Engineering data exchange.

PubMed

Moore, M

2001-11-01

Mount Clemens General Hospsital, Mount Clemens, Mich. performance anomalies due to multiple interfaces with separate systems. implementation of an interface engine. improved management of data exchange among disparate systems. up-front studies of vendor offerings, potential problems, and long-term needs.

Potential of vegetable oils for lubricants

USDA-ARS?s Scientific Manuscript database

Vegetable oils offer significant advantages in terms of resource renewability, biodegradability, and comparable performance properties to petroleum-based products. The petroleum-based lubricants render unfavorable impact on the environment. With the growing environmental concerns, seed oils are find...

Recent Observations on the Performance of Hybrid Ceramic Tribo-Contacts

NASA Astrophysics Data System (ADS)

Buttery, M.; Cropper, M.; Wardzinski, B.; Lewis, S.; McLaren, S.; Kreuser, J.

2015-09-01

Hybrid ceramic ball bearings offer great promise in space applications but have not been rapidly adopted by industry perhaps partly due to the relatively low amount of published data on specific in-vacuum performance. Such bearings, having, typically, silicon nitride balls and 440C or high nitrogen steel (e.g. X30) raceways offer the potential for long life and low torque noise due a combination of chemical inertness, high hardness and the extremely smooth surfaces produced in ceramic balls. Though initial benefits were foreseen for high speed applications, the potential for reduced adhesive forces and wear in conditions of marginal lubrication, and for improvements in lubricant lifetime in long life applications limited by oil tribo-degradation render hybrid ceramic bearings more generally attractive.This paper draws together a number of experimental studies carried out at Pin-on-Disc (POD), Spiral Orbit Tribometer (SOT) and bearing-level recently at ESTL.

Theorizing Strategic Human Resource Development: Linking Financial Performance and Sustainable Competitive Advantage

ERIC Educational Resources Information Center

Hu, Po

2007-01-01

This paper is to explore potential new underlying theory of strategic human resource development based on critiques of current theoretical foundations of HRD. It offers a new definition and model of Strategic HRD based on resource-based view of firm and human resource, with linkage to financial performance and competitiveness. Proposed new model…

The undermining effect of facial attractiveness on brain responses to fairness in the Ultimatum Game: an ERP study

PubMed Central

Ma, Qingguo; Hu, Yue; Jiang, Shushu; Meng, Liang

2015-01-01

To investigate the time course of the neural processing of facial attractiveness and its influence on fairness consideration during social interactions, event-related potentials (ERP) were recorded from 21 male subjects performing a two-person Ultimatum Game (UG). During this bargaining game, the male subjects played responders who decided whether to accept offers from female proposers, whose facial images (grouped as “attractive” and “unattractive”) were presented prior to the offer presentation. The behavioral data demonstrated that the acceptance ratio increased with the fairness level of the offers and, more importantly, the subjects were more likely to accept unfair offers when presented with the attractive-face condition compared with the unattractive-face condition. The reaction times (RTs) for five offers (1:9, 2:8, 3:7, 4:6, and 5:5) in the unattractive-face condition were not significantly different. In contrast, the subjects reacted slower to the attractive proposers' unfair offers and quicker to fair offers. The ERP analysis of the face presentation demonstrated a decreased early negativity (N2) and enhanced late positive potentials (LPPs) elicited by the attractive faces compared with the unattractive faces. In addition, the feedback-related negativity (FRN) in response to an offer presentation was not significantly different for the unfair (1:9 and 2:8) and fair (4:6 and 5:5) offers in the attractive-face condition. However, the unfair offers generated larger FRNs compared with the fair offers in the unattractive-face condition (consistent with prior studies). A similar effect was identified for P300. The present study demonstrated an undermining effect of proposer facial attractiveness on responder consideration of offer fairness during the UG. PMID:25805967

Nuclear Radiation Tolerance of Single Crystal Aluminum Nitride Ultrasonic Transducer

NASA Astrophysics Data System (ADS)

Reinhard, Brian; Tittmann, Bernhard R.; Suprock, Andrew

Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models, (Rempe et al., 2011; Kazys et al., 2005). These efforts are limited by the lack of identified ultrasonic transducer materials capable of long term performance under irradiation test conditions. To address this need, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate the performance of promising magnetostrictive and piezoelectric transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 1021 n/cm2. The irradiation is also supported by a multi-National Laboratory collaboration funded by the Nuclear Energy Enabling Technologies Advanced Sensors and Instrumentation (NEET ASI) program. The results from this irradiation, which started in February 2014, offer the potential to enable the development of novel radiation tolerant ultrasonic sensors for use in Material Testing Reactors (MTRs). As such, this test is an instrumented lead test and real-time transducer performance data is collected along with temperature and neutron and gamma flux data. Hence, results from this irradiation offer the potential to bridge the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers. To date, very encouraging results have been attained as several transducers have continued to operate under irradiation. The irradiation is ongoing and will continue to approximately mid-2015.

Industrial potential, uses, and performance of sputtered and ion plated films

NASA Technical Reports Server (NTRS)

Spalvins, T.

1979-01-01

The sputtering and ion plating technology is reviewed in terms of their potential, uses and performance. It offers the greatest flexibility in coating preparation, since coatings can be tailored in any preferred chemical combination, and graded type interfaces (ceramic to metal seals) can be formed. Sputtered and ion plated film characteristics such as the degree of adherence, coherence and morphological growth which contribute to film performance and reliability are described and illustrated as used in practice. It is concluded that the potential future of sputtered and ion plated films for industrial applications will depend primarily upon greater comprehension of materials selection, possible elimination of restrictions for coating/substrate combinations and the awareness of utilizing the proper deposition parameters.

Exploratory evaluation of ceramics for automobile thermal reactors

NASA Technical Reports Server (NTRS)

Stone, P. L.; Blankenship, C. P.

1972-01-01

An exploratory evaluation of ceramics for automobile thermal reactors was conducted. Potential ceramic materials were evaluated in several reactor designs using both engine dynamometer and vehicle road tests. Silicon carbide contained in a corrugated metal support structure exhibited the best performance lasting over 800 hours in engine dynamometer tests and over 15,000 miles (24,200 km) of vehicle road tests. Reactors containing glass-ceramic components did not perform as well as silicon carbide. But the glass-ceramics still offer good potential for reactor use. The results of this study are considered to be a reasonable demonstration of the potential use of ceramics in thermal reactors.

High-Performance Thermoelectric Semiconductors

NASA Technical Reports Server (NTRS)

Fleurial, Jean-Pierre; Caillat, Thierry; Borshchevsky, Alexander

1994-01-01

Figures of merit almost double current state-of-art thermoelectric materials. IrSb3 is semiconductor found to exhibit exceptional thermoelectric properties. CoSb3 and RhSb3 have same skutterudite crystallographic structure as IrSb3, and exhibit exceptional transport properties expected to contribute to high thermoelectric performance. These three compounds form solid solutions. Combination of properties offers potential for development of new high-performance thermoelectric materials for more efficient thermoelectric power generators, coolers, and detectors.

ATLAS and LHC computing on CRAY

NASA Astrophysics Data System (ADS)

Sciacca, F. G.; Haug, S.; ATLAS Collaboration

2017-10-01

Access and exploitation of large scale computing resources, such as those offered by general purpose HPC centres, is one important measure for ATLAS and the other Large Hadron Collider experiments in order to meet the challenge posed by the full exploitation of the future data within the constraints of flat budgets. We report on the effort of moving the Swiss WLCG T2 computing, serving ATLAS, CMS and LHCb, from a dedicated cluster to the large Cray systems at the Swiss National Supercomputing Centre CSCS. These systems do not only offer very efficient hardware, cooling and highly competent operators, but also have large backfill potentials due to size and multidisciplinary usage and potential gains due to economy at scale. Technical solutions, performance, expected return and future plans are discussed.

Potential Astrophysics Science Missions Enabled by NASA's Planned Ares V

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Thronson, Harley; Langhoff, Stepheni; Postman, Marc; Lester, Daniel; Lillie, Chuck

2009-01-01

NASA s planned Ares V cargo vehicle with its 10 meter diameter fairing and 60,000 kg payload mass to L2 offers the potential to launch entirely new classes of space science missions such as 8-meter monolithic aperture telescopes, 12- meter aperture x-ray telescopes, 16 to 24 meter segmented telescopes and highly capable outer planet missions. The paper will summarize the current Ares V baseline performance capabilities and review potential mission concepts enabled by these capabilities.

VERIFYING THE PERFORMANCE OF PESTICIDE SPRAY DRIFT REDUCTION TECHNOLOGIES

EPA Science Inventory

Application of pesticide sprays usually results in formation of small spray droplets which can drift with air currents to nearby sensitive sites. A number of technologies offer the potential to reduce the amount of spray drift from pesticide applications. Acceptance and use of ...

The development of efficient coding for an electronic mail system

NASA Technical Reports Server (NTRS)

Rice, R. F.

1983-01-01

Techniques for efficiently representing scanned electronic documents were investigated. Major results include the definition and preliminary performance results of a Universal System for Efficient Electronic Mail (USEEM), offering a potential order of magnitude improvement over standard facsimile techniques for representing textual material.

Proximity Link Design and Performance Options for a Mars Areostationary Relay Satellite

NASA Technical Reports Server (NTRS)

Edwards, Charles D.; Bell, David J.; Biswas, Abhijit; Cheung, Kar-Ming; Lock, Robert E.

2016-01-01

Current and near-term Mars relay telecommunications services are provided by a set of NASA and ESA Mars science orbiters equipped with UHF relay communication payloads employing operationally simple low-gain antennas. These have been extremely successful in supporting a series of landed Mars mission, greatly increasing data return relative to direct-to-Earth lander links. Yet their relay services are fundamentally constrained by the short contact times available from the selected science orbits. Future Mars areostationary orbiters, flying in circular, equatorial, 1- sol orbits, offer the potential for continuous coverage of Mars landers and rovers, radically changing the relay support paradigm. Achieving high rates on the longer slant ranges to areostationary altitude will require steered, high-gain links. Both RF and optical options exist for achieving data rates in excess of 100 Mb/s. Several point designs offer a measure of potential user burden, in terms of mass, volume, power, and pointing requirements for user relay payloads, as a function of desired proximity link performance.

Cardiac PET/CT for the Evaluation of Known or Suspected Coronary Artery Disease

PubMed Central

Murthy, Venkatesh L.

2011-01-01

Positron emission tomography (PET) is increasingly being applied in the evaluation of myocardial perfusion. Cardiac PET can be performed with an increasing variety of cyclotron- and generator-produced radiotracers. Compared with single photon emission computed tomography, PET offers lower radiation exposure, fewer artifacts, improved spatial resolution, and, most important, improved diagnostic performance. With its capacity to quantify rest–peak stress left ventricular systolic function as well as coronary flow reserve, PET is superior to other methods for the detection of multivessel coronary artery disease and, potentially, for risk stratification. Coronary artery calcium scoring may be included for further risk stratification in patients with normal perfusion imaging findings. Furthermore, PET allows quantification of absolute myocardial perfusion, which also carries substantial prognostic value. Hybrid PET–computed tomography scanners allow functional evaluation of myocardial perfusion combined with anatomic characterization of the epicardial coronary arteries, thereby offering great potential for both diagnosis and management. Additional studies to further validate the prognostic value and cost effectiveness of PET are warranted. © RSNA, 2011 PMID:21918042

A taxonomy of accountable care organizations for policy and practice.

PubMed

Shortell, Stephen M; Wu, Frances M; Lewis, Valerie A; Colla, Carrie H; Fisher, Elliott S

2014-12-01

To develop an exploratory taxonomy of Accountable Care Organizations (ACOs) to describe and understand early ACO development and to provide a basis for technical assistance and future evaluation of performance. Data from the National Survey of Accountable Care Organizations, fielded between October 2012 and May 2013, of 173 Medicare, Medicaid, and commercial payer ACOs. Drawing on resource dependence and institutional theory, we develop measures of eight attributes of ACOs such as size, scope of services offered, and the use of performance accountability mechanisms. Data are analyzed using a two-step cluster analysis approach that accounts for both continuous and categorical data. We identified a reliable and internally valid three-cluster solution: larger, integrated systems that offer a broad scope of services and frequently include one or more postacute facilities; smaller, physician-led practices, centered in primary care, and that possess a relatively high degree of physician performance management; and moderately sized, joint hospital-physician and coalition-led groups that offer a moderately broad scope of services with some involvement of postacute facilities. ACOs can be characterized into three distinct clusters. The taxonomy provides a framework for assessing performance, for targeting technical assistance, and for diagnosing potential antitrust violations. © Health Research and Educational Trust.

Wave Rotor Research and Technology Development

NASA Technical Reports Server (NTRS)

Welch, Gerard E.

1998-01-01

Wave rotor technology offers the potential to increase the performance of gas turbine engines significantly, within the constraints imposed by current material temperature limits. The wave rotor research at the NASA Lewis Research Center is a three-element effort: 1) Development of design and analysis tools to accurately predict the performance of wave rotor components; 2) Experiments to characterize component performance; 3) System integration studies to evaluate the effect of wave rotor topping on the gas turbine engine system.

Content Analysis of Informed Consent for Whole Genome Sequencing Offered by Direct-to-Consumer Genetic Testing Companies.

PubMed

Niemiec, Emilia; Borry, Pascal; Pinxten, Wim; Howard, Heidi Carmen

2016-12-01

Whole exome sequencing (WES) and whole genome sequencing (WGS) have become increasingly available in the research and clinical settings and are now also being offered by direct-to-consumer (DTC) genetic testing (GT) companies. This offer can be perceived as amplifying the already identified concerns regarding adequacy of informed consent (IC) for both WES/WGS and the DTC GT context. We performed a qualitative content analysis of Websites of four companies offering WES/WGS DTC regarding the following elements of IC: pre-test counseling, benefits and risks, and incidental findings (IFs). The analysis revealed concerns, including the potential lack of pre-test counseling in three of the companies studied, missing relevant information in the risks and benefits sections, and potentially misleading information for consumers. Regarding IFs, only one company, which provides opportunistic screening, provides basic information about their management. In conclusion, some of the information (and related practices) present on the companies' Web pages salient to the consent process are not adequate in reference to recommendations for IC for WGS or WES in the clinical context. Requisite resources should be allocated to ensure that commercial companies are offering high-throughput sequencing under responsible conditions, including an adequate consent process. © 2016 WILEY PERIODICALS, INC.

Platinum Nickel Nanowires as Methanol Oxidation Electrocatalysts

DOE PAGES

Alia, Shaun M.; Pylypenko, Svitlana; Neyerlin, Kenneth C.; ...

2015-08-27

We investigated platinum(Pt) nickel (Ni) nanowires (PtNiNWs) as methanol oxidation reaction (MOR) catalysts in rotating disk electrode (RDE) half-cells under acidic conditions. Pt-ruthenium (Ru) nanoparticles have long been the state of the art MOR catalyst for direct methanol fuel cells (DMFCs) where Ru provides oxophilic sites, lowering the potential for carbon monoxide oxidation and the MOR onset. Ru, however, is a precious metal that has long term durability concerns. Ni/Ni oxide species offer a potential to replace Ru in MOR electrocatalysis. PtNiNWs were investigated for MOR and oxygen annealing was investigated as a route to improve catalyst performance (mass activitymore » 65% greater) and stability to potential cycling. Our results presented show that PtNiNWs offer significant promise in the area, but also result in Ni ion leaching that is a concern requiring further evaluation in fuel cells.« less

Novel application of simultaneous multi-image display during complex robotic abdominal procedures

PubMed Central

2014-01-01

Background The surgical robot offers the potential to integrate multiple views into the surgical console screen, and for the assistant’s monitors to provide real-time views of both fields of operation. This function has the potential to increase patient safety and surgical efficiency during an operation. Herein, we present a novel application of the multi-image display system for simultaneous visualization of endoscopic views during various complex robotic gastrointestinal operations. All operations were performed using the da Vinci Surgical System (Intuitive Surgical, Sunnyvale, CA, USA) with the assistance of Tilepro, multi-input display software, during employment of the intraoperative scopes. Three robotic operations, left hepatectomy with intraoperative common bile duct exploration, low anterior resection, and radical distal subtotal gastrectomy with intracorporeal gastrojejunostomy, were performed by three different surgeons at a tertiary academic medical center. Results The three complex robotic abdominal operations were successfully completed without difficulty or intraoperative complications. The use of the Tilepro to simultaneously visualize the images from the colonoscope, gastroscope, and choledochoscope made it possible to perform additional intraoperative endoscopic procedures without extra monitors or interference with the operations. Conclusion We present a novel use of the multi-input display program on the da Vinci Surgical System to facilitate the performance of intraoperative endoscopies during complex robotic operations. Our study offers another potentially beneficial application of the robotic surgery platform toward integration and simplification of combining additional procedures with complex minimally invasive operations. PMID:24628761

Laboratory microwave measurement of the moisture content in seed cotton and ginned cotton fiber

USDA-ARS?s Scientific Manuscript database

The timely and accurate measurement of cotton fiber moisture content is important, but the measurement is often performed by laborious, time-consuming laboratory oven drying methods. Microwave technology for measuring fiber moisture content directly (not for drying only) offers potential advantages...

Modeling and Evaluating Pilot Performance in NextGen: Review of and Recommendations Regarding Pilot Modeling Efforts, Architectures, and Validation Studies

NASA Technical Reports Server (NTRS)

Wickens, Christopher; Sebok, Angelia; Keller, John; Peters, Steve; Small, Ronald; Hutchins, Shaun; Algarin, Liana; Gore, Brian Francis; Hooey, Becky Lee; Foyle, David C.

2013-01-01

NextGen operations are associated with a variety of changes to the national airspace system (NAS) including changes to the allocation of roles and responsibilities among operators and automation, the use of new technologies and automation, additional information presented on the flight deck, and the entire concept of operations (ConOps). In the transition to NextGen airspace, aviation and air operations designers need to consider the implications of design or system changes on human performance and the potential for error. To ensure continued safety of the NAS, it will be necessary for researchers to evaluate design concepts and potential NextGen scenarios well before implementation. One approach for such evaluations is through human performance modeling. Human performance models (HPMs) provide effective tools for predicting and evaluating operator performance in systems. HPMs offer significant advantages over empirical, human-in-the-loop testing in that (1) they allow detailed analyses of systems that have not yet been built, (2) they offer great flexibility for extensive data collection, (3) they do not require experimental participants, and thus can offer cost and time savings. HPMs differ in their ability to predict performance and safety with NextGen procedures, equipment and ConOps. Models also vary in terms of how they approach human performance (e.g., some focus on cognitive processing, others focus on discrete tasks performed by a human, while others consider perceptual processes), and in terms of their associated validation efforts. The objectives of this research effort were to support the Federal Aviation Administration (FAA) in identifying HPMs that are appropriate for predicting pilot performance in NextGen operations, to provide guidance on how to evaluate the quality of different models, and to identify gaps in pilot performance modeling research, that could guide future research opportunities. This research effort is intended to help the FAA evaluate pilot modeling efforts and select the appropriate tools for future modeling efforts to predict pilot performance in NextGen operations.

Pulse Detonation Rocket Engine Research at NASA Marshall

NASA Technical Reports Server (NTRS)

Morris, Christopher I.

2003-01-01

Pulse detonation rocket engines (PDREs) offer potential performance improvements over conventional designs, but represent a challenging modeling task. A quasi 1-D, finite-rate chemistry CFD model for a PDRE is described and implemented. A parametric study of the effect of blowdown pressure ratio on the performance of an optimized, fixed PDRE nozzle configuration is reported. The results are compared to a steady-state rocket system using similar modeling assumptions.

Approach to Modeling Boundary Layer Ingestion Using a Fully Coupled Propulsion-RANS Model

NASA Technical Reports Server (NTRS)

Gray, Justin S.; Mader, Charles A.; Kenway, Gaetan K. W.; Martins, Joaquim R. R. A.

2017-01-01

Airframe-propulsion integration concepts that use boundary layer ingestion have the potential to reduce aircraft fuel burn. One concept that has been recently explored is NASA's Starc-ABL aircraft configuration, which offers the potential for 12% mission fuel burn reduction by using a turbo-electric propulsion system with an aft-mounted electrically driven boundary layer ingestion propulsor. This large potential for improved performance motivates a more detailed study of the boundary layer ingestion propulsor design, but to date, analyses of boundary layer ingestion have used uncoupled methods. These methods account for only aerodynamic effects on the propulsion system or propulsion system effects on the aerodynamics, but not both simultaneously. This work presents a new approach for building fully coupled propulsive-aerodynamic models of boundary layer ingestion propulsion systems. A 1D thermodynamic cycle analysis is coupled to a RANS simulation to model the Starc-ABL aft propulsor at a cruise condition and the effects variation in propulsor design on performance are examined. The results indicates that both propulsion and aerodynamic effects contribute equally toward the overall performance and that the fully coupled model yields substantially different results compared to uncoupled. The most significant finding is that boundary layer ingestion, while offering substantial fuel burn savings, introduces throttle dependent aerodynamics effects that need to be accounted for. This work represents a first step toward the multidisciplinary design optimization of boundary layer ingestion propulsion systems.

Performance evaluation of a center pivot variable rate irrigation system

USDA-ARS?s Scientific Manuscript database

Variable Rate Irrigation (VRI) for center pivots offers potential to match specific application rates to non-uniform soil conditions along the length of the lateral. The benefit of such systems is influenced by the areal extent of these variations and the smallest scale to which the irrigation syste...

Life Cycle Assessment as a Tool to Enhance the Environmental Performanceof Carbon Nanotube Products: A Review

EPA Science Inventory

The importance of evaluating the environmental performance of emerging carbon nanotube (CNT) products from a life cycle perspective is emphasized in this work. Design, development and deployment of CNT products offer many potential benefits to society, but not without negative im...

Describing Preservice Instrumental Music Educators' Pedagogical Content Knowledge

ERIC Educational Resources Information Center

Millican, J. Si

2016-01-01

In this descriptive study, I investigated the pedagogical content knowledge of 206 undergraduate music education students by presenting video recordings of beginning band students playing excerpts from their class method books. I asked these preservice educators to identify performance problems and offer potential solutions to the causes of those…

A review of nanostructured lithium ion battery materials via low temperature synthesis.

PubMed

Chen, Jiajun

2013-01-01

Nanostructured materials afford us new opportunities to improve the current technology for synthesizing Li ion batteries. Generating nanomaterials with new properties via an inexpensive approach offers a tremendous potential for realizing high performance Li-ion batteries. In this review, I mainly summarize some of the recent progress made, and describe the patents awarded on synthesizing nanostructured cathode materials for these batteries via low temperature wet- chemistry methods. From an economical view, such syntheses, especially hydrothermal synthesis, may offer the opportunities for significantly lowering the cost of manufacturing battery materials, while conferring distinct environmental advantages. Recent advances in in-situ (real time) X-ray diffraction for studying hydrothermal synthesis have great potential for bettering the rational design of advanced lithium-electrode materials. The development of this technique also will be discussed.

Reconfigurable Computing As an Enabling Technology for Single-Photon-Counting Laser Altimetry

NASA Technical Reports Server (NTRS)

Powell, Wesley; Hicks, Edward; Pinchinat, Maxime; Dabney, Philip; McGarry, Jan; Murray, Paul

2003-01-01

Single-photon-counting laser altimetry is a new measurement technique offering significant advantages in vertical resolution, reducing instrument size, mass, and power, and reducing laser complexity as compared to analog or threshold detection laser altimetry techniques. However, these improvements come at the cost of a dramatically increased requirement for onboard real-time data processing. Reconfigurable computing has been shown to offer considerable performance advantages in performing this processing. These advantages have been demonstrated on the Multi-KiloHertz Micro-Laser Altimeter (MMLA), an aircraft based single-photon-counting laser altimeter developed by NASA Goddard Space Flight Center with several potential spaceflight applications. This paper describes how reconfigurable computing technology was employed to perform MMLA data processing in real-time under realistic operating constraints, along with the results observed. This paper also expands on these prior results to identify concepts for using reconfigurable computing to enable spaceflight single-photon-counting laser altimeter instruments.

Solar-Powered Electric Propulsion Systems: Engineering and Applications

NASA Technical Reports Server (NTRS)

Stearns, J. W.; Kerrisk, D. J.

1966-01-01

Lightweight, multikilowatt solar power arrays in conjunction with electric propulsion offer potential improvements to space exploration, extending the usefulness of existing launch vehicles to higher-energy missions. Characteristics of solar-powered electric propulsion missions are outlined, and preliminary performance estimates are shown. Spacecraft system engineering is discussed with respect to parametric trade-offs in power and propulsion system design. Relationships between mission performance and propulsion system performance are illustrated. The present state of the art of electric propulsion systems is reviewed and related to the mission requirements identified earlier. The propulsion system design and test requirements for a mission spacecraft are identified and discussed. Although only ion engine systems are currently available, certain plasma propulsion systems offer some advantages in over-all system design. These are identified, and goals are set for plasma-thrustor systems to make them competitive with ion-engine systems for mission applications.

Learning potential and cognitive abilities in preschool boys with fragile X and Down syndrome.

PubMed

Valencia-Naranjo, Nieves; Robles-Bello, Mª Auxiliadora

2017-01-01

Enhancing cognitive abilities is relevant when devising treatment plans. This study examined the performance of preschool boys with Down syndrome and fragile X syndrome in cognitive tasks (e.g., nonverbal reasoning and short-term memory), as well as in improving cognitive functions by means of a learning potential methodology. The basic scales corresponding to the Skills and Learning Potential Preschool Scale were administered to children with Down syndrome and others with fragile X syndrome, matched for chronological age and nonverbal cognitive development level. The fragile X syndrome group showed stronger performance on short-term memory tasks than the Down syndrome group prior to intervention, with no differences recorded in nonverbal reasoning tasks. In addition, both groups' cognitive performance improved significantly between pre- and post-intervention. However, learning potential relative to auditory memory was limited in both groups, and for rule-based categorization in Down syndrome children. The scale offered the opportunity to assess young children's abilities and identify the degree of cognitive modifiability. Furthermore, factors that may potentially affect the children's performance before and during learning potential assessment are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Line Fluid Actuated Valve Development Program. [for application on the space shuttle

NASA Technical Reports Server (NTRS)

Lynch, R. A.

1975-01-01

The feasibility of a line-fluid actuated valve design for potential application as a propellant-control valve on the space shuttle was examined. Design and analysis studies of two prototype valve units were conducted and demonstrated performance is reported. It was shown that the line-fluid actuated valve concept offers distinct weight and electrical advantages over alternate valve concepts. Summaries of projected performance and design goals are also included.

A Taxonomy of Accountable Care Organizations for Policy and Practice

PubMed Central

Shortell, Stephen M; Wu, Frances M; Lewis, Valerie A; Colla, Carrie H; Fisher, Elliott S

2014-01-01

Objective To develop an exploratory taxonomy of Accountable Care Organizations (ACOs) to describe and understand early ACO development and to provide a basis for technical assistance and future evaluation of performance. Data Sources/Study Setting Data from the National Survey of Accountable Care Organizations, fielded between October 2012 and May 2013, of 173 Medicare, Medicaid, and commercial payer ACOs. Study Design Drawing on resource dependence and institutional theory, we develop measures of eight attributes of ACOs such as size, scope of services offered, and the use of performance accountability mechanisms. Data are analyzed using a two-step cluster analysis approach that accounts for both continuous and categorical data. Principal Findings We identified a reliable and internally valid three-cluster solution: larger, integrated systems that offer a broad scope of services and frequently include one or more postacute facilities; smaller, physician-led practices, centered in primary care, and that possess a relatively high degree of physician performance management; and moderately sized, joint hospital–physician and coalition-led groups that offer a moderately broad scope of services with some involvement of postacute facilities. Conclusions ACOs can be characterized into three distinct clusters. The taxonomy provides a framework for assessing performance, for targeting technical assistance, and for diagnosing potential antitrust violations. PMID:25251146

Silicon-Carbide Power MOSFET Performance in High Efficiency Boost Power Processing Unit for Extreme Environments

NASA Technical Reports Server (NTRS)

Ikpe, Stanley A.; Lauenstein, Jean-Marie; Carr, Gregory A.; Hunter, Don; Ludwig, Lawrence L.; Wood, William; Del Castillo, Linda Y.; Fitzpatrick, Fred; Chen, Yuan

2016-01-01

Silicon-Carbide device technology has generated much interest in recent years. With superior thermal performance, power ratings and potential switching frequencies over its Silicon counterpart, Silicon-Carbide offers a greater possibility for high powered switching applications in extreme environment. In particular, Silicon-Carbide Metal-Oxide- Semiconductor Field-Effect Transistors' (MOSFETs) maturing process technology has produced a plethora of commercially available power dense, low on-state resistance devices capable of switching at high frequencies. A novel hard-switched power processing unit (PPU) is implemented utilizing Silicon-Carbide power devices. Accelerated life data is captured and assessed in conjunction with a damage accumulation model of gate oxide and drain-source junction lifetime to evaluate potential system performance at high temperature environments.

A configuration development strategy for the NASP

NASA Astrophysics Data System (ADS)

Snyder, Curtis D.; Pinckney, S. Z.

Characteristics of airframe-integrated scramjet (AIS) aerospacecraft are studied using elementary and a recently developed AIS analysis code. Of principal interest is the definition of the AIS and what concepts offer the most potential. One of the concepts is selected for a limited optimization study aimed at defining the relationship of exhaust area to performance potential. The study shows that, if the AIS vehicle is to be fully constrained within the 'optimum' flowpath envelope, large values of exhaust-area-to-capture-area ratio are desired. A benefit of this choice is that performance at the very highest airbreather speeds is improved and, thus, may delay the need to switch to rocket power.

Cortical localization of cognitive function by regression of performance on event-related potentials

NASA Technical Reports Server (NTRS)

Montgomery, R. W.; Montgomery, L. D.; Guisado, R.

1992-01-01

This paper demonstrates a new method of mapping cortical localization of cognitive function, using electroencephalographic data. Cross-subject regression analyses are used to identify cortical sites and post-stimulus latencies where there is a high correlation between subjects' performance and their cognitive event-related potential amplitude. The procedure was tested using a mental arithmetic task and was found to identify essentially the same cortical regions that have been associated with such tasks on the basis of research with patients suffering localized cortical lesions. Thus, it appears to offer an inexpensive, noninvasive tool for exploring the dynamics of localization in neurologically normal subjects.

The Impact of Stereoscopic Imagery and Motion on Anatomical Structure Recognition and Visual Attention Performance

ERIC Educational Resources Information Center

Remmele, Martin; Schmidt, Elena; Lingenfelder, Melissa; Martens, Andreas

2018-01-01

Gross anatomy is located in a three-dimensional space. Visualizing aspects of structures in gross anatomy education should aim to provide information that best resembles their original spatial proportions. Stereoscopic three-dimensional imagery might offer possibilities to implement this aim, though some research has revealed potential impairments…

Leading Higher Education Professionals: Local, Connected, and Artful

ERIC Educational Resources Information Center

Bathurst, Ralph; van Gelderen, Marco

2014-01-01

In this paper, we explore the work life of a scholar new to academia in her methods of leading informally. We discuss five vignettes that offer moments of learning and reflection, including reducing performance anxiety, privileging financial accountability, the rise of the virtual world, the impact of silence, and the potential for confrontation…

Finite Element Analysis of Morphing Piezoelectric Structures Studied

NASA Technical Reports Server (NTRS)

Lee, Ho-Jun

2002-01-01

The development of morphing aerospace structures that optimize their shape offers the potential to significantly improve the performance of existing airplanes. These morphing vehicles will operate with new capabilities to reduce noise, damp vibrations, manipulate flow, and monitor damage. Piezoelectric materials represent one of the popular materials currently being investigated for applications in morphing structures.

Structural (Performance) class Potential for North America

Treesearch

Eric Jones; David E. Kretschmann; Kevin Cheung

2014-01-01

Structural class systems are species-independent product classification systems for structural timber. They are used throughout the world to reduce the number of species and grade choices that face the designer of wood construction projects. Structural class systems offer an opportunity to simplify timber specification in North America and to encourage more effective...

A Guide to Group Counseling in Junior High School. Futureprint Counseling Component.

ERIC Educational Resources Information Center

Guillen, Mary A.

Designed for junior high school counselors, the guide offers an outline for facilitating group counseling sessions. Intended to be held one class period a week for eight weeks, the sessions aim toward potential improvement in self-esteem, personal relationships, peer understanding, self-awareness, academic performance, and social skills. Each…

22 CFR 139.7 - Qualifications for participation as an employer in the United States.

Code of Federal Regulations, 2010 CFR

2010-04-01

.... employers must: (a) Provide job/training opportunities that: (1) Correspond to one of the occupational areas... assignment rotations, and/or training opportunities, which offer promotion potential if job performance is... same or similar work. (d) Agree not to petition for a change of immigration status or non-immigrant...

Using Keystroke Analytics to Improve Pass-Fail Classifiers

ERIC Educational Resources Information Center

Casey, Kevin

2017-01-01

Learning analytics offers insights into student behaviour and the potential to detect poor performers before they fail exams. If the activity is primarily online (for example computer programming), a wealth of low-level data can be made available that allows unprecedented accuracy in predicting which students will pass or fail. In this paper, we…

Marathon Groups. Facilitating the Personal Growth of Imprisoned, Black Female Heroin Abusers.

ERIC Educational Resources Information Center

Page, Richard C.; Kubiak, Larry

1978-01-01

Apparent success of the marathon groups in altering the perceptions of Black female heroin addicts toward the future, counseling, and themselves offers preliminary evidence that marathons may have potential as a counseling strategy with these clients. Future research needs to be performed to substantiate or reject these findings. (Author/PD)

Solar-pumped solid state Nd lasers

NASA Technical Reports Server (NTRS)

Williams, M. D.; Zapata, L.

1985-01-01

Solid state neodymium lasers are considered candidates for space-based polar-pumped laser for continuous power transmission. Laser performance for three different slab laser configurations has been computed to show the excellent power capability of such systems if heat problems can be solved. Ideas involving geometries and materials are offered as potential solutions to the heat problem.

Thermophotovoltaic power conversion systems: Current performance and future potential

DOE PAGES

Celanovic, Ivan; Bermel, Peter; Soljacic, Marin

2011-01-01

Thermophotovoltaic (TPV) systems offer a unique, solid-state approach to converting heat into electricity based on thermal radiation. TPV is particularly suitable for certain classes of power generation applications that are not well served by standard engines, such as long, remote missions where repairs are difficult, and portable generation where space and weight are at a premium. While standard thermophotovoltaics are limited in their conversion efficiency, photonic crystals can improve performance by an order of magnitude for a number of systems. While there are many potential applications, two exemplary systems are discussed: TPV μreactors for portable power generation in a mm-scalemore » form factor, and solar TPV for long-term off-grid power generation from sunlight. In both cases, photonic crystals can enable potential performance exceeding that of many other well-known technologies, such as single-junction photovoltaics.« less

Ethics, Nanobiosensors and Elite Sport: The Need for a New Governance Framework.

PubMed

Evans, Robert; McNamee, Michael; Guy, Owen

2017-12-01

Individual athletes, coaches and sports teams seek continuously for ways to improve performance and accomplishment in elite competition. New techniques of performance analysis are a crucial part of the drive for athletic perfection. This paper discusses the ethical importance of one aspect of the future potential of performance analysis in sport, combining the field of biomedicine, sports engineering and nanotechnology in the form of 'Nanobiosensors'. This innovative technology has the potential to revolutionise sport, enabling real time biological data to be collected from athletes that can be electronically distributed. Enabling precise real time performance analysis is not without ethical problems. Arguments concerning (1) data ownership and privacy; (2) data confidentiality; and (3) athlete welfare are presented alongside a discussion of the use of the Precautionary Principle in making ethical evaluations. We conclude, that although the future potential use of Nanobiosensors in sports analysis offers many potential benefits, there is also a fear that it could be abused at a sporting system level. Hence, it is essential for sporting bodies to consider the development of a robust ethically informed governance framework in advance of their proliferated use.

Shuttle/IUS performance for planetary missions. [Interim Upper Stage

NASA Technical Reports Server (NTRS)

Cork, M. J.; Driver, J. M.; Wright, J. L.

1975-01-01

Potential requirements for planetary missions in the 1980s, capabilities of the Interim Upper Stage (IUS) candidates to perform those missions, and Shuttle/IUS mission profile options for performance enhancement are examined. The most demanding planetary missions are the Pioneer Saturn/Uranus/Titan Probe and the Mariner-class orbiters of Mercury, Jupiter, and Saturn. Options available to designers of these missions will depend on the specific IUS selected for development and the programmatic phasing of the IUS and the NASA Tug. Use of Shuttle elliptic orbits as initial conditions for IUS ignition offers significant performance improvements; specific values are mission dependent.

Green Propulsion Advancement and Infusion

NASA Technical Reports Server (NTRS)

Mulkey, Henry W.; Maynard, Andrew P.; Anflo, Kjell

2018-01-01

All space missions benefit from increased propulsion system performance allowing lower spacecraft launch mass, larger scientific payloads, or extended on-orbit lifetimes. Likewise, propellant candidates that offer significant reduction in personnel hazards and shorter payload processing present a more attractive propulsion subsystem solution. Aiming to reduce risk to potential infusion missions and fully comprehend the alternative propellant performance, the work presented herein represents many years of development and collaborative efforts to successfully align higher performance, low toxicity hydrazine alternatives into NASA Goddard Space Flight Center (GSFC) missions. The High Performance Green Propulsion (HPGP) technology is being considered for Science Mission Directorate (SMD) missions.

Thermionic/AMTEC cascade converter concept for high-efficiency space power

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hagan, T.H. van; Smith, J.N. Jr.; Schuller, M.

1996-12-31

This paper presents trade studies that address the use of the thermionic/AMTEC cell--a cascaded, high-efficiency, static power conversion concept that appears well-suited to space power applications. Both the thermionic and AMTEC power conversion approaches have been shown to be promising candidates for space power. Thermionics offers system compactness via modest efficiency at high heat rejection temperatures, and AMTEC offers high efficiency at modest heat rejection temperature. From a thermal viewpoint the two are ideally suited for cascaded power conversion: thermionic heat rejection and AMTEC heat source temperatures are essentially the same. In addition to realizing conversion efficiencies potentially as highmore » as 35--40%, such a cascade offers the following perceived benefits: survivability; simplicity; technology readiness; and technology growth. Mechanical approaches and thermal/electric matching criteria for integrating thermionics and AMTEC into a single conversion device are described. Focusing primarily on solar thermal space power applications, parametric trends are presented to show the performance and cost potential that should be achievable with present-day technology in cascaded thermionic/AMTEC systems.« less

Flexible Fe3O4@Carbon Nanofibers Hierarchically Assembled with MnO2 Particles for High-Performance Supercapacitor Electrodes.

PubMed

Iqbal, Nousheen; Wang, Xianfeng; Babar, Aijaz Ahmed; Zainab, Ghazala; Yu, Jianyong; Ding, Bin

2017-11-09

Increasing use of wearable electronic devices have resulted in enhanced demand for highly flexible supercapacitor electrodes with superior electrochemical performance. In this study, flexible composite membranes with electrosprayed MnO 2 particles uniformly anchored on Fe 3 O 4 doped electrospun carbon nanofibers (Fe 3 O 4 @CNF Mn ) have been prepared as flexible electrodes for high-performance supercapacitors. The interconnected porous beaded structure ensures free movement of electrolyte within the composite membranes, therefore, the developed supercapacitor electrodes not only offer high specific capacitance of ~306 F/g, but also exhibit good capacitance retention of ~85% after 2000 cycles, which certify that the synthesized electrodes offer high and stable electrochemical performance. Additionally, the supercapacitors fabricated from our developed electrodes well maintain their performance under flexural stress and exhibit a very minute change in specific capacitance even up to 180° bending angle. The developed electrode fabrication strategy integrating electrospinning and electrospray techniques paves new insights into the development of potential functional nanofibrous materials for light weight and flexible wearable supercapacitors.

Aircrew Performance Cutting-Edge Tech: Emerging Human Performance Enhancement Technology Vision in Support of Operational Military Aviation Strategy

DTIC Science & Technology

2002-04-01

Origin and History, (RK, PRK , LASIK ) Refractive surgery was first considered as early as 1898 by a Dutch professor and was unsuccessfully attempted in...Keratomileusis ( LASIK ) LASIK offers the greatest potential for improving aviator vision and is the latest PRK -similar procedure. First, a flap of...showed that after LASIK , subjects did not exhibit a refractive shift of clinical significance.39 Therefore LASIK and PRK , recipients had no significant

Field testing of two prototype air-source integrated heat pumps for net zero energy home (nZEH) application

DOE PAGES

Baxter, Van D.; Munk, Jeffrey D.

2017-11-08

By integrating multiple functions into a single system it offers potential efficiency and cost reduction benefits. Oak Ridge National Laboratory (ORNL) and its partners have designed, developed, and tested two air-source heat pump designs that not only provide space heating and cooling, but also water heating, dehumidification, and ventilation functions. Some details on the design, simulated performance, prototype field test, measured performance, and lessons learned are provided.

Field testing of two prototype air-source integrated heat pumps for net zero energy home (nZEH) application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baxter, Van D.; Munk, Jeffrey D.

By integrating multiple functions into a single system it offers potential efficiency and cost reduction benefits. Oak Ridge National Laboratory (ORNL) and its partners have designed, developed, and tested two air-source heat pump designs that not only provide space heating and cooling, but also water heating, dehumidification, and ventilation functions. Some details on the design, simulated performance, prototype field test, measured performance, and lessons learned are provided.

Significant differences in pediatric psychotropic side effects: Implications for school performance.

PubMed

Kubiszyn, Thomas; Mire, Sarah; Dutt, Sonia; Papathopoulos, Katina; Burridge, Andrea Backsheider

2012-03-01

Some side effects (SEs) of increasingly prescribed psychotropic medications can impact student performance in school. SE risk varies, even among drugs from the same class (e.g., antidepressants). Knowing which SEs occur significantly more often than others may enable school psychologists to enhance collaborative risk-benefit analysis, medication monitoring, data-based decision-making, and inform mitigation efforts. SE data from Full Prescribing Information (PI) on the FDA website for ADHD drugs, atypical antipsychotics, and antidepressants with pediatric indications were analyzed. Risk ratios (RR) are reported for each drug within a category compared with placebo. RR tables and graphs inform the reader about SE incidence differences for each drug and provide clear evidence of the wide variability in SE incidence in the FDA data. Breslow-Day and Cochran Mantel-Haenszel methods were used to test for drug-placebo SE differences and to test for significance across drugs within each category based on odds ratios (ORs). Significant drug-placebo differences were found for each drug compared with placebo, when odds were pooled across all drugs in a category compared with placebo, and between some drugs within categories. Unexpectedly, many large RR differences did not reach significance. Potential explanations are offered, including limitations of the FDA data sets and statistical and methodological issues. Future research directions are offered. The potential impact of certain SEs on school performance, mitigation strategies, and the potential role of the school psychologist is discussed, with consideration for ethical and legal limitations. (c) 2012 APA, all rights reserved.

Optical interconnection networks for high-performance computing systems

NASA Astrophysics Data System (ADS)

Biberman, Aleksandr; Bergman, Keren

2012-04-01

Enabled by silicon photonic technology, optical interconnection networks have the potential to be a key disruptive technology in computing and communication industries. The enduring pursuit of performance gains in computing, combined with stringent power constraints, has fostered the ever-growing computational parallelism associated with chip multiprocessors, memory systems, high-performance computing systems and data centers. Sustaining these parallelism growths introduces unique challenges for on- and off-chip communications, shifting the focus toward novel and fundamentally different communication approaches. Chip-scale photonic interconnection networks, enabled by high-performance silicon photonic devices, offer unprecedented bandwidth scalability with reduced power consumption. We demonstrate that the silicon photonic platforms have already produced all the high-performance photonic devices required to realize these types of networks. Through extensive empirical characterization in much of our work, we demonstrate such feasibility of waveguides, modulators, switches and photodetectors. We also demonstrate systems that simultaneously combine many functionalities to achieve more complex building blocks. We propose novel silicon photonic devices, subsystems, network topologies and architectures to enable unprecedented performance of these photonic interconnection networks. Furthermore, the advantages of photonic interconnection networks extend far beyond the chip, offering advanced communication environments for memory systems, high-performance computing systems, and data centers.

Advanced Interval Management: A Benefit Analysis

NASA Technical Reports Server (NTRS)

Timer, Sebastian; Peters, Mark

2016-01-01

This document is the final report for the NASA Langley Research Center (LaRC)- sponsored task order 'Possible Benefits for Advanced Interval Management Operations.' Under this research project, Architecture Technology Corporation performed an analysis to determine the maximum potential benefit to be gained if specific Advanced Interval Management (AIM) operations were implemented in the National Airspace System (NAS). The motivation for this research is to guide NASA decision-making on which Interval Management (IM) applications offer the most potential benefit and warrant further research.

pH-responsive and enzymatically-responsive hydrogel microparticles for the oral delivery of therapeutic proteins: Effects of protein size, crosslinking density, and hydrogel degradation on protein delivery.

PubMed

Koetting, Michael Clinton; Guido, Joseph Frank; Gupta, Malvika; Zhang, Annie; Peppas, Nicholas A

2016-01-10

Two potential platform technologies for the oral delivery of protein therapeutics were synthesized and tested. pH-responsive poly(itaconic acid-co-N-vinyl-2-pyrrolidone) (P(IA-co-NVP)) hydrogel microparticles were tested in vitro with model proteins salmon calcitonin, urokinase, and rituximab to determine the effects of particle size, protein size, and crosslinking density on oral delivery capability. Particle size showed no significant effect on overall delivery potential but did improve percent release of encapsulated protein over the micro-scale particle size range studied. Protein size was shown to have a significant impact on the delivery capability of the P(IA-co-NVP) hydrogel. We show that when using P(IA-co-NVP) hydrogel microparticles with 3 mol% tetra(ethylene glycol) dimethacrylate crosslinker, a small polypeptide (salmon calcitonin) loads and releases up to 45 μg/mg hydrogel while the mid-sized protein urokinase and large monoclonal antibody rituximab load and release only 19 and 24 μg/mg hydrogel, respectively. We further demonstrate that crosslinking density offers a simple method for tuning hydrogel properties to variously sized proteins. Using 5 mol% TEGDMA crosslinker offers optimal performance for the small peptide, salmon calcitonin, whereas lower crosslinking density of 1 mol% offers optimal performance for the much larger protein rituximab. Finally, an enzymatically-degradable hydrogels of P(MAA-co-NVP) crosslinked with the peptide sequence MMRRRKK were synthesized and tested in simulated gastric and intestinal conditions. These hydrogels offer ideal loading and release behavior, showing no degradative release of encapsulated salmon calcitonin in gastric conditions while yielding rapid and complete release of encapsulated protein within 1h in intestinal conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

Conceptual design study of potential early commercial MHD powerplant. Report of task 2 results

NASA Astrophysics Data System (ADS)

Hals, F. A.

1981-03-01

The conceptual design of one of the potential early commercial MHD power plants was studied. The plant employs oxygen enrichment of the combustion air and preheating of this oxygen enriched air to an intermediate temperature of 1200 F attainable with a tubular type recuperative heat exchanger. Conceptual designs of plant componets and equipment with performance, operational characteristics, and costs are reported. Plant economics and overall performance including full and part load operation are reviewed. The projected performance and estimated cost of this early MHD plant are compared to conventional power plants, although it does not offer the same high efficiency and low costs as the mature MHD power plant. Environmental aspects and the methods incorporated in plant design for emission control of sulfur and nitrogen are reviewed.

Conceptual design study of potential early commercial MHD powerplant. Report of task 2 results

NASA Technical Reports Server (NTRS)

Hals, F. A.

1981-01-01

The conceptual design of one of the potential early commercial MHD power plants was studied. The plant employs oxygen enrichment of the combustion air and preheating of this oxygen enriched air to an intermediate temperature of 1200 F attainable with a tubular type recuperative heat exchanger. Conceptual designs of plant componets and equipment with performance, operational characteristics, and costs are reported. Plant economics and overall performance including full and part load operation are reviewed. The projected performance and estimated cost of this early MHD plant are compared to conventional power plants, although it does not offer the same high efficiency and low costs as the mature MHD power plant. Environmental aspects and the methods incorporated in plant design for emission control of sulfur and nitrogen are reviewed.

PSAT Component Scores as a Predictor of Success on AP Exam Performance for Diverse Students

ERIC Educational Resources Information Center

Richardson, Cristianne C.; Gonzalez, Alejandro; Leal, Lonnie; Castillo, Mary Z.; Carman, Carol A.

2016-01-01

While studies have shown the positive effect of the Advanced Placement (AP) program on college readiness, there are still barriers preventing minority and low socioeconomic status (SES) students who possess high academic potential from participating in the opportunity that AP courses offer. One tool that could help identify students for…

A Successful Test of Parallel Replication Teams in Teaching Research Methods

ERIC Educational Resources Information Center

Standing, Lionel G.; Astrologo, Lisa; Benbow, Felecia F.; Cyr-Gauthier, Chelsea S.; Williams, Charlotte A.

2016-01-01

This paper describes the novel use of parallel student teams from a research methods course to perform a replication study, and suggests that this approach offers pedagogical benefits for both students and teachers, as well as potentially contributing to a resolution of the replication crisis in psychology today. Four teams, of five undergraduates…

Titian: Data Provenance Support in Spark

PubMed Central

Interlandi, Matteo; Shah, Kshitij; Tetali, Sai Deep; Gulzar, Muhammad Ali; Yoo, Seunghyun; Kim, Miryung; Millstein, Todd; Condie, Tyson

2015-01-01

Debugging data processing logic in Data-Intensive Scalable Computing (DISC) systems is a difficult and time consuming effort. Today’s DISC systems offer very little tooling for debugging programs, and as a result programmers spend countless hours collecting evidence (e.g., from log files) and performing trial and error debugging. To aid this effort, we built Titian, a library that enables data provenance—tracking data through transformations—in Apache Spark. Data scientists using the Titian Spark extension will be able to quickly identify the input data at the root cause of a potential bug or outlier result. Titian is built directly into the Spark platform and offers data provenance support at interactive speeds—orders-of-magnitude faster than alternative solutions—while minimally impacting Spark job performance; observed overheads for capturing data lineage rarely exceed 30% above the baseline job execution time. PMID:26726305

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carter, E.

A new class of grout material based on molten wax offers a dramatic improvement in permeation grouting performance. This new material makes a perfect in situ containment of buried radioactive waste both feasible and cost effective. This paper describes various ways the material can be used to isolate buried waste in situ. Potential applications described in the paper include buried radioactive waste in deep trenches, deep shafts, Infiltration trenches, and large buried objects. Use of molten wax for retrieval of waste is also discussed. Wax can also be used for retrieval of air sensitive materials or drummed waste. This papermore » provides an analysis of the methods of application and the expected performance and cost of several potential projects. (authors)« less

Rewards and creative performance: a meta-analytic test of theoretically derived hypotheses.

PubMed

Byron, Kris; Khazanchi, Shalini

2012-07-01

Although many scholars and practitioners are interested in understanding how to motivate individuals to be more creative, whether and how rewards affect creativity remain unclear. We argue that the conflicting evidence may be due to differences between studies in terms of reward conditions and the context in which rewards are offered. Specifically, we examine 5 potential moderators of the rewards-creative performance relationship: (a) the reward contingency, (b) the extent to which participants are provided information about their past or current creative performance, (c) the extent to which the reward and context offer choice or impose control, (d) the extent to which the context serves to enhance task engagement, and (e) the extent to which the performance tasks are complex. Using random-effects models, we meta-analyzed 60 experimental and nonexperimental studies (including 69 independent samples) that examined the rewards-creativity relationship with children or adults. Our results suggest that creativity-contingent rewards tend to increase creative performance-and are more positively related to creative performance when individuals are given more positive, contingent, and task-focused performance feedback and are provided more choice (and are less controlled). In contrast, performance-contingent or completion-contingent rewards tend to have a slight negative effect on creative performance.

Potential of extended airbreathing operation of a two-stage launch vehicle by scramjet propulsion

NASA Astrophysics Data System (ADS)

Schoettle, U. M.; Hillesheimer, M.; Rahn, M.

This paper examines the application of scramjet propulsion to extend the ramjet operation of an airbreathing two-stage launch designed for horizontal takeoff and landing. Performance comparisons are made for two alternative propulsion concepts. The mission performance predictions presented are obtained from a multistep optimization procedure employing both trajectory optimization and vehicle design steps to achieve maximum payload capabilities. The simulation results are shown to offer an attractive payload advantage of the scramjet variant over the ramjet powered vehicle.

Tungsten fiber reinforced superalloys: A status review

NASA Technical Reports Server (NTRS)

Petrasek, D. W.; Signorelli, R. A.

1981-01-01

Improved performance of heat engines is largely dependent upon maximum cycle temperatures. Tungsten fiber reinforced superalloys (TFRS) are the first of a family of high temperature composites that offer the potential for significantly raising hot component operating temperatures and thus leading to improved heat engine performance. This status review of TFRS research emphasizes the promising property data developed to date, the status of TFRS composite airfoil fabrication technology, and the areas requiring more attention to assure their applicability to hot section components of aircraft gas turbine engines.

Fiber reinforced superalloys

NASA Technical Reports Server (NTRS)

Petrasek, Donald W.; Signorelli, Robert A.; Caulfield, Thomas; Tien, John K.

1987-01-01

Improved performance of heat engines is largely dependent upon maximum cycle temperatures. Tungsten fiber reinforced superalloys (TFRS) are the first of a family of high temperature composites that offer the potential for significantly raising hot component operating temperatures and thus leading to improved heat engine performance. This status review of TFRS research emphasizes the promising property data developed to date, the status of TFRS composite airfoil fabrication technology, and the areas requiring more attention to assure their applicability to hot section components of aircraft gas turbine engines.

Overcoming Present-Day Powerplant Limitations Via Unconventional Engine Configurations

NASA Technical Reports Server (NTRS)

Meitner, Peter L.

2006-01-01

The Army Research Laboratory s Vehicle Technology Directorate is sponsoring the prototype development of three unconventional engine concepts - two intermittent combustion (IC) engines and one turbine engine (via SBIR (Small Business Innovative Research) contracts). The IC concepts are the Nutating Engine and the Bonner Engine, and the turbine concept is the POWER Engine. Each of the three engines offers unique and greatly improved capabilities (which cannot be achieved by present-day powerplants), while offering significant reductions in size and weight. This paper presents brief descriptions of the physical characteristics of the three engines, and discusses their performance potentials, as well as their development status.

SOI technology for power management in automotive and industrial applications

NASA Astrophysics Data System (ADS)

Stork, Johannes M. C.; Hosey, George P.

2017-02-01

Semiconductor on Insulator (SOI) technology offers an assortment of opportunities for chip manufacturers in the Power Management market. Recent advances in the automotive and industrial markets, along with emerging features, the increasing use of sensors, and the ever-expanding "Internet of Things" (IoT) are providing for continued growth in these markets while also driving more complex solutions. The potential benefits of SOI include the ability to place both high-voltage and low-voltage devices on a single chip, saving space and cost, simplifying designs and models, and improving performance, thereby cutting development costs and improving time to market. SOI also offers novel new approaches to long-standing technologies.

Small capillary pumped AMTEC systems

NASA Astrophysics Data System (ADS)

Hunt, Thomas K.; Sievers, Robert K.; Butkiewicz, David A.; Pantolin, Jan E.; Ivanenok, Joseph F.

1993-01-01

Alkali Metal Thermoelectric Converter (AMTEC) systems offer significant potential advantages for space power. Recent experiments have shown that electromagnetic pumps can operate with a negative priming head and so may be suitable for space applications in microgravity (Hunt et al. 1992). Capillary pumped cells offer an alternative approach to microgravity compatibility. We have designed, built, and operated capillary pumped AMTEC cells in various orientations with respect to gravity in order to provide a presumptive demonstration of zero-G capability (Sievers et al. 1992). We report lifetime and performance data for these capillary pumped AMTEC cells. Progress on other issues relating to space flight testing of AMTEC systems is also discussed.

Chapter 28: Nanomaterials for Energy Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hurst, Katherine E; Luther, Joseph M; Ban, Chunmei

2017-01-02

A wide variety of nanomaterials have been applied to energy related applications, including nanofibers, nanocrystalline materials, nanoparticles, and thin film nanocoatings. Solid-state lighting offers significant advantages in energy efficiency compared to traditional lighting technologies. The potential for nanostructured solid-state lighting devices is excellent as it enjoys significant economic drivers in energy efficiency. Fuel cells convert chemical energy to electrical energy through electrochemical reactions at an anode and cathode. The conversion of biomass to fuels and chemicals offers great potential to reduce energy dependence on petroleum and reduce green house gas emissions. Batteries involve the production and storage of electrical charge,more » the transfer of cations and electrical current, each based on electrochemical reactions and chemical reactants. Battery performance relies on the complex processes and factors that affect the transport of charge in the reactants, and across the interface between the chemical phases.« less

Ionic Liquids as Electrolytes for Electrochemical Double-Layer Capacitors: Structures that Optimize Specific Energy.

PubMed

Mousavi, Maral P S; Wilson, Benjamin E; Kashefolgheta, Sadra; Anderson, Evan L; He, Siyao; Bühlmann, Philippe; Stein, Andreas

2016-02-10

Key parameters that influence the specific energy of electrochemical double-layer capacitors (EDLCs) are the double-layer capacitance and the operating potential of the cell. The operating potential of the cell is generally limited by the electrochemical window of the electrolyte solution, that is, the range of applied voltages within which the electrolyte or solvent is not reduced or oxidized. Ionic liquids are of interest as electrolytes for EDLCs because they offer relatively wide potential windows. Here, we provide a systematic study of the influence of the physical properties of ionic liquid electrolytes on the electrochemical stability and electrochemical performance (double-layer capacitance, specific energy) of EDLCs that employ a mesoporous carbon model electrode with uniform, highly interconnected mesopores (3DOm carbon). Several ionic liquids with structurally diverse anions (tetrafluoroborate, trifluoromethanesulfonate, trifluoromethanesulfonimide) and cations (imidazolium, ammonium, pyridinium, piperidinium, and pyrrolidinium) were investigated. We show that the cation size has a significant effect on the electrolyte viscosity and conductivity, as well as the capacitance of EDLCs. Imidazolium- and pyridinium-based ionic liquids provide the highest cell capacitance, and ammonium-based ionic liquids offer potential windows much larger than imidazolium and pyridinium ionic liquids. Increasing the chain length of the alkyl substituents in 1-alkyl-3-methylimidazolium trifluoromethanesulfonimide does not widen the potential window of the ionic liquid. We identified the ionic liquids that maximize the specific energies of EDLCs through the combined effects of their potential windows and the double-layer capacitance. The highest specific energies are obtained with ionic liquid electrolytes that possess moderate electrochemical stability, small ionic volumes, low viscosity, and hence high conductivity, the best performing ionic liquid tested being 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide.

Designing solution-processable air-stable liquid crystalline crosslinkable semiconductors.

PubMed

McCulloch, Iain; Bailey, Clare; Genevicius, Kristijonas; Heeney, Martin; Shkunov, Maxim; Sparrowe, David; Tierney, Steven; Zhang, Weimin; Baldwin, Rodney; Kreouzis, Theo; Andreasen, Jens W; Breiby, Dag W; Nielsen, Martin M

2006-10-15

Organic electronics technology, in which at least the semiconducting component of the integrated circuit is an organic material, offers the potential for fabrication of electronic products by low-cost printing technologies, such as ink jet, gravure offset lithography and flexography. The products will typically be of lower performance than those using the present state of the art single crystal or polysilicon transistors, but comparable to amorphous silicon. A range of prototypes are under development, including rollable electrophoretic displays, active matrix liquid crystal (LC) displays, flexible organic light emitting diode displays, low frequency radio frequency identification tag and other low performance electronics. Organic semiconductors that offer both electrical performance and stability with respect to storage and operation under ambient conditions are required. This work describes the development of reactive mesogen semiconductors, which form large crosslinked LC domains on polymerization within mesophases. These crosslinked domains offer mechanical stability and are inert to solvent exposure in further processing steps. Reactive mesogens containing conjugated aromatic cores, designed to facilitate charge transport and provide good oxidative stability, were prepared and their liquid crystalline properties evaluated. The organization and alignment of the mesogens, both before and after crosslinking, were probed by grazing incidence wide-angle X-ray scattering of thin films. Both time-of-flight and field effect transistor devices were prepared and their electrical characterization reported.

Silicon photonics for high-performance interconnection networks

NASA Astrophysics Data System (ADS)

Biberman, Aleksandr

2011-12-01

We assert in the course of this work that silicon photonics has the potential to be a key disruptive technology in computing and communication industries. The enduring pursuit of performance gains in computing, combined with stringent power constraints, has fostered the ever-growing computational parallelism associated with chip multiprocessors, memory systems, high-performance computing systems, and data centers. Sustaining these parallelism growths introduces unique challenges for on- and off-chip communications, shifting the focus toward novel and fundamentally different communication approaches. This work showcases that chip-scale photonic interconnection networks, enabled by high-performance silicon photonic devices, enable unprecedented bandwidth scalability with reduced power consumption. We demonstrate that the silicon photonic platforms have already produced all the high-performance photonic devices required to realize these types of networks. Through extensive empirical characterization in much of this work, we demonstrate such feasibility of waveguides, modulators, switches, and photodetectors. We also demonstrate systems that simultaneously combine many functionalities to achieve more complex building blocks. Furthermore, we leverage the unique properties of available silicon photonic materials to create novel silicon photonic devices, subsystems, network topologies, and architectures to enable unprecedented performance of these photonic interconnection networks and computing systems. We show that the advantages of photonic interconnection networks extend far beyond the chip, offering advanced communication environments for memory systems, high-performance computing systems, and data centers. Furthermore, we explore the immense potential of all-optical functionalities implemented using parametric processing in the silicon platform, demonstrating unique methods that have the ability to revolutionize computation and communication. Silicon photonics enables new sets of opportunities that we can leverage for performance gains, as well as new sets of challenges that we must solve. Leveraging its inherent compatibility with standard fabrication techniques of the semiconductor industry, combined with its capability of dense integration with advanced microelectronics, silicon photonics also offers a clear path toward commercialization through low-cost mass-volume production. Combining empirical validations of feasibility, demonstrations of massive performance gains in large-scale systems, and the potential for commercial penetration of silicon photonics, the impact of this work will become evident in the many decades that follow.

The Implementation of Advanced Solar Array Technology in Future NASA Missions

NASA Technical Reports Server (NTRS)

Piszczor, Michael F.; Kerslake, Thomas W.; Hoffman, David J.; White, Steve; Douglas, Mark; Spence, Brian; Jones, P. Alan

2003-01-01

Advanced solar array technology is expected to be critical in achieving the mission goals on many future NASA space flight programs. Current PV cell development programs offer significant potential and performance improvements. However, in order to achieve the performance improvements promised by these devices, new solar array structures must be designed and developed to accommodate these new PV cell technologies. This paper will address the use of advanced solar array technology in future NASA space missions and specifically look at how newer solar cell technologies impact solar array designs and overall power system performance.

Inflatable Re-Entry Vehicle Experiment (IRVE) Design Overview

NASA Technical Reports Server (NTRS)

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

2005-01-01

Inflatable aeroshells offer several advantages over traditional rigid aeroshells for atmospheric entry. Inflatables offer increased payload volume fraction of the launch vehicle shroud and the possibility to deliver more payload mass to the surface for equivalent trajectory constraints. An inflatable s diameter is not constrained by the launch vehicle shroud. The resultant larger drag area can provide deceleration equivalent to a rigid system at higher atmospheric altitudes, thus offering access to higher landing sites. When stowed for launch and cruise, inflatable aeroshells allow access to the payload after the vehicle is integrated for launch and offer direct access to vehicle structure for structural attachment with the launch vehicle. They also offer an opportunity to eliminate system duplication between the cruise stage and entry vehicle. There are however several potential technical challenges for inflatable aeroshells. First and foremost is the fact that they are flexible structures. That flexibility could lead to unpredictable drag performance or an aerostructural dynamic instability. In addition, durability of large inflatable structures may limit their application. They are susceptible to puncture, a potentially catastrophic insult, from many possible sources. Finally, aerothermal heating during planetary entry poses a significant challenge to a thin membrane. NASA Langley Research Center and NASA's Wallops Flight Facility are jointly developing inflatable aeroshell technology for use on future NASA missions. The technology will be demonstrated in the Inflatable Re-entry Vehicle Experiment (IRVE). This paper will detail the development of the initial IRVE inflatable system to be launched on a Terrier/Orion sounding rocket in the fourth quarter of CY2005. The experiment will demonstrate achievable packaging efficiency of the inflatable aeroshell for launch, inflation, leak performance of the inflatable system throughout the flight regime, structural integrity when exposed to a relevant dynamic pressure and aerodynamic stability of the inflatable system. Structural integrity and structural response of the inflatable will be verified with photogrammetric measurements of the back side of the aeroshell in flight. Aerodynamic stability as well as drag performance will be verified with on board inertial measurements and radar tracking from multiple ground radar stations. The experiment will yield valuable information about zero-g vacuum deployment dynamics of the flexible inflatable structure with both inertial and photographic measurements. In addition to demonstrating inflatable technology, IRVE will validate structural, aerothermal, and trajectory modeling techniques for the inflatable. Structural response determined from photogrammetrics will validate structural models, skin temperature measurements and additional in-depth temperature measurements will validate material thermal performance models, and on board inertial measurements along with radar tracking from multiple ground radar stations will validate trajectory simulation models.

Preventing a Relapse or Setting Goals? Elucidating the Impact of Post-Training Transfer Interventions on Training Transfer Performance

ERIC Educational Resources Information Center

Rahyuda, Agoes Ganesha; Soltani, Ebrahim; Syed, Jawad

2018-01-01

Based on a review of the literature on post-training transfer interventions, this paper offers a conceptual model that elucidates potential mechanisms through which two types of post-training transfer intervention (relapse prevention and proximal plus distal goal setting) influence the transfer of training. We explain how the application of…

The Barefoot Hours: Out-of-School Programs Offer To Make the Most of Kids' Free Time, Turning Potentially Risky Afternoons into Golden Hours of Opportunity.

ERIC Educational Resources Information Center

Boss, Suzie

2002-01-01

Research suggests that after-school programs reduce juvenile crime and risky behavior; increase confidence, academic performance, and social skills; and build positive adult-child and home-school relationships. The need for supervised after-school activities, especially in poor neighborhoods; the characteristics of successful programs; and the…

A large array of high-performance artificial stars using airship-supported small mirrors

NASA Astrophysics Data System (ADS)

Content, Robert; Foxwell, Mark; Murray, Graham J.

2004-10-01

We propose a practical system that can provide a large number of high performance artificial stars, of the order of a few hundred, using an array of small mirrors on an airship supported platform illuminated from the ground by a laser. Our concept offers several advantages over other guide star schemes: Airborne mirror arrays can furnish tip-tilt information; they also permit a considerable reduction in the total ground-laser power required; high intensity guide stars with very small angular image size are possible; and finally they offer very low scattered parasite laser light. More basic & simpler launch-laser & AO technologies can therefore be employed, with potentially huge cost savings, with potentially significant improvement in the quality of the AO correction. The general platform scheme and suitable lift technologies are also discussed. A novel concept for achieving precise positioning is presented whereby the platform & the lifting vehicle are linked by a tether, the platform having a degree of independent control. Our proposal would employ as the lift vehicle an autonomous high altitude airship of the type currently under widespread development in the commercial sector, for use as hubs for telecommunication networks, mobile telephone relay stations, etc.

CVD Rhenium Engines for Solar-Thermal Propulsion Systems

NASA Technical Reports Server (NTRS)

Williams, Brian E.; Fortini, Arthur J.; Tuffias, Robert H.; Duffy, Andrew J.; Tucker, Stephen P.

1999-01-01

Solar-thermal upper-stage propulsion systems have the potential to provide specific impulse approaching 900 seconds, with 760 seconds already demonstrated in ground testing. Such performance levels offer a 100% increase in payload capability compared to state-of-the-art chemical upper-stage systems, at lower cost. Although alternatives such as electric propulsion offer even greater performance, the 6- to 18- month orbital transfer time is a far greater deviation from the state of the art than the one to two months required for solar propulsion. Rhenium metal is the only material that is capable of withstanding the predicted thermal, mechanical, and chemical environment of a solar-thermal propulsion device. Chemical vapor deposition (CVD) is the most well-established and cost-effective process for the fabrication of complex rhenium structures. CVD rhenium engines have been successfully constructed for the Air Force ISUS program (bimodal thrust/electricity) and the NASA Shooting Star program (thrust only), as well as under an Air Force SBIR project (thrust only). The bimodal engine represents a more long-term and versatile approach to solar-thermal propulsion, while the thrust-only engines provide a potentially lower weight/lower cost and more near-term replacement for current upper-stage propulsion systems.

Simplified Analysis of Pulse Detonation Rocket Engine Blowdown Gasdynamics and Performance

NASA Technical Reports Server (NTRS)

Morris, C. I.; Rodgers, Stephen L. (Technical Monitor)

2002-01-01

Pulse detonation rocket engines (PDREs) offer potential performance improvements over conventional designs, but represent a challenging modellng task. A simplified model for an idealized, straight-tube, single-shot PDRE blowdown process and thrust determination is described and implemented. In order to form an assessment of the accuracy of the model, the flowfield time history is compared to experimental data from Stanford University. Parametric Studies of the effect of mixture stoichiometry, initial fill temperature, and blowdown pressure ratio on the performance of a PDRE are performed using the model. PDRE performance is also compared with a conventional steady-state rocket engine over a range of pressure ratios using similar gasdynamic assumptions.

Preliminary Investigation of an Active PLZT Lens

NASA Technical Reports Server (NTRS)

Lightsey, W. D.; Peters, B. R.; Reardon, P. J.; Wong, J. K.

2001-01-01

The design, analysis and preliminary testing of a prototype Adjustable Focus Optical Correction Lens (AFOCL) is described. The AFOCL is an active optical component composed of solid state lead lanthanum-modified zirconate titanate (PLZT) ferroelectric ceramic with patterned indium tin oxide (ITO) transparent surface electrodes that modulate the refractive index of the PLZT to function as an electro-optic lens. The AFOCL was developed to perform optical re-alignment and wavefront correction to enhance the performance of Ultra-Lightweight Structures and Space Observatories (ULSSO). The AFOCL has potential application as an active optical component within a larger optical system. As such, information from a wavefront sensor would be processed to provide input to the AFOCL to drive the sensed wavefront to the desired shape and location. While offering variable and rapid focussing capability (controlled wavefront manipulation) similar to liquid crystal based spatial light modulators (SLM), the AFOCL offers some potential advantages because it is a solid-state, stationary, low-mass, rugged, and thin optical element that can produce wavefront quality comparable to the solid refractive lens it replaces. The AFOCL acts as a positive or negative lens by producing a parabolic phase-shift in the PLZT material through the application of a controlled voltage potential across the ITO electrodes. To demonstrate the technology, a 4 mm diameter lens was fabricated to produce 5-waves of optical power operating at 2.051 micrometer wavelength. Optical metrology was performed on the device to measure focal length, optical quality, and efficiency for a variety of test configurations. The data was analyzed and compared to theoretical data available from computer-based models of the AFOCL.

Rewarding healthy behaviors--pay patients for performance.

PubMed

Wu, Joanne

2012-01-01

Despite a considerable investment of resources into pay for performance, preliminary studies have found that it may not be significantly more effective in improving health outcome measures when compared with voluntary quality improvement programs. Because patient behaviors ultimately affect health outcomes, I would propose a novel pay-for-performance program that rewards patients directly for achieving evidence-based health goals. These rewards would be in the form of discounts towards co-payments for doctor's visits, procedures, and medications, thereby potentially reducing cost and compliance issues. A pilot study recruiting patients with diabetes or hypertension, diseases with clear and objective outcome measures, would be useful to examine true costs, savings, and health outcomes of such a reward program. Offering incentives to patients for reaching health goals has the potential to foster a stronger partnership between doctors and patients and improve health outcomes.

Information, support, and follow-up offered to women who experienced severe maternal morbidity.

PubMed

Furniss, Mary; Conroy, Molly; Filoche, Sara; MacDonald, E Jane; Geller, Stacie E; Lawton, Beverley

2018-06-01

To determine what information, support, and follow-up were offered to women who had experienced severe maternal morbidity (SMM). The present retrospective case review included patients who experienced SMM (admission to intensive care during pregnancy or up to 42 days postpartum) who had previously been reviewed for potential preventability as part of a nationwide New Zealand study performed between January 1 and December 31, 2014. Data were audited to ascertain documented evidence of an event debrief or explanation; referral to social support and/or mental health services; a detailed discharge letter; and a follow-up appointment with a specialist. Of 257 patients who experienced SMM, 23 (8.9%) were offered all four components of care, 99 (38.5%) an event debrief, 102 (39.7%) a referral to social support and/or mental health services, 148 (57.6%) a detailed discharge letter, and 131 (51.0%) a follow-up appointment. Many women who had experienced SMM did not receive explanatory information about their illness, an offer of psychosocial support, or a follow-up appointment prior to discharge from hospital. It is incumbent on clinicians and the maternity care system to improve these aspects of care for all women experiencing a potentially life-changing SMM event to minimize the risk and burden of long-term mental illness. © 2018 International Federation of Gynecology and Obstetrics.

Surgical simulation: a urological perspective.

PubMed

Wignall, Geoffrey R; Denstedt, John D; Preminger, Glenn M; Cadeddu, Jeffrey A; Pearle, Margaret S; Sweet, Robert M; McDougall, Elspeth M

2008-05-01

Surgical education is changing rapidly as several factors including budget constraints and medicolegal concerns limit opportunities for urological trainees. New methods of skills training such as low fidelity bench trainers and virtual reality simulators offer new avenues for surgical education. In addition, surgical simulation has the potential to allow practicing surgeons to develop new skills and maintain those they already possess. We provide a review of the background, current status and future directions of surgical simulators as they pertain to urology. We performed a literature review and an overview of surgical simulation in urology. Surgical simulators are in various stages of development and validation. Several simulators have undergone extensive validation studies and are in use in surgical curricula. While virtual reality simulators offer the potential to more closely mimic reality and present entire operations, low fidelity simulators remain useful in skills training, particularly for novices and junior trainees. Surgical simulation remains in its infancy. However, the potential to shorten learning curves for difficult techniques and practice surgery without risk to patients continues to drive the development of increasingly more advanced and realistic models. Surgical simulation is an exciting area of surgical education. The future is bright as advancements in computing and graphical capabilities offer new innovations in simulator technology. Simulators must continue to undergo rigorous validation studies to ensure that time spent by trainees on bench trainers and virtual reality simulators will translate into improved surgical skills in the operating room.

Lifetime testing UV LEDs for use in the LISA charge management system

NASA Astrophysics Data System (ADS)

Hollington, D.; Baird, J. T.; Sumner, T. J.; Wass, P. J.

2017-10-01

As a future charge management light source, UV light-emitting diodes (UV LEDs) offer far superior performance in a range of metrics compared to the mercury lamps used in the past. As part of a qualification program a number of short wavelength UV LEDs have been subjected to a series of lifetime tests for potential use on the laser interferometer space antenna (LISA) mission. These tests were performed at realistic output levels for both fast and continuous discharging in either a DC or pulsed mode of operation and included a DC fast discharge test spanning 50 days, a temperature dependent pulsed fast discharge test spanning 21 days and a pulsed continuous discharge test spanning 507 days. Two types of UV LED have demonstrated lifetimes equivalent to over 25 years of realistic mission usage with one type providing a baseline for LISA and the other offering a backup solution.

Autologous islet transplantation: challenges and lessons.

PubMed

Dunn, Ty B; Wilhelm, Joshua J; Bellin, Melena D; Pruett, Timothy L

2017-08-01

Human islet isolation and autotransplantation [autologous islet transplant (AUTX)] is performed to prevent or ameliorate brittle diabetes after total pancreatectomy performed for benign disease. The success or failure of the transplant can be associated with a profound impact on the individual's quality of life and even survival. AUTX offers unique insights into the effects of pancreas quality, islet number, isolation technique and alternate site engraftment on transplant efficacy. Herein, we review islet isolation with a focus on potential pathways to further optimize the endocrine outcome of AUTX, and compare and contrast differences in islet processing for AUTX and allotransplantation (allogeneic islet transplant). New knowledge of human islet biology and issues surrounding the engraftment process offer opportunities for innovative approaches toward optimizing islet cell transplantation. Improving the rate and durability of insulin independence in the often-times marginal dose model of AUTX may provide new insight toward improving the efficiency and durability of single donor islet (allogeneic islet transplant).

Research Performance Progress Report: Diverging Supernova Explosion Experiments on NIF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plewa, Tomasz

2016-10-25

The aim of this project was to design a series of blast-wave driven Rayleigh-Taylor (RT) experiments on the National Ignition Facility (NIF). The experiments of this kind are relevant to mixing in core-collapse supernovae (ccSNe) and have the potential to address previously unanswered questions in high-energy density physics (HEDP) and astrophysics. The unmatched laser power of the NIF laser offers a unique chance to observe and study “new physics” like the mass extensions observed in HEDP RT experiments performed on the Omega laser [1], which might be linked to self-generated magnetic fields [2] and so far could not be reproducedmore » by numerical simulations. Moreover, NIF is currently the only facility that offers the possibility to execute a diverging RT experiment, which would allow to observe processes such as inter-shell penetration via turbulent mixing and shock-proximity effects (distortion of the shock by RT spikes).« less

A Review of Zoonotic Infection Risks Associated with the Wild Meat Trade in Malaysia.

PubMed

Cantlay, Jennifer Caroline; Ingram, Daniel J; Meredith, Anna L

2017-06-01

The overhunting of wildlife for food and commercial gain presents a major threat to biodiversity in tropical forests and poses health risks to humans from contact with wild animals. Using a recent survey of wildlife offered at wild meat markets in Malaysia as a basis, we review the literature to determine the potential zoonotic infection risks from hunting, butchering and consuming the species offered. We also determine which taxa potentially host the highest number of pathogens and discuss the significant disease risks from traded wildlife, considering how cultural practices influence zoonotic transmission. We identify 51 zoonotic pathogens (16 viruses, 19 bacteria and 16 parasites) potentially hosted by wildlife and describe the human health risks. The Suidae and the Cervidae families potentially host the highest number of pathogens. We conclude that there are substantial gaps in our knowledge of zoonotic pathogens and recommend performing microbial food safety risk assessments to assess the hazards of wild meat consumption. Overall, there may be considerable zoonotic risks to people involved in the hunting, butchering or consumption of wild meat in Southeast Asia, and these should be considered in public health strategies.

FEL for the polymer processing industries

NASA Astrophysics Data System (ADS)

Kelley, Michael J.

1997-05-01

Polymers are everywhere in modern life because of their unique combination of end-use functionalities, ease of processing, recycling potential and modest cost. The physical and economic scope of the infrastructure committed to present polymers makes the introduction of entirely new chemistry unlikely. Rather, the breadth of commercial offerings more likely to shrink in the face of the widening mandate for recycling, especially of packaging. Improved performance and new functionality must therefore come by routes such as surface modification. However they must come with little environmental impact and at painfully low cost. Processing with strongly absorbed light offers unique advantages. The journal and patent literatures disclose a number of examples of benefits that can be achieved, principally by use of excimer lasers or special UV lamps. Examples of commercialization are few, however, because of the unit cost and maximum scale of existing light sources. A FEL, however, offers unique advantages: tunability to the optimum wavelength, potential for scale up to high average power, and a path to attractively low unit cost of light. A business analysis of prospective applications defines the technical and economic requirements a FEL for polymer surface processing must meet. These are compared to FEL technology as it now stands and as it is envisioned.

Screening studies of advanced control concepts for airbreathing engines

NASA Technical Reports Server (NTRS)

Ouzts, Peter J.; Lorenzo, Carl F.; Merrill, Walter C.

1993-01-01

The application of advanced control concepts to airbreathing engines may yield significant improvements in aircraft/engine performance and operability. Accordingly, the NASA Lewis Research Center has conducted screening studies of advanced control concepts for airbreathing engines to determine their potential impact on turbine engine performance and operability. The purpose of the studies was to identify concepts which offered high potential yet may incur high research and development risk. A target suite of proposed concepts was formulated by NASA and industry. These concepts were evaluated in a two phase study to quantify each concept's impact on desired engine characteristics. To aid in the evaluation, three target aircraft/engine combinations were considered: a military high performance fighter mission, a high speed civil transport mission, and a civil tiltrotor mission. Each of the advanced control concepts considered in the study were defined and described. The concept's potential impact on engine performance was determined. Relevant figures of merit on which to evaluate the concepts were also determined. Finally, the concepts were ranked with respect to the target aircraft/engine missions.

Metal Additive Manufacturing: A Review

NASA Astrophysics Data System (ADS)

Frazier, William E.

2014-06-01

This paper reviews the state-of-the-art of an important, rapidly emerging, manufacturing technology that is alternatively called additive manufacturing (AM), direct digital manufacturing, free form fabrication, or 3D printing, etc. A broad contextual overview of metallic AM is provided. AM has the potential to revolutionize the global parts manufacturing and logistics landscape. It enables distributed manufacturing and the productions of parts-on-demand while offering the potential to reduce cost, energy consumption, and carbon footprint. This paper explores the material science, processes, and business consideration associated with achieving these performance gains. It is concluded that a paradigm shift is required in order to fully exploit AM potential.

Qualification and Testing of Quantum Cascade Lasers for Harsh Environments

NASA Astrophysics Data System (ADS)

Brauer, C. S.; Myers, T. L.; Cannon, B. D.; Anderson, C. G.; Crowther, B. G.; Hansen, S.

2014-12-01

Quantum cascade lasers (QCLs) offer the potential for the development of novel, laser-based instruments for both terrestrial and space applications. In order to withstand harsh conditions encountered in these environments, lasers must be robust, and rigorous testing is required before new systems can be utilized. A particular concern for space applications is the potential damage to laser performance caused by radiation exposure. While the effects of radiation exposure in diode lasers have been studied extensively, the effect on QCLs, which are fundamentally different from diode lasers, is not well known. We thus present work to quantify the performance of QCLs after exposure to moderate and high levels of radiation from different sources, including protons and gamma rays, to determine the effects of radiation damage.

Green Propulsion Advancement and Infusion

NASA Technical Reports Server (NTRS)

Mulkey, Henry W.; Maynard, Andrew P.; Anflo, Kjell

2018-01-01

All space missions benefit from increased propulsion system performance, allowing lower spacecraft launch mass, larger scientific payloads, or extended on-orbit lifetimes. Likewise, long-term storable liquid propellant candidates that offer significant reduction in personnel hazards and shorter payload processing schedules present a more attractive propulsion subsystem solution to spacecraft builders. Aiming to reduce risk to potential infusion missions and fully comprehend the alternative propellant performance, the work presented herein represents many years of development and collaborative efforts to successfully align higher performance, low toxicity green propellants into NASA Goddard Space Flight Center (GSFC) missions. High Performance Green Propulsion (HPGP), and the associated propellant technology, has advanced significantly in maturity with increased familiarity with LMP-103S propellant handling, the proven reduction in loading hazards, successful launches conducted at multiple international Ranges, and HPGP on-orbit flight heritage. As science missions move forward to the potential infusion of HPGP technology, the National Aeronautics and Space Administration (NASA) and its partners are working to address gaps in system performance and operational considerations.

Agent-based modeling as a tool for program design and evaluation.

PubMed

Lawlor, Jennifer A; McGirr, Sara

2017-12-01

Recently, systems thinking and systems science approaches have gained popularity in the field of evaluation; however, there has been relatively little exploration of how evaluators could use quantitative tools to assist in the implementation of systems approaches therein. The purpose of this paper is to explore potential uses of one such quantitative tool, agent-based modeling, in evaluation practice. To this end, we define agent-based modeling and offer potential uses for it in typical evaluation activities, including: engaging stakeholders, selecting an intervention, modeling program theory, setting performance targets, and interpreting evaluation results. We provide demonstrative examples from published agent-based modeling efforts both inside and outside the field of evaluation for each of the evaluative activities discussed. We further describe potential pitfalls of this tool and offer cautions for evaluators who may chose to implement it in their practice. Finally, the article concludes with a discussion of the future of agent-based modeling in evaluation practice and a call for more formal exploration of this tool as well as other approaches to simulation modeling in the field. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fuel-optimal, low-thrust transfers between libration point orbits

NASA Astrophysics Data System (ADS)

Stuart, Jeffrey R.

Mission design requires the efficient management of spacecraft fuel to reduce mission cost, increase payload mass, and extend mission life. High efficiency, low-thrust propulsion devices potentially offer significant propellant reductions. Periodic orbits that exist in a multi-body regime and low-thrust transfers between these orbits can be applied in many potential mission scenarios, including scientific observation and communications missions as well as cargo transport. In light of the recent discovery of water ice in lunar craters, libration point orbits that support human missions within the Earth-Moon region are of particular interest. This investigation considers orbit transfer trajectories generated by a variable specific impulse, low-thrust engine with a primer-vector-based, fuel-optimizing transfer strategy. A multiple shooting procedure with analytical gradients yields rapid solutions and serves as the basis for an investigation into the trade space between flight time and consumption of fuel mass. Path and performance constraints can be included at node points along any thrust arc. Integration of invariant manifolds into the design strategy may also yield improved performance and greater fuel savings. The resultant transfers offer insight into the performance of the variable specific impulse engine and suggest novel implementations of conventional impulsive thrusters. Transfers incorporating invariant manifolds demonstrate the fuel savings and expand the mission design capabilities that are gained by exploiting system symmetry. A number of design applications are generated.

Comparative measurements of plasma potential with ball-pen and Langmuir probe in low-temperature magnetized plasma

NASA Astrophysics Data System (ADS)

Zanáška, M.; Adámek, J.; Peterka, M.; Kudrna, P.; Tichý, M.

2015-03-01

The ball-pen probe (BPP) is used for direct plasma potential measurements in magnetized plasma. The probe can adjust the ratio of the electron and ion saturation currents Isat-/Isat+ to be close to one and therefore its I-V characteristic becomes nearly symmetric. If this is achieved, the floating potential of the BPP is close to the plasma potential. Because of its rather simple construction, it offers an attractive probe for measurements in magnetized plasma. Comparative measurements of plasma potential by BPPs of different dimensions as well as one Langmuir probe (LP) in an argon discharge plasma of a cylindrical magnetron were performed at various experimental conditions. An additional comparison by an emissive probe was also performed. All these types of probes provide similar values of plasma potential in a wide range of plasma parameters. Our results for three different BPP dimensions indicate that the BPP can be operated in a cylindrical magnetron DC argon discharge if the value of the ratio of the magnetic field and neutral gas pressure, B/p, is greater than approximately 10 mT/Pa.

Injection Locking Techniques for Spectrum Analysis

NASA Astrophysics Data System (ADS)

Gathma, Timothy D.; Buckwalter, James F.

2011-04-01

Wideband spectrum analysis supports future communication systems that reconfigure and adapt to the capacity of the spectral environment. While test equipment manufacturers offer wideband spectrum analyzers with excellent sensitivity and resolution, these spectrum analyzers typically cannot offer acceptable size, weight, and power (SWAP). CMOS integrated circuits offer the potential to fully integrate spectrum analysis capability with analog front-end circuitry and digital signal processing on a single chip. Unfortunately, CMOS lacks high-Q passives and wideband resonator tunability that is necessary for heterodyne implementations of spectrum analyzers. As an alternative to the heterodyne receiver architectures, two nonlinear methods for performing wideband, low-power spectrum analysis are presented. The first method involves injecting the spectrum of interest into an array of injection-locked oscillators. The second method employs the closed loop dynamics of both injection locking and phase locking to independently estimate the injected frequency and power.

REUSABLE PROPULSION ARCHITECTURE FOR SUSTAINABLE LOW-COST ACCESS TO SPACE

NASA Technical Reports Server (NTRS)

Bonometti, J. A.; Dankanich, J. W.; Frame, K. L.

2005-01-01

The primary obstacle to any space-based mission is, and has always been, the cost of access to space. Even with impressive efforts toward reusability, no system has come close to lowering the cost a significant amount. It is postulated here, that architectural innovation is necessary to make reusability feasible, not incremental subsystem changes. This paper shows two architectural approaches of reusability that merit further study investments. Both #inherently# have performance increases and cost advantages to make affordable access to space a near term reality. A rocket launched from a subsonic aircraft (specifically the Crossbow methodology) and a momentum exchange tether, reboosted by electrodynamics, offer possibilities of substantial reductions in the total transportation architecture mass - making access-to-space cost-effective. They also offer intangible benefits that reduce risk or offer large growth potential. The cost analysis indicates that approximately a 50% savings is obtained using today#s aerospace materials and practices.

Advanced controls for airbreathing engines, volume 3: Allison gas turbine

NASA Technical Reports Server (NTRS)

Bough, R. M.

1993-01-01

The application of advanced control concepts to airbreathing engines may yield significant improvements in aircraft/engine performance and operability. Screening studies of advanced control concepts for airbreathing engines were conducted by three major domestic aircraft engine manufacturers to determine the potential impact of concepts on turbine engine performance and operability. The purpose of the studies was to identify concepts which offered high potential yet may incur high research and development risk. A target suite of proposed advanced control concepts was formulated and evaluated in a two-phase study to quantify each concept's impact on desired engine characteristics. To aid in the evaluation specific aircraft/engine combinations were considered: a Military High Performance Fighter mission, a High Speed Civil Transport mission, and a Civil Tiltrotor mission. Each of the advanced control concepts considered in the study are defined and described. The concept potential impact on engine performance was determined. Relevant figures of merit on which to evaluate the concepts are determined. Finally, the concepts are ranked with respect to the target aircraft/engine missions. A final report describing the screening studies was prepared by each engine manufacturer. Volume 3 of these reports describes the studies performed by the Allison Gas Turbine Division.

Advanced control for airbreathing engines, volume 1: Pratt and Whitney

NASA Technical Reports Server (NTRS)

Ralph, J. A.

1993-01-01

The application of advanced control concepts to air breathing engines may yield significant improvements in aircraft/engine performance and operability. Screening studies of advanced control concepts for air breathing engines were conducted by three major domestic aircraft engine manufacturers to determine the potential impact of concepts on turbine engine performance and operability. The purpose of the studies was to identify concepts which offered high potential yet may incur high research and development risk. A target suite of proposed advanced control concepts was formulated and evaluated in a two phase study to quantify each concept's impact on desired engine characteristics. To aid in the evaluation specific aircraft/engine combinations were considered: a Military High Performance Fighter mission, a High Speed Civil Transport mission, and a Civil Tiltrotor mission. Each of the advanced control concepts considered in the study are defined and described. The concept potential impact on engine performance was determined. Relevant figures of merit on which to evaluate the concepts are determined. Finally, the concepts are ranked with respect to the target aircraft/engine missions. A final report describing the screening studies was prepared by each engine manufacturer. Volume 1 of these reports describes the studies performed by Pratt & Whitney.

Advanced control for airbreathing engines, volume 2: General Electric aircraft engines

NASA Technical Reports Server (NTRS)

Bansal, Indar

1993-01-01

The application of advanced control concepts to air breathing engines may yield significant improvements in aircraft/engine performance and operability. Screening studies of advanced control concepts for air breathing engines were conducted by three major domestic aircraft engine manufacturers to determine the potential impact of concepts on turbine engine performance and operability. The purpose of the studies was to identify concepts which offered high potential yet may incur high research and development risk. A target suite of proposed advanced control concepts was formulated and evaluated in a two phase study to quantify each concept's impact on desired engine characteristics. To aid in the evaluation specific aircraft/engine combinations were considered: a Military High Performance Fighter mission, a High Speed Civil Transport mission, and a Civil Tiltrotor mission. Each of the advanced control concepts considered in the study are defined and described. The concept potential impact on engine performance was determined. Relevant figures of merit on which to evaluate the concepts are determined. Finally, the concepts are ranked with respect to the target aircraft/engine missions. A final report describing the screening studies was prepared by each engine manufacturer. Volume 2 of these reports describes the studies performed by GE Aircraft Engines.

Planar junctionless phototransistor: A potential high-performance and low-cost device for optical-communications

NASA Astrophysics Data System (ADS)

Ferhati, H.; Djeffal, F.

2017-12-01

In this paper, a new junctionless optical controlled field effect transistor (JL-OCFET) and its comprehensive theoretical model is proposed to achieve high optical performance and low cost fabrication process. Exhaustive study of the device characteristics and comparison between the proposed junctionless design and the conventional inversion mode structure (IM-OCFET) for similar dimensions are performed. Our investigation reveals that the proposed design exhibits an outstanding capability to be an alternative to the IM-OCFET due to the high performance and the weak signal detection benefit offered by this design. Moreover, the developed analytical expressions are exploited to formulate the objective functions to optimize the device performance using Genetic Algorithms (GAs) approach. The optimized JL-OCFET not only demonstrates good performance in terms of derived drain current and responsivity, but also exhibits superior signal to noise ratio, low power consumption, high-sensitivity, high ION/IOFF ratio and high-detectivity as compared to the conventional IM-OCFET counterpart. These characteristics make the optimized JL-OCFET potentially suitable for developing low cost and ultrasensitive photodetectors for high-performance and low cost inter-chips data communication applications.

Evaluation of Basalt Fibre Composites for Marine Applications

NASA Astrophysics Data System (ADS)

Davies, P.; Verbouwe, W.

2018-04-01

Basalt fibres offer potential for use in marine structures, but few data exist to evaluate the influence of seawater immersion on their mechanical behaviour. This paper provides the results from a study in which basalt fibre reinforced epoxy composites were aged in natural seawater at different temperatures. Tests were performed under quasi-static and cyclic loading, first in the as-received state then after saturation in natural seawater. Results are compared to those for an E-glass reinforced composite with the same epoxy matrix. They indicate similar mechanical performance for both materials after seawater saturation.

Multi-material Preforming of Structural Composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Norris, Robert E.; Eberle, Cliff C.; Pastore, Christopher M.

2015-05-01

Fiber-reinforced composites offer significant weight reduction potential, with glass fiber composites already widely adopted. Carbon fiber composites deliver the greatest performance benefits, but their high cost has inhibited widespread adoption. This project demonstrates that hybrid carbon-glass solutions can realize most of the benefits of carbon fiber composites at much lower cost. ORNL and Owens Corning Reinforcements along with program participants at the ORISE collaborated to demonstrate methods for produce hybrid composites along with techniques to predict performance and economic tradeoffs. These predictions were then verified in testing coupons and more complex demonstration articles.

The Nike-Black Brant V development program

NASA Technical Reports Server (NTRS)

Sevier, H.; Payne, B.; Ott, R.; Montag, W.

1976-01-01

The Nike-Black Brant V represents a combined U.S.-Canadian program to achieve a 40 percent increase in apogee performance over that of the unboosted BBV, with minimum component modification and no meaningful increase in flight environment levels. The process of achieving these objectives is described, in particular optimization of sustainer coast period and roll history, and the techniques used to ensure good stage separation. Details of the structural test program and subsequent successful vehicle proving flight are provided. Basic performance data are preented, with an indication of the further potential offered by Terrier boost.

Compact, Automated, Frequency-Agile Microspectrofluorimeter

NASA Technical Reports Server (NTRS)

Fernandez, Salvador M.; Guignon, Ernest F.

1995-01-01

Compact, reliable, rugged, automated cell-culture and frequency-agile microspectrofluorimetric apparatus developed to perform experiments involving photometric imaging observations of single live cells. In original application, apparatus operates mostly unattended aboard spacecraft; potential terrestrial applications include automated or semiautomated diagnosis of pathological tissues in clinical laboratories, biomedical instrumentation, monitoring of biological process streams, and portable instrumentation for testing biological conditions in various environments. Offers obvious advantages over present laboratory instrumentation.

Nanofluid Types, Their Synthesis, Properties and Incorporation in Direct Solar Thermal Collectors: A Review

PubMed Central

Chamsa-ard, Wisut; Brundavanam, Sridevi; Fung, Chun Che; Fawcett, Derek; Poinern, Gerrard

2017-01-01

The global demand for energy is increasing and the detrimental consequences of rising greenhouse gas emissions, global warming and environmental degradation present major challenges. Solar energy offers a clean and viable renewable energy source with the potential to alleviate the detrimental consequences normally associated with fossil fuel-based energy generation. However, there are two inherent problems associated with conventional solar thermal energy conversion systems. The first involves low thermal conductivity values of heat transfer fluids, and the second involves the poor optical properties of many absorbers and their coating. Hence, there is an imperative need to improve both thermal and optical properties of current solar conversion systems. Direct solar thermal absorption collectors incorporating a nanofluid offers the opportunity to achieve significant improvements in both optical and thermal performance. Since nanofluids offer much greater heat absorbing and heat transfer properties compared to traditional working fluids. The review summarizes current research in this innovative field. It discusses direct solar absorber collectors and methods for improving their performance. This is followed by a discussion of the various types of nanofluids available and the synthesis techniques used to manufacture them. In closing, a brief discussion of nanofluid property modelling is also presented. PMID:28561802

Thermoelectrics as elements of hybrid-electric vehicle thermal energy systems

NASA Astrophysics Data System (ADS)

Headings, Leon; Washington, Gregory; Jaworski, Christopher M.

2008-03-01

Despite vast technological improvements, the traditional internal combustion powered vehicle still achieves only 25- 30% efficiency, with the remainder lost primarily as heat. While the load leveling offered by hybrid-electric vehicle technology helps to improve this overall efficiency, part of the efficiency gains are achieved by making new systems such as regenerative braking viable. In a similar fashion, thermoelectric (TE) energy recovery has long been considered for traditional vehicles with mixed results, but little has been done to consider thermoelectrics in the framework of the unique energy systems of hybrid vehicles. Systems that may not have been viable or even possible with traditional vehicles may offer improvements to system efficiency as well as emissions, vehicle durability, passenger comfort, and cost. This research describes a simulation developed for evaluating and optimizing thermoelectric energy recovery systems and results for four different system configurations. Two novel system configurations are presented which offer the potential for additional benefits such as emissions reduction that will soon be quantified. In addition, a test setup is presented which was constructed for the testing and validation of various thermoelectric recovery systems. Actual test performance was near the expected theoretical performance and supported the conclusions reached from the computer simulations.

Nanofluid Types, Their Synthesis, Properties and Incorporation in Direct Solar Thermal Collectors: A Review.

PubMed

Chamsa-Ard, Wisut; Brundavanam, Sridevi; Fung, Chun Che; Fawcett, Derek; Poinern, Gerrard

2017-05-31

The global demand for energy is increasing and the detrimental consequences of rising greenhouse gas emissions, global warming and environmental degradation present major challenges. Solar energy offers a clean and viable renewable energy source with the potential to alleviate the detrimental consequences normally associated with fossil fuel-based energy generation. However, there are two inherent problems associated with conventional solar thermal energy conversion systems. The first involves low thermal conductivity values of heat transfer fluids, and the second involves the poor optical properties of many absorbers and their coating. Hence, there is an imperative need to improve both thermal and optical properties of current solar conversion systems. Direct solar thermal absorption collectors incorporating a nanofluid offers the opportunity to achieve significant improvements in both optical and thermal performance. Since nanofluids offer much greater heat absorbing and heat transfer properties compared to traditional working fluids. The review summarizes current research in this innovative field. It discusses direct solar absorber collectors and methods for improving their performance. This is followed by a discussion of the various types of nanofluids available and the synthesis techniques used to manufacture them. In closing, a brief discussion of nanofluid property modelling is also presented.

Queer Research and Queer Youth

ERIC Educational Resources Information Center

Talburt, Susan

2006-01-01

D'Augelli and Grossman's article offers an eloquent account of a complex longitudinal, interview-based study that surely has the potential to offer nuanced insights into the lives of lesbian, gay, and bisexual (LGB) youth. The authors' copious efforts to recruit, retain, and involve youth while avoiding potential dangers to them offer future…

Visual evoked potentials through night vision goggles.

PubMed

Rabin, J

1994-04-01

Night vision goggles (NVG's) have widespread use in military and civilian environments. NVG's amplify ambient illumination making performance possible when there is insufficient illumination for normal vision. While visual performance through NVG's is commonly assessed by measuring threshold functions such as visual acuity, few attempts have been made to assess vision through NVG's at suprathreshold levels of stimulation. Such information would be useful to better understand vision through NVG's across a range of stimulus conditions. In this study visual evoked potentials (VEP's) were used to evaluate vision through NVG's across a range of stimulus contrasts. The amplitude and latency of the VEP varied linearly with log contrast. A comparison of VEP's recorded with and without NVG's was used to estimate contrast attenuation through the device. VEP's offer an objective, electrophysiological tool to assess visual performance through NVG's at both threshold and suprathreshold levels of visual stimulation.

Evaluation of Advanced Composite Structures Technologies for Application to NASA's Vision for Space Exploration

NASA Technical Reports Server (NTRS)

Tenney, Darrel R.

2008-01-01

AS&M performed a broad assessment survey and study to establish the potential composite materials and structures applications and benefits to the Constellation Program Elements. Trade studies were performed on selected elements to determine the potential weight or performance payoff from use of composites. Weight predictions were made for liquid hydrogen and oxygen tanks, interstage cylindrical shell, lunar surface access module, ascent module liquid methane tank, and lunar surface manipulator. A key part of this study was the evaluation of 88 different composite technologies to establish their criticality to applications for the Constellation Program. The overall outcome of this study shows that composites are viable structural materials which offer from 20% to 40% weight savings for many of the structural components that make up the Major Elements of the Constellation Program. NASA investment in advancing composite technologies for space structural applications is an investment in America's Space Exploration Program.

Nanotube Reinforcement of Adhesively Bonded Joints

NASA Technical Reports Server (NTRS)

Johnson, W. S.; Saltysiak, Bethany

2002-01-01

Over the past five years there has been much excitement about the development of nanotubes and nanofibers and the potential that these materials may offer in enhancing electrical and mechanical properties of systems. The purpose of this paper is to present research into improving the mechanical performance of polymers by using nanofibers as a reinforcement to make high performance composite materials. This paper will present theoretical predictions of the composite modulus and then present the actual performance of the composite. Fabrication details will be given along with photos of the microstructure. The matrix material is polymethylmethacrylate (PMMA) and the nanofibers are vapor-grown carbon nanofibers produced by Pyrograph Products, Inc.

Nanotube Reinforcement of Adhesively Bonded Joints

NASA Technical Reports Server (NTRS)

Johnson, W. S.; Saltysiak, Bethany

2003-01-01

Over the past five years there has been much excitement about the development of nanotubes and nanofibers and the potential that these materials may offer in enhancing electrical and mechanical properties of systems. The purpose of this paper is to present research into improving the mechanical performance of polymers by using nanofibers as a reinforcement to make high performance composite materials. This paper will present theoretical predictions of the composite modulus and then present the actual performance of the composite. Fabrication details will be given along with photos of the microstructure. The matrix material is polymethylmethacrylate (PMMA) and the nanofibers are vapor-grown carbon nanofibers produced by Pyrograph Products, Inc.

Classification accuracy of claims-based methods for identifying providers failing to meet performance targets.

PubMed

Hubbard, Rebecca A; Benjamin-Johnson, Rhondee; Onega, Tracy; Smith-Bindman, Rebecca; Zhu, Weiwei; Fenton, Joshua J

2015-01-15

Quality assessment is critical for healthcare reform, but data sources are lacking for measurement of many important healthcare outcomes. With over 49 million people covered by Medicare as of 2010, Medicare claims data offer a potentially valuable source that could be used in targeted health care quality improvement efforts. However, little is known about the operating characteristics of provider profiling methods using claims-based outcome measures that may estimate provider performance with error. Motivated by the example of screening mammography performance, we compared approaches to identifying providers failing to meet guideline targets using Medicare claims data. We used data from the Breast Cancer Surveillance Consortium and linked Medicare claims to compare claims-based and clinical estimates of cancer detection rate. We then demonstrated the performance of claim-based estimates across a broad range of operating characteristics using simulation studies. We found that identification of poor performing providers was extremely sensitive to algorithm specificity, with no approach identifying more than 65% of poor performing providers when claims-based measures had specificity of 0.995 or less. We conclude that claims have the potential to contribute important information on healthcare outcomes to quality improvement efforts. However, to achieve this potential, development of highly accurate claims-based outcome measures should remain a priority. Copyright © 2014 John Wiley & Sons, Ltd.

Analogue mouse pointer control via an online steady state visual evoked potential (SSVEP) brain-computer interface

NASA Astrophysics Data System (ADS)

Wilson, John J.; Palaniappan, Ramaswamy

2011-04-01

The steady state visual evoked protocol has recently become a popular paradigm in brain-computer interface (BCI) applications. Typically (regardless of function) these applications offer the user a binary selection of targets that perform correspondingly discrete actions. Such discrete control systems are appropriate for applications that are inherently isolated in nature, such as selecting numbers from a keypad to be dialled or letters from an alphabet to be spelled. However motivation exists for users to employ proportional control methods in intrinsically analogue tasks such as the movement of a mouse pointer. This paper introduces an online BCI in which control of a mouse pointer is directly proportional to a user's intent. Performance is measured over a series of pointer movement tasks and compared to the traditional discrete output approach. Analogue control allowed subjects to move the pointer faster to the cued target location compared to discrete output but suffers more undesired movements overall. Best performance is achieved when combining the threshold to movement of traditional discrete techniques with the range of movement offered by proportional control.

Ares V: Application to Solar System Scientific Exploration

NASA Technical Reports Server (NTRS)

Elliott, John; Spilker, Thomas; Reh, Kim; Smith, David; Woodcock, Gordon

2008-01-01

The development of the Ares V launch vehicle will provide levels of performance unseen since the days of Apollo. This capability, like the Saturn V before it, is being developed primarily for crewed lunar missions. However, the tremendous jump in performance offered by the Ares V launch system has tremendous potential for the furtherance of robotic solar system exploration missions as well. Preliminary performance assessments indicate that Ares V could deliver 5 times the payload to Mars as compared to the most capable US expendable launch vehicle available today. Beyond Mars, the outer planets offer a number of high-priority investigations with compelling science. Presently, missions to these destinations are only achievable using indirect flights with gravity assist trajectories and, in many cases, suffer from long flight times. An Ares V with an upper stage could capture these missions using direct flights with shorter interplanetary transfer times that would enable extensive in situ investigations and possibly the return of samples to Earth. This paper lays out an estimate of Ares V performance for moderate and high C3 missions, and goes on to discuss a range of revolutionary mission concepts that could be enabled by this significant in-crease in launch capability.

Introduction into the Virtual Olympic Games Framework for online communities.

PubMed

Stoilescu, Dorian

2009-06-01

This paper presents the design of the Virtual Olympic Games Framework (VOGF), a computer application designated for athletics, health care, general well-being, nutrition and fitness, which offers multiple benefits for its participants. A special interest in starting the design of the framework was in exploring how people can connect and participate together using existing computer technologies (i.e. gaming consoles, exercise equipment with computer interfaces, devices of measuring health, speed, force and distance and Web 2.0 applications). A stationary bike set-up offering information to users about their individual health and athletic performances has been considered as a starting model. While this model is in the design stage, some preliminary findings are encouraging, suggesting the potential for various fields: sports, medicine, theories of learning, technologies and cybercultural studies. First, this framework would allow participants to perform a variety of sports and improve their health. Second, this would involve creating an online environment able to store health information and sport performances correlated with accessing multi-media data and research about performing sports. Third, participants could share experiences with other athletes, coaches and researchers. Fourth, this framework also provides support for the research community in their future investigations.

Do nurses who work in a fair organization sleep and perform better and why? Testing potential psychosocial mediators of organizational justice.

PubMed

Hietapakka, Laura; Elovainio, Marko; Heponiemi, Tarja; Presseau, Justin; Eccles, Martin; Aalto, Anna-Mari; Pekkarinen, Laura; Kuokkanen, Liisa; Sinervo, Timo

2013-10-01

We examined whether organizational justice is associated with sleep quality and performance in a population-based sample of 1,729 Finnish registered nurses working full time. In addition, we tested psychological mechanisms mediating the potential association. The results of multivariate linear regression analyses showed higher organizational justice to be associated with fewer sleeping problems (β values range from -.20 to -.11) and higher self-reported performance (β values range from .05 to .35). Furthermore, psychological distress (related to the psychological stress model) and job involvement (related to the psychosocial resource model) mediated the association between organizational justice and sleep. Sleeping problems partly mediated the association between organizational justice and performance. Psychological distress explained 51% to 83% and job involvement explained 10% to 15% of the total effects of justice variables on sleeping problems. The findings provide support for the psychological stress model and offer practical implications for reducing nurses' sleeping problems.

Preliminary investigation of an active PLZT lens

NASA Astrophysics Data System (ADS)

Peters, Bruce R.; Reardon, Patrick J.; Wong, K. J.

2001-05-01

The design analysis and preliminary testing of a prototype AFOCL is described. The AFOCL is an active optical component composed of solid state lead lanthanum-modified zirconate titanate (PLZT) ferroelectric ceramic with patterned indium tin oxide (ITO) transparent surface electrodes that modulate the refractive index of the PLZT to function as an electro- optic lens. The AFOCL was developed to perform optical re- alignment and wavefront correction to enhance the performance of Ultra-Lightweight Structures and Space Observatories. The AFOCL would be an active optical component within a larger optical system. Information from a wavefront sensor would be processed to provide input to the AFOCL to drive the sense4d wavefront tot he desired shape and location. While offering variable and rapid focusing capability similar to liquid crystal based spatial light modulators, the AFOCL offers some potential advantages because it is a solid-stat, stationary, low-mass, rugged, and thin optical element that can produce wavefront quality comparable to the solid refractive lens it replaces. The AFOCL acts as a positive or negative lens by producing a parabolic phase-shift in the PLZT material through the application of a controlled voltage potential across the ITO electrodes. To demonstrate the technology, a 4 mm diameter lens was fabricated to produce 5-waves of optical power operating at 2.051 micrometers wavelength. Optical metrology was performed on the device to measure focal length, optical quality, and efficiency for a variety of test configurations. Preliminary data was analyzed and compared to idealized performance available from computer-based models of the AFOCL.

Microfluidic desalination techniques and their potential applications.

PubMed

Roelofs, S H; van den Berg, A; Odijk, M

2015-09-07

In this review we discuss recent developments in the emerging research field of miniaturized desalination. Traditionally desalination is performed to convert salt water into potable water and research is focused on improving performance of large-scale desalination plants. Microfluidic desalination offers several new opportunities in comparison to macro-scale desalination, such as providing a platform to increase fundamental knowledge of ion transport on the nano- and microfluidic scale and new microfluidic sample preparation methods. This approach has also lead to the development of new desalination techniques, based on micro/nanofluidic ion-transport phenomena, which are potential candidates for up-scaling to (portable) drinking water devices. This review assesses microfluidic desalination techniques on their applications and is meant to contribute to further implementation of microfluidic desalination techniques in the lab-on-chip community.

Preliminary Evaluation of MapReduce for High-Performance Climate Data Analysis

NASA Technical Reports Server (NTRS)

Duffy, Daniel Q.; Schnase, John L.; Thompson, John H.; Freeman, Shawn M.; Clune, Thomas L.

2012-01-01

MapReduce is an approach to high-performance analytics that may be useful to data intensive problems in climate research. It offers an analysis paradigm that uses clusters of computers and combines distributed storage of large data sets with parallel computation. We are particularly interested in the potential of MapReduce to speed up basic operations common to a wide range of analyses. In order to evaluate this potential, we are prototyping a series of canonical MapReduce operations over a test suite of observational and climate simulation datasets. Our initial focus has been on averaging operations over arbitrary spatial and temporal extents within Modern Era Retrospective- Analysis for Research and Applications (MERRA) data. Preliminary results suggest this approach can improve efficiencies within data intensive analytic workflows.

Extremophiles and biotechnology: current uses and prospects

PubMed Central

Coker, James A.

2016-01-01

Biotechnology has almost unlimited potential to change our lives in very exciting ways. Many of the chemical reactions that produce these products can be fully optimized by performing them at extremes of temperature, pressure, salinity, and pH for efficient and cost-effective outcomes. Fortunately, there are many organisms (extremophiles) that thrive in extreme environments found in nature and offer an excellent source of replacement enzymes in lieu of mesophilic ones currently used in these processes. In this review, I discuss the current uses and some potential new applications of extremophiles and their products, including enzymes, in biotechnology. PMID:27019700

The Future of Satellite-based Lightning Detection

NASA Technical Reports Server (NTRS)

Bocippio, Dennis J.; Christian, Hugh J.; Arnold, James E. (Technical Monitor)

2001-01-01

The future of satellite-based optical lightning detection, beyond the end of the current TRMM mission, is discussed. Opportunities for new low-earth orbit missions are reviewed. The potential for geostationary observations is significant; such observations provide order-of-magnitude gains in sampling and data efficiency over existing satellite convective observations. The feasibility and performance (resolution, sensitivity) of geostationary measurements using current technology is discussed. In addition to direct and continuous hemispheric observation of lighting, geostationary measurements have the potential (through data assimilation) to dramatically improve short and medium range forecasts, offering benefits to prediction of NOx productions and/or vertical transport.

DigiMesh Reliability in High Speed Vehicular Applications

NASA Astrophysics Data System (ADS)

Visan, Bogdan A.

In a fast-paced technological society, advances in wireless networking show potential to save lives. Communication is key to notifying Emergency Medical Services of a potentially deadly accident in near real-time. This paper will discuss the use of low powered wireless devices transmitting life-saving information autonomously. Current and planned technologies used in vehicles are built-in, costly, and vulnerable to physical destruction. Using an independent system can offer both old and new vehicles primary and secondary communication. The results from this research study show that vehicles can use DigiMesh as a viable solution, although relative velocity affects its performance.

Development and Validation of a Multimedia-based Assessment of Scientific Inquiry Abilities

NASA Astrophysics Data System (ADS)

Kuo, Che-Yu; Wu, Hsin-Kai; Jen, Tsung-Hau; Hsu, Ying-Shao

2015-09-01

The potential of computer-based assessments for capturing complex learning outcomes has been discussed; however, relatively little is understood about how to leverage such potential for summative and accountability purposes. The aim of this study is to develop and validate a multimedia-based assessment of scientific inquiry abilities (MASIA) to cover a more comprehensive construct of inquiry abilities and target secondary school students in different grades while this potential is leveraged. We implemented five steps derived from the construct modeling approach to design MASIA. During the implementation, multiple sources of evidence were collected in the steps of pilot testing and Rasch modeling to support the validity of MASIA. Particularly, through the participation of 1,066 8th and 11th graders, MASIA showed satisfactory psychometric properties to discriminate students with different levels of inquiry abilities in 101 items in 29 tasks when Rasch models were applied. Additionally, the Wright map indicated that MASIA offered accurate information about students' inquiry abilities because of the comparability of the distributions of student abilities and item difficulties. The analysis results also suggested that MASIA offered precise measures of inquiry abilities when the components (questioning, experimenting, analyzing, and explaining) were regarded as a coherent construct. Finally, the increased mean difficulty thresholds of item responses along with three performance levels across all sub-abilities supported the alignment between our scoring rubrics and our inquiry framework. Together with other sources of validity in the pilot testing, the results offered evidence to support the validity of MASIA.

On a High-Performance VLSI Solution to Database Problems.

DTIC Science & Technology

1981-08-01

offer such attractive features as automatic verification and. maintenance of semantic integrity, usage of views as abstraction and authorization...course, is the waste of too much potential resource. The global database may contain information for many different users and applications. In processing...working on, this may cause no damage at all, but some waste of space. Therefore one solution may be perhaps to do nothing to prevent its occurrence

High-Temperature Alloys for Automotive Stirling Engines

NASA Technical Reports Server (NTRS)

Stephens, J. R.; Titran, R. H.

1986-01-01

Stirling engine is external-combustion engine that offers fuel economy, low emissions, low noise, and low vibrations. One of most critical areas in engine development concerns material selection for component parts. Alloys CG-27 and XF-818 identified capable of withstanding rigorous requirements of automotive Stirling engine. Alloys chosen for availability, performance, and manufacturability. Advanced iron-base alloys have potential for variety of applications, including stationary solar-power systems.

Dynamic Behavior and Optimization of Advanced Armor Ceramics: January-December 2011 Annual Report

DTIC Science & Technology

2015-03-01

however, under conventional methods of processing. To develop plasticity in ceramic like SiC, new fracture mechanisms and interesting behaviors need...and new fracture mechanisms . These improvements, in turn, could offer the potential for improved ballistic performance. Co-precipitation has been...experiments, the following deformed fragments were recovered for extensive SEM and TEM study.  A fracture mechanism map has been constructed in

Nanofiber adsorbents for high productivity downstream processing.

PubMed

Hardick, Oliver; Dods, Stewart; Stevens, Bob; Bracewell, Daniel G

2013-04-01

Electrospun polymeric nanofiber adsorbents offer an alternative ligand support surface for bioseparations. Their non-woven fiber structure with diameters in the sub-micron range creates a remarkably high surface area. To improve the purification productivity of biological molecules by chromatography, cellulose nanofiber adsorbents were fabricated and assembled into a cartridge and filter holder format with a volume of 0.15 mL, a bed height of 0.3 mm and diameter of 25 mm. The present study investigated the performance of diethylaminoethyl (DEAE) derivatized regenerated cellulose nanofiber adsorbents based on criteria including mass transfer and flow properties, binding capacity, and fouling effects. Our results show that nanofibers offer higher flow and mass transfer properties. The non-optimized DEAE-nanofiber adsorbents indicate a binding capacity of 10% that of packed bed systems with BSA as a single component system. However, they operate reproducibly at flowrates of a hundred times that of packed beds, resulting in a potential productivity increase of 10-fold. Lifetime studies showed that this novel adsorbent material operated reproducibly with complex feed material (centrifuged and 0.45 µm filtered yeast homogenate) and harsh cleaning-in-place conditions over multiple cycles. DEAE nanofibers showed superior operating performance in permeability and fouling over conventional adsorbents indicating their potential for bioseparation applications. Copyright © 2012 Wiley Periodicals, Inc.

Trends, Opportunities, and Challenges for Tall Wind Turbine and Tower Technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lantz, Eric; Roberts, Owen; Dykes, Katherine

This presentation summarizes recent analysis focused on characterizing the opportunity for Tall Wind technologies generally and for tall tower technologies specifically. It seeks to illuminate and explain the concept of Tall Wind, its impact on the wind industry to date, and the potential value of Tall Wind in the future. It also explores the conditions and locations under which the impacts of Tall Wind offer the most significant potential to increase wind technology performance. In addition, it seeks to examine the status of tall tower technology as a key sub-component of Tall Wind, focusing on the potential for continued innovationmore » in tubular steel wind turbine towers and the status and potential for a select set of alternative tall tower technologies.« less

The TensorMol-0.1 model chemistry: a neural network augmented with long-range physics.

PubMed

Yao, Kun; Herr, John E; Toth, David W; Mckintyre, Ryker; Parkhill, John

2018-02-28

Traditional force fields cannot model chemical reactivity, and suffer from low generality without re-fitting. Neural network potentials promise to address these problems, offering energies and forces with near ab initio accuracy at low cost. However a data-driven approach is naturally inefficient for long-range interatomic forces that have simple physical formulas. In this manuscript we construct a hybrid model chemistry consisting of a nearsighted neural network potential with screened long-range electrostatic and van der Waals physics. This trained potential, simply dubbed "TensorMol-0.1", is offered in an open-source Python package capable of many of the simulation types commonly used to study chemistry: geometry optimizations, harmonic spectra, open or periodic molecular dynamics, Monte Carlo, and nudged elastic band calculations. We describe the robustness and speed of the package, demonstrating its millihartree accuracy and scalability to tens-of-thousands of atoms on ordinary laptops. We demonstrate the performance of the model by reproducing vibrational spectra, and simulating the molecular dynamics of a protein. Our comparisons with electronic structure theory and experimental data demonstrate that neural network molecular dynamics is poised to become an important tool for molecular simulation, lowering the resource barrier to simulating chemistry.

Routine health insurance data for scientific research: potential and limitations of the Agis Health Database.

PubMed

Smeets, Hugo M; de Wit, Niek J; Hoes, Arno W

2011-04-01

Observational studies performed within routine health care databases have the advantage of their large size and, when the aim is to assess the effect of interventions, can offer a completion to randomized controlled trials with usually small samples from experimental situations. Institutional Health Insurance Databases (HIDs) are attractive for research because of their large size, their longitudinal perspective, and their practice-based information. As they are based on financial reimbursement, the information is generally reliable. The database of one of the major insurance companies in the Netherlands, the Agis Health Database (AHD), is described in detail. Whether the AHD data sets meet the specific requirements to conduct several types of clinical studies is discussed according to the classification of the four different types of clinical research; that is, diagnostic, etiologic, prognostic, and intervention research. The potential of the AHD for these various types of research is illustrated using examples of studies recently conducted in the AHD. HIDs such as the AHD offer large potential for several types of clinical research, in particular etiologic and intervention studies, but at present the lack of detailed clinical information is an important limitation. Copyright © 2011 Elsevier Inc. All rights reserved.

Making the case for mobile cognition: EEG and sports performance.

PubMed

Park, Joanne L; Fairweather, Malcolm M; Donaldson, David I

2015-05-01

In the high stakes world of International sport even the smallest change in performance can make the difference between success and failure, leading sports professionals to become increasingly interested in the potential benefits of neuroimaging. Here we describe evidence from EEG studies that either identify neural signals associated with expertise in sport, or employ neurofeedback to improve performance. Evidence for the validity of neurofeedback as a technique for enhancing sports performance remains limited. By contrast, progress in characterizing the neural correlates of sporting behavior is clear: frequency domain studies link expert performance to changes in alpha rhythms, whilst time-domain studies link expertise in response evaluation and motor output with modulations of P300 effects and readiness potentials. Despite early promise, however, findings have had relatively little impact for sports professionals, at least in part because there has been a mismatch between lab tasks and real sporting activity. After selectively reviewing existing findings and outlining limitations, we highlight developments in mobile EEG technology that offer new opportunities for sports neuroscience. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Design and evaluation of experimental ceramic automobile thermal reactors

NASA Technical Reports Server (NTRS)

Stone, P. L.; Blankenship, C. P.

1974-01-01

The paper summarizes the results obtained in an exploratory evaluation of ceramics for automobile thermal reactors. Candidate ceramic materials were evaluated in several reactor designs using both engine dynamometer and vehicle road tests. Silicon carbide contained in a corrugated metal support structure exhibited the best performance, lasting 1100 hours in engine dynamometer tests and for more than 38,600 kilimeters (24,000 miles) in vehicle road tests. Although reactors containing glass-ceramic components did not perform as well as silicon carbide, the glass-ceramics still offer good potential for reactor use with improved reactor designs.

Design and evaluation of experimental ceramic automobile thermal reactors

NASA Technical Reports Server (NTRS)

Stone, P. L.; Blankenship, C. P.

1974-01-01

The results obtained in an exploratory evaluation of ceramics for automobile thermal reactors are summarized. Candidate ceramic materials were evaluated in several reactor designs by using both engine-dynamometer and vehicle road tests. Silicon carbide contained in a corrugated-metal support structure exhibited the best performance, lasting 1100 hr in engine-dynamometer tests and more than 38,600 km (24000 miles) in vehicle road tests. Although reactors containing glass-ceramic components did not perform as well as those containing silicon carbide, the glass-ceramics still offer good potential for reactor use with improved reactor designs.

LWIR detector requirements for low-background space applications

NASA Technical Reports Server (NTRS)

Deluccia, Frank J.

1990-01-01

Detection of cold bodies (200 to 300 K) against space backgrounds has many important applications, both military and non-military. The detector performance and design characteristics required to support low-background applications are discussed, with particular emphasis on those characteristics required for space surveillance. The status of existing detector technologies under active development for these applications is also discussed. In order to play a role in future systems, new, potentially competing detector technologies such as multiple quantum well detectors must not only meet system-derived requirements, but also offer distinct performance or other advantages over these incumbent technologies.

Potential clinical applications of photoacoustics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosencwaig, A.

1982-09-01

Photoacoustic spectroscopy offers the opportunity for extending the exact science of noninvasive spectral analysis to intact medical substances such as tissues. Thermal-wave imaging offers the potential for microscopic imaging of thermal features in biological matter.

Virtual reality training and assessment in laparoscopic rectum surgery.

PubMed

Pan, Jun J; Chang, Jian; Yang, Xiaosong; Liang, Hui; Zhang, Jian J; Qureshi, Tahseen; Howell, Robert; Hickish, Tamas

2015-06-01

Virtual-reality (VR) based simulation techniques offer an efficient and low cost alternative to conventional surgery training. This article describes a VR training and assessment system in laparoscopic rectum surgery. To give a realistic visual performance of interaction between membrane tissue and surgery tools, a generalized cylinder based collision detection and a multi-layer mass-spring model are presented. A dynamic assessment model is also designed for hierarchy training evaluation. With this simulator, trainees can operate on the virtual rectum with both visual and haptic sensation feedback simultaneously. The system also offers surgeons instructions in real time when improper manipulation happens. The simulator has been tested and evaluated by ten subjects. This prototype system has been verified by colorectal surgeons through a pilot study. They believe the visual performance and the tactile feedback are realistic. It exhibits the potential to effectively improve the surgical skills of trainee surgeons and significantly shorten their learning curve. Copyright © 2014 John Wiley & Sons, Ltd.

Micromechanics and Structural Response of Functionally Graded, Particulate-Matrix, Fiber-Reinforced Composites

PubMed Central

Genin, Guy M.; Birman, Victor

2009-01-01

Reinforcement of fibrous composites by stiff particles embedded in the matrix offers the potential for simple, economical functional grading, enhanced response to mechanical loads, and improved functioning at high temperatures. Here, we consider laminated plates made of such a material, with spherical reinforcement tailored by layer. The moduli for this material lie within relatively narrow bounds. Two separate moduli estimates are considered: a “two-step” approach in which fibers are embedded in a homogenized particulate matrix, and the Kanaun-Jeulin (2001) approach, which we re-derive in a simple way using the Benveniste (1988) method. Optimal tailoring of a plate is explored, and functional grading is shown to improve the performance of the structures considered. In the example of a square, simply supported, cross-ply laminated panel subjected to uniform transverse pressure, a modest functional grading offers significant improvement in performance. A second example suggests superior blast resistance of the panel achieved at the expense of only a small increase in weight. PMID:23874001

Comparative measurements of plasma potential with ball-pen and Langmuir probe in low-temperature magnetized plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zanáška, M.; Kudrna, P.; Tichý, M.

The ball-pen probe (BPP) is used for direct plasma potential measurements in magnetized plasma. The probe can adjust the ratio of the electron and ion saturation currents I{sub sat}{sup −}/I{sub sat}{sup +} to be close to one and therefore its I-V characteristic becomes nearly symmetric. If this is achieved, the floating potential of the BPP is close to the plasma potential. Because of its rather simple construction, it offers an attractive probe for measurements in magnetized plasma. Comparative measurements of plasma potential by BPPs of different dimensions as well as one Langmuir probe (LP) in an argon discharge plasma ofmore » a cylindrical magnetron were performed at various experimental conditions. An additional comparison by an emissive probe was also performed. All these types of probes provide similar values of plasma potential in a wide range of plasma parameters. Our results for three different BPP dimensions indicate that the BPP can be operated in a cylindrical magnetron DC argon discharge if the value of the ratio of the magnetic field and neutral gas pressure, B/p, is greater than approximately 10 mT/Pa.« less

Nanomagnet Logic: Architectures, design, and benchmarking

NASA Astrophysics Data System (ADS)

Kurtz, Steven J.

Nanomagnet Logic (NML) is an emerging technology being studied as a possible replacement or supplementary device for Complimentary Metal-Oxide-Semiconductor (CMOS) Field-Effect Transistors (FET) by the year 2020. NML devices offer numerous potential advantages including: low energy operation, steady state non-volatility, radiation hardness and a clear path to fabrication and integration with CMOS. However, maintaining both low-energy operation and non-volatility while scaling from the device to the architectural level is non-trivial as (i) nearest neighbor interactions within NML circuits complicate the modeling of ensemble nanomagnet behavior and (ii) the energy intensive clock structures required for re-evaluation and NML's relatively high latency challenge its ability to offer system-level performance wins against other emerging nanotechnologies. Thus, further research efforts are required to model more complex circuits while also identifying circuit design techniques that balance low-energy operation with steady state non-volatility. In addition, further work is needed to design and model low-power on-chip clocks while simultaneously identifying application spaces where NML systems (including clock overhead) offer sufficient energy savings to merit their inclusion in future processors. This dissertation presents research advancing the understanding and modeling of NML at all levels including devices, circuits, and line clock structures while also benchmarking NML against both scaled CMOS and tunneling FETs (TFET) devices. This is accomplished through the development of design tools and methodologies for (i) quantifying both energy and stability in NML circuits and (ii) evaluating line-clocked NML system performance. The application of these newly developed tools improves the understanding of ideal design criteria (i.e., magnet size, clock wire geometry, etc.) for NML architectures. Finally, the system-level performance evaluation tool offers the ability to project what advancements are required for NML to realize performance improvements over scaled-CMOS hardware equivalents at the functional unit and/or application-level.

Microlith-based Structured Sorbent for Carbon Dioxide, Humidity, and Trace Contaminant Control in Manned Space Habitats

NASA Technical Reports Server (NTRS)

Junaedi, Christian; Roychoudhury, SUbir; Howard, David F.; Perry, Jay L.; Knox, James C.

2011-01-01

To support continued manned space exploration, the development of atmosphere revitalization systems that are lightweight, compact, durable, and power efficient is a key challenge. The systems should be adaptable for use in a variety of habitats and should offer operational functionality to either expel removed constituents or capture them for closedloop recovery. As mission durations increase and exploration goals reach beyond low earth orbit, the need for regenerable adsorption processes for continuous removal of CO2 and trace contaminants from cabin air becomes critical. Precision Combustion, Inc. (PCI) and NASA Marshall (MSFC) have been developing an Engineered Structured Sorbents (ESS) approach based on PCI s patented Microlith technology to meet the requirements of future, extended human spaceflight explorations. This technology offers the inherent performance and safety attributes of zeolite and other sorbents with greater structural integrity, regenerability, and process control, thereby providing potential durability and efficiency improvements over current state-of-the-art systems. The major advantages of the ESS explored in this study are realized through the use of metal substrates to provide structural integrity (i.e., less partition of sorbents) and enhanced thermal control during the sorption process. The Microlith technology also offers a unique internal resistive heating capability that shows potential for short regeneration time and reduced power requirement compared to conventional systems. This paper presents the design, development, and performance results of the integrated adsorber modules for removing CO2, water vapor, and trace chemical contaminants. A related effort that utilizes the adsorber modules for sorption of toxic industrial chemicals is also discussed. Finally, the development of a 4-person two-leg ESS system for continuous CO2 removal is also presented.

Evaluation of center-cut separations applying simulated moving bed chromatography with 8 zones.

PubMed

Santos da Silva, Francisco Vitor; Seidel-Morgenstern, Andreas

2016-07-22

Different multi-column options to perform continuous chromatographic separations of ternary mixtures have been proposed in order to overcome limitations of batch chromatography. One attractive option is given by simulated moving bed chromatography (SMB) with 8 zones, a process that offers uninterrupted production, and, potentially, improved economy. As in other established ternary separation processes, the separation sequence is crucial for the performance of the process. This problem is addressed here by computing and comparing optimal performances of the two possibilities assuming linear adsorption isotherms. The conclusions are presented in a decision tree which can be used to guide the selection of system configuration and operation. Copyright © 2016 Elsevier B.V. All rights reserved.

A Solar Dynamic Power Option for Space Solar Power

NASA Technical Reports Server (NTRS)

Mason, Lee S.

1999-01-01

A study was performed to determine the potential performance and related technology requirements of Solar Dynamic power systems for a Space Solar Power satellite. Space Solar Power is a concept where solar energy is collected in orbit and beamed to Earth receiving stations to supplement terrestrial electric power service. Solar Dynamic systems offer the benefits of high solar-to-electric efficiency, long life with minimal performance degradation, and high power scalability. System analyses indicate that with moderate component development, SD systems can exhibit excellent mass and deployed area characteristics. Using the analyses as a guide, a technology roadmap was -enerated which identifies the component advances necessary to make SD power generation a competitive option for the SSP mission.

Integrated Power and Attitude Control System (IPACS) technology developments

NASA Technical Reports Server (NTRS)

Eisenhaure, David B.; Bechtel, Robert; Hockney, Richard; Oglevie, Ron; Olszewski, Mitch

1990-01-01

Integrated Power and Attitude Control System (IPACS) studies performed over a decade ago established the feasibility of storing electrical energy in flywheels and utilizing the resulting angular momentum for spacecraft attitude control. Such a system has been shown to have numerous attractive features relative to more contemporary technology, and is appropriate to many applications (including high-performance slewing actuators). Technology advances over the last two decades in composite rotors, motor/generator/electronics, and magnetic bearings are found to support the use of IPACS for increasingly sophisticated applications. It is concluded that the concept offers potential performance advantages as well as savings in mass and life-cycle cost. Viewgraphs and discussion on IPACS are included.

Combined evoked potentials in co-occuring attention deficit hyperactivity disorder and epilepsy.

PubMed

Major, Zoltán Zsigmond

2011-07-30

Evoked potentials, both stimulus related and event related, show disturbances in attention deficit-hyperactivity disorder and epilepsies, too. This study was designed to evaluate if these potentials are characteristically influenced by the presence of the two diseases, individually, and in the case of co-occurrence. Forty children were included, and four groups were formed, control group, ADHD group, epilepsy group and a group with the comorbidity of epilepsy and ADHD. Epilepsy patients were under proper antiepileptic treatment; ADHD patients were free of specific therapy. Brainstem auditory evoked potentials, visual evoked potentials and auditory P300 evaluation were performed. The latency of the P100 and N135 visual evoked potential components was significantly extended by the presence of epilepsy. If ADHD was concomitantly present, this effect was attenuated. Brainstem auditory evoked potential components were prolonged in the presence of the comorbidity, considering the waves elicited in the brainstem. P300 latencies were prolonged by the presence of co-occurring ADHD and epilepsy. Feedback parameters showed overall reduction of the tested cognitive performances in the ADHD group. Disturbances produced by the presence of ADHD-epilepsy comorbidity reveal hypothetically a linked physiopathological path for both diseases, and offers an approach with possible diagnostic importance, combined evoked potential recordings.

Generalized Abstract Symbolic Summaries

NASA Technical Reports Server (NTRS)

Person, Suzette; Dwyer, Matthew B.

2009-01-01

Current techniques for validating and verifying program changes often consider the entire program, even for small changes, leading to enormous V&V costs over a program s lifetime. This is due, in large part, to the use of syntactic program techniques which are necessarily imprecise. Building on recent advances in symbolic execution of heap manipulating programs, in this paper, we develop techniques for performing abstract semantic differencing of program behaviors that offer the potential for improved precision.

Training potential in minimally invasive surgery in a tertiary care, paediatric urology centre.

PubMed

Schroeder, R P J; Chrzan, R J; Klijn, A J; Kuijper, C F; Dik, P; de Jong, T P V M

2015-10-01

Minimally invasive surgery (MIS) is being utilized more frequently as a surgical technique in general surgery and in paediatric urology. It is associated with a steep learning curve. Currently, the centre does not offer a MIS training programme. It is hypothesized that the number of MIS procedures performed in the low-volume specialty of paediatric urology will offer insufficient training potential for surgeons. To assess the MIS training potential of a highly specialized, tertiary care, paediatric urology training centre that has been accredited by the Joint Committee of Paediatric Urology (JCPU). The clinical activity of the department was retrospectively reviewed by extracting the annual number of admissions, outpatient consultations and operative procedures. The operations were divided into open procedures and MIS. Major ablative procedures (nephrectomy) and reconstructive procedures (pyeloplasty) were analysed with reference to the patients' ages. The centre policy is not to perform major MIS in children who are under 2 years old or who weigh less than 12 kg. Every year, this institution provides approximately 4300 out-patient consultations, 600 admissions, and 1300 procedures under general anaesthesia for children with urological problems. In 2012, 35 patients underwent major intricate MIS: 16 pyeloplasties, eight nephrectomies and 11 operations for incontinence (seven Burch, and four bladder neck procedures). In children ≥2 years of age, 16/21 of the pyeloplasties and 8/12 of the nephrectomies were performed laparoscopically. The remaining MIS procedures included 25 orchidopexies and one intravesical ureteral reimplantation. There is no consensus on how to assess laparoscopic training. It would be valuable to reach a consensus on a standardized laparoscopic training programme in paediatric urology. Often training potential is based on operation numbers only. In paediatric urology no minimum requirement has been specified. The number of procedures quoted for proficiency in MIS remains controversial. The MIS numbers for this centre correspond to, or exceed, numbers mentioned in other literature. To provide high-quality MIS training, exposure to laparoscopic procedures should be expanded. This may be achieved by centralizing patients into a common centre, collaborating with other specialities, modular training and training outside the operating theatre. Even in a high-volume, paediatric urology educational centre, the number of major MIS procedures performed remains relatively low, leading to limited training potential. Copyright © 2015. Published by Elsevier Ltd.

Development, Testing, and Validation of a Model-Based Tool to Predict Operator Responses in Unexpected Workload Transitions

NASA Technical Reports Server (NTRS)

Sebok, Angelia; Wickens, Christopher; Sargent, Robert

2015-01-01

One human factors challenge is predicting operator performance in novel situations. Approaches such as drawing on relevant previous experience, and developing computational models to predict operator performance in complex situations, offer potential methods to address this challenge. A few concerns with modeling operator performance are that models need to realistic, and they need to be tested empirically and validated. In addition, many existing human performance modeling tools are complex and require that an analyst gain significant experience to be able to develop models for meaningful data collection. This paper describes an effort to address these challenges by developing an easy to use model-based tool, using models that were developed from a review of existing human performance literature and targeted experimental studies, and performing an empirical validation of key model predictions.

The NASA/USAF arcjet research and technology program

NASA Technical Reports Server (NTRS)

Stone, James R.; Huston, Edward S.

1987-01-01

Direct current arcjets have the potential to provide specific impulses greater than 500 sec with storable propellants, and greater than 1000 sec with hydrogen. This level of performance can provide significant benefits for such applications as orbit transfer, station keeping, orbit change, and maneuvering. The simplicity of the arcjet system and its elements of commonality with state-of-the-art resistojet systems offer a relatively low risk transition to these enhanced levels of performance for low power (0.5 to 1.5 kW) station keeping applications. Arcjets at power levels of 10 to 30 kW are potentially applicable to orbit transfer missions. Furthermore, with the anticipated development of space nuclear power systems, arcjets at greater than 100 kW may become attractive. This paper describes the ongoing NASA/USAF program and describes major recent accomplishments.

Energy and momentum management of the Space Station using magnetically suspended composite rotors

NASA Technical Reports Server (NTRS)

Eisenhaure, D. B.; Oglevie, R. E.; Keckler, C. R.

1985-01-01

The research addresses the feasibility of using magnetically suspended composite rotors to jointly perform the energy and momentum management functions of an advanced manned Space Station. Recent advancements in composite materials, magnetic suspensions, and power conversion electronics have given flywheel concepts the potential to simultaneously perform these functions for large, long duration spacecraft, while offering significant weight, volume, and cost savings over conventional approaches. The Space Station flywheel concept arising out of this study consists of a composite-material rotor, a large-angle magnetic suspension (LAMS) system, an ironless armature motor/generator, and high-efficiency power conversion electronics. The LAMS design permits the application of appropriate spacecraft control torques without the use of conventional mechanical gimbals. In addition, flywheel systems have the growth potential and modularity needed to play a key role in many future system developments.

A review of failure models for unidirectional ceramic matrix composites under monotonic loads

NASA Technical Reports Server (NTRS)

Tripp, David E.; Hemann, John H.; Gyekenyesi, John P.

1989-01-01

Ceramic matrix composites offer significant potential for improving the performance of turbine engines. In order to achieve their potential, however, improvements in design methodology are needed. In the past most components using structural ceramic matrix composites were designed by trial and error since the emphasis of feasibility demonstration minimized the development of mathematical models. To understand the key parameters controlling response and the mechanics of failure, the development of structural failure models is required. A review of short term failure models with potential for ceramic matrix composite laminates under monotonic loads is presented. Phenomenological, semi-empirical, shear-lag, fracture mechanics, damage mechanics, and statistical models for the fast fracture analysis of continuous fiber unidirectional ceramic matrix composites under monotonic loads are surveyed.

Direct patterning of organic conductors on knitted textiles for long-term electrocardiography

NASA Astrophysics Data System (ADS)

Takamatsu, Seiichi; Lonjaret, Thomas; Crisp, Dakota; Badier, Jean-Michel; Malliaras, George G.; Ismailova, Esma

2015-10-01

Wearable sensors are receiving a great deal of attention as they offer the potential to become a key technological tool for healthcare. In order for this potential to come to fruition, new electroactive materials endowing high performance need to be integrated with textiles. Here we present a simple and reliable technique that allows the patterning of conducting polymers on textiles. Electrodes fabricated using this technique showed a low impedance contact with human skin, were able to record high quality electrocardiograms at rest, and determine heart rate even when the wearer was in motion. This work paves the way towards imperceptible electrophysiology sensors for human health monitoring.

The Advanced Gamma-ray Imaging System (AGIS): A Nanosecond Time Scale Stereoscopic Array Trigger System.

NASA Astrophysics Data System (ADS)

Krennrich, Frank; Buckley, J.; Byrum, K.; Dawson, J.; Drake, G.; Horan, D.; Krawzcynski, H.; Schroedter, M.

2008-04-01

Imaging atmospheric Cherenkov telescope arrays (VERITAS, HESS) have shown unprecedented background suppression capabilities for reducing cosmic-ray induced air showers, muons and night sky background fluctuations. Next-generation arrays with on the order of 100 telescopes offer larger collection areas, provide the possibility to see the air shower from more view points on the ground, have the potential to improve the sensitivity and give additional background suppression. Here we discuss the design of a fast array trigger system that has the potential to perform a real time image analysis allowing substantially improved background rate suppression at the trigger level.

Magnetic conveyor belt for transporting and merging trapped atom clouds.

PubMed

Hänsel, W; Reichel, J; Hommelhoff, P; Hänsch, T W

2001-01-22

We demonstrate an integrated magnetic device which transports cold atoms near a surface with very high positioning accuracy. Time-dependent currents in a lithographic conductor pattern create a moving chain of potential wells; atoms are transported in these wells while remaining confined in all three dimensions. We achieve mean fluxes up to 10(6) s(-1) with a negligible heating rate. An extension of this device allows merging of atom clouds by unification of two Ioffe-Pritchard potentials. The unification, which we demonstrate experimentally, can be performed without loss of phase space density. This novel, all-magnetic atom manipulation offers exciting perspectives, such as trapped-atom interferometry.

Novel Insights Into Causes of Scleroderma Offer Potential New Treatment Strategies

MedlinePlus

... Novel Insights Into Causes of Scleroderma Offer Potential New Treatment Strategies By Kirstie Saltsman, Ph.D. | December ... address the immune system’s role thanks to a new mouse model of scleroderma, which mirrors many aspects ...

Psychological interventions for housebound people with psychosis: service user and therapist perspectives in South East London.

PubMed

Iredale, Catherine; Fornells-Ambrojo, Miriam; Jolley, Suzanne

2016-06-01

People with psychosis often have difficulty leaving their homes to perform tasks of daily living, which also limits their access to clinic-based interventions to support recovery. Home-based psychological therapy may offer a solution. To examine service user and therapist perspectives on (i) houseboundness in psychosis and (ii) the value of home-based psychological interventions, as a first step towards a systematic evaluation. Semistructured interviews with 10 service users and 12 therapists from a large inner city mental health NHS Foundation Trust were thematically analysed. Houseboundness most commonly resulted from anxiety, paranoia and amotivation, indicating the potential usefulness of targeted psychological therapies. Home-based therapy was offered unsystematically, with variable goals. Although beneficial for engagement and assessment, little gain was reported from undertaking a full course of therapy at home. Home visits could be offered by psychological therapists to engage and assess housebound service users, but home-based therapy may be best offered on a short-term basis, targeting paranoia, anxiety and amotivation to increase access to other resources. Given the increased cost associated with home-based psychological interventions, a systematic evaluation of their impact is warranted.

Technical assessment of maglev system concepts. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lever, J.H.

1998-10-01

The Government Maglev System Assessment Team operated from 1991 to 1993 as part of the National Maglev Initiative. They assessed the technical viability of four US Maglev system concepts, using the French TGV high speed train and the German TR07 Maglev system as assessment baselines. Maglev in general offers advantages that include high speed potential, excellent system control, high capacity, low energy consumption, low maintenance, modest land requirements, low operating costs, and ability to meet a variety of transportation missions. Further, the US Maglev concepts could provide superior performance to TR07 for similar cost or similar performance for less cost.more » They also could achieve both lower trip times and lower energy consumption along typical US routes. These advantages result generally from the use of large gap magnetic suspensions, more powerful linear synchronous motors and tilting vehicles. Innovative concepts for motors, guideways, suspension, and superconducting magnets all contribute to a potential for superior long term performance of US Maglev systems compared with TGV and TR07.« less

F-8C adaptive flight control laws

NASA Technical Reports Server (NTRS)

Hartmann, G. L.; Harvey, C. A.; Stein, G.; Carlson, D. N.; Hendrick, R. C.

1977-01-01

Three candidate digital adaptive control laws were designed for NASA's F-8C digital flyby wire aircraft. Each design used the same control laws but adjusted the gains with a different adaptative algorithm. The three adaptive concepts were: high-gain limit cycle, Liapunov-stable model tracking, and maximum likelihood estimation. Sensors were restricted to conventional inertial instruments (rate gyros and accelerometers) without use of air-data measurements. Performance, growth potential, and computer requirements were used as criteria for selecting the most promising of these candidates for further refinement. The maximum likelihood concept was selected primarily because it offers the greatest potential for identifying several aircraft parameters and hence for improved control performance in future aircraft application. In terms of identification and gain adjustment accuracy, the MLE design is slightly superior to the other two, but this has no significant effects on the control performance achievable with the F-8C aircraft. The maximum likelihood design is recommended for flight test, and several refinements to that design are proposed.

Assessment of the performance of a compact concentric spectrometer system for Atmospheric Differential Optical Absorption Spectroscopy

NASA Astrophysics Data System (ADS)

Whyte, C.; Leigh, R. J.; Lobb, D.; Williams, T.; Remedios, J. J.; Cutter, M.; Monks, P. S.

2009-12-01

A breadboard demonstrator of a novel UV/VIS grating spectrometer has been developed based upon a concentric arrangement of a spherical meniscus lens, concave spherical mirror and curved diffraction grating suitable for a range of atmospheric remote sensing applications from the ground or space. The spectrometer is compact and provides high optical efficiency and performance benefits over traditional instruments. The concentric design is capable of handling high relative apertures, owing to spherical aberration and comma being near zero at all surfaces. The design also provides correction for transverse chromatic aberration and distortion, in addition to correcting for the distortion called "smile", the curvature of the slit image formed at each wavelength. These properties render this design capable of superior spectral and spatial performance with size and weight budgets significantly lower than standard configurations. This form of spectrometer design offers the potential for exceptionally compact instrument for differential optical absorption spectroscopy (DOAS) applications from LEO, GEO, HAP or ground-based platforms. The breadboard demonstrator has been shown to offer high throughput and a stable Gaussian line shape with a spectral range from 300 to 450 nm at 0.5 nm resolution, suitable for a number of typical DOAS applications.

Operational seasonal forecasting of crop performance.

PubMed

Stone, Roger C; Meinke, Holger

2005-11-29

Integrated, interdisciplinary crop performance forecasting systems, linked with appropriate decision and discussion support tools, could substantially improve operational decision making in agricultural management. Recent developments in connecting numerical weather prediction models and general circulation models with quantitative crop growth models offer the potential for development of integrated systems that incorporate components of long-term climate change. However, operational seasonal forecasting systems have little or no value unless they are able to change key management decisions. Changed decision making through incorporation of seasonal forecasting ultimately has to demonstrate improved long-term performance of the cropping enterprise. Simulation analyses conducted on specific production scenarios are especially useful in improving decisions, particularly if this is done in conjunction with development of decision-support systems and associated facilitated discussion groups. Improved management of the overall crop production system requires an interdisciplinary approach, where climate scientists, agricultural scientists and extension specialists are intimately linked with crop production managers in the development of targeted seasonal forecast systems. The same principle applies in developing improved operational management systems for commodity trading organizations, milling companies and agricultural marketing organizations. Application of seasonal forecast systems across the whole value chain in agricultural production offers considerable benefits in improving overall operational management of agricultural production.

Operational seasonal forecasting of crop performance

PubMed Central

Stone, Roger C; Meinke, Holger

2005-01-01

Integrated, interdisciplinary crop performance forecasting systems, linked with appropriate decision and discussion support tools, could substantially improve operational decision making in agricultural management. Recent developments in connecting numerical weather prediction models and general circulation models with quantitative crop growth models offer the potential for development of integrated systems that incorporate components of long-term climate change. However, operational seasonal forecasting systems have little or no value unless they are able to change key management decisions. Changed decision making through incorporation of seasonal forecasting ultimately has to demonstrate improved long-term performance of the cropping enterprise. Simulation analyses conducted on specific production scenarios are especially useful in improving decisions, particularly if this is done in conjunction with development of decision-support systems and associated facilitated discussion groups. Improved management of the overall crop production system requires an interdisciplinary approach, where climate scientists, agricultural scientists and extension specialists are intimately linked with crop production managers in the development of targeted seasonal forecast systems. The same principle applies in developing improved operational management systems for commodity trading organizations, milling companies and agricultural marketing organizations. Application of seasonal forecast systems across the whole value chain in agricultural production offers considerable benefits in improving overall operational management of agricultural production. PMID:16433097

Propulsion and fluid management - Station keeping will eat energy on a new scale

NASA Technical Reports Server (NTRS)

Petrash, D. A.

1983-01-01

An attempt is made to identify technologies that could be brought to a state of minimal development risk in the near term, yet offer the potential for evolutionary growth consistent with future space station propulsion requirements. Prospective auxiliary propulsion propellants will be usable by other systems, thereby offering resupply benefits and a benign rather than corrosive or toxic handling environment. NASA programs are currently underway to develop the storage and supply methods for cryogenic liquids in orbit. The recovery of unused propellants from the Space Shuttle Orbiter and External Tank are being evaluated in order to define Shuttle modifications and performance penalties. Fluid management subsystem requirements and characteristics cannot, however, be fully defined until a firm mission scenario has been established and other space station subsystems are more clearly defined.

A statistical physics perspective on alignment-independent protein sequence comparison.

PubMed

Chattopadhyay, Amit K; Nasiev, Diar; Flower, Darren R

2015-08-01

Within bioinformatics, the textual alignment of amino acid sequences has long dominated the determination of similarity between proteins, with all that implies for shared structure, function and evolutionary descent. Despite the relative success of modern-day sequence alignment algorithms, so-called alignment-free approaches offer a complementary means of determining and expressing similarity, with potential benefits in certain key applications, such as regression analysis of protein structure-function studies, where alignment-base similarity has performed poorly. Here, we offer a fresh, statistical physics-based perspective focusing on the question of alignment-free comparison, in the process adapting results from 'first passage probability distribution' to summarize statistics of ensemble averaged amino acid propensity values. In this article, we introduce and elaborate this approach. © The Author 2015. Published by Oxford University Press.

Re-Assessing Green Building Performance: A Post Occupancy Evaluation of 22 GSA Buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fowler, Kimberly M.; Rauch, Emily M.; Henderson, Jordan W.

2010-06-01

2nd report on the performance of GSA's sustainably designed buildings. The purpose of this study was to provide an overview of measured whole building performance as it compares to GSA and industry baselines. The PNNL research team found the data analysis illuminated strengths and weaknesses of individual buildings as well as the portfolio of buildings. This section includes summary data, observations that cross multiple performance metrics, discussion of lessons learned from this research, and opportunities for future research. The summary of annual data for each of the performance metrics is provided in Table 25. The data represent 1 year ofmore » measurements and are not associated with any specific design features or strategies. Where available, multiple years of data were examined and there were minimal significant differences between the years. Individually focused post occupancy evaluation (POEs) would allow for more detailed analysis of the buildings. Examining building performance over multiple years could potentially offer a useful diagnostic tool for identifying building operations that are in need of operational changes. Investigating what the connection is between the building performance and the design intent would offer potential design guidance and possible insight into building operation strategies. The 'aggregate operating cost' metric used in this study represents the costs that were available for developing a comparative industry baseline for office buildings. The costs include water utilities, energy utilities, general maintenance, grounds maintenance, waste and recycling, and janitorial costs. Three of the buildings that cost more than the baseline in Figure 45 have higher maintenance costs than the baseline, and one has higher energy costs. Given the volume of data collected and analyzed for this study, the inevitable request is for a simple answer with respect to sustainably designed building performance. As previously stated, compiling the individual building values into single metrics is not statistically valid given the small number of buildings, but it has been done to provide a cursory view of this portfolio of sustainably designed buildings. For all metrics except recycling cost per rentable square foot and CBE survey response rate, the averaged building performance was better than the baseline for the GSA buildings in this study.« less

Galactic archaeology in action space

NASA Astrophysics Data System (ADS)

Sanderson, Robyn

2009-05-01

Working in action space offers an instructive alternative view of the process of hierarchical assembly in galaxies, but performing the necessary canonical transformation formally requires both complete phase space information of a stellar population and knowledge of the correct galactic potential, neither of which is generally available. I use the approximate-action method pioneered by MacMillan and Binney (2008) to examine the remnant of a late-time merger in M31, which was modeled by Fardal et al. (2007).

High Temperature Oxidation and Mechanical properties of Silicon Nitride.

DTIC Science & Technology

1980-11-30

The results of thermogravimentric studies on the rate of oxidation of chemically vapor-deposited Si3 N, at various temperatures are reported. Up to...only be such ceramics as Si3N4 -. In addition to the potential for increased engine efficiency through higher gas-inlet temperatures, the use of Si3 N...to replace cur- rently used Ni -or Co-based superalloys offers a significant weight reduction that can increase the performance of the propulsion system

Guiding dental student learning and assessing performance in critical thinking with analysis of emerging strategies.

PubMed

Johnsen, David C; Lipp, Mitchell J; Finkelstein, Michael W; Cunningham-Ford, Marsha A

2012-12-01

Patient-centered care involves an inseparable set of knowledge, abilities, and professional traits on the part of the health care provider. For practical reasons, health professions education is segmented into disciplines or domains like knowledge, technical skills, and critical thinking, and the culture of dental education is weighted toward knowledge and technical skills. Critical thinking, however, has become a growing presence in dental curricula. To guide student learning and assess performance in critical thinking, guidelines have been developed over the past several decades in the educational literature. Prominent among these guidelines are the following: engage the student in multiple situations/exercises reflecting critical thinking; for each exercise, emulate the intended activity for validity; gain agreement of faculty members across disciplines and curriculum years on the learning construct, application, and performance assessment protocol for reliability; and use the same instrument to guide learning and assess performance. The purposes of this article are 1) to offer a set of concepts from the education literature potentially helpful to guide program design or corroborate existing programs in dental education; 2) to offer an implementation model consolidating these concepts as a guide for program design and execution; 3) to cite specific examples of exercises and programs in critical thinking in the dental education literature analyzed against these concepts; and 4) to discuss opportunities and challenges in guiding student learning and assessing performance in critical thinking for dentistry.

Chip-based microtrap arrays for cold polar molecules

NASA Astrophysics Data System (ADS)

Hou, Shunyong; Wei, Bin; Deng, Lianzhong; Yin, Jianping

2017-12-01

Compared to the atomic chip, which has been a powerful platform to perform an astonishing range of applications from rapid Bose-Einstein condensate (BEC) production to the atomic clock, the molecular chip is only in its infant stages. Recently a one-dimensional electric lattice was demonstrated to trap polar molecules on a chip. This excellent work opens up the way to building a molecular chip laboratory. Here we propose a two-dimensional (2D) electric lattice on a chip with concise and robust structure, which is formed by arrays of squared gold wires. Arrays of microtraps that originate in the microsize electrodes offer a steep gradient and thus allow for confining both light and heavy polar molecules. Theoretical analysis and numerical calculations are performed using two types of sample molecules, N D3 and SrF, to justify the possibility of our proposal. The height of the minima of the potential wells is about 10 μm above the surface of the chip and can be easily adjusted in a wide range by changing the voltages applied on the electrodes. These microtraps offer intriguing perspectives for investigating cold molecules in periodic potentials, such as quantum computing science, low-dimensional physics, and some other possible applications amenable to magnetic or optical lattice. The 2D adjustable electric lattice is expected to act as a building block for a future gas-phase molecular chip laboratory.

The potential for modification in cloning and vitrification technology to enhance genetic progress in beef cattle in Northern Australia.

PubMed

Taylor-Robinson, Andrew W; Walton, Simon; Swain, David L; Walsh, Kerry B; Vajta, Gábor

2014-08-01

Recent advances in embryology and related research offer considerable possibilities to accelerate genetic improvement in cattle breeding. Such progress includes optimization and standardization of laboratory embryo production (in vitro fertilization - IVF), introduction of a highly efficient method for cryopreservation (vitrification), and dramatic improvement in the efficiency of somatic cell nuclear transfer (cloning) in terms of required effort, cost, and overall outcome. Handmade cloning (HMC), a simplified version of somatic cell nuclear transfer, offers the potential for relatively easy and low-cost production of clones. A potentially modified method of vitrification used at a centrally located laboratory facility could result in cloned offspring that are economically competitive with elite animals produced by more traditional means. Apart from routine legal and intellectual property issues, the main obstacle that hampers rapid uptake of these technologies by the beef cattle industry is a lack of confidence from scientific and commercial sources. Once stakeholder support is increased, the combined application of these methods makes a rapid advance toward desirable traits (rapid growth, high-quality beef, optimized reproductive performance) a realistic goal. The potential impact of these technologies on genetic advancement in beef cattle herds in which improvement of stock is sought, such as in northern Australia, is hard to overestimate. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Evaluating the impact of the humanities in medical education.

PubMed

Wershof Schwartz, Andrea; Abramson, Jeremy S; Wojnowich, Israel; Accordino, Robert; Ronan, Edward J; Rifkin, Mary R

2009-08-01

The inclusion of the humanities in medical education may offer significant potential benefits to individual future physicians and to the medical community as a whole. Debate remains, however, about the definition and precise role of the humanities in medical education, whether at the premedical, medical school, or postgraduate level. Recent trends have revealed an increasing presence of the humanities in medical training. This article reviews the literature on the impact of humanities education on the performance of medical students and residents and the challenges posed by the evaluation of the impact of humanities in medical education. Students who major in the humanities as college students perform just as well, if not better, than their peers with science backgrounds during medical school and in residency on objective measures of achievement such as National Board of Medical Examiners scores and academic grades. Although many humanities electives and courses are offered in premedical and medical school curricula, measuring and quantifying their impact has proven challenging because the courses are diverse in content and goals. Many of the published studies involve self-selected groups of students and seek to measure subjective outcomes which are difficult to measure, such as increases in empathy, professionalism, and self-care. Further research is needed to define the optimal role for humanities education in medical training; in particular, more quantitative studies are needed to examine the impact that it may have on physician performance beyond medical school and residency. Medical educators must consider what potential benefits humanities education can contribute to medical education, how its impact can be measured, and what ultimate outcomes we hope to achieve.

On-sky performance evaluation and calibration of a polarization-sensitive focal plane array

NASA Astrophysics Data System (ADS)

Vorobiev, Dmitry; Ninkov, Zoran; Brock, Neal; West, Ray

2016-07-01

The advent of pixelated micropolarizer arrays (MPAs) has facilitated the development of polarization-sensitive focal plane arrays (FPAs) based on charge-coupled devices (CCDs) and active pixel sensors (APSs), which are otherwise only able to measure the intensity of light. Polarization sensors based on MPAs are extremely compact, light-weight, mechanically robust devices with no moving parts, capable of measuring the degree and angle of polarization of light in a single snapshot. Furthermore, micropolarizer arrays based on wire grid polarizers (so called micro-grid polarizers) offer extremely broadband performance, across the optical and infrared regimes. These devices have potential for a wide array of commercial and research applications, where measurements of polarization can provide critical information, but where conventional polarimeters could be practically implemented. To date, the most successful commercial applications of these devices are 4D Technology's PhaseCam laser interferometers and PolarCam imaging polarimeters. Recently, MPA-based polarimeters have been identified as a potential solution for space-based telescopes, where the small size, snapshot capability and low power consumption (offered by these devices) are extremely desirable. In this work, we investigated the performance of MPA-based polarimeters designed for astronomical polarimetry using the Rochester Institute of Technology Polarization Imaging Camera (RITPIC). We deployed RITPIC on the 0.9 meter SMARTS telescope at the Cerro Tololo Inter-American Observatory and observed a variety of astronomical objects (calibration stars, variable stars, reflection nebulae and planetary nebulae). We use our observations to develop calibration procedures that are unique to these devices and provide an estimate for polarimetric precision that is achievable.

Accuracy of existing atomic potentials for the CdTe semiconductor compound

NASA Astrophysics Data System (ADS)

Ward, D. K.; Zhou, X. W.; Wong, B. M.; Doty, F. P.; Zimmerman, J. A.

2011-06-01

CdTe and CdTe-based Cd1-xZnxTe (CZT) alloys are important semiconductor compounds that are used in a variety of technologies including solar cells, radiation detectors, and medical imaging devices. Performance of such systems, however, is limited due to the propensity of nano- and micro-scale defects that form during crystal growth and manufacturing processes. Molecular dynamics simulations offer an effective approach to study the formation and interaction of atomic scale defects in these crystals, and provide insight on how to minimize their concentrations. The success of such a modeling effort relies on the accuracy and transferability of the underlying interatomic potential used in simulations. Such a potential must not only predict a correct trend of structures and energies of a variety of elemental and compound lattices, defects, and surfaces but also capture correct melting behavior and should be capable of simulating crystalline growth during vapor deposition as these processes sample a variety of local configurations. In this paper, we perform a detailed evaluation of the performance of two literature potentials for CdTe, one having the Stillinger-Weber form and the other possessing the Tersoff form. We examine simulations of structures and the corresponding energies of a variety of elemental and compound lattices, defects, and surfaces compared to those obtained from ab initio calculations and experiments. We also perform melting temperature calculations and vapor deposition simulations. Our calculations show that the Stillinger-Weber parameterization produces the correct lowest energy structure. This potential, however, is not sufficiently transferrable for defect studies. Origins of the problems of these potentials are discussed and insights leading to the development of a more transferrable potential suitable for molecular dynamics simulations of defects in CdTe crystals are provided.

3D graphics, virtual reality, and motion-onset visual evoked potentials in neurogaming.

PubMed

Beveridge, R; Wilson, S; Coyle, D

2016-01-01

A brain-computer interface (BCI) offers movement-free control of a computer application and is achieved by reading and translating the cortical activity of the brain into semantic control signals. Motion-onset visual evoked potentials (mVEP) are neural potentials employed in BCIs and occur when motion-related stimuli are attended visually. mVEP dynamics are correlated with the position and timing of the moving stimuli. To investigate the feasibility of utilizing the mVEP paradigm with video games of various graphical complexities including those of commercial quality, we conducted three studies over four separate sessions comparing the performance of classifying five mVEP responses with variations in graphical complexity and style, in-game distractions, and display parameters surrounding mVEP stimuli. To investigate the feasibility of utilizing contemporary presentation modalities in neurogaming, one of the studies compared mVEP classification performance when stimuli were presented using the oculus rift virtual reality headset. Results from 31 independent subjects were analyzed offline. The results show classification performances ranging up to 90% with variations in conditions in graphical complexity having limited effect on mVEP performance; thus, demonstrating the feasibility of using the mVEP paradigm within BCI-based neurogaming. © 2016 Elsevier B.V. All rights reserved.

Metal-Organic Heat Carrier Nanofluids

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGrail, B. Peter; Thallapally, Praveen K.; Blanchard, Jeremy

2013-09-01

Nanofluids, dispersions of metal or oxide nanoparticles in a base working fluid, are being intensively studied due to improvements they offer in thermal properties of the working fluid. However, these benefits have been erratically demonstrated and proven impacts on thermal conductivity are modest and well described from long-established effective medium theory. In this paper, we describe a new class of metal-organic heat carrier (MOHC) nanofluid that offers potential for a larger performance boost in thermal vapor-liquid compression cycles. MOHCs are nanophase porous coordination solids designed to reversibly uptake the working fluid molecules in which the MOHCs are suspended. Additional heatmore » can be extracted in a heat exchanger or solar collector from the endothermic enthalpy of desorption, which is then released as the nanofluid transits through a power generating device such as a turboexpander. Calculations for an R123 MOHC nanofluid indicated potential for up to 15% increase in power output. Capillary tube experiments show that liquid-vapor transitions occur without nanoparticle deposition on the tube walls provided entrance Reynolds number exceeds approximately 100.« less

Personal Access Satellite System (PASS) study. Fiscal year 1989 results

NASA Technical Reports Server (NTRS)

Sue, Miles K. (Editor)

1990-01-01

The Jet Propulsion Laboratory is exploring the potential and feasibility of a personal access satellite system (PASS) that will offer the user greater freedom and mobility than existing or currently planned communications systems. Studies performed in prior years resulted in a strawman design and the identification of technologies that are critical to the successful implementation of PASS. The study efforts in FY-89 were directed towards alternative design options with the objective of either improving the system performance or alleviating the constraints on the user terminal. The various design options and system issues studied this year and the results of the study are presented.

Astrobee: Developing a Free Flying Robot for the International Space Station

NASA Technical Reports Server (NTRS)

Bualat, Maria; Barlow, Jonathan; Fong, Terrence; Provencher, Christopher; Smith, Trey; Zuniga, Allison

2015-01-01

Astronaut time will always be in short supply, consumables (e.g., oxygen) will always be limited, and some work will not be feasible, or productive, for astronauts to do manually. Free flyers offer significant potential to perform a great variety of tasks, include routine, repetitive or simple but long-duration work, such as conducting environment surveys, taking sensor readings or monitoring crew activities. The "Astrobee" project is developing a new free flying robot system suitable for performing Intravehicular Activity (IVA) work on the International Space Station (ISS). This paper will describe the Astrobee project objectives, initial design, concept of operations, and key challenges.

Solar thermal upper stage: Economic advantage and development status

NASA Technical Reports Server (NTRS)

Adams, Alan M.

1995-01-01

A solar thermal upper stage (STUS) is envisioned as a propulsive concept for the future. The STUS will be used for low Earth orbit (LEO) to geostationary-Earth orbit (GEO) transfer and for planetary exploration missions. The STUS offers significant performance gains over conventional chemical propulsion systems. These performance gains translate into a more economical, more efficient method of placing useful payloads in space and maximizing the benefits derived from space activity. This paper will discuss the economical advantages of an STUS compared to conventional chemical propulsion systems, the potential market for an STUS, and the recent activity in the development of an STUS. The results of this assessment combined with the performance gains, will provide a strong justification for the development of an STUS.

Feasibility Study of Economics and Performance of Solar Photovoltaics at Massachusetts Military Reservation. A Study Prepared in Partnership with the Environmental Protection Agency for the RE-Powering America's Land Initiative: Siting Renewable Energy on Potentially Contaminated Land and Mine Sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stafford, B.; Robichaud, R.; Mosey, G.

2011-07-01

This report presents the results of an assessment of the technical and economic feasibility of deploying photovoltaics (PV) systems on a superfund site located within the Massachusetts Military Reservation (MMR). The site was assessed for possible PV installations. The cost, performance, and site impacts of different PV options were estimated. The economics of the potential systems were analyzed using an electric rate of $0.17/kWh and incentives offered in the State of Massachusetts, such as the solar renewable energy credits. According to calculations, MMR can place 8 MW of ballast-weighted, ground-mounted PV systems on the crowns of the three landfill capsmore » and the borrow pit with the PV modules tilted at 30 degrees.« less

Behavior of the potential-induced degradation of photovoltaic modules fabricated using flat mono-crystalline silicon cells with different surface orientations

NASA Astrophysics Data System (ADS)

Yamaguchi, Seira; Masuda, Atsushi; Ohdaira, Keisuke

2016-04-01

This paper deals with the dependence of the potential-induced degradation (PID) of flat, p-type mono-crystalline silicon solar cell modules on the surface orientation of solar cells. The investigated modules were fabricated from p-type mono-crystalline silicon cells with a (100) or (111) surface orientation using a module laminator. PID tests were performed by applying a voltage of -1000 V to shorted module interconnector ribbons with respect to an Al plate placed on the cover glass of the modules at 85 °C. A decrease in the parallel resistance of the (100)-oriented cell modules is more significant than that of the (111)-oriented cell modules. Hence, the performance of the (100)-oriented-cell modules drastically deteriorates, compared with that of the (111)-oriented-cell modules. This implies that (111)-oriented cells offer a higher PID resistance.

Accountable Care Organizations: The National Landscape.

PubMed

Shortell, Stephen M; Colla, Carrie H; Lewis, Valerie A; Fisher, Elliott; Kessell, Eric; Ramsay, Patricia

2015-08-01

There are now more than seven hundred accountable care organizations (ACOs) in the United States. This article describes some of their most salient characteristics including the number and types of contracts involved, organizational structures, the scope of services offered, care management capabilities, and the development of a three-category taxonomy that can be used to target technical assistance efforts and to examine performance. The current evidence on the performance of ACOs is reviewed. Since California has the largest number of ACOs (N=67) and a history of providing care under risk-bearing contracts, some additional assessments of quality and patient experience are made between California ACOs and non-ACO provider organizations. Six key issues likely to affect future ACO growth and development are discussed, and some potential "diagnostic" indicators for assessing the likelihood of potential antitrust violations are presented. Copyright © 2015 by Duke University Press.

Optical fiber sensors and signal processing for intelligent structure monitoring

NASA Technical Reports Server (NTRS)

Rogowski, Robert; Claus, R. O.; Lindner, D. K.; Thomas, Daniel; Cox, Dave

1988-01-01

The analytic and experimental performance of optical fiber sensors for the control of vibration of large aerospace and other structures are investigated. In particular, model domain optical fiber sensor systems, are being studied due to their apparent potential as distributed, low mass sensors of vibration over appropriate ranges of both low frequency and low amplitude displacements. Progress during the past three months is outlined. Progress since September is divided into work in the areas of experimental hardware development, analytical analysis, control design and sensor development. During the next six months, tests of a prototype closed-loop control system for a beam are planned which will demonstrate the solution of several optical fiber instrumentation device problems, the performance of the control system theory which incorporates the model of the modal domain sensor, and the potential for distributed control which this sensor approach offers.

The Flexible Fairness: Equality, Earned Entitlement, and Self-Interest

PubMed Central

Gu, Ruolei; Broster, Lucas S.; Shen, Xueyi; Tian, Tengxiang; Luo, Yue-Jia; Krueger, Frank

2013-01-01

The current study explored whether earned entitlement modulated the perception of fairness in three experiments. A preliminary resource earning task was added before players decided how to allocate the resource they jointly earned. Participants’ decision in allocation, their responses to equal or unequal offers, whether advantageous or disadvantageous, and subjective ratings of fairness were all assessed in the current study. Behavioral results revealed that participants proposed more generous offers and showed enhanced tolerance to disadvantageous unequal offers from others when they performed worse than their presumed “partners,” while the reverse was true in the better-performance condition. The subjective ratings also indicated the effect of earned entitlement, such that worse performance was associated with higher perceived feelings of fairness for disadvantageous unequal offers, while better performance was associated with higher feelings of fairness for advantageous unequal offers. Equal offers were considered “fair” only when earned entitlement was even between two parties. In sum, the perception of fairness is modulated by an integration of egalitarian motivation and entitlement. In addition to justice principles, participants were also motivated by self-interest, such that participants placed more weight on entitlement in the better-performance condition than in the worse-performance condition. These results imply that earned entitlement is evaluated in a self-serving way. PMID:24039867

Novel bifunctional cap for simultaneous electroencephalography and transcranial electrical stimulation.

PubMed

Wunder, Sophia; Hunold, Alexander; Fiedler, Patrique; Schlegelmilch, Falk; Schellhorn, Klaus; Haueisen, Jens

2018-05-08

Neuromodulation induced by transcranial electric stimulation (TES) exhibited promising potential for clinical practice. However, the underlying mechanisms remain subject of research. The combination of TES and electroencephalography (EEG) offers great potential for investigating these mechanisms and brain function in general, especially when performed simultaneously. In conventional applications, the combination of EEG and TES suffers from limitations on the electrode level (gel for electrode-skin interface) and the usability level (preparation time, reproducibility of positioning). To overcome these limitations, we designed a bifunctional cap for simultaneous TES-EEG applications. We used novel electrode materials, namely textile stimulation electrodes and dry EEG electrodes integrated in a flexible textile cap. We verified the functionality of this cap by analysing the effect of TES on visual evoked potentials (VEPs). In accordance with previous reports using standard TES, the amplitude of the N75 component was significantly decreased post-stimulation, indicating the feasibility of using this novel flexible cap for simultaneous TES and EEG. Further, we found a significant reduction of the P100 component only during TES, indicating a different brain modulation effect during and after TES. In conclusion, the novel bifunctional cap offers a novel tool for simultaneous TES-EEG applications in clinical research, therapy monitoring and closed-loop stimulation.

Listening and Learning in a Master Class

ERIC Educational Resources Information Center

Hanken, Ingrid Maria

2015-01-01

Most higher education institutions offering programmes in music performance organise master classes for their students. It is commonly agreed that master classes offer valuable learning opportunities for the students performing, but what do they offer for students in the audience? In this article, theories of learning by observation as well as…

Real-time monitoring through the use of technology to enhance performances throughout HIV cascades.

PubMed

Avery, Matthew; Mills, Stephen J; Stephan, Eric

2017-09-01

Controlling the HIV epidemic requires strong linkages across a 'cascade' of prevention, testing, and treatment services. Information and communications technology (ICT) offers the potential to monitor and improve the performance of this HIV cascade in real time. We assessed recent (<18 months) peer-reviewed publications regarding uses of ICT to improve performance through expanded and targeted reach, improved clinical service delivery, and reduced loss to follow-up. Research on ICT has tended to focus on a specific 'silo' of the HIV cascade rather than on tracking individuals or program performance across the cascade. Numerous innovations have been described, including use of social media to expand reach and improve programmatic targeting; technology in healthcare settings to strengthen coordination, guide clinical decision-making and improve clinical interactions; and telephone-based follow-up to improve treatment retention and adherence. With exceptions, publications have tended to be descriptive rather than evaluative, and the evidence-base for the effectiveness of ICT-driven interventions remains mixed. There is widespread recognition of the potential for ICT to improve HIV cascade performance, but with significant challenges. Successful implementation of real-time cascade monitoring will depend upon stakeholder engagement, compatibility with existing workflows, appropriate resource allocation, and managing expectations.

The impact of extensive green roofs on the improvement of thermal performance for urban areas in Mediterranean climate with reference to the city of Jijel in Algeria

NASA Astrophysics Data System (ADS)

Lehtihet, M. C.; Bouchair, A.

2018-05-01

Buildings with dark surfaces, concrete and pavement, needed for the expansion of cities, absorb huge amounts of heat, increasing the mean radiant temperatures of urban areas and offer significant potential for urban heat island (UHI) effect. The purpose of this work is to investigate the impact of green roofs on the improvement of urban heat performance in Mediterranean climate. A field investigation is carried out using two large-scale modules built in the city of Jijel in the north of Algeria. The first is a bare reinforced concrete slab whereas the second is covered with ivy plants. The experimental site, the air and surface temperature parameters and the various measurement points at the level of the modules are chosen. Measurements are performed using thermo-hygrometer, surface sensors and data acquisition apparatus. The results show that green roofs can be a potential mean of improving the thermal performance of the surrounding microclimate and energy performance of buildings in an urban area. The green roof could be an encouraging strategy against urban heat island effect not only for Mediterranean cities but also for other areas.

Improving cerebellar segmentation with statistical fusion

NASA Astrophysics Data System (ADS)

Plassard, Andrew J.; Yang, Zhen; Prince, Jerry L.; Claassen, Daniel O.; Landman, Bennett A.

2016-03-01

The cerebellum is a somatotopically organized central component of the central nervous system well known to be involved with motor coordination and increasingly recognized roles in cognition and planning. Recent work in multiatlas labeling has created methods that offer the potential for fully automated 3-D parcellation of the cerebellar lobules and vermis (which are organizationally equivalent to cortical gray matter areas). This work explores the trade offs of using different statistical fusion techniques and post hoc optimizations in two datasets with distinct imaging protocols. We offer a novel fusion technique by extending the ideas of the Selective and Iterative Method for Performance Level Estimation (SIMPLE) to a patch-based performance model. We demonstrate the effectiveness of our algorithm, Non- Local SIMPLE, for segmentation of a mixed population of healthy subjects and patients with severe cerebellar anatomy. Under the first imaging protocol, we show that Non-Local SIMPLE outperforms previous gold-standard segmentation techniques. In the second imaging protocol, we show that Non-Local SIMPLE outperforms previous gold standard techniques but is outperformed by a non-locally weighted vote with the deeper population of atlases available. This work advances the state of the art in open source cerebellar segmentation algorithms and offers the opportunity for routinely including cerebellar segmentation in magnetic resonance imaging studies that acquire whole brain T1-weighted volumes with approximately 1 mm isotropic resolution.

Development of a data-mining algorithm to identify ages at reproductive milestones in electronic medical records.

PubMed

Malinowski, Jennifer; Farber-Eger, Eric; Crawford, Dana C

2014-01-01

Electronic medical records (EMRs) are becoming more widely implemented following directives from the federal government and incentives for supplemental reimbursements for Medicare and Medicaid claims. Replete with rich phenotypic data, EMRs offer a unique opportunity for clinicians and researchers to identify potential research cohorts and perform epidemiologic studies. Notable limitations to the traditional epidemiologic study include cost, time to complete the study, and limited ancestral diversity; EMR-based epidemiologic studies offer an alternative. The Epidemiologic Architecture for Genes Linked to Environment (EAGLE) Study, as part of the Population Architecture using Genomics and Epidemiology (PAGE) I Study, has genotyped more than 15,000 patients of diverse ancestry in BioVU, the Vanderbilt University Medical Center's biorepository linked to the EMR (EAGLE BioVU). We report here the development and performance of data-mining techniques used to identify the age at menarche (AM) and age at menopause (AAM), important milestones in the reproductive lifespan, in women from EAGLE BioVU for genetic association studies. In addition, we demonstrate the ability to discriminate age at naturally-occurring menopause (ANM) from medically-induced menopause. Unusual timing of these events may indicate underlying pathologies and increased risk for some complex diseases and cancer; however, they are not consistently recorded in the EMR. Our algorithm offers a mechanism by which to extract these data for clinical and research goals.

Martini straight: Boosting performance using a shorter cutoff and GPUs

NASA Astrophysics Data System (ADS)

de Jong, Djurre H.; Baoukina, Svetlana; Ingólfsson, Helgi I.; Marrink, Siewert J.

2016-02-01

In molecular dynamics simulations, sufficient sampling is of key importance and a continuous challenge in the field. The coarse grain Martini force field has been widely used to enhance sampling. In its original implementation, this force field applied a shifted Lennard-Jones potential for the non-bonded van der Waals interactions, to avoid problems related to a relatively short cutoff. Here we investigate the use of a straight cutoff Lennard-Jones potential with potential modifiers. Together with a Verlet neighbor search algorithm, the modified potential allows the use of GPUs to accelerate the computations in Gromacs. We find that this alternative potential has little influence on most of the properties studied, including partitioning free energies, bulk liquid properties and bilayer properties. At the same time, energy conservation is kept within reasonable bounds. We conclude that the newly proposed straight cutoff approach is a viable alternative to the standard shifted potentials used in Martini, offering significant speedup even in the absence of GPUs.

Space flight nutrition research: platforms and analogs

NASA Technical Reports Server (NTRS)

Smith, Scott M.; Uchakin, Peter N.; Tobin, Brian W.

2002-01-01

Conducting research during actual or simulated weightlessness is a challenging endeavor, where even the simplest activities may present significant challenges. This article reviews some of the potential obstacles associated with performing research during space flight and offers brief descriptions of current and previous space research platforms and ground-based analogs, including those for human, animal, and cell-based research. This review is intended to highlight the main issues of space flight research analogs and leave the specifics for each physiologic system for the other papers in this section.

Aluminum plasmonic metamaterials for structural color printing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Fei; Gao, Jie; Stan, Liliana

2015-01-01

We report a structural color printing platform based on aluminum plasmonic metamaterials supporting near perfect light absorption and narrow-band spectral response tunable across the visible spectrum to realize high-resolution, angle-insensitive color printing with high color purity and saturation. Additionally, the fabricated metamaterials can be protected by a transparent polymer thin layer for ambient use with further improved color performance. The demonstrated structural color printing with aluminum plasmonic metamaterials offers great potential for relevant applications such as security marking and information storage.

Composite Structural Materials

NASA Technical Reports Server (NTRS)

Ansell, G. S.; Loewy, R. G.; Wiberly, S. E.

1984-01-01

The development and application of filamentary composite materials, is considered. Such interest is based on the possibility of using relatively brittle materials with high modulus, high strength, but low density in composites with good durability and high tolerance to damage. Fiber reinforced composite materials of this kind offer substantially improved performance and potentially lower costs for aerospace hardware. Much progress has been made since the initial developments in the mid 1960's. There were only limited applied to the primary structure of operational vehicles, mainly as aircrafts.

Mid infra-red hyper-spectral imaging with bright super continuum source and fast acousto-optic tuneable filter for cytological applications.

NASA Astrophysics Data System (ADS)

Farries, Mark; Ward, Jon; Valle, Stefano; Stephens, Gary; Moselund, Peter; van der Zanden, Koen; Napier, Bruce

2015-06-01

Mid-IR imaging spectroscopy has the potential to offer an effective tool for early cancer diagnosis. Current development of bright super-continuum sources, narrow band acousto-optic tunable filters and fast cameras have made feasible a system that can be used for fast diagnosis of cancer in vivo at point of care. The performance of a proto system that has been developed under the Minerva project is described.

Aluminum plasmonic metamaterials for structural color printing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Fei; Gao, Jie; Stan, Liliana

2015-05-26

We report a structural color printing platform based on aluminum plasmonic metamaterials supporting near perfect light absorption and narrow-band spectral response tunable across the visible spectrum to realize high-resolution, angle-insensitive color printing with high color purity and saturation. Additionally, the fabricated metamaterials can be protected by a transparent polymer thin layer for ambient use with further improved color performance. The demonstrated structural color printing with aluminum plasmonic metamaterials offers great potential for relevant applications such as security marking and information storage.

Low cost damage tolerant composite fabrication

NASA Technical Reports Server (NTRS)

Palmer, R. J.; Freeman, W. T.

1988-01-01

The resin transfer molding (RTM) process applied to composite aircraft parts offers the potential for using low cost resin systems with dry graphite fabrics that can be significantly less expensive than prepreg tape fabricated components. Stitched graphite fabric composites have demonstrated compression after impact failure performance that equals or exceeds that of thermoplastic or tough thermoset matrix composites. This paper reviews methods developed to fabricate complex shape composite parts using stitched graphite fabrics to increase damage tolerance with RTM processes to reduce fabrication cost.

(DURIP 09) Ultrafast Laser System for Coherent Anti-Stokes Raman Scattering Measurements at Data Rates of 5 kHz

DTIC Science & Technology

2010-08-22

tunable beam that will be used for the pump radiation in the femtosecond coherent anti-Stokes Raman scattering ( CARS ) measurements. This system has been...beam that will be used for the pump radiation in the femtosecond coherent anti-Stokes Raman scattering ( CARS ) measurements. This system has been... CARS ) spectroscopy. Fs CARS offers some significant potential advantages compared with nanosecond (ns) CARS , i.e., CARS as usually performed with ns

Recent Advances in Fiber Lasers for Nonlinear Microscopy

PubMed Central

Xu, C.; Wise, F. W.

2013-01-01

Nonlinear microscopy techniques developed over the past two decades have provided dramatic new capabilities for biological imaging. The initial demonstrations of nonlinear microscopies coincided with the development of solid-state femtosecond lasers, which continue to dominate applications of nonlinear microscopy. Fiber lasers offer attractive features for biological and biomedical imaging, and recent advances are leading to high-performance sources with the potential for robust, inexpensive, integrated instruments. This article discusses recent advances, and identifies challenges and opportunities for fiber lasers in nonlinear bioimaging. PMID:24416074

American Academy of Pediatrics: Children, adolescents, and television.

PubMed

2001-02-01

This statement describes the possible negative health effects of television viewing on children and adolescents, such as violent or aggressive behavior, substance use, sexual activity, obesity, poor body image, and decreased school performance. In addition to the television ratings system and the v-chip (electronic device to block programming), media education is an effective approach to mitigating these potential problems. The American Academy of Pediatrics offers a list of recommendations on this issue for pediatricians and for parents, the federal government, and the entertainment industry.

Titanium fasteners. [for aircraft industry

NASA Technical Reports Server (NTRS)

Phillips, J. L.

1972-01-01

Titanium fasteners are used in large quantities throughout the aircraft industry. Most of this usage is in aluminum structure; where titanium structure exists, titanium fasteners are logically used as well. Titanium fasteners offer potential weight savings to the designer at a cost of approximately $30 per pound of weight saved. Proper and least cost usage must take into consideration type of fastener per application, galvanic couples and installation characteristics of protective coatings, cosmetic appearance, paint adhesion, installation forces and methods available and fatigue performance required.

Highly Crystalline C8-BTBT Thin-Film Transistors by Lateral Homo-Epitaxial Growth on Printed Templates.

PubMed

Janneck, Robby; Pilet, Nicolas; Bommanaboyena, Satya Prakash; Watts, Benjamin; Heremans, Paul; Genoe, Jan; Rolin, Cedric

2017-11-01

Highly crystalline thin films of organic semiconductors offer great potential for fundamental material studies as well as for realizing high-performance, low-cost flexible electronics. The fabrication of these films directly on inert substrates is typically done by meniscus-guided coating techniques. The resulting layers show morphological defects that hinder charge transport and induce large device-to-device variability. Here, a double-step method for organic semiconductor layers combining a solution-processed templating layer and a lateral homo-epitaxial growth by a thermal evaporation step is reported. The epitaxial regrowth repairs most of the morphological defects inherent to meniscus-guided coatings. The resulting film is highly crystalline and features a mobility increased by a factor of three and a relative spread in device characteristics improved by almost half an order of magnitude. This method is easily adaptable to other coating techniques and offers a route toward the fabrication of high-performance, large-area electronics based on highly crystalline thin films of organic semiconductors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigation of spatial resolution and temporal performance of SAPHIRE (scintillator avalanche photoconductor with high resolution emitter readout) with integrated electrostatic focusing

NASA Astrophysics Data System (ADS)

Scaduto, David A.; Lubinsky, Anthony R.; Rowlands, John A.; Kenmotsu, Hidenori; Nishimoto, Norihito; Nishino, Takeshi; Tanioka, Kenkichi; Zhao, Wei

2014-03-01

We have previously proposed SAPHIRE (scintillator avalanche photoconductor with high resolution emitter readout), a novel detector concept with potentially superior spatial resolution and low-dose performance compared with existing flat-panel imagers. The detector comprises a scintillator that is optically coupled to an amorphous selenium photoconductor operated with avalanche gain, known as high-gain avalanche rushing photoconductor (HARP). High resolution electron beam readout is achieved using a field emitter array (FEA). This combination of avalanche gain, allowing for very low-dose imaging, and electron emitter readout, providing high spatial resolution, offers potentially superior image quality compared with existing flat-panel imagers, with specific applications to fluoroscopy and breast imaging. Through the present collaboration, a prototype HARP sensor with integrated electrostatic focusing and nano- Spindt FEA readout technology has been fabricated. The integrated electron-optic focusing approach is more suitable for fabricating large-area detectors. We investigate the dependence of spatial resolution on sensor structure and operating conditions, and compare the performance of electrostatic focusing with previous technologies. Our results show a clear dependence of spatial resolution on electrostatic focusing potential, with performance approaching that of the previous design with external mesh-electrode. Further, temporal performance (lag) of the detector is evaluated and the results show that the integrated electrostatic focusing design exhibits comparable or better performance compared with the mesh-electrode design. This study represents the first technical evaluation and characterization of the SAPHIRE concept with integrated electrostatic focusing.

On noise and the performance benefit of nonblocking collectives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Widener, Patrick M.; Levy, Scott; Ferreira, Kurt B.

Relaxed synchronization offers the potential of maintaining application scalability by allowing many processes to make independent progress when some processes suffer delays. Yet, the benefits of this approach in important parallel workloads have not been investigated in detail. In this paper, we use a validated simulation approach to explore the noise mitigation effects of idealized nonblocking collectives in workloads where these collectives are a major contributor to total execution time. In conclusion, although nonblocking collectives are unlikely to provide significant noise mitigation to applications in the low-OS-noise environments expected in next-generation HPC systems, we show that they can potentially improvemore » application runtime with respect to other noise types.« less

Direct patterning of organic conductors on knitted textiles for long-term electrocardiography

PubMed Central

Takamatsu, Seiichi; Lonjaret, Thomas; Crisp, Dakota; Badier, Jean-Michel; Malliaras, George G.; Ismailova, Esma

2015-01-01

Wearable sensors are receiving a great deal of attention as they offer the potential to become a key technological tool for healthcare. In order for this potential to come to fruition, new electroactive materials endowing high performance need to be integrated with textiles. Here we present a simple and reliable technique that allows the patterning of conducting polymers on textiles. Electrodes fabricated using this technique showed a low impedance contact with human skin, were able to record high quality electrocardiograms at rest, and determine heart rate even when the wearer was in motion. This work paves the way towards imperceptible electrophysiology sensors for human health monitoring. PMID:26446346

On noise and the performance benefit of nonblocking collectives

DOE PAGES

Widener, Patrick M.; Levy, Scott; Ferreira, Kurt B.; ...

2015-11-02

Relaxed synchronization offers the potential of maintaining application scalability by allowing many processes to make independent progress when some processes suffer delays. Yet, the benefits of this approach in important parallel workloads have not been investigated in detail. In this paper, we use a validated simulation approach to explore the noise mitigation effects of idealized nonblocking collectives in workloads where these collectives are a major contributor to total execution time. In conclusion, although nonblocking collectives are unlikely to provide significant noise mitigation to applications in the low-OS-noise environments expected in next-generation HPC systems, we show that they can potentially improvemore » application runtime with respect to other noise types.« less

The use of hydrogen for aircraft propulsion in view of the fuel crisis.

NASA Technical Reports Server (NTRS)

Weiss, S.

1973-01-01

In view of projected decreases in available petroleum fuels, interest has been generated in exploiting the potential of liquid hydrogen (LH2) as an aircraft fuel. Cost studies of LH2 production show it to be more expensive than presently used fuels. Regardless of cost considerations, LH2 is viewed as an attractive aircraft fuel because of the potential performance benefits it offers. Accompanying these benefits, however, are many new problems associated with aircraft design and operations; for example, problems related to fuel system design and the handling of LH2 during ground servicing. Some of the factors influencing LH2 fuel tank design, pumping, heat exchange, and flow regulation are discussed.

High education may offer protection against tauopathy in patients with mild cognitive impairment.

PubMed

Rolstad, Sindre; Nordlund, Arto; Eckerström, Carl; Gustavsson, Marie H; Blennow, Kaj; Olesen, Pernille J; Zetterberg, Henrik; Wallin, Anders

2010-01-01

The concepts of brain and cognitive reserve stem from the observation that premorbid factors (e.g., education) result in variation in the response to brain pathology. Potential early influence of reserve on pathology, as assessed using the cerebrospinal fluid biomarkers total tau (t-tau) and amyloid-beta42, and cognition was explored in mild cognitive impairment (MCI) patients who remained stable over a two-year period. A total of 102 patients with stable MCI grouped on the basis of educational level were compared with regard to biomarker concentrations and cognitive performance. Stable MCI patients with higher education had lower concentrations of t-tau as compared to those with lower education. Also, educational level predicted a significant proportion of the total variance in t-tau concentrations. Our results suggest that higher education may offer protection against tauopathy.

Continuous-wave terahertz imaging of nonmelanoma skin cancers

NASA Astrophysics Data System (ADS)

Joseph, Cecil Sudhir

Continuous wave terahertz imaging has the potential to offer a safe, non-invasive medical imaging modality for detecting different types of human skin cancers. Terahertz pulse imaging (TPI) has already shown that there is contrast between basal cell carcinoma and normal skin. Continuous-wave imaging offers a simpler, lower cost alternative to terahertz pulse imaging. This project aims to isolate the optimal contrast frequency for a continuous wave terahertz imaging system and demonstrate transmission based, in-vitro , imaging of thin sections of non-melanoma skin cancers and correlate the images to sample histology. The aim of this project is to conduct a proof-of-principle experiment that establishes whether continuous-wave terahertz imaging can detect differences between cancerous and normal tissue while outlining the basic requirements for building a system capable of performing in vivo tests.

Modeling and evaluating the performance of Brillouin distributed optical fiber sensors.

PubMed

Soto, Marcelo A; Thévenaz, Luc

2013-12-16

A thorough analysis of the key factors impacting on the performance of Brillouin distributed optical fiber sensors is presented. An analytical expression is derived to estimate the error on the determination of the Brillouin peak gain frequency, based for the first time on real experimental conditions. This expression is experimentally validated, and describes how this frequency uncertainty depends on measurement parameters, such as Brillouin gain linewidth, frequency scanning step and signal-to-noise ratio. Based on the model leading to this expression and considering the limitations imposed by nonlinear effects and pump depletion, a figure-of-merit is proposed to fairly compare the performance of Brillouin distributed sensing systems. This figure-of-merit offers to the research community and to potential users the possibility to evaluate with an objective metric the real performance gain resulting from any proposed configuration.

NREL Evaluates Performance of Fast-Charge Electric Buses

DOE Office of Scientific and Technical Information (OSTI.GOV)

2016-09-16

This real-world performance evaluation is designed to enhance understanding of the overall usage and effectiveness of electric buses in transit operation and to provide unbiased technical information to other agencies interested in adding such vehicles to their fleets. Initial results indicate that the electric buses under study offer significant fuel and emissions savings. The final results will help Foothill Transit optimize the energy-saving potential of its transit fleet. NREL's performance evaluations help vehicle manufacturers fine-tune their designs and help fleet managers select fuel-efficient, low-emission vehicles that meet their bottom line and operational goals. help Foothill Transit optimize the energy-saving potentialmore » of its transit fleet. NREL's performance evaluations help vehicle manufacturers fine-tune their designs and help fleet managers select fuel-efficient, low-emission vehicles that meet their bottom line and operational goals.« less

The use of digital PCR to improve the application of quantitative molecular diagnostic methods for tuberculosis.

PubMed

Devonshire, Alison S; O'Sullivan, Denise M; Honeyborne, Isobella; Jones, Gerwyn; Karczmarczyk, Maria; Pavšič, Jernej; Gutteridge, Alice; Milavec, Mojca; Mendoza, Pablo; Schimmel, Heinz; Van Heuverswyn, Fran; Gorton, Rebecca; Cirillo, Daniela Maria; Borroni, Emanuele; Harris, Kathryn; Barnard, Marinus; Heydenrych, Anthenette; Ndusilo, Norah; Wallis, Carole L; Pillay, Keshree; Barry, Thomas; Reddington, Kate; Richter, Elvira; Mozioğlu, Erkan; Akyürek, Sema; Yalçınkaya, Burhanettin; Akgoz, Muslum; Žel, Jana; Foy, Carole A; McHugh, Timothy D; Huggett, Jim F

2016-08-03

Real-time PCR (qPCR) based methods, such as the Xpert MTB/RIF, are increasingly being used to diagnose tuberculosis (TB). While qualitative methods are adequate for diagnosis, the therapeutic monitoring of TB patients requires quantitative methods currently performed using smear microscopy. The potential use of quantitative molecular measurements for therapeutic monitoring has been investigated but findings have been variable and inconclusive. The lack of an adequate reference method and reference materials is a barrier to understanding the source of such disagreement. Digital PCR (dPCR) offers the potential for an accurate method for quantification of specific DNA sequences in reference materials which can be used to evaluate quantitative molecular methods for TB treatment monitoring. To assess a novel approach for the development of quality assurance materials we used dPCR to quantify specific DNA sequences in a range of prototype reference materials and evaluated accuracy between different laboratories and instruments. The materials were then also used to evaluate the quantitative performance of qPCR and Xpert MTB/RIF in eight clinical testing laboratories. dPCR was found to provide results in good agreement with the other methods tested and to be highly reproducible between laboratories without calibration even when using different instruments. When the reference materials were analysed with qPCR and Xpert MTB/RIF by clinical laboratories, all laboratories were able to correctly rank the reference materials according to concentration, however there was a marked difference in the measured magnitude. TB is a disease where the quantification of the pathogen could lead to better patient management and qPCR methods offer the potential to rapidly perform such analysis. However, our findings suggest that when precisely characterised materials are used to evaluate qPCR methods, the measurement result variation is too high to determine whether molecular quantification of Mycobacterium tuberculosis would provide a clinically useful readout. The methods described in this study provide a means by which the technical performance of quantitative molecular methods can be evaluated independently of clinical variability to improve accuracy of measurement results. These will assist in ultimately increasing the likelihood that such approaches could be used to improve patient management of TB.

Robust Exploration and Commercial Missions to the Moon Using NTR LANTR Propulsion and Lunar-Derived Propellants

NASA Technical Reports Server (NTRS)

Borowski, Stanley K.; Ryan, Stephen W.; Burke, Laura M.; McCurdy, David R.; Fittje, James E.; Joyner, Claude R.

2017-01-01

NASAs current focus is on the Journey to Mars sometime around the mid-to-late 2030s. However, it is also supporting the development of commercial cargo and crew delivery to the ISS (e.g., SpaceX, Orbital Sciences, SNC, Boeing) where inflatable habitation technology (e.g., Bigelow Aerospaces BEAM) is currently being tested Significant private sector interest in commercial lunar activities has also been expressed by Bigelow Aerospace, Golden Spike Company, Shackleton Energy Company (SEC), and most recently by United Launch Alliance (ULA) in their Cislunar-1000 plan Lunar-derived propellant (LDP) production specifically LLO2 and LLH2 offers significant mission leverage and are central themes of both SECs and ULAs plans for commercial lunar development. An efficient, proven propulsion technology with reuse capability like NTP offers the potential for affordable access through space essential to realizing commercial lunar missions.This presentation examines the performance potential of an evolutionary lunar transportation system (LTS) architecture using NTR initially, then transitioning to LANTR as LDPs(e.g., LLO2 from regolith or volcanic glass, LLO2 and LLH2 from lunar polar ice deposits) become available in lunar orbit (LO) Mission applications range from cargo delivery, to crewed landing, to routine commuter flights to and from transportation system nodes located in both lunar equatorial and lunar polar orbits. This presentation examines the performance potential of an evolutionary lunar transportation system (LTS) architecture using NTR initially, then transitioning to LANTR as LDPs (e.g., LLO2 from regolith or volcanic glass, LLO2 and LLH2 from lunar polar ice deposits) become available in lunar orbit (LO) Mission applications range from cargo delivery, to crewed landing, to routine commuter flights to and from transportation system nodes located in both lunar equatorial and lunar polar orbits.

Towards a Low-Cost Real-Time Photogrammetric Landslide Monitoring System Utilising Mobile and Cloud Computing Technology

NASA Astrophysics Data System (ADS)

Chidburee, P.; Mills, J. P.; Miller, P. E.; Fieber, K. D.

2016-06-01

Close-range photogrammetric techniques offer a potentially low-cost approach in terms of implementation and operation for initial assessment and monitoring of landslide processes over small areas. In particular, the Structure-from-Motion (SfM) pipeline is now extensively used to help overcome many constraints of traditional digital photogrammetry, offering increased user-friendliness to nonexperts, as well as lower costs. However, a landslide monitoring approach based on the SfM technique also presents some potential drawbacks due to the difficulty in managing and processing a large volume of data in real-time. This research addresses the aforementioned issues by attempting to combine a mobile device with cloud computing technology to develop a photogrammetric measurement solution as part of a monitoring system for landslide hazard analysis. The research presented here focusses on (i) the development of an Android mobile application; (ii) the implementation of SfM-based open-source software in the Amazon cloud computing web service, and (iii) performance assessment through a simulated environment using data collected at a recognized landslide test site in North Yorkshire, UK. Whilst the landslide monitoring mobile application is under development, this paper describes experiments carried out to ensure effective performance of the system in the future. Investigations presented here describe the initial assessment of a cloud-implemented approach, which is developed around the well-known VisualSFM algorithm. Results are compared to point clouds obtained from alternative SfM 3D reconstruction approaches considering a commercial software solution (Agisoft PhotoScan) and a web-based system (Autodesk 123D Catch). Investigations demonstrate that the cloud-based photogrammetric measurement system is capable of providing results of centimeter-level accuracy, evidencing its potential to provide an effective approach for quantifying and analyzing landslide hazard at a local-scale.

GaSb thermophotovoltaic cells grown on GaAs by molecular beam epitaxy using interfacial misfit arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Juang, Bor-Chau, E-mail: bcjuang@ucla.edu; Laghumavarapu, Ramesh B.; Foggo, Brandon J.

There exists a long-term need for foreign substrates on which to grow GaSb-based optoelectronic devices. We address this need by using interfacial misfit arrays to grow GaSb-based thermophotovoltaic cells directly on GaAs (001) substrates and demonstrate promising performance. We compare these cells to control devices grown on GaSb substrates to assess device properties and material quality. The room temperature dark current densities show similar characteristics for both cells on GaAs and on GaSb. Under solar simulation the cells on GaAs exhibit an open-circuit voltage of 0.121 V and a short-circuit current density of 15.5 mA/cm{sup 2}. In addition, the cells on GaAsmore » substrates maintain 10% difference in spectral response to those of the control cells over a large range of wavelengths. While the cells on GaSb substrates in general offer better performance than the cells on GaAs substrates, the cost-savings and scalability offered by GaAs substrates could potentially outweigh the reduction in performance. By further optimizing GaSb buffer growth on GaAs substrates, Sb-based compound semiconductors grown on GaAs substrates with similar performance to devices grown directly on GaSb substrates could be realized.« less

Stimulation of Executive Functions as Part of the Language Intervention Process in Children with Autism Spectrum Disorder.

PubMed

Sun, Ingrid Ya I; Varanda, Cristina Andrade; Fernandes, Fernanda Dreux

2017-01-01

Identifying effective methods for stimulating language and communication of children with autism spectrum disorder (ASD) is fundamental to the effective use of available resources to support these children. This pilot study was designed to explore the potential benefits of a program of stimulation of executive functions (SEF) on the functional aspects of language and communication through the assessment of the functional communicative profile and social-cognitive performance. Twenty children, aged 5-12 years, with a diagnosis of ASD participated in the study. Two stimulation programs were offered over a 10- to 12-week period as part of the regular services offered to these children through a University's speech and language therapy outpatient clinic in São Paulo, Brazil. Children either received SEF intervention in their home implemented by their parent/s, with close monitoring by the speech-language pathologist (SLP) (group 1), or they received SEF by the SLP during regular speech-language therapy individual sessions (group 2). The findings suggested that there were differences between the children's pre- and posttest performance. Significantly different performances were observed in the areas of occupation of communication space, proportion of communicative interactivity, and social-cognitive performance. The inclusion of activities to stimulate executive function abilities in language intervention for children with ASD warrants further investigation. © 2017 S. Karger AG, Basel.

Design and analysis of a direct-drive wind power generator with ultra-high torque density

NASA Astrophysics Data System (ADS)

Jian, Linni; Shi, Yujun; Wei, Jin; Zheng, Yanchong

2015-05-01

In order to get rid of the nuisances caused by mechanical gearboxes, generators with low rated speed, which can be directly connected to wind turbines, are attracting increasing attention. The purpose of this paper is to propose a new direct-drive wind power generator (DWPG), which can offer ultra-high torque density. First, magnetic gear (MG) is integrated to achieve non-contact torque transmission and speed variation. Second, armature windings are engaged to achieve electromechanical energy conversion. Interior permanent magnet (PM) design on the inner rotor is adopted to boost the torque transmission capability of the integrated MG. Nevertheless, due to lack of back iron on the stator, the proposed generator does not exhibit prominent salient feature, which usually exists in traditional interior PM (IPM) machines. This makes it with good controllability and high power factor as the surface-mounted permanent magnet machines. The performance is analyzed using finite element method. Investigation on the magnetic field harmonics demonstrates that the permanent-magnetic torque offered by the MG can work together with the electromagnetic torque offered by the armature windings to balance the driving torque captured by the wind turbine. This allows the proposed generator having the potential to offer even higher torque density than its integrated MG.

Design and Implementation of Scientific Software Components to Enable Multiscale Modeling: The Effective Fragment Potential (QM/EFP) Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaenko, Alexander; Windus, Theresa L.; Sosonkina, Masha

2012-10-19

The design and development of scientific software components to provide an interface to the effective fragment potential (EFP) methods are reported. Multiscale modeling of physical and chemical phenomena demands the merging of software packages developed by research groups in significantly different fields. Componentization offers an efficient way to realize new high performance scientific methods by combining the best models available in different software packages without a need for package readaptation after the initial componentization is complete. The EFP method is an efficient electronic structure theory based model potential that is suitable for predictive modeling of intermolecular interactions in large molecularmore » systems, such as liquids, proteins, atmospheric aerosols, and nanoparticles, with an accuracy that is comparable to that of correlated ab initio methods. The developed components make the EFP functionality accessible for any scientific component-aware software package. The performance of the component is demonstrated on a protein interaction model, and its accuracy is compared with results obtained with coupled cluster methods.« less

X-ray imaging detectors for synchrotron and XFEL sources

PubMed Central

Hatsui, Takaki; Graafsma, Heinz

2015-01-01

Current trends for X-ray imaging detectors based on hybrid and monolithic detector technologies are reviewed. Hybrid detectors with photon-counting pixels have proven to be very powerful tools at synchrotrons. Recent developments continue to improve their performance, especially for higher spatial resolution at higher count rates with higher frame rates. Recent developments for X-ray free-electron laser (XFEL) experiments provide high-frame-rate integrating detectors with both high sensitivity and high peak signal. Similar performance improvements are sought in monolithic detectors. The monolithic approach also offers a lower noise floor, which is required for the detection of soft X-ray photons. The link between technology development and detector performance is described briefly in the context of potential future capabilities for X-ray imaging detectors. PMID:25995846

Advanced Chemical Propulsion Study

NASA Technical Reports Server (NTRS)

Woodcock, Gordon; Byers, Dave; Alexander, Leslie A.; Krebsbach, Al

2004-01-01

A study was performed of advanced chemical propulsion technology application to space science (Code S) missions. The purpose was to begin the process of selecting chemical propulsion technology advancement activities that would provide greatest benefits to Code S missions. Several missions were selected from Code S planning data, and a range of advanced chemical propulsion options was analyzed to assess capabilities and benefits re these missions. Selected beneficial applications were found for higher-performing bipropellants, gelled propellants, and cryogenic propellants. Technology advancement recommendations included cryocoolers and small turbopump engines for cryogenic propellants; space storable propellants such as LOX-hydrazine; and advanced monopropellants. It was noted that fluorine-bearing oxidizers offer performance gains over more benign oxidizers. Potential benefits were observed for gelled propellants that could be allowed to freeze, then thawed for use.

Carbon-Nanotube-Based Electrochemical Double-Layer Capacitor Technologies for Spaceflight Applications

NASA Technical Reports Server (NTRS)

Arepalli, S.; Fireman, H.; Huffman, C.; Maloney, P.; Nikolaev, P.; Yowell, L.; Kim, K.; Kohl, P. A.; Higgins, C. D.; Turano, S. P.

2005-01-01

Electrochemical double-layer capacitors, or supercapacitors, have tremendous potential as high-power energy sources for use in low-weight hybrid systems for space exploration. Electrodes based on single-wall carbon nanotubes (SWCNTs) offer exceptional power and energy performance due to the high surface area, high conductivity, and the ability to functionalize the SWCNTs to optimize capacitor properties. This paper will report on the preparation of electrochemical capacitors incorporating SWCNT electrodes and their performance compared with existing commercial technology. Preliminary results indicate that substantial increases in power and energy density are possible. The effects of nanotube growth and processing methods on electrochemical capacitor performance is also presented. The compatibility of different SWCNTs and electrolytes was studied by varying the type of electrolyte ions that accumulate on the high-surface-area electrodes.

Hybrid boosters for future launch vehicles

NASA Astrophysics Data System (ADS)

Dargies, E.; Lo, R. E.

There is a striking similarity in the design of the US Space Transportation System, the European ARI-ANE 5P and the Japanese II-II: they all use a high energy cryogenic core stage along with two large solid propellant rocket boosters (SRB's) in order to provide for a high lift-off thrust level. Prior to last years disasters with Challenger and Titan it was widely held that SRB's were cheap, uncomplicated and safe. Even before the revelation by these accidents of severe safety hazards, shuttle operations demonstrated that the SRB's were by no means as cheap as reusable systems ought to be. In addition, they became known as sources of considerable environmental pollution. In contrast, hybrid rocket propulsion systems offer the following potential advantages: • much higher savety level (TNT equivalent almost zero, shut-down capability in case of ignition failure of one unit, inert against unbonding) • choice of non-toxic propellant combinations • equal or higher specific performance For these reasons, system analysis were carried out to examine hybrids as potential alternative to SRB's. Various analytical tools (mass- and performance models, trajectory simulation etc.) were developed for parametrical studies of hybrid propulsion systems. Special attention was devoted to the well-known primary concern of hybrids: geometrical design of the solid fuel grain and regression rate of the ablating surface. Experimental data were used as input wherever possible. In 1985 first studies were carried out to find possible fields of application for hybrid rocket engines. A mass model and a performance model for hybrid rocket motors were developed, taking into account the peculiarities of hybrid combustion as there are i.e. low regression rate and shifting mixture ratio during operation. After some analytical work was done, hybrids proved to be a promising alternative to SRB's. Compared with solids, hybrids offer many advantages.

Electrodeposited Structurally Stable V2O5 Inverse Opal Networks as High Performance Thin Film Lithium Batteries.

PubMed

Armstrong, Eileen; McNulty, David; Geaney, Hugh; O'Dwyer, Colm

2015-12-09

High performance thin film lithium batteries using structurally stable electrodeposited V2O5 inverse opal (IO) networks as cathodes provide high capacity and outstanding cycling capability and also were demonstrated on transparent conducting oxide current collectors. The superior electrochemical performance of the inverse opal structures was evaluated through galvanostatic and potentiodynamic cycling, and the IO thin film battery offers increased capacity retention compared to micron-scale bulk particles from improved mechanical stability and electrical contact to stainless steel or transparent conducting current collectors from bottom-up electrodeposition growth. Li(+) is inserted into planar and IO structures at different potentials, and correlated to a preferential exposure of insertion sites of the IO network to the electrolyte. Additionally, potentiodynamic testing quantified the portion of the capacity stored as surface bound capacitive charge. Raman scattering and XRD characterization showed how the IO allows swelling into the pore volume rather than away from the current collector. V2O5 IO coin cells offer high initial capacities, but capacity fading can occur with limited electrolyte. Finally, we demonstrate that a V2O5 IO thin film battery prepared on a transparent conducting current collector with excess electrolyte exhibits high capacities (∼200 mAh g(-1)) and outstanding capacity retention and rate capability.

Femtosecond laser polishing of optical materials

NASA Astrophysics Data System (ADS)

Taylor, Lauren L.; Qiao, Jun; Qiao, Jie

2015-10-01

Technologies including magnetorheological finishing and CNC polishing are commonly used to finish optical elements, but these methods are often expensive, generate waste through the use of fluids or abrasives, and may not be suited for specific freeform substrates due to the size and shape of finishing tools. Pulsed laser polishing has been demonstrated as a technique capable of achieving nanoscale roughness while offering waste-free fabrication, material-specific processing through direct tuning of laser radiation, and access to freeform shapes using refined beam delivery and focusing techniques. Nanosecond and microsecond pulse duration radiation has been used to perform successful melting-based polishing of a variety of different materials, but this approach leads to extensive heat accumulation resulting in subsurface damage. We have experimentally investigated the ability of femtosecond laser radiation to ablate silicon carbide and silicon. By substituting ultrafast laser radiation, polishing can be performed by direct evaporation of unwanted surface asperities with minimal heating and melting, potentially offering damage-free finishing of materials. Under unoptimized laser processing conditions, thermal effects can occur leading to material oxidation. To investigate these thermal effects, simulation of the heat accumulation mechanism in ultrafast laser ablation was performed. Simulations have been extended to investigate the optimum scanning speed and pulse energy required for processing various substrates. Modeling methodologies and simulation results will be presented.

Assessment of the performance of a compact concentric spectrometer system for Atmospheric Differential Optical Absorption Spectroscopy

NASA Astrophysics Data System (ADS)

Whyte, C.; Leigh, R. J.; Lobb, D.; Williams, T.; Remedios, J. J.; Cutter, M.; Monks, P. S.

2009-08-01

A breadboard demonstrator of a novel UV/VIS grating spectrometer for atmospheric research has been developed based upon a concentric arrangement of a spherical meniscus lens, concave spherical mirror and curved diffraction grating suitable for a range of remote sensing applications from the ground or space. The spectrometer is compact and provides high optical efficiency and performance benefits over traditional instruments. The concentric design is capable of handling high relative apertures, owing to spherical aberration and coma being near zero at all surfaces. The design also provides correction for transverse chromatic aberration and distortion, in addition to correcting for the distortion called "smile", the curvature of the slit image formed at each wavelength. These properties render this design capable of superior spectral and spatial performance with size and weight budgets significantly lower than standard configurations. This form of spectrometer design offers the potential for an exceptionally compact instrument for differential optical absorption spectroscopy (DOAS) applications particularly from space (LEO, GEO orbits) and from HAPs or ground-based platforms. The breadboard demonstrator has been shown to offer high throughput and a stable Gaussian line shape with a spectral range from 300 to 450 nm at better than 0.5 nm resolution, suitable for a number of typical DOAS applications.

The next generation of solar panel substrates?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gledhill, K.M.; Boswell, R.L.; Paul, J.G.

For over 25 years, satellite power system designers have used rigid honeycomb panels as solar array substrates. Those years have seen very little improvement in the performance of these rigid systems. A new technology under development at the Phillips Laboratory, however, may undo this stagnancy. Composite isogrid panel structures offer a number of potential advantages over honeycomb sandwich structures for solar array applications, including stiffness, weight, and cost improvements. Phillips Laboratory will be performing a series of evaluative tests on the isogrid structure to determine its suitability as a substitute for honeycomb sandwiches in solar panel applications. Testing will includemore » three-point bending, thermal vacuum, and thermal cycling.« less

Super NiCd Open-Circuit Storage and Low Earth Orbit (LEO) Life Test Evaluation

NASA Technical Reports Server (NTRS)

Baer, Jean Marie; Hwang, Warren C.; Ang, Valerie J.; Hayden, Jeff; Rao, Gopalakrishna; Day, John H. (Technical Monitor)

2002-01-01

This presentation discusses Air Force tests performed on super NiCd cells to measure their performance under conditions simulating Low Earth Orbit (LEO) conditions. Super NiCd cells offer potential advantages over existing NiCd cell designs including advanced cell design with improved separator material and electrode making processes, but handling and storage requires active charging. These tests conclude that the super NiCd cells support generic Air Force qualifications for conventional LEO missions (up to five years duration) and that handling and storage may not actually require active charging as previously assumed. Topics covered include: Test Plan, Initial Characterization Tests, Open-Circuit Storage Tests, and post storage capacities.

Development of new materials for turbopump bearings

NASA Technical Reports Server (NTRS)

Maurer, R. E.; Pallini, R. A.

1985-01-01

The life requirement for the angular contact ball bearings in the Space Shuttle Main Engine (SSME) high pressure oxygen turbopump (HPOTP) is 7.5 hours. In actual operation, significantly shorter service life was experienced. The objective is to identify bearing materials and/or materials processing techniques offering signficant potential for extending HPOTP bearing performance life. Interactive thermomechanical analysis of the HPOTP bearing-shaft system was performed with the SHABERTH computer program. Bearing fatigue life, ball-race contact stress, heat generation rate, bulk ring temperatures and circumferential stress in the inner rings were quantified as functions of radial load, thrust load and ball-race contact friction. Criteria established from the output of this analysis are being used for material candidate selection.

Principles and performance of tapered fiber lasers: from uniform to flared geometry.

PubMed

Kerttula, Juho; Filippov, Valery; Chamorovskii, Yuri; Ustimchik, Vasily; Golant, Konstantin; Okhotnikov, Oleg G

2012-10-10

We have studied the recently demonstrated concept of fiber lasers based on active tapered double-clad fiber (T-DCF) in copropagating and counterpropagating configurations, both theoretically and experimentally, and compared the performance to fiber lasers based on conventional cylindrical fibers in end-pumped configurations. Specific properties of T-DCFs were considered theoretically using a rate-equation model developed for tapered fibers, and a detailed comparative study was carried out experimentally. Furthermore, we have studied mode coupling effects in long adiabatic tapers due to coiling and local bending. The results allow us to conclude that, with proper fiber design, the T-DCF technology offers a high-potential alternative for bright, cost-effective fiber devices.

Hyperspectral imaging utility for transportation systems

NASA Astrophysics Data System (ADS)

Bridgelall, Raj; Rafert, J. Bruce; Tolliver, Denver

2015-03-01

The global transportation system is massive, open, and dynamic. Existing performance and condition assessments of the complex interacting networks of roadways, bridges, railroads, pipelines, waterways, airways, and intermodal ports are expensive. Hyperspectral imaging is an emerging remote sensing technique for the non-destructive evaluation of multimodal transportation infrastructure. Unlike panchromatic, color, and infrared imaging, each layer of a hyperspectral image pixel records reflectance intensity from one of dozens or hundreds of relatively narrow wavelength bands that span a broad range of the electromagnetic spectrum. Hence, every pixel of a hyperspectral scene provides a unique spectral signature that offers new opportunities for informed decision-making in transportation systems development, operations, and maintenance. Spaceborne systems capture images of vast areas in a short period but provide lower spatial resolution than airborne systems. Practitioners use manned aircraft to achieve higher spatial and spectral resolution, but at the price of custom missions and narrow focus. The rapid size and cost reduction of unmanned aircraft systems promise a third alternative that offers hybrid benefits at affordable prices by conducting multiple parallel missions. This research formulates a theoretical framework for a pushbroom type of hyperspectral imaging system on each type of data acquisition platform. The study then applies the framework to assess the relative potential utility of hyperspectral imaging for previously proposed remote sensing applications in transportation. The authors also introduce and suggest new potential applications of hyperspectral imaging in transportation asset management, network performance evaluation, and risk assessments to enable effective and objective decision- and policy-making.

Persuasive Performance Feedback: The Effect of Framing on Self-Efficacy

PubMed Central

Choe, Eun Kyoung; Lee, Bongshin; Munson, Sean; Pratt, Wanda; Kientz, Julie A.

2013-01-01

Self-monitoring technologies have proliferated in recent years as they offer excellent potential for promoting healthy behaviors. Although these technologies have varied ways of providing real-time feedback on a user’s current progress, we have a dearth of knowledge of the framing effects on the performance feedback these tools provide. With an aim to create influential, persuasive performance feedback that will nudge people toward healthy behaviors, we conducted an online experiment to investigate the effect of framing on an individual’s self-efficacy. We identified 3 different types of framing that can be applicable in presenting performance feedback: (1) the valence of performance (remaining vs. achieved framing), (2) presentation type (text-only vs. text with visual), and (3) data unit (raw vs. percentage). Results show that the achieved framing could lead to an increased perception of individual’s performance capabilities. This work provides empirical guidance for creating persuasive performance feedback, thereby helping people designing self-monitoring technologies to promote healthy behaviors. PMID:24551378

Persuasive performance feedback: the effect of framing on self-efficacy.

PubMed

Choe, Eun Kyoung; Lee, Bongshin; Munson, Sean; Pratt, Wanda; Kientz, Julie A

2013-01-01

Self-monitoring technologies have proliferated in recent years as they offer excellent potential for promoting healthy behaviors. Although these technologies have varied ways of providing real-time feedback on a user's current progress, we have a dearth of knowledge of the framing effects on the performance feedback these tools provide. With an aim to create influential, persuasive performance feedback that will nudge people toward healthy behaviors, we conducted an online experiment to investigate the effect of framing on an individual's self-efficacy. We identified 3 different types of framing that can be applicable in presenting performance feedback: (1) the valence of performance (remaining vs. achieved framing), (2) presentation type (text-only vs. text with visual), and (3) data unit (raw vs. percentage). Results show that the achieved framing could lead to an increased perception of individual's performance capabilities. This work provides empirical guidance for creating persuasive performance feedback, thereby helping people designing self-monitoring technologies to promote healthy behaviors.

Energy conversion performance of black liquor gasification to hydrogen production using direct causticization with CO(2) capture.

PubMed

Naqvi, M; Yan, J; Dahlquist, E

2012-04-01

This paper estimates potential hydrogen production via dry black liquor gasification system with direct causticization integrated with a reference pulp mill. The advantage of using direct causticization is elimination of energy intensive lime kiln. Pressure swing adsorption is integrated in the carbon capture process for hydrogen upgrading. The energy conversion performance of the integrated system is compared with other bio-fuel alternatives and evaluated based on system performance indicators. The results indicated a significant hydrogen production potential (about 141MW) with an energy ratio of about 0.74 from the reference black liquor capacity (about 243.5MW) and extra biomass import (about 50MW) to compensate total energy deficit. About 867,000tonnes of CO(2) abatement per year is estimated i.e. combining CO(2) capture and CO(2) offset from hydrogen replacing motor gasoline. The hydrogen production offers a substantial motor fuel replacement especially in regions with large pulp and paper industry e.g. about 63% of domestic gasoline replacement in Sweden. Copyright © 2012 Elsevier Ltd. All rights reserved.

European Regional Climate Zone Modeling of a Commercial Absorption Heat Pump Hot Water Heater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Vishaldeep; Shen, Bo; Keinath, Chris

2017-01-01

High efficiency gas-burning hot water heating takes advantage of a condensing heat exchanger to deliver improved combustion efficiency over a standard non-condensing configuration. The water heating is always lower than the gas heating value. In contrast, Gas Absorption Heat Pump (GAHP) hot water heating combines the efficiency of gas burning with the performance increase from a heat pump to offer significant gas energy savings. An ammonia-water system also has the advantage of zero Ozone Depletion Potential and low Global Warming Potential. In comparison with air source electric heat pumps, the absorption system can maintain higher coefficients of performance in coldermore » climates. In this work, a GAHP commercial water heating system was compared to a condensing gas storage system for a range of locations and climate zones across Europe. The thermodynamic performance map of a single effect ammonia-water absorption system was used in a building energy modeling software that could also incorporate the changing ambient air temperature and water mains temperature for a specific location, as well as a full-service restaurant water draw pattern.« less

High-Fidelity Aerostructural Design Optimization of Transport Aircraft with Continuous Morphing Trailing Edge Technology

NASA Astrophysics Data System (ADS)

Burdette, David A., Jr.

Adaptive morphing trailing edge technology offers the potential to decrease the fuel burn of transonic commercial transport aircraft by allowing wings to dynamically adjust to changing flight conditions. Current configurations allow flap and aileron droop; however, this approach provides limited degrees of freedom and increased drag produced by gaps in the wing's surface. Leading members in the aeronautics community including NASA, AFRL, Boeing, and a number of academic institutions have extensively researched morphing technology for its potential to improve aircraft efficiency. With modern computational tools it is possible to accurately and efficiently model aircraft configurations in order to quantify the efficiency improvements offered by mor- phing technology. Coupled high-fidelity aerodynamic and structural solvers provide the capability to model and thoroughly understand the nuanced trade-offs involved in aircraft design. This capability is important for a detailed study of the capabilities of morphing trailing edge technology. Gradient-based multidisciplinary design opti- mization provides the ability to efficiently traverse design spaces and optimize the trade-offs associated with the design. This thesis presents a number of optimization studies comparing optimized config- urations with and without morphing trailing edge devices. The baseline configuration used throughout this work is the NASA Common Research Model. The first opti- mization comparison considers the optimal fuel burn predicted by the Breguet range equation at a single cruise point. This initial singlepoint optimization comparison demonstrated a limited fuel burn savings of less than 1%. Given the effectiveness of the passive aeroelastic tailoring in the optimized non-morphing wing, the singlepoint optimization offered limited potential for morphing technology to provide any bene- fit. To provide a more appropriate comparison, a number of multipoint optimizations were performed. With a 3-point stencil, the morphing wing burned 2.53% less fuel than its optimized non-morphing counterpart. Expanding further to a 7-point stencil, the morphing wing used 5.04% less fuel. Additional studies demonstrate that the size of the morphing device can be reduced without sizable performance reductions, and that as aircraft wings' aspect ratios increase, the effectiveness of morphing trailing edge devices increases. The final set of studies in this thesis consider mission analy- sis, including climb, multi-altitude cruise, and descent. These mission analyses were performed with a number of surrogate models, trained with O(100) optimizations. These optimizations demonstrated fuel burn reductions as large as 5% at off-design conditions. The fuel burn predicted by the mission analysis was up to 2.7% lower for the morphing wing compared to the conventional configuration.

Early warning system for potential churners among mortgage customers

NASA Astrophysics Data System (ADS)

Irpan, Hamidah Muhd; Aidid, Sharifah Sakinah Syed Hassan; Mohmad, Sarahiza; Ibrahim, Noorazilah

2014-07-01

Retaining existing customer is a major task for many companies because cost to acquire new customers is higher than retaining existing customers. For mortgage business in Bank X, customer relationship management plays a big role to understand their customers' profile and churners so that suitable action can be done to retain their potential churners. Objectives of this study are (1) understanding their customers' profile and churners, (2) modeling potential churners using neural network model and (3) to deploy the model to identify potential churners. Data was divided into two parts: sampling (67,470 cases) and scoring (4,488 cases). Analysis was done using SAS Enterprise Miner. Dependent variable is churner/non churner while independent variables are balance and amount of loan, interest rate offered installment amount, loan performance, months in arrear, vintage, tenure, age, race and gender. Potential churners were identified as Malays, followed by Indian, other races and Chinese. Nonperforming loan and male customers tend to churn compared to performing loan and female customers. Younger customers with small loan amount, balance and monthly instalment, higher interest rate, have many months in arrears, longer vintage and tenure have higher tendency to churn from Bank X. Hence, Bank X should focus on the potential churners for their campaign to minimize the expenses of retaining existing customers by doing an effective campaign with high successful rate.

Clinical and Radiographic Evaluation of Allium sativum Oil as a New Medicament for Vital Pulp Treatment of Primary Teeth.

PubMed

Mohammad, Shukry Gamal; Raheel, Syed Ahmed; Baroudi, Kusai

2014-01-01

The objective of this study was to compare between the clinical and radiographic effects of Allium sativum oil and those of formocresol in vital pulpotomy in primary teeth. A total of 20 children age ranged from 4 to 8 years were included in the study. In every one of those children, the primary molars indicated for pulpotomy. Pulpotomy procedure was performed, and the radicular pulp tissue of one molar capped with A. sativum oil in a cotton pellet, whereas the other molar capped with formocresol, the teeth evaluated clinically and radiographically before and after 6 months, using standard clinical and radiographical criteria. Statistically, these results revealed no significant difference between the radiographic findings of vital pulpotomy in primary molars with the two medicaments was found. A. sativum oil offers a good healing potential, leaving the remaining pulp tissue healthy and functioning. Vital pulpotomy with allium sativa oil was given raise 90% success rate while that with formocresol was 85%. A. sativum oil is a biocompatible material that is compatible with vital human pulp tissue. It offers a good healing potential, leaving the remaining pulp tissue healthy and functioning.

Clinical and Radiographic Evaluation of Allium sativum Oil as a New Medicament for Vital Pulp Treatment of Primary Teeth

PubMed Central

Mohammad, Shukry Gamal; Raheel, Syed Ahmed; Baroudi, Kusai

2014-01-01

Background: The objective of this study was to compare between the clinical and radiographic effects of Allium sativum oil and those of formocresol in vital pulpotomy in primary teeth. Materials and Methods: A total of 20 children age ranged from 4 to 8 years were included in the study. In every one of those children, the primary molars indicated for pulpotomy. Pulpotomy procedure was performed, and the radicular pulp tissue of one molar capped with A. sativum oil in a cotton pellet, whereas the other molar capped with formocresol, the teeth evaluated clinically and radiographically before and after 6 months, using standard clinical and radiographical criteria. Statistically, these results revealed no significant difference between the radiographic findings of vital pulpotomy in primary molars with the two medicaments was found. Results: A. sativum oil offers a good healing potential, leaving the remaining pulp tissue healthy and functioning. Vital pulpotomy with allium sativa oil was given raise 90% success rate while that with formocresol was 85%. Conclusion: A. sativum oil is a biocompatible material that is compatible with vital human pulp tissue. It offers a good healing potential, leaving the remaining pulp tissue healthy and functioning. PMID:25628480

1300 nm and 890 nm OCT images of oral cancer tissue engineered models and biopsy samples offer complimentary performance (Conference Presentation)

NASA Astrophysics Data System (ADS)

Boadi, Joseph; Byers, Robert A.; Fernandes, Jon; Mittar, Shweta; Hearnden, Vanessa; Lu, Zenghai; MacNeil, Sheila; Thornhill, Martin; Murdoch, Craig; Hunter, Keith D.; McKechnie, Alasdair; Matcher, Stephen J.

2016-02-01

OCT has demonstrated great potential to non-invasively detect oral epithelial cancers, potentially guiding biopsy and surgical resection. On non-ophthalmic tissues the preferred illumination wavelength is 1300 nm. Previous studies on skin have shown that useful image data can also be obtained at shorter wavelengths, with systems at 1060 nm and 820 nm offering reduced depth penetration but higher contrast. Here we apply a similar comparison to tissue engineered models of oral cancer and also to human biopsy samples, generally finding a similar trend. 1300 nm multi-beam OCT (Michelson Diagnostics EX1301) visualises stromal structures and surface keratin more clearly, providing useful image contrast down to around 1 mm. This system was compared with an ultra-high resolution home-built system operating at 890 nm (2.5 micron resolution vs 7.5 micron axial resolution for the EX1301). The UHR system reveals epithelial features more clearly, especially in the DOK pre-invasive cell line model and the biopsy samples. The relative effects of center wavelength vs axial resolution in generating the differential, wavelength-dependent contrast are assessed and the OCT biopsy images are compared with contemporary histology.

Exploring the potential uses of value-added metrics in the context of postgraduate medical education.

PubMed

Gregory, Simon; Patterson, Fiona; Baron, Helen; Knight, Alec; Walsh, Kieran; Irish, Bill; Thomas, Sally

2016-10-01

Increasing pressure is being placed on external accountability and cost efficiency in medical education and training internationally. We present an illustrative data analysis of the value-added of postgraduate medical education. We analysed historical selection (entry) and licensure (exit) examination results for trainees sitting the UK Membership of the Royal College of General Practitioners (MRCGP) licensing examination (N = 2291). Selection data comprised: a clinical problem solving test (CPST); a situational judgement test (SJT); and a selection centre (SC). Exit data was an applied knowledge test (AKT) from MRCGP. Ordinary least squares (OLS) regression analyses were used to model differences in attainment in the AKT based on performance at selection (the value-added score). Results were aggregated to the regional level for comparisons. We discovered significant differences in the value-added score between regional training providers. Whilst three training providers confer significant value-added, one training provider was significantly lower than would be predicted based on the attainment of trainees at selection. Value-added analysis in postgraduate medical education potentially offers useful information, although the methodology is complex, controversial, and has significant limitations. Developing models further could offer important insights to support continuous improvement in medical education in future.

Fiber-reinforced ceramic composites for Earth-to-orbit rocket engine turbines

NASA Technical Reports Server (NTRS)

Brockmeyer, Jerry W.; Schnittgrund, Gary D.

1990-01-01

Fiber reinforced ceramic matrix composites (FRCMC) are emerging materials systems that offer potential for use in liquid rocket engines. Advantages of these materials in rocket engine turbomachinery include performance gain due to higher turbine inlet temperature, reduced launch costs, reduced maintenance with associated cost benefits, and reduced weight. This program was initiated to assess the state of FRCMC development and to propose a plan for their implementation into liquid rocket engine turbomachinery. A complete range of FRCMC materials was investigated relative to their development status and feasibility for use in the hot gas path of earth-to-orbit rocket engine turbomachinery. Of the candidate systems, carbon fiber-reinforced silicon carbide (C/SiC) offers the greatest near-term potential. Critical hot gas path components were identified, and the first stage inlet nozzle and turbine rotor of the fuel turbopump for the liquid oxygen/hydrogen Space Transportation Main Engine (STME) were selected for conceptual design and analysis. The critical issues associated with the use of FRCMC were identified. Turbine blades were designed, analyzed and fabricated. The Technology Development Plan, completed as Task 5 of this program, provides a course of action for resolution of these issues.

Water Photo-oxidation Initiated by Surface-Bound Organic Chromophores.

PubMed

Eberhart, Michael S; Wang, Degao; Sampaio, Renato N; Marquard, Seth L; Shan, Bing; Brennaman, M Kyle; Meyer, Gerald J; Dares, Christopher; Meyer, Thomas J

2017-11-15

Organic chromophores can be synthesized by established methods and offer an opportunity to expand overall solar spectrum utilization for dye-sensitized photoelectrosynthesis cells. However, there are complications in the use of organic chromophores arising from the instability of their oxidized forms, the inability of their oxidized forms to activate a water oxidation catalyst, or the absence of a sufficiently reducing excited state for electron injection into appropriate semiconductors. Three new triarylamine donor-acceptor organic dyes have been investigated here for visible-light-driven water oxidation. They offer highly oxidizing potentials (>1 V vs NHE in aqueous solution) that are sufficient to drive a water oxidation catalyst and excited-state potentials (∼-1.2 V vs NHE) sufficient to inject into TiO 2 . The oxidized form of one of the chromophores is sufficiently stable to exhibit reversible electrochemistry in aqueous solution. The chromophores also have favorable photophysics. Visible-light-driven oxygen production by an organic chromophore for up to 1 h of operation has been demonstrated with reasonable faradaic efficiencies for measured O 2 production. The properties of organic chromophores necessary for successfully driving water oxidation in a light-driven system are explored along with strategies for improving device performance.

Inorganic photovoltaic devices fabricated using nanocrystal spray deposition.

PubMed

Foos, Edward E; Yoon, Woojun; Lumb, Matthew P; Tischler, Joseph G; Townsend, Troy K

2013-09-25

Soluble inorganic nanocrystals offer a potential route to the fabrication of all-inorganic devices using solution deposition techniques. Spray processing offers several advantages over the more common spin- and dip-coating procedures, including reduced material loss during fabrication, higher sample throughput, and deposition over a larger area. The primary difference observed, however, is an overall increase in the film roughness. In an attempt to quantify the impact of this morphology change on the devices, we compare the overall performance of spray-deposited versus spin-coated CdTe-based Schottky junction solar cells and model their dark current-voltage characteristics. Spray deposition of the active layer results in a power conversion efficiency of 2.3 ± 0.3% with a fill factor of 45.7 ± 3.4%, Voc of 0.39 ± 0.06 V, and Jsc of 13.3 ± 3.0 mA/cm(2) under one sun illumination.

Ka-band MMIC subarray technology program (Ka-Mist)

NASA Technical Reports Server (NTRS)

Pottenger, Warren

1995-01-01

The broad objective of this program was to demonstrate a proof of concept insertion of Monolithic Microwave Integrated Circuit (MMIC) device technology into an innovative (tile architecture) active phased array antenna application supporting advanced EHF communication systems. Ka-band MMIC arrays have long been considered as having high potential for increasing the capability of space, aircraft, and land mobile communication systems in terms of scan performance, data rate, link margin, and flexibility while offering a significant reduction in size, weight, and power consumption. Insertion of MMIC technology into antenna systems, particularly at millimeter wave frequencies using low power and low noise amplifiers in close proximity to the radiating elements, offers a significant improvement in the array transmit efficiency, receive system noise figure, and overall array reliability. Application of active array technology also leads to the use of advanced beamforming techniques that can improve beam agility, diversity, and adaptivity to complex signal environments.

Bioresorbable silicon electronics for transient spatiotemporal mapping of electrical activity from the cerebral cortex.

PubMed

Yu, Ki Jun; Kuzum, Duygu; Hwang, Suk-Won; Kim, Bong Hoon; Juul, Halvor; Kim, Nam Heon; Won, Sang Min; Chiang, Ken; Trumpis, Michael; Richardson, Andrew G; Cheng, Huanyu; Fang, Hui; Thomson, Marissa; Bink, Hank; Talos, Delia; Seo, Kyung Jin; Lee, Hee Nam; Kang, Seung-Kyun; Kim, Jae-Hwan; Lee, Jung Yup; Huang, Younggang; Jensen, Frances E; Dichter, Marc A; Lucas, Timothy H; Viventi, Jonathan; Litt, Brian; Rogers, John A

2016-07-01

Bioresorbable silicon electronics technology offers unprecedented opportunities to deploy advanced implantable monitoring systems that eliminate risks, cost and discomfort associated with surgical extraction. Applications include postoperative monitoring and transient physiologic recording after percutaneous or minimally invasive placement of vascular, cardiac, orthopaedic, neural or other devices. We present an embodiment of these materials in both passive and actively addressed arrays of bioresorbable silicon electrodes with multiplexing capabilities, which record in vivo electrophysiological signals from the cortical surface and the subgaleal space. The devices detect normal physiologic and epileptiform activity, both in acute and chronic recordings. Comparative studies show sensor performance comparable to standard clinical systems and reduced tissue reactivity relative to conventional clinical electrocorticography (ECoG) electrodes. This technology offers general applicability in neural interfaces, with additional potential utility in treatment of disorders where transient monitoring and modulation of physiologic function, implant integrity and tissue recovery or regeneration are required.

Silicon Photo-Multiplier Readouts for Scintillators in High-Energy Astronomy

NASA Technical Reports Server (NTRS)

Bloser, Peter F.; Legere, Jason S.; Bancroft, Christopher M.; McConnell, Mark L.; Ryan, James M.

2008-01-01

New scintillator materials have recently been shown to hold great potential for low-cost, reliable gamma-ray detectors in high-energy astronomy. New devices for the detection of scintillation light promise to make scintillator-based instruments even more attractive by reducing mass and power requirements,in particular, silicon photo-multipliers (SiPMs) are starting to become commercially available that offer gains and quantum efficiencies similar to those of photo-multiplier tubes (PMTs), but with greatly reduced mass, high ruggedness, low voltage requirements, and no sensitivity to magnetic fields. We have conducted laboratory tests of a sample of commercially available SiPMs coupled to LaBr3;Ce, a scintillator of relevance to to future high-energy astrophysics missions. We present results for gamma-ray spectroscopy. compare the SiPM performance to that of a PMT, and discuss the extent to which SiPMs offer significant advantages for scintillator-based space missions.

Illumination, data transmission, and energy harvesting: the threefold advantage of VLC.

PubMed

Sandalidis, Harilaos G; Vavoulas, Alexander; Tsiftsis, Theodoros A; Vaiopoulos, Nicholas

2017-04-20

Visible light communication (VLC) is a promising technology that meets illumination and information transmission requirements in an indoor environment. Because light waves convey energy, a VLC link may exploit that fact for energy harvesting purposes. In this context, a single light emitting diode lamp located at a close distance over a tablet or laptop PC can potentially offer simultaneous lighting, Internet access, and battery recharging without cables. The present study introduces this threefold role of VLC systems by properly adapting some energy harvesting receiver architectures recently launched for usage in RF communications. The rate-energy trade-off for these architectures is revealed in order to maximize the efficiency of simultaneous energy and information reception, by elaborating on indicative numerical results. Furthermore, the performance in terms of the bit-error rate for pulse amplitude modulated signals is investigated. The results obtained offer some useful insights into the effective optical receiver implementation from the aspect of information theory.

Formation of the priority directions of innovative strategic energy management

NASA Astrophysics Data System (ADS)

Mottaeva, Asiiat; Minnullina, Anna

2017-10-01

Article is devoted to the matter of the ensuring long-term potential of dynamic growth of the Russian economy, its sustainable development in which the special role is assigned to the energy industry. Inclusion of the stage of management of the human capital, which becomes one of priority levers in the field of management of the industrial enterprises, into the in structure of strategy of planning subsequently represents one of innovative steps at the heart of power management. In work the algorithm of the development of the key performance indicators of the human capital on the basis of stage-by-stage problem definition of energy saving, search of the centers of responsibility in energy consumption and quality control of the involved productions is offered in the article. The application of the offered innovative algorithm might promote the formation of high culture of energy saving and the decrease in the level of resistance to organizational changes.

Protonic Conduction of BaCe0.85YO. 1503 Doped with SrTiO3

NASA Technical Reports Server (NTRS)

Dynys, Frederick W.; Sayir, Ali

2005-01-01

Reformers based on ceramic membrane technology potentially offer hydrogen production that is comparable to the cost of fossil fuels. Protonic conducting ceramic with the chemical formula AB03 offers the promise of highly selective hydrogen separation at intermediate temperature (400-800 C). Among different perovskite-type oxides, BaCe03 and SrCe03 based compositions show high protonic conductivities but strong resistance to densification. X-ray diffraction studies on sintered specimens of BaCe0.85Y0.1503-6 show multi-phase formation which was found to show dependence upon powder synthesis method. Doping with SrTiO3 suppresses multi-phase formation and enhances grain growth. Conductivity measurements in temperature range of 200 to 1000 C were performed by ac impedance spectroscopy under dry and wet conditions. Sintering behavior, phase formation and conductivity results will be reported.

Nanophotonic applications for silicon-on-insulator (SOI)

NASA Astrophysics Data System (ADS)

de la Houssaye, Paul R.; Russell, Stephen D.; Shimabukuro, Randy L.

2004-07-01

Silicon-on-insulator is a proven technology for very large scale integration of microelectronic devices. The technology also offers the potential for development of nanophotonic devices and the ability to interface such devices to the macroscopic world. This paper will report on fabrication techniques used to form nano-structured silicon wires on an insulating structure that is amenable to interfacing nanostructured sensors with high-performance microelectronic circuitry for practical implementation. Nanostructures formed on silicon-on-sapphire can also exploit the transparent substrate for novel device geometries. This research harnesses the unique properties of a high-quality single crystal film of silicon on sapphire and uses the film thickness as one of the confinement dimensions. Lateral arrays of silicon nanowires were fabricated in the thin (5 to 20 nm) silicon layer and studied. This technique offers simplified contact to individual wires and provides wire surfaces that are more readily accessible for controlled alteration and device designs.

Student-written single-best answer questions predict performance in finals.

PubMed

Walsh, Jason; Harris, Benjamin; Tayyaba, Saadia; Harris, David; Smith, Phil

2016-10-01

Single-best answer (SBA) questions are widely used for assessment in medical schools; however, often clinical staff have neither the time nor the incentive to develop high-quality material for revision purposes. A student-led approach to producing formative SBA questions offers a potential solution. Cardiff University School of Medicine students created a bank of SBA questions through a previously described staged approach, involving student question-writing, peer-review and targeted senior clinician input. We arranged questions into discrete tests and posted these online. Student volunteer performance on these tests from the 2012/13 cohort of final-year medical students was recorded and compared with the performance of these students in medical school finals (knowledge and objective structured clinical examinations, OSCEs). In addition, we compared the performance of students that participated in question-writing groups with the performance of the rest of the cohort on the summative SBA assessment. Often clinical staff have neither the time nor the incentive to develop high-quality material for revision purposes Performance in the end-of-year summative clinical knowledge SBA paper correlated strongly with performance in the formative student-written SBA test (r = ~0.60, p <0.01). There was no significant correlation between summative OSCE scores and formative student-written SBA test scores. Students who wrote and reviewed questions scored higher than average in the end-of-year summative clinical knowledge SBA paper. Student-written SBAs predict performance in end-of-year SBA examinations, and therefore can provide a potentially valuable revision resource. There is potential for student-written questions to be incorporated into summative examinations. © 2015 John Wiley & Sons Ltd.

Advanced stratified charge rotary aircraft engine design study

NASA Technical Reports Server (NTRS)

Badgley, P.; Berkowitz, M.; Jones, C.; Myers, D.; Norwood, E.; Pratt, W. B.; Ellis, D. R.; Huggins, G.; Mueller, A.; Hembrey, J. H.

1982-01-01

A technology base of new developments which offered potential benefits to a general aviation engine was compiled and ranked. Using design approaches selected from the ranked list, conceptual design studies were performed of an advanced and a highly advanced engine sized to provide 186/250 shaft Kw/HP under cruise conditions at 7620/25,000 m/ft altitude. These are turbocharged, direct-injected stratified charge engines intended for commercial introduction in the early 1990's. The engine descriptive data includes tables, curves, and drawings depicting configuration, performance, weights and sizes, heat rejection, ignition and fuel injection system descriptions, maintenance requirements, and scaling data for varying power. An engine-airframe integration study of the resulting engines in advanced airframes was performed on a comparative basis with current production type engines. The results show airplane performance, costs, noise & installation factors. The rotary-engined airplanes display substantial improvements over the baseline, including 30 to 35% lower fuel usage.

A new thermally driven refrigeration system with environmental benefits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garris, C.A. Jr.; Hong, W.J.; Mavriplis, C.

1998-07-01

The pressure-exchange ejector offers the possibility of attaining a breakthrough in the level of performance of ejectors by means of utilizing non-dissipative non-steady flow mechanisms. Yet, the device retains much of the mechanical simplicity of conventional steady-flow ejectors. If such a substantial improvement in performance is demonstrated, its application to ejector refrigeration will be very important. Such a development would provide significant benefits for the environment in terms of both CFC usage reduction and greenhouse gas reduction. The current paper will discuss in detail the concept of pressure-exchange ejector refrigeration, compare it with existing technologies, and discuss the potential impactmore » that might be derived if certain levels of ejector performance can be achieved. Since the limiting issue on the system performance is in the fluid dynamics of non-steady flow induction, research issues and recent progress will be discussed.« less

Dense and Sparse Matrix Operations on the Cell Processor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Samuel W.; Shalf, John; Oliker, Leonid

2005-05-01

The slowing pace of commodity microprocessor performance improvements combined with ever-increasing chip power demands has become of utmost concern to computational scientists. Therefore, the high performance computing community is examining alternative architectures that address the limitations of modern superscalar designs. In this work, we examine STI's forthcoming Cell processor: a novel, low-power architecture that combines a PowerPC core with eight independent SIMD processing units coupled with a software-controlled memory to offer high FLOP/s/Watt. Since neither Cell hardware nor cycle-accurate simulators are currently publicly available, we develop an analytic framework to predict Cell performance on dense and sparse matrix operations, usingmore » a variety of algorithmic approaches. Results demonstrate Cell's potential to deliver more than an order of magnitude better GFLOP/s per watt performance, when compared with the Intel Itanium2 and Cray X1 processors.« less

Heart failure services in the United Kingdom: rethinking the machine bureaucracy.

PubMed

Hawkins, Nathaniel M; Wright, David J; Capewell, Simon

2013-01-20

Poor outcomes and poor uptake of evidence based therapies persist for patients with heart failure in the United Kingdom. We offer a strategic analysis of services, defining the context, organization and objectives of the service, before focusing on implementation and performance. Critical flaws in past service development and performance are apparent, a consequence of failed performance management, policy and political initiative. The barriers to change and potential solutions are common to many health care systems. Integration, information, financing, incentives, innovation and values: all must be challenged and improved if heart failure services are to succeed. Modern healthcare requires open adaptive systems, continually learning and improving. The system also needs controls. Performance indicators should be simple, clinically relevant, and outcome focused. Heart failure presents one of the greatest opportunities to improve symptoms and survival with existing technology. To do so, heart failure services require radical reorganization. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Carbon and Carbon Hybrid Materials as Anodes for Sodium-Ion Batteries.

PubMed

Zhong, Xiongwu; Wu, Ying; Zeng, Sifan; Yu, Yan

2018-02-12

Sodium-ion batteries (SIBs) have attracted much attention for application in large-scale grid energy storage owing to the abundance and low cost of sodium sources. However, low energy density and poor cycling life hinder practical application of SIBs. Recently, substantial efforts have been made to develop electrode materials to push forward large-scale practical applications. Carbon materials can be directly used as anode materials, and they show excellent sodium storage performance. Additionally, designing and constructing carbon hybrid materials is an effective strategy to obtain high-performance anodes for SIBs. In this review, we summarize recent research progress on carbon and carbon hybrid materials as anodes for SIBs. Nanostructural design to enhance the sodium storage performance of anode materials is discussed, and we offer some insight into the potential directions of and future high-performance anode materials for SIBs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reference-Free Removal of EEG-fMRI Ballistocardiogram Artifacts with Harmonic Regression

PubMed Central

Krishnaswamy, Pavitra; Bonmassar, Giorgio; Poulsen, Catherine; Pierce, Eric T; Purdon, Patrick L.; Brown, Emery N.

2016-01-01

Combining electroencephalogram (EEG) recording and functional magnetic resonance imaging (fMRI) offers the potential for imaging brain activity with high spatial and temporal resolution. This potential remains limited by the significant ballistocardiogram (BCG) artifacts induced in the EEG by cardiac pulsation-related head movement within the magnetic field. We model the BCG artifact using a harmonic basis, pose the artifact removal problem as a local harmonic regression analysis, and develop an efficient maximum likelihood algorithm to estimate and remove BCG artifacts. Our analysis paradigm accounts for time-frequency overlap between the BCG artifacts and neurophysiologic EEG signals, and tracks the spatiotemporal variations in both the artifact and the signal. We evaluate performance on: simulated oscillatory and evoked responses constructed with realistic artifacts; actual anesthesia-induced oscillatory recordings; and actual visual evoked potential recordings. In each case, the local harmonic regression analysis effectively removes the BCG artifacts, and recovers the neurophysiologic EEG signals. We further show that our algorithm outperforms commonly used reference-based and component analysis techniques, particularly in low SNR conditions, the presence of significant time-frequency overlap between the artifact and the signal, and/or large spatiotemporal variations in the BCG. Because our algorithm does not require reference signals and has low computational complexity, it offers a practical tool for removing BCG artifacts from EEG data recorded in combination with fMRI. PMID:26151100

Tunable reaction potentials in open framework nanoparticle battery electrodes for grid-scale energy storage.

PubMed

Wessells, Colin D; McDowell, Matthew T; Peddada, Sandeep V; Pasta, Mauro; Huggins, Robert A; Cui, Yi

2012-02-28

The electrical energy grid has a growing need for energy storage to address short-term transients, frequency regulation, and load leveling. Though electrochemical energy storage devices such as batteries offer an attractive solution, current commercial battery technology cannot provide adequate power, and cycle life, and energy efficiency at a sufficiently low cost. Copper hexacyanoferrate and nickel hexacyanoferrate, two open framework materials with the Prussian Blue structure, were recently shown to offer ultralong cycle life and high-rate performance when operated as battery electrodes in safe, inexpensive aqueous sodium ion and potassium ion electrolytes. In this report, we demonstrate that the reaction potential of copper-nickel alloy hexacyanoferrate nanoparticles may be tuned by controlling the ratio of copper to nickel in these materials. X-ray diffraction, TEM energy dispersive X-ray spectroscopy, and galvanostatic electrochemical cycling of copper-nickel hexacyanoferrate reveal that copper and nickel form a fully miscible solution at particular sites in the framework without perturbing the structure. This allows copper-nickel hexacyanoferrate to reversibly intercalate sodium and potassium ions for over 2000 cycles with capacity retentions of 100% and 91%, respectively. The ability to precisely tune the reaction potential of copper-nickel hexacyanoferrate without sacrificing cycle life will allow the development of full cells that utilize the entire electrochemical stability window of aqueous sodium and potassium ion electrolytes.

Stable p-i-n FAPbBr 3 devices with improved efficiency using sputtered ZnO as electron transport layer [Stable p-i-n FAPbBr 3 devices with improved efficiency using sputtered inorganic electron transport layer

DOE PAGES

Subbiah, Anand S.; Agarwal, Sumanshu; Mahuli, Neha; ...

2017-02-10

Here, radio-frequency magnetron sputtering is demonstrated as an effective tool to deposit highly crystalline thin zinc oxide (ZnO) layer directly on perovskite absorber as an electron transport layer (ETL). As an absorber, formamidinium lead tribromide (FAPbBr 3) is fabricated through a modified single-step solution process using hydrogen bromide (HBr) as an additive resulting in complete surface coverage and highly crystalline material. A planar p-i-n device architecture with spin-coated poly-(3,4-ethylenedioxythiophene):poly-styrenesulfonic acid (PEDOT:PSS) as hole transport material (HTM) and sputtered ZnO as ETL results in a short circuit current density of 9.5 mA cm -2 and an open circuit potential of 1.19more » V. Numerical simulations are performed to validate the underlying loss mechanisms. The use of phenyl C 60 butyric acid methyl ester (PCBM) interface layer between FAPbBr 3 and sputter-coated ZnO offers shielding from potential plasma-related interface damage. The modified interface results in a better device efficiency of 8.3% with an open circuit potential of 1.35 V. Such devices offer better stability under continuous illumination under ambient conditions in comparison with the conventional organic ETL (PCBM)-based devices.« less

What drives high flow events in the Swiss Alps? Recent developments in wavelet spectral analysis and their application to hydrology

NASA Astrophysics Data System (ADS)

Schaefli, B.; Maraun, D.; Holschneider, M.

2007-12-01

Extreme hydrological events are often triggered by exceptional co-variations of the relevant hydrometeorological processes and in particular by exceptional co-oscillations at various temporal scales. Wavelet and cross wavelet spectral analysis offers promising time-scale resolved analysis methods to detect and analyze such exceptional co-oscillations. This paper presents the state-of-the-art methods of wavelet spectral analysis, discusses related subtleties, potential pitfalls and recently developed solutions to overcome them and shows how wavelet spectral analysis, if combined to a rigorous significance test, can lead to reliable new insights into hydrometeorological processes for real-world applications. The presented methods are applied to detect potentially flood triggering situations in a high Alpine catchment for which a recent re-estimation of design floods encountered significant problems simulating the observed high flows. For this case study, wavelet spectral analysis of precipitation, temperature and discharge offers a powerful tool to help detecting potentially flood producing meteorological situations and to distinguish between different types of floods with respect to the prevailing critical hydrometeorological conditions. This opens very new perspectives for the analysis of model performances focusing on the occurrence and non-occurrence of different types of high flow events. Based on the obtained results, the paper summarizes important recommendations for future applications of wavelet spectral analysis in hydrology.

Stable p-i-n FAPbBr 3 devices with improved efficiency using sputtered ZnO as electron transport layer [Stable p-i-n FAPbBr 3 devices with improved efficiency using sputtered inorganic electron transport layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Subbiah, Anand S.; Agarwal, Sumanshu; Mahuli, Neha

Here, radio-frequency magnetron sputtering is demonstrated as an effective tool to deposit highly crystalline thin zinc oxide (ZnO) layer directly on perovskite absorber as an electron transport layer (ETL). As an absorber, formamidinium lead tribromide (FAPbBr 3) is fabricated through a modified single-step solution process using hydrogen bromide (HBr) as an additive resulting in complete surface coverage and highly crystalline material. A planar p-i-n device architecture with spin-coated poly-(3,4-ethylenedioxythiophene):poly-styrenesulfonic acid (PEDOT:PSS) as hole transport material (HTM) and sputtered ZnO as ETL results in a short circuit current density of 9.5 mA cm -2 and an open circuit potential of 1.19more » V. Numerical simulations are performed to validate the underlying loss mechanisms. The use of phenyl C 60 butyric acid methyl ester (PCBM) interface layer between FAPbBr 3 and sputter-coated ZnO offers shielding from potential plasma-related interface damage. The modified interface results in a better device efficiency of 8.3% with an open circuit potential of 1.35 V. Such devices offer better stability under continuous illumination under ambient conditions in comparison with the conventional organic ETL (PCBM)-based devices.« less

A concept for a soft gamma-ray concentrator using thin-film multilayer structures

NASA Astrophysics Data System (ADS)

Bloser, Peter F.; Shirazi, Farzane; Echt, Olof; Krzanowski, James E.; Legere, Jason S.; McConnell, Mark L.; Tsavalas, John G.; Wong, Emily N.; Aliotta, Paul H.

2016-07-01

We are investigating the use of thin-film, multilayer structures to form optics capable of concentrating soft gamma rays with energies greater than 100 keV, beyond the reach of current grazing-incidence hard X-ray mirrors. Alternating layers of low- and high-density materials (e.g., polymers and metals) will channel soft gamma-ray photons via total external reflection. A suitable arrangement of bent structures will then concentrate the incident radiation to a point. Gamma-ray optics made in this way offer the potential for soft gamma-ray telescopes with focal lengths of less than 10 m, removing the need for formation flying spacecraft and opening the field up to balloon-borne instruments. Following initial investigations conducted at Los Alamos National Laboratory, we have constructed and tested a prototype structure using spin coating combined with magnetron sputtering. We are now investigating whether it is possible to grow such flexible multi-layer structures with the required thicknesses and smoothness more quickly by using magnetron sputter and pulsed laser deposition techniques. We present the latest results of our fabrication and gamma-ray channeling tests, and describe our modeling of the sensitivity of potential concentrator-based telescope designs. If successful, this technology offers the potential for transformational increases in sensitivity while dramatically improving the system-level performance of future high-energy astronomy missions through reduced mass and complexity.

3D Printing Polymers with Supramolecular Functionality for Biological Applications.

PubMed

Pekkanen, Allison M; Mondschein, Ryan J; Williams, Christopher B; Long, Timothy E

2017-09-11

Supramolecular chemistry continues to experience widespread growth, as fine-tuned chemical structures lead to well-defined bulk materials. Previous literature described the roles of hydrogen bonding, ionic aggregation, guest/host interactions, and π-π stacking to tune mechanical, viscoelastic, and processing performance. The versatility of reversible interactions enables the more facile manufacturing of molded parts with tailored hierarchical structures such as tissue engineered scaffolds for biological applications. Recently, supramolecular polymers and additive manufacturing processes merged to provide parts with control of the molecular, macromolecular, and feature length scales. Additive manufacturing, or 3D printing, generates customizable constructs desirable for many applications, and the introduction of supramolecular interactions will potentially increase production speed, offer a tunable surface structure for controlling cell/scaffold interactions, and impart desired mechanical properties through reinforcing interlayer adhesion and introducing gradients or self-assembled structures. This review details the synthesis and characterization of supramolecular polymers suitable for additive manufacture and biomedical applications as well as the use of supramolecular polymers in additive manufacturing for drug delivery and complex tissue scaffold formation. The effect of supramolecular assembly and its dynamic behavior offers potential for controlling the anisotropy of the printed objects with exquisite geometrical control. The potential for supramolecular polymers to generate well-defined parts, hierarchical structures, and scaffolds with gradient properties/tuned surfaces provides an avenue for developing next-generation biomedical devices and tissue scaffolds.

Sustaining prospective memory functioning in amnestic mild cognitive impairment: A lifespan approach to the critical role of encoding.

PubMed

Pereira, Antonina; Altgassen, Mareike; Atchison, Lesley; de Mendonça, Alexandre; Ellis, Judi

2018-04-16

Prospective memory (PM), the ability to remember to perform future activities, is a fundamental requirement for independent living. PM tasks pervade our daily lives, and PM failures represent one of the most prominent memory concerns across the entire life span. This study aimed to address this issue by exploring the potential benefits of specific encoding strategies on memory for intentions across healthy adulthood and in the early stages of cognitive impairment. PM performance was explored through an experimental paradigm in 96 participants: 32 amnestic mild cognitively impaired patients aged 64-87 years (M = 6.75, SD = 5.88), 32 healthy older adults aged 62-84 years (M = 76.06, SD = 6.03), and 32 younger adults 18-22 years (M = 19.75, SD = 1.16). The potential benefit of the use of enactment (i.e., physically simulating the intended action) at encoding to support an autonomous performance despite neuronal degeneration was assessed. PM was consistently identified as a sensitive and specific indicator of cognitive impairment. Importantly, enacted encoding was consistently beneficial for PM performance of all the participants, but especially so in the case of healthy and cognitively impaired older adults. These positive results have unveiled the potential of this encoding technique to optimize attentional demands through an adaptive allocation of strategic resources across both healthy and cognitively impaired samples. Theoretical implications of this work are discussed as well as the considerable translational potential to improve social well-being. A better understanding of the strategies that can enhance PM offers the potential for cost-effective and widely applicable tools which may support independent living across the adult life span. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Design of sustained release tablet containing fucoidan.

PubMed

Tran, Thao Truong-Dinh; Ngo, Dai Kieu-Phuong; Vo, Toi Van; Tran, Phuong Ha-Lien

2015-01-01

The study introduced a new therapeutic agent, fucoidan, which can offer potential medical treatments including anti-inflammatory and anti-coagulant activities, as well as anti-proliferative effects on cancer cells. Fucoidan was included in sustained release formulations expected for an effective plasma drug concentration for approximately 24 h. The matrices based on the two polymers hydroxypropyl methycellulose (HPMC) and polyethylene oxide (PEO) were prepared with various ratios between the polymers and fucoidan. The dissolution profiles of various matrix tablets performed in enzyme-free simulated intestinal fluid (pH 6.8) for 24 h indicated a higher potential of PEO-based matrix tablets in sustaining release of fucoidan. The swelling and erosion of the tablets were also characterized to elucidate the difference among those dissolution profiles.

The price of palliative care: toward a complete accounting of costs and benefits.

PubMed

Boni-Saenz, Alexander A; Dranove, David; Emanuel, Linda L; Lo Sasso, Anthony T

2005-02-01

In this article, currently accepted standards for cost-benefit analysis of health care interventions are outlined, and a framework to evaluate palliative care within these standards is provided. Recent publications on the economic implications of palliative care are reviewed, which are only the "tip of the iceberg" of the potential costs and benefits. Using this framework, the authors offer guidelines for performing comprehensive cost-benefit analyses of palliative care and conclude that many of the issues beneath the surface may be substantial and deserving of closer scrutiny. Methods for gathering relevant cost-benefit information are detailed, along with potential obstacles to implementation. This approach is applicable to palliative care in general, including palliative care for elders.

Calibration and energy measurement of optically levitated nanoparticle sensors

NASA Astrophysics Data System (ADS)

Hebestreit, Erik; Frimmer, Martin; Reimann, René; Dellago, Christoph; Ricci, Francesco; Novotny, Lukas

2018-03-01

Optically levitated nanoparticles offer enormous potential for precision sensing. However, as for any other metrology device, the absolute measurement performance of a levitated-particle sensor is limited by the accuracy of the calibration relating the measured signal to an absolute displacement of the particle. Here, we suggest and demonstrate calibration protocols for levitated-nanoparticle sensors. Our calibration procedures include the treatment of anharmonicities in the trapping potential, as well as a protocol using a harmonic driving force, which is applicable if the sensor is coupled to a heat bath of unknown temperature. Finally, using the calibration, we determine the center-of-mass temperature of an optically levitated particle in thermal equilibrium from its motion and discuss the optimal measurement time required to determine the said temperature.

Airframe-integrated propulsion system for hypersonic cruise vehicles

NASA Technical Reports Server (NTRS)

Jones, R. A.; Huber, P. W.

1978-01-01

The paper describes a new hydrogen-burning airframe-integrated scramjet concept which offers good potential for efficient hypersonic cruise vehicles. The characteristics of the engine which assure good performance are extensive engine-airframe integration, fixed geometry, low cooling, and control of heat release in the supersonic combustor by mixed modes of fuel injection from the combustor entrance. The present paper describes the concept and presents results from inlet tests, direct-connect combustor tests, and tests of two subscale boiler-plate research engines currently underway under conditions which simulate flight at Mach 4 and 7. It is concluded that this engine concept has the potential for high thrust and efficiency, low drag and weight, low cooling requirement, and application to a wide range of vehicle sizes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barbose, Galen; Wiser, Ryan; Bolinger, Mark

In the U.S., the increasing financial support for customer-sited photovoltaic (PV) systems provided through publicly-funded incentive programs has heightened concerns about the long-term performance of these systems. Given the barriers that customers face to ensuring that their PV systems perform well, and the responsibility that PV incentive programs bear to ensure that public funds are prudently spent, these programs should, and often do, play a critical role in addressing PV system performance. To provide a point of reference for assessing the current state of the art, and to inform program design efforts going forward, we examine the approaches to encouragingmore » PV system performance used by 32 prominent PV incentive programs in the U.S. We identify eight general strategies or groups of related strategies that these programs have used to address factors that affect performance, and describe key implementation details. Based on this review, we then offer recommendations for how PV incentive programs can be effectively designed to mitigate potential performance issues.« less

On the Properties and Design of Organic Light-Emitting Devices

NASA Astrophysics Data System (ADS)

Erickson, Nicholas C.

Organic light-emitting devices (OLEDs) are attractive for use in next-generation display and lighting technologies. In display applications, OLEDs offer a wide emission color gamut, compatibility with flexible substrates, and high power efficiencies. In lighting applications, OLEDs offer attractive features such as broadband emission, high-performance, and potential compatibility with low-cost manufacturing methods. Despite recent demonstrations of near unity internal quantum efficiencies (photons out per electron in), OLED adoption lags conventional technologies, particularly in large-area displays and general lighting applications. This thesis seeks to understand the optical and electronic properties of OLED materials and device architectures which lead to not only high peak efficiency, but also reduced device complexity, high efficiency under high excitation, and optimal white-light emission. This is accomplished through the careful manipulation of organic thin film compositions fabricated via vacuum thermal evaporation, and the introduction of a novel device architecture, the graded-emissive layer (G-EML). This device architecture offers a unique platform to study the electronic properties of varying compositions of organic semiconductors and the resulting device performance. This thesis also introduces an experimental technique to measure the spatial overlap of electrons and holes within an OLED's emissive layer. This overlap is an important parameter which is affected by the choice of materials and device design, and greatly impacts the operation of the OLED at high excitation densities. Using the G-EML device architecture, OLEDs with improved efficiency characteristics are demonstrated, achieving simultaneously high brightness and high efficiency.

Molecular Diagnostic Testing for Aspergillus

PubMed Central

Powers-Fletcher, Margaret V.

2016-01-01

The direct detection of Aspergillus nucleic acid in clinical specimens has the potential to improve the diagnosis of aspergillosis by offering more rapid and sensitive identification of invasive infections than is possible with traditional techniques, such as culture or histopathology. Molecular tests for Aspergillus have been limited historically by lack of standardization and variable sensitivities and specificities. Recent efforts have been directed at addressing these limitations and optimizing assay performance using a variety of specimen types. This review provides a summary of standardization efforts and outlines the complexities of molecular testing for Aspergillus in clinical mycology. PMID:27487954

RF Manipulation and Detection of Protons in the High Performance Antiproton Trap (HiPAT)

NASA Technical Reports Server (NTRS)

Martin, James J.; Lewis, Raymond A.; Pearson, J. Boise; Sims, W. Herb; Chakrabarti, Suman; Fant, Wallace E.; McDonald, Stan

2003-01-01

The significant energy density of matter-antimatter annihilation is attractive to the designers of future space propulsion systems, with the potential to offer a highly compact source of power. Many propulsion concepts exist that could take advantage of matter-antimatter reactions, and current antiproton production rates are sufficient to support basic proof-of-principle evaluation of technology associated with antimatter-derived propulsion. One enabling technology for such experiments is portable storage of low energy antiprotons, allowing antiprotons to be trapped, stored, and transported for use at an experimental facility.

Sol-Gel Processing of MgF₂ Antireflective Coatings.

PubMed

Löbmann, Peer

2018-05-02

There are different approaches for the preparation of porous antireflective λ/4 MgF₂ films from liquid precursors. Among these, the non-aqueous fluorolytic synthesis of precursor solutions offers many advantages in terms of processing simplicity and scalability. In this paper, the structural features and optical performance of the resulting films are highlighted, and their specific interactions with different inorganic substrates are discussed. Due to their excellent abrasion resistance, coatings have a high potential for applications on glass. Using solvothermal treatment of precursor solutions, also the processing of thermally sensitive polymer substrates becomes feasible.

3D MEMS in Standard Processes: Fabrication, Quality Assurance, and Novel Measurement Microstructures

NASA Technical Reports Server (NTRS)

Lin, Gisela; Lawton, Russell A.

2000-01-01

Three-dimensional MEMS microsystems that are commercially fabricated require minimal post-processing and are easily integrated with CMOS signal processing electronics. Measurements to evaluate the fabrication process (such as cross-sectional imaging and device performance characterization) provide much needed feedback in terms of reliability and quality assurance. MEMS technology is bringing a new class of microscale measurements to fruition. The relatively small size of MEMS microsystems offers the potential for higher fidelity recordings compared to macrosize counterparts, as illustrated in the measurement of muscle cell forces.

The brain MRI classification problem from wavelets perspective

NASA Astrophysics Data System (ADS)

Bendib, Mohamed M.; Merouani, Hayet F.; Diaba, Fatma

2015-02-01

Haar and Daubechies 4 (DB4) are the most used wavelets for brain MRI (Magnetic Resonance Imaging) classification. The former is simple and fast to compute while the latter is more complex and offers a better resolution. This paper explores the potential of both of them in performing Normal versus Pathological discrimination on the one hand, and Multiclassification on the other hand. The Whole Brain Atlas is used as a validation database, and the Random Forest (RF) algorithm is employed as a learning approach. The achieved results are discussed and statistically compared.

Interaction between milk allowance and fat content of the starter feed on performance of Holstein calves.

PubMed

Araujo, G; Terré, M; Bach, A

2014-10-01

Sixty-six Holstein male calves [42 ± 6.0 kg of body weight (BW) and 12 ± 3.1 d of age] were housed individually and allocated to 1 of 4 treatments following a 2 × 2 factorial complete randomized design to assess the potential interaction between milk replacer (MR) allowance and fat content in the starter feed. Thus, 4 treatments were evaluated: a low-fat (4.1% fat; LF) starter feed offered along with 4 L/d of MR (4 LF), a high-fat (11.2% fat; HF) starter feed plus 4 L/d of MR (4 HF), a LF starter feed offered with 6 L/d of MR (6LF), and an HF starter feed offered with 6 L/d of MR (6 HF). Calves were fed either 4 or 6 L/d of MR (25% crude protein and 19.2% fat) in 2 offers (0800 and 1630 h) and had ad libitum access to either an LF or an HF starter feed (21.4 and 22.3% crude protein). Calves were weaned at wk 6 of study by halving the daily MR allowance for 1 wk. Individual MR and starter feed intakes were recorded daily and BW was determined weekly. A glucose tolerance test was performed on d 30 of study to evaluate the effects of increased energy provision on glucose metabolism. Apparent feed digestibility was measured for the last 5 d of study. Overall, fat content of starter feed had no effect on solid feed intake. However, during wk 8 of study (after weaning), calves in the LF treatment had greater starter feed intake than HF calves. Calves on 6 L/d of MR had greater BW than calves fed 4 L/d from the second week of study until weaning. After weaning, 6 LF calves had lesser BW than 6 HF calves. Calves on 6 L/d of MR had greater average daily gain than calves fed 4 L/d, and 6 HF calves tended to have the greatest average daily gain. Glucose clearance rate tended to be lesser for HF than for LF calves. In conclusion, offering 6 L/d of MR increased growth performance before weaning and, when offering 6 L/d of MR, feeding a high-fat starter feed resulted in the greatest BW after weaning. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Lean, premixed, prevaporized fuel combustor conceptual design study

NASA Technical Reports Server (NTRS)

Fiorentino, A. J.; Greene, W.; Kim, J.

1979-01-01

Four combustor concepts, designed for the energy efficient engine, utilize variable geometry or other flow modulation techniques to control the equivalence ratio of the initial burning zone. Lean conditions are maintained at high power to control oxides of nitrogen while near stoichometric conditions are maintained at low power for low CO and THC emissions. Each concept was analyzed and ranked for its potential in meeting the goals of the program. Although the primary goal of the program is a low level of nitric oxide emissions at stratospheric cruise conditions, both the ground level EPA emission standards and combustor performance and operational requirements typical of advanced subsonic aircraft engines are retained as goals as well. Based on the analytical projections made, two of the concepts offer the potential of achieving the emission goals; however, the projected operational characteristics and reliability of any concept to perform satisfactorily over an entire aircraft flight envelope would require extensive experimental substantiation before engine adaptation can be considered.

Systematic Sustainability Assessment (SSA) Tool for Hydroelectric Project in Malaysia

NASA Astrophysics Data System (ADS)

Turan, Faiz Mohd; Johan, Kartina

2017-08-01

Sustainably developed and managed hydropower has enormous potential to contribute to global sustainability goals. It is known that hydroelectricity contributing small amounts to greenhouse gas emissions and other atmospheric pollutants. However, developing the remaining hydroelectric potential offers many challenges, and public pressure and expectations on the environmental and social performance of hydroelectric tend to increase over time. This paper aims to develop Systematic Sustainability Assessment (SSA) Tool that promotes and guides more sustainable hydroelectric projects in the context of Malaysia. The proposed SSA tool which not only provide a quality and quantitative report of sustainability performance but also act as Self-Assessment Report (SAR) to provide roadmap to achieve greater level of sustainability in project management for continuous improvement. It is expected to provide a common language that allow government, civil society, financial institutions and the hydroelectric sector to talk about and evaluate sustainability issues. The advantage of SSA tool is it can be used at any stage of hydroelectric development, from the earliest planning stages right through to operation.

Open-Circuit Voltage Deficit, Radiative Sub-Bandgap States, and Prospects in Quantum Dot Solar Cells

PubMed Central

Chuang, Chia-Hao Marcus; Maurano, Andrea; Brandt, Riley E.; Hwang, Gyu Weon; Jean, Joel; Buonassisi, Tonio; Bulović, Vladimir; Bawendi, Moungi G.

2016-01-01

Quantum dot photovoltaics (QDPV) offer the potential for low-cost solar cells. To develop strategies for continued improvement in QDPVs, a better understanding of the factors that limit their performance is essential. Here, we study carrier recombination processes that limit the power conversion efficiency of PbS QDPVs. We demonstrate the presence of radiative sub-bandgap states and sub-bandgap state filling in operating devices by using photoluminescence (PL) and electroluminescence (EL) spectroscopy. These sub-bandgap states are most likely the origin of the high open-circuit-voltage (VOC) deficit and relatively limited carrier collection that have thus far been observed in QDPVs. Combining these results with our perspectives on recent progress in QDPV, we conclude that eliminating sub-bandgap states in PbS QD films has the potential to show a greater gain than may be attainable by optimization of interfaces between QDs and other materials. We suggest possible future directions that could guide the design of high-performance QDPVs. PMID:25927871

A Virtual Geant4 Environment

NASA Astrophysics Data System (ADS)

Iwai, Go

2015-12-01

We describe the development of an environment for Geant4 consisting of an application and data that provide users with a more efficient way to access Geant4 applications without having to download and build the software locally. The environment is platform neutral and offers the users near-real time performance. In addition, the environment consists of data and Geant4 libraries built using low-level virtual machine (LLVM) tools which can produce bitcode that can be embedded in HTML and accessed via a browser. The bitcode is downloaded to the local machine via the browser and can then be configured by the user. This approach provides a way of minimising the risk of leaking potentially sensitive data used to construct the Geant4 model and application in the medical domain for treatment planning. We describe several applications that have used this approach and compare their performance with that of native applications. We also describe potential user communities that could benefit from this approach.

Study of ground state optical transfer for ultracold alkali dimers

NASA Astrophysics Data System (ADS)

Bouloufa-Maafa, Nadia; Londono, Beatriz; Borsalino, Dimitri; Vexiau, Romain; Mahecha, Jorge; Dulieu, Olivier; Luc-Koenig, Eliane

2013-05-01

Control of molecular states by laser pulses offer promising potential applications. The manipulation of molecules by external fields requires precise knowledge of the molecular structure. Our motivation is to perform a detailed analysis of the spectroscopic properties of alkali dimers, with the aim to determine efficient optical paths to form molecules in the absolute ground state and to determine the optimal parameters of the optical lattices where those molecules are manipulated to avoid losses by collisions. To this end, we use state of the art molecular potentials, R-dependent spin-orbit coupling and transition dipole moment to perform our calculations. R-dependent SO coupling are of crucial importance because the transitions occur at internuclear distances where they are affected by this R-dependence. Efficient schemes to transfer RbCs, KRb and KCs to the absolute ground state as well as the optimal parameters of the optical lattices will be presented. This work was supported in part by ``Triangle de la Physique'' under contract 2008-007T-QCCM (Quantum Control of Cold Molecules).

Electrodeposition of Rhodium Nanowires Arrays and Their Morphology-Dependent Hydrogen Evolution Activity

PubMed Central

Zhang, Liqiu; Liu, Lichun; Wang, Hongdan; Shen, Hongxia; Cheng, Qiong; Yan, Chao; Park, Sungho

2017-01-01

This work reports on the electrodeposition of rhodium (Rh) nanowires with a controlled surface morphology synthesized using an anodic aluminum oxide (AAO) template. Vertically aligned Rh nanowires with a smooth and coarse morphology were successfully deposited by adjusting the electrode potential and the concentration of precursor ions and by involving a complexing reagent in the electrolyte solution. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses were used to follow the morphological evolution of Rh nanowires. As a heterogeneous electrocatalyst for hydrogen evolution reactions (HER), the coarse Rh nanowire array exhibited an enhanced catalytic performance respect to smooth ones due to the larger surface area to mass ratio and the higher density of catalytically active defects, as evidenced by voltammetric measurements and TEM. Results suggest that the morphology of metallic nanomaterials could be readily engineered by electrodeposition. The controlled electrodeposition offers great potential for the development of an effective synthesis tool for heterogeneous catalysts with a superior performance for wide applications. PMID:28467375

Change detection on UGV patrols with respect to a reference tour using VIS imagery

NASA Astrophysics Data System (ADS)

Müller, Thomas

2015-05-01

Autonomous driving robots (UGVs, Unmanned Ground Vehicles) equipped with visual-optical (VIS) cameras offer a high potential to automatically detect suspicious occurrences and dangerous or threatening situations on patrol. In order to explore this potential, the scene of interest is recorded first on a reference tour representing the 'everything okay' situation. On further patrols changes are detected with respect to the reference in a two step processing scheme. In the first step, an image retrieval is done to find the reference images that are closest to the current camera image on patrol. This is done efficiently based on precalculated image-to-image registrations of the reference by optimizing image overlap in a local reference search (after a global search when that is needed). In the second step, a robust spatio-temporal change detection is performed that widely compensates 3-D parallax according to variations of the camera position. Various results document the performance of the presented approach.

Graded porous polyurethane foam: a potential scaffold for oro-maxillary bone regeneration.

PubMed

Giannitelli, S M; Basoli, F; Mozetic, P; Piva, P; Bartuli, F N; Luciani, F; Arcuri, C; Trombetta, M; Rainer, A; Licoccia, S

2015-06-01

Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesion, migration, and proliferation, while inferring suitable mechanical properties to the construct. In the present study, polyurethane (PU) foams were synthesized to develop a graded porous material-characterized by a dense shell and a porous core-for the treatment of oro-maxillary bone defects. Foam was synthesized via a one-pot reaction starting from a polyisocyanate and a biocompatible polyester diol, using water as a foaming agent. Different foaming conditions were examined, with the aim of creating a dense/porous functional graded material that would perform at the same time as an osteoconductive scaffold for bone defect regeneration and as a membrane-barrier to gingival tissue ingrowth. The obtained PU was characterized in terms of morphological and mechanical properties. Biocompatibility assessment was performed in combination with bone-marrow-derived human mesenchymal stromal cells (hBMSCs). Our findings confirm that the material is potentially suitable for guided bone regeneration applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Perspective: Machine learning potentials for atomistic simulations

NASA Astrophysics Data System (ADS)

Behler, Jörg

2016-11-01

Nowadays, computer simulations have become a standard tool in essentially all fields of chemistry, condensed matter physics, and materials science. In order to keep up with state-of-the-art experiments and the ever growing complexity of the investigated problems, there is a constantly increasing need for simulations of more realistic, i.e., larger, model systems with improved accuracy. In many cases, the availability of sufficiently efficient interatomic potentials providing reliable energies and forces has become a serious bottleneck for performing these simulations. To address this problem, currently a paradigm change is taking place in the development of interatomic potentials. Since the early days of computer simulations simplified potentials have been derived using physical approximations whenever the direct application of electronic structure methods has been too demanding. Recent advances in machine learning (ML) now offer an alternative approach for the representation of potential-energy surfaces by fitting large data sets from electronic structure calculations. In this perspective, the central ideas underlying these ML potentials, solved problems and remaining challenges are reviewed along with a discussion of their current applicability and limitations.

Online availability and safety of drugs in shortage: a descriptive study of internet vendor characteristics.

PubMed

Liang, Bryan A; Mackey, Tim K

2012-02-09

Unprecedented drug shortages announced by the US Food and Drug Administration (FDA) have severely affected therapeutic access, patient safety, and public health. With continued shortages, patients may seek drugs online. To assess the prevalence of online marketing for current FDA shortage drugs and potential patient safety risks. We performed a descriptive study of the prevalence of online marketing for shortage drugs-that is, offers for sale of each drug, including characteristics of online drug sellers and intermediary sites marketing these drugs. Of the 72 FDA shortage-listed drugs, 68 (94%) were offered for sale online. We found 291 offers for these drugs, the vast majority (n = 207, 71.1%) by online drug sellers selling direct to consumers. Intermediary sites included data aggregators (n = 22, 8%), forum links (n = 23, 8%), and personal page data links (n = 34, 12%), as well as Flickr social media links (n = 5, 2%), all advertising drugs without a prescription. Of the 91 online drug sellers identified, 31 (34%) had more than 1 shortage drug offered for sale, representing most (n = 148, 71%) of all online drug seller sales offers. The majority of these online drug sellers (n = 21, 68%) were on the National Association of Boards of Pharmacy (NABP) Not Recommended Sites list. Finally, for shortage drugs with an online drug seller (n = 58, 85%), 53 (91%) had at least one site on the Not Recommended list and 21 (36%) had only sites on the Not Recommended list. FDA shortage drugs are widely marketed over the Internet. Suspect online drug sellers and intermediaries dominate these sales offers. As a critical risk management issue, patients, providers, and policymakers should be extremely cautious in procuring shortage drugs through Internet sourcing.

Online Availability and Safety of Drugs in Shortage: A Descriptive Study of Internet Vendor Characteristics

PubMed Central

Mackey, Tim K

2012-01-01

Background Unprecedented drug shortages announced by the US Food and Drug Administration (FDA) have severely affected therapeutic access, patient safety, and public health. With continued shortages, patients may seek drugs online. Objective To assess the prevalence of online marketing for current FDA shortage drugs and potential patient safety risks. Methods We performed a descriptive study of the prevalence of online marketing for shortage drugs—that is, offers for sale of each drug, including characteristics of online drug sellers and intermediary sites marketing these drugs. Results Of the 72 FDA shortage-listed drugs, 68 (94%) were offered for sale online. We found 291 offers for these drugs, the vast majority (n = 207, 71.1%) by online drug sellers selling direct to consumers. Intermediary sites included data aggregators (n = 22, 8%), forum links (n = 23, 8%), and personal page data links (n = 34, 12%), as well as Flickr social media links (n = 5, 2%), all advertising drugs without a prescription. Of the 91 online drug sellers identified, 31 (34%) had more than 1 shortage drug offered for sale, representing most (n = 148, 71%) of all online drug seller sales offers. The majority of these online drug sellers (n = 21, 68%) were on the National Association of Boards of Pharmacy (NABP) Not Recommended Sites list. Finally, for shortage drugs with an online drug seller (n = 58, 85%), 53 (91%) had at least one site on the Not Recommended list and 21 (36%) had only sites on the Not Recommended list. Conclusions FDA shortage drugs are widely marketed over the Internet. Suspect online drug sellers and intermediaries dominate these sales offers. As a critical risk management issue, patients, providers, and policymakers should be extremely cautious in procuring shortage drugs through Internet sourcing. PMID:22321731

SAW Synthesis With IDTs Array and the Inverse Filter: Toward a Versatile SAW Toolbox for Microfluidics and Biological Applications.

PubMed

Riaud, Antoine; Baudoin, Michael; Thomas, Jean-Louis; Bou Matar, Olivier

2016-10-01

Surface acoustic waves (SAWs) are versatile tools to manipulate fluids at small scales for microfluidics and biological applications. A nonexhaustive list of operations that can be performed with SAW includes sessile droplet displacement, atomization, division, and merging but also the actuation of fluids embedded in microchannels or the manipulation of suspended particles. However, each of these operations requires a specific design of the wave generation system, the so-called interdigitated transducers (IDTs). Depending on the application, it might indeed be necessary to generate focused or plane, propagating or standing, and aligned or shifted waves. Furthermore, the possibilities offered by more complex wave fields such as acoustical vortices for particle tweezing and liquid twisting cannot be explored with classical IDTs. In this paper, we show that the inverse filter technique coupled with an IDTs array enables us to synthesize all classical wave fields used in microfluidics and biological applications with a single multifunctional platform. It also enables us to generate swirling SAWs, whose potential for the on-chip synthesis of tailored acoustical vortices has been demonstrated lately. The possibilities offered by this platform are illustrated by performing many operations successively on sessile droplets with the same system.

Becoming a psychiatric/mental health nurse in the UK: a qualitative study exploring processes of identity formation.

PubMed

Hurley, John; Lakeman, Richard

2011-01-01

Identity studies are well established across the social science literature with mental health nursing beginning to offer evidenced insights into what may, or may not, constitute key identity performances. For mental health nursing these performances remain contested, both from within the profession and from international contexts that favour generic constructions of mental health. This paper offers findings from a qualitative study that focused upon the process of how mental health nursing identity development is influenced, rather than what that identity may or may not be. These findings highlight that mental health nurses (MHNs) not only form their identity around service user centred education and training, but that many also use the education as a means to leave the profession. Through highlighting the impact of informal education (i.e., through work), formal education, and training upon the formation of mental health nursing identity, nurses are potentially alerted to the importance of clinically focussed mental health being prominent within curricula, rewarding mental health nursing skills specialisation, and the importance of the role of the service user in mental health nurse education and, hence, identity formation.

Military-specific application of nutritional supplements: a brief overview.

PubMed

Hoedebecke, Kyle; Brink, Will

2015-01-01

The Soldiers of America's military endure numerous physical and mental challenges that demand strict physical fitness regimens, extreme mental agility, and a perpetual readiness to deploy at a moment's notice. The chronicity of these stressors has the potential to dramatically reduce performance - both directly and indirectly.  Because of this risk, many Soldiers turn to nutritional supplements with hopes of optimizing performance. Increasing amounts of research have demonstrated that various supplements may enhance overall physical prowess, health, and offer quicker recovery in the face of corporal or psychological extremes. Most individuals, including many medical and nutrition professionals, possess only an elementary comprehension of nutritional supplements and their effect on Soldiers in training or combat environments. Nevertheless, a grasp of these details is required for safety and optimal benefits. Various compounds have been evaluated - to include evidence within the military setting - and found to augment endurance, increase cognitive function, decrease knee pain, or offer hearing or lung protection in the face of high-energy impulses. These efficacious outcomes may serve to augment the health and longevity of these Soldiers; however, continued research is needed for efficacy and long-term safety within specific environments.

A Near-Term, High-Confidence Heavy Lift Launch Vehicle

NASA Technical Reports Server (NTRS)

Rothschild, William J.; Talay, Theodore A.

2009-01-01

The use of well understood, legacy elements of the Space Shuttle system could yield a near-term, high-confidence Heavy Lift Launch Vehicle that offers significant performance, reliability, schedule, risk, cost, and work force transition benefits. A side-mount Shuttle-Derived Vehicle (SDV) concept has been defined that has major improvements over previous Shuttle-C concepts. This SDV is shown to carry crew plus large logistics payloads to the ISS, support an operationally efficient and cost effective program of lunar exploration, and offer the potential to support commercial launch operations. This paper provides the latest data and estimates on the configurations, performance, concept of operations, reliability and safety, development schedule, risks, costs, and work force transition opportunities for this optimized side-mount SDV concept. The results presented in this paper have been based on established models and fully validated analysis tools used by the Space Shuttle Program, and are consistent with similar analysis tools commonly used throughout the aerospace industry. While these results serve as a factual basis for comparisons with other launch system architectures, no such comparisons are presented in this paper. The authors welcome comparisons between this optimized SDV and other Heavy Lift Launch Vehicle concepts.

Glaucoma and cataract surgery: two roads merging into one.

PubMed

Shah, Manjool; Law, Geoffrey; Ahmed, Iqbal Ike K

2016-01-01

To discuss the increasing utilization of cataract extraction in the management of glaucoma and to highlight advances in surgical care that can promote synergistic treatment of these comorbid conditions. Recent years have demonstrated significant advances in the management of glaucoma through the use of novel microinvasive glaucoma devices. Furthermore, an increased understanding of the role of cataract surgery in the treatment of various glaucomas warrants review. Nevertheless, cataract surgery in the glaucoma patient warrants specific preoperative, intraoperative, and postoperative planning to optimize visual function and quality of life while mitigating potential risk factors for adverse events. Although the challenges of performing cataract extraction on glaucoma patients exist, the potential benefit to these patients is substantial. With attention to pre- and perioperative surgical planning and intraoperative technique, as well as with awareness and potential utilization of novel devices and treatment strategies, cataract extraction offers a unique platform for anatomical and functional improvement in this increasingly common cohort of patients.

Automatic Parametrization of Somatosensory Evoked Potentials With Chirp Modeling.

PubMed

Vayrynen, Eero; Noponen, Kai; Vipin, Ashwati; Thow, X Y; Al-Nashash, Hasan; Kortelainen, Jukka; All, Angelo

2016-09-01

In this paper, an approach using polynomial phase chirp signals to model somatosensory evoked potentials (SEPs) is proposed. SEP waveforms are assumed as impulses undergoing group velocity dispersion while propagating along a multipath neural connection. Mathematical analysis of pulse dispersion resulting in chirp signals is performed. An automatic parameterization of SEPs is proposed using chirp models. A Particle Swarm Optimization algorithm is used to optimize the model parameters. Features describing the latencies and amplitudes of SEPs are automatically derived. A rat model is then used to evaluate the automatic parameterization of SEPs in two experimental cases, i.e., anesthesia level and spinal cord injury (SCI). Experimental results show that chirp-based model parameters and the derived SEP features are significant in describing both anesthesia level and SCI changes. The proposed automatic optimization based approach for extracting chirp parameters offers potential for detailed SEP analysis in future studies. The method implementation in Matlab technical computing language is provided online.

Feasibility Study of Economics and Performance of Solar Photovoltaics at the Stringfellow Superfund Site in Riverside, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mosey, G.; Van Geet, O.

2010-12-01

This report presents the results of an assessment of the technical and economic feasibility of deploying a photovoltaics (PV) system on the Stringfellow Superfund Site in Riverside, California. The site was assessed for possible PV installations. The cost, performance, and site impacts of different PV options were estimated. The economics of the potential systems were analyzed using an electric rate of $0.13/kWh and incentives offered by Southern California Edison under the California Solar Initiative. According to the assessment, a government-owned, ground-mounted PV system represents a technically and economically feasible option. The report recommends financing options that could assist in themore » implementation of such a system.« less

Group-level issues in the design and training of cockpit crews

NASA Technical Reports Server (NTRS)

Hackman, J. Richard

1987-01-01

Cockpit crews always operate in an organizational context, and the transactions between the crew and representatives of that context (e.g., organizational managers, air traffic controllers) are consequential for any crew's performance. For a complete understanding of crew performance a look beyond the traditional focus on individual pilots is provided to see how team- and organization-level factors can enhance (or impede) the ability of even well-trained individuals to work together effectively. This way of thinking about cockpit crews (that is, viewing them as teams that operate in organizations) offers some potentially useful avenues for thinking about next steps in the development of CRM training programs. Those possibilities are explored, emphasizing how they can enrich (not replace) individually-focussed CRM training.

Parallel tempering for the traveling salesman problem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Percus, Allon; Wang, Richard; Hyman, Jeffrey

We explore the potential of parallel tempering as a combinatorial optimization method, applying it to the traveling salesman problem. We compare simulation results of parallel tempering with a benchmark implementation of simulated annealing, and study how different choices of parameters affect the relative performance of the two methods. We find that a straightforward implementation of parallel tempering can outperform simulated annealing in several crucial respects. When parameters are chosen appropriately, both methods yield close approximation to the actual minimum distance for an instance with 200 nodes. However, parallel tempering yields more consistently accurate results when a series of independent simulationsmore » are performed. Our results suggest that parallel tempering might offer a simple but powerful alternative to simulated annealing for combinatorial optimization problems.« less

Increased illumination uniformity and reduced photodamage offered by the Lissajous scanning in fiber-optic two-photon endomicroscopy

NASA Astrophysics Data System (ADS)

Liang, Wenxuan; Murari, Kartikeya; Zhang, Yuying; Chen, Yongping; Li, Ming-Jun; Li, Xingde

2012-02-01

We compare the illumination uniformity and the associated effects of the spiral and Lissajous scanning patterns that are commonly used in an endomicroscope. Theoretical analyses and numerical simulations were first performed to quantitatively investigate the area illumination density in the spiral scanning pattern. The results revealed the potential problem of manifest photodamage due to the very high illumination density in the center of the spiral scan. Similar analyses of the Lissajous scanning pattern, which can be conveniently implemented on the same endomicroscope with no hardware modifications, showed a more uniform illumination density with about an 80-fold reduction in the peak illumination density. To underscore the benefit offered by the improved illumination uniformity, we conducted in vitro two-photon fluorescence imaging of cultured cells stained with a LIVE/DEAD viability assay using our home-built, fiber-optic, two-channel endomicroscopy system. Both the spiral and the Lissajous scans were implemented. Our experimental results showed that cells near the spiral scan center experienced obvious photodamage, whereas cells remained alive over the entire region under the Lissajous beam scanning, confirming the predicted advantage offered by the Lissajous scan over this spiral scan in an endomicroscopy setting.

Is robotic surgery cost-effective: yes.

PubMed

Liberman, Daniel; Trinh, Quoc-Dien; Jeldres, Claudio; Zorn, Kevin C

2012-01-01

With the expanding use of new technology in the treatment of clinically localized prostate cancer (PCa), the financial burden on the healthcare system and the individual has been important. Robotics offer many potential advantages to the surgeon and the patient. We assessed the potential cost-effectiveness of robotics in urological surgery and performed a comparative cost analysis with respect to other potential treatment modalities. The direct and indirect costs of purchasing, maintaining, and operating the robot must be compared to alternatives in treatment of localized PCa. Some expanding technologies including intensity-modulated radiation therapy are significantly more expensive than robotic surgery. Furthermore, the benefits of robotics including decreased length of stay and return to work are considerable and must be measured when evaluating its cost-effectiveness. Robot-assisted laparoscopic surgery comes at a high cost but can become cost-effective in mostly high-volume centers with high-volume surgeons. The device when utilized to its maximum potential and with eventual market-driven competition can become affordable.

LOX/LH2 vane pump for auxiliary propulsion systems

NASA Technical Reports Server (NTRS)

Hemminger, J. A.; Ulbricht, T. E.

1985-01-01

Positive displacement pumps offer potential efficiency advantages over centrifugal pumps for future low thrust space missions. Low flow rate applications, such as space station auxiliary propulsion or dedicated low thrust orbiter transfer vehicles, are typical of missions where low flow and high head rise challenge centrifugal pumps. The positive displacement vane pump for pumping of LOX and LH2 is investigated. This effort has included: (1) a testing program in which pump performance was investigated for differing pump clearances and for differing pump materials while pumping LN2, LOX, and LH2; and (2) an analysis effort, in which a comprehensive pump performance analysis computer code was developed and exercised. An overview of the theoretical framework of the performance analysis computer code is presented, along with a summary of analysis results. Experimental results are presented for pump operating in liquid nitrogen. Included are data on the effects on pump performance of pump clearance, speed, and pressure rise. Pump suction performance is also presented.

Performance Evaluation of a UWB-RFID System for Potential Space Applications

NASA Technical Reports Server (NTRS)

Phan, Chan T.; Arndt, D.; Ngo, P.; Gross, J.; Ni, Jianjun; Rafford, Melinda

2006-01-01

This talk presents a brief overview of the ultra-wideband (UWB) RFID system with emphasis on the performance evaluation of a commercially available UWB-RFID system. There are many RFID systems available today, but many provide just basic identification for auditing and inventory tracking. For applications that require high precision real time tracking, UWB technology has been shown to be a viable solution. The use of extremely short bursts of RF pulses offers high immunity to interference from other RF systems, precise tracking due to sub-nanosecond time resolution, and robust performance in multipath environments. The UWB-RFID system Sapphire DART (Digital Active RFID & Tracking) will be introduced in this talk. Laboratory testing using Sapphire DART is performed to evaluate its capability such as coverage area, accuracy, ease of operation, and robustness. Performance evaluation of this system in an operational environment (a receiving warehouse) for inventory tracking is also conducted. Concepts of using the UWB-RFID technology to track astronauts and assets are being proposed for space exploration.

48 CFR 252.225-7003 - Report of intended performance outside the United States and Canada-Submission with offer.

Code of Federal Regulations, 2011 CFR

2011-10-01

... and Canada—Submission With Offer (OCT 2010) (a) Definition. United States, as used in this provision..., Report of Contract Performance Outside the United States; or (2) A computer-generated report that...

48 CFR 252.225-7003 - Report of intended performance outside the United States and Canada-Submission with offer.

Code of Federal Regulations, 2010 CFR

2010-10-01

... and Canada—Submission With Offer (OCT 2010) (a) Definition. United States, as used in this provision..., Report of Contract Performance Outside the United States; or (2) A computer-generated report that...

48 CFR 252.225-7003 - Report of intended performance outside the United States and Canada-Submission with offer.

Code of Federal Regulations, 2013 CFR

2013-10-01

... and Canada—Submission With Offer (OCT 2010) (a) Definition. United States, as used in this provision..., Report of Contract Performance Outside the United States; or (2) A computer-generated report that...

48 CFR 252.225-7003 - Report of intended performance outside the United States and Canada-Submission with offer.

Code of Federal Regulations, 2012 CFR

2012-10-01

... and Canada—Submission With Offer (OCT 2010) (a) Definition. United States, as used in this provision..., Report of Contract Performance Outside the United States; or (2) A computer-generated report that...

Rx for low cash yields.

PubMed

Tobe, Chris

2003-10-01

Certain strategies can offer not-for-profit hospitals potentially greater investment yields while maintaining stability and principal safety. Treasury inflation-indexed securities can offer good returns, low volatility, and inflation protection. "Enhanced cash" strategies offer liquidity and help to preserve capital. Stable value "wrappers" allow hospitals to pursue higher-yielding fixed-income securities without an increase in volatility.

Advances in Single and Multijunction III-V Photovoltaics on Silicon for Space Power

NASA Technical Reports Server (NTRS)

Wilt, David M.; Fitzgerald, Eugene A.; Ringel, Steven A.

2005-01-01

A collaborative research effort at MIT, Ohio State University and NASA has resulted in the demonstration of record quality gallium arsenide (GaAs) based single junction photovoltaic devices on silicon (Si) substrates. The ability to integrate highly efficient, radiation hard III-V based devices on silicon offers the potential for dramatic reductions in cell mass (approx.2x) and increases in cell area. Both of these improvements offer the potential for dramatic reductions in the cost of on-orbit electrical power. Recently, lattice matched InGaP/GaAs and metamorphic InGaP/InGaAs dual junction solar cells were demonstrated by MBE and OMVPE, respectively. Single junction GaAs on Si devices have been integrated into a space flight experiment (MISSES), scheduled to be launched to the International Space Station in March of 2005. I-V performance data from the GaAs/Si will be collected on-orbit and telemetered to ground stations daily. Microcracks in the GaAs epitaxial material, generated because of differences in the thermal expansion coefficient between GaAs and Si, are of concern in the widely varying thermal environment encountered in low Earth orbit. Ground based thermal life cycling (-80 C to + 80 C) equivalent to 1 year in LEO has been conducted on GaAs/Si devices with no discernable degradation in device performance, suggesting that microcracks may not limit the ability to field GaAs/Si in harsh thermal environments. Recent advances in the development and testing of III-V photovoltaic devices on Si will be presented.

Comparison of Bone Preserving and Radical Surgical Treatment in 32 Cases of Calcaneal Osteomyelitis.

PubMed

Babiak, Ireneusz; Pędzisz, Piotr; Kulig, Mateusz; Janowicz, Jakub; Małdyk, Paweł

2016-01-01

Introduction. Radical procedures like calcanectomy and amputation performed for calcaneal osteomyelitis are regarded as effective in eradication of infection even though potentially functionally disabling. Bone sparing procedures offer better functional result at the expense of potentially worse infection control. The aim of the study has been to assess the influence of the surgical radicalism as much as the extent of bone infection on the final outcome in the surgical therapy of chronic calcaneal osteomyelitis (CO). Material and method. 32 patients with chronic CO have comprised the group under study: 8 with superficial type, 12 localised type and 12 with diffuse type according to Cierny-Mader classification. The aim of the treatment was to heal infection, preserve the heel shape and achieve good skin coverage over the calcaneus. The therapy consisted of 9 debridement surgeries with or without flaps, 8 drilling-operations of the calcaneus with application of collagen-gentamicin-sponge in bore holes, 15 partial and 2 total calcanectomies, and 4 below-the knee amputations. Results. The healing of infection and wound has been achieved after 7 of 9 debridements, 6 of 8 drilling-operations, 13 of 15 partial and all total calcanectomies. Conclusion. Bone preserving operations in chronic calcaneal osteomyelitis provided inferior infection control (76,47% vs 88,24%) and worse patient satisfaction (88,24% vs 100%) and almost camparable ambulation (100% vs 93,33%). Drilling of the calcaneus with application of collagen sponge containing gentamicin performed in chronic diffuse calcaneal osteomyelitis seems to offer a viable alternative to partial or radical calcanectomy. V.

Comparison of Bone Preserving and Radical Surgical Treatment in 32 Cases of Calcaneal Osteomyelitis

PubMed Central

Babiak, Ireneusz; Pędzisz, Piotr; Kulig, Mateusz; Janowicz, Jakub; Małdyk, Paweł

2016-01-01

Introduction. Radical procedures like calcanectomy and amputation performed for calcaneal osteomyelitis are regarded as effective in eradication of infection even though potentially functionally disabling. Bone sparing procedures offer better functional result at the expense of potentially worse infection control. The aim of the study has been to assess the influence of the surgical radicalism as much as the extent of bone infection on the final outcome in the surgical therapy of chronic calcaneal osteomyelitis (CO). Material and method. 32 patients with chronic CO have comprised the group under study: 8 with superficial type, 12 localised type and 12 with diffuse type according to Cierny-Mader classification. The aim of the treatment was to heal infection, preserve the heel shape and achieve good skin coverage over the calcaneus. The therapy consisted of 9 debridement surgeries with or without flaps, 8 drilling-operations of the calcaneus with application of collagen-gentamicin-sponge in bore holes, 15 partial and 2 total calcanectomies, and 4 below-the knee amputations. Results. The healing of infection and wound has been achieved after 7 of 9 debridements, 6 of 8 drilling-operations, 13 of 15 partial and all total calcanectomies. Conclusion. Bone preserving operations in chronic calcaneal osteomyelitis provided inferior infection control (76,47% vs 88,24%) and worse patient satisfaction (88,24% vs 100%) and almost camparable ambulation (100% vs 93,33%). Drilling of the calcaneus with application of collagen sponge containing gentamicin performed in chronic diffuse calcaneal osteomyelitis seems to offer a viable alternative to partial or radical calcanectomy. Level of evidence: V. PMID:28529846

Novel Low-Cost, Low-Power Miniature Thermionic Cathode Developed for Microwave/Millimeter Wave Tube and Cathode Ray Tube Applications

NASA Technical Reports Server (NTRS)

Wintucky, Edwin G.

1999-01-01

A low cost, small size and mass, low heater power, durable high-performance barium dispenser thermionic cathode has been developed that offers significant advancements in the design, manufacture, and performance of the electron sources used in vacuum electronic devices--such as microwave (and millimeter wave) traveling-wave tubes (TWT's)--and in display devices such as high-brightness, high-resolution cathode ray tubes (CRT's). The lower cathode heater power and the reduced size and mass of the new cathode are expected to be especially beneficial in TWT's for deep space communications, where future missions are requiring smaller spacecraft, higher data transfer rates (higher frequencies and radiofrequency output power), and greater electrical efficiency. Also expected to benefit are TWT's for commercial and government communication satellites, for both low and geosynchronous Earth orbit, with additional benefits offered by lower cost and potentially higher cathode current loading. A particularly important TWT application is in the microwave power module (MPM), which is a hybrid microwave (or millimeter wave) amplifier consisting of a low-noise solid state driver, a vacuum power booster (small TWT), and an electronic power conditioner integrated into a single compact package. The attributes of compactness and potentially high electrical efficiency make the MPM very attractive for many commercial and government (civilian and defense) applications in communication and radar systems. The MPM is already finding application in defense electronic systems and is under development by NASA for deep space communications. However, for the MPM to become competitive and commercially successful, a major reduction in cost must be achieved.

Is it time to turn our attention toward central mechanisms for post-exertional recovery strategies and performance?

PubMed Central

Rattray, Ben; Argus, Christos; Martin, Kristy; Northey, Joseph; Driller, Matthew

2015-01-01

Key Points Central fatigue is accepted as a contributor to overall athletic performance, yet little research directly investigates post-exercise recovery strategies targeting the brainCurrent post-exercise recovery strategies likely impact on the brain through a range of mechanisms, but improvements to these strategies is neededResearch is required to optimize post-exercise recovery with a focus on the brain Post-exercise recovery has largely focused on peripheral mechanisms of fatigue, but there is growing acceptance that fatigue is also contributed to through central mechanisms which demands that attention should be paid to optimizing recovery of the brain. In this narrative review we assemble evidence for the role that many currently utilized recovery strategies may have on the brain, as well as potential mechanisms for their action. The review provides discussion of how common nutritional strategies as well as physical modalities and methods to reduce mental fatigue are likely to interact with the brain, and offer an opportunity for subsequent improved performance. We aim to highlight the fact that many recovery strategies have been designed with the periphery in mind, and that refinement of current methods are likely to provide improvements in minimizing brain fatigue. Whilst we offer a number of recommendations, it is evident that there are many opportunities for improving the research, and practical guidelines in this area. PMID:25852568

Michigan's Physician Group Incentive Program offers a regional model for incremental 'fee for value' payment reform.

PubMed

Share, David A; Mason, Margaret H

2012-09-01

Blue Cross Blue Shield of Michigan partnered with providers across the state to create an innovative, "fee for value" physician incentive program that would deliver high-quality, efficient care. The Physician Group Incentive Program rewards physician organizations-formal groups of physicians and practices that can accept incentive payments on behalf of their members-based on the number of quality and utilization measures they adopt, such as generic drug dispensing rates, and on their performance on these measures across their patient populations. Physicians also receive payments for implementing a range of patient-centered medical home capabilities, such as patient registries, and they receive higher fees for office visits for incorporating these capabilities into routine practice while also improving performance. Taken together, the incentive dollars, fee increases, and care management payments amount to a potential increase in reimbursement of 40 percent or more from Blue Cross Blue Shield of Michigan for practices designated as high-performing patient-centered medical homes. At the same time, we estimate that implementing the patient-centered medical home capabilities was associated with $155 million in lower medical costs in program year 2011 for Blue Cross Blue Shield of Michigan members. We intend to devote a higher percentage of reimbursement over time to communities of caregivers that offer high-value, system-based care, and a lower percentage of reimbursement to individual physicians on a service-specific basis.

Conceptual Design for a Dual-Bell Rocket Nozzle System Using a NASA F-15 Airplane as the Flight Testbed

NASA Technical Reports Server (NTRS)

Jones, Daniel S.; Ruf, Joseph H.; Bui, Trong T.; Martinez, Martel; St. John, Clinton W.

2014-01-01

The dual-bell rocket nozzle was first proposed in 1949, offering a potential improvement in rocket nozzle performance over the conventional-bell nozzle. Despite the performance advantages that have been predicted, both analytically and through static test data, the dual-bell nozzle has still not been adequately tested in a relevant flight environment. In 2013 a proposal was constructed that offered a NASA F-15 airplane as the flight testbed, with the plan to operate a dual-bell rocket nozzle during captive-carried flight. If implemented, this capability will permit nozzle operation into an external flow field similar to that of a launch vehicle, and facilitate an improved understanding of dual-bell nozzle plume sensitivity to external flow-field effects. More importantly, this flight testbed can be utilized to help quantify the performance benefit with the dual-bell nozzle, as well as to advance its technology readiness level. Toward this ultimate goal, this paper provides plans for future flights to quantify the external flow field of the airplane near the nozzle experiment, as well as details on the conceptual design for the dual-bell nozzle cold-flow propellant feed system integration within the NASA F-15 Propulsion Flight Test Fixture. The current study shows that this concept of flight research is feasible, and could result in valuable flight data for the dual-bell nozzle.

Comparing two types of navigational interfaces for Virtual Reality.

PubMed

Teixeira, Luís; Vilar, Elisângela; Duarte, Emília; Rebelo, Francisco; da Silva, Fernando Moreira

2012-01-01

Previous studies suggest significant differences between navigating virtual environments in a life-like walking manner (i.e., using treadmills or walk-in-place techniques) and virtual navigation (i.e., flying while really standing). The latter option, which usually involves hand-centric devices (e.g., joysticks), is the most common in Virtual Reality-based studies, mostly due to low costs, less space and technology demands. However, recently, new interaction devices, originally conceived for videogames have become available offering interesting potentialities for research. This study aimed to explore the potentialities of the Nintendo Wii Balance Board as a navigation interface in a Virtual Environment presented in an immersive Virtual Reality system. Comparing participants' performance while engaged in a simulated emergency egress allows determining the adequacy of such alternative navigation interface on the basis of empirical results. Forty university students participated in this study. Results show that participants were more efficient when performing navigation tasks using the Joystick than with the Balance Board. However there were no significantly differences in the behavioral compliance with exit signs. Therefore, this study suggests that, at least for tasks similar to the studied, the Balance Board have good potentiality to be used as a navigation interface for Virtual Reality systems.

48 CFR 13.106-2 - Evaluation of quotations or offers.

Code of Federal Regulations, 2011 CFR

2011-10-01

...; (C) The Governmentwide Past Performance Information Retrieval System (PPIRS) at www.ppirs.gov; or (D... quotations or offers, identify from all quotations or offers received one that is suitable to the user, such...

Empirical performance of the self-controlled case series design: lessons for developing a risk identification and analysis system.

PubMed

Suchard, Marc A; Zorych, Ivan; Simpson, Shawn E; Schuemie, Martijn J; Ryan, Patrick B; Madigan, David

2013-10-01

The self-controlled case series (SCCS) offers potential as an statistical method for risk identification involving medical products from large-scale observational healthcare data. However, analytic design choices remain in encoding the longitudinal health records into the SCCS framework and its risk identification performance across real-world databases is unknown. To evaluate the performance of SCCS and its design choices as a tool for risk identification in observational healthcare data. We examined the risk identification performance of SCCS across five design choices using 399 drug-health outcome pairs in five real observational databases (four administrative claims and one electronic health records). In these databases, the pairs involve 165 positive controls and 234 negative controls. We also consider several synthetic databases with known relative risks between drug-outcome pairs. We evaluate risk identification performance through estimating the area under the receiver-operator characteristics curve (AUC) and bias and coverage probability in the synthetic examples. The SCCS achieves strong predictive performance. Twelve of the twenty health outcome-database scenarios return AUCs >0.75 across all drugs. Including all adverse events instead of just the first per patient and applying a multivariate adjustment for concomitant drug use are the most important design choices. However, the SCCS as applied here returns relative risk point-estimates biased towards the null value of 1 with low coverage probability. The SCCS recently extended to apply a multivariate adjustment for concomitant drug use offers promise as a statistical tool for risk identification in large-scale observational healthcare databases. Poor estimator calibration dampens enthusiasm, but on-going work should correct this short-coming.

Environmental evaluation of the ULIS PICO1024 microbolometer

NASA Astrophysics Data System (ADS)

Dartois, Thierry; Manolis, Ilias; Bézy, Jean-Loup; Meynart, Roland; Tisse, Christel-Loïc.

2017-09-01

In recent years the European Space Agency (ESA) has been pursuing studies dedicated to Earth imaging from space in the Long Wave Infrared region for applications ranging from monitoring of evapotranspiration, and water resources management to the development of urban heat island and monitoring of high temperature events. Among the various solutions being studied is also that of a low cost instrument with moderate needs in terms of resources. . One potential enabler for such type of mission could be the technology of microbolometer detectors. The latest generation of microbolometer arrays now available offer large formats (XGA) and small pixel sizes which are favourable for keeping the instrument size within reasonable limit while addressing larger swath compared to VGA format. A major concern however, in using commercial microbolometers in space is their ability to sustain the radiation environment of space but also the harsh mechanical environments. COTS microbolometers are potentially susceptible to SEE (single even effects) because of the use of commercial CMOS technology/libraries and no implementation of specific design rules (i.e. space tailored rad hardened). In the past, and in the context of their national program, CNES has performed a space evaluation of COTS microbolometer arrays of 640x480 with 25 μm pitch[3]. Despite successful gamma irradiations and vibration tests; degradation of the ROIC has been evidenced during the heavy ions tests, which makes the full qualification of COTS microbolometers for future space programmes mandatory. Similar tests have been performed on an even earlier device (384x288 with a pitch of 35 μm) under the ESA EarthCARE programme[2]. ESA and Thales Alenia Space have recently run an activity with the objective to validate a third-generation COTS microbolometer offered by ULIS (France) against the relevant environment for a candidate Thermal InfraRed (TIR) space mission. The micro-bolometer selected is the PICO 1024E[1], which offers 1024x768 pixels of size 17 μm square. The validation sequence included the main types of irradiation tests required by a space application as well as vibration and shock tests. Ageing tests are included and synergetic effects are also investigated. The detector performances were tested before, after and during any test sequence. In this paper, the results of this activity achieved in the beginning of 2017 are reported.

The role of aesthetic experience in changing selves.

PubMed

Sinnett, E R

2000-02-01

Some rapprochement between psychology and the arts may have therapeutic potential as well as offer a basis for positive social interaction more generally. A simple proposal is offered as a foundation.

Advances in covalent organic frameworks in separation science.

PubMed

Qian, Hai-Long; Yang, Cheng-Xiong; Wang, Wen-Long; Yang, Cheng; Yan, Xiu-Ping

2018-03-23

Covalent organic frameworks (COFs) are a new class of multifunctional crystalline organic polymer constructed with organic monomers via robust covalent bonds. The unique properties such as convenient modification, low densities, large specific surface areas, good stability and permanent porosity make COFs great potential in separation science. This review shows the state-of-the art for the application of COFs and their composites in analytical separation science. COFs and their composites have been explored as promising sorbents for solid phase extraction, potential coatings for solid phase microextraction, and novel stationary phases for gas chromatography, high-performance liquid chromatography and capillary electrochromatography. The prospects of COFs for separation science are also presented, which can offer an outlook and reference for further study on the applications of COFs. Copyright © 2018 Elsevier B.V. All rights reserved.

Technology Projections for Solar Dynamic Power

NASA Technical Reports Server (NTRS)

Mason, Lee S.

1999-01-01

Solar Dynamic power systems can offer many potential benefits to Earth orbiting satellites including high solar-to-electric efficiency, long life without performance degradation, and high power capability. A recent integrated system test of a 2 kilowatt SD power system in a simulated space environment has successfully demonstrated technology readiness for space flight. Conceptual design studies of SD power systems have addressed several potential mission applications: a 10 kilowatt LEO satellite, a low power Space Based Radar, and a 30 kilowatt GEO communications satellite. The studies show that with moderate component development, SD systems can exhibit excellent mass and deployed area characteristics. Using the conceptual design studies as a basis, a SD technology roadmap was generated which identifies the component advances necessary to assure SD systems a competitive advantage for future NASA, DOD, and commercial missions.

Peroperative Gastrograffin bowel lavage in gastroschisis.

PubMed

Cherian, Abraham; Hallows, Ruth M; Singh, Shalinder J; McCallion, William A; Stewart, Richard J

2006-10-01

The aim of the study was to evaluate potential benefits in the use of peroperative bowel lavage with Gastrograffin in neonates with gastroschisis. A retrospective analysis of newborns with gastroschisis was performed over a 10-year period in 2 centers in the United Kingdom. Two groups were studied wherein one had peroperative bowel lavage with Gastrograffin and the other did not. Data were collected on 116 patients of whom 93 were suitable for analysis. There were no statistically significant differences in primary closure rate, duration of ventilation, parenteral nutrition, or hospital stay. Intestinal obstruction occurred more frequently in the nonlavage group. Gastrograffin lavage peroperatively in gastroschisis offers no potential advantage in reducing ventilatory requirements, parenteral nutrition, and hospital stay. It also does not achieve greater primary closure rates, but may reduce the incidence of intestinal obstruction.

Relaxation dynamics of C60

NASA Astrophysics Data System (ADS)

Walsh, Tiffany R.; Wales, David J.

1998-10-01

The relaxation dynamics of C60 from high-energy isomers to Buckminsterfullerene is examined using a master equation approach. An exhaustive catalog of the C60 fullerene isomers containing only five- and six-membered rings is combined with knowledge of the Stone-Wales rearrangements that connect all such isomers. Full geometry optimizations have been performed for all the minima and the transition states which connect them up to six Stone-Wales steps away from the global minimum. A density-functional tight-binding potential was employed to provide a quantum mechanical description of the bonding. The resulting picture of the potential energy landscape reveals a "weeping willow" structure which offers a clear explanation for the relatively long relaxation times observed experimentally. We also predict the most important transient local minima on the annealing pathway.

The performance of monotonic and new non-monotonic gradient ascent reconstruction algorithms for high-resolution neuroreceptor PET imaging.

PubMed

Angelis, G I; Reader, A J; Kotasidis, F A; Lionheart, W R; Matthews, J C

2011-07-07

Iterative expectation maximization (EM) techniques have been extensively used to solve maximum likelihood (ML) problems in positron emission tomography (PET) image reconstruction. Although EM methods offer a robust approach to solving ML problems, they usually suffer from slow convergence rates. The ordered subsets EM (OSEM) algorithm provides significant improvements in the convergence rate, but it can cycle between estimates converging towards the ML solution of each subset. In contrast, gradient-based methods, such as the recently proposed non-monotonic maximum likelihood (NMML) and the more established preconditioned conjugate gradient (PCG), offer a globally convergent, yet equally fast, alternative to OSEM. Reported results showed that NMML provides faster convergence compared to OSEM; however, it has never been compared to other fast gradient-based methods, like PCG. Therefore, in this work we evaluate the performance of two gradient-based methods (NMML and PCG) and investigate their potential as an alternative to the fast and widely used OSEM. All algorithms were evaluated using 2D simulations, as well as a single [(11)C]DASB clinical brain dataset. Results on simulated 2D data show that both PCG and NMML achieve orders of magnitude faster convergence to the ML solution compared to MLEM and exhibit comparable performance to OSEM. Equally fast performance is observed between OSEM and PCG for clinical 3D data, but NMML seems to perform poorly. However, with the addition of a preconditioner term to the gradient direction, the convergence behaviour of NMML can be substantially improved. Although PCG is a fast convergent algorithm, the use of a (bent) line search increases the complexity of the implementation, as well as the computational time involved per iteration. Contrary to previous reports, NMML offers no clear advantage over OSEM or PCG, for noisy PET data. Therefore, we conclude that there is little evidence to replace OSEM as the algorithm of choice for many applications, especially given that in practice convergence is often not desired for algorithms seeking ML estimates.

Review on α-Fe2O3 based negative electrode for high performance supercapacitors

NASA Astrophysics Data System (ADS)

Nithya, V. D.; Arul, N. Sabari

2016-09-01

Supercapacitor is an electrochemical energy storage device which has drawn attention of the researchers in recent years due to its high power density and long cycle life. Recently, an enormous effort has been imposed to improve the energy density of supercapacitor and might be attained through asymmetric cell configuration that offer wider potential window. Until now, a significant advancement has been achieved in the fabrication of positive electrodes for asymmetric cell. Nevertheless, the electrochemical performance of negative electrode materials is less explored, especially Hematite (α-Fe2O3). The α-Fe2O3 has been proved to be a promising negative electrode in supercapacitor application due to its wide operating potential, high redox activity, low cost, abundant availability and eco-friendliness. In this review, we have chosen α-Fe2O3 as the negative electrode and discussed its latest research progress with emphasis on various surface engineering synthesis strategies such as, carbon, polymer, metal-metal oxide, and ternary based α-Fe2O3 composites for supercapacitor. Besides, the importance of their synergistic effects over the supercapacitive performance in terms of specific capacitance, energy density, power density, cycling life and rate capability are highlighted. Also, an extensive analysis of the literature about its symmetric/asymmetric cell performance is explored.

Investigation of Methods for Selectively Reinforcing Aluminum and Aluminum-Lithium Materials

NASA Technical Reports Server (NTRS)

Bird, R. Keith; Alexa, Joel A.; Messick, Peter L.; Domack, Marcia S.; Wagner, John A.

2013-01-01

Several studies have indicated that selective reinforcement offers the potential to significantly improve the performance of metallic structures for aerospace applications. Applying high-strength, high-stiffness fibers to the high-stress regions of aluminum-based structures can increase the structural load-carrying capability and inhibit fatigue crack initiation and growth. This paper discusses an investigation into potential methods for applying reinforcing fibers onto the surface of aluminum and aluminum-lithium plate. Commercially-available alumina-fiber reinforced aluminum alloy tapes were used as the reinforcing material. Vacuum hot pressing was used to bond the reinforcing tape to aluminum alloy 2219 and aluminum-lithium alloy 2195 base plates. Static and cyclic three-point bend testing and metallurgical analysis were used to evaluate the enhancement of mechanical performance and the integrity of the bond between the tape and the base plate. The tests demonstrated an increase in specific bending stiffness. In addition, no issues with debonding of the reinforcing tape from the base plate during bend testing were observed. The increase in specific stiffness indicates that selectively-reinforced structures could be designed with the same performance capabilities as a conventional unreinforced structure but with lower mass.

No evidence that 'fast-mapping' benefits novel learning in healthy Older adults.

PubMed

Greve, Andrea; Cooper, Elisa; Henson, Richard N

2014-07-01

Much evidence suggests that the Hippocampus is necessary for learning novel associations. Contrary to this, Sharon, Moscovitch, and Gilboa (2011) reported four amnesic patients with Hippocampal damage who maintained the capacity to learn novel object-name associations when trained with a 'fast-mapping' (FM) technique. This technique therefore potentially offers an alternative route for learning novel information in populations experiencing memory problems. We examined this potential in healthy ageing, by comparing 24 Older and 24 Young participants who completed a FM procedure very similar to Sharon et al. (2011). As expected, the Older group showed worse memory than the Young group under standard explicit encoding (EE) instructions. However, the Older group continued to show worse performance under the FM procedure, with no evidence that FM alleviated their memory deficit. Indeed, performance was worse for the FM than EE condition in both groups. Structural MRI scans confirmed reduced Hippocampal grey-matter volume in the Older group, which correlated with memory performance across both groups and both EE/FM conditions. We conclude FM does not help memory problems that occur with normal ageing, and discuss theoretical implications for memory theories. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Tools to Use in an Information Technology Class--and Best of All They Are FREE!

ERIC Educational Resources Information Center

Swanson, Dewey; Gusev, Dmitri A.

2016-01-01

Purdue Polytechnic has several locations in the state of Indiana offering students a chance to get a Purdue degree. The Computer and Information Technology (CIT) department offers the CIT degree at three sites in Indiana: Anderson, Columbus and Kokomo. CIT offers several potential majors including Cybersecurity, Network Engineering, Systems…

Static Performance of Six Innovative Thrust Reverser Concepts for Subsonic Transport Applications: Summary of the NASA Langley Innovative Thrust Reverser Test Program

NASA Technical Reports Server (NTRS)

Asbury, Scott C.; Yetter, Jeffrey A.

2000-01-01

The NASA Langley Configuration Aerodynamics Branch has conducted an experimental investigation to study the static performance of innovative thrust reverser concepts applicable to high-bypass-ratio turbofan engines. Testing was conducted on a conventional separate-flow exhaust system configuration, a conventional cascade thrust reverser configuration, and six innovative thrust reverser configurations. The innovative thrust reverser configurations consisted of a cascade thrust reverser with porous fan-duct blocker, a blockerless thrust reverser, two core-mounted target thrust reversers, a multi-door crocodile thrust reverser, and a wing-mounted thrust reverser. Each of the innovative thrust reverser concepts offer potential weight savings and/or design simplifications over a conventional cascade thrust reverser design. Testing was conducted in the Jet-Exit Test Facility at NASA Langley Research Center using a 7.9%-scale exhaust system model with a fan-to-core bypass ratio of approximately 9.0. All tests were conducted with no external flow and cold, high-pressure air was used to simulate core and fan exhaust flows. Results show that the innovative thrust reverser concepts achieved thrust reverser performance levels which, when taking into account the potential for system simplification and reduced weight, may make them competitive with, or potentially more cost effective than current state-of-the-art thrust reverser systems.

Performance of broiler chickens given whey in the food and/or drinking water.

PubMed

Shariatmadari, F; Forbes, J M

2005-08-01

1. The effects on food intake and weight gain of offering broiler chickens (2 to 7 weeks of age) dry food, wet food, wet food containing whey, whey as drinking liquid and combinations of two of these were studied in 5 experiments. 2. Wet feed generally improved both weight gain and feed efficiencies significantly. Feeding whey also improved weight gain and feed conversion efficiency, but whey offered as a drinking fluid had an adverse effect on broiler performance. 3. When whey was offered both as drinking liquid and added to the food it had a deleterious effect. 4. When whey was offered from 4 or 6 weeks of age, it had a better effect than when offered from 2 weeks of age. 5. There was better performance when whey in the drinking water was diluted and/or offered on alternate days or half-days. 6. Broilers allowed to choose between wet and dry feed when water was freely available chose mostly dry feed; in the absence of drinking water they chose mostly wet food. Birds offered water and liquid whey avoided whey completely. 7. It is concluded that whey can be used in diets for broiler chickens by incorporating it in the food as long as drinking water is offered ad libitum. Whey may be offered as a drink if the food is mixed with 1.8 times its weight of water but it is better to dilute the whey with an equal volume of water whether it is added to food or given as drink. Good results can also be obtained when undiluted whey is offered alternately with water, either in half-day or full-day periods.

Nanoionics-Based Switches for Radio-Frequency Applications

NASA Technical Reports Server (NTRS)

Nessel, James; Lee, Richard

2010-01-01

Nanoionics-based devices have shown promise as alternatives to microelectromechanical systems (MEMS) and semiconductor diode devices for switching radio-frequency (RF) signals in diverse systems. Examples of systems that utilize RF switches include phase shifters for electronically steerable phased-array antennas, multiplexers, cellular telephones and other radio transceivers, and other portable electronic devices. Semiconductor diode switches can operate at low potentials (about 1 to 3 V) and high speeds (switching times of the order of nanoseconds) but are characterized by significant insertion loss, high DC power consumption, low isolation, and generation of third-order harmonics and intermodulation distortion (IMD). MEMS-based switches feature low insertion loss (of the order of 0.2 dB), low DC power consumption (picowatts), high isolation (>30 dB), and low IMD, but contain moving parts, are not highly reliable, and must be operated at high actuation potentials (20 to 60 V) generated and applied by use of complex circuitry. In addition, fabrication of MEMS is complex, involving many processing steps. Nanoionics-based switches offer the superior RF performance and low power consumption of MEMS switches, without need for the high potentials and complex circuitry necessary for operation of MEMS switches. At the same time, nanoionics-based switches offer the high switching speed of semiconductor devices. Also, like semiconductor devices, nanoionics-based switches can be fabricated relatively inexpensively by use of conventional integrated-circuit fabrication techniques. More over, nanoionics-based switches have simple planar structures that can easily be integrated into RF power-distribution circuits.

Effect of whole-crop pea (Pisum sativum L.) silages differing in condensed tannin content as a substitute for grass silage and soybean meal on the performance, metabolism, and carcass characteristics of lambs.

PubMed

Hart, K J; Sinclair, L A; Wilkinson, R G; Huntington, J A

2011-11-01

Two experiments were conducted to investigate the effect of inclusion of whole-crop pea (WCP) silages, differing in condensed tannin content, as a substitute for grass silage (GS) and soybean meal on lamb metabolism, performance, plasma metabolites, digestibility, and carcass characteristics. In both experiments lambs were offered either solely GS or a 50:50 mix on a DM basis of GS with either low-tannin (LTPS) or high-tannin (HTPS) pea silage ad libitum. Each forage mix was fed with either 400 g/d of low-protein (LP) concentrate or 400 g/d of LP with an additional 200 g/d of pelletized soybean meal (HP), resulting in 6 dietary treatments. Experiment 1 examined the effects of the diets on metabolism, digestibility, and N balance using 6 lambs in 4 periods of 21 d in an incomplete crossover design. Experiment 2 used 48 lambs and examined the effects of the diets on ADG, plasma metabolites, and carcass characteristics over 56 d. Both experiments were analyzed using a 3 × 2 factorial arrangement of treatments. In Exp. 1, lambs offered the LTPS diets had a greater (P < 0.05) digestibility of DM and OM than those offered the GS diets. Lambs offered the WCP silages had an increased (P < 0.05) N intake, N output, and digestibility of GE compared with those offered GS. Mean N digestibility was greatest (P < 0.05) in lambs offered LTPS. Lambs offered HP diets had increased (P < 0.001) digestibility of DM, OM, GE and N, and N- intake, output, retention, and digestibility compared with those offered the LP diets. In Exp. 2, there was no effect (P > 0.05) of forage type on intake, slaughter BW, or feed conversion efficiency (FCE). However, lambs offered the LTPS had a greater (P < 0.05) ADG than those offered the GS diets. Feeding diets containing HP increased (P < 0.001) total DMI, slaughter BW, ADG, and FCE. Lambs offered the WCP had a greater (P < 0.05) plasma β-hydroxybutyrate and urea concentration compared with those offered the GS diets. Feeding lambs HP diets increased (P < 0.05) plasma urea and total protein. Forage mix had no effect (P > 0.05) on carcass composition except for fat depth, which was greater (P < 0.05) in lambs offered WCP silage. Diets containing the HP increased (P < 0.05) carcass weight, hind leg circumference, chop dimensions, and kidney weight. It was concluded that lambs offered LTPS performed better than those offered GS and that LTPS has a concentrate sparing effect. Additionally, the increased tannin concentration in HTPS did not increase performance over lambs offered either GS or LTPS.

Performance and Characterization of a Modular Superconducting Nanowire Single Photon Detector System for Space-to-Earth Optical Communications Links

NASA Technical Reports Server (NTRS)

Vyhnalek, Brian E.; Tedder, Sarah A.; Nappier, Jennifer M.

2018-01-01

Space-to-ground photon-counting optical communication links supporting high data rates over large distances require enhanced ground receiver sensitivity in order to reduce the mass and power burden on the spacecraft transmitter. Superconducting nanowire single-photon detectors (SNSPDs) have been demonstrated to offer superior performance in detection efficiency, timing resolution, and count rates over semiconductor photodetectors, and are a suitable technology for high photon efficiency links. Recently photon detectors based on superconducting nanowires have become commercially available, and we have assessed the characteristics and performance of one such commercial system as a candidate for potential utilization in ground receiver designs. The SNSPD system features independent channels which can be added modularly, and we analyze the scalability of the system to support different data rates, as well as consider coupling concepts and issues as the number of channels increases.

Explosive Welding in the 1990's

NASA Technical Reports Server (NTRS)

Lalwaney, N. S.; Linse, V. D.

1985-01-01

Explosive bonding is a unique joining process with the serious potential to produce composite materials capable of fulfilling many of the high performance materials capable of fulfilling many of the high performance materials needs of the 1990's. The process has the technological versatility to provide a true high quality metallurgical compatible and incompatible systems. Metals routinely explosively bonded include a wide variety of combinations of reactive and refractory metals, low and high density metals and their alloys, corrosion resistant and high strength alloys, and common steels. The major advantage of the process is its ability to custom design and engineer composites with physical and/or mechanical properties that meet a specific or unusual performance requirement. Explosive bonding offers the designer unique opportunities in materials selection with unique combinations of properties and high integrity bonds that cannot be achieved by any other metal joining process. The process and some applications are discussed.

Improved uniformity in high-performance organic photovoltaics enabled by (3-aminopropyl)triethoxysilane cathode functionalization.

PubMed

Luck, Kyle A; Shastry, Tejas A; Loser, Stephen; Ogien, Gabriel; Marks, Tobin J; Hersam, Mark C

2013-12-28

Organic photovoltaics have the potential to serve as lightweight, low-cost, mechanically flexible solar cells. However, losses in efficiency as laboratory cells are scaled up to the module level have to date impeded large scale deployment. Here, we report that a 3-aminopropyltriethoxysilane (APTES) cathode interfacial treatment significantly enhances performance reproducibility in inverted high-efficiency PTB7:PC71BM organic photovoltaic cells, as demonstrated by the fabrication of 100 APTES-treated devices versus 100 untreated controls. The APTES-treated devices achieve a power conversion efficiency of 8.08 ± 0.12% with histogram skewness of -0.291, whereas the untreated controls achieve 7.80 ± 0.26% with histogram skewness of -1.86. By substantially suppressing the interfacial origins of underperforming cells, the APTES treatment offers a pathway for fabricating large-area modules with high spatial performance uniformity.

[Management practices in medium-sized private hospitals in São Paulo, Brazil].

PubMed

Brito, Luiz Artur Ledur; Malik, Ana Maria; Brito, Eliane; Bulgacov, Sergio; Andreassi, Tales

2017-04-03

Traditional management practices are sometimes considered merely a necessary condition for superior performance. Other resources and competencies with higher barriers to imitation are assumed to be potential sources of competitive advantage. This study describes and analyzes the effect of traditional management practices on the performance of medium-sized hospitals. Medium-sized companies frequently display the greatest differences in management practices, and only recently did the hospital sector seek ways to develop its competitiveness in the administrative arena. The results generally indicate that basic management practices can make differences in performance, offering support for the new practice-based view (PBV). Hospitals with the highest rate of adoption of practices had the highest occupancy rate, hospital-bed admissions, and accreditation. Lack of adoption of management practices by medium-sized hospitals limits their competitive capacity and can be viewed as a component of the so-called Brazil cost, but in this case an internal component.

Ka-Band Phased Array System Characterization

NASA Technical Reports Server (NTRS)

Acosta, R.; Johnson, S.; Sands, O.; Lambert, K.

2001-01-01

Phased Array Antennas (PAAs) using patch-radiating elements are projected to transmit data at rates several orders of magnitude higher than currently offered with reflector-based systems. However, there are a number of potential sources of degradation in the Bit Error Rate (BER) performance of the communications link that are unique to PAA-based links. Short spacing of radiating elements can induce mutual coupling between radiating elements, long spacing can induce grating lobes, modulo 2 pi phase errors can add to Inter Symbol Interference (ISI), phase shifters and power divider network introduce losses into the system. This paper describes efforts underway to test and evaluate the effects of the performance degrading features of phased-array antennas when used in a high data rate modulation link. The tests and evaluations described here uncover the interaction between the electrical characteristics of a PAA and the BER performance of a communication link.

Understanding and removing surface states limiting charge transport in TiO2 nanowire arrays for enhanced optoelectronic device performance.

PubMed

Sheng, Xia; Chen, Liping; Xu, Tao; Zhu, Kai; Feng, Xinjian

2016-03-01

Charge transport within electrode materials plays a key role in determining the optoelectronic device performance. Aligned single-crystal TiO 2 nanowire arrays offer an ideal electron transport path and are expected to have higher electron mobility. Unfortunately, their transport is found not to be superior to that in nanoparticle films. Here we show that the low electron transport in rutile TiO 2 nanowires is mainly caused by surface traps in relatively deep energy levels, which cannot be removed by conventional approaches, such as oxygen annealing treatment. Moreover, we demonstrate an effective wet-chemistry approach to minimize these trap states, leading to over 20-fold enhancement in electron diffusion coefficient and 62% improvement in solar cell performance. On the basis of our results, the potential of TiO 2 NWs can be developed and well-utilized, which is significantly important for their practical applications.

Chronic Conditions, Workplace Safety, And Job Demands Contribute To Absenteeism And Job Performance.

PubMed

Jinnett, Kimberly; Schwatka, Natalie; Tenney, Liliana; Brockbank, Claire V S; Newman, Lee S

2017-02-01

An aging workforce, increased prevalence of chronic health conditions, and the potential for longer working lives have both societal and economic implications. We analyzed the combined impact of workplace safety, employee health, and job demands (work task difficulty) on worker absence and job performance. The study sample consisted of 16,926 employees who participated in a worksite wellness program offered by a workers' compensation insurer to their employers-314 large, midsize, and small businesses in Colorado across multiple industries. We found that both workplace safety and employees' chronic health conditions contributed to absenteeism and job performance, but their impact was influenced by the physical and cognitive difficulty of the job. If employers want to reduce health-related productivity losses, they should take an integrated approach to mitigate job-related injuries, promote employee health, and improve the fit between a worker's duties and abilities. Project HOPE—The People-to-People Health Foundation, Inc.

A novel approach for evaluating the performance of real time quantitative loop-mediated isothermal amplification-based methods.

PubMed

Nixon, Gavin J; Svenstrup, Helle F; Donald, Carol E; Carder, Caroline; Stephenson, Judith M; Morris-Jones, Stephen; Huggett, Jim F; Foy, Carole A

2014-12-01

Molecular diagnostic measurements are currently underpinned by the polymerase chain reaction (PCR). There are also a number of alternative nucleic acid amplification technologies, which unlike PCR, work at a single temperature. These 'isothermal' methods, reportedly offer potential advantages over PCR such as simplicity, speed and resistance to inhibitors and could also be used for quantitative molecular analysis. However there are currently limited mechanisms to evaluate their quantitative performance, which would assist assay development and study comparisons. This study uses a sexually transmitted infection diagnostic model in combination with an adapted metric termed isothermal doubling time (IDT), akin to PCR efficiency, to compare quantitative PCR and quantitative loop-mediated isothermal amplification (qLAMP) assays, and to quantify the impact of matrix interference. The performance metric described here facilitates the comparison of qLAMP assays that could assist assay development and validation activities.

Information-based approach to performance estimation and requirements allocation in multisensor fusion for target recognition

NASA Astrophysics Data System (ADS)

Harney, Robert C.

1997-03-01

A novel methodology offering the potential for resolving two of the significant problems of implementing multisensor target recognition systems, i.e., the rational selection of a specific sensor suite and optimal allocation of requirements among sensors, is presented. Based on a sequence of conjectures (and their supporting arguments) concerning the relationship of extractable information content to recognition performance of a sensor system, a set of heuristics (essentially a reformulation of Johnson's criteria applicable to all sensor and data types) is developed. An approach to quantifying the information content of sensor data is described. Coupling this approach with the widely accepted Johnson's criteria for target recognition capabilities results in a quantitative method for comparing the target recognition ability of diverse sensors (imagers, nonimagers, active, passive, electromagnetic, acoustic, etc.). Extension to describing the performance of multiple sensors is straightforward. The application of the technique to sensor selection and requirements allocation is discussed.

Reconfigurable Complementary Logic Circuits with Ambipolar Organic Transistors

PubMed Central

Yoo, Hocheon; Ghittorelli, Matteo; Smits, Edsger C. P.; Gelinck, Gerwin H.; Lee, Han-Koo; Torricelli, Fabrizio; Kim, Jae-Joon

2016-01-01

Ambipolar organic electronics offer great potential for simple and low-cost fabrication of complementary logic circuits on large-area and mechanically flexible substrates. Ambipolar transistors are ideal candidates for the simple and low-cost development of complementary logic circuits since they can operate as n-type and p-type transistors. Nevertheless, the experimental demonstration of ambipolar organic complementary circuits is limited to inverters. The control of the transistor polarity is crucial for proper circuit operation. Novel gating techniques enable to control the transistor polarity but result in dramatically reduced performances. Here we show high-performance non-planar ambipolar organic transistors with electrical control of the polarity and orders of magnitude higher performances with respect to state-of-art split-gate ambipolar transistors. Electrically reconfigurable complementary logic gates based on ambipolar organic transistors are experimentally demonstrated, thus opening up new opportunities for ambipolar organic complementary electronics. PMID:27762321

Reconfigurable Complementary Logic Circuits with Ambipolar Organic Transistors.

PubMed

Yoo, Hocheon; Ghittorelli, Matteo; Smits, Edsger C P; Gelinck, Gerwin H; Lee, Han-Koo; Torricelli, Fabrizio; Kim, Jae-Joon

2016-10-20

Ambipolar organic electronics offer great potential for simple and low-cost fabrication of complementary logic circuits on large-area and mechanically flexible substrates. Ambipolar transistors are ideal candidates for the simple and low-cost development of complementary logic circuits since they can operate as n-type and p-type transistors. Nevertheless, the experimental demonstration of ambipolar organic complementary circuits is limited to inverters. The control of the transistor polarity is crucial for proper circuit operation. Novel gating techniques enable to control the transistor polarity but result in dramatically reduced performances. Here we show high-performance non-planar ambipolar organic transistors with electrical control of the polarity and orders of magnitude higher performances with respect to state-of-art split-gate ambipolar transistors. Electrically reconfigurable complementary logic gates based on ambipolar organic transistors are experimentally demonstrated, thus opening up new opportunities for ambipolar organic complementary electronics.

Brush Seals for Improved Steam Turbine Performance

NASA Technical Reports Server (NTRS)

Turnquist, Norman; Chupp, Ray; Baily, Fred; Burnett, Mark; Rivas, Flor; Bowsher, Aaron; Crudgington, Peter

2006-01-01

GE Energy has retrofitted brush seals into more than 19 operating steam turbines. Brush seals offer superior leakage control compared to labyrinth seals, owing to their compliant nature and ability to maintain very tight clearances to the rotating shaft. Seal designs have been established for steam turbines ranging in size from 12 MW to over 1200 MW, including fossil, nuclear, combined-cycle and industrial applications. Steam turbines present unique design challenges that must be addressed to ensure that the potential performance benefits of brush seals are realized. Brush seals can have important effects on the overall turbine system that must be taken into account to assure reliable operation. Subscale rig tests are instrumental to understanding seal behavior under simulated steam-turbine operating conditions, prior to installing brush seals in the field. This presentation discusses the technical challenges of designing brush seals for steam turbines; subscale testing; performance benefits of brush seals; overall system effects; and field applications.

Accepting multiple simultaneous liver offers does not negatively impact transplant outcomes.

PubMed

Eldeen, Firas Zahr; Mourad, Moustafa Mabrouk; Bhandari, Mayank; Roll, Garrett; Gunson, Bridget; Mergental, Hynek; Bramhall, Simon; Isaac, John; Muiesan, Paolo; Mirza, Darius F; Perera, M Thamara P R

2016-02-01

Impact of performing multiple liver transplants (LT) in a short period of time is unknown. Consecutively performed LT potentially increase complication rates through team fatigue and overutilization of resources and increase ischemia time. We analyzed the impact of undertaking consecutive LT (Consecutive liver transplant, CLT; LT preceded by another transplant performed not more than 12 h before, both transplants grouped together) on outcomes. Of 1702 LT performed, 314 (18.4%) were CLT. Outcome data was compared with solitary LT (SLT; not more than one LT in 12-h period). Recipient, donor, and graft characteristics were evenly matched between SLT and CLT; second LT of CLT group utilized younger donors grafts with longer cold ischemic times (P = 0.015). Implantation and operative time were significantly lower in CLT recipients on intergroup analysis (P = 0.0001 and 0.002, respectively). Early hepatic artery thrombosis (E-HAT) was higher in CLT versus SLT (P = 0.038), despite absolute number of E-HAT being low in all groups. Intragroup analysis demonstrated a trend toward more frequent E-HAT in first LT, compared to subsequent transplants; however, difference did not reach statistical significance (P = 0.135). In era of organ scarcity, CLT performed at high-volume center is safe and allows pragmatic utilization of organs, potentially reducing number of discarded grafts and reducing waiting list mortality. © 2015 Steunstichting ESOT.

Comparison of Portable and Bench-Top Spectrometers for Mid-Infrared Diffuse Reflectance Measurements of Soils.

PubMed

Hutengs, Christopher; Ludwig, Bernard; Jung, András; Eisele, Andreas; Vohland, Michael

2018-03-27

Mid-infrared (MIR) spectroscopy has received widespread interest as a method to complement traditional soil analysis. Recently available portable MIR spectrometers additionally offer potential for on-site applications, given sufficient spectral data quality. We therefore tested the performance of the Agilent 4300 Handheld FTIR (DRIFT spectra) in comparison to a Bruker Tensor 27 bench-top instrument in terms of (i) spectral quality and measurement noise quantified by wavelet analysis; (ii) accuracy of partial least squares (PLS) calibrations for soil organic carbon (SOC), total nitrogen (N), pH, clay and sand content with a repeated cross-validation analysis; and (iii) key spectral regions for these soil properties identified with a Monte Carlo spectral variable selection approach. Measurements and multivariate calibrations with the handheld device were as good as or slightly better than Bruker equipped with a DRIFT accessory, but not as accurate as with directional hemispherical reflectance (DHR) data collected with an integrating sphere. Variations in noise did not markedly affect the accuracy of multivariate PLS calibrations. Identified key spectral regions for PLS calibrations provided a good match between Agilent and Bruker DHR data, especially for SOC and N. Our findings suggest that portable FTIR instruments are a viable alternative for MIR measurements in the laboratory and offer great potential for on-site applications.

A soft gamma-ray concentrator using thin-film multilayer structures

NASA Astrophysics Data System (ADS)

Bloser, Peter F.; Aliotta, Paul H.; Echt, Olof; Krzanowski, James E.; Legere, Jason S.; McConnell, Mark L.; Shirazi, Farzane; Tsavalas, John G.; Wong, Emily N.; Kippen, R. Marc

2015-09-01

We have begun to investigate the use of thin-film, multilayer structures to form optics capable of concentrating soft gamma rays with energies greater than 100 keV, beyond the reach of current grazing-incidence hard X-ray mirrors. Alternating layers of low- and high-density materials (e.g., polymers and metals) will channel soft gamma-ray photons via total external reflection. A suitable arrangement of bent structures will then concentrate the incident radiation to a point. Gamma-ray optics made in this way offer the potential for soft gamma-ray telescopes with focal lengths of less than 10 m, removing the need for formation flying spacecraft and opening the field up to balloon-borne instruments. Building on initial investigations at Los Alamos National Laboratory, we are investigating whether it is possible to grow such flexible multi-layer structures with the required thicknesses and smoothness using magnetron sputter and pulsed laser deposition techniques. We present the initial results of tests aimed at fabricating such structures by combining magnetron sputtering with either spin coating or pulsed laser deposition, and demonstrating gamma-ray channeling of 122 keV photons in the laboratory. If successful, this technology offers the potential for transformational increases in sensitivity while dramatically improving the system-level performance of future high-energy astronomy missions through reduced mass and complexity.

A study into the effectiveness of unqualified GP assistants.

PubMed

Philip, Marilyn; Turnbull, Betty

This article aims to address the potential shortfall in care provision offered by general practitioners (GPs) resulting from pending retirement and the retention and recruitment crisis. An educational module was developed that offered both theory and practise to unqualified general practice assistants. The module content was determined following discussion with local GPs. A small qualitative study of six students was carried out to review efficacy of participants in their new role. Using a grounded theory approach, participant and supervisor views of course content and delivery, role preparation diversity were analysed and compared. Tape-recorded interviews were conducted and analysis carried out employing the constant comparative method. Data were coded and emergent themes categorized. Overall, participants agreed that the module had strengthened their knowledge, added new skills, heightened their job satisfaction, added significant diversity to their role and enhanced their employability potential. Five participants communicated that they were more confident in performing clinical skills and advising health improvement techniques. Supervisors also reported that participants displayed a more competent and professional approach to health care, which was complementary to the role of the GP and practice nurse. Ultimately this allowed both GP and practice nurse to focus on dealing with chronic illness targets, as required in the new directive (Scottish Executive, 2004).

Counterfactual comparison modulates fairness consideration in the mini-ultimatum game: an event-related potentials study.

PubMed

Liang, Jiafeng; Lin, Huiyan; Xiang, Jing; Wu, Hao; Li, Xu; Liang, Hongyu; Zheng, Xue

2015-04-01

Existing literature on the mini-ultimatum game indicates that counterfactual comparison between chosen and unchosen alternatives is of great importance for individual's fairness consideration. However, it is still unclear how counterfactual comparison influences the electrophysiological responses to unfair chosen offers. In conjunction with event-related potentials' (ERPs) technique, the current study aimed to explore the issue by employing a modified version of the mini-ultimatum game where a fixed set of two alternatives (unfair offer vs. fair alternative, unfair vs. hyperfair alternative, unfair offer vs. hyperunfair alternative) was presented before the chosen offer. The behavioral results showed that participants were more likely to accept unfair chosen offers when the unchosen alternative was hyperunfair than when the unchosen alternative was fair or hyperfair. The ERPs results showed that the feedback-related negativity (FRN) elicited by unfair chosen offers was insensitive to the type of unchosen alternative when correcting for possible overlap with other components. In contrast, unfair chosen offers elicited larger P300 amplitudes when the unchosen alternative was hyperunfair than when the unchosen alternative was fair or hyperfair. These findings suggest that counterfactual comparison may take effect at later stages of fairness consideration as reflected by the P300. © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

Mitigation of hard x-ray background in backlit pinhole imagers

DOE PAGES

Fein, J. R.; Keiter, P. A.; Holloway, J. P.; ...

2016-09-16

Experiments were performed to mitigate the hard x-ray background commonly observed in backlit pinhole imagers. The material of the scaffold holding the primary backlighter foil was varied to reduce the laser-plasma instabilities responsible for hot electrons and resulting hard x-ray background. Radiographic measurements with image plates showed a factor of >25 decrease in x-rays between 30 and 67 keV when going from a plastic to Al or V scaffold. Here, a potential design using V scaffold offers a signal-to-background ratio of 6:1, a factor of 2 greater than using the bare plastic scaffold.

Sol-Gel Processing of MgF2 Antireflective Coatings

PubMed Central

Löbmann, Peer

2018-01-01

There are different approaches for the preparation of porous antireflective λ/4 MgF2 films from liquid precursors. Among these, the non-aqueous fluorolytic synthesis of precursor solutions offers many advantages in terms of processing simplicity and scalability. In this paper, the structural features and optical performance of the resulting films are highlighted, and their specific interactions with different inorganic substrates are discussed. Due to their excellent abrasion resistance, coatings have a high potential for applications on glass. Using solvothermal treatment of precursor solutions, also the processing of thermally sensitive polymer substrates becomes feasible. PMID:29724064

Calculations of transonic boattail flow at small angle of attack

NASA Technical Reports Server (NTRS)

Nakayama, A.; Chow, W. L.

1979-01-01

A transonic flow past a boattailed afterbody under a small angle of attack was examined. It is known that the viscous effect offers significant modifications of the pressure distribution on the afterbody. Thus, the formulation for the inviscid flow was based on the consideration of a flow past a nonaxisymmetric body. The full three dimensional potential equation was solved through numerical relaxation, and quasi-axisymmetric boundary layer calculations were performed to estimate the displacement effect. It was observed again that the viscous effects were not negligible. The trend of the final results agreed well with the experimental data.

Aerocrane: A hybrid LTA aircraft for aerial crane applications

NASA Technical Reports Server (NTRS)

Perkins, R. G., Jr.; Doolittle, D. B.

1975-01-01

The Aerocrane, a hybrid aircraft, combines rotor lift with buoyant lift to offer VTOL load capability greatly in excess of helicopter technology while eliminating the airship problem of ballast transfer. In addition, the Aerocrane concept sharply reduces the mooring problem of airships and provides 360 deg vectorable thrust to supply a relatively large force component for control of gust loads. Designed for use in short range, ultra heavy lift missions, the Aerocrane operates in a performance envelope unsuitable for either helicopters or airships. Basic design considerations and potential problem areas of the concept are addressed.

AGAMA: Action-based galaxy modeling framework

NASA Astrophysics Data System (ADS)

Vasiliev, Eugene

2018-05-01

The AGAMA library models galaxies. It computes gravitational potential and forces, performs orbit integration and analysis, and can convert between position/velocity and action/angle coordinates. It offers a framework for finding best-fit parameters of a model from data and self-consistent multi-component galaxy models, and contains useful auxiliary utilities such as various mathematical routines. The core of the library is written in C++, and there are Python and Fortran interfaces. AGAMA may be used as a plugin for the stellar-dynamical software packages galpy (ascl:1411.008), AMUSE (ascl:1107.007), and NEMO (ascl:1010.051).

Modular disposable can (MODCAN) crash cushion: A concept investigation

NASA Technical Reports Server (NTRS)

Knoell, A.; Wilson, A.

1976-01-01

A conceptual design investigation of an improved highway crash cushion system is presented. The system is referred to as a modular disposable can (MODCAN) crash system. It is composed of a modular arrangement of disposable metal beverage cans configured to serve as an effective highway impact attenuation system. Experimental data, design considerations, and engineering calculations supporting the design development are presented. Design performance is compared to that of a conventional steel drum system. It is shown that the MODCAN concepts offers the potential for smoother and safer occupant deceleration for a larger class of vehicle impact weights than the steel drum device.

Thoracoscopic versus robotic approaches: advantages and disadvantages.

PubMed

Wei, Benjamin; D'Amico, Thomas A

2014-05-01

The overall advantages of thoracoscopy over thoracotomy in terms of patient recovery have been fairly well established. The use of robotics, however, is a newer and less proven modality in the realm of thoracic surgery. Robotics offers distinct advantages and disadvantages in comparison with video-assisted thoracoscopic surgery. Robotic technology is now used for a variety of complex cardiac, urologic, and gynecologic procedures including mitral valve repair and microsurgical treatment of male infertility. This article addresses the potential benefits and limitations of using the robotic platform for the performance of a variety of thoracic operations. Copyright © 2014 Elsevier Inc. All rights reserved.

Neutron and X-ray Tomography (NeXT) system for simultaneous, dual modality tomography.

PubMed

LaManna, J M; Hussey, D S; Baltic, E; Jacobson, D L

2017-11-01

Dual mode tomography using neutrons and X-rays offers the potential of improved estimation of the composition of a sample from the complementary interaction of the two probes with the sample. We have developed a simultaneous neutron and 90 keV X-ray tomography system that is well suited to the study of porous media systems such as fuel cells, concrete, unconventional reservoir geologies, limestones, and other geological media. We present the characteristic performance of both the neutron and X-ray modalities. We illustrate the use of the simultaneous acquisition through improved phase identification in a concrete core.

Neutron and X-ray Tomography (NeXT) system for simultaneous, dual modality tomography

NASA Astrophysics Data System (ADS)

LaManna, J. M.; Hussey, D. S.; Baltic, E.; Jacobson, D. L.

2017-11-01

Dual mode tomography using neutrons and X-rays offers the potential of improved estimation of the composition of a sample from the complementary interaction of the two probes with the sample. We have developed a simultaneous neutron and 90 keV X-ray tomography system that is well suited to the study of porous media systems such as fuel cells, concrete, unconventional reservoir geologies, limestones, and other geological media. We present the characteristic performance of both the neutron and X-ray modalities. We illustrate the use of the simultaneous acquisition through improved phase identification in a concrete core.

Parallel solution of sparse one-dimensional dynamic programming problems

NASA Technical Reports Server (NTRS)

Nicol, David M.

1989-01-01

Parallel computation offers the potential for quickly solving large computational problems. However, it is often a non-trivial task to effectively use parallel computers. Solution methods must sometimes be reformulated to exploit parallelism; the reformulations are often more complex than their slower serial counterparts. We illustrate these points by studying the parallelization of sparse one-dimensional dynamic programming problems, those which do not obviously admit substantial parallelization. We propose a new method for parallelizing such problems, develop analytic models which help us to identify problems which parallelize well, and compare the performance of our algorithm with existing algorithms on a multiprocessor.

Surgery for gastrinoma.

PubMed

Cisco, Robin M; Norton, Jeffrey A

2007-01-01

Surgery has been demonstrated to offer potential for cure in patients who have sporadic ZES and improved tumor-related survival in all patients who have ZES with gastrinomas larger than 2.5 cm. Techniques such as preoperative localization with SRS and intraoperative localization with duodenotomy have improved the effectiveness of surgical intervention for ZES. Future directions for investigation should include better defining the role of preoperative EUS and developing new, more sensitive techniques for preoperative localization. More research also is needed to define the appropriate indications for pancreaticoduodenectomy in ZES and to determine whether proximal vagotomy should be performed at the time of surgical exploration.

Pancreatic adenocarcinoma: why and when should it be resected?

PubMed Central

Ravichandran, D.; Johnson, C. D.

1997-01-01

Adenocarcinoma of the pancreas is a common and dreadful disease with an extremely poor prognosis. In practice, only a few patients are cured but surgical resection, although feasible in less than 20% of patients, offers maximum prolongation of life and provides good palliation of symptoms. This can now be performed safely, even in elderly patients, in specialist units. Better radiological imaging and laparoscopy allow selection of resectable tumours effectively. All patient with pancreatic cancer should now be assessed for surgical resection and potentially suitable patients should be referred to a specialist team at an early stage. Images Figure PMID:9307737

Next generation interatomic potentials for condensed systems

NASA Astrophysics Data System (ADS)

Handley, Christopher Michael; Behler, Jörg

2014-07-01

The computer simulation of condensed systems is a challenging task. While electronic structure methods like density-functional theory (DFT) usually provide a good compromise between accuracy and efficiency, they are computationally very demanding and thus applicable only to systems containing up to a few hundred atoms. Unfortunately, many interesting problems require simulations to be performed on much larger systems involving thousands of atoms or more. Consequently, more efficient methods are urgently needed, and a lot of effort has been spent on the development of a large variety of potentials enabling simulations with significantly extended time and length scales. Most commonly, these potentials are based on physically motivated functional forms and thus perform very well for the applications they have been designed for. On the other hand, they are often highly system-specific and thus cannot easily be transferred from one system to another. Moreover, their numerical accuracy is restricted by the intrinsic limitations of the imposed functional forms. In recent years, several novel types of potentials have emerged, which are not based on physical considerations. Instead, they aim to reproduce a set of reference electronic structure data as accurately as possible by using very general and flexible functional forms. In this review we will survey a number of these methods. While they differ in the choice of the employed mathematical functions, they all have in common that they provide high-quality potential-energy surfaces, while the efficiency is comparable to conventional empirical potentials. It has been demonstrated that in many cases these potentials now offer a very interesting new approach to study complex systems with hitherto unreached accuracy.

Preliminary study of ergonomic behavior during simulated ultrasound-guided regional anesthesia using a head-mounted display.

PubMed

Udani, Ankeet D; Harrison, T Kyle; Howard, Steven K; Kim, T Edward; Brock-Utne, John G; Gaba, David M; Mariano, Edward R

2012-08-01

A head-mounted display provides continuous real-time imaging within the practitioner's visual field. We evaluated the feasibility of using head-mounted display technology to improve ergonomics in ultrasound-guided regional anesthesia in a simulated environment. Two anesthesiologists performed an equal number of ultrasound-guided popliteal-sciatic nerve blocks using the head-mounted display on a porcine hindquarter, and an independent observer assessed each practitioner's ergonomics (eg, head turning, arching, eye movements, and needle manipulation) and the overall block quality based on the injectate spread around the target nerve for each procedure. Both practitioners performed their procedures without directly viewing the ultrasound monitor, and neither practitioner showed poor ergonomic behavior. Head-mounted display technology may offer potential advantages during ultrasound-guided regional anesthesia.

Fe-Catalyzed Synthesis of Porous Carbons Spheres with High Graphitization Degree for High-Performance Supercapacitors

NASA Astrophysics Data System (ADS)

Zhu, Jun; Shi, Hongwei; Zhuo, Xin; Hu, Yalin

2017-10-01

We have developed a facile and efficient Fe-catalyzed method for fabrication of porous carbons spheres with high graphitization degree (GNPCs) using glucose as carbon precursor at relatively low carbonization temperature. GNPCs not only have relatively large accessible ion surface area to accommodate greater capacity but also high graphitization degree to accelerate ion diffusion. As a typical application, we demonstrate that GNPCs exhibit excellent electrochemical performance for use in supercapacitors, with high specific capacity of 150.6 F g-1 at current density of 1 A g-1 and good rate capability and superior cycling stability over 10,000 cycles, confirming their potential application for energy storage. Moreover, it is believed that this method offers a new strategy for synthesis of porous carbons with high graphitization degree.

Supercritical Fluids Processing of Biomass to Chemicals and Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olson, Norman K.

2011-09-28

The main objective of this project is to develop and/or enhance cost-effective methodologies for converting biomass into a wide variety of chemicals, fuels, and products using supercritical fluids. Supercritical fluids will be used both to perform reactions of biomass to chemicals and products as well as to perform extractions/separations of bio-based chemicals from non-homogeneous mixtures. This work supports the Biomass Program’s Thermochemical Platform Goals. Supercritical fluids are a thermochemical approach to processing biomass that, while aligned with the Biomass Program’s interests in gasification and pyrolysis, offer the potential for more precise and controllable reactions. Indeed, the literature with respect tomore » the use of water as a supercritical fluid frequently refers to “supercritical water gasification” or “supercritical water pyrolysis.”« less

Modeling and investigation of refrigeration system performance with two-phase fluid injection in a scroll compressor

NASA Astrophysics Data System (ADS)

Gu, Rui

Vapor compression cycles are widely used in heating, refrigerating and air-conditioning. A slight performance improvement in the components of a vapor compression cycle, such as the compressor, can play a significant role in saving energy use. However, the complexity and cost of these improvements can block their application in the market. Modifying the conventional cycle configuration can offer a less complex and less costly alternative approach. Economizing is a common modification for improving the performance of the refrigeration cycle, resulting in decreasing the work required to compress the gas per unit mass. Traditionally, economizing requires multi-stage compressors, the cost of which has restrained the scope for practical implementation. Compressors with injection ports, which can be used to inject economized refrigerant during the compression process, introduce new possibilities for economization with less cost. This work focuses on computationally investigating a refrigeration system performance with two-phase fluid injection, developing a better understanding of the impact of injected refrigerant quality on refrigeration system performance as well as evaluating the potential COP improvement that injection provides based on refrigeration system performance provided by Copeland.

Performance Scripts Creation: Processes and Applications

ERIC Educational Resources Information Center

Lyons, Paul

2006-01-01

Purpose: Seeks to explain some of the dynamics of scripts creation as used in training, to offer some theoretical underpinning regarding the influence of script creation on behavior and performance, and to offer some examples of how script creation is applied in training activities. Design/methodology/approach: The paper explains in detail and…

Business Models for Training and Performance Improvement Departments

ERIC Educational Resources Information Center

Carliner, Saul

2004-01-01

Although typically applied to entire enterprises, the concept of business models applies to training and performance improvement groups. Business models are "the method by which firm[s] build and use [their] resources to offer.. value." Business models affect the types of projects, services offered, skills required, business processes, and type of…

The Entrepreneurship Education and Academic Performance

ERIC Educational Resources Information Center

Nasrullah, Shazia; Khan, Muhammad Saqib; Khan, Irfanullah

2016-01-01

The current study will be conducted in relationship of entrepreneurship education and academic performance. The study will be conducted on the post graduate students in the Universities of Bahawalpur. In the current study those universities will be included that were offering and also not offering entrepreneurship as a subject of teaching. The…

Field emitter displays for future avionics applications

NASA Astrophysics Data System (ADS)

Jones, Susan K.; Jones, Gary W.; Zimmerman, Steven M.; Blazejewski, Edward R.

1995-06-01

Field emitter array-based display technology offers CRT-like characteristics in a thin flat-panel display with many potential applications for vehicle-mounted, crew workstation, and helmet-mounted displays, as well as many other military and commercial applications. In addition to thinness, high brightness, wide viewing angle, wide temperature range, and low weight, field emitter array displays also offer potential advantages such as row-at-a-time matrix addressability and the ability to be segmented.

Synchronization of autonomous objects in discrete event simulation

NASA Technical Reports Server (NTRS)

Rogers, Ralph V.

1990-01-01

Autonomous objects in event-driven discrete event simulation offer the potential to combine the freedom of unrestricted movement and positional accuracy through Euclidean space of time-driven models with the computational efficiency of event-driven simulation. The principal challenge to autonomous object implementation is object synchronization. The concept of a spatial blackboard is offered as a potential methodology for synchronization. The issues facing implementation of a spatial blackboard are outlined and discussed.

Modification of Encapsulation Pressure of Reverse Micelles in Liquid Ethane

PubMed Central

Peterson, Ronald W.; Nucci, Nathaniel V.; Wand, A. Joshua

2011-01-01

Encapsulation of within reverse micelles dissolved in low viscosity fluids offers a potential solution to the slow tumbling problem presented by large soluble macromolecules to solution NMR spectroscopy. The reduction in effective macromolecular tumbling is directly dependent upon the viscosity of the solvent. Liquid ethane is of sufficiently low viscosity at pressures below 5,000 p.s.i. to offer a significant advantage. Unfortunately, the viscosity of liquid ethane shows appreciable pressure dependence. Reverse micelle encapsulation in liquid ethane often requires significantly higher pressures, which obviates the potential advantages offered by liquid ethane over liquid propane. Addition of co-surfactants or co-solvents can be used to manipulate the minimum pressure required to obtain stable, well-behaved solutions of reverse micelles prepared in liquid ethane. A library of potential additives is examined and several candidates suitable for use with encapsulated proteins are described. PMID:21764613

Modification of encapsulation pressure of reverse micelles in liquid ethane.

PubMed

Peterson, Ronald W; Nucci, Nathaniel V; Wand, A Joshua

2011-09-01

Encapsulation within reverse micelles dissolved in low viscosity fluids offers a potential solution to the slow tumbling problem presented by large soluble macromolecules to solution NMR spectroscopy. The reduction in effective macromolecular tumbling is directly dependent upon the viscosity of the solvent. Liquid ethane is of sufficiently low viscosity at pressures below 5000 psi to offer a significant advantage. Unfortunately, the viscosity of liquid ethane shows appreciable pressure dependence. Reverse micelle encapsulation in liquid ethane often requires significantly higher pressures, which obviates the potential advantages offered by liquid ethane over liquid propane. Addition of co-surfactants or co-solvents can be used to manipulate the minimum pressure required to obtain stable, well-behaved solutions of reverse micelles prepared in liquid ethane. A library of potential additives is examined and several candidates suitable for use with encapsulated proteins are described. Copyright © 2011 Elsevier Inc. All rights reserved.

Why does offspring size affect performance? Integrating metabolic scaling with life-history theory

PubMed Central

Pettersen, Amanda K.; White, Craig R.; Marshall, Dustin J.

2015-01-01

Within species, larger offspring typically outperform smaller offspring. While the relationship between offspring size and performance is ubiquitous, the cause of this relationship remains elusive. By linking metabolic and life-history theory, we provide a general explanation for why larger offspring perform better than smaller offspring. Using high-throughput respirometry arrays, we link metabolic rate to offspring size in two species of marine bryozoan. We found that metabolism scales allometrically with offspring size in both species: while larger offspring use absolutely more energy than smaller offspring, larger offspring use proportionally less of their maternally derived energy throughout the dependent, non-feeding phase. The increased metabolic efficiency of larger offspring while dependent on maternal investment may explain offspring size effects—larger offspring reach nutritional independence (feed for themselves) with a higher proportion of energy relative to structure than smaller offspring. These findings offer a potentially universal explanation for why larger offspring tend to perform better than smaller offspring but studies on other taxa are needed. PMID:26559952

Integrating Reconfigurable Hardware-Based Grid for High Performance Computing

PubMed Central

Dondo Gazzano, Julio; Sanchez Molina, Francisco; Rincon, Fernando; López, Juan Carlos

2015-01-01

FPGAs have shown several characteristics that make them very attractive for high performance computing (HPC). The impressive speed-up factors that they are able to achieve, the reduced power consumption, and the easiness and flexibility of the design process with fast iterations between consecutive versions are examples of benefits obtained with their use. However, there are still some difficulties when using reconfigurable platforms as accelerator that need to be addressed: the need of an in-depth application study to identify potential acceleration, the lack of tools for the deployment of computational problems in distributed hardware platforms, and the low portability of components, among others. This work proposes a complete grid infrastructure for distributed high performance computing based on dynamically reconfigurable FPGAs. Besides, a set of services designed to facilitate the application deployment is described. An example application and a comparison with other hardware and software implementations are shown. Experimental results show that the proposed architecture offers encouraging advantages for deployment of high performance distributed applications simplifying development process. PMID:25874241

Exceptional power density and stability at intermediate temperatures in protonic ceramic fuel cells

NASA Astrophysics Data System (ADS)

Choi, Sihyuk; Kucharczyk, Chris J.; Liang, Yangang; Zhang, Xiaohang; Takeuchi, Ichiro; Ji, Ho-Il; Haile, Sossina M.

2018-03-01

Over the past several years, important strides have been made in demonstrating protonic ceramic fuel cells (PCFCs). Such fuel cells offer the potential of environmentally sustainable and cost-effective electric power generation. However, their power outputs have lagged behind predictions based on their high electrolyte conductivities. Here we overcome PCFC performance and stability challenges by employing a high-activity cathode, PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF), in combination with a chemically stable electrolyte, BaZr0.4Ce0.4Y0.1Yb0.1O3 (BZCYYb4411). We deposit a thin dense interlayer film of the cathode material onto the electrolyte surface to mitigate contact resistance, an approach which is made possible by the proton permeability of PBSCF. The peak power densities of the resulting fuel cells exceed 500 mW cm-2 at 500 °C, while also offering exceptional, long-term stability under CO2.

Direct Detection Electron Energy-Loss Spectroscopy: A Method to Push the Limits of Resolution and Sensitivity.

PubMed

Hart, James L; Lang, Andrew C; Leff, Asher C; Longo, Paolo; Trevor, Colin; Twesten, Ray D; Taheri, Mitra L

2017-08-15

In many cases, electron counting with direct detection sensors offers improved resolution, lower noise, and higher pixel density compared to conventional, indirect detection sensors for electron microscopy applications. Direct detection technology has previously been utilized, with great success, for imaging and diffraction, but potential advantages for spectroscopy remain unexplored. Here we compare the performance of a direct detection sensor operated in counting mode and an indirect detection sensor (scintillator/fiber-optic/CCD) for electron energy-loss spectroscopy. Clear improvements in measured detective quantum efficiency and combined energy resolution/energy field-of-view are offered by counting mode direct detection, showing promise for efficient spectrum imaging, low-dose mapping of beam-sensitive specimens, trace element analysis, and time-resolved spectroscopy. Despite the limited counting rate imposed by the readout electronics, we show that both core-loss and low-loss spectral acquisition are practical. These developments will benefit biologists, chemists, physicists, and materials scientists alike.

Frequency-encoded photonic qubits for scalable quantum information processing

DOE PAGES

Lukens, Joseph M.; Lougovski, Pavel

2016-12-21

Among the objectives for large-scale quantum computation is the quantum interconnect: a device that uses photons to interface qubits that otherwise could not interact. However, the current approaches require photons indistinguishable in frequency—a major challenge for systems experiencing different local environments or of different physical compositions altogether. Here, we develop an entirely new platform that actually exploits such frequency mismatch for processing quantum information. Labeled “spectral linear optical quantum computation” (spectral LOQC), our protocol offers favorable linear scaling of optical resources and enjoys an unprecedented degree of parallelism, as an arbitrary Ν-qubit quantum gate may be performed in parallel onmore » multiple Ν-qubit sets in the same linear optical device. Here, not only does spectral LOQC offer new potential for optical interconnects, but it also brings the ubiquitous technology of high-speed fiber optics to bear on photonic quantum information, making wavelength-configurable and robust optical quantum systems within reach.« less

Frequency-encoded photonic qubits for scalable quantum information processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lukens, Joseph M.; Lougovski, Pavel

Among the objectives for large-scale quantum computation is the quantum interconnect: a device that uses photons to interface qubits that otherwise could not interact. However, the current approaches require photons indistinguishable in frequency—a major challenge for systems experiencing different local environments or of different physical compositions altogether. Here, we develop an entirely new platform that actually exploits such frequency mismatch for processing quantum information. Labeled “spectral linear optical quantum computation” (spectral LOQC), our protocol offers favorable linear scaling of optical resources and enjoys an unprecedented degree of parallelism, as an arbitrary Ν-qubit quantum gate may be performed in parallel onmore » multiple Ν-qubit sets in the same linear optical device. Here, not only does spectral LOQC offer new potential for optical interconnects, but it also brings the ubiquitous technology of high-speed fiber optics to bear on photonic quantum information, making wavelength-configurable and robust optical quantum systems within reach.« less

Perinatal exposure to music protects spatial memory against callosal lesions.

PubMed

Amagdei, Anca; Balteş, Felicia Rodica; Avram, Julia; Miu, Andrei C

2010-02-01

Several studies have indicated that the exposure of rodents to music modulates brain development and neuroplasticity, by mechanisms that involve facilitated hippocampal neurogenesis, neurotrophin synthesis and glutamatergic signaling. This study focused on the potential protection that the perinatal exposure to music, between postnatal days 2 and 32, could offer against functional deficits induced by neonatal callosotomy in rats. The spontaneous alternation and marble-burying behaviors were longitudinally measured in callosotomized and control rats that had been exposed to music or not. The results indicated that the neonatal callosotomy-induced spontaneous alternation deficits that became apparent only after postnatal day 45, about the time when the rat corpus callosum reaches its maximal levels of myelination. The perinatal exposure to music efficiently protected the spontaneous alternation performance against the deficits induced by callosotomy. The present findings may offer important insights into music-induced neuroplasticity, relevant to brain development and neurorehabilitation. Copyright 2009 ISDN. Published by Elsevier Ltd. All rights reserved.

Reconstruction of fluorophore concentration variation in dynamic fluorescence molecular tomography.

PubMed

Zhang, Xuanxuan; Liu, Fei; Zuo, Simin; Shi, Junwei; Zhang, Guanglei; Bai, Jing; Luo, Jianwen

2015-01-01

Dynamic fluorescence molecular tomography (DFMT) is a potential approach for drug delivery, tumor detection, diagnosis, and staging. The purpose of DFMT is to quantify the changes of fluorescent agents in the bodies, which offer important information about the underlying physiological processes. However, the conventional method requires that the fluorophore concentrations to be reconstructed are stationary during the data collection period. As thus, it cannot offer the dynamic information of fluorophore concentration variation within the data collection period. In this paper, a method is proposed to reconstruct the fluorophore concentration variation instead of the fluorophore concentration through a linear approximation. The fluorophore concentration variation rate is introduced by the linear approximation as a new unknown term to be reconstructed and is used to obtain the time courses of fluorophore concentration. Simulation and phantom studies are performed to validate the proposed method. The results show that the method is able to reconstruct the fluorophore concentration variation rates and the time courses of fluorophore concentration with relative errors less than 0.0218.

Performance of draught cattle in communal farming areas in Zimbabwe after dry season supplementation.

PubMed

Ndlovu, L R; Francis, J; Hove, E

1996-11-01

Sixty-four pairs of oxen owned by smallholders were randomly allocated to one of 3 supplementary treatments offered at one kg per head per day from July to October or to a control where no supplement was offered. The supplements were maize stover plus silverleaf hay (2:1 w/w), urea-treated maize stover (50 g urea/kg stover) and plain maize stover. Animals fed plain maize stover or no supplement lost weight (6 to 7% of initial weight), whilst those fed the other 2 supplements maintained their liveweights. Supplementation reduced time spent on feeding activities by 10 per cent. Animals fed on urea-treated maize stover or maize stover plus silverleaf hay ploughed at speeds that were 29% faster than oxen on the other treatments and covered 45% more area. Blood parameters indicated a general deficiency of nitrogen intake throughout the dry season. It was concluded that supplements of good quality have the potential to improve the working ability of communal area oxen.

Applications of Microalgal Biotechnology for Disease Control in Aquaculture.

PubMed

Charoonnart, Patai; Purton, Saul; Saksmerprome, Vanvimon

2018-04-12

Aquaculture industries, and in particular the farming of fish and crustaceans, are major contributors to the economy of many countries and an increasingly important component in global food supply. However, the severe impact of aquatic microbial diseases on production performance remains a challenge to these industries. This article considers the potential applications of microalgal technology in the control of such diseases. At the simplest level, microalgae offer health-promoting benefits as a nutritional supplement in feed meal because of their digestibility and high content of proteins, lipids and essential nutrients. Furthermore, some microalgal species possess natural anti-microbial compounds or contain biomolecules that can serve as immunostimulants. In addition, emerging genetic engineering technologies in microalgae offer the possibility of producing 'functional feed additives' in which novel and specific bioactives, such as fish growth hormones, anti-bacterials, subunit vaccines, and virus-targeted interfering RNAs, are components of the algal supplement. The evaluation of such technologies for farm applications is an important step in the future development of sustainable aquaculture.

High-quality ultrastructural preservation using cryofixation for 3D electron microscopy of genetically labeled tissues

PubMed Central

Boassa, Daniela; Hu, Junru; Romoli, Benedetto; Phan, Sebastien; Dulcis, Davide

2018-01-01

Electron microscopy (EM) offers unparalleled power to study cell substructures at the nanoscale. Cryofixation by high-pressure freezing offers optimal morphological preservation, as it captures cellular structures instantaneously in their near-native state. However, the applicability of cryofixation is limited by its incompatibility with diaminobenzidine labeling using genetic EM tags and the high-contrast en bloc staining required for serial block-face scanning electron microscopy (SBEM). In addition, it is challenging to perform correlated light and electron microscopy (CLEM) with cryofixed samples. Consequently, these powerful methods cannot be applied to address questions requiring optimal morphological preservation. Here, we developed an approach that overcomes these limitations; it enables genetically labeled, cryofixed samples to be characterized with SBEM and 3D CLEM. Our approach is broadly applicable, as demonstrated in cultured cells, Drosophila olfactory organ and mouse brain. This optimization exploits the potential of cryofixation, allowing for quality ultrastructural preservation for diverse EM applications. PMID:29749931

Wavelet images and Chou's pseudo amino acid composition for protein classification.

PubMed

Nanni, Loris; Brahnam, Sheryl; Lumini, Alessandra

2012-08-01

The last decade has seen an explosion in the collection of protein data. To actualize the potential offered by this wealth of data, it is important to develop machine systems capable of classifying and extracting features from proteins. Reliable machine systems for protein classification offer many benefits, including the promise of finding novel drugs and vaccines. In developing our system, we analyze and compare several feature extraction methods used in protein classification that are based on the calculation of texture descriptors starting from a wavelet representation of the protein. We then feed these texture-based representations of the protein into an Adaboost ensemble of neural network or a support vector machine classifier. In addition, we perform experiments that combine our feature extraction methods with a standard method that is based on the Chou's pseudo amino acid composition. Using several datasets, we show that our best approach outperforms standard methods. The Matlab code of the proposed protein descriptors is available at http://bias.csr.unibo.it/nanni/wave.rar .

Assessment of executive function in adolescence: a comparison of traditional and virtual reality tools.

PubMed

Lalonde, Gabrielle; Henry, Mylène; Drouin-Germain, Anne; Nolin, Pierre; Beauchamp, Miriam H

2013-09-30

Paper-pencil type tests are traditionally used in the assessment of executive functions (EF); however, concerns have been raised as to whether these represent actual functioning in everyday life. Virtual reality (VR) environments offer a novel alternative for the assessment of cognitive function and therefore have the potential to enhance the evaluation of EF by presenting individuals with stimuli that come closer to reproducing everyday situations. The aims of this study were to (1) establish which traditional paper-pencil EF tests from the Delis-Kaplan Executive Function System (D-KEFS) are associated with performance on a VR-Stroop task and (2) compare D-KEFS tests and the VR-Stroop task in their ability to predict everyday EF and behavior, as measured by the Behavioral Rating Inventory of Executive Function (BRIEF) and the Child Behavior Checklist (CBCL). Thirty-eight typically developing adolescents aged between 13 and 17 years completed the ClinicaVR: Classroom-Stroop, and five D-KEFS subtests (Trail Making, Tower, Twenty Questions, Verbal Fluency and Color-Word Interference). Their parents completed the BRIEF and CBCL questionnaires. The results indicate that performance on the VR-Stroop task correlates with both traditional forms of EF assessment (D-KEFS, BRIEF). In particular, performance on the VR-Stroop task was closely associated with performance on a paper-pencil inhibition task. Furthermore, VR-Stroop performance more accurately reflected everyday behavioral EF than paper-pencil tasks. VR appears to offer an ecological perspective on everyday functioning and could be seen as complementary to traditional tests in the assessment of complex cognitive abilities. Copyright © 2013 Elsevier B.V. All rights reserved.

IOC Consensus Statement: Dietary Supplements and the High-Performance Athlete.

PubMed

Maughan, Ronald J; Burke, Louise M; Dvorak, Jiri; Larson-Meyer, D Enette; Peeling, Peter; Phillips, Stuart M; Rawson, Eric S; Walsh, Neil P; Garthe, Ina; Geyer, Hans; Meeusen, Romain; van Loon, Luc; Shirreffs, Susan M; Spriet, Lawrence L; Stuart, Mark; Vernec, Alan; Currell, Kevin; Ali, Vidya M; Budgett, Richard G M; Ljungqvist, Arne; Mountjoy, Margo; Pitsiladis, Yannis; Soligard, Torbjørn; Erdener, Uğur; Engebretsen, Lars

2018-03-01

Nutrition usually makes a small but potentially valuable contribution to successful performance in elite athletes, and dietary supplements can make a minor contribution to this nutrition program. Nonetheless, supplement use is widespread at all levels of sport. Products described as supplements target different issues, including the management of micronutrient deficiencies, supply of convenient forms of energy and macronutrients, and provision of direct benefits to performance or indirect benefits such as supporting intense training regimens. The appropriate use of some supplements can offer benefits to the athlete, but others may be harmful to the athlete's health, performance, and/or livelihood and reputation if an anti-doping rule violation results. A complete nutritional assessment should be undertaken before decisions regarding supplement use are made. Supplements claiming to directly or indirectly enhance performance are typically the largest group of products marketed to athletes, but only a few (including caffeine, creatine, specific buffering agents and nitrate) have good evidence of benefits. However, responses are affected by the scenario of use and may vary widely between individuals because of factors that include genetics, the microbiome, and habitual diet. Supplements intended to enhance performance should be thoroughly trialed in training or simulated competition before implementation in competition. Inadvertent ingestion of substances prohibited under the anti-doping codes that govern elite sport is a known risk of taking some supplements. Protection of the athlete's health and awareness of the potential for harm must be paramount, and expert professional opinion and assistance is strongly advised before embarking on supplement use.

Quantifying Phishing Susceptibility for Detection and Behavior Decisions.

PubMed

Canfield, Casey Inez; Fischhoff, Baruch; Davis, Alex

2016-12-01

We use signal detection theory to measure vulnerability to phishing attacks, including variation in performance across task conditions. Phishing attacks are difficult to prevent with technology alone, as long as technology is operated by people. Those responsible for managing security risks must understand user decision making in order to create and evaluate potential solutions. Using a scenario-based online task, we performed two experiments comparing performance on two tasks: detection, deciding whether an e-mail is phishing, and behavior, deciding what to do with an e-mail. In Experiment 1, we manipulated the order of the tasks and notification of the phishing base rate. In Experiment 2, we varied which task participants performed. In both experiments, despite exhibiting cautious behavior, participants' limited detection ability left them vulnerable to phishing attacks. Greater sensitivity was positively correlated with confidence. Greater willingness to treat e-mails as legitimate was negatively correlated with perceived consequences from their actions and positively correlated with confidence. These patterns were robust across experimental conditions. Phishing-related decisions are sensitive to individuals' detection ability, response bias, confidence, and perception of consequences. Performance differs when people evaluate messages or respond to them but not when their task varies in other ways. Based on these results, potential interventions include providing users with feedback on their abilities and information about the consequences of phishing, perhaps targeting those with the worst performance. Signal detection methods offer system operators quantitative assessments of the impacts of interventions and their residual vulnerability. © 2016, Human Factors and Ergonomics Society.

Oxide_Oxide Ceramic Matrix Composite (CMC) Exhaust Mixer Development in the NASA Environmentally Responsible Aviation (ERA) Project

NASA Technical Reports Server (NTRS)

Kiser, J. Douglas; Bansal, Narottam P.; Szelagowski, James; Sokhey, Jagdish; Heffernan, Tab; Clegg, Joseph; Pierluissi, Anthony; Riedell, Jim; Wyen, Travis; Atmur, Steven;

Effects of group status and victim sex on female bystanders' responses to a potential party rape.

PubMed

Katz, Jennifer; Colbert, Samuel; Colangelo, Liane

2015-01-01

This research examined bystander responses to 1 of 4 potential party rape scenarios. Undergraduate women (N = 249) imagined attending a party either alone or with three friends where a sober man led an intoxicated potential victim (either male or female) into a bedroom. After random assignment to conditions, participants reported on intent to help and barriers to helping the potential victim. In contrast to the classic bystander effect, bystanders in groups intended to offer more help than lone bystanders. Bystanders also intended to offer more help to potential female than male victims and experienced more barriers to helping male victims. Two of these barriers (lack of personal responsibility to help and identifying risk) explained the lower intentions to help potential male victims. Potential male victims were more likely than female victims to be perceived as gay, and bystanders reported the least intentions to help presumably gay men at risk.

Self-sensing performance of MWCNT-low density polyethylene nanocomposites

NASA Astrophysics Data System (ADS)

Gupta, Tejendra K.; Kumar, S.; Khan, Amal Z.; Varadarajan, Kartik M.; Cantwell, Wesley J.

2018-01-01

Carbon nanotubes (CNTs) based polymer nanocomposites offer a range of remarkable properties. Here, we demonstrate self-sensing performance of low density polyethylene (LDPE)-multiwalled carbon nanotubes (MWCNTs) nanocomposites for the first time. The dispersion of the CNTs and the morphology of the nanocomposites was investigated using scanning electron microscopy, x-ray diffraction and Raman spectroscopic techniques. The thermal properties were measured using thermal gravimetric analysis and differential scanning calorimetry and were found to increase with increasing wt% of MWCNTs in LDPE matrix. An overall improvement in ultimate tensile strength, yield strength and Young’s modulus was found to be 59.6%, 48.5% and 129.3%, respectively for 5.0 wt% loading of MWCNTs. The electrical percolation threshold was observed at 1.0 wt% of MWCNTs and the highest electrical conductivity of 2.8 × 10-2 Scm-1 was observed at 5.0 wt% loading of MWCNTs. These piezo-resistive nanocomposites offer tunable self-sensing capabilities with gauge factors in the ranges of 17-52 and 42-530 in linear elastic (strain ˜3%) and inelastic regimes (strain ˜15%) respectively. Our demonstration would provide guidelines for the fabrication of low cost, self-sensing MWCNT-LDPE nanocomposites for potential use as civil water pipelines and landfill membranes.

A novel approach for reliable detection of cathepsin S activities in mouse antigen presenting cells.

PubMed

Steimle, Alex; Kalbacher, Hubert; Maurer, Andreas; Beifuss, Brigitte; Bender, Annika; Schäfer, Andrea; Müller, Ricarda; Autenrieth, Ingo B; Frick, Julia-Stefanie

2016-05-01

Cathepsin S (CTSS) is a eukaryotic protease mostly expressed in professional antigen presenting cells (APCs). Since CTSS activity regulation plays a role in the pathogenesis of various autoimmune diseases like multiple sclerosis, atherosclerosis, Sjögren's syndrome and psoriasis as well as in cancer progression, there is an ongoing interest in the reliable detection of cathepsin S activity. Various applications have been invented for specific detection of this enzyme. However, most of them have only been shown to be suitable for human samples, do not deliver quantitative results or the experimental procedure requires technical equipment that is not commonly available in a standard laboratory. We have tested a fluorogen substrate, Mca-GRWPPMGLPWE-Lys(Dnp)-DArg-NH2, that has been described to specifically detect CTSS activities in human APCs for its potential use for mouse samples. We have modified the protocol and thereby offer a cheap, easy, reproducible and quick activity assay to detect CTSS activities in mouse APCs. Since most of basic research on CTSS is performed in mice, this method closes a gap and offers a possibility for reliable and quantitative CTSS activity detection that can be performed in almost every laboratory. Copyright © 2016. Published by Elsevier B.V.

Scalable Fabrication of High-Performance Transparent Conductors Using Graphene Oxide-Stabilized Single-Walled Carbon Nanotube Inks

PubMed Central

He, Linxiang; Liao, Chengzhu

2018-01-01

Recent development in liquid-phase processing of single-walled carbon nanotubes (SWNTs) has revealed rod-coating as a promising approach for large-scale production of SWNT-based transparent conductors. Of great importance in the ink formulation is the stabilizer having excellent dispersion stability, environmental friendly and tunable rheology in the liquid state, and also can be readily removed to enhance electrical conductivity and mechanical stability. Herein we demonstrate the promise of graphene oxide (GO) as a synergistic stabilizer for SWNTs in water. SWNTs dispersed in GO is formulated into inks with homogeneous nanotube distribution, good wetting and rheological properties, and compatible with industrial rod coating practice. Microwave treatment of rod-coated films can reduce GOs and enhance electro-optical performance. The resultant films offer a sheet resistance of ~80 Ω/sq at 86% transparency, along with good mechanical flexibility. Doping the films with nitric acid can further decrease the sheet resistance to ~25 Ω/sq. Comparing with the films fabricated from typical surfactant-based SWNT inks, our films offer superior adhesion as assessed by the Scotch tape test. This study provides new insight into the selection of suitable stabilizers for functional SWNT inks with strong potential for printed electronics. PMID:29642446

Vertical-cavity surface-emitting lasers: the applications

NASA Astrophysics Data System (ADS)

Morgan, Robert A.; Lehman, John A.; Hibbs-Brenner, Mary K.; Liu, Yue; Bristow, Julian P. G.

1997-05-01

In this paper, we focus on how vertical-cavity surface- emitting lasers (VCSELs) and arrays have led to many feasible advanced technological applications. Their intrinsic characteristics, performance, and producibility offer substantial advantages over alternative sources. Demonstrated performance of `commercial-grade' VCSELs include low operating powers (< 2 V, mAs), high speeds (3 dB BWs > 15 GHz), and high temperature operating ranges (10 K to 400 K and -55 degree(s)C to 125 degree(s)C, and T > 200 degree(s)C). Moreover, their robustness is manifest by high reliability in excess of 107 hours mean time between failures at room temperature and tenfold improvement over existing rad-hard LEDs. Hence, even these `commercial-grade' VCSELs offer potential within cryogenic and avionics/military or space environments. We have also demonstrated submilliamp ITH, stable, single-mode VCSELs utilized within bias-free 1-Gbit/s data links. These low- power VCSELs may also serve in applications from printers to low-cost atomic clocks. The greatest near-term VCSEL applications are upgrades to low-cost LEDs and high-grade copper wire in data links and sensors. Exploiting their surface-emitting geometry, VCSELs are also compatible with established multichip module packaging. Hence VCSELs and VCSEL arrays are ideal components for interconnect-intensive processing applications between and within computing systems.

Comparison of cemented and uncemented fixation in total knee arthroplasty.

PubMed

Brown, Thomas E; Harper, Benjamin L; Bjorgul, Kristian

2013-05-01

As a result of reading this article, physicians should be able to :1. Understand the rationale behind using uncemented fixation in total knee arthroplasty.2.Discuss the current literature comparing cemented and uncemented total knee arthroplasty3. Describe the value of radiostereographic analysis in assessing implant stability.4. Appreciate the limitations in the available literature advocating 1 mode of fixation in total knee arthroplasty. Total knee arthroplasty performed worldwide uses either cemented, cementless, or hybrid (cementless femur with a cemented tibia) fixation of the components. No recent literature review concerning the outcomes of cemented vs noncemented components has been performed. Noncemented components offer the potential advantage of a biologic interface between the bone and implants, which could demonstrate the greatest advantage in long-term durable fixation in the follow-up of young patients undergoing arthroplasty. Several advances have been made in the backing of the tibial components that have not been available long enough to yield long-term comparative follow-up studies. Short-term radiostereographic analysis studies have yielded differing results. Although long-term, high-quality studies are still needed, material advances in biologic fixation surfaces, such as trabecular metal and hydroxyapatite, may offer promising results for young and active patients undergoing total knee arthroplasty when compared with traditional cemented options. Copyright 2013, SLACK Incorporated.

Hospital CEOs, CFOs, and nurse executives: opportunities for a new alliance.

PubMed

Dwore, R B; Murray, B P; Fosbinder, D; Parsons, R P; Smith, P; Dalley, K; Vorderer, L; Gustafson, G

1998-01-01

This article examines the involvement of Utah acute care hospital nurse executives (NEs) in financial management roles. The authors surveyed NEs and their career supporters and hinderers. Findings suggest that NFs: 1. lack financial management skills, support, involvement, and satisfaction; 2. recognize financial management's importance and desire to improve performance; and 3. consider chief executive officers (CEOs) as their major supporters and chief financial officers (CFOs) their major hinderers in financial management. These "supporters" and "hinderers" of NEs showed consensus regarding the primacy of NEs' leadership and patient advocacy roles. These findings contrast with major professional association policy directives and expert opinions that advocate expanded financial management roles for NEs that will enable them to fully realize their executive potential. CEOs are positioned to establish norms that balance the traditional leadership-patient advocacy roles of NEs with newer financial management roles. CEOs can offer NEs and CFOs opportunities to improve NEs' financial management participation and performance. CEOs can provide empowerment and encourage CFOs to offer NEs "power tools" (for example, information, expertise, resources, and support). The three groups, however, must negotiate reasonable expectations for NEs in financial management and adequate preparation for these consequent responsibilities. Together, CEOs, CFOs, and NEs can successfully take hospitals into the future by leading them in ongoing learning and change.

Smartphones for cell and biomolecular detection.

PubMed

Liu, Xiyuan; Lin, Tung-Yi; Lillehoj, Peter B

2014-11-01

Recent advances in biomedical science and technology have played a significant role in the development of new sensors and assays for cell and biomolecular detection. Generally, these efforts are aimed at reducing the complexity and costs associated with diagnostic testing so that it can be performed outside of a laboratory or hospital setting, requiring minimal equipment and user involvement. In particular, point-of-care (POC) testing offers immense potential for many important applications including medical diagnosis, environmental monitoring, food safety, and biosecurity. When coupled with smartphones, POC systems can offer portability, ease of use and enhanced functionality while maintaining performance. This review article focuses on recent advancements and developments in smartphone-based POC systems within the last 6 years with an emphasis on cell and biomolecular detection. These devices typically comprise multiple components, such as detectors, sample processors, disposable chips, batteries, and software, which are integrated with a commercial smartphone. One of the most important aspects of developing these systems is the integration of these components onto a compact and lightweight platform that requires minimal power. Researchers have demonstrated several promising approaches employing various detection schemes and device configurations, and it is expected that further developments in biosensors, battery technology and miniaturized electronics will enable smartphone-based POC technologies to become more mainstream tools in the scientific and biomedical communities.

Maritime microwave radar and electro-optical data fusion for homeland security

NASA Astrophysics Data System (ADS)

Seastrand, Mark J.

2004-09-01

US Customs is responsible for monitoring all incoming air and maritime traffic, including the island of Puerto Rico as a US territory. Puerto Rico offers potentially obscure points of entry to drug smugglers. This environment sets forth a formula for an illegal drug trade - based relatively near the continental US. The US Customs Caribbean Air and Marine Operations Center (CAMOC), located in Puntas Salinas, has the charter to monitor maritime and Air Traffic Control (ATC) radars. The CAMOC monitors ATC radars and advises the Air and Marine Branch of US Customs of suspicious air activity. In turn, the US Coast Guard and/or US Customs will launch air and sea assets as necessary. The addition of a coastal radar and camera system provides US Customs a maritime monitoring capability for the northwestern end of Puerto Rico (Figure 1). Command and Control of the radar and camera is executed at the CAMOC, located 75 miles away. The Maritime Microwave Surveillance Radar performs search, primary target acquisition and target tracking while the Midwave Infrared (MWIR) camera performs target identification. This wide area surveillance, using a combination of radar and MWIR camera, offers the CAMOC a cost and manpower effective approach to monitor, track and identify maritime targets.

Acoustic MIMO communications in a very shallow water channel

NASA Astrophysics Data System (ADS)

Zhou, Yuehai; Cao, Xiuling; Tong, Feng

2015-12-01

Underwater acoustic channels pose significant difficulty for the development of high speed communication due to highly limited band-width as well as hostile multipath interference. Enlightened by rapid progress of multiple input multiple output (MIMO) technologies in wireless communication scenarios, MIMO systems offer a potential solution by enabling multiple spatially parallel communication channels to improve communication performance as well as capacity. For MIMO acoustic communications, deep sea channels offer substantial spatial diversity among multiple channels that can be exploited to address simultaneous multipath and co-channel interference. At the same time, there are increasing requirements for high speed underwater communication in very shallow water area (for example, a depth less than 10 m). In this paper, a space-time multichannel adaptive receiver consisting of multiple decision feedback equalizers (DFE) is adopted as the receiver for a very shallow water MIMO acoustic communication system. The performance of multichannel DFE receivers with relatively small number of receiving elements are analyzed and compared with that of the multichannel time reversal receiver to evaluate the impact of limited spatial diversity on multi-channel equalization and time reversal processing. The results of sea trials in a very shallow water channel are presented to demonstrate the feasibility of very shallow water MIMO acoustic communication.

Techno-economic sensitivity study of heliostat field parameters for micro-gas turbine CSP

NASA Astrophysics Data System (ADS)

Landman, Willem A.; Gauché, Paul; Dinter, Frank; Myburgh, J. T.

2017-06-01

Concentrating solar power systems based on micro-gas turbines potentially offer numerous benefits should they become commercially viable. Heliostat fields for such systems have unique requirements in that the number of heliostats and the focal ratios are typically much lower than conventional central receiver systems. This paper presents a techno-economic sensitivity study of heliostat field parameters for a micro-gas turbine central receiver system. A 100 kWe minitower system is considered for the base case and a one-at-a-time strategy is used to investigate parameter sensitivities. Increasing heliostat focal ratios are found to have significant optical performance benefits due to both a reduction in astigmatic aberrations and a reduction in the number of facet focal lengths required; confirming the hypothesis that smaller heliostats offer a techno-economic advantage. Fixed Horizontal Axis tracking mechanism is shown to outperform the conventional Azimuth Zenith tracking mechanism in high density heliostat fields. Although several improvements to heliostat field performance are discussed, the capex fraction of the heliostat field for such system is shown to be almost half that of a conventional central receiver system and optimum utilization of the higher capex components, namely; the receiver and turbine subsystems, are more rewarding than that of the heliostat field.

Self-Reported Interest to Participate in a Health Survey if Different Amounts of Cash or Non-Monetary Incentive Types Were Offered.

PubMed

Zheng, Guili; Oksuzyan, Sona; Hsu, Shelly; Cloud, Jennifer; Jewell, Mirna Ponce; Shah, Nirvi; Smith, Lisa V; Frye, Douglas; Kuo, Tony

2018-04-13

The objective of this study was to assess monetary and non-monetary factors that can influence the decision to participate in a future health survey. A questionnaire was administered to eligible, low-income participants (n = 1502) of the 2012 Los Angeles County Health and Nutrition Examination Survey (LAHANES-II). Multivariable regression analyses were performed to describe factors potentially associated with future intent to participate in similar survey designs. The results of the survey suggest that, overall, female participants had a greater interest in participating under a variety of incentive scenarios. Compared to the 25-34 age group, older participants (35-44, 45-84) reported more interest to participate if $10 cash [prepaid gift/debit card], a coupon for product/travel, or a small item [e.g., granola bar, t-shirt, pen] was offered, whereas younger participants (18-24) reported greater interest for $25 cash or a coupon for product/travel. Non-Whites, when compared to Whites/Non-Hispanics, reported greater interest to participate if any of the incentives was offered. High school graduates, when compared to those with some college education, reported greater interest to participate if $10 cash, a small item, or a lottery ticket was offered. Presence of two or more chronic conditions increased interest while concerns about participation in LAHANES-II was associated with reduced interest to participate in future health-related surveys. The results suggest that both incentives and non-monetary considerations (e.g., personal concerns about participating and individual level characteristics) can influence the decision to participate in health-related surveys and offer insights into strategies that can improve response rates for these assessments that are often used to inform community planning.

Use of the Analysis of the Volatile Faecal Metabolome in Screening for Colorectal Cancer

PubMed Central

2015-01-01

Diagnosis of colorectal cancer is an invasive and expensive colonoscopy, which is usually carried out after a positive screening test. Unfortunately, existing screening tests lack specificity and sensitivity, hence many unnecessary colonoscopies are performed. Here we report on a potential new screening test for colorectal cancer based on the analysis of volatile organic compounds (VOCs) in the headspace of faecal samples. Faecal samples were obtained from subjects who had a positive faecal occult blood sample (FOBT). Subjects subsequently had colonoscopies performed to classify them into low risk (non-cancer) and high risk (colorectal cancer) groups. Volatile organic compounds were analysed by selected ion flow tube mass spectrometry (SIFT-MS) and then data were analysed using both univariate and multivariate statistical methods. Ions most likely from hydrogen sulphide, dimethyl sulphide and dimethyl disulphide are statistically significantly higher in samples from high risk rather than low risk subjects. Results using multivariate methods show that the test gives a correct classification of 75% with 78% specificity and 72% sensitivity on FOBT positive samples, offering a potentially effective alternative to FOBT. PMID:26086914

Cigarette promotional offers: who takes advantage?

PubMed

White, Victoria M; White, Martha M; Freeman, Karen; Gilpin, Elizabeth A; Pierce, John P

2006-03-01

Promotional offers on cigarettes (e.g., dollar-off, multipack discounts) composed the largest share of tobacco industry marketing expenditures, totaling $8.9 billion, or 72% of the total budget in 2002. Internal industry documents indicate that young adults, potential quitters, and other price-sensitive groups are the targets of these marketing tactics. How effective they are in actually reaching these groups in the general population of smokers has not yet been investigated. Data were from 4618 current smokers responding to the large, random-digit-dialed population-based 2002 California Tobacco Survey. The characteristics were identified of smokers who reported that they used these offers "every time I see one." Thirty-five percent of smokers used promotional offers every time they saw one. Multivariate analyses identified young adults, women, African Americans, those with higher daily cigarette consumption, and those worried about cigarette costs as more likely to use promotional offers at every opportunity. Smokers most committed to quitting were no more likely to use promotional offers than those with no intention to quit. Cigarette brand was highly correlated with age and race/ethnicity, and therefore was not included in the multivariate analysis. Those who smoked menthol cigarettes and Camels, more often young adults and African Americans, were much more likely than those of other brands to use promotional offers. With the exception of smokers intending to quit, cigarette promotional offers are effectively reaching most industry-targeted groups. Importantly, young adults, who have the greatest long-term customer potential, are responding.

Applied Cognitive Models of Behavior and Errors Patterns

DTIC Science & Technology

2017-09-01

methods offer an opportunity to deliver good , effective introductory and basic training , thus potentially enabling a single human instructor to train ...emergency medical technician (EMT) domain, which offers a standardized curriculum on which we can create training scenarios. 2. Develop...complexity of software integration and limited access to physical devices can result in commitment to a de- sign that turns out to not offer many training

Training for Template Creation: A Performance Improvement Method

ERIC Educational Resources Information Center

Lyons, Paul

2008-01-01

Purpose: There are three purposes to this article: first, to offer a training approach to employee learning and performance improvement that makes use of a step-by-step process of skill/knowledge creation. The process offers follow-up opportunities for skill maintenance and improvement; second, to explain the conceptual bases of the approach; and…

Marine Natural Products from New Caledonia—A Review

PubMed Central

Motuhi, Sofia-Eléna; Mehiri, Mohamed; Payri, Claude Elisabeth; La Barre, Stéphane; Bach, Stéphane

2016-01-01

Marine micro- and macroorganisms are well known to produce metabolites with high biotechnological potential. Nearly 40 years of systematic prospecting all around the New Caledonia archipelago and several successive research programs have uncovered new chemical leads from benthic and planktonic organisms. After species identification, biological and/or pharmaceutical analyses are performed on marine organisms to assess their bioactivities. A total of 3582 genera, 1107 families and 9372 species have been surveyed and more than 350 novel molecular structures have been identified. Along with their bioactivities that hold promise for therapeutic applications, most of these molecules are also potentially useful for cosmetics and food biotechnology. This review highlights the tremendous marine diversity in New Caledonia, and offers an outline of the vast possibilities for natural products, especially in the interest of pursuing collaborative fundamental research programs and developing local biotechnology programs. PMID:26999165

Introduction to the Special Issue: Advancing the State-of-the-Science in Reading Research through Modeling.

PubMed

Zevin, Jason D; Miller, Brett

Reading research is increasingly a multi-disciplinary endeavor involving more complex, team-based science approaches. These approaches offer the potential of capturing the complexity of reading development, the emergence of individual differences in reading performance over time, how these differences relate to the development of reading difficulties and disability, and more fully understanding the nature of skilled reading in adults. This special issue focuses on the potential opportunities and insights that early and richly integrated advanced statistical and computational modeling approaches can provide to our foundational (and translational) understanding of reading. The issue explores how computational and statistical modeling, using both observed and simulated data, can serve as a contact point among research domains and topics, complement other data sources and critically provide analytic advantages over current approaches.

In-Suit Light Exercise (ISLE) Prebreathe Protocol Peer Review Assessment. Part 2; Appendices

NASA Technical Reports Server (NTRS)

Brady, Timothy K.; Polk, James D.

2011-01-01

The performance of extravehicular activity (EVA) by National Aeronautics and Space Administration astronauts involves the risk of decompression sickness. This risk has been mitigated by the use of oxygen "prebreathe" to effectively wash out tissue nitrogen prior to each EVA. Now that the Space Shuttle Program (SSP) is being retired, high-pressure oxygen will become a limited resource. The In-Suit Light Exercise (ISLE) Prebreathe Protocol offers several potential benefits including its potential to save 6 pounds of oxygen per EVA. At the request of the NASA Engineering and Safety Center, the peer review convened on October 14, 2010. The major recommendation of the Review Committee was that the ISLE protocol was acceptable for operational use as a prebreathe option prior to EVA. The appendices to Volume I of the report are contained in this document.

Marine Natural Products from New Caledonia--A Review.

PubMed

Motuhi, Sofia-Eléna; Mehiri, Mohamed; Payri, Claude Elisabeth; La Barre, Stéphane; Bach, Stéphane

2016-03-16

Marine micro- and macroorganisms are well known to produce metabolites with high biotechnological potential. Nearly 40 years of systematic prospecting all around the New Caledonia archipelago and several successive research programs have uncovered new chemical leads from benthic and planktonic organisms. After species identification, biological and/or pharmaceutical analyses are performed on marine organisms to assess their bioactivities. A total of 3582 genera, 1107 families and 9372 species have been surveyed and more than 350 novel molecular structures have been identified. Along with their bioactivities that hold promise for therapeutic applications, most of these molecules are also potentially useful for cosmetics and food biotechnology. This review highlights the tremendous marine diversity in New Caledonia, and offers an outline of the vast possibilities for natural products, especially in the interest of pursuing collaborative fundamental research programs and developing local biotechnology programs.

National Launch System: Structures and materials

NASA Technical Reports Server (NTRS)

Bunting, Jack O.

1993-01-01

The National Launch System provides an opportunity to realize the potential of Al-Li. Advanced structures can reduce weights by 5-40 percent as well as relax propulsion system performance specifications and reduce requirements for labor and materials. The effect on costs will be substantial. Advanced assembly and process control technologies also offer the potential for greatly reduced labor during the manufacturing and inspection processes. Current practices are very labor-intensive and, as a result, labor costs far outweigh material costs for operational space transportation systems. The technological readiness of new structural materials depends on their commercial availability, producibility and materials properties. Martin Marietta is vigorously pursuing the development of its Weldalite 049 Al-Li alloys in each of these areas. Martin Marietta is also preparing to test an automated work cell concept that it has developed using discrete event simulation.

In-Suit Light Exercise (ISLE) Prebreathe Protocol Peer Review Assessment. Volume 1

NASA Technical Reports Server (NTRS)

Brady, Timothy K.; Polk, James D.

2011-01-01

The performance of extravehicular activity (EVA) by National Aeronautics and Space Administration astronauts involves the risk of decompression sickness. This risk has been mitigated by the use of oxygen "prebreathe" to effectively wash out tissue nitrogen prior to each EVA. Now that the Space Shuttle Program (SSP) is being retired, high-pressure oxygen will become a limited resource. The In-Suit Light Exercise (ISLE) Prebreathe Protocol offers several potential benefits including its potential to save 6 pounds of oxygen per EVA. At the request of the NASA Engineering and Safety Center, the peer review convened on October 14, 2010. The major recommendation of the Review Committee was that the ISLE protocol was acceptable for operational use as a prebreathe option prior to EVA. The results from the peer review are contained in this document.

Continuum limbed robots for locomotion

NASA Astrophysics Data System (ADS)

Mutlu, Alper

This thesis focuses on continuum robots based on pneumatic muscle technology. We introduce a novel approach to use these muscles as limbs of lightweight legged robots. The flexibility of the continuum legs of these robots offers the potential to perform some duties that are not possible with classical rigid-link robots. Potential applications are as space robots in low gravity, and as cave explorer robots. The thesis covers the fabrication process of continuum pneumatic muscles and limbs. It also provides some new experimental data on this technology. Afterwards, the designs of two different novel continuum robots - one tripod, one quadruped - are introduced. Experimental data from tests using the robots is provided. The experimental results are the first published example of locomotion with tripod and quadruped continuum legged robots. Finally, discussion of the results and how far this technology can go forward is presented.

Hybrid label-free multiphoton and optoacoustic microscopy (MPOM)

NASA Astrophysics Data System (ADS)

Soliman, Dominik; Tserevelakis, George J.; Omar, Murad; Ntziachristos, Vasilis

2015-07-01

Many biological applications require a simultaneous observation of different anatomical features. However, unless potentially harmful staining of the specimens is employed, individual microscopy techniques do generally not provide multi-contrast capabilities. We present a hybrid microscope integrating optoacoustic microscopy and multiphoton microscopy, including second-harmonic generation, into a single device. This combined multiphoton and optoacoustic microscope (MPOM) offers visualization of a broad range of structures by employing different contrast mechanisms and at the same time enables pure label-free imaging of biological systems. We investigate the relative performance of the two microscopy modalities and demonstrate their multi-contrast abilities through the label-free imaging of a zebrafish larva ex vivo, simultaneously visualizing muscles and pigments. This hybrid microscopy application bears great potential for developmental biology studies, enabling more comprehensive information to be obtained from biological specimens without the necessity of staining.

The Road to Realizing In-Space Manufacturing

NASA Technical Reports Server (NTRS)

Clinton, Raymond G.

2014-01-01

Additive Manufacturing in space offers tremendous potential for dramatic paradigm shift in the development and manufacturing of space architectures. Additive Manufacturing in space offers the potential for mission safety risk reduction for low Earth orbit and deep space exploration; new paradigms for maintenance, repair, and logistics. Leverage ground-based technology developments, process characterization, and material properties databases. Investments are required primarily in the microgravity environment. We must do the foundational work. It's not sexy, but it is required.

The role of non-financial performance measures in predicting hospital financial performance: the case of for-profit system hospitals.

PubMed

Vélez-González, Heltie; Pradhan, Rohit; Weech-Maldonado, Robert

2011-01-01

Non-financial measures have found increasing acceptance in the business world--however, their application in the health care industry remains limited. The purpose of this article is to understand the influence of non-financial measures (efficiency, productivity, and quality) on the financial performance of for-profit system hospitals. The sample consists of 499 for-profit system hospitals in the United States from 1999 to 2002. Data analyzed include the American Hospital Association's Annual Survey, Medicare Cost Reports, Joint Commission's quality scores, and the Centers for Medicare & Medicaid Services' Hospital Case Mix Index. Dependent variables consist of financial measures (operating and total margins), while independent variables include measures of efficiency, productivity, and quality. Our results suggest the influence of non-financial performance measures on financial performance; occupancy rate positively influences financial performance while greater labor intensity may have negative implications for financial performance. In addition, we show that quality positively influences financial performance thereby offering a potential business case for quality. This result has important managerial and policy implications as it may incentivize capital and human resource investments required to improve hospital quality of care.

A model for evaluating the social performance of construction waste management.

PubMed

Yuan, Hongping

2012-06-01

It has been determined by existing literature that a lot of research efforts have been made to the economic performance of construction waste management (CWM), but less attention is paid to investigation of the social performance of CWM. This study therefore attempts to develop a model for quantitatively evaluating the social performance of CWM by using a system dynamics (SD) approach. Firstly, major variables affecting the social performance of CWM are identified and a holistic system for assessing the social performance of CWM is formulated in line with feedback relationships underlying these variables. The developed system is then converted into a SD model through the software iThink. An empirical case study is finally conducted to demonstrate application of the model. Results of model validation indicate that the model is robust and reasonable to reflect the situation of the real system under study. Findings of the case study offer helpful insights into effectively promoting the social performance of CWM of the project investigated. Furthermore, the model exhibits great potential to function as an experimental platform for dynamically evaluating effects of management measures on improving the social performance of CWM of construction projects. Copyright © 2012 Elsevier Ltd. All rights reserved.

Phenotypic Screening Identifies Synergistically Acting Natural Product Enhancing the Performance of Biomaterial Based Wound Healing.

PubMed

Sivasubramanian, Srinivasan; Chandrasekar, Gayathri; Svensson Akusjärvi, Sara; Thangam, Ramar; Sathuvan, Malairaj; Kumar, R B S; Hussein, Hawraa; Vincent, Savariar; Madhan, Balaraman; Gunasekaran, Palani; Kitambi, Satish S

2017-01-01

The potential of multifunctional wound heal biomaterial relies on the optimal content of therapeutic constituents as well as the desirable physical, chemical, and biological properties to accelerate the healing process. Formulating biomaterials such as amnion or collagen based scaffolds with natural products offer an affordable strategy to develop dressing material with high efficiency in healing wounds. Using image based phenotyping and quantification, we screened natural product derived bioactive compounds for modulators of types I and III collagen production from human foreskin derived fibroblast cells. The identified hit was then formulated with amnion to develop a biomaterial, and its biophysical properties, in vitro and in vivo effects were characterized. In addition, we performed functional profiling analyses by PCR array to understand the effect of individual components of these materials on various genes such as inflammatory mediators including chemokines and cytokines, growth factors, fibroblast stimulating markers for collagen secretion, matrix metalloproteinases, etc., associated with wound healing. FACS based cell cycle analyses were carried out to evaluate the potential of biomaterials for induction of proliferation of fibroblasts. Western blot analyses was done to examine the effect of biomaterial on collagen synthesis by cells and compared to cells grown in the presence of growth factors. This work demonstrated an uncomplicated way of identifying components that synergistically promote healing. Besides, we demonstrated that modulating local wound environment using biomaterials with bioactive compounds could enhance healing. This study finds that the developed biomaterials offer immense scope for healing wounds by means of their skin regenerative features such as anti-inflammatory, fibroblast stimulation for collagen secretion as well as inhibition of enzymes and markers impeding the healing, hydrodynamic properties complemented with other features including non-toxicity, biocompatibility, and safety.

Surface-enhanced Raman scattering from AgNP-graphene-AgNP sandwiched nanostructures

NASA Astrophysics Data System (ADS)

Wu, Jian; Xu, Yijun; Xu, Pengyu; Pan, Zhenghui; Chen, Sheng; Shen, Qishen; Zhan, Li; Zhang, Yuegang; Ni, Weihai

2015-10-01

We developed a facile approach toward hybrid AgNP-graphene-AgNP sandwiched structures using self-organized monolayered AgNPs from wet chemical synthesis for the optimized enhancement of the Raman response of monolayer graphene. We demonstrate that the Raman scattering of graphene can be enhanced 530 fold in the hybrid structure. The Raman enhancement is sensitively dependent on the hybrid structure, incident angle, and excitation wavelength. A systematic simulation is performed, which well explains the enhancement mechanism. Our study indicates that the enhancement resulted from the plasmonic coupling between the AgNPs on the opposite sides of graphene. Our approach towards ideal substrates offers great potential to produce a ``hot surface'' for enhancing the Raman response of two-dimensional materials.We developed a facile approach toward hybrid AgNP-graphene-AgNP sandwiched structures using self-organized monolayered AgNPs from wet chemical synthesis for the optimized enhancement of the Raman response of monolayer graphene. We demonstrate that the Raman scattering of graphene can be enhanced 530 fold in the hybrid structure. The Raman enhancement is sensitively dependent on the hybrid structure, incident angle, and excitation wavelength. A systematic simulation is performed, which well explains the enhancement mechanism. Our study indicates that the enhancement resulted from the plasmonic coupling between the AgNPs on the opposite sides of graphene. Our approach towards ideal substrates offers great potential to produce a ``hot surface'' for enhancing the Raman response of two-dimensional materials. Electronic supplementary information (ESI) available: Additional SEM images, electric field enhancement profiles, Raman scattering spectra, and structure-dependent peak ratios. See DOI: 10.1039/c5nr04500b

Phenotypic Screening Identifies Synergistically Acting Natural Product Enhancing the Performance of Biomaterial Based Wound Healing

PubMed Central

Sivasubramanian, Srinivasan; Chandrasekar, Gayathri; Svensson Akusjärvi, Sara; Thangam, Ramar; Sathuvan, Malairaj; Kumar, R. B. S.; Hussein, Hawraa; Vincent, Savariar; Madhan, Balaraman; Gunasekaran, Palani; Kitambi, Satish S.

2017-01-01

The potential of multifunctional wound heal biomaterial relies on the optimal content of therapeutic constituents as well as the desirable physical, chemical, and biological properties to accelerate the healing process. Formulating biomaterials such as amnion or collagen based scaffolds with natural products offer an affordable strategy to develop dressing material with high efficiency in healing wounds. Using image based phenotyping and quantification, we screened natural product derived bioactive compounds for modulators of types I and III collagen production from human foreskin derived fibroblast cells. The identified hit was then formulated with amnion to develop a biomaterial, and its biophysical properties, in vitro and in vivo effects were characterized. In addition, we performed functional profiling analyses by PCR array to understand the effect of individual components of these materials on various genes such as inflammatory mediators including chemokines and cytokines, growth factors, fibroblast stimulating markers for collagen secretion, matrix metalloproteinases, etc., associated with wound healing. FACS based cell cycle analyses were carried out to evaluate the potential of biomaterials for induction of proliferation of fibroblasts. Western blot analyses was done to examine the effect of biomaterial on collagen synthesis by cells and compared to cells grown in the presence of growth factors. This work demonstrated an uncomplicated way of identifying components that synergistically promote healing. Besides, we demonstrated that modulating local wound environment using biomaterials with bioactive compounds could enhance healing. This study finds that the developed biomaterials offer immense scope for healing wounds by means of their skin regenerative features such as anti-inflammatory, fibroblast stimulation for collagen secretion as well as inhibition of enzymes and markers impeding the healing, hydrodynamic properties complemented with other features including non-toxicity, biocompatibility, and safety. PMID:28769790

Nickel–cobalt layered double hydroxide ultrathin nanoflakes decorated on graphene sheets with a 3D nanonetwork structure as supercapacitive materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Tao; Li, Ruiyi; Li, Zaijun, E-mail: zaijunli@263.net

2014-03-01

Graphical abstract: The microwave heating reflux approach was developed for the fabrication of nickel–cobalt layered double hydroxide ultrathin nanoflakes decorated on graphene sheets, in which ammonia and ethanol were used as the precipitator and medium for the synthesis. The obtained composite shows a 3D flowerclusters morphology with nanonetwork structure and largely enhanced supercapacitive performance. - Highlights: • The paper reported the microwave synthesis of nickel–cobalt layered double hydroxide/graphene composite. • The novel synthesis method is rapid, green, efficient and can be well used to the mass production. • The as-synthesized composite offers a 3D flowerclusters morphology with nanonetwork structure. •more » The composite offers excellent supercapacitive performance. • This study provides a promising route to design and synthesis of advanced graphene-based materials with the superiorities of time-saving and cost-effective characteristics. - Abstract: The study reported a novel microwave heating reflux method for the fabrication of nickel–cobalt layered double hydroxide ultrathin nanoflakes decorated on graphene sheets (GS/NiCo-LDH). Ammonia and ethanol were employed as precipitant and reaction medium for the synthesis, respectively. The resulting GS/NiCo-LDH offers a 3D flowerclusters morphology with nanonetwork structure. Due to the greatly enhanced rate of electron transfer and mass transport, the GS/NiCo-LDH electrode exhibits excellent supercapacitive performances. The maximum specific capacitance was found to be 1980.7 F g{sup −1} at the current density of 1 A g{sup −1}. The specific capacitance can remain 1274.7 F g{sup −1} at the current density of 15 A g{sup −1} and it has an increase of about 2.9% after 1500 cycles. Moreover, the study also provides a promising approach for the design and synthesis of metallic double hydroxides/graphene hybrid materials with time-saving and cost-effective characteristics, which can be potentially applied in the energy storage/conversion devices.« less

Floating compression of Ag nanowire networks for effective strain release of stretchable transparent electrodes

NASA Astrophysics Data System (ADS)

Pyo, Jun Beom; Kim, Byoung Soo; Park, Hyunchul; Kim, Tae Ann; Koo, Chong Min; Lee, Jonghwi; Son, Jeong Gon; Lee, Sang-Soo; Park, Jong Hyuk

2015-10-01

Manipulation of the configuration of Ag nanowire (NW) networks has been pursued to enhance the performance of stretchable transparent electrodes. However, it has remained challenging due to the high Young's modulus and low yield strain of Ag NWs, which lead to their mechanical failure when subjected to structural deformation. We demonstrate that floating a Ag NW network on water and subsequent in-plane compression allows convenient development of a wavy configuration in the Ag NW network, which can release the applied strain. A greatly enhanced electromechanical stability of Ag NW networks can be achieved due to their wavy configuration, while the NW networks maintain the desirable optical and electrical properties. Moreover, the produced NW networks can be transferred to a variety of substrates, offering flexibility for device fabrication. The Ag NW networks with wavy configurations are used as compliant electrodes for dielectric elastomer actuators. The study demonstrates their promising potential to provide improved performance for soft electronic devices.Manipulation of the configuration of Ag nanowire (NW) networks has been pursued to enhance the performance of stretchable transparent electrodes. However, it has remained challenging due to the high Young's modulus and low yield strain of Ag NWs, which lead to their mechanical failure when subjected to structural deformation. We demonstrate that floating a Ag NW network on water and subsequent in-plane compression allows convenient development of a wavy configuration in the Ag NW network, which can release the applied strain. A greatly enhanced electromechanical stability of Ag NW networks can be achieved due to their wavy configuration, while the NW networks maintain the desirable optical and electrical properties. Moreover, the produced NW networks can be transferred to a variety of substrates, offering flexibility for device fabrication. The Ag NW networks with wavy configurations are used as compliant electrodes for dielectric elastomer actuators. The study demonstrates their promising potential to provide improved performance for soft electronic devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03814f

Effect of passive polarizing three-dimensional displays on surgical performance for experienced laparoscopic surgeons.

PubMed

Smith, R; Schwab, K; Day, A; Rockall, T; Ballard, K; Bailey, M; Jourdan, I

2014-10-01

Although the potential benefits of stereoscopic laparoscopy have been recognized for years, the technology has not been adopted because of poor operator tolerance. Passive polarizing projection systems, which have revolutionized three-dimensional (3D) cinema, are now being trialled in surgery. This study was designed to see whether this technology resulted in significant performance benefits for skilled laparoscopists. Four validated laparoscopic skills tasks, each with ten repetitions, were performed by 20 experienced laparoscopic surgeons, in both two-dimensional (2D) and 3D conditions. The primary outcome measure was the performance error rate; secondary outcome measures were time for task completion, 3D motion tracking (path length, motion smoothness and grasping frequency) and workload dimension ratings of the National Aeronautics and Space Administration (NASA) Task Load Index. Surgeons demonstrated a 62 per cent reduction in the median number of errors and a 35 per cent reduction in median performance time when using the passive polarizing 3D display compared with the 2D display. There was a significant 15 per cent reduction in median instrument path length, an enhancement of median motion smoothness, and a 15 per cent decrease in grasper frequency with the 3D display. Participants reported significant reductions in subjective workload dimension ratings of the NASA Task Load Index following use of the 3D displays. Passive polarizing 3D displays improved both the performance of experienced surgeons in a simulated setting and surgeon perception of the operative field. Although it has been argued that the experience of skilled laparoscopic surgeons compensates fully for the loss of stereopsis, this study indicates that this is not the case. Surgical relevance The potential benefits of stereoscopic laparoscopy have been known for years, but the technology has not been adopted because of poor operator tolerance. The first laparoscopic operation was carried out using a prototype passive polarizing laparoscopic system in 2010. This is new three-dimensional (3D) technology offers a real option for 3D laparoscopic surgery where previous systems have failed. This study is the first to have been carried out using this technology. It is essential that new technologies are adopted only when there is robust evidence to support their use. Currently, there are concerns about the use of robotic technologies and whether advantages exist for patient care. If there are advantages, 3D must be playing a significant role. If so, perhaps the technology under investigation here offers potential to a greater spectrum of surgeons, as well as being a more affordable option. © 2014 BJS Society Ltd. Published by John Wiley & Sons Ltd.

Conceptual Design for a Dual-Bell Rocket Nozzle System Using a NASA F-15 Airplane as the Flight Testbed

NASA Technical Reports Server (NTRS)

Jones, Daniel S.; Ruf, Joseph H.; Bui, Trong T.; Martinez, Martel; St. John, Clinton W.

2014-01-01

The dual-bell rocket nozzle was first proposed in 1949, offering a potential improvement in rocket nozzle performance over the conventional-bell nozzle. Despite the performance advantages that have been predicted, both analytically and through static test data, the dual-bell nozzle has still not been adequately tested in a relevant flight environment. In 2013 a proposal was constructed that offered a NASA F-15 airplane as the flight testbed, with the plan to operate a dual-bell rocket nozzle during captive-carried flight. If implemented, this capability will permit nozzle operation into an external flow field similar to that of a launch vehicle, and facilitate an improved understanding of dual-bell nozzle plume sensitivity to external flow-field effects. More importantly, this flight testbed can be utilized to help quantify the performance benefit with the dual-bell nozzle, as well as to advance its technology readiness level. This presentation provides highlights of a technical paper that outlines this ultimate goal, including plans for future flights to quantify the external flow field of the airplane near the nozzle experiment, as well as details on the conceptual design for the dual-bell nozzle cold-flow propellant feed system integration within the NASA F-15 Propulsion Flight Test Fixture. The current study shows that this concept of flight research is feasible, and could result in valuable flight data for the dual-bell nozzle.

Conceptual Design for a Dual-Bell Rocket Nozzle System Using a NASA F-15 Airplane as the Flight Testbed

NASA Technical Reports Server (NTRS)

Jones, Daniel S.; Ruf, Joseph H.; Bui, Trong T.; Martinez, Martel; St. John, Clinton W.

2014-01-01

The dual-bell rocket nozzle was first proposed in 1949, offering a potential improvement in rocket nozzle performance over the conventional-bell nozzle. Despite the performance advantages that have been predicted, both analytically and through static test data, the dual-bell nozzle has still not been adequately tested in a relevant flight environment. In 2013 a proposal was constructed that offered a National Aeronautics and Space Administration (NASA) F-15 airplane as the flight testbed, with the plan to operate a dual-bell rocket nozzle during captive-carried flight. If implemented, this capability will permit nozzle operation into an external flow field similar to that of a launch vehicle, and facilitate an improved understanding of dual-bell nozzle plume sensitivity to external flow-field effects. More importantly, this flight testbed can be utilized to help quantify the performance benefit with the dual-bell nozzle, as well as to advance its technology readiness level. Toward this ultimate goal, this report provides plans for future flights to quantify the external flow field of the airplane near the nozzle experiment, as well as details on the conceptual design for the dual-bell nozzle cold-flow propellant feed system integration within the NASA F-15 Propulsion Flight Test Fixture. The current study shows that this concept of flight research is feasible, and could result in valuable flight data for the dual-bell nozzle.

MEMS Using SOI Substrate

NASA Technical Reports Server (NTRS)

Tang, Tony K.

1999-01-01

At NASA, the focus for smaller, less costly missions has given impetus for the development of microspacecraft. MicroElectroMechanical System (MEMS) technology advances in the area of sensor, propulsion systems, and instruments, make the notion of a specialized microspacecraft feasible in the immediate future. Similar to the micro-electronics revolution,the emerging MEMS technology offers the integration of recent advances in micromachining and nanofabrication techniques with microelectronics in a mass-producible format,is viewed as the next step in device and instrument miniaturization. MEMS technology offers the potential of enabling or enhancing NASA missions in a variety of ways. This new technology allows the miniaturization of components and systems, where the primary benefit is a reduction in size, mass and power. MEMS technology also provides new capabilities and enhanced performance, where the most significant impact is in performance, regardless of system size. Finally,with the availability of mass-produced, miniature MEMS instrumentation comes the opportunity to rethink our fundamental measurement paradigms. It is now possible to expand our horizons from a single instrument perspective to one involving multi-node distributed systems. In the distributed systems and missions, a new system in which the functionality is enabled through a multiplicity of elements. Further in the future, the integration of electronics, photonics, and micromechanical functionalities into "instruments-on-a-chip" will provide the ultimate size, cost, function, and performance advantage. In this presentation, I will discuss recent development, requirement, and applications of various MEMS technologies and devices for space applications.

Curvature Effect on the Capacitance of Electric Double Layers at Ionic Liquid/Onion-Like Carbon Interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Guang; Jiang, Deen; Cummings, Peter T

Recent experiments have revealed that onion-like carbons (OLCs) offer high energy density and charging/discharging rates when used as the electrodes in supercapacitors. To understand the physical origin of this phenomenon, molecular dynamics simulations were performed for a room-temperature ionic liquid near idealized spherical OLCs with radii ranging from 0.356 to 1.223 nm. We find that the surface charge density increases almost linearly with the potential applied on electric double layers (EDLs) near OLCs. This leads to a nearly flat shape of the differential capacitance versus the potential, unlike the bell or camel shape observed on planar electrodes. Moreover, our simulationsmore » reveal that the capacitance of EDLs on OLCs increases with the curvature or as the OLC size decreases, in agreement with experimental observations. The curvature effect is explained by dominance of charge overscreening over a wide potential range and increased ion density per unit area of electrode surface as the OLC becomes smaller.« less

On-Wafer Measurement of a Silicon-Based CMOS VCO at 324 GHz

NASA Technical Reports Server (NTRS)

Samoska, Lorene; Man Fung, King; Gaier, Todd; Huang, Daquan; Larocca, Tim; Chang, M. F.; Campbell, Richard; Andrews, Michael

2008-01-01

The world s first silicon-based complementary metal oxide/semiconductor (CMOS) integrated-circuit voltage-controlled oscillator (VCO) operating in a frequency range around 324 GHz has been built and tested. Concomitantly, equipment for measuring the performance of this oscillator has been built and tested. These accomplishments are intermediate steps in a continuing effort to develop low-power-consumption, low-phase-noise, electronically tunable signal generators as local oscillators for heterodyne receivers in submillimeter-wavelength (frequency > 300 GHz) scientific instruments and imaging systems. Submillimeter-wavelength imaging systems are of special interest for military and law-enforcement use because they could, potentially, be used to detect weapons hidden behind clothing and other opaque dielectric materials. In comparison with prior submillimeter- wavelength signal generators, CMOS VCOs offer significant potential advantages, including great reductions in power consumption, mass, size, and complexity. In addition, there is potential for on-chip integration of CMOS VCOs with other CMOS integrated circuitry, including phase-lock loops, analog- to-digital converters, and advanced microprocessors.

Medicated chewing gum--a potential drug delivery system.

PubMed

Chaudhary, Shivang A; Shahiwala, Aliasgar F

2010-07-01

Over the years, patient convenience and patient compliance-orientated research in the field of drug delivery has resulted in bringing out potential innovative drug delivery options. Out of which, medicated chewing gum (MCG) offers a highly convenient patient-compliant way of dosing medications, not only for special population groups with swallowing difficulties such as children and the elderly, but also for the general population, including the young generation. In this review, various formulation ingredients, different manufacturing processes, and assessment of in vivo and in vitro drug release from MCG are thoroughly discussed along with the therapeutic potential and limitations of MCG. Readers will gain knowledge about the rationale and prominent formulation and performance evaluation strategies behind chewing gum as a drug delivery system. The availability of directly compressible co-processed gum material enables rapid, safe and low-cost development of MCG as a drug delivery option. By MCG formulation, revitalization of old products and reformulation of new patented products is possible, to differentiate them from upcoming generics competition in the market.

An evaluation of the utility and limitations of counting motor unit action potentials in the surface electromyogram

NASA Astrophysics Data System (ADS)

Zhou, Ping; Zev Rymer, William

2004-12-01

The number of motor unit action potentials (MUAPs) appearing in the surface electromyogram (EMG) signal is directly related to motor unit recruitment and firing rates and therefore offers potentially valuable information about the level of activation of the motoneuron pool. In this paper, based on morphological features of the surface MUAPs, we try to estimate the number of MUAPs present in the surface EMG by counting the negative peaks in the signal. Several signal processing procedures are applied to the surface EMG to facilitate this peak counting process. The MUAP number estimation performance by this approach is first illustrated using the surface EMG simulations. Then, by evaluating the peak counting results from the EMG records detected by a very selective surface electrode, at different contraction levels of the first dorsal interosseous (FDI) muscles, the utility and limitations of such direct peak counts for MUAP number estimation in surface EMG are further explored.

Idle reduction programs and potential benefits to schools

DOT National Transportation Integrated Search

2010-11-01

School districts in Texas and many other states have, in recent years, increased the walk zones : surrounding schools to a 2-mile perimeter. Inside this perimeter, either no school bus service is : offered, or service is offered only with a fee...

Performance of Nanocomposite Membranes Containing 0D to 2D Nanofillers for CO₂ Separation: A Review.

PubMed

Janakiram, Saravanan; Ahmadi, Mahdi; Dai, Zhongde; Ansaloni, Luca; Deng, Liyuan

2018-05-14

Membrane technology has the potential to be an eco-friendly and energy-saving solution for the separation of CO₂ from different gaseous streams due to the lower cost and the superior manufacturing features. However, the performances of membranes made of conventional polymers are limited by the trade-off between the permeability and selectivity. Improving the membrane performance through the addition of nanofillers within the polymer matrix offers a promising strategy to achieve superior separation performance. This review aims at providing a complete overview of the recent advances in nanocomposite membranes for enhanced CO₂ separation. Nanofillers of various dimensions and properties are categorized and effects of nature and morphology of the 0D to 2D nanofillers in the corresponding nanocomposite membranes of different polymeric matrixes are discussed with regard to the CO₂ permeation properties. Moreover, a comprehensive summary of the performance data of various nanocomposite membranes is presented. Finally, the advantages and challenges of various nanocomposite membranes are discussed and the future research and development opportunities are proposed.

Gaze-independent ERP-BCIs: augmenting performance through location-congruent bimodal stimuli

PubMed Central

Thurlings, Marieke E.; Brouwer, Anne-Marie; Van Erp, Jan B. F.; Werkhoven, Peter

2014-01-01

Gaze-independent event-related potential (ERP) based brain-computer interfaces (BCIs) yield relatively low BCI performance and traditionally employ unimodal stimuli. Bimodal ERP-BCIs may increase BCI performance due to multisensory integration or summation in the brain. An additional advantage of bimodal BCIs may be that the user can choose which modality or modalities to attend to. We studied bimodal, visual-tactile, gaze-independent BCIs and investigated whether or not ERP components’ tAUCs and subsequent classification accuracies are increased for (1) bimodal vs. unimodal stimuli; (2) location-congruent vs. location-incongruent bimodal stimuli; and (3) attending to both modalities vs. to either one modality. We observed an enhanced bimodal (compared to unimodal) P300 tAUC, which appeared to be positively affected by location-congruency (p = 0.056) and resulted in higher classification accuracies. Attending either to one or to both modalities of the bimodal location-congruent stimuli resulted in differences between ERP components, but not in classification performance. We conclude that location-congruent bimodal stimuli improve ERP-BCIs, and offer the user the possibility to switch the attended modality without losing performance. PMID:25249947

Challenges and strategies in applying performance measurement to federal public health programs.

PubMed

DeGroff, Amy; Schooley, Michael; Chapel, Thomas; Poister, Theodore H

2010-11-01

Performance measurement is widely accepted in public health as an important management tool supporting program improvement and accountability. However, several challenges impede developing and implementing performance measurement systems at the federal level, including the complexity of public health problems that reflect multiple determinants and involve outcomes that may take years to achieve, the decentralized and networked nature of public health program implementation, and the lack of reliable and consistent data sources and other issues related to measurement. All three of these challenges hinder the ability to attribute program results to specific public health program efforts. The purpose of this paper is to explore these issues in detail and offer potential solutions that support the development of robust and practical performance measures to meet the needs for program improvement and accountability. Adapting performance measurement to public health programs is both an evolving science and art. Through the strategies presented here, appropriate systems can be developed and monitored to support the production of meaningful data that will inform effective decision making at multiple levels. Published by Elsevier Ltd.

Evaluation of Cache-based Superscalar and Cacheless Vector Architectures for Scientific Computations

NASA Technical Reports Server (NTRS)

Oliker, Leonid; Carter, Jonathan; Shalf, John; Skinner, David; Ethier, Stephane; Biswas, Rupak; Djomehri, Jahed; VanderWijngaart, Rob

2003-01-01

The growing gap between sustained and peak performance for scientific applications has become a well-known problem in high performance computing. The recent development of parallel vector systems offers the potential to bridge this gap for a significant number of computational science codes and deliver a substantial increase in computing capabilities. This paper examines the intranode performance of the NEC SX6 vector processor and the cache-based IBM Power3/4 superscalar architectures across a number of key scientific computing areas. First, we present the performance of a microbenchmark suite that examines a full spectrum of low-level machine characteristics. Next, we study the behavior of the NAS Parallel Benchmarks using some simple optimizations. Finally, we evaluate the perfor- mance of several numerical codes from key scientific computing domains. Overall results demonstrate that the SX6 achieves high performance on a large fraction of our application suite and in many cases significantly outperforms the RISC-based architectures. However, certain classes of applications are not easily amenable to vectorization and would likely require extensive reengineering of both algorithm and implementation to utilize the SX6 effectively.

The mental cost of cognitive enhancement.

PubMed

Iuculano, Teresa; Cohen Kadosh, Roi

2013-03-06

Noninvasive brain stimulation provides a potential tool for affecting brain functions in the typical and atypical brain and offers in several cases an alternative to pharmaceutical intervention. Some studies have suggested that transcranial electrical stimulation (TES), a form of noninvasive brain stimulation, can also be used to enhance cognitive performance. Critically, research so far has primarily focused on optimizing protocols for effective stimulation, or assessing potential physical side effects of TES while neglecting the possibility of cognitive side effects. We assessed this possibility by targeting the high-level cognitive abilities of learning and automaticity in the mathematical domain. Notably, learning and automaticity represent critical abilities for potential cognitive enhancement in typical and atypical populations. Over 6 d, healthy human adults underwent cognitive training on a new numerical notation while receiving TES to the posterior parietal cortex or the dorsolateral prefrontal cortex. Stimulation to the the posterior parietal cortex facilitated numerical learning, whereas automaticity for the learned material was impaired. In contrast, stimulation to the dorsolateral prefrontal cortex impaired the learning process, whereas automaticity for the learned material was enhanced. The observed double dissociation indicates that cognitive enhancement through TES can occur at the expense of other cognitive functions. These findings have important implications for the future use of enhancement technologies for neurointervention and performance improvement in healthy populations.

Combining brain stimulation and video game to promote long-term transfer of learning and cognitive enhancement

PubMed Central

Looi, Chung Yen; Duta, Mihaela; Brem, Anna-Katharine; Huber, Stefan; Nuerk, Hans-Christoph; Cohen Kadosh, Roi

2016-01-01

Cognitive training offers the potential for individualised learning, prevention of cognitive decline, and rehabilitation. However, key research challenges include ecological validity (training design), transfer of learning and long-term effects. Given that cognitive training and neuromodulation affect neuroplasticity, their combination could promote greater, synergistic effects. We investigated whether combining transcranial direct current stimulation (tDCS) with cognitive training could further enhance cognitive performance compared to training alone, and promote transfer within a short period of time. Healthy adults received real or sham tDCS over their dorsolateral prefrontal cortices during two 30-minute mathematics training sessions involving body movements. To examine the role of training, an active control group received tDCS during a non-mathematical task. Those who received real tDCS performed significantly better in the game than the sham group, and showed transfer effects to working memory, a related but non-numerical cognitive domain. This transfer effect was absent in active and sham control groups. Furthermore, training gains were more pronounced amongst those with lower baseline cognitive abilities, suggesting the potential for reducing cognitive inequalities. All effects associated with real tDCS remained 2 months post-training. Our study demonstrates the potential benefit of this approach for long-term enhancement of human learning and cognition. PMID:26902664

Combining brain stimulation and video game to promote long-term transfer of learning and cognitive enhancement.

PubMed

Looi, Chung Yen; Duta, Mihaela; Brem, Anna-Katharine; Huber, Stefan; Nuerk, Hans-Christoph; Cohen Kadosh, Roi

2016-02-23

Cognitive training offers the potential for individualised learning, prevention of cognitive decline, and rehabilitation. However, key research challenges include ecological validity (training design), transfer of learning and long-term effects. Given that cognitive training and neuromodulation affect neuroplasticity, their combination could promote greater, synergistic effects. We investigated whether combining transcranial direct current stimulation (tDCS) with cognitive training could further enhance cognitive performance compared to training alone, and promote transfer within a short period of time. Healthy adults received real or sham tDCS over their dorsolateral prefrontal cortices during two 30-minute mathematics training sessions involving body movements. To examine the role of training, an active control group received tDCS during a non-mathematical task. Those who received real tDCS performed significantly better in the game than the sham group, and showed transfer effects to working memory, a related but non-numerical cognitive domain. This transfer effect was absent in active and sham control groups. Furthermore, training gains were more pronounced amongst those with lower baseline cognitive abilities, suggesting the potential for reducing cognitive inequalities. All effects associated with real tDCS remained 2 months post-training. Our study demonstrates the potential benefit of this approach for long-term enhancement of human learning and cognition.

Using Bayesian Adaptive Trial Designs for Comparative Effectiveness Research: A Virtual Trial Execution.

PubMed

Luce, Bryan R; Connor, Jason T; Broglio, Kristine R; Mullins, C Daniel; Ishak, K Jack; Saunders, Elijah; Davis, Barry R

2016-09-20

Bayesian and adaptive clinical trial designs offer the potential for more efficient processes that result in lower sample sizes and shorter trial durations than traditional designs. To explore the use and potential benefits of Bayesian adaptive clinical trial designs in comparative effectiveness research. Virtual execution of ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) as if it had been done according to a Bayesian adaptive trial design. Comparative effectiveness trial of antihypertensive medications. Patient data sampled from the more than 42 000 patients enrolled in ALLHAT with publicly available data. Number of patients randomly assigned between groups, trial duration, observed numbers of events, and overall trial results and conclusions. The Bayesian adaptive approach and original design yielded similar overall trial conclusions. The Bayesian adaptive trial randomly assigned more patients to the better-performing group and would probably have ended slightly earlier. This virtual trial execution required limited resampling of ALLHAT patients for inclusion in RE-ADAPT (REsearch in ADAptive methods for Pragmatic Trials). Involvement of a data monitoring committee and other trial logistics were not considered. In a comparative effectiveness research trial, Bayesian adaptive trial designs are a feasible approach and potentially generate earlier results and allocate more patients to better-performing groups. National Heart, Lung, and Blood Institute.

When is coercive methadone therapy justified?

PubMed

D'Hotman, Daniel; Pugh, Jonathan; Douglas, Thomas

2018-06-08

Heroin use poses a significant health and economic burden to society, and individuals with heroin dependence are responsible for a significant amount of crime. Owing to its efficacy and cost-effectiveness, methadone maintenance therapy (MMT) is offered as an optional alternative to imprisonment for drug offenders in several jurisdictions. Some object to such 'MMT offers' on the basis that they involve coercion and thus invalidate the offender's consent to MMT. While we find these arguments unpersuasive, we do not attempt to build a case against them here. Instead, we explore whether administration of MMT following acceptance of an MMT offer might be permissible even on the assumption that MMT offers are coercive, and in such a way that the resulting MMT is non-consensual. We argue that non-consensual MMT following an MMT offer is typically permissible. We first offer empirical evidence to demonstrate the substantial benefits to the offender and society of implementing non-consensual MMT in the criminal justice system. We then explore and respond to potential objections to such uses of MMT. These appeal respectively to harm, autonomy, bodily and mental interference, and penal theoretic considerations. Finally, we introduce and dismiss a potential response to our argument that takes a revisionist position, rejecting prevailing incarceration practices. © 2018 John Wiley & Sons Ltd.

When teams shift among processes: insights from simulation and optimization.

PubMed

Kennedy, Deanna M; McComb, Sara A

2014-09-01

This article introduces process shifts to study the temporal interplay among transition and action processes espoused in the recurring phase model proposed by Marks, Mathieu, and Zacarro (2001). Process shifts are those points in time when teams complete a focal process and change to another process. By using team communication patterns to measure process shifts, this research explores (a) when teams shift among different transition processes and initiate action processes and (b) the potential of different interventions, such as communication directives, to manipulate process shift timing and order and, ultimately, team performance. Virtual experiments are employed to compare data from observed laboratory teams not receiving interventions, simulated teams receiving interventions, and optimal simulated teams generated using genetic algorithm procedures. Our results offer insights about the potential for different interventions to affect team performance. Moreover, certain interventions may promote discussions about key issues (e.g., tactical strategies) and facilitate shifting among transition processes in a manner that emulates optimal simulated teams' communication patterns. Thus, we contribute to theory regarding team processes in 2 important ways. First, we present process shifts as a way to explore the timing of when teams shift from transition to action processes. Second, we use virtual experimentation to identify those interventions with the greatest potential to affect performance by changing when teams shift among processes. Additionally, we employ computational methods including neural networks, simulation, and optimization, thereby demonstrating their applicability in conducting team research. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Alternative Splicing in the Hippo Pathway—Implications for Disease and Potential Therapeutic Targets

PubMed Central

Porazinski, Sean; Ladomery, Michael

2018-01-01

Alternative splicing is a well-studied gene regulatory mechanism that produces biological diversity by allowing the production of multiple protein isoforms from a single gene. An involvement of alternative splicing in the key biological signalling Hippo pathway is emerging and offers new therapeutic avenues. This review discusses examples of alternative splicing in the Hippo pathway, how deregulation of these processes may contribute to disease and whether these processes offer new potential therapeutic targets. PMID:29534050

Analysis of Time-on-Task, Behavior Experiences, and Performance in Two Online Courses with Different Authentic Learning Tasks

ERIC Educational Resources Information Center

Park, Sanghoon

2017-01-01

This paper reports the findings of a comparative analysis of online learner behavioral interactions, time-on-task, attendance, and performance at different points throughout a semester (beginning, during, and end) based on two online courses: one course offering authentic discussion-based learning activities and the other course offering authentic…

Novel methodologies for spectral classification of exon and intron sequences

NASA Astrophysics Data System (ADS)

Kwan, Hon Keung; Kwan, Benjamin Y. M.; Kwan, Jennifer Y. Y.

2012-12-01

Digital processing of a nucleotide sequence requires it to be mapped to a numerical sequence in which the choice of nucleotide to numeric mapping affects how well its biological properties can be preserved and reflected from nucleotide domain to numerical domain. Digital spectral analysis of nucleotide sequences unfolds a period-3 power spectral value which is more prominent in an exon sequence as compared to that of an intron sequence. The success of a period-3 based exon and intron classification depends on the choice of a threshold value. The main purposes of this article are to introduce novel codes for 1-sequence numerical representations for spectral analysis and compare them to existing codes to determine appropriate representation, and to introduce novel thresholding methods for more accurate period-3 based exon and intron classification of an unknown sequence. The main findings of this study are summarized as follows: Among sixteen 1-sequence numerical representations, the K-Quaternary Code I offers an attractive performance. A windowed 1-sequence numerical representation (with window length of 9, 15, and 24 bases) offers a possible speed gain over non-windowed 4-sequence Voss representation which increases as sequence length increases. A winner threshold value (chosen from the best among two defined threshold values and one other threshold value) offers a top precision for classifying an unknown sequence of specified fixed lengths. An interpolated winner threshold value applicable to an unknown and arbitrary length sequence can be estimated from the winner threshold values of fixed length sequences with a comparable performance. In general, precision increases as sequence length increases. The study contributes an effective spectral analysis of nucleotide sequences to better reveal embedded properties, and has potential applications in improved genome annotation.

An update on SCARLET hardware development and flight programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, P.A.; Murphy, D.M.; Piszczor, M.F.

1995-10-01

Solar Concentrator Array with Refractive Linear Element Technology (SCARLET) is one of the first practical photovoltaic concentrator array technologies that offers a number of benefits for space applications (i.e. high array efficiency, protection from space radiation effects, a relatively light weight system, minimized plasma interactions, etc.) The line-focus concentrator concept, however, also offers two very important advantages: (1) low-cost mass production potential of the lens material; and (2) relaxation of precise array tracking requirements to only a single axis. These benefits offer unique capabilities to both commercial and government spacecraft users, specifically those interested in high radiation missions, such asmore » MEO orbits, and electric-powered propulsion LEO-to-GEO orbit raising applications. SCARLET is an aggressive hardware development and flight validation program sponsored by the Ballistic Missile Defense Organization (BMDO) and NASA Lewis Research Center. Its intent is to bring technology to the level of performance and validation necessary for use by various government and commercial programs. The first phase of the SCARLET program culminated with the design, development and fabrication of a small concentrator array for flight on the METEOR satellite. This hardware will be the first in-space demonstration of concentrator technology at the `array level` and will provide valuable in-orbit performance measurements. The METEOR satellite is currently planned for a September/October 1995 launch. The next phase of the program is the development of large array for use by one of the NASA New Millenium Program missions. This hardware will incorporate a number of the significant improvements over the basic METEOR design. This presentation will address the basic SCARLET technology, examine its benefits to users, and describe the expected improvements for future missions.« less

SEED Servers: High-Performance Access to the SEED Genomes, Annotations, and Metabolic Models

PubMed Central

Aziz, Ramy K.; Devoid, Scott; Disz, Terrence; Edwards, Robert A.; Henry, Christopher S.; Olsen, Gary J.; Olson, Robert; Overbeek, Ross; Parrello, Bruce; Pusch, Gordon D.; Stevens, Rick L.; Vonstein, Veronika; Xia, Fangfang

2012-01-01

The remarkable advance in sequencing technology and the rising interest in medical and environmental microbiology, biotechnology, and synthetic biology resulted in a deluge of published microbial genomes. Yet, genome annotation, comparison, and modeling remain a major bottleneck to the translation of sequence information into biological knowledge, hence computational analysis tools are continuously being developed for rapid genome annotation and interpretation. Among the earliest, most comprehensive resources for prokaryotic genome analysis, the SEED project, initiated in 2003 as an integration of genomic data and analysis tools, now contains >5,000 complete genomes, a constantly updated set of curated annotations embodied in a large and growing collection of encoded subsystems, a derived set of protein families, and hundreds of genome-scale metabolic models. Until recently, however, maintaining current copies of the SEED code and data at remote locations has been a pressing issue. To allow high-performance remote access to the SEED database, we developed the SEED Servers (http://www.theseed.org/servers): four network-based servers intended to expose the data in the underlying relational database, support basic annotation services, offer programmatic access to the capabilities of the RAST annotation server, and provide access to a growing collection of metabolic models that support flux balance analysis. The SEED servers offer open access to regularly updated data, the ability to annotate prokaryotic genomes, the ability to create metabolic reconstructions and detailed models of metabolism, and access to hundreds of existing metabolic models. This work offers and supports a framework upon which other groups can build independent research efforts. Large integrations of genomic data represent one of the major intellectual resources driving research in biology, and programmatic access to the SEED data will provide significant utility to a broad collection of potential users. PMID:23110173

The use of on-line characterization technologies during the manufacture of nanostructured materials

NASA Astrophysics Data System (ADS)

Barbas, Joana Margarida de Oliveira

Since their potential has become widely recognized, one of the major research lines on polymer-clay nanocomposites has focused on the preparation of well dispersed systems, which involves investigating their compounding (including their structural and morphological characterization) and the determination of their physical and mechanical performances. Currently, there is an understanding that a high degree of dispersion, particularly exfoliation, of the nanoclay is required to improve the overall performance. Although the influencing parameters are known - interfacial adhesion, chemical affinity and operating conditions - the effect of each on the onset and extent of the organoclay dispersion are still subject of debate. Twin screw extrusion allows for control of the main variables (shear, stress and time), but also, due to the typical modular construction, offers a high degree of freedom in creating the adequate screw design and enables knowledgeable alteration of the barrel. These features offer a solid basis for the development and implementation of apt on-line/in-line monitoring techniques, able to follow up the evolution of dispersion of polymer-clay nanocomposites during processing. This research included the validation, implementation and application of a methodology based on inline Near-Infrared (NIR) Spectroscopy for the characterization of the dispersion along the extruder axis. The results showed that the operating conditions have great impact on the dispersion level, but also that degradation may affect the interfacial chemistry of the system, altering the dispersion pathways. Overall the results obtained confirm that NIR is a valid tool for the on-line characterization of these materials, offering the possibility of assessing in real time the clay dispersion, enabling proper corrective and optimization actions over the material characteristics in a timely manner.

NASA's Space Launch System: An Evolving Capability for Exploration

NASA Technical Reports Server (NTRS)

Creech, Stephen D.; Robinson, Kimberly F.

2016-01-01

A foundational capability for international human deep-space exploration, NASA's Space Launch System (SLS) vehicle represents a new spaceflight infrastructure asset, creating opportunities for mission profiles and space systems that cannot currently be executed. While the primary purpose of SLS, which is making rapid progress towards initial launch readiness in two years, will be to support NASA's Journey to Mars, discussions are already well underway regarding other potential utilization of the vehicle's unique capabilities. In its initial Block 1 configuration, capable of launching 70 metric tons (t) to low Earth orbit (LEO), SLS will propel the Orion crew vehicle to cislunar space, while also delivering small CubeSat-class spacecraft to deep-space destinations. With the addition of a more powerful upper stage, the Block 1B configuration of SLS will be able to deliver 105 t to LEO and enable more ambitious human missions into the proving ground of space. This configuration offers opportunities for launching co-manifested payloads with the Orion crew vehicle, and a class of secondary payloads, larger than today's CubeSats. Further upgrades to the vehicle, including advanced boosters, will evolve its performance to 130 t in its Block 2 configuration. Both Block 1B and Block 2 also offer the capability to carry 8.4- or 10-m payload fairings, larger than any contemporary launch vehicle. With unmatched mass-lift capability, payload volume, and C3, SLS not only enables spacecraft or mission designs currently impossible with contemporary EELVs, it also offers enhancing benefits, such as reduced risk, operational costs and/or complexity, shorter transit time to destination or launching large systems either monolithically or in fewer components. This paper will discuss both the performance and capabilities of Space Launch System as it evolves, and the current state of SLS utilization planning.

Qualification of quantum cascade lasers for space environments

NASA Astrophysics Data System (ADS)

Myers, Tanya L.; Cannon, Bret D.; Brauer, Carolyn S.; Crowther, Blake G.; Hansen, Stewart

2014-06-01

Laser-based instruments are enabling a new generation of scientific instruments for space environments such as those used in the exploration of Mars. The lasers must be robust and able to withstand the harsh environment of space, including radiation exposure. Quantum cascade lasers (QCLs), which are semiconductor lasers that emit in the infrared spectral region, offer the potential for the development of novel laser-based instruments for space applications. The performance of QCLs after radiation exposure, however, has not been reported. We report on work to quantify the performance of QCLs after exposure to two different radiation sources, 64 MeV protons and Cobalt-60 gamma rays, at radiation levels likely to be encountered during a typical space flight mission. No significant degradation in threshold current or slope efficiency is observed for any of the seven Fabry-Perot QCLs that are tested.

Surface and Electrical Characterization of Ag/AgCl Pseudo-Reference Electrodes Manufactured with Commercially Available PCB Technologies

PubMed Central

Moschou, Despina; Trantidou, Tatiana; Regoutz, Anna; Carta, Daniela; Morgan, Hywel; Prodromakis, Themistoklis

2015-01-01

Lab-on-Chip is a technology that could potentially revolutionize medical Point-of-Care diagnostics. Considerable research effort is focused towards innovating production technologies that will make commercial upscaling financially viable. Printed circuit board manufacturing techniques offer several prospects in this field. Here, we present a novel approach to manufacturing Printed Circuit Board (PCB)-based Ag/AgCl reference electrodes, an essential component of biosensors. Our prototypes were characterized both structurally and electrically. Scanning Electron Microscopy (SEM) and X-Ray Photoelectron Spectroscopy (XPS) were employed to evaluate the electrode surface characteristics. Electrical characterization was performed to determine stability and pH dependency. Finally, we demonstrate utilization along with PCB pH sensors, as a step towards a fully integrated PCB platform, comparing performance with discrete commercial reference electrodes. PMID:26213940

Graphene wrapped Copper Phthalocyanine nanotube: Enhanced photocatalytic activity for industrial waste water treatment

NASA Astrophysics Data System (ADS)

Mukherjee, Moumita; Ghorai, Uttam Kumar; Samanta, Madhupriya; Santra, Angshuman; Das, Gour P.; Chattopadhyay, Kalyan K.

2017-10-01

To improve the photocatalytic performance of metal phthalocyanine based catalyst, Copper Phthalocyanine (CuPc) functionalized reduced graphene oxide (RGO) nanocomposite has been synthesized through a simple chemical approach. The obtained product was characterized by X-ray diffraction technique (XRD), Fourier transform infrared (FTIR) spectroscopy, Ultraviolet-visible spectroscopy (UV-vis) and High resolution transmission electron microscopy (HRTEM). The photocatalytic activity of the RGO/CuPc nanocomposite was performed by the degradation of Rhodamine B (RhB) under visible light irradiation. The photocatalytic studies revealed that the RGO/CuPc nanocomposite exhibits much stronger catalytic behavior than the pristine CuPc nanotube. A plausible mechanism for the photodegradation of Rhodamine B (RhB) was suggested. The RGO wrapped CuPc nanotube composite materials offer great potential as active photocatalysts for degradation of organic pollutions in industrial waste water.

The NASA Electric Propulsion Program

NASA Technical Reports Server (NTRS)

Callahan, Lisa Wood; Curran, Francis M.

1996-01-01

Nearly all space missions require on-board propulsion systems and these systems typically have a major impact on spacecraft mass and cost. Electric propulsion systems offer major performance advantages over conventional chemical systems for many mission functions and the NASA Office of Space Access and Technology (OSAT) supports an extensive effort to develop the technology for high-performance, on-board electric propulsion system options to enhance and enable near- and far-term US space missions. This program includes research and development efforts on electrothermal, electrostatic, and electromagnetic propulsion system technologies to cover a wide range of potential applications. To maximize expectations of technology transfer, the program emphasizes strong interaction with the user community through a variety of cooperative and contracted approaches. This paper provides an overview of the OSAT electric propulsion program with an emphasis on recent progress and future directions.

The Boom in 3D-Printed Sensor Technology

PubMed Central

Xu, Yuanyuan; Wu, Xiaoyue; Guo, Xiao; Kong, Bin; Zhang, Min; Qian, Xiang; Mi, Shengli; Sun, Wei

2017-01-01

Future sensing applications will include high-performance features, such as toxin detection, real-time monitoring of physiological events, advanced diagnostics, and connected feedback. However, such multi-functional sensors require advancements in sensitivity, specificity, and throughput with the simultaneous delivery of multiple detection in a short time. Recent advances in 3D printing and electronics have brought us closer to sensors with multiplex advantages, and additive manufacturing approaches offer a new scope for sensor fabrication. To this end, we review the recent advances in 3D-printed cutting-edge sensors. These achievements demonstrate the successful application of 3D-printing technology in sensor fabrication, and the selected studies deeply explore the potential for creating sensors with higher performance. Further development of multi-process 3D printing is expected to expand future sensor utility and availability. PMID:28534832

Antibacterial Metallic Touch Surfaces

PubMed Central

Villapún, Victor M.; Dover, Lynn G.; Cross, Andrew; González, Sergio

2016-01-01

Our aim is to present a comprehensive review of the development of modern antibacterial metallic materials as touch surfaces in healthcare settings. Initially we compare Japanese, European and US standards for the assessment of antimicrobial activity. The variations in methodologies defined in these standards are highlighted. Our review will also cover the most relevant factors that define the antimicrobial performance of metals, namely, the effect of humidity, material geometry, chemistry, physical properties and oxidation of the material. The state of the art in contact-killing materials will be described. Finally, the effect of cleaning products, including disinfectants, on the antimicrobial performance, either by direct contact or by altering the touch surface chemistry on which the microbes attach, will be discussed. We offer our outlook, identifying research areas that require further development and an overview of potential future directions of this exciting field. PMID:28773856

Status on Technology Development of Optic Fiber-Coupled Laser Ignition System for Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Trinh, Huu P.; Early, Jim; Osborne, Robin; Thomas, Matthew; Bossard, John

2003-01-01

To pursue technology developments for future launch vehicles, NASA/Marshall Space Flight Center (MSFC) is examining vortex chamber concepts for liquid rocket engine applications. Past studies indicated that the vortex chamber schemes potentially have a number of advantages over conventional chamber methods. Due to the nature of the vortex flow, relatively cooler propellant streams tend to flow along the chamber wall. Hence, the thruster chamber can be operated without the need of any cooling techniques. This vortex flow also creates strong turbulence, which promotes the propellant mixing process. Consequently, the subject chamber concept: not only offer system simplicity, but also enhance the combustion performance. Test results have shown that chamber performance is markedly high even at a low chamber length-to-diameter ratio. This incentive can be translated to a convenience in the thrust chamber packaging.

Feasibility Study of Economics and Performance of Solar Photovoltaics in the Commonwealth of Puerto Rico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salasovich, J.; Mosey, G.

2011-03-01

This report presents the results of an assessment of the technical and economic feasibility of deploying a photovoltaics (PV) system on brownfield sites in the Commonwealth of Puerto Rico. All of the assessed sites are landfills. The sites were assessed for possible PV installations. The cost, performance, and site impacts of different PV options were estimated. The economics of the potential systems were analyzed using an electric rate of $0.119/kWh and incentives offered by Puerto Rico and by the serving utility, PREPA. According to the site production calculations, the most cost-effective system in terms of return on investment is themore » thin-film fixed-tilt technology. The report recommends financing options that could assist in the implementation of such a system.« less

Career on the move: geography, stratification, and scientific impact.

PubMed

Deville, Pierre; Wang, Dashun; Sinatra, Roberta; Song, Chaoming; Blondel, Vincent D; Barabási, Albert-László

2014-04-24

Changing institutions is an integral part of an academic life. Yet little is known about the mobility patterns of scientists at an institutional level and how these career choices affect scientific outcomes. Here, we examine over 420,000 papers, to track the affiliation information of individual scientists, allowing us to reconstruct their career trajectories over decades. We find that career movements are not only temporally and spatially localized, but also characterized by a high degree of stratification in institutional ranking. When cross-group movement occurs, we find that while going from elite to lower-rank institutions on average associates with modest decrease in scientific performance, transitioning into elite institutions does not result in subsequent performance gain. These results offer empirical evidence on institutional level career choices and movements and have potential implications for science policy.

Feasibility Study of Economics and Performance of Solar Photovoltaics at the Former St. Marks Refinery in St. Marks, Florida

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lisell, L.; Mosey, G.

2010-09-01

This report presents the results of an assessment of the technical and economic feasibility of deploying a photovoltaics (PV) system on a brownfield site in St. Marks, Florida. The site was assessed for possible PV installations. The cost, performance, and site impacts of different PV options were estimated. The economics of the potential systems were analyzed using an electric rate of $0.08/kWh and incentives offered in the State of Florida and from the two accessible utilities, Progress Energy and the City of Tallahassee. According to the site production calculations, the most cost-effective system in terms of return on investment ismore » the fixed-tilt thin film technology. The report recommends financing options that could assist in the implementation of such a system.« less

Framework for Deploying a Virtualized Computing Environment for Collaborative and Secure Data Analytics

PubMed Central

Meyer, Adrian; Green, Laura; Faulk, Ciearro; Galla, Stephen; Meyer, Anne-Marie

2016-01-01

Introduction: Large amounts of health data generated by a wide range of health care applications across a variety of systems have the potential to offer valuable insight into populations and health care systems, but robust and secure computing and analytic systems are required to leverage this information. Framework: We discuss our experiences deploying a Secure Data Analysis Platform (SeDAP), and provide a framework to plan, build and deploy a virtual desktop infrastructure (VDI) to enable innovation, collaboration and operate within academic funding structures. It outlines 6 core components: Security, Ease of Access, Performance, Cost, Tools, and Training. Conclusion: A platform like SeDAP is not simply successful through technical excellence and performance. It’s adoption is dependent on a collaborative environment where researchers and users plan and evaluate the requirements of all aspects. PMID:27683665

Austin's Home Performance with Energy Star Program: Making a Compelling Offer to a Financial Institution Partner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zimring, Mark

2011-03-18

Launched in 2006, over 8,700 residential energy upgrades have been completed through Austin Energy's Home Performance with Energy Star (HPwES) program. The program's lending partner, Velocity Credit Union (VCU) has originated almost 1,800 loans, totaling approximately $12.5 million. Residential energy efficiency loans are typically small, and expensive to originate and service relative to larger financing products. National lenders have been hesitant to deliver attractive loan products to this small, but growing, residential market. In response, energy efficiency programs have found ways to partner with local and regional banks, credit unions, community development finance institutions (CDFIs) and co-ops to deliver energymore » efficiency financing to homeowners. VCU's experience with the Austin Energy HPwES program highlights the potential benefits of energy efficiency programs to a lending partner.« less

Career on the Move: Geography, Stratification, and Scientific Impact

PubMed Central

Deville, Pierre; Wang, Dashun; Sinatra, Roberta; Song, Chaoming; Blondel, Vincent D.; Barabási, Albert-László

2014-01-01

Changing institutions is an integral part of an academic life. Yet little is known about the mobility patterns of scientists at an institutional level and how these career choices affect scientific outcomes. Here, we examine over 420,000 papers, to track the affiliation information of individual scientists, allowing us to reconstruct their career trajectories over decades. We find that career movements are not only temporally and spatially localized, but also characterized by a high degree of stratification in institutional ranking. When cross-group movement occurs, we find that while going from elite to lower-rank institutions on average associates with modest decrease in scientific performance, transitioning into elite institutions does not result in subsequent performance gain. These results offer empirical evidence on institutional level career choices and movements and have potential implications for science policy. PMID:24759743

Microwave absorption performance of Ni(OH)2 decorating biomass carbon composites from Jackfruit peel

NASA Astrophysics Data System (ADS)

Guan, Hongtao; Wang, Huiya; Zhang, Yanlin; Dong, Chengjun; Chen, Gang; Wang, Yude; Xie, Jianbin

2018-07-01

The composite material of Ni(OH)2/biomass carbon have been prepared by a facile "carbonization-activation" procedure from Jackfruit peel and a subsequent water-bathing precipitation process. The biomass carbon material after activation (AC) is constituted of small particles and achieves a large specific surface area of 1602 m2/g. After decoration of Ni(OH)2 nanosheets, the Ni(OH)2/AC composites were investigated the microwave absorption performances in 2-18 GHz. The maximum reflection loss of the Ni(OH)2/AC composites reached -23.6 dB at 15.48 GHz with a thickness of 6 mm. Moreover, the fundamental mechanism based on conductivity, the polarization and defects is discussed. The present investigation offers a new possibility for the biomass based fabrication of potential microwave absorbing materials.

Study of ballistic mode Mercury Orbiter missions. Volume 1: Summary report

NASA Technical Reports Server (NTRS)

Hollenbeck, G. R.

1973-01-01

A summary is given of the scope, approach, and major results of the study of ballistic mode Mercury orbit missions (the Mariner Venus-Mercury spacecraft). The performance potential of ballistic flight mode is presented along with a study of alternate flight techniques. Orbit selection considerations are discussed in terms of the thermal environment of Mercury. Orbiter science experiments are summarized. Technology assessments were conducted for major subsystems appropriate to spin-stabilized and three-axis-stabilized spacecraft designs. Conclusions from this study are: ballistic mode Mercury orbiter missions offer adequate performance for effective follow-up of the MVM'73 science findings; the existing and programmed technology base is adequate for implementation of Mercury orbit spacecraft design; and when pending MVM flyby has been accomplished and the results analyzed, the data base will be adequate to support detailed orbiter spacecraft design efforts.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makowska, Małgorzata G., E-mail: malg@dtu.dk; European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund; Theil Kuhn, Luise

High material penetration by neutrons allows for experiments using sophisticated sample environments providing complex conditions. Thus, neutron imaging holds potential for performing in situ nondestructive measurements on large samples or even full technological systems, which are not possible with any other technique. This paper presents a new sample environment for in situ high resolution neutron imaging experiments at temperatures from room temperature up to 1100 °C and/or using controllable flow of reactive atmospheres. The design also offers the possibility to directly combine imaging with diffraction measurements. Design, special features, and specification of the furnace are described. In addition, examples of experimentsmore » successfully performed at various neutron facilities with the furnace, as well as examples of possible applications are presented. This covers a broad field of research from fundamental to technological investigations of various types of materials and components.« less

Career on the Move: Geography, Stratification, and Scientific Impact

NASA Astrophysics Data System (ADS)

Deville, Pierre; Wang, Dashun; Sinatra, Roberta; Song, Chaoming; Blondel, Vincent D.; Barabási, Albert-László

2014-04-01

Changing institutions is an integral part of an academic life. Yet little is known about the mobility patterns of scientists at an institutional level and how these career choices affect scientific outcomes. Here, we examine over 420,000 papers, to track the affiliation information of individual scientists, allowing us to reconstruct their career trajectories over decades. We find that career movements are not only temporally and spatially localized, but also characterized by a high degree of stratification in institutional ranking. When cross-group movement occurs, we find that while going from elite to lower-rank institutions on average associates with modest decrease in scientific performance, transitioning into elite institutions does not result in subsequent performance gain. These results offer empirical evidence on institutional level career choices and movements and have potential implications for science policy.

Heat Treatment of Iron-Carbon Alloys in a Magnetic Field (Phase 2)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ludtka, Gerard Michael

Thermomagnetic processing was shown to shift the phase transformation temperatures and therefore microstructural evolution in the high performance engine valve spring 9254 steel alloy by applying a high magnetic field during cooling. These effects would be anticipated to improve performance such as high cycle fatigue as demonstrated in prior projects. Thermomagnetic processing of gears and crank shafts was constrained by the size of the prototype equipment currently available at ORNL. However, the commercial procurement viability of production scale 9-Tesla, 16-inch diameter bore thermomagnetic processing equipment for truck idler gears up to ~11-inch diameter and potential crank shaft applications was shown,more » as multiple superconducting magnet manufacturing companies (in conjunction with an induction heat treating company, AjaxTOCCO Magnethermic) offered cryogen-free or cryocooler equipment designs to Cummins.« less

Chaining for Flexible and High-Performance Key-Value Systems

DTIC Science & Technology

2012-09-01

store that is fault tolerant achieves high performance and availability, and offers strong data consistency? We present a new replication protocol...effective high performance data access and analytics, many sites use simpler data model “ NoSQL ” systems. ese systems store and retrieve data only by...DRAM, Flash, and disk-based storage; can act as an unreliable cache or a durable store ; and can offer strong or weak data consistency. e value of

Woven TPS Enabling Missions Beyond Heritage Carbon Phenolic

NASA Technical Reports Server (NTRS)

Stackpoole, Mairead; Venkatapathy, Ethiraj; Feldman, Jay

2013-01-01

Woven Thermal Protection Systems (WTPS) is a new TPS concept that is funded by NASAs Office of the Chief Technologist (OCT) Game Changing Division. The WTPS project demonstrates the potential for manufacturing many TPS architectures capable of performances demanded by the many potential solar system exploration missions. Currently, missions that encounter heat fluxes in the range of 1500 4000 W/sq cm and pressures greater than 1.5 atm have very limited TPS options - only one proven material, fully dense Carbon Phenolic, is currently available for these missions. However, fully dense carbon phenolic is only mass efficient at heat fluxes greater than 4000 W/sq cm, and current mission designs suffer this mass inefficiency for lack of an alternative mid-density TPS. WTPS not only bridges this TPS gap but also offers a replacement for carbon phenolic, which itself requires a significant and costly redevelopment effort to re-establish its capability for use in the high heat flux missions recently prioritized in the NRC Decadal survey, including probe missions to Venus, Saturn and Neptune. This presentation will introduce some woven TPS architectures considered in this project and summarize some recent arc jet testing to evaluate the performance of fully dense and mid density WTPS. Performance comparisons to heritage carbon phenolic will be drawn where applicable.

Testing the Effects of the Addition of Videos to a Website Promoting Environmental Breast Cancer Risk Reduction Practices: Are Videos Worth It?

PubMed Central

Perrault, Evan K.; Silk, Kami J.

2013-01-01

Searching for ways to reach wider audiences in more comprehensible ways, health promotion agencies might add videos to their current web offerings. While potentially costly and time consuming to create, the effect of these videos on websites has not received much attention. This study translated research about the potential breast cancer risk for young girls associated with the household chemical PFOA into two websites mothers with young daughters were randomly assigned to view (website with videos vs. website without videos). Results revealed participants in the video condition found the advocated risk protective behaviors easier to perform and stated they were more likely to perform them than those in the non-video condition. Approximately 15 days after exposure, those in the video condition performed on average one more protective behavior than those in the non-video condition. Results also suggest that agencies’ efforts should focus on creating one quality video to place on a homepage, as video views declined the deeper people navigated into the site. Behaviors advocated should also be ones that can have lasting impacts with one-time actions, as effects wore away over time. Additional strategies are discussed for health promoters seeking to create videos to add to their current websites. PMID:25143661

Energetic Combustion Devices for Aerospace Propulsion and Power

NASA Technical Reports Server (NTRS)

Litchford, Ron J.

2000-01-01

Chemical reactions have long been the mainstay thermal energy source for aerospace propulsion and power. Although it is widely recognized that the intrinsic energy density limitations of chemical bonds place severe constraints on maximum realizable performance, it will likely be several years before systems based on high energy density nuclear fuels can be placed into routine service. In the mean time, efforts to develop high energy density chemicals and advanced combustion devices which can utilize such energetic fuels may yield worthwhile returns in overall system performance and cost. Current efforts in this vein are being carried out at NASA MSFC under the direction of the author in the areas of pulse detonation engine technology development and light metals combustion devices. Pulse detonation engines are touted as a low cost alternative to gas turbine engines and to conventional rocket engines, but actual performance and cost benefits have yet to be convincingly demonstrated. Light metal fueled engines also offer potential benefits in certain niche applications such as aluminum/CO2 fueled engines for endo-atmospheric Martian propulsion. Light metal fueled MHD generators also present promising opportunities with respect to electric power generation for electromagnetic launch assist. This presentation will discuss the applications potential of these concepts with respect to aero ace propulsion and power and will review the current status of the development efforts.

Strength training for children and adolescents.

PubMed

Faigenbaum, A D

2000-10-01

The potential benefits of youth strength training extend beyond an increase in muscular strength and may include favorable changes in selected health- and fitness-related measures. If appropriate training guidelines are followed, regular participation in a youth strength-training program has the potential to increase bone mineral density, improve motor performance skills, enhance sports performance, and better prepare our young athletes for the demands of practice and competition. Despite earlier concerns regarding the safety and efficacy of youth strength training, current public health objectives now aim to increase the number of boys and girls age 6 and older who regularly participate in physical activities that enhance and maintain muscular fitness. Parents, teachers, coaches, and healthcare providers should realize that youth strength training is a specialized method of conditioning that can offer enormous benefit but at the same time can result in serious injury if established guidelines are not followed. With qualified instruction, competent supervision, and an appropriate progression of the volume and intensity of training, children and adolescents cannot only learn advanced strength training exercises but can feel good about their performances, and have fun. Additional clinical trails involving children and adolescents are needed to further explore the acute and chronic effects of strength training on a variety of anatomical, physiological, and psychological parameters.

Current status and future prospects of power generators using dielectric elastomers

NASA Astrophysics Data System (ADS)

Chiba, Seiki; Waki, Mikio; Kornbluh, Roy; Pelrine, Ron

2011-12-01

Electroactive polymer artificial muscle (EPAM), known collectively as dielectric elastomers in the literature, has been shown to offer unique capabilities as an actuator and is now being developed for a wide variety of generator applications. EPAM has several characteristics that make it potentially well suited for wave, water current, wind, human motion, and other environmental energy harvesting systems including a high energy density allowing for minimal EPAM material quantities, high energy conversion efficiency independent of frequency of operation and non-toxic and low-cost materials not susceptible to corrosion. Experiments have been performed on push-button and heel-mounted generator devices powered by human motion, ocean wave power harvesters mounted on buoys and water turbines. While the power output levels of such demonstration devices is small, the performance of these devices has supported the potential benefits of EPAM. For example, an electrical energy conversion efficiency of over 70% was achieved with small wave heights. The ability of EPAM to produce hydrogen fuel for energy storage was also demonstrated. Because the energy conversion principle of EPAM is capacitive in nature, the performance is largely independent of size and it should eventually be possible to scale up EPAM generators to the megawatt level to address a variety of electrical power needs.

Polyvalent Display of Biomolecules on Live Cells.

PubMed

Shi, Peng; Zhao, Nan; Lai, Jinping; Coyne, James; Gaddes, Erin R; Wang, Yong

2018-06-04

Surface display of biomolecules on live cells offers new opportunities to treat human diseases and perform basic studies. Existing methods are primarily focused on monovalent functionalization, that is, the display of single biomolecules across the cell surface. Here we show that the surface of live cells can be functionalized to display polyvalent biomolecular structures through two-step reactions under physiological conditions. This polyvalent functionalization enables the cell surface to recognize the microenvironment one order of magnitude more effectively than with monovalent functionalization. Thus, polyvalent display of biomolecules on live cells holds great potential for various biological and biomedical applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Elements of Designing for Cost

NASA Technical Reports Server (NTRS)

Dean, Edwin B.; Unal, Resit

1992-01-01

During recent history in the United States, government systems development has been performance driven. As a result, systems within a class have experienced exponentially increasing cost over time in fixed year dollars. Moreover, little emphasis has been placed on reducing cost. This paper defines designing for cost and presents several tools which, if used in the engineering process, offer the promise of reducing cost. Although other potential tools exist for designing for cost, this paper focuses on rules of thumb, quality function deployment, Taguchi methods, concurrent engineering, and activity based costing. Each of these tools has been demonstrated to reduce cost if used within the engineering process.

Health and Safety Benefits of Small Pressurized Suitport Rovers as EVA Surface Support Vehicles

NASA Technical Reports Server (NTRS)

Gernhardt, Michael L.; Abercromby, Andrew F. J.

2008-01-01

Pressurized safe-haven providing SPE protection and decompression sickness (DCS) treatment capabilities within 20 mins at all times. Up to 50% reduction in time spent in EVA suits (vs. Unpressurized Rovers) for equal or greater Boots-on-Surface EVA exploration time. Reduces suit-induced trauma and provides improved options for nutrition, hydration, and waste-management. Time spent inside SPR during long translations may be spent performing resistive and cardiovascular exercise. Multiple shorter EVAs versus single 8 hr EVAs increases DCS safety and decreases prebreathe requirements. SPRs also offer many potential operational, engineering and exploration benefits not addressed here.

The NASA thermionic-conversion (TEC-ART) program

NASA Technical Reports Server (NTRS)

Morris, J. F.

1977-01-01

The current emphasis is on out-of-core thermionic conversion (TEC). The additional degrees of freedom offer new potentialities, but high-temperature material effects determine the level and lifetime of TEC performance: New electrodes not only raise power outputs but also maintain them regardless of emitter-vapor deposition on collectors. In addition, effective electrodes serve compatibly with hot-shell alloys. Space TEC withstands external and internal high-temperature vaporization problems, and terrestrial TEC tolerates hot corrosive atmospheres outside and near-vacuum inside. Finally, reduction of losses between converter electrodes is essential even though rather demanding geometries appear to be required for some modes of enhanced operation.

Molybdenum Dichalcogenides for Environmental Chemical Sensing

PubMed Central

Zappa, Dario

2017-01-01

2D transition metal dichalcogenides are attracting a strong interest following the popularity of graphene and other carbon-based materials. In the field of chemical sensors, they offer some interesting features that could potentially overcome the limitation of graphene and metal oxides, such as the possibility of operating at room temperature. Molybdenum-based dichalcogenides in particular are among the most studied materials, thanks to their facile preparation techniques and promising performances. The present review summarizes the advances in the exploitation of these MoX2 materials as chemical sensors for the detection of typical environmental pollutants, such as NO2, NH3, CO and volatile organic compounds. PMID:29231879

High-performance flexible hydrogen sensor made of WS2 nanosheet-Pd nanoparticle composite film

NASA Astrophysics Data System (ADS)

Kuru, Cihan; Choi, Duyoung; Kargar, Alireza; Liu, Chin Hung; Yavuz, Serdar; Choi, Chulmin; Jin, Sungho; Bandaru, Prabhakar R.

2016-05-01

We report a flexible hydrogen sensor, composed of WS2 nanosheet-Pd nanoparticle composite film, fabricated on a flexible polyimide substrate. The sensor offers the advantages of light-weight, mechanical durability, room temperature operation, and high sensitivity. The WS2-Pd composite film exhibits sensitivity (R 1/R 2, the ratio of the initial resistance to final resistance of the sensor) of 7.8 to 50 000 ppm hydrogen. Moreover, the WS2-Pd composite film distinctly outperforms the graphene-Pd composite, whose sensitivity is only 1.14. Furthermore, the ease of fabrication holds great potential for scalable and low-cost manufacturing of hydrogen sensors.

Advances in sputtered and ion plated solid film lubrication

NASA Technical Reports Server (NTRS)

Spalvins, T.

1985-01-01

The glow discharge or ion assisted vacuum deposition techniques, primarily sputtering and ion plating, have rapidly emerged and offer great potential to deposit solid lubricants. The increased energizing of these deposition processes lead to improved adherence and coherence, favorable morphological growth, higher density, and reduced residual stresses in the film. These techniques are of invaluable importance where high precision machines tribo-components require very thin, uniform lubricating films (0.2 m), which do not interface with component tolerances. The performance of sputtered MoS2 films and ion plated Au and Pb films are described in terms of film thickness, coefficient of friction, and wear lives.

Microbial-Catalyzed Biotransformation of Multifunctional Triterpenoids Derived from Phytonutrients

PubMed Central

Shah, Syed Adnan Ali; Tan, Huey Ling; Sultan, Sadia; Mohd Faridz, Muhammad Afifi Bin; Mohd Shah, Mohamad Azlan Bin; Nurfazilah, Sharifah; Hussain, Munawar

2014-01-01

Microbial-catalyzed biotransformations have considerable potential for the generation of an enormous variety of structurally diversified organic compounds, especially natural products with complex structures like triterpenoids. They offer efficient and economical ways to produce semi-synthetic analogues and novel lead molecules. Microorganisms such as bacteria and fungi could catalyze chemo-, regio- and stereospecific hydroxylations of diverse triterpenoid substrates that are extremely difficult to produce by chemical routes. During recent years, considerable research has been performed on the microbial transformation of bioactive triterpenoids, in order to obtain biologically active molecules with diverse structures features. This article reviews the microbial modifications of tetranortriterpenoids, tetracyclic triterpenoids and pentacyclic triterpenoids. PMID:25003642

Polymer optical fiber sensors in human life safety

NASA Astrophysics Data System (ADS)

Marques, C. A. F.; Webb, D. J.; Andre, P.

2017-07-01

The current state of research into polymer optical fiber (POF) sensors linked to safety in human life is summarized in this paper. This topic is directly related with new solutions for civil aircraft, structural health monitoring, healthcare and biomedicine fields. In the last years, the properties of polymers have been explored to identify situations offering potential advantages over conventional silica fiber sensing technology, replacing, in some cases, problematic electronic technology used in these mentioned fields, where there are some issues to overcome. POFs could preferably replace their silica counterparts, with improved performance and biocompatibility. Finally, new developments are reported which use the unique properties of POF.