in these biological systems. Then we summarize challenges inherent to multiscale biomechanics modeling, regardless of the subdiscipline, followed by computational challenges that are system-specific. We discuss some of the current tools that have been utilized to aid research in multiscale mechanics simulations, and the priorities to further the field of multiscale biomechanics computation.

  19. Addressing neuropsychiatric disturbances during rehabilitation after traumatic brain injury: current and future methods

    PubMed Central

    Arciniegas, David B.

    2011-01-01

    Cognitive, emotional, behavioral, and sensorimotor disturbances are the principal clinical manifestations of traumatic brain injury (TBI) throughout the early postinjury period. These post-traumatic neuropsychiatric disturbances present substantial challenges to patients, their families, and clinicians providing their rehabilitative care, the optimal approaches to which remain incompletely developed. In this article, a neuropsychiairically informed, neurobiologically anchored approach to understanding and meeting challenges is described. The foundation for thai approach is laid, with a review of clinical case definitions of TBI and clarification of their intended referents. The differential diagnosis of event-related neuropsychiatric disturbances is considered next, after which the clinical and neurobiological heterogeneity within the diagnostic category of TBI are discussed. The clinical manifestations of biomechanical force-induced brain dysfunction are described as a state of post-traumatic encephalopathy (PTE) comprising several phenomenologically distinct stages, PTE is then used as a framework for understanding and clinically evaluating the neuropsychiatric sequelae of TBI encountered commonly during the early post-injury rehabilitation period, and for considering the types and timings of neurorehabilitative interventions. Finally, directions for future research that may address productively the challenges to TBI rehabilitation presented by neuropsychiatric disturbances are considered. PMID:22034400

  20. Addressing Childhood Cancer in Low-Resource Countries: Current Challenges, Strategies, and Recommendations.

    PubMed

    Mbah Afungchwi, Glenn; Challinor, Julia

    2016-07-01

    Children and adolescents represent a small, but critically important, number of patients with cancer worldwide (14.1 million newly diagnosed adults versus 160,000 children annually). The life years saved when a child is cured of cancer are about 71 compared to 15 years for an adult in most high-income countries (HICs). In HICs, about 80% of children survive cancer. Unfortunately, in low- and middle-income countries (LMICs), the survival rates are generally 50% or less. In these resource-limited settings, only 15%-37% of children and adolescents have access to cancer treatment, and most are diagnosed with advanced-stage disease, making cure impossible. PMID:27314196

  1. Developing and Using Benchmarks for Eddy Current Simulation Codes Validation to Address Industrial Issues

    NASA Astrophysics Data System (ADS)

    Mayos, M.; Buvat, F.; Costan, V.; Moreau, O.; Gilles-Pascaud, C.; Reboud, C.; Foucher, F.

    2011-06-01

    To achieve performance demonstration, which is a legal requirement for the qualification of NDE processes applied on French nuclear power plants, the use of modeling tools is a valuable support, provided that the employed models have been previously validated. To achieve this, in particular for eddy current modeling, a validation methodology based on the use of specific benchmarks close to the actual industrial issue has to be defined. Nonetheless, considering the high variability in code origin and complexity, the feedback from experience on actual cases has shown that it was critical to define simpler generic and public benchmarks in order to perform a preliminary selection. A specific Working Group has been launched in the frame of COFREND, the French Association for NDE, resulting in the definition of several benchmark problems. This action is now ready for mutualization with similar international approaches.

  2. Single-site addressing of ultracold atoms beyond the diffraction limit via position-dependent adiabatic passage

    NASA Astrophysics Data System (ADS)

    Viscor, D.; Rubio, J. L.; Birkl, G.; Mompart, J.; Ahufinger, V.

    2012-12-01

    We propose a single-site addressing implementation based on the subwavelength localization via adiabatic passage (SLAP) technique. We consider a sample of ultracold neutral atoms loaded into a two-dimensional optical lattice with one atom per site. Each atom is modeled by a three-level Λ system in interaction with a pump and a Stokes laser pulse. Using a pump field with a node in its spatial profile, the atoms at all sites are transferred from one ground state of the system to the other via stimulated Raman adiabatic passage, except the one at the position of the node that remains in the initial ground state. This technique allows for the preparation, manipulation, and detection of atoms with a spatial resolution better than the diffraction limit, which either relaxes the requirements on the optical setup used or extends the achievable spatial resolution to lattice spacings smaller than accessible to date. In comparison to techniques based on coherent population trapping, SLAP gives a higher addressing resolution and has additional advantages such as robustness against parameter variations, coherence of the transfer process, and the absence of photon induced recoil. Additionally, the advantages of our proposal with respect to adiabatic spin-flip techniques are highlighted. Analytic expressions for the achievable addressing resolution and efficiency are derived and compared to numerical simulations for 87Rb atoms in state-of-the-art optical lattices.

  3. Potential of old-generation antibiotics to address current need for new antibiotics.

    PubMed

    Falagas, Matthew E; Grammatikos, Alexandros P; Michalopoulos, Argyris

    2008-10-01

    Despite the constantly increasing need for new antimicrobial agents, antibiotic drug discovery and development seem to have greatly decelerated in recent years. Presented with the significant problem of advancing antimicrobial resistance, the global scientific community has attempted to find alternative solutions; one of the most promising ones is the evaluation and use of old antibiotic compounds. Due to the low-level use of many of the old antibiotic compounds, these have remained active against a large number of currently prevalent bacterial isolates. Thus, clinicians are beginning to re-evaluate their use in various patient populations and infections, despite the fact that they were previously thought to be less effective and/or more toxic than newer agents. A number of old antibiotic compounds, such as polymyxins, fosfomycin, fusidic acid, cotrimoxazole, aminoglycosides and chloramphenicol, are re-emerging as valuable alternatives for the treatment of difficult-to-treat infections. The availability of novel genetic and molecular modification methods provides hope that the toxicity and efficacy drawbacks presented by some of these agents can be surpassed in the future. PMID:18847400

  4. Potential of old-generation antibiotics to address current need for new antibiotics.

    PubMed

    Falagas, Matthew E; Grammatikos, Alexandros P; Michalopoulos, Argyris

    2008-10-01

    Despite the constantly increasing need for new antimicrobial agents, antibiotic drug discovery and development seem to have greatly decelerated in recent years. Presented with the significant problem of advancing antimicrobial resistance, the global scientific community has attempted to find alternative solutions; one of the most promising ones is the evaluation and use of old antibiotic compounds. Due to the low-level use of many of the old antibiotic compounds, these have remained active against a large number of currently prevalent bacterial isolates. Thus, clinicians are beginning to re-evaluate their use in various patient populations and infections, despite the fact that they were previously thought to be less effective and/or more toxic than newer agents. A number of old antibiotic compounds, such as polymyxins, fosfomycin, fusidic acid, cotrimoxazole, aminoglycosides and chloramphenicol, are re-emerging as valuable alternatives for the treatment of difficult-to-treat infections. The availability of novel genetic and molecular modification methods provides hope that the toxicity and efficacy drawbacks presented by some of these agents can be surpassed in the future.

  5. Addressing Current Criticism Regarding the Value of Self-Report Dietary Data.

    PubMed

    Subar, Amy F; Freedman, Laurence S; Tooze, Janet A; Kirkpatrick, Sharon I; Boushey, Carol; Neuhouser, Marian L; Thompson, Frances E; Potischman, Nancy; Guenther, Patricia M; Tarasuk, Valerie; Reedy, Jill; Krebs-Smith, Susan M

    2015-12-01

    Recent reports have asserted that, because of energy underreporting, dietary self-report data suffer from measurement error so great that findings that rely on them are of no value. This commentary considers the amassed evidence that shows that self-report dietary intake data can successfully be used to inform dietary guidance and public health policy. Topics discussed include what is known and what can be done about the measurement error inherent in data collected by using self-report dietary assessment instruments and the extent and magnitude of underreporting energy compared with other nutrients and food groups. Also discussed is the overall impact of energy underreporting on dietary surveillance and nutritional epidemiology. In conclusion, 7 specific recommendations for collecting, analyzing, and interpreting self-report dietary data are provided: (1) continue to collect self-report dietary intake data because they contain valuable, rich, and critical information about foods and beverages consumed by populations that can be used to inform nutrition policy and assess diet-disease associations; (2) do not use self-reported energy intake as a measure of true energy intake; (3) do use self-reported energy intake for energy adjustment of other self-reported dietary constituents to improve risk estimation in studies of diet-health associations; (4) acknowledge the limitations of self-report dietary data and analyze and interpret them appropriately; (5) design studies and conduct analyses that allow adjustment for measurement error; (6) design new epidemiologic studies to collect dietary data from both short-term (recalls or food records) and long-term (food-frequency questionnaires) instruments on the entire study population to allow for maximizing the strengths of each instrument; and (7) continue to develop, evaluate, and further expand methods of dietary assessment, including dietary biomarkers and methods using new technologies. PMID:26468491

  6. Addressing Current Criticism Regarding the Value of Self-Report Dietary Data.

    PubMed

    Subar, Amy F; Freedman, Laurence S; Tooze, Janet A; Kirkpatrick, Sharon I; Boushey, Carol; Neuhouser, Marian L; Thompson, Frances E; Potischman, Nancy; Guenther, Patricia M; Tarasuk, Valerie; Reedy, Jill; Krebs-Smith, Susan M

    2015-12-01

    Recent reports have asserted that, because of energy underreporting, dietary self-report data suffer from measurement error so great that findings that rely on them are of no value. This commentary considers the amassed evidence that shows that self-report dietary intake data can successfully be used to inform dietary guidance and public health policy. Topics discussed include what is known and what can be done about the measurement error inherent in data collected by using self-report dietary assessment instruments and the extent and magnitude of underreporting energy compared with other nutrients and food groups. Also discussed is the overall impact of energy underreporting on dietary surveillance and nutritional epidemiology. In conclusion, 7 specific recommendations for collecting, analyzing, and interpreting self-report dietary data are provided: (1) continue to collect self-report dietary intake data because they contain valuable, rich, and critical information about foods and beverages consumed by populations that can be used to inform nutrition policy and assess diet-disease associations; (2) do not use self-reported energy intake as a measure of true energy intake; (3) do use self-reported energy intake for energy adjustment of other self-reported dietary constituents to improve risk estimation in studies of diet-health associations; (4) acknowledge the limitations of self-report dietary data and analyze and interpret them appropriately; (5) design studies and conduct analyses that allow adjustment for measurement error; (6) design new epidemiologic studies to collect dietary data from both short-term (recalls or food records) and long-term (food-frequency questionnaires) instruments on the entire study population to allow for maximizing the strengths of each instrument; and (7) continue to develop, evaluate, and further expand methods of dietary assessment, including dietary biomarkers and methods using new technologies.

  7. Background of Civil Defense and Current Damage Limiting Studies.

    ERIC Educational Resources Information Center

    Romm, Joseph

    A brief history of civil defense administration precedes analysis of nuclear attack conditions and the influence of protective measures. Damage limitation procedure is explained in terms of--(1) blast effects, (2) radiation doses, (3) geographical fallout distribution patterns, and (4) national shelter needs. Major concept emphasis relates to--(1)…

  8. Limitations of eddy current testing in a fast reactor environment

    NASA Astrophysics Data System (ADS)

    Wu, Tao; Bowler, John R.

    2016-02-01

    The feasibility of using eddy current probes for detecting flaws in fast nuclear reactor structures has been investigated with the aim of detecting defects immersed in electrically conductive coolant including under liquid sodium during standby. For the inspections to be viable, there is a need to use an encapsulated sensor system that can be move into position with the aid of visualization tools. The initial objective being to locate the surface to be investigated using, for example, a combination of electromagnetic sensors and sonar. Here we focus on one feature of the task in which eddy current probe impedance variations due to interaction with the external surface of a tube are evaluated in order to monitor the probe location and orientation during inspection.

  9. Growth hormone assays: current methodologies and their limitations.

    PubMed

    Bidlingmaier, Martin; Strasburger, Christian J

    2007-01-01

    Measurement of circulating growth hormone (GH) concentrations is essential in diagnosis of either GH deficiency or GH excess. The invention of immunoassays for the measurement of peptide hormones was a major breakthrough, enabling the routine analysis of GH concentrations in larger series of samples. Over the last few decades, measurement technology has evolved from less sensitive, mainly radioactive assays based on polyclonal antisera to the latest generations of highly sensitive chemiluminescence methods employing monoclonal antibodies. Unfortunately, the development of newer assays did not lead to better agreement among the results obtained by different assay methods. On the contrary, the differences tended to increase when monoclonal antibody based assays became more popular. The actual value reported for the GH concentration in a specific patient's sample still mainly depends on the method used by the respective laboratory, limiting the applicability of international consensus guidelines in clinical practice. The heterogeneity of the analyte itself, the availability of different reference preparations for calibration and the interference from matrix components such as GH binding protein are among the reasons why standardizing GH assays is difficult. An additional challenge arose from the availability of a GH receptor antagonist for the treatment of acromegaly, which is basically a mutated form of GH and therefore interferes in many GH assays. This review provides an overview on GH assays used in clinical practice, their limitations and the potential next steps towards standardization.

  10. Multivariate PAT solutions for biopharmaceutical cultivation: current progress and limitations.

    PubMed

    Mercier, Sarah M; Diepenbroek, Bas; Wijffels, Rene H; Streefland, Mathieu

    2014-06-01

    Increasingly elaborate and voluminous datasets are generated by the (bio)pharmaceutical industry and are a major challenge for application of PAT and QbD principles. Multivariate data analysis (MVDA) is required to delineate relevant process information from large multi-factorial and multi-collinear datasets. Here the key role of MVDA for industrial (bio)process data is discussed, with a focus on progress and limitations of MVDA as a PAT solution for biopharmaceutical cultivation processes. MVDA based models were proven useful and should be routinely implemented for bioprocesses. It is concluded that although the highest level of PAT with process control within its design space in real-time during manufacturing is not reached yet, MVDA will be central to reach this ultimate objective for cell cultivations. PMID:24732022

  11. Multivariate PAT solutions for biopharmaceutical cultivation: current progress and limitations.

    PubMed

    Mercier, Sarah M; Diepenbroek, Bas; Wijffels, Rene H; Streefland, Mathieu

    2014-06-01

    Increasingly elaborate and voluminous datasets are generated by the (bio)pharmaceutical industry and are a major challenge for application of PAT and QbD principles. Multivariate data analysis (MVDA) is required to delineate relevant process information from large multi-factorial and multi-collinear datasets. Here the key role of MVDA for industrial (bio)process data is discussed, with a focus on progress and limitations of MVDA as a PAT solution for biopharmaceutical cultivation processes. MVDA based models were proven useful and should be routinely implemented for bioprocesses. It is concluded that although the highest level of PAT with process control within its design space in real-time during manufacturing is not reached yet, MVDA will be central to reach this ultimate objective for cell cultivations.

  12. Fighting Sharka in Peach: Current Limitations and Future Perspectives.

    PubMed

    Cirilli, Marco; Geuna, Filippo; Babini, Anna R; Bozhkova, Valentina; Catalano, Luigi; Cavagna, Beniamino; Dallot, Sylvie; Decroocq, Véronique; Dondini, Luca; Foschi, Stefano; Ilardi, Vincenza; Liverani, Alessandro; Mezzetti, Bruno; Minafra, Angelantonio; Pancaldi, Marco; Pandolfini, Tiziana; Pascal, Thierry; Savino, Vito N; Scorza, Ralph; Verde, Ignazio; Bassi, Daniele

    2016-01-01

    Sharka, caused by Plum Pox Virus (PPV), is by far the most important infectious disease of peach [P. persica (L.) Batsch] and other Prunus species. The progressive spread of the virus in many important growing areas throughout Europe poses serious issues to the economic sustainability of stone fruit crops, peach in particular. The adoption of internationally agreed-upon rules for diagnostic tests, strain-specific monitoring schemes and spatial-temporal modeling of virus spread, are all essential for a more effective sharka containment. The EU regulations on nursery activity should be modified based on the zone delimitation of PPV presence, limiting open-field production of propagation materials only to virus-free areas. Increasing the efficiency of preventive measures should be augmented by the short-term development of resistant cultivars. Putative sources of resistance/tolerance have been recently identified in peach germplasm, although the majority of novel resistant sources to PPV-M have been found in almond. However, the complexity of introgression from related-species imposes the search for alternative strategies. The use of genetic engineering, particularly RNA interference (RNAi)-based approaches, appears as one of the most promising perspectives to introduce a durable resistance to PPV in peach germplasm, notwithstanding the well-known difficulties of in vitro plant regeneration in this species. In this regard, rootstock transformation to induce RNAi-mediated systemic resistance would avoid the transformation of numerous commercial cultivars, and may alleviate consumer resistance to the use of GM plants. PMID:27625664

  13. Treatment for spasmodic dysphonia: limitations of current approaches

    PubMed Central

    Ludlow, Christy L.

    2009-01-01

    Purpose of review Although botulinum toxin injection is the gold standard for treatment of spasmodic dysphonia, surgical approaches aimed at providing long-term symptom control have been advancing over recent years. Recent findings When surgical approaches provide greater long-term benefits to symptom control, they also increase the initial period of side effects of breathiness and swallowing difficulties. However, recent analyses of quality-of-life questionnaires in patients undergoing regular injections of botulinum toxin demonstrate that a large proportion of patients have limited relief for relatively short periods due to early breathiness and loss-of-benefit before reinjection. Summary Most medical and surgical approaches to the treatment of spasmodic dysphonia have been aimed at denervation of the laryngeal muscles to block symptom expression in the voice, and have both adverse effects as well as treatment benefits. Research is needed to identify the central neuropathophysiology responsible for the laryngeal muscle spasms in order target treatment towards the central neurological abnormality responsible for producing symptoms. PMID:19337127

  14. Fighting Sharka in Peach: Current Limitations and Future Perspectives

    PubMed Central

    Cirilli, Marco; Geuna, Filippo; Babini, Anna R.; Bozhkova, Valentina; Catalano, Luigi; Cavagna, Beniamino; Dallot, Sylvie; Decroocq, Véronique; Dondini, Luca; Foschi, Stefano; Ilardi, Vincenza; Liverani, Alessandro; Mezzetti, Bruno; Minafra, Angelantonio; Pancaldi, Marco; Pandolfini, Tiziana; Pascal, Thierry; Savino, Vito N.; Scorza, Ralph; Verde, Ignazio; Bassi, Daniele

    2016-01-01

    Sharka, caused by Plum Pox Virus (PPV), is by far the most important infectious disease of peach [P. persica (L.) Batsch] and other Prunus species. The progressive spread of the virus in many important growing areas throughout Europe poses serious issues to the economic sustainability of stone fruit crops, peach in particular. The adoption of internationally agreed-upon rules for diagnostic tests, strain-specific monitoring schemes and spatial–temporal modeling of virus spread, are all essential for a more effective sharka containment. The EU regulations on nursery activity should be modified based on the zone delimitation of PPV presence, limiting open-field production of propagation materials only to virus-free areas. Increasing the efficiency of preventive measures should be augmented by the short-term development of resistant cultivars. Putative sources of resistance/tolerance have been recently identified in peach germplasm, although the majority of novel resistant sources to PPV-M have been found in almond. However, the complexity of introgression from related-species imposes the search for alternative strategies. The use of genetic engineering, particularly RNA interference (RNAi)-based approaches, appears as one of the most promising perspectives to introduce a durable resistance to PPV in peach germplasm, notwithstanding the well-known difficulties of in vitro plant regeneration in this species. In this regard, rootstock transformation to induce RNAi-mediated systemic resistance would avoid the transformation of numerous commercial cultivars, and may alleviate consumer resistance to the use of GM plants.

  15. Fighting Sharka in Peach: Current Limitations and Future Perspectives

    PubMed Central

    Cirilli, Marco; Geuna, Filippo; Babini, Anna R.; Bozhkova, Valentina; Catalano, Luigi; Cavagna, Beniamino; Dallot, Sylvie; Decroocq, Véronique; Dondini, Luca; Foschi, Stefano; Ilardi, Vincenza; Liverani, Alessandro; Mezzetti, Bruno; Minafra, Angelantonio; Pancaldi, Marco; Pandolfini, Tiziana; Pascal, Thierry; Savino, Vito N.; Scorza, Ralph; Verde, Ignazio; Bassi, Daniele

    2016-01-01

    Sharka, caused by Plum Pox Virus (PPV), is by far the most important infectious disease of peach [P. persica (L.) Batsch] and other Prunus species. The progressive spread of the virus in many important growing areas throughout Europe poses serious issues to the economic sustainability of stone fruit crops, peach in particular. The adoption of internationally agreed-upon rules for diagnostic tests, strain-specific monitoring schemes and spatial–temporal modeling of virus spread, are all essential for a more effective sharka containment. The EU regulations on nursery activity should be modified based on the zone delimitation of PPV presence, limiting open-field production of propagation materials only to virus-free areas. Increasing the efficiency of preventive measures should be augmented by the short-term development of resistant cultivars. Putative sources of resistance/tolerance have been recently identified in peach germplasm, although the majority of novel resistant sources to PPV-M have been found in almond. However, the complexity of introgression from related-species imposes the search for alternative strategies. The use of genetic engineering, particularly RNA interference (RNAi)-based approaches, appears as one of the most promising perspectives to introduce a durable resistance to PPV in peach germplasm, notwithstanding the well-known difficulties of in vitro plant regeneration in this species. In this regard, rootstock transformation to induce RNAi-mediated systemic resistance would avoid the transformation of numerous commercial cultivars, and may alleviate consumer resistance to the use of GM plants. PMID:27625664

  16. Current limitations and challenges in nanowaste detection, characterisation and monitoring.

    PubMed

    Part, Florian; Zecha, Gudrun; Causon, Tim; Sinner, Eva-Kathrin; Huber-Humer, Marion

    2015-09-01

    Engineered nanomaterials (ENMs) are already extensively used in diverse consumer products. Along the life cycle of a nano-enabled product, ENMs can be released and subsequently accumulate in the environment. Material flow models also indicate that a variety of ENMs may accumulate in waste streams. Therefore, a new type of waste, so-called nanowaste, is generated when end-of-life ENMs and nano-enabled products are disposed of. In terms of the precautionary principle, environmental monitoring of end-of-life ENMs is crucial to allow assessment of the potential impact of nanowaste on our ecosystem. Trace analysis and quantification of nanoparticulate species is very challenging because of the variety of ENM types that are used in products and low concentrations of nanowaste expected in complex environmental media. In the framework of this paper, challenges in nanowaste characterisation and appropriate analytical techniques which can be applied to nanowaste analysis are summarised. Recent case studies focussing on the characterisation of ENMs in waste streams are discussed. Most studies aim to investigate the fate of nanowaste during incineration, particularly considering aerosol measurements; whereas, detailed studies focusing on the potential release of nanowaste during waste recycling processes are currently not available. In terms of suitable analytical methods, separation techniques coupled to spectrometry-based methods are promising tools to detect nanowaste and determine particle size distribution in liquid waste samples. Standardised leaching protocols can be applied to generate soluble fractions stemming from solid wastes, while micro- and ultrafiltration can be used to enrich nanoparticulate species. Imaging techniques combined with X-ray-based methods are powerful tools for determining particle size, morphology and screening elemental composition. However, quantification of nanowaste is currently hampered due to the problem to differentiate engineered from

  17. Current limitations and challenges in nanowaste detection, characterisation and monitoring.

    PubMed

    Part, Florian; Zecha, Gudrun; Causon, Tim; Sinner, Eva-Kathrin; Huber-Humer, Marion

    2015-09-01

    Engineered nanomaterials (ENMs) are already extensively used in diverse consumer products. Along the life cycle of a nano-enabled product, ENMs can be released and subsequently accumulate in the environment. Material flow models also indicate that a variety of ENMs may accumulate in waste streams. Therefore, a new type of waste, so-called nanowaste, is generated when end-of-life ENMs and nano-enabled products are disposed of. In terms of the precautionary principle, environmental monitoring of end-of-life ENMs is crucial to allow assessment of the potential impact of nanowaste on our ecosystem. Trace analysis and quantification of nanoparticulate species is very challenging because of the variety of ENM types that are used in products and low concentrations of nanowaste expected in complex environmental media. In the framework of this paper, challenges in nanowaste characterisation and appropriate analytical techniques which can be applied to nanowaste analysis are summarised. Recent case studies focussing on the characterisation of ENMs in waste streams are discussed. Most studies aim to investigate the fate of nanowaste during incineration, particularly considering aerosol measurements; whereas, detailed studies focusing on the potential release of nanowaste during waste recycling processes are currently not available. In terms of suitable analytical methods, separation techniques coupled to spectrometry-based methods are promising tools to detect nanowaste and determine particle size distribution in liquid waste samples. Standardised leaching protocols can be applied to generate soluble fractions stemming from solid wastes, while micro- and ultrafiltration can be used to enrich nanoparticulate species. Imaging techniques combined with X-ray-based methods are powerful tools for determining particle size, morphology and screening elemental composition. However, quantification of nanowaste is currently hampered due to the problem to differentiate engineered from

  18. Influence of the startup instant of quench in a superconducting current limiter

    SciTech Connect

    Leveque, J.; Netter, D.; Rezzoug, A.; Caron, J.P.; Sargos, F.M.

    1996-09-01

    The influence of the startup instant of the quench in a superconducting current limiter is studied. The heat transfer equation is numerically solved, using finite difference method, and taking the effects of current sharing into account. The results show the importance of this instant on the dissipated power, the temperature-increase and on the efficiency of the current limitation.

  19. Evaluation of Ferrite Chip Beads as Surge Current Limiters in Circuits with Tantalum Capacitors

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2014-01-01

    Limiting resistors are currently required to be connected in series with tantalum capacitors to reduce the risk of surge current failures. However, application of limiting resistors decreases substantially the efficiency of the power supply systems. An ideal surge current limiting device should have a negligible resistance for DC currents and high resistance at frequencies corresponding to transients in tantalum capacitors. This work evaluates the possibility of using chip ferrite beads (FB) as such devices. Twelve types of small size FBs from three manufacturers were used to evaluate their robustness under soldering stresses and at high surge current spikes associated with transients in tantalum capacitors. Results show that FBs are capable to withstand current pulses that are substantially greater than the specified current limits. However, due to a sharp decrease of impedance with current, FBs do not reduce surge currents to the required level that can be achieved with regular resistors.

  20. To eat or not to eat. A comparison of current and former animal product limiters.

    PubMed

    Haverstock, Katie; Forgays, Deborah Kirby

    2012-06-01

    In this exploratory study, we compared current and former pescatarians, vegetarians and vegans on a number of variables including the motivations for their food choices. Participants were recruited via online message boards as well as through snowball sampling. Of the 247 participants, 196 were currently limiting animal products and 51 were former animal product limiters. Current limiters were more likely to have made a gradual rather than abrupt transition to animal product limitation and were more likely to have joined a vegetarian or vegan group than former limiters. Furthermore, current limiters indicated that their eating pattern was a part of their self identity. These findings shed light on the differences among current and former vegans and vegetarians and can inform individuals interested in promoting animal product limitation for health or ethical reasons. PMID:22387715

  1. 6. 6 kV/1. 5 kA-class superconducting fault current limiter development

    SciTech Connect

    Ito, D.; Yoneda, E.S.; Tsurunaga, K.; Tada, T. ); Hara, T.; Ohkuma, T.; Yamamoto, T. )

    1992-01-01

    This paper reports that the authors have developed and tested a 6.6 kV/1.5 kA-class fault current limiter wound with a 42-strand AC superconducting wire having ultra-fine MbTi filaments in a high resistivity matrix. In experiments, voltages up to 7.2 kV were applied to the limiter with phase angles of 0, 45, and 90 degrees. The limiter was able to limit the fault current to 1.8 kA successfully from the 55 kA short-circuit current that would flow in a circuit without limiter.

  2. Model of current-limited negative differential resistance in oxide-based resistance-switching devices

    NASA Astrophysics Data System (ADS)

    Chen, Frederick T.

    2015-01-01

    Resistance-switching devices such as resistive random access memories (RRAMs) exhibit the ability to rapidly reduce resistance upon exceeding a threshold voltage, as part of the SET operation. For oxide-based RRAMs, the progressive generation of defects during SET requires strict regulation of the current, e.g., by a transistor, in order to avoid irreversible breakdown. In doing so, the current-limiting device itself takes some voltage burden. The observed negative differential resistance for both the initial (forming) and regular SET operations can be analytically explained with a basic circuit model for the current-limited switching element, linking the voltage transfer to the current-limiting device with the degree of current rise. Consequently, it is found that RRAM operation current is a vital consideration for the reliability of the current-limiting device.

  3. 40 CFR 74.25 - Current promulgated SO2 emissions limit.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Current promulgated SO2 emissions... promulgated SO2 emissions limit. The designated representative shall submit the following data: (a) Current promulgated SO2 emissions limit of the combustion source, expressed in lbs/mmBtu, which shall be the...

  4. 40 CFR 74.25 - Current promulgated SO2 emissions limit.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Current promulgated SO2 emissions... promulgated SO2 emissions limit. The designated representative shall submit the following data: (a) Current promulgated SO2 emissions limit of the combustion source, expressed in lbs/mmBtu, which shall be the...

  5. 40 CFR 74.25 - Current promulgated SO2 emissions limit.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Current promulgated SO2 emissions... promulgated SO2 emissions limit. The designated representative shall submit the following data: (a) Current promulgated SO2 emissions limit of the combustion source, expressed in lbs/mmBtu, which shall be the...

  6. Medical interpreters: improvements to address access, equity, and quality of care for limited-English-proficient patients.

    PubMed

    VanderWielen, Lynn M; Enurah, Alexander S; Rho, Helen Y; Nagarkatti-Gude, David R; Michelsen-King, Patricia; Crossman, Steven H; Vanderbilt, Allison A

    2014-10-01

    Limited-English-proficient (LEP) patients in the United States experience a variety of health care disparities associated with language barriers, including reduced clinical encounter time and substandard medical treatment compared with their English-speaking counterparts. In most current U.S. health care settings, interpretation services are provided by personnel ranging from employed professional interpreters to untrained, ad hoc interpreters such as friends, family, or medical staff. Studies have demonstrated that untrained individuals commit many interpretation errors that may critically compromise patient safety and ultimately prove to be life-threatening. Despite documented risks, the U.S. health care system lacks a required standardized certification for medical interpreters. The authors propose that the standardization of medical interpreter training and certification would substantially reduce the barriers to equitable care experienced by LEP patients in the U.S. health care system, including the occurrence of preventable clinical errors. Recent efforts of the U.S. federal court system are cited as a successful and realistic example of how these goals may be achieved. As guided by the evolution of the federal court interpreting certification program, subsequent research will be required to demonstrate the improvements and challenges that would result from national certification standards and policy for medical interpreters. Research should examine cost-effectiveness and ensure that certified interpreting services are appropriately used by health care practitioners. Ongoing commitment is required from lawmakers, health care providers, and researchers to remove barriers to care and to demand that equity remain a consistent goal of our health care system.

  7. Over-limiting currents and deionization "shocks" in current-induced polarization: local-equilibrium analysis.

    PubMed

    Yaroshchuk, Andriy

    2012-11-15

    The problem is considered theoretically of dynamics of current-induced concentration polarization of interfaces between ideally perm-selective and non-ideally perm-selective ("leaky") ion-exchange media in binary electrolyte solutions under galvanostatic conditions and at negligible volume flow. In contrast to the previous studies, the analysis is systematically carried out in terms of local thermodynamic equilibrium in the approximation of local electric neutrality in virtual solution. For macroscopically homogeneous media, this enables one to obtain model-independent results in quadratures for the stationary state as well as an approximate scaling-form solution for the transient response to the step-wise increase in electric-current density. These results are formulated in terms of such phenomenological properties of the "leaky" medium as ion transport numbers, diffusion permeability to salt and specific chemical capacity. An easy-to-solve numerically 1D PDE is also formulated in the same terms. A systematic parametric study is carried out within the scope of fine-pore model of "leaky" medium in terms of such properties as volumetric concentration of fixed electric charges and diffusivities of ions of symmetrical electrolyte. While previous studies paid principal attention to the shape and propagation rate of the so-called deionization "shocks", we also consider in detail the time evolution of voltage drop and interface salt concentration. Our analysis confirms the previously predicted pattern of propagating deionization "shocks" within the "leaky" medium but also reveals several novel features. In particular, we demonstrate that the deionization-shock pattern is really pronounced only at intermediate ratios of fixed-charge concentration to the initial salt concentration and at quite high steady-state voltages where the model used in this and previous studies is applicable only at relatively early stages of concentration-polarization process. PMID:22947188

  8. Transient Electromagnetic Phenomena during Current Limiting Process in YBCO Thin Film

    NASA Astrophysics Data System (ADS)

    Ichiki, Y.; Ohsaki, H.

    2006-06-01

    In order to design a reliable and high-performance fault current limiter, it is necessary to estimate the influences of the inhomogeneous superconducting properties on the current limiting process and S-N transition. This paper describes the measurements of transient electromagnetic phenomena in YBCO thin film using pick-up coils to observe current-sharing process and change of current distribution. At first current distribution in a steady state was measured. And then transient phenomena caused by applying an overcurrent to YBCO thin film covered with a silver layer were measured.

  9. A double-stage start-up structure to limit the inrush current used in current mode charge pump

    NASA Astrophysics Data System (ADS)

    Cong, Liu; Xinquan, Lai; Hanxiao, Du; Yuan, Chi

    2016-06-01

    A double-stage start-up structure to limit the inrush current used in current-mode charge pump with wide input range, fixed output and multimode operation is presented in this paper. As a widely utilized power source implement, a Li-battery is always used as the power supply for chips. Due to the internal resistance, a potential drop will be generated at the input terminal of the chip with an input current. A false shut down with a low supply voltage will happen if the input current is too large, leading to the degradation of the Li-battery's service life. To solve this problem, the inrush current is limited by introducing a new start-up state. All of the circuits have been implemented with the NUVOTON 0.6 μm CMOS process. The measurement results show that the inrush current can be limited below 1 A within all input supply ranges, and the power efficiency is higher than the conventional structure. Project supported by the National Natural Science Foundation of China (No. 61106026).

  10. Shrinking Sea Ice, Thawing Permafrost, Bigger Storms, and Extremely Limited Data - Addressing Information Needs of Stakeholders in Western Alaska Through Participatory Decisions and Collaborative Science.

    NASA Astrophysics Data System (ADS)

    Murphy, K. A.; Reynolds, J.

    2015-12-01

    Communities, Tribes, and decision makers in coastal western Alaska are being impacted by declining sea ice, sea level rise, changing storm patterns and intensities, and increased rates of coastal erosion. Relative to their counterparts in the contiguous USA, their ability to plan for and respond to these changes is constrained by the region's generally meager or non-existent information base. Further, the information needs and logistic challenges are of a scale that perhaps can be addressed only through strong, strategic collaboration. Landscape Conservation Cooperatives (LCCs) are fundamentally about applied science and collaboration, especially collaborative decision making. The Western Alaska LCC has established a process of participatory decision making that brings together researchers, agency managers, local experts from Tribes and field specialists to identify and prioritize shared information needs; develop a course of action to address them by using the LCC's limited resources to catalyze engagement, overcome barriers to progress, and build momentum; then ensure products are delivered in a manner that meets decision makers' needs. We briefly review the LCC's activities & outcomes from the stages of (i) collaborative needs assessment (joint with the Alaska Climate Science Center and the Alaska Ocean Observing System), (ii) strategic science activities, and (iii) product refinement and delivery. We discuss lessons learned, in the context of our recent program focused on 'Changes in Coastal Storms and Their Impacts' and current collaborative efforts focused on delivery of Coastal Resiliency planning tools and results from applied science projects. Emphasis is given to the various key interactions between scientists and decision makers / managers that have been promoted by this process to ensure alignment of final products to decision maker needs.

  11. How Does the Capability Approach Address Current Issues in Special Educational Needs, Disability and Inclusive Education Field?

    ERIC Educational Resources Information Center

    Norwich, Brahm

    2014-01-01

    This paper aims to examine what the capability approach has to offer to the field of special needs and inclusive education. Several key questions are addressed: can the capability approach replace the language of needs and rights; whether the capability approach can address key issues in the field of disabilities and difficulties in education and…

  12. Addressing Concerns.

    ERIC Educational Resources Information Center

    Cronin, Greg; Helmig, Mary; Kaplan, Bill; Kosch, Sharon

    2002-01-01

    Four camp directors discuss how the September 11 tragedy and current world events will affect their camps. They describe how they are addressing safety concerns, working with parents, cooperating with outside agencies, hiring and screening international staff, and revising emergency plans. Camps must continue to offer community and support to…

  13. Superconducting technology for overcurrent limiting in a 25 kA current injection system

    NASA Astrophysics Data System (ADS)

    Heydari, Hossein; Faghihi, Faramarz; Sharifi, Reza; Poursoltanmohammadi, Amir Hossein

    2008-09-01

    Current injection transformer (CIT) systems are within the major group of the standard type test of high current equipment in the electrical industry, so their performance becomes very important. When designing high current systems, there are many factors to be considered from which their overcurrent protection must be ensured. The output of a CIT is wholly dependent on the impedance of the equipment under test (EUT). Therefore current flow beyond the allowable limit can occur. The present state of the art provides an important guide to developing current limiters not only for the grid application but also in industrial equipment. This paper reports the state of the art in the technology available that could be developed into an application of superconductivity for high current equipment (CIT) protection with no test disruption. This will result in a greater market choice and lower costs for equipment protection solutions, reduced costs and improved system reliability. The paper will also push the state of the art by using two distinctive circuits, closed-core and open-core, for overcurrent protection of a 25 kA CIT system, based on a flux-lock-type superconducting fault current limiter (SFCL) and magnetic properties of high temperature superconducting (HTS) elements. An appropriate location of the HTS element will enhance the rate of limitation with the help of the magnetic field generated by the CIT output busbars. The calculation of the HTS parameters for overcurrent limiting is also performed to suit the required current levels of the CIT.

  14. Estimating Heat and Mass Transfer Processes in Green Roof Systems: Current Modeling Capabilities and Limitations (Presentation)

    SciTech Connect

    Tabares Velasco, P. C.

    2011-04-01

    This presentation discusses estimating heat and mass transfer processes in green roof systems: current modeling capabilities and limitations. Green roofs are 'specialized roofing systems that support vegetation growth on rooftops.'

  15. Limiting electron beam current for cyclic induction acceleration in a constant guide field

    SciTech Connect

    Kanunnikov, V.N.

    1982-09-01

    Theoretical relations are derived for the limiting beam current in a cyclic induction accelerator (CIA) with a constant guide field. The calculations are in agreement with the available experimental data. It is shown that the limiting average beam current in a CIA is of the order of 100 microamperes, i.e., the level attained in microtrons and linear accelerators. The CIA may find industrial applications.

  16. 40 CFR 74.25 - Current promulgated SO 2 emissions limit.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Current promulgated SO 2 emissions... PROGRAMS (CONTINUED) SULFUR DIOXIDE OPT-INS Allowance Calculations for Combustion Sources § 74.25 Current promulgated SO 2 emissions limit. The designated representative shall submit the following data: (a)...

  17. 40 CFR 74.25 - Current promulgated SO 2 emissions limit.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Current promulgated SO 2 emissions... PROGRAMS (CONTINUED) SULFUR DIOXIDE OPT-INS Allowance Calculations for Combustion Sources § 74.25 Current promulgated SO 2 emissions limit. The designated representative shall submit the following data: (a)...

  18. 40 CFR 450.21 - Effluent limitations reflecting the best practicable technology currently available (BPT).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... stormwater volume and velocity to minimize soil erosion in order to minimize pollutant discharges; (2... limitations reflecting the best practicable technology currently available (BPT). Except as provided in 40 CFR... the best practicable control technology currently available (BPT). (a) Erosion and sediment...

  19. Space-charge limited current in the series resistance of GaAs solar cells

    NASA Astrophysics Data System (ADS)

    Folkes, P. A.; Olver, K.

    2013-12-01

    We report the observation of space-charge limited current in the current-voltage characteristics of GaAs solar cells as evidenced by an abrupt decrease in the series resistance, a concurrent steep increase in the dark current at a threshold voltage and the observation of a quadratic dependence of the dark current on the voltage across the series resistance above threshold. The abrupt decrease in the series resistance at threshold, results in the observation of negative differential resistance and a subsequent hysteresis in the current-voltage characteristics. Auger electron spectroscopy analysis shows that the space-charge limited current can be attributed to a thin insulating CrAs layer at the contact/semiconductor interface.

  20. Addressing the Limit of Detectability of Residual Oxide Discontinuities in Friction Stir Butt Welds of Aluminum using Phased Array Ultrasound

    NASA Technical Reports Server (NTRS)

    Johnston, P. H.

    2008-01-01

    This activity seeks to estimate a theoretical upper bound of detectability for a layer of oxide embedded in a friction stir weld in aluminum. The oxide is theoretically modeled as an ideal planar layer of aluminum oxide, oriented normal to an interrogating ultrasound beam. Experimentally-measured grain scattering level is used to represent the practical noise floor. Echoes from naturally-occurring oxides will necessarily fall below this theoretical limit, and must be above the measurement noise to be potentially detectable.

  1. Progress on superconducting current limitation project for the French electrical grid

    NASA Astrophysics Data System (ADS)

    Verhaege, T.; Cottevieille, C.; Weber, W.; Thomas, P.; Therond, P. G.; Laumond, Y.; Bekhaled, M.; Pham, V. D.

    1994-07-01

    Electricite de France, GEC ALSTHOM and Alcatel Alsthom Recherche, initiated in 1992 a project for the definition, experimental validation and economic evaluation of superconducting fault current limiters adapted to the french grid system. As a first step, a device of 63 kV-1.25 kA is investigated, which has the function to limit the 25 kA fault current at 5300 A(peak). A very compact and low-inductance design has been selected, based on resistive limitation. Considerations concerning the general design, conductor protection, high voltage insulation, cryogenic system and interaction with the grid developed in this paper.

  2. Relativistic solutions for one- and two-dimensional space-charge limited current in coaxial diode

    SciTech Connect

    Yang, Zhanfeng; Liu, Guozhi; Shao, Hao; Yan, Teng; Zhang, Yuchuan

    2013-05-15

    This paper reports the two-dimensional physics and space-charge limited current (SLC) of coaxial diodes with a finite-length emitter. A full-voltage and one-dimensional approximate solution is first obtained by matching the non-relativistic solution to the super-relativistic solution. Including the effects of fields induced by the anode current and the beam itself yields the pinch-limited current in the coaxial diode. The SLC of a practically applied coaxial diode with a finite length emitter is obtained by a semi-analytical method. The solutions well agree with numerical solutions and particle-in-cell simulations.

  3. An upper bound to time-averaged space-charge limited diode currents

    NASA Astrophysics Data System (ADS)

    Griswold, M. E.; Fisch, N. J.; Wurtele, J. S.

    2010-11-01

    The Child-Langmuir law limits the steady-state current density across a one-dimensional planar diode. While it is known that the peak current density can surpass this limit when the boundary conditions vary in time, it remains an open question of whether the average current can violate the Child-Langmuir limit under time-dependent conditions. For the case where the applied voltage is constant but the electric field at the cathode is allowed to vary in time, one-dimensional particle-in-cell simulations suggest that such a violation is impossible. Although a formal proof is not given, an upper bound on the time-averaged current density is offered.

  4. Over-limiting Current and Control of Dendritic Growth by Surface Conduction in Nanopores

    PubMed Central

    Han, Ji-Hyung; Khoo, Edwin; Bai, Peng; Bazant, Martin Z.

    2014-01-01

    Understanding over-limiting current (faster than diffusion) is a long-standing challenge in electrochemistry with applications in desalination and energy storage. Known mechanisms involve either chemical or hydrodynamic instabilities in unconfined electrolytes. Here, it is shown that over-limiting current can be sustained by surface conduction in nanopores, without any such instabilities, and used to control dendritic growth during electrodeposition. Copper electrodeposits are grown in anodized aluminum oxide membranes with polyelectrolyte coatings to modify the surface charge. At low currents, uniform electroplating occurs, unaffected by surface modification due to thin electric double layers, but the morphology changes dramatically above the limiting current. With negative surface charge, growth is enhanced along the nanopore surfaces, forming surface dendrites and nanotubes behind a deionization shock. With positive surface charge, dendrites avoid the surfaces and are either guided along the nanopore centers or blocked from penetrating the membrane. PMID:25394685

  5. Over-limiting current and control of dendritic growth by surface conduction in nanopores.

    PubMed

    Han, Ji-Hyung; Khoo, Edwin; Bai, Peng; Bazant, Martin Z

    2014-01-01

    Understanding over-limiting current (faster than diffusion) is a long-standing challenge in electrochemistry with applications in desalination and energy storage. Known mechanisms involve either chemical or hydrodynamic instabilities in unconfined electrolytes. Here, it is shown that over-limiting current can be sustained by surface conduction in nanopores, without any such instabilities, and used to control dendritic growth during electrodeposition. Copper electrodeposits are grown in anodized aluminum oxide membranes with polyelectrolyte coatings to modify the surface charge. At low currents, uniform electroplating occurs, unaffected by surface modification due to thin electric double layers, but the morphology changes dramatically above the limiting current. With negative surface charge, growth is enhanced along the nanopore surfaces, forming surface dendrites and nanotubes behind a deionization shock. With positive surface charge, dendrites avoid the surfaces and are either guided along the nanopore centers or blocked from penetrating the membrane.

  6. An upper bound to time-averaged space-charge limited diode currents

    SciTech Connect

    Griswold, M. E.; Fisch, N. J.; Wurtele, J. S.

    2010-11-15

    The Child-Langmuir law limits the steady-state current density across a one-dimensional planar diode. While it is known that the peak current density can surpass this limit when the boundary conditions vary in time, it remains an open question of whether the average current can violate the Child-Langmuir limit under time-dependent conditions. For the case where the applied voltage is constant but the electric field at the cathode is allowed to vary in time, one-dimensional particle-in-cell simulations suggest that such a violation is impossible. Although a formal proof is not given, an upper bound on the time-averaged current density is offered.

  7. Scanning fast and slow: current limitations of 3 Tesla functional MRI and future potential

    NASA Astrophysics Data System (ADS)

    Boubela, Roland N.; Kalcher, Klaudius; Nasel, Christian; Moser, Ewald

    2014-02-01

    Functional MRI at 3T has become a workhorse for the neurosciences, e.g., neurology, psychology, and psychiatry, enabling non-invasive investigation of brain function and connectivity. However, BOLD-based fMRI is a rather indirect measure of brain function, confounded by fluctuation related signals, e.g. head or brain motion, brain pulsation, blood flow, intermixed with susceptibility differences close or distant to the region of neuronal activity. Even though a plethora of preprocessing strategies have been published to address these confounds, their efficiency is still under discussion. In particular, physiological signal fluctuations closely related to brain supply may mask BOLD signal changes related to "true" neuronal activation. Here we explore recent technical and methodological advancements aimed at disentangling the various components, employing fast multiband vs. standard EPI, in combination with fast temporal ICA.Our preliminary results indicate that fast (TR< 0.5s) scanning may help to identify and eliminate physiologic components, increasing tSNR and functional contrast. In addition, biological variability can be studied and task performance better correlated to other measures. This should increase specificity and reliability in fMRI studies. Furthermore, physiological signal changes during scanning may then be recognized as a source of information rather than a nuisance. As we are currently still undersampling the complexity of the brain, even at a rather coarse macroscopic level, we should be very cautious in the interpretation of neuroscientific findings, in particular when comparing different groups (e.g., age, sex, medication, pathology, etc.). From a technical point of view our goal should be to sample brain activity at layer specific resolution with low TR, covering as much of the brain as possible without violating SAR limits. We hope to stimulate discussion towards a better understanding and a more quantitative use of fMRI.

  8. Limiting efficiencies of GaInP/GaAs/Ge up-conversion systems: Addressing the issue of radiative coupling

    NASA Astrophysics Data System (ADS)

    Lan, Dongchen; Green, Martin A.

    2016-09-01

    Recent work proposed up-conversion of sunlight through low-band-gap solar cells in combination with a large-band-gap light-emitting diode (LED), with one possibility being the use of a GaAs/Ge tandem photovoltaic device to drive a GaInP LED. One-sun limiting efficiencies for a GaInP bifacial solar cell with such an up-converter attached to its rear are reported for varying band-gap of GaInP junctions, both when there are radiative couplings between cells in the rear up-converter and when there are not. With a maximum theoretical efficiency of 44%, it is shown that the top cell's band-gap is a trade-off and radiative coupling in the rear up-converter reduces the efficiency, where physical reasons are given as is insight into the practice.

  9. Hybrid superconducting a.c. current limiter extrapolation 63 kV-1 250 A

    NASA Astrophysics Data System (ADS)

    Tixador, P.; Levêque, J.; Brunet, Y.; Pham, V. D.

    1994-04-01

    Following the developement of a.c. superconducting wires a.c. current superconducting limiters have emerged. These limiters limit the fault currents nearly instantaneously, without detection nor order giver and may be suitable for high voltages. They are based on the natural transition from the superconducting state to the normal resistive state by overstepping the critical current of a superconducting coil which limits or triggers the limitation. Our limiter device consists essentially of two copper windings coupled through a saturable magnetic circuit and of a non inductively wound superconducting coil with a reduced current compared to the line current. This design allows a simple superconducting cable and reduced cryogenic losses but the dielectric stresses are high during faults. A small model (150 V/50 A) has experimentally validated our design. An industrial scale current limiter is designed and the comparisons between this design and other superconducting current limiters are given. Les courants de court-circuit sur les grands réseaux électriques ne cessent d'augmenter. Dans ce contexte sont apparus les limiteurs supraconducteurs de courant suite au développement des brins supraconducteurs alternatifs. Ces limiteurs peuvent limiter les courants de défaut presque instantanément, sans détection de défaut ni donneur d'ordre et ils sont extrapolables aux hautes tensions. Ils sont fondés sur la transition naturelle de l'état supraconducteur à l'état normal très résistif par dépassement du courant critique d'un enroulement supraconducteur qui limite ou déclenche la limitation. Notre limiteur est composé de deux enroulements en cuivre couplés par un circuit magnétique saturable et d'une bobine supraconductrice à courant réduit par rapport au courant de la ligne. Cette conception permet un câble supraconducteur simple et des pertes cryogéniques réduites mais les contraintes diélectriques en régime de défaut sont importantes. Une maquette

  10. Regulatory approaches to obesity prevention: A systematic overview of current laws addressing diet-related risk factors in the European Union and the United States.

    PubMed

    Sisnowski, Jana; Handsley, Elizabeth; Street, Jackie M

    2015-06-01

    High prevalence of overweight and obesity remains a significant international public health problem. Law has been identified as a tool for obesity prevention and selected high-profile measures have been reported. However, the nature and extent of enacted legislation internationally are unclear. This research provides an overview of regulatory approaches enacted in the United States, the European Union, and EU Member States since 2004. To this end, relevant databases of primary and secondary legislation were systematically searched to identify and explore laws addressing dietary risk factors for obesity. Across jurisdictions, current regulatory approaches to obesity prevention are limited in reach and scope. Target groups are rarely the general population, but instead sub-populations in government-supported settings. Consumer information provision is preferred over taxation and marketing restrictions other than the regulation of health and nutrition claims. In the EU in particular, product reformulation with industry consent has also emerged as a popular small-scale measure. While consistent and widespread use of law is lacking, governments have employed a range of regulatory measures in the name of obesity prevention, indicating that there is, in principle, political will. Results from this study may serve as a starting point for future research and policy development. PMID:25963556

  11. Regulatory approaches to obesity prevention: A systematic overview of current laws addressing diet-related risk factors in the European Union and the United States.

    PubMed

    Sisnowski, Jana; Handsley, Elizabeth; Street, Jackie M

    2015-06-01

    High prevalence of overweight and obesity remains a significant international public health problem. Law has been identified as a tool for obesity prevention and selected high-profile measures have been reported. However, the nature and extent of enacted legislation internationally are unclear. This research provides an overview of regulatory approaches enacted in the United States, the European Union, and EU Member States since 2004. To this end, relevant databases of primary and secondary legislation were systematically searched to identify and explore laws addressing dietary risk factors for obesity. Across jurisdictions, current regulatory approaches to obesity prevention are limited in reach and scope. Target groups are rarely the general population, but instead sub-populations in government-supported settings. Consumer information provision is preferred over taxation and marketing restrictions other than the regulation of health and nutrition claims. In the EU in particular, product reformulation with industry consent has also emerged as a popular small-scale measure. While consistent and widespread use of law is lacking, governments have employed a range of regulatory measures in the name of obesity prevention, indicating that there is, in principle, political will. Results from this study may serve as a starting point for future research and policy development.

  12. Design, Fabrication and Testing of a Superconducting Fault Current Limiter (SFCL)

    SciTech Connect

    Gouge, M..; Schwenterly, S.W.; Hazelton, D.

    2011-06-15

    The purpose of this project was to conduct R&D on specified components and provide technical design support to a SuperPower team developing a high temperature superconducting Fault Current Limiter (SFCL). ORNL teamed with SuperPower, Inc. on a Superconductivity Partnerships with Industry (SPI) proposal for the SFCL that was submitted to DOE and approved in FY 2003. A contract between DOE and SuperPower, Inc. was signed on July 14, 2003 to design, fabricate and test the SFCL. This device employs high temperature superconducting (HTS) elements and SuperPower's proprietary technology. The program goal was to demonstrate a device that will address a broad range of the utility applications and meet utility industry requirements. This DOE-sponsored Superconductivity Partnership with Industry project would positively impact electric power transmission reliability and security by introducing a new element in the grid that can significantly mitigate fault currents and provide lower cost solutions for grid protection. The project will conduct R&D on specified components and provide technical design support to a SuperPower-led team developing a SFCL as detailed in tasks 1-5 below. Note the SuperPower scope over the broad SPI project is much larger than that shown below which indicates only the SuperPower tasks that are complementary to the ORNL tasks. SuperPower is the Project Manager for the SFCL program, and is responsible for completion of the project on schedule and budget. The scope of work for ORNL is to provide R&D support for the SFCL in the following four broad areas: (1) Assist with high voltage subsystem R&D, design, fabrication and testing including characterization of the general dielectric performance of LN2 and component materials; (2) Consult on cryogenic subsystem R&D, design, fabrication and testing; (3) Participate in project conceptual and detailed design reviews; and (4) Guide commercialization by participation on the Technical Advisory Board (TAB). Super

  13. Proposal of rectifier type superconducting fault current limiter with non-inductive reactor (SFCL)

    NASA Astrophysics Data System (ADS)

    Mohammad Salim, Khosru; Muta, Itsuya; Hoshino, Tsutomu; Nakamura, Taketsune; Yamada, Masato

    2004-03-01

    A rectifier type superconducting fault current limiter (SFCL) with non-inductive reactor has been proposed. The concept behind this SFCL is the appearance of high impedance during non-superconducting state of the coil. In a hybrid bridge circuit, two superconducting coils connected in anti-parallel: a trigger coil and a limiting coil. Both the coils are magnetically coupled with each other and have same number of turns. There is almost zero flux inside the core and therefore the total inductance is small during normal operation. At fault time when the trigger coil current reaches to a certain level, the trigger coil changes from superconducting state to normal state. This super-to-normal transition of the trigger coil changes the current ratio of the coils and therefore the flux inside the reactor is no longer zero. So, the equivalent impedance of both the coils increased thus limits the fault current. We have carried out computer simulation using EMTDC and observed the results. A preliminary experiment has already been performed using copper wired reactor with simulated super-to-normal transition resistance and magnetic switches. Both the simulation and preliminary experiment shows good results. The advantage of using hybrid bridge circuit is that the SFCL can also be used as circuit breaker. Two separate bridge circuit can be used for both trigger coil and the limiter coil. In such a case, the trigger coil can be shutdown immediately after the fault to reduce heat and thus reduce the recovery time. Again, at the end of fault when the SFCL needs to re-enter to the grid, turning off the trigger circuit in the two-bridge configuration the inrush current can be reduced. This is because the current only flows through the limiting coil. Another advantage of this type of SFCL is that no voltage sag will appear during load increasing time as long as the load current stays below the trigger current level.

  14. Seeing the forest for the trees: the limitations of phylogenies in comparative biology. (American Society of Naturalists Address).

    PubMed

    Losos, Jonathan B

    2011-06-01

    The past 30 years have seen a revolution in comparative biology. Before that time, systematics was not at the forefront of the biological sciences, and few scientists considered phylogenetic relationships when investigating evolutionary questions. By contrast, systematic biology is now one of the most vigorous disciplines in biology, and the use of phylogenies not only is requisite in macroevolutionary studies but also has been applied to a wide range of topics and fields that no one could possibly have envisioned 30 years ago. My message is simple: phylogenies are fundamental to comparative biology, but they are not the be-all and end-all. Phylogenies are powerful tools for understanding the past, but like any tool, they have their limitations. In addition, phylogenies are much more informative about pattern than they are about process. The best way to fully understand the past-both pattern and process-is to integrate phylogenies with other types of historical data as well as with direct studies of evolutionary process.

  15. Addressing the unequal geographic distribution of specialist doctors in indonesia: the role of the private sector and effectiveness of current regulations.

    PubMed

    Meliala, Andreasta; Hort, Krishna; Trisnantoro, Laksono

    2013-04-01

    As in many countries, the geographic distribution of the health workforce in Indonesia is unequal, with a concentration in urban and more developed areas, and a scarcity in rural and remote areas. There is less information on the distribution of specialist doctors, yet inequalities in their distribution could compromise efforts to achieve universal coverage by 2014. This paper uses data from 2007 and 2008 to describe the geographic distribution of specialist doctors in Indonesia, and to examine two key factors that influence the distribution and are targets of current policies: sources of income for specialist doctors, and specialist doctor engagement in private practice. The data demonstrates large differences in the ratio of specialist doctors to population among the provinces of Indonesia, with higher ratios on the provinces of the islands of Java, and much lower ratios on the more remote provinces in eastern Indonesia. Between 65% and 80% of specialist doctors' income derives from private practice in non-state hospitals or private clinics. Despite regulations limiting practice locations to three, most specialists studied in a provincial capital city were working in more than three locations, with some working in up to 7 locations, and spending only a few hours per week in their government hospital practice. Our study demonstrates that the current regulatory policies and financial incentives have not been effective in addressing the maldistribution of specialist doctors in a context of a growing private sector and predominance of doctors' income from private sources. A broader and more integrated policy approach, including more innovative service delivery strategies for rural and remote areas, is recommended.

  16. Limit on flavor-changing neutral currents from a measurement of neutrino-electron elastic scattering

    SciTech Connect

    Krakauer, D.A.; Talaga, R.L. University of Maryland, College Park, Maryland 20742 ); Allen, R.C.; Chen, H.H.; Hausammann, R.; Lee, W.P.; Lu, X.; Mahler, H.J.; Wang, K.C. ); Bowles, T.J.; Burman, R.L.; Carlini, R.D.; Cochran, D.R.F.; Doe, P.J.; Frank, J.S.; Potter, M.E.; Sandberg, V.D. ); Piasetzky, E. )

    1992-02-01

    From a measurement of the absolute cross section in {nu}{sub {ital e}e}{sup {minus}} elastic scattering we have set a limit on flavor-changing neutral currents in the neutrino sector. We find that an off-diagonal, flavor-changing coupling is limited to 1{minus}{ital f}{sub {ital e}{ital e}}{lt}0.35 (90% C.L.).

  17. On-current limitation of high-k gate insulator MOSFETs

    NASA Astrophysics Data System (ADS)

    Shih, Chun-Hsing; Wang, Jhong-Sheng; Chien, Nguyen Dang; Shia, Ruei-Kai

    2012-12-01

    This work explores the limitation of high-k gate insulator on improving the driving currents of MOSFET devices. The use of high-k gate dielectric prevents from the gate tunneling current to have an acceptable equivalent oxide thickness (EOT) in scaled MOSFETs. However, the effectiveness of continued EOT reduction in strengthening gate control is limited strongly by the non-scalability of the quantum effect of inversion layer thickness. Both classical and quantum-mechanical approaches of inversion layer thickness are presented to study the effective gate capacitances and associated on-state drain currents. The enhancements of drain current and gate capacitance generated by high-k gate dielectrics are gradually saturated when a higher permittivity dielectric is applied.

  18. Two-dimensional relativistic space charge limited current flow in the drift space

    SciTech Connect

    Liu, Y. L.; Chen, S. H.; Koh, W. S.; Ang, L. K.

    2014-04-15

    Relativistic two-dimensional (2D) electrostatic (ES) formulations have been derived for studying the steady-state space charge limited (SCL) current flow of a finite width W in a drift space with a gap distance D. The theoretical analyses show that the 2D SCL current density in terms of the 1D SCL current density monotonically increases with D/W, and the theory recovers the 1D classical Child-Langmuir law in the drift space under the approximation of uniform charge density in the transverse direction. A 2D static model has also been constructed to study the dynamical behaviors of the current flow with current density exceeding the SCL current density, and the static theory for evaluating the transmitted current fraction and minimum potential position have been verified by using 2D ES particle-in-cell simulation. The results show the 2D SCL current density is mainly determined by the geometrical effects, but the dynamical behaviors of the current flow are mainly determined by the relativistic effect at the current density exceeding the SCL current density.

  19. Two-dimensional relativistic space charge limited current flow in the drift space

    NASA Astrophysics Data System (ADS)

    Liu, Y. L.; Chen, S. H.; Koh, W. S.; Ang, L. K.

    2014-04-01

    Relativistic two-dimensional (2D) electrostatic (ES) formulations have been derived for studying the steady-state space charge limited (SCL) current flow of a finite width W in a drift space with a gap distance D. The theoretical analyses show that the 2D SCL current density in terms of the 1D SCL current density monotonically increases with D/W, and the theory recovers the 1D classical Child-Langmuir law in the drift space under the approximation of uniform charge density in the transverse direction. A 2D static model has also been constructed to study the dynamical behaviors of the current flow with current density exceeding the SCL current density, and the static theory for evaluating the transmitted current fraction and minimum potential position have been verified by using 2D ES particle-in-cell simulation. The results show the 2D SCL current density is mainly determined by the geometrical effects, but the dynamical behaviors of the current flow are mainly determined by the relativistic effect at the current density exceeding the SCL current density.

  20. The enhancement of edge turbulence in tokamaks by a limiter current

    SciTech Connect

    Nedospasov, A.V. )

    1993-09-01

    The results indicating that enhanced electrostatic potential fluctuations had been observed in the scrape-off layer, due to biasing, were published recently. The qualitative explanation of these experimental results as an effect of current owing to the flute instability with the dissipation into the sheath layer near the surfaces is presented in this paper. The possibility of controlling the edge turbulence by a limiter current is shown.

  1. Surveillance of fetal arrhythmias in the outpatient setting: current limitations and call for action.

    PubMed

    Freire, Grace

    2015-12-01

    Surveillance of fetal arrhythmias in the outpatient setting remains limited by lack of monitoring modalities. Despite technological advances made in the field of obstetrics, existing devices are not currently suitable to monitor fetal arrhythmias. In this report, the author describes the current and developing fetal heart rate monitoring technologies including the recent introduction of hand-held Doppler monitors for outpatient surveillance of fetal arrhythmias.

  2. Superhydrophobic SAM Modified Electrodes for Enhanced Current Limiting Properties in Intrinsic Conducting Polymer Surge Protection Devices.

    PubMed

    Jabarullah, Noor H; Verrelli, Emanuele; Mauldin, Clayton; Navarro, Luis A; Golden, Josh H; Madianos, Leonidas M; Kemp, Neil T

    2015-06-01

    Surface interface engineering using superhydrophobic gold electrodes made with 1-dodecanethiol self-assembled monolayer (SAM) has been used to enhance the current limiting properties of novel surge protection devices based on the intrinsic conducting polymer, polyaniline doped with methanesulfonic acid. The resulting devices show significantly enhanced current limiting characteristics, including current saturation, foldback, and negative differential effects. We show how SAM modification changes the morphology of the polymer film directly adjacent to the electrodes, leading to the formation of an interfacial compact thin film that lowers the contact resistance at the Au-polymer interface. We attribute the enhanced current limiting properties of the devices to a combination of lower contact resistance and increased Joule heating within this interface region which during a current surge produces a current blocking resistive barrier due to a thermally induced dedoping effect caused by the rapid diffusion of moisture away from this region. The effect is exacerbated at higher applied voltages as the higher temperature leads to stronger depletion of charge carriers in this region, resulting in a negative differential resistance effect. PMID:25996202

  3. Superhydrophobic SAM Modified Electrodes for Enhanced Current Limiting Properties in Intrinsic Conducting Polymer Surge Protection Devices.

    PubMed

    Jabarullah, Noor H; Verrelli, Emanuele; Mauldin, Clayton; Navarro, Luis A; Golden, Josh H; Madianos, Leonidas M; Kemp, Neil T

    2015-06-01

    Surface interface engineering using superhydrophobic gold electrodes made with 1-dodecanethiol self-assembled monolayer (SAM) has been used to enhance the current limiting properties of novel surge protection devices based on the intrinsic conducting polymer, polyaniline doped with methanesulfonic acid. The resulting devices show significantly enhanced current limiting characteristics, including current saturation, foldback, and negative differential effects. We show how SAM modification changes the morphology of the polymer film directly adjacent to the electrodes, leading to the formation of an interfacial compact thin film that lowers the contact resistance at the Au-polymer interface. We attribute the enhanced current limiting properties of the devices to a combination of lower contact resistance and increased Joule heating within this interface region which during a current surge produces a current blocking resistive barrier due to a thermally induced dedoping effect caused by the rapid diffusion of moisture away from this region. The effect is exacerbated at higher applied voltages as the higher temperature leads to stronger depletion of charge carriers in this region, resulting in a negative differential resistance effect.

  4. Using a Sequence Homology-Based Predictive Strategy to Address Current Demands for Focused Toxicity Testing in Ecological Risk Assessment

    EPA Science Inventory

    The lack of resources available for comprehensive toxicity testing, international interest in limiting the quantity of animals used in testing, and a mounting list of anthropogenic chemicals produced world-wide have led to the exploration of innovative means for identifying chemi...

  5. Solid-state circuit breaker with current limiting characteristic using a superconducting coil

    DOEpatents

    Boenig, Heinrich J.

    1984-01-01

    A thyristor bridge interposes an ac source and a load. A series connected DC source and superconducting coil within the bridge biases the thyristors thereof so as to permit bidirectional ac current flow therethrough under normal operating conditions. Upon a fault condition a control circuit triggers the thyristors so as to reduce ac current flow therethrough to zero in less than two cycles and to open the bridge thereafter. Upon a temporary overload condition the control circuit triggers the thyristors so as to limit ac current flow therethrough to an acceptable level.

  6. Solid-state circuit breaker with current-limiting characteristic using a superconducting coil

    DOEpatents

    Boenig, H.J.

    1982-08-16

    A thyristor bridge interposes an ac source and a load. A series connected DC source and superconducting coil within the bridge biases the thyristors thereof so as to permit bidirectional ac current flow therethrough under normal operating conditions. Upon a fault condition a control circuit triggers the thyristors so as to reduce ac current flow therethrough to zero in less than two eyeles and to open the bridge thereafter. Upon a temporary overload condition the control circuit triggers the thyristors so as to limit ac current flow therethrough to an acceptable level.

  7. Generalized space-charge limited current and virtual cathode behaviors in one-dimensional drift space

    SciTech Connect

    Yang, Zhanfeng; Liu, Guozhi; Shao, Hao; Chen, Changhua; Sun, Jun

    2013-10-15

    This paper reports the space-charge limited current (SLC) and virtual cathode behaviors in one-dimensional grounded drift space. A simple general analytical solution and an approximate solution for the planar diode are given. Through a semi-analytical method, a general solution for SLC in one-dimensional drift space is obtained. The behaviors of virtual cathode in the drift space, including dominant frequency, electron transit time, position, and transmitted current, are yielded analytically. The relationship between the frequency of the virtual cathode oscillation and the injected current presented may explain previously reported numerical works. Results are significant in facilitating estimations and further analytical studies.

  8. Current-limiting and ultrafast system for the characterization of resistive random access memories.

    PubMed

    Diaz-Fortuny, J; Maestro, M; Martin-Martinez, J; Crespo-Yepes, A; Rodriguez, R; Nafria, M; Aymerich, X

    2016-06-01

    A new system for the ultrafast characterization of resistive switching phenomenon is developed to acquire the current during the Set and Reset process in a microsecond time scale. A new electronic circuit has been developed as a part of the main setup system, which is capable of (i) applying a hardware current limit ranging from nanoampers up to miliampers and (ii) converting the Set and Reset exponential gate current range into an equivalent linear voltage. The complete system setup allows measuring with a microsecond resolution. Some examples demonstrate that, with the developed setup, an in-depth analysis of resistive switching phenomenon and random telegraph noise can be made. PMID:27370480

  9. Current-limiting and ultrafast system for the characterization of resistive random access memories.

    PubMed

    Diaz-Fortuny, J; Maestro, M; Martin-Martinez, J; Crespo-Yepes, A; Rodriguez, R; Nafria, M; Aymerich, X

    2016-06-01

    A new system for the ultrafast characterization of resistive switching phenomenon is developed to acquire the current during the Set and Reset process in a microsecond time scale. A new electronic circuit has been developed as a part of the main setup system, which is capable of (i) applying a hardware current limit ranging from nanoampers up to miliampers and (ii) converting the Set and Reset exponential gate current range into an equivalent linear voltage. The complete system setup allows measuring with a microsecond resolution. Some examples demonstrate that, with the developed setup, an in-depth analysis of resistive switching phenomenon and random telegraph noise can be made.

  10. Current-limiting and ultrafast system for the characterization of resistive random access memories

    NASA Astrophysics Data System (ADS)

    Diaz-Fortuny, J.; Maestro, M.; Martin-Martinez, J.; Crespo-Yepes, A.; Rodriguez, R.; Nafria, M.; Aymerich, X.

    2016-06-01

    A new system for the ultrafast characterization of resistive switching phenomenon is developed to acquire the current during the Set and Reset process in a microsecond time scale. A new electronic circuit has been developed as a part of the main setup system, which is capable of (i) applying a hardware current limit ranging from nanoampers up to miliampers and (ii) converting the Set and Reset exponential gate current range into an equivalent linear voltage. The complete system setup allows measuring with a microsecond resolution. Some examples demonstrate that, with the developed setup, an in-depth analysis of resistive switching phenomenon and random telegraph noise can be made.

  11. Performance and limits of current satellite-only and combined gravity field models (Invited)

    NASA Astrophysics Data System (ADS)

    Pail, R.

    2013-12-01

    During the last decade, the successful operation of the dedicated satellite missions GOCE and GRACE have revolutionized our picture of the Earth's gravity field, because they delivered a static global gravity field map with high and homogeneous accuracy for spatial lengthscales down to 80-100 km. The current satellite-only models of the fourth generation including GOCE data have reached accuracies of about 3 cm in geoid height and less than 1 mGal in gravity anomalies at degree/order 200 (100 km spatial half-wavelength). Due to the attenuation of the gravity field with orbit altitude, gravity field models derived only from satellite data will never be able to achieve very high spatial resolutions of only a few kilometres. However, precise knowledge of the Earth's gravity field structure with very high resolution is essential not only for a range of geoscience disciplines, such as solid Earth geophysics for lithospheric modelling and geological interpretation, exploration geophysics, and several climate research applications such as ocean circulation or sea level change research, but also for geodesy (e.g., surveying, inertial navigation) and civil engineering (e.g., construction, modelling of water flow for hydro-engineering). For this reason, satellite-only models are complemented by combined gravity field models, which contain very high-resolution or even point-wise gravity field information obtained by terrestrial gravity measurements over continents, and satellite altimetry over the oceans. To further increase the spatial resolution beyond 10-20 km, measured terrestrial and satellite data can also be augmented by high-resolution gravity field signals synthesized from topographic models, although the latter is not useful anymore for geophysical interpretation. In this contribution we explore the performance and the limits of the most recent satellite-only and combined Earth's gravity field models. On the basis of selected case studies from different

  12. Application Study of a High Temperature Superconducting Fault Current Limiter for Electric Power System

    NASA Astrophysics Data System (ADS)

    Naito, Yuji; Shimizu, Iwao; Yamaguchi, Iwao; Kaiho, Katsuyuki; Yanabu, Satoru

    Using high temperature superconductor, a Superconducting Fault Current Limiter (SFCL) was made and tested. Superconductor and vacuum interrupter as commutation switch are connected in parallel with bypass coil. When a fault occurs and the excessive current flows, superconductor is first quenched and the current is transferred to bypass coil because on voltage drop of superconductor. At the same time, since magnetic field is generated by current which flows in bypass coil, commutation switch is immediately driven by electromagnetic repulsion plate connected to driving rod of vacuum interrupter, and superconductor is separated from this circuit. Using the testing model, we could separate the superconductor from a circuit due to movement of vacuum interrupter within half-cycle current and transfer all current to bypass coil. Since operation of a commutation switch is included in current limiting operation of this testing model, it is one of helpful circuit of development of SFCL in the future. Moreover, since it can make the consumed energy of superconductor small during fault state due to realization of high-speed switch with simple composition, the burden of superconductor is reduced compared with conventional resistive type SFCL and it is considered that the flexibility of a SFCL design increases. Cooperation with a circuit breaker was also considered, the trial calculation of a parameter and energy of operation is conducted and discussion in the case of installing the SFCL to electric power system is made.

  13. Survey of Current Practices in the Psychological Assessment of Limited-English-Proficiency Handicapped Children.

    ERIC Educational Resources Information Center

    Nuttall, Ena Vazquez

    1987-01-01

    Discusses current psychological and educational assessment practices used with elementary school limited-English proficiency (LEP) children, as revealed by a nationwide study of local education agencies (LEAs) (n=21) that had LEP handicapped children mainstreamed in bilingual education classrooms. Testing approaches most frequently used with LEP…

  14. 40 CFR 450.21 - Effluent limitations reflecting the best practicable technology currently available (BPT).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... stormwater volume and velocity within the site to minimize soil erosion; (2) Control stormwater discharges... downstream channel and streambank erosion; (3) Minimize the amount of soil exposed during construction... limitations reflecting the best practicable technology currently available (BPT). Except as provided in 40...

  15. 40 CFR 450.21 - Effluent limitations reflecting the best practicable technology currently available (BPT).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... stormwater volume and velocity within the site to minimize soil erosion; (2) Control stormwater discharges... downstream channel and streambank erosion; (3) Minimize the amount of soil exposed during construction... limitations reflecting the best practicable technology currently available (BPT). Except as provided in 40...

  16. Low-Aspect Tokamak Start-Up and Operational Current Limits in Cdx-U

    NASA Astrophysics Data System (ADS)

    Jones, Theodore George

    1995-01-01

    A new, small, low-aspect-ratio tokamak (LART), named the Current Drive Experiment-Upgrade (CDX-U), has been designed and built for the investigation and development of the LART configuration, as well as for the investigation of novel current drive methods. Recently, an inductive ohmic heating and current drive (OH) system, including a compact high-field OH transformer coil, was designed and installed in CDX-U, enabling the study of LART plasmas with higher plasma currents and temperatures. Electron cyclotron resonance heating (ECH) was used in CDX-U to assist plasma breakdown, allowing breakdown with low initial induced voltage. Plasma start-up was achieved with transmitted ECH power of approximately l% of the maximum coupled OH power, at loop voltages as low as 1 Volt, and in toroidal magnetic fields ranging by a factor of 2.5 in strength. The reduction in loop voltage necessary for start-up minimized large, induced eddy currents in the toroidally continuous vessel walls common to LARTs. Plasma start-up and control in the presence of these significant vessel eddy currents was demonstrated, an important achievement for LART operation. Calculated ohmic efficiency, in terms of the Ejima coefficient. C_{E} , compared favorably with that found in other tokamaks, yielding C_{E} >=q 0.3-0.4. An operational current limit was found during extensive CDX-U ohmic operation, corresponding to an MHD safety factor, q(a), of approximately 3.5, a new low demonstrated q-limit for an aspect ratio, A, of 1.6. Studies of magnetic fluctuations in a range of plasma current from 15 kA to 40 kA revealed a coherent, saturating, 10-15 kHz frequency mode, with a toroidal mode number of n = l and a poloidol mode number ranging from m = 1 to m = 3. Numerical stability analysis of a magnetic reconstruction of a typical discharge exhibiting this mode indicated ideal stability. Previous studies of this mode at the lower plasma currents showed the amplitude increasing dramatically as the safety

  17. Current-limited imposed-potential technique for inducing and monitoring metastable pitting events

    SciTech Connect

    Wall, F.D.

    1999-11-24

    A technique has been developed to selectively induce metastable pitting while preventing the transition to stable pit growth. The current-limited imposed-potential (CLIP) technique limits available cathodic current to an initiated site using a resistor in series with the working electrode to form a voltage divider. Potentiodynamic CLIP testing yields a distribution of breakdown potentials from a single experiment. Potentiostatic CLIP testing yields induction time data, which can be used as input to a calculation of germination rate. Initial data indicate that a one-to-one correlation exists between electrochemical transients and observed pitting sites. The CLIP technique provides a consistent means of gathering quantitative potential and current transients associated with localized oxide breakdown.

  18. Solid-State Fault Current Limiter Development : Design and Testing Update of a 15kV SSCL Power Stack

    SciTech Connect

    Dr. Ram Adapa; Mr. Dante Piccone

    2012-04-30

    ABSTRACT The Solid-State Fault Current Limiter (SSCL) is a promising technology that can be applied to utility power delivery systems to address the problem of increasing fault currents associated with load growth. As demand continues to grow, more power is added to utility system either by increasing generator capacity or by adding distributed generators, resulting in higher available fault currents, often beyond the capabilities of the present infrastructure. The SSCL is power-electronics based equipment designed to work with the present utility system to address this problem. The SSCL monitors the line current and dynamically inserts additional impedance into the line in the event of a fault being detected. The SSCL is based on a modular design and can be configured for 5kV through 69kV systems at nominal current ratings of 1000A to 4000A. Results and Findings This report provides the final test results on the development of 15kV class SSCL single phase power stack. The scope of work included the design of the modular standard building block sub-assemblies, the design and manufacture of the power stack and the testing of the power stack for the key functional tests of continuous current capability and fault current limiting action. Challenges and Objectives Solid-State Current Limiter technology impacts a wide spectrum of utility engineering and operating personnel. It addresses the problems associated with load growth both at Transmission and Distribution class networks. The design concept is pioneering in terms of developing the most efficient and compact power electronics equipment for utility use. The initial test results of the standard building blocks are promising. The independent laboratory tests of the power stack are promising. However the complete 3 phase system needs rigorous testing for performance and reliability. Applications, Values, and Use The SSCL is an intelligent power-electronics device which is modular in design and can provide current

  19. Space-charge-limited currents for cathodes with electric field enhanced geometry

    NASA Astrophysics Data System (ADS)

    Lai, Dingguo; Qiu, Mengtong; Xu, Qifu; Huang, Zhongliang

    2016-08-01

    This paper presents the approximate analytic solutions of current density for annulus and circle cathodes. The current densities of annulus and circle cathodes are derived approximately from first principles, which are in agreement with simulation results. The large scaling laws can predict current densities of high current vacuum diodes including annulus and circle cathodes in practical applications. In order to discuss the relationship between current density and electric field on cathode surface, the existing analytical solutions of currents for concentric cylinder and sphere diodes are fitted from existing solutions relating with electric field enhancement factors. It is found that the space-charge-limited current density for the cathode with electric-field enhanced geometry can be written in a general form of J = g(βE)2J0, where J0 is the classical (1D) Child-Langmuir current density, βE is the electric field enhancement factor, and g is the geometrical correction factor depending on the cathode geometry.

  20. Predicting the behavioral impact of transcranial direct current stimulation: issues and limitations

    PubMed Central

    de Berker, Archy O.; Bikson, Marom; Bestmann, Sven

    2013-01-01

    The transcranial application of weak currents to the human brain has enjoyed a decade of widespread use, providing a simple and powerful tool for non-invasively altering human brain function. However, our understanding of current delivery and its impact upon neural circuitry leaves much to be desired. We argue that the credibility of conclusions drawn with transcranial direct current stimulation (tDCS) is contingent upon realistic explanations of how tDCS works, and that our present understanding of tDCS limits the technique’s use to localize function in the human brain. We outline two central issues where progress is required: the localization of currents, and predicting their functional consequence. We encourage experimenters to eschew simplistic explanations of mechanisms of transcranial current stimulation. We suggest the use of individualized current modeling, together with computational neurostimulation to inform mechanistic frameworks in which to interpret the physiological impact of tDCS. We hope that through mechanistically richer descriptions of current flow and action, insight into the biological processes by which transcranial currents influence behavior can be gained, leading to more effective stimulation protocols and empowering conclusions drawn with tDCS. PMID:24109445

  1. The effectiveness of health appraisal processes currently in addressing health and wellbeing during spatial plan appraisal: a systematic review

    PubMed Central

    2011-01-01

    Background Spatial planning affects the built environment, which in turn has the potential to have a significant impact on health, for good or ill. One way of ensuring that spatial plans take due account of health is through the inclusion of health considerations in the statutory and non statutory appraisal processes linked to plan-making processes. Methods A systematic review to identify evaluation studies of appraisals or assessments of plans where health issues were considered from 1987 to 2010. Results A total of 6161 citations were identified: 6069 from electronic databases, 57 fromwebsite searches, with a further 35 citations from grey literature, of which 20 met the inclusion criteria. These 20 citations reported on a total of 135 different case studies: 11 UK HIA; 11 non UK high income countries HIA, 5 UK SEA or other integrated appraisal; 108 non UK high income SEA or other integrated appraisal. All studies were in English. No relevant studies were identified reporting on low or middle income countries. The studies were limited by potential bias (no independent evaluation, with those undertaking the appraisal also responsible for reporting outcomes), lack of detail and a lack of triangulation of results. Health impact assessments generally covered the four specified health domains (physical activity, mental health and wellbeing, environmental health issues such as pollution and noise, injury) more comprehensively than SEA or other integrated appraisals, although mental health and wellbeing was an underdeveloped area. There was no evidence available on the incorporation of health in Sustainability Appraisal, limited evidence that the recommendations from any type of appraisal were implemented, and almost no evidence that the recommendations had led to the anticipated outcomes or improvements in health postulated. Conclusion Research is needed to assess (i) the degree to which statutory plan appraisal processes (SA in the UK) incorporate health; (ii) whether

  2. Application of active quenching of second generation wire for current limiting

    DOE PAGES

    Solovyov, Vyacheslav F.; Li, Qiang

    2015-10-19

    Superconducting fault current limiters (SFCL's) are increasingly implemented in the power grid as a protection of substation equipment from fault currents. Resistive SFCL's are compact and light, however they are passively triggered and thus may not be sufficiently sensitive to respond to faults in the distribution grid. Here, we explore the prospect of adding an active management feature to a traditional resistive SFCL. A flexible radio-frequency coil, which is an integral part of the switching structure, acts as a triggering device. We show that the application of a short, 10 ms, burst of ac magnetic field during the fault triggersmore » a uniform quench of the wire and significantly reduces the reaction time of the wire at low currents. The ac field burst generates a high density of normal zones, which merge into a continuous resistive region at a rate much faster than that of sparse normal zones created by the transport current alone.« less

  3. Application of active quenching of second generation wire for current limiting

    SciTech Connect

    Solovyov, Vyacheslav F.; Li, Qiang

    2015-10-19

    Superconducting fault current limiters (SFCL's) are increasingly implemented in the power grid as a protection of substation equipment from fault currents. Resistive SFCL's are compact and light, however they are passively triggered and thus may not be sufficiently sensitive to respond to faults in the distribution grid. Here, we explore the prospect of adding an active management feature to a traditional resistive SFCL. A flexible radio-frequency coil, which is an integral part of the switching structure, acts as a triggering device. We show that the application of a short, 10 ms, burst of ac magnetic field during the fault triggers a uniform quench of the wire and significantly reduces the reaction time of the wire at low currents. The ac field burst generates a high density of normal zones, which merge into a continuous resistive region at a rate much faster than that of sparse normal zones created by the transport current alone.

  4. Reversible stress and strain limits of the critical current of practical REBCO and BSCCO wires

    NASA Astrophysics Data System (ADS)

    Osamura, K.; Machiya, S.; Nishijima, G.

    2016-09-01

    Practical REBCO and BSCCO-2223 tape-shaped wires are now manufactured on an industrial scale. They are a typical composite material consisting of superconducting layer/filaments together with functional components. These functional components affect directly the stress and strain dependences of the critical current. When applying an external stress R, the critical current I c was measured. Then the external stress was reduced to R = 0 and the recovered critical current I cr was again measured. The tensile stress and strain dependences of both normalized critical currents divided by the original value, I c/I c0 and I cr/I c0 were investigated. In general I cr/I c0 recovered close to unity when the applied stress was low, but its recovering level decreased gradually with increasing applied stress. The definition of the reversible stress and strain limits was investigated and its validity was proved using the cyclic loading test. The original definition of reversible stress and strain limits of critical current relates to: (1) when releasing the applied stress and strain, the I c shall recover to the original value, and (2) when applying the cyclic stresses, the I c shall keep the original value. Here, as a practical definition for the reversible stress and strain limits, the tensile stress and strain at 99% recovery of I c have been proposed. On the other hand, it was made clear that the stress and strain at I c 95% retention are not valid for use commonly as a criterion of reversible stress and strain limits for both practical REBCO and BSCCO-2223 wires.

  5. Metabolic modeling of spatial heterogeneity of biofilms in microbial fuel cells reveals substrate limitations in electrical current generation.

    PubMed

    Jayasinghe, Nadeera; Franks, Ashley; Nevin, Kelly P; Mahadevan, Radhakrishnan

    2014-10-01

    Microbial fuel cells (MFCs) have been proposed as an alternative energy resource for the conversion of organic compounds to electricity. In an MFC, microorganisms such as Geobacter sulfurreducens form an anode-associated biofilm that can completely oxidize organic matter (electron donor) to carbon dioxide with direct electron transfer to the anode (electron acceptor). Mathematical models are useful in analyzing biofilm processes; however, existing models rely on Nernst-Monod type expressions, and evaluate extracellular processes separated from the intracellular metabolism of the microorganism. Thus, models that combine both extracellular and intracellular components, while addressing spatial heterogeneity, are essential for improved representation of biofilm processes. The goal of this work is to develop a model that integrates genome-scale metabolic models with the model of biofilm environment. This integrated model shows the variations of electrical current production and biofilm thickness under the presence/absence of NH4 in the bulk solution, and under varying maintenance energy demands. Further, sensitivity analysis suggested that conductivity is not limiting electrical current generation and that increasing cell density can lead to enhanced current generation. In addition, the modeling results also highlight instances such as the transformation into respiring cells, where the mechanism of electrical current generation during biofilm development is not yet clearly understood.

  6. Individually addressable multi-chamber electroporation platform with dielectrophoresis and alternating-current-electro-osmosis assisted cell positioning

    PubMed Central

    Park, Sinwook; Bassat, Dana Ben; Yossifon, Gilad

    2014-01-01

    A multi-functional microfluidic platform was fabricated to demonstrate the feasibility of on-chip electroporation integrated with dielectrophoresis (DEP) and alternating-current-electro-osmosis (ACEO) assisted cell/particle manipulation. A spatial gradient of electroporation parameters was generated within a microchamber array and validated using normal human dermal fibroblast (NHDF) cells and red fluorescent protein-expressing human umbilical vein endothelial cells (RFP-HUVECs) with various fluorescent indicators. The edge of the bottom electrode, coinciding with the microchamber entrance, may act as an on-demand gate, functioning under either positive or negative DEP. In addition, at sufficiently low activation frequencies, ACEO vortices can complement the DEP to contribute to a rapid trapping/alignment of particles. As such, results clearly indicate that the microfluidic platform has the potential to achieve high-throughput screening for electroporation with spatial control and uniformity, assisted by DEP and ACEO manipulation/trapping of particles/cells into individual microchambers. PMID:24803966

  7. A superconducting fault current limiter integrated in the cold heat exchanger of a thermoacoustic refrigerator

    NASA Astrophysics Data System (ADS)

    Osorio, M. R.; Bétrancourt, A.; François, M. X.; Veira, J. A.; Vidal, F.

    2008-09-01

    In this work we probe a compact superconducting fault current limiter (SFCL) integrated in the cold heat exchanger of a thermoacoustic refrigerator. A design for an SFCL device with a power of about 2.2 kW is presented and described in detail. A thermoacoustic refrigerator is also proposed which, under fault conditions, must be able to remove around 50 W at 80 K. A simulation routine is run to test the performance of the SFCL, based on YBCO films, in terms of both the limiting capacity and the energy to be dissipated and removed inside the heat exchanger.

  8. Resource needs for addressing noncommunicable disease in low- and middle-income countries: current and future developments.

    PubMed

    Stenberg, Karin; Chisholm, Dan

    2012-03-01

    Low and middle income countries are faced with a range of challenges related to providing efficient and affordable health care. With non-communicable diseases (NCD) on the rise, there is a growing need to be able to estimate resource requirements, costs and expected impact associated with various investment strategies related to prevention and control of NCD. In this article, recently developed costing and health impact models for non-communicable disease are reviewed, with a view to drawing out their main findings as well as methodological limitations. A key shortcoming is that earlier modelling efforts have taken a vertical approach to costing, when in reality a more integrated, horizontal approach is needed in order to effectively plan for scaled-up investment and system development. We subsequently describe how the integration of an NCD module into the joint United Nations OneHealth tool will enable low- and middle-income countries to bring NCD into an integrated process for national strategic health planning.

  9. Computational Study on the Steady-state Impedance of Saturated-core Superconducting Fault Current Limiter

    NASA Astrophysics Data System (ADS)

    Zhang, C.; Tang, Y.; Liang, S.; Ren, L.; Wang, Z.; Xu, Y.

    This paper presents the electromagnetic analysis of a high voltage saturated-core superconducting fault current limiter (SCSFCL). The numerical analyses of a three-dimensional (3D) model is shown, and the specific parameters are given. The model focus on the steady-state impedance of the limiter when connected to the power grid. It analyzed the dependence of steady-state impedance on the AC coil current, and the relationship between oil gap and coil inductance. The results suggest that, adding oil gap between slice of silicon steel can reduce the core cross-section, restrain the ultraharmonic and decrease the steady-state impedance. As the core cross-section of AC limb decreased from 4344 cm2 to 3983 cm2, the total harmonic distortion for voltage decreased from 2.4% to 1.8%, and the impedance decreased from 1.082 Ω to 1.069 Ω(Idc=400A,Iac=1296A).

  10. Limiting diffusion current at rotating disk electrode with dense particle layer.

    PubMed

    Weroński, P; Nosek, M; Batys, P

    2013-09-28

    Exploiting the concept of diffusion permeability of multilayer gel membrane and porous multilayer we have derived a simple analytical equation for the limiting diffusion current at rotating disk electrode (RDE) covered by a thin layer with variable tortuosity and porosity, under the assumption of negligible convection in the porous film. The variation of limiting diffusion current with the porosity and tortuosity of the film can be described in terms of the equivalent thickness of stagnant solution layer, i.e., the average ratio of squared tortuosity to porosity. In case of monolayer of monodisperse spherical particles, the equivalent layer thickness is an algebraic function of the surface coverage. Thus, by means of cyclic voltammetry of RDE with a deposited particle monolayer we can determine the monolayer surface coverage. The effect of particle layer adsorbed on the surface of RDE increases non-linearly with surface coverage. We have tested our theoretical results experimentally by means of cyclic voltammetry measurements of limiting diffusion current at the glassy carbon RDE covered with a monolayer of 3 μm silica particles. The theoretical and experimental results are in a good agreement at the surface coverage higher than 0.7. This result suggests that convection in a monolayer of 3 μm monodisperse spherical particles is negligibly small, in the context of the coverage determination, in the range of very dense particle layers. PMID:24089793

  11. Exploring Ivorian perspectives on the effectiveness of the current Ivorian science curriculum in addressing issues related to HIV/AIDS

    NASA Astrophysics Data System (ADS)

    Ado, Gustave Firmin

    School-based HIV/AIDS science education has the potential to impact students when integrated into the science curriculum. However, this mixed method study shows that school-based HIV/AIDS science education is often not infused into career subjects such as science education but integrated into civics education and taught by teachers who lack the skills, knowledge, and the training in the delivery of effective school HIV/AIDS education. Since science is where biological events take place, it is suggested that HIV/AIDS science merits being taught in the science education classroom. This study took place in nine public middle schools within two school districts in Abidjan, Ivory Coast, one major urban city in the southern region. The study utilized triangulation of multiple data sources---both qualitative and quantitative. To substantiate the claims made in this study, a range of qualitative methods such as field notes and individual interviews with 39 teachers, 63 sixth grade students, 8 school administrators, and 20 community elders were used. For the quantitative portion 140 teachers and 3510 sixth grade students were surveyed. The findings from the study prioritize science education that includes HIV/AIDS science education for all, with emphasis on HIV/AIDS prevention in Ivory Coast. The factors that influence the implementation of HIV/AIDS curricula within the Ivorian sixth grade classrooms are discussed. Interview and survey data from students, teachers, school administrators, and community elders indicate that in the Ivorian school setting, "gerontocratic" cultural influences, religious beliefs, personal cultural beliefs, and time spent toward the discourse on HIV/AIDS have led to HIV/AIDS education that is often insufficient to change either misconceptions about HIV/AIDS or risky practices. It was also found that approaches to teaching HIV/AIDS does not connect with youth cultures. By reframing and integrating current HIV/AIDS curricula into the science

  12. Operation Tests for SN Transition Superconducting Fault Current Limiter in the Power System Simulator

    NASA Astrophysics Data System (ADS)

    Kameda, Hideyuki; Torii, Shinji; Kumano, Teruhisa; Sakaki, Hisayoshi; Kubota, Hiroshi; Yasuda, Kenji

    One of important problems to be solved in Japanese trunk transmission systems is the reduction of short circuit capacity. As this countermeasure, double buses are split into two buses in some substations. In recent years, dispersed generators are introduced in lower voltage classes due to the introduction of the electricity deregulation. In such a distribution system as many dispersed generators are introduced, it is a possibility that the fault current becomes beyond the breaking capacity at the occurrence of short circuit. Introduction of superconducting fault current limiters into a power system is very effective as one of the means to solve the above-mentioned problem, and we have studied on the effective introduction method of them and setting method of their parameters. This paper describes the results of the operation tests for SN transition type of a superconducting fault current limiter using 3 phases of FCL modules against various kinds of system faults or inrush current in the Power System Simulator installed at CRIEPI.

  13. Theory of space-charge-limited ballistic currents in nanostructures of different dimensionalities

    SciTech Connect

    Beznogov, M. V. Suris, R. A.

    2013-04-15

    A new unified approach to the description of ballistic unipolar-injection currents is proposed for nanostructures of different dimensionalities. It is shown that in the case of three-dimensional (3D), two-dimensional (2D), and one-dimensional (1D) structures the problem can be reduced to a nonlinear integral equation with a dimensionless parameter determining the coefficient of the universal current-voltage characteristic. The existence of a maximum for this parameter, which is analogous to the Bursian limit for a vacuum diode, is proven for each dimensionality. The current-voltage characteristics and the potential and charge distributions are calculated for 3D, 2D, and 1D structures.

  14. A Limited In-Flight Evaluation of the Constant Current Loop Strain Measurement Method

    NASA Technical Reports Server (NTRS)

    Olney, Candida D.; Collura, Joseph V.

    1997-01-01

    For many years, the Wheatstone bridge has been used successfully to measure electrical resistance and changes in that resistance. However, the inherent problem of varying lead wire resistance can cause errors when the Wheatstone bridge is used to measure strain in a flight environment. The constant current loop signal-conditioning card was developed to overcome that difficulty. This paper describes a limited evaluation of the constant current loop strain measurement method as used in the F-16XL ship 2 Supersonic Laminar Flow Control flight project. Several identical strain gages were installed in close proximity on a shock fence which was mounted under the left wing of the F- 1 6XL ship 2. Two strain gage bridges were configured using the constant current loop, and two were configured using the Wheatstone bridge circuitry. Flight data comparing the output from the constant current loop configured gages to that of the Wheatstone bridges with respect to signal output, error, and noise are given. Results indicate that the constant current loop strain measurement method enables an increased output, unaffected by lead wire resistance variations, to be obtained from strain gages.

  15. Current strategies for improving access and adherence to antiretroviral therapies in resource-limited settings

    PubMed Central

    Scanlon, Michael L; Vreeman, Rachel C

    2013-01-01

    The rollout of antiretroviral therapy (ART) significantly reduced human immunodeficiency virus (HIV)-related morbidity and mortality, but good clinical outcomes depend on access and adherence to treatment. In resource-limited settings, where over 90% of the world’s HIV-infected population resides, data on barriers to treatment are emerging that contribute to low rates of uptake in HIV testing, linkage to and retention in HIV care systems, and suboptimal adherence rates to therapy. A review of the literature reveals limited evidence to inform strategies to improve access and adherence with the majority of studies from sub-Saharan Africa. Data from observational studies and randomized controlled trials support home-based, mobile and antenatal care HIV testing, task-shifting from doctor-based to nurse-based and lower level provider care, and adherence support through education, counseling and mobile phone messaging services. Strategies with more limited evidence include targeted HIV testing for couples and family members of ART patients, decentralization of HIV care, including through home- and community-based ART programs, and adherence promotion through peer health workers, treatment supporters, and directly observed therapy. There is little evidence for improving access and adherence among vulnerable groups such as women, children and adolescents, and other high-risk populations and for addressing major barriers. Overall, studies are few in number and suffer from methodological issues. Recommendations for further research include health information technology, social-level factors like HIV stigma, and new research directions in cost-effectiveness, operations, and implementation. Findings from this review make a compelling case for more data to guide strategies to improve access and adherence to treatment in resource-limited settings. PMID:23326204

  16. Status of high temperature superconductor cable and fault current limiter projects at American Superconductor

    NASA Astrophysics Data System (ADS)

    Maguire, J. F.; Yuan, J.

    2009-10-01

    This paper will describe the status of three key programs currently underway at American Superconductor Corp. The first program is the LIPA project which is a transmission voltage high temperature superconducting cable program, with funding support from the US Department of Energy. The 600 m cable, capable of carrying 574 MVA, was successfully installed and commissioned in LIPA grid on April 22, 2008. An overview of the project, system level design details and operational data will be provided. In addition, the status of the newly awarded LIPA II project will be described. The second program is Project Hydra, with funding support from the US Department of Homeland Security, to design, develop and demonstrate an HTS cable with fault current limiting functionality. The cable is 300 m long and is being designed to carry 96 MVA at a distribution level voltage of 13.8 kV. The cable will be permanently installed and energized in Manhattan, New York in 2010. The initial status of Project Hydra will be presented. The final program to be discussed is a transmission voltage, high temperature superconducting fault current limiter funded by the US DOE. The project encompasses the design, construction and test of a 115 kV FCL for power transmission within a time frame of 4-5 years. Installation and testing are planned for a Southern California Edison substation. A project overview and progress under the first phase will be reported.

  17. Coil in coil - components for the high voltage superconducting resistive current limiter CULT 110

    NASA Astrophysics Data System (ADS)

    Elschner, S.; Stemmle, M.; Breuer, F.; Walter, H.; Frohne, C.; Noe, M.; Bock, J.

    2008-02-01

    The German government (BMBF/VDI) funded project CULT 110 is presently the largest European current limiter project and aims at the development of a one-phase resistive limiter for the voltage level of 110 kV. The contribution presents the actual state of development of the superconducting components. As in the successful predecessor project CURL 10 these are made of melt cast processed BSCCO 2212 bulk material, however monofilar instead of bifilar coils are used. The electrical protection concept is based on a normal conducting coil arranged around a superconducting coil and connected in parallel. Simultaneously this coil serves as an electrical bypass and, under fault conditions, generates a magnetic field for quench homogenisation. Since no continuously connected shunt is needed, a much higher voltage during faults can be applied. The rules for an optimum superconductor and coil design are given and the viability of the whole concept is demonstrated by both, experiment and numerical simulation.

  18. Extracting electrode space charge limited current: Charge injection into conjugated polyelectrolytes with a semiconductor electrode

    NASA Astrophysics Data System (ADS)

    Walker, Ethan M.; Lonergan, Mark C.

    2016-05-01

    Conjugated polyelectrolytes and related mixed ionic-electronic conductors (MIECs) are being explored for energy applications including solid-state lighting and photovoltaics. Fundamental models of charge injection into MIECs have been primarily developed for MIECs contacted with highly conductive or metal electrodes (MEs), despite many potential applications involving semiconductors. We theoretically and experimentally demonstrate that an appropriate semiconductor electrode (SE), n-type for electron or p-type of hole injection, can limit injection into MIECs. When the SE is the injecting electrode and is under accumulation, there is little difference from a ME. When the SE acts as the extracting electrode, however, injection into the MIEC can be limited because a fraction of any applied bias must support charge depletion in the semiconductor rather than charge injection into the MIEC. In a ME/MIEC/SE system, this can lead to significant asymmetry in current-voltage and injected charge-voltage behavior.

  19. Duration Limits for Orbital Flight: Current Considerations for the International Space Station

    NASA Technical Reports Server (NTRS)

    Smith, Gwen; Sipes, Walter; Duncan, J. Michael; Volpe, Tara; Sargsyan, Ashot E.; Armstrong, Cheryl; Damann, Volker; Castrucci, Filippo; Comtois, Jean-Marc; Tachibana, Shoichi

    2007-01-01

    According to ISS documentation, long-duration missions are defined as missions exceeding 30 days. The ISS medical organization has set a 180-day limit for ISS missions from a medical perspective, with a possibility of planning missions of up to 220days with additional consideration. The ISS medical community does not currently consider changes to the existing duration constraints for ISS mission planning. However, longer stays on orbit may be highly desirable or even necessary in certain foreseeable operational circumstances. To develop a methodology for contingency planning, the ISS medical community, led by NASA, has identified medically relevant risks associated with extended stays of crewmembers aboard the ISS.

  20. Design, Test and Demonstration of Saturable Reactor High-Temperature Superconductor Fault Current Limiters

    SciTech Connect

    Darmann, Frank; Lombaerde, Robert; Moriconi, Franco; Nelson, Albert

    2012-03-01

    Zenergy Power has successfully designed, built, tested, and installed in the US electrical grid a saturable reactor Fault Current Limiter. Beginning in 2007, first as SC Power Systems and from 2008 as Zenergy Power, Inc., ZP used DOE matching grant and ARRA funds to help refine the design of the saturated reactor fault current limiter. ZP ultimately perfected the design of the saturated reactor FCL to the point that ZP could reliably design a suitable FCL for most utility applications. Beginning with a very basic FCL design using 1G HTS for a coil housed in a LN2 cryostat for the DC bias magnet, the technology progressed to a commercial system that was offered for sale internationally. Substantial progress was made in two areas. First, the cryogenics cooling system progressed from a sub-cooled liquid nitrogen container housing the HTS coils to cryostats utilizing dry conduction cooling and reaching temperatures down to less than 20 degrees K. Large, round cryostats with warm bore diameters of 1.7 meters enabled the design of large tanks to hold the AC components. Second, the design of the AC part of the FCL was refined from a six legged spider design to a more compact and lighter design with better fault current limiting capability. Further refinement of the flux path and core shape led to an efficient saturated reactor design requiring less Ampere-turns to saturate the core. In conclusion, the development of the saturable reactor FCL led to a more efficient design not requiring HTS magnets and their associated peripheral equipment, which yielded a more economical product in line with the electric utility industry expectations. The original goal for the DOE funding of the ZP project Design, Test and Demonstration of Saturable Reactor High-Temperature Superconductor Fault Current Limiters was to stimulate the HTS wire industry with, first 1G, then 2G, HTS wire applications. Over the approximately 5 years of ZP's product development program, the amount of HTS wire

  1. Opportunities to overcome the current limitations and challenges for efficient microbial production of optically pure lactic acid.

    PubMed

    Abdel-Rahman, Mohamed Ali; Sonomoto, Kenji

    2016-10-20

    There has been growing interest in the microbial production of optically pure lactic acid due to the increased demand for lactic acid-derived environmentally friendly products, for example biodegradable plastic (poly-lactic acid), as an alternative to petroleum-derived materials. To maximize the market uptake of these products, their cost should be competitive and this could be achieved by decreasing the production cost of the raw material, that is, lactic acid. It is of great importance to isolate and develop robust and highly efficient microbial lactic acid producers. Alongside the fermentative substrate and concentration, the yield and productivity of lactic acid are key parameters and major factors in determining the final production cost of lactic acid. In this review, we will discuss the current limitations and challenges for cost-efficient microbial production of optically pure lactic acid. The main obstacles to effective fermentation are the use of food resources, indirect utilization of polymeric sugars, sensitivity to inhibitory compounds released during biomass treatments, substrate inhibition, decreased lactic acid yield and productivity, inefficient utilization of mixed sugars, end product inhibition, increased use of neutralizing agents, contamination problems, and decreased optical purity of lactic acid. Furthermore, opportunities to address and overcome these limitations, either by fermentation technology or metabolic engineering approaches, will be introduced and discussed.

  2. Opportunities to overcome the current limitations and challenges for efficient microbial production of optically pure lactic acid.

    PubMed

    Abdel-Rahman, Mohamed Ali; Sonomoto, Kenji

    2016-10-20

    There has been growing interest in the microbial production of optically pure lactic acid due to the increased demand for lactic acid-derived environmentally friendly products, for example biodegradable plastic (poly-lactic acid), as an alternative to petroleum-derived materials. To maximize the market uptake of these products, their cost should be competitive and this could be achieved by decreasing the production cost of the raw material, that is, lactic acid. It is of great importance to isolate and develop robust and highly efficient microbial lactic acid producers. Alongside the fermentative substrate and concentration, the yield and productivity of lactic acid are key parameters and major factors in determining the final production cost of lactic acid. In this review, we will discuss the current limitations and challenges for cost-efficient microbial production of optically pure lactic acid. The main obstacles to effective fermentation are the use of food resources, indirect utilization of polymeric sugars, sensitivity to inhibitory compounds released during biomass treatments, substrate inhibition, decreased lactic acid yield and productivity, inefficient utilization of mixed sugars, end product inhibition, increased use of neutralizing agents, contamination problems, and decreased optical purity of lactic acid. Furthermore, opportunities to address and overcome these limitations, either by fermentation technology or metabolic engineering approaches, will be introduced and discussed. PMID:27527396

  3. Limiter

    DOEpatents

    Cohen, S.A.; Hosea, J.C.; Timberlake, J.R.

    1984-10-19

    A limiter with a specially contoured front face is provided. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution. This limiter shape accommodates the various power scrape-off distances lambda p, which depend on the parallel velocity, V/sub parallel/, of the impacting particles.

  4. Does oxygen limit thermal tolerance in arthropods? A critical review of current evidence

    PubMed Central

    Verberk, Wilco C.E.P.; Overgaard, Johannes; Ern, Rasmus; Bayley, Mark; Wang, Tobias; Boardman, Leigh; Terblanche, John S.

    2016-01-01

    Over the last decade, numerous studies have investigated the role of oxygen in setting thermal tolerance in aquatic animals, and there has been particular focus on arthropods. Arthropods comprise one of the most species-rich taxonomic groups on Earth, and display great diversity in the modes of ventilation, circulation, blood oxygen transport, with representatives living both in water (mainly crustaceans) and on land (mainly insects). The oxygen and capacity limitation of thermal tolerance (OCLTT) hypothesis proposes that the temperature dependent performance curve of animals is shaped by the capacity for oxygen delivery in relation to oxygen demand. If correct, oxygen limitation could provide a mechanistic framework to understand and predict both current and future impacts of rapidly changing climate. In arthropods, most studies testing the OCLTT hypothesis have considered tolerance to thermal extremes. These studies likely operate from the philosophical viewpoint that if the model can predict these critical thermal limits, then it is more likely to also explain loss of performance at less extreme, non-lethal temperatures, for which much less data is available. Nevertheless, the extent to which lethal temperatures are influenced by limitations in oxygen supply remains unresolved. Here we critically evaluate the support and universal applicability for oxygen limitation being involved in lethal temperatures in crustaceans and insects. The relatively few studies investigating the OCLTT hypothesis at low temperature do not support a universal role for oxygen in setting the lower thermal limits in arthropods. With respect to upper thermal limits, the evidence supporting OCLTT is stronger for species relying on underwater gas exchange, while the support for OCLTT in air-breathers is weak. Overall, strongest support was found for increased anaerobic metabolism close to thermal maxima. In contrast, there was only mixed support for the prediction that aerobic scope

  5. Does oxygen limit thermal tolerance in arthropods? A critical review of current evidence.

    PubMed

    Verberk, Wilco C E P; Overgaard, Johannes; Ern, Rasmus; Bayley, Mark; Wang, Tobias; Boardman, Leigh; Terblanche, John S

    2016-02-01

    Over the last decade, numerous studies have investigated the role of oxygen in setting thermal tolerance in aquatic animals, and there has been particular focus on arthropods. Arthropods comprise one of the most species-rich taxonomic groups on Earth, and display great diversity in the modes of ventilation, circulation, blood oxygen transport, with representatives living both in water (mainly crustaceans) and on land (mainly insects). The oxygen and capacity limitation of thermal tolerance (OCLTT) hypothesis proposes that the temperature dependent performance curve of animals is shaped by the capacity for oxygen delivery in relation to oxygen demand. If correct, oxygen limitation could provide a mechanistic framework to understand and predict both current and future impacts of rapidly changing climate. In arthropods, most studies testing the OCLTT hypothesis have considered tolerance to thermal extremes. These studies likely operate from the philosophical viewpoint that if the model can predict these critical thermal limits, then it is more likely to also explain loss of performance at less extreme, non-lethal temperatures, for which much less data is available. Nevertheless, the extent to which lethal temperatures are influenced by limitations in oxygen supply remains unresolved. Here we critically evaluate the support and universal applicability for oxygen limitation being involved in lethal temperatures in crustaceans and insects. The relatively few studies investigating the OCLTT hypothesis at low temperature do not support a universal role for oxygen in setting the lower thermal limits in arthropods. With respect to upper thermal limits, the evidence supporting OCLTT is stronger for species relying on underwater gas exchange, while the support for OCLTT in air-breathers is weak. Overall, strongest support was found for increased anaerobic metabolism close to thermal maxima. In contrast, there was only mixed support for the prediction that aerobic scope

  6. Does oxygen limit thermal tolerance in arthropods? A critical review of current evidence.

    PubMed

    Verberk, Wilco C E P; Overgaard, Johannes; Ern, Rasmus; Bayley, Mark; Wang, Tobias; Boardman, Leigh; Terblanche, John S

    2016-02-01

    Over the last decade, numerous studies have investigated the role of oxygen in setting thermal tolerance in aquatic animals, and there has been particular focus on arthropods. Arthropods comprise one of the most species-rich taxonomic groups on Earth, and display great diversity in the modes of ventilation, circulation, blood oxygen transport, with representatives living both in water (mainly crustaceans) and on land (mainly insects). The oxygen and capacity limitation of thermal tolerance (OCLTT) hypothesis proposes that the temperature dependent performance curve of animals is shaped by the capacity for oxygen delivery in relation to oxygen demand. If correct, oxygen limitation could provide a mechanistic framework to understand and predict both current and future impacts of rapidly changing climate. In arthropods, most studies testing the OCLTT hypothesis have considered tolerance to thermal extremes. These studies likely operate from the philosophical viewpoint that if the model can predict these critical thermal limits, then it is more likely to also explain loss of performance at less extreme, non-lethal temperatures, for which much less data is available. Nevertheless, the extent to which lethal temperatures are influenced by limitations in oxygen supply remains unresolved. Here we critically evaluate the support and universal applicability for oxygen limitation being involved in lethal temperatures in crustaceans and insects. The relatively few studies investigating the OCLTT hypothesis at low temperature do not support a universal role for oxygen in setting the lower thermal limits in arthropods. With respect to upper thermal limits, the evidence supporting OCLTT is stronger for species relying on underwater gas exchange, while the support for OCLTT in air-breathers is weak. Overall, strongest support was found for increased anaerobic metabolism close to thermal maxima. In contrast, there was only mixed support for the prediction that aerobic scope

  7. Non-uniform space charge limited current injection into a nano contact solid

    PubMed Central

    Zhu, Y. B.; Ang, L. K.

    2015-01-01

    We have developed a two-dimensional (2D) non-uniform model to study the space charge limited (SCL) current injection into a trap-filled solid of nano-contact, such as organic materials and dielectrics. Assuming a solid of length D with a contact of width W, the enhancement over the well-known 1D uniform model is calculated as a function of W/D for different material properties, such as the dielectric constant (ε) and the trap distribution. The non-uniform current density profile due to edge effect is predicted. The findings reported here are different from the prior uniform 2D models, which are significant for small W/D when the size of the contact reaching nanometer scale, i.e. W = 50 nm for D = 1 μm. This model will be useful for the characterization of carrier mobility and properties of traps, which are critical to many novel devices (with small nano-contact) operating in the space charge limited condition reporting in novel device and its applications. Empirical formulas are given for future comparison with experimental results. PMID:25779769

  8. Performance test of the cryogenic cooling system for the superconducting fault current limiter

    NASA Astrophysics Data System (ADS)

    Hong, Yong-Ju; In, Sehwan; Yeom, Han-Kil; Kim, Heesun; Kim, Hye-Rim

    2015-12-01

    A Superconducting Fault Current Limiter is an electric power device which limits the fault current immediately in a power grid. The SFCL must be cooled to below the critical temperature of high temperature superconductor modules. In general, they are submerged in sub-cooled liquid nitrogen for their stable thermal characteristics. To cool and maintain the target temperature and pressure of the sub-cooled liquid nitrogen, the cryogenic cooling system should be designed well with a cryocooler and coolant circulation devices. The pressure of the cryostat for the SFCL should be pressurized to suppress the generation of nitrogen bubbles in quench mode of the SFCL. In this study, we tested the performance of the cooling system for the prototype 154 kV SFCL, which consist of a Stirling cryocooler, a subcooling cryostat, a pressure builder and a main cryostat for the SFCL module, to verify the design of the cooling system and the electric performance of the SFCL. The normal operation condition of the main cryostat is 71 K and 500 kPa. This paper presents tests results of the overall cooling system.

  9. Non-uniform space charge limited current injection into a nano contact solid.

    PubMed

    Zhu, Y B; Ang, L K

    2015-01-01

    We have developed a two-dimensional (2D) non-uniform model to study the space charge limited (SCL) current injection into a trap-filled solid of nano-contact, such as organic materials and dielectrics. Assuming a solid of length D with a contact of width W, the enhancement over the well-known 1D uniform model is calculated as a function of W/D for different material properties, such as the dielectric constant (ε) and the trap distribution. The non-uniform current density profile due to edge effect is predicted. The findings reported here are different from the prior uniform 2D models, which are significant for small W/D when the size of the contact reaching nanometer scale, i.e. W = 50 nm for D = 1 μm. This model will be useful for the characterization of carrier mobility and properties of traps, which are critical to many novel devices (with small nano-contact) operating in the space charge limited condition reporting in novel device and its applications. Empirical formulas are given for future comparison with experimental results. PMID:25779769

  10. Study on Recovery Performance of High Tc Superconducting Tapes for Resistive Type Superconducting Fault Current Limiter Applications

    NASA Astrophysics Data System (ADS)

    kar, Soumen; Kulkarni, Sandeep; Dixit, Manglesh; Singh, Kuwar Pal; Gupta, Alok; Balasubramanyam, P. V.; Sarangi, S. K.; Rao, V. V.

    Recent advances in reliable production of long length high temperature superconducting (HTS) tapes have resulted in commercial application of superconducting fault current limiters (SFCLs) in electrical utility networks. SFCL gives excellent technical performance when compared to conventional fault current limiters. The fast self-recovery from normal state to superconducting state immediately after the fault removal is an essential criterion for resistive type SFCL operation. In this paper, results on AC over-current testing of 1st generation (1G) Bi2223 tapes and 2nd generation (2G) YBCO coated conductors operating at 77 K are reported. From these results, the recovery time is estimated for different available HTS tapes in the market. The current limiting tests have also been performed to study the effective current limitation. Further, the recovery characteristics after the current limitation are quantitatively discussed for repetitive faults for different time intervals in the range of 100 ms to few seconds.

  11. Test Results for a 25 Meter Prototype Fault Current Limiting Hts Cable for Project Hydra

    NASA Astrophysics Data System (ADS)

    Rey, C. M.; Duckworth, R. C.; Demko, J. A.; Ellis, A.; James, D. R.; Gouge, M. J.; Tuncer, E.

    2010-04-01

    The Oak Ridge National Laboratory (ORNL) has tested a 25-m long prototype High Temperature Superconducting (HTS) cable with inherent Fault-Current Limiting (FCL) capability at its HTS cable test facility. The HTS-FCL cable and terminations were designed and fabricated by Ultera, which is a joint venture between Southwire and nkt cables. System integration and HTS wire were provided by American Superconductor Corporation who was the overall team leader of the project. The ultimate goal of the 25-m HTS-FCL cable test program was to verify the design and ensure the operational integrity for the eventual installation of a ˜200-m fully functional HTS-FCL cable in the Consolidated Edison electric grid located in downtown New York City. The 25-m HTS-FCL cable consisted of a three-phase (3-Φ) HTS Triax™ design with a cold dielectric between the phases. The HTS-FCL cable had an operational voltage of 13.8 kV phase-to-phase (7967 V phase-to-ground) and an operating current of 4000 Arms per phase, which is the highest operating current to date of any HTS cable. The 25-m HTS-FCL cable was subjected to a series of cryogenic and electrical tests. Test results from the 25-m HTS-FCL cable are presented and discussed.

  12. Improvement of current limitation in the storage ring NIJI-IV

    SciTech Connect

    Yokoyama, M.; Kawai, M.; Hamada, S.

    1995-12-31

    The storage ring NIJI-IV dedicated to free-electron lasers was completed in December 1990. Lasing at 595-352 nm by using the NIJI-IV was accomplished by April 1994. The NIJI-IV has 16 rf-buckets. The electron bunch contributed to FEL gain of the NIJI-IV is only one of 16. In order to get the redundant bunch, make beam quality better, and make the FEL operation easier, a single bunch injection (SBI) system by using a short pulse beam from an electron gun was prepared. The quality of the beam accelerated and bunched by a buncher section has already been investigated. It was convinced that the accelerated short pulse beam satisfies the performance required on the SBI of the NIJI-IV. At present, the operation of the SBI system is being tested. Storage efficiency (the ratio of storage current to injection current) and limitation of storage current by using the SBI system will be reported in this conference. We expect lasing at below 352nm by the SBI.

  13. Limiter

    DOEpatents

    Cohen, Samuel A.; Hosea, Joel C.; Timberlake, John R.

    1986-01-01

    A limiter with a specially contoured front face accommodates the various power scrape-off distances .lambda..sub.p, which depend on the parallel velocity, V.sub..parallel., of the impacting particles. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution.

  14. Probing the upper limits of current flow in one-dimensional carbon conductors

    NASA Astrophysics Data System (ADS)

    Liao, Albert Daen

    We use breakdown thermometry to study carbon nanotube (CNT) devices and graphene nanoribbons (GNRs) on SiO2 substrates. Experiments and modeling find the CNT-substrate thermal coupling scales proportionally to CNT diameter. Diffuse mismatch modeling (DMM) reveals the upper limit of thermal coupling ˜0.7 WK-1m-1 for the largest diameter (3-4 nm) CNTs. Similarly, we extracted the GNR thermal conductivity (TC), ˜80 (130) Wm-1K-1 at 20 (600) °C across our samples, dominated by phonons, with estimated <10% electronic contribution. The TC of GNRs is an order of magnitude lower than that of micron-sized graphene on SiO2, suggesting strong roles of edge and defect scattering, and the importance of thermal dissipation in small GNR devices. We also compare the peak current density of metallic single-walled CNTs with GNRs. We find that as the "footprint" (width) between such a device and the underlying substrate decreases, heat dissipation becomes more efficient (for a given width), allowing for higher current densities. Because of their smaller dimensions and lack of edges, CNTs can carry larger current densities than GNRs, up to ˜16 mA/mum for an m-SWNT with a diameter of ˜0.7 nm versus ˜3 mA/mum for a GNR having a width of ˜15 nm. Such current densities are the highest possible in any diffusive conductor, to our knowledge. We also study semiconducting and metallic single-walled CNTs under vacuum. Sem-iconducting single-wall CNTs under high electric field stress (˜10 V/mum) display a re-markable current increase due to avalanche generation of free electrons and holes. Unlike in other materials, the avalanche process in such 1D quantum wires involves access to the third subband and is insensitive to temperature, but strongly dependent on diameter ˜exp(-1/d2). Comparison with a theoretical model yields a novel approach to obtain the inelastic optical phonon emission length, lambdaOP,ems ≈ 15 d nm. We find that current in metallic single-walled CNTs does not

  15. Intelligent Assistive Technology Applications to Dementia Care: Current Capabilities, Limitations, and Future Challenges

    PubMed Central

    Bharucha, Ashok J.; Anand, Vivek; Forlizzi, Jodi; Dew, Mary Amanda; Reynolds, Charles F.; Stevens, Scott; Wactlar, Howard

    2009-01-01

    The number of older Americans afflicted by Alzheimer disease and related dementias will triple to 13 million persons by 2050, thus greatly increasing healthcare needs. An approach to this emerging crisis is the development and deployment of intelligent assistive technologies that compensate for the specific physical and cognitive deficits of older adults with dementia, and thereby also reduce caregiver burden. The authors conducted an extensive search of the computer science, engineering, and medical databases to review intelligent cognitive devices, physiologic and environmental sensors, and advanced integrated sensor networks that may find future applications in dementia care. Review of the extant literature reveals an overwhelming focus on the physical disability of younger persons with typically nonprogressive anoxic and traumatic brain injuries, with few clinical studies specifically involving persons with dementia. A discussion of the specific capabilities, strengths, and limitations of each technology is followed by an overview of research methodological challenges that must be addressed to achieve measurable progress to meet the healthcare needs of an aging America. PMID:18849532

  16. Inaugural address

    NASA Astrophysics Data System (ADS)

    Joshi, P. S.

    2014-03-01

    was how IAGRG was born, and currently the association has about 350 members, both from within India and abroad. The full inaugural address is available in the PDF

  17. Theoretical speed and current density limits for different types of electrical brushes

    NASA Astrophysics Data System (ADS)

    Kuhlmann-Wilsdorf, D.

    1984-03-01

    Theoretical performance limits based on the criterion of flash temperature are investigated for monolithic Ag-C brushes, Cu-on-Cu brushes with elastic contact spots, and 'QM' brushes (Quantum Mechanical brushes with ultrathin metal fibers), in which ordinary current conduction is significantly supplemented by electron tunneling peripherally about the contact spots. Equations are developed for the contact spot radii and heat input rates for frictional and electrical heating at the contact spots. Typical data for the flash temperatures are calculated for the high-speed approximation for plastic and elastic contact spots. The low-speed approximation is used for QM brushes. It is concluded that metal fiber and/or QM brushes may represent the best solution to the brush problem for electromagnetic launching.

  18. Current Trends about Inner Limiting Membrane Peeling in Surgery for Epiretinal Membranes

    PubMed Central

    Semeraro, Francesco; Morescalchi, Francesco; Duse, Sarah; Gambicorti, Elena; Russo, Andrea; Costagliola, Ciro

    2015-01-01

    The inner limiting membrane (ILM) is the basement membrane of the Müller cells and can act as a scaffold for cellular proliferation in the pathophysiology of disorders affecting the vitreomacular interface. The atraumatic removal of the macular ILM has been proposed for treating various forms of tractional maculopathy in particular for macular pucker. In the last decade, the removal of ILM has become a routine practice in the surgery of the epiretinal membranes (ERMs), with good anatomical results. However many recent studies showed that ILM peeling is a procedure that can cause immediate traumatic effects and progressive modification on the underlying inner retinal layers. Moreover, it is unclear whether ILM peeling is helpful to improve vision after surgery for ERM. In this review, we describe the current understanding about ILM peeling and highlight the beneficial and adverse effects associated with this surgical procedure. PMID:26425352

  19. Successful Nd:Yag Laser Photocoagulation Of Arrhythmogenic Myocardium: Potential Limitations Of Current Optical Delivery Systems.

    NASA Astrophysics Data System (ADS)

    Svenson, Robert H.; Marroum, Marie-Claire; Frank, Frank; Selle, Jay G.; Gallagher, John J.; Bou-Saba, George; Seifert, Kathleen T.; Linder, Kathy; Tatsis, George P.

    1987-04-01

    Canine myocardial lesions of predictable dimensions can be achieved with Nd:YAG laser photocoagulation. These lesions are well demarcated from surrounding normal tissue and heal with homogeneous scar formation. Intraoperative Nd:YAG laser photocoagulation successfully ablated 52 of 55 ventricular tachycardias in 17 patients. Histologic examination of tissues from these arrhythmogenic areas showed differences from lesions produced on canine epicardium. Lesions from the human cases were less predictable and not well circumscribed. These differences are felt to be due to optical inhomogeneities present in diseased, scarred human myocardium, geometric irregularities of the endocardial surface, anatomical constraints on tissue-fiber distance, and the angle of incidence of the beam with the tissue. Modifications of current delivery systems may overcome some of these limitations. Ablation of ventricular tachycardia arising deeper than 4.0 to 6.0 mm. from the irradiated surface may require interstitial probes coupled to the fiberoptic.

  20. Strategies for medical data extraction and presentation part 1: current limitations and deficiencies.

    PubMed

    Reiner, Bruce

    2015-04-01

    Data overload is a burgeoning challenge for the medical imaging community; with resulting technical, clinical, and economic ramifications. A primary concern for radiologists is the timely, efficient, and accurate extraction of imaging and clinical data, which collectively are essential in determining accurate diagnosis. In current practice, imaging data retrieval is limited by the fact that imaging and report data are de-coupled from one another, along with the non-standardized and often ambiguous free text data contained within narrative radiology reports. Clinical data retrieval is equally challenging and flawed by the lack of information system integration, paucity of clinical order entry data, and diminished role of the technologist in providing clinical data. These combined factors have the potential to adversely affect radiologist performance and clinical outcomes by diminishing workflow, report accuracy, and diagnostic confidence. New and innovative strategies are required to improve and automate data extraction and presentation, in a context- and user-specific fashion. PMID:25666903

  1. Modeling practical performance limits of photoelectrochemical water splitting based on the current state of materials research.

    PubMed

    Seitz, Linsey C; Chen, Zhebo; Forman, Arnold J; Pinaud, Blaise A; Benck, Jesse D; Jaramillo, Thomas F

    2014-05-01

    Photoelectrochemical (PEC) water splitting is a means to store solar energy in the form of hydrogen. Knowledge of practical limits for this process can help researchers assess their technology and guide future directions. We develop a model to quantify loss mechanisms in PEC water splitting based on the current state of materials research and calculate maximum solar-to-hydrogen (STH) conversion efficiencies along with associated optimal absorber band gaps. Various absorber configurations are modeled considering the major loss mechanisms in PEC devices. Quantitative sensitivity analyses for each loss mechanism and each absorber configuration show a profound impact of both on the resulting STH efficiencies, which can reach upwards of 25 % for the highest performance materials in a dual stacked configuration. Higher efficiencies could be reached as improved materials are developed. The results of the modeling also identify and quantify approaches that can improve system performance when working with imperfect materials.

  2. Biochemical markers of ongoing joint damage in rheumatoid arthritis - current and future applications, limitations and opportunities

    PubMed Central

    2011-01-01

    Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease associated with potentially debilitating joint inflammation, as well as altered skeletal bone metabolism and co-morbid conditions. Early diagnosis and aggressive treatment to control disease activity offers the highest likelihood of preserving function and preventing disability. Joint inflammation is characterized by synovitis, osteitis, and/or peri-articular osteopenia, often accompanied by development of subchondral bone erosions, as well as progressive joint space narrowing. Biochemical markers of joint cartilage and bone degradation may enable timely detection and assessment of ongoing joint damage, and their use in facilitating treatment strategies is under investigation. Early detection of joint damage may be assisted by the characterization of biochemical markers that identify patients whose joint damage is progressing rapidly and who are thus most in need of aggressive treatment, and that, alone or in combination, identify those individuals who are likely to respond best to a potential treatment, both in terms of limiting joint damage and relieving symptoms. The aims of this review are to describe currently available biochemical markers of joint metabolism in relation to the pathobiology of joint damage and systemic bone loss in RA; to assess the limitations of, and need for additional, novel biochemical markers in RA and other rheumatic diseases, and the strategies used for assay development; and to examine the feasibility of advancement of personalized health care using biochemical markers to select therapeutic agents to which a patient is most likely to respond. PMID:21539724

  3. Animal models of human colorectal cancer: Current status, uses and limitations

    PubMed Central

    Mittal, Vijay K; Bhullar, Jasneet Singh; Jayant, Kumar

    2015-01-01

    AIM: To make orthotopic colon cancer murine models a more clearly understood subject. The orthotopic tumor models have been found to be more relevant in replicating the human disease process as compared to heterotopic models, many techniques for making orthotopic colorectal murine models have been reported. METHODS: We evaluated the current literature for various reported orthotopic colon cancer models to understand their techniques, advantages and limitations. An extensive literature review was performed by searching the National Library of Medicine Database (PubMed) using MeSH terms animal model; colon cancer; orthotopic model; murine model. Twenty studies related to colon cancer orthotopic xenograft model were evaluated in detail and discussed here. RESULTS: The detailed analysis of all relevant reports on orthotopic model showed tumor take rate between 42%-100%. While models using the enema technique and minimally invasive technique have reported development of tumor from mucosa with tumor take rate between 87%-100% with metastasis in 76%-90%. CONCLUSION: Over the years, the increased understanding of the murine models of human colon cancer has resulted in the development of various models. Each reported model has some limitations. These latest models have opened up new doors for continuing cancer research for not only understanding the colon cancer pathogenesis but also aid in the development of newer chemotherapeutic drugs as they mimic the human disease closely. PMID:26557009

  4. Current methodological and technical limitations of time and volumetric capnography in newborns.

    PubMed

    Schmalisch, Gerd

    2016-01-01

    Although capnography is a standard tool in mechanically ventilated adult and pediatric patients, it has physiological and technical limitations in neonates. Gas exchange differs between small and adult lungs due to the greater impact of small airways on gas exchange, the higher impact of the apparatus dead space on measurements due to lower tidal volume and the occurrence of air leaks in intubated patients. The high respiratory rate and low tidal volume in newborns, especially those with stiff lungs, require main-stream sensors with fast response times and minimal dead-space or low suction flow when using side-stream measurements. If these technical requirements are not fulfilled, the measured end-tidal CO2 (P et CO 2 ), which should reflect the alveolar CO2 and the calculated airway dead spaces, can be misleading. The aim of this survey is to highlight the current limitations of capnography in very young patients to avoid pitfalls associated with the interpretation of capnographic parameters, and to describe further developments. PMID:27576441

  5. Ontological analysis of gene expression data: current tools, limitations, and open problems

    PubMed Central

    Khatri, Purvesh

    2008-01-01

    Summary Independent of the platform and the analysis methods used, the result of a microarray experiment is, in most cases, a list of differentially expressed genes. An automatic ontological analysis approach has been recently proposed to help with the biological interpretation of such results. Currently, this approach is the de facto standard for the secondary analysis of high throughput experiments and a large number of tools have been developed for this purpose. We present a detailed comparison of 14 such tools using the following criteria: scope of the analysis, visualization capabilities, statistical model(s) used, correction for multiple comparisons, reference microar-rays available, installation issues and sources of annotation data. This detailed analysis of the capabilities of these tools will help researchers choose the most appropriate tool for a given type of analysis. More importantly, in spite of the fact that this type of analysis has been generally adopted, this approach has several important intrinsic drawbacks. These drawbacks are associated with all tools discussed and represent conceptual limitations of the current state-of-the-art in ontological analysis. We propose these as challenges for the next generation of secondary data analysis tools. Contact sod@cs.wayne.edu PMID:15994189

  6. Scoring of coronary artery calcium scans: history, assumptions, current limitations, and future directions.

    PubMed

    Alluri, Krishna; Joshi, Parag H; Henry, Travis S; Blumenthal, Roger S; Nasir, Khurram; Blaha, Michael J

    2015-03-01

    Coronary artery calcium (CAC) scanning is a reliable, noninvasive technique for estimating overall coronary plaque burden and for identifying risk for future cardiac events. Arthur Agatston and Warren Janowitz published the first technique for scoring CAC scans in 1990. Given the lack of available data correlating CAC with burden of coronary atherosclerosis at that time, their scoring algorithm was remarkable, but somewhat arbitrary. Since then, a few other scoring techniques have been proposed for the measurement of CAC including the Volume score and Mass score. Yet despite new data, little in this field has changed in the last 15 years. The main focus of our paper is to review the implications of the current approach to scoring CAC scans in terms of correlation with the central disease - coronary atherosclerosis. We first discuss the methodology of each available scoring system, describing how each of these scores make important indirect assumptions in the way they account (or do not account) for calcium density, location of calcium, spatial distribution of calcium, and microcalcification/emerging calcium that might limit their predictive power. These assumptions require further study in well-designed, large event-driven studies. In general, all of these scores are adequate and are highly correlated with each other. Despite its age, the Agatston score remains the most extensively studied and widely accepted technique in both the clinical and research settings. After discussing CAC scoring in the era of contrast enhanced coronary CT angiography, we discuss suggested potential modifications to current CAC scanning protocols with respect to tube voltage, tube current, and slice thickness which may further improve the value of CAC scoring. We close with a focused discussion of the most important future directions in the field of CAC scoring. PMID:25585030

  7. Assessment on the influence of resistive superconducting fault current limiter in VSC-HVDC system

    NASA Astrophysics Data System (ADS)

    Lee, Jong-Geon; Khan, Umer Amir; Hwang, Jae-Sang; Seong, Jae-Kyu; Shin, Woo-Ju; Park, Byung-Bae; Lee, Bang-Wook

    2014-09-01

    Due to fewer risk of commutation failures, harmonic occurrences and reactive power consumptions, Voltage Source Converter (VSC) based HVDC system is known as the optimum solution of HVDC power system for the future power grid. However, the absence of suitable fault protection devices for HVDC system hinders the efficient VSC-HVDC power grid design. In order to enhance the reliability of the VSC-HVDC power grid against the fault current problems, the application of resistive Superconducting Fault Current Limiters (SFCLs) could be considered. Also, SFCLs could be applied to the VSC-HVDC system with integrated AC Power Systems in order to enhance the transient response and the robustness of the system. In this paper, in order to evaluate the role of SFCLs in VSC-HVDC systems and to determine the suitable position of SFCLs in VSC-HVDC power systems integrated with AC power System, a simulation model based on Korea Jeju-Haenam HVDC power system was designed in Matlab Simulink/SimPowerSystems. This designed model was composed of VSC-HVDC system connected with an AC microgrid. Utilizing the designed VSC-HVDC systems, the feasible locations of resistive SFCLs were evaluated when DC line-to-line, DC line-to-ground and three phase AC faults were occurred. Consequently, it was found that the simulation model was effective to evaluate the positive effects of resistive SFCLs for the effective suppression of fault currents in VSC-HVDC systems as well as in integrated AC Systems. Finally, the optimum locations of SFCLs in VSC-HVDC transmission systems were suggested based on the simulation results.

  8. Mechanistic insights for the development of Li-O2 battery materials: addressing Li2O2 conductivity limitations and electrolyte and cathode instabilities.

    PubMed

    McCloskey, Bryan D; Burke, Colin M; Nichols, Jessica E; Renfrew, Sara E

    2015-08-18

    The Li-air battery has received significant attention over the past decade given its high theoretical specific energy compared to competing energy storage technologies. Yet, numerous scientific challenges remain unsolved in the pursuit of attaining a battery with modest Coulombic efficiency and high capacity. In this Feature Article, we provide our current perspective on challenges facing the development of nonaqueous Li-O2 battery cathodes. We initially present a review on our understanding of electrochemical processes occurring at the nonaqueous Li-O2 cathode. Electrolyte and cathode instabilities and Li2O2 conductivity limitations are then discussed, and suggestions for future materials research development to alleviate these issues are provided. PMID:26179598

  9. Natural Products in Caries Research: Current (Limited) Knowledge, Challenges and Future Perspective

    PubMed Central

    Jeon, J.-G; Rosalen, P.L.; Falsetta, M.L.; Koo, H.

    2011-01-01

    Dental caries is the most prevalent and costly oral infectious disease worldwide. Virulent biofilms firmly attached to tooth surfaces are prime biological factors associated with this disease. The formation of an exopolysaccharide-rich biofilm matrix, acidification of the milieu and persistent low pH at the tooth-biofilm interface are major controlling virulence factors that modulate dental caries pathogenesis. Each one offers a selective therapeutic target for prevention. Although fluoride, delivered in various modalities, remains the mainstay for the prevention of caries, additional approaches are required to enhance its effectiveness. Available antiplaque approaches are based on the use of broad-spectrum microbicidal agents, e.g. chlorhexidine. Natural products offer a rich source of structurally diverse substances with a wide range of biological activities, which could be useful for the development of alternative or adjunctive anticaries therapies. However, it is a challenging approach owing to complex chemistry and isolation procedures to derive active compounds from natural products. Furthermore, most of the studies have been focused on the general inhibitory effects on glucan synthesis as well as on bacterial metabolism and growth, often employing methods that do not address the pathophysiological aspects of the disease (e.g. bacteria in biofilms) and the length of exposure/retention in the mouth. Thus, the true value of natural products in caries prevention and/or their exact mechanisms of action remain largely unknown. Nevertheless, natural substances potentially active against virulent properties of cariogenic organisms have been identified. This review focuses on gaps in the current knowledge and presents a model for investigating the use of natural products in anticaries chemotherapy. PMID:21576957

  10. Dual Purpose Simulation: New Data Link Test and Performance Limit Testing of Currently Deployed Data Link

    NASA Technical Reports Server (NTRS)

    Robinson, Daryl C.

    2002-01-01

    While the results of this paper are similar to those of [I], in this paper technical difficulties present in [I] are eliminated, producing better results, enabling one to more readily see the benefits of Prioritized CSMA (PCSMA). A new analysis section also helps to generalize this research so that it is not limited to exploration of the new concept of PCSMA. Commercially available network simulation software, OPNET version 7.0, simulations are presented involving an important application of the Aeronautical Telecommunications Network (ATN), Controller Pilot Data Link Communications (CPDLC) over the Very High Frequency Data Link Mode 2 (VDL-2). Communication is modeled for essentially all incoming and outgoing nonstop air-traffic for just three United States cities: Cleveland, Cincinnati, and Detroit. The simulation involves 111 Air Traffic Control (ATC) ground stations, 32 airports distributed throughout the U.S., which are either sources or destinations for the air traffic landing or departing from the three cities, and also 1,235 equally equipped aircraft-taking off, flying realistic free-flight trajectories, and landing in a 24-hr period. Collision-less PCSMA is successfully tested and compared with the traditional CSMA typically associated with VDL-2. The performance measures include latency, throughput, and packet loss. As expected, PCSMA is much quicker and more efficient than traditional CSMA. These simulation results show the potency of PCSMA for implementing low latency, high throughput and efficient connectivity. Moreover, since PCSMA outperforms traditional CSMA, by simulating with it, we can determine the limits of performance beyond which traditional CSMA may not pass. So we have the tools to determine the traffic-loading conditions where traditional CSMA will fail, and we are testing a new and better data link that could replace it with relative ease. Work is currently being done to drastically expand the number of flights to make the simulation more

  11. Welcome Address

    NASA Astrophysics Data System (ADS)

    Kiku, H.

    2014-12-01

    Ladies and Gentlemen, It is an honor for me to present my welcome address in the 3rd International Workshop on "State of the Art in Nuclear Cluster Physics"(SOTANCP3), as the president of Kanto Gakuin University. Particularly to those from abroad more than 17 countries, I am very grateful for your participation after long long trips from your home to Yokohama. On the behalf of the Kanto Gakuin University, we certainly welcome your visit to our university and stay in Yokohama. First I would like to introduce Kanto Gakuin University briefly. Kanto Gakuin University, which is called KGU, traces its roots back to the Yokohama Baptist Seminary founded in 1884 in Yamate, Yokohama. The seminary's founder was Albert Arnold Bennett, alumnus of Brown University, who came to Japan from the United States to establish a theological seminary for cultivating and training Japanese missionaries. Now KGU is a major member of the Kanto Gakuin School Corporation, which is composed of two kindergartens, two primary schools, two junior high schools, two senior high schools as well as KGU. In this university, we have eight faculties with graduate school including Humanities, Economics, Law, Sciences and Engineering, Architecture and Environmental Design, Human and Environmental Studies, Nursing, and Law School. Over eleven thousands students are currently learning in our university. By the way, my major is the geotechnical engineering, and I belong to the faculty of Sciences and Engineering in my university. Prof. T. Yamada, here, is my colleague in the same faculty. I know that the nuclear physics is one of the most active academic fields in the world. In fact, about half of the participants, namely, more than 50 scientists, come from abroad in this conference. Moreover, I know that the nuclear physics is related to not only the other fundamental physics such as the elementary particle physics and astrophysics but also chemistry, medical sciences, medical cares, and radiation metrology

  12. Clinical Uses of Botulinum Neurotoxins: Current Indications, Limitations and Future Developments

    PubMed Central

    Chen, Sheng

    2012-01-01

    Botulinum neurotoxins (BoNTs) cause flaccid paralysis by interfering with vesicle fusion and neurotransmitter release in the neuronal cells. BoNTs are the most widely used therapeutic proteins. BoNT/A was approved by the U.S. FDA to treat strabismus, blepharospam, and hemificial spasm as early as 1989 and then for treatment of cervical dystonia, glabellar facial lines, axillary hyperhidrosis, chronic migraine and for cosmetic use. Due to its high efficacy, longevity of action and satisfactory safety profile, it has been used empirically in a variety of ophthalmological, gastrointestinal, urological, orthopedic, dermatological, secretory, and painful disorders. Currently available BoNT therapies are limited to neuronal indications with the requirement of periodic injections resulting in immune-resistance for some indications. Recent understanding of the structure-function relationship of BoNTs prompted the engineering of novel BoNTs to extend therapeutic interventions in non-neuronal systems and to overcome the immune-resistance issue. Much research still needs to be done to improve and extend the medical uses of BoNTs. PMID:23162705

  13. Modeling Interfacial Glass-Water Reactions: Recent Advances and Current Limitations

    DOE PAGES

    Pierce, Eric M.; Frugier, Pierre; Criscenti, Louise J.; Kwon, Kideok D.; Kerisit, Sebastien N.

    2014-07-12

    Describing the reactions that occur at the glass-water interface and control the development of the altered layer constitutes one of the main scientific challenges impeding existing models from providing accurate radionuclide release estimates. Radionuclide release estimates are a critical component of the safety basis for geologic repositories. The altered layer (i.e., amorphous hydrated surface layer and crystalline reaction products) represents a complex region, both physically and chemically, sandwiched between two distinct boundaries pristine glass surface at the inner most interface and aqueous solution at the outer most interface. Computational models, spanning different length and time-scales, are currently being developed tomore » improve our understanding of this complex and dynamic process with the goal of accurately describing the pore-scale changes that occur as the system evolves. These modeling approaches include geochemical simulations [i.e., classical reaction path simulations and glass reactivity in allowance for alteration layer (GRAAL) simulations], Monte Carlo simulations, and Molecular Dynamics methods. Finally, in this manuscript, we discuss the advances and limitations of each modeling approach placed in the context of the glass-water reaction and how collectively these approaches provide insights into the mechanisms that control the formation and evolution of altered layers.« less

  14. Modeling Interfacial Glass-Water Reactions: Recent Advances and Current Limitations

    SciTech Connect

    Pierce, Eric M.; Frugier, Pierre; Criscenti, Louise J.; Kwon, K. D.; Kerisit, Sebastien N.

    2014-07-12

    The altered layer (i.e., amorphous hydrated surface layer and crystalline reaction products)represents a complex region, both physically and chemically, sandwiched between two distinct boundaries - pristine glass surface at the inner most interface and aqueous solution at the outer most. The physico-chemical processes that control the development of this region have a significant impact on the long-term glass-water reaction. Computational models, spanning different length and time-scales, are currently being developed to improve our understanding of this complex and dynamic process with the goal of accurately describing the pore-scale changes that occur as the system evolves. These modeling approaches include Geochemical Reaction Path simulations, Glass Reactivity in Allowance for Alteration Layer simulations, Monte Carlo simulations, and Molecular Dynamics methods. Discussed in this manuscript are the advances and limitations of each modeling approach placed in the context of the glass water reaction and how collectively these approaches provide insights into the mechanisms that control the formation and evolution of altered layers; thus providing the fundamental data needed to develop pore-scale equations that enable more accurate predictions of nuclear waste glass corrosion in a geologic repository.

  15. Evaluation of Bag-Valve-Mask Ventilation in Manikin Studies: What Are the Current Limitations?

    PubMed Central

    Pugin, A.; Pili-Floury, S.; Pazart, L.; Capellier, G.

    2016-01-01

    Introduction. Manikin-based studies for evaluation of ventilation performance show high heterogeneity in the analysis and experimental methods used as we pointed out in previous studies. In this work, we aim to evaluate these potential limitations and propose a new analysis methodology to reliably assess ventilation performance. Methods. One hundred forty healthcare providers were selected to ventilate a manikin with two adult self-inflating bags in random order. Ventilation parameters were analysed using different published analysis methods compared to ours. Results. Using different methods impacts the evaluation of ventilation efficiency which ranges from 0% to 45.71%. Our new method proved relevant and showed that all professionals tend to cause hyperventilation and revealed a significant relationship between professional category, grip strength of the hand keeping the mask, and ventilation performance (p = 0.0049 and p = 0.0297, resp.). Conclusion. Using adequate analysis methods is crucial to avoid many biases. Extrapolations to humans still have to be taken with caution as many factors impact the evaluation of ventilation performance. Healthcare professionals tend to cause hyperventilation with current devices. We believe this problem could be prevented by implementing monitoring tools in order to give direct feedback to healthcare professionals regarding ventilation efficiency and ventilatory parameter values. PMID:27294119

  16. Combining Pharmacological and Psychological Treatments for Binge Eating Disorder: Current Status, Limitations, and Future Directions.

    PubMed

    Grilo, Carlos M; Reas, Deborah L; Mitchell, James E

    2016-06-01

    Binge eating disorder (BED) is characterized by recurrent binge eating and marked distress about binge eating without the extreme compensatory behaviors for weight control that characterize other eating disorders. BED is prevalent, associated strongly with obesity, and is associated with heightened levels of psychological, psychiatric, and medical concerns. This article provides an overview of randomized controlled treatments for combined psychological and pharmacological treatment of BED to inform current clinical practice and future treatment research. In contrast to the prevalence and significance of BED, to date, limited research has been performed on combining psychological and pharmacological treatments for BED to enhance outcomes. Our review here found that combining certain medications with cognitive behavioral therapy (CBT) or behavioral weight loss (BWL) interventions produces superior outcomes to pharmacotherapy only but does not substantially improve outcomes achieved with CBT/BWL only. One medication (orlistat) has improved weight losses with CBT/BWL albeit minimally, and only one medication (topiramate) has enhanced reductions achieved with CBT in both binge eating and weight. Implications for future research are discussed.

  17. Combining Pharmacological and Psychological Treatments for Binge Eating Disorder: Current Status, Limitations, and Future Directions.

    PubMed

    Grilo, Carlos M; Reas, Deborah L; Mitchell, James E

    2016-06-01

    Binge eating disorder (BED) is characterized by recurrent binge eating and marked distress about binge eating without the extreme compensatory behaviors for weight control that characterize other eating disorders. BED is prevalent, associated strongly with obesity, and is associated with heightened levels of psychological, psychiatric, and medical concerns. This article provides an overview of randomized controlled treatments for combined psychological and pharmacological treatment of BED to inform current clinical practice and future treatment research. In contrast to the prevalence and significance of BED, to date, limited research has been performed on combining psychological and pharmacological treatments for BED to enhance outcomes. Our review here found that combining certain medications with cognitive behavioral therapy (CBT) or behavioral weight loss (BWL) interventions produces superior outcomes to pharmacotherapy only but does not substantially improve outcomes achieved with CBT/BWL only. One medication (orlistat) has improved weight losses with CBT/BWL albeit minimally, and only one medication (topiramate) has enhanced reductions achieved with CBT in both binge eating and weight. Implications for future research are discussed. PMID:27086316

  18. Modeling Interfacial Glass-Water Reactions: Recent Advances and Current Limitations

    SciTech Connect

    Pierce, Eric M.; Frugier, Pierre; Criscenti, Louise J.; Kwon, Kideok D.; Kerisit, Sebastien N.

    2014-07-12

    Describing the reactions that occur at the glass-water interface and control the development of the altered layer constitutes one of the main scientific challenges impeding existing models from providing accurate radionuclide release estimates. Radionuclide release estimates are a critical component of the safety basis for geologic repositories. The altered layer (i.e., amorphous hydrated surface layer and crystalline reaction products) represents a complex region, both physically and chemically, sandwiched between two distinct boundaries pristine glass surface at the inner most interface and aqueous solution at the outer most interface. Computational models, spanning different length and time-scales, are currently being developed to improve our understanding of this complex and dynamic process with the goal of accurately describing the pore-scale changes that occur as the system evolves. These modeling approaches include geochemical simulations [i.e., classical reaction path simulations and glass reactivity in allowance for alteration layer (GRAAL) simulations], Monte Carlo simulations, and Molecular Dynamics methods. Finally, in this manuscript, we discuss the advances and limitations of each modeling approach placed in the context of the glass-water reaction and how collectively these approaches provide insights into the mechanisms that control the formation and evolution of altered layers.

  19. Advances in enantioselective analysis of chiral brominated flame retardants. Current status, limitations and future perspectives.

    PubMed

    Badea, Silviu-Laurentiu; Niculescu, Violeta Carolina; Ionete, Roxana-Elena; Eljarrat, Ethel

    2016-10-01

    Enantioselective analysis is a powerful tool for the discrimination of biotic and abiotic transformation processes of chiral environmental contaminants because their environmental biodegradation is mostly stereospecific. However, it is challenging when applied to new contaminants since enantioselective analysis methods are currently available only for a limited number of compounds. The enantioselective analysis of chiral novel brominated flame retardants (NBFRs) either using gas chromatography (GC) or liquid chromatography (LC) with various chiral stationary phases (CSP) coupled with various mass spectrometric techniques was extensively discussed. The elution order of hexabromocyclododecane (HBCD) enantiomers in chiral LC was reviewed using the experimental LC data combined also with predictions from a multi-mode Hamiltonian dynamics simulation model based on interaction energies of HBCD enantiomers with β-permethylated cyclodextrin. The further development of analytical methodologies for new chiral BFRs using advanced hyphenated analytical techniques, but also the next generation mass spectrometer analyzers (i.e. GC-Qrbitrap MS-MS, LC-Qrbitrap MS-MS), will contribute to a better characterization of the transformation pathways of chiral BFRs.

  20. Possibilities and limitations of current technologies for quantification of biological extracellular vesicles and synthetic mimics

    PubMed Central

    Maas, Sybren L.N.; de Vrij, Jeroen; van der Vlist, Els J.; Geragousian, Biaina; van Bloois, Louis; Mastrobattista, Enrico; Schiffelers, Raymond M.; Wauben, Marca H.M.; Broekman, Marike L.D.; Nolte-'t Hoen, Esther N.M.

    2015-01-01

    Nano-sized extracelullar vesicles (EVs) released by various cell types play important roles in a plethora of (patho)physiological processes and are increasingly recognized as biomarkers for disease. In addition, engineered EV and EV-inspired liposomes hold great potential as drug delivery systems. Major technologies developed for high-throughput analysis of individual EV include nanoparticle tracking analysis (NTA), tunable resistive pulse sensing (tRPS) and high-resolution flow cytometry (hFC). Currently, there is a need for comparative studies on the available technologies to improve standardization of vesicle analysis in diagnostic or therapeutic settings. We investigated the possibilities, limitations and comparability of NTA, tRPS and hFC for analysis of tumor cell-derived EVs and synthetic mimics (i.e. differently sized liposomes). NTA and tRPS instrument settings were identified that significantly affected the quantification of these particles. Furthermore, we detailed the differences in absolute quantification of EVs and liposomes using the three technologies. This study increases our understanding of possibilities and pitfalls of NTA, tRPS and hFC, which will benefit standardized and large-scale clinical application of (engineered) EVs and EV-mimics in the future. PMID:25555362

  1. Advances in enantioselective analysis of chiral brominated flame retardants. Current status, limitations and future perspectives.

    PubMed

    Badea, Silviu-Laurentiu; Niculescu, Violeta Carolina; Ionete, Roxana-Elena; Eljarrat, Ethel

    2016-10-01

    Enantioselective analysis is a powerful tool for the discrimination of biotic and abiotic transformation processes of chiral environmental contaminants because their environmental biodegradation is mostly stereospecific. However, it is challenging when applied to new contaminants since enantioselective analysis methods are currently available only for a limited number of compounds. The enantioselective analysis of chiral novel brominated flame retardants (NBFRs) either using gas chromatography (GC) or liquid chromatography (LC) with various chiral stationary phases (CSP) coupled with various mass spectrometric techniques was extensively discussed. The elution order of hexabromocyclododecane (HBCD) enantiomers in chiral LC was reviewed using the experimental LC data combined also with predictions from a multi-mode Hamiltonian dynamics simulation model based on interaction energies of HBCD enantiomers with β-permethylated cyclodextrin. The further development of analytical methodologies for new chiral BFRs using advanced hyphenated analytical techniques, but also the next generation mass spectrometer analyzers (i.e. GC-Qrbitrap MS-MS, LC-Qrbitrap MS-MS), will contribute to a better characterization of the transformation pathways of chiral BFRs. PMID:27265736

  2. Clinical uses of botulinum neurotoxins: current indications, limitations and future developments.

    PubMed

    Chen, Sheng

    2012-10-01

    Botulinum neurotoxins (BoNTs) cause flaccid paralysis by interfering with vesicle fusion and neurotransmitter release in the neuronal cells. BoNTs are the most widely used therapeutic proteins. BoNT/A was approved by the U.S. FDA to treat strabismus, blepharospam, and hemificial spasm as early as 1989 and then for treatment of cervical dystonia, glabellar facial lines, axillary hyperhidrosis, chronic migraine and for cosmetic use. Due to its high efficacy, longevity of action and satisfactory safety profile, it has been used empirically in a variety of ophthalmological, gastrointestinal, urological, orthopedic, dermatological, secretory, and painful disorders. Currently available BoNT therapies are limited to neuronal indications with the requirement of periodic injections resulting in immune-resistance for some indications. Recent understanding of the structure-function relationship of BoNTs prompted the engineering of novel BoNTs to extend therapeutic interventions in non-neuronal systems and to overcome the immune-resistance issue. Much research still needs to be done to improve and extend the medical uses of BoNTs.

  3. Investigations of current limiting properties of the MgB2 wires subjected to pulse overcurrents in the benchtop tester

    NASA Astrophysics Data System (ADS)

    Ye, Lin; Majoros, M.; Campbell, A. M.; Coombs, T.; Harrison, S.; Sargent, P.; Haslett, M.; Husband, M.

    2007-04-01

    A laboratory scale desktop test system including a cryogenic system, an AC pulse generation system and a real time data acquisition program in LabView/DAQmx, has been developed to evaluate the quench properties of MgB2 wires as an element in a superconducting fault current limiter under pulse overcurrents at 25 K in self-field conditions. The MgB2 samples started from a superconducting state and demonstrated good current limiting properties characterized by a fast transition to the normal state during the first half of the cycle and a continuously limiting effect in the subsequent cycles without burnouts. The experimental and numerical simulation results on the quench behaviour indicate the feasibility of using MgB2 for future superconducting fault current limiter (SFCL) applications. This work is supported by Rolls-Royce Plc and the UK Department of Trade & Industry (DTI).

  4. Addressing healthcare.

    PubMed

    Daly, Rich

    2013-02-11

    Though President Barack Obama has rarely made healthcare references in his State of the Union addresses, health policy experts are hoping he changes that strategy this year. "The question is: Will he say anything? You would hope that he would, given that that was the major issue he started his presidency with," says Dr. James Weinstein, left, of the Dartmouth-Hitchcock health system. PMID:23487896

  5. Aerospace technology development of three types of solid state remote power controllers for 120VDC with current ratings of five, and thirty amperes, one type having current limiting

    NASA Technical Reports Server (NTRS)

    Baker, D. E.

    1975-01-01

    The first generation of remote power controllers (RPC) developed included: a 5-ampere design (Type 1), capable of limiting maximum overload current to 15 amperes for .1 sec; and 5-ampere noncurrent (Type 2) and 30-ampere noncurrent (Type 3) limiting designs, both with selectable instant trip levels for high-current overload. Each design provides overcurrent protection through an inverse I squared T trip-out function with an automatic reset option and demonstrates step-applied fault capability with a 4000-ampere surge, fast-risetime (low-inductance) power source. They also meet MIL - STD - 461A specification for electromagnetic interference. The second generation RPCs traded off specification compliance for reduction in cost and complexity for the Type 1 and 2 designs and give comparable or improved performance in most areas. The noncurrent limiting RPC proved to be a more economical and feasible method of overload protection for certain load types.

  6. Limiting dark current mechanisms in antimony-based superlattice infrared detectors for the long-wavelength infrared regime

    NASA Astrophysics Data System (ADS)

    Rehm, Robert; Lemke, Florian; Schmitz, Johannes; Wauro, Matthias; Walther, Martin

    2015-06-01

    A detailed understanding of limiting dark current mechanisms in InAs/GaSb type-II superlattice (T2SL) infrared detectors is key to improve the electrooptical performance of these devices. We present a six-component dark current analysis which, for the first time, takes account of sidewall-related dark current contributions in mesa-etched T2SL photodiodes. In a wide temperature range from 30K to 130K, the paper compares limiting mechanisms in two homojunction T2SL photodiode wafers for the long-wavelength infrared regime. While the two epi wafers were fabricated with nominally the same frontside process they were grown on different molecular beam epitaxy systems. In the available literature a limitation by Shockley-Read-Hall processes in the space charge region giving rise to generation-recombination (GR) dark current is the prevailing verdict on the bulk dark current mechanism in T2SL homojunction photodiodes around 77K. In contrast, we find that investigated photodiode wafers are instead limited by the diffusion mechanism and the ohmic shunt component, respectively. Furthermore, our in-depth analysis of the various dark current components has led to an interesting observation on the temperature dependence of the shunt resistance in T2SL homojunction photodiodes. Our results indicate that the GR and the shunt mechanism share the same dependence on bandgap and temperature, i.e., a proportionality to exp(-Eg/2kT).

  7. Status and Progress of a Fault Current Limiting Hts Cable to BE Installed in the con EDISON Grid

    NASA Astrophysics Data System (ADS)

    Maguire, J.; Folts, D.; Yuan, J.; Henderson, N.; Lindsay, D.; Knoll, D.; Rey, C.; Duckworth, R.; Gouge, M.; Wolff, Z.; Kurtz, S.

    2010-04-01

    In the last decade, significant advances in the performance of second generation (2G) high temperature superconducting wire have made it suitable for commercially viable applications such as electric power cables and fault current limiters. Currently, the U.S. Department of Homeland Security is co-funding the design, development and demonstration of an inherently fault current limiting HTS cable under the Hydra project with American Superconductor and Consolidated Edison. The cable will be approximately 300 m long and is being designed to carry 96 MVA at a distribution level voltage of 13.8 kV. The underground cable will be installed and energized in New York City. The project is led by American Superconductor teamed with Con Edison, Ultera (Southwire and nkt cables joint venture), and Air Liquide. This paper describes the general goals, design criteria, status and progress of the project. Fault current limiting has already been demonstrated in 3 m prototype cables, and test results on a 25 m three-phase cable will be presented. An overview of the concept of a fault current limiting cable and the system advantages of this unique type of cable will be described.

  8. The Platte River - High Plains Aquifer (PR-HPA) Long Term Agroecosystem Research (LTAR) Network - Data and Technological Resources to Address Current and Emerging Issues in Agroecosystems.

    NASA Astrophysics Data System (ADS)

    Okalebo, J. A.; Wienhold, B.; Suyker, A.; Erickson, G.; Hayes, M. J.; Awada, T.

    2015-12-01

    The Platte River - High Plains Aquifer (PR-HPA) is one of 18 established Long Term Agroecosystem Research (LTAR) networks across the US. PR-HPA is a partnership between the Institute of Agriculture and Natural Resources at the University of Nebraska-Lincoln (UNL), the USDA-ARS Agroecosystem Management Research Unit (AMRU) in Lincoln, and the USDA-ARS Environmental Management Research Unit (EMRU) in Clay Center, NE. The PR-HPA network encompasses 27,750 ha of research sites with data going back to the early 1900s. A partial list of on-going research projects include those encompassing long-term manuring and continuous corn (Est. 1912), dryland tillage plots (Est. 1970), soil nutrients and tillage (Est. 1983), biofuel feedstock studies (Est. 2001), and carbon sequestration study (Est. 2000). Affiliated partners include the National Drought Mitigation Center (NDMC) that develops measures to improve preparedness and adaptation to climate variability and drought; the High Plains Regional Climate Center (HPRCC) that coordinates data acquisition from over 170 automated weather stations and around 50 automated soil moisture network across NE and beyond; the AMERIFLUX and NEBFLUX networks that coordinate the water vapor and carbon dioxide flux measurements across NE with emphasis on rainfed and irrigated crop lands; the ARS Greenhouse gas Reduction through Agricultural Carbon Enhancement network (GRACEnet) and the Resilient Economic Agricultural Practices (REAP) project; and the Center for Advanced Land Management Information Technologies (CALMIT) that assists with the use of geospatial technologies for agriculture and natural resource applications. Current emphases are on addressing present-day and emerging issues related to profitability and sustainability of agroecosystems. The poster will highlight some of the ongoing and planned efforts in research pertaining to climate variability and change, water sustainability, and ecological and agronomic challenges associated

  9. Climate analogues suggest limited potential for intensification of production on current croplands under climate change

    NASA Astrophysics Data System (ADS)

    Pugh, T. A. M.; Müller, C.; Elliott, J.; Deryng, D.; Folberth, C.; Olin, S.; Schmid, E.; Arneth, A.

    2016-09-01

    Climate change could pose a major challenge to efforts towards strongly increase food production over the coming decades. However, model simulations of future climate-impacts on crop yields differ substantially in the magnitude and even direction of the projected change. Combining observations of current maximum-attainable yield with climate analogues, we provide a complementary method of assessing the effect of climate change on crop yields. Strong reductions in attainable yields of major cereal crops are found across a large fraction of current cropland by 2050. These areas are vulnerable to climate change and have greatly reduced opportunity for agricultural intensification. However, the total land area, including regions not currently used for crops, climatically suitable for high attainable yields of maize, wheat and rice is similar by 2050 to the present-day. Large shifts in land-use patterns and crop choice will likely be necessary to sustain production growth rates and keep pace with demand.

  10. High or low-side solid state relay with current limiting and operational testing

    NASA Astrophysics Data System (ADS)

    Dolland, C. R.

    1984-07-01

    The switch comprises a circuit from a first output terminal via parallel MOS devices in series with current-sensing resistance to a second output terminal, with alternative high-side and low-side configurations having a load between the second terminal and ground, or the first terminal and the DC supply voltage. An input terminal for a digital control signal is coupled via an input diode and two Schmitt Trigger CMOS inverters to a control lead for the gates of the switch. A current overload or short circuit protection circuit coupled between the current-sensor and the input diode comprises two transistors coupled by a diode. A built-in test circuit for indicating the switch condition (on, off, shorted or open) comprises MOS transistors having their gates connected to voltage dividers at the two output terminals, and their drains connected to discrete indication terminals.

  11. Climate analogues suggest limited potential for intensification of production on current croplands under climate change.

    PubMed

    Pugh, T A M; Müller, C; Elliott, J; Deryng, D; Folberth, C; Olin, S; Schmid, E; Arneth, A

    2016-09-20

    Climate change could pose a major challenge to efforts towards strongly increase food production over the coming decades. However, model simulations of future climate-impacts on crop yields differ substantially in the magnitude and even direction of the projected change. Combining observations of current maximum-attainable yield with climate analogues, we provide a complementary method of assessing the effect of climate change on crop yields. Strong reductions in attainable yields of major cereal crops are found across a large fraction of current cropland by 2050. These areas are vulnerable to climate change and have greatly reduced opportunity for agricultural intensification. However, the total land area, including regions not currently used for crops, climatically suitable for high attainable yields of maize, wheat and rice is similar by 2050 to the present-day. Large shifts in land-use patterns and crop choice will likely be necessary to sustain production growth rates and keep pace with demand.

  12. Climate analogues suggest limited potential for intensification of production on current croplands under climate change.

    PubMed

    Pugh, T A M; Müller, C; Elliott, J; Deryng, D; Folberth, C; Olin, S; Schmid, E; Arneth, A

    2016-01-01

    Climate change could pose a major challenge to efforts towards strongly increase food production over the coming decades. However, model simulations of future climate-impacts on crop yields differ substantially in the magnitude and even direction of the projected change. Combining observations of current maximum-attainable yield with climate analogues, we provide a complementary method of assessing the effect of climate change on crop yields. Strong reductions in attainable yields of major cereal crops are found across a large fraction of current cropland by 2050. These areas are vulnerable to climate change and have greatly reduced opportunity for agricultural intensification. However, the total land area, including regions not currently used for crops, climatically suitable for high attainable yields of maize, wheat and rice is similar by 2050 to the present-day. Large shifts in land-use patterns and crop choice will likely be necessary to sustain production growth rates and keep pace with demand. PMID:27646707

  13. 40 CFR 450.21 - Effluent limitations reflecting the best practicable technology currently available (BPT).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... velocity within the site to minimize soil erosion; (2) Control stormwater discharges, including both peak... streambank erosion; (3) Minimize the amount of soil exposed during construction activity; (4) Minimize the... the best practicable technology currently available (BPT). Except as provided in 40 CFR 125.30...

  14. 40 CFR 450.21 - Effluent limitations reflecting the best practicable technology currently available (BPT).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... velocity within the site to minimize soil erosion; (2) Control stormwater discharges, including both peak... streambank erosion; (3) Minimize the amount of soil exposed during construction activity; (4) Minimize the... the best practicable technology currently available (BPT). Except as provided in 40 CFR 125.30...

  15. College Carrier Current: A Survey of 208 Campus-Limited Radio Stations.

    ERIC Educational Resources Information Center

    Broadcast Inst. of North America, New York, NY.

    The purpose of this survey was to determine the extent to which carrier current radio has become a medium which can link and unify relatively small, well-defined groups in an effective and inexpensive way. The survey focused upon the auspices, structure, affiliation, day-to-day managerial responsibility, and administrative liaison of the stations;…

  16. Analysis of Longitudinal Beam Dynamics Behavior and RF System Operative Limits at High Beam Currents in Storage Rings

    SciTech Connect

    Mastorides, T; Rivetta, C.; Fox, J.D.; Winkle, D.Van; Tytelman, D.; /Dimtel, Redwood City

    2008-07-07

    A dynamics simulation model is used to estimate limits of performance of the Positron-Electron Project (PEP-II). The simulation captures the dynamics and technical limitations of the Low Level Radio Frequency (LLRF) system, the high-power RF components and the low-order mode coupled bunch longitudinal beam dynamics. Simulation results showing the effect of non-linearities on the LLRF loops, and studies of the effectiveness of technical component upgrades are reported, as well as a comparison of these results with PEP-II measurements. These studies have led to the estimation of limits and determining factors in the maximum stored current that the Low Energy Ring/High Energy Ring (LER/HER) can achieve, based on system stability for different RF station configurations and upgrades. In particular, the feasibility of the PEP-II plans to achieve the final goal in luminosity, which required an increase of the beam currents to 4A for LER and 2.2A for HER, is studied. These currents are challenging in part because they would push the longitudinal low-order beam mode stability to the limit, and the klystron forward power past a level of satisfactory margin. An acceptable margin is defined in this paper, which in turn determines the corresponding klystron forward power limitation.

  17. Limitations of Focussing on Homophobic, Biphobic and Transphobic "Bullying" to Understand and Address LGBT Young People's Experiences within and beyond School

    ERIC Educational Resources Information Center

    Formby, Eleanor

    2015-01-01

    This paper presents new empirical data that highlight how a focus on "bullying" is too limited and narrow when thinking about homophobia, biphobia and transphobia that young people may experience. The paper draws on two recent studies with young lesbian, gay, bisexual and trans participants, which each identified issues and experiences…

  18. Excess currents larger than the point contact limit in normal-metal/superconducting junctions

    NASA Astrophysics Data System (ADS)

    Riedel, Richard; Bagwell, Philip F.

    1999-05-01

    In a point contact NS junction, perfect Andreev reflection occurs over a range of voltages equal to the superconducting energy gap, producing an excess current of Iexc = (4 / 3)(2 eΔ / h). If the superconductor has a finite width, rather than the infinite width of the point contact, one cannot neglect superfluid flow inside the superconducting contact. The energy range available for perfect Andreev reflections then becomes larger than the superconducting gap, since superfluid flow alters the dispersion relation inside the finite width superconductor. We find a maximum excess current of approximately (7 / 3)(2 eΔ / h) when the width of the superconductor is approximately 7 / 3 times the width of the normal metal.

  19. Opening Address

    NASA Astrophysics Data System (ADS)

    Yamada, T.

    2014-12-01

    Ladies and Gentlemen, it is my great honor and pleasure to present an opening address of the 3rd International Workshop on "State of the Art in Nuclear Cluster Physics"(SOTANCP3). On the behalf of the organizing committee, I certainly welcome all your visits to KGU Kannai Media Center belonging to Kanto Gakuin University, and stay in Yokohama. In particular, to whom come from abroad more than 17 countries, I would appreciate your participations after long long trips from your homeland to Yokohama. The first international workshop on "State of the Art in Nuclear Cluster Physics", called SOTANCP, was held in Strasbourg, France, in 2008, and the second one was held in Brussels, Belgium, in 2010. Then the third workshop is now held in Yokohama. In this period, we had the traditional 10th cluster conference in Debrecen, Hungary, in 2012. Thus we have the traditional cluster conference and SOTANCP, one after another, every two years. This obviously shows our field of nuclear cluster physics is very active and flourishing. It is for the first time in about 10 years to hold the international workshop on nuclear cluster physics in Japan, because the last cluster conference held in Japan was in Nara in 2003, about 10 years ago. The president in Nara conference was Prof. K. Ikeda, and the chairpersons were Prof. H. Horiuchi and Prof. I. Tanihata. I think, quite a lot of persons in this room had participated at the Nara conference. Since then, about ten years passed. So, this workshop has profound significance for our Japanese colleagues. The subjects of this workshop are to discuss "the state of the art in nuclear cluster physics" and also discuss the prospect of this field. In a couple of years, we saw significant progresses of this field both in theory and in experiment, which have brought better and new understandings on the clustering aspects in stable and unstable nuclei. I think, the concept of clustering has been more important than ever. This is true also in the

  20. Convocation address.

    PubMed

    Ghatowar, P S

    1993-07-01

    The Union Deputy Minister of Health and Family Welfare in India addressed the 35th convocation of the International Institute for Population Sciences in Bombay in 1993. Officials in developing countries have been concerned about population growth for more than 30 years and have instituted policies to reduce population growth. In the 1960s, population growth in developing countries was around 2.5%, but today it is about 2%. Despite this decline, the world will have 1 billion more individuals by the year 2001. 95% of these new people will be born in developing countries. India's population size is so great that India does not have the time to wait for development to reduce population growth. Population needs to be viewed as an integrated part of overall development, since it is linked to poverty, illiteracy, environmental damage, gender issues, and reproductive health. Despite a large population size, India has made some important advancements in health and family planning. For example, India has reduced population growth (to 2.14% annually between 1981-1991), infant mortality, and its birth rate. It has increased the contraceptive use rate and life expectancy. Its southern states have been more successful at achieving demographic goals than have the northern states. India needs to implement efforts to improve living conditions, to change attitudes and perceptions about small families and contraception, and to promote family planning acceptance earlier among young couples. Improvement of living conditions is especially important in India, since almost 33% of the people live in poverty. India needs to invest in nutrition, health, and education. The mass media and nongovernmental organizations need to create population awareness and demand for family planning services. Improvement in women's status accelerates fertility decline, as has happened in Kerala State. The government needs to facilitate generation of jobs. Community participation is needed for India to achieve

  1. Minimum current principle and variational method in theory of space charge limited flow

    SciTech Connect

    Rokhlenko, A.

    2015-10-21

    In spirit of the principle of least action, which means that when a perturbation is applied to a physical system, its reaction is such that it modifies its state to “agree” with the perturbation by “minimal” change of its initial state. In particular, the electron field emission should produce the minimum current consistent with boundary conditions. It can be found theoretically by solving corresponding equations using different techniques. We apply here the variational method for the current calculation, which can be quite effective even when involving a short set of trial functions. The approach to a better result can be monitored by the total current that should decrease when we on the right track. Here, we present only an illustration for simple geometries of devices with the electron flow. The development of these methods can be useful when the emitter and/or anode shapes make difficult the use of standard approaches. Though direct numerical calculations including particle-in-cell technique are very effective, but theoretical calculations can provide an important insight for understanding general features of flow formation and even sometimes be realized by simpler routines.

  2. Dispersal limitation drives successional pathways in Central Siberian forests under current and intensified fire regimes.

    PubMed

    Tautenhahn, Susanne; Lichstein, Jeremy W; Jung, Martin; Kattge, Jens; Bohlman, Stephanie A; Heilmeier, Hermann; Prokushkin, Anatoly; Kahl, Anja; Wirth, Christian

    2016-06-01

    Fire is a primary driver of boreal forest dynamics. Intensifying fire regimes due to climate change may cause a shift in boreal forest composition toward reduced dominance of conifers and greater abundance of deciduous hardwoods, with potential biogeochemical and biophysical feedbacks to regional and global climate. This shift has already been observed in some North American boreal forests and has been attributed to changes in site conditions. However, it is unknown if the mechanisms controlling fire-induced changes in deciduous hardwood cover are similar among different boreal forests, which differ in the ecological traits of the dominant tree species. To better understand the consequences of intensifying fire regimes in boreal forests, we studied postfire regeneration in five burns in the Central Siberian dark taiga, a vast but poorly studied boreal region. We combined field measurements, dendrochronological analysis, and seed-source maps derived from high-resolution satellite images to quantify the importance of site conditions (e.g., organic layer depth) vs. seed availability in shaping postfire regeneration. We show that dispersal limitation of evergreen conifers was the main factor determining postfire regeneration composition and density. Site conditions had significant but weaker effects. We used information on postfire regeneration to develop a classification scheme for successional pathways, representing the dominance of deciduous hardwoods vs. evergreen conifers at different successional stages. We estimated the spatial distribution of different successional pathways under alternative fire regime scenarios. Under intensified fire regimes, dispersal limitation of evergreen conifers is predicted to become more severe, primarily due to reduced abundance of surviving seed sources within burned areas. Increased dispersal limitation of evergreen conifers, in turn, is predicted to increase the prevalence of successional pathways dominated by deciduous hardwoods

  3. Dispersal limitation drives successional pathways in Central Siberian forests under current and intensified fire regimes.

    PubMed

    Tautenhahn, Susanne; Lichstein, Jeremy W; Jung, Martin; Kattge, Jens; Bohlman, Stephanie A; Heilmeier, Hermann; Prokushkin, Anatoly; Kahl, Anja; Wirth, Christian

    2016-06-01

    Fire is a primary driver of boreal forest dynamics. Intensifying fire regimes due to climate change may cause a shift in boreal forest composition toward reduced dominance of conifers and greater abundance of deciduous hardwoods, with potential biogeochemical and biophysical feedbacks to regional and global climate. This shift has already been observed in some North American boreal forests and has been attributed to changes in site conditions. However, it is unknown if the mechanisms controlling fire-induced changes in deciduous hardwood cover are similar among different boreal forests, which differ in the ecological traits of the dominant tree species. To better understand the consequences of intensifying fire regimes in boreal forests, we studied postfire regeneration in five burns in the Central Siberian dark taiga, a vast but poorly studied boreal region. We combined field measurements, dendrochronological analysis, and seed-source maps derived from high-resolution satellite images to quantify the importance of site conditions (e.g., organic layer depth) vs. seed availability in shaping postfire regeneration. We show that dispersal limitation of evergreen conifers was the main factor determining postfire regeneration composition and density. Site conditions had significant but weaker effects. We used information on postfire regeneration to develop a classification scheme for successional pathways, representing the dominance of deciduous hardwoods vs. evergreen conifers at different successional stages. We estimated the spatial distribution of different successional pathways under alternative fire regime scenarios. Under intensified fire regimes, dispersal limitation of evergreen conifers is predicted to become more severe, primarily due to reduced abundance of surviving seed sources within burned areas. Increased dispersal limitation of evergreen conifers, in turn, is predicted to increase the prevalence of successional pathways dominated by deciduous hardwoods

  4. Multiple Transportable Carbohydrates During Exercise: Current Limitations and Directions for Future Research.

    PubMed

    Wilson, Patrick B

    2015-07-01

    The concept of multiple transportable carbohydrates (MTC) refers to a combination of saccharides that rely on distinct transporters for intestinal absorption. Ingestion of MTC during prolonged exercise has been purported to increase carbohydrate absorption efficiency, increase exogenous carbohydrate oxidation, reduce gastrointestinal (GI) distress, and improve athletic performance when carbohydrate intake is high (>50-60 g·h⁻¹). Although reviews of MTC research have been published previously, a comprehensive literature evaluation underscoring methodological limitations has not been conducted to guide future work. Accordingly, this review outlined the plausible mechanisms of MTC and subsequently evaluated MTC research based on several factors, including participant characteristics, exercise modality, exercise task, treatment formulation, treatment blinding, and pre-exercise nutrition status. A total of 27 articles examining MTC during exercise were identified and reviewed. Overall, ingestion of MTC led to increased exogenous carbohydrate oxidation, reduced GI distress, and improved performance during cycling lasting ≥2.5 hours, particularly when carbohydrate was ingested at ≥1.2 g·min⁻¹. Despite the apparent benefits, several limitations in the literature were apparent, including that only 3 studies used running, only 2 studies were conducted in the field, most participants were fasted, and women and adolescents were underrepresented. In addition, the majority of the studies fed carbohydrate at ≥1.2 g·min⁻¹, which may have inflated levels of GI distress and exaggerated performance decrements with single-saccharide feedings. Based on these limitations, future MTC investigations should consider focusing on running, examining team-based sports, including women and adolescents, conducting experiments under field conditions, examining the modifying effects of pre-exercise nutrition, and using modest feeding protocols (1.0-1.2 g·min⁻¹).

  5. Diagnosis of viral gastroenteritis: limits and potential of currently available procedures.

    PubMed

    Sidoti, Francesca; Rittà, Massimo; Costa, Cristina; Cavallo, Rossana

    2015-06-01

    The diagnostic approaches to viral gastroenteritis have evolved substantially over the past decades because of the advances in detection methods, the emergence of new pathogens, and the increase in diarrhea hospitalizations attributed to viruses, especially in young children in non-industrialized countries. Overall, these factors have lead to a relevant improvement of types and operating characteristics of diagnostic methods (including sensitivity and specificity), as well as turnaround time. In this review, clinical and laboratory approaches to the diagnosis of viruses causing gastroenteritis are presented; in particular, specimen collection and detection methods are reviewed and discussed, taking into account performance and limitations.

  6. Viral hepatitis in resource-limited countries and access to antiviral therapies: current and future challenges

    PubMed Central

    Lemoine, Maud; Nayagam, Shevanthi; Thursz, Mark

    2013-01-01

    Chronic viral hepatitis is a major public health issue worldwide and mostly affects resource-limited countries. These regions combine a considerable set of barriers to containing the epidemic, including shortage of healthcare workers, poor medical infrastructures, insufficient screening and poor access to care and treatment. At a time when morbidity and mortality of chronic liver disease has been widely improved in wealthy countries by new innovative strategies and potent antiviral drugs, it is now urgent to face the challenges of better management of chronic hepatitis in resource-poor countries from the perspectives of global health and social justice. PMID:23662157

  7. Comparative study of superconducting fault current limiter both for LCC-HVDC and VSC-HVDC systems

    NASA Astrophysics Data System (ADS)

    Lee, Jong-Geon; Khan, Umer Amir; Lim, Sung-Woo; Shin, Woo-ju; Seo, In-Jin; Lee, Bang-Wook

    2015-11-01

    High Voltage Direct Current (HVDC) system has been evaluated as the optimum solution for the renewable energy transmission and long-distance power grid connections. In spite of the various advantages of HVDC system, it still has been regarded as an unreliable system compared to AC system due to its vulnerable characteristics on the power system fault. Furthermore, unlike AC system, optimum protection and switching device has not been fully developed yet. Therefore, in order to enhance the reliability of the HVDC systems mitigation of power system fault and reliable fault current limiting and switching devices should be developed. In this paper, in order to mitigate HVDC fault, both for Line Commutated Converter HVDC (LCC-HVDC) and Voltage Source Converter HVDC (VSC-HVDC) system, an application of resistive superconducting fault current limiter which has been known as optimum solution to cope with the power system fault was considered. Firstly, simulation models for two types of LCC-HVDC and VSC-HVDC system which has point to point connection model were developed. From the designed model, fault current characteristics of faulty condition were analyzed. Second, application of SFCL on each types of HVDC system and comparative study of modified fault current characteristics were analyzed. Consequently, it was deduced that an application of AC-SFCL on LCC-HVDC system with point to point connection was desirable solution to mitigate the fault current stresses and to prevent commutation failure in HVDC electric power system interconnected with AC grid.

  8. Reaching the Ionic Current Detection Limit in Silicon-Based Nanopores

    NASA Astrophysics Data System (ADS)

    Puster, Matthew; Rodriguez-Manzo, Julio Alejandro; Nicolai, Adrien; Meunier, Vincent; Drndic, Marija

    2015-03-01

    Solid-state nanopores act as single-molecule sensors whereby passage of an individual molecule in aqueous electrolyte through a nanopore is registered as a change in ionic conductance (ΔG). Future nanopore applications such as DNA sequencing at high bandwidth require high ΔG for optimal signal-to-noise ratio. Reducing the nanopore diameter and thickness increase ΔG. Molecule size limits the diameter, thus efforts concentrate on minimizing the thickness by thinning oxide/nitride films or using 2D materials. Weighted by electrolyte conductivity the highest ΔG reported to date for DNA translocations were obtained with nanopores made in oxide/nitride films. We present a controlled electron irradiation technique to thin such films to the limit of their stability, producing nanopores tailored to molecule size in amorphous Si with thicknesses less than 2 nm. We compare ΔG values with results found in the literature for DNA translocation through these nanopores, where access resistance becomes comparable to the resistance through the nanopore itself.

  9. Developing Low-Conductance Window Frames: Capabilities and Limitations of Current Window Heat Transfer Design Tools

    SciTech Connect

    Gustavsen, Arild; Arasteh, Dariush; Jelle, Bjorn Petter; Curcija, Charlie; Kohler, Christian

    2008-09-11

    While window frames typically represent 20-30% of the overall window area, their impact on the total window heat transfer rates may be much larger. This effect is even greater in low-conductance (highly insulating) windows that incorporate very low-conductance glazing. Developing low-conductance window frames requires accurate simulation tools for product research and development. Based on a literature review and an evaluation of current methods of modeling heat transfer through window frames, we conclude that current procedures specified in ISO standards are not sufficiently adequate for accurately evaluating heat transfer through the low-conductance frames. We conclude that the near-term priorities for improving the modeling of heat transfer through low-conductance frames are: (1) Add 2D view-factor radiation to standard modeling and examine the current practice of averaging surface emissivity based on area weighting and the process of making an equivalent rectangular frame cavity. (2) Asses 3D radiation effects in frame cavities and develop recommendation for inclusion into the design fenestration tools. (3) Assess existing correlations for convection in vertical cavities using CFD. (4) Study 2D and 3D natural convection heat transfer in frame cavities for cavities that are proven to be deficient from item 3 above. Recommend improved correlations or full CFD modeling into ISO standards and design fenestration tools, if appropriate. (5) Study 3D hardware short-circuits and propose methods to ensure that these effects are incorporated into ratings. (6) Study the heat transfer effects of ventilated frame cavities and propose updated correlations.

  10. The impact of antiretroviral therapy in resource-limited settings and current HIV therapeutics.

    PubMed

    Kumarasamy, N

    2016-04-01

    Four million people of the global total of 35 million with HIV infection are from South-East Asia. ART is currently utilized by 15 million people and has led to a dramatic decline in the mortality rate, including those in low- and middle-income countries. A reduction in sexually transmitted HIV and in comorbidities including tuberculosis has also followed. Current recommendations for the initiation of antiretroviral therapy in people who are HIV+ are essentially to initiate ART irrespective of CD4 cell count and clinical stage. The frequency of HIV testing should be culturally specific and based on the HIV incidence in different key populations but phasing in viral load technology in LMIC is an urgent priority and this needs resources and capacity. With the availability of simplified potent ART regimens, persons with HIV now live longer. The recent WHO treatment guidelines recommending routine HIV testing and earlier initiation of treatment should be the stepping stone for ending the AIDS epidemic and to meet the UNAIDS mission of 90*90*90.

  11. Nanofabrication of arrays of silicon field emitters with vertical silicon nanowire current limiters and self-aligned gates

    NASA Astrophysics Data System (ADS)

    Guerrera, S. A.; Akinwande, A. I.

    2016-07-01

    We developed a fabrication process for embedding a dense array (108 cm-2) of high-aspect-ratio silicon nanowires (200 nm diameter and 10 μm tall) in a dielectric matrix and then structured/exposed the tips of the nanowires to form self-aligned gate field emitter arrays using chemical mechanical polishing (CMP). Using this structure, we demonstrated a high current density (100 A cm-2), uniform, and long lifetime (>100 h) silicon field emitter array architecture in which the current emitted by each tip is regulated by the silicon nanowire current limiter connected in series with the tip. Using the current voltage characteristics and with the aid of numerical device models, we estimated the tip radius of our field emission arrays to be ≈4.8 nm, as consistent with the tip radius measured using a scanning electron microscope (SEM).

  12. Nanofabrication of arrays of silicon field emitters with vertical silicon nanowire current limiters and self-aligned gates

    NASA Astrophysics Data System (ADS)

    Guerrera, S. A.; Akinwande, A. I.

    2016-07-01

    We developed a fabrication process for embedding a dense array (108 cm‑2) of high-aspect-ratio silicon nanowires (200 nm diameter and 10 μm tall) in a dielectric matrix and then structured/exposed the tips of the nanowires to form self-aligned gate field emitter arrays using chemical mechanical polishing (CMP). Using this structure, we demonstrated a high current density (100 A cm‑2), uniform, and long lifetime (>100 h) silicon field emitter array architecture in which the current emitted by each tip is regulated by the silicon nanowire current limiter connected in series with the tip. Using the current voltage characteristics and with the aid of numerical device models, we estimated the tip radius of our field emission arrays to be ≈4.8 nm, as consistent with the tip radius measured using a scanning electron microscope (SEM).

  13. Nanofabrication of arrays of silicon field emitters with vertical silicon nanowire current limiters and self-aligned gates.

    PubMed

    Guerrera, S A; Akinwande, A I

    2016-07-22

    We developed a fabrication process for embedding a dense array (10(8) cm(-2)) of high-aspect-ratio silicon nanowires (200 nm diameter and 10 μm tall) in a dielectric matrix and then structured/exposed the tips of the nanowires to form self-aligned gate field emitter arrays using chemical mechanical polishing (CMP). Using this structure, we demonstrated a high current density (100 A cm(-2)), uniform, and long lifetime (>100 h) silicon field emitter array architecture in which the current emitted by each tip is regulated by the silicon nanowire current limiter connected in series with the tip. Using the current voltage characteristics and with the aid of numerical device models, we estimated the tip radius of our field emission arrays to be ≈4.8 nm, as consistent with the tip radius measured using a scanning electron microscope (SEM). PMID:27292120

  14. Reversible stress and strain limits of the critical current of practical REBCO and BSCCO wires

    NASA Astrophysics Data System (ADS)

    Osamura, K.; Machiya, S.; Nishijima, G.

    2016-09-01

    Practical REBCO and BSCCO-2223 tape-shaped wires are now manufactured on an industrial scale. They are a typical composite material consisting of superconducting layer/filaments together with functional components. These functional components affect directly the stress and strain dependences of the critical current. When applying an external stress R, the critical current I c was measured. Then the external stress was reduced to R = 0 and the recovered critical current I cr was again measured. The tensile stress and strain dependences of both normalized critical currents divided by the original value, I c/I c0 and I cr/I c0 were investigated. In general I cr/I c0 recovered close to unity when the applied stress was low, but its recovering level decreased gradually with increasing applied stress. The definition of the reversible stress and strain limits was investigated and its validity was proved using the cyclic loading test. The original definition of reversible stress and strain limits of critical current relates to: (1) when releasing the applied stress and strain, the I c shall recover to the original value, and (2) when applying the cyclic stresses, the I c shall keep the original value. Here, as a practical definition for the reversible stress and strain limits, the tensile stress and strain at 99% recovery of I c have been proposed. On the other hand, it was made clear that the stress and strain at I c 95% retention are not valid for use commonly as a criterion of reversible stress and strain limits for both practical REBCO and BSCCO-2223 wires.

  15. Effect of water availability on leaf water isotopic enrichment in beech seedlings shows limitations of current fractionation models.

    PubMed

    Ferrio, Juan Pedro; Cuntz, Matthias; Offermann, Christine; Siegwolf, Rolf; Saurer, Matthias; Gessler, Arthur

    2009-10-01

    Current models of leaf water enrichment predict that the differences between isotopic enrichment of water at the site of evaporation (Delta(e)) and mean lamina leaf water enrichment (Delta(L)) depend on transpiration rates (E), modulated by the scaled effective length (L) of water isotope movement in the leaf. However, variations in leaf parameters in response to changing environmental conditions might cause changes in the water path and thus L. We measured the diel course of Delta(L) for (18)O and (2)H in beech seedlings under well-watered and water-limited conditions. We applied evaporative enrichment models of increasing complexity to predict Delta(e) and Delta(L), and estimated L from model fits. Water-limited plants showed moderate drought stress, with lower stomatal conductance, E and stem water potential than the control. Despite having double E, the divergence between Delta(e) and Delta(L) was lower in well-watered than in water-limited plants, and thus, L should have changed to counteract differences in E. Indeed, L was about threefold higher in water-limited plants, regardless of the models used. We conclude that L changes with plant water status far beyond the variations explained by water content and other measured variables, thus limiting the use of current evaporative models under changing environmental conditions. PMID:19453484

  16. Invited review current progress and limitations of spider silk for biomedical applications.

    PubMed

    Widhe, Mona; Johansson, Jan; Hedhammar, My; Rising, Anna

    2012-06-01

    Spider silk is a fascinating material combining remarkable mechanical properties with low density and biodegradability. Because of these properties and historical descriptions of medical applications, spider silk has been proposed to be the ideal biomaterial. However, overcoming the obstacles to produce spider silk in sufficient quantities and in a manner that meets regulatory demands has proven to be a difficult task. Also, there are relatively few studies of spider silk in biomedical applications available, and the methods and materials used vary a lot. Herein we summarize cell culture- and in vivo implantation studies of natural and synthetic spider silk, and also review the current status and future challenges in the quest for a large scale production of spider silk for medical applications. PMID:21898363

  17. Biasing, operation and parasitic current limitation in single device equivalent to CMOS, and other semiconductor systems

    DOEpatents

    Welch, James D.

    2003-09-23

    Disclosed are semiconductor devices including at least one junction which is rectifying whether the semiconductor is caused to be N or P-type, by the presence of applied gate voltage field induced carriers in essentially intrinsic, essentially homogeneously simultaneously containing both N and P-type metallurgical dopants at substantially equal doping levels, essentially homogeneously simultaneously containing both N and P-type metallurgical dopants at different doping levels, and containing a single metallurgical doping type, and functional combinations thereof. In particular, inverting and non-inverting gate voltage channel induced semiconductor single devices with operating characteristics similar to conventional multiple device CMOS systems, which can be operated as modulators, are disclosed as are a non-latching SCR and an approach to blocking parasitic currents utilizing material(s) which form rectifying junctions with both N and P-type semiconductor whether metallurigically or field induced.

  18. [Exchange of medical imaging and data information in radiotherapy: needs, methods and current limits].

    PubMed

    Manens, J P

    1997-01-01

    Extension of the image network within radiotherapy departments provides the technical infrastructure which is made necessary by the rapid evolution of techniques in the field of diagnosis and treatment in radiotherapy. The system is aimed at managing the whole set of data (textual data and images) that are needed for planning and control of treatments. The radiotherapy network addresses two objectives: managing both the information necessary for treatment planning (target volumes definition, planning dosimetry) and the control of all parameters involved during the patient's treatment under the treatment unit. The major challenge is to improve the quality of treatment. Multimodal imaging is a major advance as it allows the use of new dosimetry and simulation techniques. The need for standards to exchange medical imaging information is now recognized by all the institutions and a majority of users and manufacturers. It is widely accepted that the lack of standard has been one of the fundamental obstacles in the deployment of operational "Picture Archiving Communication Systems". The International Standard Organisation Open System Interconnection model is the standard reference mode used to describe network protocols. The network is based on the Ethernet and TCP/IP protocol that provides the means to interconnect imaging devices and workstations dedicated to specific image processing or machines used in radiotherapy. The network uses Ethernet cabled on twisted-pair (10 BaseT) or optical fibres in a star-shaped physical layout. Dicom V3.0 supports fundamental network interactions: transfer of images (computerized tomography magnetic resonance imaging query and retrieve of images), printing on network attached cameras, support of HIS/RIS related interfacing and image management. The supplement to the Dicom standard, Dicom RT, specifies five data objects known in Dicom as Information Object Definition for relevant radiotherapy. Dicom RT objects can provide a mean for

  19. [Exchange of medical imaging and data information in radiotherapy: needs, methods and current limits].

    PubMed

    Manens, J P

    1997-01-01

    Extension of the image network within radiotherapy departments provides the technical infrastructure which is made necessary by the rapid evolution of techniques in the field of diagnosis and treatment in radiotherapy. The system is aimed at managing the whole set of data (textual data and images) that are needed for planning and control of treatments. The radiotherapy network addresses two objectives: managing both the information necessary for treatment planning (target volumes definition, planning dosimetry) and the control of all parameters involved during the patient's treatment under the treatment unit. The major challenge is to improve the quality of treatment. Multimodal imaging is a major advance as it allows the use of new dosimetry and simulation techniques. The need for standards to exchange medical imaging information is now recognized by all the institutions and a majority of users and manufacturers. It is widely accepted that the lack of standard has been one of the fundamental obstacles in the deployment of operational "Picture Archiving Communication Systems". The International Standard Organisation Open System Interconnection model is the standard reference mode used to describe network protocols. The network is based on the Ethernet and TCP/IP protocol that provides the means to interconnect imaging devices and workstations dedicated to specific image processing or machines used in radiotherapy. The network uses Ethernet cabled on twisted-pair (10 BaseT) or optical fibres in a star-shaped physical layout. Dicom V3.0 supports fundamental network interactions: transfer of images (computerized tomography magnetic resonance imaging query and retrieve of images), printing on network attached cameras, support of HIS/RIS related interfacing and image management. The supplement to the Dicom standard, Dicom RT, specifies five data objects known in Dicom as Information Object Definition for relevant radiotherapy. Dicom RT objects can provide a mean for

  20. FDG-PET for hepatobiliary and pancreatic cancer: Advances and current limitations.

    PubMed

    Murakami, Koji

    2011-05-10

    In Japan, the use of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for some malignant tumors came to be covered by the National Health Insurance in 2002. In 2010, the health insurance coverage was expanded to all types of malignant tumors. However, since PET examination requires a large amount of capital investment, facilities at which PET is available are still limited. On the other hand, PET equipment has rapidly been introduced in large hospitals and in the diagnostic imaging centers of major cities during the past few years. Although numerous middle-sized and small hospitals cannot afford to perform PET, physicians can refer their patients to facilities where PET is available. Therefore, it is essential for general physicians to gain accurate knowledge on PET, including the appropriate indications for PET, in order to select patients for referral to PET facilities. PET is not always a useful tool, especially for lesions of the pancreas and hepatobiliary system, which is the main topic of this review. The indications of PET for lesions in these organs vary depending on the purpose of the examination. In this article, we review the indications for PET (or PET/computed tomography [CT]) using FDG of the liver, biliary tract, and pancreas.

  1. Current drugs and drug targets in non-small cell lung cancer: limitations and opportunities.

    PubMed

    Daga, Aditi; Ansari, Afzal; Patel, Shanaya; Mirza, Sheefa; Rawal, Rakesh; Umrania, Valentina

    2015-01-01

    Lung cancer is a serious health problem and leading cause of death worldwide due to its high incidence and mortality. More than 80% of lung cancers feature a non-small cell histology. Over few decades, systemic chemotherapy and surgery are the only treatment options in this type of tumor but due to their limited efficacy and overall poor survival of patients, there is an urge to develop newer therapeutic strategies which circumvent the problems. Enhanced knowledge of translational science and molecular biology have revealed that lung tumors carry diverse driver gene mutations and adopt different intracellular pathways leading to carcinogenesis. Hence, the development of targeted agents against molecular subgroups harboring critical mutations is an attractive approach for therapeutic treatment. Targeted therapies are clearly more preferred nowadays over systemic therapies because they target tumor specific molecules resulting with enhanced activity and reduced toxicity to normal tissues. Thus, this review encompasses comprehensive updates on targeted therapies for the driver mutations in non-small cell lung cancer (NSCLC) and the potential challenges of acquired drug resistance faced in the field of targeted therapy along with the imminent newer treatment modalities against lung cancer.

  2. Portable monitoring devices in the diagnosis of obstructive sleep apnea: current status, advantages, and limitations.

    PubMed

    Polese, Jéssica Fábia; Santos-Silva, Rogério; Kobayashi, Rafael Freire; Pinto, Indira Nunes de Paula; Tufik, Sérgio; Bittencourt, Lia Rita Azeredo

    2010-01-01

    Recent years have seen a growing interest in the use of portable monitoring devices for the diagnosis of obstructive sleep apnea syndrome. These have the potential to be used in lieu of the more complicated and uncomfortable alternative, polysomnography, which has long been considered to be the gold standard for the diagnosis of this relatively prevalent condition. Following their approval in 2008 by the Center of Medicare and Medicaid Services, the federal agency which administers Medicare and Medicaid in the United States, there has been extensive discussion about the utility and validity of these devices for use in the diagnosis of obstructive sleep apnea syndrome. Although there are various models of portable monitoring devices, the literature contains little information regarding how each device should be used in specific age groups, patients presenting comorbidities, and asymptomatic patients. Additionally, studies about the cost-effectiveness of this diagnostic method are scarce and conflicting. Therefore, this objective of this study was to review what has been learned about portable monitoring devices over time, as well as to examine the recent progress, advantages, limitations, and applications of these devices in the diagnosis of obstructive sleep apnea syndrome in different groups of patients.

  3. Dissipated energy as a design parameter of coated conductors for their use in resistive fault current limiters

    NASA Astrophysics Data System (ADS)

    Schacherer, C.; Kudymow, A.; Noe, M.

    2008-02-01

    Coated conductors are suitable for many power applications like motors, magnets and superconducting fault current limiters (SCFCLs). For their use in resistive SCFCLs main requirements are quench stability and resistance development above Tc. Several coated conductors are available with different kinds of stabilization like thickness or material of cap-layer and additional stabilization. The stabilization can vary and has a great influence on the quench stability and quench behaviour of a coated conductor. Thus, for the dimensioning of a superconducting current limiting element there is a need of reliable and universal design parameters. This paper presents experimental quench test results on several coated conductor types with different stabilization and geometry. The test results show that the dissipated energy during a quench is a very useful parameter for the SCFCL design.

  4. Semi-empirical equation of limiting current for cobalt electrodeposition in the presence of magnetic field and additive electrolyte

    NASA Astrophysics Data System (ADS)

    Sudibyo, Aziz, N.

    2016-02-01

    One of the available methods to solve a roughening in cobalt electrodeposition is magneto electrodeposition (MED) in the presence of additive electrolyte. Semi-empirical equation of limiting current under a magnetic field for cobalt MED in the presence of boric acid as an additive electrolyte was successfully developed. This semi empirical equation shows the effects of the electrode area (A), the concentration of the electro active species (C), the diffusion coefficient of the electro active species (D), the kinematic viscosity of the electrolyte (v), magnetic strength (B) and the number of electrons involved in the redox process (n). The presence of boric acid led to decrease in the limiting current, but the acid was found useful as a buffer to avoid the local pH rise caused by parallel hydrogen evolution reaction (HER).

  5. Joint operation of the superconducting fault current limiter and magnetic energy storage system in an electric power network

    NASA Astrophysics Data System (ADS)

    Kopylov, S. I.; Balashov, N. N.; Ivanov, S. S.; Veselovsky, A. S.; Zhemerikin, V. D.

    2010-06-01

    An opportunity of using superconductors as active elements of electric power systems designed to control the electric power distribution, to enhance the systems operating modes and to limit fault currents, was very attractive for investigators for a long time. In this paper, is considered an opportunity to enhance the electric power systems with the aid of superconducting magnetic energy storage systems (SMES) and superconducting fault current limiters (SFCL) operating together. It has been shown that the joint operation of both these superconducting devices allows additional varying of their parameters, what in turn gives a further opportunity to reduce their mass and dimensions and consequently the costs. There had been also shown an additional advantage of the SMES and SFCL joint operation consisting in that they ensure a more effective protection for a power system, preventing its uncontrolled load-off and subsequent acceleration up to the inaccessible rotation speed.

  6. Patterning with amorphous carbon spacer for expanding the resolution limit of current lithography tool

    NASA Astrophysics Data System (ADS)

    Jung, Woo-Yung; Kim, Sang-Min; Kim, Choi-Dong; Sim, Guee-Hwang; Jeon, Sung-Min; Park, Sang-Wook; Lee, Byung-Seok; Park, Sung-Ki; Kim, Ji-Soo; Heon, Lee-Sang

    2007-03-01

    Double patterning technique using spacer which can avoid CD (Critical Dimension) uniformity problem mainly caused by overlay issue is one of the methods that could be applied to apply to manufacturing of memory devices. Though double exposure and etch technology (DEET) has comparative advantage in the number of process steps, it is required to dramatically improve overlay performance of current exposure tools for the realization of manufacturing. In this study, negative type-double pattering technique using spacer has been developed as the best way for the application of NAND flash memory device from the view point of CD uniformity and the number of mask layers used to complete double patterning. Negative type-double patterning technique using spacer consists of subsequent steps such as formation of poly line, spacer on sidewall of poly line, SOG gap fill into space between poly lines, SOG etch back, removal of spacer, and finally hard mask etch. We have used amorphous carbon as a spacer material to easily remove spacer from poly lines and adopted SOG material to easily fill in space between poly lines. When negative type-double patterning technique using spacer is applied to NAND flash memory device, we can expect that k1 factor of about 0.14~0.20 could be accomplished successfully.

  7. Incorporating cumulative effects into environmental assessments of mariculture: Limitations and failures of current siting methods

    SciTech Connect

    King, Sarah C. Pushchak, Ronald

    2008-11-15

    Assessing and evaluating the cumulative impacts of multiple marine aquaculture facilities has proved difficult in environmental assessment. A retrospective review of 23 existing mariculture farms in southwestern New Brunswick was conducted to determine whether cumulative interactions would have justified site approvals. Based on current scientific evidence of cumulative effects, six new criteria were added to a set of far-field impacts and other existing criteria were expanded to include regional and cumulative environmental impacts in Hargrave's [Hargrave BT. A traffic light decision system for marine finfish aquaculture siting. Ocean Coast Manag 2002; 45:215-35.] Traffic Light Decision Support System (DSS) presently used in Canadian aquaculture environmental assessments. Before mitigation, 19 of the 23 sites failed the amended set of criteria and after considering mitigation, 8 sites failed. Site and ecosystem indices yielded varying site acceptability scores; however, many sites would not have been approved if siting decisions had been made within a regional management framework and cumulative impact criteria were considered in the site evaluation process.

  8. Formulation approaches to pediatric oral drug delivery: benefits and limitations of current platforms

    PubMed Central

    Lopez, Felipe L; Ernest, Terry B; Tuleu, Catherine; Gul, Mine Orlu

    2015-01-01

    Introduction: Most conventional drug delivery systems are not acceptable for pediatric patients as they differ in their developmental status and dosing requirements from other subsets of the population. Technology platforms are required to aid the development of age-appropriate medicines to maximize patient acceptability while maintaining safety, efficacy, accessibility and affordability. Areas covered: The current approaches and novel developments in the field of age-appropriate drug delivery for pediatric patients are critically discussed including patient-centric formulations, administration devices and packaging systems. Expert opinion: Despite the incentives provided by recent regulatory modifications and the efforts of formulation scientists, there is still a need for implementation of pharmaceutical technologies that enable the manufacture of licensed age-appropriate formulations. Harmonization of endeavors from regulators, industry and academia by sharing learning associated with data obtained from pediatric investigation plans, product development pathways and scientific projects would be the way forward to speed up bench-to-market age appropriate formulation development. A collaborative approach will benefit not only pediatrics, but other patient populations such as geriatrics would also benefit from an accelerated patient-centric approach to drug delivery. PMID:26165848

  9. Current clinical therapies for cartilage repair, their limitation and the role of stem cells.

    PubMed

    Dhinsa, Baljinder S; Adesida, Adetola B

    2012-03-01

    The management of osteochondral defects of articular cartilage, whether from trauma or degenerative disease, continues to be a significant challenge for Orthopaedic surgeons. Current treatment options such as abrasion arthroplasty procedures, osteochondral transplantation and autologous chondrocyte implantation fail to produce repair tissue exhibiting the same mechanical and functional properties of native articular cartilage. This results in repair tissue that inevitably fails as it is unable to deal with the mechanical demands of articular cartilage, and does not prevent further degeneration of the native cartilage. Mesenchymal stem cells have been proposed as a potential source of cells for cell-based cartilage repair due to their ability to self-renew and undergo multi-lineage differentiation. This proposed procedure has the advantage of not requiring harvesting of cells from the joint surface, and its associated donor site morbidity, as well as having multiple possible adult donor tissues such as bone marrow, adipose tissue and synovium. Mesenchymal stem cells have multi-lineage potential, but can be stimulated to undergo chondrogenesis in the appropriate culture medium. As the majority of work with mesenchymal stem cell-derived articular cartilage repair has been carried out in vitro and in animal studies, more work still has to be done before this technique can be used for clinical purposes. This includes realizing the ideal method of harvesting mesenchymal stem cells, the culture medium to stimulate proliferation and differentiation, appropriate choice of scaffold incorporating growth factors directly or with gene therapy and integration of repair tissue with native tissue.

  10. A trap-limited-current-based model of Meyer-Neldel rule and its connection to persistent photocurrent

    NASA Astrophysics Data System (ADS)

    Tian, Ye; Jiang, Lianjun; Zhang, Xuejun; Zhang, Guangfu

    2016-10-01

    A theoretical model is established to describe the emergence of the Meyer-Neldel rule (MNR) based on trap-limited current (TLC) theory. The model produces both MNR and anti-MNR behavior, and is available to various trap distributions. Moreover, TLC-based MNR is connected to persistent photocurrent (PPC) phenomenon. The information from MNR and PPC as well as their connection can be used to probe the distribution of the traps in materials.

  11. Some current problems in perovskite nano-ferroelectrics and multiferroics: kinetically-limited systems of finite lateral size

    NASA Astrophysics Data System (ADS)

    Scott, James F.; Schilling, Alina; Rowley, S. E.; Gregg, J. Marty

    2015-06-01

    We describe some unsolved problems of current interest; these involve quantum critical points in ferroelectrics and problems which are not amenable to the usual density functional theory, nor to classical Landau free energy approaches (they are kinetically limited), nor even to the Landau-Kittel relationship for domain size (they do not satisfy the assumption of infinite lateral diameter) because they are dominated by finite aperiodic boundary conditions.

  12. Experimental studies of the quench behaviour of MgB2 superconducting wires for fault current limiter applications

    NASA Astrophysics Data System (ADS)

    Ye, Lin; Majoros, M.; Campbell, A. M.; Coombs, T.; Astill, D.; Harrison, S.; Husband, M.; Rindfleisch, M.; Tomsic, M.

    2007-07-01

    Various MgB2 wires with different sheath materials provided by Hyper Tech Research Inc., have been tested in the superconducting fault current limiter (SFCL) desktop tester at 24-26 K in a self-field. Samples 1 and 2 are similarly fabricated monofilamentary MgB2 wires with a sheath of CuNi, except that sample 2 is doped with SiC and Mg addition. Sample 3 is a CuNi sheathed multifilamentary wire with Cu stabilization and Mg addition. All the samples with Nb barriers have the same diameter of 0.83 mm and superconducting fractions ranging from 15% to 27% of the total cross section. They were heat-treated at temperatures of 700 °C for a hold time of 20-40 min. Current limiting properties of MgB2 wires subjected to pulse overcurrents have been experimentally investigated in an AC environment in the self-field at 50 Hz. The quench currents extracted from the pulse measurements were in a range of 200-328 A for different samples, corresponding to an average engineering critical current density (Je) of around 4.8 × 104 A cm-2 at 25 K in the self-field, based on the 1 µV cm-1 criterion. This work is intended to compare the quench behaviour in the Nb-barrier monofilamentary and multifilamentary MgB2 wires with CuNi and Cu/CuNi sheaths. The experimental results can be applied to the design of fault current limiter applications based on MgB2 wires. This work is supported by Rolls-Royce plc and the UK Department of Trade and Industry (DTI).

  13. Variable addressability imaging systems

    NASA Astrophysics Data System (ADS)

    Kubala, Kenneth Scott

    The use of variable addressability for creating an optimum human-machine interface is investigated. Current wide field optical systems present more information to the human visual system than it has the capacity to perceive. The axial resolution, and/or the field of view can be increased by minimizing the difference between what the eye can perceive and what the system presents. The variable addressability function was developed through the use of a human factors experiment that characterized the position of the eye during the simulated use of a binocular system. Applying the variable addressability function to a conventional optical design required the development of a new metric for evaluating the expected performance of the variable addressability system. The new metric couples psycho-visual data and traditional optical data in order to specify the required performance of the variable addressability system. A non-linear mapping of the pixels is required in order to have the system work most efficiently with the human visual system, while also compensating for eye motion. The non-linear mapping function, which is the backbone of the variable addressability technique, can be created using optical distortion. The lens and system design is demonstrated in two different spectral bands. One of the designs was fabricated, tested, and assembled into a prototype. Through a second human factors study aimed at measuring performance, the variable addressability prototype was directly compared to a uniform addressability prototype, quantifying the difference in performance for the two prototypes. The human factors results showed that the variable addressability prototype provided better resolution 13% of the time throughout the experiment, but was 15% slower in use than the uniform addressability prototype.

  14. A practical approach in substation capacitor bank applications to calculating, limiting, and reducing the effects of transient currents

    SciTech Connect

    Smith, L.M.

    1995-07-01

    When two or more capacitor banks are in parallel on a common bus, the back-to-back switching of a bank against one or more already energized banks can produce high peak transient in-rush current values. Typically, these currents can exceed the available fault current levels previously present at the bus. The presence of inductance and capacitance together makes the transients oscillatory. Because of close circuit coupling, the transient frequency is generally several kilohertz or higher and usually decays to zero in a fraction of a 60-Hz cycle. The relatively high level and short duration of these currents can damage substation and control equipment necessitating that appropriate precautions be taken during the design process. This paper explores the methods for estimating capacitor bank transient currents, based on ANSI/IEEE C37.012-1979, for various sizes, voltages, and configurations of real world capacitor bank installations. Also discussed are the various accepted and applied methods for limiting substation equipment susceptibility to transients, as well as reducing the magnitude of the transients themselves.

  15. Comparison of the volatile emission profiles of ground almond and pistachio mummies: part 1 – addressing a gap in knowledge of current attractants of navel orangeworm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the years various tissues of almond and pistachios have been evaluated for their ability to attract the navel orangeworm moth, a major insect pest to almond and pistachio orchards in California. Almond meal, which typically consists of ground almond kernels, is the current monitoring tool for n...

  16. State of the art of superconducting fault current limiters and their application to the electric power system

    NASA Astrophysics Data System (ADS)

    Morandi, Antonio

    2013-01-01

    Modern electric power systems are becoming more and more complex in order to meet new needs. Nowadays a high power quality is mandatory and there is the need to integrate increasing amounts of on-site generation. All this translates in more sophisticated electric network with intrinsically high short circuit rate. This network is vulnerable in case of fault and special protection apparatus and procedures needs to be developed in order to avoid costly or even irreversible damage. A superconducting fault current limiter (SFCL) is a device with a negligible impedance in normal operating conditions that reliably switches to a high impedance state in case of extra-current. Such a device is able to increase the short circuit power of an electric network and to contemporarily eliminate the hazard during the fault. It can be regarded as a key component for future electric power systems. In this paper the state of the art of superconducting fault current limiters mature for applications is briefly resumed and the potential impact of this device on the paradigm of design and operation of power systems is analyzed. In particular the use of the FCL as a mean to allow more interconnection of MV bus-bars as well an increased immunity with respect to the voltage disturbances induced by critical customer is discussed. The possibility to integrate more distributed generation in the distribution grid is also considered.

  17. Advances In Vertical Solid-State Current Limiters For Individual Field Emitter Regulation In High-Density Arrays

    NASA Astrophysics Data System (ADS)

    Hill, Frances A.; Velásquez-García, Luis F.

    2015-12-01

    We report the design, fabrication, and characterization of improved solid-state elements intended for individual regulation of field emitters part of high-density arrays. We demonstrate a high-yield, CMOS compatible fabrication process of single-crystal, vertical, ungated, n-type silicon field-effect transistors (FETs); each device behaves as a current source when is biased at a voltage larger than its drain-source saturation voltage. An ungated FET in saturation connected in series to a field emitter can compensate for the wide variation in current-voltage characteristics of the field emitters due to the tip radii spread present in any field emitter array, which should result in emitter burn-out protection, larger array utilization, and smaller array emission non-uniformity. Using 1-2 Ωcm single-crystal n-Si wafers, we fabricated arrays of 25 μm tall vertical ungated FETs with 0.5 μm diameter that span two orders of magnitude of array size. Experimental characterization of the arrays demonstrates that the current is limited with > 3.5 V bias voltage to the same ∼6 μA (6 A.cm-2) per-FET value. Finite element simulations of the device predict a saturation voltage close to the experimental value and a saturation current within a factor of two of the experimental value.

  18. Model for Electron-Beam-Induced Current Analysis of mc-Si Addressing Defect Contrast Behavior in Heavily Contaminated PV Material: Preprint

    SciTech Connect

    Guthrey, H.; Gorman, B.; Al-Jassim, M.

    2012-06-01

    Much work has been done to correlate electron-beam-induced current (EBIC) contrast behavior of extended defects with the character and degree of impurity decoration. However, existing models fail to account for recently observed contrast behavior of defects in heavily contaminated mc-Si PV cells. We have observed large increases in defect contrast with decreasing temperature for all electrically active defects, regardless of their initial contrast signatures at ambient temperature. This negates the usefulness of the existing models in identifying defect character and levels of impurity decoration based on the temperature dependence of the contrast behavior. By considering the interactions of transition metal impurities with the silicon lattice and extended defects, we attempt to provide an explanation for these observations. Our findings will enhance the ability of the PV community to understand and mitigate the effects of these types of defects as the adoption of increasingly lower purity feedstocks for mc-Si PV production continues.

  19. Measuring exposure to the polyphenol metabolome in observational epidemiologic studies: current tools and applications and their limits123

    PubMed Central

    Zamora-Ros, Raul; Touillaud, Marina; Rothwell, Joseph A; Romieu, Isabelle; Scalbert, Augustin

    2014-01-01

    Much experimental evidence supports a protective role of dietary polyphenols against chronic diseases such as cardiovascular diseases, diabetes, and cancer. However, results from observational epidemiologic studies are still limited and are often inconsistent. This is largely explained by the difficulties encountered in the estimation of exposure to the polyphenol metabolome, which is composed of ∼500 polyphenols distributed across a wide variety of foods and characterized by diverse biological properties. Exposure to the polyphenol metabolome in epidemiologic studies can be assessed by the use of detailed dietary questionnaires or the measurement of biomarkers of polyphenol intake. The questionnaire approach has been greatly facilitated by the use of new databases on polyphenol composition but is limited by bias as a result of self-reporting. The use of polyphenol biomarkers holds much promise for objective estimation of polyphenol exposure in future metabolome-wide association studies. These approaches are reviewed and their advantages and limitations discussed by using examples of epidemiologic studies on polyphenols and cancer. The current improvement in these techniques, along with greater emphasis on the intake of individual polyphenols rather than polyphenols considered collectively, will help unravel the role of these major food bioactive constituents in disease prevention. PMID:24787490

  20. Normal zone propagation in superconducting thin-film fault current limiting elements with Au-Ag alloy shunt layers

    NASA Astrophysics Data System (ADS)

    Arai, K.; Yamasaki, H.; Kaiho, K.; Furuse, M.; Nakagawa, Y.; Sohma, M.; Yamaguchi, I.

    2008-02-01

    We have been developing a superconducting fault current limiter (FCL), in which YBCO superconducting thin films with Au-Ag alloy shunt layers are used. We have already achieved high electric fields (>40 Vpeak/cm), which enable the total length of FCL elements to be reduced drastically, thus greatly reducing the cost of FCLs. In this paper, we report the normal zone propagation velocity in our films when over-current was applied to the films at 50 Hz for 100 ms. The velocity plotted against the root-mean square values of the normalized film current showed a common curve or curves. The data were also discussed using the adiabatic theory. As the normal zone propagation velocity was not so fast, we divided one unit film of 120 mm length into two portions, to each of which an external resistance was attached. The test result showed that a high electric field of 45 Vpeak/cm and total voltage of 450 Vpeak were achieved in the first cycle after quenching, and the film withstood the voltage for five cycles. The temperature distribution along the length of the film was also shown.

  1. The LLNL High Accuracy Volume Renderer for Unstructured Data: Capabilities, Current Limits, and Potential for ASCI/VIEWS Deployment

    SciTech Connect

    Williams, P L; Max, N L

    2001-06-04

    This report describes a volume rendering system for unstructured data, especially finite element data, that creates images with very high accuracy. The system will currently handle meshes whose cells are either linear or quadratic tetrahedra, or meshes with mixed cell types: tetrahedra, bricks, prisms, and pyramids. The cells may have nonplanar facets. Whenever possible, exact mathematical solutions for the radiance integrals and for interpolation are used. Accurate semitransparent shaded isosurfaces may be embedded in the volume rendering. For very small cells, subpixel accumulation by splatting is used to avoid sampling error. A new exact and efficient visibility ordering algorithm is described. The most accurate images are generated in software, however, more efficient algorithms utilizing graphics hardware may also be selected. The report describes the parallelization of the system for a distributed-shared memory multiprocessor machine, and concludes by discussing the system's limits, desirable future work, and ways to extend the system so as to be compatible with projected ASCI/VIEWS architectures.

  2. Current Treatment Limitations in Age-Related Macular Degeneration and Future Approaches Based on Cell Therapy and Tissue Engineering

    PubMed Central

    Fernández-Robredo, P.; Sancho, A.; Johnen, S.; Recalde, S.; Gama, N.; Thumann, G.; Groll, J.; García-Layana, A.

    2014-01-01

    Age-related macular degeneration (AMD) is the leading cause of blindness in the Western world. With an ageing population, it is anticipated that the number of AMD cases will increase dramatically, making a solution to this debilitating disease an urgent requirement for the socioeconomic future of the European Union and worldwide. The present paper reviews the limitations of the current therapies as well as the socioeconomic impact of the AMD. There is currently no cure available for AMD, and even palliative treatments are rare. Treatment options show several side effects, are of high cost, and only treat the consequence, not the cause of the pathology. For that reason, many options involving cell therapy mainly based on retinal and iris pigment epithelium cells as well as stem cells are being tested. Moreover, tissue engineering strategies to design and manufacture scaffolds to mimic Bruch's membrane are very diverse and under investigation. Both alternative therapies are aimed to prevent and/or cure AMD and are reviewed herein. PMID:24672707

  3. Current treatment limitations in age-related macular degeneration and future approaches based on cell therapy and tissue engineering.

    PubMed

    Fernández-Robredo, P; Sancho, A; Johnen, S; Recalde, S; Gama, N; Thumann, G; Groll, J; García-Layana, A

    2014-01-01

    Age-related macular degeneration (AMD) is the leading cause of blindness in the Western world. With an ageing population, it is anticipated that the number of AMD cases will increase dramatically, making a solution to this debilitating disease an urgent requirement for the socioeconomic future of the European Union and worldwide. The present paper reviews the limitations of the current therapies as well as the socioeconomic impact of the AMD. There is currently no cure available for AMD, and even palliative treatments are rare. Treatment options show several side effects, are of high cost, and only treat the consequence, not the cause of the pathology. For that reason, many options involving cell therapy mainly based on retinal and iris pigment epithelium cells as well as stem cells are being tested. Moreover, tissue engineering strategies to design and manufacture scaffolds to mimic Bruch's membrane are very diverse and under investigation. Both alternative therapies are aimed to prevent and/or cure AMD and are reviewed herein. PMID:24672707

  4. Evaluation of critical current density and residual resistance ratio limits in powder in tube Nb3Sn conductors

    NASA Astrophysics Data System (ADS)

    Segal, Christopher; Tarantini, Chiara; Hawn Sung, Zu; Lee, Peter J.; Sailer, Bernd; Thoener, Manfred; Schlenga, Klaus; Ballarino, Amalia; Bottura, Luca; Bordini, Bernardo; Scheuerlein, Christian; Larbalestier, David C.

    2016-08-01

    High critical current density (J c) Nb3Sn A15 multifilamentary wires require a large volume fraction of small grain (SG), superconducting A15 phase, as well as Cu stabilizer with high Residual Resistance Ratio (RRR) to provide electromagnetic stabilization and protection. In powder-in-tube (PIT) wires the unreacted Nb7.5 wt%Ta outer layer of the tubular filaments acts as a diffusion barrier and protects the interfilamentary Cu stabilizer from Sn contamination. A high RRR requirement generally imposes a restricted A15 reaction heat treatment to prevent localized full reaction of the filament that could allow Sn to reach the Cu. In this study we investigate recent high quality PIT wires that achieve a J c (12 T, 4.2 K) up to ∼2500 A mm‑2 and find that the minimum diffusion barrier thickness decreases as the filament aspect ratio increases from ∼1 in the inner rings of filaments to 1.3 in the outer filament rings. We found that just 2–3 diffusion barrier breaches can degrade RRR from 300 to 150 or less. Using progressive etching of the Cu we also found that the RRR degradation is localized near the external filaments where deformation is highest. Consequently minimizing filament distortion during strand fabrication is important for reducing RRR degradation. The additional challenge of developing the highest possible J c must be addressed by forming the maximum fraction of high J c SG A15 and minimizing low J c large-grain (LG) A15 morphologies. In one wire we found that 15% of the filaments had a significantly enhanced SG/LG A15 ratio and no residual A15 in the core, a feature that opens a path to substantial J c improvement.

  5. Evaluation of critical current density and residual resistance ratio limits in powder in tube Nb3Sn conductors

    NASA Astrophysics Data System (ADS)

    Segal, Christopher; Tarantini, Chiara; Hawn Sung, Zu; Lee, Peter J.; Sailer, Bernd; Thoener, Manfred; Schlenga, Klaus; Ballarino, Amalia; Bottura, Luca; Bordini, Bernardo; Scheuerlein, Christian; Larbalestier, David C.

    2016-08-01

    High critical current density (J c) Nb3Sn A15 multifilamentary wires require a large volume fraction of small grain (SG), superconducting A15 phase, as well as Cu stabilizer with high Residual Resistance Ratio (RRR) to provide electromagnetic stabilization and protection. In powder-in-tube (PIT) wires the unreacted Nb7.5 wt%Ta outer layer of the tubular filaments acts as a diffusion barrier and protects the interfilamentary Cu stabilizer from Sn contamination. A high RRR requirement generally imposes a restricted A15 reaction heat treatment to prevent localized full reaction of the filament that could allow Sn to reach the Cu. In this study we investigate recent high quality PIT wires that achieve a J c (12 T, 4.2 K) up to ˜2500 A mm-2 and find that the minimum diffusion barrier thickness decreases as the filament aspect ratio increases from ˜1 in the inner rings of filaments to 1.3 in the outer filament rings. We found that just 2-3 diffusion barrier breaches can degrade RRR from 300 to 150 or less. Using progressive etching of the Cu we also found that the RRR degradation is localized near the external filaments where deformation is highest. Consequently minimizing filament distortion during strand fabrication is important for reducing RRR degradation. The additional challenge of developing the highest possible J c must be addressed by forming the maximum fraction of high J c SG A15 and minimizing low J c large-grain (LG) A15 morphologies. In one wire we found that 15% of the filaments had a significantly enhanced SG/LG A15 ratio and no residual A15 in the core, a feature that opens a path to substantial J c improvement.

  6. Evaluation of critical current density and residual resistance ratio limits in powder in tube Nb3Sn conductors

    DOE PAGES

    Segal, Christopher; Tarantini, Chiara; Sung, Zu Hawn; Lee, Peter J.; Sailer, Bernd; Thoener, Manfred; Schlenga, Klaus; Ballarino, Amalia; Bottura, Luca; Bordini, Bernardo; et al

    2016-06-10

    High critical current density (Jc) Nb3Sn A15 multifilamentary wires require a large volume fraction of small grain, superconducting A15 phase, as well as Cu stabilizer with high Residual Resistance Ratio (RRR) to provide electromagnetic stabilization and protection. In Powder-in-Tube (PIT) wires the unreacted Nb7.5wt.%Ta outer layer of the tubular filaments acts as a diffusion barrier and protects the interfilamentary Cu stabilizer from Sn contamination. A high RRR requirement generally imposes a restricted A15 reaction heat treatment (HT) to prevent localized full reaction of the filament that could allow Sn to reach the Cu. In this paper we investigate recent highmore » quality PIT wires that achieve a Jc(12 T, 4.2 K) up to ~2500 A/mm-2 and find that the minimum diffusion barrier thickness decreases as the filament aspect ratio increases from ~1 in the inner rings of filaments to 1.3 in the outer filament rings. We found that just 2-3 diffusion barrier breaches can degrade RRR from 300 to 150 or less. Using progressive etching of the Cu we also found that the RRR degradation is localized near the external filaments where deformation is highest. Consequently minimizing filament distortion during strand fabrication is important for reducing RRR degradation. The additional challenge of developing the highest possible Jc must be addressed by forming the maximum fraction of high Jc small-grain (SG) A15 and minimizing low Jc large-grain (LG) A15 morphologies. Finally, in one wire we found that 15% of the filaments had a significantly enhanced SG/LG A15 ratio and no residual A15 in the core, a feature that opens a path to substantial Jc improvement.« less

  7. Decreasing the Limits of Detection and Analysis Time of Ion Current Rectification Biosensing Measurements via a Mechanically Applied Pressure Differential.

    PubMed

    Schibel, Anna E P; Ervin, Eric N

    2015-07-01

    Improving on the analytical capabilities of a measurement is a fundamental challenge with all assays, particularly decreasing the limit of detection while maintaining a practical associated analysis time. Of late, ion current rectification (ICR) biosensing measurements have received a great deal of attention as an analyte-specific, label-free assay. In ICR biosensing, a nanopore coated with an analyte specific binding molecule (e.g., an antibody, an aptamer, etc.) is used to detect a target analyte based on the ability of the target analyte to alter the ICR response of the nanopore upon it binding to the aperture interior. This binding changes the local surface charge and/or size of the nanopore aperture, thus altering its ICR response in a time dependent manner. Here, we report the ability to enhance the transport of a target analyte molecule to and through the aperture of an antibody modified glass nanopore membrane (AMGNM) with the application of a mechanically applied pressure differential. We demonstrate that there is an optimal pressure that balances the flux of the target analyte through the AMGNM aperture with its ability to be bound and detected. Applying the optimal pressure differential allows for picomolar concentrations of the cleaved form of synaptosomal-associated protein 25 (cSNAP-25) to be detected within the same analysis time as micromolar concentrations detected without the use of the pressure differential. The methodology presented here significantly expands the utility of ICR biosensing measurements for detecting low-abundance biomolecules by lowering the limit of detection and reducing the associated analysis time. PMID:26043367

  8. Fifty Years of Technological Innovation: Potential and Limitations of Current Technologies in Abdominal Magnetic Resonance Imaging and Computed Tomography.

    PubMed

    Attenberger, Ulrike I; Morelli, John; Budjan, Johannes; Henzler, Thomas; Sourbron, Steven; Bock, Michael; Riffel, Philipp; Hernando, Diego; Ong, Melissa M; Schoenberg, Stefan O

    2015-09-01

    Magnetic resonance imaging (MRI) has become an important modality for the diagnosis of intra-abdominal pathology. Hardware and pulse sequence developments have made it possible to derive not only morphologic but also functional information related to organ perfusion (dynamic contrast-enhanced MRI), oxygen saturation (blood oxygen level dependent), tissue cellularity (diffusion-weighted imaging), and tissue composition (spectroscopy). These techniques enable a more specific assessment of pathologic lesions and organ functionality. Magnetic resonance imaging has thus transitioned from a purely morphologic examination to a modality from which image-based disease biomarkers can be derived. This fits well with several emerging trends in radiology, such as the need to accurately assess response to costly treatment strategies and the need to improve lesion characterization to potentially avoid biopsy. Meanwhile, the cost-effectiveness, availability, and robustness of computed tomography (CT) ensure its place as the current workhorse for clinical imaging. Although the lower soft tissue contrast of CT relative to MRI is a long-standing limitation, other disadvantages such as ionizing radiation exposure have become a matter of public concern. Nevertheless, recent technical developments such as dual-energy CT or dynamic volume perfusion CT also provide more functional imaging beyond morphology.The aim of this article was to review and discuss the most important recent technical developments in abdominal MRI and state-of-the-art CT, with an eye toward the future, providing examples of their clinical utility for the evaluation of hepatic and renal pathologies.

  9. Human health and the environment can't wait for reform: current opportunities for the federal government and states to address chemical risks under the Toxic Substances Control Act.

    PubMed

    Trevisan, Lauren

    2011-01-01

    Expressing its concern about growing rates of cancer and other diseases, coupled with the lack of data about the effect of the thousands of chemicals used in U.S. society, in 1976 Congress enacted the Toxic Substances Control Act (TSCA). Congress intended for TSCA to shed new light on chemical risks and provide the U.S. Environmental Protection Agency (EPA) with a set of tools to address those risks and protect human health and the environment. In the years since TSCA's passage, the procedural hurdles and the difficult-to-meet legal standards built into the statute, along with a court decision rejecting EPA's use of its authority to ban dangerous chemicals, have impeded EPA's ability to regulate chemical use and manufacture. This Comment argues that both the EPA and state governments have the authority to act now to address the risks posed by dangerous chemicals. By utilizing certain sections of the statute in new and aggressive ways, EPA can effectively address chemical risks. Further, this Comment argues that TSCA's preemption provision affords states leeway to continue to regulate the use of chemicals within their borders. Though reform of TSCA is necessary, EPA and states can effectively protect against chemical risks in the near-term by using the full extent of their authority under the current law.

  10. Experiments on current-driven three-dimensional ion sound turbulence. I - Return-current limited electron beam injection. II - Wave dynamics

    NASA Technical Reports Server (NTRS)

    Stenzel, R. L.

    1978-01-01

    Pulsed electron beam injection into a weakly collisional magnetized background plasma is investigated experimentally; properties of the electron beam and background plasma, as well as the low-frequency instabilities and wave dynamics, are discussed. The current of the injected beam closes via a field-aligned return current of background electrons. Through study of the frequency and wavenumber distribution, together with the electron distribution function, the low-frequency instabilities associated with the pulsed injection are identified as ion acoustic waves driven unstable by the return current. The frequency cut-off of the instabilities predicted from renormalized plasma turbulence theory, has been verified experimentally.

  11. Approach to Recover Hydrocarbons from Currently Off-Limit Areas of the Antrim Formation, MI Using Low-Impact Technologies

    SciTech Connect

    James Wood; William Quinlan

    2008-09-30

    The goal of this project was to develop and execute a novel drilling and completion program in the Antrim Shale near the western shoreline of Northern Michigan. The target was the gas in the Lower Antrim Formation (Upper Devonian). Another goal was to see if drilling permits could be obtained from the Michigan DNR that would allow exploitation of reserves currently off-limits to exploration. This project met both of these goals: the DNR (Michigan Department of Natural Resources) issued permits that allow drilling the shallow subsurface for exploration and production. This project obtained drilling permits for the original demonstration well AG-A-MING 4-12 HD (API: 21-009-58153-0000) and AG-A-MING 4-12 HD1 (API: 21-009-58153-0100) as well as for similar Antrim wells in Benzie County, MI, the Colfax 3-28 HD and nearby Colfax 2-28 HD which were substituted for the AG-A-MING well. This project also developed successful techniques and strategies for producing the shallow gas. In addition to the project demonstration well over 20 wells have been drilled to date into the shallow Antrim as a result of this project's findings. Further, fracture stimulation has proven to be a vital step in improving the deliverability of wells to deem them commercial. Our initial plan was very simple; the 'J-well' design. We proposed to drill a vertical or slant well 30.48 meters (100 feet) below the glacial drift, set required casing, then angle back up to tap the resource lying between the base to the drift and the conventional vertical well. The 'J'-well design was tested at Mancelona Township in Antrim County in February of 2007 with the St. Mancelona 2-12 HD 3.

  12. Current investigations into the genotoxicity of zinc oxide and silica nanoparticles in mammalian models in vitro and in vivo: carcinogenic/genotoxic potential, relevant mechanisms and biomarkers, artifacts, and limitations

    PubMed Central

    Kwon, Jee Young; Koedrith, Preeyaporn; Seo, Young Rok

    2014-01-01

    Engineered nanoparticles (NPs) are widely used in many sectors, such as food, medicine, military, and sport, but their unique characteristics may cause deleterious health effects. Close attention is being paid to metal NP genotoxicity; however, NP genotoxic/carcinogenic effects and the underlying mechanisms remain to be elucidated. In this review, we address some metal and metal oxide NPs of interest and current genotoxicity tests in vitro and in vivo. Metal NPs can cause DNA damage such as chromosomal aberrations, DNA strand breaks, oxidative DNA damage, and mutations. We also discuss several parameters that may affect genotoxic response, including physicochemical properties, widely used assays/end point tests, and experimental conditions. Although potential biomarkers of nanogenotoxicity or carcinogenicity are suggested, inconsistent findings in the literature render results inconclusive due to a variety of factors. Advantages and limitations related to different methods for investigating genotoxicity are described, and future directions and recommendations for better understanding genotoxic potential are addressed. PMID:25565845

  13. Detection of weak magnetic fields induced by electrical currents with MRI: theoretical and practical limits of sensitivity.

    PubMed

    Hatada, Tomohisa; Sekino, Masaki; Ueno, Shoogo

    2004-01-01

    Detection of weak magnetic fields induced by neuronal electrical activities with magnetic resonance imaging (MRI) is a potentially effective method for functional imaging of the brain. In this study, we compared the theoretical and practical limits of sensitivity for detecting weak magnetic fields with a columnar phantom. The theoretical limit of sensitivity was estimated from signal and noise intensities in magnetic resonance images. The theoretical limit of sensitivity was approximately 10(-8)T. The practical limit was 10 times the theoretical limit. The dependence of the theoretical limit of sensitivity on acquisition parameters, such as the repetition time (TR), echo time (TE), number of pixels, and spectral width, was quantitatively evaluated. The results indicated the existence of an optimal value in T(E)/T2*.

  14. ENSYSTROB - Design, manufacturing and test of a 3-phase resistive fault current limiter based on coated conductors for medium voltage application

    NASA Astrophysics Data System (ADS)

    Elschner, S.; Kudymow, A.; Brand, J.; Fink, S.; Goldacker, W.; Grilli, F.; Noe, M.; Vojenciak, M.; Hobl, A.; Bludau, M.; Jänke, C.; Krämer, S.; Bock, J.

    2012-11-01

    Within the German project ENSYSTROB a 3-phase resistive fault current limiter for medium voltage applications (12 kV, 533 Arms) was designed, built, tested and installed in the grid for a one year’s field test. The superconducting modules are made of YBCO coated conductors and replace the modules of an already successfully tested limiter on the basis of BSCCO 2212 bulk material. The components are multifilar spirals equipped with pairs of 12 mm wide YBCO tapes. The single components were characterized with respect to critical current, AC losses and limitation behavior under all possible operation conditions. The finally mounted limiter was successfully tested with respect to high voltage and limitation according to the standards of the customer. It is now installed and operating in its field test location. Finally we give a first comparison of both materials with respect to the different operational aspects.

  15. Addressing adolescent pregnancy with legislation.

    PubMed

    Montgomery, Tiffany M; Folken, Lori; Seitz, Melody A

    2014-01-01

    Adolescent pregnancy is a concern among many women's health practitioners. While it is practical and appropriate to work to prevent adolescent pregnancy by educating adolescents in health care clinics, schools and adolescent-friendly community-based organizations, suggesting and supporting legislative efforts to reduce adolescent pregnancy can help address the issue on an even larger scale. This article aims to help nurses better understand current legislation that addresses adolescent pregnancy, and to encourage support of future adolescent pregnancy prevention legislation. PMID:25145716

  16. Addressing adolescent pregnancy with legislation.

    PubMed

    Montgomery, Tiffany M; Folken, Lori; Seitz, Melody A

    2014-01-01

    Adolescent pregnancy is a concern among many women's health practitioners. While it is practical and appropriate to work to prevent adolescent pregnancy by educating adolescents in health care clinics, schools and adolescent-friendly community-based organizations, suggesting and supporting legislative efforts to reduce adolescent pregnancy can help address the issue on an even larger scale. This article aims to help nurses better understand current legislation that addresses adolescent pregnancy, and to encourage support of future adolescent pregnancy prevention legislation.

  17. An improved low-voltage ride-through performance of DFIG based wind plant using stator dynamic composite fault current limiter.

    PubMed

    Gayen, P K; Chatterjee, D; Goswami, S K

    2016-05-01

    In this paper, an enhanced low-voltage ride-through (LVRT) performance of a grid connected doubly fed induction generator (DFIG) has been presented with the usage of stator dynamic composite fault current limiter (SDCFCL). This protection circuit comprises of a suitable series resistor-inductor combination and parallel bidirectional semiconductor switch. The SDCFCL facilitates double benefits such as reduction of rotor induced open circuit voltage due to increased value of stator total inductance and concurrent increase of rotor impedance. Both effects will limit rotor circuit over current and over voltage situation more secured way in comparison to the conventional scheme like the dynamic rotor current limiter (RCL) during any type of fault situation. The proposed concept is validated through the simulation study of the grid integrated 2.0MW DFIG.

  18. An improved low-voltage ride-through performance of DFIG based wind plant using stator dynamic composite fault current limiter.

    PubMed

    Gayen, P K; Chatterjee, D; Goswami, S K

    2016-05-01

    In this paper, an enhanced low-voltage ride-through (LVRT) performance of a grid connected doubly fed induction generator (DFIG) has been presented with the usage of stator dynamic composite fault current limiter (SDCFCL). This protection circuit comprises of a suitable series resistor-inductor combination and parallel bidirectional semiconductor switch. The SDCFCL facilitates double benefits such as reduction of rotor induced open circuit voltage due to increased value of stator total inductance and concurrent increase of rotor impedance. Both effects will limit rotor circuit over current and over voltage situation more secured way in comparison to the conventional scheme like the dynamic rotor current limiter (RCL) during any type of fault situation. The proposed concept is validated through the simulation study of the grid integrated 2.0MW DFIG. PMID:26876377

  19. buffer Layer Growth, the Thickness Dependence of Jc in Coated Conductors, Local Identification of Current Limiting Mechanisms and Participation in the Wire Development Group

    SciTech Connect

    Larbalestier, David; Hellstron, Eric; Abraimov, Dmytro

    2011-12-17

    The primary thrusts of our work were to provide critical understanding of how best to enhance the current-carrying capacity of coated conductors. These include the deconstruction of Jc as a function of fim thickness, the growth of in situ films incorporating strong pinning centers and the use of a suite of position-sensitive tools that enable location and analysis of key areas where current-limiting occurs.

  20. Limitations and Potential in Current Research on Services for People with Mental Illness in the Criminal Justice System

    ERIC Educational Resources Information Center

    Draine, Jeffrey; Wilson, Amy Blank; Pogorzelski, Wendy

    2007-01-01

    Intervention at the intersection of the mental health and criminal justice systems has followed a small set of service models with limited success and a narrow impact on the quality of treatment available to people with mental illness who experience arrest, court processing, incarceration, and release. In reviewing research on police, court, and…

  1. Limiting the Temperatures in Naturally Ventilated Buildings in Warm Climates. Building Research Establishment Current Paper 7/74.

    ERIC Educational Resources Information Center

    Petherbridge, P.

    Formulas used in the calculation of cooling loads and indoor temperatures are employed to demonstrate the influence of various building parameters--such as thermal transmittance (U-value), solar absorptivity, and thermal storage--on the indoor thermal environment. The analysis leads to guidance on ways of limiting temperatures in naturally…

  2. Estimation of the potential efficiency of a multijunction solar cell at a limit balance of photogenerated currents

    SciTech Connect

    Mintairov, M. A. Evstropov, V. V.; Mintairov, S. A.; Shvarts, M. Z.; Timoshina, N. Kh.; Kalyuzhnyy, N. A.

    2015-05-15

    A method is proposed for estimating the potential efficiency which can be achieved in an initially unbalanced multijunction solar cell by the mutual convergence of photogenerated currents: to extract this current from a relatively narrow band-gap cell and to add it to a relatively wide-gap cell. It is already known that the properties facilitating relative convergence are inherent to such objects as bound excitons, quantum dots, donor-acceptor pairs, and others located in relatively wide-gap cells. In fact, the proposed method is reduced to the problem of obtaining such a required light current-voltage (I–V) characteristic which corresponds to the equality of all photogenerated short-circuit currents. Two methods for obtaining the required light I–V characteristic are used. The first one is selection of the spectral composition of the radiation incident on the multijunction solar cell from an illuminator. The second method is a double shift of the dark I–V characteristic: a current shift J{sub g} (common set photogenerated current) and a voltage shift (−J{sub g}R{sub s}), where R{sub s} is the series resistance. For the light and dark I–V characteristics, a general analytical expression is derived, which considers the effect of so-called luminescence coupling in multijunction solar cells. The experimental I–V characteristics are compared with the calculated ones for a three-junction InGaP/GaAs/Ge solar cell with R{sub s} = 0.019 Ω cm{sup 2} and a maximum factual efficiency of 36.9%. Its maximum potential efficiency is estimated as 41.2%.

  3. Observation of increased space-charge limited thermionic electron emission current by neutral gas ionization in a weakly-ionized deuterium plasma

    SciTech Connect

    Hollmann, E. M.; Yu, J. H.; Doerner, R. P.; Nishijima, D.; Seraydarian, R. P.

    2015-09-14

    The thermionic electron emission current emitted from a laser-produced hot spot on a tungsten target in weakly-ionized deuterium plasma is measured. It is found to be one to two orders of magnitude larger than expected for bipolar space charge limited thermionic emission current assuming an unperturbed background plasma. This difference is attributed to the plasma being modified by ionization of background neutrals by the emitted electrons. This result indicates that the allowable level of emitted thermionic electron current can be significantly enhanced in weakly-ionized plasmas due to the presence of large neutral densities.

  4. Why Don't You See What I Mean? Prospects and Limitations of Current Automatic Sign Recognition Research

    ERIC Educational Resources Information Center

    ten Holt, Gineke; Hendriks, Petra; Andriga, Tjeerd

    2006-01-01

    This article presents an overview of current automatic sign recognition research. A review of recent studies, as well as on our own research, has identified several problem areas that hamper successful sign recognition by a computer. Some of these problems are shared with automatic speech recognition, whereas others seem to be unique to automatic…

  5. Variable Speed Wind Power Generation System Using Direct Torque Control Suited for Maximum Power Control within Voltage and Current Limitations of Converter

    NASA Astrophysics Data System (ADS)

    Inoue, Yukinori; Morimoto, Shigeo; Sanada, Masayuki

    This paper proposes a variable speed wind generation system using a direct torque controlled interior permanent magnet synchronous generator. The proposed system has no wind speed and generator position sensors, and thus, it is considered that the proposed system has cost and reliability advantages. The proposed direct torque control (DTC) system in wind power generation has several advantages over conventional current control. First, DTC is well suited for the maximum power point tracking (MPPT) control that is implemented by controlling the generator torque. Second, the method of flux-weakening to maintain the terminal voltage at the limiting value of the converter is simple. Finally, a novel method is proposed for torque limiting, which makes it easy to maintain the armature current at the limiting value. The proposed method accomplishes current limiting using the reactive torque, which is calculated as the inner product of the flux and current. This does not require generator parameters such as magnet flux and inductances. Experimental results demonstrate the effectiveness of the proposed system using a wind turbine emulator instead of the actual wind turbine.

  6. Research on fast fault identification method of 10.5 kV/1.5 kA superconducting fault current limiter

    NASA Astrophysics Data System (ADS)

    Zhang, Zhifeng; Sun, Qiang; Xiao, Liye; Liu, Daqian; Qiu, Ming; Qiu, Qinquan; Zhang, Guomin; Dai, Shaotao; Lin, Liangzhen

    2014-09-01

    Superconducting fault current limiter (SFCL) is a prospective electric devices connected in series in power grid to limit short-circuit current. A 10.5 kV/1.5 kA 3-phase SFCL with HTS coil of 6.24 mH was developed at IEECAS in China in 2005, which was operated in a local power grid in Hunan province for more than 11,000 h, and integrated lately in a superconducting power substation in Baiyin city in 2011 and is still running safely and reliably. In order to reduce the fault response time and enhance the performance of the SFCL, we analyzed the structure characteristics of the SFCL and discussed the variation of currents and voltages of the HTS coil and the bridge during the fault time. The simulation and tests results of power system validate the feasibility of the fast fault identification method.

  7. LIMITATIONS OF EDDY CURRENT RESIDUAL STRESS PROFILING IN SURFACE-TREATED ENGINE ALLOYS OF VARIOUS HARDNESS LEVELS

    SciTech Connect

    Abu-Nabah, B. A.; Hassan, W. T.; Blodgett, M. P.; Nagy, P. B.

    2010-02-22

    Recent research results indicated that eddy current conductivity measurements might be exploited for nondestructive evaluation of subsurface residual stresses in surface-treated nickel-base superalloy components. This paper presents new results that indicate that in some popular nickel-base superalloys the relationship between the electric conductivity profile and the sought residual stress profile is more tenuous than previously thought. It is shown that in IN718 the relationship is very sensitive to the state of precipitation hardening and, if left uncorrected, could render the eddy current technique unsuitable for residual stress profiling in components of 36 HRC or harder, i.e., in most critical engine applications. The presented experimental results show that the observed dramatic change in the eddy current response of hardened IN718 to surface treatment is caused by very fine nanometer-scale features of the microstructure, such as gamma' and gamma'' precipitates, rather than micrometer-scale features, such as changing grain size or carbide precipitates.

  8. Electromotive force and current in a superconducting solenoid with limited length induced by a bar magnet and a monopole

    NASA Astrophysics Data System (ADS)

    Ma, Lianxi

    The magnetic flux ΦB, electromotive force, EMF, and current Iin, induced by a moving magnetic bar and an imaginary magnetic monopole in a superconducting solenoid of multiple turns and length L, are numerically calculated. The magnetic field of the bar magnet is approximated with the magnetic field along z axis of a solenoid with length l and radius a and current I, while the magnetic field of the monopole is supposed to be inversely proportional to r2. Calculations show that, for a bar magnet, ΦB and Iin essentially saturate when the bar moves inside superconducting solenoid, so EMF is zero while Iin is constant. EMF is only induced when the bar enters and exits the solenoid and Iin is zero after the bar leaves the solenoid. For a magnetic monopole, ΦB is discontinuous (from positive maximum to negative maximum) when the it moves through each turn of the superconducting solenoid, but EMF caused by dΦB /dt is continuous while the EMF induced by the a moving monopole is a delta function (moving monopole produces a ring-shaped E field). The total EMFTot in solenoid is the superposition of EMF of each turn of coil and the plateau appears. The current Iin continues to grow while the monopole leaves the solenoid. Thanks to Dr. Liancun Zheng and Mr. Lin Liu for verifying my calculation.

  9. Assaying embryotoxicity in the test tube: current limitations of the embryonic stem cell test (EST) challenging its applicability domain.

    PubMed

    Riebeling, Christian; Hayess, Katrin; Peters, Annelieke K; Steemans, Margino; Spielmann, Horst; Luch, Andreas; Seiler, Andrea E M

    2012-05-01

    Testing for embryotoxicity in vitro is an attractive alternative to animal experimentation. The embryonic stem cell test (EST) is such a method, and it has been formally validated by the European Centre for the Validation of Alternative Methods. A number of recent studies have underscored the potential of this method. However, the EST performed well below the 78% accuracy expected from the validation study using a new set of chemicals and pharmaceutical compounds, and also of toxicity criteria, tested to enlarge the database of the validated EST as part of the Work Package III of the ReProTect Project funded within the 6th Framework Programme of the European Union. To assess the performance and applicability domain of the EST we present a detailed review of the substances and their effects in the EST being nitrofen, ochratoxin A, D-penicillamine, methylazoxymethanol, lovastatin, papaverine, warfarin, β-aminopropionitrile, dinoseb, furosemide, doxylamine, pravastatin, and metoclopramide. By delineation of the molecular mechanisms of the substances we identify six categories of reasons for misclassifications. Some of these limitations might also affect other in vitro methods assessing embryotoxicity. Substances that fall into these categories need to be included in future validation sets and in validation guidelines for embryotoxicity testing. Most importantly, we suggest conceivable improvements and additions to the EST which will resolve most of the limitations.

  10. Voltage clamp limitations of dual whole-cell gap junction current and voltage recordings. I. Conductance measurements.

    PubMed

    Veenstra, R D

    2001-05-01

    Previous correction methods for series access resistance errors in the dual whole-cell configuration did not take into account the effect of nonzero resting potentials (E(rest)) and junctional reversal potentials (E(rev)). Dual whole-cell currents were modeled according to resistor-circuit analysis and two correction formulas for the measurement of junctional currents (I(j)) were assessed. The equations for I(j), derived from Kirchoff's law before and after baseline subtraction of the nonjunctional current, were assessed for accuracy under a variety of whole-cell patch-clamp recording conditions. Both equations accurately correct for dual whole-cell voltage-clamp errors provided that the cellular parameters are included in the nonbaseline subtracted I(j) derivations. Junctional conductance (g(j)) estimates are most reliable at high junctional resistance (R(j)) values and minimize the need for corrective methods based on electrode series and cellular input resistances (R(el) and R(in)). In the "open-cell" configuration, low R(j) values relative to R(in) are required for accurate g(j) estimates. These methods provide the basis for accurate quantitative measurements of junctional resistance (or conductance) of gap junction channels or connexin hemichannels in the dual whole-cell or open-cell configurations. Revaluation of V(j)-dependent gating of rat connexin40 g(j) produced nearly identical Boltzmann fits to previously published data. Continuous g(j)-V(j) curves generated by variable slope V(j) ramps provide for more accurate fits and assessment of the time-dependence of the half-inactivation voltage and net gating charge movement. PMID:11325726

  11. The contribution of TWIK-1 channels to astrocyte K+ current is limited by retention in intracellular compartments

    PubMed Central

    Wang, Wei; Putra, Adhytia; Schools, Gary P.; Ma, Baofeng; Chen, Haijun; Kaczmarek, Leonard K.; Barhanin, Jacques; Lesage, Florian; Zhou, Min

    2013-01-01

    TWIK-1 two-pore domain K+ channels are expressed abundantly in astrocytes. In the present study, we examined the extent to which TWIK-1 contributes to the linear current-voltage (I–V) relationship (passive) K+ membrane conductance, a dominant electrophysiological feature of mature hippocampal astrocytes. Astrocytes from TWIK-1 knockout mice have a more negative resting potential than those from wild type animals and a reduction in both inward rectification and Cs+ permeability. Nevertheless, the overall whole-cell passive conductance is not altered significantly in TWIK-1 knockout astrocytes. The expression of Kir4.1 and TREK-1, two other major astrocytic K+ channels, or of other two-pore K+ channels is not altered in TWIK-1 knockout mice, suggesting that the mild effect of TWIK-1 knockout does not result from compensation by these channels. Fractionation experiments showed that TWIK-1 is primarily localized in intracellular cytoplasmic fractions (55%) and mildly hydrophobic internal compartment fractions (41%), with only 5% in fractions containing plasma membranes. Our study revealed that TWIK-1 proteins are mainly located in the intracellular compartments of hippocampal astrocyte under physiological condition, therefore a minimal contribution of TWIK-1 channels to whole-cell currents is likely attributable to a relatively low level presence of channels in the plasma membrane. PMID:24368895

  12. Barrier inhomogeneities limited current and 1/f noise transport in GaN based nanoscale Schottky barrier diodes

    NASA Astrophysics Data System (ADS)

    Kumar, Ashutosh; Heilmann, M.; Latzel, Michael; Kapoor, Raman; Sharma, Intu; Göbelt, M.; Christiansen, Silke H.; Kumar, Vikram; Singh, Rajendra

    2016-06-01

    The electrical behaviour of Schottky barrier diodes realized on vertically standing individual GaN nanorods and array of nanorods is investigated. The Schottky diodes on individual nanorod show highest barrier height in comparison with large area diodes on nanorods array and epitaxial film which is in contrast with previously published work. The discrepancy between the electrical behaviour of nanoscale Schottky diodes and large area diodes is explained using cathodoluminescence measurements, surface potential analysis using Kelvin probe force microscopy and 1ow frequency noise measurements. The noise measurements on large area diodes on nanorods array and epitaxial film suggest the presence of barrier inhomogeneities at the metal/semiconductor interface which deviate the noise spectra from Lorentzian to 1/f type. These barrier inhomogeneities in large area diodes resulted in reduced barrier height whereas due to the limited role of barrier inhomogeneities in individual nanorod based Schottky diode, a higher barrier height is obtained.

  13. Barrier inhomogeneities limited current and 1/f noise transport in GaN based nanoscale Schottky barrier diodes.

    PubMed

    Kumar, Ashutosh; Heilmann, M; Latzel, Michael; Kapoor, Raman; Sharma, Intu; Göbelt, M; Christiansen, Silke H; Kumar, Vikram; Singh, Rajendra

    2016-01-01

    The electrical behaviour of Schottky barrier diodes realized on vertically standing individual GaN nanorods and array of nanorods is investigated. The Schottky diodes on individual nanorod show highest barrier height in comparison with large area diodes on nanorods array and epitaxial film which is in contrast with previously published work. The discrepancy between the electrical behaviour of nanoscale Schottky diodes and large area diodes is explained using cathodoluminescence measurements, surface potential analysis using Kelvin probe force microscopy and 1ow frequency noise measurements. The noise measurements on large area diodes on nanorods array and epitaxial film suggest the presence of barrier inhomogeneities at the metal/semiconductor interface which deviate the noise spectra from Lorentzian to 1/f type. These barrier inhomogeneities in large area diodes resulted in reduced barrier height whereas due to the limited role of barrier inhomogeneities in individual nanorod based Schottky diode, a higher barrier height is obtained.

  14. Barrier inhomogeneities limited current and 1/f noise transport in GaN based nanoscale Schottky barrier diodes

    PubMed Central

    Kumar, Ashutosh; Heilmann, M.; Latzel, Michael; Kapoor, Raman; Sharma, Intu; Göbelt, M.; Christiansen, Silke H.; Kumar, Vikram; Singh, Rajendra

    2016-01-01

    The electrical behaviour of Schottky barrier diodes realized on vertically standing individual GaN nanorods and array of nanorods is investigated. The Schottky diodes on individual nanorod show highest barrier height in comparison with large area diodes on nanorods array and epitaxial film which is in contrast with previously published work. The discrepancy between the electrical behaviour of nanoscale Schottky diodes and large area diodes is explained using cathodoluminescence measurements, surface potential analysis using Kelvin probe force microscopy and 1ow frequency noise measurements. The noise measurements on large area diodes on nanorods array and epitaxial film suggest the presence of barrier inhomogeneities at the metal/semiconductor interface which deviate the noise spectra from Lorentzian to 1/f type. These barrier inhomogeneities in large area diodes resulted in reduced barrier height whereas due to the limited role of barrier inhomogeneities in individual nanorod based Schottky diode, a higher barrier height is obtained. PMID:27282258

  15. [Evaluation of scientific production in different subareas of Public Health: limits of the current model and contributions to the debate].

    PubMed

    Iriart, Jorge Alberto Bernstein; Deslandes, Suely Ferreira; Martin, Denise; Camargo Jr, Kenneth Rochel de; Carvalho, Marilia Sá; Coeli, Cláudia Medina

    2015-10-01

    The aim of this study was to discuss the limits of the quantitative evaluation model for scientific production in Public Health. An analysis of the scientific production of professors from the various subareas of Public Health was performed for 2010-2012. Distributions of the mean annual score for professors were compared according to subareas. The study estimated the likelihood that 60% of the professors in the graduate studies programs scored P50 (Very Good) or higher in their area. Professors of Epidemiology showed a significantly higher median annual score. Graduate studies programs whose faculty included at least 60% of Epidemiology professors and fewer than 10% from the subarea Social and Human Sciences in Health were significantly more likely to achieve a "Very Good" classification. The observed inequalities in scientific production between different subareas of Public Health point to the need to rethink their evaluation in order to avoid reproducing iniquities that have harmful consequences for the field's diversity.

  16. Non-invasive brain stimulation for the treatment of brain diseases in childhood and adolescence: state of the art, current limits and future challenges

    PubMed Central

    Vicario, Carmelo M.; Nitsche, Michael A.

    2013-01-01

    In the last decades interest in application of non-invasive brain stimulation for enhancing neural functions is growing continuously. However, the use of such techniques in pediatric populations remains rather limited and mainly confined to the treatment of severe neurological and psychiatric diseases. In this article we provide a complete review of non-invasive brain stimulation studies conducted in pediatric populations. We also provide a brief discussion about the current limitations and future directions in a field of research still very young and full of issues to be explored. PMID:24324410

  17. RyRCa2+ Leak Limits Cardiac Ca2+ Window Current Overcoming the Tonic Effect of Calmodulin in Mice

    PubMed Central

    Fernández-Velasco, María; Neco, Patricia; Mercado-Morales, Martha; Delgado, Carmen; Napolitano, Carlo; Priori, Silvia G.; Richard, Sylvain; María Gómez, Ana; Benitah, Jean-Pierre

    2011-01-01

    Ca2+ mediates the functional coupling between L-type Ca2+ channel (LTCC) and sarcoplasmic reticulum (SR) Ca2+ release channel (ryanodine receptor, RyR), participating in key pathophysiological processes. This crosstalk manifests as the orthograde Ca2+-induced Ca2+-release (CICR) mechanism triggered by Ca2+ influx, but also as the retrograde Ca2+-dependent inactivation (CDI) of LTCC, which depends on both Ca2+ permeating through the LTCC itself and on SR Ca2+ release through the RyR. This latter effect has been suggested to rely on local rather than global Ca2+ signaling, which might parallel the nanodomain control of CDI carried out through calmodulin (CaM). Analyzing the CICR in catecholaminergic polymorphic ventricular tachycardia (CPVT) mice as a model of RyR-generated Ca2+ leak, we evidence here that increased occurrence of the discrete local SR Ca2+ releases through the RyRs (Ca2+ sparks) causea depolarizing shift in activation and a hyperpolarizing shift inisochronic inactivation of cardiac LTCC current resulting in the reduction of window current. Both increasing fast [Ca2+]i buffer capacity or depleting SR Ca2+ store blunted these changes, which could be reproduced in WT cells by RyRCa2+ leak induced with Ryanodol and CaM inhibition.Our results unveiled a new paradigm for CaM-dependent effect on LTCC gating and further the nanodomain Ca2+ control of LTCC, emphasizing the importance of spatio-temporal relationships between Ca2+ signals and CaM function. PMID:21673970

  18. Global Epidemiology of HIV Among Women and Girls Who Use or Inject Drugs: Current Knowledge and Limitations of Existing Data

    PubMed Central

    Larney, Sarah; Mathers, Bradley M.; Poteat, Tonia; Kamarulzaman, Adeeba; Degenhardt, Louisa

    2016-01-01

    Background Women and girls who use and inject drugs are a critical population at risk of HIV. In this article, we review data on the epidemiology of drug use and injection among women globally and HIV prevalence among women and girls who use and inject drugs. Results Women and girls comprise one-third of people who use and inject drugs globally. There is substantial variation in HIV prevalence in this population, between and within countries. There is a pronounced lack of data examining HIV risk among particularly vulnerable subpopulations of women who use and inject drugs, including women who have sex with women, transgender women, racial and ethnic minority women, and young women. Women who use and inject drugs experience stigma and discrimination that affect access to services, and high levels of sexual risk exposures. Conclusions There are significant gaps in our understanding of the epidemiology of drug use and injecting among women and girls and HIV risk and prevalence in this population. Women are frequently underrepresented in studies of drug use and HIV risk and prevalence among people who inject drugs, limiting our understanding of possible sex differences in this population. Most research originates from developed countries and may not be generalizable to other settings. A great deal of work is needed to improve understanding of HIV among particularly vulnerable subpopulations, such as transgender women who use drugs. Better data are critical to efforts to advocate for the needs of women and girls who use and inject drugs. PMID:25978476

  19. Ocean-Atmosphere Heat Exchange: Limitations of Currently Available Datasets and Potential for Future Progress (Solicited Talk)

    NASA Astrophysics Data System (ADS)

    Josey, Simon

    2016-04-01

    The flux of heat between the ocean and the atmosphere is a key element of the global climate system, central to variations in the ocean heat budget and variations in surface temperature. Factors determining the heat exchange will be discussed using models and observations with an emphasis on the period 1990-2015. This period include changes associated with the potential warming hiatus and more recently the major El Nino event that developed in 2015. The ability of leading datasets to reliably estimate surface flux changes is limited by a number of factors and these will be discussed in the context of variations in other components of the climate system. Progress towards obtaining more reliable climatological estimates of the heat exchange will also be considered with reference to recent developments using residual techniques and ocean reanalyses in addition to atmospheric reanalysis, remote sensing and ship based datasets. In addition, use of surface meteorological fields to generate ocean model forcing will be examined together with recent developments using high resolution coupled ocean-atmosphere models. Finally, the potential for significant advances in regions of major uncertainty using the growing network of surface flux buoys will be discussed with a focus on two moorings now in place in the Southern Ocean.

  20. The State of the Art of the Zebrafish Model for Toxicology and Toxicologic Pathology Research—Advantages and Current Limitations

    PubMed Central

    Spitsbergen, Jan M.; Kent, Michael L.

    2007-01-01

    The zebrafish (Danio rerio) is now the pre-eminent vertebrate model system for clarification of the roles of specific genes and signaling pathways in development. The zebrafish genome will be completely sequenced within the next 1–2 years. Together with the substantial historical database regarding basic developmental biology, toxicology, and gene transfer, the rich foundation of molecular genetic and genomic data makes zebrafish a powerful model system for clarifying mechanisms in toxicity. In contrast to the highly advanced knowledge base on molecular developmental genetics in zebrafish, our database regarding infectious and noninfectious diseases and pathologic lesions in zebrafish lags far behind the information available on most other domestic mammalian and avian species, particularly rodents. Currently, minimal data are available regarding spontaneous neoplasm rates or spontaneous aging lesions in any of the commonly used wild-type or mutant lines of zebrafish. Therefore, to fully utilize the potential of zebrafish as an animal model for understanding human development, disease, and toxicology we must greatly advance our knowledge on zebrafish diseases and pathology. PMID:12597434

  1. Effect of inductors to mitigate the hot-spot problem in parallel-connected superconducting thin-film fault current limiting elements

    NASA Astrophysics Data System (ADS)

    Yamasaki, H.; Furuse, M.; Kaiho, K.

    2015-06-01

    We have been developing superconducting thin-film fault current limiter (FCL) elements, in which high-resistivity Au-Ag alloy shunt layers are used to protect YBa2Cu3O7 (YBCO) thin films deposited on CeO2-buffered sapphire substrates. The high resistance of the thin films enables the element to withstand high electric fields of more than 40 Vpeak cm-1 during the current-limiting period after quenching, thus greatly reducing the amount of YBCO thin film needed and, consequently, the cost of an FCL. We have succeeded in fabricating and testing 500 V/200 A FCL modules using two 20 cm long YBCO films connected in parallel. In the present study, we performed extensive switching experiments on FCL elements, in which two YBCO films are connected in parallel to achieve higher rated currents, and confirmed the previously observed phenomenon that the hot-spot problem causing film damage just after quench initiation becomes more severe when the total critical current of the thin films is higher. We have investigated the origin of this phenomenon and found that a rapid current transfer from the first-quenched film with lower critical current to the other film causes higher current in the secondly-quenched film that sometimes leads to hot spots. It is demonstrated that the serious hot-spot problem can be mitigated by the use of inductors when the high-resistance FCL elements are connected in parallel. Based on these findings we propose an appropriate architecture of a high electric-field superconducting thin-film FCL that can be used in a real power grid.

  2. Innovative Legal Approaches to Address Obesity

    PubMed Central

    Pomeranz, Jennifer L; Teret, Stephen P; Sugarman, Stephen D; Rutkow, Lainie; Brownell, Kelly D

    2009-01-01

    Context: The law is a powerful public health tool with considerable potential to address the obesity issue. Scientific advances, gaps in the current regulatory environment, and new ways of conceptualizing rights and responsibilities offer a foundation for legal innovation. Methods: This article connects developments in public health and nutrition with legal advances to define promising avenues for preventing obesity through the application of the law. Findings: Two sets of approaches are defined: (1) direct application of the law to factors known to contribute to obesity and (2) original and innovative legal solutions that address the weak regulatory stance of government and the ineffectiveness of existing policies used to control obesity. Specific legal strategies are discussed for limiting children's food marketing, confronting the potential addictive properties of food, compelling industry speech, increasing government speech, regulating conduct, using tort litigation, applying nuisance law as a litigation strategy, and considering performance-based regulation as an alternative to typical regulatory actions. Finally, preemption is an overriding issue and can play both a facilitative and a hindering role in obesity policy. Conclusions: Legal solutions are immediately available to the government to address obesity and should be considered at the federal, state, and local levels. New and innovative legal solutions represent opportunities to take the law in creative directions and to link legal, nutrition, and public health communities in constructive ways. PMID:19298420

  3. Construction and characterization of an inductive superconducting current limiting device based on ceramic Y 1Ba 2Cu 3O 7 - δ O-rings

    NASA Astrophysics Data System (ADS)

    Currás, S. R.; Santos, R.; Domarco, G.; Díaz, A.; Veira, J. A.; Maza, J.; François, M. X.; Vidal, F.

    Experimental results about the response of a small-scale superconducting inductive device as current limiter are reported. The device is based on ring-shaped samples of bulk Y 1Ba 2Cu 3O 7 - δ coupled to a primary coil through a magnetic core. The samples were obtained by pressing into an O-ring shape Y 1Ba 2Cu 3O 7 - δ powders, which reacted following the standard ceramic process. The size of the O-rings was 1 cm internal diameter, 1.6 cm external diameter, and 0.3 cm height. The response of the device was measured at liquid nitrogen temperature as a function of the type of magnetic core, the critical current of each individual superconducting O-ring, the number of O-rings used simultaneously, the frequency of the a.c. current and the number of turns of the primary coil.

  4. High-power-density fault-current limiting devices using superconducting YBa2Cu3O7 films and high-resistivity alloy shunt layers

    NASA Astrophysics Data System (ADS)

    Yamasaki, Hirofumi; Furuse, Mitsuho; Nakagawa, Yoshihiko

    2004-11-01

    Switching of superconducting thin-film resistive fault-current limiting devices with alloy shunt layers was studied. Au -Ag alloy thin films, whose room-temperature resistivity is about six times higher than that of pure gold, were sputter deposited on YBa2Cu3O7 films on sapphire substrates with high critical current density of Jc=3.05±0.05MA /cm2. A small sample, 5mm wide and 40mm long, had the capacity of a rated current of 32Arms in normal operation and withstood a high voltage of 107Vrms for 0.1s after switching, resulting in a very high switching power density of ˜1.7kVA /cm2, which is more than four times higher than conventional devices using gold shunt layers.

  5. Battery Cell Voltage Sensing and Balancing Using Addressable Transformers

    NASA Technical Reports Server (NTRS)

    Davies, Francis

    2009-01-01

    A document discusses the use of saturating transformers in a matrix arrangement to address individual cells in a high voltage battery. This arrangement is able to monitor and charge individual cells while limiting the complexity of circuitry in the battery. The arrangement has inherent galvanic isolation, low cell leakage currents, and allows a single bad cell in a battery of several hundred cells to be easily spotted.

  6. Addressivity in cogenerative dialogues

    NASA Astrophysics Data System (ADS)

    Hsu, Pei-Ling

    2014-03-01

    Ashraf Shady's paper provides a first-hand reflection on how a foreign teacher used cogens as culturally adaptive pedagogy to address cultural misalignments with students. In this paper, Shady drew on several cogen sessions to showcase his journey of using different forms of cogens with his students. To improve the quality of cogens, one strategy he used was to adjust the number of participants in cogens. As a result, some cogens worked and others did not. During the course of reading his paper, I was impressed by his creative and flexible use of cogens and at the same time was intrigued by the question of why some cogens work and not others. In searching for an answer, I found that Mikhail Bakhtin's dialogism, especially the concept of addressivity, provides a comprehensive framework to address this question. In this commentary, I reanalyze the cogen episodes described in Shady's paper in the light of dialogism. My analysis suggests that addressivity plays an important role in mediating the success of cogens. Cogens with high addressivity function as internally persuasive discourse that allows diverse consciousnesses to coexist and so likely affords productive dialogues. The implications of addressivity in teaching and learning are further discussed.

  7. Addressing psychiatric comorbidity.

    PubMed

    Woody, G E; McLellan, A T; O'Brien, C P; Luborsky, L

    1991-01-01

    Research studies indicate that addressing psychiatric comorbidity can improve treatment for selected groups of substance-abusing patients. However, the chances for implementing the necessary techniques on a large scale are compromised by the absence of professional input and guidance within programs. This is especially true in public programs, which treat some of the most disadvantaged, disturbed, and socially destructive individuals in the entire mental health system. One starting point for upgrading the level of knowledge and training of staff members who work in this large treatment system could be to develop a better and more authoritative information dissemination network. Such a system exists in medicine; physicians are expected to read appropriate journals and to guide their treatment decisions using the data contained in the journals. Standards of practice and methods for modifying current practice are within the tradition of reading new facts, studying old ones, and comparing treatment outcome under different conditions with what is actually being done. No such general system of information-gathering or -sharing exists, particularly in public treatment programs. One of the most flagrant examples of this "educational shortfall" can be found among those methadone programs that adamantly insist on prescribing no more than 30 to 35 mg/day for all patients, in spite of the overwhelming evidence that these dose levels generally are inadequate. In some cases, program directors are unaware of studies that have shown the relationship between dose and outcome. In other cases, they are aware of the studies but do not modify their practices accordingly. This example of inadequate dosing is offered as an example of one situation that could be improved by adherence to a system of authoritative and systematic information dissemination. Many issues in substance abuse treatment do not lend themselves to information dissemination as readily as that of methadone dosing

  8. Current flow and pair creation at low altitude in rotation-powered pulsars' force-free magnetospheres: space charge limited flow

    NASA Astrophysics Data System (ADS)

    Timokhin, A. N.; Arons, J.

    2013-02-01

    We report the results of an investigation of particle acceleration and electron-positron plasma generation at low altitude in the polar magnetic flux tubes of rotation-powered pulsars, when the stellar surface is free to emit whatever charges and currents are demanded by the force-free magnetosphere. We apply a new 1D hybrid plasma simulation code to the dynamical problem, using Particle-in-Cell methods for the dynamics of the charged particles, including a determination of the collective electrostatic fluctuations in the plasma, combined with a Monte Carlo treatment of the high-energy gamma-rays that mediate the formation of the electron-positron pairs. We assume the electric current flowing through the pair creation zone is fixed by the much higher inductance magnetosphere, and adopt the results of force-free magnetosphere models to provide the currents which must be carried by the accelerator. The models are spatially one dimensional, and designed to explore the physics, although of practical relevance to young, high-voltage pulsars. We observe novel behaviour (a) When the current density j is less than the Goldreich-Julian value (0 < j/jGJ < 1), space charge limited acceleration of the current carrying beam is mild, with the full Goldreich-Julian charge density comprising the charge densities of the beam and a cloud of electrically trapped particles with the same sign of charge as the beam. The voltage drops are of the order of mc2/e, and pair creation is absent. (b) When the current density exceeds the Goldreich-Julian value (j/jGJ > 1), the system develops high voltage drops (TV or greater), causing emission of curvature gamma-rays and intense bursts of pair creation. The bursts exhibit limit cycle behaviour, with characteristic time-scales somewhat longer than the relativistic fly-by time over distances comparable to the polar cap diameter (microseconds). (c) In return current regions, where j/jGJ < 0, the system develops similar bursts of pair creation

  9. A Limiting Current Oxygen Sensor Based on LSGM as a Solid Electrolyte and LSGMN ( N = Fe, Co) as a Dense Diffusion Barrier

    NASA Astrophysics Data System (ADS)

    Liu, Tao; Gao, Xiang; He, Bei-Gang; Yu, Jing-Kun

    2016-07-01

    The La0.8Sr0.2(Ga1- x Co x )0.8Mg0.2O3- δ (LSGMC x = 0.05, 0.1, 0.15, 0.2, 0.25) and La0.8Sr0.2(Ga1- x Fe x )0.8Mg0.2O3- δ (LSGMF x = 0.1, 0.2, 0.3) samples were prepared by solid-state reaction. The structure, conductivity, thermal expansion behavior, and chemical compatibility were studied by XRD, dilatometry, and four-terminal method. A limiting current oxygen sensor was prepared with La0.8Sr0.2Ga0.83Mg0.17O2.815 as a solid electrolyte and La0.8Sr0.2(Ga0.75Co0.25)0.8Mg0.2O3- δ as a dense diffusion barrier. The oxygen-sensitive characteristic was measured at different oxygen concentrations. The results show that the phase structure of samples is cubic, except La0.8Sr0.2(Ga0.75Co0.25)0.8Mg0.2O3- δ , which has a hexagonal structure. The change in activation energy for electrical conductivity and the increase in thermal expansion coefficient are confirmed to correlate with an increasing concentration of oxygen vacancies. The limiting current oxygen sensor exhibits a good limiting current platform and the limiting current depends linearly on the oxygen concentration: I L(mA) = 12.8519 + 2.2667 x_{{{O}_{{2}} }} (mol%, 0 < x_{{{{O}}_{ 2} }} < 3.31) at 750 °C, I L(mA) = 14.3222 + 3.5180 x_{{{O}_{{2}} }} (mol%, 0 < x_{{{{O}}_{ 2} }} < 4.16) at 800 °C, and I L(mA) = 15.2872 + 5.0269x_{{{O}_{{2}} }}(mol%, 0 < x_{{{{O}}_{ 2} }} < 4.12) at 850 °C. The sensor has the best sensitivity at 850 °C. As the oxygen concentration increases, the interface resistance of the sensor decreases at 850 °C.

  10. Effect of interdot Coulomb repulsion on tunneling current through a double quantum dot system in the weak tunneling limit: Strong electron-phonon coupling

    NASA Astrophysics Data System (ADS)

    Medvedev, Igor G.

    2009-07-01

    Pronounced effects of the interdot Coulomb repulsion on the tunnel current/gate voltage dependence at the ambient conditions are predicted for the double quantum dot system in the serial configuration immersed in the electrolyte solution in the case of the weak tunneling of electrons both between the dots and between the dots and leads. Electrons at the dots are coupled strongly to the classical phonon modes and Debye screening of the electric field is taken into account. The infinite intradot Coulomb repulsion limit is used. The effects consist of (i) a very large width of the maximum of the tunnel current/gate voltage dependence [of the order of -kBTln(k0/k) , where k0 and k are the characteristic rates of the electron tunneling between the dots and between the dots and leads, respectively] in the limit k0/k→0 , (ii) the dependence of the positions of the maxima of the current/gate voltage curve and their widths on the sign of the difference of the electron energy levels δ of the quantum dots and the energy of the polaron shift, and (iii) narrow-width Coulomb blockade peaks in the tunnel current/gate voltage curve for k0≥k . The dependence of the differential conductance on the gate voltage, the energy of the interdot Coulomb repulsion, the Debye screening length, and values of k0/k and δ are studied. It is shown that the curves of the differential conductance/bias voltage dependence can be very different for different values of these parameters. These parameters also determine the position of the regions of the negative differential conductance which exist in the general case.

  11. Addressing Social Issues.

    ERIC Educational Resources Information Center

    Schoebel, Susan

    1991-01-01

    Maintains that advertising can help people become more aware of social responsibilities. Describes a successful nationwide newspaper advertising competition for college students in which ads address social issues such as literacy, drugs, teen suicide, and teen pregnancy. Notes how the ads have helped grassroots programs throughout the United…

  12. Addressing Sexual Harassment

    ERIC Educational Resources Information Center

    Young, Ellie L.; Ashbaker, Betty Y.

    2008-01-01

    This article discusses ways on how to address the problem of sexual harassment in schools. Sexual harassment--simply defined as any unwanted and unwelcome sexual behavior--is a sensitive topic. Merely providing students, parents, and staff members with information about the school's sexual harassment policy is insufficient; schools must take…

  13. Current Flow and Pair Creation at Low Altitude in Rotation-Powered Pulsars' Force-Free Magnetospheres: Space Charge Limited Flow

    NASA Technical Reports Server (NTRS)

    Timokhin, A. N.; Arons, J.

    2013-01-01

    We report the results of an investigation of particle acceleration and electron-positron plasma generation at low altitude in the polar magnetic flux tubes of rotation-powered pulsars, when the stellar surface is free to emit whatever charges and currents are demanded by the force-free magnetosphere. We apply a new 1D hybrid plasma simulation code to the dynamical problem, using Particle-in-Cell methods for the dynamics of the charged particles, including a determination of the collective electrostatic fluctuations in the plasma, combined with a Monte Carlo treatment of the high-energy gamma-rays that mediate the formation of the electron-positron pairs.We assume the electric current flowing through the pair creation zone is fixed by the much higher inductance magnetosphere, and adopt the results of force-free magnetosphere models to provide the currents which must be carried by the accelerator. The models are spatially one dimensional, and designed to explore the physics, although of practical relevance to young, high-voltage pulsars. We observe novel behaviour (a) When the current density j is less than the Goldreich-Julian value (0 < j/j(sub GJ) < 1), space charge limited acceleration of the current carrying beam is mild, with the full Goldreich-Julian charge density comprising the charge densities of the beam and a cloud of electrically trapped particles with the same sign of charge as the beam. The voltage drops are of the order of mc(sup 2)/e, and pair creation is absent. (b) When the current density exceeds the Goldreich-Julian value (j/j(sub GJ) > 1), the system develops high voltage drops (TV or greater), causing emission of curvature gamma-rays and intense bursts of pair creation. The bursts exhibit limit cycle behaviour, with characteristic time-scales somewhat longer than the relativistic fly-by time over distances comparable to the polar cap diameter (microseconds). (c) In return current regions, where j/j(sub GJ) < 0, the system develops similar

  14. Holographic content addressable storage

    NASA Astrophysics Data System (ADS)

    Chao, Tien-Hsin; Lu, Thomas; Reyes, George

    2015-03-01

    We have developed a Holographic Content Addressable Storage (HCAS) architecture. The HCAS systems consists of a DMD (Digital Micromirror Array) as the input Spatial Light Modulator (SLM), a CMOS (Complementary Metal-oxide Semiconductor) sensor as the output photodetector and a photorefractive crystal as the recording media. The HCAS system is capable of performing optical correlation of an input image/feature against massive reference data set stored in the holographic memory. Detailed system analysis will be reported in this paper.

  15. Addressing inequities in healthy eating.

    PubMed

    Friel, Sharon; Hattersley, Libby; Ford, Laura; O'Rourke, Kerryn

    2015-09-01

    What, when, where and how much people eat is influenced by a complex mix of factors at societal, community and individual levels. These influences operate both directly through the food system and indirectly through political, economic, social and cultural pathways that cause social stratification and influence the quality of conditions in which people live their lives. These factors are the social determinants of inequities in healthy eating. This paper provides an overview of the current evidence base for addressing these determinants and for the promotion of equity in healthy eating. PMID:26420812

  16. Addressing the workforce pipeline challenge

    SciTech Connect

    Leonard Bond; Kevin Kostelnik; Richard Holman

    2006-11-01

    A secure and affordable energy supply is essential for achieving U.S. national security, in continuing U.S. prosperity and in laying the foundations to enable future economic growth. To meet this goal the next generation energy workforce in the U.S., in particular those needed to support instrumentation, controls and advanced operations and maintenance, is a critical element. The workforce is aging and a new workforce pipeline, to support both current generation and new build has yet to be established. The paper reviews the challenges and some actions being taken to address this need.

  17. Bioreactors Addressing Diabetes Mellitus

    PubMed Central

    Minteer, Danielle M.; Gerlach, Jorg C.

    2014-01-01

    The concept of bioreactors in biochemical engineering is a well-established process; however, the idea of applying bioreactor technology to biomedical and tissue engineering issues is relatively novel and has been rapidly accepted as a culture model. Tissue engineers have developed and adapted various types of bioreactors in which to culture many different cell types and therapies addressing several diseases, including diabetes mellitus types 1 and 2. With a rising world of bioreactor development and an ever increasing diagnosis rate of diabetes, this review aims to highlight bioreactor history and emerging bioreactor technologies used for diabetes-related cell culture and therapies. PMID:25160666

  18. Bioreactors addressing diabetes mellitus.

    PubMed

    Minteer, Danielle M; Gerlach, Jorg C; Marra, Kacey G

    2014-11-01

    The concept of bioreactors in biochemical engineering is a well-established process; however, the idea of applying bioreactor technology to biomedical and tissue engineering issues is relatively novel and has been rapidly accepted as a culture model. Tissue engineers have developed and adapted various types of bioreactors in which to culture many different cell types and therapies addressing several diseases, including diabetes mellitus types 1 and 2. With a rising world of bioreactor development and an ever increasing diagnosis rate of diabetes, this review aims to highlight bioreactor history and emerging bioreactor technologies used for diabetes-related cell culture and therapies.

  19. Content addressable memory project

    NASA Technical Reports Server (NTRS)

    Hall, J. Storrs; Levy, Saul; Smith, Donald E.; Miyake, Keith M.

    1992-01-01

    A parameterized version of the tree processor was designed and tested (by simulation). The leaf processor design is 90 percent complete. We expect to complete and test a combination of tree and leaf cell designs in the next period. Work is proceeding on algorithms for the computer aided manufacturing (CAM), and once the design is complete we will begin simulating algorithms for large problems. The following topics are covered: (1) the practical implementation of content addressable memory; (2) design of a LEAF cell for the Rutgers CAM architecture; (3) a circuit design tool user's manual; and (4) design and analysis of efficient hierarchical interconnection networks.

  20. Thermal stress imposed by prototype bilayer and current ground crew chemical defense ensembles: a limited laboratory comparison. Final report, 30 June 1986-1 January 1987

    SciTech Connect

    Krock, L.P.; Navalta, R.; Myhre, L.G.

    1988-07-01

    An open bilayer ground-crew chemical defense ensemble (CDE) was proposed to reduce the thermal burden during vapor-only exposure periods. This study compared the thermal-stress profile of the proposed ensemble to that produced by the currently employed closed CDE. Four subjects, alternating ensembles on separate days, walked on a treadmill in an environmental chamber at 5.3 km/h (3.3 mph) and 2% grade (an energy expenditure of 350 kcal/h) for alternating work/rest to achieve significant recovery. Mean total sweat production was lower (1.38 vs. 2.50 liters) and percent sweat evaporation greater (65.7% vs. 30.0%) in the prototype ensemble than in the CDE. The prototype ensemble provided greater heat dissipation and allowed more-efficient sweat evaporation which had the double benefit of reducing heat storage and limiting dehydration.

  1. Addressing Environmental Health Inequalities

    PubMed Central

    Gouveia, Nelson

    2016-01-01

    Environmental health inequalities refer to health hazards disproportionately or unfairly distributed among the most vulnerable social groups, which are generally the most discriminated, poor populations and minorities affected by environmental risks. Although it has been known for a long time that health and disease are socially determined, only recently has this idea been incorporated into the conceptual and practical framework for the formulation of policies and strategies regarding health. In this Special Issue of the International Journal of Environmental Research and Public Health (IJERPH), “Addressing Environmental Health Inequalities—Proceedings from the ISEE Conference 2015”, we incorporate nine papers that were presented at the 27th Conference of the International Society for Environmental Epidemiology (ISEE), held in Sao Paulo, Brazil, in 2015. This small collection of articles provides a brief overview of the different aspects of this topic. Addressing environmental health inequalities is important for the transformation of our reality and for changing the actual development model towards more just, democratic, and sustainable societies driven by another form of relationship between nature, economy, science, and politics. PMID:27618906

  2. Addressing Environmental Health Inequalities.

    PubMed

    Gouveia, Nelson

    2016-01-01

    Environmental health inequalities refer to health hazards disproportionately or unfairly distributed among the most vulnerable social groups, which are generally the most discriminated, poor populations and minorities affected by environmental risks. Although it has been known for a long time that health and disease are socially determined, only recently has this idea been incorporated into the conceptual and practical framework for the formulation of policies and strategies regarding health. In this Special Issue of the International Journal of Environmental Research and Public Health (IJERPH), "Addressing Environmental Health Inequalities-Proceedings from the ISEE Conference 2015", we incorporate nine papers that were presented at the 27th Conference of the International Society for Environmental Epidemiology (ISEE), held in Sao Paulo, Brazil, in 2015. This small collection of articles provides a brief overview of the different aspects of this topic. Addressing environmental health inequalities is important for the transformation of our reality and for changing the actual development model towards more just, democratic, and sustainable societies driven by another form of relationship between nature, economy, science, and politics. PMID:27618906

  3. Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current

    PubMed Central

    Assmy, Philipp; Smetacek, Victor; Montresor, Marina; Klaas, Christine; Henjes, Joachim; Strass, Volker H.; Arrieta, Jesús M.; Bathmann, Ulrich; Berg, Gry M.; Breitbarth, Eike; Cisewski, Boris; Friedrichs, Lars; Fuchs, Nike; Herndl, Gerhard J.; Jansen, Sandra; Krägefsky, Sören; Latasa, Mikel; Peeken, Ilka; Röttgers, Rüdiger; Scharek, Renate; Schüller, Susanne E.; Steigenberger, Sebastian; Webb, Adrian; Wolf-Gladrow, Dieter

    2013-01-01

    Diatoms of the iron-replete continental margins and North Atlantic are key exporters of organic carbon. In contrast, diatoms of the iron-limited Antarctic Circumpolar Current sequester silicon, but comparatively little carbon, in the underlying deep ocean and sediments. Because the Southern Ocean is the major hub of oceanic nutrient distribution, selective silicon sequestration there limits diatom blooms elsewhere and consequently the biotic carbon sequestration potential of the entire ocean. We investigated this paradox in an in situ iron fertilization experiment by comparing accumulation and sinking of diatom populations inside and outside the iron-fertilized patch over 5 wk. A bloom comprising various thin- and thick-shelled diatom species developed inside the patch despite the presence of large grazer populations. After the third week, most of the thinner-shelled diatom species underwent mass mortality, formed large, mucous aggregates, and sank out en masse (carbon sinkers). In contrast, thicker-shelled species, in particular Fragilariopsis kerguelensis, persisted in the surface layers, sank mainly empty shells continuously, and reduced silicate concentrations to similar levels both inside and outside the patch (silica sinkers). These patterns imply that thick-shelled, hence grazer-protected, diatom species evolved in response to heavy copepod grazing pressure in the presence of an abundant silicate supply. The ecology of these silica-sinking species decouples silicon and carbon cycles in the iron-limited Southern Ocean, whereas carbon-sinking species, when stimulated by iron fertilization, export more carbon per silicon. Our results suggest that large-scale iron fertilization of the silicate-rich Southern Ocean will not change silicon sequestration but will add carbon to the sinking silica flux. PMID:24248337

  4. Assessment of Current Process Modeling Approaches to Determine Their Limitations, Applicability and Developments Needed for Long-Fiber Thermoplastic Injection Molded Composites

    SciTech Connect

    Nguyen, Ba Nghiep; Holbery, Jim; Smith, Mark T.; Kunc, Vlastimil; Norris, Robert E.; Phelps, Jay; Tucker III, Charles L.

    2006-11-30

    This report describes the status of the current process modeling approaches to predict the behavior and flow of fiber-filled thermoplastics under injection molding conditions. Previously, models have been developed to simulate the injection molding of short-fiber thermoplastics, and an as-formed composite part or component can then be predicted that contains a microstructure resulting from the constituents’ material properties and characteristics as well as the processing parameters. Our objective is to assess these models in order to determine their capabilities and limitations, and the developments needed for long-fiber injection-molded thermoplastics (LFTs). First, the concentration regimes are summarized to facilitate the understanding of different types of fiber-fiber interaction that can occur for a given fiber volume fraction. After the formulation of the fiber suspension flow problem and the simplification leading to the Hele-Shaw approach, the interaction mechanisms are discussed. Next, the establishment of the rheological constitutive equation is presented that reflects the coupled flow/orientation nature. The decoupled flow/orientation approach is also discussed which constitutes a good simplification for many applications involving flows in thin cavities. Finally, before outlining the necessary developments for LFTs, some applications of the current orientation model and the so-called modified Folgar-Tucker model are illustrated through the fiber orientation predictions for selected LFT samples.

  5. Content addressable memory project

    NASA Technical Reports Server (NTRS)

    Hall, Josh; Levy, Saul; Smith, D.; Wei, S.; Miyake, K.; Murdocca, M.

    1991-01-01

    The progress on the Rutgers CAM (Content Addressable Memory) Project is described. The overall design of the system is completed at the architectural level and described. The machine is composed of two kinds of cells: (1) the CAM cells which include both memory and processor, and support local processing within each cell; and (2) the tree cells, which have smaller instruction set, and provide global processing over the CAM cells. A parameterized design of the basic CAM cell is completed. Progress was made on the final specification of the CPS. The machine architecture was driven by the design of algorithms whose requirements are reflected in the resulted instruction set(s). A few of these algorithms are described.

  6. Bax: Addressed to kill.

    PubMed

    Renault, Thibaud T; Manon, Stéphen

    2011-09-01

    The pro-apoptototic protein Bax (Bcl-2 Associated protein X) plays a central role in the mitochondria-dependent apoptotic pathway. In healthy mammalian cells, Bax is essentially cytosolic and inactive. Following a death signal, the protein is translocated to the outer mitochondrial membrane, where it promotes a permeabilization that favors the release of different apoptogenic factors, such as cytochrome c. The regulation of Bax translocation is associated to conformational changes that are under the control of different factors. The evidences showing the involvement of different Bax domains in its mitochondrial localization are presented. The interactions between Bax and its different partners are described in relation to their ability to promote (or prevent) Bax conformational changes leading to mitochondrial addressing and to the acquisition of the capacity to permeabilize the outer mitochondrial membrane. PMID:21641962

  7. [Keynote address: Climate change

    SciTech Connect

    Forrister, D.

    1994-12-31

    Broadly speaking, the climate issue is moving from talk to action both in the United States and internationally. While few nations have adopted strict controls or stiff new taxes, a number of them are developing action plans that are making clear their intention to ramp up activity between now and the year 2000... and beyond. There are sensible, economically efficient strategies to be undertaken in the near term that offer the possibility, in many countries, to avoid more draconian measures. These strategies are by-and-large the same measures that the National Academy of Sciences recommended in a 1991 report called, Policy Implications of Greenhouse Warming. The author thinks the Academy`s most important policy contribution was how it recommended the nations act in the face of uncertain science and high risks--that cost effective measures are adopted as cheap insurance... just as nations insure against other high risk, low certainty possibilities, like catastrophic health insurance, auto insurance, and fire insurance. This insurance theme is still right. First, the author addresses how the international climate change negotiations are beginning to produce insurance measures. Next, the author will discuss some of the key issues to watch in those negotiations that relate to longer-term insurance. And finally, the author will report on progress in the United States on the climate insurance plan--The President`s Climate Action Plan.

  8. Addressing Passive Smoking in Children

    PubMed Central

    Hutchinson, Sasha G.; Kuijlaars, Jennifer S.; Mesters, Ilse; Muris, Jean W. M.; van Schayck, Constant P.; Dompeling, Edward; Feron, Frans J. M.

    2014-01-01

    Background A significant number of parents are unaware or unconvinced of the health consequences of passive smoking (PS) in children. Physicians could increase parental awareness by giving personal advice. Aim To evaluate the current practices of three Dutch health professions (paediatricians, youth health care physicians, and family physicians) regarding parental counselling for passive smoking (PS) in children. Methods All physicians (n = 720) representing the three health professions in Limburg, the Netherlands, received an invitation to complete a self-administered electronic questionnaire including questions on their: sex, work experience, personal smoking habits, counselling practices and education regarding PS in children. Results The response rate was 34%. One tenth (11%) of the responding physicians always addressed PS in children, 32% often, 54% occasionally and 4% reported to never attend to it. The three health professions appeared comparable regarding their frequency of parental counselling for PS in children. Addressing PS was more likely when children had respiratory problems. Lack of time was the most frequently mentioned barrier, being very and somewhat applicable for respectively 14% and 43% of the physicians. One fourth of the responders had received postgraduate education about PS. Additionally, 49% of the responders who did not have any education about PS were interested in receiving it. Conclusions Physicians working in the paediatric field in Limburg, the Netherlands, could more frequently address PS in children with parents. Lack of time appeared to be the most mentioned barrier and physicians were more likely to counsel parents for PS in children with respiratory complaints/diseases. Finally, a need for more education on parental counselling for PS was expressed. PMID:24809443

  9. Lack of blood formate accumulation in humans following exposure to methanol vapor at the current permissible exposure limit of 200 ppm

    SciTech Connect

    Lee, E.W.; Terzo, T.S.; D'Arcy, J.B.; Gross, K.B.; Schreck, R.M. )

    1992-02-01

    Accumulation of formate, the putative toxic metabolite of methanol, in the blood and the relationship between pulmonary intake and blood methanol concentration were investigated in six human volunteers following a 6-hr exposure to 200 ppm methanol (the current Occupational Safety and Health Administration 8-hr time-weighted average permissible exposure limit). At the end of a 6-hr exposure to 200 ppm methanol at rest, the blood methanol concentration was increased from a mean of 1.8 micrograms/mL to 7.0 micrograms/mL. Under light exercise, the total amount of methanol inhaled during the 6-hr exposure period was 1.8 times that inhaled at rest. However, no statistically significant increase in blood methanol concentration was observed under exercise: the concentrations averaged 8.1 micrograms/mL. Formate did not accumulate in the blood above its background level following the 6-hr exposures to 200 ppm methanol whether subjects were exposed at rest or during exercise. Unlike the data collected from epidemiologic studies, the authors' results were obtained under well-controlled methanol exposure conditions and by using appropriate dietary restrictions. The data show that (1) the biological load of methanol would be the same regardless of whether workers are engaged in light physical activity when they are exposed to methanol vapors below 200 ppm and (2) the formate that is associated with acute methanol toxicities in humans does not accumulate in blood when methanol exposure concentrations are below 200 ppm.

  10. Multiple dating approach (14C, U/Th and 36Cl) of tsunami-transported reef-top megaclasts on Bonaire (Leeward Antilles) - potential and current limitations

    NASA Astrophysics Data System (ADS)

    Rixhon, Gilles; May, Simon Matthias; Engel, Max; Mechernich, Silke; Keulertz, Rebecca; Schroeder-Ritzrau, Andrea; Fohlmeister, Jens; Frank, Norbert; Dunai, Tibor; Brueckner, Helmut

    2016-04-01

    Coastal hazard assessment depends on reliable information on the magnitude and frequency of past high-energy wave events (EWE: tsunamis, storms). For this purpose onshore sedimentary records represent promising geo-archives for the mid- and late-Holocene EWE history. In comparison to fine-grained sediments which have been extensively studied in the recent past, supralittoral megaclasts are less investigated, essentially due to the difficulties related to the dating of corresponding depositional events, and thus their limited value for inferring the timing of major events. On Bonaire (Leeward Antilles, Caribbean), supratidal coarse-clast deposits form prominent landforms all around the island. Fields of large boulders (up to 150 t) are among the best-studied reef-top megaclasts worldwide. Transport by Holocene tsunamis is assumed at least for the largest boulders (Engel and May, 2012). Although a large dataset of 14C and electron spin resonance (ESR) ages is available for major coral rubble ridges and ramparts, showing some age clusters during the Late Holocene, it is still debated whether these data reflect the timing of major depositional/transport event(s), and how these data sets are biased by reworking of coral fragments. In addition, different processes may be responsible for the deposition of the coral rubble ridges and ramparts (storm) and the solitary megaclasts (tsunami). As an attempt to overcome the current challenges for dating the dislocation of the megaclasts, three distinct dating methods were implemented: (i) 14C dating of boring bivalves (Lithophaga) attached to the boulders; (ii) uranium-series (U/Th) dating of post-depositional, secondary calcitic flowstone at the underside of the boulders; and (iii) surface exposure dating of overturned boulders via 36Cl concentration measurements in corals. The three 14C datings yield age estimates >37 ka, i.e. most probably beyond the applicability of the method, which sheds doubt on the usefulness of this

  11. A novel electron gun with an independently addressable cathode array

    SciTech Connect

    Rudys, Joseph Matthew; Reed, Kim Warren; Pena, Gary Edward; Schneider, Larry X.

    2006-08-01

    The design of a novel electron gun with an array of independently addressable cathode elements is presented. Issues relating to operation in a 6.5 Tesla axial magnetic field are discussed. Simulations with the TriComp electromagnetic field code that were used to determine the space charge limited tube characteristic and to model focusing of the electron beam in the magnetic field are reviewed. Foil heating and stress calculations are discussed. The results of CYLTRAN simulations yielding the energy spectrum of the electron beam and the current transmitted through the foil window are presented.

  12. ANSI Standard: Complying with Background Noise Limits.

    ERIC Educational Resources Information Center

    Schaffer, Mark E.

    2003-01-01

    Discusses the new classroom acoustics standard, ANSI Standard S12.60, which specifies maximum sound level limits that are significantly lower than currently typical for classrooms. Addresses guidelines for unducted HVAC systems, ducted single-zone systems, and central VAV or multizone systems. (EV)

  13. From an 'ice-see' perspective: The current use, potential and limitations of Structure-from-Motion photogrammetry for cryospheric applications

    NASA Astrophysics Data System (ADS)

    Westoby, Matthew; Dunning, Stuart; Allan, Mark; Smith, Mark; Quincey, Duncan; Carrivick, Jonathan; Watson, C. Scott

    2016-04-01

    Structure-from-Motion with Multi-View Stereo (SfM-MVS) methods are rapidly becoming the tool of choice for geoscientists who require a relatively low-cost and viable alternative to traditional surveying technologies for characterising the form and short-term evolution of Earth surface landforms and landscapes. Uptake of SfM-MVS methods by workers in the cryospheric science community has been particularly rapid. The choice to use SfM-MVS has many logistical benefits which promote its adoption in remote glacial environments, namely the requirement for little more than a digital camera and proprietary or open-source software for topographic reconstruction, and a surveyed network of ground control to transform the resultant 3D models into a real-world co-ordinate system, if desired. Optionally, a dedicated aerial photography platform (e.g. kite, blimp, multirotor or fixed-wing UAV) may be used for initial photograph acquisition, which can facilitate glacier-scale observation and analysis. To date, cryospheric applications of SfM-MVS have included: the monitoring of glacier, moraine, and rock glacier movement; the evolution of ice cliffs on debris-covered glaciers; the reconstruction of ice-marginal or deglaciated topography; patch- and moraine-scale sedimentological characterisation; and the characterisation of glacier surfaces to monitor supraglacial drainage development or to inform energy balance modelling. This contribution will showcase existing applications and original data and discuss exciting potential opportunities and current limitations of the SfM-MVS method for the cryospheric sciences.

  14. Improved limits and portability over currently employed cadmium monitoring systems through preconcentration for detection by way of micro-/nanofluidic mechanisms

    NASA Astrophysics Data System (ADS)

    Wach, Paul

    Due to risk of environmental and biological accumulation of Cadmium (Cd), improved methods of early detection and monitoring must be explored as a preventative measure. Listed as one of the top three toxic heavy metals by the Environmental Protection Agency (EPA), the effects on ecological and human systems have well documented side-effects of physical mutation, reproductive sterility, kidney failure, liver disease, bone loss, and death. Found in batteries, metal plating, pigments, plastics, and cigarettes, Cd is also used as a neutron absorber in the nuclear industry as well as having 3 known radioactive isotopes. Urine Cd levels, which have been widely used to predict whole body levels, increase when kidney damage occurs, thus increasing the importance to monitor and detect as early as possible. Although several methods of detection and monitoring are currently in use, they are insufficient for reasons including massive expense, weak specificity causing false readings, and/or a lack of portability. By exploiting naturally occurring mechanisms known to micro-/nanofluidics, a novel approach to Cd detection, measurement, and preconcentration was explored using the finite element computational software COMSOL. An open flow system of a nanochannel was explored through manipulation of the surface charge density. With a dominant negatively charged density on the walls, positive surface charge densities were adjacently placed at the center of the nanochannel causing a constriction of flow and allowing preconcentration of the analytes. When the open flow system was scaled up to a microchannel, the mechanism was found to have little effect on constriction of the flow. A preconcentration effect was discovered in a closed flow system when the adjacent patches were modeled as being impermeable to charge, causing the molecules to migrate to and remain at the central region of the microchannel once the dynamic process reached steady state. It was found to have the ability to

  15. Addressing neurological disorders with neuromodulation.

    PubMed

    Oluigbo, Chima O; Rezai, Ali R

    2011-07-01

    Neurological disorders are becoming increasingly common in developed countries as a result of the aging population. In spite of medications, these disorders can result in progressive loss of function as well as chronic physical, cognitive, and emotional disability that ultimately places enormous emotional and economic on the patient, caretakers, and the society in general. Neuromodulation is emerging as a therapeutic option in these patients. Neuromodulation is a field, which involves implantable devices that allow for the reversible adjustable application of electrical, chemical, or biological agents to the central or peripheral nervous system with the objective of altering its functioning with the objective of achieving a therapeutic or clinically beneficial effect. It is a rapidly evolving field that brings together many different specialties in the fields of medicine, materials science, computer science and technology, biomedical, and neural engineering as well as the surgical or interventional specialties. It has multiple current and emerging indications, and an enormous potential for growth. The main challenges before it are in the need for effective collaboration between engineers, basic scientists, and clinicians to develop innovations that address specific problems resulting in new devices and clinical applications. PMID:21193369

  16. Addressing neurological disorders with neuromodulation.

    PubMed

    Oluigbo, Chima O; Rezai, Ali R

    2011-07-01

    Neurological disorders are becoming increasingly common in developed countries as a result of the aging population. In spite of medications, these disorders can result in progressive loss of function as well as chronic physical, cognitive, and emotional disability that ultimately places enormous emotional and economic on the patient, caretakers, and the society in general. Neuromodulation is emerging as a therapeutic option in these patients. Neuromodulation is a field, which involves implantable devices that allow for the reversible adjustable application of electrical, chemical, or biological agents to the central or peripheral nervous system with the objective of altering its functioning with the objective of achieving a therapeutic or clinically beneficial effect. It is a rapidly evolving field that brings together many different specialties in the fields of medicine, materials science, computer science and technology, biomedical, and neural engineering as well as the surgical or interventional specialties. It has multiple current and emerging indications, and an enormous potential for growth. The main challenges before it are in the need for effective collaboration between engineers, basic scientists, and clinicians to develop innovations that address specific problems resulting in new devices and clinical applications.

  17. Bilingual Cognitive Development: Addressing Three Gaps in Current Research.

    ERIC Educational Resources Information Center

    Diaz, Rafael M.

    1985-01-01

    Results question the validity of Cummins's threshold hypothesis and suggest that degree of bilingualism is related to variability in cognitive measures only before a certain threshold of proficiency in the second language is attained. A cause-effect model in which degree of bilingualism appears as the causal factor affecting children's cognitive…

  18. Swimming Against the Current: Zebrafish Help Address Educational Challenges.

    PubMed

    Pickart, Michael A; Liang, Jennifer; Hutson, Lara; Pierret, Christopher

    2016-08-01

    Zebrafish can be important tools for learning and authentic student research. The broad zebrafish community is rich with examples to improve education for learners of all ages and geographical locales. This special collection of articles is presented with the hope of encouraging readers to reflect on the educational outcomes reported here and to consider new ways zebrafish may engage others to learn and grow.

  19. Sun Protection: Current Management Strategies Addressing UV Exposure.

    PubMed

    Cohen, Leslie E; Grant, Robert T

    2016-07-01

    The use of sunscreen is essential for protection against photoaging and skin cancer. There is no global consensus on rating systems for sunscreens but it is essential to understand what makes a product broad-spectrum. In addition, physicians should have a general understanding that high-quality successful sunscreens should not only provide broad-spectrum ultraviolet A/B protection but should also be formulated so that they are easy to apply, are water resistant, and are photostable in order to increase user compliance.

  20. Current Research and Opportunities to Address Environmental Asbestos Exposures

    PubMed Central

    Larson, Theodore C.; Pfau, Jean C.; Gavett, Stephen H.; Shukla, Arti; Miller, Aubrey; Hines, Ronald

    2015-01-01

    Summary Asbestos-related diseases continue to result in approximately 120,000 deaths every year in the United States and worldwide. Although extensive research has been conducted on health effects of occupational exposures to asbestos, many issues related to environmental asbestos exposures remain unresolved. For example, environmental asbestos exposures associated with a former mine in Libby, Montana, have resulted in high rates of nonoccupational asbestos-related disease. Additionally, other areas with naturally occurring asbestos deposits near communities in the United States and overseas are undergoing investigations to assess exposures and potential health risks. Some of the latest public health, epidemiological, and basic research findings were presented at a workshop on asbestos at the 2014 annual meeting of the Society of Toxicology in Phoenix, Arizona. The following focus areas were discussed: a) mechanisms resulting in fibrosis and/or tumor development; b) relative toxicity of different forms of asbestos and other hazardous elongated mineral particles (EMPs); c) proper dose metrics (e.g., mass, fiber number, or surface area of fibers) when interpreting asbestos toxicity; d) asbestos exposure to susceptible populations; and e) using toxicological findings for risk assessment and remediation efforts. The workshop also featured asbestos research supported by the National Institute of Environmental Health Sciences, the Agency for Toxic Substances and Disease Registry, and the U.S. Environmental Protection Agency. Better protection of individuals from asbestos-related health effects will require stimulation of new multidisciplinary research to further our understanding of what constitutes hazardous exposures and risk factors associated with toxicity of asbestos and other hazardous EMPs (e.g., nanomaterials). PMID:26230287

  1. Current Research and Opportunities to Address Environmental Asbestos Exposures

    EPA Science Inventory

    Asbestos-related diseases continue to result in approximately 120,000 deaths every year in the United States and worldwide.Although extensive research has been conducted on health effects of occupational exposures to asbestos, many issues related to environmental asbestos exposur...

  2. Current Research and Opportunities to Address Environmental Asbestos Exposures.

    PubMed

    Carlin, Danielle J; Larson, Theodore C; Pfau, Jean C; Gavett, Stephen H; Shukla, Arti; Miller, Aubrey; Hines, Ronald

    2015-08-01

    Asbestos-related diseases continue to result in approximately 120,000 deaths every year in the United States and worldwide. Although extensive research has been conducted on health effects of occupational exposures to asbestos, many issues related to environmental asbestos exposures remain unresolved. For example, environmental asbestos exposures associated with a former mine in Libby, Montana, have resulted in high rates of nonoccupational asbestos-related disease. Additionally, other areas with naturally occurring asbestos deposits near communities in the United States and overseas are undergoing investigations to assess exposures and potential health risks. Some of the latest public health, epidemiological, and basic research findings were presented at a workshop on asbestos at the 2014 annual meeting of the Society of Toxicology in Phoenix, Arizona. The following focus areas were discussed: a) mechanisms resulting in fibrosis and/or tumor development; b) relative toxicity of different forms of asbestos and other hazardous elongated mineral particles (EMPs); c) proper dose metrics (e.g., mass, fiber number, or surface area of fibers) when interpreting asbestos toxicity; d) asbestos exposure to susceptible populations; and e) using toxicological findings for risk assessment and remediation efforts. The workshop also featured asbestos research supported by the National Institute of Environmental Health Sciences, the Agency for Toxic Substances and Disease Registry, and the U.S. Environmental Protection Agency. Better protection of individuals from asbestos-related health effects will require stimulation of new multidisciplinary research to further our understanding of what constitutes hazardous exposures and risk factors associated with toxicity of asbestos and other hazardous EMPs (e.g., nanomaterials).

  3. Interventions to address maternal and childhood undernutrition: current evidence.

    PubMed

    Bhutta, Zulfiqar A; Das, Jai K

    2014-01-01

    The global burden of undernutrition remains high with little evidence of change in many countries. We reviewed the evidence of the potential nutritional interventions and estimated their effect on nutrition-related outcomes of women and children. Among the maternal interventions, daily iron supplementation results in a 69% reduction in incidence of anemia, 20% in incidence of low birthweight (LBW) and improves mean birthweight. MMN supplementation during pregnancy has been shown to significantly decrease the number of LBW infants by 14% and small for gestational age (SGA) by 13%. Balanced protein-energy supplementation reduces the incidence of SGA by 32% and risk of stillbirths by 38%. Antimalarials when given to pregnant women increase the mean birthweight significantly and were associated with a 43% reduction in LBW and severe antenatal anemia by 38%. Among the neonatal and child interventions, educational/counseling interventions increased exclusive breastfeeding by 43% at 4-6 weeks and 137% at 6 months. Vitamin A supplementation (VAS) reduces all-cause mortality by 24% and results in a 14% reduction in the risk of infant mortality at 6 months. Intermittent iron supplementation in children reduces the risk of anemia by 49% and iron deficiency by 76%, and significantly improves hemoglobin and ferritin concentration. Preventive zinc supplementation in populations at risk of zinc deficiency decreases morbidity from childhood diarrhea and acute lower respiratory infections, and increases linear growth and weight gain among infants and young children. Among the supportive interventions, hand washing with soap significantly reduces diarrhea morbidity by 48%, though it depends on access to water. The effect of water treatment on diarrhea morbidity also appears similarly large with a 17% reduction. Recent research has established linkages of preconception interventions with improved maternal, perinatal and neonatal health outcomes, and it has been suggested that several proven interventions recommended during pregnancy may be even more effective if implemented before conception. These proven interventions, if scaled up have the potential to reduce the global burden of undernutrition substantially. PMID:24504207

  4. Sun Protection: Current Management Strategies Addressing UV Exposure.

    PubMed

    Cohen, Leslie E; Grant, Robert T

    2016-07-01

    The use of sunscreen is essential for protection against photoaging and skin cancer. There is no global consensus on rating systems for sunscreens but it is essential to understand what makes a product broad-spectrum. In addition, physicians should have a general understanding that high-quality successful sunscreens should not only provide broad-spectrum ultraviolet A/B protection but should also be formulated so that they are easy to apply, are water resistant, and are photostable in order to increase user compliance. PMID:27363775

  5. Interventions to address maternal and childhood undernutrition: current evidence.

    PubMed

    Bhutta, Zulfiqar A; Das, Jai K

    2014-01-01

    The global burden of undernutrition remains high with little evidence of change in many countries. We reviewed the evidence of the potential nutritional interventions and estimated their effect on nutrition-related outcomes of women and children. Among the maternal interventions, daily iron supplementation results in a 69% reduction in incidence of anemia, 20% in incidence of low birthweight (LBW) and improves mean birthweight. MMN supplementation during pregnancy has been shown to significantly decrease the number of LBW infants by 14% and small for gestational age (SGA) by 13%. Balanced protein-energy supplementation reduces the incidence of SGA by 32% and risk of stillbirths by 38%. Antimalarials when given to pregnant women increase the mean birthweight significantly and were associated with a 43% reduction in LBW and severe antenatal anemia by 38%. Among the neonatal and child interventions, educational/counseling interventions increased exclusive breastfeeding by 43% at 4-6 weeks and 137% at 6 months. Vitamin A supplementation (VAS) reduces all-cause mortality by 24% and results in a 14% reduction in the risk of infant mortality at 6 months. Intermittent iron supplementation in children reduces the risk of anemia by 49% and iron deficiency by 76%, and significantly improves hemoglobin and ferritin concentration. Preventive zinc supplementation in populations at risk of zinc deficiency decreases morbidity from childhood diarrhea and acute lower respiratory infections, and increases linear growth and weight gain among infants and young children. Among the supportive interventions, hand washing with soap significantly reduces diarrhea morbidity by 48%, though it depends on access to water. The effect of water treatment on diarrhea morbidity also appears similarly large with a 17% reduction. Recent research has established linkages of preconception interventions with improved maternal, perinatal and neonatal health outcomes, and it has been suggested that several proven interventions recommended during pregnancy may be even more effective if implemented before conception. These proven interventions, if scaled up have the potential to reduce the global burden of undernutrition substantially.

  6. Keeping Current. Library Media Specialists: Addressing the Student Health Epidemic

    ERIC Educational Resources Information Center

    Buddy, Juanita

    2005-01-01

    Health and educational leaders are sounding the alarm about the unhealthy condition of many students in America's K-12 schools. Each day, new scientific studies confirm that "The majority of American youth are sedentary and do not eat well. Sixteen percent of school-aged children and adolescents--or nine million--are overweight, a figure that has…

  7. Swimming Against the Current: Zebrafish Help Address Educational Challenges.

    PubMed

    Pickart, Michael A; Liang, Jennifer; Hutson, Lara; Pierret, Christopher

    2016-08-01

    Zebrafish can be important tools for learning and authentic student research. The broad zebrafish community is rich with examples to improve education for learners of all ages and geographical locales. This special collection of articles is presented with the hope of encouraging readers to reflect on the educational outcomes reported here and to consider new ways zebrafish may engage others to learn and grow. PMID:27333079

  8. 2015 ASHG Awards and Addresses

    PubMed Central

    2016-01-01

    Each year at the annual meeting of The American Society of Human Genetics (ASHG), addresses are given in honor of The Society and a number of award winners. A summary of each of these is given below. On the following pages, we have printed the presidential address and the addresses for the William Allan Award, the Curt Stern Award, and the Victor A. McKusick Leadership Award. Webcasts of these addresses, as well as those of many other presentations, can be found at http://www.ashg.org.

  9. Computational strategies to address chromatin structure problems

    NASA Astrophysics Data System (ADS)

    Perišić, Ognjen; Schlick, Tamar

    2016-06-01

    While the genetic information is contained in double helical DNA, gene expression is a complex multilevel process that involves various functional units, from nucleosomes to fully formed chromatin fibers accompanied by a host of various chromatin binding enzymes. The chromatin fiber is a polymer composed of histone protein complexes upon which DNA wraps, like yarn upon many spools. The nature of chromatin structure has been an open question since the beginning of modern molecular biology. Many experiments have shown that the chromatin fiber is a highly dynamic entity with pronounced structural diversity that includes properties of idealized zig-zag and solenoid models, as well as other motifs. This diversity can produce a high packing ratio and thus inhibit access to a majority of the wound DNA. Despite much research, chromatin’s dynamic structure has not yet been fully described. Long stretches of chromatin fibers exhibit puzzling dynamic behavior that requires interpretation in the light of gene expression patterns in various tissue and organisms. The properties of chromatin fiber can be investigated with experimental techniques, like in vitro biochemistry, in vivo imagining, and high-throughput chromosome capture technology. Those techniques provide useful insights into the fiber’s structure and dynamics, but they are limited in resolution and scope, especially regarding compact fibers and chromosomes in the cellular milieu. Complementary but specialized modeling techniques are needed to handle large floppy polymers such as the chromatin fiber. In this review, we discuss current approaches in the chromatin structure field with an emphasis on modeling, such as molecular dynamics and coarse-grained computational approaches. Combinations of these computational techniques complement experiments and address many relevant biological problems, as we will illustrate with special focus on epigenetic modulation of chromatin structure.

  10. EMIC-wave-moderated flux limitations of ring current energetic ion intensities in the multi-species plasmas of Earth's inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Mauk, B.

    2013-12-01

    One of the early sophisticated integrations of theory and observations of the space age was the development in 1966 of the integral Kennel-Petschek flux limit for trapped energetic electrons and ions within Earth's inner magnetosphere. Specifically, it was proposed that: 1) trapped particle distributions in the magnetic bottle configuration of the inner magnetosphere are intrinsically unstable to the generation various plasma waves and 2) ionospheric reflection of some waves back into the trapped populations leads to runaway growth of the waves and dramatic loss of particles for particle integral intensities that rise above a fairly rigidly specified upper limit. While there has been a long hiatus in utilization of the KP limit in inner magnetospheric research, there have been recent highly successful reconsiderations of more general forms of the KP limit for understanding radiation belt electron intensities and spectral shapes, resulting from improvements in theoretical tools. Such a reconsideration has not happened for energetic trapped ions, perhaps due to the perceived immense complexity of the generation of the Electromagnetic Ion Cyclotron (EMIC) waves, that scatter the energetic ions, for plasmas containing multiple ionic species (H, He, O). Here, a differential Kennel-Petschek (KP) flux limit for magnetospheric energetic ions is devised taking into account multiple ion species effects on the EMIC waves. This new theoretical approach is applied to measured Earth magnetosphere energetic ion spectra (~ keV to ~ 1 MeV) for radial positions (L) 3 to 6.7 RE. The flatness of the most intense spectral shapes for <100 keV indicate sculpting by just such a mechanism, but modifications of traditional KP parameters are needed to account for maximum intensities up to 5 times greater than expected. Future work using the Van Allen Probes mission will likely resolve outstanding uncertainties.

  11. Binary optics: Trends and limitations

    NASA Technical Reports Server (NTRS)

    Farn, Michael W.; Veldkamp, Wilfrid B.

    1993-01-01

    We describe the current state of binary optics, addressing both the technology and the industry (i.e., marketplace). With respect to the technology, the two dominant aspects are optical design methods and fabrication capabilities, with the optical design problem being limited by human innovation in the search for new applications and the fabrication issue being limited by the availability of resources required to improve fabrication capabilities. With respect to the industry, the current marketplace does not favor binary optics as a separate product line and so we expect that companies whose primary purpose is the production of binary optics will not represent the bulk of binary optics production. Rather, binary optics' more natural role is as an enabling technology - a technology which will directly result in a competitive advantage in a company's other business areas - and so we expect that the majority of binary optics will be produced for internal use.

  12. Binary optics: Trends and limitations

    NASA Astrophysics Data System (ADS)

    Farn, Michael W.; Veldkamp, Wilfrid B.

    1993-08-01

    We describe the current state of binary optics, addressing both the technology and the industry (i.e., marketplace). With respect to the technology, the two dominant aspects are optical design methods and fabrication capabilities, with the optical design problem being limited by human innovation in the search for new applications and the fabrication issue being limited by the availability of resources required to improve fabrication capabilities. With respect to the industry, the current marketplace does not favor binary optics as a separate product line and so we expect that companies whose primary purpose is the production of binary optics will not represent the bulk of binary optics production. Rather, binary optics' more natural role is as an enabling technology - a technology which will directly result in a competitive advantage in a company's other business areas - and so we expect that the majority of binary optics will be produced for internal use.

  13. Current limits and future challenges in the management of renal dysfunction in patients with cirrhosis: report from the International Club of Ascites.

    PubMed

    Angeli, Paolo; Sanyal, Arun; Moller, Soren; Alessandria, Carlo; Gadano, Adrian; Kim, Ray; Sarin, Shiv K; Bernardi, Mauro

    2013-01-01

    Advanced cirrhosis is often complicated by a multi organ failure syndrome which involves many different organs besides the liver. The high morbidity and mortality secondary to this clinical setting is often related to renal dysfunction, either alone or, more frequently, in combination with other organ dysfunction. A clear definition of renal dysfunction, an accurate differential diagnostic process of its different phenotypes as well as of full understanding of its pathophysiological mechanisms are crucial to the development of strategies for the management of this complication. This article is based either on the more recent knowledge on renal dysfunction in advanced cirrhosis or current opinions among the members of the International Club of Ascites (ICA) on the management of this complication, obtained through a survey and discussed during the EASL-ICA Joint Meeting in Berlin in March 2011. It reviews critically our current knowledge and it outlines future perspectives, on the management of renal dysfunction in patients with cirrhosis.

  14. Propagation In Matter Of Currents Of Relativistic Electrons Beyond The Alfven Limit, Produced In Ultra-High-Intensity Short-Pulse Laser-Matter Interactions

    NASA Astrophysics Data System (ADS)

    Batani, D.; Baton, S. D.; Manclossi, M.; Amiranoff, F.; Koenig, M.; Santos, J. J.; Martinolli, E.; Gremillet, L.; Popescu, H.; Antonicci, A.; Rousseaux, C.; Rabec Le Gloahec, M.; Hall, T.; Malka, V.; Cowan, T. E.; Stephens, R.; Key, M.; King, J.; Freeman, R.

    2004-12-01

    This paper reports the results of several experiments performed at the LULI laboratory (Palaiseau, France) concerning the propagation of large relativistic currents in matter from ultra-high-intensity laser pulse interaction with target. We present our results according to the type of diagnostics used in the experiments: 1) Kα emission and Kα imaging, 2) study of target rear side emission in the visible region, 3) time resolved optical shadowgraphy.

  15. Diffusion-limited current to an ion-selective membrane: The role of water splitting and an extended space charge region

    NASA Astrophysics Data System (ADS)

    Nielsen, Christoffer P.; Bruus, Henrik

    2013-11-01

    The study of ion-transport across an ion-selective membrane or to an ion-selective surface has found numerous applications in e.g. dialysis, desalination and electrochemistry. The classical 1D LEN (Local Electroneutrality) modeling of the problem has however proven to fall short in many ways, since neither the effect of a finite space charge or the influence of water ions (hydronium and hydroxide) is accounted for in this model. In this work we use a simple model assuming local equilibrium of the water dissociation reaction to model salt and water-ion transport across an ion-selective membrane. The developed numerical and analytical models include the effect of an extended space charge region, and yield current voltage curves and water-ion current versus salt ion current curves which are in qualitative agreement with experimental results. As a result of the analysis a number of simple scaling laws are derived. These are useful for characterizing systems with concentration polarization and allow for easy experimental testing of the model.

  16. Corruption of pharmaceutical markets: addressing the misalignment of financial incentives and public health.

    PubMed

    Gagnon, Marc-André

    2013-01-01

    This paper explains how the current architecture of the pharmaceutical markets has created a misalignment of financial incentives and public health that is a central cause of harmful practices. It explores three possible solutions to address that misalignment: taxes, increased financial penalties, and drug pricing based on value. Each proposal could help to partly realign financial incentives and public health. However, because of the limits of each proposal, there is no easy solution to fixing the problem of financial incentives.

  17. Low-cost and high-power-density resistive fault-current limiting elements using YBCO thin films and Au-Ag alloy shunt layers

    NASA Astrophysics Data System (ADS)

    Yamasaki, H.; Arai, K.; Furuse, M.; Kaiho, K.; Nakagawa, Y.

    2006-06-01

    We propose a new design for the high-temperature superconducting thin-film faultcurrent limiter (FCL), which uses high-resistivity Au-Ag alloy shunt layers instead of the pure gold (or silver) shunt layers conventionally used. An FCL element (5 mm wide and 40 mm long) with a YBCO thin film (THEVA) and a parallel inductively-wound shunt resistor successfully withstood very high electric field (> 44 Vpeak/cm) for 5 cycles (0.1 sec) after switching, and achieved a very high switching power density, ~2.0 kVA/cm2. We confirmed similar maximum tolerable electric field (>40 Vpeak/cm, limited by power supply) in a larger sample (1 cm × 6 cm). The composition of our FCL element is very simple, and the achieved power density is more than five times higher than conventional devices, which leads to a dramatic reduction in the amount of expensive superconducting thin films. We made a conceptual design and cost estimation of our FCL elements used in a typical 6.6 kV FCL.

  18. Evaluation of state-of-the-art imaging systems for in vivo monitoring of retinal structure in mice: current capabilities and limitations

    NASA Astrophysics Data System (ADS)

    Zhang, Pengfei; Zam, Azhar; Pugh, Edward N.; Zawadzki, Robert J.

    2014-02-01

    Animal models of human diseases play an important role in studying and advancing our understanding of these conditions, allowing molecular level studies of pathogenesis as well as testing of new therapies. Recently several non-invasive imaging modalities including Fundus Camera, Scanning Laser Ophthalmoscopy (SLO) and Optical Coherence Tomography (OCT) have been successfully applied to monitor changes in the retinas of the living animals in experiments in which a single animal is followed over a portion of its lifespan. Here we evaluate the capabilities and limitations of these three imaging modalities for visualization of specific structures in the mouse eye. Example images acquired from different types of mice are presented. Future directions of development for these instruments and potential advantages of multi-modal imaging systems are discussed as well.

  19. Cost-effective particulate control options at Potomac Electric Power Company's Dickerson Station: An integrated approach to current and future particulate limits

    SciTech Connect

    Christoffersen, S.W.; Rouse, G.T.; Krasnopoler, M.J.; Chapowski, J.A.

    1998-07-01

    The Dickerson Generating Station evaluated several particulate control options to identify the most cost-effective option. The study's goals were to: eliminate the particulate scrubber and its high maintenance costs, and incorporate flexibility for low-sulfur coal and possible stricter emission limits. Each of the three Dickerson 190 MW units has a small 37-year-old electrostatic precipitator and a wet particulate scrubber. The study evaluated alternatives to replace the scrubber and enhance ESP performance: Existing ESP alternatives--Extend height of existing ESP; Flue gas conditioning. Scrubber stream alternatives--Partial-flow ESP or pulse jet baghouse. Full-flow alternatives--Supplemental ESP; COHPAC baghouse; replacement ESP or baghouse. A technical and economic prescreening eliminated some of the options. Capital, operating, and life cycle costs were estimated for the remaining options to determine the most cost-effective alternative. This paper will present the technical and economic evaluations done for this study, including performance and costs.

  20. Astrophysical data on 5 eV to 1 keV radiation from the radiative decay of fundamental particles - Current limits and prospects for improvement

    NASA Technical Reports Server (NTRS)

    Bowyer, Stuart; Malina, Roger F.

    1986-01-01

    Line emission from the decay of fundamental particles, integrated over cosmological distances, can give rise to detectable spectral features in the diffuse astronomical background between 5 eV and 1 keV. Spectroscopic observations may allow these features to be separated from line emission from the numerous local sources of radiation. The current observational status and existing evidence for such features are reviewed. No definitive detections of nongalactic line features have been made. Several local sources of background mask the features at many wavelengths and confuse the interpretation of the data. No systematic spectral observations have been carried out to date. Upcoming experiments which can be expected to provide significantly better constraints on the presence of spectral features in the diffuse background from 5 eV to 1 keV are reviewed.

  1. Addressing problems of employee performance.

    PubMed

    McConnell, Charles R

    2011-01-01

    Employee performance problems are essentially of 2 kinds: those that are motivational in origin and those resulting from skill deficiencies. Both kinds of problems are the province of the department manager. Performance problems differ from problems of conduct in that traditional disciplinary processes ordinarily do not apply. Rather, performance problems are addressed through educational and remedial processes. The manager has a basic responsibility in ensuring that everything reasonable is done to help each employee succeed. There are a number of steps the manager can take to address employee performance problems.

  2. Limited World, Limited Rights.

    ERIC Educational Resources Information Center

    Hardin, Garrett

    The currently popular issue of natural rights is more complicated than many of its proponents realize. Natural rights, be they of an individual or a nation, do not exist within a social vacuum. When a person or nation asserts a natural right to something, the implication is that someone else is obligated to furnish it. Thus one person's right is a…

  3. Controlling Charge and Current Neutralization of an Ion Beam Pulse in a Background Plasma by Application of a Solenoidal Magnetic Field I: Weak Magnetic Field Limit

    SciTech Connect

    Kaganovich, I. D., Startsev, E. A., Sefkow, A. B., Davidson, R. C.

    2008-10-10

    Propagation of an intense charged particle beam pulse through a background plasma is a common problem in astrophysics and plasma applications. The plasma can effectively neutralize the charge and current of the beam pulse, and thus provides a convenient medium for beam transport. The application of a small solenoidal magnetic field can drastically change the self-magnetic and self- electric fields of the beam pulse, thus allowing effective control of the beam transport through the background plasma. An analytic model is developed to describe the self-magnetic field of a finite- length ion beam pulse propagating in a cold background plasma in a solenoidal magnetic field. The analytic studies show that the solenoidal magnetic field starts to infuence the self-electric and self-magnetic fields when ωce > ωpeβb, where ωce = eβ/mec is the electron gyrofrequency, ωpe is the electron plasma frequency, and βb = Vb/c is the ion beam velocity relative to the speed of light. This condition typically holds for relatively small magnetic fields (about 100G). Analytical formulas are derived for the effective radial force acting on the beam ions, which can be used to minimize beam pinching. The results of analytic theory have been verified by comparison with the simulation results obtained from two particle-in-cell codes, which show good agreement.

  4. Addressing Trauma in Substance Abuse Treatment

    ERIC Educational Resources Information Center

    Giordano, Amanda L.; Prosek, Elizabeth A.; Stamman, Julia; Callahan, Molly M.; Loseu, Sahar; Bevly, Cynthia M.; Cross, Kaitlin; Woehler, Elliott S.; Calzada, Richard-Michael R.; Chadwell, Katie

    2016-01-01

    Trauma is prevalent among clients with substance abuse issues, yet addictions counselors' training in trauma approaches is limited. The purpose of the current article is to provide pertinent information regarding trauma treatment including the use of assessments, empirically supported clinical approaches, self-help groups and the risk of vicarious…

  5. Addressing Phonological Questions with Ultrasound

    ERIC Educational Resources Information Center

    Davidson, Lisa

    2005-01-01

    Ultrasound can be used to address unresolved questions in phonological theory. To date, some studies have shown that results from ultrasound imaging can shed light on how differences in phonological elements are implemented. Phenomena that have been investigated include transitional schwa, vowel coalescence, and transparent vowels. A study of…

  6. Every Other Day. Keynote Address.

    ERIC Educational Resources Information Center

    Tiller, Tom

    Schools need to be reoriented and restructured so that what is taught and learned, and the way in which it is taught and learned, are better integrated with young people's real-world experiences. Many indicators suggest that the meaningful aspects of school have been lost in the encounter with modern times. The title of this address--"Every Other…

  7. State of the Lab Address

    SciTech Connect

    King, Alex

    2010-01-01

    In his third-annual State of the Lab address, Ames Laboratory Director Alex King called the past year one of "quiet but strong progress" and called for Ames Laboratory to continue to build on its strengths while responding to changing expectations for energy research.

  8. State of the Lab Address

    ScienceCinema

    King, Alex

    2016-07-12

    In his third-annual State of the Lab address, Ames Laboratory Director Alex King called the past year one of "quiet but strong progress" and called for Ames Laboratory to continue to build on its strengths while responding to changing expectations for energy research.

  9. Parametic Study of the current limit within a single driver-scaletransport beam line of an induction Linac for Heavy Ion Fusion

    SciTech Connect

    Prost, Lionel Robert

    2004-01-01

    The High Current Experiment (HCX) at Lawrence Berkeley National Laboratory is part of the US program that explores heavy-ion beam as the driver option for fusion energy production in an Inertial Fusion Energy (IFE) plant. The HCX is a beam transport experiment at a scale representative of the low-energy end of an induction linear accelerator driver. The primary mission of this experiment is to investigate aperture fill factors acceptable for the transport of space-charge-dominated heavy-ion beams at high intensity (line charge density ~0.2 μC/m) over long pulse durations (4 μs) in alternating gradient focusing lattices of electrostatic or magnetic quadrupoles. This experiment is testing transport issues resulting from nonlinear space-charge effects and collective modes, beam centroid alignment and steering, envelope matching, image charges and focusing field nonlinearities, halo and, electron and gas cloud effects. We present the results for a coasting 1 MeV K+ ion beam transported through ten electrostatic quadrupoles. The measurements cover two different fill factor studies (60% and 80% of the clear aperture radius) for which the transverse phase-space of the beam was characterized in detail, along with beam energy measurements and the first halo measurements. Electrostatic quadrupole transport at high beam fill factor (~80%) is achieved with acceptable emittance growth and beam loss. We achieved good envelope control, and re-matching may only be needed every ten lattice periods (at 80% fill factor) in a longer lattice of similar design. We also show that understanding and controlling the time dependence of the envelope parameters is critical to achieving high fill factors, notably because of the injector and matching section dynamics.

  10. Presidential address. Fatti Maschii Parole Femine.

    PubMed

    Murphy, G P

    1984-03-15

    The current role of the Society of Surgical Oncology has demonstrated leadership in the field of surgical oncology in both word and deed, as exemplified by the motto of the State of Maryland, adopted from the 1632 family seal of Lord Baltimore, "Fatti Maschii Parole Femine." The current emphasis on the need for clinical research on human cancers, and the education of surgeons in all aspects of various cancers is well founded in the writings and the addresses of Dr. James Ewing, the Society's founder. Our goals as a society for the next decade have been precisely defined and, as in all important national programs, made current and interfaced with corresponding priorities of the American Cancer Society and the National Cancer Institute. The Society, in three project areas, is: (1) assessing current progress in surgical oncology, as well as future manpower needs; (2) studying on a comprehensive basis the surgical practices in cancer patient management; and (3) surveying academic centers concerning the nature of current education and training of academic surgeons in clinical research. The Training Committee currently reviews and recognizes 2-year postresidency multidisciplinary training at several institutions, and the James Ewing Foundation has expanded its fiscal support of educational activities. This annual meeting marks an historic first signified by the conjoint sessions being held with other international surgical oncology societies.

  11. Addressing the underperformance of faculty and staff.

    PubMed

    Kenner, Carole; Pressler, Jana L

    2006-01-01

    Many new nursing leaders assuming work as deans, assistant deans, or interim deans have limited education, experience, or background to prepare them for the job. To assist new deans and those aspiring to be deans, the authors of this department, both deans, offer survival tips based on their personal experiences and insights. They address common issues, challenges, and opportunities that face academic executive teams, such as negotiating an executive contract, obtaining faculty lines, building effective work teams, managing difficult employees, and creating nimble organizational structure to respond to changing consumer, healthcare delivery, and community needs. The authors welcome counterpoint discussions with readers. PMID:17108781

  12. Addressing Barriers to Learning. Volume 11, Number 2. Spring 2006

    ERIC Educational Resources Information Center

    Center for Mental Health in Schools at UCLA, 2006

    2006-01-01

    This issue of the quarterly newsletter of the Center for Mental Health in Schools includes the following features and regular segments: (1) Concerns = Opportunities: Addressing Student Disengagement, Acting Out, and Dropouts by Moving in New Directions; (2) Info Sheet: Costs of Not Addressing Barriers to Learning; and (3) Current Status of Mental…

  13. High current induction linacs

    NASA Astrophysics Data System (ADS)

    Barletta, W.; Faltens, A.; Henestroza, E.; Lee, E.

    1994-07-01

    Induction linacs are among the most powerful accelerators in existence. They have accelerated electron bunches of several kiloamperes, and are being investigated as drivers for heavy ion driven inertial confinement fusion (HIF), which requires peak beam currents of kiloamperes and average beam powers of some tens of megawatts. The requirement for waste transmutation with an 800 MeV proton or deuteron beam with an average current of 50 mA and an average power of 40 MW lies midway between the electron machines and the heavy ion machines in overall difficulty. Much of the technology and understanding of beam physics carries over from the previous machines to the new requirements. The induction linac allows use of a very large beam aperture, which may turn out to be crucial to reducing beam loss and machine activation from the beam halo. The major issues addressed here are transport of high intensity beams, availability of sources, efficiency of acceleration, and the state of the needed technology for the waste treatment application. Because of the transformer-like action of an induction core and the accompanying magnetizing current, induction linacs make the most economic sense and have the highest efficiencies with large beam currents. Based on present understanding of beam transport limits, induction core magnetizing current requirements, and pulse modulators, the efficiencies could be very high. The study of beam transport at high intensities has been the major activity of the HIF community. Beam transport and sources are limiting at low energies but are not significant constraints at the higher energies. As will be shown, the proton beams will be space-charge-dominated, for which the emittance has only a minor effect on the overall beam diameter but does determine the density falloff at the beam edge.

  14. Optical addressing technique for a CMOS RAM

    NASA Technical Reports Server (NTRS)

    Wu, W. H.; Bergman, L. A.; Allen, R. A.; Johnston, A. R.

    1988-01-01

    Progress on optically addressing a CMOS RAM for a feasibility demonstration of free space optical interconnection is reported in this paper. The optical RAM chip has been fabricated and functional testing is in progress. Initial results seem promising. New design and SPICE simulation of optical gate cell (OGC) circuits have been carried out to correct the slow fall time of the 'weak pull down' OGC, which has been characterized experimentally. Methods of reducing the response times of the photodiodes and the associated circuits are discussed. Even with the current photodiode, it appears that an OGC can be designed with a performance that is compatible with a CMOS circuit such as the RAM.

  15. Current titles

    SciTech Connect

    1995-07-01

    This booklet is published for those interested in current research being conducted at the National Center for Electron Microscopy. The NCEM is a DOE-designated national user facility and is available at no charge to qualified researchers. Access is controlled by an external steering committee. Interested researchers may contact Gretchen Hermes at (510) 486-5006 or address below for a User`s Guide. Copies of available papers can be ordered from: Theda Crawford National Center for Electron Microscopy, Lawrence Berkeley Laboratory, One Cyclotron Rd., MS72, Berkeley, California, USA 94720.

  16. Identifying and Addressing Vaccine Hesitancy

    PubMed Central

    Kestenbaum, Lori A.; Feemster, Kristen A.

    2015-01-01

    In the 20th century, the introduction of multiple vaccines significantly reduced childhood morbidity, mortality, and disease outbreaks. Despite, and perhaps because of, their public health impact, an increasing number of parents and patients are choosing to delay or refuse vaccines. These individuals are described as vaccine hesitant. This phenomenon has developed due to the confluence of multiple social, cultural, political and personal factors. As immunization programs continue to expand, understanding and addressing vaccine hesitancy will be crucial to their successful implementation. This review explores the history of vaccine hesitancy, its causes, and suggested approaches for reducing hesitancy and strengthening vaccine acceptance. PMID:25875982

  17. Nanoscale content-addressable memory

    NASA Technical Reports Server (NTRS)

    Davis, Bryan (Inventor); Principe, Jose C. (Inventor); Fortes, Jose (Inventor)

    2009-01-01

    A combined content addressable memory device and memory interface is provided. The combined device and interface includes one or more one molecular wire crossbar memories having spaced-apart key nanowires, spaced-apart value nanowires adjacent to the key nanowires, and configurable switches between the key nanowires and the value nanowires. The combination further includes a key microwire-nanowire grid (key MNG) electrically connected to the spaced-apart key nanowires, and a value microwire-nanowire grid (value MNG) electrically connected to the spaced-apart value nanowires. A key or value MNGs selects multiple nanowires for a given key or value.

  18. Search for same-sign top-quark pair production at sqrt(s) = 7 TeV and limits on flavour changing neutral currents in the top sector

    SciTech Connect

    Chatrchyan, Serguei; et al.

    2011-08-01

    An inclusive search for same-sign top-quark pair production in pp collisions at sqrt(s) = 7 TeV is performed using a data sample recorded with the CMS detector in 2010, corresponding to an integrated luminosity of 35 inverse picobarns. This analysis is motivated by recent studies of p p-bar to t t-bar reporting mass-dependent forward-backward asymmetries larger than expected from the standard model. These asymmetries could be due to Flavor Changing Neutral Currents (FCNC) in the top sector induced by t-channel exchange of a massive neutral vector boson (Z'). Models with such a Z' also predict enhancement of same-sign top-pair production in pp or p p-bar collisions. Limits are set as a function of the Z' mass and its couplings to u and t quarks. These limits disfavour the FCNC interpretation of the Tevatron results.

  19. An addressable confocal microscope for functional imaging of neuronal activity

    NASA Astrophysics Data System (ADS)

    Bansal, Vivek

    2005-07-01

    The study of computation occurring in single neurons and small networks of interconnected neurons is often limited by (1) the number of sites that can be simultaneously probed with electrophysiology tools such as patch pipettes and (2) the recording speed of fluorescence imaging tools such as confocal or multiphoton microscopy. Even in the line scan mode of galvanometer-based scanners, where one scan dimension is sacrificed to gain overall speed, the effective frame rate is limited to less than 1 kHz with no flexibility in site selection. To overcome these limitations and allow the study of many sites throughout the dendritic arbor, we have developed an addressable confocal laser-scanning microscope that permits recording from user-selected sites-of-interest at high frame rates, in addition to conventional full frame imaging. Our system utilizes acousto-optic deflectors (AODs) in the illumination pathway to allow for rapid user-defined positioning of a focused laser spot. However, since AODs rely on diffraction to steer a laser beam, they cannot effectively descan the fluorescence emission spectrum as done in mirror-based systems which utilize reflection; this prevents the use of a stationary pinhole as a spatial filter. Instead, we implement an addressable spatial filter using a digital micromirror device (DMD) in conjunction with the AODs to achieve confocality. A registration algorithm synchronizes the AODs and DMD such that point illumination and point detection are always colocalized in conjugate image planes. The current version of the confocal system has a spatial resolution of ˜1 mum. Furthermore, by letting the user tailor which sites are visited, we have shown that recordings can be made at an aggregate frame rate of ˜40 kHz. We have successfully demonstrated that the system is capable of optical sectioning and thus exhibits the main advantage of a confocal microscope for light-scattering biological tissue. This property was used to create three

  20. IP address management : augmenting Sandia's capabilities through open source tools.

    SciTech Connect

    Nayar, R. Daniel

    2005-08-01

    Internet Protocol (IP) address management is an increasingly growing concern at Sandia National Laboratories (SNL) and the networking community as a whole. The current state of the available IP addresses indicates that they are nearly exhausted. Currently SNL doesn't have the justification to obtain more IP address space from Internet Assigned Numbers Authority (IANA). There must exist a local entity to manage and allocate IP assignments efficiently. Ongoing efforts at Sandia have been in the form of a multifunctional database application notably known as Network Information System (NWIS). NWIS is a database responsible for a multitude of network administrative services including IP address management. This study will explore the feasibility of augmenting NWIS's IP management capabilities utilizing open source tools. Modifications of existing capabilities to better allocate available IP address space are studied.

  1. New experiments elucidating the current limiting mechanisms of Ag-sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} tapes.

    SciTech Connect

    Anderson, J.W.; Babcock, S.E.; Cai, X.Y.; Dorris, S.E.; Feldmann, M.; Jiang, J.; Larbalestier, D.C.; Li, Q.; Parrell, J.A.; Parrella, R.; Polak, M.; Polyanskii, A.; Riley, G.N. Jr.; Rupich, M.; Wu, Y.

    1999-01-15

    Multiple current limiting mechanisms exist from the nanometer to millimeter scale in Ag-sheathed (Bi,Pb)-2223 tapes. Recent studies of the zero-field critical current density (J{sub c} (0T, 77K)), the irreversibility field (H*) and the crack microstructure elucidate these properties. We show that H*(77K) can vary significantly over the range {approximately}120-260 mT, independently of J{sub c} (0T, 77K). Cracks, actual or incipient, exist on the sub to several hundred micron scale. Surface magneto optical imaging of whole tapes, correlated to subsequent ultrasonic fracture analysis of. the bare 2223 filaments extracted by dissolving away the Ag shows that even composites having J{sub c} (0T, 77K) values of 60 kA/cm{sup 2} exhibit strong signs of unhealed rolling damage. These combined studies show that today's very best 2223 tapes are still far from full optimization.

  2. Addressing viral resistance through vaccines

    PubMed Central

    Laughlin, Catherine; Schleif, Amanda; Heilman, Carole A

    2015-01-01

    Antimicrobial resistance is a serious healthcare concern affecting millions of people around the world. Antiviral resistance has been viewed as a lesser threat than antibiotic resistance, but it is important to consider approaches to address this growing issue. While vaccination is a logical strategy, and has been shown to be successful many times over, next generation viral vaccines with a specific goal of curbing antiviral resistance will need to clear several hurdles including vaccine design, evaluation and implementation. This article suggests that a new model of vaccination may need to be considered: rather than focusing on public health, this model would primarily target sectors of the population who are at high risk for complications from certain infections. PMID:26604979

  3. Changing concepts: the presidential address.

    PubMed

    Weed, J C

    1974-09-01

    A discussion of conceptual change in areas related to fertility and medicine is presented in an address by the president of the American Fertility Society. Advances in technological research and medicine, particularly in steroids and reporductive physiology, have been the most readily acceptable changes. Cesarean section and surgical sterilization have also become increasingly accepted. Newer developments such as sperm banks, artificial insemination, and ovum transfer have created profound ethical, moral, and medical issued in human engineering research and evolutionary theory. The legalization of abortion has brought moral, ethical, and legal problems for many members of the medical profession. It is urged that the Society promote education of the people in reproductive function, sexual activity, and parental obligation while being acutely aware of the problems in influencing or altering human reproduction.

  4. Addressing Failures in Exascale Computing

    SciTech Connect

    Snir, Marc; Wisniewski, Robert; Abraham, Jacob; Adve, Sarita; Bagchi, Saurabh; Balaji, Pavan; Belak, J.; Bose, Pradip; Cappello, Franck; Carlson, Bill; Chien, Andrew; Coteus, Paul; DeBardeleben, Nathan; Diniz, Pedro; Engelmann, Christian; Erez, Mattan; Fazzari, Saverio; Geist, Al; Gupta, Rinku; Johnson, Fred; Krishnamoorthy, Sriram; Leyffer, Sven; Liberty, Dean; Mitra, Subhasish; Munson, Todd; Schreiber, Rob; Stearley, Jon; Van Hensbergen, Eric

    2014-01-01

    We present here a report produced by a workshop on Addressing failures in exascale computing' held in Park City, Utah, 4-11 August 2012. The charter of this workshop was to establish a common taxonomy about resilience across all the levels in a computing system, discuss existing knowledge on resilience across the various hardware and software layers of an exascale system, and build on those results, examining potential solutions from both a hardware and software perspective and focusing on a combined approach. The workshop brought together participants with expertise in applications, system software, and hardware; they came from industry, government, and academia, and their interests ranged from theory to implementation. The combination allowed broad and comprehensive discussions and led to this document, which summarizes and builds on those discussions.

  5. Addressing failures in exascale computing

    SciTech Connect

    Snir, Marc; Wisniewski, Robert W.; Abraham, Jacob A.; Adve, Sarita; Bagchi, Saurabh; Balaji, Pavan; Belak, Jim; Bose, Pradip; Cappello, Franck; Carlson, William; Chien, Andrew A.; Coteus, Paul; Debardeleben, Nathan A.; Diniz, Pedro; Engelmann, Christian; Erez, Mattan; Saverio, Fazzari; Geist, Al; Gupta, Rinku; Johnson, Fred; Krishnamoorthy, Sriram; Leyffer, Sven; Liberty, Dean; Mitra, Subhasish; Munson, Todd; Schreiber, Robert; Stearly, Jon; Van Hensbergen, Eric

    2014-05-01

    We present here a report produced by a workshop on “Addressing Failures in Exascale Computing” held in Park City, Utah, August 4–11, 2012. The charter of this workshop was to establish a common taxonomy about resilience across all the levels in a computing system; discuss existing knowledge on resilience across the various hardware and software layers of an exascale system; and build on those results, examining potential solutions from both a hardware and software perspective and focusing on a combined approach. The workshop brought together participants with expertise in applications, system software, and hardware; they came from industry, government, and academia; and their interests ranged from theory to implementation. The combination allowed broad and comprehensive discussions and led to this document, which summarizes and builds on those discussions.

  6. Light addressable photoelectrochemical cyanide sensor

    SciTech Connect

    Licht, S.; Myung, N.; Sun, Y.

    1996-03-15

    A sensor is demonstrated that is capable of spatial discrimination of cyanide with use of only a single stationary sensing element. Different spatial regions of the sensing element are light activated to reveal the solution cyanide concentration only at the point of illumination. In this light addressable photoelectrochemical (LAP) sensor the sensing element consists of an n-CdSe electrode immersed in solution, with the open-circuit potential determined under illumination. In alkaline ferro-ferri-cyanide solution, the open-circuit photopotential is highly responsive to cyanide, with a linear response of (120 mV) log [KCN]. LAP detection with a spatial resolution of {+-}1 mm for cyanide detection is demonstrated. The response is almost linear for 0.001-0.100 m cyanide with a resolution of 5 mV. 38 refs., 7 figs., 1 tab.

  7. Addressing the Special Education Crisis

    ERIC Educational Resources Information Center

    Amprey, Walter G.

    2005-01-01

    In the author's past work as a superintendent, and in his current capacity as an educational consultant, he has seen hundreds of dollars (per special education student) wasted in unnecessary costs and lost funding opportunities resulting from out-of-date, ineffective management systems. In addition to the fiscal implications, this imposes…

  8. Addressing violence against older women.

    PubMed

    2016-07-01

    Domestic abuse is widespread and indiscriminate, causing health-related concerns and mental health issues in older women. Research suggests their needs are not met by existing services. This article examines physical and mental health issues faced by older women as a result of abusive relationships, and the barriers that exist to seeking help. Healthcare professionals can facilitate therapeutic engagement of older women living with domestic abuse. Refuges and related interventions are limited, but developing a stepped approach, tailored to older women's needs, could help. PMID:27369732

  9. A region addresses patient safety.

    PubMed

    Feinstein, Karen Wolk; Grunden, Naida; Harrison, Edward I

    2002-06-01

    The Pittsburgh Regional Healthcare Initiative (PRHI) is a coalition of 35 hospitals, 4 major insurers, more than 30 major and small-business health care purchasers, dozens of corporate and civic leaders, organized labor, and partnerships with state and federal government all working together to deliver perfect patient care throughout Southwestern Pennsylvania. PRHI believes that in pursuing perfection, many of the challenges facing today's health care delivery system (eg, waste and error in the delivery of care, rising costs, frustration and shortage among clinicians and workers, financial distress, overcapacity, and lack of access to care) will be addressed. PRHI has identified patient safety (nosocomial infections and medication errors) and 5 clinical areas (obstetrics, orthopedic surgery, cardiac surgery, depression, and diabetes) as ideal starting points. In each of these areas of work, PRHI partners have assembled multifacility/multidisciplinary groups charged with defining perfection, establishing region-wide reporting systems, and devising and implementing recommended improvement strategies and interventions. Many design and conceptual elements of the PRHI strategy are adapted from the Toyota Production System and its Pittsburgh derivative, the Alcoa Business System. PRHI is in the proof-of-concept phase of development. PMID:12032502

  10. Gender: addressing a critical focus.

    PubMed

    Thornton, L; Wegner, M N

    1995-01-01

    The definition of gender was addressed at the Fourth World Conference on Women (Beijing, China). After extensive debate, the definition developed by the UN Population Fund in 1995 was adopted: "a set of qualities and behaviors expected from a female or male by society." The sustainability of family planning (FP) programs depends on acknowledgment of the role gender plays in contraceptive decision-making and use. For example, programs must consider the fact that women in many cultures do not make FP decisions without the consent of their spouse. AVSC is examining providers' gender-based ideas about clients and the effects of these views on the quality of reproductive health services. Questions such as how service providers can encourage joint responsibility for contraception without requiring spousal consent or how they can make men feel comfortable about using a male method in a society where FP is considered a woman's issue are being discussed. Also relevant is how service providers can discuss sexual matters openly with female clients in cultures that do not allow women to enjoy their sexuality. Another concern is the potential for physical violence to a client as a result of the provision of FP services. PMID:12294397

  11. Addressing Risks to Advance Mental Health Research

    PubMed Central

    Iltis, Ana S.; Misra, Sahana; Dunn, Laura B.; Brown, Gregory K.; Campbell, Amy; Earll, Sarah A.; Glowinski, Anne; Hadley, Whitney B.; Pies, Ronald; DuBois, James M.

    2015-01-01

    Objective Risk communication and management are essential to the ethical conduct of research, yet addressing risks may be time consuming for investigators and institutional review boards (IRBs) may reject study designs that appear too risky. This can discourage needed research, particularly in higher risk protocols or those enrolling potentially vulnerable individuals, such as those with some level of suicidality. Improved mechanisms for addressing research risks may facilitate much needed psychiatric research. This article provides mental health researchers with practical approaches to: 1) identify and define various intrinsic research risks; 2) communicate these risks to others (e.g., potential participants, regulatory bodies, society); 3) manage these risks during the course of a study; and 4) justify the risks. Methods As part of a National Institute of Mental Health (NIMH)-funded scientific meeting series, a public conference and a closed-session expert panel meeting were held on managing and disclosing risks in mental health clinical trials. The expert panel reviewed the literature with a focus on empirical studies and developed recommendations for best practices and further research on managing and disclosing risks in mental health clinical trials. IRB review was not required because there were no human subjects. The NIMH played no role in developing or reviewing the manuscript. Results Challenges, current data, practical strategies, and topics for future research are addressed for each of four key areas pertaining to management and disclosure of risks in clinical trials: identifying and defining risks, communicating risks, managing risks during studies, and justifying research risks. Conclusions Empirical data on risk communication, managing risks, and the benefits of research can support the ethical conduct of mental health research and may help investigators better conceptualize and confront risks and to gain IRB approval. PMID:24173618

  12. Do therapists address gender and power in infidelity? A feminist analysis of the treatment literature.

    PubMed

    Williams, Kirstee; Knudson-Martin, Carmen

    2013-07-01

    Sociocontextual factors such as gender and power play an important role in the etiology of affairs and in recovery from them, yet it is unclear how current treatment models address these issues. Drawing on feminist epistemology, this study utilized a grounded theory analysis of 29 scholarly articles and books on infidelity treatment published between 2000 and 2010 to identify the circumstances under which gender and power issues were or were not part of treatment. We found five conditions that limit attention to gender and power: (a) speaking (or assuming) as though partners are equal, (b) reframing infidelity as a relationship problem, (c) limiting discussion of societal context to background, (d) not considering how societal gender and power patterns impact relationship dynamics, and (e) limiting discussion of ethics on how to position around infidelity. Analysis explored how each occurred across three phases of couple therapy. The findings provide a useful foundation for a sociocontextual framework for infidelity treatment.

  13. Applying evolutionary biology to address global challenges

    PubMed Central

    Carroll, Scott P.; Jørgensen, Peter Søgaard; Kinnison, Michael T.; Bergstrom, Carl T.; Denison, R. Ford; Gluckman, Peter; Smith, Thomas B.; Strauss, Sharon Y.; Tabashnik, Bruce E.

    2014-01-01

    Two categories of evolutionary challenges result from escalating human impacts on the planet. The first arises from cancers, pathogens and pests that evolve too quickly, and the second from the inability of many valued species to adapt quickly enough. Applied evolutionary biology provides a suite of strategies to address these global challenges that threaten human health, food security, and biodiversity. This review highlights both progress and gaps in genetic, developmental and environmental manipulations across the life sciences that either target the rate and direction of evolution, or reduce the mismatch between organisms and human-altered environments. Increased development and application of these underused tools will be vital in meeting current and future targets for sustainable development. PMID:25213376

  14. Applying evolutionary biology to address global challenges.

    PubMed

    Carroll, Scott P; Jørgensen, Peter Søgaard; Kinnison, Michael T; Bergstrom, Carl T; Denison, R Ford; Gluckman, Peter; Smith, Thomas B; Strauss, Sharon Y; Tabashnik, Bruce E

    2014-10-17

    Two categories of evolutionary challenges result from escalating human impacts on the planet. The first arises from cancers, pathogens, and pests that evolve too quickly and the second, from the inability of many valued species to adapt quickly enough. Applied evolutionary biology provides a suite of strategies to address these global challenges that threaten human health, food security, and biodiversity. This Review highlights both progress and gaps in genetic, developmental, and environmental manipulations across the life sciences that either target the rate and direction of evolution or reduce the mismatch between organisms and human-altered environments. Increased development and application of these underused tools will be vital in meeting current and future targets for sustainable development.

  15. Extreme space weather studies: Addressing societal needs

    NASA Astrophysics Data System (ADS)

    Ngwira, C. M.

    2014-12-01

    Extreme space weather events can adversely impact the operations of critical modern-day technological infrastructure such as high-voltage electric power transmission grids. Understanding of coupled magnetosphere-ionosphere dynamics under extreme solar wind driving conditions is still a major challenge mainly because of a lack of data during such time intervals. This presentation will highlight some of the past and on-going investigations on extreme space weather events, and how these investigations are used to address societal needs. Particularly, I will describe how first principles physics-based 3-D global MHD models are playing a major role in advancing our knowledge on extreme geomagnetically induced currents. These MHD models represent a very important component of attempts to understand the response of the magnetosphere-ionosphere system to varying solar wind conditions.

  16. Engineering aspects of disruption current decay

    SciTech Connect

    Murray, J.G.

    1983-11-01

    Engineering features associated with the configuration of a tokamak can affect the amount of energy that produces melting and damage to the limiters or internal wall surfaces as the result of a major disruption. During the current decay period of a major thermal disruption, the energy that can damage a wall or limiter comes from the external magnetic field. By providing a good conducting torus near the plasma and increasing the plasma circuit resistance, this magnetic energy (transferred by way of the plasma circuit) can be minimized. This report addresses engineering design features to reduce the energy deposited on the inner torus surface that produces melting of the structures.

  17. Computer controlled performance mapping of thermionic converters: effect of collector, guard-ring potential imbalances on the observed collector current-density, voltage characteristics and limited range performance map of an etched-rhenium, niobium planar converter

    NASA Technical Reports Server (NTRS)

    Manista, E. J.

    1972-01-01

    The effect of collector, guard-ring potential imbalance on the observed collector-current-density J, collector-to-emitter voltage V characteristic was evaluated in a planar, fixed-space, guard-ringed thermionic converter. The J,V characteristic was swept in a period of 15 msec by a variable load. A computerized data acquisition system recorded test parameters. The results indicate minimal distortion of the J,V curve in the power output quadrant for the nominal guard-ring circuit configuration. Considerable distortion, along with a lowering of the ignited-mode striking voltage, was observed for the configuration with the emitter shorted to the guard ring. A limited-range performance map of an etched-rhenium, niobium, planar converter was obtained by using an improved computer program for the data acquisition system.

  18. WELCOME ADDRESS: Welcome Address for the 60th Yamada Conference

    NASA Astrophysics Data System (ADS)

    Fukuyama, Hidetoshi

    2006-12-01

    Ladies and Gentlemen On behalf of Yamada Science Foundation, I would like to extend our hearty welcome to all of you who are participating in the 60th Yamada Conference and International Symposium on Research in High Magnetic Fields particularly to those who have come a long way to Japan from various places all over the world. Yamada Science Foundation was founded in 1977 at Osaka, Japan. It develops its activities by giving support to the outstanding research projects in the basic natural sciences, especially in the interdisciplinary domains that bridge between well established research fields such as physics, chemistry, and biology. The Foundation also provides travel funds for scientists to visit or to go out of Japan in order to carry out international collaborative projects. It also holds conferences and workshops. Among these activities, one of the most important is the organization of Yamada Conferences, which are usually held two or three times a year on various topics which seem to be pioneering current research activities in natural sciences. Upon organizing Yamada Conferences, The Board of Directors of The Foundation put emphasis on the three symbolic English letter `I's. The first I stands for International, the second I means Interdisciplinary, and the third, perhaps the most important I symbolizes Innovative. As for this conference, I think it is in some sense interdisciplinary, because it deals with on one hand, the smallest scale of matter, the elementary particles while, on the other hand deals with the largest scale of matter, the universe, which are linked together. I also think many innovative ideas are presented in this conference. In this context, I believe this Conference is well suited to the scope of our Foundation. Another important aspect of holding Yamada Conference is to provide the forum of `Friendship' among the participants. We encourage all of you, particularly young scientists, to get acquainted with each other not only through hot

  19. Addressing the vaccine confidence gap.

    PubMed

    Larson, Heidi J; Cooper, Louis Z; Eskola, Juhani; Katz, Samuel L; Ratzan, Scott

    2011-08-01

    Vaccines--often lauded as one of the greatest public health interventions--are losing public confidence. Some vaccine experts have referred to this decline in confidence as a crisis. We discuss some of the characteristics of the changing global environment that are contributing to increased public questioning of vaccines, and outline some of the specific determinants of public trust. Public decision making related to vaccine acceptance is neither driven by scientific nor economic evidence alone, but is also driven by a mix of psychological, sociocultural, and political factors, all of which need to be understood and taken into account by policy and other decision makers. Public trust in vaccines is highly variable and building trust depends on understanding perceptions of vaccines and vaccine risks, historical experiences, religious or political affiliations, and socioeconomic status. Although provision of accurate, scientifically based evidence on the risk-benefit ratios of vaccines is crucial, it is not enough to redress the gap between current levels of public confidence in vaccines and levels of trust needed to ensure adequate and sustained vaccine coverage. We call for more research not just on individual determinants of public trust, but on what mix of factors are most likely to sustain public trust. The vaccine community demands rigorous evidence on vaccine efficacy and safety and technical and operational feasibility when introducing a new vaccine, but has been negligent in demanding equally rigorous research to understand the psychological, social, and political factors that affect public trust in vaccines. PMID:21664679

  20. Addressing the vaccine confidence gap.

    PubMed

    Larson, Heidi J; Cooper, Louis Z; Eskola, Juhani; Katz, Samuel L; Ratzan, Scott

    2011-08-01

    Vaccines--often lauded as one of the greatest public health interventions--are losing public confidence. Some vaccine experts have referred to this decline in confidence as a crisis. We discuss some of the characteristics of the changing global environment that are contributing to increased public questioning of vaccines, and outline some of the specific determinants of public trust. Public decision making related to vaccine acceptance is neither driven by scientific nor economic evidence alone, but is also driven by a mix of psychological, sociocultural, and political factors, all of which need to be understood and taken into account by policy and other decision makers. Public trust in vaccines is highly variable and building trust depends on understanding perceptions of vaccines and vaccine risks, historical experiences, religious or political affiliations, and socioeconomic status. Although provision of accurate, scientifically based evidence on the risk-benefit ratios of vaccines is crucial, it is not enough to redress the gap between current levels of public confidence in vaccines and levels of trust needed to ensure adequate and sustained vaccine coverage. We call for more research not just on individual determinants of public trust, but on what mix of factors are most likely to sustain public trust. The vaccine community demands rigorous evidence on vaccine efficacy and safety and technical and operational feasibility when introducing a new vaccine, but has been negligent in demanding equally rigorous research to understand the psychological, social, and political factors that affect public trust in vaccines.

  1. 500 V/200 A fault current limiter modules made of large-area MOD-YBa2Cu3O7 thin films with high-resistivity Au-Ag alloy shunt layers

    NASA Astrophysics Data System (ADS)

    Yamasaki, H.; Arai, K.; Kaiho, K.; Nakagawa, Y.; Sohma, M.; Kondo, W.; Yamaguchi, I.; Matsui, H.; Kumagai, T.; Natori, N.; Higuchi, N.

    2009-12-01

    We developed 500 Vrms/ 200 Arms superconducting thin-film fault current limiter (FCL) modules that can withstand high electric fields (E>30 Vrms cm-1) by using large-area YBa2Cu3O7 (YBCO) thin films with high-resistivity Au-Ag alloy shunt layers. Au-Ag alloy films about 60 nm thick were sputter-deposited on YBCO/CeO2/sapphire films (2.7 cm × 20 cm) prepared using a fluorine-free MOD method. Each 20 cm long Au-Ag/YBCO film was then divided into three segments (each ~5.7 cm long) by four Ag electrodes deposited on the Au-Ag layer, resulting in an effective length of 17 cm. The 500 V/200 A FCL modules were then fabricated by first connecting two of the segmented films in parallel using Ag-sheathed Bi-2223 superconducting tapes and then connecting in parallel an external resistor and a capacitor for each segment to protect the Au-Ag/YBCO film from hot spots. Switching tests using a short-circuit generator revealed that all the modules carried a superconducting ac current of >=237 Arms and that modules prepared with YBCO films having a relatively homogeneous critical current Ic distribution successfully withstood >=515 Vrms for five cycles without any damage. These results demonstrate that (a) the FCL modules fabricated here successfully achieved the rated current of 200 Arms and rated voltage of 500 Vrms and (b) total area of the YBCO films on sapphire substrates required for the 500 V/200 A (100 kV A) module was less than one-third that for conventional thin-film FCL modules that use gold shunt layers, leading to the significantly reduced cost of thin-film FCLs. Film damage due to hot spots depended on the difference in Ic between the two parallel-connected films and on the inhomogeneity of the Ic distribution in the film, and is most probably due to nonlinear current flows at the moment of quenching that cause local overheating.

  2. National Institutes of Health addresses the science of diversity.

    PubMed

    Valantine, Hannah A; Collins, Francis S

    2015-10-01

    The US biomedical research workforce does not currently mirror the nation's population demographically, despite numerous attempts to increase diversity. This imbalance is limiting the promise of our biomedical enterprise for building knowledge and improving the nation's health. Beyond ensuring fairness in scientific workforce representation, recruiting and retaining a diverse set of minds and approaches is vital to harnessing the complete intellectual capital of the nation. The complexity inherent in diversifying the research workforce underscores the need for a rigorous scientific approach, consistent with the ways we address the challenges of science discovery and translation to human health. Herein, we identify four cross-cutting diversity challenges ripe for scientific exploration and opportunity: research evidence for diversity's impact on the quality and outputs of science; evidence-based approaches to recruitment and training; individual and institutional barriers to workforce diversity; and a national strategy for eliminating barriers to career transition, with scientifically based approaches for scaling and dissemination. Evidence-based data for each of these challenges should provide an integrated, stepwise approach to programs that enhance diversity rapidly within the biomedical research workforce.

  3. National Institutes of Health addresses the science of diversity.

    PubMed

    Valantine, Hannah A; Collins, Francis S

    2015-10-01

    The US biomedical research workforce does not currently mirror the nation's population demographically, despite numerous attempts to increase diversity. This imbalance is limiting the promise of our biomedical enterprise for building knowledge and improving the nation's health. Beyond ensuring fairness in scientific workforce representation, recruiting and retaining a diverse set of minds and approaches is vital to harnessing the complete intellectual capital of the nation. The complexity inherent in diversifying the research workforce underscores the need for a rigorous scientific approach, consistent with the ways we address the challenges of science discovery and translation to human health. Herein, we identify four cross-cutting diversity challenges ripe for scientific exploration and opportunity: research evidence for diversity's impact on the quality and outputs of science; evidence-based approaches to recruitment and training; individual and institutional barriers to workforce diversity; and a national strategy for eliminating barriers to career transition, with scientifically based approaches for scaling and dissemination. Evidence-based data for each of these challenges should provide an integrated, stepwise approach to programs that enhance diversity rapidly within the biomedical research workforce. PMID:26392553

  4. National Institutes of Health addresses the science of diversity

    PubMed Central

    Valantine, Hannah A.; Collins, Francis S.

    2015-01-01

    The US biomedical research workforce does not currently mirror the nation’s population demographically, despite numerous attempts to increase diversity. This imbalance is limiting the promise of our biomedical enterprise for building knowledge and improving the nation’s health. Beyond ensuring fairness in scientific workforce representation, recruiting and retaining a diverse set of minds and approaches is vital to harnessing the complete intellectual capital of the nation. The complexity inherent in diversifying the research workforce underscores the need for a rigorous scientific approach, consistent with the ways we address the challenges of science discovery and translation to human health. Herein, we identify four cross-cutting diversity challenges ripe for scientific exploration and opportunity: research evidence for diversity’s impact on the quality and outputs of science; evidence-based approaches to recruitment and training; individual and institutional barriers to workforce diversity; and a national strategy for eliminating barriers to career transition, with scientifically based approaches for scaling and dissemination. Evidence-based data for each of these challenges should provide an integrated, stepwise approach to programs that enhance diversity rapidly within the biomedical research workforce. PMID:26392553

  5. Tumor-Infiltrating Lymphocyte Therapy: Addressing Prevailing Questions.

    PubMed

    Radvanyi, Laszlo G

    2015-01-01

    Autologous adoptive T-cell therapies have made tremendous strides over the last few years with excitement currently being generated by technologies that can reprogram T-cell specificities toward any desired antigen including chimeric antigen receptors and recombinant T-cell receptors. Time will tell whether these new genetically engineered T-cell technologies will be effective as advertised, especially in solid tumors, considering the limited availability of specific antigens and the difficulty in managing the unpredictable on-target, off-tissue toxicities. However, a form of T-cell therapy that has been utilized in patients more than any other and has left a lasting mark in the field is tumor-infiltrating lymphocytes (TILs). Tumor-infiltrating lymphocyte therapy has consistently yielded durable clinical responses in selected patients with metastatic melanoma and is now being increasingly applied to treat other solid tumors, including head and neck squamous cell carcinoma, cervical cancer, breast cancer, and lung cancer. Despite its long history in the clinic and key developments over the last few decades that have augmented response rates and have made TIL manufacturing more streamlined, a number of key outstanding conceptual questions remain to be answered in the TIL therapy field. In this review, we address critical questions, including the mechanism of action of TILs and active T-cell subsets, the current need for lymphoablative preconditioning, predictive biomarkers, the role of combination therapy such as checkpoint blockade, new excitement over the recognition of mutated antigens (the "mutanome") by TILs, and issues in developing TILs for nonmelanoma indications. In each case, we will critically discuss the main issues and concerns and how they can affect the eventual positioning of TIL therapy in the mainstream of cancer care. PMID:26588676

  6. Catholic Social Teaching: Addressing Globalization in Catholic Business Education

    ERIC Educational Resources Information Center

    Ball, James B.; Martinez, Zaida; Toyne, Brian

    2009-01-01

    Although business schools are increasingly aware of the importance of globalization in educating future business leaders, their business programs have addressed globalization from a limited perspective that fails to provide students with a broader understanding of its impact on societies and its moral consequences. The conventional approach to the…

  7. CCCC Chair's Address: Representing Ourselves, 2008

    ERIC Educational Resources Information Center

    Glenn, Cheryl

    2008-01-01

    This article presents the text of the author's address at the fifty-ninth annual convention of the Conference on College Composition and Communication (CCCC) in March 2008. In her address, the author picks up strands of previous Chairs' addresses and weaves them through the fabric of her remarks. What she hopes will give sheen to the fabric is her…

  8. 32 CFR 516.7 - Mailing addresses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Mailing addresses. 516.7 Section 516.7 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY AID OF CIVIL AUTHORITIES AND PUBLIC RELATIONS LITIGATION General § 516.7 Mailing addresses. Mailing addresses for organizations referenced...

  9. 47 CFR 13.10 - Licensee address.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Licensee address. 13.10 Section 13.10 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL COMMERCIAL RADIO OPERATORS General § 13.10 Licensee address. In accordance with § 1.923 of this chapter all applications must specify an address where...

  10. 75 FR 49813 - Change of Address

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-16

    ... COMMISSION 11 CFR Parts 9405, 9407, 9409, 9410, 9420, and 9428 Change of Address AGENCY: United States... Assistance Commission (EAC) is amending its regulations to reflect a change of address for its headquarters. This technical amendment is a nomenclature change that updates and corrects the address for...

  11. 77 FR 48429 - Commission Address Change

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-14

    ... HEALTH REVIEW COMMISSION 29 CFR Parts 2700, 2701, 2702, 2704, 2705, 2706 Commission Address Change AGENCY... to inform the public of the address change. DATES: This final rule will take effect on August 27... because the amendments are of a minor and administrative nature dealing with only a change in address....

  12. 47 CFR 97.23 - Mailing address.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Mailing address. 97.23 Section 97.23 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO... name and mailing address. The mailing address must be in an area where the amateur service is...

  13. 47 CFR 97.23 - Mailing address.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Mailing address. 97.23 Section 97.23 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO... name and mailing address. The mailing address must be in an area where the amateur service is...

  14. 47 CFR 97.23 - Mailing address.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Mailing address. 97.23 Section 97.23 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO... name and mailing address. The mailing address must be in an area where the amateur service is...

  15. 47 CFR 97.23 - Mailing address.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Mailing address. 97.23 Section 97.23 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO... name and mailing address. The mailing address must be in an area where the amateur service is...

  16. 47 CFR 97.23 - Mailing address.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Mailing address. 97.23 Section 97.23 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES AMATEUR RADIO... name and mailing address. The mailing address must be in an area where the amateur service is...

  17. An Integrated Assessment Approach to Address Artisanal and Small-Scale Gold Mining in Ghana.

    PubMed

    Basu, Niladri; Renne, Elisha P; Long, Rachel N

    2015-09-17

    Artisanal and small-scale gold mining (ASGM) is growing in many regions of the world including Ghana. The problems in these communities are complex and multi-faceted. To help increase understanding of such problems, and to enable consensus-building and effective translation of scientific findings to stakeholders, help inform policies, and ultimately improve decision making, we utilized an Integrated Assessment approach to study artisanal and small-scale gold mining activities in Ghana. Though Integrated Assessments have been used in the fields of environmental science and sustainable development, their use in addressing specific matter in public health, and in particular, environmental and occupational health is quite limited despite their many benefits. The aim of the current paper was to describe specific activities undertaken and how they were organized, and the outputs and outcomes of our activity. In brief, three disciplinary workgroups (Natural Sciences, Human Health, Social Sciences and Economics) were formed, with 26 researchers from a range of Ghanaian institutions plus international experts. The workgroups conducted activities in order to address the following question: What are the causes, consequences and correctives of small-scale gold mining in Ghana? More specifically: What alternatives are available in resource-limited settings in Ghana that allow for gold-mining to occur in a manner that maintains ecological health and human health without hindering near- and long-term economic prosperity? Several response options were identified and evaluated, and are currently being disseminated to various stakeholders within Ghana and internationally.

  18. An Integrated Assessment Approach to Address Artisanal and Small-Scale Gold Mining in Ghana

    PubMed Central

    Basu, Niladri; Renne, Elisha P.; Long, Rachel N.

    2015-01-01

    Artisanal and small-scale gold mining (ASGM) is growing in many regions of the world including Ghana. The problems in these communities are complex and multi-faceted. To help increase understanding of such problems, and to enable consensus-building and effective translation of scientific findings to stakeholders, help inform policies, and ultimately improve decision making, we utilized an Integrated Assessment approach to study artisanal and small-scale gold mining activities in Ghana. Though Integrated Assessments have been used in the fields of environmental science and sustainable development, their use in addressing specific matter in public health, and in particular, environmental and occupational health is quite limited despite their many benefits. The aim of the current paper was to describe specific activities undertaken and how they were organized, and the outputs and outcomes of our activity. In brief, three disciplinary workgroups (Natural Sciences, Human Health, Social Sciences and Economics) were formed, with 26 researchers from a range of Ghanaian institutions plus international experts. The workgroups conducted activities in order to address the following question: What are the causes, consequences and correctives of small-scale gold mining in Ghana? More specifically: What alternatives are available in resource-limited settings in Ghana that allow for gold-mining to occur in a manner that maintains ecological health and human health without hindering near- and long-term economic prosperity? Several response options were identified and evaluated, and are currently being disseminated to various stakeholders within Ghana and internationally. PMID:26393627

  19. Programming chemistry in DNA-addressable bioreactors.

    PubMed

    Fellermann, Harold; Cardelli, Luca

    2014-10-01

    We present a formal calculus, termed the chemtainer calculus, able to capture the complexity of compartmentalized reaction systems such as populations of possibly nested vesicular compartments. Compartments contain molecular cargo as well as surface markers in the form of DNA single strands. These markers serve as compartment addresses and allow for their targeted transport and fusion, thereby enabling reactions of previously separated chemicals. The overall system organization allows for the set-up of programmable chemistry in microfluidic or other automated environments. We introduce a simple sequential programming language whose instructions are motivated by state-of-the-art microfluidic technology. Our approach integrates electronic control, chemical computing and material production in a unified formal framework that is able to mimic the integrated computational and constructive capabilities of the subcellular matrix. We provide a non-deterministic semantics of our programming language that enables us to analytically derive the computational and constructive power of our machinery. This semantics is used to derive the sets of all constructable chemicals and supermolecular structures that emerge from different underlying instruction sets. Because our proofs are constructive, they can be used to automatically infer control programs for the construction of target structures from a limited set of resource molecules. Finally, we present an example of our framework from the area of oligosaccharide synthesis.

  20. Programming chemistry in DNA-addressable bioreactors

    PubMed Central

    Fellermann, Harold; Cardelli, Luca

    2014-01-01

    We present a formal calculus, termed the chemtainer calculus, able to capture the complexity of compartmentalized reaction systems such as populations of possibly nested vesicular compartments. Compartments contain molecular cargo as well as surface markers in the form of DNA single strands. These markers serve as compartment addresses and allow for their targeted transport and fusion, thereby enabling reactions of previously separated chemicals. The overall system organization allows for the set-up of programmable chemistry in microfluidic or other automated environments. We introduce a simple sequential programming language whose instructions are motivated by state-of-the-art microfluidic technology. Our approach integrates electronic control, chemical computing and material production in a unified formal framework that is able to mimic the integrated computational and constructive capabilities of the subcellular matrix. We provide a non-deterministic semantics of our programming language that enables us to analytically derive the computational and constructive power of our machinery. This semantics is used to derive the sets of all constructable chemicals and supermolecular structures that emerge from different underlying instruction sets. Because our proofs are constructive, they can be used to automatically infer control programs for the construction of target structures from a limited set of resource molecules. Finally, we present an example of our framework from the area of oligosaccharide synthesis. PMID:25121647

  1. Integrated Communications, Navigation and Surveillance Technologies Keynote Address

    NASA Technical Reports Server (NTRS)

    Lebacqz, J. Victor

    2004-01-01

    Slides for the Keynote Address present graphics to enhance the discussion of NASA's vision, the National Space Exploration Initiative, current Mars exploration, and aeronautics exploration. The presentation also focuses on development of an Air Transportation System and transformation from present systems.

  2. Addressing Educational Accountability and Political Legitimacy with Citizen Responsibility

    ERIC Educational Resources Information Center

    Stitzlein, Sarah M.

    2015-01-01

    In this essay, Sarah Stitzlein addresses a key current crisis in public education: accountability. Rather than centrally being about poor performance of teachers or inefficiency of schools, as we most often hear in media outlets and in education reform speeches, Stitzlein argues the crisis is at heart one about citizen responsibility and political…

  3. Can Innovation Save Gifted Education? 2010 NAGC Presidential Address

    ERIC Educational Resources Information Center

    Robinson, Ann

    2012-01-01

    Connecting innovation with gifted education is a necessity not only in the current political climate but also because it is a field with deeply held beliefs about the importance of problem solving, creativity, imagination, and invention--all critical components of innovation. In this address, the author focuses on three key ideas. First, she…

  4. Bullying in Schools: Addressing Desires, Not Only Behaviours

    ERIC Educational Resources Information Center

    Rigby, Ken

    2012-01-01

    Currently the main approach in responding to bullying in schools is to focus on undesired behaviours and to apply sanctions. This approach is often ineffective as well as failing to address the needs of children as persons as distinct from the behaviour they produce. A proposed alternative approach is to inquire into the motivation of children who…

  5. State Laws and Policies to Address Bullying in Schools

    ERIC Educational Resources Information Center

    Limber, Susan P.; Small, Mark A.

    2003-01-01

    This article focuses on the recent flurry of legislation in states to address bullying among school children. The primary purpose is to describe, compare, and contrast current state laws about bullying. Specifically, a description is provided of legislators' definitions of bullying and legislative findings about the nature and seriousness of…

  6. A European framework to address psychosocial hazards.

    PubMed

    Leka, Stavroula; Kortum, Evelyn

    2008-01-01

    Over the past decades, emphasis has been placed on the changing nature of work and new forms of risk that could negatively affect employee health and safety. These are mainly associated with new types of occupational hazards that have been termed psychosocial. Issues such as work-related stress, bullying and harassment are now receiving attention on a global basis and efforts have been made to address them at the workplace level. However, it has been acknowledged that despite developments of policy in this area, there still appear to be a broad science-policy gap and an even broader one between policy and practice. The WHO Network of Collaborating Centers in Occupational Health has, since the late 1990s, been supporting a dedicated program of work on psychosocial factors and work-related stress. Part of the Network's work is currently focusing on the translation of existing knowledge into practice in the area of psychosocial risk management. This program has identified that the optimum way forward lies in the development of a European framework for psychosocial risk management. This framework will serve as the basis for coordination of research activities and preventive action with an emphasis on evidence based interventions and best practice on an international basis. PMID:18408344

  7. THE IDEA IS TO USEMODIS IN CONJUNCTION WITH THE CURRENT LIMITED LANDSAT CAPABILITY, COMMERCIAL SATELLITES, ANDUNMANNED AERIAL VEHICLES (UAV), IN A MULTI-STAGE APPROACH TO MEET EPA INFORMATION NEEDS.REMOTE SENSING OVERVIEW: EPA CAPABILITIES, PRIORITY AGENCY APPLICATIONS, SENSOR/AIRCRAFT CAPABILITIES, COST CONSIDERATIONS, SPECTRAL AND SPATIAL RESOLUTIONS, AND TEMPORAL CONSIDERATIONS

    EPA Science Inventory

    EPA remote sensing capabilities include applied research for priority applications and technology support for operational assistance to clients across the Agency. The idea is to use MODIS in conjunction with the current limited Landsat capability, commercial satellites, and Unma...

  8. Limits to Open Class Performance?

    NASA Technical Reports Server (NTRS)

    Bowers, Albion H.

    2007-01-01

    This viewgraph presentation describes the limits to open class performance. The contents include: 1) Standard Class; 2) 15m/Racing Class; 3) Open Class; and 4) Design Solutions associated with assumptions, limiting parameters, airfoil performance, current trends, and analysis.

  9. Novel Duplicate Address Detection with Hash Function

    PubMed Central

    Song, GuangJia; Ji, ZhenZhou

    2016-01-01

    Duplicate address detection (DAD) is an important component of the address resolution protocol (ARP) and the neighbor discovery protocol (NDP). DAD determines whether an IP address is in conflict with other nodes. In traditional DAD, the target address to be detected is broadcast through the network, which provides convenience for malicious nodes to attack. A malicious node can send a spoofing reply to prevent the address configuration of a normal node, and thus, a denial-of-service attack is launched. This study proposes a hash method to hide the target address in DAD, which prevents an attack node from launching destination attacks. If the address of a normal node is identical to the detection address, then its hash value should be the same as the “Hash_64” field in the neighboring solicitation message. Consequently, DAD can be successfully completed. This process is called DAD-h. Simulation results indicate that address configuration using DAD-h has a considerably higher success rate when under attack compared with traditional DAD. Comparative analysis shows that DAD-h does not require third-party devices and considerable computing resources; it also provides a lightweight security resolution. PMID:26991901

  10. Novel Duplicate Address Detection with Hash Function.

    PubMed

    Song, GuangJia; Ji, ZhenZhou

    2016-01-01

    Duplicate address detection (DAD) is an important component of the address resolution protocol (ARP) and the neighbor discovery protocol (NDP). DAD determines whether an IP address is in conflict with other nodes. In traditional DAD, the target address to be detected is broadcast through the network, which provides convenience for malicious nodes to attack. A malicious node can send a spoofing reply to prevent the address configuration of a normal node, and thus, a denial-of-service attack is launched. This study proposes a hash method to hide the target address in DAD, which prevents an attack node from launching destination attacks. If the address of a normal node is identical to the detection address, then its hash value should be the same as the "Hash_64" field in the neighboring solicitation message. Consequently, DAD can be successfully completed. This process is called DAD-h. Simulation results indicate that address configuration using DAD-h has a considerably higher success rate when under attack compared with traditional DAD. Comparative analysis shows that DAD-h does not require third-party devices and considerable computing resources; it also provides a lightweight security resolution.

  11. Novel Duplicate Address Detection with Hash Function.

    PubMed

    Song, GuangJia; Ji, ZhenZhou

    2016-01-01

    Duplicate address detection (DAD) is an important component of the address resolution protocol (ARP) and the neighbor discovery protocol (NDP). DAD determines whether an IP address is in conflict with other nodes. In traditional DAD, the target address to be detected is broadcast through the network, which provides convenience for malicious nodes to attack. A malicious node can send a spoofing reply to prevent the address configuration of a normal node, and thus, a denial-of-service attack is launched. This study proposes a hash method to hide the target address in DAD, which prevents an attack node from launching destination attacks. If the address of a normal node is identical to the detection address, then its hash value should be the same as the "Hash_64" field in the neighboring solicitation message. Consequently, DAD can be successfully completed. This process is called DAD-h. Simulation results indicate that address configuration using DAD-h has a considerably higher success rate when under attack compared with traditional DAD. Comparative analysis shows that DAD-h does not require third-party devices and considerable computing resources; it also provides a lightweight security resolution. PMID:26991901

  12. Multi Sensor Approach to Address Sustainable Development

    NASA Technical Reports Server (NTRS)

    Habib, Shahid

    2007-01-01

    The main objectives of Earth Science research are many folds: to understand how does this planet operates, can we model her operation and eventually develop the capability to predict such changes. However, the underlying goals of this work are to eventually serve the humanity in providing societal benefits. This requires continuous, and detailed observations from many sources in situ, airborne and space. By and large, the space observations are the way to comprehend the global phenomena across continental boundaries and provide credible boundary conditions for the mesoscale studies. This requires a multiple sensors, look angles and measurements over the same spot in accurately solving many problems that may be related to air quality, multi hazard disasters, public health, hydrology and more. Therefore, there are many ways to address these issues and develop joint implementation, data sharing and operating strategies for the benefit of the world community. This is because for large geographical areas or regions and a diverse population, some sound observations, scientific facts and analytical models must support the decision making. This is crucial for the sustainability of vital resources of the world and at the same time to protect the inhabitants, endangered species and the ecology. Needless to say, there is no single sensor, which can answer all such questions effectively. Due to multi sensor approach, it puts a tremendous burden on any single implementing entity in terms of information, knowledge, budget, technology readiness and computational power. And, more importantly, the health of planet Earth and its ability to sustain life is not governed by a single country, but in reality, is everyone's business on this planet. Therefore, with this notion, it is becoming an impractical problem by any single organization/country to bear this colossal responsibility. So far, each developed country within their means has proceeded along satisfactorily in implementing

  13. USGS Science: Addressing Our Nation's Challenges

    USGS Publications Warehouse

    Larson, Tania M.

    2009-01-01

    With 6.6 billion people already living on Earth, and that number increasing every day, human influence on our planet is ever more apparent. Changes to the natural world combined with increasing human demands threaten our health and safety, our national security, our economy, and our quality of life. As a planet and a Nation, we face unprecedented challenges: loss of critical and unique ecosystems, the effects of climate change, increasing demand for limited energy and mineral resources, increasing vulnerability to natural hazards, the effects of emerging diseases on wildlife and human health, and growing needs for clean water. The time to respond to these challenges is now, but policymakers and decisionmakers face difficult choices. With competing priorities to balance, and potentially serious - perhaps irreversible - consequences at stake, our leaders need reliable scientific information to guide their decisions. As the Nation's earth and natural science agency, the USGS monitors and conducts scientific research on natural hazards and resources and how these elements and human activities influence our environment. Because the challenges we face are complex, the science needed to better understand and deal with these challenges must reflect the complex interplay among natural and human systems. With world-class expertise in biology, geology, geography, hydrology, geospatial information, and remote sensing, the USGS is uniquely capable of conducting the comprehensive scientific research needed to better understand the interdependent interactions of Earth's systems. Every day, the USGS helps decisionmakers to minimize loss of life and property, manage our natural resources, and protect and enhance our quality of life. This brochure provides examples of the challenges we face and how USGS science helps decisionmakers to address these challenges.

  14. Addressing Free Radical Oxidation in Acne Vulgaris

    PubMed Central

    Criscito, Maressa C.; Schlesinger, Todd E.; Verdicchio, Robert; Szoke, Ernest

    2016-01-01

    Objective: Comparatively little attention has been paid to the role of free radical oxidation in acne vulgaris. Here, using the traditional abnormalities cited for acne, the authors address the role of free radical oxidation throughout the pathogenesis by detailing the chemistry that may contribute to clinical changes. To probe the effects of free radical oxidation and test an antioxidant, they conducted a preliminary study of topically applied vitamin E. Methods: Seventeen patients with mild-to-moderate acne vulgaris were evaluated over an eight-week period in two private dermatology practices in this open-label study. All patients enrolled were on the same baseline regimen of salicylic acid and benzoyl peroxide. This regimen was then supplemented with topical vitamin E in sunflower seed oil. Results: At the end of the eight-week period, all patients demonstrated clinical improvement, as indicated by a reduction in the number of lesions and global mean difference. A statistically significant reduction was noted as early as Week 2. Enrolled patients also expressed a positive experience due to good tolerability and easy application. Conclusion: Although the exact pathogenesis of acne vulgaris remains unknown, the presence of excessive reactive oxygen species can be implicated in each of the major abnormalities involved. This presence, along with the positive results of the authors’ preliminary study, demonstrates the need for more exploration on the use of topical antioxidants in limiting free radical oxidation in the acne model. This paper is designed to stimulate academic discussion regarding a new way of thinking about the disease state of acne. PMID:26962389

  15. Identification, Assessment and Programming System for Students of Limited English Proficiency: A Systems Manual.

    ERIC Educational Resources Information Center

    Hawaii State Dept. of Education, Honolulu. Office of Instructional Services.

    The Hawaii State Department of Education's compliance plan for serving the special needs of minority students of limited English proficiency includes current policies, procedures, and program implementation specifications. The procedures address: surveys of newly enrolled students, English and native language proficiency assessment, program…

  16. Public health approach to address maternal mortality.

    PubMed

    Rai, Sanjay K; Anand, K; Misra, Puneet; Kant, Shashi; Upadhyay, Ravi Prakash

    2012-01-01

    Reducing maternal mortality is one of the major challenges to health systems worldwide, more so in developing countries that account for nearly 99% of these maternal deaths. Lack of a standard method for reporting of maternal death poses a major hurdle in making global comparisons. Currently much of the focus is on documenting the "number" of maternal deaths and delineating the "medical causes" behind these deaths. There is a need to acknowledge the social correlates of maternal deaths as well. Investigating and in-depth understanding of each maternal death can provide indications on practical ways of addressing the problem. Death of a mother has serious implications for the child as well as other family members and to prevent the same, a comprehensive approach is required. This could include providing essential maternal care, early management of complications and good quality intrapartum care through the involvement of skilled birth attendants. Ensuring the availability, affordability, and accessibility of quality maternal health services, including emergency obstetric care (EmOC) would prove pivotal in reducing the maternal deaths. To increase perceived seriousness of the community regarding maternal health, a well-structured awareness campaign is needed with importance be given to avoid adolescent pregnancy as well. Initiatives like Janani Surakhsha Yojna (JSY) that have the potential to improve maternal health needs to be strengthened. Quality assessments should form an essential part of all services that are directed toward improving maternal health. Further, emphasis needs to be given on research by involving multiple allied partners, with the aim to develop a prioritized, coordinated, and innovative research agenda for women's health. PMID:23229211

  17. Public Address Systems. Specifications - Installation - Operation.

    ERIC Educational Resources Information Center

    Palmer, Fred M.

    Provisions for public address in new construction of campus buildings (specifications, installations, and operation of public address systems), are discussed in non-technical terms. Consideration is given to microphones, amplifiers, loudspeakers and the placement and operation of various different combinations. (FS)

  18. Addressing Standards and Assessments on the IEP.

    ERIC Educational Resources Information Center

    Thompson, Sandra J.; Thurlow, Martha L.; Esler, Amy; Whetstone, Patti J.

    2001-01-01

    A study that examined state Individualized Education Program (IEP) forms found that out of the 41 with IEP forms, only 5 specifically addressed educational standards on their forms. Thirty-one states addressed the general curriculum on their IEP forms and 30 states listed three or more options for assessment participation. (Contains nine…

  19. History Forum Addresses Creation/Evolution Controversy.

    ERIC Educational Resources Information Center

    Schweinsberg, John

    1997-01-01

    A series of programs entitled Creationism and Evolution: The History of a Controversy was presented at the University of Alabama in Huntsville. The controversy was addressed from an historical and sociological, rather than a scientific perspective. Speakers addressed the evolution of scientific creationism, ancient texts versus sedimentary rocks…

  20. 16 CFR 1000.4 - Commission address.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Commission address. 1000.4 Section 1000.4 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION GENERAL COMMISSION ORGANIZATION AND FUNCTIONS § 1000.4 Commission address. The principal Offices of the Commission are at 4330 East West...